ABSTRACT
Objective To investigate the effects of noise from the subway cars on the preferred listening volumes using different kinds of earphones.Methods A total of 75 subjects with normal hearing were investigated to listen the same song wearing 4 kinds of earphones: insert earphones, intra-concha earphones, supra-concha earphones, and circumaural earphones, in the semi-anechoic background and inside the Line 7 subway-cars of the Beijing subway (the mean of LAeq,1s is 80.3 dB A and then selected personally preferred listening volumes.The effects of noise in the subway cars and earphone types on the preferred listening volumes were then analyzed.Results Inside subway-cars, the preferred listening levels using insert earphones, intra-concha earphones, supra-concha earphones, circumaural earphones were 76.6±4.7, 84.3±5.0, 82.3±4.2, and 80.8±4.2 dB A, respectively.The levels were respectively 65.5±6.8, 71.9±7.1, 69.5±7.5, 67.9±7.3 dB A for those in the semi-anechoic background.The preferred listening levels increase more than 10 dB averagely when stepped into noisy subway-cars background from silent background.According to the threshold levels stipulated in the WHO, to avoid hearing impairment, the daily noise exposure duration should not exceed 134 mins when exposed to subway-cars noise and the duration should not exceed 315, 54, 85, and 120 mins respectively when wearing those 4 kinds of earphones in subway-cars.Conclusion The noise and earphones types have great effects on the preferred listening volumes.The noise exposure levels in the ear canal wearing earphones with good sound insulation and listening at highly increased volume may be lower than that without earphones.
ABSTRACT
<p><b>OBJECTIVE</b>To develop a high-throughput rapid method for Vibrio (V.) cholerae molecular typing based on Melting Curve-based Multilocus Melt Typing (McMLMT).</p><p><b>METHODS</b>Seven housekeeping genes of V.cholerae were screened out, and for each gene, the specific primers were designed for correspondent genes as well as 4 probes covering polymorphism loci of sequences. After optimizing all parameters, a method of melting-curve analysis following asymmetric PCR was established with dual-fluorescent-reporter in two reaction tubes for each gene. A set of 28 Tm-values was obtained for each strain and then translated into a set of code of allelic genes, standing for the strain's McMLMT type (MT). Meanwhile, sequences of the 7-locus polymorphism were typed according to the method of MLST. To evaluate the efficiency and reliability of McMLMT, the data were compared with that of sequence-typing and PFGE using BioNumerics software.</p><p><b>RESULTS</b>McMLMT method was established and refined for rapid typing of V. cholerae that a dozen of strains can be finished testing in a 3-hours PCR running using 96-well plates. 108 strains were analyzed and 28-Tm-values could be grouped and encoded according to 7 housekeeping gene to obtain the code set of allelic genes, and classified into 18 types (D = 0.723 3). Sequences of the 7 genes' polymorphism areas were directly clustered into the same 18 types with reference to MLST method. 46 of the strains, each represented a different PFGE type, could be classified into 13 types (D = 0.614 5) with McMLMT method and A- K groups at 85% similarity (D = 0.858 9) with PFGE method.</p><p><b>CONCLUSION</b>McMLMT method is a rapid high-throughput molecular typing method for batches of strains with a resolution equal to MLST method and comparable to PFGE group.</p>
Subject(s)
Multilocus Sequence Typing , Polymerase Chain Reaction , Vibrio choleraeABSTRACT
The purpose of the present study was to investigate Norovirus infection status among patients with virus diarrhea in Xiamen city and provide evidence for exploring the prevalence characteristics and constituting appropriate control strategy.From April 2007 to July 2008,323 fecal samples of virus diarrhea cases collected from 3 surveillance hospitals in Xiamen were detected for antigen and RNA by ELISA and Real-Time RT-PCR respectively.The RdPd genes from some samples were furtherly amplified and sequenced for genogroup identification when the Real-Time RT-PCR detection results were positive.In the 323 fecal specimens,68 (21.05%) were positive for Norovirus antigen by ELISA and 107 (31.13%) were positive for Norovirus RNA by Real-Time RT-PCR.The overall positive prevalence rate of Norovirus in Xiamen was 38.08%.107 positive specimens were detected by Real-Time RT-PCR and results showed that 80 strains were Norovirus GGⅡ(74.77%),2 strains were GGⅠ(1.87%) and 25 strains (23.36%)were unidentified.It's indicated that Norovirus infection in Xiamen district was mainly caused by Norovirus GGⅡ,and Norovirus was also the main cause for virus diarrhea.
ABSTRACT
OBJECTIVE:To observe the effects of Yixinkangtai capsule(YXKT) used on old and middle-aged patients before and after operations.METHODS:380 cases were divided into 2 groups:YXKT group(n=190),YXKT was orally given;control group(n=190),placebo was given.In a double blind design,the changes of symptoms,blood viscosity,PaO2,SaO2,NOS and SOD were observed before and after treatment.RESULTS:The symptoms,blood viscosity,PaO2,SaO2,NOS and SOD were significantly improved in YXKT group compared with those in control group.CONCLUSION:YXKT used before and after operation has good clinical effects on old and middle-aged patients.