Academic literature on the topic 'Nitrity'
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Journal articles on the topic "Nitrity"
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Gomes, Tamara Maria, João Carlos Cury Saad, Raimundo Leite Cruz, and Carlos Tadeu dos Santos Dias. "AVALIAÇÃO DA CONCENTRAÇÃO E DISTRIBUIÇÃO DE NITRITO, AMÔNIO E NITRATO PROVENIENTES DA URÉIA APLICADA VIA SISTEMA DE IRRIGAÇÃO POR GOTEJAMENTO." IRRIGA 3, no. 2 (August 12, 1998): 29–35. http://dx.doi.org/10.15809/irriga.1998v3n2p29-35.
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AVALIAÇÃO DA CONCENTRAÇÃO E DISTRIBUIÇÃO DE NITRITO, AMÔNIO E NITRATO PROVENIENTES DA URÉIA APLICADA VIA SISTEMA DE IRRIGAÇÃO POR GOTEJAMENTO[1] Tamara Maria GomesBolsista do CNPq, Av. Independência 1592. CEP: 13416-225. Piracicaba-SP João Carlos Cury SaadRaimundo Leite CruzDepartamento de Engenharia Rural. FCA-UNESP, Cx: 237, CEP: 18.603-970, Botucatu Carlos Tadeu dos Santos DiasDepartamento de Matemática e Estatística ESALQ-USP, Cx: 09, CEP: 13418-900, Piracicaba 1 RESUMO O experimento foi conduzido na área experimental de irrigação do Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - UNESP/Câmpus de Botucatu, com o objetivo de avaliar a concentração e distribuição de amônio, nitrito e nitrato provenientes do fertilizante uréia em um sistema de irrigação localizada por gotejamento.As amostras de solução do solo foram coletadas nas profundidades de 25, 50 e 75cm em ambos os lados do gotejador (lado esquerdo e direito) com o uso de cápsulas porosas e as concentrações de amônio, nitrito e nitrato existentes foram determinadas em laboratório, utilizando um espectômetro de fluxo contínuo.A adubação via fertirrigação foi realizada com uréia nas doses de 0, 30 e 60 kg de N..ha-1 em três épocas de aplicação, com.a finalidade de estimar a concentração de nitrato, nitrito e amônio após a ultima fertirrigação. Os valores da concentração de amônio e nitrito encontrados nas amostras de solução do solo nos diferentes tratamentos, profundidades e bulbos não atingiram, na maioria das avaliações, teores utilizados como padrão (> 0,2 mg.L-1 e > 0,05mg.L-1, respectivamente). As concentrações de nitrato na solução do solo para as doses de nitrogênio avaliadas nas três profundidades (25, 50 e 75 cm) estudadas não apresentaram diferença significativa, entretanto a concentração de nitrato em relação a posição do gotejador no sentido do fluxo da água foi estatisticamente maior no lado esquerdo, em virtude da declividade do terreno.A baixa concentração de nitrato encontrada na solução do solo por aplicação de uréia, sugere a realização de outros estudos a respeito da concentração e caminhamento do nitrato no solo com o tempo. Para isso recomenda-se um tempo de espera para a coleta de amostras de solução do solo em torno de 30 a 40 dias após aplicação do fertilizante. Outro fator a ser considerado é com relação a instalação dos extratores de cápsulas porosas, que deve ser realizada pouco tempo (1 a 2 dias) antes das amostragens, evitando obstruções das mesmas. UNITERMO: amônio, nitrito, nitrato, fertirigação, gotejamento, cápsula porosa. GOMES, T. M., SAAD, J. C. C., CRUZ, R. L., DIAS, C.T. dos S. Evaluation of the concentration and distribution of nitrite, ammonium e nitrate deriving from the urea applied through trickle irrigation system 2 ABSTRACT This experiment was conducted in the experimental irrigation area of the Department of Rural Engineering of the Faculty of Agronomicae Sciences - UNESP/ Campus of Botucatu, with the objective of evaluating the concentration and distribution of ammonium, nitrite and nitrate deriving from the fertilizer urea in a trickle irrigation localized system.The samples of the soil solution were collected at depths of 25, 50 and 75 cm on both sides of the trickle (left and right side) using porous capsules and the existing concentrations of ammonium, nitrite and nitrate were determined in the laboratory, using a spectrophotometer of continuous flow.The application of fertilizer through fertigation was done with urea in the levels of 0, 30 and 60 kg of N.ha-1 in three times of application, with the aim to estimate the concentration of nitrate, nitrite and ammonium after the last fertigation.The values of the concentrations of ammonium and nitrite found in the samples of the soil solution in the different treatments, depths and bulbs did not reach, in most of the evaluations, contents utilized as standard (>0.2 mg.L-1 and >0.05 mg.L-1, respectively). The concentrations of nitrate in the soil solution for the levels of nitrogen evaluated at the three depths (25, 50 and 75 cm) studied did not show significative difference, although the concentration of nitrate in relation to the position of the trickle in the direction of the water flow was statistically higher on the left side, due to the slope of the soil.The low concentration of nitrate found in the soil solution due to urea application, suggest the accomplishment of other studies involving the concentration and nitrate movement in the soil with the time. Therefore, we recommend a waiting period for the collection of the samples of the soil solution of about 30 to 40 days after the fertilizer application. Another factor to be considered is the installation of extractor of porous capsules, that must be done shortly after (1 to 2 days) the collection of samples, avoiding obstructions in the porous capsules. KEI-WORDS: ammonium, nitrite, nitrate, fertigation, trickle irrigation system, porous capsules.[1] Parte da dissertação do primeiro autor
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Mawaddah, Aida, Roto Roto, and Adhitasari Suratman. "PENGARUH PENAMBAHAN UREA TERHADAP PENINGKATAN PENCEMARAN NITRIT DAN NITRAT DALAM TANAH (Influence of Addition of Urea to Increased Pollution of Nitrite and Nitrate in The Soil)." Jurnal Manusia dan Lingkungan 23, no. 3 (February 27, 2017): 360. http://dx.doi.org/10.22146/jml.22473.
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ABSTRAKNitrat dan nitrit merupakan sumber nitrogen bagi tanaman. Nitrogen sangat diperlukan tanaman untuk pertumbuhan dan perkembangan. Bentuk-bentuk nitrogen di lingkungan mengalami transformasi sebagai bagian dari siklus nitrogen seperti nitrifikasi dan denitrifikasi. Apabila kadar nitrogen dalam tanah rendah, maka urea digunakan sebagai sumber nitrogen. Perubahan urea menjadi nitrit atau nitrat pada beberapa sampel tanah perlu diketahui. Kadar nitrit dan nitrat yang tinggi dapat meningkatkan pencemaran di dalam tanah. Sampel tanah yang digunakan dalam penelitian ini adalah tanah pasir, tanah sawah, tanah pupuk kompos dan tanah pupuk kandang. Analisis nitrit dan nitrat dilakukan dengan menggunakan pereaksi asam p-amino benzoat (PABA) yang dikopling dengan N-naftiletilendiamin (NEDA) dan reduktor spongy cadmium. Sebelum digunakan untuk analisis nitrit dan nitrat, metode divalidasi terlebih dahulu. Hasil validasi metode analisis nitrit dan nitrat dengan pereaksi PABA/NEDA menunjukkan persentase perolehan kembali masing-masing antara 87,15–100,8% untuk nitrit dan 88,16–105,7% untuk nitrat. Setelah ditambah urea sebesar 0,66 g.kg-1 ke dalam tanah, konsentrasi nitrit dan nitrat pada semua sampel tanah mengalami peningkatan. Dari penelitian ini diketahui bahwa peningkatan kadar nitrit dan nitrat setelah ditambahkan urea sangat dipengaruhi oleh kondisi tanah. ABSTRACTNitrate and nitrite were sources of nitrogen for plants. Nitrogen is indispensable for the growth and development of plants. The forms of nitrogen in the environment undergoes a transformation as part of the nitrogen cycle like nitrification and denitrification. If nitrogen level in the soil is low, urea is used as a source of nitrogen. Changes of urea into nitrite or nitrate in some of soil samples need to be known. The levels of nitrite and nitrate are high can increase pollution in the soil. Some of soil samples which is used in this research were sandy soil, paddy soil, compost soil and manure soil. Analysis of nitrite and nitrate were conducted by using a reagent p-amino benzoic acid (PABA) / N-napthylethylenediamine (NEDA) and spongy cadmium as reductor. Before being used for the analysis of nitrite and nitrate, this method was validated first. The results of validation of nitrite and nitrate analysis method by using a reagents PABA / NEDA showed the percent recovery were respectively 87.15-100.8% for nitrite and 88.16-105.7% for nitrate. After the addition of 0.66 g.kg-1 urea into the soil, nitrite and nitrate concentration in all soil sample has increased. Based on this research was known that the increased levels of nitrite and nitrate after the addition of urea was influenced by soil condition.
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Ayala Armijos, Jose Humberto, Carlos Garcia Gonzalez, Raquel Sanchez Prado, Yiceth Jiron Velez, and Washington Espinoza Ramon. "Efecto de la adición de ácido ascórbico en la degradación de nitratos y nitritos en mortadela / Effect of addition of ascorbic acid in the degradation of nitrate and nitrite in mortadella." Ciencia Unemi 9, no. 20 (December 20, 2016): 85. http://dx.doi.org/10.29076/issn.2528-7737vol9iss20.2016pp85-92p.
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El objetivo de la presente investigación fue evaluar el efecto de la adición de ácido ascórbico (Vitamina C) para reducir la concentración de nitritos y nitratos adicionada a la mortadela como conservante. Se realizaron tres formulaciones de mortadela a las cuales se añadió tres concentraciones diferentes de ácido ascórbico (F1: 0,25 g/kg, F2: 0,50 g/kg y F3: 0,75 g/kg) y un testigo, mediante espectrofotometría UV-Visibles se cuantificó la concentración inicial y la final para comprobar la reducción de nitratos y nitritos y la formación de color y el ácido ascórbico residual se lo cuantificó mediante voltametría. El análisis de varianza aplicado al experimento nos indicó que si existió diferencia significativa (p˂0,05) eentre los tres tratamientos estudiados, se alcanzó reducciones de nitratos del 30,78 % en la F1, 50 % en la F2 y 76 % en la F3, en este caso la reducción de nitratos y valores de nitrito formado de 0,41 mg/kg en la F1, 0,24 mg/Kg en la F2 y 0,04 mg/Kg en la F3, en la formación de nitritos. La F3 presentó el mayor % de reducción de nitratos y la menor cantidad de formación de nitritos. En conclusión la adición de ácido ascórbico a la mortadela reduce la concentración residual de nitratos al cabo de tres días, donde ya no se presentó reducción significativa de este conservante. ABSTRACTThe aim of this research was to evaluate the effect of the addition of ascorbic acid to reduce the concentration of nitrites and nitrates in mortadella. Three formulations of mortadella were tested to which three different concentrations of ascorbic acid (0.25 g / kg, F2: 0.50 g / kg and 0.75 g F3 / kg F1) were added. Through UV-visible spectrophotometry it was quantified the initial and final concentration of nitrates and nitrites and color formation, and the residual ascorbic acid was quantified by voltammetry. The analysis of variance indicated that there was significant difference (p˂0,05) among the three treatments. Nitrate reduction of 30.78% in F1, F2 50% at 76% and the values of F3 and formed nitrite 0.41 mg / kg in F1 0.24 mg / kg was achieved in F2 and 0.04 mg / kg in F3, in the formation of nitrite. F3 showed the highest percentage reduction of nitrates and the least amount of formation of nitrite. In conclusion, the addition of ascorbic acid to mortadella reduces the residual nitrate concentration after three days, where no longer significant reduction of this preservative was presented.
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Chen, J., Q. Xiao, F. H. Wu, Z. M. Pei, J. Wang, Y. G. Wu, and H. L. Zheng. "Nitric oxide emission from barley seedlings and detached leaves and roots treated with nitrate and nitrite." Plant, Soil and Environment 56, No. 5 (May 7, 2010): 201–8. http://dx.doi.org/10.17221/231/2009-pse.
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Nitric oxide (NO) emission from detached barley leaves, roots and whole plants treated with various nitrate or nitrite concentrations under light/dark and aerobic/anaerobic conditions was quantified by using a chemiluminescence detector. NO emission from detached tissues and whole plants treated with moderate nitrate concentration (60mM) was relatively higher under anaerobic condition, and was positively correlated with nitrite concentration. Darkness and anaerobic condition remarkably induced NO emission from detached barley leaves. On the contrary, NO emission from detached roots and whole plants was relatively higher in light. As for whole plants treated with 60mM nitrate and 12mM nitrite, the pattern of NO emission in normal environment was broken by light-dark and aerobic-anaerobic transition. Light and anaerobic condition induced NO emission significantly in the whole plant. The whole barley plant emitted significantly higher amount of NO than detached leaves or roots.
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Drysdale, G. D., H. C. Kasan, and F. Bux. "Assessment of denitrification by the ordinary heterotrophic organisms in an NDBEPR activated sludge sytem." Water Science and Technology 43, no. 1 (January 1, 2001): 147–54. http://dx.doi.org/10.2166/wst.2001.0036.
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The purpose of this study was to isolate and characterise the ordinary heterotrophic organisms (OHOs) present in a NDBEPR system in order to gain a better understanding of the organisms involved in denitrification as well as a more holistic and accurate evaluation of the OHO fraction attributable to denitrification in such a system. Heterotrophic bacteria were isolated from the pre- and secondary anoxic zones of the Darvill NDBEPR process and characterised according to their ability to reduce nitrates and/or nitrites under anoxic conditions. Results showed that the OHO fraction is more complex than currently accepted and, with respect to denitrification, can be more accurately subdivided into five functional groups, four of which interactively contribute to denitrification occurring in the system and one group that are non-denitrifying. These groups were defined as true denitrifiers (bacteria capable of both nitrate and nitrite reduction), incomplete denitrifiers (bacteria that reduced nitrates to nitrites with no further reduction of the nitrites produced), incomplete-nitrite reducers (bacteria capable of both nitrate and nitrite reduction, however, exhibiting severe inhibition of nitrite reduction by nitrates), exclusive nitrite reducers (bacteria only capable of reducing nitrites) and non-denitrifiers (bacteria not capable of nitrate or nitrite reduction).
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Paulionytė, Skaistė, and Aušra Mažeikienė. "BIOLOGICAL NITROGEN REMOVAL FROM WASTEWATER IN COLD PERIOD / BIOLOGINIS AZOTO JUNGINIŲ ŠALINIMAS IŠ NUOTEKŲ ŠALTUOJU LAIKOTARPIU." Mokslas – Lietuvos ateitis 8, no. 4 (October 24, 2016): 468–74. http://dx.doi.org/10.3846/mla.2016.957.
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Today the number of individual wastewater treatment plants in the country is increasing. Popular are biological treatment, activated sludge-based operating units. There are almost no data on how the wastewater disposed of nitrogen compounds, especially in the cold (winter) period. The article analyzes the small domestic wastewater treatment plant AT-6 available in the main clean-up indicators (pH, T, SS, BOD7, nitrate nitrogen, nitrite nitrogen, ammonia nitrogen concentrations). The investigation period as the AT-6 type device treated wastewater in line with the general requirements of the natural environment, effluents (depending on the temperature, odor, pH, and SS, BOD7 concentrations). Nitrate nitrogen and nitrite nitrogen concentrations in the effluent of the device did not exceed the requirements into the natural environment effluents. Ammonium nitrogen concentration in the treated wastewater the entire study period exceeded requirements (5 m. / l) of the discharge into the natural environment. It should be more research during the cold months to confirm this. Šiandien individualių buitinių nuotekų valymo įrenginių skaičius šalyje vis didėja. Populiarūs biologinio valymo veikliojo dumblo pagrindu veikiantys įrenginiai. Beveik nėra duomenų, kaip iš nuotekų šalinami azoto junginiai, ypač šaltuoju (žiemos) laikotarpiu. Straipsnyje analizuojami mažu buitinių nuotekų biologinio valymo įrenginiu AT-6 pasiekiami pagrindiniai išvalymo rodikliai (pH, temperatūra, SM, BDS7, nitratų azoto, nitritų azoto, amonio azoto koncentracijos). Tyrimų laikotarpiu AT-6 tipo įrenginiu išvalytos nuotekos atitiko bendruosius reikalavimus į gamtinę aplinką išleidžiamoms nuotekoms (pagal temperatūrą, kvapą, pH, SM ir BDS7 koncentracijas). Nitratų azoto ir nitritų azoto koncentracijos įrenginio ištakyje neviršijo reikalavimų į gamtinę aplinką išleidžiamoms nuotekoms. Amonio azoto koncentracija išvalytose nuotekose visą tyrimo laikotarpį viršijo reikalavimus (5 mg/l) išleidžiant nuotekas į gamtinę aplinką. Reikėtų atlikti daugiau tyrimų šaltuoju metų laikotarpiu rezultatams patvirtinti.
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Saputra, Alfian Dony, Haeruddin Haeruddin, and Niniek Widyorini. "EFEKTIVITAS KOMBINASI MIKROORGANISME DAN TUMBUHAN AIR Lemna minor SEBAGAI BIOREMEDIATOR DALAM MEREDUKSI SENYAWA AMONIAK, NITRIT, DAN NITRAT PADA LIMBAH PENCUCIAN IKAN." Management of Aquatic Resources Journal (MAQUARES) 5, no. 3 (December 20, 2016): 80–90. http://dx.doi.org/10.14710/marj.v5i3.14393.
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ABSTRAK Limbah pencucian ikan bersumber dari kegiatan pencucian bagian luar dan dalam tubuh ikan. Limbah pencucian ikan memiliki kandungan senyawa amoniak, nitrit, dan nitrat yang tinggi sehingga kemungkinan mempunyai efek negatif bagi lingkungan. Sebagian besar industri pengolahan ikan belum melakukan pengolahan limbah cairnya dengan baik. Bioremediasi merupakan metode biologi dengan memanfaatkan mikroorganisme dan tumbuhan air Lemna minor dalam pengolahan air limbah. Penelitian ini bertujuan untuk mengetahui efektivitas dan pengaruhdari kombinasi mikroorganisme dan Lemna minor dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Metode penelitian yang digunakan adalah eksperimen skala laboratorium dimana wadah percobaan berisi limbah pencucian ikan dengan volume 1 Liter. Desain penelitian yang digunakan yaitu percobaan faktorial 3 x 3 dengan 2 faktor, sehingga terdapat 9 kombinasi perlakuan M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, dan M10L100, dimana “M” faktor konsentrasi mikroorganisme (1 mL/L, 5 mL/L, 10 mL/L), sedangkan “L” faktor bobot biomassaLemna minor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). Variabel utama penelitian adalah amoniak, nitrit, dan nitrat yang didukung oleh temperatur, pH, dan oksigen terlarut. Analisis data dengan menggunakan analisis efektivitas, uji two way Anova, dan uji Beda Nyata Jujur. Hasil penelitian menunjukkan bahwa nilai efektivitas berkisar antara 40,85% - 74,03% (amoniak), 42,21% - 74,10% (nitrit), dan 3,19% - 34,65% (nitrat). Pengaruh interaksi kombinasi mikroorganisme dan Lemna minor yaitu terdapat pengaruh yang nyata dan efektif dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Kata Kunci: Amoniak; Bioremediasi; Lemna minor; Limbah Pencucian Ikan; Mikroorganisme; Nitrat; Nitrit ABSTRACT Fish washery waste derived from washing inner and outer part of fish body.Fish washery waste containshigh ammonia, nitrite, and nitrate which may have negative effect for the environment.Most of the fish processing industry are not doing the processing of waste water properly yet. Bioremediation is a biological method by using microorganisms and aquatic plant Lemna minor in wastewater treatment. The aims of study is to determine the effectiveness anda effect of the use of microorganism and Lemna minor combination in effort to reduce ammonia, nitrite, and nitrate compound in fish washery waste. The method used is laboratory-scale experiments where the experimental containers containing fish washery waste with a volume of 1 Liter. 3 x 3 factorial with 2 factor method design were used, so there are nine treatment combinations of M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, and M10L100, where "M" forconcentrationof microorganisms factor (1 mL/L, 5mL/L, 10 mL/L), while the "L" for biomass weight of Lemna minorfactor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). The main variable of this study are ammonia, nitrite, and nitrate supported by temperature, pH, and Dissolved Oxygen. The data was analyzed using effectiveness analysis, two way Anova, and Least Signifficant Difference methode. The results show that the concentration of ammonia, nitrite, and nitrate decreased after 96 hours for all treatmentscombination. The effectiveness value, ranged between 40.85% - 74.03% (ammonia), 42.21% - 74.10% (nitrite), and 3.19% - 34.65% (nitrate). There is a signifficant influence and effective in combination of microorganisms and Lemna minor to reduce ammonia, nitrite, and nitrate compound in fish washery waste. Keywords: Ammonia; Bioremediation; Lemna minor; Fish Washery Waste; Microorganism; Nitrate;Nitrite
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Ginting, Nahitma, Jansen Silalahi, Tuty Roida Pardede, Sudarmi Sudarmi, and Nerdy Nerdy. "EFFECT OF HARVESTING TIME AT MORNING, AFTERNOON, AND EVENING ON NITRATE AND NITRITE LEVEL IN SPINACH (AMARANTHUS TRICOLOR L.) AND MUSTARD (BRASSICA RAPA L.)." Asian Journal of Pharmaceutical and Clinical Research 11, no. 13 (April 26, 2018): 110. http://dx.doi.org/10.22159/ajpcr.2018.v11s1.26581.
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Objective: The objective of this study is to determine the effect of harvesting time at morning, afternoon, and evening on nitrate and nitrite level in spinach and mustard.Methods: Nitrite identification was done using sulfanilic acid reagent and N-(1-naphthyl) ethylenediamine dihydrochloride. Identification of nitrate was done using reagent ferrous sulfate. Determination of nitrites level was performed visible spectrophotometry using N-(1-naphthyl) ethylenediamine dihydrochloride at maximum wavelength of 540 nm. Nitrate determination is taken with the same method but started with reduction process from nitrate into nitrite using Zn powder in acid condition and then measured as nitrite.Results: Research result shows that there is a change of nitrate and nitrite level from the spinach harvested at morning, afternoon, and evening.Conclusion: Spinach and mustard are better harvested in the morning because it contains nitrite less than in spinach picked afternoon and evening. Level of nitrite increases from morning to afternoon and decreases from afternoon to evening. However, the level of nitrate decreases from morning to afternoon and increases from afternoon to evening.
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Fogarasi, Erzsébet, Ibolya Fülöp, Emanuela Marcu, and Mircea Dumitru Croitoru. "Presence of Nitrate and Nitrite in Well Water in Mureș County." Acta Medica Marisiensis 62, no. 1 (March 1, 2016): 78–81. http://dx.doi.org/10.1515/amma-2015-0063.
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AbstractObjective: One of the most important sources of nitrite and nitrate anions, besides vegetables and meat products, is the drinking water. Presence of nitrite and nitrate in the water in higher concentrations than those set by EFSA (0.5 mg/l nitrite, 50 mg/l nitrate), may have toxicological significance. A quantitative determination of these ions in samples collected from several pleases from Mureș County was made. Methods: Ninety-seven well water samples were tested from 12 different places from Mureș County. We used a simple HPLC-UV ion pair method for the determination of nitrite and nitrate concentrations. Sensitivity of the method enables the quantification for concentrations far below the MCL value. Results: The highest amounts of nitrate and nitrite were measured in Sangeorgiu de Mureș and Cristești. Concentrations of nitrite and nitrate were exceeded in 4.12% and respectively 44.32% of the samples. Conclusions: The high amounts of nitrites and nitrates existing in well water go beyond the expected extent. This pollution can become a health risk since this water is used in human nutrition especially in child nourishment.
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Silalahi, Jansen, Shena Keshia Aritonang, and Muchlisyam. "The Effect of Boiling Time and the Type of Utensil Used on the Nitrite and Nitrate Contents in Carrots (Daucus carota L.)." Indonesian Journal of Pharmaceutical and Clinical Research 1, no. 1 (April 16, 2018): 18–27. http://dx.doi.org/10.32734/idjpcr.v1i1.208.
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Abstract. The purpose of this study was to investigate the effect of boiling time using utensils made of different metal component on thenitrate and nitrite contentsin carrots. The carrots were obtained from Jaranguda Village, Karo Regency, North Sumatra. The utensil types used for boiling were made of stainless steel, what so called periuk and aluminum and boiling time were 5 minutes, 10 minutes and 15 minutes.The determination of nitrite was done by visible spectrophotometer using sulfanilic acid and N-(1-naphthyl) ethylenediamine dihydrochloride reagentsand absorbance was measured at a wavelength of 540 nm. The determinationof nitrate wascarried out by reducing the nitrate into nitrite using Zinc powder and diluted HCl then measured as nitrite. The nitritelevel was then convertedinto nitrate. The result showed that the utensil types and boiling time affected the levels of nitrate and nitrite in carrots. The nitrate and nitrite levels in fresh carrots was 32.14 mg/kg and 24.78 mg/kg respectively. After boiling for 5 minutes, the nitrate and nitrite levels decreased significantly. Further boiling of boiled carrots, the nitrite levelincreased in the aluminum utensil from 11.00 mg/kg to 20.15 mg/kg (83 %); in periuk from 9.18 mg/kg to 16.95 mg/kg (78%) andin stainless steelfrom 8.21 mg/kg to 11.75 mg/kg (43%). While the nitrate level decreased in aluminumutensil from 27.14 mg/kg to 21.08 mg/kg (22%); stainless steel from 16.40 mg/kg to 13.25 mg/kg (19%) and periuk from 20.30 mg/kg to 16.51 mg/kg (18%). The results of this study indicated that the nitrite level increased, while nitrate level decreased with boiling time.The effect of utensil type used on boiling increased nitrite but decreased nitrate level in carrotsand these effects were found that the mostinfluential treatmentwas using utensil made of aluminum.
Keyword: Carrot, Boiling Time, Nitrate, Nitrit, Utensil Type
Dissertations / Theses on the topic "Nitrity"
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Machado, Genikelly Cavalcanti. "Determinação sequencial de nitrato e nitrito por voltametria de pulso diferencial empregando um ultramicroeletrodo de ouro." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-20092010-144502/.
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Este trabalho descreve o desenvolvimento de um método eletroanalítico para determinação sequencial de nitrito (NO2-) e nitrato (NO3-), utilizando como técnica, a voltametria de pulso diferencial. O método se baseia na redução eletroquímica dos íons nitrato sobre um ultramicroeletrodo de ouro modificado in situ com cádmio depositado em regime de subtensão, e na seqüência, a remoção da monocamada de cádmio e a oxidação eletroquímica dos íons nitritos sobre o ultramicroeletrodo não modificado. Os ensaios voltamétricos para determinação quantitativa de nitrato e nitrito foram realizados em solução de NaClO4 0,1 molL-1 + HClO4 1,0x 10-3 molL-1 (pH = 3,3) preparada com água ultrapura. Utilizando as condições experimentais e os parâmetros voltamétricos otimizados, foram construídas curvas analíticas para determinação de nitrito e nitrato separadamente e também para determinação sequencial dos dois analitos. Para a determinação do NO2-, foi observado uma relação linear entre a corrente de pico e a concentração desse íon dentro do intervalo de concentração de 1,0 x 10-5 molL-1 a 1,1 x 10-4 molL-1, com um limite de detecção igual a 1,151 ± 0,091 µmolL-1 e limite de quantificação igual a 3,838 ± 0,091 µmolL-1. Para a determinação do NO3-, também foi observado uma relação linear entre corrente de pico e concentração desse analito dentro do intervalo estudado, que foi de 2,00 x 10-5 molL-1 a 2,50 x 10-4 molL-1. O limite de detecção encontrado foi 4,839 ± 0,275 µmolL-1 e o limite de quantificação 16,131 ± 0,275 µmolL-1. A determinação sequencial de nitrito e nitrato foi avaliada dentro do intervalo de concentração de 5,00 x 10-5 molL-1 a 2,50 x 10-4 molL-1 para NO3- e 1,00 x 10-5 molL-1 a 4,50 x 10-5 para NO2-. Para ambos os casos, a relação entre corrente de pico versus concentração do analito foi linear. Para a determinação sequencial os limites de detecção são 16,177 ± 0,794 µmolL-1 para NO3- e 2,243 ± 0,179 µmolL-1 para NO2- e os limites de quantificação são 53,922 ± 0,794 µmolL-1 para o NO3- e 7,476 ± 0,179 µmolL-1 para o NO2-. Os limites de detecção, os limites de quantificação e demais parâmetros estatísticos apresentados nesse trabalho, foram obtidos a partir de cálculos baseados em procedimentos descritos em Miller e Miller68 e Silva69.This work describes the development of an electroanalytical method for sequential determination of nitrite (NO2-) and nitrate (NO3-), using as a technique, differential pulse voltammetry. The method is based on the electrochemical reduction of nitrate ions on a gold ultramicroelectrode modified in situ by underpotential deposition of cadmium, and subsequently, the removal of cadmium monolayer and the electrochemical oxidation of nitrite on ultramicroelectrode unmodified. The voltammetric analysis for quantitative determination of nitrate and nitrite were carried out in NaClO4 0.1 molL-1 + HClO4 1.0 x 10-3 molL-1 (pH = 3.3) prepared with ultrapure water. Using the optimized experimental conditions and voltammetric parameters, analytical curves were constructed for determination of nitrite and nitrate separately and for sequential determination of the two analytes. The relationship between peak current and concentration of NO2- were found to be linear in the concentration range between 1.0 x 10-5 molL-1 and 1.1 x 10-4 molL-1, with a detection limit of 1.151 ± 0.091 µmolL-1 and quantification limit of 3.838 ± 0.091 µmolL-1. For determination of NO3- was also observed a linear relationship between peak current and concentration of analyte within the concentration range studied, which was from 2.00 x 10-5 molL-1 to 2.50 x 10-4 molL-1. The detection limit was 4.839 ± 0.275 µmolL-1 and the quantification limit was 16.131 ± 0.275 µmolL-1. The sequential determination of nitrite and nitrate was assessed within concentration range from 5.00 x 10-5 molL-1 to 2.50 x 10-4 molL-1 for NO3- and from 1.00 x 10-5 molL-1 to 4.50 x 10-5 for NO2-. In both cases, the relationship between peak current versus analyte concentration were found to be linear. The detection limits for sequential determination are 16.177 ± 0.794 µmolL-1 for NO3- and 2.243 ± 0.179 µmolL-1 for NO2- and the quantification limits are 53.922 ± 0.794 µmolL-1 for NO3- and 7.476 ± 0.179 µmolL-1 for NO2-. The detection and quantification limits and other statistical parameters presented in this work were obtained from calculations based on procedures described in Miller and Miller68 and Silva69.
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Jiquiriçá, Paulo Ricardo Ilha. "Efeitos letais e subletais da poluição por nitrogênio em larvas de anuros." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-13122010-144109/.
Full textAbstract:
As atividades humanas vêm aumentando dramaticamente a quantidade de nitrogênio inorgânico liberado nos ecossistemas, seja através da aplicação de fertilizantes na agricultura, da descarga de dejetos humanos e de seus rebanhos, ou da queima de combustíveis fósseis. Os excessos de nitrogênio são eventualmente transportados para corpos d´água, onde podem, na forma de nitrato, nitrito e amônio, atingir concentrações tóxicas para organismos aquáticos. Nesta pesquisa tive dois objetivos principais. O primeiro foi testar em laboratório a toxicidade relativa dos íons nitrato, nitrito e amônio, e a variação interespecífica na sensibilidade a esses íons, em larvas de cinco espécies de anuros (Rhinella ornata, Hypsiboas faber, Hypsiboas pardalis, Physalaemus cuvieri e Physalaemus olfersii ). Para isso utilizei bioensaios seguindo protocolos internacionalmente padronizados para testes de ecotoxicidade com organismos aquáticos, e que portanto permitem máximas reprodutibilidade e comparabilidade de resultados entre compostos, espécies, e laboratórios. No entanto, estes bioensaios carecem de realismo uma vez que simulam um cenário de exposição aguda a altas concentrações de contaminantes quando na natureza o cenário de exposição tende a ser crônico e prolongado a baixas concentrações. Além disso, bioensaios usam mortalidade como principal variável de resposta, quando também efeitos subletais podem influenciar a persistência de populações ao modular o sucesso dos indivíduos. Por isso, meu segundo objetivo foi testar em laboratório se concentrações relativamente baixas e ecologicamente relevantes de nitrato, nitrito e amônio podem afetar a sobrevivência, o crescimento, o desenvolvimento e o comportamento das larvas de R. ornata, P. cuvieri e H. faber. Demonstrei através dos bioensaios de exposição aguda que nitrato, a forma mais abundante na natureza, é de baixa toxicidade quando comparada a nitrito e amônio. Demonstrei também que há significativa variação interespecífica na sensibilidade ao nitrogênio inorgânico, e que o ranqueamento de sensibilidade das espécies ao nitrato e ao nitrito foram similares, possivelmente por conta de mecanismos comuns de ação tóxica. Através de experimentos de exposição crônica demonstrei que concentrações relativamente baixas de nitrogênio inorgânico podem causar efeitos letais e subletais às larvas de anuros se houver exposição prolongada. O nitrato causou redução no desenvolvimento larval de P. cuvieri e o amônio na sobrevivência e nas taxas de atividade nos girinos de H. faber. A exposição crônica ao nitrito também reduziu significativamente a sobrevivência das três espécies testadas, o crescimento de H. faber e as taxas de atividade de R. ornata. Contudo, é improvável que as concentrações de nitrito que manipulei em laboratório sejam comuns na natureza, especialmente em condições aeróbicas. Esta pesquisa, além de fornecer importantes informações sobre os possíveis efeitos da poluição por nitrogênio em larvas de anuros, contribui para o avanço da ecotoxicologia no Brasil ao estabelecer as bases para o emprego de espécies nativas de anfíbios como sistema-modelo experimental. Estudos futuros que almejem avaliar o risco ambiental da contaminação por nitrogênio deverão por um lado monitorar concentrações em hábitats naturais e por outro avaliar as consequências das interações sinérgicas entre nitrogênio inorgânico e outros estressores físicos, químicos ou biológicos para larvas de anfíbios.Human activities dramatically increased the amount of inorganic nitrogen released in ecosystems through the application of fertilizers in agriculture, the generation of human and livestock waste, and the combustion of fossil fuels. This nitrogen eventually reaches water bodies where it can, in the form of nitrate, nitrite and ammonium, be toxic to aquatic organisms. In this study I had two main objectives. The first was to test the relative toxicity of nitrate, nitrite and ammonium, and the interspecific variation in sensitivity to these ions, in tadpoles of five anuran species (Rhinella ornata, Hypsiboas faber, Hypsiboas pardalis, Physalaemus cuvieri and Physalaemus olfersii ). This objective was accomplished by laboratory bioassays following internationally standardized protocols for ecotoxicity tests with aquatic organisms, therefore allowing maximum reproducibility and comparability of results among compounds, species and laboratories. However, these bioassays lack realism for simulating a scenario of acute exposure to high concentrations of contaminants, while exposure in nature tends to be chronic and prolonged at low concentrations. Furthermore, bioassays use mortality as the main response variable, whereas sublethal effects may also influence the persistence of populations by modulating individual success. My second objective was therefore to test in the laboratory if low and environmentally relevant concentrations of nitrate, nitrite and ammonium affect survival, growth, development and behavior of R. ornata, P. cuvieri and H. faber larvae. Through acute exposure bioassays I demonstrated that nitrate, the most abundant N form in nature, has low toxicity when compared to nitrite and ammonium. I also demonstrated that there is significant interspecific variation in the sensitivity to inorganic nitrogen, and that the ranking of species sensitivity to nitrate and nitrite were similar, possibly due to common mechanisms of toxic action. Through chronic exposure I demonstrated that relatively low concentrations of inorganic nitrogen can cause lethal and sublethal effects on anuran larvae if there is extended exposure. Nitrate decreased developmental rate in P. cuvieri and ammonia decreased survival and activity rates in H. faber tadpoles. Chronic exposure to nitrite also significantly reduced survival of all three species tested, growth of H. faber and activity rates of R. ornata. However, it is unlikely that the concentrations of nitrite manipulated in the laboratory are common in nature, especially in aerobic conditions. This is the first study to document deleterious effects of nitrogen pollution to Brazilian amphibian species, and contributes to the development of ecotoxicology in Brazil by establishing the basis for the employment of native amphibians as model experimental system. Future studies that aim to assess the environmental risk of nitrogen contamination should monitor concentrations in natural habitats and evaluate the effects of synergistic interactions between inorganic nitrogen and other physical, chemical or biological stressors to amphibian larvae.
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Pinheiro, Lucas Cézar. "Estudo de mecanismos anti-hipertensivos do nitrito de sódio na hipertensão renovascular experimental." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/17/17133/tde-18032015-230532/.
Full textAbstract:
O NO regula diversos sistemas orgânicos. No sistema cardiovascular participa ativamente na regulação do tônus vascular entre outras funções. Disfunções na produção ou disponibilidade de NO podem comprometer sua atuação fisiológica. No âmbito vascular isto pode participar da hipertensão. Além da produção de NO pelas óxido nítrico sintases, outras vias paralela de produção fisiológica de NO a partir do nitrito tem sido descritas. O nitrito é o produto inicial da oxidação do NO, sendo posteriormente oxidado a nitrato. Sabe-se que estas três moléculas formam um ciclo dentro do organismo, onde o nitrato é excretado na saliva e convertido a nitrito pelas bactérias bucais.Este nitrito é deglutido com a saliva e exerce seus efeitos, através da conversão a NO. A conversão de nitrito a NO pode ocorrer de forma enzimática ou não enzimática. Como forma não enzimática, o nitrito é convertido a NO pela reação com H+. Esta redução ocorre principalmente no estômago. Esta tese visa elucidar possíveis mecanismos responsáveis pelos efeitos anti-hipertensivos do nitrito de sódio. Avaliamos ratos 2 rins 1 clipe (2R1C) tratados com nitrito e nitrato e verificamos os efeitos anti-hipertensivo destes. De forma Interessante, o aumento do pH gástrico com omeprazol impediu o efeito anti-hipertensivo tanto do nitrito quanto do nitrato. O omeprazol não gerou qualquer diferença na concentração plasmática de nitrito e nitrato. Foi verificado que o tratamento com nitrito e nitrato resultou em aumento das espécies nitrosiladas no plasma e este aumento foi impedido pelo omeprazol. Também testamos a influência do ciclo entero-salivar no efeito do nitrito e nitrato. Verificamos que o tratamento com enxaguante bucal levou ao bloqueio do efeito anti-hipertensivo do nitrato, mas não alterou este efeito nos animais tratados com nitrito. Em todas as abordagens experimentais o efeito anti-hipertensivo do nitrito apenas ocorreu quando houve aumento da concentração plasmática de espécies nitrosiladas.Nitric Oxide plays many functional roles in physiological systems. In the cardiovascular system it participates in a unique way in the regulation of vascular tone among other functions. Dysfunctions in the production or availability of NO may compromise their physiological activity and participate in hypertension. Besides the production of NO by the nitric oxide synthase, other physiological pathways of NO production from nitrite have been described. The nitrite and nitrate are oxidation products of NO. Further nitrite is oxidized to nitrate. These three molecules are known to forma cycle in the body. Nitrate is excreted in saliva and reduced to nitrite by oral bacteria. Nitrite then is swallowed with the saliva and exerts its effects through conversion to NO. The conversion of nitrite to NO may occur by enzymatic or non-enzymatic manner. As a non-enzymatic way nitrite is reduced to NO by reaction with H+.This reaction occurs mainly in the stomach. This thesis aims to elucidate possible mechanisms responsible for the antihypertensive effects of sodium nitrite. We studied 2K1C rats treated with nitrite and nitrate and checked anti-hypertensive effects of these molecules. The increased gastric pH by omeprazole prevented the anti-hypertensive effect of nitrite and nitrate. Omeprazole did not cause any differences in plasma nitrite and nitrate. It was found that treatment with nitrite and nitrate resulted inincreased nitrosylated species in the plasma, and this increase was blocked by omeprazole. We also tested the influence of the entero-salivarycycle effect of nitrite and nitrate. We found that treatment with mouthwash blunted the antihypertensive effect of nitrate but this effect did not change in animals treated with nitrite. Interestingly in all experimental approaches the anti-hypertensive effect of nitrite only occurred when there was an increase in the plasma concentration of nitrosylated species
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Petersson, Joel. "Nitrate, Nitrite and Nitric Oxide in Gastric Mucosal Defense." Doctoral thesis, Uppsala University, Department of Medical Cell Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8624.
Full textAbstract:
The human stomach normally contains high levels of bioactive nitric oxide (NO). This NO derives from salivary nitrate (NO3-) that is converted to nitrite (NO2-) by oral bacteria and thereafter non-enzymatically reduced in the acidic gastric lumen to NO. Nitrate is a common component in vegetables, and after ingestion it is absorbed in the small intestine. Interestingly, circulating nitrate is then concentrated by the salivary glands. Hence, intake of nitrate-rich vegetables results in high levels of NO in the stomach. The physiological effects of the high concentration of NO gas normally present in the gastric lumen have been hitherto unknown, and the present investigations were therefore conducted to address this issue.
NO produced in the gastric lumen after nitrate ingestion increased gastric mucosal blood flow and the thickness of the firmly adherent mucus layer in the stomach. The blood flow and mucus layer are essential defense mechanisms that protect the mucosa from luminal acid and noxious agents. Nonsteroidal antiinflammatory drugs (NSAID) are commonly prescribed and effective drugs for treating pain and inflammation, but are associated with severe gastrointestinal side effects. We demonstrated that a nitrate-rich diet protects against NSAID-induced gastric damage, as a result of the increased formation of NO in the stomach. We also showed that the gastroprotective effect attributed to nitrate depended completely on conversion of nitrate to nitrite by the bacterial flora colonizing the tongue, and that the oral microflora is therefore important in regulating physiological conditions in the stomach.
In summary, this thesis challenges the current dogma that nitrate intake is hazardous, and on the contrary suggests that dietary nitrate plays a direct role in regulating gastric homeostasis. It is likely that a sufficient supply of nitrate in the diet together with the oral microflora is essential for preventing pathological conditions in the gastrointestinal tract.
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Castro, Leonidia Maria de. "Interferência dos metais zinco, chumbo e cobre, no processo de nitrificação no tratamento de efluentes de uma indústria química: estudo de caso." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-27012017-162144/.
Full textAbstract:
Durante o estudo de um sistema de tratamento de efluentes de uma indústria química, contendo em suas águas residuárias vários metais pesados foi observada a ineficiência no processo de nitrificação do efluente tratado. Diante dessa constatação, desenvolveu-se este trabalho visando estudar as interferências dos metais pesados, Pb2+, Zn2+ e Cu2+ no desempenho do processo de nitrificação em um sistema similar de tratamento. Para observação dos efeitos dos metais Zn2+, Pb2+ e Cu2+ isoladamente, foram montados 3 reatores e simuladas as concentrações afluentes do tanque de aeração da indústria. Outros três reatores alimentados com soluções contendo Zn+Cu, Zn+Pb e Pb+Cu utilizados para observação de possíveis efeitos de sinergismo e antagonismo. Um outro reator foi alimentado com a solução dos três metais (Zn2+, Cu2+ e Pb2+). Todos os reatores, recebendo adição de metal ou não, apresentaram concentrações muito elevadas de nitrito. Na realização do ensaio de NMP ficou evidente a inibição dos organismos oxidantes de nitrito, que pode ter ocorrido pela alta concentração do próprio nitrito, ácido nitroso ou amônia livre. Efeitos dos metais Zn2+ e Cu2+ não foram evidentes, o Pb2+ foi o único metal que apresentou efeito de inibição no processo de nitrificação. Os reatores que receberam combinação de íons metálicos não evidenciaram efeitos de sinergismo nem antagonismo, sendo que o reator que recebeu adição dos três íons apresentou menor eficiência.During the study of the chemical industry effluent treatment system containing, several heavy metals, was observed an inefficiency in the nitrification process in final effluent. Therefore, this work was deve!oped to find out ofthe study of the interference of the heavy metals, Pb2+, Zn2+ and Cu2+ on the performance of nitrification process in a similar system of treatment. For observation of the effects of metals Zn2+, Pb2+ and Cu2+ separately, were established three reactors and simulate the influent concentration in the aeration tank of the industry. Other three reactors were fed with solution containing Zn+Cu, Zn+Pb and Pb+Cu for observation of possible synergism or antagonism effects. The other reactor was fed with a solution of the three metals (Zn2+, Cu2+ and Pb2+). All the reactors, receiving the addition of metaIs or not, presented very high concentrations of nitrite. In the realization of the test of NMP, the inhibition of the nitrite oxidizers organisms was evident, that might have happened due to high concentration of nitrous acid, free ammonia and nitrite. The effects of the metals Zn2+ and Cu2+ were not evident; but the Pb2+ was the only metal that presented inhibition effect in the nitrification process. The reactors that received the metallic ion combination didn\'t evidence neither synergism nor antagonism effects, however the reactor that received the addition of the three ions presented smaller efficiency.
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Bescós, García Raúl. "The effect of nitric oxide donors on human performance." Doctoral thesis, Universitat de Barcelona, 2011. http://hdl.handle.net/10803/62896.
Full textAbstract:
Nitric oxide or nitrogen monoxide (NO) is a tiny free radical gas. The discovery of this intriguing molecule has revolutionized physiology and pharmacology research during the last 20 years. Currently, it is known that NO is endogenously synthesized by several molecules and tissues via two pathways: the synthase-dependent pathway and the synthase-independent pathway. In the first, the amino acid L-arginine is the main donnor of NO synthesis. In the second, inorganic nitrate is the main substrate for the synthesis of this molecule. Interestingly, both pathways are directly connected. While the synthase-dependent pathway is oxygen dependent, the synthase-independent metabolic route is greatly facilitated under hypoxia conditions. Thus, these mechanisms of NO production regulate levels of NO in the tissues. An adequate production of NO is important because it plays an essential role in mechanisms related with vasodilatation and blood flow distribution. Additionally, NO modulates other important functions in the human body such as mitochondrial respiration and immune mechanisms. For all these reasons, the interest for dietary NO donors have increased during the last years. It has been suggested that the consumption of food rich in L-arginine or in inorganic nitrate may enhance NO availability in the human body. This hypothesis has not been unnoticed in exercise physiology. In fact, it has been suggested that supplementation with NO donors may improve the cardio-respiratory response, as well as the tolerance to endurance exercise in humans. However, there is a lack of studies analyzing this issue. Therefore, the aim of this doctoral thesis was to assess the effect of L-arginine and inorganic nitrate in the cardio-respiratory and metabolic response of healthy humans.
To develop this aim, three studies and one review were carried out. In the first, it was found that L-arginine supplementation during three days at several doses, between 5.5 and 20.5 g/day was not effective to increase plasma markers of NO, as well as the cardio-respiratory and metabolic response during endurance test. In the second study we found that acute dose of inorganic nitrate supplementation (10 mg/kg of body mass) raised significantly plasma levels of nitrate and nitrite. However, this effect did not report an improvement in the cardio-respiratory response at low-to-moderate intensities of exercise. However, at maximal work loads of exercise dietary nitrate induced significantly reduction of oxygen consumption (VO2peak) compared with placebo. Other cardio-respiratory parameters, as well as blood lactate concentration did not differ between nitrate and placebo. In addition, exercise performance measured as time to exhaustion during an incremental test did not increase compared with placebo. All these findings together suggested that at higher intensities of exercise energy production became more efficient after inorganic nitrate ingestion. Accordingly, in the third study it was analyzed the effect of dietary inorganic nitrate ingestion for three days during endurance exercise in a cycle ergometer at high intensity (time-trial of 40-min). Results of this study showed that nitrate supplementation did not increase significantly plasma levels of nitrite, as well as enhance performance in healthy subjects. Interestingly, a significant, negative correlation was found between change in nitrite and endurance capacity measured as VO2peak during the exercise test. These results indicated that the effect of dietary nitrate ingestion was lower in subjects with high cardiovascular capacity compared with subjects with poor tolerance capacity to endurance exercise. This fact is very important, since it is known that endurance training increase values of VO2peak in sedentary population and this fact is correlated with lower incidence of cardiovascular diseases. These and other important conclusions of these studies are included in the last work of this thesis which was a review article.L’òxid nítric (NO) es un radical lliure alliberat per diverses molècules i teixits en l’organisme humà. El descobriment d’aquesta intrigant molècula ha revolucionat la recerca en el camp de la fisiologia i la farmacologia durant els últims 20 anys. Actualment, es coneix que la alliberació de NO per part de les cèl•lules endotelials estimula el procés de vasodilatació. A més, també es coneix que aquesta molècula es un important regulador de la respiració mitocondrial i del sistema immunològic. Totes aquestes funcions han generat un gran interès per els precursors nutricionals de NO. En l’àmbit de la fisiologia de l’exercici físic s’ha suggerit que la suplementació amb alguna d’aquestes substancies (L-arginina o nitrat inorgànic) pot millorar la tolerància a l’exercici físic de resistència. No obstant, hi ha molta controvèrsia en els resultats dels estudis que han analitzat aquesta hipòtesi. Per tant, l’objectiu principal d’aquesta tesi doctoral va ser analitzar els efectes dels principals precursors de NO, L-arginina i nitrat inorgànic, en la resposta cardiorrespiratòria i metabòlica durant l’exercici físic de caràcter aeròbic en humans. Per dur a terme aquest objectiu es van realitzar 3 estudis i una revisió bibliogràfica. Els principals resultats d’aquests estudis van mostrar que la suplementació de L-arginina en diferents dosis no va ser efectiva per augmentar el marcadors plasmàtics de NO, així com, la resposta cardiorrespiratòria i metabòlica durant un exercici físic aeròbic en intensitats moderades. En referència als nitrat inorgànic, es va observar que la suplementació augmenta els nivells d’aquests compostos en plasma. No obstant, aquest fet no es va correlacionar amb una millora de la tolerància a l’exercici físic de resistència. A més, es va observar una correlación negativa i significativa entre l’augment dels nitrits plasmàtics i la potència aeròbica màxima (VO2max). Tots aquests resultats van ser àmpliament tractats en l’últim treball (revisió bibliogràfica) d’aquesta tesi. En resum, l’ingesta nutricional de L-arginina i/o nitrat inorgànic no resulta efectiva per millorar la resposta cardiorrespiratòria i la tolerància a l’exercici físic de resistència en humans sans i entrenats físicament.
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Melchert, Wanessa Roberto. "Desenvolvimento de procedimentos analíticos limpos em sistemas de análises em fluxo para determinação de espécies de interesse ambiental." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-20102006-084230/.
Full textAbstract:
A química limpa tem como principal objetivo o desenvolvimento e a implementação de processos e produtos químicos para reduzir ou eliminar o uso ou a geração de substâncias nocivas à saúde humana e ao meio ambiente. Neste trabalho, foram desenvolvidos procedimentos analíticos limpos para a determinação de nitrato e nitrito em águas naturais e para o tratamento dos resíduos gerados na determinação espectrofotométrica de nitrito e fenóis. Para tanto, foram exploradas as principais estratégias empregadas em química limpa: substituição dos reagentes tóxicos, minimização do consumo dos reagentes e dos resíduos gerados e tratamento desses resíduos. O procedimento analítico limpo para a determinação de nitrato em águas naturais foi baseado em medidas diretas no ultravioleta, após separação de nitrato dos interferentes utilizando um sistema de análises em fluxo com coluna de resina aniônica. O método desenvolvido emprega um único reagente (HClO4) em quantidades mínimas (18 µL/determinação) e permite a determinação de nitrato entre 0,50 e 25,0 mg L-1, sem interferência de ácido húmico, NO2-, PO43-, Cl-, SO42- e ferro(III) nas quantidades usuais em águas naturais. A freqüência de amostragem e o coeficiente de variação (n = 20) foram estimados em 17 determinações h-1 e 0,7%, respectivamente. Os resultados obtidos para amostras de águas de diferentes procedências foram concordantes com o método de referência (redução a nitrito por limalhas de cádmio cobreado seguida por reação de diazo-acoplamento) a nível de confiança de 95%. O tratamento do resíduo gerado na determinação de nitrito, empregando irradiação (UV) na presença do reagente de Fenton (80 mmol/L H2O2 e 1 mmol/L Fe2+), promoveu completa descoloração do resíduo com diminuição de ca. 87% na concentração de carbono orgânico total. A fotodegradação também foi aplicada no tratamento do resíduo gerado na determinação de fenóis totais com 4-aminoantipirina. A degradação ocorreu na presença de H2O2 e irradiação (UV). A completa supressão da absorção de radiação pela 4-aminoantipirina foi observada após 30 min de recirculação da solução no foto-reator, à vazão de 4 mL/min. O procedimento analítico para a determinação de nitrito foi baseado em sistema de análises em fluxo com multicomutação empregando mini-bombas solenóides para o gerenciamento das soluções. O sistema foi acoplado a um foto-reator para a degradação em linha dos resíduos gerados. O método desenvolvido minimiza as quantidades de reagentes (0,6 mg sulfanilamida e 0,03 mg N-naftil-etilenodiamina por determinação) e permite a determinação de nitrito entre 0,10 e 1,00 mg L-1 (r = 0,998) com sensibilidade comparável à alcançada no procedimento com adição contínua de reagentes. O limite de detecção (99,7% de confiança), coeficiente de variação (n = 20) e freqüência de amostragem foram estimados em 17 µg L-1, 2,6% e 80 determinações h-1, respectivamente.Green chemistry has as principal objective the development and implementation of chemical processes and products to minimize or eliminate the use or generation of harmful substances to the human health and the environment. In this work, clean analytical procedures for determination of nitrate and nitrite in natural waters and for the treatment of wastes generated in the spectrophotometric determination of nitrite and phenol were developed. The principal strategies employed in green chemistry were explored to achieve these goals: replacement of the toxic reagents, minimization of reagent consumption and waste generation and waste treatment. The clean analytical procedure for nitrate determination in natural waters was based on the direct spectrophotometric measurement in the ultraviolet, after separation of nitrate from interfering species in a flow-injection system with an anion-exchange resin. The developed method employ only one reagent (HClO4) in minimum amount (18 µL/determination) and can be applied for nitrate determination within 0.50 and 25.0 mg L-1, without interference of humic acid, NO2-, PO43-, Cl-, SO42- and iron(III) in concentrations typically found in natural waters. The sampling rate and the coefficient of variation (n = 20) were estimated as 17 determinations per hour and 0.7%, respectively. Results obtained for natural water samples of different origin were in agreement with the reference method (reduction to nitrite by copperized cadmium filings followed by a diazo-coupling reaction) at the 95% confidence level. The treatment of the waste generated in nitrite determination employing UV irradiation in the presence of Fenton reagent (80 mmol/L H2O2 and 1 mmol/L Fe2+) caused the complete discoloration of the waste and reduced the total organic carbon concentration in 87%. The photodegradation was also applied for the treatment of the waste generated in the determination of total phenols with 4-aminoantipyrine. The degradation occurred in the presence of H2O2 and UV irradiation. Radiation absorption by 4-aminoantipyrine was completely suppressed after 30 min of treatment of solution in the recirculation mode at 4mL/min. The analytical procedure for nitrite determination was based on a flow system with multicommutation employing solenoid micro-pumps for the solution handling. The developed method minimizes the reagent amounts (0.6 mg sulfanilamide and 0.03 mg N-(1-Naphthyl)-ethylene-diamine per determination) and can be applied for nitrite determination within 0.10 and 1.00 mg L-1 (r = 0.998) with sensitivity comparable to the achieved in the procedure with continuous reagent addition. The detection limit (99.7% of confidence), coefficient of variation (n = 20) and sampling rate were estimated as 17 µg L-1, 2.6% and 80 determinations per hour, respectively.
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Ferreira, Paulo Eduardo Gomes. "Efeito de um programa pré-operatório de fortalecimento supervisionado da musculatura inspiratória na evolução hospitalar de pacientes submetidos a operações cardíacas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/17/17137/tde-05042013-230022/.
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Introdução: A disfunção respiratória é uma das complicações mais frequentes após operações cardíacas. Vários fatores contribuem para que as disfunções respiratórias ocorram, dentre eles está a disfunção da musculatura inspiratória que, por sua vez, pode ser multifatorial. Objetivo: O condicionamento da musculatura inspiratória no período pré-operatório poderia ajudar a reduzir a incidência de complicações respiratórias no pós-operatório de operações cardíacas. Métodos: No presente trabalho 21 pacientes voluntários, de ambos os sexos, com idade mínima de 50 anos, com fraqueza de musculatura inspiratória e candidatos à operação de revascularização cirúrgica do miocárdio e/ou operação valvar cardíaca no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto-USP foram distribuídos aleatoriamente em 2 grupos. Em um grupo, 10 pacientes foram submetidos a um período mínimo de 9 dias de treinamento da musculatura inspiratória utilizando um incentivador respiratório marca Threshold® IMT (Respironics, Cedar Grove, NJ, EUA), com carga de 40, 60 e 80% da pressão inspiratória máxima. Os outros 11 pacientes receberam apenas orientações gerais, sem treinamento objetivo da musculatura respiratória. Comparamos os valores espirométricos antes e após o treinamento dentro de cada grupo. A evolução da pressão inspiratória máxima, da pressão expiratória máxima e da gasometria arterial de ambos os grupos, antes e após o treinamento, bem como a sua evolução temporal no pós-operatório, além dos valores de nitrito/nitrato no condensado do exalado pulmonar. Comparamos também a evolução clínica de ambos os grupos. Resultados: Observamos que o treinamento causou elevação significativa do pico de fluxo expiratório (p=0,028) e diminuição nos valores de nitrito/nitrato no condensado do exalado pulmonar (p=0,05) e redução das complicações pós operatórias (p=0,057), sendo as duas últimas não significativas. Todavia, não houve diferença na evolução gasométrica e nem da pressão inspiratória máxima ou da pressão expiratória máxima entre ambos os grupos. Conclusão: O treinamento da musculatura respiratória inspiratória em pacientes internados, além de factível e seguro, resulta em maior fortalecimento dessa musculatura, reduz a morbidade pós-operatória e os níveis de nitrito/nitrato no condensado do exalado pulmonarIntroduction: Respiratory dysfunction is one of the most common complications after cardiac operations. Several factors contribute to respiratory dysfunctions that occur among them is inspiratory muscle dysfunction that, in turn, may be multifactorial. Objective: The conditioning of inspiratory muscles on preoperative could help reduce the incidence of respiratory complications in the postoperative period of cardiac operations. Methods: In this study 21 patients volunteers of both sexes, aged 50 years, with weakness of inspiratory muscles and candidate operation of CABG and / or heart valve surgery at the Hospital of the Medical College of Ribeirão Preto-USP were randomized into 2 groups. In one group, 10 patients underwent a minimum of 9 days of inspiratory muscle training using an incentive spirometry \"Threshold® IMT\" (Respironics, Cedar Grove, NJ, USA) with a load of 40, 60 and 80% of maximal inspiratory pressure. The other 11 patients received only general guidelines without respiratory muscle training goal. We compared spirometric values before and after training within each group. The evolution of maximal inspiratory pressure, maximal expiratory pressure and arterial blood gas analysis of both groups before and after training, as well as its temporal evolution postoperatively, and the values of nitrite / nitrate in exhaled breath condensate. We also compared the clinical outcomes in both groups. Results: We observed that the training caused significant peak expiratory flow (p=0,028) and decrease in nitrite/nitrate in exhaled breath condensate (p=0,05) and reduction of postoperative complications (p=0,057), the last two being non-significant. However, there was no difference in blood gas evolution nor maximal inspiratory pressure and maximal expiratory pressure between both groups. Conclusion: The inspiratory muscle training in patients hospitalized, and feasible and safe, results in further strengthening these muscles, reduces postoperative morbidity and levels of nitrite / nitrate in exhaled breath condensate
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Bernardo, Patrícia Ramalheiro. "Caracterização de perigos químicos em enchidos curados tradicionais : nitrosaminas e seus precursores." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2021. http://hdl.handle.net/10400.5/21238.
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Dissertação de Mestrado em Segurança AlimentarO salpicão é um enchido curado tradicional português, que pertence a um vasto grupo de produtos cárneos. Para além de representarem parte da dieta mediterrânica, estes produtos são importantes para as economias rurais e para a preservação da herança. No entanto, em 2015, a IARC avaliou a carcinogenicidade do consumo de carne processada. Como resultado, a carne processada foi classificada como carcinogénica para humanos (Grupo 1), com base em evidência suficiente de que o consumo de carne processada causa cancro colorretal. As N-nitrosaminas inserem-se no grupo das substâncias responsáveis por este efeito carcinogénico. Desta forma, é importante saber se estes compostos estão presentes nos produtos cárneos, particularmente no salpicão. Mais ainda, é importante perceber se estão reunidas as condições para a sua formação, nomeadamente precursores e ambiente ácido. Por estes motivos, analisaram-se amostras de salpicão, de três unidades fabris distintas, quanto aos teores de nitratos, nitritos, aminas secundárias e N-nitrosaminas. Também o pH das amostras foi analisado. As análises químicas foram efetuadas nos seguintes pontos temporais: carne (T0), pré-enchimento (T1), meia cura (T2), produto final (T3), meio do prazo de validade (T4) e final do prazo de validade (T5). Os valores de pH variaram entre 5,6 e 5,8 na carne (T0) e mantiveram-se dentro da gama esperada para produtos fermentados. Não se detetaram nitratos (acima do Limite de Quantificação). Quanto à determinação de nitrito residual, apenas se detetaram (acima do Limite de Quantificação) nas amostras da unidade fabril C, mas sempre em teores muito inferiores ao permitido na legislação da EU (100 mg NaNO2/kg). Não se detetaram aminas secundárias nas amostras da unidade fabril B. Detetaram-se aminas secundárias em algumas amostras da unidade fabril A (T1 e T5) e da unidade fabril C (T0, T1 e T5), sendo que os valores médios mais elevados foram: 7,4 mg de Piperdina/kg, 11,0 mg de Di-n-propilamina/kg, 20,9 mg de Pirrolidina/kg, 22,6 mg de Morfolina/kg e 26,2 mg de Dimetilamina/kg. Não se detetaram nitrosaminas nas amostras analisadas. Apesar de existir uma válida preocupação em torno das N-nitrosaminas, estes compostos não foram detetados nos produtos em estudo, nem os seus precursores em concentrações suficientes, para a sua formação. É necessário continuar a estudar este assunto para que se consiga compreender a relação entre o consumo de diferentes tipos de carne processada e o verdadeiro risco para a saúde do Homem.
ABSTRACT - Characterization of chemical hazards in traditional cured meat sausages: nitrosamines and precursors - “Salpicão” is a traditional Portuguese cured sausage, and it belongs to a wide group of meat products. These products not only represent part of the Mediterranean diet, but also have great value for the economy of rural areas and for the preservation of heritage. However, in 2015, IARC has evaluated the carcinogenicity associated to the consumption of processed meat. As a result, processed meat was classified as carcinogenic to humans (Group 1), based on sufficient evidence that the consumption of processed meat causes colorectal cancer. N-nitrosamines are among the responsible substances for the assessed carcinogenic effect. Therefore, there is a need to understand if these compounds are present in meat products, particularly in “salpicão”. Moreover, it is also important to know if the combination of precursors and acidic environment are gathered, to generate N-nitrosamines. For this purpose, samples of “salpicão”, from three distinct factories, were analysed for the quantification of nitrate, nitrite, secondary amines, and N-nitrosamines levels. The pH levels were also evaluated. The chemical analyses and pH evaluation were performed at the following time points: raw meat (T0), before stuffing (T1), middle of curing process (T2), finished product (T3), middle of shelf-life (T4), and end of shelf-life (T5). The pH values of all meat samples ranged between 5,6 and 5,8 and remained within the expected for fermented products. No residual nitrate levels were found to be above the Limit of Quantification. As for residual nitrite levels, those were only detected (above Limit of Quantification) in the samples from factory C, but always considerably under the legal EU limit (100 mg NaNO2/kg). No secondary amines were detected in the samples from factory B. Secondary amines were detected in few samples of the factory A (T1 and T5) and factory C (T0, T1 and T5), with the highest mean values of 7,4 mg of Piperdine/kg, 11,0 mg of Dipropylamine/kg, 20,9 mg of Pyrrolidine/kg, 22,6 mg of Morpholine/kg and 26,2 mg of Dimethylamine/kg. No nitrosamines were detected in the analysed samples. Although nitrosamines may be substances of great concern, they were not found in these meat products, nor their precursors, in sufficient concentrations. Further studies are required to fully understand the link between the consumption of different kinds of processed meat and the actual risk that they represent to human health.
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Ré, Ana de Almeida. "Aplicação de infusões de ervas aromáticas para substituição de aditivos químicos num modelo de carne fermentado." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2020. http://hdl.handle.net/10400.5/20364.
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Dissertação de Mestrado Integrado em Medicina VeterináriaAtualmente, existe uma procura crescente por conservantes naturais, sobretudo de origem vegetal, para reduzir o conteúdo de nitrito e/ou nitrato (aditivos químicos) em produtos curados à base de carne. Com este trabalho pretendeu-se estudar formas de substituir o uso destes aditivos químicos por infusões de quatro ervas aromáticas (Manjericão Rubra, Tomilho Limão, Orégãos vulgar e Sálvia Ananás), como fonte natural de nitrato, avaliando a evolução da microbiota tecnológica, características físico-químicas e sensoriais (baseado numa escala Just about right), num modelo cárneo armazenado em refrigeração durante quatro dias. Foram realizadas seis formulações, com diferentes concentrações de nitrato de sódio (mg) por quilograma de produto cárneo, correspondentes a: (C) Controlo com 0 ppm; (T1) Manjericão rubra com 70 ppm; (T2) Tomilho limão com 70 ppm; (T3) Manjericão rubra com 100 ppm; (T4) Sálvia ananás com 100 ppm; (T5) Orégãos com 100 ppm. Os modelos cárneos foram analisados realizando-se contagens de Aeróbios totais a 30 ºC, Enterobacteriaceae, Bactérias Ácido Lácticas (BAL) e Staphylococcus coagulase negativa (SCN). Foram ainda determinados os teores de nitratos, nitritos, cloretos, a cor e o pH. As infusões com sálvia ananás mostraram ter um maior conteúdo de nitrato (63.124 mg/100ml) em comparação com infusões de tomilho limão e orégãos. O modelo cárneo T4 apresentou uma maior quantidade de nitratos (média 16.91 mg/kg). Este produto modelo após um período de 2 para 4 dias de armazenamento a 4 ºC, apresentou valores de nitrito de 3.93 mg/kg, onde se observou que a cor após cozedura teve um aumento da coordenada a* no dia 4, demonstrando uma cor mais rosada/avermelhada, indicativo do desenvolvimento do nitrosohemocromogénio. Além disso na caracterização sensorial do produto modelo não se notou nenhum aroma a ervas ou especiarias, exibindo sabores e cheiros neutros. Estes resultados indicam que os ingredientes naturais, como a infusão de sálvia ananás, podem ser possivelmente utilizados como alternativa a aditivos químicos na cura tradicional. Contudo, é necessária mais investigação para avaliar o impacto sensorial e microbiológico deste ingrediente quando utilizado em produtos curados à base de carne com novas formulações e com a adição de novos condimentos.
ABSTRACT - Application of aromatic plants infusions to replace chemical additives in a fermented meat model - Currently, there is an increasing demand for natural preservatives, mainly of vegetable origin, to reduce the content of nitrite and/or nitrate (chemical additives) in cured meat products. This work aimed to study ways to replace the use of these chemical additives by infusions of four aromatic plants (Red Basil, Lemon Thyme, Common Oregano and Pineapple Sage), as a natural source of nitrate, evaluating the evolution of technological microbiota, physical-chemical and sensory characteristics (based on a Just about right scale), in a meat model stored in refrigeration for four days. Six formulations were performed, with different concentrations of sodium nitrate (mg) per kilogram of meat product, corresponding to (C) 0 ppm control; (T1) 70 ppm red basil; (T2) 70 ppm lemon thyme; (T3) 100 ppm red basil; (T4) 100 ppm pineapple sage; (T5) 100 ppm common oregano. The meat models were analysed by performing total Aerobic counts at 30 ºC, Enterobacteriaceae, Lactic Acid Bacteria (BAL) and Staphylococcus coagulase negative (SCN). The levels of nitrates, nitrites, chlorides, colour and pH were also determined. Pineapple Sage infusions showed a higher nitrate content (63,124 mg/100ml) compared to lemon thyme and common oregano infusions. The T4 meat model showed a higher nitrate content (mean 16.91 mg/kg). This model product after a period of 2 to 4 days of storage at 4 ºC, showed nitrite values of 3.93 mg/kg, where it was observed that the colour after cooking had an increase of the a* coordinate on day 4, showing a pinker/redder colour, indicative of the development of nitrosohemochromogen. In addition, the sensory characterization of the model product did not show any herbs or spices aroma, presenting neutral flavours and smells. These results indicate that natural ingredients, such as pineapple sage infusion, can possibly be used as an alternative to chemical additives in traditional curing. However, further research is needed to assess the sensory and microbiological impact of this ingredient when used in cured meat products with new formulations and the addition of new condiments.
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Books on the topic "Nitrity"
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Loscalzo, Joseph, and Nathan S. Bryan. Nitrite and nitrate in human health and disease. New York: Humana Press, 2011.
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International Agency for Research on Cancer and World Health Organization, eds. Ingested nitrate and nitrite, and cyanobacterial peptide toxins. Lyon, France: International Agency for Research on Cancer, 2010.
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Bryan, Nathan S., and Joseph Loscalzo, eds. Nitrite and Nitrate in Human Health and Disease. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-60761-616-0.
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Bryan, Nathan S., and Joseph Loscalzo, eds. Nitrite and Nitrate in Human Health and Disease. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-46189-2.
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Mitchell, Garry John. Biochemical studies of nitrate and nitrite reduction in sulphate-reducing bacteria. Birmingham: University of Birmingham, 1985.
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Feng, Yu. Transport of nitrate and nitrite across the Escherichia Coli cytoplasmic membrane. Birmingham: University of Birmingham, 2003.
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Antweiler, Ronald C. Automated, colorimetric methods for determination of nitrate plus nitrite, nitrite, ammonium and orthophosphate ions in natural water samples. Denver, Colo: U.S. Geological Survey, 1996.
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Willis, R. B. Automated method for determining nitrate and nitrite in water and soil extracts. S.l: s.n, 1987.
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Clegg, Stephanie Jane. Nitrate and nitrite transport across the cytoplasmic membrane of Escherichia coli K-12. Birmingham: University of Birmingham, 2002.
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Peake, Eric. Nitric acid, peroxyacetyl nitrate (PAN), and particulate nitrate in the atmosphere of the City of Edmonton. Edmonton: Research Management Division, Alberta Environment, 1985.
Find full textBook chapters on the topic "Nitrity"
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Lundberg, Jon O., Eddie Weitzberg, Sruti Shiva, and Mark T. Gladwin. "The Nitrate–Nitrite–Nitric Oxide Pathway in Mammals." In Nitrite and Nitrate in Human Health and Disease, 21–48. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-60761-616-0_3.
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Ware, George W. "Nitrate and Nitrite." In Reviews of Environmental Contamination and Toxicology, 117–30. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4684-7083-3_10.
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Makkar, Harinder P. S., P. Siddhuraju, and Klaus Becker. "Nitrate and Nitrite." In Plant Secondary Metabolites, 33–39. Totowa, NJ: Humana Press, 2007. http://dx.doi.org/10.1007/978-1-59745-425-4_7.
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Hotchkiss, Joseph H., Michael A. Helser, Chris M. Maragos, and Yin-Ming Weng. "Nitrate, Nitrite, andN-Nitroso Compounds." In ACS Symposium Series, 400–418. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0484.ch033.
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Klurfeld, David M. "Nitrite and Nitrate in Cancer." In Nitrite and Nitrate in Human Health and Disease, 263–78. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-60761-616-0_16.
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Klurfield, David M. "Nitrite and Nitrate in Cancer." In Nitrite and Nitrate in Human Health and Disease, 311–23. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-46189-2_21.
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Holtmeier, H. J. "Gefährdung durch Nitrat und Nitrit." In Gesunde Ernährung von Kindern und Jugendlichen, 176–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-79300-4_18.
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Totzeck, Matthias, Ulrike B. Hendgen-Cotta, and Tienush Rassaf. "Nitrite-Nitric Oxide Signaling and Cardioprotection." In Advances in Experimental Medicine and Biology, 335–46. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-55330-6_18.
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Wany, Aakanksha, Pradeep Kumar Pathak, and Kapuganti Jagadis Gupta. "Methods for Measuring Nitrate Reductase, Nitrite Levels, and Nitric Oxide from Plant Tissues." In Nitrogen Metabolism in Plants, 15–26. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9790-9_2.
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Geng, Yong-Jian. "The Nitrate–Nitrite–Nitric Oxide Pathway in Traditional Herbal Medicine for Heart Disease." In Nitrite and Nitrate in Human Health and Disease, 247–61. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-60761-616-0_15.
Full textConference papers on the topic "Nitrity"
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Shibuya, M., Y. Suzuki, H. Shimizu, M. Inoue, H. Kaneki, N. Moriya, E. Ochi, and H. Aoyagi. "Study on Reduction of Liquid Waste From Reprocessing Plant by Electrolysis Process." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1298.
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Abstract The reduction of radioactive waste volume is an important issue for the management of the nuclear fuel cycle. The purpose of this study is to create a technique to drastically reduce low-level liquid waste generated by a spent fuel reprocessing plant employing PUREX technology. In the PUREX plant, NOx gas is used as an oxidizing reagent for adjustment of the Pu valence in the Pu purification stage. The spent NOx gas is recovered as nitric acid and a certain amount of recovered nitric acid becomes low-level waste (LLW). As NOx gas is produced by the chemical reaction of nitric acid and sodium nitrite, a considerable quantity of non-radioactive sodium nitrate solution is discharged. From the standpoint of the impact on the environment, this discharge must be reduced. The objective of this research is to develop an electrolysis process by which NOx gas is directly produced from recovered nitric acid. Using this technology, the low-level sodium nitrate waste can be reduced and the nonradioactive sodium nitrate waste from the present NOx production process can be entirely eliminated. The study was performed in the following two steps: Phase 1: Fundamental research; Phase 2: Engineering study. Fundamental research: A study on the conditions of nitric acid decomposition by electrolysis was performed. The composition of NO and NO2 and its quantity are determined by electrolyte concentration, cathode material and current density. Catholyte reduced electrochemically is in a state of chemical equilibrium expressed by NO, NO2 (N2O4), HNO2, HNO3 and H2O. Nitric acid concentration, temperature and partial pressure of NOx are important process parameters since NOx generation current efficiency and NOx gas composition are dependent on a chemical equilibrium. Engineering study: The pilot plant was designed and constructed. The process configuration of the pilot plant is the same as that of the anticipated actual plant and its NOx generation capacity is one eighth of the actual plant. The plant mainly consists of electrolysis unit, NOx compression and storage unit, sodium nitrite oxidation unit, nitric acid distillation unit, and NOx recovery and off-gas treatment unit. NOx gas and HNO2 are generated as a result of nitric acid reduction in the electrolysis unit. NOx gas is transported under negative pressure to the compression/storage unit by a compressor and is stored in tanks under high pressure. After adjustment of gas composition by O2 supply, NOx gas is fed to the user process in the case of an actual plant. In the pilot test plant, NOx gas is transported to the nitric acid recovery step, in which NOx gas is recovered as nitric acid and reused in the pilot plant. As a result of operation of the pilot plant, the process performance, equipment performance, and long-term operation stability were proven. It was confirmed through the pilot plant operation that this technology was immediately applicable to a PUREX reprocessing plant.
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Goreacioc, Tatiana, Maria Sandu, Raisa Nastas, and Anatolie Tarita. "Poluarea apelor de suprafata şi subterane cu compuşi ai azotului." In Impactul antropic asupra calitatii mediului. Institute of Ecology and Geography, Republic of Moldova, 2019. http://dx.doi.org/10.53380/9789975330800.21.
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In this paper the situation of pollution with nitrogen compounds both in the EU member states and in the Republic of Moldova was analyzed. Also, the existing methods of determination of nitrate ions are analyzed and the necessity of elaborating the method for determination of the nitrate ions in the presence of nitrite ions.
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Bradshaw, Robert W., Joseph G. Cordaro, and Nathan P. Siegel. "Molten Nitrate Salt Development for Thermal Energy Storage in Parabolic Trough Solar Power Systems." In ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90140.
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Multi-component molten salts have been formulated recently that may enhance thermal energy storage for parabolic trough solar power plants. This paper presents further developments regarding molten salt mixtures consisting of common alkali nitrates and either alkaline earth nitrates or alkali nitrite salts that have advantageous properties for applications as heat transfer fluids in parabolic trough systems. We report results for formulations of inorganic molten salt mixtures that display freeze-onset temperatures below 100°C. In addition to phasechange behavior, several properties of these molten salts that significantly affect their suitability as thermal energy storage fluids were evaluated, including chemical stability and viscosity. The nitrate-based molten salts have demonstrated chemical stability in the presence of air up to 500°C. The capability to operate at temperatures up to 500°C may allow an increase in maximum temperature operating capability vs. organic fluids in existing trough systems and will enable increased power cycle efficiency. Experimental measurements of viscosity were performed from near the freeze-onset temperature to about 200°C. Viscosities can exceed 100 cP near the freezing temperature but are 4 to 5 cP in the anticipated operating temperature range. Experimental measurements of density, thermal conductivity and heat capacity are in progress and will be reported at the meeting. Corrosion tests were conducted for several thousand hours at 500°C with stainless steels and at 350°C for carbon and chromium-molybdenum steels. Examination of the specimens demonstrated good compatibility of these materials with the molten nitrate salt mixtures. Laboratory studies were conducted to identify mixtures of nitrate and nitrite (NO2−) salts as additional candidates for a low-melting heat transfer fluid. Mixtures in which the cations were potassium, sodium and lithium, in various proportions, demonstrated freezing points as low as 70°C for a particular nitrate/nitrite anion composition. Development has emphasized mixtures that minimize lithium content in order to reduce the cost as the lithium salt is the most expensive constituent. Work is in progress to explore the phase diagram of the 1:1 mol ratio of nitrate/nitrite and to evaluate physical properties such as viscosity, density and thermal conductivity. Results to date indicate that the viscosity of these mixtures is considerably less than nitrate-only melts, which necessarily contain calcium cations to suppress freezing to similarly low temperatures.
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Martin, Richard Lloyd. "Corrosion Consequences of Nitrate/Nitrite Additions to Oilfield Brines." In SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 2008. http://dx.doi.org/10.2118/114923-ms.
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Li, Wei, Xiao Liang, Qiangliang Zhao, Jianguo Lin, and Deqiang Yin. "Effects of Organic Carbon and Nitrite on Simultaneous Organic Carbon, Sulfide, Nitrate and Nitrite Removal." In 2010 4th International Conference on Bioinformatics and Biomedical Engineering (iCBBE). IEEE, 2010. http://dx.doi.org/10.1109/icbbe.2010.5515542.
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Fiore, Marina, Massimo Brenci, and Janusz Kozlowski. "Fiber optic sensor to detect nitrite and nitrate in water." In Environmental Sensing III, edited by Robert A. Lieberman. SPIE, 1997. http://dx.doi.org/10.1117/12.276145.
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Meguro, Yoshihiro, Atsushi Kato, Yoko Watanabe, and Kuniaki Takahashi. "Separation and Recovery of Sodium Nitrate From Low-Level Radioactive Liquid Waste by Electrodialysis." In ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2010. http://dx.doi.org/10.1115/icem2010-40082.
Full textAbstract:
An advanced method, in which electrodialysis separation of sodium nitrate and decomposition of nitrate ion are combined, has been developed to remove nitrate ion from low-level radioactive liquid wastes including nitrate salts of high concentration. In the electrodialysis separation, the sodium nitrate was recovered as nitric acid and sodium hydroxide. When they are reused, it is necessary to reduce the quantity of impurities getting mixed with them from the waste fluid as much as possible. In this study, therefore, a cation exchange membrane with permselectivity for sodium ion and an anion exchange membrane with permselectivity for monovalent anion were employed. Using these membranes sodium and nitrate ions were effectively removed form a sodium nitrate solution of high concentration. And also it was confirmed that sodium ion was successfully separated from cesium and strontium ions and that nitrate ion was separated from sulfate and phosphate ions.
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Dabužinskaitė, Ginta, Ilona Kerienė, and Aušra Mažeikienė. "ŠIAURĖS LIETUVOS ŠACHTINIŲ ŠULINIŲ VANDENS KOKYBĖS TYRIMAS." In 22-oji jaunųjų mokslininkų konferencijos „Mokslas – Lietuvos ateitis“ teminė konferencija APLINKOS APSAUGOS INŽINERIJA. Vilnius Gediminas Technical University, 2020. http://dx.doi.org/10.3846/aainz.2019.005.
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Lietuvoje apie 700 tūkst. gyventojų vis dar iš šachtinių šulinių tebevartoja geriamąjį vandenį, kurio kokybė neužtikrina saugaus jo vartojimo. 2017–2018 metais tirta Šiaulių miesto, rajono ir apskrities šachtinių šulinių vandens kokybė. Nustatytos geležies, fosfatų, fluoridų, chloridų, bromidų, nitritų, nitratų, sulfatų jonų koncentracijos ir bendrasis vandens kietis. Nustatyta, kad 60 % tirtųjų Šiaulių miesto ir apskrities šachtinių šulinių vandens kokybė pagal nitratų ir geležies jonų koncentracijas neatitinka HN 24:2017 higienos normos reikalavimų. Didžiausia geležies jonų koncentracija nustatyta Šiaulių rajone, sodų bendrijos šulinio vandenyje (214 μg/l), kur iš viso 10 % tirtųjų mėginių viršijo HN 24:2017 higienos normos reikalavimus. Šiaulių miesto gyventojai, vartojantys vandenį iš šachtinių šulinių, turėtų atkreipti dėmesį į vandens kokybę dėl didelės (daugiau, kaip 300 mg/l) nitratų jonų koncentracijos, iki 6 kartų viršijančios HN 24:2017 higienos normos reikalavimus. Gyventojams rekomenduojama aktyviau jungtis prie centralizuotų vandentiekio tinklų arba periodiškai tikrinti geriamojo vandens kokybę.
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Voordouw, G. "Oil Field Biotechnology: Should We Use Nitrate or Nitrite to Remediate Souring." In Canadian International Petroleum Conference. Petroleum Society of Canada, 2003. http://dx.doi.org/10.2118/2003-144-ea.
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Coombe, D., C. Hubert, and G. Voordou. "Mechanistic Modelling of H2S Souring Treatments by Application of Nitrate or Nitrite." In Canadian International Petroleum Conference. Petroleum Society of Canada, 2004. http://dx.doi.org/10.2118/2004-292.
Full textReports on the topic "Nitrity"
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Hobbs, D. T. Evaluation of nitrate and nitrite destruction/separation technologies. Office of Scientific and Technical Information (OSTI), August 1997. http://dx.doi.org/10.2172/573703.
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Tsybekmitova, G. Ts, L. D. Radnaeva, N. A. Tashlykova, V. G. Shiretorova, A. K. Tulokhonov, B. B. Bazarova, and M. O. Matveeva. THE EFFECT OF CLIMATIC SHIFTS ON BIODIVERSITY OF PHYTOCENOSIS: LAKE ARAKHLEY (EASTERN SIBERIA, RUSSIA). DOICODE, 2020. http://dx.doi.org/10.18411/0973-7308-2020-35-3-77-90.
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Lake Arakhley is located within the Lake Baikal basin in Eastern Siberia, Russia. The area is characterized by continental subarctic climate with considerate diurnal temperature range, long cold dry winters and short hot summers with more precipitation occurring during the latter half of the summer. Climatic shifts in high water years and low water years result in morphometric changes in the lake and in the chemical and physical parameters of the ecosystem. During low water years, concentrations of ammonium nitrogen and nitrite nitrogen are decreased, whereas nitrate concentration increases. High water years feature average concentrations of ammonium ions 1.5–2 times higher than the values of recent dry years. Redundancy analysis (RDA) of abiotic factors and biotic community indicated that the community structure shows the greatest correlation with physical and chemical parameters of water and biogenic elements (nitrites, ammonium, phosphates) along the first axis, and with the lake depth and transparency along the second axis. Changes in abiotic factors induce functioning and formation of characteristic communities of the primary producers in the trophic structure of the ecosystem. During low water years, with increased level of autochthonous organic matter, Lindavia comta dominance is observed, while during high water years, with increased allochthonous organic matter Asterionella formosa appeared as dominant. Currently, during low water years, the hydrophytes community is monodominant and composed of Ceratophyllum demersum. Meanwhile, such species indicating eutrophic conditions as Myriophyllum sibiricum, Potamogeton pectinatus are found in the lake vegetation.
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Spencer, B. B. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO. Office of Scientific and Technical Information (OSTI), August 1995. http://dx.doi.org/10.2172/110663.
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Congdon, J. W. Effect of Nitrite/Nitrate concentrations on Corrosivity of Washed Precipitate. Office of Scientific and Technical Information (OSTI), March 2001. http://dx.doi.org/10.2172/781032.
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Burger, L. L., and R. D. Scheele. The reactivity of cesium nickel ferrocyanide towards nitrate and nitrite salts. Office of Scientific and Technical Information (OSTI), September 1991. http://dx.doi.org/10.2172/5293537.
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McQuaid, Michael J., and Gregory W. Drake. Property Predictions for Nitrate Salts with Nitroxy-Functionalized Cations. Fort Belvoir, VA: Defense Technical Information Center, May 2011. http://dx.doi.org/10.21236/ada550658.
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Mickalonis, J. I. Corrosion of steel in simulated waste containing different nitrate and nitrite concentrations. Office of Scientific and Technical Information (OSTI), July 1993. http://dx.doi.org/10.2172/10177023.
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Sadergaski, Luke, and Travis Hager. Measuring Hydroxylammonium, Nitrate and Nitrite Concentration with Raman spectroscopy for 238Pu Supply Program. Office of Scientific and Technical Information (OSTI), August 2021. http://dx.doi.org/10.2172/1819552.
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Schrader, Kohl D., Joseph C. Cordray, Joseph G. Sebranek, James S. Dickson, and Aubrey F. Mendonca. Control of Listeria monocytogenes on No-Nitrate-or-Nitrite-Added (Natural or Organic) Frankfurters. Ames (Iowa): Iowa State University, January 2009. http://dx.doi.org/10.31274/ans_air-180814-653.
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Metcalf, S. G. Reverse polarity capillary zone electrophoresis analysis of nitrate and nitrite in natural water samples. Office of Scientific and Technical Information (OSTI), June 1998. http://dx.doi.org/10.2172/16960.
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