bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of tribological and mechanical properties of PTFE composites filled with surface treated K2Ti6O13 whisker
Authors: Shi Yijun , Mu Liwen , Feng Xin , Lu Xiaohua
Published: October 2011

K2Ti6O13 whisker was modified with n‐octadecyltrichlorosilane (OTS), fluorosurfactant (FSK), and silane coupling agent (KH‐550), respectively. The surface energy of K2Ti6O13 whisker was calculated based on Van Oss‐Chaudhury‐Good function. Then the influence of surface modification on the tribological and mechanical properties of K2Ti6O13 whisker filled polytetrafluoroethylene (PTFE) composites was studied. Surface energy calculation shows that the surface energy of OTS‐treated K2Ti6O13 whisker is only 29.0 mJ/m2, which is the closest to the value of pure PTFE. Among all samples, the PTFE composite filled with OTS‐treated K2Ti6O13 whisker shows the best antiwear property, tensile strength, and impact strength, which is about 19 to 33%, 15 and 55% higher than that of untreated K2Ti6O13 whisker filled PTFE, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Modifying montmorillonite clay via silane grafting and interfacial polycondensation for melt compounding of nylon‐66 nanocomposite
Authors: Salehi‐Mobarakeh Hamid , Yadegari Ali , Khakzad‐Esfahlan Fahimeh , Mahdavian Alireza
Published: October 2011

A trifunctional organo alkoxysilane (3‐aminopropyl)triethoxysilane (γ‐APS) has been used as reagent for the chemical modification of montmorillonite clay. Silane grafting was taken place in dry and hydrolyzing conditions. Silane grafted and pristine clay took part in interfacial polycondensation process to deposit a layer of nylon‐66 onto the clay lamellae and therefore, enhance their affinity with nylon‐66 matrix. Evidence of presence of grafted silane molecules and deposition of nylon‐66 on clay particles were provided by Fourier transform‐infrared, thermogravimetric analysis (TGA), and X‐ray diffraction (XRD). Such modified clays and pristine clays were melt compounded with nylon‐66. The structures of the resulting nylon composites were characterized using XRD and transmission electron microscopy and the results showed presence of both intercalation and exfoliation. TGA thermograms of nanocomposites indicated improved thermal stability upon the incorporation of silane grafted montmorillonite. Furthermore, differential scanning calorimetry scans showed that silane modified clays promoted crystallization in nanocomposites. Increase of storage modulus and depression of tan δ peak in nanocomposites in dynamical mechanical thermal analysis were observed. The rheological properties of nylon‐66 and nanocomposites were also evaluated and differences in values of complex viscosity of samples were noticed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Comparative study on natural antioxidant as an aging retardant for natural rubber vulcanizates
Authors: Komethi M. , Othman N. , Ismail H. , Sasidharan S.
Published: October 2011

The research aim is mainly to investigate the effectiveness of natural antioxidant (NA) obtained from oil palm leaves (Elaeis guineensis) as an aging retardant in natural rubber (NR) vulcanizates. Comparison of NA with other commercial antioxidants, trimethyl quinoline (TMQ) and butylated hydroxy toluene (BHT), is investigated. The effect of natural and commercial antioxidants on NR vulcanizates was explored before and after aging. Aging test was carried out at 70°C for three different periods, 4, 7, and 14 days to determine aging property by performing the tensile and tear tests. NA shows lower tensile properties, crosslink density, tack strength but high tear strength compared to the commercial antioxidants, BHT and TMQ. However, upon aging NR vulcanizates with NA retains its properties equivalent to that of commercial antioxidants, BHT and TMQ. Thus, NA can be used as an aging retardant for short‐term protection in application requiring moderate tensile properties and can be used as alternative source for commercial antioxidant. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Invertebrate models of spinal muscular atrophy: Insights into mechanisms and potential therapeutics
Authors: Grice Stuart J. , Sleigh James N. , Liu Ji‐Long , Sattelle David B.
Published: October 2011

Invertebrate genetic models with their tractable neuromuscular systems are effective vehicles for the study of human nerve and muscle disorders. This is exemplified by insights made into spinal muscular atrophy (SMA) using the fruit fly Drosophila melanogaster and the nematode worm Caenorhabditis elegans. For speed and economy, these invertebrates offer convenient, whole‐organism platforms for genetic screening as well as RNA interference (RNAi) and chemical library screens, permitting the rapid testing of hypotheses related to disease mechanisms and the exploration of new therapeutic routes and drug candidates. Here, we discuss recent developments encompassing synaptic physiology, RNA processing, and screening of compound and genome‐scale RNAi libraries, showcasing the importance of invertebrate SMA models.

Editor's suggested further reading in BioEssays: SMN and Gemins: ‘We are family’ ... or are we? Abstract
Analysis of transcriptomic and proteomic profiles demonstrates improved Madin–Darby canine kidney cell function in a renal microfluidic biochip
Authors: Snouber Leila Choucha , Letourneur Franck , Chafey Philippe , Broussard Cedric , Monge Matthieu , Legallais Cécile , Leclerc Eric
Published: October 2011

We have evaluated the influence of the microfluidic environment on renal cell functionality. For that purpose, we performed a time lapse transcriptomic and proteomic analysis in which we compared gene and protein expressions of Madin–Darby canine kidney cells after 24 h and 96 h of culture in both microfluidic biochips and plates. The transcriptomic and proteomic integration revealed that the ion transporters involved in calcium, phosphate, and sodium homoeostasis and several genes involved in H+ transporters and pH regulation were up‐regulated in microfluidic biochips. Concerning drug metabolism, we found Phase I (CYP P450), Phase II enzymes (GST), various multidrug resistance genes (MRP), and Phase III transporters (SLC) were also up‐regulated in the biochips. Furthermore, the study shows that those inductions were correlated with the induction of the Ahr and Nrf‐2 dependent pathways, which results in a global cytoprotective response induced by the microenvironment. However, there was no apoptosis situation or cell death in the biochips. Microfluidic biochips may thus provide an important insight into exploring xenobiotic injury and transport modifications in this type of bioartificial microfluidic kidney. Finally, the investigation demonstrated that combining the transcriptomic and proteomic analyses obtained from a cell “on chip” culture would provide a pertinent new tool in the mechanistic interpretation of cellular mechanisms for predicting kidney cell toxicity and renal clearance in vitro. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Synthesis, Characterization, Thermal Behavior, and DNA‐Cleaving Studies of Cyano‐Bridged Nickel(II)Copper(II) Complexes of 4‐(Pyridin‐2‐ylazenyl)resorcinol
Authors: Karipcin Fatma , Özmen İsmail , Cülü Burcin , Çelikoğlu Umut
Published: October 2011

We present here the syntheses of a mononuclear CuII complex and two polynuclear CuIINiII complexes of the azenyl ligand, 4‐(pyridin‐2‐ylazenyl)resorcinol (HL; 1). The reaction of HL (1) and copper(II) perchlorate with KCN gave a mononuclear complex [CuL(CN)] (4). Using 4, one pentanuclear complex, [{CuL(NC)}4Ni](ClO4)2 (5) and one trinuclear complex, [{CuL(CN)}2NiL]ClO4 (6), were prepared and characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, and thermal analysis. Stoichiometric and spectral results of the mononuclear CuII complex indicated that the metal/ligand/CN ratio was 1 : 1 : 1, and the ligand behaved as a tridentate ligand forming neutral metal chelates through the pyridinyl and azenyl N‐, and resorcinol O‐atom. The interaction between the compounds (the ligand 1, its NiII and CuII complexes without CN, i.e., 2 and 3, and its complexes with CN, 4–6) and DNA has also been investigated by agarose gel electrophoresis. The pentanuclear Cu4Ni complex (5) with H2O2 as a co‐oxidant exhibited the strongest DNA‐cleaving activity.
Synthesis of Novel Derivatives of Esculentoside A and Its Aglycone Phytolaccagenin, and Evaluation of Their Haemolytic Activity and Inhibition of Lipopolysaccharide‐Induced Nitric Oxide Production
Authors: Gong Wei , Jiang Zhihui , Sun Peng , Li Ling , Jin Yongsheng , Shao Lucheng , Zhang Wen , Liu Baoshu , Zhang Hongwei , Tang Hua , Chen Yufeng , Yi Yanghua , Zhang Dazhi
Published: October 2011

A series of 46 compounds derived from esculentoside A and its aglycone were synthesized and characterized. The effect of these compounds on lipopolysaccharide (LPS)‐induced NO production, haemolytic activity, and cell viability was evaluated. Structureactivity relationship was established by comparing the derivatives of esculentoside A with its aglycone derivatives. Both the aglycone and its derivatives showed higher inhibitory effects on LPS‐induced NO production, and lower haemolytic activities than esculentoside A and its derivatives.
Chemical Diversity in the Essential Oil of Indian Valerian (Valeriana jatamansiJones)
Authors: Verma Ram S. , Verma Rajesh K. , Padalia Rajendra C. , Chauhan Amit , Singh Anand , Singh Hemendra P.
Published: October 2011

To explore the diversity in the essential oil yield and composition of Valeriana jatamansi Jones (syn. V. wallichii DC) growing wild in Uttarakhand (Western Himalaya), 17 populations were collected from different locations and grown under similar conditions. Comparative results showed considerable variations in the essential oil yield and composition. The essential oil yield varied from 0.21 to 0.46% in the fresh roots and rhizomes of different populations of V. jatamansi. Analysis of the essential oils by GC (RI) and GC/MS and the subsequent classification by principal component analysis (PCA) resulted in six clusters with significant variations in their terpenoid composition. Major components in the essential oils of the different populations were patchouli alcohol (1; 13.4–66.7%), α‐bulnesene (3; <0.05–23.5%), α‐guaiene (4; 0.2–13.3%), guaiol (5; <0.05–12.2%), seychellene (6; 0.2–9.9%) viridiflorol (<0.05–7.3%), and β‐gurjunene (7; 0.0–7.1%). V. jatamansi populations with contents of 1 higher than 60% may be utilized commercially in perfumery.
Tridentate N‐Donor Palladium(II) Complexes as Efficient Coordinating Quadruplex DNA Binders
Authors: Largy Eric , Hamon Florian , Rosu Frédéric , Gabelica Valérie , De Pauw Edwin , Guédin Aurore , Mergny Jean‐Louis , Teulade‐Fichou Marie‐Paule
Published: October 2011

Fifteen complexes of palladium, platinum, and copper, featuring five different N‐donor tridentate (terpyridine‐like) ligands, were prepared with the aim of testing their G‐quadruplex–DNA binding properties. The fluorescence resonance energy transfer melting assay indicated a striking positive effect of palladium on G‐quadruplex DNA stabilization compared with platinum and copper, as well as an influence of the structure of the organic ligand. Putative binding modes (noncoordinative π stacking and base coordination) of palladium and platinum complexes were investigated by ESI‐MS and UV/Vis spectroscopy experiments, which all revealed a greater ability of palladium complexes to coordinate DNA bases. In contrast, platinum compounds tend to predominantly bind to quadruplex DNA in their aqua form by noncoordinative interactions. Remarkably, complexes of [Pd(ttpy)] and [Pd(tMebip)] (ttpy=tolylterpyridine, tMebip=2,2′‐(4‐p‐tolylpyridine‐2,6‐diyl)bis(1‐methyl‐1H‐benzo[d]imidazole)) coordinate efficiently G‐quadruplex structures at room temperature in less than 1 h, and are more efficient than their platinum counterparts for inhibiting the growth of cancer cells. Altogether, these results demonstrate that both the affinity for G‐quadruplex DNA and the binding mode of metal complexes can be modulated by modifying either the metal or the organic ligand.
Synthetic Fuels from Natural Gas and Biomass – Status and Perspectives
Authors: Schaub Georg , Edzang Régis
Published: October 2011

Flüssige Energieträger leisten in Form von Kraft‐ und Treibstoffen sowie Heizstoffen mit ca. 38 % der Sekundärenergieträger einen wichtigen Beitrag zur heutigen Energieversorgung, hauptsächlich in den Bereichen Verkehr und Gebäudeheizung. Sie werden auch zukünftig benötigt werden, auch wenn der Heizbedarf in Gebäuden zurückgehen wird und elektrische Antriebe im PKW‐Bereich wichtiger werden. Grund dafür ist die hohe Energiedichte, die vor allem bei einem mobilen Energieeinsatz wichtig ist. Der heute meist verwendete fossile Rohstoff Erdöl kann aufgrund von Preisanstieg, Versorgungssicherheit und CO2‐Emissionen zunehmend ergänzt und ersetzt werden. Der Beitrag fasst die neueren Entwicklungen zur Erzeugung von Erdöl‐Ersatzprodukten in Form von synthetischen Kraftstoffen aus Erdgas und Biomasse zusammen. Die Zukunftsaussichten werden mithilfe der Kriterien Chemie und Prozesstechnik, Energieeffizienz und Erzeugungskosten bewertet.
Strictly Anaerobic Batch Cultivation of Eubacterium ramulus in a Novel Disposable Bag Reactor System
Authors: Jonczyk Patrick , Schmidt Anne , Bice Ismet , Gall Mechthild , Gross Egon , Hilmer Jens‐Michael , Bornscheuer Uwe , Beutel Sascha , Scheper Thomas
Published: October 2011

Das anaerobe gastrointestinale Bakterium Eubacterium ramulus wurde erstmals in einem Einweg‐Beutelreaktorsystem mit 10 L Kulturmedium kultiviert. Im Vergleich zu Standard‐Flaschenkultivierungen mit Hungate‐Technik wurde um den Faktor 25 aufskaliert und die optische Dichte konnte um mehr als das 5fache gesteigert werden. Bei einer 10‐L‐Batch‐Kultivierung im Einweg‐Beutelreaktorsystem wurden 60 bis 70 g Feuchtzellmasse produziert. Zum Vergleich wurde eine 10‐L‐Batch‐Kultivierung in einem Edelstahlrührkessel durchgeführt, die ähnliche Ergebnisse wie das Beutelreaktorsystem hinsichtlich der Feuchtzellmasse und der optischen Dichte zeigte.
Chemical Characterization of Carbonated Natural Mineral Waters Produced in Turkey: Compliance with European Water Quality Standards
Authors: Güler Cüneyt , Alpaslan Musa
Published: October 2011

In this study, a total of 100 samples from 25 brands of carbonated natural mineral waters (CNMWs) produced in Turkey were analyzed for a total of 36 water quality constituents to determine their suitability for human consumption. Parameters examined include pH, electrical conductivity, ammonia, nitrate, nitrite, sulfate, sulfite, orthophosphate, chloride, fluoride, bicarbonate, and 25 major/trace elements analyzed by inductively coupled plasma‐mass spectrometry (ICP‐MS). The presence of these constituents in this type of water was investigated considering recent concerns about their quality and the lack of trace element information on the manufacturer labels. The analytical results obtained in this study were compared to the European Union (EU) norms, labeled values on bottles, as well as values from the literature. Results of this study have shown that Turkish CNMWs may contain high concentrations of sulfite, which is a known allergen, especially for chronic asthmatic population. CNMWs surveyed in this study have also appreciable amounts of fluoride (>1.5 mg L−1) that may have detrimental effects on health of children. The EU standards for As, Ba, Mn, and Ni were exceeded in seven CNMWs classified as “high mineral”. Compared to similar type of bottled waters from Europe and North America, CNMWs from Turkey generally contained higher elemental concentrations.
Toxicological Effects Induced by Cadmium in Gills of Manila Clam Ruditapes philippinarum Using NMR‐Based Metabolomics
Authors: Zhang Linbao , Liu Xiaoli , You Liping , Zhou Di , Yu Junbao , Zhao Jianmin , Feng Jianghua , Wu Huifeng
Published: October 2011

Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 µg L−1) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 µg L−1) and high (40 µg L−1) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR‐based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator.
Know when to run, know when to hide: can behavioral differences explain the divergent invasion success of two sympatric lizards?
Authors: Chapple David G. , Simmonds Sarah M. , Wong Bob B.M.
Published: October 2011

Invasive species represent a select subset of organisms that have successfully transitioned through each stage of the introduction process (transportation, establishment, and spread). Although there is a growing realization that behavior plays a critical role in invasion success, few studies have focused on the initial stages of introduction. We examined whether differences in the grouping tendencies and exploratory behavior of two sympatric lizard species could contribute to their divergent invasion success. While the nondirected activity of the two species did not differ, the invasive delicate skink (Lampropholis delicata) was found to be more exploratory than the congeneric noninvasive garden skink (L. guichenoti), which enabled it to more effectively locate novel environments and basking site resources. The delicate skink also exhibited a greater tendency to hide, which may act to enhance its probability of ensnarement in freight and cargo and decrease its likelihood of detection during transit. The grouping tendencies of the two species did not differ. Together, our results suggest that while the two species have an equivalent “opportunity” for unintentional human‐assisted transportation, several pre‐existing behavioral traits may enhance the success of the delicate skink in negotiating the initial stages of the introduction process, and subsequent post‐establishment spread.
Macrophages in human colorectal cancer are pro‐inflammatory and prime T cells towards an anti‐tumour type‐1 inflammatory response
Authors: Ong Siew‐Min , Tan Yann‐Chong , Beretta Ottavio , Jiang Dongsheng , Yeap Wei‐Hseun , Tai June J. Y. , Wong Wing‐Cheong , Yang Henry , Schwarz Herbert , Lim Kiat‐Hon , Koh Poh‐Koon , Ling Khoon‐Lin , Wong Siew‐Cheng
Published: October 2011

High macrophage infiltration into tumours often correlates with poor prognoses; in colorectal, stomach and skin cancers, however, the opposite is observed but the mechanisms behind this phenomenon remain unclear. Here, we sought to understand how tumour‐associated macrophages (TAMs) in colorectal cancer execute tumour‐suppressive roles. We found that TAMs in a colorectal cancer model were pro‐inflammatory and inhibited the proliferation of tumour cells. TAMs also produced chemokines that attract T cells, stimulated proliferation of allogeneic T cells and activated type‐1 T cells associated with anti‐tumour immune responses. Using colorectal tumour tissues, we verified that TAMs in vivo were indeed pro‐inflammatory. Furthermore, the number of tumour‐infiltrating T cells correlated with the number of TAMs, suggesting that TAMs could attract T cells; and indeed, type‐1 T cells were present in the tumour tissues. Patient clinical data suggested that TAMs exerted tumour‐suppressive effects with the help of T cells. Hence, the tumour‐suppressive mechanisms of TAMs in colorectal cancer involve the inhibition of tumour cell proliferation alongside the production of pro‐inflammatory cytokines, chemokines and promoting type‐1 T‐cell responses. These new findings would contribute to the development of future cancer immunotherapies based on enhancing the tumour‐suppressive properties of TAMs to boost anti‐tumour immune responses.
Direct Synthesis and Mass Spectroscopic Observation of the {M40} Polyoxothiometalate Wheel
Authors: Miras Haralampos N. , Zang Hong Ying , Long De‐Liang , Cronin Leroy
Published: October 2011

The nanosized, 2.2 nm, {Mo40} oxo(thio)metalate wheel was isolated in high yield using a direct synthetic procedure which involves acidification of a molybdate solution in the presence of the {Mo2O2S2}2+oxothio cation as the starting material. The [(Mo8O28)4(Mo2O2S2)4]24– wheel, 1a, was characterised by single‐crystal X‐ray diffraction analysis, IR, Raman, UV/Vis and flame atomic absorption spectroscopy (FAAS). Solid state and solution Raman spectroscopic studies allowed the unambiguous determination of the critical conditions by which compound 1 retains its integrity in solution. Electrospray ionisation mass spectrometry (ESI‐MS) studies carried out on aqueous solutions of the crystalline material showed that the nanosized wheel retains its integrity in concentrated solutions. High resolution ESI‐MS studies allowed the direct observation of the discrete wheel as well as the distinct self‐assembly stages of its formation; from the fundamental building units through to the final formation of well resolved aggregations of 1D chains which is in agreement with the solid state studies.
Separation of squalene from olive oil deodorizer distillate using supercritical fluids
Authors: Akgün Nalan A.
Published: October 2011

In this study, an integrated strategy using supercritical fluids for extraction of squalene from olive oil deodorizer distillate (OODD), one of the most important by‐products of the olive oil refining process is presented. First, OODD was esterified in supercritical methanol, and then squalene was extracted from the sample consisting of 66% methyl ester using supercritical CO2. The extraction conditions, i.e., pressure (88.2–121.8 bar), temperature (41.6–58.4°C) and extraction time (129.6–230.4 min), were optimized via RSM to achieve the highest squalene content. The optimal results were obtained at a temperature of 52.05°C, pressure of 104.8 bar and extraction time of 180 min. Consequently, two kinds of value‐added products such as biodiesel (up to 96% FAME, in extract) and olive squalene (up to 75%, in raffinate) were produced in shorter processing times when compared with distillation results of 70 h.

Practical applications: Traditionally, squalene is extracted from liver oil of rare deep‐sea sharks. Here we present the recovery of vegetal squalene in high purity from OODD. Our approach also presents a simple, reliable, and mobile solution. Squalene is widely used in cosmetics as a protective agent and natural moisturizer and as an adjuvant in influenza vaccines.
Determination of 3‐MCPD esters in edible oil – methods of analysis and comparability of results
Authors: Karasek Lubomir , Wenzl Thomas , Ulberth Franz
Published: October 2011

The discovery of fatty acid esters of 3‐chloropropane‐1,2‐diol (3‐MCPD) in edible oil products initiated food monitoring campaigns in many EU Member States. As the determination of 3‐MCPD esters was new to most laboratories, questions on the reliability of the produced analysis data were raised. In response to this, the Institute for Reference Materials and Measurements (IRMM) of the European Commission's Joint Research Centre (JRC) organised a proficiency test on the determination of 3‐chloropropane‐1,2‐diol esters (3‐MCPD esters) in edible oils. The aim of this proficiency test was to scrutinise the capabilities of official food control laboratories, private food control laboratories as well as laboratories from food industry to determine the 3‐MCPD esters content of edible oils. The study was carried out in accordance with “The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories” and ISO Guide 43. The test materials dispatched to the participants were: refined palm oil, extra virgin olive oil spiked with 3‐chloropropane‐1,2‐dioleate and 3‐MCPD standard solution in sodium chloride. Altogether 41 laboratories from 11 EU Member States, Switzerland and Macedonia subscribed for participation in the study. The analysis task was to determine the 3‐MCPD esters content as total 3‐MCPD content of the test samples. Participants were free to choose their analysis methods. In total, 34 laboratories reported results to the organisers of the study. The performance of laboratories in the determination of 3‐MCPD esters in edible oils was expressed by z‐scores. About 56% of the participants performed satisfactorily in the determination of 3‐MCPD esters in palm oil and 85% for the spiked extra virgin olive oil test sample. The study revealed that the direct transesterification of the sample without the prior removal of glycidol esters might lead to strong positive bias.
How global strategies emerge: an attention perspective
Authors: Bouquet Cyril , Birkinshaw Julian
Published: October 2011

Most prior research in the field of global strategy focuses on what choices executives make to build the competitive advantage of a firm, from setting up activities in different locations to coordinating the linkages between them. In this article, we shift the emphasis to how global strategies emerge in a firm by studying the processes through which top executive attention is channeled and structured. Building on the attention‐based view of the firm, we develop hypotheses linking aspects of the firm's operating environment and its internal organization to its international attention—the time and effort HQ executives invest in activities, communications, and discussions aimed at improving their understanding of the global marketplace. Using primary data collected from 134 firms across a large spectrum of industries, we test and find support for our arguments.
Physical attraction and the geography of knowledge sourcing in multinational enterprises
Authors: Cantwell John A. , Mudambi Ram
Published: October 2011

In this article, we develop the concept of the degree of physical attraction exerted by the dominant firms in a local industry on other actors that increases the ease of local knowledge search for ‘insiders’ with stronger connections to others. Conversely, the physical attraction of dominant firms on other actors raises the difficulty of local knowledge search for ‘outsiders’ with weaker connections to others. Our theory has important implications for knowledge spillovers. As local industry concentration rises, the likelihood of local knowledge spillovers to outsiders falls, even with a high local knowledge stock. Further, in contrast to the strategic deterrence thesis which posits that technology leaders are deterred from entering clusters for fear of knowledge outflows, our theory implies that with high industrial concentration, it is technology laggards that are deterred, since they do not have the wherewithal to establish the local connections needed to access knowledge inflows. Using a large patent database associated with the U.K.‐based subsidiaries of non‐U.K. MNEs, we find strong support for our theory.
Targeted expression of Escherichia coli purine nucleoside phosphorylase and Fludara® for prostate cancer therapy
Authors: Xie Xinhua , Guo Jiaoli , Kong Yanan , Xie Gene Xianquan , Li Laishen , Lv Ning , Xiao Xiangsheng , Tang Jun , Wang Xi , Liu Peng , Yang Mingtian , Xie Zeming , Wei Weidong , Xie Xiaoming
Published: October 2011

Background

Previous studies have shown that Herpes Simplex Virus thymidine kinase (HSV‐tk)/ganciclovir (GCV) comprised the most commonly used suicide gene therapy for prostate cancer, with modest results being obtained. However, novel suicide genes, such as Escherichia coli purine nucleoside phosphorylase (PNP), have been utilized to demonstrate more potent tumor killing and an enhanced bystander effect on local, non‐expressing cells compared to HSV‐tk.

Methods

PNP/fludarabine (Fludara®; fludarabine phosphate; Berlex Labs, Richmond, CA, USA) was deliveried by prostate‐specific, rat probasin‐based promoter, ARR2PB. After infection of various cell lines with ADV.ARR2PB‐PNP and administration of androgen analog, R1881, expression of PNP mRNA was detected; in vivo, the antitumor effect of the ARR2PB‐PNP/Fludara system was monitored and analyzed, as well as animal survival.

Results

After in vitro infection with ADV.ARR2PB‐PNP (multiplicity of infection = 10), LNCaP cells were more sensitive to a lower concentration Fludara (LD50, approximately 0.1 µg/ml) in the presence of R1881. Furthermore, robust bystander effects after R1881/Fludara treatment were observed in LNCaP cells after infection with bicistronic vector ADV.ARR2PB/PNP‐IRES‐EGFP in contrast to a much weaker effect in cells treated with ADV.CMV‐HSV‐tk/GCV. In vivo, tumor size in the ADV.ARR2PB‐PNP/Fludara treatment group was dramatically smaller than in the control groups, and the mice treated with our system had a significantly prolonged survival, with three of eight mice surviving up to the 160‐day termination point, as well as no systemic toxicity.

Conclusions

The ARR2PB‐PNP/Fludara system induced massive tumor cell death and a prolonged life span without systemic cytotoxicity; therefore, it might be a more attractive strategy for suicide gene therapy of prostate cancer. Copyright © 2011 John Wiley & Sons, Ltd.
Racemic synthesis of 2′‐substituted nicotine analogs
Authors: Rouchaud Anne , Kem William R.
Published: October 2011

The chemical and pharmacological properties of 2′‐substituted nicotines are poorly understood relative to other substituted nicotines. We developed a practical synthesis of the key intermediate (±)‐2′‐cyanonicotine using the Polonovski reaction. Alkylation of (±)‐2′‐cyanonicotine with Grignard reagents led to several 2′‐alkylnicotines; (±)‐2′‐aminomethylnicotine, (±)‐2′‐hydroxymethylnicotine, and (±)‐2′‐carbamoylnicotine were also synthesized. J. Heterocyclic Chem., (2012).
Eag1, Eag2, and SK3 potassium channel expression in the rat hippocampus after global transient brain ischemia
Authors: de Oliveira R.M. Weffort , Martin S. , de Oliveira C. Lino , Milani H. , Schiavon A.P. , Joca S. , Pardo L.A. , Stühmer W. , Del Bel E.A.
Published: October 2011

Transient global brain ischemia causes delayed neuronal death in the hippocampus that has been associated with impairments in hippocampus‐dependent brain function, such as mood, learning, and memory. We investigated the expression of voltage‐dependent Kcnh1 and Kcnh5, ether à go‐go‐related Eag1 and Eag2 (KV10.1 and KV10.2), and small‐conductance calcium‐activated SK3 (KCa2.3, Kcnn3) K+ channels in the hippocampus in rats after transient global brain ischemia. We tested whether the expression of these channels is associated with behavioral changes by evaluating the animals in the elevated plus maze and step‐down inhibitory avoidance task. Seven or tweny‐eight days after transient global brain ischemia, one group of rats had the hippocampus bilaterally dissected, and mRNA levels were determined. Seven days after transient global brain ischemia, the rats exhibited a decrease in anxiety‐like behavior and memory impairments. An increase in anxiety levels was detected 28 days after ischemia. Eag2 mRNA downregulation was observed in the hippocampus 7 days after transient global brain ischemia, whereas Eag1 and SK3 mRNA expression remained unaltered. This is the first experimental evidence that transient global brain ischemia temporarily alters Eag2. The number of intact‐appearing pyramidal neurons was substantially decreased in CA1 and statistically measurable in CA2, CA3, and CA4 hippocampal subfields compared with sham control animals 7 or 28 days after ischemia. mRNA expression in the rat hippocampus. The present results provide further information for the characterization of the physiological role of Eag2 channels in the central nervous system. © 2011 Wiley Periodicals, Inc.
A critical literature review on the processing of table olives
Authors: Frankel Edwin
Published: October 2011

About 20% of the fruits of olive trees are used for producing table olives, but the literature on the lipid composition of extracted table olives is limited and controversial. Although, the composition of olive oils extracted from various sources has been extensively reported, excessive efforts have been devoted on the use of undefined chemometric methods requiring sophisticated statistical techniques. More reliable and sensitive chemical methods are required to analyze oils from different olive preparations, including widely ranging polyunsaturated fatty acids that affect significantly the oxidative stability of the extracted oils.
The synthesis, properties, and applications of ascorbyl esters
Authors: Karmee Sanjib Kumar
Published: October 2011

Ascorbic acid is a naturally occurring antioxidant. Nevertheless, its primary applications as an antioxidant in the life science, food and pharmaceutical industries are limited because of its hydrophilic nature. Alternatively, ascorbyl acid esters are potential surfactants and antioxidants. Chemical methods for the synthesis of ascorbyl esters lead to the formation of side products and simultaneous decomposition of ascorbic acid due to harsh reaction conditions. In contrast, lipases are used as regioselective and mild catalysts for the synthesis of ascorbyl esters. So far, various acyl donors namely, fatty acids, fatty acid alkyl esters, fatty acid vinyl esters and triacylglycerols have been explored for the synthesis of ascorbyl fatty esters. Other compounds such as L‐methyl lactate, bixin, phenyl butyric acid are also used as acyl donors. This article is focused on the recent developments of lipase‐catalyzed synthesis of ascorbyl esters, their antioxidant properties and applications.
Branched and Network Polysilanes as Cleavable Macrophotoinitiators
Authors: Tehfe Mohamad‐Ali , Lalevée Jacques , Shankar Ravi , Sahoo Usharani , Morlet‐Savary Fabrice , Graff Bernadette , Fouassier Jean‐Pierre
Published: October 2011

The branched polysilane [(PhMeSi)0.8‐co‐(Et3Si(CH2)2Si)0.2]n (PS‐1) as well as the network polysilane [Et3Si(CH2)3Si]n (PS‐2) have been investigated as new polymerization photoinitiating structures. The behavior of PS‐1 was compared with that of [(PhMeSi)]n to demonstrate the enhancement of the photoinitiation for the branched system. As a result of the Si–Si bond cleavage under light and the formation of reactive silyl radicals or silyl cations, these compounds act as efficient photoinitiators (PIs) for free radical photopolymerization (FRP) and free radical promoted cationic polymerization (FRPCP). The polymerization initiating ability of PS‐1 is higher than that of PS‐2 under air. The initiating ability for the ring‐opening polymerization of epoxides is excellent for PS‐1. These polymeric PIs overcome the classical oxygen inhibition in FRP or FRPCP.
Self‐Rolled Polymer Tubes: Novel Tools for Microfluidics, Microbiology, and Drug‐Delivery Systems
Authors: Luchnikov Valeriy , lonov Leonid , Stamm Manfred
Published: October 2011

Recent work on the fabrication of tubular microstructures via self‐rolling of thin, bilayer polymer films is reviewed. A bending moment in the films arises due to the swelling of one component of the bilayer in a selective solvent. The inner diameters of the tubes vary from hundreds of nanometers to dozens of micrometers. The position of the tubes on the substrate and their length can be preset by photolithographic patterning of the bilayer. Prior to rolling, the bilayers can be exposed to different methods of surface functionalization, providing opportunities for engineering the microtube inner surfaces for use in microfluidic circuits and “microbiological” applications. The self‐rolling approach is promising for the development of novel drug‐ and cell‐delivery systems, as well as for tissue engineering.
Self‐Assembly of Rod–Coil Polyethylenimine–Poly(ethylene glycol)–α‐Cyclodextrin Inclusion Complexes into Hollow Spheres and Rod‐Like Particles
Authors: Cheng Cong , Han Xiao‐Juan , Dong Zhen‐Qiang , Liu Yan , Li Bang‐Jing , Zhang Sheng
Published: October 2011

This paper describes the self‐assembly of rod–coil inclusion complexes, polyethylenimine–poly(ethylene glycol)–α‐cyclodextrin (PEI–PEG–α‐CD). It is demonstrated that α‐CDs should exclusively thread on the PEG block in PEI–PEG copolymers and the resulting complexes have both rigid block (PEG–α‐CD) and coil block (protonated PEI). By varying the rigid block fraction, aggregates with hollow spheres or rod‐like particles could be formed simply by self‐assembly in aqueous solution.
Optimal Two‐part Pricing under Cost Uncertainty
Authors: Wong Kit Pong
Published: October 2011

This paper examines the optimal two‐part pricing under cost uncertainty. We consider a risk‐averse monopolistic firm that is subject to a cost shock to its constant marginal cost of production. The firm uses two‐part pricing to sell its output to a continuum of heterogeneous consumers. We show that the global and marginal effects of risk aversion on the firm's optimal two‐part pricing are to raise the unit price and lower the fixed payment. We further show that an increase in the fixed cost of production induces the firm to raise (lower) the unit price and lower (raise) the fixed payment under decreasing (increasing) absolute risk aversion. The firm's optimal two‐part pricing is unaffected by changes in the fixed cost under constant absolute risk aversion. Finally, we show that a mean‐preserving spread increase in cost uncertainty induces the firm to raise the unit price and lower the fixed payment under either decreasing or constant absolute risk aversion. Copyright © 2011 John Wiley & Sons, Ltd.
3D magnetic resonance microscopy of the ex vivo retina
Authors: De La Garza Bryan H. , Muir Eric R. , Shih Yen‐Yu I. , Duong Timothy Q.
Published: October 2011

3D‐MR microscopy at 11.7T and 20 × 20 × 57 μm resolution was performed on formalin‐fixed rat eyes with: (I) no contrast agent and (II) Gadodiamide (Omniscan®) added to the fixative. Group I data showed generally poor contrast among layers. Group II data showed markedly better lamina‐specific contrast with the nerve fiber + ganglion cell layer and inner nuclear layer being hypointense, and the inner plexiform, outer plexiform, outer nuclear layer, and the segments being hyperintense. The signal‐to‐noise ratio in group II was higher than group I, consistent with Gadodiamide acting as a T1‐contrast agent. All major retinal layers were assigned and their thicknesses quantified with corroboration by histology. MR microscopy allows nondestructive examination of valuable specimens and could have applications in disease and in vivo. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Amide proton transfer imaging with improved robustness to magnetic field inhomogeneity and magnetization transfer asymmetry using saturation with frequency alternating RF irradiation
Authors: Scheidegger Rachel , Vinogradov Elena , Alsop David C.
Published: October 2011

Amide proton transfer (APT) imaging results in a representative human volunteer. a: B0 map calculated from the low SNR z‐spectrum images by the B0 correction algorithm. b: MTRasym map and c: MTRSAFARI map calculated from the high SNR APT images without B0 correction. The uncorrected MTRasym map shows large spatial intensity variation over the brain, which corresponds to the water frequency shift map. The uncorrected MTRSAFARI map shows a remarkable improvement in homogeneity over the brain. From the article by Scheidegger et al (pp 1275‐1285).
Detection of prostaglandin E2‐induced dendritic cell migration into the lymph nodes of mice using a 1.5 T clinical MR scanner
Authors: Joo Hyun Jung , Kim Hoe Suk , Choi Yoon Seok , Kim Hyeonjin , Kim Seung Ja , Moon Woo Kyung
Published: October 2011

The control of dendritic cell (DC) migration into lymph nodes (LNs) is important for the development of more effective DC‐based immunotherapies. This study was undertaken to evaluate, dynamically and noninvasively, prostaglandin E2 (PGE2)‐enhanced migration of DCs using a 1.5 T clinical MR scanner. DC2.4 cells were labeled with superparamagnetic iron oxide (SPIO), a clinically approved MRI contrast agent. DCs were stimulated with tumor necrosis factor‐α and interferon‐γ in the presence or absence of PGE2. Before and after subcutaneous injection of labeled DCs into the hind leg footpads of mice, MRI detailing the extent of DC migration into popliteal LNs was performed using a 1.5 T clinical MR scanner. SPIO labeling did not influence the viability, endocytic activity, migratory ability and/or co‐stimulatory molecule expression of DCs. PGE2 enhanced significantly chemokine receptor‐7 expression and the migration of DCs (p < 0.05). After subcutaneous injection of DCs, there were decreases in MR signal intensity in popliteal LNs at 24 h post‐injection; in PGE2‐treated cells, the MR signal intensity was significantly lower (decrease of 86.6 ± 2.5%) than in PGE2‐untreated cells (decrease of 70.0 ± 4.2%) (p < 0.05). Histological analyses with the conventionally used Prussian blue stain demonstrated that the PGE2‐treated DCs migrated more deeply into the center of LNs. PGE2‐enhanced migration of SPIO‐labeled DCs into LNs can be detected using a 1.5 T clinical MR scanner. Our results suggest that in vivo MRI of DC migration is a useful imaging method to predict DC therapy with a high rate of efficacy and to improve DC‐based immunotherapy, thereby reducing costs compared with current treatments in clinical trials. Copyright © 2011 John Wiley & Sons, Ltd.
Mixed, componentwise condition numbers and small sample statistical condition estimation of Sylvester equations
Authors: Diao Huaian , Xiang Hua , Wei Yimin
Published: October 2011

We present a componentwise perturbation analysis for the continuous‐time Sylvester equations. Componentwise, mixed condition numbers and new perturbation bounds are derived for the matrix equations. The small sample statistical method can also be applied for the condition estimation. These condition numbers and perturbation bounds are tested on numerical examples and compared with the normwise condition number. The numerical examples illustrate that the mixed condition number gives sharper bounds than the normwise one. Copyright © 2011 John Wiley & Sons, Ltd.
Inexact uniformization and GMRES methods for large Markov chains
Authors: Sidje Roger B.
Published: October 2011

Inexact algorithms allow certain operations (typically matrix–vector products or certain function evaluations) to be performed inexactly, either out of necessity or deliberately, in view of trading accuracy for speed. We review recent findings that show the impact of the inexact approach in the uniformization and generalized minimal residual (GMRES) methods when computing the transient, stationary, and cumulative solutions of realistic Markov chain problems of large size arising from computer systems and biochemical reactions. Copyright © 2011 John Wiley & Sons, Ltd.
Efficient parallel solution to large‐size sparse eigenproblems with block FSAI preconditioning
Authors: Ferronato Massimiliano , Janna Carlo , Pini Giorgio
Published: October 2011

The choice of the preconditioner is a key factor to accelerate the convergence of eigensolvers for large‐size sparse eigenproblems. Although incomplete factorizations with partial fill‐in prove generally effective in sequential computations, the efficient preconditioning of parallel eigensolvers is still an open issue. The present paper describes the use of block factorized sparse approximate inverse (BFSAI) preconditioning for the parallel solution of large‐size symmetric positive definite eigenproblems with both a simultaneous Rayleigh quotient minimization and the Jacobi–Davidson algorithm. BFSAI coupled with a block diagonal incomplete decomposition proves a robust and efficient parallel preconditioner in a number of test cases arising from the finite element discretization of 3D fluid‐dynamical and mechanical engineering applications, outperforming FSAI even by a factor of 8 and exhibiting a satisfactory scalability. Copyright © 2011 John Wiley & Sons, Ltd.
A new approximation of the Schur complement in preconditioners for PDE‐constrained optimization
Authors: Pearson John W. , Wathen Andrew J.
Published: October 2011

Saddle point systems arise widely in optimization problems with constraints. The utility of Schur complement approximation is now broadly appreciated in the context of solving such saddle point systems by iteration. In this short manuscript, we present a new Schur complement approximation for PDE‐constrained optimization, an important class of these problems. Block diagonal and block triangular preconditioners have previously been designed to be used to solve such problems along with MINRES and non‐standard Conjugate Gradients, respectively; with appropriate approximation blocks, these can be optimal in the sense that the time required for solution scales linearly with the problem size, however small the mesh size we use. In this paper, we extend this work to designing such preconditioners for which this optimality property holds independently of both the mesh size and the Tikhonov regularization parameterβthat is used. This also leads to an effective symmetric indefinite preconditioner that exhibits mesh andβindependence. We motivate the choice of these preconditioners based on observations about approximating the Schur complement obtained from the matrix system, derive eigenvalue bounds that verify the effectiveness of the approximation and present numerical results that show that these new preconditioners work well in practice. Copyright © 2011 John Wiley & Sons, Ltd.
Physiology and pathology of iterative aggregation–disaggregation methods
Authors: Pultarová I. , Marek I.
Published: October 2011

We found characteristics that can help us predict the convergence or divergence of iterative aggregation–disaggregation methods. We provided two results for spectral radii of asymptotic error propagation matrices: (i) the spectral radius is bounded by unity for symmetric Markov chains and (ii) the spectral radius can be arbitrarily large for a certain class of sparse Markov chains. Surprisingly, permuting states of cyclic Markov chains by algorithms usually used for reducing bandwidth of matrices leads to the latter case. We proposed a sorting method that prevents divergence for this class of Markov chains.Copyright © 2011 John Wiley & Sons, Ltd.
Towards a theoretical framework for the governing of stakeholder relationships: a perspective from South Africa
Authors: de Beer Estelle , Rensburg Ronél
Published: October 2011

Including stakeholder approaches into mainstream strategy has been a topic of recent research in the disciplines of strategic management and strategic communication management. The King III Report on Corporate Governance for South Africa (September 2009) illustrates the pragmatic approach to this integration with its chapter on ‘Governing Stakeholder Relationships’. This inclusive approach to governance creates awareness among business, government and civil society, of the role that stakeholder relationship management, and therefore strategic communication management, can play in the development, implementation and monitoring of corporate strategies in a sustainable manner. A theoretical framework for an integrated approach—as developed in this article—will guide responsible strategic communication management with specific reference to the governing of stakeholder relationships. It will demonstrate that communication management principles, such as stakeholder relationship management, can assist an organisation in achieving its objectives—even to a point of becoming objectives in themselves. Copyright © 2011 John Wiley & Sons, Ltd.