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https://www.readbyqxmd.com/read/28324654/a-general-strategy-for-visible-light-decaging-based-on-the-quinone-trimethyl-lock
#1
David P Walton, Dennis A Dougherty
Visible-light triggered quinone trimethyl locks are reported as a general design for long-wavelength photoremovable protecting groups for alcohols and amines. Intramolecular photoreduction unmasks a reactive phenol that undergoes fast lactonization to release alcohols and amines. Model substrates are released in quantitative yield along with well-defined, colorless hydroquinone byproducts. Substituent modifications of the quinone core allow absorption from 400-600 nm.
March 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28317530/depigmentation-therapies-for-vitiligo
#2
REVIEW
Pearl E Grimes, Rama Nashawati
The general goals of medical management of vitiligo are to repigment vitiliginous areas of skin and to stabilize the progression of depigmentation. However, for some patients with vitiligo affecting extensive body surface areas who are unresponsive to repigmentation therapies, depigmentation of the remaining normal skin may be a better choice. Candidates for depigmentation therapy should be carefully screened and patient education is essential. Permanent topical therapies used for depigmentation include monobenzyl ether of hydroquinone, 4-methoxyphenol, and 88% phenol...
April 2017: Dermatologic Clinics
https://www.readbyqxmd.com/read/28293954/an-all-organic-proton-battery
#3
Rikard Emanuelsson, Mia Sterby, Maria Strømme, Martin Sjödin
Rechargeable batteries that use organic matter as the capacity-carrying material have previously been considered a technology for the future. Earlier batteries in which both the anode and cathode consisted of organic material required significant amounts of conductive additives and were often based on metal-ion electrolytes containing Li(+) or Na(+). However, we have used conducting poly(3,4-ethylenedioxythiophene) (PEDOT), functionalized with anthraquinone (PEDOT-AQ) or benzonquinone (PEDOT-BQ) pendant groups as the negative and positive electrode materials, respectively, to make an all-organic proton battery devoid of metals...
March 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28286944/multiresponsive-vesicles-composed-of-amphiphilic-azacalix-4-pyridine-derivatives
#4
Shi-Xin Fa, Xu-Dong Wang, Qi-Qiang Wang, Yu-Fei Ao, De-Xian Wang, Mei-Xiang Wang
Biomimicry of multiresponsive recognition of cell membrane with artificial membranes is challengeable. In this work, we designed azacalix[4]pyridine-based amphiphilic molecules 1 and 2. The self-assembly behaviors of 1 and 2 were investigated in aqueous medium. As demonstrated by DLS, SEM, TEM, and LSCM measurements, 1 formed stable vesicles (size 322 nm) in a mixture of THF/water, whereas 2 produced giant vesicles with decreased stability (size 928 nm). The vesicles composed of 1, with surface being engineered with the cavities of azacalix[4]pyridines, showed selective responses to a variety of guests including zinc ion, hydroquinone, and proton as monitored by DLS...
March 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28283893/tranexamic-acid-in-the-treatment-of-melasma-a-review-of-the-literature
#5
REVIEW
Marina Perper, Ariel Eva Eber, Rachel Fayne, Sebastian Hugo Verne, Robert James Magno, Jessica Cervantes, Mana ALharbi, Ibrahim ALOmair, Abdulkarem Alfuraih, Keyvan Nouri
Melasma is a common acquired pigmentary disorder marked by irregular hyperpigmented macules or patches and most commonly occurs in women of darker skin color. It is a chronic often-relapsing condition that causes negative psychosocial effects in those affected. Current treatments such as hydroquinone, kojic acid, and retinoids, among others, demonstrate variable efficacy and side-effect profiles. We conducted a comprehensive literature review examining the use of tranexamic acid (TA), a well-known anti-fibrinolytic agent, in the treatment of melasma...
March 10, 2017: American Journal of Clinical Dermatology
https://www.readbyqxmd.com/read/28282988/poly-p-hydroquinone-ethers-isoenergetic-molecular-wires-with-length-invariant-oxidation-potentials-and-cation-radical-excitation-energies
#6
Maxim V Ivanov, Vincent J Chebny, Marat R Talipov, Rajendra Rathore
Typical poly-p-phenylene wires are characterized by strong interchromophoric electronic coupling with redox and optical properties being highly length-dependent. Herein we show that an incorporation of a pair of para-methoxy groups at each p-phenylene unit in poly-p-phenylene wires (i.e. PHEn) changes the nodal structure of HOMO that leads to length-invariant oxidation potentials and cation radical excitation energies. As such, PHEn represents a unique class of isoenergetic wires where hole delocalization mainly occurs via dynamic hopping and thus may serve as an efficient medium for long-range charge transfer...
March 10, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28282572/performance-of-nitrogen-doped-graphene-aerogel-particle-electrodes-for-electro-catalytic-oxidation-of-simulated-bisphenol-a-wastewaters
#7
Zhuang Chen, Yimei Zhang, Lincheng Zhou, Hao Zhu, Fei Wan, Yue Wang, Dandan Zhang
The treatment of effluent containing Bisphenol A (BPA) was investigated experimentally using nitrogen-doped graphene aerogel (NGAs) as particle electrodes in a three-dimensional electrode reactor for the electrochemical treatment was studied. The effects of the cell voltage, pH, the ratio of NGAs mass to solution volume and repeated times on the removal efficiency were investigated. Compared with commercial carbon particle electrodes, the NGAs exhibited stronger activity to remove BPA simulated wastewater. For 15mgL(-1) of BPA solution, the degradation rate of BPA exceeded 90% after treatment for only 30min under the optimum conditions...
February 27, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28278779/phenol-abatement-using-persulfate-activated-by-nzvi-h2o2-and-naoh-and-development-of-a-kinetic-model-for-alkaline-activation
#8
Miguel A Lominchar, Sergio Rodríguez, David Lorenzo, Noelia Santos, Arturo Romero, Aurora Santos
Three persulfate (PS) activation methods (nanoparticles of zero-valent iron (nZVI), hydrogen peroxide and alkali) were compared using phenol as target pollutant. Firstly, four experiments were conducted at 25°C in a batch way using the same initial phenol and oxidant concentrations (10 mM and 420 mM, respectively), being the molar ratio activator/PS fixed to 0.005 with nZVI (mass ratio 0.0011 nZVI/PS), to 2 using hydrogen peroxide and to 2 and 4 with NaOH. Phenol and PS conversions and aromatic byproducts profiles during 168 h reaction time were measured and compared, as well as mineralization and ecotoxicity of the samples...
February 24, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28274417/photoelectrochemical-determination-of-tert-butylhydroquinone-in-edible-oil-samples-employing-cdse-zns-quantum-dots-and-litcne
#9
Thatyara Oliveira Monteiro, Auro Atsushi Tanaka, Flávio Santos Damos, Rita de Cássia Silva Luz
A novel photoelectrochemical sensor was developed for determination of tert-butyl-hydroquinone (TBHQ) in edible vegetable oils, based on CdSe/ZnS core-shell quantum dots sensitized with lithium tetracyanoethylenide (LiTCNE). The CdSe/ZnS/LiTCNE photoelectrochemical sensor presented a TBHQ photocurrent about 13-fold higher and a charge transfer resistance 62-fold lower than observed for a CdSe/ZnS sensor. The photoelectrochemical sensor showed selectivity to TBHQ, with a high photocurrent for this antioxidant compared to the photocurrent responses for other phenolic antioxidants...
July 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28264934/structure-activity-relationship-of-thapsigargin-inhibition-on-the-purified-golgi-secretory-pathway-ca2-mn2-transport-atpase-spca1a
#10
Jialin Chen, Joren De Raeymaecker, Jannik Brøndsted Hovgaard, Susanne Smaardijk, Ilse Vandecaetsbeek, Frank Wuytack, Jesper Vuust Møller, Jan Eggermont, Marc De Maeyer, Søren Brøgger Christensen, Peter Vangheluwe
The Golgi/secretory pathway Ca2+/Mn2+ transport ATPase (SPCA1a) is implicated in breast cancer and Hailey-Hailey disease. Here, we purified recombinant human SPCA1a from Saccharomyces cerevisiae and measured Ca2+ dependent ATPase activity following reconstitution in proteoliposomes. The purified SPCA1a displays a higher apparent Ca2+ affinity and lower maximal turnover rate than the purified sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1a). The lipids cholesteryl hemisuccinate, linole-/oleamide and phosphatidyl ethanolamine inhibit, whereas phosphatidic acid and sphingomyelin enhance SPCA1a activity...
March 6, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28263894/inhibition-of-autophagy-enhances-hydroquinone-induced-tk6-cell-death
#11
Longmei Xu, Jiaxian Liu, Yuting Chen, Lin Yun, Shaoyun Chen, Kairu Zhou, Bei Lai, Li Song, Hui Yang, Hairong Liang, Huanwen Tang
Hydroquinone (HQ), one of the metabolic products of benzene, is a carcinogen. It can induce apoptosis in lymphoma cells. However, whether HQ can induce autophagy and what roles autophagy plays in TK6 cells exposured to HQ remains unclear. In this study, we found that HQ could induce autophagy through techniques of qRT-PCR, Western blot, immunofluorescent assay of LC3 and transmission electron microscope. Furthermore, inhibiting autophagy using 3-methyladenine (3-MA) or chloroquine (CQ) significantly enhanced HQ-induced cell apoptosis, suggesting that autophagy may be a survival mechanism...
March 2, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28256650/synthesis-of-new-photosensitive-h2bbq-2-zncl4-2-zncl-2-%C3%AE-bbh-complexes-through-selective-oxidation-of-h2o-to-h2o2
#12
M Stylianou, I Hadjiadamou, C Drouza, S C Hayes, E Lariou, I Tantis, P Lianos, A C Tsipis, A D Keramidas
A new two-electron photosensitizer, H2BBQ(2+)[ZnCl4](2-)/[(ZnCl)2(μ-BBH)] (BBQ stands for 2,5-bis[bis(pyridin-2-ylmethyl)amino]-1,4-quinone and BBH stands for 2,5-bis[bis(pyridin-2-ylmethyl)amino]-1,4-hydroquinone), has been synthesized and the oxidation state of the ligand was determined by X-ray crystallography and NMR spectroscopy. Under light illumination the H2BBQ(2+)[ZnCl4](2-) + ZnCl2 is reduced quantitatively to [(ZnCl)2(μ-BBH)] (pH ∼ 5) oxidizing H2O to H2O2 as is evident by trap experiments. Electrochemistry gave a reversible two-electron ligand-centered redox wave for [(ZnCl)2(μ-BBH)]...
March 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28250317/strategic-drug-design-to-avoid-the-metabolic-activation-of-hepatotoxic-drugs
#13
Tomoyuki Ohe, Kyoko Takahashi, Shigeo Nakamura, Tadahiko Mashino
 Adverse reactions are one of the most important issues in drug development, as well as in the therapeutic usage of drugs during the post-approval stage. Specifically, idiosyncratic adverse drug reactions (IDR) occur in only a small group of patients who are treated with certain drugs, and are unpredictable. It is widely accepted that drug-induced IDR is often associated with CYP-mediated bioactivation. Benzbromarone (BBR) is effective in the treatment of hyperuricemia, and has been used as an effective drug in Japan for a long time...
2017: Yakugaku Zasshi: Journal of the Pharmaceutical Society of Japan
https://www.readbyqxmd.com/read/28243566/photocatalysis-applications-of-some-hybrid-polymeric-composites-incorporating-tio2-nanoparticles-and-their-combinations-with-sio2-fe2o3
#14
Andreea Laura Chibac, Tinca Buruiana, Violeta Melinte, Emil C Buruiana
Polymer nanocomposites containing titanium oxide nanoparticles (TiO2 NPs) combined with other inorganic components (Si-O-Si or/and γ-Fe2O3) were prepared by the dispersion of premade NPs (nanocrystalline TiO2, TiO2/SiO2, TiO2/Fe2O3, TiO2/SiO2/Fe2O3) within a photopolymerizable urethane dimethacrylate (polytetrahydrofuran-urethane dimethacrylate, PTHF-UDMA). The physicochemical characterization of nanoparticles and hybrid polymeric composites with 10 wt % NPs (S1-S4) was realized through XRD, TEM and FTIR analyses...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28242525/performance-robustness-of-the-uasb-reactors-treating-saline-phenolic-wastewater-and-analysis-of-microbial-community-structure
#15
Wei Wang, Benteng Wu, Shanglei Pan, Kai Yang, Zhenhu Hu, Shoujun Yuan
Anaerobic digestion was an important way to remove phenols from saline wastewater; however the anaerobic microorganisms were adversely affected by high concentration of salts. In order to clarify the performance robustness and microbial community structure for anaerobic digestion of saline phenolic wastewater, the UASB reactors were compared to treat phenolic wastewater under saline and non-saline conditions. The saline reactors were operated stably with phenols concentration increasing from 100 to 500mgL(-1) at 10g Na(+) L(-1)...
February 16, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28236333/on-the-way-to-a-trisanionic-cu3o2-core-for-oxidase-catalysis-evidence-of-an-asymmetric-trinuclear-precursor-stabilised-by-perfluoropinacolate-ligands
#16
Steven F Hannigan, Amanda I Arnoff, Sarah E Neville, June S Lum, James A Golen, Arnold L Rheingold, Nicole Orth, Ivana Ivanović-Burmazović, Patricia Liebhäuser, Thomas Rösener, Julia Stanek, Alexander Hoffmann, Sonja Herres-Pawlis, Linda H Doerrer
Cu(I) complexes of the form A[(R3P)Cu(pinF)] were synthesized and characterized, in which (pinF)2- is the bidentate, oxygen-donating, ligand perfluoropinacolate. Low temperature oxygenation of the A[(R3P)Cu(pinF)] species resulted in a trisanionic bis(μ3-oxo) trinuclear Cu(II,II,III) core that was characterized by UV-vis spectroscopy (λmax, nm (ε, M-1 cm-1)) = (330, 535 (19), 630 (33)), cryospray-ionization mass spectrometry (CSI-MS), and X-band electron paramagnetic resonance (EPR) spectroscopy (derivative resonance at 3300 G, Δms = 2 at 1500 G)...
February 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28215095/ph-dependence-of-photoinduced-electron-transfer-with-ru-tap-3-2
#17
Ludovic Troian-Gautier, Epiphanie Mugeniwabagara, Luca Fusaro, Cécile Moucheron, Andrée Kirsch-De Mesmaeker, Michel Luhmer
The quenching of the excited state of [Ru(TAP)3](2+) (TAP = 1,4,5,8-tetraazaphenanthrene) by guanosine-5'-monophosphate (GMP), N-acetyltyrosine (N-Ac-Tyr), and hydroquinone (H2Q) has been studied in aqueous solution over a wide range of pH values including, for the first time, strongly acidic media. This quenching by electron transfer was examined by steady-state (1)H photochemically induced dynamic nuclear polarization (photo-CIDNP) as well as by more conventional techniques, among which are pulsed laser-induced transient absorption and emission experiments...
February 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28212932/purification-and-characterisation-of-a-pronase-inducible-lectin-isolated-from-human-serum
#18
Beulaja Manikandan, Manikandan Ramar, Thiagarajan Raman, Mullainadhan Periasamy, Arumugam Munusamy
A new lectin was purified to electrophoretic homogeneity from pronase treated human serum by a single-step of affinity chromatography on concanavalin A-Sepharose 4B. The isolated lectin agglutinated five types of vertebrate RBC, with highest titer against hen RBC. This activity was independent of divalent cations, insensitive to EDTA and specific to mannosamine, glucosamine as well as galactosamine. Purified lectin gave a single symmetrical peak in its native form with a molecular mass estimate of 6kDa in FPLC analysis and 6...
February 14, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28211691/lipophilized-grape-seed-proanthocyanidin-derivatives-as-novel-antioxidants
#19
Mingshun Chen, Shujuan Yu
Grape seed proanthocyanidin (GSP) is a natural food antioxidant. Natural proanthocyanidins (PC) in grape seed are usually polyhydroxy derivatives which exhibit hydrophilic character. GSP was modified structurally to improve its lipophilicity, expand its application in lipophilic media, and enhance its cellular absorption in vivo. Esterification of the water-soluble GSP was prepared by immobilized lipase Lipozyme TL IM with lauric acid, and their enhanced lipophilicity was confirmed by the 1-octanol/water partition coefficient...
February 17, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28208259/ultrasensitive-electrochemical-detection-of-mirna-21-using-a-zinc-finger-protein-specific-to-dna-rna-hybrids
#20
Chiew San Fang, Kwang-Sun Kim, Byeongjun Yu, Sangyong Jon, Moon-Soo Kim, Haesik Yang
Both high sensitivity and high specificity are crucial for detection of miRNAs that have emerged as important clinical biomarkers. Just Another Zinc finger proteins (JAZ, ZNF346) bind preferably (but nonsequence-specifically) to DNA-RNA hybrids over single-stranded RNAs, single-stranded DNAs, and double-stranded DNAs. We present an ultrasensitive and highly specific electrochemical method for miRNA-21 detection based on the selective binding of JAZ to the DNA-RNA hybrid formed between a DNA capture probe and a target miRNA-21...
February 7, 2017: Analytical Chemistry
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