Abstract

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

Abstract

3-hydroxy-2-phenylchromen-4-one (HF) is a flavonols that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N₉-glycosidic bond. Cyclodextrins are able to form host-guest complexes with hydrophobic molecules given the unique nature imparted by their structure.As a result, these molecules have found a number of applications in a wide range of fields. The inclusion complex of HF with 2HP-β-CD is prepared by various synthetic method such as physical method (PM), kneading method (KM) and co-precipitation method (CP). The solid inclusion complex is characterized by UV, luminescence spectra, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The anticancer activity of the solid complex is performed against breast cancer cell line and it is noticed that there is no much better activity than the HF alone. Both the HF and its solid complex showed the poor anticancer activity against MDA MB 231 cell line. 

Abstract

Silver-based photocatalytic semiconducting materials have drawn the attention of reseachers for their high visible photocatalytic activity. However, the silver-based photocatalytic semiconducting material exhibits light corrosion during the photocatalytic reaction, and the photocatalytic stability is poor. Therefore, improvingthe photocatalytic stability and inhibition of light corrosion of silver-based photocatalytic semiconductor materials have been the focus of attention. In this paper, according to the principle of photocatalysis and the principle of photo-corrosion, it is proposed to improve the photogenerated electrons and hole separation of photocatalytic semiconductor materials, to rapidly transfer photogenerated electrons, to inhibit photogenerated electrons and Ag + to prevent light corrosion, Stability of the catalyst. Ag2CO3 / GO composite photocatalytic materials were synthesized by precipitation method using polystyrene as photocatalyst. The characterization and photocatalytic performance tests showed that the graphene has a good auxiliary effect, which can promote the separation of photogenerated electrons and holes of Ag2CO3 and transfer the photogenerated electrons into O2 in H2O in time, thus suppressing the light of Ag2CO3 / GO photocatalytic materials Corrosion phenomenon, improve the photocatalytic performance. Ag2CO3 / GO-1.0 has the best catalytic activity for the catalytic activity and stability of Ag2CO3 / GO in the photocatalytic decomposition of methyl orange. Therefore, graphene as a photocatalytic auxiliaries can effectively improve the photocatalytic stability of silver-based photocatalytic materials and have some reference significance for improving the stability of other photocatalytic materials which are prone to light corrosion.

Abstract In this paper, the spectral characteristics of the interaction between lead and bovine serum albumin (BSA) were analyzed by fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy. The effects of pH, bovine serum albumin concentration, lead ion concentration and ionic strength on the spectra of lead ion-bovine serum albumin system were investigated, and the best testing condition is to determine the interaction between lead and BSA by testing the peak changes or displacement in the UV spectrum analysis. Fluorescence spectroscopy showed that lead ion could induce the fluorescence quenching of bovine serum albumin. The influence of lead ion on the secondary structure of protein was analyzed by infrared spectroscopy. It was found that β-angle increased, α-helix decreased and β-slice increased.

Abstract

Native and lyophilized shredded muscle tissue of beef and its main ingredients (muscle fibers, stroma, stroma proteins) prepared via consecutive treatment with water, saline (Weber solution ) and alkaline (0.6 M NaOH) solutions as well as colloidal solutions-extracts of sarcoplasmic substances, actomyosin and mucopolysaccharide complexes are comparatively studies by attenuated total internal reflection infrared (ATIR) and diffuse reflectance electronic spectroscopy. A high sensitivity, efficiency, extended options and advanced prospects of diffuse spectroscopy are considered in respect of the characterization of  the component composition of complex solid-state and liquid biological systems in medical and veterinary practice.

Abstract

This article deals with acetonitrile physico-chemical properties and its mixtures with water. It covers the information about isotherms of such parameters of the acetonitrile-water binary system as density, viscosity, permeation coefficient, refraction index, optic density, a boiling point isobar. Authors suggest a generalized criterion of acetonitrile polarity. The article also discusses means of polarity assessment and eluotropic strength of mobile phases on the basis of acetonitrile mixtures with water with application of generalized criteria. Special attention is paid to the options of acetonitrile application in various extraction methods of chromatographic sample preparation. The article also reveals advantages and problems of acetonitrile application as a mobile phase modifying agent in the HPLC reversed-phase and as a hydrophilic extra-agent in liquid-liquid extraction.