Computational Study of Two-Phase Flow Morphology in a Nozzle

Multiphase flow meters are widely used in nuclear, petroleum and chemical industries. Here the flow rate is defined indirectly by the differential pressure measurement over the device. An additional measurement is required to estimate average density of the phase mixture. This could be done by means of the gamma-ray, electromagnetic or acoustic tomography. The accuracy of the technique is dependent on flow morphology. The present paper reports the results of CFD-modelling of the gas-liquid flow through the vertical flow meter accompanied by a flow conditioner. The model is used to consider the morphology for three different combinations of liquid and gas flow rates. The model demonstrates high non-uniformities of the flow field at the entrance of the flow meter and generally confirms the agreement of flow morphology with previous experimental observations for vertical pipes.

Dexoxadrol and its bioisosteres: structure, synthesis, and pharmacological activity

© 2020, Springer Science+Business Media LLC. The review addresses the complete anthology of the development and evolution of dexoxadrol derivatives comprising a class of highly efficient NMDA receptor antagonists. Main approaches to the synthesis of dexoxadrol and enantiomeric 1-(2-piperidyl)ethane-1,2-diols and their structural relationship with natural alkaloids from plants of the genera Conium and Astrogalus are considered. Data on biomolecular mechanisms of action of this type of compounds are summarized. The relationships between their chemical structure and biological activity are analyzed. Based on the revealed relationships, different pathways of targeted modifications of the chemical structures of dexoxadrol and its analogues are suggested, which would help in future in overcoming the limitations associated with this type of physiologically active compounds, such as insufficient affinity for the channel binding site of the NMDA-receptor ionophore complex, low hydrolytic stability, anticholinergic side effects, and the production of toxic metabolites. These modifications will make it possible to utilize in full measure the great pharmacological potential of this type of compounds

Nonlinear dimensionality reduction for visualizing toxicity data: Distance-based versus topology-based approaches.

Over the years, a number of dimensionality reduction techniques have been proposed and used in chemoinformatics to perform nonlinear mappings. In this study, four representatives of nonlinear dimensionality reduction methods related to two different families were analyzed: distance-based approaches (Isomap and Diffusion Maps) and topology-based approaches (Generative Topographic Mapping (GTM) and Laplacian Eigenmaps). The considered methods were applied for the visualization of three toxicity datasets by using four sets of descriptors. Two methods, GTM and Diffusion Maps, were identified as the best approaches, which thus made it impossible to prioritize a single family of the considered dimensionality reduction methods. The intrinsic dimensionality assessment of data was performed by using the Maximum Likelihood Estimation. It was observed that descriptor sets with a higher intrinsic dimensionality contributed maps of lower quality. A new statistical coefficient, which combines two previously known ones, was proposed to automatically rank the maps. Instead of relying on one of the best methods, we propose to automatically generate maps with different parameter values for different descriptor sets. By following this procedure, the maps with the highest values of the introduced statistical coefficient can be automatically selected and used as a starting point for visual inspection by the user

Synthesis and antitumor activity of novel pyridoxine-based structural analogs of saccharumoside-B

A series of 11 new pyridoxine-based structural analogs of saccharumoside-B were obtained using original synthetic approach. Antitumor activity of these compounds against nine human tumor cell lines (MCF-7, MDA-MB-231, A-498, SNB-19, M-14, NCI-H322M, HCT-115, HCT-116, and PC-3) was studied, and cytotoxic activity to three normal (HEK-293, Chang Liver, and MSC) cell lines was evaluated. Among the synthesized compounds, 12d, 12e, 13b, 13d, 13e, and 14 exhibited the highest antitumor activity, comparable to that of camptothecin and doxorubicin, but with significantly increased selectivity toward tumor cells. [Figure not available: see fulltext.

Antibacterial activity profile of miramistin in in vitro and in vivo models

© 2020 Background: Miramistin is a widely used antiseptic, disinfectant and preservative, and one of the most popular antimicrobial agents on pharmaceutical market of the Russian Federation (http://www.dsm.ru/en/news/385/). However, there is a lack of reported systematic data on antibacterial efficacy of this agent obtained in accordance with the international standards. Aim: This paper represents a systematic study of antibacterial properties of miramistin. Another objective of this work is to evaluate and compare the exploratory performance of in vitro and in vivo protocols of antiseptics’ efficacy testing using miramistin as the reference antiseptic. Methods: Antibacterial activity of 0.1% and 0.2% aqueous solutions of miramistin against two museum strains of S. aureus (ATCC 209p) and E. coli (CDC F-50) was studied. Three standard in vitro laboratory tests (microdilution test, suspension test, and metal surface test), and one in vivo test (on rat's skin) were used. The study was conducted in accordance with the international regulatory documents. Results: Miramistin showed high bactericidal activity against the studied bacterial pathogens in the standard in vitro tests. Thus, in the microdilution test it showed expressed activity against S. aureus (MIC 8 μg/ml, MBC 16 μg/ml) and E. coli (MIC 32 μg/ml, MBC 128 μg/ml). In the suspension test, miramistin decreased the amount of colony forming units by at least 6 log10 units for S. aureus, and by at least 4.5 log10 units for E. coli. Transition to the metal surface test led to significant decrease of antibacterial activity by 1–3 log10 units as compared to the suspension test. Further dramatic reduction of antiseptic activity (by 3–4 log10 units) was observed in in vivo rat skin test. Addition of a protein contaminant (bovine serum albumin) led to a general decrease in the effectiveness of miramistin against the test pathogens (typically, by 1–2 log10 units). An interesting effect of exposure time-dependent reversal of miramistin's specificity to the studied Gram-positive S. aureus and the Gram-negative E. coli organisms was observed in the metal surface test. Conclusions: The results of this work provide systematic data on antibacterial efficacy of miramistin. They also underscore the need in relevant in vivo models for evaluation of antiseptics' efficacy. While the existing in vitro methods can be successfully applied at the discovery stages, it is necessary to use more realistic in vivo models at more advanced development stages. The observed selectivity reversal effect should be taken into account when carrying out the antiseptics’ efficacy testing and surface disinfection procedures

Synthesis, antitumor activity and structure-activity studies of novel pyridoxine-based bioisosteric analogs of estradiol

A new efficient approach to the synthesis of 6-alkenyl substituted pyridoxine derivatives has been developed. A series of 31 novel alkenyl pyridoxine derivatives, stilbene-based bioisosteric analogs of estradiol, were synthesized. In vitro cytotoxicity of the obtained compounds against MCF-7 (ER+) breast cancer tumor cells was studied using the MTT assay. The most active compounds with IC50, MCF-7 < 10 μM were also tested for cytotoxicity in vitro against MDA-MB-231 (ER-) breast adenocarcinoma cells and conditionally normal human skin fibroblasts (HSF). The patterns of structure-antitumor activity relationships of the obtained compounds were analyzed. The most active compounds were found to contain a six-membered ketal ring, a methyl group in position 5, a 3,4-dimethoxystyryl fragment in positions 2 or 6 of the pyridoxine ring, and a trans-configuration of the double bond. Using the most active compound 5a as a representative cytotoxic agent, we have demonstrated that it has high specificity and antiproliferative activity against MCF-7 (ER+) tumor cells (IC50 < 5 μM), and a higher therapeutic index compared to the reference compound raloxifene (48 versus 5.8). Compound 5a decreased the mitochondrial membrane potential and increased the level of reactive oxygen species in MCF-7 cells, but not MDA-MB-231 cells. Compound 5a did not affect the distribution of cell cycle phases and induced apoptosis in MCF-7 cells, but not MDA-MB-231. Unlike compound 5a, raloxifene decreased mitochondrial potential, increased the ROS level, and induced apoptosis in both MCF-7 and MDA-MB-231 cells, which indicated a lack of selectivity for cells with estrogen receptor expression. It was also shown that compound 5a reduced the level of ERα expression in cells to a lesser extent than raloxifene and, unlike the latter, did not activate the PI3K/Akt signaling pathway