A note on teleparallel Killing vector fields in Bianchi type VIII and IX spaceben times in teleparallel theory of gravitation

In this paper we classify Bianchi type VIII and IX space—times according to their teleparallel Killing vector fields in the teleparallel theory of gravitation by using a direct integration technique. It turns out that the dimensions of the teleparallel Killing vector fields are either 4 or 5. From the above study we have shown that the Killing vector fields for Bianchi type VIII and IX space—times in the context of teleparallel theory are different from that in general relativity.     

Multisolitons of the $$U(N)$$ generalized Heisenberg magnet model and the Yang–Baxter relation

Theoretical and Mathematical Physics - We use the binary Darboux transformation to obtain exact multisoliton solutions of the $$U(N)$$ generalized Heisenberg magnet model and present the solutions...     

Dithieno[3,2‐b:2′,3′‐d]pyrrole Cored p‐Type Semiconductors Enabling 20 % Efficiency Dopant‐Free Perovskite Solar Cells

Organic p‐type semiconductors with tunable structures offer great opportunities for hybrid perovskite solar cells (PVSCs). We report herein two dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) cored molecular semiconductors prepared through π‐conjugation extension and an N‐alkylation strategy. The as‐prepared conjugated molecules exhibit a highest occupied molecular orbital (HOMO) level of ?4.82 eV and a hole mobility up to 2.16×10^?4 cm² V^?1 s^?1. Together with excellent film‐forming and over 99 % photoluminescence quenching efficiency on perovskite, the DTP based semiconductors work efficiently as hole‐transporting materials (HTMs) for n‐i‐p structured PVSCs. Their dopant‐free MA_0.7FA_0.3PbI_2.85Br_0.15 devices exhibit a power conversion efficiency over 20 %, representing one of the highest values for un‐doped molecular HTMs based PVSCs. This work demonstrates the great potential of using a DTP core in designing efficient semiconductors for dopant‐free PVSCs.     

Nonstatic axisymmetric universe model and its evolution

An axisymmetric rotating universe model is crossed with a time-dependent factor. Its evolution is studied. It turns out that for a particular choice it behaves exactly like that of a flat Friedmann universe.     

A review on catalytic role of heterogeneous acidic catalysts during glycerol acetylation to yield acetins

Glycerol is a colorless, odorless, and non-toxic compound and has application in food, paint, and pharmaceutical industries. At an industrial scale, glycerol (GL) commonly forms as a by-product of soap and biodiesel producing industries. To utilize the excess GL of biodiesel industry, former has been employed as a building block to manufacture value added products such as acetins by fine chemical manufacturers. Acetins, including monoacertin (MA), diacetin (DA) and triacetin (TA), has diverse application such as in cosmetics, fuel additives, pharmaceuticals, leather, and food processing. Specifically, TA is employed as an additive to improve the anti-knocking property of gasoline and viscosity and cold flow properties of biofuel. The acetins are frequently produced at an industrial scale via a homogeneous Brønsted acid catalysed process employing acetic acid or acetic anhydride as an acetylating agent. Homogeneous acid catalysts are corrosive, non-reusable, difficult to separate from the reaction mixture, and sensitive to water, which is formed as a by-product during the glycerol acetylation. To address the issues, Brønsted or Lewis acidic group have been immobilized over various matrices (e.g., mixed metal oxides, mesoporous silica, ion exchange resins, carbon, zeolites, and magnetic nanoparticles) to prepare the heterogeneous acidic catalysts for the glycerol acetylation. Both the sites assisted the carbocation mediated esterification of glycerol with acetic acid or acetic anhydride. The ease of catalyst separation from the reaction mixture and reusability are the major advantages of their usage. However, lower conversion levels with low product selectivity, catalysts deactivation, and partial dissolution in the reaction mixture are the concerns related to the catalysts. To address these issues, novel catalyst preparation techniques to incorporate the variety of active sites over the matrix surface have been employed in the literature, which will be highlighted in detail in the present review article.     

Ion chromatography coupled with fluorescence/UV detector: A comprehensive review of its applications in pesticides and pharmaceutical drug analysis

Ion chromatography (IC) is a well-known technique for trace determination of inorganic ions and small organic acids. Recently, it has also appeared as a promising alternative to reverse phase chromatography for the determination of polar pesticides and pharmaceutical drugs in various sample matrices. Therefore, this study aims to provide a comprehensive overview of the application of IC coupled to fluorescence (FLD) or UV detector for the determination of pesticides and pharmaceutical drugs in samples from all walks of life. Apart from advantages and limitations, a short comparison of IC-FLD/UV with other techniques especially reverse-phase chromatography was drawn to envision future research efforts in this direction. Finally, several related areas such as IC hyphenation with different detectors (spectroscopic and spectrometer), miniaturization, automation, green chemistry, mobile phase, column, sample preparation, etc., were discussed to highlight its application for the determination of a wide range of analytes in the complex sample matrix.     

Photodetachment of hydrogen negative ion near inelastic surfaces: Arbitrary laser polarization direction

The photodetachment of hydrogen negative ion near different inelastic surfaces is investigated by the semiclassical closed orbit theory for arbitrary laser polarization direction . A two‐term formula of photodetachment cross section consisting of a smooth background term and an oscillatory term is derived. The oscillatory term contains an extra angular factor that describes the dependence of oscillations in total cross section on the laser polarization direction. It is observed that the amplitude of oscillations in cross section reaches maximum at when laser polarization is parallel to the z‐axis and it approaches zero as the laser polarization direction becomes perpendicular to the z‐axis. It is also observed that as the reflection coefficient , which accounts for the inelastic behavior of the surfaces, increases the amplitude of oscillation also increases. © 2015 Wiley Periodicals, Inc.     

A computational study of H2 dissociation on silver surfaces: the effect of oxygen in the added row structure of Ag110

We studied computationally the activation of H(2) on clean planar (111), (110) and stepped (221) as well as oxygen pre-covered silver surfaces using a density functional slab model approach. In line with previous data we determined clean silver to be inert towards H(2) dissociation, both thermodynamically and kinetically. The reaction is endothermic by approximately 40 kJ mol(-1) and exhibits high activation energies of approximately 125 kJ mol(-1). However, oxygen on the surface, modeled by the reconstructed surface p(2 x 1)O/Ag(110) that exhibits -O-Ag-O- added rows, renders H(2) dissociation clearly exothermic and kinetically feasible. The reaction was calculated to proceed in two steps: first the H-H bond is broken at an Ag-O pair with an activation barrier E(a) approximately 70 kJ mol(-1), then the H atom bound at an Ag center migrates to a neighboring O center with E(a) approximately 12 kJ mol(-1).     

Anti-Disturbance Compensation-Based Nonlinear Control for a Class of MIMO Uncertain Nonlinear Systems

Multi-Inputs-Multi-Outputs (MIMO) systems are recognized mainly in industrial applications with both input and state couplings, and uncertainties. The essential principle to deal with such difficulties is to eliminate the input couplings, then estimate the remaining issues in real-time, followed by an elimination process from the input channels. These difficulties are resolved in this research paper, where a decentralized control scheme is suggested using an Improved Active Disturbance Rejection Control (IADRC) configuration. A theoretical analysis using a state-space eigenvalue test followed by numerical simulations on a general uncertain nonlinear highly coupled MIMO system validated the effectiveness of the proposed control scheme in controlling such MIMO systems. Time-domain comparisons with the Conventional Active Disturbance Rejection Control (CADRC)-based decentralizing control scheme are also included.     

Cissus subtetragona Planch. Ameliorates Inflammatory Responses in LPS-induced Macrophages,HCl/EtOH-induced Gastritis,and LPS-induced Lung Injury via Attenuation of Src and TAK1

Several Cissus species have been used and reported to possess medicinal benefits. However, the anti-inflammatory mechanisms of Cissus subtetragona have not been described. In this study, we examined the potential anti-inflammatory effects of C. subtetragona ethanol extract (Cs-EE) in vitro and in vivo, and investigated its molecular mechanism as well as its flavonoid content. Lipopolysaccharide (LPS)-induced macrophage-like RAW264.7 cells and primary macrophages as well as LPS-induced acute lung injury (ALI) and HCl/EtOH-induced acute gastritis mouse models were utilized. Luciferase assays, immunoblotting analyses, overexpression strategies, and cellular thermal shift assay (CETSA) were performed to identify the molecular mechanisms and targets of Cs-EE. Cs-EE concentration-dependently reduced the secretion of NO and PGE₂, inhibited the expression of inflammation-related cytokines in LPS-induced RAW264.7 cells, and decreased NF-κB- and AP-1-luciferase activity. Subsequently, we determined that Cs-EE decreased the phosphorylation events of NF-κB and AP-1 pathways. Cs-EE treatment also significantly ameliorated the inflammatory symptoms of HCl/EtOH-induced acute gastritis and LPS-induced ALI mouse models. Overexpression of HA-Src and HA-TAK1 along with CETSA experiments validated that inhibited inflammatory responses are the outcome of attenuation of Src and TAK1 activation. Taken together, these findings suggest that Cs-EE could be utilized as an anti-inflammatory remedy especially targeting against gastritis and acute lung injury by attenuating the activities of Src and TAK1.