Response of plant,litter,and soil C:N:P stoichiometry to growth stages in Quercus secondary forests on the Loess Plateau,China

Ecological stoichiometry is an important indicator of biogeochemical cycles and nutrient limitations in terrestrial ecosystems.However,little is known about the response of ecological stoichiometry to plant growth.In this study,carbon(C),nitrogen(N),and phosphorus(P)concentrations were evaluated in plant tissues(trees,shrubs,and herbs),litter,and soil of young(≤40-year-old),middle-aged(41–60-year-old),near-mature(61–80-year-old),and mature(81–120-year-old)Quercus secondary forests on the Loess Plateau,China.Vegetation composition,plant biomass,and C stock were determined to illustrate their interaction with stoichiometry.Only tree biomass C signifi cantly increased with stand development.Leaf N and trunk P concentrationsgenerally increased,but branch P decreased with growth stage.Fine roots had the highest C and P concentrations at the middle-aged stage.In contrast,shrubs,herbs,litter,and soil C:N:P stoichiometry did not change signifi cantly during stand development.Leaf N and P were positively correlated with soil C,N,P,and their ratios.However,there was no signifi cant correlation between litter and leaves in terms of C:N:P stoichiometry.A redundancy analysis showed that soil N best explained leaf N and P variance,and tree biomass and C stock were related to biotic factors such as tree age and shrub biomass.Hierarchical partitioning analysis indicated that,compared with soil or litter variables,stand age only accounted for a relatively small proportion of leaf C,N,and P variation.Thus,secondary Quercus ecosystems might have inherent ability to maintain sensitive responses of metabolically active organs to environmental factors during stand aging.The results of this work help to elucidate the biogeochemical cycling of secondary forest ecosystems in tree development,provide novel insights into the adaptation strategies of plants in diff erent organs and growth stages,and could be used to guide fertilization programs and optimize forest structure.

Unveiling localized electronic properties of ReS2 thin layers at nanoscale using Kelvin force probe microscopy combined with tip-enhanced Raman spectroscopy

Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hundreds of nanometers, and it is difficult to characterize localized electronic properties of 2D materials at nanoscales. Herein, tip-enhanced Raman spectroscopy(TERS) is proposed to combine with KPFM to break this restriction. TERS scan is conducted on ReS2bubbles deposited on a rough Au thin film to obtain strain distribution by using the Raman peak shift. The localized contact potential difference(CPD) is inversely calculated with a higher spatial resolution by using strain measured by TERS and CPD-strain working curve obtained using conventional KPFM and atomic force microscopy. This method enhances the spatial resolution of CPD measurements and can be potentially used to characterize localized electronic properties of 2D materials.

Edible mushrooms as a potent therapeutics of subclinical thyroid dysfunction among adults,especially in obese individuals:a prospective cohort study

Background:Mushrooms are a good source of many nutrients which are potentially beneficial for chronic diseases.We speculated that due to its abundant nutrients edible mushrooms might have a beneficial effect on the prevention of subclinical thyroid dysfunction(SCTD).Therefore,we designed a large-scale cohort study to examine whether mushrooms consumption is a protective factor for SCTD in adults.Methods:This prospective cohort study investigated 6631 participants(mean age:(45.0±10.2)years;55.1%men).Edible mushrooms consumption was measured at baseline using a validated food frequency questionnaire.SCTD was defined as abnormal serum thyroid-stimulating hormone levels and normal free thyroxine.Cox proportional hazards regression models were used to examine the association of edible mushrooms consumption with incident SCTD.Results:During follow-up period,a total of 262 new cases of SCTD were identified,the incidence rate of subclinical hypothyroidism was 8.9/1000 person-years and subclinical hyperthyroidism was 7.2/1000 person-years.After adjusting potential confounding factors,the multivariable hazard ratios(95%confidence intervals)for subclinical hypothyroidism were 1.00(reference)for almost never,0.53(0.29,0.97)for 1-3 times/week and 0.30(0.10,0.87)for≥4 times/week(P for trend=0.02).It also showed edible mushrooms consumption was inversely associated with subclinical hypothyroidism in obese individuals but not non-obese individuals,the final hazard ratios(95%confidence intervals)were 0.14(0.03,0.73)(P for trend<0.01).Conclusions:This population-based prospective cohort study has firstly demonstrated that higher edible mushrooms consumption was significantly associated with lower incidence of subclinical hypothyroidism among general adult population,especially in obese individuals.

On-the-Fly Nonadiabatic Dynamics of Caffeic Acid Sunscreen Compound

As a widely-used sunscreen com-pound,the caffeic acid(CA)shows the strong UV absorption,while the photoinduced reaction mecha-nisms behind its photoprotection ability are not fully understood.We try to investigate the photoin-duced internal conversion dynam-ics of CA in order to explore the photoprotection mechanism.The most stable CA isomer is selected to examine its nonadiabatic dy-namics using the on-the-fly surface hopping simulations at the semi-empirical level of electronic-struc-ture theory.The dynamics starting from different electronic states are simulated to explore the dependence of the photoinduced reaction channels on the excitation wavelengths.Several S1/S0 conical intersections,driven by the H-atom detachments and the ring deformations,have been found to be responsible for the nonadiabatic decay of the CA.The simulation re-sults show that the branching ratios towards these intersections are modified by the light with different excitation energies.This provides the valuable information for the understanding of the photoprotection mechanism of the CA compound.

采用彩色分割立体匹配与简化点云的三维目标快速重建

本文将彩色分割立体匹配和简化点云技术用于三维目标的快速重建。对于采集的左右两幅三维目标图像,首先采用均值漂移算法进行彩色图像分割,然后按区域匹配算法进行快速立体匹配,获得初始视差,再应用置信传播法进行全局视差优化,从而得到精确的视差图与空间点云。应用空间表面曲率准则对获取的密集点云进行简化,并采用Delaunay三角剖分算法进行三维重建。实验结果表明:采用彩色图像分割与置信传播相结合,能够改善立体匹配效率并保证了匹配质量;基于曲率的点云简化,既提高了三维重建速度也得到了满意的重建效果。

在ADC(2)水平上通过从头算非绝热动力学方法模拟硝酸甲酯的光解

在ADC(2)水平上通过轨线面跳跃方法模拟了硝酸甲酯的非绝热动力学.结果证实该体系存在快速的非绝热动力学过程,导致了体系回到电子基态.当动力学从S_(1)和S_(2)电子态开始时,光解产物是CH_(3)O+NO_(2),这个发现与实验研究的结果以及更高精度的XMS-CASPT2水平上模拟出的结果一致.在ADC(2)水平上,当动力学从S3态开始时,光解产物依然是CH_(3)O+NO_(2).该研究表明:ADC(2)方法可用于研究硝酸甲酯在长波下的光解机理,然而无法用于理解其在短波段下的光解动力学.本文为在ADC(2)水平上处理类似化合物的光诱导过程提供了有价值的信息.

Antioxidant andα-glucosidase inhibitiory activity of Cercis chinensis flowers

Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.

Procoagulant constituents from Cordyceps militaris

Cordyceps militaris,belongs to Clavicipitaceae family,was investigated for its chemical compounds,and six compounds were isolated and purified by silica gel column chromatography,Sephadex LH-20 and recrystallization,and their structures were elucidated by spectral techniques and physicochemical properties as ergosterol(1),adenosine(2),cordycepin(3),ergosterol peroxide(4),tetracosanoic acid 2,3-dihydroxypropylester(5),mannitol(6).Procoagulant activity was screened by assaying the activated partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT)and fibrinogen(FIB)in vitro.The results indicated that ergosterol,adenosine,cordycepin,ergosterol peroxide and mannitol showed strong procoagulant activity.

不同类型褐藻酸钠对凝胶性能的影响研究

研究不同M/G比值及不同浓度褐藻酸钠对凝胶特性的影响。结果表明:1) 低M/G比值的褐藻酸钠形成凝胶强度大,硬度和咀嚼性高,弹性略低;高M/G比值的褐藻酸钠形成凝胶强度小,硬度和咀嚼性低,弹性好。2) 相同M/G比值的褐藻酸钠,浓度越大,制作的凝胶强度越大,口感越硬。

On the Relationship between Duration of Vegetative Growth Stage of Wheat and the Average Daily Temperature

Using the modern information technology,this paper analyzes the 20 years of experimental observation data of wheat ear differentiation research team led by Professor Cui Jinmei.It reveals that in the appropriate sowing period,there is a quartic polynomial regression relationship between the sowing period and spike primordium period,namely between duration of vegetative growth stage and the average daily temperature.It is of great significance to determining the suitable sowing period of wheat.

Enhanced photoelectrocatalytic decomplexation of Ni-EDTA and simultaneous recovery of metallic nickel via TiO_(2)/Ni-Sb-SnO_(2) bifunctional photoanode and activated carbon fiber cathode

In order to enhance Ni-EDTA decomplexation and Ni recovery via photoelectrocatalytic (PEC)process,TiO_(2)/Ni-Sb-SnO_(2)bifunctional electrode was fabricated as the photoanode and activated carbon fiber (ACF) was introduced as the cathode.At a cell voltage of 3.5 V and initial solution pH of 6.3,the TiO_(2)/Ni-Sb-SnO_(2)bifunctional photoanode exhibited a synergetic effect on the decomplexation of Ni-EDTA with the pseudo-first-order rate constant of 0.01068 min^(-1)with 180 min by using stainless steel (SS) cathode,which was 1.5 and 2.4times higher than that of TiO_(2)photoanode and Ni-Sb-SnO_(2)anode,respectively.Moreover,both the efficiencies of Ni-EDTA decomplexation and Ni recovery were improved to 98%from 86%and 73%from 41%after replacing SS cathode with ACF cathode,respectively.Influencing factors on Ni-EDTA decomplexation and Ni recovery were investigated and the efficiencies were favored at acidic condition,higher cell voltage and lower initial Ni-EDTA concentration.Ni-EDTA was mainly decomposed via·OH radicals which generated via the interaction of O_(3),H_(2)O_(2),and UV irradiation in the contrasted PEC system.Then,the liberated Ni^(2+)ions which liberated from Ni-EDTA decomplexation were eventually reduced to metallic Ni on the ACF cathode surface.Finally,the stability of the constructed PEC system on Ni-EDTA decomplexation and Ni recovery was exhibited.

The role of Class Ⅱ KNOX family in controlling compound leaf patterning in Medicago truncatula

Compound leaf development requires the coordination of genetic factors, hormones, and other signals. In this study, we explored the functions of Class Ⅱ KNOTTED-like homeobox(KNOXII)genes in the model leguminous plant Medicago truncatula. Phenotypic and genetic analyses suggest that Mt KNOX4, 5 are able to repress leafet formation, while Mt KNOX3, 9, 10 are not involved in this developmental process. Further investigations have shown that Mt KNOX4 represses the CK signal transduction, which is downstream of Mt KNOXⅠ-mediated CK biosynthesis. Additionally,two boundary genes, FUSED COMPOUND LEAF1(orthologue of Arabidopsis Class M KNOX) and NO APICAL MERISTEM(orthologue of Arabidopsis CUP-SHAPED COTYLEDON), are necessary for Mt KNOX4-mediated compound leaf formation.These findings suggest, that among the members of Mt KNOXⅡ, Mt KNOX4 plays a crucial role in integrating the CK pathway and boundary regulators,providing new insights into the roles of Mt KNOXⅡ in regulating the elaboration of compound leaves in M. truncatula.

Risk Factors Associated with the Spatiotemporal Spread of the SARS-CoV-2 Omicron BA.2 Variant—Shanghai Municipality,China,2022

Summary What is already known about this topic?Previous studies have explored the spatial transmission patterns of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and have assessed the associated risk factors.However,none of these studies have quantitatively described the spatiotemporal transmission patterns and risk factors for Omicron BA.2 at the micro(within-city)scale.

Modeling the Prediction on the Efficacy of a Homologous Third Dose of CoronaVac Against SARS-CoV-2 Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5 — China, 2020–2021

Summary What is already known about this topic?Previous studies have reported vaccine efficacy or effectiveness against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron subvariants for several vaccine platforms.However,there are currently few data on estimates of inactivated platform coronavirus disease 2019(COVID-19)vaccines,especially against the globally dominant subvariant—Omicron BA.5.

Estimating Changes in Contact Patterns in China Over the First Year of the COVID-19 Pandemic:Implications for SARS-CoV-2 Spread—Four Cities,China,2020

Introduction:Previous studies have demonstrated significant changes in social contacts during the firstwave coronavirus disease 2019(COVID-19)in Chinese mainland.The purpose of this study was to quantify the time-varying contact patterns by age in Chinese mainland in 2020 and evaluate their impact on the transmission of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Methods:Diary-based contact surveys were performed for four periods:baseline(prior to 2020),outbreak(February 2020),post-lockdown(March–May 2020),and post-epidemic(September–November 2020).We built a Susceptible-Infected-Recovered(SIR)model to evaluate the effect of reducing contacts on transmission.Results:During the post-epidemic period,daily contacts resumed to 26.7%,14.8%,46.8%,and 44.2%of the pre-COVID levels in Wuhan,Shanghai,Shenzhen,and Changsha,respectively.This suggests a moderate risk of resurgence in Changsha,Shenzhen,and Wuhan,and a low risk in Shanghai.School closure alone was not enough to interrupt transmission of SARS-CoV-2 Omicron BA.5,but with the addition of a 75%reduction of contacts at the workplace,it could lead to a 16.8%reduction of the attack rate.To control an outbreak,concerted strategies that target schools,workplaces,and community contacts are needed.Discussion:Monitoring contact patterns by age is key to quantifying the risk of COVID-19 outbreaks and evaluating the impact of intervention strategies.

试析伊拉克亚述人的族群—国家认同问题

亚述人起源于两河流域北部,以聂斯托里派和迦勒底教派信徒为主,是伊拉克最大的基督教少数群体之一。20世纪初,亚述人深受“民族自决原则”和民族主义思潮的鼓舞,以“民族”身份凝聚族群,寻求政治独立和族群共同体自治。伊拉克建国后,亚述人延续其独立活动,与英国殖民政府合作,拒绝承认其公民身份,从而催生了诸如族群认同和宗教认同挑战国家认同、族群认同遭遇国家的暴力裹挟和民族同化、族裔民族主义运动冲击并消解国家认同、库尔德政府认同与国家认同相抵牾等一系列的族群—国家认同问题。在后萨达姆时代,亚述人的认同问题在宗派碎片化和国家政局动荡的情势下进一步复杂化,未来也将继续考验伊拉克民族国家构建和族群治理的有效性。

新冠肺炎的流行病学、传播动力学、疫苗和非药物性干预措施评价的研究进展

在全球新冠肺炎持续流行、病毒变异频发的背景下,我国长期面临境外输入和本土反弹的双重压力。自新冠肺炎疫情初始,在国家自然科学基金委员会的支持下,复旦大学余宏杰研究团队运用经典流行病学、传染病学、统计学、地理信息学和生态学等多学科交叉技术,通过临床评价、构建基于群体和个体水平的传播动力学模型等,在疫情的各个阶段针对新冠肺炎的流行病学、传播动力学、疫苗和非药物性干预措施评价等领域开展了深入、系统的研究,为建立新冠肺炎流行病学特征的认识奠定了科学基础,为疫情防控、推进复工复产、制定疫苗免疫策略等提供了直接科学证据。

Removal of Cd^(2+) from water by Friedel's salt (FS:3CaO·A1_2O_3 ·CaCl_2 ·10H_2O): Sorption characteristics and mechanisms

The development of low-cost and efficient new mineral adsorbents has been a hot topic in recent years. In this study, Friedel＇s salt （FS：3CaO·A12O3 ·CaCl2 ·10H2O）, a hexagonal layered inorganic absorbent, was synthesized to remove Cd2＋ from water. The adsorption process was simulated by Langmuir and Freundlich models. The adsorption mechanism was further analyzed with TEM, XRD, FT-IR analysis and monitoring of metal cations released and solution pH variation. The results indicated the adsorbent FS had an outstanding ability for Cd（Ⅱ） adsorption. The maximum adsorption capacity of the FS for Cd（Ⅱ） removal can reach up to 671.14 mg/g. The nearly equal numbers of Cd2＋ adsorbed and Ca2＋ released demonstrated that ion-exchange （both surface and inner） of the FS for Cd（Ⅱ） played an important role during the adsorption process. Furthermore, the surface of the FS after adsorption was microscopically disintegrated while the inner lamellar structure was almost unchanged. The behavior of Cd（Ⅱ） adsorption by FS was significantly affected by surface reactions. The mechanisms of Cd2＋ adsorption by the FS mainly included surface complexation and surface precipitation. In the present study, the adsorption process was fitted better by the Langmuir isotherm model （R2 = 0.9999） than the Freundlich isotherm model （R2 = 0.8122）. Finally, due to the high capacity for ion-exchange on the FS surface, FS is a promising layered inorganic adsorbent for the removal of Cd（Ⅱ） from water.

Analysis of COVID-19 Guideline Quality and Change of Recommendations:A Systematic Review

Background.Hundreds of coronavirus disease 2019(COVID-19)clinical practice guidelines(CPGs)and expert consensus statements have been developed and published since the outbreak of the epidemic.However,these CPGs are of widely variable quality.So,this review is aimed at systematically evaluating the methodological and reporting qualities of COVID-19 CPGs,exploring factors that may influence their quality,and analyzing the change of recommendations in CPGs with evidence published.Methods.We searched five electronic databases and five websites from 1 January to 31 December 2020 to retrieve all COVID-19 CPGs.The assessment of the methodological and reporting qualities of CPGs was performed using the AGREE II instrument and RIGHT checklist.Recommendations and evidence used to make recommendations in the CPGs regarding some treatments for COVID-19(remdesivir,glucocorticoids,hydroxychloroquine/chloroquine,interferon,and lopinavir-ritonavir)were also systematically assessed.And the statistical inference was performed to identify factors associated with the quality of CPGs.Results.We included a total of 92 COVID-19 CPGs developed by 19 countries.Overall,the RIGHT checklist reporting rate of COVID-19 CPGs was 33.0%,and the AGREE II domain score was 30.4%.The overall methodological and reporting qualities of COVID-19 CPGs gradually improved during the year 2020.Factors associated with high methodological and reporting qualities included the evidence-based development process,management of conflicts of interest,and use of established rating systems to assess the quality of evidence and strength of recommendations.The recommendations of only seven(7.6%)CPGs were informed by a systematic review of evidence,and these seven CPGs have relatively high methodological and reporting qualities,in which six of them fully meet the Institute of Medicine(IOM)criteria of guidelines.Besides,a rapid advice CPG developed by the World Health Organization(WHO)of the seven CPGs got the highest overall scores in methodological(72.8%)and reporting qualities(83.8%).Many CPGs covered the same clinical questions(it refers to the clinical questions on the effectiveness of treatments of remdesivir,glucocorticoids,hydroxychloroquine/chloroquine,interferon,and lopinavirritonavir in COVID-19 patients)and were published by different countries or organizations.Although randomized controlled trials and systematic reviews on the effectiveness of treatments of remdesivir,glucocorticoids,hydroxychloroquine/chloroquine,interferon,and lopinavir-ritonavir for patients with COVID-19 have been published,the recommendations on those treatments still varied greatly across COVID-19 CPGs published in different countries or regions,which may suggest that the CPGs do not make sufficient use of the latest evidence.Conclusions.Both the methodological and reporting qualities of COVID-19 CPGs increased over time,but there is still room for further improvement.The lack of effective use of available evidence and management of conflicts of interest were the main reasons for the low quality of the CPGs.The use of formal rating systems for the quality of evidence and strength of recommendations may help to improve the quality of CPGs in the context of the COVID-19 pandemic.During the pandemic,we suggest developing a living guideline of which recommendations are supported by a systematic review for it can facilitate the timely translation of the latest research findings to clinical practice.We also suggest that CPG developers should register the guidelines in a registration platform at the beginning for it can reduce duplication development of guidelines on the same clinical question,increase the transparency of the development process,and promote cooperation among guideline developers all over the world.Since the International Practice Guideline Registry Platform has been created,developers could register guidelines prospectively and internationally on this platform.

Application of artificial intelligence in clinical diagnosis and treatment:an overview of systematic reviews

Objective This study aimed to summarize the characteristics and methodological quality of systematic reviews on the application of artificial intelligence(AI)in clinical diagnosis and treatment.Methods We systematically searched seven English-and Chinese-language literature databases to identify sys-tematic reviews on the application of AI,deep learning,or machine learning in the diagnosis and treatment of any disease published in 2020.We evaluated the methodological quality of the included systematic reviews using“A Measurement tool for the assessment of multiple systematic reviews”(AMSTAR).We also conducted meta-analyses on the diagnostic accuracy of AI on selected disease categories with a large number of included studies and low clinical heterogeneity.Results A total of 40 systematic reviews reporting 1,083 original studies were included,covering 31 diseases from 11 groups of diseases.Eleven systematic reviews were related to neoplasms and nine were systematic reviews related to diseases of the digestive system.We selected digestive system diseases for the meta-analysis.The pooled sensitivities(with 95%confidence interval(CI))of AI to assist the diagnosis of helicobacter pylori,gastrointestinal ulcers,hemorrhage,esophageal tumors,gastric tumors,and intestinal tumors(with 95%CI)were 0.91(0.83-0.95),0.99(0.76-1.00),0.95(0.83-0.99),0.90(0.85-0.93),0.90(0.82-0.95),and 0.93(0.88-0.96),respectively,and the pooled specificities were 0.82(0.77-0.87),0.97(0.86-1.00),1.00(0.99-1.00),0.80(0.71-0.87),0.93(0.87-0.97),and 0.89(0.85-0.92),respectively.The AMSTAR items“the list of included studies”(n=39,97.5%)and“the characteristics of the included studies”(n=39,97.5%)had the highest compliance among the reviews;the compliance was relatively low to the items“the consideration of publication status”(n=1,2.5%),“the consideration of scientific quality”(n=19,47.5%),“data synthesis methods”(n=18,45.0%),and“the evaluation of publication bias”(n=13,32.5%).Conclusions The main subjects of systematic reviews on AI applications in clinical diagnosis and treatment pub-lished in 2020 were diseases of the digestive system and neoplasms.The methodological quality of the systematic reviews on AI needs to be improved,paying particular attention to publication bias and the rigorous evaluation of the quality of the included studies.