Experiment on an Integrated Ricefish Polyculture System (6 Species, 1- 2 fish/m2) in the Mekong Delta

Our ricefish polyculture (6 species) results at two stocking densities (1 and 2 fish/m2) show that: The water quality in a ricefish polyculture system, such as water temperature (29.1 – 29.0 °C), water pH (6.6 – 6.7), water transparency (18.0 – 20.8 cm), dissolved O2 (4.7 – 4.6 ppm), CO2 (22.8 – 23.1 ppm), COD (11.9 – 12.7 ppm), are similar at both densities and acceptable for the 6 tropical fish species. Ammonium and phosphorus concentrations are statistically higher at 1 fish/m2 (0.4 and 0.2 ppm). The primary productivity is similar for both densities (6.5 – 6.8 g O2/m3/day) and suitable for fish culture. The phytoplankton biodiversity is relatively high and at the same level for both treatments (74 – 63 taxa), but the densities of phytoplankton, of zooplankton, and the biomass of zoobenthos are lower at the highest density (2 fish/m2), probably due to a higher predation by fish.The fish yield (808 kg/ha) at 2 fish/m2 is higher than at 1 fish/m2 (482 kg/ha). The cost ratio benefit (1.84) and the cost ratio profit (1.81) for farm households at 1 fish/m2 are lower than those values at 2 fish/m2 (2.1 and 2.05 respectively). Regarding the aquaculture extension program, the model of the ricefish polyculture (6 species) system with the stocking density of 2 fish/m2 could be extended in the rice fields to improve farmer's income in the Mekong delta

High magnetisation, monodisperse and water-dispersible CoFe@Pt core/shell nanoparticles

High magnetisation and monodisperse CoFe alloy nanoparticles are desired for a wide range of biomedical applications. However, these CoFe nanoparticles are prone to oxidation, resulting in the deterioration of their magnetic properties. In the current work, CoFe alloy nanoparticles were prepared by thermal decomposition of cobalt and iron carbonyls in organic solvents at high temperatures. Using a seeded growth method, we successfully synthesised chemically stable CoFe@Pt core/shell nanostructures. The obtained core/shell nanoparticles have high saturation magnetisation up to 135 emu g−1. The magnetisation value of the core/shell nanoparticles remains 93 emu g−1 after being exposed to air for 12 weeks. Hydrophobic CoFe@Pt nanoparticles were rendered water-dispersible by encapsulating with poly(maleic anhydride-alt-1-octadecene) (PMAO). These nanoparticles were stable in water for at least 3 months and in a wide range of pH from 2 to 11

A prospective study of hearing changes after beginning zidovudine or didanosine in HIV-1 treatment-naïve people

BACKGROUND: While hearing loss in HIV-infected people after beginning nucleoside reverse transcriptase inhibitors (NRTIs) has been reported, there have been no prospective studies that measured hearing changes longitudinally in treatment-naïve HIV-infected subjects following initiation of regimens containing NRTIs. The goal of this study was to conduct a prospective assessment of the contribution of zidovudine (ZDV) and didanosine (ddI) to hearing loss METHODS/DESIGN: A prospective observational pilot study to determine whether ZDV or ddI, alone or in combination, are associated with sensorineural hearing loss in HIV-infected persons. Changes in hearing levels at all frequencies and in low and high frequency pure tone averages were measured at baseline, 16, and 32 weeks after initiating antiretroviral therapy. DISCUSSION: Treatment with ZDV and ddI did not result in loss of hearing, even after taking into account noise exposure, immune status and age. The results of this prospective pilot study do not support the notion that treatment with nucleoside antiretrovirals damages hearing

Non-Medical Financial Burden in Tuberculosis Care: a Cross-Sectional Survey in Rural China

Background: Treatment of tuberculosis (TB) in China is partially covered by national programs and health insurance schemes, though TB patients often face considerable medical expenditures. For some, especially those from poorer households, non-medical costs, such as transport, accommodation, and nutritional supplementation may be a substantial additional burden. In this article we aim to evaluate these non-medical costs induced by seeking TB care using data from a large scale cross-sectional survey. Methods: A total of 797 TB cases from three cities were randomly selected using a stratified cluster sampling design. Inpatient medical costs, outpatient medical costs, and direct non-medical costs related to TB treatment were collected using in-person interviews by trained interviewers. Mean and median non-medical costs for different sub-groups were calculated and compared using Kruskal-Wallis and Mann–Whitney U tests. Regression analysis was conducted to assess the influence of different patient characteristics on total non-medical cost. Results: The median non-medical cost was RMB 1429, with interquartile range RMB 424–2793. The median non-medical costs relating to inpatient treatment, outpatient treatment, and additional nutrition supplementation were RMB 540, 91, and 900, respectively. Of the 797 cases, 20 % reported catastrophic expenditure on non-medical costs. Statistically significant differences were detected between different cities, age groups, geographical locations, inpatient/outpatient care, education levels and family income groups. Conclusions: Non-medical costs relating to TB treatment are a serious financial burden for many TB patients. Financial assistance that can limit this burden is urgently needed during the treatment period, especially for the poor

Selective Pressure to Increase Charge in Immunodominant Epitopes of the H3 Hemagglutinin Influenza Protein

The evolutionary speed and the consequent immune escape of H3N2 influenza A virus make it an interesting evolutionary system. Charged amino acid residues are often significant contributors to the free energy of binding for protein–protein interactions, including antibody–antigen binding and ligand–receptor binding. We used Markov chain theory and maximum likelihood estimation to model the evolution of the number of charged amino acids on the dominant epitope in the hemagglutinin protein of circulating H3N2 virus strains. The number of charged amino acids increased in the dominant epitope B of the H3N2 virus since introduction in humans in 1968. When epitope A became dominant in 1989, the number of charged amino acids increased in epitope A and decreased in epitope B. Interestingly, the number of charged residues in the dominant epitope of the dominant circulating strain is never fewer than that in the vaccine strain. We propose these results indicate selective pressure for charged amino acids that increase the affinity of the virus epitope for water and decrease the affinity for host antibodies. The standard PAM model of generic protein evolution is unable to capture these trends. The reduced alphabet Markov model (RAMM) model we introduce captures the increased selective pressure for charged amino acids in the dominant epitope of hemagglutinin of H3N2 influenza (R2 > 0.98 between 1968 and 1988). The RAMM model calibrated to historical H3N2 influenza virus evolution in humans fit well to the H3N2/Wyoming virus evolution data from Guinea pig animal model studies

Farm-Level Risk Factors for Fish-Borne Zoonotic Trematode Infection in Integrated Small-Scale Fish Farms in Northern Vietnam

BACKGROUND: Northern Vietnam is an endemic region for fish-borne zoonotic trematodes (FZT), including liver and intestinal flukes. Humans acquire the FZT infection by eating raw or inadequately cooked fish. The production of FZT-free fish in aquaculture is a key component in establishing a sustainable program to prevent and control the FZT transmission to humans. Interventions in aquaculture should be based on knowledge of the main risk factors associated with FZT transmission. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal study was carried out from June 2006 to May 2007 in Nam Dinh province, Red River Delta to investigate the development and risk factors of FZT infections in freshwater cultured fish. A total of 3820 fish were sampled six times at two-month intervals from 96 fish farms. Logistic analysis with repeated measurements was used to evaluate potential risk factors based on information collected through questionnaire interviews with 61 fish farm owners. The results showed that the FZT infections significantly increased from first sampling in June to July 2006 (65%) to sixth sampling in April to May, 2007 (76%). The liver fluke, Clonorchis sinensis and different zoonotic intestinal flukes including Haplochis pumilio, H. taichui, H. yokogawai, Centrocestus formosanus and Procerovum varium were found in sampled fish. Duration of fish cultured (sampling times), mebendazole drug self-medication of household members, presence of snails in the pond, and feeding fish with green vegetation collected outside fish farms all had a significant effect on the development of FZT prevalence in the fish. CONCLUSIONS/SIGNIFICANCE: The FZT prevalence in fish increased by 11 percentage points during a one-year culture period and the risk factors for the development of infection were identified. Results also highlight that the young fish are already highly infected when stocked into the grow-out systems. This knowledge should be incorporated into control programs of FZT transmission in integrated small-scale aquaculture nursery and grow-out systems in Vietnam

Synthesis and Characterization of ZnO Nanorods and Nanodisks from Zinc Chloride Aqueous Solution

ZnO nanorods and nanodisks were synthesized by solution process using zinc chloride as starting material. The morphology of ZnO crystal changed greatly depending on the concentrations of Zn2+ion and ethylene glycohol (EG) additive in the solution. The effect of thermal treatment on the morphology was investigated. Photocatalytic activities of plate-like Zn5(OH)8Cl2 · H2O and rod-like ZnO were characterized. About 18% of 1 ppm NO could be continuously removed by ZnO particles under UV light irradiation