bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive oxygen species formation in the transition to hypoxia in skeletal muscle
Authors: Zuo Li , Clanton Thomas L.
Published: March 2005

Many tissues produce reactive oxygen species (ROS) during reoxygenation after hypoxia or ischemia; however, whether ROS are formed during hypoxia is controversial. We tested the hypothesis that ROS are generated in skeletal muscle during exposure to acute hypoxia before reoxygenation. Isolated rat diaphragm strips were loaded with dihydrofluorescein-DA (Hfluor-DA), a probe that is oxidized to fluorescein (Fluor) by intracellular ROS. Changes in fluorescence due to Fluor, NADH, and FAD were measured using a tissue fluorometer. The system had a detection limit of 1 μM H2O2 applied to the muscle superfusate. When the superfusion buffer was changed rapidly from 95% O2 to 0%, 5%, 21%, or 40% O2, transient elevations in Fluor were observed that were proportional to the rise in NADH fluorescence and inversely proportional to the level of O2 exposure. This signal could be inhibited completely with 40 μM ebselen, a glutathione peroxidase mimic. After brief hypoxia exposure (10 min) or exposure to brief periods of H2O2, the fluorescence signal returned to baseline. Furthermore, tissues loaded with the oxidized form of the probe (Fluor-DA) showed a similar pattern of response that could be inhibited with ebselen. These results suggest that Fluor exists in a partially reversible redox state within the tissue. When Hfluor-loaded tissues were contracted with low-frequency twitches, Fluor emission and NADH emission were significantly elevated in a way that resembled the hypoxia-induced signal. We conclude that in the transition to low intracellular Po2, a burst of intracellular ROS is formed that may have functional implications regarding skeletal muscle O2-sensing systems and responses to acute metabolic stress.
Ezrin oligomers are the membrane-bound dormant form in gastric parietal cells
Authors: Zhu Lixin , Liu Yuechueng , Forte John G.
Published: March 2005

Ezrin is a member of ezrin, radixin, moesin (ERM) protein family that links F-actin to membranes. The NH2- and COOH-terminal association domains of ERM proteins, known respectively as N-ERMAD and C-ERMAD, participate in interactions with membrane proteins and F-actin, and intramolecular and intermolecular interactions within and among ERM proteins. In gastric parietal cells, ezrin is heavily represented on the apical membrane and is associated with cell activation. Ezrin-ezrin interactions are presumably involved in functional regulation of ezrin and thus became a subject of our study. Fluorescence resonance energy transfer (FRET) was examined with cyan fluorescent protein (CFP)- and yellow fluorescent protein (YFP)-tagged ezrin incorporated into HeLa cells and primary cultures of parietal cells. Constructs included YFP at the NH2 terminus of ezrin (YFP-Ez), CFP at the COOH terminus of ezrin (Ez-CFP), and double-labeled ezrin (N-YFP-ezrin-CFP-C). FRET was probed using fluorescence microscopy and spectrofluorometry. Evidence of ezrin oligomer formation was found using FRET in cells coexpressing Ez-CFP and YFP-Ez and by performing coimmunoprecipitation of endogenous ezrin with fluorescent protein-tagged ezrin. Thus intermolecular NH2- and COOH-terminal association domain (N-C) binding in vivo is consistent with the findings of earlier in vitro studies. After the ezrin oligomers were separated from monomers, FRET was observed in both forms, indicating intramolecular and intermolecular N-C binding. When the distribution of native ezrin as oligomers vs. monomers was examined in resting and maximally stimulated parietal cells, a shift of ezrin oligomers to the monomeric form was correlated with stimulation, suggesting that ezrin oligomers are the membrane-bound dormant form in gastric parietal cells.
Pitch of Complex Tones: Rate-Place and Interspike Interval Representations in the Auditory Nerve
Authors: Cedolin Leonardo , Delgutte Bertrand
Published: March 2005

Harmonic complex tones elicit a pitch sensation at their fundamental frequency (F0), even when their spectrum contains no energy at F0, a phenomenon known as “pitch of the missing fundamental.” The strength of this pitch percept depends upon the degree to which individual harmonics are spaced sufficiently apart to be “resolved” by the mechanical frequency analysis in the cochlea. We investigated the resolvability of harmonics of missing-fundamental complex tones in the auditory nerve (AN) of anesthetized cats at low and moderate stimulus levels and compared the effectiveness of two representations of pitch over a much wider range of F0s (110–3,520 Hz) than in previous studies. We found that individual harmonics are increasingly well resolved in rate responses of AN fibers as the characteristic frequency (CF) increases. We obtained rate-based estimates of pitch dependent upon harmonic resolvability by matching harmonic templates to profiles of average discharge rate against CF. These estimates were most accurate for F0s above 400–500 Hz, where harmonics were sufficiently resolved. We also derived pitch estimates from all-order interspike-interval distributions, pooled over our entire sample of fibers. Such interval-based pitch estimates, which are dependent on phase-locking to the harmonics, were accurate for F0s below 1,300 Hz, consistent with the upper limit of the pitch of the missing fundamental in humans. The two pitch representations are complementary with respect to the F0 range over which they are effective; however, neither is entirely satisfactory in accounting for human psychophysical data.
Effect of Interocular Delay on Disparity-Selective V1 Neurons: Relationship to Stereoacuity and the Pulfrich Effect
Authors: Read Jenny C. A. , Cumming Bruce G.
Published: March 2005

The temporal properties of disparity-sensitive neurons place important temporal constraints on stereo matching. We examined these constraints by measuring the responses of disparity-selective neurons in striate cortex of awake behaving monkeys to random-dot stereograms that contained interocular delays. Disparity selectivity was gradually abolished by increasing interocular delay (when the delay exceeds the integration time, the inputs from the 2 eyes become uncorrelated). The amplitude of the disparity-selective response was a Gaussian function of interocular delay, with a mean of 16 ms (±5 ms, SD). Psychophysical measures of stereoacuity, in both monkey and human observers, showed a closely similar dependency on time, suggesting that temporal integration in V1 neurons is what determines psychophysical matching constraints over time. There was a slight but consistent asymmetry in the neuronal responses, as if the optimum stimulus is one in which the right stimulus leads by about 4 ms. Because all recordings were made in the left hemisphere, this probably reflects nasotemporal differences in conduction times; psychophysical data are compatible with this interpretation. In only a few neurons (5/72), interocular delay caused a change in the preferred disparity. Such tilted disparity/delay profiles have been invoked previously to explain depth perception in the stroboscopic version of the Pulfrich effect (and other variants). However, the great majority of the neurons did not show tilted disparity/delay profiles. This suggests that either the activity of these neurons is ignored when viewing Pulfrich stimuli, or that current theories relating neuronal properties to perception in the Pulfrich effect need to be reevaluated.
Mg2+-Malate Co-Transport, a Mechanism for Na+-Independent Mg2+Transport in Neurons of the LeechHirudo medicinalis
Authors: Günzel Dorothee , Hintz Karin , Durry Simone , Schlue Wolf-Rüdiger
Published: March 2005

Mg2+-extrusion from Mg2+-loaded neurons of the leech, Hirudo medicinalis, is mediated mainly by Na+/Mg2+antiport. However, in a number of leech neurons, Mg2+is extruded in the nominal absence of extracellular Na+, indicating the existence of an additional, Na+-independent Mg2+transport mechanism. This mechanism was investigated using electrophysiological and microfluorimetrical techniques. The rate of Na+-independent Mg2+extrusion from Mg2+-loaded leech neurons was found to be independent of extracellular Ca2+, K+, NO3−, HCO3−, SO42−, HPO42−, and of intra- and extracellular pH. Na+-independent Mg2+extrusion was not inhibited by 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS), furosemide, ouabain, vanadate, iodoacetate, 4-amino-hippurate, or α-cyano-4-hydroxycinnamate and was not influenced by changes in the membrane potential in voltage-clamp experiments. Na+-independent Mg2+extrusion was, however, inhibited by the application of 2 mM probenecid, a blocker of organic anion transporters, suggesting that Mg2+might be co-transported with organic anions. Extracellularly, of all organic anions tested (malate, citrate, lactate, α-ketoglutarate, and 4-amino-hippurate) only high, but physiological, concentrations of malate (30 mM) had a significant inhibitory effect on Na+-independent Mg2+extrusion. Intracellularly, iontophoretically injected malate, citrate, or fura-2, but not Cl−, α-ketoglutarate, glutamate, succinate, or urate, were stimulating Na+-independent Mg2+extrusion from those neurons that initially did not extrude Mg2+in Na+-free solutions. Our data indicate that Mg2+is co-transported with organic anions, preferably with malate, the predominant extracellular anion in the leech. The proposed model implies that, under experimental conditions, malate drives Mg2+extrusion, whereas under physiological conditions, malate is actively taken up, driven by Mg2+, so that malate can be metabolized.
The Theory and Practice of Corporate Governance in Russia
Authors:   Bushev
Published: March 2005

No Abstract
The Kinematic Structure of a Wasatch Mountain Winter Storm during IPEX IOP3
Authors: Cox Justin A. W. , Steenburgh W. James , Kingsmill David E. , Shafer Jason C. , Colle Brian A. , Bousquet Olivier , Smull Bradley F. , Cai Huaqing
Published: March 2005

The influence of orographic circulations on the precipitation structure of a Wasatch Mountain winter storm is examined using observations collected during the third intensive observing period (IOP3) of the Intermountain Precipitation Experiment (IPEX). The event featured the passage of a midlevel (700–550 hPa) trough followed 3 h later by a surface trough. Prior to and during the midlevel trough passage, large-scale southwesterly flow impinged on the Wasatch Mountains. Low-level confluence was observed between this southwesterly flow and along-barrier southerly flow within 20–40 km of the Wasatch Mountains. This confluence zone, which moved toward the Wasatch Mountains during and following the passage of the midlevel trough, was accompanied by low-level convergence and precipitation enhancement over the upstream lowlands. Dual-Doppler analysis revealed the presence of a shallow along-barrier jet near the base of the Wasatch Mountains that was surmounted by southwesterly cross-barrier flow at mid- and upper-mountain levels. This cross-barrier flow produced strong (1–2 m s−1) ascent as it interacted with the steep windward slopes of the Wasatch Mountains, where precipitation was roughly double that observed in the lowlands upstream. Flow deflection and splitting were also observed near the highest terrain features. A narrow region of strong subsidence, which at times exceeded 2 m s−1, was found to the lee of the Wasatch and, based on radar imagery, appeared to modulate hydrometeor spillover aloft. Processes contributing to the evolution of the near-barrier flow field, including topographic blocking, diabatic effects, and surface friction contrasts, are discussed.
Simulation of the Intraseasonal Variance of the South American Summer Monsoon
Authors: Misra Vasubandhu
Published: March 2005

This study reveals the inadequacy of the Center for Ocean–Land–Atmosphere Studies (COLA) atmospheric general circulation model (AGCM) and the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis to resolve the variance of the intraseasonal anomalies of outgoing longwave radiation (OLR) over the South American summer monsoon (SASM) domain and the equatorial eastern Pacific Ocean (EEPO) owing to their coarse horizontal resolution. However, when the NCEP–NCAR reanalysis is downscaled by roughly a factor of 2.5 using the Regional Spectral Model (RSM; control-A experiment), the simulation of the seasonal mean variance of intraseasonal anomalies of OLR improves significantly. But downscaling the results of the COLA AGCM (control-B experiment) by roughly a factor of 4 led to no further improvement.

Using the novel technique of anomaly nesting, which replaces the climatology of the COLA AGCM of the nested variables at the lateral boundaries of the RSM with the NCEP–NCAR reanalysis climatology (AN experiment), the simulation of the intraseasonal variance of OLR improves significantly over control-B runs. This improvement is shown to coincide with a distinct diurnal variation of the intraseasonal scales displayed in the AN integrations, which compare reasonably well with control-A integrations. A disappointing result of this study is that the generated variance of intraseasonal anomalies of OLR in the AN integrations arises from the internal variability of the model. However, it is concluded that the systematic errors of the COLA AGCM imposed on RSM from the lateral boundary conditions suppress the generation of intraseasonal variability.
AIDS Health Locus of Control, Self-Efficacy for Safer Sexual Practices, and Future Time Orientation as Predictors of Condom Use in African American College Students
Authors: Burns Myron J. , Dillon Frank R.
Published: March 2005

This study examined the relationship between self-reported frequency of condom use (by self or partner during the past 6 months and lifetime), locus of control, self-efficacy, and future time orientation among African American college students who were single and sexually active during the past year. Data were collected from 106 undergraduate students at a southeastern university. The sample included both men (32.1%) and women (67.9%). The mean age of the sample was 21.1 years. Locus of control did not predict condom use. Greater probability of condom use was related to higher self-efficacy and future time orientation scores. Furthermore, women with stronger future orientations exhibited more frequent current and past use of condoms in their sexual activities than males. The implications of these findings for AIDS prevention education programs are discussed.
Relationship Status, Psychological Orientation, and Sexual Risk Taking in a Heterosexual African American College Sample
Authors: Winfield Evelyn B. , Whaley Arthur L.
Published: March 2005

The present study examined relationship status, psychological orientation toward sexual risk taking, and other characteristics as potential correlates of risky sexual behavior in a sample of 223 heterosexual African American college students. Risky sexual behavior was investigated as a multinomial variable (i.e., abstinence, consistent condom use, inconsistent condom use, or noncondom use) to determine whether differentiation of levels of risky sexual behavior yielded meaningful psychological or demographic patterns. The hypotheses were (a) students who are in a long-term relationship are more likely to engage in risky sexual behavior, and (b) students who report inconsistent condom use differ from those who report noncondom use on demographic and psychological variables. The first hypothesis was partially supported. The second hypothesis was supported. The findings suggest that HIV/AIDS interventions need to take into consideration different levels of sexual risk taking with regard to condom use behavior among African American college students.
The Spoken Knowledge in Low Literacy in Diabetes Scale
Authors: Rothman Russell L. , Malone Robb , Bryant Betsy , Wolfe Catherine , Padgett Penelope , DeWalt Darren A. , Weinberger Morris , Pignone Michael
Published: March 2005

Purpose

The purpose of this study was to develop and validate a new knowledge scale for patients with type 2 diabetes and poor literacy: the Spoken Knowledge in Low Literacy patients with Diabetes (SKILLD).

Methods

The authors evaluated the 10-item SKILLD among 217 patients with type 2 diabetes and poor glycemic control at an academic general medicine clinic. Internal reliability was measured using the Kuder-Richardson coefficient. Performance on the SKILLD was compared to patient socioeconomic status, literacy level, duration of diabetes, and glycated hemoglobin (A1C).

Results

Respondents’ mean age was 55 years, and they had diabetes for an average of 8.4 years; 38% had less than a sixth-grade literacy level. The average score on the SKILLD was 49%. Less than one third of patients knew the signs of hypoglycemia or the normal fasting blood glucose range. The internal reliability of the SKILLD was good (0.72). Higher performance on the SKILLD was significantly correlated with higher income (r= 0.22), education level (r= 0.36), literacy status (r= 0.33), duration of diabetes (r= 0.30), and lower A1C (r= –0.16). When dichotomized, patients with low SKILLD scores (= 50%) had significantly higher A1C (11.2% vs 10.3%, P< .01). This difference remained significant when adjusted for covariates.

Conclusion

The SKILLD demonstrated good internal consistency and validity. It revealed significant knowledge deficits and was associated with glycemic control. The SKILLD represents a practical scale for patients with diabetes and low literacy.
Diabetes and Osteoporotic Fractures
Authors: Kemmis Karen , Stuber Diana
Published: March 2005

The purpose of this article is to present information that will assist the diabetes educator in screening patients with diabetes for risk of osteoporosis and fracture, to offer appropriate treatment options for patients, and to identify potential referrals to other providers for patients with diabetes and increased risk of fracture.
Selecting Control Interventions for Clinical Outcome Studies
Authors: Barkauskas Violet H. , Lusk Sally L. , Eakin Brenda L.
Published: March 2005

In the current research environment the design and management of control groups is becoming more complex. The selection of a control group design is dependent on study goals, presence and quality of existing interventions, urgency of the problem or issue being addressed by the intervention, and factors related to the study site. The purpose of the presentation is to identify various approaches to the design of control groups in experimental studies and to identify their strengths, limitations, and applications. A case study exemplifies the issues associated with control group selection and design.
Wound Care Using Interactive Telehealth
Authors: Moore Randall S. , Britton Bonnie , Chetney Rhonda
Published: March 2005

Effective management of wound care patients continues to be a challenge for most home health agencies. Many agencies have implemented successful programs utilizing up-to-date wound care products that decrease visits yet improve healing. Others have been fortunate enough to employ wound care specialists (e.g., certified wound ostomy and continence nurses) who can help guide their programs and provide optimum care to patients. This article discusses the options available as agencies continue their efforts to balance costs while maintaining and improving quality.
Current Legal Issues in Providing Wound Care in the Home
Authors: Newfield James S.
Published: March 2005

Personal injury claims arising from wound care in the home are a frequent source of frustration for providers. Increasing malpractice premiums, unavailable coverage, and scrutiny of wound care results have exacerbated these pressures. As patients increasingly receive wound care in the home, claims will increase. To develop effective strategies to meet these challenges, it is important to understand why exposure exists, where it exists, and where it does not exist. Personal injury claims arising from nursing wound care sound in either negligence or malpractice. These claims differ fundamentally and create different types of exposure. Appreciating these differences is important in developing strategies to effectively manage the particular risks and to understand the impact an increase in nursing expertise has on the exposure.
Ligand-induced conformational change in the T-cell receptor associated with productive immune synapses
Authors: Risueño Ruth M. , Gil Diana , Fernández Edgar , Sánchez-Madrid Francisco , Alarcón Balbino
Published: March 2005

Triggering of the T-cell receptor (TCR) can produce very different responses, depending on the nature of the major histocompatibility complex/antigen peptide (MHCp) ligand. The molecular mechanisms that permit such fine discrimination are still unknown. We show here that an epitope in the cytoplasmic tail of the TCR CD3ϵ subunit, recognized by antibody APA1/1, is only detected when the TCR is fully activated. Exposure of the APA1/1 epitope is shown to be fast and independent of tyrosine kinase activity and that it takes place even when T cells are stimulated at 0°C. These results suggest that APA1/1 detects a conformational change in the TCR. APA1/1 staining concentrates in a restricted area of the immunologic synapse. Most important, we show that full agonist, but not partial agonist, peptides induce exposure of the APA1/1 epitope, indicating a correlation between the induction of the conformational change in the TCR and full T-cell activation. Finally, the conformational change is shown to occur in T cells that are being stimulated by antigen in vivo. Therefore, these results demonstrate that the TCR undergoes a conformational change on MHCp binding in vitro and in vivo, and they establish a molecular correlate for productive TCR engagement. (Blood. 2005;106:601-608)
Diabetes-prone NOD mice show an expanded subpopulation of mature circulating monocytes, which preferentially develop into macrophage-like cells in vitro
Authors: Nikolic Tatjana , Bouma Gerben , Drexhage Hemmo A , Leenen Pieter J M
Published: March 2005

In the nonobese diabetic (NOD) mouse, a model of autoimmune diabetes, dendritic cells (DC), and macrophages (Mφ) is important for the initiation and progression of autoimmunity and the final destruction of β-cells. Previous studies suggested that an aberrant development of DC and Mφ is related to their pathogenic function. To study this in vivo, we investigated NOD mouse monocytes, the direct precursors of DC, and Mφ. The recently described discrimination between immature (Ly-6Chigh) and mature (Ly-6Clow) monocytes enabled us to investigate the apportioning between blood monocyte populations in the NOD mouse, which had an abnormally high number of mature monocytes in circulation, and this phenomenon appeared to be intrinsic to the NOD background, as nonobese resistant (NOR) and NOD-H2b mice also showed this altered balance. After depletion by apoptosis-inducing liposomes, the reappearance and transition of immature-to-mature monocytes had similar kinetics as control mice but led again to the presence of a larger, mature monocyte compartment in the blood. In addition, although monocytes from C57BL mice down-regulated their capability to adhere to fibronectin and intercellular adhesion molecule-1 upon maturation, the mature NOD monocytes retained their high adhesion capacity, characteristic of immature cells. Furthermore, both monocyte subpopulations of NOD mice showed enhanced differentiation into Mφ-like F4/80high cells in vitro. In conclusion, mice with the NOD background have raised numbers of mature monocytes in the circulation and a proinflammatory, Mφ-directed monocyte development.
Reform of Japan’s official development assistance: a complete overhaul or merely a fresh coat of paint?
Authors: Scheyvens Henry
Published: March 2005

Japan’s official development assistance (ODA) programme, the world’s second largest, is best known for its funding of large-scale infrastructure projects. However, the aid programme has been undergoing a process of reform and more progressive aid projects are emerging. The paper concludes that although an increase in the number of such projects can be expected, large-scale infrastructure projects will remain the centrepiece of Japan’s aid programme.
The implications of the demographic transition for women, girls and gender equality: a review of developing country evidence
Authors: McNay Kirsty
Published: March 2005

The demographic transition has become a dramatic global phenomenon, in which most developing countries are now participating. While much has been written about the impact of women’s roles and status on the transition, significantly less has been said about the relationship in the other direction, i.e., the implications of declining mortality and fertility for women’s lives. This paper presents a review of the evidence on these consequences in developing countries. It argues that although the demographic transition is generally a positive process for women, there is not always a straightforward link to improvements in female status and gender equality.
Six1 and Six4 homeoproteins are required for Pax3 and Mrf expression during myogenesis in the mouse embryo
Authors: Grifone Raphaelle , Demignon Josiane , Houbron Christophe , Souil Evelyne , Niro Claire , Seller Mary J. , Hamard Ghislaine , Maire Pascal
Published: March 2005

In mammals, Six5, Six4 and Six1 genes are co-expressed during mouse myogenesis. Six4 and Six5 single knockout (KO)mice have no developmental defects, while Six1 KO mice die at birth and show multiple organ developmental defects. We have generated Six1Six4 double KO mice and show an aggravation of the phenotype previously reported for the single Six1 KO. Six1Six4 double KO mice are characterized by severe craniofacial and rib defects, and general muscle hypoplasia. At the limb bud level, Six1 and Six4homeogenes control early steps of myogenic cell delamination and migration from the somite through the control of Pax3 gene expression. Impaired in their migratory pathway, cells of the somitic ventrolateral dermomyotome are rerouted, lose their identity and die by apoptosis. At the interlimb level, epaxial Met expression is abolished, while it is preserved in Pax3-deficient embryos. Within the myotome, absence of Six1and Six4 impairs the expression of the myogenic regulatory factors myogenin and Myod1, and Mrf4 expression becomes undetectable. Myf5 expression is correctly initiated but becomes restricted to the caudal region of each somite. Early syndetomal expression of scleraxis is reduced in the Six1Six4 embryo, while the myotomal expression of Fgfr4 and Fgf8 but not Fgf4 and Fgf6 is maintained. These results highlight the different roles played by Six proteins during skeletal myogenesis.
Analysis of xbx genes in C. elegans
Authors: Efimenko Evgeni , Bubb Kerry , Mak Ho Yi , Holzman Ted , Leroux Michel R. , Ruvkun Gary , Thomas James H. , Swoboda Peter
Published: March 2005

Cilia and flagella are widespread eukaryotic subcellular components that are conserved from green algae to mammals. In different organisms they function in cell motility, movement of extracellular fluids and sensory reception. While the function and structural description of cilia and flagella are well established, there are many questions that remain unanswered. In particular, very little is known about the developmental mechanisms by which cilia are generated and shaped and how their components are assembled into functional machineries. To find genes involved in cilia development we used as a search tool a promoter motif, the X-box, which participates in the regulation of certain ciliary genes in the nematode Caenorhabditis elegans.

By using a genome search approach for X-box promoter motif-containing genes(xbx genes) we identified a list of about 750 xbx genes(candidates). This list comprises some already known ciliary genes as well as new genes, many of which we hypothesize to be important for cilium structure and function. We derived a C. elegans X-box consensus sequence by in vivo expression analysis. We found that xbx gene expression patterns were dependent on particular X-box nucleotide compositions and the distance from the respective gene start. We propose a model where DAF-19, the RFX-type transcription factor binding to the X-box, is responsible for the development of a ciliary module in C. elegans, which includes genes for cilium structure, transport machinery, receptors and other factors.
Effect of dietary fatty acid composition on depot fat and exercise performance in a migrating songbird, the red-eyed vireo
Authors: Pierce Barbara J. , McWilliams Scott R. , O'Connor Timothy P. , Place Allen R. , Guglielmo Christopher G.
Published: March 2005

Most migrating birds accumulate lipid stores as their primary source of energy for fueling long distance flights. Lipid stores of birds during migration are composed of mostly unsaturated fatty acids; whether such a fatty acid composition enhances exercise performance of birds is unknown. We tested this hypothesis by measuring metabolic rate at rest and during intense exercise in two groups of red-eyed vireos, a long-distance migratory passerine, fed either a diet containing 82% unsaturated fat (82%U), or one containing 58% unsaturated fat (58%U). Vireos fed the 82%U diet had fat stores containing (77%) unsaturated fatty acids, whereas vireos fed the 58% U diet had fat stores containing less (66%) unsaturated fatty acids. Blood metabolites measured prior to and immediately following exercise confirmed that vireos were metabolizing endogenous fat during intense exercise. Mass-specific resting metabolic rate (RMR) was similar for vireos fed the 58%U diet (2.75±0.32 ml O2 g–1h–1) and for vireos fed the 82%U diet (2.30±0.30 ml O2 g–1 h–1). However,mass-specific peak metabolic rate (MRpeak) was 25% higher in vireos fed the 58%U diet (28.55±1.47 ml O2 g–1h–1) than in vireos fed the 82%U diet (21.50±1.76 ml O2 g–1 h–1). Such whole-animal energetic effects of fatty acid composition of birds suggest that the energetic cost of migration in birds may be affected by the fatty acid composition of the diet.
Testing the hindlimb-strength hypothesis: non-aerial locomotion by Chiroptera is not constrained by the dimensions of the femur or tibia
Authors: Riskin Daniel K. , Bertram John E. A. , Hermanson John W.
Published: March 2005

In the evolution of flight bats appear to have suffered a trade-off; they have become poor crawlers relative to terrestrial mammals. Capable walking does occur in a few disparate taxa, including the vampire bats, but the vast majority of bats are able only to shuffle awkwardly along the ground, and the morphological bases of differences in crawling ability are not currently understood. One widely cited hypothesis suggests that the femora of most bats are too weak to withstand the compressive forces that occur during terrestrial locomotion, and that the vampire bats can walk because they possess more robust hindlimb skeletons. We tested a prediction of the hindlimb-strength hypothesis: that during locomotion, the forces produced by the hindlimbs of vampire bats should be larger than those produced by the legs of poorly crawling bats. Using force plates we compared the hindlimb forces produced by two species of vampire bats that walk well, Desmodus rotundus(N=8) and Diaemus youngi (N=2), to the hindlimb forces produced during over-ground shuffling by a similarly sized bat that is a poor walker (Pteronotus parnellii; N=6). Peak hindlimb forces produced by P. parnellii were larger (ANOVA; P<0.05; N=65) and more variable (93.5±36.6% body weight, mean ± s.d.) than those of D. rotundus(69.3±8.1%) or D. youngi (75.0±6.2%). Interestingly,the vertical components of peak force were equivalent among species(P>0.6), indicating similar roles for support of body weight by the hindlimbs in the three species.

We also used a simple engineering model of bending stress to evaluate the support capabilities of the hindlimb skeleton from the dimensions of 113 museum specimens in 50 species. We found that the hindlimb bones of vampires are not built to withstand larger forces than those of species that crawl poorly. Our results show that the legs of poorly crawling bats should be able to withstand the forces produced during coordinated crawling of the type used by the agile vampires, and this indicates that some mechanism other than hindlimb bone thickness, such as myology of the pectoral girdle, limits the ability of most bats to crawl.
A novel diuretic hormone receptor inDrosophila: evidence for conservation of CGRP signaling
Authors: Johnson Erik C. , Shafer Orie T. , Trigg Jennifer S. , Park Jae , Schooley David A. , Dow Julian A. , Taghert Paul H.
Published: March 2005

The Drosophila orphan G protein-coupled receptor encoded by CG17415 is related to members of the calcitonin receptor-like receptor (CLR) family. In mammals, signaling from CLR receptors depend on accessory proteins, namely the receptor activity modifying proteins (RAMPs)and receptor component protein (RCP). We tested the possibility that this Drosophila CLR might also require accessory proteins for proper function and we report that co-expression of the mammalian or Drosophila RCP or mammalian RAMPs permitted neuropeptide diuretic hormone 31 (DH31) signaling from the CG17415 receptor. RAMP subtype expression did not alter the pharmacological profile of CG17415 activation. CG17415 antibodies revealed expression within the principal cells of Malpighian tubules, further implicating DH31 as a ligand for this receptor. Immunostaining in the brain revealed an unexpected convergence of two distinct DH signaling pathways. In both the larval and adult brain, most DH31 receptor-expressing neurons produce the neuropeptide corazonin, and also express the CRFR-related receptor CG8422, which is a receptor for the neuropeptide diuretic hormone 44 (DH44). There is extensive convergence of CRF and CGRP signaling within vertebrates and we report a striking parallel in Drosophila involving DH44 (CRF) and DH31 (CGRP). Therefore, it appears that both the molecular details as well as the functional organization of CGRP signaling have been conserved.
Dynamical (harmonic) interface stress field in the half-plane covered by the prestretched layer under a strip load
Authors: Akbarov S D , Guler C
Published: March 2005

Within the framework of the piecewise homogeneous body model, by employing the three-dimensional linearized theory of elastic waves in initially stressed bodies the dynamical problem of the stress distribution in a half-plane covered with a prestretched layer is investigated. It is assumed that the free face plane of the covered layer is subjected to a uniformly distributed harmonic load acting on a strip extending to infinity in the x3 direction, which is perpendicular to the x1-x2 plane and is of width 2a in the x1 direction. The plane-strain state in the x1-x2 plane is analysed.

The corresponding boundary-value problems are investigated by employing the exponential Fourier integral transformation. The numerical results regarding the interface normal stress distribution are presented. The influences of the problem parameters and pre-stretching of the covered layer on this distribution are analysed. Practical engineering application fields of the results are suggested.
Computational studies of the laminar burning velocity of a producer gas and air mixture under typical engine conditions
Authors: Sridhar G , Paul P J , Mukunda H S
Published: March 2005

This paper discusses computational results concerning the laminar burning velocity of a biomass-derived producer gas and air mixture at pressures and temperatures typical of the unburned mixture in a reciprocating engine. The computations are based on solving conservation equations describing laminar one-dimensional, multicomponent, chemically reacting, and ideal gas mixtures that have been formulated by earlier researchers. Based on a number of calculations at varying initial pressures and temperatures, and equivalence ratios, an expression for estimating the laminar burning velocity with the recycled gas mass fraction has been obtained. Also, the effect of varying amounts of recycled gas on the burning velocity has been determined. These data on laminar burning velocities will be useful in predicting the burnrate in a spark ignition (SI) engine fuelled with a producer gas and air mixture.
Studies on mechanical and thermal properties of ternary blends of polyethylenes. I
Authors: Srivastava Deepak
Published: March 2005

Six film samples of varying compositions of linear low‐density polyethylene (LLDPE), 10–35 wt %, and high‐density polyethylene (HDPE), 40–65 wt %, having a fixed percentage of low‐density polyethylene (LDPE) at 25 wt % were extruded by melt blending in a single‐screw extruder (L/D ratio = 20 : 1) of uniform thickness of 2 mil. The tensile strength, elongation at break, and impact strength were found to increase up to 60 wt % HDPE addition, starting from 40 wt % HDPE, in the blends and then decreased. The blend sample B‐500 was found to be more thermally stable than its counterparts. The appearance of a single peak beyond 45 wt % HDPE content in the blend in dynamic DSC scans showed the formation of miscible blend systems and this was further confirmed by scanning electron microscopic analysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1691–1698, 2005
Effect of nanosized calcium carbonate on the mechanical properties of latex films
Authors: Manroshan S. , Baharin A.
Published: March 2005

An acrylic dispersed nanosized calcium carbonate filler was added to a prevulcanized latex compound in different amounts. The effect of filler content on the curing time, modulus, tensile strength, elongation at break (Eb) before and after ageing, and the morphology of the films was investigated. Results showed that the curing time decreased with filler loading because of the increased interaction between the filler and rubber matrix, as reflected by the decrease in the apparent swelling index. Modulus at 100% elongation and modulus at 300% elongation increased with filler loading. Tensile strength and Eb increased up to 10 phr of filler loading and then decreased again. Aged films showed improved mechanical properties compared to those of unaged films. Micrographs showed that agglomeration occurred as the filler content was increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1550–1556, 2005
Synthesis and characterization of poly(o‐toluidine) doped with organic sulfonic acid by solid‐state polymerization
Authors: Abdiryim Tursun , Xiao‐Gang Zhang , Jamal Ruxangul
Published: March 2005

Poly (o‐toluidine) (POT) salts doped with organic sulfonic acids (β‐naphthalene sulfonic acid, camphor sulfonic acid, and p‐toluene sulfonic acid) were directly synthesized by using a new solid‐state polymerization method. The FTIR spectra, ultraviolet visibility (UV–vis) absorption spectra, and X‐ray diffraction patterns were used to characterize the molecular structures of the POT salts. Voltammetric study was done to investigate the electrochemical behaviors of all these POT salts. The FTIR and UV–vis absorption spectra revealed that the POT salts were composed of mixed oxidation state phases. All POT salts contained the conducting emeraldine salt (half‐oxidized and protonated form) phase; the pernigraniline (fully oxidized form) phase is predominant in POT doped with β‐naphthalene sulfonic acid, and POT doped with p‐toluene sulfonic acid had the highest doping level. The X‐ray diffraction patterns showed that the obtained POT doped with organic sulfonic acids were lower at crystallinity. The conductivity of the POT salts were found to be of the order 10−3‐10−4 S/cm. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1630–1634, 2005
Effect of long‐chain branches of polypropylene on rheological properties and foam‐extrusion performances
Authors: Nam G. J. , Yoo J. H. , Lee J. W.
Published: March 2005

The effect of modifying polypropylene by the addition of long‐chain branches on the rheological properties and performance of foam extrusion was studied. Three polypropylenes, two long‐chain‐branched polypropylenes and a linear polypropylene, were compared in this study. The modification was performed with a reactive‐extrusion process with the addition of a multifunctional monomer and peroxide. The rheological properties were measured with a parallel‐plate and elongational rheometer to characterize the branching degree. The change from a linear structure to a long‐chain‐branched nonlinear structure increased the melt strength and elasticity of polypropylene. Also, there was a significant improvement in the melt tension and sag resistance for branched polypropylenes. Foaming extrusion was performed, and the effect of the process variables on the foam density was analyzed with Taguchi's experimental design method. For this study, an L18(2135) orthogonal array was used on six parameters at two or three levels of variation. The considered parameters were the polypropylene type, the blowing agent type, the blowing agent content, the die temperature, the screw speed (rpm), and the capillary die length/diameter ratio. As a result, the most significant factor that influenced the foam density was the degree of long‐chain branching of polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1793–1800, 2005
Investigation of acetyl ferrocene migration from hydroxyl‐terminated polybutadiene based elastomers by means of ultraviolet–visible and atomic absorption spectroscopic techniques
Authors: Ünver Alper , Dilsiz Nursel , Volkan Mürvet , Akovalı Güneri
Published: March 2005

Migration and leakage of some mobile components in rocket propellant produces an inhomogeneous composition region at which migration takes place, which can lead to premature detonation, changes in ballistic characteristics, and so on. It is, therefore, important to be able to predict the behavior of low‐molecular‐weight mobile additives and to control the leakage of them from the propellant. At this point, our chief interest was to study the magnitude of the migration and to understand the factors that influence the migration process. In this study, the migration of a ferrocene‐based burning‐rate catalyst [acetyl ferrocene (AcF)] a from hydroxyl‐terminated polybutadiene (HTPB) based elastomer in the presence of a plasticizer (dioctyl adipate) was examined in accelerated aging conditions at 60°C for various time intervals. We also tried to minimize the migration of AcF from the loaded to the unloaded part by using an extra barrier layer consisting of polyfunctional aziridine (AST D45+) in addition to the HTPB–toluene diisocyanate composition. The migration enhanced with aging of the AcF and the barrier effects of the layer with intensified crosslink density to this migration were studied extensively. The migration was monitored by both ultraviolet–visible and atomic absorption spectroscopy (AAS) methods. A comparison of the data obtained from both of these methods was also done. The two techniques were found to be in agreement, and the Fe determinations from both methods were highly correlated, suggesting that the data were reliable, although the AAS data were found to be symmetrically somewhat higher. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1654–1661, 2005
Competing effect between filled glass bead and induced β crystal on the tensile properties of polypropylene/glass bead blends
Authors: Yuan Qiang , Jiang Wei , An Lijia , Christiansen Jesper Declaville , Li R. K. Y.
Published: March 2005

The blends of the polypropylene (PP‐1) with various glass bead contents were prepared via melt blending. Differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD) results indicated that the β crystal existed in PP‐1 and increased with increasing glass bead content up to 6 wt %. It was generally known that the stiffness of a polymer increased with introducing rigid particles, and the stiffness of the β crystal was less than that of the α crystal. This competing effect thus leads to the tensile modulus of PP‐1/glass bead blend decreasing with increasing glass bead content up to 6 wt %; thereafter, it increased with increasing glass bead content. For the purpose of comparison, the polypropylene (PP‐2) without the β crystal was employed to blend with glass bead. The tensile tests showed that the modulus of the PP‐2/glass bead blend increased continuously with increasing glass bead content. This result further supported that the tensile modulus behavior of PP‐1/glass bead blends resulted from the competing between the filled glass bead and the induced β crystal. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1729–1733, 2005
Thermosensitive poly(N‐isopropylacrylamide) hydrogel for refolding of recombinant bovine prethrombin‐2 from E. coli inclusion bodies
Authors: Cui Zhi‐Fang , Guan Yi‐Xin , Chen Jian‐Liang , Yao Shan‐Jing
Published: March 2005

The poly(N‐isopropylacrylamide) (PNIPA) hydrogel, which is a kind of temperature‐sensitive polymer, was synthesized by inverse suspension polymerization. The microscopy and scan electron microscopy (SEM) of PNIPA hydrogel were studied. The microscope photograph showed that the particles were in the range of 0.2–0.5mm in diameter, with numerous conjoint pores about 1–2μm spreading all over the surface of the beads. The swelling properties of PNIPA gel beads indicated that the lower critical solution temperature (LCST) of the gel was 33°C. The PNIPA prepared was applied to the renaturation of bovine prethrombin‐2 (pThr‐2) from inclusion bodies produced in E. coli. It was observed that PNIPA was quite efficient in assisting protein renaturation at high protein concentration. When mixing with 105mg/mL PNIPA hydrogel during the refolding, the total activity of the thrombin was about 6222U/mL, compared with only 2800U/mL by simple dilution refolding. The kinetics of pThr‐2 refolding with the absence or the presence of PNIPA was also studied respectively. The time required for the refolding with PNIPA gel was a little bit longer than that by the dilution method owing to the diffusion resistance of the protein into the network of the gel and the hydrophobic interaction between the protein and the polymer. The mechanism of the enhancement for the PNIPA gel to the refolding was further discussed. The porosity of the PNIPA hydrogel allows penetration of the unfolded protein into the inside of the polymer with a hydrophobic side chain, which can facilitate the formation of intermediate via hydrophobic interaction with the unfolded protein and the folding intermediate that are liable to re‐aggregation. About 1.2mg of purified active thrombin could be recovered from 1 L of cells, which greatly facilitated the scale‐up to the quantities of protein necessary for further functional and structural studies. A novel protein renaturation method mediated by PNIPA hydrogel beads, which highly increases the refolding efficiency with easy handling, recycling, and low cost, was proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1734–1740, 2005