Baeyer–Villiger oxidation of cyclohexanone catalyzed by cordierite honeycomb washcoated with Mg–Sn–W composite oxides

In this work, a series of Mg–Sn–W oxide powder catalysts with different tungsten oxide contents(0, 15 wt% and 30 wt%) were prepared and washcoated on cordierite honeycomb monoliths to produce monolithic catalysts,which were tested for the Baeyer–Villiger oxidation of cyclohexanone. The obtained monolithic catalysts,which combined the advantages of both homogeneous and heterogeneous catalysts, showed high catalytic efficiency and overcame the problems of product separation that occurred in the homogeneous catalytic process.SEM and EDX tests showed that the catalytic coating, with a thickness of approximately 20 μm, was compact and homogeneous, and an enlarged BET surface area was indicated by N_2 adsorption–desorption compared with the bare cordierite honeycomb. The chemical properties on the catalytic surface of the powder and monolithic catalysts were characterized by XPS, which indicated the tin and tungsten on the catalysts exhibited their full oxide states and presented mainly as stannate and tungstate, as confirmed by XRD and FTIR characterizations.Moreover, the catalytic activity test indicated that the tungsten content of the catalysts played an important role in catalytic efficiency and that monolithic catalysts were produced without obvious catalytic activity loss compared with the corresponding powders.(M)W30, which exhibited excellent mechanical stability and maintained high activity after recycling three times, was the optimal catalyst, showing a high selectivity that exceeded 86%and a conversion above 64%. Therefore, the structured Mg–Sn–W oxide catalysts have great potential for application in practical production.

可持续固相合成高分散PdAg合金纳米颗粒用于电催化氢氧化和氢析出反应

固相研磨作为一种新型可持续的合成方法,近年来引起了人们广泛关注,为负载型金属合金纳米催化剂的制备提供了新思路.尽管有关合金催化剂研究取得了系列进展,但现有制备方法大多存在操作步骤复杂、形貌难以控制等问题,严重制约了合金催化剂的规模化应用.本文发展了一种可持续化策略,即于室温下在玛瑙研钵中直接研磨合成了一系列高分散在碳载体上的小尺寸PdAg合金纳米颗粒(PdAg/C).此法无需任何溶剂和有机试剂,保证了整个过程简单便捷、绿色环保,同时确保了PdAg合金纳米颗粒表面清洁无污染,利于样品的催化应用.利用TEM,XRD和XPS表征技术对系列PdAg/C样品的组成及形貌进行了深入探究.TEM结果表明,所得催化剂中金属颗粒尺寸较小(4.9±1.03 nm),且高度分散在碳载体表面.XRD结果表明,Pd9Ag1/C,Pd5Ag5/C和Pd1Ag9/C催化剂特征衍射峰位于对应的Pd/C和Ag/C衍射峰之间,且会随着Ag含量的不断增加逐渐向低角度偏移.XPS结果表明,三个催化剂中均存在Pd,Ag两种元素,且随着Ag含量的增加,它们的Pd 3d结合能逐渐正移;而随着Pd含量的不断增加,三样品的Ag 3d结合能逐渐负向偏移.由此可见,采用可持续固相合成法成功制得了碳负载的PdAg合金纳米颗粒.一系列对比实验表明,PdAg合金纳米颗粒的尺寸和分散度显著依赖于NaOH,而与碳载体的形貌、比表面积和类型无明显关系.将系列PdAg/C样品用于碱性电催化氢氧化(HOR)和析氢反应(HER)时,均展现出高的催化性能.其中,Pd9Ag1/C催化性能最佳,在HOR中,质量交换电流密度和面积交换电流密度分别为26.5 A gPd^–1和0.033 mA cmPd^–2;在HER中,电流密度为10 mA cm^–2时所需过电位仅为68 mV;此外,Pd9Ag1/C催化剂经过1000圈CV循环测试后,催化活性未显著衰减,对两个目标反应均展现出优异的电化学稳定性.PdAg/C高催化活性主要归因于两个方面:(1)PdAg合金纳米颗粒表面洁净、尺寸小且分散均匀,能提供大量可利用的活性位点;(2)Pd与Ag之间强的协同与合金效应使得催化剂具有最佳的本征活性.

Prescription analysis of traditional chinese medicine for COVID-19treatment

Background:Coronavirus disease 2019 is still spreading all over the world and without any specific medicine.Traditional Chinese medicine has played an important role in the control of epidemics in China and accumulated many experiences.The aim of this study is to summarize the law of traditional Chinese medicine and provide reference for coronavirus disease 2019 traditional Chinese medicine treatment.Methods:We collected the treatment plans of traditional Chinese medicine for coronavirus disease 2019 in 24 provinces of China to evaluate the basic Chinese medicine formulas,and the efficacy types,frequency,“Four Characters”,“Five Tastes”,“Channel Tropism”of herbal medicines.Combination rules between medicines were calculated by Apriori algorithm and Clementine12.0.Results:The formulas for“Relieving Exterior Syndrome”,“Expelling Dampness”,“Clearing Heat”and“Supplementing”have highest proportion.In prevention period and medical observation period,the medicines mainly have effect for“Clearing Heat”,“Relieving Exterior Syndrome”and“Supplementing”.In treatment period,medicines for“Clearing Heat”,“Relieving Superficies”and“Relieving Dampness”had higher frequency.The“Four Characters”of Chinese medicines in all treatment plans were mainly“Cold”and“Warm”.Medicines in the treatment plans always belong to“Pungent Taste”,“Bitter Taste”and“Sweet Taste”.For“Channel Tropism”,most medicines turned over to the“Lung”,“Stoma”and“Spleen”.The common medicine combinations in the recommended formulas during the prevention period and medical observation period were medicines for“Qi-Supplementing”and“Relieving Superficies”.In treatment period(mild,moderate,severe/critical),medicines for“Dampness Expelling”,“Relieving Superficies”and“Qi-Supplementing”were combined in a high frequency.In recovery period,the medicines for“Dispelling Dampness”combined the medicines for“Promoting Blood Circulation”with highest frequency.Conclusions:We found the characteristics of medicine and prescription rules of traditional Chinese medicine for the treatment of coronavirus disease 2019 and provided scientificity and effectiveness of it.More importantly,it provides reference for the development of new clinical prescriptions for coronavirus disease 2019.

Dexmedetomidine affects the malignant biological behavior of glioma cells via miR-760/HDGF

Objective:To investigate the effect of dexmedetomidine on the malignant biological behavior of glioma cells and its mechanism.Methods:Human glioma cell line A172 was cultured in vitro and treated with different concentrations(50,100,200,400,800 mg/L)of dexmedetomidine.The effect of dexmedetomidine on the proliferation of A172 cells was detected by MTT.Flow cytometry was used to detect the effect of dexmedetomidine on the apoptosis of A172 cells.Transwell chamber assay was used to detect the effect of dexmedetomidine on the migration and invasion of A172 cells.The effects of dexmedetomidine on the expression of miR-760 and HDGF were detected by real-time quantitative PCR(qRT-PCR)and Western blot.Dual luciferase reporter assays were used to examine the effect of miR-760 overexpression on wild-type and mutant HDGF luciferase activities.miR-760 mimics and miR-con were transfected into A172 cells to detect changes in cell proliferation,apoptosis,migration and invasion.Western blot was used to detect the expression of MMP-2,MMP-9,Cleaved caspase-3 and Cleaved PARP protein.Results:Dexmedetomidine significantly reduced the survival rate of glioma cells(P<0.05),decreased the number of migrated cells and the number of invasive cells(P<0.05),and inhibited the expression of HDGF,MMP-2 and MMP-9(P<0.05).However,it could increase the apoptosis rate(P<0.05)and promote the expression of miR-760,Cleaved caspase-3 and Cleaved PARP(P<0.05).The effect was obvious when the concentration reaches 800 mg/L.Luciferase reporter gene results confirmed that miR-760 can inhibit the luciferase activity of the 3'-UTR region of HDGF(P<0.05).After transfection of miR-760 mimics,cell viability was significantly lower than that of miR-con group(P<0.05),and the number of migrated cells and invasive cells were significantly decreased(P<0.05),and the expression levels of MMP-2 and MMP-9 were significantly decreased(P<0.05),but the apoptosis rate was significantly increased(P<0.05),and the expression levels of Cleaved caspase-3 and Cleaved PARP were significantly increased(P<0.05).Interference with the expression of miR-760 reversed the effect of dexmedetomidine on the biological behavior of glioma cells.Conclusion:Dexmedetomidine attenuates the proliferation,migration and invasion of glioma cells through miR-760/HDGF and promotes apoptosis.

A rare complication after radiofrequency ablation in the treatment of colorectal liver metastasis: A case report

Radiofrequency ablation(RFA)is one of the safe and effective treatments of colorectal cancer with liver metastasis,which has the advantages of minimally invasive,fewer complications,short hospitalization time and repeatable operation.A special case with advanced transverse colon carcinoma was treated by RFA in our center.All the procedures were performed,which were recommended by the guideline.An intestinal perforation occurred on the second day after the RFA,then surgeon performed emergency surgery,unfortunately,anastomotic leakage occurred on the 21st day after the operation,yet after conservative medical treatment,the patient achieved remission of symptoms and discharged from the hospital.Rare complications occurred after RFA in the treatment of colorectal cancer with liver metastasis are unpredictable,which could affect the efficacy of RFA and performance status of patients.Further investigation of the mechanism of these complications is warranted urgently,which might offer more effective methods against these rare complications.

The Safe Navigation of Partial Motion Planning Based on “Cooperation” with Roadside Fixed Sensors in VANET

In recent years, many methods of safe vehicle navigation and partial motion planning (PMP) have been proposed in vehicular ad-hoc network (VANET) field. In order to improve the limitation of traditional PMP, this paper presents a novel effective way to plan motion with cooperation of roadside fixed sensors (RFSs). With their cooperation, the vehicles can get the surrounding information quickly and effectively, and give highly accurate projections about the near future conditions on road. After proposing our algorithm, the worst case is analyzed and methods are found to solve the problem. Finally we conduct one elemental contrast experiment, driver situation awareness, with or without the “cooperation” of RFSs in highway scenarios. The result shows that the vehicles can make a better PMP based on the forward conditions received from RFSs, and extend the warning distance obviously when emergency happens.

Electrostatic generator enhancements for powering IoT nodes via efficient energy management

Electrostatic generators show great potential for powering widely distributed electronic devices in Internet of Things(IoT)applications.However,a critical issue limiting such generators is their high impedance mismatch when coupled to electronics,which results in very low energy utilization efficiency.Here,we present a high-performance energy management unit(EMU)based on a spark-switch tube and a buck converter with an RF inductor.By optimizing the elements and parameters of the EMU,a maximum direct current output power of 79.2 mW m^(-2)rps^(-1)was reached for a rotary electret generator with the EMU,achieving 1.2 times greater power output than without the EMU.Furthermore,the maximum power of the contact-separated triboelectric nanogenerator with an EMU is 1.5 times that without the EMU.This excellent performance is attributed to the various optimizations,including utilizing an ultralow-loss spark-switch tube with a proper breakdown voltage,adding a matched input capacitor to enhance available charge,and incorporating an RF inductor to facilitate the high-speed energy transfer process.Based on this extremely efficient EMU,a compact self-powered wireless temperature sensor node was demonstrated to acquire and transmit data every 3.5 s under a slight wind speed of 0.5 m/s.This work greatly promotes the utilization of electrostatic nanogenerators in practical applications,particularly in IoT nodes.

Crowd intelligence in AI 2.0 era

The Internet based cyber-physical world has profoundly changed the information environment for the development of artificial intelligence(AI), bringing a new wave of AI research and promoting it into the new era of AI 2.0. As one of the most prominent characteristics of research in AI 2.0 era, crowd intelligence has attracted much attention from both industry and research communities. Specifically, crowd intelligence provides a novel problem-solving paradigm through gathering the intelligence of crowds to address challenges. In particular, due to the rapid development of the sharing economy, crowd intelligence not only becomes a new approach to solving scientific challenges, but has also been integrated into all kinds of application scenarios in daily life, e.g., online-tooffline(O2O) application, real-time traffic monitoring, and logistics management. In this paper, we survey existing studies of crowd intelligence. First, we describe the concept of crowd intelligence, and explain its relationship to the existing related concepts, e.g., crowdsourcing and human computation. Then, we introduce four categories of representative crowd intelligence platforms. We summarize three core research problems and the state-of-the-art techniques of crowd intelligence. Finally, we discuss promising future research directions of crowd intelligence.

Thyroid function reference ranges during pregnancy in a large Chinese population and comparison with current guidelines

Background: A correct thyroid function reference range is important for the accurate diagnosis of thyroid disease during pregnancy. However, there is no consensus on whether thyroid function reference ranges in Chinese population should follow the America Thyroid Association (ATA) guidelines. This study aimed to establish a thyroid function reference range more suited to the Chinese population by evaluating the current thyroid function reference range in pregnant Chinese women and comparing it to the ATA guidelines. Methods: A total of 52,027 pregnant women were enrolled from January 2013 to December 2016. Thyroid stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibody (TPOAb) levels were tested during the first and third trimesters of pregnancy. Reference ranges of TSH and FT4 were established from the 2.5th and 97.5th percentiles of the TPOAb-negative population of women. The Mann-Whitney U test was used to compare thyroid hormones between the TPOAb-positive and TPOAbnegative groups. Results: We obtained that the TSH reference ranges were 0.03 to 3.52 mU/L and 0.39 to 3.67 mU/L, and the FT4 reference ranges were 11.7 to 19.7 pmol/L and 9.1 to 14.4pmol/L, in the firstand third trimester, respectively. If we used the 2011 ATA criteria about 7.0% and 4.0% pregnant women would be over diagnosed in first and third trimester, respectively, compared with local population thyroid hormone reference. When we compared our local criteria with the new 2017 ATA criteria, about 1.2% and 0.8% pregnant women would have a missed diagnosis in first and third trimester, respectively. Conclusions: Based on our data, which is in line with the current ATA guidelines, a population-based thyroid function reference range would be the first choice for diagnosis of thyroid disease during pregnancy in China. In case such population-based thyroid function reference ranges are unavailable in the east of China, our reference ranges can be adopted, if the same assay is used.

Study on the Microscopic Network Model of PVA Hydrogel Based on the Tensile Behavior

Hydrogel is an emerging material widely used in the biological field.The tensile properties of hydrogel mainly depend on its polymer network,but due to the complex microstructure of the network,some properties of the hydrogel have yet to be qua nt itatively analyzed.In this article,we built a three-dimensional random fiber net work to characterize the micros tructure of a hydrogel.The fibers were simplified as elastic beams,and the cross-links were regarded as"hinges."Combined with the macroscopic experimental results,the influence of the change of fiber length and the relationship between the polymer content and the cross-link density were studied.The model was verified by the quasi-static tensile test results of real PVA hydrogel materials with different fiber contents.The results show that the model can well match the tensile stress-strain curve and tensile strength of the PVA hydrogels with different fiber contents.The change in micros true ture of the fiber network induces nonlinear behaviors,and although the cross-link number increases with the increase in polymer content,the cross-link density(per unit PVA chain length)of the PVA hydrogel slightly decreases as the content increases.

The impact of ESG on financial performance:a revisit with a regression discontinuity approach

This study revisits the question of“whether firms are doing well by doing good?”.We examine shareholders-sponsored corporate socially responsible(CSR)proposals related to Environmental,Social,and Governance(ESG)that are voted to pass or fail by a small margin.The adoption of those“close call”proposals is regarded as equivalent to a random assignment of CSR policies and,therefore,provides a quasi-experimental setting to capture the causal influence of CSR on firm performance.We apply the regression discontinuity design(RDD)and find that CSR proposals’passage leads to a significant positive abnormal return on the voting day.The results are robust with both parametric and nonparametric approaches of RDD and different polynomial orders.However,we fail to identify a significant change in financial performance in the long-term.One possible reason is that passing a CSR proposal could be symbolic,rather than substantial.

Altered Matrix Metalloproteinases Expression in Placenta from Patients with Gestational Diabetes Mellitus

To the Editor：Gestational diabetes mellitus （GDM） is defined as glucose intolerance with the onset of pregnancy and is related to increased maternal and fetal risks.Incidence of GDM varies in different countries and the prevalence ranges between 4% and 17%. GDM is one of the most common medical complications of pregnancy,negatively affecting fetal development and metabolic balance.If untreated,GDM can cause fetal malformation,macrosomia,fetal growth retardation,and even intrauterine fetal death.Recent studies have shown correlations between GDM and postpartum insulin resistance,pregnancy-induced hypertension,and dyslipidemia.GDM has also been shown to be associated with placental abnormalities including altered placental function,oxidative stress,and vascular dysfunction.

经右侧锁骨下动脉入路介入治疗106例单中心经验

目的探讨经右侧锁骨下动脉穿刺入路行介入治疗的安全性。方法回顾性收集临沧市人民医院介入科自2014年7月至2021年5月经右侧锁骨下动脉入路行介入治疗的106例患者,男14例,女92例,平均年龄(40.36±13.06)岁,其中行妇科介入治疗66例,下肢动脉血栓形成置管溶栓30例,下肢静脉血栓置管溶栓6例,肝癌介入治疗3例,其他介入治疗1例。结果105例患者成功穿刺置管,穿刺成功率99.05%,1例穿刺失败更换左侧股动脉入路成功行右下肢动脉栓塞置管溶栓术。所有病例无危及生命的严重并发症发生,其中1例患者穿刺后出现胸壁血肿,后经加压包扎好转出院。结论经右侧锁骨下动脉穿刺入路行介入治疗安全,便于术者操作,术后患者无需卧床,舒适性高,护理方便,尤其适用于需要置管持续溶栓和持续动脉灌注化疗的患者。