Compensation effect and volcano curve in toluene hydrogenation catalyzed by transition metal sulfides.

Within the framework of volcano curves, a kinetic study of toluene hydrogenation catalyzed by transition metal sulfides highlights the variation of the apparent kinetic parameters as a function of the ab initio sulfur-metal bond energy descriptor and sulfo-reductive reaction conditions.

Nature, structure and strength of the acidic sites of amorphous silica alumina: an IR and NMR study.

IR spectroscopy of probe molecules (pyridine, 2,6-dimethylpyridine, and CO) as well as high-resolution solid state NMR and especially double-resonance experiments give a new insight into the acidic sites of amorphous silica alumina (ASA). ASA samples are heterogeneous compounds that contain a silica alumina mixed phase as well as aluminum clusters and pure silica zones. The distribution of various forms depends both on the preparation method and on the Si/Al ratio. Formation of mixed phase leads to the creation of acidic hydroxyl groups of various strength, up to that present in dealuminated HY zeolite. Detailed spectroscopic analyses show that these acidic OH groups correspond to the silanol groups located in close vicinity to an Al atom in tetrahedral environment. The strength of the acidity of the OH species of ASA could be modified both by the location of the vicinal Al atom on the surface or in the bulk and by the number of aluminum atoms in the vicinity of silanol group. Cogelification of high silica-containing ASA appears as the best mean to prepare homogeneous amorphous aluminosilicate, which exhibits the strongest Brønsted acidity.

Information obtained from tussigrams and the possibilities of their application in medical practice.

The physiology of cough was studied using 2008 voluntary coughs. The tussiexpirograms verify that in a cough-series there are "double-flow" phases. The tussitachogram enables a more precise observation, for example, one can recognise five flow phases within one single cough. It proves, furthermore, that in the first five coughs the speed of airflow is always higher in the intermediate deceleration than in the acceleration phase. On the tussiphonogram one can differentiate seven phonetic phases. The simultaneously recorded tussigrams and tussiphonograms allow identification of two sounds, two intervals and noises. There are at least two possibilities for use of these data in clinical practice, 1) the measurement of the volume during the first second on the tussiexpirogram is a suitable control for the forced expiratory volume in one second (FEV1), 2) analysis of the voluntary prolongation of the intermediate deceleration during respiratory physiotherapy.

Graphometric analysis of cough tachogram.

The tachogram shows that the flow of cough is neither continuous nor steady. Within a cough, 5 different phases can be differentiated: 1) acceleration, 2) initial fast decleration, 3) intermediary decleration, 4) terminal fast decleration, and 5) the flow-pause. Only in the course of phases 1) and 3) is the air flowing out from the lungs. In cough series the peak-flows of subsequent coughs are growing smaller and smaller. This decrease follows the form of an isosceles hyperbola. A cough can be short or elongated. From the flow-phases the 1-st, 2-nd and 4-th ones are of fairly stable duration. The wide deviation of the intermediary deceleration shows that this phase makes it possible to elongate voluntarily the cough.