bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and synthesis of novel polycycles based on the 3H‐pyrrolo/6,7‐dihydropyrido[1,2‐a]indole scaffold as templates for pharmaceutical development
Authors: Derudas Marco , Pala Nicolino , Sanna Vanna , Dallocchio Roberto , Dessì Alessandro , Roggio Anna Maria , Sechi Mario 
Published: June 2011

AbstractIn the course of our work aimed at developing novel heterocycles of pharmaceutical interest, we designed and synthesized several polycyclic templates as potential substrates to be used in drug design. We obtained a set of condensed ring systems as versatile structural platforms to generate potential DNA‐interactive agents and/or reversible inhibitors of enzymes such as topoisomerases, poly(ADP‐ribose) polymerase‐1 (PARP‐1), telomerase, and, in particular, cyclin dependent kinases. Herein, we report the design, synthesis, structural investigation, and preliminary DNA‐binding affinity of these heteroaromatic systems. J. Heterocyclic Chem., (2011).
Neurotensin regulates cortical glutamate transmission by modulating N‐methyl‐D‐aspartate receptor functional activity: An in vivo microdialysis study
Authors: Ferraro Luca , Beggiato Sarah , Tomasini Maria Cristina , Fuxe Kjell , Tanganelli Sergio , Antonelli Tiziana 
Published: June 2011

AbstractThe aim of the present in vivo microdialysis study was to investigate whether the tridecapeptide neurotensin (NT) influences the N‐methyl‐D‐aspartate (NMDA) receptor‐mediated increase of cortical glutamate transmission in freely moving rats. Intracortical perfusion with NT influenced local extracellular glutamate levels in a bell‐shaped, concentration‐dependent manner. One hundred and three hundred nanomolar NT concentrations increased glutamate levels (151% ± 7% and 124% ± 3% of basal values, respectively). Higher (1,000 nM) and lower (10 nM) NT concentrations did not alter extracellular glutamate levels. The NT receptor antagonist SR48692 (100 nM) prevented the NT (100 nM)‐induced increase in glutamate levels. NMDA (100 and 500 μM) perfusion induced a concentration‐dependent increase in extracellular glutamate levels, the lower 10 μM NMDA concentration being ineffective. When NT (10 nM, a concentration by itself ineffective) was added in combination with NMDA (100 μM) to the perfusion medium, a significant greater increase in extracellular glutamate levels (169% ± 7%) was observed with respect to the increase induced by NMDA (100 μM) alone (139% ± 4%). SR48692 (100 nM) counteracted the increase in glutamate levels induced by the treatment with NT (10 nM) plus NMDA (100 μM). The enhancement of cortical glutamate levels induced by NMDA (100 and 500 μM) was partially antagonized by the presence of SR48692, at a concentration (100 nM) that by itself was ineffective in modulating glutamate release. These findings indicate that NT plays a relevant role in the regulation of cortical glutamatergic transmission, especially by modulating the functional activity of cortical NMDA receptors. A possible role in glutamate‐mediated neurotoxicity is suggested. © 2011 Wiley‐Liss, Inc.
Quantifying intra‐osseous growth of osteosarcoma in a murine model with radiographic analysis
Authors: Cole Heather A. , Ichikawa Jiro , Colvin Daniel C. , O'Rear Lynda , Schoenecker Jonathan G. 
Published: June 2011

AbstractThe orthotopic murine osteosarcoma model is an excellent representation of the human condition as mice develop rapid growth of ‘primary’ tumor with subsequent lung metastasis. Currently, monitoring tumor growth relies on measuring pulmonary metastases occurring four weeks post injection. Studies show that amputation of the tumor‐bearing limb is required before pulmonary metastases are detectable due to rapid growth causing morbidity. Thus, a method measuring ‘primary’ tumor growth independent of metastasis is required. We hypothesized that serial radiography would allow for longitudinal quantification of ‘primary’ osteosarcoma growth and explored this idea by utilizing the tibial orthotopic model. Tumor growth was monitored weekly by radiography and calipers, and results were compared with µCT and histology. We found that radiographs demonstrate extra and intra‐osseous tumor growth by displaying lytic and blastic lesions and the surrounding radio‐opaque area enlarged significantly (p < 0.0001) allowing for quantification. Additionally, radiographs proved more precise than indirect caliper measurements (intra‐observer error ±6.64%: inter‐observer error ±15.84%). Therefore, we determined that radiography provides accurate, longitudinal quantification of ‘primary’ osteosarcoma tumor that can be performed serially in the same mouse, does not require introduction of bioluminescence to the host or cell, and is more precise than the current caliper method. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1957–1962, 2011
Determination of 2‐ethylhexyl nitrate in diesel fuel
Authors: Dvořák Bohuslav , Bajerová Petra , Eisner Aleš , Nykodýmová Olga , Ventura Karel 
Published: June 2011

AbstractThe aim of this study was to develop and validate fast and easily applicable GC/MS assay for the quantification of the substance that increases cetane number in diesel fuel (2‐ethylhexylnitrate, 2‐EHN). These requirements were fulfilled best by a headspace GC‐MS assay with negative chemical ionization with methane (HS‐GC/MS). Chromatographic separation is achieved using a DB5‐MS capillary column after the addition of known amount of internal standard (o‐nitrotoluene). The limit of detection was 0.009% v/v for 2‐EHN and the limit of quantification was 0.03% v/v. The HS‐GC/MS method was applied for the quantification of cetane improver in spiked diesel fuel and real diesel fuel. The method is linear over the studied range (0.03–0.3%, v/v), with satisfactory intra‐ and inter‐assay precision, and the relative standard deviations are lower than 10%. Good accuracy is achieved with bias <10% at all levels tested.
Zinc deprivation inhibits extracellular matrix calcification through decreased synthesis of matrix proteins in osteoblasts
Authors: Alcantara Ethel H. , Lomeda Ria‐Ann R. , Feldmann Joerg , Nixon Graeme F. , Beattie John H. , Kwun In‐Sook 
Published: June 2011

AbstractScope: Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts.Methods and Results: Two osteoblastic MC3T3‐E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn–, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn– decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency‐induced detrimental effects on extracellular matrix mineralization. Zn– also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn–, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn–.Conclusion: Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification.
Affinity of vitamin E analogues for the ubiquinone complex II site correlates with their toxicity to cancer cells
Authors: Neuzil Jiri , Cerny Jiri , Dyason Jeffrey C. , Dong Lan‐Feng , Ralph Stephen J. 
Published: June 2011

AbstractScope: Vitamin E (VE) analogues, epitomised by the prototypic α‐tocopheryl succinate (α‐TOS), are potent anti‐cancer agents. α‐TOS has recently been shown to trigger apoptosis by targeting the ubiquinone (UbQ) binding site(s) of the mitochondrial complex II (CII) and to cause excessive production of reactive oxygen species.Methods and results: We have modelled, using two approaches, a range of VE analogues into the proximal UbQ (Qp) binding site of CII. This study reveals that in both cases, the calculated interaction energies of individual VE analogues correlate (R2 value >0.8) with their toxicity to cancer cells.Conclusion: These data further support the UbQ site(s) of CII as an important target determining the anti‐cancer activity of VE analogues as well as other emerging anti‐cancer drugs.
Dicaffeoylquinic acids in Yerba mate (Ilex paraguariensis St. Hilaire) inhibit NF‐κB nucleus translocation in macrophages and induce apoptosis by activating caspases‐8 and ‐3 in human colon cancer cells
Authors: Puangpraphant Sirima , Berhow Mark A. , Vermillion Karl , Potts Greg , Gonzalez de Mejia Elvira 
Published: June 2011

AbstractScope: The biological functions of caffeoylquinic acid (CQA) derivatives from various plant sources have been partially elucidated. The objectives were to isolate and purify diCQAs from Yerba mate tea leaves and assess their anti‐inflammatory and anti‐cancer capabilities in vitro and explore their mechanism of action.Methods and results: Methanol extracts of dried mate leaves were resolved by flash chromatography and further purified resulting in two fractions one containing 3,4‐ and 3,5‐diCQAs and the other 4,5‐diCQA with NMR‐confirmed structures. Both fractions inhibited LPS‐induced RAW 264.7 macrophage inflammation by suppressing nitric oxide/inducible nitric oxide and prostaglandin E2/cyclooxygenase‐2 pathways through inhibiting nucleus translocation of Nuclear factor κB subunits, p50 and p65. The diCQA fractions inhibited Human colon cancer cells CRL‐2577 (RKO) and HT‐29 cell proliferation by inducing apoptosis in a time‐ and concentration‐dependent manner, but did not affect the protein levels of p21, p27, p53, and Bax:Bcl‐2 ratio in RKO cells. In HT‐29 cells, however, the diCQA fractions increased Bax:Bcl‐2 ratio. The diCQA fractions increased the activation of caspase‐8 leading to cleavage of caspase‐3 in both RKO and HT‐29 colon cancer cells.Conclusion: The results suggest that diCQAs in Yerba mate could be potential anti‐cancer agents and could mitigate other diseases also associated with inflammation.
The influence of Cd(ZnO) on the structure, optical and thermal stabilities of polyvinyl chloride nanocomposites
Authors: Mahmoud Waleed E. , Al‐Ghamdi A. A. 
Published: June 2011

AbstractThe doping of nanomaterials into polymers creates novel nanocomposite materials with desired properties. The influence of these nanoscale fillers on the structure and optical and thermal stabilities of polymer are the crucial clue to introduce these novel nanocomposites to service life applications. In this work, cadmium doped zinc oxide (Cd0.5Zn0.5O) nanopowders with a uniform particle size of around 10 nm have been synthesized, purified, and blended with polyvinyl chloride (PVC) by solution mixing to prepare PVC/Cd0.5Zn0.5O nanocomposite films. The structure and morphology of PVC/Cd0.5Zn0.5O nanocomposite films have been characterized using transmission electron microscopy. The results showed that as the amount of nanoscale fillers increases the nanocrystals tend to aggregates and the size of these aggregates increases from 25 to 100 nm. The UV–vis spectra showed that the prepared PVC/Cd0.5Zn0.5O nanocomposite films are highly transparent. The transparency at higher concentrations slightly decreased as a consequence of light scattering due to large aggregates. The thermogravimetric results showed that a small amount of Cd0.5Zn0.5O nanopowders (<0.6 wt%) without further surface modification can greatly improve the thermal stability of PVC. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Rapid Identification of Calotropagenin Glycosides Using High‐Performance Liquid Chromatography Electrospray Ionisation Tandem Mass Spectrometry
Authors: Kanojiya Sanjeev , Madhusudanan K. P. 
Published: June 2011

IntroductionCardiac glycosides in Calotropis procera have therapeutic use as inhibitors of Na+/K+‐ATPase to regulate heart contractions. A large amount of research attention has been received by these compounds towards their identification and structural characterisation. In order to achieve rapid identification of cardiac glycosides in phytochemical extracts a liquid chromatography tandem mass spectrometry (LC‐MS/MS) method has been developed involving metal cationisation by post‐column addition of alkali salts for the unambiguous determination of their molecular weights.ObjectiveIdentification of cardiac glycosides in Calotropis procera leaf extract.ResultsCalotropagenin and its 10 glycosides were unambiguously identified. The daughter ions at m/z 387, 369, 359, 351, 341 and 323 in their MS/MS spectra were attributed to the calotropagenin aglycone unit.ConclusionHigh performance liquid chromatography in combination with electrospray ionization tandem mass spectrometry involving metal cationisation by post column addition of alkali salts was successfully utilised for the rapid identification of calotropagenin glycosides/derivatives in Calotropis procera extract. Copyright © 2011 John Wiley & Sons, Ltd.
Amniopatch for iatrogenic rupture of the fetal membranes
Authors: Deprest Jan , Emonds Marie‐Paule , Richter Jute , DeKoninck Philip , Van Mieghem Tim , Van Schoubroeck Dominique , Devlieger Roland , De Catte Luc , Lewi Liesbeth 
Published: June 2011

AbstractWith the increased use of invasive fetal procedures, the number of women facing post‐procedure membrane rupture is increasing. Here we review the use of platelets and fresh frozen plasma for sealing iatrogenic fetal membrane defects by describing the mechanisms of action of the amniopatch procedure as well as published experience. In cases of iatrogenic preterm pre‐labour rupture of the membranes, amniopatch effectively seals the fetal membranes in over two‐thirds of cases. There is a risk of 16% of in utero fetal death, which may occur at varying intervals from the procedure and often for unknown reasons. Amniopatch has also been used as a treatment of chorionic membrane separation. In summary, current experience suggests that in cases of early onset but persistent amniotic fluid leakage following an invasive fetal procedure, amniopatch is an option. Copyright © 2011 John Wiley & Sons, Ltd.
NMR investigation of aniline oligomers produced in the oxidation of aniline in alkaline medium
Authors: Kříž Jaroslav , Konyushenko Elena N , Trchová Miroslava , Stejskal Jaroslav 
Published: June 2011

AbstractThe chloroform‐soluble products of aniline or (15N)aniline oxidation in alkaline medium were analysed using one‐ and two‐dimensional 1H NMR, 13C NMR and 15N NMR spectroscopy. Among the products, two were found to be prominent, namely a carbonyl‐containing semiquinonoid and a phenazine‐like structure. The probable mechanism of their formation is suggested. Copyright © 2011 Society of Chemical Industry
Oriented structure in stretched isotactic polypropylene melt and its unexpected recrystallization: optical and X‐ray studies
Authors: Zheng Guoqiang , Jia Zhenhua , Li Songwei , Dai Kun , Liu Baochen , Zhang Xiaoli , Mi Liwei , Liu Chuntai , Chen Jingbo , Shen Changyu , Peng Xiangfang , Li Qian 
Published: June 2011

AbstractAt an extremely small extrusion rate, an isotactic polypropylene melt was extruded through a slit die of an extruder. Simultaneously, the extruded melt was stretched at various stretching rates (SRs) at the die exit. The oriented structure and its subsequent recrystallization via self‐seeding were investigated using polarized optical microscopy, two‐dimensional wide‐angle X‐ray scattering and small‐angle X‐ray scattering. As expected, much slenderer and denser oriented structures were formed at larger SR, which indicates that orientation is preferably promoted with increasing SR. In the case of the crystalline morphology developed during recrystallization, a shish kebab‐like structure was retrieved via the surviving oriented structure after annealing. Unexpectedly, for the sheet stretched at higher SR, a mainly sparse and short shish kebab structure was observed. For the sheet stretched at lower SR, a dense and long shish kebab structure was observed. This suggests that the oriented structure in the sheet stretched at lower SR has a better thermal stability than that in the sheet stretched at higher SR. This is discussed based on the relaxation of entangled junctions in the stretched networks with respect to varying chain length. Copyright © 2011 Society of Chemical Industry
Low‐bandgap donor–acceptor copolymers with 4,6‐bis(3′‐(2‐ethylhexyl)thien‐2′‐yl)thieno[3,4‐c][1,2,5]thiadiazole: synthesis, optical, electrochemical, and photovoltaic properties
Authors: Cimrová Věra , Kmínek Ivan , Pavlačková Petra , Výprachtický Drahomír 
Published: June 2011

AbstractTwo new low‐bandgap alternating copolymers (CEHTF and CEHTP) consisting of 4,6‐bis(3′‐(2‐ethylhexyl)thien‐2′‐yl)thieno[3,4‐c][1,2,5] thiadiazole and 9,9‐bis(2‐ethylhexyl)fluorene or 2,5‐bis(isopentyloxy)benzene were synthesized by Suzuki coupling reaction of corresponding comonomers. Their optical, electrochemical, and photovoltaic (PV) properties were studied and are reported. Both the copolymers exhibited long‐wavelength absorption covering the whole visible spectral region, which is in CEHTP thin films extended up to near infrared region, ambipolar redox properties, and electrochromism. High‐electron affinities and low‐optical bandgap values, 1.37 and 1.15 eV, were determined for CEHTF and CEHTP, respectively. PV devices with bulk heterojunction made of blends of copolymers and fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester ([60]PCBM) were prepared and characterized. Effects of intramolecular charge transfer strength and side‐chain nature and length on photophysical properties are discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Pyrenylamine‐functionalized aromatic polyamides as efficient blue‐emitters and multicolored electrochromic materials
Authors: Kung Yi‐Chun , Hsiao Sheng‐Huei 
Published: June 2011

AbstractA series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and fluorescent properties of model compounds for conjugated polymer containing maleimide units at the main chain
Authors: Onimura Kenjiro , Matsushima Mieko , Nakamura Munetoshi , Tominaga Tatsuya , Yamabuki Kazuhiro , Oishi Tsutomu 
Published: June 2011

Abstract2,3‐Diaryl substituted maleimides as model compounds of conjugated maleimide polymers [poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar)] were synthesized from 2,3‐dibromo‐N‐substituted maleimide (DBrRMI) [R= cyclohexyl (DBrCHMI) and n‐hexyl (DBrHMI)] and aryl boronic acid using palladium catalysts. To clarify structures of conjugated polymer containing maleimide units at the main chain, 13C NMR spectra of 2‐aryl or 2,3‐diaryl substituted maleimides were compared with those of N‐substituted maleimide polymers. Copolymers obtained with DBrRMI via Suzuki‐Miyaura cross‐coupling polymerizations or Yamamoto coupling polymerizations were dehalogenated structures at the terminal end. This dehalogenation may contribute to the low polymerizability of DBrRMIs. On the other hand, the π‐conjugated compounds showed high solubility in common organic solvents. The N‐substituents of maleimide cannot significantly affect the photoluminescence spectra of 2,3‐diaryl substituted maleimides derivatives. The fluorescence spectra of poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar) varied with N‐substituents of the maleimide ring. When exposed to ultraviolet light of wavelength 352 nm, a series of 1,4‐phenylene‐ and/or 2,5‐thienylene‐based copolymers containing N‐substituted maleimide derivatives fluoresced in a yellow to blue color. It was found that photoluminescence emissions and electronic state of π‐conjugated maleimide derivatives were controlled by aryl‐ and N‐substituents, and maleimide sequences of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
ATRP of MMA under 60Co γ‐irradiation at room temperature
Authors: Chen Qifeng , Zhang Zhengbiao , Zhou Nianchen , Cheng Zhenping , Zhu Jian , Zhang Wei , Zhu Xiulin 
Published: June 2011

AbstractIn this work, atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was successfully carried out at room temperature (25 °C) under 60Co γ‐irradiation environment. The polymerization proceeded smoothly with high conversion (>90%) within 7 h. The polymerizations kept the features of controlled radical polymerization: first‐order kinetics, well‐predetermined number‐average molecular weights (Mn,GPC), and narrow molecular weight distributions (Mw/Mn < 1.25). 1H NMR spectroscope and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry confirmed that poly(methyl methacrylate) (PMMA) chain was end‐capped by the initiator moieties. The Cu(II) concentration could reduce to 20 ppm level while keeping good control over molecular weights. This is the first successful example for the ATRP of MMA under 60Co γ‐irradiation at room temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011