bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase behavior and crystallization of a poly(ethylene oxide)/cellulose acetate butyrate blend
Authors: Park Min Soo , Kim Jin Kon 
Published: October 2002

AbstractThe phase behavior of a partially miscible blend of poly(ethylene oxide) (PEO) and cellulose acetate butyrate (CAB) and the crystalline microstructure of PEO in the blend were studied with differential scanning calorimetry (DSC), optical microscopy, and synchrotron small‐angle X‐ray scattering (SAXS) methods. PEO/CAB showed a lower critical solution temperature (LCST) of 168 °C at the critical composition of PEO of 60 wt %. All blend compositions showed a single glass‐transition temperature (Tg) when they were prepared at temperatures lower than the LCST. However, with increasing CAB content, Tg of the blend changed abruptly at 70 wt % CAB; that is, a cusp existed. Below 70 wt % CAB, the change in Tg with blend composition was predicted by the Brau–Kovacs equation, whereas this change was predicted by the Fox equation at higher CAB contents. A gradual but small depression of the melting point of PEO in the blend with an increasing amount of CAB suggested that the PEO/CAB blends exhibited a weak intermolecular interaction. From DSC and SAXS experiments, it was found that amorphous CAB was incorporated into the interlamellar region of PEO for blends with less than 20 wt % CAB, whereas it was segregated to exist in the interfibrillar region in PEO for other blends with larger amounts of CAB. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1673–1681, 2002
Melt‐state polymer chain dimensions as a function of temperature
Authors: Krishnamoorti Ramanan , Graessley William W. , Zirkel Achim , Richter Dieter , Hadjichristidis Nikos , Fetters Lewis J. , Lohse David J. 
Published: October 2002

AbstractThe unperturbed chain dimensions (〈R2〉o/M) of cis/trans‐1,4‐polyisoprene, a near‐atactic poly(methyl methacrylate), and atactic polyolefins were measured as a function of temperature in the melt state via small‐angle neutron scattering (SANS). The polyolefinic materials were derived from polydienes or polystyrene via hydrogenation or deuteration and represent structures not encountered commercially. The parent polymers were prepared via lithium‐based anionic polymerizations in cyclohexane with, in some cases, a polymer microstructure modifier present. The polyolefins retained the near‐monodisperse molecular weight distributions exhibited by the precursor materials. The melt SANS‐based chain dimension data allowed the evaluation of the temperature coefficients [dln 〈R2〉o/dT(κ)] for these polymers. The evaluated polymers obeyed the packing length (p)‐based expressions of the plateau modulus, G = kT/np3 (MPa), and the entanglement molecular weight, Me = ρNanp3 (g mol−1), where nt denotes the number (∼21) of entanglement strands in a cube with the dimensions of the reptation tube diameter (dt) and ρ is the chain density. The product np3 is the displaced volume (Ve) of an entanglement that is also expressible as pd or kT/G. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1768–1776, 2002
Improved numerical algorithm for exploring block copolymer mesophases
Authors: Rasmussen K. Ø. , Kalosakas G. 
Published: October 2002

AbstractWe present an improved algorithm of the self‐consistent mean‐field implementation that has been recently proposed for the calculation of block copolymer self‐assembly. Without requiring prior knowledge of the symmetry of the mesophase segregation, the algorithm is numerically stable and significantly faster than previously proposed methods. These advantages provide a valuable tool for combinatorial screening of novel stable and metastable structural phases of block copolymers. We apply the method and demonstrate complex mesophases in linear, asymmetric triblock copolymer melts. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1777–1783, 2002
Ductile–brittle‐transition phenomenon in polypropylene/ethylene‐propylene‐diene rubber blends obtained by dynamic packing injection molding: A new understanding of the rubber‐toughening mechanism
Authors: Wang Yong , Fu Qiang , Li Qijun , Zhang Gong , Shen Kaizhi , Wang Yu‐Zhong 
Published: October 2002

AbstractFor a more complete understanding of the toughening mechanism of polypropylene (PP)/ethylene‐propylene‐diene rubber (EPDM) blends, dynamic packing injection molding was used to control the phase morphology and rubber particle orientation in the matrix. The relative impact strength of the blends increased at low EPDM contents, and then a definite ductile–brittle (D–B) transition was observed when the EPDM content reached 25 wt %, at which point blends should fail in the ductile mode with conventional molding. Wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to investigate the shear‐induced crystal structure, morphology, orientation, and phase separation of the blends. WAXD results showed that the observed D–B transition took place mainly for a constant crystal structure (α form). Also, no remarkable changes in the crystallinity and melting point of PP were observed by DSC. The highly oriented and elongated rubber particles were seen via SEM at high EPDM contents. Our results suggest that Wu's criterion is no longer valid when dispersed rubber particles are elongated and oriented. The possible fracture mechanism is discussed on the basis of the stress concentration in a filler‐dispersed matrix. It can be concluded that not only the interparticle distance but also the stress fields around individual particles play an important role in polymer toughening. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2086–2097, 2002
Ultrafine fibrous cellulose membranes from electrospinning of cellulose acetate
Authors: Liu Haiqing , Hsieh You‐Lo 
Published: October 2002

AbstractThree solvents, that is, acetone, acetic acid, and dimethylacetamide (DMAc), with a range of solubility parameter δ, surface tension γ, viscosity η and boiling temperature were used to generate mixtures for electrospinning cellulose acetate (CA) (degree of substitution, DS = 2.45). Although none of these solvents alone enables continuous formation of fibers, mixing DMAc with either acetone or acetic acid produced suitable solvent systems. The 2:1 acetone:DMAc mixture is the most versatile mixture because it allows CA in the 12.5–20% concentration range to be continuously electrospun into fibrous membranes. These CA solutions have η between 1.2 and 10.2 poise and γ around 26 dyne/cm and produce smooth fibers with diameters from 100 nm to ∼1 μm. Fiber sizes generally decrease with decreasing CA concentrations. The nature of the collectors affects the morphology as well as packing of fibers. Fibers collected on paper have more uniform sizes, smooth surfaces, and fewer defects, whereas fibers collected on water are more varied in size. Electrically conductive solid collectors, such as Al foil and water, favor more tightly packed and less porous membranes. Porous collectors, like paper and copper mesh, produce highly porous membranes. The pores in membranes collected on the Al foil and paper are much better interconnected in the planar directions than those in membranes collected on water. There is evidence that electrospinning induces order in the fibers. Deacetylation of CA membranes is more efficient and complete in NaOH/ethanol than in aqueous NaOH, producing DS values between 0.15 and 2.33 without altering fiber surfaces, packing, or organization. The fully regenerated cellulose membranes are similarly hydrophilic as commodity cellulose fibrous matrices but absorb nearly 10 times as much water. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2119–2129, 2002
Prostate cancer and health‐related quality of life: a review of the literature
Authors: Eton David T. , Lepore Stephen J. 
Published: October 2002

AbstractWith the established effectiveness of diverse treatments for prostate cancer, identification of the physical and psychosocial consequences of the disease and various treatments becomes critical. We review the literature on the effects of prostate cancer and its treatment on health‐related quality of life (HRQoL). Studies show that prostate cancer and its treatment affect both disease‐specific HRQoL (i.e. urinary, sexual, and bowel function) as well as general HRQoL (i.e. energy/vitality, performance in physical and social roles). Yet, these effects appear to differ across stage of disease and type of treatment. We outline evidence from three sources: (1) studies that compare men with the disease with an age‐matched sample of men without the disease, (2) studies that assess men with the disease across time, and (3) cross‐sectional studies that highlight predictors of HRQoL. Future research directions are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Foreign body aspiration: What is the outcome?
Authors: Karakoç Fazilet , Karadağ Bülent , Akbenlioğlu Cengiz , Ersu Refika , Yıldızeli Bedrettin , Yüksel Mustafa , Dağlı Elif 
Published: October 2002

AbstractUndiagnosed and retained foreign bodies may result in serious complications such as pneumonia, atelectasis, or bronchiectasis. We reviewed a total of 174 children with foreign body aspiration (FBA). Clinical, radiological, and bronchoscopic findings of these patients were evaluated according to the nature of foreign body and elapsed time from aspiration to diagnosis.Significant differences were noted between patients with organic and inorganic FBA in terms of clinical and radiological findings. Cough, recurrent pneumonia, and fever were the most common presenting symptoms in patients with delayed diagnosis. Long‐term follow‐up was available for 110 patients for a mean duration of 37.8 ± 23.7 months (range, 1–88 months). We evaluated the course of recovery after bronchoscopic removal. Organic FBA was of comparable duration as for inorganic FBA, and prolonged follow‐up was associated with increased risk of persistent symptoms and bronchiectasis (P < 0.001). The risk of long‐term complications increased with increasing elapsed time from aspiration to diagnosis; complications were as high as 60% in children who were diagnosed 30 days after FBA (P = 0.0035). Bronchiectasis was a major complication, found in 25% of patients whose diagnosis was delayed by more than 30 days (P = 0.0001). Three patients with bronchiectasis underwent lobectomy. Patients with persistent asthma‐like symptoms such as cough and wheezing required treatment with inhaled corticosteroids and bronchodilators. The positive response to this treatment was thought to be a confirmation of the development of transient bronchial hyperresponsiveness induced by foreign bodies.We conclude that timely diagnosis and appropriate treatment of FBA is important to prevent long‐term complications in affected children. Pediatr Pulmonol. 2002; 34:30–36. © 2002 Wiley‐Liss, Inc.
Beclomethasone dipropionate and salbutamol by metered dose inhaler in infants and small children with recurrent wheezing
Authors: Barrueto Luis , Mallol Javier , Figueroa Luis 
Published: October 2002

AbstractThe efficacy of beclomethasone dipropionate (BDP) to control respiratory symptoms was evaluated in 31 children under age 2 years with recurrent wheezing. The study was conducted in a double‐blind, parallel, and placebo‐controlled fashion. The two study groups received either salbutamol plus BDP 200 μg bid by metered dose inhaler (MDI) with a spacer, or salbutamol MDI plus a placebo. Inhaled corticosteroid (IC) and placebo were administered for 8 weeks. Patients were seen every 2 weeks as outpatients, and their progress was evaluated by clinical examination and a daily symptom score card.At the end of the study, patients in both groups had significantly decreased symptoms. No significant difference was found between BDP and placebo groups regarding clinical score, number of salbutamol doses, sleep disturbances, number of symptom‐free days, feelings of insecurity of mothers regarding the infants' life due to wheezing, and mothers' perceptions of progress in their infants' respiratory symptoms.We conclude that salbutamol plus 200 μg bid of BDP inhaled from an MDI with a spacer for 8 weeks is no better than salbutamol alone for decreasing recurrent wheezing in small children under age 24 months. Pediatr Pulmonol. 2002; 34:52–57. © 2002 Wiley‐Liss, Inc.
Are tidal volume measurements in neonatal pressure‐controlled ventilation accurate?
Authors: Chow Lily C. , Vanderhal Andre , Raber Jorge , Sola Augusto 
Published: October 2002

AbstractBedside pulmonary mechanics monitors (PMM) have become useful in ventilatory management in neonates. These monitors are used more frequently due to recent improvements in data‐processing capabilities. PMM devices are often part of the ventilator or are separate units. The accuracy and reliability of these systems have not been carefully evaluated.We compared a single ventilatory parameter, tidal volume (Vt), as measured by several systems. We looked at two freestanding PMMs: the Ventrak Respiratory Monitoring System (Novametrix, Wallingford, CT) and the Bicore CP‐100 Neonatal Pulmonary Monitor (Allied Health Care Products, Riverside, CA), and three ventilators with built‐in PMM: the VIP Bird Ventilator (Bird Products Corp., Palm Springs, CA), Siemens Servo 300A (Siemens‐Elema AB, Solna, Sweden), and Drager Babylog 8000 (Drager, Inc., Chantilly, VA). A calibrated syringe (Hans Rudolph, Inc., Kansas City, MO) was used to deliver tidal volumes of 4, 10, and 20 mL to each ventilator system coupled with a freestanding PMM. After achieving steady state, six consecutive Vt readings were taken simultaneously from the freestanding PMM and each ventilator. In a second portion of the bench study, we used pressure‐control ventilation and measured exhaled tidal volume (Vte) while ventilating a Bear Test Lung with the same three ventilators. We adjusted peak inspiratory pressure (PIP) under controlled conditions to achieve the three different targeted tidal volumes on the paired freestanding PMM. Again, six Vte measurements were recorded for each tidal volume. Means and standard deviations were calculated.The percentage difference in measurement of Vt delivered by calibrated syringe varied greatly, with the greatest discrepancy seen in the smallest tidal volumes, by up to 28%. In pressure control mode, Vte as measured by the Siemens was significantly overestimated by 20–95%, with the biggest discrepancy at the smallest Vte, particularly when paired with the Bicore PMM. Vte, as measured by the VIP Bird and Drager paired with the Ventrak PMM, had a tendency to underestimate Vt by up to 25% at the smallest Vte. However, when paired with the Bicore PMM, these same two ventilators read over target by up to 18%.Under controlled laboratory conditions, we demonstrated that true delivered Vte, as measured by the three ventilators and two freestanding PMM, differed markedly. In general, decreasing dynamic compliance of the tubing was not associated with greater inaccuracy in Vte measurements. Pediatr Pulmonol. 2002; 34:196–202. © 2002 Wiley‐Liss, Inc.
Sleep and breathing in Prader‐Willi syndrome
Authors: Nixon Gillian M. , Brouillette Robert T. 
Published: October 2002

AbstractPrader‐Willi syndrome (PWS) is a genetic disorder, with hypotonia being the predominant feature in infancy, and developmental delay, obesity, and behavioral problems becoming more prominent in childhood and adolescence. Children with this disorder frequently suffer from excessive daytime sleepiness and have a primary abnormality of the circadian rhythm of rapid eye movement sleep. They also have primary abnormal ventilatory responses to hypoxia and hypercapnia, and these abnormalities may be exacerbated by obesity. Children with PWS are at risk of a variety of abnormalities of breathing during sleep, including obstructive sleep apnea and sleep‐related alveolar hypoventilation. Clinical evaluation should include a careful history of sleep‐related symptoms and assessment of the upper airway and lung function. Polysomnography should be considered for those with symptoms suggestive of sleep‐disordered breathing. Treatment options depend on the underlying problem, but may include behavioral interventions, weight control, adenotonsillectomy, and nocturnal ventilation. Pediatr Pulmonol. 2002; 34:209–217. © 2002 Wiley‐Liss, Inc.
Scoring residue conservation
Authors: Valdar William S.J. 
Published: October 2002

AbstractThe importance of a residue for maintaining the structure and function of a protein can usually be inferred from how conserved it appears in a multiple sequence alignment of that protein and its homologues. A reliable metric for quantifying residue conservation is desirable. Over the last two decades many such scores have been proposed, but none has emerged as a generally accepted standard. This work surveys the range of scores that biologists, biochemists, and, more recently, bioinformatics workers have developed, and reviews the intrinsic problems associated with developing and evaluating such a score. A general formula is proposed that may be used to compare the properties of different particular conservation scores or as a measure of conservation in its own right. Proteins 2002;48:227–241. © 2002 Wiley‐Liss, Inc.
Thermal folding and mechanical unfolding pathways of protein secondary structures
Authors: Cieplak Marek , Hoang Trinh Xuan , Robbins Mark O. 
Published: October 2002

AbstractMechanical stretching of secondary structures is studied through molecular dynamics simulations of a Go‐like model. Force versus displacement curves are studied as a function of the stiffness and velocity of the pulling device. The succession of stretching events, as measured by the order in which contacts are ruptured, is compared to the sequencing of events during thermal folding and unfolding. Opposite cross‐correlations are found for an α‐helix and a β‐hairpin structure. In a tandem of two α‐helices, the two constituent helices unravel nearly simultaneously. A simple condition for simultaneous versus sequential unraveling of repeat units is presented. Proteins 2002;49:104–113. © 2002 Wiley‐Liss, Inc.
Conformational states of the glucocorticoid receptor DNA‐binding domain from molecular dynamics simulations
Authors: Bredenberg Johan , Nilsson Lennart 
Published: October 2002

AbstractMolecular dynamics simulations (MD) have been performed on variant crystal and NMR‐derived structures of the glucocorticoid receptor DNA‐binding domain (GR DBD). A loop region five residues long, the so‐called D‐box, exhibits significant flexibility, and transient perturbations of the tetrahedral geometry of two structurally important Cys4 zinc finger are seen, coupled to conformational changes in the D‐box. In some cases, one of the Cys ligands to zinc exchanges with water, although no global distortion of the protein structure is observed. Thus, from MD simulation, dynamics of the D‐box could partly be explained by solvent effects in conjunction with structural reformation of the zinc finger. Proteins 2002;49:24–36. © 2002 Wiley‐Liss, Inc.
Structural effects of dinotefuran and analogues in insecticidal and neural activities
Authors: Kiriyama Kazuhisa , Nishimura Keiichiro 
Published: October 2002

AbstractThe insecticidal potencies of dinotefuran and analogues against the adult male American cockroach, Periplaneta americana (L) were measured by injection with or without metabolic inhibitors. The potency of dinotefuran was close to those of clothianidin and imidacloprid under the conditions used. The nerve‐excitatory and nerve‐blocking activities were measured with central nerve cords of P americana. The nerve‐excitatory activity of dinotefuran was lower than that of imidacloprid, but was comparable with that of clothianidin. The nerve‐blocking activity of dinotefuran was comparable with that of imidacloprid and slightly higher than that of clothianidin. Quantitative analyses showed that variations in the insecticidal activity were better correlated with variations in the nerve‐blocking activity than with those in the nerve‐excitatory activity when the contribution of the hydrophobic factor was allowed for.© 2002 Society of Chemical Industry
Enhanced conditioned inhibitory avoidance by a combined extract of Zingiber officinale and Ginkgo biloba
Authors: Topic B. , Hasenöhrl R. U. , Häcker R. , Huston J. P. 
Published: October 2002

AbstractPrevious work has shown that intragastric administration of Zingicomb®, a preparation consisting of Zingiber officinale and Ginkgo biloba extracts, has anxiolytic‐like properties. The aim of the present study was to assess the effects of acute treatment with this preparation on inhibitory avoidance learning. The influence of pre‐trial administered Zingicomb (ZC) on inhibitory avoidance conditioning was investigated in adult male Wistar rats, with a one‐trial step‐through avoidance task. The animals were treated intragastrically with either vehicle, 0.5, 1, 10 or 100 mg/kg ZC 60 min prior to the acquisition trial. When tested 24 h after training, rats which had received 10 mg/kg ZC exhibited significantly longer step‐through latencies than vehicle treated animals. This result, thus, demonstrates the beneficial effects of Zingicomb on conditioned inhibitory avoidance. Unlike conventional anxiolytic drugs, such as the benzodiazepines, which tend to have amnesic properties, this phytopharmacon is a potent anxiolytic agent which, additionally, can facilitate performance on a learning task, indicating promising clinical applications. Copyright © 2002 John Wiley & Sons, Ltd.
ent‐Kaur‐16‐en‐19‐oic acid, a KB cells cytotoxic diterpenoid from Elaeoselinum foetidum
Authors: Mongelli E. , Pomilio A. B. , Sánchez J. Bustamante , Guerra F. M. , Massanet G. Martínez 
Published: October 2002

AbstractToxic and cytotoxic activities of the toxic plant Elaeoselinum foetidum (Apiaceae) were evaluated using the brine shrimp toxicity (BST) and KB cell cytotoxicity assays. The active chloroform extract was subjected to a bioactivity‐directed fractionation, monitored by the BST assay, that led to the isolation of the diterpenoid ent‐kaur‐16‐en‐19‐oic acid. This compound was potent against the brine shrimp (LC50 = 4.8 μg/mL) and KB cells (IC50 = 1.6 μg/mL). Copyright © 2002 John Wiley & Sons, Ltd.
A sensitivity analysis of an integrated model for joint determination of economic design of $\overline{x}$‐control charts, economic production quantity and production run length for a deteriorating production system
Authors: Lam K. K. , Rahim M. A. 
Published: October 2002

AbstractThis study presents an integrated model for the joint economic design of $\overline{x}$‐control charts and maintenance schedules and, simultaneously, determines the economic production quantity and production run length for a deteriorating production system. The operating state of the production process is classified as either in control or out of control. In the latter state, the process produces some defective items. An $\overline{x}$‐control chart is used to monitor the process mean. Both uniform and non‐uniform inspection schemes are adopted. Inspection and maintenance are performed simultaneously. Replacement cost is assumed to be very high. The process failure mechanism is assumed to follow a general probability distribution with an increasing failure rate. The concept of a truncated production cycle is introduced. The production cycle begins when a new component is installed and ends with a repair after the detection of a failure or after a specified number of inspection intervals, $m$, whichever occurs first. The effects of preventive maintenance on quality control are discussed. Numerical examples are provided to evaluate the performance of the model. Sensitivity analyses are conducted to study the effects of various model parameters. Copyright © 2002 John Wiley & Sons, Ltd.