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1.
Chemosphere ; 265: 129052, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33246703

RESUMO

The urea oxidation reaction (UOR) and nitrophenol reduction are safe and key limiting reactions for sustainable energy conversion and storage. Urea and nitrophenol are abundant in industrial and agricultural wastes, human wastewater, and in the environment. Catalytic oxidative and reductive removal is the most effective process to remove urea and 4-nitrophenol from the environment, necessary to protect human health. 2D carbon-supported, cobalt nanoparticle-based materials are emerging catalysts for nitrophenol reduction and as an anode material for the UOR. In this work, cobalt modified on a porous organic polymer (CoPOP) was synthesized and carbonized at 400 and 600 °C. The formation of CoPOP was confirmed by FT-IR spectroscopy, the 2D graphitic layer and amorphous carbon with cobalt metal by TEM, SEM, and PXRD, and the elemental composition by TEM mapping, EDX, and XPS. The catalytic activity for the 4-nitrophenol reduction was studied and the related electrocatalytic UOR was scientifically evaluated. The catalytic activity toward the reduction of 4-NP to 4-AP was tested with the addition of NaBH4; CoPOP-3 exhibited enhanced activity at a rate of 0.069 min-1. Furthermore, LSV investigated the catalytic activity of materials toward UOR, producing hydrogen gas, the products of which were analyzed via gas chromatography. Among the electrocatalysts studied, CoPOP-2 exhibited a lower onset potential, and the Tafel slope was 1.34 V and 80 mV dec-1. This study demonstrates that cobalt metal-doped porous organic polymers can be used as efficient catalysts to remove urea and nitrophenol from wastewater.


Assuntos
Cobalto , Polímeros , Humanos , Nitrofenóis , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ureia
2.
Sci Total Environ ; 757: 143751, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33250259

RESUMO

Low contents of water-soluble carbohydrates and/or low indigenous microbial activity in wilted maize stover (WMS) usually hinder the establishment of the ensiling process, thereby resulting in a low biogas production because of high loss of dry matter (DM). To enhance the biological activity and substrate biodegradability, this study applied the synergistic regulation of sucrose (carbon source) and increasing levels of urea (nitrogen source) during the ensiling process of WMS. Compared with the application of only sucrose, a higher organic acid content (lactic acid (85 g/kg-DM) and acetic acid (14 g/kg-DM)) and higher degradation ratios for lignocellulose (hemicellulose (28%), cellulose (22%), and lignin (17%)) were observed with urea applications of 1.7% (DM) and 3.9% (DM), respectively. This was caused by the enhanced activities of the hetero-fermenter (Weissella) and cellulolytic bacteria (Cellulosimicrobium). A simultaneous addition of urea and sucrose during the ensiling of WMS increased the specific methane yield by 11.2%-21.1% in comparison to raw WMS. Moreover, an economic cost estimation revealed that this approach could be an effective storage strategy for the efficient production of methane when employing a 1.7% (DM) urea application.


Assuntos
Ureia , Zea mays , Biocombustíveis , Fermentação , Metano , Silagem/análise
3.
Physiol Plant ; 171(1): 137-150, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32997341

RESUMO

Many plants grown with low-millimolar concentration of NH4 + as a sole nitrogen source develop NH4 + -toxicity symptoms. To date, crucial molecular identities and a practical approach involved in the improvement of plant NH4 + -tolerance remain largely unknown. By phenotyping of upland cotton grown on varied nitrogen forms, we came across a phenomenon that caused sub-millimolar concentrations of urea (e.g., up 50 µM) to repress the growth inhibition of roots and whole plant cultivated in a NH4 + -containing nutrient solution. A growth-recovery assay revealed that the relief in NH4 + -inhibited growth required only a short-term exposure (≧12 h) of the roots to urea, implying that urea could elicit an internal signaling and be involved in antagonizing NH4 + -sensitivity. Intriguingly, split-root experiments demonstrated that low urea occurrence in one root-half could efficaciously stimulate not only supplied root but also the root-half grown in NH4 + -solution without urea, indicating the existence of urea-triggered local and systemic long-distance signaling. In the split-root experiment we also observed high arginase activity, strong arginine reduction and remarkable upregulation of polyamine biosynthesis-related genes (ADC1/2, SPDS and SPMS). Therefore, we suggest that external urea might serve as an effective cue (signal molecule) in an arginine-/polyamine-related process for ameliorating NH4 + -suppressed root growth, providing a novel aspect for deeper exploring and understanding plant NH4 + -tolerance.


Assuntos
Compostos de Amônio , Sinais (Psicologia) , Gossypium , Nitrogênio , Raízes de Plantas , Ureia/farmacologia
4.
Sci Total Environ ; 755(Pt 2): 142580, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33059137

RESUMO

The discovery of complete ammonia oxidizer (comammox) was a breakthrough in the study of nitrification. However, slow growth of comammox bacteria makes it challenging to distinguish them from traditional ammonia oxidizing microorganisms. Genomic data indicated that comammox bacteria encoded genes that can metabolize urea and had higher nitrite tolerance, which could only be found in several ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). This implies that using nitrite and urea as nitrogen sources may accelerate comammox bacteria's enrichment efficiency. In this study, two reactors using nitrite and urea as substrates, respectively, were operated for 390 days. At the end of cultivation, the reactor fed with urea exhibited higher nitrification potential than the reactor fed with nitrite. Comammox bacteria outcompeted AOA and AOB, regardless of whether they were cultured with nitrite or urea. Using nitrite can improve the proportion of comammox amoA to total amoA of 92%, while using urea may increase the proportion of comammox bacteria among total bacteria to 14.2%. Metagenomic results implied that nitrite was converted to ammonia by nitrate reduction and absorbed by comammox bacteria. On the other hand, urea may be directly utilized as substrate. These results demonstrated that using different nitrogen sources caused niche differentiation of comammox bacteria, AOA, and AOB. Using nitrite can increase the relative abundance of comammox amoA to total amoA, while using urea can increase the quantity of comammox amoA. Comammox bacteria were dominant among ammonia oxidizing microorganisms for both nitrite and urea cultures.


Assuntos
Nitritos , Ureia , Amônia , Archaea/genética , Bactérias/genética , Nitrificação , Oxirredução , Filogenia , Microbiologia do Solo
5.
Sci Total Environ ; 755(Pt 2): 143198, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33162136

RESUMO

Urine and fecal excretions from cattle contribute to global nitrogen (N) emissions. The milk urea nitrogen (MUN) concentration in dairy cows is positively correlated with urinary urea N (UUN) emissions, and both decline with the reduction in crude protein intake. However, MUN concentration may differ between individual cows despite feeding the same ration. Thus, we hypothesized that due to differences in endogenous N utilization cows with high MUN concentration excrete more UUN than cows with a low MUN concentration. The objective of the present study was to elucidate N partitioning and urea metabolism in dairy cows with divergent MUN concentrations fed two planes of crude protein. Twenty Holstein dairy cows with high (HMU; n = 10) and low (LMU; n = 10) milk urea concentrations were fed two isocaloric diets with a low (LP) and normal (NP) crude protein level. Methane and ammonia emissions were recorded in respiration chambers. Feed intake, feces and urine excretions and milk yield were recorded for four days and subsamples were analyzed for total N and N-metabolites. A carbon-13 labeled urea bolus was administered intravenously followed by a series of plasma samplings. Total N and UUN excretions and ammonia emissions from excreta were lower on the LP diet, however, methane emissions, urinary N excretions and ammonia emissions were comparable between groups. Although plasma and salivary urea concentrations, urea pool size and urea turnover were higher, HMU cows had lower renal urea clearance rates. Additionally, HMU cows had lower renal clearance rates for creatinine, uric acid and creatine and excreted less uric acid (on the LP diet only) and creatine with urine. In conclusion, contrary to our hypothesis, HMU cows did not excrete more UUN than LMU cows. The lower urinary creatine excretion of HMU cows suggests that these animals have a lower environmental nitrogen footprint.


Assuntos
Leite , Ureia , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Feminino , Lactação , Leite/química , Nitrogênio/análise , Rúmen , Ureia/análise
6.
Chemosphere ; 263: 127913, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32822931

RESUMO

In addition to nitrogen, carbonyl compounds such as formaldehyde, acetaldehyde, isobutyraldehyde and crotonaldehyde can be released from slow release fertilizers based on urea-aldehyde by hydrolytic or biotic processes. A possible relevance of such releases in the practical application of corresponding products was investigated in laboratory experiments. In the first part, emissions of organic compounds from the pure products were determined in desiccators under static conditions in dry and water-saturated air as well as during direct contact with water. Significant emissions of isobutyraldehyde were found for products containing isobutylidene diurea. Several formulations emitted acetaldehyde and formaldehyde, especially in the case of higher air humidity and when solved in water. However, crotonaldehyde was not detected in the desiccator air. Other organic components such as herbicides or their degradation products and nitrification inhibitors were released from fertilizers containing these compounds. In further experiments, sticks and granules were applied into potting soil and the release of organic compounds in emission chambers was examined under dynamic conditions. No substances that could be directly attributed to the fertilizers were detected in these experiments. However, relevant emission rates of formaldehyde were observed for the spray fertilizers containing urea-formaldehyde after application to tomato plants. The possible contribution of these emissions to atmospheric formaldehyde concentrations is discussed. Finally, the formaldehyde concentrations in a greenhouse for private use are estimated. It is likely that immediately after spray application of a urea-formaldehyde fertilizer increased formaldehyde concentrations in the breathing air of the greenhouse occur.


Assuntos
Fertilizantes/análise , Formaldeído/análise , Nitrogênio/análise , Acetaldeído , Agricultura , Aldeídos , Óxido Nitroso/análise , Solo , Ureia
7.
Food Chem ; 339: 127844, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829243

RESUMO

Fat-filled milk powders (FMP) are inexpensive milk alternatives predominantly exported to developing countries to satisfy growing demands for dairy proteins. Harsh climatic and sanitary conditions, poor border controls and relatively long periods for distribution and storage enhance the inherent vulnerability of FMP to fraud and stability. Rapid, low-cost methods are needed for extensive routine authentication of FMP products. This study investigated, for the first time, the sample integrity and the quality dynamics of 7 Nigerian FMP brands stored for 7 weeks at 40 °C. The prominent melamine and urea absorption peaks were absent, but protein contents were below the permitted limit. The peak absorbance of the OH functional group increased while the tryptophan contents decreased with storage time. Multiclass analyses differentiated the fresh FMP brands from one another, and from those that were aged. Robust interval-PLS predictions obtained for storage time may be excellent indicators of FMP freshness and stability.


Assuntos
Embalagem de Alimentos/métodos , Leite/química , Animais , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Ácidos Graxos/análise , Microbiologia de Alimentos , Análise dos Mínimos Quadrados , Leite/microbiologia , Nigéria , Pós/química , Análise de Componente Principal , Salmonella/isolamento & purificação , Temperatura , Triazinas/análise , Ureia/análise
8.
Sci Total Environ ; 749: 142213, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33370919

RESUMO

Source-separated urine is an attractive fertilizer due to its high nutrient content, but the rapidly hydrolysis of urea leads to ammonia volatilization and other environmental problems. Urine stabilization, which meanly means preventing enzymatic urea hydrolysis, receives increasing attention. Accordingly, this study developed a technique to stabilize fresh urine by heat-activated peroxydisulfate (PDS). The effect of three crucial parameters, including temperature (55, 62.5, and 70 °C), heat-activated time (1, 2, and 3 h), and PDS concentration (10, 30, and 50 mM) that affect the activation of PDS in urine stabilization were investigated. Nitrogen in fresh urine treated with 50 mM PDS at 62.5 °C for 3 h existed mainly in the form of urea for more than 22 days at 25 °C. Moreover, the stabilized urine could remain stable and resist second contamination by continuous and slow pH decrease due to PDS decomposition during storage. Less than 8% of nitrogen loss in stabilized urine was detected during the experiment. The investigation of nitrogen transformation pathway demonstrated that urea was decomposed into NH4+ by heat-activated PDS and further oxidized to NO2- and NO3-. The nitrogen loss during treatment occurred via heat-driven ammonia volatilization and N2 emission produced by synproportionation of NO2- and NH4+ under acid and thermal conditions. Overall, this study investigated an efficient approach of urine stabilization to improve urine utilization in terms of nutrient recovery.


Assuntos
Temperatura Alta , Nitrogênio , Amônia , Fertilizantes/análise , Ureia , Urina/química
9.
Nat Metab ; 2(12): 1459-1471, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33288952

RESUMO

Hibernation is a state of extraordinary metabolic plasticity. The pathways of amino acid metabolism as they relate to nitrogen homeostasis in hibernating mammals in vivo are unknown. Here we show, using pulse isotopic tracing, evidence of increased myofibrillar (skeletal muscle) protein breakdown and suppressed whole-body production of metabolites in vivo throughout deep torpor. As whole-body production of metabolites is suppressed, amino acids with nitrogenous side chains accumulate during torpor, while urea cycle intermediates do not. Using 15N stable isotope methodology in arctic ground squirrels (Urocitellus parryii), we provide evidence that free nitrogen is buffered and recycled into essential amino acids, non-essential amino acids and the gamma-glutamyl system during the inter-bout arousal period of hibernation. In the absence of nutrient intake or physical activity, our data illustrate the orchestration of metabolic pathways that sustain the provision of essential and non-essential amino acids and prevent ammonia toxicity during hibernation.


Assuntos
Amônia/toxicidade , Hibernação/fisiologia , Músculo Esquelético/fisiologia , Nitrogênio/metabolismo , Sciuridae/fisiologia , Aminoácidos/metabolismo , Animais , Regiões Árticas , Nível de Alerta , Rim/metabolismo , Miofibrilas/metabolismo , Torpor/fisiologia , Ureia/metabolismo , gama-Glutamil Hidrolase/metabolismo
10.
Environ Pollut ; 267: 114142, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33254625

RESUMO

The emergence of organophosphorus flame retardants and the efficient removal from aquatic environments have aroused increasing concerns. The Urea functionalized Fe3O4@LDH (Urea-Fe3O4@LDH) was prepared and used to adsorb triphenyl phosphate (tphp) for the first time. The tphp adsorption capacity was up to 589 mg g-1, and the adsorption rate reached 49.9 mg g-1 min-1. Moreover, the influences of various environmental factors (pH, ionic strength and organic matter) on the tphp adsorption on the Urea-Fe3O4@LDH were investigated. The initial pH of the solution significantly affected the tphp adsorption, whereas the ionic strength and HA slightly affected the adsorption. The main adsorption mechanism was attributed to electrostatic interaction and π-π interaction. We believe that urea is one of excellent functional groups for the tphp adsorption removal and the materials with urea groups as the adsorbents exhibit good prospects in the future.


Assuntos
Retardadores de Chama , Ureia , Adsorção , Organofosfatos
11.
PLoS One ; 15(11): e0242254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33196667

RESUMO

BACKGROUND: Residual kidney function (RKF) is associated with improved survival and quality of life in dialysis patients. Previous studies have suggested that initiation of peritoneal dialysis (PD) may slow RKF decline compared to the pre-dialysis period. We sought to evaluate the association between PD initiation and RKF decline in the Initiating Dialysis Early And Late (IDEAL) trial. METHODS: In this post hoc analysis of the IDEAL randomized controlled trial, PD participants were included if results from 24-hour urine collections had been recorded within 30 days of dialysis initiation, and at least one value pre- and one value post-dialysis commencement were available. The primary outcome was slope of RKF decline, calculated as mean of urinary creatinine and urea clearances. Secondary outcomes included slope of urine volume decline and time from PD initiation to anuria. RESULTS: The study included 151 participants (79 early start, 72 late start). The slope of RKF decline was slower after PD initiation (-2.69±0.18mL/min/1.73m2/yr) compared to before PD (-4.09±0.33mL/min/1.73m2/yr; change in slope +1.19 mL/min/1.73m2/yr, 95%CI 0.48-1.90, p<0.001). In contrast, urine volume decline was faster after PD commencement (-0.74±0.05 L/yr) compared to beforehand (-0.57±0.06L/yr; change in slope -0.18L/yr, 95%CI -0.34--0.01, p = 0.04). No differences were observed between the early- and late-start groups with respect to RKF decline, urine volume decline or time to anuria. CONCLUSIONS: Initiation of PD was associated with a slower decline of RKF compared to the pre-dialysis period.


Assuntos
Rim/fisiopatologia , Diálise Peritoneal , Idoso , Anuria/etiologia , Creatinina/urina , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Humanos , Falência Renal Crônica/patologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Ureia/urina
12.
Nat Commun ; 11(1): 5760, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188202

RESUMO

The high density of macromolecules affecting proteins due to volume exclusion has been discussed in theory but numerous in vivo experiments cannot be sufficiently understood taking only pure entropic stabilization into account. Here, we show that the thermodynamic stability of a beta barrel protein increases equally at all atomic levels comparing crowded environments with dilute conditions by applying multidimensional high-resolution NMR spectroscopy in a systematic manner. Different crowding agents evoke a pure stabilization cooperatively and do not disturb the surface or integrity of the protein fold. The here developed methodology provides a solid base that can be easily expanded to incorporate e.g. binding partners to recognize functional consequences of crowded conditions. Our results are relevant to research projects targeting soluble proteins in vivo as it can be anticipated that their thermodynamic stability increase comparably and has consequently to be taken into account to coherently understand intracellular processes.


Assuntos
Substâncias Macromoleculares/química , Espectroscopia de Ressonância Magnética , Estabilidade Proteica , Bacillus subtilis/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Hidrodinâmica , Modelos Moleculares , Dobramento de Proteína , Termodinâmica , Ureia/farmacologia
13.
Aquat Toxicol ; 229: 105621, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33129562

RESUMO

As one of the main toxic substances in aquaculture water, ammonia causes seriously physiological harm to aquatic animals. In order to investigate the effects of ammonia exposure on the antioxidant defense, immune response, and NF-κB signaling pathway in Chinese Strip-necked Turtle (Mauremys sinensis), we designed two experimental groups (control and 6.45 mM ammonia), and sampled at 6 h, 24 h, 48 h, re 24 h (recover 24 h), and re 48 h. The results showed that the blood ammonia (BA) content was significantly increased when the turtles were subjected to ammonia, and the activities of cholinesterase (CHE) and aspartate aminotransferase (AST) in the serum also showed a significant upward trend. The malondialdehyde (MDA) content continuously increased during ammonia exposure, and more than doubled at 48 h compared with the control group. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT) and their corresponding relative mRNA expression levels in the liver during ammonia exposure were obviously increased when compared to the control group, but most decreased to the normal levels at re 48 h. In addition, the relative mRNA and protein expression levels of NF-E2 related factor 2 (Nrf2) showed similar up-regulation patterns to antioxidase during ammonia exposed periods; whereas kelch-like ECH-binding protein 1 (Keap1), as Nrf2 negative regulator, showed opposite patterns. Moreover, the relative mRNA expression levels of heat shock proteins (HSP70, HSP90) significantly elevated upon the exposure of ammonia. Furthermore, ammonia increased the relative mRNA and protein expression levels of p50 and p65 at different exposed times. The reative mRNA expression levels of immune cytokines (BAFF and IL-6) were upregulated during ammonia exposured time, while there was a decline but did not return to normal levels, in the recovery periods. Taken together, these results indicated that antioxidation, immunity, and NF-κB signaling played a certain protective role for Mauremys sinensis under ammonia exposure. Our results will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in turtles.


Assuntos
Amônia/toxicidade , Antioxidantes/metabolismo , Exposição Ambiental , NF-kappa B/metabolismo , Transdução de Sinais , Tartarugas/imunologia , Amônia/sangue , Animais , Aspartato Aminotransferases/sangue , Colinesterases/sangue , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Malondialdeído/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transcrição Genética/efeitos dos fármacos , Tartarugas/sangue , Tartarugas/genética , Tartarugas/urina , Ureia/urina , Poluentes Químicos da Água/toxicidade
14.
Sci Rep ; 10(1): 16687, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33028894

RESUMO

Eukaryotic complex phototrophs exhibit a colorful evolutionary history. At least three independent endosymbiotic events accompanied by the gene transfer from the endosymbiont to host assembled a complex genomic mosaic. Resulting patchwork may give rise to unique metabolic capabilities; on the other hand, it can also blur the reconstruction of phylogenetic relationships. The ornithine-urea cycle (OUC) belongs to the cornerstone of the metabolism of metazoans and, as found recently, also photosynthetic stramenopiles. We have analyzed the distribution and phylogenetic positions of genes encoding enzymes of the urea synthesis pathway in eukaryotes. We show here that metazoan and stramenopile OUC enzymes share common origins and that enzymes of the OUC found in primary algae (including plants) display different origins. The impact of this fact on the evolution of stramenopiles is discussed here.


Assuntos
Ornitina/metabolismo , Estramenópilas/metabolismo , Ureia/metabolismo , Animais , Evolução Biológica , Bases de Dados Genéticas , Filogenia , Simbiose/fisiologia
15.
PLoS One ; 15(10): e0241481, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33119693

RESUMO

The application of controlled release urea (CRU) has been proposed as a crucial method to reduce the adverse environmental effects induced by conventional urea (CU). Yet, a systematic and quantitative analysis on how CRU affects staple crop production including wheat (Triticum aestivum L.), maize (Zea mays L.), and rice (Oryza sativa L.) is lacking. Here, a meta-analysis was conducted to determine how CRU influences soil chemical properties, total nitrogen (TN) uptake, grain yield, and nitrogen use efficiency (NUE) of staple crop in China. The results indicated that CRU application significantly increased soil organic carbon (SOC), TN, and available nitrogen (AN) by 5.93%, 3.89% and 13.98% respectively overall, while soil pH showed no significant changes. Compared to the application of CU, applying CRU significantly increased grain yield by 7.23%, which was mainly owing to the higher TN uptake (9.13%) across all the studies. In addition, the application of CRU significantly increased NUE, nitrogen agronomy efficiency (NAE), utilization rate of nitrogen fertilizer (NUR), and nitrogen physiological efficiency (NPE) by an average of 23.4%, 34.65%, 25.83% and 15.8% respectively which could be attributed to the slow nitrogen (N) release characteristics of CRU. The positive effect of CRU on grain yield and NUE of staple crop was greatest when the content of SOC and TN were extremely low, indicating that it was most effective to improve grain production of infertile soil by applying CRU. The finding of this study indicated that the application of CRU should be promoted for grain production, especially for infertile soil.


Assuntos
Grão Comestível/efeitos dos fármacos , Grão Comestível/metabolismo , Nitrogênio/metabolismo , Ureia/farmacologia , Transporte Biológico/efeitos dos fármacos , Preparações de Ação Retardada , Grão Comestível/crescimento & desenvolvimento , Solo/química
16.
Phys Chem Chem Phys ; 22(43): 25165-25176, 2020 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-33124623

RESUMO

This work reports the experimental measurements of solvent acidity (SA), basicity (SB), and solvent dipolarity and polarizability (SPP) for water solutions with urea (U) and its molecular derivatives, monomethyl-urea (MU), 1,3-dimethyl-urea (DMU) and tetramethyl-urea (TMU). These solvatochromic parameters are applied to understanding the variation of indexes of refraction and densities and other physico-chemical properties reported for these solutions. These properties are well correlated to the SA, SB, and SPP solvent parameters of these solutions. As a result, from the characterization of the physico-chemical properties, one can infer that urea and its molecular derivatives are mainly modifiers in the structure of liquid water. The solvatochromic parameters indicate the possible existence of different mechanisms in the denaturation process of proteins in these urea/water solutions.


Assuntos
Desnaturação Proteica , Solventes/química , Ureia/química , Água/química , Concentração de Íons de Hidrogênio , Ureia/análogos & derivados
17.
G Ital Nefrol ; 37(5)2020 Oct 05.
Artigo em Italiano | MEDLINE | ID: mdl-33026202

RESUMO

We report the case of a 68-year-old patient who arrived at the hospital with a fever and a cough for 7 days, a history of high blood pressure and chronic kidney failure stage 2 according to CKD-EPI (GFR: 62 ml/minute with creatinine: 1.2 mg/dl). Home therapy included lercanidipine and clonidine. A chest radiograph performed in the emergency department immediately showed images suggestive of pneumonia from COVID-19, confirmed in the following days by a positive swab for coronavirus. Kidney function parameters progressively deteriorated towards a severe acute kidney failure on the 15th day, with creatinine values of 6.6 mg/dl and urea of 210 mg/dl. The situation was managed first in the intensive care unit with CRRT cycles (continuous renal replacement therapy) and then in a "yellow area" devoted to COVID patients, where the patient was dialyzed by us nephrologists through short cycles of CRRT. In our short experience we have used continuous techniques (CRRT) in positive patients hemodynamically unstable and intermittent dialysis (IRRT) in our stable chronic patients with asymptomatic COVID -19. We found CRRT to be superior in hemodynamically unstable patients hospitalized in resuscitation and in the "yellow area". Dialysis continued with high cut-off filters until the normalization of kidney function; the supportive medical therapy has also improved the course of the pathology and contributed to the favorable outcome for our patient. During the COVID-19 pandemic, our Nephrology Group at Savona's San Paul Hospital has reorganized the department to better manage both chronic dialyzed patients and acute patients affected by the new coronavirus.


Assuntos
Lesão Renal Aguda/terapia , Betacoronavirus , Infecções por Coronavirus/complicações , Pandemias , Pneumonia Viral/complicações , Lesão Renal Aguda/diagnóstico por imagem , Lesão Renal Aguda/etiologia , Lesão Renal Aguda/fisiopatologia , Idoso , Anti-Hipertensivos/uso terapêutico , Antivirais/uso terapêutico , Betacoronavirus/fisiologia , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/fisiopatologia , Infecções por Coronavirus/terapia , Creatinina/sangue , Cuidados Críticos/métodos , Gerenciamento Clínico , Hemodinâmica , Humanos , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Comunicação Interdisciplinar , Falência Renal Crônica/complicações , Masculino , Equipe de Assistência ao Paciente , Isolamento de Pacientes , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/fisiopatologia , Pneumonia Viral/terapia , Diálise Renal/métodos , Respiração Artificial , Ureia/sangue
18.
Sci Rep ; 10(1): 16082, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32999417

RESUMO

High-protein diets contribute to an increase in urea follicular concentrations associated with decreased fertility. Urea has been shown to interfere with the epidermal growth factor (EGF)/EGFR system, which has been shown to have a beneficial effect during in vitro maturation (IVM) of oocytes. Of note, the number of cumulus-oocyte complexes (COCs) in the maturation medium can change the maturation and the developmental competence of COCs. Therefore, it was hypothesized that, the presence of urea and EGF may have a differential effect on the depletion/appearance of AAs and competence of COCs matured individually (I-IVM system) or in groups (G-IVM system). In the G-IVM system, COCs increased consumption (depletion) of AAs compared with other groups in the presence of high-level urea (40 mg/dl) + EGF (10 ng/ml). In the I-IVM system, the non-cleaved COCs depleted more AAs than the cleaved COCs, in particular in the presence of urea. The combination of urea and EGF increased the depletion of AAs in the G-IVM system. However, the EGF abrogated the urea-induced depletion of AAs by the I-IVM COCs. The use of N-acetyl-L-cysteine as an EGFR inhibitor canceled urea-induced depletion of AAs. This shows the inhibiting effect of urea over the EGF/EGFR system. In the presence of urea + EGF, COCs had a lower degree of developmental competence than control in both I- and G-IVM systems. Arginine had the best predictive power to identify highly competent COCs in the G-IVM system, while glutamine was the best predictor of the cleavage in the I-IVM system. In conclusion, this multi-level study shows that COCs matured individually or in groups may have different association with AAs metabolism. These findings provide new insights into the relationships between AA metabolism and the subsequent developmental competence of COCs.


Assuntos
Aminoácidos/metabolismo , Oócitos/metabolismo , Aminoácidos Essenciais/metabolismo , Animais , Bovinos , Meios de Cultura , Células do Cúmulo/citologia , Células do Cúmulo/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Maturação in Vitro de Oócitos/métodos , Técnicas In Vitro , Simulação de Acoplamento Molecular , Análise Multinível , Oócitos/citologia , Oócitos/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ureia/metabolismo , Ureia/farmacologia
19.
PLoS One ; 15(10): e0240925, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112905

RESUMO

Urease inhibitor (UI) and nitrification inhibitor (NI) can reduce N losses from agricultural soils but effects of inhibitors on N cycle are unclear. A field experiment was conducted with maize to test effects of UI (N-(n-Butyl) thiophosphoric, NBPT) and NI (3,4-dimethylepyrazolephosphate, DMPP) on N uptake and N-cycling soil microbes. Five treatments were imposed: no N fertilizer input (CK), conventional fertilization (CF) and 80% of urea input with NBPT (80%U+UI), with DMPP (80%U+NI) and with half NBPT and half DMPP (80%U+1/2(UI+NI)). There were no significant differences in biomass between 80%U+UI, 80%U+NI and CF but harvest index was increased under 80%U+UI and 80%U+NI. Compared to CF, N use efficiency of grain under 80%U+UI was increased by 7.1%, whereas grain yield and N uptake under 80%U+1/2(UI+NI) were decreased by 8.2% and 9.4%, respectively. The peak soil [Formula: see text] content was at about 15 days after fertilization (DAF) under CF but 30 DAF under the inhibitor treatments. In soils of 80%U+UI, the activities of urease and nitrate reductase were decreased between 15-45 DAF and between 5-30 DAF. The abundance of N-cycling soil microbes was affected: 80%U+UI and 80%U+NI reduced the copies of the amoA AOA and nir genes at about 15 days and reduced the copies of the amoA AOB gene at about 30 days. Correlation analysis indicated that there were significant positive relationships between amoA AOB gene and [Formula: see text], as well as between nirK gene and [Formula: see text]. Overall, urea applied with NBPT has greater potential for improving maize N use efficiency and inhibiting nitrification under reduced fertilizer-N applications.


Assuntos
Microbiota/efeitos dos fármacos , Nitrogênio/metabolismo , Compostos Organofosforados/administração & dosagem , Ureia/administração & dosagem , Zea mays/efeitos dos fármacos , Zea mays/metabolismo , Agricultura/métodos , Amônia/metabolismo , Biomassa , China , Fertilizantes , Nitrificação/efeitos dos fármacos , Óxido Nitroso/metabolismo , Solo/química , Microbiologia do Solo , Urease/metabolismo
20.
J Environ Qual ; 49(6): 1453-1466, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33058171

RESUMO

Cattle excreta and nitrogen (N) fertilizer deposited on tropical grasslands are important sources of ammonia (NH3 ) emission. We conducted three field trials (wet, intermediate, and dry conditions) to quantify NH3 emissions from urea fertilizer and simulated excretions of heifer urine and dung on warm-climate grasslands in Brazil. Heifer excreta were derived from pastures of palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster 'Marandu'] under three forms of N supply (without or with N fertilization [0 or 150 kg N ha-1  yr-1 ] or mixed with forage peanut [Arachis pintoi 'Amarillo']). Cumulative NH3 -N emissions across rainfall conditions were 7.6-16.6% (mean, 11.7%) for urine, 1.4-2.9% (mean, 2.0%) for dung, and 11.2-20.5% (mean, 14.8%) for urea. Ammonia loss from urine was significantly greater than from dung under all rainfall conditions. Emission from urine and dung differed from those when urea was applied on palisadegrass. There were greater NH3 emissions from urine in the wetter times of the year. Heifer excreta from N-fertilized pasture had greater NH3 emission than excreta from the grass-legume mixture and unfertilized palisadegrass. Urea applied on palisadegrass presented greater NH3 emissions in wet rainfall conditions compared with dry conditions but did not differ from intermediate conditions. Our study showed that N-fertilized systems increase N losses as NH3 emission from excreta, and emissions from urea fertilizer must be included in this system. Heifer excreta and urea fertilizer deposited on warm-climate grasslands increased the NH3 emissions mainly under wet conditions.


Assuntos
Amônia , Nitrogênio , Afeto , Amônia/análise , Animais , Brasil , Bovinos , Feminino , Nitrogênio/análise , Ureia
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