A liquid metal dropper for experiments on the wettability of liquid metals on plasma facing components.

A liquid metal dropper has been developed as a part of the Ion-Gas-Neutral Interactions with Surfaces 2 (IGNIS-2) facility at The Pennsylvania State University. The dropper has the capability of directly applying drops to candidate plasma facing materials for nuclear fusion reactors to enable measurements of their liquid metal wetting properties. The results presented here are specific to the use of lithium in the dropper. This paper discusses the design choices of the liquid metal dropper and its chamber, including the heating and temperature control and the dropper's motorized operation. Lithium drops of masses ranging from 0.05 g up to 0.13 g, equivalent to drop diameters between 5.6 mm to 1 cm, have been consistently dispensed by the dropper. A new algorithm is developed and used to automate the analysis of the contact angle between the liquid drops and substrate material for efficient analysis of video data recorded to study the wetting properties of candidate plasma-facing components.

Development of the materials analysis and particle probe for Proto-MPEX.

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being used in plasma source research and development (R&D) for the proposed MPEX. Once the R&D is completed, this device can also be used to perform plasma-material interaction studies. To perform these studies, a new materials analysis and particle probe (MAPP) has been constructed. The MAPP's components are a sample holder and manipulator and a custom vacuum chamber with ports to facilitate surface chemistry diagnostics. The MAPP's overall design enables rapid sample turnaround and in vacuo surface characterization. The surface analysis vacuum chamber has ports for x-ray photoelectron spectroscopy, thermal desorption spectroscopy, back-scatter ion scattering spectroscopy, forward-scatter ion scattering spectroscopy, and direct recoil spectroscopy. The sample manipulator and holder is a Lesker/UHV Multi-Centre Analytical Stage, which is used to place the samples in the exposure region of the Proto-MPEX or the analysis position in the MAPP vacuum chamber. The sample holder has a heating capability of up to 1200 °C for heated exposure and for desorption studies. In this work, we present the MAPP's design and the first tungsten sample exposure with ex situ analysis that shows a surface deposition layer on the exposed target, highlighting the need for additional in situ measurements on the Proto-MPEX.

Publisher Correction: Effect of deuterium irradiation on graphite boronized in the NSTX-U tokamak.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Current approaches to increase blood donations in resource-limited countries.

BACKGROUND: Low- and middle-income countries (LMIC) suffer from chronic or seasonal blood shortage. The first review was published in 2007. METHODS: The review of literature since 2005 presented here uncovered a fairly large number of articles justifying the grouping of blood donation issues into five geographical areas sharing common background. These are Sub-Saharan Africa (SSA), Muslim countries, India, China/South East Asia and Latin America/Caribbean islands (LA&C). RESULTS: SSA countries start collecting at 16-18 years of age in schools where female donors can be reached better than in other settings. Community-oriented culture favours family donors who need, similar to volunteer non-remunerated donors (VNRD), to be actively induced to repeat donation. Muslim countries share the contradiction of religion encouraging blood donation but restrain women from donating. The active involvement of religious leaders and the progressive easing of female participation are the keys to increasing blood donation. In India, 'social duty' is a major inducement to blood donation but also benefits and rewards. Ways of involving female donors by reducing the donation age to 16 years and providing donor education in schools need to be considered. In China and East Asia, the option of small-volume donation impairs blood collection without being justified by scientific evidence but is a concession to culture. Reducing the donation age would also help the supply. In LA&C, the concept of 'social capital' was developed as a complement or alternative to the theory of planned behaviour. CONCLUSIONS: Strategies to improve blood donation and repeat donation should be innovative and adapted to local or regional culture and environment.

Effect of deuterium irradiation on graphite boronized in the NSTX-U tokamak.

Boronization has been used in the National Spherical Torus-Upgrade (NSTX-U) as first wall conditioning technique. The technique decreased the oxygen impurities in the plasma and the O% on the Plasma Facing Components (PFC) as measured with an in-vacuo probe. Samples were extracted from tiles removed from the tokamak for post-mortem and controlled studies. Ex-vessel low energy and fluence D2+ and Ar+ irradiations were characterized in-situ to elucidate surface evolution of a cored graphite sample with an intrinsic concentration of boron from a tokamak environment. In addition, quadrupole mass spectrometer measurements of emitted D-containing species during irradiation, indicate potential retention of D by the boronized graphite interface and correlated back to the surface chemistry evolution. Classical Molecular Dynamics (CMD) simulations were used to investigate the chemistry of the B-C-O-D system. The results suggest that boron coatings retain oxygen by forming oxidized boron states in the presence of deuterium plasmas and corroborate empirical findings. A four times increase in the O% of the boron coatings was observed following in-situ deuterium exposures, in contrast with a reduction of equal magnitude observed after Ar irradiations. These results illustrate the complex chemistry driven by energetic ions at the edge of tokamaks plasmas on the PFCs.

Incidence of hepatitis B virus infection in young Chinese blood donors born after mandatory implementation of neonatal hepatitis B vaccination nationwide.

This study was carried out to determine the incidence of hepatitis B virus (HBV) infection in the young generation born after mandatory implementation of hepatitis B vaccination since 1992. Repeat blood donors born between 1992 and 1997 were enrolled, who gave blood at least twice during the past 3 years. Donors were tested for HBV infection markers of HBsAg, anti-HBc, anti-HBs and viral DNA by immunoassays (EIAs) and nucleic acid tests (NAT). A total of 14 937 pre-donation screening qualified young repeat donors aged 18-23 years were tested with 9 (0.06%) being HBsAg by EIA and 10 (1:1494) HBV DNA positive by Ultrio NAT (10.4 IU/mL), respectively. HBV DNA was further detected in 1:192 (9/1732) anti-HBc+ repeat donors with Ultrio Plus NAT (3.4 IU/mL). Most cases were identified as occult HBV infection (OBI). Of 14 937 repeat donors, 20.9% were anti-HBc+ positive, while approximately 50% of 12 024 repeat donors were anti-HBs negative or had levels <100 IU/L. HBsAg+ or OBI strains were classified as wild type of genotype B or genotype C. Incident HBV infection in repeat donors was approximately 1:18.5 person-years (1.1%/year) but significantly less frequent in donors with confirmed HBV vaccination (2.4%-3.3%) than those unsure of vaccination status (10.5%; P = .0023). Hepatitis B virus vaccination appears largely protective of HBV infection, but incidence of infections increases in young adults with mostly undetectable or low anti-HBs or occasionally high anti-HBs. A boost of hepatitis B vaccine for adolescents prior to age 18 years may reduce HBV infection, and implementation of more sensitive NAT in blood donation screening may improve HBV safety in blood transfusion.

Pathogen reduction of whole blood: utility and feasibility.

OBJECTIVES: To collect information on pathogen reduction applied to whole blood. BACKGROUND: Pathogen reduction (PR) of blood components has been developed over the past two decades, and pathogen-reduced fresh-frozen plasma and platelet concentrates are currently in clinical use. High cost and incomplete coverage of components make PR out of reach for low- and middle-income countries (LMIC). However, should PR become applicable to whole blood (WB), the main product transfused in sub-Saharan Africa, and be compatible with the preparation of clinically suitable components, cost would be minimised, and a range of safety measures in place at high cost in developed areas would become redundant. METHODS: All articles called with "pathogen reduction", "pathogen inactivation" and "whole blood" were retrieved from Medline. References in articles were utilised. RESULTS: One such PR technology (PRT) applied to WB has been developed and has shown efficacious against viruses, bacteria and parasites in vitro; and has been able to inactivate nucleated blood cells whilst retaining the ability to prepare components with acceptable characteristics. The efficacy of this WB PRT has been demonstrated in vivo using the inactivation of Plasmodium falciparum as a model and showing a high degree of correlation between in vitro and in vivo data. Obtaining further evidence of efficacy on other suitable targets is warranted. Shortening of the process, which is currently around 50 min, or increasing the number of units simultaneously processed would be necessary to make PRT WB conducive to LMIC blood services' needs. CONCLUSIONS: Even if not 100% effective against agents that are present in high pathogen load titres, WB PRT could massively impact blood safety in LMIC by providing safer products at an affordable cost.

Unraveling wall conditioning effects on plasma facing components in NSTX-U with the Materials Analysis Particle Probe (MAPP).

A novel Plasma Facing Components (PFCs) diagnostic, the Materials Analysis Particle Probe (MAPP), has been recently commissioned in the National Spherical Torus Experiment Upgrade (NSTX-U). MAPP is currently monitoring the chemical evolution of the PFCs in the NSTX-U lower divertor at 107 cm from the tokamak axis on a day-to-day basis. In this work, we summarize the methodology that was adopted to obtain qualitative and quantitative descriptions of the samples chemistry. Using this methodology, we were able to describe all the features in all our spectra to within a standard deviation of ±0.22 eV in position and ±248 s-1 eV in area. Additionally, we provide an example of this methodology with data of boronized ATJ graphite exposed to NSTX-U plasmas.

Ion beam nanopatterning of III-V semiconductors: consistency of experimental and simulation trends within a chemistry-driven theory.

Several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.

Development progress of the Materials Analysis and Particle Probe.

The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

Characterization of major histocompatibility complex class I allele polymorphisms in common marmosets.

Currently, little information is available for major histocompatibility complex (MHC)-I that conditions the T-cell response of marmosets. In this study, 471 clones of MHC-I cDNA sequences were isolated from 12 marmosets. Twenty full-length sequences of class I G (Caja-G) alleles were obtained from these marmosets, 15 of them were novel. Among these 20 Caja-G alleles, 10 were found in individual animals while the rests were in two to four marmosets, but none was common to all animals. Ten marmosets possessed one to three Caja-G alleles, and two marmosets carried five or six alleles, which suggested that the Caja-G locus was duplicated in marmoset's genome. The high polymorphisms of Caja-G sequences provided important information helpful for understanding the cellular immune response in virus-infected marmosets.

In-situ TEM observation of the response of ultrafine- and nanocrystalline-grained tungsten to extreme irradiation environments.

The accumulation of defects, and in particular He bubbles, can have significant implications for the performance of materials exposed to the plasma in magnetic-confinement nuclear fusion reactors. Some of the most promising candidates for deployment into such environments are nanocrystalline materials as the engineering of grain boundary density offers the possibility of tailoring their radiation resistance properties. In order to investigate the microstructural evolution of ultrafine- and nanocrystalline-grained tungsten under conditions similar to those in a reactor, a transmission electron microscopy study with in situ 2 keV He(+) ion irradiation at 950 °C has been completed. A dynamic and complex evolution in the microstructure was observed including the formation of defect clusters, dislocations and bubbles. Nanocrystalline grains with dimensions less than around 60 nm demonstrated lower bubble density and greater bubble size than larger nanocrystalline (60-100 nm) and ultrafine (100-500 nm) grains. In grains over 100 nm, uniform distributions of bubbles and defects were formed. At higher fluences, large faceted bubbles were observed on the grain boundaries, especially on those of nanocrystalline grains, indicating the important role grain boundaries can play in trapping He and thus in giving rise to the enhanced radiation tolerance of nanocrystalline materials.

Appropriateness of blood product transfusion in the Obstetrics and Gynaecology (O&G) department of a tertiary hospital in West Africa.

BACKGROUND: Misuse of blood by clinicians was suggested to explain blood shortage in sub-Saharan Africa although based on little evidence. This study evaluated whether routine halving (restricted) of blood requests was justified. STUDY DESIGN AND METHODS: On alternated days for 3 months in 2011-2012, restricted or full blood product supply [whole blood (WB), red cell concentrate (RCC)] was provided to the Obstetrics & Gynaecology department (O&G). Patient age, haemoglobin (Hb) level pre- and post-transfusion, clinical condition, blood products request and supply, transfused and returned, clinical outcome were collated. RESULTS: Five hundred and nineteen patients (249 restricted and 270 full supply) received 1001 blood products (94.6% WB, 6.4% RCC). Clinical conditions were severe peri-partum bleeding (72.4%) requiring emergency transfusion (82%) whilst 27.6% of total transfusion was for anaemia, 18% being moderate (8-10 g dL(-1) ). Pre-transfusion Hb level was <6 g dL(-1) in 36.7%, 6-8 g dL(-1) 29.1% and ≥ 8 g dL(-1) in 33.2% of cases. Fifty-five percent of the transfused blood was stored ≤ 1 week. Restricted supply triggered additional request (40%) compared to 10% in full supply mode. Whether with restricted or full supply, blood requests, supply and units transfused/patient were similar (restricted 2.3 and 2.1 unit patient(-1) and full 2.9 and 2.3 unit patient(-1) , respectively). Fatal clinical outcome was 3.1% evenly distributed between supply modes and transfusion reactions 0.8%. CONCLUSIONS: O&G clinicians order blood according to clinical need and transfuse 85% of the products supplied. Product supply did not significantly affect use although appropriateness of transfusion was difficult to assess.

Deuterium uptake in magnetic-fusion devices with lithium-conditioned carbon walls.

Lithium wall conditioning has lowered hydrogenic recycling and dramatically improved plasma performance in many magnetic-fusion devices. In this Letter, we report quantum-classical atomistic simulations and laboratory experiments that elucidate the roles of lithium and oxygen in the uptake of hydrogen in amorphous carbon. Surprisingly, we show that lithium creates a high oxygen concentration on a carbon surface when bombarded by deuterium. Furthermore, surface oxygen, rather than lithium, plays the key role in trapping hydrogen.

Hepatitis E virus infection in Ghanaian blood donors - the importance of immunoassay selection and confirmation.

BACKGROUND AND OBJECTIVES: Hepatitis E virus (HEV) infection is emerging as a potential new threat to blood safety after several cases of transfusion-transmission were reported from non-epidemic countries. On the basis of seroprevalence data, HEV is endemic in Ghana where poor sanitary conditions and regular flooding are prevalent. However, no data are available for HEV prevalence in blood donors. MATERIALS AND METHODS: Plasma samples from 239 Ghanaian blood donors were tested for anti-HEV IgG and IgM by ELISA (two and three assays, respectively) and Western blot (recomLine) and for HEV-RNA by RT-qPCR. RESULTS: All donors were RNA negative. Results from the different serological assays were discrepant: reactivity in two of the three IgM assays was correlated with elevated IgM levels, but the discrepancies between IgG assays were unrelated to the donors' IgG levels and more likely related to assay sensitivity. Fourteen samples (5·9%) were anti-HEV IgM reactive and 11 samples (4·6%) anti-HEV IgG reactive in at least two serological assays from different manufacturers. CONCLUSIONS: (a) In the absence of accepted confirmatory assays, it is crucial to confirm anti-HEV reactive samples with an alternative assay, especially when the population tested carries high levels of immunoglobulin M. (b) Although asymptomatic HEV infections are common in Ghanaian blood donors, currently, it does not seem to be a major risk to blood safety.

Materials analysis and particle probe: a compact diagnostic system for in situ analysis of plasma-facing components (invited).

The objective of the materials analysis particle probe (MAPP) in NSTX is to enable prompt and direct analysis of plasma-facing components exposed to plasma discharges. MAPP allows multiple samples to be introduced to the level of the plasma-facing surface without breaking vacuum and analyzed using X-ray photoelectron spectroscopy (XPS), ion-scattering and direct recoil spectroscopy, and thermal desorption spectroscopy (TDS) immediately following the plasma discharge. MAPP is designed to operate as a diagnostic within the ∼12 min NSTX minimum between-shot time window to reveal fundamental plasma-surface interactions. Initial calibration demonstrates MAPP's XPS and TDS capabilities.

Current incidence and residual risk of HIV, HBV and HCV at Canadian Blood Services.

Estimates of the viral residual risk should be updated to reflect current incidence of infection in blood donors. Incidence rates were estimated for allogeneic whole-blood donations made to Canadian Blood Services from 2006 to 2009 based on transmissible disease conversions of repeat donations within a 3-year period. Residual risk was estimated as the incidence multiplied by the window period. The residual risk of HIV was 1 per 8 million donations, HCV 1 per 6·7 million donations and HBV 1 per 1·7 million donations. The residual risk remains low and has decreased for HCV since our previous estimates due to reduced incidence.

HIV-1 subtypes D and F are prevalent in Guinea Conakry.

BACKGROUND: Limited data is available upon the distribution of different HIV-1/2 genotypes in the blood donor population from Guinea Conakry. OBJECTIVES: To investigate the prevalence of HIV-1/2 subtypes in asymptomatic blood donors in Guinea Conakry, in order to update knowledge of HIV-1/2 epidemiology within this country. STUDY DESIGN: Samples from 104 blood donors seropositive for HIV-1/2 were tested for HIV-1 by real-time RT-PCR. Those negative for HIV-1 were tested with HIV-2 nested RT-PCR. Positive samples were further amplified in the HIV-1 gag and pol regions and sequenced. Subtypes were determined by phylogenetic analysis on amplicon sequences. RESULTS: 61 samples were positive by HIV-1 real-time RT-PCR. Of the 43 negative, 2 (4.6%) were positive for HIV-2. 52/61 (85.3%) samples were positive by nested RT-PCR. Of the 52, 43 (70.5%) and 31(59.6%) sequences were obtained in the gag and pol regions, respectively; 23 for both regions. HIV-1 subtype distribution was 1 B (2.1%), 8 F (17%), 8 D (17%) and 28 CRF02_AG (59.6%) with 2 unclassified recombinants (4.3%). Unique clusters for subtype D and F distinguished Guinea from HIV-1 subtype distribution in neighboring countries. CONCLUSIONS: Subtype F and subtype D strains, uncommon in West Africa, are a substantial part of HIV-1 epidemiology in Guinea.

Diversity of hepatitis B virus infecting Malaysian candidate blood donors is driven by viral and host factors.

Malaysia is a medium endemic country for hepatitis B virus (HBV) infection but little is known about HBV strains circulating in Malaysian blood donors. Viral load, HBsAg concentrations and nested PCR products from 84 HBV surface antigen (HBsAg) positive samples were analysed in detail. Median viral load was 3050 IU/mL and median HBsAg 1150 IU/mL. Fifty-six full genome, 20 pre-S/S, 1 S gene and six basic core promoter/precore-only sequences were obtained. Genotypes B and C were present at a ratio of 2:1, and two genotype D samples were obtained, both from donors of Indian background. Phylogenetically, genotype B was more diverse with subgenotypes B2-5, B7 and B8 present, while most genotype C strains were from subgenotype C1. Genotypes B and C were equally frequent in ethnic Malays, but 80% of strains from Chinese were genotype B. HBsAg concentrations were higher in genotype C than in genotype B, in Chinese than Malays and in donors under the age of 30. HBV vaccine escape substitutions (P120S/T, I126N and G145G) were present in six strains. In the large surface protein, immuno-inactive regions were more mutated than CD8 epitopes and the major hydrophilic region. Strains of genotype B or from ethnic Malays had higher genetic diversity than strains of genotype C or from Chinese donors. Hence HBV strains circulating in Malaysia are phylogenetically diverse reflecting the ethnic mix of its population. Ethnic Malays carry lower HBsAg levels and higher genetic diversity of the surface antigen, possibly resulting in more effective immune control of the infection.

HBV reactivation after fludarabine chemotherapy identified on investigation of suspected transfusion-transmitted Hepatitis B virus.

BACKGROUND & AIMS: Multi-transfused patients often receive treatments inducing various levels of immunodeficiency. Acute viral infections may then be attributed either to transfusion-transmitted infection (TTI) or reactivation of a past infection. METHODS: A patient with chronic lymphocytic leukemia (CLL) who had >250 blood donor exposures developed acute Hepatitis B virus (HBV) infection. Routine donor testing for HB core antibodies (anti-HBc) was in place in the relevant period and investigations undertaken on the blood donors were negative. RESULTS: Review of historical, molecular, and antigenic evidence demonstrated reactivation of a recovered HBV infection dating >30 years and the selection of a rare escape mutant that briefly replicated and caused acute liver disease. This mutant was unreactive with several HBsAg assays and poorly reactive with an HBV vaccine plasma. Correcting the C139Y substitution by site directed mutagenesis of recombinant surface proteins re-established assay reactivity. CONCLUSIONS: Fludarabine, but not Chlorambucil, appeared sufficiently immunosuppressive to trigger reactivation despite low levels of neutralizing antibodies. Differentiating between TTI and reactivation of HBV becomes more challenging with the increasing frequency of immunocompromised blood recipients. Chemotherapy with Fludarabine alone should be considered as carrying high risk of viral reactivation. Pre-treatment testing and peripheral blood sample archiving may be indicated in HBsAg negative patients.