Flat soliton microcomb source

Mode-locked microcombs with flat spectral profiles provide the high signal-to-noise ratio and are in high demand for wavelength division multiplexing(WDM)-based applications,particularly in future high-capacity communication and parallel optical computing.Here,we present two solutions to generate local relatively flat spectral profiles.One microcavity with ultra-flat integrated dispersion is pumped to generate one relatively flat single soliton source spanning over 150 nm.Besides,one extraordinary soliton crystal with single vacancy demonstrates the local relatively flat microcomb lines when the inner soliton spacings are slightly irregular.Our work paves a new way for soliton-based applications owing to the relatively flat spectral characteristics.

The Impact of Climate Change on Country’s Fragility Assessment

The damage costs of climate change have the potential to cause the breakdown of governmental structures. The paper focuses on how climate change impacts the state’s fragility and how the government should intervene. The paper chooses temperature and rainfall as climate change indicators and establishes a comprehensive evaluating model. The weighting method of the model is determined by combining coefficient of variation method and improved entropy method. The model will output the objective comprehensive evaluation of state’s fragility. The state’s fragilities are quantitatively divided into three levels consisting of the fragile, the vulnerable and the stable in the model. For validation, this paper selects six representative countries and analyzes the degree and the approach of climate change’s impacts on state’s fragility. The fragile values by the model are consistent with the situation in these countries. The state’s fragilities are also predicted by back propagation (BP) neural network. This paper analyzes the impacts of human interventions on improving state’s fragility. The results indicate that the paper could provide reasonable suggestions for the government in the aspects of when and how to take what kind of interventions to improve state’s fragility.

多系统萎缩患者睡眠质量与焦虑、抑郁及精神病性症状相关性研究

目的:探讨多系统萎缩(multiple system atrophy,MSA)患者睡眠质量与焦虑、抑郁及精神病性症状的相关性。方法:选取185例MSA患者,按照匹兹堡睡眠质量指数量表(pittsburgh sleep quality index,PSQI)评分分为MSA伴睡眠障碍组(MSA patients with sleep disorders,MSA-SD组,PSQI>5分)和MSA不伴睡眠障碍组(MSA patients without sleep disorders,MSA-NSD组,PSQI≤5分)。采用简易智能状态检查量表(mini-mental state examination,MMSE)、额叶功能评定量表(frontal Assessment Battery, FAB)、汉密尔顿焦虑量表(hamilton Anxiety Scale,HAMA)、汉密尔顿抑郁量表(hamilton Depression Scale,HAMD)、神经精神量表(neuropsychiatric Inventory, NPI),轻度行为障碍清单(mild Behavioral Impairment Checklist, MBI-C)分别评估患者的整体认知功能、执行功能、焦虑和抑郁情绪以及精神行为状况,分析MSA患者睡眠质量与认知功能、焦虑和抑郁情绪及异常精神行为的相关性。结果:MSA患者睡眠障碍发生率为48.11%,MSA合并睡眠障碍者的整体认知功能、执行功能比不合并睡眠障碍者差,焦虑和抑郁情绪、精神行为症状比不合并睡眠障碍者严重。单因素分析结果显示,PSQI总评分与年龄、MMSE、FAB均无显著关联,而与NPI总评分、HAMA评分、HAMD、MBI评分呈正相关。多重线性回归分析结果表明,抑郁和异常精神行为是MSA相关睡眠障碍的独立危险因素。结论:睡眠质量下降、焦虑和抑郁、精神行为异常是MSA患者常见的非运动症状,患者的抑郁情绪及精神病性症状是影响其睡眠质量的重要因素。

Structural design for electrocatalytic water splitting to realize industrial-scale deployment: Strategies, advances, and perspectives

The green hydrogen generation powered by renewable electricity promises the potential decarbonization of the hard-to-abate sector and is essential for the fulfillment of the Paris Agreement that attempts to limit the global average temperature rise in the range of 1.5–2.0 ℃ above the pre-industrial level by the end of this century. Tremendous efforts have been devoted to the optimization of the electrocatalytic performance of the catalysts under industrial-relevant current densities via rational structure design,which induces a preferential electron distribution that favors the adsorption/desorption behavior of the key intermediates, thus accelerating the reaction kinetics. In this review, a brief introduction of the current energy status will be first presented to necessitate the importance of green hydrogen.Followed by the basic concepts and fundamental understanding of the reaction mechanisms, we present efficient strategies for the enhancement of the electrocatalytic performance of the catalysts to meet the rigorous requirement under industrial conditions and the in-depth understanding behind the reinforcement will be briefly discussed next. Then the recent advances regarding the rational design of electrocatalysts operating at an industrial scale will be summarized. Finally, the challenges and perspectives in this thriving field will be proposed from our point of view.

Comparative studies on leaf epidermal micromorphology and mesophyll structure of Elaeagnus angustifolia L.in two different regions of desert habitat

In order to obtain qualitative and quantitative characteristics of leaf epidermal micromorphology and mesophyll structure to evaluate the responses ofElaeagnus angustifolia L. to different environmental factors, epidermal micromorphology was observed by scanning electron microscopy （SEM）, and mesophyll structure was studied by light microscopy （LM） and transmission electron microscopy （TEM）. Materials were selected from Linze County, Gansu Province （material A） and Qitai County, Xinjiang Uygur Autonomous Region （material B） of China. Results show that lamina thickness was higher in material A, with one layer of epidermal cells in both adaxial and abaxial surfaces, and epidermal cell radial length was significantly longer in the adaxial surface. E. angustifolia leaves are typically bifacial, with a higher ratio of palisade to spongy tissue in material A. The thickness of trichome layer of epidermis was thicker in material A. In contrast, cell wall and cuticular wax of the epidermal cells were thinner in material A than in material B. Chloroplast ultrastructure was different with the approximate spherical chloroplast containing numerous starch grains and osmiophilic granules in ma- terial A, while only the spindly chloroplast contained starch grains in material B. Multiple layers of peltate or stel- late-peltate trichomes occupied both leaf surfaces in material A and the abaxial surface in material B, while the adaxial surface of material B contained few trichomes. Stomata were not observed on the leaf surfaces in materials A and B by SEM because of trichome obstruction. Our results indicate that the leaf structure of E. angustifolia is closely correlated with environmental factors, and the combination of leaf epidermal micromorphology and mesophyll structure afford re- sistance to environmental stress.

大学通识课“实用化学实验”课程的教学探索与实践

“实用化学实验”课程是依托国家级化学化工国家级实验教学示范中心(天津大学)平台,面向全校本科生开设的化学实验类通识教育课程。该课程内容为趣味性强、难度适中且贴近生活的实验项目;实验报告电子化,不拘泥于形式,充分发挥学生的创意,完成形式多样、多彩的报告;采用自编讲义,将劳动教育贯穿整个授课过程,培养学生的劳动品质。一经开课,深受学生喜爱,并获评校级优秀项目,使得通识教育的效果也更上一个台阶。

Characteristics of oceanic mesoscale variabilities associated with the inverse kinetic energy cascade

Oceanic geostrophic turbulence theory predicts significant inverse kinetic energy (KE) cascades at scales larger than the energy injection wavelength. However,the characteristics of the mesoscale variabilities associated with the inverse KE cascade in the real oceans have not been clear enough up to now. To further examine this problem,we analyzed the spectral characteristics of the oceanic mesoscale motions over the scales of inverse KE cascades based on high-resolution gridded altimeter data. The applicability of the quasigeostrophic (QG) turbulence theory and the surface quasigeostrophic (SQG) turbulence theory in real oceans is further explored. The results show that the sea surface height (SSH) spectral slope is linearly related to the eddy-kinetic-energy (EKE) level with a high correlation coefficient value of 0.67. The findings also suggest that the QG turbulence theory is an appropriate dynamic framework at the edge of high-EKE regions and that the SQG theory is more suitable in tropical regions and low-EKE regions at mid-high latitudes. New anisotropic characteristics of the inverse KE cascade are also provided. These results indicate that the along-track spectrum used by previous studies cannot reveal the dynamics of the mesoscale variabilities well.

The Realization and Working Conditions of Memristor Based on Multisim

An equivalent circuit is realized using Multisim software by transforming a kind of circuit element according to Mapping principle and circuit theory. The effects of every parameter on the equivalent circuit are analyzed and the working conditions of the equivalent circuit are concluded by simulation.

Research Progress of Cognitive Impairment in Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a kind of serious mental disorder that occurs after severe traumatic events. It is characterized by severe emotional and memory damage. This paper reviews the relevant research literature on PTSD at home and abroad in recent years, and reviews the mechanism of cognitive impairment in mental trauma to reveal the functional mechanism of cognitive impairment in post-traumatic stress disorder, in order to provide reference for future research.

Influence of Atmospheric Particulate Matter on Ozone in Nanjing,China:Observational Study and Mechanistic Analysis

Particulate matter with diameters of 2.5 μm or smaller(PM_(2.5)) and ozone(O_3) are major pollutants in the urban atmosphere. PM_(2.5) can affect O_3 by altering the photolysis rate and heterogeneous reactions. However, these two processes and their relative importance remain uncertain. In this paper, with Nanjing in China as the target city, we investigate the characteristics and mechanism of interactions between particles and O_3 based on ground observations and numerical modeling.In 2008, the average concentrations of PM_(2.5) and O_3 at Caochangmen station are 64.6 ± 47.4 μg m^(-3) and 24.6 ± 22.8 ppb,respectively, while at Pukou station they are 94.1 ± 63.4 μg m^(-3) and 16.9 ± 14.9 ppb. The correlation coefficient between PM_(2.5) and O_3 is -0.46. In order to understand the reaction between PM_(2.5) and O_3, we construct a box model, in which an aerosol optical property model, ultraviolet radiation model, gas phase chemistry model, and heterogeneous chemistry model,are coupled. The model is employed to investigate the relative contribution of the aforementioned two processes, which vary under different particle concentrations, scattering capability and VOCs/NOxratios(VOCs: volatile organic compounds;NOx: nitric oxide and nitrogen dioxide). Generally, photolysis rate effect can cause a greater O_3 reduction when the particle concentrations are higher, while heterogeneous reactions dominate O_3 reduction with low-level particle concentrations.Moreover, in typical VOC-sensitive regions, O_3 can even be increased by heterogeneous reactions. In Nanjing, both processes lead to O_3 reduction, and photolysis rate effect is dominant. Our study underscores the importance of photolysis rate effect and heterogeneous reactions for O_3, and such interaction processes should be fully considered in future atmospheric chemistry modeling.

Research on Ecological Water Cycle and Purification in Rural Landscape——Take Zhangjia Village Ecological Wastewater Treatment Project in Henan Province as an Example

Rural landscape is not only a natural landscape,but also a cultural landscape.The improvement of rural environment in Lushi County is carried out under the background of“Building Beautiful Villages”.Through the plan of environmental improvement,the appearance of villages in rural areas will be significantly improved,and the gap between urban and rural areas will be shortened.This research addresses the problems of scarce water resources,imperfect rainwater collection facilities,and increased environmental pollution in rural areas,and explores a flexible,effective,and integrated landscape ecological water treatment system that integrates with natural ecosystems.The practice has shown that the flexible combination of different technical measures according to local conditions and the construction of ecological water self-circulation and self-purification systems can reduce maintenance costs and achieve sustainable landscape.The virtuous cycle of the revetment’s micro-ecology greatly improves the environmental carrying capacity of the landscape.Reasonable water management system is more flexible in dealing with unexpected problems.The thesis proposes landscape design strategies for water circulation and water purification in rural areas,and applies them to actual design cases.It attempts to introduce a combined treatment system to achieve a more diverse landscape concept and further explore the healthy and sustainable development of rural water environment.

KIF23在结直肠癌中的表达及其临床意义

目的:探讨KIF23在结直肠癌中的表达及其临床意义。方法:分析TCGA数据库中KIF23 mRNA在结直肠癌中的表达。分析2010年2月至2013年2月于河南大学淮河医院行手术治疗的116例结直肠癌组织标本及患者临床病理资料,通过免疫组织化学法检测KIF23在结直肠癌组织中的表达,分析其与临床病理参数及预后的相关性。结果:TCGA数据库分析结果表明,癌组织中KIF23 mRNA表达水平增高(P<0.05)。免疫组织化学法检测结果提示61.2%(71/116)的结直肠癌组织中KIF23蛋白表达阳性。KIF23蛋白表达与T、N、M及TNM分期有相关性(P<0.05)。Kaplan-Meier生存分析提示与低表达KIF23相比,高表达KIF23患者的总生存时间、无复发生存时间显著缩短(P<0.05)。Cox回归分析提示KIF23是影响结直肠癌患者预后的独立危险因素。结论:KIF23在结直肠癌中高表达,可能成为预测结直肠癌患者发生发展及预后的分子标记物。

Single-molecule optoelectronic devices:physical mechanism and beyond

Single-molecule devices not only promise to provide an alternative strategy to break through the miniaturization and functionalization bottlenecks faced by traditional semiconductor devices,but also provide a reliable platform for exploration of the intrinsic properties of matters at the single-molecule level.Because the regulation of the electrical properties of single-molecule devices will be a key factor in enabling further advances in the development of molecular electronics,it is necessary to clarify the interactions between the charge transport occurring in the device and the external fields,particularly the optical field.This review mainly introduces the optoelectronic effects that are involved in single-molecule devices,including photoisomerization switching,photoconductance,plasmon-induced excitation,photovoltaic effect,and electroluminescence.We also summarize the optoelectronic mechanisms of single-molecule devices,with particular emphasis on the photoisomerization,photoexcitation,and photo-assisted tunneling processes.Finally,we focus the discussion on the opportunities and challenges arising in the single-molecule optoelectronics field and propose further possible breakthroughs.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing.Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes,which respectively exhibit pro-inflammatory or anti-inflammatory functions.Therefore,modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing.Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity.In this study,we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures.The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages,thereby accelerating diabetic fracture healing.We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway.Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

Nano-calcium silicate mineralized fish scale scaffolds for enhancing tendon-bone healing

Tendon-bone healing is essential for an effective rotator cuff tendon repair surgery,however,this remains a significant challenge due to the lack of biomaterials with high strength and bioactivity.Inspired by the high-performance exoskeleton of natural organisms,we set out to apply natural fish scale(FS)modified by calcium silicate nanoparticles(CS NPs)as a new biomaterial(CS-FS)to overcome the challenge.Benefit from its“Bouligand”microstructure,such FS-based scaffold maintained excellent tensile strength(125.05 MPa)and toughness(14.16 MJ/m^(3)),which are 1.93 and 2.72 times that of natural tendon respectively,allowing it to well meet the requirements for rotator cuff tendon repair.Additionally,CS-FS showed diverse bioactivities by stimulating the differentiation and phenotypic maintenance of multiple types of cells participated into the composition of tendon-bone junction,(e.g.bone marrow mesenchymal stem cells(BMSCs),chondrocyte,and tendon stem/progenitor cells(TSPCs)).In both rat and rabbit rotator cuff tear(RCT)models,CS-FS played a key role in the tendon-bone interface regeneration and biomechanical function,which may be achieved by activating BMP-2/Smad/Runx2 pathway in BMSCs.Therefore,natural fish scale-based biomaterials are the promising candidate for clinical tendon repair due to their outstanding strength and bioactivity.

An improved optical flow method to estimate Arctic sea ice velocity(winter 2014-2016)

Sea ice velocity impacts the distribution of sea ice,and the flux of exported sea ice through the Fram Strait increases with increasing ice velocity.Therefore,improving the accuracy of estimates of the sea ice velocity is important.We introduce a pyramid algorithm into the Horn-Schunck optical flow(HS-OF)method(to develop the PHS-OF method).Before calculating the sea ice velocity,we generate multilayer pyramid images from an original brightness temperature image.Then,the sea ice velocity of the pyramid layer is calculated,and the ice velocity in the original image is calculated by layer iteration.Winter Arctic sea ice velocities from 2014 to 2016 are obtained and used to discuss the accuracy of the HS-OF method and PHS-OF(specifically the 2-layer PHS-OF(2 LPHS-OF)and 4-layer PHS-OF(4 LPHS-OF))methods.The results prove that the PHS-OF method indeed improves the accuracy of sea ice velocity estimates,and the 2 LPHS-OF scheme is more appropriate for estimating ice velocity.The error is smaller for the 2 LPHS-OF velocity estimates than values from the Ocean and Sea Ice Satellite Application Facility and the Copernicus Marine Environment Monitoring Service,and estimates of changes in velocity by the 2 LPHS-OF method are consistent with those from the National Snow and Ice Data Center.Sea ice undergoes two main motion patterns,i.e.,transpolar drift and the Beaufort Gyre.In addition,cyclonic and anticyclonic ice drift occurred during winter 2016.Variations in sea ice velocity are related to the open water area,sea ice retreat time and length of the open water season.

Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

In August 2018,a remarkable polynya was observed off the north coast of Greenland,a perennial ice zone where thick sea ice cover persists.In order to investigate the formation process of this polynya,satellite observations,a coupled iceocean model,ocean profiling data,and atmosphere reanalysis data were applied.We found that the thinnest sea ice cover in August since 1978(mean value of 1.1 m,compared to the average value of 2.8 m during 1978-2017) and the modest southerly wind caused by a positive North Atlantic Oscillation(mean value of 0.82,compared to the climatological value of-0.02) were responsible for the formation and maintenance of this polynya.The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind.Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

Demonstration of superadiabatic population transfer in superconducting qubit

We implemented the superadiabatic population transfer within the nonadiabatic regime in a two-level superconducting qubit system. To realize the superadiabatic procedure, we added an additional term in the Hamiltonian, introducing an auxiliary counter-diabatic field to cancel the nonadiabatic contribution in the evolution. Based on the superadiabatic procedure, we further demonstrated quantum Phase and NOT gates. These operations, which possess both of the fast and robust features, are promising for quantum information processing.

Frailty and Anticoagulant Therapy in Patients Aged 65 Years or Older with Atrial Fibrillation

Background:Elderly adults with atrial fi brillation(AF)are at increased risk of frailty and thromboembolic complications.However,studies on the prevalence of frailty in AF patients and data on the relationship between frailty and the use of anticoagulants are limited.Methods:We conducted a cross-sectional study involving 500 participants.Patients aged 65 years or older were consecutively selected from the Chinese Atrial Fibrillation Registry study.The patient’s frailty status was assessed with use of the Canadian Study of Health and Aging Clinical Frailty Scale.We assessed the prevalence of and factors associated with frailty,and how frailty affects anticoagulant therapy.Results:In 500 elderly adults with AF(age 75.2±6.7 years;51.6%female),201 patients(40.2%)were frail.The prevalence of frailty was higher in females(P=0.002)and increased with age and CHA 2 DS 2-VASc score(P for trend less than 0.001 for both).The factors associated with frailty were a history of heart failure(odds ratio[OR]2.40,95%confi dence interval[CI]1.39–4.14),female sex(OR 2.09,95%CI 1.27–3.43),and advanced age(OR 1.13,95%CI 1.09–1.17).Frail patients were signifi cantly less likely to have ever been prescribed anticoagulants compared with nonfrail patients(81.7 vs.54.9%,P<0.001).Conclusions:Frailty is prevalent in elderly adults with AF,especially in females,those of advanced age,and those with heart failure.Frailty status has a signifi cant impact on prescription of anticoagulants for high-risk AF patients.

Demonstration of quantum permutation parity determine algorithm in a superconducting qutrit

A quantum algorithm provides a new way in solving certain computing problems and usually faster than classical algorithms. Here we report an implementation of a quantum algorithm to determine the parity of permutation in a single three-dimensional（3D） superconducting transmon qutrit system. The experiment shows the capacity to speed up in a qutrit,which can also be extended to a multi-level system for solving high-dimensional permutation parity determination problem.