Time-of-flight secondary ion mass spectrometer(TOF-SIMS)is a highly sensitive surface analysis instrument with high spatial resolution.Traditional TOF-SIMS instruments for sample targets use high field extraction methods.Although the ion collection efficiency is high,it is prone to issues such as low-energy ion beam defocusing,sample morphology sensitivity,and organic molecule ion dissociation.This study aimed to develope an efficient low-field ion extraction system suitable for TOF-SIMS with a continuous beam source.The SIMION simulation software was used to construct a model of the secondary ion optical extraction system.The key factors affecting the extraction efficiency were studied,and the structural parameters of the extraction cone were optimized.Using an indium target as the sample,an experimental test of the performance of the ion extraction system was carried out on the TOF-SIMS instrument.The influences of the voltages of the ion extraction cone and the single lens on the ion extraction efficiency were consistent with the simulation results.By adopting the technology of deflection and coaxial dynamic compensation,the imaging field of view of the ion extraction system was increased to 500 μm×500 μm.The energy window of the ion extraction system reached 10 eV,and the large imaging depth of field of 400 μm was achieved.In the test of a 5 mg/L cholesterol thin film sample,the signal-to-noise ratio of the characteristic peak[M-OH]+reached 4453.The results showed that this low-field secondary ion extraction system effectively improved the performance of the continuous beam TOF-SIMS instrument.

Biochemistry,as a fundamental course for science and engineering majors related to biology and chemistry,holds a significant position in the curriculum.The course team at Dalian Minzu University is committed to teaching innovation,adopting the outcome-based education(OBE)concept for teaching de-sign and incorporating ideological and political elements,in order to achieve the dual goals of knowledge transmission and value guidance.The team has established a three-dimensional teaching goal of"knowl-edge,morality,and ability",covering"consolidating core knowledge,cultivating moral sentiment,and enhancing innovation ability".Through a multi-dimensional integrated teaching method of"three integra-tions and five combinations",multiple rounds of teaching practice have been carried out in the applied chemistry major using"classification and specificity of enzyme"as an example.The output of teaching re-sults and survey questionnaires show that students highly recognize the teaching design and its"process-based learning"evaluation method,fully reflecting the student-centered teaching idea.Research has shown that OBE design combined with ideological and political elements can effectively promote students' knowl-edge acquisition,moral growth,and innovation ability improvement in the course of Biochemistry.This teaching design not only helps students construct correct worldviews,outlooks on life,and values,but also significantly enhances their innovative thinking and practical abilities.This teaching design can not only ef-fectively improve the teaching quality of the course,but also provide new perspectives and ideas for the teaching design of Biochemistry,realizing the organic integration of professional knowledge imparting and i-deological and political education,and has certain innovation and practical significance.

Biochemistry,as a fundamental course for science and engineering majors related to biology and chemistry,holds a significant position in the curriculum.The course team at Dalian Minzu University is committed to teaching innovation,adopting the outcome-based education(OBE)concept for teaching de-sign and incorporating ideological and political elements,in order to achieve the dual goals of knowledge transmission and value guidance.The team has established a three-dimensional teaching goal of"knowl-edge,morality,and ability",covering"consolidating core knowledge,cultivating moral sentiment,and enhancing innovation ability".Through a multi-dimensional integrated teaching method of"three integra-tions and five combinations",multiple rounds of teaching practice have been carried out in the applied chemistry major using"classification and specificity of enzyme"as an example.The output of teaching re-sults and survey questionnaires show that students highly recognize the teaching design and its"process-based learning"evaluation method,fully reflecting the student-centered teaching idea.Research has shown that OBE design combined with ideological and political elements can effectively promote students' knowl-edge acquisition,moral growth,and innovation ability improvement in the course of Biochemistry.This teaching design not only helps students construct correct worldviews,outlooks on life,and values,but also significantly enhances their innovative thinking and practical abilities.This teaching design can not only ef-fectively improve the teaching quality of the course,but also provide new perspectives and ideas for the teaching design of Biochemistry,realizing the organic integration of professional knowledge imparting and i-deological and political education,and has certain innovation and practical significance.

Aim To explore the mechanism of Epimedii folium-Astmgali radix activating the SCF/c-kit signa-ling pathway to activate the PI3K/Akt signaling path-way and its effect on sperm production and vitality in oligoasthenospermia.Methods Sixty male SD rats were used to establish a model of oligoasthenospermia with cyclophosphamide.They were randomly divided into six groups:experimental group(further divided into high,medium,and low dose group),model group,control group and blank group.The oligoasthenosper-mia model was established by using cyclophosphamide in experimental group,levocarnitine group and model group.The rats in the high,medium,and low dose group of the experimental group were orally adminis-tered Epimedii folium-Astmgali radix extract at doses of 800,400,and 200 mg·kg-1,respectively,Once daily for 35 days.Rats of the control group were orally ad-ministered 250 mg·kg-1·d-1 of levocarnitine,Once daily for 35 days.ELISA was used to detect serum of T,E2,FSH,and LH.Western blot and IHC staining were used to detect the expression of SCF,c-kit,Bcl-2,Bax,PI3K,and Akt proteins in rat testicular tissues.Sperm activity is examined by microscopy.The testicu-lar tissue structure and cell morphology of rats in each group were observed.Results Compared with the model group,Epimedii folium-Astmgali radix increased the sperm density,total viability rate,and vitality(P＜0.05,P＜0.01),decreased sperm apoptosis rate and LH,T,and E2 levels(P＜0.05,P＜0.01),decreased Bax protein expression in testicular tissue(P＜0.01),and increased Bcl-2,SCF,c-Kit,PI3K,and Akt protein expression(P＜0.05,P＜0.01);it increased the number of germ cells,thickened basement membrane,and significantly improved seminiferous tubule mor-phology,even showing germ cells at different develop-mental stages and mature sperm.Conclusions Epi-medii folium-Astmgali radix has a significant therapeu-tic effect on oligoasthenospermia in rats.Its mechanism may be related to the activation of the SCF/c-kit signa-ling pathway to activate the PI3K/Akt signaling path-way promoting the proliferation and differentiation of germ cells,and promoting sperm production,maturation and motility.

Objective The aim of the study is to reveal the polymorphisms of Eustrongylides spp.in Monopterus albus.Methods A total of five Eustrongylides spp.collected from five M.albus in the Yongzhou area were sampled to amplify ribosomal ITS sequence by PCR in vitro,then sequenced after extracting the DNA templates of Eustrongylides.The phylogenetic tree based on the ITS sequence was also constructed to explore the evolutionary history of Eustrongylides.Results The length of the ITS sequence of the five Eustrongylides spp.is approximately 933 bp,and the genetic differences between the isolates are 0.00％-0.90％and the genetic inheritance differences with other nematodes are 15.5％-18.20％,maintaining a certain genetic distance from other families.Conclusions The ITS sequence of Eustrongylides spp.in M.albus will be used as a genetic marker for the molecular identification of Eustrongylides spp.and will provide a basis for the prevention and control of Eustrongylides spp.in the future.

Aim To explore the mechanism of Epimedii folium-Astmgali radix activating the SCF/c-kit signa-ling pathway to activate the PI3K/Akt signaling path-way and its effect on sperm production and vitality in oligoasthenospermia.Methods Sixty male SD rats were used to establish a model of oligoasthenospermia with cyclophosphamide.They were randomly divided into six groups:experimental group(further divided into high,medium,and low dose group),model group,control group and blank group.The oligoasthenosper-mia model was established by using cyclophosphamide in experimental group,levocarnitine group and model group.The rats in the high,medium,and low dose group of the experimental group were orally adminis-tered Epimedii folium-Astmgali radix extract at doses of 800,400,and 200 mg·kg-1,respectively,Once daily for 35 days.Rats of the control group were orally ad-ministered 250 mg·kg-1·d-1 of levocarnitine,Once daily for 35 days.ELISA was used to detect serum of T,E2,FSH,and LH.Western blot and IHC staining were used to detect the expression of SCF,c-kit,Bcl-2,Bax,PI3K,and Akt proteins in rat testicular tissues.Sperm activity is examined by microscopy.The testicu-lar tissue structure and cell morphology of rats in each group were observed.Results Compared with the model group,Epimedii folium-Astmgali radix increased the sperm density,total viability rate,and vitality(P＜0.05,P＜0.01),decreased sperm apoptosis rate and LH,T,and E2 levels(P＜0.05,P＜0.01),decreased Bax protein expression in testicular tissue(P＜0.01),and increased Bcl-2,SCF,c-Kit,PI3K,and Akt protein expression(P＜0.05,P＜0.01);it increased the number of germ cells,thickened basement membrane,and significantly improved seminiferous tubule mor-phology,even showing germ cells at different develop-mental stages and mature sperm.Conclusions Epi-medii folium-Astmgali radix has a significant therapeu-tic effect on oligoasthenospermia in rats.Its mechanism may be related to the activation of the SCF/c-kit signa-ling pathway to activate the PI3K/Akt signaling path-way promoting the proliferation and differentiation of germ cells,and promoting sperm production,maturation and motility.

Aim To investigate the protective effect of carnosine on BV2 cell damage induced by oxygen-glu-cose deprivation/reperfusion(OGD/R)and its role in mediating pyrodeath through the ROS/NLRP3/GSDMD pathway.Methods BV2 cells were randomly divided into the control group(Con),model group(OGD/R),carnosine group(OGD/R+CAR),inhibitor group(OGD/R+MCC950),and carnosine+inhibitor group(OGD/R+CAR+MCC950).The cell survival rate was detected by MTT assay.The release rate of lactate dehydrogenase(LDH)in cell supernatant was detected by microenzyme labeling method.Cell damage was as-sessed using Hoechst 33342/SYTOX Green staining.ROS levels in cells were detected by DCFH-DA.The nucleation level of NF-κB p65 was observed by immu-nofluorescence.The protein expression levels of NLRP3,ASC,cleaved caspase-1,and GSDMD-N were detected by Western blot.The levels of IL-1 β and IL-18 in the supernatant were detected by ELISA.Results Com-pared with Con group,the survival rate of cells in the OGD/R group was significantly reduced,LDH release was significantly raised,cell morphology was damaged,and the positive rate of SYTOX Green was significantly elevated with ROS level in cells.The fluorescence in-tensity of NF-κB p65 in the nucleus increased,and the protein expression levels of NLRP3,ASC,cleaved caspase-1,GSDMD-N increased significantly,and the levels of IL-1 β and IL-18 in the cell superserum in-creased significantly.Compared with the OGD/R group,the survival rate of cells in other groups in-creased significantly,the LDH release rate significantly decreased,and the cell damage was improved to a cer-tain extent.The positive rate of SYTOX Green and ROS production in cells significantly decreased,and the fluorescence intensity of NF-κB p65 in nucleus markedly decreased.The expression levels of related proteins and the levels of IL-1 β and IL-18 in cell super-natant significantly decreased.Conclusion Carnosine can protect BV2 cells from OGD/R-induced damage by inhibiting oxidative stress and NF-κB activation,then inhibiting NLRP3/GSDMD signaling pathway.

Hepatic fibrosis(HF)is a pathophysiological outcome of chronic liver injury and is characterized by excessive accumulation of extracellular matrix protein.A number of studies have confirmed that the signaling pathways formed by transforming growth factor-β1(TGF-β1)and its downstream Smad family play an important role in the occurrence and development of HF,and the traditional Chinese medicine(TCM)research targeting this pathway is currently a hot spot in the reversal of HF.Therefore,taking TGF-β1/Smads signaling pathway as the entry point,this paper reviewed the mechanism of action of TCM compound formula and single drug extract in intervening TGF-β1/Smad pathway and related factors upstream and downstream of the pathway to reverse HF in recent years,revealed the targeted therapeutic effect of TCM,and provided new strategies for clarifying the mechanism of TCM.

AIM To establish a UPLC-MS/MS method for the simultaneous content determination of chlorogenic acid,mulberroside A,dihydromorin,oxyresveratrol,quercetin,kaempferol,mulberrofuran G,kuwanon G,sanggenon C,sanggenone D and morusin in Mori Cortex.METHODS The analysis was performed on a 35 ℃ thermostatic Brownlee SPP C18 column ( 2.1 mm × 100 mm,2.7 μm ),with the mobile phase comprising of acetonitrile ( containing 0.1％ formic acid)-5 mmol/L ammonium acetate flowing at 0.5 mL/min in a gradient elution manner,and electron spray ionization source was adopted in negative ion scanning with multiple reaction monitoring mode.RESULTS Eleven constituents showed good linear relationships within their own ranges (R2>0.9950),whose average recoveries were 94.53％-103.58％ with the RSDs of 2.51％-6.92％.Kaempferol was not detected in 18 batches of medicinal materials,oxyresveratrol,quercetin,mulberrofuran G,kuwanon G and morusin mainly existed in the outer crude bark,and mulberroside A content demonstrated obvious difference in different producing areas of medicinal materials.CONCLUSION This stable,rapid and sensitive method can be used for the quality control of Mori Cortex.

Objective To understand the change in distribution and antimicrobial resistance of bacteria isolated from blood specimens of Hunan Province,and provide for the initial diagnosis and treatment of clinical bloodstream infection(BSI).Methods Data reported from member units of Hunan Province Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacterial antimicrobial resistance surveillance method was imple-mented according to the technical scheme of China Antimicrobial Resistance Surveillance System(CARSS).Bacteria from blood specimens and bacterial antimicrobial susceptibility testing results were analyzed by WHONET 5.6 soft-ware and SPSS 27.0 software.Results A total of 207 054 bacterial strains were isolated from blood specimens from member units in Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021,including 107 135(51.7％)Gram-positive bacteria and 99 919(48.3％)Gram-negative bacteria.There was no change in the top 6 pathogenic bacteria from 2012 to 2021,with Escherichia coli(n=51 537,24.9％)ranking first,followed by Staphylococcus epidermidis(n=29 115,14.1％),Staphylococcus aureus(n=17 402,8.4％),Klebsiella pneu-moniae(17 325,8.4％),Pseudomonas aeruginosa(n=4 010,1.9％)and Acinetobacter baumannii(n=3 598,1.7％).The detection rate of methicillin-resistant Staphylococcus aureus(MRSA)decreased from 30.3％in 2015 to 20.7％in 2021,while the detection rate of methicillin-resistant coagulase-negative Staphylococcus(MRCNS)showed an upward trend year by year(57.9％-66.8％).No Staphylococcus was found to be resistant to vancomy-cin,linezolid,and teicoplanin.Among Gram-negative bacteria,constituent ratios of Escherichia coli and Klebsiella pneumoniae were 43.9％-53.9％and 14.2％-19.5％,respectively,both showing an upward trend(both P＜0.001).Constituent ratios of Pseudomonas aeruginosa and Acinetobacter baumannii were 3.6％-5.1％and 3.0％-4.5％,respectively,both showing a downward trend year by year(both P＜0.001).From 2012 to 2021,resistance rates of Escherichia coli to imipenem and ertapenem were 1.0％-2.0％and 0.6％-1.1％,respectively;presenting a downward trend(P＜0.001).The resistant rates of Klebsiella pneumoniae to meropenem and ertapenem were 7.4％-13.7％and 4.8％-6.4％,respectively,presenting a downward trend(both P＜0.001).The resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannii to carbapenem antibiotics were 7.1％-15.6％and 34.7％-45.7％,respectively.The trend of resistance to carbapenem antibiotics was relatively stable,but has de-creased compared with 2012-2016.The resistance rates of Escherichia coli to the third-generation cephalosporins from 2012 to 2021 were 41.0％-65.4％,showing a downward trend year by year.Conclusion The constituent ra-tio of Gram-negative bacillus from blood specimens in Hunan Province has been increasing year by year,while the detection rate of carbapenem-resistant Gram-negative bacillus remained relatively stable in the past 5 years,and the detection rate of coagulase-negative Staphylococcus has shown a downward trend.