Ureas Research Articles

Three-Minute Enantioselective Amino Acid Analysis by Ultra-High-Performance Liquid Chromatography Drift Tube Ion Mobility-Mass Spectrometry Using a Chiral Core-Shell Tandem Column Approach.

Fast liquid chromatography (LC) amino acid enantiomer separation of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatives using a chiral core-shell particle tandem column with weak anion exchange and zwitterionic-type quinine carbamate selectors in less than 3 min was achieved. Enantiomers of all AQC-derivatized proteinogenic amino acids and some isomeric ones (24 in total plus achiral glycine) were baseline separated (Rs > 1.5 except for glutamic acid with Rs = 1.3), while peaks of distinct amino acids and structural isomers (constitutional isomers and diastereomers of leucine and threonine) of the same configuration overlapped to various degrees. For this reason, drift tube ion mobility-mass spectrometry was added (i.e., LC-IM-MS) as an additional selectivity filter without extending run time. The IM separation dimension in combination with high-resolution demultiplexing enabled confirmation of threonine isomers (threonine, allo-threonine, homoserine), while leucine, isoleucine, and allo-isoleucine have almost identical collisional cross-section (DTCCSN2) values and added no selectivity to the partial LC separation. Density functional theory (DFT) calculations show that IM separation of threonine isomers was possible due to conformational stabilization by hydrogen bond formation between the hydroxyl side chain and the urea group. Generally, the CCSN2 of protonated ions increased uniformly with addition of the AQC label, while outliers could be explained by consideration of intramolecular interactions and additional structural analysis. Preliminary validation of the enantioselective LC-IM-MS method for quantitative analysis showed compliance of accuracy and precision with common limits in bioanalytical methods, and applicability to a natural lipopeptide and a therapeutic synthetic peptide could be demonstrated.

A computational investigation of twelve phenylurea herbicides including photoexcitation and structural relaxation

Phenylurea herbicides are widely used to control unwanted plant growth, but can linger in the environment. Photodegradation is a key mechanism by which these compounds can be transformed. This paper investigates the direct photoabsorption and relaxation of twelve phenylurea compounds (chlorbromuron, chlortoluron, diuron, fenuron, fluometuron, isoproturon, linuron, methiuron, metobromuron, metoxuron, monolinuron, monuron) using density functional theory. Ground state structures are optimized at the B3LYP-D3/def2-SVP level of theory and excited states are computed using CAM-B3LYP-D3/def2-SVPD. These molecules are found to be mostly planar and structurally similar in the ground state, with the exception of methiuron which has a significant distortion. The vertical excitation energies are affected by the presence of halogen substituents, and trends in the relaxation of these states are observed. Specifically, halogenated compounds generally have a local excited state minimum corresponding to a stretched carbon-halogen bond, phenylureas containing a methoxy group on the nitrogen have a local minimum corresponding to a twisted urea group and/or a minimum corresponding to the breaking of the nitrogen–oxygen bond between the urea and the methoxy group. The results are discussed in the context of known photodegradation mechanisms for this class of compounds.

Constructing Novel High Dielectric Constant Polyimides Containing Dipolar Pendant Groups with Enhanced Orientational Polarization.

Polymer dielectrics with high dielectric constant are urgently demanded for potential electrical and pulsed power applications. The design of polymers with side chains containing dipolar groups is considered an effective method for preparing materials with a high dielectric constant and low loss. This study synthesizes and comprehensively compare the dielectric properties of novel polyimides with side chains containing urea (BU-PI), carbamate (BC-PI), and sulfonyl (BS-PI) functional groups. The novel polyimides exhibit relatively high dielectric constant and low dielectric loss values due to the enhanced orientational polarization and suppressed dipole-dipole interactions of dipolar groups. In particular, BU-PI containing urea pendant groups presents the highest dielectric constant of 6.14 and reasonably low dielectric loss value of 0.0097. The strong γ transitions with low activation energies derived from dielectric spectroscopy measurements have been further evaluated to demonstrate the enhanced free rotational motion of urea pendant dipoles. In energy storage applications, BU-PI achieves a discharged energy density of 6.92 J cm-3 and a charge-discharge efficiency above 83% at 500 MV m-1. This study demonstrates that urea group, as dipolar pendant group, can provide polymers with better dielectric properties than the most commonly used sulfonyl groups.

Bifunctional hybrid magnetic colloidal clusters for efficient oil sludge recovery

Oil contamination of water bodies due to oil spills, industrial waste discharge, oil leaks, etc. poses a major threat to the quality of groundwater, soil, and living organisms. To combat this issue through effective environmental remediation, efficient and cost-effective materials and innovative strategies are required. Here, we report a novel bifunctional magnetic material for efficient oil sludge removal using superparamagnetic colloidal nanocrystal clusters(BSPM-CNC) of nickel ion doped iron oxide with a shell of nitrogen-activated carboxymethyl cellulose char. The BSPM-CNC is synthesized by using a single-step procedure using water as a solvent. The crystallite and cluster size were tuned by varying Ni2+ ion concentration, carboxymethyl cellulose, and urea ratio. The cluster size was found to increase, when the carboxymethyl cellulose and urea ratio was reduced, due to insufficient stabilization of the capping agent that allowed the formation of secondary structures. X-ray photoelectron spectroscopy results confirmed the presence of nitrogen in the shell because of the condensation of OH and carbonyl groups of CMC with amine groups of urea, sp2-type carbon, C-O/N and O-CO bonding states. Laser Raman spectra of the char showed two major bands G and D bands, originating from the sp2 bonds and sp2 microdomains of the bond angle disorder caused by the sp3 hybridizations, respectively. The BSPM-CNC was found to be very efficient for oil sludge removal, where an oil removal efficiency of ∼ 98% was achieved with a cluster loading of 16 mg/L. The mechanism of sorption of oil are π-π interaction between aromatic hydrocarbons and graphitic domains of BSPM-CNC, Lewis-acid base interaction between nitrogenous char and delocalized electron cloud, and absorption into the pores of clusters. Our new approach provides a new platform to produce magnetic nanoclusters for the efficient removal of oil pollutants.

Effects of Zr-based and Ni-based amorphous alloy powders on the wear resistance and corrosion behavior of polyurethane composite coatings on aluminum alloys

In this study, we present a new strategy for modifying polyurethane coatings to improve the surface performance of 6061 aluminum alloys, that is, Zr-based and Ni-based amorphous alloys were used as modified fillers. The addition of amorphous alloys resulted in alterations to the intermolecular forces among N-H bonds in the hard segments and the H-bond strength of CO bonds in the urea groups. The introduction of amorphous particles disordered the original arrangement of the fillers and gave rise to near-ring structures, which typically has a positive effect on the overall performance of the coatings. Under the synergistic effect of amorphous alloy properties and H-bond strength, hardness and wear resistance increased with increasing amorphous content. The coatings exhibit a certain degree of stealth performance, and the addition of amorphous alloys substantially improves the corrosion resistance of the coatings. Among the polyurethane/amorphous alloy composite coatings, the one containing 50 vol% Zr-based amorphous alloy has the best overall performance. Compared to previous researches, we pioneered the utilization of outstanding properties of Zr-based and Ni-based amorphous alloys to improve polyurethane coatings. This novel composite coating has great potential to be used as a corrosion-resistant coating and to be combined with good mechanical properties.

π-Conjugation effects on excited-state intermolecular proton-transfer reactions of anthracene-urea derivatives in the presence of acetate anions.

This study investigated emissive urea compounds with an anthryl moiety on one side and a substituent group (biphenyl, naphthyl, benzyl, or cyclohexyl) on the other side across from the urea group. This was performed to determine the contribution of π-conjugation on a substituent group to excited-state intermolecular proton-transfer (ESPT) reactions in the presence of acetate anions. Fluorescence lifetime measurements revealed that the rate constant of the ESPT reaction from the normal form to the tautomer form increased with the length of the π-conjugation. Considering that there were a few differences among the wavelengths of the fluorescence maxima for the anthracene-urea derivatives in the presence of acetate anions, we observed that the extension of π-conjugation promoted tautomer formation. This maintained the energy levels of the normal and tautomer forms in the excited state. Furthermore, an anthracene-urea derivative without π-conjugation did not undergo a reverse ESPT reaction, implying that π-conjugation is considerably involved in the reverse ESPT reaction from the tautomer form to the normal form.

Multiple H-bonds induced mechanically robust vat photopolymerization 3D printing poly(urethane-urea) elastomers.

Vat photopolymerization (VP) elastomers show great promise across various fields, yet they face significant challenges in achieving adequate mechanical strength, elasticity, and durability due to incomplete polymerization and weak interfacial bonding between printed layers. In this study, we introduce high-performance poly(urethane-urea) elastomers (PUEs) utilizing a dual cross-linked network (DCN) strategy compatible with VP 3D printing. This innovative approach enhances mechanical properties by incorporating multiple hydrogen-bonded urethane and urea groups. The presence of multiple hydrogen bonds facilitates energy dissipation under external mechanical stress and improves interfacial interlocking, while the covalent cross-linked network provides stability and flexibility during deformation. The resulting elastomer exhibits a tensile strength of 28.30 ± 1.10 MPa, a recovery strain of approximately 300%, and a fracture energy of 22.90 ± 4.20 kJ m-2. As a proof of concept, we demonstrate the rapid fabrication of 3D-printed stents with intricate architectures, outstanding load-bearing capabilities, and excellent biocompatibility. This strategy not only paves the way for the development of mechanically robust, complex-structured PUEs but also broadens their application scope in engineering and biomedical fields.

Effectiveness of the administration of a dietary supplement (oral urea) for the treatment of hyponatremia in SIADH

the most common cause of hyponatraemia in hospital settings is the syndrome of inappropriate antidiuretic hormone secretion (SIADH). This study compares the efficacy and safety of urea versus fluid restriction in the treatment of hyponatraemia caused by SIADH. an observational cohort study was conducted with 212 patients suffering from hyponatremia (Na+ < 135 mmol/L) due to SIADH at the Complejo Hospitalario Universitario de Pontevedra between January 2015 and May 2022. Of these, 112 patients received urea (15 g/day) and 100 were treated with fluid restriction (1 liter/day). The primary objective was to normalize sodium levels (Na ≥ 135 mmol/L). urea was significantly more effective than fluid restriction. Sodium levels increased from 126.35 to 133.9 mmol/L with urea, compared to an increase from 126.44 to 130.5 mmol/L with fluid restriction (p < 0.001). Sodium normalization was achieved in an average of 6 days with urea, compared to 8 days with fluid restriction (p = 0.04). At discharge, 59.8 % of patients treated with urea reached normal sodium levels, compared to 42 % in the fluid restriction group (p = 0.007). The 60-day mortality rate was lower in the urea group (16.1 %) compared to the fluid restriction group (32.8 %) (p < 0.007). urea is more effective than fluid restriction in normalizing sodium levels, with a better safety profile and lower 60-day mortality.

Effect of Jojoba Oil as a Growth Promoter on Body Weight, Protein Profile, and Biochemical Parameters in Turkey

This research studied the fatty acid profiles of jojoba oil and treated jojoba oil by using gas chromatography, its effect as a growth promoter on body weight, protein profile, and some biochemical parameters in Turkey. 15 healthy unvaccinated white male turkeys were divided into three groups, group 1 (control), group 2, and group 3 were continuously given treated jojoba oil in a concentration of 2.5% and 5% of the ration weight, respectively, for 90 consecutive days. The GC analysis showed that JO and TJO consist of 22 and 27 fatty acids, respectively. Also, our results illustrated a significant increase in body weight gain with a better feed conversion ratio, a significant increase in total protein and globulin levels, an elevation in superoxide dismutase and reduced glutathione levels, and a significant reduction in the amount of the consumed ration in groups 2, and 3 in comparison with group 1. No significant differences were observed between groups in AST, ALT, urea, or creatinine levels. In conclusion, TJO in a concentration of 2.5 and 5% provides a significant effect on body weight gain, feed conversion ratio, serum antioxidant capacity, and enhancing immunity but we recommend the usage of TJO in a concentration of 2.5% from an economic point of view.

A supramolecular magnetic and multifunctional Titriplex V-grafted chitosan organocatalyst for the synthesis of acridine-1,8-diones and 2-amino-3-cyano-4H-pyran derivatives.

In this research, a new supramolecular magnetic modified chitosan, namely, Fe3O4@CS-TDI-Titriplex V, was designed and prepared conveniently by grafting diethylenetriaminepentaacetic acid (Titriplex V) onto a biopolymeric chitosan backbone having urethane, urea, ester and amide functional groups. The obtained magnetic biopolymeric nanomaterial was properly characterized by different spectroscopic, microscopic or analytical methods including FTIR spectroscopy, EDX spectroscopy, XRD, FESEM, TG-DTA and VSM. The application of the supramolecular Fe3O4@CS-TDI-Titriplex V nanocomposite as a heterogeneous solid acidic organocatalyst was investigated to promote the three-component synthesis of both acridinediones and 2-amino-3-cyano-4H-pyran derivatives as important pharmaceutical scaffolds under green conditions. The obtained nanomaterial exhibited proper catalytic activity in the above mentioned transformations through multicomponent reaction (MCR) strategies. The reactions proceeded very well in the presence of the Fe3O4@CS-TDI-Titriplex V solid acid nanomaterial in EtOH to afford the corresponding acridinediones and 2-amino-3-cyano-4H-pyran derivatives in high to excellent yields. The key advantages of the present protocol include the use of a renewable, biopolymeric and biodegradable solid acid as well as a simple procedure for the preparation of the hybrid material. Furthermore, the Fe3O4@CS-TDI-Titriplex V nanomaterial was used four times with a slight decrease in its catalytic activity.

Second Coordination Sphere Effect Shifts CO2 to CO Reduction by Iron Porphyrin from Fe0 to FeI

AbstractIron porphyrins are among the most studied molecular catalysts for carbon dioxide (CO2) reduction and their reactivity is constantly being enhanced through the implementation of chemical functionalities in the second coordination sphere inspired by the active sites of enzymes. In this study, we were intrigued to observe that a multipoint hydrogen bonding scheme provided by embarked urea groups could also shift the redox activation step of CO2 from the well‐admitted Fe(0) to the Fe(I) state. Using EPR, resonance Raman, IR and UV‐Visible spectroscopies, we underpinned a two‐electron activation step of CO2 starting from the Fe(I) oxidation state to form, after protonation, an Fe(III)−COOH species. The addition of another electron and a proton to the latter species converged to the cleavage of a C−O bond with the loss of water molecule resulting in an Fe(II)−CO species. DFT analyses of these postulated intermediates are in good agreement with our collected spectroscopic data, allowing us to propose an alternative pathway in the catalytic CO2 reduction with iron porphyrin catalyst. Such a remarkable shift opens new lines of research in the design of molecular catalysts to reach low overpotentials in performing multi‐electronic CO2 reduction catalysis.

Second Coordination Sphere Effect Shifts CO2 to CO Reduction by Iron Porphyrin from Fe0 to FeI.

Iron porphyrins are among the most studied molecular catalysts for carbon dioxide (CO2 ) reduction and their reactivity is constantly being enhanced through the implementation of chemical functionalities in the second coordination sphere inspired by the active sites of enzymes. In this study, we were intrigued to observe that a multipoint hydrogen bonding scheme provided by embarked urea groups could also shift the redox activation step of CO2 from the well-admitted Fe(0) to the Fe(I) state. Using EPR, resonance Raman, IR and UV-Visible spectroscopies, we underpinned a two-electron activation step of CO2 starting from the Fe(I) oxidation state to form, after protonation, an Fe(III)-COOH species. The addition of another electron and a proton to the latter species converged to the cleavage of a C-O bond with the loss of water molecule resulting in an Fe(II)-CO species. DFT analyses of these postulated intermediates are in good agreement with our collected spectroscopic data, allowing us to propose an alternative pathway in the catalytic CO2 reduction with iron porphyrin catalyst. Such a remarkable shift opens new lines of research in the design of molecular catalysts to reach low overpotentials in performing multi-electronic CO2 reduction catalysis.

Evaluation of the Relationship Between Adropin Levels and Blood Pressure in Obese Adolescents

Background: Adropin is a bioactive protein that maintains energy balance through the metabolism of glucose and lipids. Adropin is associated with blood pressure, endothelial function, and glucose metabolism, according to reported studies. High blood pressure is one of the complications of obesity. Objectives: Our study investigated the relationship between adropin levels and systolic and diastolic blood pressure in obese adolescents. Methods: The study was conducted with a total of 88 adolescents, 45 females and 43 males, aged 10 - 18 years. The mean age of the participants was 13.79 ± 1.98 years. Participants were divided into two groups: "obese" (n = 61) and "control" (n = 27). Adolescents with a body mass index (BMI) above the 95% percentile for age, gender, and race were defined as "obese." The control group comprised adolescents with a body mass index between the 5th and 85th percentiles. A sample was taken from the forearm pit of the subjects after fasting for at least 12 hours for the determination of glucose, insulin, urea, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), C- reactive protein (CRP), total cholesterol, low-density lipoprotein- cholesterol (LDL-cholesterol), high-density lipoprotein- cholesterol (HDL- cholesterol), triglyceride, thyroid-stimulating hormone (TSH), free T4 (fT4), and 25-hydroxyvitamin D3. In both groups, systolic and diastolic blood pressures were assessed using an aneroid manometer and a suitable cuff after subjects had rested for at least 10 minutes in the outpatient clinic. The following formula determined the homeostatic model of assessment for insulin resistance (HOMA-IR): fasting insulin (uIU/mL) × fasting glucose (mg/dL) /405. An enzyme-linked immunosorbent assay (ELISA) kit was used to measure adropin levels. Results: The insulin, HOMA-IR, AST, ALT, GGT, CRP, triglyceride, and LDL-cholesterol levels of adolescents in the obese group were statistically significantly higher than those in the control group (P &lt; 0.05). HDL-cholesterol and 25-hydroxyvitamin D3 levels of adolescents in the obese group were statistically significantly lower than those of the control group (P &lt; 0.05). There was no statistically significant difference between groups in glucose, urea, creatinine, total cholesterol, TSH, fT4, and adropin levels (P &gt; 0.05). In the obese group, there was an inverse and statistically significant correlation between adropin level and diastolic blood pressure (P: 0.029; P &lt; 0.05). Conclusions: We found an inverse relationship between adropin levels and DBP but no relationship between adropin levels and SBP in obese adolescents.

Dielectric Analysis of Blended Polysulfone/Polyethylenimine Membrane Contactors for CO2 Capture.

Polysulfone membranes, used as contactors for CO2 capture, are blended with two different hyperbranched polyethyleneimines modified with benzoyl chloride (Additive 1) and phenyl isocyanate (Additive 2) in different percentages. Fourier-transformed infrared spectra evidence the presence of urea and amide groups, whereas the field emission scanning electron microscopy images show differences in the microstructure of the blended membranes. Dielectric spectra determine the motions of the side and backbone chains, which can facilitate the diffusion of CO2 . The spectra consist of six dielectric processes; three of them are due to the polysulfone (γPSf , βPSf , and αPSf ), whereas the rest are characteristic of the additive (γHPEI , βHPEI , and αHPEI ). The benzoyl chloride and phenyl isocyanate functional groups introduce variations in molecular mobility and modify the relaxations associated with the hyperbranched polyethyleneimine (HPEI). The additives also increase the conductivity of the blended membranes, which can compromise the performance of the membranes, specifically in the case of Additive 1. Ion hopping is found to be the prevailing charge transport mechanism while both relaxations, αHPEI and αPSf , are actives. These results, together with the final morphology of the membranes, may explain the greater absorption capacity of the membranes prepared with the hyperbranched polyethyleneimine modified with Additive 2.

Elastohydrodynamic lubrication performance of PUMA-PSMA supramolecular polymer gel lubricant

In this study, free radical polymerization was employed to prepare a supramolecular polymer gelator called PUMA-PSMA, containing urea groups. The incorporation of this gelator is anticipated to enhance the heat resistance of the gel lubricant. The resulting PUMA-PSMA gels demonstrate favorable mechanical strength and the ability to recover from deformation. Additionally, the PUMA-PSMA gel has a greater film thickness compared to the base oil when the oil supply is abundant. In cases of limited lubricant supply, the PUMA-PSMA gel effectively undergoes shear thinning, reducing the duration of oil starvation. These gel lubricants help prevent the loss of lubricant to some extent and are poised to serve as an innovative type of lubricant.

Kinetic modeling of thermal degradation of TDI/MDI-based flexible polyurethane foam under nitrogen and air atmospheres with Shuffled Complex Evolution algorithm: Insights from TG-FTIR analysis

This study investigates the thermal degradation mechanisms and kinetics of TDI/MDI-based flexible polyurethane foam (FPUF) under nitrogen and air atmospheres, employing thermogravimetric (TG) analysis in conjunction with TG-FTIR technique. The information gleaned from these analysis is used to construct kinetic model based on model-free approaches coupled with the Shuffled Complex Evolution optimization algorithm. The results uncovered the five-step complex thermal degradation process of TDI/MDI-based FPUF compared to TDI-based or MDI-based polyurethane in both atmospheres. In nitrogen atmosphere, this involve the dissociation of TDI- and MDI-based urethane bonds, breakage of recombined urea bonds, random chain scission of polyol, and further degradation of incompletely pyrolyzed solid products. In air atmosphere, the process emcompasses dissociation of TDI- and MDI-based urethane linkages, accelerated oxidation of polyol chains, consumption of urea groups, and combustion of partially oxidized intermediates. This work also emphasizes the limitations of solely relying on TG tests for kinetic modeling, necessitating the integration of TG tests and TG-FTIR technique to obtain a comprehensive understanding of degradation mechanisms. The significance of the acquired insights lies in their potential to reshape the design of thermo-chemical reactors, resulting in heightened resource recovery, diminished environmental impact, and a stride towards a circular economy within the polyurethane industry.

Self-renewal poly-Schiff base/gallium-based liquid metal composite coatings triggered via water for superior antimicrobial performance under water

Antimicrobial and antifouling coatings, containing either biocides or antibiotics, are extensively employed in medical facilities, marine engineering and various daily settings. Nonetheless, the misapplication of these substances has caused the proliferation of super-resistant bacteria and ecological destruction. While liquid metals present an encouraging option for antimicrobial purposes, the currently available technologies encounter issues associated with particle uniformity and the regulation of Ga3+ release. A water-triggered degradable polymer, namely polyurea-modified poly Schiff base polymer (PIPT), is designed and prepared successfully. The imine bond and urea group of PIPT efficiently generate and stabilize gallium-based liquid metal particles (GLPs). After the solvent evaporation, we obtain a poly-Schiff base/gallium-based liquid metal composite coating (PIPT/G) with a PIPT cover layer measuring approximately 1–2 μm. This cover layer successfully prevents both outflow and contamination of the liquid metal inside. PIPT/G coatings are easily applicable to various kinds of substrates, including fabric, glass and plastic tubes. The degradability of poly-Schiff base materials promotes self-renewal of the coating and control the contact state of water with liquid metal, regulating release of Ga3+. These bifunctional PIPT/G composite coatings exhibit >99 % pathogen eradication by combining antimicrobial action with self-renewal capabilities. This simple yet innovative coating method has the potential to produce highly effective antimicrobial surfaces.

Urea overdose causes pathological injury and activates necroptosis in lung of Jianzhou Da’er Goat (Capra hircus)

Urea, as a feed additive, causes poisoning in excessive dosage. In this study, we explored the mechanism of lung damage in urea poisoning on Jianzhou Da'er goat by adding different levels of urea. We used pathological histological analysis and Real-time fluorescence quantitative PCR to investigate the extent of lung damage. 9 Jianzhou Da’er goats of similar age and body condition were selected and equally randomized into three groups: 0 % urea group with 0 urea diet, 5 % urea group with 5 % urea diet and 10 % urea group with 10 % urea diet. Equal feeding was used 3 times daily (8:00 a.m., 2:00 p.m., 8:00 p.m.) in 7-d pre-feeding stage and 21-d formal experiment. After the experiment, we found the lungs of 5 % urea group and 10 % urea group both had collagen fibrosis proliferation and hemosiderin production. The nuclei of alveolar epithelial cells in the 5 % urea group were constricted and the mitochondria swelled; the alveolar epithelial cells in the 10 % urea group were necrotic and disintegrated. The expressions of RIP3 (Receptor interacting protein kinase 3) and TNF-α (tumor necrosis factor-α) mRNA in the lung of the 5 % urea group and 10 % urea group were increased significantly (P < 0.01) while the mRNA expressions of cIAP2 (cellular inhibitor of apoptosis 2) and TRADD (TNFR1-associated death domain) in the 10 % urea group were significantly decreased (P < 0.01); the mRNA expression of NEMO (NF-κB essential modulator) and Caspase-8 (cysteine aspartate protease-8) in lung of the 5 % urea group and 10 % urea group were significantly decreased (P < 0.01) and the mRNA expression of HMBG-1 (High mobility group box-1) and HSP70(Heat Shock Protein 70) were significantly up-regulated (P < 0.01). The expression of RIP3 protein in 5 % urea group and 10 % urea group were increased significantly (P < 0.01). In summary, evidence of lung damage from urea feeding includes disruption of alveolar structure, lysis of organelles, and a significant rise in genes associated with necroptosis. We expect to provide scientific value for the study of necroptosis and lung injury caused by urea toxicity.

A novel method to synthesize polyurethane-urea acrylate with high strength and toughness

Photocurable oligomer with comprehensive mechanical performance has received increasing attention. However, it is an ongoing challenge to prepare strong and tough photocurable oligomer due to the well-known trade-off between strength and toughness. In this work, a novel strategy has been developed to synthesize polyurethane-urea acrylate (PUUA) with high strength and toughness. In our strategy, a new diol containing urea group was firstly synthesized, which was then used as chain extender to prepare PUUA. The employment of diol containing urea group to prepare PUUA can avoid the direct reaction between diamine and diisocyanate in the traditional synthetic strategy of PUUA. By changing the molecular structure of the chain extender, PUUA with different side chain was synthesized. The successful synthesis of PUUA was confirmed by FTIR and 1H NMR. The UV-cured PUUA film exhibited both high mechanical strength (31 MPa) and high toughness (39.5 MJ m−3), which was 1.24 and 1.45-fold increase compared with polyurethane acrylate (PUA) film without urea group. The simultaneously enhanced mechanical strength and toughness of PUUA film should be attributed to the formation of microphase separation, which has been proved by small-angle X-ray scattering (SAXS) test. This research represents an important and universal strategy to prepare PUUA with high mechanical strength and toughness.

Building Ion-Conductive Supramolecular Elastomeric Protective Layer via Dynamic Hard Domain Design for Stable Zinc Metal Anodes.

The instability of zinc metal anode caused by zinc dendrite growth and severe parasitic reactions has significantly restricted the extensive application of rechargeable aqueous zinc-ion batteries (RAZBs). Herein, based on the strategy of dynamic hard domains, we develop an ion-conductive supramolecular elastomer consisting of Zn salts and the polyurethane-urea-polypropylene glycol polymer skeleton. This elastomer combines high mechanical strength, high ionic conductivity, decent hydrophobicity, and high adhesion to stabilize the electrode-electrolyte interface. In the elastomer system, this elastomer can dynamically adapt to the volume changes of Zn anodes during repeated zinc plating/stripping processes through the reversible dissociation/reassociation of hierarchical hydrogen bonds (H-bonds) formed by the polar groups of urea and urethane moieties. Meanwhile, the coordination of Zn2+ with soft polypropylene glycol (PPG) segments contributes to fast ion transport. This hydrophobic elastomer can also effectively inhibit water-induced corrosion by shielding the active Zn metal from the aqueous electrolyte. Based on the above synergies, the surface-modified anode shows excellent cycling stability above 550 h at a high current density of 5 mA cm-2 and a capacity of 2.5 mAh cm-2. Moreover, the assembled Zn//MnO2 full cell also displayed an enhanced electrochemical performance. This work provides inspiration for the design of solid electrolyte interphase (SEI) layers in aqueous battery chemistry to accelerate the application of RAZBs.