Topic
Urea
About: Urea is a research topic. Over the lifetime, 21394 publications have been published within this topic receiving 382444 citations. The topic is also known as: carbamide & carbonic acid diamide.
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TL;DR: In this paper, the thermal decomposition of urea was studied under flow reactor conditions using a differential scanning calorimeter (DSC) and Fourier transformed infrared spectroscopy (FT-IR).
136 citations
TL;DR: The hypothesis that muscle protein breakdown and amino acid catabolism are increased by exercise is supported and previous reports of increased protein degradation in the perfused hindquarter and increased levels of essential amino acids in muscle, liver, and plasma of exercised rats are supported.
Abstract: This study was undertaken to investigate whether an exercise bout increases muscle protein degradation and amino acid catabolism. The excretion of urea and N tau -methylhistidine before and after a...
135 citations
TL;DR: The metabolic range of acid-adapted H. pylori is between an environmental pH of 3.5 and 8.6 and is an acid-tolerant neutralophile due to internal urease activity, which allows metabolism in the pH range between 4.0 and 2.0.
135 citations
TL;DR: An autoclave method based on the oxidation of dissolved organic matter with alkaline persulphate for the analysis of total soluble nitrogen (N) and phosphorus (P) in 0.01M calcium chloride (CaCl2), 0.5M potassium sulfate (K2SO4), or 0.2M sulfuric acid (H 2SO4) extracts of fresh and fumigated soils is described in this paper.
Abstract: An autoclave method based on the oxidation of dissolved organic matter with alkaline persulphate for the analysis of total soluble nitrogen (N) and phosphorus (P) in 0.01M calcium chloride (CaCl2), 0.5M potassium sulfate (K2SO4), or 0.2M sulfuric acid (H2SO4) extracts of fresh and fumigated soils is described. Autoclaving at 110°C for 30 min oxidized N at 50 mg N/dm3 from urea, glucosamine, and the sodium salt of ethylenediaminetetra‐acetic acid (EDTA) to nitrate (NO3). Recoveries decreased with increasing concentrations of total organic carbon (TOC), hence glucosamine and EDTA required an increased concentration of persulphate. Tests with added glucose showed that recovery of urea N was complete up to a carbon (C) concentration of 100 mg/dm3. For P, it was important that solutions of 0.01M CaCl2 were acidic after oxidation to avoid the precipitation of appatite. Recoveries of P from orthphosphate and inositol hexaphosphate dodeca sodium salt in water or in 0.2M H2SO4 were complete after oxidatio...
135 citations
TL;DR: The use of Raman spectroscopy to analyze components in human urine is examined to find out if it can be used to detect cancerous deposits in the blood.
Abstract: Background and Objective: We examine the use of Raman spectroscopy to analyze components in human urine. Study Design/Methods and Meterials: Targeted urine components include urea, uric acid, and creatinine. Results: Urea concentration in urine is sufficiently high that normal Raman spectroscopy may be used for its analysis. All other components are in low concentrations requiring the use of surface-enhanced Raman spectroscopic methods (SERS). Conclusion: Both normal Raman and SERS approaches have been investigated for total urine-nitrogen determination, urine urea-nitrogen determination, and for the urea/ creatinine excretion ratio.
135 citations