In situ X-ray absorption spectroscopy study of Si(1-x)Ge(x)O2 dissolution and germanium aqueous speciation under hydrothermal conditions.

The dissolution of Si(1-x)Ge(x)O(2) solid solutions under hydrothermal conditions was studied by in situ X-ray absorption spectroscopy. Experiments were performed at the Ge K-edge using a high-pressure cell mounted on the FAME beamline of the European Synchrotron Radiation Facility. Spectra in both transmission and fluorescence mode were collected in isobaric conditions (100 and 150 MPa) up to 475 °C. The local atomic structure around the Ge atom was investigated as a function of the temperature and in pure water and sodium hydroxide solutions. In pure water, the solubility of the cristobalite-type Si(0.8)Ge(0.2)O(2) increases with the temperature and the Ge atom is in 4-fold coordination. In a sodium hydroxide aqueous solution, a complex between Ge and Na atoms forms and gives rise to precipitation of sodium germanates. Under these conditions, the Ge content in the solution decreases with increasing temperature. These results show that a sodium hydroxide aqueous solution, usually used for quartz crystal growth, is not suitable for Ge-containing crystals. The dissolution kinetics and phase transformation of the solid solution were studied as a function of the atomic fraction of Ge. Ge-rich solid solutions dissolve and transform to stable phases faster than Ge-poorer composition, giving rise to important variations of the Ge content in solution.

Hydrothermal growth and structural studies of Si(1-x)Ge(x)O2 single crystals.

The substitution of germanium in the α-quartz structure is a method investigated to improve the piezoelectric properties and the thermal stability of α-quartz. Growth of α-quartz type Si(1-x)Ge(x)O(2) single crystals was performed using a temperature gradient hydrothermal method under different experimental conditions (pressure, temperature, nature of the solvent, and the nutrient). To avoid the difference of dissolution kinetics between pure SiO(2) and pure GeO(2), single phases Si(1-x)Ge(x)O(2) solid solutions were prepared and used as nutrients. The influence of the nature (cristobalite-type, glass) and the composition of this nutrient were also studied. Single crystals were grown in aqueous NaOH (0.2-1 M) solutions and in pure water. A wide range of pressures (95-280 MPa) and temperatures (315-505 °C) was investigated. Structures of single crystals with x = 0.07, 0.1, and 0.13 were refined, and it was shown that the structural distortion (i.e., θ and δ) increases with the atomic fraction of Ge in an almost linear way. Thus, the piezoelectric properties of Si(1-x)Ge(x)O(2) solid solution should increase with x, and this material could be a good candidate for technological applications requiring a high piezoelectric coupling factor or high thermal stability.

[Development of a real-time PCR assay for quantitative diagnosis of Toxoplasma gondii after allogeneic bone marrow transplantation]. / Développement d'une technique de PCR quantitative en temps réel dans le diagnostic de la toxoplasmose chez des patients greffés de moelle osseuse.

AIMS OF THE STUDY: A sensitive, rapid and specific diagnostic method is essential for the diagnosis of toxoplasmosis in immunocompromised hosts or in congenital infection. We report the development of a real-time PCR assay for quantitative diagnosis of toxoplasmosis with competitive internal amplification control. This PCR was applied after allogeneic stem cell transplantation to estimate the frequency of reactivation. METHODS AND PATIENTS: Primers and Taqman probe (FAM-BHQ1) were designed to amplify the 529 bp element of T. gondii. The internal amplification control was developed by cloning a fragment of Arabidopsis thaliana DNA flanked by sequences specific for T. gondii 529 bp element. A Taqman probe specific for the competitive internal control was designed and tested (YY-BHQ1). We determined the repeatability and reproducibility of the method. A prospective study was performed on adults who received an allogeneic hematopoietic stem cell transplantation. After transplantation, patients were monitored once per week during the first 100 days; they were then monitored once every 2 weeks until day 180 after transplantation (i.e., day +180). RESULTS: A total of 451 samples from 40 patients were tested. Twenty-five patients had both positive toxoplasmosis serology and an adequate chemoprophylaxis. One sample from one patient was found positive. The rate of reactivation in the population of this study is 4%. CONCLUSION: A monitoring by T. gondii PCR should be realized weekly for patients receiving an allogeneic hematopoietic stem cell transplantation, without an adequate chemoprophylaxis.

The characterization of waste cathode-ray tube glass.

New re-use applications are needed to address the relatively large quantity of waste electronic products generated in the world. Cathode-ray tubes (CRTs) from computer monitors and TV sets are a large component of such waste. The three glass components of CRTs are the funnel, panel and neck, which are produced by various manufacturers and are now collected by asset-recovery centres. In this paper, we characterize waste funnel and panel glass from dismantled cathode-ray tubes with a view to assisting the development of new re-use applications. The heavy metal (lead, barium, and strontium) content of such glass represents an acute risk to the environment. Our results of the chemical composition for different kinds of waste CRT glass including black & white and color CRTs show that CRT glass from different producers have generally similar chemical compositions. In particular, the compositions of funnel and panel black & white CRT glass are similar, but are different to those of panel and funnel color CRT glass. We also measured the following specific properties of each type of CRT glass: density, glass transition temperature, and linear coefficient of thermal expansion. It was found that the coefficients of thermal expansion of CRT glass do not vary with their composition. In contrast, the measured densities and glass transition temperatures do vary with composition. On the basis of our experimental data and data found in the literature, we outline the main properties of several waste CRT glass currently in circulation. The aim of this study was to provide the data required to determine if this kind of waste could be entirely (or partially) re-used and to aid the search for promising methods of treatment.

In vitro susceptibility testing of Candida and Aspergillus spp. to voriconazole and other antifungal agents using Etest: results of a French multicentre study.

Minimum inhibitory concentrations (MICs) of the antifungal agent voriconazole were determined using the Etest and compared with those of amphotericin B, itraconazole and fluconazole using 1986 clinical isolates of Candida spp. Voriconazole MICs were also compared with those of amphotericin B and itraconazole using 391 clinical isolates of Aspergillus spp. Voriconazole was found to have more potent activity and lower MIC values than amphotericin B, itraconazole and fluconazole against C. albicans, C. tropicalis, C. parapsilosis and C. kefyr. Against C. glabrata and C. krusei, voriconazole was more active than either of the other two azole antifungals but had similar activity to amphotericin B. For species of Aspergillus, MIC values of voriconazole were lower than those of amphotericin B and itraconazole against A. fumigatus and A. flavus, and were similar to those of amphotericin B against A. niger. Against A. terreus, MIC values for voriconazole and itraconazole were similar. A. terreus is known to be resistant to amphotericin B, and this was reflected in higher MIC values compared with those of voriconazole and itraconazole. Voriconazole therefore compares very favourably with other antifungal agents against a large number of clinical isolates of Candida and Aspergillus spp.

Ehrlichial DNA amplified from Ixodes ricinus (Acari: Ixodidae) in France.

Granulocytic ehrlichia 16S rDNA was amplified for the 1st time from an Ixodes ricinus (Linne) tick collected in Europe. Sequence analysis of polymerase chain reaction products from the 16S rRNA gene demonstrated the organism from which it originated to be closely related to the agent of human granulocytic ehrlichiosis, an emerging disease that was recently described in the United States; Ehrlichia phagocytophila, the agent of tick-borne fever of ruminants in Europe; and Ehrlichia equi. the agent of the worldwide equine granulocytic ehrlichiosis. These granulocytic ehrlichiae have been associated with Ixodes spp. ticks that may act as vectors. It remains to be determined if each of these granulocytic ehrlichiae, that may constitute variants of the same species, is responsible for a specific disease in animals and in humans.

An in vivo method to assess the photostability of UV filters in a sunscreen.

An in vivo method was developed in order to study the photostability of UV filters in a sunscreen. This method assesses sunscreen photostability in the emulsion after direct interaction with the skin. For this purpose UV filters were recovered from volunteers' forearms by using the stripping technique, then extracted from tapes and quantified by high-performance liquid chromatography (HPLC). The photostability of the filters tested was evaluated by comparing the amount of filters recovered from the strippings of UV-irradiated skin (40 minimal erythema dose, or MED) versus non-irradiated skin. Sequential analysis of several successive tapes reflected the distribution profile of the filters in the stratum corneum. Photochemical change was observed for one filter: it was shown to undergo a photochemical modification with the appearance of an additional HPLC peak. Moreover, UV filters tested displayed a high affinity for the stratum corneum but presented different distribution profiles. This in vivo method takes into account the interaction of the sunscreen agents with the stratum corneum. Furthermore, unlike spectrometric methods usually used for photostability assessment, it gives quantitative data for each individual filter of a finished product by using an HPLC technique.

[Geotrichum capitatum infection in a neutropenic patient. Apropos of a case and review of the literature]. / Infection à Geotrichum capitatum chez un patient neutropénique. A propos d'un cas et revue de la littérature.

INTRODUCTION: Geotrichum capitatum sepsis are rare, occurring exclusively in immunocompromised patients. EXEGESIS: We report the case of a patient with acute leukemia, presenting with chemotherapy-induced neutropenia and hospitalized in an intensive care unit for a severe sepsis. In spite of an antibiotic and antifungal treatment, the patient died of cardiorespiratory failure. Later on, blood cultures proved to be positive for Geotrichum capitatum. CONCLUSION: If fungal infections are common in neutropenic patients, Geotrichum capitatum sepsis remain exceptional. The portal of entry is digestive or respiratory, and the invasion is favored by immunodepression and suppression of the normal microbial flora. Induced lesions can be multiorganic. The treatment is not well established, and the association of either amphotericine B and 5-fluorocytosine or amphotericine B and itraconazole would lead to better results. Nevertheless, the prognosis is still unfavorable, with a mortality rate of approximately 75%.

[Pulmonary pneumocystosis in immunodepression: apropos of 78 consecutive cases seen at the CHRU of Clermont-Ferrand from 1984 to 1993]. / La pneumocystose pulmonaire au carrefour de l'immuno-dépression: à propos de 78 cas consécutifs observés au CHRU de Clermont-Ferrand de 1984 à 1993.

78 consecutive cases of PCP have been analysed: 59 (75.6%) cases were associated with HIV infection and 19 (24.4%) cases were associated with solid tumors and hematologic malignancies at advanced stage of the disease and renal transplantation. It could suggest primary prevention for such patients.

[Malassezia furfur septicemia after bone marrow graft]. / Septicémie à Malassezia furfur au décours d'une greffe de moelle.

BACKGROUND: Systemic Malassezia furfur (Mf) infections are only seen in neonates and immunocompromised patients. CASE REPORT: A 2-year-8-month-old boy was given chemotherapy for mediastinal T cell lymphoma. Meningeal relapse supervened 10 months later, requiring polychemotherapy plus CNS irradiation followed by bone marrow transplantation. Three days after transplantation, fever associated with neutropenia required administration of ceftazidime, amikacin, vancomycin plus acyclovir followed by amphotericin B, cefotaxime plus erythromycin. Blood cultures were negative, but blood swears showed yeasts into polynuclear cells after cytocentrifugation; these yeasts were also present in the central catheter removed after a few days course of amphotericin B, flucytosine plus fluconazole. The patient was then given GM-CSF subcutaneously (5 micrograms/kg/day), followed by progressive correction of aplasia and cure of the Mf infection. CONCLUSION: This is a new case of systemic Mf infection seen in an immunocompromised child receiving parenteral nutrition with lipids.

[A case of post-traumatic Absidia corymbifera fungal endophthalmitis]. / A propos d'un cas d'endophtalmie fongique posttraumatique à Absidia corymbifera.

Exogenous fungal endophthalmitis is a rare postoperative and posttraumatic complication with, often, a dreadful prognosis. We report one case of Absidia corymbifera endophthalmitis after penetrating injury with a retained intraocular vegetable foreign body. We focus on the risk factors for the development of fungal endophthalmitis (vegetable foreign body, corticotherapy) and the importance of ocular fluid samples for stain and appropriate culture. In this case, the treatment associating contaminated tissue extraction and systemic and intravitreal administration of antifungal agents was efficient.

[Distomatosis: diagnosis and treatment]. / Distomatoses: diagnostic et traitement.

Distomatosis caused by Fasciola hepatica is fairly common in France. It is due to the ingestion of contaminated watercress or wild dandelions. Fever is frequent. Jaundice and liver pain are inconstant. The disease is often revealed by an isolated eosinophilia. Ultrasonography and/or computerized tomography are useful to evaluate the hepatic lesions. The diagnosis is confirmed by the finding of eggs in the stools or by serological tests. Numerous other flukes may infect people living overseas and particularly in South-East Asia. Clonorchis sinensis and other Opisthorchidae are responsible for distomatosis of the liver and digestive tract. Several types of intestinal distomatosis may also be acquired. Paragonimiasis (a pulmonary fluke) is particularly frequent in that part of the world. The diagnosis rests on the finding of eggs in the stools (digestive tract distomatosis) or in the airways (paragonimiasis) or on serological tests. The prognosis has been improved by treatment with praziquantel, a drug which in most cases stops the development of the disease within a few days.

[Osteolytic bone lesion: vertebral alveolar echinococcosis in a patient with splenectomy]. / Lésion ostéolytique chez une patiente splénectomisée : à propos d'un cas d'échinococcose alvéolaire vertébrale.

INTRODUCTION: Osteolytic lesions are not always related to malignancies. CASE REPORT: We report an 82-year-old woman suffering from subcostal pain. The patient underwent a splenectomy 40 years previously. CT-scan and MRI highlighted a calcified hepatic lesion associated with an osteolytic lesion of the L5 vertebra. Osteolytic and hepatic lesions were attributed to an alveolar echinococcosis based on positive serological assays. CONCLUSION: To our knowledge, this is the first report of an alveolar echinococcosis in a patient with splenectomy and secondary lesions. We suggest that the splenectomy could have promoted the parasite spreading to vertebra.

Three cases of cutaneous mucormycosis with Lichtheimia spp. (ex Absidia/Mycocladus) in ICU. Possible cross-transmission in an intensive care unit between 2 cases.

Mucormycoses are rare but emerging diseases with poor prognosis caused by ubiquitous fungi from the environment. In November 2008, our teaching hospital experienced three cutaneous mucormycosis due to Lichtheimia spp. (ex Absidia/Mycocladus) in the intensive care and orthopaedic units. Environmental and epidemiological investigations suggested a possible cross-transmission of L. ramosa between two patients in intensive care. This is the first report of possible person-to-person transmission of mucormycosis species. These cases show the ineffectiveness of hydro-alcoholic solutions against spores and underline the need to respect standard precautions to prevent fungi dissemination.