2-step lignin-first catalytic fractionation with bifunctional Pd/ß-zeolite catalyst in a flow-through reactor.

This work demonstrates an additive and hydrogen-free 2-step lignin-first fractionation in flow-through. First, solvolytic delignification renders lignin liquors with its native chemical structure largely intact; and second, ß-zeolite catalytic depolymerization of these liquors leads to similar monomer yields as the corresponding 1-step fractionation process. Higher delignification temperatures lead to slightly lower ß-O-4 content in the solvated lignin, but does not affect significantly the monomer yield, so a higher temperature was overall preferred as it promotes faster delignification. Deposition of Pd on ß-zeolite resulted in a bifunctional hydrogenation/dehydration catalyst, tested during the catalytic depolymerization of solvated lignin with and without hydrogen addition. Pd/ß-zeolite displays synergistic effects (compared to the Pd/γ-Al2O3 and ß-zeolite tested individually and as a mixed bed), resulting in higher monomer yield. This is likely caused by increased acidity and the proximity between the metallic and acid active sites. Furthermore, different ß-zeolite with varying SAR and textural properties were studied to shed light onto the effect of acidity and porosity in the stabilization of lignin monomers. While some of the catalysts showed stable performance, characterization of the spent catalyst reveals Al leaching (causing acidity loss and changes in textural properties), and some degree of coking and Pd sintering.

[The hemodynamic component of an electrocardiogram]. / Gemodinamicheskii komponent élektrokardiogrammy.

Electric and dynamic properties of intracardiac blood are not taken into account considering questions of surface electrocardiogram genesis. Therefore assumptions of the lack of electric processes reflecting on the body surface are made. However in 7 male patients (mean age 38 +/- 2) suffering from aortic insufficiency by means of signal-averaged body surface mapping in diastole low amplitude negative potentials in regard to central terminal of Wilson are discovered. The potentials localize in the left anterior thoracic region, the amplitude of minimum varies in relation to the patient's clinical status and equals to hundreds of microvolts. As the phenomenon is sufficiently remote from the moment of the possible U wave appearance and precedes for tens of milliseconds to the beginning of atrial depolarization we suggested that it is caused exclusively by hemodynamic factors. For the experimental proof of the hypothesis the potentials difference between parts of aqueous 0.9% sodium chloride solution on the moment of flow generation within it are detected by means of differential amplifier with input impedance of 1 G omega to constant current. The registered signal has the form of a decremental harmonic oscillation. The mathematical model of the process in the form of differential equation connecting the volume density of charges in the electrolyte, its viscosity and the acceleration of the flow within the electrolyte has been constructed. Thus, the intracavitary blood as an electrolyte with different ions movability which moves with acceleration possesses the electrogenic properties and their contribution must be taken into account in the consideration of mechanisms of the surface electrocardiogram generation.

[Automated rapid examination of the cerebral ventricular system by the method of uni-dimensional echoencephalography]. / Avtomatizirovannoe ékspress-issledovanie zheludochkovoi sistemy golovnogo mozga metodom odnomernoi ékhoéntsefalografii.

To examine patients suffering from diseases of the nervous system, use was made of a programmed apparatus complex that ensures an automated analysis of echosignals from different parts of the third and lateral ventricles. The complex is assembled on the basis of microcomputer. The method suggested has been demonstrated to be informative in the diagnosis of hydrocephalus and sizable injuries to the brain during mass screenings.