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Sample records for aliento con urea-13c

  1. Validación de método simplificado de la prueba en aliento con urea-13C para diagnóstico de infección por Helicobacter pylori Validation of a simplified method of the 13C urea breath test for diagnosis of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    N. X. Ortiz-Olvera Nayeli

    2007-07-01

    Full Text Available Objetivo: validar un método simplificado de la prueba en aliento con urea-13C (PAU-13Cs para el diagnóstico de infección por Helicobacter pylori (H. pylori, con administración simultánea de 50 mg de urea-13C y 2 g de ácido cítrico. Material y métodos: se estudiaron 88 pacientes (49 mujeres y 39 hombres; con promedio de edad 45 ± 15 años, referidos para endoscopia gastrointestinal y toma de biopsias. La PAU-13Cs se realizó en ayuno. Se recolectaron las muestras de aire espirado en tubos de cristal de 10 ml, antes y 30 minutos después de administrar simultáneamente 50 mg de urea-13C y 2 g de ácido cítrico disueltos en 200 ml de agua. Las muestras se analizaron por espectrometría de masas. El diagnóstico de infección se consideró cuando el cultivo y/o la biopsia y serología fueron positivas para H. pylori. Resultados: cincuenta y un pacientes (57,95% fueron positivos, 30 (34,10% negativos para H. pylori y 7 (7,95% casos se consideraron indeterminados. La sensibilidad, especificidad, valor predictivo positivo y negativo de PAU-13Cs fue de 90,2, 93,3, 95,8 y 84,8%, respectivamente. Con exactitud de 91,4%. Conclusión: la administración simultánea de 50 mg de urea-13C y 2 g de ácido cítrico, representa una alternativa para el diagnóstico no invasivo de infección por H. pylori, debido a que conserva la certeza diagnóstica de la PAU-13C.Objective: to validate a simplified 13C-urea breath test (13C-UBT method for the diagnosis of H. pylori infection. Material and methods: patients referred for gastrointestinal endoscopy and biopsy were included, and a 13C-UBT was performed after a 6-hour fast. Breath samples were collected in 10 ml glass tubes before and 30 min after the simultaneous administration of 50 mg of 13C-urea and 2 g of citric acid in 200 ml of water. All breath samples were analyzed using isotope ratio mass spectrometry. The diagnosis of H. pylori infection was established with a positive culture and/or positive

  2. Determination of urea 13C in urea 13C mixed powder by HPLC

    International Nuclear Information System (INIS)

    Zhong Jianguo; Song Tianqi

    2006-01-01

    A HPLC method is developed for determination of Urea 13 C in Urea 13 C Mixed Powder. A Alltech Econosphere NH2 column (250 mm x 4.6 mm, 5 μm)is used as stationary phrase, a mixture of V(acetonitrile): V(methanol): V(water) = 900 : 100: 10 is used as mobile phase and the flow rate is l mL·min -1 , UV detection wavelength is performed at 200 nm. The calibration curve shows good linearity in the range of 0.2-1.0 g·L -1 of Urea 13 C, y=2.548 x 10 6 x + 4.005 x 10 4 , r=0.9999, and the averaged recovery is 100.6%. The method is simple and accurate, and can be used for the quality control of Urea 13C Mixed Powder. (authors)

  3. Synthesis of 13N and/or 11C single or doubly labelled urea

    International Nuclear Information System (INIS)

    Emran, A.M.

    1989-01-01

    Utilization of nitrogen by plants encounters two important problems which are denitrification and deficiency or inactivation of certain enzyme. In the first process the fertilizer is affected by certain bacteria to produce nitrogen or its oxides which cannot be utilized by plants. In the second process, transformation of urea nitrogen into forms usable by plants depends on abundance and activity of the enzyme urease. Study of inorganic nitrogen transport has been underway using 13 N-nitrate as a tracer. Behavior of organic nitrogen can be studied using labelled urea. [ 13 N] and/or [ 11 C] single or doubly labelled urea are good tracers for this purpose. Reaction of trace amounts of potassium cyanate with 13 N-ammonium sulfate produced 13 N-ammonium cyanate which was thermally transformed into [ 13 N]-urea with no added carrier. Similarly, [ 11 C]-potassium cyanate reacted with 13 N-ammonium sulfate to produce 13 N/ 11 C-doubly labelled urea. Thin layer and high performance liquid chromatography were used to identify the products and determine the yields

  4. Comparison of Accuracy Between 13C- and 14C-Urea Breath Testing: Is an Indeterminate-Results Category Still Needed?

    Science.gov (United States)

    Charest, Mathieu; Bélair, Marc-André

    2017-06-01

    Helicobacter pylori infection is the leading cause of peptic ulcer disease. The purpose of this study was, first, to assess the difference in the distribution of negative versus positive results between the older 14 C-urea breath test and the newer 13 C-urea breath test and, second, to determine whether use of an indeterminate-results category is still meaningful and what type of results should trigger repeated testing. Methods: A retrospective survey was performed of all consecutive patients referred to our service for urea breath testing. We analyzed 562 patients who had undergone testing with 14 C-urea and 454 patients who had undergone testing with 13 C-urea. Results: In comparison with the wide distribution of negative 14 C results, negative 13 C results were distributed farther from the cutoff and were grouped more tightly around the mean negative value. Distribution analysis of the negative results for 13 C testing, compared with those for 14 C testing, revealed a statistically significant difference between the two. Within the 13 C group, only 1 patient could have been classified as having indeterminate results using the same indeterminate zone as was used for the 14 C group. This is significantly less frequent than what was found for the 14 C group. Discussion: Borderline-negative results do occur with 13 C-urea breath testing, although less frequently than with 14 C-urea breath testing, and we will be carefully monitoring differences falling between 3.0 and 3.5 %Δ. 13 C-urea breath testing is safe and simple for the patient and, in most cases, provides clearer positive or negative results for the clinician. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  5. 13C-urea breath test analyzed with infrared isotope spectrometry for the diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Dahlberg, M.; Schoensby, H.

    1998-01-01

    The authors have evaluated a 13 C-urea breath test for the diagnosis of Helicobacter pylori infection. The 13 C-test was analyzed with isotope-selective non-dispersive infrared spectrometry and compared with a 14 C-urea breath test and the urease test in gastric mucosal biopsies. 46 patients were analyzed with breath tests, 23 patients were negative and 22 patients were positive with both methods. One patients was positive with 14 C-method and negative with the 13 C-urea breath test. 61 patients were analyzed with the 13 C-urea breath test and the urease test. 30 patients were negative and 30 patients were positive with both methods, whereas one patient with a negative urease test had a positive breath test. 13 C-urea breath test analyzed with isotope-selective non-dispersive infrared spectrometry is a fast, simple, non-radioactive, non-invasive, convenient and reliable method for the diagnosis of Helicobacter pylori infection. 12 refs., 2 figs., 1 tab

  6. Hyperpolarized 13C Urea Relaxation Mechanism Reveals Renal Changes in Diabetic Nephropathy

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Stokholm Nørlinger, Thomas; Christoffer Hansen, David

    2016-01-01

    Purpose: Our aim was to assess a novel 13C radial fast spin echo golden ratio single shot method for interrogating early renal changes in the diabetic kidney, using hyperpolarized (HP) [13C,15N2]urea as a T2 relaxation based contrast bio-probe. Methods: A novel HP 13C MR contrast experiment...... saturation level and the relaxation times were observed in the healthy controls. Conclusion: HP [13C,15N2]urea apparent T2 mapping may be a useful for interrogating local renal pO2 status and renal tissue alterations....

  7. Hyperpolarized 13C-Urea MRI for the assessment of the urea gradient in the porcine kidney

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Stewart, Neil James; Wild, Jim Michael

    Renal anatomical and pathophysiological alterations are directly associated with the fluid and electrolyte balance in the kidney, which is regulated by the extracellular corticomedullary osmolality gradient. We introduce a novel magnetic resonance imaging (MRI) approach to monitor...... treatment resulted in an increased urea accumulation in the cortical space. This work demonstrates intra-renal functional assessment with hyperpolarized 13C-urea MRI in multi-papillary kidneys....

  8. Minimal sampling protocol for accurate estimation of urea production: a study with oral [13C]urea in fed and fasted piglets

    NARCIS (Netherlands)

    Oosterveld, Michiel J. S.; Gemke, Reinoud J. B. J.; Dainty, Jack R.; Kulik, Willem; Jakobs, Cornelis; de Meer, Kees

    2005-01-01

    An oral [13C]urea protocol may provide a simple method for measurement of urea production. The validity of single pool calculations in relation to a reduced sampling protocol was assessed. In eight fed and five fasted piglets, plasma urea enrichments from a 10 h sampling protocol were measured

  9. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    The metabolically inactive hyperpolarized agents HP001 (bis-1,1-(hydroxymethyl)-[1-13C]cyclopropane-d8) and urea enable a new type of perfusion magnetic resonance imaging based on a direct signal source that is background-free. The addition of perfusion information to metabolic information obtained...... (T1=95 s ex vivo, 32 s in vivo at 3 T) using a pulse sequence with balanced steady-state free precession and ramped flip angle over time for efficient utilization of the hyperpolarized magnetization and three-dimensional echo-planar spectroscopic imaging of urea copolarized with [1-13C...... of separate dynamic HP001 imaging and copolarized pyruvate/urea imaging were compared. A strong and significant correlation (R=0.73, P=.02) detected between the urea and HP001 data confirmed the value of copolarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism....

  10. GC-MS DETERMINATION OF RATIOS OF STABLE-ISOTOPE LABELED TO NATURAL UREA USING [(CN2)-C-13-N-15]UREA FOR STUDYING UREA KINETICS IN SERUM AND AS A MEANS TO VALIDATE ROUTINE METHODS FOR THE QUANTITATIVE ASSAY OF UREA IN DIALYSATE

    NARCIS (Netherlands)

    WOLTHERS, BG; TEPPER, T; WITHAG, A; NAGEL, GT; DEHAAN, THY; VANLEEUWEN, JJ; STEGEMAN, CA; HUISMAN, RM

    A GC-MS determination of urea in serum or spent dialysate is described, using (CN2)-C-13-N-15-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative

  11. Gastric MALT lymphoma: clinical characteristics and prevalence of H. pylori infection in a series of 37 cases Linfoma MALT gástrico: características clínicas y prevalencia de la infección por H. pylori en una serie de 37 casos

    Directory of Open Access Journals (Sweden)

    J. P. Gisbert

    2006-09-01

    en nuestro hospital durante los últimos 15 años. Métodos: se identificaron retrospectivamente todos los pacientes diagnosticados de linfoma MALT gástrico en nuestro centro en los últimos 15 años. Se revisaron las variables demográficas, clínicas, analíticas, endoscópicas, histológicas, el estudio de extensión, la estadificación y la infección por H. pylori. Resultados: se identificaron 37 pacientes con linfoma MALT gástrico, con una edad media de 61 años, el 62% varones. El síntoma de presentación más frecuente fue la dispepsia (76%, seguido de la hemorragia digestiva alta (11% y el síndrome constitucional (8%. Durante la endoscopia se identificaron lesiones erosivas en el 41% y proliferativas/exofíticas en el 43%. La mayoría de los linfomas fueron de bajo grado (68%. Estadificación: EI (56%, EII (13%, EIII (3% y EIV (28%. La prevalencia de H. pylori (histología en todos los casos, test rápido de la ureasa en el 19% y prueba del aliento con 13C-urea en el 24% fue del 46%. Cuando únicamente se consideraron los linfomas de bajo grado en estadio EI, la prevalencia de H. pylori ascendió al 55%. Cuando la presencia de H. pylori se valoró mediante la prueba del aliento (además de la histología, la prevalencia de infección ascendió al 78%. Conclusiones: es probable que la reducida prevalencia de infección por H. pylori encontrada en algunos estudios, como el nuestro, sea debida a resultados falsos negativos obtenidos al utilizar un sólo test diagnóstico, por lo que se sugiere el empleo de al menos dos, e incluso añadir un método diagnóstico "no invasivo' como la prueba del aliento con 13C-urea antes de excluir definitivamente la infección por H. pylori.

  12. An electron spin resonance study on the gamma-irradiation of urea, urea- d4, 1-3-dimethylurea, 1-3-diethylurea and 1,1',3,3'-tetramthylurea

    International Nuclear Information System (INIS)

    Kang, Y.S.; McManus, H.J.D.; Kevan, L.

    1994-01-01

    Urea, urea-d 4 , 1,3-dimethylurea, 1,3-diethylurea powder and 1,1',3,3'-tetramethylurea, and their solutions in D 2 O were γ-irradiated with 0.0882 kGy both at room temperature and at 77 K. The product radicals were identified with X-band electron spin resonance, based on the g-factor and hyperfine coupling constants. The radicals formed from urea and urea-d 4 were identified as nitrogen-centered and resulted from N-H bond dissociation. The radicals produced from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as carbon-centered and resulted from C-H bond cleavage. The electron spin resonance signals of 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea are similar in both the powder and D 2 O solution. The radicals observed from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as . NH-CH 2 , . NH-CHCH 3 and . (CH 3 )(CH 2 ), respectively. (author)

  13. Application of 13C-urea breath test in patients diagnosed as H. pylori-negative by gastroscopy

    International Nuclear Information System (INIS)

    Li Long; Liu Changjiang; Gao Jianqing; Xu Sumei; Chen Linna; Zhou Jianming

    2006-01-01

    13 C-urea breath test( 13 C-UBT)was used to evaluate infection rate of H. pylori(HP) and effect of HP eradication in patients diagnosed as HP-negative by histology and rapid urease test. Patiens without gastrointestinal disorders were set as control group. Within 640 patients diagnosed as HP-negative by histology and rapid urease test, there were 389 patients showed HP-positive by 13 C-UBT. The positive rate of HP was 60.8%. 389 patients diagnosed as HP- positive by 13 C-UBT were treated with PPI-based triple therapy, PPI-based double therapy and single PPI therapy, respectively. After treatment, the negative rate of 13 C-UBT was 83.8%, 18.4% and 3.3%, respectively. The results showed significant difference between three kinds of therapy (P 13 C-UBT could improve the diagnostic rate of HP to patients who diagnosed as HP-negative by histology and rapid urease test. (authors)

  14. Turnover of carbon in the 13C-urea breath test for the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos

    2013-01-01

    To obtain a standard protocol for the application of 13 C-urea breath test ( 13 C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of 13 C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the 13 C in the 13 C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio 13 C/ 12 C in expired CO 2 from patients infected with H. pylori and subjected to 13 C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  15. Turnover of carbon in the {sup 13}C-urea breath test for the detection of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos, E-mail: vladimir@ibb.unesp.br, E-mail: ducatti@ibb.unesp.br, E-mail: mariana.andreazazi@gmail.com, E-mail: caiocury@hotmail.com, E-mail: juniorbassett@hotmail.com, E-mail: mariar@fmb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2013-07-01

    To obtain a standard protocol for the application of {sup 13}C-urea breath test ({sup 13}C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of {sup 13}C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the {sup 13}C in the {sup 13}C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio {sup 13}C/{sup 12}C in expired CO{sub 2} from patients infected with H. pylori and subjected to {sup 13}C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  16. Synthesis and quality control of {sup 13}C-enriched urea for Helicobacter pylori (HP) diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Sant Ana Filho, Carlos R.; Tavares, Claudineia R.O.; Ferreira, Andre V.; Prestes, Cleber V.; Bendassolli, Jose A., E-mail: jab@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-08-01

    The aim of the study was to synthesize the urea ({sup 13}CO(NH{sub 2}){sub 2}), with 99% {sup 13}C atoms, and to perform a quality analysis for the diagnosis (breath test) of Helicobacter pylori. Furthermore, the process was submitted to economic analysis. The reaction was performed in a stainless steel reactor, lined with polytetrafluoroethylene, under low pressure and temperature. The synthesis method was shown to be appropriate (2.35 g; 81.9% yield), evidenced by physico-chemical and microbiological results, according to Brazilian legislation. The production and diagnosis costs were competitive compared with national and international market values, rendering this a valuable tool in clinical medicine. (author)

  17. "VALIDATION OF 13C-UREA BREATH TEST WITH NON DISPERSIVE ISOTOPE SELECTIVE INFRARED SPECTROSCOPY FOR THE DIAGNOSIS OF HELICOBACTER PYLORI INFECTION: A SURVEY IN IRANIAN POPULATION"

    Directory of Open Access Journals (Sweden)

    "Davood Beiki

    2005-04-01

    Full Text Available The urea breath test (UBT which is carried out with 13C or 14C labeled urea is one of the most important non invasive methods for detection of Helicobacter pylori infection. Application of 13C-UBT is becoming increasingly popular because of its non radioactive nature which makes it suitable for diagnostic purposes in children and women of child bearing ages. While isotope ratio mass spectrometer (IRMS is generally used to detect 13C in expired breath, this instrument is expensive and recently non dispersive isotope selective infrared (NDIR spectroscopy which is a lower cost technique has been employed as a reliable counterpart for IRMS in small clinics. The aim of this study was to assess the validity of NDIR spectroscopy technique in Iranian population in comparison with histological examination, rapid urease test and 14C-urea breath test as gold standard. Seventy six patients with dyspepsia were underwent 13CUBT for diagnosis of Helicobacter pylori infection. Good agreements were found between the 13C-UBT and gold standard methods. The 13C-UBT showed 100% sensitivity, 97.3% specificity, 97.56% positive predictive value, 100% negative predictive value and 98.65% accuracy. On the basis of these results it could be concluded that 13C-UBT performed with NDIR spectroscopy is a reliable, accurate and non invasive diagnostic tool for detection of Helicobacter pylori infection in the Iranian population.

  18. Diagnosis of Helicobacter pylori infection in patients with bleeding ulcer disease: rapid urease test and histology Diagnóstico mediante endoscopia de la infección por Helicobacter pylori en pacientes con úlcera gastroduodenal y hemorragia digestiva: test rápido de ureasa e histología

    Directory of Open Access Journals (Sweden)

    M. Castro-Fernández

    2004-06-01

    controversias sobre el valor diagnóstico de practicar, en estos pacientes, alguna, ninguna o ambas pruebas diagnósticas. Objetivos: valorar los resultados del test rápido de ureasa y la histología, practicados simultáneamente, en el diagnóstico de infección por Helicobacter pylori (H. pylori en pacientes con úlcera gastroduodenal y hemorragia digestiva. Pacientes y métodos: incluimos 173 pacientes, 98 varones y 75 mujeres, edad media de 62 años (18-88, con hemorragia digestiva por úlcera duodenal (115 o gástrica (58, diagnosticados por endoscopia en las primeras 24 horas del ingreso. Ningún paciente había recibido tratamiento erradicador frente a H. pylori ni consumido inhibidores de la bomba de protones o antibióticos en al menos las dos semanas previas al ingreso. Investigamos la presencia de H. pylori mediante la obtención de dos biopsias antrales, para estudio histológico (hematoxilina-eosina y una o dos biopsias, también antrales, para el test rápido de ureasa. En los casos con test de ureasa e histología negativos se practicó test del aliento con urea marcada con 13C. Consideramos presencia de infección cuando al menos una de las pruebas invasivas o el test del aliento eran positivos y ausencia de infección cuando las dos pruebas invasivas y el test del aliento eran negativos. Resultados: ciento cincuenta y dos pacientes (88% presentaban infección por H. pylori, 104 (90% en el grupo con úlcera duodenal y 48 (83% en el grupo con úlcera gástrica. El test de ureasa resultó positivo en 119 casos (78% y la histología en 112 casos (74%. Con ambos métodos diagnosticamos 134 de los 152 casos (88% (p < 0,05. Ambos métodos fueron positivos en 97 casos y negativos en 39 casos. En 18 de estos 39 casos el test del aliento resultó positivo. Conclusiones: la histología y el test de ureasa tienen un valor diagnóstico similar en la detección de H. pylori en pacientes con úlcera gastroduodenal y hemorragia digestiva. El test de la ureasa, por la rapidez

  19. Accuracy of non-invasive 13C-urea breath test compared to invasive tests for helicobacter pylori detection

    International Nuclear Information System (INIS)

    Bilal, R.; Khaar, B.; Omar, M.; Qureshi, T.Z.; Ahmed, T.; Latif, Z.; Jaffery, I.; Omar, M.

    2007-01-01

    To compare the sensitivity, specificity and Positive Predictive Value (PPV) of histology, Campylobacter-Like Organism (CLO) test, culture and 13C-Urea Breath Test (UBT) for the diagnosis of Helicobacter pylori infection. District Headquarter Hospital, Rawalpindi, Military Hospital, Rawalpindi and Pakistan Institute of Science and Technology (PINSTECH), Nilore, Islamabad from June 2002 to 2003. Three mucosal biopsy specimens were obtained during endoscopy of 90 symptomatic patients. Histology, CLO test and culture were performed on these specimens. Breath samples for 13C-UBT were collected and sent to RIAD, PINSTECH on the same day for isotope ratio mass spectrometry. For analysis purpose, each of the tests was fixed as the gold standard in turn and the others were then compared against it. In addition, any two as well as any three positive tests were then set as the gold standard and the other tests compared against them to calculate the sensitivity, specificity, accuracy and PPV of other tests. Urea breath test had the highest sensitivity, ranging from 95 to 100%, against all the gold standards with specificity ranging from 55 to 100%, whereas the sensitivity of histological examination was around 98% but it had comparatively lower specificity (49-89%). The CLO test had a sensitivity range of 86-100% and specificity of 67-100%. Culture had the minimum sensitivity (59-70%) but had highest specificity (96-100%) against all the gold standards. Age and gender had no effect on p-value of each test or in combination. The urea breath test has shown the highest ability to detect the organism with 95-100% sensitivity in symptomatic individuals and specificity, which is comparable to other tests. (author)

  20. Clinical application of four plasma tumor markers and 13C-urea test in diagnosis of patients with gastric carcinoma

    International Nuclear Information System (INIS)

    Pu Weigang; Tan Jifu; Zhu Jianhua; Yang Yongqing

    2010-01-01

    Objective: To investigate clinical value of plasma gastrin, leptin, carbohydrate antigen 125 (CA125), carbohydrate antigen 72-4 (CA72-4) and 13 C-urea breath test ( 13 C-UBT) in diagnosis of patients with gastric carcinoma. Methods: Radioimmunoassay and enzyme immunosorbent assay were used to determine the plasma gastrin, leptin, CA125 and CA72-4 levels, and helicobacter pylori (HP) infection rate was determined by 13 C-UBT. Compared all the determined results from 126 patients with gastric carcinoma (including 32 cases I-II stage gastric carcinoma, 57 cases III stage gastric carcinoma and 37 cases IV stage gastric carcinoma) and 60 normal controls. Results: The plasma gastrin, CA125 and CA72-4 levels in 126 patients with gastric carcinoma were significantly higher (t=3.125, t=3.159, t=3.788, P 13 C-UBT played a considerable role for diagnosis and therapy. (authors)

  1. Nicotine, acetanilide and urea multi-level 2H-, 13C- and 15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry.

    Science.gov (United States)

    Schimmelmann, Arndt; Albertino, Andrea; Sauer, Peter E; Qi, Haiping; Molinie, Roland; Mesnard, François

    2009-11-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for delta13C and delta15N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: delta2H(nicotine) -162 to -45 per thousand, delta13C(nicotine) -30.05 to +7.72 per thousand, delta15N(nicotine) -6.03 to +33.62 per thousand; delta15N(acetanilide) +1.18 to +40.57 per thousand; delta13C(urea) -34.13 to +11.71 per thousand, delta15N(urea) +0.26 to +40.61 per thousand (recommended delta values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as

  2. Urea recycling from the renal pelvis in sheep: A study with [14C]urea

    International Nuclear Information System (INIS)

    Cirio, A.; Boivin, R.

    1990-01-01

    To test the hypothesis that urea can be recycled from the renal pelvis, [14C]urea diluted in native urine (1 microCi/ml) was perfused (0.5 ml/min) into one of the pelvises of sheep fed either normal (NP) or low (LP)-protein diets. Blood samples were obtained from the ipsilateral renal vein and from the carotid artery throughout the perfusions. 14C activity determinations in urine and plasma demonstrated a flux of [14C]urea from the pelvis to renal vein blood (40,000 in NP and 130,000 disintegrations/min in LP sheep, P less than 0.01). The corresponding flux of native urea was only 1.5 times higher in NP than in LP sheep (6.8 +/- 1.1 vs. 4.7 +/- 2.9 mumol/min, not significant) despite their 8 times higher urinary concentration of urea. The fraction of filtered urea that was reabsorbed in the pelvis was larger in LP sheep (7.5 +/- 3.7 vs. 1.9 +/- 0.7% in NP sheep, P less than 0.05). A fraction of urea is thus actually recycled from the renal pelvis in sheep, and this pelvic retention is enhanced in LP animals. The importance of this phenomenon in the nitrogen economy is discussed

  3. Determination of urea kinetics by isotope dilution with [C-13]urea and gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis

    NARCIS (Netherlands)

    Kloppenburg, Wybe; Wolthers, BG; Stellaard, F; Elzinga, H; Tepper, T; deJong, PE; Huisman, RM

    1. Stable urea isotopes can be used to study urea kinetics in humans, The use of stable urea isotopes far studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material, We devised a urea dilution for measurement of the distribution volume,

  4. O interactions in 1,3-diphenyl-urea

    Indian Academy of Sciences (India)

    The synthesis, X-ray structure and role of intermolecular interactions have been studied in case of 1,3-diphenyl-urea, owing to its medicinal importance. The compound crystallizes in orthorhombic crystal system (space group, 21) with unit cell parameters, = 9.118(3), = 10.558(2), = 11.780(3) Å and = 4.

  5. The fate of ingested [sup 14]C-urea in the urea breath test for Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Munster, D J; Chapman, B A; Burt, M J; Dobbs, B R; Allardyce, R A; Bagshaw, P F; Troughton, W D; Cook, H B [Christchurch Hospital (New Zealand)

    1993-08-01

    The metabolic fate of the radioactive carbon in the [sup 14]C-urea breath test for Helicobacter pylori was investigated in 18 subjects. After ingestion of labelled urea, breath was sampled for 24 h, and urine was collected for 3 days. Subjects were designated high or low expirers on the basis of their breath counts, and this agreed well with H. pylori serologic analyses. When given 185 or 37 kBq of [sup 14]C-urea, 51% of the label was recovered from the breath of high expirers, and 7% from the breath of low expirers. The mean combined urinary and breath recovery for high expirers was 86%, and for low expirers it was 97%. It is concluded that the long-term retention of [sup 14]C from ingested [sup 14]C-urea is low. The results enable a more accurate estimation to be made of radiation exposure resulting from the [sup 14]C-urea breath test. 16 refs., 3 figs., 2 tabs.

  6. Nicotine, acetanilide and urea multi-level2H-,13C- and15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry

    Science.gov (United States)

    Schimmelmann, A.; Albertino, A.; Sauer, P.E.; Qi, H.; Molinie, R.; Mesnard, F.

    2009-01-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the S values of these reference materials should bracket the isotopic range of samples with unknown S values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for ??13C and ??13N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: ??2Hnicotine -162 to -45%o, ??13Cnicotine -30.05 to +7.72%, ?? 15Nnicotine -6.03 to +33.62%; ??15N acetanilide +1-18 to +40.57%; ??13Curea -34.13 to +11.71%, ??15Nurea +0.26 to +40.61% (recommended ?? values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as the first organic nitrogen stable isotope reference materials for GC-IRMS that are available with different ??13N

  7. Comparison between the 13C-urea breath test and stool antigen test for the diagnosis of childhood Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Kato, Seiichi; Minoura, Takanori; Iinuma, Kazuie; Konno, Mutsuko; Tajiri, Hitoshi; Matsuhisa, Takeshi

    2004-01-01

    As noninvasive tests for Helicobacter pylori infection, the 13 C-urea breath test (UBT) and stool antigen test have been widely used. In children, however, there are few studies reporting which test shows superior performance. The purpose of this study was to compare the 13 C-UBT and stool antigen test for their accuracy in diagnosing. H. pylori infection in children. A total of 123 Japanese children, ages 2 to 17 years (mean, 12 years) who underwent gastric biopsies for H. pylori infection were studied. The diagnoses included gastritis (n=55), gastric ulcer (n=5), duodenal ulcer (n=20), iron-deficiency anemia (n=7), and other conditions (n=36). The cutoff value of the 13 C-UBT was defined to be 3.5 per mille. The stool antigen test was performed using the H. pylori stool antigen (HpSA) enzyme-linked immunosorbent assay (ELISA) (Premier Platinum HpSA). In 16 patients who received eradication therapy, the 13 C-UBT and HpSA were repeated 2 months after treatment. Based on biopsy tests, 60 children were infected with H. pylori and 63 children were not. For the 13 C-UBT, the sensitivity, specificity, and accuracy were 95.0% (95% confidence interval [CI], 86.1%-99.0%), 98.4% (95% CI, 91.5%-100%), and 96.4% (95% CI, 93.6%-99.9%), respectively. For the HpSA, the sensitivity, specificity, and accuracy were 983.% (95% CI, 90.8%-100%), 98.4% (95% CI, 91.2%-100%), and 98.3% (95% CI, 96.0%-100%), respectively. There were no significant differences between the performance of these two tests. In the assessment of H. pylori eradication, the results of 13 C-UBT and HpSA agreed with those of biopsy tests. The 13 C-UBT and the HpSA are equally accurate for the diagnosis of active H. pylori infection in Japanese children. (author)

  8. 1-(3-Cyano­phen­yl)-3-(2-furo­yl)thio­urea

    Science.gov (United States)

    Theodoro, Jahyr E.; Mascarenhas, Yvonne; Ellena, Javier; Estévez-Hernández, Osvaldo; Duque, Julio

    2008-01-01

    The title compound, C13H9N3O2S, was synthesized from furoyl isothio­cyanate and 3-amino­benzonitrile in dry acetone. The thio­urea group is in the thio­amide form. The thio­urea fragment makes dihedral angles of 3.91 (16) and 37.83 (12)° with the ketofuran group and the benzene ring, respectively. The mol­ecular geometry is stabilized by N—H⋯O hydrogen bonds. In the crystal structure, centrosymmetrically related mol­ecules are linked by two inter­molecular N—H⋯S hydrogen bonds to form dimers. PMID:21202835

  9. Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of 14C acetyl urea

    International Nuclear Information System (INIS)

    Bergner, H.; Kijora, C.; Goersch, R.

    1976-01-01

    2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of 14 C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of 14 C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided. (author)

  10. Fractionation of nitrogen and carbon isotopes by means of urea chromatography

    International Nuclear Information System (INIS)

    Hirschberg, K.; Krumbiegel, P.; Faust, H.

    1981-01-01

    Between aqueous urea solutions and strongly acid cation exchange resins of the polystyrene-sulfoacid type a solid-liquid-phase distribution equilibrium develops with an isotope effect of nitrogen and carbon in urea. The [ 13 C, 15 N] urea molecules are preferably bound to the exchanger matrix. The elementary separation factors for 15 N and 13 C enrichment have been determined to be 1.00 per cent. Column chromatographic separation with the aid of Dowex 50 WX8 renders the preparation of double-labelled urea feasible. (author)

  11. Clinical investigation of 14C-urea breath test

    International Nuclear Information System (INIS)

    Yu Yongli; Zhu Ruisen; Ji Hong; Luo Quanyong

    2000-01-01

    To investigate clinical value of 14 C-urea breath test ( 14 C-UBT) for the diagnosis of Helicobacter pylori(Hp), 70 patients were both performed gastroscopy (taking gastric mucosae biopsy for rapid urease test and histology) and 14 C-UBT (some patients by Hp-IgG or DNAHp test also) within two days. The positive cases of both rapid urease test and histology was defined as 'gold standard' of Hp-positive, whereas the negative cases of both rapid urease test and histology as 'gold standard' of Hp-negative. The sensitivity of 14 C-UBT was 93.2%, the specificity 73.1%, and the diagnostic accuracy 85.7%. The difference (comparing with 'gold standard') was not marked (x 2 = 0.9 0.05(1) 2 = 3.84, P>0.05). But the diagnostic accuracy of 14 C-UBT (85.7%) and Hp-IgG (50%) had a marked difference (x 2 13.80>x 0.01(1) 2 = 6.64, P 14 C-UBT was easy to operate, reliable and suitable for clinical application

  12. Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of /sup 14/C acetyl urea

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, H; Kijora, C; Goersch, R [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

    1976-01-01

    2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of /sup 14/C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of /sup 14/C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided.

  13. Radiation-induced polymerization of 1, 3-butadiene in urea canal complex as studied by broad line NMR

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Hayakawa, Naohiro; Abe, Toshihiko

    1975-01-01

    Dependence of the NMR spectrum on the molar ratio of 1,3-butadiene to urea, temperature dependence of the spectrum and changes of the spectrum during polymerization were observed. The results were discussed in comparison with previously reported results for the canal polymerization of acrylonitrile and vinyl chloride. 1,3-butadiene formes a canal complex with the molar ratio of 1 to 4 for 1,3-butadiene to urea. The urea canal complex is decomposed at -15 0 C. The spectrum of 1,3-butadiene in urea canal complex shows existence of a remarkably mobile component which was not observed on the spectra of acrylonitrile - urea of vinyl chloride - urea canal complex. The line width of 1,3-butadiene in the urea canal complex except the very narrow component was broader than that for vinyl chloride in the urea canal complex over an observed temperature range. The line width of urea formed the canal decreases at lower temperature than those of urea in vinyl chloride - urea canal complex. The post-polymerization of 1,3-butadiene in the urea canal complex started clearly from -78 0 C and completes when the temperature was raised to 20 0 C. The polymerization will be proceeded by the such way that monomer molecules move to the active center in the canal, as considered in the case of the polymerization of acrylonitrile and vinyl chloride in the canal complex. The crystal structure of the urea canal was maintained during polymerization and than the polybutadiene - urea canal complex was necessarily formed after the polymerization. The formation of the polymer - urea canal complex has distinct difference between 1,3-butadiene and acrylonitrile or vinyl chloride. For acrylonitrile and vinyl chloride the canals around the polymer formed are destroyed. The structure of polybutadiene - urea canal complex was hexagonal having a=8.21, c=10.50 A. (auth.)

  14. Preparation of 14C-labelled urea for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    Jiang Bingsheng

    2001-01-01

    The preparation of 14 C-urea from [ 14 C]-barium carbonate is reported. The results show that chemical yield can reach 80% (average of 6 runs); melt point is 132 - 136 degree C; purity is 99.65% - 99.85%. After being analyzed by IR, UV, NMR, MS, and elemental analysis, the 14 C-urea has the same molecular structure as that of standard urea. Animal trial indicates that clinical use is safe. Good stability is shown by stability testing under different luminous flux, temperature and relative humidity

  15. Biodisponibilidad de fósforo en un suelo del sur de Santa Fe (Argentina: Efectos de dos fuentes fosfatadas y sus mezclas con urea Phosphorus bioavailability in a soil of the south of Santa Fe (Argentina: Effects of two phosphate sources and their mixtures with urea

    Directory of Open Access Journals (Sweden)

    M. M. Silva Rossi

    2006-12-01

    Full Text Available Los objetivos de este trabajo fueron: i determinar en qué medida las fuentes fosfatadas y sus mezclas con urea afectan la biodisponibilidad de P, ii analizar los efectos de interacción urea/fuente fosfatada, y iii analizar el efecto de la urea sobre el P nativo del suelo. El experimento se condujo en un Hapludol típico Serie Santa Isabel (pH 6,1; 29 g kg-1 de materia orgánica; 12,4 mg kg-1 de P extractable; P total, 446 mg kg-1; MBC 35,8 L kg-1. Se hicieron ensayos de fertilización de trigo con dos fuentes fosfatadas: fosfato monoamónico y fosfato diamónico en dosis de 0, 9 y 17 kg P/ha, en mezclas físicas con urea en dosis de 0, 19 y 37 kg N/ha. Se concluyó que la aplicación de urea no causa efectos sobre los tenores de fósforo nativo en la zona de aplicación. Además, la disponibilidad del fósforo aplicado varía con la dosis y fuente fosfatada utilizada: la aplicación de fosfato monoamónico aumenta significativamente la biodisponibilidad del nutriente en este suelo, con respecto al fosfato diamónico. La utilización de mezclas de fertilizantes fosfatados, con bajas dosis de urea, aumenta la biodisponibilidad del nutriente para el trigo, con relación a las aplicaciones fosfatadas puras.The aims of this work were: i to determine to what extent the phosphorus sources and the mixtures with urea affect P bioavailability, ii to test interaction of urea/phosphate- source effects, and iii to test the effect of urea on the native P of the soil . The experiment was performed in a Santa Isabel Typic Hapludoll (soil organic matter: 29 g kg-1; pH: 6.1; extractable P: 12.4 mg kg-1; and total P: 446 mg kg-1; CBM 35.8 L kg-1. Fertilization assays of wheat with two phosphate sources were carried out: monoammonium phosphate and diammonium phosphate in rates of 0. 9 and 17 kg P/ha, in physical mixtures with urea in rates of 0. 19 and 37 kg N/ha. It was concluded that in the soil tested, the use of urea causes no effects on the native phosphorus

  16. The synthesis of no-carrier-added [11C]urea from [11C]carbon dioxide and application to [11C]uracil synthesis

    International Nuclear Information System (INIS)

    Chakraborty, P.K.; Mangner, T.J.; Chugani, H.T.

    1997-01-01

    No-carrier-added [ 11 C]urea has been synthesized by bubbling cyclotron-produced [ 11 C]-carbon dioxide directly into a tetrahydrofuran solution of lithium bis(trimethylsilyl)amide, followed by hydrolysis of the C-11 labeled adduct with aqueous ammonium chloride. Using this simple, one-pot method, [ 11 C]urea was produced in 55-70% radiochemical yield (decay-corrected) in 16 min following end-of-bombardment (or in 10 min following the introduction of the [ 11 C]carbon dioxide. The [ 11 C]urea thus produced was converted to [ 11 C]uracil (carrier-added) in 40-75% decay-corrected radiochemical yield by condensation with diethyl malate in presence of fuming sulfuric acid. (author)

  17. 14C-urea breath test for the detection of Helicobacter pylori

    NARCIS (Netherlands)

    Veldhuyzen van Zanten, S. J.; Tytgat, K. M.; Hollingsworth, J.; Jalali, S.; Rshid, F. A.; Bowen, B. M.; Goldie, J.; Goodacre, R. L.; Riddell, R. H.; Hunt, R. H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14C-urea breath test which uses 5 microCi 14C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared

  18. Reassessment of primed constant-infusion tracer method to measure urea kinetics

    International Nuclear Information System (INIS)

    Jahoor, F.; Wolfe, R.R.

    1987-01-01

    The validity of the primed constant-infusion tracer technique to make short-term measurements of urea production rates (R/sub a/) in humans in a physiological steady state and during disruption of steady state was evaluated. Four subjects received a primed constant infusion (P/I = 560 min) of [ 13 C]urea for 8 h. A plateau in urea enrichment was reached after 2 h and maintained throughout. When [ 13 C]- and [ 18 O]urea were simultaneously infused into four subjects at P/I ratios of 560:1 and 360:1, respectively, both tracers reached plateau enrichment at the same time (2-4 h). The enrichment at plateau was a function of the infusion rate rather than the priming dose, and calculated urea R/sub a/ was the same with either prime. In five additional experiments the technique responded acutely to a physiological perturbation (alanine infusion) in a dose-dependent manner. The results confirm that this technique is appropriate for short-term measurements of urea R/sub a/, and the requirement for accuracy in estimating the priming dose is not impractically stringent

  19. Clinical value of 13C-UBT diagnosing infection of the Hp

    International Nuclear Information System (INIS)

    Xu Changde; Chen Shaoliang; Liu Wenguan

    2004-01-01

    100 dyspeptic patients are performed an endoscopy with biopsy for histology, rapid urease test, 13 C-urea breath test( 13 C-UBT) and ASSURE TM Hp rapid Test(HpRT). Patients are considered to be infected if both histology and biopsies yield positive results, and not infected when both tests are negative. The pathology and persons responsible for endoscopy, urease test and 13 C-UBT are unaware of the results from the other diagnostic methods. The 13 C-UBT has the following results: sensitivity 96% ,specificity 95%; rapid urease test has the following results: sensitivity 79%, specificity 76%; HpRT has the following results: sensitivity 86%, specificity 88%. 13 C-UBT provides excellent sensitivity and specificity for the diagnosis of Hp. Pylori infected Hp, it can be the first choice for detecting the infection of the Hp. (authors)

  20. Degradation mechanism and thermal stability of urea nitrate below the melting point

    International Nuclear Information System (INIS)

    Desilets, Sylvain; Brousseau, Patrick; Chamberland, Daniel; Singh, Shanti; Feng, Hongtu; Turcotte, Richard; Anderson, John

    2011-01-01

    Highlights: → Decomposition mechanism of urea nitrate. → Spectral characterization of the decomposition mechanism. → Thermal stability of urea nitrate at 50, 70 and 100 o C. → Chemical balance of decomposed products released. - Abstract: Aging and degradation of urea nitrate below the melting point, at 100 o C, was studied by using thermal analysis and spectroscopic methods including IR, Raman, 1 H and 13 C NMR techniques. It was found that urea nitrate was completely degraded after 72 h at 100 o C into a mixture of solids (69%) and released gaseous species (31%). The degradation mechanism below the melting point was clearly identified. The remaining solid mixture was composed of ammonium nitrate, urea and biuret while unreacted residual nitric and isocyanic acids as well as traces of ammonia were released as gaseous species at 100 o C. The thermal stability of urea nitrate, under extreme storage conditions (50 o C), was also examined by isothermal nano-calorimetry.

  1. Validation of 14 C-urea breath test for diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio

    1999-01-01

    The aim of this study was to validate the 14 C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of 14 C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p 14 C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  2. Urea metabolism in Barbari kids d on urea molasses diets

    International Nuclear Information System (INIS)

    Lal, M.; Singh, U.B.; Verma, D.N.; Ranjhan, S.K.

    1974-01-01

    The entry rates of urea into the body pool of urea were estimated in Barbari kids using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine output over 24 h and urea content. (M.G.B.)

  3. Optoacoustic 13C-breath test analyzer

    Science.gov (United States)

    Harde, Hermann; Helmrich, Günther; Wolff, Marcus

    2010-02-01

    The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2 isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.

  4. 14C-urea breath test for the detection of Helicobacter pylori

    International Nuclear Information System (INIS)

    Veldhuyzen van Zanten, S.J.; Tytgat, K.M.; Hollingsworth, J.; Jalali, S.; Rshid, F.A.; Bowen, B.M.; Goldie, J.; Goodacre, R.L.; Riddell, R.H.; Hunt, R.H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14 C-urea breath test which uses 5 microCi 14 C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared the outcome of the breath test to the results of histology and culture of endoscopically obtained gastric biopsies in 84 patients. The breath test discriminated well between the 50 positive patients and the 34 patients negative for Helicobacter pylori: the calculated sensitivity was 100%, specificity 88%, positive predictive value 93%, and negative predictive value 100%. Treatment with bismuth subsalicylate and/or ampicillin resulted in lower counts of exhaled 14 CO 2 which correlated with histological improvement in gastritis. The 14 C-urea breath test is a better gold standard for the detection of Helicobacter pylori than histology and/or culture

  5. Urea metabolism in buffalo calves fed on rations containing two levels of crude protein

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.; Lal, M.; Varma, A.; Ranjhan, S.K.

    1974-01-01

    Urea entry rates into the body pools of Murrah Buffalo calves have been estimated using a single injection isotope dilution technique using 14 C-urea. The animals were fed two levels of crude proteins, namely, 13 percent lower and 19 percent higher than N.R.C. recommendations. Results show that the recycling of urea is significantly better in animals given low crude protein contents. (M.G.B.)

  6. Detection of Helicobacter pylori in rural school children using 13C ...

    African Journals Online (AJOL)

    ulcer, gastric ulcer, non-ulcer dyspepsia and gastritis. Several diagnostic methods are available for the detection of H. pylori, with direct methods based on gastric biopsies. The 13C- Urea Breath Test (UBT) used in this study has advantage over the other methods in that, it is easy to perform, specific (100%), highly sensitive ...

  7. The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection

    International Nuclear Information System (INIS)

    Surveyor, I.; Goodwin, C.S.; Mullan, B.P.; Geelhoed, E.; Warren, J.R.; Murray, R.N.; Waters, T.E.; Sanderson, C.R.

    1989-01-01

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14 C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14 C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14 C-urea in 24 patients with negative microbiological results was 6.9±4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and 14 C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14 C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab

  8. FORTIFICACIÓN DE PULPA DE UCHUVA CON CALCIO, OLIGOFRUCTOSA Y VITAMINA C, ESTABILIZADA CON HIDROCOLOIDE

    Directory of Open Access Journals (Sweden)

    ALBA LUCIA DUQUE

    2014-06-01

    Full Text Available La pulpa de uchuva fortificada con calcio, oligofructosa y vitamina C es un alimento funcional con grandes beneficios para la salud. Para ello se le adicionó componentes biológicamente activos, como ácidos grasos, fibra alimentaria y antioxidantes. En este trabajo se estudió la estabilidad de la pulpa enriquecida en diferentes formulaciones, teniendo en cuenta los criterios de incorporación de calcio y vitamina C (20% del valor diario recomendado VDR y para la oligofructosa (fibra dietaría en relación 1:1 con el calcio. Los resultados obtenidos mostraron que la pulpa de uchuva fortificada con CMC, ologofructosa, calcio y vitamina C presentó en promedio una estabilidad de 87,7±10,0; una viscosidad de 22,8±7,9; una aw de 0,9863±0; pH de 3,3±0,1; acidez de 1,6±0,1; grados Brix de 13,3±0,7; una densidad de 1,32±0 g/mL y las mejores respuestas sensoriales en cuanto a color, aroma, fluidez y sabor.

  9. Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

    International Nuclear Information System (INIS)

    Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

    1981-01-01

    The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

  10. The microdose rapid 14C urea breath test compares well with the original rapid 14 breath test

    International Nuclear Information System (INIS)

    Bellon, M.S.; Bartholomeusz, F.D.L.; Chatterton, B.E.

    2000-01-01

    Full text: The 14 C urea breath test (CUBT) is a sensitive test used in the detection of H. pylori infection. The rapid 14 CUBT using 185 KBq of 14 C urea showed a sensitivity of 100% when tested in 36 patients. The aim of this study was to compare the results of the 14 CUBT performed following the ingestion of 37KBq microdose 14 C urea capsule (Bicapsule, Trimed) with the earlier method which uses 185 KBq 14 C urea. 19 patients (nine female age 21-52 yrs) were studied. All subjects first underwent a 14 CUBT with the microdose capsule and a single 15 minute post ingestion sample. An hour later the test was repeated but with a dose of 185 KBq 14 C urea in liquid form. A normal result was taken as 2 = 0.92). This is shown above. The Rapid 14 CUBT performed following the microdose capsule whilst reducing patient radiation exposure is an accurate test for the detection of H. pylori. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  11. Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification.

    Science.gov (United States)

    Hansen, Adam E; Andersen, Flemming L; Henriksen, Sarah T; Vignaud, Alexandre; Ardenkjaer-Larsen, Jan H; Højgaard, Liselotte; Kjaer, Andreas; Klausen, Thomas L

    2016-12-01

    Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and

  12. Validation of {sup 14} C-urea breath test for diagnosis of Helicobacter pylori

    Energy Technology Data Exchange (ETDEWEB)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio [Sao Paulo Univ., SP (Brazil). Hospital das Clinicas. Dept. de Gastroenterologia]. E-mail: shiroineko@uol.com.br

    1999-02-01

    The aim of this study was to validate the {sup 14} C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of {sup 14} C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p < 0.0001). At 20 min, the test gave 100% sensitivity and specificity with a cut-off value of 562 cpm. Females were higher expirers than males (p=0.005). {sup 14} C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  13. The 13carbon urea breath test for the diagnosis of Helicobacter pylori infection in subjects with atrophic gastritis: evaluation in a primary care setting

    NARCIS (Netherlands)

    Korstanje, A.; van Eeden, S.; Offerhaus, G. J. A.; Sabbe, L. J. M.; den Hartog, G.; Biemond, I.; Lamers, C. B. H. W.

    2006-01-01

    BACKGROUND: (13)Carbon urea breath testing is reliable to detect current infection with Helicobacter pylori but has been reported to be of limited value in selected patients with atrophic body gastritis or acid-lowering medication. AIM: To evaluate the accuracy of (13)carbon urea breath testing for

  14. The sup 14 C-urea breath-test for the detection of gastric Campylobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Surveyor, I; Goodwin, C S; Mullan, B P; Geelhoed, E; Warren, J R; Murray, R N; Waters, T E; Sanderson, C R [Royal Perth Hospital (Australia)

    1989-10-16

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of {sup 14}C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of {sup 14}C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of {sup 14}C-urea in 24 patients with negative microbiological results was 6.9{plus minus}4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and {sup 14}C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the {sup 14}C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab.

  15. Cells for bioartificial liver devices: the human hepatoma-derived cell line C3A produces urea but does not detoxify ammonia.

    Science.gov (United States)

    Mavri-Damelin, Demetra; Damelin, Leonard H; Eaton, Simon; Rees, Myrddin; Selden, Clare; Hodgson, Humphrey J F

    2008-02-15

    Extrahepatic bioartificial liver devices should provide an intact urea cycle to detoxify ammonia. The C3A cell line, a subclone of the hepatoma-derived HepG2 cell line, is currently used in this context as it produces urea, and this has been assumed to be reflective of ammonia detoxification via a functional urea cycle. However, based on our previous findings of perturbed urea-cycle function in the non-urea producing HepG2 cell line, we hypothesized that the urea produced by C3A cells was via a urea cycle-independent mechanism, namely, due to arginase II activity, and therefore would not detoxify ammonia. Urea was quantified using (15)N-ammonium chloride metabolic labelling with gas chromatography-mass spectrometry. Gene expression was determined by real-time reverse transcriptase-PCR, protein expression by western blotting, and functional activities with radiolabelling enzyme assays. Arginase inhibition studies used N(omega)-hydroxy-nor-L-arginine. Urea was detected in C3A conditioned medium; however, (15)N-ammonium chloride-labelling indicated that (15)N-ammonia was not incorporated into (15)N-labelled urea. Further, gene expression of two urea cycle genes, ornithine transcarbamylase and arginase I, were completely absent. In contrast, arginase II mRNA and protein was expressed at high levels in C3A cells and was inhibited by N(omega)-hydroxy-nor-L-arginine, which prevented urea production, thereby indicating a urea cycle-independent pathway. The urea cycle is non-functional in C3A cells, and their urea production is solely due to the presence of arginase II, which therefore cannot provide ammonia detoxification in a bioartificial liver system. This emphasizes the continued requirement for developing a component capable of a full repertoire of liver function. (c) 2007 Wiley Periodicals, Inc.

  16. EXPERIMENTAL INVESTIGATION OF HEAT STORAGE CHARACTERISTIC OF UREA AND BORAX SALT GRADIENT SOLAR PONDS

    Directory of Open Access Journals (Sweden)

    Hüseyin KURT

    2006-03-01

    Full Text Available Salt gradient solar ponds are simple and low cost solar energy system for collecting and storing solar energy. In this study, heat storage characteristic of urea and borax solutions in the solar pond were examined experimentally. Establishing density gradients in different concentration, variations in the temperature and density profiles were observed in four different experiments. Maximum storage temperatures were measured as 28ºC and 36 ºC for the ponds with urea and borax solution, respectively. The temperature difference between the bottom and the surface of the pond were measured as 13 ºC for urea and 17 ºC for borax- solutions. According to these results, heat storage characteristic of the solar pond with borax solution was found to be better than urea solution.

  17. Contamination by Helicobacter pylori measured by the 13C-urea-breast-test and nutritional status of children with chronic diarrhoea syndrome in Havana city

    International Nuclear Information System (INIS)

    Cabrera, A.; Hernandez-Triana, M.; Sanchez, M.; Herrera, X.; Pawong, M.; Moreno, R.; Reyes, D.; Serrano, G.; Diaz, M.E.; Valencia, M.

    2000-01-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori is discussed in pathogenic relation to gastritis, duodenal ulcer chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94% in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the 13 C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values. This research contract proposes the study of contamination with Hp in Cuban children older than 2 years of age affected by chronic diarrhoea using the 13 C-Urea Breath Test and serological tests for detection of anti-Hp IgG antibodies. Their nutritional

  18. Correlation between the 12C+12C, 12C+13C, and 13C+13C fusion cross sections

    Science.gov (United States)

    Notani, M.; Esbensen, H.; Fang, X.; Bucher, B.; Davies, P.; Jiang, C. L.; Lamm, L.; Lin, C. J.; Ma, C.; Martin, E.; Rehm, K. E.; Tan, W. P.; Thomas, S.; Tang, X. D.; Brown, E.

    2012-01-01

    The fusion cross section for 12C+13C has been measured down to Ec.m.=2.6 MeV, at which the cross section is of the order of 20 nb. By comparing the cross sections for the three carbon isotope systems, 12C+12C, 12C+13C, and 13C+13C, it is found that the cross sections for 12C+13C and 13C+13C provide an upper limit for the fusion cross section of 12C+12C over a wide energy range. After calibrating the effective nuclear potential for 12C+12C using the 12C+13C and 13C+13C fusion cross sections, it is found that a coupled-channels calculation with the ingoing wave boundary condition (IWBC) is capable of predicting the major peak cross sections in 12C+12C. A qualitative explanation for this upper limit is provided by the Nogami-Imanishi model and by level density differences among the compound nuclei. It is found that the strong resonance found at 2.14 MeV in 12C+12C exceeds this upper limit by a factor of more than 20. The preliminary result from the most recent measurement shows a much smaller cross section at this energy, which agrees with our predicted upper limit.

  19. Serosal-to-mucosal urea flux across the isolated ruminal epithelium is mediated via urea transporter-B and aquaporins when Holstein calves are abruptly changed to a moderately fermentable diet.

    Science.gov (United States)

    Walpole, M E; Schurmann, B L; Górka, P; Penner, G B; Loewen, M E; Mutsvangwa, T

    2015-02-01

    Urea transport (UT-B) proteins are known to facilitate urea movement across the ruminal epithelium; however, other mechanisms may be involved as well because inhibiting UT-B does not completely abolish urea transport. Of the aquaporins (AQP), which are a family of membrane-spanning proteins that are predominantly involved in the movement of water, AQP-3, AQP-7, and AQP-10 are also permeable to urea, but it is not clear if they contribute to urea transport across the ruminal epithelium. The objectives of this study were to determine (1) the functional roles of AQP and UT-B in the serosal-to-mucosal urea flux (Jsm-urea) across rumen epithelium; and (2) whether functional adaptation occurs in response to increased diet fermentability. Twenty-five Holstein steer calves (n=5) were assigned to a control diet (CON; 91.5% hay and 8.5% vitamin and mineral supplement) or a medium grain diet (MGD; 41.5% barley grain, 50% hay, and 8.5% vitamin and mineral) that was fed for 3, 7, 14, or 21 d. Calves were killed and ruminal epithelium was collected for mounting in Ussing chambers under short-circuit conditions and for analysis of mRNA abundance of UT-B and AQP-3, AQP-7, and AQP-10. To mimic physiologic conditions, the mucosal buffer (pH 6.2) contained no urea, whereas the serosal buffer (pH 7.4) contained 1 mM urea. The fluxes of (14)C-urea (Jsm-urea; 26 kBq/10 mL) and (3)H-mannitol (Jsm-mannitol; 37 kBq/10 mL) were measured, with Jsm-mannitol being used as an indicator of paracellular or hydrophilic movement. Serosal addition of phloretin (1 mM) was used to inhibit UT-B-mediated urea transport, whereas NiCl2 (1 mM) was used to inhibit AQP-mediated urea transport. Across treatments, the addition of phloretin or NiCl2 reduced the Jsm-urea from 116.5 to 54.0 and 89.5 nmol/(cm(2) × h), respectively. When both inhibitors were added simultaneously, Jsm-urea was further reduced to 36.8 nmol/(cm(2) × h). Phloretin-sensitive and NiCl2-sensitive Jsm-urea were not affected by diet. The

  20. 21 CFR 184.1923 - Urea.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea. 184.1923 Section 184.1923 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1923 Urea. (a) Urea (CO(NH2)2, CAS Reg. No. 57-13-6) is the diamide of...

  1. ACUTE RENAL FAILURE WITH NORMAL PLASMA UREA LEVEL SECONDARY TO ACUTE PYELONEPHITIS IN A SINGLE KIDNEY PATIENT

    Directory of Open Access Journals (Sweden)

    Imperiali N

    2006-03-01

    Full Text Available SUMMARYAcute renal failure is a syndrome that usually runs with an increase in creatinine and urea plasma levels. However, there are clinical situations in which this syndrome may run with an increase in plasma creatinine keeping normal the urea one.In this report we present a case of acute renal failure with normal plasma urea level secondary to an acute pyelonephritis in a single kidney patient. The patient had an increased fractional excretion of urea which could explain the normal plasma urea levels found despite of his reduced glomerular filtration. This increased urea excretion state was interpreted as a consequence of the nephrogenic diabetes insipidus and alteration of the intra-renal urea reciclying process that the acute pyelonephritis induced. In conclusion: Acute pyelonephritis in a single kidney patient can appear as a pattern of acute renal failure with normal plasma urea levels. RESUMEN:La insuficiencia renal aguda es un sindrome que característicamente cursa con niveles plasmáticos elevados de urea y creatinina. Sin embargo, hay situaciones clínicas en las cuales este sindrome puede cursar con un incremento de la creatininemia sin presentar elevación de la uremia.En este reporte presentamos un caso clínico de una insuficiencia renal aguda con uremia normal secundaria a una pielonefritis aguda en un paciente con riñón único. El paciente presentaba una elevada excreción fraccional de urea lo cual podía explicar su uremia normal pese a estar cursando una caída del filtrado gomerular. Dicha excreción de urea elevada fue interpretada como secundaria a una diabetes insipida nefrogénica y una alteración en el recirculado intra-renal de la urea ambos producto de la pielonefritis aguda. Concluimos que la pielonefritis aguda en un paciente mono-reno puede presentarse con un patrón de insuficiencia renal aguda con uremia normal.

  2. ACUTE RENAL FAILURE WITH NORMAL PLASMA UREA LEVEL SECONDARY TO ACUTE PYELONEPHITIS IN A SINGLE KIDNEY PATIENT

    Directory of Open Access Journals (Sweden)

    Algranati L

    2007-04-01

    Full Text Available SUMMARY: Acute renal failure is a syndrome that usually runs with an increase in creatinine and urea plasma levels. However, there are clinical situations in which this syndrome may run with an increase in plasma creatinine keeping normal the urea one. In this report we present a case of acute renal failure with normal plasma urea level secondary to an acute pyelonephritis in a single kidney patient. The patient had an increased fractional excretion of urea which could explain the normal plasma urea levels found despite of his reduced glomerular filtration. This increased urea excretion state was interpreted as a consequence of the nephrogenic diabetes insipidus and alteration of the intra-renal urea reciclying process that the acute pyelonephritis induced. In conclusion: Acute pyelonephritis in a single kidney patient can appear as a pattern of acute renal failure with normal plasma urea levels.RESUMEN: La insuficiencia renal aguda es un sindrome que característicamente cursa con niveles plasmáticos elevados de urea y creatinina. Sin embargo, hay situaciones clínicas en las cuales este sindrome puede cursar con un incremento de la creatininemia sin presentar elevación de la uremia. En este reporte presentamos un caso clínico de una insuficiencia renal aguda con uremia normal secundaria a una pielonefritis aguda en un paciente con riñón único. El paciente presentaba una elevada excreción fraccional de urea lo cual podía explicar su uremia normal pese a estar cursando una caída del filtrado gomerular. Dicha excreción de urea elevada fue interpretada como secundaria a una diabetes insipida nefrogénica y una alteración en el recirculado intra-renal de la urea ambos producto de la pielonefritis aguda. Concluimos que la pielonefritis aguda en un paciente mono-reno puede presentarse con un patrón de insuficiencia renal aguda con uremia normal.

  3. Metabolism of 14C-labelled urea in conventional, germ-free and mono-associated rats

    International Nuclear Information System (INIS)

    Juhr, N.C.; Franke, J.

    1987-01-01

    This report deals with the utilization of 14 C-labelled urea in conventional, defined associated and germ-free rats. With conventional animals 71.44% of the administered 14 C dose can be demonstrated in the exhaled air, 0.47% in organs and 27.35% in the urine. 1.04% were found in the intestinal and fecal contents. Animals mono-associated with Proteus mirabilis have nearly the same utilization rate (59.15, 0.34, 35.98, 2% resp.). In germ-free animals 1.21% of the activity appeared in the exhaled air and showed a small part of non-enzymatic hydrolysis of urea. The excretion of 97.70% in the urine shows, that urea is absorbed from the intestine in germ-free animals. (author)

  4. Comparison of the Quantitative Values of C-14 and C-13 UBT to Reflect the Presence and Degree of Ongoing Helicobacter pylori Infection

    International Nuclear Information System (INIS)

    Lim, Seok Tae; Kim, Dong Wook; Jeong, Hwan Jeong; Sohn, Myung Hee

    2008-01-01

    A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled CO 2 . We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastroduodenoscopic biopsies (GBx) in the same patients. Thirty eight patients (M:F=28:10, age 53.4±13.0 yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (≥200 dpm), intermediate (50∼199 dpm) or negative (<50 dpm). For the C-13 UBT, the results were classified as positive (≥2.5) or negative (<2.5). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p<0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT more

  5. Comparison of the Quantitative Values of C-14 and C-13 UBT to Reflect the Presence and Degree of Ongoing Helicobacter pylori Infection

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Seok Tae; Kim, Dong Wook; Jeong, Hwan Jeong; Sohn, Myung Hee [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2008-06-15

    A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled CO{sub 2}. We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastroduodenoscopic biopsies (GBx) in the same patients. Thirty eight patients (M:F=28:10, age 53.4{+-}13.0 yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive ({>=}200 dpm), intermediate (50{approx}199 dpm) or negative (<50 dpm). For the C-13 UBT, the results were classified as positive ({>=}2.5) or negative (<2.5). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p<0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT

  6. Contamination by Helicobacter pylori measured by the {sup 13}C-urea-breast-test and nutritional status of children with chronic diarrhoea syndrome in Havana city

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, A; Hernandez-Triana, M; Sanchez, M; Herrera, X; Pawong, M; Moreno, R; Reyes, D; Serrano, G; Diaz, M E [Institute of Nutrition and Food Hygiene, Department of Biochemistry and Physiology, Havana (Cuba); Valencia, M [Centro de Investigacion en Alimentacion y Desarrollo, Department of Human Nutrition, Hermosillo, Sonora (Mexico)

    2000-07-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori is discussed in pathogenic relation to gastritis, duodenal ulcer chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94% in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the {sup 13}C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values. This research contract proposes the study of contamination with Hp in Cuban children older than 2 years of age affected by chronic diarrhoea using the {sup 13}C-Urea Breath Test and serological tests for detection of anti-Hp IgG antibodies. Their

  7. Leaching of dieldrin, permethrin, phenyl urea and 4-CL phenyl urea pesticides from soil

    International Nuclear Information System (INIS)

    Onal, G.

    1978-01-01

    Leaching of four 14 C-labelled pesticides (dieldrin, permethrin, phenyl urea and 4-Cl phenyl urea) were investigated. It was found that dieldrin and permethrin were not leached from soil but adsorbed by the soil; phenyl urea and 4-CL phenyl urea were leached to a 7.5 cm depth

  8. Obtención de concentrados de ácidos grasos poliinsaturados por el método de los compuestos de inclusión de urea

    Directory of Open Access Journals (Sweden)

    Robles Medina, A.

    1995-06-01

    Full Text Available A concentration process for polyunsaturated fatty acids (PUFAs n-3 stearidonic (18:4 n-3, eicosapentaenoic (20:5 n-3 and docosahexaenoic (22:6 n-3 from cod liver oil using urea method has been thoroughly studied. The influence of urea/fatty acid ratio and crystallization temperature have been studied on both fatty acids recovery yield and fatty acid concentration. Methanol and ethanol have been used as urea solvent. The use of methanol and an urea/fatty acid ratio of 4:1, and 4°C were found to be the best conditions for SA (concentration 8,5%, yield 71,6 and DHA (59,8% and 100%, respectively. However, 28ºC was found to be the best temperature for EPA (28,7% and 75,6%, respectively. At temperatures below -12ºC, PUFAs also developed adducts compounds, mainly adducts derived from EPA. A variance analysis showed the urea/fatty acid ratio as the main factor affecting fatty acid concentration. At the same time, high urea/fatty acid ratios resulted in increased influence of the solvent used, being more favorable for methanol.

    En este trabajo se estudia la influencia de la relación urea/ácidos grasos y de la temperatura de cristalización (con metanol y etanol como disolventes de la urea sobre las concentraciones y rendimientos en los ácidos grasos estearidónico (SA, 18:4n-3, eicosapentaenoico (EPA, 20:5n-3 y docosahexaenoico (DHA, 22:6n-3, utilizando ácidos grasos de aceite de hígado de bacalao. Las máximas concentraciones y rendimientos en SA (8,5% y 71,6%, respectivamente y en DHA (59,8% y 100% se han obtenido con metanol, una relación urea/ácidos grasos 4:1 p/p y 4°C; sin embargo, si se desean obtener altas concentraciones y rendimientos en EPA es preferible cristalizar a 28ºC (rendimiento 76%, concentración 29%. A temperaturas por debajo de -12°C también los PUFAs forman compuestos de inclusión en un porcentaje elevado, sobre todo el EPA. Mediante un análisis de la varianza se ha puesto de manifiesto que la variable con

  9. Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

    NARCIS (Netherlands)

    Monari, S.; Ranieri, A.; Di Rocco, G.; van der Zwan, G.; Peressini, S.; Tavagnacco, C.; Millo, D.; Borsari, M.

    2009-01-01

    The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three

  10. Simultaneous PET/MRI with 13C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification

    DEFF Research Database (Denmark)

    Hansen, Adam E.; Andersen, Flemming L.; Henriksen, Sarah T.

    2016-01-01

    Background: Integrated PET/MRI with hyperpolarized 13C magnetic resonance spectroscopic imaging (13C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented...... for a clinical whole-body system using simultaneous 1 H-MRI and PET but never for 13C-MRSI and PET. Here, the feasibility of simultaneous PET and 13C-MRSI as well as hyperpolarized 13C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Methods: Combined PET and 13C......-MRSI phantoms including a NEMA [18F]-FDG phantom, 13C-acetate and 13C-urea sources, and hyperpolarized 13C-pyruvate were imaged repeatedly with PET and/or 13C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET...

  11. Ceba de toros con dietas basadas en hollejos de cítrico frescos o conservados Bull fattening with diets based on fresh or preserved citrus pulp

    Directory of Open Access Journals (Sweden)

    F Ojeda

    2012-12-01

    Full Text Available En la Empresa Citrícola "Victoria de Girón", provincia de Matanzas, Cuba, se realizó durante 138 días una investigación con 433 toros de genotipos mestizos de razas lecheras (Holstein x Cebú, en la que se evaluó una dieta basada en pastoreo restringido (cuatro horas en la mañana, forraje verde y hollejo de cítrico a voluntad, suplementados con heno de gramíneas, sal mineral y North gold. El hollejo de cítricos se ofreció en forma de ensilaje desde el 8 de agosto hasta el 31 de octubre, y en forma fresca desde el 1ro de noviembre hasta el 24 de diciembre. Este último se enriqueció con urea, a razón de 0,04 kg por cada 5 kg de hollejo. En el periodo lluvioso, el forraje presentó los menores porcentajes de MS y los mayores valores de EM y PDIN, con poca variación entre periodos para el PDIE. Los hollejos frescos y ensilados mantuvieron valores análogos a los de otros estudios; el heno tenía baja calidad, y el consumo de forraje fue similar en ambos períodos; los hollejos conservados fueron menos consumidos que los frescos. La ganancia fue mayor con los hollejos conservados (0,593 vs. 0,556 kg/animal/día. Los balances nutricionales indicaron que se cubrieron los requerimientos de MS y EM, aunque en los compuestos nitrogenados se realizó un uso ineficiente debido a que hubo un exceso de PDIE, que no fue corregido mediante la incorporación de urea. En ambos períodos, los mayores porcentajes de aportes de nutrimentos correspondieron al forraje y al hollejo de cítrico en sus dos modalidades. Los índices de conversión tuvieron una mejor respuesta con el ensilaje (13,3 vs. 15,5 kg de MS/kg de ganancia. Se concluye que es factible utilizar los hollejos de cítrico frescos o ensilados; aunque, para incrementar las ganancias y la conversión alimentaria, es necesario aumentar la suplementación proteínica y disponer de alimentos que equilibren las cantidades de PDIN y PDIE en las dietas.At the "Victoria de Girón" Citrus Fruit

  12. Microdose 14C urea breath test for the diagnosis of Helicobacter pylori: a survey in Iranian population

    Directory of Open Access Journals (Sweden)

    Reza Dowlatabadi Bazaz

    2005-01-01

    Full Text Available The carbon -14 urea breath test (UBTis a non-invasive and simple method for the diagnosis of Helicobacter pylori infection. Attempts have been made to use lower doses of 14C-urea in the UBT in order to reduce the radiation risk of the test. The aim of this study was to assess the accuracy of a microdose (1 µCi [37 KBq] 14C-UBT in Iranian population for validation of its diagnostic accuracy against gold standard methods. Eighty and two patients were subjected to upper gastrointestinal endoscopy as well as 14C-UBT in one week. Rapid urease test and histological examinations were used as gold standard. Breath samples were collected 10, 20 and 30 minute after ingestion of 1 µCi of 14C- urea solution and their activities were measured using a scintillation counter and expressed as counts per minute (cpm and disintegration per minute (dpm. Good agreement was observed between the 14C-UBT and gold standard for samples which were collected 20 minutes after 14C-urea administration. The 14CUBT showed 100% sensitivity, 95% specificity, 95.45% positive predictive value, 100% negative predictive value and 97.50% accuracy. The results of this study showed good concordance between the 14C-UBT and invasive methods.

  13. Correlation between dietary nitrogen, level of plasma urea and urea excretion in urine of buffalo calves

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.

    1978-01-01

    Two experiments were conducted with 6 male buffalo calves of Murrah breed, aged 1.5 years, to determine whether blood urea nitrogen and urea excretion in urine were associated with protein intake. The animals were fed different amounts of crude protein in their diet. The levels of urea-N in the blood, excretion of 14 C from urea and urea-N in the urine were estimated. Close relationships were observed between nitrogen intake, blood urea nitrogen and urea excretion in the urine. The observations indicated that blood urea-N and urea excretion in urine could be quantitated with the protein intake. (author)

  14. Synthesis and Characterization of Low Solubility Poly Carbonyl Urea as a Slow Release Fertilizer

    International Nuclear Information System (INIS)

    Liu, Y.; Sun, X.

    2016-01-01

    Low solubility poly carbonyl urea has been successfully synthesized by the reaction of urea with methyl carbamate (MC) under the conditions of potassium carbonate as an initiator. It was characterized by FT-IR, /sup 13/C-NMR, and elemental analyser. In addition, the influences of the quantity of initiator, reaction temperature, reaction time and the molar ratio of starting materials on the conversion are discussed in detail. All those observations suggest that when initiator as 10 wt percent of urea, the reaction temperature 160 Degree C, 6 h, and n(urea):n(MC)=1:10, the reaction conversion rate can reach 78.4 percent. Moreover, the novel procedure is reported for the first time and has a significant N slow release properties, the N release in soil was 80 percent over 30 days. (author)

  15. Urea o pollinaza como suplemento proteico para toretes consumiendo ensilaje de pulpa de pejibaye

    Directory of Open Access Journals (Sweden)

    Carlos Arroyo

    2003-01-01

    Full Text Available Un grupo de 24 toros, con un peso vivo de 382 kg fue aleatorizado en 3 tratamientos: 1. control, pastoreo y ensilaje de pejibaye; 2. pastoreo, ensilaje de pejibaye y pollinaza y 3. pastoreo, ensilaje de pejibaye y urea. Los animales pastoreron mezclas de gramíneas con predominancia de Gamalote (Paspalum fasciculatum. El ensilaje se ofreció al 1% del peso vivo y la fuente proteica en dosis de 3 g de N 100 g-1 de carbohidratos fermentables provenientes del ensilaje; ambos materiales fueron ofrecidos 2 veces al día. El período experimental tuvo una duración de 122 días. Los consumos de ensilaje, pollinaza y urea estuvieron en el rango de 4-5 kg; 1-2 kg y 0,055-0,080 kg en base fresca, respectivamente. La suplementación proteica causó incrementos significativos en la ganancia de peso diaria con respecto al control (0,719 kg contra 1,034 kg y 1,021 kg día-1 de los tratamientos con pollinaza y urea, respectivamente. El peso en canal fue incrementado (P<0,05 en un 10% con respecto al control, sin cuantificarse diferencias entre las fuentes proteicas suplementadas. Se concluye que el ganado para carne puede mejorar su peso cuando se usa ensilaje de pulpa de pejibaye suplementado con urea o gallinaza

  16. Limiting the testing of urea: Urea along with every plasma creatinine test?

    Science.gov (United States)

    Zhang, Gao-Ming; Guo, Xu-Xiao; Zhang, Guo-Ming

    2017-09-01

    We found that it is not necessary to simultaneously detect both creatinine (CREA) and urea until the concentration of CREA is lower than the certain level. To reduce urea testing, we suggest measuring urea only when CREA or estimated glomerular filtration rate (eGFR) exceeds a predetermined limit. CREA and urea data were analyzed consisting of almost all of people age above 65 years old check-up (n=95441) in Shuyang countryside, and inpatients (n=101631), outpatients (n=18474) and Routine Health Check-up (n=20509) in Shuyang People's Hospital. The proportions of elevated urea were derived. The data used in this study was generated from people more than 13 years old in both outpatients and inpatients. When the limits for initiating urea testing were used at 85 μmol/L CREA and 120 mL/min/1.73 m 2 eGFR, the percentage of unnecessary urea test are 94.5% and 64.7% (elderly health check-up), 67.9% and 84.5% (outpatients), 88.5% and 73.2% (inpatients), 92.2% and 81.7% (routine health check-up). The missing rate of urea are 1%, 2.5%, 4.6% and 9.2%, 0.1%, 0.4%, 0.9% and 1.8%, 0.4%, 0.8%, 1.4%, and 2.5%, 0.05%, 0.1%, 1.1%, and 0.8% of ureas exceeding 9.28 mmol/L and 8.3 mmol/L in above each group, respectively. If the CREA≤85 μmol/L or eGFR≥90 mL/min/1.73 m 2 , there is 97.5% urea urea missed is 2.5%. We suggest that the initiating urea testing should be based on the upper limit of Reference Intervals serum CREA of females or a 120 mL/min/1.73 m 2 eGFR limit. Conservatively, the urea testing would be reduced by 65% at least. © 2017 Wiley Periodicals, Inc.

  17. UREA BREATH TEST – ITS ROLE IN DIAGNOSTICS

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    Joško Osredkar

    2004-01-01

    Full Text Available Background. Each year many patients visit their physicians complaining of digestive symptoms, most commonly functional dyspepsia (»indigestion« or gastroesophageal reflux (»heartburn«. However, many patients with abdominal discomfort are actually suffering from gastric or duodenal ulcers that are commonly caused by H. pylori and thus are curable. Clearing the infection usually heals the ulcer and prevents relapse, so an accurate diagnosis is important. There are several options for diagnosing H. pylori infection: serology to detect antibodies against the bacterium; endoscopic biopsy for urease testing (H. pylori produce a urease that breaks down urea to ammonia and carbon dioxide; histology with special stains; or culture. Unfortunately, these procedures are invasive, expensive and not always accurate. Serological tests require a blood sample and tell only that a patient has been exposed to H. pylori at some time in the past, but not whether the patient is currently infected. Endoscopy and biopsy can detect current infection — the CLO test urease test allows rapid detection of H. pylori in gastric biopsy specimens — but endoscopy and biopsy are unpleasant medical procedures.Recently, noninvasive, sensitive, specific, easy to perform and patient’s well accepted methods had been developed known as urea breath test (UBT. When an infected person swallows a dose of urea labeled with an isotope of carbon — carbon-13 (13C or carbon-14 (14C – H. pylori in the gastric mucosa break down the labeled urea to form ammonia and labeled carbon dioxide. The carbon dioxide is absorbed into the bloodstream and excreted via the lungs. The patient then exhales into a device that measures the level of carbon dioxide. The urea breath test is specific for H. pylori (it detects only urease-producing bacteria, it is sensitive (the labeled urea reaches a large area of the stomach and thus reflects total gastric urease activity and the results can be

  18. Efectos adversos del tratamiento con interferón alfa-2b humano recombinante y rivabirina en pacientes con hepatitis crónica C

    OpenAIRE

    Mulet Pérez, Agustín; Pullés Labadié, Menelio; Gámez Escalona, Martha; Mulet Gámez, Agustín; Díaz Santos, Oscar; Infante Velázquez, Mirtha

    2011-01-01

    INTRODUCCIÓN: el tratamiento de la hepatitis crónica C continúa siendo un reto. La combinación que mejores resultados ha demostrado, es la de interferón con ribavirina, pero puede originar efectos adversos con dificultades para la adherencia al tratamiento que en ocasiones, incluso, obligan a suspenderlo. OBJETIVO: identificar las reacciones adversas del tratamiento de la combinación de interferón con ribavirina. MÉTODOS: se realizó un estudio de una serie de 13 pacientes con hepatitis crónic...

  19. How reliable are the sup 14 C-urea breath test and specific serology for the detection of gastric campylobacter

    Energy Technology Data Exchange (ETDEWEB)

    Husebye, E; O' Leary, D; Skar, V; Melby, K [Ullevaal Sykehus, Oslo (Norway)

    1990-01-01

    Detection of gastric campylobacter by the {sup 14}C-urea breath test and serology were correlated to biopsy culture in 25 unselected outpatients referred for gastroscopy. All the 17 culture-positive patients had positive {sup 14}C-urea breath test, and 16 had positive serology. Of eight culture-negative patients, six patients had negative breath test and seven negative serology. A high degree of reproducibility was found when two subsequent breath tests were performed in 11 healthy volunteers. The breath test values obtained at 10 min showed a strong correlation to the accumulated values within 30 min. Breath sampling once, 10 min after intake of 2.5 {mu}Ci {sup 14}C-urea, seems sufficient for the detection of gastric campylobacter. The {sup 14}C-urea breath test correlates well with biopsy culture and provides a sensitive tool for the detection of gastric campylobacter. Serology also corresponds well with biopsy culture and should provide a useful tool for epidemiologic studies. 22 refs., 4 figs., 1 tab.

  20. Effect of an ntrC mutation on amino acid or urea utilization and on nitrogenase switch-off in Herbaspirillum seropedicae.

    Science.gov (United States)

    Gusso, Claudio L; de Souza, Emanuel M; Rigo, Liu Un; de Oliveira Pedrosa, Fábio; Yates, M G; de M Rego, Fabiane G; Klassen, Giseli

    2008-03-01

    Herbaspirillum seropedicae is a nitrogen-fixing bacterium that grows well with ammonium chloride or sodium nitrate as alternative single nitrogen sources but that grows more slowly with L-alanine, L-serine, L-proline, or urea. The ntrC mutant strain DCP286A was able to utilize only ammonium or urea of these nitrogen sources. The addition of 1 mmol.L-1 ammonium chloride to the nitrogen-fixing wild-type strain inhibited nitrogenase activity rapidly and completely. Urea was a less effective inhibitor; approximately 20% of nitrogenase activity remained 40 min after the addition of 1 mmol x L-1 urea. The effect of the ntrC mutation on nitrogenase inhibition (switch-off) was studied in strain DCP286A containing the constitutively expressed gene nifA of H. seropedicae. In this strain, nitrogenase inhibition by ammonium was completely abolished, but the addition of urea produced a reduction in nitrogenase activity similar to that of the wild-type strain. The results suggest that the NtrC protein is required for assimilation of nitrate and the tested amino acids by H. seropedicae. Furthermore, NtrC is also necessary for ammonium-induced switch-off of nitrogenase but is not involved in the mechanism of nitrogenase switch-off by urea.

  1. Fe{sub 3}C/Fe nanoparticles with urea: Synthesis, structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaobai [College of Chemistry, Jilin University, Changchun, 130012 (China); School of Chemical and Pharmaceutical Engineering, Jilin Institute of Chemical Technology, Jilin, 132022 (China); Zhang, Daguang [Department of Orthopaedic Surgery, the First Hospital of Jilin University, Changchun, 130021 China (China); Ren, Xiaozhen; Gao, Jiajia [College of Chemistry, Jilin University, Changchun, 130012 (China); Han, Yu [Department of Chemistry, College of Science, Yanbian University, Yanji, 133002 China (China); Chen, Xiaodong [College of Chemistry, Jilin University, Changchun, 130012 (China); Shi, Zhan [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012 (China); Yang, Hua [College of Chemistry, Jilin University, Changchun, 130012 (China)

    2016-12-15

    Fe{sub 3}C/Fe nanocomposites were synthesized by a sol–gel method. Using urea as carbon source and reduce agent in the reaction process. The CTAB works as the surfactant and the bromine contained in CTAB plays a catalytic role. Appropriate choices of the amount of urea and CTAB, reaction temperature and time are very important to obtain high-quality of products. Above 650 °C, the precursor gel turned into the nanocomposites composed of iron carbide and iron. Their structures and magnetic properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The possible formation mechanism of as-prepared nanostructures is discussed. - Highlights: • The Fe{sub 3}C/Fe composites were synthetized by sol–gel method. • Their structure, magnetic properties are researched by XRD, VSM and TEM. • The possible formation mechanisms of the composites is discussed.

  2. A 15N study on dietary urea utility in young pigs fed with a low protein diet

    International Nuclear Information System (INIS)

    Niiyama, Masayoshi; Kagota, Katsumoto; Iwase, Toshio; Namioka, Shigeo

    1978-01-01

    To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with 15 N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed and optimal protein diet (DCP 13.3%) with 2% urea (group A). 15 N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of 15 N-urea. The 15 N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of 15 N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis. (author)

  3. Metabolism of urea in kids fed different levels of urea molasses diets

    International Nuclear Information System (INIS)

    Lal, M.; Singh, U.B.; Verma, D.N.

    1981-01-01

    Urea entry rates were measured in the body pool of Barbari kids using a single injection isotope dilution technique. The kids were divided into five groups (T 1 , T 2 , T 3 , T 4 and T 5 ) and they were fed different levels of urea molasses viz., 10, 25, 35, 40 and 0 percent to meet their DCP requirement along with concentrate mixture and oat hay as per A.R.C. recommendation. Urea entry rate was significantly higher (P 1 and the control group (T 5 without urea in their diets) than that of T 2 , T 3 and T 4 which were not significantly different from each other. (author)

  4. Urea retranslocation from senescing Arabidopsis leaves is promoted by DUR3-mediated urea retrieval from leaf apoplast

    Science.gov (United States)

    Bohner, Anne; Kojima, Soichi; Hajirezaei, Mohammad; Melzer, Michael; von Wirén, Nicolaus

    2015-01-01

    In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short-lived nitrogen (N) catabolite serving urease-mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels showed a parallel increase with senescence markers like ORE1 in a plant age- and leaf age-dependent manner. Deletion of DUR3 decreased urea accumulation in leaves, whereas the fraction of urea lost to the leaf apoplast was enhanced. Under natural and N deficiency-induced senescence DUR3 promoter activity was highest in the vasculature, but was also found in surrounding bundle sheath and mesophyll cells. An analysis of petiole exudates from wild-type leaves revealed that N from urea accounted for >13% of amino acid N. Urea export from senescent leaves further increased in ureG-2 deletion mutants lacking urease activity. In the dur3 ureG double insertion line the absence of DUR3 reduced urea export from leaf petioles. These results indicate that urea can serve as an early metabolic marker for leaf senescence, and that DUR3-mediated urea retrieval contributes to the retranslocation of N from urea during leaf senescence. PMID:25440717

  5. INSUFICIENCIA RENAL AGUDA CON UREMIA NORMAL EN PACIENTE MONO-RENO SECUNDARIA A PIELONEFRITIS AGUDA

    Directory of Open Access Journals (Sweden)

    Musso CG

    2006-03-01

    Full Text Available RESUMEN:La insuficiencia renal aguda es un sindrome que característicamente cursa con niveles plasmáticos elevados de urea y creatinina. Sin embargo, hay situaciones clínicas en las cuales este sindrome puede cursar con un incremento de la creatininemia sin presentar elevación de la uremia.En este reporte presentamos un caso clínico de una insuficiencia renal aguda con uremia normal secundaria a una pielonefritis aguda en un paciente con riñón único. El paciente presentaba una elevada excreción fraccional de urea lo cual podía explicar su uremia normal pese a estar cursando una caída del filtrado gomerular. Dicha excreción de urea elevada fue interpretada como secundaria a una diabetes insipida nefrogénica y una alteración en el recirculado intra-renal de la urea ambos producto de la pielonefritis aguda. Concluimos que la pielonefritis aguda en un paciente mono-reno puede presentarse con un patrón de insuficiencia renal aguda con uremia normal. SUMMARYAcute renal failure is a syndrome that usually runs with an increase in creatinine and urea plasma levels. However, there are clinical situations in which this syndrome may run with an increase in plasma creatinine keeping normal the urea one.In this report we present a case of acute renal failure with normal plasma urea level secondary to an acute pyelonephritis in a single kidney patient. The patient had an increased fractional excretion of urea which could explain the normal plasma urea levels found despite of his reduced glomerular filtration. This increased urea excretion state was interpreted as a consequence of the nephrogenic diabetes insipidus and alteration of the intra-renal urea reciclying process that the acute pyelonephritis induced. In conclusion: Acute pyelonephritis in a single kidney patient can appear as a pattern of acute renal failure with normal plasma urea levels.

  6. INSUFICIENCIA RENAL AGUDA CON UREMIA NORMAL EN PACIENTE MONO-RENO SECUNDARIA A PIELONEFRITIS AGUDA

    Directory of Open Access Journals (Sweden)

    Musso CG

    2007-04-01

    Full Text Available RESUMENLa insuficiencia renal aguda es un sindrome que característicamente cursa con niveles plasmáticos elevados de urea y creatinina. Sin embargo, hay situaciones clínicas en las cuales este sindrome puede cursar con un incremento de la creatininemia sin presentar elevación de la uremia. En este reporte presentamos un caso clínico de una insuficiencia renal aguda con uremia normal secundaria a una pielonefritis aguda en un paciente con riñón único. El paciente presentaba una elevada excreción fraccional de urea lo cual podía explicar su uremia normal pese a estar cursando una caída del filtrado gomerular. Dicha excreción de urea elevada fue interpretada como secundaria a una diabetes insipida nefrogénica y una alteración en el recirculado intra-renal de la urea ambos producto de la pielonefritis aguda. Concluimos que la pielonefritis aguda en un paciente mono-reno puede presentarse con un patrón de insuficiencia renal aguda con uremia normal.SUMMARYAcute renal failure is a syndrome that usually runs with an increase in creatinine and urea plasma levels. However, there are clinical situations in which this syndrome may run with an increase in plasma creatinine keeping normal the urea one. In this report we present a case of acute renal failure with normal plasma urea level secondary to an acute pyelonephritis in a single kidney patient. The patient had an increased fractional excretion of urea which could explain the normal plasma urea levels found despite of his reduced glomerular filtration. This increased urea excretion state was interpreted as a consequence of the nephrogenic diabetes insipidus and alteration of the intra-renal urea reciclying process that the acute pyelonephritis induced. In conclusion: Acute pyelonephritis in a single kidney patient can appear as a pattern of acute renal failure with normal plasma urea levels.

  7. Measurement of synovial fluid volume using urea.

    Science.gov (United States)

    Kraus, V B; Stabler, T V; Kong, S Y; Varju, G; McDaniel, G

    2007-10-01

    To examine the utility of using urea concentrations for determining Synovial Fluid (SF) joint volume in effused and non-effused joints. Knee joint SF was aspirated from 159 human study participants with symptomatic osteoarthritis of at least one knee either directly (165 knees) or by lavage (110 knees). Serum was obtained immediately prior to SF aspiration. Participants were asked to rate individual knee pain, aching or stiffness. SF and serum urea levels were determined using a specific enzymatic method run on an automated CMA600 analyzer. Cell counts were performed on direct SF aspirates when volume permitted. The formula for calculating SF joint volume was as follows: V(j)=C(D)(V(I))/(C-C(D)) with V(j)=volume of SF in entire joint, C(D)=concentration of urea in diluted (lavage) SF, V(I)=volume of saline injected into joint, and C=concentration of urea in undiluted (neat) SF derived below where C=0.897(C(S)) and C(s)=concentration of urea in serum. There was an excellent correlation (r(2)=0.8588) between SF and serum urea in the direct aspirates with a ratio of 0.897 (SF/serum). Neither urea levels nor the SF/serum ratio showed any correlation with Kellgren Lawrence (KL) grade, or cell count. While urea levels increased with age there was no change in the ratio. Intraarticular SF volumes calculated for the lavaged knees ranged from 0.555 to 71.71ml with a median volume of 3.048ml. There was no correlation of SF volume to KL grade but there was a positive correlation (P=0.001) between SF volume and self-reported individual knee pain. Our urea results for direct aspirates indicate an equilibrium state between serum and SF with regard to the water fraction. This equilibrium exists regardless of disease status (KL grade), inflammation (cell count), or age, making it possible to calculate intraarticular volume of lavaged joints based upon this urea method. Most of the joint volumes we calculated fell within the previously reported range for normal knees of 0.5-4.0ml

  8. Effect of nitrogen supplementation on urea kinetics and microbial use of recycled urea in steers consuming corn-based diets.

    Science.gov (United States)

    Brake, D W; Titgemeyer, E C; Jones, M L; Anderson, D E

    2010-08-01

    We studied the effects of supplementing N as distillers dried grains with solubles (DDGS) or urea to steers consuming corn-based diets. Six ruminally and duodenally cannulated steers (244 kg) were used in 2 concurrent 3 x 3 Latin squares and fed 1 of 3 corn-based diets: control (10.2% CP), urea (13.3% CP), or DDGS (14.9% CP). Periods were 14 d, with 9 d for adaptation and 5 d for collection of urine and feces. Urinary (15)N(15)N-urea enrichments, resulting from venous infusions of (15)N(15)N-urea, were used to measure urea kinetics. Dry matter intake (6.0 kg/d) was not affected by treatment, but N intake differed (99, 151, and 123 g/d for the control, DDGS, and urea treatments, respectively). Urea-N synthesis tended to be greater (P = 0.09) for DDGS (118 g/d) than for the control treatment (52 g/d), with the urea treatment (86 g/d) being intermediate. Urea-N excreted in the urine was greater (P urea treatments (29 g/d) than for the control treatment (13 g/d). Gastrointestinal entry of urea-N was not statistically different among treatments (P = 0.25), but was numerically greatest for DDGS (83 g/d), intermediate for urea (57 g/d), and least for the control (39 g/d). The amount of urea-N returned to the ornithine cycle tended to be greater (P = 0.09) for the DDGS treatment (47 g/d) than for the urea (27 g/d) or control treatment (16 g/d). The fraction of recycled urea-N that was apparently used for anabolism tended (P = 0.14) to be greater for the control treatment (0.56) than for the DDGS treatment (0.31), with the urea treatment (0.45) being intermediate, but no differences were observed among treatments in the amount of urea-N used for anabolism (P = 0.66). Urea kinetics in cattle fed grain-based diets were largely related to the amount of N consumed. The percentage of urea production that was captured by ruminal bacteria was greater (P urea treatment (22%), but the percentage of duodenal microbial N flow that was derived from recycled urea-N tended (P = 0.10) to

  9. urea space versus tritiated water space as an in vivo predtctor

    African Journals Online (AJOL)

    Kock (1973) consider urea space in the ruminant to be a measure of empty body water (total body water less the water in the digestive tract) rather than total body water. The study reported in this paper evaluates the pros and cons of urea space measurement as compared to tritiated water space measurement in terms of ...

  10. Pseudomonas aeruginosa cytochrome c551 denaturation by five systematic urea derivatives that differ in the alkyl chain length.

    Science.gov (United States)

    Kobayashi, Shinya; Fujii, Sotaro; Koga, Aya; Wakai, Satoshi; Matubayasi, Nobuyuki; Sambongi, Yoshihiro

    2017-07-01

    Reversible denaturation of Pseudomonas aeruginosa cytochrome c 551 (PAc 551 ) could be followed using five systematic urea derivatives that differ in the alkyl chain length, i.e. urea, N-methylurea (MU), N-ethylurea (EU), N-propylurea (PU), and N-butylurea (BU). The BU concentration was the lowest required for the PAc 551 denaturation, those of PU, EU, MU, and urea being gradually higher. Furthermore, the accessible surface area difference upon PAc 551 denaturation caused by BU was found to be the highest, those by PU, EU, MU, and urea being gradually lower. These findings indicate that urea derivatives with longer alkyl chains are stronger denaturants. In this study, as many as five systematic urea derivatives could be applied for the reversible denaturation of a single protein, PAc 551 , for the first time, and the effects of the alkyl chain length on protein denaturation were systematically verified by means of thermodynamic parameters.

  11. Efectividad de la pomada de urea en las verrugas plantares Effectiveness of the urea ointment in the feet warts

    Directory of Open Access Journals (Sweden)

    Elisa Chacón Eduardo

    2009-10-01

    Full Text Available Se hizo un ensayo clinicoterapéutico en 60 pacientes atendidos en la consulta de Dermatología del Hospital Provincial Docente “Dr. Joaquín Castillo Duany” de Santiago de Cuba, durante el 2008, con el fin evaluar la efectividad de la pomada de urea en las verrugas plantares. Se conformaron 2 grupos (de estudio y control: los primeros recibieron pomada de urea al 20 % y los segundos pomada salicílica al 40 %. La pomada de urea resultó más eficaz para eliminar las manifestaciones clínicas de esa lesión, en un período de 6 a 8 semanas y no hubo reacciones adversas.A clinical therapeutical trial was made in 60 patients assisted at the Dermatology department of "Dr. Joaquín Castillo Duany" Teaching Provincial Hospital from Santiago de Cuba, during 2008, aimed at evaluating the effectiveness of the urea ointment in the feet warts. They conformed to 2 groups (study and control: the first group received urea ointment at 20% and the second one salicylic ointment at 40%. The urea ointment was more effective to eliminate the clinical manifestations of that lesion, in a period of 6 to 8 weeks and there were not adverse reactions.

  12. /sup 15/N study on dietary urea utility in young pigs fed with a low protein diet

    Energy Technology Data Exchange (ETDEWEB)

    Niiyama, M; Kagota, K; Iwase, T; Namioka, S [Hokkaido Univ., Sapporo (Japan)

    1978-10-01

    To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with /sup 15/N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed and optimal protein diet (DCP 13.3%) with 2% urea (group A). /sup 15/N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of /sup 15/N-urea. The /sup 15/N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of /sup 15/N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis.

  13. Isotopic studies of urea metabolism in rabbits

    Science.gov (United States)

    Regoeczi, E.; Irons, L.; Koj, A.; McFarlane, A. S.

    1965-01-01

    1. The half-life of [15N]urea was found to be significantly longer than that of [14C]urea injected at the same time, the differences being due to endogenous catabolism of urea, which is accompanied by little or no reutilization of 14C but is approx. 20% for 15N. [15N]Urea therefore appears to be valueless as an indicator of nitrogen metabolism unless the extents of endogenous catabolism of urea and of fractional reutilization of 15N can be separately estimated. 2. Though measurements of the radioactivity of expired 14CO2 confirmed the existence of considerable urea catabolism these could not be used for quantitative assessments. 3. Alternative graphical methods based on [14C]urea specific activities in plasma and urine samples were used to calculate the fraction of urea production that is excreted. Values by the two methods were in good agreement and showed that some animals excrete less than half the urea that they produce. 4. Specific activity differences between simultaneous samples of urinary and plasma urea reflect the presence of a pool of urea in the kidney that is not in equilibrium with the body urea pool. Calculations indicate the presence of urea in the kidney that in some cases may represent as much as 15% of the body pool, and in two animals in which post-mortem renal analyses were performed the masses of urea found agreed closely with the calculated values. 5. A model for urea metabolism is proposed that includes this pool in the excretory pathway. The related theory is shown to be adequate to explain the shape of the specific activity curves of urinary urea from the time of injection and the constant delay of the specific activity of urinary urea, relative to that of plasma urea, that is observed after a short preliminary equilibration period. 6. The body urea pool was calculated from the activity retained at 1·5hr. by excluding renal activity and the corrected specific activity of plasma urea at the same time. The urea pool was calculated to be

  14. Vísceras, humores, alientos. Alma premoderna y subjetividad moderna

    OpenAIRE

    Rejón Altable, Carlos

    2016-01-01

    La medicina premoderna se ocupó tempranamente de la locura. Sin embargo, no supo proporcionar un concepto sólido de enfermedad mental a la psiquiatría naciente, que permaneció atrapada en las contradicciones de la forma sujeto moderna con la que nace. Este texto reconstruye algunos conceptos básicos de la medicina premoderna para mostrar cómo dan expresión metafórica a ciertas características de la estructura ontológica humana necesarias para comprender la enfermedad mental: escisión, individ...

  15. Quantitative aspect of the endogenous urea cycle in goats

    International Nuclear Information System (INIS)

    Ide, Yu

    1975-01-01

    The turnover of plasma urea was studied in goats fed rations with different protein contents by using 14 C- and 15 N-urea as tracers. The biological half-life time of urea determined with 15 N-urea was always longer than that determined with 14 C-urea, reflecting the difference in the metabolic pathway between the urea hydrolysates, ammonia and carbon dioxide. It was roughly estimated from the turnover studies that more than a half the quantity of urea synthesized might be transferred to the alimentary canal, including the rumen, where it underwent dissociation, with a decrease in the protein content of the ration, the percentage of transfer and dissociation increased. The 14 C-urea discharged into the urine was less than 57% of the administered dose. It decreased to 3.9% in goats fed rations with a low protein content. The rate of urea turnover determined with 15 N-urea was nearly consistent with the rate of urea discharge into the urine in goats fed higher protein rations. In goats fed lower protein rations, on the other hand, the rate of urea discharge decreased and its consistency with the rate of turnover determined with 15 N-urea was upset. This was caused by assimilation of urea-nitrogen in rumen microorganisms, as was convinced by studying the incorporation of urea- 15 N into the fraction of rumen microorganisms. It was assumed that in goats fed lower protein rations the bulk of urea synthesized might have entered the endogenous recycling system within the body and assimilated by rumen microorganisms. (auth.)

  16. Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.

    Science.gov (United States)

    Anderson, W Gary; Good, Jonathan P; Pillans, Richard D; Hazon, Neil; Franklin, Craig E

    2005-10-01

    Plasma urea levels and hepatic urea production in the euryhaline bull shark, Carcharhinus leucas, acclimated to freshwater and seawater environments were measured. It was found that plasma urea concentration increased with salinity and that this increase was, in part, the result of a significant increase in hepatic production of urea. This study provides direct evidence that hepatic production of urea plays an important role in the osmoregulatory strategy of C. leucas. (c) 2005 Wiley-Liss, Inc.

  17. Prevalence of Helicobacter Pylori in gastric cancer in a south-east Asian population by 14C-urea breath test

    International Nuclear Information System (INIS)

    Chung, A.Y-F; Chow, P.K.H.; Yu, W-K.; Ho, J.M.S.; Chan, H-S.; Wong, W-K.; Soo, K-C.

    2001-01-01

    Helicobacter pylori is believed to play an important role in the aetiology of gastric cancer. There is a great variability in seropositivity and histological frequency of H. pylori in gastric cancer. The present prospective study investigates the prevalence of H. pylori infection in gastric cancer patients using 14C-urea breath testing. Patients with endoscopic biopsy-proven gastric cancer were fasted for 6 h prior to ingesting 18.5 x 104 Bq of 14C-urea cocktail orally. Breath samples were collected after 20 min by AS/King them to blow into a hyamine solution and measurements were read in a scintillation counter. Fifty out of 51 patients (98%) with gastric cancer were positive on the 14C-urea breath test compared to 29 patients (61%) who were positive on histology. There was no association between sex, age or tumour site, stage, differentiation, Lauren type and H. pylori status. The test was negative in one patient with cardiac tumour in which histology of the resected specimen was also negative for the bacteria. Active H. pylori infection is highly prevalent in gastric cancer in a South-East Asian population. The 14C-urea breath test is a highly sensitive method for detecting the presence of H. pylori even in gastric adenocarcinoma irrespective of the stage

  18. A methodological aspect of the 14C-urea breath test used in Helicobacter pylori diagnosis

    International Nuclear Information System (INIS)

    Kopanski, Z.; Niziol, J.; Micherdzinski, J.; Wasilewska-Radwanska, M.; Cienciala, A.; Lasa, J.; Witkowska, B.

    1996-01-01

    The main purpose of those investigations was optimisation of the performing time of the breath test with 14 C-labelled urea which reveals Helicobacter pylori infection. It was analysed 117 species, preselected according to endoscopy and histopathology results, 56 of them have suffered from chronic gastritis and 61 from gastric ulcer disease. Using microbiology diagnosis (culture + IFP test) it was found that 86 species were H. pylori infected. This group of patients were next subject to investigations with the breath test with 14 C-labelled urea. Measurements of radioactivity of breathe air have been carried out for 30 minutes. The obtained results allow us to maintain that the optimal time of duration of the test described above is 30 minutes. (author)

  19. Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

    OpenAIRE

    Monari, S.; Ranieri, A.; Di Rocco, G.; van der Zwan, G.; Peressini, S.; Tavagnacco, C.; Millo, D.; Borsari, M.

    2009-01-01

    The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The muc...

  20. Confirmation of eradication of Helicobacter pylori infection by 14C-urea breath test

    International Nuclear Information System (INIS)

    Pathak, C.M.; Bhasin, D.K.; Sharma, B.C.; Roy, P.; Vaiphei, K.

    1998-01-01

    Helicobacter pylori (H. pylori) is a potent urease producer, a characteristic that has been exploited in the development of the 14 C-urea breath test (UBT). 14 C-UBT is being used as a highly reliable test for the diagnosis of H. pylori infection. There is paucity of reports on the utility of this test to confirm the H. pylori eradication after its treatment. The study was conducted to determine the utility of 14 C-UBT in confirming the eradication of H. pylori

  1. Total synthesis of [2-11C]thymidine from [11C]urea: A tracer of choice for measurement of cellular proliferation using PET

    International Nuclear Information System (INIS)

    Labar, D.; Vander Borght, T.

    1990-01-01

    In preliminary studies of cellular proliferation with [methyl- 11 C]thymidine, the labelled degradative products mask the progressive incorporation of the tracer into DNA. The authors have developed a procedure for the synthesis of [2- 11 C]thymidine to circumvent this difficulty, using a [ 11 C]urea precursor

  2. Application of 13C-labeling and 13C-13C COSY NMR experiments in the structure determination of a microbial natural product.

    Science.gov (United States)

    Kwon, Yun; Park, Sunghyouk; Shin, Jongheon; Oh, Dong-Chan

    2014-08-01

    The elucidation of the structures of complex natural products bearing many quaternary carbons remains challenging, even in this advanced spectroscopic era. (13)C-(13)C COSY NMR spectroscopy shows direct couplings between (13)C and (13)C, which comprise the backbone of a natural product. Thus, this type of experiment is particularly useful for natural products bearing consecutive quaternary carbons. However, the low sensitivity of (13)C-based NMR experiments, due to the low natural abundance of the (13)C nucleus, is problematic when applying these techniques. Our efforts in the (13)C labeling of a microbial natural product, cyclopiazonic acid (1), by feeding (13)C-labeled glucose to the fungal culture, enabled us to acquire (13)C-(13)C COSY NMR spectra on a milligram scale that clearly show the carbon backbone of the compound. This is the first application of (13)C-(13)C COSY NMR experiments for a natural product. The results suggest that (13)C-(13)C COSY NMR spectroscopy can be routinely used for the structure determination of microbial natural products by (13)C-enrichment of a compound with (13)C-glucose.

  3. 1,3-disubstituted ureas functionalized with ether groups are potent inhibitors of the soluble epoxide hydrolase with improved pharmacokinetic properties.

    Science.gov (United States)

    Kim, In-Hae; Tsai, Hsing-Ju; Nishi, Kosuke; Kasagami, Takeo; Morisseau, Christophe; Hammock, Bruce D

    2007-10-18

    Soluble epoxide hydrolase (sEH) is a therapeutic target for treating hypertension and inflammation. 1,3-Disubstituted ureas functionalized with an ether group are potent sEH inhibitors. However, their relatively low metabolic stability leads to poor pharmacokinetic properties. To improve their bioavailability, we investigated the effect of incorporating various polar groups on the ether function on the inhibition potencies, physical properties, in vitro metabolic stability, and pharmacokinetic properties. The structure-activity relationship studies showed that a hydrophobic linker between the urea group and the ether function is necessary to keep their potency. In addition, urea-ether inhibitors having a polar group such as diethylene glycol or morpholine significantly improved their physical properties and metabolic stability without any loss of inhibitory potency. Furthermore, improved pharmacokinetic properties in murine and canine models were obtained with the resulting inhibitors. These findings will facilitate the usage of sEH inhibitors in animal models of hypertension and inflammation.

  4. Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation.

    Science.gov (United States)

    Kaur, Gurmeet; Balamurugan, P; Uma Maheswari, C; Anitha, A; Princy, S Adline

    2016-01-01

    Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25-62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

  5. Synthesis of [5,6-13C2, 1-14C]olivetolic acid, methyl [1'-13C]olivetolate and [5,6-13C2, 1-14C]cannabigerolic acid

    International Nuclear Information System (INIS)

    Porwoll, J.P.; Leete, E.

    1985-01-01

    Potential advanced intermediates in the biosynthesis of delta 9 -tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous 13 C atoms and 14 C. Methyl [5,6- 13 C 2 , 1- 14 C]olivetolate was prepared from lithium [ 13 C 2 ]acetylide and dimethyl [2- 14 C]malonate. Reaction with geranyl bromide afforded methyl [5,6- 13 C 2 , 1- 14 C]cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The 13 C- 13 C couplings observable in the 13 C NMR spectra of these 13 C-enriched compounds and their synthetic precursors are recorded. Methyl [1'- 14 C]olivetolate was prepared from 13 CO 2 to confirm assignments of the 13 C chemical shifts in the pentyl side chain of these compounds. (author)

  6. Urea metabolism in cattle and buffaloes fed diets containing NPN salts, usin g urea radiotracers

    International Nuclear Information System (INIS)

    Dhiman, T.R.; Arora, S.P.

    1990-01-01

    Urea metabolism studies were conducted using isotope dilution techniques. Animals in groups 1 and 3 were fed basal diet (S, 0.11%) supplemented with urea (test diet 1) and those of groups 2 and 4 supplemented urea plus ammonium sulphate (test diet 2) containing 0.22% S. A single injection of a mixture of 15 N-urea and 14 C-urea was given intravenously and 51 Cr-EDTA was given as a single infusion intraruminally. The pattern of release of ammonia, mean ruminal ammonia, plasma urea, rumen fluid outflow rate, rumen ammonia pool size and ammonia outflow from rumen remained unaffected due to different dietary treatments. On an average, 73.3% of plasma urea synthesized was excreted in urine with test diet 1 and showing 26.6% degradation in the gastrointestinal tract, whereas 68.8% was excreted with test diet 2 and showing 31.3% degradation in the gastrointestinal tract. At 24 hr, 18.33 to 20.93% of nitrogen entering the ruminal ammonia pool was derived from plasma urea in calves of groups 1 and 2 and 24.22 to 27.49 in buffalo calves of groups 3 and 4 respectively. Sulphur supplementation through ammonium sulphate (N : S, 10 :1) resulted in better utilization of nitrogen with test diet 2 by lowering urea excretion rate and increasing urea recycling rate in both the species. (author). 5 tabs., 16 refs

  7. Transfer of blood urea into the goat colon

    International Nuclear Information System (INIS)

    Engelhardt, W. von; Hinderer, S.

    1976-01-01

    Transfer of blood urea to the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously, total urea turnover was estimated using 14 C-labelled urea. Three animals in the weight range 50-70 k were used, with appropriately placed cannulae. The entry of blood urea into the total gastrointestinal tract was estimated from the difference between total urea turnover renal urea excretion. When experimental conditions remained constant, such as the permeability of the gastrointestinal tract wall, blood urea diffusion into the colon depended on plasma urea concentration. Results of varying feeding conditions demonstrated that changes in permeability of the gastrointestinal tract will have a more pronounced influence on the amounts of blood urea entering the gastrointestinal tract than differences in plasma urea concentration

  8. The effect of urea and urea-modified halloysite on performance of PCL

    Czech Academy of Sciences Publication Activity Database

    Khunová, V.; Kelnar, Ivan; Kristóf, J.; Dybal, Jiří; Kratochvíl, Jaroslav; Kaprálková, Ludmila

    2015-01-01

    Roč. 120, č. 2 (2015), s. 1283-1291 ISSN 1388-6150 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:61389013 Keywords : PCL * urea * halloysite Subject RIV: JI - Composite Materials Impact factor: 1.781, year: 2015

  9. Deposits from Creams Containing 20% (w/w) Urea and Suppression of Crystallization (Part 2): Novel Analytical Methods of Urea Accumulated in the Stratum Corneum by Tape stripping and Colorimetry.

    Science.gov (United States)

    Goto, Norio; Morita, Yutaka; Terada, Katsuhide

    2016-01-01

    The transfer of urea from a urea formulation to the stratum corneum varies with the formulation base and form, and impacts the formulation's therapeutic effect. Consequently, determining the amount of urea transferred is essential for developing efficient formulations. This study assessed a simple method for measuring the amount of urea accumulated in the stratum corneum. Conventional methods rely on labeling urea used in the formulation with radiocarbon ((14)C) or other radioactive isotopes (RIs), retrieving the transferred urea from the stratum corneum by tape stripping, then quantitating the urea. The handling and use of RIs, however, is subject to legal regulation and can only be performed in sanctioned facilities, so methods employing RIs are neither simple nor convenient. We therefore developed a non-radiolabel method "tape stripping-colorimetry (T-C)" that combines tape stripping with colorimetry (urease-glutamate dehydrogenase (GLDH)) for the quantitative measurement of urea. Urea in the stratum corneum is collected by tape stripping and measured using urease-GLDH, which is commonly used to measure urea nitrogen in blood tests. The results indicate that accurate urea measurement by the T-C method requires the application of 1400 mg (on hairless rats) of a 20% urea solution on a 50 cm(2) (5×10 cm) area. Further, we determined the amount of urea accumulated in the stratum corneum using formulations with different urea concentrations, and the time course of urea accumulation from formulations differing in the rate of urea crystallization. We demonstrate that the T-C method is simple and convenient, with no need for (14)C or other RIs.

  10. The Effect of Annealing Temperature on Nickel on Reduced Graphene Oxide Catalysts on Urea Electrooxidation

    International Nuclear Information System (INIS)

    Glass, Dean E.; Galvan, Vicente; Prakash, G.K. Surya

    2017-01-01

    Highlights: •Nickel was reduced on graphene oxide and annealed under argon from 300 to 700 °C. •Nickel was oxidized from the removal of oxygen groups on the graphene oxide. •Higher annealed catalysts displayed decreased urea electrooxidation currents. •Micro direct urea/hydrogen peroxide fuel cells were employed for the first time. •Ni/rGO catalysts displayed enhanced fuel cell performance than the bare nickel. -- Abstract: The annealing temperature effects on nickel on reduced graphene oxide (Ni/rGO) catalysts for urea electrooxidation were investigated. Nickel chloride was directly reduced in an aqueous solution of graphene oxide (GO) followed by annealing under argon at 300, 400, 500, 600, and 700 °C, respectively. X-ray Diffraction (XRD) patterns revealed an increase in the crystallite size of the nickel nanoparticles while the Raman spectra displayed an increase in the graphitic disorder of the reduced graphene oxide at higher annealing temperatures due to the removal of oxygen functional groups. The Ni/rGO catalysts annealed at higher temperatures displayed oxidized nickel surface characteristics from the Ni 2p X-ray Photoelectron Spectra (XPS) due to the oxidation of the nickel from the oxygen functional groups in the graphitic lattice. In the half-cell testing, the onset potential of urea electrooxidation decreased while the urea electrooxidation currents decreased as the annealing temperature was increased. The nickel catalyst annealed at 700 °C displayed a 31% decrease in peak power density while the catalyst annealed at 300 °C displayed a 13% increase compared with the unannealed Ni/rGO catalyst in the micro direct urea/hydrogen peroxide fuel cells tests.

  11. MIN 14C UBT: A combination of gastric basal transit and 14C-urea breath test for the detection of helicobacter pylori infection in human beings

    International Nuclear Information System (INIS)

    Zubillaga, M.; Oliveri, P.; Calcagno, M.L.; Goldman, C.; Caro, R.; Mitta, A.; Degrossi, O.; Boccio, J.

    1997-01-01

    The purpose of this work is to demonstrate that the 14 C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14 C UBT, is a modification of the conventional 14 C UBT in which low volumes of a solution of 14 C-urea together with 99m Tc-sulfur colloid are administered. The 99m Tc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the 'visualization' of the transit of the 14 C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14 CO 2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection

  12. First-time urea breath tests performed at home by 36,629 patients

    DEFF Research Database (Denmark)

    Dahlerup, Søren; Andersen, Rikke Charlotte; Nielsen, Birgitte Sperling Wilms

    2011-01-01

    BACKGROUND: The aim of the current study was (1) to describe the use of a (13) C-urea breath test (UBT) that was performed by patients at their homes as a part of a test-and-treat strategy in primary care and (2) to investigate the prevalence of Helicobacter pylori in patients taking a first...

  13. Combinatorial effects of aromatic 1,3 – disubstituted ureas and fluoride on in vitro inhibition of Streptococcus mutans biofilm formation

    Directory of Open Access Journals (Sweden)

    Gurmeet eKaur

    2016-06-01

    Full Text Available Dental caries occurs as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque. S. mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of Streptococcus mutans due to over usage of various antibiotics is a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our previous in silico findings, 1,3- disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3- disubstituted urea derivatives showed good biofilm inhibition. In addition, the synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25 ppm to 62.5 ppm in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were confirmed by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

  14. Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation.

    Science.gov (United States)

    Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

    2017-12-20

    Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food fermentation processes. Saccharomyces cerevisiae was dominant in gene transcription for urea biosynthesis and degradation. Lysinibacillus sphaericus was dominant for urea degradation. S. cerevisiae degraded 18% and L. sphaericus degraded 13% of urea in their corresponding single cultures, whereas they degraded 56% of urea in coculture after 12 h. Compared to single cultures, transcription of CAR1, DAL2, and argA, which are related to urea biosynthesis, decreased by 51, 36, and 69% in coculture, respectively. Transcription of DUR1 and ureA, which are related to urea degradation, increased by 227 and 70%, respectively. Thus, coexistence of the two strains promoted degradation of urea via transcriptional regulation of genes related to urea metabolism.

  15. The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

    NARCIS (Netherlands)

    Monari, S.; Millo, D.; Ranieri, A.; di Rocco, G.; van der Zwan, G.; Gooijer, C.; Peressini, S.; Tavagnacco, C.; Hildebrandt, P.; Borsari, M.

    2010-01-01

    We have studied the effect of urea-induced unfolding on the electron transfer process of yeast iso-1-cytochrome c and its mutant K72AK73AK79A adsorbed on electrodes coated by mixed 11-mercapto-1-undecanoic acid/11-mercapto-1-undecanol self-assembled monolayers. Electrochemical measurements,

  16. 1H, 15N and 13C assignments of domain 5 of Dictyostelium discoideum gelation factor (ABP-120) in its native and 8M urea-denatured states.

    Science.gov (United States)

    Hsu, Shang-Te Danny; Cabrita, Lisa D; Christodoulou, John; Dobson, Christopher M

    2009-06-01

    The gelation factor from Dictyostelium discoideum (ABP-120) is an actin binding protein consisting of six immunoglobulin (Ig) domains in the C-terminal rod domain. We have recently used the pair of domains 5 and 6 of ABP-120 as a model system for studying multi-domain nascent chain folding on the ribosome. Here we present the NMR assignments of domain 5 in its native and 8M urea-denatured states.

  17. 1,3-Dicyclohexyl-3-[(pyridin-2-ylcarbonyl]urea monohydrate from synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Solange M. S. V. Wardell

    2011-10-01

    Full Text Available The title urea derivative crystallizes as a monohydrate, C19H27N3O2·H2O. The central C3N grouping is almost planar (r.m.s. deviation = 0.0092 Å, and the amide and pyridine groups are substantially twisted out this plane [dihedral angles = 62.80 (12 and 34.98 (10°, respectively]. Supramolecular double chains propagating along the b-axis direction feature in the crystal packing whereby linear chains sustained by N—H...O hydrogen bonds formed between the amide groups are linked by helical chains of water molecules (linked by O—H...O hydrogen bonds. The H atom that participates in these water chains is disordered over two positions of equal occupancy. The double chains are connected into a two-dimensional array by C—H...O contacts and the layers stack along the a axis.

  18. Trazando la materia oscura con cúmulos globulares

    Science.gov (United States)

    Forte, J. C.

    Se describe la estrategia adoptada para mapear la distribución de materia oscura y bariónica en galaxias elípticas cuyos cúmulos globulares están siendo observados con los telescopios VLT y Gemini. Se ejemplifican los resultados con los datos obtenidos en el cúmulo de Fornax.

  19. Agricultural management legacy affects microbial energetics, resource utilization and active bacterial community membership during 13C-glucose consumption

    Science.gov (United States)

    Helgason, B. L.; Levy-Booth, D.; Arcand, M. M.

    2017-12-01

    Over the long-term, differences in soil management can result in fundamental changes in biogeochemical cycling. The Alternative Cropping Systems (ACS) Study at Scott, SK, Canada (est. 1994) compares organic (ORG) vs. conventionally (CON) managed crop rotations in a loamy Typic Borall. Nitrogen (N) and phosphorus (P) deficiency in the ORG systems have limited crop growth and thus plant carbon (C) inputs for over two decades, ultimately resulting in a C deficiency which has further altered biogeochemical cycling. We conducted a short-term microcosm experiment using 13C-glucose stable isotope probing (SIP) of DNA to test whether ORG soils have greater microbial C use efficiency due to long term resource limitation. Glucose-utilizing populations were dominated by Proteobacteria and Actinobacteria, with differing species-level identities and physiological capacities between CON and ORG systems. Of the 13C-utilizing taxa, relative abundance of Proteobacteria was greater in CON while Actinobacteria (and notably Firmicutes) were more dominant in ORG soils. Using isothermal calorimetry, we measured a thermodynamic efficiency (ηeff) of 0.68, which was not significantly different between soils indicating that the metabolic cost of glucose utilization was similar in CON and ORG soils. In spite of this, differential abundance analysis of 13C-labelled OTUs revealed that ORG soils had distinct active bacterial populations that were positively correlated with ηeff, ηsoil (glucose energy retained in soil) and primed soil organic matter (pSOM). In contrast, differentially abundant OTUs in the CON soils were negatively correlated with measures of thermodynamic efficiency but positively correlated with glucose-derived heat and CO2 production as well as NO3- and PO4- availability. ORG bacterial communities may co-metabolize other resources (N and P) from SOM to meet their metabolic requirements during glucose utilization, while the active bacteria in the CON soils could access these

  20. Synthesis and biological evaluation of novel urea and thiourea derivatives of valacyclovir

    Directory of Open Access Journals (Sweden)

    Katla Ramana Venkata

    2014-01-01

    Full Text Available A series of novel urea and thiourea derivatives of valacyclovir were efficiently synthesized in high yields and evaluated their antiviral activity. 2-((6-Amino-4-oxo-4,5-dihydro-1H-imidazo[4,5-c]pyridin-1-ylmethoxyethyl-2-amino-3-ethylbutanoate (valacyclovir 1 is reacted with various aromatic isocyanates/thiocyanates 2 in the presence of N, N- dimethyl piperazine as a base in THF: pyridine (4:1 to obtain valacyclovir urea/thiourea derivatives 3(a-j. The structures of the title compounds 3(a-j were confirmed by IR, NMR (1H, 13C, mass spectral and elemental analysis. The newly synthesized compounds were screened for their antiviral activity against Tobacco mosaic virus (TMV and antioxidant activity was evaluated by DPPH, SOD and GST methods. The title compounds exhibited potent antiviral and good antioxidant activities.

  1. Isotope-labelled urea to test colon drug delivery devices in vivo : principles, calculations and interpretations

    NARCIS (Netherlands)

    Maurer, Marina; Schellekens, Reinout C. A.; Wutzke, Klaus D.; Stellaard, Frans

    2013-01-01

    This paper describes various methodological aspects that were encountered during the development of a system to monitor the in vivo behaviour of a newly developed colon delivery device that enables oral drug treatment of inflammatory bowel diseases. [C-13]urea was chosen as the marker substance.

  2. Study, with the help of nuclear indicators (HTO, Urea 14C and 24Na), of the renewal of water, urea and sodium in different parts of the rat kidney in aqueous diuresis and of the gerbil kidney in osmotic diuresis or in oliguria

    International Nuclear Information System (INIS)

    Lechene, C.P.

    1965-06-01

    In the kidney of the gerbil in oliguria there exists a cortico-papillary gradient in the concentration of the sodium and of the urea; this gradient disappears in the gerbil kidney in osmotic diuresis or in the rat kidney in aqueous diuresis; in these three states of diuresis there is no significant difference in the potassium concentration between the surface and interior regions of the kidneys. Kinetic studies using tritiated water, urea 14 C and 24 Na show that water and urea in the interior regions of the kidney are only renewed very slowly (1 h) whereas the sodium is rapidly changed (1 mn). These results can be explained using WIRZ's theory concerning the mechanism of the counter-current concentration of urine. Furthermore, the evolution of the specific radioactivity of urea 14 C is favorable for a cortical synthesis of urea. (author) [fr

  3. Synthesis of [13C6]-labelled phenethylamine derivatives for drug quantification in biological samples.

    Science.gov (United States)

    Karlsen, Morten; Liu, HuiLing; Berg, Thomas; Johansen, Jon Eigill; Hoff, Bård Helge

    2014-05-15

    The availability of high-quality (13)C-labelled internal standards will improve accurate quantification of narcotics and drugs in biological samples. Thus, the synthesis of 10 [(13)C6]-labelled phenethylamine derivatives, namely amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, 4-methoxyamphetamine, 4-methoxymethamphetamine, 3,5-dimethoxyphenethylamine 4-bromo-2,5-dimethoxyphenethylamine and 2,5-dimethoxy-4-iodophenethylamine, have been undertaken. [(13)C6]-Phenol proved to be an excellent starting material for making (13)C-labelled narcotic substances in the phenethylamine class, and a developed Stille-type coupling enabled an efficient synthesis of the 3,4-methylenedioxy and 4-methoxy derivatives. The pros and cons of alternative routes and transformations are also discussed. The [(13)C6]-labelled compounds are intended for use as internal standards in forensic analysis, health sciences and metabolomics studies by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Prevalence and risk factors of helicobacter pylori in Turkey: a nationally-representative, cross-sectional, screening with the 13C-Urea breath test

    Science.gov (United States)

    2013-01-01

    Background Helicobacter pylori is an important global pathogen infecting approximately 50% of the world’s population. This study was undertaken in order to estimate the prevalence rate of Helicobacter pylori infections among adults living in Turkey and to investigate the associated risk factors. Method This study was a nationally representative cross sectional survey, using weighted multistage stratified cluster sampling. All individuals aged ≥18 years in the selected households were invited to participate in the survey. Ninety two percent (n = 2382) of the households in 55 cities participated; 4622 individuals from these households were tested with the 13C-Urea breath test. Helicobacter pylori prevalence and associated factors were analysed by the t test, chi square and multiple logistic regression with SPSS11.0. Results The weighted overall prevalence was 82.5% (95% CI: 81.0-84.2) and was higher in men. It was lowest in the South which has the major fruit growing areas of the country. The factors included in the final model were sex, age, education, marital status, type of insurance (social security), residential region, alcohol use, smoking, drinking water source. While education was the only significant factor for women, residential region, housing tenure, smoking and alcohol use were significant for men in models by sex. Conclusion In Turkey, Helicobacter pylori prevalence was found to be very high. Individuals who were women, elderly adults, single, had a high educational level, were living in the fruit growing region, had social security from Emekli Sandigi, were drinking bottled water, non smokers and regular alcohol consumers, were under less risk of Helicobacter pylori infection than others. PMID:24359515

  5. Synergistic mechanism of combinative application of bensulfuron and urea

    International Nuclear Information System (INIS)

    Yu Liuqing; Huang Shiwen; Zhou Hongjie; Ye Guibiao

    1998-01-01

    Nutrient culture study was initiated to examine the synergistic mechanism of combinative application of bensulfuron and urea for weed control. The absorption of 14 C-bensulfuron and their distribution in Lindernia procumbens (Krock.) Philcox were also investigated to determine the variation between two methods (combinative use of 14 C-bensulfuron plus urea and 14 C-bensulfuron alone). One hour after combinative application of 14 C-bensulfuron plus urea, the highest amount of 14 C-activity in L. procumbens were obtained. However, when 14 C-bensulfuron applied alone, total absorption of 14 C-activity was much lower in the 1st hour and then it slowly increased with time. The distribution of 14 C-bensulfuron in root of L. procumbens plant was the highest and that in leaves was the lowest

  6. Utilization of urea micro dose with 14 C in breath test to detect the Helicobacter pylori

    International Nuclear Information System (INIS)

    Chausson, Yvon; Coelho, Luiz Gonzaga V.; Passos, Maria do Carmo F.; Andrade, Angela A.M.; Simal, Carlos J.R.; Paula Castro, Luiz de; Fernandes, M.L.; Yazaki, F.R.

    1995-01-01

    A lower dose is used in the 14 C-urea breath test to detect the Helicobacter pylori (Hp). Such dose produce trivial radiation doses. The results shown that the use of this desirable dose is possible. (author). 4 refs., 1 fig

  7. Transfer of blood urea into the goat colon

    International Nuclear Information System (INIS)

    Engelhardt, W. von; Hinderer, S.

    1976-01-01

    Transfer of body urea into the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously total urea turnover was estimated using 14 C-urea. The transfer of urea into the total gastrointestinal tract (total turnover minus renal excretion) was four times higher with the high-energy - low-protein diet (sugar pulp plus straw) compared with control feeding (hay ad lib.). The transfer of urea into the colon was 8% of the transfer into the total GI tract during control feeding, 14% when food was withheld for 48 hours and 1% during sugar pulp feeding. The transfer into the colon depends mainly on the plasma urea concentration, whereas in the proximal part of the GI tract changes in the permeability of the GI tract wall have a more pronounced influence than plasma urea concentration. (author)

  8. Production of granules of urea, urea-ammonium sulphate and urea-potassium chloride enriched with 15N

    International Nuclear Information System (INIS)

    Bendassolli, J.A.

    1991-01-01

    Using a pearling tower it was possible to produce granulated urea, and granulated mixtures of ammonium sulphate and urea, potassium chloride and urea, Labelled in 15 N. Granulated urea with 1, 2, 3 and 4 mm of diameter was obtained using a system with a heating controller. A low concentration of biuret was observed in the granules produced ( 15 N-Labelled ( 15 NH 4' 15 NH 2 ) with variable proportion of ammonium sulphate and urea. (author)

  9. Urea ammoniation compared to urea supplementation as a method ...

    African Journals Online (AJOL)

    Urea ammoniation compared to urea supplementation as a method of improving the nutritive value of wheat straw for sheep. S.W.P. Cloete, N.M. Kritzinger. Winter Rainfall Region, Eisenburg. The ammoniation of wheat straw by urea in a stack method was in- vestigated and compared to urea supplemented and untreated ...

  10. Final report of the safety assessment of Urea.

    Science.gov (United States)

    2005-01-01

    Although Urea is officially described as a buffering agent, humectant, and skin-conditioning agent-humectant for use in cosmetic products, there is a report stating that Urea also is used in cosmetics for its desquamating and antimicrobial action. In 2001, the Food and Drug Administration (FDA) reported that Urea was used in 239 formulations. Concentrations of use for Urea ranged from 0.01% to 10%. Urea is generally recognized as safe by FDA for the following uses: side-seam cements for food contact; an inhibitor or stabilizer in pesticide formulations and formulations applied to animals; internal sizing for paper and paperboard and surface sizing and coating of paper and paper board that contact water-in-oil dairy emulsions, low-moisture fats and oils, moist bakery products, dry solids with surface containing no free fats or oil, and dry solids with the surface of fat or oil; and to facilitate fermentation of wine. Urea is the end product of mammalian protein metabolism and the chief nitrogenous compound of urine. Urea concentrations in muscle, liver, and fetuses of rats increased after a subcutaneous injection of Urea. Urea diffused readily through the placenta and into other maternal and fetal organs. The half-life of Urea injected into rabbits was on the order of several hours, and the reutilization rate was 32.2% to 88.8%. Urea given to rats by a bolus injection or continuous infusion resulted in distribution to the following brain regions: frontal lobe, caudate nucleus, hippocampus, thalamus plus hypothalamus, pons and white matter (corpus callosum). The permeability constant after treatment with Urea of whole skin and the dermis of rabbits was 2.37 +/- 0.13 (x 10(6)) and 1.20 +/- 0.09 (x10(3)) cm/min, respectively. The absorption of Urea across normal and abraded human skin was 9.5% +/- 2.3% and 67.9% +/- 5.6%, respectively. Urea increased the skin penetration of other compounds, including hydrocortisone. No toxicity was observed for Urea at levels as high

  11. Fourier spectroscopy of the 12C2, 13C2, and 12C13C (0-0) swan bands

    International Nuclear Information System (INIS)

    Amiot, C.

    1983-01-01

    The (0-0) band of the C 2 Swan electronic system d 3 Pi/sub g/→a 3 Pi/sub u/ has been recorded by Fourier spectroscopy. The three isotopes species 12 C 2 , 13 C 2 , and 12 C 13 C were investigated. The observed wavenumbers were reduced to molecular parameters using a nonlinear least-square fitting procedure. Well-known perturbations at N' = 47 and N' = 51 again observed in the e 12 C 2 d 3 Pi/sub g/ (v = 0) level. Perturbations of the same kind are present in the 13 C 2 spectrum at N' = 34 and N' = 44,48,52. The 12 C 13 C spectrum exhibits in the observed spectral range a unique perturbation for N' = 41

  12. Bat urea-derived minerals in arid environment. First identification of allantoin, C4H6N4O3, in Kahf Kharrat Najem Cave, United Arab Emirates

    Directory of Open Access Journals (Sweden)

    Philippe Audra

    2017-01-01

    Full Text Available Kahf Kharrat Najem Cave is a small cave in United Arab Emirates (UAE that hosts a bat colony which is the source of guano deposits and peculiar centimeter-long yellowish stalactites. The mineralogy and geochemistry of these deposits were analyzed using powder X-ray diffraction (XRD, energy dispersive X-ray spectroscopic microanalysis (EDX, scanning electron microscope (SEM, and stable isotope composition (δ13C and δ15N. Urea CO(NH22 was found to be the main compound of these stalactites, while allantoin C4H6N4O3 was found to be an accessory urea byproduct. This paper is the first to mention allantoin in a cave environment. We also identified rare sulfate minerals (aphthitalite, alunite and phosphates that probably correspond to the archerite-biphosphammite series. The occurrence of these rare bat-related minerals is due to the extremely dry conditions in the cave, which accounts for the extraordinary preservation of the guano deposits and allows for the crystallization of these very soluble minerals.

  13. Desarrollo de una formulación estable de ureasa líquida para la determinación de urea en suero

    Directory of Open Access Journals (Sweden)

    Lisandra García Borges

    Full Text Available Introducción: la determinación de urea en suero reviste gran importancia para el diagnóstico clínico de diversas afecciones de origen renal. Los métodos más aplicados para este fin implican el uso de la enzima ureasa por su alta especificidad en la hidrólisis de este analito, entre los cuales el método de Berthelot, emplea la ureasa en el primer paso de la reacción, seguido de una reacción colorimétrica del amoníaco liberado. La presentación de la ureasa en forma líquida es uno de los elementos que hacen más sencillo este proceso, de fácil y rápida ejecución con resultados confiables. Objetivo: desarrollar una solución de ureasa estable, como componente del juego de diagnosticador de urea en suero. Métodos: se diseñó y optimizó la formulación teniendo en cuenta: la concentración de la enzima, las soluciones buffer, los preservos y los compuestos orgánicos polihidroxilados para lograr un producto en forma líquida estable. Se evaluó la especificidad, precisión, linealidad, exactitud (comparación de métodos y la sensibilidad del método; así como la estabilidad en vida de estante de 2 a 8 °C, por un período de 18 meses. Resultados: se logró un reactivo líquido estable (> 12 meses de 2 a 8 °C, donde el método analítico resultó ser específico y lineal hasta 30 mmol/L de urea (r²= 0,999, sensible, preciso coeficiente de variación, CV< 3 % y exacto (r³ 0,999, satisfactorio para el uso al que se destina el producto, con calidad analítica comparable con los existentes en el mercado. Conclusiones: el desarrollo de la formulación de ureasa líquida estable, permitirá introducir este componente esencial, en el juego de reactivos de urea que oferta la Industria Nacional al Sistema de Salud de acuerdo con los requisitos vigentes (Reg. 8-2001 para su comercialización.

  14. Frequency of helicobacter pylori infection using /sup 13/C-UBT in asymptomatic individuals of Barakaho, Islamabad, Pakistan

    International Nuclear Information System (INIS)

    Rasheed, F.; Ahmad, T.; Bilal, R.

    2011-01-01

    High frequency of Helicobacter (H.) pylori infection has been reported in Pakistan mainly for dyspeptic patients, while the published data is inadequate regarding asymptomatic population. The non-invasive /sup 13/C urea breath test (UBT) was used to determine the frequency of H. pylori infection in 516 asymptomatic individuals and to find out its association with gender and age. Overall prevalence was 74.4% (384/516) while 63.5% (113/178) children were positive for 13C-UBT and the percentage increased with age in both the genders with significantly higher prevalence in adolescents (p=0.003) and adults (p < 0.001). Moreover, there was non-significant difference between the prevalence of H. pylori infection in males and females in all age categories. The reported high frequency of H. pylori infection warrants further studies to identify epidemiological and environmental risk factors. (author)

  15. The clinical value of 14C-urea breath test for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    Zhang Shuwen; Zhang Yongxian; Zhang Jinming; Ding Yong; Shao Mingzhe; Liu Zilai; Tian Jiahe

    2003-01-01

    The purpose of this study is to evaluate a rapid microdose 14 C-urea breath test ( 14 C-UBT) with a simplified protocol for detecting the infection of helicobacter pylori (HP). 244 fasting patients with upper gastrointestinal symptoms undergo the 14 C-UBT and 124 cases appear positive. 89 patients of those undergo upper gastrointestinal endoscopy and confirmed as HP infection. The sensitivity and specificity of the 14 C-UBT is 100% when compared with the endoscopy. The test has good diagnostic accuracy with minimal radiation exposure and low cost. Thus, the test is reliable, safe, convenient and cost-effective to clinical use

  16. 1,3-Disubstituted Ureas Functionalized with Ether Groups are Potent Inhibitors of the Soluble Epoxide Hydrolase with Improved Pharmacokinetic Properties

    OpenAIRE

    Kim, In-Hae; Tsai, Hsing-Ju; Nishi, Kosuke; Kasagami, Takeo; Morisseau, Christophe; Hammock, Bruce D.

    2007-01-01

    Soluble epoxide hydrolase (sEH) is a therapeutic target for treating hypertension and inflammation. 1,3-Disubstituted ureas functionalized with an ether group are potent sEH inhibitors. However, their relatively low metabolic stability leads to poor pharmacokinetic properties. To improve their bioavailability, we investigated the effect of incorporating various polar groups on the ether function on the inhibition potencies, physical properties, in vitro metabolic stability, and pharmacokineti...

  17. Synthesis of [2-13C, 2-14C] 2-aminoethanol, [1-13C, 1-14C] 2-chloroethylamine, N,N'-bis([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(BCNU) and N-([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(CNU)

    International Nuclear Information System (INIS)

    Narayan, R.; Chang, C-j.

    1982-01-01

    [2- 13 C, 2- 14 C]2-Aminoethanol hydrochloride was prepared in good yield from Na*CN in a two step sequence by first converting the Na*CN to OHCH 2 *CN and then reducing the nitrile directly with a solution of borane-tetrahydrofuran complex. The reaction procedure was simple and the pure product could be obtained readily. Using this specifically labelled precursor, the synthesis of [1- 13 C, 1- 14 C]2-chloroethylamine hydrochloride, N-([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(CNU) and N,N'-bis([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(BCNU) in good yield without isotope scrambling was also reported. (author)

  18. Effect of urea inclusion in diets containing corn dried distillers grains on feedlot cattle performance, carcass characteristics, ruminal fermentation, total tract digestibility, and purine derivatives-to-creatinine index.

    Science.gov (United States)

    Ceconi, I; Ruiz-Moreno, M J; DiLorenzo, N; DiCostanzo, A; Crawford, G I

    2015-01-01

    Increased availability of rapidly fermentable carbohydrates and a great proportion of corn-derived CP in the diet may result in a degradable intake protein (DIP) deficit. Therefore, ruminal DIP deficit may result from high dietary inclusion of processed corn grain and small to moderate inclusion of corn distillers grains (DG). Two experiments were conducted to evaluate the effect of increasing dietary DIP concentration through the inclusion of urea on feedlot cattle performance, carcass characteristics, ruminal fermentation, total tract digestibility, and purine derivatives-to-creatinine (PDC) index. In Exp. 1, 42 steers (428 ± 5 kg initial BW) were assigned randomly to 1 of 3 diets containing (DM basis) 0 (control [CON]), 0.4 (low urea [LU]), or 0.6% urea (high urea [HU]) to provide 6.4, 7.5, or 8.0% dietary DIP, respectively, and 12% high-moisture corn (HMC), 20% corn dried DG with solubles (DDGS), 10% ryegrass haylage, 2.9% dry supplement, and dry-rolled corn (DRC). Steers were fed ad libitum once daily using a Calan gate system. Carcass-adjusted final BW and DMI were similar among treatments (P ≥ 0.58). Carcass-adjusted ADG was greater (P ≤ 0.04) for the HU diet compared with the LU and CON diets and was similar (P = 0.73) between the LU and CON diets. Carcass-adjusted G:F was greater (P = 0.03) for the HU diet compared with the LU diet, tended (P = 0.09) to be greater compared with the CON diet, and was similar (P = 0.61) between the LU and CON diets. Carcass characteristics were similar (P ≥ 0.34) among treatments. In Exp. 2, 4 ruminally cannulated steers (347 ± 18 kg initial BW) were randomly assigned to a replicated 2 × 2 Latin square design. Steers were fed the same CON or HU diet used in Exp. 1 ad libitum once daily. Differences in the PDC index were used as indicators of differences in microbial CP synthesis. Ruminal pH, OM intake, and starch and CP digestibility were not affected by treatment (P ≥ 0.13). Digestibility of OM and NDF and

  19. INFLUENCE OF ENVIRONMENTAL AND GENETICAL FACTORS ON UREA CONTENT IN HOLSTEIN BREED COWS MILK

    Directory of Open Access Journals (Sweden)

    Draženko Budimir

    2014-12-01

    Full Text Available The aims of this paper were to determine to which extent the environmental factors (order and stadium of lactation, age with the first calving, calving season, region and herd have the influence on the content of urea in milk, and connection of urea content in milk with other features of milk production with cows. The largest share of urea content in milk was recorded in the first lactation, in the period between 110 and 140 days, when it was around 23.6 mg/100 ml. In the end of the first lactation the average urea content in milk was around 21.6 mg/100 ml. The second lactation is chara¬cterized by somewhat bigger urea content, in the period immediately after calving when the highest values from all tracked lactations was recorded. The age of cows with their first calving also had an impact on urea con¬tent in milk. Cows that calved in the age from 24th to 26th month had the highest value of urea content, being 23.2 mg/100 ml for the stated period. The lowest value of urea content was recorded with cows that calved in the age of 18 months and it was below 20 mg/100 ml. Season of calving also influenced the urea content in milk. In winter season 2004 the lowest values of urea content in milk were recorded while in the autumn sea¬son of the same year the highest urea content in milk was measured (24 mg/100 ml. In the following calving season increase of urea content in milk followed. The differences in urea content in milk were determined between the counties. The highest value of heritabi-lity (0.08 was estimated by the model where, as a comparison group, the interaction between the herds and control day was used. In the research the share of variability was explained by the interaction herd-control day and it was 67%, while 25% of variability of urea con¬tent in milk remained unexplained. This model was used when estimating the breeding values. A model was also tested where the influence of herd was used as a comparison group, and by this

  20. The impact of urea-induced unfolding on the redox process of immobilised cytochrome c.

    Science.gov (United States)

    Monari, Stefano; Millo, Diego; Ranieri, Antonio; Di Rocco, Giulia; van der Zwan, Gert; Gooijer, Cees; Peressini, Silvia; Tavagnacco, Claudio; Hildebrandt, Peter; Borsari, Marco

    2010-11-01

    We have studied the effect of urea-induced unfolding on the electron transfer process of yeast iso-1-cytochrome c and its mutant K72AK73AK79A adsorbed on electrodes coated by mixed 11-mercapto-1-undecanoic acid/11-mercapto-1-undecanol self-assembled monolayers. Electrochemical measurements, complemented by surface enhanced resonance Raman studies, indicate two distinct states of the adsorbed proteins that mainly differ with respect to the ligation pattern of the haem. The native state, in which the haem is axially coordinated by Met80 and His18, displays a reduction potential that slightly shifts to negative values with increasing urea concentration. At urea concentrations higher than 6 M, a second state prevails in which the Met80 ligand is replaced by an additional histidine residue. This structural change in the haem pocket is associated with an approximately 0.4 V shift of the reduction potential to negative values. These two states were found for both the wild-type protein and the mutant in which lysine residues 72, 73 and 79 had been substituted by alanines. The analysis of the reduction potentials, the reaction enthalpies and entropies as well as the rate constants indicates that these three lysine residues have an important effect on stabilising the protein structure in the adsorbed state and facilitating the electron transfer dynamics.

  1. Perspectiva espiritual de la mujer con cáncer

    Directory of Open Access Journals (Sweden)

    Milena Alexandra Galvis-López

    2011-01-01

    Full Text Available Objetivo: comparar la perspectiva espiritual de las mujeres diagnosticadas con cáncer propio de su género (seno, útero, ovarios y de las mujeres diagnosticadas con otros tipos de cáncer. Método: diseño cuantitativo de tipo descriptivo comparativo, de corte transversal. Se empleó una encuesta sociodemográfica para caracterizar la población y la Escala de perspectiva espiritual de Pamela Reed, a la cual se le realizó el análisis de confiabilidad que reportó un alfa de Cronbach de 0,799 en el grupo 1 y 0,763 en el grupo 2. La muestra incluyó a 100 mujeres que se encuentran en tratamiento contra el cáncer. Resultados: la perspectiva espiritual de las mujeres con cáncer propio de su género es moderada al igual que la de las mujeres con otros tipos de cáncer; al hacer la comparación de estos dos grupos no se encontró evidencia estadística que demostrara una diferencia significativa. Discusión: los resultados de este estudio aportan nuevos elementos para el cuidado de las mujeres con enfermedad oncológica y señalan que una perspectiva espiritual moderada puede ser un potencial para su cuidado integral, en el que la enfermera reconozca sus objetivos en el cuidado de la mujer como un ser total, más que el tipo de cáncer que tiene.

  2. Modulation of cadmium-induced phytotoxicity in Cabomba caroliniana by urea involves photosynthetic metabolism and antioxidant status.

    Science.gov (United States)

    Huang, Wenmin; Shao, Hui; Zhou, Sining; Zhou, Qin; Li, Wei; Xing, Wei

    2017-10-01

    Urea is a widespread organic pollutant, which can be a nitrogen source, playing different roles in the growth of submerged macrophytes depending on concentrations, while high cadmium (Cd) concentrations are often toxic to macrophytes. In order to evaluate the combined effect of urea and Cd on a submerged macrophyte, Cabomba caroliniana, the morphological and physiological responses of C. caroliniana in the presence of urea and Cd were studied. The results showed that high concentrations of urea (400mgL -1 ) and Cd (500µmolL -1 ) had negative effects on C. caroliniana. There were strong visible symptoms of toxicity after 4 days of exposure under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. In addition, 400mgL -1 urea and Cd had adverse effects on C. caroliniana's pigment system. Significant losses in chlorophyll fluorescence and photosynthetic rates, as well as Rubisco activity were also observed under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. 400mgL -1 urea markedly enhanced Cd toxicity in C. caroliniana, reflected by a sharp decrease in photosynthetic activity and more visible toxicity symptoms. The results of thiobarbituric acid reactive substances (TBARS) pointed to extreme oxidative stress in C. caroliniana induced under Cd or 400mgL -1 urea exposure. Exogenous ascorbate (AsA) protected C. caroliniana from adverse damage in 400mgL -1 urea, which further corroborated the oxidative stress claim under 400mgL -1 urea. However, results also demonstrated that lower urea concentration (10mgL -1 ) alleviated Cd-induced phytotoxicity by stimulating chlorophyll synthesis and photosynthetic activity, as well as activating the activity of catalase (CAT) and glutathione-S-transferase (GST), which may explain the alleviating effect of urea on C. caroliniana under Cd stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Entry of blood urea into the rumen of the llama

    International Nuclear Information System (INIS)

    Hinderer, S.; Engelhardt, W. von

    1976-01-01

    Transfer of body urea into the temporarily isolated rumen cleaned and filled with a test solution was measured in the llama. Simultaneously urea recirculation into the total gastro-intestinal tract (GI-tract) was estimated using 14 C-urea. The permeability of the rumen wall to urea could be changed significantly. With CO 2 or butyric acid in the test solution, permeability was highest, it was low when food was withheld and when no volatile fatty acids were present in the solution. Changes in the permeability can affect the transfer of blood urea across the rumen wall more extensively than changes in plasma urea concentrations. (author)

  4. Quantitative evaluation of the biosynthetic pathways leading to δ-aminolevulinic acid from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus by analysis of 13C-labeled coproporphyrinogen III biosynthesized from [2-13C]glycine, [1-13C]acetate, and [2-13C]acetate using 13C NMR spectroscopy

    International Nuclear Information System (INIS)

    Katsumi Iida

    2013-01-01

    The biosynthetic pathways leading to δ-aminolevulinic acid (ALA) from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus were quantitatively evaluated by means of feeding experiments with [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate, followed by analysis of the labeling patterns of coproporphyrinogen III (Copro'gen III) (biosynthesized from ALA) using 13 C NMR spectroscopy. Two biosynthetic pathways leading to ALA from glycine via the C5 pathway were identified: i.e., transformation of glycine to l-serine catalyzed by glycine hydroxymethyltransferase, and glycine synthase-catalyzed catabolism of glycine to N 5 , N 10 -methylene-tetrahydrofolic acid (THF), which reacts with another molecule of glycine to afford l-serine. l-Serine is transformed to acetyl-CoA via pyruvic acid. Acetyl-CoA enters the tricarboxylic acid cycle, affording 2-oxoglutaric acid, which in turn is transformed to l-glutamic acid. The l-glutamic acid enters the C5 pathway, affording ALA in A. hyalinus. A 13 C NMR spectroscopic comparison of the labeling patterns of Copro'gen III obtained after feeding of [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate showed that [2- 13 C]glycine transformation and [2- 13 C]glycine catabolism in A. hyalinus proceed in the ratio of 52 and 48 %. The reaction of [2- 13 C]glycine and N 5 , N 10 -methylene-THF, that of glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF generated from the [2- 13 C]glycine catabolism, and that of [2- 13 C]glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF transformed the fed [2- 13 C]glycine to [1- 13 C]acetyl-CoA, [2- 13 C]acetyl-CoA, and [1,2- 13 C 2 ]acetyl-CoA in the ratios of 42, 37, and 21 %, respectively. These labeled acetyl-CoAs were then incorporated into ALA. Our results provide a quantitative picture of the pathways of biosynthetic transformation to ALA from glycine in A. hyalinus. (author)

  5. Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

    Energy Technology Data Exchange (ETDEWEB)

    Porwoll, J P; Leete, E [Minnesota Univ., Minneapolis (USA). Dept. of Chemistry

    1985-03-01

    Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

  6. Synthesis of C-13 labeled vitamin E, [4' a-13C]all-rac-α-tocopherol

    International Nuclear Information System (INIS)

    Urano, Shiro; Muto, Riko; Matsuo, Mitsuyoshi

    1985-01-01

    Vitamin E with a 13 C-labeled isoprenoid side chain, [4' a- 13 C]-all-rac-α-tocopherol, was synthesized by the coupling reaction of 6-4-methoxymethoxy-2-([methyl- 13 C]5-bromo-4-methyl-pent-1-yl)chroman (8) with 3,7-dimethyl-1-(thiazolin-2-yl)thio-2,6-octadiene. Compound 8 was prepared using 2-(4,4-di-ethoxycarbonylbut-1-yl)-6-methoxymethoxy-2,5,7,8-tetramethyl-chroman as a key intermediate and [ 13 C]methyl iodide as a 13 C source. The total yield of the labeled α-tocopherol based on [ 13 C]methyl iodide was 58.7%. (author)

  7. The effect of radioactive iodine treatment on 14C urea breath test results in patients with hyperthyroidism.

    Science.gov (United States)

    Arduc, Ayse; Dogan, Bercem Aycicek; Ozuguz, Ufuk; Tuna, Mazhar Muslim; Gokay, Ferhat; Tutuncu, Yasemin Ates; Isik, Serhat; Aydin, Yusuf; Peksoy, Irfan; Berker, Dilek; Guler, Serdar

    2014-12-01

    Radioactive Iodine therapy (RAIT) plays a major role in the treatment of hyperthyroidism. In addition to the thyroid gland, significant amounts of radioactive iodine are maintained in the stomach. The aim of this study was to determine if RAIT has any effect on Helicobacter pylori infection, based on the C urea breath test (UBT). The study included 85 patients with hyperthyroidism scheduled to undergo RAIT and 69 hyperthyroid subjects in whom methimazole treatment was planned. All subjects had pretreatment-positive UBT results, and the test was repeated on the first and third months after RAIT and methimazole treatment. After a mean RAIT dose of 15 mCi (range, 10-20 mCi), UBT became negative in 13 (15.3%) of 85 patients on the first month and 18 (21.2%) of 85 patients on the third month. All subjects treated with methimazole remained UBT positive on the first and third months of methimazole treatment (100%). Reduction in the number of UBT-positive patients on both the first and the third months after RAIT was statistically significant (P hyperthyroidism etiologies and thyroid autoantibody levels in subjects with UBT that became negative and in subjects with UBT that remained positive were similar in the RAIT group (P > 0.05). Urea breath test negativity rates did not differ according to the radioiodine dose. Our findings indirectly showed that RAIT might have an antimicrobial effect on H. pylori. Clinical applications of this beneficial effect of RAIT on H. pylori should be further evaluated.

  8. Urea metabolism in plants.

    Science.gov (United States)

    Witte, Claus-Peter

    2011-03-01

    Urea is a plant metabolite derived either from root uptake or from catabolism of arginine by arginase. In agriculture, urea is intensively used as a nitrogen fertilizer. Urea nitrogen enters the plant either directly, or in the form of ammonium or nitrate after urea degradation by soil microbes. In recent years various molecular players of plant urea metabolism have been investigated: active and passive urea transporters, the nickel metalloenzyme urease catalyzing the hydrolysis of urea, and three urease accessory proteins involved in the complex activation of urease. The degradation of ureides derived from purine breakdown has long been discussed as a possible additional metabolic source for urea, but an enzymatic route for the complete hydrolysis of ureides without a urea intermediate has recently been described for Arabidopsis thaliana. This review focuses on the proteins involved in plant urea metabolism and the metabolic sources of urea but also addresses open questions regarding plant urea metabolism in a physiological and agricultural context. The contribution of plant urea uptake and metabolism to fertilizer urea usage in crop production is still not investigated although globally more than half of all nitrogen fertilizer is applied to crops in the form of urea. Nitrogen use efficiency in crop production is generally well below 50% resulting in economical losses and creating ecological problems like groundwater pollution and emission of nitric oxides that can damage the ozone layer and function as greenhouse gasses. Biotechnological approaches to improve fertilizer urea usage bear the potential to increase crop nitrogen use efficiency. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

    Energy Technology Data Exchange (ETDEWEB)

    Porwoll, J.P.; Leete, E. (Minnesota Univ., Minneapolis (USA). Dept. of Chemistry)

    1985-03-01

    Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

  10. Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows.

    Science.gov (United States)

    Spek, J W; Bannink, A; Gort, G; Hendriks, W H; Dijkstra, J

    2013-09-01

    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37 kg, 146±29 d in milk, and a milk production of 34.0±3.28 kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154 g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5 g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90 mg of N/dL and 45 g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74 mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable

  11. A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method.

    Science.gov (United States)

    Sampson, E J; Baird, M A; Burtis, C A; Smith, E M; Witte, D L; Bayse, D D

    1980-06-01

    We describe a coupled-enzyme equilibrium method for measuring urea in serum, which is performed on supernates prepared by treating each specimen with Ba(OH)2 and ZnSO4 (Somogyi reagent). Analytical recovery of [14C]urea added to a variety of matrices was essentially complete (mean, 100.6%) for the supernates after precipitation. Nine variables were univariately examined in arriving at the reaction conditions for the method: glutamate dehydrogenase, urease, 2-oxoglutarate, ADP, Tris . HCI, NADH, EDTA, pH, and temperature. The reagent is stable for at least 48 days at--20 degrees C and for 23 days at 4 degrees C. Mean analytical recovery of urea (14 mmol/L) added to seven different specimens (three different matrices) was 100.8%. The analytical linear range of the method extends to 30 mmol of urea per liter. Of 22 potential interferents, only bilirubin at 1 mmol/L (580 mg/L), hemoglobin at 10 g/L, and hydroxyurea at 6 mmol/L showed more than 2% interference. We discuss precision and effects of specimen dilution, and compare results for 100 human serum specimens with those measured for the same specimens with four other urea methods. We examined the effects of measuring a blank, consisting of sample and reagent without urease, with each specimen.

  12. Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

    KAUST Repository

    Lee, Junggil

    2012-10-01

    Urea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.

  13. Cocomplexation of urea and UO22+ in a Schiff base macrocycle: a mimic of an enzyme binding site

    International Nuclear Information System (INIS)

    van Staveren, C.J.; Fenton, D.E.; Reinhoudt, D.N.; van Eerden, J.; Harkema, S.

    1987-01-01

    As part of the authors work on the complexation of neutral molecules by macrocyclic ligands, they are particularly interested in the complexation of urea. They have shown that urea can form complexes with (aza-)18-crown but the association constants of these complexes in water are very small (18-crown-6-urea, log K/sub s/ = 0.1). Protonation of urea effects stronger binding especially when the crown ether is sufficiently large to form an encapsulated complex (e.g., the complex benzo-27-crown-9-urea-HClO 4 ). Protonation of the weakly basic urea (pK/sub a/ = 0.1, water, 25 0 C) requires strongly acidic conditions and to avoid this they have introduced a covalently linked carboxylic group in the cavity of the macrocycle. A strong hydrogen bond of urea with 2-carboxyl-1,3-xylyl-30-crown-9 results in an encapsulated complex. The concept of using an electrophilic center to bind urea in the cavity of a crown ether proved to be a more general concept. A metal cation can serve as the electrophile as was shown by the isolation and single-crystal X-ray analysis of the 2,6-pyrido-27-crown-9-urea-LiClO 4 (1:2:1) complex in which one of the urea molecules is encapsulated. In an effort to bind an electrophilic metal ion in the crown ethers irreversibly they have concentrated their work on macrocycles of type 1, since the strong binding of quadridentate (salen type) Schiff bases with soft metal ions is well-known

  14. Contamination by Helicobacter pylori measured by the 13C-Urea-Breath-Test and nutritional status of children with chronic diarrhoea syndrome in Havana City

    International Nuclear Information System (INIS)

    Hernandez-Triana, M.H.; Cabrera, A.; Sanchez, M. A.; Herrera, X.; Pawong, M.; Moreno, R.; Reyes, D.; Serrano, G.; Diaz, M.E.

    2002-01-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori (Hp) is discussed in pathogenic relation to gastritis, duodenal ulcer, chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94 % in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer, stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the 13C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values

  15. Effect of urea supplemented and urea treated straw based diet on milk urea concentration in crossbred Karan-Fries cows

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Sirohi

    2010-01-01

    Full Text Available The study was undertaken to evaluate the effect of urea supplemented and urea treated straw based diet on milk ureaconcentration. Six multiparous crossbred Karan-Fries (Holstein Friesian ✕ Tharparkar cows were blocked into threegroups of nearly equal body weight, DIM, milk yield and milk fat content and were randomized into a 3 ✕ 3 Latin squaredesign with 3-week period. Three experimental diets were fed to the animals. Composition of these diets were: Diet 1green maize, wheat straw and concentrate mixture; Diet 2 green maize, wheat straw, concentrate mixture (urea supplementedand molasses; Diet 3 green maize (4 % of total DM, 4 % urea treated wheat straw and concentrate mixture.Intake of DM and CP did not vary across the diets. Intake of digestible crude protein (DCP was found significantlyhigher in diet 2, while ME and NEL intakes were found significantly lower in diet 3 but did not differ between diets 1and 2. Average milk and plasma urea concentrations (mg dl-1 were found 29.2 ± 2.6, 45.3 ± 0.9, 34.5 ± 2.3 and 28.9± 2.4, 36.6 ± 1.4, 33.9 ± 2.2, respectively in diet 1, diet 2 and diet 3. Urea concentrations in morning milk sampleswere found significantly lower than noon or evening samples in all the three diets. Concentrations of urea in milk andplasma were found closely correlated (r = 0.94 and the regression equation developed was, plasma urea = 8.90 (.89+ .79 (.02 milk urea. Intake (g of DCP than CP, per unit (MCal of ME was found more closely associated with milk ureaconcentration. The study revealed that urea supplementation and urea treated straw based diet increased urea concentrationsignificantly in milk and plasma. Morning milk urea values that estimated at a time gap of 15 hr since last majorfeeding may be considered as the lowest level and can be used for interpretation to monitor feeding adequacy or reproductiveperformances in dairy cows.

  16. Synthesis of 1-13C-1-indanone and 2-13C-1,2,3,4-tetrahydroquinoline

    International Nuclear Information System (INIS)

    Pickering, R.E.; Wysocki, M.A.; Eisenbraun, E.J.

    1985-01-01

    The synthesis of 2- 13 C-1,2,3,4-tetrahydroquinoline (5) via 1- 13 C-3-phenylpropanoic acid (1), 1- 13 C-1-indanone (2), 1- 13 C-1-indanone hydrazone (3) and 2- 13 C-3,4-dihydro-2(1H)-quinolinone (4) proceeded in 78, 96, 95, 79, and 85% individual yields respectively for 1, 2, 3, 4, 5 and 61% overall yield of the latter from 1. (author)

  17. Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.

    Science.gov (United States)

    Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

    2011-08-01

    Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

  18. Role of rumen butyrate in regulation of nitrogen utilization and urea nitrogen kinetics in growing sheep.

    Science.gov (United States)

    Agarwal, U; Hu, Q; Baldwin, R L; Bequette, B J

    2015-05-01

    Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling on the basis of increased expression of urea transporter in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concentrations on N balance, urea kinetics and rumen epithelial proliferation. Wether sheep (n= 4), fitted with a rumen cannula, were fed a pelleted ration (∼165 g CP/kg DM, 10.3 MJ ME/kg DM) at 1.8 × ME requirement. In Exp. 1, sheep were infused intraruminally with either an electrolyte buffer solution (Con-Buf) or butyrate dissolved in the buffer solution (But-Buf) during 8-d periods in a balanced crossover design. In Exp. 2, sheep were infused intraruminally with either sodium acetate (Na-Ac) or sodium butyrate (Na-But) for 9 d. All solutions were adjusted to pH 6.8 and 8.0 in Exp. 1 and 2, respectively, and VFA were infused at 10% of ME intake. [15N2] urea was continuously infused intravenously for the last 5 d of each period, and total urine and feces were collected. In Exp. 1, 2H5-phenylalanine was continuously infused intravenously over the last 12 h, after which a biopsy from the rumen papillae was taken for measurement of fractional protein synthesis rate (FSR). Butyrate infusion treatments increased (P = 0.1 in Exp. 1; P urea entry (synthesis) rate was reduced ( urea kinetics were not altered by But-Buf compared with Con-Buf. These studies are the first to directly assess the role of butyrate in urea recycling and its effects on rumen papillae protein turnover in growing lambs. Under the feeding conditions used and the rate of continuous butyrate infusion into the rumen in the present studies, butyrate does not affect overall N retention in growing sheep. However, butyrate may play a role in the redistribution of urea N fluxes in the overall scheme of N metabolism.

  19. Effect of rumen-degradable intake protein supplementation on urea kinetics and microbial use of recycled urea in steers consuming low-quality forage.

    Science.gov (United States)

    Wickersham, T A; Titgemeyer, E C; Cochran, R C; Wickersham, E E; Gnad, D P

    2008-11-01

    We evaluated the effect of increasing amounts of rumen-degradable intake protein (DIP) on urea kinetics in steers consuming prairie hay. Ruminally and duodenally fistulated steers (278 kg of BW) were used in a 4 x 4 Latin square and provided ad libitum access to low-quality prairie hay (4.9% CP). The DIP was provided as casein dosed ruminally once daily in amounts of 0, 59, 118, and 177 mg of N/kg of BW daily. Periods were 13 d long, with 7 d for adaptation and 6 d for collection. Steers were in metabolism crates for total collection of urine and feces. Jugular infusion of (15)N(15)N-urea, followed by determination of urinary enrichment of (15)N(15)N-urea and (14)N(15)N-urea was used to determine urea kinetics. Forage and N intake increased (linear, P Urea synthesis was 19.9, 24.8, 42.9, and 50.9 g of urea-N/d for 0, 59, 118, and 177 mg of N/kg of BW daily (linear, P = 0.004). Entry of urea into the gut was 98.9, 98.8, 98.6, and 95.9% of production for 0, 59, 118, and 177 mg of N/kg of BW daily, respectively (quadratic, P = 0.003). The amount of urea-N entering the gastrointestinal tract was greatest for 177 mg of N/kg of BW daily (48.6 g of urea-N/d) and decreased (linear, P = 0.005) to 42.4, 24.5, and 19.8 g of urea-N/d for 118, 59, and 0 mg of N/kg of BW daily. Microbial incorporation of recycled urea-N increased linearly (P = 0.02) from 12.3 g of N/d for 0 mg of N/kg of BW daily to 28.9 g of N/d for 177 mg of N/kg of BW daily. Provision of DIP produced the desired and previously observed increase in forage intake while also increasing N retention. The large percentage of urea synthesis that was recycled to the gut (95.9% even when steers received the greatest amount of DIP) points to the remarkable ability of cattle to conserve N when fed a low-protein diet.

  20. Distribution and excretion of α-naphthylthio-[14C]urea in Albino rats

    International Nuclear Information System (INIS)

    Patil, T.N.; Radhakrishnamurty, R.

    1977-01-01

    α-naphthylthio-( 14 C) urea was synthesised by allowing potassium ( 14 C)thiocyanate to react with α-naphthylamine. Its distribution and excretion were studied in Albino rats following the administration of this rodenticide. Considerable radioactivity observed in liver and kidney, increased till 8 hr and later decreased. About 80% of the activities present in serum and pleural effusion were found in the respective albumin fractions. Approximately 40% of the dose administered was excreted in urine and less than 1% in faeces in 20 hr. About 36% of the total urinary activity was recovered as unchanged compound and the rest was distributed in three metabolites with low Rsyb(f) values. Decrease in cytochsome P-450 content and activities of N, N-dimethylaniline demethylase, aryl 4-hydroxylase and reduced NAD dehydrogenase were observed in α-naphthylathiourea-treated rats. (author)

  1. Adición de melaza deshidratada y urea en ensilados de rastrojos de piña.

    Directory of Open Access Journals (Sweden)

    Sofía Rodríguez-Chacón

    2014-07-01

    Full Text Available El objetivo de esta investigación fue determinar el efecto de urea y melaza deshidratada con minerales en ensilados de rastrojos de piña. El trabajo fue realizado en los meses de abril y junio del año 2010, con base en la técnica de microsilos en bolsas de 1 kg. Se establecieron cuatro tratatmientos de urea (0, 0,5, 1, 1,5% p/p, cuatro de melaza deshidratada con minerales (MDM (0, 0,2, 0,4, 0,6 % p/p y un único nivel de inóculo bacterial (1 l/t para todos. La inclusión de MDM aumentó de forma significativa el pH (2,84 contra 8,23 y las cenizas (8,1 contra 16,1% MS pero disminuyó la digestibilidad in vitro de la materia seca (67,3 contra 54,0%, conforme se incrementó este aditivo. Al aumentar el nivel de urea en las mezclas ensiladas se afectaron de forma significativa y proporcional las variables de pH, nitrógeno amoniacal (N-NH3 (3,87 contra 7,10% NH3/NT y proteína cruda (PC (8,2 contra 18,3% MS. Estos aditivos no afectaron la concentración de materia seca, ni el contenido de la fracción fibrosa de los materiales ensilados. El contenido de carbohidratos no fibrosos (CNF se elevó conforme aumentó el nivel de MDM, sin embargo conforme se incrementó el nivel de urea en la mezcla, el valor de esta fracción se redujo.

  2. Cardioimplante con células madre. Evolución a 43 meses

    Directory of Open Access Journals (Sweden)

    Jorge C. Trainini

    2009-01-01

    Full Text Available RESUMENIntroducciónLa insuficiencia cardíaca como consecuencia del infarto de miocardio es uno de los problemasmayores que afronta la cardiología. La disminución de cardiomiocitos y la formación deescaras fibróticas no funcionales producida por el infarto ocasionan un daño irreversiblepara la función cardíaca. Estudios recientes han demostrado que el trasplante de célulasmadre de la médula ósea en el miocardio no viable ofrece una nueva posibilidad de restauración de la disfunción cardíaca en los corazones infartados. Estos datos preliminares indicanla factibilidad del implante de células madre de la médula ósea en miocardiopatíasisquémico-necróticas.ObjetivosEsta investigación tiene por objetivo comprobar la factibilidad y la seguridad delcardioimplante de células madre de la médula ósea en pacientes con disfunción ventricularsecundaria a secuelas necróticas y evaluar los cambios clínicos y en la motilidad segmentariade las áreas no viables durante el seguimiento alejado.Material y métodosNuestra experiencia incluye trece pacientes (sexo masculino, edad 53,6 ± 10,3 años con unpromedio de seguimiento de 43 meses. Los segmentos fibróticos comprometidos fueron entotal 88 (6,77 por paciente. Se realizó cirugía coronaria concomitante en áreas remotas,viables e isquémicas. Los pacientes fueron estudiados con ecocardiografía con dobutamina,color cinesis y ventriculografía radioisotópica.ResultadosLa suspensión celular inyectada contenía 0,7% ± 0,4% de células CD34+ con una viabilidadmayor del 95%. Se implantaron mediante 33,07 ± 8,2 inyecciones durante cirugíacoronaria, por vía epicárdica con un promedio de 5,93 ± 2,2 ml de solución en áreas acinéticasy metabólicamente no viables. No hubo complicaciones hospitalarias. La clase funcional(NYHA pasó de 2,4 ± 0,5 a 1,1 ± 0,3 (p < 0,0003, la fracción de eyección se incrementódesde el 26,4% ± 8,6% al 34,6% ± 13% (p < 0,001. El diámetro diast

  3. Efecto de la urea sobre la viscosidad de soluciones acuosas de aminoácidos

    Directory of Open Access Journals (Sweden)

    Carmen María Romero

    2010-07-01

    Full Text Available Se midió a 25.0° la viscosidad de soluciones de glicina, dl-alanina, norvalina, dlvalina, norleucina y 1-leucina usando como solventes soluciones acuosas de urea 0.5 y 2.0 M. Los valores obtenidos para los coeficientes B de viscosidad muestran que aún a bajas concentraciones la urea ejerce un efecto disruptor sobre la estructura del agua y sugieren que a- aminoácidos con más de 4 carbonos en el grupo apolar pueden presentar efectos de doblez de cadena por interacciones hidrofóbicas.

  4. Urea hydrolysis and ammonia volatilization from some urea based fertilizers applied to rice

    International Nuclear Information System (INIS)

    Misra, C.; Jena, D.; Bandyopadhyay, K.K.; Schepers, J.S.

    1995-01-01

    Field experiments were carried out in replicated microplots (1 m x 1 m) with rice (cv. Pathara) to study urea hydrolysis using several urea based N-fertilizer sources. Results indicated highly significant urea based N-fertilizers, among which urea super granule (USG) and prilled urea (PU) (applied in two splits) could be rated as the most efficient sources of N. Based on measured ammonia volatilization loss, NH 2 -N concentration in flood water and soil solution (following fertilizer application); urea hydrolysis was observed to be faster in the case of PU, USG, PU + ECC (encapsulated calcium carbide) and UNP (urea nitro phosphate) (19-19-0) than in the case of GCU (gypsum coated urea) and UNP (27-9-0) treatments. Based on the 15 N tagged prilled urea experiment, it is observed that about 24 per cent of fertilizer nitrogen was utilized by the crop in closed system as compared to 18 per cent in natural free system. (author). 5 refs., 2 figs., 4 tabs

  5. Leyenda áurea, un código estético al servicio de lo grotesco

    Directory of Open Access Journals (Sweden)

    García Pascual, Raquel

    2005-06-01

    Full Text Available José María Rodríguez Méndez is a well known creator of the Post-Civil War Drama, but his work has not been studied as the whole. The main subject that concern us is to point out that Leyenda áurea, written in 1998, helps us to see how the writer is used to employ a carnivalesque code. Far from his neosainetes Bodas que fueron famosas or Historia de unos cuantos, this piece focus on a new dramatic manner; we'll like to underline the original language its characters display.José María Rodríguez Méndez es un dramaturgo canónico encuadrado en el teatro español de posguerra, pero su obra no ha sido estudiada de forma global. De la mano de Leyenda áurea, escrita en 1998, nos gustaría demostrar cómo su autor ha venido desplegando en sus últimas obras un código carnavalesco. Lejos de sus neosainetes Bodas que fueron famosas o Historia de unos cuantos, esta pieza es una muestra de su nuevo estilo dramático; pretendemos poner de relieve el original uso idiomático que exhiben sus personajes.

  6. pH-switchable electrochemical sensing platform based on chitosan-reduced graphene oxide/concanavalin a layer for assay of glucose and urea.

    Science.gov (United States)

    Song, Yonghai; Liu, Hongyu; Tan, Hongliang; Xu, Fugang; Jia, Jianbo; Zhang, Lixue; Li, Zhuang; Wang, Li

    2014-02-18

    A facile and effective electrochemical sensing platform for the detection of glucose and urea in one sample without separation was developed using chitosan-reduced graphene oxide (CS-rGO)/concanavalin A (Con A) as a sensing layer. The CS-rGO/Con A with pH-dependent surface net charges exhibited pH-switchable response to negatively charged Fe(CN)6(3-). The principle for glucose and urea detection was essentially based on in situ pH-switchable enzyme-catalyzed reaction in which the oxidation of glucose catalyzed by glucose oxidase or the hydrolyzation of urea catalyzed by urease resulted in a pH change of electrolyte solution to give different electrochemical responses toward Fe(CN)6(3-). It was verified by cyclic voltammograms, differential pulse voltammograms, and electrochemical impedance spectroscopy. The resistance to charge transfer or amperometric current changed proportionally toward glucose concentration from 1.0 to 10.0 mM and urea concentration from 1.0 to 7.0 mM. On the basis of human serum experiments, the sensing platform was proved to be suitable for simultaneous assay of glucose and urea in a practical biosystem. This work not only gives a way to detect glucose and urea in one sample without separation but also provides a potential strategy for the detection of nonelectroactive species based on the enzyme-catalyzed reaction and pH-switchable biosensor.

  7. Urea in Milk

    OpenAIRE

    Projectsatbangalore

    2017-01-01

    This paper describes the design of a low-cost, portable instrument using CO2 and NH3 gas sensor technology to quantify and differentiate milk samples containing excess urea. Milk containing urea, in presence of urease enzyme hydrolyses urea to form ammonia and carbon dioxide.

  8. Study for the charge symmetric systems, 12C+13N and 12C+13C with the orthogonalized coupled-reaction-channel method

    International Nuclear Information System (INIS)

    Imanishi, B.; Denisov, V.; Motobayashi, T.

    1996-10-01

    The charge-symmetric scattering systems, 12 C+ 13 N and 12 C+ 13 C have been investigated by using the orthogonalized coupled-reaction-channel (OCRC) method with the basis functions of the elastic, inelastic and transfer channels defined by the single-particle states, 1p1/2, 2s1/2, 1d5/2 and 1d3/2 of the valence nucleon in 13 N or 13 C. The data of the elastic scattering of 13 N on 12 C measured by Lienard et al. have been explained consistently with the data of the elastic and inelastic scattering of the 12 C+ 13 C system. The CRC effects both on the above systems are very strong, although those on the 12 C+ 13 N system are fairly weaker than the 12 C+ 13 C system. The role of the highly excited single-particle states 1d3/2 is particularly important in the formation of a specific CRC scheme, i.e., the formation of the covalent molecules due to the hybridization caused by the mixing of the different parity single-particle states. The fusion cross sections of the 12 C+ 13 C system at energies below the Coulomb barrier are strongly enhanced as a result of the strong CRC effects as compared with those of the 12 C+ 12 C system, while in 12 C+ 13 N system the enhancement of the sub-barrier fusion has not been observed. The above absorption mechanism for the 12 C+ 13 C system explains the lack of the molecular-resonance phenomena observed in the 12 C+ 12 C system. We check the effects of the dipole (E1) transition of the valence nucleon in 13 N (and also in 13 C) due to the core-core Coulomb interaction in the scattering at sub-barrier energies. The effects are not appreciable. (author)

  9. Multisite Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    Directory of Open Access Journals (Sweden)

    Pedro A. Gómez Damián

    2014-01-01

    Full Text Available Hyperpolarized 13C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1-13C]pyruvate and downstream metabolites [1-13C]alanine, [1-13C]lactate, and [13C]bicarbonate can be achieved through kinetic modeling. Since pyruvate interacts dynamically and simultaneously with its downstream metabolites, the purpose of this work is the determination of parameter values through a multisite, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multisite model to time-domain dynamic metabolite data. The results for different pyruvate doses were compared with those of different two-site models to evaluate the hypothesis that for identical data the uncertainty of a model and the signal-to-noise ratio determine the sensitivity in detecting small physiological differences in the target metabolism. In comparison to the two-site exchange models, the multisite model yielded metabolic conversion rates with smaller bias and smaller standard deviation, as demonstrated in simulations with different signal-to-noise ratio. Pyruvate dose effects observed previously were confirmed and quantified through metabolic conversion rate values. Parameter interdependency allowed an accurate quantification and can therefore be useful for monitoring metabolic activity in different tissues.

  10. [Separation of gamma linolenic acid from evening primrose oil with urea inclusion--orthogonal experiment of optimizing technological parameters and observation of urea inclusion compound I].

    Science.gov (United States)

    Wang, Hua; Ling, Man; Xue, Gang; Liu, Fengxia; Guo, Shuxian

    2010-05-01

    The influence on the urea inclusion compound under different conditions (allocated proportion, time of inclusion, temperature of inclusion) were studied through the orthogonal test, and theoretical reference of urea inclusion process for further optimization wound be offered. The orthogonal experiment was adopted, and microscope was used to observe the shape, aperture size of the urea inclusion compound under different technological parameters, the GC was employed to inspect the purity of GLA. The results indicated that the ratio of fatty acids and urea, inclusion of temperature, time of inclusion had great effect on urea inclusion compound. The three factors and its interactions significantly affected the purity of GLA. The results also showed that the best process was that the ratio of fatty acids and urea was 1 : 3, temperature of inclusion was--15 degrees C, time of inclusion was 24 h. Under the best condition, the purity of GLA reach up to 95.575 9%; and it is feasible to observe the shape and the amount of the urea inclusion compound to reflect and guide the urea inclusion technology.

  11. Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer

    Science.gov (United States)

    Guinn, Emily J.; Pegram, Laurel M.; Capp, Michael W.; Pollock, Michelle N.; Record, M. Thomas

    2011-01-01

    To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients Kp for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. Kp values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH—amide O and amide NH—amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or Kp values. PMID:21930943

  12. Urea metabolism in Zebu calves fed on diets of dierent crude protein contents

    International Nuclear Information System (INIS)

    Sharma, P.K.; Singh, U.B.; Verma, D.N.; Lal, M.; Ranjhan, S.K.

    1974-01-01

    The entry rates of urea into the body pool of urea have been estimated in Zebu calves using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine over 24 h and urea content. The calves were fed 2 levels of crude protein, i.e., 25 percent lower and 25 percent higher than NRC recommendations. Results show that the degradation of urea is significantly better in animals given rations low in crude protein contents. (M.G.B.)

  13. Syntheses of DL-[2-13C]leucine and its use in the preparation of [3-DL-[2-13C]leucine]oxytocin and [8-DL-[2-13C]leucine]oxytocin

    International Nuclear Information System (INIS)

    Viswanatha, V.; Larsen, B.; Hruby, V.J.

    1979-01-01

    DL-[2- 13 C]Leucine was prepared by condensing the sodium salt of ethyl acetamido-[2- 13 C]cyanoacetate with isobutylbromide in hexamethylphosphoroustriamide followed by acid hydrolysis. N-BOC-DL-[2- 13 C]Leucine was prepared and incorporated into [8-DL-[2- 13 C]leucine]oxytocin by total synthesis. The 13 C-labeled hormone derivative [8-[2- 13 C]leucine]oxytocin was separated from its 8-position diastereoisomer by partition chromatography. The specifically 13 C-labeled peptide hormone diastereoisomeric analog [3-DL-[2- 13 C]leucine]oxytocin also was prepared by solid phase peptide synthesis. No suitable solvent system for partition chromatography separation of the latter diastereoisomeric peptide mixture could be found. However an excellent preparative separation of the diastereoisomers could be obtained by reverse phase high pressure liquid chromatography on a partisil 10 M9 ODS column using the solvent system 0.05 M ammonium acetate (pH 4.0), acetonitrile (81:19, v/v) to give pure [3-[2- 13 C]leucine]oxytocin and [3-D-[2- 13 C]leucine]oxytocin. An excellent separation of [8-[2- 13 C]leucine]oxytocin and the corresponding delata-D-leucine diastereoisomer derivative could also be accomplished by high pressure liquid chromatography. (author)

  14. In vivo dynamic turnover of cerebral 13C isotopomers from [U- 13C]glucose

    Science.gov (United States)

    Xu, Su; Shen, Jun

    2006-10-01

    An INEPT-based 13C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic 13C isotopomer turnover from intravenously infused [U- 13C]glucose in a 211 μL voxel located in the adult rat brain. The INEPT-based 1H → 13C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B 1 inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with 1JC4C5 = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with 1JC3C4 = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.

  15. Influence of urea application on growth, yield and mineral uptake in ...

    African Journals Online (AJOL)

    A pot experiment was conducted in a wire netting green house in order to assess the beneficial effect of urea on corn cultivars (C-20 and C-79) differing in yield production. Corn plants were grown in loam soil with alkaline in reaction. Application of varying urea levels did not change the physico-chemical properties of soil.

  16. Síntesis y actividad citotóxica de conjugados de la uridina con triterpenos en células de cáncer de mama

    Directory of Open Access Journals (Sweden)

    Jhon Fernando Berrío Escobar

    Full Text Available Objetivos: Sintetizar conjugados del acetónido de la uridina con triterpenos (colesterol y 3β-5α,8α-endoperoxido-colest-6-en-3-ol y ácido succínico como puente. Métodos: Se preparó el acetónido de la uridina en acetona mediante catálisis ácida. Se prepararon los succinatos de los esteroles con anhídrido succínico y catalizador nucleofílico 4-N,N-dimetilamino-piridina (DMAP. Los conjugados 1 y 2 se sintetizaron mediante la esterificación de Steglich, con agente de acoplamiento N,N'-diciclohexilcarbodiimida (DCCy DMAP. Los compuestos se caracterizaron por espectroscopia de RMN (¹H RMN y 13C RMN y espectrometría de masas. Los derivados se evaluaron sobre líneas celulares de ovario de hámster chino (CHO-K1 y de cáncer de mamá (MCF-7. Resultados: Se obtuvieron derivados conjugados del acetónido de la uridina con dos triterpenos con rendimientos superiores al 80%. Los conjugados de uridina con triterpenos no presentaron inhibición significativa de la viabilidad celular sobre las líneas celulares MCF-7 y CHO-K1, tampoco se evidenció una relación dosis-respuesta para los compuestos evaluados. Conclusiones: El método de esterificación con agentes de acoplamiento permitió obtener conjugados de la uridina con triterpenos empleando el ácido succínico como puente. Sin embargo los derivados de uridina obtenidos no presentaron actividad citotóxica significativa (p<0,05 sobre las líneas celulares evaluadas.

  17. Effect of dietary nitrogen content and intravenous urea infusion on ruminal and portal-drained visceral extraction of arterial urea in lactating Holstein cows.

    Science.gov (United States)

    Kristensen, N B; Storm, A C; Larsen, M

    2010-06-01

    Urea extraction across ruminal and portal-drained visceral (PDV) tissues were investigated using 9 rumen-cannulated and multi-catheterized lactating dairy cows adapted to low-N (12.9% crude protein) and high-N (17.1% crude protein) diets in a crossover design. The interaction between adaptation to dietary treatments and blood plasma concentrations of urea was studied by dividing samplings into a 2.5-h period without urea infusion followed by a 2.5-h period with primed continuous intravenous infusion of urea (0.493+/-0.012 mmol/kg of BW per h). Cows were sampled at 66+/-14 and 68+/-12 d in milk and produced 42+/-1 and 36+/-1 kg of milk/d with the high-N and low-N diets, respectively. The arterial blood urea concentration before urea infusion was 1.37 and 4.09+/-0.18 mmol/L with low-N and high-N, respectively. Dietary treatment did not affect the urea infusion-induced increase in arterial urea concentration (1.91+/-0.13 mmol/L). Arterial urea extraction across the PDV and rumen increased from 2.7 to 5.4+/-0.5% and from 7.1 to 23.8+/-2.1% when cows were changed from high-N to low-N, respectively. Urea infusion did not decrease urea extractions, implying that urea transport rates were proportional to arterial urea concentrations. Urea extraction increased more across the rumen wall than across the total PDV for low-N compared with high-N, which implies that a larger proportion of total PDV uptake of arterial urea is directed toward the rumen with decreasing N intake. The ruminal vein - arterial (RA) concentration difference for ammonia increased instantly (first sampling 15 min after initiation of infusion) to the primed intravenous infusion when cows were adapted to the low-N diet. The RA difference for ammonia correlated poorly to the ventral ruminal concentration of ammonia (r=0.55). Relating the RA difference for ammonia to a function of both ruminal ammonia concentration and the RA difference for urea markedly improved the fit (r=0.85), indicating that a large

  18. Accuracy of the 14 C-urea breath test for the diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Gomes, Ana Thereza Britto; Secaf, Marie; Modena, Jose Luiz Pimenta; Troncon, Luiz Ernesto de Almeida; Oliveira, Ricardo Brandt de

    2002-01-01

    The development of simple, accurate and low-expense techniques for detection of Helicobacter pylori infection has great relevance. The objective was to determine the accuracy of a rapid 14 C-urea breath test (UBT) employing a very simple device for breathed air collection. One hundred and thirty-seven adult patients who underwent upper gastrointestinal endoscopy in the Clinical Hospital. The main measurements were histology for Helicobacter pylori (HP); urease test; urea breath test (UBT). One hundred and fifteen patients were infected by HP (HP +) according to both histology and the urease test, and 22 patients were HP-negative (HP-), according to the same two tests. UBT was capable of discriminating between HP + and HP- in a way that was similar to the combination of urease test and histology. When this combination of results is taken as the 'gold standard' for HP infection, the sensitivity and specificity of UBT are both greater than 90% for a range of cut-off points and breathed air collection times. It was concluded that the rapid UBT employing a simple device for air collection has a high accuracy in determining HP infection. (author)

  19. 1,1′-Binaphthyl-2,2′-dicarboxylic acid–urea (1/1

    Directory of Open Access Journals (Sweden)

    Edwin Weber

    2008-10-01

    Full Text Available In the title co-crystal, C22H14O4·CH4N2O, the 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA and urea molecules are connected via a system of hydrogen bonds into a chiral two-dimensional polymeric structure parallel to the (001 plane. As the crystal is centrosymmetric, it consists of alternately stacked BNDA–urea layers of opposite chirality. The urea H atoms trans to the C=O group are bonded in a chelating mode [R12(6] to the carbonyl O atom from one of the carboxylic acid groups which, in turn, acts as the donor of an O—H...O hydrogen bond to another urea molecule. The [010] chains thus formed are further connected via an R22(8 hydrogen-bond motif formed between urea and the second carboxylic acid group of BNDA.

  20. Melamine-bridged alkyl resorcinol modified urea - formaldehyde resin for bonding hardwood plywood

    Science.gov (United States)

    Chung-Yun Hse; Mitsuo Higuchi

    2010-01-01

    A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized...

  1. The Effect of Supplementation Urea and Sulfur in Mixed Cassava Waste Fermented and Soyabean Cake Waste on Digestibility of Protein and Blood Urea Male Sheep

    Directory of Open Access Journals (Sweden)

    M Bata

    1999-05-01

    Full Text Available Eighteen local male sheep were divided into 3 groups I,II and III based on the body weight 18.55±1.27, 15.79±0.67 and 13.14±1.33 kg respectively. Two level urea (2 and 3% and three levels Sulfur (0.02 and 0.3% as treatment, so pattern factorial 2x3 with Randomized Block Design used this experiment. All of the treatment get a same basal feed namely land-grass and concentrate with dry matter ratio 70:30.  The total intake of  dry matter was 4 % of body weight. The concentrate consist of cassava waste fermented  and soyabean cake waste with dry matter  ratio 77.50 : 22.50. Supplementation of urea and sulfur shown not significant interaction, but supplementation urea had effect high significantly (P<0.01 on digestibility of protein and sulfur only had effect significant  (P<0.05 on blood urea. These result had indication that enriched urea in the diet could increase protein digestibility and sulfur level 0.2% could prevent NH3 absorption from rumen. (Animal Production 1(2: 75-81 (1999   Key Words: cassava waste, soyabean cake waste, fermentation, digestibility, urea blood.

  2. Incorporating a hybrid urease-carbon nanotubes sensitive nanofilm on capacitive field-effect sensors for urea detection.

    Science.gov (United States)

    Siqueira, José R; Molinnus, Denise; Beging, Stefan; Schöning, Michael J

    2014-06-03

    The ideal combination among biomolecules and nanomaterials is the key for reaching biosensing units with high sensitivity. The challenge, however, is to find out a stable and sensitive film architecture that can be incorporated on the sensor's surface. In this paper, we report on the benefits of incorporating a layer-by-layer (LbL) nanofilm of polyamidoamine (PAMAM) dendrimer and carbon nanotubes (CNTs) on capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors for detecting urea. Three sensor arrangements were studied in order to investigate the adequate film architecture, involving the LbL film with the enzyme urease: (i) urease immobilized directly onto a bare EIS [EIS-urease] sensor; (ii) urease atop the LbL film over the EIS [EIS-(PAMAM/CNT)-urease] sensor; and (iii) urease sandwiched between the LbL film and another CNT layer [EIS-(PAMAM/CNT)-urease-CNT]. The surface morphology of all three urea-based EIS biosensors was investigated by atomic force microscopy (AFM), while the biosensing abilities were studied by means of capacitance-voltage (C/V) and dynamic constant-capacitance (ConCap) measureaments at urea concentrations ranging from 0.1 mM to 100 mM. The EIS-urease and EIS-(PAMAM/CNT)-urease sensors showed similar sensitivity (~18 mV/decade) and a nonregular signal behavior as the urea concentration increased. On the other hand, the EIS-(PAMAM/CNT)-urease-CNT sensor exhibited a superior output signal performance and higher sensitivity of about 33 mV/decade. The presence of the additional CNT layer was decisive to achieve a urea based EIS sensor with enhanced properties. Such sensitive architecture demonstrates that the incorporation of an adequate hybrid enzyme-nanofilm as sensing unit opens new prospects for biosensing applications using the field-effect sensor platform.

  3. Green urea synthesis catalyzed by hematite nanowires in magnetic field

    International Nuclear Information System (INIS)

    Yahya, Noorhana; Qureshi, Saima; Rehman, Zia ur; Alqasem, Bilal; Fai Kait, Chong

    2017-01-01

    The catalytic activity of hematite (α-Fe 2 O 3 ) nanowires under the influence of magnetic field on urea synthesis is considered green. The adsorption and subsequent dissociative reaction of hydrogen, nitrogen and carbon dioxide gases on the α-Fe 2 O 3 (111) nanowires were investigated using the density functional theory (DFT) method. The average adsorption energy is −4.12 kcal/mole at different sites. The adsorption of gases resulted in a difference in density and net spin of electrons from 68 to 120 and 0–21 respectively. In addition, it induces magnetic moment value of 36.33 µB, which confirms the enhanced magnetic behaviour of hematite. α-Fe 2 O 3 nanowires (NWs) synthesized by heating iron wire in a box furnace at (750−800) °C and as synthesized α-Fe 2 O 3 nanoparticles (NPs) were received to use as a catalyst in the magnetic reaction of urea synthesis. X-ray Diffractometer (XRD) confirms the peaks of rhombohedral structure of α-Fe 2 O 3 and Raman spectrum analyses confirms the α-Fe 2 O 3 peaks at 410 cm −1 , 500 cm −1 and 616 cm −1 . The needle-like shape of hematite nanowires with length ranging from 16–25) μm and diameter from 74 to 145 nm confirmed by Field emission scanning electron microscopy (FESEM). The magnetic properties of the nanowires exhibited different levels of saturation magnetization, for α-Fe 2 O 3 perpendicularly aligned direction (13.18 emu/g) and random direction (10.73 emu/g). Urea synthesis was done under magnetic field ranges from 0.0 to 2.5 T. The activation energy of α-Fe 2 O 3 NWs for urea production is lower than NPs in the range of 0–1 T, whereas it is reversed for higher magnetic induction values. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of urea at the peaks of 1690–1600 cm −1 . This green urea employing magnetically induced method could be a contender to the Haber-Bosch process currently used by the current industry which utilizes high temperature and high pressure

  4. Green urea synthesis catalyzed by hematite nanowires in magnetic field

    Science.gov (United States)

    Yahya, Noorhana; Qureshi, Saima; Rehman, Zia ur; Alqasem, Bilal; Fai Kait, Chong

    2017-04-01

    The catalytic activity of hematite (α-Fe2O3) nanowires under the influence of magnetic field on urea synthesis is considered green. The adsorption and subsequent dissociative reaction of hydrogen, nitrogen and carbon dioxide gases on the α-Fe2O3 (111) nanowires were investigated using the density functional theory (DFT) method. The average adsorption energy is -4.12 kcal/mole at different sites. The adsorption of gases resulted in a difference in density and net spin of electrons from 68 to 120 and 0-21 respectively. In addition, it induces magnetic moment value of 36.33 μB, which confirms the enhanced magnetic behaviour of hematite. α-Fe2O3 nanowires (NWs) synthesized by heating iron wire in a box furnace at (750-800) °C and as synthesized α-Fe2O3 nanoparticles (NPs) were received to use as a catalyst in the magnetic reaction of urea synthesis. X-ray Diffractometer (XRD) confirms the peaks of rhombohedral structure of α-Fe2O3 and Raman spectrum analyses confirms the α-Fe2O3 peaks at 410 cm-1, 500 cm-1 and 616 cm-1. The needle-like shape of hematite nanowires with length ranging from 16-25) μm and diameter from 74 to 145 nm confirmed by Field emission scanning electron microscopy (FESEM). The magnetic properties of the nanowires exhibited different levels of saturation magnetization, for α-Fe2O3 perpendicularly aligned direction (13.18 emu/g) and random direction (10.73 emu/g). Urea synthesis was done under magnetic field ranges from 0.0 to 2.5 T. The activation energy of α-Fe2O3 NWs for urea production is lower than NPs in the range of 0-1 T, whereas it is reversed for higher magnetic induction values. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of urea at the peaks of 1690-1600 cm-1. This green urea employing magnetically induced method could be a contender to the Haber-Bosch process currently used by the current industry which utilizes high temperature and high pressure.

  5. Multi site Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    International Nuclear Information System (INIS)

    Damian, P.A.G.; Sperl, J.I.; Janich, M.A.; Wiesinger, F.; Schulte, R.F.; Menzel, M.I.; Damian, P.A.G.; Damian, P.A.G.; Haase, A.; Janich, M.A.; Schwaiger, M.; Janich, M.A.; Khegai, O.; Glaser, S.J.

    2014-01-01

    Hyperpolarized 13 C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1- 13 C]pyruvate and downstream metabolites [1- 13 C]alanine, [1- 13 C]lactate, and [ 13 C] bicarbonate can be achieved through kinetic modeling. Since pyruvate interacts dynamically and simultaneously with its downstream metabolites, the purpose of this work is the determination of parameter values through a multi site, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multi site model to time-domain dynamic metabolite data. The results for different pyruvate doses were compared with those of different two-site models to evaluate the hypothesis that for identical data the uncertainty of a model and the signal-to-noise ratio determine the sensitivity in detecting small physiological differences in the target metabolism. In comparison to the two-site exchange models, the multi site model yielded metabolic conversion rates with smaller bias and smaller standard deviation, as demonstrated in simulations with different signal-to-noise ratio. Pyruvate dose effects observed previously were confirmed and quantified through metabolic conversion rate values. Parameter interdependency allowed an accurate quantification and can therefore be useful for monitoring metabolic activity in different tissues

  6. Hydration of urea and alkylated urea derivatives

    Science.gov (United States)

    Kaatze, Udo

    2018-01-01

    Compressibility data and broadband dielectric spectra of aqueous solutions of urea and some of its alkylated derivatives have been evaluated to yield their numbers Nh of hydration water molecules per molecule of solute. Nh values in a broad range of solute concentrations are discussed and are compared to hydration numbers of other relevant molecules and organic ions. Consistent with previous results, it is found that urea differs from other solutes in its unusually small hydration number, corresponding to just one third of the estimated number of nearest neighbor molecules. This remarkable hydration behavior is explained by the large density φH of hydrogen bonding abilities offered by the urea molecule. In terms of currently discussed models of reorientational motions and allied dynamics in water and related associating liquids, the large density φH causes a relaxation time close to that of undisturbed water with most parts of water encircling the solute. Therefore only a small part of disturbed ("hydration") water is left around each urea molecule. Adding alkyl groups to the basic molecule leads to Nh values which, within the series of n-alkylurea derivatives, progressively increase with the number of methyl groups per solute. With n-butylurea, Nh from dielectric spectra, in conformity with many other organic solutes, slightly exceeds the number of nearest neighbors. Compared to such Nh values, hydration numbers from compressibility data are substantially smaller, disclosing incorrect assumptions in the formula commonly used to interpret the experimental compressibilities. Similar to other series of organic solutes, effects of isomerization have been found with alkylated urea derivatives, indicating that factors other than the predominating density φH of hydrogen bond abilities contribute also to the hydration properties.

  7. Effect of urea on the photoactivity of titania powder prepared by sol-gel method

    International Nuclear Information System (INIS)

    Cheng Ping; Deng Changsheng; Gu Mingyuan; Dai Xiaming

    2008-01-01

    The synthesis of nanocrystalline titania powders from the hydrolysis of Ti(OBu n ) 4 in the presence of urea was investigated. DRS results showed that a redshift occurred in the absorption edge of titania with increasing the content of urea. XRD results indicated that urea showed a retarding effect on the transformation of titania from anatase to rutile. Moreover, the addition of urea resulted in a higher Brunauer-Emmett-Teller (BET) surface area as well as a larger average pore size of TiO 2 nanoparticles. The average pore size of urea/TiO 2 gels calcined at 500 deg. C increased with the increase of urea content, while the specific surface area increased with the amount of urea to reach a maximum at 10% and then decreased with further increase of the amount of urea. The maximal specific surface area of 64.4 m 2 g -1 was obtained for 10% urea/TiO 2 gels calcined at 500 deg. C, which showed an average particle size of 15 nm and pore size distribution in the range of mesopores centered at 5.8 nm. The photocatalytic experiments exhibited that titania nanoparticles prepared in the presence of urea could effectively photodegrade methyl orange under visible light irradiation due to the redshift of the absorption edge. The maximum photoactivity was achieved when the content of urea was 10%, which was attributed to the higher specific surface area

  8. Synthesis of [21-13C]-cholesterol

    International Nuclear Information System (INIS)

    Caballero, G.M.; Gros, E.G.

    1994-01-01

    The synthesis of [21- 13 C]-cholesterol from 3β-O-(t-butyldimethylsilyl)-17β-cyano-androst-5-ene is described. Labelled carbon-atom was introduced by Grignard reaction of nitrile derivative with [ 13 C]-methylmagnesium iodide. Location of label was confirmed by 13 C-NMR spectroscopy. (author)

  9. Effect of Coated Urea Fertilizer on Yield and Yield Components of Sweet Corn (KSC 403 under Deficit Irrigation

    Directory of Open Access Journals (Sweden)

    N Farid

    2017-11-01

    Full Text Available This study was carried out to assess the effect of coated urea fertilizer on yield and yield components of sweet corn (KSC 403 under different irrigation regimes, in Ramin Agriculture and Natural Sciences University, Iran by using strip split plot in a randomized complete block design with four replications. Three levels of deficit irrigation (100%, 80 and 60% of calculated water requirement of sweet corn were assigned as vertical factor and six sources of urea fertilizer (without urea, un-coated urea, sulfur-coated urea fertilizer, starch-coated urea, agar-coated urea and chitin-coated urea were assigned to horizontal factor. Effects of deficit water and source of fertilizer were statistically significant on plant height, 1000 kernel weight, ear diameter, and number of rows per ear, ear yield, biological yield and harvest index. Maximum of plant height (153.23 cm, 1000 kernel weight (104.51 g, grain yield (9853.3 kg/ha and biological yield (12471.6 kg/ha were obtained in chitin coated urea fertilizer. Maximum of ear diameter (4.67 cm and number of row per ear (13.22 were achieved in agar coated urea fertilizer and that of harvest index (45.79% was indicated by starch-coated urea. Maximum of length of ear, number of kernels per row and grain yield were 23.65cm, 25.83 and 7142 kg/ha, respectively, and were obtained with the using of chitin-coated urea fertilizer and 100% water requirement. Minimum values of these traits were 13.54 cm, 5.56 and 871 kg/ha, respectively, and were obtained by using of control (no urea application and 60% water requirement. Results showed that biopolymer coated urea is potent to improve some morphological characteristics and increase grain yield of sweet corn.

  10. Photoluminescence of urea- and urea/rhodamine B-capped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalo-Juan, I., E-mail: gonzalo@materials.tu-darmstadt.de; Macé, L.; Tengeler, S.; Mosallem, A.; Nicoloso, N.; Riedel, R.

    2016-07-01

    Urea- and rhodamine B (RhB)-capped TiO{sub 2} nanoparticles (NPs) have been prepared by solvothermal synthesis and characterized by HRTEM, XRD, FTIR, XPS, optical absorption and photoemission. The urea and urea/RhB ligands are capped to the surface of the TiO{sub 2} NPs for the first time through carbamate bonding. The band gap of TiO{sub 2} is slightly reduced from 3.1 eV to 3.0 eV in the urea capped TiO{sub 2} NPs (TU) and 2.9 eV for the NPs capped with urea/RhB (TUR). The generation of new trapping states in TU and TUR at the conduction band edges (surface oxygen vacancies) has been confirmed by the Urbach law providing tail state energies of 180 meV and 270 meV, respectively. These tail states are considered to be responsible for the strong reduction of the photoluminescence at ≈400 nm and the increased emission at ≈600 nm in TU and TUR. The findings suggest that urea- and RhB-capped TiO{sub 2} NPs could have potential applications as photocatalysts, opto-electronic devices, sensors, biological labels and anti-bacterial agents. - Highlights: • Urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles preparation. • Characterization of optical properties of urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles. • The recombination of electrons and holes is significantly reduced in the capped TiO{sub 2} nanoparticles, in comparison with TiO{sub 2}.

  11. Effects of urea foliar application and of ammonium sulphate and urea applied to the soil on yield and N utilization by beans (Phaseolus vulgaris L.)

    International Nuclear Information System (INIS)

    Muraoka, T.; Victoria, R.L.; Oliveira, J.P.; Boaretto, A.E.

    1984-01-01

    The effects of nitrogen applied to the soil (as ammonium sulphate and urea) and foliar application of urea supplementing or not the soil application, on bean yield and nitrogen utilization are studied in a cerrado soil. Labelled ammonium sulphate is applied at the rate of 20Kg N/ha at seeding or 15 or 25 days after seeding and 40 Kg N/ha at seeding or in two different applications. Labelled urea is applied at the rate of 20kg N/ha at seeding and 40 Kg N/ha splitted. Foliar application is done at 15,22, 29,36 and 45 days after seeding, with 2% urea solution labelled with 10% 15 N. (M.A.C.) [pt

  12. Variación de 13C en el ambiente de Madrid (atmósfera, aguas superficiales y aguas subterráneas

    Directory of Open Access Journals (Sweden)

    Redondo, R.

    1995-08-01

    Full Text Available Stable isotopes of carbon are studied in atmosphere, freshwater (rivers and groundwater of the region of Madrid. Sampling and analytical techniques are adapted for the isotopic study of carbon in the environment. The atmosphere samples show δ13C values from -13.92 to -15.67 ‰, closely related to the polution level of air. The water from wells, to the Tertiary detritic aquifer, with δ13C among -13.92 and -15.67 ‰. The dissolution of carbonatic rocks and the biologic activity could be the origin of the wide variations δ13C from -7.07 to -11.85 %0 found in the waters from rivers Jarama, Guadalix and Guadarrama.Se analizan el 13C de la atmósfera, ríos y pozos del área de Madrid, al objeto de evaluar su distribución y origen, mediante adaptación y desarrollo de técnicas de muestreo y análisis. Las muestras atmosféricas presentan valores de δ13C situados entre -9,81 y -14,64 ‰, que se corresponden gradualmente con los puntos de menor a mayor grado de polución por aportes principalmente de C02 procedente de la quema de combustibles fósiles. Las aguas de los pozos analizados, pertenecientes al acuífero terciario del detrítico, muestran un estrecho margen de variación, entre δ13C -13,92 y -15,67 ‰, relacionado con los procesos geoquímicos naturales. Las aguas de los ríos Jarama, Guadalix y Guadarrama, presentan una amplia variación en su composición isotópica (δ13C entre -7,07 y -11,85 ‰ debido a la disolución de carbonatos a su paso por las formaciones de calizas del Mesozoico y, en menor medida, a los aportes de efluentes contaminados.

  13. IRMS detection of testosterone manipulated with 13C labeled standards in human urine by removing the labeled 13C

    International Nuclear Information System (INIS)

    Wang, Jingzhu; Yang, Rui; Yang, Wenning; Liu, Xin; Xing, Yanyi; Xu, Youxuan

    2014-01-01

    Highlights: • 13 C labeled testosterone can be used to adjust the isotope ratio of testosterone. • The novel testosterone cannot be detected by the regular IRMS method in doping test. • A method was explored to remove the labeled 13 C. • The established method can be used to detect the manipulated testosterone. - Abstract: Isotope ratio mass spectrometry (IRMS) is applied to confirm testosterone (T) abuse by determining the carbon isotope ratios (δ 13 C value). However, 13 C labeled standards can be used to control the δ 13 C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the 13 C labeled atom at C-3 from the molecule of androsterone (Andro), the metabolite of T in urine, to produce the resultant (A-nor-5α-androstane-2,17-dione, ANAD). The difference in δ 13 C values between Andro and ANAD (Δδ 13 C Andro–ANAD , ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different 13 C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ 13 C Andro–ANAD post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ 13 C Andro–ANAD for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3- 13 C labeled standards

  14. Effects of bed-rest on urea and creatinine: correlation with changes in fat-free mass.

    Science.gov (United States)

    Bilancio, Giancarlo; Lombardi, Cinzia; Pisot, Rado; De Santo, Natale G; Cavallo, Pierpaolo; Cirillo, Massimo

    2014-01-01

    Bed-rest experiments are designed for investigation on catabolic effects of hypokinetic conditions and/or for microgravity simulation in on-ground aerospace research. Bed-rest effects include a reduction in fat-free mass and muscle mass. Urea and creatinine are catabolites of endogenous protein and of muscular energetic metabolism which are excreted mainly by the kidney. The study investigated on urea, creatinine, and kidney function during bed-rest. Twenty healthy young men underwent a 7-day adaptation period (day-6 to day-0) and a 35-day bed-rest experiment (day1 to day35) during normocaloric diet. Urine were collected from day-3 to day0 (baseline) and from day1 to day35. Blood samples and anthropometrical data were collected at day0 (baseline) and bed-rest days 7, 14, 21, 28, and 35. Bed-rest reduced plasma volume, weight, fat-free mass, and muscle mass (Pcreatinine, and no change in urinary creatinine. The overall integral of changes from day0 to day35 was on average +101.7 mg/dL for plasma urea (95%CI = +43.4/+159.9), +82.2 g/24 h for urinary urea (95%CI = +55.8/+108.7), -2.5 mg/dL for plasma creatinine (95%CI = -3.1/-1.9). Bed-rest reduced plasma cistatyn C also, which was used as mass-independent marker of glomerular filtration rate (-13.1%, P<0.05). Correlations with final reduction in fat-free mass and muscle mass were significant for the overall integral of changes in urinary urea from day0 to day35 (R = 0.706, P<0.001) and for early changes in urinary urea and plasma urea from day0 to day7 (R = 0.566, P = 0.009 and R = 0.715, P<0.001, respectively). Study results shows that urea is a marker of catabolic conditions secondary to hypokinetic conditions.

  15. Chemistry of the uranyl group. VI. Complexes of uranyl with hexamethylphosphoramide and urea

    Energy Technology Data Exchange (ETDEWEB)

    Zarli, B; Dall' olio, G; Sindellari, L [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

    1976-01-01

    Some uranyl complexes with hexamethylphosphoramide (HMPA) and urea were prepared and characterized. The compounds with the former ligand have the general formula UO/sub 2/X/sub 2/.HMPA (where X = (C/sub 2/H/sub 5/)/sub 2/NCSe/sub 2//sup -/, (C/sub 2/H/sub 5/)/sub 2/NCS/sub 2//sup -/ or CH/sub 3/COO/sup -/). For the acetato derivatives a dimeric acetato-bridged structure is suggested. Some properties of UO/sub 2/(NO/sub 3/)/sub 2/.2(HMPA) are also described. With the latter ligand, in addition to the complexes UO/sub 2/(NO/sub 3/)/sub 2/.2urea and (UO/sub 2/(urea)/sub 4/(H/sub 2/0))(NO/sub 3/)/sub 2/ already known, the novel complexes UO/sub 2/(pycrate)/sub 2/.4urea and (UO/sub 2/(CH/sub 3/COO)/sub 2/.urea)sub(n) (where n is probably 2) have been prepared. All attempts to obtain urea complexes of uranyl diethyldithio- or diethyldiselenocarbamate failed and only adducts of unsatisfactory stoichiometry were isolated.

  16. Urea recycling in ruminants

    International Nuclear Information System (INIS)

    Ohara, Yoshiaki; Niibayashi, Tsunekazu

    1980-01-01

    The transfer of blood urea into the alimentary tract of goats, as ruminants, was studied by the use of 15 N-urea, 15 N-ammonium chloride and physiological experimental techniques. Blood urea after an intravenous injection of 15 N-urea appeared in the first rumen via two routes, the saliva (approximately 60% of the serum urea concentration) and idrect diffusion from the wall of the first rumen, both as the ammonium-form N. The serum urea levels from diets containing different protein levels were paralleled with the protein levels, the ammonium level in the first rumen being similar to that of the serum urea. The transfer of low protein into the NH 3 pool of the first rumen was 56% of the total NH 3 in the entire alimentary tract, and the quantitative ratio of salivary secretion of diffusion in the first rumen was 1:9. The transfer of high protein was 14% in the entire alimentary tract, and the ratio of saliva to diffusion in the first rumen was 6:1. Thus, when protein uptake was large, salivary secretion was the primary route to the first rumen. Approximately 50% of the entire quantity of blood urea in the alimentary tract appeared in the first rumen, and 35%, in the lower alimentary tract, primarily in the duodenum and jejunum. (Chiba, N.)

  17. Urochloa ruziziensis responses to sources and doses of urea

    Directory of Open Access Journals (Sweden)

    João E. S. Lima

    2016-05-01

    Full Text Available ABSTRACT The use of products that promote reduction of nitrogen (N losses from the urea fertilizer can contribute to increasing its use efficiency in forage grasses. This study aimed to evaluate the effects of N sources and doses on the growth of Urochloa ruziziensis. The experiment was carried out in the growing season of 2007/2008 in Santo Antônio de Goiás-GO, in a Brazilian Oxisol. A completely randomized block was used, with four replicates in a factorial scheme, corresponding to two N sources (conventional urea and urea with urease inhibitor and five N doses (0, 50, 100, 200 and 300 kg ha-1, divided into equal applications in five periods (Nov 14 to Dec 13, Dec 14 to Jan 12, Jan 13 to Feb 11 - rainy season, Mar 24 to Apr 22 and Jul 10 to Aug 08 - dry season. The effects of the treatments were evaluated for: shoot dry matter, tiller density, total N content in the leaves and relative chlorophyll content. N fertilizer sources did not affect the evaluated variables; however, N fertilization allowed linear increases in all variables with higher values during the rainy period. The relative chlorophyll content in U. ruziziensis had positive correlation with its dry matter productivity.

  18. Whole-core analysis by 13C NMR

    International Nuclear Information System (INIS)

    Vinegar, H.J.; Tutunjian, P.N.; Edelstein, W.A.; Roemer, P.B.

    1991-01-01

    This paper reports on a whole-core nuclear magnetic resonance (NMR) system that was used to obtain natural abundance 13 C spectra. The system enables rapid, nondestructive measurements of bulk volume of movable oil, aliphatic/aromatic ratio, oil viscosity, and organic vs. carbonate carbon. 13 C NMR can be used in cores where the 1 H NMR spectrum is too broad to resolve oil and water resonances separately. A 5 1/4-in. 13 C/ 1 H NMR coil was installed on a General Electric (GE) CSI-2T NMR imager/spectrometer. With a 4-in.-OD whole core, good 13 C signal/noise ratio (SNR) is obtained within minutes, while 1 H spectra are obtained in seconds. NMR measurements have been made of the 13 C and 1 H density of crude oils with a wide range of API gravities. For light- and medium-gravity oils, the 13 C and 1 H signal per unit volume is constant within about 3.5%. For heavy crudes, the 13 C and 1 H density measured by NMR is reduced by the shortening of spin-spin relaxation time. 13 C and 1 H NMR spin-lattice relaxation times were measured on a suite of Cannon viscosity standards, crude oils (4 to 60 degrees API), and alkanes (C 5 through C 16 ) with viscosities at 77 degrees F ranging from 0.5 cp to 2.5 x 10 7 cp. The 13 C and 1 H relaxation times show a similar correlation with viscosity from which oil viscosity can be estimated accurately for viscosities up to 100 cp. The 13 C surface relaxation rate for oils on water-wet rocks is very low. Nonproton decoupled 13 C NMR is shown to be insensitive to kerogen; thus, 13 C NMR measures only the movable hydrocarbon content of the cores. In carbonates, the 13 C spectrum also contains a carbonate powder pattern useful in quantifying inorganic carbon and distinguishing organic from carbonate carbon

  19. KOMBINASI PENAMBAHAN UREA DAN EM-4 TERHADAP KUALITAS BOKASHI CAIR

    Directory of Open Access Journals (Sweden)

    Muhammad Dzulfikri Haidla

    2016-06-01

    Full Text Available The objectives of the study is to determine the effect of EM-4 and Urea addition on the liquid Bokashi quality of chicken manure. The field research was conducted at California Papaya Farm Pulau Sari, Pelaihari, and the nutrient levels of liquid Bokashi are then analyzed in the laboratory of PPLH Banjarbaru. The research was conducted from February to March 2015. It used Complete Randomized Design (CRD of factorial pattern 2 with three levels of treatment and three replications, the first factor is the addition of urea, consisting of three levels those are 0 g, 7.5 g, 15 g, the second factor is the addition of EM-4, consisting of three levels those are 0 ml, 25 ml, 50 ml, so that the number of trial units becomes 27 units. The variables measured are the Levels of Nitrogen (N, Phosphorous (P, Potassium (K, C-Organic, temperature, pH, color, smell, and texture. Quantitative observation data were analyzed using ANOVA and Duncan's Multiple Range Test (DMRT, while the qualitative observation data were analyzed using Kruskal-Wallis test. The results showed that the interaction between the addition of EM-4 and Urea were able to increase levels of nutrients N, P, K, C-Organic, and the temperature of the liquid Bokashi. Overall obtained treatment provision of EM-4 25 ml and 15 g Urea is the best treatment among other treatments. The addition of EM-4 was able to increase the levels of N, K, C-Organic and liquid Bokashi temperature, but it is unable to increase levels of the element P. Giving Urea can increase the levels of nutrients N, P, K, C-Organic, and the temperature of the liquid Bokashi. In observation of the organoleptic treatment with the addition of EM-4 and Urea, it tends to produce materials with better color, smell, and texture than the control treatment.

  20. Modeling of flux, binding and substitution of urea molecules in the urea transporter dvUT.

    Science.gov (United States)

    Zhang, Hai-Tian; Wang, Zhe; Yu, Tao; Sang, Jian-Ping; Zou, Xian-Wu; Zou, Xiaoqin

    2017-09-01

    Urea transporters (UTs) are transmembrane proteins that transport urea molecules across cell membranes and play a crucial role in urea excretion and water balance. Modeling the functional characteristics of UTs helps us understand how their structures accomplish the functions at the atomic level, and facilitates future therapeutic design targeting the UTs. This study was based on the crystal structure of Desulfovibrio vulgaris urea transporter (dvUT). To model the binding behavior of urea molecules in dvUT, we constructed a cooperative binding model. To model the substitution of urea by the urea analogue N,N'-dimethylurea (DMU) in dvUT, we calculated the occupation probability of DMU along the urea pore and the ratio of the occupation probabilities of DMU at the external (S ext ) and internal (S int ) binding sites, and we established the mutual substitution rule for binding and substitution of urea and DMU. Based on these calculations and modelings, together with the use of the Monte Carlo (MC) method, we further modeled the urea flux in dvUT, equilibrium urea binding to dvUT, and the substitution of urea by DMU in the dvUT. Our modeling results are in good agreement with the existing experimental functional data. Furthermore, the modelings have discovered the microscopic process and mechanisms of those functional characteristics. The methods and the results would help our future understanding of the underlying mechanisms of the diseases associated with impaired UT functions and rational drug design for the treatment of these diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Substitution of lucerne hay by untreated, urea-enriched and urea ...

    African Journals Online (AJOL)

    Wheat straw was left untreated (WS), enriched with 1.5% urea (UWS), or ammoniated with 5.5% urea in a stack for 8 .... nitrogen concentration for maximal microbial synthesis is in ... faeces and urine samples were taken daily and pooled for.

  2. Beneficios de la terapia con hidroxiúrea en niños con anemia de células falciformes = Benefits of hidroxyurea therapy in children with sickle cell disease

    Directory of Open Access Journals (Sweden)

    Donado Gómez, Jorge Hernando

    2012-04-01

    Full Text Available Objetivo: describir la toxicidad y los beneficios de la hidroxiúrea (HU en el tratamiento de niños con anemia de células falciformes (ACF.Materiales y métodos: estudio observacional descriptivo-retrospectivo de pacientes con ACF tratados con HU en el Hospital Pablo Tobón Uribe (HPTU de Medellín, Colombia, entre mayo de 2004 y septiembre de 2009. Se trató con este medicamento a 16 pacientes menores de 15 años, 11 de ellos (68,8% de sexo masculino. Todos los pacientes tenían anemia falciforme (Hb SS. Las variables se estudiaron antes y después del inicio de la HU. Resultados: se encontró una media de crisis dolorosas por ACF de 3,31 antes y 1,13 después de la HU (p = 0,006; la media de la necesidad de transfundir glóbulos rojos fue de 2,69 antes y 0,75 después (p = 0,112; los episodios de síndrome torácico agudo (STA tuvieron una media de 0,19 antes y 0,13 después (p = 0,705; la media de la necesidad de hospitalización por ACF fue de 1,94 antes y 1,06 después de la HU (p = 0,155. Un paciente (6,3% presentó toxicidad hematológica y dos (12,5% tuvieron toxicidad hepática, pero no hubo casos de toxicidad renal; tres pacientes (18,8% presentaron accidentes cerebrovasculares. No se encontraron neoplasias. Conclusión: la HU redujo significativamente la frecuencia de crisis dolorosas en los pacientes con ACF. La toxicidad fue en general aceptable. Se requieren estudios prospectivos, multicéntricos, doble ciego, controlados con placebo, para definir el papel de la HU en pacientes pediátricos.

  3. The elevated serum urea:creatinine ratio in canine babesiosis in South Africa is not of renal origin.

    Science.gov (United States)

    de Scally, M P; Leisewitz, A L; Lobetti, R G; Thompson, P N

    2006-12-01

    Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.

  4. Medium-term response of microbial community to rhizodeposits of white clover and ryegrass and tracing of active processes induced by 13C and 15N labelled exudates

    DEFF Research Database (Denmark)

    Kusliene, Gedrime; Rasmussen, Jim; Kuzyakov, Yakov

    2014-01-01

    and actinomycetes was unaffected by plant species, but pool of Gram-negative and Gram-positive bacteria was greater under white clover at the 10 percent significance level. In the short term, microorganisms more actively utilised fresh exudates (13C-labelled) of ryegrass than of white clover. We expected ryegrass...... microbial groups in soil under white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) following leaf-labelling with 13C-bicarbonate and 15N-urea. In this way microbial N and 15N and the composition of PLFAs reflect the medium-term (two months) response of microorganisms to rhizodeposits......, whereas the 13C-label of the PLFAs reflects the short-term (one week) utilisation of root exudates following labelling of shoots. In the medium term, microbial biomass N and 15N were greater under the ryegrass, whereas total PLFA was higher under white clover. The relative abundance of fungi...

  5. Passive water and urea permeability of a human Na(+)-glutamate cotransporter expressed in Xenopus oocytes

    DEFF Research Database (Denmark)

    Macaulay, Nanna; Gether, Ulrik; Klærke, Dan Arne

    2002-01-01

    to the K(0.5) value for glutamate activation of transport. The specific inhibitor DL-threo-beta-benzyloxyaspartate (TBOA) reduced the EAAT1-specific L(p) to 72 %. EAAT1 supported passive fluxes of [(14)C]urea and [(14)C]glycerol. The [(14)C]urea flux was increased in the presence of glutamate. The data...... suggest that the permeability depends on the conformational equilibrium of the EAAT1. At positive potentials and in the presence of Na(+) and glutamate, the pore is enlarged and water and urea penetrate more readily. The L(p) was larger when measured with urea or glycerol as osmolytes as compared...... with mannitol. Apparently, the properties of the pore are not uniform along its length. The outer section may accommodate urea and glycerol in an osmotically active form, giving rise to larger water fluxes. The physiological role of EAAT1 for water homeostasis in the central nervous system is discussed....

  6. con dietas suplementadas con Cromo-L-metionina

    Directory of Open Access Journals (Sweden)

    Ram\\u00F3n Garc\\u00EDa-Castillo

    2006-01-01

    Full Text Available Un total de 48 cerdos (Sus scrofa domesticus; 24 machos castrados y 24 hembras cruzados (Yorkshire, Hampshire, Duroc y Landrace de 3,5 a 4,0 meses de edad y 60,0 ± 5,0 kg PV en finalización. Se alimentaron con dietas isoproteícas (14,5 % PC e isoenergéticas (3.400 kcal EM/kg de MS, adicionadas con Cr-L-metionina (MiCroPlex® (0, 200, 400 y 600 ppb. El experimento tuvo una duración de 45 días y se realizó de agosto a noviembre del 2002 en las instalaciones de la Universidad Autónoma Agraria Antonio Narro, localizada en Saltillo, Coahuila, México. Al tener los animales aproximadamente 95 kg PV, se tomó muestra de 15 ml de sangre por cada animal para determinar la concentración de glucosa, ácido úrico, creatinina, urea, proteinas totales y colesterol. Se aplicó un diseño completamente al azar con arreglo factorial 2 x 4; dos para el factor sexo y cuatro para nivel de cromo. Los metabolitos en suero no fueron afectados (P>0,05 por el factor sexo. La glucosa en suero disminuyó (P<0,05 y el colesterol incrementó (P<0,05 con cromo en la dieta. Se concluye que el Cr incrementa el metabolismo de glucosa y disminuye el de colesterol, con lo cual puede haber energía disponible para síntesis de proteína la cual es necesaria para el crecimiento de los animales

  7. Análisis Molecular de las Mutaciones 2299delG y C759F en Individuos Colombianos con Retinitis Pigmentosa e Hipoacusia Neurosensorial

    OpenAIRE

    López, Greizy; Gelvez, Nancy Yaneth; Urrego, Luisa Fernanda; Florez, Silvia; Medina, David; Rodríguez, Vicente; Tamayo, Marta Lucía

    2014-01-01

    Objetivo: Determinar la presencia de las mutaciones 2299delG y C759F en 37 individuos colombianos no relacionados con asociación de RP e hipoacusia neurosensorial. Materiales y métodos: análisis de secuencia directa del exón 13 del gen USH2A en todos los individuos seleccionados para el estudio. Resultados: la mutación 2299delG fue observada únicamente en individuos con Síndrome de Usher tipo II, mientras que la mutación C759F, no fue observada en ninguno de los individuos del estudio. Obj...

  8. Hydrogen bonding of formamide, urea, urea monoxide and their thio

    Indian Academy of Sciences (India)

    Ab initio and DFT methods have been employed to study the hydrogen bonding ability of formamide, urea, urea monoxide, thioformamide, thiourea and thiourea monoxide with one water molecule and the homodimers of the selected molecules. The stabilization energies associated with themonohydrated adducts and ...

  9. IRMS detection of testosterone manipulated with 13C labeled standards in human urine by removing the labeled 13C.

    Science.gov (United States)

    Wang, Jingzhu; Yang, Rui; Yang, Wenning; Liu, Xin; Xing, Yanyi; Xu, Youxuan

    2014-12-10

    Isotope ratio mass spectrometry (IRMS) is applied to confirm testosterone (T) abuse by determining the carbon isotope ratios (δ(13)C value). However, (13)C labeled standards can be used to control the δ(13)C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the (13)C labeled atom at C-3 from the molecule of androsterone (Andro), the metabolite of T in urine, to produce the resultant (A-nor-5α-androstane-2,17-dione, ANAD). The difference in δ(13)C values between Andro and ANAD (Δδ(13)CAndro-ANAD, ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different (13)C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ(13)CAndro-ANAD post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ(13)CAndro-ANAD for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3-(13)C labeled standards. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Green urea synthesis catalyzed by hematite nanowires in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Noorhana, E-mail: noorhana_yahya@petronas.com.my; Qureshi, Saima; Rehman, Zia ur; Alqasem, Bilal; Fai Kait, Chong

    2017-04-15

    The catalytic activity of hematite (α-Fe{sub 2}O{sub 3}) nanowires under the influence of magnetic field on urea synthesis is considered green. The adsorption and subsequent dissociative reaction of hydrogen, nitrogen and carbon dioxide gases on the α-Fe{sub 2}O{sub 3} (111) nanowires were investigated using the density functional theory (DFT) method. The average adsorption energy is −4.12 kcal/mole at different sites. The adsorption of gases resulted in a difference in density and net spin of electrons from 68 to 120 and 0–21 respectively. In addition, it induces magnetic moment value of 36.33 µB, which confirms the enhanced magnetic behaviour of hematite. α-Fe{sub 2}O{sub 3} nanowires (NWs) synthesized by heating iron wire in a box furnace at (750−800) °C and as synthesized α-Fe{sub 2}O{sub 3} nanoparticles (NPs) were received to use as a catalyst in the magnetic reaction of urea synthesis. X-ray Diffractometer (XRD) confirms the peaks of rhombohedral structure of α-Fe{sub 2}O{sub 3} and Raman spectrum analyses confirms the α-Fe{sub 2}O{sub 3} peaks at 410 cm{sup −1}, 500 cm{sup −1} and 616 cm{sup −1}. The needle-like shape of hematite nanowires with length ranging from 16–25) μm and diameter from 74 to 145 nm confirmed by Field emission scanning electron microscopy (FESEM). The magnetic properties of the nanowires exhibited different levels of saturation magnetization, for α-Fe{sub 2}O{sub 3} perpendicularly aligned direction (13.18 emu/g) and random direction (10.73 emu/g). Urea synthesis was done under magnetic field ranges from 0.0 to 2.5 T. The activation energy of α-Fe{sub 2}O{sub 3} NWs for urea production is lower than NPs in the range of 0–1 T, whereas it is reversed for higher magnetic induction values. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of urea at the peaks of 1690–1600 cm{sup −1}. This green urea employing magnetically induced method could be a contender to the Haber-Bosch process

  11. The /sup 13/C-/sup 13/C spin-spin coupling constants and the conformational equilibrium of alkyl phenyl sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Krividin, L.B.; Kalabin, G.A.

    1985-08-10

    The authors measure the direct geminal and vicinal spinspin coupling constants between the C-13 nuclei of the phenyl group in the series of alkyl phenyl sulfides C/sub 6/H/sub 5/SR. It was shown that the variation in most of the discussed constants is determined by the ratio of the planar and orthogonal conformers. Linear relationships were obtained between the C-13-C-13 constants and the fractions of the planar conformer. The C-13-C-13 spin-spin coupling constants in the planar and orthogonal conformers of the compounds were calculated by means of empirical relationships.

  12. Electric dipole moment of 13C

    Science.gov (United States)

    Yamanaka, Nodoka; Yamada, Taiichi; Hiyama, Emiko; Funaki, Yasuro

    2017-06-01

    We calculate for the first time the electric dipole moment (EDM) of 13C generated by the isovector charge conjugation-parity (CP)-odd pion exchange nuclear force in the α -cluster model, which describes well the structures of low-lying states of the 13C nucleus. The linear dependence of the EDM of 13C on the neutron EDM and the isovector CP-odd nuclear coupling is found to be d13C=-0.33 dn-0.0020 G¯π(1 ) . The linear enhancement factor of the CP-odd nuclear coupling is smaller than that of the deuteron, due to the difference of the structure between the 1 /21- state and the opposite-parity (1 /2+ ) states. We clarify the role of the structure played in the enhancement of the EDM. This result provides good guiding principles to search for other nuclei with large enhancement factor. We also mention the role of the EDM of 13C in determining the new physics beyond the standard model.

  13. Characterization of methacetin-methoxy-"1"3C

    International Nuclear Information System (INIS)

    Lu Weijing; Lu Hao; Yang Weicheng; Liu Weixia; Li Shuai; Xu Zhongjie; Guan Liang; Zhu Chengmo; Chen Suyun; Jiang Lei

    2010-01-01

    Methacetin-methoxy-"1"3C was synthesized by using methanol-"1"3C with a novel method, and the characterization of it was performed using HPLC, LC-MS and "1HMNR. The results indicated that the synthetic was right. And the yield of methacetin-methoxy-"1"3C was 70.0% with 99% "1"3C abundance and 99.8% purity. Compared with the classical method, there was more benefit. The methacetin "1"3C-breath test was performed with the synthetic on the live mice, which showed a precise reflection of alteration of liver function in liver injury and functional recovery. (authors)

  14. Distribution and excretion of. cap alpha. -naphthylthio-(/sup 14/C)urea in Albino rats

    Energy Technology Data Exchange (ETDEWEB)

    Patil, T N; Radhakrishnamurty, R [Central Food Technological Research Inst., Mysore (India)

    1977-09-01

    ..cap alpha..-naphthylthio-(/sup 14/C) urea was synthesised by allowing potassium (/sup 14/C)thiocyanate to react with ..cap alpha..-naphthylamine. Its distribution and excretion were studied in Albino rats following the administration of this rodenticide. Considerable radioactivity observed in liver and kidney, increased till 8 hr and later decreased. About 80% of the activities present in serum and pleural effusion were found in the respective albumin fractions. Approximately 40% of the dose administered was excreted in urine and less than 1% in faeces in 20 hr. About 36% of the total urinary activity was recovered as unchanged compound and the rest was distributed in three metabolites with low Rsyb(f) values. Decrease in cytochsome P-450 content and activities of N, N-dimethylaniline demethylase, aryl 4-hydroxylase and reduced NAD dehydrogenase were observed in ..cap alpha..-naphthylathiourea-treated rats.

  15. 13C/12C ratios in human urine concrementes

    International Nuclear Information System (INIS)

    Hoefs, J.; Armbruster, T.

    1978-01-01

    Oxalate, uric acid, and phosphate stones have been analyzed for their carbon isotope composition. The oxalate stones show delta 13 C values between -17.0 and -19.5 pro mille, the uric acid stones between -14.9 and -19.4 pro mille, and the phosphate stones between -13.0 and -23.9 pro mille. It is proposed that endogenic rather than exogenic sources are responsible for the 13 C/ 12 C ratios of the stones. The isotopic composition of the phosphate stones seems to be influenced primarily by bacterial activity. (orig.) [de

  16. Silicone Doped Chitosan-Acrylamide Coencapsulated Urea Fertilizer: An Approach to Controlled Release Fertilizers

    Directory of Open Access Journals (Sweden)

    Sempeho Ibahati Siafu

    2017-01-01

    Full Text Available In the absence of special management practices, urea is known to undergo chemical transformations resulting in severe losses (≈60–70% of total fertilizer applied. In an attempt to design urea controlled release fertilizers in order to counterbalance the 60–70% loss, urea was cross-linked with chitosan and acrylamide under refluxed in situ copolymerization technique; the procedures were repeated with silicone doping prior cross-linking with MBA. The particles were characterized with FTIR/ATR, EDX, XRD, and SEM. The IR bands observed within 3426–409 cm−1 revealed the formation of new bands after coencapsulation for the νγN-H, νβN-H, νOH, νsNH2, νCH2, νC=O, δ′NH2, νC=C, δNH2, νC-N, βCH3, $C-N, γNH2, νC=O, and $CH2. Crystallinity indices for urea with and without silicone doping were found to be 50.9% and 72.1%, respectively, with a distinctive split peak at (d 12.30°. The formation of Microdunes and Microballs 3D network sized 0.64 μm was noted. Release profiles demonstrated that 80% N was released in a period of 30 days at RT and pH 7. The release patterns exhibited linear and deformed sigmoid release models. Empirically, the findings demonstrated that it is possible to design urea controlled release fertilizers with varying particle sizes and morphologies by using chitosan-acrylamide coencapsulation.

  17. Stereoselective synthesis of L-[4-13C]carnitine

    International Nuclear Information System (INIS)

    Unkefer, C.J.; Ehler, D.S.

    1991-01-01

    The stereoselective synthesis of L-[4- 13 C]carnitine was achieved in 5 steps. The label was introduced from K 13 CN into an easily separated diastereomeric pair of 3-deoxy-D-[1- 13 C]aldohexoses. Reductive amination of the labeled aldohexose yielded the corresponding D-1-(dimethylamino)[1- 13 C]alditol which was oxidized in two steps and alkylated with iodomethane to yield L-[4- 13 C]carnitine. The stereochemical integrity at C-2 of the 3-deoxy-D-[1- 13 C]glucose precursor was maintained throughout the synthesis of L-[4- 13 C]carnitine. (author)

  18. Cinética de fermentación y degradabilidad ruminal in vitro de dietas con diferente fuente de nitrógeno

    Directory of Open Access Journals (Sweden)

    Carlos Aguirre Valverde

    2017-12-01

    Full Text Available El objetivo de este trabajo fue determinar la cinética de fermentación y degradabilidad ruminal in vitro de dietas con diferente fuente de nitrógeno para alimentación de rumiantes. Se formularon tres dietas (D con diferentes fuentes de nitrógeno D1 (harina de pescado, D2 (pasta de soya y D3 (urea, estas fueron iso-calóricas con 2900 kilocalorías de energía digestible en materia seca (kcal ED/MS e iso-proteícas 13% proteína bruta (PB. Los periodos de incubación utilizados fueron 0, 2, 4, 8, 12, 24, 48 y 72 horas. En la evolución del Ph en la cinética ruminal de las tres dietas con diferentes fuentes de nitrógenos, se puede determinar que la D3 y D1 registraron el mayor pH (P

  19. Relationship between plasma uridine and urinary urea excretion.

    Science.gov (United States)

    Ka, Tuneyoshi; Inokuchi, Taku; Tamada, Daisuke; Suda, Michio; Tsutsumi, Zenta; Okuda, Chihiro; Yamamoto, Asako; Takahashi, Sumio; Moriwaki, Yuji; Yamamoto, Tetsuya

    2010-03-01

    To investigate whether the concentration of uridine in plasma is related to the urinary excretion of urea, 45 healthy male subjects with normouricemia and normal blood pressure were studied after providing informed consent. Immediately after collection of 24-hour urine, blood samples were drawn after an overnight fast except for water. The contents of ingested foods during the 24-hour urine collection period were described by the subjects and analyzed by a dietician. Simple regression analysis showed that plasma uridine was correlated with the urinary excretions of urea (R = 0.41, P urea. These results suggest that an increase in de novo pyrimidine synthesis leads to an increased concentration of uridine in plasma via nitrogen catabolism in healthy subjects with normouricemia and normal blood pressure. (c) 2010 Elsevier Inc. All rights reserved.

  20. Características clínico-epidemiológicas de pacientes con cólera en la ciudad de México

    Directory of Open Access Journals (Sweden)

    Vilchis-Guizar Agustina Elena

    1999-01-01

    Full Text Available OBJETIVO: Comparar las características clínico-epidemiológicas de enfermos de cólera (casos con las de pacientes con diarrea por otra causa (no casos, atendidos en las unidades médicas de la Delegación 2 Noreste del Distrito Federal, del Instituto Mexicano del Seguro Social (IMSS. MATERIAL Y MÉTODOS: Se realizó un estudio transversal analítico y se utilizaron datos de 4 952 notificaciones reunidas entre 1995 y 1998 a través del formato oficial "Hoja de notificación inmediata de casos de cólera", que cada unidad médica envía a la Coordinación de Salud Comunitaria del IMSS. Mediante estadística analítica se compararon medias y proporciones para ambos grupos. RESULTADOS: Se identificaron 588 pacientes con cólera y 4 364 con diarrea por otra causa. En el primer grupo, la edad promedio varió entre los 39 y los 51 años, y predominó el sexo femenino (54%. Durante 1995 y 1997 (años en los que se presentó un número más elevado de casos, los pacientes de cólera, en relación con el grupo de comparación, presentaron una mayor frecuencia de evacuaciones líquidas (97 vs. 73%, con aspecto de "agua de arroz" (31 vs. 13%, vómitos (72 vs. 63%, espasmos musculares (49 vs. 26%, deshidratación (83 vs. 71%, choque hipovolémico (10 vs. 1% y defunciones (0.85% vs. 0.25%, con diferencias estadísticamente significativas. CONCLUSIONES: El cólera muestra un comportamiento cíclico bianual; a mayor frecuencia mayor gravedad de la enfermedad. Se requiere incrementar la vigilancia epidemiológica y el esfuerzo médico para un diagnóstico y tratamiento oportuno.

  1. 1-(o-Tol­yl)thio­urea

    Science.gov (United States)

    Corrêa, Rodrigo S.; Ribeiro, Leandro; Ellena, Javier; Estévez-Hernández, Osvaldo; Duque, Julio

    2008-01-01

    In the title compound, C8H10N2S, the o-tolyl group and the thio­urea core are planar. The mean planes of the two groups are almost perpendicular [82.19 (8)°]. The thio­urea group is in the thio­amide form, in which resonance is present. In the crystal structure, mol­ecules are linked by inter­molecular N—H⋯S hydrogen bonds, forming two infinite chains parallel to the (110) and (10) planes. PMID:21201662

  2. Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

    KAUST Repository

    Lee, Junggil; Kim, Youngdeuk; Kim, Wooseung

    2012-01-01

    to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C

  3. Regeneración endodóntica con células madre

    Directory of Open Access Journals (Sweden)

    Elizabeth Santiago Dager

    2014-12-01

    Full Text Available Los procedimientos de regeneración del complejo pulpar están dirigidos a controlar la infección con un mínimo de instrumentos y abundante irrigación, para lo cual se han propuesto varios protocolos con ligeras variantes, sin consenso entre los autores; en el presente artículo se describen y analizan los 3 principales, con especial énfasis en los aspectos menos esclarecidos de un tratamiento fascinante con células madre en la rama de la endodoncia y cuyos avances proporcionan beneficios inestimables a los pacientes en quienes se aplica

  4. Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows.

    Science.gov (United States)

    Spek, J W; Dijkstra, J; Bannink, A

    2016-05-01

    The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed to obtain insight in urea transfer characteristics within the mammary gland and from the mammary gland to blood plasma in dairy cows at various concentrations of plasma urea nitrogen (PUN; mg of N/dL) and MUN. Urea transfer from milk to blood plasma and urea transfer within the mammary gland itself was evaluated in a 4×4 Latin square design using 4 lactating multiparous Holstein-Friesian cows (milk production of 39.8±4.70kg/d and 90±3.9 d in milk). Treatments consisted of 4 primed continuous intravenous urea infusions of 0, 5, 10, and 15g of urea/h. Boluses of [(15)N(15)N]urea were injected in cistern milk at 20, 60, and 100 min before the 1700h milking. Milk was collected in portions of approximately 2 L at the 1700h milking. Milk samples were analyzed for urea and enrichment of (15)N-urea. Results from one cow were discarded because of leakage of milk from the teats after injection of boluses of [(15)N(15)N]urea. Increasing urea infusion rate linearly increased PUN from 11.4 (0g of urea/h) to 25.9mg/dL (15g of urea/h) and MUN from 10.3 (0g of urea/h) to 23.5 (15g of urea/h) mg of N/dL. The percentage of injected [(15)N(15)N]urea recovered from milk at the time of injection was not affected by urea infusion rate and varied between 65.1 and 73.0%, indicating that a substantial portion of injected [(15)N(15)N]urea was not accounted for by collected milk. The estimated fractional disappearance rate of (15)N-urea from milk to blood (Kurea; per hour) linearly increased from 0.429 (0g of urea/h) to 0.641 per hour (15g of urea/h). Cistern injected [(15)N(15)N]urea diffused within 20 min after injection toward alveoli milk. Calculations with the average Kurea estimated in this

  5. In vivo urea cycle flux distinguishes and correlates with phenotypic severity in disorders of the urea cycle

    Science.gov (United States)

    Lee, Brendan; Yu, Hong; Jahoor, Farook; O'Brien, William; Beaudet, Arthur L.; Reeds, Peter

    2000-01-01

    Urea cycle disorders are a group of inborn errors of hepatic metabolism that result in often life-threatening hyperammonemia and hyperglutaminemia. Clinical and laboratory diagnosis of partial deficiencies during asymptomatic periods is difficult, and correlation of phenotypic severity with either genotype and/or in vitro enzyme activity is often imprecise. We hypothesized that stable isotopically determined in vivo rates of total body urea synthesis and urea cycle-specific nitrogen flux would correlate with both phenotypic severity and carrier status in patients with a variety of different enzymatic deficiencies of the urea cycle. We studied control subjects, patients, and their relatives with different enzymatic deficiencies affecting the urea cycle while consuming a low protein diet. On a separate occasion the subjects either received a higher protein intake or were treated with an alternative route medication sodium phenylacetate/benzoate (Ucephan), or oral arginine supplementation. Total urea synthesis from all nitrogen sources was determined from [18O]urea labeling, and the utilization of peripheral nitrogen was estimated from the relative isotopic enrichments of [15N]urea and [15N]glutamine during i.v. co-infusions of [5-(amide)15N]glutamine and [18O]urea. The ratio of the isotopic enrichments of 15N-urea/15N-glutamine distinguished normal control subjects (ratio = 0.42 ± 0.06) from urea cycle patients with late (0.17 ± 0.03) and neonatal (0.003 ± 0.007) presentations irrespective of enzymatic deficiency. This index of urea cycle activity also distinguished asymptomatic heterozygous carriers of argininosuccinate synthetase deficiency (0.22 ± 0.03), argininosuccinate lyase deficiency (0.35 ± 0.11), and partial ornithine transcarbamylase deficiency (0.26 ± 0.06) from normal controls. Administration of Ucephan lowered, and arginine increased, urea synthesis to the degree predicted from their respective rates of metabolism. The 15N-urea/15N-glutamine ratio

  6. Improved compatibility between polystyrene and poly(vinylidene fluoride) by the addition of urea

    International Nuclear Information System (INIS)

    Melad, O.; Teim, O.A.; Sobeh, E.

    2005-01-01

    The viscosity behavior of dilute urea solution of dimethylformamide (Dmf) of Polystyrene-Poly(vinylidene fluoride) has been studied at 25 degree C. The results show that the polymer mixtures are incompatible in DMF solution in the absence of urea. The influence of urea addition on the degree of compatibility of the polymer mixture has been studied in terms of the compatibility parameters (A6/M, kbm , A [77] ,a and /?) respectively

  7. Determing the fate of selected antibiotics during nitrogen recovery via urea-formaldehdye synthesis

    OpenAIRE

    Kashobwe, Lackson

    2016-01-01

    The work presented here focused on the determination of fate of four selected antibiot-ics: enrofloaxicin, oxytetracyline, sulfamethoxazole and tylosin during nitrogen recovery from source separated urine via urea formaldehyde synthesis. The experimental pH was at 2 and temperature at 25°C throughout the chemical reaction, preventing urea hydroly-sis. Five main chemical reactions: aqueous + antibiotics, Urine + formaldehyde + antibi-otics (UF synthesis experiment), urea-formaldehyde polymer +...

  8. /sup 13/C-/sup 13/C spin-spin coupling constants in structural investigations. II. Conformational structure of vinyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Krivdin, L.B.; Shcherbakov, V.V.; Bzhezovskii, V.M.; Kalabin, G.A.

    1986-10-10

    The /sup 13/C-/sup 13/C spin-spin coupling constants between the carbon nuclei of the vinyl group were measured for a series of vinyl ethers. It was established that the unshared electron pairs of the oxygen atom can make a substantial stereospecific contribution to the direct /sup 13/C-/sup 13/C constants of the adjacent nuclei. The observed effect was used to establish the conformational structure of the compounds.

  9. Fractionation of hydrogen and oxygen isotopes between hydrated and free water molecules in aqueous urea solution

    International Nuclear Information System (INIS)

    Kakiuchi, M.; Matsuo, S.

    1985-01-01

    Ratios of D/H and 18 O/ 16 O in the vapor phase in equilibrium with aqueous urea solution with different urea molalities were measured at 15 and 25 0 C. Under the assumption that urea solutions consist of two species, i.e., the urea-water cluster and free water, the results are interpreted to give the average hydration number, i.e., the number of water molecules per urea molecule in the urea-water cluster. Good agreement was obtained for the hydration number estimated independently from hydrogen and oxygen isotopic fractions. On the basis of hydrogen isotopic data at 25 0 C, the average hydration number of urea in the cluster is 6.3 +/- 0.8 at 2.1 m and 2.75 +/- 0.08 at saturation (20.15 m). The corresponding average hydration numbers based on oxygen isotopic data were calculated to be 6.7 +/- 2.4 at 2.1 m and 2.75 +/- 0.25 at urea saturation. HD 16 O is enriched in the urea-water cluster and H 2 18 O is enriched in free water. Isotopic partitioning between the cluster and free water is markedly different from those between hydration spheres and free water in aqueous electrolyte solutions. 29 references, 6 figures, 5 tables

  10. [13C] GC-C-IRMS analysis of methylboronic acid derivatives of glucose from liver glycogen after the ingestion of [13C] labeled tracers in rats.

    Science.gov (United States)

    Luengo, Catherine; Azzout-Marniche, Dalila; Fromentin, Claire; Piedcoq, Julien; Lemosquet, Sophie; Tomé, Daniel; Gaudichon, Claire

    2009-11-01

    We developed a complete method to measure low [(13)C] enrichments in glycogen. Fourteen rats were fed a control diet. Six of them also ingested either [U-(13)C] glucose (n=2) or a mixture of 20 [U-(13)C] amino acids (n=4). Hepatic glycogen was extracted, digested to glucose and purified on anion-cation exchange resins. After the optimization of methylboronic acid derivatization using GC-MS, [(13)C] enrichment of extracted glucose was measured by GC-C-IRMS. The accuracy was addressed by measuring the enrichment excess of a calibration curve, which observed values were in good agreement with the expected values (R=0.9979). Corrected delta values were -15.6+/-1.6 delta(13)C (per thousand) for control rats (n=8) and increased to -5 to 8 delta(13)C (per thousand) per thousand and 12-14 delta(13)C (per thousand) per thousand after the ingestion of [U-(13)C] amino acids or [U-(13)C] glucose as oral tracers, respectively. The method enabled the determination of dietary substrate transfer into glycogen. The sequestration of dietary glucose in liver glycogen 4 h after the meal was 35% of the ingested dose whereas the transfer of carbon skeletons from amino acids was only 0.25 to 1%.

  11. Inestabilidad de microsatélites en pacientes con diagnóstico de cáncer colorrectal

    OpenAIRE

    Ortiz, César; Dongo-Pflucker, Kenny; Martín-Cruz, Luis; Barletta Carrillo, Claudia; Mora-Alferez, Pamela; Arias, Abelardo

    2016-01-01

    Objetivo: Determinar la presencia de inestabilidad de microsatélites en pacientes con cáncer colorrectal usando el panel molecular Bethesda y discutir su importancia en pacientes con sospecha de cáncer colorrectal hereditario no polipósico (HNPCC) o con sospecha de síndrome de Lynch. Materiales y métodos: Se trabajó con muestras de sangre periférica y tejido tumoral de 28 pacientes con diagnóstico de cáncer colorrectal remitidos al laboratorio de Biología Molecular del Instituto Nacional de E...

  12. Synthesis of [1-.sup.13C]pyruvic acid], [2-.sup.13C]pyruvic acid], [3-.sup.13C]pyruvic acid] and combinations thereof

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Rodolfo A. (Santa Fe, NM), Unkefer; Clifford J. (Los Alamos, NM), Alvarez; Marc, A [Santa Fe, NM

    2012-06-12

    The present invention is directed to the labeled compounds, ##STR00001## wherein C* is each either .sup.13C and .sup.12C where at least one C* is .sup.13C, each hydrogen of the methylene group is hydrogen or deuterium, the methyl group includes either zero or three deuterium atoms, Q is sulfide, sulfinyl, or sulfone, Z is an aryl group such as 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, or a phenyl group ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently either hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group such as NH.sub.2, NHR and NRR' where R and R' are each independently either a C.sub.1-C.sub.4 lower alkyl, a phenyl, and an alkoxy group, and the methyl group can include either zero or three deuterium atoms. The present invention is also directed to the labeled compounds ##STR00003##

  13. Investigation of the association between glaucoma and Helicobacter pylori infection using the 14C-urea breath test

    International Nuclear Information System (INIS)

    Tuzcu, Esra Ayhan; Aydogan, Fusun; Motor, Vicdan Koksaldi; Ilhan, Ozgur; Daglioglu, Mutlu Cihan; Coskun, Mesut; Parlakfikirer, Nihan; Keskin, Ugurcan

    2015-01-01

    Purpose: to investigate the association between glaucoma and Helicobacter pylori infection by evaluating for the presence of H. pylori infection in patients with glaucoma using the 14C-urea breath test (14C-UBT). Methods: Using 14C-UBT, H. pylori infection positivity was compared between a group of patients with primary open-angle glaucoma and a control group with normal intraocular pressure and a normal optic disc or normal perimetry. Results: the 14C-UBT was positive in 18 (51.42%) out of 35 patients in the glaucoma group and in 15 (42.85%) out of 35 patients in the control group. H. pylori infection positivity rates were similar between the glaucoma and control groups (p>0.05). Conclusion: according to the 14C-UBT, there is no association between primary open-angle glaucoma and H. pylori infection. (author)

  14. Effect of urea treatment on digestibility and utilization of sorghum straw

    Directory of Open Access Journals (Sweden)

    Nianogo A.J.

    1999-01-01

    Full Text Available Nine male goats and nine castrated lambs were randomly divided into three groups of six animals to receive one of three experimental diets in a digestion trial. Diet S, provided chopped sorghum straw (SS, 28/ concentrate (C and 10/ Dolichos lablab hay (D. Diet Su1 provided SS containing 2/ urea, 24/ C and 12/ D, and diet Sue1 provided SS treated to contain 2/ urea and ensiled for 28 days, plus 25/ C and 14/ D. Twenty four lambs were randomly divided into three groups of eight animals to receive one of three diets in a 56-day growth trial; diet S2 provided SS plus 60/ C; diet Su2 provided SS containing 2/ urea plus 60/ C, and diet Sue2 provided SS treated to contain 2/ urea and ensiled for 28 days, plus 60/ C. The digestion trial showed higher (P<.05 daily intake of dry matter, organic matter, crude protein and neutral detergent fiber for S, than for Sue1 and Su1. Dry matter intake was 55.93; 39.42 and 42.34 g[kgE0.75E-1 for S1, Su1 and Sue1, respectively. Dry matter intake was slightly higher for lambs [50 g[kgE0.75E-1] than for goats [42 g[kE0.75E-1]. There was no effect of dietary treatments on apparent nutrient digestibility. During the growth trial, intake of straw varied from 17.97 (S2 to 24.78 g[kgE0.75E-1 (Sue2, but differences were not significant. Daily gain did not differ between treatments. Total feed intake and feed efficiency were only slightly affected by dietary treatments. Average feed intake was 4.36/ of body weight. High concentrate intakes may have upset the effect of urea treatment and silo fermentation in this study.

  15. Con Edison power failure of July 13 and 14, 1977. Final staff report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    On July 13, 1977 the entire electric load of the Con Edison system was lost, plunging New York City and Westchester County into darkness. The collapse resulted from a combination of natural events, equipment malfunctions, questionable system-design features, and operating errors. An attempt is made in this report to answer the following: what were the specific causes of the failure; if equipment malfunctions and operator errors contributed, could they have been prevented; to what extent was Con Edison prepared to handle such an emergency; and did Con Edison plan prudently reserve generation, for reserve transmission capability, for automatic equipment to protect its system, and for proper operator response to a critical situation. Following the introductory and summary section, additional sections include: the Consolidated Edison system; prevention of bulk power-supply interruptions; the sequence of failure and restoration; analysis of the July 1977 power failure; restoration sequence and equipment damage assessment; and other investigations of the blackout. (MCW)

  16. Simplified analytical methods for the measurement of the synthesis rate of plasma proteins in vivo by the (/sup 14/C)carbonate method

    Energy Technology Data Exchange (ETDEWEB)

    Caine, S [Glasgow Royal Infirmary (UK); Fleck, A [Charing Cross Hospital, London (UK). Medical School

    1984-09-01

    A method is described for obtaining the specific activity of /sup 14/C in urea, essential in the measurement of the synthesis rate of a plasma protein in vivo, which is simpler than the original procedure. The principle is the measurement of /sup 14/CO/sub 2/ and NH/sub 4//sup +/ separately, after incubation with urease. A simple alteration gives samples of /sup 13/CO/sub 2/ for mass spectrometry. The 'recoveries' of /sup 14/C and /sup 13/C in urea were invariably between 90 and 96% and the CV was 3%.

  17. Resistencia al desgaste de recubrimientos Bi/NbC producidos con el sistema sputtering con magnetrón desbalanceado

    OpenAIRE

    Ardila Rodríguez, Laura Angélica

    2013-01-01

    En este trabajo se produjeron películas nano estructuradas de NbC, Bi y bicapas Bi/NbC sobre acero M2 y 316L mediante la técnica Sputtering con magnetrón desbalanceado, y se evaluó su resistencia frente al desgaste por medio del ensayo pin on disc, la adherencia con una prueba de rayado y la resistencia a la corrosión de las películas depositadas sobre los sustratos 316L mediante técnicas electroquímicas. La microestructura de los recubrimientos se analizó mediante Difracción de rayos X, M...

  18. Urea incorporada, alternativa para el mejoramiento de la eficacia de la fertilización nitrogenada en el cultivo del arroz en aniego.

    Directory of Open Access Journals (Sweden)

    Pedro Antonio Meneses Dartayet

    2007-12-01

    Full Text Available El trabajo se realizó en la Estación Territorial de Investigaciones del Arroz (ETIA “Sur del Jíbaro” y en el Complejo Agropecuario e Industrial (CAI “Sur del Jíbaro”, durante los años 2006 y 2007, con el objetivo de evaluar la eficacia de la incorporación de la urea como fuente nitrogenada. El mismo constó de dos ensayos: Efecto de la incorporación de la urea hasta la profundidad de 20 cm. y su proporción con relación a la fertilización nitrogenada adicional en el momento de iniciación de la panícula, sobre el contenido relativo de nitrógeno y el rendimiento agrícola, realizado en la ETIA y Ensayo de validación en condiciones de producción de la incorporación de la urea, ejecutado en áreas del CAI arrocero. Los principales resultados mostraron que cuando se incorporó el 70 % del nitrógeno antes de la siembra y el restante 30 % del elemento, se suministró al momento de la iniciación de la panícula se obtuvo el mejor resultado en las condiciones de la ETIA; mientras que en condiciones de producción los resultados mostraron que en la variante donde se incorporó el nitrógeno la emisión de tallos improductivos se vio reducida significativamente, mientras el número de espiguillas por panículas y el llenado de las mismas se incrementó significativamente; de un modo semejante el rendimiento agrícola se mostró significativamente superior al testigo fraccionado, con un incremento de 0.48 t . ha-1 de arroz cáscara; todo lo cual sugiere que la disponibilidad de nitrógeno desde la etapa de plántula, conduce a la formación de tallos gruesos, vigorosos y uniformes, capaces de formar panículas sin anomalías y propiciar un incremento de la productividad.

  19. Standardization of the TRUE Test imidazolidinyl urea and diazolidinyl urea patches

    DEFF Research Database (Denmark)

    Agner, T; Andersen, Klaus Ejner; Björkner, B

    2001-01-01

    The preservatives imidazolidinyl urea (IMID, Germall 115) and diazolidinyl urea (DU, Germall II) are commonly used in cosmetic products and are well-known sensitizers. The aim of the present study was to establish the optimal patch test concentration in hydrophilic dried-in vehicle (TRUE Test...

  20. DHA Concentration and Purification from the Marine Heterotrophic Microalga Crypthecodinium cohnii CCMP 316 by Winterization and Urea Complexation

    Directory of Open Access Journals (Sweden)

    Ana Mendes

    2007-01-01

    Full Text Available A simple and inexpensive procedure involving saponification and methylation in wet biomass, winterization and urea complexation in a sequential way has been developed in order to concentrate docosahexaenoic acid (DHA from Crypthecodinium cohnii CCMP 316 biomass. Different urea/fatty acid ratios and crystallization temperatures were tested in the urea complexation method. ANOVA test revealed that, in the studied range, the temperature had the most significant effect on the DHA concentration. The highest DHA fraction (99.2 % of total fatty acids was found at the urea/fatty acid ratio of 3.5 at the crystallization temperatures of 4 and 8 °C. The highest DHA recovery (49.9 % was observed at 24 °C at the urea/fatty acid ratio of 4.0, corresponding to 89.4 % DHA of total fatty acids. Considering the high proportions of DHA obtained in the non-urea complexing fractions, the current procedure was an appropriate way to concentrate and purify DHA from C. cohnii.

  1. Rhodium catalyzed regioselective arene homologation of aryl urea via double C-H bond activation and migratory insertion of alkyne

    Institute of Scientific and Technical Information of China (English)

    Yan Wang; Hao Zhou; Ke Xu; Mei-Hua Shen; Hua-Dong Xu

    2017-01-01

    A convenient rhodium catalyzed oxidative arene homologation of aniline derivatives with symmetrical or unsymmetrical alkynes using Cu(OAc)2 as oxidant is described.Urea group is shown to be effective as a directing group for initial ortho C-H activation.Two migratory insertion events of alkyne into Rh-C bond occur successively,both with complete regioselectivity.This method is particularly useful for synthesis of polyarenes with different substituents,which has not been reported with conventional protocol.A mechanism has been proposed to explain the observed data.

  2. Pemanfaatan Urea sebagai Sumber Nitrogen pada Biosolubisasi Batubara oleh Trichoderma sp.

    Directory of Open Access Journals (Sweden)

    Novi Mulyawati

    2016-03-01

    Full Text Available Lignite coal was found abundant in Indonesia, but usage for this type of coal was still relatively low. Economic value of coal increases when it is solubilized. Biosolubilization of coal by utilize of microbes produces compounds equivalent to petroleum. In this research, effect of urea on lignite biosolubilization by Trichoderma sp. was examined. Method of this research consisted of spore inoculum preparation, biosolubilization lignite coal with a variety of treatment that consists of treatment A (MSS + sucrose  1% + coal 5% + urea, and treatment B (MSS + sucrose  1% + coal 5%. Results showed that the addition of urea supported lignit coal biosolubilization by Trichoderma sp. based on increase in medium pH, concentration of phenolic and conjugated aromatic compounds, and activity of extracellular enzyme. In addition, result of product characterization using GCMS revealed compounds equivalent to 13,60%, 26,20% and 90,8% respectively for gasoline, kerosene and diesel components. Those confirmed that urea can be used as an alternative nitrogen source to support Trichoderma sp. in lignit biosolubilization producing petroleum compounds.

  3. Can the C-14 urea breath test reflect the extent and degree of ongoing helicobacter pylori infection

    International Nuclear Information System (INIS)

    Lim, Seok Tae; Sohn, Myung Hee; Lee, Seung Ok; Lee, Soo Taik; Jeong, Myung Ja

    2001-01-01

    The C-14 urea breath test (C-14 UBT) is the most specific noninvasive method to detect Helicobacter (H) pylori infection. We investigated if the C-14 UBT can reflect the presence and degree of H. pylori detected by gastroduodenoscopic biopsies (GBx). One hundred fifty patients (M:F=83:67,age 48.6±11.2 yrs) underwent C-14 UBT, rapid urease test (CLO test) and GBx on the same day. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (137 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (≥200 dpm), intermediate ( 50 ∼ 199 dpm) or negative ( < 50 dpm). The results of CLO tests were classified as positive or negative according to color change. The results of GBx on giemsa stain were graded 0 (normal) to 4(diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT results with GBx grade as a gold standard. In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.5%, 88.4%, 97.1%, 88.4% and 91.3%, respectively. However, the CLO test had sensitivity, specificity, PPV, NPV and accuracy of 83.2%, 81.4%, 91.8%, 81.4% and 82.7%, respectively. The quantitative values of the C-14 UBT were 45 ± 27 dpm in grade 0, 707 ±584 dpm in grade 1, 1558±584 dpm in grade 2, 1851±604 dpm in grade 3, and 2719 ± 892 dpm in grade 4. A significant correlation (r=0.848, p<0.01) was found between C-14 UBT and the grade of distribution of H. pylori infection on GBx with giemsa stain. We conclude that the C-14 UBT is a highly accurate, simple and noninvasive method for the diagnosis of ongoing H. pylori infection and reflects the degree of bacterial distribution

  4. Neurological implications of urea cycle disorders

    Science.gov (United States)

    Summar, M.; Leonard, J. V.

    2013-01-01

    Summary The urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular 1H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate–nitric oxide–cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia-lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders. PMID:18038189

  5. Utilization of dietary urea in rainbow trout.

    Science.gov (United States)

    Kaushik, S J; Dabrowski, K R; Dabrowska, H; Olah, E; Luquet, P

    1983-01-01

    Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3% of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high (greater than 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 +/- 10.2 micrograms/ml) after a meal in the control fish and respectively 6 h (83.4 +/- 18.4 micrograms/ml) and 8 h (250.3 +/- 96.1 micrograms/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7-9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3% urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy demands.

  6. 40 CFR 721.6505 - Polymers of C13C15 oxoalcohol ethoxolates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of C13C15 oxoalcohol... Specific Chemical Substances § 721.6505 Polymers of C13C15 oxoalcohol ethoxolates. (a) Chemical substance... polymers of C13C15 oxoalcohol ethoxolates (PMNs P-96-950/951) are subject to reporting under this section...

  7. Efecto de la urea y del tiempo en la fermentación en estado sólido de la harina de frutos del árbol del pan (Artocarpus altilis

    Directory of Open Access Journals (Sweden)

    Odelin Brea-Maure

    2015-07-01

    Full Text Available Para evaluar el efecto de la inclusión de niveles de urea y del tiempo sobre los indicadores fermentativos y químicos de la harina de frutos del árbol del pan, fermentada en estado sólido, se mezcló homogéneamente con esta, sulfato de magnesio (0,2%, premezcla mineral (0,5% y agua destilada. Se utilizó un diseño completamente aleatorizado con arreglo factorial (4x4, con 4 repeticiones por tratamiento para evaluar el efecto de la urea (0; 0,5; 1,0 y 1,5% y cuatro tiempos de fermentación (0, 12, 24 y 48 h. En el estudio, a medida que se incrementa el nivel de urea, aumenta la concentración de amoníaco y, por ende, el pH, lo que depende, en menor o mayor grado, de la concentración de los ácidos orgánicos (AGCC y láctico. Al final del proceso fermentativo hubo una disminución en la MS (P<0,001 a medida que transcurrió el tiempo de fermentación. La adición de 1,5% de urea produjo un incremento en la concentración de PB a las 24 y 48 h sin diferencia entre ellos; algo similar ocurrió con la PV y la relación entre ellos (PV:PB*100 sin interacción entre los factores en estudios. A las 48 h hubo un aumento mayor de 2,15 unidades porcentuales en la PB con respecto a la hora cero. Se concluye que la adición de urea en el proceso de fermentación de la harina de frutos del árbol del pan en estado sólido incrementa la síntesis de proteína microbiana.

  8. Measurement of urea kinetics in vivo by means of a constant tracer infusion of di-15N-urea

    International Nuclear Information System (INIS)

    Wolfe, R.R.

    1981-01-01

    We have assessed the feasibility of studying urea metabolism in vivo in both steady state and nonsteady state situations by means of the primed constant infusion of di-15N-urea and the analysis of the resulting enrichment in plasma urea. Both hepatectomized dogs with known rates of urea infusion and intact dogs were studied. The enrichment of the bistrimethylsilyl derivative of urea was determined on a gas chromatograph-mass spectrometer. Selected ion monitoring was set for m/e 189 (M - 15), m/e 190 (A + 1), and m/e 191 (A + 2), thus enabling the calculation of the rate of urea production from nonrecycled NH3 (from A + 2 data) (Ra N), the rate of recycling of NH3 into urea (Ra R) (from A + 1 data), and thus the total rate of urea production (Ra N + Ra R). When urine collections were made, the incorporation of urea-N into protein was estimated from the difference between Ra N and urea excretion. We found that, in the steady state in a hepatectomized dog, the rate of appearance of urea can be determined accurately. In the nonsteady state in both hepatectomized and intact dogs, urea appearance could be estimated within +/- 20% in most situations. The only situation in which this was not the case was when we attempted to measure rapid changes in Ra R. Thus, within limits, this can be a useful technique enabling the quantitation of various aspects of urea metabolism

  9. Synthesis of edatrexate (2-13C-glutamate)

    International Nuclear Information System (INIS)

    DeGraw, J.I.; Colwell, W.T.; Jue, Thomas

    1997-01-01

    The experimental antitumor drug Edatrexate, labeled with 99% 13 C at the 2-position of the glutamate acid group was required for 13 C-magnetic resonance spectroscopy studies in biological media. Coupling of 2,4-diamino-4-deoxy-10-ethyl-10-deazapteroic acid with diethyl L-2- 13 C-glutamate as promoted by BOP reagent afforded Edatrexate (2- 13 C-glu) diethyl ester in 60% yield following purification by column chromatography. Saponification by aqueous NaOH in 2-methoxyethanol gave the target molecule in 44% yield or 26% overall. (author)

  10. The C-12/C-13 abundance ratio in Comet Halley

    International Nuclear Information System (INIS)

    Wyckoff, S.; Lindholm, E.; Wehinger, P.A.; Peterson, B.A.; Zucconi, J.M.

    1989-01-01

    The individual (C-13)N rotational lines in Comet Halley are resolved using high-resolution spectra of the CN B2Sigma(+)-X2Sigma(+) (0,0) band. The observe C-12/C-13 abundance ratio excludes a site of origin for the comet near Uranus and Neptune and suggests a condensation environment quite distinct from other solar system bodies. Two theories are presented for the origin of Comet Halley. One theory suggest that the comet originated 4.5 Gyr ago in an inner Oort cloud at a heliocentric distance greater than 100 AU where chemical fractionation led to the C-13 enrichment in the CN parent molecule prior to condensation of the comet nucleus. According to the other, more plausible theory, the comet nucleus condensed relatively recently from the interstellar medium which has become enriches in C-13 and was subsequently gravitationally captured by the solar system. 107 refs

  11. IRMS detection of testosterone manipulated with {sup 13}C labeled standards in human urine by removing the labeled {sup 13}C

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingzhu, E-mail: wangjingzhu@chinada.cn [National Anti-Doping Laboratory, China Anti-Doping Agency, Beijing (China); Yang, Rui [Sport Science College, Beijing Sport University Beijing, Beijing (China); Yang, Wenning [School of Pharmacy, Beijing University of Chinese Medicine, Beijing (China); Liu, Xin; Xing, Yanyi; Xu, Youxuan [National Anti-Doping Laboratory, China Anti-Doping Agency, Beijing (China)

    2014-12-10

    Highlights: • {sup 13}C labeled testosterone can be used to adjust the isotope ratio of testosterone. • The novel testosterone cannot be detected by the regular IRMS method in doping test. • A method was explored to remove the labeled {sup 13}C. • The established method can be used to detect the manipulated testosterone. - Abstract: Isotope ratio mass spectrometry (IRMS) is applied to confirm testosterone (T) abuse by determining the carbon isotope ratios (δ{sup 13}C value). However, {sup 13}C labeled standards can be used to control the δ{sup 13}C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the {sup 13}C labeled atom at C-3 from the molecule of androsterone (Andro), the metabolite of T in urine, to produce the resultant (A-nor-5α-androstane-2,17-dione, ANAD). The difference in δ{sup 13}C values between Andro and ANAD (Δδ{sup 13}C{sub Andro–ANAD}, ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different {sup 13}C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ{sup 13}C{sub Andro–ANAD} post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ{sup 13}C{sub Andro–ANAD} for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3-{sup 13}C labeled standards.

  12. Site-specific 13C content by quantitative isotopic 13C Nuclear Magnetic Resonance spectrometry: A pilot inter-laboratory study

    International Nuclear Information System (INIS)

    Chaintreau, Alain; Fieber, Wolfgang; Sommer, Horst; Gilbert, Alexis; Yamada, Keita; Yoshida, Naohiro; Pagelot, Alain; Moskau, Detlef; Moreno, Aitor; Schleucher, Jürgen; Reniero, Fabiano; Holland, Margaret; Guillou, Claude; Silvestre, Virginie; Akoka, Serge; Remaud, Gérald S.

    2013-01-01

    Graphical abstract: -- Highlights: •First ring test on isotopic 13 C NMR spectrometry. •Evaluation of the intra- and inter-variability of the NMR spectrometers used. •Definition of a protocol for qualification of the performance of the spectrometer. -- Abstract: Isotopic 13 C NMR spectrometry, which is able to measure intra-molecular 13 C composition, is of emerging demand because of the new information provided by the 13 C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic 13 C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular 13 C composition by NMR. The main goals of the ring test were to establish intra- and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic 13 C NMR was then assessed on vanillin from three different origins associated with specific δ 13 C i profiles. The standard deviation was, on average, between 0.9 and 1.2‰ for intra-variability. The highest standard deviation for inter-variability was 2.1‰. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of δ 13 C i in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results

  13. Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate.

    Science.gov (United States)

    Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

    2013-12-06

    A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

  14. Synthesis and purification of 13C labelled xanthine derivatives

    International Nuclear Information System (INIS)

    Boukraa, M.S.; Deruaz, D.; Bannier, A.; Desage, M.; Brazier, J.L.

    1995-01-01

    3-[Methyl- 13 )C]xanthine, 7-[Methyl- 13 )C]xanthine, 1,3-[Dimethyl- 13 )C 2 ]xanthine (theophylline-1,3-[ 13 )CH 3 ] 2 ), 1,7-[Dimethyl- 13 )C 2 ]xanthine (paraxanthine-1,7[ 13 )CH 3 ] 2 ), and 3,7-[Dimethyl- 13 )C 2 ]xanthine (theobromine-3,7-[ 13 )CH 3 ] 2 were synthesized by nucleophilic substitution reaction(SN 2 ) from xanthine (X) and iodomethane-[ 13 C]. The 3-isobutylparaxanthine-7-[ 13 CH 3 ] was prepared from 3-isobutyl-1-methylxanthine (IBMX). The compounds were purified by reverse phase semipreparative liquid chromatography and their chemical structure and purity verified by GC-MS. (Author)

  15. LOW FRACTIONAL EXCRETION OF UREA IN HYPOTHYROIDISM INDUCED HYPONATREMIA

    Directory of Open Access Journals (Sweden)

    Algranati L

    2005-01-01

    Full Text Available RESUMEN:El hipotiroidismo puede causar alteraciones del metabolismo del agua, los electrolitos, la hemodinamia e histología renales, siendo la hiponatremia y la reducción del filtrado glomerular sus consecuencias más significativas, pero poco prevalentes. Todos estos cambios son corregibles con el suministro de hormona tiroidea exógena.La excreción fraccional de urea (EFU es un índice útil en la evaluación de la hiponatremia, pero no se ha descripto aun el valor que este índice alcanza en la hiponatremia inducida por hipotiroidismo. En el presente reporte mostramos que la EFU y excreción fraccional de sodio (EFNa fueron baja (EFU: 29% y alta (EFNa: 2.2% respectivamente en un paciente que padecía hipotiroideo severo. El tratamiento con hormona tiroidea normalizó el valor de ambos índices.ABSTRACTHypothyroidism can cause disturbance of renal hemodinamics, kidney histology, water and electrolyte metabolism, being hyponatremia and glomerular filtration reduction their low prevalent but most significant consequences. All these changes are largely corrected by substitution of exogenous thyroid hormone.Fractional excretion of urea (FEU is a useful index in the evaluation of hyponatremia. However, it was not still reported in the literature the FEU value in hyponatremia induced by hypothyroidism. Because of that we presented a case report showing that the value of FEU and fractional excretion of sodium (FENa were low (FEU: 29% and high (FENa: 2.2 % respectively in a severe hypothyroid patient. Treatment based on thyroid hormone normalized both indeces.

  16. Breve Reseña Histórica de la Evolución de la Cirugía.

    OpenAIRE

    Gilberto Rueda Pérez

    2007-01-01

    Si admiramos las obras maestras de Miguel Angel en la Capilla Sixtina del Vaticano, podemos observar cómo el artista interpreta magistralmente el Génesis que dice: Dios“Y formó Yahvé al hombre del polvo de la tierra y le insuflò aliento de vida, de modo que el hombre vino a ser alma viviente”. Pero el hombre estaba sólo y “entonces Yavé hizo caer un profundo sueño sobre el hombre, el cual se durmió; y le quitó una de las costillas y cerró con carne el lugar de la misma. De la...

  17. Accurate determination of 13C/12C in CO2 of past atmospheres from 13C/12C in tree rings by removal of climatic interferences. Final technical progress report

    International Nuclear Information System (INIS)

    Long, A.; Leavitt, S.W.

    1982-07-01

    Analysis of delta 13 C in tree rings offers the potential for reconstructing changes in delta 13 C of atmospheric CO 2 , which combined with 14 C trends will be important in evaluating the past and present role of the biosphere as a net carbon dioxide source or sink. One problem with such tree-ring delta 13 C records is that in addition to changes in atmospheric delta 13 C, climatic factors may influence the isotopic composition of the rings. This study examines delta 13 C in cellulose of five-year intervals of juniper tree rings. The sampling sites were near weather stations for which climate data are readily available. delta 13 C vs winter climate relationships were derived from those sites not under the influence of local pollution sources. These relationships facilitated development of a delta 13 C record from which climate effects have been factored out. The resulting 1930-1979 delta 13 C reconstruction shows a pronounced delta 13 C decrease from 1930 to 1960 and then a post-1960 flattening of the curve. We interpret this trend as representing an increasing role of biospheric CO 2 sinks relative to sources, although other interpretations may be possible within the limits of precision of data analysis. Research with this technique is continuing with pinyon pine and dendroclimatological reconstructions to verify these results and to develop a climate-free delta 13 C chronology back to pre-industrial time

  18. The permeability of red blood cells to chloride, urea and water

    DEFF Research Database (Denmark)

    Brahm, Jesper

    2013-01-01

    This study extends permeability (P) data on chloride, urea and water in red blood cells (RBC), and concludes that the urea transporter (UT-B) does not transport water. P of chick, duck, Amphiuma means, dog and human RBC to (36)Cl(-), (14)C-urea and (3)H2O was determined under self....... Temperature dependence, as measured by apparent activation energy, EA, of PCl is 117.8 (duck), 74.9 (Amphiuma) and 89.6 kJ mol(-1) (dog). The EA of Purea is 69.6 (duck) and 53.3 kJ mol(-1) (Amphiuma), and that of Pd is 34.9 (duck) and 32.1 kJ mol(-1) (Amphiuma). The present and previous RBC studies indicate......-exchange conditions. At 25°C and pH 7.2-7.5, PCl is 0.94×10(-4)-2.15×10(-4) cm s(-1) for all RBC species at [Cl]=127-150 mmol l(-1). In chick and duck RBC, Purea is 0.84×10(-6) and 1.65×10(-6) cm s(-1), respectively, at [urea]=1-500 mmol l(-1). In Amphiuma, dog and human RBC, Purea is concentration dependent (1...

  19. Dispersion Interactions between Urea and Nucleobases Contribute to the Destabilization of RNA by Urea in Aqueous Solution

    Science.gov (United States)

    Kasavajhala, Koushik; Bikkina, Swetha; Patil, Indrajit; MacKerell, Alexander D.; Priyakumar, U. Deva

    2015-01-01

    Urea has long been used to investigate protein folding and, more recently, RNA folding. Studies have proposed that urea denatures RNA by participating in stacking interactions and hydrogen bonds with nucleic acid bases. In this study, the ability of urea to form unconventional stacking interactions with RNA bases is investigated using ab initio calculations (RI-MP2 and CCSD(T) methods with the aug-cc-pVDZ basis set). A total of 29 stable nucleobase-urea stacked complexes are identified in which the intermolecular interaction energies (up to −14 kcal/mol) are dominated by dispersion effects. Natural bond orbital (NBO) and atoms in molecules (AIM) calculations further confirm strong interactions between urea and nucleobases. Calculations on model systems with multiple urea and water molecules interacting with a guanine base lead to a hypothesis that urea molecules along with water are able to form cage-like structures capable of trapping nucleic acid bases in extrahelical states by forming both hydrogen bonded and dispersion interactions, thereby contributing to the unfolding of RNA in the presence of urea in aqueous solution. PMID:25668757

  20. PRODUCCIÓN DE TRES VARIEDADES DE Pennisetum purpureum FERTILIZADAS CON DOS DIFERENTES FUENTES NITROGENADAS EN YUCATÁN, MÉXICO

    Directory of Open Access Journals (Sweden)

    Ramos Trejo O

    2013-01-01

    Full Text Available El objetivo del trabajo fue evaluar el rendimiento (t MS ha-1 año-1 y porcentaje de proteína cruda (calidad nutritiva del pasto King grass (KNG y los clones Cubanos OM-22 y CT-115, fertilizadas con dos fuentes nitrogenadas. Las parcelas se establecieron con varetas de material vegetativo de 25 cm de largo con dos a tres yemas en surcos a 10 cm de profundidad. El marco de siembra fue de 0.5 m entre plantas y 1.0 m entre hileras con orientación de Este a Oeste. Se utilizó Urea y Agua Residual Porcina (ARP como fuentes de nitrógeno (N a dosis de 300 Kg de N ha-1 año-1. Se encontró diferencia significativa (p<0.05 en producción de materia seca (MS entre las tres variedades de forraje, el mayor rendimiento fue para el OM-22 con 155 y 160 t MS ha-1 año -1 con el uso de Urea y ARP, respectivamente. Se observó la misma tendencia con KNG con rendimiento de 131 a 140 t de MS ha-1 año-1. Las variedades OM-22, CT-115 y KNG fueron diferentes estadísticamente (p<0.05 al tratamiento testigo. No se observó efecto en la composición química por la aplicación de N. Se obtuvieron valores entre 8 y 12 % de proteína cruda (PC en los tres ecotipos. Se concluye que la fertilización con las dos fuentes nitrogenadas (Urea y ARP mejora la producción de forraje en los tres ecotipos evaluados.

  1. Metabolic pathways for ketone body production. 13C NMR spectroscopy of rat liver in vivo using 13C-multilabeled fatty acids

    International Nuclear Information System (INIS)

    Pahl-Wostl, C.; Seelig, J.

    1986-01-01

    The hormonal regulation of ketogenesis in the liver of living rat has been studied noninvasively with 13 C nuclear magnetic resonance. The spatial selection for the liver was better than 90%, with extrahepatic adipose tissue contribution only a very small amount of signal. The metabolic activities of the liver were investigated by infusion of 13 C-labeled butyrate in the jugular vein of the anesthetized rat. The rate of butyrate infusion was chosen to be close to the maximum oxidative capacity of the rat liver, and the 13 C signal intensities were enhanced by using doubly labeled [1,3- 13 C]butyrate as a substrate. Different 13 C NMR spectra and hence different metabolites were observed depending on the hormonal state of the animal. The 13 C NMR studies demonstrate that even when rate of acetyl-CoA production are high, the disposal of this compound is not identical in fasted and diabetic animals. This supports previous suggestions that the redox state of the mitochondrion represents the most important factor in regulation. For a given metabolic state of the animal, different signal intensities were obtained depending on whether butyrate was labeled at C-1, C-3, or C-1,3. From the ratios of incorporation of 13 C label into the carbons of 3-hydroxybutyrate, it could be estimated that a large fraction of butyrate evaded β-oxidation to acetyl-CoA but was converted directly to acetoacetyl-CoA. 13 C-labeled glucose could be detected in vivo in the liver of diabetic rats

  2. Determination of fructose metabolic pathways in normal and fructose-intolerant children: A 13C NMR study using [U-13C]fructose

    International Nuclear Information System (INIS)

    Gopher, A.; Lapidot, A.; Vaisman, N.; Mandel, H.

    1990-01-01

    An inborn deficiency in the ability of aldolase B to split fructose 1-phosphate is found in humans with hereditary fructose intolerance (HFI). A stable isotope procedure to elucidate the mechanism of conversion of fructose to glucose in normal children and in HFI children has been developed. A constant infusion of D-[U- 13 C]fructose was given nasogastrically to control and to HFI children. Hepatic fructose conversion to glucose was estimated by examination of 13 C NMR spectra of plasma glucose. Significantly lower values (∼3-fold) for fructose conversion to glucose were obtained for the HFI patients as compared to the controls. A quantitative determination of the metabolic pathways of fructose conversion to glucose was derived from 13 C NMR measurement of plasma [ 13 C]glucose isotopomer populations. The finding of isotopomer populations of three adjacent 13 C atoms at glucose C-4 ( 13 C 3 - 13 C 4 - 13 C 5 ) suggests that there is a direct pathway from fructose, by-passing fructose-1-phosphate aldolase, to fructose 1,6-bisphosphate. The metabolism of fructose by fructose-1-phosphate aldolase activity accounts for only ∼50% of the total amount of hepatic fructose conversion to glucose. In view of the marked decline by 67% in synthesis of glucose from fructose in HFI subjects found in this study, the extent of [ 13 C]glucose formation from a trace amount of [U- 13 C]fructose infused into the patient can be used as a safe and noninvasive diagnostic test for inherent faulty fructose metabolism

  3. Non-stationary (13)C-metabolic flux ratio analysis.

    Science.gov (United States)

    Hörl, Manuel; Schnidder, Julian; Sauer, Uwe; Zamboni, Nicola

    2013-12-01

    (13)C-metabolic flux analysis ((13)C-MFA) has become a key method for metabolic engineering and systems biology. In the most common methodology, fluxes are calculated by global isotopomer balancing and iterative fitting to stationary (13)C-labeling data. This approach requires a closed carbon balance, long-lasting metabolic steady state, and the detection of (13)C-patterns in a large number of metabolites. These restrictions mostly reduced the application of (13)C-MFA to the central carbon metabolism of well-studied model organisms grown in minimal media with a single carbon source. Here we introduce non-stationary (13)C-metabolic flux ratio analysis as a novel method for (13)C-MFA to allow estimating local, relative fluxes from ultra-short (13)C-labeling experiments and without the need for global isotopomer balancing. The approach relies on the acquisition of non-stationary (13)C-labeling data exclusively for metabolites in the proximity of a node of converging fluxes and a local parameter estimation with a system of ordinary differential equations. We developed a generalized workflow that takes into account reaction types and the availability of mass spectrometric data on molecular ions or fragments for data processing, modeling, parameter and error estimation. We demonstrated the approach by analyzing three key nodes of converging fluxes in central metabolism of Bacillus subtilis. We obtained flux estimates that are in agreement with published results obtained from steady state experiments, but reduced the duration of the necessary (13)C-labeling experiment to less than a minute. These results show that our strategy enables to formally estimate relative pathway fluxes on extremely short time scale, neglecting cellular carbon balancing. Hence this approach paves the road to targeted (13)C-MFA in dynamic systems with multiple carbon sources and towards rich media. © 2013 Wiley Periodicals, Inc.

  4. Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

    NARCIS (Netherlands)

    Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

    2012-01-01

    In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

  5. Glomerulonefritis C3: una nueva categoría de glomerulonefritis con implicaciones etiopatogénicas

    OpenAIRE

    Taborda Murillo, Alejandra; Arroyave Suárez, Mariam José; Arias, Luis Fernando

    2015-01-01

    Introducción: las glomerulonefritis con depósitos exclusivos de la fracción C3 del complemento (GN-C3) pueden implicar alteración en la vía alterna de este. Objetivos: describir retrospectivamente una serie de casos de GN-C3 y determinar la frecuencia con que los pacientes continúan con alteraciones renales y/o hipocomplementemia. Métodos: se evaluaron las características histológicas y clínicas y la evolución de los 22 casos de GN-C3 diagnosticados entre 2004 y 2012 en el Departamento de Pat...

  6. Hojas de cálculo para el análisis de losas combinadas con pilotes

    Directory of Open Access Journals (Sweden)

    Luis Ibañez

    2013-08-01

    Full Text Available En el diseño de cimentaciones en balsas combinadas con pilotes, se determina un gran número de incógnitas de forma tal que se obtenga una cimentación racional y que a su vez cumpla con los requerimientos de proyecto. El empleo de hojas de cálculo, facilita el trabajo del proyectista, al poder predimensionar la cimentación, evaluando la influencia de los diferentes parámetros que intervienen en el diseño, para finalmente utilizar programas de cómputos para el cálculo definitivo. En este trabajo se muestran los resultados obtenidos con hojas de cálculo programadas en MathCad y se comparan los valores de la curva estimada carga vs deformación de las hojas de cálculo con resultados de modelos a escala real y otros de la literatura sobre el tema.

  7. Adolescente femenino con granulomatosis de Wegener fulminante

    Directory of Open Access Journals (Sweden)

    S C Scheffler-Mendoza

    2017-01-01

    Full Text Available Adolescente femenino de 13 años de edad, originaria de Guerrero, grupo étnico mixteco, padres analfabetos y con poco entendimiento del español. Sin otros antecedentes de importancia para el padecimiento. Inició un mes previo con la aparición de una pápula hipercrómica en párpado superior derecho que en los 10 días previos al ingreso aumentó de volumen generando proptosis. Al interrogatorio se negó dolor, lagrimeo, fiebre, o pérdida de peso. Ingresó con fiebre (39.0°C, palidez generalizada, proptosis derecha con exposición de córnea y conjuntiva, eritema periorbitario, movimientos oculares y agudeza visual disminuidos (i.e. contaba dedos a 1 m, pupila con tendencia a midriasis, hiperreactividad a la luz, y fondo de ojo con papila hiperémica edematosa y tortuosidad peripapilar. El resto de exploración no mostró datos relevantes. Se hospitalizó para iniciar tratamiento antimicrobiano parenteral de amplio espectro (i.e. ceftriaxona y vancomicina y abordar proptosis unilateral.

  8. Investigation of the association between glaucoma and Helicobacter pylori infection using the {sup 14}C-urea breath test

    Energy Technology Data Exchange (ETDEWEB)

    Tuzcu, Esra Ayhan; Aydogan, Fusun; Motor, Vicdan Koksaldi; Ilhan, Ozgur; Daglioglu, Mutlu Cihan; Coskun, Mesut; Parlakfikirer, Nihan; Keskin, Ugurcan, E-mail: drayhant@hotmail.com [Medical Faculty, Mustafa Kemal University, Hatay (Turkey)

    2015-07-01

    Purpose: to investigate the association between glaucoma and Helicobacter pylori infection by evaluating for the presence of H. pylori infection in patients with glaucoma using the 14C-urea breath test (14C-UBT). Methods: Using 14C-UBT, H. pylori infection positivity was compared between a group of patients with primary open-angle glaucoma and a control group with normal intraocular pressure and a normal optic disc or normal perimetry. Results: the 14C-UBT was positive in 18 (51.42%) out of 35 patients in the glaucoma group and in 15 (42.85%) out of 35 patients in the control group. H. pylori infection positivity rates were similar between the glaucoma and control groups (p>0.05). Conclusion: according to the 14C-UBT, there is no association between primary open-angle glaucoma and H. pylori infection. (author)

  9. Biokinetics of 13C in the human body after oral administration of 13C-labeled glucose as an index for the biokinetics of 14C.

    Science.gov (United States)

    Masuda, Tsuyoshi; Tako, Yasuhiro; Matsushita, Kensaku; Takeda, Hiroshi; Endo, Masahiro; Nakamura, Yuji; Hisamatsu, Shun'ichi

    2016-09-01

    The retention of 13 C in the human body after oral administration of 13 C-labeled glucose was studied in three healthy volunteer subjects to estimate the 50 year cumulative body burden for 13 C as an index of the committed dose of the radioisotope 14 C. After administration of 13 C-labeled glucose, the volunteers ingested controlled diets with a fixed number of calories for 112 d. Samples of breath and urine were collected up to 112 d after administration. Samples of feces were collected up to 14 d after administration. Hair samples were obtained at 119 d after administration and analyzed as a representative index of the rate of excretion of organic 13 C via pathways such as skin cell exfoliation and mucus secretion. All samples were analyzed for 13 C/ 12 C atomic ratio to determine the rate of excretion via each pathway. We then constructed a metabolic model with a total of four pathways (breath, urine, feces, and other) comprising seven compartments. We determined the values of the biokinetic parameters in the model by using the obtained excretion data. From 74% to 94% of the 13 C administered was excreted in breath, whereas    0.1). In addition, the dataset for one of the three subjects was markedly different from those of the other two. When we estimated the 50 year cumulative body burden for 13 C by using our model and we included non-statistically significant parameters, a considerable cumulative body burden was found in the compartments excreting to the other pathway. Although our results on the cumulative body burden of 13 C from orally administered carbon as glucose were inconclusive, we found that the compartments excreting to the other pathway had a markedly long residence time and therefore should be studied further to clarify the fate of carbon in the human body. In addition to excreta, data for serum and blood cell samples were also collected from the subjects to examine the metabolism of 13 C in human body.

  10. 12C(d,p) 13C reaction at Esub(d) = 30 MeV to the positive-parity states in 13C

    International Nuclear Information System (INIS)

    Ohnuma, H.; Hoshino, N.; Mikoshiba, O.

    1985-07-01

    The 12 C(d, p) 13 C reaction has been studied at Esub(d) = 30 MeV. All the known positive-parity states of 13 C below 10 MeV in excitation energy, including the 7/2 + and 9/2 + states, are observed in this reaction. The angular distributions for these positive-parity bound and unbound states are analyzed in CCBA frame work. The 13 C wave functions, which reproduce the resonant and non-resonant scattering of neutrons from 12 C, also give good accounts of the experimentally observed angular distributions and energy spectra of outgoing protons in the 12 C(d, p) 13 C reaction. In most cases the cross section magnitude and the angular distribution shape are primarily determined by the 0 + x j component, even if it is only a small fraction of the total wave function. An exception is the 7/2 + state, where the main contribution comes from the 2 + x dsub(5/2) component. The inclusion of the 4 + state in 12 C and the gsub(9/2) and gsub(7/2) neutron components in the n + 12 C system has very small effects on the low-spin states, but is indispensable for a good fit to the 7/2 + and 9/2 + angular distributions. The transitions to the negative-parity states, 1/2 1 - , 3/2 1 - , 5/2 - , 7/2 - and 1/2 3 - , are also observed experimentally, and analyzed by DWBA. (author)

  11. An optimized and simplified method for analysing urea and ammonia in freshwater aquaculture systems

    DEFF Research Database (Denmark)

    Larsen, Bodil Katrine; Dalsgaard, Anne Johanne Tang; Pedersen, Per Bovbjerg

    2015-01-01

    This study presents a simple urease method for analysis of ammonia and urea in freshwater aquaculture systems. Urea is hydrolysed into ammonia using urease followed by analysis of released ammonia using the salicylate-hypochlorite method. The hydrolysis of urea is performed at room temperature...... and without addition of a buffer. A number of tests were performed on water samples obtained from a commercial rainbow trout farm to determine the optimal urease concentration and time for complete hydrolysis. One mL of water sample was spiked with 1.3 mL urea at three different concentrations: 50 lg L 1, 100...... lg L 1 and 200 lg L 1 urea-N. In addition, five concentrations of urease were tested, ranging from 0.1 U mL 1 to 4 U mL 1. Samples were hydrolysed for various time periods ranging from 5 to 120 min. A urease concentration of 0.4 U mL 1 and a hydrolysis period of 120 min gave the best results, with 99...

  12. Synthesis of 15N-enriched fertilizers. Pt. II. Synthesis of 15N-enriched urea

    International Nuclear Information System (INIS)

    Bondassolli, J.A.; Trivelin, P.C.O.; Mortatti, J.; Victoria, R.L.

    1988-01-01

    The results of studies on the production of 15 N-urea through the reaction between 15 N-enriched anhidrous ammonia, carbon monoxide and sulfur, using hydrogen sulfite as a auto catalizers and methyl alcohol as a liquid reaction medium is presented. The influence of the quantities of reagents on final yield of synthesised urea were studied. Analysis of the cost of 5 Atoms % 15 N-enriched urea were made. (M.A.C.) [pt

  13. Improvement of Egyptian vacuum distillates by urea dewaxing

    Directory of Open Access Journals (Sweden)

    Ehssan M.R. Nassef

    2015-09-01

    Full Text Available The dewaxing of paraffinic lube stocks is an essential step in the production of lubricants to improve the operability of machines especially in winter. The present work deals with study of the urea dewaxing process of two types of Egyptian vacuum distillates. The effect of different compositions of methanol to water saturated with urea and yield of the oil, percent of wax, pour point, refractive index, viscosity, viscosity index and specific gravity of the oil produced from the two types of distillates (I and II were evaluated. The operating conditions of the urea adduct formation with n-paraffins using methanol to water mixture achieved the best pour point at −3.88 °C from an initial temperature of 4.4 °C for distillate I at (25/75 methanol to water. At the same ratio of methanol to water the best specific gravity of oil produced changed from 0.865 to 0.867, with viscosity index of 80. Percent yield of 50% for oil and percent wax of 50% were obtained. Results for distillate II, of higher specific gravity, are comparatively higher than those for distillate I. Experiments were carried out at room temperature.

  14. Vivir con cáncer: una experiencia de cambios profundos provocados por la quimioterapia

    Directory of Open Access Journals (Sweden)

    Paula Jaman-Mewes

    2014-01-01

    Full Text Available Objetivo: develar las experiencias de mujeres chilenas con cáncer en tratamiento con quimioterapia. Materiales y método: estudio de investigación cualitativa fenomenológica según el pensamiento filosófico de Martín Heidegger. Se entrevistaron en profundidad a 10 mujeres entre 45 y 64 años, con diferentes diagnósticos de cáncer en tratamiento con quimioterapia. El análisis se realizó basado en el método de Streubert y Carpenter, triangulando con un investigador experto. Resultados: la experiencia de vivir con cáncer y con quimio- terapia significa estar “viviendo con un tratamiento que provoca cambios profundos en la vida de las mujeres”, siendo esta una categoría comprensiva esencial del estudio que contiene cuatro unidades de significados: 1 cambios en todas las dimensiones del “ser” de las mujeres tanto a nivel corporal como emocional y espiritual; 2 cambios en el “ser-sí-misma”: antes y durante la quimioterapia; 3 cambios de “ser” en el mundo; 4 cambios en la familia. Conclusiones: la comprensión en profundidad de lo vivido por las mujeres de este estudio confirma lo publicado en la literatura, y se constituye en un saber comprensivo que puede servir de guía para realizar cuidados de enfermería oncológicos humanos y personalizados basados en las necesidades de cada persona.

  15. Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

    Directory of Open Access Journals (Sweden)

    Kasra Saeedfar

    2013-12-01

    Full Text Available A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate (PnBA membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor’s sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor’s response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

  16. A Modular Synthesis of N-Benzotriazole Ureas Using Alkylation of 5-Nitrobenzotriazole

    Czech Academy of Sciences Publication Activity Database

    Machara, A.; Konvalinka, Jan; Kotora, M.

    2016-01-01

    Roč. 1, č. 1 (2016), s. 101-107 ISSN 2365-6549 R&D Projects: GA ČR GA13-19561S Institutional support: RVO:61388963 Keywords : benzotriazole * alkylation * urea * isocyanate * reduction Subject RIV: CE - Biochemistry

  17. Effects of nitrogen supply on inter-organ fluxes of urea-N and renal urea-N kinetics in lactating Holstein cows

    DEFF Research Database (Denmark)

    Røjen, Betina Amdisen; Theil, Peter Kappel; Kristensen, Niels Bastian

    2011-01-01

    The effects of decreasing ruminal urea infusion in lactating dairy cows fed a basal diet deficient in rumen degradable protein on inter-organ urea-N fluxes, epithelial urea-N extraction, and renal urea-N kinetics were investigated. Eight Danish Holstein cows fitted with a ruminal cannula...... and permanent indwelling catheters in the major splanchnic blood vessels and the gastrosplenic vein were used. The cows were randomly allocated to a triplicate incomplete 3 × 3 Latin square design with 14-d periods. Treatments were continuous ventral ruminal infusion of water, 4.1 g of feed urea/kg of dry...... matter intake, and 8.5 g of feed urea/kg of dry matter intake. Dry matter intake and milk yield decreased linearly with decreasing urea infusion. Arterial blood urea-N and ruminal ammonia concentrations decreased linearly with decreasing urea infusion. In absolute amounts, the urea-N recycling did...

  18. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias).

    Science.gov (United States)

    Wood, Chris M; Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J

    2013-01-01

    The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L(-1) urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L(-1) with osmotic compensation by 175 mmol L(-1) mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L(-1)) to those of urea (175 mmol L(-1)), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  19. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias

    Directory of Open Access Journals (Sweden)

    Chris M. Wood

    2013-02-01

    Full Text Available The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L−1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L−1 with osmotic compensation by 175 mmol L−1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L−1 to those of urea (175 mmol L−1, urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  20. Excitation functions of the systems 12C+14C and 13C+12C

    International Nuclear Information System (INIS)

    Haindl, E.

    1975-01-01

    The excitation functions of the systems 12 C+ 14 C and 13 C+ 12 C are investigated for different exit channels. The excitation functions measured do not show correlated structures as in the system 12 C+ 12 C. (WL/AK) [de

  1. Filtros de vena cava en pacientes con cáncer

    Directory of Open Access Journals (Sweden)

    Fernando A. Díaz Couselo

    2012-08-01

    Full Text Available Los pacientes con tromboembolismo venoso (TEV y cáncer tienen más complicaciones vinculadas al tratamiento anticoagulante que la población general. Los filtros de vena cava constituyen una herramienta útil para el tratamiento del TEV y su utilización es controvertida en estadios avanzados de la enfermedad. En este trabajo se revisaron las indicaciones, complicaciones y frecuencia de retiro de los filtros de vena cava en una población de pacientes oncológicos con TEV. Se analizaron 27 pacientes a quienes se les había colocado filtros de vena cava. Veinticinco tenían tumores sólidos y dos linfomas no Hodgkin. Veinticinco estaban bajo tratamiento activo (cirugía y/o quimioterapia. Diecinueve se hallaban en estadio IV de su enfermedad. El motivo de su indicación fue profilaxis en el período perioperatorio en 14 casos (51.9%, hemorragia (n = 5, trombocitopenia (n = 4, metástasis en sistema nervioso central (n = 2, accidente cerebrovascular (n = 1 y neurocirugía previa no reciente (n = 1. Se retiraron 8 (29.6% filtros. La mediana del tiempo de permanencia fue 21 días (6-75. No hubo diferencias estadísticamente significativas en la frecuencia de retiro entre los filtros colocados en el perioperatorio (6/14 y los colocados por otras contraindicaciones para la anticoagulación (2/13; p = 0.2087. No hubo fracasos ni complicaciones en los procedimientos de colocación y retiro.

  2. Mutagenic activity of N-nitrosoethylene urea in higher plants. [C. cappilaris L

    Energy Technology Data Exchange (ETDEWEB)

    Sal' nikova, T.V.; Grigorova, N.V.; Laputin, D.L.; Shustova, L.L., Zazimko, V.V.; Shustov, G.V.; Kostyanovskiy, R.G.

    1984-04-01

    Cytopathogenetic effect of N-nitrosoethylene urea (NETM) on common wheat and C. cappilaris L. are studied. Air-dried wheat seeds were treated with 1 of 5 concentrations (0.1-0.01%) of NETM for 18 hours at pH 5.7 or 7.0. Treatment of seeds with NETM reduced the germinating power significantly at pH 5.7, especially at high concentrations of NETM. NETM is also a highly effective chemical mutagen. Maximum mutagenic effect appears at pH 7.0. NETM greatly reduced mitotic activity of wheat and C. cappilaris L. which is typical for alkylating type mutagens. The aberration rate is rather high for both objects studied. In both the anaphase and metaphase method of calculating chromosomal injuries, a great percentage of the total number of aberrations are chromatid type reconstructions which indicates predominance of the alkylating action of NETM. Wheat affected by NETM has a large number of anaphase cells with lagging chromosome which is atypical for alkylating type mutagens. This may be explained by the effect of NETM on centromeric and precentromeric parts of chromosomes and spindle filaments. NETM is an alkylating agent rather than a carbamoylating agent. It is a highly active and slightly toxic mutagen. 25 references, 1 figure.

  3. Funcionalidad de las relaciones intrafamiliares en los pacientes con cáncer

    OpenAIRE

    Jairzinho Granados-Villamil; Jessica Paola Parada-Mise; Yeiny Marcela Cáceres-Serrano

    2014-01-01

    Objetivo: medir el nivel de funcionalidad de las relaciones intrafamiliares del núcleo familiar de los pacientes con cáncer, inscritos en un programa de lucha contra el cáncer. Materiales y Métodos: estudio descriptivo, de corte transversal con un abordaje cuantitativo. La población objeto de estudio son 165 pacientes, 83 pacientes y 82 cuidadores que corresponden al total de pacientes y su cuidador. Para recolectar la información se aplicó el instrumento evaluación de las relaciones intrafam...

  4. Urea adsorption by activated carbon prepared from palm kernel shell

    Science.gov (United States)

    Ooi, Chee-Heong; Sim, Yoke-Leng; Yeoh, Fei-Yee

    2017-07-01

    Dialysis treatment is crucial for patients suffer from renal failure. The dialysis system removes the uremic toxin to a safe level in a patient's body. One of the major limitations of the current hemodialysis system is the capability to efficiently remove uremic toxins from patient's body. Nanoporous materials can be applied to improve the treatment. Palm kernel shell (PKS) biomass generated from palm oil mills can be utilized to prepare high quality nanoporous activated carbon (AC) and applied for urea adsorption in the dialysis system. In this study, AC was prepared from PKS via different carbonization temperatures and followed by carbon dioxide gas activation processes. The physical and chemical properties of the samples were studied. The results show that the porous AC with BET surface areas ranging from 541 to 622 m2g-1 and with total pore volumes varying from 0.254 to 0.297 cm3g-1, are formed with different carbonization temperatures. The equilibrium constant for urea adsorption by AC samples carbonized at 400, 500 and 600 °C are 0.091, 0.287 and 0.334, respectively. The increase of carbonization temperatures from 400 to 600 °C resulted in the increase in urea adsorption by AC predominantly due to increase in surface area. The present study reveals the feasibility of preparing AC with good porosity from PKS and potentially applied in urea adsorption application.

  5. Role of thin descending limb urea transport in renal urea handling and the urine concentrating mechanism

    Science.gov (United States)

    Lei, Tianluo; Zhou, Lei; Layton, Anita T.; Zhou, Hong; Zhao, Xuejian; Bankir, Lise

    2011-01-01

    Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts. PMID:21849488

  6. Inference of past atmospheric delta13C and P/sub CO2/ from 13C/12C measurements in tree rings

    International Nuclear Information System (INIS)

    Leavitt, S.W.

    1982-01-01

    Carbon dioxide release from fossil-fuel burning is significant enough that we may soon experience perceptible changes in climate with important human consequences. An accurate reconstruction of past 13 C/ 12 C ratios of atmospheric CO 2 may provide key constraints on the historical activity of the biosphere as CO 2 source or sink. Tree rings appear to be a repository of this information but there is much noise in the collection of previous reconstructions, presumably associated with site selection, radial variability, choice of representative wood chemical constituent, and subtle effects of climate on fractionation. This study attempts to avoid these pitfalls and develop a 50-yr delta 13 C/sub ATM/ record from juniper trees (genus Juniperus), in fact, by taking advantage of the influence of climate on fractionation. Trees were harvested from suitable sites in close proximity to weather stations with monthly records of temperature and precipitation. The most useful relationships for at most 7 of the 10 sites were delta 13 C with December temperature or precipitation, because the coefficients were nearly constant from one interval to the next and the intercepts differed. Local pollution effects are believed responsible for the three anomalous sites. The separation of these regression lines of different intervals is interpreted as the response of the trees to the changing delta 13 C of atmospheric CO 2 so that delta 13 C/sub ATM/ curves are constructed from this spacing. The shape of the best-fit reconstruction suggests the biosphere has acted as CO 2 source to about 1965 and may now be a net sink

  7. Biokinetics and radiation dosimetry of 14C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Gunnarsson, Mikael

    2002-08-01

    14 C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used 14 C-breath tests: 14 C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low 14 C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform 14 C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of 14 C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: 14 C-glycocholic acid - 0.4 mSv/MBq, 14 C-triolein - 0.3 mSv/MBq, 14 C-xylose - 0.1 mSv/MBq and 14 C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the 14 C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  8. Toward Understanding Mechanisms Controlling Urea Delivery in a Coastal Plain Watershed

    Science.gov (United States)

    Tzilkowski, S. S.; Buda, A. R.; Boyer, E. W.; Bryant, R. B.; May, E. B.

    2012-12-01

    Improved understanding of nutrient mobilization and delivery to surface waters is critical to protecting water quality in agricultural watersheds. Urea, a form of organic nitrogen, is a common nutrient found in fertilizers, manures, and human waste, and is gaining recognition as an important driver of coastal eutrophication, particularly through the development of harmful algal blooms. While several studies have documented elevated urea concentrations in tributaries draining to the Chesapeake Bay, little is known about the potential sources and flow pathways responsible for urea delivery from the landscape to surface waters, as well as how these sources and pathways might vary with changing seasons, antecedent conditions, and storm types. In this study, we investigated hydrologic controls on urea delivery in the Manokin River watershed through the analysis of urea concentration dynamics and hysteresis patterns during seven storm events that occurred in 2010 and 2011. The Manokin River is a Coastal Plain watershed (11.1 km2) on the Delmarva Peninsula that drains directly to the Chesapeake Bay and is characterized by extensive rural development coupled with intensive agriculture, particularly poultry production. Sampling was conducted through monthly grab sampling at baseflow conditions and by time-weighted, automated (Sigma) samplers during stormflow events. Monitored storms were chosen to represent a spectrum of antecedent conditions based on precipitation and groundwater levels in the area. Flushing from the landscape during events was found to be the predominant urea delivery mechanism, as urea concentrations increased 3-9 times above baseflow concentrations during storms. The timing and number of flushes, as well as the degree of increased concentrations were dependent on antecedent conditions and the characteristics of the storm event. For instance, during an intense (13.7 mm hr-1), short-duration (4 hrs) storm in August of 2010 when antecedent conditions were

  9. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.; Silks, L.A. III

    1994-01-01

    The authors are currently developing new synthetic routes to the various isotopomers of glycerol. Labeled glycerol is useful for 13 C enrichment of biomolecules. However, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment or have poor overall yields (12-15%). In addition, the use of glycerol for enrichment can be prohibitively expensive and its availability depends on the level of demand. The authors have developed a short de novo synthesis of [U- 13 C]glycerol from carbon dioxide (∼53% overall yield for four steps) and are currently examining the feasibility of synthesizing site-specific 13 C labeled glycerol and dihydroxyacetone (DHA) from methanol and carbon dioxide. The authors have examined the enzymatic conversion of [U- 13 C]glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25-50% (as determined by NMR spectroscopy). The authors are also pursuing the chemical conversion of 13 C labeled DHA to DHAP and the results are presented. Labeled DHAP is a possible enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids

  10. Distribuciones simuladas de valores de d13c de colágeno humano: implicancias para los estudios paleodietarios

    Directory of Open Access Journals (Sweden)

    Barrientos, Gustavo

    2005-01-01

    Full Text Available El objetivo de este trabajo es presentar los primeros resultados derivados de la aplicación de un programa de simulación de distribuciones de valores de δ13C de colágeno humano (DeltaCarb130.0, desarrollado por los autores. DeltaCarb130.0 es un programa simple que simula la composición isotópica (δ13C del colágeno de huesos humanos obtenida a través de una dieta de composición variable, constituida por tres ingestas diarias, durante un período de 1825 días (5 años. La composición de la dieta y los valores de δ13C de cada recurso dietario (vegetales C3 y C4, carne de herbívoros consumidores de C3 y C4, de mamíferos marinos, de peces y moluscos se obtienen, en cada etapa de la simulación, a través de un proceso aleatorio a partir de datos de abundancia relativa y rangos de valores de δ13C de cada tipo de recurso. Se analizarán estadísticamente las distribuciones de valores de δ13C obtenidas a partir de n corridas del programa para cada combinación dietaria, con la finalidad de obtener medidas de tendencia central y de dispersión asociadas a cada tipo de dieta y calcular la probabilidad de obtener valores "outliers", un rasgo frecuente en el estudio de casos arqueológicos.

  11. Oxidation of urea-derived nitrogen by thaumarchaeota-dominated marine nitrifying communities.

    Science.gov (United States)

    Tolar, Bradley B; Wallsgrove, Natalie J; Popp, Brian N; Hollibaugh, James T

    2017-12-01

    Urea nitrogen has been proposed to contribute significantly to nitrification by marine thaumarchaeotes. These inferences are based on distributions of thaumarchaeote urease genes rather than activity measurements. We found that ammonia oxidation rates were always higher than oxidation rates of urea-derived N in samples from coastal Georgia, USA (means ± SEM: 382 ± 35 versus 73 ± 24 nmol L -1  d -1 , Mann-Whitney U-test p  0.05). Urea-derived N was relatively more important in samples from Antarctic continental shelf waters, though the difference was not statistically significant (19.4 ± 4.8 versus 12.0 ± 2.7 nmol L -1  d -1 , p > 0.05). We found only weak correlations between oxidation rates of urea-derived N and the abundance or transcription of putative Thaumarchaeota ureC genes. Dependence on urea-derived N does not appear to be directly related to pH or ammonium concentrations. Competition experiments and release of 15 NH 3 suggest that urea is hydrolyzed to ammonia intracellularly, then a portion is lost to the dissolved pool. The contribution of urea-derived N to nitrification appears to be minor in temperate coastal waters, but may represent a significant portion of the nitrification flux in Antarctic coastal waters. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Association of serum uric acid with blood urea and serum creatinine

    International Nuclear Information System (INIS)

    Haq, A.U.; Ahmad, Z.; Rehman, J.U.

    2010-01-01

    Background: Hyperuricemia can cause serious health problems including renal insufficiency. Hyperuricemia is associated with many diseases including Hypertension, Diabetes Mellitus, Hypertriglyceridemia and Obesity. Objective of the present study was to study the Association of Serum Uric Acid with Blood Urea and Serum Creatinine. Methods: Eighty subjects, aged above 40, having blood urea more than 40 mg/dl and serum Creatinine more than 1.3 mg/dl were selected. 52.5 % subjects were male. Eighty subjects were selected as control group matching the age and sex with study group with normal blood urea and serum Creatinine. Results: Serum Uric Acid was found to be raised in 33 patients. Mean Serum Uric Acid value was 6.98+-2.021 in males (p<0.05) and 5.054+-2.324 in females (p<0.05). Conclusion: Serum Uric Acid is raised in patients with impaired renal function (p<0.05). Levels of increased Serum Uric Acid were not significantly associated with the cause of renal disease. (author)

  13. Laboratory spectra of C-13 ethane

    Science.gov (United States)

    Kurtz, Joe; Reuter, Dennis C.; Jennings, Donald E.; Hillman, John J.

    1991-01-01

    The laboratory infrared spectrum of C-13 monosubstituted ethane has been obtained at high resolution (0.0025/cm) using the McMath Fourier transform spectrometer at Kitt Peak National Observatory in May 1990. A preliminary analysis of the nu12 rQ0 branch (substituted species) suggests that its intensity is 1.15 + or - 0.05 times stronger than the equivalent nu9 branch in the normal (C-12)2H6 species. This result leads to a correction of a previously published estimate for the C-12/C-13 ratio in the atmosphere of Jupiter from about 94 to about 106.

  14. Determination of urea content in urea cream by centrifugal partition chromatography

    Directory of Open Access Journals (Sweden)

    Ying-Qun Wang

    2016-04-01

    Full Text Available The objective of this study is to establish a centrifugal partition chromatography (CPC method for determination of the urea ingredient in urea cream. The mechanism of this method is that urea is determined by UV detector at 430 nm after being extracted from the cream and derivatized on line via Ehrlich reaction in rotor of CPC, where the reaction products dissolve in the mobile phase and the cream matrix retains in the stationary phase. The mixed solvent consisting of n-hexane, methanol, hydrochloric acid and p-dimethylaminobenzaldehyde with a ratio of 1000 mL:1000 mL:18 mL:2.0 g is used for solvent system of CPC. The CPC method proposed offers good precision and convenience without complex sample pretreatment processes.

  15. NMR study of conjugation effects. 15. /sup 13/C-/sup 13/C spin-spin coupling constants in phenylalkyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Kalabin, G.A. (Siberian Branch of the Academy of Sciences of the USSR); Krivdin, L.B.; Trofimov, B.A.

    1982-07-20

    In order to elucidate the /sup 13/C-/sup 13/-C SSCC (spin-spin coupling constants) segment with the electronic excitations induced by the R group, a series of phenyl alkyl ethers, PhOAlk, where Alk = Me(I), Et(II), i-Pr(III), and t-Bu(IV), were studied. This series was chosen because in studying the /sup 13/C CS in monosubstituted benzenes it was observed that the intensity of the ..pi..-electron interaction of the unshared electron pairs of oxygen with the ..pi.. system of the benzene ring was practically the same in some compounds, but increased by 30% in others. This is related to the fact that the latter is characterized by an average noncoplanar conformation, with a dihedral angle between the benzene-ring plane and the C-O-C bond of approx. 45/sup 0/, whereas some compounds have an angle < 20/sup 0/. The reason for the difference is significant steric interaction of the alkyl hydrogens with the o-position of the ring. Thus, consideration of the /sup 13/C-/sup 13/C SSCC of a series of quite similar compounds, especially when compared to the whole set of such SSCC for other monosubstituted benzenes, shows that their relationship to the structure of the substituent R is extremely complex.

  16. Probing the possibility of a C-12/C-13 galactic abundance gradient

    International Nuclear Information System (INIS)

    Hawkins, I.

    1990-01-01

    High S/N (equal to or greater than 500) observations of interstellar CH+ with the 3.0 m telescope were performed at Lick Observatory and with the 4.0 m telescope at CTIO, of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a C-12/C-13 abundance gradient in our Galaxy. Previous very high quality optical observations of interstellar CH+ toward five stars within 1 kpc of the Sun have yielded a precise weighted mean C-12/C-13 isotope ratio of 43 plus or minus 4 (1 sigma) (Hawkins, Jura, and Meyer 1985; Hawkins and Jura 1987). The isotope ratios derived toward four lines of sight in the local ISM are uniform within 12 percent. The similarity among these carbon isotope ratios determined in diffuse clouds possessing different physical conditions precludes the possibility that the CH+ molecule is suffering from isotope selective effects in these regions. The precise C-12/C-13 derivable from high quality observations of (12)CH+ and (13)CH+ provide the unique opportunity to probe the homogeneity of the ISM in a large scale and the history of nucleosynthesis in our Galaxy. Since CH+ seems to be the most sensitive probe of C-12/C-13 in the diffuse ISM, observations toward more distant stars located up to 2.5 kpc from the Sun are the best way to study the possibility of a Galactic (C-12/C-13) abundance gradient. The researcher obtained 4232 angstrom data toward all three of the stars mentioned above, 3957 angstrom data toward HD 183143 and HD 157038, and 3745 angstrom data toward HD 157038. Because of the poorer quality of the HD 24432 spectrum, and its weaker CH+ absorption lines, the satellite (13)CH+ line was not detected, and thus only a lower limit on the C-12/C-13 ratio toward this star was obtained. The results obtained from careful reduction and analysis of the data toward these stars in the Northern and Southern Hemispheres are presented

  17. Ammonia volatilization from coated urea forms

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Costa do Nascimento

    2013-08-01

    Full Text Available Nitrogen fertilization is a major component of the cost of agricultural production, due to the high cost and low efficiency of fertilizers. In the case of urea, the low efficiency is mainly due to losses by volatilization, which are more pronounced in cultivation systems in which plant residues are left on the soil. The objective of this work was to compare the influence of urea coated with sulfur or boric acid and copper sulfate with conventional N fertilizers on N volatilization losses in sugar cane harvested after stubble burning. The sources urea, sulfur-coated urea, urea coated with boric acid and copper sulfate, as well as nitrate and ammonium sulfate, were tested at amounts containing N rates of 120 kg ha-1 N. The integration of new technologies in urea fertilization can reduce N losses by volatilization. These losses were most reduced when using nitrate and ammonium sulfate. The application of a readily acidified substance (boric acid to urea was more efficient in reducing volatilization losses and nutrient removal by sugar cane than that of a substance with gradual acidification (elemental sulfur.

  18. SRS-sensor 13C/12C isotops measurements for detecting Helicobacter Pylori

    Science.gov (United States)

    Grishkanich, Aleksandr; Chubchenko, Yan; Elizarov, Valentin; Zhevlakov, Aleksandr; Konopelko, Leonid

    2018-02-01

    We developed SRS-sensor 13C/12C isotops measurements detecting Helicobacter Pylori for medical diagnostics of human health. Measuring of absolute 13C/12C isotope amount ratios allows to explore the topical problems of the modern world, alcoholic beverages and tobacco, medical diagnostics of human health. SRS method is used to measure the ratio of carbon isotopes in the exhaled carbon dioxide, which is used to diagnose the human infection of Helicobacter pylori and the influence of the Helicobacter pylori bacterium on the occurrence of gastritis, gastric and duodenal ulcers. A method for the analysis of human infection with Helicobacter pylori was developed on the basis of measurements of the ratio of 13C / 12C carbon isotopes in human exhaled air with a high level of measurement accuracy. The article reviews the work in the field of provision comparability of absolute 13C/12C isotope amount ratios in the environment and food. The analysis of the technical and metrological characteristics of traditional and perspective instruments for measuring isotope ratios is presented. The provision of comparability of absolute 13C/12C isotope amount ratios is carried by gravimetrically prepared reference standards. The key features and emerging issues are discussed.

  19. Urea-molasses liquid diet feeding for growth produion in cattle and buffalo

    International Nuclear Information System (INIS)

    Pathak, N.N.; Ranjhan, S.K.; Singh, U.B.

    1974-01-01

    As a part of the study to find the utilization of urea-molasses liquid for growth and maintenance in cattle and buffaloes, production rate of volatile fatty acids (VFAs) was measured by single injection isotope dilution technique using 1-2 14 C-acetate in adult cattle and buffaloes fed ad libitum urea-molasses diet with restricted wheat straw and intact protein. (M.G.B.)

  20. Increases in urea synthesis and the ornithine-urea cycle capacity in the giant African snail, Achatina fulica, during fasting or aestivation, or after the injection with ammonium chloride.

    Science.gov (United States)

    Hiong, Kum Chew; Loong, Ai May; Chew, Shit Fun; Ip, Yuen Kwong

    2005-12-01

    the foot muscle of A. fulica increased 4.5- and 33-fold at hour 12 and hour 24, respectively, and the respective increases in the hepatopancreas were 4.9- and 32-fold. The exogenous ammonia injected into A. fulica was apparently detoxified completely to urea. The urea synthesis rate increased 148-fold within the 24-hr experimental period, which could be the greatest increase known among animals. Simultaneously, there were significant increases in activities of glutamine synthetase (2.5-fold), CPS III (3.1-fold), ornithine transcarbamoylase (2.3-fold), argininosuccinate synthetase+lyase (13.6-fold) and arginase (3.5-fold) in the hepatopancreas 12 hr after the injection of NH(4)Cl. Taken altogether, our results support the view that the primary function of urea synthesis through the OUC in A. fulica is to defend against ammonia toxicity, but suggest that urea may have more than an excretory role in terrestrial pulmonates capable of aestivation.

  1. Radiochemical investigation of the bioaccumulation of urea by the alga Hydrodictyon reticulatum

    International Nuclear Information System (INIS)

    Havelka, M.; Stary, J.; Kratzer, K.

    1987-01-01

    It is found that the bioaccumulation of 14 C-urea in the light is connected with the increase of pH-value of the external medium, of the intracellular concentration of ammonium ions and with the decrease of the intracellular concentration of potassium ions. The uptake rate does not depend on the concentration of urea in the range from 0.1 to 2.0 mmol dm -3 and it has a broad maximum at pH 6.5-8.0. The uptake rate of urea is a little higher compared with nitrite or nitrate anions, however it is at least three times lower in comparison with that of ammonium or hydrocarbonate ions. The uptake of urea in the dark leads to the increase of the intracellular concentration of ammonium ions, however, carbon dioxide formed is released from the cell. (author) 7 refs

  2. Analgesia preventiva y multimodal con ketamina y dipirona en mastectomía radical por cáncer de mama

    Directory of Open Access Journals (Sweden)

    Miladys Justo Hernández

    2015-11-01

    Full Text Available El dolor agudo es frecuente en los pacientes que requieren intervención quirúrgica; su tratamiento satisfactorio es uno de los retos más importantes, presentando ventajas la terapéutica multimodal y preventiva. Se realizó un estudio longitudinal, prospectivo en 22 pacientes, a los que se les practicó mastectomía radical por cáncer de mama, con el objetivo de describir el uso de la analgesia multimodal y preventiva con ketalar y dipirona en el manejo del dolor posoperatorio de estos pacientes. La técnica anestésica utilizada fue total intravenosa, con propofol y fentanyl, dosis convencional. En el postoperatorio se vigiló la aparición de efectos colaterales. Los datos se colocaron en tablas de contingencia, procesados mediante el sistema de cálculos estadísticos que presenta Microsoft Excel. El análisis se realizó fundamentalmente a través de medidas de resúmenes, porcentaje y media aritmética. Se concluyó que la analgesia multimodal preventiva con ketamina y dipirona fue efectiva y segura en todos los casos, a los que se realizó radical de mama. Predominó el grupo de edad entre 46 y 65 años y ASA II. Las variables hemodinámicas y respiratorias se mantuvieron estables en todos los pacientes. No necesitaron analgesia de rescate. La somnolencia se manifestó en 13,6% de los casos.

  3. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-01-01

    Due in part to the use of labeled glycerol for the 13 C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide (∼53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific 13 C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of 13 C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of 13 C-labeled DHA to DHAP. We are especially interested in 13 C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids

  4. Neutron orbital radii in {sup 13} C; Radios orbitales neutronicos en {sup 13} C

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera R, E.F.; Murillo, G.; Ramirez, J.J.; Avila, O.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1988-01-15

    In this work its were carried out experimental measurements of the reaction {sup 12}C(d,p) {sup 13}C at low energy. Preliminary results of a DWBA analysis of the data are presented, and the possibility of using this reaction to obtain the orbital radius of the transferred neutron is investigated. (Author)

  5. 40 CFR 721.9892 - Alkylated urea.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under this...

  6. 40 CFR 721.9928 - Urea, tetraethyl-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Urea, tetraethyl-. 721.9928 Section... Substances § 721.9928 Urea, tetraethyl-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as urea, tetraethyl- (PMN P-94-1017; CAS No. 1187-03-7) is...

  7. NMR structure analysis of uniformly 13C-labeled carbohydrates.

    Science.gov (United States)

    Fontana, Carolina; Kovacs, Helena; Widmalm, Göran

    2014-06-01

    In this study, a set of nuclear magnetic resonance experiments, some of them commonly used in the study of (13)C-labeled proteins and/or nucleic acids, is applied for the structure determination of uniformly (13)C-enriched carbohydrates. Two model substances were employed: one compound of low molecular weight [(UL-(13)C)-sucrose, 342 Da] and one compound of medium molecular weight ((13)C-enriched O-antigenic polysaccharide isolated from Escherichia coli O142, ~10 kDa). The first step in this approach involves the assignment of the carbon resonances in each monosaccharide spin system using the anomeric carbon signal as the starting point. The (13)C resonances are traced using (13)C-(13)C correlations from homonuclear experiments, such as (H)CC-CT-COSY, (H)CC-NOESY, CC-CT-TOCSY and/or virtually decoupled (H)CC-TOCSY. Based on the assignment of the (13)C resonances, the (1)H chemical shifts are derived in a straightforward manner using one-bond (1)H-(13)C correlations from heteronuclear experiments (HC-CT-HSQC). In order to avoid the (1) J CC splitting of the (13)C resonances and to improve the resolution, either constant-time (CT) in the indirect dimension or virtual decoupling in the direct dimension were used. The monosaccharide sequence and linkage positions in oligosaccharides were determined using either (13)C or (1)H detected experiments, namely CC-CT-COSY, band-selective (H)CC-TOCSY, HC-CT-HSQC-NOESY or long-range HC-CT-HSQC. However, due to the short T2 relaxation time associated with larger polysaccharides, the sequential information in the O-antigen polysaccharide from E. coli O142 could only be elucidated using the (1)H-detected experiments. Exchanging protons of hydroxyl groups and N-acetyl amides in the (13)C-enriched polysaccharide were assigned by using HC-H2BC spectra. The assignment of the N-acetyl groups with (15)N at natural abundance was completed by using HN-SOFAST-HMQC, HNCA, HNCO and (13)C-detected (H)CACO spectra.

  8. Tamoxifeno y afecciones endometriales en pacientes con cáncer de mama

    Directory of Open Access Journals (Sweden)

    Delia B. Dalbert

    2013-04-01

    Full Text Available Los objetivos fueron evaluar la prevalencia de afecciones endometriales en pacientes tratadas con tamoxifeno (TAM y analizar los aspectos epidemiológicos, ecográficos, histeroscópicos e histopatológicos. Desde enero de 1999 a diciembre 2008 se estudiaron 152 pacientes con cáncer de mama tratadas con TAM (20 mg/día, sintomáticas (con sangrado o asintomáticas, pre y postmenopáusicas, incluidas en forma consecutiva. El diseño fue prospectivo y observacional. Los métodos diagnósticos usados fueron ecografía transvaginal, histeroscopía y biopsia. Las pacientes fueron seguidas durante 5 años con ecografía cada 12 meses e histeroscopia con biopsia en casos que lo justificaran. Edad: 62.76 ± 10.24 años y tiempo de tratamiento: 36.2 ± 19.9 meses. El adenocarcinoma se observó en 3/87 (3.45% pacientes con factores de riesgo y en 1/65 (1.54% sin ellos (RA: 1.91, IC 95% 1.88 a 1.94. Las afecciones benignas se hallaron en 148 pacientes (97.37% y los adenocarcinomas en 4 (2.63%,1 en un pólipo de aspecto benigno. Los 4 se observaron en mujeres postmenopáusicas (2 asintomáticas con grosor endometrial igual o mayor a 16 mm. El riesgo de cáncer fue significativamente mayor en sintomáticas (2.36 versus 0.42 en asintomáticas. Tres adenocarcinomas se detectaron entre 24 y 48 meses del tratamiento. Recomendamos un seguimiento con ecografía transvaginal de las pacientes asintomáticas, resección de los pólipos evaluando factores de riesgo y tiempo de exposición, en especial luego de los 24 meses. Consideramos aceptable un cut-off = 10 mm en el grosor del endometrio en postmenopáusicas asintomáticas para realizar histeroscopía y biopsia.

  9. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C

    Directory of Open Access Journals (Sweden)

    Zixun Chen

    2017-07-01

    Full Text Available Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.

  10. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C]methacetin- and [methyl-13C]methionine-breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Forberger, Anke; Wigger, Marianne

    2008-06-01

    The aim of this study was to investigate the hepatic microsomal and mitochondrial functions by using the 13CO2-breath test in healthy subjects either before or after the consumption of red wine. Fourteen adults received [13C]methacetin and [methyl-13C]methionine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol/kg/day together with dinner over a 10-day period. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2-enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery (CPDR) after administration of [13C]methacetin and [methyl-13C]methionine either without or with red wine consumption amounted to 38.2+/-6.3 vs. 36.3+/-6.7% (p=0.363) and 9.5+/-3.3 vs. 8.8+/-2.5% (p=0.47), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the mitochondrial functions of the human liver in healthy subjects.

  11. Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

    Science.gov (United States)

    Jennings, Donald E.; Nixon, C. A.; Romani, P. N.; Bjoraker, G. L.; Sada, P. V.; Lunsford, A. W.; Boyle, R. J.; Hesman, B. E.; McCabe, G. H.

    2009-01-01

    As the .main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS(exp 1) and from the ground and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes.

  12. Site-specific {sup 13}C content by quantitative isotopic {sup 13}C Nuclear Magnetic Resonance spectrometry: A pilot inter-laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Chaintreau, Alain; Fieber, Wolfgang; Sommer, Horst [Firmenich SA, Corporate R and D Division, P.O. Box 239, 1211 Geneva 8 (Switzerland); Gilbert, Alexis; Yamada, Keita [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Pagelot, Alain [Bruker Biospin SAS, 34 rue de l‘Industrie, 67166 Wissembourg Cedex (France); Moskau, Detlef; Moreno, Aitor [Bruker Biospin AG, Industriestrasse 26, 8117 Fällanden (Switzerland); Schleucher, Jürgen [Department of Medical Biochemistry and Biophysics, Umeå University, S-90187 Umeå (Sweden); Reniero, Fabiano; Holland, Margaret; Guillou, Claude [European Commission, Joint Research Centre – Institute for Health and Consumer Protection, via E. Fermi 2749, I-21027 Ispra (Italy); Silvestre, Virginie; Akoka, Serge [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Remaud, Gérald S., E-mail: gerald.remaud@univ-nantes.fr [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France)

    2013-07-25

    Graphical abstract: -- Highlights: •First ring test on isotopic {sup 13}C NMR spectrometry. •Evaluation of the intra- and inter-variability of the NMR spectrometers used. •Definition of a protocol for qualification of the performance of the spectrometer. -- Abstract: Isotopic {sup 13}C NMR spectrometry, which is able to measure intra-molecular {sup 13}C composition, is of emerging demand because of the new information provided by the {sup 13}C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic {sup 13}C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular {sup 13}C composition by NMR. The main goals of the ring test were to establish intra- and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic {sup 13}C NMR was then assessed on vanillin from three different origins associated with specific δ{sup 13}C{sub i} profiles. The standard deviation was, on average, between 0.9 and 1.2‰ for intra-variability. The highest standard deviation for inter-variability was 2.1‰. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of δ{sup 13}C{sub i} in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results.

  13. IMPROVED LINE DATA FOR THE SWAN SYSTEM 12C13C ISOTOPOLOGUE

    International Nuclear Information System (INIS)

    Ram, Ram S.; Brooke, James S. A.; Bernath, Peter F.; Sneden, Christopher; Lucatello, Sara

    2014-01-01

    We present new, accurate predictions for rotational line positions, excitation energies, and transition probabilities of the 12 C 13 C isotopologue Swan d 3 Π-a 3 Π system 0-0, 0–1, 0–2, 1–0, 1–1, 1–2, 2–0, 2–1, and 2–2 vibrational bands. The line positions and energy levels were predicted through new analyses of published laboratory data for the 12 C 13 C lines. Transition probabilities were derived from recent computations of transition dipole moments and related quantities. The 12 C 13 C line data were combined with similar data for 12 C 2, reported in a companion paper, and applied to produce synthetic spectra of carbon-rich metal-poor stars that have strong C 2 Swan bands. The matches between synthesized and observed spectra were used to estimate band head positions for a few of the 12 C 13 C vibrational bands and to verify that the new computed line data match observed spectra. The much weaker C 2 lines of the bright red giant Arcturus were also synthesized in the band head regions

  14. Diminished excretion of polyamines from BHK-21/C13 cells exposed to methylglyoxal bis(guanylhydrazone).

    Science.gov (United States)

    Melvin, M A; Keir, H M

    1978-01-01

    Methylglyoxal bis(guanylhydrazone) (1,1'-[methylethanediylidine)dinitrilo]diguanidine) inhibited the growth of BHK-21/C13 cells in monolayer cultures. Accumulation of spermidine and spermine was inhibited, whereas the accumulation of putrescine was increased. The intracellular spermidine/spermine molar ratio decreased conly slightly after exposure of the cells to 20 micrometer-methylglyoxal bis(guanylhydrazone) for 1 day. Cells incubated in the presence of the drug released less polyamine into the culture medium that did control cells, the polyamine released consisting almost exclusively of spermidine, both free and as a conjugated form. PMID:697761

  15. Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose

    Science.gov (United States)

    Moran, Nancy E.; Rogers, Randy B.; Lu, Chi-Hua; Conlon, Lauren E.; Lila, Mary Ann; Clinton, Steven K.; Erdman, John W.

    2013-01-01

    While putative disease-preventing lycopene metabolites are found in both tomato (Solanum lycopersicum) products and in their consumers, mammalian lycopene metabolism is poorly understood. Advances in tomato cell culturing techniques offer an economical tool for generation of highly-enriched 13C-lycopene for human bioavailability and metabolism studies. To enhance the 13C-enrichment and yields of labeled lycopene from the hp-1 tomato cell line, cultures were first grown in 13C-glucose media for three serial batches and produced increasing proportions of uniformly labeled lycopene (14.3 +/− 1.2 %, 39.6 +/− 0.5 %, and 48.9 +/− 1.5% with consistent yields (from 5.8 to 9 mg/L). An optimized 9-day-long 13C-loading and 18-day-long labeling strategy developed based on glucose utilization and lycopene yields, yielded 13C-lycopene with 93% 13C isotopic purity, and 55% of isotopomers were uniformly labeled. Furthermore, an optimized acetone and hexane extraction led to a four-fold increase in lycopene recovery from cultures compared to a standard extraction. PMID:23561155

  16. Nivel de adaptación y afrontamiento en las mujeres con cáncer de mama

    Directory of Open Access Journals (Sweden)

    Yoeli Leyva-Pescador

    2011-12-01

    Full Text Available Introducción: El cáncer de mama constituye una amenaza para la salud por ser la segunda causa de muerte en la mujer de 30 a 50 años de edad. El diagnostico, tratamiento y recuperación de las mujeres con cáncer de mama genera situaciones estresantes, la forma en cómo se afrontan influye en la adaptación. Objetivo: Conocer el nivel de adaptación y afrontamiento de las mujeres con cáncer de mama, atendidas en una institución de salud de Durango, Dgo. México. Materiales y Métodos: Estudio descriptivo cuantitativo, aplicando instrumento validado en población mexicana con un (alfa .7969, "escala de medición del proceso de afrontamiento y adaptación" de Callista Roy" en 22 mujeres con cáncer de mama. Resultados: Las mujeres con cáncer de mama se adaptan y afrontan su problema de salud, con un nivel de adaptación integrado y compensatorio pudiendodistinguir que dónde presenta dificultad es en el modo físico y fisiológico. Discusión y Conclusiones: De acuerdo al estudio "ajuste psicosocial y afrontamiento en pacientes con cáncer de mama" se encuentra una diferencia en que los participantes no experimentaron cambios a partir de la enfermedad contraria a nuestro trabajo ya que los participantes adquieren nuevas posibilidades y capacidades. La adaptación de las mujeres que han padecido cáncer de mama es un proceso dinámico, enfrentan múltiples desequilibrios que afectan sus dimensiones emocional, física, mental y social. Se pudo conocer el nivel de adaptación y afrontamiento de las mujeres con cáncer de mama comprobando que en su mayoría presentan un nivel de adaptación integrado y compensatorio. (Rev Cuid 2011; 2(2: 96- 104Palabras clave: Adaptación Psicológica, Atención de Enfermería, Cáncer de Mama. (Fuente: DeCs BIREME.

  17. Urea route to coat inorganic nanowires, carbon fibers and nanotubes by boron nitride

    International Nuclear Information System (INIS)

    Gomathi, A.; Ramya Harika, M.; Rao, C.N.R.

    2008-01-01

    A simple route involving urea as the nitrogen source has been employed to carry out boron nitride coating on carbon fibers, multi-walled carbon nanotubes and inorganic nanowires. The process involves heating the carbon fibers and nanotubes or inorganic nanowires in a mixture of H 3 BO 3 and urea, followed by a heat treatment at 1000 deg. C in a N 2 atmosphere. We have been able to characterize the BN coating by transmission electron microscopy as well as X-ray photoelectron spectroscopy. The urea decomposition route affords a simple method to coat boron nitride on one-dimensional nanostructures

  18. Noninvasive brain metabolism measurement using carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS); Tanso 13 jiki kyomei spectroscopy ({sup 13}C-MRS) ni yoru mushinshuteki notaisha keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, K.; Tsukada, Y. [Toshiba Corp., Tokyo (Japan)

    1998-10-10

    Carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS) and research and development efforts for brain metabolism measurement are described. Brain metabolism is a process characterized in that it not only extracts energy by disintegrating grape sugar that is the practically sole source of energy into H2O, CO2, etc., but also vigorously synthesizes amino acids that perform important functions in neural transmission, such as glutamic acid, glutamine, and {gamma}-amino acid. MRS is a technique that utilizes the magnetic resonance, which is generated when an atomic nucleus with a spin is placed in a magnetic field, for the isolation and identification of chemicals in a living body through examining the delicate difference in the magnetic resonance frequencies of the nuclei under observation. Since the signals from {sup 13}C are low in intensity as compared with those from other nuclides, a method was contrived around 1980, which observes {sup 1}H combined with {sup 13}C in grape sugar and amino acids, named the HSQC (heteronuclear single quantum coherence) method. The author et al., combining gradient magnetic pulses with HSQC, actually measure Homo sapiens brain metabolism using {sup 13}C-MRS, and now believe that the technology will be put to practical application. 7 refs., 10 figs., 1 tab.

  19. Automated 13CO2 analyzing system for the 13C breath test

    International Nuclear Information System (INIS)

    Suehiro, Makiko; Kuroda, Akira; Maeda, Masahiro; Hinaga, Kou; Watanabe, Hiroyuki.

    1987-01-01

    An automated 13 CO 2 analyzing system for the 13 C breath test was designed, built and evaluated. The system, which was designed to be controlled by a micro-computer, includes CO 2 purification, 13 CO 2 abundance measurement, data processing and data filing. This article gives the description of the whole system with flow charts. This system has proved to work well and it has become feasible to dispose of 5 to 6 CO 2 samples per hour. With such a system, the 13 C breath test will be carried out much more easily and will obtain much greater popularity. (author)

  20. Waste-to-Chemicals for a Circular Economy: The Case of Urea Production (Waste-to-Urea).

    Science.gov (United States)

    Antonetti, Elena; Iaquaniello, Gaetano; Salladini, Annarita; Spadaccini, Luca; Perathoner, Siglinda; Centi, Gabriele

    2017-03-09

    The economics and environmental impact of a new technology for the production of urea from municipal solid waste, particularly the residue-derived fuel (RdF) fraction, is analyzed. Estimates indicate a cost of production of approximately €135 per ton of urea (internal rate of return more than 10 %) and savings of approximately 0.113 tons of CH 4 and approximately 0.78 tons of CO 2 per ton of urea produced. Thus, the results show that this waste-to-urea (WtU) technology is both economically valuable and environmentally advantageous (in terms of saving resources and limiting carbon footprint) for the production of chemicals from municipal solid waste in comparison with both the production of urea with conventional technology (starting from natural gas) and the use of RdF to produce electrical energy (waste-to-energy). A further benefit is the lower environmental impact of the solid residue produced from RdF conversion. The further benefit of this technology is the possibility to realize distributed fertilizer production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Aspectos psicológicos del paciente con cáncer

    Directory of Open Access Journals (Sweden)

    R. Labarca B.

    2017-05-01

    Full Text Available El profundo cambio que ha experimentado lamedicina en los últimos años, ha traído como consecuencia un deterioro en la relación médico-paciente. La consecuencia de este hecho es un distanciamiento entre médico y enfermo, situación que afecta seriamente a los pacientes con enfermedades incurables o terminales. El presente artículo revisa los aspectos psicológicos principales del enfermo con cáncer y concluye que la única actitud que cabe ante el enfermo canceroso es la verdadera relación médico-paciente.

  2. The urea cycle disorders.

    Science.gov (United States)

    Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

    2014-07-01

    The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows

    NARCIS (Netherlands)

    Spek, J.W.; Bannink, A.; Gort, G.; Hendriks, W.H.; Dijkstra, J.

    2013-01-01

    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl)

  4. (13)C MRS of human brain at 7 Tesla using [2-(13)C]glucose infusion and low power broadband stochastic proton decoupling.

    Science.gov (United States)

    Li, Shizhe; An, Li; Yu, Shao; Ferraris Araneta, Maria; Johnson, Christopher S; Wang, Shumin; Shen, Jun

    2016-03-01

    Carbon-13 ((13)C) MR spectroscopy (MRS) of the human brain at 7 Tesla (T) may pose patient safety issues due to high radiofrequency (RF) power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo (13)C MRS of human brain at 7 T using broadband low RF power proton decoupling. Carboxylic/amide (13)C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. (13)C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. At 7 T, the peak amplitude of carboxylic/amide (13)C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T (13)C MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively. In vivo (13)C MRS studies of human brain can be performed at 7 T, well below the RF safety threshold, by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. © 2015 Wiley Periodicals, Inc.

  5. 13C-NMR assignment, structure, and dynamics of deoxyoligonucleotides

    International Nuclear Information System (INIS)

    Zanatta, N.; Borer, P.N.; Levy, G.C.

    1986-01-01

    The unique spectral properties of 13 C-NMR for studying nucleic acids and some of the important features of 13 C-NMR in oligonucleotide studies are demostrated. The main difficulty in studying oligonucleotides by 13 C-NMR and recent improvements in NMR instrumentation and advances in oligonucleotide synthesis are presented. The high resolution 13 C-NMR spectra, T 1 relaxation times and NOEs were measured for duplex of the self-complementary oligo-DNAs: d(CG) 3 and d(GGTATACC) are studied. The target of this study is to developed a systematic 13 C-NMR spectral assignment and to investigate the structure and dynamics of these two sequences by this techniques. (M.J.C.) [pt

  6. Synthesis of {sup 14}C-labeled levamisole and {sup 13}C-labeled tetramisole

    Energy Technology Data Exchange (ETDEWEB)

    Feil, V.J. [US Department of Agriculture, Agricultural Research Service, Biosciences Research Lab., Fargo, ND (United States)

    1996-12-01

    The syntheses of {sup 14}C-ring labeled levamisole ([-]-2,3,5,6-tetrahydro-6-phenyl [{sup 14}C]-UL imidazo[2,1-b]thiazole) from acetophenone-ring-UL-{sup 14}C in 5 steps plus resolution with a 7.5% overall yield, and {sup 13}C{sub 6}-ring labeled tetramisole ([{+-}]-2,3,5,6-tetrahydro-6-phenyl [{sup 13}C{sub 6}]imidazo[2,1-b]thiazole) from benzene-{sup 13}C{sub 6} in 6 steps with a 9.0% overall yield are described. (author).

  7. Transport of C-13-labelled linoleic and C-13-labelled caprylic acid in rat plasma after administration of specific structured triacylglycerols

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Høy, Carl-Erik

    2004-01-01

    the transport of dietary C-13-labelled fatty acids in rat plasma to compare the chylomicron fatty acid metabolism after administration of specific structured, long chain and medium chain triacylglycerols. Rats were fed ML*M, M*LM*, L*L*L* or M*M*M* (L=linoleic acid, 18:2n-6, M=caprylic acid, 8:0, * = C-13......-labelled fatty acid) by gavage. A maximum transport of 0.5% of the administered C-13-labelled 18:2n-6 was observed in 1mL rat plasma both after administration of L*L*L* and ML*M, while approximately 0.04% of the administered C-13-labelled 8:0 was detected in 1mL plasma following administration of M......*M*M* or M*LM*. After L*L*L* administration C-13-labelled 20:4n-6 was observed in plasma, probably formed by elongation and desaturation of 18:2n-6 in the enterocyte or liver cells. Furthermore, C-13-labelled 16:0, 48:0, 18: 1n-9 and 20:4n-6 were observed in plasma of rats fed M*M*M* and M*LM* due...

  8. Nitrogen waste from rainbow trout (Oncorhynchus mykiss) with particular focus on urea

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang; Larsen, Bodil Katrine; Pedersen, Per Bovbjerg

    2015-01-01

    a laboratory, mass-balance approach, the current study examined the effects of commercially applied feeding levels on the loading of different N waste forms, including daily fluctuations in dissolved total nitrogen (TN), total ammonia nitrogen (TAN), urea-N, and non-characterized, dissolved N deriving from...... juvenile rainbow trout (Oncorhynchus mykiss). In addition, the study examined whether there was a removal of urea-N across a moving bed biofilter operated as end-of-pipe under commercial conditions. The laboratory, mass-balance study showed that there were no effects of feeding levels (1.3, 1.5 or 1....../nitrogen. Results from the commercially operated, nitrifying biofilter showed that urea-N was removed at a rate of 0.014 g N m2 day−1. Compared to the removal of TAN (0.208 g N m2 day−1), the moving bed biofilter was 1.07 times more active in removing dissolved N than immediately expected when only considering TAN...

  9. Milk Urea Dynamics during its Transformation into Yogurt

    Directory of Open Access Journals (Sweden)

    Cornelia Vintila

    2011-10-01

    Full Text Available The purpose of our work was to evaluate in what measure milk urea concentration stays in processed yogurt and in what measure urea dose influences its quality. We added known amounts of urea into milk destined to yogurt processing in order to obtain probes with concentrations from 0,5 to 28 mg/ 100 ml milk. Obtained results lead us to the conclusion that milk urea decreases dramatically until the finishing of the process of milk coagulation and its transformation into yogurt. All probes which contained higher amounts of urea than 6 mg/ 100 ml milk, urea totally disappeared from yogurt before 48 hours of keeping. Milk coagulation time and its transformation to yogurt is reduced proportional with urea concentration in milk.

  10. Site-selective 13C labeling of proteins using erythrose

    International Nuclear Information System (INIS)

    Weininger, Ulrich

    2017-01-01

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with 13 C and/or 1 H, which is achieved in the most general way by using site-selectively 13 C-enriched glucose (1- and 2- 13 C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively 13 C-enriched erythrose (1-, 2-, 3- and 4- 13 C) as a suitable precursor for 13 C labeled aromatic side chains. We quantify 13 C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the 13 C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated 13 C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective 13 C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  11. Synthesis and characterization of "1"3C_3-tristearin

    International Nuclear Information System (INIS)

    Wu Hangyu; Lin Lin; Li Lei; Chen Dazhou

    2011-01-01

    A highly efficient synthesis of "1"3C_3 labeled triglycerides of stearic acids from "1"3C_3-glycerol and stearic acids, by immobilized lipase-catalyzed in solvent-free medium was described. The structure of the product were characterized by fourier transform infrared spectrum (FT-IR), nuclear magnetic resonance (NMR), mass spectra (MS). The results showed that triglycerides of stearic acids contained three "1"3C atoms. The isotope abundance of "1"3C_3-tristearin was more than 99% and the yield was 80% of "1"3C_3-tristearin through calculation. Chemical purity (> 98%) was obtained by differential scanning calorimetry (DSC). (authors)

  12. Treating agent for urea containing radioactive materials

    International Nuclear Information System (INIS)

    Ogawa, Hiroshi; Maki, Kentaro.

    1973-01-01

    Object: To add a coagulant into urea containing radioactive material to precipitate and remove the radioactive material in the urea. Structure: Iodosalt is added into urea and next, a mixed reagent in which silver ion or silver acetic ion and iron hydroxide precipitation or ferrite ion coexist is added therein. The urea is treated to have a sufficient alkaline, after which it is introduced into a basket type centrifuge formed with a filter layer in combination of an upper glass fiber layer and a lower active carbon layer. The treating agent can uniformly remove radioactive ion and radioactive chelate within urea containing inorganic salt and various metabolites. (Nakamura, S.)

  13. Investigation of some urea derivatives under in vitro conditions

    Energy Technology Data Exchange (ETDEWEB)

    Goersch, R; Bergner, H [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

    1978-10-01

    The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The /sup 35/S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH/sub 3/ level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals.

  14. Investigation of some urea derivatives under in vitro conditions

    International Nuclear Information System (INIS)

    Goersch, R.; Bergner, H.

    1978-01-01

    The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The 35 S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH 3 level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals. (author)

  15. Carcass and meat traits, and non-carcass components of lambs fed ration containing increasing levels of urea

    Directory of Open Access Journals (Sweden)

    Sandra Rozanski

    2017-06-01

    Full Text Available The objective of this study was to evaluate the carcass and meat traits, and the non-carcass components of crossbred Dorper lambs fed diets with increasing levels of urea (0.0, 0.5, 1.0, and 1.5% of dry matter – DM. The experimental design was completely randomized with four treatments (urea inclusion levels and six replicates per treatment. Lambs were fed ad libitum for 56 days and slaughtered at 37.9 ± 5.1 kg of body weight (BW. The weight and yield of carcass before and after cooling were not influenced by urea levels, with average values of 16.9 kg and 44.6% for cold carcass weight and yield. Urea levels did not affect the morphometric measurements, the fat deposition on the carcass, the weight of carcass cuts and the weight of non-carcass components. There was a quadratic effect of urea levels on the loin yield, which may achieve maximum value of 11.31% with the inclusion of 0.84% DM urea in the feed. The pH and the color coordinates L* (brightness, a* (red intensity and C* (saturation of the meat also showed quadratic response to the urea levels, where in the minimum value of 5.53 for pH, maximum value of 48.67 for L* and minimum values of 14.04 and 16.21 for a* and C* may be obtained by including 0.53 to 0.70% DM urea in the ration. The inclusion of 0.84% DM urea in the ration is recommended to obtain maximum yield of loin and meat with attractive characteristics to the consumer, which is characterized by high red intensity and brightness. If consumers have preference for lamb meat with a more intense red color, the inclusion of 1.5% DM urea should be considered in the ration formulation.

  16. The effect of saturation magnetization of nanocatalyst and oscillating magnetic field for green urea synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Noorhana, E-mail: noorhana_yahya@petronas.com.my; Alqasem, Bilal, E-mail: bilalalqasem@yahoo.com; Irfan, Muhammad; Qureshi, Saima; Rehman, Zia Ur; Shafie, Afza; Soleimani, Hassan

    2017-02-15

    Hematite and cupric oxide nanowires have been synthesized using the oxidation method for green urea production. Hematite nanowires were obtained by the oxidation of an iron wire at a temperature of 650 °C and ambient pressure in the presence of N{sub 2} and O{sub 2} gases. Cupric oxide nanowires were obtained by the same method at 700 °C, using a copper wire. The X-ray diffraction results show the formation of rhombohedral structure of α-Fe{sub 2}O{sub 3} and monoclinic phase of CuO. FE-SEM results reveal the formation of nanowires with dimensions ranging between 5–15 µm and 4–12 µm in length and a diametere ranging between 50–150 nm and 50–250 nm for α-Fe{sub 2}O{sub 3} and CuO respectively. The VSM results show that the saturation magnetization values for hematite and cupric oxide were 132.8700 and 0.0124 emu/g, respectively. The nanowires were used as catalyst for green urea synthesis in the presence of an oscillating and a static magnetic fields. The use of nanocatalyst with high saturation magnetization gives a higher yield of urea due to the increase in the singlet to triplet conversion. The highest yield of urea 11243 ppm was achieved by applying an oscillating magnetic field of frequency 0.5 MHz and using α-Fe{sub 2}O{sub 3} nanowires as nanocatalyst. - Highlights: • Effect of saturation magnetization of nanocatalyst on urea yield was investigated • Using nanocatalyst with high saturation magnetization value improved urea yield. • Effect of oscillating magnetic field frequency on the urea yield was investigated. • The highest urea yield was achieved by applying 0.5 MHz oscillating magnetic field.

  17. The effect of saturation magnetization of nanocatalyst and oscillating magnetic field for green urea synthesis

    International Nuclear Information System (INIS)

    Yahya, Noorhana; Alqasem, Bilal; Irfan, Muhammad; Qureshi, Saima; Rehman, Zia Ur; Shafie, Afza; Soleimani, Hassan

    2017-01-01

    Hematite and cupric oxide nanowires have been synthesized using the oxidation method for green urea production. Hematite nanowires were obtained by the oxidation of an iron wire at a temperature of 650 °C and ambient pressure in the presence of N 2 and O 2 gases. Cupric oxide nanowires were obtained by the same method at 700 °C, using a copper wire. The X-ray diffraction results show the formation of rhombohedral structure of α-Fe 2 O 3 and monoclinic phase of CuO. FE-SEM results reveal the formation of nanowires with dimensions ranging between 5–15 µm and 4–12 µm in length and a diametere ranging between 50–150 nm and 50–250 nm for α-Fe 2 O 3 and CuO respectively. The VSM results show that the saturation magnetization values for hematite and cupric oxide were 132.8700 and 0.0124 emu/g, respectively. The nanowires were used as catalyst for green urea synthesis in the presence of an oscillating and a static magnetic fields. The use of nanocatalyst with high saturation magnetization gives a higher yield of urea due to the increase in the singlet to triplet conversion. The highest yield of urea 11243 ppm was achieved by applying an oscillating magnetic field of frequency 0.5 MHz and using α-Fe 2 O 3 nanowires as nanocatalyst. - Highlights: • Effect of saturation magnetization of nanocatalyst on urea yield was investigated • Using nanocatalyst with high saturation magnetization value improved urea yield. • Effect of oscillating magnetic field frequency on the urea yield was investigated. • The highest urea yield was achieved by applying 0.5 MHz oscillating magnetic field.

  18. National Urea Cycle Disorders Foundation

    Science.gov (United States)

    ... urea cycle disorders. Donate Now To End Urea Cycle Disorders © 2005-2017 NUCDF. All rights reserved. This site may be freely linked to but not copied or duplicated in any fashion without the Foundation's consent. Make A Donation in ...

  19. 13C and 31P NMR study of gluconeogenesis: utilization of 13C-labeled substrates by perfused liver from streptozotocin-diabetic and untreated rats

    International Nuclear Information System (INIS)

    Cohen, S.M.

    1987-01-01

    The metabolism of 13 C-labeled substrates was followed by 13 C and 31 P NMR in perfused liver from the streptozotocin-treated rat model of insulin-dependent diabetes. Comparison was made with perfused liver from untreated littermates, fasted either 24 or 12 h. The major routes of pyruvate metabolism were followed by a 13 C NMR approach that provided for the determination of the metabolic fate of several substances simultaneously. The rate of gluconeogenesis was 2-4-fold greater and β-hydroxybutyrate production was 50% greater in liver from the chronically diabetic rats as compared with the control groups. Large differences in the distribution of 13 C label in hepatic alanine were measured between diabetic and control groups. The biosyntheses of 13 C-labeled glutathione and N-carbamoylaspartate were monitored in time-resolved 13 C NMR spectra of perfused liver. Assignments for the resonances of glutathione and N-carbamoylaspartate were made with the aid of 13 C NMR studies of perchloric acid extracts of the freeze-clamped livers. 13 C NMR spectroscopy of the perfusates provided a convenient, rapid assay of the rate of oxidation of [2- 13 C]ethanol, the hepatic output of [2- 13 ]acetaldehyde, and the accumulation of [2- 13 C]acetate in the perfusate. By 31 P NMR spectroscopy, carbamoyl phosphate was measured in all diabetic livers and an unusual P,P'-diesterified pyrophosphate was observed in one-fourth of the diabetic livers examined. Neither of these phosphorylated metabolites was detected in control liver. Both 13 C and 31 P NMR were useful in defining changes in hepatic metabolism in experimental diabetes

  20. Relación entre la proporción áurea y el índice facial en estudiantes de Estomatología de La Habana

    Directory of Open Access Journals (Sweden)

    Alberto E Companioni Bachá

    2010-03-01

    Full Text Available La proporción áurea ha sido utilizada en el diagnóstico ortodóncico como una variable importante para decidir el tratamiento de elección. Objetivo: evaluar la relación entre la presencia de la proporción divina y el tipo facial morfológico. Métodos: se realizó un estudio descriptivo en 70 estudiantes de la Facultad de Estomatología de La Habana. Se comparó el tipo facial encontrado, con la presencia o no de la divina proporción (1,618 entre la altura de la cabeza y la anchura bicigomática. Resultados: los tipos faciales euriprosopo y mesoprosopo fueron los más representados (38,57 % cada uno. El 65,71 % del total presentó la proporción áurea. En ambos sexos predominaron los que tuvieron la proporción (femenino con 66,67 %, masculino con 64 %, al igual que el 74,07 % de los mesoprosopos y el 62,96 % de los euriprosopos. En el sexo femenino los tres tipos faciales cumplieron significativamente (p< 0,05 con la proporción y en el masculino solo los mesoprosopos con un 80,00 %. Conclusiones: los tipos faciales euriprosopo y mesoprosopo constituyeron la mayoría de la muestra estudiada, predominaron los estudiantes con la divina proporción en las mediciones estudiadas, en el sexo masculino sobresale en los mesoprosopos ganando en estos, mayor significación diagnóstica.

  1. Urea concentration in sheep’s milk

    Directory of Open Access Journals (Sweden)

    Jasmina Havranek

    2009-03-01

    Full Text Available Determining urea concentration in milk is a useful indicator for controlling supply of proteins to organisms, as well as the relationship of energy and protein in the food, thus it is finding more and more ways of practical use. The concentration of urea in milk, along with the feeding process, is influenced by a number of other factors such as: breed, stage and sequence of lactation, body mass, daily production and chemical structure of milk, number of somatic cells, season, milking.The goal of the research was to establish the influence of the breed (Island of Krk, East Frisian, lactation stage (beginning, middle and the end and the herd (3 to the concentration of urea in milk during lactation.For each breed there has been established daily quantity of milk, protein share and the concentration of urea in milk.Statistical analysis of data was conducted by using General Linear Models procedure, SAS program system (1999.The breed of sheep considerably (P<0.001 influenced daily quantity of milk, protein share and the concentration of urea in the milk.East Frisian sheep produced on average almost double the daily quantities of milk (1070 mL compared to the Krk sheep (588 mL.Protein share and the urea concentration in Krk sheep milk were higher (5.99 % and 35.97 mg/100 mL then in the milk of East Frisian sheep (5.12 % and 33.31 mg/100 mL.For both breeds the significant influence of lactation stage to the daily milk quantity has been established (0.001, that is also for the urea concentration in the milk of Krk sheep (0.001, as well as protein share in the milk of East Frisian sheep (0.001.Herd influence significantly affected daily milk quantities (0.001 and concentration of urea in the milk (0.05.The defining of the urea concentration in sheep milk should be occasionally carried out in the Republic of Croatia to establish the standard physiological values typical for the particular sheep breed.

  2. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene urea...

  3. The 13C bicarbonate method

    DEFF Research Database (Denmark)

    Junghans, Peter; Larsson, Caroline; Jensen, Rasmus Bovbjerg

    2015-01-01

    2 production calculated by the (13)C-BM, RaCO2((13)C) is compared to the result from the indirect calorimetry, RCO2(IC). In an interspecies comparison (dog, goat, horse, cattle, children, adult human; body mass ranging from 15 to 350 kg, resting and fasting conditions) we found an excellent...

  4. Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk

    International Nuclear Information System (INIS)

    Banchorndhevakul, Siriwattana

    2002-01-01

    Cellulose degradation of 20% urea treated and 20% urea-10 kGy gamma treated Thai rice straw and corn stalk showed that combination effect of urea and gamma radiation gave a higher % decrease in neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, and lignin and cutin in comparison with urea effect only for both room temperature storage and room temperature +258 K storage. The results also indicated that cellulose degradation proceeded with time, even at 258 K. A drastic drop to less than half of the original contents in NDF, ADF, and ADL could not be obtained in this study

  5. Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk

    Science.gov (United States)

    Banchorndhevakul, Siriwattana

    2002-08-01

    Cellulose degradation of 20% urea treated and 20% urea-10 kGy gamma treated Thai rice straw and corn stalk showed that combination effect of urea and gamma radiation gave a higher % decrease in neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, and lignin and cutin in comparison with urea effect only for both room temperature storage and room temperature +258 K storage. The results also indicated that cellulose degradation proceeded with time, even at 258 K. A drastic drop to less than half of the original contents in NDF, ADF, and ADL could not be obtained in this study.

  6. Respuesta de Physalis peruviana a la fertilización con diferentes dosis de N, P y K en el Altiplano de Pasto, Colombia

    Directory of Open Access Journals (Sweden)

    Amanda Silva Parra

    2015-10-01

    Full Text Available En un Andisol Typic dystrandept del Altiplano de Pasto (2800 m.s.n.m., 12.6°C, 820 mm/año y 900 h de luz solar, Colombia, se evaluaron algunas variables de crecimiento, contenido de nutrientes y producción de uvilla (Physalis peruviana como respuesta a la fertilización con N, P y K. Los tratamientos consistieron en la aplicación de urea (46% N como fuente de N, superfosfato triple-SPT (46% de P2O5 como fuente de P y cloruro de potasio-KCl (60% K2O como fuente de K, en dosis iguales para cada fuente, de 80, 150 y 300 kg/ha/año aplicados en dos épocas al momento del trasplante y 30 días después, antes de la floración. Los resultados mostraron diferencias en fuentes y dosis (P ≤ 0.01 en todas las variables analizadas. Las dosis de 300 kg/ha de urea, 150 kg/ha de SPT y 300 kg/ha de KCl favorecieron la mayor altura de planta, la materia seca y la absorción de NPK (P ≤ 0.05. La absorción de N fue mayor que la de K y éste a su vez que la de P en todas las interacciones evaluadas (P ≤ 0.05. La aplicación de 300 kg/ha de cada uno de los fertilizantes ocasiono incremento del rendimiento de P. peruviana. Por otra parte, fueron encontrados efectos positivos en la absorción NPK en relación con los rendimientos de Physalis peruviana con 300 kg/ha de urea, 150 kg/ha de SPT y 300 kg/ha de KCl (P ≤ 0.05, por tanto se recomiendan estas dosis de fertilizantes.

  7. The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra

    Science.gov (United States)

    Nixon, C. A.; Achterberg, R. K.; Vinatier, S.; Bézard, B.; Coustenis, A.; Irwin, P. G. J.; Teanby, N. A.; de Kok, R.; Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Flasar, F. M.

    2008-06-01

    We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12C/ 13C in any C 2 molecule on Titan, and the first measurement of 12CH 4/ 13CH 4 (non-deuterated) on Titan by remote sensing. Our spectra cover five widely-spaced latitudes, 65° S to 71° N and we have searched for both latitude variability of 12C/ 13C within a given species, and also for differences between the 12C/ 13C in the three gases. For CH 4 alone, we find C12/C13=76.6±2.7 (1- σ), essentially in agreement with the 12CH 4/ 13CH 4 measured by the Huygens Gas Chromatograph/Mass Spectrometer instrument (GCMS) [Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784]: 82.3±1.0, and also with measured values in H 13CN and 13CH 3D by CIRS at lower precision [Bézard, B., Nixon, C., Kleiner, I., Jennings, D., 2007. Icarus 191, 397-400; Vinatier, S., Bézard, B., Nixon, C., 2007. Icarus 191, 712-721]. For the C 2 species, we find C12/C13=84.8±3.2 in C 2H 2 and 89.8±7.3 in C 2H 6, a possible trend of increasingly value with molecular mass, although these values are both compatible with the Huygens GCMS value to within error bars. There are no convincing trends in latitude. Combining all fifteen measurements, we obtain a value of C12/C13=80.8±2.0, also compatible with GCMS. Therefore, the evidence is mounting that 12C/ 13C is some 8% lower on Titan than on the Earth (88.9, inorganic standard), and lower than typical for the outer planets ( 88±7 [Sada, P.V., McCabe, G.H., Bjoraker, G.L., Jennings, D.E., Reuter, D.C., 1996. Astrophys. J. 472, 903-907]). There is no current model for this enrichment, and we discuss several mechanisms that may be at work.

  8. 21 CFR 862.1770 - Urea nitrogen test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

  9. Porous Cross-Linked Polyimide-Urea Networks

    Science.gov (United States)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor)

    2015-01-01

    Porous cross-linked polyimide-urea networks are provided. The networks comprise a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage. The oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units. The subunit was formed by reaction of the diamine and a diisocyanate to form a diamine-urea linkage-diamine group, followed by reaction of the diamine-urea linkage-diamine group with the dianhydride and the diamine to form the subunit. The subunit has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups. The subunit has been chemically imidized to yield the porous cross-linked polyimide-urea network. Also provided are wet gels, aerogels, and thin films comprising the networks, and methods of making the networks.

  10. CACA-TOCSY with alternate {sup 13}C-{sup 12}C labeling: a {sup 13}C{sup {alpha}} direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Koh [National Institute of Advanced Industrial Science and Technology (AIST), Biomedicinal Information Research Center (BIRC) (Japan); Frueh, Dominique P.; Sun, Zhen-Yu J.; Hiller, Sebastian; Wagner, Gerhard, E-mail: gerhard_wagner@hms.harvard.ed [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States)

    2010-05-15

    We present a {sup 13}C direct detection CACA-TOCSY experiment for samples with alternate {sup 13}C-{sup 12}C labeling. It provides inter-residue correlations between {sup 13}C{sup {alpha}} resonances of residue i and adjacent C{sup {alpha}s} at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C{sup {alpha}} nuclei separated by more than one residue. The experiment also provides C{sup {alpha}}-to-side chain correlations, some amino acid type identifications and estimates for {psi} dihedral angles. The power of the experiment derives from the alternate {sup 13}C-{sup 12}C labeling with [1,3-{sup 13}C] glycerol or [2-{sup 13}C] glycerol, which allows utilizing the small scalar {sup 3}J{sub CC} couplings that are masked by strong {sup 1}J{sub CC} couplings in uniformly {sup 13}C labeled samples.

  11. 13C separation by IRMPD of halogenated difluoromethanes

    International Nuclear Information System (INIS)

    Ma Peihua; Chen Guancheng; Wu Bin; Liu Julin; Jing Yan; Chu Minxiong; Arai, Shigeyoshi.

    1995-01-01

    Isotopically-selective consecutive two-stage infrared multiphoton dissociation (IRMPD) of halogenated difluoromethanes in the presence of scavengers produces carbon-13 over 95 %. The reaction mechanism for the IRMPD of mixture of CHClF 2 and HI can be explained by a series of first-order dissociation reactions and followed radical-scavenger reactions occurred in a continuous irradiation procedure. Furthermore, 13 C enrichment at laboratory scaling-up level by the 13 C selective IRMPD of CHClF 2 /Br 2 mixture has been investigated in a flow reactor. The 13 C production rates, 13 C atomic fractions in the CBr 2 F 2 products and 13 C depletions in the CHClF 2 reactants at different flow rates and laser repetition frequencies were examined to optimize the parameters suitable for large-scale production of carbon isotope. The data obtained from the flow tests demonstrated a 40 mg h -1 production rate for CB 2 F 2 at 65 % carbon-13 by using a 40 W (4J, 10 Hz) laser beam focused with a lens of focal length 120 cm. If a reliable TEA CO 2 laser can be operated with 100 W (10 J, 10 Hz) output, the production rate of CBr 2 F 2 for carbon-13 at 60 % can attain 200 mg h -1 . The measurements of spatial profile of focused laser beam imply a 2 g h -1 production rate for the 60 % carbon-13 product for an incident power of 200 W (20 J, 10 Hz). (author)

  12. Experiencia en reconstrucción auricular en cáncer de piel con colgajo en "quesadilla"

    Directory of Open Access Journals (Sweden)

    C. Gutiérrez Gómez

    Full Text Available La reconstrucción auricular es una de las más difíciles ya que implica reproducir las sofisticadas y delicadas formas del pabellón auricular. Cuando hay que resecar piel en la oreja por un cáncer cutáneo y dejamos expuesto el cartílago, sin pericondrio, suele suceder que al colocar injertos no hay una integración adecuada de los mismos por las caprichosas formas y relieves del pabellón auricular; cuando es necesario resecar el pericondrio estamos obligados a cubrir el defecto con un colgajo y no con un simple injerto. Frente a esta dificultad técnica, diseñamos un colgajo ricamente vascularizado que preserva el cartílago no afectado con una buena cubierta y al mismo tiempo respeta la anatomía de la oreja. Para la cobertura del cartílago auricular anterior usamos un colgajo fasciocutáneo posterior que se asemeja a un plato típico de la cocina mexicana que llamamos "quesadilla", donde el cartílago por su color blanco recuerda el queso y el gran colgajo fasciocutaneo recuerda la tortilla que cubre al queso. Este colgajo incluye la piel enrollada del hélix, que en un segundo tiempo retornará a su lugar de origen anatómico mediante una z-plastía asimétrica. Presentamos, de entre una serie de 13 pacientes con carcinoma de pabellón auricular, 2 casos resueltos mediante esta técnica.

  13. Foliar fertilization of sugarcane (Saccharum spp): absorption and translocation of 15-N-labeled urea

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Carvalho, J.G. de; Silva, A.Q. da; Primavesi, A.C.P.A.; Camacho, E.; Eimori, I.E.; Guilherme, M.R.

    1988-01-01

    The absorption and translocation of foliar applied nitrogen as urea solution to sugar cane plants was evaluated. An experiment using the isotope dilution technique with 15 N labeled urea was carried out in green house condition. Seedlings of sugarcane variety IAC 53-150 were planted in pots with 5KG of top soil''latossolo vermelho amarelo, fase arenosa'' (Haplustox). (M.A.C.) [pt

  14. 26 CFR 1.381(c)(13)-1 - Involuntary conversions.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Involuntary conversions. 1.381(c)(13)-1 Section 1.381(c)(13)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Insolvency Reorganizations § 1.381(c)(13)-1 Involuntary conversions...

  15. Funcionalidad de las relaciones intrafamiliares en los pacientes con cáncer

    Directory of Open Access Journals (Sweden)

    Jairzinho Granados-Villamil

    2014-06-01

    Full Text Available Objetivo: medir el nivel de funcionalidad de las relaciones intrafamiliares del núcleo familiar de los pacientes con cáncer, inscritos en un programa de lucha contra el cáncer. Materiales y Métodos: estudio descriptivo, de corte transversal con un abordaje cuantitativo. La población objeto de estudio son 165 pacientes, 83 pacientes y 82 cuidadores que corresponden al total de pacientes y su cuidador. Para recolectar la información se aplicó el instrumento evaluación de las relaciones intrafamiliares (ERI en entrevista directa a los pacientes de oncología y su cuidador, diseñado por Rivera y Andrade (1, que evalúa las escalas expresión dificultades y la escala unión y apoyo. Resultados: en la escala de expresión prevalece el nivel alto con un 36%, en la escala de dificultades se observó que el nivel medio obtuvo 39% la escala de unión y apoyo en general mostro que existe prevalencia en el nivel alto un 46%. Conclusiones: los pacientes y las familias, en general, creen que pueden expresar abiertamente sus emociones, inquietudes o problemas, asumiendo la certeza de ser escuchado y comprendido. En los entornos familiares, la convivencia, la tolerancia, la paciencia y la comprensión no satisfacen el alto nivel de estrés y la complejidad de ser pacientes con cáncer lo cual suele alterar completamente la estructura de la rutina y de la familia.

  16. Inhibitors of the alpha-ketoglutarate dehydrogenase complex alter [1-13C]glucose and [U-13C]glutamate metabolism in cerebellar granule neurons.

    Science.gov (United States)

    Santos, Sónia Sá; Gibson, Gary E; Cooper, Arthur J L; Denton, Travis T; Thompson, Charles M; Bunik, Victoria I; Alves, Paula M; Sonnewald, Ursula

    2006-02-15

    Diminished activity of the alpha-ketoglutarate dehydrogenase complex (KGDHC), an important component of the tricarboxylic acid (TCA) cycle, occurs in several neurological diseases. The effect of specific KGDHC inhibitors [phosphonoethyl ester of succinyl phosphonate (PESP) and the carboxy ethyl ester of succinyl phosphonate (CESP)] on [1-13C]glucose and [U-13C]glutamate metabolism in intact cerebellar granule neurons was investigated. Both inhibitors decreased formation of [4-13C]glutamate from [1-13C]glucose, a reduction in label in glutamate derived from [1-13C]glucose/[U-13C]glutamate through a second turn of the TCA cycle and a decline in the amounts of gamma-aminobutyric acid (GABA), aspartate, and alanine. PESP decreased formation of [U-13C]aspartate and total glutathione, whereas CESP decreased concentrations of valine and leucine. The findings are consistent with decreased KGDHC activity; increased alpha-ketoglutarate formation; increased transamination of alpha-ketoglutarate with valine, leucine, and GABA; and new equilibrium position of the aspartate aminotransferase reaction. Overall, the findings also suggest that some carbon derived from alpha-ketoglutarate may bypass the block in the TCA cycle at KGDHC by means of the GABA shunt and/or conversion of valine to succinate. The results suggest the potential of succinyl phosphonate esters for modeling the biochemical and pathophysiological consequences of reduced KGDHC activity in brain diseases.

  17. Evaluación de ensilajes mixtos de Saccharum officinarum y Gliricidia sepium con la utilización de aditivos Evaluation of mixed silages of Saccharum officinarum and Gliricidia sepium using additives

    Directory of Open Access Journals (Sweden)

    R Suárez

    2011-03-01

    Full Text Available Se realizó un experimento en Trujillo, Venezuela, con el objetivo de evaluar el efecto de la adición de melaza y urea en ensilajes de cogollo quemado de caña de azúcar y Gliricidia sepium, utilizando macrobolsas de 1,18 m³ de capacidad y vacío, mediante un diseño factorial 4 (tipo de ensilaje x 3 (tiempo de fermentación: 20, 40 y 60 días y cinco réplicas. Los tratamientos fueron T1 (cogollo de caña de azúcar, 75% más G. sepium, 25%; T2 (T1 más urea, 0,5%; T3 (T1 más melaza, 4% y T4 (T3 más urea, 0,5%. Se determinó el pH, la MS, la PB, el amoníaco, el nitrógeno soluble, la FB, el extracto libre de nitrógeno, el extracto etéreo, el Ca, el P y la ceniza. No hubo interacción tipo de ensilaje por tiempo de fermentación. Con la adición de urea (T2 se observaron los mayores valores de pH (5,03, PB (8,27%, NH3/Nt (18,13% y NS/Nt (38,31%. Al adicionar la melaza (T3 se constató un mayor porcentaje de MS (35,34 y de ELN (50,93, y con los dos aditivos (T4 se observó un menor contenido de EE (1,02%. Los tenores de FB, los minerales y la ceniza no presentaron diferencias entre los tratamientos. A los 40 días de fermentación se observó un mayor contenido de MS (44,80% y ELN (49,72%. Sin embargo, a los 60 días se obtuvo mayor relación NH3/Nt (11,17% y NS/Nt (33,61%. Mediante la ponderación de las variables más relevantes se concluyó que los ensilajes de mayor calidad se obtuvieron cuando sólo se adicionó melaza (4% o se combinó con urea (0,5%; mientras que la calidad del material conservado fue menor a los 60 días de elaboración.A trial was conducted in Trujillo, Venezuela, in order to evaluate the effect of the addition of molasses and urea in silages of burnt sugarcane tops and Gliricidia sepium, using macrobags of capacity 1,18 m³ and vacuum, by means of a 4 (type of silage x 3 (fermentation time: 20, 40 and 60 days factorial arrangement and five replications. The treatments were T1 (sugarcane tops, 75% plus G. sepium

  18. Synthesis of ring-13C-labelled and ring-demethylated retinals

    International Nuclear Information System (INIS)

    Courtin, J.M.L.

    1988-01-01

    Efficient synthetic schemes are described for the preparation of the required mono- and di- 13 C labelled retinals based on simple 13 C labelled starting materials. Results from solid-state 13 C-NMR spectroscopic studies of the various ring- 13 C labelled bacteriorhodopsins and rhodopsins are discussed. 404 refs.; 74 figs.; 16 tabs

  19. Na,K-ATPase structure/function relationships probed by the denaturant urea.

    Science.gov (United States)

    Esmann, Mikael; Fedosova, Natalya U; Olesen, Claus

    2015-05-01

    Urea interacts with the Na,K-ATPase, leading to reversible as well as irreversible inhibition of the hydrolytic activity. The enzyme purified from shark rectal glands is more sensitive to urea than Na,K-ATPase purified from pig kidney. An immediate and reversible inhibition under steady-state conditions of hydrolytic activity at 37°C is demonstrated for the three reactions studied: the overall Na,K-ATPase activity, the Na-ATPase activity observed in the absence of K+ as well as the K+-dependent phosphatase reaction (K-pNPPase) seen in the absence of Na+. Half-maximal inhibition is seen with about 1M urea for shark enzyme and about 2M urea for pig enzyme. In the presence of substrates there is also an irreversible inhibition in addition to the reversible process, and we show that ATP protects against the irreversible inhibition for both the Na,K-ATPase and Na-ATPase reaction, whereas the substrate paranitrophenylphosphate leads to a slight increase in the rate of irreversible inhibition of the K-pNPPase. The rate of the irreversible inactivation in the absence of substrates is much more rapid for shark enzyme than for pig enzyme. The larger number of potentially urea-sensitive hydrogen bonds in shark enzyme compared to pig enzyme suggests that interference with the extensive hydrogen bonding network might account for the higher urea sensitivity of shark enzyme. The reversible inactivation is interpreted in terms of domain interactions and domain accessibilities using as templates the available crystal structures of Na,K-ATPase. It is suggested that a few interdomain hydrogen bonds are those mainly affected by urea during reversible inactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Tailoring of analytical performances of urea biosensors using nanomaterials

    International Nuclear Information System (INIS)

    Nouira, W; Barhoumi, H; Maaref, A; Renault, N Jaffrézic; Siadat, M

    2013-01-01

    This paper is a contribution to the study of enzymatic sensors based on nanoparticles of iron oxide (FeNPs). Urease enzyme was immobilized on FeNPs using layer-by-layer (LbL) deposition method. FeNPs were first coated with polyelectrolytes (PE): Poly (allylamine hydrochloride), PAH and Poly (sodium 4-styrenesulfonate), PSS for enzyme immobilization and then with enzyme. It has been confirmed through zeta potential measurements of FeNPs that the enzyme is immobilized on the surface. We evaluated the sensitivity of biosensors for urea by potentiometric and capacitive measurements on silicon / silica / FeNP-LBL-urease structures. The recorded capacity-potential curves (C-V) show a significant shift of flat band potential towards negative potentials in the presence of urea, the observed values of sensitivity vary between 30 and 40 mV/p[urea]. It has been shown that the proposed method for the immobilization of urease can increase the dynamic range of urea detection (10 −4 M to 10 −1 M) compared to the immobilization of urease without FeNP (10 −3.5 M to 10 −2.5 M). When the number of PAH-PSS layers was increased the sensitivity of detection was modified. This effect is due to partial inhibition of the enzyme in presence of FeNPs, which was shown by measurements in homogeneous phase.

  1. Correlación entre índice de catabolismo proteico medido por el modelo cinético de la urea y la encuesta dietética en niños con insuficiencia renal crónica en diálisis.

    Directory of Open Access Journals (Sweden)

    Susan CORNEJO FLORES

    2006-04-01

    Full Text Available Objetivo: Determinar la correlación entre ICP calculado por el modelo cinético de urea y la ingesta proteica determinada mediante encuesta dietética. Material y métodos: En el estudio analítico de correlación, se incluyeron 15 niños con insuficiencia renal crónica (IRC evaluados en un periodo de un año de seguimiento. Se determinó el ICP mediante la encuesta de Frecuencia de Consumo y recordatorio de 24 h por 3 días y el modelo cinético de la úrea, al inicio y al final del estudio. Se determinó albúmina sérica, urea sérica pre y post recolección de orina en el periodo ínterdialítico y urea en orina del periodo interdialítico. Resultados. El 46,67%(7 fueron del sexo femenino y 53,33%(8 masculino. La edad fue 15 ±2 años. Al inicio, 20% de los pacientes tuvieron niveles de albúmina sérica normales y al final del estudio fue 86,67%. El promedio del ICP calculado al inicio fue 0,993±0,27 y 0,996 ± 0,28 por modelo cinético y encuesta dietética respectivamente y su correlación fue r = 0,9962 y R²= 0,9924. Al final del estudio fue 1,07± 0,28 calculado por la encuesta y de 1,06± 0,27 por el modelo cinético de generación de urea y su correlación fue de r =0,9973 y R²= 0,9924. Conclusión: Existe buena correlación entre el ICP calculado por el modelo cinético de generación de urea y la ingesta proteica determinada por la encuesta dietética (Rev Med Hered 2006;17:77-80.

  2. 14C-urea breath test in the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Artiko, V.M.; Obradovic, V.B.; Petrovic, N.S.; Davidovic, B.M.; Grujic-Adanja, G.S.; Nastic-Miric, D.R.; Milosavljevic, T.N.

    2001-01-01

    Helicobacter pylori infection is supposed to be one of the major causes of digestive and other diseases. Among a lot of invasive and non-invasive methods for its detection, none is ideal. The aim is an assessment of the Helicobacter pylori infection in the stomach using breath test and comparison to other diagnostic methods, as well as following up the effects of therapy. In 17 patients with digestive discomfort, breath test, rapid urease test and histology were performed, while in 47 patients with proven HP infection the effect of therapy was followed up using breath test and clinical findings. Breath test was performed after per oral administration of the capsule of 14 C urea (37 kBq). Findings of the breath and urease tests were in accordance in 14/17 patients (83%) while breath test and histology in 16/17 patients (94%). During follow-up of the therapeutic effects, breath test and clinical findings were in accordance in 43/47 patients (98%). Breath test can be useful in diagnosis but is a method of choice in following up the patients after therapy for H. pylori infection, because it is non-invasive, fast and precise. (author)

  3. [2,4-(13)C]β-hydroxybutyrate metabolism in astrocytes and C6 glioblastoma cells.

    Science.gov (United States)

    Eloqayli, Haytham; Melø, Torun M; Haukvik, Anne; Sonnewald, Ursula

    2011-08-01

    This study was undertaken to determine if the ketogenic diet could be useful for glioblastoma patients. The hypothesis tested was whether glioblastoma cells can metabolize ketone bodies. Cerebellar astrocytes and C6 glioblastoma cells were incubated in glutamine and serum free medium containing [2,4-(13)C]β-hydroxybutyrate (BHB) with and without glucose. Furthermore, C6 cells were incubated with [1-(13)C]glucose in the presence and absence of BHB. Cell extracts were analyzed by mass spectrometry and media by (1)H magnetic resonance spectroscopy and HPLC. Using [2,4-(13)C]BHB and [1-(13)C]glucose it could be shown that C6 cells, in analogy to astrocytes, had efficient mitochondrial activity, evidenced by (13)C labeling of glutamate, glutamine and aspartate. However, in the presence of glucose, astrocytes were able to produce and release glutamine, whereas this was not accomplished by the C6 cells, suggesting lack of anaplerosis in the latter. We hypothesize that glioblastoma cells kill neurons by not supplying the necessary glutamine, and by releasing glutamate.

  4. Biokinetics and radiation dosimetry of {sup 14}C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, Mikael

    2002-08-01

    {sup 14}C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used {sup 14}C-breath tests: {sup 14}C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low {sup 14}C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform {sup 14}C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of {sup 14}C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: {sup 14}C-glycocholic acid - 0.4 mSv/MBq, {sup 14}C-triolein - 0.3 mSv/MBq, {sup 14}C-xylose - 0.1 mSv/MBq and {sup 14}C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the {sup 14}C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  5. CACA-TOCSY with alternate 13C-12C labeling: a 13Cα direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification

    International Nuclear Information System (INIS)

    Takeuchi, Koh; Frueh, Dominique P.; Sun, Zhen-Yu J.; Hiller, Sebastian; Wagner, Gerhard

    2010-01-01

    We present a 13 C direct detection CACA-TOCSY experiment for samples with alternate 13 C- 12 C labeling. It provides inter-residue correlations between 13 C α resonances of residue i and adjacent C α s at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C α nuclei separated by more than one residue. The experiment also provides C α -to-sidechain correlations, some amino acid type identifications and estimates for ψ dihedral angles. The power of the experiment derives from the alternate 13 C- 12 C labeling with [1,3- 13 C] glycerol or [2- 13 C] glycerol, which allows utilizing the small scalar 3 J CC couplings that are masked by strong 1 J CC couplings in uniformly 13 C labeled samples.

  6. 13C, 1H spin-spin coupling constants. Pt. 4

    International Nuclear Information System (INIS)

    Aydin, R.; Guenther, H.

    1979-01-01

    One-bond, geminal, and vicinal 13 C, 1 H coupling constants have been determined for adamantane using α-and β-[D]adamantane and the relation sup(n)J( 13 C, 1 H)=6,5144sup(n)J( 13 C, 2 H) for the conversion of the measured sup(n)J( 13 C, 2 H) values. It is shown that the magnitude of 3 Jsub(trans) is strongly influenced by the substitution pattern. Relative H,D isotope effects for 13 C chemical shifts are given. (orig.) [de

  7. Firmes continuos de hormigón armado

    Directory of Open Access Journals (Sweden)

    Taylor, I. J.

    1959-11-01

    Full Text Available Las primeras pavimentaciones de hormigón construidas en EE. UU. se realizaron utilizando bloques de hormigón de unos 55 dm2 de superficie y 0,15 m de espesor. Los primeros éxitos obtenidos con estos materiales sirvieron de aliento para ir modificando y perfeccionando estas estructuras y los métodos constructivos. En los primeros pasos se aumentó las dimensiones de los bloques y se reforzaron con armaduras para dotarlas de mayor resistencia. Los revestimientos se apoyaban en una capa granular de piedra que mejoraba el drenaje y el aislamiento.

  8. Utilization of urea-nitrogen-15 in ruminants

    International Nuclear Information System (INIS)

    Boda, K.; Varady, J.; Havassy, I.

    1976-01-01

    In Merino sheep a series of experiments were carried out investigating exogenous and endogenous urea utilization. On the experimental sheep with isolated jejunum, rumen and intestine fistula, re-entral intestine cannulae, and after intra-ruminal or intra-intestinal 15 N-urea administration it was found that urea- 15 N takes part in the nitrogen recycling, and is utilized in the nitrogen pool. In experiments with synthetic protein-free diet, low protein diet and high nitrogen diet, after the intravenous administration of 15 N-urea the following findings were made: The results of experiments with synthetic diet, where the only nitrogen source was perorally (for 3-6 months) and then intravenously (for 3 months) administered urea, indicated the ability of ruminants to replace fully the nitrogen in the feed under certain conditions by increased endogenous urea recirculation. The results of the experiments with various nitrogen intakes showed that considerable amounts of urea- 15 N (44-96% from the given dose) were retained. Nitrogen compounds synthetized from blood urea- 15 N were recycled through the alimentary tract. Its secretion predominated in the forestomachs, abomasum and duodenum, and its reabsorption took place in the intestinal tract. From the 15 N incorporated into the nitrogenous substances which passed through the duodenum, 73-84% was reabsorbed. The retained 15 N was incorporated into the microbial and plasma proteins and its amide-N. On the basis of these results it is concluded that in addition to the rumeno-hepatal circulation, the entero-hepatal circulation of nitrogenous substances, including endogenous nitrogen, also plays an important role quantitatively and perhaps qualitatively in the process of re-utilizing the blood urea N for proteosynthesis and synthesis of other N-metabolites in ruminants. The hydrolysis of endogenous urea in the gastro-intestinal tract of ruminants and its utilization is a natural process indispensable for the maintenance of

  9. Urea-assisted low temperature green synthesis of graphene nanosheets for transparent conducting film

    Science.gov (United States)

    Chamoli, Pankaj; Das, Malay K.; Kar, Kamal K.

    2018-02-01

    Present work demonstrates the fabrication of graphene nanosheet (GN) based transparent conducting film (TCF) using spray coating. Green synthesis of GN is carried out by reduction of graphene oxide (GO) using urea as green reducing agent. The reductive ability of urea with varied concentration is studied for GO at low temperature (i.e., 90 °C). As synthesized graphene nanosheets (GNs) are characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscope (AFM), and X-ray Photon spectroscopy (XPS). Raman analysis confirms that the maximum reduction of oxygen species is noticed using 30 mg/ml urea concentration at 90 °C from GO, and found Raman D to G band ratio (ID/IG) of ∼1.30. XPS analysis validates the Raman signature of removal of oxygen functional groups from GO, and obtained C/O ratio of ∼5.28. Further, transparent conducting films (TCFs) are fabricated using synthesized GNs. Thermal graphitization is carried out to enhance the optical and electrical properties of TCFs. TCF shows best performance when it is annealed at 900 °C for 1 h in vacuum, and obtained sheet resistance is ∼1.89 kΩ/□ with transmittance of ∼62.53%.

  10. A Simple and Sensitive RP-UPLC Method for the Simultaneous Determination of N-Hydroxybenzotriazole, Cinchonidine and 1,3-Dicyclohexyl Urea Contents in Fosinopril Sodium Drug Substance

    Directory of Open Access Journals (Sweden)

    M. Narendra Kumar

    2012-01-01

    Full Text Available A simple and sensitive reverse phase ultra performance liquid chromatography (RP-UPLC method has been developed, optimized and validated for the simultaneous determination of N-Hydroxybenzotriazole (HOBt, Cinchonidine and 1,3-Dicyclohexyl urea (DCU contents at low levels in fosinopril sodium drug substance. Efficient chromatographic separation was achieved on Acquity UPLC HSS C18 column, 100 mm long with 2.1 mm i.d., 1.8 µm particle diameter, thermo stated at 30°C. Gradient elution involving binary mixture of potassium dihydrogen orthophosphate (0.01M, pH:3.0±0.05 with ortho-phosphoric acid and acetonitrile at a flow rate of 0.10 mL min-1 has been used. The analytes were monitored by photodiode array (PDA detector set at 205 nm. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis, thermal and humidity degradation. The method was validated for specificity, sensitivity, linearity, precision, accuracy and solution stability. The limit of detection (LOD and limit of quantification (LOQ for HOBt, Cinchonidine and DCU were in the range of 0.85-3.52 ppm and 2.57-10.67 ppm, respectively. The average recoveries for HOBt, Cinchonidine and DCU are in the range of 98.1% to 102.6%. The method can be used for the routine quality control analysis of fosinopril sodium drug substance.

  11. Synthesis and applications of {sup 13}C glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States)

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  12. Synthetic Swan band profile of (1,0) of 12C12C and (0,0) of 12C12C and 12C13C in comets

    International Nuclear Information System (INIS)

    Swamy, K.S.K.

    1987-01-01

    The statistical equilibrium calculations of the 12 C 13 C molecule based on the resonance fluorescence process give similar results to those of the normal molecule. Therefore the assumption that the observed intensities of bands of the normal and the isotopic molecule differ only by their abundance ratio is reasonable. The synthetic profile of the (1,0) Swan band of 12 C 13 C (0,0) band of 12 C 12 C and 12 C 13 C have been calculated. The relative merits of using the rotational structure of the (1,0) or (0,0) band for the determination of the isotopic ratio 12 C/ 13 C is discussed briefly. (author)

  13. Residual effect of sugar cane ratoon of urea nitrogen foliar application to plant cane

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Lara Cabezas, W.A.R.; Coleti, J.T.

    1984-01-01

    The residual effect of urea - N, foliar applied to plant cane, on sugar cane ratoon is studied. Setts grown in drums containing washed sand are used. 180 days from planting, foliar fertilizer (43.5% urea solution) labelled with 3.95 atom % 15 N is applied. The first harvest is made 7 days after application and final harvest of resprouting at 123 days. (M.A.C.) [pt

  14. Spectroscopic and MD simulation studies on unfolding processes of mitochondrial carbonic anhydrase VA induced by urea.

    Science.gov (United States)

    Idrees, Danish; Prakash, Amresh; Haque, Md Anzarul; Islam, Asimul; Ahmad, Faizan; Hassan, Md Imtaiyaz

    2016-09-01

    Carbonic anhydrase VA (CAVA) is primarily expressed in the mitochondria and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis and neuronal transmission. To understand the biophysical properties of CAVA, we carried out a reversible urea-induced isothermal denaturation at pH 7.0 and 25°C. Spectroscopic probes, [θ]222 (mean residue ellipticity at 222 nm), F344 (Trp-fluorescence emission intensity at 344 nm) and Δε280 (difference absorption at 280 nm) were used to monitor the effect of urea on the structure and stability of CAVA. The urea-induced reversible denaturation curves were used to estimate [Formula: see text], Gibbs free energy in the absence of urea; Cm, the mid-point of the denaturation curve, i.e. molar urea concentration ([urea]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[urea]). Coincidence of normalized transition curves of all optical properties suggests that unfolding/refolding of CAVA is a two-state process. We further performed 40 ns molecular dynamics simulation of CAVA to see the dynamics at different urea concentrations. An excellent agreement was observed between in silico and in vitro studies.

  15. Urea, a true uremic toxin: the empire strikes back.

    Science.gov (United States)

    Lau, Wei Ling; Vaziri, Nosratola D

    2017-01-01

    Blood levels of urea rise with progressive decline in kidney function. Older studies examining acute urea infusion suggested that urea was well-tolerated at levels 8-10× above normal values. More recent in vitro and in vivo work argue the opposite and demonstrate both direct and indirect toxicities of urea, which probably promote the premature aging phenotype that is pervasive in chronic kidney disease (CKD). Elevated urea at concentrations typically encountered in uremic patients induces disintegration of the gut epithelial barrier, leading to translocation of bacterial toxins into the bloodstream and systemic inflammation. Urea induces apoptosis of vascular smooth muscle cells as well as endothelial dysfunction, thus directly promoting cardiovascular disease. Further, urea stimulates oxidative stress and dysfunction in adipocytes, leading to insulin resistance. Finally, there are widespread indirect effects of elevated urea as a result of the carbamylation reaction, where isocyanic acid (a product of urea catabolism) alters the structure and function of proteins in the body. Carbamylation has been linked with renal fibrosis, atherosclerosis and anaemia. In summary, urea is a re-emerging Dark Force in CKD pathophysiology. Trials examining low protein diet to minimize accumulation of urea and other toxins suggest a clinical benefit in terms of slowing progression of CKD. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  16. Variation of milk urea in dairy cattle : a study on factors that affect the relationship between urea concentration in milk and urea excretion in urine

    NARCIS (Netherlands)

    Spek, J.W.

    2013-01-01

    The aim of this thesis was to increase the applicability of milk urea nitrogen concentration (MUN) as a predictor of urinary urea nitrogen excretion (UUN) by identifying and quantifying factors that can explain variation in MUN that is not related to UUN. A literature study was conducted in

  17. Carcass characteristics of sheep fed diets with slow-release urea replacing conventional urea

    Directory of Open Access Journals (Sweden)

    Evanilton Moura Alves

    2014-07-01

    Full Text Available This study aimed to evaluate the effects of adding slow-release urea to replace conventional urea in the diet on carcass characteristics of feedlot sheep. We used 20 Santa Ines x SRD rams, with average body weight of 21.1±1.2 kgand average age of 120 days, distributed in a completely randomized design with 5 treatments. The replacement levels used as treatments were 0, 20, 40, 60, and 80%, composing diets of about 12% crude protein, with 50 % Tifton-85 hay and 50% concentrate. There was no influence of slow release urea on weight at slaughter (35.17 kg, and on hot (16.75 kg and cold (16.24 kg carcass weight, but the yield of these carcasses showed quadratic trend, revealing lower percentages at 48.5 and 47.63% replacement levels, respectively. The weights and yields of cuts did not change, except for the posterior arm, whose values showed a cubic trend. Objective measures of carcass, loin eye area, and subjective evaluations of conformation, finishing and marbling of carcasses were not affected. The subcutaneous fat thickness decreased linearly (4.25 to2.48 mm. The inclusion of slow release urea in the diet changes the yield and reduces subcutaneous fat, however, it does not influence other carcass characteristics.

  18. CACA-TOCSY with alternate 13C-12C labeling: a 13Calpha direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification.

    Science.gov (United States)

    Takeuchi, Koh; Frueh, Dominique P; Sun, Zhen-Yu J; Hiller, Sebastian; Wagner, Gerhard

    2010-05-01

    We present a (13)C direct detection CACA-TOCSY experiment for samples with alternate (13)C-(12)C labeling. It provides inter-residue correlations between (13)C(alpha) resonances of residue i and adjacent C(alpha)s at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C(alpha) nuclei separated by more than one residue. The experiment also provides C(alpha)-to-sidechain correlations, some amino acid type identifications and estimates for psi dihedral angles. The power of the experiment derives from the alternate (13)C-(12)C labeling with [1,3-(13)C] glycerol or [2-(13)C] glycerol, which allows utilizing the small scalar (3)J(CC) couplings that are masked by strong (1)J(CC) couplings in uniformly (13)C labeled samples.

  19. Estimation of glucose carbon recycling in children with glycogen storage disease: A 13C NMR study using [U-13C]glucose

    International Nuclear Information System (INIS)

    Kalderon, B.; Korman, S.H.; Gutman, A.; Lapidot, A.

    1989-01-01

    A stable isotope procedure to estimate hepatic glucose carbon recycling and thereby elucidate the mechanism by which glucose is produced in patients lacking glucose 6-phosphatase is described. A total of 10 studies was performed in children with glycogen storage disease type I (GSD-I) and type III (GSD-III) and control subjects. A primed dose-constant nasogastric infusion of D-[U- 13 C]glucose or an infusion diluted with nonlabeled glucose solution was administered following different periods of fasting. Hepatic glucose carbon recycling was estimated from 13 C NMR spectra. The values obtained for GSD-I patients coincided with the standard [U- 13 C]glucose dilution curve. These results indicate that the plasma glucose of GSD-I subjects comprises only a mixture of 99% 13 C-enriched D-[U- 13 C]glucose and unlabeled glucose but lacks any recycled glucose. Significantly different glucose carbon recycling values were obtained for two GSD-III patients in comparison to GSD-I patients. The results eliminate a mechanism for glucose production in GSD-I children involving gluconeogenesis. However, glucose release by amylo-1,6-glucosidase activity would result in endogenous glucose production of non- 13 C-labeled and nonrecycled glucose carbon, as was found in this study. In GSD-III patients gluconeogenesis is suggested as the major route for endogenous glucose synthesis. The contribution of the triose-phosphate pathway in these patients has been determined

  20. Lactobacillus reuteri 100-23 modulates urea hydrolysis in the murine stomach.

    Science.gov (United States)

    Wilson, Charlotte M; Loach, Diane; Lawley, Blair; Bell, Tracey; Sims, Ian M; O'Toole, Paul W; Zomer, Aldert; Tannock, Gerald W

    2014-10-01

    Comparisons of in vivo (mouse stomach) and in vitro (laboratory culture) transcriptomes of Lactobacillus reuteri strain 100-23 were made by microarray analysis. These comparisons revealed the upregulation of genes associated with acid tolerance, including urease production, in the mouse stomach. Inactivation of the ureC gene reduced the acid tolerance of strain 100-23 in vitro, and the mutant was outcompeted by the wild type in the gut of ex-Lactobacillus-free mice. Urine analysis showed that stable isotope-labeled urea, administered by gavage, was metabolized to a greater extent in Lactobacillus-free mice than animals colonized by strain 100-23. This surprising observation was associated with higher levels of urease activity and fecal-type bacteria in the stomach digesta of Lactobacillus-free mice. Despite the modulation of urea hydrolysis in the stomach, recycling of urea nitrogen in the murine host was not affected since the essential amino acid isoleucine, labeled with a stable isotope, was detected in the livers of both Lactobacillus-free and 100-23-colonized animals. Therefore, our experiments reveal a new and unexpected impact of Lactobacillus colonization on urea hydrolysis in the murine gut. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Radiation inactivation studies of renal brush border water and urea transport

    International Nuclear Information System (INIS)

    Verkman, A.S.; Dix, J.A.; Seifter, J.L.; Skorecki, K.L.; Jung, C.Y.; Ausiello, D.A.

    1985-01-01

    Radiation inactivation was used to determine the nature and molecular weight of water and urea transport pathways in brush border membrane vesicles (BBMV) isolated from rabbit renal cortex. BBMV were frozen to -50 degrees C, irradiated with 1.5 MeV electrons, thawed, and assayed for transport or enzyme activity. The freezing process had no effect on enzyme or transport kinetics. BBMV alkaline phosphatase activity gave linear ln(activity) vs. radiation dose plots with a target size of 68 +/- 3 kDa, similar to previously reported values. Water and solute transport were measured using the stopped-flow light-scattering technique. The rates of acetamide and osmotic water transport did not depend on radiation dose (0-7 Mrad), suggesting that transport of these substances does not require a protein carrier. In contrast, urea and thiourea transport gave linear ln(activity) vs. dose curves with a target size of 125-150 kDa; 400 mM urea inhibited thiourea flux by -50% at 0 and 4.7 Mrad, showing that radiation does not affect inhibitor binding to surviving transporters. These studies suggest that BBMV urea transport requires a membrane protein, whereas osmotic water transport does not

  2. Synthesis and characterization of new thiourea and urea derivatives ...

    Indian Academy of Sciences (India)

    Hasti Sudhamani et al. N. S/O. O. N. F. O. N. S. O. N ... All the required chemicals were purchased from Sigma. Aldrich and the ... of remaining compounds (8b-g) and urea derivatives. (9a-d). ..... Nicholas J H, John G J, Kendra L B, Paul G C, Harold. B H, Lisa L K ... Nadaradjane A Nicod L Guyon C Xicluna A Robert. J F and ...

  3. Novel route for layered double hydroxides preparation by enzymatic decomposition of urea

    Science.gov (United States)

    Vial, S.; Prevot, V.; Forano, C.

    2006-05-01

    This study presents a new route for the preparation of a series of layered double hydroxide materials with controlled textural properties. It concerns the biogenesis of hydrotalcite like phases by Jack bean urease through the enzymatic decomposition process of urea. Different conditions of LDH biogenesis are investigated (urease activity, urea concentration). A comparative study with the precipitation method based on the thermal decomposition of urea (90 °C) is conducted in order to asses the effect of the various urea hydrolysis conditions (kinetic, temperature) and the presence of enzyme in the reaction medium on the structural and textural properties of the as prepared LDH materials. Mechanisms of formation of the LDH phases for both synthesis processes are discussed on basis of their pH control. The PXRD and SEM analysis of samples prepared by the thermal process evidence higher crystallinity and greater particle sizes than LDH obtained in mild biogenic conditions. In the latter case, presence of urease or effect of some M(II) metals may inhibit the crystallization.

  4. Study of the interactions of 13.8 GeV/c protons with the heavy nuclei of the emulsions exposed in magnetic fuel of 170 kgauss; Estudio de las interacciones de protones de 13,8 geV/c con los nucleos pesados de emusiones

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Aleixandre, J L

    1967-07-01

    145 stars with N{sub h}>8 produced by the interactions of 13.8 GeV/c protons with Ag and Br nuclei have been analysed. The emulsion stack was irradiated in a 170 K gauss magnetic field. Statistical results concerning the main characteristics of the different particles emitted are given and the energy balance is evaluated. The main features of both 24 GeV/c protons and 17 GeV/c {pi}- interactions are compared with those we have found for 13.8 GeV/c protons interactions. (Author) 27 refs.

  5. Interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol

    Directory of Open Access Journals (Sweden)

    Marieta Marín Bruzos

    2013-01-01

    Full Text Available En el estudio se evaluaron, mediante análisis de los parámetros fenológicos de las plantas, la interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol. Se emplearon cuatro tratamientos: plantas sin inocular (control, inoculadas con T. paurometabola C-924, inoculadas con R. leguminosarum biovar phaseoli CFH e inoculadas con ambas cepas. Se observaron diferencias significativas (P < 0.01 en los porcentajes de germinación de las plantas tratadas con microorganismos de forma independiente o conjunta con respecto al control sin inocular. Se determinó que la inoculación de T. paurometabola C-924 afectó el proceso de nodulación de R. leguminosarum biovar phaseoli CFH. Sin embargo, esto no incidió de manera significativa en la altura de las plantas ni en el diámetro del tallo, ya que no se encontraron diferencias entre los tratamientos para estos parámetros. Para el número de hojas, los mejores resultados se obtuvieron con la aplicación de T. paurometabola C-924. Se concluyó que la interacción de T. paurometabola C-924 con R. leguminosarum biovar phaseoli CFH en el frijol estimuló significativamente la germinación de las semillas y el número de hojas de las plantas con respecto al control sin inocular. Aunque la aplicación de T. paurometabola C-924 no favoreció la nodulación de R. leguminosarum biovar phaseoli CFH, esto no afectó las características fenológicas del cultivo.

  6. Evaluación de desempeño del micropet focus 120 con los radionúclidos 11C,13N y 18F

    OpenAIRE

    Trejo Ballado, F.; Ortega López, N.; Ojeda Flores, R.; Ávila Rodríguez, M.A

    2010-01-01

    El objetivo de este trabajo es evaluar las características que intervienen en la adquisición de datos y la reconstrucción de imagen de un sistema de micro-tomografía por emisión de positrones (microPET) Focus 120. Características como la resolución en energía, resolución espacial, sensibilidad, tasas de conteo y reconstrucción y calidad de imagen, fueron evaluadas utilizando diferentes maniquíes con tres de los radionúclidos convencionales emisores de positrones comúnmente usados en PET (11C,...

  7. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C2]aminopyrine and L-[1-13C]phenylalanine breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Wigger, Marianne

    2009-09-01

    The aim of this study was to investigate the hepatic microsomal and cytosolic functions by using the 13CO2 breath test in healthy subjects either before or after consumption of red wine. Twelve adults received [13C2]aminopyrine and L-[1-13C]phenylalanine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol per kg per day together with dinner over a 7.5-day period on average. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2 enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery after administration of [13C2]aminopyrine and L-[1-13C]phenylalanine either without or with red wine consumption amounted to 17.0+/-4.4 vs. 14.7+/-3.1% (p=0.170) and 14.0+/-2.8 vs. 11.5+/-3.9% (p=0.084), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the cytosolic function of the human liver in healthy subjects.

  8. Delta /sup 13/C fractionation in Tarbela dam fish

    International Nuclear Information System (INIS)

    Latif, Z.; Sajjad, M.I.; Bilal, R.; Tasneem, M.A.; Khan, I.H.; Ali, M.

    1998-01-01

    The paper focuses on the study of naturally occurring /sup 13/C fractionation in Tarbela dam fish. Craig noted that gamma /sup 13/C values for animal tissues fall in the range as their food supply. DeNiro and Epstein demonstrated clearly that the carbon isotope composition of an animal greatly depends on its diet. The above mentioned statements were observed while studying the isotopic composition of carbon in different parts of the fish. Living fish was purchased from the Haripur side of the Tarbela lake. Different portions were separated and fish diet was collected from the fish stomach. Samples were dried in the oven at 40-50 deg. C for five days. Ground, homogenized and ignited with research grade oxygen at 900-1000 deg. C. CO and CO /sub 2/ were produced and CO was converted to CO/sub 2/ by circulation over CuO gauge furnace at 900 deg. C. CO/sub 2/ was purified using 70 deg. C slush and analyzed on Varian Mat (GD-150) mass spectrometer for gamma /sup 13/C measurements. The results show that fish flesh sup/13 C value is nearly similar to fish diet gamma /sup 13/C. gamma /sup 13/C values to different parts of the fish departed from that of the diet in the sequence: fish swim bladder (-22.04) >ribs (2-22.26)>skin (122.91)>diet (123.22)>flesh (-23.40)> vertebral column (-24.07). It is concluded that diet is easily metabolized in the fish flesh and skin tissues through blood streams without causing any pronounced fractionation. Fractionation was observed in the fish endo skeleton system due to which fish ribs become enriched in gamma /sup 13/C than vertebral column. Fractionation was also detected in visceral muscles (swim bladder) of the fish as comparison with somatic axial trunk muscle (fish flesh). (author)

  9. Effect of urea on protein-ligand association.

    Science.gov (United States)

    Stepanian, Lora; Son, Ikbae; Chalikian, Tigran V

    2017-12-01

    We combine experimental and theoretical approaches to investigate the influence of a cosolvent on a ligand-protein association event. We apply fluorescence measurements to determining the affinity of the inhibitor tri-N-acetylglucosamine [(GlcNAc) 3 ] for lysozyme at urea concentrations ranging from 0 to 8M. Notwithstanding that, at room temperature and neutral pH, lysozyme retains its native conformation up to the solubility limit of urea, the affinity of (GlcNAc) 3 for the protein steadily decreases as the concentration of urea increases. We analyze the urea dependence of the binding free energy within the framework of a simplified statistical thermodynamics-based model that accounts for the excluded volume effect and direct solute-solvent interactions. The analysis reveals that the detrimental action of urea on the inhibitor-lysozyme binding originates from competition between the free energy contributions of the excluded volume effect and direct solute-solvent interactions. The free energy contribution of direct urea-solute interactions narrowly overcomes the excluded volume contribution thereby resulting in urea weakening the protein-ligand association. More broadly, the successful application of the simple model employed in this work points to the possibility of its use in quantifying the stabilizing/destabilizing action of individual cosolvents on biochemical folding and binding reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Dissolution of lignin in green urea aqueous solution

    Science.gov (United States)

    Wang, Jingyu; Li, Ying; Qiu, Xueqing; Liu, Di; Yang, Dongjie; Liu, Weifeng; Qian, Yong

    2017-12-01

    The dissolution problem is the main obstacle for the value-added modification and depolymerization of industrial lignin. Here, a green urea aqueous solution for complete dissolution of various lignin is presented and the dissolution mechanism is analyzed by AFM, DLS and NMR. The results show that the molecular interaction of lignin decreases from 32.3 mN/m in pure water to 11.3 mN/m in urea aqueous solution. The immobility of 1H NMR spectra and the shift of 17O NMR spectra of urea in different lignin/urea solutions indicate that the oxygen of carbonyl in urea and the hydrogen of hydroxyl in lignin form new hydrogen bonds and break the original hydrogen bonds among lignin molecules. The shift of 1H NMR spectra of lignin and the decrease of interactions in model compound polystyrene indicate that urea also breaks the π-π interactions between aromatic rings of lignin. Lignin dissolved in urea aqueous has good antioxidant activity and it can scavenge at least 63% free radicals in 16 min.

  11. Indications, diagnostic tests and Helicobacter pylori eradication therapy: Recommendations by the 2nd Spanish Consensus Conference Indicaciones, métodos diagnósticos y tratamiento erradicador de Helicobacter pylori: Recomendaciones de la II Conferencia Española de Consenso

    Directory of Open Access Journals (Sweden)

    J. Monés

    2005-05-01

    eradicating therapies is indicated, and finally the test and treat strategy is considered adequate, however only under certain circumstances.Se resumen los resultados de la II Conferencia Española de Consenso para la práctica más idonea en cuanto a las indicaciones de erradicación, métodos diagnósticos y pautas de tratamiento de la infección por Helicobacter pylori. La conferencia se basó en la búsqueda bibliográfica con la base de datos de "Medline", los resumenes de tres congresos internacionales y de los congresos nacionales. Los resultados fueron consensuados y aprobados por todo el grupo. Los resultados se complementan indicando los grados de evidencia y el nivel de recomendación, de acuerdo con la clasificación utilizada en las Guías de Práctica Clínica editadas con la Colaboración Cochrane. Se analizan las indicaciones convincentes de la erradicación del H. pylori (úlcera péptica, erosiones duodenales sin antecedentes de AAS o AINE, linfoma MALT y las indicaciones menos convincentes (dispepsia funcional, pacientes en tratamiento con AAS a dosis bajas como antiagregante plaquetario, muñón de gastrectomía en operados de cáncer gástrico, familiares de primer grado de pacientes con cáncer gástrico, gastritis linfocítica y enfermedad de Menètriér. Se exponen recomendaciones diagnósticas de la infección ante diversas situaciones clínicas (úlcera péptica, hemorragia digestiva secundaria a úlcera, control de erradicación, pacientes en tratamiento antibiótico o antisecretor actual o reciente, así como los métodos diagnósticos que requieren toma de biopsia (histología, test rápido de la ureasa y cultivo cuando se necesita endoscopia para el diagnóstico clínico y los métodos no invasivos que no requieren biopsia (test de aliento con 13C-urea, tests serológicos y test de antígenos en heces cuando la endoscopia es innecesaria. En cuanto al tratamiento se priorizan aquellos de primera elección (triple terapia con un IBP y dos antibi

  12. Determination of urea utilization of rice at different growth stages by 15N tracer technique

    International Nuclear Information System (INIS)

    Korkmaz, A.; Halitligil, M.B.; Torun, M.

    1991-01-01

    This study reported here examines the percent utilization of 15 N labelled urea by rice when it is broadcasted over the soil surface or mixed within 10 cm soil at different vegetative stages. The experimental plots were arranged in randomized block design and replicated 3 times. N was applied at a rate of 120 kg N/ha as single or split applications at four different times during the growing season. Labelled urea was applied to 0.5x0.5 m plots only in 1988, however in 1989 unlabelled urea was applied to all plots. Stover and seed samples from each plot were harvested, dried at 65 0 C, weighed and kilogram per hectare were calculated in 1988. Also, the yield surplus per kilogram N was calculated for each treatment and this was indicated as urea fertilizer efficiency coefficient. Total N and 15 N analysis for stover and seed were done. Significant differences (at 0.05 level) were observed in stover and seed yields, when 120 kg/ha urea was split applied at different growth stages. Similar yield responses were obtained in 1988 and 1989. Highest seed yields were obtained when half of urea was applied at planting and the other half was applied at one week before heading. The results also showed that the highest utilization of urea for seed plus stover was obtained from the second half of urea (60 kg N/ha) applied one week before heading. Percent utilization of urea by rice also differed according to the rate applied at each stage

  13. Cuidados paliativos a los pacientes con cáncer en el hospicio de Seychelles

    Directory of Open Access Journals (Sweden)

    Armando Carlos Roca Socarrás

    2013-03-01

    Full Text Available Fundamento: la alta prevalencia del cáncer en los países de medios y bajos ingresos incrementa a diario las necesidades de cuidados en el hospicio. Objetivo: determinar el comportamiento de algunas variables biológicas en pacientes con cáncer en estadio terminal. Métodos: estudio descriptivo de 28 pacientes con diagnóstico de neoplasia en estadio terminal, ingresados en el hospicio de Seychelles entre febrero de 2010 y febrero de 2011. Se analizó el comportamiento del cáncer en relación con las variables: edad, sexo, localización primaria, respuesta al índice de Charlson, escalas de Karnofsky y ECOG, presencia de enfermedades crónicas no transmisibles y escenario de salud responsable de la remisión. Resultados: el 54,9 % de los pacientes ingresados en el hospicio presentaban una enfermedad oncológica, de ellos el 53,57 % del sexo masculino. El grupo de edad con mayor número de casos fue el de 50 a 59 años, con una edad media de 68,6 años (±15,71. La neoplasia de cabeza y cuello en los hombres y colorectal en las mujeres fueron los diagnósticos más frecuentes. En general la estadía media estuvo en 40,5 días (±60,23. La hipertensión arterial y la diabetes mellitus fueron las enfermedades crónicas no transmisibles más frecuentes. El 75 % de los casos fue remitido desde el escenario hospitalario. Conclusiones: el cáncer en estadio terminal muestra un comportamiento que permite anticipar una adecuada estrategia de transición hacia los cuidados paliativos que brinda el hospicio.

  14. Apoyo social percibido y recibido en mujeres diagnosticadas con cáncer de seno

    OpenAIRE

    Rengifo Hincapié, Marcela

    2017-01-01

    Debido a que el cáncer de seno, constituye en la actualidad una enfermedad crónica y en ese sentido, existe cada vez un mayor número de casos de mujeres viviendo con esta patología, surge la necesidad inherente de crear estrategias que contribuyan en brindar una mejor calidad de vida a esta población. Es así como la presente investigación tuvo como objetivo general comprender las valoraciones que realizan mujeres diagnosticadas con cáncer de seno frente al apoyo social percibido y recibido. L...

  15. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of 111In-DTPA-D-Phe1-octreotide, 99mTc-MIBI, 14C-triolein and 14C-urea, and development of dosimetric models

    International Nuclear Information System (INIS)

    Leide Svegborn, S.

    1999-03-01

    Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with 111 In-DTPA-D-Phe 1 -octreotide (for diagnosis of neuroendocrine tumours) and 99m Tc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. 111 In-DTPA-D-Phe 1 -octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). 99m Tc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of 14 CO 2 , in exhaled air from patients undergoing 14 C-breath tests, with special application to 14 C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of 14 C, and was used together with liquid scintillation counting in an investigation of the biokinetics of 14 C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for 14 C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children, resulting in an effective dose of approximately 0.002 mSv per

  16. 76 FR 78885 - Solid Urea From the Russian Federation and Ukraine: Continuation of Antidumping Duty Orders

    Science.gov (United States)

    2011-12-20

    ... foreseeable time. See Solid Urea From Russia and Ukraine, 76 FR 77015 (December 9, 2011), and ITC Publication... revocation of the antidumping duty orders on solid urea from the Russian Federation (Russia) and Ukraine... Russia and Ukraine,\\1\\ pursuant to section 751(c) of the Tariff Act of 1930, as amended (the Act). See...

  17. N-Urea Efficiency In Lowland Rice Applied With Azolla

    International Nuclear Information System (INIS)

    Rasjid, Havid; Sisworo, E.L.; Wemay, Y.; Sisworo, W.H.

    2000-01-01

    Two N-fertilizer experiments have been conducted using urea tablet and prill urea combined with Azolla application. Twelve treatments have been tested using 2 rice varieties namely Atomita-4 and IR-64. To enable the determination of N-urea efficiency 15 N labelled urea was used. The experiments were conducted in the dry and wet season (DS and WS) 1994/1995 at the experimental station, pusaka negara, Subang West Java. Data obtained from the two experiments showed that the highest N-urea efficiency was found in Atomita-4 applied with urea-tablet (DS=46,1%, WS= 35,8%). Letting the Azolla grow during one lowland rice growth period could increase the N-urea prill efficiency (±5%) compared when no azolla was applied. Apparently Atomita-4 could use N-urea more efficiently compared to IR-64, showing higher grain yield (atomita-4 DS=6.2 ton ha -1 WS=5.9 ton ha -1 ) vs IR-64 (DS=5.8 ton ha -1 , WS=5.3 ton ha -1 ). Decreasing the levels of TSP not influence to the urea efficiency at the DS and WS

  18. Urea utilization in protein deficient rats

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, N [Hyogo College of Medicine, Nishinomiya, Hyogo (Japan)

    1982-06-01

    Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The /sup 15/N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of /sup 15/N-urea (10 mg/100gB.W.) and higher level of /sup 15/N concentration in plasma protein in LPD group was maintained thereafter. The /sup 15/N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The /sup 15/N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of /sup 15/N-urea (10mg/100gB.W.). However, the /sup 15/N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis.

  19. Urea utilization in protein deficient rats

    International Nuclear Information System (INIS)

    Tanaka, Noriko

    1982-01-01

    Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The 15 N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of 15 N-urea (10 mg/100gB.W.) and higher level of 15 N concentration in plasma protein in LPD group was maintained thereafter. The 15 N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The 15 N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of 15 N-urea (10mg/100gB.W.). However, the 15 N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis. (J.P.N.)

  20. Lipase-catalyzed synthesis of fatty acid amide (erucamide) using fatty acid and urea.

    Science.gov (United States)

    Awasthi, Neeraj Praphulla; Singh, R P

    2007-01-01

    Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %.

  1. Poblaciones linfocitarias, células dendríticas y perfil de citoquinas en ratones con melanoma tratados con Uncaria tomentosa

    Directory of Open Access Journals (Sweden)

    Iván Lozada-Requena

    Full Text Available Objetivos. Evaluar el efecto inmunomodulador sobre poblaciones linfocitarias, células dendríticas (DC, citoquinas Th1/Th2/Th17 (T-helper e inflamatorias en el ámbito sistémico y/o en el microambiente tumoral de ratones con o sin melanoma. Materiales y métodos. Se obtuvieron muestras de sangre periférica y/o de tumores primarios de ratones con melanoma B16 tratados o no con un extracto hidroalcohólico de Uncaria tomentosa (UT con 5,03% de alcaloides oxindólicos pentacíclicos (UT-POA obtenido de la corteza de la planta. Todos los ensayos de medición de células y citoquinas fueron realizados por citometría de flujo. Resultados. UT-POA a nivel sistémico incrementa la relación CD4/CD8a (Cluster of Differenciation, mientras que la activación celular es inversamente proporcional; incrementa la proporción de DCm (DC mieloides; induce un perfil Th1 proinflamatorio y reduce la respuesta Th17. TNF-a (tumor necrosis factor alpha y IL-17A (interleuquina correlacionan positiva y negativamente con la relación CD4/CD8a. Conclusiones. El incremento de Th1 (TNF-a puede tener como consecuencia el incremento de linfocitos CD4 o la activación de macrófagos M1. Aunque UT-POA muestra un incremento de DCm, este no es dosis-dependiente. La disminución de Th17 (IL-17A puede favorecer el funcionamiento de los linfocitos CD8a. UT-POA muestra mejores efectos inmunomoduladores en el ámbito sistémico que intratumoral

  2. PEDOGENIC CARBONATE δ13C AND ENVIRONMENTAL PRECIPITATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Marcella Catoni

    2011-12-01

    Full Text Available Carbon isotopic analysis is a useful tool for investigating paleoenvironments, as the pedogenic carbonate δ13C is related to δ13CSOM and to the proportions of C3/C4 plants. In this work we interpreted the paleoenvironmental conditions at the time of carbonate precipitation in soils formed under different climates and during different geological ages. Samples were taken from a Bk (PR1, Holocene and from two Bkm horizons (PR2 and PR3, Pleistocene. When the mean δ13C plant values and the most plausible paleotemperatures were used in the evaluation, PR1 showed a lower percentage of C4 plants (48% than Pleistocene soils (~53%, in agreement with paleoclimate changes. When instead the δ13C values of current plants were used for PR1, C4 plants ranged from 59 (12°C to 66% (18°C, suggesting two possible interpretations: either plant species changed during the Holocene, or the plant mean values normally used in the literature are not suitable for Pleistocene reconstructions

  3. Late pleistocene-recent atmospheric δ13C record in C4 grasses

    International Nuclear Information System (INIS)

    Toolin, L.J.; Eastoe, C.

    1993-01-01

    Samples of Setaria species from packrat middens, herbarium specimens and modern plants preserve a record of δ 13 C of atmospheric CO 2 from 12,600 Bp to the present. No secular trend is detected between 12,600 and 1,800 Bp, when the mean value of δ 13 C during that period was -6.5 ± 0.1 per-thousand (the error is the standard deviation of the mean). The value agrees with δ 13 C averages of pre-industrial CO 2 from polar ice cores, and differs significantly from modern regional (-8.2 ± 0.1 per-thousand) and global (-7.7 per-thousand) values, which are higher because of fossil fuel burning

  4. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  5. Detection of interstellar (C-13)N toward Zeta Ophiuchi

    International Nuclear Information System (INIS)

    Crane, P.; Hegyi, D.J.

    1988-01-01

    Observations of a diffuse interstellar cloud toward Zeta Oph, obtained with resolution 100,000-150,000 near the 3874.608-A R(0) line of (C-12)N using a coude echelle spectrograph on the 1.4-m telescope at ESO during 1984 and 1985, are reported. Data from 54 20-min runs were fitted to Gaussian line shapes using the line center, depth, and width of the R(0) and R(1) lines of (C-12)N and the line center and depth of the R(0) line of (C-13)N as fitting parameters. The (C-13)N R(0) line, with equivalent width 0.190 + or - 0.020 mA, was detected 173.7 + or - 0.8 mA to the red of (C-12)N R(0); the corresponding isotope abundance ratio, (C-12)N/(C-13)N = 47.3 + 5.5 or -4.4, is shown to be in good agreement with previous measurements for CH(+) (Hawkins et al., 1985). 13 references

  6. 2-Ureido-1,3-thiazol-3-ium dihydrogen phosphate

    Directory of Open Access Journals (Sweden)

    Kateryna Gubina

    2011-07-01

    Full Text Available The title compound, C4H6N3OS+·H2PO4−, (I, was obtained as a result of hydrolysis of [(1,3-thiazol-2-ylaminocarbonyl]phosphoramidic acid, (II, in water. X-ray analysis has shown that the N—P bond in (II breaks, leading to the formation of the substituted carbamide (I. This compound exists as an internal salt. The unit cell consists of a urea cation and an anion of H2PO4−. Protonation of the N atom of the heterocyclic ring was confirmed by the location of the H atom in a difference Fourier map. The molecules of substituted urea are connected by O...O hydrogen bonds into unlimited planes. In turn, those planes are connected to each other via N—H...O hydrogen bonds with molecules of phosphoric acid, forming a three-dimensional polymer.

  7. The synthesis of Org 3770 labelled with 3H, 13C and 14C

    International Nuclear Information System (INIS)

    Kaspersen, F.M.; Rooij, F.A.M. van; Sperling, E.G.M.; Wieringa, J.H.

    1989-01-01

    The syntheses of 1,2,3,4,10,14b-hexahydro-2-methylpyrazino[2,1-a]pyrido[2,3-c][2]benazepine (Org 3770) labelled with 3 H (and 2 H), 13 C and 14 C are described. Tritiated Org 3770 was prepared either by exchange under alkaline conditions with tritiated water or catalytic reductive dehalogenation of a chloro analogue with 3 H 2 . 13 C-labelled material was obtained in a seven-step synthesis starting from 13 C-labelled benzene whereas 14 C-Org 3770 was prepared in a three-step synthesis starting with 14 CO 2 . All labelled compounds were analyzed by TLC, HPLC, MS and NMR. (author)

  8. Urea kinetics during sustained low-efficiency dialysis in critically ill patients requiring renal replacement therapy.

    Science.gov (United States)

    Marshall, Mark R; Golper, Thomas A; Shaver, Mary J; Alam, Muhammad G; Chatoth, Dinesh K

    2002-03-01

    reference methods were 0.61 and 24.8 mL/min, respectively, and not significantly different when determined by blood-based methods. A single-pool urea kinetic model adequately described intradialytic PUN profiles, indicating that SLED was associated with minimal urea disequilibrium. This was supported by the parity between hemodialyzer and whole-body urea clearances, and the mean postdialytic urea rebound of 4.1% (P = 0.13 versus zero). Additional prospective studies are needed in this setting to define the optimal method for dialysis quantification, targets for azotemic control, and optimal modality of renal replacement therapy. In conclusion, SLED delivers a high dose of dialysis with minimal associated urea disequilibrium and can be quantified by Kt/V, SRI, and EKR from blood-based methods using single-pool urea kinetic models. Copyright 2002 by the National Kidney Foundation, Inc.

  9. Site-selective {sup 13}C labeling of proteins using erythrose

    Energy Technology Data Exchange (ETDEWEB)

    Weininger, Ulrich, E-mail: ulrich.weininger@physik.uni-halle.de [Lund University, Department of Biophysical Chemistry, Center for Molecular Protein Science (Sweden)

    2017-03-15

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with {sup 13}C and/or {sup 1}H, which is achieved in the most general way by using site-selectively {sup 13}C-enriched glucose (1- and 2-{sup 13}C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively {sup 13}C-enriched erythrose (1-, 2-, 3- and 4-{sup 13}C) as a suitable precursor for {sup 13}C labeled aromatic side chains. We quantify {sup 13}C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the {sup 13}C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated {sup 13}C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective {sup 13}C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  10. The effects of a hind-gut fermentation on urea kinetics in sheep

    International Nuclear Information System (INIS)

    Oncuer, A.

    1988-01-01

    Four female sheep were fitted with rumen cannulas and abomasal and ileal infusion catheters; one of the sheep was also fitted with a cannula at the caecum. All animals were nourished wholly by intragastric infusion of nutrients to the rumen and abomasum and received in addition three levels of nutrient infusion into the terminal ileum in order to achieve different levels of hind-gut fermentation. The ileal infusion treatments were (1) water infusion; (2) 25 g/d starch and 50 g/d cellulose infusion; (3) 50 g/d starch and 50 g/d cellulose infusion. In each 2 week period, the first 7 days served as the preliminary period infusion. Days 8-12 inclusive were used for quantitative collection of faeces and urine for digestibility and nitrogen balance measurement and on day 14 an injection of ( 14 C)-urea was given into a jugular vein for measurement of urea kinetics. Hind-gut fermentation did not significantly affect any parameters of urea metabolism. Although degradation of urea did not differ significantly between treatments an increase of over 2 g/d was observed in progressing from the lowest to the highest level of hind-gut infusion. Faecal nitrogen excretion increased significantly from 21.8 to 74.7 mg N/kg 0.75 /d (P 0.01) and urinary urea-N decreased significantly from 278.9 to 252.3 mg/kg 0.75 /d (P 0.05) in the presence of a hind-gut fermentation. Close relationships were observed between various parameters of urea metabolism

  11. Computational and Pharmacological Evaluation of Ferrocene-Based Acyl Ureas and Homoleptic Cadmium Carboxylate Derivatives for Anti-diabetic Potential

    Directory of Open Access Journals (Sweden)

    Shahar Bano

    2018-01-01

    Full Text Available We investigated possible anti-diabetic effect of ferrocene-based acyl ureas: 4-ferrocenyl aniline (PFA, 1-(4-chlorobenzoyl-3-(4-ferrocenylphenyl urea (DPC1, 1-(3-chlorobenzoyl-3-(4-ferrocenylphenyl urea (DMC1, 1-(2-chlorobenzoyl-3-(4-ferrocenylphenyl urea (DOC1 and homoleptic cadmium carboxylates: bis (diphenylacetato cadmium (II (DPAA, bis (4-chlorophenylacetato cadmium (II (CPAA, using in silico and in vivo techniques. PFA, DPC1, DMC1, DOC1, DPAA and CPAA exhibited high binding affinities (ACE ≥ −350 Kcal/mol against targets: aldose reductase, peroxisome proliferator-activated receptor γ, 11β-hydroxysteroid dehydrogenase-1, C-alpha glucosidase and glucokinase, while showed moderate affinities (ACE ≥ −250 Kcal/mol against N-alpha glucosidase, dipeptidyl peptidase-IV, phosphorylated-Akt, glycogen synthase kinase-3β, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase, whereas revealed lower affinities (ACE < −250 Kcal/mol vs. alpha amylase, protein tyrosine phosphatases 1B, glycogen phosphorylase and phosphatidylinositol 3 kinase. In alloxan (300 mg/Kg-induced diabetic mice, DPAA and DPC1 (1–10 mg/Kg at day 1, 5, 10, 15, and 20th decreased blood glucose levels, compared to diabetic control group and improved the treated animals body weight. DPAA (10 mg/Kg and DPC1 (5 mg/Kg in time-dependent manner (30–120 min. enhanced tolerance of oral glucose overload in mice. DPAA and DPCI dose-dependently at 1, 5, and 10 mg/Kg decreased glycosylated hemoglobin levels in diabetic animals, as caused by metformin. These results indicate that aforementioned derivatives of ferrocene and cadmium possess anti-diabetic potential.

  12. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  13. Pengaruh Suplementasi Baking Soda dalam Pakan terhadap Urea Darah dan Urea Susu Sapi Perah Laktasi

    Directory of Open Access Journals (Sweden)

    W. A. Harjanti

    2017-06-01

    Full Text Available The aim of the research was to assess the effect of suplementation of sodium bicarbonate in feed rations on the concentration of Blood Urea Nitrogen (BUN and Milk Urea Nitrogen (MUN of lactating dairy cattle. The materials used were 12 lactating Friesian Holstein cattle in the 1th lactation period and the month lactation of 5 and 6th. The experiment used a completely randomized design with 3 treatments and 4 replications. The experimental treatmens were basal ration (T0, and basal ration supplemented with 0,8 % (T0 and 1 % (T2 of sodium bicarbonate, on a dry matter (DM basis. The parameters determined were crude protein intake (CPI and the concentration of BUN and MUN. The data were analyzed using variance the F-test. The result showed that the CPI, and the concentration of BUN and MUN were not affected by the treatments. The CPI were 2.097,43 ; 2.079,19 and 2.053,17 g/d. The concentration of BUN were 14,04 ; 13,05 and 12,75 mg/dl, whereas the concentration of MUN were 12,43 ; 10,01 and 10,07 mg/dl for T0, T1 dan T2 respectively. Overall, 0,8 and 1% of sodium bicarbonate supplementations into feed ration was not found to significantly alter the quantity of crude protein intake and the concentration of BUN and MUN in lactating dairy cattle in the present study.

  14. Radiation-induced in-source polymerization of acrylonitrile in urea canal complex

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Abe, Toshihiko; Kobayashi, Yasushi.

    1975-01-01

    Effect of reaction conditions on the radiation-induced in-source polymerization of acrylonitrile in urea canal complex and the properties of obtained polyacrylonitriles were investigated. The results were discussed in comparison with previously reported of the post-polymerization experiments. 1) Rate of polymerization and viscosity (eta sub(sp)/C) were the highest when the molar ratio of acrylonitrile to urea in canal complex was unity. Similar results were also obtained in the post-polymerization. However, eta sub(sp)/C exhibited different behavior on polymerization time in comparison with post-polymerization. 2) The initial rate (Rsub(p)) of polymerization is proportional to the dose rate (I) at low dose rate, but at high dose rates (above 2x10 5 r/hr) makes Rsub(p) proportional to Isup(0.5). 3) Molecular weight distribution become broader with increasing polymerization time and is broad as compared with those obtained by the post-polymerization. G-value of initiation of polymerization decreased with increasing polymerization time. These value was larger than the that obtained in the post-polymerization. 4) The stereoregularity of the polyacrylonitriles was independent of the molar ratio of acrylonitrile to urea in the canal complex and conversion. 5) The appearance of the polyacrylonitriles observed by the scanning electron microscope changed from curled string to extended one as the polymerization proceed. 6) Infrared spectrum revealed the ketenimine and cyclization structure in the polyacrylonitriles obtained below -100 0 C. The content of these abnormal structures increased with increasing conversion. (auth.)

  15. Assessing the use of delta C-13 natural abundance in separation of root and microbial respiration in a Danish beech (¤Fagus Sylvatica¤ L.) forest

    DEFF Research Database (Denmark)

    Formanek, P.; Ambus, P.

    2004-01-01

    on the root respiration contribution to total CO2 effluxes. The delta(13)C isotopic analyses Of CO2 were performed using a FinniganMAT Delta(PLUS) isotope-ratio mass spectrometer coupled in continuous flow mode to a trace gas preparation-concentration unit (PreCon). Gas samples in 2-mL crimp seal vials were...... samples are not representative for the C-pools actively undergoing decomposition. Copyright (C) 2004 John Wiley Sons, Ltd....

  16. Synthesis of 15N-labelled urea and methylenediurea

    International Nuclear Information System (INIS)

    Murray, T.P.; Jones, G.T.

    1985-01-01

    A new technique was developed for the large-scale synthesis of 15 N-labelled urea at low enrichment levels. The synthesis is based on nucleophilic displacement of the phenoxide ion from phenyl carbonate and uses anhydrous ammonia as the nucleophile. In previous reports a copper catalyst was used; however, in this study it was found that the copper resulted in product decomposition and tar formation, which makes product purification difficult. A novel set of reaction conditions was developed: no catalyst was used, and no product decomposition or tar formation occurred. The reaction product was easily purified, and consistently high yields of 15 N-labelled urea were obtained. 15 N-labelled methylenediurea was prepared by the dilute solution reaction of formalin with 15 N-labelled urea. The methodology developed for the reclamation of unreacted urea resulted in minimum loss of labelled urea. High performance liquid chromatography has been used to determine the chemical purity of both urea and methylenediurea. (author)

  17. Ab initio/GIAO-CCSD(T) (13)C NMR study of the rearrangement and dynamic aspects of rapidly equilibrating tertiary carbocations, C6H13(+) and C7H15(+).

    Science.gov (United States)

    Olah, George A; Prakash, G K Surya; Rasul, Golam

    2016-01-05

    The rearrangement pathways of the equilibrating tertiary carbocations, 2,3-dimethyl-2-butyl cation (C6H13(+), 1), 2,3,3-trimethyl-2-butyl cation (C7H15(+), 5) and 2,3-dimethyl-2-pentyl cation (C7H15(+), 8 and 9) were investigated using the ab initio/GIAO-CCSD(T) (13)C NMR method. Comparing the calculated and experimental (13)C NMR chemical shifts of a series of carbocations indicates that excellent prediction of δ(13)C could be achieved through scaling. In the case of symmetrical equilibrating cations (1 and 5) the Wagner-Meerwein 1,2-hydride and 1,2-methide shifts, respectively, produce the same structure. This indicates that the overall (13)C NMR chemical shifts are conserved and independent of temperature. However, in the case of unsymmetrical equilibrating cations (8 and 9) the Wagner-Meerwein shift produces different tertiary structures, which have slightly different thermodynamic stabilities and, thus, different spectra. At the MP4(SDTQ)/cc-pVTZ//MP2/cc-pVTZ + ZPE level structure 8 is only 90 calories/mol more stable than structure 9. Based on computed (13)C NMR chemical shift calculations, mole fractions of these isomers were determined by assuming the observed chemical shifts are due to the weighted average of the chemical shifts of the static ions. © 2015 Wiley Periodicals, Inc.

  18. Organic compounds preparation with 14 C

    International Nuclear Information System (INIS)

    Shirvani, Gholam Hossein.

    1996-09-01

    Active urea is a basic reagent for the synthesis of active uric-8- 14 C acid. In our manner, activated Barium carbonate with specified activity was placed in a special furnace with ability of passing gases. Then, ammonia gas was passed through it at about 850 Degree C to obtain Barium Cyanamide. Reaction of the produced compound with CO 2 , and then acidification of the mixture, gave activated urea. Condensation of the urea with Ethylcyanoacetate, produce 6-Aminouracil which upon nitrosation, reduction and then condensation with urea, the desired Uric-8- 14 C acid was synthesized. (author). 148 refs.,

  19. Química de Coordinación de las 3-Benzoiltio (Seleno Ureas

    Directory of Open Access Journals (Sweden)

    Lothar Beyer

    2011-04-01

    Full Text Available Las 3-benzoiitlo (seleno ureas-1,1-dlsustltuldas forman quelatos metálicos. Aquí se describen la síntesis y las propiedades de los ligandos y de algunos derivados, considerando especialmente la estructura en solución. La estructura molecular de los quelatos metálicos fue investigada por rayos X. La energía libre de activación para la rotación Impedida del grupo Et2N alrededor del enlace N-C(X (X = S, Se fue determinada por espectroscopia RMN^H. La barrera rotacional en los quelatos es mayor que la de los ligandos libres. Algunos aspectos del enlace químico y de la distribución electrónica en los quelatos fueron Investigados por espectroscopia fotoelectrónlca de rayos X. Se propone un nuevo método para la determinación de la estabilidad termodinámica de los quelatos azufrados de níquel (11, utilizando los valores M'''^% de la espectroscopia de masas. Mediciones calorimétricas de la formación de los aductos de blspirldlna de los complejos de níquel (11 con los ligandos mencionados y sus CH-análogos muestran diferencias significativas entre los dos tipos. Los resultados ESCA de los aductos NO metálicos confirman ia carga negativa sobre el NO. Las 3-benzolltloúreas-1-monosustltuldas pueden coordinarse con los átomos S/0 ; N/OoSsólo.

  20. Ansiedad, resiliencia e inteligencia emocional percibida en mujeres con cáncer de mama

    OpenAIRE

    García-Maroto Fernández, Sagrario

    2016-01-01

    Introducción. En el presente trabajo de investigación se ha estudiado la ansiedad, la resiliencia y la inteligencia emocional percibida en un grupo de mujeres con cáncer de mama y otro grupo de mujeres sin la enfermedad. Así mismo, se ha realizado el diseño, la aplicación y la evaluación de un programa de inteligencia emocional en un grupo de mujeres con cáncer de mama. - Contenido de la investigación. El marco teórico se centra en los constructos principales de estudio, ansiedad, resilien...

  1. Carbon-13 kinetic isotope effects in the decarbonylations of lactic acid containing 13C at the natural abundance level

    International Nuclear Information System (INIS)

    Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.

    1992-01-01

    The 13 C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 20-80 deg C. The 13 C (1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40 deg C. Below this temperature the 13 C isotope effect in the decarbonylation of lactic acid by concentrated sulfuric acid is normal similarly as has been found in the decarbonylation of lactic [1- 14 C] acid. The experimental values of k (12C) /k (13C) ratios of isotopic rate constants for 12 C and 13 C are close to, but slightly higher than theoretical 13 C-kinetic isotope effects calculated (neglecting tunneling) under the asumption that the C (1) -OH bond is broken in the rate-controlling step of the dehydration reaction. Dilution of concentrated sulfuric acid with water up to 1.4 molar (H 2 O)/(H 2 SO 4 ) ratio caused the increase of the 13 C isotope fractionation from 1.0273 found in concentrated sulfuric acid at 80.5 deg C to 1.0536±0.0008 (at 80.6 deg C). A discussion of the abnormally high temperature dependence of 14 C and 13 C isotope fractionation in this reaction and the discussion of the problem of relative 14 C/ 13 C kinetic isotope effects is given. (author) 18 refs.; 2 tabs

  2. The 12C/13C Isotopic Ratio in Planetary Nebulae as Deduced from IUE Data

    Science.gov (United States)

    Miskey, C. L.; Feibelman, W. A.; Bruhweiler, F. C.

    2000-05-01

    The relative abundances of C, N, and O and the isotopic ratio of 12C/13C represent tracers of nucleosynthesis in intermediate stars with main-sequence masses between 0.6 and 8.0 solar masses in our Galaxy. Determining these abundances and the isotopic 12C/13C ratio in planetary nebulae (PNe) represent perhaps the best means to discern exactly how the ISM is enriched by CNO stellar nucleosynthesis. Walsh et al. (1996) and Clegg et al. (1997), using the Hubble Space Telescope, have derived the isotopic 12C/13C abundance ratio in the galactic carbon-rich PN, NGC 3918, and placed marginal constraints on it for the Magellanic PNe, N2 (SMC) and N122 (LMC). This was done using the well-known 12C 3P-1S (J=1-0 and J=2-0) transitions of C+2 at 1906.68 Angstroms and 1908.77 Angstroms and a J=0-0 transition at 1909.6 Angstroms, which is strictly forbidden in 12C. The finite nuclear spin of 13C (I=1/2) permits a corresponding F=1/2-1/2 electric dipole transition not seen in 12C. Since the 1909.6 Angstroms line is well separated from the other two 12C transitions, it provides an important means of determining 12C/13C in planetary nebulae. We have just completed a search of archival International Ultraviolet Explorer (IUE) high-dispersion spectra of approximately three dozen PNe, and derived 12C/13C ratios of 39 and 23 for the galactic PNe, NGC 2440 and NGC 6302, respectively. These are values much lower than the solar value of 89. In the other objects, the limited S/N of the IUE data indicate 12C/13C ratio upper limits much higher than 50. The implications of these results and their pertinence to stellar evolution are discussed.

  3. Profilaxis primaria para tromboembolismo venoso en pacientes ambulatorios con cáncer sometidos a quimioterapia

    Directory of Open Access Journals (Sweden)

    2013-07-01

    Conclusiones de los autores: La tromboprofilaxis primaria con HBPM redujo significativamente la incidencia del TEV sintomático en los pacientes ambulatorios con cáncer tratados con quimioterapia. Sin embargo, la ausencia de poder estadístico obstaculiza la posibilidad de establecer conclusiones definitivas sobre los efectos en cuanto a los resultados principales de seguridad, lo cual obliga a la realización de estudios adicionales para determinar el cociente riesgos/beneficios de la HBPM en este contexto.

  4. Tratamiento antibiótico oral versus intravenosopara la neutropenia febril en pacientes con cáncer

    Directory of Open Access Journals (Sweden)

    2014-05-01

    Conclusiones de los autores: Según los datos actuales, el tratamiento oral es una opción aceptable al tratamiento con antibióticos intravenosos en los pacientes con cáncer con neutropenia febril (se excluye a los pacientes con leucemia aguda hemodinámicamente estables, sin insuficiencia orgánica y sin neumonía, infección de una vía central o infección grave de partes blandas. El IC amplio en la mortalidad permite el uso actual del tratamiento oral en grupos de pacientes con bajo riesgo de mortalidad esperado y los estudios de investigación adicionales deben tener como objetivo aclarar la definición de pacientes con bajo riesgo.

  5. Ensayo de fertilización del pasto puntero (Hyparrhenia rufa con un diseño de superficies de respuesta en la zona de Chaparral, Tolima

    Directory of Open Access Journals (Sweden)

    Buritica Martínez Hernando

    1991-12-01

    Full Text Available Se realizó un esayo de fertilización con NPK empleando urea, superfosfato tripley cloruro de potasio como fuentes en pasto puntero (Hyparrhenia rufa en la vereda Espíritu Santo, municipio de Chaparral, Tolima en suelos francos arenosos de laderade baja a mediana fertilidad natural, altura de 1.000 m.s.n.m., temperatura diaria de 25 grados, precipitación promedia anual de 2.500 mms. y una estación seca bien definida entre los meses de junio a septiembre, utilizando el modelo de superficies de respuesta desarrollado por Box y Hunter, ex·puesto por Cochran y Cox y recomendado por Instituto Colombiano Agropecuario. Los modelos de regresión obtenidos, muestran incrementos crecientes en la producción de forraje verde y contenido proteínico para las aplicaciones crecientes de nitrógeno y fósforo, con máximos equivalentes a 41 toneladas/Ha y 3.5% con aplicaciones de 400 y 200 kgs/Ha de úrea y superfosfato triple. En las condiciones de ensayo, se demuestra la conveniencia de la aplicaciónde nitrógeno y fósforo en cantidades comprendidas entre 150 a 200 y 75 a too kilos de úrea y superfosfato triple por hectárea respectivamente.
    A field experiment were conducted in order to know the response of "Puntero" grass (Hyparrhenia rufa to the application of diferent amount of Urea, concentrated superphosphate and muriate of potash, in a sand 108m soil of farm located in Chaparral (Tolima at 1000 above sea level, 250C annual mean temperature, and 2.500mm annual mean precipitation. Box and Hunter's surface response model was usedas advised by the Instituto Agropecuario Colombiano.The regresion analysis shows that increasing applications levels of Nitrogen (urea and Phosphorus (superphosphate increase the amount of green forage and protein conten; highest level of forage 41 ton and protein 3.5% content were obtained using 400 and 200 kg.ha-1 of urea and superphosphate. From this information, the author recomend the use of amounts between 150

  6. Modelling and mutational analysis of Aspergillus nidulans UreA, a member of the subfamily of urea/H+ transporters in fungi and plants

    Science.gov (United States)

    Sanguinetti, Manuel; Amillis, Sotiris; Pantano, Sergio; Scazzocchio, Claudio; Ramón, Ana

    2014-01-01

    We present the first account of the structure–function relationships of a protein of the subfamily of urea/H+ membrane transporters of fungi and plants, using Aspergillus nidulans UreA as a study model. Based on the crystal structures of the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT) and of the Nucleobase-Cation-Symport-1 benzylhydantoin transporter from Microbacterium liquefaciens (Mhp1), we constructed a three-dimensional model of UreA which, combined with site-directed and classical random mutagenesis, led to the identification of amino acids important for UreA function. Our approach allowed us to suggest roles for these residues in the binding, recognition and translocation of urea, and in the sorting of UreA to the membrane. Residues W82, Y106, A110, T133, N275, D286, Y388, Y437 and S446, located in transmembrane helixes 2, 3, 7 and 11, were found to be involved in the binding, recognition and/or translocation of urea and the sorting of UreA to the membrane. Y106, A110, T133 and Y437 seem to play a role in substrate selectivity, while S446 is necessary for proper sorting of UreA to the membrane. Other amino acids identified by random classical mutagenesis (G99, R141, A163, G168 and P639) may be important for the basic transporter's structure, its proper folding or its correct traffic to the membrane. PMID:24966243

  7. Entry of blood urea into the rumen of the llama

    International Nuclear Information System (INIS)

    Hinderer, S.; Engelhardt, W. von

    1976-01-01

    Llamas were provided with a large rumen fistula, and the transfer of blood urea into the temporarily isolated rumen, cleaned and filled with test solution was measured. Plasma urea clearance due to transfer of blood urea across the rumen wall should indicate changes in its permeability to urea. Clearance values were highest with CO 2 or with high concentrations of butyric acid. Permeability was low when food was with-held and when no volatile fatty acids were present in the solution. The permeability of the rumen wall to blood urea can be altered significantly. These changes can affect blood urea transfer more extensively than changes in the plasma urea concentration within physiological ranges

  8. Alpha Resonant States in 13C

    International Nuclear Information System (INIS)

    Rodrigues, M. R. D.; Borello-Lewin, T.; Horodynski-Matsushigue, L. B.; Duarte, J. L. M.; Rodrigues, C. L.; Souza, M. A.; Miyake, H.; Cunsolo, A.; Cappuzzello, F.; Ukita, G. M.

    2011-01-01

    The 9 Be( 6 Li,d) 13 C reaction was used to investigate alpha resonant states in 13 C up to 15 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. An energy resolution of 50 keV was obtained. Several narrow alpha resonant states not previously measured were detected, in particular the one at the (3α+n) threshold populated by an L = 2 transfer, revealing a 9 Be+α component for the 1/2 - cluster state candidate at this threshold. Experimental angular distributions are presented in comparison with DWBA predictions.

  9. A methodological aspect of the {sup 14}C-urea breath test used in Helicobacter pylori diagnosis; Wybrany aspekt metodologiczny testu oddechowego z mocznikiem znakowanym stosowanego w diagnostyce zakazenia Helicobacter pylori

    Energy Technology Data Exchange (ETDEWEB)

    Kopanski, Z.; Niziol, J.; Micherdzinski, J.; Wasilewska-Radwanska, M.; Cienciala, A.; Lasa, J.; Witkowska, B. [Szpital Wojskowy, Cracow (Poland)]|[Institute of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Cracow (Poland)]|[Institute of Nuclear Physics, Cracow (Poland)

    1996-12-31

    The main purpose of those investigations was optimisation of the performing time of the breath test with {sup 14}C-labelled urea which reveals Helicobacter pylori infection. It was analysed 117 species, preselected according to endoscopy and histopathology results, 56 of them have suffered from chronic gastritis and 61 from gastric ulcer disease. Using microbiology diagnosis (culture + IFP test) it was found that 86 species were H. pylori infected. This group of patients were next subject to investigations with the breath test with {sup 14}C-labelled urea. Measurements of radioactivity of breathe air have been carried out for 30 minutes. The obtained results allow us to maintain that the optimal time of duration of the test described above is 30 minutes. (author) 38 refs, 2 tabs, 1 fig

  10. Water-mediated interactions between trimethylamine-N-oxide and urea.

    Science.gov (United States)

    Hunger, Johannes; Ottosson, Niklas; Mazur, Kamila; Bonn, Mischa; Bakker, Huib J

    2015-01-07

    The amphiphilic osmolyte trimethylamine-N-oxide (TMAO) is commonly found in natural organisms, where it counteracts biochemical stress associated with urea in aqueous environments. Despite the important role of TMAO as osmoprotectant, the mechanism behind TMAO's action has remained elusive. Here, we study the interaction between urea, TMAO, and water in solution using broadband (100 MHz-1.6 THz) dielectric spectroscopy. We find that the previously reported tight hydrogen bonds between 3 water molecules and the hydrophilic amine oxide group of TMAO, remain intact at all investigated concentrations of urea, showing that no significant hydrogen bonding occurs between the two co-solutes. Despite the absence of direct TMAO-urea interactions, the solute reorientation times of urea and TMAO show an anomalous nonlinear increase with concentration, for ternary mixtures containing equal amounts of TMAO and urea. The nonlinear increase of the reorientation correlates with changes in the viscosity, showing that the combination of TMAO and urea cooperatively enhances the hydrogen-bond structure of the ternary solutions. This nonlinear increase is indicative of water mediated interaction between the two solutes and is not observed if urea is combined with other amphiphilic solutes.

  11. Effect of replacing wheat bran with spineless cactus plus urea in ...

    African Journals Online (AJOL)

    Esnart Mukumbo

    2017-06-12

    Jun 12, 2017 ... When the aim is to potentiate rumen microbial protein synthesis with the use of ... Table 1 Chemical composition of sugarcane, corn, wheat bran and spineless ... These samples were stored at −15 °C for later urea analyses.

  12. Reingeniería de la geometría desconocida de engranajes cónicos con dientes rectos y curvilíneos.

    OpenAIRE

    G. González Rey; S. A. Marrero Osorio

    2008-01-01

    En el trabajo se presenta un procedimiento para dar solución al problema de solución inversa asociado con la determinación de la geometría desconocida del dentado de un engranaje cónico con ejes ortogonales y dientes de altura proporcional en base a cálculos de ingeniería de engranajes y con empleo de mediciones con herramientas de taller. El procedimiento propone un método práctico, con asistencia de un cálculo organizado linealmente y una búsqueda exhaustiva, para obtener los parámetros fun...

  13. Preparation of 15N-13C-fulminic acid

    International Nuclear Information System (INIS)

    Wilmes, R.; Winnewisser, M.

    1993-01-01

    The precursor for the title compound was prepared in a three-step synthesis. The 13 C-label was incorporated in the first step employing 2- 13 C-ethyl acetate and the 15 N-label in the last step, using 15 N-sodium nitrite. Upon pyrolysis the precursor forms three fragments, one of them being the title compound. (Author)

  14. Polymeric proanthocyanidins 13C NMR studies of procyanidins

    Science.gov (United States)

    Lawrence J. Porter; Roger H. Newman; Lai Yeap Foo; Herbert Wong; Richard W. Hemingway

    1982-01-01

    Proanthocyanidin polymers have been shown to consist entirely of flavan-3-ol units by a combination of techniques including 13C n.m.r. spectroscopy. The 13C n.m.r. spectra of the polymers and related molecules are now considered in more detail. Prior to this study UC n.m.r. data has been published of procyanidins and...

  15. Evaluation of carbon transfers in cattle and humans using 13C

    International Nuclear Information System (INIS)

    Masuda, Tsuyoshi; Tako, Yasuhiro; Nakamura, Yuji

    2010-01-01

    In the safety assessment made around the spent nuclear fuel reprocessing plant in Rokkasho, Aomori, among radioactive nuclides released from the plant, 14 C is expected to be the largest contributor to radiation dose received by the neighboring population through agricultural and dairy products. The objectives of this study are to clarify the transfer of 14 C from grass to beef and milk and its metabolism in the human body experimentally. (1) 13 C-labeled grass was fed for 28 days to beef cattle and cows. 13 C isotopic ratio was measured in serum and other samples including muscle of beef cattle and milk of dairy cow. The 13 C rations in milk, breath air, urine and feces decreased very rapidly within 3 day after cessation of the administration of 13 C-labeled feed. However, a slow decrease in 13 C ratio was observed in muscle and serum. (2) 13 C isotopic ratios were measured in breath air, urine, feces and serum over 16 weeks in humans who were orally administered of 13 C labeled leucine, palmitic acid, glucose, boiled rice and soymilk, respectively. Residual 13 C in their bodies experimentally observed were lower than the estimates by the ICRP metabolic model for organic carbon ingestion. (author)

  16. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component of articles intended for use in producing...

  17. Quantitative importance of the pentose phosphate pathway determined by incorporation of 13C from [2-13C]- and [3-13C]glucose into TCA cycle intermediates and neurotransmitter amino acids in functionally intact neurons

    DEFF Research Database (Denmark)

    Brekke, Eva Marie; Walls, Anne Byriel; Schousboe, Arne

    2012-01-01

    is known about the PPP in neurons. The activity of the PPP was quantified in cultured cerebral cortical and cerebellar neurons after incubation in the presence of [2-(13)C]glucose or [3-(13)C]glucose. The activity of the PPP was several fold lower than glycolysis in both types of neurons. While metabolism...

  18. BUN (Blood Urea Nitrogen): MedlinePlus Lab Test Information

    Science.gov (United States)

    ... https://medlineplus.gov/labtests/bunbloodureanitrogen.html BUN (Blood Urea Nitrogen) To use the sharing features on this ... please enable JavaScript. What is a BUN (Blood Urea Nitrogen) Test? A BUN, or blood urea nitrogen ...

  19. Urea-induced oxidative damage in Elodea densa leaves.

    Science.gov (United States)

    Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Prasad, M N V

    2015-09-01

    Urea being a fertilizer is expected to be less toxic to plants. However, it was found that urea at 100 mg L(-1) caused the oxidative stress in Elodea leaves due to the formation of reactive oxygen species (ROS) and lipid peroxidation that are known to stimulate antioxidant pathway. Urea at a concentration of 500 and 1000 mg L(-1) decreased low-molecular-weight antioxidants. In this case, the antioxidant status of plants was supported by the activity of antioxidant enzymes such as superoxide dismutase and guaiacol peroxidase. A significant increase in the soluble proteins and -SH groups was observed with high concentrations of urea (30-60 % of control). Thus, the increased activity of antioxidant enzymes, low-molecular-weight antioxidants, and induced soluble protein thiols are implicated in plant resistance to oxidative stress imposed by urea. We found that guaiacol peroxidase plays an important role in the removal of the peroxide in Elodea leaves exposed to 1000 mg L(-1)of urea.

  20. The effect of CP concentration in the diet on urea kinetics and microbial usage of recycled urea in cattle: a meta-analysis.

    Science.gov (United States)

    Batista, E D; Detmann, E; Valadares Filho, S C; Titgemeyer, E C; Valadares, R F D

    2017-08-01

    In ruminants, urea recycling is considered an evolutionary advantage. The amount of urea recycled mainly depends of the nitrogen (N) intake and the amount of organic matter (OM) digested in the rumen. Because recycled N contributes to meeting microbial N requirements, accurate estimates of urea recycling can improve the understanding of efficiency of N utilization and N losses to the environment. The objective of this study was to evaluate urea kinetics and microbial usage of recycled urea N in ruminants using a meta-analytical approach. Treatment mean values were compiled from 25 studies with ruminants (beef cattle, dairy cows and sheep) which were published from 2001 to 2016, totalling 107 treatment means. The data set was analyzed according to meta-analysis techniques using linear or non-linear mixed models, taking into account the random variations among experiments. Urea N synthesized in the liver (UER) and urea N recycled to the gut (GER) linearly increased (PCP concentration and the ratio of CP to digestible OM (CP:DOM). Maximum curvature analyses identified 17% dietary CP as the point where there was a prominent increase in hepatic synthesis of urea N, likely due to an excess of dietary N leading to greater ammonia absorption. The GER:UER decreased with increasing dietary CP concentration (PCP⩾19%, GER:UER reached near minimal values. The fraction of UER eliminated as urinary urea N and the contribution of urea N to total urinary N were positively associated with dietary CP (PCP was 17%. The fractions of GER excreted in the feces and utilized for anabolism decreased, whereas the fraction of GER returned to the ornithine cycle increased with dietary CP concentration (PCP and CP:DOM increased (PCP/kg DOM. The models obtained in this study contribute to the knowledge on N utilization, and they could be used in feeding models to predict urea recycling and thus to improve formulation of diets to reduce N losses that contribute to air and water pollution.

  1. Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates.

    Science.gov (United States)

    McNair, Laura F; Kornfelt, Rasmus; Walls, Anne B; Andersen, Jens V; Aldana, Blanca I; Nissen, Jakob D; Schousboe, Arne; Waagepetersen, Helle S

    2017-03-01

    Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few comparative characterization studies exist for acute hippocampal and cerebral cortical slices, hence, the aim of the current study was to characterize and compare glucose and acetate metabolism in these slice preparations in a newly established incubation design. Cerebral cortical and hippocampal slices prepared from 16 to 18-week-old mice were incubated for 15-90 min with unlabeled glucose in combination with [U- 13 C]glucose or [1,2- 13 C]acetate. Our newly developed incubation apparatus allows accurate control of temperature and is designed to avoid evaporation of the incubation medium. Subsequent to incubation, slices were extracted and extracts analyzed for 13 C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation media. Based on the measured 13 C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of 13 C-labeling observed with [U- 13 C]glucose in slices from cerebral cortex and hippocampus revealed no significant regional differences regarding glycolytic or total TCA cycle activities. On the contrary, results from the incubations with [1,2- 13 C]acetate suggest a higher capacity of the astrocytic TCA cycle in hippocampus compared to cerebral cortex. Finally, we propose a new approach for assessing compartmentation of metabolite pools between astrocytes and neurons using 13 C-labeling (%) data obtained from

  2. {sup 13}C relaxation in an RNA hairpin

    Energy Technology Data Exchange (ETDEWEB)

    King, G.C. [Univ. of South Wales, Kensington (Australia)]|[Rice Univ., Houston, TX (United States); Akratos, C. [Univ. of South Wales, Kensington (Australia); Xi, Z.; Michnica, M.J. [Rice Univ., Houston, TX (United States)

    1994-12-01

    This initial survey of {sup 13}C relaxation in the {triangle}TAR RNA element has generated a number of interesting results that should prove generally useful for future studies. The most readily comparable study in the literature monitored {sup 13}C relaxation of the methyl groups from unusual bases in tRNA{sup Phe}. The study, which used T{sub 1} and NOE data only, reported order parameters for the methyl group axis that ranged between 0.51 and 0.97-a range similar to that observed here. However, they reported a breakdown of the standard order parameter analysis at higher (118-MHz {sup 13}C) frequencies, which should serve to emphasize the need for a thorough exploration of suitable motional models.

  3. Vivencias psicosociales reveladas por niños que reciben tratamiento con quimioterapia por cáncer

    OpenAIRE

    BLANCA CECILIA VANEGAS DE AHOGADO; MARÍA ELVIRA BELTRÁN HERRERA; VIVIANA CIFUENTES GIL; YULIETH ALEJANDRA DUARTE; JIMMY JULIÁN MONTOYA; JOHANNA MARCELA RIVERA ZABALA; MARÍA MERCEDES LAFAURIE VILLAMIL

    2009-01-01

    Se realizó un estudio cualitativo con el propósito de descubrir las vivencias psicosociales de niños y niñas de 9 a 12 años que recibían tratamiento con quimioterapia por cáncer. La recolección de la información se hizo mediante encuentros lúdicos con el apoyo de algunas preguntas básicas que facilitaron las revelaciones narrativas. Tres aspectos se destacan en los hallazgos del estudio: vivencias desfavorables, vivencias relacionadas con la autoestima y vivencias favorables; las dos primeras...

  4. Cuidador familiar del niño con cáncer: un rol en transición

    OpenAIRE

    Sonia Carreño-Moreno; Lorena Chaparro- Díaz; Paola Blanco-Sánchez

    2017-01-01

    El objetivo de este artículo es integrar los hallazgos derivados de investigación que evidencian que el ser cuidador de un niño con cáncer denota un rol en transición. La metodología que se empleó fue la revisión integrativa de literatura que incluyó la búsqueda sistemática de esta, una lectura crítica de las publicaciones, la integración de hallazgos con apoyo en Atlas Ti ver- sión 7, en un proceso de comparación constante. Pudo ¿verse que el cuidador del niño con cán - cer ...

  5. Freshwater Mussel Shell δ13C Values as a Proxy for δ13CDIC in a Polluted, Temperate River

    Science.gov (United States)

    Graniero, L. E.; Gillikin, D. P.; Surge, D. M.

    2017-12-01

    Freshwater mussel shell δ13C values have been examined as an indicator of ambient δ13C composition of dissolved inorganic carbon (DIC) in temperate rivers. However, shell δ13C values may be obscured by the assimilation of respired, metabolic carbon (CM) derived from the organism's diet. Water δ18O and δ13CDIC values were collected fortnightly from August 2015 through July 2017 from three sites (one agricultural, one downstream of a wastewater treatment plant, one urban) in the Neuse River, NC to test the reliability of Elliptio complanata shell δ13C values as a proxy for δ13CDIC values. Muscle, mantle, gill, and stomach δ13C values were analyzed to approximate the %CM incorporated into the shell. All tissue δ13C values were within 2‰ of each other, which equates to a ±1% difference in calculated %CM. As such, muscle tissue δ13C values will be used for calculating the %CM, because they have the slowest turnover rate of the tissues sampled. Water temperature and δ18O values were used to calculate predicted aragonite shell δ18O­ values (δ18O­ar) based on the aragonite-water fractionation relationship. To assign dates to each shell microsample, predicted δ18O­ar values were compared to high-resolution serially sampled shell values. Consistent with previous studies, E. complanata cease growth in winter when temperatures are below about 12ºC. Preliminary results indicate that during the growing season, shell δ13C values are lower than expected equilibrium values, reflecting the assimilation of 15% CM, on average. Shell δ13C values are not significantly different than δ13CDIC values, but do not capture the full range of δ13CDIC values during each growing season. Thus, δ13C values of E. complanata shells can be used to reliably reconstruct past δ13CDIC values within 2‰ of coeval values. Further research will investigate how differing land-use affects the relationship between shell δ13C, CM, and δ13CDIC values.

  6. Nutritional factors influencing milk urea in buffaloes

    Directory of Open Access Journals (Sweden)

    V. Proto

    2011-03-01

    Full Text Available Urea is the primary form in which N is excreted in ruminants. Milk urea (MU content was introduced as a means to monitor the efficiency of protein utilisation in dairy cattle (Baker et al., 1995; Roseler et al., 1993; Bertoni, 1995. In this study the effect of some nutrition factors on MU content in buffalo herds was analysed in order to examine the possibility that protein nutrition could be monitored by means of milk urea at herd level........

  7. Ansiedad y depresión en mujeres con cáncer de mama en radioterapia: Prevalencia y factores asociados

    OpenAIRE

    Ornelas-Mejorada,Rosa Elena; Tufiño Tufiño,Mónica Anahí; Sánchez-Sosa,Juan José

    2011-01-01

    Someterse a radioterapia y padecer los efectos secundarios son situaciones que generan ansiedad y depresión en las mujeres con cáncer de mama. El objetivo fue evaluar la prevalencia de ansiedad y depresión que presentan las mujeres con cáncer de mama en radioterapia y analizar los efectos y las diferencias de variables clínicas y sociodemográficas sobre su malestar psicológico. Participaron 203 mujeres mexicanas con cáncer de mama en estadios 0-III. Para evaluar ansiedad y depresión se utiliz...

  8. comparative studies on the mineralization of furfural urea and urea

    African Journals Online (AJOL)

    DR. AMINU

    2013-12-02

    Dec 2, 2013 ... In this research, laboratory studies were conducted to evaluate the effects of furfural urea as a slow release N ... regarding groundwater pollution ( Myrold, 2008). The ... The plastic pots containing the treated soil sample and.

  9. The effect of urea with urease inhibitors and urea on yield and nitrate content in potato tubers

    Directory of Open Access Journals (Sweden)

    Karel Drápal

    2013-01-01

    Full Text Available The three-year field trial was established on two localities – Žabčice and Valečov in 2010–2012. Seven variants of nitrogen fertilization in four replications have been involved in this experiment – 100% of urea (U, 80% of urea, 60% of urea, 100% of UreaStabil (US, 80% of UreaStabil and 60% of UreaStabil, whilst 100% corresponded to 90 kg N.ha−1 after subtracting the content of Nmin in the soil, and the control variant without fertilization by mineral nitrogen. The two varieties with different lengths of vegetation periods have been chosen for the experiment – the early variety Karin and the mid-early variety Red Anna. In all cases, samples for the yield and qualitative analyses have been taken according to the phenological phase – the beginning of physiological maturity. The obtained results show that the highest average yield has been achieved in the variant of 100% of urea – 40.95 t. ha−1, the yield of this variant was statistically significantly higher than the yield of the other variants of fertilization (P < 0.05. Variants treated by urea without the urease inhibitor reached an average yield of 37.62 t.ha−1. However, this yield was not statistically significantly higher when comparing to the urea with the urease inhibitor (P > 0.05. In regard to localities, a relatively high average yield (44.58 t.ha−1 has been achieved on a characteristically potato-growing locality Valečov. This yield was statistically significantly higher than the one attained on the Žabčice locality (P < 0.05. In respect to varieties, the mid-early variety Red Anna attained a higher average yield (39.65 t. ha−1. Likewise, this yield was statistically significantly higher than the one of the early variety Karin (P < 0.05. The best year was 2012, in which the average yield of 38.73 t.ha−1 was achieved. This yield was statistically significantly higher than the yield of the year 2010 (P < 0.05. As far as nitrates are concerned, the

  10. Investigations of the influence of the content of crude plant protein in the ration on the utilisation of urea in dairy cattle. 3. Incorporation of /sup 15/N from urea into ruminal bacteria and protozoa

    Energy Technology Data Exchange (ETDEWEB)

    Tarakanow, B.W. (Allunionsinstitut fuer Physiologie, Biochemie und Ernaehrung landwirtschaftlicher Tiere, Borowsk (USSR)); Sommer, A. (Inst. fuer Tierproduktion, Nitra (Czechoslovakia)); Voigt, J. (Akademie der Landwirtschaftswissenschaften der DDR, Dummerstorf-Rostock. Forschungszentrum fuer Tierproduktion)

    The rations contained 10.7 (I), 13.7 (II) and 17.1 (III)% plant crude protein and, after the supplementation of 150 g urea per animal and day, a total of 13.8 (I), 16.7 (II) and 20.2 (III)% crude protein in the dry matter. The starch content and the dry matter was 25.6, 19.6 and 13.4% from I to III. The urea was intraruminally infused during the feeding in the morning and the evening. Samples were taken from the rumen up to 72 h after intake. 4, 8 and 12 hours after /sup 15/N intake 100 ml rumen fluid contained 2.5, 3.3 and 3.0 (I), 3.1, 3.0 and 2.8 (II) and 4.1, 4.4 and 4.2 (III) g dry matter of the bacteria and 7.9, 9.0 and 5.9 (I), 3.8, 3.2 and 3.1 (II) and 2.1, 3.1 and 1.7 (III) g dry matter of the protozoa. In comparison to I the concentration of microbes in III decreased to 60-67%. The N level of the ration did not influence the N and carbohydrate content of the microbes as well as the amino acid composition of the microbial protein. Level and dynamics of /sup 15/N incorporation differed between protozoa and bacteria. From I to III the maximum labelling degrees were 3.27, 3.09 and 1.98 for bacteria and 0.93, 0.82 and 0.80 atom-% /sup 15/N excess. The apparent half life of /sup 15/N on 10...12 h in the bacteria N and of 34...59 h in the protozoa N showed that /sup 15/N metabolism in protozoa is distinctly slower. The /sup 15/N frequency in the amino acids (AA) of the microbial protein revealed that urea N was included in the synthesis of all the 16 AA investigated, with big differences in the relative /sup 15/N frequency in the AA both within the microbes and between the species of microbes. One can conclude that the decreasing utilization of /sup 15/N from urea in comparison with that of the total N is caused by the reduction of the concentration of microbes in the rumen fluid and the relatively lower quota of the incorporation of urea N into bacteria N.

  11. Phase transitions in the urea/n-nonadecane system by calorimetric techniques

    International Nuclear Information System (INIS)

    Lopez-Echarri, A; Ruiz-Larrea, I; Fraile-RodrIguez, A; Diaz-Hernandez, J; Breczewski, T; Bocanegra, E H

    2007-01-01

    A calorimetric study of urea/n-nonadecane, CO(NH 2 ) 2 /C 19 H 40 , and the deuterated derivatives, CO(ND 2 ) 2 /C 19 D 40 and CO(NH 2 ) 2 /C 19 D 40 , around the structural phase transition temperature is presented. For this purpose differential scanning (DSC), temperature-modulated (AC) and adiabatic calorimetry have been used and the obtained results are compared. Leaving apart the noticeable peak associated with the main phase transition at 158.5, 149.4 and 154 K respectively, small anomalies of the specific heat are found at lower temperatures and their corresponding entropic and enthalpic changes are reported. Heating and cooling experiments show the influence of the temperature rate and the thermal history on the detailed profile of the specific heat traces. The presence of thermal hysteresis and latent heat as a way to characterize the order of the phase transitions is discussed. Finally, a tentative approach to the urea and the alkyl chain contributions to the specific heat and their influence on the phase transition mechanisms is presented

  12. Biosynthesis of quinolizidine alkaloids. Incorporation of [1-amino-15N, 1-13C] cadaverine into lupanine, 13-hydroxylupanine, and angustifoline

    International Nuclear Information System (INIS)

    Rana, J.; Robins, D.J.

    1985-01-01

    The labelling patterns in (+)-lupanine, (+)-13-hydroxylupanine, and (+)-angustifoline derived biosynthetically from [1-amino- 15 N,1- 13 C]-1,5-diaminopentane (cadaverine) have been established by 13 C n.m.r. spectroscopy. Three cadaverine units are incorporated to about the same extent into each of these three alkaloids. The presence of two doublets due to 13 C- 15 N coupling in the 13 C brace 1 H brace n.m.r. spectra associated with C-2 and C-15 of lupanine and 13-hydroxylupanine, and one 13 C- 15 N doublet at C-2 of angustifoline, indicate that two of the cadaverine units are converted into the outer rings of the tetracyclic quinolizidine alkaloids in a specific fashion. (author)

  13. Study on the concentration of unsaturated fatty acid methyl esters by urea complexation

    International Nuclear Information System (INIS)

    Jiang, B.; Liu, Y.

    2014-01-01

    This study was done to obtain concentrated unsaturated fatty acid methyl esters (FAME) by urea complexation from soybean derived FAME. Effects of urea-to-FAME ratio, 95% ethanol-to-FAME ratio, crystallization temperature and time on the purification of unsaturated FAME were investigated through single factor experiments. Optimum conditions to obtain maximum FAME yield of NUCF with the purity of unsaturated FAME greater than 98% were established using Box-Behnken design (BBD) method and response surface methodology (RSM). Under optimal conditions, the FAME yield was 58.08%, and the purity of unsaturated FAME was 98% at a urea-to-FAME ratio of 1.23, 95% ethanol-to-FAME ratio of 7 and crystallization temperature of 0 degree C. Verification results revealed that the predicted values were reasonably close to experimentally observed values of 56.93% and 98.01%. (author)

  14. Sintomatología depresiva y calidad de vida en pacientes mujeres con cáncer de mama

    Directory of Open Access Journals (Sweden)

    Rubén Valle

    2006-10-01

    Full Text Available Introducción: Las pacientes con cáncer de mama tienden a desarrollar algún tipo de trastorno psiquiátrico, principalmente depresión. Una manera de evaluar cómo las pacientes conllevan su enfermedad es a través de la calidad de vida. Objetivos: Determinar la prevalencia de sintomatología depresiva y calidad de vida y sus asociaciones con el tiempo desde el diagnóstico y el estado menopáusico. Diseño: Estudio analítico, observacional y transversal. Lugar: Servicio de Oncología del Hospital Arzobispo Loayza. Participantes: Mujeres con diagnóstico clínico e histológico de cáncer de mama que acudieron para tratamiento con quimioterapia. Intervenciones: Se utilizó el inventario de depresión de Beck, la escala de calidad de vida de Mezzich y Cohen y un cuestionario demográfico. El análisis fue realizado con la prueba exacta de Fisher, t de student y regresión lineal. Principales medidas de resultados: Sintomatología depresiva, calidad de vida. Resultados: Se encuestó 24 pacientes, encontrándose una prevalencia de 38% de sintomatología depresiva y 38% de baja calidad de vida. No se halló asociación significativa de sintomatología depresiva y nivel de calidad de vida con alguno de los factores asociados, excepto en la relación de este último con el grado de instrucción de la paciente, con un OR de 11,2 (p= 0,047, IC 95% 0,99 a 125,6. Conclusiones: Se encontró una prevalencia de 38% de sintomatología depresiva y 38% de baja calidad de vida. El tiempo desde el diagnóstico y estado menopáusico no tuvieron una asociación significativa con la sintomatología depresiva y la calidad de vida. El único factor asociado significativamente con la calidad de vida fue el grado de instrucción.

  15. (13)C enrichment of the CO2 in breast milk and in the breath is rapidly modified by changes in the (13)C content of the diet.

    Science.gov (United States)

    Villalpando, Salvador; Del Prado, Martha; Cienfuego, Edith; Morales, Pedro

    2014-01-01

    C4 plants (e.g. corn and sugar cane) have greater (13)C enrichment than C3 plants (e.g. wheat and sugar beet). To assess whether (13)C enrichment of CO2 in the breath and breast milk of women on diets based on C3 and C4 foods changes from one diet to the other. Six breast-feeding women were studied at 5-6 months postpartum. They ate a controlled C4 diet on days 1 and 2 followed by a C3 diet on days 3 and 4. Diet duplicates, breast milk on days 2 and 4 and hourly breath samples were collected over 4 days. (13)C enrichment was measured by isotope-ratio mass spectrometry. Values of δ(13)C were calculated from the international PDBV standard (δ(13)CPDBV). Differences between means were compared by paired t test or t test for repeated measurements. δ(13)CPDBV values were significantly higher in the C4 diet than in the C3 diet composites (p value was greater on days 1 and 2 (range -15.4 to -13.2, respectively) and declined on days 3 and 4 (range -20.0 to -21.8, respectively, p value in the breath and breast milk fractions, which diminish rapidly on a C3 diet. Further studies focusing on individual nutrients are warranted.

  16. Hyperhomocysteinemia and methylenetetrahydrofolate reductase 677C→T and 1298A→C mutations in patients with inflammatory bowel disease Hiperhomocisteinemia y mutaciones de la metilentetrahidrofolato reductasa 677C→T y 1298A→C en pacientes con enfermedad inflamatoria intestinal

    Directory of Open Access Journals (Sweden)

    C. Fernández-Miranda

    2005-07-01

    Full Text Available Background: hyperhomocysteinemia has been recently described in patients with inflammatory bowel disease (IBD, that could be related to the increased risk for thrombosis that exists in this disease. The aim of this study was the assessment of hyperhomocysteinemia in patients with IBD and its relation among vitamin B12 and folate levels, and methylenetetrahydrofolate reductase (MTHFR 677C→ T and 1298A→C mutations. Patients and methods: fifty two consecutive patients with IBD were studied (29 women and 23 men; age: mean (standard deviation 41.7 [11.9] years and 186 controls with no difference in age and gender. Hyperhomocysteinemia was considered as homocysteine levels higher than mean plus two standard deviations of the control group (≥ 13 μmol/l. Results: patients had an elevated prevalence of hyperhomocysteinemia (17.3 vs. 3.7%; p = 0.002 and lower folate (7.6 [4.1] vs. 8.9 [3.7] ng/ml; p = 0.01 and B12 vitamin levels (499 [287] vs. 603 [231] pg/ml; p = 0.003. Homocysteinemia was higher (14.3 [5.8] vs. 9.1 [3.9] μmol/l; p = 0.006 in 6 patients (11.5% that had suffered thromboembolism. Frequency of MTHFR 677C→T (13.5 vs. 11.3%; p = 0.66 and 1298A→C (7.8 vs. 7.0%; p = 0.76 mutations was not increased in patients. Odds ratio (OR for IBD in hyperhomocysteinemic patient was 5.51, 95% confidence interval (CI, 1.81-16.76; p = 0.002. Hyperhomocysteinemia was negatively associated with feminine gender (OR 0.08, 95% CI 0.01-0.49; p = 0.006 and folate levels (OR 0.04, 95%CI: 0.007-0.20; p Fundamento: recientemente se ha descrito la existencia de hiperhomocisteinemia en la enfermedad inflamatoria intestinal (EII, que podría estar relacionada con el mayor riesgo de trombosis en esta enfermedad. El objetivo del estudio ha sido evaluar la hiperhomocisteinemia en los pacientes con EII y su relación con las concentraciones de vitamina B12 y folato séricos y con las mutaciones de la metilentetrahidrofolato reductasa (MTHFR 677C→T y 1298A→C

  17. Urea immunoliposome inhibits human vascular endothelial cell proliferation for hemangioma treatment

    Science.gov (United States)

    2013-01-01

    Background Urea injection has been used in hemangioma treatment as sclerotherapy. It shrinks vascular endothelial cells and induces degeneration, necrosis, and fibrosis. However, this treatment still has disadvantages, such as lacking targeting and difficulty in controlling the urea dosage. Thus, we designed a urea immunoliposome to improve the efficiency of treatment. Methods The urea liposome was prepared by reverse phase evaporation. Furthermore, the urea immunoliposome was generated by coupling the urea liposome with a vascular endothelial growth factor receptor (VEGFR) monoclonal antibody using the glutaraldehyde cross-linking method. The influence of the urea immunoliposome on cultured human hemangioma vascular endothelial cells was observed preliminarily. Results Urea immunoliposomes showed typical liposome morphology under a transmission electron microscope, with an encapsulation percentage of 54.4% and a coupling rate of 36.84% for anti-VEGFR. Treatment with the urea immunoliposome significantly inhibited the proliferation of hemangioma vascular endothelial cells (HVECs) in a time- and dose-dependent manner. Conclusions The urea immunoliposome that we developed distinctly and persistently inhibited the proliferation of HVECs and is expected to be used in clinical hemangioma treatment. PMID:24266957

  18. Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

    Directory of Open Access Journals (Sweden)

    Das G

    2015-08-01

    Full Text Available Gautam Das, Hyon Hee Yoon Department of Chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-do, South Korea Abstract: An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 µA·cm-2·mM-1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. Keywords: electrochemical deposition, sulfonated graphene oxide, urease

  19. The crystal structure of urea nitrate

    NARCIS (Netherlands)

    Harkema, Sybolt; Feil, D.

    1969-01-01

    The structure of urea nitrate has been solved, by the use of three-dimensional X-ray data. Data were collected using Cu Ke and Mo K0~ radiations. The structure consists of layers with urea and nitrate groups held together by hydrogen bonds. The positions of all hydrogen atoms were found. The final R

  20. The 12C/13C ratio in stellar atmospheres. VI. Five luminous cool stars

    International Nuclear Information System (INIS)

    Hinkle, K.H.; Lambert, D.L.; Snell, R.L.

    1976-01-01

    The isotopic abundance ratio, 12 C/ 13 C, is derived from the CO vibration rotation lines at 1.6 and 2.3 μ for five cool luminous stars by a simple curve-of-growth technique. A new analysis of CN lines at 8000 A is also described for α Sco and α Ori. Results derived independently from CO and CN are in agreement. Final results are 12 C/ 13 C=7 +- 2(α Ori), 12 +- 3(α Sco), 7 +- 3(β Peg), 25 +- 7(chi Cyg), 17 +- 4(α Her), and 7 +- 1.5(α Boo). The α Boo analysis provides a check on the CO curve-of-growth technique; the 12 C/ 13 C ratio from the 2.3 μ CO lines is in good agreement with the previously determined ratio from CN and CH lines

  1. Origins of protein denatured state compactness and hydrophobic clustering in aqueous urea: inferences from nonpolar potentials of mean force.

    Science.gov (United States)

    Shimizu, Seishi; Chan, Hue Sun

    2002-12-01

    Free energies of pairwise hydrophobic association are simulated in aqueous solutions of urea at concentrations ranging from 0-8 M. Consistent with the expectation that hydrophobic interactions are weakened by urea, the association of relatively large nonpolar solutes is destabilized by urea. However, the association of two small methane-sized nonpolar solutes in water has the opposite tendency of being slightly strengthened by the addition of urea. Such size effects and the dependence of urea-induced stability changes on the configuration of nonpolar solutes are not predicted by solvent accessible surface area approaches based on energetic parameters derived from bulk-phase solubilities of model compounds. Thus, to understand hydrophobic interactions in proteins, it is not sufficient to rely solely on transfer experiment data that effectively characterize a single nonpolar solute in an aqueous environment but not the solvent-mediated interactions among two or more nonpolar solutes. We find that the m-values for the rate of change of two-methane association free energy with respect to urea concentration is a dramatically nonmonotonic function of the spatial separation between the two methanes, with a distance-dependent profile similar to the corresponding two-methane heat capacity of association in pure water. Our results rationalize the persistence of residual hydrophobic contacts in some proteins at high urea concentrations and explain why the heat capacity signature (DeltaC(P)) of a compact denatured state can be similar to DeltaC(P) values calculated by assuming an open random-coil-like unfolded state. Copyright 2002 Wiley-Liss, Inc.

  2. Conditions to obtain precise and true measurements of the intramolecular {sup 13}C distribution in organic molecules by isotopic {sup 13}C nuclear magnetic resonance spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, Kevin [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Gilbert, Alexis [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth–Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Julien, Maxime [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Yamada, Keita [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Silvestre, Virginie; Robins, Richard J.; Akoka, Serge [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth–Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Remaud, Gérald S., E-mail: gerald.remaud@univ-nantes.fr [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France)

    2014-10-10

    Highlights: • Evaluation of the trueness and precision criteria of isotopic {sup 13}C NMR spectrometry. • Use of bi-labelled [1,2-{sup 13}C{sub 2}]acetic acid to determine the performance of the instrumental response. • Inter-calibration of the {sup 13}C intramolecular composition of acetic acid using the technique GC-Py–irm-MS. - Abstract: Intramolecular {sup 13}C composition gives access to new information on the (bio) synthetic history of a given molecule. Isotopic {sup 13}C NMR spectrometry provides a general tool for measuring the position-specific {sup 13}C content. As an emerging technique, some aspects of its performance are not yet fully delineated. This paper reports on (i) the conditions required to obtain satisfactory trueness and precision for the determination of the internal {sup 13}C distribution, and (ii) an approach to determining the “absolute” position-specific {sup 13}C content. In relation to (i), a precision of <1% can be obtained whatever the molecule on any spectrometer, once quantitative conditions are met, in particular appropriate proton decoupling efficiency. This performance is a prerequisite to the measurement of isotope fractionation either on the transformed or residual compound when a chemical reaction or process is being studied. The study of the trueness has revealed that the response of the spectrometer depends on the {sup 13}C frequency range of the studied molecule, i.e. the chemical shift range. The “absolute value” and, therefore, the trueness of the {sup 13}C NMR measurements has been assessed on acetic acid and by comparison to the results obtained on the fragments from COOH and CH{sub 3} by isotopic mass spectrometry coupled to a pyrolysis device (GC-Py–irm-MS), this technique being the reference method for acetic acid. Of the two NMR spectrometers used in this work, one gave values that corresponded to those obtained by GC-Py–irm-MS (thus, the “true” value) while the other showed a bias, which was

  3. LA POLÍTICA EDUCATIVA CON RESPECTO A LOS LIBROS DE TEXTO Y LAS BIBLIOTECAS ESCOLARES EN LA EDUCACIÓN PRIMARIA PÚBLICA COSTARRICENSE, 1994-2010: ANÁLISIS HERMENÉUTICO-CRÍTICO

    Directory of Open Access Journals (Sweden)

    Marcela Gil Calderón

    2012-01-01

    Full Text Available En este ensayo se analiza la política educativa con respecto a los libros de texto y a las bibliotecas escolares, desde la hermenéutica crítica. Para ello se realizó una revisión bibliográfica de documentos producidos durante el periodo comprendido entre 1994-2010, en la enseñanza primaria pública costarricense. Después del análisis realizado, se concluye que la política educativa con respecto a los libros de texto, ha estado plagada de inconsistencias, entre lo que se dice y lo que se hace. En lo que respecta a las bibliotecas escolares, éstas han formado parte de este devenir de politización, por lo que a la fecha, a pesar de los grandes esfuerzos que realizan tanto el Departamento de Bibliotecas Escolares y Centros de Recursos para el Aprendizaje del Ministerio de Educación Pública, como los bibliotecólogos que tienen a cargo estas Bibliotecas Escolares y Centros de Recursos, no logran alcanzar con verdadero éxito su función dentro del contexto escolar. Para que esto se dé realmente, debe existir un verdadero modelo educativo, con una política educativa de largo aliento, que concatene claramente todos los elementos necesarios para así alcanzar una educación de calidad. Para ello es urgente la incorporación de las bibliotecas escolares como parte del sistema educativo, de manera que el profesional en bibliotecología, de manera coordinada con el docente y la docente, aporte para la formación de colecciones de materiales educativos, que respondan adecuadamente a la formación, recreación e información de los estudiantes.

  4. Hyperpolarized C-13 MRS Cardiac Metabolism Studies in Pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Hartwig, V.; Frijia, F.

    2012-01-01

    Cardiac metabolism assessment with hyperpolarized 13C magnetic resonance spectroscopy in pig models requires the design of dedicated coils capable of providing large field of view with high signal-to-noise ratio (SNR) data. This work presents a comparison between a commercial 13C quadrature...

  5. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    International Nuclear Information System (INIS)

    Fang, Weizhen; Zeng, Xingrong; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-01-01

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and 1 H nuclear magnetic resonance spectrometry ( 1 H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization

  6. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Weizhen; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-04-10

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and {sup 1}H nuclear magnetic resonance spectrometry ({sup 1}H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization.

  7. Effect of urea-supplemented diets on the ruminal bacterial and archaeal community composition of finishing bulls.

    Science.gov (United States)

    Zhou, Zhenming; Meng, Qingxiang; Li, Shengli; Jiang, Lan; Wu, Hao

    2017-08-01

    In this study, we evaluated the effects of urea-supplemented diets on the ruminal bacterial and archaeal communities of finishing bulls using sequencing technology. Eighteen bulls were fed a total mixed ration based on maize silage and concentrate (40:60) and randomly allocated to one of three experimental diets: a basal diet with no urea (UC, 0%), a basal diet supplemented with low urea levels (UL, 0.8% dry matter (DM) basis), and a basal diet supplemented with high urea levels (UH, 2% DM basis). All treatments were iso-nitrogenous (14% crude protein, DM basis) and iso-metabolic energetic (ME = 11.3 MJ/kg, DM basis). After a 12-week feeding trial, DNA was isolated from ruminal samples and used for 16S rRNA gene amplicon sequencing. For bacteria, the most abundant phyla were Firmicutes (44.47%) and Bacteroidetes (41.83%), and the dominant genera were Prevotella (13.17%), Succiniclasticum (4.24%), Butyrivibrio (2.36%), and Ruminococcus (1.93%). Urea supplementation had no effect on most phyla (P > 0.05), while there was a decreasing tendency in phylum TM7 with increasing urea levels (P = 0.0914). Compared to UC, UH had lower abundance of genera Butyrivibrio and Coprococcus (P = 0.0092 and P = 0.0222, respectively). For archaea, the most abundant phylum was Euryarchaeota (99.81% of the sequence reads), and the most abundant genus was Methanobrevibacter (90.87% of the sequence reads). UH increased the abundance of genus Methanobrevibacter and Methanobacterium (P = 0.0299 and P = 0.0007, respectively) and decreased the abundance of vadinCA11 (P = 0.0151). These findings suggest that urea-supplemented diets were associated with a shift in archaeal biodiversity and changes in the bacterial community in the rumen.

  8. θ13PMNS=θC/√(2) from GUTs

    International Nuclear Information System (INIS)

    Antusch, Stefan; Gross, Christian; Maurer, Vinzenz; Sluka, Constantin

    2013-01-01

    The recent observations of the leptonic mixing angle θ 13 PMNS are consistent with θ 13 PMNS =θ C /√(2) (with θ C being the Cabibbo angle θ 12 CKM ). We discuss how this relation can emerge in Grand Unified Theories (GUTs) via charged lepton corrections. The key ingredient is that in GUTs the down-type quark Yukawa matrix and the charged lepton Yukawa matrix are generated from the same set of GUT operators, which implies that the resulting entries are linked and differ only by group-theoretical Clebsch factors. This allows a link θ 12 e ≈θ C to be established, which can induce θ 13 PMNS ≈θ C /√(2) provided that the 1–3 mixing in the neutrino mass matrix is much smaller than θ C . We find simple conditions under which θ 13 PMNS ≈θ C /√(2) can arise via this link in SU(5) GUTs and Pati–Salam models. We also discuss possible corrections to the exact relation. Using lepton mixing sum rules different neutrino mixing patterns can be distinguished by their predictions for the Dirac CP phase δ PMNS .

  9. A lower limit on the surface C-12/C-13 ratio in Alpha Orionis

    Science.gov (United States)

    Gautier, T. N., III; Fink, U.; Larson, H. P.; Thompson, R. I.

    1976-01-01

    The second overtone CO bands near 1.6 microns were analyzed in Alpha Ori using synthetic spectra. No firm identification of (C-13)O was made, which allowed a lower limit of 20 to be set on the C-12/C-13 ratio. A rather low microturbulent velocity of 2 km/s was found to match the spectrum of Alpha Ori best.

  10. In vitro fermentation and chemical constituents of urea-molasses feed

    African Journals Online (AJOL)

    This study was carried out to assess the chemical contents, in vitro break down, volatile fatty acids, NH3¬-N and methane concentration of urea- molasses feed - block (UMFB) using different binders. Four feed - blocks were formulated as: UMFB A (Cement only), UMFB B (cement + clay), UMFB C (cement + cassava starch), ...

  11. Evaluation of [14C] and [13C]Sucrose as Blood-Brain Barrier Permeability Markers.

    Science.gov (United States)

    Miah, Mohammad K; Chowdhury, Ekram A; Bickel, Ulrich; Mehvar, Reza

    2017-06-01

    Nonspecific quantitation of [ 14 C]sucrose in blood and brain has been routinely used as a quantitative measure of the in vivo blood-brain barrier (BBB) integrity. However, the reported apparent brain uptake clearance (K in ) of the marker varies widely (∼100-fold). We investigated the accuracy of the use of the marker in comparison with a stable isotope of sucrose ([ 13 C]sucrose) measured by a specific liquid chromatography-tandem mass spectrometry method. Rats received single doses of each marker, and the K in values were determined. Surprisingly, the K in value of [ 13 C]sucrose was 6- to 7-fold lower than that of [ 14 C]sucrose. Chromatographic fractionation after in vivo administration of [ 14 C]sucrose indicated that the majority of the brain content of radioactivity belonged to compounds other than the intact [ 14 C]sucrose. However, mechanistic studies failed to reveal any substantial metabolism of the marker. The octanol:water partition coefficient of [ 14 C]sucrose was >2-fold higher than that of [ 13 C]sucrose, indicating the presence of lipid-soluble impurities in the [ 14 C]sucrose solution. Our data indicate that [ 14 C]sucrose overestimates the true BBB permeability to sucrose. We suggest that specific quantitation of the stable isotope ( 13 C) of sucrose is a more accurate alternative to the current widespread use of the radioactive sucrose as a BBB marker. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  12. Catalytic dehydration of ethanol for poly 13 C compounds synthesis

    International Nuclear Information System (INIS)

    Almasan, Valer; Marginean, Petru; Lazar, Mihaela; Tusa, Florina

    2003-01-01

    Classical methods for the synthesis of organic compounds are not very well applied in the case of 13 C labeled compounds. One of the principal demands is to find the best method to transform a small quantity of isotopic reagent with a very high yield. In this case to obtain 13 C 2 chloroethanol from 13 C 2 ethanol there are two synthesis steps: - catalytic dehydration of ethanol to ethylene; - ethylene double bounding saturation: either via ethylene oxide (30% yield) or in diluted solution of chlorine. For the first step of synthesis we choose the thermal dehydration over alumina catalyst at 400 deg C. There were tested 2 samples of g alumina with 255 m 2 /g and 355 m 2 /g with very good results. In the second step of the synthesis we used the chlorine addition to ethylene in very diluted water solution. We have built a reactor which combined the two steps of this synthesis method to produce 13 C 2 chloroethanol from 13 C 2 ethanol. The global yield of method was 42%. (authors)

  13. Urea thermolysis and NOx reduction with and without SCR catalysts

    International Nuclear Information System (INIS)

    Fang, Howard L.; DaCosta, Herbert F.M.

    2003-01-01

    Urea-selective catalytic reduction (SCR) has been a leading contender for removal of nitrogen oxides (deNO x ) from diesel engine emissions. Despite its advantages, the SCR technology faces some critical detriments to its catalytic performance such as catalyst surface passivation (caused by deposit formation) and consequent stoichiometric imbalance of the urea consumption. Deposit formation deactivates catalytic performance by not only consuming part of the ammonia produced during urea decomposition but also degrading the structural and thermal properties of the catalyst surface. We have characterized the urea thermolysis with and without the urea-SCR catalyst using both spectroscopic (DRIFTS and Raman) and thermal techniques (thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC)) to identify the deposit components and their corresponding thermal properties. Urea thermolysis exhibits two decomposition stages, involving ammonia generation and consumption, respectively. The decomposition after the second stage leads to the product of melamine complexes, (HNC=NH) x (HNCO) y , that hinder catalytic performance. The presence of catalyst accompanied with a good spray of the urea solution helps to eliminate the second stage. In this work, kinetics of the direct reduction of NO x by urea is determined and the possibility of using additives to the urea solution in order to rejuvenate the catalyst surface and improve its performance will be discussed

  14. Pengolahan Limbah Cair Pabrik Pupuk Urea Menggunakan Advanced Oxidation Processes

    Directory of Open Access Journals (Sweden)

    Darmadi Darmadi

    2014-06-01

    Full Text Available Limbah cair pabrik pupuk urea terdiri dari urea dan amonium yang masing-masing mempunyai konsentrasi berkisar antara 1500-10000 ppm dan 400-3000 ppm. Konsentrasi urea yang tinggi di dalam badan air dapat menyebabkan blooming algae dalam ekosistem tersebut yang dapat mengakibatkan kehidupan biota air lain terserang penyakit. Peristiwa ini terjadi karena kurangnya nutrisi bagi biota air dan sedikitnya sinar matahari yang dapat menembusi permukaan air. Disamping kedua hal tersebut di atas, algae juga dapat memproduksi senyawa beracun bagi biota air dan manusia. Penelitian ini bertujuan untuk mengolah urea menggunakan oksidasi konvensional (H2O2 dan Advanced Oxidation Processes (kombinasi H2O2-Fe2+ pada pH 5 dengan parameter yang digunakan adalah variasi konsen-trasi awal H2O2  dan konsentrasi Fe2+. Hasil percobaan menunjukkan bahwa penurunan konsentrasi urea tertinggi diperoleh pada penggunaan reagen fenton (8000 ppm H2O2 dan 500 ppm Fe2+, yaitu dapat menurunkan urea dari konsentrasi awal urea 2566,145 ppm menjadi 0 ppm. Kinetika reaksi dekomposisi urea menjadi amonium dan amonium menjadi nitrit dan nitrat yang diuji mengikuti laju kinetika reaksi orde 1 (satu terhadap urea dan orde satu terhadap amonium dengan konstanta laju reaksi masing-masing k1 = 0,019 dan k2 = 0,022 min-1.

  15. Alanine Counteracts the Destabilizing Effect that Urea has on RNase-A.

    Science.gov (United States)

    Chowhan, Rimpy K; Ali, Fasil; Bhat, Mohd Y; Rahman, Safikur; Singh, Laishram R; Ahmad, Faizan; Dar, Tanveer A

    2016-01-01

    It is generally believed that organisms use and accumulate methylamine osmolytes to prevent urea's damaging effect on protein stability and activity. However, urea-rich cells not only accumulate methylamines but also many other methylated and non-methylated compounds as well. But, so far it is not known whether osmolytes that are not accumulated in urea-rich cells could also confer urea-counteracting properties. We investigated the behavior of a non-methylamine osmolyte, alanine for its counteracting effect against urea denaturation of a model protein, ribonuclease A (RNase-A). We have measured structure and thermodynamic parameters (Tm, ΔHm, and ΔGD°) of RNase-A in the presence of alanine, urea and their combination. The results were also compared with the ability of glycine (osmolyte lacking one methyl group when compared with alanine) to counter urea's effect on protein stability. We observed that alanine but not glycine counteracts urea's harmful effect on RNase-A stability. The results indicated that alanine (in addition to methylamine osmolytes) may serve as an alternate urea-counteractant. Since glycine fails to protect RNase-A from urea's destabilizing effect, it seems that methylation to glycine might have some evolutionary significance to protect proteins against harmful effects of urea.

  16. Simultaneous measurement of neuronal and glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate

    Science.gov (United States)

    Deelchand, Dinesh K.; Nelson, Christopher; Shestov, Alexander A.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2009-02-01

    In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate was investigated. Time courses of 13C spectra were measured in vivo while infusing both 13C-labeled substrates simultaneously. Individual 13C isotopomers (singlets and multiplets observed in 13C spectra) were quantified automatically using LCModel. The distinct 13C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained with a temporal resolution of 11 min. Although dynamic metabolic modeling of these 13C isotopomer data will require further work and is not reported here, we expect that these new data will allow more precise determination of metabolic rates as is currently possible when using either glucose or acetate as the sole 13C-labeled substrate.

  17. Measurement of energy expenditure in overweight men and women using [C-14]-bicarbonate-urea before and after weight loss

    International Nuclear Information System (INIS)

    Luscombe, N.; Kirkwood, I.D.; Bellon, M.; Tsopelas, C.; Wittert, G.A.

    2002-01-01

    Full text: Many studies have demonstrated significant declines in 24-hour energy expenditure (TEE) measured by whole body calorimetry with either the process of weight loss or the maintenance of reduced body weight. The aims of this study were to determine the effect of weight loss and two weeks of weight maintenance on TEE using [ 14 C]-bicarbonate-urea, Eleven subjects (6 males, 5 females), mean (±SE) age 50 ± 3 years, BMI 34.1 ± 2.1 kg/m2 and body fat 38.7 ± 3% were studied before and after a decrease in body weight of > 8% over a period of 8 weeks, followed by two weeks of weight maintenance. Weight loss was induced using the combination of Modifast and one small meal a day (∼3.34 MJ/day). Body composition (DEXA), resting energy expenditure (REE) and the thermic effect of a 2.7 MJ test meal (TEF) were measured in addition to TEE at week 2 and again at week 12. Diet was assessed using diaries and physical activity energy expenditure (PAEE) was calculated from the equation: 0.9 x TEE-REE, which assumes that 10% of TEE is accounted for by the TEE. Body weight decreased by 11.8 ± 1.0% from week 2 to 10, and remained stable thereafter. Total fat mass, abdominal fat mass and lean mass decreased by 19.7 ± 1.8%, 21.8 ± 2.3% and 6.0 ± 1.1 % respectively. At week 12, REE decreased by 5.7 ± 1.3% (p < 0.002). The decreases in TEF (13.3 ± 13.7%), PAEE (31 ± 57.5%) and TEE (0.18 + 3.68%) were not significant. There was a significant relationship between the change in REE and overall body weight (p < 0.026) but not lean mass. It is concluded that in free-living subjects, after weight loss and two weeks of weight maintenance, REE but not TEE decreases, although there is substantial variability between individuals.Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  18. 76 FR 15339 - Solid Urea From Russia and Ukraine

    Science.gov (United States)

    2011-03-21

    ... Urea From Russia and Ukraine AGENCY: United States International Trade Commission. ACTION: Notice of... urea from Russia and Ukraine. SUMMARY: The Commission hereby gives notice that it will proceed with... determine whether revocation of the antidumping duty orders on solid urea from Russia and Ukraine would be...

  19. δ13C-CH4 in ice core samples

    DEFF Research Database (Denmark)

    Sperlich, Peter

    Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2) measure......Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2......) measurements of δ13C-CH4 in ice core samples as is required when δ13C-CH4 records that are measured in several laboratories are merged for analysis. Both the referencing and measurement techniques have been compared to further laboratories which proofed the accuracy of the analytical systems. The second part...

  20. Avaliação do Metabolismo Nutricional em Poedeiras pela Técnica dos Isótopos Estáveis do Ccarbono (13C/12C Nutritional Metabolism Evaluation of Laying Hens Using Stable-Carbon Isotopes (13C/12C

    Directory of Open Access Journals (Sweden)

    AS Carrijo

    2000-09-01

    Full Text Available Os isótopos estáveis do carbono que eram utilizados em estudos ecológicos e paleoecológicos apresentaram um incremento nos últimos trinta anos, na utilização em estudos dietéticos em animais. Entretanto, existem poucas informações sobre o padrão metabólico e sobre as taxas de turnover do 13C em aves. O presente experimento estabeleceu curvas de substituição e taxas de movimentação do 13C no ovo e no fígado de aves de postura adultas, pela substituição da ração comercial por dietas compostas de grãos dos ciclos fotossintéticos C3 e C4, durante 50 dias. A diferença no conteúdo isotópico do delta per mil do carbono-13 (delta‰ 13C entre as duas dietas foi de 16,13‰. A taxa de substituição do 13C das dietas, nos tecidos, adequou-se num modelo exponencial, descrevendo o turnover do carbono nos tecidos analisados. As taxas de movimentação do 13C, nas aves alimentadas com dieta baseada em grãos C3, foi maior no fígado em relação ao ovo, com valores para a meia-vida de 2,9 e 3,7 dias, respectivamente. As aves que receberam ração com grãos C4 apresentaram uma taxa de turnover no ovo superior àquela obtida para o fígado, com meia-vida de 4,0 e 5,3 dias, respectivamente. Os valores do delta‰13C observados para ovo e fígado diferiram em aproximadamente 2‰ daqueles referentes às dietas.The stable carbon isotopes used in ecology and paleoecology during the last 30 years has now been used in dietary studies of animals. However, there are not enough studies on the metabolism patterns and turnover rates of the 13C in avian. This experiment established the turnover rates of the 13C in egg and liver tissues of adult laying hens through the substitution of commercial diets by diets containing C3 and C4 photosynthetic cycle grains for 50 days. The delta‰13C difference in two diets contents was 16.13‰. The diets 13C turnover rates in tissues were adapted in an exponential model that describes the isotopic carbon

  1. 14C and 13C in the atmosphere and soil air at two localities of Slovakia

    International Nuclear Information System (INIS)

    Sivo, A.; Simon, J.; Richtarikova, M.; Holy, K.; Polaskova, A.; Bulko, M.; Hola, O.

    2006-01-01

    In this paper there are presented the long-term measurements of 13 R and 14 R in urban and countryside atmosphere. The different conditions and particularities of both the localities which influence on the mentioned characteristics are pointed out. The existence of δ 13 C and δ 14 C variations and their phase correlation were confirmed as well as their origin were qualitatively explained. By means of the non-linear regression and harmonic analysis the trends of δ 13 C and δ 14 C variations was found. The study of δ 13 C and δ 14 C courses has shown that it can be used as an effective tool to determine the level of the anthropogenic CO 2 pollution of the atmosphere. (authors)

  2. Experimental studies on urea degradation in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Rajendran, A.; Joseph, T.; Reddy, C.V.G.

    polluted waters, resulting in the accumulation of ammonia. The urea decomposing bacteria varied between 7 and 40% among the total heterotrophic bacteria in Velsao Bay, while these were from 15 to 22% near Mormugao. The rate for biological oxidation of urea...

  3. Pilas de combustible de una sola cámara, basadas en electrolitos de ceria dopada con gadolinia y operadas con metano y propano

    Directory of Open Access Journals (Sweden)

    Piñol, S.

    2010-02-01

    Full Text Available The main advantages of single-chamber solid oxide fuel cells (SOFCs respect to dual-chamber SOFCs, are to simplify the device design and to operate in mixtures of hydrocarbon (methane, propane… and air, with no separation between fuel and oxidant. However, this design requires the use of selective electrodes for the fuel oxidation and the oxidant reduction. In this work, electrolyte-supported SOFCs were fabricated using gadolinia doped ceria (GDC as the electrolyte, Ni + GDC as the anode and LSC(La0.5Sr0.5CoO3-δ-GDC-Ag2O as the cathode. The electrical properties of the cell were determined in mixtures of methane + air and propane + air. The influence of temperature, gas composition and total flow rate on the fuel cell performance was investigated. As a result, the power density was strongly increased with increasing temperature, total flow rate and hydrocarbon composition. Under optimized gas compositions and total flow conditions, power densities of 70 and 320 mW/cm2 operating on propane at a temperature of 600ºC and methane (795ºC were obtained, respectively.

    La principal ventaja de las pilas de combustible de óxido sólido (SOFCs de una sola cámara, frente a las bicamerales convencionales, es que permiten simplificar el diseño del dispositivo y operar con mezclas de hidrocarburos (metano, propano... y aire, sin necesidad de separar ambos gases, por medio del uso de electrodos selectivos a la oxidación del combustible y reducción del oxidante. En el presente trabajo, se han fabricado monopilas soportadas sobre electrolitos de ceria dopada con gadolinia (GDC, de 200 µm de espesor, usando Ni-GDC como ánodo y LSC(La0.5Sr0.5CoO3-δ-GDC-Ag2O como cátodo. Las propiedades eléctricas de la celda se determinaron en un reactor de una sola cámara, usando mezclas de metano + aire y propano + aire. Se investigó la influencia de la

  4. Calidad de vida relacionada con la salud, afrontamiento del estrés y emociones negativas en pacientes con cáncer en tratamiento quimioterapéutico

    OpenAIRE

    Ana Milena Gaviria; Stefano Vinaccia; María Fernanda Riveros; Japcy Margarita Quiceno

    2007-01-01

    El presente estudio tuvo como objetivo evaluar la calidad de vida relacionada con la salud, el afrontamiento del estrés y las emociones negativas en 28 pacientes de ambos géneros con diagnóstico de diferentes tipos de cáncer en tratamiento quimioterapéutico del Instituto de Medicancer de Medellín (Colombia). Se utilizaron los cuestionarios: EORTC QLQ-C30, que mide Calidad de Vida; el CAE, que evalúa Afrontamiento al Estrés, y la Escala de Ansiedad y Depresión Hospitalaria (H...

  5. The Relationship Between 14C Urea Breath Test Results and Neutrophil/Lymphocyte and Platelet/Lymphocyte Ratios

    Directory of Open Access Journals (Sweden)

    Ertan Şahin

    2018-04-01

    Full Text Available Aim: Neutrophil/lymphocyte ratio (NLR and platelet/lymphocyte ratio (PLR are used as inflammatory markers in several diseases. However, there are little data regarding the diagnostic ability of NLR and PLR in Helicobacter pylori. We aimed to assess the association between the 14C urea breath test (14C-UBT results and NLR and PLR in H. pylori diagnosis. Methods: Results of 89 patients were retrospectively analysed in this study. According to the 14C-UBT results, patients were divided into two groups: H. pylori (+ and H. pylori (- (control group. Haematological parameters, including hemoglobine, white blood cell (WBC count, neutrophil count, lymphocyte count, NLR, platelet count, and PLR were compared between the two groups. Results: The mean total WBC count, neutrophil count, NLR and PLR in H. pylori (+ patients were significantly higher than in the control group (p<0.001 for all these parameters. In the receiver operating characteristic curve analysis, the cut-off value for NLR and PLR for the presence of H. pylori was calculated as ≥2.39 [sensitivity: 67.3%, specificity: 79.4%, area under the curve (AUC: 0.747 (0.637-0.856, p<0.0001] and ≥133.3 [sensitivity: 61.8%, specificity: 55.9%, AUC: 0.572 (0.447-0.697, p<0.05], respectively. Conclusion: The present study shows that NLR and PLR are associated with H. pylori positivity based on 14C-UBT, and they can be used as an additional biomarker for supporting the 14C-UBT results.

  6. Utilization of 15N-labelled urea in laying hens. 7

    International Nuclear Information System (INIS)

    Gruhn, K.

    1987-01-01

    3 colostomized laying hybrids received 1% 15 N-labelled urea with 96.06 atom-% 15 N excess ( 15 N') with a commercial ration over a period of 6 days. After the application of the same ration with unlabelled urea on the following 2 days the animals were butchered. In the muscles of breast, legs and heart, the labelling of total nitrogen and the incorporation of urea 15 N' into 15 amino acids of the 3 different kinds of muscles were ascertained. On average, significant differences could be ascertained between the atom-% 15 N of the muscles was 0.25 and 0.34 atom-%, resp.; that of the cardial proteins 0.71 atom-% 15 N'. The incorporation of urea 15 N into the basic amino acids is low and varies both between the kinds of muscles and between the amino acids. On average the highest level of labelling was found among the essential amino acids valine, isoleucine and leucine; the average atom-% 15 N' for the muscles of the breast is 0.13, of the leg 0.17, and of the heart 0.27; the 15 N' quota of branched Chain amino acids in the total 15 N' of the respective muscle is accordingly 6.0%, 5.0% and 4.5%. The non-essential amino acids, particularly glutamic acid, are more highly labelled in the muscles than the essential ones. A 15 N' for glutamic acid of 0.24 atom-% in the breast muscles, of 0.27 atom-% in those of the legs and of 0.64 atom-% in the heart muscle could be detected. The average quota of the 15 N' of these acid amino acids in the 15 N' for breast, leg and heart muscles is 7.4, 6.2 and 6.7, resp. The quota of the 15 N' in the 6 non-essential amino acids in the total 15 N' in all 3 kinds of muscles is approximately two thirds and in the 9 essential ones one third of the total 15 N'. Although the results show that there is a certain incorporation of 15 N' from urea into the amino acids of the muscle proteins, their contribution to meeting the demands is irrelevant. (author)

  7. Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

    Science.gov (United States)

    Chung-Yun Hse

    2009-01-01

    To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

  8. Analysis Ratio of Uranyl/Urea and Uranyl/HMTA on the ComplexesUranyl-Urea and Uranyl-HMTA with Spectrophotometry Method

    International Nuclear Information System (INIS)

    Simbolon, Sahat

    2000-01-01

    Reaction between uranyl and urea and uranyl and HMTA was investigated atpH = 4 and room temperature. The result of the reaction was measured withspectrophotometer, each absorbance was pictured between mol fraction andabsorbance for uranyl - urea and uranyl - HMTA. The linear and horizontalcurve was found for reaction uranyl - urea, meanwhile S curve for thereaction uranyl and HMTA. It was found that reaction between uranyl and HMTAon mol fraction value less than 0.25 was complexes meanwhile on the range of0.25 and 0.5 the reaction between uranyl and HMTA was stoichiometries.(author)

  9. Nanohybrid-layered double hydroxides/urease materials: Synthesis and application to urea biosensors

    International Nuclear Information System (INIS)

    Vial, S.; Forano, C.; Shan, D.; Mousty, C.; Barhoumi, H.; Martelet, C.; Jaffrezic, N.

    2006-01-01

    Nanohybrid [ZnAl]-layered double hydroxides/urease were prepared for the first time using the coprecipitation of enzyme and inorganic matrix. By varying the respective amount of urease and LDH, we obtained hybrid materials with various amount and dispersion rate of active biomolecules. X-ray diffraction and infrared spectroscopy confirm the preservation of the structure of each partner while the morphology properties are in good agreement with the permeability study. These new nanohybrids were applied for the development of urea biosensors. Biosensor responses to urea additions were obtained using capacitance (C vs. V) measurements at urease-LDH biofilm deposited on an insulated semiconductor (IS) structure

  10. Síndrome de lisis tumoral en un paciente con cáncer de riñón tratado con sunitinib

    Directory of Open Access Journals (Sweden)

    Ezequiel Rodríguez-Reimúndes

    2011-04-01

    Full Text Available El síndrome de lisis tumoral (SLT es un trastorno metabólico que ocurre como consecuencia de una destrucción celular masiva. Se caracteriza por la presencia de hiperuricemia, hiperfosfatemia, hipocalcemia e hiperkalemia, y predispone al desarrollo de insuficiencia renal aguda. En la mayoría de los casos el SLT ocurre luego de instaurarse un tratamiento antitumoral y es más frecuente en tumores de alto grado de malignidad y alta sensibilidad a la quimioterapia. Presentamos el caso de un paciente con diagnóstico de cáncer de riñón recidivado que presenta un SLT e insuficiencia renal aguda luego de iniciar tratamiento con sunitinib.

  11. Volumetric spiral chemical shift imaging of hyperpolarized [2-(13) c]pyruvate in a rat c6 glioma model.

    Science.gov (United States)

    Park, Jae Mo; Josan, Sonal; Jang, Taichang; Merchant, Milton; Watkins, Ron; Hurd, Ralph E; Recht, Lawrence D; Mayer, Dirk; Spielman, Daniel M

    2016-03-01

    MRS of hyperpolarized [2-(13)C]pyruvate can be used to assess multiple metabolic pathways within mitochondria as the (13)C label is not lost with the conversion of pyruvate to acetyl-CoA. This study presents the first MR spectroscopic imaging of hyperpolarized [2-(13)C]pyruvate in glioma-bearing brain. Spiral chemical shift imaging with spectrally undersampling scheme (1042 Hz) and a hard-pulse excitation was exploited to simultaneously image [2-(13)C]pyruvate, [2-(13)C]lactate, and [5-(13)C]glutamate, the metabolites known to be produced in brain after an injection of hyperpolarized [2-(13)C]pyruvate, without chemical shift displacement artifacts. A separate undersampling scheme (890 Hz) was also used to image [1-(13)C]acetyl-carnitine. Healthy and C6 glioma-implanted rat brains were imaged at baseline and after dichloroacetate administration, a drug that modulates pyruvate dehydrogenase kinase activity. The baseline metabolite maps showed higher lactate and lower glutamate in tumor as compared to normal-appearing brain. Dichloroacetate led to an increase in glutamate in both tumor and normal-appearing brain. Dichloroacetate-induced %-decrease of lactate/glutamate was comparable to the lactate/bicarbonate decrease from hyperpolarized [1-(13)C]pyruvate studies. Acetyl-carnitine was observed in the muscle/fat tissue surrounding the brain. Robust volumetric imaging with hyperpolarized [2-(13)C]pyruvate and downstream products was performed in glioma-bearing rat brains, demonstrating changes in mitochondrial metabolism with dichloroacetate. © 2015 Wiley Periodicals, Inc.

  12. In vivo 13C MRS in the mouse brain at 14.1 Tesla and metabolic flux quantification under infusion of [1,6-13C2]glucose.

    Science.gov (United States)

    Lai, Marta; Lanz, Bernard; Poitry-Yamate, Carole; Romero, Jackeline F; Berset, Corina M; Cudalbu, Cristina; Gruetter, Rolf

    2017-01-01

    In vivo 13 C magnetic resonance spectroscopy (MRS) enables the investigation of cerebral metabolic compartmentation while, e.g. infusing 13 C-labeled glucose. Metabolic flux analysis of 13 C turnover previously yielded quantitative information of glutamate and glutamine metabolism in humans and rats, while the application to in vivo mouse brain remains exceedingly challenging. In the present study, 13 C direct detection at 14.1 T provided highly resolved in vivo spectra of the mouse brain while infusing [1,6- 13 C 2 ]glucose for up to 5 h. 13 C incorporation to glutamate and glutamine C4, C3, and C2 and aspartate C3 were detected dynamically and fitted to a two-compartment model: flux estimation of neuron-glial metabolism included tricarboxylic acid cycle (TCA) flux in astrocytes (V g  = 0.16 ± 0.03 µmol/g/min) and neurons (V TCA n  = 0.56 ± 0.03 µmol/g/min), pyruvate carboxylase activity (V PC  = 0.041 ± 0.003 µmol/g/min) and neurotransmission rate (V NT  = 0.084 ± 0.008 µmol/g/min), resulting in a cerebral metabolic rate of glucose (CMR glc ) of 0.38 ± 0.02 µmol/g/min, in excellent agreement with that determined with concomitant 18 F-fluorodeoxyglucose positron emission tomography ( 18 FDG PET).We conclude that modeling of neuron-glial metabolism in vivo is accessible in the mouse brain from 13 C direct detection with an unprecedented spatial resolution under [1,6- 13 C 2 ]glucose infusion.

  13. Validation of a simplified carbon-14-urea breath test for routine use for detecting Helicobacter pylori noninvasively

    International Nuclear Information System (INIS)

    Henze, E.; Malfertheiner, P.; Clausen, M.; Burkhardt, H.; Adam, W.E.

    1990-01-01

    A carbon-14 ( 14 C) urea breath test for detecting Helicobacter pylori with multiple breath sampling was developed. Carbon-14-urea (110 kBq) administered orally to 18 normal subjects and to 82 patients with Helicobacter infection. The exhaled 14 C-labeled CO 2 was trapped at 10-min intervals for 90 min. The total 14 C activity exhaled over 90 min was integrated and expressed in %activity of the total dose given. In normals, a mean of 0.59% +/- 0.24% was measured, resulting in an upper limit of normal of 1.07%. In 82 patients, a sensitivity of 90.2%, a specificity of 83.8%, and a positive predictive value of 90.2% was found. The single probes at intervals of 40-60 min correlated best with the integrated result, with r ranging from 0.986 to 0.990. The test's diagnostic accuracy did not change at all when reevaluated with the 40-, 50-, or 60-min sample data alone. Thus, the 14 C-urea breath test can be applied routinely as a noninvasive, low-cost and one-sample test with high diagnostic accuracy in detecting Helicobacter pylori colonization

  14. DIAGNOSTIC ACCURACY OF UREA BREATH TEST FOR HELICOBACTER PYLORI INFECTION IN CHILDREN WITH DYSPEPSIA IN COMPARISON TO HISTOPATHOLOGY

    Directory of Open Access Journals (Sweden)

    Naser HONAR

    Full Text Available ABSTRACT Background - Helicobacter pylori infection is the gram negative bacillus with the close association with chronic antral gastritis. Objective - In this study, we evaluate the accuracy of urea breath test (UBT with carbon isotope 13 in comparison with histopathology of gastric antrum for detection of H. pylori infection in children with dyspepsia. Methods - This cross-sectional study was performed at specialized laboratory of Shiraz Gastroenterohepatology Research Center and Nemazee Hospital, Iran, during a 12-months period. This study investigated the sensitivity, specificity, and positive and negative predictive values of UBT in comparison with biopsy-based tests. We included a consecutive selection of 60 children who fulfilled Rome III criteria for dyspepsia. All children were referred for performing UBT with carbon isotope 13 (C13 as well as endoscopy. Biopsies were taken from antrum of stomach and duodenum. The pathologic diagnosis was considered as the standard test. Results - The mean age of the participants was 10.1±2.6 (range 7-17 years. From our total 60 patients, 28 (46.7% had positive UBT results and 32 (53.3% had negative UBT results. Pathologic report of 16 (57.1% out of 28 patients who had positive UBT were positive for H. pylori and 12 (42.9% ones were negative. Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Conclusion - Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Another multicenter study from our country is recommended.

  15. Assessment of Health Effects of Exogenous Urea: Summary and Key Findings.

    Science.gov (United States)

    Dickerson, Aisha S; Lee, Janice S; Keshava, Channa; Hotchkiss, Andrew; Persad, Amanda S

    2018-05-01

    Urea has been utilized as a reductant in diesel fuels to lower emission of nitrogen oxides, igniting interest in probable human health hazards associated with exposure to exogenous urea. Here, we summarize and update key findings on potential health effects of exogenous urea, including carcinogenicity. No definitive target organs for oral exposure were identified; however, results in animal studies suggest that the liver and kidney could be potential target organs of urea toxicity. The available human-subject literature suggests that the impact on lung function is minimal. Based on the literature on exogenous urea, we concluded that there was inadequate information to assess the carcinogenic potential of urea, or perform a quantitative assessment to derive reference values. Given the limited information on exogenous urea, additional research to address gaps for exogenous urea should include long-term cancer bioassays, two-generation reproductive toxicity studies, and mode-of-action investigations.

  16. Diminished renal urea excretion in the llama at reduced food intake

    International Nuclear Information System (INIS)

    Engelhardt, W.; Engelhardt, W. von

    1976-01-01

    Renal urea excretion was studied in three llamas under various feeding conditions. Glomerular filtration rate (GFR) was estimated from inulin clearance. Tubular reabsorbed urea was the difference between glomerular filtered and renal excreted urea. Plasma urea concentration increased significantly when feeding was reduced by 40% and 60%, not applicable to a straw diet. With reduced hay feeding and on a straw diet only a slight and insignificant decrease was observed in renal urea excretion, with only a 3% lowering in GFR and glomerular filtered urea. With a straw diet, the glomerular filtered urea was significantly below the controls. The fraction of filtered urea reabsorbed in the tubules was constant (36%-47%). Very high reabsorption (87%) on a supplemented straw dietwas observed in one llama which after nearly 6 months on this low protein diet - could be shown to have lost only 5% of its body weight

  17. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of {sup 111}In-DTPA-D-Phe{sup 1}-octreotide, {sup 99m}Tc-MIBI, {sup 14}C-triolein and {sup 14}C-urea, and development of dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Leide Svegborn, S

    1999-03-01

    Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with {sup 111}In-DTPA-D-Phe{sup 1}-octreotide (for diagnosis of neuroendocrine tumours) and {sup 99m}Tc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. {sup 111}In-DTPA-D-Phe{sup 1}-octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). {sup 99m}Tc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of {sup 14}CO{sub 2}, in exhaled air from patients undergoing {sup 14}C-breath tests, with special application to {sup 14}C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of {sup 14}C, and was used together with liquid scintillation counting in an investigation of the biokinetics of {sup 14}C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for {sup 14}C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children

  18. Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi).

    Science.gov (United States)

    Giacomin, Marina; Schulte, Patricia M; Wood, Chris M

    Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi. We hypothesized that as metabolic demand for oxygen increased with temperature, the fluxes of ammonia, urea-N, and 3 H 2 O at the gills would increase in parallel with those of oxygen. Oxygen consumption (overall [Formula: see text] from 7.5° to 22°C) and water fluxes (overall [Formula: see text]) responded to increases in temperature in a similar, almost linear, manner. Ammonia-N efflux rates varied the most, increasing almost 15-fold from 7.5° to 22°C ([Formula: see text]). Urea-N efflux was tightly conserved over the 7.5°-15°C range ([Formula: see text]) but increased greatly at higher temperatures, yielding an overall [Formula: see text]. These differences likely reflect differences in the transport pathways for the four moieties. They also suggest the failure of urea-N- and ammonia-N-conserving mechanisms at the gill above 15°C. Hyperoxia did not alleviate the effects of high temperature. Indeed, urea-N and ammonia-N effluxes were dramatically increased when animals were exposed to high temperatures in the presence of hyperoxia, suggesting that high partial pressure of oxygen may have caused oxidative damage to gill epithelial membranes.

  19. Quantitative importance of the pentose phosphate pathway determined by incorporation of 13C from [2-13C]- and [3-13C]glucose into TCA cycle intermediates and neurotransmitter amino acids in functionally intact neurons.

    Science.gov (United States)

    Brekke, Eva M F; Walls, Anne B; Schousboe, Arne; Waagepetersen, Helle S; Sonnewald, Ursula

    2012-09-01

    The brain is highly susceptible to oxidative injury, and the pentose phosphate pathway (PPP) has been shown to be affected by pathological conditions, such as Alzheimer's disease and traumatic brain injury. While this pathway has been investigated in the intact brain and in astrocytes, little is known about the PPP in neurons. The activity of the PPP was quantified in cultured cerebral cortical and cerebellar neurons after incubation in the presence of [2-(13)C]glucose or [3-(13)C]glucose. The activity of the PPP was several fold lower than glycolysis in both types of neurons. While metabolism of (13)C-labeled glucose via the PPP does not appear to contribute to the production of releasable lactate, it contributes to labeling of tricarboxylic acid (TCA) cycle intermediates and related amino acids. Based on glutamate isotopomers, it was calculated that PPP activity accounts for ~6% of glucose metabolism in cortical neurons and ~4% in cerebellar neurons. This is the first demonstration that pyruvate generated from glucose via the PPP contributes to the synthesis of acetyl CoA for oxidation in the TCA cycle. Moreover, the fact that (13)C labeling from glucose is incorporated into glutamate proves that both the oxidative and the nonoxidative stages of the PPP are active in neurons.

  20. Transgenic Restoration of Urea Transporter A1 Confers Maximal Urinary Concentration in the Absence of Urea Transporter A3.

    Science.gov (United States)

    Klein, Janet D; Wang, Yanhua; Mistry, Abinash; LaRocque, Lauren M; Molina, Patrick A; Rogers, Richard T; Blount, Mitsi A; Sands, Jeff M

    2016-05-01

    Urea has a critical role in urinary concentration. Mice lacking the inner medullary collecting duct (IMCD) urea transporter A1 (UT-A1) and urea transporter A3 (UT-A3) have very low levels of urea permeability and are unable to concentrate urine. To investigate the role of UT-A1 in the concentration of urine, we transgenically expressed UT-A1 in knockout mice lacking UT-A1 and UT-A3 using a construct with a UT-A1 gene that cannot be spliced to produce UT-A3. This construct was inserted behind the original UT-A promoter to yield a mouse expressing only UT-A1 (UT-A1(+/+)/UT-A3(-/-)). Western blot analysis demonstrated UT-A1 in the inner medulla of UT-A1(+/+)/UT-A3(-/-) and wild-type mice, but not in UT-A1/UT-A3 knockout mice, and an absence of UT-A3 in UT-A1(+/+)/UT-A3(-/-) and UT-A1/UT-A3 knockout mice. Immunohistochemistry in UT-A1(+/+)/UT-A3(-/-) mice also showed negative UT-A3 staining in kidney and other tissues and positive UT-A1 staining only in the IMCD. Urea permeability in isolated perfused IMCDs showed basal permeability in the UT-A1(+/+)/UT-A3(-/-) mice was similar to levels in wild-type mice, but vasopressin stimulation of urea permeability in wild-type mice was significantly greater (100% increase) than in UT-A1(+/+)/UT-A3(-/-) mice (8% increase). Notably, basal urine osmolalities in both wild-type and UT-A1(+/+)/UT-A3(-/-) mice increased upon overnight water restriction. We conclude that transgenic expression of UT-A1 restores basal urea permeability to the level in wild-type mice but does not restore vasopressin-stimulated levels of urea permeability. This information suggests that transgenic expression of UT-A1 alone in mice lacking UT-A1 and UT-A3 is sufficient to restore urine-concentrating ability. Copyright © 2016 by the American Society of Nephrology.