Academic literature on the topic 'Medium-weight molecules'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Medium-weight molecules.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Medium-weight molecules"
1
HIGASHIMURA, Toshinobu. "Medium-Molecular Weight Molecules: A New Perspective in Polymer Science." Kobunshi 46, no. 10 (1997): 737. http://dx.doi.org/10.1295/kobunshi.46.737.
Full text
2
Chow, B. P. C., E. A. Shaffer, and H. G. Parsons. "Absorption of triglycerides in the absence of lipase." Canadian Journal of Physiology and Pharmacology 68, no. 4 (1990): 519–23. http://dx.doi.org/10.1139/y90-074.
Full textAbstract:
Medium chain triglycerides are considered to be readily absorbed intact in the absence of pancreatic lipase, unlike long chain triglycerides. Commercial medium chain triglyceride oils comprise various medium chain fatty acids from 6 to 12 carbons in length resulting in triglyceride molecules of different sizes and molecular weights. The effect of molecular weight and hence fatty acid chain length on the efficiency of intact medium chain triglyceride absorption is unknown. Therefore, this study measured, using a single-pass marker perfusion technique, intestinal jejunum absorption of five medium chain and one long chain triglycerides in anesthetized Sprague–Dawley rats. The molecular weights of the five medium chain triglycerides were 470.7, 498.8, 526.8, 554.9, 639.0, and the long chain triglyceride, 885.4. Residual luminal pancreatic lipase was removed prior to lipid perfusion. This study demonstrated that medium chain triglycerides were absorbed in the absence of lipase whereas long chain triglyceride was not. There was no significant variation in the absorption of the five different medium chain triglycerides perfused. The molecular weight of the medium chain triglyceride did not affect its intact absorption by the small intestine.Key words: triglycerides, intestinal absorption, molecular weight, pancreatic lipase, fat.
3
Nicastro, Gloria, Louise Mary Black, Paolo Ravarino, et al. "Controlled Hydrolysis of Odorants Schiff Bases in Low-Molecular-Weight Gels." International Journal of Molecular Sciences 23, no. 6 (2022): 3105. http://dx.doi.org/10.3390/ijms23063105.
Full textAbstract:
Imines or Schiff bases (SB) are formed by the condensation of an aldehyde or a ketone with a primary amine, with the removal of a water molecule. Schiff bases are central molecules in several biological processes for their ability to form and cleave by small variation of the medium. We report here the controlled hydrolysis of four SBs that may be applied in the fragrance industry, as they are profragrances all containing odorant molecules: methyl anthranilate as primary amine, and four aldehydes (cyclamal, helional, hydroxycitronellal and triplal) that are very volatile odorants. The SB stability was assessed over time by HPLC-MS in neutral or acidic conditions, both in solution and when trapped in low molecular weight gels. Our results demonstrate that it is possible to control the hydrolysis of the Schiff bases in the gel environment, thus tuning the quantity of aldehyde released and the persistency of the fragrance.
4
TAHIR, LUBNA, MUHAMMAD ISHTIAQ ALI, MUHAMMAD ZIA, NAIMA ATIQ, FARIHA HASAN, and SAFIA AHMED. "Production and Characterization of Esterase in Lantinus tigrinus for Degradation of Polystyrene." Polish Journal of Microbiology 62, no. 1 (2013): 101–8. http://dx.doi.org/10.33073/pjm-2013-015.
Full textAbstract:
Polystyrene is considered stable to biological degradation. Lantinus tigrinus isolated from wood sample produced esterase in growth medium under normal conditions. However, acidic medium, 37 degrees C temperature, presence of tween 80; and urea and yeast extract in mineral salt medium enhance the production of esterase and specific activity. Purified esterase was active at broad pH range and 45 degrees C. FTIR analysis confirmed that esterase produced by Lantinus tigrinus effectively degraded polystyrene film and broke macromolecules down to non-toxic molecules. This study concludes that the presence of Lantinus tigrinus at dumping sites can be exploited for waste management containing high molecular weight synthetic polymers.
5
Yamamoto, Mayumi, Yuki Fujimoto, Shino Hayashi, and Seiichi Hashida. "A study of high-, middle- and low-molecular weight adiponectin in urine as a surrogate marker for early diabetic nephropathy using ultrasensitive immune complex transfer enzyme immunoassay." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 55, no. 5 (2018): 525–34. http://dx.doi.org/10.1177/0004563217748681.
Full textAbstract:
Background For the early identification of patients at risk of developing diabetic nephropathy, we have developed an ultrasensitive immune complex transfer enzyme immunoassay to measure adiponectin in urine. Methods We developed immune complex transfer enzyme immunoassay for adiponectin and measured urinary adiponectin from 70 healthy subjects, 35 obese non-diabetic subjects and 20 patients with diabetes. Results The urinary adiponectin concentrations in patients with diabetes (3.3 ± 10.7 ng/mg creatinine) were significantly higher than those in obese subjects (0.54 ± 0.44; P < 0.01) and healthy subjects (0.46 ± 0.42; P < 0.001). The gel filtration elution profile of urine from healthy subjects showed traces of four immunoreactive peaks (high-, medium-, low-molecular weight and monomer molecules), despite the majority of blood adiponectin being high-molecular weight. However, urinary adiponectin molecules were more frequent in low-molecular weight as the estimate glomerular filtration rate decreased. Furthermore, as blood glucose concentrations rose, middle-molecular weight and high-molecular weight increased in urine. Further, urinary adiponectin concentrations correlated with estimate glomerular filtration rate ( r = −0.61, P < 0.001), but not urinary albumin. In addition, our analysis showed a significantly ( P < 0.001) higher value for urinary adiponectin in the G2 stage of chronic kidney disease classification where urinary albumin is not elevated. Conclusion Adiponectin increases in urine as renal function decreases, and urinary adiponectin may be useful as a surrogate marker for diabetic nephropathy risk.
6
Sedláček, Jan, and Jiří Vohlídal. "Controlled and Living Polymerizations Induced with Rhodium Catalysts. A Review." Collection of Czechoslovak Chemical Communications 68, no. 10 (2003): 1745–90. http://dx.doi.org/10.1135/cccc20031745.
Full textAbstract:
In the last fifteen years, a large variety of specialty polymers of diverse chemical structure and functionality have been synthesized with the rhodium-based catalysts. The high tolerance to the reaction medium and functional groups of monomers, as well as ability to control various structure features of the polymer formed are typical properties of these catalysts. In addition, some rhodium catalysts can be anchored to inorganic or organic supports or dissolved in ionic liquids to form heterophase polymerization systems, which opens the way to pure, well-defined polymers free of the catalyst residues, as well as to recycling rhodium catalysts. This review provides a survey on the polymerization reactions induced with rhodium-based catalysts, in which one or more structure attributes of the polymer formed are subject to control. The structure attributes considered are (i) sequential arrangement of monomeric units along polymer chains; (ii) head-tail isomerism of polymer molecules; (iii) configurational structure of polymer molecules; (iv) conformation of polymer molecules; and (v) molecular weight and molecular-weight distribution of the polymer formed. A review with 188 references.
7
Holyavka, M. G., and V. G. Artyukhov. "Optimization of a Method for Ficin Immobilization Using Glutaraldehyde." Biotekhnologiya 36, no. 5 (2020): 81–88. http://dx.doi.org/10.21519/0234-2758-2020-36-5-81-88.
Full textAbstract:
Ficin was covalently immobilized on an acid-soluble matrix of medium (200 kDa) and high molecular weight (350 kDa) chitosans. The enzyme molecules were immobilized in a protein film and copolymerized with glutaraldehyde. The optimal ratio of protein content, total activity and specific activity was observed as a result of ficin covalent immobilization on a matrix of medium-molecular chitosan with 15% glutaraldehyde and high-molecular chitosan with 10% glutaraldehyde. The obtained biocatalysts are promising for industrial applications. ficin, chitosan, glutaraldehyde, covalent immobilization. This work was financially supported by a grant from the President of the Russian Federation for state support to young Russian scientists-doctors of sciences MD-1982.2020.4. Agreement 075-15-2020-325).
8
Stanishevskaya, Olga, Yulia Silyukova, Nikolai Pleshanov, and Anton Kurochkin. "Role of Mono- and Disaccharide Combination in Cryoprotective Medium for Rooster Semen to Ensure Cryoresistance of Spermatozoa." Molecules 26, no. 19 (2021): 5920. http://dx.doi.org/10.3390/molecules26195920.
Full textAbstract:
The combination of saccharides in the composition of a cryopreservation medium may represent a promising method for the preservation of the reproductive cells of male birds. In the current study, cryoprotective media with a combined composition of mono- and di-saccharides were developed. The degree of penetration of reducing saccharide molecules (maltose—Mal20 medium) and non-reducing disaccharide molecules (trehalose—Treh20 medium) from the cryoprotective medium into the cytosol of rooster spermatozoa was studied. LCM control media without disaccharides were used as the control. The number of maltose molecules penetrating from the outside into the cytosol of the spermatozoon was 1.06 × 104, and the number of trehalose molecules was 3.98 × 104. Using a combination of maltose and fructose, the progressive motility of frozen/thawed semen and the fertility rates of eggs were significantly higher ((p < 0.05) 40.2% and 68.5%, respectively) than when using a combination of trehalose and fructose in a cryoprotective diluent (33.4% and 62.4%, respectively). A higher rate of chromatin integrity at the level of 92.4% was obtained when using Treh20 versus 74.5% Mal20 (p < 0.05). Maltose positively affected the preservation of frozen/thawed sperm in the genital tract of hens. On the seventh day from the last insemination when using Mal20, the fertilization of eggs was 42.6% and only 27.3% when using Treh20. Despite the same molecular weight, maltose and trehalose have different physicochemical and biological properties that determine their function and effectiveness as components of cryoprotective media.
9
Pisani, Silvia, Rossella Dorati, Ida Genta, Enrica Chiesa, Tiziana Modena, and Bice Conti. "High Efficiency Vibrational Technology (HEVT) for Cell Encapsulation in Polymeric Microcapsules." Pharmaceutics 12, no. 5 (2020): 469. http://dx.doi.org/10.3390/pharmaceutics12050469.
Full textAbstract:
Poly(methyl-methacrylate) (PMMA) is a biocompatible and non-biodegradable polymer widely used as biomedical material. PMMA microcapsules with suitable dimension and porosity range are proposed to encapsulate live cells useful for tissue regeneration purposes. The aim of this work was to evaluate the feasibility of producing cell-loaded PMMA microcapsules through “high efficiency vibrational technology” (HEVT). Preliminary studies were conducted to set up the process parameters for PMMA microcapsules production and human dermal fibroblast, used as cell model, were encapsulated in shell/core microcapsules. Microcapsules morphometric analysis through optical microscope and scanning electron microscopy highlighted that uniform microcapsules of 1.2 mm with circular surface pores were obtained by HEVT. Best process conditions used were as follows: frequency of 200 Hz, voltage of 750 V, flow rate of core solution of 10 mL/min, and flow rate of shell solution of 0.5 bar. Microcapsule membrane allowed permeation of molecules with low and medium molecular weight up to 5900 Da and prevented diffusion of high molecular weight molecules (11,000 Da). The yield of the process was about 50% and cell encapsulation efficiency was 27% on total amount. The cell survived and growth up to 72 h incubation in simulated physiologic medium was observed.
10
Ng, Yoke Mooi, Paolo Coghi, Jerome P. L. Ng, Fayaz Ali, Vincent Kam Wai Wong, and Carmine Coluccini. "Synthesis and Coordination Properties of a Water-Soluble Material by Cross-Linking Low Molecular Weight Polyethyleneimine with Armed Cyclotriveratrilene." Polymers 13, no. 23 (2021): 4133. http://dx.doi.org/10.3390/polym13234133.
Full textAbstract:
In this study, a full organic and water-soluble material was synthesized by coupling low molecular weight polyethylenimine (PEI-800) with cyclotriveratrilene (CTV). The water-soluble cross-linked polymer contains hydrophobic holes with a high coordination capability towards different organic drug molecules. The coordinating capability towards hydrophilic drugs (doxorubicin, gatifloxacin and sinomenine) and hydrophobic drugs (camptothecin and celastrol) was analyzed in an aqueous medium by using NMR, UV-Vis and emission spectroscopies. The coordination of drug molecules with the armed CTV unit through hydrophobic interactions was observed. In particular, celastrol exhibited more ionic interactions with the PEI moiety of the hosting system. In the case of doxorubicin, the host–guest detachment was induced by the addition of ammonium chloride, suggesting that the intracellular environment can facilitate the release of the drug molecules.
Dissertations / Theses on the topic "Medium-weight molecules"
1
Фролов, М. О., О. О. Пасічник та О. О. Лобода. "Оцінка вмісту молекул середньої маси в ранньому періоді ізольованої скелетної травми, ускладненої крововтратою". Thesis, Сумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/45028.
Full textAbstract:
Найбільш поширеними маркерами ендотоксинів є молекули середньої маси (МСМ), накопиченням яких супроводжується дисфункція детоксикуючих систем організму.
Метою нашої роботи є оцінка особливостей накопичення МСМ в гострий період і період ранніх проявів травматичної хвороби на тлі ізольованої скелетної травми в залежності від інтенсивності крововтрати.
2
Bella, Redha Fenouillot-Rimlinger Françoise Falk Laurent. "Diffusion and reaction of low molecular weight reactants in molten polymer medium characterization and modelling /." Villeurbanne : Doc'INSA, 2007. http://docinsa.insa-lyon.fr/these/pont.php?id=bella.
Full textAbstract:
Thèse doctorat : Matériaux Polymères et Composites : Villeurbanne, INSA : 2007.<br>Thèse rédigée entièrement en anglais. Résumé étendu en français. Titre provenant de l'écran-titre. Bibliogr. p. 147-159.
3
Bella, Redha. "Diffusion and reaction of low molecular weight reactants in molten polymer medium : characterization and modelling." Lyon, INSA, 2007. http://theses.insa-lyon.fr/publication/2007ISAL0025/these.pdf.
Full textAbstract:
The access to innovative products with original applications is linked to a well understanding of the fundamental phenomena that can occur during polymer reactive processing. The aim of this work is to open a way in this comprehension by developing new tools (rheology) and methods (modelling) to understand the coupling of diffusion and reaction using a simple model system within simple laminar flow geometry for small reacting molecules in viscous media. Based on earlier studies, the choice of a simplified approach was imposed to identify the interactions between mixing, diffusion and reaction using model viscous systems. First of all, a thermoplastic / thermoset blend was caried out to identify the interactions between diffusion and reaction. An asymmetricity has been observed on the gradient of morphology due to the diffusional control of the reaction. This gradient may be explained by three factors: differences in diffusion coefficients, in thermodynamic interactions and in viscosity. These interpretations are multiple and difficult to discriminate. As a solution, these phenomena were uncoupled and the diffusion was primarily studied. Using rheological method and inverse calculations, the diffusion coefficients were calculated for monoamine and monoepoxy in molten polymer. Due to the difference in miscibility of the two reactive species, the diffusion rate of the monoamine, that is fully miscible with the polymer, was not dependent on the molecular weight of the polymer. On the other hand, the monoepoxy is only partially miscible with polymer and was diffusion dependent on molecular weight and on Flory-Huiggins parameters. Finally, the coupling of diffusion and reaction of small reactive species in molten polymer was experimented and modelled. The mixing effect was accounted using simple bilayer geometry. The reaction was diffusion controlled and the time necessary to reach homogeneity in laminar flow was calculated<br>L'accès à des produits innovants avec des applications originales est lié à une bonne compréhension des phénomènes fondamentaux qui peuvent se produire pendant les procédés réactifs des polymères. Le but de ce travail est d'ouvrir un chemin dans cette compréhension en développant de nouveaux outils (rhéologie) et méthodes (modélisation) pour comprendre le couplage de la diffusion et de la réaction dans un système modèle simple en utilisant une géométrie simplifiée d'écoulement laminaire pour de petites molécules réactives dans des milieux visqueux. Basé sur de précédentes études, le choix d'une approche simplifiée a été imposé pour identifier les interactions entre mélange, diffusion moléculaire et réaction en utilisant des systèmes visqueux modèles. Tout d'abord, un mélange thermoplastique/thermodurcissable a été utilisé pour identifier les interactions entre la diffusion et la réaction. On a observé une asymétricité au niveau du gradient de la morphologie qui est provoquée par le control de la réaction par la diffusion. Ce gradient peut être expliqué par trois facteurs : différences des coefficients de diffusion, des interactions thermodynamiques et la viscosité. Ces interprétations sont multiples et difficiles à justifier. Comme solution, ces phénomènes ont été découplés et la diffusion a été étudiée en premier. En utilisant une méthode de calcul par rhéologie inverse, les coefficients de diffusion ont été calculés pour une monoamine et une monoepoxide dans un polymère fondu. En raison de la différence de miscibilité des deux espèces réactives, la vitesse de diffusion de la monoamine, qui est entièrement miscible dans le polymère, ne dépendait pas des masses molaires du polymère. D'autre part, la monoepoxide qui est partiellement miscible dans le polymère, sa diffusion dépendait fortement des masses molaires et des paramètres d’interaction de Flory-Huiggins. Finalement, le couplage de la diffusion et la réaction de petites espèces réactives en milieu fondu visqueux ont été expérimenté et modélisé. L'effet du mélange a été pris en compte en utilisant une géométrie simple en bicouches. La réaction était contrôlée par la diffusion et le temps nécessaire pour atteindre un état homogène dans un flux laminaire a été calculé
4
Kleinhenz, Joseph Patrick. "Medium and higher molecular weight volatile thiols in aged cheddar cheese and their relation to flavor." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1054657696.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2003.<br>Title from first page of PDF file. Document formatted into pages; contains xix, 181 p.; also includes graphics (some col.). Includes bibliographical references (p. 158-168). Available online via OhioLINK's ETD Center
Books on the topic "Medium-weight molecules"
1
Shigeo, Ohkubo, ed. Alpha-clustering and molecular structure of medium-weight and heavy nuclei. Progress of Theoretical Physics, 1998.
Find full text
2
Simulated dynamic response of a multi-stage compressor with variable molecular weight flow medium. National Aeronautics and Space Administration, Langley Research Center, 1995.
Find full text
3
Center, Langley Research, ed. Simulated dynamic response of a multi-stage compressor with variable molecular weight flow medium. National Aeronautics and Space Administration, Langley Research Center, 1995.
Find full textBook chapters on the topic "Medium-weight molecules"
1
Fawcett, W. Ronald. "The Thermodynamics of Liquid Solutions." In Liquids, Solutions, and Interfaces. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195094329.003.0005.
Full textAbstract:
Chemistry in the laboratory very often involves the use of liquid solutions. This is especially true in chemical analysis, where the amount of analyte is easily manipulated when it is dissolved in a solution. Solutions are often the medium for chemical reactions which form the basis of titrations. Other simple analytical procedures are based on absorption spectroscopy, which is used to determine the concentrations of an analyte in solution. Most liquid solutions, also called liquid mixtures, are non-ideal. This follows from the fact that the components are in intimate contact with one another, and that the forces between the various species are usually not the same. As a result, the physical properties of the solution, for example, the vapor pressure of a given component, are usually not simply related to its concentration. This non-ideality leads to the concept of the activity of a solution component. As far as the analytical chemist is concerned, only concentration is ultimately of interest. Thus, if an analysis is based on the measurement of a physical property which in turn depends on the activity of a component, it is very important that the relationship between activity and concentration be understood for the system in question. Activity and its relationship to concentration is defined within the context of chemical thermodynamics. Using the laws which govern phase equilibria and the laboratory observations relating to these processes one can develop a detailed understanding of this relationship. In this chapter the macroscopic concepts of chemical thermodynamics which are relevant to solutions are reviewed. In addition, some simple models based on molecular concepts are discussed. The examples chosen are mainly limited to non-electrolyte solutions, especially those involving polar molecules. Concentration of one component in a two-component system can be expressed in several ways: as a weight/weight ratio, as a volume/volume ratio, or as a weight/volume ratio. Physical chemists clearly prefer to express concentration as a weight/weight ratio because then one has the possibility of estimating the number of moles of both components in the solution. In this case, solution composition is independent of temperature and pressure. On the other hand, the analytical chemist prefers to use a weight/volume ratio.
2
Shaikh, Nissar, Narges Quyyum, Arshad Chanda, et al. "Pulmonary Embolism in COVID-19 Patients: Facts and Figures." In Pulmonary Embolism [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99942.
Full textAbstract:
COVID-19 infection affects many systems in the body including the coagulation mechanisms. Imbalance between pro-coagulant and anticoagulant activities causes a roughly nine times higher risk for pulmonary embolism (PE) in COVID-19 patients. The reported incidence of PE in COVID-19 patients ranges from 3 to 26%. There is an increased risk of PE in hospitalized patients with lower mobility and patients requiring intensive care therapy. Obesity, atrial fibrillation, raised pro-inflammatory markers, and convalescent plasma therapy increases the risk of PE in COVID-19 patients. Endothelial injury in COVID-19 patients causes loss of vasodilatory, anti-adhesion and fibrinolytic properties. Viral penetration and load leads to the release of cytokines and von Willebrand factor, which induces thrombosis in small and medium vessels. D-dimers elevation gives strong suspicion of PE in COVID-19 patients, and normal D-dimer levels effectively rule it out. Point of care echocardiogram may show right heart dilatation, thrombus in heart or pulmonary arteries. DVT increases the risk of developing PE. The gold standard test for the diagnosis of PE is CTPA (computerized tomographic pulmonary angiography) which also gives alternative diagnosis in the absence of PE. Therapeutic anticoagulation is the corner stone in the management of PE and commonly used anticoagulants are LMWH (low molecular weight heparin) and UFH (unfractionated heparin). Mortality in COVID-19 patients with PE is up to 43% compared to COVID patients without PE being around 3%.
3
Odunayo Adejuwon, Adekunle, Marina Donova, Victoria Anatolyivna Tsygankova, and Olubunmi Obayemi. "Characterisation of Endo-Polygalacturonases Activities of Rice (Oryza sativa) Fungal Pathogens in Nigeria, West Africa." In Grain and Seed Proteins Functionality. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94763.
Full textAbstract:
Rice (Oryza sativa) is cultivated in swampy geographical locations of tropical Nigeria, West Africa. Here it is infected by a host of fungal pathogens on the field or contaminated at postharvest. This has led to its loss and reduction in its production in both the national and global market. Lasiodiplodia theobromae and Rhizoctonia solani have recently been identified as the major fungal phytopathogens causing the deterioration of this grain on the field and at postharvest and affecting its production in Nigeria leading to gross capital loss. Hence the need to determine physiological control measures for the eradication of both phytopathogens on the field and at postharvest. In this study, tropical strains of Lasiodiplodia theobromae and Rhizoctonia solani obtained from deteriorated rice (Oryza sativa) were grown in a growth nutrient medium composed of MgSo4.7H20, K2HPO4, FeSO4.7H20, potassium nitrate and pectin at 30°C. Endo-Polygalacturonase activities were produced by the fungal isolates in the growth medium within ten days. The endo-polygalacturonases from both fungi were purified by a combination of ammonium sulphate precipitation, dialysis, gel filtration (on Sephadex G-100 column) and ion-exchange chromatography (on CM-Sephadex C-50 and CM-Sephadex C-25 columns). The molecular weight of endo-polygalacturonase from the Lasiodiplodia theobromae using Sephadex G-100 was estimated as 124,000 Daltons while that of the Rhizoctonia solani was estimated as 92,000 Daltons. The purified endo-polygalcuronase from the Lasiodiplodia theobromae exhibited optimum activity at 30°C and at pH 4.5 while that from the Rhizoctonia solani exhibited optimum activity at 32°C and at pH 5.0. The purified endo-polygalacturonases from both fungi exhibited optimum activities at 0.2% pectin concentration. They were stimulated by Ca2+ but inhibited by ethlylenediamine tetracetic acid (EDTA) and 2,4-dinitrophenol. The purified endo-polygalacturonase from the Lasiodiplodia theobromae lost 80% of its activity within 20 minutes of heat at 80°C. While the purified endo-polygalacturonase from the Rhizoctonia solani lost 82% of its activity within 20 minutes of heat at 80°C. Potassium nitrate as nitrogen source in the defined growth medium with pectin as carbon source supported highest activity of endo-polygalacturonase by the Lasiodiplodia theobromae while ammonium chloride as nitrogen source in the defined growth medium with pectin as carbon source supported highest activity of endo-polygalacturonase by the Rhizoctonia solani. In conclusion, the conditions inhibiting endo-polygalacturonases from Lasiodiplodia theobromae and Rhizoctonia solani capable of degrading the pectin portion of rice (Oryza sativa) can be adapted as feasible control measures limiting the infection and contamination of rice (Oryza sativa) by these phytopathogens on the field and at postharvest. Temperature and pH extreme from 30°C and pH 4.5 will be feasible inhibitory control measures for the growth of Lasiodiplodia theobromae on rice (Oryza sativa) in Nigeria while temperature and pH extreme from 32°C and pH 5.0 will inhibit growth of Rhizoctonia solani on the grain. These physiological conditions will preserve pectin in rice (Oryza sativa) from degradation by these two fungal phytopathogens.
Conference papers on the topic "Medium-weight molecules"
1
Gawas, Kiran, Chandrashekhar Khandekar, Katrina Akita, Janet Ngo, and John Hazlewood. "Optimize Performance Through Customization of Paraffin Inhibitor Molecular Structure." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204298-ms.
Full textAbstract:
Abstract Deposition of high molecular weight paraffins and subsequent plugging is one of the most prevalent flow assurance risks in both onshore and offshore oil and gas production. Several thermal (e.g., insulation, heat treatment), mechanical (e.g., pigging, cutting), and chemical (e.g., paraffin crystal modifiers, dispersants, and solvents) techniques are used for wax deposition prevention and remediation. Various chemistries such as long-chain poly alkyl acrylates, olefin vinyl acetate copolymers, alkyl phenol resins and esterified olefin maleic anhydride polymers are used as wax crystal modifiers. This study investigates the impact of the alpha olefin maleic anhydride co-polymers structure on the composition and deposition of paraffin. Eight different crude samples from condensates to black oils with API gravity in the range of 30 to 50° were studied. The focus of this research is on paraffin inhibitors’ effectiveness in reducing paraffin deposition that is driven by thermal driving force between the bulk oil and the pipe wall. Inhibitor performance was measured by cold finger testing. Three different alpha olefin (short, medium and long) maleic anhydrides esterified with different fatty alcohols with varying chain lengths were tested for performance. The impact of selected chemicals on amount and composition of paraffin deposit under different test conditions was studied. Wax deposit composition was characterized using high temperature gas chromatography (HTGC) and differential scanning calorimetry (DSC) techniques. Effect of pendant side chain length as well as the composition and molecular weight of the alpha-olefin backbone on paraffin inhibition is presented. Additionally, the impact of test conditions on the composition and hence the performance of the selected chemicals is investigated. We present our findings on selective inhibition of lower molecular weight paraffin depending on the composition of the oil, leaving a much harder deposit rich in high molecular weight paraffin. This is an important observation since a hard deposit would be extremely difficult to remediate in the field and should be avoided. In summary this work provides guidelines for tailoring paraffin inhibitor molecules based on crude oil composition and field conditions, through a systematic structure-performance study.
2
Dusseault, Maurice B., Shikui Li, Hongxue Han, Jingyan Li, and Haibo Wu. "Flooding Thin Low-Permeability Layers With a New Salt-Resistant, Medium-Molecular-Weight Polymer." In SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 2007. http://dx.doi.org/10.2118/109627-ms.
Full text
3
Ju, Donghong, and Mary A. Kosir. "Abstract 946: Characterize and identify secreted high molecular weight heparanase from PC3M conditioned medium." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-946.
Full text
4
Vannucchi, S., F. Pasquali, P. Bianchi-ni, and M. Ruggiero. "BINDING AND METABOLISM OF HEPARIN BY ENDOTHELIAL CELLS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644187.
Full textAbstract:
In this study we show that bovineadrenal capillary endothelial cells(BACE) contain heparin (HP); this HP has been found associated with the cell surface (i.e; trypsin-removable^and intracellularly. How-ever, experiments with [ sjsodium sulfate labelling, demonstrate that BACE cells donot synthesize HP de novo, but they uptake it from serum. We have studied binding, uptake, and metabolism odifferent molecular weight-HPs: 13 Kd-HP from bovine source, 14 Kd-HP from porcine source, 4.5 Kd, and 2.5-HP fragments. Comparison among different HPs, was carried out by calculating the IC from competition curves for [3HJ- HP. Binding of labelled-HP to BACE cells was specificand saturable. Dextran sulfate and glycosaminoglycans did not compete for binding; only heparan sulfate showed some competition. Binding of different HPs was strictly dependent on their molecular weight; 2.5 Kd- HP was unable to bind to cells, although sulfation degree of this fragment and of unfractionated HP was almost identical. Therefore, we assume that a specific oligosaccharide sequence could be responsible for HP binding to BACE cells; this hypothetical "binding sequence" could then be lost in very low molecular weight-HP fragments. BACE cells are also able to internalize HP, and they release its low molecular weight degradation products into culture medium. Thus we suggest that endothelial cells might represent a site for the metabolism of endogenous and exogenous HP in vivo.
5
Mortazavi, Farzam, and Debjyoti Banerjee. "Review of Molten Salt Nanofluids." In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7316.
Full textAbstract:
Literature review of molten salt nanofluids is performed in this study with focus on the thermo-fluidic properties and performance in thermal management applications. The colloidal mixture of nanoparticles in a base liquid phase is called nanofluid. Molten salts such as alkali nitrate eutectics, alkali carbonate eutectics and alkali chloride eutectics have high melting temperatures. These materials are suitable for various high temperature applications, including as Heat Transfer Fluid (HTF), Thermal Energy Storage (TES), Concentrated Solar Power (CSP) plants, nuclear power, etc. The major drawback of molten salt materials is their low thermal conductivity and specific heat capacity. Enhancing the thermo-physical properties of molten salt materials can lower the cost of power production involving these materials (e.g., as HTF and/ or TES in CSP or nuclear power plants. Mixing molten alt eutectics with nanoparticles (e.g., molten salt nanofluids) can provide a cost-effective technique for enhancing the specific heat capacity and thermal conductivity which in turn can enable the reduction in the cost of power production. In this review - the following topics involving molten salt nanofluids were explored: thermo-physical property measurements, numerical modeling (e.g., Molecular Dynamics/ MD simulations), materials characterization (e.g., using electron microscopy techniques — such as SEM and TEM). For example, SEM studies in conjunction with MD simulation results confirm the formation of a dense layer of fluid molecules on the surface of nanoparticles that can enhance the specific heat capacity of these molten salt nanomaterials. Subsequently the concepts of nanofins was explored (which involves the study of interfacial thermal impedance, such as resistance, capacitance and diodicity). The contribution of these interfacial thermal impedances to the enhancement of specific heat capacity and thermal conductivity are also explored. Specific heat enhancement as high as 100% has been observed for various molten salt eutectics when doped with 1.5% (weight) silica nanoparticles. Various synthesis protocols such as one-step, two-step and three-step methods as well as conventional experimental methods used for specific heat capacity measurement are compared and examined. A review of the effects of concentration, nanoparticle size, temperature, base fluid, and nanofluid chemical properties is also performed. Other topics of interest are the anomalous enhancement of thermal conductivity in molten salt nanofluids which contradict typical predictions obtained from using the effective medium theory. The available data in literature shows enhancement in thermal conductivity by as much as 35–45% for carbonate eutectics doped with silica nanoparticles at 1% mass fraction. The possible mechanisms suggested for this improvement are briefly discussed and compared with experimental observations (e.g., using SEM). In addition, nanofluids often display non-Newtonian rheological behavior. This necessitates a rigorous study, since the applications of nanofluids will impact the required pumping power. Studies show that the rheological properties of molten salt nanofluids are a function of base salt composition, shape of nanoparticles selected, chemical formula of nanoparticles, concentration of nanoparticles, size of nanoparticles, temperature, shear rate and synthesis protocol of the nanofluid. Several models are introduced to predict the viscosity variation along with their advantageous and disadvantages. SEM results show agglomeration of nanoparticles can be reduced by doping the nanofluids with very small values of mass fractions of additives such as Gum Arabic.
6
Libby, Peter, Stephen J. C. Warner, and Louis K. Birinyi. "THE VESSEL WALL AS A SOURCE OF VASORHGOLATORY AND IMMDNOSTIMOLATORY CYTOKINES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643982.
Full textAbstract:
The cytokines Interleukin-1 (IL-1) and Tumor Necrosis Factor (TNF, also known as cachectin) exhibit multiple effects on circulating blood cells and cells of the blood vessel wall. For example, these mediators elicit a coordinated Drogram of functions of endothelial cells (EC) that promotes blood coagulation and thrombosis, and lead to clot stabilization. Furthermore, IL-1 and TNF promote adherence to vascular endothelium of leukocytes of many classes.Thus, these cytokines are likely to be involved in signaling the pathologic changes in blood vessels that characterize a number of inflammatory or infectious processes. These two cytokines were originally isolated frcm activated human mononuclear phagocytes, hence their comnon designation as monokines and the terminology "interleukin". However, recent findings have broadened this concept considerably. It is now clear that many cell types can produce IL-1-1ike activity.Several groups showed that human vascular EC can secrete material that stimulates proliferation of thymocytes incubated with suboptima1 doses of the mitogenic lectin phytohemagglutinin, a typical acitivty of IL-1 (thymocyte costimulation).Two related but distinct genes cloned frcm human peripheral blood monocytes encode IL-1 molecules. In human blood monocytes stimulated with bacterial lioopolysaccharide (LPS) IL-1 beta (pi ∼ 7) is the major form expressed while IL-1 alpha (pi ∼ 5) is the less abundant species secreted by human monocytes under these conditions. We found that EC and smooth muscle cells (SMC) isolated from adult human vessels can express these same IL-1 genes. LPS, a standard stimulus to IL-1 secretion in the monocyte, caused accumulation of IL-1 beta mRNA in both vascular cell types. Endothelial cells frcm adult human vessels also contained IL-1 alpha mRNA when treated with LPS in the presence of cycloheximide and LPS-stimulated smooth muscle cells contained RNA that hybridized with an IL-1 alpha cDNA probe as well. Although both vascular cell types can transcribe these IL-1 genes, the time course of this response differs. LPS induced IL-1 beta mRNA production by SMC maximally at 4-6 hr., whereas maximal IL-1 induction by LPS in EC occured 1 day after initiation of the exposure. Actinanycin D (1 ug/ml) blocked 3H-uridine incorporation into macromolecules by > 95% in both EC & SMC, and prevented the LPS-induced increases in IL-1 mRNA levels in these cells. This result suggests that this potentially injurious stimulus causes IL-1 mRNA accumulation by an increase in rates of transcription. These LPS-induced increases in IL-1 mRNA levels corresponded to production of biologically active IL-1 determined as thymocyte costimulation activity. Interestingly, gel filtration experiments revealed a molecular weight of around 22kD for both SMC and EC-derived IL-1 secreted into culture medium in response to LPS. This molecular weight contrasts with the 17 kD species which is the fully processed product secreted frcm activated human monocytes. A possible explanation for this disparity is that the vascular cells secrete a partially processed intermediate form of mature IL-1. Other stimuli for IL-1 mRNA accumulation and secretion of biological activity include TNF and IL-1 itself. Recombinant human INF (≥ 10 ng/ml) increased IL-1 beta mRNA levels in EC & SMC, and caused the EC & SMC to release IL-1-1 ike thymocyte costimulation activity. Of interest is the recent observation that IL-1 itself can stimulate expression of IL-rl genes in vascular wall cells. Both IL-1 aloha and beta can increase IL-1 beta mRNA content in EC & SMC. Hris observation was confirmed with homogenous IL-1 prepared by recombinant DNA technologies (rIL-1). These findings raise the possibility of a novel positive feedback loop in vascular pathophysiology. We also found that rIL-1 alpha or beta also induced the production of prostaglandin E2 (PGE2) by both vascular SMC & EC. This prostanoid, induced by IL-1, inhibits thymocyte _ proliferation. Thus, IL-1 not only induced its own expression but increased production of this immunosuppressive prostanoid. This mechanism provides a potential negative control loop in regulation of the local immune response in blood vessels. Vie conclude that these cells of the blood vessel wall are a source of the potent vasoregulatory and immune mediators IL-1 alpha and beta. Since IL-1 influences the thrombotic, hemostatic, and fibrinolytic functions of endothelium, as well as other responses to acute injury, our findings suggest novel local control mechanisms that may be important in a variety of pathologic states.
7
Camacho, M., A. Fabra, F. Carretero, M. Borrell, I. Millet, and M. L. Rutllant. "A MONOCLONAL BASED ELISA FOR HUMAN u-PA QUANTIFICATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644844.
Full textAbstract:
An ELISA has been developped for quantifiing the anti gen levels of u-PA present in human plasma, tissue and cell extracts, conditioned medium and others biological fluids.The assay was set up using PVC plates coated with rabbit anti u-PA IgG and a monoclonal antibody against human u-PA as second antibody (UKM23 obtained in our laboratory as previously described).Detection was performed with a rabbit anti-mouse IgG conjugated with horseradish peroxidase.By immunoblotting technique the monoclonal antibody used UKM23 , recognizes all human molecular weight spe cies and an additional band of 81 KD in human plasma. Also recognizes the u-PA present in conditioned medium from HT-1080 cell line.The detection limit of ELISA assay is 0,1 ng of total u-PA.The first assay in human plasma from healty volun ters, shows u-PA levels of 4,39 ± 0,94 ng/ml.This study was supported by grants from the CAICYTn9 1258/81 and 3628/86.
8
Askerov, Fakhreddin, Solmaz Kadimova, Samira Ibragimova, and Armilla Azimova. "PECULIARITIES OF THE SPECTRA OF AROMATIC AMINO ACIDS OF MEDIUM MOLECULAR WEIGHT PEPTIDES IN VARIOUS TISSUES WITH LOW-PROTEIN NUTRITION OF THE BODY." In XVII INTERNATIONAL INTERDISCIPLINARY CONGRESS NEUROSCIENCE FOR MEDICINE AND PSYCHOLOGY. LCC MAKS Press, 2021. http://dx.doi.org/10.29003/m2040.sudak.ns2021-17/65-66.
Full text
9
Albano, Giusy D., Anna Bonanno, Luca Cavalieri, et al. "Effect of high, medium, and low molecular weight hyaluronan on inflammation and oxidative stress in an in vitro model of human nasal epithelial cells." In ERS International Congress 2016 abstracts. European Respiratory Society, 2016. http://dx.doi.org/10.1183/13993003.congress-2016.pa5064.
Full text
10
Piovella, F., R. Lombardi, M. Vigotti, A. B. Federici, P. M. Mannucci, and E. Ascari. "VON WILLEBRAND FACTOR MULTIMERS IN CULTURED HUMAN ENDOTHELIAL CELLS: COMPARISON BETWEEN CELLULAR STORAGE POOL AND SUPERNATANT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644100.
Full textAbstract:
The multimeric composition of von Willebrand factor (vWf) from cultured human endothelial cells (h.e.c.) has been compared with the multimeric composition of vWf from h.e.c. culture supernatant, human normal platelets and plasma. H.e.c. were derived from umbilical cord veins by collagenase digestion, seeded in culture flasks and grown to confluence in TC 199 culture medium, supplemented with 20% foetal calf serum (FCS). At confluency, cells were harvested by rubber policeman, resuspended in 500 |o.l HBSS with protease inhibitors and stored with culture media until assay. H.e.c. and platelet lysates were obtained by freezing-and-thawing (5 times) and by the addition of 1% Sodium Dodecyl Sulphate (SDS) before centrifugation at 10,000 x g for 20 min at 20°C. Plasma, culture supernatants and cell lysates supernatants were run under the same conditions in an SDS 1.4%, LGT-agarose electrophoresis system using a discontinous buffer. Multimeric patterns were shown by radiolabelled affinity purified rabbit anti-human polyclonal antibody. In all the experiments cultured h.e.c. supernatants exhibited all the set of multimers of vWf usually observed in normal plasma. When vWf from cultured h.e.c. extracts was analyzed, a set of multimers with higher molecular weight was shown, with a pattern very similar to platelet's. We conclude that vWf stored in h.e.c. compartments is characterized by higher molecular weight multimers than culture supernatants. This behaviour recalls the differences recorded between plasma and platelet vWf.