bluuebunny/crossref_metadata_2025 huggingface dataset:
When trade liberalization turns into regulatory reform: The impact on business–government relations in international trade politics
Authors: Woll Cornelia , Artigas Alvaro
Published: May 2007

Business–government relations on trade issues are generally characterized as protectionist lobbying or – less often – lobbying for the liberalization of markets. However, with the evolution of the trading system, negotiations today concern not just market opening, but also the regulatory frameworks that structure international trade. This transformation has important consequences for the ways in which private interests can contribute to trade negotiations. Instead of simply trying to exert pressure, businesses and other private actors now form working relationships with governments based on expertise, learning, and information exchange. This article illustrates these new forms of public–private interactions with examples from the USA, the European Union, and Brazil.
Acute Toxicity and Sublethal Effects of Nitrite on Selected Hematological Parameters and Tissues in Dark‐banded Rockfish, Sebastes inermis
Authors: Park In‐Seok , Lee Jinhwan , Hur Jun‐Wook , Song Young‐Chae , Na Hae Choon , Noh Choong Hwan
Published: May 2007

Acute toxicity and sublethal effects of nitrite in dark‐banded rockfish, Sebastes inermis (83.3 ± 7.2 g), were studied under static conditions for a period of 96 h. The acute toxicity of nitrite evaluated for the 96‐h lethal concentration (LC50) was 700 mg/L. The sublethal effects on selected hematological parameters of S. inermis, such as total erythrocyte count (TEC), hemoglobin, plasma glucose, and serum protein content, were measured after 0, 6, 12, 24, 48, 72, and 96 h of exposure to 0, 50, 100, 200, 400, and 700 mg/L of nitrite. Sublethal nitrite caused progressive reduction in the TEC, hemoglobin, and serum protein content in fish depending on the nitrite concentration and exposure period. The 96‐h exposure resulted in a 14–42% reduction in TEC and 25–33% reduction in hemoglobin content for 100–700 mg/L of nitrite compared to the control. A dose‐related reduction in plasma glucose (25.7–34.2%) was observed for concentrations of 200–700 mg/L of nitrite during 48 h of exposure, followed by an increase through 96 h. A significant reduction in serum protein (7.3–12.6%) was observed for 200–700 mg/L of nitrite after 96 h of exposure. Abnormal histological changes in skin, gill, liver, and kidney tissue were observed in fish exposed to 700 mg/L of nitrite after 96 h of exposure compared to the control. Although no mortality of S. inermis occurred at 500 mg/L of nitrite, all hematological parameters adversely responded to a nitrite dose of 200 mg/L for 96 h. These results showed that although acute toxicity concentration of nitrite in S. inermis is higher than 700 mg/L, sublethal concentrations of nitrite also negatively affect hematological parameters.
Induced Spawning and Egg Quality Evaluation of Red Snapper, Lutjanus campechanus
Authors: Bourque Bradford D. , Phelps Ronald P.
Published: May 2007

Brood red snapper, Lutjanus campechanus, were captured from the wild and induced to ovulate by human chorionic gonadotropin (hCG) injection; eggs and sperm were manually stripped; and the eggs were artificially fertilized. Eggs were evaluated by the following egg quality parameters: buoyancy, fertilization, egg size, and oil globule size and number. The relationship of these egg quality parameters and brood characteristics (female size, fecundity, time of year, and response time to ovulation) to 36 h posthatch larval survival was considered. Injection of wild‐caught red snapper females with 1100 IU/kg of hCG resulted in 75% of the females ovulating. The average fecundity was 343,377 ± 30,805 eggs/kg, with a mean percent fertilization of 79.0 ± 1.74%. The mean percentage of floating eggs per spawn was 91.8 ± 1.75%. Mean egg diameter for floating eggs was 778.3 ± 2.09 μm, with a mean oil globule diameter of 117.5 ± 1.53 μm. Brood‐related characteristics were a better predictor of larval survival than postovulation egg characteristics. The percentage of floating eggs in a spawn was not correlated to larval survival. Spawns with eggs having a single oil globule had a similar larval survival as those eggs where multiple globules were common. No clear relationships were found for any one factor and larval survival, but rather a combination of factors was more predictive of survival, most notably spawn date, fecundity, and response time following hCG injection.
Interactions of Dietary Microbial Phytase, Citric Acid and Crude Protein Level on Mineral Utilization by Rohu, Labeo rohita (Hamilton), Juveniles
Authors: Baruah Kartik , Sahu Narottam P. , Pal Asim K. , Debnath Dipesh , Yengkokpam Sona , Mukherjee Subhas C.
Published: May 2007

A 2 × 2 × 2 factorial experiment was designed to study the effect of microbial phytase (MP), citric acid (CA), and crude protein (CP) and their interactions on mineral utilization by rohu, Labeo rohita, juveniles. Two basal diets containing 25% (subnormal) or 35% (normal) CP were supplemented with MP (units, U/kg) and CA (%) at 0, 0; 500, 0; 0, 3; and 500, 3, respectively and fed to 125 juveniles (average initial weight: 13.16 g/fish). MP did not affect fecal ash content but CA (3%) addition activated MP. Apparent absorption of Zn, its content in whole body and plasma, was significantly (P < 0.05) higher in CA‐ and MP‐fed groups. Interaction between CA and MP was found for increased absorption of Na, P, K, Mn, Mg, Fe, and N, their concentrations in whole body and plasma. Cu and Ca absorption, and their concentration in body and plasma were increased as a result of addition of CA, MP, or their interaction. Thus, bioavailability of major minerals was highest in groups fed diets containing 500‐U MP and 3% CA. This improvement was more prominent in subnormal CP diet. Growth performance was also highest in this group. Thus, CA and MP at 25% CP diet had synergistic effect on mineral bioavailability in L. rohita.
Stability of Formulated Diets and Feeding Response of Stage I Western Spiny Lobster, Panulirus cygnus, Phyllosomata
Authors: Johnston Matthew D. , Johnston Danielle J
Published: May 2007

This study is a preliminary assessment of suitable binders and formats of potential formulated diets for hatchery growout of early‐stage western spiny lobster, Panulirus cygnus, phyllosomata. Six dry meal (each bound with a different binder) and three gelatinous (all bound using gelatine) diets were tested for stability in water over increasing periods of time (4, 8, and 12 h), and the feeding response to each was observed by video analysis. The gelatinous krill diet appears most suited to the larval feeding biology of P. cygnus phyllosomata as it elicited a heightened feeding response immediately following immersion, was most stable in water up to 4 h, and did not foul the maxillae during ingestion. The dry meal diets were not as stable in water and contributed to excessive fouling of the maxillae during ingestion. Of the dry meal diets, the most suitable was bound with 5% k‐carrageenan, presumably because of high moisture content and softer texture.
Kinetics of Cellular Component in Inflammatory Response Induced by Different Stimuli in the Swim Bladder of Pacu, Piaractus mesopotamicus Holmberg 1887 (Characidae)
Authors: Bozzo F. R. , Moraes J. R. E. , Ruasde Moraes Flávio , Pereira G. T. , Tavares‐Dias M. , Onaka E. M.
Published: May 2007

Abstract.— The present study assessed the kinetics of cell accumulation at the site of inflammation induced by thioglycolate, Escherichia coli lipopolysaccharide (LPS) and heat‐inactivated Aeromonas hydrophila, in the pacu, Piaractus mesopotamicus (Characidae), swim bladder. A quantitative, as well as qualitative, assessment was done of all the cells present in the exudate at 6, 24, and 48 h (n = 8) after inoculation of inflammatory agents. The results show that the thioglycolate was the irritant to induce higher total inflammatory cell accumulation when compared to the control group, 6 h after insult (P < 0.05). Inoculation of heat‐inactivated Aeromonas hydrophila induced progressive accumulation of total inflammatory cells, with cell number peaking after 24 h and being significantly higher than observed in the other groups (P < 0.05). Injection of LPS also induced greater cell accumulation when compared to the control group (P < 0.05), although in lower numbers than those induced by the other two irritants. All irritants injected induced significantly greater accumulation of lymphocytes and thrombocytes when compared to the control group (P < 0.05).
Avian influenza and poultry workers, Peru, 2006
Authors: Ortiz Ernesto J. , Kochel Tadeusz J. , Capuano Ana W. , Setterquist Sharon F. , Gray Gregory C.
Published: May 2007

Background  Currently numerous countries in Asia, Africa and Europe are encountering highly pathogenic avian influenza (AI) infections in poultry and humans. In the Americas, home of the world’s largest poultry exporters, contingency plans are being developed and evaluated in preparation for the arrival of these viral strains.

Objectives  With this cross‐sectional study, to our knowledge the first in its kind in Central or South America, we sought to learn whether Peruvian poultry workers had evidence of previous AI infection and if so, to determine the risk factors for infection.

Methods  We performed a cross‐sectional seroprevalence study among 149 workers on a Peruvian poultry farm (132 exposed to poultry and 17 non‐exposed controls), serum samples were tested for human influenza virus exposure using a hemagglutination inhibition (HI) assay. Microneutralization assays were performed on all serum samples to detect antibodies against prototypic AI strains H4 through H12.

Results  Using multivariate proportional odds modeling we found that the prevalence of elevated titers against AI viruses was low in both groups, exposed and non‐exposed controls.

Conclusions  No evidence of previous AI infection among Peruvian poultry workers was found in this first cross‐sectional study performed in South America. This first occupational study of AI in Latin America was encouraging, but it likely reflects the sector of poultry production with higher biosecurity.
Protection against mouse and avian influenza A strains via vaccination with a combination of conserved proteins NP, M1 and NS1
Authors: Zhirnov Oleg P. , Isaeva Elena I. , Konakova Tatyana E. , Thoidis Galini , Piskareva Lyudmila M. , Akopova Irina I. , Kartashov Alex , Altstein Anatoly D. , Ilyinskii Petr O. , Shneider Alexander M.
Published: May 2007

Background  Experimental data accumulated over more than a decade indicate that cross‐strain protection against influenza may be achieved by immunization with conserved influenza proteins. At the same time, the efficacy of immunization schemes designed along these lines and involving internal influenza proteins, mostly NP and M1, has not been sufficient.

Objective  To test the immunogenicity and protective efficacy of DNA vaccination with a combination of NP, M1 and NS1 genes of influenza virus.

Methods  The immunogenicity and protective efficacy of DNA vaccination with NP, M1 and NS1 was tested in mice and chickens. Mice were challenged with mouse‐adapted viral strains H3N2 and H5N2 and chicken challenged with avian H5N3 virus.

Results  In these settings, wild‐type NS1 did not impede the cellular and humoral response to NP/M1 immunization in vivo. Moreover, addition of NS1‐encoding plasmid to the NP/M1 immunization protocol resulted in a significantly increased protective efficacy in vivo.

Conclusions  The addition of NS1 to an influenza immunization regimen based on conserved proteins bears promise. It is feasible that upon further genetic modification of these and additional conserved influenza proteins, providing for their higher safety, expression and immunogenicity, a recombinant vaccine based on several structural and non‐structural proteins or their epitopes will offer broad anti‐influenza protection in a wide range of species.
Vaccines for an influenza pandemic: scientific and political challenges
Authors: Haaheim Lars R.
Published: May 2007

So far, most published results from clinical trials using various avian influenza virus vaccine formulations have been disappointing. Should the pandemic strike, we still do not have the ability to provide an efficacious pandemic vaccine in time and in sufficient quantities for the world. The H5N1 enzootic could potentially give rise to a pandemic at any time. Transcontinental air traffic could seed the pandemic virus to most corners of the globe within a few weeks/months. We still have a unique window of opportunity to stimulate and support academia and the pharmaceutical industry to accelerate the urgently needed vaccine research. The political inertia is surprising, particularly as politicians, if and when a pandemic eventuates, will be asked why, despite repeated warnings, they did not take appropriate action in time. It is a governmental obligation – and not that of the WHO or the pharmaceutical industry – to protect their nationals. Moreover, when the poorer nations of this world realize that equitable quantities of the scarce supplies of vaccines, drugs and medical essentials will not come their way, the post‐pandemic international scene will be one of even more deep distrust for many years. This scenario is not acceptable.
Managing the Commons Texas Style: Wildlife Management and Ground‐Water Associations on Private Lands1
Authors: Wagner Matthew , Kaiser Ronald , Kreuter Urs , Wilkins Neal
Published: May 2007

Abstract:  As nearly all of Texas’ rural lands are privately owned, landowner associations for the management of white‐tailed deer and ground‐water have become increasingly popular. Deer are a common‐pool resource with transboundary characteristics, requiring landowner cooperation for effective management. Ground‐water reserves are economically important to landowners, but are governed by the “rule of capture” whereby property rights are not defined. One ground‐water association and four wildlife management associations (WMAs) were surveyed to characterize their member demographics, land use priorities, attitudes, and social capital. Members of the ground‐water cooperative were part of a much larger, more heterogeneous, and more recently formed group than members of WMAs. They also placed greater importance on utilitarian aspects of their properties, as opposed to land stewardship for conservation as practiced by members of WMAs. If ground‐water association members could be more locally organized with more frequent meetings, social capital and information sharing may be enhanced and lead to land stewardship practices for improved hydrologic functions and sustained ground‐water supply. This, coupled with pumping rules assigned by the local ground‐water district, could yield an effective strategy that is ecologically and hydrologicaly sound, and that allows rural provision of water supply to urban consumers.
History and Development of the NRCS Lag Time Equation1
Authors: Folmar Norman D. , Miller Arthur C. , Woodward Donald E.
Published: May 2007

Abstract:  Many of the hydrologic methods that are used in engineering practice today resulted from the Spring Flood of 1936, which blanketed the Northeastern portion of the United States. Because of the flood damage that was caused by this rainfall‐snowmelt event, many federal agencies including the U.S. Army Corp of Engineers and the Soil Conservation Service (SCS) implemented the hydrologic theories that were available in the literature at this time and developed hydrologic procedures for design flow estimation. Sherman had recently published his unit hydrograph theory in 1932, and later in 1938 Snyder, who had been charged by the Water Resource Council to develop a synthetic unit hydrograph, published his famous paper. The SCS unit hydrograph theory was developed by Victor Mockus in the late 1950s. Most if not all of the theories at that time reported the rainfall‐runoff process for floods as a surface phenomenon, and as such those theories all required some type of a timing parameter to estimate watershed response time. This article documents the development of the SCS lag equation.
Resurgent Na+ current in pyramidal neurones of rat perirhinal cortex: axonal location of channels and contribution to depolarizing drive during repetitive firing
Authors: Castelli Loretta , Biella Gerardo , Toselli Mauro , Magistretti Jacopo
Published: May 2007

The perirhinal cortex (PRC) is a supra‐modal cortical area that collects and integrates information originating from uni‐ and multi‐modal neocortical regions and directed to the hippocampus. The mechanisms that underlie the specific excitable properties of the different PRC neuronal types are still largely unknown, and their elucidation may be important in understanding the integrative functions of PRC. In this study we investigated the expression and properties of resurgent Na+ current (INaR) in pyramidal neurones of rat PRC area 35 (layer II). Patch‐clamp experiments in acute PRC slices were first carried out. A measurable INaR was expressed by a large majority of neurones (31 out of 35 cells). INaR appeared as an inward, slowly decaying current elicited upon step repolarization after depolarizations sufficient to induce nearly complete inactivation of the transient Na+ current (INaT). INaR had a peak amplitude of ∼2.5% that of INaT, and showed the typical biophysical properties also observed in other neuronal types (i.e. cerebellar Purkinje and granule cells), including a bell‐shaped current–voltage relationship with a peak at approximately −40 mV, and a characteristic acceleration of activation and decay speed at potentials negative to −45 mV. Current‐clamp experiments were then carried out in which repetitive action‐potential discharge at various frequencies was induced with depolarizing current injection. The voltage signals thus obtained were then used as command waveforms for voltage‐clamp recordings. These experiments showed that a Na+ current identifiable as INaR activates in the early interspike phase even at relatively high firing frequencies (20 Hz), thereby contributing to the depolarizing drive and possibly enhancing repetitive discharge. In acutely dissociated area 35 layer II neurones, as well as in nucleated patches from the same neurones, INaR was never observed, despite the presence of typical INaTs. Since in both preparations neuronal processes are lost, we carried out experiments of focal tetrodotoxin (TTX) application in slices to verify whether the channels responsible for INaR are located in compartment(s) different from the soma. We found that TTX preferentially inhibited INaR when applied close to the site of axon emergence from soma, whereas application to the apical pole of the soma had a significantly smaller effect on INaR. Our results indicate that in area 35 pyramidal cells INaR is largely generated in the axon initial segment, where it may participate in setting the coding properties of these neurones.
Constitutive Material Modeling of Cell: A Micromechanics Approach
Authors: Unnikrishnan G. U. , Unnikrishnan V. U. , Reddy J. N.
Published: May 2007

The variations in mechanical properties of cells obtained from experimental and theoretical studies can be overcome only through the development of a sound mathematical framework correlating the derived mechanical property with the cellular structure. Such a formulation accounting for the inhomogeneity of the cytoplasm due to stress fibers and actin cortex is developed in this work. The proposed model is developed using the Mori-Tanaka method of homogenization by treating the cell as a fiber-reinforced composite medium satisfying the continuum hypothesis. The validation of the constitutive model using finite element analysis on atomic force microscopy (AFM) and magnetic twisting cytometry (MTC) has been carried out and is found to yield good correlation with reported experimental results. It is observed from the study that as the volume fraction of the stress fiber increases, the stiffness of the cell increases and it alters the force displacement behavior for the AFM and MTC experiments. Through this model, we have also been able to find the stress fiber as a likely cause of the differences in the derived mechanical property from the AFM and MTC experiments. The correlation of the mechanical behavior of the cell with the cell composition, as obtained through this study, is an important observation in cell mechanics.
The Nonlinear Material Properties of Liver Tissue Determined From No-Slip Uniaxial Compression Experiments
Authors: Roan Esra , Vemaganti Kumar
Published: May 2007

The mechanical response of soft tissue is commonly characterized from unconfined uniaxial compression experiments on cylindrical samples. However, friction between the sample and the compression platens is inevitable and hard to quantify. One alternative is to adhere the sample to the platens, which leads to a known no-slip boundary condition, but the resulting nonuniform state of stress in the sample makes it difficult to determine its material parameters. This paper presents an approach to extract the nonlinear material properties of soft tissue (such as liver) directly from no-slip experiments using a set of computationally determined correction factors. We assume that liver tissue is an isotropic, incompressible hyperelastic material characterized by the exponential form of strain energy function. The proposed approach is applied to data from experiments on bovine liver tissue. Results show that the apparent material properties, i.e., those determined from no-slip experiments ignoring the no-slip conditions, can differ from the true material properties by as much as 50% for the exponential material model. The proposed correction approach allows one to determine the true material parameters directly from no-slip experiments and can be easily extended to other forms of hyperelastic material models.
Long Durations of Immobilization in the Rat Result in Enhanced Mechanical Properties of the Healing Supraspinatus Tendon Insertion Site
Authors: Gimbel J. A. , Van Kleunen J. P. , Williams G. R. , Thomopoulos S. , Soslowsky L. J.
Published: May 2007

Rotator cuff tears frequently occur and can lead to pain and decreased shoulder function. Repair of the torn tendon back to bone is often successful in relieving pain, but failure of the repair commonly occurs. Post-operative activity level is an important treatment component that has received minimal attention for the shoulder, but may have the potential to enhance tendon to bone healing. The objective of this study was to investigate the effect of short and long durations of various activity levels on the healing supraspinatus tendon to bone insertion site. Rotator cuff tears were surgically created in Sprague–Dawley rats by detaching the supraspinatus tendon from its insertion on the humerus and these tears were immediately repaired back to the insertion site. The post-operative activity level was controlled through shoulder immobilization (IM), cage activity (CA), or moderate exercise (EX) for durations of 4 or 16 weeks. The healing tissue was evaluated utilizing biomechanical testing and a quantitative polarized light microscopy method. We found that activity level had no effect on the elastic properties (stiffness, modulus) of the insertion site at four weeks post injury and repair, and a decreased activity level had a positive effect on these properties at 16 weeks (IM>CA=EX). Furthermore, a decreased activity level had the greatest positive effect on these properties over time (IM>CA=EX). The angular deviation of the collagen, a measure of disorganization, was decreased with a decrease in activity level at 4 weeks (IM<CA=EX), but was similar between groups at 16 weeks (IM=CA=EX). It appears from this study that decreasing the activity level by immobilizing the shoulder improves tendon to bone healing, which progresses by first increasing the organization of the collagen and then increasing the mechanical properties. Future studies in this area will investigate the effect of passive motion and remobilization on both tendon to bone healing and shoulder function.
Computational Model for the Transition From Peristaltic to Pulsatile Flow in the Embryonic Heart Tube
Authors: Taber Larry A. , Zhang Jinmei , Perucchio Renato
Published: May 2007

Early in development, the heart is a single muscle-wrapped tube without formed valves. Yet survival of the embryo depends on the ability of this tube to pump blood at steadily increasing rates and pressures. Developmental biologists historically have speculated that the heart tube pumps via a peristaltic mechanism, with a wave of contraction propagating from the inflow to the outflow end. Physiological measurements, however, have shown that the flow becomes pulsatile in character quite early in development, before the valves form. Here, we use a computational model for flow though the embryonic heart to explore the pumping mechanism. Results from the model show that endocardial cushions, which are valve primordia arising near the ends of the tube, induce a transition from peristaltic to pulsatile flow. Comparison of numerical results with published experimental data shows reasonably good agreement for various pressure and flow parameters. This study illustrates the interrelationship between form and function in the early embryonic heart.
Convective Cooling of a PCB Like Surface With Mixed Heating
Conditions in a Vertical Channel
Authors: Yadav Vipin , Kant Keshav
Published: May 2007

Printed circuit boards (PCBs) with uniform surface temperature and uniform wall heat flux are ideal to study. However, in reality, the heating conditions existing on the PCB surfaces are much different from the ideal ones. Present attempts have been made to study different combinations of uniform heat flux (UHF) and uniform wall temperature (UWT) heating conditions on a single surface and to develop more realistic relationships between various flow and thermal parameters for evaluating the local and averaged Nusselt number. Both the numerical and experimental investigations were undertaken to study partial and mixed UHF and UWT heating conditions on a buoyancy assisted convection cooling of simulated PCB forming one wall of the vertical channel while, the other wall was kept insulated. The current work considers moderate to high flow Reynolds number (14.1×103≤Re≤2.35×105) in the channel and range of heat fluxes near that occurring in electronic cooling applications using air as a coolant (0.0<q≤5.0W∕cm2). Data for heat flux and Nusselt number occurring at various locations of the plate surface under different heating conditions are presented to analyze variation patterns; and an empirical relation is put forward which is capable of predicting Nu under the heating conditions mentioned. The empirical expression obtained can be used for getting an optimized layout of the PCBs inside the equipment cabinet, thus resulting in better design for more reliable and safe operation under potentially harsh environment and/or maximum load condition.
A Novel Anisotropic Conductive Adhesive for Lead-Free Surface Mount
Electronics Packaging
Authors: Ramkumar S. Manian , Srihari Krishnaswami
Published: May 2007

The electronics industry, in recent years, has been focusing primarily on product miniaturization and lead-free assembly. The need for product miniaturization is due to the continuous demand for portable electronic products that are multifunctional, yet smaller, faster, cheaper, and lighter. This is forcing the industry to design and assemble products with miniature passive and active devices. These devices typically have fine pitch footprints that provide a very small surface area for attachment. The solder attach technique relies primarily on the formation of intermetallics between the mating metallic surfaces. With a reduction in the surface area of the pads, the ratio of intermetallic to solder is very high once the solder joint is formed. This could result in unreliable solder joints, due to the brittle nature of intermetallics. In addition, the need to eliminate lead-based materials as a means of interconnection has renewed the industry’s interest in exploring other means of assembling surface mount devices reliably. The use of a novel anisotropic conductive adhesive (ACA) as a means for assembling surface mount devices, the ACA’s performance characteristics, and preliminary research findings are discussed in this paper. Typically, ACAs require the application of pressure during the curing process to establish the electrical connection. The novel ACA uses a magnetic field to align the particles in the Z-axis direction and eliminates the need for pressure during curing. The formation of conductive columns within the polymer matrix provides a very high insulation resistance between adjacent conductors. The novel ACA also enables mass curing of the adhesive, eliminating the need for sequential assembly. The novel ACA was found to be very effective in providing the interconnection for surface mount technology (SMT) passives and leaded, bumped, or bumpless integrated circuit packages. The requirement for precise stencil printing was eliminated, as the application of magnetic field aligned the conductive columns in the Z-axis direction eliminating any lateral conductivity. The ability to mass cure the adhesive while applying the magnetic field reduced the assembly time considerably. Placement accuracy was still found to be very critical. Shear testing of adhesive joints after thermal aging showed significance past 500 h and after temperature–humidity aging showed significance within the first 100 h. I–V characteristics of the daisy chained ball grid array devices assembled with and without bumps revealed considerable difference in the breakdown current. The correlation between initial contact resistance of the daisy chain and the final breakdown current was also determined. Preliminary experiments and findings, discussed in this paper, show the viability of the ACA for mixed SMT assembly. Further experimentations will include in situ contact resistance measurements during thermal aging, temperature–humidity aging, drop testing and thermal shock.
A Global–Local Approach for Mechanical Deformation and Fatigue
Durability of Microelectronic Packaging Systems
Authors: Zhang T. , Rahman S. , Choi K. K. , Cho K. , Baker P. , Shakil M. , Heitkamp D.
Published: May 2007

This paper presents a global–local methodology for predicting mechanical deformation and fatigue durability of solder joints in electronic packaging systems subject to cyclic thermal loading. It involves a global deformation analysis, a local critical solder–joint analysis, and a fatigue life analysis. The global deformation analysis includes a new optimization formulation for determining an equivalent model. The methodology developed was applied to fine pitch ball grid array (fpBGA) and super ball grid array (SBGA) packages. Selective experimental efforts were also undertaken to evaluate the predicted deformation characteristics of the fpBGA package. A good agreement was obtained between the simulated deformation results and experimental observations. For the durability analysis, the total fatigue life predicted using the energy-based method is larger than 2500 cycles—a trend observed experimentally for both packages entailing widely different designs. Based on proposed modeling and simulation results and package designs studied, the SBGA package is more durable than the fpBGA package.
Efficient Cooling of Multiple Components in a Shielded Circuit
Pack
Authors: Hodes Marc , Bolle Cristian , Kolodner Paul
Published: May 2007

We describe a technology in which multiple components inside a circuit pack shielded from electromagnetic interference (EMI) are efficiently cooled by individual heat sinks that protrude into an external airflow through openings in the lid of the shield. Compliant, electrically conductive gaskets are used to form perimeter seals between the bases of the heat sinks and the lid of the enclosure. The gaskets accommodate variations in the heights of the components and allow solid-to-solid contact in the thermal-grease-filled interface between the components and their heat sinks without compromising EMI shielding. This technology provides efficient cooling because the heat sinks can be tailored to the thermal loads of the individual components. Moreover, a set of small heat sinks presents a lower flow resistance to the cooling airflow than the conventional configuration of fins covering the entire lid of an EMI shield. We have examined the implementation of this solution by numerical modeling and by experiment. It leads to acceptable thermal performance, and lower flow resistance relative to the conventional approach. It may reduce cost and weight and it eases rework.
Development of a Strain Transferring Sensor Housing for a Lumbar Spinal Fusion Detection System
Authors: Aebersold J. W. , Hnat W. P. , Voor M. J. , Puno R. M. , Jackson D. J. , Lin J. T. , Walsh K. M. , Naber J. F.
Published: May 2007

Lumbar arthrodesis or spinal fusion is usually performed to relieve back pain, and regain functionality from degenerative disc disease, trauma, etc. Fusion is determined from radiographic images (X-ray) or computed tomography scans, yet these inspection procedures are subjective methods of review. As a result, exploratory surgery is performed if the presence of fusion cannot be confirmed. Therefore, a need exists to provide objective data to determine the presence of fusion that could avoid the cost, pain, and risk of exploratory surgery. One method to achieve this objective is to observe bending strain from spinal rods implanted during surgery. A system has been developed that will attach to the spinal instrumentation rods, transmit strain information wirelessly, and without the use of batteries. Major components of the system include a strain transferring sensor housing, a microelectromechanical (MEMS)-based strain sensor, telemetry circuitry, and antennae. Only discussed herein are the design, testing, and results of the housing without a cover and its ability to transfer strain from the rod to an internal surface where a foil strain gage is attached to characterize strain transfer efficiency. Strain gauges rather than the MEMS sensor were employed for housing characterization due cost and limited availability. Design constraints for the housing are long-term implantation, small size, greater than 95% transfer of bending strain from the spinal rods to the internal strain sensor, and ease of installation. ABAQUS finite element modeling software was employed to develop a working model that was fabricated using polyetheretherkeytone. The housing underwent cycle testing in a material testing system to simulate long-term implantation along with static testing to determine if creep was present. Both series of tests showed that the housing’s response did not degrade over a period of time and there was no indication of creep. The experimental results also validated the results of the ABAQUS finite element model.
Determining Fall Direction and Impact Location for Various Disturbances and Gait Speeds Using the Articulated Total Body Model
Authors: Smeesters Cécile , Hayes Wilson C. , McMahon Thomas A.
Published: May 2007

Because fall experiments with volunteers can be both challenging and risky, especially with older volunteers, we wished to develop computer simulations of falls to provide a theoretical framework for understanding and extending experimental results. To perform a preliminary validation of the articulated total body (ATB) model for passive falls, we compared the model predictions of fall direction, impact location, and impact velocity as a function of disturbance type (faint, slip, step down, trip) and gait speed (fast, normal, slow) to experimental results with young adult volunteers. The three-dimensional ATB model had 17 segments and 16 joints. Its physical characteristics, environment definitions, contact functions, and initial conditions were representative of our experiment. For each combination of disturbance and gait speed, the ATB model was left to fall passively under gravity once disturbed, i.e., no joint torques were applied, until impact with the floor occurred. Finally, we also determined the sensitivity of the model predictions to changes in the model’s parameters. Our model predictions of fall angles and impact angles were qualitatively in agreement with those observed experimentally for ten and seven of the 12 original simulations, respectively. Quantitatively, the model predictions of fall angles, impact angles, and impact velocities were within one experimental standard deviation for seven, three, and nine of the 12 original simulations, respectively, and within two experimental standard deviations for ten, nine, and 11 of the 12 original simulations, respectively. Finally, the fall angle and impact angle region did not change for 92% and 95% of the 74 input variation simulations, respectively, and the impact velocities were within the experimental standard deviations for 78% of the 74 input variation simulations. Based on our simulations and a sensitivity analysis, we conclude that our preliminary validation of the ATB model for passive falls was successful. In fact, these ATB model simulations represent a significant step forward in fall simulations. We believe that with additional work, the ATB model could be used to accurately simulate a variety of human falls and may be useful in further understanding the etiology and mechanisms of fall injuries such as hip fractures.
Forces and Bond Dynamics in Cell Adhesion
Authors: Evans Evan A. , Calderwood David A.
Published: May 2007

Adhesion of a biological cell to another cell or the extracellular matrix involves complex couplings between cell biochemistry, structural mechanics, and surface bonding. The interactions are dynamic and act through association and dissociation of bonds between very large molecules at rates that change considerably under stress. Combining molecular cell biology with single-molecule force spectroscopy provides a powerful tool for exploring the complexity of cell adhesion, that is, how cell signaling processes strengthen adhesion bonds and how forces applied to cell-surface bonds act on intracellular sites to catalyze chemical processes or switch molecular interactions on and off. Probing adhesion receptors on strategically engineered cells with force during functional stimulation can reveal key nodes of communication between the mechanical and chemical circuitry of a cell.
An On-Demand Coherent Single-Electron Source
Authors: Fève G. , Mahé A. , Berroir J.-M. , Kontos T. , Plaçais B. , Glattli D. C. , Cavanna A. , Etienne B. , Jin Y.
Published: May 2007

We report on the electron analog of the single-photon gun. On-demand single-electron injection in a quantum conductor was obtained using a quantum dot connected to the conductor via a tunnel barrier. Electron emission was triggered by the application of a potential step that compensated for the dot-charging energy. Depending on the barrier transparency, the quantum emission time ranged from 0.1 to 10 nanoseconds. The single-electron source should prove useful for the use of quantum bits in ballistic conductors. Additionally, periodic sequences of single-electron emission and absorption generate a quantized alternating current.
Who Watches the Watcher?
Authors: Adami Christoph C.
Published: May 2007

I Am a Strange Loop
.
By Douglas Hofstadter
. Basic Books, New York, 2007. 436 pp. $26.95, C$32.50. ISBN 9780465030781.

Hofstadter blends philosophy, cognition, neural networks, mathematical logic, music, architecture, and physics in a discussion of consciousness and the meaning of life.
Probing Transcription Factor Dynamics at the Single-Molecule Level in a Living Cell
Authors: Elf Johan , Li Gene-Wei , Xie X. Sunney
Published: May 2007

Transcription factors regulate gene expression through their binding to DNA. In a living
Escherichia coli
cell, we directly observed specific binding of a
lac
repressor, labeled with a fluorescent protein, to a chromosomal
lac
operator. Using single-molecule detection techniques, we measured the kinetics of binding and dissociation of the repressor in response to metabolic signals. Furthermore, we characterized the nonspecific binding to DNA, one-dimensional (1D) diffusion along DNA segments, and 3D translocation among segments through cytoplasm at the single-molecule level. In searching for the operator, a
lac
repressor spends ∼90% of time nonspecifically bound to and diffusing along DNA with a residence time of <5 milliseconds. The methods and findings can be generalized to other nucleic acid binding proteins.
Drinking social norms and drinking behaviours: a multilevel analysis of 137 workgroups in 16 worksites
Authors: Barrientos-Gutierrez Tonatiuh , Gimeno David , Mangione Thomas W , Harrist Ronald B , Amick Benjamin C
Published: May 2007

Background:Previous studies on worksite drinking norms showed individually perceived norms were associated with drinking behaviours.

Objective:To examine whether restrictive drinking social norms shared by workgroup membership are associated with decreased heavy drinking, frequent drinking and drinking at work at the worker level.

Methods:The sample included 5338 workers with complete data nested in 137 supervisory workgroups from 16 American worksites. Multilevel models were fitted to examine the association between workgroup drinking norms and heavy drinking, frequent drinking and drinking at work.

Results:Multivariate adjusted models showed participants working in workgroups in the most discouraging drinking norms quartile were 45% less likely to be heavy drinkers, 54% less likely to be frequent drinkers and 69% less likely to drink at work than their counterparts in the most encouraging quartile.

Conclusions:Strong associations between workgroup level restrictive drinking social norms and drinking outcomes suggest public health efforts at reducing drinking and alcohol-related injuries, illnesses and diseases should target social interventions at worksites.
Body size and species richness along geographical gradients in Albertan diving beetle (Coleoptera: Dytiscidae) communities
Authors: Vamosi S.M. , Naydani C.J. , Vamosi J.C.
Published: May 2007

Species richness and body size often vary predictably along latitudinal and elevational gradients. Although these patterns have been well documented for a variety of taxa, the vast majority of studies have focused on terrestrial plants and animals. We used species lists of predaceous diving beetles (Coleoptera: Dytiscidae) collected from >400 lentic water bodies in southern Alberta to investigate the influences of latitude and elevation on species richness and body size. Because our data were based on species lists, we used proportion of, and probability of encountering at least one, large (i.e., mean body length >10 mm) diving beetle species as surrogates for the mean body size of diving beetles in a given water body. Species richness did not change with latitude and displayed a hump-shaped relationship with elevation, peaking at mid-elevations. High elevation (>2000 m) water bodies had markedly low species richness. Proportion of large species increased with latitude, although there was no effect on probability of occupancy by large species. Conversely, both measures tended to decrease with elevation, suggesting that large species are less prevalent at high elevations. We discuss potential factors contributing to the observed responses to latitude and elevation, with an emphasis on the potential impacts of oxygen limitation, productivity, and isolation at high elevation.
Do animals select habitat at small or large scales? An experiment with meadow voles (Microtus pennsylvanicus)
Authors: Oatway M.L. , Morris D.W.
Published: May 2007

Habitat and patch use are crucial to the dynamics of populations and the structure of ecological communities. But ecologists have not rigorously tested whether animals choose habitat at small or large scales. If individuals base their patch and habitat choices on fine-scale differences in habitat, then their use of different sites should correspond with measures of microhabitat at those sites. But if individuals use density to assess and respond to habitat at larger spatial scales, then site use should correspond with the scale of density-dependent habitat selection. We tested these predictions with experiments that measured microhabitat and monitored the use of capture sites by meadow voles ( Microtus pennsylvanicus Ord, 1815) in 0.25 ha old-field enclosures. We varied the density of voles in pairs of adjacent enclosures and tested for density-dependent habitat selection. Then we assessed whether their frequency of captures at trapping stations was best predicted at the small scale of microhabitat or at the much larger scale of enclosures where density varied. The voles selected habitat at different scales. When the use of enclosures was predicted by density, the scale of density-dependent choice trumped the use of small-scale patches. And when voles selected amongst different small-scale patches, their use of enclosures was independent of density. These results suggest that assessments of spatial scale in habitat use must include tests for both scale- and density-dependent habitat choice.
IMPEDANCE MEASUREMENTS ON A AND B SITE MODIFIED BISMUTH LAYERED STRUCTURE FERROELECTRIC CERAMICS
Authors: PRASAD N. V. , KARMAKAR S. , GUPTA S. M.
Published: May 2007

A and B site modified new bismuth layered structure ferroelectric ceramics of the Aurivillius family were prepared by the solid-state route. Impedance measurements were performed on these samples to understand the relaxation effects in the frequency range of 100 Hz to 1 MHz. From the detailed impedance and modulus spectroscopic analysis, it is found that the aliovalent modified B-site enhances the relaxor-like nature, compared to A-site substitution. These results were corroborated with ac-conductivity transport analysis. In this connection, a defect formula is also proposed. The results are discussed.
THERMAL EXPANSION STUDY OF A UVAROVITE RICH GARNET
Authors: PARTHASARTHY G. , SRINIVASAN R. , MUKHERJEE G. D. , BANSAL C. , CHATTERJEE ASHOK
Published: May 2007

Thermal expansion measurements have been performed on a uvarovite rich garnet sample for the first time and compared with the expansion data on grossular and pyrope-rich garnets reported in the literature. A semiclassical model has been used to analyze the data and to obtain various thermodynamic parameters. Using these parameters, the lattice specific heat and the corresponding entropy have also been calculated.
RARE-EARTH METAL SILICIDE NANOSTRUCTURES ON Si(001) SURFACE
Authors: DING TAO , SONG JUNQIANG , CAI QUN
Published: May 2007

Many rare-earth metals can react with Si atoms to form rare-earth metal silicides, which have a high conductivity and a low Schottky barrier on the n-type Si substrate. The investigations of the rare-earth metal silicide nanostructures self-assembled on the Si (001) surface are reviewed in this paper. The growth behaviors of Er silicide nanostructures are studied as the functions of annealing temperature, annealing time and Er coverage. The crystalline structures of the nanowires and nanoislands, the influence of substrate surface on the formation of nanostructures, and the shape transitions occuring during growth are analyzed comprehensively, which make contributions to the silicide nanostructure growth with the controlled structures and size-distributions. Furthermore, recent study progresses have been reported for the electrical and electronic properties of the rare-earth metal silicide nanowires.
Status of National Project for SOFC Development in Japan
Authors: Ujii Takashi
Published: May 2007

As for SOFC research and development, the elemental technology was started from 1989 in NEDO. From 2004, NEDO started system development of SOFC(Several 10- 100kW classes). In this 4years, we have two program of system development and development of basic technology for future SOFC. By 2007, we develop demonstration plant of Cogeneration system , several 10- 100kW class. And we develop prototype plant of SOFC-GT Combined Cycle system , 350kW class.  Additionally , we go ahead with development for future, low cost, high-durability and high-efficiency SOFC. This paper summarizes status of national project for SOFC Development in Japan