bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amyloid β peptide toxicity in differentiated PC12 cells: Calpain‐calpastatin, caspase, and membrane damage
Authors: Vaisid Tali , Kosower Nechama S. , Elkind Esther , Barnoy Sivia 
Published: April 2008

AbstractAmyloid β peptide (Aβ) is implicated in the pathogenesis of Alzheimer's disease (AD). The peptide is toxic to neurons, possibly by causing initial synaptic dysfunction and neuronal membrane dystrophy, promoted by increased cellular Ca2+. Calpain (Ca2+‐dependent protease) and caspase have also been implicated in AD. There is little information on communication between the two proteases or on the involvement of calpastatin (the specific calpain inhibitor) in Aβ toxicity. We studied the effects of Aβ25–35 (sAβ) on calpain, calpastatin, and caspase in neuronal‐like differentiated PC12 cells. sAβ‐treated cells exhibited primarily cell membrane damage (varicosities along neurites, enhanced membrane permeability to propidium iodide, without apparent nuclear changes of apoptosis, and little poly (ADP‐ribose) polymerase [PARP] degradation). The sAβ‐induced membrane damage is in contrast with staurosporine‐induced damage (nuclear apoptotic changes, PARP degradation, without membrane propidium iodide permeability). sAβ led to activation of caspase‐8 and calpain, promotion of calpastatin degradation (by caspase‐8 and by calpain), and enhanced degradation of fodrin (mainly by calpain). The results support the idea that Aβ causes primarily neuronal membrane dysfunction, and point to cross‐talk between calpain and caspase (protease activation and degradation of calpastatin) in Aβ toxicity. Increased expression of calpastatin and/or decrease in calpain and caspase‐8 may serve as means for ameliorating early symptoms of AD. © 2008 Wiley‐Liss, Inc.
Feedback acceptance in developmental assessment centers: the role of feedback message, participant personality, and affective response to the feedback session
Authors: Bell Suzanne T. , Arthur Winfred 
Published: April 2008

AbstractWe investigated feedback acceptance by participants (N = 141) in an operational developmental assessment center (AC). Consistent with predictions based on self‐enhancement theory and the Affective Infusion Model, results indicated that higher assessor ratings were associated with higher feedback acceptance, and this relationship was partially mediated by the participant's affective reaction to the feedback session. Participants' self‐ratings of their AC performance did not affect this relationship suggesting no support for our prediction based on self‐verification theory. We also investigated the role of participants' self‐ratings of agreeableness, extraversion, and emotional stability in feedback acceptance by testing specific moderated mediation hypotheses. Extraversion was related to feedback acceptance through the affective reaction to the feedback session. Agreeableness moderated the affective reaction to the feedback session and feedback acceptance relationship such that there was a strong relationship between affective reaction and feedback acceptance for highly agreeable participants, but no relationship for low agreeable individuals. For low agreeable individuals, there was a positive direct relationship between the assessor ratings and feedback acceptance which was not observed for highly agreeable individuals. The hypothesized role of emotional stability in predicting feedback acceptance was not supported. Implications for the delivery of feedback in developmental ACs are discussed in light of these findings. Copyright © 2008 John Wiley & Sons, Ltd.
Long work hours: a social identity perspective on meta‐analysis data
Authors: Ng Thomas W. H. , Feldman Daniel C. 
Published: April 2008

AbstractThe current study utilizes social identity theory to investigate employees' work hours. Specifically, we use meta‐analysis to examine the relationships between hours worked and indicators of organizational identity (e.g., organizational support and tenure), occupational identity (e.g., human capital investments and work centrality), and family identity (e.g., family responsibilities and family satisfaction). The meta‐analysis also allowed us to explore other important correlates of hours worked (e.g., situational demands, job performance, mental health, and physical health), moderating variables (e.g., age, gender, and job complexity), and curvilinear relationships of work hours to social identity indicators. Overall, we found that occupational factors and situational demands had the strongest relationships with hours worked, hours worked were negatively associated with measures of employee well‐being, gender had several significant moderating effects, and there were curvilinear relationships between hours worked and well‐being and work–family conflict variables. The article concludes with directions for future theoretical and empirical research. Copyright © 2008 John Wiley & Sons, Ltd.
Team conflict management and team effectiveness: the effects of task interdependence and team identification
Authors: Somech Anit , Desivilya Helena Syna , Lidogoster Helena 
Published: April 2008

AbstractThe present study explores the dynamics of conflict management as a team phenomenon. The study examines how the input variable of task structure (task interdependence) is related to team conflict management style (cooperative versus competitive) and to team performance, and how team identity moderates these relationships. Seventy‐seven intact work teams from high‐technology companies participated in the study. Results revealed that at high levels of team identity, task interdependence was positively associated with the cooperative style of conflict management, which in turn fostered team performance. Although a negative association was found between competitive style and team performance, this style of team conflict management did not mediate between the interactive effect of task interdependence and team identity on team performance. Copyright © 2008 John Wiley & Sons, Ltd.
Analytical methodologies for quantification of ferulic acid and its oligomers
Authors: Barberousse Hélène , Roiseux Olivier , Robert Christelle , Paquot Michel , Deroanne Claude , Blecker Christophe 
Published: April 2008

AbstractFerulic acid (4‐hydroxy‐3‐methoxycinnamic acid) is the most widespread hydroxycinnamic acid in the plant world, where it is a key molecule in cell wall architecture. Owing to its high antioxidant properties, ferulic acid shows large potential applications in food industry as well as in the health and cosmetic markets. There is thus a high interest in extracting this high‐value compound from waste materials of the agricultural industry, which requires the selection of an appropriate quantification method. This paper therefore gives an overview of analytical methodologies developed over past decades for quantification of ferulic acid and its oligomers. Copyright © 2008 Society of Chemical Industry
Impact of column temperature and mobile phase components on selectivity of hydrophilic interaction chromatography (HILIC)
Authors: Hao Zhigang , Xiao Baiming , Weng Naidong 
Published: April 2008

AbstractThe retention mechanism and chromatographic behavior for different polar analytes under hydrophilic interaction chromatography (HILIC) conditions have been studied by application of different mobile phases and stationary phases to various analytes at different temperatures. In addition to the commonly accepted mechanism of analyte liquid‐liquid partitioning between mobile phase and water‐enriched solvent layer which is partially immobilized onto the surface of the stationary phase, hydrogen‐bonding, hydrophobic interaction, and ion‐exchange interactions may also be involved. The predominant retention mechanism in HILIC separation is not always easily predictable. It can depend not only on the characteristics of the analytes but also on the selection of mobile and stationary phase compositions. The objective of this review is to evaluate the potential application of column temperature and mobile phase composition toward improving HILIC selectivity. The functional groups from analyte structures, stationary phase materials and organic mobile phase solvents will be highlighted.
Profiling of N‐ and O‐glycopeptides of erythropoietin by capillary zwitterionic type of hydrophilic interaction chromatography/electrospray ionization mass spectrometry
Authors: Takegawa Yasuhiro , Ito Hiroki , Keira Takuro , Deguchi Kisaburo , Nakagawa Hiroaki , Nishimura Shin‐Ichiro 
Published: April 2008

AbstractCapillary zwitterionic‐type hydrophilic interaction chromatography (ZIC‐HILIC)/ESI‐MS has been applied to the Glu‐C digest of recombinant human erythropoietin (rhEPO) expressed in Chinese hamster ovary (CHO) cells. N‐Glycopeptides (105) and O‐glycopeptides (8) were detected in a single run of the capillary ZIC‐HILIC/ESI‐MS analysis. Among them, N‐acetyl‐neuraminic acids (Neu5Ac) of N‐ and O‐glycans were partially acetylated and some were replaced with N‐glycoyl‐neuraminic acid (Neu5Gc). Their retentions in the ZIC‐HILIC separation can be explained to some extent with the degree of acetylation and N‐glycoylation, both of which influence the hydrophilicity/hydrophobicity of the N‐ and O‐glycan moieties of glycopeptides.
The discovery of antiviral agents: Ten different compounds, ten different stories
Authors: De Clercq Erik 
Published: April 2008

AbstractThis review article, while autobiographical to some extent, describes the discovery of ten (classes of) antiviral compounds that have made (or just did not make) it to the market for the therapy of viral infections, but each in its own way influenced the landscape of our dealing with virus infections: (i) valaciclovir, (ii) BVDU, (iii) DHPA, (iv) cidofovir, (v) adefovir, (vi) tenofovir, (vii) stavudine, (viii) HEPT, (ix) TIBO, and (x) AMD3100. Successful drug development, as is certainly true for antiviral drugs and exemplified for the acyclic nucleoside phosphonates cidofovir, adefovir and tenofovir, requires patience and perseverance, and a close continuous and dedicated interaction between Chemistry, Biology/Medicine and Industry. © 2008 Wiley Periodicals, Inc. Med Res Rev, 28, No. 6, 929–953, 2008
Expression of selenium‐binding protein 1 characterizes intestinal cell maturation and predicts survival for patients with colorectal cancer
Authors: Li Tianhong , Yang Wancai , Li Maomi , Byun Do‐Sun , Tong Chang , Nasser Shannon , Zhuang Min , Arango Diego , Mariadason John M. , Augenlicht Leonard H. 
Published: April 2008

AbstractTo identify candidate genes involved in the development of colorectal cancer, we used cDNA microarrays to analyze gene expression differences between human colorectal tumors and paired adjacent normal mucosa. We identified ∼︁3.5‐fold significant downregulation of selenium‐binding protein 1 (SBP1) in colorectal tumors compared to normal mucosa (p = 0.003). Importantly, stage III colorectal cancer patients with low tumor‐SBP1 expression had significantly shorter disease‐free and overall survival as compared with those patients with high tumor‐SBP1 expression (p = 0.04 and 0.03, respectively). We further characterized the role of SBP1 in colorectal cancer in vivo and in vitro. In normal tissue, SBP1 was maximally expressed in terminally differentiated epithelial cells on the luminal surface of crypts in the large intestine. Consistent with this in vivo localization, SBP1 was upregulated during in vitro colonic cell differentiation along the absorptive (Caco‐2) and secretory (HT29 Clones 16E and 19A) cell lineages. Downregulation (approximately 50%) of SBP1 expression by small interfering RNA in colonic cancer cells was associated with reduced expression of another epithelial differentiation marker, carcinoembryonic antigen (CEA), although PCNA and p21WAF1/cip1 expression were not altered. These data demonstrate that higher expression of SBP1 is associated with differentiation of the normal colonic epithelia and may be a positive prognostic factor for survival in stage III colorectal carcinoma.
Tannin 1‐α‐O‐galloylpunicalagin induces the calcium‐dependent activation of endothelial nitric‐oxide synthase via the phosphatidylinositol 3‐kinase/Akt pathway in endothelial cells
Authors: Chen Lih‐Geeng , Liu Yen‐Chin , Hsieh Chia‐Wen , Liao Being‐Chyuan , Wung Being‐Sun 
Published: April 2008

AbstractMany polyphenols have been found to increase endothelial nitric oxide (NO) production. In our present study, we investigated the effects of 1‐α‐O‐galloylpunicalagin upon endothelial nitric oxide synthase (eNOS) activity in endothelial cells (ECs). Both 1‐α‐O‐galloylpunicalagin and punicalagin induced NO production in a dose‐dependent manner in ECs. Despite having similar chemical structures, punicalagin induced lower levels of NO production than 1‐α‐O‐galloylpunicalagin. After 1‐α‐O‐galloylpunicalagin addition, a rise in the intracellular Ca2+ concentration preceded NO production. The Ca2+ ionophore A23187 stimulated eNOS phosphorylation and augmented NO production. Pretreatment with Ca2+ chelators inhibited 1‐α‐O‐galloylpunicalagin‐induced eNOS phosphorylation and NO production. Treatment with 1‐α‐O‐galloylpunicalagin did not alter the eNOS protein levels but, unlike punicalagin, induced a sustained activation of eNOS Ser1179 phosphorylation. 1‐α‐O‐galloylpunicalagin was also found to activate ERK1/2, JNK and Akt in ECs. Moreover, simultaneous treatment of these cells with specific phosphatidylinositol‐3‐kinase inhibitors significantly inhibited the observed increases in eNOS activity and phosphorylation levels. In contrast, the inhibition of (ERK)1/2, JNK and p38 had no influence on eNOS Ser1179 phosphorylation. Our present results thus indicate that the 1‐α‐O‐galloylpunicalagin‐induced calcium‐dependent activation of eNOS is primarily mediated via a phosphatidylinositol 3‐kinase/Akt‐dependent increase in eNOS activity, and occurs independently of the eNOS protein content.
Geraniin‐mediated apoptosis by cleavage of focal adhesion kinase through up‐regulation of Fas ligand expression in human melanoma cells
Authors: Lee Jang‐Chang , Tsai Chih‐Yen , Kao Jung‐Yie , Kao Ming‐Ching , Tsai Shih‐Chang , Chang Chih‐Shiang , Huang Li‐Jiau , Kuo Sheng‐Chu , Lin Jen‐Kun , Way Tzong‐Der 
Published: April 2008

AbstractGeraniin, a form of tannin separated from geranium, causes cell death through induction of apoptosis; however, cell death characteristics for geraniin have not yet been elucidated. Here, we investigated the mechanism of geraniin‐induced apoptosis in human melanoma cells and demonstrated that geraniin was able to induce cell apoptosis in a concentration‐ and time‐dependent manner. We also examined the signaling pathway related to geraniin‐induced apoptosis. To clarify the relationship between focal adhesion kinase (FAK) and geraniin‐induced apoptosis, we treated human melanoma cells with geraniin and found that this resulted dose‐ and time‐dependent degradation in FAK. However, FAK cleavage was significantly inhibited when cells were pretreated with a selective inhibitor of caspase‐3 (Ac‐Asp‐Glu‐Val‐Asp‐CHO). Here, we demonstrated for the first time that geraniin triggered cell death by caspase‐3‐mediated cleavage of FAK. There were two possible mechanisms for activating caspase‐3, mitochondria‐mediated and receptor‐mediated apoptosis. To confirm the geraniin‐relevant signaling pathway, using immunoblot analysis we found that geraniin‐induced apoptosis was associated with the up‐regulation of Fas ligand expression, the activation of caspase‐8, the cleavage of Bid, and the induction of cytochrome c release from mitochondria to the cytosol. Treatment with geraniin caused induction of caspase‐3 activity in a dose‐ and time‐dependent manner followed by proteolytic cleavage of poly‐(ADP‐ribose) polymerase, and DNA fragmentation factor 45. The geraniin‐induced apoptosis may provide a pivotal mechanism for its cancer‐chemopreventive action.
White‐light emission from mixing blue and red‐emitting metal complexes
Authors: Shunmugam Raja , Tew Gregory N. 
Published: April 2008

AbstractCombining polymeric architectures with metal ions produces hybrid materials with extremely rich properties. We have been studying polymers containing terpyridine in the side chain. This report discusses a novel white‐light emission from a two‐emitter system comprising a blue‐emitting dysprosium‐chelated polymer and a red‐emitting ruthenium complex. The polymer architecture easily allows the incorporate of blue color into the material and provides a matrix which leads to the facile production of truly white light. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of fly ash silica and precipitated silica fillers on the viscosity, cure, and viscoelastic properties of natural rubber
Authors: Thongsang S. , Sombatsompop N. , Ansarifar A. 
Published: April 2008

AbstractThe viscosity, cure properties, storage, and loss moduli and tan δ of natural rubber (NR) filled with the same amounts of precipitated silica (PSi) and fly ash silica (FASi) fillers were measured. The fillers were treated with bis[3‐triethoxysilylpropyl‐]tetrasulfide (TESPT), or, used in the rubber untreated. TESPT is a sulfur‐containing bi‐functional organosilane that chemically adheres silica to rubber and also prevents silica from interfering with the reaction mechanism of sulfur cure. The dispersion of PSi and FASi in the rubber was investigated using scanning electron microscope (SEM). The effects of silica type and loading and surface treatment on the aforementioned properties were of interest. The SEM results showed that the FASi particles were larger in size and had a wider particle size distribution when compared with the PSi particles. The viscosity of the compounds decreased progressively with mixing time, and the compounds with FASi had a lower viscosity than those filled with PSi. The treatment with Si69 had no beneficial effect on the dispersion of the fillers in the rubber matrix. At low temperatures, the type and loading of the filler had no effect on the storage and loss moduli of the compounds, but the effect was more pronounced at high temperatures. There was also evidence from the tan δ and glass transition temperature (Tg) measurements that some limited interaction between the filler particles and rubber had occurred because of TESPT. Copyright © 2008 John Wiley & Sons, Ltd.
Structure and properties of polypropylene/clay nanocomposites compatibilized by solid‐phase grafted polypropylene
Authors: Ding Chao , He Hui , Guo Baochun , Jia Demin 
Published: April 2008

AbstractPolypropylene/organic‐montmorillonite (PP/OMMT) nanocomposites were prepared via a solid‐phase PP graft (TMPP) with a higher grafting level as the compatibilizer. The effects of the compatibilizer on the structure and properties of PP/OMMT nanocomposites were investigated. The structure of the nanocomposites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that when the weight ratio of TMPP and OMMT is greater than 1:1, the OMMT can be dispersed in PP matrix uniformly at the nanoscale. The mechanical properties of the nanocomposites reached a maximum when the weight ratio of TMPP and OMMT is 1:1, although more uniform dispersion was achieved at a higher content of TMPP. The mechanical properties of the nanocomposites decrease with the content of TMPP. The crystallization behavior, dynamic rheological property, and thermal stability of the nanocomposites were investigated by differential scanning calorimetry (DSC), dynamic rheological analysis, and thermal gravimetric analysis (TGA), respectively. Due to the synergistic effects of TMPP and OMMT on the crystallization of PP, the crystallization peak temperature of the nanocomposites increased remarkably compared with that of the neat PP. TMPP shows β‐phase nucleating ability and OMMT promotes the development of β‐phase crystallite. The nanocomposites show restricted melt flow and enhanced temperature sensitivity compared with the neat PP. The thermal stability of the nanocomposites is obviously improved compared with that of the neat PP. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.
Analysis of galanthamine‐type alkaloids by capillary gas chromatography–mass spectrometry in plants
Authors: Berkov Strahil , Bastida Jaume , Viladomat Francesc , Codina Carles 
Published: April 2008

AbstractGalanthamine, an acetylcholinesterase inhibitor used for the treatment of Alzheimer's disease, and galanthamine‐type alkaloids are synthesised in different plants of the family Amaryllidaceae. A capillary gas chromatographic–mass spectroscopic (CGC‐MS) method for the separation of 7 galanthamine type alkaloids, including galanthamine and epigalanthamine, is described in the present paper. A simple method for the routine quantification of galanthamine in plants was developed using pre‐packed columns with diatomaceous earth (Isolute HM‐N), allowing simultaneous preparation of a large number of samples. Galanthamine showed excellent linearity in the range from 50 to 1000 µg/mL and the limit of quantification was 5 µg/mL in total ion current mode and 1.6 ng/mL in selected ion monitoring mode. The recovery of galanthamine was more than 90%. Interday reproducibility (RSD) of the extraction was 2.74%. A method to find and to microextract Amaryllidaceae alkaloids in low‐mass plant samples is also described. Copyright © 2008 John Wiley & Sons, Ltd.
Preparative separation of the saponin lancemaside a from Codonopsis lanceolata by centrifugal partition chromatography
Authors: Shirota Osamu , Nagamatsu Kumi , Sekita Setsuko , Komoto Noriko , Kuroyanagi Masanori , Ichikawa Makoto , Ohta Sanae , Ushijima Mitsuyasu 
Published: April 2008

AbstractIntroduction. Lancemaside A is a saponin that inhibits decreases in blood testosterone level and thus prevents or ameliorates symptoms associated with male climacteric disorder. Our initial attempt to preparative isolation of lancemaside A from the saponin fraction of Codonopsis lanceolata roots by a preparative HPLC did not give a clear result.Objective. To develop a simple and efficient method for the preparative isolation of lancemaside A from the hot water extract of C. lanceolata roots using centrifugal partition chromatography (CPC).Methodology. The saponin fraction obtained from the hot water extract of C. lanceolata roots was used as the sample for preparative‐scale separation of lancemasides by CPC using n‐hexane:n‐butanol:methanol:0.1% aqueous formic acid (3:4:1:6, v/v) as the two‐phase solvent system. The upper phase (organic phase) of the two‐phase solvent system was used as the mobile phase, and 0.5 g of saponin fraction was applied for separation by CPC. Each fraction that was separated by CPC was analysed by HPLC, and the fractions containing each of the separated compounds were pooled together, and then were purified by simple preparative HPLC.Results. The demonstrated separation sequence, hot water extraction, DIAION HP‐20 column chromatography, CPC and preparative HPLC, yielded lancemaside A, foetidissimoside A and astersaponin Hb in their pure forms.Conclusion. The simple and efficient method for the preparative isolation of lancemaside A along with two other saponins, foetidissimoside A and astersaponin Hb, from the saponin fraction of C. lanceolata was established using CPC.