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We report, for the first time, the nonlinear absorption at the 2 µm waveband of three Sb-related materials including two Sb compounds, GaSb and InSb, and one Sb alloy, Ge8Sb92. These saturable absorbers (SAs) were coated on tapered single mode fibers by the magnetron-sputtering deposition method. By incorporating these SAs into Tm-doped fiber lasers, ultrafast mode-locked solitons could be readily obtained. Stable pulse trains with 922 fs/753 fs/1005 fs pulse durations, 31.35 mW/37.70 mW/16.60 mW output powers, 93 dB/80 dB/92 dB signal-to-noise ratios were achieved with GaSb/InSb/Ge8Sb92, respectively. Our findings demonstrate that these materials can be widely used for photonic devices in the 2 µm waveband where ultrafast optical switching and modulating are desired.
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Objective@#To elucidate the epidemiological and etiological features of a local outbreak of dengue fever (DF) in Taijiang district in Fuzhou, Fujian province in 2017, and speculate possible viral source based on phylogenetic analysis.@*Methods@#The clinical and demographic data of cases were collected through field investigation and the outbreak was characterized epidemiologically by descriptive method. The patient′s serum were collected and the adult mosquitoes were captured by anti-mosquito double-net method for the laboratorial test and viral isolation. The viral isolates were typed by real-time fluorescent RT-PCR and their full length of viral envelope (E) genes were amplified by RT-PCR and sequenced. The E gene sequences obtained in this study, together with the reference sequences, were used for the phylogenetic analysis.@*Results@#A total of 13 cases of autochthonous DF were confirmed in the outbreak. All cases presented obvious clinical manifestations and clustered spatially and temporally. The Breteau Index (BI) of mosquito larva density was the highest in epidemic foci of Xingang street and was relatively low in surrounding areas. Four DENV-1 strains, three from patients and one from the captured adult Aedes albopictus, were isolated and identified by real-time RT-PCR. Full length E gene sequences of the four isolates were completely identical and phylogenetic analysis showed that the isolates were genetically closest to the strain (GenBank No. KT825033) from Vietnam in 2014, rather than the DENV-1 strains found in Fujian previously.@*Conclusions@#The DF outbreak occurred in Fuzhou in 2017 was caused by DENV-1 which was imported possibly from somewhere outside of Fujian province and subsequently led to local DF transmission in human via the mosquito Aedes albopictus.
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Objective@#To study the etiological characteristics of an imported Chikungunya fever (CHIK) epidemic in Fujian province in 2018.@*Methods@#Serum samples collected at different days after the onset of the two CHIK cases were detected by real-time RT-PCR and ELISA. Structural protein E1 gene was amplified by RT-PCR and sequenced for nucleotide characteristics analysis and phylogenetic tree analysis.@*Results@#RNA of Chikungunya virus (CHIKV) was detected in the 4 serum samples collected on the first 5 days of the disease, and the earliest IgM antibodies were detected in specimens on the 5th day of the disease, however, IgG antibodies were only detected in specimen on 10th day. Compared with the S27-African prototype strain, 12 mutant points were found in the amino acids of E1 genes in this study. The E1 genes of the two CHIK cases were exactly the same, and they were closest to the evolutionary relationship with the strain isolated in the Philippines in 2014. Their genotype was Asian genotype.@*Conclusions@#This epidemic was confirmed to have been imported from the Philippines after the infection with the Asian genotype CHIKV, which suggests that Fujian province should strengthen the monitoring of persons entering from the CHIK epidemic area, so as to prevent imported cases from causing local outbreaks.
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Objective@#To make laboratorial diagnosis of imported yellow fever (YF) cases in Fujian province with molecular method .@*Methods@#Serum and urine samples were collected from suspected cases at various time-points post illness onset. Real-time RT-PCR and nested RT-PCR were performed respectively for viral specific nucleotide detection and fragment amplification. Sequencing and restrictive fragment length polymorphism (RFLP) method were used to identify the wild virus infection.@*Results@#A total of five cases with wild yellow fever virus (YFV) infection were confirmed in this study. It revealed that the viral agent belonged to Angola-71 like YFV, and the duration of viral agent in urine was longer than that in serum.@*Conclusions@#Simultaneous detection of serum and urine samples would increase detection sensitivity, and further RFLP method contributed to rapid identification of wild YFV infection and exclusion of positive result due to recent vaccination.
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In order to investigate EV71 antibody levels among general population from Fujian Province after the 2008‐2009 HFMD epidemics ,390 sera‐specimens were collected from 390 participants in 2010 .EV71‐specific antibody was detected by neutralization test ,indicating 186 (47 .69% ) sera of 390 were EV71‐seropositive .Although the difference by gender was not statistically significant on positive rates and antibody titers ,significant differences were observed in positive rates and antibody titers among age groups .The positive rate was increasing with age ,while the 0 age‐group yielded the lowest positive rate of 16 .67% .Subsequently ,significant difference was detected among positive rates and antibody titers between age groups of 0 to 4 years‐old and 5‐years‐old ,with the positive rate of 25 .33% and 61 .67% ,respectively .Therefore ,the EV71 antibody levels among general population from Fujian Province after the 2008‐2009 HFMD epidemics was still in the low level ,especially the age groups of 0 to 4 years‐old .The epidemic of HFMD mainly caused by EV71 will still occur in the future ,and children under 5 years old are major susceptible population ,continuously intensive surveillance ,prevention and control are required .
ABSTRACT
Since several dengue viruses (DENV) have been isolated in Fujian Province during the past decade, sequencing and evolution analyses of viral envelope genes are helpful in determining their possible transmission origins. In this study, viral RNA was extracted from 12 DENV strains from Fujian between 20042010. Viral envelope genes were amplified, cloned into TA vectors and sequenced, and the sequence data were subsequently analyzed by bioinformatics software. Full-length E genes of DENV-1 or DENV-2 of 1 485 bp, and DENV- 3 of 1 479 bp were obtained. It was indicated, from BLAST analysis and phylogenetic trees, that DENV strains in Fujian Province during 20042010 shared the highest similarity with Southeast Asian strains, suggesting that DENV circulating in Fujian Province between 20042010 were probably imported from Southeast Asia. Hence, extensive monitoring on passengers from this region at the entry-ports should be strengthened.
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Dengue is the most common vector borne viral disease of humans globally.Detection of viral RNA from suspected patient specimens is rapid,specific and confirmative in laboratory diagnosis of dengue infections during the acute phase.In this study,a multiplex nested reverse transcription PCR (RT-PCR) system was established for clinical specimens.While other nucleic acid amplification tests showed relatively low sensitivity,the multiplex nested RT PCR assay detected 4 cases among blood clots from 8 serologically confirmed dengue patients.These results suggested that blood clots of dengue patients could be used in laboratory diagnosis,and that the multiplex nested RT PCR assay,which simplified the detection procedure,could facilitate viral RNA detection of specimens in clinical laboratories.
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Dengue is the most wide-spread arthropod-borne viral disease of humans in the tropic and sub-tropic regions.In this study,genomic sequences of more than 3 000 dengue viruses available in the GenBank were aligned and analyzed by sero type.According to phylogenetic trees generated by the minimum evolution method of MEGA5.0,dengue viruses were divided into 4-6 genotypes within the four serotypes,respectively.Meanwhile,it was indicated that the distribution of most genotypes was associated with geographic origins of dengue viruses.Probable origins for most of the 39 strains from China with genomic sequences were deduced from relevant ancestral strains in the context of ME trees.These results revealed that the genotype distribution of dengue viruses was geographic origin-specific at genomic level,and that diverse introduction sources were attributed to dengue outbreaks in China.
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Japanese encephalitis virus (JEV) is an important encephalitis virus in Asia, currently both Genotype I (G1) and Genotype III (G3) strains are circulating in China, while JEV isolates from Fujian belonged to G3. In this report, five clinical JEV strains were isolated from specimens of suspected JE patients in Fujian, 2005-2008. Phylogenetic analysis of partial C/PrM and full-length E genes revealed these five strains also belonged to G3. Meanwhile, homogeneity analysis indicated that 2005-2008 isolates were closely related to strains from several years ago, rather than to those strains from 1950s. Minor variations were identified at several amino acid residues of the envelope protein, however, none of these mutations was associated with pathogenicity of JEV. These data contribute to continuous tracking of the geographic evolution of JEV over a long period.
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To solve the problems of induction of anesthesia in patients with extreme trachea occulusion, femoral-femoral cardiopulmonary bypass (FFCPB) was used in 9 patients with nearly total tracheal obstruction prior to induction of anesthesia. After FFCPB was set up under local anesthesia, general anesthesia and surgery began soon. The results showed the patients were quiet and co-operative 3 to 5 mins following FFCPB with the disappearance of tissue hypoxia syndrome and attenuation of hypertension and taehycardia. During FFCPB PaO_2 increased from 7.6～9.8 to 16～40kPa, PaCO_2 decreased from 7.4～8.2 to 4.5～5.9 kPa, SaO_2 increased from 71.6～79.9 to 98.0～99.9%, urine volume, blood pressure and heart rate were maintained at satisfactory levels. The results indicate that FFCPB prior to induction of anesthesia is a rapid, safe and effective method in rescuing patients with nearly complete obstruction of the main trachea.
