bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous measurement of metabolic and acoustic power and the efficiency of sound production in two mole cricket species (Orthoptera:Gryllotalpidae)
Authors: Prestwich Kenneth N. , O'Sullivan Kristin
Published: March 2005

We here report the first simultaneous measurement of metabolic cost of calling, acoustic power and efficiency of sound production in animals –the mole crickets Scapteriscus borellii and S. vicinus(Gryllotalpidae). We measured O2 consumption, CO2production and acoustic power as the crickets called from their burrows in an open room. We utilized their calling burrow as the functional equivalent of a mask. Both species had a respiratory quotient near 0.85, indicative of metabolism based on a mix of carbohydrates and fats. The metabolic rate was significantly higher in S. borellii (11.6 mW g–1)than in S. vicinus (9.0 mW g–1) and averaged about eight- to fivefold greater, respectively, than resting metabolism. In some individuals, metabolic rate decreased by 20% during calling bouts. Costs of refurbishing calling burrows in S. borellii were less than calling costs, due to the behavior's short duration (ca. 15 min) and its relatively low average metabolic rate (4 mW).

Acoustic power was on average sevenfold greater in S. borellii(21.2 vs 2.9 μW) and was more variable within individuals and across species than the metabolic rate. The efficiency of sound production was significantly higher in S. borellii (0.23 vs 0.03%). These values are below published estimates for other insects even though these mole crickets construct acoustic burrows that have the potential to increase efficiency. The cricket/burrow system in both species have an apparent Qln decrement of about 6, indicative of significant internal damping caused by the airspaces in the sand that forms the burrow's walls. Damping is therefore an important cause of the low sound production efficiency. In field conditions where burrow walls are saturated with water and there is less internal damping, calls are louder and sound production efficiency is likely higher.

File tooth depths and file tooth-to-tooth distances correlated with interspecific differences in metabolism and acoustic power much better than with wing stroke rates and plectrum-to-file tooth strike rates. To further investigate these correlations, we constructed two models of energy input to the tegminal oscillator. A model based on transfer of kinetic energy based on differences in tegminal velocity and file tooth spacing showed the most promise. Related calculations suggest that if there are no elastic savings,the power costs to accelerate and decelerate the tegmina are greater than the predicted power input to the tegminal oscillator, and that they are similar in the two species even though S. vicinus has a nearly threefold higher wing stroke rate.
Giant Galápagos tortoises walk without inverted pendulum mechanical-energy exchange
Authors: Zani Peter A. , Gottschall Jinger S. , Kram Rodger
Published: March 2005

Animals must perform mechanical work during walking, but most conserve substantial mechanical energy via an inverted-pendulum-like mechanism of energy recovery in which fluctuations of kinetic energy (KE) and gravitational potential energy (GPE) are of similar magnitude and 180° out of phase. The greatest energy recovery typically occurs at intermediate speeds. Tortoises are known for their slow speeds, which we anticipated would lead to small fluctuations in KE. To have an effective exchange of mechanical energy using the inverted-pendulum mechanism, tortoises would need to walk with only small changes in GPE corresponding to vertical center-of-mass (COM)fluctuations of <0.5 mm. Thus, we hypothesized that giant Galápagos tortoises would not conserve substantial mechanical energy using the inverted-pendulum mechanism.

We studied five adult giant Galápagos tortoises Geochelone elephantopus (mean mass=142 kg; range= 103–196 kg). Walking speed was extremely slow (0.16±0.052 m s–1; mean ± 1 s.d.). The fluctuations in kinetic energy(8.1±3.98 J stride–1) were only one-third as large as the fluctuations in gravitational potential energy (22.7±8.04 J stride–1). In addition, these energies fluctuated nearly randomly and were only sporadically out of phase. Because of the dissimilar amplitudes and inconsistent phase relationships of these energies, tortoises conserved little mechanical energy during steady walking, recovering only 29.8±3.77% of the mechanical energy (range=13–52%). Thus, giant Galápagos tortoises do not utilize effectively an inverted-pendulum mechanism of energy conservation. Nonetheless, the mass-specific external mechanical work required per distance (0.41±0.092 J kg–1 m–1) was not different from most other legged animals. Other turtle species use less than half as much metabolic energy to walk as other terrestrial animals of similar mass. It is not yet known if Galápagos tortoises are economical walkers. Nevertheless,contrary to biomechanical convention, poor inverted-pendulum mechanics during walking do not necessarily correspond to high mechanical work and may not result in a high metabolic cost.
The effect of ball size variation on nonlinear vibrations associated with ball bearings
Authors: Harsha S P
Published: March 2005

An analytical model to predict nonlinear dynamic responses in a rotor bearing system due to ball size variation has been developed. In the analytical formulation the contacts between the rolling elements and the races are considered as nonlinear springs, whose stiffnesses are obtained using Hertzian elastic contact deformation theory. The governing differential equations of motion are obtained using Lagrange's equations. The implicit type numerical integration technique Newmark-β with the Newton-Raphson method is used to solve the nonlinear differential equations iteratively. A computer program is developed to simulate the effects of ball size variations. Results are presented in the form of fast fourier transformation and Poincarè maps. The highest radial vibrations due to ball size variation are at a speed of the number of balls times the cage speed (ω =kωc Hz). The other vibrations due to ball size variation also occur at VC ± kωcage, where k is a constant.
Influence of anti-dive and anti-squat geometry in combined vehicle bounce and pitch dynamics
Authors: Azman M , Rahnejat H , King P D , Gordon T J
Published: March 2005

The paper presents a six-degree-of-freedom (6-DOF) multi-body vehicle model, including realistic representation of suspension kinematics. The suspension system comprises anti-squat and anti-dive element. The vehicle model is employed to study the effect of these features upon combined bounce and pitch plane dynamics of the vehicle, when subjected to bump riding events. The investigations are concerned with a real vehicle and the numerical predictions show reasonable agreement with measurements obtained on an instrumented vehicle under the same manoeurves.
Modal description of vibratory behaviour of structures using fuzzy membership functions
Authors: Khoshnoud Farbod , Khoshnoud Farhoud , Esat I I
Published: March 2005

A method is developed to model vibratory systems in terms of their modal shapes estimated by fuzzy membership functions and updated by use of frequency response functions. In this method, fuzzy output membership functions are introduced based on ‘guessed’ mode shapes of the system. The approximate mode shapes can be estimated as they partially depend on the boundary conditions. The fuzzy membership functions are then updated using experimental modal analysis method which is used in refining ‘fuzzy mode shapes’. The fuzzy mode shapes are then interpolated with respect to geometry and frequency, giving full behaviour description of the system in frequency domain using fuzzy neural network. Although the method proposed is general in this paper, the case study is based on a simple beam. Two inputs of the fuzzy model are sampling positions on the beam and frequency. The natural frequencies of the system were found by experimental tests. Mode shape or deflection of the beam is introduced by zero, medium, large and positive and negative terms. These mode shapes are modified by using the data from experimental modal analysis. The corresponding magnitude in the fuzzy model is updated by magnitudes from mode shapes from modal testing. A fuzzy neural network is used to determine the mode shape curves from the updated mode shapes. This approach compliments modal analysis and enhances it by incorporating it with fuzzy reasoning. In that respect the proposed method offers two distinct benefits, firstly, the use of fuzzy membership functions provides a means of dealing with uncertainty in measured data and, secondly, it give access to a large repertoire of tools available in fuzzy reasoning field. The procedure proposed in this paper is a novel and has not been done before.
Remarks concerning integrals of normalized quasi-velocities
Authors: Herman P
Published: March 2005

In this paper, the problem of the integrals of normalized quasi-velocities is discussed. Introducing the quasi-velocities known from the robotic literature leads to diagonalization of the manipulator mass matrix in velocity space. It is shown here that, for a two-degree-of-freedom (2-DOF) manipulator, sometimes there exist analytical forms of integrals of normalized quasi-velocities. If the analytical method is not available, then a numerical method is used to calculate integrals of the quasi-velocities. This solution is presented for a 3-DOF three-dimensional DDArm (Direct Drive Arm) robot.
Modelling lubricated revolute joints in multibody mechanical systems
Authors: Flores P , Lankarani H M , Ambrósio J , Claro J C P
Published: March 2005

This work deals with the modelling of lubricated revolute joints in multibody mechanical systems. In most machines and mechanisms, the joints are designed to operate with some lubricant fluid. The high pressures generated in the lubricant fluid act to keep the journal and the bearing apart. Moreover, the thin film formed by lubricant reduces friction and wear, provides load capacity and adds damping to dissipate undesirable mechanical vibrations. In the dynamic analysis of journal-bearings, the hydrodynamic forces, which include both squeeze and wedge effects, produced by the lubricant fluid oppose the journal motion. These forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds' equation written for the dynamic regime. The hydrodynamic forces are nonlinear functions of journal centre position and velocity relative to the bearing centre. In a simple way, the hydrodynamic forces built up by the lubricant fluid are evaluated from the state of variable of the system and included into the equations of motion of the mechanical system. Results for an elementary slider-crank mechanism, in which a lubricated revolute joint connects the connecting rod and slider, are used to discuss the assumptions and procedures adopted.
Cooperative Enhancement of Two-photon Absorption of Multibranched Compounds with Vinylenes Attaching to the s-Triazine Core
Authors: Cui Yue-Zhi , Fang Qi , Xue Gang , Xu Gui-Bao , Yin Lei , Yu Wen-Tao
Published: March 2005

Two series of multibranched compounds with vinylenes attaching to the s-triazine core have been synthesized. The two-photon absorption cross section (σ) increases significantly as the branch number increases, with the ratios of σ between one-, two-, and three-branched compounds being 1.0:3.3:7.0 for series A and 1.0:3.7:7.0 for series B respectively, indicating remarkable cooperative enhancement.
Mild and moderate varicose vein reflux does not deteriorate over time
Authors: Dix F P , Boyle S , McCollum C N
Published: March 2005

Objective: To prioritize varicose vein (VV) waiting lists, superficial venous reflux was timed in patients with primary VVs using hand-held Doppler (HHD) and classified as 'severe' (≤4s), 'moderate' (>4; ≤6s) or 'mild' (>6s). Only patients with severe reflux were offered surgery. The progression of reflux in those not offered surgery was investigated over two years.

Methods: Patients seen in the VV clinic between November 1999 and October 2000 with reflux ≥4s were re-assessed two years later. Reflux was timed at the saphenofemoral (SFJ) and saphenopopliteal (SPJ) junctions using HHD. Patients completed a basic symptom questionnaire. The severity of VVs and skin changes of venous insufficiency were graded.

Results: In all, 38/54 patients attended for review at two years. There were 44 limbs with 48 sites of reflux, 38 at the SFJ and 10 at the SPJ. Reflux improved at 27 sites, remained the same at five and deteriorated at 16. Reflux became 'severe' in eight limbs, but only four patients requested surgery. Median (interquartile range) reflux time was 6.0 (5–6)s in 1999–2000 and 7.0 (4–10)s in 2002 ( P = 0.13). Median symptom scores for aching and the severity of VV remained unchanged. The cosmetic appearance of VV and skin signs of venous insufficiency significantly improved ( P < 0.01).

Conclusions: Mild and moderate reflux did not deteriorate in most VV patients. HHD may be a useful adjunct to grade venous reflux and prioritize patients for VV surgery.
The association between the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 gene and deep venous thrombosis in young people
Authors: Mansilha A , Araújo F , Severo M , Sampaio S M , Toledo T , Henriques I , Albuquerque R
Published: March 2005

Objective: To evaluate the association between the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene and deep venous thrombosis (DVT) in young people.

Methods: Prevalence of the 4G/5G polymorphism was investigated using DNA analysis in a population of 81 consecutive and unrelated patients with an objectively documented first episode of DVT under 40 years old and in a control group of 88 healthy subjects.

Results: The frequency of genotypes among patients was 0.27 4G/4G, 0.49 4G/5G and 0.23 5G/5G, corresponding to a frequency of 0.52 for the 4G allele. In the control group the results were, respectively, 0.24, 0.44 and 0.32, corresponding to a frequency of 0.46 for the 4G allele. The odds ratio (OR) for homozygous 4G genotype was 1.5 (95% confidence interval: 0.7–3.6), which was not statistically significant ( P = 0.51).

Conclusion: In this study, the 4G/5G polymorphism in the promoter of the PAI-1 gene, including the homozygous 4G genotype, was not associated with a significantly increased risk of DVT in young people.
Haemodynamic surgery for varicose veins: surgical strategy
Authors: Juan J , Escribano J M , Criado E , Fontcuberta J
Published: March 2005

The haemodynamic approach for the treatment of varicose veins is a minimally invasive, non-ablative procedure that preserves the saphenous vein. The strategic principles for the implementation of this treatment include fragmentation of the venous pressure column, interruption of the venous segments where reflux originates, preservation of the superficial venous outflow channels to allow adequate drainage of the residual superficial system, and excision of the superficial varicose veins that remain undrained. This treatment modality requires a thorough understanding of the haemodynamic and anatomic rationale on which haemodynamic surgery is construed to tailor a treatment plan individually for each patient. The principles for the implementation of this strategy for the treatment of varicose veins are described here and the results are discussed.
Discriminating Lamprey Species Using Multilocus Microsatellite Genotypes
Authors: Filcek Kristine B. , Gilmore Stacy A. , Scribner Kim T. , Jones Michael L.
Published: March 2005

Efforts to manage the invasive sea lamprey Petromyzon marinus in the Great Lakes have greatly reduced the species' abundance and distribution. The methods employed have also affected the abundance and distribution of species that are native to the Great Lakes basin, including the American brook lamprey Lampetra appendix (also known as Lethenteron appendix), the northern brook lamprey Ichthyomyzon fossor, and the silver lamprey I. unicuspis. Discrimination among the four species based on the phenotypic characteristics of larvae is difficult, making accurate assessments of their abundance, recruitment, and distribution within streams problematic. Given growing interest in the conservation of native species and the effects of sea lamprey controls, an alternative method of identification is warranted. Owing to species-specific fixed differences in alleles, microsatellite loci were extremely useful in discriminating lamprey species. Samples of each species were analyzed with respect to seven microsatellite loci. Based on the genetic differences among individuals, we were able to separate samples of each species by genus. In addition, brook and silver lampreys could be identified to species with high probability. Assignment tests of Ichthyomyzon species revealed a confidence of assignment of at least 0.95 for 96.4% of all individuals. Using a single locus, we examined larvae of a single cohort when larval size was consistent with age-0 (n = 449) and age-1 (n = 1,203) status across five Lake Superior streams. When genotyped using a discriminating locus, it was found that 57.9% of those that were age 0 and 16.8% of those that were age 1 were incorrectly identified based on phenotype. Within one stream, we observed significant differences in the distributions of native and sea lamprey larvae across upstream, middle, and downstream regions, suggesting that there are species differences in spawning sites and focal areas of larval recruitment. Molecular methods will prove to be a useful tool in assessing native species' abundance and distribution and can direct management to the application of alternative control methods.
Effectiveness of Strobe Lights for Reducing Juvenile Salmonid Entrainment into a Navigation Lock
Authors: Johnson Peter N. , Bouchard Kyle , Goetz Frederick A.
Published: March 2005

Strobe lights effectively reduced fish entrainment into the large locks at the Hiram M. Chittenden Locks Project in Seattle, Washington. The anadromous salmonids of the Lake Washington system, Chinook salmon Oncorhynchus tshawytscha, coho salmon O. kisutch, sockeye salmon O. nerka, and steelhead O. mykiss, must pass through these locks en route to the Pacific Ocean. Of the available downstream passage routes, use of the large lock-filling culverts is considered the most harmful to fish because of potential entrainment contact with the barnacle-lined culvert walls. We evaluated the effectiveness of strobe lights for displacing fish from in front of the culverts and for reducing entrainment during large lock fills. From 3 May to 14 June 2002, we used split-beam hydroacoustics to estimate the number of fish entrained during paired light-on-light-off treatments. Results indicated that strobe lights significantly reduced (75%) entrainment, an estimated 1,427 fish being entrained during lights-off treatments versus 350 during lights-on. Effectiveness was also supported by t-tests on individual range strata in front of the culvert entrances: 1-m strata from the floor to 4 m above the floor indicated significant reduction in number of entrained fish during the lights-on treatments. Using strobe lights for reducing culvert entrainment probably increases juvenile salmonid survival through the locks.
High Lipoprotein(a) Levels and Small Apolipoprotein(a) Size Prospectively Predict Cardiovascular Events in Dialysis Patients
Authors: Longenecker Craig J. , Klag Michael J. , Marcovina Santica M. , Liu Yong-Mei , Jaar Bernard G. , Powe Neil R. , Fink Nancy E. , Levey Andrew S. , Coresh Josef
Published: March 2005

Lipoprotein(a) [Lp(a)] levels are increased in dialysis patients, suggesting that they may play a role in the elevated atherosclerotic cardiovascular disease (ASCVD) risk in this population. Few prospective studies of Lp(a) level, apolipoprotein(a) [apo(a)] size, and ASCVD have been performed in the dialysis population. An inception cohort of 833 incident dialysis patients were followed prospectively. Baseline Lp(a) was measured by apo(a) size-independent ELISA and apo(a) size by Western blot after SDS-agarose gel electrophoresis. A combined prospective nonfatal and fatal ASCVD end point included myocardial infarction, coronary revascularization, cerebrovascular accident, carotid endarterectomy, peripheral revascularization, gangrene, or limb amputation. Survival analyses were performed with adjustment for baseline demographics, comorbid conditions, ASCVD risk factors, albumin, lipids, and C-reactive protein. Median follow-up was 27.4 mo, with 297 ASCVD events, 130 non-ASCVD deaths, and seven losses to follow-up over 1649 person-years. In multivariate Cox regression models, both high Lp(a) concentration (≥53 nmol/L) and low molecular weight (LMW) apo(a) isoforms (≤22 Kringle-IV repeats) predicted ASCVD events (relative hazard [RH] = 1.38,

P

= 0.02; RH = 1.58,

P

< 0.0005, respectively). In models that included both Lp(a) concentration and apo(a) size, only apo(a) size remained associated with ASCVD. Among those with both LMW apo(a) and Lp(a) level >123 nmol/L, the relative hazard (RH) of ASCVD was 1.73 (

P

< 0.0005), compared with high molecular weight apo(a) and Lp(a) level <123 nmol/L. No interactions by age, race, gender, diabetes, or ASCVD were present. Both LMW apo(a) size and high Lp(a) level predict ASCVD risk in dialysis patients, but the association of ASCVD with LMW isoforms is stronger than the association with high Lp(a) concentration.
Die intermolekulare Pauson‐Khand‐Reaktion
Authors: Gibson Susan E. , Mainolfi Nello
Published: March 2005

Fünfgliedrige Kohlenstoffringe sind wichtige Bausteine beim Aufbau vieler biologisch aktiver Moleküle, und insbesondere substituierte Cyclopentenone, z. B. Cyclopentenonprostaglandine, weisen eine charakteristische biologische Aktivität auf. Für die Synthese solcher Verbindungen ist die Pauson‐Khand‐Reaktion mit ihrer hohen Effizienz und Atomökonomie eine der Methoden der Wahl. Anwendungen der intermolekularen Pauson‐Khand‐Reaktion waren stets durch die geringe Reaktivität und Selektivität der Alkenkomponente eingeschränkt, auch wenn die Reaktion ursprünglich in dieser intermolekularen Form entdeckt worden war. Speziell in den vergangenen drei Jahren wurden größere Anstrengungen unternommen, um die Einsatzmöglichkeiten der Pauson‐Khand‐Reaktion zu erweitern. Wir geben hier einen umfassenden und bewertenden Überblick über die intermolekulare Pauson‐Khand‐Reaktion auf der Grundlage von Reaktivitätscharakteristiken der Alkenkomponenten. Insbesondere versuchen wir, durch Identifizierung der Reaktivitätsmuster unterschiedlicher Alkenklassen Aufschluss über Erfolge und Misserfolge auf diesem Gebiet zu erlangen.
Crystallization kinetics and tensile modulus of blends of metallocene short‐chain branched polyethylene with conventional polyolefins
Authors: Peng Ya , Zhang Qin , Du Rongni , Fu Qiang
Published: March 2005

In this study, blends of metallocene short‐chain branched polyethylene (SCBPE) with low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), polystyrene (PS), ethylene–propylene–diene monomer (EPDM), and isotactic polypropylene (iPP) were prepared in weight proportions of 80 and 20, respectively. The crystallization behaviors of these blends were studied with polarized light microscopy (PLM) and differential scanning calorimetry. PLM showed that SCBPE/LDPE, SCBPE/HDPE, and SCBPE/EPDM formed band spherulites whose band widths and sizes were both smaller than that of pure SCBPE. No spherulites were observed, but tiny crystallites were observed in the completely immiscible SCBPE/PS, and the crystallites in SCBPE/iPP became smaller; only irregular spherulites were seen. The crystallization kinetics and mechanical properties of SCBPE were greatly affected by the second polyolefin but in different way, depending on the phase behavior and the moduli of the second components. SCBPE may be phase‐miscible in the melt with LDPE, HDPE, and EPDM but phase‐separated during crystallization. A big change in the crystal morphology and crystallization kinetics existed in the SCBPE/iPP blend. The mechanical properties of the blends were also researched with dynamic mechanical analysis (DMA). DMA results showed that the tensile modulus of the blends had nothing to do with the phase behavior but only depended on the modulus of the second component. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1816–1823;2005
Effect of inorganic fillers in binary processing aids on the rheology of a metallocene linear low‐density polyethylene
Authors: Liu Xiaolong , Xie Meiju , Li Huilin
Published: March 2005

Inorganic fillers including porous diatomite, flaky talc, and spherical calcium carbonate were blended with polyethylene glycol (PEG) to prepare binary processing aids, and the effect of varied binary processing aids on the melt flow properties and extrudates distortion of a metallocene linear low‐density polyethylene (mLLDPE) was studied. It was found that the binary processing aids exhibit better effect on viscosity reduction of mLLDPE than that obtained when PEG was added alone. The morphology of inorganic fillers influences the effect of binary processing aids. The diatomite/PEG binary processing aid shows the most noticeable effect, followed by the talc/PEG binary processing aid, and then the calcium carbonate/PEG binary processing aid. The influence of particle size of the diatomite on the effectiveness of the diatomite/PEG binary processing aid was also studied. The mechanism for the improved effect of binary processing aids on reducing viscosity of mLLDPE was proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1824–1829;2005
Soluble and conductive copolymers from 1‐(hydroxyalkyl) pyrroles
Authors: Kişkan Bariş , Akar Ahmet , Kızılcan Nilgün , Ustamehmetoğlu Belkıs
Published: March 2005

1‐Substituted pyrroles such as 1‐(hydroxymethyl)pyrrole, 1‐(3‐hydroxypropyl) pyrrole, 1‐H‐1‐pyrrolylmethyl 4‐methyl‐1‐benzenesulfonate, 1‐H‐1‐pyrrolylpropyl 4‐methyl‐1‐benzenesulfonate, and 1‐H‐pyrrolylmethyloctanoate were synthesized and oxidative polymerized and copolymerized with pyrrole by using (NH4)2Ce(NO3)6 and FeCl3. Some of the copolymers were slightly soluble in DMF and DMSO. The products were characterized by FTIR, 1H‐NMR, and four‐point probe conductivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1830–1834, 2005
Novel, positively charged membrane from a blending, crosslinking, and coagulation procedure
Authors: Cheng Bowen , Wang Yong , Du Qiyun
Published: March 2005

A novel, positively charged membrane was prepared through a blending, crosslinking, and coagulation procedure in which poly(N,N‐dimethylaminoethyl methacrylate) (PDM) and polyacrylonitrile (PAN) were used as the functional and substrate component, respectively. Because 1,4‐dibromobutane (DBT) was used as the crosslinker and quaternizing agent, PDM was crosslinked and quaternized simultaneously. The effects of PDM content, polymer concentration, and additive dosage of the casting solution on the membrane performances are discussed in detail, and differences between the PAN membrane, PDM/PAN blend membrane, and crosslinked PDM/PAN blend membrane are also discussed. We also studied the adsorption behaviors of the membranes to a positively charged dye and a negatively charged dye. Environmental scanning electron microscopy observation showed that the resulting positively charged membrane from such a blending, crosslinking, and coagulation procedure possessed a unique and uniform structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1847–1854, 2005
Compositional and configurational sequence determination of methacrylonitrile–vinylidene chloride copolymers by nuclear magnetic resonance spectroscopy
Authors: Brar A. S. , Pradhan D. R. , Hooda Sunita
Published: March 2005

Methacrylonitrile–vinylidene chloride (M/V) copolymers of different composition were prepared by bulk polymerization using benzoyl peroxide as an initiator under nitrogen atmosphere in a sealed tube. The copolymer composition was determined from quantitative 13C[1H] NMR spectra. The reactivity ratios for M/V copolymers obtained from a linear Kelen–Tudos method and nonlinear error‐in‐variables method are rM = 2.47 ± 0.14, rV = 0.40 ± 0.02, and rM = 2.43, rV = 0.39, respectively. The complete spectral assignment in term of compositional and conformational sequences of these copolymers were done with the help of distortionless enhancement by polarization transfer, two‐dimensional heteronuclear single‐quantum coherence spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1865–1874, 2005
A comparison of the oxidizing ability of polystyrene‐supported linear and cyclic polyoxyethylene bound permanganates
Authors: Chacko Asha , Devi Renuka , Abraham Susan , Mathew Beena
Published: March 2005

The grafting of linear and cyclic polyoxyethylenes into DVB‐crosslinked chloromethylpolystyrene was carried out by treating with polyethyleneglycol (PEG600). The complexations of crosslinked polystyrene‐supported linear and cyclic polyoxyethylene with permanganate functions were carried out. With this reagent, primary alcohols and secondry alcohols were converted to aldehydes and ketones and aldehyde to acid. The polymer acts as a reservoir of permanganate functions and releases them slowly as the substrates are being used up. The effect of solvent, molar excess of reagent, time, and temperature on oxidation behavior were investigated by choosing benzoin to benzil conversion as the model reaction. The linear polymeric reagent has greater reactivity than the cyclic polymer due to the greater availability of the reactive sites in the linear polymer than the cyclic polymer. Polymeric reagent could be used in excess to get a good yield without causing any separation problems and over oxidation products. The reagents have advantages of easy separation, regeneration and reuse. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1897–1905, 2005
Processing and mechanical properties of organic filler–polypropylene composites
Authors: Mantia F. P. La , Morreale M. , Ishak Z. A. Mohd
Published: March 2005

The addition of organic fillers into thermoplastic polymers is an interesting issue, which has had growing consideration and experimentation during the last years. It can give rise to several advantages. First, the cost of these fillers is usually very low. Also, the organic fillers are biodegradable (thus contributing to an improved environmental impact), and finally, some mechanical and thermomechanical properties can be enhanced. In this study, the effect of the addition of different organic fillers on the mechanical properties and processability of an extrusion‐grade polypropylene were investigated. The organic fillers came from natural sources (wood, kenaf, and sago) and were compared to short glass fibers, a widely used inorganic filler. The organic fillers caused enhancements in the rigidity and thermomechanical resistance of the matrix in a way that was rather similar to the one observed for the inorganic filler. A reduction in impact strength was observed for both types of fillers. The use of an adhesion promoter could improve their behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1906–1913, 2005
Thermal and structural properties of poly(vinyl alcohol) doped with hydroxypropyl cellulose
Authors: El‐Zaher N. A. , Osiris W. G.
Published: March 2005

The growth and importance of medical and related health care and hygiene textile sectors are attributed to the improvement and innovations in both textile technology and medical procedures. The aim of this study was to examine some of the structural properties of pure poly(vinyl alcohol) (PVA) and hydroxypropyl cellulose (HPC) doped PVA of different weight percentages. This will lead to the choice of the optimum conditions suited for specific medical and surgical applications for which textile materials are currently used. Thermogravimetry was used to develop an instrumental system for the study of thermal stability and for identification of the individual components of several polymer blends. Derivative thermogravimetry provided clear information and distinguished between different generic types. Also, differential scanning calorimetry and its derivatives gave accurate values of glass‐transition temperature and melting temperature and gave detailed features of the steps of weight loss and changes in the heat of fusion. The X‐ray diffraction technique was used to determine the crystallinity/amorphosity ratio and the change in crystallite size at different dopant concentrations. The effect of doping with HPC on PVA structure was studied with spectrophotometric analyses. Variations in the group coordination in the IR region were followed. The data obtained indicated that measurable and remarkable changes in the thermal stability of PVA occurred at different doping concentrations. This may have been because the diffusion of dopant caused structural changes in the polymer matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1914–1923, 2005
Photocuring systems composed of vinyl ether terminated polyurethane and maleate
Authors: Zeng Zhaohua , Zhang Liping , Yang Jianwen , Chen Yonglie
Published: March 2005

Vinyl ether terminated polyurethane (VE–PU) was synthesized in this investigation. The copolymerization behavior of VE–PU and dimethyl maleate (DMA) was investigated by 13C‐NMR. It was found that the copolymerization of VE–PU and DMA is of alternating composition, and no homopolymer structure was found in the polymerization products. Differential photocalorimetry results show that, when the monomer feed molar ratio was close to 1 : 1, the total conversion increased, whereas the effective conversion decreased. The rate of copolymerization was affected by oxygen and reaction temperature and depended on the square root of both the initiator concentration and the light intensity. The rheological properties of VE–PU/DMA system were also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1930–1935, 2005
Comparison of the pervaporation separation of a water–acetonitrile mixture with zeolite‐filled sodium alginate and poly(vinyl alcohol)–polyaniline semi‐interpenetrating polymer network membranes
Authors: Naidu B. Vijaya Kumar , Bhat S. D. , Sairam M. , Wali A. C. , Sawant D. P. , Halligudi S. B. , Mallikarjuna N. N. , Aminabhavi T. M.
Published: March 2005

The pervaporation (PV) separation performance of ZSM‐5‐ and Na‐Y‐type zeolite‐filled sodium alginate (NaAlg) membranes were compared with those of pure NaAlg and semi‐interpenetrating polymer network (semi‐IPN) membranes of poly(vinyl alcohol) (PVA) with polyaniline (PANI) for the dehydration of acetonitrile. The PV separation characteristics of the zeolite‐filled membranes showed a dependence on the nature of the zeolites. The variation of the acidity function of the ZSM‐5 zeolite had an influence on the flux and selectivity of the membranes when compared to unfilled membranes. The crosslinked membranes were characterized by differential scanning calorimetry, X‐ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Increasing the PANI content of the semi‐IPN network increased the separation selectivity. Among the NaAlg membranes, the plain NaAlg membrane showed the highest selectivity of 414 at 30 mass % water in the feed mixture, whereas the Na‐Y‐ and ZSM‐5 (40)‐filled NaAlg membranes exhibited much lower values of selectivity, that is, 7.3 and 4.3, respectively for 30 mass % water in the feed. When the flux and selectivity data of ZSM‐5 (250)‐filled NaAlg membranes were compared with that of Na‐Y‐ or ZSM‐5 (40)‐filled NaAlg membranes, a noticeable increase in the selectivity for the ZSM‐5 (250)‐filled NaAlg membrane was observed, but a somewhat comparable flux was observed compared to the plain NaAlg membrane. For the first time, PANI was polymerized with PVA to yield a semi‐IPN. The total flux and water flux increased systematically, whereas the selectivity decreased greatly from 251.87 to 5.95 with increasing amounts of water in the feed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1968–1978, 2005
Carbon nanotube core–polymer shell nanofibers
Authors: Liu Jing , Wang Tong , Uchida Tetsuya , Kumar Satish
Published: March 2005

Single‐walled carbon nanotube (SWNT)/poly(methyl methacrylate) and SWNT/polyacrylonitrile composite nanofibers were electrospun with SWNT bundles as the cores and the polymers as the shells. This was a novel approach for processing core (carbon nanotube)–shell (polymer) nanofibers. Raman spectroscopy results show strain‐induced intensity variations in the SWNT radial breathing mode and an upshift in the tangential (G) and overtone of the disorder (G′) bands, suggesting compressive forces on the SWNTs in the electrospun composite fibers. Such fibers may find applications as conducting nanowires and as atomic force microscopy tips. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1992–1995, 2005
Membrane fouling in a membrane bioreactor (MBR): Sludge cake formation and fouling characteristics
Authors: Ping Chu Hiu , Li Xiao‐yan
Published: March 2005

A submerged membrane bioreactor (MBR) with a working volume of 1.4 L and a hollow fiber microfiltration membrane was used to treat a contaminated raw water supply at a short hydraulic retention time (HRT) of ∼1 h. Filtration flux tests were conducted regularly on the membrane to determine various fouling resistances, and confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were employed to characterize the biofouling development and sludge cake formation on the membrane. The experimental results demonstrate that the MBR is highly effective in drinking water treatment for the removal of organic pollutants, ammonia, and UV absorbance. During the MBR operation, the fouling materials were not uniformly distributed on the entire surface of all of the membrane fibers. The membrane was covered partially by a static sludge cake that could not be removed by the shear force of aeration, and partially by a thin sludge film that was frequently washed away by aeration turbulence. The filtration resistance coefficients were 308.4 × 1011 m−1 on average for the sludge cake, 32.5 × 1011 m−1 on average for the dynamic sludge film, and increased from 10.5 × 1011 to 59.7 × 1011 m−1 for the membrane pore fouling after 10 weeks of MBR operation at a filtration flux of 0.5 m3/m2·d. Polysaccharides and other biopolymers were found to accumulate on the membrane, and hence decreased membrane permeability. More important, the adsorption of biopolymers on the membrane modified its surface property and led to easier biomass attachment and tighter sludge cake deposition, which resulted in a progressive sludge cake growth and serious membrane fouling. The sludge cake coverage on the membrane can be minimized by the separation, with adequate space, of the membrane filters, to which sufficient aeration turbulence can then be applied. © 2005 Wiley Periodicals, Inc.
Ethnic hierarchies, ethnic prejudice, and social dominance orientation
Authors: Snellman Alexandra , Ekehammar Bo
Published: March 2005

Previous research in multi‐ethnic societies has shown that people rank, or form hierarchies of, the ethnic groups on the basis of social distance. Based on self‐report data from a community sample (N = 150 non‐psychology students), this study examined (1) the correspondence of ratings and rankings of six ethnic target groups among various subgroups of participants (Swedish and immigrant men and women), and (2) the relationship of inclination to ethnic ranking with ethnic prejudice and social dominance orientation. In accord with our hypotheses, the results disclosed that (1) irrespective of gender and ethnic origin, the various subgroups of participants ranked and formed similar hierarchies of the six ethnic target groups, and (2) people's inclination to ethnic ranking showed significant correlations with their ethnic prejudice as well as social dominance orientation. Copyright © 2005 John Wiley & Sons, Ltd.
An exploration of the interplay between psychological sense of community, social identification and salience
Authors: Obst Patricia L. , White Katherine M.
Published: March 2005

Past research indicates that there is a strong relationship between the constructs of psychological sense of community (PSOC) and social identification. The current study draws on data (N = 219) examining participants' membership in a number of different communities to present an examination of the relationship between these constructs. In particular, the study examines the relative strength of the separate aspects of social identification (based on Cameron's 2004, Three Factor Model of Social Identification) as predictors of overall PSOC, accounting for situational salience. Results indicate that Ingroup Ties is consistently the strongest predictor of PSOC and that the strength of Ingroup Affect and Centrality alter according to the group or community context. The theoretical implications of these results are discussed in terms of the interplay and overlap of these important community processes. Copyright © 2005 John Wiley & Sons, Ltd.
A qualitative study of adaptation to the euro in the Republic of Ireland: I. attitudes, the ‘euro illusion’ and the perception of prices
Authors: Ranyard Rob , Burgoyne Carole B. , Saldanha Gabriela , Routh David A.
Published: March 2005

This is the first of two reports of a study using semi‐structured, in‐depth interviews to explore the current and recollected experiences of Irish people for the period before, during, and after the introduction of euro notes and coins (1 January 2002). Twenty‐four adults, 12 males and 12 females, covering a range of ages and educational attainment, were interviewed between October 2002 and February 2003. We found that most had welcomed the new currency initially, though some had felt less positive about it, whilst current experiences were more mixed. People's explanations for their attitudes seemed to focus more on the economic and practical aspects of currency change rather than symbolic meanings. Initially, most had experienced a euro illusion (prices in euros seeming to be more expensive than in punts). However, for most, the strength of the illusion appeared to diminish quite quickly. Nonetheless, current prices were believed to be higher, and many respondents attributed this either directly or indirectly to the change of currency. Although independent evidence found that there had been price increases in certain sectors, it was concluded that perceived price rises were, in part, illusory, and driven by expectations and selective price monitoring. Copyright © 2005 John Wiley & Sons, Ltd.
Social representations of organ donors and non‐donors
Authors: Lauri Mary Anne , Lauri Josef
Published: March 2005

This paper illustrates the empirical investigation of social representations by means of photographs as stimulus material and the technique of correspondence analysis to study the resulting data. The research was part of a campaign carried out to promote organ donation in Malta. The study tries to find out whether a public communication campaign could change perceptions. Five focus groups were held before the campaign and another five, two months after the campaign. Part of the data collected through these focus groups was analysed using correspondence analysis. The results showed that before the campaign, donors were generally perceived to be either young or important people or public personalities. After the campaign, donors were perceived more to be ordinary family people, educated, generous and religious. On the other hand, before the campaign, non‐donors were seen as conservative, uncouth and uncaring, whereas after the campaign non‐donors were generally perceived to be older, uninformed and uneducated people. Copyright © 2005 John Wiley & Sons, Ltd.
Detection of analytical bias when comparing two or more measuring methods
Authors: de Castro Mário , Galea‐Rojas Manuel , Bolfarine Heleno , de Castilho Márcio V.
Published: March 2005

The main goal of this paper is to consider maximum likelihood inference for models used in the detection of analytical bias in the comparison of two or more methods of measurement. We embrace a functional errors‐in‐variables regression model with an EM‐type algorithm for computing maximum likelihood estimates and to obtain consistent estimators for the asymptotic variance of the maximum likelihood estimators, which seems not to be found in the literature. Wald‐type statistics are proposed for testing hypotheses related to the bias of the analytical methods with the asymptotic chi‐square distribution which guarantees correct asymptotic significance levels. Some approaches specific for the two‐methods comparison problem are not directly extendable to this more general situation. Results of simulation studies and an application to a real data set are also reported. Copyright © 2005 John Wiley & Sons, Ltd.
A comparison of methods for analysing regression models with both spectral and designed variables
Authors: Jørgensen Kjetil , Segtnan Vegard , Thyholt Kari , Næs Tormod
Published: March 2005

In many situations one performs designed experiments to find the relationship between a set of explanatory variables and one or more responses. Often there are other factors that influence the results in addition to the factors that are included in the design. To obtain information about these so‐called nuisance factors, one can sometimes measure them using spectroscopic methods. The question then is how to analyze this kind of data, i.e. a combination of an orthogonal design matrix and a spectroscopic matrix with hundreds of highly collinear variables. In this paper we introduce a method that is an iterative combination of partial least squares (PLS) and ordinary least squares (OLS) and compare its performance with other methods such as direct PLS, OLS and a combination of principal component analysis and least squares. The methods are compared using two real data sets and using simulated data. The results show that the incorporation of external information from spectroscopic measurements gives more information from the experiment and lower variance in the parameter estimates. We also find that the introduced algorithm separates the information from the spectral and design matrices in a nice way. It also has some advantages over PLS in showing lower bias and being less influenced by the relative weighting of the design and spectroscopic variables. Copyright © 2005 John Wiley & Sons, Ltd.
Extensions to peak alignment using reduced set mapping: classification of LC/UV data from peptide mapping
Authors: Magnus Åberg K. , Torgrip Ralf J. O. , Jacobsson Sven P.
Published: March 2005

Peak alignment using reduced set mapping (PARS) is extended with a new baseline approximation and a new dendrogram alignment scheme, which is designed to avoid the issue of selecting a target chromatogram for the alignment. Two data sets with LC/UV data are studied and it is shown that peak alignment with PARS increases the class separation substantially in the principal component score space. The results indicate that it is possible to use PARS for calibration transfer of multivariate models of chromatographic data. Copyright © 2005 John Wiley & Sons, Ltd.