bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevation of tricuspid regurgitant jet velocity, a marker for pulmonary hypertension in children with sickle cell disease
Authors: Ambrusko Steven J. , Gunawardena Sriya , Sakara Allison , Windsor Beth , Lanford Lizabeth , Michelson Peter , Krishnamurti Lakshmanan 
Published: February 2006

AbstractBackgroundPulmonary hypertension (PHTN) is a potentially life‐threatening complication, detected by echocardiographic evidence of elevated tricuspid regurgitant velocity (TRV). This condition has been described in adults with sickle cell disease (SCD) and other hemolytic disorders; however, there is little information on the occurrence of this condition in pediatric patients.MethodsRecords for pediatric SCD patients were retrospectively reviewed to determine clinical characteristics and co‐morbidities of patients with elevated TRV on echocardiograms obtained under steady state conditions as an outpatient. Correlation of TRV ≥2.5 m/sec with age, sex, type of SCD, number of outpatient echocardiograms per patient, episodes of vasoocclusive crisis (VOC) and acute chest syndrome (ACS), mean hemoglobin and reticulocyte count, asthma, obstructive sleep apnea, cerebrovascular disease (CVD), and hydroxyurea therapy was determined.ResultsOf 224 SCD patients, 44 had outpatient echocardiographic measurement of TRV. Patients (11 of 44) (26.2%) with TRV ≥2.5 m/sec were compared to 31 patients without elevated TRV. Significant differences were noted for percent with HbSS disease (P = 0.041), CVD (P = 0.021), hemoglobin (P = 0.003), % reticulocytes (P = 0.037), and number of echocardiograms performed (P < 0.001). No significant differences were observed for gender, age, asthma, or frequency of VOC and ACS.ConclusionsElevated TRV, a surrogate marker for PHTN, occurs in children with SCD and is associated with low hemoglobin, elevated reticulocyte count, and cerebral vasculopathy. Appropriate screening by echocardiography can lead to detection and treatment that may reduce TRV and potentially reverse the disease process, prevent the increased morbidity and mortality associated with PHTN. © 2006 Wiley‐Liss, Inc.
Curing of composite components by ultraviolet radiation: A review
Authors: Endruweit A. , Johnson M. S. , Long A. C. 
Published: February 2006

AbstractCuring of polymer matrices by ultraviolet (UV) irradiation can be applied to a variety of processes in the production of composite components, as long as the component can be directly irradiated. Wet lay‐up techniques, vacuum infusion type processes with UV‐transparent membranes, filament winding, and prepreg processes have been adapted to UV curing. Unlike in thermal curing, the curing time is in the order of magnitude of minutes rather than hours, which means a significant reduction in cycle time. The radiation can be generated by a variety of sources suitable for various specific applications and different curing strategies. The most frequently used radiation sources are mercury arc lamps. Because of the absorption of radiation passing through matter, the thickness of laminates for efficient application of UV curing is limited. The curing mechanism is either radical polymerization for acrylate‐based resins or cationic polymerization for epoxies and vinyl ethers. The properties of the UV‐cured polymer matrix are determined by the cross‐linking density. This depends on the type and concentration of the photoinitiator and of the (optional) diluents, the intensity and the duration of the irradiation, and the temperature at which the curing process takes place. POLYM. COMPOS., 27:119–128, 2006. © 2006 Society of Plastics Engineers.
Accelerated fatigue properties of unidirectional carbon/epoxy composite materials
Authors: Chen Hsing‐Sung , Hwang Shun‐Fa , Chen Hsing‐Sung 
Published: February 2006

AbstractIt has been confirmed that polymer matrix composites possess viscoelastic behavior. This means that one could accelerate the fatigue testing by changing the stress amplitude, frequency, or temperature. This study is to investigate the accelerated fatigue properties, which are resulted from the viscoelastic behavior, of carbon/epoxy composites and to predict their fatigue life. For this purpose, a series of fatigue tests of unidirectional specimens are conducted at room temperature under different stress ratios and stress frequencies. A group of sigmoid S‐N curves, which are suitable for the whole fatigue life, and the corresponding parameters are developed for different cyclic loading conditions. A transformation method, which can transform a reference S‐N curve to the corresponding S‐N curve of the assigned fatigue conditions, is established by the parameters. And this S‐N curve can be utilized to predict the fatigue life of the composite at the assigned stress ratio or stress frequency. The comparison between the linear and sigmoid S‐N curves is also carried out to show the advantages of the latter model in the whole fatigue life. POLYM. COMPOS., 27:138–146, 2006. © 2006 Society of Plastics Engineers
Characterization of polymeric biocomposite based on poly(vinyl alcohol) and poly(vinyl pyrrolidone)
Authors: Sedlařík Vladimír , Saha Nabanita , Kuřitka Ivo , Sáha Petr 
Published: February 2006

AbstractBiocompatible and easily available materials from dairy production waste were used for modification of water‐soluble polymeric blends of Poly(vinyl alcohol) (PVA) and Poly(vinyl pyrrolidone) (PVP). The resulting biocomposites of PVA/PVP with various concentrations of lactose (L) or calcium lactate (CL) (0, 5, 15, 25, 35 wt%) were prepared by using a solvent cast technique and then characterized by optical microscopy, tensile test, water content determination, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy equipped by attenuated total reflectance device, and also tested for biodegradability. The films were transparent with a smooth surface. The results confirm that L and CL work as fillers in polymeric matrix. The tensile investigations showed enhanced Young's modulus (E) and tensile strength for low‐filled of composite materials (up to 5 wt% L and 15 wt% CL). The biodegradation test in aquatic conditions revealed improved biodegradability of modified blends. Both L and CL seem to be suitable for the modification of polymers, which can be convenient from economical and environmental point of view. POLYM. COMPOS., 27:147–152, 2006. © 2006 Society of Plastics Engineers.
Design and performance analysis of a self‐regulating melt pressure valve
Authors: Kazmer David , Gupta Dheeraj , Munavalli Mahesh , Kudchadkar Vijay , Nageri Ranjan 
Published: February 2006

AbstractNet shape manufacturing of plastic products through injection molding, extrusion, and other polymer processing methods has been limited by a lack of observability and controllability of the state of the polymer melt. A self‐regulating valve is developed and validated that regulates the output melt pressure in proportion to an input control force. The valve relies on a valve pin that adjusts the juncture loss to balance the control force with the force exerted by the melt pressure on an exposed surface of the valve pin. Since the valve pin position is adjusted in accordance to natural laws, an open loop system design is feasible without need of any instrumentation or control system for closed loop feedback control. The design is analyzed using a three‐dimensional flow analysis that utilizes independent shear and elongational viscosities for the polymer melt. Pressure drops and shear stresses through the valve are analyzed to estimate the steady state error in the output pressure when the valve pin is controlled in an open loop mode (i.e. without melt pressure feedback). Guidelines for the valve design are provided to achieve a reasonable trade‐off between flow and structural requirements. Finally, experimental validation indicates an excellent level of response and consistency given the simplicity of the design. POLYM. ENG. SCI. 46:549–557, 2006. © 2006 Society of Plastics Engineers
Nonisothermal comprehensive 3D analysis of polymer melt flow in a coat‐hanger die
Authors: Wu Tingqi , Jiang Bo , Xu Shuhua , Bi Chao 
Published: February 2006

AbstractThe nonisothermal flow of Carreau fluid in a coat‐hanger die is studied. A general three‐dimensional finite volume code is developed for the purpose of flow analysis. The isobars, the isotherms, and the velocity distribution are obtained. Simulation results illustrated that the highest temperature occurred by the center of manifold, rather than the die‐lip region because of the combined effects of high shear rate and poor heat conduction, which is important for processing those heat‐sensitive materials. In the regions where die gap is relatively small, the wall temperature plays a key role in deciding temperature distribution in the melt. The validity of simulation results is verified experimentally. POLYM. ENG. SCI., 46:406–415, 2006. © 2006 Society of Plastics Engineers.
Manufacturing and foaming of high melt viscosity of polypropylene by using electron beam radiation technology
Authors: Han Do‐Hung , Jang Jae‐Hyuk , Kim Hye‐Young , Kim Byung‐Nam , Shin Boo‐Young 
Published: February 2006

AbstractThe high melt viscosity of polypropylene was studied by grafting bifunctional monomers, 1,6‐hexanediol diacrylate (HDDA) and tripropylene glycol diacrylate (TPGDA), onto homopolypropylene (HPP) and random ter‐polypropylene (RTPP) under electron‐beam irradiation. Creation of the high‐melt‐viscosity polypropylene was possible at low radiation dosage and low monomer content, under a prohibition of both radiation degradation and homopolymerization. TPGDA monomer was more effective in increasing the melt viscosity of HPP compared with RTPP, whereas HDDA monomer was more effective for enhancing the melt viscosity of RTPP. Such different effects of monomers on melt viscosity may arise from different monomer structures, namely, TPGDA has additional three methyl groups, but HDDA has no methyl groups. Electron‐beam radiation technology, on an increase of the melt viscosity, was much more effective in HPP than RTPP, when compared with virgin polymers. Modified RTPP and HPP with high melt viscosity were capable of foaming with numerous fine cells, of which the modified HPP with 1.5 mmol TPGDA and 0.5 kGy could create more spherical foam cells and its bending strength was 1.5 times more than that of the foamed RTPP. POLYM. ENG. SCI., 46:431–437, 2006. © 2006 Society of Plastics Engineers.
Finite strain 3D thermoviscoelastic constitutive model for shape memory polymers
Authors: Diani Julie , Liu Yiping , Gall Ken 
Published: February 2006

AbstractA 3D thermoviscoelastic model is proposed to represent the thermomechanical behavior of shape memory polymers. The model is based on a physical understanding of the material behavior and a mechanical interpretation of the stress–strain–temperature changes observed during thermomechanical loading. The model is thermodynamically motivated and is formulated in a finite strain framework in order to account for large strain deformations. Model predictions capture critical features of shape memory polymer deformation and, in some cases, provide very favorable comparisons with experimental results. POLYM. ENG. SCI. 46:486–492, 2006. © 2006 Society of Plastics Engineers.
Comparative analysis of radical‐mediated polyethylene modifications: Vinyltriethoxysilane versus mercaptopropyltriethoxysilane addition
Authors: Sengupta Saurav S. , Parent J. Scott 
Published: February 2006

AbstractThe efficiency and selectivity of two approaches for introducing alkoxysilane functionality to polyethylene (PE) are examined along with the moisture‐curing performance of the resulting products. Although the peroxide‐initiated grafting of vinyltriethoxysilane to PE is accompanied by undesirable crosslinking, comparable silane contents can be introduced without affecting the melt viscosity through the addition of mercaptopropyltriethoxysilane (MPTES) to the unsaturation within the polymer. Rapid hydrogen atom donation by thiols underlies this unique selectivity for grafting versus molecular weight alteration, and gives rise to a remarkable tolerance of MPTES additions to phenolic antioxidants. Direct comparisons of the moisture‐curing efficiencies provided by the two functionalization techniques reveal few significant differences in crosslink yields or composition distributions. POLYM. ENG. SCI., 46:480–485, 2006. © 2006 Society of Plastics Engineers.
Synthesis of a novel hexaarylbiimidazole with ether groups and characterization of its photoinitiation properties for acrylate derivatives
Authors: Shi Yongtao , Yin Jie , Kaji Makoto , Yori Hanako 
Published: February 2006

AbstractA novel photoinitiator 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetra‐[3‐(2‐hydroxylmethyl‐2‐triethylene glycol monoethylene ether‐ethane‐1‐oxy)‐phenyl]‐1,2′‐biimidazole (BCTE‐HABI) was synthesized from 3,3′‐dimethoxy benzoin. Ultraviolet spectra, fluorescence spectra, ESR, photodilatometer, and photo‐DSC measurements indicate that its photoinitiating activity for acrylate derivatives is better than 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetraphenyl‐1,2′‐biimidazole (o‐Cl‐HABI), which is one of the most widely studied and used derivatives of HABI. POLYM. ENG. SCI., 46:474–479, 2006. © 2006 Society of Plastics Engineers.
Rheology of wood plastics melt, part 2: Effects of lubricating systems in HDPE/maple composites
Authors: Li T. Q. , Wolcott M. P. 
Published: February 2006

AbstractRheology of HDPE/maple formulations with two common lubricating systems was studied with the capillary rheometry and the small‐amplitude oscillatory shear experiments. Shear and extensional flow data in the capillary dies revealed different lubricating roles of the additives. Small‐amplitude oscillatory tests using a rotational parallel plate rheometer were performed to further investigate the effects of additives. The ester‐type lubricant was found to both enhance maple filler dispersion and promote excellent external lubrication. The zinc stearate‐N,N′‐ethylene bis‐stearamide lubricating system, however, was shown to bear the potential of causing certain adverse effects and its role could not be fully illustrated with the capillary rheometry and the oscillatory tests based on linear viscoelasticity assumptions. Synergistic and simple rule‐of‐mixture effects were identified for different lubricating systems. POLYM. ENG. SCI., 46:464–473, 2006. © 2006 Society of Plastics Engineers.
A study of the effects of postcure treatments on polyester–melamine coating matrices
Authors: Gamage N.J.W. , Hill D.J.T. , Pomery P.J. , Lukey C. A. 
Published: February 2006

AbstractThe effect of postcure high energy (γ), ultraviolet (UV) and thermal treatment on the properties of polyester–melamine clearcoats of a range of compositions has been investigated. Two initial cure conditions were used, of which one was “optimally” cured and the other under‐cured. It was found that postcure treatments, particularly γ and UV, led to coatings of similar mechanical and thermal properties irrespective of initial cure, although the change in properties on postcure treatment was greater for the under‐cured samples. The results were interpreted in terms of the effect of the treatments on the structure of the crosslinked matrices. The study suggests the possibility of the development of a dual‐cure process for polyester–melamines, whereby cure optimization and property improvement can be achieved. This could also be used to “correct” for small variations in thermal cure levels brought about by adventitious on‐line fluctuations in cure oven conditions. POLYM. ENG. SCI. 46:532–539, 2006. © 2006 Society of Plastics Engineers
Proteomic analysis of Candida albicans yeast and hyphal cell wall and associated proteins
Authors: Ebanks Roger O. , Chisholm Kenneth , McKinnon Stewart , Whiteway Malcolm , Pinto Devanand M. 
Published: February 2006

AbstractCandida albicans is an important human pathogen that causes systemic infections, predominantly among populations with weakened immune systems. The morphological transition from the yeast to the hyphal state is one of the key factors in C. albicans pathogenesis. Owing to their location at the host–pathogen interface, the cell wall and associated proteins are of interest, especially with respect to the yeast to hyphal transition. This study entailed the proteomic analysis of differentially regulated proteins involved in this transition. The protein profiles of C. albicans DTT/SDS‐extractible proteins and the cyanogen bromide (CNBr)/trypsin‐extractable proteins of a cell wall‐enriched fraction from yeast and hyphae were compared. In total, 107 spots were identified from the DTT/SDS‐extractible cell wall‐enriched fraction, corresponding to 82 unique proteins. Of these DTT/SDS‐extractible proteins, 14 proteins were upregulated and 10 were downregulated in response to hyphal induction. Approximately 6–9% of total cell wall‐protein‐enriched fraction was found to be resistant to DTT/SDS extraction. Analysis of the DTT/SDS‐resistant fraction using a CNBr/trypsin extraction resulted in the identification of 29 proteins. Of these, 17 were identified only in the hyphae, four were identified only in the yeast, and eight were identified in both the yeast and hyphae.
Overexpression and elevated serum levels of phosphoglycerate kinase 1 in pancreatic ductal adenocarcinoma
Authors: Hwang Tsann‐Long , Liang Ying , Chien Kuan‐Yi , Yu Jau‐Song 
Published: February 2006

AbstractPancreatic ductal adenocarcinoma (PDAC) is a common malignancy with a very low 5‐year survival rate. Currently, there are no valid markers for early detection and targets for therapy. Here, we used 2‐DE to analyze the protein profiles of eight PDAC specimens and paired adjacent nontumor tissues. MS was used to identify 15 protein spots that were found to be overexpressed in PDAC tissues versus adjacent controls. One of them was identified as phosphoglycerate kinase (PGK) 1, a secretable glycolytic enzyme known to participate in angiogenesis. Immunohistochemical analysis of 63 PDAC specimens revealed moderate to strong expression of PGK1 in >70% of the tumors. Further Western blotting analysis of cells from tumor and adjacent nontumor tissues obtained by laser capture microdissection confirmed the enhanced expression of PGK1 in tumor cells. Furthermore, the serum levels of PGK1 were significantly higher in PDAC patients (n = 21) than in the control group (n = 25) (p < 0.005), as determined by ELISA. These observations indicate that protein profile analysis using a combination of 2‐DE and MS provides an effective strategy for identifying biomarkers that may have diagnostic potential for PDAC, and identify PGK1 as a potential biomarker and/or therapeutic target for PDAC.
Thermal Damage on LX‐04 Mock Material and Gas Permeability Assessment
Authors: Hsu Peter C. , DeHaven Martin , McClelland Matthew , Maienschein Jon L. 
Published: February 2006

AbstractRM‐04‐BR, a mock material for the plastic‐bonded HMX‐based explosive LX‐04, is characterized after being thermally damaged at 140 °C and 190 °C. We measured the following material properties before and after the thermal experiments: sample volume, density, sound speed, and gas permeability in the material. Thermal treatment of the mock material leads to de‐coloring and insignificant weight loss. The sample expanded, resulting in density reductions of 1.0% to 2.5% at 140 °C and 190 °C, respectively. Permeability in the mock samples was found to increase from 10−16 to 10−15 m2, as the porosity increased. The permeability measurements are well represented by the Blake‐Kozeny equation for laminar flow through porous media. The results are similar to the gas permeability in PBX‐9501 obtained by other researchers [1, 2].
Nanostructured Energetic Composites of CL‐20 and Binders Synthesized by Sol Gel Methods
Authors: Li Jun , Brill Thomas B. 
Published: February 2006

AbstractMonolithic energetic gels were prepared in acetone by separately cross‐linking the single precursors, glycidyl azide polyol (GAP polyol polyol), nitrocellulose (NC, 12% N), and tris(hydroxymethyl)nitromethane (THMNM) and the mixed precursors (GAP polyol+NC) and (GAP polyol+THMNM) with hexamethylene diisocyanate (HDI). THMNM functions as a chain extender. The synthesis conditions were optimized according to precursor mass ratio, cross‐linking agent, solvent, catalyst concentration, and containers with various surface‐to‐volume ratios. The concentrations of reactants and cure catalyst are the most important factors. The composite energetic materials with a high degree of homogeneity were synthesized by trapping hexanitrohexazaisowurtzitane (CL‐20) on the nano scale in the energetic polymer gels using sol gel processing with a modified freeze‐drying procedure. Loadings up to 85%, 93%, and 90% by weight of CL‐20 yielded, respectively, monolithic gels for GAP/HDI, NC/HDI, and THMNM/HDI. 90% CL‐20 can be loaded into gels of the mixed precursors of (GAP polyol+NC) and (GAP polyol+THMNM). The energetic gels and composites were characterized using FT‐IR spectroscopy, DSC, SEM, and sensitivity to drop weight impact. The sensitivity of CL‐20 is reduced in the energetic nanocomposites.
A simple clustering algorithm can be accurate enough for use in calculations of pKs in macromolecules
Authors: Myers Jonathan , Grothaus Greg , Narayanan Shivaram , Onufriev Alexey 
Published: February 2006

AbstractStructure and function of macromolecules depend critically on the ionization states of their acidic and basic groups. Most current structure‐based theoretical methods that predict pK of ionizable groups in macromolecules include, as one of the key steps, a computation of the partition sum (Boltzmann average) over all possible protonation microstates. As the number of these microstates depends exponentially on the number of ionizable groups present in the molecule, direct computation of the sum is not realistically feasible for many typical proteins that may have tens or even hundreds of ionizable groups. We have tested a simple and robust approximate algorithm for computing these partition sums for macromolecules. The method subdivides the interacting sites into independent clusters, based upon the strength of site–site electrostatic interaction. The resulting partition function is factorizable into computationally manageable components. Two variants of the approach are presented and validated on a representative test set of 602 proteins, by comparing the pK1/2 values computed by the proposed method with those obtained by the standard Monte Carlo approach used as a reference. With 95% confidence, the relative error introduced by the more accurate of the two methods is less than 0.25 pK units. The algorithms are one to two orders of magnitude faster than the Monte Carlo method, with the typical settings. A graphical representation is introduced that visualizes the clusters of strong site–site interactions in the context of the three‐dimensional (3D) structure of the macromolecule, facilitating identification of functionally important clusters of ionizable groups; the approach is exemplified on two proteins, bacteriorhodopsin and myoglobin. Proteins 2006. © 2006 Wiley‐Liss, Inc.