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Phosphoric acid

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https://www.readbyqxmd.com/read/29348095/estimation-of-simvastatin-and-cetirizine-by-rp-lc-method-application-to-freeze-and-thaw-ft-stability-studies
#1
Safila Naveed, Khan Usmanghani, Aisha Sana, Huma Ali, Farya Zafar, Fatima Qamar, Ghulam Sarwer, Sarah Abbas, M Tanweer Alam, Muhammad Ibrar Shinwari
Sensitive, simple, reliable and rapid HPLC technique for the estimation of simvastatin (SMV) and cetirizine has been designed in this study. The chromatographic conditions were set using Shimadzu LC-10 AT VP pump, with UV detector (SPD-10 AV-VP). System integration was performed with CBM-102 (Bus Module). Partitioning of components was attained with pre-packed C-18 column of Purospher Star (5 μm, 250 x 4.6 mm) at ambient conditions. Injected volume of sample was 10 μl. Mobile phase was composed of 50:50 v/v ratio of Acetonitrile/water (pH 3...
January 2018: Pakistan Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29347914/in-depth-proteomic-analysis-of-boar-spermatozoa-through-shotgun-and-gel-based-methods
#2
Jean M Feugang, Shengfa F Liao, Scott T Willard, Peter L Ryan
BACKGROUND: Mature spermatozoa contain numerous epididymal and seminal plasma proteins, which full identification through high-throughput technologies may allow for a better understanding of the sperm biology. Therefore, we conducted a global proteomic analysis of boar spermatozoa through shotgun and gel-based methodologies. RESULTS: The total proteins were extracted from mature spermatozoa and subjecsted to proteome analyses. Functional analyses of gene ontology representations and pathway enrichments were conducted on the shotgun dataset, followed by immunology and gene expression validations...
January 18, 2018: BMC Genomics
https://www.readbyqxmd.com/read/29345139/catalytically-enantioselective-synthesis-of-acyclic-%C3%AE-tertiary-amines-through-desymmetrization-of-2-substituted-2-nitro-1-3-diols
#3
Shan-Shui Meng, Wu-Bang Tang, Wen-Hua Zheng
Highly enantioselective synthesis of acyclic α-tertiary amines through asymmetric desymmetrization is reported. This approach is based on chiral phosphoric acid mediated, enantioselective, oxidative desymmetrization of 2-substituted 2-nitro-1,3-diolbenzylidine acetals in the presence of DMDO as an oxidant. The method allows for the formation of a wide variety of chiral 2-nitro-1,3-diols in high enantioselectivity, which could be transformed into optically pure, unnatural α-alkyl series. The synthetic utility of this method has been further demonstrated by the expedient construction of the core structure of natural products manzacidins enantioselectively...
January 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29344991/relationship-between-enamel-bond-fatigue-durability-and-surface-free-energy-characteristics-with-universal-adhesives
#4
Yuko Nagura, Akimasa Tsujimoto, Wayne W Barkmeier, Hidehiko Watanabe, William W Johnson, Toshiki Takamizawa, Mark A Latta, Masashi Miyazaki
The relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives was investigated. The initial shear bond strengths and shear fatigue strengths of five universal adhesives to enamel were determined with and without phosphoric acid pre-etching. The surface free-energy characteristics of adhesive-treated enamel with and without pre-etching were also determined. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were higher than those to ground enamel...
January 18, 2018: European Journal of Oral Sciences
https://www.readbyqxmd.com/read/29341624/regio-and-enantioselective-organocatalytic-friedel-crafts-alkylation-of-4-aminoindoles-at-the-c7-position
#5
Wen Xun, Bo Xu, Bo Chen, Shanshui Meng, Albert S C Chan, Fayang G Qiu, Junling Zhao
A chiral phosphoric acid catalyzed highly regio- and enantioselective Friedel-Crafts alkylation at the indole C7-position was developed via the introduction of an alkylamine moiety at the C4-position of the indole ring. The methodology is applicable to a wide range of 4-aminoindoles and β,γ-unsaturated α-ketimino esters to furnish the corresponding C7-position functionalized chiral indole derivatives in high yields with moderate to excellent enantioselectivities. Furthermore, the α-ketimino ester moiety in the products is a versatile building block and enables many further transformations...
January 17, 2018: Organic Letters
https://www.readbyqxmd.com/read/29339609/effects-of-ph-and-coexisting-chemicals-on-photolysis-of-perfluorooctane-sulfonate-using-an-excited-xenon-dimer-lamp
#6
Naoyuki Kishimoto, Koji Doda
Vacuum ultraviolet (VUV) photolysis at the wavelength of 172 nm in a sulfate solution was introduced as a more efficient process for perfluorooctane sulfonate (PFOS) degradation than ultraviolet (UV) photolysis at 254 nm. The effects of pH and coexisting chemicals on VUV photolysis under the coexistence of 100 mM sulfate were investigated. VUV irradiation successfully degraded PFOS, and the degradation rate was 5.5 times higher than by UV photolysis. Direct VUV photolysis was inferred to mainly contribute to PFOS degradation...
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29339280/simultaneous-degumming-and-production-of-a-natural-gum-from-crotalaria-juncea-seeds-physicochemical-and-rheological-characterization
#7
Suvra Sadhukhan, Annesha Bhattacharjee, Ujjaini Sarkar, Pabitra Kumar Baidya, Sibashish Baksi
The oil extracted from Crotalaria juncea (Sunn-hemp) contains 70% of gum. Several methods of degumming are attempted in order to maximize the yield of gum. During appropriate water induced degumming, about 95-98% of phosphatides are separated. The maximum oil yield for two types of degummimg processes are 0.59% and 0.69% corresponding to hot water and pure O-phosphoric acid (19.88 N) treatment respectively. The % oil yield obtained for TOP degumming is about 0.78%. Physico-chemical characteristics of the isolated gum such as moisture, ash, protein, fat and aqueous solubility along with FTIR and TGA analysis are studied in order to evaluate the effect of extraction process...
January 12, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29333771/-effect-of-hydrofluoric-acid-concentration-on-the-surface-morphology-and-bonding-effectiveness-of-lithium-disilicate-glass-ceramics-to-resin-composites
#8
Qian Hailan, Ren Lingyan, Nie Rongrong, Meng Xiangfeng
OBJECTIVE: This study aimed at determining the influence of hydrofluoric acid (HF) in varied concentrations on the surface morphology of lithium disilicate glass ceramics and bond durability between resin composites and post-treated lithium disilicate glass ceramics. METHODS: After being sintered, ground, and washed, 72 as-prepared specimens of lithium disilicate glass ceramics with dimensions of 11 mm×13 mm×2 mm were randomly divided into three groups. Each group was treated with acid solution [32% phosphoric acid (PA) or 4% or 9...
December 1, 2017: Hua Xi Kou Qiang Yi Xue za Zhi, Huaxi Kouqiang Yixue Zazhi, West China Journal of Stomatology
https://www.readbyqxmd.com/read/29328648/two-step-synthesis-and-surface-modification-of-caznos-mn2-phosphors-and-the-fabrication-of-a-luminescent-poly-dimethylsiloxane-film
#9
Zihan Xu, Zhiguo Xia, Quanlin Liu
The CaZnOS:Mn2+ (CZOSM) phosphor has been extensively studied for its excellent optical performance, with a typical red emission band peaking at about 580 nm ascribed to the 4T1(4G)-6A1(6S) transition of Mn2+. Herein the CZOSM phosphor was synthesized by a novel two-step method accompanied by control of the morphology of the precursor in the first step followed by sintering in the second step, which demonstrated improved emission intensity and uniform morphology simultaneously compared to those obtained by the traditional solid-state reaction route...
January 12, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29328519/surface-modification-using-the-biomimetic-method-in-alumina-zirconia-porous-ceramics-obtained-by-the-replica-method
#10
André D R Silva, Willian R Rigoli, Denise Osiro, Daphne C R Mello, Luana M R Vasconcellos, Anderson O Lobo, Eliria M J A Pallone
The modification of biomaterials approved by the Food and Drug Administration could be an alternative to reduce the period of use in humans. Porous bioceramics are widely used as support structures for bone formation and repair. This composite has essential characteristics for an implant, including good mechanical properties, high chemical stability, biocompatibility and adequate aesthetic appearance. Here, three-dimensional porous scaffolds of Al2 O3 containing 5% by volume of ZrO2 were produced by the replica method...
January 12, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29327453/catalytic-asymmetric-dearomatization-of-indolyl-dihydropyridines-via-enamine-isomerization-spirocyclization-transfer-hydrogenation-sequence
#11
Shuli You, Zi-Lei Xia, Chao Zheng, Shou-Guo Wang
A highly efficient synthesis of enantioenriched spiroindolines by catalytic asymmetric dearomatization of indolyl dihydropyridines via chiral phosphoric acid catalyzed enamine isomerization/spirocyclization/transfer hydrogenation sequence has been developed. This reaction proceeds under mild reaction conditions to afford novel spiroindolines in good yields (up to 88%) with excellent enantioselectivity (up to 97% ee). DFT calculations provide insights into the reaction mechanism as well as the origin of stereochemistry...
January 11, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29327089/comparative-efficacy-of-er-cr-ysgg-and-er-yag-lasers-for-etching-of-composite-for-orthodontic-bracket-bonding
#12
Amir Hossein Mirhashemi, Nasim Chiniforush, Nastaran Sharifi, Amir Mehdi Hosseini
Several techniques have been proposed to obtain a durable bond, and the efficacy of these techniques is assessed by measuring parameters such as bond strength. Laser has provided a bond strength as high as that of acid etching in vitro and has simpler use with shorter clinical time compared to acid etching. This study aimed to compare the efficacy of Er:YAG and Er,Cr:YSGG lasers for etching and bonding of composite to orthodontic brackets. No previous study has evaluated the effect of these particular types of laser...
January 11, 2018: Lasers in Medical Science
https://www.readbyqxmd.com/read/29326512/evaluating-the-effect-of-different-conditioning-agents-on-the-shear-bond-strength-of-resin-modified-glass-ionomers
#13
Namith Rai, Rajaram Naik, Ravi Gupta, Shobana Shetty, Amith Singh
Aim of the Study: This study aims to evaluate the effects three different conditioning agents on the shear bond strength of resin-modified glass ionomers to human dentin. Materials and Methods: One hundred and twenty recently extracted, caries-free premolars and molars will be cleaned of debris and disinfected in a 0.5% solution of sodium hypochlorite and sterile water for 30 min. The occlusal surface of each tooth will be reduced using conventional model trimmer with water to produce the dentin surface...
October 2017: Contemporary Clinical Dentistry
https://www.readbyqxmd.com/read/29323681/the-structure-of-a-lanthanide-complex-at-an-extractant-water-interface-studied-using-heterodyne-detected-vibrational-sum-frequency-generation
#14
Ryoji Kusaka, Masayuki Watanabe
Solvent extraction plays an integral part in the separation and purification of metals. Because extractants generally used as complexing agents for metal extractions, such as di-(2-ethylhexyl)phosphoric acid (HDEHP) for lanthanide extractions, are amphiphilic, they come to an organic/water interface, and the interface plays a crucial role as the site of the formation of metal complexes and the subsequent transfer reaction to an organic phase. Despite the importance of the interface for metal solvent extractions, its molecular-level structure is unclear because of the experimental difficulties...
January 11, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29314748/cyclotriphosphate-associated-to-fluoride-increases-hydroxyapatite-resistance-to-acid-attack
#15
Jackeline G Amaral, Juliano P Pessan, José Antonio S Souza, João Carlos S Moraes, Alberto Carlos B Delbem
This study evaluated the effect of sodium trimetaphosphate (TMP) associated or not with fluoride (F) on the structure and dissolution of carbonated hydroxyapatite (CHA). Synthetic CHA powder (1.0 g) was suspended in solutions containing TMP at 0-10%, associated with 0, 1100, 4500, or 9000 ppm F, and the precipitates were submitted to a pH cycle (n = 6/group). Samples were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. F, calcium (Ca) and phosphorous (P) concentrations were determined in CHA, while P and F were analyzed in the supernatants...
January 4, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29314546/palladium-catalyzed-enantioselective-desymmetrizing-aza-wacker-reaction-development-and-application-to-the-total-synthesis-of-mesembrane-and-crinane
#16
Xu Bao, Qian Wang, Jieping Zhu
We report in this paper an unprecedented catalytic enantioselective desymmetrizing aza-Wacker reaction. In the presence of a catalytic amount of newly developed Pd(CPA)2(MeCN)2 catalyst (CPA stands for chiral phosphoric acid), a pyrox ligand and molecular oxygen, cyclization of properly functionalized prochiral 3,3-disubstituted cyclohexa-1,4-dienes afforded enantioenriched cis-3a-substituted-tetrahydroindoles in good yields with excellent enantioselectivities. A cooperative effect between the phosphoric acid and the pyrox ligand ensured the efficient transformation...
January 3, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29309135/occurrence-and-phase-distribution-of-neutral-and-ionizable-per-and-polyfluoroalkyl-substances-pfass-in-the-atmosphere-and-plant-leaves-around-landfills-a-case-study-in-tianjin%C3%AF-china
#17
Ying Tian, Yiming Yao, Shuai Chang, Zhen Zhao, Yangyang Zhao, Xiaojia Yuan, Fengchang Wu, Hongwen Sun
A total of 23 per- and polyfluoroalkyl substances (PFASs) were investigated in the air, dry deposition, and plant leaves at two different landfills and one suburban reference site in Tianjin, China. The potential of landfills as sources of PFASs to the atmosphere and the phase distribution therein were evaluated. The maximum concentrations of ∑PFASs in the two landfills were up to 9.5 ng/m3 in the air, 4.1 μg/g in dry deposition, and 48 μg/g lipid in leaves with trifluoroacetic acid and perfluoropropionic acid being dominant (71%-94%)...
January 8, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29308808/alkaline-earth-be-mg-and-ca-bonds-at-the-origin-of-huge-acidity-enhancements
#18
M Merced Montero-Campillo, Pablo Sanz, Otilia Mó, Manuel Yáñez, Ibon Alkorta, José Elguero
The interaction between alkaline-earth derivatives with the general formula X2M (X = H, F and Cl; M = Be, Mg and Ca) and a set of Lewis bases, including first and second-row hydrides, namely YHn (Y = O, N, F, S, P and Cl) hydrides, as well as other typical cyclic organic bases, such as aniline, 1H-1,2,3-triazole, 1H-tetrazole and phenylphosphine, was investigated using the G4 ab initio composite method. Contrary to what was expected, it was found that the interactions involving Mg and Ca derivatives were not necessarily weaker than those between beryllium bonds...
January 8, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29307599/histone-deacetylase-inhibition-mediated-neuronal-differentiation-via-the-wnt-signaling-pathway-in-human-adipose-tissue-derived-mesenchymal-stem-cells
#19
Sujeong Jang, Han-Seong Jeong
Histone deacetylase (HDAC) inhibitors, which have an effect on cell homeostasis, cell cycle progression, and terminal differentiation, can act to promote self-renewal and enhance directed differentiation of several lineages of stem cells. However, the roles of HDAC inhibitors on neurogenic differentiation and the mechanisms of Wnt signaling following treatment with HDAC inhibitors remain unclear in stem cells. We hypothesized that HDAC inhibitors regulate downstream Wnt signaling and neurogenic differentiation of mesenchymal stem cells...
January 4, 2018: Neuroscience Letters
https://www.readbyqxmd.com/read/29301332/arsenic-uptake-toxicity-detoxification-and-speciation-in-plants-physiological-biochemical-and-molecular-aspects
#20
REVIEW
Ghulam Abbas, Behzad Murtaza, Irshad Bibi, Muhammad Shahid, Nabeel Khan Niazi, Muhammad Imran Khan, Muhammad Amjad, Munawar Hussain
Environmental contamination with arsenic (As) is a global environmental, agricultural and health issue due to the highly toxic and carcinogenic nature of As. Exposure of plants to As, even at very low concentration, can cause many morphological, physiological, and biochemical changes. The recent research on As in the soil-plant system indicates that As toxicity to plants varies with its speciation in plants (e.g., arsenite, As(III); arsenate, As(V)), with the type of plant species, and with other soil factors controlling As accumulation in plants...
January 2, 2018: International Journal of Environmental Research and Public Health
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