MWCNT Doped Reverse-Mode Polymer Network Liquid Crystals with Frequency Response Property

Polymer-liquid crystals(PLCs)are common materials for smart windows.However,PLC smart windows usually require high driving voltage to maintain transparency.We synthesized a novel PLC smart film by doping multi-wall carbon nanotubes(MWCNTs)into a reverse-mode polymer network liquid crystal(R-PNLC).

Milli-Joule pulses post-compressed from 14 ps to 475 fs in bulk-material multi-pass cell based on cylindrical vector beam

A cylindrical vector beam is utilized to enhance the energy scale of the pulse post-compressed in a bulk-material Herriott multi-pass cell(MPC).The method proposed here enables,for the first time to the best of our knowledge,pulse compression from 14 ps down to 475 fs with throughput energy beyond 1 mJ,corresponding to a compression ratio of 30,which is the highest pulse energy and compression ratio in single-stage bulk-material MPCs.Furthermore,we demonstrate the characteristic of the vector polarization beam is preserved in the MPC.

Fe1+yTexSe1-x:A Delicate and Tunable Majorana Material

We report the observation for the pz electron band and the band inversion in Fe1+yTexSe1-xwith angleresolved photoemission spectroscopy. Furthermore, we found that excess Fe(y>0) inhibits the topological band inversion in Fe1+yTexSe1-x,which explains the absence of Majorana zero modes in previous reports for Fe1+yTexSe1-xwith excess Fe. Based on our analysis of different amounts of Te doping and excess Fe, we propose a delicate topological phase in this material. Thanks to this delicate phase, one may be able to tune the topological transition via applying lattice strain or carrier doping.

MiR-520f-3p inhibits epithelial-mesenchymal transition of colorectal cancer cells by targeting Yes-associated protein 1

Background:Colorectal cancer(CRC)is one of the most common malignancies.Early diagnosis is the key to effective treatment of CRC.Since microRNAs(miRNAs)can be used as biomarkers of CRC,the objective of this work was to examine the effect of miR-520f-3p,which targets YAP1(Yes-associated protein 1),on the ability of CRC cells to proliferate,invade,migrate,and undergo epithelial-mesenchymal transition(EMT).Methods:A miR-520f-3p mimic was used to overexpress miR-520f-3p in HT29 cells.To establish the tumor-bearing mouse model,transfected HT29 cells were subcutaneously implanted into BALB/c-nu nude mice,and YAP1 and miR-520f-3p levels were determined using qRT‒PCR.The viability,invasion ability,and migration ability of cells were evaluated by CCK-8,Transwell,and wound healing assays.Apoptosis was detected by flow cytometry and TUNEL assays.The regulatory link between miR-520f-3p and the YAP1 gene was examined by dual-luciferase reporter assay.Tumor tissues with positive Ki-67 expression were identified by immunohistochemistry.Vimentin,E-cadherin,and YAP1 expression were evaluated by western blotting.Results:MiR-520f-3p overexpression could inhibit proliferation,invasion,migration,and EMT and induce apoptosis in HT29 cells.YAP1 was found as a target of miR-520f-3p.The inhibitory effects of miR-520f-3p on proliferation,invasion,migration,and EMT may be reversed by overexpressing YAP1.In tumor-bearing mice,miR-520f-3p overexpression reduced the Ki-67 level,increased apoptosis,and prevented tumor development and spread.Conclusion:By targeting YAP1,miR-520f-3p may be capable of suppressing CRC cell proliferation,invasion,migration,and EMT,providing a novel therapeutic target for the disease.

Distinct behavior of electronic structure under uniaxial strain in BaFe_(2)As_(2)

We report a study of the electronic structure of BaFe_(2)As_(2) under uniaxial strains using angle-resolved photoemission spectroscopy and transport measurements. Two electron bands at the MY point, with an energy splitting of 50 meV in the strain-free sample, shift downward and merge into each other under a large uniaxial strain, while three hole bands at theГ point shift downward together. However, we also observed an enhancement of the resistance anisotropy under uniaxial strains by electrical transport measurements, implying that the applied strains strengthen the electronic nematic order in BaFe_(2)As_(2). These observations suggest that the splitting of these two electron bands at the MY point is not caused by the nematic order in BaFe_(2)As_(2).

Thermal Shock-Activated Spontaneous Growing of Nanosheets for Overall Water Splitting

Nanomaterials based on nickel foam(NF) have been widely applied in energy conversion and storage field.Traditional synthesis methods such as hydrothermal method which is dangerous and high cost limited the scalable developments.Herein,we report a fast,simple,and low-cost synthesis method of nanomaterials based on NF by Joule-heating and water soaking treatment.Thin carbon-coated CoS on NF(NF-C/CoS) was synthesized by Joule-heating for a few seconds with rapid cooling.And then,NF-C/CoS/NiOOH with core-shell heterostructure was fabricated by soaking treatment of NF-C/CoS in water on which NiOOH nanosheets grew spontaneously.The formation mechanism is proposed that the coordination complex precursor converts into C/CoS on NF driven by Joule-heating,and the nickel on the surface of NF is activated to form metastable nickel simultaneously.The metastable nickel reacting with water leads to the formation of NiOOH,and the induction of CoS makes NiOOH grow continuously.This synthesis technology provides a new route to manufacture NF-based nanostructures,and the as-fabricated NF-C/CoS/NiOOH exhibits great potential as electrocatalyst for oxygen evolution reaction and hydrogen evolution reaction.

Discrimination of dislocations in 4H-SiC by inclination angles of molten-alkali etched pits

Discrimination of dislocations is critical to the statistics of dislocation densities in 4H silicon carbide(4H-SiC),which are routinely used to evaluate the quality of 4H-SiC single crystals and homoepitaxial layers.In this work,we show that the inclination angles of the etch pits of molten-alkali etched 4H-SiC can be adopted to discriminate threading screw dislocations(TSDs),threading edge dislocations(TEDs)and basal plane dislocations(BPDs)in 4H-SiC.In n-type 4H-SiC,the inclination angles of the etch pits of TSDs,TEDs and BPDs in molten-alkali etched 4H-SiC are in the ranges of 27°−35°,8°−15°and 2°−4°,respectively.In semi-insulating 4H-SiC,the inclination angles of the etch pits of TSDs and TEDs are in the ranges of 31°−34°and 21°−24°,respectively.The inclination angles of dislocation-related etch pits are independent of the etching duration,which facilitates the discrimination and statistic of dislocations in 4H-SiC.More significantly,the inclination angle of a threading mixed dislocations(TMDs)is found to consist of characteristic angles of both TEDs and TSDs.This enables to distinguish TMDs from TSDs in 4H-SiC.

Edge-Cloud Collaborative Optimization Scheduling with Micro-Service Architecture

The architecture of edge-cloud cooperation is proposed as a compromising solution that combines the advantage of MEC and central cloud. In this paper we investigated the problem of how to reduce the average delay of MEC application by collaborative task scheduling. The collaborative task scheduling is modeled as a constrained shortest path problem over an acyclic graph. By characterizing the optimal solution, the constrained optimization problem is simplified according to one-climb theory and enumeration algorithm. Generally, the edge-cloud collaborative task scheduling scheme performance better than independent scheme in reducing average delay. In heavy workload scenario, high blocking probability and retransmission delay at MEC is the key factor for average delay. Hence, more task executed on central cloud with abundant resource is the optimal scheme. Otherwise, transmission delay is inevitable compared with execution delay. MEC configured with higher priority and deployed close to terminals obtain more performance gain.

Electronic Structure of the Weak Topological Insulator Candidate Zintl Ba_(3)Cd_(2)Sb_(4)

One of the greatest triumph of condensed matter physics in the past ten years is the classification of materials by the principle of topology.The existence of topological protected dissipationless surface state makes topological insulators great potential for applications and hotly studied.However,compared with the prosperity of strong topological insulators,theoretical predicted candidate materials and experimental confirmation of weak topological insulators(WTIs) are both extremely rare.By combining systematic first-principles calculation and angle-resolved photoemission spectroscopy measurements,we have studied the electronic structure of the dark surface of the WTI candidate Zintl Ba_(3)Cd_(2)Sb_(4)and another related material Ba_(3)Cd_(2)As_(4).The existence of two Dirac surface states on specific side surfaces predicted by theoretical calculations and the observed two band inversions in the Brillouin zone give strong evidence to prove that the Ba_(3)Cd_(2)Sb_(4)is a WTI.The spectroscopic characterization of this Zintl Ba_(3)Cd_(2)N_(4)(N = As and Sb) family materials will facilitate applications of their novel topological properties.

Effect of Ni,Fe and Fe-Ni alloy catalysts on the synthesis of metal contained carbon nano-onions and studies of their electrochemical hydrogen storage properties

Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy catalysts.Comparative and systematic studies have been carried out on the morphology,structural characteristics and graphitic crystallinity of these CNOs products.Furthermore,the electrochemical hydrogen storage properties of three types of CNOs have been investigated.Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g,coiTesponding to a hydrogen storage of 1.42%.This comparison study shows the advantages of each catalyst in the growth of CNOs.enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.

Influences of fisheries management measures on biological characteristics of threadfin bream(Nemipterus virgatus)in the Beibu Gulf,South China Sea

Long-term variations in population structure,growth,mortality,length at median sexual maturity,and exploitation rate of threadfin bream(Nemipterus virgatus)are reported based on bottom trawl survey data collected during 1960-2012 in the Beibu Gulf,South China Sea.Laboratory-based analyses were conducted on 16791 individuals collected quarterly in eight different sampling years.Average body length,estimated asymptotic length,and percentage of large individuals have decreased significantly with the growth of marine catch and fishing power,indicating individual miniaturization of this fish species.Estimated exploitation rates indicate that the N.virgatus stock in the Beibu Gulf was moderately exploited in 1960 and 1962 and overexploited after 1992.This stock was taking a good turn in status in 2012,with the lowest exploitation rate since 1992 and ceased downward trend in length indexes.These results suggest that management measures to reduce fishing pressure may have a positive influence on the biological characteristics of this commercial fish species.Biological characteristics of most commercial fish species have phenotypic plasticity and might change over years in response to fisheries management.Therefore,attentions should be paid on variations in fish biological characteristics,when evaluating the effectiveness of current measures to control the total catch for all fisheries.

Advanced liquid crystal-based switchable optical devices for light protection applications:principles and strategies

With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.

Sub-diffraction-limit cell imaging using a super-resolution microscope with simplified pulse synchronization

Stimulated emission depletion(STED) microscope is one of the most prominent super-resolution bio-imaging instruments, which holds great promise for ultrahigh-resolution imaging of cells. To construct a STED microscope, it is challenging to realize temporal synchronization between the excitation pulses and the depletion pulses. In this study, we present a simple and low-cost method to achieve pulse synchronization by using a condensed fluorescent dye as a depletion indicator. By using this method, almost all the confocal microscopes can be upgraded to a STED system without losing its original functions. After the pulse synchronization,our STED system achieved sub-100-nm resolution for fluorescent nanospheres and single-cell imaging.

Cu nanoparticle-decorated two-dimensional carbon nanosheets with superior photothermal conversion efficiency of 65 % for highly efficient disinfection under near-infrared light

Low photothermal conversion efficiency restricts the antibacterial application of photothermal materials.In this work,two-dimensional carbon nanosheets(2D C)were prepared and decorated with Cu nanoparticles(2D C/Cu)by using a simple soluble salt template method combined with ultrasonic exfoliation.The photothermal conversion efficiency of 2 D C/Cu system can be optimized by changing the content of Cu nanoparticles,where the 2D C/Cu2 showed the best photothermal conversion efficiency(á)of 65.05%under 808 nm near-infrared light irradiation.In addition,the photothermal performance can affect the release behavior of Cu ions.This superior photothermal property combined with released Cu ions can endow this 2D hybrid material with highly efficient antibacterial efficacy of 99.97%±0.01%,99.96%±0.01%,99.97%±0.01%against Escherichia coli,Staphylococcus aureus,and methicillin-resistant Staphylococcus aureus,respectively,because of the synergetic effect of photothermy and ion release.In addition,this 2D hybrid system exhibited good cytocompatibility.Hence,this study provides a novel strategy to enhance the photothermal performance of 2D materials and thus will be beneficial for development of antibiotics-free antibacterial materials with safe and highly efficient bactericidal activity.

Bilayer hydrogel dressing with lysozymeenhanced photothermal therapy for biofilm eradication and accelerated chronic wound repair

Biofilms are closely associated with the tough healing and dysfunctional inflammation of chronic wounds.Photothermal therapy(PTT)emerged as a suitable alternative which could destroy the structure of biofilms with local physical heat.However,the efficacy of PTT is limited because the excessive hyperthermia could damage surrounding tissues.Besides,the difficult reserve and delivery of photothermal agents makes PTT hard to eradicate biofilms as expectation.Herein,we present a GelMA-EGF/Gelatin-MPDA-LZM bilayer hydrogel dressing to perform lysozyme-enhanced PTT for biofilms eradication and a further acceleration to the repair of chronic wounds.Gelatin was used as inner layer hydrogel to reserve lysozyme(LZM)loaded mesoporous polydopamine(MPDA)(MPDA-LZM)nanoparticles,which could rapidly liquefy while temperature rising so as to achieve a bulk release of nanoparticles.MPDA-LZM nanoparticles serve as photothermal agents with antibacterial capability,could deeply penetrate and destroy biofilms.In addition,the outer layer hydrogel consisted of gelatin methacryloyl(GelMA)and epidermal growth factor(EGF)promoted wound healing and tissue regeneration.It displayed remarkable efficacy on alleviating infection and accelerating wound healing in vivo.Overall,the innovative therapeutic strategy we came up with has significant effect on biofilms eradication and shows promising application in promoting the repair of clinical chronic wounds.

腹腔镜结直肠癌NOSES术中左结肠动脉的外科解剖与保留技巧

目的观察腹腔镜结直肠癌经自然腔道取标本手术(NOSES)中左结肠动脉(LCA)的外科解剖,探讨保留LCA的手术技巧及临床疗效。方法回顾性分析2017年1月至2021年12月于四川省肿瘤医院施行腹腔镜下保留LCA的结直肠癌NOSES手术85例患者的临床资料,其中54例术中对LCA的外科解剖进行了观察与记录,结合手术录像分析LCA的外科走行与解剖分型,探讨保留LCA的操作技巧和临床效果。结果所有病例LCA均从肠系膜下动脉(IMA)左侧发出,LCA发出处至IMA根部的平均距离为(3.5±1.1)cm;75.9%(41/54)病例LCA向外走行时自肠系膜下静脉(IMV)前方与其相交,24.1%(13/54)自IMV后方与其相交;LCA自IMA单独发出者(Ⅰ型)23例(42.6%),LCA与乙状结肠动脉(SA)两支共干者(Ⅱ型)9例(16.7%),LCA与SA、直肠上动脉(SRA)三支共干者(Ⅲ型)19例(35.2%),LCA、SRA与两支或两支以上SA多支共干者(Ⅳ型)3例(5.6%),本组未见LCA缺如病例。85例患者均顺利完成手术,其中2例(2.4%)术后出现了吻合口漏,1例经保守治疗痊愈,1例进行了回肠造瘘手术;无围手术期死亡病例;术后平均住院时间(10.4±3.4)d。结论LCA的外科走行多样,解剖变异复杂;腹腔镜下保留LCA需要较高的手术技巧、精细解剖、耐心操作。腹腔镜结直肠癌术中保留LCA操作与NOSES技术相结合,有望将损伤控制、功能保护、微创治疗的外科理念发挥到极致。

A bottom-up strategy toward metal nano-particles modified graphene nanoplates for fabricating aluminum matrix composites and interface study

To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up strategy for the mass production of metal nanoparticles modified graphene nanoplates(GNPs)was proposed.Cu nanoparticles modified GNPs(Cu-GNPs)and Ni nanoparticles modified GNPs(Ni-GNPs)were fabricated through this method,and then compounded with Al via ball milling technique.The asobtained Ni-GNPs/Al composite showed simultaneously improved strength and toughness compared with unreinforced Al,while the Cu-GNPs/Al composite presented a greater strengthening effect.The microstructure and interface of the two composites were carefully characterized and investigated to reveal the difference.First principle study was also adopted to explore the binding energy of different interface structures.This study could provide new insights into the fabrication of GNPs and the control of interface in GNPs/Al composites.

Exosomes with low miR-34c-3p expression promote invasion and migration of non-small cell lung cancer by upregulating integrinα2β1

Exosomes play critical roles in regulating various physiological and pathological processes,including immune stimulation,immune suppression,cardiovascular diseases,and cancers.Recent studies show that exosomes that transport specific microRNAs(miRNAs)are involved in tumor development.However,the molecular mechanism by which tumor invasion and migration are regulated by exosomes from non-small cell lung cancer(NSCLC)is not well understood.Here,we show that exosomes shuttling low levels of miR-34c-3p are involved in NSCLC progression.Our results showed that exosomes derived from NSCLC cells carrying low levels of miR-34c-3p could be transported into the cytoplasm of NSCLC cells and accelerate NSCLC invasion and migration by upregulating integrinα2β1.A luciferase assay revealed that integrinα2β1 was the direct target of miR-34c-3p,and overexpression of integrinα2β1 could promote the invasion and migration of NSCLC cells.The analysis of exosomes derived from clinical serum samples indicated that the expression of miR-34c-3p was significantly downregulated in exosomes from NSCLC patients compared with that of normal controls.A549-derived exosomes promoted NSCLC cells lung metastases in vivo.Exosomes shuttling low levels of miR-34c-3p were associated with the progression of NSCLC in vitro and in vivo.Our data demonstrate that exosomes shuttling low levels of miR-34c-3p can accelerate the invasion and migration of NSCLC by upregulating integrinα2β1.MiR-34c-3p can be a diagnostic and prognostic marker for NSCLC.High expression of integrinα2β1 is positively related to the migration and metastasis of NSCLC cells.

Simultaneously optimizing pore morphology and enhancing mechanical properties of Al-Si alloy composite foams by graphene nanosheets

The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials.The conventional methods on refining pore morphology are mainly focused on the optimization of fabrication techniques,however,they are usually inconvenient and complicated.Recently,incorporating nano reinforcement is considered to be a suitable way to fabricate metallic composite foams accompanied by optimized pore morphology and enhanced mechanical properties.In this work,through a facile and rapid powder metallurgy foaming method,the aluminum-silicon(Al-Si)alloy composite foams reinforced by graphene nanosheets(GNSs)are successfully fabricated.The microstructure analyses reveal that,for the Al-Si alloy foams incorporating the GNSs(GNSs/Al-Si composite foams),the pore size is transformed to be smaller,the pore size distributions become more homogeneous and the pore shape is also refined to a regular and roundish state.Meanwhile,the shape of Si precipitates is found transforming from an irregular long strip(length of~20μm,width of~5μm)to a fine particle state(diameter of~5μm).Moreover,the compressive testing results show that,the 0.4wt%GNSs/Al-Si composite foams own the optimal compression stress of 11.7±0.5 MPa,plateau stress of 10.0±1.0 MPa and energy absorption capacity of 6.8±0.7 MJ/m^(3),which have improvement of 58.1%,53.8%and 51.1%in comparison with the Al-Si alloy foams counterpart,respectively.The present findings may pave a new way for developing new generation of metallic composite foams that with stable microstructure and excellent mechanical performance.

Superresolution imaging of telomeres with continuous wave stimulated emission depletion (STED) microscope

The significant role of telomeres in cells has attracted much attention since they were discovered.Fluorescence imaging is an effective method to study subcellular structures like telomeres.However,the diffraction limit of traditional optical microscope hampers further investigation on them.Recent progress on superresolution fluorescence microscopy has broken this limit.In this work,we used stimulated emission depletion(STED) microscope to observe fluorescence-labeled telomeres in interphase cell nuclei.The results showed that the size of fluorescent puncta representing telomeres under the STED microscope was much smaller than that under the confocal microscope.Two adjacent telomeres were clearly separated via STED imaging,which could hardly be discriminated by confocal microscopy due to the diffraction limit.We conclude that STED microscope is a more powerful tool that enable us to obtain detailed information about telomeres.