bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical deformation and electrical breakdown of PEN at high electric fields
Authors: Lotfy Ahmed , Chávez‐Lara José Fidel , Boudou Laurent , Martinez‐Vega Juan 
Published: August 2007

AbstractIn this work, samples of amorphous and semicrystalline PEN (polyethylene‐2,6‐naphthalene dicarboxylate) were subjected to DC electric fields for different durations up to their dielectric breakdown, with or without depolarization. The field‐induced mechanical strains in the samples were studied by means of a nondestructive optical technique without resorting to any physical contact. The results showed that amorphous samples were more vulnerable to the field‐induced mechanical deformation when compared with similar semicrystalline samples. However, both morphologies showed in some samples contradictory behavior at prebreakdown field strength, some caused yielding of the polymer while the others seemed to have the opposite effect. In the latter category, yet some showed the maximum yield point at a particular critical field starting from which the deformation began to diminish significantly to reach a total cancellation at the breakdown field. This critical field quantified at 260 kV/mm is probably a pronouncement of critical ageing and breakdown in PEN. The deformation seems to be an evolution very similar to the evolution of DC current at high fields. Furthermore, the varying response of the samples implies further work to be undertaken to validate a clear mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Homogeneous methylolation of melamine: Mathematical modeling
Authors: Nicolau V. V. , Estenoz D. A. , Meira G. R. 
Published: August 2007

AbstractA novel mathematical model is presented on the methylolation of melamine with formaldehyde at 48°C and pH 9.0. The model assumes an instantaneous hydration/dehydration of formaldehyde and the methylolation mechanism of Gordon et al. (J Appl Polym Sci 1966, 10, 1153). The 24 kinetic constants were adjusted to experimental measurements by Tomita (J Polym Sci 1977, 15, 2347). The model predicts the evolutions of the comonomers and the nine methylolated species. This is the first article of a series that aims at developing a detailed model for the industrial synthesis of melamine–formaldehyde resins. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Mechanical and morphological properties of lyocell blends: Comparison with lyocell nanocomposites (I)
Authors: Chang Jin‐Hae , Nam Si Wook , Jang Seo‐Won 
Published: August 2007

AbstractThe mechanical properties and morphologies of polyblends of lyocell with three different fillers are compared. Poly(vinyl alcohol) (PVA), poly(vinyl alcohol‐co‐ethylene) (EVOH), and poly(acrylic acid‐co‐maleic acid) (PAM) were used as fillers in blends with lyocell produced through solution blending. The variations of their properties with polymer matrix filler content are discussed. The ultimate tensile strength of the PVA/lyocell blend is highest for a blend lyocell content of 30 wt %, and decreases as the lyocell content is increased up to 40 wt %. The ultimate tensile strengths of the EVOH/lyocell and PAM/lyocell blends are highest for a lyocell loading of 20 wt %, and decrease with the increasing filler content. The variations in the initial moduli of the blends with filler content are similar. Of the three blend systems, the blends with PVA exhibit the best tensile properties. Lyocell/organoclay hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium–Mica (C12PPh‐ Mica) as the organoclay. The variation of the mechanical tensile properties of the hybrids with the matrix polymer organoclay content was examined. These properties were found to be optimal for an organoclay content of up to 5 wt %. Even polymers with low organoclay contents exhibited better mechanical properties than pure lyocell. The addition of organoclay to lyocell to produce nanocomposite films was found to be less effective in improving its ultimate tensile strength than blending lyocell with the polymers. However, the initial moduli of the nanocomposites were found to be higher than those of the polyblend films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation of poly(acrylic acid‐co‐acrylamide)/kaolin and release kinetics of urea from it
Authors: Liang Rui , Liu Mingzhu 
Published: August 2007

AbstractA series of poly(acrylic acid‐co‐acrylamide)/kaolin [poly(AA‐co‐Am)/kaolin] composites were prepared by aqueous solution copolymerization of partially neutralized acrylic acid and acrylamide in the presence of kaolin nanopowder, which was synthesized to act as a release carrier of urea fertilizer. The superabsorbent composite was swollen in aqueous solution of urea to load urea, and the effect of urea concentration on the swelling was investigated. Furthermore, the effects of the contents of crosslinker, kaolin, and acrylamide, the neutralization degree of acrylic acid, and temperature, pH, and ionic strength of release medium on water absorbency and diffusion coefficient of urea release from poly(AA‐co‐Am)/kaolin were studied systematically. It was found that urea loading percentage could be adjusted by urea concentration of swelling medium, and urea diffusion coefficient could be regulated through the contents of crosslinker, kaolin, and acrylamide, and the neutralization degree of acrylic acid. Additionally, temperature and ionic strength of release medium may also affect the urea release process. The conclusions obtained could provide theoretical basis for urea diffusion behavior in superabsorbent used in agriculture. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Medium‐term horizon volatility forecasting: A comparative study
Authors: Hawkes Richard , Date Paresh 
Published: August 2007

AbstractIn this paper, volatility is estimated and then forecast using unobserved components‐realized volatility (UC‐RV) models as well as constant volatility and GARCH models. With the objective of forecasting medium‐term horizon volatility, various prediction methods are employed: multi‐period prediction, variable sampling intervals and scaling. The optimality of these methods is compared in terms of their forecasting performance. To this end, several UC‐RV models are presented and then calibrated using the Kalman filter. Validation is based on the standard errors on the parameter estimates and a comparison with other models employed in the literature such as constant volatility and GARCH models. Although we have volatility forecasting for the computation of Value‐at‐Risk in mind the methodology presented has wider applications. This investigation into practical volatility forecasting complements the substantial body of work on realized volatility‐based modelling in business. Copyright © 2007 John Wiley & Sons, Ltd.
Male pregnancy in seahorses and pipefish: beyond the mammalian model
Authors: Stölting Kai N. , Wilson Anthony B. 
Published: August 2007

AbstractPregnancy has been traditionally defined as the period during which developing embryos are incubated in the body after egg–sperm union. Despite strong similarities between viviparity in mammals and other vertebrate groups, researchers have historically been reluctant to use the term pregnancy for non‐mammals in recognition of the highly developed form of viviparity in eutherians. Syngnathid fishes (seahorses and pipefishes) have a unique reproductive system, where the male incubates developing embryos in a specialized brooding structure in which they are aerated, osmoregulated, protected and likely provisioned during their development. Recent insights into physiological, morphological and genetic changes associated with syngnathid reproduction provide compelling evidence that male incubation in these species is a highly specialized form of reproduction akin to other forms of viviparity. Here, we review these recent advances, highlighting similarities and differences between seahorse and mammalian pregnancy. Understanding the changes associated with the parallel evolution of male pregnancy in the two major syngnathid lineages will help to identify key innovations that facilitated the development of this unique form of reproduction and, through comparison with other forms of live bearing, may allow the identification of a common set of characteristics shared by all viviparous organisms. BioEssays 29:884–896, 2007. © 2007 Wiley Periodicals, Inc.
Nutrient deprivation induces autophagy as well as apoptosis in Chinese hamster ovary cell culture
Authors: Hwang Sun Ok , Lee Gyun Min 
Published: August 2007

AbstractDuring Chinese hamster ovary (CHO) cell culture for foreign protein production, cells are subjected to programmed cell death (PCD). A rapid death at the end of batch culture is accelerated by nutrient starvation. In this study, type II PCD, autophagy, as well as type I PCD, apoptosis, was found to take place in two antibody‐producing CHO cell lines, Ab1 and Ab2, toward the end of batch culture when glucose and glutamine were limiting. The evidence of autophagy was observed from the accumulation of a common autophagic marker, a 16 kDa form of LC3‐II during batch culture. Moreover, a significant percentage of the total cells (80% of Ab1 cells and 86% of Ab2 cells) showed autophagic vacuoles containing cytoplasmic material by transmission electron microscopy. An increased level of PARP cleavage and chromosomal DNA fragmentation supported that starvation‐induced apoptosis also occurred simultaneously with autophagy. Biotechnol. Bioeng. 2008;99: 678–685. © 2007 Wiley Periodicals, Inc.
Fluorescence‐based soft‐sensor for monitoring β‐lactoglobulin and α‐lactalbumin solubility during thermal aggregation
Authors: Elshereef Rand , Budman Hector , Moresoli Christine , Legge Raymond L. 
Published: August 2007

AbstractA soft‐sensor for monitoring solubility of native‐like α‐lactalbumin (α‐LA) and β‐lactoglobulin (β‐LG) and their aggregation behavior following heat treatment of mixtures under different treatment conditions was developed using fluorescence spectroscopy data regressed with a multivariate Partial Least Squares (PLS) regression algorithm. PLS regression was used to correlate the concentrations of α‐LA and β‐LG to the fluorescence spectra obtained for their mixtures. Data for the calibration and validation of the soft sensor was derived from fluorescence spectra. The process of thermal induced aggregation of β‐LG and α‐LA protein in mixtures, which involves the disappearance of native‐like proteins, was studied under various treatment conditions including different temperatures, pH, total initial protein concentration and proportions of α‐LA and β‐LG. It was demonstrated that the multivariate regression models used could effectively deconvolute multi‐wavelength fluorescence spectra collected under a variety of process conditions and provide a fairly accurate quantification of respective native‐like proteins despite the significant overlapping between their emission profiles. It was also demonstrated that a PLS model can be used as a black‐box prediction tool for estimating protein aggregation when combined with simple mass balances. Bioeng. 2008;99: 567–577. © 2007 Wiley Periodicals, Inc.
A One‐Pot Synthesis of (E)‐Disubstituted Alkenes by a Bimetallic [Rh–Pd]‐Catalyzed Hydrosilylation/Hiyama Cross‐Coupling Sequence
Authors: Thiot Carine , Schmutz Marc , Wagner Alain , Mioskowski Charles 
Published: August 2007

AbstractA bimetallic [Rh–Pd] catalyst was prepared by soaking into an iodide ionic gel an equimolar solution of [RhCl(PPh3)3] and Pd(OAc)2 in CH2Cl2. Its catalytic activity was evaluated by rhodium‐catalyzed hydrosilylation (H), palladium‐catalyzed Hiyama coupling (C), and in the one‐pot hydrosilylation/Hiyama coupling sequence (H/C). It was found that the homogeneous combination [RhCl(PPh3)3]/NaI was a superior system compared to the polyionic mono‐ and bimetallic rhodium catalysts in the hydrosilylation of terminal alkynes. Interestingly, the most effective catalyst in terms of stereo‐ and chemoselectivities was observed to be the bimetallic ionic gel [Rh–Pd] in the one‐pot process leading to (E)‐alkenes with good yields. The remarkable stereocontrol is ascribed to a beneficial Pd‐catalyzed isomerization from the mixture of stereoisomeric vinylsilanes obtained in the initial hydrosilylation step into the more stable (E)‐adduct. The [Rh–Pd] heterogeneous catalyst also showed a higher chemoselectivity than the homogeneous catalytic combination, and no detrimental formation of Sonogashira side product was observed due to an ionic‐gel‐mediated kinetic modulation. To illustrate its scope and limitations, the described one‐pot bimetallic catalytic sequence was extended to functionalized terminal alkynes and various iodide substrates. Conjugated systems, such as hydroxycinnamaldehyde, dienes, and trienes, were synthesized in good overall yields. To avoid deactivation of the Rh species, N‐heterocyclic iodides had to be added sequentially after completion of hydrosilylation.
Thoughts About the Abnormalities in the Electrocardiogram of Patients with Acute Myocardial Infarction with Emphasis on a more Accurate Method of Interpreting ST‐segment Displacement: Part I
Authors: Willis Hurst J. 
Published: August 2007

AbstractThe QRS, S‐T, and T wave abnormalities produced by the usual myocardial infarction are discussed in Part I of this manuscript.The recent guidelines supplied by the ACC/AHA Practice Guidelines divide primary S‐T segment displacement into S‐T segment elevated myocardial infarction (STEMI) and non S‐T segment elevated myocardial infarction (NSTEMI). Accordingly, the electrophysiologic mechanisms responsible for epicardial and subendocardial injury that produce the S‐T segment abnormalities are discussed in this manuscript. In this regard, the author suggests that the Grant method of interpreting the 12 lead electrocardiogram, which uses basic principles and vector concepts, is a more accurate method of identifying epicardial injury and subendocardial injury than memorizing the rules provided by the guidelines. An electrocardiogram is shown to illustrate this point. In Addition, the author expresses his personal view that labeling an electrocardiogram as NSTEMI but not stating what is actually present in the tracing is a cumbersome method of communication. The author believes it is better communication to state what is present rather than to state what is not present. At best, the result of both assessments should be stated in the interpretation.Part II of the manuscript is devoted to a discussion as to why treatment with thrombolytic or percutaneous coronary intervention is more effective in patients whose electrocardiograms reveal epicardial injury than it is in patients whose electrocardiograms reveal subendocardial injury or no injury. Copyright © 2007 Wiley Periodicals, Inc.
The influence of socio‐demographic and illness variables on quality of life in acute psychiatric inpatients
Authors: Hodgson Z. G. , Pattison C. , Bostock L. , Murphy T. , Stewart M. E. 
Published: August 2007

AbstractThe mental‐health literature highlights the importance of improved quality of life as an explicit goal of the mental‐health service. Recent work indicates that assessment of subjective quality of life can be feasible and meaningful in individuals with psychiatric disorders. Although a number of studies have examined the influence of demographic variables on subjective quality of life in individuals with psychiatric disorders, there remains a paucity of studies that have made comparisons between diagnoses in inpatient populations. We used the WHOQOL‐BREF to examine the influence of different psychiatric diagnoses on quality of life and investigated whether the relationship between demographic variables and quality of life was the same across diagnoses. We found that the relationship between demographic and illness variables was complex, with inconsistent effects across WHOQOL‐BREF domains. Certain domains of the WHOQOL‐BREF were more sensitive to the influence of psychiatric diagnosis than others. Copyright © 2007 John Wiley & Sons, Ltd.
Anemia and Interleukin‐6 Are Associated with Faster Progression to End‐Stage Renal Disease
Authors: Neves Pedro L. , Morgado Elsa , Baptista Alexandre , Sampaio Sandra , Faísca Marília , Silva Ana P. , Santos João P. 
Published: August 2007

AbstractBACKGROUNDVarious classical risk factors are associated with the progression of chronic kidney disease (CKD) and, recently, novel risk factors have been identified. The aim of this study was to identify factors associated with the risk of end‐stage renal disease (ESRD) in a population of patients with CKD stages 4 and 5.METHODSWe prospectively followed renal patients at our clinic (mean glomerular filtration rate [GFR] of 16.9 mL/min) for an average of 12.4 months. The end point was initiation of dialysis. For comparisons between groups, we used Student's t‐ and χ2 tests. Using the Cox proportional hazard model, we regressed several independent variables on time to dialysis. We also evaluated the influence of IL‐6 on the progression of CKD, using the Kaplan–Meier method.RESULTSNinety‐five patients (54 men; mean age, 69.4 years) participated in the study. A greater proportion of those who began dialysis were male (p = 0.003). Their GFR (p = 0.0001), hemoglobin (p = 0.024), and the albumin (p = 0.034) levels were lower and their IL‐6 was higher (p = 0.002) than those who did not begin dialysis. We also found that male sex (p = 0.001), hypertension (p = 0.043), lower GFR level (p = 0.018), lower hemoglobin level (p = 0.039), and higher IL‐6 level (p = 0.0001) predicted faster progression to ESRD. Patients whose IL‐6 levels were in the upper quartiles had lower kidney survival after 12 months (log rank = 35.1, p = 0.0001).CONCLUSIONIn our population, anemia and interleukin‐6 were associated with faster progression to ESRD.
Rapid acquisition of operant conditioning in 5‐day‐old rat pups: A new technique articulating suckling‐related motor activity and milk reinforcement
Authors: Arias Carlos , Spear Norman E. , Molina Juan Carlos , Molina Agustin , Molina Juan Carlos 
Published: August 2007

AbstractNewborn rats are capable of obtaining milk by attaching to a surrogate nipple. During this procedure pups show a gradual increase in head and forelimb movements oriented towards the artificial device that are similar to those observed during nipple attachment. In the present study the probability of execution of these behaviors was analyzed as a function of their contingency with intraoral milk infusion using brief training procedures (15 min). Five‐day‐old pups were positioned in a smooth surface having access to a touch‐sensitive sensor. Physical contact with the sensor activated an infusion pump which served to deliver intraoral milk reinforcement (Paired group). Yoked controls received the reinforcer when Paired neonates touched the sensor. Paired pups trained under a continuous reinforcement schedule emitted significantly more responses than Yoked controls following two (Experiment 1) or one training session (Experiment 2). These differences were also observed during an extinction session conducted immediately after training. The level of maternal deprivation before training (3 or 6 hr) or the volume of milk delivered (1.0 or 1.5 µl per pulse) did not affect acquisition or extinction performances. In addition, it was observed that the rate of responding of Paired pups during the early phase of the extinction session significantly predicted subsequent levels of acceptance of the reinforcer. These results indicate that the frequency of suckling‐related behaviors can be rapidly modified by means of associative operant processes. The operant procedure here described represents an alternative tool for the ontogenetic analysis of self‐administration or behavior processes of seeking. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 576‐588, 2007.
Decline in age‐dependent, MK801‐induced injury coincides with developmental switch in parvalbumin expression: Cingulate and retrosplenial cortex
Authors: Lema Tomé Carla M. , Miller Ryan , Bauer Clayton , Nottingham Charles , Smith Chelsey , Blackstone Kaitlin , Brown Lauren , Bryan Rachael , Leigh Adam , Brady Megan , Busch Jamie , Turner Christopher P. 
Published: August 2007

AbstractAge‐dependent, MK801‐induced, activated caspase‐3 expression in the postnatal brain is generally not observed in neurons expressing calcium‐binding proteins (CaBPs), suggesting that apoptosis and calcium buffering are inversely related. In regions such as the cingulate and retrosplenial cortex, injury peaks at postnatal Day 7 (P7) and rapidly diminishes thereafter, whereas expression of calbindin (CB) and calretinin (CR) was relatively low from P0 to P7 and steadily increased from P7 to P14. At ages thereafter, CB and CR expression either remained stable then declined or rapidly declined. Parvalbumin (PV) was generally low‐absent prior to P7 but expression dramatically increased from P10 onwards, peaking at P21. These studies suggest calcium entry (through N‐methyl‐D‐aspartate receptor (NMDARs)) and buffering (by CaBPs) are integral to normal CNS maturation. Because schizophrenia is associated with glutamate hypo‐function, developmental injury, and aberrant CaBP expression, our data indicate that this postnatal brain injury model may offer important insights into the nature of this disorder. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 606‐618, 2007.
The influence of parent–infant cosleeping, nursing, and childcare on cortisol and SIgA immunity in a sample of british children
Authors: Waynforth David 
Published: August 2007

AbstractSubstantial variation in childcare arrangements exists both within and between populations. Research has suggested negative stress‐related outcomes for children who regularly attend daycare facilities. In the present study, 122 cortisol and 94 secretory immunoglobulin A (SIgA) samples from 32 British children aged between 3 and 8 were analyzed using multilevel modeling to assess effects of daycare attendance and other childcare‐related variables on children's stress and SIgA immune function. Parents' reports of children's aggression and family discord within 2 hr of saliva collection were associated with elevated cortisol levels in children. With these acute stressors statistically controlled, retrospective data on parent–child cosleeping showed that children who had coslept in their parent(s) room had lower cortisol levels, as did children who had attended less daycare in the first 4 years of life. The parenting‐related variables did not predict SIgA immunity. The results are discussed in the context of theories of parenting strategies. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 640‐648, 2007.
Dystroglycan protein distribution coincides with basement membranes and muscle differentiation during mouse embryogenesis
Authors: Anderson Claire , Winder Steven J. , Borycki Anne‐Gaëlle 
Published: August 2007

AbstractUsing immunohistochemistry, we have examined β‐Dystroglycan protein distribution in the mouse embryo at embryonic stages E9.5 to E11.5. Our data show that Dystroglycan expression correlates with basement membranes in many tissues, such as the notochord, neural tube, promesonephros, and myotome. In the myotome, we describe the timing of Dystroglycan protein re‐distribution at the surface of myogenic precursor cells as basement membrane assembles into a continuous sheet. We also report on non‐basement‐membrane‐associated Dystroglycan expression in the floor plate and the myocardium. This distribution often corresponds to sites of expression previously reported in adults, suggesting that Dystroglycan is continuously produced during development. Developmental Dynamics 236:2627–2635, 2007. © 2007 Wiley‐Liss, Inc.