13 research outputs found
Micro-CT screening of old shell collections helps to understand the distribution of viviparity in the highly diversifed clausiliid clade of land snails
Current zoological research may benefit in many ways from the study of old collections of shells. These collections may provide materials for the verification of broad zoogeographical and ecological hypotheses on the reproduction of molluscs, as they include records from many areas where sampling is currently impossible or very difficult due to political circumstances. In the present paper we present data on viviparous and embryo-retention reproductive modes in clausiliid land snails (subfamily Phaedusinae) acquired from specimens collected since the nineteenth century in the Pontic, Hyrcanian, and East and Southeast Asian regions. X-ray imaging (micro-CT) enabled relatively quick screening of more than 1,000 individuals classified within 141 taxa, among which we discovered 205 shells containing embryos or eggs. Gravid individuals were found to belong to 55 species, representing, for some of these species, the first indication of brooding reproductive strategy
8He nuclei stopped in nuclear track emulsion
The ACCULINNA fragment separator in the G. N. Flerov Laboratory of Nuclear Reactions was used to irradiate a nuclear track emulsion by a beam of radioactive 8He nuclei of energy of 60 MeV and enrichment of about 80%. Measurements of 278 decays of 8He nuclei stopped in the emulsion allow one to evaluate possibilities of α-spectrometry and to observe a thermal drift of 8He
He nuclei stopped in nuclear track emulsion
The ACCULINNA fragment separator in the G. N. Flerov Laboratory of Nuclear Reactions was used to irradiate a nuclear track emulsion by a beam of radioactive 8He nuclei of energy of 60 MeV and enrichment of about 80%. Measurements of 278 decays of 8He nuclei stopped in the emulsion allow one to evaluate possibilities of α-spectrometry and to observe a thermal drift of 8He
The reproductive strategies of clausiliid land snails from Northern Vietnam (Gastropoda: Stylommatophora)
Global prevalence, treatment, and prevention of hepatitis B virus infection in 2016: a modelling study.
Background The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate viral hepatitis
by 2030. Although no virological cure exists for hepatitis B virus (HBV) infection, existing therapies to control viral
replication and prophylaxis to minimise mother-to-child transmission make elimination of HBV feasible. We aimed
to estimate the national, regional, and global prevalence of HBsAg in the general population and in the population
aged 5 years in 2016, as well as coverage of prophylaxis, diagnosis, and treatment.
Methods In this modelling study, we used a Delphi process that included a literature review in PubMed and Embase,
followed by interviews with experts, to quantify the historical epidemiology of HBV infection. We then used a dynamic
HBV transmission and progression model to estimate the country-level and regional-level prevalence of HBsAg
in 2016 and the effect of prophylaxis and treatment on disease burden.
Findings We developed models for 120 countries, 78 of which were populated with data approved by experts. Using these
models, we estimated that the global prevalence of HBsAg in 2016 was 3\ub79% (95% uncertainty interval [UI] 3\ub74\u20134\ub76),
corresponding to 291992000 (251513000\u2013341114 000) infections. Of these infections, around 29 million (10%) were
diagnosed, and only 4\ub78 million (5%) of 94 million individuals eligible for treatment actually received antiviral therapy.
Around 1\ub78 (1\ub76\u20132\ub72) million infections were in children aged 5 years, with a prevalence of 1\ub74% (1\ub72\u20131\ub76). We estimated
that 87% of infants had received the three-dose HBV vaccination in the first year of life, 46% had received timely birthdose vaccination, and 13% had received hepatitis B immunoglobulin along with the full vaccination regimen. Less than
1% of mothers with a high viral load had received antiviral therapy to reduce mother-to-child transmission.
Interpretation Our estimate of HBV prevalence in 2016 differs from previous studies, potentially because we took into
account the effect of infant prophylaxis and early childhood vaccination, as well as changing prevalence over time.
Although some regions are well on their way to meeting prophylaxis and prevalence targets, all regions must
substantially scale-up access to diagnosis and treatment to meet the global targets
Global prevalence, treatment, and prevention of hepatitis B virus infection in 2016: a modelling study
BACKGROUND: The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate viral hepatitis by 2030. Although no virological cure exists for hepatitis B virus (HBV) infection, existing therapies to control viral replication and prophylaxis to minimise mother-to-child transmission make elimination of HBV feasible. We aimed to estimate the national, regional, and global prevalence of HBsAg in the general population and in the population aged 5 years in 2016, as well as coverage of prophylaxis, diagnosis, and treatment. METHODS: In this modelling study, we used a Delphi process that included a literature review in PubMed and Embase, followed by interviews with experts, to quantify the historical epidemiology of HBV infection. We then used a dynamic HBV transmission and progression model to estimate the country-level and regional-level prevalence of HBsAg in 2016 and the effect of prophylaxis and treatment on disease burden. FINDINGS: We developed models for 120 countries, 78 of which were populated with data approved by experts. Using these models, we estimated that the global prevalence of HBsAg in 2016 was 3·9% (95% uncertainty interval [UI] 3·4-4·6), corresponding to 291 992 000 (251 513 000-341 114 000) infections. Of these infections, around 29 million (10%) were diagnosed, and only 4·8 million (5%) of 94 million individuals eligible for treatment actually received antiviral therapy. Around 1·8 (1·6-2·2) million infections were in children aged 5 years, with a prevalence of 1·4% (1·2-1·6). We estimated that 87% of infants had received the three-dose HBV vaccination in the first year of life, 46% had received timely birth-dose vaccination, and 13% had received hepatitis B immunoglobulin along with the full vaccination regimen. Less than 1% of mothers with a high viral load had received antiviral therapy to reduce mother-to-child transmission. INTERPRETATION: Our estimate of HBV prevalence in 2016 differs from previous studies, potentially because we took into account the effect of infant prophylaxis and early childhood vaccination, as well as changing prevalence over time. Although some regions are well on their way to meeting prophylaxis and prevalence targets, all regions must substantially scale-up access to diagnosis and treatment to meet the global targets. FUNDING: John C Martin Foundation.status: publishe