Ancillary Ligand Effects on Heteroleptic IrIII Dye in Dye-Sensitized Photocatalytic CO2 Reduction: Photoaccumulation of Charges on Arylated Bipyridine Ligand and Its Control on Catalytic Performance

Herein, we report the synthesis, and photochemical and -physical properties, as well as the catalytic performance, of a series of heteroleptic Ir^III photosensitizers (IrPSs), [Ir(C^N)₂(N^N^Aryl)]⁺, possessing ancillary ligands that are varied with aryl-substituents on bipyridyl unit [C^N=(2-pyridyl)benzo[b]thiophen-3-yl (btp); N^N^Aryl=4,4′-Y₂-bpy (Y=−Ph or −PhSi(Ph)₃]. We found that the π-extension of bipyridyl ligand by aryl-substitution put bipyridyl ligand in use as an electron relay unit that performed charge accumulation before delivering to the catalytic center, greatly improving the overall CO₂-to-CO conversion activities. In a typical run, the aryl-substituted IrPS ( ^{t Bu} IrP-Ph^Si )-sensitized homogeneous systems (IrPS+Re^I catalyst) gave a turnover number of 1340 (Φ_CO=24.2 %) at the early stage of photolysis (<5 h). This study demonstrates that the π-character modulation on the ancillary bipyridyl ligand is critical for forthcoming catalytic performance.     

Simultaneous determination of spinosad,temephos, and piperonyl butoxide in animal‐derived foods using LC–MS/MS

Pesticides, which are used as plant protection products, can enter the food chain, and exposure to these xenobiotics can cause a wide array of health problems in humans. Therefore, the objective of the present study was to develop an analytical method for the simultaneous determination of residual spinosad (sum of spinosyn A and D), temephos and piperonyl butoxide in porcine muscle, egg, milk, eel, flatfish and shrimp (sampling period: February to June 2018) using liquid chromatography–triple quadrupole tandem mass spectrometry (LC–MS/MS). The target analytes were extracted with a combination of acidified acetonitrile and ethyl acetate and subsequently purified with original QuEChERS kits (composed of magnesium sulfate and sodium chloride) as well as n‐hexane. All analytes were separated on a reversed‐phase analytical column using a mobile phase of (A) 0.1% formic acid containing 10 mm ammonium formate in distilled water and (B) methanol. Good linearity (R² ≥ 0.980) was achieved over the tested concentration range (3.5–35 μg/kg for spinosyn A; 1.5–15 μg/kg for spinosyn D; 5–50 μg/kg for temephos and piperonyl butoxide) in matrix‐matched standard calibrations. Fortified samples at three spiking levels yielded recoveries in the range of 71–105% with relative standard deviations ≤9.2%. The applicability of the method was evaluated via evaluating samples collected from a large wholesale market located in Seoul, and none of the samples contained any of the target analytes. In conclusion, the current approach is simple, efficient and reliable and can successfully determine the residual levels of spinosad, temephos and piperonyl butoxide in complex animal‐derived food products.     

Influence of extraction process on Cs isotope ratios for Fukushima Daiichi nuclear power plant accident-contaminated soil

Journal of Radioanalytical and Nuclear Chemistry - The influence of extraction process on Cs isotope ratios was investigated by thermal ionization mass spectrometry (TIMS) for nitric-acid (HNO3)...     

Comparative hydrolysis analysis of cellulose samples and aspects of its application in conservation science

Cellulose - Knowledge about the carbohydrate composition of pulp and paper samples is essential for their characterization, further processing, and understanding the properties. In this study, we...     

Effects of Induced Exosomes from Endometrial Cancer Cells on Tumor Activity in the Presence of Aurea helianthus Extract

Endometrial cancer (EC) cells metastasize to various regions, including the ovaries, fallopian tubes, cervix, blood, liver, bone, and brain. Various carcinogens are known to cause EC. Exosomes are released from several types of cells and contain various cellular components. In this study, flow cytometry and quantitative PCR were used to evaluate marker levels, cell migration, cell invasion, and mitochondrial membrane potential, and cellular senescence tests were used to estimate cancer activity. The microRNAs were profiled using next-generation sequencing. Although tocopherol-α and rutin content in Aurea helianthus is high, A. helianthus extract was more useful in modulating tumor activity compared to the two aforementioned substances. Notably, we established that the extract induced bioactive exosomes in EC cells, and profiling of miRNAs in the extract-inducing exosomes (EIE) indicated their potency to be developed as a biological drug. The extract and EIE contributed to the following five biological process categories for EC cells: (1) cell migration and invasion suppression, (2) cellular senescence activation by attenuating mitochondrial membrane potential and enhancing autophagy, (3) reproductive cancer activity attenuation, (4) drug susceptibility activation, and (5) EIE containing miRNAs associated with decreasing inflammation.     

Copolymer Particles with Incorporated Gold and Silver Nanoparticles to Absorb Short‐Wavelength Scattering in Full‐Color Photonic Glasses

Photonic glasses (PGs) have fascinated researchers because the structural colors that are reflected from PGs are angle independent. However, low color saturation, especially for colors at longer wavelengths, is an obstacle for realizing full‐color PGs. It is reported that the form‐factor‐(FF)‐derived reflections that degrade the color saturation of PGs can be removed by embedding Ag and Au nanoparticles (NPs) into copolymers. Styrene and 4‐vinylpyridne copolymer particles are prepared and used as nanotemplates to synthesize AgNPs and AuNPs. The wavelength of the FF‐derived reflections in relation to the diameter of the particles is estimated. NPs with an absorption spectrum corresponding to the calculated values are then selectively embedded in the copolymer particles. PGs fabricated with AgNP‐ and AuNP‐embedded copolymer particles exhibit fewer FF‐derived reflections owing to the surface‐plasmon‐resonance‐induced absorption of the embedded NPs. Using these FF‐reduced PGs, angle‐independent full‐color PG pigments are realized.     

A rapid,simple and reliable HPLC‐triple quadrupole tandem mass spectrometer method for a simultaneous quantification of irinotecan and its active metabolite 7‐ethyl‐10‐hydroxycamptothecin (SN38) in mouse plasma

A simple, fast and reliable high‐performance liquid chromatography–triple quadrupole mass spectrometry method (HPLC‐MS/MS method) was developed, validated and used for the simultaneous quantification of irinotecan and 7‐ethyl‐10‐hydroxycamptothecin (SN38) in heparinized mouse plasma. Camptothecin was used as the internal standard. A single‐step protein precipitation without evaporation and reconstitution steps was adopted as sample processing method. Our bioanalytical method was validated in compliance with the guidelines from the European Medicines Agency. The lower limit of quantification for both irinotecan and SN38 was 5 ng/mL. The calibration curves for both analytes fitted to a 1/x² weighted linear regression model and ranged from 5 to 1000 ng/mL. The intra‐run and inter‐run precisions were within 8.6%, and the intra‐run and inter‐run accuracies were within 96.4?103.9%. Our validated bioanalytical method was successfully applied to the pharmacokinetic study in mice, in which 4 mg/kg irinotecan was intraperitoneally injected. Copyright © 2014 John Wiley & Sons, Ltd.     

Improved thin film transistor performance of solution-processed-zinc-oxide nanorods with spin-on-glass capping layer

Due to the vulnerability of various organic and oxide materials to the atmosphere, a protective layer is often used to improve device performance and stability. In this study, we use a spin-on-glass (SOG) layer to encapsulate a solution-processed-zinc-oxide (ZnO) film. ZnO loses oxygen very easily to the atmosphere and even loses Zn at relatively low temperatures. An SOG capping layer prevents the loss of oxygen without degrading its crystalline properties. We demonstrate the properties of a bottom-gate transistor with a capping layer; it shows improved electrical properties with a mobility of 0.5 cm²/V.s. and stability. Physical characterization reveals that the defect density with a capping layer is much lower than it is without it. A capping layer can also prevent the loss of oxygen at the annealing temperature of 350 °C.