Thin Film Composite Membranes Derived from Interfacial Polymerization for Nanofiltration and Pervaporation Applications

In this study, thin film composite (TFC) membranes were prepared by interfacial polymerization on a microporous polyethersulfone (PES) substrate. These membranes were studied for salt separation by nanofiltration and ethylene glycol dehydration by pervaporation. The membranes with a layer-by-layer structure based on polyethylenimine (PEI) and trimesoylchloride (TMC) were prepared by sequential reactant depositions and reactions. The membrane properties can be tailored by controlling the number and sequence of the reactant depositions. In general, the PEI-TMC membranes were more permeable than the TMC-PEI membranes. The membrane formed by a single cycle of interfacial polymerization with 3.5 wt% PEI and 0.7 wt% TMC had a positively charged surface and showed a good nanofiltration performance; salt rejections of 95.1% for MgCl2, 94.4% for MgSO4, 80.5% for Na2SO4 and 85.1% for NaCl with a pure water permeation flux of 24.5 L/(m2.h) were obtained at a feed solute concentration of 500 ppm and transmembrane pressure of 0.8 MPa gauge. In another approach, monomeric amine piperazine (PIP) was embedded into the polymeric amine PEI as the amine reactant. Membranes with a single-ply polyamide layer were produced by reacting TMC with mixed amines of PEI and PIP. Incorporation of 10 wt% PIP in PEI resulted in a 6-fold increase in permeation flux while still maintaining a 91.6% MgCl2 rejection. In addition, 2-ply polyamide membranes were prepared by two cycles of PEI-TMC and PIP-TMC interfacial reactions, separately. It was demonstrated that by properly controlling the PIP/PEI concentration ratio, the 2-ply polyamide membranes with both a higher permeation flux and salt rejection than conventional single-ply polyamide membranes could be produced. The effects of chlorine exposure on the nanofiltration performance of the positively-charged polyamide membranes were studied. It was found that the PIP/TMC crosslinks on the outer sublayer improved the chlorine resistance of the membrane. Controlled exposure of the membrane to a low chlorine concentration could improve the nanofiltration performance. The effect of membrane chlorination was intensified at either an alkaline or acidic pH. The customarily used chlorination intensity (ppm.h), which is a composite parameter based on the product of chlorine concentration and chlorination time, was not adequate for use as a standalone parameter to characterize the chlorination conditions. The PEI/TMC nanofiltration membrane was further modified with self-polymerized polydopamine for use in dehydration of ethylene glycol by pervaporation. Deposition of polydopamine either as an outer layer (i.e., on top of the polyamide) or as a transition layer (i.e., between the polyamide and the substrate) would increase the total permeation flux and effectively improve the membrane selectivity. The modified membrane showed a total permeation flux of 81.03 g/(m2.h) and a separation factor of 388 for a feed containing 2.4 wt% water at 38 °C. The presence of inorganic salt NaCl in the feed mixture decreased the permeation fluxes of both water and ethylene glycol, but increased the water content in the permeate

Nove spoznaje i napredak u otkrivanju dizajnerskih benzodiazepina – kratak pregled

This review article takes a closer look at a new class of psychoactive substances called designer benzodiazepines (DBZs) and the challenges of their detection. These are adinazolam, clonazolam, deschloroetizolam, diclazepam, etizolam, flualprazolam, flubromazepam, flubromazolam, phenazepam, and pyrazolam. They are central nervous system depressants and sedatives that can cause psychomotor impairment and increase the overdose risk when combined with other sedatives. DBZs undergo phase I and II metabolism similar to traditional benzodiazepines, but their specific metabolic pathways and the influence of genetic polymorphisms are yet to be clarified. Advances in liquid chromatography-tandem mass spectrometry (LC-MS/MS) have enhanced the method’s sensitivity for DBZs and their metabolites in biological samples and coupled with improved blood sampling methods require less blood for drug monitoring. Further research should focus on elucidating their pharmacokinetic properties and metabolism in humans, especially in view of genetic polymorphisms and drug interactions that could inform clinical treatment choices. Even though we have witnessed important advances in DBZ detection and measurement, further refinements are needed to expand the scope of detectable DBZs and their metabolites. All this should help toxicological research to better identify and characterise the risks of chronic and polydrug abuse and facilitate clinical, forensic, and regulatory responses to this growing issue.Svrha je ovoga preglednog članka dati bolji uvid u djelovanje nove skupine psihoaktivnih tvari zvanih dizajnerski benzodiazepini (DBZ) i u izazove njihova otkrivanja. Poimence, to su adinazolam, klonazolam, deskloroetizolam, diklazepam, etizolam, flualprazolam, flubromazepam, flubromazolam, fenazepam i pirazolam. Riječ je o depresivima i sedativima središnjega živčanog sustava koji mogu oslabiti psihomotornu funkciju te povećati rizik od predoziranja u kombinaciji s ostalim sedativima. DBZ-i prolaze fazu I. i II. biorazgradnje na način sličan onomu tradicionalnih benzodiazepina, no tek nam preostaje razjasniti njihove specifične metaboličke putove i kako na njih utječu genski polimorfizmi. Poboljšanja u tekućinskoj kromatografiji s tandemskom masenom spektrometrijom (engl. liquid chromatographytandem mass spectrometry, krat. LC-MS/MS) povećala su osjetljivost metoda na DBZ-e i njihove metabolite u biološkim uzorcima, a poboljšanja u uzorkovanju krvi smanjila su količine potrebne za praćenje razina tvari. Ipak, potrebna su daljnja istraživanja koja će rasvijetliti njihova farmakokinetička svojstva i metabolizam u ljudi, napose u smislu utjecaja genskih polimorfizama i interakcija lijekova, što će pomoći pri odabiru kliničkog liječenja. Premda smo svjedoci važnih pomaka u otkrivanju i mjerenju DBZ-a, potrebna su daljnja poboljšanja kako bi se povećao opseg DBZ-a i njihovih metabolita koji se ovim metodama mogu otkriti. Sve to trebalo bi ne samo pridonijeti toksikološkim istraživanjima radi boljeg prepoznavanja rizika povezanih s kroničnom kombiniranom zloporabom droga nego i olakšati kliničke, forenzičke i regulatorne postupke kao odgovor na ovaj rastući problem

Tissue Transglutaminase Promotes Drug Resistance and Invasion by Inducing Mesenchymal Transition in Mammary Epithelial Cells

Recent observations that aberrant expression of tissue transglutaminase (TG2) promotes growth, survival, and metastasis of multiple tumor types is of great significance and could yield novel therapeutic targets for improved patient outcomes. To accomplish this, a clear understanding of how TG2 contributes to these phenotypes is essential. Using mammary epithelial cell lines (MCF10A, MCF12A, MCF7 and MCF7/RT) as a model system, we determined the impact of TG2 expression on cell growth, cell survival, invasion, and differentiation. Our results show that TG2 expression promotes drug resistance and invasive functions by inducing epithelial-mesenchymal transition (EMT). Thus, TG2 expression supported anchorage-independent growth of mammary epithelial cells in soft-agar, disrupted the apical-basal polarity, and resulted in disorganized acini structures when grown in 3D-culture. At molecular level, TG2 expression resulted in loss of E-cadherin and increased the expression of various transcriptional repressors (Snail1, Zeb1, Zeb2 and Twist1). Tumor growth factor-beta (TGF-β) failed to induce EMT in cells lacking TG2 expression, suggesting that TG2 is a downstream effector of TGF-β-induced EMT. Moreover, TG2 expression induced stem cell-like phenotype in mammary epithelial cells as revealed by enrichment of CD44+/CD24-/low cell populations. Overall, our studies show that aberrant expression of TG2 is sufficient for inducing EMT in epithelial cells and establish a strong link between TG2 expression and progression of metastatic breast disease

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Recent findings and advancements in the detection of designer benzodiazepines: a brief review

This review article takes a closer look at a new class of psychoactive substances called designer benzodiazepines (DBZs) and the challenges of their detection. These are adinazolam, clonazolam, deschloroetizolam, diclazepam, etizolam, flualprazolam, flubromazepam, flubromazolam, phenazepam, and pyrazolam. They are central nervous system depressants and sedatives that can cause psychomotor impairment and increase the overdose risk when combined with other sedatives. DBZs undergo phase I and II metabolism similar to traditional benzodiazepines, but their specific metabolic pathways and the influence of genetic polymorphisms are yet to be clarified. Advances in liquid chromatography-tandem mass spectrometry (LC-MS/MS) have enhanced the method's sensitivity for DBZs and their metabolites in biological samples and coupled with improved blood sampling methods require less blood for drug monitoring. Further research should focus on elucidating their pharmacokinetic properties and metabolism in humans, especially in view of genetic polymorphisms and drug interactions that could inform clinical treatment choices. Even though we have witnessed important advances in DBZ detection and measurement, further refinements are needed to expand the scope of detectable DBZs and their metabolites. All this should help toxicological research to better identify and characterise the risks of chronic and polydrug abuse and facilitate clinical, forensic, and regulatory responses to this growing issue

A Low-Cost and High-Precision Underwater Integrated Navigation System

The traditional underwater integrated navigation system is based on an optical fiber gyroscope and Doppler Velocity Log, which is high-precision but also expensive, heavy, bulky and difficult to adapt to the development requirements of AUV swarm, intelligence and miniaturization. This paper proposes a low-cost, light-weight, small-volume and low-computation underwater integrated navigation system based on MEMS IMU/DVL/USBL. First, according to the motion formula of AUV, a five-dimensional state equation of the system was established, whose dimension was far less than that of the traditional. Second, the main source of error was considered. As the velocity observation value of the system, the velocity measured by DVL eliminated the scale error and lever arm error. As the position observation value of the system, the position measured by USBL eliminated the lever arm error. Third, to solve the issue of inconsistent observation frequencies between DVL and USBL, a sequential filter was proposed to update the extended Kalman filter. Finally, through selecting the sensor equipment and conducting two lake experiments with total voyages of 5.02 km and 3.2 km, respectively, the correctness and practicality of the system were confirmed by the results. By comparing the output of the integrated navigation system and the data of RTK GPS, the average position error was 4.12 m, the maximum position error was 8.53 m, the average velocity error was 0.027 m/s and the average yaw error was 1.41°, whose precision is as high as that of an optical fiber gyroscope and Doppler Velocity Log integrated navigation system, but the price is less than half of that. The experimental results show that the proposed underwater integrated navigation system could realize the high-precision and long-term navigation of AUV in the designated area, which had great potential for both military and civilian applications