bluuebunny/crossref_metadata_2025_split 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

SUMMARYWe 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

SUMMARYAnimals 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 &lt;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.
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

Abstract
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.
Discriminating Lamprey Species Using Multilocus Microsatellite Genotypes
Authors: Filcek Kristine B. , Gilmore Stacy A. , Scribner Kim T. , Jones Michael L. 
Published: March 2005

Abstract
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

Abstract
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.
Die intermolekulare Pauson‐Khand‐Reaktion
Authors: Gibson Susan E. , Mainolfi Nello 
Published: March 2005

AbstractFünfgliedrige 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

AbstractIn 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

AbstractInorganic 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

Abstract1‐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

AbstractA 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

AbstractMethacrylonitrile–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

AbstractThe 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

AbstractThe 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

AbstractThe 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