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C Jayakumar, C Maria Magdalane, K Kaviyarasu, M Anbu Kulandainathan, Boniface Jeyaraj, M Maaza
A simple and reliable voltammetric sensor for simultaneous determination of Catechol (CT) and Hydroquinone (HQ) was developed by electrodepositing the gold nanoparticles on the surface of the Glassy Carbon Electrode (GCE). The cyclic voltammograms in a mixed solution of CT and HQ have shown that the oxidation peaks become well resolved and were separated by 110 mV, although the bare GCE gave a single broad oxidation peak. Moreover, the oxidation peak currents of both CT and HQ were remarkably increased three times in comparison with the bare GCE...
July 1, 2018: Journal of Nanoscience and Nanotechnology
Ying Wu, Jixiao Wang, Bin Ou, Song Zhao, Zhi Wang, Shichang Wang
Electrochemical polymerization of aniline is one of the most promising methods to prepare polyaniline (PANI) materials. However, during this process, the electrolyte solution must be replaced after electropolymerization of a certain time because of the generation and the accumulation of the by-products, which have significant effects on the morphology, purity and properties of PANI products. Treatment and recycling of the used electrolyte solution are worthwhile to study to reduce the high treatment cost of the used electrolyte solution containing aniline and its polymerization by-products...
February 12, 2018: Nanomaterials
Tiehu He, Deyan Liu, Junji Yuan, Jiafa Luo, Stuart Lindsey, Nanthi Bolan, Weixin Ding
The effects of biochar combined with the urease inhibitor, hydroquinone, and nitrification inhibitor, dicyandiamide, on gaseous nitrogen (N2O, NO and NH3) emissions and wheat yield were examined in a wheat crop cultivated in a rice-wheat rotation system in the Taihu Lake region of China. Eight treatments comprised N fertilizer at a conventional application rate of 150kgNha-1 (CN); N fertilizer at an optimal application rate of 125kgNha-1 (ON); ON+wheat-derived biochar at rates of 7.5 (ONB1) and 15tha-1 (ONB2); ON+nitrification and urease inhibitors (ONI); ONI+wheat-derived biochar at rates of 7...
February 8, 2018: Science of the Total Environment
Tobias Mann, Wolfram Gerwat, Jan Batzer, Kerstin Eggers, Cathrin Scherner, Horst Wenck, Franz Stäb, Vincent J Hearing, Klaus-Heinrich Röhm, Ludger Kolbe
Tyrosinase is the rate-limiting enzyme of melanin production and, accordingly, is the most prominent target to inhibit hyperpigmentation. Numerous tyrosinase inhibitors have been identified, but most of those lack clinical efficacy because they were identified using mushroom tyrosinase as the target. Therefore, we used recombinant human tyrosinase to screen a library of 50,000 compounds and compared the active screening hits with well-known whitening ingredients. Hydroquinone and its derivative arbutin only weakly inhibited human tyrosinase with a half-maximal inhibitory concentration (IC50) in the millimolar range, while kojic acid showed a weak efficacy (IC50 > 400 μM)...
February 7, 2018: Journal of Investigative Dermatology
Jun Li, Jianfei Xia, Feifei Zhang, Zonghua Wang, Qingyun Liu
A highly and simply sensitive electrochemical sensor was presented for the simultaneous determination of hydroquinone (HQ) and catechol (CT) in the water based on copper centered metal-organic framework-graphene composites (Cu-MOF-GN) [Cu-MOF = Cu3(BTC)2 (BTC = 1, 3, 5-benzenetricarboxylicacid)] modified glassy carbon electrode (Cu-MOF-GN/GCE). The modification procedure was carried out through casting metal-organic framework-graphene oxide composites (Cu-MOF-GO) on the bare glassy carbon electrode and followed by the transformation of Cu-MOF-GO to Cu-MOF-GN by an electrochemical reduction...
May 1, 2018: Talanta
Hao Luo, Hairong Liang, Yuting Chen, Shaoyun Chen, Yongchun Xu, Longmei Xu, Jiaxian Liu, Kairu Zhou, Jucheng Peng, Guoqiang Guo, Bei Lai, Li Song, Hui Yang, Linhua Liu, Jianming Peng, Zhidong Liu, Lin Tang, Wen Chen, Huanwen Tang
Hydroquinone (HQ), one of the major metabolic products of benzene, is a carcinogen, which induces apoptosis and inhibit proliferation in lymphoma cells. microRNA-7-5p (miR-7-5p), a tumor suppressor, participates in various biological processes including cell proliferation and apoptosis regulation by repressing expression of specific oncogenic target genes. To explore whether miR-7-5p is involved in HQ-induced cell proliferation and apoptosis, we assessed the effect of miR-7-5p overexpression on induction of apoptosis analyzed by FACSCalibur flow cytometer in transfection of TK6 cells with miR-7-5p mimic (TK6- miR-7-5p)...
February 5, 2018: Chemico-biological Interactions
Alexander V Lisov, Oksana V Belova, Nataliya G Vinokurova, Tatiana V Semashko, Anatolii G Lobanok, Alexey A Leontievsky
This work investigated the regulatory role of the interaction between cellobiose dehydrogenase (CDH) and β-glucosidase (β-GLU) in the conversion of cellobiose into cellobionolactone or glucose in vitro. To study the regulation, the two enzymes were isolated from the culture medium of the fungus Cerrena unicolor grown on a medium with microcrystalline cellulose. The enzymes were obtained in an electrophoretically homogeneous state. Their properties were studied. Both enzymes had acidic pH optima and were more stable in the acidic pH range...
February 8, 2018: Journal of Basic Microbiology
Sai Das, Soumen K Maiti
One of the pertinent issues in the field of energy science today is the quest for an abundant source of hydrogen or hydrogen equivalents. In this study, phenyl-p-benzoquinone (pPBQ) has been used to generate a molecular store of hydrogen equivalents (phenyl-p-hydroquinone; pPBQH2) from thein vivo splitting of water by photosystem II of the marine cyanobacterium Synechococcus elongatus BDU 70542. Using this technique, 10.8 μmol of pPBQH2 per mg chlorophyll a can be extracted per minute, an efficiency that is orders of magnitude higher when compared to the techniques present in the current literature...
February 3, 2018: Journal of Photochemistry and Photobiology. B, Biology
Leander Sützl, Christophe V F P Laurent, Annabelle T Abrera, Georg Schütz, Roland Ludwig, Dietmar Haltrich
The CAZy auxiliary activity family 3 (AA3) comprises enzymes from the glucose-methanol-choline (GMC) family of oxidoreductases, which assist the activity of other AA family enzymes via their reaction products or support the action of glycoside hydrolases in lignocellulose degradation. The AA3 family is further divided into four subfamilies, which include cellobiose dehydrogenase, glucose oxidoreductases, aryl-alcohol oxidase, alcohol (methanol) oxidase, and pyranose oxidoreductases. These different enzymes catalyze a wide variety of redox reactions with respect to substrates and co-substrates...
February 6, 2018: Applied Microbiology and Biotechnology
Anna S Tolmacheva, Evgeny A Ermakov, Valentina N Buneva, Georgy A Nevinsky
We have carried out an analysis of whether blood IgG antibodies can protect humans from oxidative stress by oxidizing different harmful compounds. A somewhat unexpected result was obtained. We show here for the first time that healthy human sera IgGs with the peroxidase (in the presence H2O2) efficiently oxidize different compounds: 3,3'-diaminobenzidine (1; DAB), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (2; ATBS), o-phenylenediamine (3; OPD), homovanillic acid (4; HVA), α-naphthol (5), 5-aminosalicylic acid (6; 5-ASA) and 3-amino-9-ethylcarbazole (7; AEC), but seven of nine IgG preparations from different volunteers cannot oxidize p-hydroquinone (8: pHQ)...
January 2018: Royal Society Open Science
Ashraf M Badawi, Mai Abdelraouf Osman
Background: Melasma is a difficult-to-treat hyperpigmentary disorder. Ablative fractional laser (AFL)-assisted delivery of topically applied drugs to varied targets in the skin has been an area of ongoing study and research. Objective: The objective of this study was to evaluate the efficacy and safety of fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser as an assisted drug delivery for enhancing topical hydroquinone (HQ) permeation into the skin of melasma patients...
2018: Clinical, Cosmetic and Investigational Dermatology
Yue Li, Yujuan Fan, Huizong Su, Qian Wang, Guofu Li, Yiyang Hu, Jian Jiang, Bo Tan, Furong Qiu
1. Tanshinone I (TSI) is a lipophilic diterpene in Salvia miltiorrhiza with versatile pharmacological activities. However, metabolic pathway of TSI in human is unknown. 2. In this study, we determined major metabolites of TSI using a preparation of human liver microsomes (HLMs) by HPLC-UV and Q-Trap mass spectrometer. A total of 6 metabolites were detected, which indicated the presence of hydroxylation, reduction as well as glucuronidation. 3. Selective chemical inhibition and purified cytochrome P450 (CYP450) isoform screening experiments revealed that CYP2A6 was primarily responsible for TSI Phase I metabolism...
January 23, 2018: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
Marta Maria Pereira da Silva Neves, María Begoña González-García, Alejandro Pérez-Junquera, David Hernández-Santos, Pablo Fanjul-Bolado
In this work, a turn-off photoluminescent sensing proof-of-concept based on blue luminescent graphene quantum dots (GQDs) as the fluorescent probe was developed. For that purpose, GQDs optical response was related with the catalytic enzymatic activity of alkaline phosphatase (ALP), in the presence of hydroquinone diphosphate (HQDP). The hydrolysis of HQDP by ALP generated hydroquinone (HQ). The oxidation of HQ, enzymatically produced, to p-benzoquinone (BQ) resulted in the quenching of GQDs fluorescence (FL)...
January 21, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
Karlo Jurica, Irena Brčić Karačonji, Vesna Benković, Nevenka Kopjar
This study investigated the mechanisms of hydroquinone toxicity and assessed the relationships between its cytotoxic, genotoxic, and cytogenetic effects tested at 8, 140, and 280 μg mL-1 in human peripheral blood lymphocytes exposed for 24 h. The outcomes of the treatments were evaluated using the apoptosis/necrosis assay, the alkaline comet assay, and the cytokinesis-block micronucleus (CBMN) cytome assay. The tested hydroquinone concentrations produced relatively weak cytotoxicity in resting lymphocytes, which mostly died via apoptosis...
December 20, 2017: Arhiv za Higijenu Rada i Toksikologiju
Hyun Sik You, Junggil Kim, Songhee Han, Doo-Sik Ahn, Jean Sun Lim, Sang Kyu Kim
Conformational isomers of hydroquinone and their 1:1 clusters with water have been spatially separated using the Stark deflector in the supersonic jet. Trans-hydroquinone (HyQ) conformer with zero dipole moment is little influenced by inhomogeneous electric fields whereas cis-conformer with nonzero dipole moment (2.38 D) is significantly deflected from the molecular beam axis into the direction along which the strong field gradient is applied. Resonant two photon ionization carried out by shifting the laser position perpendicular to the molecular beam axis after the Stark deflector then gives an exclusive S1-S0 excitation spectrum of the cis-conformer only, making possible immaculate conformer-specific spectroscopy and dynamics...
January 16, 2018: Journal of Physical Chemistry. A
Hyewon Hwang, Jae Hoon Lee, In Gyu Choi, Joon Weon Choi
Hydrothermal liquefaction (HTL) of lignocellulosic biomass has been widely investigated for the production of renewable and alternative bio-crude oil. In this study, catalytic hydrothermal processing of two biomasses (larch and Mongolian oak) was performed using different K2CO3 concentrations (0, 0.1, 0.5, 1.0wt% of solvent) to improve fuel yield and properties. HTL oil, hydrochar, water soluble fraction (WSF) and gas were characterized and carbon balance was investigated. As a result, the maximum yield of HTL oil, 27...
January 15, 2018: Environmental Technology
Hao Tian, Yan Jun Ma, Wan Yi Li, Jian Wen Wang
Triclosan (TCS), a widely used antimicrobial and preservative agent, is an emerging contaminant in aqueous and soil environment. Microbial degradation of TCS has not been reported frequently because of its inhibition of microbe growth. To explore the new microbial resources for TCS biodegradation, fungal endophytes were isolated and screened for the degradation potential. The endophytic strain B4 isolated from Artemisia annua L. showed higher degradation efficiency and was identified as Penicillium oxalicum based on its morphology and ITS sequences of ribosomal DNA...
January 13, 2018: Environmental Science and Pollution Research International
Maxim Ivanov, Denan Wang, Tushar Navale, Sergey Lindeman, Rajendra Rathore
To achieve long-range charge transport/separation and, in turn, bolster the efficiency of modern photovoltaic devices, new molecular scaffolds are needed that can self-assemble in two-dimensional (2D) arrays while maintaining both intra- and inter-molecular electronic coupling. In an isolated molecule of pillarene, a single hole delocalizes intramolecularly via hopping amongst the circularly arrayed hydroquinone ether rings. The crystallization of pillarene cation radical produces a 2D self-assembly with three intermolecular dimeric (sandwich-like) contacts...
January 11, 2018: Angewandte Chemie
Izabela Wysocka, Ewa Kowalska, Konrad Trzciński, Marcin Łapiński, Grzegorz Nowaczyk, Anna Zielińska-Jurek
The combination of TiO₂ photocatalyst and magnetic oxide nanoparticles enhances the separation and recoverable properties of nanosized TiO₂ photocatalyst. Metal-modified (Me = Pd, Au, Pt, Cu) TiO₂/SiO₂@Fe₃O₄ nanocomposites were prepared by an ultrasonic-assisted sol-gel method. All prepared samples were characterized by X-ray powder diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), Mott-Schottky analysis and photoluminescence spectroscopy (PL)...
January 7, 2018: Nanomaterials
Hyejin Lee, Kyung Ah Cheong, Ji-Young Kim, Nan-Hyung Kim, Minsoo Noh, Ai-Young Lee
Extracellular interleukin 1 alpha (IL-1α) released from keratinocytes is one of the endpoints for in vitro assessments of skin irritancy. Although cells dying via primary skin irritation undergo apoptosis as well as necrosis, IL-1α is not released in apoptotic cells. On the other hand, active secretion has been identified in interleukin-1 receptor antagonist (IL-1ra), which was discovered to be a common, upregulated, differentially-expressed gene in a microarray analysis performed with keratinocytes treated using cytotoxic doses of chemicals...
January 9, 2018: Biomolecules & Therapeutics
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