bluuebunny/crossref_metadata_2025_split huggingface dataset:
Giant wood spider Nephila pilipes alters silk protein in response to prey variation
Authors: Tso I-Min , Wu Hsuan-Chen , Hwang In-Ru 
Published: March 2005

SUMMARY
Recent studies have demonstrated that orb-weaving spiders may alter web structures, foraging localities or silk output in response to prey variations. In this study we conducted field surveys and food manipulations to examine whether orb-weaving spiders may also adjust the protein of silk to prey variations. A comparison of dragline silks collected from nine giant wood spider Nephila pilipes populations in Taiwan showed a spatial variation. The percentage of all amino acids (except alanine and glycine)exhibited significant differences among populations. A survey of prey composition also revealed a significant spatial variation among N. pilipes populations. To determine whether prey variation was responsible for silk protein variation, we fed N. pilipes with different types of prey (dipteran vs orthopteran) then compared the percentage of five major dragline amino acids and secondary structures. The results showed that dragline of N. pilipes fed with orthopteran prey contained significantly higher proline and glutamine but lower alanine. Congruent with this result were those from FTIR spectroscopy, which showed that dragline of N. pilipes fed with crickets exhibited significantly higher percentage of proline- and glutamine-containing β turns, and lower percentage of alanine-containing β sheet structures. Since the results of feeding manipulations showed that diet significantly affected the compositions of dragline silks, the observed spatial variation seemed to reflect the different types of prey these spiders had consumed. Results of this study thus indicated that orb-weaving spiders can alter dragline protein in response to prey variations.
Direct calorimetry reveals large errors in respirometric estimates of energy expenditure
Authors: Walsberg Glenn E. , Hoffman Ty C.M. 
Published: March 2005

SUMMARY
Knowledge of animal energetics is based largely upon indirect calorimetry,which is estimation of metabolic heat production by an organism from measurement of indices such as oxygen consumption or carbon dioxide production. Remarkably, indirect calorimetry has been validated by comparison to direct measurements of metabolic heat production (direct calorimetry) only for highly restricted conditions, primarily with a few species of medium-to-large mammals. Taxa with differing physiologies are little studied. For birds, for example, validations are limited to chickens and waterfowl exposed to mild environmental conditions and typically fasted for prolonged periods. Workers rely upon these restricted validations when studying animals ranging greatly in activity, phylogeny, body size and nutritional status. We tested the accuracy of respirometric estimates of energy expenditure by simultaneous indirect and direct calorimetry in a small mammal (the kangaroo rat Dipodomys merriami Mearns), a small bird (the dove Columbina inca Lesson) and a medium-sized bird (the quail Coturnix communis Linnaeus). We find that conventional respirometric estimates of energy expenditure may incorporate large errors (up to 38%) that are sufficient to call into question generalizations regarding patterns of animal energy use in many studies.
In vivomuscle functionvsspeed I. Muscle strain in relation to length change of the muscle-tendon unit
Authors: Hoyt Donald F. , Wickler Steven J. , Biewener Andrew A. , Cogger Edward A. , De La Paz Kristin L. 
Published: March 2005

SUMMARYThe activity of muscles can be concentric (shortening), eccentric(lengthening) or isometric (constant length). When studying muscle function it is important to know what the muscle fascicles are actually doing because the performance of muscle is strongly influenced by the type of activity: force decreases as a function of shortening velocity during concentric contractions;force produced during eccentric contractions can be stronger than maximum isometric force, and force production is enhanced if a concentric contraction follows an eccentric phase. It is well known that length changes of muscle fascicles may be different from length changes of the overall muscle-tendon unit because of the compliance of the series elasticity. Consequently,fascicles of joint extensor muscles may not undergo eccentric activity even when the joint flexes, but the extent to which this occurs may vary with the compliance of the series elasticity and may differ between species: the vastus lateralis, a knee extensor, shortens when active during trotting in dogs and lengthens in rats. Previous studies of kinematics of trotting in horses have shown that during stance, the elbow extends nearly continuously with a brief period of flexion near mid-stance and the knee exhibits two phases of flexion followed by extension. The lateral triceps (an elbow extensor) has no external tendon but the vastus lateralis has a relatively long external tendon and the fascicles insert on an aponeurosis. Thus, one might expect the relation between fascicle strain and overall length change of the muscle-tendon units to be quite different in these two muscles. In the present study in horses,fascicle length changes of the lateral triceps and vastus lateralis were measured with sonomicrometry and length changes of the muscle-tendon units were estimated from muscle architecture and joint kinematics for four horses trotting on a treadmill at nine speeds. Because the focus of this study was the relation between length changes of the muscle-tendon unit (estimated from kinematics) and length changes in the muscle fascicles, we divided the stance-phase sonomicrometry records into phases that corresponded to the alternating flexion and extension of the joint as indicated by the kinematic records. During its one eccentric phase, the triceps shortened by 0.7±0.4% despite a predicted lengthening of 1%. Similarly, the vastus shortened by 3.7±1.9% when kinematics predicted 3.2% lengthening. During their concentric phases the triceps shortened by 10.6% and the vastus shortened by 8.1%. Strain in the triceps did not change with speed but it did in the vastus. Strain rate increased with speed in both muscles as did the integrated EMG, indicating an increase in the volume of muscle recruited. Thus, despite differences in their architecture and the kinematic patterns of the associated joints, these two joint extensors exhibited similar activity.
The role of mineralized tissue in the buffering of lactic acid during anoxia and exercise in the leopard frogRana pipiens
Authors: Warren Daniel E. , Jackson Donald C. 
Published: March 2005

SUMMARYTo evaluate the role of mineralized tissues of the leopard frog in buffering acid, we analyzed the composition of femur and auditory capsule, the latter of which encloses a portion of the endolymphatic lime sacs, and investigated the extent to which these tissues are involved in buffering lactic acid after 2.5 h of anoxia and 10-19 min of strenuous exercise at 15°C. We analyzed the following tissues for lactate: plasma, heart, liver,gastrocnemius muscle, femur, auditory capsule and carcass. Plasma[Ca2+], [Mg2+], [inorganic phosphate (Pi)],[Na+] and [K+] were also measured. Femur Ca2+, Pi and CO32- compositions were similar to bone in other vertebrates. Auditory capsule had significantly more CaCO3 than femur. Lactate was significantly elevated in all tissues after anoxia and exercise, including femur and auditory capsule. Anoxia increased plasma [Ca2+], [Mg2+], [Pi]and [K+] and had no effect on plasma [Na+]. Exercise increased plasma [Mg2+], [Pi] and [K+] and had no effect on plasma [Ca2+] or [Na+]. The skeleton and endolymphatic lime sacs buffered 21% of the total lactate load during anoxia, and 9% after exercise. The exact contribution of the entire endolymphatic sac system to lactate buffering could not be determined in the present study. We conclude that the mineralized tissues function as buffers during anoxia and exercised induced lactic acidosis in amphibians.
Directionality of the lizard ear
Authors: Christensen-Dalsgaard Jakob , Manley Geoffrey A. 
Published: March 2005

SUMMARYLizards have highly sensitive ears, but most lizard heads are small (1-2 cm in diameter) compared to the wavelengths of sound of frequencies to which they are most sensitive (1-4 kHz, wavelengths 34-8.5 cm). Therefore, the main cues to sound direction that mammals use - binaural time and intensity cues due to arrival-time differences and sound shadowing by the head - will be very small in lizards.The present work shows that acoustical coupling of the two eardrums in lizards produces the largest directionality of any terrestrial vertebrate ear studied. Laser vibrometric studies of tympanic motion show pronounced directionality within a 1.8-2.4 kHz frequency band around the best frequency of hearing, caused by the interference of ipsi- and contralateral inputs. The results correspond qualitatively to the response of a simple middle ear model,assuming coupling of the tympana through a central cavity. Furthermore,observed directional responses are markedly asymmetrical, with a steep gradient of up to 50-fold (34 dB) response differences between ipsi- and contralateral frontal angles. Therefore, the directionality is easily exploitable by simple binaural subtraction in the brain. Lizard ears are the clearest vertebrate examples of directionality generated by tympanic coupling.
Decomposition of Monolayer Coverage on Gold Nanoparticles by UV/ozone Treatment
Authors: Pang Shufeng , Kurosawa Yousuke , Kondo Takeshi , Kawai Takeshi 
Published: March 2005

Abstract
Au nanoparticles, covered with cationic dichain surfactant on the whole surface, were treated with UV/ozone. FT-IR spectra of the Au nanoparticles with bottom-, upper-, and fully covered surfactant monolayers revealed a variable decomposition rate. The sum frequency generation spectra of the treated nanoparticles showed that the surface coverage of gold nanoparticles lose the centrosymmetric structure, implying asymmetric distribution of the protected surfactant molecules. The UV–vis electronic absorption spectra suggested stable nanoparticle monolayer film structure after UV/ozone irradiation.
Syntheses of Novel Indole Lipoic Acid Derivatives and Their Antioxidant Effects on Lipid Peroxidation
Authors: Gurkan A. Selen , Karabay Arzu , Buyukbingol Zeliha , Adejare Adeboye , Buyukbingol Erdem 
Published: March 2005

AbstractThe aim of the study was to examine antioxidant properties of conjugates based on indole and lipoic acid moieties. The design and syntheses of novel indole α‐lipoic acid derivatives were performed. The antioxidant properties of target compounds were investigated using rat liver microsomal, NADPH‐dependent lipid peroxidation inhibition. Some of the target compounds, especially those containing amide linker at position 5 of indole ring, proved to be highly effective in inhibiting lipid peroxidation as compared to α‐lipoic acid.
Magnetic field inhibits isolated lymphocytes' proliferative response to mitogen stimulation
Authors: Roman Adam , Zyss Tomasz , Nalepa Irena 
Published: March 2005

AbstractWe aimed to find out how the exposure of isolated lymphocytes to a pulsed magnetic field (MF) affected their in vitro proliferative response to mitogenic stimulation. Cells were exposed to MF of various intensities (0.3, 0.6, and 1.2 T) at a constant frequency of 30 Hz, for a period of 60, 180, and 330 s. Then, the proliferative response of splenocytes was induced by optimal concentrations of concanavalin A (Con A; mitogenic toward T cells), bacterial lipopolysaccharide (LPS; mitogenic toward B cells), or pokeweed mitogen (PWM; mitogenic toward both populations). We found that the exposure of lymphocytes to the MF profoundly inhibited their proliferative response to mitogens. The suppressive action of the MF on B and T cell proliferation was intensified when a cooperative response of those two lymphocyte populations was simultaneously induced by PWM. The inhibitory effect of MF depended on the exposure time and MF intensity. Prolonged exposure and/or a stronger intensity of the MF weakened its inhibitory influence on the response of lymphocyte to mitogenic stimulation. The data show that an exposure to MF may influence the activity of lymphocytes in their response to mitogenic stimuli. Bioelectromagnetics 26:201–206, 2005. © 2005 Wiley‐Liss, Inc.
On the significance of the time constants of magnetic field sensitivity in animals
Authors: Fuller Mike , Dobson Jon 
Published: March 2005

AbstractA variety of organisms is known to have the ability to transduce and respond to relatively weak magnetic fields, including the earth's field. Though biogenic magnetite has been identified as the transducer in a number of cases with regards to geomagnetic field sensing, the mechanism underlying neurophysiological responses in human studies is not understood. Here we note that the time constants involved in this latter type of field sensitivity are much longer than those in organisms that make use of the earth's magnetic field for navigation. The purpose of this brief communication is to suggest that the time constants associated with magnetic field sensitivity may be a useful way to distinguish field sensitivity due to magnetite based receptors from sensitivity that may depend on direct (or downstream) biochemical processes. Bioelectromagnetics 26:234–237, 2005. © 2005 Wiley‐Liss, Inc.
Semi‐analytical computation of 3D stress singularities in linear elasticity
Authors: Mittelstedt C. , Becker W. 
Published: March 2005

AbstractThe boundary finite element method (BFEM (Finite‐Element Modelling of Unbounded Structures. Wiley: Chichester, England, 1996, The Scaled Boundary Finite Element Method. Wiley: Chichester, England, 2003)) is employed for the investigation of the order of stress singularities for several classes of three‐dimensional singular stress concentration problems, namely notch, crack and laminate free‐edge situations. In all cases, the BFEM results agree excellently with reference results. The required computational effort is considerably lower compared to e.g. standard finite element computations and thus establishes the BFEM as a powerful tool for the semi‐analytical modelling of linear elastic solids. Copyright © 2005 John Wiley & Sons, Ltd.
A robust a priori error estimate for the Fortin–Soulie finite element method
Authors: Blacker David J. 
Published: March 2005

AbstractIt is well known that conforming finite element schemes exhibit Poisson locking in the incompressible limit as the Poisson ratio ν tends to 1/2. A remedy for this is to use a non‐conforming method (Math. Comput. 1992; 59:321‐328) in which an a priori error bound is proved for the Crouzeix–Raviart scheme. In this paper we derive a new a priori estimate for the error in energy for the Fortin–Soulie finite element method using a method similar to that used in Brenner and Sung. We then illustrate the new error bound by presenting some numerical examples. Copyright © 2005 John Wiley & Sons, Ltd.
Discrimination in the Solid‐State Photodimerization of 1‐Methyl‐5,6‐diphenylpyrazin‐2‐one
Authors: Kaftory Menahem , Shteiman Vitaly , Lavy Tali , Scheffer John R. , Yang Jie , Enkelmann Volker 
Published: March 2005

Abstract1‐Methyl‐ and 1‐ethyl‐5,6‐diphenylpyrazin‐2‐one crystallize in two modifications, one of which is light‐stable and the other light‐sensitive. The light‐sensitive modification is known to undergo photodimerization in the solid state. This polymorph crystallizes in the monoclinic space group P21 with two crystallographically independent molecules in the asymmetric unit. The molecules are packed in stacks running parallel to the unique b axis. The two independent molecules are arranged alternately along the stack. In principle, there are two different pairs of molecules within a stack that can undergo photodimerization, and each should form a different enantiomer. A large crystal was irradiated and a solution of the product was separated by HPLC. The optical purity of the (+)‐enantiomer sample was estimated to be greater than 90 %. This finding indicates that only one of the two pairs undergoes photoreaction. The structure of a single crystal of the pyrazinone was elucidated by X‐ray diffractometry before and after irradiation with a laser at a wavelength of 488 nm to 19 % conversion. The results of the crystal‐structure determinations provide additional evidence that only one of the two pairs of molecules undergoes photodimeri‐zation although there are no significant differences between the distances between the reacting centers. Furthermore, the latter results suggest that weak hydrogen bonds are a dominant factor that determines which of the two pairs is dimerized upon irradiation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Antitumor Activity of the Estrane Analogue of OSW‐1
Authors: Matsuya Yuji , Masuda Seiji , Ohsawa Noriko , Adam Solange , Tschamber Théophile , Eustache Jacques , Kamoshita Keiichi , Sukenaga Yoshikazu , Nemoto Hideo 
Published: March 2005

AbstractThe estrane analogue of OSW‐1, a potent antitumor natural saponin, was efficiently synthesized from estrone in 12 steps. The cytostatic activity of the compound against several human malignant tumor cells was examined and compared to those of the natural OSW‐1 and cisplatin, the results suggesting that the modification of the steroidal component could be an effective approach in the search for new candidates of anticancer drugs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Dynamics of river–aquifer interactions along a chalk stream: the River Lambourn, UK
Authors: Grapes T. R. , Bradley C. , Petts G. E. 
Published: March 2005

AbstractThis paper describes the spatial and temporal pattern of groundwater flow accretion to the River Lambourn, a 234 km2 chalk catchment of the West Berkshire Downs, UK, which has been largely unaffected by groundwater abstraction. Variations in the discharge measured at four fixed gauges in the catchment, coupled with information on the length of flowing channel over the period 1983–2001, are used to describe regional patterns in flow accretion. Mean catchment accretion generally exceeds 0·15 m3 s−1 km−1, but there are significant differences between perennial reaches indicating how the combination of local structural controls and seasonal changes in the drainage net affect flow accretion. Data from current meter surveys were used to determine the spatial variability in flow accretion: 505 paired observations along 12 reaches between 1 and 2·95 km in length indicated a consistent spatial trend in accretion. Accretion was high in upstream and downstream channel reaches, and in middle reaches where dry valleys intersected the main valley. A flow accretion index was developed to describe the relationship of flow accretion in each of the 12 study reaches to catchment discharge. The relationship varied from a strong positive correlation with catchment discharge (two reaches), a weak positive correlation (three reaches), a strong negative correlation (two reaches), to no relationship to catchment discharge (four reaches). The results highlight the need to reconsider the usual assumption of uniform, or uniformly increasing, flow accretion in chalk catchments. Moreover, they emphasize the importance of catchment topography, and illustrate how flow accretion in individual reaches may vary between high and low groundwater levels. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of biofiltration on particle characteristics and flocculation behavior
Authors: You Hueysong , Huang Chihpin , Cheng Hsinghsuong , Pan Jill Ruhsing 
Published: March 2005

AbstractBiodegradable dissolved organic material and ammonia present problems for conventional water treatment processes and may contribute to biological instability in the treated water. One solution may be to use a biological process upstream of the regular water treatment process. Biofiltration may be cost‐effective in removing ammonia and the precursors of trihalomethanes but the characteristics of the biotreated effluent may affect to the subsequent coagulation process. A continuous flow biological filter packed with reticulated polyurethane foam markedly altered the particle size distribution and the charge density of the mixed liquor, shifting the granulometric distribution toward larger sizes. The mean and median diameter of the particles increased from 9.7 and 5.9 µm to 97.6 and 37.1 µm, respectively. The average charge density of the biofilter effluent (7.6 meq dm−3) was much lower than that of the raw water (12.7 meq dm−3). The optimum coagulant dosage for the subsequent coagulation was reduced substantially from 10 mg dm−3 to 1 mg dm−3 as Al due to the lowered charge density of the mixed liquor and the enhanced cation bridging of the extracellular polymers on the bioparticle surface. Copyright © 2005 Society of Chemical Industry
Reaction of sulfur mustard gas, soman and agent VX with nanosized anatase TiO2 and ferrihydrite
Authors: Štengl V , Maříková M , Bakardjieva S , Šubrt J , Opluštil F , Olšanská M 
Published: March 2005

AbstractHomogeneous hydrolysis of titanium oxo‐sulfate and iron(III) sulfate has been used to prepare anatase TiO2 and ferrihydrite with high specific surface area. Resulting samples were characterised by specific surface area (Brunauer–Emmett–Teller method) and porosity (Barrett–Joyner–Halenda method) measurements, X‐ray powder diffraction (XRD) and scanning electron microscopy (SEM). The samples of anatase TiO2 and ferrihydrite were evaluated for their ability to degrade chemical warfare agents (sulfur mustard gas, soman and agent VX) to non‐toxic products. The largest percentage of mustard gas converted into non‐toxic products after the completion of the reaction was 99%. Copyright © 2005 Society of Chemical Industry
Temperature Sensitive Poly[N‐isopropylacrylamide‐co‐(acryloyl β‐cyclodextrin)] for Improved Drug Release
Authors: Zhang Jian‐Tao , Huang Shi‐Wen , Liu Ji , Zhuo Ren‐Xi 
Published: March 2005

AbstractSummary: The model drugs ibuprofen (IBU) and tegafur (T‐Fu) were loaded into poly[N‐isopropylacrylamide‐co‐(acryloyl β‐cyclodextrin)] [P(NIPA‐co‐A‐CD)] and PNIPA hydrogels by immersing dried gels in IBU or T‐Fu alcohol solutions until they reached equilibrium. Drug release studies were carried out in water at 25 °C. In contrast to the release time of conventional PNIPA hydrogel, that of IBU from the β‐CD incorporated hydrogel was significantly prolonged and the drug loading was also greatly increased, which may be the result of the formation of inclusion complexes between CD and ibuprofen. However, another hydrophilic drug, tegafur, did not display these properties because it could not form a complex with the CD groups.Cumulative release of IBU from P(NIPA‐co‐A‐CD) and PNIPA hydrogels as a function of time at 25 °C.magnified imageCumulative release of IBU from P(NIPA‐co‐A‐CD) and PNIPA hydrogels as a function of time at 25 °C.