A new bischromanone from the stems of Semecarpus caudata

From an CHCl₃-soluble fraction of the stems of Semecarpus caudata, one new bischromanone named semecarpanone (1), together with 5 known flavonoids (2–6) were isolated. Their structures were elucidated based on interpretation of spectroscopic data. The stereo-configuration of 1 was identified based on the calculated and experimental coupling constants. Compounds 4–6 showed potent tyrosinase inhibitory activity with the IC₅₀ values ranging from 15.0 to 76.3 μM.     

Literally Green Chemical Synthesis of Artemisinin from Plant Extracts

Active pharmaceutical ingredients are either extracted from biological sources—where they are synthesized in complex, dynamic environments—or prepared in stepwise chemical syntheses by reacting pure reagents and catalysts under controlled conditions. A combination of these two approaches, where plant extracts containing reagents and catalysts are utilized in intensified chemical syntheses, creates expedient and sustainable processes. We illustrate this principle by reacting crude plant extract, oxygen, acid, and light to produce artemisinin, a key active pharmaceutical ingredient of the most powerful antimalarial drugs. The traditionally discarded extract of Artemisia annua plants contains dihydroartemisinic acid—the final biosynthetic precursor—as well as chlorophyll, which acts as a photosensitizer. Efficient irradiation with visible light in a continuous‐flow setup produces artemisinin in high yield, and the artificial biosynthetic process outperforms syntheses with pure reagents.     

Radioactivity in airborne particulate and rainwater samples and deposition to ground in Ho Chi Minh City (Vietnam)

In this study, radioactivity of airborne particulate and rainwater samples were analysed during 2016 at three different sites in Ho Chi Minh City, Vietnam. The activities of gross alpha and gross beta measured in airborne particulate are in the range from (<?MDA-7.50) and (0.73–45.41) mBq m^?3 respectively. In rainwater, theirs are in the range from (1.9–4.1) and (14.9–28.6) mBq l^?1 respectively. Mean values of annual deposition fluxes of gross alpha and gross beta were found in the range from (5.56–10.65) and (50.9–70.5) Bq m^?2 y^?1 respectively. The correlation between radioactivity levels and meteorological factors are presented in this paper.     

Isolation and identification of novel α-amylase inhibitors from Euonymus laxiflorus Champ.

Research on Chemical Intermediates - Euonymus laxiflorus Champ. (ELC) has been reported to possess potential antidiabetic activity. The aim of this study is to isolate and identify the active...     

Construction of self-sufficient Z-scheme Ag3PW12O40/TiO2 photocatalysts for the improved visible-light-driven photo-degradation of rhodamine B

Research on Chemical Intermediates - Nanotube titanic acid (denoted as NTA), a tubular mesoporous material, after it undergoes heat-treatment at high temperature, is a novel kind of TiO2 containing...     

Design and preparation of high-aspect-ratio zinc borate whiskers and their effects on mechanical properties of PP nanocomposite

Well-dispersed, high-aspect-ratio 4ZnO·B₂O₃·H₂O whiskers (4ZnO·B₂O₃·H₂O_HARw) were synthesized by a facile hydrothermal method with the aid of ZnSO₄·7H₂O. The formation mechanism was investigated, and the results showed that Zn²⁺ and SO ₄ ^2? ions played a crucial role in the control of 4ZnO·B₂O₃·H₂O_HARw extended along [010] direction. X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG)-differential scanning calorimetry (DSC) results confirmed that the powder was 4ZnO·B₂O₃·H₂O. Scanning electron microscopy (SEM) and TEM showed that the average aspect ratio of the product was about 100. Nanocomposites of surface-modified 4ZnO·B₂O₃·H₂O_SM-HARw/PP were prepared and their mechanical properties measured. The results suggested that the mechanical properties of 4ZnO·B₂O₃·H₂O_SM-HARw/PP composites were superior to composites made with low-aspect-ratio whiskers (4ZnO·B₂O₃·H₂O_SM-LARw), which displayed poorer mechanical properties even at low addition.     

A method to improve crystal quality of CZTSSe absorber layer

Journal of Sol-Gel Science and Technology - In this work, a fabrication process of high crystallinity CZTSSe absorber layer is presented. The CZTS structure is firstly prepared by spin-coating...     

Superparamagnetism and ferrimagnetism of the small particles of magnetite in a silicate matrix

The magnetic behaviour of a basalt glass and glass-ceramic was studied by magnetization measurements between 4 and 800 K as a function of a wide range of magnetic fields (H) between 0 and 60 kG. For the as-annealed glass it was found that nearly all the iron ions behaved as paramagnetic ions. In the samples heat-treated at 700 and 900°C, the magnetization (M) values showed three magnetic components: paramagnetic Fe²⁺ ions, magnetite in a superparamagnetic and in a ferrimagnetic state. This confirmed our previous Mössbauer results. The superparamagnetic behaviour of the fine particles of magnetite was interpreted by Langevin's theory. From the M (H) and M(T) values we evaluated the percentage of each component as a function of temperature, the magnetization values in the saturated states, the mean particle diameter and the particle size distributions.     

Crystal and molecular structure of an ion-pair complex based on [Ni(mnt)<Subscript>2</Subscript>]<Superscript>2−</Superscript> anion and imidazolium derivative cations

A new ion-pair complex, 1-methyl-3-benzylimidazolium bis(maleonitrile-dithiolato) nickelate(II), has been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy and X-ray crystallography. The crystallographic data for the complex: triclinic , a = 8.415(1) Å, b = 9.924(1) Å, c = 11.333(2) Å, = 114.11(1), = 102.46(1), = 100.88(1), V = 801.8(2) ų, Z = 1. The molecular packing pattern showed a completely separated column stacking for cations and anions of the complex along with the b-axis. The anion is not completely planar. The five-membered nickel-containing rings are slightly puckered. The cation, [BzIm]⁺, adopts a conformation where the benzene ring and imidazole ring twisted with the reference plane C10–C11–N3.     

Variational Analysis of Paraconvex Multifunctions

Journal of Optimization Theory and Applications - Our aim in this article is to study the class of so-called $$\rho -$$ paraconvex multifunctions from a Banach space X into the subsets of another...