bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of independent mechanism upon poly(ADP‐ribose) polymerase (PARP) activation in methylmercury cytotoxicity in rat cerebellar granule cell culture
Authors: Sakaue Motoharu , Mori Naoko , Okazaki Maiko , Ishii Mayuka , Inagaki Yayoi , Iino Yuka , Miyahara Kiyomi , Yamamoto Mai , Kumagai Takeshi , Hara Shuntaro , Yamamoto Masako , Arishima Kazuyoshi 
Published: July 2008

AbstractPoly(ADP‐ribose) polymerase (PARP) activation plays a role in repairing injured DNA, while its overactivation is involved in various diseases, including neuronal degradation. In the present study, we investigated the use of a PARP inhibitor, 3,4‐dihydro‐5‐[4‐(1‐piperidinyl)butoxy]‐1(2H)‐isoquinolinone (DPQ), whether methylmercury‐induced cell death in the primary culture of cerebellar granule cells involved PARP activation. DPQ decreased the methylmercury‐induced cell death in a dose‐dependent manner. Unexpectedly, this protective effect was DPQ specific; none of the other PARP inhibitors—1,5‐dihydroxyisoquinoline, 3‐aminobenzamide, or PJ34—affected neuronal cell death. Methylmercury‐induced cell death involves the decrease of glutathione (GSH) and production of reactive oxygen species. Therefore, to understand the mechanism by which DPQ inhibits cytotoxicity, we first studied the effect of DPQ on buthionine sulfoximine– or diethyl maleate–induced death of primary cultured cells and human neuroblastoma IMR‐32 cells, both of which are mediated by GSH depletion. DPQ inhibited the cell death of both cultured cells, but it did not restore the decrease of cellular GSH by buthionine sulfoximine to the control level. Second, we evaluated the antioxidant activity of PARP inhibitors by methods with ABTS (2‐2′‐azinobis(3‐ethylbenzothiazoline 6‐sulfonate) or DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) used as a radical because antioxidants also efficiently suppress methylmercury‐induced cell death. The antioxidant activity of DPQ was the lowest among the tested PARP inhibitors. Taken together, our results indicate that DPQ effectively protects cells against methylmercury‐ and GSH depletion–induced death. Furthermore, they suggest that DPQ exerts its protective effect through a mechanism other than PARP inhibition and direct antioxidation, and that PARP activation is not involved in methylmercury‐induced neuronal cell death. © 2008 Wiley‐Liss, Inc.
Adenosine produced by neurons is metabolized to hypoxanthine by astrocytes
Authors: Zamzow Christina R. , Xiong Wei , Parkinson Fiona E. 
Published: July 2008

AbstractAdenosine (ADO) is an important neuromodulator in brain. During pathophysiological events such as stroke or brain trauma, ADO levels can increase up to 100‐fold. We tested the hypothesis that astrocytes are important for the removal of ADO produced by neurons and for the metabolism of ADO to inosine (INO) and hypoxanthine (HX). We used four different cell culture preparations: cortical neurons, cortical astrocytes, cocultures of neurons and astrocytes, and neurons transiently cocultured with astrocytes on transwell filters. These cultures were treated with N‐methyl‐D‐aspartate (NMDA), because NMDA receptor activation is a common factor among many causes of neurotoxicity. NMDA significantly increased extracellular ADO, INO, and HX levels from cultured cortical neurons by 3‐, 3.5‐, and 2‐fold, respectively. In cocultures, NMDA significantly increased INO, by 4.5‐fold, and HX, by 3‐fold, but did not increase ADO levels. There was no NMDA‐evoked purine production from astrocytes. Inhibition of purine nucleoside phosphorylase (PNP) significantly decreased HX production from both neurons and cocultures to less than 30% of control levels. The transient addition of astrocytes to neurons during NMDA treatment significantly increased HX and decreased ADO levels compared with neurons alone. In addition, increasing the number of astrocytes was directly correlated with an increased capacity of ADO metabolism to INO and HX. In conclusion, NMDA evoked the production of ADO, INO, and HX from neurons. In the presence of astrocytes, there was significantly less ADO and more HX produced. Thus, ADO produced by neurons is subject to metabolism by astrocytes, a process that may limit its neuromodulatory actions. © 2008 Wiley‐Liss, Inc.
Palaeoenvironment and biogeography of a late MIS 3 fossil beetle fauna from South Taranaki, New Zealand
Authors: Marra M. J. , Crozier M. , Goff J. 
Published: July 2008

AbstractFossil beetles from a last glacial landslide‐generated lake‐forest sequence aged 33 480–34 410 cal. yr BP (late Marine Isotope Stage 3 (MIS 3)) are identified from the Waitotara Valley in South Taranaki, North Island, New Zealand. The stratigraphy indicates that the landslide caused changes to local hydrology, resulting in the formation of a lake‐swamp environment and subsequent transition to forest. Fossil leaves suggest a forest dominated by Nothofagus menziesii, and radiocarbon ages indicate the site was forested for around 4000 yr. A fossil beetle‐based temperature estimate using the maximum likelihood envelope method indicates the climate was cooler than present day. The distributions of the fossil beetle taxa are examined and compared with the modern ecological patterns. The fossil fauna is very typical of a modern‐day Nelson (northern South Island) fauna. None of the beetle species is present in the modern South Taranaki fauna and many taxa such as Platypus caviceps, Alema paradoxa, Rhyzobius consors, Syrphetodes ater, Cyclaxyra impressa and species of Grynoma and Pycnomerus are now absent from part or all of the lower North Island. This is important because the lower North Island is currently an area of low diversity and endemism and these results suggest this biogeographical pattern stems from the last glaciation. Copyright © 2008 John Wiley & Sons, Ltd.
Sub‐millennial climate shifts in the western Mediterranean during the last glacial period recorded in a speleothem from Mallorca, Spain
Authors: Hodge Edward J. , Richards David A. , Smart Peter L. , Ginés Angel , Mattey David P. 
Published: July 2008

AbstractVery few high‐resolution and directly dated terrestrial archives of the last glacial period exist for the western Mediterranean region, yet this is a key locality for recording sub‐millennial North Atlantic and Mediterranean climate change. Here, we present evidence of effective precipitation changes based on growth history and δ13C of calcite in a Mallorcan stalagmite that grew between 112 and 48 ka. Effective precipitation in Mallorca appears to have been sensitive to proximal sea surface temperature variations and at certain times, ca. 76 ka for example, changed rapidly from moist to arid conditions in only a few centuries. A sea‐level highstand during Marine Isotope Stage (MIS) 5a interrupted growth. Regrowth started promptly after this, but effective precipitation decreased markedly for much of the later part of MIS 5a, and also for shorter periods correlative with Heinrich events H8 (ca. 90 ka) and H6 (ca. 65 ka), with growth ceasing during H5 (ca. 48 ka). Arid episodes in Mallorca appear to be expressions of extremely cold periods recorded further north in Europe and occur contemporaneously with rapid decreases in Greenland temperature. Copyright © 2008 John Wiley & Sons, Ltd.
Changes in flour gelatinisation of trifoliate yam (Dioscorea dumetorum) tubers after harvest
Authors: Medoua Gabriel Nama , Mbofung Carl MF 
Published: July 2008

AbstractBACKGROUND: Changes in the properties of starch during postharvest hardening of trifoliate yam (Dioscorea dumetorum) tubers need to be investigated. In this work the starch gelatinisation kinetics of D. dumetorum cv. Yellow stored under prevailing tropical ambient conditions (0.98–2.32 kg vapour per 100 m3 airflow) for 0, 2, 7, 14, 21 and 28 days was studied using a 3 × 5 factorial experiment with three cooking temperature (75, 85 and 95 °C) and five cooking times (0, 5, 10, 20 and 40 min). Samples were also evaluated for starch properties and gelatinisation temperature.RESULTS: Storage of D. dumetorum tubers caused starch damage. However, the starch gelatinisation temperature was between 70 and 75 °C irrespective of the tuber storage duration. The starch gelatinisation reaction followed first‐order kinetics defined by the relationship ln(1 − α) = − kGt. The gelatinisation rate was significantly influenced (P≤0.05) by cooking temperature and increased with tuber storage duration. The activation energy also increased with tuber storage duration.CONCLUSION: Although the gelatinisation temperature of D. dumetorum starch was not influenced by tuber storage, the starch gelatinisation process was affected by tuber storage duration, since tuber storage involved a greater need of energy for starch gelatinisation, which may be an effect of the postharvest hardening phenomenon. Copyright © 2008 Society of Chemical Industry
Effect of pyruvic acid and ascorbic acid on stability of 3‐deoxyanthocyanidins
Authors: Ojwang Leonnard , Awika Joseph M 
Published: July 2008

AbstractBACKGROUND: 3‐Deoxyanthocyanins are a rare class of plant pigments primarily found in sorghum and known to possess distinct chemical and bioactive properties. They have potential as natural food colourants. This work investigates how 3‐deoxyanthocyanin pigments react with pyruvic acid and their stability in the presence of ascorbic acid.RESULTS: Substitution at C‐5 was the major determinant of the mechanism of 3‐deoxyanthocyanidin complexation with pyruvic acid: hydroxyl substitution favoured cyclic condensation, whereas methoxyl substitution favoured oxidative ring contraction. Pure 3‐deoxyanthocyanidins generally showed poor stability in the presence of 500 mg L−1 ascorbic acid at pH 2.0 and 3.2 but were stable at pH 5.0; pyruvic acid improved their stability at pH 2.0 and 3.2 and enhanced their colour intensity at pH 5.0. Crude sorghum pigment extract was very stable in the presence of ascorbic acid: 31% colour loss at pH 2.0; 1.9‐ and 1.3‐fold increases in colour intensity at pH 3.2 and 5.0 respectively. In contrast, red cabbage pigment lost 30–85% of its colour in the presence of ascorbic acid under the conditions used in the study.CONCLUSION: Crude sorghum pigments are very stable in the presence of ascorbic acid and may be useful as natural food colourants. Copyright © 2008 Society of Chemical Industry
Influences of weather, cultivar and fertiliser rate on grain protein polymer accumulation in field‐grown winter wheat, and relations to grain water content and falling number
Authors: Johansson Eva , Prieto‐Linde Maria Luisa , Gissén Charlott 
Published: July 2008

AbstractBACKGROUND: The reasons for variations in the amount and size distribution of polymeric protein in mature wheat, related to bread‐making quality, are not fully understood and can be sought during the protein polymer formation period of grain maturation. The present study was aimed at investigating the accumulation and polymerisation of grain storage proteins during grain maturation and their relations to changes in falling number and grain water content in four cultivars of field‐grown winter wheat.RESULTS: Proteins were accumulated and polymerised similarly during grain development independently of cultivation environment, cultivar and fertiliser rate. A 3–6 day delay in maturity among cultivars led to a 3–12 day delay in protein accumulation during early grain development. An increase in nitrogen fertiliser rate from 160 to 200 kg N ha−1 resulted in a 20% increase in the amount of sodium dodecyl sulfate (SDS)‐unextractable protein. Precipitation just before grain harvesting led to 40–50% increases in grain water content and 8–34% decreases in the amount of SDS‐unextractable monomeric protein. At increased grain water contents the fertiliser rate was negatively related to the amount of grain SDS‐unextractable protein.CONCLUSION: Accumulation and polymerisation of grain storage proteins are predetermined events in wheat. Grain moisture content is negatively related to grain storage protein polymerisation, although the rate of decrease is influenced by the fertiliser regime. Copyright © 2008 Society of Chemical Industry
Juvenile nasopharyngeal angiofibroma: Clinical factors associated with recurrence, and proposal of a staging system
Authors: Carrillo J.F. , Maldonado F. , Albores O. , Ramírez‐Ortega M.C. , Oñate‐Ocaña L.F. 
Published: July 2008

AbstractBackgroundJuvenile nasopharyngeal angiofibroma (JNA) is a vascular tumor of the nasopharynx. Our aim is to analyze prognostic factors, report results obtained with radiation therapy and propose a staging system.Materials and MethodsRetrospective study of patients with JNA. Clinical, radiological and therapeutic data were assessed for recurrence‐ and disease free survival‐associated prognostic factors. Bivariate and multivariate analyses were performed.ResultsFifty‐four males were analyzed. Invasion to anterior infratemporal fossae (ITF) +/or to pterygomaxillary fossae, to posterior infratemporal fossae, or intracranial extension were associated with recurrences in 2 of 15, in 8 of 18, and in 8 of 12 cases, respectively. Tumors < or ≥6 cm were associated with zero and with 18 recurrences, respectively (P = 0.006). A staging system is constructed considering extension patterns and size. Multivariate analyses conferred significance (P = 0.002) to a model including this staging system and surgical margins.ConclusionOur system stratifies recurrence risk and disease‐free survival efficiently. Since radiotherapy at young age has potential to induce malignancies, it should be used with caution. It could be considered as primary treatment in stage IV cases with major invasion to cavernous sinus or orbital apex. Therapy design may be improved. J. Surg. Oncol. 2008;98:75–80. © 2008 Wiley‐Liss, Inc.
A modified grading system for post‐hepatectomy metastatic liver cancer originating from colorectal carcinoma
Authors: Nanashima Atsushi , Sumida Yorihisa , Abo Takafumi , Tobinaga Syuuichi , Takeshita Hiroaki , Hidaka Shigekazu , Yasutake Toru , Nagayasu Takeshi , Mine Mariko , Sawai Terumitsu 
Published: July 2008

AbstractBackground and ObjectivesThere is no appropriate grading system for prediction of survival of patients with metastatic liver cancer (MLC) from colorectal carcinoma. We propose the modified grading system for MLC from the present Japanese system.MethodsWe compared predictive accuracies of survival of 121 Japanese MLC patients of five systems, including clinical risk score (CRS) proposed by Memorial‐Sloan‐Kettering‐Cancer‐Center, original H‐number (OHN) by Japanese Society for Cancer of the Colon and Rectum, revised H‐number (RHN) and Grade by the same society (GJSCCR), and our modified Grade (MGJSCCR) based on OHN and presence of primary lymph node metastasis.ResultsUnivariate analysis showed that discrimination of both disease‐free and overall survival rates was significant for CRS, OHN and MGJSCCR (P < 0.05) but not for RHN and GJSCCR. Multivariate analysis showed CRS and MGJSCCR as the best systems for predicting disease‐free and overall survival according to disease stage, for which Akaike information criteria (AIC) value was the lowest (423.7 and 313.9, hazard ratio 1.73 and 1.47, respectively for CRS, 423.9 and 313.5, hazard ratio 1.75 and 1.69, respectively for MGJSCCR; P < 0.05).ConclusionsThe simpler system of MGJSCCR is a better predictive grading system of prognosis of MLC patients who had undergone hepatic resection. J. Surg. Oncol. 2008;98:363–370. © 2008 Wiley‐Liss, Inc.
Social impacts of tourism: an Australian regional case study
Authors: Tovar Cesar , Lockwood Michael 
Published: July 2008

AbstractAs the support of host communities is a precondition for a sustainable industry, regional social impact studies are a crucial input to tourism planning and decision‐making. This study assessed the social impacts of tourism in a rural region of Australia where tourism is an important sector of the economy. As well as providing data to aid regional tourism planning, this study identifies differences in personal and community‐wide impacts; advances understanding of the factors that influence residents' perceptions of tourism impacts; and assesses the degree to which tourism activity associated with protected areas contributes to the identified social impacts. Copyright © 2008 John Wiley & Sons, Ltd.
The process of 4‐hydroxybiphenyl synthesis from 4‐isopropylbiphenyl
Authors: Stec Zbigniew , Orlińska Beata , Jakubowski Bartłomiej , Zawadiak Jan 
Published: July 2008

AbstractThe kinetics of the oxidation of 4‐isopropylbiphenyl (1) in the liquid phase by oxygen to 1‐(1,1′‐biphenyl‐4‐yl)‐1‐methylethyl hydroperoxide (2) was investigated. The oxidizability of 1 in the temperature range from 60°C to 120°C and the overall energy activation of oxidation were determined. Long‐term oxidation of 1 to 2 in the temperature range of 80–120°C was investigated, and the yield and selectivity of the process were determined. Pure 2 was obtained, and its properties were defined. 4‐Hydroxybiphenyl was obtained as a result of the acidic decomposition of 2. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 527–532, 2008
Kinetics and mechanism for oxime formation from benzoylformic acid: Electrostatic interactions in the dehydration of carbinolamines
Authors: Malpica A. , Calzadilla M. , Mejias I. 
Published: July 2008

AbstractThe evidence establishes that oxime formation from benzoylformic acid in the pH range from 0.25 to 5.5 occurs with acid‐catalyzed dehydration of carbinolamines derived from the acid and its anion. The pH‐rate profile shows in order of decreasing pH in two regions: (1) In the pH range from 5.5 to ∼2.2 the second‐order rate constants are linearly dependent on the concentration of hydronium ion and (2) from pH ∼2.2 to 0.25 the rate constants deviate slightly from the line of slope = −1. This slight deviation is a consequence of the very similar values of limiting rate constants of the two forms of the substrate. Electrostatic interactions between charged carbinolamines and hydronium ions are analyzed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 554–558, 2008
Inorganic‐Organic Hybrid Polymers Based on Surface‐Modified Metal Oxide Clusters
Authors: Schubert Ulrich 
Published: July 2008

AbstractTransition metal oxide clusters with unsaturated carboxylate ligands bonded to their surface were polymerized in the presence of organic co‐monomers by various polymerization techniques to form cluster‐reinforced polymers. The properties of the cluster‐crosslinked hybrid polymers are distinctly different to those of the parent polymers and originate from both crosslinking and filler effects. Variation of the cluster proportion, the kind of employed cluster, the ratio of functional and non‐functional capping ligands and the polymerization conditions allows modifying the materials properties of the hybrid materials. The most important changes in materials properties compared with the cluster‐free polymers relate to the swelling behavior, thermal stability and mechanical properties. Furthermore, cluster‐specific properties can be introduced into the polymers, such as magnetic properties.
Microphase Separation of Bulk and Ultrathin Films of Polyurethane Elastomers
Authors: Furukawa Mutsuhisa , Kojio Ken , Kugumiya So , Uchiba Yusuke , Mitsui Yoshitaka 
Published: July 2008

AbstractSurmmary: Polyurethane elastomers (PUEs) were synthesized with poly(oxytetramethylene) glycol (PTMG), 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butanediol (BD)/1,1,1‐trimethylol propane (TMP) by a prepolymer method. The degree of microphase separation of bulk and ultrathin films for these PUEs was confirmed by Fourier transform infrared (FT‐IR) spectroscopy, differential scanning calorimetry (DSC) and atomic force microscopy (AFM). In the bulk films, FT‐IR and DSC measurements revealed that the degree of micro‐phase separation strengthened with increasing BD content. AFM observation of the BD‐PUE showed hard segment domains surrounded by a soft segment matrix. The domains ranged in size from 10‐20 nm, while BD/TMP‐ and TMP PUEs did not have clear domains. On the other hand, AFM observation was carried out on thin films (200 mm in thickness) and ultrathin films (approximately 8‐5 nm) prepared by spin‐coating the different concentrations of PUE solutions. The microphase separated strucuture under 10 nm in thickness showed marked decreases in the size of the microphase‐separated domain.
Synthesis and Self‐Assembly of 2nd Generation Dendritic Homopolymers and Copolymers of Polydienes with Different Isomeric Microstructures
Authors: Avgeropoulos Apostolos , Rangou Sofia , Krikorian Vahik , Thomas Edwin L. 
Published: July 2008

AbstractSynthesis of 2nd generation dendritic polymeric materials via anionic polymerization procedures in combination with chlorosilane chemistry, consisting either from one polydienic segment (homopolymers) or from two chemically different polydienic components (copolymers), is described. The polydienes used were poly(butadiene) (PB) with ∼90% 1,4‐isomerism and poly(isoprene) (PI) with increased 3,4‐isomerism (∼60%). Molecular characterization of intermediate products and the final dendritic materials was made with Gel Permeation Chromatography (GPC), Membrane and Vapour Pressure Osmometry (MO and VPO respectively), Gas Chromatography –Mass Spectroscopy (GC‐MS) and 1H‐Nuclear Magnetic Resonance (1H‐NMR) Spectroscopy, leading to the conclusion that they can be considered model polymers. Morphological studies solely with Transmission Electron Microscopy (TEM) have been conducted on two of the four synthesized copolymer samples exhibiting microphase separation between the two polydiene segments.
Quantitative Characterization of the Structure of PP/Layered Silicate Nanocomposites at Various Length Scales
Authors: Dominkovics Zita , Renner Károly , Pukánszky Béla , Pukánszky Béla 
Published: July 2008

AbstractThe structure and rheological properties of a large number of layered silicate polypropylene nanocomposites were studied with widely varying compositions. Unlike general practice, morphology was characterized at different length scales covering several decades by SEM, TEM, and XRD. Rheological measurements supplied additional information about structure. The results showed that these materials possess a very complex structural architecture. The introduction of a functionalized polymer decreases the size of the original clay particles. However, relatively large silicate particles were found also in composite samples yielding XRD traces without silicate reflection. We found that not only two (individual layers, intercalated stacks), but four morphological entities, i.e. also particles and a silicate network, may be present simultaneously in the composites. An attempt was made to characterize morphology quantitatively, wherever possible. SEM and TEM micrographs were evaluated by image analysis, XRD traces by curve fitting, while a model was developed to determine relaxation time from rheological measurements, but only XRD and SEM results are reported here.
Mechanism of Thermal Degradation of an Inorganic‐Organic Hybrid Based on an Epoxy‐POSS
Authors: Montero Belén , Ramírez Carmen , Rico Maite , Torres Araceli , Cano Jesús , López Joaquín 
Published: July 2008

AbstractA novel inorganic‐organic hybrid material, belonging to the family of polyhedral oligomeric silsesquioxanes (POSS), was used to reduce the trend of a conventional epoxy‐amine system to undergo combustion. The mixtures with different percentages in weight of POSS, and equal number of equivalents between of epoxy and amino groups were tested by thermogravimetic analysis (TGA) in both, argon and oxygen atmospheres. The results indicated that the char/ceramic yield values increase with the content of POSS and therefore, fire resistance is enhanced. Activation energies of degradation processes were obtained by Kissinger‐Akahira‐Sunose method. An empirical kinetic model satisfactorily explained the degradation mechanism of different blends.