A multi-sample automatic system for in situ electrochemical X-ray diffraction synchrotron measurements.

An automatic system that allows continuous in situ electrochemical X-ray diffraction measurements has been developed and implemented at the MS-X04SA beamline at the Swiss Light Source. The system consists of an automatic sample changer, improved ;coffee bag' electrochemical cells, and simple control software. The sample changer can sequentially move up to 32 electrochemical cells into the beam. For each cell an independent electrochemical program is possible. The MYTHEN microstrip detector at the beamline enables parallel detection of diffracted X-ray beams and, thus, fast data acquisition, along with a high 2theta resolution. In this communication the set-up is presented on two typical examples from the field of lithium-ion batteries, (i) structural changes in a layered LiCoO(2) positive electrode upon battery charging and (ii) the effect of co-intercalation of ionic liquids into the graphite negative electrode.

Demonstrating oxygen loss and associated structural reorganization in the lithium battery cathode Li[Ni0.2Li0.2Mn0.6]O2.

The cathode in rechargeable lithium-ion batteries operates by conventional intercalation; Li+ is extracted from LiCoO2 on charging accompanied by oxidation of Co3+ to Co4+; the process is reversed on discharge. In contrast, Li+ may be extracted from Mn4+-based solids, e.g., Li2MnO3, without oxidation of Mn4+. A mechanism involving simultaneous Li and O removal is often proposed. Here, we demonstrate directly, by in situ differential electrochemical mass spectrometry (DEMS), that O2 is evolved from such Mn4+ -containing compounds, Li[Ni(0.2)Li(0.2)Mn(0.6)]O2, on charging and using powder neutron diffraction show that O loss from the surface is accompanied by diffusion of transition metal ions from surface to bulk where they occupy vacancies created by Li removal. The composition of the compound moves toward MO(2). Understanding such unconventional Li extraction is important because Li-Mn-Ni-O compounds, irrespective of whether they contain Co, can, after O loss, store 200 mAhg(-1) of charge compared with 140 mAhg(-1) for LiCoO(2).

Rechargeable LI2O2 electrode for lithium batteries.

Rechargeable lithium batteries represent one of the most important developments in energy storage for 100 years, with the potential to address the key problem of global warming. However, their ability to store energy is limited by the quantity of lithium that may be removed from and reinserted into the positive intercalation electrode, Li(x)CoO(2), 0.5 < x < 1 (corresponding to 140 mA.h g(-1) of charge storage). Abandoning the intercalation electrode and allowing Li to react directly with O(2) from the air at a porous electrode increases the theoretical charge storage by a remarkable 5-10 times! Here we demonstrate two essential prerequisites for the successful operation of a rechargeable Li/O(2) battery; that the Li(2)O(2) formed on discharging such an O(2) electrode is decomposed to Li and O(2) on charging (shown here by in situ mass spectrometry), with or without a catalyst, and that charge/discharge cycling is sustainable for many cycles.

Characterization of brain natriuretic peptide in long-term follow-up of pulmonary arterial hypertension.

STUDY OBJECTIVES: Pulmonary arterial hypertension (PAH) leads to substantial morbidity and mortality. Noninvasive parameters in the follow-up assessment of PAH could be helpful in clinical decision making. The brain natriuretic peptide (BNP) has been shown to correlate with the functional status and prognosis of these patients and could be a valuable parameter in this respect. The aim of our study was to investigate whether BNP levels could reflect clinical and hemodynamic changes, including the response to therapy during long-term follow-up in patients with PAH. STUDY DESIGN: We measured pulmonary hemodynamics, functional parameters including the 6-min walk distance (6MWD), and plasma BNP levels at baseline and after a mean (+/- SEM) follow-up period of 12.6 +/- 1.5 months in patients with PAH. RESULTS: In group A (n = 18), with decreasing BNP levels mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) decreased (PAP, 60.89 +/- 3.44 to 53.47 +/- 3.24 mm Hg; PVR, 1,207.47 +/- 111.75 to 942.35 +/- 103.15 dyne.s.cm(-5); p < 0.01) and 6MWD increased (408.24 +/- 29.57 to 470 +/- 25.54 m; p < 0.01). In group B (n = 12), with increasing BNP levels mean PAP and PVR increased (PAP, 52 +/- 3.31 to 60.17 +/- 5.03 mm Hg; PVR, 946.13 +/- 115.35 to 1,236.6 +/- 180.23 dyne . s . cm(-5); p < 0.01) and mean 6MWD decreased from 463.64 +/- 27.77 to 367.27 +/- 38.87 m (p < 0.05). Comparing groups revealed statistically significant differences regarding changes in PAP (group A, -11.58 +/- 3.57%; group B, +13.29 +/- 5.44%; p = 0.001) and PVR (group A, -19.21 +/- 5.87%, group B, +30.35 +/- 7.72%; p < 0.001). Correlations existed between the changes in BNP levels and pulmonary hemodynamics. CONCLUSION: We concluded that BNP levels parallel changes in pulmonary hemodynamics and functional parameters, including the 6MWD, in PAH patients. Consequently, we suggest BNP as a parameter for the follow-up assessment of PAH patients.

A new type of nano-sized silicon/carbon composite electrode for reversible lithium insertion.

A new type of nano-sized silicon/carbon composite was developed. It shows superior electrochemical cycling properties as negative electrode material for possible use in lithium-ion batteries with respect to high reversible and low irreversible capacity, and low fading.

Stable cycling of graphite in an ionic liquid based electrolyte.

1-Ethyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide (EMI-TFSI) has been shown to reversibly permit lithium intercalation into standard graphite when vinylene carbonate is used in small amounts as an additive.

Brain natriuretic peptide and exercise capacity in lung fibrosis and pulmonary hypertension.

Pulmonary hypertension (PH) can develop in lung fibrosis, and contributes to increased morbidity and mortality. Noninvasive parameters in the evaluation of PH in lung disease could aid in the management of these subjects. In this study, we aimed to characterize the role of brain natriuretic peptide (BNP) and the six-minute walk distance (6-MWD) in the assessment of pulmonary hypertension (PH) in subjects with lung fibrosis. Subjects with lung fibrosis and elevated BNP levels (n = 20) had significantly more severe PH during right heart catheterization than those with lung fibrosis, and normal BNP levels (mean pulmonary arterial pressure (40.85 +/- 3.2 mm Hg vs. 23.42+/-1.44 mm Hg, respectively) (n = 19) (p < 0.001). Significant correlations between lung volumes and BNP concentrations were not observed. A weak correlation existed between capillary pO(2) and 6-MWD (r = 0.42; p < 0.001). The presence of moderate-severe PH was associated with significant reduction of the 6-MWD. BNP concentrations predicted moderate-severe PH with 100% sensitivity and high specificity (89%). We conclude that BNP is an excellent marker for the presence of PH in patients with lung fibrosis. In addition, our data suggest that PH contributes significantly to exercise limitation in patients with severe lung fibrosis, raising the possibility that treatment of PH may be beneficial in these patients.

Clinical significance of brain natriuretic peptide in primary pulmonary hypertension.

OBJECTIVES: The aim of this study was to investigate the potential role of brain natriuretic peptide (BNP) levels in the assessment of functional status and right heart performance in primary pulmonary hypertension (PPH). BACKGROUND: Primary pulmonary hypertension is a progressive disease leading to right heart failure and death. Right heart catheterization and maximal or submaximal exercise tests are employed to assess the course of the disease and the effect of therapeutic interventions. Additional noninvasive and reproducible parameters would be helpful to assess the status of patients with PPH. The natriuretic peptide system is up-regulated in PPH patients. Brain natriuretic peptide (BNP) is produced from the cardiac ventricles and elevated in PPH. The aim of our study was to evaluate the clinical significance of BNP in PPH patients. METHODS: Correlation analysis was performed for plasma BNP levels of 28 PPH patients and World Health Organization (WHO) functional class (WHO-class), distance walked in 6 min, peak oxygen uptake (peak Vo(2)), and oxygen pulse during spiroergometry and various hemodynamic parameters, including pulmonary vascular resistance (PVR), pulmonary artery pressure (PAP), right atrial pressure (RAP), and cardiac index. RESULTS: The BNP levels were inversely correlated with the 6-min walk (r = -0.70; p < 0.001) and peak Vo(2) (r = -0.61; p < 0.01), and positive correlation was observed with WHO-class (r = 0.79; p < 0.001). Moreover, BNP levels were also correlated to PVR (r = 0.61; p < 0.01), PAP (r = 0.48; p < 0.05), and RAP (r = 0.78; p < 0.01), and were inversely related to cardiac index (r = -0.48; p < 0.05). CONCLUSIONS: Our data suggest that plasma BNP levels are closely related to the functional impairment of PPH patients and parallel the extent of pulmonary hemodynamic changes and right heart failure. Serial measurements of plasma BNP concentrations may help improve the management of PPH patients.