Dimensionally stable anode (Doped-MMO) mediated electro-oxidation and multi-response optimization study for remediation of urea wastewater

In the present study, the potential application of novel doped-MMO (Ti/IrO₂/Ta₂O₅/SnO₂-Sb₂O₄) anodes as an alternative source to costly electrodes have been visualized for the EO treatment of urea. Parametric optimization for the treatment of urea through the EO process by doped-MMO has been done successfully. The high R² values of both responses i.e. % Degradation and energy consumption for quadratic suggested by BBD under RSM advocates a good correlation between predicted and experimental data. The maximum % Degradation and energy consumption at optimized were found to be 91.2%, 51.53 kWh m^-3 for urea respectively. Additionally, efforts were made to minimize treatment time further by implementing a dual effect, namely photo-electrocatalysis. The anode was found to be relatively stable even after 120 runs. The analysis of treated urea solution was verified in terms of total organic carbon (TOC) 90.0% reduction. The average operating cost of the electro-oxidation treatment process is determined to be 1.91 $ m^-3. The results of this study demonstrate the potential of doped-MMO as a promising concept for the treatment of wastewater that can be successfully applied in real life.

Discovery of novel IDO1 inhibitors targeting the protein's apo form through scaffold hopping from holo-IDO1 inhibitor

Immunomodulating enzyme IDO1 plays an important role in tumor immune resistance. Inhibiting IDO1 by small molecules with new mechanism of action is a potential strategy in IDO1 inhibitor development. Based on our urea derived compound originally binding with holo-IDO1, through scaffold hopping, a series of diisobutylaminophenyl hydroxyamidine compounds were designed. Unexpectedly, this novel class of IDO1 inhibitor does not target the holo form of IDO1 protein but displaces heme and binds to its apo form. Representative compound I-4 exhibits moderate potency with IC₅₀ value of 0.44 μM in cell-based IDO1 assay, which has the potential to be developed for IDO1-related cancer treatment.

Potentiometric urea biosensors

Excess nitrogen in the body is converted to urea in the liver, and urea is disposed as a waste product in urine. Urea concentration can change in body fluids such as blood due to the presence of certain disorders. Therefore, the determination of urea is of high importance in various areas including medical diagnosis, as well as food quality control and environmental monitoring. Potentiometric sensors have certain advantages over their alternatives, such as rapidity, portability, cost effectiveness, high sensitivity, easy operation and simple apparatus. Potentiometric urea biosensors based on enzyme urease have been developed using various materials including nanoparticles and films, and also using different methodologies. In this review, we covered potentiometric urea biosensors reported in the literature, and touched upon their certain structure characteristics and performance parameters including detection limit, working concentration range, response time and lifetime, all of which are of practical importance. Each potentiometric urea biosensor has its own advantages and drawbacks, thus the selection of appropriate method depends on the sample to be analyzed, its urea concentration range and other requirements of the particular application. Further research is needed in order to optimize the performance of these devices and to broaden their applicability.

Liming improves the stability of soil microbial community structures against the application of digestate made from dairy wastes

Lime is used to reduce soil acidification in agricultural soils. However, its effects on the soil microbial community are not well understood. Additionally, the soil microbial community is known to be influenced by fertilizers. However, the question remains whether liming influences the magnitude of fertilizers' impact on soil microbial communities. Therefore, an incubation experiment was performed to understand the effect of lime application (pH = 6.5 and 5.5 for the soils with and without lime, respectively) and fertilizer (digestate, urea and control) on the soil microbial community structures, stability and gene functions. Soils were sampled weekly after the application of fertilizers for a month. For microbial community analysis, DNA was extracted and sequenced targeting 16 S rRNA region. For gene abundances i.e 16 S rRNA, ammonia oxidizing archaea (AOA), ammonia oxidizing bacteria (AOB), nitrous oxide reductase (nosZ) and nitrite reductase (nirS) quantitative PCR was conducted. In results, the relative abundance of Actinobacteria was influenced more strongly by digestate in lime soils, while Alphaproteobacteria was influenced more strongly by digestate in the no lime soil. In NL treatments, digestate had a significant effect on more operational taxonomic units (146) compared to lime (127), indicating that lime application increased soil microbial community's stability. Liming and fertilizer had a significant effect on 16 S rRNA gene copy numbers with the highest values observed in lime plus digestate treatments. Soil pH had a significant effect on AOA, nosZ and nirS gene copy numbers with the highest values observed in lime treatments. In the lime treatments digestate application had a positive impact on AOB gene copy numbers but this was not the case for soils without liming treatments. These results indicate that soil pH and fertilizer type should be taken into consideration for the management of functional gene abundance in agricultural soils.

Urea-thiazole/benzothiazole hybrids with a triazole linker: synthesis, antimicrobial potential, pharmacokinetic profile and in silico mechanistic studies

Some urea-thiazole/benzothiazole hybrids with a triazole linker were synthesized via Cu(I)-catalysed click reaction. After successfully analysed by various spectral techniques including FTIR, NMR and HRMS, antimicrobial screening of the synthesized hybrids along with their precursors was carried out against two Gram (+) bacteria (Staphylococcus aureus and Bacillus endophyticus), two Gram (-) bacteria (Escherichia coli and Pseudomonas fluorescens) and two fungi (Candida albicans and Rhizopus oryzae). All the synthesized compounds (4a-4l) displayed better biological response than the standard fluconazole against both of the tested fungi. Compounds 4h and 4j were found to be the most active compounds against R. oryzae and C. albicans, respectively. Molecular docking of hybrid 4j and its alkyne precursor 1b in the active site of C. albicans target sterol 14-α demethylase was also performed and was also supported by molecular dynamics studies. In silico ADME prediction of synthesized urea-thiazole/benzothiazole hybrids with a triazole linker and their alkyne precursors was also predicted.

A Biomimetic Combination of Actives Enhances Skin Hydration and Barrier Function via Modulation of Gene Expression: Results of Two Double-Blind, Vehicle-Controlled Clinical Studies

INTRODUCTION

Xerosis cutis is characterized by a decreased stratum corneum (SC) hydration and an impaired skin barrier function. Urea, the most prevalent natural moisturizing factor (NMF), is currently considered the gold standard. Its efficacy can further be increased by combining urea with other NMF and skin barrier lipids (SBLs).

OBJECTIVE

We set out to evaluate physiological effects of a novel functional moisturizer containing 10% urea, additional NMF components, and a combination of SBLs on skin hydration and skin barrier integrity on a cellular and phenotypic level in female volunteers suffering from xerosis.

METHODS

Two double-blind, vehicle-controlled clinical studies were conducted. In the first study, 44 female subjects having very dry body skin applied the moisturizer or its vehicle twice daily to their volar forearms. Twenty-four hours after a single product application as well as 24 h after 2 weeks of treatment, SC hydration was measured by corneometry. Skin barrier function was assessed by transepidermal water loss 24 h and 48 h after 2 weeks of regular use. Twenty-four hours after 2 weeks of application, skin tape stripping was performed, and urea content was determined in the 3rd strip by means of high-performance liquid chromatography/tandem mass spectrometry. In the second study, 22 women with self-reported very dry skin applied the moisturizer or vehicle twice daily to their volar forearms for 2 weeks. Then, suction blister samples were obtained for gene expression analysis using RT-PCR.

RESULTS

Application of the actives led to significantly improved skin hydration and barrier function at all points in time. Compared to the vehicle, application of the moisturizer for 2 weeks resulted in a significant increase in SC urea content. Relative gene expression data revealed significant upregulation of genes associated with skin barrier function, hydration, differentiation, and lipid metabolism compared to the vehicle-treated area.

CONCLUSIONS

Overall, our data demonstrate that the functional moisturizer provides an adequate bioavailability of urea and a beneficial biophysical impact on xerotic skin. Topical treatment with a combination of urea and additional NMF as well as SBL can modify mRNA expression of important epidermal genes stimulating cellular processes and functions. The well-tolerated novel functional moisturizer stimulates molecular mechanisms involved in skin hydration and barrier function and is a profoundly effective treatment option for xerosis cutis.

Establishment of dry chemistry based reference intervals of renal function test parameters for the adult population of Kaski District, Nepal

Background

Reference intervals (RIs) for clinical chemistry test parameters are specific to the method of measurement and population under service. However, there has been no locally available dry chemistry based RIs for the Nepalese population. Thus, the present study aimed to establish dry chemistry based RIs for sodium, potassium, urea, and creatinine specific to adult populations of Kaski districts, Nepal

Methods

This was a cross-sectional study conducted at the Manipal Teaching Hospital, Pokhara, Kaski, Nepal on 360 healthy adult participants aged 18–65 years. The test parameters under study were analyzed using a fully automated OCD Vitros 350 dry chemistry analyzer following the protocols provided by the reagent kit manufacturer. The RIs were estimated using reference limits at 2.5th and 97.5th percentiles. The normal distribution of the data was tested by Kolmogorov–Smirnov, and Shapiro–Wilk tests. The differences between males and females RIs were compared by the Mann-Whitney test while age-specific RIs for each sex was compared by One-Way-ANOVA and Dunnett’s Multiple Comparisons Tests. All the data were managed and analyzed using MS Excel and SPSS version 20.

Results

The RIs of urea, creatinine, sodium, and potassium specific to the adult population of Kaski district, Nepal are as follows: urea: 4.20–13.70 mmol/L (males: 4.70–13.99; females: 4.20–13.23); creatinine: 44.20–106.10 μmol/L (males: 48.82–106.10; females: 35.40–83.78); sodium 135–146 mmol/L (males: 135–146; females: 135–146) and potassium 3.60–5.10 mmol/L (males: 3.54–5.0; females: 3.60–5.10). These RIs were found to be different from currently used RIs provided by the reagent manufacturer. RIs of all the test parameters were significantly influenced by the age of the study participants. However, only the RIs of urea, creatinine, and potassium were significantly influenced by sex.

Conclusions

The present study has for the first time established dry chemistry based RIs for selected renal function test parameters specific to the adult population of Kaski district, Nepal. This result will aid the clinician in minimizing the errors in result interpretation and making a precise clinical decision.

Supraphysiological concentration of urea affects the functional competence of Holstein-Friesian (Bos taurus) sperm

To understand the effects of urea on sperm functional attributes, fresh bull semen (n = 12) was subjected to four different concentrations (mg/mL) of urea to mimic the physiological (0.04 and 0.13), supraphysiological (0.43) concentrations and control (0 mg/mL). Sperm membrane integrity, kinematics, chromatin integrity, and mitochondrial membrane potential were assessed at different time points (before incubation, 0, 1, 2, and 4 h) of incubation. The concentration of urea in serum and seminal plasma was estimated and correlated with the ejaculate rejection rate and sperm functional attributes. The relative expression of urea transporter gene transcripts (UT-A and UT-B) was assessed in sperm and testis (control) using real-time PCR. The supraphysiological concentration of urea affected sperm kinematics, viability, functional membrane integrity, and acrosome integrity within 1 h of incubation (p < 0.05). Sperm head area decreased (p < 0.05) at 0 h and subsequently increased at 1 h of incubation in all media except supraphysiological (0.43 mg/dL) concentration of urea. Seminal plasma urea concentration showed a significant negative correlation with sperm motility, membrane integrity, and mitochondrial membrane potential (p < 0.05), but had a positive correlation with the ejaculate rejection rate (r = 0.69). Relative expression of the urea transporter genes revealed that UT-A was expressed only in the testis. In contrast, UT-B was expressed in both the testis and sperm, suggesting UT-B's role in regulating urea transport in sperm. At a supraphysiological level, urea adversely affected sperm functional attributes, osmoadaptation and may affect fertility.

Urea in Dermatology: A Review of its Emollient, Moisturizing, Keratolytic, Skin Barrier Enhancing and Antimicrobial Properties

Urea is a hygroscopic molecule (capable of absorbing water) present in the epidermis as a component of the natural moisturizing factor (NMF) and is essential for the adequate hydration and integrity of the stratum corneum. Urea improves skin barrier function including antimicrobial defense by regulating gene expression in keratinocytes relevant for their differentiation and antimicrobial peptide production. It also plays a fundamental role in regulating keratinocyte proliferation. One of the first uses of urea in modern medicine was the topical treatment of wounds due to its proteolytic and antibacterial properties. At present, urea is widely used in dermatology to improve skin barrier function and as one of the most common moisturizers and keratolytic agents. Urea-containing formulations are available in diverse formulations and concentrations. Multiple clinical trials on the use of urea-containing formulations have shown significant clinical improvement in many of the dermatosis presenting with scaly and dry skin such as atopic dermatitis, ichthyosis, xerosis, seborrheic dermatitis and psoriasis, among others. Furthermore, urea can increase skin penetration and optimize the action of topical drugs. Urea-based products are well tolerated; their side effects are mild and are more frequent at high concentration. Here, we present a review of the use of urea in dermatology, discussing its mechanism of action, safety profile and frequent indications.

Effect of urea on chlorinated aromatics formation mediated by copper and iron species in combustion flue gas

Urea ((NH₂)₂CO) is widely applied to the reduction of NO_X in modern full-scale solid waste incineration systems, but there is a lack of knowledge about how urea affects the formation and emission of Cl-aromatics. In this study, we investigated the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated polychlorinated naphthalenes (PCNs) via electrophilic chlorination and precursor pathway mediated by model fly ashes containing Cu and Fe species with or without urea addition. The results indicated that the addition of urea promoted the direct chlorination of parent aromatics over Cu (Ⅱ) chlorides and the coupling reaction of chlorophenols over Fe species, while suppressed the catalytic chlorination of parent aromatics over Fe (Ⅲ) chlorides and the coupling reaction of chlorophenols over Cu species. The diverse effects should be mainly attributed to the formation of complex salts containing NH₃ and NH₄⁺. The formation of complex salts of Fe chlorides and NH₄Cl could hinder the oxidization of Fe chlorides, and thus maintain the high activity of Fe species for catalyzing the coupling reaction of chlorophenols. The formation of complex salts of Cu (Ⅱ) chloride and NH₃ could prevent the chemical sorption of phenoxyl groups, and thus suppress the coupling reaction of chlorophenols. NH₃ released from the thermal decomposition of urea could not only react with Cl₂ to suppress the catalytic chlorination of aromatics, but also neutralize HCl to accelerate the direct chlorination of aromatics. In general, urea should act as inhibitor for suppressing the formation of Cl-aromatics in solid waste incineration systems.

Effects of thermal treatments on characteristics and morphological variations in the deposits of urea-SCR systems

Selective catalytic reduction (SCR) systems are employed by automobile manufacturers for the abatement of environmental pollutants like oxides of nitrogen (NO_x) emitted from exhaust gases of diesel engines. In SCR, the urea-water solution (UWS) is injected to exhaust gases in the form of a spray to generate the reducing agent NH₃. Deposit formation at lower temperatures is a major concern with this technology. The deposits not only create backpressure but also leak NH₃ to the environment as they deplete. It is very important to know the depletion characteristics of deposits formed at lower temperatures in order to assess the NH₃ leakage to the environment when the engine exhaust gases attain higher temperatures. In the present work, deposits formed at a low-temperature range of 150-200°C for continuous run along with UWS injection were investigated. Additionally, they were aged at 300°C in the absence of UWS to check the variation in characteristics with the rise of temperature. By gravimetric analysis, it is inferred that the deposits formed at higher pre-age temperatures are less prone to depletion as the temperature increases. The elemental analysis using energy-dispersive X-ray spectroscopy (EDX) indicates slight variation in carbon, nitrogen and oxygen compositions for all the pre-age conditions. As an extended study, the byproducts at pre-age and post-age conditions were investigated through X-ray diffraction (XRD). The compounds like cyanuric acid (CYA) and biuret were not observed when pre-age samples were aged at 300°C. Instead, the compounds like ammelide, ammeline, triuret and melamine were observed. Scanning electron microscope (SEM) study revealed morphological changes in both pre-age and post-age samples. Further, the crystallinity variations were also observed for the changes in the heating cycles during deposit formation. The gravimetric analysis of deposits in pre-age and post-age conditions helps in predicting the amount of deposits for transient load cycles.

Low Creatininuria due to Hyponatremia Is Reversible in Many Patients

BACKGROUND

Chronic hyponatremia has been reported to be associated with low solute intake and low creatinine excretion (reflecting likely sarcopenia). We wanted to study the effect, on the long term, of correction of hyponatremia on solute and creatinine excretion in chronic SIADH.

METHODS

We made a retrospective review of clinical and biochemical data of patients with euvolemic hyponatremia. We analyzed 24-h urine solute and creatinine excretion in volunteers with hyponatremia induced by dDAVP over 4 days, in 12 patients with chronic SIADH (>1 month) before and after a few days of SNa correction and in 12 patients (6 women and 6 men) before and after 3 months of SNa correction by a vaptan or urea.

RESULTS

We confirm a low urine creatinine and solute excretion only in patients with chronic hyponatremia (>1 month). Correction of SNa (from 127 ± 2.3 mEq/L to 139 ± 2.8 mEq/L) for >3 months, in the 12 patients (mean age 58 ± 18), was associated with an increase in 24-h creatinine excretion (from 986 ± 239 to 1,238 ± 220 mg; p < 0.02) and in patients treated with a vaptan (n = 5) solute excretion increased from 656 ± 207 mmol/24 h to 960 ± 193 mmol/24 h (p < 0.02). Sodium excretion increased also in the 12 patients (from 100 ± 53 mEq/24 h to 169 ± 38 mEq/24 h; p < 0.01).

CONCLUSION

Chronic hyponatremia (>1 month) is associated with a decrease in solute output (or intake) and in creatinine excretion. In many patients, these abnormalities are reversible in the long term.

Design, synthesis and anti-fibrosis evaluation of imidazo[1,2-a]pyridine derivatives as potent ATX inhibitors

A series of imidazo[1,2-a]pyridine compounds bearing urea moiety (8-27) were designed, synthesized and evaluated for their ATX inhibitory activities in vitro by FS-3 based enzymatic assay. Delightfully, benzylamine derivatives (14-27) exhibited higher ATX inhibitory potency with IC₅₀ value ranging from 1.72 to 497 nM superior to benzamide analogues (8-13). Remarkably, benzylamine derivative 20 bearing 4-hydroxypiperidine exerted an amazing inhibitory activity (IC₅₀ = 1.72 nM) which exceeded the positive control GLPG1690 (IC₅₀ = 2.90 nM). Simultaneously, the binding model of 20 with ATX was established which rationalized the well performance of 20 in enzymatic assay. Accordingly, further in vivo studies were carried out to evaluate direct anti-fibrotic effects of 20 through Masson staining. Notably, 20 effectively alleviated lung structural damage with fewer fibrotic lesions at an oral dose of 60 mg/kg, qualifying 20 as a promising ATX inhibitor for IPF treatment.

New carbon nitride close to C6N7 with superior visible light absorption for highly efficient photocatalysis

The rational design and construction of novel two-dimensional (2D) carbon nitrides (CNs) beyond g-C₃N₄ is a hot topic in the fields of chemistry and materials. Inspired by the polymerisation of urea, we have prepared a series of novel C-C bridged heptazine CNs UO_x (where x is the ratio of urea to oxamide, x = 1, 1.5, 2, 2.5, and 3), which are similar to (C₆N₇)_n, upon the introduction of oxamide. As predicted using density functional theory (DFT) calculations, the conjugated structure of UO_x was effectively extended from an individual heptazine to the entire material. Consequently, its bandgap was reduced to 2.05 eV, and its absorption band edge was significantly extended to 600 nm. Furthermore, its carrier transfer and separation were significantly enhanced, establishing its superior photocatalytic activity. The optimised UO₂ exhibits a superior photocatalytic hydrogen production rate about 108.59 μmol h^-1 (using 10 mg of catalyst) with an apparent quantum efficiency (AQE) of 36.12% and 0.33% at 420 and 600 nm, respectively, which is one of the most active novel CNs reported to date. Moreover, UO₂ exhibits excellent photocatalytic activity toward the oxidation of diphenylhydrazine to azobenzene with conversion and selectivity reaching ~100%, which represents a promising highly efficient 2D CN material. Regarding phenols degradation, UO₂ also displayed significantly higher activity and durability during the degradation of phenol when compared to traditional g-C₃N₄, highlighting its significant potential for application in energy, environment and photocatalytic organic reactions.

A Randomized Double-Blind Parallel-Group Study to Evaluate the Long-Term Effects of a Medical Device Containing 0.3% Octatrienoic Acid in the Treatment of Grade III Actinic Keratosis

INTRODUCTION

Actinic keratosis (AK) consists of skin lesions with a milder degree of keratinocytic atypia. It can be also referred to as "field of cancerization," which can potentially evolve to cutaneous squamous cell carcinoma (SCC). Several therapeutic options are currently available, but not all are indicated on hyperkeratotic lesions. This study aimed to test the efficacy and tolerability of a medical device containing 2,4,6-octatrienoic acid and urea for the treatment of hyperkeratotic AK lesions.

METHODS

Seventy male and female subjects with grade III AK were enrolled in this randomized double-blind parallel-group study. The product was applied once daily for three consecutive months. The primary efficacy endpoint was the reduction in the mean number of AK lesions per subject from baseline (T0) to the end of the trial (T1) and 3 months after the end of the treatment period (T2). Therefore, clearance of target AK lesions at the end of the treatment period and local skin reaction score (LSR) versus baseline were evaluated.

RESULTS

There was a decrease of mean values from baseline to visit T2 in both treatment groups, but the decrease (versus baseline values) was more evident in the Kerà K2 group than in the placebo group (-42.78, SD 26.53, versus -6.20, SD 31.57), and the difference was statistically significant (p < 0.001). For 70 subjects (56.7%) in the Kerà K2 group and 3 (11.54%) in the placebo group, a significant (p < 0.005) partial clearance was evidenced. The product was well tolerated, and no serious adverse events were reported during the duration of the trial. Subject self-assessment of acceptability, local tolerability, and the cosmetic result was good at both T1 and T2 for both groups.

CONCLUSIONS

The medical device has demonstrated good efficacy in the reduction of visible AKs, encouraging its use.

Selective recovery of phosphorus and urea from fresh human urine using a liquid membrane chamber integrated flow-electrode electrochemical system

Phosphorus (P) extraction from human urine is a potential strategy to address global resource shortage, but few approaches are able to obtain high-quality liquid P products. In this study, we introduced an innovative flow-electrode capacitive deionization (FCDI) system, also called ion-capture electrochemical system (ICES), for selectively extracting P and N (i.e., urea) from fresh human urine simply by integrating a liquid membrane chamber (LMC) using a pair of anion exchange membrane (AEM). In the charging process, negatively charged P ions (i.e., HPO₄^2- and H₂PO₄^-) can be captured by acidic extraction solutions (e.g., solutions of HCl, HNO₃ and H₂SO₄) on their way to the anode chamber, leading to the conversion of P ions to uncharged H₃PO₄, while other undesired ions such as Cl^- and SO₄^2- are expelled. Simultaneously, uncharged urea molecules remain in the urine effluent with the removal of salt. Thus, high-purity phosphoric acid and urea solutions can be obtained in the LMC and spacer chambers, respectively. The purification of P in an acidic environment is ascribed largely to the competitive migration and protonation of ions. The latter contributes ~27% for the selective capture of P. Under the optimal operating conditions (i.e., ratio of the urine volume to the HCl volume = 7:3, initial pH of the extraction solution = 1.43, current density = 20 A/m² and threshold pH ~ 2.0), satisfactory recovery performance (811 mg/L P with 73.85% purity and 8.3 g/L urea-N with 81.4% extraction efficiency) and desalination efficiency (91.1%) were obtained after 37.5 h of continuous operation. Our results reveal a promising strategy for improving in selective separation and continuous operation via adjustments to the cell configuration, initiating a new research dimension toward selective ion separation and high-quality P recovery.

Biotin and Zn2+ Increase Xylitol Production by Candida tropicalis

In this study, the medium requirements to increase the production of xylitol by using Candida tropicalis (CT) have been investigated. The technique of single addition or omission of medium components was applied to determine the nutritional requirements. The addition of amino acids such as Asp, Glu, Gln, Asn, Thr, and Gly had no significant effect on CT growth. However, in the absence of other metal ions, there was a higher concentration of cell growth and xylitol production when only Zn2+ was present in the medium. The analysis of various vitamins unveiled that biotin and thiamine were the only vitamins required for the growth of CT. Surprisingly, when only biotin was present in the medium as a vitamin, there was less growth of CT than when the medium was complete, but the amount of xylitol released was significantly higher. Overall, this study will increase the xylitol production using the single omission or addtion technique.

Development of a defined medium for Corynebacterium glutamicum using urea as nitrogen source

Corynebacterium glutamicum has been widely used for bulk and fine chemicals fermentation these years. In this study, we developed a defined medium for this bacteria based on the widely used CGXII minimal medium. We evaluated the effects of different components in CGXII on cell growth of C. glutamicum ATCC 13032 and improved the medium through single-factor experiment and central composite design (CCD). Urea, K₂HPO₄ and MgSO₄ were found to be significant factors. 7 out of the total 15 components were modified. (NH₄)₂SO₄, KH₂PO₄, and protocatechuic acid were eliminated. Amounts of urea and MgSO₄ were increased, and concentrations of biotin and glucose were reduced. The resulting R2 medium was proved to be more suitable for cell growth, plasmid amplification and protein production than the original recipe. Remarkably, cell biomass accumulation in R2 increased by 54.36% than CGXII. Transcriptome analysis revealed alteration of carbon metabolism, cation transport and energy synthesis, which might be beneficial for cell growth in R2. Considering the high nitrogen content and availability of urea, the new medium is simplified and cost effective, which holds attractive potential for future study.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02959-6.

A critical review on challenges and trend of ultrapure water production process

The recent and vigorous developments in semiconductor technology strictly request better quality and large quantity of ultrapure water (UPW) for their production. It is crucial to secure a large amount of raw water for the future development of UPW production. Using reclaimed water as alternative raw water source to produce UPW is therefore considered the feasible trend and solution for sustainable use of water resources towards a common future practice in UPW production. The challenge of using reclaimed water is due to its higher content of organic pollutants, especially small molecule organic pollutants such as urea, which are difficult to remove through traditional UPW production process. Consequently, improving the existing UPW production process to meet the water standard desired in the semiconductor industry is essential. This paper reviewed the current traditional processes for removing organic matters in UPW production, including ion-exchange (IX) adsorption, granular activated carbon (GAC) adsorption, reverse osmosis (RO) and ultraviolet (UV) irradiation. The potential problems in the actual UPW production process were identified when using reclaimed water as raw water source. A new strategy of applying the advanced oxidation process (AOPs) to UPW production as a supplementary unit to guarantee UPW quality was proposed. Its feasibility and research focus were then analyzed and discussed in obtaining a new solution for a future development of the UPW production process.

Spastic gait, intellectual disability and seizures due to a rare mutation causing hyperargininemia

Hyperargininemia is an autosomal recessive disorder caused by a defect in the arginase I enzyme. We present a case of a 20-year-old male with severe spastic gait, intellectual disability and seizures. Metabolic tests revealed high levels of arginine in blood serum. Hyperargininemia was attributed to a likely pathogenic rare mutation of ARG1 gene [Chr6: g131905002_131905002 G>A (p.Arg308Gln) homozygous] detected in Whole Exome Sequencing resulting in deficiency in arginase I enzyme. Following the diagnosis, the patient has been treated with low protein diet, aminoacid and vitamin supplements. The accumulation of arginine, may contribute to the pathogenesis of severe neurological manifestations, however, low protein intake diet may lead to a favorable outcome. Therefore, clinicians should screen for hyperargininemia in early childhood in case of strong clinical suspicion.

Recurrent Altered Mental State Associated with Nonhepatic Hyperammonemia Presented in an Elderly Female Patient: Probable Late-Onset Urea Cycle Disorder

Altered mentality associated with hyperammonemia is usually diagnosed in patients with liver disease. Nonhepatic hyperammonemia may be present in critically ill patients or may be caused by high protein diets or certain drugs. Urea cycle disorders (UCDs) rarely present with altered mentality with hyperammonemia in adult patients. An 82-year-old female visited our hospital with complaints of abnormal behavior and confusion. Routine blood tests revealed elevated serum ammonia. Her mentality and serum ammonia level normalized after lactulose enema and she was discharged thereafter. However, she was later re-admitted because of recurrent altered mentality. Amino acid analysis revealed that serum levels of ornithine and glutamine increased significantly, whereas the levels of alanine and glutamic acid increased slightly, and the levels of arginine, lysine, and citrulline were normal, which were probably caused by reduced activity of the mitochondrial ornithine carrier-1. Although our patient was not diagnosed genetically, this case illustrates the under-recognized fact that UCD can occur in a senile age. Clinical suspicion of UCDs in patients with hyperammonemia is critical for early diagnosis and to prevent the significant neurologic sequelae.

Extraction and Separation of Mycobacterial Proteins

The extraction and separation of native mycobacterial proteins remain necessary for antigen discovery, elucidation of enzymes to improve rational drug design, identification of physiologic mechanisms, use as reagents for diagnostics, and defining host immune responses. In this chapter, methods for the manipulation of whole mycobacterial cells and culture exudates are described in detail as these methods are the requisite first steps towards native protein isolation. Specifically, several methods for the inactivation of viable Mycobacterium tuberculosis along with qualification assays are provided, as this is key to safe manipulation of cell pastes for downstream processes. Next, the concentration of spent culture filtrate media in order to permit separation of soluble, secreted proteins is described followed by the separation of mycobacteria extracellular vesicles (MEV) from the remaining soluble proteins in spent media. We then describe the generation of whole-cell lysate and facile separation of lysate into subcellular fractions to afford cell wall, cell membrane, and cytosol-enriched proteins. Due to the hydrophobic nature of cell wall and cell membrane proteins, several extraction protocols to resolve protein subsets (such as extraction with urea and SDS) are also provided. Finally, methods for separation of hydrophobic and hydrophilic proteins from both whole-cell lysate and spent culture media are included. While these methods were optimized for the manipulation of Mycobacterium tuberculosis cells, they have been successfully applied to extract and isolate Mycobacterium leprae, Mycobacterium ulcerans, and Mycobacterium avium proteins.

High efficiency of osmotically stable laccase for biotransformation and micro-detoxification of levofloxacin in the urea-containing solution: Catalytic performance and mechanism

Laccase-catalyzed oxidation was applied in the biotransformation of levofloxacin (a potentially environmental antibiotic contamination); however, the enzyme may denature in urea-containing wastewater and lead to the formation of an inactive form followed by decreasing the yield of the bio-removal. In this study, the osmolytes-stabilized laccase was used to eliminate levofloxacin in the urea-containing solution. Sorbitol and proline 100 mM appeared to be the two most efficient laccase protectants against the urea-induced denaturation. In a 1-M urea solution, the maximum velocity (V_max) of laccase was estimated to be 39.1 μmol min^-1 mg^-1. This value was improved to 101.7 and 51.8 μmol min^-1 mg^-1 in the presence of sorbitol and proline, respectively. In optimal conditions for the elimination of levofloxacin, sorbitol- and proline-treated laccase led to 82.9 % and 76.2 % bio-removal of the applied fluoroquinolone in 1 M urea solution, respectively. Biotransformation products of the parent antibiotic were spectroscopically analyzed that assigned to different reaction pathways including demethylation, defluorination, decarboxylation, deamination, and hydroxylation. A micro-toxicity study concerning the growth of some Gram⁺ and Gram^- bacteria exhibited decreasing in inhibition of laccase-treated levofloxacin after a 10-h incubation at 37 °C.

Monitoring dialysis adequacy: history and current practice

Dialysis adequacy for pediatric patients has largely followed the trends in adult dialysis by judging the success or adequacy of peritoneal or hemodialysis with urea kinetic modeling. While this provides a starting point to establish a dose of dialysis, it is clear that urea is only part of the picture. Many clinical parameters and interventions now have been identified that are just as impactful on mortality and morbidly as urea clearance. As such, our concept of adequacy is evolving to include non-urea parameters and assessing the impact that following an "adequate therapy" has on patient lives. As we move to a new era, we consider the impact these therapies have on patients and how it affects the quality of their lives; we must take these factors into consideration to achieve a therapy that is not just adequate, but livable.

Smartphone-assisted point-of-care colorimetric biosensor for the detection of urea via pH-mediated AgNPs growth

Smartphone-assisted point-of-care (POC) bioassay has brought a giant leap in personal healthcare system and environmental monitoring advancements. In this study, we developed a rapid and reliable colorimetric urea biosensor assisted by a smartphone. We employed hydrolysis of urea into NH₃ by urease, which activates the reduction power of tannic acid, to generate silver nanoparticles for a dramatic colorimetric response. The proposed urea biosensor was validated in a solution to provide high selectivity against various interferents in human urine. It had high sensitivity, with a limit of detection as low as 0.0036 mM, and a high reliability of 99% ± 2.9% via the standard addition method. The urea biosensor was successfully implanted on a paper to facilitate smartphone-assisted POC readout with a limit of detection of 0.58 mM and wide detection range of 500 mM, whereby direct diagnosis of human urine without dilution was realized. Our smartphone-assisted POC colorimetric urea biosensor will pave the way for daily monitoring systems of renal and hepatic dysfunction diseases.

Slow release fertilizer prepared with lignin and poly(vinyl acetate) bioblend

Controlled or slow release fertilizers have been recommended to enhance crop yield, while minimizing environmental and economic issues related from current fertilizer applications. However, alternative biodegradable and non-toxic coating material should be suggested to produce biocoated fertilizers. Here we propose the use of lignin and poly(vinyl acetate) (PVAc) as biocoating materials for preparing slow release urea fertilizer. The blend of PVAc and lignin at a mass ratio of 75:25 improved the characteristics of the formed film and increased the nitrogen release time if compared to the pure polymers. The nitrogen release time from urea granules coated with a polymeric layer of 154.3 ± 5.5 μm formed by lignin and PVAc was 36 times greater than from bare urea. The increase in the polymeric coating from 52.6 ± 5.2 to 80.2 ± 6.1 μm decreased the curvature of the nitrogen release data by a factor of at least 1.7, while the curvature was decreased in at least 1.3 with the increase in the polymeric coating from 80.2 ± 6.1 to 158.9 ± 10.6 μm. The adjustment of nitrogen release data to the Peppas-Sahlin model indicated the Fickian diffusion is more predominant than relaxation contributions, since the used polymers did not present considerable swelling. Thus, the blending of PVAc and lignin at 25 wt% of lignin and 75 wt% of PVAc is suggested as a biocoating material for producing slow release fertilizers.

Automated liquid-liquid microextraction and determination of sulfonamides in urine samples based on Schiff bases formation in natural deep eutectic solvent media

In this work, an automated liquid-liquid microextraction procedure for the determination of sulfonamides (sulfamethoxazole, sulfamethazine and sulfapyridine) in urine samples using natural deep eutectic solvent is presented for the first time. The mechanism for extraction of sulfonamides was based on the formation of colored Schiff bases in the presence of vanillin, which acted as a derivatization reagent and precursor of natural deep eutectic solvent (an extractant). In this procedure, thymol was used as both media for Schiff bases formation and as a second precursor of the natural deep eutectic solvent. The formation of the Schiff bases was confirmed by mass spectrometry. A Lab-In-Syringe concept was applied for the automation of the microextraction procedure. The procedure involved mixing the sample and natural deep eutectic solvent into a syringe of a flow system, formation and microextraction of colored Schiff base followed by UV-Vis detection. Under optimal automated conditions the limits of detection, calculated from a blank test based on 3s (sigma) were 0.06, 0.1, and 0.06 mg L^-1 for sulfapyridine, sulfamethoxazole and sulfamethazine. The proposed automated procedure permitted the routine determination of one drug (sulfamethoxazole, sulfamethazine or sulfapyridine) in urine samples to be achieved in less than 10 min.

Construction of wood-based cellulose micro-framework composite form-stable multifunctional materials with thermal and electrical response via incorporating erythritol-urea (thiourea)-carbon nanotubes

In this study, two kinds of form-stable multifunctional materials with thermal and electrical response (FPCMs: DP-E7U3-CNT, DP-E7T3-CNT) are composed of wood-based honeycomb-like celluloses micro-framework (DP), carbon nanotubes (CNT), erythritol-urea (E7U3) or erythritol-thiourea (E7T3). In FPCMs, DP acts as a skeleton structure to seal E7U3 and E7T3 and provide more pathways for heat conduction. The CNT acts as an extended surface to further improve thermal conductivity. FE-SEM showed that the honeycomb-like pore structure of DP was completely filled with E7U3, E7T3 and CNT. FTIR and XRD analysis show that there is only a combination of physical interactions between the components of FPCMs. DSC curves and thermal conductivity analysis results show that DP-E7U3-1.5CNT and DP-E7T3-1.5CNT with the mass fraction of carbon nanotubes (1.5 wt%) have the highest latent heat values (230.3 J/g, 272.2 J/g) and thermal conductivity (0.9832 W/(m·K), 0.9363 W/(m·K)). Both DP-E7U3-1.5CNT and DP-E7T3-1.5CNT exhibit high latent heat retention and thermal stability after 100 heating-cooling cycles. In addition, DP-E7U3-1.5CNT and DP-E7T3-1.5CNT show excellent performance in light-heat energy conversion-storage, actual latent heat storage and release, thermal and electrical response performance, which make it has great potential to be multifunctional materials with thermal storage sand electrical response.

Design, synthesis and in vitro biological evaluation of a novel class of anti-adenovirus agents based on 3-amino-1,2-propanediol

Nowadays there is not an effective drug for the treatment of infections caused by human adenovirus (HAdV) which supposes a clinical challenge, especially for paediatric and immunosuppressed patients. Here, we describe the design, synthesis and biological evaluation as anti-adenovirus agents of a new library (57 compounds) of diester, monoester and triazole derivatives based on 3-amino-1,2-propanediol skeleton. Seven compounds (17, 20, 26, 34, 44, 60 and 66) were selected based on their high anti-HAdV activity at low micromolar concentration (IC₅₀ from 2.47 to 5.75 µM) and low cytotoxicity (CC₅₀ from 28.70 to >200 µM). In addition, our mechanistic assays revealed that compounds 20 and 44 might be targeting specifically the HAdV DNA replication process, and compound 66 would be targeting HAdV E1A mRNA transcription. For compounds 17, 20, 34 and 60, the mechanism of action seems to be associated with later steps after HAdV DNA replication.

Photolysis of N-chlorourea and its effect on urea removal in a combined pre-chlorination and UV254 process

Urea is one of the most important nitrogenous organic pollutants in water, and its removal attracts attention because of a growing concern related to water eutrophication. Urea has previously been considered to be largely unaffected by the UV-chlorine process. However, N-chlorourea, an intermediate of urea chlorination, has been shown to absorb ultraviolet radiation, and as such its photolysis is possible. Experiments were conducted to quantify the kinetics of N-chlorourea degradation under UV₂₅₄ irradiation. The results showed that about 92% of N-chlorourea was degraded under UV₂₅₄ irradiation. Ammonia and nitrate were detected as the primary nitrogen containing products of the photolysis of N-chlorourea. Solution pH ranging from 3.0 to 7.5 influenced the distribution of these products but not on the degradation rate. Based on these data, a possible pathway of photodegradation of N-chlorourea under UV₂₅₄ is proposed. The degradation of urea was also achieved by the photolysis of N-chlorourea during the combined pre-chlorination and UV₂₅₄ process. Insights gained in this study may be useful for exploring the potential of combined pre-chlorination and UV₂₅₄ process on urea removal in water treatment.

Caffeine decreases ammonemia in athletes using a ketogenic diet during prolonged exercise

OBJECTIVES

Both exercise and a ketogenic (low-carbohydrate) diet favor glycogen depletion and increase ammonemia, which can impair physical performance. Caffeine supplementation has been routinely used to improve exercise performance. Herein, the effect of xanthine was evaluated on ammonemia in cyclists who were placed on a ketogenic diet and engaged in prolonged exercise.

METHODS

Fourteen male cyclists followed a ketogenic diet for 2 d before and during the experimental trial. The cyclists were assigned to either the caffeine- (CEx; n = 7) or placebo-supplemented (LEx; n = 7) group. Blood samples were obtained during cycling and the recovery periods.

RESULTS

The CEx group showed a significant decrease (up to 25%) in blood ammonia at 60, 90, and 120 min after beginning exercise compared with the LEx group. A higher concentration of apparent blood urea was observed in the LEx group than in the CEx group at 60 to 90 min of exercise (~10%). In addition, a significant increase in blood glucose levels was evident at 30 min of exercise (~28%), and an increase in blood lactate levels was visible during the first 30 to 60 min of exercise (~80%) in the CEx group.

CONCLUSIONS

Our results suggest that the consumption of caffeine might attenuate the increase in ammonemia that occurs during exercise.

Synthesis of new hydrazone derivatives and evaluation of their monoamine oxidase inhibitory activity

A novel series of hydrazone derivatives were designed and synthesized. Their structures were characterized by IR, ¹H NMR, ¹³C NMR and HR-MS spectroscopic methods. The newly synthesized compounds were evaluated for their inhibitory activity against monoamine oxidase enzymes (MAO-A and MAO-B). Compounds 2a, 2k, 4a and 4i showed significant inhibitory activity against MAO-A, with IC₅₀ value in the range of 0.084-0.207 µM compared to reference drug moclobemide (IC₅₀ value = 6.061 µM). These compounds (2a, 2k, 4a and 4i) were exposed to cytotoxicity tests to establish their preliminary toxicological profiles and were found to be non-cytotoxic. Moreover, the most effective compound 4i was evaluated using enzyme kinetics and docking studies to elucidate the plausible mechanisms of inhibition of MAO-A. According to enzyme kinetic studies, compound 4i was a reversible and competitive inhibitor with similar inhibition features as the substrates. Also, it was seen that this compound was settled down very properly at the active site of MAO-A enzyme by doing important interactions owing to the docking studies. Finally, ADME predictions were applied to estimate pharmacokinetic profiles of synthesized compounds. According to calculated ADME predictions, all parameters of the compounds were within the standard ranges in terms of "Rule of Five" and "Rule of Three" and it was detected that the synthesized compounds (2a-4i) have good and promising pharmacokinetic profiles.

The role of energy, serine, glycine, and 1-carbon units in the cost of nitrogen excretion in mammals and birds

The efficiency with which dietary protein is used affects the nitrogen excretion by the animal and the environmental impact of animal production. Urea and uric acid are the main nitrogen excretion products resulting from amino acid catabolism in mammals and birds, respectively. Nitrogen excretion can be reduced by using low-protein diets supplemented with free amino acids to ensure that essential amino acids are not limiting performance. However, there are questions whether the capacity to synthesize certain nonessential amino acids is sufficient when low-protein diets are used. This includes glycine, which is used for uric acid synthesis. Nitrogen excretion not only implies a nitrogen and energy loss in the urine, but energy is also required to synthesize the excretion products. The objective of this study was to quantify the energy and metabolic requirements for nitrogen excretion products in the urine. The stoichiometry of reactions to synthesize urea, uric acid, allantoin, and creatinine was established using information from a publicly available database. The energy cost was at least 40.3, 60.7, 64.7, and 65.4 kJ/g excreted N for urea, uric acid, allantoin, and creatinine, respectively, of which 56, 56, 47, and 85% were retained in the excretion product. Data from a broiler study were used to carry out a flux balance analysis for nitrogen, serine, glycine, and so-called 1-carbon units. The flux balance indicated that the glycine intake was insufficient to cover the requirements for growth and uric acid excretion. The serine intake was also insufficient to cover the glycine deficiency, underlining the importance of the de novo synthesis of serine and glycine. One-carbon units are also a component of uric acid and can be synthesized from serine and glycine. There are indications that the de novo synthesis of 1-carbon units may be a "weak link" in metabolism, because of the stoichiometric dependency between the synthesized 1-carbon units and glycine. The capacity to catabolize excess 1-carbon units may be limited, especially in birds fed low-protein diets. Therefore, there may be an upper limit to the 1-carbon-to-glycine requirement ratio in relation to nutrients that supply 1-carbon units and glycine. The ratio can be reduced by increasing uric acid excretion (i.e., reducing protein deposition) or by dietary supplementation with glycine. The hypothesis that the 1-carbon-to-glycine requirement ratio should be lower than the supply ratio provides a plausible explanation for the growth reduction in low-protein diets and the positive response to the dietary glycine supply.

Influence of creams with different urea concentrations on plantar skin hydration

INTRODUCTION

The skin is the body's outermost organ, and one of its main functions is to provide protection against potential infections. Hydration is related to the proper functioning of the skin, hindering the appearance of wounds or cracks which could lead to the occurrence of infections or other dermatological alterations. The skin of the foot is thicker than that of the rest of the body due to the load it supports, and it is more complicated to maintain. The intention of this study was to evaluate the efficacy of different concentrations of urea (5% and 20%) in hydrating the foot compared to a placebo cream.

METHODS

The study was carried out with 60 subjects of ages from 20 to 35 years in age. The experimental protocol was initiated by creating three randomized groups (1:1:1), each being treated with a different cream: placebo, 5% urea cream, and 20% urea cream. The examination was carried out using a non-invasive instrument (Corneometer CM 825®) that detects the skin surface hydration.

RESULTS

Analysis of the hydration of the different study zones according to the cream used showed no significant differences between the placebo and 5% urea for the first MTH and heel, but a significant difference for the fifth MTH. There were significant differences in all study areas between the placebo and 20% urea creams, but none between the 5% urea and 20% DISCUSSION/CONCLUSION: The conclusion drawn was that skin hydration was greater with the 20% urea cream versus the placebo, but there were no differences found when comparing either the 20% and 5% urea creams or the placebo and 5% urea creams.

p-Dimethylaminobenzaldehyde-based chemosensor for on-site sensing of ammonia precursor in concrete

A chemosensor for on-site sensing of ammonia precursor in concrete to avoid a problem of ammonia emission into the indoor space of concrete buildings was designed and implemented. It was found that aqueous extracts of concrete samples containing antifreeze additives and excreting ammonia were colored in the presence of p-dimethylaminobenzaldehyde. This phenomenon was used for the fast visual sensing of main ammonia precursor (urea) in concrete for the first time. The developed sensor consisted of a sensing solid phase based on an adsorbent modified with p-dimethylaminobenzaldehyde. Various adsorbents were investigated for the immobilization of the reagent and it was established that silica adsorbent Silochrom C-120 provided effective retention of the reagent and Schiff's base formation during the sampling. Moreover, Silochrom C-120 modified with ascorbic acid was proposed to eliminate the oxidant interference. The sensor displayed excellent selectivity and sensitivity with the visual detection limit of 15 mg kg^-1 in terms of urea. The chemosensor was successfully applied by builders on different construction sites. Sample preparation and sensing times were about 2 min and 1 min, respectively.

Enhanced protein and amino acids of corn-ethanol co-product by Mucor indicus and Rhizopus oryzae

Upcycle of co-products from corn-ethanol plant into protein-rich animal feed with balanced key amino acids via solid-state fermentation is a promising approach to economically support both biofuel and animal feed industries. However, there are multiple types of solid-state fermentation microorganisms and growth conditions that have not been tested. In this study, Mucor indicus and Rhizopus oryzae were used to ferment corn-based wet distiller's grains with solubles (WDGS). The effects of fermentation conditions (temperature, agitation, and moisture) and supplementations (extraneous carbon and nitrogen sources) were evaluated on protein production and amino acids profiles before and after fermentation. The study established best fermentation conditions (23 °C, static incubation for 4 days at 70% initial moisture content) to improve protein content for both R. oryzae and M. indicus. Moreover, urea supplied to R. oryzae and M. indicus improved protein concentration by 35 and 38%, and total amino acids content by 28 and 18%, respectively. The amount of 693.1 and 451.8 mg of additional total amino acids including 262.8 and 227.7 mg of key amino acids (lysine, methionine, tryptophan, and arginine) was synthesized by R. oryzae and M. indicus, respectively, per supply of 536 mg urea in 25 g of WDGS. This study demonstrated the feasibility of urea as a low-cost nitrogen source for amino acid biosynthesis in fungal fermentation of WDGS, which could contribute to the increasing demand for high-value monogastric animal feed.

Equipment-free quantitative determination of urea based on paper-based sensor via urease-mediated chitosan viscosity change

In this study, a paper-based sensor combined with visual distance-readout technique for point of-care testing (POCT) of urea was developed by urease-mediated chitosan viscosity change. A series of factors that affect the performance of the sensor were investigated, including the type of filter paper, chitosan concentration, acetic acid concentration and enzymatic reaction conditions. Under optimal conditions, the proposed method for urea determination has good linearity between 3.8-15.1 mM. The limit of quantitation is 3.8 mM. Finally, the paper-based sensor was successfully applied to the determination of urea in two diesel exhaust fluid (DEF) samples. The recoveries of urea were 91.4 % and 109.9 % in DEF-1 and DEF-2, respectively. The present study provides a novel approach, which integrates paper-based sensor and visual distance-readout technique, for monitoring urea in POCT application, especially in remote or resource-limited regions.

Comparisons of urea or ammonium on growth and fermentative metabolism of Saccharomyces cerevisiae in ethanol fermentation

This work was mainly about the understanding of how urea and ammonium affect growth, glucose consumption and ethanol production of S. cerevisiae, in particular regarding the basic physiology of cell. The basic physiology of cell included intracellular pH, ATP, NADH and enzyme activity. Results showed that fermentation time was reduced by 19% when using urea compared with ammonium. The maximal ethanol production rate using urea was 1.14 g/L/h, increasing 30% comparing with the medium prepared with ammonium. Moreover, urea could decrease the synthesis of glycerol from glucose by 26% comparing with ammonium. The by-product of acetic acid yields decreased from 40 mmol/mol of glucose (with urea) to 24 mmol/mol of glucose (with ammonium). At the end of ethanol fermentation, cell number and pH were greater with urea than ammonium. Comparing with urea, ammonium decreased the intracellular pH by 14% (from 7.1 to 6.1). Urease converting urea into ammonia resulted in a more than 50% lower of ATP when comparing with ammonium. The values of NADH/DCW were 0.21 mg/g and 0.14 mg/g respectively with urea and ammonium, suggesting a 33% lower NADH. The enzyme activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was 0.0225 and 0.0275 U/mg protein respectively with urea and ammonium, which was consistent with the yields of glycerol.

2D Co3O4 stabilizing Rh nano composites developed for visual sensing bioactive urea and toxic p-aminophenol in practice by synergetic-reinforcing oxidase activity

To enlarge the perspective of nanozyme, 2-dimensional Co₃O₄ stabilizing Rh nano composite (2D Co₃O₄@Rh NC) was identified and developed first by one-pot surfactant-aided oxido-reduction. By virtue of the synergetic-reinforcing oxidase activity between 2D Co₃O₄ substrate and Rh nano particles, the obtained 2D Co₃O₄@Rh NC could catalyze the oxidation of chromogenic substrate 3,3',5,5,'-tetramethylbenzidine (TMB) to blue oxTMB with quite a low Michaelis-Menten constant (K_m) of 0.018 mM and a quick v_max of 6.45 × 10^-8 M s^-1, expressing superior oxidase-like catalysis with a wide temperature range from 20 to 60 °C. Importantly, either bioactive urea or toxic p-aminophenol (p-Ap) could exclusively alter the existed state of oxTMB with differentiable color changes. Under the optimized conditions, 2D Co₃O₄@Rh NC was successfully applied for ratiometric colorimetric sensing urea and p-Ap in environmental water, soil and urine samples with low detection limits (1.1 μM for urea and 0.68 μM for p-Ap) and satisfactory recoveries (96.0-105.8%). The synergetic enhanced oxidase-like activity of 2D Co₃O₄@Rh NC and the different reaction mechanisms of the 2D Co₃O₄@Rh NC-TMB system to urea and p-Ap were investigated. Not only does the work provide an efficient way for sensing organic pollution of p-Ap, it will offer an efficient potential for diagnosing urea-related diseases on clinical medical testing in future.

Identification of a new class of HBV capsid assembly modulator

The HBV core protein is a druggable target of interest due to the multiple essential functions in the HBV life cycle to enable chronic HBV infection. The core protein oligomerizes to form the viral capsid, and modulation of the HBV capsid assembly has shown efficacy in clinical trials. Herein is described the identification and hit to lead SAR of a novel series of pyrazolo piperidine HBV capsid assembly modulators.

Hepatic and renal damage by alcohol and cigarette smoking in rats

Chronic use of alcohol and tobacco cigarettes is associated to millions of deaths per year, either by direct or indirect causes. However, few studies have explored the additional risks of the combined use of these drugs. Here we assessed the effect of the combined use of alcohol and cigarette smoke on liver or kidney morphology, and on biochemical parameters in chronically treated rats. Male Wistar rats were allocated to receive 2 g/kg alcohol orally, which was followed by the inhalation of smoke from six cigarettes during 2 h (ALTB group) for 28 days. Other groups received alcohol alone (AL) or were exposed to cigarette smoke (TB) alone and were compared to control (CT) rats, which received water followed by ambient air. On day 29, rats were euthanized and blood samples were collected for aminotransferase enzymes (AST and ALT), creatinine, and urea analysis. Liver and kidney were weighted, dissected, fixed, and stained with hematoxylin and eosin for morphological analysis. Our results showed that necrosis was elevated in the AL, TB, and mainly the ALTB group in both liver and kidney of rats. Serum levels of AST and ALT were reduced by cigarette smoke exposure, independently of alcohol use. Serum creatinine levels increased after tobacco smoke exposure. On the other hand, TB and AL groups decreased serum urea levels, and their association restored that decrease. Absolute liver and kidney weights were lower in the cigarette smoke exposure rats. Lastly, body weight gain was lower in TB group and combined use restored it. Thus, we may infer that the use of alcohol, exposure to tobacco cigarette smoke or, mainly, their association promotes liver and kidney injuries, and this damage is related with biochemical changes in rats.

A facile method to achieve dopamine polymerization in MOFs pore structure for efficient and selective removal of trace lead (II) ions from drinking water

Heavy metals are seriously hazardous contaminants and drinking water has been identified as an important route of human exposure to them. Herein, to efficiently and selectively remove trace heavy metal ions, a facile method was reported to achieve the slow polymerization of dopamine in the cages of MIL-100 (Fe) via ultrasonic treatment followed by the hydrolysis of the urea. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Brunner-Emmet-Teller (BET) and pore size distribution determination confirmed the formation of the polydopamine (PDA) and binding with the unsaturated Fe³⁺ site in MIL-100 (Fe) pores. The composite not only retained pore structure of MOFs but also contained abundant reactive functional groups. When initial lead concentration was 150 ppb and 20 ppm calcium coexisted at pH of 6.5 ± 0.25, the effluent lead concentration met the safe drinking water standard in several tens of seconds, and decreased to 1.13 ppb in 10 min. The adsorption rate reached 99.35%. The synthetic strategy effectively overcomes mass transfer resistance of trace heavy metal ions and provides a facile approach to prepare adsorption materials for efficient and selective removal of trace heavy metal ions from drinking water.

[Results of the Dry Eye Research Grant Award 2016]

The Sicca-Förderpreis (Dry Eye Award) supports the development of scientific research on the pathogenesis, diagnostics, and treatment of dry eye and ocular surface diseases. It is awarded after a limited call for proposals in German-speaking countries, written application and selection of the award winner after evaluation by a jury of ophthalmologists working in basic and clinical science. In this article examples of the results of funded projects of the Sicca-Förderpreis 2016 are cursorily described, which were presented at the Ophthalmological Academy of Germany 2019 (Augenärztliche Akademie Deutschland 2019) and therefore provide an insight into current scientific developments. The role of muscarinic receptors and those of urea in the pathogenesis of dry eye as well as the (missing) correlation of tear film stability, viscosity and surface tension are highlighted. A project on the early detection of ocular involvement in graft versus host disease and the idea of treating meibomian gland dysfunction with eyelid surgery techniques are also groundbreaking. The outlined projects represent the potential for further substantial developments in the understanding, diagnostics and treatment of dry eye; however, their long-term clinical relevance still needs to be established.

Transformation and fate of urea in pit-toilet blackwater after discharge to environment

Studies on urea transformation reactions in blackwater are limited as urea rapidly hydrolyses under anaerobic condition. Since ammonium content of blackwater mainly originates from urine-urea, studying urea hydrolysis reactions is important to predict potential nitrate loads in aquifers from on-site sanitation facilities. In this study, urea spiked blackwater samples from pour flush pit toilet are used to examine the urea-ammonium pathways at varying initial urea concentrations and temperature. Based on laboratory results, the annual nitrate load imposed by the urea constituent of blackwater in a hard rock aquifer is predicted. Laboratory results illustrated that experimental temperature of 37 °C and pH range of 6.7 to 8.1 facilitated optimum urease enzyme activity at the initial substrate concentration of 500 mg/L. The Q₁₀ value for urea transformation reactions indicated that increase in temperature has positive influence on enzyme activity. The reduction in urea concentration with time followed first-order kinetics. Part of ammonium ions in blackwater oxidises as nitrate ions that travel to the aquifer. Upon mixing and dilution, the nitrate concentration in 1 km² of hard rock aquifer would annually increase by 0.004 mg/L due to blackwater infiltration from single household pour flush toilet.

Development and validation of two analytical methods for urea determination in compound feed, including pet food, and yeast using high-performance liquid chromatography coupled with fluorescence detection and tandem mass spectrometry

Urea is authorised in the European Union (EU) as feed additive for ruminants. Because of its high molecular nitrogen content, it is a substance for potential protein adulteration in non-ruminant feed. The EU defines a spectro-colorimetric method as an official control method for the determination of urea in feed, whereas the Association of Official Analytical Chemists (AOAC) in the United States recommends an enzymatic method. Discrepancies between results obtained by these different approaches have been reported, especially at low concentrations. Therefore, we developed and validated two methods for urea determination in compound feed, including pet food, and yeast (Saccharomyces cerevisiae) over a wide concentration range using high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and fluorescence detection (HPLC-FLD) and compared performance with a commercial enzyme kit. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 3 and 8 mg kg^-1 for LC-MS/MS and 2 and 7 mg kg^-1 for HPLC-FLD, respectively. For both methods, the variation coefficients ranged between 1.4% and 7.2% in ruminant feed used as reference material as well as spiked samples of complete feed for chicken, pet food for dogs and cats, as well as yeast. Recovery rates for spiked samples ranged from 86% to 105%. For real samples of complete feed for poultry, wet and dry pet food for cats and dogs and yeast amounts of urea between < LOD and 200 mg kg^-1 relative to a feedingstuff with a moisture content of 12% were found. In comparison with the enzyme kit, the newly developed methods proved to be less time-consuming in sample preparation and more stable regarding matrix effects.

Urea-assisted ensiling process of wilted maize stover for profitable biomethane production

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.

Effects of the nitrification inhibitor nitrapyrin and mulch on N2O emission and fertilizer use efficiency using 15N tracing techniques

Nitrous oxide (N₂O), is a potent greenhouse gas (GHG) that shares 7% of global warming around the world. Among different sources, agricultural systems account for approx. 60% of global anthropogenic N₂O emissions. These N₂O emissions are associated with the activity of nitrifiers and denitrifiers that contribute to >4 Tg (teragrams) N₂O-N emission per year. Application of nitrogen (N) fertilizers and manures in agricultural fields plays an imperative role in this regard. On the other hand nitrification inhibitors are an effective approach to minimize N₂O-N emissions from agricultural fields. Here we examined the effects of applying urea with a nitrification inhibitor (Ni) nitrapyrin and mulch (Mu) on urea transformation, nitrous oxide (N₂O) emissions, grain yield and nitrogen (N) uptake efficiency. The treatments include a control (zero N), urea (U) applied at 200 kg N ha^-1, U + Ni (Ni applied at 700 g ha^-1), U+ Mu (Mu applied at 4 t ha^-1) and U + Ni + Mu. The N₂O emission factor (EF) was 66% and 75% when U and Mu were applied, respectively. Yield-scaled N₂O emissions were lower in U and Mu by 45% and 55%, respectively. The Ni coupled with Mu enhanced urea-¹⁵N recovery by 58% and wheat grain yield by 23% and total N uptake by 30% compared with U alone. In conclusion, Ni usage is an effective strategy to mitigate N₂O emissions under field conditions.

Design and synthesis of novel glycyrrhetin ureas as anti-inflammatory agents for the treatment of acute kidney injury

To develop new anti-inflammatory drugs for the prevention and treatment of acute kidney injury, a series of novel glycyrrhetic ureas were designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. Compounds 5r-5u (2.04, 2.50, 3.25 and 2.48 μM, respectively) with acidic or neutral amino acid showed potent anti-inflammatory activity (IC₅₀ = 2-3 μM for NO inhibition), amongst them, compound 5r also inhibited tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in a dose-dependent manner. In cisplatin-induced AKI mice model, compound 5r significantly reduced the level of pro-inflammatory factors, ameliorated the pathological damage of kidney tissue, and maintained the normal metabolic capacity.

Rapid and simple determination of gabapentin in urine by ion mobility spectrometry

Gabapentin is a pharmacological agent used in the treatment of epileptic seizures. In this work, a fast method is proposed for determination of gabapentin in urine by ion mobility spectrometry (IMS) without any extraction and derivatization. ZnCl₂ was used as an effective protein precipitating reagent to remove the urine proteins. It was found that urea content of urine interferes with detection of gabapentin by IMS. By applying a delay on the carrier gas flow after injection of the sample, we could solve the urea interference to achieve gabapentin signal recovery of ∼70% in urine relative to that in water.