Preparation of N-Aryl Anthranilic Acid Drugs by Modified Ullmann Coupling Reaction in Ionic Liquids

Russian Journal of Organic Chemistry - N-Aryl anthranilic acid drugs have been synthesized by a simple, environmentally friendly, low-cost, and high-yielding modified Ullmann coupling reaction...     

Tandem Synthesis of Tetrasubstituted NH Pyrroles from Simple Nitriles

An efficient tandem route to obtain tetrasubstituted NH pyrroles in a one-pot manner has been developed, staring from simple nitriles, ethyl bromoacetates, and zinc. This reaction involves oxidative dimerization of the zinc bromide complex of β-enaminoesters using cerium ammonium nitrate (CAN) as an oxidant, affording 2,3,4,5-tetrasubstituted pyrroles in yields up to 91%.     

Enhanced Static Modulated Fourier Transform Spectrometer for Fast Approximation in Field Application

We discuss the data sampling frequency, the spectral resolution, and the limit for non-aliasing in the static modulated Fourier transform spectrometer based on a modified Sagnac interferometer. The measurement was performed in a very short 4 ms, which is applicable for real time field operation. The improved spectrometer characteristics were used to investigate the spectral properties of an InGaAs light emitting diode. In addition, The measured spectral peak was shifted from 6420 cm⁻¹ to 6365 cm⁻¹, as the temperature increased from 25 °C to 40 °C, when the operating current is fixed to be 0.55 A. As the applied current increased from 0.30 A to 0.55 A at room temperature, the spectral width was broadened from 316 cm⁻¹ to 384 cm⁻¹. Compared to the conventional Fourier transform spectrometer, the measured spectral width by the static modulated Fourier transform spectrometer showed a deviation less than 10%, and the spectral peak shift according to the temperature rise showed a difference within 2%.     

Ultraviolet Spectroscopic Detection of Nitrate and Nitrite in Seawater Simultaneously Based on Partial Least Squares

A direct, reagent-free, ultraviolet spectroscopic method for the simultaneous determination of nitrate (NO₃⁻), nitrite (NO₂⁻), and salinity in seawater is presented. The method is based on measuring the absorption spectra of the raw seawater range of 200–300 nm, combined with partial least squares (PLS) regression for resolving the spectral overlapping of NO₃⁻, NO₂⁻, and sea salt (or salinity). The interference from chromophoric dissolved organic matter (CDOM) UV absorbance was reduced according to its exponential relationship between 275 and 295 nm. The results of the cross-validation of calibration and the prediction sets were used to select the number of factors (4 for NO₃⁻, NO₂⁻, and salinity) and to optimize the wavelength range (215–240 nm) with a 1 nm wavelength interval. The linear relationship between the predicted and the actual values of NO₃⁻, NO₂⁻, salinity, and the recovery of spiked water samples suggest that the proposed PLS model can be a valuable alternative method to the wet chemical methods. Due to its simplicity and fast response, the proposed PLS model can be used as an algorithm for building nitrate and nitrite sensors. The comparison study of PLS and a classic least squares (CLS) model shows both PLS and CLS can give satisfactory results for predicting NO₃⁻ and salinity. However, for NO₂⁻ in some samples, PLS is superior to CLS, which may be due to the interference from unknown substances not included in the CLS algorithm. The proposed method was applied to the analysis of NO₃⁻, NO₂⁻, and salinity in the Changjiang (Yangtze River) estuary water samples and the results are comparable with that determined by the colorimetric Griess assay.     

Combinatorial Therapeutic Effect of Inhibitors of Aldehyde Dehydrogenase and Mitochondrial Complex I,and the Chemotherapeutic Drug,Temozolomide against Glioblastoma Tumorspheres

Resident cancer cells with stem cell-like features induce drug tolerance, facilitating survival of glioblastoma (GBM). We previously showed that strategies targeting tumor bioenergetics present a novel emerging avenue for treatment of GBM. The objective of this study was to enhance the therapeutic effects of dual inhibition of tumor bioenergetics by combination of gossypol, an aldehyde dehydrogenase inhibitor, and phenformin, a biguanide compound that depletes oxidative phosphorylation, with the chemotherapeutic drug, temozolomide (TMZ), to block proliferation, stemness, and invasiveness of GBM tumorspheres (TSs). Combination therapy with gossypol, phenformin, and TMZ induced a significant reduction in ATP levels, cell viability, stemness, and invasiveness compared to TMZ monotherapy and dual therapy with gossypol and phenformin. Analysis of differentially expressed genes revealed up-regulation of genes involved in programmed cell death, autophagy, and protein metabolism and down-regulation of those associated with cell metabolism, cycle, and adhesion. Combination of TMZ with dual inhibitors of tumor bioenergetics may, therefore, present an effective strategy against GBM by enhancing therapeutic effects through multiple mechanisms of action.     

Upgrading Solid Digestate from Anaerobic Digestion of Agricultural Waste as Performance Enhancer for Starch-Based Mulching Biofilm

Developing a green and sustainable method to upgrade biogas wastes into high value-added products is attracting more and more public attention. The application of solid residues as a performance enhancer in the manufacture of biofilms is a prospective way to replace conventional plastic based on fossil fuel. In this work, solid digestates from the anaerobic digestion of agricultural wastes, such as straw, cattle and chicken manures, were pretreated by an ultrasonic thermo-alkaline treatment to remove the nonfunctional compositions and then incorporated in plasticized starch paste to prepare mulching biofilms by the solution casting method. The results indicated that solid digestate particles dispersed homogenously in the starch matrix and gradually aggregated under the action of a hydrogen bond, leading to a transformation of the composites to a high crystalline structure. Consequently, the composite biofilm showed a higher tensile strength, elastic modulus, glass transition temperature and degradation temperature compared to the pure starch-based film. The light, water and GHG (greenhouse gas) barrier properties of the biofilm were also reinforced by the addition of solid digestates, performing well in sustaining the soil quality and minimizing N₂O or CH₄ emissions. As such, recycling solid digestates into a biodegradable plastic substitute not only creates a new business opportunity by producing high-performance biofilms but also reduces the environmental risk caused by biogas waste and plastics pollution.     

Experimental simulation of the Unruh effect on an NMR quantum simulator

A triad mode resonance, or three-wave resonance, is typical of dynamical systems with quadratic nonlinearities. Suspended cables are found to be rich in triad mode resonant dynamics. In this paper, modulation equations for cable’s triad resonance are formulated by the multiple scale method. Dynamic conservative quantities, i.e., mode energy and Manley-Rowe relations, are then constructed. Equilibrium/dynamic solutions of the modulation equations are obtained, and full investigations into their stability and bifurcation characteristics are presented. Various bifurcation behaviors are detected in cable’s triad resonant responses, such as saddle-node, Hopf, pitchfork and period-doubling bifurcations. Nonlinear behaviors, like jump and saturation phenomena, are also found in cable’s responses. Based upon the bifurcation analysis, two interesting properties associated with activation of cable’s triad resonance are also proposed, i.e., energy barrier and directional dependence. The first gives the critical amplitude of high-frequency mode to activate cable’s triad resonance, and the second characterizes the degree of difficulty for activating cable’s triad resonance in two opposite directions, i.e., with positive or negative internal detuning parameter.     

Positively charged liposomes consisting of the KTTKS pentapeptide conjugated with rhodamine increase rhodamine toxicity in E. coli and zebrafish embryo

Liposomes composed of cell‐penetrating peptide derivatives increased transport across the cell membrane. Conjugating rhodamine to a cell‐penetrating peptide increased the toxicity of rhodamine in E. coli and zebrafish embryos. A similar total protein inhibition pattern with different intensities, indicating that the interaction pathways of the rho‐KTTKS‐CONH₂ monomer and liposomes were the same. It suggests that the rho‐KTTKS‐CONH₂ liposomes showed higher toxicity because better transport across the cell membrane increased the effective concentration inside cells. The staining of zebrafish embryos using rho‐KTTKS‐CONH₂ liposomes showed a longer retention time, suggesting that it can penetrate deeper tissues or organs in zebrafish.     

Mixing of Racemic Poly(L-lactide)/Poly(D-lactide) Blend with Miscible Poly(D,L-lactide):Toward All Stereocomplex-type Polylactide with Strikingly Enhanced SC Crystallizability

Stereocomplex-type polylactide (SC-PLA) consisting of alternatively arranged poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) chains has gained a good reputation as a sustainable engineering plastic with outstanding heat resistance and durability,however its practical applications have been considerably hindered by the weak SC crystallizability.Current methods used to enhance the SC crystallizability are generally achieved at the expense of the precious bio-renewability and/or bio-degradability of PLAs.Herein,we demonstrate a feasible method to address these challenges by incorporating small amounts of poly(D,L-lactide) (PDLLA) into linear high-molecular-weight PLLA/PDLA blends.The results show that the incorporation of the atactic PDLLA leads to a significant enhancement in the SC crystallizability because its good miscibility with the isotactic PLAs makes it possible to greatly improve the chain mixing between PLLA and PDLA as an effective compatibilizer.Meanwhile,the melt stability (i.e.,the stability of PLLA/PDLA chain assemblies upon melting) could also be improved substantially.Very intriguingly,SC crystallites are predominantly formed with increasing content and molecular weight of PDLLA.More notably,exclusive SC crystallization can be obtained in the racemic blends with 20 wt％ PDLLA having weight-average molecular weight of above 1 ×10s g/mol,where the chain mixing level and intermolecular interactions between the PLA enantiomers could be strikingly enhanced.Overall,our work could not only open a promising horizon for the development of all SC-PLA-based engineering plastic with exceptional SC crystallizability but also give a fundamental insight into the crucial role of PDLLA in improving the SC crystallizability of PLLA/PDLA blends.     

Failure analysis of Cu(In,Ga)Se2 photovoltaic modules: degradation mechanism of Cu(In,Ga)Se2 solar cells under harsh environmental conditions

High‐temperature‐induced and humidity‐induced degradation behaviors were investigated through the failure analysis of encapsulated Cu(In,Ga)Se₂ (CIGS) modules and non‐encapsulated CIGS cells. After being exposed to high temperature (85 °C) for 1000 h, the efficiency loss of CIGS modules and the resistivities of the aluminum‐doped zinc oxide (AZO) layer, CIGS layer, and Mo layer were slightly increased. After damp heat (DH) testing (85 °C/85% RH), the efficiency of some modules decreased significantly accompanied by discoloration, and in these areas, the resistivity of the AZO layers increased markedly. The causes of degradation of CIGS cells after high temperature and DH tests were suggested through X‐ray photoelectron spectroscopy analysis. The high‐temperature‐induced degradation behaviors were revealed to be increases in series resistance of the CIGS cells, due to the adsorption of oxygen on the AZO, CIGS, and Mo layers. The degradation behavior after DH (85 °C/85% RH) exposure was caused by the adsorption of oxygen, as well as the generation of Zn(OH)₂ due to water molecules. In particular, the humidity‐induced degradation behavior in discolored CIGS modules was ascribed to the generation of Zn(OH)₂ and carboxylic acids in the AZO layer, due to a chemical reaction between the AZO, ethylene‐vinyl acetate copolymer, and water. Copyright © 2014 John Wiley & Sons, Ltd.