bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolutionary reputation model for node selfishness resistance in opportunistic networks
Authors: Zhang Sihai , Qiu Hongyang , Liu Yuan , Zhou Wuyang 
Published: November 2011

SUMMARYSelfish behavior of nodes in opportunistic networks impact greatly on the network performance. Therefore, an effective mechanism should be proposed to resist such misbehavior and to stimulate the nodes willing to relay packets for other nodes toward their destinations. On the basis of the evolutionary reputation model proposed, this paper investigates the network performance, including message delivery ratio, average delivery delay, and average intermittent hops, under the influence of reputation degree and selfish degree. In addition, the reputation evolution process is described, which helps to understand the interaction among network nodes. Simulation results show that the opportunistic network adopting the model proposed can resist partially the node selfishness and maintain acceptable network performance. Copyright © 2011 John Wiley & Sons, Ltd.
A study of parallel tuner with voltage‐dependent capacitance
Authors: Eskandarian Abdollah 
Published: November 2011

SUMMARYA study of varactor tuned LC circuits is presented. Nonlinear time domain circuit differential equation is rewritten in terms of phase plane variables, which can then be solved in closed form. General expressions are derived, which are applicable to any capacitance–voltage relationship. Two types of circuit structures, namely single‐ended and balanced, with MOS diodes as the variable capacitance elements, are specifically considered. The nature of the voltage waveforms across the two circuits is determined by phase plane plots. Variation of voltage with time is calculated numerically. It is shown that the voltage waveform for the single‐ended circuit is asymmetric, with higher harmonics present. Furthermore, the fundamental resonant frequency is dependent on amplitude of oscillation and could decrease to 94% of its small signal value for large voltage swings. Near 34% control over frequency is calculated, for a bias voltage range of 8 to 1. On the other hand, the balanced structure results in symmetric voltage waveform, with negligible harmonic content. Dependence of frequency on amplitude is weak, only decreasing to 98% of its small signal value, for the largest swings. The tuning range is marginally improved by the balanced structure. The results are compared with those obtained from Fourier‐based calculations and experimental data in literature, and good agreement is obtained. Copyright © 2011 John Wiley & Sons, Ltd.
Role of Hedgehog signalling at the transition from double‐positive to single‐positive thymocyte
Authors: Furmanski Anna L. , Saldana Jose Ignacio , Rowbotham Nicola J. , Ross Susan E. , Crompton Tessa 
Published: November 2011

AbstractIn the thymus, developing T cells receive signals that determine lineage choice, specificity, MHC restriction and tolerance to self‐antigen. One way in which thymocytes receive instruction is by secretion of Sonic hedgehog (Shh) from thymic epithelial cells. We have previously shown that Hedgehog (Hh) signalling in the thymus decreases the CD4:CD8 single‐positive (SP) thymocyte ratio. Here, we present data indicating that double‐positive (DP) thymocytes are Hh‐responsive and that thymocyte‐intrinsic Hh signalling plays a role in modulating the production of CD4+ (SP4), CD8+ (SP8) and unconventional T‐cell subsets. Repression of physiological Hh signalling in thymocytes altered the proportions of DP and SP4 cells. Thymocyte‐intrinsic Hh‐dependent transcription also attenuated both the production of mature SP4 and SP8 cells, and the establishment of peripheral T‐cell compartments in TCR‐transgenic mice. Additionally, stimulation or withdrawal of Hh signals in the WT foetal thymus impaired or enhanced upregulation of the CD4 lineage‐specific transcription factor Gata3 respectively. These data together suggest that Hh signalling may play a role in influencing the later stages of thymocyte development.
Half of the T‐cell repertoire combinatorial diversity is genetically determined in humans and humanized mice
Authors: Pham Hang‐Phuong , Manuel Manuarii , Petit Nicolas , Klatzmann David , Cohen‐Kaminsky Sylvia , Six Adrien , Marodon Gilles 
Published: November 2011

AbstractIn humanized mice, the T‐cell repertoire is derived from genetically identical human progenitors in distinct animals. Thus, careful comparison of the T‐cell repertoires of humanized mice with those of humans may reveal the contribution of genetic determinism on T‐cell repertoire formation. Here, we performed a comprehensive assessment of the distribution of V‐J combinations of the human β chain of the T‐cell receptor (hTRBV) in NOD.SCID.γc−/− (NSG) humanized mice. We observed that numerous V‐J combinations were equally distributed in the thymus and in the periphery of humanized mice compared with human references. A global analysis of the data, comparing repertoire perturbation indices in humanized NSG mice and unrelated human PBMCs, reveals that 50% of the hTRBV families significantly overlapped. Using multivariate ranking and bootstrap analyses, we found that 18% of all possible V‐J combinations contributed close to 50% of the expressed diversity, with significant over‐representation of BV5‐J1.1+1.2 and BV6‐J1.1+1.2 rearrangements. Finally, comparison of CD3− and CD3+ thymocyte repertoires indicated that the observed V‐J combination overlap was already present before TCR‐MHC selection in the thymus. Altogether, our results show that half of the T‐cell repertoire combinatorial diversity in humans is genetically determined.
Dyes That Bear Thiazolylazo Groups as Chromogenic Chemosensors for Metal Cations
Authors: Ábalos Tatiana , Moragues María , Royo Santiago , Jiménez Diego , Martínez‐Máñez Ramón , Soto Juan , Sancenón Félix , Gil Salvador , Cano Joan 
Published: November 2011

AbstractA family of dyes (L1–L6) that contain a thiazolylazo group as signalling subunit and several macrocyclic cavities with different ring sizes and type and number of heteroatoms as binding sites has been synthesized and characterized. Solutions of L1–L6 in acetonitrile show broad and structureless absorption bands in the 554–577 nm range with typicalmolar absorption coefficients that range from 20000 to 32000 M–1 cm–1. A detailed protonation study was carried out with solutions of L1, L2 and L5 in acetonitrile. Addition of one equivalent of protons to L1 and L2 resulted in the development of a new band at 425 and 370 nm, respectively, which was ascribed to protonation in the aniline nitrogen. In contrast, protonation of L5 resulted in a bathochromic shift of 25 nm of the absorption band that was conceivable with protonation of one of the nitrogen atoms of the azo moiety. These results were in agreement with 1H NMR spectroscopic data. Theoretical studies on the model ligand L1 and on different possible protonation species were also performed by using density functional theory (DFT) quantum mechanical calculations. Colour modulations in solutions of L1–L6 in acetonitrile in the presence of the metal cations Fe3+, Ni2+, Zn2+, Cd2+, Pb2+ and Hg2+ have been studied. A selective chromogenic response of L4 in the presence of Pb2+ and L5 in the presence of Hg2+ was observed. To get a better insight into the chromophoric nature in the presence of metal cations, the interaction of Hg2+ with the model compound L1 in two different coordination modes was studied theoretically by using density functional theory (DFT) quantum mechanical calculations.
In vivo biocompatibility and in vitro characterization of poly‐lactide‐co‐glycolide structures containing levetiracetam, for the treatment of epilepsy
Authors: Halliday Amy J. , Campbell Toni E. , Razal Joselito M. , McLean Karen J. , Nelson Timothy S. , Cook Mark J. , Wallace Gordon G. 
Published: November 2011

AbstractEpilepsy is a chronic neurological disorder characterized by recurrent seizures, and is highly resistant to medication with up to 40% of patients continuing to experience seizures whilst taking oral antiepileptic drugs. Recent research suggests that this may be due to abnormalities in the blood–brain barrier, which prevent the passage of therapeutic substances into the brain. We sought to develop a drug delivery material that could be implanted within the brain at the origin of the seizures to release antiepileptic drugs locally and avoid the blood brain barrier. We produced poly‐lactide‐co‐glycolide drop‐cast films and wet‐spun fibers loaded with the novel antiepileptic drug Levetiracetam, and investigated their morphology, in vitro drug release characteristics, and brain biocompatibility in adult rats. The best performing structures released Levetiracetam constantly for at least 5 months in vitro, and were found to be highly brain biocompatible following month‐long implantations in the motor cortex of adult rats. These results demonstrate the potential of polymer‐based drug delivery devices in the treatment of epilepsy and warrant their investigation in animal models of focal epilepsy. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Injectable polyurethane composite scaffolds delay wound contraction and support cellular infiltration and remodeling in rat excisional wounds
Authors: Adolph Elizabeth J. , Hafeman Andrea E. , Davidson Jeffrey M. , Nanney Lillian B. , Guelcher Scott A. 
Published: November 2011

AbstractInjectable scaffolds present compelling opportunities for wound repair and regeneration because of their ability to fill irregularly shaped defects and deliver biologics such as growth factors. In this study, we investigated the properties of injectable polyurethane (PUR) biocomposite scaffolds and their application in cutaneous wound repair using a rat excisional model. The scaffolds have a minimal reaction exotherm and clinically relevant working and setting times. Moreover, the biocomposites have mechanical and thermal properties consistent with rubbery elastomers. In the rat excisional wound model, injection of settable biocomposite scaffolds stented the wounds at early time points, resulting in a regenerative rather than a scarring phenotype at later time points. Measurements of wound length and thickness revealed that the treated wounds were less contracted at day 7 compared to blank wounds. Analysis of cell proliferation and apoptosis showed that the scaffolds were biocompatible and supported tissue ingrowth. Myofibroblast formation and collagen fiber organization provided evidence that the scaffolds have a positive effect on extracellular matrix remodeling by disrupting the formation of an aligned matrix under elevated tension. In summary, we have developed an injectable biodegradable PUR biocomposite scaffold that enhances cutaneous wound healing in a rat model. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Deproteinization technique stabilizes the adhesion of the fiberglass post relined with resin composite to root canal
Authors: Cecchin Doglas , Almeida José F. A. , Gomes Brenda P. F. A. , Zaia Alexandre A. , Ferraz Caio C. R. 
Published: November 2011

AbstractTo evaluate the effects of pretreatment of root dentin by 5.25% sodium hypochlorite (NaOCl) alone, associated with 2% chlorhexidine in gel base (CHX) and/or ethanol (EtOH), and the air‐drying technique (Air) on the bond strength and adhesive durability of fiberglass post relined with resin composite to root dentin. A total of 100 bovine incisor roots were divided into 10 groups: G1 (control), irrigation with physiologic solution; G2, Air; G3, NaOCl; G4, NaOCl + Air; G5, NaOCl + EtOH; G6, NaOCl + EtOH + Air; G7, NaOCl + CHX; G8, NaOCl + CHX + Air; G9, NaOCl + CHX + EtOH; G10, NaOCl + CHX + EtOH + Air. Fiberglass post relined with resin composite was cemented and each group was randomly divided into two subgroups: 24 h of water storage and 12 months of water storage. The push‐out test was performed and bond strength values were analyzed by ANOVA and Tukey's test. The use of NaOCl alone or associated with CHX had the highest values of bond strength with or without Air in the immediate and stored groups, being statistically similar to the immediate control group (p > 0.05). The groups using EtOH or Air alone had lower bond strength in the immediate and stored groups (p < 0.05). A significant decrease with the time of the bond strength in the control group was observed after 12 months of storage (p > 0.05). The use of NaOCl or NaOCl associated with CHX preserved the bond strength immediate and for 12 months. The air‐drying technique and the other associations decreased the immediate bond strength values. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 577–583, 2012.
Strontium‐loaded mineral bone cements as sustained release systems: Compositions, release properties, and effects on human osteoprogenitor cells
Authors: Tadier Solène , Bareille Reine , Siadous Robin , Marsan Olivier , Charvillat Cédric , Cazalbou Sophie , Amédée Joelle , Rey Christian , Combes Christèle 
Published: November 2011

AbstractThis study aims to evaluate in vitro the release properties and biological behavior of original compositions of strontium (Sr)‐loaded bone mineral cements. Strontium was introduced into vaterite CaCO3‐dicalcium phosphate dihydrate cement via two routes: as SrCO3 in the solid phase (SrS cements), and as SrCl2 dissolved in the liquid phase (SrL cements), leading to different cement compositions after setting. Complementary analytical techniques implemented to thoroughly investigate the release/dissolution mechanism of Sr‐loaded cements at pH 7.4 and 37°C during 3 weeks revealed a sustained release of Sr and a centripetal dissolution of the more soluble phase (vaterite) limited by a diffusion process. In all cases, the initial burst of the Ca and Sr release (highest for the SrL cements) that occurred over 48 h did not have a significant effect on the expression of bone markers (alkaline phosphatase, osteocalcin), the levels of which remained overexpressed after 15 days of culture with human osteoprogenitor (HOP) cells. At the same time, proliferation of HOP cells was significantly higher on SrS cements. Interestingly, this study shows that we can optimize the sustained release of Sr2+, the cement biodegradation and biological activity by controlling the route of introduction of strontium in the cement paste. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 378–390, 2012.
Antimicrobial acrylic materials with in situ generated silver nanoparticles
Authors: Oei James D. , Zhao William W. , Chu Lianrui , DeSilva Mauris N. , Ghimire Abishek , Rawls H. Ralph , Whang Kyumin 
Published: November 2011

AbstractPolymethyl methacrylate (PMMA) is widely used to treat traumatic head injuries (cranioplasty) and orthopedic injuries (bone cement), but there is a problem with implant‐centered infections. With organisms such as Acinetobacter baumannii and methicillin‐resistant staphylococcus aureus developing resistance to antibiotics, there is a need for novel antimicrobial delivery mechanisms without risk of developing resistant organisms. Objectives: To develop a novel antimicrobial implant material by generating silver nanoparticles (AgNP) in situ in PMMA. Results: All PMMA samples with AgNP's (AgNP‐PMMA) released Ag+ ions in vitro for over 28 days. In vitro antimicrobial assays revealed that these samples (even samples with the slowest release rate) inhibited 99.9% of bacteria against four different strains of bacteria. Long‐term antimicrobial assay showed a continued antibacterial effect past 28 days. Some AgNP‐loaded PMMA groups had comparable Durometer‐D hardness (a measure of degree of cure) and modulus to control PMMA, but all experimental groups had slightly lower ultimate transverse strengths. Conclusions: AgNP‐PMMA demonstrated a tremendously broad‐spectrum and long‐intermediate‐term antimicrobial effect with comparable mechanical properties to control PMMA. Current efforts are focused on further improving mechanical properties by reducing AgNP loading and assessing fatigue properties. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 409–415, 2012.
Effect of fatigue on fracture toughness and phase transformation of Y‐TZP ceramics by X‐ray diffraction and Raman spectroscopy
Authors: Nemli Seçil Karakoca , Yilmaz Handan , Aydin Cemal , Bal Bilge Turhan , Tıraş Tülay 
Published: November 2011

AbstractThe aim of this study was to evaluate the effect of fatigue on fracture toughness and phase transformation of yttria‐stabilized zirconia polycrystal materials (Cercon and Lava). The specimens were tested for indentation fracture toughness either with or without being subjected to fatigue (20,000 cycles, 2 Hz, 200 N load). X‐ray diffraction (XRD) analysis was used to examine the phase composition of specimens. The indentation images were analyzed using Raman spectroscopy at indentation center (p1), indentation corner (p2), points on crack 100 μm (p3), and 200 μm (p4) away from the corner and a point ∼80 μm away from the crack (p5). Fracture toughness results were statistically analyzed by two‐way analysis of variance (ANOVA); XRD and Raman spectroscopy results were analyzed by three‐way ANOVA. Fracture toughness of Cercon control (CC) and fatigue (CF) groups were 6.8 and 6.9 MPa√m, respectively, with no significant difference (p> 0.01). Fracture toughness of Lava fatigue (LF; 7.3 MPa√m) was significantly higher than Lava control (LC;p< 0.01). XRD analyses showed CC and LC consisted of tetragonal zirconia, monoclinic zirconia detected after fatigue. After indentation, relative amount of monoclinic phase significantly increased in CC, CF, and LC; decreased in LF. The Raman spectroscopy results indicated that monoclinic fraction was the highest at p2, subsequently at p1 and decreased at p3, p4, and p5 for all groups. Mechanical cycling increased fracture toughness of Cercon and Lava, the second being significant. Phase transformation was also detected after fatigue, which is higher in Lava. Analysis of indentations showed that transformation was highest was at the corner, second at center. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 416–424, 2012.
Colorless and high strength MgO/Al2O3/SiO2 glass–ceramic dental material using zirconia as nucleating agent
Authors: Dittmer Marc , Rüssel Christian 
Published: November 2011

AbstractGlasses in the system of MgO/Al2O3/SiO2 with different concentrations of zirconia as nucleating agent, some of them additionally doped with ZnO or P2O5, were annealed in a temperature range from 950 to 1150°C. The use of zirconia led to colorless glass–ceramics, which were transparent to opaque. In all studied compositions, α‐/β‐quartz‐solid‐solutions, zirconia as well as spinel or gahnite (ZnAl2O4)/spinel‐solid‐solution precipitated. The highest bending strength of 475 MPa was obtained after annealing at 1000°C for 3 h. The increase of the annealing temperature or an increase in the zirconia concentration resulted in an increase of the microhardness up to 13.3 GPa and of the fracture toughness up to 2.7 MPa m1/2. The addition of ZnO results in an increase of the hardness up to 12.5 GPa. The addition of ZnO or P2O5 led to a fracture toughness of 2 MPa m1/2. The described physical properties had to be highly advantageous for the preparation of colorless high strength dental glass–ceramics. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 463–470, 2012.
Design of designs
Authors: Laue Reinhard , Nikolova‐Popova Daniela 
Published: November 2011

AbstractRepresenting a design graphically can make certain properties of a design obvious that otherwise would require tedious reasoning. This holds for symmetries, resolvability, and subdesign inclusion in appropriate cases. We describe how a graphical representation can be achieved in many cases and show several examples, in particular visualizations of the biplanes on up to 16 vertices and subdesigns of the large Witt design. © 2011 Wiley Periodicals, Inc. J Combin Designs 20:1–22, 2012
Vitamin C treatment promotes mesenchymal stem cell sheet formation and tissue regeneration by elevating telomerase activity
Authors: Wei Fulan , Qu Cunye , Song Tieli , Ding Gang , Fan Zhipeng , Liu Dayong , Liu Yi , Zhang Chunmei , Shi Songtao , Wang Songlin 
Published: November 2011

AbstractCell sheet engineering has been developed as an alternative approach to improve mesenchymal stem cell‐mediated tissue regeneration. In this study, we found that vitamin C (Vc) was capable of inducing telomerase activity in periodontal ligament stem cells (PDLSCs), leading to the up‐regulated expression of extracellular matrix type I collagen, fibronectin, and integrin β1, stem cell markers Oct4, Sox2, and Nanog as well as osteogenic markers RUNX2, ALP, OCN. Under Vc treatment, PDLSCs can form cell sheet structures because of increased cell matrix production. Interestingly, PDLSC sheets demonstrated a significant improvement in tissue regeneration compared with untreated control dissociated PDLSCs and offered an effective treatment for periodontal defects in a swine model. In addition, bone marrow mesenchymal stem cell sheets and umbilical cord mesenchymal stem cell sheets were also well constructed using this method. The development of Vc‐mediated mesenchymal stem cell sheets may provide an easy and practical approach for cell‐based tissue regeneration. J. Cell. Physiol. 227: 3216–3224, 2012. © 2011 Wiley Periodicals, Inc.
Depletion of GRIM‐19 accelerates hepatocellular carcinoma invasion via inducing EMT and loss of contact inhibition
Authors: Hao Hongbo , Liu Jun , Liu Guoliang , Guan Dongshi , Yang Yang , Zhang Xiuqing , Cao Xinmin , Liu Qian 
Published: November 2011

AbstractGenes associated with retinoid‐interferon‐induced mortality 19 (GRIM‐19) was identified as a tumor suppressor protein associated with apoptosis and growth inhibition. Here, we report that the expression levels of GRIM‐19 are significantly attenuated in hepatocellular carcinoma (HCC) patients with deteriorating differentiation states, hepatic capsule invasion and microvascular invasion, suggesting the potential role of GRIM‐19 not only at the origin but also in the invasive progression of HCCs. To dissect the possible mechanisms by which GRIM‐19 regulates tumor cell invasion, we established the hepatic HL‐7702 and HCC Huh‐7 cell lines stably depleted of GRIM‐19. Results show that downregulation of GRIM‐19 induces a morphological transformation resembling epithelial–mesenchymal transition (EMT) as well as aberrant expression of epithelial and mesenchymal molecular markers. Additionally, these cells lose contact inhibition, a phenomenon of cessation of cell migration in contact with neighboring cells, as assessed by cell imaging, growth curve and S‐phase transition in confluent conditions. Conclusion: Our observations demonstrate a novel mechanistic insight into a critical role of GRIM‐19 in HCC invasive potential. J. Cell. Physiol. 227: 1212–1219, 2012. © 2011 Wiley Periodicals, Inc.
Tetrahydropyridinium bromide: Useful synthon to functionalized pyrrolidines
Authors: Guideri Luca , Noschese Rossella , Ponticelli Fabio 
Published: November 2011

Abstract1‐benzyl‐5‐(ethoxycarbonyl)‐2,3,4,5‐tetrahydropyridinium bromide undergoes ring contraction with a series of nucleophiles, getting 2,2‐disubstitued pyrrolidines. Moreover, from some of the new 2,2‐disubstitued pyrrolidines were synthesized spiro‐pyrrolidines. J. Heterocyclic Chem.,(2011).