Objective:To investigate the factors influencing fall risk scores in elderly individuals.Methods:A total of 4 419 individuals were randomly selected using the cluster sampling method from Beijing, Nanning(Guangxi), and Yinchuan(Ningxia).Data on demographic characteristics and fall-related incidents were gathered and analyzed for their correlation with fall risk scores.Results:The fall risk score showed significant associations with various factors, such as the history of falls within one year( β=-3.607, 95% CI: -3.881 to -3.332), care methods( β=2.442, 95% CI: 2.226 to 2.658), exercise( β=0.714, 95% CI: 0.443 to 0.986), retirement( β=-0.585, 95% CI: -0.819 to -0.351), age( β=0.173, 95% CI: 0.159 to 0.187), and use of walking aids( β=-3.737, 95% CI: -4.054 to -3.421). Conclusions:Fall risk scores in older adults are influenced by a variety of factors.Factors such as no history of falls within the past year, living independently, engaging in physical activity, and being employed may contribute to lower fall risk scores in older adults.

AIM To establish the HPLC fingerprints for Tanacetum tatsienense(Bureau & Franchet)K.Bremer & Humphries and to determine the contents of chlorogenic acid,quercetin-3-O-glucoside,luteolin-7-O-glucoside,luteolin-7-O-glucuronide,apigenin-7-O-glucuronide,luteolin and apigenin.METHODS The analysis was performed on a 35 ℃ thermostatic Agilent ZORBAX Extend C18 column(4.6 mm×250 mm,0.5 μm),with the mobile phase comprising of 0.5％phosphoric acid-acetonitrile flowing at 1.0 mL/min,and the detection wavelength was set at 350 nm.Subsequently,principal component analysis,partial least squares discriminant analysis and cluster analysis were carried out.RESULTS There were twelve common peaks in the fingerprints for fourteen batches of samples with the similarities of 0.761-0.975.Seven constituents showed good linear relationships within their own ranges(R2≥0.999 1),whose average recoveries were 84.00％-105.11％with the RSDs of 1.28％-2.86％.Various batches of samples were clustered into three types,and seven differential constituents were observable,containing peaks 4(luteolin-7-O-glucoside),12(apigenin),9(apigenin-7-O-glucuronide),8,11(luteolin),5(luteolin-7-O-glucuronide)and 2.CONCLUSION This precise,stable,specific and reproducible method can be used for the quality control of T.tatsienense.

Objective To propose a Q factor-based fatigue vibration evaluation method of the ultrasonic knife tip.Methods Firstly,an ultrasonic cutter fatigue testing table was established to realize repeated cutting,which was composed of a power supply module,a three-axis moving module,an ultrasonic cutter clamping module and a control module.Secondly,10 ultrasonic knives of some brand underwent fatigue testing with the table,during which non-contact measurement of the ultrasonic knife tip vibration was carried out and the Q factors were calculated at the five periods of the fatigue test,including the periods before cutting,after 500 times of cutting,after 1 000 times of cutting,after 2 000 times of cutting and after 3 000 times of cutting.Finally,the average cutting speed and burst pressure for coagulated vessels were computed at each period to validata the effectiveness of the method proposed.Results It's indicated that Q factor could effectively reflect the fatigue degradation of the ultrasonic knife tip,while the average cutting speed and burst pressure for coagulated vessels were difficult to efficiently evaluate the fatigue degradation level of the ultrasonic knife tip due to the uncertainty factors in the measurement process.Conclusion The proposed Q factor-based evaluation method can directly evaluate fatigue vibration of the ultrasonic knife tip in an accurate and quantitative manner.[Chinese Medical Equipment Journal,2024,45(6):17-22]

Objective To carry out accurate quantative evaluation of MRI scanning noise based on laser vibrometry technology.Methods Skull and spine MRI was performed with mute and conventional sequences.A laser vibrometry device was used to sample the surface vibration noise at the outer edge of the inspection hole of MRI system according to GB/T 16539-1996 Acoustics—Determination of sound power levels of noise sources using vibration velocity—Measurement for seal machinery,and the indicators of sound power level,sound pressure level and perceived noise level obtained by the three calculation methods(LPN1,LPN2 and LPN3)were analyzed with some dedicated MRI noise analysis software.Results The peak sound pressure levels for conventional and mute sequences of skull scanning were 81 and 63 dB(A),respectively,and mute sequence reduced the noise level significantly;the peak sound pressure levels for conventional and mute sequences of spine scanning were 79 and 75 dB(A),respectively,and the noise reduction level was significantly lower than that of skull scanning.Significant differences in noise reduction were not found in spine scanning sequences,while were found in skull scanning sequences.During spine and skull scanning LPN1,LPN2 and LPN3 obtained by the three calculation methods of conventional and mute sequences were all higher than the overall sound power and overall pressure levels obviously.Conclusion Mute sequence can not realize linear noise reduction for the whole frequency band,the perceived noise of the human ear during MRI scanning is related directly to the scanning sequence,and there may be some bias when only one physical indicator is involved in the noise evaluation of MRI system.[Chinese Medical Equipment Journal,2024,45(10):20-24]

BACKGROUND:Animal models of diabetic encephalopathy that have been studied mainly include streptozotocin-induced model,high-sugar and high-fat diet-induced model and spontaneous animal model.Establishing a simple,easy,short-cycle,safe and effective model of diabetic encephalopathy can help to explore the subsequent pathogenesis and screen therapeutic drugs. OBJECTIVE:To further explore and evaluate the method of building diabetic encephalopathy rat models. METHODS:Twenty Sprague-Dawley rats were randomly divided into control(n=10)and model(n=10)groups.Rats in the model group were given a single injection of 45 mg/kg streptozotocin in the left lower abdominal cavity,and those in the control group were given the same amount of citrate buffer.During the experiment,the body mass,feed intake,water intake and blood glucose were measured.After 8 weeks,the glucose tolerance and oxidative stress levels were measured,and the pathological changes of brain tissue and the expression of apoptotic proteins were compared between groups. RESULTS AND CONCLUSION:Compared with the control group,the food intake,water intake,encephalization quotient,blood glucose and area under the blood glucose curve were significantly increased in the model group,while the body mass decreased significantly(P<0.01).Histopathological examination of the brain showed that compared with the control group,the number of surviving nerve cells was significantly reduced in the model group(P<0.01),with more significant pathological damage of nerve cells.Compared with the control group,the activities of serum superoxide dismutase,catalase and glutathione in the model group were significantly decreased(P<0.01),and the content of oxidative malondialdehyde was significantly increased(P<0.05).The expression levels of apoptosis-related proteins Bax and Caspase-3 in brain tissue increased in the model group compared with the control group,while the expression of Bcl-2 decreased(P<0.01).In conclusion,an 8-week injection of 45 mg/kg streptozotocin can cause obvious pathological damage to the brain tissue of diabetic rats,to successfully establish the rat model of diabetic encephalopathy.

Objective To develop a physiological pharmacokinetic(PBPK)model of ritonavir,simulate ritonavir-mediated drug interactions,and provide future predictions for ritonavir pharmacokinetics(PK)and drug-drug interaction(DDI).Methods The PBPK model of ritonavir was constructed by searching relevant databases,collecting data on the physicochemical properties,PK,DDI related parameters and clinical studies of ritonavir,and using PK-Sim software to optimize and validate the parameters of the model to evaluate the performance of the constructed PBPK model in describing the PK characteristics and predicting the DDI of ritonavir.Results The ritonavir PBPK model demonstrated good performance,and by calculating the geometric mean folded error(GMFE)between the Sim and actual Obs values,the GMFEs of ritonavir AUC and Cmax were 1.11 and 1.16,respectively,and the GMFEs of ritonavir AUC and Cmax after combination with ritonavir were 1.24 and 1.26,respectively.Conclusion The PBPK model of ritonavir has been successfully constructed,and the effect of ritonavir on the metabolic enzyme cytochrome P450 3A4 is significant.Therefore,when ritonavir is combined with the victim drugs,individualized dosing can be guided according to the PBPK model.

The interaction between Mycobacterium tuberculosis and host, as well as the regulation of some signaling pathways in the host, were involved in pathogen latency in macrophages. microRNAs (miRNAs) regulate the gene expression and biological functions, indicating that miRNAs played a regulatory role in bacterial infections. However, whether the host's miRNAs were also involved in the process of Mycobacterium tuberculosis infection had not been thoroughly studied. This study infected macrophages with pathogenic Mycobacterium tuberculosis strain H37Rv and low virulence strain H37Ra to explore the functional miRNAs. By identifying the expression profile of miRNAs in host cells after infection, the expression of 17 miRNAs significantly changed (P < 0.05) in the human macrophage THP-1 infected with highly pathogenic H37Rv strain (Rv), H37Rv inactivated strain (Rv-), and non-pathogenic H37Ra (Ra) strains respectively, indicating that host miRNAs may be involved in the interaction of Mycobacterium tuberculosis and host. Meanwhile, 10 types of miRNAs showed significant differences in cells infected with pathogenic and non-pathogenic Mycobacterium tuberculosis, suggesting that host miRNAs may play an important role in the pathogenicity and intracellular survival of Mycobacterium tuberculosis. Further study had found that miR-449a, miR-502-5p, and miR-708 were downregulated in cells infected with Mycobacterium marinum. Overexpression of these three miRNAs displayed the significant inhibitory effect on the growth of Mycobacterium marinum, indicating that miRNAs played a pivotal role in the interaction between the host and Mycobacterium marinum. This study provided the new insights into the pathogenesis of Mycobacterium tuberculosis and the treatment of tuberculosis.

The synergistic antibacterial strategy of peroxidase mediated chemodynamic therapy(CDT)and photothermal therapy(PTT)has been proven to effectively resist bacteria.However,the antibacterial effect against Pseudomonas aeruginosa is severely limited due to the factors such as short lifespan of reactive oxygen species(ROS)(<200 ns)and limited diffusion distance(about 20?200 nm).In this study,glucopyranose functionalized MoO3-x(P-MoO3-x)nanoenzyme was successfully synthesized using a one-pot hydrothermal method.This nanoenzyme exhibited both peroxidase-like activity and a photothermal effect.The combined antibacterial performance and biological safety of P-MoO3-x was analyzed and verified.By utilizing specific interactions with glucopyranose and lectin,P-MoO3-x nanoenzyme could target the surface of Pseudomonas aeruginosa.This targeted approach effectively shortened the range of hydroxyl radicals,significantly enhancing the antibacterial effect against Pseudomonas aeruginosa.Under photothermal action,P-MoO3-x could reach the optimal reaction effect at 70℃.Even at low concentrations of hydrogen peroxide(50 μmol/L),it released more hydroxyl radicals.In vitro antibacterial analysis experiments demonstrated that the inactivation efficiency of the P-MoO3-x antibacterial system against Pseudomonas aeruginosa(106 CFU/mL)exceeded 99%.Furthermore,in vivo experiments confirmed the significant therapeutic effects of P-MoO3-x in treating methicillin-resistant Staphylococcus aureus(MRSA)infected wounds and promoting wound healing,without producing toxicity to cells.In conclusion,P-MoO3-x exhibited excellent antibacterial ability and good biocompatibility,making it a promising anti-infective nanoenzyme with broad application prospects.

Objective To investigate the effect of microplastic(MPs)exposure on learning and memory in mice,and its mechanism by observing the protein expression of brain-derived neurotrophic factor(BDNF)/tyrosine receptor kinase B(TrkB)/N-methyl-D-aspartate receptor subtype 2B(NR2B)signaling pathway and neurogenesis.Methods Forty male C57BL/6 mice were randomly divided into control group(Ctrl)and microplastics exposure group(MPs).Mice in MPs group were treated with 0.3 mg/(kg·d)microplastics,administered by gavage at a volume of 200 μl for 30 consecutive days.Morris water maze test was used to evaluate the spatial learning and memory ability of mice.Western blotting was used to detect the protein levels of BDNF,TrkB and NR2B in hippocampus of mice.Immunofluorescent staining was used to observe the number of doublecortin(DCX)and neuronal nuclei antigen(NeuN)positive cells in the hippocampus of mice to evaluate hippocampal neurogenesis.Results Compared with the control group,the ability of learning and memory decreased significantly in MPs group mice(P＜0.01).The expression levels of BDNF,TrkB and NR2B in the hippocampus of MPs group mice were significantly lower than those of control group(P＜0.05).The number of DCX and NeuN positive cells in the hippocampus of MPs group was significantly lower than that of control group(P＜0.01).Conclusion MPs exposure induces learning and memory impairment which may be related to inhibiting BDNF/TrkB/NR2B signaling pathway and reducing hippocampal neurogenesis.

Abstract：Objective To prepare human monoclonal antibody against spike protein（S protein）of severe acute respiratory syndrome coronavirus 2（SARS⁃CoV⁃2）by using single B cell，and determine its neutralizing activity. Methods Venous blood with high antibody level was collected from people immunized with inactivated SARS⁃CoV⁃2 vaccine（Vero cells） twice，of which peripheral blood mononuclear cells（PBMCs）were isolated by lymphocyte stratified fluid and used to isolate single B cell expressing S protein antibody by magnetic beads coupled with S1 protein. Variable region genes of IgG heavy chain and light chain were amplified by nested PCR after reverse transcription of single B cell，which were connected with CMV promoter，IgG leader sequence，IgG constant region and polyA sequence by overlapping PCR to construct antibody linear expression cassette. Linear expression cassette of the heavy chain and light chain from the same B cell was transfected to HEK293T cells to express human monoclonal antibody of SARS⁃CoV⁃2 S protein. Immunoreactivity was detected by immuno⁃ fluorescence while neutralizing activity by pseudovirus neutralization test. Results A total of 26 monoclonal antibodies against SARS⁃CoV⁃2 S protein were expressed，which showed heavy chain and light chain protein bands of IgG antibody at