Thermal evolution of the layered oxide Li2/3Co2/3Mn1/3O2, showing a T#2 stacking and prepared by a Na/Li ion exchange in P2-Na2/3Co2/3Mn1/3O2, was investigated by thermal analyses and X-ray ...diffraction. A thermal expansion of the T#2 orthorhombic unit cell is observed from 25 to 350 °C; from 350 °C the T#2 stacking is destabilized to the benefit of an O6-type stacking obtained from the former through slab gliding. The T#2 to O6 phase transformation is allowed to occur from a stacking with larger interlayer distances and the lithium ions in tetrahedral sites to a stacking with smaller interlayer distances and the lithium ions in octahedral sites. This phase transition from T#2 to O6 is reversible, even though its kinetic can be very slow: the thermal treatment of the T#2-type Li2/3Co2/3Mn1/3O2 phase at 450 °C with a quenching in air has shown to stabilize the O6HT-Li2/3Co2/3Mn1/3O2 phase. At temperatures higher than 450 °C, the layered oxide Li2/3Co2/3Mn1/3O2 is gradually decomposed into Li2MnO3 and Co3O4. First electrochemical tests performed in lithium batteries have revealed that O6HT-Li2/3Co2/3Mn1/3O2 delivers as positive electrode material a high reversible capacity of ∼230 mAh·g–1 over two voltage domains around 3 and 4 V vs Li+/Li.
Background: A study was undertaken of deaths with an underlying or associated cause of chronic obstructive pulmonary disease (COPD), and trends in COPD mortality from 1979 to 2002 in France were ...analysed. Methods: Data were obtained from the Centre of Epidemiology on the Medical Causes of Death (CépiDc) for individuals aged 45 years and over. Owing to implementation of ICD-10 in 2000 for recording causes of death, two separate periods were analysed (1979–99 and 2000–2). Results: In 2000–2, COPD was the underlying cause of 1.4% of deaths (deaths from COPD) and was mentioned on the death certificate in 3.0% (deaths with COPD). The other main underlying causes in these cases were cardiovascular diseases (32.0%) and cancers (24.5%). In 1979–99, age standardised rates of death with COPD remained stable in men (−0.01%/year) and increased in women (+1.7%/year). The mean annual rates of death with COPD per 100 000 were 84 for men and 19 for women in 2000–2. Conclusion: Multiple cause analysis improved the estimate of COPD related mortality. In 1979–99, COPD related mortality rates in France were stable in men but increased in women. Implementation of ICD-10 in 2000 introduced substantial discontinuities in mortality trends.
To diagnose invasive fungal infections, the detection of (1 → 3)-β-
d
-glucan in serum has shown variable specificity, depending on the targeted population. Several circumstances for false-positive ...results of beta-glucan tests have been identified, among which are severe bacterial infections. In this study, we measured (1 → 3)-β-
d
-glucan by the Fungitell test in the serum of 62 patients (one serum sample tested per patient) for whom invasive fungal infection was not suspected: 19 control subjects and 43 patients with bacteraemia. The test was interpretable for 58 sera: all 19 control subjects had negative beta-glucan test; among the 39 bacteraemic patients, we report 16 false-positive results. For the 22 patients undergoing bacteraemia due to Gram-negative bacilli, we observed 13 false-positive results (59%). Among the 17 patients with bloodstream infection involving Gram-positive cocci, three false-positive tests were recorded, but none in the eight cases of
Streptococcus pneumoniae
bacteraemia. Statistical analysis showed that beta-glucan levels were significantly higher in patients with Gram-negative bacilli bloodstream infection in comparison to those with bacteraemia due to Gram-positive cocci. These results were independent from other previously described causes for false-positive beta-glucan tests. These data might help physicians to interpret positive beta-glucan detection when an invasive fungal infection is suspected, especially for patients with bacterial infections.
Aluminum-based coatings are commonly used in lithium-ion batteries to modify the surface of LiCoO2 particles, to limit cobalt dissolution in the electrolyte at high voltage. It was shown that the ...formation of a LiCo1−xAlxO2 solid solution occurs at the interface between the coating and the core material. In this paper, we investigated the surface properties of LiCo1−xAlxO2 materials by X-ray photoelectron spectroscopy. We explored the surface acid−base properties of these materials by adsorption of gaseous probe molecules (NH3 and SO2) followed by XPS analyses. We showed that the basic character of the LiCo1−xAlxO2 surface strongly decreases when x increases, which makes these materials less reactive than LiCoO2 toward acidic species (such as HF) that are present in LiPF6-based electrolytes. This is a possible explanation for the efficiency of Al-based coatings to protect LiCoO2 against cobalt dissolution in the electrolyte.
Exposure to mould is a potential risk factor for asthma in both adults and children. In adult, the relation between exposure, sensitization and symptoms has been demonstrated in severe asthmatics ...sensitized to Alternaria. For children, exposure to mould in childhood is a risk factor for asthma in both atopic and non-atopic individuals. Exposure or sensitization to moulds are a risk factor for severe asthma and/or exacerbations in children. There appears to be a causal relationship between exposure and asthma. This link seems less significant in adults. However, in adults mould sensitive asthma seems to determine a phenotype of severe asthma associated with more marked obstructive lung disease. Moulds can stimulate either innate or the acquired immunity. They are responsible for a marked Th2 inflammation leading to more severe asthma. Besides the immunological mechanisms, toxic mechanisms can also intervene. It is therefore not correct to reduce the effect of moulds, particularly in respiratory symptoms, to only allergic mechanisms.
The composition and synthesis conditions of the (Li/Na)CoO2 phase with an ordered 1:1 Li/Na stacking alternating with CoO2 slabs were determined from a careful study of the P2-Na∼0.7CoO2−O3-LiCoO2 ...system. An in situ X-ray diffraction (XRD) thermal study emphasizes the metastable character of this phase that can be stabilized only by very fast quenching. Its composition, (Li0.42Na0.37)CoO2, is significantly different from the ideally expected one, (Li0.50Na0.35)CoO2, and its structure, confirmed by Rietveld refinement of the XRD pattern, presents an ideal alternate ordering of lithium, cobalt, and sodium layers within OP4-type oxygen packing. The presence of vacancies in both alkali-ion layers was confirmed by electrochemical intercalation of lithium and sodium. For the first time, a new type of layered oxide exhibiting OPP9-type oxygen packing was evidenced. Between the CoO2 slabs, alkali ions are intercalated in the following order: Liocta−Naprism−Naprism. This material crystallizes in the R3̅m space group with a hex = 2.828 Å and c hex = 46.85 Å cell parameters.
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