Read by QxMD icon Read


Vahideh Lajevardi, Afsaneh Ghayoumi, Robabeh Abedini, Hamed Hosseini, Azadeh Goodarzi, Zahra Akbari, Kosar Hedayat
BACKGROUND: Melasma's high prevalence and profound psychological impact on patients necessitate efficacious, economical, and safe therapeutic interventions. Adjunctive therapies such as tranexamic acid (TA) can enhance the therapeutic effect of standard treatments like hydroquinone 4% cream (HQ). OBJECTIVE: To conduct an assessor- and analyst-blinded, parallel, superiority, randomized controlled trial to compare the clinical efficacy and safety of oral TA plus HQ vs...
October 20, 2016: Journal of Cosmetic Dermatology
Jone Corrales, Lauren A Kristofco, W Baylor Steele, Gavin N Saari, Jakub Kostal, Edward Spencer Williams, Margaret Mills, Evan P Gallagher, Terrance J Kavanagh, Nancy Simcox, Longzhu Q Shen, Fjodor Melnikov, Julie B Zimmerman, Adelina M Voutchkova-Kostal, Paul T Anastas, Bryan W Brooks
Sustainable molecular design of less hazardous chemicals presents a potentially transformative approach to protect public health and the environment. Relationships between molecular descriptors and toxicity thresholds previously identified the octanol-water distribution coefficient, log D, and the HOMO-LUMO energy gap, ∆E, as two useful properties in the identification of reduced aquatic toxicity. To determine whether these two property-based guidelines are applicable to sublethal oxidative stress (OS) responses, two common aquatic in vivo models, the fathead minnow (Pimephales promelas) and zebrafish (Danio rerio), were employed to examine traditional biochemical biomarkers (lipid peroxidation, DNA damage, total glutathione) and antioxidant gene activation following exposure to eight structurally diverse industrial chemicals (bisphenol A, cumene hydroperoxide, dinoseb, hydroquinone, indene, perfluorooctanoic acid, R-(-)-carvone, tert-butyl hydroperoxide)...
October 17, 2016: Chemical Research in Toxicology
Yunhao Lu, Yanzuo Dong, Xueli Li, Qiang He
The nitration and nitrosation reactions of catechol, resorcinol, and hydroquinone (0.05 mmol/L) with sodium nitrite (0.05 mmol/L) at pH 3 and 37 °C were studied by using liquid chromatography and mass spectrometry (LC-MS) and atom charge analysis, which was aimed to provide chemical insight into the nitrite-scavenging behavior of polyphenols. The 3 benzenediols showed different mechanisms to scavenge nitrite due to their differences in hydroxyl position. Catechol was nitrated with 1 NO2 group at the hydroxyl oxygen, and resorcinol was nitrosated with 2 NO groups at the C2 and C4 (or C6 ) positions of the benzene ring...
October 14, 2016: Journal of Food Science
Mathieu Schwartz, Claude Didierjean, Arnaud Hecker, Jean-Michel Girardet, Mélanie Morel-Rouhier, Eric Gelhaye, Frédérique Favier
Glutathionyl-hydroquinone reductases (GHRs) belong to the recently characterized Xi-class of glutathione transferases (GSTXs) according to unique structural properties and are present in all but animal kingdoms. The GHR ScECM4 from the yeast Saccharomyces cerevisiae has been studied since 1997 when it was found to be potentially involved in cell-wall biosynthesis. Up to now and in spite of biological studies made on this enzyme, its physiological role remains challenging. The work here reports its crystallographic study...
2016: PloS One
Wei Zhou, Jihui Gao, Haiqian Zhao, Xiaoxiao Meng, Shaohua Wu
The reaction between Fe(2+) and H2O2 generates ·OH, which is capable of degrading organic pollutants. However, the weak conversion from Fe(3+) back to Fe(2+) limits its continuous reaction. Here, difference between Fenton system and modified Fenton system (i.e., Hydroquinone-Fenton, 1,4-Bezoquinone-Fenton, NH2OH-Fenton) for the regeneration of Fe(2+) was analyzed. UV-vis spectrometer and redox potential measurements were used to detect Fe(2+) concentration. HPLC was used to detect concentration of ·OH. Results indicated that, different from traditional Fenton system, Fe(2+) could be better regenerated in modified Fenton system...
October 13, 2016: Environmental Technology
Batel Deri, Margarita Kanteev, Mor Goldfeder, Daniel Lecina, Victor Guallar, Noam Adir, Ayelet Fishman
Tyrosinases are responsible for melanin formation in all life domains. Tyrosinase inhibitors are used for the prevention of severe skin diseases, in skin-whitening creams and to avoid fruit browning, however continued use of many such inhibitors is considered unsafe. In this study we provide conclusive evidence of the inhibition mechanism of two well studied tyrosinase inhibitors, KA (kojic acid) and HQ (hydroquinone), which are extensively used in hyperpigmentation treatment. KA is reported in the literature with contradicting inhibition mechanisms, while HQ is described as both a tyrosinase inhibitor and a substrate...
October 11, 2016: Scientific Reports
Sophie De-Botton, Ronit Romm, Guillaume Bensoussan, Maria Hitrik, Sanaa Musa, Dmitri Gelman
The manuscript describes the synthesis and coordination chemistry of a novel diphosphine pincer ligand based on a p-hydroquinone-functionalized dibenzobarrelene scaffold. The p-hydroquinone fragment of the ligand is oxidatively and coordinatively non-innocent and may render new reactivity to the metal center due to implied reversible redox behavior, tautomeric interconversion and metal-hydroxyl/alkoxide coordination switch of the pendant hydroxyl side-arm. Palladium, platinum and iridium complexes were prepared and characterized...
October 12, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Jianhui Xie, Po-Kam Lo, William W Y Lam, Wai-Lun Man, Li Ma, Shek-Man Yiu, Kai-Chung Lau, Tai-Chu Lau
Hydroquinone is readily oxidized by a (salen)ruthenium(vi) nitrido complex in the presence of pyridine to give benzoquinone. Experimental and computational studies suggest that the reaction occurs via a novel mechanism that involves an initial electrophilic attack at the aromatic ring of the hydroquinone by the nitrido ligand.
September 15, 2016: Chemical Communications: Chem Comm
Yevhen I Dubovyk, Viktoriia Yu Harbuzova, Alexander V Ataman
Vitamin K epoxide reductase complex subunit 1 (VKORC1) is integral 163-amino acid long transmembrane protein which mediates recycling of vitamin K 2,3-epoxide to vitamin K hydroquinone and it is necessary for activation of vitamin K-dependent proteins (VKDPs). Herein, the association between G-1639A (rs9923231) and C1173T (rs9934438) single-nucleotide polymorphisms (SNPs) of the VKORC1 gene and ischemic stroke (IS) was tested in Ukrainian population. Genotyping was performed in 170 IS patients and 124 control subjects (total 294 DNA samples) using PCR-RFLP (polymerase chain reaction with following restriction fragment length polymorphism analysis) method...
2016: BioMed Research International
Pascal S Thue, Eder C Lima, Joseph M Sieliechi, Caroline Saucier, Silvio L P Dias, Julio C P Vaghetti, Fabiano S Rodembusch, Flávio A Pavan
First-row transition metals (Co, Ni, Cu and Zn) were successfully used in the preparation of activated carbons from wood biomass via microwave-assisted irradiation. Physical-chemical properties of the produced materials (MWAC) were studied by nitrogen adsorption-desorption curves, SEM, FTIR, UV-vis DRS and synchronous fluorescence spectroscopy, CHN elemental analysis, TGA/DTG, pHzpc, hydrophobic properties, and total acidity and basicity groups. Results showed that the metals were bound successfully in different amounts with surface functional groups of the wood biomass through ion exchange and surface complexation interaction during the impregnation step...
September 29, 2016: Journal of Colloid and Interface Science
Raymond F Pauszek, Goutham Kodali, M Salim U Siddiqui, Robert J Stanley
Chromophoric biomolecules are exploited as reporters of a diverse set of phenomena, acting as internal distance monitors, environment and redox sensors, and as endogenous imaging probes. The extent to which they can be exploited is based on an accurate knowledge of their fundamental electronic properties. Arguably of greatest importance is a precise knowledge of the direction(s) of the absorption transition dipole moment(s) in the molecular frame of reference. Such is the case for flavins, fluorescent redox cofactors utilized for ground and excited state redox and photochemical processes...
September 29, 2016: Journal of the American Chemical Society
Fawzia Ibrahim, Mohie K Sharaf El-Din, Asmaa Kamal El-Deen, Kuniyoshi Shimizu
An eco-friendly sensitive, rapid and less hazardous micellar liquid chromatographic method was developed and validated for the simultaneous analysis of ethamsylate (ETM) and mefenamic acid (MFA) in the presence of hydroquinone (HQ) and 2,3-dimethylaniline (DMA) the main impurities of ETM and MFA, respectively. Good chromatographic separation was attained using Eclipse XDB-C8 column (150 mm × 4.6 mm, 5 μm particle size) adopting UV detection at 300 nm with micellar mobile phase consisting of 0.12 M sodium dodecyl sulfate, 0...
September 27, 2016: Journal of Chromatographic Science
Vera Meester, Daniela J Kraft
Surface morphology is a tool to tune physical properties of colloidal suspensions such as the wettability, viscoelasticity, and depletion attractions. Existing synthesis methods to obtain colloids with a rough surface morphology often result in colloids with nontunable surface properties. Here, we developed a synthetic approach to obtain both spherical and shape-anisotropic hybrid colloids with tunable surface morphology. With our approach, monodisperse linear polystyrene colloids, obtained in large quantities using a dispersion polymerization method, are swollen and cross-linked with styrene and 3-(trimethoxysilyl)propyl methacrylate (TPM) in the presence of the polymerization inhibitor hydroquinone...
October 5, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Xipeng Wei, Honghai Wu, Guangping He, Yufeng Guan
Iron-montmorillonite (Fe-Mt) with delaminated structures was synthesized via the introduction of iron oxides into Na-montmorillonite. Fe-Mt showed significant increases in the available iron content, surface area and pore volume, along with a slight increase in the basal spacing from d001=1.26 (Na-Mt) to 1.53nm (Fe-Mt). The Fenton process was efficient for phenol removal using Fe-Mt as a catalyst under visible light irradiation, and the process had two-stage pseudo-first order kinetics. The overall reaction had a higher degradation rate even when it was only irradiated with visible light for the first 40min period...
September 14, 2016: Journal of Hazardous Materials
Muhsin A Al-Dhalimi, Murtadha H Al-Janabi
BACKGROUND: Lasers have been the treatment of choice for Port-wine stain (PWS). However, only one type of laser is not a panacea for all PWS malformations. This is may be due to the great heterogeneity of phenotypic presentation of this congenital anomaly as color, depth, and the site of the lesion. For the treatment of PWS, flash lamp-pumped pulsed dye laser, carbon dioxide, argon, krypton, copper bromide, frequency-doubled neodymium:yttrium-aluminum-garnet (Nd:YAG), and also intense pulsed light sources can be used...
September 26, 2016: Lasers in Surgery and Medicine
Tuo Li, Zhenwen Zhao, Quan Wang, Pengfei Xie, Jiahai Ma
Quinone-hydroquinone analogues have been proven to be efficient promoters of Fenton reactions by accelerating the Fe(III)/Fe(II) redox cycle along with self-destruction. However, so far there is little information on non-quinone-hydroquinone cocatalyst for Fenton reactions. This study found that cysteine, a common aliphatic amino acid, can strongly enhance Fenton degradation of organic pollutants by accelerating Fe(III)/Fe(II) redox cycle, as quinone-hydroquinone analogues do. Further, cysteine is superior to quinone-hydroquinone analogues in catalytic activity, H2O2 utilization and atmospheric limits...
November 15, 2016: Water Research
Qun Ye, Zhen Zhang, Zhuang Mao Png, Wei Teng Neo, Tingting Lin, Huining Zeng, Hui Xu, Jianwei Xu
2,3,5,6-Tetrakis(5'-dodecylthiophen-2-yl)-benzoquinones and 2,3,5,6-tetrakis(5'-dodecylthiophen-2'-yl)-hydroquinones were prepared via the Stille or Suzuki cross-coupling reactions, followed by oxidation by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in the case that aryl groups are dodecylthiophenyl. 2,3,5,6-Tetrakis(5'-dodecylthiophen-2'-yl)benzoquinone and 2,3,5,6-tetrakis(5'-dodecylthiophen-2'-yl)-1,4-bis(dodecyloxy)benzene underwent the Scholl reaction to give their corresponding predictable cyclization products anthra[2,1-b:3,4-b':6,5-b″:7,8-b‴]tetrathiophene-7,14-dione (3) and anthra[1,2-b:4,3-b':5,6-b″:8,7-b‴]tetrathiophene (5), respectively...
October 7, 2016: Journal of Organic Chemistry
Boštjan Genorio
Several new electroactive diquinone and dihydroquinone derivatives of calix[4]arene bearing anchor functional groups were designed, synthesized and characterized. A method for selective protection of the hydroquinone -OH groups with trimethylsilyl groups (TMS) either on lower-rim or on upper-rim was developed. Four selected molecules - with sulfide anchor groups and carboxylic anchor groups - were adsorbed onto Au(111) single crystal surface using ex-situ and insitu self-assembly methods. Adsorbed molecules were then electrochemically probed with cyclic voltammetry...
2016: Acta Chimica Slovenica
Hansi Jia, Chiteng Zhang, Hansruedi Glatt, Yungang Liu
The standard procedure for the micronucleus test in cell lines requires a short exposure (≤0.5 cell cycle) to the test compounds followed by a long recovery (≥1.5 cell cycle), and in case of negative or equivocal results, a second test with extended exposure (≥2 cell cycles) without or with a recovery time. In general the two procedures are advantageous for detecting clastogens and aneugens, respectively. However, whether the recommended procedures apply to micronucleus tests with promutagens in cell lines genetically engineered for expressing biotransformation enzymes has not been identified...
September 15, 2016: Mutation Research. Genetic Toxicology and Environmental Mutagenesis
Fereshteh Samiee, Federico N Pedron, Dario A Estrin, Liliana Trevani
UV-visible spectroscopic studies of aqueous hydroquinone (HQ) and 1,4-benzoquinone (BQ) have been carried out along with classical molecular dynamics (MD) and quantum calculations. The experimental results confirmed that HQ is stable in hot compressed water up to at least 523 K at 70 bar, but BQ decomposes at temperatures lower than 373 K, leading to the formation of HQ and other nonabsorbing products. Even though benzoquinone is not stable, our study significantly extended the temperature range of other spectroscopic studies, and the spectra of HQ up to 523 K can still be useful for other studies, particularly those related to organic species in deep ocean hydrothermal vents...
October 13, 2016: Journal of Physical Chemistry. B
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"