Maximum static inspiratory and expiratory pressures with different lung volumes

Background  

Maximum pressures developed by the respiratory muscles can indicate the health of the respiratory system, help to determine maximum respiratory flow rates, and contribute to respiratory power development. Past measurements of maximum pressures have been found to be inadequate for inclusion in some exercise models involving respiration.     

An Alternative Biotechnological Tool for Magnesite Enrichment: Lactic Acid Bacteria Isolated from Soil

Abstract

Calcium carbonate (CaCO₃) is found in different polymorph structures such as aragonite, vaterite, and calcite. The most common and stable form of CaCO₃, calcite, which is abundant in sedimentary rocks as magnesite ore. Magnesite has application areas in many industrial fields including paper, pharmaceutical and refractory materials. Magnesite is theoretically formulated MgCO₃, but contains many impurities (silicium, iron, and also calcite), that limits its usability and applicability. In this research, we aimed to investigate the decalcification possibility of the raw magnesite material through application of Enterococcus feacelis (EF) with CaCO₃ dissolution ability. The exact mechanism of CaCO₃ dissolution was investigated by carbonic anhydrase enzyme assay and HPLC analysis of organic acids produced by EF. Consequently, EF reduced the amount of CaCO₃ from 2.94% to 0.49% which means a reduction (≈83.33%) in the rate of CaCO₃ percentage. As a result of the experiments, it was observed that different organic acids produced by bacteria reacted with CaCO₃ and removed the lime of magnesite ore. The bacteria used in the study did not show any pathogenic properties in rats, thus, it can be used safely for the industrial applications.     

Synthesis of Imidazole-2,3-dihydrothiazole Compounds as VEGFR-2 Inhibitors and Their Support with in Silico Studies

In this study, 12 novel 2-((1-(4-(1H-imidazol-1-yl)phenyl)ethylidene)hydrazineylidene)-3-ethyl-4-(substitutephenyl)-2,3-dihydrothiazole derivatives were obtained. Among these compounds, 2-((1-(4-(1H-imidazol-1-yl)phenyl)ethylidene)hydrazineylidene)-4-([1,1′-biphenyl]-4-yl)-3-ethyl-2,3-dihydrothiazole ( 4h ) was chosen as the most active derivative in the series. According to the MTT results, compounds 4h and 4k showed activity with IC₅₀=4.566±0.246 μM and IC₅₀=4.537±0.463 μM, respectively. Unlike other derivatives, compound 4h carries a phenyl ring in the 4th position of the phenyl ring. This bulky group allowed the compound to settle in the enzyme active site. Dynamic studies show that the stability of the compound does not change over 40 ns. RMSD, RMSF and Rg parameters all remained within acceptable limits. The uninterrupted aromatic hydrogen bonding of the enzyme active site with the important amino acids Cys919, Glu885 and Asp1046 proves the inhibitory potential of compound 4h on the VEGFR-2 enzyme. It is thought that more active compounds will be reached with the derivatives to be synthesized starting from compound 4h .     

Determinants of the changes in positive airway pressure for the retitration in patients with obstructive sleep apnea syndrome

Sleep and Biological Rhythms - During long-term follow-up of the patients with obstructive sleep apnea syndrome (OSAS) under the positive airway pressure (PAP) therapy, it waits to be explored...     

Design,Synthesis and Biological Evaluation of New N-Acyl Hydrazones with a Methyl Sulfonyl Moiety as Selective COX-2 Inhibitors

The mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs) is inhibition of specific prostaglandin (PG) synthesis by inhibition of cyclooxygenase (COX) enzymes. The two COX isoenzymes show 60 % similarity. It is known that the nonspecific side effects of conventional NSAIDs are physiologically caused by inhibition of the COX-1 enzyme. Therefore, the use of COX-2 selective inhibitors is seen to be a more beneficial approach in reducing these negative effects. However, some of the existing COX-2 selective inhibitors show cardiovascular side effects. Therefore, studies on the development of new selective COX-2 inhibitors remain necessary. It is important to develop new COX-2 inhibitors in the field of medicinal chemistry. Accordingly, novel N-acyl hydrazone derivatives were synthesized as new COX-2 inhibitors in this study. The hydrazone structure, also known for its COX activity, is important in terms of many biological activities and was preferred as the main structure in the design of these compounds. A methyl sulfonyl pharmacophore was added to the structure in order to increase the affinity for the polar side pocket present in the COX-2 enzyme. It is known that methyl sulfonyl groups are suitable for polar side pockets. The synthesis of the compounds ( 3a – 3j ) was characterized by spectroscopic methods. Evaluation of in vitro COX-1/COX-2 enzyme inhibition was performed by fluorometric method. According to the enzyme inhibition results, the obtained compounds displayed the predicted selectivity for COX-2 enzyme inhibition. Compound 3j showed important COX-2 inhibition with a value of IC₅₀=0.143 uM. Interaction modes between the COX-2 enzyme and compound 3j were investigated by docking studies.