Sensitive quantification of coixol,a potent insulin secretagogue,in Scoparia dulcis extract using high‐performance liquid chromatography combined with tandem mass spectrometry and UV detection

Diabetes is a major global health problem which requires new studies for its prevention and control. Scoparia dulcis , a herbal product, is widely used for treatment of diabetes. Recent studies demonstrate coixol as a potent and nontoxic insulin secretagog from S. dulcis . This study focuses on developing two quantitative methods of coixol in S. dulcis methanol‐based extracts. Quantification of coixol was performed using high‐performance liquid chromatography–tandem mass spectrometry (method 1) and high‐performance liquid chromatography–ultraviolet detection (method 2) with limits of detection of 0.26 and 11.6 pg/μL, respectively, and limits of quantification of 0.78 and 35.5 pg/μL, respectively. S. dulcis is rich in coixol content with values of 255.5 ± 2.1 mg/kg (method 1) and 220.4 ± 2.9 mg/kg (method 2). Excellent linearity with determination coefficients >0.999 was achieved for calibration curves from 10 to 7500 ng/mL (method 1) and from 175 to 7500 ng/mL (method 2). Good accuracy (bias < −8.6%) and precision (RSD < 8.5%) were obtained for both methods. Thus, they can be employed to analyze coixol in plant extracts and herbal formulations.     

A 4×4 metal-semiconductor-metal rectangular deep-ultraviolet detector array of Ga2O3 photoconductor with high photo response

A 4$\times $4 beta-phase gallium oxide ($\beta $-Ga$_{2}$O$_{3}$) deep-ultraviolet (DUV) rectangular 10-fingers interdigital metal-semiconductor-metal (MSM) photodetector array of high photo responsivity is introduced. The Ga$_{2}$O$_{3}$ thin film is prepared through the metalorganic chemical vapor deposition technique, then used to construct the photodetector array via photolithography, lift-off, and ion beam sputtering methods. The one photodetector cell shows dark current of 1.94 pA, photo-to-dark current ratio of 6$\times $10$^{7}$, photo responsivity of 634.15 A$\cdot$W$^{-1}$, specific detectivity of 5.93$\times $10$^{11}$ cm$\cdot$Hz$^{1/2}\cdot$W$^{-1}$ (Jones), external quantum efficiency of 310000%, and linear dynamic region of 108.94 dB, indicating high performances for DUV photo detection. Furthermore, the 16-cell photodetector array displays uniform performances with decent deviation of 19.6% for photo responsivity.     

A photocalibrated NO donor based on N-nitrosorhodamine 6G upon UV irradiation

A N-nitrosated rhodamine 6G acid (NOG) was designed for monitoring the kinetics and the dose of NO release in a real-time fashion with UV irradiation.     

PE AND UV SPECTRA OF LINEAR AND CYCLIC POLYSILANES AND ASSIGNMENT BY AB INITIO CALCULATIONS

Abstract

Ab initio calculations have been performed on linear and cyclic polysilanes including permethylsubstituted compounds. Koopmans' approximation was used for assigning experimentally obtained PE and UV spectra. The PE spectrum of octamethylcyclotetrasilane and the UV spectra of cyclopenta and cyclohexasilane are presented for the first time.     

Preparation and evaluation of lauryl methacrylate monoliths with embedded silver nanoparticles for capillary electrochromatography

In this article, capillary columns constituted by lauryl methacrylate monoliths with embedded silver nanoparticles (AgNPs) were developed and tested. Two incorporation approaches of AgNPs in monoliths were explored. The AgNPs were either photogenerated in situ during polymerization of the monolith by UV irradiation, or incorporated to the polymerization mixture (ex situ). The influence of the AgNP concentration on the morphological and chromatographic properties of the polymer matrix was investigated, and both the in situ and ex situ approaches were comparatively discussed. The morphology of the monoliths was characterized by electron microscopic techniques, and their electrochromatographic performance was also evaluated with test mixtures of neutral compounds (sterols, fatty acid methyl esters, tocopherols, and polyaromatic hydrocarbons).     

Flashlamp Pumped Emulsion Dye Laser

Results of experimental study of flashlamp pumped cc-NPO emulsion dye laser are reported. Superior quality α-NPO emulsion over α-NPO solution in n-hexane is found.     

Anomalous Proton NMR Deshielding in Anilinopyrazoles

In connection with the synthesis of thienobenzodiazepines and certain heterocyclic analogues¹, a number of anilino heterocycle precursors were prepared. Their proton NMR spectra were generally unexceptional with the exclusion of one of the pyrazole isomers which showed a remarkable deshielding of one proton signal in the aniline ring. Further investigations have inferred that this low field shift can be attributed to through speace deshielding by a proximal pyrazole nitrogen lone pair.     

Preparation of UV curing crosslinked polyviologen film and its photochromic and electrochromic performances

Polyether urethane diacrylate matrix (PEUDA) and acrylate-functional viologen (ACV²⁺) were successfully synthesized and characterized in detail by FTIR and ¹H NMR spectra, respectively. Subsequently, they were used to prepare UV curing crosslinked polyviologen film in combination with 2-hydroxyethyl methacrylate (HEMA), trimethylolpropane ethoxylate triacrylate (TMPTA) and diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide (TPO). UV curing approach confined the polyviologen film on ITO electrode, which imparted the film excellent adhesion ability to ITO glass, good solvent resistance, excellent chemical stability, excellent optical and electrochemical properties. The crosslinked PACV²⁺ film exhibited excellent photochromic and electrochromic performances. After UV illumination for 60 s, the crosslinked PACV²⁺ film can swiftly change its color from pale yellow to deep blue, while the optical transmission of crosslinked PACV²⁺ film at 610 nm did not change significantly and still retained about 63.6% after 30 cycles. Simultaneously, the cyclic voltammetry experiment showed the PACV²⁺ film can undergo repeatable electrochemical redox reactions with good reversibility beyond the 10th scan. Furthermore, the electrochromic device composed of the PACV²⁺ film and gel electrolyte film can undergo reversible color change in response to the external voltages of −2.0 V and 2.0 V, respectively, while the contrast of EC device at 610 nm did not change significantly and still retained about 39.5% after 10 cycles. This UV curing approach to preparing viologen-functional film offers a method to preparing large-scale photo- and electrochromic device, which is relatively simple, high productivity, energy saving, and environmental protection.