Seroepidemiology and genotyping of hepatitis E virus in Singapore reveal rise in number of cases and similarity of human strains to those detected in pig livers

Hepatitis E virus (HEV) causes 20 million infections worldwide yearly, of which only about 3.3 million are symptomatic. In developed Asian countries, HEV strains detected in human sera and in food sources were genetically similar, suggesting that indigenous HEV infections may be largely food‐borne. To assess the burden of hepatitis E in Singapore, we performed a seroepidemiologic study of the infection. Additionally, we carried out HEV genotyping on archived, residual HEV IgM‐positive serum samples collected between 2014 and 2016 (n = 449), and on pig liver samples (n = 36) purchased from wet markets and supermarkets. Our study shows a rise in hepatitis E incidence (IgM) from 1.7 to 4.1 cases per 100,000 resident population from 2012 to 2016 and an increase in hepatitis E IgG positivity rate among residents from 14% in 2007 to 35% in 2016. Other findings also suggest the epidemiology of hepatitis E in Singapore has shifted, from it being mainly a disease imported from the Indian subcontinent, to one that is now increasingly prevalent in our resident population. Genotypes obtained from 143 human samples identified the majority to be genotype 3 (n = 121), 21 to be genotype 1 and one to be genotype 4. Further phylogenetic analyses suggest genotype 3a to be the cause of indigenous infections in residents, which showed genetic similarity to the genotype 3a strains detected in pig livers. This link between the strains in the majority of human samples and those in pig livers consumed by the public suggests a possible food‐borne route of HEV infection in Singapore.     

Detection and molecular characterization of calf diarrhoea bovine coronaviruses circulating in South Korea during 2004-2005

Although the widespread occurrence of calf diarrhoea (CD) bovine coronavirus (BCoV) infections have been reported in most cattle producing countries, only the genetic differences in the BCoVs from American and Canadian isolates and/or strains have been identified and compared. Hence, it is unclear if the BCoVs circulating in the other countries have distinct genetic characteristics. The aim of this study was to determine the prevalence and genetic diversity of CD BCoVs based on the deduced amino acid (aa) sequences of the spike (S) and haemagglutinin/esterase (HE) proteins in South Korea. RT-PCR and nested PCR using the primer pairs specific to the nucleocapsid gene, BCoVs detected the BCoVs in 56 (15.6%) of 359 diarrhoeic faecal samples. Phylogenetic analysis of the entire S gene indicated that 10 Korean CD BCoV strains clustered with other Korean BCoV strains with different clinical forms but were different from the American and Canadian BCoV strains. Moreover, the phylogenetic data of the aa sequences of the HE gene revealed all the Korean CD strains to be distinct from the other Korean BCoV strains with different clinical forms. These results suggest that the Korean BCoVs cause endemic infections in diarrhoeic calves in Jeonnam province and have taken a different evolutionary pathway from the BCoVs in other countries. Moreover, the different BCoV strains are circulating in the different clinical forms in South Korea. These results also suggest that vaccines against the BCoVs can be developed with each Korean BCoV in different clinical forms.     

Synthesis of large arrays of well-aligned carbon nanotubes on glass

Free-standing aligned carbon nanotubes have previously been grown above 700 degreesC on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666 degreesC by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas was used as the carbon source and ammonia gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0. 1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication.     

Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.     

An approximately 15,000-year record of El Nino-driven alluviation in southwestern ecuador

Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Nino events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2 to 8.5 years. This is the modern El Nino periodicity, which was established about 5000 calendar years before the present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.     

Enhancing β‐Carotene Content in Asian Noodles by Adding Pumpkin Powder

The influence of ripened pumpkin powder on the characteristics and qualities of noodles was investigated. Varying amounts of pumpkin powder levels (0, 2.5, 5.0, and 10%) were added in making instant fried noodles. These four samples were then evaluated for β‐carotene content, physical dough properties, color, cooking properties, and sensory characteristics. Adding more pumpkin powder increased the level of β‐carotene in the noodles. Amylograph maximum viscosity and temperature and farinograph water absorption and stability decreased as the amount of pumpkin powder increased. Noodles made with more pumpkin powder had a more yellow color than those with less pumpkin powder. Cooked weight and volume were increased by 37 and 59%, respectively, when 5.0% pumpkin powder was added to the flour sample. Gumminess was lowest in the noodles with 5.0% pumpkin powder, while chewiness and hardness were lowest in the noodles with 10.0% pumpkin. Noodles with 5.0% pumpkin powder were the most favorable in appearance, taste, texture, and acceptability among the four samples.     

Occurrence patterns of African manatees,conflicts with humans,and local perception in the Southern Korup Area,Cameroon

相似文献   

Older Chinese and Korean migrants' experiences of the first COVID-19 lockdown in Aotearoa New Zealand: A qualitative study

Later-life migrants, as older people living away from their home nations, occupy multiply-precarious positions in relation to national COVID-19 pandemic responses. Concern has particularly centred on this group's increased risk of social and linguistic exclusion. We explore the perspectives of later-life older Chinese and Koreans living in New Zealand during the nation's COVID-19 lockdown of 2020. This paper presents a sub-analysis of culturally-matched interviews conducted with 3 Korean and 5 Chinese later-life migrants. These participants are a sub-sample of a larger qualitative interview study comprising 44 interviews. A social capital approach has been used to aid conceptualisation of participants' experiences and a reflexive thematic approach guided analysis. Despite their underrepresentation in national response efforts, Chinese and Korean later-life migrants resourcefully participated in ethnically-specific pandemic initiatives. Three themes identified were: (1) taking it seriously (2) already digitally literate (3) challenges and difficulties. Older Asian migrants engaged in a range of creative strategies to stay connected during COVID-19 lockdowns which drew heavily on pre-existing social capital. Future pandemic responses should seek to improve connectedness between the national government COVID-19 response and older Korean and Chinese later-life migrants.     

Low root‐to‐root transmission of a tobamovirus,yellow tailflower mild mottle virus,and resilience of its virions

Tobamoviruses are serious pathogens because they have extremely stable virions, they are transmitted by contact, and they often induce severe disease in crops. Knowledge of the routes of transmission and resilience of tobamovirus virions is essential in understanding the epidemiology of this group of viruses. Here, an isolate of the tobamovirus yellow tailflower mild mottle virus (YTMMV) was used to examine root‐to‐root transmission in soil and in a hydroponic growth environment. Root‐to‐root transmission occurred rarely, and when it occurred plants did not exhibit systemic movement of the virus from the roots to the shoots over a 30‐day period. The resilience of YTMMV virions was tested in dried leaf tissue over time periods from one hour to one year under temperatures ranging from ?80 to 160 °C. Infectivity was maintained for at least a year when incubated at ?80 or 22 °C, or at fluctuating ambient temperatures of 0.8 to 44.4 °C, but incubation under dry conditions at 160 °C for >4 days eliminated infectivity. Exposure of virions to 0.1 m sodium hydroxide or 20% w/v skimmed milk solution for 30 min, treatments recommended for tobamovirus inactivation, did not abolish infectivity of YTMMV.