Objective:To design a lung nodule detection algorithm based on the improved YOLOv7 model.Methods:Firstly, in the PAFPN structure, a lightweight upsampling operator CARAFE is introduced to improve the lung nodule detection accuracy. Then an enhanced small-scale detection layer is added to enhance the detection performance for small-target lung nodules, while the number of trained parameters can be reduced and the model complexity can be lowered. An enhanced small-scale detection layer is added to the YOLOv5 model algorithm while comparing it with the original YOLOv5 model algorithm, the original YOLOv7 model algorithm, and the improved YOLOv7 model algorithm in terms of the total loss of the training set of the improvement points, while ensuring that the parameter indexes remain unchanged. The original YOLOv7 model algorithm and the improved YOLOv7 model algorithm are used to process the 2 test set images and compare them with other classical lung nodule detection algorithms Mask R-CNN, YOLOv3, YOLOv5s and YOLOv7.Results:Compared with the original YOLOv5 model algorithm, the improved YOLOv5 model algorithm with the addition of an enhanced small-scale detection layer has a 1.3% increase in precision, a 3.5% increase in recall, a 3.1% increase in mean average precision (mAP), a 25.3% decrease in parameters amount, and a decrease in the complexity of the network; whereas the improved YOLOv7 model algorithm has a 1.8% increase in mAP, a 28.3% decrease in parameters amount, and the model complexity decreased by 5 G. Adding the enhanced small-scale detection layer with replacement of the special diagnostic fusion network as a lightweight up-sampling operator CARAFE algorithm can minimize the total loss of the model during the training process. The original YOLOv7 model algorithm is more accurate but still has missed detections and false positives. When reasoning about image 1, the original YOLOv7 model has a missed detection. And when reasoning about image 2, the original YOLOv7 model has a false positive. The improved YOLOv7 model is well improved in both missed detection and false positives. Compared with the classical model algorithm, the precision, recall, and mAP of the improved YOLOv7 model algorithm were 91.7%, 89.1%, and 93.5%, respectively.Conclusions:The improved YOLOv7 model has stronger feature expression ability and uses fewer parameters, which can effectively improve the detection precision of lung nodules.

Objective : To explore the expression of chemokine CXCL1 in proliferative infantile hemangioma (IH) , and to study the effect of exogenous CXCL1 on hemangioma stem cells (HemSCs) . Methods : Immunohistochemistry was used to explore the expression of CXCL1 in proliferative IH specimens.Primary HemSCs were isolated from IH tissues by CD133 magnetic beads.5 groups of CXCL1 with different concentrations(0,10,20,50 and 100 ng/ml) were co-cultured with HemSCs, and the effects of exogenous CXCL1 on HemSCs were studied by cell viability and migration experiments. Results : CXCL1 was expressed in the interstitial tissues of proliferative IH.The overall expression of CXCL1 in proliferative IH was low, but the expression of CXCL1 in the proliferative IH interstitial tissues was higher than that of the adjacent interstitial tissues.The CXCL1 positive area rate was(0.773±0.101)% in the tumor compared with(0.268±0.081)% in the adjacent tumor, and the difference was statistically significant(t=7.843,P<0.001).Exogenous CXCL1 promoted the proliferation of HemSCs, and there were statistical differences after adding different concentrations of CXCL1 to HemSCs for 24,48,and 72 h(F=14.610,P<0.001;F=14.430,P<0.001;F=5.388,P<0.01).But the exogenous CXCL1 did not affect the migration ability of HemSCs. Conclusion The expression of CXCL1 in proliferative IH interstitial tissues is higher than that in adjacent interstitial tissues, and exogenous CXCL1 promotes the proliferation of HemSCs.

Klebsiella pneumoniae(K.pneumoniae)is an important pathogen that can cause severe hospital-and community-acquired infections.To systematically investigate its methylation features,we determined the whole-genome sequences of 14 K.pneumoniae strains covering varying serotypes,multilocus sequence types,clonal groups,viscosity/virulence,and drug resistance.Their methy-lomes were further characterized using Pacific Biosciences single-molecule real-time and bisulfite technologies.We identified 15 methylation motifs[13 N6-methyladenine(6mA)and two 5-methylcytosine(5mC)motifs],among which eight were novel.Their corresponding DNA methyl-transferases were also validated.Additionally,we analyzed the genomic distribution of GATC and CCWGG methylation motifs shared by all strains,and identified differential distribution pat-terns of some hemi-/un-methylated GATC motifs,which tend to be located within intergenic regions(IGRs).Specifically,we characterized the in vivo methylation kinetics at single-base resolu-tion on a genome-wide scale by simulating the dynamic processes of replication-mediated passive demethylation and MTase-catalyzed re-methylation.The slow methylation of the GATC motifs in the replication origin(oriC)regions and IGRs implicates the epigenetic regulation of replication initiation and transcription.Our findings illustrate the first comprehensive dynamic methylome map of K.pneumoniae at single-base resolution,and provide a useful reference to better understand epigenetic regulation in this and other bacterial species.

The rapid spread of carbapenemase-producing Klebsiella pneumoniae(cpKP)poses seri-ous threats to public health;however,the underlying genetic basis for its dissemination is still unknown.We conducted a comprehensive genomic epidemiology analysis on 420 cpKP isolates col-lected from 70 hospitals in 24 provinces/autonomous regions/municipalities of China during 2009-2017 by short-/long-read sequencing.The results showed that most cpKP isolates were categorized into clonal group 258(CG258),in which ST11 was the dominant clone.Phylogenetic analysis revealed three major clades including the top one of Clade 3 for CG258 cpKP isolates.Additionally,carbapenemase gene analysis indicated that blaKPC was dominant in the cpKP isolates,and most blaKPC genes were located in five major incompatibility(Inc)groups of blaKPC-harboring plasmids.Importantly,three advantageous combinations of host-blaKPC-carrying plasmid(Clade 3.1+3.2-IncFⅡpHN7A8,Clade 3.1+3.2-IncFⅡpHN7A8:IncR,and Clade 3.3-IncFⅡpHN7A8:InCpA1763-KPC)were identified to confer cpKP isolates the advantages in both genotypes(strong correlation/coevolution)and phenotypes(resistance/growth/competition)to facilitate the nationwide spread of ST11/CG258 cpKP.Intriguingly,Bayesian skyline analysis illustrated that the three advanta-geous combinations might be directly associated with the strong population expansion during 2007-2008 and subsequent maintenance of the population of ST11/CG258 cpKP after 2008.We then examined drug resistance profiles of these cpKP isolates and proposed combination treatment regimens for CG258/non-CG258 cpKP infections.Thus,the findings of our systematical analysis shed light on the molecular epidemiology and genetic basis for the dissemination of ST11/CG258 cpKP in China,and much emphasis should be given to the close monitoring of advantageous cpKP-plasmid combinations.

Objective: To report the effects of operative treatment of Sneppen Ⅴ talus fracture through the approach for malleolus medialis Ⅴ osteotomy plus hollow compression screw fixation. Methods: From January 2015 to January 2019, 16 patients with Sneppen Ⅴ talus fracture were treated at Department Ⅱ of Hand & Foot Microsurgery, The Second Affiliated Hospital to Inner Mongolia Medical University. They were 14 men and 2 women with a mean age of 38.4 years (range, from 20 to 55 years). All fractures were fixed with hollow compression screws through the approach for malleolus medialis Ⅴ osteotomy. The ankle and hindfoot functional scoring system developed by American Orthopaedic Foot and Ankle Society (AOFAS) was used to evaluate the clinical outcomes. Results: All patients were followed up for a mean time of 12.6 months (range, from 6 to 30 months). The mean operation time was 68.4 minutes (range, from 52 to 96 minutes); the mean amount of hemorrhage during operation was 96.8 mL (range, from 48 to 122 mL); the mean period of bone union was 4.8 months (range, from 3 to 8 months). The postoperative mean AOFAS score was 75.3 points (range, from 43 to 91 points). Complications occurred in 4 cases, including one case of talus ischemic necrosis, one case of partial talus ischemic necrosis accompanied by tibial arthritis, one case of subtalar arthritis, and one case of combined tibial, talar and subtalar arthritis. All incisions obtained primary healing, with no complications like infection, screw breakage, delayed union or nonunion. Conclusion Operative treatment of Sneppen Ⅴ talus fracture through the approach for malleolus medialis Ⅴ osteotomy plus hollow compression screw fixation can provide sufficient operative exposure to facilitate reduction and fixation of the talus fracture so that the ischemic necrosis of the talus and traumatic arthritis can be effectively reduced.

Objective To study the transcriptional regulation of vp1667 by H-NS in Vibrio parahaemolyticus.Methods Total RNAs were extracted from Δhns and WT strains.Quantitative RT-PCR was carried out to calculate the transcriptional variation of vp1667 between Δhns and WT.Primer extension assay was also employed to detect the transcription start site and the promoter activity (i.e.the amount of primer extension products) of vp1667 in Δhns and that in WT.The promoter DNA region of vp1667 was amplified, purified, and cloned into the corresponding restriction endonuclease sites of pHRP309 that harbors a gentamicin resistance gene and a promoterless lacZ reporter gene.The recombinant pHRP309 plasmid was transformed into Δhns and WT, respectively, while β-galactosidase activity in cellular extracts was measured using a β-galactosidase enzyme assay system.The over-expressed His-H-NS was purified under native conditions with nickel loaded HiTrap Chelating Sepharose columns.The electrophoretic mobility shift assay (EMSA) and DNaseⅠ footprinting were then applied to analyze the DNA-binding activity of His-H-NS to vp1667 promoter region in vitro.Results and Conclusion The primer extension assay detected one transcription start site for vp1667, which was located at 28 bp upstream of vp1667, and its transcribed activity was under the negative control of the H-NS.The EMSA and DNaseⅠ footprinting assay results showed that His-H-NS was unable to bind to the promoter-proximal DNA region of vp1667, suggesting that H-NS indirectly inhibits the transcription of vp1667.

Objective To characterize the resistance mechanisms of a clinical Shigella sonnei strain harboring blaCTX-M-55 .Methods A double-disk synergy test was conducted to detect ESBL.Antibiotic resistance genes were determined by PCR followed by amplicon sequencing.Conjugation experiments were performed to verify the transferability of the plasmids carrying ESBL genes.The minimum inhibitory concentration values were tested using VITEK 2.The transposition unit was confirmed by DNA sequencer,and the transcriptional start site was identified using primer extension assay.Results Strain #1083 produced CTX-M-55,which was encoded by plasmid p1083-CTXM that could be transferred into E.coli through conjugation experiments to confer corresponding antibiotic resistance to the transconjugant #1083-EC600.The transposition unit mediating the transfer of blaCTX-M-55 was ISEcp1-blaCTX-M-55 -Δorf477.ISEcp1 offered strong promoter regions for the resistance genes,facilitating their expressions.Besides,the expressions were constant,not induced by antibiotics.Conclusion BlaCTX-M-55 on plasmids is the major resistance genes for strain #1083.Their expressions and spread are mediated by the insertion sequence ISEcp1.

Objective To characterize the whole-sequence of plasmid pB557-NDM isolate from Enterbacter cloacae and elaborate its antibiotic-resistant mechanisms .Methods Antibiotic resistance genes were determined by PCR , followed by amplicon sequencing .The activity of class A/B/D carbapenemases was determined by modified Carba NP test .Conjugation experiments were performed to verify the transferability of plasmid pB 557-NDM.The minimum inhibitory concentration (MIC) values of bacterial strains were tested using VITEK 2.The genetic structure, mobile elements and antibiotic-resistant mechanisms of transferable plasmid pB 557-NDM were determined by a whole genome sequencing method .Results The modified CarbaNP test showed that B557 and B557-EC600 had class B carbapenemase activity , and that the blaNDM was carried by plasmid pB557-NDM.This plasmid could be transferred into E.coli through conjugation experiments and therefore could confer corresponding antibiotic resistances to the transconjugant B 557-EC600.Plasmid pB557-NDM was an IncA/C2 plasmid, whose total length was 141.65 kb, and the GenBank accession number was KX786648.It had two inserted regions.One was the blaCMY-6 region where the blaCMY gene was carried by a transposition unit IS Ecp1-blaCMY , the other was the blaNDM-1 region which consisted of a ΔTn1696-In46-rmtC-ISKpn14-ΔTn125 complex structure.Conclusion The production of plasmid pB557-NDM in strain B557 contributes most to its high resistance to many antibiotics .The blaNDM-1 gene is carried in a trancated transposition ΔTn125.

Objective To investigate the surgical reparation of large coloboma raw surface after facial tumour resection in elderly patients.Methods According to the position and characteristics of tumor as well as the age and tolerance of the patients, full thick skin graft, the skin flaps with subcutaneous pedicle and free skin flap were designed and used in the reparation.Results 24 cases with large coloboma raw surface (5 cm×7 cm-12 cm× 16 cm)were treated by the utilization of three approaches after tumor resection.The large coloboma raw surface in all patients achieved the healing with satisfactory appearance.Conclusions After facial tumour resection, the large coloboma raw surface can be repaired by using the skin graft, skin flaps after tumor resection or free skin flap if designed reasonably.The procedure of operation is simple and the therapeutic effect is satisfactory.

Objective To study the distribution and molecular characteristics of Vibrio parahaemolyticus(VP) in patients with a‐cute diarrhea ,and provide a scientific basis for the prevention and control of VP infection .Methods From 2010 to 2014 ,62 VP iso‐lates were collected from patients with acute diarrhea ,for serotyping and virulence gene (tdh and tdh) detection of VP .Molecular characteristics analysis was carried out by using multi‐locus sequence typing (MLST) .Results 7 different serotypes were found from the 62 isolates .O3∶K6 was the most common serotype of VP ,accounting for 74 .19% (46 isolates) ,followed by O4∶K68 (6 isolates) .Tdh gene was the mainly virulence gene ,with a percentage of 95 .16% (59 isolates) ,only three isolates were trh positive . 7 STs were found through MLST analysis of 62 VP isolates ,among which ,ST3 was the most important type ,accounted for 85 .50%(53 isolates) .Conclusion O3∶ K6 serotype VP was the most prevalent type .Tdh gene is the most important virulence gene of WP .ST3 was the the dominant epidemic type .