199 research outputs found

    Biuret Staining and X-Ray Microanalysis for Locating Grafted Poly(Methyl Acrylate) on Wool Fibers

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    Biuret reagent was used to stain wool fibers with copper so the location of a small amount of poly(methyl acrylate) grafted onto the fibers could be determined by energy dispersive x-ray microanalysis of copper. The grafted polymer was determined to be located in regions of the fibers where cuticle had been previously damaged. The amount of grafted polymer present was too small for secondary electron imaging to be useful for locating the polymer grafts

    Rotavirus.

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    Rotavirus, the most common diarrheal pathogen in children worldwide, causes approximately one third of diarrhea-associated hospitalizations and 800,000 deaths per year. Because natural infection reduces the incidence and severity of subsequent episodes, rotavirus diarrhea might be controlled through vaccination. Serotypespecific immunity may play a role in protection from disease. Tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) (which contains a rhesus rotavirus with serotype G3 specificity and reassortant rhesus-human rotaviruses with G1, G2, and G4 specificity) provides coverage against the four common serotypes of human rotavirus. In clinical trials in industrialized countries, RRV-TV conferred 49% to 68% protection against any rotavirus diarrhea and 61% to 100% protection against severe disease. This vaccine was licensed by the U.S. Food and Drug Administration on August 31, 1998, and should be cost-effective in reducing diarrheal diseases in industrialized countries. The vaccine's efficacy and cost-effectiveness in developing countries should be evaluated

    Epidemiology and strain characterization of rotavirus diarrhea in Malaysia

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    SummaryObjectivesThe objectives of the study were to describe the epidemiology and strain characterization of rotavirus (RV), to determine the proportion of hospitalizations for diarrhea attributable to RV among children under 5 years of age, and to estimate the disease burden of RV diarrhea in Malaysia.MethodsAll children 0–59 months of age admitted for acute gastroenteritis to Kuala Lumpur Hospital (KLH) or Hospital Umum Sarawak (HUS) were surveyed. The periods of surveillance were from February 1, 2001 to April 30, 2003 in KLH and April 1, 2001 to March 31, 2003 for HUS.ResultsThe highest rate of RV-associated diarrhea was among children aged 6–17 months, accounting for 55% of RV-associated diarrhea. There was no seasonality observed in either hospital. P[8]G9 strains were predominant, accounting for 73% of all strains in both hospitals, 80% from KLH and 61% from HUS. There was no mortality.ConclusionsRV was responsible for 38% of hospitalizations for diarrhea. It was most common in the 6–17 months age group. There was no seasonality observed for RV-associated diarrhea. The most prevalent strain of RV was P[8]G9. The estimated incidence of RV-associated diarrhea was 27 per 10000 population under the age of 5 years per year

    CHEMICAL TECHNOLOGY DIVISION, UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT FOR APRIL 1959

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    A concentration cell electrode was installed in a fritted glass surface and was used to measure the surface KCl concentration while water was being transpired through the surface into a mixed tank of 0.1 M KCl. The results from the first Fluorox run made with crude UF/sub 4/ showed that 85.3% of the theoretical amount of UF/sub 6/ was accounted for, with 17.9% being collected in cold traps and the remainder being consumed in various side reactions. Installation was completed of apparatus to study the electrolytic removal of nickel on an engineering scale from concentrated HRT fuel solution. An extremely low yield stress of 0.02 lb/sq ft was measured for a thoria-urania slurry containing 2.5 wt.% Al/sub 2/O/sub 3/ and spherical particles of 1.7 micron mean diameter. Preliminary data on the rate of uranium sorption on Dowex 21K from sulfate solutions were correlated with a simple spherical diffusion model. Laboratory scale studies to determine the effect of reflux time, HNO/sub 3/ concentration, and air sparge on chloride removal from APPR-type Darex dissolver product showed that an air sparge is definitely beneficial in chloride removal. Preliminary cyclic cleaning tests showed that boiling 25% caustic solution was adequate for cleaning type F (20 micron) porous metal filter elements fouled in the absence of filter aid with siliceous sludge from Darex solvent extraction feed solutions. Sections of unirradiated stainless steel-clad UO/sub 2/, sheared into lengths of 1/2 in., 1 in., 2 in., and 2 3/4 in., were leached free of UO/sub 2/ with 10 M HNO/sub 3/ in 30, 45, 60, and 75 min, respectively. The abrasive blade cost for the removal of inert end adapters from selected reactor assemblies ranges from 12 for the Gas-Cooled Reactor to 19 for Consolidated Edison. A zirconium dissolution was carried to completion at 600 ction prod- C in a NaF-LiF salt mixture containing initially 23 mol per cent ZrF/sub 4/ at an average rate of 1.3 mg/(cm/sup 2/)(min) with an HF feed rate of 2 lb/hr. The thermal conductivity and thermal diffusivity at the center of an 8-in. diameter cake of Darex waste calcined at about 900 ction prod- C were determined as a function of temperature. (For preceding period see CF-59-3-61.) (auth

    BASIS WEIGHT UNIFORMITY OF LIGHTLY NEEDLED HYDROENTANGLED COTTON AND COTTON BLEND WEBS

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    New nonwoven products containing cotton and Lyocell (Trademarked name Tencel), low temperature thermal-bondable bicomponent olefin/polyester, or comber noils were developed using needlepunching and spunlacing (hydroentanglement). Webs containing five different blends were prepared by either light needlepunching, or light needlepunching followed by hydroentangling. We acquired detailed basis weight uniformity measurements to learn about processing and the influence of fiber blend composition on web uniformity. Basis weight uniformity was evaluated without regard to web direction ("Total" uniformity), along the machine direction (MD uniformity) and across the cross direction (CD uniformity) at numerous size resolutions. We observed that blending manufactured fibers (either Tencel or olefin/polyester) with bleached cotton and comber noils substantially improved basis weight uniformity of both types of nonwovens. We also observed that subjecting needled webs to hydroentangling significantly improved Total and MD uniformities

    Norovirus Transmission on Cruise Ship

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    We documented transmission by food and person-to-person contact; persistence of virus despite sanitization onboard, including introductions of new strains; and seeding of an outbreak on land

    Chemical Technology Division, Unit Operations Section Monthly Progress Report for June 1959

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    The addition of a surface active agent to an aqueousorganic interface produced a resistance to mass transfer equivalent to slightly more than 1 cm of water. Five semicontinuous Druhm runs were made with 1/2-in. thick MgO liners and terminated due to either failures of the UF/sub 6/ nozzle or a top gasket leak. In preliminary scale-up tests of the flame calcination equipment, a maximum feed rate equivalent to 720 g oxides/hr was achieved using a 3-in. i.d. magnesia reflector with an outside wall temperature of 1500 ction prod- C. In a test with a light water feed, 99% Cu, 25% Ni, and 0% Mn were removed from a UO/ sub 2/SO/sub 4/ solution by electrolysis with a mercury cathode in 7800 ampere hours. The effect of varying the total sulfate concentration on the kinetics of the absorption of uranyl sulfate on Dowex 21K at a uranium concentration of 0.005779 M and a sulfuric acid concentration of 0.020 M was studied in a series of runs using a stirred bath containing enriched uranium. Chloride was removed to 64 ppm in Yankee Atomic and to 70 ppm in APPR solvent extraction feeds using a reference Darex flowsheet with air sparging during a two hour reflux period in the 10-in. prototype titanium feed adjustment tank. Soluble uranium contained in a filter cake deposited onto a 20 micron porous metallic star shaped filter from approximately twenty-one liters of Darex solvent extraction feed solution was recovered to 99.9% by a single 5 liter water wash of the cake. An experimental Redox solvent extraction program was completed. Shear blade evaluation tests have begun at Birdsboro and Clearing under subcontract and will be completed by July 1. Tests were made on the separation of water associated with sheared material through porous bottom baskets as would be required in wet shearing concepts. Consolidated Edison prototype elements assembled with ductile Coast Metals 50 brazing metal could not be disassembled with the impact wedge previously successfully used to disassemble elements made up with brittle Nicrobraze 50. A reactor and condenser system designed to sublime ZrF/sub 4/ from the hydrofluorinator to a separate receiver at temperatures above 902 ction prod- C was operated at condensation rates between 150 and 500 g per hour of ZrF/sub 4/. The thermal conductivities of granular Darex, Purex, and TBP-25 calcined solids were in the range of 0.043 to 0.097 Btu/hr sq ft ( ction prod- F/ft) at room temperature. (For preceding period see CF-59-5-47.) (auth

    CHEMICAL TECHNOLOGY DIVISION, UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT FOR AUGUST 1959

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    The measured diffusivity of uranyl nitrate in water at 25 ction prod- C was 0.7 x 10/sup -6/ cm/sup 2//sec with about 40% average deviation. A program was started to develop nonnuclear uses for depleted uranium. Two continuous DRUHM reaction runs were terminated due to erratic operation of the sodium metering system. In the second Fluorox run with crude UF/sub 4/ which lasted for 29 hr, a total material balance of 94.8% was obtained and 17.9% of the theoretical amount of UF/sub 6/ was collected in cold traps and chemical traps. Room temperature flow rate-pressure drop calibrations of a multiclone (thirteen 0.60-in. diam hydroclones in parallel) for installation with the HRT replacement circulating pump were completed. Mixed oxides of U : Th = 0.08 : 1 and all have low yield stresses of 0.02 to 0.05 lb/sq ft compared to 0.2 to 1.0 lb/sq ft for normal Th-U or Th oxides of 1.5 to 2.5 micron mean diameter. The rates of uranium anion exchange from solutions containing between 0.025 and 0.20 M sulfate were measured and apparent uranium diffusion coefficients between 1.2 x 10/sup -7/ cm/sup 2//sec and 1.6 x 10/sup -7/ cm/sup 2//sec were calculated. In bench scale studies, the Darex reference flowsheet was successfully applied to stainless steel-clad UO/sub 2/ fuels (Yankee Atomic) and to aluminumuranium foreign reactor fuels. The corrosion of titanium A-55 was measured in the vapor and liquid phases of a modified boiling Thorex dissolvent (13 M HNO/sub 3/, 0.04 M F/sup -/, 0.1 M H/sub 3/BO/sub 3/) containing 0.0, 0.5, and 1.0 M thorium from dissolved Consolidated Edison pellets and the maximum corrosion rate was 0.6 mils/ month. Siliceous filter cakes resulting from the filtration of Darex solvent extraction feed solutions through porous metal filter elements were easily washed to a uranium loss of 0.1% in the discarded cake. A run with an acid-deficient Darex-Redox feed containing soluble silica resulted in uranium losses higher by a factor of 20 than those previously obtained in the same column with a standard Redox feed. Batch leaching of sheared pieces, 1/2 in. to 5 in. long, of PWR reject UO/sub 2/ pellets clad with stainless steel, 0.40 in. o.d. with 0.10 in. wall, in boiling 10 M HNO/sub 3/ (173% excess) was completed in 70 to 245 min. Dissolution test runs of Zr-2 in fused salt made at approximately 700 ction prod- C under identical conditions except for HF feed rate resulted in dissolution rates of 1.87 and 2.68 mg/min-sq cm for 2.5 and 6.0 lb/hr HF feed rate, respectively. Purex and TBP-25 evaporated wastes were calcined at 900 to 1000 ction prod- C resulting in solid wastes which had densities of 0.77 to 0.83 and 0.40 to 0.45 g/cc, respectively. (For preceding period see CF-59-4-47.) (auth

    Potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study

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    BACKGROUND: Influenza is a major year-round cause of respiratory illness in Kenya, particularly in children under 5. Current influenza vaccines result in short-term, strain-specific immunity and were found in a previous study not to be cost-effective in Kenya. However, next-generation vaccines are in development that may have a greater impact and cost-effectiveness profile. METHODS: We expanded a model previously used to evaluate the cost-effectiveness of seasonal influenza vaccines in Kenya to include next-generation vaccines by allowing for enhanced vaccine characteristics and multi-annual immunity. We specifically examined vaccinating children under 5 years of age with improved vaccines, evaluating vaccines with combinations of increased vaccine effectiveness, cross-protection between strains (breadth) and duration of immunity. We evaluated cost-effectiveness using incremental cost-effectiveness ratios (ICERs) and incremental net monetary benefits (INMBs) for a range of values for the willingness-to-pay (WTP) per DALY averted. Finally, we estimated threshold per-dose vaccine prices at which vaccination becomes cost-effective. RESULTS: Next-generation vaccines can be cost-effective, dependent on the vaccine characteristics and assumed WTP thresholds. Universal vaccines (assumed to provide long-term and broad immunity) are most cost-effective in Kenya across three of four WTP thresholds evaluated, with the lowest median value of ICER per DALY averted (263,95263, 95% Credible Interval (CrI):  - 1698, 1061)andthehighestmedianINMBs.AtaWTPof1061) and the highest median INMBs. At a WTP of 623, universal vaccines are cost-effective at or below a median price of 5.16perdose(955.16 per dose (95% CrI: 0.94, $18.57). We also show that the assumed mechanism underlying infection-derived immunity strongly impacts vaccine outcomes. CONCLUSIONS: This evaluation provides evidence for country-level decision makers about future next-generation vaccine introduction, as well as global research funders about the potential market for these vaccines. Next-generation vaccines may offer a cost-effective intervention to reduce influenza burden in low-income countries with year-round seasonality like Kenya

    Data and product needs for influenza immunization programs in low- and middle-income countries: Rationale and main conclusions of the WHO preferred product characteristics for next-generation influenza vaccines.

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    In 2017, WHO convened a working group of global experts to develop the Preferred Product Characteristics (PPC) for Next-Generation Influenza Vaccines. PPCs are intended to encourage innovation in vaccine development. They describe WHO preferences for parameters of vaccines, in particular their indications, target groups, implementation strategies, and clinical data needed for assessment of safety and efficacy. PPCs are shaped by the global unmet public health need in a priority disease area for which WHO encourages vaccine development. These preferences reflect WHO's mandate to promote the development of vaccines with high public health impact and suitability in Low- and Middle-Income Countries (LMIC). The target audience is all entities intending to develop or to achieve widespread adoption of a specific influenza vaccine product in these settings. The working group determined that existing influenza vaccines are not well suited for LMIC use. While many developed country manufactures and research funders prioritize influenza vaccine products for use in adults and the elderly, most LMICs do not have sufficiently strong health systems to deliver vaccines to these groups. Policy makers from LMICs are expected to place higher value on vaccines indicated for prevention of severe illness, however the clinical development of influenza vaccines focuses on demonstrating prevention of any influenza illness. Many influenza vaccine products do not meet WHO standards for programmatic suitability of vaccines, which introduces challenges when vaccines are used in low-resource settings. And finally, current vaccines do not integrate well with routine immunization programs in LMICs, given age of vaccine licensure, arbitrary expiration dates timed for temperate country markets, and the need for year-round immunization in countries with prolonged influenza seasonality. While all interested parties should refer to the full PPC document for details, in this article we highlight data needs for new influenza vaccines to better demonstrate the value proposition in LMICs
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