Supercooling preservation technology, as a groundbreaking innovation in the field of organ preservation, significantly reduces the metabolic rate of cells and inhibits ice crystal formation by placing organs in a low-temperature environment near or below the freezing point. This technology extends the preservation time of organs and maintains their biological activity. Compared with the traditional low-temperature preservation at 4 °C, supercooling preservation effectively avoids cell damage and the accumulation of metabolic products, demonstrating significant advantages in the preservation of cells, tissues and organs. In recent years, important progress has been made in the optimization of cryoprotectants, the application of antifreeze proteins, the improvement of vitrification technology, and the development of nanotechnology-based rewarming techniques. These advancements provide new pathways to address the challenges of toxicity, ice crystal formation and uneven rewarming rates during supercooling preservation. This review summarizes the basic principles of supercooling preservation, the application of key technologies, and their practical effects in organ transplantation. It also analyzes the challenges of toxicity and rewarming efficiency, aiming to provide theoretical support and research directions for the future optimization of organ low-temperature preservation technology and its clinical application.

Objective To investigate the compressive relaxation behavior of cartilage in different regions of the knee joint at different strain rates,and construct the viscoelastic mechanics of cartilage in each region,so as to provide a reference for the prevention of cartilage-related diseases and the development of cartilage repair materials.Methods The knee cartilage of beagle dogs was regionally divided,and the uniaxial unconfined compressive relaxation properties of cartilage in each region were tested by a universal testing machine at different strain rates,and the constitutive models were constructed.Results The cartilage exhibited a notable stress attenuation.Furthermore,the normalized stress reduction increased significantly with increasing strain rate.For cartilage in lateral plateaus of tibia,the normalized stress reduction at strain rate 5×10-4 s-1 was 19%,and increased to 69%at strain rate 5×10-2 s-1.The relaxation equilibrium stress remained relatively constant at all strain rates.The Ogden-Prony viscoelastic model of cartilage in each region was developed with a goodness of fit R2>0.98.Conclusions The knee cartilage demonstrates a significant viscoelastic response in relaxation tests,exhibiting the rate-dependent and region-dependent properties.The Ogden-Pony viscoelastic model can reflect the strain rate-dependent stress relaxation behavior of cartilage.

Objective:To understand the factors influencing new infections of 9-valent vaccine-type human papillomavirus (9-valent type HPV) among men who have sex with men (MSM) in Urumqi City and to construct a prediction model of individual dynamics of new infections of 9-valent type HPV among MSM.Methods:In this study, a snowball method was adopted to recruit MSM in Urumqi City to establish a dynamic cohort, and participants were followed up every 6 months from 2016 to 2023, and perianal exfoliated cells were collected for HPV genotyping; joint models were established using the number of same-sex sexual partners in the last six months and the number of anal intercourse in the last one week as longitudinal variables, respectively, and joint models were utilized to analyze the influence factors of 9-valent HPV new infections in MSM individuals were analyzed by the joint model; the predictive efficacy of the model in the follow-up period was evaluated by using the time-dependent receiver operating characteristic area under the curve (AUC) values. Based on the prediction model, two study participants were randomly selected for individual dynamic prediction of new-onset HPV infections of 9-valent type types.Results:MSM with at least two follow-up visits 579 individuals were included in the analysis. The results of the two joint models showed that being divorced/widowed [hazard ratio ( HR)=1.544, 95% CI: 1.033-2.233], having a sexual behavior style of being the inserted party ( HR=1.366, 95% CI: 1.053-1.764), and having a history of STDs ( HR=1.659, 95% CI: 1.057-2.558) increased the 9-valent types of new HPV infections risk. The results of the shared parameter of the joint model of the number of same-sex partners in the last six months showed that each 2.72 increase in the number of same-sex partners in the last six months was associated with a 28.2% increase in the risk of new 9-valent HPV infections in MSM individuals ( HR=1.282, 95% CI: 1.065-1.540). The time-dependent AUC results showed that the joint model for the number of same-sex sexual partners in the last six months (0.808 0) predicted better performance than the joint model for the number of anal intercourse in the last one week (0.750 0). The joint model based on the number of same-sex sexual partners in the last six months for the prediction of MSM individual dynamics was consistent with the real situation. Conclusion:The joint model based on the number of same-sex sexual partners in the last six months, sexual behavior, history of STDs, and other risk factors has high accuracy in predicting the risk of new MSM 9-valent HPV infections in Urumqi City, which can provide a scientific basis for the prediction of individual dynamics of new MSM 9-valent HPV infections.

This study investigated the disease characteristics and clinical traits of Nocardia infection,and analyzed the antibiotic resistance phenotypes,antibiotic resistance genes,and evolutionary characteristics of the strains,to provide a basis for Nocardia diag-nosis and treatment.A total of 31 Nocardia strains from a hospital in Hebei Province were collected from 2020 to 2023.The strains were identified through mass spectrometry and whole genome sequencing.Antibiotic susceptibility testing was conducted with the broth macrodilution method,and whole genome sequencing data were used to predict antibiotic resistance genes and comprehensively ana-lyze antibiotic resistance phenotypes.The 31 strains of Nocardia comprised 21 strains of Nocardia farcinica,3 strains of Nocardia ter-penica,three strains of Nocardia brasiliensis,two strains of Nocardia cyriacigeorgica,and two strains of Nocardia nova.The ceftriaxone susceptibility of 21 Nocardia farcinica strains was 85.7%,and all 31 strains were susceptible to imipenem,except for three strains of Nocardia brasiliensis.Rifampicin,aminoglycoside,and β-lactam resistance genes were found in Nocardia farcinica.Pathogenic tests should be carried out in a timely manner for suspected Nocardia infections.In clinical treatment of Nocardia infection,infected strains should be confirmed,and antibiotics should be used rationally according to the antibiotic susceptibility test results.

OBJECTIVE: To prepare clinical-grade human umbilical cord-derived mesenchymal stem cells (hUC-MSC) with high expression of hematopoietic supporting factors and evaluate their stem cell characteristics. METHODS: Fetal umbilical cord tissues were collected from healthy postpartum women during full-term cesarean section. Wharton's jelly was mechanically separated and hUC-MSCs were obtained by explant culture method and enzyme digestion method in an animal serum-free culture system with addition of human platelet lysate. The phenotypic characteristics of hUC-MSCs obtained by two methods were detected by flow cytometry. The differences in proliferation ability between the two groups of hUC-MSCs were identified through CCK-8 assay and colony forming unit-fibroblast (CFU-F) assay. The differences in multilineage differentiation potential between the two groups of hUC-MSCs were identified through induction of adipogenic, osteogenic, and chondrogenic differentiation. The mRNA expression levels of hematopoietic supporting factors such as SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in the two groups of hUC-MSCs were identified by real-time fluorescence quantiative PCR(RT-qPCR). RESULTS: The results of flow cytometry showed that hUC-MSCs obtained by the two methods both expressed high levels of CD73, CD90 and CD105, while lowly expressed CD31, CD45 and HLA-DR. The results of CCK-8 and CFU-F assay showed that the proliferation ability of hUC-MSCs obtained by explant culture method was better than those obtained by enzyme digestion method. The results of the triple lineage differentiation experiment showed that there was no significant difference in multilineage differentiation potential between the two grous of hUC-MSCs. The results of RT-qPCR showed that the mRNA expression levels of hematopoietic supporting factors SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in hUC-MSCs obtained by explant cultrue method were higher than those obtained by enzyme digestion method. CONCLUSION Clinical-grade hUC-MSCs with high expression levels of hematopoietic supporting factors were successfully cultured in an animal serum-free culture system.
Humans ; Mesenchymal Stem Cells/metabolism* ; Umbilical Cord/cytology* ; Cell Differentiation ; Female ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12/metabolism* ; Angiopoietin-1/metabolism* ; Vascular Cell Adhesion Molecule-1/metabolism* ; Stem Cell Factor/metabolism* ; Flow Cytometry ; Pregnancy

The interest in covalent drugs has resurged in recent decades, spurring the development of numerous specialized computational docking tools to facilitate covalent ligand design and screening. Herein, we present CarsiDock-Cov, a new paradigm distinguishing itself as the first deep learning (DL)-guided approach for covalent docking. CarsiDock-Cov retains the core components of its non-covalent predecessor, leveraging a DL model pretrained on millions of docking complexes to predict protein-ligand distance matrices, along with a dedicated-designed geometric optimization procedure to convert these distances into refined binding poses. Additionally, it incorporates several key enhancements specifically tailored to optimize the protocol for covalent docking applications. Our approach has been extensively validated on multiple public datasets regarding the docking and screening of covalent ligands, and the results indicate that our approach not only achieves comparably improved applicability compared to its non-covalent predecessor, but also exhibits competitive performance against various state-of-the-art covalent docking tools. Collectively, our approach represents a significant advance in covalent docking methodology, offering an automated and efficient solution that shows considerable promise for accelerating covalent drug discovery and design.

Gene regulation relies on the precise binding of transcription factors (TFs) at regulatory elements, but simultaneously detecting hundreds of TFs on chromatin is challenging. We developed cFOOT-seq, a cytosine deaminase-based TF footprinting assay, for high-resolution, quantitative genome-wide assessment of TF binding in both open and closed chromatin regions, even with small cell numbers. By utilizing the dsDNA deaminase SsdAtox, cFOOT-seq converts accessible cytosines to uracil while preserving genomic integrity, making it compatible with techniques like ATAC-seq for sensitive and cost-effective detection of TF occupancy at the single-molecule and single-cell level. Our approach enables the delineation of TF footprints, quantification of occupancy, and examination of chromatin influences on TF binding. Notably, cFOOT-seq, combined with FootTrack analysis, enables de novo prediction of TF binding sites and tracking of TF occupancy dynamics. We demonstrate its application in capturing cell type-specific TFs, analyzing TF dynamics during reprogramming, and revealing TF dependencies on chromatin remodelers. Overall, cFOOT-seq represents a robust approach for investigating the genome-wide dynamics of TF occupancy and elucidating the cis-regulatory architecture underlying gene regulation.
Transcription Factors/genetics* ; Humans ; Chromatin/genetics* ; Animals ; Binding Sites ; Mice ; DNA Footprinting/methods*

Objective To determine the knee joint cartilage thickness using different methods and explore the feasibility of mathematical statistical models of dataset for the prediction of cartilage thickness.Methods A total of 304 patients diagnosed as knee osteoarthritis(OA)combined with varus deformity and undergoing unilateral total knee arthroplasty at the Second Affiliated Hospital of Army Medical University from March 2023 to March 2024 were selected for the study.All patients had complete preoperative and postoperative clinical data.The healthy cartilage at four anatomical sites of patients,including the distal femur lateral condyle,lateral tibial plateau,posterior medial femoral condyle,and posterior lateral femoral condyle were selected,and the knee joint cartilage thickness was determined based on preoperative MRI analysis,robotic navigation system tracing,tissue section of surgical specimen and digital vernier caliper.The baseline indicators of demographics,disease and imaging ffor patients were collected to construct a dataset,and four models of linear regression analysis,principal component analysis,Least Absolute Shrinkage and Selection Operator(LASSO)regression analysis,and K-nearest neighbors(KNN)analysis were established for predicting the accuracy,determination coefficient(R2)and root mean square error(RMSE),and the regression equation for predicting cartilage thickness was established.Results The knee joint cartilage thicknesses determined by preoperative MRI analysis,robotic navigation system tracing,tissue section of surgical specimen had no statistically significant difference with that by digital vernier caliper(P>0.05).The predictive efficiencies of models of linear regression analysis,principal component analysis,and LASSO regression analysis for the knee joint cartilage thickness all failed to meet the expectations(R2<0.3,RMSE>0.03).The predictive effect of KNN model on the cartilage thickness of the distal femur lateral condyle and lateral tibial plateau was not ideal(R2=0.23,RMSE=0.29),while it had potential predictive value(accuracy=0.21,accuracy=0.15).Conclusion The prediction model of knee joint cartilage thickness based on individual parameters has certain scientificity,and the feasibility of KNN model is relatively high.However,due to insufficient sample size and unclear individual parameter weight,the efficiencies of the four established prediction models are not ideal,which fails to provide definite prediction equations.Therefore,the construction scheme of the prediction model still needs to be further optimized.

Objective To carry out quality inspection of the ultrasound soft tissue cutting hemostatic equipment to ensure its safety and effectiveness.Methods Five brands of ultrasound soft tissue cutting hemostatic equipment were selected and noted as test equipment A,test equipment B,test equipment C,test equipment D and test equipment E,which underwent quality inspection in terms of tip main amplitude,tip lateral amplitude,tip vibration frequency,excitation frequency,static electrical power and contact current based on YY/T 0644-2008 Ultrasonics-surgical systems—Measurement and declaration of the basic output characteristics,YY/T 1750-2020 Ultrasonic surgical equipmetn for soft tissue excision and hemostasia and GB 9706.1-2020 Medical electrical equipment—Part 1:General requirements for basic safety and essential performance.Results The test data of the five brands in terms of tip main amplitude,tip lateral amplitude,tip vibration frequency,excitation frequency,static electrical power and contact current met the technical requirements of YY/T 0644-2008,YY/T 1750-2020,GB 9706.1-2020.Conclusion The quality inspection of the ultrasound soft tissue cutting hemostatic equipment contributes to enhancing the accuracy and stability of the equipment and decreasing the risk during its clinical application.[Chinese Medical Equipment Journal,2025,46(10):49-53]

Objective To investigate the coagulation effect of a cold atmospheric plasma(CAP)jet device with helium as the working gas and to study its coagulation mechanism preliminarily.Methods A CAP jet device treatment group,a helium airflow treatment group,a hot air treatment group(60℃)and a natural coagulation group were formed according to the treatment modes of the blood samples,with 10 μL of blood samples involved in each group,in order to validate the coagulation effect of the CAP jet device in vitro;the coagulation mechanism of the CAP jet device was explored by its application to the treatment of anticoagulated whole blood,platelet-rich plasma and platelet-depleted plasma;the coagulation effect of the CAP jet device in vivo was verified with a mouse liver punctate hemorrhage model and a rabbit mesenteric hemorrhage model.Results The CAP jet device can significantly accelerate the coagulation of anticoagulated blood droplets,and the coagulation time of anticoagulated blood droplets in the CAP jet device-treated group was shortened from 28 min in the natural coagulation group to(23±1.56)s,with the difference statistically significant(P<0.05),and the CAP jet device treatment group gained advantages significantly over the helium airflow treatment group(P<0.05)and the hot air(60℃)treatment group(P<0.05)in coagulation-promoting effect;the procoagulant effect of the CAP jet device rose with the increase of platelet content in blood droplets,and the coagulation effect of platelet-rich blood droplets was significantly better than that of whole blood(P<0.05),while no coagulation was observed in platelet-poor droplets.The CAP jet device could rapidly stop hemostasis of punctate hemorrhage in mouse liver and mesenteric hemorrhage in rabbits without delayed hemorrhage occurring within 10 min,and no obvious structural abnormality of the liver and thermal damage of the tissue were found microscopically.Conclusion The CAP jet device plays procoagulant and hemostatic effects in vivo and in vitro,and its effect is not dependent on temperature and airflow evaporation effects and is considered to be related to platelet activation,with low thermal damage to living tissue.[Chinese Medical Equipment Journal,2025,46(6):20-27]