Interlayer Magnetic Interaction in the CrI_(3)/CrSe_(2) Heterostructure

Based on first-principles calculations, we systematically study the stacking energy and interlayer magnetic interaction of the heterobilayer composed of CrI_(3) and CrSe_(2) monolayers. It is found that the stacking order plays a crucial role in the interlayer magnetic coupling. Among all possible stacking structures, the AA-stacking is the most stable heterostructure, exhibiting interlayer antiferromagnetic interactions. Interestingly, the interlayer magnetic interaction can be effectively tuned by biaxial strain. A 4.3% compressive strain would result in a ferromagnetic interlayer interaction in all stacking orders. These results reveal the magnetic properties of CrI_(3)/CrSe_(2) heterostructure, which is expected to be applied to spintronic devices.

Field Evaluation of Alternative Testing Strategies for the Detection of HIV Infection in Beijing

To identify a cost-efficient altemative antibody testing strategy for screening and confirmation of HIV infection by rapid simple tests （RSTs） and enzyme-linked immunosorbent assays （ELISAs）. Methods Four RSTs （RST1, RST2, RST3, and RST4 ） and five ELISAs （ELISA1, ELISA2, ELISA3, ELISA4, and ELISA5） were evaluated in two phases by using banked and serum specimens prospectively collected at regional hospitals and voluntary counseling and testing （VCT） centers in Beijing. A total of 200 banked serum specimens were included in the first phase, including 62 HIV-positive, 127 HIV-negative and 11 indeterminate specimens. All specimens were tested by four RSTs and five ELISAs respectively. The second phase involved prospective testing of 389 routine specimens, including 92 HIV-positive, 287 HIV-negative, and 10 indeterminate specimens. All the specimens were tested by two RSTs （RST2 and RST4） and three ELISAs （ELISA1, ELISA3, and ELISA4）, which were selected for their respective excellent sensitivity and/or specificity. Westem blot （WB） was used as a gold standard for confirming the reactivity of all the specimens. Results Sensitivity, specificity, and efficacy were calculated for each assay in two phases. In the first phase, four assays （ELISA4, RST2, RST3, and RST4） had a specificity of 100%. For the determination of efficacy, ELISA4, RST2, and RST4 were selected in the second phase. ELISA1 and ELISA3 which have a sensitivity of 95.9% and 93.2% respectively also entered this phase. In the second phase, all the five assays （ELISA1, ELISA3, ELISA4, RST2, and RST4） had a sensitivity and specifity of over 90%. ELISA1 had a sensitivity of 99% and ELISA4 a specificity of 99%. Conclusion The sensitivity ELISA1 and the specificit of ELISA4 are comparable to ELISA/WB standard strategy. Application of this alternative testing strategy provides a cost-effective method for determining HIV prevalence in Beijing.

Theoretical Prediction of Superconductivity in Boron Kagome Monolayer:MB3(M=Be,Ca,Sr)and the Hydrogenated CaB3

Using first-principles calculations, we predict a new type of two-dimensional(2D) boride MB3(M = Be,Ca, Sr), constituted by boron kagome monolayer and the metal atoms adsorbed above the center of the boron hexagons. The band structures show that the three MB3compounds are metallic, thus the possible phononmediated superconductivity is explored. Based on the Eliashberg equation, for BeB3, CaB3, and SrB3, the calculated electron–phonon coupling constants λ are 0.46, 1.09, and 1.33, and the corresponding superconducting transition temperatures Tc are 3.2, 22.4, and 20.9 K, respectively. To explore superconductivity with higher transition temperature, hydrogenation and charge doping are further considered. The hydrogenated CaB3, i.e.,HCaB3, is stable, with the enhanced λ of 1.39 and a higher Tc of 39.3 K. Moreover, with further hole doping at the concentration of 5.8 × 1011hole/cm2, the Tc of HCaB3can be further increased to 44.2 K, exceeding the Mc Millan limit. The predicted MB3and HCaB3provide new platforms for investigating 2D superconductivity in boron kagome lattice since superconductivity based on monolayer boron kagome lattice has not been studied before.

Superconductivity Modulated by Carbonization and Hydrogenation in Two-Dimensional MXenes M2N(M=Mo,W)

The superconductivity of two-dimensional(2D)materials has extremely important research significance.To date,superconducting transition temperatures(T_(c))of 2D superconductors are still far from practical applications.Previously,2D MXene Mo_(2)N has been successfully synthesized[Urbankowski et al.Nanoscale 917722,(2017)].We systematically investigate the effects of carbonization and further hydrogenation on the stability,electronic property and superconductivity of 1T-and 2H-M_(2)N(M=Mo,W)based on first-principles calculations.The results show that the 1T-M_(2)N and 2H-M_(2)N(M=Mo,W)are all dynamically and thermodynamically stable after carbonization and further hydrogenation.After carbonization,Tc’s of 1T-M_(2)NC_(2)(M=Mo,W)are all increased,while Tc’s of 2H-M_(2)NC_(2)(M=Mo,W)are all decreased.By further hydrogenation,the Tc’s of 1T-and 2H-M_(2)NC2H2are all increased.Among all of these structures,Tcof 1T-Mo_(2)NC_(2)H_(2)is the highest one,reaching 42.7 K,and the corresponding electron-phonon coupling strengthλis 2.27.Therefore,hydrogenation is an effective method to modulate Tc’s of 2D M_(2)NC_(2)(M=Mo,W)materials.

Validation of the index for the core competence of nurses leading discharge planning for older patients in China

Objective:With the continuous advancement of aging in China,the number of older inpatients has increased sharply.Older patients have a high demand for planning their discharge services.Nurses serve as the leader of discharge planning for patients;there is a lack of reliable evaluation tool to evaluate the core competitiveness of nurses who implement discharge planning for older patients in China.The purpose of this study was to validate the index for the core competence of nurses who lead discharge planning for older patients developed by a project team through the Delphi method in the early stage.Methods:A cross-sectional questionnaire survey with 3-stage stratified sampling was used to select 1075 nurses from 17 public general hospitals in Ningxia,China.Results:The index consists of 4 first-level indicators,13 second-level indicators,and 57 third-level indicators.The results show that 57 third-level indicators had good discrimination.With exploratory factor analysis(EFA),4 common factors that explained 72.79%of the total variance were extracted.The Cronbach's a was 0.98,and the retest reliability within a 14-d interval was 0.86.The confirmatory factor analysis(CFA)results show that the fit of the index structure was good.The criterion validity was 0.73.Conclusions:The index presented excellent psychometric proper ties and can be used to measure the core competence of nurses in implementing discharge planning for older patients in China.

妊娠糖尿病患者血清Betatrophin、Omentin-1水平与糖脂代谢及胰岛素抵抗的相关性

目的探讨妊娠糖尿病(GDM)患者血清Betatrophin、脂肪组织中网膜素1(Omentin-1)水平变化特点,分析其与糖脂代谢和胰岛素抵抗的相关性。方法选择2019年5月—2020年8月承德市中心医院妇产科接诊的179例孕妇。采用酶联免疫吸附试验检测所有孕妇妊娠10~14周血清Betatrophin、Omentin-1水平。所有孕妇妊娠24~26周进行口服葡萄糖糖耐量试验(OGTT),其中,119例被诊断为GDM(GDM组),60例血糖水平正常的孕妇为对照组。检测两组孕妇的总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、空腹血糖(FBG)、空腹胰岛素(FINS)及糖化血红蛋白(HbA1c)水平。采用稳态模型计算胰岛素抵抗指数(HOMA-IR)。分析Betatrophin、Omentin-1与GDM患者糖脂代谢指标的相关性。多元线性逐步回归分析GDM患者HOMA-IR的影响因素。结果GDM组孕前体重指数(BMI)、FBG、FINS、HOMA-IR、HbA1c、TC、LDL-C、Betatrophin水平高于对照组(P<0.05),Omentin-1水平低于对照组(P<0.05)。相关性分析结果显示GDM患者血清Betatrophin与TG(rs=0464)、HOMA-IR(r=0.610)、LDL-C(r=0.512)呈正相关(均P<0.05),Omentin-1水平与孕前BMI(rs=-0.304)、LDL-C(r=-0.543)、FBG(r=-0.475)、FINS(r=-0.435)、HOMA-IR(r=-0.576)呈负相关(均P<0.05)。多元线性逐步回归分析结果显示TG、LDL-C、Betatrophin、Omentin-1是GDM患者HOMA-IR的影响因素(P<0.05)。结论GDM患者血清Betatrophin水平升高,Omentin-1水平降低,Betatrophin、Omentin-1均与GDM患者糖脂代谢、胰岛素抵抗有关。

Electronic Structure and Optical Properties of K2Ti6O13 Doped with Transition Metal Fe or Ag

Based on the experimental study of the optical properties of K2Ti6O13 doped with Fe or Ag,their electronic structures and optical properties are studied by the first-principles method based on the density functional theory（DFT）. The calculated optical properties are consistent with the experiment results. K2Ti6O13 doped with substitutional Fe or Ag has isolated impurity bands mainly stemming from the hybridization by the Fe 3d states or Ag 4d states with Ti 3d states and O 2p states and the band gap becomes narrower, the absorption edge of K2Ti6O13 thus has a clear red shift and the absorption of visible light can be realized after doping. For Fe-doped K2Ti6O13, the impurity bands are in the middle of the band gap, suggesting that they can be used as a bridge for valence band electrons transition to the conduction band. For Ag-doped K2Ti6O13,the impurity bands form a shallow acceptor above the valence band and can reduce the recombination rate of photoexcited carriers.The experimental and calculated results are significant for the development of K2Ti6O13materials that have absorption under visible light.

Successful surgical treatment of polybacterial gas gangrene confirmed by metagenomic next-generation sequencing detection:A case report

BACKGROUND We report on a case of Vibrio vulnificus(V.vulnificus)detected by metagenomics next-generation sequencing(mNGS)in a 53-year-old male patient with polymicrobial gas gangrene and successful treatment by surgery.This report raises awareness among dermatologists that when a patient is clinically suspected of a special type of pathogenic infection,the mNGS method should be preferred to identify the patient’s pathogen infection as soon as possible and then take effective treatment in time to save patients’lives.CASE SUMMARY A 53-year-old male who worked in the aquatic market complained of redness and swelling of the lower limbs,blisters and ulcers with fever for 3 d.We used mNGS to test the pathogens in ulcer secretions.The results were returned in 24 h and indicated:V.vulnificus,Fusobacterium necrophorum,Staphylococcus haemolyticus,Staphylococcus aureus,Streptococcus dysgalactiae and Klebsiella aerogenes.This patient was diagnosed with V.vulnificus infection.The emergency operation was performed immediately under combined lumbar and epidural anesthesia:Left leg expansion and exploration(August 10,2021).After surgery,we continued to use piperacillin sodium tazobactam sodium 4.5 g every 8 h and levofloxacin 0.5 g for anti-infection treatment.The patient underwent further surgery under lumbar anesthesia on August 17,2021 and August 31,2021:Left leg deactivation and skin grafting,negative pressure closed drainage and right thigh skin removal.After treatment,the transplanted flap survived.CONCLUSION We could confirm the diagnosis of Vibrio vulnificus infection within 24 h through mNGS detection and then immediately performed emergency surgery.

CHADS2 versus CHA2DS2-VASc score in assessing the stroke and throm-boembolism risk stratification in patients with atrial fibrillation:a systematic review and meta-analysis

Objective To perform a systematic review and meta-analysis of the predictive abilities of CHADS2 and CHA2DS2-VASc in stroke and thromboembolism risk stratification of atrial fibrillation (AF) patients. Methods We searched PubMed and EMBASE for Eng-lish-language literature on comparisons of the diagnostic performance between CHADS2 and CHA2DS2-VASc in predicting stroke, or sys-temic embolism, in AF. We then assessed the quality of the included studies and pooled the C-statistics and 95%confidence intervals (95%CI). Results Eight studies were included. It was unsuitable to perform a direct meta-analysis because of high heterogeneity. When analyzed as a continuous variable, the C-statistic ranged from 0.60 to 0.80 (median 0.683) for CHADS2 and 0.64-0.79 (median 0.673) for CHA2DS2-VASc. When analyzed as a continuous variable in anticoagulation patients, the subgroup analysis showed that the pooled C-statistic (95%CI) was 0.660 (0.655-0.665) for CHADS2 and 0.667 (0.651-0.683) for CHA2DS2-VASc (no significant difference). For non-anticoagulation patients, the pooled C-statistic (95%CI) was 0.685 (0.666-0.705) for CHADS2 and 0.675 (0.656-0.694) for CHA2DS2-VASc (no significant differ-ence). The average ratio of endpoint events in the low-risk group of CHA2DS2-VASc was less than CHADS2 (0.41%vs. 0.94%, P<0.05). The average proportion of the moderate-risk group of CHA2DS2-VASc was lower than CHADS2 (11.12%vs. 30.75%, P<0.05). Conclu-sions The C-statistic suggests a similar clinical utility of the CHADS2 and CHA2DS2-VASc scores in predicting stroke and thromboem-bolism, but CHA2DS2-VASc has the important advantage of identifying extremely low-risk patients with atrial fibrillation, as well as classi-fying a lower proportion of patients as moderate risk.

Study on synchrony of two uncoupled neurons under the neuron’s membrane potential stimulation

The input current of two uncoupled Hindmarsh-Rose neurons under different initial conditions is modulated by the membrane potential of the Hindmarsh- Rose neuron;and the synchronization characteristics of the two uncoupled neurons are discussed by analyzing their membrane potentials and their inter spike interval (ISI) distribution. Under the stimulation of the neuron’s membrane potential whose discharge pattern is period or the chaos, the two uncoupled neurons under different initial conditions, whose parameter r (the parameter r is related to the membrane penetration of calcium ion, and reflects the changing speed of the slow adaptation current) is different or the same, can realize the full synchronization (state synchronization) or discharge synchronization (phase synchronization), and can only be synchronized to the discharge pattern of the stimulation neuron. The synchronization characteristics are mainly related to the discharge pattern and the strength of the stimulation neuron’s membrane potential, and are little related to the parameter r and the initial state of the two uncoupled neurons. This investigation shows the characteristics of the neuron’s membrane potential affecting the synchronization process of neurons, and the neurons’ discharge patterns and synchronization process can be adjusted and controlled by the discharge pattern and the strength of the stimulation neuron’s membrane potential. This result is helpful to study synchronization and encode of many neurons or neural network.

Strong-coupling superconductivity with Tc above 70 K in Be-decorated monolayer T-graphene

Using first-principles calculations,we predict a new type of two-dimensional(2D)beryllium(Be)-decorated T-graphene named BeC_(2),where Be atoms are inserted into C–C bonds linking the carbon tetrarings of T-graphene.The band structure shows that BeC_(2)is metallic,thus,the possible phonon-mediated superconductivity is explored based on the Eliashberg equation.The calculated electron-phonon coupling(EPC)constantλis up to 4.07,and the corresponding superconducting critical temperature(Tc)is 72.1 K,approaching the liquid nitrogen temperature.The reason for the high Tc is the strong EPC.And it is proved to be an anisotropic single-gap superconductor by analyzing the superconducting gap?kof BeC_(2).The electronic susceptibility calculation shows strong nesting effect in BeC_(2).Since rare 2D superconductors show such a strong EPC constantλwhich originates from the coupling between electrons in C-pzorbital and in-plane vibrations of Be and C atoms,the predicted BeC_(2)provides a new platform for investigating strong EPC 2D superconductor.

Pretreatment HIV drug resistance in adults initiating antiretroviral therapy in China,2017

Background:After the scale-up of antiretroviral therapy(ART)for HIV infected people,increasing numbers of patients have pretreatment drug resistance(PDR).In this study,the prevalence of PDR was evaluated in adults initiating antiretroviral therapy in China.Methods:Blood samples were obtained from 1943 patients who initiated antiretroviral therapy(ART)in 2017 from 13 provinces or cities in China.Pol sequences were used to analyze drug resistance and construct transmission networks.Logistic regression model was used to estimate the potential factors associated with PDR.Results:In total,1711 eligible patients(76.0%male;87.8%aged≥25 years)were included,of which 117(6.8%)had PDR.The highest rates of PDR were 12.2%in Liangshan Prefecture of Sichuan and 9.3 and 8.9%in Dehong and Lincang Prefecture of Yunnan.A multivariate logistic regression analysis revealed that PDR was significantly higher among intravenous drug users(adjusted Odds Ratio(aOR)=2.64,95%CI:1.57–4.44)and individuals from Liangshan,Dehong,and Lincang(aOR=2.04,95%CI:1.26–3.30).In total,754 sequences were used to generate 164 transmission networks.Five transmission networks had two or three sequences containing the same mutations,two networks contained subjects from Liangshan,and one network contained subjects from Dehong.Conclusions:Overall,the PDR prevalence was moderate,with a particularly high prevalence in areas with severe HIV epidemics.These results indicate the importance of continuous PDR monitoring in patients initiating antiretroviral therapy.

High-mobility group box-1 and receptor for advanced glycation end products in preterm infants with brain injury

Background:High-mobility group box-1 (HMGB1) protein acts as an important pro-inflammatory mediator,which is capable of activating inflammation and tissue repair.HMGB1 can bind to its receptor such as advanced glycation end products (RAGE).RAGE,in turn,can promote the production of pro-inflammatory cytokines.Soluble RAGE (sRAGE) is a truncated form of the receptor comprising the extracellular domain of RAGE and can inhibit RAGE-activation.The objective of this study was to investigate whether HMGB1 and RAGE are involved in the development of brain injury in preterm infants.Methods:In total,108 infants ≤34 weeks gestation at birth were divided into 3 groups according to cranial altrasound scan:mild brain damage (n=33),severe brain damage (n=8) and no brain damage (n=67).All the placentas were submitted for pathologic evaluation.Histological chorioamnionitis (HCA) was defined as neutrophil infiltration of amniotic membranes,umbilical cord or chorionic plate.Expressions of HMGB1 and RAGE proteins were assessed by immunohistochemical analysis.The concentration of HMGB1 and sRAGE in umbilical cord blood were measured by enzyme-linked immunosorbent assay.Results:The frequency of HCA was 30.12%.HCA was associated with elevated concentrations of HMGB1 and decreased sRAGE in umbilical cord blood.The severe brain injury group demonstrated higher cord blood HMGB1 concentrations (P<0.001) and lower sRAGE concentrations (P<0.001) than both other groups.Brain injury in the premature infants was linked to intense staining for HMGB1/RAGE,particularly in inflammatory cells.Conclusions:Changes of cord blood HMGB1 and sRAGE of premature infants had direct relationship with the degree of inflammation and severity of brain damage.Monitoring sRAGE and HMGB1 levels may be helpful to predict intrauterine infection and brain injury in premature infants.

A novel synthesis of nitroform by the nitrolysis of cucurbituril

Cucurbituril has a high symmetry and rigid structure.When cucurbit[6]uril（CB[6]） was nitrolyzed with the mixed solution of acetic anhydride in fuming nitric acid,nitroform（NF） was generated.NF also can be obtained by the nitration of both CB[5,7,8].This nitration procedure provides a lower risk,inexpensive,new preparation of nitroform,and the reaction condition of this new method is very mild.

Highly spatial imaging of electrochemical activity on the wrinkles of graphene using all-solid scanning electrochemical cell microscopy

Here,all-solid scanning electrochemical cell microscopy(SECCM)is first established by filling polyacrylamide(PAM)into nanocapillaries as a solid electrolyte.A solid PAM nanoball at the tip of a nanocapillary contacts graphene and behaves as an electrochemical cell for simultaneously measuring the morphology and electrochemical activity.Compared with liquid droplet-based SECCM,this solid nanoball is stable and does not leave any electrolyte at the contact regions,which permits accurate and continuous scanning of the surface without any intervals.Accordingly,the resolutions in the lateral(x-y)and vertical(z)directions are improved to〜10 nm.The complete scanning of the wrinkles on graphene records low currents at the two sidewalls of the wrinkles and a relatively high current at the center of the wrinkles.The heterogeneity in the electrochemical activity of the wrinkle illustrates different electron transfer features on surfaces with varied curvatures,which is hardly observed by the current electrochemical or optical methods.The successful establishment of this high spatial electrochemical microscopy overcomes the current challenges in investigating the electrochemical activity of materials at the nanoscale,which is significant for a better understanding of electron transfer in materials.