The gene smu. 776 encodes a possible S-adenosylmethionine-dependent methyltransferase of 385 residues in Streptococcus mutans, a primary pathogen for human dental caries. The DNA fragment of smu.776 was cloned into pET28a and expressed in good amount from the E. coli strain BL21 (DE3). Smu.776 protein was purified to homogeneity in a two-step procedure ofNi2+ chelating and size exclusion chromatography. Crystals were obtained by hanging-drop vapor diffusion method and diffracted to 2.0 (A) resolution.The crystal belongs to orthorhombic space group C2 with cell dimension of a=168.47 (A), b= 50.66 (A), c=53.96 (A), β=104.22°. The asymmetric unit is expected to contain one molecule with solvent content of 51.3%.

Smu_195c is a protein with 86 amino acids in Streptococcus mutans, a primary pathogen for human dental caries. The specific function of Smu_195c is still unknown and there are no conserved domains in it. In order to find out its function, the gene encodes Smu_195c was cloned and expressed in E. coli as N-terminally 6*His tagged recombinant protein. Two crystal forms were obtained by the hanging drop method. Form Ⅰ belongs to space group P6122 or P6522 with the unit cell parameters a = b = 62.93 (A), c= 90.63 (A), γ=120° and form Ⅱ belongs to the space group P41212 or P43212 with the unit cell parameters a =b=57.97 (A), c = 103.51 (A).Crystals from the protein with His-tag belong to form Ⅰ, however, crystals from the protein without His-tag belong to both.

Smu. 260 encodes a putative protein of 200 residues in Streptococcus mutans, a primary pathogen for human dental caries. Smu. 260 was cloned into expression vector pET28a and expressed in good amount trom the E. coli strain BL21 (DE3). Smu.260 protein was purified to homogeneity in a two-step procedure of Ni2+ chelating and size exclusion chromatography. The purified protein exists in two forms, a dimer form about 46 ku with yellow color and a tetramer form without apparent color. Crystals were obtained from the dimer protein by hanging-drop vapor-diffusion method. The crystals diffracted to about 2.3 A resolution and belong to orthorhombic space group P212121 with cell dimensions of a = 89.88A, b = 90.91 A, c = 105.17 A. The asymmetric unit is expected to contain two dimers with solvent content of 53%.

The real-time and wireless mobile has become the trend of electrocardiogram (ECG) monitoring system for atrial fibrillation (AF). At present, the ECG with multi-leads (12 leads) is needed by most of AF signal extraction algorithms in order to extract effective AF waves. However, it is not very convenient for patients' movements in a multi-lead ECG monitoring system. Although the traditional template matching method is for single-lead ECG extraction, it is less robust than blind source extraction algorithm, and is affected severely by noise. In view of this,we put forth a new real-time algorithm for extracting AF from the singlelead ECG, using non-stationary heartbeat series during AF to extend dimension (segmentation), and then applying a blind source extraction algorithm to extract the effective AF signal. Experiment results showed that this method could be used to extract AF signal effectively from a single-lead ECG data. Therefore, it is suitable to apply this method to Wireless Monitoring System using single-lead ECG.
Algorithms ; Atrial Fibrillation ; physiopathology ; Electrocardiography ; methods ; Humans ; Signal Processing, Computer-Assisted

Deoxycytidylate (dCMP) deaminase is an enzyme belonged to dCMP cyt deam family. The dCMP deaminase from Streptococcus mutans UA159 was cloned and expressed in E. coli, and purified to homogeneity. The FPLC size exclusion chromatography analysis reveals that the S. mutans dCMP deaminase forms hexamer in solution. The protein was crystallized using hanging drop vapour-diffusion method and diffracted to a resolution of 3.1 (A). The diffraction data were collected at BSRF beamline3W1A. The crystals belong to P213 space group, with unit cell parameters a = b = c = 113.2(A), α =β = γ = 90°. Assuming there are two subunits per asymmetric unit, the Matthews coefficient is 3.6 (A)3 ·Da-1. This is the first crystallization report of the wild-type deoxycytidylate deaminase.

Deoxycytidylate (dCMP) deaminase is an enzyme belonged to dCMP cyt deam family. The dCMP deaminase from Streptococcus mutans UA159 was cloned and expressed in E. coli, and purified to homogeneity. The FPLC size exclusion chromatography analysis reveals that the S. mutans dCMP deaminase forms hexamer in solution. The protein was crystallized using hanging drop vapour-diffusion method and diffracted to a resolution of 3.1 ?. The diffraction data were collected at BSRF beamline 3W1A. The crystals belong to P213 space group, with unit cell parameters a = b = c = 113.2 ?, ? = ? = ? = 90?. Assuming there are two subunits per asymmetric unit, the Matthews coefficient is 3.6 ?3?Da-1. This is the first crystallization report of the wild-type deoxycytidylate deaminase.

Objective:To determine whether the early stage platelet count can predict the outcome of peritoneal dialysis-associated peritonitis (PDAP).Methods:A retrospective cohort study was conducted by selecting PDAP patients who were hospitalized in the First People's Hospital of Foshan from January 2012 to January 2019. According to the final treatment outcome, the patients were divided into cured group and withdrawn group. The withdrawn group included patients who transferred to hemodialysis or died. Basic data on demography, blood routine examination, peritoneal fluid, biochemical indicators were compared between the two groups. Logistic regression analysis was used to analyze the withdrawn risk factors of PDAP.Results:There were 180 patients included in the study, including 112 cases in the cured group and 68 cases in the withdrawn group. Compared with the cured group, there were older age [(53.38±14.17) years old vs (48.41±13.04) years old, t=2.407, P=0.017], longer age of dialysis [(49.20±26.05) months vs (30.36±32.97) months, t=4.034, P<0.001], longer hospital stay [(23.88±11.50) d vs (17.80±3.95) d, t=5.133, P<0.001] and higher platelet count [(285.55±107.23)×10 9/L vs (234.90±74.03)×10 9/L, t=3.450, P=0.001], lower serum albumin [(31.72±7.47) g/L vs (35.40±4.93) g/L, t=-3.972, P<0.001] in the withdrawn group. Multivariate logistic regression analysis showed that longer dialysis age ( OR=1.012, 95% CI 1.007-1.024, P=0.015) and higher platelet count ( OR=1.013, 95% CI 1.004-1.026, P=0.008) were independent risk factors, and higher serum albumin ( OR=0.941, 95% CI 0.896-0.988, P=0.005) was an independent protective factor of withdrawal from peritoneal dialysis in PDAP patients. Conclusions:The long dialysis age, early high platelet count are independent risk factors and high serum albumin level is an independent protective factor for withdrawal from peritoneal dialysis in PDAP patients.

Objective:To identify the relationship between exposure to mobile phones and other electronic products and the ability development in children.Methods:Retrospective study.A total of 218 children aged 0.5-6.0 years presented to the Department of Health Care, Beijing Children′s Hospital, Capital Medical University form September 2019 to June 2020 for developmental examination were included.Those with nervous system, mental system diseases, endocrine system diseases and premature children were excluded.Their development was evaluated and the information about exposure to mobiles phones and other electronic products were collected. Chi- square test and Fisher′ s exact probability method were used to analyze the relationship between the exposure to mobile phones and other electronic products and the ability development in children.The influencing factors of children′s development in various fields were analyzed by the binary Logistic regression. Results:Abnormal fine movements of children aged 0.5-0.9 years were related to the latest time every night of exposure ( P<0.05). Abnormalities of adaptability, language and social self-care in children aged 1.0-2.9 years and abnormality of language in children aged 3.0-5.9 years were correlated with the number of hours of daily exposure (all P<0.05). Abnormalities of language and social self-care in children aged 1.0-2.9 years and abnormalities of adaptability, language and social self-care in children aged 3.0-5.9 years were correlated with the purposes of exposure (all P<0.05). Binary Logistic regression analysis indicated that the children′s gross motor was affected by the number of hours of daily exposure ( OR=1.868, P<0.05). The children′s fine motor movements were affected by mother′s educational level and the latest time every night of exposure ( OR=1.722, 2.355, all P<0.05). The children′s adaptability was affected by mother′s educational level, child caregivers, the number of hours of daily exposure and the latest time every night of exposure ( OR=1.711, 2.866, 1.895, 1.650, all P<0.05). The children′s speech was affected by the number of hours of daily exposure, the latest time every night of exposure, and the purposes of exposure (telephone or video phone, early education or study)( OR=2.348, 1.806, 0.328/0.350, all P<0.05). The children′s social interaction and self-care delay were affected by mother′s educational level, the number of hours of daily exposure and the purposes of exposure (telephone or video phone, early education or study)( OR=1.647, 2.678, 0.307/0.363, all P<0.05). Conclusions:The adverse effects of exposure to mobile phones and other electronic products on children should be well concerned.The exposure time of developing young children should be strictly controlled to prevent the adverse effects on the nervous system and development in children.For children who were already affected, relevant habits and behaviors should be timely corrected to avoid irreversible damages.