bluuebunny/crossref_metadata_2025 huggingface dataset:
Beneficial Effects of Ischemic Preconditioning on Pancreas Cold Preservation
Authors: Hogan Anthony R. , Doni Marco , Molano R. Damaris , Ribeiro Melina M. , Szeto Angela , Cobianchi Lorenzo , Zahr-Akrawi Elsie , Molina Judith , Fornoni Alessia , Mendez Armando J. , Ricordi Camillo , Pastori Ricardo L. , Pileggi Antonello
Published: February 2012

Ischemic preconditioning (IPC) confers tissue resistance to subsequent ischemia in several organs. The protective effects are obtained by applying short periods of warm ischemia followed by reperfusion prior to extended ischemic insults to the organs. In the present study, we evaluated whether IPC can reduce pancreatic tissue injury following cold ischemic preservation. Rat pancreata were exposed to IPC (10 min of warm ischemia followed by 10 min of reperfusion) prior to ~18 h of cold preservation before assessment of organ injury or islet isolation. Pancreas IPC improved islet yields (964 ± 336 vs. 711 ± 204 IEQ/pancreas; p = 0.004) and lowered islet loss after culture (33 ± 10% vs. 51 ± 14%; p = 0.0005). Islet potency in vivo was well preserved with diabetes reversal and improved glucose clearance. Pancreas IPC reduced levels of NADPH-dependent oxidase, a source of reactive oxygen species, in pancreas homogenates versus controls (78.4 ± 45.9 vs. 216.2 ± 53.8 RLU/μg; p = 0.002). Microarray genomic analysis of pancreata revealed upregulation of 81 genes and downregulation of 454 genes (greater than twofold change) when comparing IPC-treated glands to controls, respectively, and showing a decrease in markers of apoptosis and oxidative stress. Collectively, our study demonstrates beneficial effects of IPC of the pancreas prior to cold organ preservation and provides evidence of the key role of IPC-mediated modulation of oxidative stress pathways. The use of IPC of the pancreas may contribute to increasing the quality of donor pancreas for transplantation and to improving organ utilization.
Pretreatment of Endothelial Progenitor Cells with Osteopontin Enhances Cell Therapy for Peripheral Vascular Disease
Authors: Vaughan E. E. , Liew A. , Mashayekhi K. , Dockery P. , McDermott J. , Kealy B. , Flynn A. , Duffy A. , Coleman C. , O'regan A. , Barry F. P. , O'brien T.
Published: February 2012

Tissue necrosis resulting from critical limb ischemia (CLI) leads to amputation in a significant number of patients. Autologous cell therapy using angiogenic cells such as endothelial progenitor cells (EPCs) holds promise as a treatment for CLI but a limitation of this treatment is that the underlying disease etiology that resulted in CLI may also contribute to dysfunction of the therapeutic EPCs. This study aimed to elucidate the mechanism of EPC dysfunction using diabetes mellitus as a model and to determine whether correction of this defect in dysfunctional EPCs ex vivo would improve the outcome after cell transplantation in the murine hind limb ischemia model. EPC dysfunction was confirmed in a homogenous population of patients with type 1 diabetes mellitus and a microarray study was preformed to identify dysregulated genes. Notably, the secreted proangiogenic protein osteopontin (OPN) was significantly downregulated in diabetic EPCs. Furthermore, OPN-deficient mice showed impaired recovery following hind limb ischemia, suggesting a critical role for OPN in postnatal neovascularization. EPCs isolated from OPN KO mice showed decreased ability to adhere to endothelial cells as well as impaired angiogenic potential. However, this dysfunction was reversed upon exposure to recombinant OPN, suggesting that OPN may act in an autocrine manner on EPCs. Indeed, exposure of OPN knockout (KO) EPCs to OPN was sufficient to induce the secretion of angiogenic proteins (IL-6, TGF-α, and FGF-α). We also demonstrated that vascular regeneration following hind limb ischemia in OPN KO mice was significantly improved upon injection of EPCs preexposed to OPN. We concluded that OPN acts in an autocrine manner on EPCs to induce the secretion of angiogenic proteins, thereby playing a critical role in EPC-mediated neovascularization. Modification of cells by exposure to OPN may improve the efficacy of autologous EPC transplantation via the enhanced secretion of angiogenic proteins.
Impact of Tissue Volume and Purification on Clinical Autologous Islet Transplantation for the Treatment of Chronic Pancreatitis
Authors: Matsumoto Shinichi , Takita Morihito , Shimoda Masayuki , Sugimoto Koji , Itoh Takeshi , Chujo Daisuke , Sorelle Jeffery A. , Tamura Yoshiko , Rahman Ana M. , Onaca Nicholas , Naziruddin Bashoo , Levy Marlon F.
Published: February 2012

Autologous islet transplantation after total pancreatectomy is an excellent treatment for painful chronic pancreatitis. Traditionally, islets have been isolated without purification; however, purification is applied when the tissue volume is large. Nevertheless, the impact of tissue volume and islet purification on clinical outcomes of autologous islet transplantation has not been well examined. We analyzed 27 cases of autologous islet transplantation performed from October 2006 to January 2011. After examining the relationship between tissue volume and portal pressure at various time points, we compared islet characteristics and clinical outcomes between cases with complications (complication group) and without (noncomplication group), as well as cases with purification (purification group) and without (nonpurification group). Tissue volume significantly correlated with maximum ( R = 0.61), final ( R = 0.53), and delta (i.e., difference between base and maximum; R = 0.71) portal pressure. The complication group had a significantly higher body mass index, tissue volume, islet yield, and portal pressure (maximum, final, delta), suggesting that complications were associated with high tissue volume and high portal pressure. Only one of four patients (25%) in the complication group became insulin free, whereas 11 of 23 patients (49%) in the noncomplication group became insulin free with smaller islet yields. The purification group had a higher islet yield and insulin independence rate but had similar final tissue volume, portal pressure, and complication rates compared with the nonpurification group. In conclusion, high tissue volume was associated with high portal pressure and complications in autologous islet transplantation. Islet purification effectively reduced tissue volume and had no negative impact on islet characteristics. Therefore, islet purification can reduce the risk of complications and may improve clinical outcome for autologous islet transplantation when tissue volume is large.
Adipose Tissue-Derived Stem Cell Treatment Prevents Renal Disease Progression
Authors: Donizetti-Oliveira Cassiano , Semedo Patricia , Burgos-Silva Marina , Cenedeze Marco Antonio , Malheiros Denise Maria Avancini Costa , Reis Marlene A. , Pacheco-Silva Alvaro , Câmara Niels Olsen Saraiva
Published: February 2012

Adipose tissue-derived stem cells (ASCs) are an attractive source of stem cells with regenerative properties that are similar to those of bone marrow stem cells. Here, we analyze the role of ASCs in reducing the progression of kidney fibrosis. Progressive renal fibrosis was achieved by unilateral clamping of the renal pedicle in mice for 1 h; after that, the kidney was reperfused immediately. Four hours after the surgery, 2 × 105ASCs were intraperitoneally administered, and mice were followed for 24 h posttreatment and then at some other time interval for the next 6 weeks. Also, animals were treated with 2 × 105ASCs at 6 weeks after reperfusion and sacrificed 4 weeks later to study their effect when interstitial fibrosis is already present. At 24 h after reperfusion, ASC-treated animals showed reduced renal dysfunction and enhanced regenerative tubular processes. Renal mRNA expression of IL-6 and TNF was decreased in ASC-treated animals, whereas IL-4, IL-10, and HO-1 expression increased despite a lack of ASCs in the kidneys as determined by SRY analysis. As expected, untreated kidneys shrank at 6 weeks, whereas the kidneys of ASC-treated animals remained normal in size, showed less collagen deposition, and decreased staining for FSP-1, type I collagen, and Hypoxyprobe. The renal protection seen in ASC-treated animals was followed by reduced serum levels of TNF-α, KC, RANTES, and IL-1α. Surprisingly, treatment with ASCs at 6 weeks, when animals already showed installed fibrosis, demonstrated amelioration of functional parameters, with less tissue fibrosis observed and reduced mRNA expression of type I collagen and vimentin. ASC therapy can improve functional parameters and reduce progression of renal fibrosis at early and later times after injury, mostly due to early modulation of the inflammatory response and to less hypoxia, thereby reducing the epithelial–mesenchymal transition.
A Novel NKR-P1Bbright NK Cell Subset Expresses an Activated CD25+CX3CR1+CD62L−CD11b−CD27− Phenotype and Is Prevalent in Blood, Liver, and Gut-Associated Lymphoid Organs of Rats
Authors: Inngjerdingen Marit , Kveberg Lise , Vaage John T.
Published: February 2012

The inhibitory NKR-P1B receptor identifies a subset of rat splenic NK cells that is low in Ly49 receptors but enriched for CD94/NKG2 receptors. We report in this study a novel NKR-P1Bbright NK subpopulation that is prevalent in peripheral blood, liver, and gut-associated lymphoid organs and scarce in the spleen, peripheral lymph nodes, bone marrow, and lungs. This NKR-P1Bbright NK subset displays an activated phenotype, expressing CD25, CD93, CX3CR1 and near absence of CD62-L, CD11b, and CD27. Functionally, NKR-P1Bbright NK cells are highly responsive in terms of IFN-γ production and exert potent cytolytic activity. They show little spontaneous proliferation, are reduced in numbers upon in vivo activation with polyinosinic:polycytidylic acid, and have poor survival in ex vivo cytokine cultures. Our findings suggest that NKR-P1Bbright NK cells are fully differentiated effector cells that rapidly die upon further activation. The identification of this novel rat NK cell subset may facilitate future translational research of the role of distinct NK cell subsets under normal physiological conditions and during ongoing immune responses.
Tyrosine Phosphorylation-Independent Regulation of Lipopolysaccharide-Mediated Response by the Transmembrane Adaptor Protein LAB
Authors: Zhu Minghua , Fuller Deirdre M. , Ou-Yang Chih-wen , Sullivan Sarah A. , Zhang Weiguo
Published: February 2012

Linker for activation of B cells (LAB)/non-T cell activation linker is a transmembrane adaptor protein that functions in immunoreceptor-mediated signaling. Published studies have shown that LAB has both positive and negative roles in regulating TCR and high-affinity Fc receptor-mediated signaling and cellular function. In this study, we showed that LAB was also expressed in dendritic cells and that LAB deficiency affected LPS-mediated signaling and cytokine production. LPS-mediated MAPK activation was enhanced in LAB−/− bone marrow-derived dendritic cells. These bone marrow-derived dendritic cells also produced more TNF-α, IL-6, and IL-10 than wild-type cells. Moreover, LAB−/− mice were hyperresponsive to LPS-induced septic shock. These data indicated that LAB has a negative role in LPS-mediated responses. By using LAB knockin mice, which harbor mutations at five membrane-distal tyrosines, we further showed that, in contrast to its role in immunoreceptor-mediated signaling, LAB function in LPS-mediated signaling pathway did not depend on its tyrosine phosphorylation. Our study suggested a novel mechanism by which LAB functions in the regulation of innate immunity.
Removal of Syndecan-1 Promotes TRAIL-Induced Apoptosis in Myeloma Cells
Authors: Wu Yung-Hsuan , Yang Chen-Ying , Chien Wen-Li , Lin Kuo-I , Lai Ming-Zong
Published: February 2012

Syndecan is the major transmembrane proteoglycan in cells. Of the four syndecans, syndecan-1 is the dominant form expressed in multiple myeloma and is an indicator of poor prognosis. In the current study, we observed that early TRAIL-induced apoptotic processes were accompanied by cleavage of syndecan-1 intracellular region, and explored the possibility whether removal of syndecan-1 promotes apoptotic processes. We found that syndecan-1 knockdown by specific small interfering RNA in multiple myeloma enhanced TRAIL-induced apoptosis, even though the expression of TRAIL receptors and several apoptosis-associated molecules was unaffected. The enhanced TRAIL-mediated apoptosis in syndecan-1–deficient cells was not due to a decrease in surface heparan sulfate or a reduction in TRAIL receptor endocytosis. The increase in TRAIL-induced cell death was accompanied by an elevated caspase-8 activation and an enhanced formation of death-inducing signaling complexes, which could be attributed to an increased expression of TRAIL receptor O-glycosylation enzyme in syndecan-1–deficient cells. We also found that in H9 lymphoma and Jurkat cells, knockdown of the predominant syndecan member also led to an increase in Fas ligand-induced apoptosis. Our results demonstrate that syndecan plays a negative role in death receptor-mediated cell death, suggesting potential application of syndecan downregulation in the treatment of myeloma in combination with TRAIL.
Recognition and Prevention of Tumor Metastasis by the NK Receptor NKp46/NCR1
Authors: Glasner Ariella , Ghadially Hormas , Gur Chamutal , Stanietsky Noa , Tsukerman Pinchas , Enk Jonatan , Mandelboim Ofer
Published: February 2012

NK cells employ a variety of activating receptors to kill virally infected and tumor cells. Prominent among these receptors are the natural cytotoxicity receptors (NCRs) (NKp30, NKp44, and NKp46), of which only NKp46 has a mouse ortholog (NCR1). The tumor ligand(s) of NKp46/NCR1 is still unknown, but it was shown that the human NKp46 and the mouse NCR1 are involved in tumor eradication both in vitro and in vivo. Whether any of the NK activating receptors is involved in the prevention of tumor metastasis is unknown. To address this question, we studied the activity of the NK cell receptor NKp46/NCR1 in two spontaneous metastasis models, the B16F10.9 melanoma (B16) and the Lewis lung carcinoma (D122) in the NCR1 knockout mouse that was generated by our group, in various in vitro and in vivo assays. We demonstrated that all B16 and D122 tumors, including those generated in vivo, express an unknown ligand(s) for NKp46/NCR1. We have characterized the properties of the NKp46/NCR1 ligand(s) and demonstrated that NKp46/NCR1 is directly involved in the killing of B16 and D122 cells. Importantly, we showed in vivo that NKp46/NCR1 plays an important role in controlling B16 and D122 metastasis. Thus, to our knowledge, in this study we provide the first evidence for the direct involvement of a specific NK killer receptor in preventing tumor metastasis.
Chronic Shift-Lag Alters the Circadian Clock of NK Cells and Promotes Lung Cancer Growth in Rats
Authors: Logan Ryan W. , Zhang Changqing , Murugan Sengottuvelan , O’Connell Stephanie , Levitt Dale , Rosenwasser Alan M. , Sarkar Dipak K.
Published: February 2012

Prolonged subjection to unstable work or lighting schedules, particularly in rotating shift-workers, is associated with an increased risk of immune-related diseases, including several cancers. Consequences of chronic circadian disruption may also extend to the innate immune system to promote cancer growth, as NK cell function is modulated by circadian mechanisms and plays a key role in lysis of tumor cells. To determine if NK cell function is disrupted by a model of human shift-work and jet-lag, Fischer (344) rats were exposed to either a standard 12:12 light-dark cycle or a chronic shift-lag paradigm consisting of 10 repeated 6-h photic advances occurring every 2 d, followed by 5–7 d of constant darkness. This model resulted in considerable circadian disruption, as assessed by circadian running-wheel activity. NK cells were enriched from control and shifted animals, and gene, protein, and cytolytic activity assays were performed. Chronic shift-lag altered the circadian expression of clock genes, Per2 and Bmal1, and cytolytic factors, perforin and granzyme B, as well as the cytokine, IFN-γ. These alterations were correlated with suppressed circadian expression of NK cytolytic activity. Further, chronic shift-lag attenuated NK cell cytolytic activity under stimulated in vivo conditions, and promoted lung tumor growth following i.v. injection of MADB106 tumor cells. Together, these findings suggest chronic circadian disruption promotes tumor growth by altering the circadian rhythms of NK cell function.
An arithmetic Hilbert–Samuel theorem for pointed stable curves
Authors: Freixas i Montplet Gerard
Published: February 2012

Let

(\mathcal{O},∑,F_∞)

be an arithmetic ring of Krull dimension at most 1,

\mathcal S_ = \mathrm{Spec} \mathcal O

and

(\mathcal X → \mathcal S; σ_1, ..., σ_n)

a pointed stable curve. Write

\mathcal U =\mathcal Χ \backslash \bigcup_j σ_j(\mathcal S)

. For every integer

k\geq 0

, the invertible sheaf

ω^{k+1}_{Χ/{\mathcal S}}(kσ_1 + ... + kσ_n)

inherits a singular hermitian structure from the hyperbolic metric on the Riemann surface

\mathcal U_∞

. In this article we define a Quillen type metric

‖ ∙ ‖_Q

on the determinant line

λ_{k+1} = λ(ω^{k+1}_{Χ/{\mathcal S}}(kσ_1 + ... + kσ_n))

and compute the arithmetic degree of

(λ_{k+1}, ‖ ∙ ‖_Q)

by means of an analogue of the Riemann–Roch theorem in Arakelov geometry. As a byproduct, we obtain an arithmetic Hilbert–Samuel formula: the arithmetic degree of

(λ_{k+1}, ‖ ∙ ‖_{L^2})

admits an asymptotic expansion in

k

, whose leading coefficient is given by the arithmetic self-intersection of

(ω_{Χ/{\mathcal S}}(σ_1 + ... + σ_n), ‖ ∙ ‖_{\mathrm{hyp}})

. Here

‖ ∙ ‖_{L^2}

and

‖ ∙ ‖_{\mathrm{hyp}}

denote the

L^2

metric and the dual of the hyperbolic metric, respectively. Examples of application are given for pointed stable curves of genus 0.
Highest weight categories arising from Khovanov's diagram algebra IV: the general linear supergroup
Authors: Brundan Jonathan , Stroppel Catharina
Published: February 2012

We prove that blocks of the general linear supergroup are Morita equivalent to a limiting version of Khovanov's diagram algebra. We deduce that blocks of the general linear supergroup are Koszul.
Real zeros of holomorphic Hecke cusp forms
Authors: Ghosh Amit , Sarnak Peter
Published: February 2012

This note is concerned with the zeros of holomorphic Hecke cusp forms of large weight on the modular surface. The zeros of such forms are symmetric about three geodesic segments and we call those zeros that lie on these segments, real. Our main results give estimates for the number of real zeros as the weight goes to infinity.
Idempotent semigroups and tropical algebraic sets
Authors: Izhakian Zur , Shustin Eugenii
Published: February 2012

The tropical semifield, i.e., the real numbers enhanced by the operations of addition and maximum, serves as a base of tropical mathematics. Addition is an abelian group operation, whereas the maximum defines an idempotent semigroup structure. We address the question of the geometry of idempotent semigroups, in particular, tropical algebraic sets carrying the structure of a commutative idempotent semigroup. We show that commutative idempotent semigroups are contractible, that systems of tropical polynomials, formed from univariate monomials, define subsemigroups with respect to coordinate-wise tropical addition (maximum); and, finally, we prove that the subsemigroups in the Euclidean space which are either tropical hypersurfaces, or tropical curves in the plane or in the three-space have the above polynomial description.
Poisson geometry of directed networks in an annulus
Authors: Gekhtman Michael , Shapiro Michael , Vainshtein Alek
Published: February 2012

As a generalization of Postnikov's construction [P], we define a map from the space of edge weights of a directed network in an annulus into a space of loops in the Grassmannian. We then show that universal Poisson brackets introduced for the space of edge weights in [GSV3] induce a family of Poisson structures on rational matrix-valued functions and on the space of loops in the Grassmannian. In the former case, this family includes, for a particular kind of networks, the Poisson bracket associated with the trigonometric R-matrix.
Survey of socio-demographic and motivational donated breast milk
Authors: Weschenfelder Simone , Martins Ruth Geralda Germana , Peixoto Henry Maia
Published: February 2012

Objetivo: Levantar informações sócio-demográficas e motivacionais das Doadoras em um Banco de Leite Humano do Distrito Federal. Metodologia: estudo quantitativo, descritivo, com amostra de conveniência, que realizou entrevistas domiciliares, utilizando-se de um questionário estruturado, realizadas entre janeiro a março de 2011. Participaram 30 doadoras cadastradas em um banco de leite da rede pública, conforme aprovação do Comitê de Ética em Pesquisa Envolvendo Seres Humanos, com o parecer 424/2010. Resultados: observou-se, entre as doadoras entrevistadas, maior frequência de primigestas, adultas, casadas, boa escolaridade (ensino superior completo) e renda familiar mensal variada. E entre os principais motivos que fizeram as lactantes se tornarem doadoras e se manterem doando leite humano estão: porque me sinto bem em ajudar crianças que necessitam de leite humano e porque gostei da experiência de doar leite humano. Conclusão: as doadoras de leite humano são primigestas, adultas, casadas, com boa escolaridade e renda familiar mensal variada. Os motivos que as levaram a se tornarem doadoras estão relacionados à necessidade das mulheres em ajudar os bebês que necessitam de leite humano para sobreviver, os achados dessa pesquisa não corroboram o encontrado em pesquisas anteriores, onde as lactantes doavam seu leite para aliviar a dor causada pelo ingurgitamento mamário. Descritores: bancos de leite; aleitamento materno; amamentação.
Perception of nursing mothers on the support of primary care nurse to exclusive breastfeeding
Authors: Brito Andiara Araújo Cunegundes , Cavalcante Rosangela Diniz , Farias Taiza Rôse De Oliveira
Published: February 2012

Objetivo: analisar a assistência do enfermeiro da Estratégia Saúde da Família no âmbito do apoio ao aleitamento materno exclusivo, baseado na percepção de nutrizes. Métodos: pesquisa de caráter descritivo e exploratório, com abordagem qualitativa. Os sujeitos da pesquisa serão nutrizes que amamentam exclusivamente até o quarto mês e que realizaram o pré-natal com os enfermeiros da Estratégia Saúde da Família de Caicó. As entrevistas semiestruturadas serão analisadas através do método do Discurso do Sujeito Coletivo que permite definir expressões-chave de cada depoimento e extrair ideias centrais fundamentais ao conteúdo descritivo verbalizado pelos sujeitos. O projeto de pesquisa foi aprovado pelo Comitê de Ética em Pesquisa da Universidade do Estado do Rio Grande do Norte (Protocolo 067/2010). Resultados Esperados: conhecer a assistência prestada às nutrizes pelo enfermeiro durante o pré-natal e os quatro primeiros meses pós-parto, possibilitando avaliar de que forma acontece o apoio ao aleitamento materno exclusivo na Estratégia Saúde da Família do município. Esses resultados poderão indicar caminhos de reflexão acerca da prática de enfermagem ao processo de amamentação e sugerir estratégias de superação das dificuldades enfrentadas na prática promocional ao aleitamento materno exclusivo.
Functional Polysaccharide Composite Nanoparticles from Cellulose Acetate and Potential Applications
Authors: Kulterer Martin R. , Reichel Victoria E. , Kargl Rupert , Köstler Stefan , Sarbova Velina , Heinze Thomas , Stana‐Kleinschek Karin , Ribitsch Volker
Published: February 2012

An in situ technique for preparing composite nanoparticles from hydrophobic cellulose acetate and hydrophilic polysaccharides using nanoprecipitation is presented. This technique allows the nanoparticles’ surface properties to be tuned very specifically. Spherical, narrow‐size‐distributed composite nanoparticles of different size, charge, functionality, and increased stability can be generated by using hydroxyethyl cellulose, carboxymethyl cellulose, low molecular weight chitosan, and amino cellulose. The influence of the pH and hydrophilic polysaccharide content in the particle formation is shown. The pH‐ and ionic strength‐ effective zeta‐potential functions are evidence of the presence of functional polysaccharides at the nanoparticle surface. The in situ technique is compared with the adsorption of hydrophilic polysaccharides onto cellulose acetate nanoparticles in two steps. The great potential of in situ prepared composite nanoparticles in the pharmaceutical industry and bio‐ or food technology, as carriers of hydrophobic substances in aqueous media and for specific surface modifications, e.g., to selectively introduce strong antimicrobial properties, is illustrated.
Improving the water resistance of biodegradable collagen films
Authors: Sommer Isabell , Kunz Peter M.
Published: February 2012

Although collagen‐based films have been successfully used for packaging in the meat industry, their potential as a replacement for synthetic packaging films in other industries has not yet been widely investigated. This may be due to the low water resistance of protein films. The objective of this study was to systematically improve water resistance in collagen‐based films and to investigate the influence of different crosslinking agents and crosslinker concentration levels. In this study, the film's water resistance was determined gravimetrically as well as by applying the Sircol™ Protocol. Although the reference collagen film produced without any crosslinking agents showed to have almost completely disintegrated after 2 h at 80°C, it was possible to generate chemically crosslinked films, which stayed intact after 2 h at 80°C and even maintained water resistance after 8 h at 60°C. The results of this study showed that thermal crosslinking leads to weaker bonds than the chemically crosslinking. Both assay methods for the determination of the water resistance yielded almost identical curves, except for films with an added plasticizer, clarifying that the Sircol™ protocol is not suitable to record data as a result of the dissipation of the plasticizer. Furthermore, study results indicated that the water resistance strongly depends on the amount of added crosslinker and reaches a maximum at a concentration of 10% w/w, whereas compostability was nearly 90% at 58°C within 38 days for a chemically crosslinked collagen film plasticized with lecithin. However, increased crosslinking significantly decreased the enzymatic degradability of the investigated films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Photo‐cured organic–inorganic hybrid composites of acrylated castor oil and methacrylate‐substituted polysilsesquioxane
Authors: Shibata Mitsuhiro , Obara Syotarou
Published: February 2012

Acrylated castor oil (ACO) was synthesized by the reaction of castor oil and acryloyl chloride in the presence of triethylamine. The 1H‐NMR and Fourier transform infrared spectral analyses of ACO showed that the hydroxy groups of castor oil are completely esterified and that the number of acrylate groups per triglyceride is 2.56. The ACO was photo‐cured with methacrylate‐substituted polysilsesquioxane (ME‐PSQ) prepared from 3‐(trimethoxysilyl)propyl methacrylate and tetramethylammonium hydroxide in the ACO/ME‐PSQ weight ratio of 20/0, 20/1, 20/2, and 20/3. Although the mechanical reinforcement effect by the incorporation of PSQ frameworks was observed when evaluated from dynamic mechanical analysis and flexural test, the reinforcement effect showed a tendency to decline with a higher ME‐PSQ content. The TEM observation revealed that the PSQ is homogeneously distributed in the matrix for the cured ACO/ME‐PSQ (20/1), while some aggregated particles of the PSQ were observed for the cured AC/ME‐PSQ (20/2). The 5% weight loss temperature of the cured ACO/ME‐PSQ rose with ME‐PSQ content. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New Catalytic Approaches towards the Enantioselective Halogenation of Alkenes
Authors: Hennecke Ulrich
Published: February 2012

The addition of electrophilic reagents to the carbon–carbon double bond is one of the most fundamental reactions in organic chemistry. Halogen electrophiles constitute probably the most important class of electrophiles and have been widely used to induce electrophilic addition reactions to alkenes like halolactonizations or dihalogenations. Despite their long history and high importance, catalytic, asymmetric variants of these reactions have been underdeveloped until very recently. During the last two years this has changed and many novel approaches have been reported. This review aims to cover these new developments through discussing the common themes as well as the suggested mechanistic scenarios.
Highly Dispersed Platinum Nanoparticles on TiO2 Prepared by Using the Microwave‐Assisted Deposition Method: An Efficient Photocatalyst for the Formation of H2 and N2 from Aqueous NH3
Authors: Fuku Kojirou , Kamegawa Takashi , Mori Kohsuke , Yamashita Hiromi
Published: February 2012

A simple and practical technique to synthesize nanosized platinum particles loaded on TiO2 (Pt–TiO2) by using a microwave (Mw)‐assisted deposition method has been exploited in the development of a highly efficient photocatalyst for the formation of H2 and N2 gases from harmful nitrogen‐containing chemical wastes, for example, aqueous ammonia (NH3). Upon Mw irradiation, a platinum precursor can be deposited quickly on the TiO2 surface from an aqueous solution of platinum and subsequent reduction with H2 affords the nanosized platinum metal particles with a narrow size distribution (Mw‐Pt–TiO2). Characterization by CO adsorption, platinum LIII‐edge X‐ray absorption fine structure analysis, and TEM analysis revealed that the size of the metal nanoparticles strongly depended on the preparation methods. Smaller platinum nanoparticles were obtained by the Mw heating method than those obtained by conventional preparation techniques, such as photoassisted deposition (PAD), impregnation (Imp), and equilibrium adsorption (EA) deposition by conventional convective heating. The H2 and N2 formation rates increased with increasing dispersity of platinum. Pt–TiO2 prepared by the Mw heating method exhibited a specifically high H2 formation activity in the photocatalytic decomposition of aqueous NH3 in a nearly stoichiometric 3:1 (H2/N2) molar ratio under inert conditions. The present Mw heating method is applicable to a variety of anatase‐type TiO2 species possessing different specific surface areas to provide small and highly dispersed platinum nanoparticles with a narrow size distribution.
Exploring self‐optimization and self‐stabilization properties in bio‐inspired autonomic cloud applications
Authors: Champrasert Paskorn , Suzuki Junichi , Lee Chonho
Published: February 2012

This paper describes an architecture to build self‐optimizable and self‐stabilizable cloud applications. The design of the proposed architecture, SymbioticSphere, is inspired by key biological principles such as decentralization, evolution, and symbiosis. In SymbioticSphere, each cloud application consists of application services and middleware platforms. Each service and platform is designed as a biological entity and implements biological behaviors such as energy exchange, migration, reproduction, and death. Each service/platform possesses behavior policies, as genes, each of which governs when to and how to invoke a particular behavior. SymbioticSphere allows services and platforms to autonomously adapt to dynamic network conditions by optimizing their behavior policies with a multiobjective genetic algorithm. Moreover, SymbioticSphere allows services and platforms to autonomously seek stable adaptation decisions as equilibria (or symbiosis) between them with a game theoretic algorithm. This symbiosis augments evolutionary optimization to expedite the adaptation of agents and platforms. It also contributes to stable performance that contains very limited amounts of fluctuations. Simulation results demonstrate that agents and platforms successfully attain self‐optimization and self‐stabilization properties in their adaptation process. Copyright © 2012 John Wiley & Sons, Ltd.
Alternative strategies of seed predator escape by early‐germinating oaks in Asia and North America
Authors: Yi Xianfeng , Yang Yueqin , Curtis Rachel , Bartlow Andrew W. , Agosta Salvatore J. , Steele Michael A.
Published: February 2012

Early germination of white oaks is widely viewed as an evolutionary strategy to escape rodent predation; yet, the mechanism by which this is accomplished is poorly understood. We report that chestnut oak Quercus montana (CO) and white oak Q. alba (WO) (from North America), and oriental cork oak Q. variabilis (OO) and Mongolian oak Q. mongolica (MO) (from Asia) can escape predation and successfully establish from only taproots. During germination in autumn, cotyledonary petioles of acorns of CO and WO elongate and push the plumule out of the cotyledons, whereas OO and MO extend only the hypocotyls and retain the plumule within the cotyledons. Experiments showed that the pruned taproots (>6 cm) of CO and WO acorns containing the plumule successfully germinated and survived, and the pruned taproots (≥12 cm) of OO and MO acorns without the plumule successfully regenerated along with the detached acorns, thus producing two seedlings. We argue that these two distinct regeneration morphologies reflect alternative strategies for escaping seed predation.
Influence of gem‐Dimethyl Substitution on the Stability, Kinetics and Relaxometric Properties of PDTA Complexes
Authors: Forgács Attila , Giovenzana Giovanni B. , Botta Mauro , Brücher Ernő , Tóth Imre , Baranyai Zsolt
Published: February 2012

The protonation constants of DMPDTA (H4DMPDTA = 2,2‐dimethylpropylenediamine‐N,N,N′,N′‐tetraacetic acid) and the stability and protonation constants of its Ln3+ and some divalent metal complexes have been determined by pH potentiometry and spectrophotometry (Cu2+) and compared with the corresponding properties of the complexes formed with PDTA (H4PDTA = propylenediamine‐N,N,N′,N′‐tetraacetic acid). The log K2H value of DMPDTA is lower by 1.5 log K units than that of PDTA. The stability constants (log KML) of the Ln3+ complexes formed with DMPDTA are lower by 1.0–1.5 log K units than those of PDTA. The kinetics of the transmetallation reactions of Gd(DMPDTA)– and Gd(PDTA)– with Cu2+ and Eu3+ have been studied by spectrophotometry. The reactions with Cu2+ and Eu3+ occur predominantly by spontaneous and proton‐assisted dissociation of the Gd(DMPDTA)– and Gd(PDTA)– complexes. The rates of the metal‐exchange reactions of Gd(DMPDTA)– are significantly lower than those of Gd(PDTA)–. The presence of the two methyl groups on the ligand backbone increases the kinetic inertness of Gd(DMPDTA)– due to the higher conformational rigidity of DMPDTA. Temperature‐dependent 17O NMR spectra and 1/T1 1H nuclear magnetic relaxation dispersion profiles of the Gd3+ complexes were measured and analyzed to obtain the parameters that influence the water exchange rate and rotational dynamics.
The effect of wind averaging time on wind erosivity estimation
Authors: Guo Zhongling , Zobeck Ted M. , Stout John E. , Zhang Keli
Published: February 2012

The Wind Erosion Prediction System (WEPS) and Revised Wind Erosion Equation (RWEQ) are widely used for estimating wind‐induced soil erosion at a field scale. Wind is the principal erosion driver in the two models. Wind erosivity, which describes the capacity of wind to cause soil erosion, is defined as erosive wind power density (WPD) in WEPS, and wind value (W) in RWEQ. In this study, the daily average WPD (AWPD) and the daily average W (Wf) were chosen to investigate the effect of averaging time on wind erosivity estimation based on observed wind data. We compare the daily AWPD and Wf calculated from 1, 5, 10, 15, 30, and 60 minute average wind speed data.

The results of comparisons indicate that averaging wind speed can significantly influence estimates of wind erosivity. Compared with the daily AWPD and Wf calculated from one minute average wind speed data, all daily AWPD and Wf values calculated from 5, 10, 15, 30, and 60 minute averaged wind speeds tend to be significantly lower than values calculated from one minute values. In general, longer averaging times tend to produce smaller values of daily AWPD or Wf, which may lead to an under‐estimation of wind erosion. Further studies are needed to extend and apply the findings obtained in this study to actual wind erosion predictions. Copyright © 2012 John Wiley & Sons, Ltd.
Effects of soil compaction, rain exposure and their interaction on soil carbon dioxide emission
Authors: Novara Agata , Armstrong Alona , Gristina Luciano , Semple Kirk T. , Quinton John N.
Published: February 2012

Soils release more carbon, primarily as carbon dioxide (CO2), per annum than current global anthropogenic emissions. Soils emit CO2 through mineralization and decomposition of organic matter and respiration of roots and soil organisms. Given this, the evaluation of the effects of abiotic factors on microbial activity is of major importance when considering the mitigation of greenhouse gases emissions. Previous studies demonstrate that soil CO2 emission is significantly affected by temperature and soil water content. A limited number of studies have illustrated the importance of bulk density and soil surface characteristics as a result of exposure to rain on CO2 emission, however, none examine their relative importance. Therefore, this study investigated the effects of soil compaction and exposure of the soil surface to rainfall and their interaction on CO2 release. We conducted a factorial laboratory experiment with three soil types after sieving (clay, silt and sand soil), three different bulk densities (1·1 g cm–3, 1·3 g cm–3, 1·5 g cm–3) and three different exposures to rainfall (no rain, 30 minutes and 90 minutes of rainfall). The results demonstrated CO2 release varied significantly with bulk density, exposure to rain and time. The relationship between rain exposure and CO2 is positive: CO2 emission was 53% and 42% greater for the 90 minutes and 30 minutes rainfall exposure, respectively, compared to those not exposed to rain. Bulk density exhibited a negative relationship with CO2 emission: soil compacted to a bulk density of 1·1 g cm–3 emitted 32% more CO2 than soil compacted to 1·5 g cm–3. Furthermore we found that the magnitude of CO2 effluxes depended on the interaction of these two abiotic factors. Given these results, understanding the influence of soil compaction and raindrop impact on CO2 emission could lead to modified soil management practices which promote carbon sequestration. Copyright © 2012 John Wiley & Sons, Ltd.
Should bedside sonography be used first to diagnose pneumothorax secondary to blunt trauma?
Authors: Donmez Halil , Tokmak Turgut Tursem , Yildirim Afra , Buyukoglan Hakan , Ozturk Mehmet , Yaşar Ayaz Ümit , Mavili Ertugrul
Published: February 2012

Background.

Our purpose was to evaluate the effectiveness of bedside sonography (US) in the detection of pneumothorax secondary to blunt thoracic trauma.

Methods.

In this prospective study, 240 hemithoraces of 120 consecutive patients with multiple trauma were evaluated with chest radiographs (CXR) and bedside thoracic US for the diagnosis of pneumothorax. CT examinations were performed in 68 patients. Fifty‐two patients who did not undergo CT examinations were excluded from the study. US examinations were performed independently at bedside by two radiologists who were not informed about CXR and CT findings. CXRs were interpreted by two radiologists who were unaware of the US and CT results. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CXR and US were calculated.

Results.

One hundred thirty‐six hemithoraces were assessed in 68 patients. A total of 35 pneumothoraces were detected in 33 patients. On US, the diagnosis of pneumothorax was correct in 32 hemithoraces. In 98 hemithoraces without pneumothorax, US was normal. With US examination, there were three false‐positive and three false‐negative results. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of US were 91.4%, 97%, 91.4%, 97%, and 97%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CXR were 82.7%, 89.7%, 68.5%, 95%, and 89.5%, respectively.

Conclusions.

Bedside thoracic US is an accurate method that can be used in trauma patients instead of CXR for the detection of pneumothorax. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012
Structure and Morphology of New Bio‐Based Thermoplastic Polyurethanes Obtained From Dimeric Fatty Acids
Authors: Bueno‐Ferrer Carmen , Hablot Elodie , Perrin‐Sarazin Florence , Garrigós M. Carmen , Jiménez Alfonso , Averous Luc
Published: February 2012

Bio‐based TPUs from dimer acid‐based polyols are synthesised by using a two‐step prepolymer process including reactive processing. The effect of the polyol on the final chemical structures, morphologies and properties of bio‐based TPUs is evaluated by different analytical techniques. It is observed that the percentage of hard segment (HS) distributed in organised and unorganised phases is a key factor to control the materials properties. DSC reveals that the percentages of HS dispersed in the soft domains are high at low experimental HS contents. Multiscale microscopies show better defined organised structures with increasing HS content in TPUs, highlighting the importance of the distribution between hard and soft segments in the material structure.

magnified image
A finite element approach to the simulation of hydraulic fractures with lag
Authors: Hunsweck Michael J. , Shen Yongxing , Lew Adrian J.
Published: February 2012

We presented a finite‐element‐based algorithm to simulate plane‐strain, straight hydraulic fractures in an impermeable elastic medium. The algorithm accounts for the nonlinear coupling between the fluid pressure and the crack opening and separately tracks the evolution of the crack tip and the fluid front. It therefore allows the existence of a fluid lag. The fluid front is advanced explicitly in time, but an implicit strategy is needed for the crack tip to guarantee the satisfaction of Griffith's criterion at each time step. We enforced the coupling between the fluid and the rock by simultaneously solving for the pressure field in the fluid and the crack opening at each time step. We provided verification of our algorithm by performing sample simulations and comparing them with two known similarity solutions. Copyright © 2012 John Wiley & Sons, Ltd.
Blossom‐Quad: A non‐uniform quadrilateral mesh generator using a minimum‐cost perfect‐matching algorithm
Authors: Remacle J.‐F. , Lambrechts J. , Seny B. , Marchandise E. , Johnen A. , Geuzainet C.
Published: February 2012

A new indirect way of producing all‐quad meshes is presented. The method takes advantage of a well‐known algorithm of the graph theory, namely the Blossom algorithm, that computes the minimum‐cost perfect matching in a graph in polynomial time. The new Blossom‐Quad algorithm is compared with standard indirect procedures. Meshes produced by the new approach are better both in terms of element shape and in terms of size field efficiency. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of Grapefruit Juice and Ritonavir on Pharmacokinetics of Lopinavir in Wistar Rats
Authors: Ravi P. R. , Vats R. , Thakur R. , Srivani S. , Aditya N.
Published: February 2012

Lopinavir (LPV), a newer HIV protease inhibitor, has poor bioavailability being a substrate of both cytochrome P450 3A enzyme system (CYP3A) and permeability‐glycoprotein (P‐gp). Ritonavir (RTV) is a known inhibitor of both P‐gp and CYP3A and is co‐administered with LPV in anti‐HIV therapy. Grapefruit juice (GFJ) is known to inhibit CYP3A and has conflicting effects, ranging from activation to inhibition, on P‐gp. In this research work, the effects of GFJ and RTV on the pharmacokinetics of LPV were compared in rats. A mechanistic evaluation was undertaken using various in vitro and ex vivo studies to support the in vivo pharmacokinetic data. The plasma levels of LPV were found to increase significantly upon co‐administration with GFJ in single dose as well as multidose pretreatment studies. Similar, but marginally higher, results were observed upon co‐administration of LPV with RTV. No significant change in tmax was observed in the various treatment groups. The apparent permeability of LPV in the ileum increased significantly after the pre‐incubation with GFJ and RTV compared with no pre‐incubation. The GFJ and RTV showed a significant and similar inhibitory effect on rat intestinal microsomes in the metabolism of LPV. The GFJ was equally effective as RTV in increasing the bioavailability of LPV. Copyright © 2012 John Wiley & Sons, Ltd.
Online Calibration Methods for the DINA Model with Independent Attributes in CD-CAT
Authors: Chen Ping , Xin Tao , Wang Chun , Chang Hua-Hua
Published: February 2012

Item replenishing is essential for item bank maintenance in cognitive diagnostic computerized adaptive testing (CD-CAT). In regular CAT, online calibration is commonly used to calibrate the new items continuously. However, until now no reference has publicly become available about online calibration for CD-CAT. Thus, this study investigates the possibility to extend some current strategies used in CAT to CD-CAT. Three representative online calibration methods were investigated: Method A (Stocking in Scale drift in on-line calibration. Research Rep. 88-28, 1988), marginal maximum likelihood estimate with one EM cycle (OEM) (Wainer & Mislevy In H. Wainer (ed.) Computerized adaptive testing: A primer, pp. 65–102, 1990) and marginal maximum likelihood estimate with multiple EM cycles (MEM) (Ban, Hanson, Wang, Yi, & Harris in J. Educ. Meas. 38:191–212, 2001). The objective of the current paper is to generalize these methods to the CD-CAT context under certain theoretical justifications, and the new methods are denoted as CD-Method A, CD-OEM and CD-MEM, respectively. Simulation studies are conducted to compare the performance of the three methods in terms of item-parameter recovery, and the results show that all three methods are able to recover item parameters accurately and CD-Method A performs best when the items have smaller slipping and guessing parameters. This research is a starting point of introducing online calibration in CD-CAT, and further studies are proposed for investigations such as different sample sizes, cognitive diagnostic models, and attribute-hierarchical structures.
When a product takes on characteristics of the person who created it: Sometimes it sounds sweeter
Authors: Folkes Valerie S. , Matta Shashi
Published: February 2012

We investigated when consumers' judgments about a product reflect information about its product source (the person who creates the product). Three experiments manipulated congruence between the source's gender and the gender‐typing of the source's product. When congruent with expectations (a male conductor played male‐typed music), pre‐trial source information had the same effect on post‐trial product judgments as when source information was absent. Incongruence (a female conductor played male‐typed music) distorted product attribute judgments when the source's competence was questioned. Her music was judged to be more delicate, less powerful and worse quality than his. This process of product experience being assimilated into incompetence stereotypes required minimal cognitive resources. When the incongruent source was undoubtedly competent, the amount of experiential evidence about an attribute influenced distortion. Consumers judged powerful music as powerful regardless of conductor gender, but, lacking much evidence about its delicacy, judged hers as more delicate than his. The selective effect of source gender information reflects consumers' cognitively effortful hypothesis testing of beliefs that gender expresses itself in a person's output against experiential evidence.