Search

Hot isostatic pressing (HIP) is a secondary process used to increase the density of metal injection molding (MIM) components after sintering. MIM is ideal for HIP since MIM results in an as-sintered microstructure without connected pores. This chapter explains the HIP process, describes the benefit of HIP, and also defines the potential issues using HIP. Additionally, example HIP conditions are given for several MIM alloys.

The introduction of mesogenic substituents on polymer backbones facilitates the formation of materials with anisotropic properties. At the same time the polymer chains are connected each other through these substituents in a transient network. The properties of the polymer material, such as the mechanical response or conductivity, are modified by the presence of the liquid-crystalline groups and can be tuned by changing the organisation of the mesogenic groups. Crosslinking the polymer in the liquid-crystalline state induces the manifestation of some memory effect. These phenomena were used for improving the mechanisms of recognition in molecular imprinted materials. Copyright © 2006 Society of Chemical Industry

Metal injection molding (MIM) is a near net-shape process that offers the unique ability to manufacture porous components with homogeneous porosity, pore structure and permeability. MIM is a process that can significantly reduce production cost when large quantities of components with complex shape need to be delivered. In this study, MIM is used to produce porous 316L stainless steel structure from both water and gas atomized powders. The porous components made by MIM were characterized to evaluate their suitability for small pore structure applications. The porous structures were analyzed for porosity, pore size, permeability, and thermal conductivity as a function of powder type and processing conditions. A typical MIM powder (

In this study, a correlation between green part dimensional variation and feedstock viscosity variation is presented for the powder injection moulding (PIM) manufacturing process. A correlation of an increase in green part dimensional variation as feedstock viscosity variation increases has been found and the correlation was independent of powder type (316L gas atomised and water atomised) and mixing technique (batch and continuous). The variation of feedstock viscosity was lowest over the greatest temperature range for high shear continuous compounding with a broad distribution of irregularly shaped powder. Thus, this feedstock material would have the greatest process window for injection moulding with the least variation.

In this study, the effect of powder characteristics and their variability on the dimensional variability of green and sintered PIM components has been examined for 316L stainless steel. Three lots of gas atomised and three lots of water atomised powders were characterised and used to make six batches of PIM compound. These compound lots were injection moulded using a cavity pressure transducer and screw position regulation controls. The moulded geometry was measured in the green state and sintered state for dimensional variability. The general findings are that gas atomised powder produce less dimensional variability than the water atomised powder from lot to lot, however, the water atomised powders produce less in lot dimensional variability and are generally less susceptible to distortion of cantilevered members during sintering. Also, the lot to lot variation in the powder characteristics, such as particle size and pycnometer density, have an effect on dimensional stability whereas variations ...

Dimensional change during solvent debinding is linked to defects such as cracking and slumping in powder injection moulded components. Owing to the delicate condition of the compact during debinding, considerable difficulty exists in determining the magnitude and cause of swelling or shrinkage. Previous studies of this dimensional change have used measurement techniques involving contact or force on the sample, which may alter the behaviour. This study observes in situ dimensional change during solvent debinding using a non-contact laser dilatometer. Dimensional change was investigated for iron and stainless steel powder injection moulded bars with wax-polymer binders. The effects of solvent temperature, paraffin wax content, paraffin wax density, particle size and solids loading were analysed. Comparisons between the dimensional change and mass loss observations during solvent debinding suggest a relationship between the two phenomena based on soluble polymer swelling.

The enzymatic synthesis of trieicosapentaenoylglycerol from glycerol and eicosapentaenoic ethyl ester in a solvent-free medium is studied here. Novozym SP 435 (immobilized lipase from Candida antarctica) has appeared as a very efficient biocatalyst for this transesterification. A nitrogen bubbling has allowed a good mixing and also the shifting of the reaction toward synthesis by eliminating the ethanol formed. The effect of temperature and of the quantity of lipase has been studied. In the optimal conditions (T=80°C, 5% (w/w) of lipase, 1 mol glycerol for 3 mol ethyl ester), pure triglyceride has been obtained after 10 h.

In response to local concerns about the expanding Southland dairy herd, a 4-year study was initiated in 1995 with the primary objective of quantifying nitrate-N losses to waterways from intensively grazed cattle pastures. Treatments were annual N fertiliser inputs of 0, 100, 200 or 400 kg N/ha. Stocking rate was set according to the pasture production on each of these four treatments, and over the 4 years of study ranged between the equivalent of 2.0 cows/ha for the 0N treatment, to 3.0 cows/ha for the treatment receiving 400 kg N/ ha/year. Mean annual losses of nitrate-N in drainage were 30, 34, 46 and 56 kg N/ha for the 0, 100, 200 and 400 kg N/ha/year treatments, respectively. Corresponding mean nitrate-N concentrations in drainage waters were 8.3, 9.2, 12.5 and 15.4 mg/ l, respectively. Very little direct leaching of fertiliser N was observed, even for drainage events in early spring, shortly after urea fertiliser application. The increased nitrate-N losses at higher rates of N fertiliser addition were instead owing to the indirect effect of increasing returns of urine and dung N to pasture. In Years 2 and 3, leaching losses of Ca, Mg, K, Na and sulphate-S averaged 61, 9, 11, 28 and 17 kg/ha/year, respectively, in the 0N fertiliser treatment. Increasing fertiliser N inputs significantly increased calcium and, to a lesser extent, potassium leaching losses but had no effect on losses of other plant nutrients. Surface runoff losses of Total-P, nitrate-N and ammonium- N were less than 0.5 kg/ha/year. For this well-drained Fleming soil, surface runoff was a relatively minor contributor of N to surface water, even for plots receiving high rates of fertiliser N and at a stocking rate of 3.0 cows/ha. Extrapolating these results to a 'typical' dairy pasture in Eastern Southland would suggest that the safe upper limit for annual fertiliser N additions to this site to achieve nitrate in drainage water below the drinking water standard is approximately 170 kg N/ha. Although losses of Ca in drainage were large, returns of this nutrient in maintenance applications of superphosphate-based products and lime should ensure Ca deficiencies are avoided in Southland dairy pastures. Keywords: cation-anion balances, dairy, N fertiliser, nitrate leaching, surface runoff, Southland

The oxidation degree of a commercial silicon carbide (SiC) powder was studied by means of Fourier transform infrared spectroscopy, using the intensity of the δ (SiO 2 ) band at 450 cm −1 for measurements. Results are related to data obtained by LECO and gravimetric measurements. The influence of water in oxygen on the rate of the oxidation process was particularly examined. It was found that water alone had an oxidizing efficiency and that its mixture with oxygen increased the effect of the latter. The presence of Rh particles on SiC promoted the formation of SiO 2 . However, as shown by the IR study of CO adsorption, this formation embedded the metal particles. This effect can be avoided by loading Rh on a precalcined SiC sample.

In France for several years, many patients have been treated in Blood Transfusion Centers belonging to the EFS. This partnership between public hospitals and EFS is appreciated by the patients who find a competent staff in transfusion and apheresis process, in a more pleasant environment than in hospital. There is a total of 93 Health Care Units in Blood Transfusion Centers. Sixty-three of these Health Care Units perform only transfusions and bleeding. In the remaining 30 Health Care Units apheresis, peripheral blood hematopoietic stem, cell harvesting, plasmatic exchanges and extracorporeal photopheresis are also performed. Despite the perfect fit between hospital needs, comfort and easiness for patients, an economical problem remains. At the present time, the reimbursement rate by national health insurance is below the real cost. If unsolved, this discrepancy could force an end to this beneficial partnership.

The iron deficiency is the first cause of anaemia. In healthy young adult, anemia is well tolerated because of its progressive installation. The most common symptoms of anemia are pallor, fatigue and dyspnea. In biological exams, anemia is classically associated with microcytosis and hypochromia. The origins of microcytic anemia are iron deficiency, inflammatory aetiologies, thalassemia and sideroblastic anaemia. The iron-deficiency diagnosis includes two explorations: biological and clinical. The biological exploration is based on interpretation of serum biologics tests as blood iron, ferritin, transferrin with saturation, total iron-binding capacity and its soluble receptors. This interpretation is simple if it is not associated with clinical disorders influencing the internal iron cycle. The clinical exploration must always be followed by a careful assessment of the underlying cause as blood loss. The most common causes in women of reproductive age are gynaecologic. In men and menopausal women, the gastrointestinal tract bleeding is source of anemia. Therapeutic management of anemia is oral iron therapy. Etiological diagnostic of microcytosis is essential before iron therapy. If not, the treatment could be inefficient or it could mask or delay the etiological diagnostic.

The purpose of this study of patients with pancytopenia in Republic of Djibouti was to identify etiologic factors and attempt to define diagnostic and therapeutic strategies adapted to local conditions. Clinical, biological and radiological assessment was performed in 81 patients hospitalized for pancytopenia. There were 56 men and 25 women. Mean hemoglobin, leukocyte and platelet rates were 56,5 +/- 22,7 g/l, 2,1 +/- 0,7.g/l and 56,2 +/- 24,7 g/l respectively. Vitamin deficiency was the most common cause of pancytopenia (49%), followed by hypersplenism (9%), HIV infection (6%) and leishmaniasis (6%). Vitamin-deficient patients had significantly more severe anemia and thrombopenia and significantly higher mean corpuscular volume than patients with pancytopenia related to other causes. Hemoglobin rate lower than 40 g/L and platelet rate lower than 35 G/L showed a positive predictive values of 90% and 100% respectively for a vitamin deficient pancytopenia. Vitamin deficiency is the most frequent etiology of pancytopenia and causes the most severe cytopenia in Djibouti. Rapid vitamin supplementation after minimal etiologic assessment including a myelogram is an effective treatment strategy for this public health problem.

In this work, the authors performed the experimental and numerical study of a real product realized with metal injection molding. The feedstock material (AISI 316 powder and binder) was initially characterized with specific tests in order to identify viscosity, pressure–volume–temperature and thermal properties. This data were then elaborated using a genetic algorithm approach to fit mathematical material models to use for finite element analysis with a commercial software normally employed for thermoplastic injection molding. At the same time, real part fabrication was performed with the process parameters used for numerical simulations in order to validate numerical results from qualitative and quantitative point of view.

Pharmacological doses of all- trans retinoic acid promote G0/G1 transition and G1 arrest of normal human marrow CD34+ cells

Introduction Les indices predictifs d’echec de sevrage de la ventilation mecanique (VM) ont pour objectif de diminuer la morbi-mortalite imputable aux echecs ou aux retards d’extubation. Le score LUS (Lung Ultrasound Score) est un indice recemment decrit, base sur l’echographie pulmonaire. L’interet de ce score dans la prediction des echecs de sevrage n’a ete evalue que dans une etude, portant sur une population de patients ne souffrant pas de broncho-pneumopathie chronique obstructive (BPCO). L’objectif de notre etude est de valider ce score dans une population de reanimation polyvalente incluant des patients atteints de BPCO. Materiel et methodes Il s’agit d’une etude prospective realisee dans le service de reanimation polyvalente du CHU de Reims, du 1er juin au 31 decembre 2013, et ayant recu l’accord du comite d’ethique local. Les mesures echographiques du score LUS ont ete realisees par un operateur unique (B.C), apres une heure d’epreuve de ventilation spontanee (VS) sur tube. La decision d’extubation a ete prise en aveugle des resultats de l’echographie. Le succes de l’extubation etait defini comme l’absence de reintubation, de recours non-programme a la ventilation non-invasive, ou de deces dans les 48 h. Le score LUS a ete evalue en calculant l’aire sous la courbe ROC (AUC), la sensibilite, la specificite et les rapports de vraisemblances positif (LR+) et negatif (LR−). Les donnees sont presentees sous la forme moyenne ± ecart-type ou rapport [intervalle de confiance 95 %]. Resultats Cinquante et un patients ventiles pendant plus de 48 heures ont ete inclus. La moyenne d’âge est de 59 ± 16 ans et le score IGS moyen est de 46,4 ± 8,4. Soixante et onze pour cent (n = 37) des patients sont des hommes et 36 % (n = 19) de la population presente une BPCO. Soixante-seize pour cent des patients (n = 39) ont ete extubes avec succes et 17 % (n = 9) ont presente un echec de sevrage de la VM. Les donnees de 3 patients, ayant presente un echec d’extubation, non par echec de sevrage de la VM mais par obstruction des voies aeriennes superieures, n’ont pas ete prises en compte. Le score LUS est plus eleve dans la population presentant un echec de sevrage que dans la population extubee avec succes (19 ± 4 vs 13 ± 4, p Discussion Le score LUS est valide dans une population incluant des patients atteints de BPCO. Un score LUS ≥ 19 est un bon index predictif d’echec d’extubation par echec de sevrage de la VM. Un score LUS ≤ 14 est predictif d’un succes de l’extubation.

The diffusion of fission product (Cs) implanted into oxide single crystals (ZrO2 and MgAl2O4) has been studied by using the RBS technique. Implanted crystals were either annealed or post-irradiated with Ar ions at elevated temperatures and the depth profiles of fission products were analyzed. In unirradiated crystals, Cs diffusion occurs above 800°C; Ar irradiation reduces the diffusion temperature down to 600°C.

The structural properties of Zirconia (ZrO2) and spinel (MgAl2O4) single crystals doped by ion implantation with fission products (Cs and I) were investigated by using the Rutherford backscattering and channeling techniques. The implantation process induces a heavy damage in the various sublattices of the ceramic matrices above a fluence of about 1015 at. cm−2, corresponding to a number of displacements per atom (dpa) of about 1–2. Large values of the Cs and I substitutional fractions, attributed to the formation of impurity-vacancy complexes, are obtained at impurity concentrations lower than 0.5 at.%. The substitutional fraction decreases with increasing implantation fluence. This effect, which is more pronounced for I than for Cs ions, is likely due to precipitation or compound formation.

A recently reported cytometric method described the possibility of discriminating apoptotic from necrotic cells using FITC-labelled annexin V and propidium iodide (PI). Nevertheless, the brightness of PI-staining and its extensive spectral emission overlap with phycoerythrin (PE) does not permit the study of a subset of a heterogenous cell population with single laser instrumentation. The surface staining of a subset with PE in a heterogenous cell population therefore requires another exclusion dye to detect necrotic cells. We used 7-amino-actinomycin D (7-AAD) that can be excited by the 488 nm argon laser line. 7-AAD emits in the far red range of the spectrum and 7-AAD spectral emission can be separated from the emissions of FITC and PE. The fluorescence parameters allow characterization of necrotic (7-AAD+ annexin V-FITC+ cells), apoptotic (7-AAD-annexin V-FITC+ cells) and viable cells (7-AAD- annexin V-FITC- cells) in a subset of PE+ cells. The value of this method was demonstrated by measuring apoptosis and necrosis in a model of HL-60 cells exposed to different inducers of cell death. The method was validated by fluorescent cell sorting in combination with morphologic examination of the sorted cells. The technique we present is particularly valuable in a clinical setting because it enables rapid multiparameter analysis of necrosis and early apoptosis in combination with cell surface phenotyping with a single laser. We present the effects of haemopoietic growth factor deprivation on myeloid progenitor CD34+ cells as an example of its application.

Retinoids, especially all-trans-retinoic acid (ATRA), are well known for their differentiating activity on HL-60 cells. Moreover ATRA induces CD38 antigen overexpression on these cells. In this study we examined the effects of ATRA on purified normal CD34+ cells from adult human marrows incubated with ATRA (1 microM) or stem cell factor (SCF) after 7 d liquid cultures in serum-deprived medium. Before and after the incubation, CD34+ cells were studied by flow cytometry to evaluate the cell-surface expression of CD38 and c-Kit antigens and the cycle status of these cells using high-resolution analysis (DNA content v Ki-67 antigen expression) to clarify the functional meaning of antigenic variations. When compared with control cultures, ATRA-treated cells displayed changes in their immunophenotypic profile. Particularly relevant was the up-regulation of CD38 antigen with a mean (+/-SEM) fold increase of 21 +/- 0.1 (P=0.028) for geometric mean fluorescence intensity (GMFI), without modulation of c-Kit expression. SCF only down-regulated expression of c-Kit with a fold decrease of 4.6 +/- 0.9 for GMFI (P=0.043). Unlike SCF, ATRA did not induce CD34+ cells to entry into cell cycle despite increased levels of surface CD38 antigen. Moreover morphological and functional assays did not argue for an ATRA-induced maturation process. Contrary to steady-state cells, CD34+ cells treated with pharmacological doses of ATRA alone displayed CD38 over-expression without change in c-Kit levels and cycle status, suggesting an absence of maturation pressure.

Infrared spectroscopy is a powerful technique to study the adsorption of molecules on well-defined metal surfaces or on metal supported on oxides. In particular for metal characterization. CO is frequently used as the probe molecule because of the high absorption coefficient of the v(CO) mode and the sensitivity of its frequency to the oxidation state of the site, to its geometry and to its coordinative unsaturation degree. For spectra interpretation, it is important to take into account the dipolar coupling effects which induce wavenumber shifts and intensity transfer. In particular, caution should be taken in the characterization of defect sites. By following frequency shifts for various coverages, bandwidths and intensities, CO allows us to specify whether probe molecules form islands or are well-dispersed on the surface. Some examples of all these features are developed for single crystals and for supported metals.

The use of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) as an adjunct to autologous bone marrow transplantation (ABMT) or peripheral blood progenitor cell (PBPC) transplantation was evaluated in 59 lymphoma patients. Patients were divided into three groups. In group I (n = 21) patients received rhGM-CSF (5 micrograms/kg daily) at the time of PBPC collection and during the recovery phase post-infusion. In group II (n = 12) patients received rhGM-CSF as an adjunct to ABMT. In group III (n = 26) they were grafted with bone marrow without rhGM-CSF. Administration of rhGM-CSF (groups I and II) significantly reduced the time to myeloid engraftment, the number of febrile days and the median duration of antibiotics administration and of hospital stay when compared with the group in which patients did not receive rhGM-CSF. The only difference between ABMT and PBPC, given with rhGM-CSF support, was observed in the duration of hospitalization (group Igroup II, P0.05). These data show that rhGM-CSF is highly effective in reducing the duration of aplasia following BMT and PBPC transfusion, and there appears to be little difference in efficacy between these techniques, provided that patients also receive rhGM-CSF.

We compared the release of granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF) and tumor necrosis factor alpha (TNF alpha) in the supernatant of long-term bone marrow cultures (LTBMC) derived from 10 control patients and from 14 patients before and 3 months after autologous bone marrow transplantation (BMT). The three cytokines were spontaneously present in the supernatant of cultures established from patients before and after autologous BMT, while GM-CSF remained undetectable in the supernatants of control patients. The maximal levels of cytokines were produced after the first week and were not statistically different between control, patients before and after grafts although the granulocyte-macrophage colony-forming unit (CFU-GM) production in long-term culture (LTC) was lower in patients after graft compared with control patients (median values at LTC initiation: 32 and 158, respectively, P0.001 and median values of the total production: 510 and 12406, respectively, P0.002). However, GM-CSF was more frequently detected in patients after graft than in control patients. This study demonstrated that the production of GM-CSF, G-CSF and TNF alpha is not impaired in patients after graft (medians 0, 870.5, 173.5 pg/ml and ranges 0-31.2, 0-10 000 and 0-1426, respectively) compared with control patients (medians 0, 69, 66 pg/ml and ranges 0, 0-13 280 and 0-1318, respectively), although patients after graft were shown to have lower marrow CFU-GM counts. These results suggest that the ability of the accessory cells to produce these cytokines was not reduced after autologous BMT.

A study of CFU-GM sensitivity to mafosfamide was carried out in 67 candidates for ABMT. A lethal dose 95 (LD95) was calculated from the dose-response curve. Despite standardized treatment conditions of marrow buffy-coat cells, LD95 values that were normally distributed (median 100 micrograms/ml; mean +/- SEM 95.6 +/- 4.0 micrograms/ml) varied considerably from patient to patient (range 30-160 micrograms/ml). Three independent factors appeared to confer greater sensitivity of CFU-GM: low patient age, low CFU-GM rate in treated cells and prolonged delay of CFU-GM sensitivity test from last chemotherapy course. In contrast, sex, pathology, disease status, number of previous chemotherapies and use of CY before the test did not influence CFU-GM sensitivity. Forty-six patients were autografted with mafosfamide-treated marrows according to their LD95. The mean percentage of CFU-GM effectively recovered after graft purging was 3.96 +/- 2.09%. All patients engrafted well and their peripheral blood cell recoveries were correlated with graft CFU-GM content evaluated before purging but not after purging or after freezing. In multivariate analysis, this parameter remained the only factor predicting hematopoietic recovery among other patient variables such as sex, age, pathology, disease status, previous chemotherapies or TBI in conditioning regimens. In a subgroup of 39 patients with lymphoid malignancies compared with 25 patients autografted for non-Hodgkin's lymphomas with unpurged marrows, the delay in days (medians) was similar for leukocytes1 x 10(9)/l (19 vs 17 days) and for neutrophils0.5 x 10(9)/l (18 vs 17 days) while it was longer for platelets50 x 10(9)/l (34 vs 128 days).(ABSTRACT TRUNCATED AT 250 WORDS)

In an attempt to improve in vitro pharmacological purging of autologous grafts, the ability of doxorubicin (DOX), alone and in combination with mafosfamide (AZ), to eliminate tumor cells from human bone marrow was assessed. HL60 and Raji cells were mixed with a 20-fold excess of normal marrow cells and were incubated either with DOX (0.4-3.2 micrograms/ml) for 1 h or AZ (20-140 micrograms/ml) for 30 min or both drugs sequentially. Cytotoxicity was evaluated on tumor cells and GM-CFU by clonogenic assays and on earlier hemopoietic progenitors by liquid long-term marrow cultures (LTMC) for 5 weeks. DOX at 3.2 micrograms/ml and AZ at 140 micrograms/ml spared 1.08 and 1.23% of GM-CFU respectively, and yielded similar tumor cell log-kills for HL60 cells (3.04 and 2.95) and Raji cells (3.24 and 3.40). With the combination of AZ and DOX, the best therapeutic index was observed when the cells were incubated with AZ prior to DOX. Under these conditions, AZ at 80 micrograms/ml together with DOX at 1.6 micrograms/ml significantly increased log-kill values for HL60 cells to 3.96 by a synergistic effect and for Raji cells to 3.85 by an additive effect. In LTMC, GM-CFU recovery after treatment with AZ alone and with the combination of AZ and DOX was 59.9 and 20.0%, respectively, while it was 7.9 and 2.9% at culture initiation. These results suggest that the purging efficiency of DOX is comparable to that of AZ and may be enhanced by combination with AZ.

Marrow cells from 36 patients with myelodysplastic syndromes (MDS) (13 refractory anemia [RA], 14 refractory anemia with excess of blasts [RAEB], 9 RAEB in transformation [RAEB-T]) were evaluated for their in vitro proliferative and differentiative responsiveness to recombinant human granulocyte colony-stimulating factor (G-CSF) or granulocyte-monocyte CSF (GM-CSF). GM-CSF exerted a stronger proliferative stimulus than G-CSF for marrow myeloid clonal growth (CFU-GM) in these patients (44 v 12 colonies per 10(5) nonadherent buoyant bone marrow cells [NAB], respectively, P less than .025). GM-CSF stimulated increased CFU-GM growth in the 16 patients with abnormal marrow cytogenetics in comparison with the 20 patients who had normal cytogenetics (52 and 30 colonies per 10(5) NAB, respectively, P less than .05), whereas no such difference could be demonstrated with G-CSF (11 and 16 colonies per 10(5) NAB, respectively). In contrast, granulocytic differentiation of marrow cells was induced in liquid culture by G-CSF in 15 of 32 (47% patients), while GM-CSF did so in only 4 of 18 (22%) patients (P less than .025) including, for RAEB/RAEB-T patients: 9 of 18 versus 0 of 9, respectively (P less than .025). For MDS patients with normal cytogenetics, G-CSF- and GM-CSF-induced marrow cell granulocytic differentiation in 12 of 18 (67%) versus 3 of 11 (27%), respectively (P less than .025), contrasted with granulocytic induction in only 3 of 14 (21%) and 1 of 7 (14%) patients with abnormal cytogenetics, respectively. We conclude that G-CSF has greater granulocytic differentiative and less proliferative activity for MDS marrow cells than GM-CSF in vitro, particularly for RAEB/RAEB-T patients and those with normal cytogenetics.

Activity coefficients for cyclohexanol in diluted isooctane solutions at 25°C and 45°C are obtained from vapour pressure measurements, xu = 10−3 to 5.10−2 (xu mole fraction of cyclohexanol) ; enthalpies of mixing for the same composition range are obtained at 25°C. The results are interpreted in terms of the model of ideal association where open dimer and trimer, open and cyclic other i-mers are considered in a six parameters model : two standard enthalpies for formation of the H-bonds (ΔH2o for the dimer and h for the stepwise formation for other bonds), four equilibrium constants (K2o and K3o for the dimer and trimer formation from the monomer, Kc for the cyclisation of an open i-mer and k for the stepwise formation of an open, or cyclic, i-mer higher than the trimer). The cyclic form of the tetramer is shown to be the predominent one.

Resume Une etude preliminaire de l'isopropylate d'aluminium [(CD3)2CHO]3Al en solution dans CCl4, permet de caracteriser les vibrations γ(CH), δ(CH) et ν(CH) des groupements isopropylate soit libres ou coordines dans les complexes d'autoassociation. L'etude des vibrations ν(CH) et {δ(CH),δ(OH)} dans la co-adsorption de l'isopropanol(D6) avec la pyridine(D5) (base de Lewis) ou le pentachlorure d'antimoine (acide de Lewis) ou le perfluorotertiobutanol, qui s'adsorbe dissociativement, permet de mettre en evidence les differentes especes, dissociees ou coordinees, formees par l'adsorption de l'isopropanol(D6) sur des couples de sites (O,Al). La dissociation de l'isopropanol(D6) se fait sur des sites O tres basiques. La coordination se fait a la fois par interaction de Lewis et par pont hydrogene ; deux especes coordinees sont mises en evidence sur des couples de sites (O base forte, Al acide faible) et (O base faible, Al acide fort) ; l'energie d'interaction est evaluee a − 40 kcal mol−1. L'adsorption du perfluorotertiobutanol cree des groupements hydroxyle de surface tres acides : l'energie du pont hydrogene qu'ils forment avec l'isopropanol(D6) physisorbe est evaluee a − 12 kcal mol−1.

The Raman intensity of the ν(CH) band of 1,5-hexadiyne has been determined for different states of association; autoassociation of 1,5-hexadiyne has been comparatively studied by Raman and infrared spectroscopy. The integrated Raman intensity of the ν(CH) band is independant of the state of association within the error limits (⋍10%).

Resume Dans la formation du complexe X-H…O(H)CH(CD 3 ) 2 , en solution dans le tetrachlorure de carbone, d'un donneur de proton XH avec l'isopropanol(D 6 ) on observe pour l'isopropanol(D 6 ) une augmentation de ν (CH) de l'ordre de 15 a 45 cm −1 suivant le pouvoir donneur de proton de XH et une diminution de ν (OH) de l'ordre de 13 a 21 cm −1 ; l'anharmonicite de ν(OH) n'est pas affectee. Quand le groupement CH est plus eloigne du groupement hydroxyle [complexe (CF 3 ) 3 COH…..O(H)CD 2 CD 2 H] l'augmentation de ν (CH) nest que de 3 cm −1 . Le nombre d'ondes de la vibration ν(OH) du groupement hydroxyle libre dans le dimere lineaire d'autoassociation de l'isopropanol(D 6 ) est inferieur de 5 cm −1 a la valeur observee pour le monomere. L'intensite de la bande ν(CH) diminue generalement dans la complexation, celle de la bande ν(OH) est peu modifiee, ou exaltee quand le donneur de proton est le perfluorotertiobutanol.

Resume L'influence de la complexation sur la vibration ν(CH) a ete etudiee dans les complexes R2CHOH…Y (R = CF3; CD3 ; Y = base) ; elle depend de la conformation de la molecule d'alcool. Quand le groupement CH est transpar rapport au groupement OH, les abaissements de ν (CH) dans la complexation sont proportionnels a ceux de ν (OH) ; pour les formes gauches, la relation entre'les abaissements de ν (CH) et ceux de ν (OH) depend de R et pour R = CF3 elle depend aussi de la basicite de Y. On met ainsi en evidence le caractere directionnel de la delocalisation electronique dans la liaison hydrogene. I1 n'y a pas d'influence notable de la complexation sur les intensityes des bandes νCH). Une liaison C-H…Y a ete envisagee pour rendre compte de la solvatation des complexes (CF3)2CHOH…Y par les bases Y.

From study of the ν(CC) Raman band of 4-octyne (a proton acceptor) is is shown that, whenever the solvent is respectively a poor or a good proton donor, the formation of the hydrogen bond increases or decreases the integrated intensity of the band comparatively to pure liquid. From study of the ν(CC) Raman band of 1-octyne (an electron acceptor) it appears two groups of electron donor solvents: (i) solvents whose effect is compatible with solvent — cage model, (ii) solvents for which the intensity of the ν(CC) band depends of ionization potential, the result suggests a charge-transfer model.

Resume L'etude des complexes en solution dans le tetrachlorure de carbone met en evidence les interactions A ← O(H)CH(CD3)2 et A ← [(CD3)2CHOH]2, ou A designe un acide de Lewis : SbCl5, AlCl3, AlBr3, SnCl4, BF3, Eu(fod)3, Icl, I2 et S02. Dans la coordination les frequences des vibrations ν(OH) et ν(CO) sont abaissees et les intensites augmentees ; la frequence de la vibration ν(CH) est augmentee et l'intensite abaissee ; la bande ν(CD3) apparait sous forme de doublet ; les frequences des vibrations γ(CH) et {δ(OH),δ(OH)} sont peu affectees. Une relation affine entre l'enthalpie de complexation avec les acides de Bronsted ou de Lewis et les deplacements Δ ν (CH) a ete etablie.

Resume Les coefficients molaires d'extinction des vibrateurs ν(OH) spectroscopiquement discernables dans les complexes d'autoassociation du cyclohexanol en solution dans 1'isooctane, a 25°C et a 45°C, sont obtenus a partir d'un modele thermodynamique de solution associee. Les coefficients molaires d'extinction pour le monomere et pour les groupements hydroxyles terminaux des especes ouvertes ont des valeurs tres voisines (57 M−1 cm−1 a 25°C). Pour les groupements hydroxyles non terminaux les coefficients molaires d'extinction ont pour valeurs a 25°C, en M−1 cm−1 : 93 pour le dimere ouvert ( ν = 3515 cm−1), 90 pour le trimere ouvert ( ν = 3440 cm−1), 126 pour les autres i-meres ( ν = 3340 cm−1).

An in vitro study of platelet concentrates storage for 5 days was performed in PVC bags. Modification of the original three-day containers were introduced by thickness reduction. The results at fifth day were comparable to those at third day in standard plastic bags. During storage, variations of platelet counts were very slight with a low LDH release. PH was stable with a good maintenance of phase microscope platelet morphology. PCO2 and PO2 measurements showed a satisfactory gas permeability which could explain a limited lactate production. If in vivo studies of transfusion recovery confirm these data, platelet concentrates storage could be extended up to 5 days by such modifications of standard three-day PVC bags.

Cutaneous involvement in the dysproteinemias are of unusual occurrence. The authors report a case of Waldenstrom disease evolving to a biclonal dysglobulinemia with cutaneous involvement. The different possibilities of association between cutaneous manifestations and dysproteinemias are reviewed.

Cutaneous pigmentation, lingual leukoplasia and dystrophic changes of nails are present in the two cases. The other clinical manifestations are dental alterations, epiphora, loss of dermal ridges of the pulp with hyperhidrosis, atrophic skin of the dorsum of the hands. Dysphagia and bone marrow hypoplasia are present in one case. The proband (case 1) has normal values for the following: hemoglobin electrophoresis, pyruvate kinase, marrow and blood chromosome analysis. Biopsy of pigmented skin showed an atrophic epidermis with orthokeratotic-hyperkeratosis; in the higher dermis there were several melanophores. Multiple layers of vasal lamina are seen under electron microscopy. The parents and the two daughters are free of clinical or hematologic manifestations. The mother and her two affected sons have A1-BW 27 HLA haplotype. X-linked transmission is discussed.

A parasitological and immuno-hematological study was undertaken simultaneously in fifty South-East asian refugees at the time of their arrival in France. --in this series the frequency of individuals having a P2 erythrocyte phenotype is 80%. --54 % of these immigrants were found to be carriers of Clonorchis sinensis, a parasite rarely found in Europe. --in 40,7 % of these subjects infested by Clonorchis sinensis, the following properties were disclosed concerning the P1 allo-antibody: slow-P1 red cell agglutination at 22 degrees C, no hemolysis of P1 red cells in vitro, IgM antibody, in weak titers. The immuno-hematological study of the immuno-serums with respect to distomian antigens coupled with adsorption-elution using P1+++ red cells shows a close immunological relationship between the antibody of parasite origin and the anti-P1 allo-antibody.