Effect of commercial slow-release urea product on in vitro rumen fermentation and ruminal microbial community using RUSITEC technique

Background:The objectives of this study were to determine the effect of commercial slow-release urea(SRU)on in vitro fermentation characteristics,nutrient digestibility,gas production,microbial protein synthesis and bacterial community using a rumen simulation technique(RUSITEC).The experiment was a completely randomized design with four treatments and four replications of each treatment.Treatments were:control diet(no SRU addition),control diet plus 0.28%SRU(U28),or plus 0.56%SRU(U56),and control diet that was modified substituting a part of soybean meal equivalent to 0.35%SRU(MU35;dry matter[DM]basis).The experiment consisted of 8 d of adaptation and 7 d of data and sample collection.Rumen inoculum was obtained from three ruminally fistulated Angus cows fed the same diet to the substrate incubated.Results:Digestibility of DM,organic matter(OM),crude protein(CP),fibre and starch was not affected,but daily production of gas(P<0.07)and methane(P<0.05)was quadratically increased with increasing SRU supplementation.The increase of SRU addition did not affect fermentation pH and total volatile fatty acid(VFA)production,whereas linearly(P<0.01)decreased proportion of propionate,and linearly(P<0.01)increased acetate to propionate ratio and ammonia nitrogen(N)concentration.The microbial N efficiency was also linearly(P<0.03)improved with increasing supplementation of SRU.In comparison with control diet,the dietary substitution of SRU for part of soybean meal increased(P<0.05)the digestibility of DM,OM and CP and decreased(P<0.02)the total gas production.The total VFA production and acetate to propionate ratio did not differ between control and MU35,whereas the proportion of butyrate was lower(P<0.05)and that of branched-chain VFA was greater(P<0.05)with MU35 than control diet.Total and liquid-associated microbial N production as well as ammonia N concentration were greater(P<0.03)with MU35 than control diet.Observed operational taxonomic units(OTUs),Shannon diversity index,and beta diversity of the microbial community did not differ among treatments.Taxonomic analysis revealed no effect of adding SRU on the relative abundance of bacteria at the phylum level,while at the genus level,the beneficial impact of SRU on relative abundance of Rikenellaceae and Prevotellaceae in feed particleassociated bacteria,and the abundance of Roseburia in liquid associate bacteria was greater(P<0.05)with MU35.Conclusions:Supplementation of a dairy cow diet with SRU showed potential of increase in ammonia N concentration and microbial protein production,and change fermentation pattern to more acetate production.Adding SRU in dairy cow diet also showed beneficial effect on improving digestibility of OM and fibre.The results suggest that SRU can partially substitute soybean meal in dairy cow diet to increase microbial protein production without impairing rumen fermentation.

Effects of Slow-release Nitrogen Fertilizer on Yield and Nitrogen Accumulation of Summer Maize in Shajiang Black Soil Area

[Objectives] This study was conducted to verify the field application effect of slow-release nitrogen fertilizer on summer maize in Shajiang black soil area by simultaneous sowing and fertilization, and explore the application scope and nitrogen metabolism mechanism, so as to lay a foundation for fertilizer reduction and efficiency improvement. [Methods] With maize variety Beiqing 340 and sulfur-coated urea as experimental materials, five nitrogen application levels were set, namely, control (C0), slow-release nitrogen 70 kg/hm^(2) (C70), slow-release nitrogen 140 kg/hm^(2) (C140), slow-release nitrogen 210 kg/hm^(2) (C210) and slow-release nitrogen 280 kg/hm^(2) (C280). The phosphorus and potassium fertilizers were all in accordance with the unified standard. [Results] With the application rate of slow-release nitrogen increasing, the nitrogen accumulation in organs increased first and then decreased after tasseling stage of maize. In order to reduce the fertilizing amount and increase efficiency, 210 kg/hm^(2) of slow-release nitrogen fertilizer was the best fertilizing amount for summer maize in Shajiang black soil area. [Conclusions] This study provides reference for fertilizer reduction, efficiency improvement and sustainable development of summer maize in Shajiang black soil area.

Effect of slow-release urea on soil nematode community structure in a Chinese soybean field

The effect of slow-release urea on soil nematode community structure was investigated in a soybean field in northeast China.Three treatments,no urea(CK),conventional urea(U)and slow-release urea(SRU),were arranged in a completely random design.The results show that the abundance of total nematodes was significantly higher in SRU than in CK and U.Significant differences in the abundance of bacterivores with colonizer-persister(cp)values 2–3,fungivores with cp 2 and herbivores with cp 3 were found among different treatments.Forty-one genera were identified,of which Acrobeloides,Aphelenchus and Heterodera were dominant.Soil nematode guilds and genera exhibited different responses to slow-release urea.The most trophic groups and genera had greater abundances in SRU than in CK and U.Slow-release urea had a positive effect on soil nematode community structure.

Cys C、C1q、β_(2)-MG、Urea、UA检测对初诊多发性骨髓瘤患者合并肾损伤的诊断价值

目的探讨肾功能指标胱抑素C(cystatin C,Cys C)、补体C1q(complement C1q)、β_(2)-微球蛋白(β_(2)-microglobulin,β_(2)-MG)、尿素(Urea)、尿酸(uric acid,UA)对初诊多发性骨髓瘤(multiplemyeloma,MM)患者合并肾损伤(renal impairment,RI)的诊断价值。方法回顾性分析2021年8月~2022年12月首都医科大学附属北京积水潭医院血液科收治的93例初诊MM患者的病例资料,按照血肌酐水平将MM患者分为RI组[血肌酐>176.80mmol/L(2mg/dl),n=19]及非RI组[血肌酐≤176.80mmol/L(2mg/dl),n=74],对RI组和非RI组的临床资料及实验室指标进行分析。采用单因素和多因素Logistic回归分析评价MM患者发生RI的危险因素,应用受试者工作特征(receiver operating characteristic,ROC)曲线评估危险因素对MM患者发生RI的预测价值。结果93例初诊MM患者发生RI者占25.68%,RI组轻链型占比最高(36.84%,7/19),IgG-λ型和IgA-κ型比例最低(10.53%,2/19);非RI组IgA-κ型比例最高(29.73%,22/74),IgG-λ型比例最低(12.16%,9/74)。DS分期中,RI组19例全部为Ⅲ期,非RI组72例全部为Ⅲ期。ISS分期中,RI组Ⅲ期最多(68.42%,13/19),非RI组中Ⅰ期最多(41.89%,31/74)。RISS分期中,RI组Ⅱ期和Ⅲ期最多(36.84%,7/19),非RI组Ⅱ期最多(58.11%,43/74)。DS分期和ISS分期组间差异有统计学意义(P<0.05)。RI组中Cys C、β_(2)-MG、Urea、UA水平均高于非RI组,差异均有统计学意义(P<0.05)。单因素分析结果显示,Cys C、Urea、β_(2)-MG水平异常升高是MM患者发生RI的危险因素(P<0.05),C1q对MM患者发生RI没有影响(P>0.05);多因素Logistic回归分析结果显示,Cys C、Urea、β_(2)-MG水平异常升高均是MM患者发生RI的独立影响因素(P<0.05)。Cys C、Urea、β_(2)-MG预测MM患者发生RI的敏感度分别为88.9%、50.0%、94.4%,特异性分别为90.4%、100.0%、84.9%;Cys C、Urea、β_(2)-MG联合检测预测MM患者发生RI的敏感度为100.0%,特异性为87.7%。结论Cys C、Urea、β_(2)-MG均能较好地预测初诊MM患者发生RI的可能性,3项指标联合检测对MM患者发生RI具有更高的预测价值。

Effects of slow-release urea fertilizers on urease activity, microbial biomass, and nematode communities in an aquic brown soil

A field experiment was carried out at the Shenyang Experimental Station of Ecology (CAS) in order to study the effects of slow-release urea fertilizers high polymer-coated urea (SRU1), SRU1 mixed with dicyandiamide DCD (SRU2), and SRU1 mixed with calcium carbide CaC2 (SRU3) on urease activity, microbial biomass C and N, and nematode communities in an aquic brown soil during the maize growth period. The results demonstrated that the application of slow-release urea fertilizers inhibits soil urease activity and increases the soil NH4+-N content.Soil available N increment could promote its immobilization by microorganisms. Determination of soil microbial biomass N indicated that a combined application of coated urea and nitrification inhibitors increased the soil active N pool. The population of predators/omnivores indicated that treatment with SRU2 could provide enough soil NH4+-N to promote maize growth and increased the food resource for the soil fauna compared with the other treatments.

Hybrid rice yield response to potted-seedling machine transplanting and slow-release nitrogen fertilizer application combined with urea topdressing

Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.

The dynamic response of a high-density polyethylene slow-release structure under launching overload

Based on the 60 mm artillery grenade,a slow-release structure was designed to reduce the severity of ammunitions response to accidental thermal stimulation and improve the thermal stability of ammunitions.The slow-release structure was made of high-density polyethylene(HDPE) and connected the fuse and the projectile body through internal and external threads.To study the safety of the slowrelease structure under artillery launching overload,mechanical analysis of the slow-release structure was simulated via finite element analysis(FEA).The impacts of various factors(e.g.,fuse mass,number of threads,and nominal diameter of internal threads of the slow-release structure) on the connection strength of the slow-release structure were studied.A strength-prediction model based on the fuse mass and internal thread parameters was established by fitting the maximum effective stress of the slowrelease structure.This led to good prediction results.In conclusion,this study provides references and theoretical support for the design of thermal protection structures insensitive to ammunition.

Optimization of slow-release fertilizer application improves lotus rhizome quality by affecting the physicochemical properties of starch

To achieve the dual goals of high yield and good quality with low environmental costs,slow-release fertilizer(SRF)has been widely used in lotus cultivation as new type of fertilizer instead of traditional nitrogen fertilizer.However,the optimal amount of SRF and how it would promote lotus rhizome quality remain unclear.This study was designed to investigate the photosynthetic characteristics and the synthesis,accumulation,and physicochemical properties of lotus rhizome starches under six SRF levels(CK,S1,S2,S3,S4,and S5).Compared with CK(0 kg ha^(–1)),the net photosynthetic rate(P_(n))and SPAD values of leaves remained at higher levels under SRF treatment.Further research showed that SRF increased the lotus rhizome yield,the contents of amylose,amylopectin,and total starch,and the number of starch granules.Among the six SRF levels,S3(1035 kg ha^(–1))showed the greatest difference from CK and produced the highest levels.With the increasing SRF levels,the peak,hot and final viscosities decreased at first and then increased,but the setback viscosity and pasting temperature increased.In order to interpret these changes at the molecular level,the activities of key enzymes and relative expression levels of starch accumulation related genes were analyzed.Each of these parameters also increased under SRF treatment,especially under the S3 treatment.The results of this study show that SRF,especially S3(1035 kg ha^(–1)),is a suitable fertilizer option for lotus planting which can improve lotus rhizome quality by affecting starch accumulations related enzymes and genes.These results will be useful for SRF application to high-quality lotus rhizome production with low environmental costs.

Impacts and Demonstration Effects of Applying Long-acting Slow-release Fertilizer on Economic Yield of Peanut

[Objectives]To study the impacts and demonstration effects of long-acting slow-release fertilizer application on economic yield of peanut.[Methods]The 25,30,35,40,45,50 kg of long-acting slow-release fertilizers were applied to 667 m 2 of peanuts,and different amounts of urea were applied together.[Results]Applying 40 kg of long-acting slow-release fertilizer and 10.45 kg of urea had the best effect.Compared with the application of ordinary compound fertilizers,the plants did not age prematurely,the leaf diseases were mild,the stems and leaves remained dark green when harvested,and the stems and leaves had a longer functional period.Bearing shoots increased by 1.7,single-plant full pods increased by 2.4,double-seed peanuts increased by 3.2,empty pods decreased by 0.5,and single-seed peanuts decreased by 0.7.The experimental demonstration results show that the spring-sowed peanuts had an average yield increase of 29.0-67.2 kg/667 m 2,and the yield increase rate was 7.35%-16.89%,and the difference was extremely significant.[Conclusions]In the high-yield cultivation of peanuts,the application of long-acting slow-release fertilizer can be promoted to improve peanut production.

Microwave-assisted exploration of the electron configuration-dependent electrocatalytic urea oxidation activity of 2D porous NiCo_(2)O_(4) spinel

Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR.

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy

BACKGROUND Helicobacter pylori(H.pylori)infection has been well-established as a significant risk factor for several gastrointestinal disorders.The urea breath test(UBT)has emerged as a leading non-invasive method for detecting H.pylori.Despite numerous studies confirming its substantial accuracy,the reliability of UBT results is often compromised by inherent limitations.These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H.pylori infection.AIM To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H.pylori infection in adult patients with dyspepsia.METHODS We conducted an independent search of the PubMed/MEDLINE,EMBASE,and Cochrane Central databases until April 2022.Our search included diagnostic accuracy studies that evaluated at least one of the index tests(^(13)C-UBT or ^(14)C-UBT)against a reference standard.We used the QUADAS-2 tool to assess the methodo-logical quality of the studies.We utilized the bivariate random-effects model to calculate sensitivity,specificity,positive and negative test likelihood ratios(LR+and LR-),as well as the diagnostic odds ratio(DOR),and their 95%confidence intervals.We conducted subgroup analyses based on urea dosing,time after urea administration,and assessment technique.To investigate a possible threshold effect,we conducted Spearman correlation analysis,and we generated summary receiver operating characteristic(SROC)curves to assess heterogeneity.Finally,we visually inspected a funnel plot and used Egger’s test to evaluate publication bias.endorsing both as reliable diagnostic tools in clinical practice.CONCLUSION In summary,our study has demonstrated that ^(13)C-UBT has been found to outperform the ^(14)C-UBT,making it the preferred diagnostic approach.Additionally,our results emphasize the significance of carefully considering urea dosage,assessment timing,and measurement techniques for both tests to enhance diagnostic precision.Nevertheless,it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

Pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy for activating water and urea oxidation

Exploitation of oxygen evolution reaction(OER)and urea oxidation reaction(UOR)catalysts with high activity and stability at large current density is a major challenge for energy-saving H_(2) production in water electrolysis.Herein,we use the pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy activated by NiFe_(2)O_(4)(FeNi/NiFe_(2)O_(4)@NC)for efficiently increasing the performance of water and urea oxidation.Due to the tensile strain effect on FeNi/NiFe_(2)O_(4)@NC,it provides a favorable modulation on the electronic properties of the active center,thus enabling amazing OER(η_(100)=196 mV)and UOR(E_(10)=1.32 V)intrinsic activity.Besides,the carbon-coated layers can be used as armor to prevent FeNi alloy from being corroded by the electrolyte for enhancing the OER/UOR stability at large current density,showing high industrial practicability.This work thus provides a simple way to prepare high-efficiency catalyst for activating water and urea oxidation.

Evaluation of urea breath test as a diagnostic tool for Helicobacter pylori infection in adult dyspeptic patients

In this editorial,we discuss the article in the World Journal of Gastroenterology.The article conducts a meta-analysis of the diagnostic accuracy of the urea breath test(UBT),a non-invasive method for detecting Helicobacter pylori(H.pylori)infection in humans.It is based on radionuclide-labeled urea.Various methods,both invasive and non-invasive,are available for diagnosing H.pylori infection,inclu-ding endoscopy with biopsy,serology for immunoglobulin titers,stool antigen analysis,and UBT.Several guidelines recommend UBTs as the primary choice for diagnosing H.pylori infection and for reexamining after eradication therapy.It is used to be the first choice non-invasive test due to their high accuracy,specificity,rapid results,and simplicity.Moreover,its performance remains unaffected by the distribution of H.pylori in the stomach,allowing a high flow of patients to be tested.Despite its widespread use,the performance characteristics of UBT have been inconsistently described and remain incompletely defined.There are two UBTs available with Food and Drug Administration approval:The 13C and 14C tests.Both tests are affordable and can provide real-time results.Physicians may prefer the 13C test because it is non-radioactive,compared to 14C which uses a radioactive isotope,especially in young children and pregnant women.Although there was heterogeneity among the studies regarding the diagnostic accuracy of both UBTs,13C-UBT consistently outperforms the 14C-UBT.This makes the 13C-UBT the preferred diagnostic approach.Furthermore,the provided findings of the meta-analysis emphasize the significance of precise considerations when choosing urea dosage,assessment timing,and measurement techniques for both the 13C-UBT and 14C-UBT,to enhance diagnostic precision.

Efficient C-N coupling in electrocatalytic urea generation on copper carbonate hydroxide electrocatalysts

Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.

Asymmetric configuration activating lattice oxygen via weakening d-p orbital hybridization for efficient C/N separation in urea overall electrolysis

Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and complex by-products separation.To this end,we introduce the lattice oxygen oxidation mechanism(LOM),propelling a novel UOR route using a modified CoFe layered double hydroxide(LDH)catalyst termed CFRO-7.Theoretical calculations and in-situ characterizations highlight the activated lattice oxygen(O_(L))within CFRO-7 as pivotal sites for UOR,optimizing the reaction pathway and accelerating the kinetics.For the urea overall electrolysis application,the LOM route only requires a low voltage of 1.54 V to offer a high current of 100 mA cm^(-2) for long-term utilization(>48 h).Importantly,the by-product NCO^(-)−is significantly suppressed,while the CO_(2)2/N_(2) separation is efficiently achieved.This work proposed a pioneering paradigm,invoking the LOM pathway in urea electrolysis to expedite reaction dynamics and enhance product selectivity.

Response of the Maize Variety EV87-28 to a Fertilization Strategy Involving Indorama Granular Urea on Ferralsol in the Central Ivory Coast

In Côte d’Ivoire, the decline in soil fertility strongly impacts the productivity of maize (Zea mays L.) on heavily leached ferralitic soil. In this study, the general objective was therefore to improve the productivity of maize EV87-28 on the Ferralsols in pre-forested areas during different cropping seasons. Eight (8) micro-plots were set up according to a total randomization device with three repetitions. Two factors were studied: nitrogen fertilizer modalities (main factor) and crop season (secondary factor). Growth, flowering and yield parameters were measured and analyzed. The results showed that there was no interaction between the nitrogen fertilizer factor and the cropping season factor. In addition, this study showed the short rainy season had the most positive impact on growth, flowering and yield parameters than the long rainy season. The results also showed that the different nitrogen fertilizer modalities had no statistically different effects on growth, flowering and yield parameters. However, quantitative differences were reported, highlighting one nitrogen fertilizer modality, which is the combination of urea granule + farm manure (75% urea indorama granules and 25% farm manure). The combination of urea granule + farm manure (75% urea indorama granules and 25% farm manure) had the best effect on corn grain yield. So, the combination of urea (75%) and manure (25%), that resulted in yield gain, could be recommended for corn fertilization during the small rainy season.

Brain Urea as a Potential Biomarker of Neoplasm Progression

Metabolic reprogramming is a key feature driving oncogenesis in cancers. Recent studies have revealed that protein metabolism is largely altered in gliomas facilitating its malignant growth. Urea is the end product of nitrogen metabolism which is mainly produced by arginase. The interdependence of arginase and other biochemical mechanisms triggered scientific research interest. This research aimed to investigate the relationships between the urea as the main parameter of protein metabolism and glioma progression. It was also the most pronounced relationship between urea and the level of the nuclear protein Ki-67 as a marker of proliferative activity and O-6-methylguanine-DNA methyltransferase (MGMT), which performs DNA repair. Postoperative material from 20 patients with gliomas of different grades of anaplasia was analyzed.

Atomically dispersed Ni electrocatalyst for superior urea-assisted water splitting

Urea oxidation reaction(UOR) has been selected as substitution for oxygen evolution reaction ascribing to its low thermodynamic voltage as well as utilization of nickel as electrocatalyst.Herein,we report the formation of nickel single atoms(Ni-SAs) as exceptional bifunctional electrocatalyst toward UOR and hydrogen evolution reaction(HER) in urea-assisted water splitting.In UOR catalysis,Ni-SAs perform a superior catalytic performance than Ni-NP/NC and Pt/C ascribing to the formation of HOO-Ni-N_(4) structure evidenced by in-situ Raman spectroscopy,corresponding to a boosted mass activity by 175-fold at 1.4 V vs.RHE than Ni-NP/NC.Furthermore,Ni-SAs requires only 450 mV overpotential to obtain HER current density of 500 mA cm^(-2).136 mA cm^(-2) is achieved in urea-assisted water splitting at1.7 V for Ni-SAs,boosted by 5.7 times than Pt/C-IrO_(2) driven water splitting.

Engineering hierarchical quaternary superstructure of an integrated MOF-derived electrode for boosting urea electrooxidation assisted water electrolysis

Controllable design of the catalytic electrodes with hierarchical superstructures is expected to improve their electrochemical performance.Herein,a self-supported integrated electrode(NiCo-ZLDH/NF)with a unique hierarchical quaternary superstructure was fabricated through a self-sacrificing template strategy from the metal–organic framework(Co-ZIF-67)nanoplate arrays,which features an intriguing well-defined hierarchy when taking the unit cells of the NiCo-based layered double hydroxide(NiCo-LDH)as the primary structure,the ultrathin LDH nanoneedles as the secondary structure,the mesoscale hollow plates of the LDH nanoneedle arrays as the tertiary structure,and the macroscale three-dimensional frames of the plate arrays as the quaternary structure.Notably,the distinctive structure of NiCo-ZLDH/NF can not only accelerate both mass and charge transfer,but also expose plentiful accessible active sites with high intrinsic activity,endowing it with an excellent electrochemical performance for urea oxidation reaction(UOR).Specially,it only required the low potentials of 1.335,1.368 and 1.388 V to deliver the current densities of 10,100 and 200 mA cm^(-2),respectively,much superior to those for typical NiCo-LDH.Employing NiCo-ZLDH/NF as the bifunctional electrode for both anodic UOR and cathodic HER,an energy-saving electrolysis system was further explored which can greatly reduce the needed voltage of 213 mV to deliver the current density of 100 mA cm^(-2),as compared to the conventional water electrolysis system composed of OER.This work manifests that it is prospective to explore the hierarchically nanostructured electrodes and the innovative electrolytic technologies for high-efficiency electrocatalysis.

A combination of straw incorporation and polymer-coated urea offsets soil ammonia and nitrous oxide emissions in winter wheat fields

The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.