bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiation of methylbenzylpiperazines (MBPs) and benzoylpiperazine (BNZP) using GC‐MS and GC‐IRD
Authors: Abdel‐Hay Karim M. , DeRuiter Jack , Randall Clark C. 
Published: February 2012

Three‐ring substituted methylbenzylpiperazines (MBPs) and their isobaric benzoylpiperazine (BNZP) have equal mass and many common mass spectral fragment ions. The mass spectrum of BNZP yields a unique benzoyl‐group containing fragment at m/z 122 and an additional major fragment at m/z 69 that allows its discrimination from the three MBP regioisomers. Perfluoroacylation of the secondary amine nitrogen of these isomeric piperazines gave mass spectra with differences in relative abundance of some fragment ions but acylation does not alter the fragmentation pathway and did not provide additional MS fragments of discrimination among these isomers.Gas chromatography coupled with infrared detection (GC‐IRD) provides direct confirmatory data for the structural differentiation between the four isomers. The mass spectra in combination with the vapour phase IR spectra provide for specific confirmation of each of the isomeric piperazines. The underivatized and perfluoroacyl derivatives of these four piperazines were resolved on a stationary phase of 100% trifluoropropyl methyl polysiloxane (Rtx‐200). Gas chromatography coupled with time‐of‐flight mass spectrometry provides an additional means of differentiating between the isobaric MBP and BNZP which have equivalent nominal masses but are different in their elemental composition and exact masses. Copyright © 2012 John Wiley & Sons, Ltd.
A role for Drosophila Wnt‐4 in heart development
Authors: Tauc Helen M. , Mann Tabea , Werner Kathrin , Pandur Petra 
Published: February 2012

AbstractIn vertebrates, different Wnt‐signaling pathways are required in a temporally coordinated manner to promote cardiogenesis. In Drosophila, wingless holds an essential role in heart development. Among the known Drosophila Wnts is DWnt4, the function of which has been studied in various developmental processes except for heart development. We re‐evaluated the expression pattern of DWnt4 during embryogenesis and show that transcripts are not restricted to the dorsal ectoderm but are also present in the cardiogenic mesoderm. Moreover, we detect DWnt4 mRNA transcripts in myocardial cells by stage 16. The heart phenotype in DWnt4 mutant embryos is characterized by various degrees of disrupted expression of different cardiac markers. Overexpression of Dwnt4 also affects heart marker expression, which can be partially rescued by simultaneous inhibition of PKC. Our data reveal a role for DWnt4 in cardiogenesis; however, integration of DWnt4 with other known signaling pathways that function in heart development still awaits further investigation. genesis 50:466–481, 2012. © 2012 Wiley Periodicals, Inc.
Lanthanide Loaded Zeolites, Clays, and Mesoporous Silica Materials as MRI Probes
Authors: Peters Joop A. , Djanashvili Kristina 
Published: February 2012

AbstractZeolites, clays, and mesoporous silica materials offer the possibility to be loaded with Ln3+ ions either by means of ion exchange of the cations that are balancing the negative charge of the framework or by grafting of Ln3+ chelates to the framework. In this Microreview, the structures of the materials used up to now are described and related to their stabilities and relaxometric behavior. The possible exploitation of the unique features of these materials as both positive and negative MRI contrast agents in multimodal probes and in theranostics are discussed.
Synthesis of Enantiopure 7‐Substituted Azepane‐2‐carboxylic Acids as Templates for Conformationally Constrained Peptidomimetics
Authors: Cini Elena , Bifulco Giuseppe , Menchi Gloria , Rodriquez Manuela , Taddei Maurizio 
Published: February 2012

AbstractThe introduction of a cyclic amino acid in a peptide is one of the best methods to rigidify a strand. A general approach towards a new class of seven‐membered ring amino acids is described starting from (S)‐tribenzyl glutamic acid γ‐aldehyde, which reacts with β‐keto phosphonates to generate the Horner–Wadsworth–Emmons product. In the presence of H2 and a Pd catalyst, a four‐step process occurs involving double‐bond hydrogenation, hydrogenolysis of three benzyl protecting groups, imine formation, and reductive amination to produce the 7‐substituted azepane carboxylic acid in good overall yield and with good to excellent diastereomeric ratios. An amino function can be introduced in the 7‐position as an additional orthogonal chemical handle for readily generating diversity on the cyclic amino acid scaffold by using a β‐keto phosphonate derived from amino acids. A cyclic RGD (Arg‐Gly‐Asp) pentapeptide analogue containing this new class of noncoded amino acids was also prepared by microwave‐assisted cyclization, showing a promising activity as αvβ3 integrin inhibitor.
Basicity of Phosphanes and Diphosphanes in Acetonitrile
Authors: Haav Kristjan , Saame Jaan , Kütt Agnes , Leito Ivo 
Published: February 2012

AbstractPhosphanes are widely used in organic chemistry. Their basicity is important in determining their behavior in solutions of different acidity. We report a study of the basicities of various mono‐ and diphosphanes in acetonitrile, some of them of significant practical interest (BINAP, BIPHEP). The basicities of the studied phosphanes in acetonitrile are in the pKa range of 4–16. From the results, the relationship between the structure and basicity of the phosphanes has been analyzed and compared with that of amines of similar structure. A remarkably stronger change in basicity can be observed in the amines in comparison with the phosphanes when alkyl groups are replaced by aryl groups. This is mainly caused by resonance between the aryl group and the lone pair of the basicity center, which is strong in the case of the nitrogen atom and weak in the case of the phosphorus atom. The results of the basicity measurements of the diphosphanes in this work has led to two tentative conclusions: (1) there is no intramolecular hydrogen bond in protonated diphosphanes with an alkyl backbone, and (2) there may be a weak intramolecular hydrogen bond in protonated diphosphanes with an aromatic backbone.
Maximise lifetime of wireless sensor networks via a distributed cooperative routing algorithm
Authors: Zhai Chao , Liu Ju , Zheng Lina , Xu Hongji , Chen He 
Published: February 2012

ABSTRACTCombining cooperative diversity, truncated automatic repeat request scheme and distributed energy‐aware routing strategy, a novel cooperative routing algorithm adopting decode‐and‐forward fashion is proposed to maximise the lifetime of wireless sensor networks from the cross‐layer design perspective. In this algorithm, the transmission power is optimally allocated while satisfying the per‐link symbol error rate or the end‐to‐end throughput requirement. The average total consumed power weighted by the normalised remaining energy of every participating node is used as the link cost to avoid the overuse of certain nodes with extremely little energy. With the use of the traditional distributed shortest path algorithm, the best route that includes a cascade of single‐relay building blocks is constructed with polynomial complexity. In contrast to the non‐cooperative routing schemes, this cooperative routing algorithm can significantly prolong the network lifetime and improve the energy efficiency by reducing the total network residual energy. Copyright © 2012 John Wiley & Sons, Ltd.
Bee colony approach for advance resource reservation in optical based grids
Authors: Marković Goran , Radojičić Valentina 
Published: February 2012

ABSTRACTWe study the advance resource reservation (ARR) problem in multi‐wavelength optical‐based grids under the deterministic scheduled traffic demands. The bee colony optimization meta‐heuristic is used to solve the complex combinatorial ARR problem in which the objective is to maximize the number of established lightpaths. Simulation studies prove that the proposed bee colony optimization‐ARR algorithm is able to produce good approximate solutions within reasonable amount of computation time.Copyright © 2012 John Wiley & Sons, Ltd.
Fire behaviour and external flames in corridor and tunnel‐like enclosures
Authors: Beji T. , Ukleja S. , Zhang J. , Delichatsios M. A. 
Published: February 2012

ABSTRACTThis work investigates how the inflow, the burning and the outflow develop in a corridor open to one end having a fire at either the closed or open end. The situation of a corridor fire having a fire source at the close end is a situation similar to a tunnel having a fire source at the centre of the tunnel without ventilation. A gaseous propane burner is used to produce the fire at a prescribed fuel flow rate in a long corridor of aspect ratio up to 6:1 having a rectangular cross section and varying door‐like openings. Gas temperatures using thermocouple trees, heat fluxes in the corridor and on its façade, flame heights of emerging flames and total heat release rates (HRRs) are measured as the fuel flow rate of propane increases gradually and linearly with time to a preset maximum value. For over‐ventilated conditions, the flames remain near the fire source at the closed end of the corridor. Unexpectedly, it is established for under‐ventilated conditions that the inflow of air is not affected by the aspect ratio of the corridor or the location of the burner in the corridor and that the vertical distribution of gas temperatures inside the enclosure is nearly uniform with height everywhere. In addition, the flame heights and heat fluxes on the façade are the same as those for aspect ratios of the corridor from 1:1 to 3:1 examined in previous work. Moreover, as the conditions changed from over‐ventilated to under‐ventilated conditions, the flames migrated in a ghostly manner from the closed end to the open end of the corridor as soon as under‐ventilated conditions were established. The speed of migration of the flames from the back to the front has also been inferred from the thermocouple tree measurements, which also indicate that the flow conditions ahead and after the passing of the front are changed. These results can be applied to interpret some of the observed behaviours of fires in long corridors or tunnels without ventilation. Copyright © 2012 John Wiley & Sons, Ltd.
Glutathione peroxidase tagSNPs: Associations with rectal cancer but not with colon cancer
Authors: Haug Ulrike , Poole Elizabeth M. , Xiao Liren , Curtin Karen , Duggan David , Hsu Li , Makar Karen W. , Peters Ulrike , Kulmacz Richard J. , Potter John D. , Koepl Lisel , Caan Bette J. , Slattery Martha L. , Ulrich Cornelia M. 
Published: February 2012

AbstractGlutathione peroxidases (GPXs) are selenium‐dependent enzymes that reduce and, thus, detoxify hydrogen peroxide and a wide variety of lipid hydroperoxides. We investigated tagSNPs in GPX1‐4 in relation to colorectal neoplasia in three independent study populations capturing the range of colorectal carcinogenesis from adenoma to cancer. A linkage‐disequilibrium (LD)‐based tagSNP selection algorithm (r2 ≥ 0.90, MAF ≥ 4%) identified 21 tagSNPs. We used an identical Illumina platform to genotype GPX SNPs in three population‐based case–control studies of colon cancer (1,424 cases/1,780 controls), rectal cancer (583 cases/775 controls), and colorectal adenomas (485 cases/578 controls). For gene‐level associations, we conducted principal component analysis (PCA); multiple logistic regression was used for single SNPs. Analyses were adjusted for age, sex, and study center and restricted to non‐Hispanic white participants. Analyses of cancer endpoints were stratified by molecular subtypes. Without correction for multiple testing, one polymorphism in GPX2 and three polymorphisms in GPX3 were associated with a significant risk reduction for rectal cancer at α = 0.05, specifically for rectal cancers with TP53 mutations. The associations regarding the three polymorphisms in GPX3 remained statistically significant after adjustment for multiple comparisons. The PCA confirmed an overall association of GPX3 with rectal cancer (P = 0.03). No other statistically significant associations were observed. Our data provide preliminary evidence that genetic variability in GPX3 contributes to risk of rectal cancer but not of colon cancer and thus provide additional support for differences in underlying pathogenetic mechanisms for colon and rectal cancer. © 2012 Wiley Periodicals, Inc.
Delineation of commonly deleted chromosomal regions in meningiomas by high‐density single nucleotide polymorphism genotyping arrays
Authors: Tabernero Maria Dolores , Maíllo Angel , Nieto Ana Belen , Diez‐Tascón Cristina , Lara Mónica , Sousa Pablo , Otero Alvaro , Castrillo Abel , Patino‐Alonso Maria del Carmen , Espinosa Ana , Mackintosh Carlos , Alava Enrique de , Orfao Alberto 
Published: February 2012

AbstractDespite recent advances in the identification of the cytogenetic profiles of meningiomas, a significant group of tumors still show normal karyotypes or few chromosomal changes. The authors analyzed the cytogenetic profile of 50 meningiomas using fluorescence in situ hybridization and high‐density (500 K) single nucleotide polymorphism (SNP) arrays. Our results confirm that del(22q) (52%) and del(1p) (16%) (common deleted regions: 22q11.21‐22q13.3. and 1p31.2‐p36.33) are the most frequent alterations. Additionally, recurrent monosomy 14 (8%), del(6q) (10%), del(7p) (10%), and del(19q) (4%) were observed, while copy number patterns consistent with recurrent chromosomal gains, gene amplification, and copy number neutral loss of heterozygosity (cnLOH) were either absent or rare. Based on their overall SNP profiles, meningiomas could be classified into: (i) diploid cases, (ii) meningiomas with a single chromosomal change [e.g., monosomy 22/del(22q)] and (iii) tumors with ≥2 altered chromosomes. In summary, our results confirm and extend on previous observations showing that the most recurrent chromosomal abnormalities in meningiomas correspond to chromosome losses localized in chromosomes 1, 22 and less frequently in chromosomes 6, 7, 14, and 19, while chromosomal gains and cnLOH are restricted to a small proportion of cases. Finally, a set of cancer‐associated candidate genes associated with the TP53, MYC, CASP3, HDAC1, and TERT signaling pathways was identified, in cases with coexisting monosomy 14 and del(1p). © 2012 Wiley Periodicals, Inc.
Isolation and characterization of living primary astroglial cells using the new GLAST‐specific monoclonal antibody ACSA‐1
Authors: Jungblut Melanie , Tiveron Marie Catherine , Barral Serena , Abrahamsen Bjarke , Knöbel Sebastian , Pennartz Sandra , Schmitz Jürgen , Perraut Martine , Pfrieger Frank W. , Stoffel Wilhelm , Cremer Harold , Bosio Andreas 
Published: February 2012

AbstractAstrocytes show large morphological and functional heterogeneity and are involved in many aspects of neural function. Progress in defining astrocyte subpopulations has been hampered by the lack of a suitable antibody for their direct detection and isolation. Here, we describe a new monoclonal antibody, ACSA‐1, which was generated by immunization of GLAST1 knockout mice. The antibody specifically detects an extracellular epitope of the astrocyte‐specific L‐glutamate/L‐aspartate transporter GLAST (EAAT1, Slc1a3). As shown by immunohistochemistry, immunocytochemistry, and flow cytometry, ACSA‐1 was cross‐reactive for mouse, human, and rat. It labeled virtually all astrocytes positive for GFAP, GS, BLBP, RC2, and Nestin, including protoplastic, fibrous, and reactive astrocytes as well as Bergmann glia, Müller glia, and radial glia. Oligodendrocytes, microglia, neurons, and neuronal progenitors were negative for ACSA‐1. Using an immunomagnetic approach, we established a method for the isolation of GLAST‐positive cells with high purity. Binding of the antibody to GLAST and subsequent sorting of GLAST‐positive cells neither interfered with cellular glutamate transport nor compromised astrocyte viability in vitro. The ACSA‐1 antibody is not only a valuable tool to identify and track astrocytes by immunostaining, but also provides the possibility of separation and further analysis of pure astrocytes. © 2012 Wiley Periodicals, Inc.
Paclitaxel and iron oxide loaded multifunctional nanoparticles for chemotherapy, fluorescence properties, and magnetic resonance imaging
Authors: Chen Yung‐Chu , Lee Wen‐Fu , Tsai Han‐Hsueh , Hsieh Wen‐Yuan 
Published: February 2012

AbstractThe multifunctional nanoparticles constructed from triphenylamine‐poly(lactide‐co‐glycolide)‐poly(ethyleneglycol)‐poly(lactide‐co‐glycolide) (TPA‐PEP) and folate‐poly(2‐ethyl‐2oxazoline)‐poly(D,L‐lactide) (folate‐PEOz‐PLA) were developed in this study. Iron oxide nanoparticles (IOP) and paclitaxel (PTX) were coencapsulated in the nanoparticles with diameter less than 200 nm. The drug‐loaded nanoparticles emit fluorescence peak at 460 nm when excited with wavelength of 350 nm. The in vitro antitumor activity of the drug‐loaded nanoparticles was assessed by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays against HeLa cells. When the cells were exposed to the nanoparticles with different levels of folate but the same drug loading, cell viability decreases as the level of folate increases. Confocal laser scanning microscopy (CLSM) analysis shows that cellular uptake is lower for the non‐folate–nanoparticles than that for the folate–nanoparticles. The in vitro and in vivo magnetic resonance imaging (MRI) studies indicate the better T2‐Weighted images can be obtained for the folate–nanoparticles. In the anticancer effect evaluation, tumor‐bearing mice administered with the 30%‐folate‐nanoparticles showed ∼50% reduction in tumor volume after 23 days. The multifunctional nanoparticles as drug carrier with capabilities of both tumor‐targeting and MRI present a new direction in drug delivery system development. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
Preparation andin vitrocharacterization of electrospun PVA scaffolds coated with bioactive glass for bone regeneration
Authors: Gao Chunxia , Gao Qiang , Li Yadong , Rahaman Mohamed N. , Teramoto Akira , Abe Koji 
Published: February 2012

AbstractAn important objective in bone tissue engineering is to fabricate biomimetic three‐dimensional scaffolds that stimulate mineralization for rapid regeneration of bone. In this work, scaffolds of electrospun poly(vinyl alcohol) (PVA) fibers (diameter = 286 ± 14 nm) were coated with a sol–gel derived bioactive glass (BG) and evaluatedin vitrofor potential applications in bone repair. Structural and chemical analyses showed that the BG coating was homogeneously deposited on the PVA fibers.In vitrocell culture studies showed that the BG‐coated PVA scaffold had a greater capacity to support proliferation of osteogenic MC3T3‐E1 cells, alkaline phosphatase activity, and mineralization than the uncoated PVA scaffold. The BG coating improved the tensile strength of the PVA scaffold from 18 ± 2 MPa to 21 ± 2 MPa, but reduced the elongation to failure from 94 ± 4% to 64 ± 5%. However, immersion of the BG‐coated PVA scaffolds in a simulated body fluid for 5 days resulted in an increase in the tensile strength (24 ± 2 MPa) and elongation to failure (159 ± 4%). Together, the results show that these BG‐coated PVA scaffolds could be considered as candidate materials for bone tissue engineering applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
Enzymatically induced mineralization of platelet‐rich fibrin
Authors: Douglas Timothy E. L. , Gassling Volker , Declercq Heidi A. , Purcz Nicolai , Pamula Elzbieta , Haugen Håvard J. , Chasan Safak , de Mulder Eric L. W. , Jansen John A. , Leeuwenburgh Sander C. G. 
Published: February 2012

AbstractMembranes of the autologous blood‐derived biomaterial platelet‐rich fibrin (PRF) were functionalized by incorporation of alkaline phosphatase (ALP), an enzyme involved in mineralization of bone, and subsequently incubated in calcium glycerophosphate (CaGP) solution to induce PRFs mineralization with calcium phosphate (CaP) to improve PRFs suitability as a material for bone replacement. Incorporated ALP retained its bioactivity and induced formation of CaP material within PRF membranes, as confirmed by SEM, EDS, FTIR, and von Kossa staining. The mass percentage attributable to CaP was quantified by lyophilization and measurement of the remaining mass fraction as well as by TGA. Cytocompatibility tests (LDH, MTT, and WST) with SAOS‐2 cells showed that mineralized PRF did not release substances detrimental to cell vitality. Live/dead staining and SEM showed that mineralized PRF was colonized by cells. The results show that hydrogel biomaterials such as PRF can be mineralized through functionalization with ALP. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
Endothelialization and in‐stent restenosis on the surface of glycoprotein IIIa monoclonal antibody eluting stent
Authors: Yin Tie‐Ying , Wang Gui‐Xue , Zhang De‐Chuan , Du Ding‐Yuan , Li Zheng‐Gong , Luo Lai‐Long , Hou Yan‐Bin , Wang Ya‐Zhou , Zhao Jing‐Bo 
Published: February 2012

AbstractSince the percutaneous transtuminal coronary angioplasty was introduced into China in 1984, this procedure has become widely accepted as an important step in coronary revascularization. This study shows the effect of the monoclonal antibody (mAb) on the platelet glycoprotein IIIa receptor during endothelialization and in‐stent restenosis by implanting the mAb‐eluting stents into iliac arteries of rabbits. The hard tissue cross sections of the stent‐implanted arterial segments were made by polymethylmethacrylate embedding. Arterial intima proliferation was observed and analyzed. The endothelialization of the stent surface was observed using scanning electron microscope, whereas the ultrastructure of the neointima was observed using transmission electron microscope. After one month of stent implantation, the surfaces of both groups were covered by intact endothelial layers, but the neointimal areas and the ratio of stenosis were significantly lesser in the mAb‐eluting stent group (p < 0.01). After 3 months, the ratio of stenosis in the mAb‐eluting stent group was 14.67 ± 0.79, whereas that of the bare stent group was 21.58 ± 1.76 (p < 0.01). Therefore, the mAb eluting from the stent surface has the potential to accelerate endothelialization, prevent thrombosis formation due to the interaction of stent with blood, and decrease the stenosis ratio by inhibiting neointima proliferation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.