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Open Access May 20, 2021

Bioconcentration Factor of Polychlorinated Biphenyls and Its Correlation with UV- and IR-Spectroscopic data: A DFT based Study

Abstract Polychlorinated biphenyls (PCBs) are important class of persist organic pollutants that were used as a component of paints especially in printings, as plastificator of plastics and insulating materials in transformers and capacitors, heat transfer fluids, additives in hydraulic fluids in vacuum and turbine pumps. There is always a need to establish reliable procedures for predicting the [...] Read more.
Polychlorinated biphenyls (PCBs) are important class of persist organic pollutants that were used as a component of paints especially in printings, as plastificator of plastics and insulating materials in transformers and capacitors, heat transfer fluids, additives in hydraulic fluids in vacuum and turbine pumps. There is always a need to establish reliable procedures for predicting the bioconcentration potential of chemicals from the knowledge of their molecular structure, or from readily measurable properties of the substance. Hence, correlation and prediction of biococentration factors (BCFs) based on λmax and vibration frequencies of various bonds viz υ(C-H) and υ(C=C) of biphenyl and its fifty-seven derivatives have been made. For the study, the molecular modeling and geometry optimization of the PCBs have been performed on workspace program of CAChe Pro 5.04 software of Fujitsu using DFT method. UV-visible spectra for each compound were created by electron transition between molecular orbitals as electromagnetic radiation in the visible and ultraviolet (UV-visible) region is absorbed by the molecule. The energies of excited electronic states were computed quantum mechanically. IR spectra of transitions for each compound were created by coordinated motions of the atoms as electromagnetic radiation in the infrared region is absorbed by the molecule. The force necessary to distort the molecule was computed quantum mechanically from its equilibrium geometry and thus frequency of vibrational transitions was predicted. Project Leader Program associated with CAChe has been used for multiple linear regression (MLR) analysis using above spectroscopic data as independent variables and BCFs of PCBs as dependent variables. The reliability of correlation and predicting ability of the MLR equations (models) are judged by R2, R2adj, se, q2L10O and F values. This study reflected clearly that UV and IR spectroscopic data can be used to predict BCFs of a large number of related compounds within limited time without any difficulty.
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Editorial Article
Open Access June 09, 2022

Theoretical and Experimental Analysis of Miniaturization of Conventional Oscillatory Flow Technology

Abstract The requirement for any configuration of a chemical or biochemical reactor is the presence of efficient mixing to enhance heat and mass transfer as needed for the application of interest. Furthermore, as an Oscillatory Flow (OF) reactor has a combination of flow oscillation and baffled tube configuration, which has the potential to ensure efficient mixing, heat transfer, and mass transfer. In this [...] Read more.
The requirement for any configuration of a chemical or biochemical reactor is the presence of efficient mixing to enhance heat and mass transfer as needed for the application of interest. Furthermore, as an Oscillatory Flow (OF) reactor has a combination of flow oscillation and baffled tube configuration, which has the potential to ensure efficient mixing, heat transfer, and mass transfer. In this way, an efficient mixing in an OF reactor is able to tackle any type of resistance in any chemical process from polymer synthesis to enzyme production. It has been observed that an OF reactor improved both conversion and selectivity of the relevant reaction by efficient mixing and transport properties. However, this technology was not still extended to mini-fluidic configuration via process intensification methods and so far, a novel approach for enhanced mixing at reduced scales was not explored. This work explores the application of OF technology in mini-fluidics. The feasibility analysis of Oscillatory Flow Technology in mini channels has been investigated using theoretical correlations from Conventional Oscillatory flow technology in process equipment. As a preliminary step in the process intensification of OF technology in mini channels, The Nusselt number (Nu) and pressure drop values are predicted from the literature and it has been observed that the transfer operations are also improved when oscillatory flow is applied in mini channels compared to commercial mini contactors such as corning heart shaped reactor. The plot between energy dissipation vs. mixing evaluated from theoretical calculations was drawn and compared with mini-fluidic mixers reported in literature. The most common mini-fluidic mixer is corning heart shaped reactor used for comparison with the proposed minichannel. Because of this analysis, the novel mixing geometries was expected to develop for various chemical processing applications. The OFT experimental set up was developed to create oscillatory flow via either forward rotation or backward rotation of valve. Furthermore, pressure vs. time profile and flow vs. time profile for the given OF mini fluidic arrangement is initially investigated and described. Preliminary experimental results are provided for an OF generator, intended for use in subsequent experiments exploring mini-fluidic mixers with OF technology.
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Article
Open Access August 12, 2021

Minimal Invasive Extracorporeal Circulation (MiECC) in Car-diac Surgery: A Narrative Review

Abstract The heart remained a mystery for many years and was considered surgically untouchable. With the use of extracorporeal circulation, there has been a revolution in this area. Due to its mechanical components and interactions with blood, cardiopulmonary bypass (CPB) can cause significant changes in the body. Factors such as contact between artificial materials and blood, continuous flow, [...] Read more.
The heart remained a mystery for many years and was considered surgically untouchable. With the use of extracorporeal circulation, there has been a revolution in this area. Due to its mechanical components and interactions with blood, cardiopulmonary bypass (CPB) can cause significant changes in the body. Factors such as contact between artificial materials and blood, continuous flow, hemodilution, hypothermia and anticoagulation affect all organs during CPB, and may result in various complications. The minimally invasive extracorporeal circulation (MiECC) system was developed to minimize the contact of blood with air and foreign surfaces during conventional CPB. In addition, the biocompatibility of the components that make up the MiECC circuits increased, which reduced the inflammatory response. The absence of a venous reservoir and shorter lines allow the prime volume to be used to decrease, which also reduces the damage to the blood elements, and consequently, the need for blood transfusion. The MiECC system also has its downsides, the most important one being the difficulty in removing the air that can enter through the venous line, the impairment of the pump function, and embolization. During the use of these systems, perfusion safety and communication with the whole team must be at the highest level. In line with this information, the use of these systems can become standard in cardiac surgery with new technological additions.
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Review Article

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