bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoluminescence shift in frustules of two pennate diatoms and nanostructural changes to their pores
Authors: Arteaga‐Larios Nubia V. , Nahmad Yuri , Navarro‐Contreras Hugo R. , Encinas Armando , Viridiana García‐Meza J. 
Published: March 2014

ABSTRACTThe diatom silicified cell wall (frustule) contains pore arrays at the micro‐ to nanometer scale that display efficient luminescence within the visible spectrum. Morphometric analysis of the size and arrangement of pores was conducted to observe whether any correlation exists with the photoluminescence (PL) of two diatom species of different ages. UV‐excited PL displays four clearly defined peaks within the blue‐region spectrum, on top of the broad PL characteristic of synthetic porous silicon dioxide, recorded for reference and where discrete lines are absent. A set of shifted emission lines was observed when diatom cultures reached adulthood. These discrete line shifts correlate with structural changes observed in adult frustules: reduction in pore diameter; appearance of pores within pores, 10 nm in size; an increase in the gap distance between stria; and the deposition of several girdle bands with a concomitant increase in the diatom waist length, as well as the appearance of pores on such bands. Destruction of the pores results in the disappearance of all discrete emission lines. The PL shifts are correlated with a substantial increment of Si–OH groups adsorbed on the frustule surface, as revealed by Fourier transform infrared spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.
Randomized two‐way cross‐over bioequivalence study of two amoxicillin formulations and inter‐ethnicity pharmacokinetic variation in healthy Malay volunteers
Authors: Liew Kai Bin , Loh Gabriel Onn Kit , Tan Yvonne Tze Fung , Peh Kok Khiang 
Published: March 2014

ABSTRACTThe objectives of this study were to develop a new deproteinization method to extract amoxicillin from human plasma and evaluate the inter‐ethnic variation of amoxicillin pharmacokinetics in healthy Malay volunteers. A single‐dose, randomized, fasting, two‐period, two‐treatment, two‐sequence crossover, open‐label bioequivalence study was conducted in 18 healthy Malay adult male volunteers, with one week washout period. The drug concentration in the sample was analyzed using high‐performance liquid chromatography (UV–vis HPLC). The mean (standard deviation) pharmacokinetic parameter results of Moxilen® were: peak concentration (Cmax), 6.72 (1.56) µg/mL; area under the concentration–time graph (AUC0–8), 17.79 (4.29) µg/mL h; AUC0–∞, 18.84 (4.62) µg/mL h. Those of YSP Amoxicillin® capsule were: Cmax, 6.69 (1.44) µg/mL; AUC0–8, 18.69 (3.78) µg/mL h; AUC00–∞, 19.95 (3.81) µg/mL h. The 90% confidence intervals for the logarithmic transformed Cmax, AUC0–8 and AUC0–∞ of Moxilen® vs YSP Amoxicillin® capsule was between 0.80 and 1.25. Both Cmax and AUC met the predetermined criteria for assuming bioequivalence. Both formulations were well tolerated. The results showed significant inter‐ethnicity variation in pharmacokinetics of amoxicillin. The Cmax and AUC of amoxicillin in Malay population were slightly lower compared with other populations. Copyright © 2014 John Wiley & Sons, Ltd.
Comparative study on effects of single and multiple oral administration of mungbean (Phaseolus radiatus L.) seed extract on the pharmacokinetics of aconitine by UHPLC‐MS
Authors: Gao Enze , Yu Xiaohan , Liu Ting , Li Hualing , Wang Pei , Wei Yingqing , Zhao Yunli , Yu Zhiguo 
Published: March 2014

ABSTRACTThe study was aimed to investigate the effects of single and multiple oral administration of mungbean (Phaseolus radiatus L.) seed extract (ME) on the pharmacokinetics of aconitine in rats. The Sprague–Dawley rats were randomly divided into three groups (six rats each group). In group 1, rats were orally administered 500 µg/kg aconitine after receiving a single oral dose of 1 g/kg ME. In group 2, rats were orally administered with 500 µg/kg aconitine at day 7 of treatment with 1 g/kg/day ME. In group 3, rats were orally administered with 500 µg/kg aconitine. Blood samples were collected at different time points (0.083, 0.25, 0.5, 1.0, 1.5, 2.0, 4.0, 6.0, 8.0 and 10.0 h). The concentration of aconitine in rats plasma was determined by a fully validated ultra‐high‐performance liquid chromatography coupled with mass spectrometry method. The results showed that single and multiple oral co‐administration of ME significantly altered the pharmacokinetic parameters of aconitine. Copyright © 2014 John Wiley & Sons, Ltd.
Significant SNPs have limited prediction ability for thyroid cancer
Authors: Guo Shicheng , Wang Yu‐Long , Li Yi , Jin Li , Xiong Momiao , Ji Qing‐Hai , Wang Jiucun 
Published: March 2014

AbstractRecently, five thyroid cancer significantly associated genetic variants (rs965513, rs944289, rs116909374, rs966423, and rs2439302) have been discovered and validated in two independent GWAS and numerous case–control studies, which were conducted in different populations. We genotyped the above five single nucleotide polymorphisms (SNPs) in Han Chinese populations and performed thyroid cancer‐risk predictions with nine machine learning methods. We found that four SNPs were significantly associated with thyroid cancer in Han Chinese population, while no polymorphism was observed for rs116909374. Small familial relative risks (1.02–1.05) and limited power to predict thyroid cancer (AUCs: 0.54–0.60) indicate limited clinical potential. Four significant SNPs have limited prediction ability for thyroid cancer.
Long noncoding RNA HOTAIR is relevant to cellular proliferation, invasiveness, and clinical relapse in small‐cell lung cancer
Authors: Ono Hiroshi , Motoi Noriko , Nagano Hiroko , Miyauchi Eisaku , Ushijima Masaru , Matsuura Masaaki , Okumura Sakae , Nishio Makoto , Hirose Tetsuro , Inase Naohiko , Ishikawa Yuichi 
Published: March 2014

AbstractSmall‐cell lung cancer (SCLC) is a subtype of lung cancer with poor prognosis. To identify accurate predictive biomarkers and effective therapeutic modalities, we focus on a long noncoding RNA, Hox transcript antisense intergenic RNA (HOTAIR), and investigated its expression, cellular functions, and clinical relevance in SCLC. In this study, HOTAIR expression was assessed in 35 surgical SCLC samples and 10 SCLC cell lines. The efficacy of knockdown of HOTAIR by siRNA transfection was evaluated in SBC‐3 cells in vitro, and the gene expression was analyzed using microarray. HOTAIR was expressed highly in pure, rather than combined, SCLC (P = 0.012), that the subgroup with high expression had significantly more pure SCLC (P = 0.04), more lymphatic invasion (P = 0.03) and more relapse (P = 0.04) than the low‐expression subgroup. The knockdown of HOTAIR in SBC‐3 cells led to decreased proliferation activity and decreased invasiveness in vitro. Gene expression analysis indicated that depletion of HOTAIR resulted in upregulation of cell adhesion‐related genes such as ASTN1, PCDHA1, and mucin production‐related genes such as MUC5AC, and downregulation of genes involved in neuronal growth and signal transduction including NTM and PTK2B. Our results suggest that HOTAIR has an oncogenic role in SCLC and could be a prognostic biomarker and therapeutic target.
Grassypeptolides as Natural Inhibitors of Dipeptidyl Peptidase 8 and T‐Cell Activation
Authors: Kwan Jason C. , Liu Yanxia , Ratnayake Ranjala , Hatano Ryo , Kuribara Akiko , Morimoto Chiko , Ohnuma Kei , Paul Valerie J. , Ye Tao , Luesch Hendrik 
Published: March 2014

AbstractNatural products made by marine cyanobacteria are often highly modified peptides and depsipeptides that have the potential to act as inhibitors for proteases. In the interests of finding new protease inhibition activity and selectivity, grassypeptolide A (1) was screened against a panel of proteases and found to inhibit DPP8 selectively over DPP4. Grassypeptolides were also found to inhibit IL‐2 production and proliferation in activated T‐cells, consistent with a putative role of DPP8 in the immune system. These effects were also observed in Jurkat cells, and DPP activity in Jurkat cell cytosol was shown to be inhibited by grassypeptolides. In silico docking suggests two possible binding modes of grassypeptolides—at the active site of DPP8 and at one of the entrances to the internal cavity. Collectively these results suggest that grassypeptolides might be useful tool compounds in the study of DPP8 function.
SiliaCat Diphenylphosphine Palladium(II) Catalyzed Borylation of Aryl Halides
Authors: Pandarus Valerica , Marion Olivier , Gingras Geneviève , Béland François , Ciriminna Rosaria , Pagliaro Mario 
Published: March 2014

AbstractWe investigate the heterogeneously catalyzed direct synthesis of boronic acid pinacol esters using a wide range of aryl chlorides, bromides, and iodides, and bis(pinacolato)diboron as the borylating agent over the sol–gel entrapped SiliaCat diphenylphosphine palladium(II) catalyst. Optimization of the reaction conditions, scale‐up of the optimized process, and analysis of palladium leaching enabled us to establish a new selective route for direct access to a diverse set of boronic acid pinacol esters.
In Situ Study of Ethanol Electrooxidation on Monodispersed Pt3Sn Nanoparticles
Authors: Herranz Tirma , Ibáñez María , Gómez de la Fuente José L. , Pérez‐Alonso Francisco J. , Peña Miguel A. , Cabot Andreu , Rojas Sergio 
Published: March 2014

AbstractMonodispersed Pt3Sn nanoparticles were prepared through a mild thermal synthesis in the presence of surfactants. The performance of Pt3Sn for the electrooxidation of ethanol and adsorbed carbon monoxide (COad) in acid medium was studied by a combination of electrochemical and in situ spectroscopic methods, namely, infrared reflection absorption spectroscopy and differential electrochemical mass spectrometry (DEMS), and the results were compared to those obtained with the use of Pt black. The formation of the Pt3Sn solid solution promoted the oxidation of COad at less‐positive potentials than those required for Pt black. Also, the electrooxidation of ethanol, especially at lower potentials, was more favorable with Pt3Sn, as deduced from the higher faradaic currents recorded during the ethanol oxidation reaction (EOR). However, the distribution of products as deduced by DEMS analysis suggested that the formation of C1 products, CO2 inclusive, is less significant on Pt3Sn than on Pt. In fact, the higher faradaic current recorded with the former catalyst can be attributed to the greater amounts of acetaldehyde and acetic acid formed. After the EOR, the surface of both Pt and Pt3Sn remained covered by ethanol adsorbates. Whereas C2 fragments were the main adsorbates at the surface of Pt3Sn after the EOR, both C1 and C2 species remained adsorbed at Pt black.
Concurrent Phosphorus Doping and Reduction of Graphene Oxide
Authors: Poh Hwee Ling , Sofer Zdeněk , Nováček Michal , Pumera Martin 
Published: March 2014

AbstractDoped graphene materials are of huge importance because doping with electron‐donating or electron‐withdrawing groups can significantly change the electronic structure and impact the electronic and electrochemical properties of these materials. It is highly important to be able to produce these materials in large quantities for practical applications. The only method capable of large‐scale production is the oxidative treatment of graphite to graphene oxide, followed by its consequent reduction. We describe a scalable method for a one‐step doping of graphene with phosphorus, with a simultaneous reduction of graphene oxide. Such a method is able to introduce significant amount of dopant (3.65 at. %). Phosphorus‐doped graphene is characterized in detail and shows important electronic and electrochemical properties. The electrical conductivity of phosphorus‐doped graphene is much higher than that of undoped graphene, owing to a large concentration of free carriers. Such a graphene material is expected to find useful applications in electronic, energy storage, and sensing devices.
Cross‐Coupling Reaction of Saccharide‐Based Alkenyl Boronic Acids with Aryl Halides: The Synthesis of Bergenin
Authors: Parkan Kamil , Pohl Radek , Kotora Martin 
Published: March 2014

AbstractA convenient synthetic pathway enabling D‐glucal and D‐galactal pinacol boronates to be prepared in good isolated yields was achieved. Both pinacol boronates were tested in a series of cross‐coupling reactions under Suzuki–Miyaura cross‐coupling conditions to obtain the corresponding aryl, heteroaryl, and alkenyl derivatives in high isolated yields. This methodology was applied to the formal synthesis of the glucopyranoside moiety of papulacandin D and the first total synthesis of bergenin.
An Examination of the Scope and Stereochemistry of the Ireland–Claisen Rearrangement of Boron Ketene Acetals
Authors: Seizert Curtis A. , Ferreira Eric M. 
Published: March 2014

AbstractThe Ireland–Claisen rearrangement of boron ketene acetals is described. The boron ketene acetal intermediates are formed through a soft enolization that obviates the use of strong bases and the intermediacy of alkali metal enolates. Yields and diastereoselectivities of these rearrangements are very sensitive to the choice of boron reagent, even among those that have been shown to effect quantitative formation of boron ketene acetals from esters. The rearrangement occurs at room temperature for all substrates with generally high levels of stereoselectivity. In contrast to previous reports using boron triflates, the use of a commercially available boron iodide reagent allows for a wider substrate scope that extends to propionates and arylacetates, as well as the previously described α‐oxygenated esters. This work also provides insight into the dynamic nature of boron ketene acetals and the ramifications of this behavior for reactions in which they are intermediates.
Understanding Electrogenerated Chemiluminescence Efficiency in Blue‐Shifted Iridium(III)‐Complexes: An Experimental and Theoretical Study
Authors: Barbante Gregory J. , Doeven Egan H. , Kerr Emily , Connell Timothy U. , Donnelly Paul S. , White Jonathan M. , Lópes Thais , Laird Sarah , Wilson David J. D. , Barnard Peter J. , Hogan Conor F. , Francis Paul S. 
Published: March 2014

AbstractCompared to tris(2‐phenylpyridine)iridium(III) ([Ir(ppy)3]), iridium(III) complexes containing difluorophenylpyridine (df‐ppy) and/or an ancillary triazolylpyridine ligand [3‐phenyl‐1,2,4‐triazol‐5‐ylpyridinato (ptp) or 1‐benzyl‐1,2,3‐triazol‐4‐ylpyridine (ptb)] exhibit considerable hypsochromic shifts (ca. 25–60 nm), due to the significant stabilising effect of these ligands on the HOMO energy, whilst having relatively little effect on the LUMO. Despite their lower photoluminescence quantum yields compared with [Ir(ppy)3] and [Ir(df‐ppy)3], the iridium(III) complexes containing triazolylpyridine ligands gave greater electrogenerated chemiluminescence (ECL) intensities (using tri‐n‐propylamine (TPA) as a co‐reactant), which can in part be ascribed to the more energetically favourable reactions of the oxidised complex (M+) with both TPA and its neutral radical oxidation product. The calculated iridium(III) complex LUMO energies were shown to be a good predictor of the corresponding M+ LUMO energies, and both HOMO and LUMO levels are related to ECL efficiency. The theoretical and experimental data together show that the best strategy for the design of efficient new blue‐shifted electrochemiluminophores is to aim to stabilise the HOMO, while only moderately stabilising the LUMO, thereby increasing the energy gap but ensuring favourable thermodynamics and kinetics for the ECL reaction. Of the iridium(III) complexes examined, [Ir(df‐ppy)2(ptb)]+ was most attractive as a blue‐emitter for ECL detection, featuring a large hypsochromic shift (λmax=454 and 484 nm), superior co‐reactant ECL intensity than the archetypal homoleptic green and blue emitters: [Ir(ppy)3] and [Ir(df‐ppy)3] (by over 16‐fold and threefold, respectively), and greater solubility in polar solvents.
Metal‐Catalyzed Annulation Reactions for π‐Conjugated Polycycles
Authors: Jin Tienan , Zhao Jian , Asao Naoki , Yamamoto Yoshinori 
Published: March 2014

AbstractThe progress of the metal‐catalyzed annulation reactions toward construction of various π‐conjugated polycyclic cores with high conjugation extension is described. This article gives a brief overview of various annulation reactions promoted by metal catalysts including CH bond functionalization, [2+2+2] cycloaddition, cascade processes, ring closing metathesis, electrophilic aromatization, and various cross‐coupling reactions. A variety of conjugated polycycles with planar, bowl‐shaped, and helical structures have been constructed in high efficiency and selectivity.
Hydrodynamic and Water Quality Modeling of Lake Eğirdir
Authors: Kaçıkoç Meltem , Beyhan Mehmet 
Published: March 2014

AbstractThe main objective of this study was to determine the impact of current point and nonpoint pollution loads on the water quality of Lake Eğirdir. For this purpose, hydrodynamics and water quality status of Lake Eğirdir were investigated by using the Delft3D model. The monthly monitoring of pH, dissolved oxygen (DO), chlorophyll‐a (Chl‐a), and forms of nitrogen and phosphorus was carried out, as was the seasonal monitoring of total organic carbon. In all, seven different sampling points were chosen from the lake and influent streams in order to monitor the lake during the period from December 2010 to November 2011, with the aim of calibrating the model. The performance of the dynamic water quality model was evaluated using the relative root mean square error (RRMSE) values for both the calibration and the validation periods. The results of the model showed that the DO had the lowest, and Chl‐a had highest associated RRMSE value. The simulation results showed that Segments 1 and 7 of the system had relatively high concentrations of almost all the pollutants. It was also found that increasing the nonpoint nutrient loads from agricultural sources has a greater effect than increasing the nonpoint nutrient loads from the inhabited areas around the lake.
Using Stressor–Response Models to Derive Numeric Nutrient Criteria for Lakes in the Eastern Plain Ecoregion, China
Authors: Zhang Yali , Huo Shouliang , Ma Chunzi , Xi Beidou , Li Xiang , Liu Hongliang 
Published: March 2014

AbstractLakes in the Eastern Plain ecoregion of China are typically shallow, experience large disturbances, and are hydrologically connected to rivers. In recent years, lake eutrophication in this ecoregion has intensified due to human activities. To determine important regional nutrient criteria, the effects of hydrologic features and disturbances should be taken into account. In this paper, annual average data were used to construct stressor–response models for each hydrological lake type identified for lakes in the Eastern Plain ecoregion. In these models, total nitrogen (TN) and total phosphorus (TP) criteria were obtained from a chlorophyll a (Chl‐a, response variable) threshold value. A Chl‐a concentration of 4.73 μg L−1 was identified as this threshold value, which was based on the cyanotoxin limits associated with drinking water supply. The three lake types, which differed in hydrological structure, had significantly different TN and TP criteria. For example, lakes connected to the Yangtze River (T1) had a TN criterion ranging from 0.594 to 0.838 mg L−1, which was substantially higher than those for lakes that were never connected to the river (T3, 0.234–0.422 mg L−1). The exception to this trend occurred for lakes that were historically but not currently connected to the river (T2) due to P‐limitation in this lake type. However, there was little variability in the TP criterion among T1, T2, and T3 lakes, the values of which ranged from 0.021 to 0.037, 0.023 to 0.042, and 0.028 to 0.041 mg L−1, respectively.
Binding Kinetics of ZM241385 Derivatives at the Human Adenosine A2A Receptor
Authors: Guo Dong , Xia Lizi , van Veldhoven Jacobus P. D. , Hazeu Marc , Mocking Tamara , Brussee Johannes , IJzerman Adriaan P. , Heitman Laura H. 
Published: March 2014

AbstractClassical drug design and development rely mostly on affinity‐ or potency‐driven structure–activity relationships (SAR). Thus far, a given compound’s binding kinetics have been largely ignored, the importance of which is now being increasingly recognized. In the present study, we performed an extensive structure–kinetics relationship (SKR) study in addition to a traditional SAR analysis at the adenosine A2A receptor (A2AR). The ensemble of 24 A2AR compounds, all triazolotriazine derivatives resembling the prototypic antagonist ZM241385 (4‐(2‐((7‐amino‐2‐(furan‐2‐yl)‐[1,2,4]triazolo[1,5‐a][1,3,5]triazin‐5‐yl)amino)ethyl)phenol), displayed only minor differences in affinity, although they varied substantially in their dissociation rates from the receptor. We believe that such a combination of SKR and SAR analyses, as we have done with the A2AR, will have general importance for the superfamily of G protein‐coupled receptors, as it can serve as a new strategy to tailor the interaction between ligand and receptor.
Bis(dipyridophenazine)(2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid)ruthenium(II) Hexafluorophosphate: A Lesson in Stubbornness
Authors: Joshi Tanmaya , Pierroz Vanessa , Ferrari Stefano , Gasser Gilles 
Published: March 2014

AbstractRuthenium complexes are currently considered to be among the most promising alternatives to platinum anticancer drugs. In this work, thirteen structural analogues and organelle/receptor‐targeting peptide bioconjugates of a cytotoxic bis(dppz)‐RuII complex [Ru(dppz)2(CppH)](PF6)2 (1) were prepared, characterized, and assessed for their cytotoxicity and cellular localization (CppH=2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid; dppz=dipyrido[3,2‐a:2′,3′‐c]phenazine). It was observed that structural modifications (lipophilicity, charge, and size‐based) result in the cytotoxic potency of 1 being compromised. Confocal microscopy studies revealed that unlike 1, the screened complexes/bioconjugates do not have a preferential accumulation in mitochondria. The results of this important structure–activity relationship strongly support our initial hypothesis that accumulation in mitochondria is crucial for 1 to exert its cytotoxic action.
Bis(pentafluorosulfanyl)phenyl Azide as an Expeditious Tool for Click Chemistry toward Antitumor Pharmaceuticals
Authors: Yang Yu‐Dong , Tokunaga Etsuko , Akiyama Hidehiko , Saito Norimichi , Shibata Norio 
Published: March 2014

AbstractThe inclusion of fluorine in pharmaceutical agents is a well‐ established means of improving their druglike properties. Different substituents have been used to introduce fluorine, including trifluoromethyl and trifluoromethylthio groups; however, the pentafluorosulfanyl remains relatively underutilized although it is considered to be a “super” trifluoromethyl group. Here, a series of pentafluorosulfanyl‐containing 1,4‐disubstituted‐1,2,3‐triazoles were synthesized by click reaction from alkynes and 3,5‐bis(pentafluorosulfanyl)phenyl azide in excellent yields. Their biological activities were evaluated against human leukemic monocyte lymphoma U937 cells. In particular, 1‐(3,5‐bis(pentafluorosulfanyl)phenyl)‐4‐(4‐fluorophenyl)‐1H‐1,2,3‐triazole exhibited potent efficacy in cell viability assays at a concentration of 60 μM and was shown to activate caspase‐3 activity, indicating induction of apoptosis. An analogous fluorenol‐substituted triazole also exhibited promising cytotoxic effects against U937 cells, with an IC50 value of 6.29 μM. Given these preliminary results, these pentafluorosulfanyl‐containing triazoles represent useful building blocks for the further development of novel antitumor agents.