Interplay between mesenchymal stromal cells and the immune system after transplantation: implications for advanced cell therapy in the retina

Advanced mesenchymal stromal cell-based therapies for neurodegenerative diseases are widely investigated in preclinical models.Mesenchymal stromal cells are well positioned as therapeutics because they address the underlying mechanisms of neurodegeneration,namely trophic factor deprivation and neuroinflammation.Most studies have focused on the beneficial effects of mesenchymal stromal cell transplantation on neuronal survival or functional improvement.However,little attention has been paid to the interaction between mesenchymal stromal cells and the host immune system due to the immunomodulatory properties of mesenchymal stromal cells and the long-held belief of the immunoprivileged status of the central nervous system.Here,we review the crosstalk between mesenchymal stromal cells and the immune system in general and in the context of the central nervous system,focusing on recent work in the retina and the importance of the type of transplantation.

Genetic Variations and Nonalcoholic Fatty Liver Disease:Field Synopsis,Systematic Meta-Analysis,and Epidemiological Evidence

Objective To systematically summarize the published literature on the genetic variants associated with nonalcoholic fatty liver disease(NAFLD).Methods Literature from Web of Science,PubMed,and Embase between January 1980 and September 2022 was systematically searched.Meta-analyses of the genetic variants were conducted using at least five data sources.The epidemiologic credibility of the significant associations was graded using the Venice criteria.Results Based on literature screening,399 eligible studies were included,comprising 381 candidate gene association,16 genome-wide association,and 2 whole-exome sequencing studies.We identified 465 genetic variants in 173 genes in candidate gene association studies,and 25 genetic variants in 17 genes were included in the meta-analysis.The meta-analysis identified 11 variants in 10 genes that were significantly associated with NAFLD,with cumulative epidemiological evidence of an association graded as strong for two variants in two genes(HFE,TNF),moderate for four variants in three genes(TM6SF2,GCKR,and ADIPOQ),and weak for five variants in five genes(MBOAT7,PEMT,PNPLA3,LEPR,and MTHFR).Conclusion This study identified six variants in five genes that had moderate to strong evidence of an association with NAFLD,which may help understand the genetic architecture of NAFLD risk.

MH-STRALP:A scoring system for prognostication in patients with upper gastrointestinal bleeding

BACKGROUND Upper gastrointestinal bleeding(UGIB)is a common medical emergency and early assessment of its outcomes is vital for treatment decisions.AIM To develop a new scoring system to predict its prognosis.METHODS In this retrospective study,692 patients with UGIB were enrolled from two cen-ters and divided into a training(n=591)and a validation cohort(n=101).The clinical data were collected to develop new prognostic prediction models.The en-dpoint was compound outcome defined as(1)demand for emergency surgery or vascular intervention,(2)being transferred to the intensive care unit,or(3)death during hos-pitalization.The models’predictive ability was compared with previously esta-blished scores by receiver operating characteristic(ROC)curves.RESULTS Totally 22.2%(131/591)patients in the training cohort and 22.8%(23/101)in the validation cohort presented poor outcomes.Based on the stepwise-forward Lo-gistic regression analysis,eight predictors were integrated to determine a new post-endoscopic prognostic scoring system(MH-STRALP);a nomogram was de-termined to present the model.Compared with the previous scores(GBS,Rock-all,ABC,AIMS65,and PNED score),MH-STRALP showed the best prognostic prediction ability with area under the ROC curves(AUROCs)of 0.899 and 0.826 in the training and validation cohorts,respectively.According to the calibration cur-ve,decision curve analysis,and internal cross-validation,the nomogram showed good calibration ability and net clinical benefit in both cohorts.After removing the endoscopic indicators,the pre-endoscopic model(pre-MH-STRALP score)was conducted.Similarly,the pre-MHSTRALP score showed better predictive value(AUROCs of 0.868 and 0.767 in the training and validation cohorts,respectively)than the other pre-endoscopic scores.CONCLUSION The MH-STRALP score and pre-MH-STRALP score are simple,convenient,and accurate tools for prognosis prediction of UGIB,and may be applied for early decision on its management strategies.

A Quality Evaluation System for Dissertation Based on Fuzzy Analytic Hierarchy Process

A dissertation is a research report or scientific paper written by an author to obtain a certain degree. It reflects postgraduates’ research achievements and the educational quality of an institute, even a country. To construct an optimized quality evaluation system for postgraduate dissertation (QESPD), we summarized the influencing factors and invited 10 experienced specialists to rate and prioritize them based on fuzzy analytic hierarchy process. Four primary indicators (innovation, integrity, scientificity and normativity) and 16 sub-indicators were selected to form the evaluation system. The order of primary indicators by weight, was innovation (0.4269), scientificity (0.2807), integrity (0.1728) and normativity (0.1196). The top five sub-dimensions were theoretical originality, scientific value, data reliability, design rationality and evidence credibility. To demonstrate the effectiveness of the proposed system, a case study was performed. In the case study, it was demonstrated that the established two-index-hierarchy QESPD in this study was a more scientific and reasonable evaluation system worthy of promotion and application.

Cost analysis of radical resection of malignant breast tumors under the China Healthcare Security Diagnosis Related Groups payment system

BACKGROUND Breast cancer is one of the most common malignant tumors in women worldwide and poses a severe threat to their health.Therefore,this study examined patients who underwent breast cancer surgery,analyzed hospitalization costs and structure,and explored the impact of China Healthcare Security Diagnosis Related Groups(CHS-DRG)management on patient costs.It aimed to provide medical institutions with ways to reduce costs,optimize cost structures,reduce patient burden,and improve service efficiency.AIM To study the CHS-DRG payment system’s impact on breast cancer surgery costs.METHODS Using the CHS-DRG(version 1.1)grouping criteria,4073 patients,who underwent the radical resection of breast malignant tumors from January to December 2023,were included in the JA29 group;1028 patients were part of the CHS-DRG payment system,unlike the rest.Through an independent sample t-test,the length of hospital stay as well as total hospitalization,medicine and consumables,medical,nursing,medical technology,and management expenses were compared.Pearson’s correlation coefficient was used to test the cost correlation.RESULTS In terms of hospitalization expenses,patients in the CHS-DRG payment group had lower medical,nursing,and management expenses than those in the diagnosis-related group(DRG)non-payment group.For patients in the DRG payment group,the factors affecting the total hospitalization cost,in descending order of relevance,were medicine and consumable costs,consumable costs,medicine costs,medical costs,medical technology costs,management costs,nursing costs,and length of hospital stay.For patients in the DRG nonpayment group,the factors affecting the total hospitalization expenses in descending order of relevance were medicines and consumable expenses,consumable expenses,medical technology expenses,the cost of medicines,medical expenses,nursing expenses,length of hospital stay,and management expenses.CONCLUSION The CHS-DRG system can help control and reduce unnecessary medical expenses by controlling medicine costs,medical consumable costs,and the length of hospital stay while ensuring medical safety.

Surgical treatment of liver cancer and pancreatic cancer under the China Healthcare Security Diagnosis Related Groups payment system

BACKGROUND Data from the World Health Organization’s International Agency for Research on Cancer reported that China had the highest prevalence of cancer and cancer deaths in 2022.Liver and pancreatic cancers accounted for the highest number of new cases.Real-world data(RWD)is now widely preferred to traditional clinical trials in various fields of medicine and healthcare,as the traditional research approach often involves highly selected populations and interventions and controls that are strictly regulated.Additionally,research results from the RWD match global reality better than those from traditional clinical trials.AIM To analyze the cost disparity between surgical treatments for liver and pancreatic cancer under various factors.METHODS This study analyzed RWD 1137 cases within the HB1 group(patients who underwent pancreatectomy,hepatectomy,and/or shunt surgery)in 2023.It distinguished different expenditure categories,including medical,nursing,technical,management,drug,and consumable costs.Additionally,it assessed the contribution of each expenditure category to total hospital costs and performed cross-group comparisons using the non-parametric Kruskal–Wallis test.This study used the Steel–Dwass test for post-hoc multiple comparisons and the Spearman correlation coefficient to examine the relationships between variables.RESULTS The study found that in HB11 and HB13,the total hospitalization costs were significantly higher for pancreaticoduodenectomy than for pancreatectomy and hepatectomy.Although no significant difference was observed in the length of hospital stay between patients who underwent pancreaticoduodenectomy and pancreatectomy,both were significantly longer than those who underwent liver resection.In HB15,no significant difference was observed in the total cost of hospitalization between pancreaticoduodenectomy and pancreatectomy;however,both were significantly higher than those in hepatectomy.Additionally,the length of hospital stay was significantly longer for patients who underwent pancreaticoduodenectomy than for those who underwent pancreatectomy or liver resection.CONCLUSION China Healthcare Security Diagnosis Related Groups payment system positively impacts liver and pancreatic cancer surgeries by improving medical quality and controlling costs.Further research could refine this grouping system and ensure continuous effectiveness and sustainability.

Violence study of healthcare workers and systems in the Caribbean:ViSHWaS-Caribbean study

BACKGROUND Violence against healthcare workers(HCWs)in the Caribbean continues to prevail yet remains underreported.Our aim is to determine the cause,traits,and consequences of violence on HCWs in the Caribbean.AIM To determine the cause,traits,and consequences of violence on HCWs in the Caribbean.METHODS This research adopted an online cross-sectional survey approach,spanning over eight weeks(between June 6th and August 9th,2022).The survey was generated using Research Electronic Data Capture forms and followed a snowballing strategy to contact individuals using emails,social media,text messages,etc.Logistic regression analysis was performed to evaluate the variables that influence violence,including gender,age,years of experience,institution type,and night shift frequency.RESULTS The survey was completed by 225 HCWs.Females comprised 61%.Over 51%of respondents belonged to the 21 to 35 age group.Dominica(n=61),Haiti(n=50),and Grenada(n=31)had the most responses.Most HCWs(49%)worked for government academic institutions,followed by community hospitals(23%).Medical students(32%),followed by attending physicians(22%),and others(16%)comprised the most common cadre of respondents.About 39%of the participants reported experiencing violence themselves,and 18%reported violence against colleague(s).Verbal violence(48%),emotional abuse(24%),and physical misconduct(14%)were the most common types of violence.Nearly 63%of respondents identified patients or their relatives as the most frequent aggressors.Univariate logistic regression analyses demonstrated that female gender(OR=2.08;95%CI:1.16-3.76,P=0.014)and higher frequency of night shifts(OR=2.22;95%CI:1.08-4.58,P=0.030)were associated with significantly higher odds of experiencing violence.More than 50%of HCWs felt less motivated and had decreased job satisfaction post-violent conduct.CONCLUSION A large proportion of HCWS in the Caribbean are exposed to violence,yet the phenomenon remains underreported.As a result,HCWs’job satisfaction has diminished.

Comparative Study of the Reliability and Complexity of Symmetrical and Asymmetrical Cryptosystems for the Protection of Academic Data in the Democratic Republic of Congo

In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any modern company. A companys operational and historical data contains strategic and operational knowledge of ever-increasing added value. The emergence of a new paradigm: big data. Today, the value of the data scattered throughout this mother of knowledge is calculated in billions of dollars, depending on its size, scope and area of intervention. With the rise of computer networks and distributed systems, the threats to these sensitive resources have steadily increased, jeopardizing the existence of the company itself by drying up production and losing the interest of customers and suppliers. These threats range from sabotage to bankruptcy. For several decades now, most companies have been using encryption algorithms to protect and secure their information systems against the threats and dangers posed by the inherent vulnerabilities of their infrastructure and the current economic climate. This vulnerability requires companies to make the right choice of algorithms to implement in their management systems. For this reason, the present work aims to carry out a comparative study of the reliability and effectiveness of symmetrical and asymmetrical cryptosystems, in order to identify one or more suitable for securing academic data in the DRC. The analysis of the robustness of commonly used symmetric and asymmetric cryptosystems will be the subject of simulations in this article.

Benefits of Dielectric Oil Regeneration Systems in Power Transmission Networks: A Case Study

The criticality of transformers and reactors in the power transmission network and the paramount importance of ensuring their reliability through maintenance of the insulating oil is known. This paper presents a comprehensive examination of the efficacy and economic viability of a dielectric oil regeneration system, as implemented by the Transmission System Maintenance Department (TSMD) of the Independent Power Transmission Operator (IPTO), Greece’s sole transmission operator. Through a detailed chemical analysis and performance evaluation, we assess the impact of the regeneration system on treated insulating oil quality over multiple cycles. The study reveals that the electrical properties of the insulating oil are fully restored after regeneration, negating the need to fully replace it, while the investment becomes cost-neutral within weeks from the commissioning of the regeneration system. This economic analysis, coupled with the system’s environmental benefits of reducing waste oil generation, positions the dielectric oil regeneration system as a compelling solution for the maintenance of power transmission assets.

Promoting Ethical Sensitivity in Nursing Education:A Systematic Review of Case Study-Based Health Education

Introduction: Nursing ethical sensitivity refers to a nurse’s capacity for thoughtful consideration of ethical issues when faced with dilemmas. In the nursing domain, ethical dilemmas arise when nurses face challenges in making sound ethical decisions during clinical practice. These challenges may stem from conflicts between personal values and professional responsibilities. Methodology: Articles downloaded from Pub Med, CNKI, and Google Scholar were reviewed. Results: After rigorous screening, a meticulous analysis was conducted, encompassing 10 articles and involving a substantial cohort of 2863 participants. Existing literature revealed variations in the ethical dilemmas faced by nurses across different departments. The ethical sensitivity of nurses also varies, with higher ethical sensitivity correlating with stronger empathetic abilities. Zhen et al. classified the causes of ethical dilemmas into four main categories: (1) Ethical dilemmas arising from personal reasons of nursing students;(2) Ethical dilemmas stemming from the actions of teachers;(3) Ethical dilemmas triggered by patients;(4) Ethical dilemmas resulting from miscellaneous reasons. Conclusion: According to literature findings, nursing ethical sensitivity was positively linked to the nurse’s ethical decision-making ability. A case study-oriented teaching program has proven effective in enhancing ethical sensitivity among nursing students.

Research on the Current Situation of China’s Higher Education Students Studying Abroad in the Context of Higher Education Internationalization

In the context of education internationalization,the internationalization of higher education has become a major trend in the field of education in most countries,with international student education as the core.This phenomenon promotes cultural exchanges and integration among countries as well as higher education reform,which is of great significance in enhancing the international influence of higher education in each country.However,there are also some challenges faced by higher education students when studying abroad.The article digs into the origin and history of studying abroad,analyzes the current situation and reasons for higher education students in China to study abroad,discusses the opportunities and challenges faced by higher education students in China when studying abroad,and analyzes the trend of studying abroad in China.

Performance Analysis of a Solar Continuous Adsorption Refrigeration System

A study is conducted on the performances of a solar powered continuous-adsorption refrigerator considering two particular days as references cases,namely,the summer solstice(June 21st)and the autumn equinox(September 21st).The cooling capacity,system performance coefficient and the daily rate of available cooling energy are assessed.The main goal is to compare the performances of a solar adsorption chiller equipped with a hot water tank(HWT)with an equivalent system relying on solar collectors with no heat storage module.The daily cooling rates for the solar refrigerator are found to be 102.4 kWh and 74.3 kWh,respectively,on June 21st and on September 21st,using a total collector’s area of 43.47 m2.The corresponding values for the adsorption chiller equipped with a hot water tank of 2 m3(and using a total collector’s area of 72.45 m2),are 127.1 kWh and 106.13 kWh,respectively.

Dimensioning Urban Drainage Systems in Housing Subdivisions in the Amazon Using Different Hydrological Models

Hydrological studies for sizing urban drainage systems in the Amazon have often been neglected and little investigated for rainwater projects. This research evaluated alternative hydrological models used in sizing urban drainage network projects in subdivisions with subsidized houses in the Amazonian region in Brazil. Statistical tests of these models were performed for both original and alternative scenarios. The methodological steps we conducted as follows: 1) evaluate the dimensioning of infrastructure project networks, considering two case studies contemplated by the Calha Norte Program (CNP) in the state of Amapá;2) test the statistical significance of the dimensioning of network diameters (α < 0.05), considering a) benchmark project (MD or M1) approved by the Ministry of Defense;b) determination of concentration time (Ct) and rainfall intensity-duration-frequency (IDF) relationships, as well as estimating diameters using alternative models. The results indicated a significant influence on the diameters of the projected rainfall networks (p < 0.05), suggesting that alternative models predicted more unfavorable flow peaks than the original model. We conclude that the benchmarking model underestimated the diameter of the project compared to alternative models, which means the optimized Ct parameter significantly impacts dimensioning estimates in rainwater projects in these Amazonian municipalities. This suggests that underestimated parameters in MD may cause inefficiency in the stormwater system projects in future similar scenarios.

Power Distribution System Regulation (A Review)

This article presents a framework and a comprehensive model to optimize the regulation of the electricity distribution system.The regulatory requirements of the electricity distribution system and research gaps in this field are among the important outputs of this review article.In each of the presented parts of the framework,it has reviewed,introduced and listed the regulatory studies of the electricity distribution system.In order to calculate the PDSR(regulation of power distribution system)framework,governance first presents,its goals,and its development plan in the distribution sector,and discusses the regulatory position in it.After that,in the electricity distribution system,it describes the role of the regulator in the goals and plans of the electricity distribution system,and introduces the types of regulation of the electricity distribution system,and finally,discusses about the place of data in the regulation and its requirements,and the effects of regulation in the evolution and stability of the electricity distribution system.

Crucial, But not Systematically Investigated: Rock Glaciers, the Concealed Water Reservoirs of the Himalayas: An Opinion

The current article is an opinion on the sensitivity of high mountain regions which are the most fragile,sensitive and vulnerable to ongoing climate change.Its impacts are especially severe on the high mountain communities owing to their weak socio-economic profile,limited livelihood resources and agricultural land.The melting of glaciers and changes in the snow cover under the climate change scenario is leading to the scarcity of freshwater supplies,affecting both local and downstream communities.Changes in the precipitation patterns have been suggested to cause droughts,impact restricted agriculture,and limit the availability of water for domestic use.Additionally,the high mountain areas contain distinct flora and fauna,and climate change is not just altering them,but also has resulted in biodiversity loss as species are unable to adapt to the changing climate.Because of its higher altitudes and semi-arid to arid climate,the consequences of climate change are more evident in the higher Himalayas.Climate change is affecting the availability of key resources,such as freshwater and agriculture and pasture lands,resulting in food and water insecurity and their reliance on imports from other regions.As a result,high mountain communities in the Himalayas are progressively shifting to higher glacier valleys in search of suitable cultivable land with adequate irrigation.People are engaging in agro-pastoral activities around thermokarst lakes(Oasis)atop rock glaciers as part of this endeavour.Such actions underscore the crucial role of rock glaciers in dealing with and adjusting to the consequences of climate change.Despite its relevance,rock glacier research in the Himalayan region is still in its infancy.The purpose of this work is to emphasise the significance of these major climate-resilient water resources,as well as the methodology that must be adopted for their systematic and compressive investigations.

基于WOFOST模型与遥感数据同化的县级尺度玉米估产研究

区域尺度的作物生长动态监测和产量预测对于保障粮食安全和农业政策的制定具有重要参考依据。遥感数据同化应用极大提高了作物估产的时效性和精度。为及时、准确地实现县级尺度粮食产量的估测,以及提升产量估测的精度,以辽宁省铁岭县为研究区,采用WOFOST(world food studies)模型与遥感同化相结合的方法对铁岭县玉米进行估产研究。通过采用扩展傅里叶幅度敏感性检验算法(extened Fourier amplitude sensitivity test,EFAST)敏感性分析方法实现玉米估产敏感性参数的分析,以及本地化;通过采用参数自动率定程序PEST(parameter estimation)实现参数的优化,验证结果为采样点产量的平均误差为852.39 kg·hm^(-2),模型模拟的精度达到92.82%。为进一步提高和优化模型估产精度,将遥感反演得到的叶面积指数采用集合卡尔曼滤波算法与模型模拟的叶面积指数进行数据同化,平均误差从同化前的852.39 kg·hm^(-2)降低为435.01 kg·hm^(-2),估产精度从92.82%提高到96.33%,有效提高了WOFOST模型估产的精度。结果表明:水分对玉米的生长发育限制并不大,其产量形成主要受光温影响,对温度、光能利用效率和最大同化速率有关的参数具有较高的敏感性;优化后的模型能够较好模拟铁岭县玉米生长发育情况,产量验证表明优化后的模型模拟的效果较好,但仍存在一定的误差;比值植被指数与叶面积指数的相关性最高,反演模型精度较好,反演结果表明叶面积指数在抽雄吐丝期差距较大,而在成熟期的差距不大;经过作物模型与遥感数据同化之后,估产的精度得到明显提高,说明遥感与作物模型同化是一种有效地提高作物估产和产量预测精度的方法。

Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases

Autophagy is a cellular catabolic process characterized by the formation of double-membrane autophagosomes.Transmission electron microscopy is the most rigorous method to clearly visualize autophagic engulfment and degradation.A large number of studies have shown that autophagy is closely related to the digestion,secretion,and regeneration of gastrointestinal(GI)cells.However,the role of autophagy in GI diseases remains controversial.This article focuses on the morphological and biochemical characteristics of autophagy in GI diseases,in order to provide new ideas for their diagnosis and treatment.

Cumulative effects of excess high-normal alanine aminotransferase levels in relation to new-onset metabolic dysfunction-associated fatty liver disease in China

BACKGROUND Within the normal range,elevated alanine aminotransferase(ALT)levels are associated with an increased risk of metabolic dysfunction-associated fatty liver disease(MAFLD).AIM To investigate the associations between repeated high-normal ALT measurements and the risk of new-onset MAFLD prospectively.METHODS A cohort of 3553 participants followed for four consecutive health examinations over 4 years was selected.The incidence rate,cumulative times,and equally and unequally weighted cumulative effects of excess high-normal ALT levels(ehALT)were measured.Cox proportional hazards regression was used to analyse the association between the cumulative effects of ehALT and the risk of new-onset MAFLD.RESULTS A total of 83.13%of participants with MAFLD had normal ALT levels.The incidence rate of MAFLD showed a linear increasing trend in the cumulative ehALT group.Compared with those in the low-normal ALT group,the multivariate adjusted hazard ratios of the equally and unequally weighted cumulative effects of ehALT were 1.651[95%confidence interval(CI):1.199-2.273]and 1.535(95%CI:1.119-2.106)in the third quartile and 1.616(95%CI:1.162-2.246)and 1.580(95%CI:1.155-2.162)in the fourth quartile,respectively.CONCLUSION Most participants with MAFLD had normal ALT levels.Long-term high-normal ALT levels were associated with a cumulative increased risk of new-onset MAFLD.

Epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China:a hospital-based retrospective study

Traumatic spinal cord injury is potentially catastrophic and can lead to permanent disability or even death.China has the largest population of patients with traumatic spinal cord injury.Previous studies of traumatic spinal cord injury in China have mostly been regional in scope;national-level studies have been rare.To the best of our knowledge,no national-level study of treatment status and economic burden has been performed.This retrospective study aimed to examine the epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China at the national level.We included 13,465 traumatic spinal cord injury patients who were injured between January 2013 and December 2018 and treated in 30 hospitals in 11 provinces/municipalities representing all geographical divisions of China.Patient epidemiological and clinical features,treatment status,and total and daily costs were recorded.Trends in the percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department and cost of care were assessed by annual percentage change using the Joinpoint Regression Program.The percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department did not significantly change overall(annual percentage change,-0.5%and 2.1%,respectively).A total of 10,053(74.7%)patients underwent surgery.Only 2.8%of patients who underwent surgery did so within 24 hours of injury.A total of 2005(14.9%)patients were treated with high-dose(≥500 mg)methylprednisolone sodium succinate/methylprednisolone(MPSS/MP);615(4.6%)received it within 8 hours.The total cost for acute traumatic spinal cord injury decreased over the study period(-4.7%),while daily cost did not significantly change(1.0%increase).Our findings indicate that public health initiatives should aim at improving hospitals’ability to complete early surgery within 24 hours,which is associated with improved sensorimotor recovery,increasing the awareness rate of clinical guidelines related to high-dose MPSS/MP to reduce the use of the treatment with insufficient evidence.

Oxygen‑Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection.Here,we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen(O)coordination on bacterial cellulose-converted graphitic carbon(Mn-O-C).Evidence of the atomically dispersed Mn-(O-C_(2))_(4)moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy.As a result,the as-synthesized Mn-O-C catalyst exhibits superior NitRR activity with an NH_(3)yield rate(RNH_(3))of 1476.9±62.6μg h^(−1)cm^(−2)at−0.7 V(vs.reversible hydrogen electrode,RHE)and a faradaic efficiency(FE)of 89.0±3.8%at−0.5 V(vs.RHE)under ambient conditions.Further,when evaluated with a practical flow cell,Mn-O-C shows a high RNH_(3)of 3706.7±552.0μg h^(−1)cm^(−2)at a current density of 100 mA cm−2,2.5 times of that in the H cell.The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn-(O-C_(2))_(4)sites not only effectively inhibit the competitive hydrogen evolution reaction,but also greatly promote the adsorption and activation of nitrate(NO_(3)^(−)),thus boosting both the FE and selectivity of NH_(3)over Mn-(O-C_(2))_(4)sites.