Relevant bibliographies by topics / Urea – Spectra

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Academic literature on the topic 'Urea – Spectra'

Author: Grafiati

Published: 4 June 2021

Last updated: 16 February 2022

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Journal articles on the topic "Urea – Spectra"

Bakibaev, А. А., М. Zh Sadvakassova, V. S. Malkov, R. Sh Еrkasov, A. A. Sorvanov, and O. A. Kotelnikov. "Study of the biologically active acyclic ureas by nuclear magnetic resonance." Bulletin of the Karaganda University. "Chemistry" series 100, no. 4 (2020): 60–74. http://dx.doi.org/10.31489/2020ch4/60-74.

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A wide variety of acyclic ureas comprising alkyl, arylalkyl, acyl, and aryl functional groups are investigated by nuclear magnetic resonance spectroscopy. In general, spectral characteristics of more than 130 substances based on acyclic ureas dissolved in deuterated dimethyl sulfoxide at room temperature are studied. The re-sults obtained based on the studies of 1H and 13C NMR spectra of urea and its N-alkyl-, N-arylalkyl-, N-aryl- and 1,3-diaryl derivatives are presented, and the effect of these functional groups on the chemical shifts in carbonyl and amide moieties in acyclic urea derivative

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Eddy, Christopher V., and Mark A. Arnold. "Near-Infrared Spectroscopy for Measuring Urea in Hemodialysis Fluids." Clinical Chemistry 47, no. 7 (2001): 1279–86. http://dx.doi.org/10.1093/clinchem/47.7.1279.

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Abstract Background: Near-infrared spectroscopy is proposed as a method for providing real-time urea concentrations during hemodialysis treatments. The feasibility of such noninvasive urea measurements is evaluated in undiluted dialysate fluid. Methods: Near-infrared spectra were collected from calibration solutions of urea prepared in dialysate fluid. Spectra were collected over three distinct spectral regions, and partial least-squares calibration models were optimized and compared for each. Selectivity for urea was demonstrated with two-component samples composed of urea and glucose in the

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Olesberg, Jonathon T., Mark A. Arnold, and Michael J. Flanigan. "Online Measurement of Urea Concentration in Spent Dialysate during Hemodialysis." Clinical Chemistry 50, no. 1 (2004): 175–81. http://dx.doi.org/10.1373/clinchem.2003.025569.

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Abstract Background: We describe online optical measurements of urea in the effluent dialysate line during regular hemodialysis treatment of several patients. Monitoring urea removal can provide valuable information about dialysis efficiency. Methods: Spectral measurements were performed with a Fourier-transform infrared spectrometer equipped with a flow-through cell. Spectra were recorded across the 5000–4000 cm−1 (2.0–2.5 μm) wavelength range at 1-min intervals. Savitzky–Golay filtering was used to remove baseline variations attributable to the temperature dependence of the water absorption

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Campbell, Blair F., and Leigh B. Clark. "Polarized vacuum ultraviolet spectra of crystalline urea." Journal of the American Chemical Society 111, no. 21 (1989): 8131–36. http://dx.doi.org/10.1021/ja00203a011.

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Bakibaev, A. A., S. Yu Panshina, O. V. Ponomarenko, V. S. Malkov, O. A. Kotelnikov, and A. K. Tashenov. "1D and 2D NMR spectroscopy for identification of carbamide-containing biologically active compounds." Bulletin of the Karaganda University. "Chemistry" series 101, no. 1 (2021): 71–81. http://dx.doi.org/10.31489/2021ch1/71-81.

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Urea (carbamide) is the main end product of amino acids' metabolism in mammals. Extensive research in the field of urea chemistryhas contributed to the creation of many biologically active and other compounds based on the carbamide fragment NH–CO–NH. The substituting groups of urea directly affect its properties and characteristics which are reflected in the NMR spectral data and this circumstance can be the basis for the identification of urea derivatives. In this work, chemical shifts in the NMR spectra of urea and its acyclic structure, barbituric series, imidazolidinone series and bicyclic

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Petibois, Cyril, Georges Cazorla, André Cassaigne, and Gérard Déléris. "Plasma Protein Contents Determined by Fourier-Transform Infrared Spectrometry." Clinical Chemistry 47, no. 4 (2001): 730–38. http://dx.doi.org/10.1093/clinchem/47.4.730.

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Abstract Background: Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins. Methods: We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption

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Jirman, Josef, and Pavel Pech. "17O NMR Spectra of Acylated Ureas and Thioureas." Collection of Czechoslovak Chemical Communications 57, no. 6 (1992): 1278–81. http://dx.doi.org/10.1135/cccc19921278.

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17O NMR spectra of ten acyl- and diacylureas (I-V) and thioureas (VII-X) were measured. 17O NMR chemical shifts of the ureido oxygen in the ureas range from 240 to 310 ppm, those of the acyl oxygens from 377 to 400 ppm (acetyl groups) and 359 to 389 ppm (benzoyl groups), the half-widths being tens to hundreds Hz. Acylation of urea to the diacyl stage has an almost twice as large effect on the chemical shift of the ureido oxygen than has the monoacylation. From the viewpoint of 17O NMR shifts, no significant differences has been found in the influence of ureido and thioureido groups on the tran

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Nyanzi, Steven A., Maureen Isiko, Francis Kateregga, and Wolfgang Schwack. "Second-Derivative Spectrometric Determination of Urea in Milk Using the Diacetyl Monoxime Reagent." Journal of AOAC INTERNATIONAL 93, no. 2 (2010): 485–91. http://dx.doi.org/10.1093/jaoac/93.2.485.

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Abstract The application of derivative spectrometry to resolve overlapping spectra and improve the sensitivity and selectivity of the colorimetric determination of urea in milk using diacetyl monoxime is presented. With first-derivative (1D) spectrometry, the max of the colored complex was established to be 525 nm. The absorption band at max 525 nm in normal absorption (0D) spectrometry was resolved into three clearly distinct spectral bands with minima at 497, 530, and 566 nm with second-derivative (2D) spectrometry. With the second-derivative (2D530) technique, the depth of the trough of the

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Ilczyszyn, M. M., H. Ratajczak, and A. J. Barnes. "Polarized infrared and Raman spectra of urea-phosphoric acid and urea-arsenic acid single crystals." Journal of Raman Spectroscopy 23, no. 1 (1992): 1–13. http://dx.doi.org/10.1002/jrs.1250230102.

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Zeng, Fan Ming, Chun Li, Hai Lin, Xiao Dong Yang, Dan Wang, and Jing He Liu. "Preparation of Nd:YAG Nanopowders by the Urea Co-Precipitation." Applied Mechanics and Materials 511-512 (February 2014): 78–80. http://dx.doi.org/10.4028/www.scientific.net/amm.511-512.78.

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Nd:YAG nanopowder was prepared by urea co-precipitation method. XRD, TG-DTA, SEM and spectra analysis were utilized to study the properties of the powder. Results indicated that fine Nd:YAG nanopowder can be acquired at 1000°C for 10h. The fluorescence spectra shown that the strongest peak was located at 1061nm, corresponding to the 4F3/24I11/2 energy level transition of Nd3+ ion.

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Dissertations / Theses on the topic "Urea – Spectra"

Sun, Yatian. "Comparison and combination of near-infrared and Raman spectra for PLS and NAS quantitation of glucose, urea and lactate." Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/5064.

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Noninvasive glucose sensing has been studied widely. Near infrared (NIR) absorption spectroscopy and Raman scattering spectroscopy are proposed individually and combined as methods for glucose measurement in a three component sample matrix. In both techniques, the light transmits through human skin and a spectrum is collected. The research described in this thesis is like this. The use of individual NIR spectra data and individual Raman spectra data can give a good prediction ability of the partial least-squares (PLS) calibration model. Since the NIR and Raman spectroscopies have complementary

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Books on the topic "Urea – Spectra"

Nakamoto, Kazuo. Drug-DNA interactions: Structure and spectra. John Wiley & Sons, 2008.

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Drug-DNA Interactions: Structures and Spectra (Methods of Biochemical Analysis). Wiley, 2008.

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Stuewer, Roger H. New Particles. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198827870.003.0007.

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In December 1931, Harold Urey discovered deuterium (and its nucleus, the deuteron) by spectroscopically detecting the faint companion lines in the Balmer spectrum of atomic hydrogen that were produced by the heavy hydrogen isotope. In February 1932, James Chadwick, stimulated by the claim of the wife-and-husband team of Irène Curie and Frédéric Joliot that polonium alpha particles cause the emission of energetic gamma rays from beryllium, proved experimentally that not gamma rays but neutrons are emitted, thereby discovering the particle whose existence had been predicted a dozen years earlier

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Lameire, Norbert, Raymond Vanholder, and Wim Van Biesen. Clinical approach to the patient with acute kidney injury. Edited by Norbert Lameire. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0222_update_001.

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The prognosis of acute kidney injury (AKI) depends on early diagnosis and therapy. A multitude of causes are classified according to their origin as prerenal, intrinsic (intrarenal), and post-renal.Prerenal AKI means a loss of renal function despite intact nephrons, for example, because of volume depletion and/or hypotension.There is a broad spectrum of intrinsic causes of AKI including acute tubular necrosis (ATN), interstitial nephritis, glomerulonephritis, and vasculitis. Evaluation includes careful review of the patient’s history, physical examination, urinalysis, selected urine chemistrie

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Book chapters on the topic "Urea – Spectra"

Manjunatha, Krishtappa, Veerabhadrappa Jagadeesha Angadi, Brian Jeevan Fernandes, and Keralapura Parthasarathy Ramesh. "Synthesis and Study of Structural and Dielectric Properties of Dy-Ho Doped Mn-Zn Ferrite Nanoparticles." In Ferrite [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99264.

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The Dy-Ho doped Mn-Zn Ferrite nanoparticles have been synthesized by solution combustion method using mixture of fuels as glucose and urea. The synthesized samples of structural properties were characterized through XRD (X-ray diffraction) and dielectric properties were studied through impedance analyzer. The XRD patterns of all samples confirms the spinel cubic structure having space group Fd3m. Further all synthesized samples reveal the single-phase formation without any secondary phase. The lattice parameters and hopping lengths were increases with increase of Dy-Ho concentration. SEM micrographs shows the porous nature for all samples. The crystallite size increases with increase of Dy-Ho concentration. The Dielectric properties of all the samples were explained by using Koop’s phenomenological theory. The real part of dielectric constant, imaginary part of dielectric constant and dielectric loss tangent were decreases with increase of frequency. Th AC conductivity increases with increase of frequency. The real part of impedance spectra decreases with increase of frequency for all samples. The Cole-Cole plots shows the one semicircle for all samples. The high ac conductivity and low dielectric loss observed for all samples at high frequency region and this samples are reasonable for power transformer applications at high frequencies.

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Minagawa, Masatomo, Jun Yatabe, Fumio Yoshii, Shin Hasegawa, Nobuhiro Sato, and Tomochika Matsuyama. "Solubility, Discoloration, and Solid-State 13C NMR Spectra of Stereoregular Poly(Vinyl Chloride) Prepared by Urea Clathrate Polymerization at Low Temperatures." In Nuclear Magnetic Resonance. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.90784.

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Peng, Xiangdong, and Jerson L. Silva. "High-Pressure NMR Studies of the Dissociation of Arc Represser and the Cold Denaturation of Ribonuclease A." In High Pressure Effects in Molecular Biophysics and Enzymology. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195097221.003.0011.

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We begin this article with a brief discussion of the specialized high-resolution NMR instrumentation developed for high-pressure studies of biochemical systems. We then present the potential for the unique information content of high-pressure NMR spectroscopy as illustrated by the results of two NMR studies performed recently in our laboratory. Different denatured states of Arc represser are characterized by one-dimensional (1D) and two-dimensional (2D) NMR. Increasing pressure promotes sequential changes in the structure of Arc represser: from the native dimer through a predissociated state to a denaturated molten globule monomer. A compact state (molten globule) of Arc represser is obtained in the dissociation of Arc represser by pressure, whereas high temperature and urea induce dissociation and unfolding to less structured conformations. The presence of NOEs (Nuclear Overhauser Enhancement) in the β-sheet region in the dissociated state suggests that the intersubunit β-sheet (residues 6–14) in the native dimer is replaced by an intramonomer β-sheet. Changes in 2D NMR spectra prior to dissociation indicate the existence of a predissociated state that may represent an intermediate stage in the folding and subunit association pathway of Arc represser. The cold denaturation study of ribonuclease A has shown that high pressure can be utilized not only to perturb the protein structure in a controlled way but also to lower the freezing point of aqueous protein solutions substantially. As a result, one can access subzero temperatures and carry out cold denaturation studies of proteins. The results of the NMR study of the reversible cold denaturation are compared with the heat and pressure denaturation of bovine pancreatic ribonuclease A. High-resolution NMR spectra of complex molecules in the liquid phase usually exhibit a great deal of structure and yield a wealth of information about the molecule. Therefore, it is not surprising that multinuclear high-resolution Fourier transform NMR spectroscopy at high pressure represents the most promising technique in studies of the pressure effects on biochemical systems (Jonas & Jonas, 1994). The high information content of the various advanced NMR techniques, including 2D NMR techniques such as NOESY, COSY, and ROESY, have yet to be fully exploited in high-pressure NMR experiments.

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NYQUIST, R. "Carboxamides, Ureas, Thioureas, Imidazolidinones, Caffeine, Isocaffeine, Uracils, Imides, Hydantoins, and s-Triazine(1H, 3H, 5H)-Triones." In Interpreting Infrared, Raman, and Nuclear Magnetic Resonance Spectra. Elsevier, 2001. http://dx.doi.org/10.1016/b978-012523475-7/50176-5.

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Hoffmann, Georg F., and Stefan Kölker. "Protein-dependent inborn errors of metabolism." In Oxford Textbook of Medicine, edited by Timothy M. Cox. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0226.

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Protein-dependent inborn errors of metabolism are caused by inherited enzyme defects of catabolic pathways or intracellular transport of amino acids. Most result in an accumulation of metabolites upstream of the defective enzyme (amino acids and/or ammonia), causing intoxication. Protein-dependent metabolic diseases usually have a low prevalence except for some high-risk communities with high consanguinity rates. However, the cumulative prevalence of these disorders is considerable (i.e. at least >1:2000 newborns) and represents an important challenge for all public health systems. Types and clinical presentation of protein-dependent inborn errors of metabolism—this chapter discusses amino acid disorders, organic acid disorders, and urea cycle defects. The disease spectrum is broad, but follows a distinct pattern in specific disorders. Investigation and management—every infant presenting with symptoms of unexplained metabolic crisis, intoxication, or encephalopathy requires urgent evaluation of metabolic parameters, including analyses of arterial blood gases, serum glucose and lactate, plasma ammonia and amino acids, acylcarnitine profiling in dried blood spots, and organic acid analysis in urine. This chapter discusses the basic principles of acute emergency therapy and of long-term treatment, which aims principally to mitigate the metabolic consequences of enzyme deficiencies by compensating for them. Successful treatment of affected individuals is often difficult to achieve. Careful supervision in metabolic centres involving an experienced multidisciplinary team is invaluable for the best outcome.

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"Buzz Spector: Kafka Face to Face As If Sur-face Text-ure." In Visible Writings. Rutgers University Press, 2019. http://dx.doi.org/10.36019/9780813554556-011.

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Conference papers on the topic "Urea – Spectra"

Thomas, Jessica, Zbigniew Kisiel, and Ivan Medvedev. "ROTATIONAL SPECTRA OF UREA IN ITS GROUND AND FIRST EXCITED VIBRATIONAL STATES." In 69th International Symposium on Molecular Spectroscopy. University of Illinois at Urbana-Champaign, 2014. http://dx.doi.org/10.15278/isms.2014.ta09.

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Mullaney, John, Bernard Golding, Luke Lewis-Borrell, Anthony Legon, Nick Walker, and Chris Medcraft. "THE ROTATIONAL SPECTRUM OF THE UREA···ISOCYANIC ACID COMPLEX." In 71st International Symposium on Molecular Spectroscopy. University of Illinois at Urbana-Champaign, 2016. http://dx.doi.org/10.15278/isms.2016.wc07.

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Shanthi, N. Theresita, P. Selvarajan, A. S. J. Lucia Rose, P. Predeep, Mrinal Thakur, and M. K. Ravi Varma. "Synthesis, Growth, Spectral and Optical Properties of Glycinyl Urea Single Crystal." In OPTICS: PHENOMENA, MATERIALS, DEVICES, AND CHARACTERIZATION: OPTICS 2011: International Conference on Light. AIP, 2011. http://dx.doi.org/10.1063/1.3646812.

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Kisiel, Zbigniew, Ivan Medvedev, and Jessica Thomas. "THE LOWEST VIBRATIONAL STATES OF UREA FROM THE ROTATIONAL SPECTRUM." In 69th International Symposium on Molecular Spectroscopy. University of Illinois at Urbana-Champaign, 2014. http://dx.doi.org/10.15278/isms.2014.ta10.

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De Giorgi, M. G., E. Pescini, S. Campilongo, G. Ciccarella, D. Fontanarosa, and A. Ficarella. "Effects of Emulsified Fuel on the Performance and Emission Characteristics of Aeroengine Combustors." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-92039.

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Abstract The aim of the present work is the experimental investigation of the effects of the addition of water and urea into jet fuels, on the reduction of nitrogen oxides (NOx) emissions and eventually improvement of the lean flame stability in aeroengine combustors. Experiments have been carried out using a 300-kW liquid-fueled swirling combustor. Various urea and/or water concentrations have been tested at the same fuel/air ratio. In order to study the flame behavior, non-invasive optical diagnostic techniques, as charge-coupled device (CCD) cameras in different spectral ranges (Visible and

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LIU, Xiao-Jing, Xin SUN, Jing-Hua GUO, and Miao-Juan REN. "Electronic Absorption Spectral Investigations and Thermodynamic Properties of Urea Maleic Acid for Nonlinear Optical Applications." In 3rd International Conference on Material Engineering and Application (ICMEA 2016). Atlantis Press, 2016. http://dx.doi.org/10.2991/icmea-16.2016.34.

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Blanco, Susana, Anthony Legon, Nick Walker, Chris Medcraft, and John Mullaney. "PURE ROTATIONAL SPECTRUM AND MOLECULAR GEOMETRY OF AN ISOLATED COMPLEX OF IMIDAZOLE AND UREA." In 71st International Symposium on Molecular Spectroscopy. University of Illinois at Urbana-Champaign, 2016. http://dx.doi.org/10.15278/isms.2016.rg12.

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Ten, G. N., O. E. Glukhova, A. M. Semagina, M. M. Slepchenkov, and V. I. Baranov. "The structure definition of complementary pairs Ade-Ura in different phase states using IR spectra." In Saratov Fall Meeting 2014, edited by Elina A. Genina, Vladimir L. Derbov, Kirill V. Larin, Dmitry E. Postnov, and Valery V. Tuchin. SPIE, 2015. http://dx.doi.org/10.1117/12.2180072.

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