Objective: To compare the biological characteristics of human induced pluripotent stem cell-derived platelet exosomes (hiPSC-Plt-Exos) with those of conventional apheresis platelet exosomes (Plt-Exos), specifically focusing on their differential abilities to enhance the proliferation and migration of human umbilical cord mesenchymal stem cells (hUC-MSCs). Methods: Exosomes were isolated from hiPSC-derived Plt and apheresis Plt concentrate using size exclusion chromatography. These exosomes were then characterized through nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western blotting. Co-culture experiments into hUC-MSCs were conducted with hiPSC-Plt-Exos and apheresis Plt-Exos, respectively. Their effects on the proliferation and migration of hUC-MSCs were assessed via cell proliferation assays and scratch tests. Results: hiPSC-Plt-Exos and apheresis Plt-Exos exhibited comparable particle sizes, morphological features (such as the characteristic cup-shaped structure), and surface markers (including CD9 and HSP70). Notably, hiPSC-Plt-Exos demonstrated a significantly greater ability to enhance the proliferation and migration of hUC-MSCs compared to apheresis Plt-Exos (P<0.05). These differences provide critical comparative data for their application in various clinical contexts. Conclusion: This study establishes a theoretical foundation for developing precise therapeutic strategies based on hiPSC-Plt-Exos. Furthermore, it underscores the necessity of selecting the appropriate type of exosomes according to the specific disease microenvironment to achieve optimal therapeutic outcomes.

Objective To establish a method for detecting the 2019 novel coronavirus subgenomic RNA(sgRNA),and evaluate the performance of the established method.Methods Primers and probes were designed according to the subgenomic sequence of the 2019 novel coronavirus,and a reverse transcription PCR method for sgRNA detection was established.The established method was optimized,including the concentration and propor-tion of primers and probes,extension temperature,reaction volume and template amount.The performance of the method was evaluated,including the limit of detection,sensitivity,specificity and repeatability.sgRNA and genomic RNA(gRNA)were detected in clinical samples,and the results were analyzed.Results In this study,an RT-PCR method for the detection of sgRNA of the 2019 novel coronavirus was established.The limit of detection of this method was 100 copies/mL,and the detection results of common pathogens were negative.The CV of sgRNA in high,medium and low concentration samples were less than 5%.sgRNA was positive in 115 suspected 2019 novel coronavirus infected patients(115/330,34.85%).When the Ct value of gRNA-N was less than 30,the positive rate of sgRNA was 100.00%.When the Ct value of gRNA-N was in the range of 30-32,the positive rate of sgRNA was 68.75%.When the Ct value of gRNA-N was in the range of 32-35,the positive rate of sgRNA was 44.44%.When the Ct value of gRNA-N was greater than 35,the sgRNA was negative.Conclusion The RT-PCR method for the detection of sgRNA of the 2019 novel coronavirus was established,and the detection method was sensitive,specific and reproducible.

Magnetic particles(MPs)are widely present in the environment,with high prevalence and complex sources.During the past decade,with the rapid development of separation techniques and detection methods for MPs,exogenous MPs have been found to be present in different parts of human body.Especially,the presence of MPs in human brain and blood has led to a high level of concern about their health risks,as the potential association with the development of neurodegenerative diseases such as Alzheimer's disease.Therefore,analysis of MPs in environmental and biological media is an important basis for understanding their physicochemical properties,investigating their biogeochemical cycling processes,and assessing their environmental and health risks.Here,the occurrence of MPs in different environmental media and biological samples were systematically summarized.The separation methods,characterization methods,qualitative and quantitative analysis methods,and source apportionment techniques of MPs were also reviewed.Finally,the future challenges in the development of analytical techniques for MPs were discussed.

Objective:To analyze the biological characteristics, phylogenic features and clinical significance of SQ219 and SQ220 isolated from clinical sputum and midstream urine specimens.Methods:The culture and biochemical characteristics of the two strains were observed. VITEK2 System, drug sensitivity testing and MALDI-TOF mass spectrometry were used for bacterial identification. Phylogenetic analysis based on 16S rRNA and core genome was performed. The average nucleotide identity (ANI) based on whole genome sequences was calculated.Results:SQ219 and SQ220 were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and non-motile bacteria. Their optimum growth was observed in NaCl-free medium at 30℃ and pH7. Flexirubin-type pigments were produced by SQ220 on Colombia blood agar, but not by SQ219. Both SQ219 and SQ220 were resistant to aztreonam, amikacin, tobramycin and colistin, which was consistent with the drug resistance phenotype of genus Chryseobacterium. The genome sequences of SQ219 and SQ220 were 5.08 Mb and 4.80 Mb in length, and the G+ C contents were 36.72% and 36.36%, respectively. Both strains carried β-lactam resistance gene ( blaCGA). 16S rRNA phylogenetic analysis showed that SQ219 and SQ220 were closely related to Chryseobacterium gambrini DSM18014 T with the similarities of 98.93% and 98.36%, respectively. Core genome phylogenetic analysis revealed that SQ219 and SQ220 were highly homologous to Chryseobacterium gambrini DSM18014 T. However, the ANI values between the two strains and Chryseobacterium gambrini DSM18014 T were 92.49% and 93.27%, respectively, below the threshold for prokaryotic species identification. Conclusions:Based on the phenotypic and phylogenetic data, SQ219 and SQ220 represent a novel species of the genus Chryseobacterium. This study would help promote the understanding of the evolution of Chrysobacterium and provide reference for the identification of new species of Chrysobacterium.

The 2019 novel coronavirus (2019-nCoV) is a newly discovered pathogen in 2019. The coronavirus disease (COVID-19) has spread around the world and has greatly affected global health and the world economy. It is a positive-sense single-stranded RNA virus, which generates subgenomic RNA from discontinuous transcription of the replication-transcription complex (RTC). This discontinuous transcription is regulated by transcriptional regulatory sequences/elements, produced by switching templates on genomic RNA. At present, the detection methods of subgenomic RNA include the next generation sequencing, nanopore sequencing, reverse transcription dropletdigital polymerase chain reaction, reverse transcription real-time quantitative polymerase chain reaction, etc. Subgenomic RNA is produced only when the virus infects cell, so it may be a novel marker for viral replication.

Objective To measure and compare the lateral posterior tibial slope (LPTS) , medial posterior tibial slope ( MPTS) and tibial torsion angle ( TTA) between the patients of recuiTent patellar dislocation and the heathy people, and to analyze the correlation between LPTS, MPTS and TTA and the risk factors of recuiTent patellar dislocation. Methods A total of 33 patients (44 knees) with recuiTent patellar dislocation in our hospital from July 2019 to June 2021 were selected and listed as the stud)' group. Twenty-three subjects (46 knees) who were suspected iliac vascular and lower limb vascular diseases during the same period were selected and listed as the control group. All the enrolled researchers had fulllength CT scans date of the lower limbs. Three-dimensional models were reconstructed using Mimics 21. 0 software and then imported into 3-matic software. The LPTS, MPTS and TTA were measured and compared between the two groups. Results In the study group, the LPTS, MPTS and TTA were (7. 69} 1. 42) ° , ( 10. 06} 1. 71) ° , ( 36. 42}8. 13 ) ° , respectively while the control group, the LPTS, MPTS and TTA were ( 8. 42 } 1. 65 ) ° , ( 10. 44 } 0. 86 ) ° , ( 25. 77} 3. 90 ) ° , respectively. There were no signiiicant differences in the LPTS, MPTS and TTA between different genders and sides both in the stud)' group and the control group ( P > 0. 0 5 ) . Compared with the control group, the LPTS in the stud)' group was smaller, and the difference was statistically significant (P<0. 0 5 ) . There was no statistically significant difference between the stud)' group and the control group in the MPTS (P>0. 05). Compared with the control group, the TTA in the stud)' group was higher, and the difference was statistically significant (P< 0. 0 5 ) . Compared with the control group, the LPTS and MPTS in the study group were significant asymmetry, and the difference was statistically significant ( P < 0 . 0 5 ). Conclusion The lateral posterior tibial slope of patients with recurrent patellar dislocation is significantly smaller than that in the healthy people, while there is no significant difference in the medial posterior tibial slope; The tibial torsion angle of patients with recurrent patellar dislocation is significantly larger than in the healthy people; The lateral posterior tibial slope and tibial torsion angle have certain correlation with recurrent patellar dislocation, which can conduct the diagnosis of recurrent patellar dislocation.

【Objective】 To optimize the existing spin-EB method and promote human induced pluripotent stem cells (hiPSCs) differentiate into megakaryocytes (MKs). 【Methods】 In this study, the initial inoculation amount of hiPSCs was increased from 3 500 cells/well to 8 000 cells/well, and the size of EB was increased. By observing the generation time of EB- hematopoietic cells during differentiation, and detecting the proliferation of CD34⁺ hematopoietic progenitor cells and CD41⁺ MKs in different stages, it was studied whether the optimized scheme could promote the differentiation of hiPSCs into hematopoietic progenitor cells(HPCs) and MKs. 【Results】 By increasing the initial inoculation amount of hiPSCs and the size of EB, the differentiation of hiPSCs into HPCs and MKs and the cell production efficiency can be promoted. 【Conclusion】 Our research describes an optimized and repeatable differentiation method, which can produce hematopoietic progenitor cells and mature MKs from hiPSCs in a relatively short time with higher yield. It is of great clinical significance and broad scientific research prospect to continuously optimize the culture scheme of hiPSCs differentiation to produce MKs and platelets in vitro, and to promote large-scale platelet generation in vitro in transfusion medicine.

We have adopted various smart tools and applied multiple teaching models to smoothly carry out our on-line teaching. Aiming at encouraging students' self-learning and independent thinking, the first task is to cultivate students' self-learning ability and independent thinking way of clinical microbiology. Our online teaching model is based on the asynchronous small private online course (SPOC) of the Chinese University MOOC, the core part of our teaching model, and supplemented by the Sojump questionnaire test and WeChat, the inter-action channels among teachers and students. All of these build up an integrated teaching system which fully embodies the "student-oriented" teaching concept and pushes forward the promotion and application of online teaching in college specialized courses.

Objective:To evaluate the hemostatic efficacy of N-carboxyethylchitosan fiber gauze (numbered NWL-K) in a leporine bleeding wounds of intraperitoneal parenchymal visceral.Methods:Sixty New Zealand rabbits were divided into two groups according to the randomized digital number method, with 30 rabbits per group. The leporine bleeding models of hepatic or splenic wound were made respectively. The two groups were subdivided into three groups: common gauze group, SURGICEL group and NWL-K group, with 10 rabbits per group. By analyzing the weight of excised liver tissue and amount of bleeding, the model stability was measured. The time to hemostasis and bleeding score in each group were analyzed every (20±5)seconds after compression for 30 seconds in the hepatic bleeding models or every (30±5)seconds after compression for 3 minutes in the splenic bleeding models. The adhesion between wound and gauze was evaluated at the same time.Results:There was no significant difference in the weight of excised liver tissue and amount of bleeding when the hepatic or splenic bleeding models were made ( P>0.05). It showed that the model was made stably and the hemostasis experiment would not be affected. In the splenic wound model experiment, the time to hemostasis was 255(233, 300)seconds in SURGICEL group and 210(180, 248)seconds in NWL-K group, both of which were significantly shorter than 465(383, 660)seconds in common guaze group ( P<0.05). NWL-K achieved shorter time to hemostasis than SURGICEL ( P<0.05). In the hepatic wound model experiment, the time to hemostasis was 90(85, 110)seconds in SURGICEL group and 70(70, 95)seconds in NWL-K group, both of which were significantly shorter than 250(225 290)seconds in common gauze group ( P<0.05). In the splenic wound model experiment, the bleeding score in NWL-K group and SURGICEL group decreased faster than that in common gauze group ( P<0.05). The difference of bleeding score was significant between NWL-K group and SURGICEL group at 180 seconds ( P<0.05). In the hepatic wound model experiment, the bleeding score in NWL-K group and SURGICEL group decreased faster than that in common gauze group at 50 seconds, 70 seconds and 90 seconds ( P<0.05). The bleeding score in common gauze group and NWL-K group showed significant difference at 30 seconds, 110 seconds and 130 seconds ( P<0.05). For the adhesion evaluation, both the water-absorbency and adhesion to tissue of NWL-K were better than common gauze and SURGICEL. Conclusions:For hepatic and splenic bleeding wounds, compared with other types of gauze, the application of NWL-K can effectively shorten the time to hemostasis and reduce the blood loss. The NWL-K shows high water-absorbency and firm adhesion to bleeding wound.

ObjectiveQuorum-sensing (QS) and small regulatory RNA (sRNA) play key regulatory roles in many signaling cascades of Pseudomonas aeruginosa. To investigate whether sRNA is involved in P. aeruginosa QS system, screening QS system-related sRNA, and to construct sRNA overexpression and deletion strains of Pseudomonas aeruginosa for further study of sRNA function.MethodsSRNA associated with the QS system was screened by qPCR and RNA-sequencing (RNA-seq). The target gene were amplified by PCR and inserted into the overexpression vector pROp200 or the homologous recombination vector pGSM-MR, respectively. The connection reaction solution of pROp200-sRNA and pGSM-ΔsRNA was transformed into Escherichia coli DH5a and SM10lp, respectively. The recombinant vectors were identified by PCR. The pROp200-sRNA was transformed into PAO1 by heat shock method, and the pGSM-ΔsRNA was transferred from SM10lp to PAO1 by conjugation. SRNA overexpression and deletion strains were identified by PCR, DNA sequencing and qPCR, the determination of the growth curves and the pyocyanin levels of strains.ResultsFive QS -associated sRNA P26, P5316.1, P30, P34 and AmiL were successfully screened by RNA-seq and qPCR. PCR, DNA sequencing and qPCR showed that sRNA of AmiL, P30 and P34 overexpression and knockout were successful. Compared with wild-type strain, sRNA overexpression and knockout had no significant effect on bacterial growth curve. It were notably that overexpression of AmiL and P30 inhibited and increase the production of pyocyanin, respectively (P<0.01), while deficiency of AmiL and P30 in the genome resulted in significantly increase and decrease of pyocyanin, respectively (P<0.01). Overexpression and deletion of P34 had no significant effect on pyocyanin synthesis (P>0.05).ConclusionThe sRNA overexpression and deletion strains have been successfully constructed and can be used to study the regulatory relationship between sRNA and QS systems, and to further functional study.