bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(ethylene imine)‐g‐chitosan using EX‐810 as a spacer for nonviral gene delivery vectors
Authors: Lou Yu‐Lun , Peng Yu‐Shiang , Chen Bing‐Hung , Wang Li‐Fang , Leong Kam W. 
Published: April 2008

AbstractPolyelectrolyte complexes have been widely studied as gene carriers in recent years. In this study, poly (ethylene imine) was grafted onto chitosan (PEI‐g‐CHI) as a nonviral gene carrier in order to improve the water solubility as well as the inherent transfection efficiency of chitosan. We present a novel method to conjugate the amine or hydroxyl groups of chitosan (CHI) and the amine groups of PEI through opening the epoxide rings of ethylene glycol diglycidyl ether (EX‐810), which also brings the merits as mentioned in PEGylation chemistry. The degree of substitution of PEI onto CHI was characterized by NMR. The preliminarily cellular mechanisms, from the cellular entry to the endosomal release, were investigated by the correlations among the physicochemical properties of the DNA‐polymer complexes, the buffering capacity of the modified polymer, the cytotoxicity, and the efficiency of the transgene expression. The cytotoxicity assayed by MTT shows that cell viability of PEI‐g‐CHI is higher than CHI especially noticeable at high concentrations using human kidney 293T cells. The efficiency of transgene expression and the amount of intracellular plasmid were monitored using green fluorescent protein (GFP) and visualized by fluorescence microscopy. The transfection efficiency of PEI‐g‐CHI/DNA polyplex is significantly better than CHI/DNA polyplex when using the weight ratios higher than 2.5. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Physicochemical properties, surface active species and formation of reverse micelles in the Cyanex 923‐n‐heptane/cerium(IV)‐H2SO4 extraction system
Authors: Wang Weiwei , Wang Xianglan , Wang Yanliang , Li Deqian , Liao Wuping 
Published: April 2008

AbstractBACKGROUND: The Cyanex® 923 (trialkylphosphine oxides, TRPO)‐n‐heptane/cerium(IV)‐H2SO4 extraction system has been investigated focusing on the physicochemical properties, surface active species and interfacial phenomena. The effects of H2SO4 and Ce(IV) extraction on them were considered.RESULTS: Results showed that the density and refractive index reflect the mass transfer by H2SO4 and Ce(IV) extraction and the change of refractive index was more sensitive than density. The interfacial tension decreased on extraction of H2SO4 but increased on extraction of Ce(IV). The viscosity of the equilibrium organic phase increased abruptly when the extracted H2SO4 concentration in the organic phase reached certain high values. The formation of reversed micelles, with mean diameter of about 10 nm, at high H2SO4 concentrations in the organic phase, is suggested by various measurements such as viscosity, interfacial tension and dynamic light‐scattering (DLS).CONCLUSION: It is suggested that TRPO‐H2SO4 complexes are more surface‐active than TRPO itself and tend to aggregate into reverse micelles by self‐assembling in the organic phase but the Ce(IV)‐TRPO complexes are neutral, less surface‐active than TRPO and not helpful for reverse micelle formation. Copyright © 2008 Society of Chemical Industry
Straight line embeddings of cubic planar graphs with integer edge lengths
Authors: Geelen Jim , Guo Anjie , McKinnon David 
Published: April 2008

AbstractWe prove that every simple cubic planar graph admits a planar embedding such that each edge is embedded as a straight line segment of integer length. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:270‐274, 2008
From Vygotsky to Vygotskian psychology: Introduction to the history of the Kharkov School
Authors: Yasnitsky Anton , Ferrari Michel 
Published: April 2008

AbstractAround the end of the 1920s, Vygotsky introduced his integrative framework for psycho‐logical research to the Soviet Union. This framework was not abandoned and forgotten until its rediscovery in Russia and America in the 1950s, as some claim. In fact, even after his untimely death in 1934, Vygotsky remained the spiritual leader of a group of his for‐mer students and collaborators, who became known as the Kharkov School. This paper reconstructs the early intellectual history of Vygotskian psychology, as it emerged, around the time of Vygotsky's death, in the research program of the Kharkov School.
Gadolinium‐enhanced echo‐planar T2‐weighted MRI of tumors in the extracranial head and neck: Feasibility study and preliminary results using a distributed‐parameter tracer kinetic analysis
Authors: Bisdas Sotirios , Baghi Mehran , Wagenblast Jens , Vogl Thomas J. , Thng Choon Hua , Koh Tong San 
Published: April 2008

AbstractPurposeTo examine the feasibility of first‐pass dynamic contrast‐enhanced (DCE) T2‐weighted MRI of tumors in the extracranial head and neck by applying a distributed‐parameter (DP) tracer kinetic model to quantify the perfusion parameters.Materials and MethodsA total of 16 patients with primary malignant and benign tumors in the head and neck underwent DCE‐MR studies. A spin‐echo (SE) echo‐planar‐imaging (EPI) MR‐sequence was applied for first‐pass DCE‐T2‐weighted imaging. The data were postprocessed applying a DP tracer kinetic model that accounts for capillary‐tissue exchange. Region‐of‐interest (ROI) analysis was performed in the tumor sites and the adjacent normal tissue. Blood flow (F), intravascular blood volume (v1), extravascular extracellular volume (v2), difference in bolus arrival time between arterial input and tissue (t0), intravascular mean transit time (t1), permeability (PS), and extraction ratio (E) maps were generated for each patient.ResultsAll perfusion values in the tumor sites were significantly different (0.000 ≤ P ≤ 0.01) than those in the normal muscle tissue. The median perfusion values in the tumor tissue were: F = 150.5 mL/minute/100 g, v1 = 11.0 mL/100 g, v2 = 31.5 mL/100 g, t0 = 4.5 seconds, t1 = 8.0 seconds, PS = 96.0 mL/minute/100 g, and E = 32.5.ConclusionEPI‐T2‐weighted DCE‐MR in head and neck tumors as well as quantification of the perfusion values using DP model physiologic imaging was feasible and the promising initial results have encourages further validation studies in the future. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
In vivo knee loading characteristics during activities of daily living as measured by an instrumented total knee replacement
Authors: Mündermann Annegret , Dyrby Chris O. , D'Lima Darryl D. , Colwell Clifford W. , Andriacchi Thomas P. 
Published: April 2008

AbstractWe examined the relationship between activity, peak load, medial to lateral load distribution, and flexion angle at peak load for activities of daily living. An instrumented knee prosthesis was used to measure knee joint force simultaneously with motion capture during walking, chair sit to stand and stand to sit, stair ascending and descending, squatting from a standing position, and golf swings. The maximum total compressive load at the knee was highest during stair ascending and descending and lowest during rising from a chair. Maximum total compressive load occurred at substantially different flexion angles ranging from 8.5° during walking to 91.8° during squatting. For all activities, total compressive load exceeded 2 times body weight, and for most activities 2.5 times body weight. Most activities placed a greater load on the medial compartment than the lateral compartment. Activities were grouped into three categories: high cycle loading (walk), high load (stair ascent, descent, and golf), and high flexion angle (chair sit to stand/stand to sit, and squat). The results demonstrate that the forces and motion sustained by the knee are highly activity‐dependent and that the unique loading characteristics for specific activities should be considered for the design of functional and robust total knee replacements, as well as for rehabilitation programs for patients with knee osteoarthritis or following total knee arthroplasty. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1167–1172, 2008
Identification of epidermal L‐tryptophan and its oxidation products by in vivo FT‐Raman Spectroscopy further supports oxidative stress in patients with vitiligo
Authors: Rokos Hartmut , Wood John M. , Hasse Sybille , Schallreuter Karin U. 
Published: April 2008

AbstractIn the past, non‐invasive in vivo FT‐Raman spectroscopy has been used to detect H2O2‐mediated oxidation of methionine to methionine sulfoxide and methionine sulfone, as well as cysteine to cysteic acid, in the sequence of proteins in the epidermis of patients with vitiligo. L‐tryptophan (Trp) is another potential target for this oxidation. Owing to the presence of 10−3M epidermal albumin which contains one Trp residue, it was tempting to follow the oxidation of this amino acid. Using in vivo and in vitro FT‐Raman spectroscopy, we show for the first time that epidermal Trp is oxidised in patients with vitiligo, yielding 5‐OH‐Trp at 930 cm−1 and other oxidation products (i.e. N‐formyl kynurenine and kynurenine) from indole ring oxidation peaking at 1050 cm−1. On the basis of detailed in vitro results, we could conclude that 5‐OH‐Trp as well as formyl kynurenine and kynurenine are formed via H2O2‐mediated Fenton chemistry. These results once again bring out the strength of non‐invasive in vivo FT‐Raman Spectroscopy in dermatology to follow the effect of oxidative stress in the skin of patients with vitiligo. Copyright © 2008 John Wiley & Sons, Ltd.
A field test of group based exposure therapy with 102 veterans with war‐related posttraumatic stress disorder
Authors: Ready David J. , Thomas Kaprice R. , Worley Virginia , Backscheider Andrea G. , Harvey Leigh Anne C. , Baltzell David , Rothbaum Barbara Olasov 
Published: April 2008

AbstractGroup‐based exposure therapy (GBET) was field‐tested with 102 veterans with war‐related posttraumatic stress disorder (PTSD). Nine to 11 patients attended 3 hours of group therapy per day twice weekly for 16–18 weeks. Stress management and a minimum of 60 hours of exposure was included (3 hours of within‐group war‐trauma presentations per patient, 30 hours of listening to recordings of patient's own war‐trauma presentations and 27 hours of hearing other patients' war‐trauma presentations). Analysis of assessments conducted by treating clinicians pre‐, post‐ and 6‐month posttreatment suggests that GBET produced clinically significant and lasting reductions in PTSD symptoms for most patients on both clinician symptoms ratings (6‐month posttreatment effect size δ = 1.22) and self‐report measures with only three dropouts.
Thermo‐Responsive Hydrogels with Nanodomains: Rapid Shrinking of a Nanogel‐Crosslinking Hydrogel of Poly(N‐isopropyl acrylamide)
Authors: Morimoto Nobuyuki , Ohki Takafumi , Kurita Kimio , Akiyoshi Kazunari 
Published: April 2008

AbstractRapidly shrinking poly(N‐isopropyl acrylamide) (PNIPAM) hydrogels are prepared by crosslinking with self‐assembled nanogels that consist of cholesteryl‐ and methacryloyl‐substituted pullulan (CHPMA). The CHPMA nanogel (Rh = 26.4 nm) was used as a crosslinker for a hydrophilic nanodomain. Transmission electron microscopy images of the nanogel‐crosslinked PNIPAM hydrogel reveal a well‐defined nanoporous structure. The nanogel‐crosslinked PNIPAM hydrogel shows rapid shrinking based on its structure. The shrinking half‐time was ≈2 min, which is about 3 400 times faster than that of a PNIPAM hydrogel crosslinked by methylene(bisacrylamide).magnified image
Geminin is overexpressed in human pancreatic cancer and downregulated by the bioflavanoid apigenin in pancreatic cancer cell lines
Authors: Salabat Mohammad R. , Melstrom Laleh G. , Strouch Matthew J. , Ding Xian‐Zhong , Milam Benjamin M. , Ujiki Michael B. , Chen Catherine , Pelling Jill C. , Rao Sambasiva , Grippo Paul J. , McGarry Thomas J. , Bentrem David J. 
Published: April 2008

AbstractPancreatic adeniocarcinoma is among the deadliest of human cancers. Apigenin, an antitumor flavonoid, inhibits pancreatic cancer cell proliferation in vitro. Geminin is a recently identified novel protein that plays a critical role in preventing abnormal DNA replication by binding to and inhibiting the essential replication factor Cdt1. Microarray analysis identified geminin to be downregulated in pancreatic cancer cells treated with apigenin. Therefore, we investigated the effects of apigenin on geminin expression and other proteins involved in replication (Cdc6, Cdt1, and MCM7) in pancreatic cancer cell lines CD18 and S2013. Real time RT‐PCR and western blotting analysis showed that geminin expression is downregulated by apigenin at both mRNA and protein levels. Furthermore, treatment of cells with proteosome inhibitor MG132 reversed the downregulation of geminin by apigenin, supporting our hypothesis that the degradation pathway is another mechanism by which apigenin affects geminin expression. Apigenin treatment also resulted in downregulation of Cdc6 at both mRNA and protein levels. However, Cdt1 and MCM7 expression was not affected in apigenin‐treated cells. The effect of apigenin treatment on geminin promoter activity was measured by transient transfection of Hela cells with a reporter gene, demonstrating that apigenin inhibited geminin promoter activity. Geminin expression was also evaluated in human pancreatic tissue (n = 15) by immunohistochemistry and showed that geminin is overexpressed in human pancreatic cancer compared to normal adjacent pancreatic tissue. In conclusion, our studies demonstrated that geminin is overexpressed in human pancreatic cancer and downregulated by apigenin which may contribute to the antitumor effect of this natural flavonoid. © 2008 Wiley‐Liss, Inc.
A uniform optimal‐order estimate for an Eulerian‐Lagrangian discontinuous Galerkin method for transient advection–diffusion equations
Authors: Wang Kaixin 
Published: April 2008

AbstractWe prove an optimal‐order error estimate in a weighted energy norm for the Eulerian‐Lagrangian discontinuous Galerkin method for unsteady‐state advection–diffusion equations with general inflow and outflow boundary conditions. It is well‐known that these problems admit dynamic fronts with interior and boundary layers. The estimate holds uniformly with respect to the vanishing diffusion coefficient. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Adverse drug reactions reporting by physicians in Ibadan, Nigeria
Authors: Okezie Enwere O. , I. Fawole Olufunmilayo 
Published: April 2008

AbstractObjectiveTo assess knowledge, extent of reporting and factors influencing reports of adverse drug reactions (ADRs) by resident doctors.Study design and settingStudy site was the University College Hospital (UCH), Ibadan, an 850‐bed tertiary care hospital in western Nigeria. It was a cross‐sectional survey. Data were collected with a 46‐item self‐administered questionnaire from 192 clinical physicians.ResultsOlder aged doctors, senior cadre and doctors in medical faculty were 1.5 times likely to be aware of ADR reporting guidelines. General knowledge on ADR was good while 58.3% of residents knew the burden of ADRs. Most (89.5%) had observed at least one ADR but only 32% had ever reported it. Residents in medical faculty were twice more likely to report ADRs than the surgeons [OR 2.1; 95%CI 1.1, 4.1]. The commonest factors that militate against ADR reporting were lack of knowledge that reporting forms were available (70.9%) and ignorance of reporting procedure (69%).ConclusionDespite high observation and good knowledge of ADR among doctors, the rate of reporting was low. There is need for publicity of activities of the pharmacovigilance unit of the hospital. Copyright © 2008 John Wiley & Sons, Ltd.
Interfacial adsorption characteristics of ionic polymeric amphiphiles with comb‐like structures: Effect of dodecyl and poly(ethylene oxide) side chains
Authors: Chandrasekar K. , Baskar Geetha 
Published: April 2008

AbstractTwo sets of terpolymers, polymer A and polymer B consisting of almost same level of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) component at 0.635 ± 0.005 m and varying dodecyl methacrylate (DoDMAc) and monomethoxy poly(ethylene glycol) acrylate (PEGAc) components have been designed. Polymer A, consisting of less C12 component, has been shown to promote intermolecular aggregated structures wherein C12 domains exhibit compact packing characteristics. It is demonstrated that in polymer B, AMPS segments are predominantly present as ionic clusters contributing to a high pKa at about 9.50 for a low α of 0.20. From the results of interfacial adsorption estimations at air/solution and water/hexane interface, it is shown that open coil structures provided under high pH (>9.0) conditions promote efficiency of adsorption. This is shown from higher surface excess concentration (Γ) and lower interfacial area (a) estimated using Gibbs adsorption isotherm equation. For example, at water/hexane interface, polymer A exhibits Γ of 1.20 × 10−3 moles/1000 m2 at pH 3.2 and 1.97 × 10−3 moles/1000 m2 at pH 10.0. Significantly, in case of polymer B consisting of ionic clusters of AMPS, adsorption at the liquid/liquid interface is more efficient in comparison to polymer A at all pH. © 2008 Wiley Periodicals, Inc. JPolym Sci Part A: Polym Chem 46: 3257–3271, 2008
Thermomechanical and optical characteristics of stretched polyvinylidene fluoride
Authors: Chang Wen‐Yang , Fang Te‐Hua , Lin Yu‐Cheng 
Published: April 2008

AbstractThe thermomechanical and optical characteristics of polyvinylidene fluoride (PVDF) are investigated using a thermomechanical, a nanoindentation, anda photometric analyzer for flexible electronic applications. Experimental results show that thermomechanical characteristics, thermal elongation, and expansion, are greatly influenced at stretching ratios of over four in the stretching direction. Consequently, shrinking occurs because of higher cohesion at the tie chains of the amorphous regions. Additionally, there are almost uniform hardness and Young's modulus of about 0.25 ± 0.01 and 3.44 ± 0.14 GPa when the penetration depth is about 1000 nm. Unstretched PVDF films have a higher absorbance in the ultraviolet light range than stretched films do. PVDF films stretched over three times their original length have transmittance of above 90% at near infrared light. In addition, PVDF films stretched at lower temperatures show a lower transmittance because the films easily whitened during α to β phase transformations. The results provide information to optimize PVDF films for applications in flexible designs. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 949–958, 2008
The interobserver variability of digital rectal examination in a large randomized trial for the screening of prostate cancer
Authors: Gosselaar C. , Kranse R. , Roobol M.J. , Roemeling S. , Schröder F.H. 
Published: April 2008

AbstractBACKGROUNDTo analyze to what extent the percentage of suspicious digital rectal examination (DRE) findings vary between examiners and to what extent the percentage of prostate cancers (PCs) detected in men with these suspicious findings varies between examiners.METHODSIn the first screening round of the European Randomized study of Screening for PC (ERSPC) Rotterdam, 7,280 men underwent a PSA‐determination and DRE of whom 2,102 underwent prostate biopsy (biopsy indication PSA ≥ 4.0 ng/ml and/or suspicious DRE and/or TRUS). Descriptive statistics of DRE‐outcome per PSA‐range were used to determine the observer variability of six examiners. Because this analysis did not correct properly for other predictors of a suspicious DRE (PSA‐level, biopsy indication, TRUS‐outcome, prostate volume and age), a logistic regression analysis controlling for these explanatory variables was performed as well.RESULTSIn 2,102 men biopsied, 443 PCs were detected (PPV = 21%). For all PSA levels the percentage suspicious DRE varied between examiners from 4% to 28% and percentage PC detected in men with a suspicious DRE varied from 18% to 36%. Logistic regression analysis showed that three of six examiners considered DRE significantly more often abnormal than others (ORs 3.48, 2.80, 2.47, P < 0.001). For all examiners the odds to have PC was statistically significantly higher in case of a suspicious DRE (ORs 2.21–5.96, P < 0.05). This increased chance to find PC was not significantly observer‐dependent.CONCLUSIONSThree of six examiners considered DRE significantly more often suspicious than the others. However, under equal circumstances a suspicious DRE executed by each examiner increased the chance of the presence of PC similarly. Prostate 68:985–993, 2008. © 2008 Wiley‐Liss, Inc.
Influence of dielectric surface modification on growth, structure and transport properties of perylene films
Authors: Effertz Christian , Beigmohamadi Maryam , Niyamakom Phenwisa , Schulz Philip , Wuttig Matthias 
Published: April 2008

AbstractIn this study the properties of organic thin film transistors (OTFTs) based on perylene films have been investigated. To tailor the film properties, the dielectric layer on which the perylene films were deposited on was modified by different chemical treatments. Both film properties and the device efficiency have been studied employing a range of techniques including atomic force microscopy, X‐ray diffraction and a drop shape analysis for the determination of the surface free energy. A clear correlation between the adhesion energy with the dielectric surface modification is found. The change in adhesion energy influences the thin‐film growth on the modified substrate and therefore the film morphology and structure. This in turn has a profound impact on the transistors performance as the charge carrier mobility and the on‐to‐off current ratio are effected. Hence by tailoring of the dielectric surface for the growth of perylene films, the thin‐film transistor performance can be optimized. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
m ‐plane GaN/InGaN/AlInN on LiAlO2 grown by MOVPE
Authors: Behmenburg H. , Wen T. C. , Dikme Y. , Mauder C. , Khoshroo L. Rahimzadeh , Chou M. M. C. , Rzheutskii M. V. , Lutsenko E. V. , Yablonskii G. P. , Woitok J. , Kalisch H. , Jansen R. H. , Heuken M. 
Published: April 2008

AbstractWe present a study of growth and properties of m ‐plane GaN/InGaN/AlInN structures on LiAlO2 substrates grown by metal organic vapour phase epitaxy (MOVPE). A buffer structure, including an m ‐plane AlInN interlayer prior to GaN growth, has been developed. Quantum well structures on top of this buffer showed absence of polarization‐induced electric fields verified by room temperature photoluminescence (RT PL) measurements with different excitation intensities. Different samples with peak emission wavelength between 433 nm and 495 nm exhibited stable peak position even for high excitation intensities of 500 kW/cm2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron irradiation and the equilibrium of open core dislocations in gallium nitride
Authors: Hawkridge M. , Cherns D. , Liliental‐Weber Z. 
Published: April 2008

AbstractUnder electron irradiation, nanopipes in GaN are found to evolve into the so‐called bamboo structure and eventually into a chain of voids [Pailloux et al., Appl. Phys. Lett. 86, 131908 (2005)]. Here, the driving mechanism for this morphological evolution is examined using transmission and scanning transmission electron microscopy studies of undoped GaN grown by hydride vapor phase epitaxy. Irradiation at varying beam energies shows that morphological evolution occurs below the threshold for direct knock‐on damage, and that voids migrate towards the beam. It is proposed that these observations can be explained by the stimulated diffusion of point defects. In areas relatively unexposed to electrons, a survey of core character, diameter and depth into the layer suggests that a similar process occurs by post‐growth annealing, i.e. due to point defects mobile at the growth temperature. The implications of these results for understanding dislocation core structures are assessed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)