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Objective:To analyze the epidemiological characteristics of novel coronavirus positive cases including confirmed cases with clinical symptoms and asymptomatic infected cases in Guangzhou.Methods:Epidemiological data were collected on the nucleic acid positive cases of COVID-19 in Guangzhou from January to September 2020. The epidemiological characteristics, the distribution of time intervals between the confirmed/isolation date and the date of the first positive detection were analyzed, at last the influencing factors for the confirmed cases and asymptomatic infected persons were discussed.Results:From January 7 to September 4 in 2020, a total of 1 097 nucleic acid positive cases were identified, including 658 confirmed cases (59.98%) and 439 asymptomatic infected cases (40.02%). Among the 658 confirmed cases, the median age was 42 years old, the cases indicated two significant peaks. one of the peaks was related to the imported and associated cases from Hubei province, and the other peak was connected with individuals from overseas. In terms of 439 asymptomatic infected cases, the median age was 32 years old. There were two stages in these cases. The first stage followed the second peak of confirmed cases, and the second stage overlapped with the confirmed cases in Guangzhou when the epidemic was in a period of normal prevention and control, mainly related to imported cases from abroad. The asymptomatic infected persons accounted for 57.32% in all the imported infected cases. In both of asymptomatic and symptomatic cases, the positive rate of pharyngeal swabs was higher than that of nasopharyngeal swabs and anal swabs. There were statistically significant differences in age, source of infection and gender composition between confirmed cases and asymptomatic infected persons ( P<0.05). Older age groups were more likely to have clinical symptoms, with ≥40 years being the risk factor for confirmed cases (OR=2.334, P=0.001), and 20-39 years less likely to have clinical symptoms (OR=0.620, P=0.047), compared with the 0-19 years old group. Compared with those infected in China, those infected abroad were less likely to develop clinical symptoms and became confirmed cases (OR=0.723, P=0.013). Women were more likely to have clinical symptoms than men (OR=1.574, P=0.001). Conclusions:At present, asymptomatic infected persons and confirmed patients with clinical symptoms co-existed, and the number of asymptomatic infected patients was higher than that of confirmed cases in Guangzhou. High age, domestic infection and female may be risk factors for confirmed cases. It was of great value to further explore these underlying mechanisms for the prevention and treatment of the COVID-19.
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In this study ,we established Cross Priming Amplification (CPA ) technology for detection of influenza A virus (H1N1) approach ,and evaluated the method through clinical specimens .A set of specific primers were designed for CPA ac‐cording to the conservative gene sequences ,designed and realized in the same temperature reverse transcription of RNA and DNA amplification . The amplification products can be totally enclosed nucleic acid detection device for testing . Fourteen healthy pharyngeal swab specimens ,seven other respiratory viruses ,and six arboviruses strains were used as the controls .We used a method that application of gradient dilution to the H 1N1 virus strain as the control to test the sensitivity of the CPA .We also used 102 clinical pharyngeal swab specimens of H1N1 patients for detection object to evaluate the feasibility of CPA clinical detection .Results showed that the CPA reaction did not appear cross reaction on health cases samples and other viruses .The sensitivity of the CPA was approximately 10 copies/uL in the established method that exactly titer H1N1 virus strain gradient dilution test .As to the positive results among the clinical pharyngeal swab samples collected from patients at different stages after onset ,the CPA had the highest positive detection rate during the first three days after onset (100% ) .While the detection rate from day 4 to day 6 after onset was 79 .31% .After 7 days ,the detection rate was 9 .09% .The established CPA assay was a highly sensitive ,specific and reproducible approach for rapid detection of H1N1 virus ,which is conducive to the early diagno‐sis of influenza A virus (H1N1) for basic medical units .
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Objective To survey the state of internet addiction of vocational college students and explore the effect of perceived social support and loneliness on Internet addiction.Methods In accordance with random cluster sampling,this research used the Revised Chen Internct Addition Scale,Perceived Social Support scale,and UCLA Loneliness Scale to study lnternet addiction among a total of 1 602 vocational college students from three higher vocational colleges in Guangzhou.Results [nternet addiction rate was 9.87％,and Internet dependence rate was 24.78％.Internet addiction had a higher incidence rate among male students than that among female students (x2=19.775,P＜0.01).The perceived social support group of vocational college students was low,which indicated serious loneliness based on the Loneliness Scale,and their scores on Internet addiction tendency were higher than those of other groups (P＜0.01).The total scores in Internet addiction tendency and perceived social support were negative (r=-0.183,P＜ 0.01),which indicates positive correlation with loneliness (r=0.243,P＜ 0.01).The mediating effect of perceived social support and Internet addiction on loneliness was significant,with a mediation rate of 69.63％.Conclusion Internet addiction tendency of vocational college students is a problem that deserves more attention.Low social support and loneliness can increase the incidence rate of internet addiction tendency.Loneliness is also found to be a strong predictor of internet addiction.
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ObjectiveTo analyze the Envelope (E) gene of type 1,2,3 dengue virus isolated fromGuangzhouin2010, andtoinvestigatetheinfectionsourceandvirusgenotypes.MethodsEighty-five serum samples were collected from 85 patients in acute phase of dengue fever.Dengue virus was cultured and isolated by C6/36 cells.The whole length of E gene was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and then sequenced.The phylogenetic tree was drawn by neighbor-joining method.The bioinformatics analysis was performed by combining the phylogenetic information and the epidemiologic data.ResultsSix strains of type 1 dengue virus,two strains of type 2 dengue virus and six strains of type 3 dengue virus were isolated from 85 samples.The E gene sequence of these strains was obtained by sequencing.The phylogenetic analysis showed that type 1 and 3 dengue virus belonged to two genotypes (Asian and South Pacific ocean,India subcontinent and Southeast Asia/South Pacific ocean,respectively),and type 2 dengue virus belonged to one genotype (Malaysia/India subcontinent).ConclusionIt's presumed that all strains of type 2 dengue virus are imported,four strains of type 1 dengue virus are imported and four strains of type 3 dengue virus arc imported,the remaining two stains of type 1 and two stains of type 3 dengue virus need mosquito intermediary research further to prove their origins.
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Objective To study the high risk factors of anastomotic leakage after colon cancer surgery ,so as to provide evidence for the prevention of anastomotic leakage. Methods Fifty-three patients with anastomotic leakage after colon cancer surgery of 916 cases were selected as research objects,then the correlation between systemic factors,local factors and occurrence of anastomotic leakage was analyzed and studied. Results The correlation between age, ASA grade, serum hemoglobin, red blood cell, total protein, fasting blood glucose of systemic factors except for sex and occurrence of anastomotic leakage was obvious (P< 0.05). There was correlation between the methods of anastomosis, anastomotic tension, setting position of drainage tube, intestinal obstruction, abdominal infection and degree of tumor differentiation except for with or without chemotherapy and radiotherapy and occurrence of anastomotic leakage(P < 0.05). Conclusion The high risk factors of anastomotic leakage after colon cancer surgery are multiple,and well various work should be done during perioperative period.
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Objective To sequence and analyze the envelope (E) gene of type Ⅰ dengue virus isolated from Guangzhou in 2009 for tracing the infection source. Methods The serum samples were collected from patients diagnosed with dengue fever in Guangzhou area during 2009. Dengue virus was isolated and cultured in C6/36 cells.The whole length of E gene was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and then sequenced. The phylogenetic tree was drawn by neighbor-joining method. The bioinformatics analysis was performed by combining the phylogenetic information and the epidemiology data. Results Four strains of type Ⅰ dengue virus were isolated from 19 samples. E gene of these strains was amplified and sequenced. The phylogenetic analysis showed that 09/GZ/9104 strain and 09/GZ/9236 strain had identical nucleotide sequence and fell within the American/African group, 09/GZ/11534 stain and 09/GZ/11562 strain had similar sequence homology and fell within the Asian group. Conclusion The typeⅠdengue viruses in Guangzhou area in 2009 are imported, which belong to two genotypes and may come from two independent origins respectively.
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Objective To evaluate the effect of procedure for prolapse and hemorrhoid(PPH)for the treatment of prolapsed internal hemorrhoids. Methods 23 patients with the third or fourth degree circular prolapsed internal hemorrhoids were managed by means of PPH. Results The mean operative time was 22 minutes,and hospital stay was 3.5 days after operation.Pain in 48 hours after operation was evaluated and 18 cases had no pain(78 3%),5 cases less pain(21 7%).The anastomoses healed in (4～5) weeks and there was no recurrence in (1～6) months after the patients were discharged from hospital. Conslusions Compared with the traditional operation,PPH has the advantages of simpleness,less pain,less complications and quiker recovery,but the cost is higher.