bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of global cotton markets on rural poverty in Benin
Authors: Minot Nicholas , Daniels Lisa
Published: November 2005

World cotton prices fell by about 40% over 2001–2002, focusing attention on the effect of subsidies for cotton growers in depressing world prices. This paper combines farm survey data from Benin with assumptions about the decline in farm‐level prices to estimate the direct and indirect effects of cotton price reductions on rural income and poverty in Benin. The results indicate that there is a strong link between cotton prices and rural welfare in Benin. A 40% reduction in farm‐level prices of cotton results in an increase in rural poverty of 8% points in the short run and 6–7% points in the long run. Under the assumptions of the partial input‐output model, we estimate the multiplier to be in the range of 2.96, meaning that 1 US$ of reduced income by cotton growers results in a contraction of 2.96 US$ in overall income. Finally, econometric analysis of the determinants of the demand for hired agricultural labor suggests that falling cotton prices will not greatly reduce labor demand since the labor intensity of cotton is similar to that of competing crops in Benin. Overall, the study demonstrates the impact of changes in world cotton prices on rural poverty in Benin, thus highlighting the likely negative effects of cotton subsidies in the United States and elsewhere on Benin farmers.
Targeting of Proteins of the Striatin Family to Dendritic Spines: Role of the Coiled‐Coil Domain
Authors: Gaillard Stéphane , Bailly Yannick , Benoist Marion , Rakitina Tatiana , Kessler Jean‐Pierre , Fronzaroli‐Molinières Laure , Dargent Bénédicte , Castets Francis
Published: November 2005

Striatin, SG2NA and zinedin, the three mammalian members of the striatin family are multimodular WD‐repeat, calmodulin and calveolin‐binding proteins. These scaffolding proteins, involved in both signaling and trafficking, are highly expressed in neurons. Using ultrastructural immunolabeling, we showed that, in Purkinje cells and hippocampal neurons, SG2NA is confined to the somatodendritic compartment with the highest density in dendritic spines. In cultured hippocampal neurons, SG2NA is also highly concentrated in dendritic spines. By expressing truncated forms of HA‐tagged SG2NAβ, we demonstrated that the coiled‐coil domain plays an essential role in the targeting of SG2NA within spines. Furthermore, co‐immunoprecipitation experiments indicate that this coiled‐coil domain is also crucial for the homo‐ and hetero‐oligomerization of these proteins. Thus, oligomerization of the striatin family proteins is probably an obligatory step for their routing to the dendritic spines, and hetero‐oligomerization explains why all these proteins are often co‐expressed in the neurons of the rat brain and spinal cord.
Synergistic effect of cellulase and hemicellulase on nutrient utilization and performance in broilers fed a corn–soybean meal diet
Authors: TAHIR Muhammad , SALEH Fuad , OHTSUKA Akira , HAYASHI Kunioki
Published: November 2005

In the present study, the synergistic effect of dietary cellulase and hemicellulase on the nutrient utilization, performance and digesta (content of jejunum) viscosity in broilers fed a corn–soybean meal diet were studied. The treatment groups included a control, cellulase (0.33 U/g feed), hemicellulase (2 U/g feed) and mixed enzyme (cellulase (0.33 U/g feed) + hemicellulase (2 U/g feed)) group. The enzymes were mixed with the basal diet (21.1% crude protein, 3000 kcal/kg metabolizable energy) and fed to male broiler chickens (Cobb strain) for 12 days from 15 days of age. Feed and water were offered ad libitum. Chicks were raised under 25°C in wire‐bottomed cages during the entire experimental period. We found that broilers given enzymes grew faster, and that the mixed enzyme was most effective. Feed intake remained the same for all of the treatment groups. Carcass weight was increased by mixed enzyme significantly, but not by cellulase and hemicellulase. The enzymes, but not mixed enzyme, decreased abdominal fat and were significant in the case of cellulase. Enzymes did not affect muscle weight and nitrogen‐retention, but metabolizable energy content of the diet was improved by the mixed enzyme. Ash‐retention was increased by hemicellulase and mixed enzyme. Digesta viscosity was significantly decreased by cellulase, but not by hemicellulase and the mixed enzyme. The results indicate that the combination of cellulase and hemicellulase has a synergistic effect on the performance of broilers fed a corn–soybean meal diet.
Fecal ammonia, urea, volatile fatty acid and lactate levels in dairy cows and their pathophysiological significance during diarrhea
Authors: SATO Hiroshi , NAKAJIMA Junko
Published: November 2005

Normal fecal samples were taken from lactating cows fed either a total mixed ration (TMR; n = 30) or pasture‐based diet (20) and from dry cows fed mainly on hay (15). Diarrheic fecal samples (n = 51) were collected from 21 sick dairy cows. Fecal analyses of ammonia, urea, lactate and volatile fatty acid (VFA) levels were used to evaluate colonic fermentation. Most normal feces had reasonably neutral pH, however, alkaline feces were observed in diarrheic cows. Although fecal lactate is higher in cows on grazing pasture, lactate levels were generally lower in the cows in the present study. Fecal VFA levels were higher in lactating cows than in dry cows. Elevated fecal urea was observed in diarrheic cows, however, many fecal samples in normal and diarrheic cows contained no urea. Fecal VFA levels in diarrheic cows were lower than in normal lactating cows, but were approximately equivalent to those in dry cows. Grazing or dry cows showed higher acetate and lower n‐butyrate proportions compared with TMR‐fed or diarrheic cows. Higher proportions of branched chain VFAs were observed in diarrheic cows, and the lowest level was observed in grazing cows. The present results indicate that intracolonic nitrogen equilibrium and proteolytic fermentation are altered by diarrheic status.
On the stabilizing virtues of imperfect competition
Authors: Seegmuller Thomas
Published: November 2005

We analyze the stabilizing role of imperfect competition on fluctuations as a result of indeterminacy and endogenous cycles. In this paper, imperfect competition is a source of monopoly profits, because of producer market power. Considering an overlapping generations model with capital accumulation and elastic labor supply, we show that under imperfect competition, the emergence of endogenous fluctuations requires a weaker substitution between production factors than under perfect competition. In this sense, imperfect competition stabilizes fluctuations. However, we find an opposite conclusion concerning the elasticity of labor supply. Indeed, endogenous fluctuations are compatible with a less elastic labor supply under imperfect competition.
Effects of hot compress treatment with a hot water bottle on physiological parameters and subjective sensations in healthy women
Authors: HASEBE Yoshiko
Published: November 2005

Aim: The purpose of this study was to obtain data on young women during the afternoon, which would be comparable with the results of previous research performed in the morning, in order to examine the effects of hot compresses in the form of hot water bottles on physiological responses and subjective evaluation, and to investigate interactions between the measured values and physical factors, including menstrual variations.

Methods: A crossover design using hot water bottles at 80, 55, and 30°C was used, and 11 healthy female students participated in the study. The hot water bottles at 30°C were used as controls, because 30°C is approximately the internal temperature of a bed. Each hot water bottle was applied to the plantar feet.

Results: The major findings of our study were that: (i) water temperature in the hot water bottle has significant effects on the subjective thermal sensation, the deep plantar temperature, and the in‐bed humidity; (ii) the 80°C bottle was superior to the 55°C bottle with regard to the subjective sensations of the subject; and (iii) thermal sensation may be correlated with the deep plantar temperature, the in‐bed temperature and the in‐bed humidity.

Conclusions: The present study indicates that it is very likely that thermal sensation is affected by the temperature of water in the hot water bottle. When using a hot water bottle to warm up young women in the afternoon, augmentation of cutaneous blood flow in the toes does not seem to be the best index of thermal sensation.
Innovations in United States genetics nursing: Practice and research
Authors: LEA Dale H. , COOKSEY Judith A. , FLANAGAN Patricia A. , WILLIAMS Janet K. , FORTE Gaetano
Published: November 2005

Aim:  Clinical and research applications from human genome discoveries are growing and creating both opportunities and challenges to the integration of genetic concepts into practice and research. Nurses have a long history of caring for individuals, families, and groups with genetic conditions. In the past two decades, a small group of nurses in the USA have used a variety of strategies to further develop the field of genetics nursing. In this paper we identify innovative approaches to identifying genetics‐related nursing roles and opportunities, as well as successful collaborative efforts beyond nursing to address the emerging health and societal challenges related to human genetics discoveries.

Methods:  The information presented here comes from a variety of sources where the authors or genetics nurses directly participated, including: (i) a systematic literature review of genetics nursing; (ii) a comprehensive research study of models of delivering clinical genetics services and the roles of health professionals; and (iii) participation in numerous national research, planning, programmatic, and advisory groups involved with clinical genetics‐related health services, research, education, and public policy.

Results:  Genetics nurses in the US have developed innovative responses to genetics‐related challenges within and beyond the profession of nursing. These include: (i) establishing an organization for nurses in genetics and gaining formal recognition of genetics as a specialty of nursing; (ii) defining the scope of genetics nursing practice and developing a new genetics nursing credential; (iii) establishing a multiprofessional genetics education coalition and defining genetic competency for health‐care practice; (iv) creating new clinical practice roles for nurses that integrate emerging genetics concepts and skills into diverse clinical practice areas; (v) expanding nursing involvement in genetics‐related research; and (vi) participation in high‐level genetics advisory groups.

Conclusions:  The US experience shows that nurses have made substantial progress in expanding their involvement in genetic services through visionary leadership, innovative approaches to challenges, establishing support with nurse colleagues, and engaging in multiprofessional efforts. The most important first step is developing a supportive environment for nurse advancement. In the US, the genetics nurses’ organization known as the International Society of Nurses in Genetics (ISONG) has provided this base.
USE OF FOURIER TRANSFORM MECHANICAL SPECTROSCOPY TO STUDY THE MELTING BEHAVIOR OF CHEESE
Authors: UDAYARAJAN C.T. , LUCEY J.A. , HORNE D.S.
Published: November 2005

Fourier Transform Mechanical Spectroscopy (FTMS), which employs a complex sinusoidal waveform, was investigated for its applicability in measuring the rheological properties in the cheese system. The complex wave used in FTMS is a superposition of several sine waves whose frequencies are harmonics of a base frequency. FTMS was used to investigate the rheological properties of a 10‐month‐old Cheddar cheese while the sample was heated from 10 to 90C or cooled from 90 to 10C at the rate of 1C/min or 0.5C/min. The component frequencies of the complex waveform were 0.08, 0.4, 0.8 and 4 Hz. The widely used small amplitude oscillatory shear (SAOS) measurements, which employ only discrete frequencies, were also conducted on separate cheese samples to test the robustness of FTMS results. During heating, the values of the storage modulus (G′) and loss modulus (G″) decreased by at least four orders of magnitude. In the temperature region from 44 to 55C, there was a shoulder in the G′ and G″ profiles, which was more pronounced at high frequencies; and in the high‐temperature region from 70 to 90C, the dynamic moduli values either reached a plateau or slightly increased. The frequency dependence of the dynamic moduli increased after 40C. The temperature and values of dynamic moduli at the crossover of G′ and G″ were highly dependent on frequency. Clear maxima were observed in loss tangent (LT) profiles and the temperature of maxima and their values were highly dependent on frequency. Results were similar for both rates of heating, but the heating and cooling curves for G′, G″ and LT showed hysteresis. The results from FTMS agreed well with the SAOS measurements for all the frequencies tested and indicated that the FTMS technique is a useful method to probe the molecular behavior of cheese systems while undergoing heating or cooling.
CONSISTENCY OF DISPERSED FOOD SYSTEMS AND ITS EVALUATION BY SQUEEZING FLOW VISCOMETRY
Authors: CORRADINI MARIA G. , PELEG MICHA
Published: November 2005

In testing semiliquid foods, conventional viscometers have two major problems: slip and disruption of the specimen's microstructure upon its insertion into the narrow gap of the sensor. These two problems are almost completely eliminated when lubricated squeezing flow viscometry is used; slip becomes a prerequisite for a proper test and, because of the large initial distance between the plates, the specimen can be tested practically intact. The penalty is that with the instrumentation commonly available in food research and quality assurance laboratories, the method can only be used at fairly small rates. In squeezing flow viscometry, the overall consistency of the tested material can be expressed in terms of the apparent stress at a given specimen height and its “degree of solidity” by the residual apparent stress at a given specimen height, measured after more than a minute at relaxation. The method is sensitive enough to determine differences between semiliquid foods, to record changes in their rheological properties as a result of shearing and to monitor their ability to recover their consistency when left to rest. The method also allows to follow the structural development of foams during their formation and collapse, because of drainage, when left undisturbed.
Protein gel electrophoresis in the undergraduate physics laboratory
Authors: Miles Danny G. , Bushman David W. , Chen Zhong-Ying
Published: November 2005

We describe an undergraduate laboratory experiment in protein gel electrophoresis that uses readily available apparatus and materials. The separation of a mixture of stained proteins by gel electrophoresis was videotaped. Position–time data for the proteins generated from analysis of digitized videotape images allowed for calculation of protein terminal velocities. The dependence of protein terminal velocity on molar mass was determined and found to agree with predictions made by current theory. We also introduce a model that draws on simple physical concepts to help students place the experimental results in context.
Construction and calibration of a low cost Fabry-Perot interferometer for spectroscopy experiments
Authors: Fletcher Colin D. , Orzel Chad
Published: November 2005

We describe the construction and calibration of a low cost confocal scanning Fabry-Perot interferometer with a free spectral range of 382.3±1.1MHz, which is suitable for use as a frequency reference in laser locking and for spectroscopy experiments. The calibration of the free spectral range is performed using the longitudinal modes of a commercial helium–neon laser.
Fun with stacking blocks
Authors: Hall John F.
Published: November 2005

How can a given number of rigid, rectangular blocks be stacked in a planar arrangement to produce the maximum overhang over a support edge? To answer this question, three cases of increasing complexity are considered: single-wide stacks, multiwide stacks that do not rely on friction, and multiwide stacks that do rely on friction. The solution to the first case has existed for more than 150 years; the answer to the second case is attempted in this paper; and the considerable complexity of the third is demonstrated. Many mathematical aspects of block stacking are discussed, and a new challenge is posed. The analysis uses the principles of static equilibrium and stability and free body diagrams, key concepts in classical mechanics.
Fluctuation correlation spectroscopy for the advanced physics laboratory
Authors: Rieger Robert , Röcker Carlheinz , Nienhaus G. Ulrich
Published: November 2005

A fluorescence correlation spectrometer is developed that is suitable for use in advanced laboratory courses. The instrument is simple to build and understand and can be constructed at a small fraction of the cost of a commercial or research-grade instrument. We demonstrate its surprisingly high performance with a simple biophysics application, the study of the binding of two complementary DNA strands. The instrument will be useful in areas of physics where precise measurements of the dynamics of fluorescent (or fluorescently labeled) molecules or nanoparticles in solution are of interest.
The mystique of physics: Relumine the Enlightenment
Authors: Rigden John S.
Published: November 2005

There is a mystique to physics because people are inherently receptive to the qualities that make physics special. It is this receptivity and the resulting mystique that makes Einstein the standard of greatness. However, neither the mystique nor the receptivity can be taken for granted. The near-reverent confidence that people have afforded physics is currently being challenged. What does this suggest for the physics classroom?
Interpreting FCI scores: Normalized gain, preinstruction scores, and scientific reasoning ability
Authors: Coletta Vincent P. , Phillips Jeffrey A.
Published: November 2005

We examined normalized gains and preinstruction scores on the force concept inventory (FCI) for students in interactive engagement courses in introductory mechanics at four universities and found a significant, positive correlation for three of them. We also examined class average FCI scores of 2948 students in 38 interactive engagement classes, 31 of which were from the same four universities and 7 of which came from 3 other schools. We found a significant, positive correlation between class average normalized FCI gains and class average preinstruction scores. To probe this correlation, we administered Lawson’s classroom test of scientific reasoning to 65 students and found a significant, positive correlation between these students’ normalized FCI gains and their Lawson test scores. This correlation is even stronger than the correlation between FCI gains and preinstruction FCI scores. Our study demonstrates that differences in student populations are important when comparing normalized gains in different interactive engagement classes. We suggest using the Lawson test along with the FCI to measure the effectiveness of alternative interactive engagement strategies.
Student understanding of induced current: Using tutorials in introductory physics to teach electricity and magnetism
Authors: Mauk Heidi V. , Hingley Dan
Published: November 2005

Previous research indicates significant improvement in student conceptual understanding of physics topics after instruction with Tutorials in Introductory Physics at the University of Washington, Seattle, Washington. However, assessment of the effectiveness of tutorials at other institutions is crucial. We conducted such a field test at the United States Air Force Academy, Colorado. Students using the tutorials were compared to students using the standard curriculum, students using tutorial pretests only, and students in the honors program. Assessment was based on conceptual questions involving induced current and force. Our results show that students using the tutorials in a modified setting outperformed the control group and rose to the level of performance of the honors students. Our analysis of student reasoning indicates areas where further development of the tutorials is warranted.
HISTORICAL EVOLUTION OF LEGISLATURES IN THE UNITED STATES
Authors: Squire Peverill
Published: November 2005

▪ Abstract  This paper examines the evolution of legislatures in the United States beginning with the establishment of the first assembly in Virginia in 1619. Drawing on works by historians, it traces the development of the colonial assemblies as legislative institutions. The transition of assemblies to state legislatures is investigated, as is the underappreciated impact of the first state legislatures on the rules and structures given to the U.S. Congress in the Constitution. The effects of legislative generations are revealed by the state legislatures established during the nineteenth century, as newer legislatures were equipped from their start with the rules and committee systems evolved only over time by earlier legislatures. The continuing evolution of state legislatures after the nineteenth century is linked to the concept of legislative professionalization. Finally, the relationship between legislative evolution and membership turnover is examined, as is the idea that legislatures move in both directions on the evolutionary dimension.
The Unfolded Protein Response: A Novel Component of the Hypoxic Stress Response in Tumors
Authors: Feldman Douglas E. , Chauhan Vibha , Koong Albert C.
Published: November 2005

Hypoxia is a physiologically important endoplasmic reticulum (ER) stress that is present in all solid tumors. Numerous clinical studies have shown that tumor hypoxia predicts for decreased local control, increased distant metastases, and decreased overall survival in a variety of human tumors. Hypoxia selects for tumors with an increased malignant phenotype and increases the metastatic potential of tumor cells. Tumor cells respond to hypoxia and ER stress through the activation of the unfolded protein response (UPR). The UPR is an adaptive response to increase cell survival during ER stress. XBP-1 is a critical transcriptional regulator of this process and is required for tumor growth. Pancreatic ER kinase (PKR-like ER kinase) regulates the translational branch of the UPR and is also important in the growth of tumors. Although the exact mechanism has yet to be elucidated, recent data suggest that the UPR affects tumor growth through protection from apoptosis and may influence angiogenic signaling pathways. Targeting various components of the UPR is a promising therapeutic strategy. Understanding the relationship between hypoxia, the UPR, and tumor growth is crucial to improving current cancer therapies.
Multitargeted Effects of Statin-Enhanced Thrombolytic Therapy for Stroke With Recombinant Human Tissue-Type Plasminogen Activator in the Rat
Authors: Zhang Li , Zhang Zheng Gang , Ding Guang Liang , Jiang Quan , Liu Xianshuang , Meng He , Hozeska Ann , Zhang Chunling , Li Lian , Morris Dan , Zhang Rui Lan , Lu Mei , Chopp Michael
Published: November 2005

Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type plasminogen activator (rht-PA) constrains the therapeutic window to 3 hours. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) promote vascular thrombolysis and reduce the inflammation response. We therefore investigated the neuroprotective effects of a combination of atorvastatin and delayed rht-PA treatment in a rat model of embolic stroke.

Methods and Results—Rats subjected to embolic middle cerebral artery occlusion were treated with atorvastatin in combination with rht-PA 4 hours after stroke. Magnetic resonance imaging measurements revealed that combination treatment with atorvastatin and rht-PA blocked the expansion of the ischemic lesion, which improved neurological function compared with saline-treated rats. Real-time reverse transcription–polymerase chain reaction analysis of single endothelial cells isolated by laser-capture microdissection from brain tissue and immunostaining showed that combination treatment downregulated expression of tissue factor, von Willebrand factor, protease-activated receptor-1, intercellular adhesion molecule-1, and matrix metalloproteinase-9, which concomitantly reduced cerebral microvascular thrombosis and enhanced microvascular integrity. Combination treatment did not increase cerebrovascular endothelial nitric oxide synthase (eNOS) levels or eNOS activity, and inhibition of NOS activity withN-nitro-l-arginine methyl ester did not block the beneficial effects of combination treatment on stroke. Furthermore, combination treatment compared with thrombolytic monotherapy increased cerebral blood flow and reduced infarct volume in eNOS-null mice.

Conclusions—These data demonstrate that combination treatment with atorvastatin and rht-PA exerts a neuroprotective effect when administered 4 hours after stroke and that the therapeutic benefits are likely attributed to its multitargeted effects on cerebrovascular patency and integrity.
Intravenous Amiodarone for Incessant Tachyarrhythmias in Children
Authors: Saul J. Philip , Scott William A. , Brown Stephen , Marantz Pablo , Acevedo Valeria , Etheridge Susan P. , Perry James C. , Triedman John K. , Burriss Susan W. , Cargo Paul , Graepel Jay , Koskelo Eeva-Kaarina , Wang Rebecca
Published: November 2005

Background—

Intravenous (IV) amiodarone has proven efficacy in adults. However, its use in children is based on limited retrospective data.

Methods and Results—

A double-blind, randomized, multicenter, dose-response study of the safety and efficacy of IV amiodarone was conducted in 61 children (30 days to 14.9 years; median, 1.6 years). Children with incessant tachyarrhythmias (supraventricular arrhythmias [n=26], junctional ectopic tachycardia [JET, n=31], or ventricular arrhythmias [n=4]) were randomized to 1 of 3 dosing regimens (low, medium, or high: load plus 47-hour maintenance) with up to 5 open-label rescue doses. The primary efficacy end point was time to success. Of 229 patients screened, 61 were enrolled during 13 months by 27 of 48 centers in 7 countries. Median time to success was significantly related to dose (28.2, 2.6, and 2.1 hours for the low-, medium-, and high-dose groups, respectively;
P
=0.028). There was no significant association with dose for any arrhythmia subgroup, including JET, but the subgroups were too small for an accurate assessment. Adverse events (AEs) were common (87%), leading to withdrawal of 10 patients. There were 5 deaths in the 30-day follow-up period (2 possibly related to the study drug). Dose-related AEs included hypotension (36%), vomiting (20%), bradycardia (20%), atrioventricular block (15%) and nausea (10%).

Conclusions—

In children, the overall efficacy of IV amiodarone, as measured by time to success, was dose related but not significantly for any arrhythmia subgroup. AEs were common and appeared to be dose related. Although efficacious for critically ill patients, the dose-related risks of IV amiodarone should be taken into account when treating children with incessant arrhythmias. Prospective, placebo-controlled trials would be helpful in assessing antiarrhythmic drug efficacy in children, because their results may differ from retrospective series and adult studies.
Mitochondrial Dysfunction and Apoptosis Underlie the Pathogenic Process in α-B-Crystallin Desmin-Related Cardiomyopathy
Authors: Maloyan Alina , Sanbe Atsushi , Osinska Hanna , Westfall Margaret , Robinson Dustin , Imahashi Ken-ichi , Murphy Elizabeth , Robbins Jeffrey
Published: November 2005

Background—

Mitochondria and sarcomeres have a well-defined architectural relation that partially depends on the integrity of the cytoskeletal network. An R120G missense mutation in the small heat shock protein α-B-crystallin (CryAB) causes desmin-related cardiomyopathy. Desmin-related cardiomyopathy is characterized by the formation of intracellular aggregates containing CryAB and desmin that are amyloid positive, and disease can be recapitulated in transgenic mice by cardiac-specific expression of the mutant protein.

Methods and Results—

To understand the resultant pathology, we explored the acute effects of R120G expression both in vitro and in vivo. In vitro, transfection of adult cardiomyocytes with R120G-expressing adenovirus resulted in altered contractile mechanics. In vivo, as the cytoskeletal network is disturbed but before deficits in organ function can be detected, alterations in mitochondrial organization and architecture occur, leading to a reduction in the maximal rate of oxygen consumption with substrates that utilize complex I activity, alterations in the permeability transition pore, and compromised inner membrane potential. Apoptotic pathways are subsequently activated, which eventually results in cardiomyocyte death, dilation, and heart failure.

Conclusions—

Cardiac chaperone dysfunction acutely leads to altered cardiomyocyte mechanics, perturbations in mitochondrial-sarcomere architecture, and deficits in mitochondrial function, which can result in activation of apoptosis and heart failure.
Comparison of Bare-Metal Stenting With Minimally Invasive Bypass Surgery for Stenosis of the Left Anterior Descending Coronary Artery
Authors: Thiele Holger , Oettel Stefan , Jacobs Stephan , Hambrecht Rainer , Sick Peter , Gummert Jan F. , Mohr Friedrich W. , Schuler Gerhard , Falk Volkmar
Published: November 2005

Background—

Randomized trials comparing stenting with minimally invasive direct coronary artery bypass surgery in patients with isolated proximal left anterior descending lesions have shown a significantly higher reintervention rate for stenting and similar results for mortality and reinfarction at short-term follow-up. Long-term follow-up data are sparse.

Methods and Results—

Patients with isolated proximal left anterior descending stenosis were randomized to either surgery (n=110) or bare-metal stenting (n=110). At 5 years, follow-up data were obtained with respect to the primary end point of death, reinfarction, or repeated target vessel revascularization. Clinical symptoms were assessed by the Canadian Cardiovascular Society (CCS) classification. Follow-up information was completed for 216 patients (98.2%), and mean follow-up was 5.6±1.2 years. With respect to mortality (surgery, 12%; stenting, 10%;
P
=0.54) and reinfarctions (surgery, 7%; stenting, 5%;
P
=0.46), there were no differences between treatment strategies. The need for repeated target vessel revascularization was significantly higher after stenting (32%) compared with surgery (10%;
P
<0.001). Clinical symptoms improved significantly in both treatment groups compared with baseline; however, there was a favorable trend for surgery (stenting: CCS, 2.6±0.9 to 0.5±0.8,
P
<0.001; surgery: CCS, 2.6±0.9 to 0.3±0.6,
P
<0.001;
P
=0.05, stenting versus surgery).

Conclusions—

At the 5-year follow-up, minimally invasive bypass surgery and bare-metal stenting showed similar results for the end points of mortality and reinfarctions. However, the reintervention rate is higher after stenting, and the relief in clinical symptoms is slightly better after surgery.
Elastic Coupling Effects in Tapered Sandwich Panels with Laminated Anisotropic Composite Facings
Authors: Vel Senthil S. , Caccese Vincent , Zhao Huyue
Published: November 2005

A newly developed theory for the analysis of tapered sandwich panels with laminated anisotropic facings is presented. Unlike sandwich panels of uniform depth, the response of tapered sandwich panels is counterintuitive. For example, prior studies have demonstrated that a tapered cantilever sandwich beam having constant dimensions at the clamped edge and subjected to a tip load has an optimum taper angle where the tip deflection is a minimum. The decrease in tip deflection with increasing taper angle, despite the reduction in core thickness, is due to the participation of the facings in resisting transverse shear loads. In the present work, we systematically develop a tapered sandwich theory that is simple to use, yet accurately predicts the stresses and deflection of both symmetric and nonsymmetric tapered sections. A novel feature of the analytical model is that the elastic rigidities of tapered sandwich composites are expressed in terms of the familiar A, B, and D matrices that are widely used to analyze the response of laminated plates and sandwich beams of uniform depth. It is shown that the stiffness matrix for a tapered sandwich member exhibits a total of 12 elastic couplings that are absent in sandwich beams of uniform depth. The analytical model predicts large interlaminar shear and normal stresses near the root of the tapered sandwich beam, which can cause delamination failure between the facings and the core. Numerical results obtained using the tapered sandwich theory and two-dimensional finite element models are in good agreement for several case studies.
Defective Repairs of Laminated Solid Composites
Authors: Hamoush Sameer , Shivakumar Kunigal , Darwish Feras , Sharpe Matthew , Swindell Paul
Published: November 2005

This paper presents an experimental evaluation of the defective patch repairs of solid laminated composites. The study uses both destructive and nondestructive tests on full-scale repaired panels to evaluate the repair performance under static tension loading conditions. While most reported studies use small coupon specimens, this paper presents test results of full-scale panels that allow strain field monitoring around the patch. The experimental results presented in this paper are the baseline for more advanced study to evaluate the performance of defective repairs in severe loading conditions (fatigue) that is underway by the authors. The nondestructive tests are performed by Iowa State University while the destructive tests are performed by North Carolina A&T State University. The testing program consists of 14 panels of six-ply (300 mm 675 mm) ((60/60/0)s) quasi-isotropic laminates: three pristine (undamaged parent material panels), three damaged panels without repair, three good repairs, three defective repairs due to inserted engineered flaw, and two repairs with mismatched fiber orientation. Two types of defective repairs are investigated: inserting 1-in. circular disbond between the sixth ply and the parent material forms the first type while the second type is formed by fiber mismatching between the patch and the parent material. Based on the evaluation performed in this study, the restored tensile strength of both defective and good repairs is within 80% of the strength of the pristine panels.
Characterization of Flexural Properties of Syntactic Foam Core Sandwich Composites and Effect of Density Variation
Authors: Gupta Nikhil , Woldesenbet Eyassu
Published: November 2005

Microballoons (hollow particles) of the same outer radius but with five different inner radius values are used to fabricate five types of syntactic foam slabs. These five types of slabs are used as the core material to fabricate sandwich composites. Three- and four-point bending and short beam shear strength tests are carried out to characterize the flexural behavior of syntactic foam core sandwich composites. The effect of change in microballoon radius ratio (ratio of the inner to the outer radius) on the flexural properties of the sandwich composites is also studied. The results show that in three- and four-point bending tests, the failure is governed by tensile properties of the foam core and the strength is not affected by the microballoon radius ratio. Shear failure takes place in short beam shear tests, which makes the microballoon radius ratio an important factor in determining the strength of the sandwich composite.
Theoretical and Experimental Studies on Residual Stresses in Laminated Polymer Composites
Authors: Shokrieh Mahmood M. , Kamali S. Masoud
Published: November 2005

In this research, the residual stresses in thermoset polymer composites are studied. Generally, these stresses are studied from the macroscopic and microscopic points of view. The main factors responsible for the buildup of these stresses in composite materials are the curing process, moisture, and temperature. The stress-free temperature of various samples of a laminated composite is measured. The macroscopic residual stresses due to the curing process of orthotropic thermoset polymer composites are determined analytically by two methods in addition to an experimental one. The classical lamination theory (CLT) is used for the calculation of residual stresses in each layer of laminated composites. It is shown that the capability of the classical lamination theory in the calculation of the residual stresses without considering the temperature dependent properties is very good. However, the shape of the unsymmetrical laminated specimen at room temperature, calculated by the CLT, is not generally accurate. The energy method is used for the modification of the CLT in predicting the room-temperature shape of the unsymmetrical laminated composites. Experimentally, glass/epoxy and carbon/epoxy laminated composites are studied by the hole drilling method. This method is shown to be reliable for an accurate measurement of the residual stresses in the first layer of laminated composites.
Design, Modeling, Control, and Evaluation of a Hybrid Hip Joint Miniature Climbing Robot
Authors: Krosuri Satya P. , Minor Mark A.
Published: November 2005

The subject of this paper is the design, control, and evaluation of a biped-climbing robot featuring a new hybrid hip joint. The hybrid hip provides both prismatic and revolute motion, discretely, to the robot, using a single actuator. This is intended to improve its adaptability in confined environments and its capability to maneuver over and around obstacles. Optimization of the hybrid hip joint relative to robot size, weight, and actuation limits is considered while maximizing range of motion. The mechanical structure of the robot is discussed, as well as forward and inverse kinematics for motion planning. Reachable robot workspace in both revolute and prismatic phases of the hybrid hip joint is analyzed. Different robot locomotion strides are developed and dynamic controller requirements are considered. Experimental evaluation of the robot walking and climbing on and between surfaces with different inclinations is conducted to evaluate performance and repeatability of the system.
Ground Reference Points in Legged Locomotion: Definitions, Biological Trajectories and Control Implications
Authors: Popovic Marko B. , Goswami Ambarish , Herr Hugh
Published: November 2005

The zero moment point (ZMP), foot rotation indicator (FRI) and centroidal moment pivot (CMP) are important ground reference points used for motion identification and control in biomechanics and legged robotics. In this paper, we study these reference points for normal human walking, and discuss their applicability in legged machine control. Since the FRI was proposed as an indicator of foot rotation, we hypothesize that the FRI will closely track the ZMP in early single support when the foot remains flat on the ground, but will then significantly diverge from the ZMP in late single support as the foot rolls during heel-off. Additionally, since spin angular momentum has been shown to remain small throughout the walking cycle, we hypothesize that the CMP will never leave the ground support base throughout the entire gait cycle, closely tracking the ZMP. We test these hypotheses using a morphologically realistic human model and kinetic and kinematic gait data measured from ten human subjects walking at self-selected speeds. We find that the mean separation distance between the FRI and ZMP during heel-off is within the accuracy of their measurement (0.1% of foot length). Thus, the FRI point is determined not to be an adequate measure of foot rotational acceleration and a modified FRI point is proposed. Finally, we find that the CMP never leaves the ground support base, and the mean separation distance between the CMP and ZMP is small (14% of foot length), highlighting how closely the human body regulates spin angular momentum in level ground walking.
Error Compensation System for Joints, Links and Machine Frame of Parallel Kinematics Machines
Authors: Oiwa Takaaki
Published: November 2005

This paper describes error compensation methods for parallel kinematics machines (PKMs). First, joint errors and link deformations caused by external forces and heat are discussed. Because a linear scale unit is connected to each spherical joint located at both ends of an extensible limb through two rods, the scale unit can measure not only displacement of the prismatic joint but also the limb’s deformation. Moreover, the scale unit also measures the joint’s runout and its deformation in the limb’s direction because the rod end is in contact with the sphere of the spherical joint. Consequently, the unit accurately measures any change in the distance between the spherical joints independent of the external force. Further, temperature fluctuation has little effect on measured distance because the rods are made of a low expansion alloy. This device was built using experimental limbs and tested for use with coordinate measuring machines. Results showed that, without any additional sensor, the device acquired the same effect; it improved the stiffness and the thermal coefficient of expansion of the whole limb. Secondly, another compensation method for elastic and thermal deformations of the machine frame supporting the mechanism is proposed. Nine displacement sensors with Super-Invar rods measure the distance between the surface place and three joint supports or the base platform of the PKM. Then, the forward kinematics of the hexapod mechanism calculates displacement and orientation variations of the base platform during operation from these measured displacements. Consequently, coordinates of the PKM’s end-effector can be compensated by the dimensions, the displacement, and the orientation of the base platform during operation. This device was installed in the experimental coordinate measuring machine. Coordinate measurements using a master ball mounted on the surface plate showed that this device decreased the influences of temperature fluctuation and external force on machine accuracy.
Physico-chemical treatment of Merida landfill leachate for chemical oxygen demand reduction by coagulation
Authors: Méndez-Novelo Roger I. , Castillo-Borges Elba R. , Sauri-Riancho María R. , Quintal-Franco Carlos A. , Giacomán-Vallejos Germán , Jiménez-Cisneros Blanca
Published: November 2005

In order to determine the optimal dosage and type of coagulant for the physico-chemical treatment of leachate from the sanitary landfill of Merida, Mexico, a total of 864 jar tests were performed. Four metallic coagulants (ferric chloride, ferric sulphate, aluminium polychloride and aluminium sulphate) with doses ranging between 50 and 300 mg L-1 and two polyelectrolytes (high-density anionic and cationic reagents) with doses from 2 to 12 mg L-1 were tested. Neither an adequate type of coagulant nor an optimal dose could be found. The removal of contaminants was measured as total and dissolved chemical oxygen demand (COD). Soluble COD removal efficiencies were low, from 0 to 47%, with a 4% average value only. These low values of organic material removal were attributed to the particular characteristics of the Merida landfill leachate (low suspended solids concentration), so even with sweep-floc coagulation (300 mg L-1 dose) only low COD removal efficiencies were obtained. A study of the suspended particle size distribution of the leachate was conducted in order to explain the poor performance. The particle size distribution ranged from 0.375 to 948.2 μm, with an average value of 22.97 μm. In a second step the optimal pH for physico-chemical treatment of these leachates was determined. Finally a greater than 90% removal of organic material, measured as suspended COD, was obtained at pH 2, which was considered as the optimal value.
Comparison of external costs between dry tomb and bioreactor landfills: taking intergenerational effects seriously
Authors: Méry Jacques , Bayer Stefan
Published: November 2005

Dry tomb and bioreactor landfills were analyzed with respect to their external costs in an intergenerational cost-benefit analysis in a partial framework which enabled a sounder comparison to be carried out between these two technologies from a socio-economic viewpoint. Obviously, this approach was only a first step for building a comprehensive basis of any environmental as well as fiscal policy in the field of waste management. All external costs are identified and evaluated in three different scenarios, corresponding to a worst case, a best guess and a best case. Obviously, discounting is crucial with respect to an intergenerational perspective. Generation-adjusted discounting (GAD) was applied to take into account equity as well as efficiency criteria, in order to deal with three different types of uncertainties that are decisive in waste policy decisions: a physical uncertainty is captured by introducing our three different scenarios; a macroeconomic uncertainty is taken into consideration by calculating present values using different real growth rates; and a microeconomic uncertainty is taken into account by considering individual peculiarities reflected in their subjective time preference rate. The findings show, that whenever there is a low real GDP growth of less than 1%, the bioreactor is generally superior to the dry tomb (lower present values of external costs). This statement becomes more valid as the growth rate decreases. However, whenever there are high positive growth rates, it is the dry tomb technology which is superior to the bioreactor system.
Separation of fine binary mixtures under vibration in a gas-solid fluidized bed with dense medium
Authors: Jin Haibo , Tong Zemin , Schlaberg H. Inaki , Zhang Jiyu
Published: November 2005

The coke-slag mixture discharged from water-air generators not only causes a serious environmental problem, but also is a potential resource. In order to obtain a high economic return, separation of fine binary mixtures in a vibrating fluidized bed with dense media was experimentally investigated. The effects of volume ratio (mono-component volume to dense medium volume or binary mixture volume to dense medium volume), the fluidization velocity and vibration parameters on separation efficiency are discussed. The experimental results show that vibration can prevent the coalescence and growth of bubbles and improve fluidization properties of particles and the stability of bed density. The major factors associated with separating efficiency are discussed. Based on the experiments, the ratio of the volume of particles to bed volume and the vibration conditions are also reported. It was found that the separation efficiency for a fine coke-slag mixture was greater than 70% and close to 80% under optimal conditions.