Bulgarian Academy of Sciences

About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Coupling constant & Catalysis. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences，簡稱：BAS & Balgarska Akademiya na Naukite.

Catalytic properties and potential applications of Bacillus lipases

Abstract: Up to date more than 70 lipases from the Bacillus and Geobacillus genera have been isolated, but for most of them only basic biochemical properties have been reported. In general, Bacillus lipases are easily produced and display high tolerance toward organic solvents, proving them useful in the synthesis of esters for food industry, cosmetics and biodiesel production. Many lipases preserve their activity at extreme temperatures and pH, and in the presence of surfactants, hydrogen peroxide, sodium hypochlorite, and therefore they can be applied in laundry formulations. Bacillus lipases display diverse selectivity to the chain length of the acid, and few enzymes show positional specificity. Several enzymes can be applied in the production of enantiopure compounds for the pharmaceutical industry due to their remarkable enantioselectivity. The immobilization experiments with Bacillus lipases, though a limited number, illustrate the vast possibilities for optimization of the properties of the biocatalysts for a particular application. The paper summarizes available experimental data on Bacillus and Geobacillus lipases and identifies areas for further research.

Activity of wrist muscles elicited during imposed or voluntary movements about the elbow joint.

Abstract: To examine the coordination of muscles during multijoint movement, we compared the response of wrist muscles to perturbations about the elbow joint with their activation during a volitional elbow movement. The purpose was to test the following two predictions: (a) Responses can occur in muscles not stretched by the perturbation, as has been reported for other multijoint systems; and (b) the motor pattern in response to a perturbation mimics an opposing volitional motor pattern across the two joints. We recorded the electromyographic (EMG) activity of elbow and wrist muscles as well as the flexion/extension motions at the elbow and wrist joints during individual trials that either involved a response to a torque perturbation that extended the elbow or required volitional elbow flexion. The results of this study confirmed that responses were elicited in the nonstretched wrist muscles when the elbow joint was perturbed. The same motor sequence of elbow and wrist flexors was present for both the voli...

MCM-41 supported PdNi catalysts for dry reforming of methane

Abstract: A series of bimetallic PdNi catalysts supported on mesoporous MCM-41 with different Ni content (Ni/Si ratio of 0.2–0.4) was synthesized. The effect of Pd addition to Ni-containing catalysts as well as the effect of the Ni content on the surface and catalytic properties of the catalysts was studied. The samples were characterized using various techniques, such as energy-dispersive X-ray spectroscopy, N2 adsorption–desorption isotherms, X-ray diffraction, thermogravimetric and differential analyses, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy and temperature-programmed reduction. Reforming of methane with carbon dioxide was used as a test reaction. The results indicated that the addition of a small amount of Pd (0.5%) to Ni-containing catalysts leads to formation of small nano-sized, easy reducible NiO particles. Agglomeration of NiO as well as of metallic nickel phase over PdNi samples increased with increasing the Ni content. Formation of filamentous carbon over surface of spent monometallic Ni and bimetallic PdNi catalyst was observed. In spite of filamentous carbon deposition, the catalytic activity and stability of bimetallic PdNi catalysts are higher than those of monometallic Ni one. Within bimetallic system, the PdNi catalyst with Ni/Si ratio of 0.3 revealed the best performance and stability caused by presence of small nickel particles well dispersed on the catalyst surface.