bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of Contiguous Quaternary and Tertiary Stereocenters by Sequential Asymmetric Conjugate Addition of Grignard Reagents to 2‐Substituted Enones and Mg–Enolate Trapping
Authors: Germain Nicolas , Alexakis Alexandre 
Published: April 2015

AbstractHerein a comprehensive study is provided on the asymmetric conjugate addition (ACA) of Grignard reagents to α‐substituted cyclic enones. After the elucidation of the optimal experimental conditions, the scope of Grignard reagents and Michael acceptors was examined. Whereas secondary Grignards gave better enantioselectivities with 2‐cyclopentenones, both linear and branched Grignard reagents were tolerated for the ACA to 2‐methylcyclohexenone. The sequential ACA–enolate trapping, which leads to quaternary stereocenters, was then studied. Thus, many electrophiles have been tested, thereby giving rise to highly functionalized cyclic ketones with contiguous α‐quaternary and β‐tertiary centers. The present technique is believed to bring a new approach to versatile terpenoid‐like skeletons of bioactive natural products. Straightforward derivatizations of enantioenriched saturated cyclic ketones further support the potential of the present methodology in synthesis.
The 6,6‐Dicyanopentafulvene Core: A Template for the Design of Electron‐Acceptor Compounds
Authors: Finke Aaron D. , Jahn Burkhard O. , Saithalavi Anas , Dahlstrand Christian , Nauroozi Djawed , Haberland Sophie , Gisselbrecht Jean‐Paul , Boudon Corinne , Mijangos Edgar , Schweizer W. Bernd , Ott Sascha , Ottosson Henrik , Diederich François 
Published: April 2015

AbstractThe electron‐accepting ability of 6,6‐dicyanopentafulvenes (DCFs) can be varied extensively through substitution on the five‐membered ring. The reduction potentials for a set of 2,3,4,5‐tetraphenyl‐substituted DCFs, with varying substituents at the para‐position of the phenyl rings, strongly correlate with their Hammett σp‐parameters. By combining cyclic voltammetry with DFT calculations ((U)B3LYP/6‐311+G(d)), using the conductor‐like polarizable continuum model (CPCM) for implicit solvation, the absolute reduction potentials of a set of twenty DCFs were reproduced with a mean absolute deviation of 0.10 eV and a maximum deviation of 0.19 eV. Our experimentally investigated DCFs have reduction potentials within 3.67–4.41 eV, however, the computations reveal that DCFs with experimental reduction potentials as high as 5.3 eV could be achieved, higher than that of F4‐TCNQ (5.02 eV). Thus, the DCF core is a template that allows variation in the reduction potentials by about 1.6 eV.
A Visible Light Photocatalytic Cross‐Dehydrogenative Coupling/Dehydrogenation/6π‐Cyclization/Oxidation Cascade: Synthesis of 12‐Nitroindoloisoquinolines from 2‐Aryltetrahydroisoquinolines
Authors: Rusch Fabian , Unkel Lisa‐Natascha , Alpers Dirk , Hoffmann Frank , Brasholz Malte 
Published: April 2015

AbstractA visible light‐induced photocatalytic dehydrogenation/6π‐cyclization/oxidation cascade converts 1‐(nitromethyl)‐2‐aryl‐1,2,3,4‐tetrahydroisoquinolines into novel 12‐nitro‐substituted tetracyclic indolo[2,1‐a]isoquinoline derivatives. Various photocatalysts promote the reaction in the presence of air and a base, the most efficient being 1‐aminoanthraquinone in combination with K3PO4. Further, the 12‐nitroindoloisoquinoline products can be accessed directly from C1‐unfunctionalized 2‐aryl‐1,2,3,4‐tetrahydroisoquinolines by extending the one‐pot protocol with a foregoing photocatalytic cross‐dehydrogenative coupling reaction, resulting in a quadruple cascade transformation.
Titanium Dioxide/Graphene Oxide Nanocomposites as Heterogeneous Catalysts for the Esterification of Benzoic Acid with Dimethyl Carbonate
Authors: Josephine Durairaj Santhakumar Ruby , Sakthivel Balasubramanian , Sethuraman Kunjithapatham , Dhakshinamoorthy Amarajothi 
Published: April 2015

AbstractGraphene oxide (GO) was prepared by modified Hummers' method starting from commercially available graphite. Different amounts of titanium dioxide nanoparticles (TiO2) were loaded on the sheets of GO to obtain titanium dioxide/graphene oxide (TiO2/GO) nanocomposites. The as‐synthesized 5 wt % TiO2/GO nanocomposite was characterized by UV/Vis spectroscopy, photoluminescence spectroscopy, FTIR, powder X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy techniques. The catalytic activity of the 5 wt % TiO2/GO nanocomposite was evaluated in the esterification of benzoic acid using dimethyl carbonate (DMC) as a green methylating agent. Furthermore, the activity of this nanocomposite for the conversion of benzoic acid was higher than that of the parent GO, TiO2, TiO2/activated carbon, and TiO2/graphite.
Peculiar Properties of Mesoporous Synthetic Carbon/Graphene Phase Composites and their Effect on Supercapacitive Performance
Authors: Seredych Mykola , Rodríguez‐Castellón Enrique , Bandosz Teresa J. 
Published: April 2015

AbstractComposites of mesoporous synthetic carbon and the graphene phase were synthesized in aqueous suspension by employing dispersive interactions of both phases. The resulting carbon‐based materials were further heat treated in air at 350 °C. The composites and their components were characterized by using adsorption of nitrogen, potentiometric titration, thermal analysis–mass spectrometry, X‐ray photoelectron spectroscopy, SEM, high‐resolution TEM, and XRD. Then, they were tested as supercapacitors in three‐electrode cells and under visible‐light irradiation. The composites and the initial carbon share exactly the same pore‐size distributions, but they exhibit significant differences in their surface chemistry, wettability, and conductivity. This allowed us to determine the extent of their effects on their capacitive/pseudocapacitive performance. The results showed that features other than the textural properties can increase the capacitive performance by more than 100 %. The synergistic properties of the composites and their sulfur functional group related photoactivity were linked to chemical interactions between the nanoporous carbon phase and graphite oxide during the formation of the composite.
Promoting Effect of Sodium Chloride on the Solubilization and Depolymerization of Cellulose from Raw Biomass Materials in Water
Authors: Jiang Zhicheng , Yi Jian , Li Jianmei , He Ting , Hu Changwei 
Published: April 2015

AbstractThe development of a green system to solubilize cellulose from raw biomass is important, yet it is challenging because of the insolubility of cellulose in most solvents. Herein, a green NaCl‐H2O system is developed in which NaCl significantly enhances the dissolution and depolymerisation of cellulose from raw biomass. Nearly all the cellulose in the selected biomass types was dissolved and degraded into oligomers with molecular weights of 200–400 Da under relatively mild conditions. Cl− could interact strongly with the end OH group of the glucose unit in a 1:1 ratio, which resulted in the enhanced breaking of both inter‐ and intramolecular hydrogen bonds. In particular, the intermolecular hydrogen bond with an FTIR band at approximately =3200 cm−1 was disrupted significantly by Cl−. The FTIR band for a hydrogen bond between hemicellulose and lignin might appear at =1636 cm−1, whereas this bond could be almost totally broken under hydrothermal conditions at 220 °C.
Carbonylation of Hydrido–Phosphanido‐Bridged Dinuclear Platinum Complexes
Authors: Latronico Mario , Mastrorilli Piero , Gallo Vito , Todisco Stefano , Dell'Anna Maria Michela , Rizzuti Antonino 
Published: April 2015

AbstractThe carbonylation of the solvento species [(PHCy2)(L)Pt(μ‐PCy2)(μ‐H)Pt(PHCy2){κP‐P(OH)Cy2}][BF4]2(Pt–Pt) ([1‐L]2+, L = CH2Cl2, thf, CH3CN) led to the formation of a singly bridged dicarbonyl PtI compound syn‐[(PHCy2)(CO)Pt(μ‐PCy2)Pt{κP‐P(OH)Cy2}(CO)]+(Pt–Pt) (2+). The reaction proceeded in two steps: 1) Substitution of L by CO to give the intermediate syn‐[(PHCy2)(CO)Pt(μ‐PCy2)(μ‐H)Pt(PHCy2){κP‐P(OH)Cy2}]2+(Pt–Pt) ([1‐CO]2+) and 2) uptake of a second molecule of CO and elimination of [PH2Cy2]+ (as the BF4– salt) to give 2+. The dicarbonyl complex [2][BF4] was also synthesized starting from the dicyclohexylphosphanido‐bridged complex [(PHCy2)Pt(μ‐PCy2){κ2P,O‐μ‐P(O)Cy2}Pt(PHCy2)](Pt–Pt) (5). In this case the first step consisted of the carbonylation of 5 to give [(PHCy2)2Pt(μ‐PCy2)Pt{κP‐P(O)Cy2}(CO)](Pt–Pt) (6), which was transformed into 2+ by protonation with HBF4 under an atmosphere of CO. Prolonged reaction times for the carbonylation of [1‐L]2+ in halogenated solvents resulted in the formation of the symmetrical dicarbonyl compound syn‐[(CO)(PHCy2)Pt(μ‐PCy2)Pt(PHCy2)(CO)]+(Pt–Pt) (3+) along with Cy2P(H)OBF3. Complexes 6 and [1‐L][BF4]2 were also formed by the carbonylation of 5 and [1‐OMe2][BF4]2 in the solid state.
Isotherm, kinetic, and thermodynamic studies on Ni(II) removal from aqueous solution by Citrus limettioides seed and its carbon derivative
Authors: Ramasamy Sudha , Krishnamoorthy Srinivasan 
Published: April 2015

Activated carbon was prepared from Citrus limettioides seed (CLSC), a novel waste material by chemical modification with sulfuric acid was applied for the adsorption Ni(II) from aqueous solutions. The effect of contact time, pH, adsorbent dose, initial metal ion concentration, and temperature were studied in batch experiments. According to the experimental results, the equilibrium time, optimum pH range, and adsorbent dosage were found to be 3 h, pH = 4.0–8.0 and 1 g L−1, respectively. In addition, raw Citrus limettioides seeds (CLS) were used as adsorbents at the same parameters. Ni(II) removal for CLSC and CLS were obtained 99.00% and 37.00% in turn. The equilibrium data agreed well with Langmuir model, which confirmed the monolayer coverage of Ni(II) ions onto CLS and CLSC. The Langmuir monolayer adsorption capacity of the CLSC was found to be 36.06 mg g−1 which was significantly about 3.5 times greater than that of CLS (10.23 mg g−1) at 300 K. The kinetic data followed pseudo‐second order model and intra‐particle diffusion was not the sole rate‐controlling factor. Surface morphology and structural analysis of CLSC prior to and after adsorption were characterized by SEM and EDX. The presence of hydroxyl, carboxylic, and sulfonic acid groups are confirmed by FTIR spectra. The adsorbents were also tested for the removal of Ni(II) from electroplating wastewater in connection with the reuse and selectivity of the adsorbents. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1384–1395, 2015
Observed and modeled effects of pH on bioconcentration of diphenhydramine, a weakly basic pharmaceutical, in fathead minnows
Authors: Nichols John W. , Du‌ Bowen , Berninger‌ Jason P. , Connors Kristin A. , Chambliss‌ C.Kevin , Erickson Russell J. , Hoffman Alex D. , Brooks Bryan W. 
Published: April 2015

Abstract

A need exists to better understand the influence of pH on the uptake and accumulation of ionizable pharmaceuticals in fish. In the present study, fathead minnows were exposed to diphenhydramine (DPH; disassociation constant = 9.1) in water for up to 96 h at 3 nominal pH levels: 6.7, 7.7, and 8.7. In each case, an apparent steady state was reached by 24 h, allowing for direct determination of the bioconcentration factor (BCF), blood–water partitioning (PBW,TOT), and apparent volume of distribution (approximated from the whole-body–plasma concentration ratio). The BCFs and measured PBW,TOT values increased in a nonlinear manner with pH, whereas the volume of distribution remained constant, averaging 3.0 L/kg. The data were then simulated using a model that accounts for acidification of the gill surface caused by elimination of metabolically produced acid. Good agreement between model simulations and measured data was obtained for all tests by assuming that plasma binding of ionized DPH is 16% that of the neutral form. A simpler model, which ignores elimination of metabolically produced acid, performed less well. These findings suggest that pH effects on accumulation of ionizable compounds in fish are best described using a model that accounts for acidification of the gill surface. Moreover, measured plasma binding and volume of distribution data for humans, determined during drug development, may have considerable value for predicting chemical binding behavior in fish. Environ Toxicol Chem 2015;34:1425–1435. © 2015 SETAC
Dynamic frame aggregation scheduler for multimedia applications in IEEE 802.11n networks
Authors: Charfi Emna , Gueguen Cédric , Chaari Lamia , Cousin Bernad , Kamoun Lotfi 
Published: April 2015

AbstractProviding quality of service (QoS) for real time applications over wireless local area networks is becoming a very challenging task due to the diversity of multimedia applications. Concurrently, there are numerous wireless local area networks WLAN(s) devices that are rising today. In the current paper, we focus on Institute of Electrical and Electronics Engineers (IEEE) 802.11n because it was designed to support a high data transmission rate (towards 600 Mbps). It is based on frame aggregation schemes that accumulate many subframes to be transmitted into a single larger frame. Thus overheads are reduced, efficiency and throughput are improved. However, it increases delay particularly for low rate applications. In fact, when the queue is empty, the medium access control layer (MAC) has to wait other packets to arrive in the queue to construct the whole aggregated frame. Moreover, if flows are not served, they will be accumulated in the queue causing an increased delay. To overcome these limitations, we propose a new dynamic frame aggregation (DFA) scheduler to provide QoS satisfaction to real time services. DFA schedules flows based on urgency delay and waiting delay, then it dynamically adjusts the payload size of aggregated frame. Conducted simulations prove that the proposed DFA scheduler provides QoS delay and throughput guarantee, and it reduces the number of dropped packets. Copyright © 2015 John Wiley & Sons, Ltd.
Salivary duct carcinoma: Treatment, outcomes, and patterns of failure
Authors: Johnston Meredith L. , Huang Shao Hui , Waldron John N. , Atenafu Eshetu G. , Chan Kelvin , Cummings Bernard J. , Gilbert Ralph W. , Goldstein David , Gullane Patrick J. , Irish Jonathan C. , Perez–Ordonez Bayardo , Weinreb Ilan , Bayley Andrew , Cho John , Dawson Laura A. , Hope Andrew , Ringash Jolie , Witterick Ian J. , O'Sullivan Brian , Kim John 
Published: April 2015

AbstractBackgroundSalivary duct carcinoma is rare, with distinct morphology and behavior. We reviewed our institutional experience with salivary duct carcinoma, aiming to characterize clinical behavior and treatment outcomes.MethodsAll salivary duct carcinomas treated curatively between 1999 and 2010 were reviewed. Overall survival (OS), locoregional control, distant control, and patterns of failure were analyzed. Multivariate analysis identified predictors of OS.ResultsFifty‐four patients with salivary duct carcinoma (parotid gland = 49; submandibular gland = 5) were included in the analysis. Fifty‐three patients underwent primary surgery, and 48 (89%) received postoperative radiotherapy (RT; median dose = 60 Gy). Median follow‐up was 5.7 years. The 5‐year OS, locoregional control, and distant control were 43%, 70%, and 48%, respectively. Nine local (6 involving facial nerve), 10 regional, and 28 distant failures were identified. Multiple pathologic involved lymph nodes (pN2b/N2c) predicted reduced OS (hazard ratio [HR] = 3.6; p = .02).ConclusionDistant recurrence is common. Presence of pN2b/N2c disease is associated with reduced OS. Local recurrence frequently involves the facial nerves. © 2015 Wiley Periodicals, Inc. Head Neck 38: E820–E826, 2016
Significance of mammalian target of rapamycin in patients with locally advanced stage IV head and neck squamous cell carcinoma receiving induction chemotherapy with docetaxel, cisplatin, and fluorouracil
Authors: Li Shau‐Hsuan , Lin Wei‐Che , Huang Tai‐Lin , Chen Chang‐Han , Chiu Tai‐Jan , Fang Fu‐Min , Huang Wan‐Ting , Hsu Cheng‐Ming , Luo Sheng‐Dean , Lai Chi‐Chih , Su Yan‐Ye , Chuang Hui‐Ching , Chien Chih‐Yen 
Published: April 2015

AbstractBackgroundThis study evaluated the significance of mammalian target of rapamycin (mTOR) activation on the prognosis of patients with locally advanced head and neck squamous cell carcinoma (HNSCC) receiving induction chemotherapy with docetaxel, cisplatin, and fluorouracil (TPF).MethodsImmunohistochemistry (IHC) for phosphorylated‐mTOR and phosphorylated‐p70 ribosomal S6 protein kinase (p70S6K) examined in 107 patients with locally advanced HNSCC receiving TPF was correlated with treatment outcome. The effect of mTOR inhibition on HNSCC cell lines was investigated in vitro and in vivo.ResultsPhosphorylated‐mTOR expression was independently significantly associated with response to TPF, progression‐free survival (PFS), and overall survival (OS). In cell lines and xenograft models, mTOR inhibitor, everolimus, enhanced the effect of docetaxel.ConclusionIn patients with locally advanced HNSCC treated with TPF, phosphorylated‐mTOR expression was independently associated with prognosis. In vitro and in vivo, concomitant inhibition of mTOR enhanced the effect of docetaxel. Our findings suggest the potential of mTOR as a therapeutic target for locally advanced HNSCC. © 2015 Wiley Periodicals, Inc. Head Neck 38: E844–E852, 2016
Clinical characteristics and treatment outcomes of primary and recurrent malignancy involving the salivary glands in children
Authors: Qureshi Sajid S. , Bhagat Monica , Singhal Nitin , Tathe Nitin , Kembhavi Seema , Laskar Siddharth , Ramadwar Mukta , Yadav Prabha 
Published: April 2015

AbstractBackgroundMalignant salivary gland neoplasms are rare in children. The purpose of this study was to present our experience in the treatment of primary and recurrent salivary gland neoplasm and contribute to the fractional available data.MethodsAll patients <18 years, treated between June 2005 and April 2014 were included in this study.ResultsThe parotid gland was the most common site for both primary (n = 18) and recurrent (n = 6) tumors and mucoepidermoid carcinoma, low or intermediate grade, main histological type. Surgical excision was performed in all patients, of which 13 patients received radiotherapy. Lymph node metastasis was present in 3 patients with primary tumor, which were assessed accurately on frozen section examination. Local recurrence occurred in 1 patient with primary tumor and all patients are alive.ConclusionSurgery is the prime modality of treatment for malignant salivary gland neoplasm and is associated with excellent outcomes. The role of lymph node sampling and frozen section examination needs further evaluation in identifying lymph node metastasis. © 2015 Wiley Periodicals, Inc. Head Neck 38: 852–856, 2016
Purification and Characterization of a New Serine Protease (VLCII) Isolated from Vipera lebetina Venom: Its Role in Hemostasis
Authors: Amel Kadi‐Saci , Fatima Laraba‐Djebari 
Published: April 2015

ABSTRACTSnake venom serine proteinases (SVSPs) affect various physiological functions including blood coagulation, fibrinolysis, and platelet aggregation. Coagulant serine proteinase (VLCII) was purified from Vipera lebetina venom using three chromatographic steps: gel filtration on SephadexG‐75, DEAE‐Sephadex A‐50, and reversed‐phase high‐performance liquid chromatography (RP‐HPLC) on C8 column. VLCII appeared homogenous (60 kDa) when tested on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). VLCII as a thrombin‐like enzyme was able to hydrolyze Nα‐CBZ L‐arginine‐p‐nitroanilide hydrochloride and could be a serine protease because it is inhibited by phenylmethylsulfonyl fluoride. The proteolytic activity of VLCII was not affected by ethylenediaminetetraacetic acid and 1.10‐phenanthroline. It showed high coagulant activity against human plasma and cleaved both Aα chain and Bβ chain of bovine fibrinogen. The isolated VLCII displayed proaggregating effect on human platelet in a concentration‐dependent manner with an absence of lag time. Clopidogrel P2Y12 adenosine diphosphate (ADP) receptor inhibitor reduced markedly the aggregating effect induced by VLCII than aspirin, indicating the involvement of ADP signaling pathway.
Atorvastatin Increases miR‐124a Expression: A Mechanism of Gamt Modulation in Liver Cells
Authors: Phulukdaree Alisa , Moodley Devapregasan , Khan Sajidah , Chuturgoon Anil A. 
Published: April 2015

ABSTRACTAtorvastatin is used to control cholesterol and lipid levels in hyperlipidaemic and hypercholesterolaemic patients. Myopathy and hepatotoxicity, however, have been reported as side effects in a small percentage of statin users. This study aimed to investigate the cytotoxicity and the effect of atorvastatin on microRNA expression in HepG2 cells. The methylthiazol tetrazolium assay was used to assess hepatocyte viability and at 20 μM atorvastatin (24 h) treatment were 82 ± 1.5% viable (P = 0.0002). Levels of intracellular ATP in cells treated with 20 μM atorvastatin were reduced by 1.25‐fold, P = 0.002. Cytotoxicity, measured by the release of intracellular lactate dehydrogenase, was increased from 0.95 ± 0.29 units in control cells to 1.12 ± 0.02 units (P = 0.002) in atorvastatin treated cells. A panel of 84‐miRNA species was used to evaluate the effect of atorvastatin on miRNA expression. MiR‐124a was significantly up‐regulated by atorvastatin (12.94‐fold). A significant decrease in GAMT expression (3.54‐fold) was observed in atorvastatin treated cells following quantitative PCR analysis. In addition, western blotting data showed GAMT protein levels were significantly lower than the controls (3.02‐fold) and analysis of creatine levels in treated cells showed a significant decrease in the atorvastatin treated culture supernatant compared to control culture supernatant (32.33 ± 3.51 μM/l vs. 59.67 ± 1.52μM/l, P = 0.0056). This is the first study to show that atorvastatin up‐regulates miR‐124a levels and consequently modulates GAMT expression in hepatocytes. J. Cell. Biochem. 116: 2620–2627, 2015. © 2015 Wiley Periodicals, Inc.
Histone Demethylase Utx Regulates Differentiation and Mineralization in Osteoblasts
Authors: Yang Di , Okamura Hirohiko , Teramachi Jumpei , Haneji Tatsuji 
Published: April 2015

ABSTRACTAlteration of methylation status of lysine 27 on histone H3 (H3K27) associates with dramatic changes in gene expression in response to various differentiation signals. Demethylation of H3K27 is controlled by specific histone demethylases including ubiquitously transcribed tetratricopeptide repeat X chromosome (Utx). However, the role of Utx in osteoblast differentiation remains unknown. In this study, we examined whether Utx should be involved in osteoblast differentiation. Expression of Utx increased during osteoblast differentiation in MC3T3‐E1 cells and primary osteoblasts. GSK‐J1, a potent inhibitor of H3K27 demethylase, increased the levels of trimethylated H3K27 (H3K27me3) and decreased the expressions of Runx2 and Osterix and ALP activity in MC3T3‐E1 cells. Stable knockdown of Utx by shRNA attenuated osteoblast differentiation and decreased ALP activity, calcium content, and bone‐related gene expressions. Silencing of Utx increased the level of H3K27me3 on the promoter regions of Runx2 and Osterix and decreased the promoter activities of Runx2 and Osterix. Taken together, our present results propose that Utx plays important roles in osteoblast differentiation by controlling the expressions of Runx2 and Osterix. J. Cell. Biochem. 116: 2628–2636, 2015. © 2015 Wiley Periodicals, Inc.