bluuebunny/crossref_metadata_2025_split huggingface dataset:
Processing, rheology, and storage stability of recycled EVA/LDPE modified bitumen
Authors: García‐Morales M. , Partal P. , Navarro F.J. , Martínez‐Boza F.J. , Gallegos C. 
Published: January 2007

AbstractThe optimum processing conditions for the manufacture of polymer‐modified bitumens (PMBs), as well as the rheological properties of the final polymer‐bitumen blends, strongly depend on the characteristics of the mixing device used. The present work is focused on the comparison among the kinetics of the mixing process and the rheological properties and microstructural characteristics of PMBs manufactured in two different mixers. Thus, blends of 60/70 penetration grade bitumen and recycled EVA/LDPE were processed in both high and low‐shear devices. Knowledge on the evolution of shear viscosity and microstructure with time, as well as on the mechanical properties of the final polymer‐bitumen blends, was gained from rheological and modulated DSC tests, and optical microscopy. The results obtained demonstrate that processing in the high‐shear device yields a significant decrease in the time needed for the polymer‐bitumen blend to reach the final stage of the manufacturing process, as well as an important reduction in bitumen oxidation and enhanced properties in a wide range of in‐service temperatures. However, polymer‐bitumen blends manufactured in the high‐shear device are not stable during its storage at high temperature. POLYM. ENG. SCI., 47:181–191, 2007. © 2007 Society of Plastics Engineers
Synthesis and characterization of a thermotropic liquid‐crystalline poly[2,5‐bis(4′‐alkoxycarbonylphenyl) styrene]
Authors: Zhu Zhiguo , Zhi Junge , Liu Anhua , Cui Jiaxi , Tang Hui , Qiao Wenqiang , Wan Xinhua , Zhou Qifeng 
Published: January 2007

AbstractWe report the synthesis and characterization of a series of novel mesogen‐jacketed liquid‐crystalline polymers, poly[2,5‐bis(4′‐alkoxycarbonylphenyl)styrene]s (1‐m, where m is the number of carbon atoms in the alkyl tails), along with the corresponding monomers, 2,5‐bis(4′‐alkoxycarbonylphenyl)styrenes (2‐m), and their precursors, 2,5‐bis(4′‐alkoxycarbonylphenyl)toluenes (3‐m). The influence of the tail length on the thermotropic properties of the two types of low‐molecular‐mass compounds and macromolecules was investigated with a combination of differential scanning calorimetry, polarized optical microscopy, and wide‐angle X‐ray diffraction techniques. Except for compound 3‐3, which exhibited a monotropic nematic phase, all members of the low‐molar‐mass molecules developed no mesophase during both heating and cooling processes. The glass‐transition temperatures of the polymers decreased as the tail lengths increased. The 5% weight loss temperatures of all the polymers under a nitrogen atmosphere were above 360 °C, indicating quite high thermal stability. Although polymers 1‐1 and 1‐2 were non‐liquid‐crystalline, columnar nematic phases were observed for the remaining homopolymers with longer alkyl tails. The mesophases of 1‐3 to 1‐9 that developed at high temperatures remained upon cooling to room temperature, whereas those of 1‐10 to 1‐12 disappeared during the cooling process. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 830–847, 2007.
Poly(thienyl‐phenylene)s with macromolecular side chains by oxidative polymerization of well‐defined macromonomers
Authors: Cianga I. , Mercore V. M. , Grigoras M. , Yagci Y. 
Published: January 2007

AbstractWell‐defined polystyrene (PSt), poly(ε‐caprolactone) (PCL) or poly(2‐methyloxazoline) (POx) based polymers containing mid‐ or end‐chain 2,5‐ or 3,5‐dibromobenzene moieties were prepared by controlled polymerization methods, such as atom transfer radical polymerization (ATRP), ring opening polymerization (ROP), or cationic ring opening polymerization (CROP). These polymers were subsequently modified by Suzuki type coupling reactions with 2‐thiophene boronic acid. The resulting polymers, containing a conjugated sequence with 2‐thienyl groups at the extremities, could be further used as macromonomers in chemical oxidative polymerization in the presence of anhydrous FeCl3. Poly(thienyl‐phenylene)s having the respective PSt or PCL chains as lateral subtituents were obtained in this way. All the starting, intermediate, or final polymers were structurally analyzed by spectroscopic methods (1H and 13C NMR, IR) and gel permeation chromatography (GPC) measurements. Thermal behavior of the macromonomers and final polymers was investigated by differential scanning calorimetry (DSC) analyses. Optical properties of the polymers were monitored by UV and fluorescence spectroscopy. The emission spectra of the polymers show a clear bathochromic shift of the λmax emission in all the cases with respect to the monomers because of the extending of the conjugation length. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 848–865, 2007.
Incorporation of silver/carbon nanoparticles into poly(methyl methacrylate) via in situ miniemulsion polymerization and its influence on the glass‐transition temperature
Authors: López‐Martínez Erika I. , Márquez‐Lucero Alfredo , Hernández‐Escobar Claudia A. , Flores‐Gallardo Sergio G. , Ibarra‐Gómez Rigoberto , Yacamán Miguel J. , Zaragoza‐Contreras E. Armando 
Published: January 2007

AbstractSilver/carbon nanoparticles (9 nm) were incorporated, as reinforcements, into a matrix of poly(methyl methacrylate) via in situ miniemulsion polymerization. It was found by differential scanning calorimetry that the glass‐transition temperature of the poly(methyl methacrylate) showed an improvement of 14 °C with only 0.5 wt % nanoparticles in comparison with a pure poly(methyl methacrylate) control, which was also obtained by miniemulsion polymerization under the same conditions. This increase was related to a polymer chain mobility restriction due to a combination of bound plastic and joint plastic shell effects at the interphase and the surrounding regions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 511–518, 2007.
DC characterization of laser‐debonded GaN HEMTs
Authors: Chan C. P. , Leung K. K. , Pilkuhn M. , Surya C. , Yue T. M. , Pang G. , Schweizer H. 
Published: January 2007

AbstractWe report experimental investigation of laser‐assisted debonding of GaN high electron mobility transistors (HEMTs) grown by metalorganic chemical vapor deposition (MOCVD) technique on sapphire substrates. The debonded HEMTs were transferred onto silicon substrate for better thermal dissipation during operation. Dc characterization indicated no degradation in the I–V characteristics as long as the optimized laser power was used in the debonding process. Transmission electron microscopy (TEM) of the AlGaN/GaN heterojunctions before and after the laser debonding process did not indicate any increase in the dislocation density at the heterointerface. We have also conducted detailed characterizations of the low‐frequency noise properties to investigate the defect properties over the entire active area of the device. Experimental data on the voltage noise power spectra measured from the same device before and after laser debonding indicated no significant change in the magnitude of the flicker noise over a wide temperature range. The results of XRD measurements revealed that the FWHM values before and after debonding are basically the same and also suggested that both out‐of‐plane tensile and in‐plane compressive stresses present were both removed after the laser processing. Our results clearly demonstrate that the laser‐assisted debonding process did not result in the increase in the material defect density. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural properties of silica gels prepared from oxalic‐acid‐catalyzed tetraethoxysilane sonohydrolysis
Authors: Donatti D. A. , Ruiz A. Ibañez , Vicelli M. R. , Vollet D. R. 
Published: January 2007

AbstractAbout ∼2.1 × 10−3 mol SiO2 cm−3 and ∼88%‐volume liquid‐phase silica wet gels were prepared from oxalic‐acid‐catalyzed tetraethoxysilane (TEOS) sonohydrolysis. Aerogels were obtained by supercritical CO2 extraction. The samples were analyzed by thermogravimetry, small‐angle X‐ray scattering and nitrogen adsorption. Wet gels can be described as mass fractal structures with fractal dimension D ∼ 1.94 and structural characteristic length ξ changing between ∼3.3 to ∼3.0 nm in the studied range of the catalyst concentration. A fraction of the porosity is apparently eliminated in the supercritical process. The values of the BET specific surface SBET, the total pore volume VP and the mean pore size lP of the aerogels were found to change almost randomly around the mean values SBET = 874 m2 g−1, VP = 0.961 cm3 g−1 and lP = 4.4 nm with catalyst concentration variation. These values were not substantially different from those from an equivalent HCl‐catalyzed aerogel. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of substrates on the statical and dynamical properties of ferroelectric thin films
Authors: Wesselinowa J. M. , Dimitrov Al. B. 
Published: January 2007

AbstractBased on the transverse Ising model using a Green's function technique it is shown that the influence of the substrate induces strong changing of various statical and dynamical properties due to different exchange interactions between the ferroelectric thin film and the substrate. Properties such as the phase transition temperature, the polarization, the soft‐mode energy, the damping and the dielectric function were found to be highly dependent upon the magnitude and the kind (tensile or compressive) of the stress due to the substrate. There is some competition between the surface and substrate effects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of exacerbation rates in asthma and chronic obstructive pulmonary disease: example from the TRISTAN study
Authors: Keene Oliver N. , Jones Mark R. K. , Lane Peter W. , Anderson Julie 
Published: January 2007

AbstractRecurrent events in clinical trials have typically been analysed using either a multiple time‐to‐event method or a direct approach based on the distribution of the number of events. An area of application for these methods is exacerbation data from respiratory clinical trials. The different approaches to the analysis and the issues involved are illustrated for a large trial (n = 1465) in chronic obstructive pulmonary disease (COPD). For exacerbation rates, clinical interest centres on a direct comparison of rates for each treatment which favours the distribution‐based analysis, rather than a time‐to‐event approach. Poisson regression has often been employed and has recently been recommended as the appropriate method of analysis for COPD exacerbations but the key assumptions often appear unreasonable for this analysis. By contrast use of a negative binomial model which corresponds to assuming a separate Poisson parameter for each subject offers a more appealing approach. Non‐parametric methods avoid some of the assumptions required by these models, but do not provide appropriate estimates of treatment effects because of the discrete and bounded nature of the data. Copyright © 2007 John Wiley & Sons, Ltd.
Social disability in different mental disorders
Authors: Rymaszewska J. , Jarosz-Nowak J. , Kiejna A. , Kallert T. , Schützwohl M. , Priebe S. , Wright D. , Nawka P. , Raboch J. 
Published: January 2007

AbstractObjectiveTo assess the social disability of people with different psychiatric disorders.MethodsCross-site survey in five psychiatric hospitals (Dresden, Wrocław, London, Michalovce and Prague). Working-aged patients diagnosed (ICD-10) with schizophrenia and related disorders (F2), affective disorders (F3), anxiety disorders (F4), eating disorders (F5) and personality disorders (F6), were assessed at admission (n = 969) and 3 months after discharge (n = 753) using the Brief Psychiatric Rating Scale and the Groningen Social Disability Schedule. The main outcome measure was Interviewer-rated social disability.ResultsDuring acute episodes patients with personality, eating and schizophrenic disorders functioned less effectively than those with affective or anxiety disorders. After controlling for age and severity of psychopathology, there was no significant effect of the diagnosis (during remission), sex, education and history of disorder on disability. Site, employment and partnership were significant factors for the level of social disability in both measure points.ConclusionSeverity of psychopathological symptoms, not the diagnosis of a mental disorder, was the most significant factor in determining the level of social functioning, particularly during the remission period. Site, employment and partnership appeared as significant factors influencing the level of social disability.
A simple method to rule out dementia with temporal orientation
Authors: Tractenberg Rochelle E. , Weiner Myron F. , Aisen Paul S. , Kaye Jeffrey A. , Fuh Jong-Ling 
Published: January 2007

ObjectiveTo explore the performance of a test of temporal orientation (TTO) comprising four items derived from the Mini‐Mental State Examination over 4 years.MethodsResponses were obtained from two large cohorts participating in longitudinal studies of aging in the United States (352 normal elderly, 98 persons with very mild probable or possible Alzheimer's disease). Sensitivity, specificity, and predictive value (positive, PV+, negative, PV−) of the TTO were estimated for each of four annual visits.ResultsWhen four correct answers were treated as “oriented to time” and 0 to 3 correct answers were treated as “not oriented to time,” sensitivity (to the presence of AD) ranged from 46.0% to 69.2% and PV+ ranged from 32.1% to 49.5%. Specificity (for normal cognition) decreased from 93.2% at the first visit to 81.3% at the fourth visit; TTO performed most reliably in terms of PV−, the probability of normal cognitive function given orientation to time (TTO = 4), which ranged from 92.8% to 95.4%.ConclusionGiven the stability and strength of the predictive negative value of a dichotomized TTO over time, a TTO could contribute to monitoring normal cognitive functioning in longitudinal studies in which cognitive status is not the primary focus. Prospective validation of the TTO is warranted.
A Summary of the Properties of Zabs > Zem Systems and Some Comments on the Origins of QSO Absorption Line Systems
Authors: R J Weymann  , R E Williams  
Published: January 2007

Z
abs > Z
em systems are "real" in the sense of not being artifacts of measuring errors, but Z
em may not represent the true Z of the QSO. However, a specific simple model involving occultation of outflowing gas by an opaque central object produces too much asymmetry in the emission lines. If Z
abs > Z
QSO systems truly exist the least objectionable model involves clouds of gas bound in an associated large cluster.
Lack of detectable C II fine structure in 3 objects (1225+31, 1331+17, 1756+23) suggests the absorbing material is ≳ 500 kpc from the QSO on the basis of ionization arguments, leading to unacceptably large kinetic energies if the absorption is "intrinsic". Defects in the ionization argument are considered.
Preliminary statistical results on low Z
ab Mg II systems require that the effective radius for producing such systems by intervening galaxies must be ∼ 5 times the Holmberg radius, but attempts to detect such galaxies have not been successful.
Finally, it is speculated that a correlation may exist between the column density of the strongest absorption system and multiplicity of absorption systems in a given object suggesting that systems like those in 1756+23 are intrinsic, despite the C II fine-structure argument.
On the Radiative Acceleration of Quasar Absorption Line Clouds
Authors: Peter Goldreich  
Published: January 2007

Radiation may expel dense gas clouds from quasar emission line regions. Small clouds can be accelerated to velocities approaching c if they are confined so as to maintain high densities.
The kinetic energies, inferred from the spectra, of low to medium excitation quasar absorption clouds are too large for radiation pressure to have played a dominant role in their acceleration. If these clouds are physically associated with the quasars, they are probably accelerated by the same stresses that are responsible for their confinement.
Models for absorption clouds based on radiatively driven instabilities in expanding quasar envelopes predict column densities that are much larger than those deduced from observation.
Follicular cysts in dairy cows
Authors: ISOBE Naoki 
Published: January 2007

ABSTRACTFollicular cysts are the most critical reproductive disorder in dairy cows and disturb the normal ovarian cycle, resulting in a prolonged interval from calving to conception. Therefore, this condition causes significant economic losses to the dairy industry. Two direct causal factors for cysts are suggested in this review; ovulation disorder and the delay of regression. Ovulation disorder has been accepted to be a main etiology of cystic follicle. This seems to be caused by the deficiency of positive feedback of estrogen to the hypothalamus, leading to the lack of luteinizing hormone surge. On the other hand, if a large anovulatory follicle is regressed immediately after the failure of ovulation, its follicle does not continue to grow, resulting in no cystic follicle being formed. Therefore, it is proposed that another cause of a cystic follicle is the delay (or absence) of the degeneration system of the follicle. This review will introduce these two causes separately, referring to recent advances in understanding the follicular cyst in dairy cows.
Seasonal changes in digestibility, passage rate and rumen fermentation of alfalfa hay in sika deer (Cervus nippon) under restricted feeding
Authors: ASANO Sanae , IKEDA Shoshichi , KUROKAWA Yuzo , KANDA Shuhei , ITABASHI Hisao 
Published: January 2007

ABSTRACTTo investigate seasonal variations in the digestive functions of sika deer, five female sika deer were provided with an amount of alfalfa hay cubes equivalent to voluntary food intake during winter. We measured the rate at which the food passed through the digestive tract, digestibility and rumen fermentation during the summer (August), autumn (November), winter (February) and spring (May). Total mean retention time in the digestive tract during summer and autumn was numerically longer than that in winter and spring, but the difference did not reach significance. Organic matter and fiber were less digestible in summer and autumn than in winter and spring (P < 0.05), whereas the digestibility of the dry matter tended to vary with the seasons (P < 0.1). Ruminal pH values seasonally changed (P < 0.01), and were the lowest in autumn. The concentration of ruminal ammonia‐nitrogen differed significantly among the seasons (P < 0.05), increasing in winter and decreasing during spring and summer. The numbers of protozoa changed significantly among the seasons (P < 0.05), being higher in autumn than in winter and spring, and intermediate in summer. The concentration of total volatile fatty acids was not seasonally affected, but the molar percentages of propionic acid and butyric acid significantly changed according to season (P < 0.05 and P < 0.01, respectively), and the ratio of acetic to propionic acid tended to change with the seasons (P < 0.1). The results of this study suggested that the digestive functions in sika deer, fed a commercial diet at a restricted level, differed notably among the seasons and these variations might partially be due to environmental effects.
Estimation of dietary lysine requirement using plasma amino acid concentrations in mature thoroughbreds
Authors: OHTA Yoshiyuki , YOSHIDA Tatsuyuki , ISHIBASHI Teru 
Published: January 2007

ABSTRACTFour experiments were conducted to estimate dietary lysine (Lys) requirements using plasma amino acid concentrations as a criterion in mature thoroughbreds. In each experiment four adult thoroughbreds were used. The changes in plasma Lys concentration after feeding were observed in Experiment 1. Blood samples were taken from the cervix vein 0.5 h before, and 1, 3, 5.5, and 10 h after feeding. The plasma Lys concentration increased and remained constant until 3 h after feeding, decreased until 5.5 h and remained constant after then. Therefore, the bleed was done at 3 h after feeding in all later experiments. To make sure of the response speed of the plasma Lys to changes of dietary Lys levels, dietary Lys levels were changed from high to low, and low to high levels in Experiment 2. Blood samples were taken just on the changing day and 1, 2 and 3 days after changing diets. The plasma Lys concentration decreased until 2 days after changing the diet, and then remained constant with advancing days after changing the diet from high Lys to low Lys. On the other hand, the plasma Lys increased until one day after changing the diet, and then remained constant with advancing days after changing dietary Lys levels. Thus, blood samples were taken 3 days after feeding in the next experiments. The possibility of estimating the Lys requirement for maintenance using plasma Lys concentration was elucidated by two methods in Experiments 3 and 4. In Experiment 3, the horses were fed a diet containing 0.33 percent Lys for 3 days. After this the diet was changed to diets containing higher levels of Lys to 0.40, 0.47, 0.54, and 0.61 percent every third day. The Lys requirement was estimated to be 0.46 percent of diet from the response of plasma Lys concentration of five Lys levels. In Experiment 4, a 4 × 4 Latin square design was used for four dietary Lys levels. The Lys requirement was estimated to be 0.47 percent of the diet with a plasma Lys concentration of four Lys levels.
Digestive enzyme activities of pancreas and intestinal digesta in streptozotocin‐induced diabetic piglets
Authors: MURAKAMI Hitoshi , MATSUMOTO Mitsuhito , INOUE Hiroaki , KAJI Yuji 
Published: January 2007

ABSTRACTSix (Landrace × Large White) × Duroc crossbred, castrated weanling piglets were used to evaluate the effect of a streptozotocin (STZ) injection to induce diabetes on the activities of digestive enzymes derived from the pancreas (lipase, amylase, trypsin and chymotrypsin) in the pancreas and intestinal digesta. Fasting plasma glucose after the administration of STZ was maintained at the level of 302–491 mg/dL during this experiment, compared with the level of 89–125 mg/dL in the control group, and they were defined as the STZ‐induced diabetic piglets for about 7 weeks. Although their bodyweight increased in proportion to a quadratic curve (P < 0.0001) during 49 days after the administration of STZ, the growth of the STZ‐induced diabetic piglets was slower compared with the control. The STZ‐injection did not affect the percentage of the pancreas in bodyweight. The administration of STZ in the piglets tended to accelerate the activity of lipase (P = 0.06) and depress the activity of amylase (P = 0.15) or chymotrypsin (P = 0.18), as units/kg bodyweight, in the pancreas. In the case of measurement as units/kg bodyweight, the activities of intestinal digesta in the STZ group showed a tendency to be higher than those in control group, irrespective of the sort of enzymes. In conclusion, STZ‐induced diabetic piglets have a moderate digestive ability and the administration of exogenous digestive enzymes is not necessary when they are used as a diabetic animal model.