bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporation of growth factor containing Matrigel promotes vascularization of porous PLGA scaffolds
Authors: Laschke M. W. , Rücker M. , Jensen G. , Carvalho C. , Mülhaupt R. , Gellrich N.‐C. , Menger M. D.
Published: August 2007

In tissue engineering, rapid ingrowth of blood vessels into scaffolds is a major prerequisite for the survival of three‐dimensional tissue constructs. In the present study, we investigated whether the vascularization of implanted poly‐D,L‐lactic‐co‐glycolic acid (PLGA) scaffolds may be accelerated by incorporation of Matrigel. For this purpose, we investigated in the aortic ring assay the proangiogenic properties of growth factor reduced Matrigel (GFRM) and growth factor containing Matrigel (GFCM), which were then incorporated into the pores of PLGA scaffolds. Subsequently, we analyzed vascularization, biocompatibility, and incorporation of these scaffolds during 14 days after implantation into dorsal skinfold chambers of balb/c mice by means of intravital microscopy, histology, and immunohistochemistry. Matrigel‐free scaffolds served as controls. In the aortic ring assay, GFCM stimulated the development of a network of tubular vessel structures with a significantly increased sprout area and density when compared with GFRM. Accordingly, GFCM accelerated and improved in vivo the ingrowth of new blood vessels into scaffolds, resulting in the formation of a pericyte‐coated vascular network with an increased functional capillary density in comparison to the GFRM and control group. Besides, analysis of leukocyte–endothelial cell interaction in host tissue venules located in close vicinity to the scaffolds showed no marked differences in numbers of rolling and adherent leukocytes between the observation groups, indicating that incorporation of Matrigel did not affect biocompatibility of PLGA scaffolds. These findings demonstrate that the combination of proangiogenic extracellular matrices with solid scaffold biomaterials may represent a novel approach to accelerate adequate vascularization of tissue engineering constructs. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Cellular compatibility of bone‐like apatite containing silicon species
Authors: Obata Akiko , Kasuga Toshihiro
Published: August 2007

A calcium carbonate/siloxane‐containing poly‐(lactic acid) composite (Si‐CCPC) was prepared by a sol‐gel method. Si‐CCPC was immersed in simulated body fluid for 3 days, resulting in the formation of bone‐like hydroxyapatite layer containing silicon species (b‐HA(Si)) on Si‐CCPC. The b‐HA(Si) was estimated in the cellular compatibility by culture tests using osteoblast‐like cells (MC3T3‐E1 cells), human mesenchymal stem cells (MSCs) and human osteoblasts (HOBs). Cellular number of MC3T3‐E1 cells and alkaline phosphatase activity of MSCs on the b‐HA(Si) increased significantly more in comparison with that on the conventional b‐HA (without silicon species). Cellular spreading of MC3T3‐E1 cells after 1 day of culturing was enhanced on the layer with and without silicon species. The b‐HA(Si) was expected to enhance cellular proliferation and osteogenic differentiation, and the b‐HA layer was believed to play the important role for cellular spreading. After 14 and 21 days of HOBs‐culturing, bone nodules formation was observed on the b‐HA(Si). The b‐HA(Si) has great potential in use as scaffolds for bone tissue engineering © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Scaffold permeability as a means to determine fiber diameter and pore size of electrospun fibrinogen
Authors: Sell Scott , Barnes Catherine , Simpson David , Bowlin Gary
Published: August 2007

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber diameter and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150 mg/mL) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were first analyzed with scanning electron microscopy and image analysis software. The permeability of each scaffold was measured with the flowmeter and used to calculate permeability‐based fiber diameters and pore sizes, which were compared to values obtained through image analysis. Permeability measurement revealed scaffold permeability to increase with fibrinogen concentration, much like average fiber diameter and pore size. Comparison between the two measurement methods demonstrated the efficacy of the flowmeter as a way to measure scaffold features. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Influence of nanohydroxyapatite patterns deposited by electrohydrodynamic spraying on osteoblast response
Authors: Thian E. S. , Huang J. , Ahmad Z. , Edirisinghe M. J. , Jayasinghe S. N. , Ireland D. C. , Brooks R. A. , Rushton N. , Best S. M. , Bonfield W.
Published: August 2007

Electrohydrodynamic spraying has been used to produce patterns of line width up to 100 μm in size on glass discs, using nanohydroxyapatite (nHA). A human osteoblast (HOB)‐like cell model was then used to study the interaction between the HOB cells and nHA patterns in vitro. Growth of the cells was significantly increased (p < 0.05) on the nHA surfaces. In addition, HOBs attached and spread well, secreting extracellular matrix. It was found that a confluent, aligned cell layer was achieved on nHA patterns by day 9. Immunofluorescent staining indicated that these cells showed elongated nuclei, enhanced adhesion (vinculin adhesion plaques) and a well‐aligned cytoskeleton (actin stress fibres). This work suggests that this type of spraying may provide a route for the production of nanoscale features on implants for biomedical applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Vascular cell viability on polyvinyl alcohol hydrogels modified with water‐soluble and ‐insoluble chitosan
Authors: Mathews D. T. , Birney Y. A. , Cahill P. A. , McGuinness G. B.
Published: August 2007

Polyvinyl alcohol (PVA) hydrogels blended with chitosan or other biological macromolecules have shown promise for cell culture and tissue engineering. This study investigates the attachment and growth of bovine aortic endothelial (BAEC) and smooth muscle cells (BASMC) on the PVA hydrogels modified with water soluble and water insoluble chitosan. Cell adhesion on the surface of the membranes was examined by phase constrast microscopy while cell morphologies were studied using immunocytochemistry staining with EC and SMC specific biomarkers (F‐actin and α actin respectively). Cells cultured on 6% PVA, 0.4% chitosan (water soluble and insoluble) hydrogel membranes displayed excellent adhesion and spreading characteristics, in addition to negligible cell structural morphological changes in comparison to a polystyrene control. Similar vascular cell adhesion features were apparent on PVA membranes blended with water‐soluble and ‐insoluble chitosan. Fluorescent activated cell sorter (FACS) analysis was used to determine BAEC and BASMC proliferation and cell viability. Apoptotic levels in BAEC after 7 days were 12.8% ± 2.5% on the PVA‐ chitosan WS‐1 membrane and 10.1% ± 1.5% on the control well (n = 3) while comparable results were also noted for BASMC. Equivalent proliferative activity was apparent for BAEC on the control and PVA‐chitosan membrane after 7 days, while BASMC showed increased proliferative activity on the membranes. These results indicate that the PVA‐chitosan blended hydrogel membranes show promise for cell culture and tissue engineering applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
N3‐Substituted thymidine analogues III: radiosynthesis of N3‐[(4‐[18F]fluoromethyl‐phenyl)butyl]thymidine ([18F]‐FMPBT) and N3‐[(4‐[18F]fluoromethyl‐phenyl)pentyl] thymidine ([18F]‐FMPPT) for PET
Authors: Ghosh Pradip , Gelovani Juri G. , Alauddin Mian M.
Published: August 2007

Radiosyntheses of two N3‐substituted thymidine analogues, N3‐[(4[18F]fluoromethyl‐phenyl)butyl]thymidine ([18F]‐FMPBT) and N3‐[(4[18F]fluoromethyl‐phenyl)pentyl]thymidine ([18F]‐FMPPT), are reported. The precursor compounds 9 and 10 were synthesized in six steps and the standard compounds 13 and 14 were synthesized from these precursors. For radiosynthesis, compounds 9 and 10 were fluorinated with n‐Bu4N[18F] to produce [18F]‐11 and [18F]‐12, which by acid hydrolysis yielded [18F]‐13 and [18F]‐14, respectively. The crude products were purified by high‐performance liquid chromatography to obtain [18F]‐FMPBT and [18F]‐FMPPT. The average decay‐corrected radiochemical yield for [18F]‐13 was 15% in five runs, and that for [18F]‐14 was 10% in four runs. The radiochemical purity was >99% and the specific activity was >74 GBq/µmol at the end of synthesis. The synthesis time was 80–90 min from the end of bombardment. Copyright © 2007 John Wiley & Sons, Ltd.
“Soluble” adenylyl cyclase‐generated cyclic adenosine monophosphate promotes fast migration in PC12 cells
Authors: Young Jennifer J. , Mehdi Amna , Stohl Lori L. , Levin Lonny R. , Buck Jochen , Wagner John A. , Stessin Alexander M.
Published: August 2007

In a model for neuronal movement, PC12 cells undergo fast migration in response to nerve growth factor (NGF) and phorbol ester (PMA). We previously showed that NGF increases intracellular cAMP via activation of soluble adenylyl cyclase (sAC). In this report, we demonstrate that sAC activation is an essential component of NGF‐ + PMA‐induced fast migration in PC12 cells. Interestingly, PMA also raises intracellular cAMP but does so by stimulating transmembrane adenylyl cyclases (tmAC); however, this tmAC‐generated cAMP does not contribute to fast migration. Therefore, cells must possess independent pools of cAMP capable of modulating distinct functions. © 2007 Wiley‐Liss, Inc.
Temperature‐dependent neuronal regulation of arterial blood flow in rat cranial dura mater
Authors: Holom Vigdis H. , Messlinger Karl , Fischer Michael J.M.
Published: August 2007

Several endogenous factors such as calcitonin gene‐related peptide (CGRP), nitric oxide, and histamine have been found to affect meningeal blood flow. A possible regulation of meningeal blood flow by thermosensitive neurons has not been examined so far. We monitored meningeal arterial blood flow with laser Doppler flowmetry in anesthetized rats. A vortex thermode was used to control the temperature of the exposed dura mater. After fast heating from 36°C to 45°C, meningeal blood flow increased slowly within 5 min. Immediately after fast cooling to 36°C, the flow transiently increased before it returned to the initial basal level. After the application of lidocaine onto the dura mater, the heating‐induced flow increase was greater and the transient cooling‐induced flow increase was reduced, indicating the involvement of neuronal mechanisms. Furthermore, after topical application of phenylephrine, the cooling‐induced response was increased, and following topical application of phentolamine the heating‐induced flow increase was higher. The flow changes evoked by thermal stimulation were unaffected by high concentrations of 1) cimetidine, 2) a vasoactive intestinal polypeptide antagonist and the CGRP receptor antagonists, 3)CGRP8–37, and 4) BIBN4096BS. We conclude that activation of temperature‐sensitive meningeal afferents can regulate the dura mater blood flow by a sympathetic reflex. © 2007 Wiley‐Liss, Inc.
Testate amoebae as proxies for mean annual water‐table depth in Sphagnum‐dominated peatlands of North America
Authors: Booth Robert K.
Published: August 2007

Peatland‐inhabiting testate amoebae are sensitive indicators of substrate‐moisture conditions and have increasingly been used in palaeohydrological studies. However, to improve accuracy of testate‐amoeba‐based hydrological inferences, baseline ecological data on rare taxa, a larger geographic network of calibration sites, and incorporation of long‐term estimates of water‐table depth are needed. Species–environment relationships at 369 sites from 31 peatlands in eastern North America were investigated. Long‐term estimates of water‐table depth were obtained using the method of polyvinyl (PVC) tape‐discolouration. Transfer functions were developed using a variety of models, and validated through jackknifing techniques and with an independent dataset where water‐table depths were directly measured throughout the growing season. Results indicate that mean annual water‐table depth can be inferred from testate amoeba assemblages with a mean error of 6 to 8 cm, although there is a slight systematic bias. All transfer function models performed similarly and produced similar reconstructions on a fossil sequence. In a preliminary effort towards development of a comprehensive North American calibration dataset, data from this study were combined with previous studies in Michigan and the Rocky Mountains (n = 650). This combined dataset had slightly larger mean errors of prediction (8–9 cm) but includes data for several rare taxa. Copyright © 2007 John Wiley & Sons, Ltd.
Pasteurized autograft‐prosthesis composite for reconstruction of proximal tibia in 13 sarcoma patients.
Authors: Jeon Dae‐Geun , Kim Min Suk , Cho Wan Hyeong , Song Won Seok , Lee Soo‐Yong
Published: August 2007

Background

The purpose of this study is to ascertain the survival of the pasteurized autograft‐prosthesis composite and functional outcome of this procedure, and to evaluate the complications including nonunion, infection, loosening, bony resorption, and fracture.

Methods

We retrospectively reviewed 13 proximal tibial sarcoma patients who underwent tibia reconstructions with using a pasteurized autograft‐prosthesis between 1993 and 2003.

Results

Four patients underwent removal of the composite with a minimum follow‐up of 11 months (average: 43 months, range: 11–75 months). The survival rate of the 13 composites, as calculated by the Kaplan–Meier method, was 76.9% at 5 years. The primary cause of removing the composite was infection in three patients and loosening in one patient. The average MSTS functional score of 11 patients was 23.6 ± 3.3 (79%). Nonunion was identified in four patients, while infection developed in three patients. Loosening of the stem and resorption of the pasteurized bone was detected in one case each. No patient developed fracture of autograft.

Conclusions

Our data suggest that the pasteurized autograft‐prosthesis has comparable functional outcome and complication rates as other methods, such as endoprosthesis and allograft‐prosthetic composite and it offers a reconstructive option for surgeons who do not have access to large allograft banks. J. Surg. Oncol. 2007;96:590–597. © 2007 Wiley‐Liss, Inc.
Residual disease after re‐excision for tumour‐positive surgical margins in both ductal carcinoma in situ and invasive carcinoma of the breast: The effect of time
Authors: van der Velden A.P. Schouten , Van de Vrande Simon L.B. , Boetes Carla , Bult Peter , Wobbes Theo
Published: August 2007

Background and Objectives

To assess the effect of time on finding residual breast cancer in re‐excision specimens after non‐radical breast‐conserving surgery for both DCIS and invasive breast carcinoma.

Methods

315 breast‐conserving surgical procedures with tumour‐positive margins were retrospectively reviewed. The significance of association between the presence of finding residual tumour in the re‐excision specimen and mean time interval was calculated with Student's t‐test. A multivariate logistic regression model was used to assess the independent relative risk of time on presence of residual tumour.

Results

Residual tumour was found in 240 (76.2%) of the re‐excision specimens. For primary invasive carcinomas time was a risk‐reducing factor for finding residual disease (OR 0.89, 95% CI 0.82–0.98, P = 0.01). If invasive carcinoma was transected, the absence of residual disease was significantly related with a longer mean time interval (OR 0.98, 95% CI 0.95–0.99, P = 0.04).

Conclusions

An increased time interval between primary surgery and re‐excision for tumour‐positive surgical margins for invasive carcinoma is associated with a decreased incidence of finding residual tumour. This could be explained by inflammatory responses after surgical trauma. For DCIS there was no influence of time on finding residual tumour, which could be explained by a more protective microenvironment of DCIS or re‐growth of surviving malignant cells. J. Surg. Oncol. 2007;96:569–574. © 2007 Wiley‐Liss, Inc.
Functional Graft Poly(N‐isopropyl acrylamide)s Using Reversible Addition‐Fragmentation Chain Transfer (RAFT) Polymerisation
Authors: Carter Steven R. , England Richard M. , Hunt Barry J. , Rimmer Stephen
Published: August 2007

A series of NIPAM/4‐vinyl benzyl chloride copolymers were substituted with 4(5)‐imidazole dithioic acid or N‐pyrrole dithioic acid to form multi‐functional linear dithioate‐functional polymers, which can be used as macromolecular transfer agents in a controlled radical polymerisation (RAFT) process. The presence of imidazole dithioate or N‐pyrrole dithioate units along the NIPAM copolymer was determined by 1H NMR, which showed broad CH‐imidazole or CH‐N‐pyrrole resonances. Subsequent reaction of these multi‐branch point polymers to produce graft polymers was achieved by reaction with NIPAM in the presence of AIBN. The graft polymers are produced as mixtures containing the desired product and linear polymer. The linear polymer is produced following transfer to the pendant dithioate group. Some of the branched polymers formed from the imidazole dithioate polymers were insoluble in water whilst others were found to be water soluble only in the presence of copper(II) ions. The use of N‐pyrrole dithioate groups was found to substantially increase the solubility of the branched polymers in conventional solvents.

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Synthesis and Self‐Assembly of Brush‐Rod Diblock Copolymers in the Mixed Solvent of THF/H2O
Authors: Cao Hongqing , Lin Weiran , Liu Anhua , Zhang Jie , Wan Xinhua , Zhou Qifeng
Published: August 2007

Two amphiphilic brush‐rod block copolymers, PEGMA37‐b‐MBPS87 and PEGMA37‐b‐MBPS141, were synthesized via ATRP of poly(ethylene glycol)monomethyl ether methacrylate (PEGMA) and (+)‐2,5‐bis[4′‐((S)‐2‐methylbutoxy)phenyl]styrene (MBPS). The self‐assembly of the copolymers in THF/H2O was induced by different methods. Spheres were dominant morphologies of PEGMA37‐b‐MBPS87 regardless of the initial concentration and the rate of water addition. Increase of the length of hydrophobic block, as in PEGMA37‐b‐MBPS141, led to the coexistence of primary spheres, large compound spherical and rod‐like micelles at a slow water addition rate. Injecting water into the THF solution of PEGMA37‐b‐MBPS141 quickly or pouring the THF solution into large amount of water resulted only in the formation of spheres.

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Diminished fatigue at reduced muscle length in human skeletal muscle
Authors: Lee Samuel C. K. , Braim Anthony , Becker Cara N. , Prosser Laura A. , Tokay Ann M. , Binder‐Macleod Stuart A.
Published: August 2007

Understanding muscle fatigue properties at different muscle lengths is essential to improve electrical stimulation applications in which impaired muscle is activated to produce function or to serve as an orthotic assist. This study examined the effects of muscle length on fatigue in human quadriceps muscle. Twelve healthy subjects were tested at short and long muscle lengths (15° and 90° of knee flexion, respectively) before and after a fatigue‐producing protocol using low‐, high‐, and variable‐frequency testing trains. Greater fatigue was observed at the longer muscle length, supporting the notion that fatigue is largely dependent upon metabolic factors. Fatigue, however, was characterized by greater attenuation of low‐ than high‐frequency responses (i.e., low‐frequency fatigue, LFF) at the long length. This observation, accompanied by the fact that variable‐frequency trains produced greater augmentations in force production than comparable low‐frequency trains at the longer length, suggests that excitation–contraction coupling impairment is also a contributing factor to fatigue and plays a greater role at the more fatigue‐susceptible longer muscle length. Muscle Nerve, 2007
Proteomic analysis of rabbit tear fluid: Defensin levels after an experimental corneal wound are correlated to wound closure
Authors: Zhou Lei , Beuerman Roger W. , Huang Liqun , Barathi Amutha , Foo Yong Hwee , Li Sam F. Y. , Chew Fook Tim , Tan Donald
Published: August 2007

The cornea is the major refracting optical element of the eye and therefore critical for forming a retinal image. The exposed surface of the eye is protected from pathogens by the innate immune system whose components include defensins, naturally occurring peptides with antimicrobial properties, and the physical barrier formed by the outer epithelial layer of the cornea. The proteomic approach has revealed that tear levels of defensins are correlated with the course of healing of an experimental corneal wound. Tears were collected from New Zealand White rabbits prior to (day 0) and daily for 5 days (days 1–5) following a standard unilateral 6 mm diameter corneal epithelial abrasion. Tear protein profiles obtained from wounded and contra‐lateral control eyes were compared using SELDI ProteinChip technology. Peptides and proteins of interest were purified by RP‐HPLC and characterized by nanoESI‐MS/MS. Mass spectra of tears on post‐wound day 1, revealed 13 peaks whose level decreased and five that increased. During wound healing the tear protein profile correlated with wound closure. An important finding was that the levels of rabbit defensins (NP‐1 and NP‐2), which were elevated after wounding returned to normal levels by the time the corneal abrasion healed. Relative quantification of NP‐2 in tear fluid prior to (day 0) and after corneal wounding (days 1– 3) was determined using iTRAQ technology. A corneal wound eliminates the barrier function of innate immunity and puts the cornea at risk from microbial attack until the epithelial cells restore the surface barrier. The increased availability of defensins in the tears during healing suggests that these peptides could protect the cornea from microbial attack during a period of increased vulnerability.
The link between the ionization potential and heat of formation for organic homologous compounds
Authors: Cao Chenzhong
Published: August 2007

Based on the relationship between the heat of formation and the change of valence electronic energy in the formation of a compound from its component atoms, and combined with the relationship between the first ionization potential and the average valence electronic energy, the direct link of ionization potential, Ip, with the heat of formation, ΔH0f, was deduced for organic homologous compounds, that is,

where Nve,m is the number of valence electrons in molecule, SVEEx is the sum of valence electronic energy of isolated atoms forming the molecule, the term $(\Sigma {\rm SVEE}_x - \Delta H_{_{\rm f} }^{\rm 0} )$ expresses the initial‐state effect of the molecule, and the symbol Rm represents its final‐state effect (polarizability effect). The above equation was confirmed by the correlations between the ionization potentials and the heat of formation of alkanes, alkenes, monosubstituted alkanes RY (Y = OH, NH2, SH, Cl, Br, and I), in which all the expressions have good correlations with correlation coefficients more than 0.9990. With the obtained correlation equations, the ionization potentials of some monosubstituted alkanes were predicted from their experimental heats of formation. The result provides a new insight into the intercorrelation between the ionization potential and the heat of formation for organic homologous compounds. Copyright © 2007 John Wiley & Sons, Ltd.
Self‐assembly of amphiphilic tris(2,2′‐bipyridine)ruthenium‐cored star‐shaped polymers
Authors: Zhou Guangchang , He Jibao , Harruna Issifu I.
Published: August 2007

Amphiphilic tris(2,2′‐bipyridine)ruthenium‐cored star‐shaped polymers consisting of one polystyrene block and two poly(N‐isopropylacrylamide) blocks were prepared by the “arm‐first” method in which RAFT polymerization and nonconvalent ligand–metal complexation were employed. The prepared amphiphilic star‐shaped metallopolymers are able to form micelles in water. The size and distribution of the micelles were studied by dynamic light scattering and transmission electron microscopy techniques. Preliminary studies indicate that the polymer concentration and the hydrophilic poly(N‐isopropylacrylamide) block length can affect the morphologies of the formed metal‐interfaced core–shell micelles in water. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4204–4210, 2007
Synthesis and characterization of novel poly(p‐phenylenevinylene) derivatives containing phenothiazine‐5‐oxide and phenothiazine‐5, 5‐dioxide moieties
Authors: Yang L. Y. , Wang C. , Li L. Q. , Janietz S. , Wedel A. , Hua Y. L. , Yin S. G.
Published: August 2007

PPV‐based copolymers containing phenothiazine‐5‐oxide and phenothiazine‐5, 5‐dioxide moieties have been successfully synthesized by Wittig‐Horner reaction and characterized by means of UV‐vis, photoluminescence, electroluminescence spectra, and cyclic voltammetry. All of these copolymers can be dissolved in common organic solvents such as chloroform, tetrahydrofuran, and toluene. The PL maxima in the film state are located at 582, 556, and 552 nm for P1, P2, and P3, respectively. The HOMO and LUMO levels of P2 are found to be −5.21 and −2.68 eV, respectively; whereas those of P3 are found to be −5.26 and −2.71 eV, respectively. The cyclic voltammetry result indicates that the conversion of electron‐donating sulfide to electron‐withdrawing sulfoxide or sulfone group in polymers plays a dominating role in increasing its oxidation potential. Yellowish‐green light ranging from 568 to 540 nm was observed for the single layer device with the configuration of ITO/Polymer/Ca/Al. Double layer devices with Zn (BTZ)2 as a hole blocking layer exhibited enhanced EL performance compared to the single layer devices. The maximum brightness of the double layer devices of P1, P2, and P3 is 278, 400, and 796 cd/m2, respectively. The results of EL and electrochemical analyses revealed that they are promising candidate materials for organic, light‐emitting diodes with hole‐transporting ability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4291–4299, 2007
Miscibility and crystallization behavior in blends of poly(methyl methacrylate) and poly(vinylidene fluoride): Effect of star‐like topology of poly(methyl methacrylate) chain
Authors: Fan Wenchun , Zheng Sixun
Published: August 2007

A tetraarmed star‐shaped poly(methyl methacrylate) (s‐PMMA) was synthesized via atom transfer radical polymerization with 2‐bromoisobutyryl pentaerythritol as the initiator. For comparison, a linear PMMA with the identical molecular weight (l‐PMMA) was also prepared. The blends of the two PMMA samples with poly (vinylidene fluoride) (PVDF) were prepared to investigate the effect of macromolecular topological structure on miscibility and crystallization behavior of the binary blends. The behavior of single and composition‐dependent glass transition temperatures was found for the blends ofs‐PMMA with PVDF, indicating that thes‐PMMA is miscible with PVDF in the amorphous state just likel‐PMMA. The miscibility was further evidenced by the depression of equilibrium melting points. It is found that the blends ofs‐PMMA and PVDF displayed the largerkvalue of Gordon–Taylor equation than the blends ofl‐PMMA and PVDF blends. According to the depression of equilibrium melting points, the intermolecular parameters for the two blends were estimated. It is noted that thes‐PMMA/PVDF blends displayed the lower interaction parameter thanl‐PMMA/PVDF blends. The isothermal crystallization kinetics shows that the crystallization of PVDF in the blends containings‐PMMA is faster than that in the blends containing the linear PMMA. The surface‐folding free energy of PVDF chains in the blends containings‐PMMA is significantly lower than those in the blends containingl‐PMMA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2580–2593, 2007
Templated i‐PVD of Metallic Nanodot Arrays
Authors: Yuan Luqi , Zhong Xiaoxia , Levchenko Igor , Xia Yuxing , Ostrikov Kostya
Published: August 2007

The results of numerical simulation of plasma‐based, porous, template‐assisted nanofabrication of Au nanodot arrays on highly‐doped silicon taking into account typical electron density of low‐temperature plasma of 1017–1018 m−3 and electron temperature of 2–5 eV are reported here. Three‐dimensional microscopic topography of ion flux distribution over the outer and inner surfaces of the nanoporous template is obtained via numerical simulation of Au ion trajectories in the plasma sheath, in the close proximity of, and inside the nanopores. It is shown that, by manipulating the electron temperature, the cross‐sheath potential drop, and by additionally altering the structure of the nanoporous template, one can control the ion fluxes within the nanopores, and eventually maximize the ion deposition onto the top surface of the developing crystalline Au nanodots (see top panel in the figure). In the same time, this procedure allows one to minimize amorphous deposits on the sidewalls that clutter and may eventually close the nanopores, thus disrupting the nanodot growth process, as it is shown in the bottom panel in the figure on the right.

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Caribbean transnational migration behaviour: reconceptualising its ‘strategic flexibility’
Authors: Conway Dennis
Published: August 2007

Building on a considerable body of extant literature, and critically assessing its strong and weak (or overlooked) conceptual explanations and observations, this reconceptualisation of Caribbean transnational migrant behaviour updates the theoretical account of what is now an increasingly prevalent mobility process in the region. Utilising a structuration construct in which a key conceptual base is a behavioural (agency) notion of strategic flexibility, transnational migrants operating within Caribbean family networks are situated in their multi‐local transnational social fields and resultant distant‐but‐linked community structures. A ‘moorings’ construct (first offered by Moon in 1995) further enables the portrayal of transnational migrants' personal interactions and migration behaviours in multicultural contexts. It allows the examination of their aggregate outcomes in relation to the micro‐ and mesostructural contexts of institutional/familial/communal decision‐making and action as they play themselves out in continuous time. ‘Homes’ and ‘homes away from home’ provide the microgeographical ‘roots’ of migrants' transnational existence, of their experiences, identities, and degrees of national and transnational consciousness. Copyright © 2007 John Wiley & Sons, Ltd.
Fertility, age structure and demographic transition in the former Soviet republics: the Central Asian Republics in focus
Authors: Gentile Michael
Published: August 2007

Synthesising data from Soviet and post‐Soviet statistical sources, this paper provides a general overview of some of the major population trends of the Former Soviet Union with a special focus on the Central Asian Republics. The paper investigates the characteristics of the countries' vital statistics, paths of demographic transition and age structure as they have developed during the past 50–60 years. Particular emphasis is placed upon data and methodological problems encountered when doing population research on the region. Copyright © 2007 John Wiley & Sons, Ltd.
Self‐organized InAs quantum dots grown in a V‐groove InGaAs quantum wire
Authors: Son Chang‐Sik , Ogura Mustuo , Sung Yun Mo , Leem Si Jong , Kim Tae Geun
Published: August 2007

Self‐organized InAs quantum dots (QDs), by the Stranski–Krastanow mode, have been grown by using low‐pressure metalorganic chemical vapor deposition on V‐groove GaAs substrates. By adjusting the flow rate of AsH3 during the growth of InAs QDs, a one dimensional InAs QD array was successfully formed along the [0$ \bar 1 $1] direction only at the bottom of V‐grooves. No QDs were observed on the sidewalls and the surface of the mesa top. The InAs QDs took on an oval shape. They were spatially well‐isolated along the [0$ \bar 1 $1] direction with a line density of 3 × 103 cm–1. These low‐density InAs QDs are expected to be used in areas of quantum information and quantum computing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation between glass forming tendency and rate of crystallization in glassy Se100–xTex and Se100–xInx alloys
Authors: Mehta N. , Kumar D. , Kumar A.
Published: August 2007

The rate of crystallization in glassy Se100–x Tex (5 ≤ x ≤ 30) and Se100–x Inx (5 ≤ x ≤ 30) alloys has been determined by using the Arrhenius dependence of the rate constant of crystallization. For this, the pre‐exponential factor K0 of the rate constant K (T) in these alloys has been determined using isothermal and non‐isothermal methods. The glass forming tendency is determined using the Sun–Rawson–Minaev criterion. A correlation is observed between the glass forming tendency and the rate of crystallization in these alloys. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of dendrite‐like Au nanostructures and their enhanced photoluminescence emission
Authors: Hu Ying , Pan Nan , Zhang Kun , Wang Zhenxing , Hu Hailong , Wang Xiaoping
Published: August 2007

Special hierarchical dendrite‐like Au (DLAu) nanostructures were fabricated facilely between the gaps of Au electrodes by an electrochemical method. The composition, morphology and crystallinity of the DLAu nanostructures were characterized using energy dispersive spectroscopy, field emission scanning electron microscopy and X‐ray diffraction, respectively. The formation of these nanostructures is attributed to the distribution of the local electrical field between the Au electrodes and a diffusion‐limited aggregation process. Photoluminescence (PL) having an emission peak near 530 nm is observed from these nanostructures, which is attributed to the recombination of the s–p band electrons near the Fermi energy with the d band holes in the DLAu nanostructures generated by optical excitation. We believe that such PL enhancement compared to a smooth Au film is due to the local‐field enhancement from the surface plasmon resonance of the DLAu nanostructures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallisation and magnetic behaviour of amorphous and nanocrystalline Fe81–x –yNixCoyZr7B12 alloys
Authors: Kopcewicz M. , Latuch J. , Kulik T.
Published: August 2007

The amorphous precursors Fe81–x –y Nix Coy Zr7B12 (x = 50, 40, 30, 20; y = 0, 10, 20), prepared by the melt quenching technique, have been characterised in terms of their ability to form nanocrystalline grains on annealing. The crystallisation process was studied in detail using Mössbauer spectroscopy, X‐ray diffraction (XRD) and differential scanning calorimetry measurements. The crystalline phases formed were identified and their transformation versus annealing temperature was followed. Bulk and surface crystallisation of amorphous precursors was compared using conversion electron Mössbauer spectroscopy. The size of nanograins was estimated from the XRD results using the Scherrer formula. The magnetic properties of amorphous and nanocrystalline Fe81–x –y Nix Coy Zr7B12 alloys were studied using an unconventional ‘rf‐Mössbauer’ technique. The rf‐Mössbauer technique provides information on the soft magnetic behaviour of alloys. The rf sidebands observed are directly related to magnetostriction and their presence provides a good test for the formation of the nanocrystalline alloy. The rf‐Mössbauer results revealed that the anisotropy field increased significantly with the introduction of Co. The rf‐Mössbauer measurements were accompanied by conventional measurements of hysteresis loops that fully supported the rf‐Mössbauer results. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectrometer for the investigation of temperature dependent Ps formation and material dependent moderation efficiency
Authors: Brunner T. , Hugenschmidt C.
Published: August 2007

The moderation efficiency of the commonly used positron moderators, such as tungsten or solid rare gases, is very low and amounts to less than 10‐2. For this reason a novel spectrometer was developed that enables the determination of the positron workfunction ϕ+ and the temperature dependent moderation efficiency ε of various sample materials. An additional feature of the experimental setup is the ability to investigate the temperature dependence of positronium (Ps) formation. Either with three BGO detectors the emitted gamma‐rays of the ortho‐Ps decay can be detected in coincidence or the decay spectrum can be measured with a high resolution Ge detector. The layout of this novel spectrometer and simulations are presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reflection high‐energy positron diffraction study of surface super‐structures
Authors: Kawasuso A. , Fukaya Y. , Hayashi K. , Hashimoto M. , Ichimiya A.
Published: August 2007

In this work, we studied a few surface super‐structures using reflection high‐energy positron diffraction (RHEPD). We found that the RHEPD pattern from the Si(111)‐7×7 surface exhibits different features from that of electron diffraction. The difference is explained as a strong thermal diffuse scattering of positrons at the first surface layer. We also studied the phase transition of the Si(111)‐√3×√3‐Ag surface. We found that the surface sensitive diffraction spots exhibit peculiar temperature dependences. Based on theoretical considerations, we interpreted the temperature dependences in terms of the order‐disorder phase transition. Furthermore, we succeeded in determining a unique structure of the Si(111)‐√21×√21‐Ag surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlated, ab initio electron propagators in the study of molecular wires: Application to a single molecular bridge placed between two model leads
Authors: Sterling Mark R. , Dolgounitcheva O. , Zakrzewski V.G. , Dahnovsky Yu. , Ortiz J. V.
Published: August 2007

A correlated, ab initio electron propagator approach is tested for a model system containing 1,4‐benzene‐dithiolate attached to two gold or two aluminum atoms. Qualitative agreement with available experiment is achieved for the gold dithiolate system. Similar current and conductance curves obtain for both metal leads when the Fermi energy is set to −1.0 eV. A molecular orbital analysis is given for the gold dithiolate system. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Investigation of analytical variation in metabonomic analysis using liquid chromatography/mass spectrometry
Authors: Sangster Tim P. , Wingate Julie E. , Burton Lyle , Teichert Friederike , Wilson Ian D.
Published: August 2007

Sources of analytical variation in high‐performance liquid chromatography/mass spectrometry (HPLC/MS), such as changes in retention, mass accuracy or signal intensity, have been investigated to assess their importance as a variable in the metabonomic analysis of human urine. In this study chromatographic retention and mass accuracy were found to be quite reproducible with the most significant source of analytical variation in the data sets obtained being the result of changes in detector response. Depending on the signal intensity threshold used to define the presence of a peak a sample component could be present in some replicate injections and absent in others within the same run. The implementation of a more sophisticated data software analysis package was found to greatly reduce the impact of detector response variability resulting in improved data analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of some stilbenes in Italian wines by liquid chromatography/tandem mass spectrometry
Authors: Buiarelli Francesca , Coccioli Franco , Jasionowska Renata , Merolle Mirco , Terracciano Alessandro
Published: August 2007

Stilbenes from grapes and wines play a central role in the human diet because of their antioxidant, antimutagenic and anticarcinogenic properties. We describe a method for the direct determination of some stilbenes (cis‐ and trans‐resveratrol, cis‐ and trans‐resveratrol glucoside, cis‐ and trans‐piceatannol, and cis‐ and trans‐piceatannol glucoside) in wine by high‐performance liquid chromatography/mass spectrometry using a triple quadrupole (QqQ) mass spectrometer, in multiple reaction monitoring (MRM) mode, acquiring two diagnostic product ions from the chosen precursor. All the target analytes were separated on a C‐18 column using gradient elution, in a single run. Electrospray ionization (ESI) in negative ion mode gives higher sensitivity for all the target compounds than atmospheric pressure chemical ionization (APCI). For the identification of piceatannol glucoside (astringin), because of the lack of a suitable standard, an HPLC/TOFMS method was used. The method permits direct injection of samples and it is time‐saving, removing the need for sample pre‐treatment. The detection limits were 48.0 ng mL−1 for cis‐ and trans‐resveratrol and for cis‐ and trans‐resveratrol glucoside, and 50.0 ng mL−1 for cis‐ and trans‐piceatannol. The procedure proved to be simple and suitable for routine and confirmatory purposes. A total of 19 red and 3 white Italian wines were analyzed and differences in the stilbene composition were found among these samples. Copyright © 2007 John Wiley & Sons, Ltd.
Values and sustainable consumption behavior of women: a Turkish sample
Authors: Şener Arzu , Hazer Oya
Published: August 2007

We conducted this study to test the impact of values on women's sustainable consumption behavior. The sample consisted of 600 women in Ankara, Turkey. We used a list of 23 values from five value types from Schwartz's model. We measured sustainable consumption behavior with a five‐point scale for 14 environment‐friendly behaviors. We found that the values of this sample of Turkish women are related to their behaviors. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Clustering of significant genes in prognostic studies with microarrays: Application to a clinical study for multiple myeloma
Authors: Matsui Shigeyuki , Yamanaka Takeharu , Barlogie Bart , Shaughnessy John D. , Crowley John
Published: August 2007

When a large number of genes are significant in correlating microarray gene expression data with patient prognosis, clustering of significant genes may be effective not only for further dimension reduction but also for identifying co‐regulated genes that belong to the same molecular pathway related to disease biology and aggressiveness. Moreover, a reduced feature, such as the average expression across samples for a cluster of significant genes, can play an important role in reducing variance in prediction analysis. We propose a simple procedure to select gene clusters that have strong marginal association with survival outcome from a large pool of candidate hierarchical clusters of significant genes. Selected gene clusters can have better predictive capability than the other gene clusters and singleton genes. Application of such clustering to the data set from a clinical study for patients with multiple myeloma and associated microarrays is given. Copyright © 2007 John Wiley & Sons, Ltd.
STXXL: standard template library for XXL data sets
Authors: Dementiev R. , Kettner L. , Sanders P.
Published: August 2007

We present the software library STXXLthat is an implementation of the C++ standard template library (STL) for processing huge data sets that can fit only on hard disks. It supports parallel disks, overlapping between disk I/O and computation and it is the first I/O‐efficient algorithm library that supports the pipelining technique that can save more than half of the I/Os. STXXLhas been applied both in academic and industrial environments for a range of problems including text processing, graph algorithms, computational geometry, Gaussian elimination, visualization, and analysis of microscopic images, differential cryptographic analysis, etc. The performance of STXXLand its applications are evaluated on synthetic and real‐world inputs. We present the design of the library, how its performance features are supported, and demonstrate how the library integrates with STL. Copyright © 2007 John Wiley & Sons, Ltd.
The benefits of posing application software as a language interpreter
Authors: Van Snyder W.
Published: August 2007

Complicated and comprehensive software that is meant to execute in a non‐interactive or semi‐interactive mode needs to be configured to carry out the desired tasks, needs to carry out those tasks efficiently, needs to be extensible to take on additional ambitions, and needs to be maintainable. To reduce costs, it is helpful if experts in the discipline to which the program applies can configure and operate the program without needing to become expert software engineers and without needing to become familiar with the internal details of the program, and if software engineers who develop and maintain the program need not become experts in its target discipline. Progress toward these goals can be advanced by posing the software as a language interpreter. We describe the application of this principle to ground‐based data analysis software for the Microwave Limb Sounder instrument on the NASA Earth Observing System Aura satellite, but we believe the principle has substantially broader applicability. Copyright © 2007 John Wiley & Sons, Ltd.
Modular formal verification of specifications of concurrent systems
Authors: Gradara Sara , Santone Antonella , Vaglini Gigliola , Villani Maria Luisa
Published: August 2007

In this paper, we propose a bottom‐up approach for the verification of systems with modular structure: we prove that when the modules are composed in specific ways, the complete software system verifies a composition of the properties each component does. We focus on the process of upgrading systems with new functionalities, where the validity of old requirements needs to be ensured, but also an understanding of the new properties the upgraded system would enjoy is useful. In this work, we assume each component to be specified by a CCS process, and the properties to be expressed by selective mu‐calculus formulae. Copyright © 2007 John Wiley & Sons, Ltd.
Impact of the collaboratives for excellence in teacher preparation program
Authors: Lawrenz Frances , Huffman Douglas , Gravely Amy
Published: August 2007

This study investigated the national impact of the Collaboratives for Excellence in Teacher Preparation program (CETP). Impact of the program was examined in two different settings: institutions of higher education, and K–12 science and mathematics classrooms. The focus of this study was to determine the impact of the CETP program on the institutional culture and collaborations among faculty, and changes in instructional techniques used by higher education faculty and K–12 teachers. Data were gathered over a 3‐year period from 12 different CETP projects. At the higher education level faculty reported more collaboration and a slight increase in the use of standard‐based teaching. At the K–12 level, students of teachers who were prepared by the CETP program viewed classroom instruction as slightly more standards‐based than comparable students of non‐CETP prepared teachers. Additionally, external observers rated classes taught by teachers educated in CETP projects as more standards‐based than classes taught by non‐CETP teachers educated in other programs. Implications of the results for national large‐scale reform of science and mathematics education are discussed. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 1348–1369, 2007