Urea Concentration Research Articles

Quantitative Raman Spectroscopy of Urea and Thiourea in the Reaction Mixtures of Allantoin and 4,5‐Dihydroxyimidazolidine‐2‐Tione Formation

ABSTRACTThe present work introduces a new approach to quantitative determine the reagent concentrations (thiourea and urea) using in situ Raman spectroscopy in the reaction mixture exemplified by the reactions of formation of allantoin and 4,5‐dihydroxyimidazolidine‐2‐thione. The approach comprises the use of a commercially available immersion probe (MarqMetrix Process Elite BallProbe with sapphire lens) as a standard for the immersion probe band at 790 cm−1 of optical glass. This leads to a linear dependence of the ratio of the intensity of non‐overlapping analyte bands at 1003 cm−1 of ‐C‐N‐ vibrations in urea to the one of the 790 cm−1 immersion probe band on the concentration of urea in the test solution. The definable method parameters such as precision (repeatability and reproducibility), linearity, limit of detection (LoD), limit of quantitation (LoQ), and accuracy were determined. The quantitative Raman spectroscopy method is linear, precise within the range of determined concentrations from 0.75 to 2.00 M and can be used to calculate the kinetics of allantoin formation. Using thiourea as an example, it is shown that despite the partial overlap of the analyte band at 730 cm−1 of the ‐C=S vibrations of thiourea with the immersion probe band at 790 cm−1, the method to determine thiourea in the reaction of 4,5‐dihydroxyimidazolidine‐2‐thione preparation is also linear and precise in the range of determined concentrations from 0.10 to 1.57 M.

Transferability across countries of equations developed using milk mid-infrared spectroscopy to estimate daily body condition score change in dairy cows

Routine milk samples are commonly subjected to spectroscopic analysis within the mid-infrared (MIR) region of the electromagnetic spectrum to estimate macro-constituents of milk like fat, protein, lactose, and urea content. These spectra, however, can also be used to predict other traits, such as daily body condition score (BCS) change. The objective of the present study was to assess the transferability across countries of equations to predict daily body condition score change (ΔBCS) developed using milk MIR data collected in Ireland and in Canada. Body condition was scored on a scale from 1 (emaciated) to 5 (obese) in both countries. A total of 347,254 BCS records from 80,400 Canadian cows were available along with 73,193 BCS records from 6,572 Irish cows. Partial least squares regression (PLSR) and neural networks (NN) were separately used to predict daily ΔBCS. Two scenarios were studied 1) using Canadian and Irish data combined as the calibration data set to predict daily ΔBCS in Canada and in Ireland separately, and 2) Canadian and Irish data used separately to predict daily ΔBCS in each country separately. These prediction methods were applied to data with and without pretreatment (i.e., first derivative of the spectrum) as well as with and without standardizing daily ΔBCS across countries. For all the scenarios investigated, the correlation between actual and predicted daily ΔBCS when calibrated and validated (using cross-validation) in the same country ranged from 0.92 to 0.94, and from 0.85 to 0.87 for the Canadian and Irish data sets, respectively. When the data from Canada and Ireland were combined in the calibration process to predict daily ΔBCS, the correlations between actual and predicted ΔBCS were ≥ 0.90 and ≥ 0.80 for Canadian and Irish daily ΔBCS, respectively indicating no improvement in predictive ability. Predictive performance when calibrated using just Canadian data and validated using just Irish data was poor, and vice versa. Nonetheless, when developing equations for a country for which a limited database (i.e., 100 records) of gold standard and MIR data were available, predictive performance improved when the limited database was supplemented with the large data set from the other country. In general, for some of the investigated scenarios, standardizing the daily ΔBCS data within country before undertaking the calibration improved prediction accuracy. In conclusion, the benefit of merging data from different countries, at least based on the trait (i.e., daily ΔBCS) and countries (i.e., Ireland and Canada) considered in the present study were limited and, in cases, counter-productive.

Effects of Composite Probiotic Food on Urinary, Serum Biochemical and Oxidative Stress Parameters in a Urolithiatic Rat Model.

Prevention, management or cure of diseases through dietary approaches is becoming increasingly important. Research suggests that probiotic, oxalate-degrading Lactobacillus species administered via a milk and cereal food can prevent kidney stones while also addressing nutritional deficiencies and maintaining essential calcium levels. This study investigates the effect of a composite probiotic milk beverage on urolithiatic rats. Probiotic milk-barley beverage (PMBB) was prepared by fermentation of milk enriched with barley (Hordeum vulgare) flour using starter culture containing oxalate-degrading probiotic strains (Lacticaseibacillus rhamnosus strains MTCC5945 and MTCC25062, Lactobacillus helveticus MTCC5463 and Lactiplantibacillus plantarum M11). Cumin and common salt were used as flavourings. Unfermented milk-barley base (C) served as control. Wistar rats were divided in four groups (N=6). Normal control (NC) group received normal rat diet, and to induce kidney stones, ethylene glycol (0.75 %) and ammonium chloride (1 %) were administered to the disease control (DC) group, PMBB and control (C) groups for 28 days. PMBB and C groups received 1 mL of probiotic milk and barley beverage and unfermented milk-barley base from day 15 to day 28. Indicators of urolithiasis were studied. PMBB significantly (p<0.05) increased urine output, decreased urine oxalate concentrations and increased creatinine, calcium and uric acid concentrations. Serum parameters such as concentrations of calcium, uric acid, urea and creatinine increased significantly (p<0.05) in DC rats, but decreased significantly (p<0.05) in the PMBB group. In addition, serum concentrations of magnesium and osteopontin decreased more significantly in DC rats than in the PMBB ones. The increase in malondialdehyde and decrease in reduced glutathione concentrations observed in the DC group were significantly lower in the PMBB group. The histomorphology of the kidney tissue of DC rats showed calcium oxalate crystal aggregates in the tubules, indicators of renal injury, tubular dilatation, enlarged urinary space and shrunken glomeruli. The PMBB group showed an improvement in the renal histological architecture. Analysis of the caecal digesta of the rats showed a significantly (p<0.05) higher mass fraction of fatty acids (acetic and propionic) in the treatment group. The results show the potential of PMBB in the dietary control of urolithiasis. This study focuses on the antiurolithiatic prospect of a composite probiotic milk beverage produced with oxalate-degrading culture. It also points to a new functional food form that shows promising health benefits in nutrition of patients with urolithiasis.

The Effect of Different Forms of Solid Feed on Biochemical Parameters in Blood Plasma of Calves

Abstract The study examined how different solid feeds affected the biochemical parameters in calf plasma. The experiment involved a control group and three test groups of calves, each fed with a different starter mixture. The results showed significant differences in some biochemical parameters between the feeding groups. Calves in groups P1 and P3 had a statistically higher glucose concentration in blood plasma compared to group C. Calves from group P3 had a higher concentration of urea in blood plasma than calves from group C. Calves in groups P1 and P3 also had higher concentrations of total protein and globulin in blood plasma compared to group C. The concentration of inorganic phosphate in the blood plasma of calves from group P3 was significantly higher than that of group C. Female calves in the experimental groups showed a lower concentration of NEFA at three months of age compared to the control group. It was concluded that feeding calves with a starter mixture containing whey and easily digestible protein had a positive effect on the nutritional status and energy balance of the calves.

Investigation of the concentration and isotopic composition of Cu, Fe and Zn in human biofluids in the context of Alzheimer’s disease via tandem and multi-collector inductively coupled plasma-mass spectrometry

Studies on essential trace elements in the context of Alzheimer’s disease (AD) concluded that Cu, Fe and Zn interact with amyloid-β, accelerating plaque formation in the brain. Additionally, Cu and Fe in the vicinity of plaques produce reactive oxygen species (ROS) resulting in oxidative stress, whereas Zn plays a role in the antioxidant defence as a co-factor for antioxidants. In this work, the Cu, Fe and Zn concentrations and isotope ratios were determined in whole blood, blood serum and cerebrospinal fluid of 10 patients diagnosed with AD and 8 control individuals, using tandem (ICP-MS/MS) and multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS), respectively. In whole blood and blood serum of AD patients, a heavier Cu isotopic composition was observed (significant for whole blood only) compared to controls. Albumin levels in cerebrospinal fluid tend to increase with age, which could indicate an increased leakiness of the blood-brain barrier. In cerebrospinal fluid, a large variability was observed for the Cu and Fe isotope ratios, potentially resulting from that leakiness at the blood-brain barrier. Therefore, potential effects of AD on the concentration and isotopic composition of essential elements in cerebrospinal fluid related to amyloid-β formation could be hidden. Finally, in blood serum, Zn, urea and creatinine concentrations showed an increase with age and showed a significant difference between sexes.

Controlled synthesis and electrochemical characterization of Co3V2O8 hexagonal sheets for energy storage applications

This work explores the hydrothermal synthesis of Co3V2O8 hexagonal sheets and their effects on the structure and electrochemical properties of the electrode material, with a focus on various urea concentrations. The prepared materials were extensively characterized through a variety of imaging and electrical techniques, such as asymmetric supercapacitor studies, cyclic voltammetry (CV), Galvanostatic charge-discharge (GCD) analysis, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). Morphological analyses revealed that distinct hexagonal sheets formed based on the urea content. XPS analysis has provided information about the oxidation states and chemical composition of the produced materials. The high capacitance of 293 F/g with an energy density of 14.68 Wh/kg at an applied current density of 1 mA/cm2 over CVO-0.6MU sample demonstrates the electrochemical capabilities of hexagonal sheets of Co3V2O8 as electrode materials for supercapacitor, as demonstrated by electrochemistry research such as GCD, CV, and EIS. Furthermore, we were able to attain a high capacitive retention of approximately 99 % columbic efficiency up to 20,000 cycles, as well as a high power density exceeding CVO-0.6MU, or 142 W/kg. These findings showed how highly feasible our as-synthesized CVO-0.6MU electrode material is as an energy storage device. The research carried out on asymmetric supercapacitor provides more evidence of the stable and promising capacitive performance of the synthetic materials, Additionally effect of the temperature on ASC were studied. This extensive work offers crucial details regarding the electrochemical characteristics and regulated manufacture of Co3V2O8 hexagonal sheets, which may find application in future cutting-edge energy storage technologies.

Effects of exposure to volatile organic compounds (VOCs) content from paint on automobile paint workers in Nsukka, South Eastern Nigeria

BackgroundVolatile organic compounds (VOCs) fume in the workplace can act as an inducing agent to many health disorders. ObjectivesThis work investigated the effects of exposure to VOCs content from paint on the automobile paint workers in South Eastern Nigeria. MethodsA total of fifty (50) respondent participated in the study. Following the completion of informed consent form and well-structured questionnaire, blood samples were drawn and used for biochemical analysis. ResultsThe results of the haematological analysis showed a significant (p < 0.05) increase in white blood cell (WBC) cluster of differentiation 4 (CD4), and platelet (PLT), and a significant (p < 0.05) decrease in packed cell volume (PCV), hemoglobin (HB), lymphocytes (LYM) and eosinophil (EOS) of the exposed automobile paint workers compared to the control (unexposed workers). Results also showed significant (p < 0.05) increase in liver marker indices; alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin (TB) and albumin (ALB) as well as significant (p < 0.05) decrease in Alkaline phosphatase (ALP), total protein (TP), direct bilirubin (DB). There was significant (p < 0.05) increase in urea, creatinine, potassium (K+), uric acid and nitric oxide concentrations and decrease in sodium (Na+) and bicarbonate (HCO3−) Again, results showed significant increase in Glutathione (GSH), and Glutathione peroxidase (GPx) and significant (p < 0.05) decrease in Superoxide dismutase (SOD) and Catalase (CAT). The Malondialdehyde MDA concentration showed varied significant (p < 0.05) difference based on ages. There was significant (p < 0.05) increase in luteinizing hormone (LH) and Follicle stimulating hormone (FSH), and significant (p < 0.05) decrease in the Testosterone (TET) concentrations of the exposed automobile paint workers compared to the unexposed workers. ConclusionsResult of this study suggests a toxic outcome due to exposure to VOCs in spray paint workers.

Study on Ship Exhaust Gas Denitrification Technology Based on Vapor-Phase Oxidation and Liquid-Phase Impingement Absorption

A system combining gas-phase oxidation and liquid-phase collision absorption for removing NO from marine diesel engine exhaust was proposed. This method was the first to utilize different physical states of the same mixed solution to achieve both pre-oxidation and impingement reduction absorption of exhaust gases. During the pre-oxidation stage, a mixture of (NH4)2S2O8 and urea solution was atomized into a spray using an ultrasonic nebulizer to increase the contact area between the oxidant and the exhaust gas, thereby efficiently pre-oxidizing the exhaust gas in the gas phase. In the liquid-phase absorption stage, the (NH4)2S2O8 and urea solution was used in an impingement absorption process, which not only enhanced gas–liquid mass transfer efficiency but also effectively inhibited the formation of nitrates. Experimental results showed that, without increasing the amount of absorbent used, the maximum NO removal efficiency of this method reached 97% (temperature, 343 K; (NH4)2S2O8 concentration, 0.1 mol/L; urea concentration, 1.5 mol/L; NO concentration, 1000 ppm; pH, 7; impinging stream velocity, 15 m/s), compared to 72% using the conventional liquid-phase oxidation absorption method. Additionally, this method required only the addition of a nebulizer and two opposing nozzles to the existing desulfurization tower to achieve simultaneous removal of sulfur and nitrogen oxides from the exhaust gas, with low retrofitting costs making it favorable for practical engineering applications.

Feeding almond hulls to light lambs: Effects on growth performance, digestive utilization and blood metabolites

The effects of including almond hulls (AH) in the concentrate fed to light lambs on animal performance, diet utilization, and blood metabolites. Three isonitrogenous and isoenergetic concentrates were formulated with either 0 (control), 6 (AH6) or 12 (AH12) g of AH per 100 g (fresh matter basis). Thirty Manchega breed lambs (15 males and 15 females; 12.3 ± 0.18 kg body weight (BW)) were distributed into six homogeneous groups according to BW (3 groups of each sex), which were randomly assigned within sex to each experimental concentrate. Lambs were fed concentrate and barley straw ad libitum until reaching about 23.0 kg BW. There were no differences (P ≥ 0.182) between groups in final BW, intake of concentrate and straw, and feed conversion rate. Average daily gain and digestibility of dry matter and crude protein tended (P < 0.10) to decrease by the AH inclusion in the concentrate. Lambs fed AH12 showed greater (P < 0.05) urinary losses than those fed the control concentrate (15.4 and 11.5 g per 100 g of N intake, respectively), despite the similar N intake in all groups. Feeding AH did not affect (P ≥ 0.213) blood concentrations of albumin, globulins, urea, creatinine, glucose, total bilirubin and cholesterol or blood activities of hepatic enzymes. The post-mortem analysis revealed no differences among groups in pH and total volatile fatty acids (VFA) concentrations in the rumen of lambs, but NH3-N concentrations were lower (P < 0.05) in the lambs fed the concentrates with AH. In addition, lambs fed AH12 diet had lower (P < 0.05) molar proportions of propionate and greater (P < 0.05) proportions of butyrate compared with lambs fed control and AH6 concentrate. In general, no concentrate x sex interactions were observed, and sex had no effect on the measured parameters except for some differences in ruminal VFA profile. In conclusion, AH can be included at in light lambs’ concentrate up to 12 g per 100 g of concentrate without impairing animal growth.

Comparison of hemodialysis urea clearance using spent dialysate and Kt/Vurea equations.

Dialysis adequacy is traditionally calculated from pre- and post-hemodialysis session serum urea concentrations and expressed as the urea reduction ratio, or Kt/Vurea. However, with increasing hemodiafiltration usage, we wished to determine whether there were any differences between standard Kt/Vurea equations and directly measured spent dialysate urea clearance. Urea clearance was measured from collected effluent dialysate and compared with various other methods of Kt/Vurea calculation, including change in total body urea from measuring pre- and post-total body water with bioimpedance and the Watson equation, by standard Kt/V equations, and online clearance measurements using effective ionic dialysance (OLC). We compared urea clearance in 41 patients, 56.1% male, mean age 69.3 ± 12.6 years with 87.8% treated by hemodiafiltration. Reduction in total body urea was greater when estimating changes in total body urea, compared to measured dialysate losses of 58.4% (48.5-67.6) vs 71.6% (62.1-78), p < 0.01. Sessional urea clearance (Kt/Vurea) was greater using the online Solute-Solver program compared to OLC, median 1.45(1.13-1.75) vs 1.2 (0.93-1.4), and 2nd generation Kt/V equations1.3 (1.02-1.66), p < 0.01, but not different from estimated total body urea clearance 1.36 (1.15-1.73) and dialysate clearance 1.36 (1.07-1.76). The mean bias compared to the Solute-Solver program was greatest with OLC (-0.25), compared to second-generation equations (-0.02), estimated total body clearance (-0.02) and measured dialysate clearance (-0.01). This study demonstrated that the result from equations estimating urea clearance indirectly from pre- and postblood samples from hemo- and hemodiafiltration treatments was highly correlated with direct measurements of dialysate urea clearance.

Changes in the quality indicators of cows› milk depending on feeding the feed additive in different doses

Relevance. The quality of milk depends on the season, the breed of animals, the state of metabolism, the features of feeding technology and maintenance, and the feed additives fed. The doses of their feeding can affect the composition of milk. Methods. The content of mass fractions of fat, protein, lactose, its acidity, as well as the content of urea, acetone, and beta-hydroxybutyric acid in milk were determined.Results. The introduction of an experimental feed additive into the feeding rations of dairy cows had an impact on the change in the values of the indicators studied in milk. Moreover, not all the studied indicators changed under the influence of feeding this supplement. So, if we correlate the results obtained with changes in control, then, according to the authors, it is correct to talk about its significant effect on the change in the value of the mass fraction of protein in milk and the values of milk acidity: feeding in the diet of a feed additive at a dose of 1.0 kg and 1.5 kg leads to a significant increase in the mass fraction of protein in milk by 0.18% (p ˂ 0.01) and 0.15% (p ˂ 0.01), respectively, as well as a significant shift in the active acidity of milk to the alkaline side by 1.56% (p ˂ 0.001) and 0.78% (p ˂ 0.05), respectively.

Effects of foliar treatments with urea and nano-urea on the cell walls of Monastrell grape skins

Cell wall composition can be affected by nitrogen availability in the vineyard. Foliar application of urea is effective in supplying nitrogen needs and increasing the nitrogen content of musts. Due to the low recoveries of urea fertilisation, more effective application methods such as the use of nanotechnology are needed. In this work, the effect on the composition of Monastrell grape skin cell walls, after foliar application of urea and amorphous calcium phosphate nano-particles doped with urea was studied. The treatments with urea and nano-urea, although the urea content in the nano-treatment was eight times lower than in the conventional treatment, produce an equivalent modification of the cell wall. In fact, both treatments produced an increase in cell wall thickness and in cell wall composition, contents of proteins, hemicellulose and uronic acids also increased. However, phenolic compounds were not affected and cellulose showed lower concentrations than control grapes. Regarding the spectrophotometric parameters of the wine studied, the anthocyanins content and colour intensity were reduced in wines with both treatments and the total polyphenol index was slightly affected.

The protective effect of fasciotomy combined with hypertonic saline flushing for crush syndrome in rats.

In natural disasters such as earthquakes and landslides, the main problem that wounded survivors are confronted with is Crush Syndrome (CS). The aim of this study was to explore more convenient and effective early treatment measures for it.In the present study, we investigated the protective effect of fasciotomy combined with different concentration of hypertonic saline flushing with CS rats. CS model was prepared by compressing the buttocks and both lowering limbs of rats with 7.5 kg dumbbell for 4 hours. The rats were divided into 10 groups, which were normal control group, model group, incision without flushing group, 0.45%, 0.9%, 3%, 5%, 7% saline group, 3%-0.45% and 7%-0.45% saline alternating flushing group respectively. 6 hours after the treatment, the blood was sampled for measurement of the potassium, calcium, AST, ALT, Cr, Urea, myoglobin, and lactic acid content. The blood flow of the compressed tissue and kidneys, the pathological changes of the kidneys and the survival rate of 3%-0.45% saline alternating flushing group were also observed.The experimental results showed that fasciotomy alone for treatment cannot improve the presentation of CS of rats. Instead, hypertonic saline flushing significantly improved the AST, ALT, Cr, Urea indices, blood flow of muscles and kidneys. It also enormously decreased the blood K+, myoglobin, lactic acid concentration and slight increased the blood Ca2+. Among them, alternating flushing with 3%-0.45% saline had the best therapeutic effect on CS. Finally, it can be found that 3%-0.45% saline treatment regimen dramatically raised the survival rate of CS rats.All in all, this study suggests that fasciotomy combined with hypertonic saline flushing is a good therapeutic approach for CS.

Hydrogen bond producers in powerful protic ionic liquids for enhancing dissolution of natural cellulose

AbstractThe manipulation of hydrogen bonding within protic ionic liquids is conducive to conquering the robust hydrogen bonding interactions in cellulose for its effective dissolution, but it is a great challenge to establish the delicate balance of hydrogen bonding network between solvent and cellulose. Herein, we proposed the concept of “hydrogen bond producers” for urea molecules in 1,1,3,3‐tetramethylguanidinium methoxyacetate acid ([TMGH][MAA]) to enhance the dissolution of cellulose. The optimization of physicochemical properties for [TMGH][MAA] solvent as a function of urea concentration revealed a remarkable increase in cellulose solubility from 13% to 17% (w/w) by adding only 0.25 wt% urea, highlighting the efficiency of [TMGH][MAA] as a powerful solvent for the dissolution of cellulose. The experimental and simulation results verified that the significant improvement on dissolution of cellulose was attributed to the hydrogen bonding interaction of urea molecules with ion pairs and part of free ions, reducing the interference with the active ions bonded to cellulose. Furthermore, the considerable enhancement on comprehensive properties of regenerated cellulose films demonstrated the effectiveness of [TMGH][MAA]/urea solvent. The concept of “hydrogen bond producers” presented here opens a new avenue for significantly enhancing the dissolution of natural cellulose, promoting the sustainable development in large‐scale processing of cellulose.

Inhibitory effect of calcium carbonate precipitation induced by Triton X-100 and microorganisms on coal dust

During underground tunnel construction, dust endangers the safety and health of workers. Microbially induced calcium carbonate precipitation (MICP) represents a novel green dust suppression technology for addressing coal dust pollution, capable of effectively mitigating coal dust pollution. Nevertheless, the concentration of urease will exert a certain influence on the performance of MICP to some extent. Therefore, how to improve the efficiency of urease activity on coal dust suppression is a popular research topic. In this study, based on MICP technology, the properties of microbial dust suppression materials were investigated through contact angle, surface tension, and unconfined compressive strength (UCS) tests in combination with molecular dynamics simulations, scanning electron microscopy, and X-ray diffraction using Bacillus megaterium and the nonionic surfactant Triton X-100. The results demonstrate that when the concentration of the bacterial solution is 20 % and the concentrations of urea and calcium chloride are 0.7 mol·L–1, the addition of 1 % Triton X-100 can increase the yield of calcium carbonate to 21.83 %, enhance the structural density of the gel, and increase the UCS by 15.63 %. The calcite and quartz formed on the coal dust surface improved its wettability with a contact angle of only 22°, showing an excellent dust-suppression effect. These research findings serve as a reference for enhancing the MICP dust suppression efficacy and have significant implications for the development and application of microbial dust-suppression agents. This dust suppression method has potential applications in quarries and underground environments.

Application of N-doped NiCo2O4/NiO/Co3O4 composites rich in oxygen vacancies in electromagnetic wave absorption

In this work, N-doped and oxygen vacancy-rich NiCo2O4/NiO/Co3O4composites are synthesized by the direct calcination method. Noticeably, by changing the additive concentrations of urea dissolved in DMF (N-N dimethylformamide), the electromagnetic wave (EMW) absorption abilities of NiCo2O4/NiO/Co3O4composite effectively. A maximum reflection loss (RLmax) value at 12.94 GHz for a 2.8 mm thick sheet is -29.76 dB, while its effective absorption bandwidth (RL < -10 dB) reaches 4.21 GHz. In-depth research of possible mechanisms of EMW absorption enhancement. Owing to its simple preparation method and superb EMW absorption properties, the NiCo2O4/NiO/Co3O4composites have a chance to be suitable candidates for high-property EMW absorbers.

Modulating Interfacial Properties in Pseudoternary Microemulsions via Urea Addition: Impact of Cosurfactant on the Reverse Micellar Structure and Interactions.

We have studied the structural and interfacial properties of CTAB/isooctane/alcohol/aqueous urea reverse micelles (RMs) for the first time using time-resolved fluorescence and small-angle X-ray scattering techniques. The chain length of alcohol, used as cosurfactant, has been varied to design three microemulsion systems: CTAB/1-butanol, CTAB/1-hexanol, and CTAB/1-octanol/isooctane/water, at a fixed water loading ratio, w0 = 12. Time-resolved fluorescence anisotropy studies indicate that urea induces micellar aggregation in CTAB/1-butanol and CTAB/1-hexanol RMs but breaks down RM aggregates in CTAB/1-octanol RMs. Urea addition slows down solvation dynamics inside RMs at higher urea concentrations, evident from the longer lifetimes of solvent correlation decay. The underlying changes in microemulsion structure and intermicellar interactions are studied using small-angle X-ray scattering studies. The significant intermicellar interactions were modeled using the sticky hard sphere (SHS) for the CTAB/1-butanol and CTAB/1-hexanol RMs and by using the Macroion model for the CTAB/1-octanol RMs. The two different structural factors highlight the dominance of attractive and repulsive forces, respectively. Although there is no change in RM shape, the combination of urea addition and chain length variation in cosurfactants significantly alters the size and interface in these pseudoternary RMs.

Effects of partial or full replacement of soybean meal with urea or coated urea on intake, performance, and plasma urea concentrations in lactating dairy cows.

We expected mitigation of the hypophagic effects of urea (U) with a coated urea (CU) product that aimed to partially shift urea supply to the post-ruminal gastrointestinal tract. Ruminal release and post-ruminal digestibility of CU was evaluated in vitro, followed by a randomised complete block experiment (54 Holstein-Friesian cows; 177 ± 72 days in milk). Soybean meal (SBM) was partially (PR) or fully (FR) replaced on an isonitrogenous basis by beet pulp and U or CU. Urea sources were included at 12 (U-PR, CU-PR) and 19 (U-FR, CU-FR) g/kg dietary dry matter (DM). Hypophagic effects were similar for U-PR and CU-PR (-11% vs. -7%), and for U-FR and CU-FR (-13% vs. -12%) compared with SBM (average 25.8 kg DM intake/d). Compared with SBM, U-PR and CU-PR reduced yields of milk (-8%) and protein (-12%), U-PR reduced yield of fat (-9%) and fat- and protein-corrected-milk (FPCM; -9%), and CU-PR tended to reduce FPCM yield (-5%). Compared with SBM, U-FR and CU-FR respectively reduced yields of milk (-21%, -22%), protein (-25%, -26%), fat (both -14%), lactose (-20%, -21%), and FPCM (-17%, -19%), and lowered N (-15%, -12%) and feed (-8%, trend, -9%) efficiency. Human-edible protein efficiency approximately doubled with U-PR and CU-PR and approximately tripled with U-FR and CU-FR compared with SBM. Milk composition and plasma urea concentration were similar between U and CU, except for a trend for a greater plasma urea concentration with U-PR compared with CU-PR. Dry matter intake patterns differed for CU-PR compared with U-PR and for CU-FR compared with U-FR, suggesting effects of urea release rate or location on feeding behaviour. Overall, replacing SBM with U or CU reduced DM intake and milk production and affected nutrient efficiencies. Coated urea influenced DM intake pattern but did not affect total DM intake or milk production compared with U.

Fabrication of an amperometric urea biosensor based on chitosan modified pencil graphite electrode

An amperometric biosensor was fabricated by using urease enzyme, graphene oxide (GO), gold nanoparticles (AuNPs) and chitosan (CHIT) composite. Pencil graphite electrode (PGE) was used for the electrodeposition of nanomaterials and the detection of urea. Various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier-transform infrared (FTIR) spectra, UV–visible spectroscopy, zeta-potential and cyclic voltammetry (CV) were used for characterization. The biosensor showed an optimum response at pH 8.0 and 40 °C temperature. The maximum current of the proposed biosensor was due to electron generated at 0.79 V against Ag/AgCl electrode. Fabricated biosensor showed a wide linear range (0.1–1.0 mg/mL) and low limit of detection (0.9956 mg/mL) with satisfactory selectivity, sensitivity (0.00555 μA/mg/mL/cm2), and stability. It was successfully employed for detecting urea concentration in sera samples of healthy individuals and patients with kidney disorders.

The components of arginine and methylarginine metabolism are indicative of altered kidney function in intrauterine growth-restricted neonates.

Intrauterine fetal growth restriction (IUGR) affects up to 10% of all pregnancies. Severe IUGR is associated with impaired kidney development, reduced nephron endowment, and chronic kidney disease later in life. Currently, no early predictive biomarker exists for detecting altered kidney function in neonates with IUGR. Because nephrons produce key enzymes for the metabolism of arginine and methylarginine components, we quantified and compared the concentrations of arginine and methylarginine metabolites between IUGR and non-IUGR neonates to identify potential biomarkers for the early detection of altered kidney function in IUGR neonates. Seventy-one IUGR and 123 non IUGR neonates were examined. Serum and Urine samples were obtained between 30 h and 5 days of life and between 5 and 70 days of life. Serum concentrations of creatinine, urea, symmetric and asymmetric-dimethylarginine metabolites (SDGV, SDMA, ADGV, and ADMA), guanidino-2-oxo-caproic acid (GOCA), citrulline, homocitrulline, arginine, and homoarginine were quantified using LC-MS/MS and standard clinical laboratory methods. Datasets were compared by Mann-Whitney--Wilcoxon or Chi-square tests for continuous and discrete parameters. P values were corrected for multiple comparisons using the Bonferroni method. After Bonferroni correction, we found that serum creatinine, urea, SDGV, ADGV, and GOCA levels were significantly lower in neonates with IUGR. Consequently, the ratios of SDGV/SDMA, ADGV/ADMA, and GOCA/homoarginine were significantly lower in IUGR neonates. Our study suggests that arginine and methylarginine are possible early biomarkers for detecting altered kidney function in IUGR neonates.