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(Nadeen Al-Janabi, Abdullatif Alfutimie, Flor R. Siperstein, Xiaolei Fan, pp. 103-107)
Metal-organic frameworks (MOFs), as versatile and promising adsorbents, have attracted much attention for gas adsorption and separation due to their high adsorption capacity and tuneable structural/chemical properties. Coordinatively unsaturated divalent metal cations (or open metal sites, OMSs) in certain MOFs, e.g. unsaturated copper centres in Cu3(BTC)2 MOF, h
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Natural products and their derivatives represent a rich source for the discovery and development of new cancer therapeutic drugs. Bioactive components derived from natural sources including marine compounds have been shown to be effective agents in the clinic or in preclinical settings. In the present review, we present a story of discovery, synthesis and evaluation of three synthetic tricyclic pyrroloquinone (TPQ) alkaloid analogs as cancer therapeutic agents. Chemical synthesis of these compounds (BA-TPQ, TBA-TPQ, and TCBA-TPQ) has been accomplished and the mechanisms of action (MOA) and structure-activity relationships (SAR) have been investigated. In the past, the complexity of chemical synthesis and the lack of well-defined MOA have dampened the enthusiasm for the development of some makaluvamines. Recent discovery of novel molecular targets for these alkaloids (unrelated to inhibition of Topoisomerase II) warrant further consideration as clinical candidates in the future. In addition to the establishment of novel synthetic approaches and demonstration of in vitro and in vivo anticancer activities, we have successfully demonstrated that these makaluvamines attack several key molecular targets, including the MDM2-p53 pathway, providing ample opportunities of modulating the compound structure based on SAR and the use of such compounds in combination therapy in the future.
As an advanced and new technology in molecular simulation fields, ReaxFF reactive force field has been developed and widely applied during the last two decades. ReaxFF bridges the gap between quantum chemistry (QC) and non-reactive empirical force field based molecular simulation methods, and aims to provide a transferable potential which can describe many chemical reactions with bond formation and breaking. This review presents an overview of the development and applications of ReaxFF reactive force field in the fields of reaction processes, biology and materials, including (1) the mechanism studies of organic reactions under extreme conditions (like high temperatures and pressures) related with high-energy materials, hydrocarbons and coals, (2) the structural properties of nanomaterials such as graphene oxides, carbon nanotubes, silicon nanowires and metal nanoparticles, (3) interfacial interactions of solid-solid, solid-liquid and biological/inorganic surfaces, (4) the catalytic mechanisms of many types of metals and metal oxides, and (5) electrochemical mechanisms of fuel cells and lithium batteries. The limitations and challenges of ReaxFF reactive force field are also mentioned in this review, which will shed light on its future applications to a wider range of chemical environments.
Heterogeneous catalysis with core-shell structures has been a large area of focus for many years. This paper reviews the most recent work and research in core-shell catalysts utilizing noble metals, specifically gold, as the core within a metal oxide shell. The advantage of the core-shell structure lies in its capacity to retain catalytic activity under thermal and mechanical stress, which is a pivotal consideration when synthesizing any catalyst. This framework is particularly useful for gold nanoparticles in protecting them from sintering so that they retain their size, structure, and most importantly their catalytic efficiency. The different methods of synthesizing such a structure have been compiled into three categories: seed-mediated growth, post selective oxidation treatment, and one-pot chemical synthesis. The selective oxidation of carbon monoxide and reduction of nitrogen containing compounds, such as nitrophenol and nitrostyrene, have been studied over the past few years to evaluate the functionality and stability of the core-shell catalysts. Different factors that could influence the catalyst’s performance are the size, structure, choice of metal oxide shell and noble metal core and thereby the interfacial synergy and lattice mismatch between the core and shell. In addition, the morphology of the shell also plays a critical role, including its porosity, density, and thickness. This review covers the synthesis and characterization of gold-metal oxide core-shell structures, as well as how they are utilized as catalysts for carbon monoxide (CO) oxidation and selective reduction of nitrogen-containing compounds.
A review of recent research related to microporous polymeric membranes formed via thermally induced phase separation (TIPS) and the morphologies of these membranes is presented. A summary of polymers and suitable diluents that can be used to prepare these microporous membranes via TIPS are summarized. The effects of different kinds of polymer materials, diluent types, cooling conditions, extractants and additive agents on the morphology and performance of TIPS membranes are also discussed. Finally new developments in TIPS technology are summarized.
Small pore zeolites, containing 8-rings as the largest, are widely employed as catalysts in the process of methanol-to-olefins (MTO). Reactants and products diffuse with constraints through 8-rings and this is one of the reaction bottlenecks related to zeolite micropore topology. Small pore zeolites and silicon-aluminophosphates(SAPOs) containing cavities, where olefins are mainly formed through the hydrocarbon pool (HP) mechanism, are frequently tested for MTO. Shape selectivity of transition states within the side-chain methylation will be reviewed as this is one of the controlling steps of the MTO process, with particular attention to the role of hexamethylbenzene (HMB) and heptamethylbenzenium cation (HeptaMB+), which are the most tipically detected reaction intermediates, common to the paring and side-chain routes within the HP mechanism. The relative stability of these and other species will be reviewed in terms of confinement effects in different cage-based zeolites. The role of the different alkylating agents, methanol, dimethyl ether (DME), and surface methoxy species (SMS) will also be reviewed from the computational viewpoint.
Microfluidic chip has been applied in various biological fields owing to its low-consumption of reagents, high throughput, fluidic controllability and integrity. The well-designed microscale intermediary is also ideal for the study of cell biology. Particularly, microfluidic chip is helpful for better understanding cell-cell interactions. A general survey of recent publications would help to generalize the designs of the co-culture chips with different features. With ingenious and combinational utilization, the chips facilitate the implementation of some special co-culture models that are highly concerned in a different spatial and temporal way.
Amyloid peptides are renowned to be related to neurodegenerative diseases, however, a fruitful avenue is to employ them as high-performance nanomaterials. These materials benefit from the intrinsic outstanding mechanical robustness of the amyloid backbone made of b-strands. In this work, we exploited amyloid-like fibrils as functional material to attach pristine L-cysteine aggregates (cystine oligomers) and gold nanoparticles, without the need of templating compounds. This work will open new avenues on functional materials design and their realisation.
Water induced decomposition of Cu3(BTC)2 (BTC= benzene-1,3,5-tricarboxylate) metal-organic framework (MOF) was studied using dynamic water vapour adsorption. Small-angle X-ray scattering, Fourier transform infrared spectroscopy and differential scanning calorimetry analyses revealed that the underlying mechanism of Cu3(BTC)2 MOF decomposition under humid streams is the interpenetration of water molecules into Cu-BTC coordination to displace organic linkers (BTC) from Cu centres.
The antioxidant and antitumor effects as well as the immunomodulatory activities of crude and purified polyphenol extract from blueberries were investigated. The antioxidant and antitumor effects of the polyphenol extract were measured both in vitro and in vivo, and their effect on the immune systems of CD-1 tumor-bearing mice were also analyzed. In vitro assays demonstrated that blueberry purified polyphenol extract (BBPP) exhibited higher antioxidant activities than blueberry crude polyphenol extract (BBCP), but the opposite effect was observed in vivo. Both the in vitro and in vivo antitumor activity and the immunity assay showed that BBCP not only inhibited tumor growth, but also significantly improved the immunity of the mice. According to physical and histological studies, the CD-1 tumor-bearing mice treated with the polyphenol extract, especially high doses of BBCP experienced a higher quality of life than the positive control group (treated with cyclophosphamide). These results indicate that BBCP has significant antioxidant and antitumor activities and that it can enhance the immunity of CD-1 tumor-bearing mice.
This paper presents a novel synthesis method for designing integrated processes for oil-in-water (O/W) emulsions treatment. General superstructure involving alternative separation technologies is developed and modelled as a mixed integer linear programming (MILP) model for maximum annual profit. Separation processes in the superstructure are divided into three main sections of which the pretreatment and final treatment are limited to the selection of one alternative (or bypass) only, while within the intermediate section various combinations of different technologies in series can be selected. Integrated processes composed of selected separation techniques for given ranges of input chemical oxygen demand (COD) can be proposed by applying parametric analyses within the superstructure approach. This approach has been applied to an existing industrial case study for deriving optimal combinations of technologies for treating diverse oil-in-water emulsions within the range of input COD values between 1000 mg?L?1 and 145000 mg?L?1. The optimal solution represents a flexible and profitable process for reducing the COD values below maximal allowable limits for discharging effluent into surface water.
Nowadays a lot of low-grade heat is wasted from the industry through the off- and flue-gasses with different compositions. These gases provide the sensitive heat with utilisation potential and latent heat with the components for condensation. In this paper, process integration methodology has been applied to the partly condensed streams. A hot composite curve that represents the gas mixture cooling according to equation of state for real gases was drawn to account the gas-liquid equilibrium. According to the pinch analysis methodology, the pinch point was specified and optimal minimal temperature difference was determined. The location of the point where gas and liquid phases can be split for better recuperation of heat energy within heat exchangers is estimated using the developed methodology. The industrial case study of tobacco drying process off-gasses is analysed for heat recovery. The mathematical model was developed by using MathCad software to minimise the total annualised cost using compact plate heat exchangers for waste heat utilisation. The obtained payback period for the required investments is less than six months. The presented method was validated by comparison with industrial test data.
Heteropoly compounds with the general formula Cs1M0.5x+H3?0.5xP1.2Mo11VO40 (M= Fe, Co, Ni, Cu or Zn) and Cs1CuyH3?2yP1.2Mo11VO40 (y = 0.1, 0.3 or 0.7) were synthesized and then used as catalysts for the selective oxidation of methacrolein to methacrylic acid. The effects of the transition metals on the structure and activity of the catalysts were investigated. FTIR spectra showed that the transition metal-doped catalysts maintained the Keggin structure of the undoped catalysts. X-ray diffraction results indicated that before calcination, the catalysts doped with Fe and Cu had cubic secondary structures, while the catalysts doped with Co, Ni or Zn had both triclinic and cubic phases and the Co-doped catalyst had the highest content of the triclinic form. Thermal treatment can decrease the content of the triclinic phase. NH3 temperature-programmed desorption and H2 temperature-programmed reduction results showed that the transition metals changed the acid and redox properties of the catalysts. The addition of Fe or Cu had positive effects on the activities of the catalyst which is due to the improvement of the electron transfer between the Fe or Cu and the Mo. The effects of the copper content on structure and catalytic activity were also investigated. The Cs1Cu0.3H2P1.2Mo11VO40 catalyst had the best performance for the selective oxidation of methacrolein to methacrylic acid.
A novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the crosslinker, N,N′-methylenebisacrylamide and the initiator, potassium persulfate. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy confirmed that the acrylic acid was grafted onto the backbone of the corn starch, that the organo-mordenite participated in the polymerization, and that the addition of organo-mordenite improved the surface morphology of the hydrogel composite. The swelling capacity of the hydrogel composite was evaluated in distilled water, and solutions with different pH values, and various salt solutions. It was found that the incorporation of 10 wt-% organo-mordenite enhanced the water absorbency by 144% (from 268 to 655 g·g−1) and swelling was extremely sensitive to the pH values, the concentration of the salt solution and cation type. Swelling kinetics and water diffusion mechanism of the hydrogel composite in distilled water were also discussed. Moreover, the hydrogel composite showed excellent reversibility of water absorption even after five repetitive cycles and the hydrogel composite exhibited significant environmental-responsiveness by changing the swelling medium from distilled water to 0.1 mol·L−1 NaCl solution. In addition, the loading and release of urea by the hydrogel composite were tested and the nutrient-slow-release capability of this material was found to be suitable for many potential applications.
Aqueous solutions of methyldiethanolamine (MDEA) and piperazine (PZ) are commonly used solvent nowadays. In this work a thermodynamic analysis with the Electrolyte-NRTL model has been performed for systems composed of acidic gases and MDEA+PZ aqueous solution. ASPEN Plus® has been used for thermodynamic modeling. Values of binary interaction parameters for liquid phase activity coefficients have been estimated from regressions of experimental data. Moreover, the influence of the interactions between ion pairs and MDEA or PZ molecular species has been analyzed. The final aim is to obtain a reliable tool for design and simulation of absorption and stripping columns, fundamentals also in order to carry out energy saving studies.
