bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the fine crystalline structure of polyethylenes via annealing and thermal fractionation
Authors: Xie Yunchuan , Zhang Qian , Fan Xiaodong 
Published: June 2003

AbstractThe fine crystalline structures of two polyethylenes have been investigated with annealing and fractionation techniques via modulated differential scanning calorimetry. The molecular structure and polydispersity of both high‐density polyethylene and low‐density polyethylene have been characterized by multiple‐step annealing and successive self‐nucleation/annealing thermal fractionation methods. The effects of annealing on the crystallinity and mechanical properties and the possible mechanism of the formation of the different fine crystalline structures related to the macromolecular chain motion for the two polyethylenes have also been studied and analyzed according to detailed annealing and fractionation processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2686–2691, 2003
Synthesis and characterization of chiral side‐chain liquid‐crystalline polymer containing menthol ester
Authors: Jiang Tong‐Ying , Zhang Bao‐Yan , Tian Mei , Wang Ying 
Published: June 2003

AbstractThe synthesis of new chiral side‐chain liquid‐crystalline polysiloxanes containing p‐(allyoxy)benzoxy‐p‐chlorophenyl (ABCH) as mesogenic units and undecylenic acid menthol ester (UM) as chiral nonmesogenic units is presented. The chemical structures of monomers and polymers are confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to measure thermal properties of those polymers. Mesogenic properties are characterized by polarized optical microscope (POM), DSC, and small‐angle X‐ray diffraction. Analytic results revealed that polymers P0–P6 are thermotropic liquid‐crystalline polymers with low glass transition; Polymers P2–P6 exhibit chiral smectic liquid‐crystalline properties with marble texture, optical rotation, and a sharp reflection at low angles in X‐ray diffraction; polymers P0, P1 only exhibit smectic liquid‐crystalline properties without chirality; and P7 only exhibits chirality without liquid‐crystalline properties. All the polymers exhibit good thermal stability with temperature of 5% mass loss over 297°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2845–2851, 2003
Preparation and properties of APPSSQ‐like/polyimide hybrid composites
Authors: Hsueh Huai‐Bin , Chen Chuh‐Yung , Wang Cheng‐Chien , Chu Tzong‐Jeng 
Published: June 2003

AbstractHydrolysis and condensation proceeded to generate 3‐aminopropyl polysilsesquioxane‐like (APPSSQ‐like) particles from 3‐aminopropyl triethoxysilane. An APPSSQ‐like particle includes two domains: crosslinking SiOSi networks inside and 3‐aminopropyl groups outside the particle. The APPSSQ‐like/polyimide (APPSSQ‐like/PI) hybrid composites were prepared from a solution of poly(amic acid) (PAA, polyimide precursor) and APPSSQ‐like particles using N,N‐dimethylacetamide as a solvent. Scanning electron microscopy (SEM) showed that the APPSSQ particle sizes were about 100 nm, and there was no obvious phase separation between the APPSSQ‐like particles and the PI matrix in the fracture surfaces of the hybrid films. Owing to the highly crosslinked SiOSi networks inside the APPSSQ‐like particles, the APPSSQ‐like/PI hybrid composites possessed desired properties such as improved thermal resistance and reduced coefficients of thermal expansion (CTE). The presence of covalent bonds between the APPSSQ‐like particles and the PI molecules improved the compatibility between these two components. Thus, the tensile strength increased with the APPSSQ‐like content, and the elongation at break also slightly increased with the APPSSQ‐like content. The initial tensile and storage moduli of the APPSSQ‐like/PI hybrid composites increased with the APPSSQ‐like content, which indicates that the mechanical properties of these hybrid composites were enhanced by the incorporation of the APPSSQ‐like content in the PI matrix. Furthermore, the glass transition temperatures of these composites increased with the APPSSQ‐like content because the adhesion between the APPSSQ‐like particles and the PI molecules restricts the PI chains' mobility. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2865–2874, 2003
NKG2D engagement of colorectal cancer‐specific T cells strengthens TCR‐mediated antigen stimulation and elicits TCR independent anti‐tumor activity
Authors: Maccalli Cristina , Pende Daniela , Castelli Chiara , Mingari Maria Cristina , Robbins Paul F. , Parmiani Giorgio 
Published: June 2003

AbstractThe NKG2D receptor is expressed by human NK, γ δ T and α/β T lymphocytes and its engagement results in the stimulation of effector cells. We evaluated the role of NKG2D receptor in anti‐colorectal cancer (CRC) immune response. The cell surface expression of stress‐inducible NKG2D ligands MICA/B (MHC class I‐related chain molecules A/B) and ULBP (UL16 binding protein) by apanel of CRC lines was evaluated by flow cytometry. MICA and ULBP2/3 were widely expressed by the analyzed lines, with a minority of them being also ULBP‐1+, whereas MICB was undetectable.CD8+ and CD4+ HLA‐restricted anti‐tumor T cell clones of a CRC patient were used to evaluate whether NKG2D engagement could mediate tumor recognition. Three out of four CD8+ T cell clones recognized the autologous tumor with a marginal NKG2D engagement, a finding that was correlated with the weak expression of NKG2D ligands by the autologous tumor. On the contrary, NKG2D triggering of these CD8+ T cell clones induced recognition of allogeneic CRC lines showing high expression of MICA and ULBP. A costimulatory role of NKG2D was observed with one CD4+/NKG2D+ T cell clone when stimulated by tumors sharing the HLA class II alleles and expressing NKG2D ligands. Taken together these data indicate that the engagement of NKG2D, depending on the expression of its ligands by target cells, can influence the pattern of anti‐tumor reactivity by T lymphocytes.
Suitability of oligonucleotide‐mediated cystic fibrosis gene repair in airway epithelial cells
Authors: de Semir David , Nadal Marga , González Juan R. , Larriba Sara , Avinyó Anna , Nunes Virginia , Casals Teresa , Estivill Xavier , Aran Josep M. 
Published: June 2003

AbstractBackgroundNon‐viral vector‐mediated targeted gene repair could become a useful alternative to classical gene addition strategies. The methodology guarantees a physiologically regulated and persistent expression of the repaired gene, with reported gene conversion and phenotypic correction efficiencies approaching 40–50% in some in vitro and in vivo models of disease. This is particularly important for cystic fibrosis (CF) because of its complex pathophysiology and the cellular heterogeneity of the cystic fibrosis transmembrane conductance regulator (CFTR) gene expression and function in the lung.MethodsA cell‐free biochemical assay was applied to assess the ability of CF airway epithelial cells to support chimeraplast‐mediated repair. In addition, a methodology allowing the relative quantification of the percentage of W1282X mutation repair in a heterozygous background using the PCR/oligonucleotide ligation assay (PCR/OLA) was developed. The performance of different chimeraplast and short single‐stranded oligonucleotide structures delivered by non‐viral vectors and electroporation was evaluated.ResultsChimeraplast‐mediated repair competency was corroborated in CF airway epithelial cells. However, their repair activity was about 5‐fold lower than that found in liver cells. Moreover, regardless of the corrector oligonucleotide structure applied to our CF bronchial epithelial cells, of compound heterozygous genotype (F508del/W1282X), the percentage of their resulting wild‐type allele in the W1282X (exon 20) locus of the CFTR gene was not significantly different from that of the control untreated cells by our PCR/OLA assay (confidence interval at 95% ± 4 allele wild‐type).ConclusionsOligonucleotide‐mediated CFTR gene repair is an inefficient process in CF airway epithelial cells. Further improvements in oligonucleotide structure, nuclear delivery and/or the capability for mismatch repair stimulation will be necessary to achieve therapeutic levels of mutation correction in these cells. Copyright © 2003 John Wiley & Sons, Ltd.
A tetracycline‐regulated adenoviral expression system for in vivo delivery of transgenes to lung and liver
Authors: Tietge Uwe J. F. , Kozarsky Karen F. , Donahee Mary H. , Rader Daniel J. 
Published: June 2003

AbstractBackgroundRecombinant adenoviruses are an established tool for somatic gene transfer to multiple cell types in animals as well as in tissue culture. However, generation of adenoviruses expressing transgenes that are potentially toxic to the host cell line represents a practical problem. The aim of this study was to construct an adenoviral expression system that prevents transgene expression during the generation and propagation of the virus, and allows efficient gene transfer to lung and liver, major target organs of gene therapy.MethodsUsing the tet‐off system we constructed tetracycline (tet) regulatable recombinant adenoviruses expressing the marker gene LacZ (Adtet‐off.LacZ) as well as a secretory protein, human group IIA secretory phospholipase A2 (Adtet‐off.hsPLA2). Expression (Western blot, activity assay) was tested in vitro (HeLa cells), and in vivo by gene transfer to lung and liver.ResultsWithout addition of tetracycline we demonstrated expression of LacZ (Adtet‐off.LacZ) and sPLA2 (Adtet‐off.hsPLA2) in HeLa cells. Providing additional tet‐transactivator (tTA) protein either by stable transfection or coinfection with a tTA‐expressing adenovirus resulted in a further increase of LacZ and sPLA2 expression. Transgene expression in vitro was eliminated by the addition of tetracycline to the culture medium. Adtet‐off.LacZ and Adtet‐off.hsPLA2 allowed successful gene transfer in vivo to lung and liver. While the expression was highly efficient within the lungs, however, additional tTA was necessary to achieve high‐level expression within liver.ConclusionsTet‐regulatable adenoviral expression systems may facilitate the construction of recombinant adenoviruses encoding potentially toxic transgenes and permit regulated transgene expression. Copyright © 2003 John Wiley & Sons, Ltd.
Adenoviral VEGF‐A gene transfer induces angiogenesis and promotes bone formation in healing osseous tissues
Authors: Tarkka Tatu , Sipola Annina , Jämsä Timo , Soini Ylermi , Ylä‐Herttuala Seppo , Tuukkanen Juha , Hautala Timo 
Published: June 2003

AbstractBackgroundVascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. VEGF has been safely and efficiently applied to stimulate neovascularization in ischemic tissues in atherosclerotic patients. VEGF has an important role in bone repair by promoting angiogenesis and by stimulating major skeletal cell populations, chondrocytes, osteoblasts and osteoclasts.MethodsWe studied the effect of VEGF‐A on the recovery of bone drilling defects in rat femur delivered with first‐generation adenoviral vector. The virus was injected into the muscle layer surrounding the bone defect made by drilling and the healing was followed for 1, 2, and 4 weeks.ResultsThe VEGF effect was first demonstrated with an increased number of FVIII‐related antigen‐positive blood vessels in the defect area 1 week after the procedure. The proportional area of remaining reparative tissue was significantly reduced in the VEGF‐treated animals 2 weeks after the injury suggesting favorable effect on bone healing. Increased periosteal cartilage was seen at the early phases of healing suggesting endochondral ossification. VEGF overexpression, however, completed the endochondral phase earlier compared with the control condition. Bone mineral content was enhanced in the VEGF‐treated femurs measured with peripheral quantitative computed tomography at a 2‐week time point.ConclusionsOur data confirm the important role of VEGF in bone healing. We show for the first time that adenoviral VEGF‐A gene transfer may modify bone defect healing in a rodent model. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of jump training on passive mechanical stress and stiffness in rabbit skeletal muscle: role of collagen
Authors: Ducomps C. , Mauriège P. , Darche B. , Combes S. , Lebas F. , Doutreloux J. P. 
Published: June 2003

AbstractAims:  This study evaluated the effect of a 15‐week jump training period on mechanical parameters and collagen concentration of different muscle types in rabbits, at 50, 90 and 140 days of age.Methods:  Trained (T) animals were made to jump over obstacles in order to get food and water. The height of the obstacle was increased according to the animal's age. Control (C) animals were sedentary. Mechanical parameters (force, stress, stiffness) and collagen concentration were measured in Extensor Digitorum Longus (EDL), Rectus Femoris (RF), Semimembranosus Proprius (SMP) and Psoas Major (PSOAS).Results:  Both EDL and RF collagen concentrations and passive mechanical parameters increased between 50 and 140 days of age (P < 0.001), whereas SMP and PSOAS collagen concentrations decreased (P < 0.001). Soluble collagen concentration decreased similarly with age in all muscles and groups. Exercise training at 140 days induced a significant increase in force (EDL 20.4% and RF 15.3%, 0.01 < P < 0.05), stress (EDL 26.8% and RF 22.6%, P < 0.001), and stiffness (EDL 13.2% and RF 16%, 0.001 < P < 0.05) with a greater collagen concentration (EDL 16.1% and RF 19.1%, 0.001 < P < 0.05). Finally, stiffness and stress are well correlated with collagen concentration in EDL and RF muscles at 140 days (0.74 < r < 0.84, P < 0.05).Conclusion:  These results suggest that jump training can increase muscle capabilities of strength and stiffness in fast‐twitch mixed muscles with pennate architecture (EDL, RF). This increase is essentially mediated by a rise in cross‐linked collagen fraction, coupled with a relative decrease in soluble collagen. The collagen covalent cross‐links improve resistance and stability in force transmission processes during stretching.
Endogenous NO does not regulate baseline pulmonary pressure, but reduces acute pulmonary hypertension in dogs
Authors: Sander M. , Welling K. ‐L. K. , Ravn J. B. , Boberg B. , Amtorp O. 
Published: June 2003

AbstractIt has remained unclear whether endogenous production of nitric oxide (NO) plays an important role in the regulation of physiologically normal pulmonary pressures. Severe alveolar hypoxia is accompanied by decreased pulmonary NO production, which could contribute to the development of hypoxic pulmonary hypertension. On the other hand, pharmacological NO inhibition further augments this hypertensive response.Aims:  The aims of the present study were to test: (a) whether NO contributes importantly in the maintenance of baseline pulmonary pressure; and (b) to which degree NO is involved in the pulmonary haemodynamic adjustments to alveolar hypoxia.Methods:  In anaesthetized dogs (n = 37), the systemic and pulmonary haemodynamic effects of the NO synthase inhibitor, Nω‐nitro‐l‐arginine methyl ester (l‐NAME, 20 mg kg−1) and substrate, l‐arginine (200–500 mg kg−1), were determined at baseline and during alveolar hypoxia. Constant blood flows were accomplished by biventricular bypass, and systemic normoxaemia was maintained by extracorporeal oxygenation.Results:  The primary findings were: (a) l‐NAME failed to increase baseline mean pulmonary arterial pressure (10.1 ± 0.7 vs. 10.5 ± 0.5 mmHg, P = ns), despite effective NO synthase inhibition as evidenced by robust increases in systemic arterial pressures; (b) l‐NAME augmented the pulmonary hypertensive response to alveolar hypoxia (10.2 ± 0.7 to 19.5 ± 1.7 with l‐NAME vs. 9.9 ± 1.1 to 15.5 ± 1.0 mmHg without l‐NAME, P < 0.05); and (c) l‐arginine failed to decrease baseline or elevated pulmonary pressures. Instead, prolonged l‐arginine caused increases in pulmonary pressure.Conclusion:  These findings suggest that NO plays no significant role in the tonic physiological control of pulmonary pressure, but endogenous NO becomes an important vasodilatory modulator during elevated pulmonary pressure.
Is antimicrobial susceptibility testing necessary before second‐line treatment for Helicobacter pylori infection?
Authors: Miwa H. , Nagahara A. , Kurosawa A. , Ohkusa T. , Ohkura R. , Hojo M. , Enomoto N. , Sato N. 
Published: June 2003

SummaryBackground:  An antimicrobial susceptibility test for Helicobacter pylori before second‐line treatment is often performed, although whether the test is truly necessary remains unknown.Patients and methods:  Eighty‐two patients with H. pylori infection for whom first‐line treatment with a 1‐week proton pump inhibitor/amoxicillin–clarithromycin (AC) regimen had failed were randomly assigned to two groups: those having or not having the susceptibility test before re‐treatment. The cure rates for these two groups were compared.Results:  Five of the 82 patients were excluded from the analysis. For 38 patients in the susceptibility‐test group, we used what we considered the best regimen based on susceptibility testing: 10 patients [no resistance to clarithromycin (CAM)] received the lansoprazole–amoxicillin–clarithromycin regimen, 22 patients [19 CAM resistant, metronidazole (MNZ) susceptible; three failure of culture] were given the lansoprazole‐amoxicillin‐metronidazole (LAM) regimen, and six patients (both MNZ and CAM resistant) received dual therapy with omeprazole (OPZ) and amoxicillin (AMOX) in which the OPZ dose was determined by the CYP2C19 gene polymorphism. For 39 patients in the group with no susceptibility testing, LAM regimens were prescribed. The intention‐to‐treat (ITT)‐based cure rates in the groups with and without susceptibility testing were 81.6% (95% confidence interval; 66–92%) and 92.4% (79–98%), respectively, and there was no significant difference between these two groups.Conclusion:  Susceptibility testing is not necessarily required before second‐line therapy if the first‐line treatment has been performed using proton pump inhibitor/AC regimens.
Additional molecular bases of the clinically important p blood group phenotype
Authors: Hellberg Åsa , Steffensen Rudi , Yahalom Vered , Sojka Birgitta Nilsson , Heier Hans Erik , Levene Cyril , Poole Joyce , Olsson Martin L. 
Published: June 2003

BACKGROUND: The purpose of this study was to explore the molecular basis of the p phenotype by analysis of the recently cloned 4‐α‐galactosyltransferase gene responsible for synthesis of Pk (Gb3) antigen.STUDY DESIGN AND METHODS: Forty samples from individuals of eight different nationalities were investigated by serologic methods and DNA sequencing of the Pk gene.RESULTS: Ten different Pk‐null alleles, of which 6 are novel, were encountered. The 29 Swedes were homozygous for M183K or G187D, with the former as the predominant allele. Three Israelis were homozygous for a single‐nucleotide deletion at codon 219 that shifts and truncates the reading frame by 5 amino acids. Two Italians were homozygous for a triplet deletion causing F81del, while an English donor was heterozygous for F81del but also carried another allele with a combined deletion and insertion. A Pole was heterozygous for alleles with either a single‐base deletion at codon 257 or a mutation causing S97L. A Norwegian person and a Japanese person were homozygous for single‐base insertions causing a premature stop at codon 282 or extension of the protein by 92 residues, respectively. In 2 samples no mutations were detected.CONCLUSION: The genetic heterogeneity underlying the p phenotype is further emphasized by this study. To date, 11 p‐specific mutations have been found in 14 distinct alleles.
The importance of antibodies against low‐incidence RBC antigens in complete and abbreviated cross‐matching
Authors: Schonewille Henk , Zijl Annette M. van , Wijermans Pierre W. 
Published: June 2003

BACKGROUND: It is common practice to perform an antiglobulin cross‐match only when unexpected RBC alloantibodies are present, to detect antibodies against additional RBC antigens. In this study, the incidence of unexpected antibodies to low‐incidence antigens (Ab‐LIA) over a period of 23 years was investigated.STUDY DESIGN AND METHODS: Records of RBC antibodies and the accompanying transfusion history from 1978 through 2000 was retrospectively examined. Complete cross‐matches were performed for all RBC transfusions before 1991. As of 1991, the type‐and‐screen policy was applied. To study the incidence of anti‐Wra, a prospective study was conducted on sera from 462 patients sent to the transfusion laboratory and 486 blood donors.RESULTS: The records of 1795 patients containing 2257 RBC antibodies were examined. In 89 patients, a total of 94 Ab‐LIAs was found. Anti‐Wra was the most frequently encountered Ab‐LIA. Thirty‐nine patients had Ab‐LIA in combination with other antibodies, 20 of which were autoantibodies. Eighty percent of these Ab‐LIA were found at the first positive antibody screening test. Fifty‐one solitary Ab‐LIA were found in 50 patients, 37 during antibody screening tests, and 14 after positive complete cross‐matches conducted before 1991. After an RBC antibody was detected, 664 patients received a total of 7792 RBC transfusions. Since the introduction of the type‐and‐screen policy, only one anti‐Wra has been discovered during complete cross‐matching. No transfusion reactions due to Ab‐LIA were reported during the study period. In the prospective study, 12.3 percent of patients and 4.3 percent of blood donors had anti‐Wra.CONCLUSIONS: Although Ab‐LIAs are found coincidentally in the sera of only 2 to 3 percent of patients with other RBC antibodies, they are formed often. Because we found no difference in serologic incompatibility, due to Ab‐LIAs, between patients with and without other blood group antibodies, we conclude that blood can be transfused safely to patients without performing a complete cross‐match.
Forecasting for a Remote Island: A Class Exercise
Authors: Riordan Allen J. 
Published: June 2003

Students enrolled in a satellite meteorology course at North Carolina State University, Raleigh, recently had an unusual opportunity to apply their forecast skills to predict wind and weather conditions for a remote site in the Southern Hemisphere. For about 40 days starting in early February 2001, students used satellite and model guidance to develop forecasts to support a research team stationed on Bouvet Island (54°26′S, 3°24′E). Internet products together with current output from NCEP's Aviation (AVN) model supported the activity. Wind forecasts were of particular interest to the Bouvet team because violent winds often developed unexpectedly and posed a safety hazard.
Results were encouraging in that 24-h wind speed forecasts showed reasonable reliability over a wide range of wind speeds. Forecasts for 48 h showed only marginal skill, however. Two critical events were well forecasted—the major February storm with wind speeds of over 120 kt and a brief calm period following several days of strong winds in early March. The latter forecast proved instrumental in recovering the research team.