779 research outputs found

    On the Maxwell-Stefan approach to multicomponent diffusion

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    We consider the system of Maxwell-Stefan equations which describe multicomponent diffusive fluxes in non-dilute solutions or gas mixtures. We apply the Perron-Frobenius theorem to the irreducible and quasi-positive matrix which governs the flux-force relations and are able to show normal ellipticity of the associated multicomponent diffusion operator. This provides local-in-time wellposedness of the Maxwell-Stefan multicomponent diffusion system in the isobaric, isothermal case.Comment: Based on a talk given at the Conference on Nonlinear Parabolic Problems in Bedlewo, Mai 200

    Effect of Fe:ligand ratios on hydroponic conditions and calcareous soil in Solanum lycopersicum L. and Glycine max L. fertilized with heptagluconate and gluconate

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    BACKGROUND: The environmental risk from the application of synthetic chelates has led to the use of biodegradable complexes to correct Fe deficiency in plants. In this article, the Fe oxidation state, the Fe:ligand ratio, and the molecular weight distribution for heptagluconate (G7) and gluconate (G6) are considered as key factors for the efficacy of complexes as fertilizers. Complexes with different Fe:ligand ratios were prepared and analyzed by gel filtration chromatography (GFC). The ability of Fe:ligand ratios to provide Fe to tomato in hydroponics and soybean in calcareous soil was tested and compared with synthetic chelates (Fe3+:HBED and Fe3+:EDTA). RESULTS: G7 presented greater capacity to complex both Fe(II) and Fe(III) than G6, but the Fe(II) complexes exhibited poor stability at pH 9 and oxidation in solution. Gel filtration chromatography demonstrated the polynuclear nature of the Fe3+:G7 at various ratios. The effectiveness of the Fe fertilizers depend on the Fe3+:ligand ratio and the ligand type, the Fe3+:G7 (1:1 and 1:2) being the most effective. Fe3+:G7 (1:1) also presented a better response for the uptake of other micronutrients. CONCLUSION: Fe3+:G7 molar ratios have been shown to be critical for plant Fe uptake under hydroponic conditions and with calcareous soil. Thus, the Fe3+:G7 at equimolar ratio and 1:2 molar ratio can be an environmentally friendly alternative to less degradable synthetic chelates to correct Fe chlorosis in strategy I plantsThis work was supported by the State Research Agency, Ministry of Science, Innovation and Universities of Spain (projects AGL2013-44474-R and RTI2018-096268-B-I00) and the Comunidad de Madrid (Spain) and Structural Funds 2014-2020 (ERDF and ESF) (project AGRISOST-CM S2018/BAA-4330). SIV would like to thank the Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico) for supporting her grant through PhD studentship number 278934, and the Consejo de Ciencia, Tecnología e Innovación de Hidalgo (CITNOVA, Mexico

    Mosquito Abundance, Bed net Coverage and Other Factors Associated with Variations in Sporozoite Infectivity Rates in Four Villages of Rural Tanzania.

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    Entomological surveys are of great importance in decision-making processes regarding malaria control strategies because they help to identify associations between vector abundance both species-specific ecology and disease intervention factors associated with malaria transmission. Sporozoite infectivity rates, mosquito host blood meal source, bed net coverage and mosquito abundance were assessed in this study. A longitudinal survey was conducted in four villages in two regions of Tanzania. Malaria vectors were sampled using the CDC light trap and pyrethrum spray catch methods. In each village, ten paired houses were selected for mosquitoes sampling. Sampling was done in fortnight case and study was undertaken for six months in both Kilimanjaro (Northern Tanzania) and Dodoma (Central Tanzania) regions. A total of 6,883 mosquitoes were collected including: 5,628 (81.8%) Anopheles arabiensis, 1,100 (15.9%) Culex quinquefasciatus, 89 (1.4%) Anopheles funestus, and 66 (0.9%) Anopheles gambiae s.s. Of the total mosquitoes collected 3,861 were captured by CDC light trap and 3,022 by the pyrethrum spray catch method. The overall light trap: spray catch ratio was 1.3:1. Mosquito densities per room were 96.5 and 75.5 for light trap and pyrethrum spray catch respectively. Mosquito infectivity rates between villages that have high proportion of bed net owners and those without bed nets was significant (P < 0.001) and there was a significant difference in sporozoite rates between households with and without bed nets in these four villages (P < 0.001). Malaria remains a major problem in the study areas characterized as low transmission sites. Further studies are required to establish the annual entomological inoculation rates and to observe the annual parasitaemia dynamics in these communities. Outdoor mosquitoes collection should also be considered

    An invisibility cloak using silver nanowires

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    In this paper, we use the parameter retrieval method together with an analytical effective medium approach to design a well-performed invisible cloak, which is based on an empirical revised version of the reduced cloak. The designed cloak can be implemented by silver nanowires with elliptical cross-sections embedded in a polymethyl methacrylate host. This cloak is numerically proved to be robust for both the inner hidden object as well as incoming detecting waves, and is much simpler thus easier to manufacture when compared with the earlier proposed one [Nat. Photon. 1, 224 (2007)].Comment: 7 pages, 4 figures, 2 table

    Clinical-pathological study on β-APP, IL-1β, GFAP, NFL, Spectrin II, 8OHdG, TUNEL, miR-21, miR-16, miR-92 expressions to verify DAI-diagnosis, grade and prognosis

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    Traumatic brain injury (TBI) is one of the most important death and disability cause, involving substantial costs, also in economic terms, when considering the young age of the involved subject. Aim of this paper is to report a series of patients treated at our institutions, to verify neurological results at six months or survival; in fatal cases we searched for βAPP, GFAP, IL-1β, NFL, Spectrin II, TUNEL and miR-21, miR-16, and miR-92 expressions in brain samples, to verify DAI diagnosis and grade as strong predictor of survival and inflammatory response. Concentrations of 8OHdG as measurement of oxidative stress was performed. Immunoreaction of β-APP, IL-1β, GFAP, NFL, Spectrin II and 8OHdG were significantly increased in the TBI group with respect to control group subjects. Cell apoptosis, measured by TUNEL assay, were significantly higher in the study group than control cases. Results indicated that miR-21, miR-92 and miR-16 have a high predictive power in discriminating trauma brain cases from controls and could represent promising biomarkers as strong predictor of survival, and for the diagnosis of postmortem traumatic brain injury

    Conducting Health Research in Korean American Churches: Perspectives from Church Leaders

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    Korean Americans experience many challenges to obtaining adequate health care coverage and access to needed services. Because a large proportion of Korean Americans attend churches on a regular basis, churches may be a promising venue where health programs can be delivered. In order to gain an in-depth understanding of Korean American churches with respect to conducting future health intervention research, we conducted exploratory interviews and focus groups with 58 leaders from 23 Korean American churches and three community organizations. From these interviews and focus groups, we found that Korean churches and church leaders seek to meet a variety of social and health needs of their congregation and their surrounding community. Several leaders have stated that assisting with social and medical needs of their members is an important component of their current ministry. They described profound health needs of their congregations and have suggested various ways in which the university can partner with the local churches to help address these needs through research. Additionally, they described various resources churches can provide to researchers such as: their personal assistance, church volunteer base, church facility, and church network and contacts. Our findings suggest that Korean churches have a high potential to serve an important role in the health of Korean Americans. On the basis of the promising results of the present study, we are planning to conduct a cross sectional survey of Korean church leaders and members in Los Angeles County to substantiate our findings in a larger representative sample

    Protective Efficacy of Menthol Propylene Glycol Carbonate Compared to N, N-diethyl-Methylbenzamide Against Mosquito Bites in Northern Tanzania.

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    The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08), Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET), either as a single dose or in combination (blend), both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus. In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00  hr to 01:00  hr. A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30%) were An. gambiae s.l while 66 (2.70%) were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx. quinquefasciatus were significantly prevented from blood feeding compared to An. gambiae s.l. The incorporation of these topical repellents for protection against insect bites can be of additional value in the absence or presence of IRS and ITNs coverage. However, a combination of both the physical (bed nets) and the repellent should be used in an integrated manner for maximum protection, especially before going to bed. Additional research is needed to develop repellents with longer duration of protection

    Gene array of VHL mutation and hypoxia shows novel hypoxia-induced genes and that cyclin D1 is a VHL target gene

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    Gene expression analysis was performed on a human renal cancer cell line (786-0) with mutated VHL gene and a transfectant with wild-type VHL to analyse genes regulated by VHL and to compare with the gene programme regulated by hypoxia. There was a highly significant concordance of the global gene response to hypoxia and genes suppressed by VHL. Cyclin D1 was the most highly inducible transcript and 14-3-3 epsilon was downregulated. There were some genes regulated by VHL but not hypoxia in the renal cell line, suggesting a VHL role independent of hypoxia. However in nonrenal cell lines they were hypoxia regulated. These included several new pathways regulated by hypoxia, including RNase 6PL, collagen type 1 alpha 1, integrin alpha 5, ferritin light polypeptide, JM4 protein, transgelin and L1 cell adhesion molecule. These were not found in a recent SAGE analysis of the same cell line. Hypoxia induced downregulation of Cyclin D1 in nonrenal cells via an HIF independent pathway. The selective regulation of Cyclin D1 by hypoxia in renal cells may therefore contribute to the tissue selectivity of VHL mutation
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