Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

Objective To study the effects of vision on human postural control and the connection mechanisms of the brain's functional network.Methods 15 healthy male adults were required to perform 30 s of balanced standing on both legs with eyes open and eyes closed.The center of pressure(COP)and electroencephalograph(EEG)were recorded during balance.The sample entropy(sample En)of the COP was calculated.The phase lag index(PLI)in θ-,α-,β-band of EEG was calculated to construct the brain functional networks,and the clustering coefficient(C),characteristic path length(L),and the criteria(σ)of the small-world network were calculated based on graph theory.Results During balanced standing on both legs,the SampleEn of the COPY with eyes closed was significantly higher than that with eyes open(P＜0.05).The mean value of PLI in the α-band under the eyes closed state was significantly higher than that under the eyes open state(P＜0.05).The C and σ values in the α-band under the eyes closed state were significantly higher than those under the eyes open state,and the L value was significantly lower than that under the eyes open state(P＜0.05).The frontal-central-parietal connectivity and the central-parietal connectivity strength in the α-band under the eyes closed state were significantly higher than those under the eyes open state(P＜0.05).The average PLI and C values in the α-band were moderately negatively correlated with the SampleEn of COPY (P＜0.05).The average PLI of the left prefrontal area,left parietal area,and left occipital area in the α-band under the eyes closed state had a moderate negative correlation with the SampleEn of COPY.The average PLI of the left central region and the right occipital area in the eyes-closed state was moderately negatively correlated with the SampleEn of COPY.Conclusions During the standing balance,when there is no visual input,the stability of body balance decreases,accompanied by enhanced brain network connectivity in α-band and the requirement for efficiency enhancement in information processing in the brain.The brain adopts different neural strategies when performing postural control under various visual conditions.

In this paper, we propose a multi-scale mel domain feature map extraction algorithm to solve the problem that the speech recognition rate of dysarthria is difficult to improve. We used the empirical mode decomposition method to decompose speech signals and extracted Fbank features and their first-order differences for each of the three effective components to construct a new feature map, which could capture details in the frequency domain. Secondly, due to the problems of effective feature loss and high computational complexity in the training process of single channel neural network, we proposed a speech recognition network model in this paper. Finally, training and decoding were performed on the public UA-Speech dataset. The experimental results showed that the accuracy of the speech recognition model of this method reached 92.77%. Therefore, the algorithm proposed in this paper can effectively improve the speech recognition rate of dysarthria.
Humans ; Dysarthria/diagnosis* ; Speech ; Speech Perception ; Algorithms ; Neural Networks, Computer

The hippocampus plays an important role in fear learning and memory processing.It is a key brain area in the pathogenesis of post-traumatic stress disorder (PTSD). Neuroimaging studies have confirmed that the hippocampal structure and functional connectivity of patients with PTSD are abnormal, but the changes in hippocampal subregions are still unclear.The results of brain structure studies showed that the cornu ammonis and dentate gyrus atrophy in adult PTSD patients and the symptom of re-experience may be related to pattern separation dysfunction caused by reduced dentate gyrus neurogenesis.Among children diagnosed with PTSD, there is no significant change found in cornu ammonis and dentate gyrus, while atrophy in presubiculum was observed, which could result in fear extinction and deficits in episodic memory.The alteration of hippocampal volume in PTSD may have a gender-specific lateralization phenomenon.The results of brain function studies show that the functional connectivity of hippocampal subregions in PTSD patients is selectively damaged, especially the connectivity with key brain regions in the default mode network is reduced.This article systematically reviews the structural and functional connectivity changes of hippocampal subregions in patients with PTSD from the perspective of neuroimaging, in order to promote the understanding of the pathogenesis of PTSD and identify the therapeutic targets of hippocampal subregions.

Objective To explore what kind of strategies should be adopted by the medical disciplines of comprehensive universities in China,taking into account and respect the particularity nature of medical science,inspiring innovative creation to build the First-Class disciplines.Methods Literature review and quantitative research were adopted in this paper.By reviewing published articles to better understand the special laws of medical disciplines and identify current development problems.Furthermore,the data from ESI,QS Ranking,and the Ministry of Education were collected to reveal problems and to propose strategies.Results The future development of Medicine disciplines possesses the characteristics of integration,technology dependence,heterogeneity,etc.In the new era of building world-class disciplines and first-class universities,compared with international first-class disciplines,peaks of medical disciplines in Chinese universities are still relatively scarce.The comprehensive university medical discipline should adhere to the principle of ‘connotative development’.In the process of construction,medical discipline should pay full attention to cross-integration,promote cross-disciplinary,adjust and optimize the former system.Strengthen the construction of new disciplines development to build medical disciplines with distinctive features.Optimize top-level design to foster disciplines peaks.Attach great importance to the construction of talents to build up high-level talent team with sustainable development ability.Emphasize on medical education to improve the quality of personnel training.Promote institutional innovation to activate the vitality of integration.Build an effective evaluation system to promote construction.Conclusions With the premise of fully respecting the special laws and characteristics,the medical discipline constructions of comprehensive universities should be guided by the future development model of medicine and clinical needs,and adhered to the ‘connotative development’.With the development of medical disciplines,the level of clinical diagnosis and treatment will be improved,the original innovation will be enhanced,as well as the social service capabilities of comprehensive universities,furthermore,the frontiers of scientific development and national strategic development needs will be effectively supported.

Objective: To investigate the risk factors of ventricular arrhythmias in patients with Brugada syndrome. Methods: Clinical data of 60 Brugada syndrome patients admitted in the department of cardiology of the First Affiliated Hospital of Nanjing Medical University from March 2003 to December 2016 were collected and retrospectively analyzed. The age at diagnosis was (43.2±13.1) years (0.6-83.0 years), 98.3% were males (n=59), and the patients were followed up to (92±41) months (12-169 months). The 12-lead surface electrocardiogram (ECG) recorded at the time of diagnosis and showing the highest type 1 ST elevation, either spontaneously or after provocative drug test, was used for the analysis. Patients were divided into ventricular arrhythmia (VA, n=12) group and non-ventricular arrhythmia (non-VA, n=48) group depending on the presence or absence of clinical VA event. The demographic data and ECG data of the 2 groups were compared, and the independent risk factors of VA events were analyzed by stepwise logistic regression. Results: Incidence of family history of sudden death (7/12 vs. 22.9% (11/48)) and percentage of type 1 ST elevation in the peripheral ECG leads (6/12 vs. 16.67% (8/48)) were significantly higher in VA group than in non-VA group (both P<0.05). Max Tpeak-Tend (Max-Tpe) interval ((144±53)ms vs. (110±16)ms) and dispersion of Tpe ((74±50)ms vs. (43±17)ms) were significantly higher in VA group than in non-VA group (both P<0.05). The area under receiver operating characteristic (ROC) curves for the Max-Tpe interval was 0.693 and Max-Tpe interval ≥140 ms was determined as an optimized cutoff point with increased risk of VA event, which had a sensitivity of 50.0%, a specificity of 98.0%, a positive predictive value of 85.7%, and a negative predictive value of 88.7% for predicting VA event. The ROC curves for the dispersion of Tpe was 0.775 and dispersion of Tpe ≥45 ms was determined as an optimized cutoff point for predicting VA event, which had a sensitivity of 91.7%, a specificity of 64.6%, a positive predictive value of 39.3%, and a negative predictive value of 96.9% for predicting VA event. In multivariate analysis, Max-Tpe interval ≥140 ms (OR=27.53, 95%CI 1.07-706.77, P=0.045) and family history of sudden death (OR=24.63, 95%CI 2.05-295.38, P=0.011) were found to be the independent risk factors of arrhythmic events. Conclusions Max-Tpe interval ≥140 ms and family history of sudden death are risk factors of VA event in included patients with Brugada syndrome.