bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uniform Chitosan Microspheres for Potential Application to Colon‐Specific Drug Delivery
Authors: Choy Young Bin , Cheng Felice , Choi Hyungsoo , Kim Kyekyoon (Kevin) 
Published: August 2008

AbstractUniform chitosan microspheres have been fabricated and weakly crosslinked for potential applications in colon‐specific drug delivery. The effects of microsphere size, crosslinking density and electrostatic interactions between the drug and chitosan on drug release were studied, employing model drugs of different acidities. When the drug was basic, all chitosan spheres exhibited 100% release within 30 min. As the acidity of the drug increased, the release slowed down and depended on the crosslinking density and microsphere size. The release of weakly acidic drug was most suppressed for large spheres (35–38 µm), while the small spheres (23–25 µm) with higher crosslinking exhibited the most retention of highly acidic drug, indicating that they are a promising candidate for colon‐specific delivery.magnified image
Localized Yielding Around Crack Tips of Double‐Network Gels
Authors: Tanaka Yoshimi , Kawauchi Yasunori , Kurokawa Takayuki , Furukawa Hidemitsu , Okajima Takaharu , Gong Jian Ping 
Published: August 2008

AbstractDouble‐network (DN) gels, a type of interpenetrating polymer network (IPN) consisting of rigid and flexible polymer components, exhibit two outstanding mechanical behaviors: yielding deformation of the entire specimen in tensile tests and quite high fracture energy in tearing tests. In this study, atomic force microscope (AFM) measurements were conducted on DN gels to determine the local Young's moduli immediately below the fracture surfaces Ef and below the usual molded surfaces Em, and compare the local modulus with bulk Young's moduli measured before and after the yielding deformation, denoted as Eh and Es, respectively. Em and Eh are around 0.1 MPa; Ef and Es, around 0.01 MPa, one order lower than the former two moduli. The order relation indicates that yielding deformation occurred locally around the crack tip of the DN gel during fracture. This supports the basic assumption of phenomenological models recently proposed to explain high fracture energy of DN gels. (H. R. Brown, Macromolecules 2007, 40, 3815–3818; Y. Tanaka, Europhys. Lett. 2007, 78, 56005).magnified image
Reversible and Highly Selective Fluorescent Sensor for Mercury(II) Based on a Water‐Soluble Poly(para‐phenylene)s Containing Thymine and Sulfonate Moieties
Authors: Lv Jing , Ouyang Canbin , Yin Xiaodong , Zheng Haiyan , Zuo Zicheng , Xu Jialiang , Liu Huibiao , Li Yuliang 
Published: August 2008

AbstractA novel water‐soluble poly(para‐phenylene) derivative with pendant thymine and sulfonate units (PBTS) has been prepared and its metal ion sensing properties have been investigated. PBTS exhibited a reversible and selective fluorescence quenching behavior toward Hg2+ ions as compared to Ag+, Ni2+, Mg2+, Ca2+, Hg2+, Co2+, Cd2+, Cu2+, Pb2+, Ba2+, Fe3+, and Zn2+ ions in aqueous solution. The fluorescence quenching resulted from the interpolymeric π‐stacking aggregation which was induced by the specific thymine–Hg–thymine interaction.magnified image
Functionalization of Multi‐Walled Carbon Nanotubes by Thermo‐Grafting with α‐Methylstyrene‐Containing Copolymers
Authors: Jiang Shan , Deng Jianping , Yang Wantai 
Published: August 2008

AbstractThe present article reports on a strategy for the functionalization of multi‐walled carbon nanotubes (MWCNTs) by grafting with various polymer chains. Copolymers consisting of α‐methylstyrene (AMS) and a second monomer, that is glycidyl methacrylate (GMA) or styrene (St), were synthesized in advance. The copolymers were heated in the presence of MWCNTs in solution, decomposition of the AMS sequences occurred, providing macroradicals, which further attacked the double bonds on the MWCNT surfaces. Grafting of the copolymer chains onto the surface of the MWCNTs was thus achieved, as demonstrated by FT‐IR, XPS and Raman technologies. The resulting poly(AMS‐co‐GMA)‐g‐MWCNTs could be uniformly dispersed in N,N‐dimethylformamide (DMF) and acetone, and the poly(AMS‐co‐St)‐g‐MWCNTs also could be uniformly dispersed in DMF.magnified image
Parameterization of tropospheric delay correction for mobile GNSS positioning: a case study of a cold front passage
Authors: Eresmaa R. , Nordman M. , Poutanen M. , Syrjärinne J. , Luntama J. ‐ P. , Järvinen H. 
Published: August 2008

AbstractNumerical weather prediction (NWP) model output can be used for derivation of tropospheric delay correction in order to decrease positioning errors of Global Navigation Satellite System (GNSS) applications. In precise geodetic positioning it is possible to make use of corrections that are derived separately for all GNSS signal paths. Due to the large amounts of data, this approach is considered impractical from real‐time mobile positioning point of view. This article introduces several parameterization schemes that provide a zenith‐ and azimuth‐angle‐dependent description of tropospheric delay correction at a single observation site. These parameterization schemes are compared in a case study of a cold front passage. Inclusion of zenith‐angle dependency in the parameterization, instead of applying a prescribed mapping function, is found to be crucially important for accuracy. Parameterization can be further improved by applying a horizontal delay gradient and by separating the total tropospheric delay into hydrostatic and wet components. It is concluded that any increase of sophistication in the parameterization results in an increased parameterization accuracy. Copyright © 2008 Royal Meteorological Society
Mechanisms and sequelae of E‐cadherin silencing in hereditary diffuse gastric cancer
Authors: Barber M , Murrell A , Ito Y , Maia A‐T , Hyland S , Oliveira C , Save V , Carneiro F , Paterson AL , Grehan N , Dwerryhouse S , Lao‐Sirieix P , Caldas C , Fitzgerald RC 
Published: August 2008

AbstractAround 25–40% of cases of hereditary diffuse gastric cancer (HDGC) are caused by heterozygous E‐cadherin (CDH1) germline mutations. The mechanisms for loss of the second allele still remain unclear. The aims of this study were to elucidate mechanisms for somatic inactivation of the wild‐type CDH1 allele and to seek evidence for cadherin switching. Archival tumour material was analysed from 16 patients with CDH1 germline mutations and seven patients fulfilling HDGC criteria without CDH1 germline mutations. The 16 CDH1 exons were sequenced. E‐cadherin promoter methylation was analysed by bisulphite sequencing and pyrosequencing and allele specificity was determined using polymorphic loci. Loss of heterozygosity was analysed using microsatellite markers. Cadherin expression levels were determined by real‐time RT–PCR and immunohistochemistry. Six of 16 individuals with germline mutations had at least one second hit mechanism. Two exonic mutations (exon 9 truncating, exon 3 missense) and four intronic mutations which may affect splicing were identified. Tumours from 4/16 individuals had promoter hypermethylation that was restricted to the A allele haplotype in three cases. E‐cadherin loss (mRNA and protein) generally correlated with identification of a second hit. In cases without germline E‐cadherin mutations there was no evidence for somatic mutation or significant promoter methylation. P‐cadherin (>25% cells) was expressed in 7/13 (54%) and 4/5 (80%) with and without germline CDH1 mutations, respectively, independent of complete E‐cadherin loss. Overall, inactivation of the second CDH1 allele occurs by mutation and methylation events. Methylation is commonly allele‐specific and is uncommon without germline mutations. P‐cadherin over‐expression commonly occurs in individuals with diffuse type gastric cancer. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Comparative expression of Hedgehog ligands at different stages of prostate carcinoma progression
Authors: Azoulay S , Terry S , Chimingqi M , Sirab N , Faucon H , Diez de Medina S Gil , Moutereau S , Maillé P , Soyeux P , Abbou C , Salomon L , Vacherot F , de La Taille A , Loric S , Allory Y 
Published: August 2008

AbstractRecent studies have revealed the potential involvement of Hedgehog (Hh) signalling in proliferation and invasive behaviour of prostate carcinoma (PCa). The aim of this study was to specify the role of Sonic Hh (Shh), Desert Hh (Dhh) and Indian Hh (Ihh) in the natural history of PCa. Hh ligands expression was compared in primary hormone‐naive PCa (HNPC), hormone‐treated PCa (HTPC) and hormone‐refractory PCa (HRPC), using immunohistochemistry. Shh and Dhh were expressed by both epithelial and stromal cells of prostate tissues. Ihh was only expressed by stromal cells. For the three ligands, mRNA and immunostaining were not correlated. In HNPC, Shh epithelial expression was significantly associated with high Gleason scores (p = 0.03), metastatic lymph nodes (p = 0.004) and Dhh epithelial staining was associated with high pT stages (p = 0.003), seminal vesicle invasion (p = 0.03) and bladder neck invasion (p = 0.0008). Negative Shh staining in stromal cells was associated with high Gleason scores (p = 0.015), high pT stages (p = 0.01) and bladder neck invasion (p = 0.04). Concomitant absence of Shh and Dhh expression in stromal cells was an independent prognostic parameter for biological recurrence on multivariate analysis (p = 0.01). Epithelial expression of Shh and Dhh was increased in HTPC compared to HNPC (p = 0.02 and p = 0.04). Interestingly, in vitro, transcript analysis also showed increased expression of these 2 Hh ligands when androgen‐sensitive LNCaP cells were maintained in androgen‐free medium mimicking hormonal therapy. Epithelial expression of Dhh was increased (p < 0.0001) in HRPC compared to HNPC, while stromal expression of Shh and Dhh was decreased (p < 0.0001). In conclusion, the Hh signalling pathway is associated with pejorative pathological parameters in HNPC and is up‐regulated in epithelial cells of HTPC and HRPC. Moreover, the lack of Hh molecules in stromal cells seems to be associated with invasive and hormone‐refractory behaviours and suggests specific changes in stromal–epithelial crosstalks during PCa progression. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A critical role for TRAIL in resolution of granulomatous experimental autoimmune thyroiditis
Authors: Fang Y , Sharp GC , Yagita H , Braley‐Mullen H 
Published: August 2008

AbstractGranulomatous experimental autoimmune thyroiditis (G‐EAT) is induced by mouse thyroglobulin (MTG)‐sensitized splenocytes activated in vitro with MTG and IL‐12. Thyroid lesions reach maximal severity 20 days after cell transfer, and usually resolve or progress to fibrosis by day 60 depending on the extent of thyroid damage at day 20. Our previous studies indicated that neutralization of TNF‐α or FasL had no effect on G‐EAT induction, but neutralization of TNF‐α promoted, while neutralization of FasL inhibited, G‐EAT resolution. TNF‐related apoptosis‐inducing ligand (TRAIL) is a member of the TNF superfamily. This study was undertaken to define the role of endogenous TRAIL in G‐EAT development and/or resolution. Neutralization of endogenous TRAIL had little effect on G‐EAT induction, but significantly inhibited G‐EAT resolution and increased thyroid fibrosis. This correlated with higher expression of pro‐inflammatory cytokines and preferential expression of the pro‐apoptotic molecule TRAIL, and anti‐apoptotic molecules FLIP and Bcl‐xL on inflammatory cells in thyroids of anti‐TRAIL‐treated recipients. The results suggest that endogenous TRAIL is not required for G‐EAT development in recipients, but is critical for G‐EAT resolution. Endogenous TRAIL might promote resolution, at least in part, through modulation of the balance between pro‐ and anti‐inflammatory cytokines, and the expression pattern of pro‐ and anti‐apoptotic molecules of thyroid epithelial cells (TECs) and inflammatory cells. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Silica‐filled polypropylene composites: The effect of ethylene diamine dilaurate and maleic anhydride grafted polypropylene on mechanical properties, water absorption, morphology, and thermal properties
Authors: Suryadiansyah  , Ismail H. , Azhari B. 
Published: August 2008

AbstractThe effect of two compatibilizers, i.e. ethylene diamine dilaurate (EDD) and maleic anhydride grafted polypropylene (MAPP) on the mechanical properties, water absorption, morphology, and thermal properties of silica‐filled polypropylene (PP/Sil) composites were studied. The results show that the tensile, impact and flexural strengths (up to 2 php), Young's modulus, and elongation at break (Eb) increased with increasing EDD content. However, increasing MAPP content increases the tensile strength, Young's modulus, impact and flexural strengths, and water absorption resistance. At a similar compatibilizer content, EDD exhibits higher Eb, impact and flexural strengths but lowers tensile strength, Young's modulus, and water absorption resistance compared with MAPP. Scanning electron microscopy study of tensile fractured surfaces exhibits the evidence of better silica‐PP adhesion with MAPP and EDD compared with the similar composites but without compatibilizer. Fourier transform infra red spectra provide an evidence of interaction between EDD or MAPP with PP/Sil composites. Termogravimetry analysis results indicate that the addition of EDD or MAPP slightly increases the thermal stability of PP/Sil composites. Differential scanning calorimetry also indicates that PP/Sil composites with EDD or MAPP have higher heat fusion (ΔHf(com)) and crystallinity (Xcom) than similar composites but without compatibilizer. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Crystallization behavior and mechanical properties of polypropylene/modified carbon black composites
Authors: Zhu Ping , Chen Jing , Wu Chifei 
Published: August 2008

AbstractCarbon black (CB) modified with small organic molecules was filled in polypropylene (PP) matrix. The crystallization behavior and mechanical properties of PP/modified CB (MCB) composites were investigated. Compared with the original CB, MCB could be dispersed uniformly in smaller particle sizes in PP matrix, and MCB could act as a more effective nucleating, toughening, and reinforcing agent when it was filled in PP at low concentrations. Further increasing of MCB particles in PP matrix resulted in the decrease of impact and tensile strength of PP/MCB composites. It was inferred from DSC results that the existence of CB vand MCB in PP matrix could result in the decrease of crystallite size and degree of perfection of PP. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Preparation and microwave characterization of PTFE/PEEK blends
Authors: Rajani K.V. , Rajesh S. , Murali K.P. , Mohanan P. , Ratheesh R. 
Published: August 2008

AbstractPresent paper describes the preparation and characterization of the PTFE / PEEK blends. The surface morphology of different volume percentage of PTFE/PEEK blends is investigated using Scanning Electron Microscopy. The permittivity and loss tangent of the blends up to 40 MHz are studied using a Precision Impedance Analyzer. The variation of permittivity with respect to temperature (τεr) of the composite blends are also measured in the 0–100°C temperature region using a microprocessor controlled hot and cold chamber. The microwave dielectric properties of the polymer blends are studied in the X‐band (8.2–12.4 GHz) region by waveguide cavity perturbation technique using a Vector Network Analyzer. Rectangular cavity resonator is used to measure the complex permittivity of the PTFE/PEEK blends. Different modeling approaches are used to predict the theoretical permittivity of the blends and the results are compared with the experimental values. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Tensile properties of LDPE + Boehmite composites
Authors: Brostow Witold , Datashvili Tea , Huang Bernard , Too Jonathan 
Published: August 2008

AbstractEffect of interfacial interactions on mechanical properties of composites of low‐density polyethylene reinforced with micrometric Boehmite powders were studied in combination with two silane coupling agents vinyltri(2‐methoxyethoxy)‐silane (VTMES)‐SCA 972 and 3‐(trimethoxysilyl)‐propylmethacrylate (3MPS)‐SCA 989. Samples were prepared via melt mixing followed by compression or injection molding. Morphology and mechanical behavior of the composites were investigated as a function of the filler loading. The modulus of the composites increases with increasing contents of micrometric Boehmite particles. Environmental scanning electron microscopy (ESEM) examination reveals formation of fibrous structures upon addition of the treated micro fillers. We presume the fibrillation of the LDPE phase is related to changes of the matrix viscosity. Improvements in mechanical properties are attributed to homogeneous dispersion and good interfacial adhesion between the filler and the matrix, as evidenced by ESEM. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Flow cytometry‐assisted purification and proteomic analysis of the corticotropes dense‐core secretory granules
Authors: Gauthier Daniel J. , Sobota Jacqueline A. , Ferraro Francesco , Mains Richard E. , Lazure Claude 
Published: August 2008

AbstractThe field of organellar proteomics has emerged as an attempt to minimize the complexity of the proteomics data obtained from whole cell and tissue extracts while maximizing the resolution on the protein composition of a single subcellular compartment. Standard methods involve lengthy density‐based gradient and/or immunoaffinity purification steps followed by extraction, 1‐DE or 2‐DE, gel staining, in‐gel tryptic digestion, and protein identification by MS. In this paper, we present an alternate approach to purify subcellular organelles containing a fluorescent reporter molecule. The gel‐free procedure involves fluorescence‐assisted sorting of the secretory granules followed by gentle extraction in a buffer compatible with tryptic digestion and MS. Once the subcellular organelle labeled, this procedure can be done in a single day, requires no major modification to any instrumentation and can be readily adapted to the study of other organelles. When applied to corticotrope secretory granules, it led to a much enriched granular fraction from which numerous proteins could be identified through MS.
Laser desorption 7.87 eV postionization mass spectrometry of antibiotics in Staphylococcus epidermidis bacterial biofilms
Authors: Gasper Gerald L. , Carlson Ross , Akhmetov Artem , Moore Jerry F. , Hanley Luke 
Published: August 2008

AbstractThis paper describes the development of laser desorption 7.87 eV vacuum UV (VUV) postionization MS to detect antibiotics within intact bacterial colony biofilms. As >99% of the molecules ejected by laser desorption are neutrals, VUV photoionization of these neutrals can provide significantly increased signal as compared to the detection of directly emitted ions. Postionization with VUV radiation from the molecular fluorine laser single photon ionizes laser desorbed neutrals with ionization potentials below the 7.87 eV photon energy. Antibiotics with structures indicative of sub‐7.87 eV ionization potentials were examined for their ability to be detected by 7.87 eV laser desorption postionization MS. Tetracycline, sulfadiazine, and novobiocin were successfully detected neat as dried films physisorbed on porous silicon oxide substrates. Tetracycline and sulfadiazine were then detected within intact Staphylococcus epidermidis colony biofilms, the former with LOD in the micromolar concentration range.
Molecular dynamics guided study of salt bridge length dependence in both fluorinated and non‐fluorinated parallel dimeric coiled‐coils
Authors: Pendley Scott S. , Yu Yihua B. , Cheatham Thomas E. 
Published: August 2008

AbstractThe α‐helical coiled‐coil is one of the most common oligomerization motifs found in both native and engineered proteins. To better understand the stability and dynamics of the coiled‐coil motifs, including those modified by fluorination, several fluorinated and nonfluorinated parallel dimeric coiled‐coil protein structures were designed and modeled. We also attempt to investigate how changing the length and geometry of the important stabilizing salt bridges influences the coiled‐coil protein structure. Molecular dynamics (MD) and free energy simulations with AMBER used a particle mesh Ewald treatment of the electrostatics in explicit TIP3P solvent with balanced force field treatments. Preliminary studies with legacy force fields (ff94, ff96, and ff99) show a profound instability of the coiled‐coil structures in short MD simulation. Significantly, better behavior is evident with the more balanced ff99SB and ff03 protein force fields. Overall, the results suggest that the coiled‐coil structures can readily accommodate the larger acidic arginine or S‐2,7‐diaminoheptanedoic acid mutants in the salt bridge, whereas substitution of the smallerL‐ornithine residue leads to rapid disruption of the coiled‐coil structure on the MD simulation time scale. This structural distortion of the secondary structure allows both the formation of large hydration pockets proximal to the charged groups and within the hydrophobic core. Moreover, the increased structural fluctuations and movement lead to a decrease in the water occupancy lifetimes in the hydration pockets. In contrast, analysis of the hydration in the stable dimeric coiled‐coils shows high occupancy water sites along the backbone residues with no water occupancy in the hydrophobic core, although transitory water interactions with the salt bridge residues are evident. The simulations of the fluorinated coiled‐coils suggest that in some cases fluorination electrostatically stabilizes the intermolecular coiled‐coil salt bridges. Structural analyses also reveal different side chain rotamer preferences for leucine when compared with 5,5,5,5′,5′,5′‐hexafluoroleucine mutants. These observed differences in the side chain rotamer populations suggest differential changes in the side chain conformational entropy upon coiled‐coil formation when the protein is fluorinated. The free energy of hydration of the isolated 5,5,5,5′,5′,5′‐hexafluoroleucine amino acid is calculated to be 1.1 kcal/mol less stable than leucine; this hydrophobic penalty in the monomer may provide a driving force for coiled‐coil dimer formation. Estimation of the ellipticity at 222 nm from a series of snapshots from the MD simulations with DicroCalc shows distinct increases in the ellipticity when the coiled‐coil is fluorinated, which suggests that the helicity in the folded coiled‐coils is greater when fluorinated. Proteins 2009. © 2008 Wiley‐Liss, Inc.