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ABSTRACT: 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.
Transfusion Medicine 05/2013; · 1.14 Impact Factor
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ABSTRACT: 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.
Physical Review Letters 03/2013; 110(10):105001. · 7.37 Impact Factor
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ABSTRACT: 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.
The Review of scientific instruments 10/2012; 83(10):10D703. · 1.52 Impact Factor
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ABSTRACT: 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.
Vox Sanguinis 07/2012; · 2.86 Impact Factor
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ABSTRACT: Sn+ irradiations of Ru single-layer mirrors (SLM) simulate conditions of fast-Sn ion exposure in high-intensity 13.5 nm lithography
lamps. Ultra-shallow implantation of Sn is measured down to 1–1.5 nm depth for energies between 1–1.3 keV at near-normal incident
angles on Ru mirror surfaces. The Sn surface concentration reaches an equilibrium of 55–58% Sn/Ru for near-normal incidence
and 36–38% for grazing incidence at approximately 63 degrees with respect to the mirror surface normal. The relative reflectivity
at 13.5nm at 15-degree incidence was measured in-situ during Sn+ irradiation. For near-normal Sn+ exposures the reflectivity is measured to decrease between 4–7% for a total Sn fluence of 1016 cm−2. Theoretical Fresnel reflectivity modeling shows for the same fluence assuming all Sn atoms form a layer on the Ru mirror
surface, that the reflectivity loss should be between 15–18% for this dose. Ex-situ absolute 13.5 nm reflectivity data corroborate
these results, indicating that implanted energetic Sn atoms mixed with Ru reflect 13.5-nm light differently than theoretically
predicted by Fresnel reflectivity models.
Applied Physics A 04/2012; 100(1):231-237. · 1.63 Impact Factor
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ABSTRACT: Lithium evaporation onto National Spherical Torus Experiment (NSTX) plasma-facing components (PFCs) has resulted in improved energy confinement, and reductions in the number and amplitude of edge-localized modes (ELMs) up to the point of complete ELM suppression. The associated PFC surface chemistry has been investigated with a novel plasma–material interface probe connected to an in-vacuo surface analysis station. Analysis has demonstrated that the binding of D atoms to the polycrystalline graphite material of PFCs is fundamentally changed by lithium—in particular, deuterium atoms become weakly bonded near lithium atoms themselves bound to either oxygen or the carbon from the underlying material. Surface dust inside NSTX has been detected in real time using a highly sensitive electrostatic dust detector. In a separate experiment, electrostatic removal of dust via three concentric spiral-shaped electrodes covered by a dielectric and driven by a high-voltage three-phase waveform was evaluated for its potential application to fusion reactors.
Physica Scripta 12/2011; 2011(T145):014020. · 1.20 Impact Factor
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R. Raman,
J-W. Ahn, J.P. Allain,
R. Andre,
R. Bastasz,
D. Battaglia,
P. Beiersdorfer,
M. Bell,
R. Bell,
E. Belova, [......],
K.L. Wong,
J. Wright,
Z. Xia,
D. Youchison,
G. Yu,
H. Yuh,
L. Zakharov,
D. Zemlyanov,
G. Zimmer,
S.J. Zweben
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ABSTRACT: In the last two experimental campaigns, the low aspect ratio NSTX has explored physics issues critical to both toroidal confinement physics and ITER. Experiments have made extensive use of lithium coatings for wall conditioning, correction of non-axisymmetric field errors and control of n = 1 resistive wall modes (RWMs) to produce high-performance neutral-beam heated discharges extending to 1.7 s in duration with non-inductive current fractions up to 0.7. The RWM control coils have been used to trigger repetitive ELMs with high reliability, and they have also contributed to an improved understanding of both neoclassical tearing mode and RWM stabilization physics, including the interplay between rotation and kinetic effects on stability. High harmonic fast wave (HHFW) heating has produced plasmas with central electron temperatures exceeding 6 keV. The HHFW heating was used to show that there was a 20–40% higher power threshold for the L–H transition for helium than for deuterium plasmas. A new diagnostic showed a depletion of the fast-ion density profile over a broad spatial region as a result of toroidicity-induced Alfvén eigenmodes (TAEs) and energetic-particle modes (EPMs) bursts. In addition, it was observed that other modes (e.g. global Alfvén eigenmodes) can trigger TAE and EPM bursts, suggesting that fast ions are redistributed by high-frequency AEs. The momentum pinch velocity determined by a perturbative technique decreased as the collisionality was reduced, although the pinch to diffusion ratio, Vpinch/χ, remained approximately constant. The mechanisms of deuterium retention by graphite and lithium-coated graphite plasma-facing components have been investigated. To reduce divertor heat flux, a novel divertor configuration, the 'snowflake' divertor, was tested in NSTX and many beneficial aspects were found. A reduction in the required central solenoid flux has been realized in NSTX when discharges initiated by coaxial helicity injection were ramped in current using induction. The resulting plasmas have characteristics needed to meet the objectives of the non-inductive start-up and ramp-up program of NSTX.
Nuclear Fusion 08/2011; 51(9):094011. · 4.09 Impact Factor
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ABSTRACT: Background Despite continuous technical improvement in blood donation testing, hepatitis B infection remains a major risk of transfusion-transmitted viral infection. The residual risk of hepatitis B virus (HBV) transmission is related to the pre-seroconversion window period (WP), infection with immunovariant viruses, and with occult carriage of HBV infection (OBI).Results and discussion Reduction of HBV residual risk is achieved by developing more sensitive HBsAg test, by adopting anti-HBc screening when appropriate, and recently by implementing HBV nucleic acid testing (NAT), either in minipools or more efficiently in individual donations. Compared with serological testing, HBV NAT combines the ability to significantly reduce the window period and to detect OBIs. Clinical observations suggest lower transmission rate of occult HBV than WP. Lower transmission rate might be related to the low viral load generally observed in OBI donors or to the presence of defective variants associated with occult carriage. In addition, there is evidence that OBI-infected donors carrying neutralizing anti-HBs (∼50%) are unlikely to be infectious, while those with anti-HBc only may be more infectious especially in immunocompromised recipients. Immunodeficient elderly and patients receiving immunosuppressive treatments (organ transplantation or cancer chemotherapy) may be susceptible to infection with lower infectious dose even in the presence of anti-HBs. There is no evidence that blood from anti-HBc only positive/HBV DNA-negative donors is infectious. Present evidence suggests that the association of HBsAg and sensitive NAT screening adequately covers risks of HBV transfusion–transmission, allowing to dispense or discontinue anti-HBc screening, avoiding discarding non-infectious and precious blood units, particularly in high prevalence areas. Identification of ‘post-transfusion’ HBV infection relies essentially on clinical evidence of acute infection or on look-back exercises following the identification of HBV DNA-positive donations. To protect from HBV infection the increasing number of immunodeficient recipients, maximum sensitivity of HBV NAT is required. As these recipients are also at risk of viral reactivation when previously exposed, anti-HBc testing and storage of a pre-transfusion sample when anti-HBc-positive would prevent the difficulties of differentiating between transfusion–transmission and reactivation.
ISBT Science Series 05/2011; 6(1):234 - 240.
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ABSTRACT: Lithium wall conditioning has been found to enhance plasma performance for graphite walled fusion devices such as TFTR, CDX-U, T-11M, TJ-II and NSTX. Among observed plasma enhancements is a reduction in edge density and reduced deuterium recycling. The mechanism by which lithiated graphite retains deuterium is largely unknown. Under controlled laboratory conditions, X-ray photoelectron spectroscopy (XPS) is used to observe the chemical changes that occur on ATJ graphite after lithium deposition. The chemical state of lithiated graphite is found to change upon deuterium irradiation indicating the formation Li-O-D, manifest at 532.9 ± 0.6 eV. Lithium-deuterium interactions are also manifest in the C 1s photoelectron energy range and show Li-C-D interactions at 291.2 ± 0.6 eV. Post-mortem NSTX tiles that have been exposed to air upon extraction are cleaned and examined, revealing the chemical archaeology that formed during NSTX operations. XPS spectra show strong correlation (± 0.3 eV) in Li-O-D and Li-O peaks from post-mortem and control experiments, thus validating offline experiments. We report findings that show that deuterium is found to interact with lithium after lithium has already reacted with carbon and oxygen.
Journal of Applied Physics 03/2011; 109(5):053306-053306-6. · 2.17 Impact Factor
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ABSTRACT: 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.
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.
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.
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.
Journal of Hepatology 10/2010; 53(4):780-7. · 9.26 Impact Factor
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ABSTRACT: In 2008, hepatitis B virus (HBV) DNA testing was not yet mandatory for the screening of blood donations in Switzerland. At that time, HBsAg was the only specific mandatory marker for HBV. The importance of high sensitivity for HBV NAT screening is shown.
Donor and recipient of a transfusion-transmitted HBV infection were followed up. Multiple samples were tested for HBV serological and molecular markers.
At donation, the donor appeared healthy, HBsAg was negative and had a normal ALAT level. Ten weeks later, clinical symptoms suggested acute HBV infection as was confirmed with positive HBsAg, HBeAg, anti-HBc IgG, anti-HBc IgM and anti-HBe. The archived sample from the original donation was negative for anti-HBc, but positive for HBV DNA (17 IU/ml). A recipient transfused with the red cell concentrate was HBV DNA positive (3100 IU/ml) 3 months post-transfusion. After five months, HBsAg, HBeAg, anti-HBc and HBV DNA (1.1 x 10(11) IU/ml) were positive. Two weeks later, the patient died from complications associated with HBV infection and his underlying bone marrow disease.
The present case illustrates the importance of introducing highly sensitive HBV NAT screening strategy to prevent possible HBV transfusion-transmitted infections from donors with low viral load.
Vox Sanguinis 05/2010; 98(4):504-7. · 2.86 Impact Factor
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ABSTRACT: Most African countries are challenged in recruiting and retaining voluntary blood donors by cost and other complexities and in establishing and implementing national blood policies. The availability of replacement donors who are a cheaper source of blood has not enhanced repeat voluntary donor initiatives.
An overview of activities for recruiting and retaining voluntary blood donors was carried out. Donor records from mobile sessions were reviewed from 2002 to 2008.
A total of 71,701 blood donations; 45,515 (63.5%) being voluntary donations with 11,680 (25%) repeat donations were collected during the study period. Donations from schools and colleges contributed a steady 60% of total voluntary whilst radio station blood drives increased contribution from 10 to 27%. Though Muslim population is less than 20%, blood collection was above the 30-donation cost-effectiveness threshold with a repeat donation trend reaching 60%. In contrast Christian worshippers provided <25 unit/session and 30% repeat donations. Repeat donation trends amongst school donors and radio blood drives were 20% and 70% respectively.
Repeat donations rates have been variable amongst different blood donor groups in Kumasi, Ghana. The impact of community leaders in propagating altruism cannot be overemphasized. Programs aiming at motivating replacement donors to be repeat donors should be developed and assessed.
Biologicals 01/2010; 38(1):47-52. · 1.70 Impact Factor
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H W Kugel,
M G Bell,
H Schneider, J P Allain,
R E Bell,
R Kaita,
J Kallman,
S Kaye,
B P Leblanc,
D Mansfield, [......],
D Mueller,
M Ono,
S Paul,
S Gerhardt,
R Raman,
S Sabbagh,
C H Skinner,
V Soukhanovskii,
J Timberlake,
L E Zakharov
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ABSTRACT: Fusion Engineering and Design j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / f u s e n g d e s a b s t r a c t NSTX high power divertor plasma experiments have used in succession lithium pellet injection (LPI), evaporated lithium, and injected lithium powder to apply lithium coatings to graphite plasma facing components. In 2005, following the wall conditioning and LPI, discharges exhibited edge density reduc-tion and performance improvements. Since 2006, first one, and now two lithium evaporators have been used routinely to evaporate lithium onto the lower divertor region at total rates of 10–70 mg/min for periods 5–10 min between discharges. Prior to each discharge, the evaporators are withdrawn behind shutters. Significant improvements in the performance of NBI heated divertor discharges resulting from these lithium depositions were observed. These evaporators are now used for more than 80% of NSTX dis-charges. Initial work with injecting fine lithium powder into the edge of NBI heated deuterium discharges yielded comparable changes in performance. Several operational issues encountered with lithium wall conditions, and the special procedures needed for vessel entry are discussed. The next step in this work is installation of a liquid lithium divertor surface on the outer part of the lower divertor.
Fusion Engineering and Design. 01/2010; 85:865-873.
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ABSTRACT: We assess key plasma–surface interaction issues of an all-metal plasma facing component (PFC) system for ITER, in particular a tungsten divertor, and a beryllium or tungsten first wall. Such a system eliminates problems with carbon divertor erosion and T/C codeposition, and for an all-tungsten system would better extrapolate to post-ITER devices. The issues studied are sputtering, transport and formation of mixed surface layers, tritium codeposition, plasma contamination, edge-localized mode (ELM) response and He-on-W irradiation effects. Code package OMEGA computes PFC sputtering erosion/redeposition in an ITER full power D–T plasma with convective edge transport. The HEIGHTS package analyses plasma transient response. PISCES and other data are used with code results to assess PFC performance. Predicted outer-wall sputter erosion rates are acceptable for Be (0.3 nm s−1) or bare (stainless steel/Fe) wall (0.05 nm s−1) for the low duty factor ITER, and are very low (0.002 nm s−1) for W. T/Be codeposition in redeposited wall material could be significant (~2 gT/400 s-ITER pulse). Core plasma contamination from wall sputtering appears acceptable for Be (~2%) and negligible for W (or Fe). A W divertor has negligible sputter erosion, plasma contamination and T/W codeposition. Be can grow at/near the strike point region of a W divertor, but for the predicted maximum surface temperature of ~800 °C, deleterious Be/W alloy formation as well as major He/W surface degradation will probably be avoided. ELMs are a serious challenge to the divertor, but this is true for all materials. We identify acceptable ELM parameters for W. We conclude that an all-metal PFC system is likely a much better choice for ITER D–T operation than a system using C. We discuss critical R&D needs, testing requirements, and suggest employing a 350–400 °C baking capability for T/Be reduction and using a deposited tungsten first wall test section.
Nuclear Fusion 02/2009; 49(3):035007. · 4.09 Impact Factor
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ISBT Science Series 04/2008; 3(1):104 - 106.
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ABSTRACT: We have investigated the effect of exposure to thermal Sn atoms on the 13.5-nm specular reflectivity of single-layer Pd mirror
surfaces. The mirror surfaces were characterized using low-energy ion scattering spectroscopy (LEISS) and the relative 13.5-nm
specular reflectivity measured in situ during exposure to doses up to several 1016cm-2 Sn particles. The relative reflectivity loss at 13.5nm is found to deviate from the theoretical Fresnel reflectivity. Losses
are < 20% for fluence levels > 1016cm-2. The difference is due to deposited Sn nucleating at early stages of exposure and coalescing to nanoscale islands. Sn atomic
surface fraction from LEISS reaches 50 a/o (atomic percent) at a fluence of 0.25×1016cm-2 and ultimately levels off at 93–95% for fluences greater than 2.0×1016cm-2. The specular reflectivity approaches the Fresnel theoretical value of 38.7% for thermal Sn deposition at large doses and
equilibrates to 36.4%. The difference is mainly due to surface roughness of the deposited Sn film.
Applied Physics A 03/2008; 91(1):13-16. · 1.63 Impact Factor
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H W Reesink,
C P Engelfriet,
G Henn,
W R Mayr,
G Delage,
F Bernier,
T Krusius,
A Assal,
P Gallian,
C Corbi, [......],
C Niederhauser,
M Stolz, J-P Allain,
S Owusu-Ofori,
R Eglin,
S Stramer,
M Busch,
D M Strong,
J Epstein,
R Biswas
Vox Sanguinis 03/2008; 94(2):153-66. · 2.86 Impact Factor
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Transfusion Medicine 07/2007; 17(3):149. · 1.14 Impact Factor
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J-P Allain
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ABSTRACT: The International Society of Blood Transfusion (ISBT) transfusion-transmitted infections (TTI) working party is proposing to undertake an international collaborative study aimed at understanding occult hepatitis B infection by molecular and immunological characterization, determining infectivity by transfusion and clinical relevance of this newly identified condition. This article provides information to the transfusion community and aims to recruit potential collaborators for the study. Further information can be obtained from the author or the ISBT TTI working group website (http://www.isbt-web.org).
Vox Sanguinis 05/2007; 92(3):254-7. · 2.86 Impact Factor
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Developments in biologicals 02/2007; 127:71-86.
