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SUMMARY Objectives To evaluate the cost‐effectiveness of changing opening times, introducing a donor health report and reducing the minimum inter‐donation interval for donors attending static centres. Background Evidence is required about the effect of changes to the blood collection service on costs and the frequency of donation. Methods/Materials This study estimated the effect of changes to the blood collection service in England on the annual number of whole‐blood donations by current donors. We used donors' responses to a stated preference survey, donor registry data on donation frequency and deferral rates from the INTERVAL trial. Costs measured were those anticipated to differ between strategies. We reported the cost per additional unit of blood collected for each strategy versus current practice. Strategies with a cost per additional unit of whole blood less than £30 (an estimate of the current cost of collection) were judged likely to be cost‐effective. Results In static donor centres, extending opening times to evenings and weekends provided an additional unit of whole blood at a cost of £23 and £29, respectively. Introducing a health report cost £130 per additional unit of blood collected. Although the strategy of reducing the minimum inter‐donation interval had the lowest cost per additional unit of blood collected (£10), this increased the rate of deferrals due to low haemoglobin (Hb). Conclusion The introduction of a donor health report is unlikely to provide a sufficient increase in donation frequency to justify the additional costs. A more cost‐effective change is to extend opening hours for blood collection at static centres.

The internal structure and growth history of six macro-diamonds from kimberlite pipes in Yakutia (Russia) were investigated with cathodoluminescence imaging and coupled carbon isotope and nitrogen abundance analyses along detailed core to rim traverses. The diamonds are characterised by octahedral zonation with layer-by-layer growth. High spatial resolution SIMS profiles establish that there is no exchange of the carbon isotope composition across growth boundaries at the μm scale and that isotopic variations observed between (sub)zones within the diamonds are primary. The macro-diamonds have δ13C values that vary within 2‰ of −5.3‰ and their nitrogen contents range between 0–1334 at. ppm. There are markedly different nitrogen aggregation states between major growth zones within individual diamonds that demonstrate Yakutian diamonds grew in multiple growth events. Growth intervals were punctuated by stages of dissolution now associated with

The use of CVD diamond in electronics has very stringent requirements. For a CVD diamond industry to become viable it is mandatory to obtain very large growth rates (> 5 µm/h), all the while maintaining extremely high purity, a crystalline defect density as low as possible, and large usable surface areas. At the same time, one must keep the stress level within the growing crystal below acceptable limits to avoid crack formation and preserve the crystal structural integrity. These imperatives imply to work to improve both the plasma deposition process and the CVD diamond crystal growth. In this paper, we propose a three-pronged approach: (i) We use detailed plasma models to establish the influence of process parameters (in particular deposition pressure) on plasma chemistry in order to optimize film growth rate and diamond quality; (ii) We emphasize the need for careful substrate pre-treatment and selection (including choosing a single-sector face) to minimize defects in the growing films; (iii) We employ a 3D geometrical model to predict the crystal shape under given growth conditions, and exploit this knowledge to devise a growth strategy maximizing the usable film surface area while minimizing stresses inside the films.

The use of diamond as a material for high power electronics requires high-purity monocrystalline thick diamond films. Hence it is extremely important to have perfect control of the morphology during the entire growth process, so that the useable surface be maximized and residual stresses (which may cause cracking of the sample during the growth process) be limited. To assist in this work, a 3D geometric growth model has been recently developed, taking into account the growth rate of the different crystallographic planes: {100}, {110}, {111}, and {113}. The knowledge of the growth rate along the different directions as a function of growth parameters (substrate temperature, methane concentration, and nitrogen content in the gas phase) was the missing link between simulations and effective thick film processing. This knowledge is here embodied in the measurements displayed in this paper. In particular, we report on a way of limiting the occurrence of specific facets with deleterious effects on stress and crystal cracking probability.

The quality of single crystal diamond obtained by microwave CVD processes has been drastically improved in the last 5 years thanks to surface pretreatment of the substrates [A. Tallaire, J. Achard, F. Silva, R.S. Sussmann, A. Gicquel, E. Rzepka, Physica Status Solidi (A) 201, 2419-2424 (2004); G. Bogdan, M. Nesladek, J. D'Haen, J. Maes, V.V. Moshchalkov, K. Haenen, M. D'Olieslaeger, Physica Status Solidi (A) 202, 2066-2072 (2005); M. Yamamoto, T. Teraji, T. Ito, Journal of Crystal Growth 285, 130-136 (2005)]. Additionally, recent results have unambiguously shown the occurrence of (110) faces on crystal edges and (113) faces on crystal corners [F. Silva, J. Achard, X. Bonnin, A. Michau, A. Tallaire, O. Brinza, A. Gicquel, Physica Status Solidi (A) 203, 3049-3055 (2006)]. We have developed a 3D geometrical growth model to account for the final crystal morphology. The basic parameters of this growth model are the relative displacement speeds of (111), (110) and (113) faces normalized to that of the (100) faces, respectively alpha, beta, and gamma. This model predicts both the final equilibrium shape of the crystal (i.e. after infinite growth time) and the crystal morphology as a function of alpha, beta, gamma, and deposition time. An optimized operating point, deduced from the model, has been validated experimentally by measuring the growth rate in (100), (111), (110), and (113) orientations. Furthermore, the evolution of alpha, beta, gamma as a function of methane concentration in the gas discharge has been established. From these results, crystal growth strategies can be proposed in order, for example, to enlarge the deposition area. In particular, we will show, using the growth model, that the only possibility to significantly increase the deposition area is, for our growth conditions, to use a (113) oriented substrate. A comparison between the grown crystal and the model results will be discussed and characterizations of the grown film (Photoluminescence spectroscopy, EPR, SEM) will be presented. (C) 2008 Elsevier B.V. All rights reserved.

Recent interests in freestanding single-crystal CVD diamond (SC-CVD) discs for several applications in electronics led to an intense study of SC-CVD layer growth and properties. In this work we have investigated the growth mechanism of monocrystalline CVD diamond films with surfaces smooth in nanometer scale taking into account the defect incorporation in the SC-CVD layers. Specifically we discuss the surface structure characteristics for these conditions as studied with high-resolution AFM mapping. The as-grown CVD layers were removed from the substrate by laser cutting, followed by a polishing step, yielding freestanding plates. Subsequently, microscopic and colour studies as well as infrared absorption spectroscopy were performed. These investigations revealed the presence of several characteristic defects and impurities.

Characteristic features of in situ diamonds can be used to retrace diamond formation during ultrahigh pressure (UHP) metamorphism of the Kokchetav Massif, Kazakhstan. These features include the nitrogen aggregation state in diamond, dissolution features observed on diamond surfaces, and the carbon and nitrogen isotopic composition of the diamonds. The minerals in which the diamonds are included provide additional information and support the view that at least some of the Kokchetav microdiamonds are the products of prograde or peak UHP metamorphism. The coexistence of diamond and graphite is evaluated within this framework.

Microdiamonds from garnet clinopyroxenites of the Kokchetav massif (northern Kazakhstan) and associated alluvial diamonds have been investigated using infrared spectroscopy. All diamonds have high nitrogen contents (from 747 up to 4488 ± 20% at. ppm) and are of type Ib-IaA. Nitrogen data are consistent with a diamond formation over a narrow temperature range. Microdiamonds from garnet clinopyroxenites are characterized by water and carbonate inclusions, similar to those ocurring in fibrous coated diamonds from kimberlite, which suggest that diamonds grew from a C-H-O fluid. In contrast, alluvial microdiamonds do not contain any carbonate inclusions and H2O is absent or present in only minor amounts. Alluvial diamonds are considerably more N-rich but have a similar range of nitrogen aggregation states. It is suggested that alluvial diamonds belong to a separate diamond population compared with the microdiamonds from garnet clinopyroxenites. The Kokchetav microdiamonds are distinct from kimberlitic fibrous diamonds in that they contain abundant Ib centres, have high nitrogen contents and show different populations depending on host rock type. These characteristics support a metamorphic origin for the microdiamonds from the UHPM rocks of the Kokchetav massif.

Low-quality polycrystalline natural diamonds become black when annealing them in an inert atmosphere at sufficiently high temperatures. Different carbon phases (the coexistence of diamond, graphite and amorphous carbon) are identified after this treatment using Raman spectroscopy. Internal structural changes in the microstructure upon annealing are reported and defects are characterised by transmission electron microscopy (TEM) analysis.

In this paper the performance of laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) for the fingerprinting of diamonds of different deposits has been evaluated. The results show that, after optimization of the experimental conditions, the LA unit used (a homogenized 193 nm excimer laser with a flat-top beam profile) is capable of controlled ablation of the diamonds and the sensitivity of the ICP-MS device suffices for the detection of more than ten elements. 31 diamonds originating from four different mines—Premier (South Africa), Orapa (Botswana), Udachnaya (Russia) and Panda (Canada)—were the subject of the study. Every diamond was ablated on 8 different spots for 30 s (crater diameter: 120 µm; energy output: 200 mJ; repetition rate: 20 Hz) and the median of the eight integrated signals was considered as the representative value for subsequent statistical analysis. Under these conditions, the total mass of material removed from a single diamond was ∼16 µg. Finally, 9 elements were selected for fingerprinting purposes (Al, Hg, Na, Ni, Pb, Sb, Sn, Ti and Zn) and different pattern recognition techniques (ternary plots, cluster analysis and partial least squares analysis) were used in order to classify the data. The results obtained can be considered as promising, especially for the partial least squares approach, providing that appropriate data standardization is carried out.

The biotransformation of chloramphenicol in the ruminant forestomachs was studied by incubating the antibiotic with ovine rumen contents in vitro. Differential centrifugation of rumen contents showed that rapid reduction of the aromatic nitro group of chloramphenicol to an arylamine occurred in those fractions containing ciliates, and this activity was not inhibited by penicillin or streptomycin. It is concluded that in adult ruminants, chloramphenicol is metabolised by rumen microfauna more rapidly than it is absorbed, when administered orally.

ummary Chloramphenicol plasma levels were measured in adult cattle, sheep and horses after oral and intramuscular administration of a single dose of 10 mg. chloramphenicol/kg. body weight. The chloramphenicol powder and its palmitate were given orally. With an interval of 1 week chloramphenicol was also injected intramuscularly at two injection sites in the cervical muscle as a 20 % solution. After oral administration of chloramphenicol levels were found in the plasma in horses only. The mean maximum value of 0.6 microgram/ml. was reached half an hour later. In vitro studies with rumen contents of sheep indicated that chloramphenicol was degraded rapidly by the rumen microorganisms. Intramuscular injection however, provoked in all animals examined measurable blood levels of chloramphenicol, which with regard to the maximal level and the course of time, differed from species to species. After intramuscular injection an average maximal value of 1.7 microgram/ml. was attained at three to six hours in cattle. The corresponding level in sheep was 4.1 microgram/ml. at one hour and 0.9 microgram/ml. during the first three hours in horses. It is widely accepted that the minimal therapeutic blood level of chloramphenicol should be 5 microgram/ml. This blood concentration was never attained with a 10 mg./kg. dose rate. This level of antibiotic, however, needs serious investigation. Zusammenfassung Plasma-Chloramphenicol-Spiegel nach oraler und intramuskularer Anwendung bei Pferden, Rindern und Schafen Bei Pferden, Rindern und Schafen wurden die Plasma-Chloramphenicol-Spiegel nach einmaliger oraler und intramuskularer Verabreichung von 10 mg Chloramphenicol/kg Korpergewicht bestimmt. Das Chloramphenicol wurde oral als Base und als Palmitat verabreicht. Von einer 20 %igen Losung (Leukomycine® Bayer) wurden acht Tage spater 10 mg/kg an zwei Stellen tief in den Nackenmuskeln injiziert. Nach oraler Behandlung konnte nur im Plasma von Pferden Chloramphenicol nachgewiesen werden. Der maximale Gehalt wurde nach einer halben Stunde erreicht und betrug durchschnittlich 0,6 μg/ml. Bei „in vitro” Experimenten mit Panseninhalt von Schafen wurde das Chloramphenicol durch die mikrobielle Flora sehr schnell abgebaut. Die intramuskulare Injektion bewirkte hingegen bei alien Tierarten mesbare Plasmaspiegel, die allerdings hinsichtlich Tierart, sowie maximaler Konzentration und zeitlichem Verlauf sehr unterschiedlich waren. Bei Rindern wurde nach 3–6 Stunden ein maximaler Mittelwert von 1,7 μg/ml, bei Pferden wahrend der ersten drei Stunden ein solcher von 0,9 μg/ml und bei Schafen nach einer Stunde ein solcher von 4,1 μg/ml erreicht. Allgemein wird angenommen, das der minimale therapeutische Blutspiegel von Chloramphenicol 5 μg/ml betragt. Bei einer Dosis von 10 mg/kg wurde diese Blutkonzentration nie erreicht. Das Dosisproblem erfordert weitere Untersuchungen. Resume Taux de chloramphenicol dans le plasma apres usage oral et intramusculaire chez des chevaux, des bovins et des moutons Le taux du chloramphenicol dans le plasma a ete determine chez des chevaux, des bovins et des moutons apres une application unique orale et intramusculaire de 10 mg de chloramphenicol par kg de poids. Le chloramphenicol a ete administre oralement comme base et comme palmitate. Une solution a 20 % (Leukomycine® Bayer) a ete administre huit jours plus tard a raison de 10 mg/kg dans deux endroits profonds de la musculature. Le chloramphenicol n'a ete mis en evidence que dans le plasma des chevaux apres le traitement oral. La quantite la plus grande fut atteinte apres une demi-heure et etait en moyenne de 0,6 μg/ml. Le chloramphenicol etait tres rapidement degrade par la flore microbienne dans les experiences faites in vitro avec le contenu de la panse de moutons. Le taux mesure dans le plasma lors d'injections intramusculaires etait tres variable quant a sa concentration maximale et a son maintien dans le temps selon l'espece animale. 1,7 μg/ml apres 3–6 heures fut une valeur maximale chez le bovin, 0,9 μg/ml pendant les trois premieres heures chez le cheval et 4,1 μg/ml apres une heure chez le mouton. On admet en general que le taux sanguin therapeutique minimal de chloramphenicol est de 5 μg/ml. Cette concentration sanguine n'est pas atteinte avec une dose de 10 mg/kg. Le probleme des doses reclame de nouvelles recherches. Resumen El nivel plasmatico de cloramfenicol tras administracion oral e intramuscular en caballos, vacunos y ovejas En equinos, bovinos y ovinos se valoro el nivel de cloramfenicol plasmatico tras administracion unica oral e intramuscular de 10 mg. cloramfenicol/kg. peso en pie. El cloramfenicol se facilito por via oral como base y como palmitato. Ocho dias mas tarde se inyectaron en dos sitios profundus de los musculos nucales 10 mg./kg. de una solucion al 20% (Leucomicina® Bayer). Tras el tratamiento oral solo se pudo identificar cloramfenicol en el plasma de caballos. El contenido maximo se alcanzo al cabo de media hora y era del orden de 0.6 μg./ml. En experimentos in vitro con contenido ruminal de ovejas se desintegra el cloramfenicol muy rapidamente por la flora microbiana. Ahora bien, la inyeccion intramuscular ocasionaba en todas las especies animates niveles plasmaticos mensurables, los cuales variaban sin embargo mucho con respecto a la especie animal, la concentracion maxima y el curso temporal. En bovinos se alcanzo tras 3–6 horas un valor medio maximo de 1.7 μg./ml., en caballos durante las tres horas primeras uno de 0.9 μg./ml. y en ovejas al cabo de una hora uno de 4.1 μg./ml. Se admite en general que el nivel terapeutico minimo en sangre de cloramfenicol es del orden de 5 μg./ml. Con una dosis de 10 mg./kg. no se alcanzo nunca esta concentracion en sangre. Tiene que seguir investigandose el problema de la dosificacion.