Development of track geometry inspection equipment for high-speed comprehensive inspection train in China

Purpose–This study aims to analyze the development direction of track geometry inspection equipment for high-speed comprehensive inspection train in China.Design/methodology/approach–The development of track geometry inspection equipment for highspeed comprehensive inspection train in China in the past 20 years can be divided into 3 stages.Track geometry inspection equipment 1.0 is the stage of analog signal.At the stage 1.0,the first priority is to meet the China’s railways basic needs of pre-operation joint debugging,safety assessment and daily dynamic inspection,maintenance and repair after operation.Track geometry inspection equipment 2.0 is the stage of digital signal.At the stage 2.0,it is important to improve stability and reliability of track geometry inspection equipment by upgrading the hardware sensors and improving software architecture.Track geometry inspection equipment 3.0 is the stage of lightweight.At the stage 3.0,miniaturization,low power consumption,self-running and green economy are co-developing on demand.Findings–The ability of track geometry inspection equipment for high-speed comprehensive inspection train will be expanded.The dynamic inspection of track stiffness changes will be studied under loaded and unloaded conditions in response to the track local settlement,track plate detachment and cushion plate failure.The dynamic measurement method of rail surface slope and vertical curve radius will be proposed,to reveal the changes in railway profile parameters of high-speed railways and the relationship between railway profile,track irregularity and subsidence of subgrade and bridges.The 200 m cut-off wavelength of track regularity will be researched to adapt to the operating speed of 400 km/h.Originality/value–The research can provide new connotations and requirements of track geometry inspection equipment for high-speed comprehensive inspection train in the new railway stage.

猪肉嫩度测定方法对比分析

【目的】改进肌肉嫩度测定方法,达到简单、快速、易于操作,以期适用工业化生产。【方法】以45头杜长大三元杂交猪(DLY)背最长肌为素材,利用嫩度仪和质构仪,研究屠宰后8 h、24 h、48 h、72 h 4个时间点、不同肌纤维走向的冷却肉嫩度,以及72 h熟肉嫩度,对比分析不同时间点、肌纤维走向和不同仪器测定的肌肉剪切力值,建立冷却肉与熟肉间的数学模型。【结果】宰后8~72 h不同肌纤维走向(垂直、斜向)的冷却肉剪切力值变化趋势一致,二者间极显著正相关(p <0.01);宰后24 h冷却肉剪切力值与72 h熟肉剪切力值呈显著线性相关(p <0.05);国产嫩度仪与质构仪测定的肌肉剪切力值极显著正相关,相关系数达0.688 (p <0.01),而且二者间线性关系良好。【结论】生产中24 h排酸后可直接横切取背最长肌,钻取肉样进行剪切力值测定;屠后24 h冷却肉剪切力值可客观反映猪肉嫩度;国产嫩度仪可与质构仪互相替代,进行肌肉嫩度评定。

猪链球菌病的防控综述

猪链球菌病是由多种致病性链球菌感染引起的一种人兽共患传染病,有重要的公共卫生意义,同时也是当今危害养猪业最重要的细菌性疾病之一,其严重制约我国乃至世界养猪业的发展。文章主要对猪链球菌概况、临床症状与病理变化、诊断、治疗和预防进行综述,以期为猪链球菌病的防控提供参考。

Phase transition-induced superstructures ofβ-Sn films with atomic-scale thickness

The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been successfully fabricated via phase transition engineering.However,the understanding of structural phase transition ofβ-Sn(001)thin films is still elusive.Here,we report the direct growth of ultrathinβ-Sn(001)films epitaxially on the highly oriented pyrolytic graphite(HOPG)substrate and the characterization of intricate structural-transition-induced superstructures.The morphology was obtained by using atomic force microscopy(AFM)and low-temperature scanning tunneling microscopy(STM),indicating a structure-related bilayer-by-bilayer growth mode.The ultrathinβ-Sn film was made of multiple domains with various superstructures.Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains.The formation mechanism of these superstructures was further discussed based on the structural phase transition ofβtoα-Sn at the atomic-scale thickness.Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit,but also paves a way to investigate their structure-sensitive topological properties.

Epitaxial growth of antimony nanofilms on HOPG and thermal desorption to control the film thickness

Group-V elemental nanofilms were predicted to exhibit interesting physical properties such as nontrivial topological properties due to their strong spin-orbit coupling,the quantum confinement,and surface effect.It was reported that the ultrathin Sb nanofilms can undergo a series of topological transitions as a function of the film thickness h:from a topological semimetal(h>7.8 nm)to a topological insulator(7.8 nm>h>2.7 nm),then a quantum spin Hall(QSH)phase(2.7 nm>h>1.0 nm)and a topological trivial semiconductor(h<1.0 nm).Here,we report a comprehensive investigation on the epitaxial growth of Sb nanofilms on highly oriented pyrolytic graphite(HOPG)substrate and the controllable thermal desorption to achieve their specific thickness.The morphology,thickness,atomic structure,and thermal-strain effect of the Sb nanofilms were characterized by a combination study of scanning electron microscopy(SEM),atomic force microscopy(AFM),and scanning tunneling microscopy(STM).The realization of Sb nanofilms with specific thickness paves the way for the further exploring their thickness-dependent topological phase transitions and exotic physical properties.

Genetic variants in the 6p21.3 region influence hepatitis B virus clearance and chronic hepatitis B risk in the Han Chinese population

Background and aim:A genome-wide association study has indicated the association of numerous genes in the 6p21.3 region with chronic hepatitis B virus(HBV)infection.In this study,we screened 12 representative single-nucleotide polymorphisms(SNPs)from the 6p21.3 region and investigated their association with the risk of chronic hepatitis B(CHB)to better understand the molecular etiology un-derlying CHB risk in the Han Chinese population.Methods:Between March 2021 and November 2022,we included 183 patients with CHB(case group)and 196 with natural HBV clearance(control group).Allele typing of the selected SNPs was performed using snapshot technology.The correlation between the 12 chosen SNPs and the risk of chronic HBV infection was examined using binary logistic regression analysis.Interacting genes of the variants were identified,and expression quantitative trait loci(eQTL)were analyzed using the 3DSNP database.Results:We validated 12 previously reported CHB susceptibility sites,including rs1419881 of tran-scription factor 19(TCF19),rs3130542 and rs2853953 of human leukocyte antigen(HLA)-C,rs652888 of euchromatic histone-lysine-methyltransferase 2(EHMT2),rs2856718,rs9276370,rs7756516,and rs7453920 of HLA-DQ,rs378352 of HLA-DOA,and rs3077,rs9277535,and rs9366816 of HLA-DP.Logistic regression analyses revealed that polymorphisms such as rs9276370,rs7756516,rs7453920,rs3077,rs9277535,and rs9366816 were positively correlated with natural HBV clearance in the dominant model.Conversely,rs3130542 and rs378352 were identified as risk factors for CHB.Haplotype analysis revealed that rs9276370,rs7756516,and rs7453920 in HLA-DQ were TTG and GCA haplotypes.Although the TTG haplotype was positively correlated with a higher risk of CHB,the GCA haplotype significantly influenced the natural clearance of HBV.Bioinformatics analysis demonstrated that rs378352,rs3077,and rs9366816 were located within enhancer states;rs3077 and rs9366816 overlapped with nine tran-scription factor-binding sites,whereas rs378352 altered five sequence motifs.Furthermore,eQTL analysis demonstrated the functional tendencies of eight statistically significant SNPs(rs3130542,rs9276370,rs7756516,rs7453920,rs378352,rs3077,rs9277535,and rs9366816).Conclusions:Genetic variations within the 6p21.3 region were associated with chronic HBV infection in the Han Chinese population in southern China.Furthermore,the GCA haplotype including rs9276370,rs7756516,and rs7453920 of HLA-DQ contributed significantly to natural HBV clearance,implying that multiple SNPs exert a cumulative allelic effect on HBV infection.

NIR-enhanced Pt single atom/g-C_(3)N_(4)nanozymes as SOD/CAT mimics to rescue ATP energy crisis by regulating oxidative phosphorylation pathway for delaying osteoarthritis progression

Osteoarthritis(OA)progresses due to the excessive generation of reactive oxygen and nitrogen species(ROS/RNS)and abnormal ATP energy metabolism related to the oxidative phosphorylation pathway in the mitochondria.Highly active single-atom nanozymes(SAzymes)can help regulate the redox balance and have shown their potential in the treatment of inflammatory diseases.In this study,we innovatively utilised ligand-mediated strategies to chelate Pt^(4+)with modified g-C_(3)N_(4)byπ-πinteraction to prepare g-C_(3)N_(4)-loaded Pt single-atom(Pt SA/C_(3)N_(4))nanozymes that serve as superoxide dismutase(SOD)/catalase(CAT)mimics to scavenge ROS/RNS and regulate mitochondrial ATP production,ultimately delaying the progression of OA.Pt SA/C_(3)N_(4)exhibited a high loading of Pt single atoms(2.45 wt%),with an excellent photothermal conversion efficiency(54.71%),resulting in tunable catalytic activities under near-infrared light(NIR)irradiation.Interestingly,the Pt-N_(6) active centres in Pt SA/C_(3)N_(4)formed electron capture sites for electron holes,in which g-C_(3)N_(4)regulated the d-band centre of Pt,and the N-rich sites transferred electrons to Pt,leading to the enhanced adsorption of free radicals and thus higher SOD-and CAT-like activities compared with pure g-C_(3)N_(4)and g-C_(3)N_(4)-loaded Pt nanoparticles(Pt NPs/C_(3)N_(4)).Based on the use of H_(2)O_(2)-induced chondrocytes to simulate ROS-injured cartilage in vitro and an OA joint model in vivo,the results showed that Pt SA/C_(3)N_(4)could reduce oxidative stress-induced damage,protect mitochondrial function,inhibit inflammation progression,and rebuild the OA microenvironment,thereby delaying the progression of OA.In particular,under NIR light irradiation,Pt SA/C_(3)N_(4)could help reverse the oxidative stress-induced joint cartilage damage,bringing it closer to the state of the normal cartilage.Mechanistically,Pt SA/C_(3)N_(4)regulated the expression of mitochondrial respiratory chain complexes,mainly NDUFV2 of complex 1 and MT-ATP6 of ATP synthase,to reduce ROS/RNS and promote ATP production.This study provides novel insights into the design of artificial nanozymes for treating oxidative stress-induced inflammatory diseases.

A cyclodextrin-based nanoformulation achieves co-delivery of ginsenoside Rg3 and quercetin for chemo-immunotherapy in colorectal cancer

The immune checkpoint blockade therapy has profoundly revolutionized the field of cancer immunotherapy. However, despite great promise for a variety of cancers, the efficacy of immune checkpoint inhibitors is still low in colorectal cancer(CRC). This is mainly due to the immunosuppressive feature of the tumor microenvironment(TME). Emerging evidence reveals that certain chemotherapeutic drugs induce immunogenic cell death(ICD), demonstrating great potential for remodeling the immunosuppressive TME. In this study, the potential of ginsenoside Rg3(Rg3) as an ICD inducer against CRC cells was confirmed using in vitro and in vivo experimental approaches. The ICD efficacy of Rg3 could be significantly enhanced by quercetin(QTN) that elicited reactive oxygen species(ROS). To amelioratein vivo delivery barriers associated with chemotherapeutic drugs, a folate(FA)-targeted polyethylene glycol(PEG)-modified amphiphilic cyclodextrin nanoparticle(NP) was developed for co-encapsulation of Rg3 and QTN. The resultant nanoformulation(CD-PEG-FA.Rg3.QTN) significantly prolonged blood circulation and enhanced tumor targeting in an orthotopic CRC mouse model, resulting in the conversion of immunosuppressive TME. Furthermore, the CD-PEG-FA.Rg3.QTN achieved significantly longer survival of animals in combination with Anti-PD-L1. The study provides a promising strategy for the treatment of CRC.

Photodeposition fabrication of hierarchical layered Co-doped Ni oxyhydroxide(NixCo1−xOOH)catalysts with enhanced electrocatalytic performance for oxygen evolution reaction

Highly active,durable and inexpensive oxygen evolution reaction(OER)catalysts are crucial for achieving practical and high-efficiency water splitting.Herein,hierarchical interconnected NixCo1−xOOH nanosheet arrays supported on TiO2/Ti substrate have been fabricated through a facile photodeposition method.Compared with pristine NiOOH,the obtained NixCo1−xOOH nanosheet arrays possess larger exposed electrochemical active surface area,faster transfer and collection of electrons and stronger electronic interaction,showing a low overpotential of 350 mV at a current density of 10 mA·cm−2 and a small Tafel slope of 41 mV·dec−1 in basic solutions,with the OER performance superior to pristine NiOOH and most Ni-based catalysts.Furthermore,the NixCo1−xOOH electrode demonstrates excellent stability at the current density of 10 mA·cm−2 for 24 hours,which is attributed to the structural maintenance caused by the good adhesion of the catalyst and the substrate.Our study provides an alternative approach for the rational design of highly active and promising OER electrocatalysts.

Observation on the aerosol and ozone precursors in suburban areas of Shenzhen and analysis of potential source based on MAX-DOAS

Long-term stereoscopic observations of aerosol,NO2,and HCHO were carried out at the Yangmeikeng(YMK)site in Shenzhen.Aerosol optical depths and NO2 vertical column concentration(NO2 VCD)derived from MAX-DOAS were found to be consistent with other datasets.The total NO2 VCD values of the site remained low,varying from 2×10^(15)to 8×10^(15)mol/cm^(2),while the HCHO VCD was higher than NO2 VCD,varying from 7×10^(15)to 11×10^(15)mol/cm^(2).HCHO VCD was higher from September to early November than that was from mid-late November to December and during February 2021,in contrast,NO2 VCD did not change much during the same period.In January,NO2 VCD and HCHO VCD were both fluctuating drastically.High temperature and HCHO level in the YMK site is not only driving the ozone production up but alsomay be driving up the ozone concentration as well,and the O_(3)production regime in the YMK site tends to be NOx-limited.At various altitudes,backward trajectory clustering analysis and Potential Source Contribution Function(PSCF)were utilized to identify possible NO2 and HCHO source locations.The results suggested that the Huizhou-Shanwei border and the Daya Bay Sea area were the key potential source locations in the lower(200 m)and middle(500 m)atmosphere(WPSCF>0.6).The WPSCF valuewas high at the 1000maltitude whichwas closer to the YMKsite than the near ground,indicating that the pollution transport capability in the upper atmosphere was limited.

Epitaxial fabrication of AgTe monolayer on Ag(111)and the sequential growth of Te film

Transition-metal chalcogenides(TMCs)materials have attracted increasing interest both for fundamental research and industrial applications.Among all these materials,two-dimensional(2D)compounds with honeycomb-like structure possess exotic electronic structures.Here,we report a systematic study of TMC monolayer AgTe fabricated by direct depositing Te on the surface of Ag(111)and annealing.Few intrinsic defects are observed and studied by scanning tunneling microscopy,indicating that there are two kinds of AgTe domains and they can form gliding twin-boundary.Then,the monolayer AgTe can serve as the template for the following growth of Te film.Meanwhile,some Te atoms are observed in the form of chains on the top of the bottom Te film.Our findings in this work might provide insightful guide for the epitaxial growth of 2D materials for study of novel physical properties and for future quantum devices.

Toplayer-dependent crystallographic orientation imaging in the bilayer two-dimensional materials with transverse shear microscopy

Nanocontact properties of two-dimensional(2D)materials are closely dependent on their unique nanomechanical systems,such as the number of atomic layers and the supporting substrate.Here,we report a direct observation of toplayer-dependent crystallographic orientation imaging of 2D materials with the transverse shear microscopy(TSM).Three typical nanomechanical systems,MoS_(2) on the amorphous SiO_(2)/Si,graphene on the amorphous SiO_(2)/Si,and MoS_(2) on the crystallized Al_(2)O_(3),have been investigated in detail.This experimental observation reveals that puckering behaviour mainly occurs on the top layer of 2D materials,which is attributed to its direct contact adhesion with the AFM tip.Furthermore,the result of crystallographic orientation imaging of MoS_(2)/SiO_(2)/Si and MoS_(2)/Al_(2)O_(3) indicated that the underlying crystalline substrates almost do not contribute to the puckering effect of 2D materials.Our work directly revealed the top layer dependent puckering properties of 2D material,and demonstrate the general applications of TSM in the bilayer 2D systems.

Iterative HOEO fusion strategy:a promising tool for enhancing bearing fault feature

As parameter independent yet simple techniques,the energy operator(EO)and its variants have received considerable attention in the field of bearing fault feature detection.However,the performances of these improved EO techniques are subjected to the limited number of EOs,and they cannot reflect the non-linearity of the machinery dynamic systems and affect the noise reduction.As a result,the fault-related transients strengthened by these improved EO techniques are still subject to contamination of strong noises.To address these issues,this paper presents a novel EO fusion strategy for enhancing the bearing fault feature nonlinearly and effectively.Specifically,the proposed strategy is conducted through the following three steps.First,a multi-dimensional information matrix(MDIM)is constructed by performing the higher order energy operator(HOEO)on the analysis signal iteratively.MDIM is regarded as the fusion source of the proposed strategy with the properties of improving the signal-to-interference ratio and suppressing the noise in the low-frequency region.Second,an enhanced manifold learning algorithm is performed on the normalized MDIM to extract the intrinsic manifolds correlated with the fault-related impulses.Third,the intrinsic manifolds are weighted to recover the fault-related transients.Simulation studies and experimental verifications confirm that the proposed strategy is more effective for enhancing the bearing fault feature than the existing methods,including HOEOs,the weighting HOEO fusion,the fast Kurtogram,and the empirical mode decomposition.

Biomimetic gold nanocomplexes for gene knockdown： Will gold deliver dividends for small interfering RNA nanomedicines？

RNA interference （RNAi） effectors such as small interfering RNA （siRNA） and micro RNA （miRNA） can selectively downregulate any gene implicated in the pathology of a disease. Therefore, RNAi-based therapies have immense potential for the treatment of a wide range of diseases. However, pharmacokinetic and pharmacodynamic studies have revealed that these therapeutic agents have poor bioactivity due to a number of factors, including insufficient plasma drug levels, short plasma half-lives, renal clearance, and hepatic metabolism. Non-viral delivery may facilitate the clinical application of siRNA-based therapeutics by helping to overcome these barriers. Recently, the potential of gold nanoparticles （AuNPs） as multifunctional carriers for transporting drugs, proteins, and genetic materials has been demonstrated. In this review, some of the key properties of AuNPs relevant to siRNA delivery, such as physical properties and surface chemistry have been described. In addition, the ability of AuNP-based formulation strategies to successfully overcome delivery barriers associated with siRNA, and the potential for this material to translate into safe and effective nanomedicines are critically discussed.

Advanced atomic force microscopies and their applications in two-dimensional materials:a review

Scanning probe microscopy(SPM)allows the spatial imaging,measurement,and manipulation of nano and atomic scale surfaces in real space.In the last two decades,numerous advanced and functional SPM methods,particularly atomic force microscopy(AFM),have been developed and applied in various research fields,from mapping sample morphology to measuring physical properties.Herein,we review the recent progress in functional AFM methods and their applications in studies of two-dimensional(2D)materials,particularly their interfacial physical properties on the substrates.This review can inspire more exciting application works using advanced AFM modes in the 2D and functional materials fields.