bluuebunny/crossref_metadata_2025 huggingface dataset:
Variability of interactions between barrel medic (Medicago truncatula) genotypes and Orobanche species
Authors: Fernández‐Aparicio M. , Pérez‐de‐Luque A. , Prats E. , Rubiales D.
Published: April 2008

A number of broomrapes (Orobanche spp.) are major threats for grain legumes in the Mediterranean area. Previous studies have shown very high levels of resistance to Orobanche crenata in Medicago truncatula with little variation among accessions hampering, therefore, its use for genetic analysis. In order to identify alternative systems for ulterior genetic and genomic analysis, we studied early stages of the interaction between M. truncatula accessions and a range of Orobanche species. We found significant differences in the induction of germination on Orobanche aegyptiaca, Orobanche foetida var. broteri, Orobanche minor, Orobanche nana and Orobanche ramosa seeds. Accessions also varied in the number of O. aegyptiaca, O. crenata, O. foetida var. broteri, O. nana and O. ramosa attachments supported. Applications of the synthetic germination stimulant GR24 increased the germination level of Orobanche cumana and O. minor. No attachments were observed for any of these species because of physical barriers typical of host resistance. On the contrary, increase of O. nana germination by GR24 led to an increase in number of attachments albeit the normal development of the nodules was stopped in a later stage. The genetic variation observed for induction of germination and subsequent attachment will be useful for isolating and characterising genes involved in early stages of Orobanche–host plant interaction and for the study of the biosynthetic pathways of production of germination stimulants.
Laser Therapy in Acute Stroke Treatment
Authors: Yip Samuel , Zivin Justin
Published: April 2008

Recent development of near infrared light therapy (NILT) as an acute stroke treatment is promising. In various preclinical animal stroke models, NILT has been shown to be effective in improving long-term stroke outcome. More importantly, NILT has a long postischemic therapeutic window that has not been previously observed in other treatment modalities. The preliminary efficacy and safety of NILT in acute stroke patients were demonstrated in the recently published phase II ***NeuroThera Effectiveness and Safety Trial (NEST-1). If confirmed by the NEST-II trial, ***NILT will revolutionize acute stroke management as ***ut has a long time window (possible 24 hr) for therapy. Moreover, understanding the mechanisms of action of NILT will provide a new therapeutic target for future drug or device development.
The effect of anticoagulant, storage temperature and dilution on cord blood hematology parameters over time
Authors: FREISE K. J. , SCHMIDT R. L. , GINGERICH E. L. , VENG‐PEDERSEN P. , WIDNESS J. A.
Published: April 2008

The objective of the study was to determine whether selected hematologic parameters measured on umbilical cord blood samples using an automated hematology analyzer (Sysmex XE‐2100) were affected by (i) anticoagulant (the specimens were collected in EDTA vs. sodium heparin), (ii) temperature (the specimens were maintained at 4° C vs. room temperature for up to 72 h) and (iii) 1 : 5 dilution vs. undiluted using the manufacturer’s diluting solution. Use of heparin, instead of EDTA, had little effect on the hematologic results (n = 8) except for lower platelet and progenitor cell counts. Results were remarkably stable for 72 h at either room temperature or 4° C except for modest red blood cell swelling at 24 h. Specimens of blood diluted at 1 : 5 had an immediate small, but significant change on white cell count (+13.3%), reticulocyte count (−11.2%) and reticulocyte hemoglobin content (−19.6%). Diluted samples did not change further over 4 h at room temperature. With a 1 : 5 dilution, analysis of 40 μl of cord blood stored for 3 days at room temperature may provide useful hematologic information with little phlebotomy loss.
Dissection Properties of the Human Aortic Media: An Experimental Study
Authors: Sommer Gerhard , Gasser T. Christian , Regitnig Peter , Auer Martin , Holzapfel Gerhard A.
Published: April 2008

Aortic dissection occurs frequently and is clinically challenging; the underlying mechanics remain unclear. The present study investigates the dissection properties of the media of 15 human abdominal aortas (AAs) by means of direct tension tests (n=8) and peeling tests (n=12). The direct tension test demonstrates the strength of the media in the radial direction, while the peeling test allows a steady-state investigation of the dissection propagation. To explore the development of irreversible microscopic changes during medial dissection, histological images (n=8) from four AAs at different peeling stages are prepared and analyzed. Direct tension tests of coin-shaped medial specimens result in a radial failure stress of 140.1±15.9kPa (mean±SD, n=8). Peeling tests of rectangular-shaped medial strips along the circumferential and axial directions provide peeling force∕width ratios of 22.9±2.9mN∕mm(n=5) and 34.8±15.5mN∕mm(n=7); the related dissection energies per reference area are 5.1±0.6mJ∕cm2 and 7.6±2.7mJ∕cm2, respectively. Although student’s t-tests indicate that force∕width values of both experimental tests are not significantly different (α=0.05, p=0.125), the strikingly higher resisting force∕width obtained for the axial peeling tests is perhaps indicative of anisotropic dissection properties of the human aortic media. Peeling in the axial direction of the aorta generates a remarkably “rougher” dissection surface with respect to the surface generated by peeling in the circumferential direction. Histological analysis of the stressed specimens reveals that tissue damage spreads over approximately six to seven elastic laminae, which is about 15–18% of the thickness of the abdominal aortic media, which forms a pronounced cohesive zone at the dissection front.
Paraspinal Muscle Vibration Alters Dynamic Motion of the Trunk
Authors: Arashanapalli M. , Wilson S. E.
Published: April 2008

Loss in dynamic stability of the low back has been identified as a potential factor in the etiology of low back injuries. A number of factors are important in the ability of a person to maintain an upright trunk posture including the preparatory stiffness of the trunk and the magnitude and timing of the neuromotor response. A neuromotor response requires appropriate sensing of joint motion. In this research, the role of this sensory ability in dynamic performance of the trunk was examined using a simple pendulum model of the trunk with neuromotor feedback. An increased sensory threshold was found to lead to increased torso flexion and increased delay in neuromotor response. This was confirmed experimentally using paraspinal muscle vibration which is known to alter proprioception of the muscle spindle organs. Before, during and after exposure to bilateral, paraspinal muscle vibration for 20minutes, the dynamic response of subjects to an unexpected torso flexion load was examined. Subjects were found to have a 19.5% slower time to peak muscle activity and a 16.1% greater torso flexion during exposure to paraspinal muscle vibration. Torso flexion remained significantly increased after vibration exposure relative to before exposure. These results suggest that the neuromotor response plays an important role in trunk dynamics. Loss in sensitivity of the sensory system can have a detrimental effect on trunk dynamics, increasing delays in neuromotor response and increasing the motion of the trunk in response to an unexpected load.
Mechanical Stresses in Abdominal Aortic Aneurysms: Influence of Diameter, Asymmetry, and Material Anisotropy
Authors: Rodríguez José F. , Ruiz Cristina , Doblaré Manuel , Holzapfel Gerhard A.
Published: April 2008

Biomechanical studies suggest that one determinant of abdominal aortic aneurysm (AAA) rupture is related to the stress in the wall. In this regard, a reliable and accurate stress analysis of an in vivo AAA requires a suitable 3D constitutive model. To date, stress analysis conducted on AAA is mainly driven by isotropic tissue models. However, recent biaxial tensile tests performed on AAA tissue samples demonstrate the anisotropic nature of this tissue. The purpose of this work is to study the influence of geometry and material anisotropy on the magnitude and distribution of the peak wall stress in AAAs. Three-dimensional computer models of symmetric and asymmetric AAAs were generated in which the maximum diameter and length of the aneurysm were individually controlled. A five parameter exponential type structural strain-energy function was used to model the anisotropic behavior of the AAA tissue. The anisotropy is determined by the orientation of the collagen fibers (one parameter of the model). The results suggest that shorter aneurysms are more critical when asymmetries are present. They show a strong influence of the material anisotropy on the magnitude and distribution of the peak stress. Results confirm that the relative aneurysm length and the degree of aneurysmal asymmetry should be considered in a rupture risk decision criterion for AAAs.
Design and Calibration of Load Sensing Orthopaedic Implants
Authors: Bergmann G. , Graichen F. , Rohlmann A. , Westerhoff P. , Heinlein B. , Bender A. , Ehrig R.
Published: April 2008

Contact forces and moments act on orthopaedic implants such as joint replacements. The three forces and three moment components can be measured by six internal strain gauges and wireless telemetric data transmission. The accuracy of instrumented implants is restricted by their small size, varying modes of load transfer, and the accuracy of calibration. Aims of this study were to test with finite element studies design features to improve the accuracy, to develop simple but accurate calibration arrangements, and to select the best mathematical method for calculating the calibration constants. Several instrumented implants, and commercial and test transducers were calibrated using different loading setups and mathematical methods. It was found that the arrangement of flexible elements such as bellows or notches between the areas of load transfer and the central sensor locations is most effective to improve the accuracy. Increasing the rigidity of the implant areas, which are fixed in bones or articulate against joint surfaces, is less effective. Simple but accurate calibration of the six force and moment components can be achieved by applying eccentric forces instead of central forces and pure moments. Three different methods for calculating the measuring constants proved to be equally well suited. Employing these improvements makes it possible to keep the average measuring errors of many instrumented implants below 1–2% of the calibration ranges, including cross talk. Additional errors caused by noise of the transmitted signals can be reduced by filtering if this is permitted by the sampling rate and the required frequency content of the loads.
Numerical Simulation of Pre- and Postsurgical Flow in a Giant Basilar Aneurysm
Authors: Rayz Vitaliy L. , Lawton Michael T. , Martin Alastair J. , Young William L. , Saloner David
Published: April 2008

Computational modeling of the flow in cerebral aneurysms is an evolving technique that may play an important role in surgical planning. In this study, we simulated the flow in a giant basilar aneurysm before and after surgical takedown of one vertebral artery. Patient-specific geometry and flowrates obtained from magnetic resonance (MR) angiography and velocimetry were used to simulate the flow prior to and after the surgery. Numerical solutions for steady and pulsatile flows were obtained. Highly three-dimensional flows, with strong secondary flows, were computed in the aneurysm in the presurgical and postsurgical conditions. The computational results predicted that occlusion of a vertebral artery would result in a significant increase of the slow flow region formed in the bulge of the aneurysm, where increased particle residence time and velocities lower than 2.5cm∕s were computed. The region of slow flow was found to have filled with thrombus following surgery. Predictions of numerical simulation methods are consistent with the observed outcome following surgical treatment of an aneurysm. The study demonstrates that computational models may provide hypotheses to test in future studies, and might offer guidance for the interventional treatment of cerebral aneurysms.
Effect of Blood Flow on Near-the-Wall Mass Transport of Drugs and Other Bioactive Agents: A Simple Formula to Estimate Boundary Layer Concentrations
Authors: Rugonyi Sandra
Published: April 2008

Transport of bioactive agents through the blood is essential for cardiovascular regulatory processes and drug delivery. Bioactive agents and other solutes infused into the blood through the wall of a blood vessel or released into the blood from an area in the vessel wall spread downstream of the infusion/release region and form a thin boundary layer in which solute concentration is higher than in the rest of the blood. Bioactive agents distributed along the vessel wall affect endothelial cells and regulate biological processes, such as thrombus formation, atherogenesis, and vascular remodeling. To calculate the concentration of solutes in the boundary layer, researchers have generally used numerical simulations. However, to investigate the effect of blood flow, infusion rate, and vessel geometry on the concentration of different solutes, many simulations are needed, leading to a time-consuming effort. In this paper, a relatively simple formula to quantify concentrations in a tube downstream of an infusion/release region is presented. Given known blood-flow rates, tube radius, solute diffusivity, and the length of the infusion region, this formula can be used to quickly estimate solute concentrations when infusion rates are known or to estimate infusion rates when solute concentrations at a point downstream of the infusion region are known. The developed formula is based on boundary layer theory and physical principles. The formula is an approximate solution of the advection-diffusion equations in the boundary layer region when solute concentration is small (dilute solution), infusion rate is modeled as a mass flux, and there is no transport of solute through the wall or chemical reactions downstream of the infusion region. Wall concentrations calculated using the formula developed in this paper were compared to the results from finite element models. Agreement between the results was within 10%. The developed formula could be used in experimental procedures to evaluate drug efficacy, in the design of drug-eluting stents, and to calculate rates of release of bioactive substances at active surfaces using downstream concentration measurements. In addition to being simple and fast to use, the formula gives accurate quantifications of concentrations and infusion rates under steady-state and oscillatory flow conditions, and therefore can be used to estimate boundary layer concentrations under physiological conditions.
Development of a Testing Methodology to Quantify Bone Load Transfer Patterns for Multiple Stemmed Implants in a Single Bone With an Application in the Distal Ulna
Authors: Austman Rebecca L. , Quenneville Cheryl E. , Beaton Brendon J. B. , King Graham J. W. , Gordon Karen D. , Dunning Cynthia E.
Published: April 2008

Optimal parameters for many orthopaedic implants, such as stem length and material, are unknown. Geometry and mechanical properties of bone can vary greatly amongst cadaveric specimens, requiring a large number of specimens to test design variations. This study aimed to develop an experimental methodology to measure bone strains as a function of multiple implant stem designs in a single specimen, and evaluate its efficacy in the distal ulna. Eight fresh-frozen cadaveric ulnae were each instrumented with 12 uniaxial strain gauges on the medial and lateral surfaces of the bone. The proximal portion of each ulna was cemented in a custom-designed jig that allowed a medially directed force to be applied to the distal articular surface. An implant with a finely threaded stem was cemented into the canal by an experienced upper extremity orthopaedic surgeon. Six loads (5–30N) were applied sequentially to the lateral surface of the prosthetic head using a materials testing machine. Testing was repeated after breaking the stem-cement bond, and after removing and reinserting the stem several times into the threaded cement mantle. Near the end of the testing period, the initial stem was reinserted and data were collected to determine if there was any change in bone properties or testing setup over time. Finally, a smooth stem was inserted for comparison to the threaded stem. Strain varied linearly with load (R2≥0.99) for all testing scenarios. Bending strains were not affected by breaking the stem-cement bond (P=0.7), testing durations up to 18h(P=0.7), nor the presence of threads when compared to a smooth stem (P>0.4). Furthermore, for all gauges, there was no interaction between the effect of the threads and level of applied load (P>0.1). This methodology should prove to be useful to compare stem designs of varying lengths and materials in the same bone, allowing for a direct comparison between implant designs for the ulna and other bones subjected primarily to bending loads. Furthermore, it will minimize the need for large numbers of specimens to test multiple implant designs. The ultimate goal of using this protocol is to optimize implant stem properties, such as length and material, with respect to load transfer.
The Phan-Thien and Tanner Model Applied to Thin Film Spherical Coordinates: Applications for Lubrication of Hip Joint Replacement
Authors: Tichy John , Bou-Saïd Benyebka
Published: April 2008

The Phan-Thien and Tanner (PTT) model is one of the most widely used rheological models. It can properly describe the common characteristics of viscoelastic non-Newtonian fluids. There is evidence that synovial fluid in human joints, which also lubricates artificial joints, is viscoelastic. Modeling the geometry of the total hip replacement, the PTT model is applied in spherical coordinates for a thin confined fluid film. A modified Reynolds equation is developed for this geometry. Several simplified illustrative problems are solved. The effect of the edge boundary condition on load-carrying normal stress is discussed. Solutions are also obtained for a simple squeezing flow. The effect of both the relaxation time and the PTT shear parameter is to reduce the load relative to a Newtonian fluid with the same viscosity. This implies that the Newtonian model is not conservative and may overpredict the load capacity. The PTT theory is a good candidate model to use for joint replacement lubrication. It is well regarded and derivable from molecular considerations. The most important non-Newtonian characteristics can be described with only three primary material parameters.
Modeling the Thermal Responses of the Skin Surface During Hand-Object Interactions
Authors: Ho Hsin-Ni , Jones Lynette A.
Published: April 2008

The objective of this research is to analyze and model the decreases in skin temperature when the hand makes contact with an object at room temperature so that thermal feedback can be incorporated into haptic displays. A thermal model is proposed that predicts the thermal responses of the skin and object surface as well as the heat flux exchanged during hand-object interactions. The model was evaluated by comparing the theoretical predictions of temperature changes to those experimentally measured using an infrared thermal measurement system. The thermal measurement system was designed to overcome the limitations imposed by contact thermal sensors, and was able to measure skin temperature during contact, together with the contact area and contact force. The experimental results indicated that over the pressure range of 0.73–10.98kPa, changes in skin temperature were well localized to the contact area and were affected by contact pressure. The pressure in turn influenced both thermal contact resistance and blood flow. Over the range of contact forces typically used in manual exploration, blood perfusion and metabolic heat generation do not appear to have a significant effect on the skin’s thermal responses. The theoretical predictions and the measured data were consistent in characterizing the time course and amplitude of the skin temperature change during contact with differences typically being less than 1°C between the two for pressures greater than 4kPa. These findings indicate that the proposed thermal model is able to characterize and predict the skin temperature responses during hand-object interactions and could be used in a thermal display that simulates the properties of different materials.
Carousel Effect in Alveolar Models
Authors: Laine-Pearson F. E. , Hydon P. E.
Published: April 2008

Experimental work over the past decade has shown that recirculation in alveoli substantially increases the transport of particles. We have previously shown that, for nondiffusing passive particles, this can be understood with the aid of Moffatt’s famous corner flow model. Without wall motion, passive particles recirculate in a regular fashion and no chaos exists; however, wall motion produces extensive chaotic flow. Aerosols typically do not follow this flow as they are fundamentally different from fluid particles. Here, we construct a simple model to study diffusing particles in the presence of recirculation. We assume that all particles are passive, that is to say that they do not significantly alter the underlying flow. In particular, we consider particles with high Péclet number and neglect inertial effects. We modify the Lagrangian system for corner eddies to accommodate diffusing particles. Particle transport is governed by Langevin equations. Ensembles of diffusing particles are tracked by numerical integration. We show that transport of diffusing particles is enhanced by sufficiently strong underlying recirculation through a mechanism that we call the “carousel effect.” However, as the corner is approached, the recirculation rapidly decreases in intensity, favoring motion by diffusion. Far from the corner’s apex, recirculation dominates. For real alveoli, the model indicates that sufficiently strong recirculation can enhance transport of diffusing particles through the carousel effect.
In Vitro Fatigue Failure of Cemented Acetabular Replacements: A Hip Simulator Study
Authors: Zant N. P. , Heaton-Adegbile P. , Hussell J. G. , Tong J.
Published: April 2008

Although hip simulators for in vitro wear testing of prosthetic materials used in total hip arthroplasty (THA) have been available for a number of years, similar equipment has yet to appear for endurance testing of fixation in cemented THA, despite considerable evidence of late aseptic loosening as one of the most significant failure mechanisms in this type of replacements. An in vitro study of fatigue behavior in cemented acetabular replacements has been carried out, utilizing a newly developed hip simulator. The machine was designed to simulate the direction and the magnitude of the hip contact force under typical physiological loading conditions, including normal walking and stair climbing, as reported by Bergmann et al. (2001, Hip 98, Freie Universitaet, Berlin). A 3D finite element analysis has been carried out to validate the function of the hip simulator and to evaluate the effects of boundary conditions and geometry of the specimen on the stress distribution in the cement mantle. Bovine pelvic bones were implanted with a Charnley cup, using standard manual cementing techniques. Experiments were carried out under normal walking and descending stairs loading conditions with selected load levels from a body weight of 75–125kg. Periodically, the samples were removed from the test rigs to allow CT scanning for the purpose of monitoring damage development in the cement fixation. The hip simulator was found to be satisfactory in reproducing the hip contact force during normal walking and stair climbing, as reported by Bergmann et al. Finite element analysis shows that the stress distributions in the cement mantle and at the bone-cement interface are largely unaffected by the geometry and the boundary conditions of the model. Three samples were tested up to 17×106cycles and sectioned post-testing for microscopic studies. Debonding at the bone-cement interface of various degrees in the posterior-superior quadrant was revealed in these samples, and the location of the failures corresponds to the highest stressed region from the finite-element analysis. Preliminary experimental results from a newly developed hip simulator seem to suggest that debonding at the bone-cement interface is the main failure mechanism in cemented acetabular replacements, and descending stairs seem to be more detrimental than normal walking or ascending stairs with regard to fatigue integrity of cement fixation.
Performance and Emissions of a Diesel Engine Using a Coal-Derived Fuel
Authors: Litzinger T. A. , Buzza T. G.
Published: April 2008

A coal-derived synthetic fuel was blended with a control diesel fuel and then tested in a single-cylinder, direct-injected, diesel engine. Comparisons of the blended fuel to the control Diesel fuel were made on the basis of performance, combustion characteristics, gas-phase emissions, including aldehydes, and particulate emissions. In addition, the mutagenic activity of the soluble organic compounds from the particulates were analyzed using the Ames test. The objective of these experiments was to determine how well the fuel blend would perform as a direct replacement for diesel fuel. Use of the blended fuel decreased performance and increased gas phase emissions, but particulate emissions were unchanged. However, a significant increase in the mutagenic effect of the soluble organic compounds was observed with the blended fuel.
Second Law Analysis of Spray Evaporation
Authors: Som S. K. , Mitra A. K. , Sengupta S. P.
Published: April 2008

A second law analysis has been developed for an evaporative atomized spray in a uniform parallel stream of hot gas. Using a discrete droplet evaporation model, an equation for entropy balance of a drop has been formulated to determine numerically the entropy generation histories of the evaporative spray. For the exergy analysis of the process, the rate of heat transfer and that of associated irreversibilities for complete evaporation of the spray have been calculated. A second law efficiency (ηII), defined as the ratio of the total exergy transferred to the sum of the total exergy transferred and exergy destroyed, is finally evaluated for various values of pertinent input parameters, namely, the initial Reynolds number (Rei = 2ρgVixi/μg) and the ratio of ambient to initial drop temperature (Θ∞′/Θi′).
Elastic-Plastic Compaction of Geopressured Sandstone
Authors: Fahrenthold E. P.
Published: April 2008

The economic development of United States Gulf Coast geopressured-geothermal energy resources depends in part upon an improved understanding of reservoir rock response to long-term aquifer production. Although field experiments have shown that rock mechanical response can significantly influence well production rates and that sand production problems can prevent efficient reservoir depletion, the absence of general reservoir rock models has hindered analytical studies of such problems. This paper provides experimental property measurements and a three-dimensional elastic-plastic constitutive model for sandstone cored from the most active Gulf Coast geopressured well currently in operation.
Deflections and Stresses of Antisymmetric Angle-Ply Clamped Plates Under Transverse Loading
Authors: Yahyavi A. H. , Chandrashekhara K.
Published: April 2008

Closed-form solutions are not tractable for clamped composite plates due to the boundary conditions and anisotropy of the plate. In the present work, a method based on Lagrange multipliers is developed for the bending analysis of antisymmetric angle-ply clamped plates. The transverse shear flexibility is incorporated in the energy functional. Boundary conditions not satisfied by the assumed series are enforced using Lagrange multipliers. Results are presented to study the influence of shear deformation, anisotropy, aspect ratio and loadings on the deflections and stresses of clamped plates.
Testing and Modeling of Oilfield Valves in Extreme Temperature Situations
Authors: Guice W. L. , Hoang L. G.
Published: April 2008

Valves for use in oilfield applications have been tested in free convective water environments with hot internal flows. Two-dimensional finite element modeling was shown to give accurate reproduction of the test results. A dimensionless temperature differential ratio was shown to give accurate prediction of the internal temperature of any point within the valve. This dimensionless ratio permits results of testing in a single thermal environment to be extended to a wide range of possible temperature conditions.
Engineering Functional Analysis—Part II
Authors: Evans R. B. , von Spakovsky M. R.
Published: April 2008

In this paper, a new formalism called Engineering Functional Analysis (EFA) is presented. This formalism results in higher degrees of decentralization for engineering system optimization than is otherwise possible. By decentralization, it is meant that the improvement or optimization of individual components by themselves (i.e., components which are isolated economically from the rest of the overall system) serves to improve or optimize the system as a whole (within some degree of error, which defines the degree of decentralization). Higher degrees of decentralization are important in that they provide a more stable economic environment for individual components, thus permitting more rapid synthesis and greater system improvement than could otherwise be obtained.
A Leak Localization Method of Pipeline by Means of Fluid Transient
Model
Authors: Kiuchi T.
Published: April 2008

This paper describes a method for estimating the position of a detected leak by applying a fluid transient model to a real-time pipeline system. The method takes into account flow rate and pressure profiles along a pipeline in a transient condition based on an assumption of quasi-steady-state flow. The result of case studies using a hypothetical gas pipeline system shows that, even in a transient condition, the method gives a more accurate estimation of a leak position than conventional methods which do not consider flow rate or pressure profiles along a pipeline. The method is also applicable to a pipeline having consumer stations which cause abrupt changes of flow rate profile along the pipeline. Furthermore, the influence of instrument accuracy on the result of the method is examined. The result also shows the advantage of the method compared to the conventional methods.
Effects of Nozzle Orientation on the Structure and Emissions of Spray
Flames
Authors: Madanahalli A. V. , Gollahalli S. R.
Published: April 2008

An experimental study of the effects of the orientation of the liquid fuel stream relative to the air stream from a twin fluid atomizer located in an open-jet wind tunnel is presented. The orientation angle was set at 0 (concurrent), 45, 90, 135, and 180 deg (directly opposed). At 45 and 90 deg, the flame length, the radiation emission, and the concentrations of carbon monoxide, carbon dioxide, nitric oxide, and soot are higher than those at co-flow conditions. At 135 deg, all these quantities decrease markedly from their values at 90 deg and again increase when the fuel and air streams are directly opposed (180 deg). These changes are discussed in terms of the influx of air and recirculation of combustion products into the salient zones of the flame.
High-Power TSP Bits
Authors: Cohen J. H. , Maurer W. C. , Westcott P. A.
Published: April 2008

This paper reviews a three-year R&D project to develop advanced TSP bits that can operate at power levels 5 to 10 times greater than those typically delivered by rotary rigs. These bits are designed to operate on advanced drilling motors that drill 3 to 6 times faster than rotary rigs. TSP bit design parameters that were varied during these tests include cutter size, shape, density, and orientation. Drilling tests conducted in limestone, sandstone, marble, and granite blocks showed that these optimized bits drilled many of these rocks at 500 to 1000 ft/hr (150 to 300 m/h), compared to 50 to 100 ft/hr (15 to 30 m/h) for roller bits. These tests demonstrated that TSP bits are capable of operating at the high speeds and high torques delivered by advanced drilling motors now being developed. These advanced bits and motors are designed for use in slim-hole and horizontal drilling applications.
Divergence of Quaternary Structures Among Bacterial Flagellar Filaments
Authors: Galkin Vitold E. , Yu Xiong , Bielnicki Jakub , Heuser John , Ewing Cheryl P. , Guerry Patricia , Egelman Edward H.
Published: April 2008

It has been widely assumed that the atomic structure of the flagellar filament from
Salmonella typhimurium
serves as a model for all bacterial flagellar filaments given the sequence conservation in the coiled-coil regions responsible for polymerization. On the basis of electron microscopic images, we show that the flagellar filaments from
Campylobacter jejuni
have seven protofilaments rather than the 11 in
S. typhimurium
. The vertebrate Toll-like receptor 5 (TLR5) recognizes a region of bacterial flagellin that is involved in subunit-subunit assembly in
Salmonella
and many other pathogenic bacteria, and this short region has diverged in
Campylobacter
and related bacteria, such as
Helicobacter pylori
, which are not recognized by TLR5. The driving force in the change of quaternary structure between
Salmonella
and
Campylobacter
may have been the evasion of TLR5.
Changes in Tetracycline Susceptibility of Enteric Bacteria following Switching to Nonmedicated Milk Replacer for Dairy Calves
Authors: Kaneene John B. , Warnick Lorin D. , Bolin Carole A. , Erskine Ronald J. , May Katherine , Miller RoseAnn
Published: April 2008

A randomized intervention study was conducted to determine if discontinuing use of calf milk replacer medicated with oxytetracycline results in increased tetracycline susceptibility in
Salmonella
and
Campylobacter
spp. and
Escherichia coli
in dairy calves over a 12-month period. Dairy herds with enteric bacteria with known low tetracycline susceptibility were enrolled for the study. Fecal samples from preweaned calves and environmental samples were collected from eight dairy herds in Michigan and New York State. Samples were collected monthly for 3 months prior to and 12 months after four of the eight herds discontinued medicated milk replacer feeding.
Salmonella
and
Campylobacter
spp. and
E. coli
were isolated, and antimicrobial susceptibility testing was conducted using automated broth microdilution. A total of 804 intervention and 1,026 control calf fecal samples and 122 intervention and 136 control environmental samples were collected for testing. No differences in owner-reported morbidity and mortality between treatment groups were seen. The intervention was significantly associated with increasing tetracycline susceptibility in
E. coli
and
Salmonella
. Tetracycline susceptibility increased in intervention herds for the first 3 months after switching to nonmedicated milk replacer but declined in subsequent months. Discontinuing the practice of feeding medicated milk replacers to calves increased tetracycline susceptibility in
E. coli
and
Salmonella
on dairy farms, without increasing cattle disease, but declines in effectiveness after 3 months suggest that other factors contribute to decreasing susceptibility on the farm.
Human Parainfluenza Virus Type 2 V Protein Inhibits Genome Replication by Binding to the L Protein: Possible Role in Promoting Viral Fitness
Authors: Nishio Machiko , Ohtsuka Junpei , Tsurudome Masato , Nosaka Tetsuya , Kolakofsky Daniel
Published: April 2008

The human parainfluenza virus type 2 (hPIV2) V protein plays important roles in inhibiting the host interferon response and promoting virus growth, but its role in hPIV2 replication and transcription is not clear. A green fluorescent protein (GFP)-expressing a negative-sense minigenomic construct of hPIV2 has been established by standard technology, with helper plasmids expressing the nucleocapsid protein (NP), phosphoprotein (P), and large RNA polymerase (L) protein, to examine the role of V protein. We found that the simultaneous expression of wild-type V protein in the minigenome system inhibited GFP expression, at least in part, by inhibiting minigenome replication. In contrast, expression of C terminally truncated or mutant hPIV2 V proteins had no effect. Moreover, the V protein of simian virus 41, the rubulavirus most closely related virus to hPIV2, also inhibited GFP expression, whereas that of PIV5, a more distantly related rubulavirus, did not. Using these other rubulavirus V proteins, as well as various mutant hPIV2 V proteins, we found that the ability of V protein to inhibit GFP expression correlated with its ability to bind to L protein via its C-terminal V protein-specific region, but there was no correlation with NP binding. A possible role for this inhibition of genome replication in promoting viral fitness is discussed.
Dose-response relationship between physical activity and mental health: the Scottish Health Survey
Authors: Hamer M , Stamatakis E , Steptoe A
Published: April 2008

Objectives:

Regular physical activity is thought to be associated with better mental health, although there is a lack of consensus regarding the optimal amount and type of activity to achieve these benefits. The association between mental health and physical activity behaviours was examined among a representative sample of men and women from the Scottish Health Surveys.

Methods:

Self-reported physical activity was measured and the General Health Questionnaire (GHQ-12) was administered in order to obtain information on current mental health. Participants were 19 842 men and women. Risk estimates per category of physical activity sessions per week were calculated using logistic regression models.

Results:

Psychological distress (based on a score of 4 or more on the GHQ-12) was evident in 3200 participants. Any form of daily physical activity was associated with a lower risk of psychological distress after adjustment for age, gender, social economic group, marital status, body mass index, long-standing illness, smoking and survey year (OR 0.59, 95% CI 0.52 to 0.66, p<0.001). A dose-response relationship was apparent, with moderate reductions in psychological distress with less frequent activity (OR 0.67, 95% CI 0.61 to 0.75). Different types of activities including domestic (housework and gardening), walking and sports were all independently associated with lower odds of psychological distress, although the strongest effects were observed for sports (OR 0.67, 95% CI 0.54 to 0.82).

Conclusion:

Mental health benefits were observed at a minimal level of at least 20 min/week of any physical activity, although a dose-response pattern was demonstrated with greater risk reduction for activity at a higher volume and/or intensity.
QUALITATIVE STUDIES OF SOIL MICROORGANISMS: XI. FURTHER OBSERVATIONS ON THE NUTRITIONAL CLASSIFICATION OF BACTERIA
Authors: Stevenson I. L. , Rouatt J. W.
Published: April 2008

A review of the method developed in this laboratory in 1943 for the nutritional classification of soil bacteria has suggested slight amendments in certain differential media: (1) the substitution of vitamin-free casamino acids for a combination of amino acids, and (2) the addition of vitamin B12 to the growth factor media. In a comparative study with a newly proposed scheme of classification, the more selective plating medium advocated was found to be less suitable for the isolation of soil bacteria than the nonselective soil extract agar in the original method. Furthermore, the replacement of potassium nitrate with diammonium phosphate as source of inorganic nitrogen in the basal medium failed to cause any significant change in the nutritional grouping. Results from the nutritional classification of some 600 isolates by the two methods showed that the new procedure represents only a slight modification of the original system.
A regression mixture with logistic weights for modeling heterogeneous crustacean growth data when the maturity phase is unknown
Authors: Surette Tobie , Allard Jacques
Published: April 2008

Piecewise linear models (PLMs) have been used widely in crustacean morphometry and growth modeling when subjects belong to more than one undetermined maturity stage, for example, to model immature and adolescent male snow crab (Chionoecetes opilio) growth increment at moulting as a function of pre-moult size. PLMs assume, unrealistically, that the transition between the maturity stages occurs at a fixed size. PLMs have also often been applied without taking into account the heterogeneity of variance or without supplying parameter confidence intervals. We propose to describe the unknown maturity stage and the known growth increments as functions of the pre-moult size by regression mixture with logistic weights (RMLW), where a logistic function and two linear regressions are mixed with weights provided by the logistic function. Errors are assumed to be normally distributed with a standard deviation depending linearly on the expected growth increment. Parameters and their confidence intervals are obtained using maximum likelihood. Model diagnostic procedures and a posteriori maturity stage classification methods are presented. The methodology is applied to 1311 snow crab growth observations, and results are compared with those of other snow crab studies. The methodology has widespread applications to crustacean morphometry and can be generalized to nonlinear relationships.
Genetic relationships among fruiting-mei (Prunus mume Sieb. et Zucc.) cultivars evaluated with AFLP and SNP markers
Authors: Fang Jinggui , Twito Tal , Zhang Zhen , Chao ChihCheng T.
Published: April 2008

Genetic relationships among 50 fruiting-mei (Prunus mume Sieb. et Zucc.) cultivars from China and Japan were investigated, using 767 amplified fragment length polymorphism (AFLP) and 103 single nucleotide polymorphism (SNP) markers. The polymorphism among the cultivars was found to be 69.77%, based on EcoR I + Mse I AFLP primer pairs. The sequence alignment of 11 group sequences, derived from 50 samples, yielded 103 SNPs; the total length of genomic sequences was 3683 bp. Among these SNPs, 73 were heterozygous in the loci of different cultivars. The SNP distribution was 58% transition, 40% transversion, and 2% InDels. There was also 1 trinucleotide deletion. AFLP and SNP markers allowed us to evaluate the genetic diversity of these 50 fruiting-mei cultivars. The 2 derived cladograms did display some differences: all cultivars formed 2 subclusters (1A and 1B) in the cladogram based on AFLP polymorphisms, and formed 3 subclusters (2A, 2B, and 2C) in the cladogram based on SNP polymorphisms; and, in the cladogram based on AFLP polymorphisms, most cultivars from the Guangdong to Fujian provinces (G–F) in China, from the Yunnan, Hunan, and Sichuan provinces (Y–S–H) in China, and from Japan grouped in cluster 1A, and 18 (78.26%) of 23 cultivars from Jiangsu to Zhejiang provinces in China (J–Z) grouped in cluster 1B. The results demonstrate that mei cultivars from Japan are clustered with cultivars from China, and support the hypothesis that mei in Japan were introduced from China. Cultivars from the J–Z region of China have more genetic similarities. Cultivars from the G–F and Y–S–H regions have fewer genetic similarities and suggest more germplasm exchanges in the past.
Triarylmethyl chlorides as novel, efficient, and mild organic catalysts for the synthesis of N-sulfonyl imines under neutral conditions
Authors: Khalafi-Nezhad Ali , Parhami Abolfath , Zare Abdolkarim , Shirazi Amir Nasrolahi , Zare Ahmad Reza Moosavi , Hassaninejad Alireza
Published: April 2008

A highly efficient procedure for the preparation of N-sulfonyl imines via condensation of sulfonamides with aldehydes as well as ketones in the presence of triarylmethyl chlorides as metal-free organo-catalysts at 40 °C is described. The advantages of this class of catalysts over the reported ones are their efficiency and possibility of running reactions in neutral media that makes them suitable for acid-sensitive substrates.Key words: triarylmethyl chloride, N-sulfonyl imine, sulfonamide, aldehyde, ketone.
Purification and properties of NAD(P)-independent polyol dehydrogenase complex from the plasma membrane ofGluconobacter oxydans
Authors: VanLare Ian J. , Claus G.W.
Published: April 2008

Gluconobacter oxydans rapidly oxidizes many different polyhydroxy alcohols (polyols). Polyol oxidations are catalyzed by constitutively synthesized membrane-bound dehydrogenases directly linked to the electron transport chain. A polyol-oxidizing enzyme was isolated from the membranes of G. oxydans and tested for its ability to oxidize various substrates. The enzyme was composed of three subunits: a 67 kDa catalytic unit, a 46 kDa c-type cytochrome, and a 15 kDa subunit. The enzyme oxidized compounds containing three or more hydroxyl groups but did not oxidize mono-, di-, or cyclic alcohols; aldehydes; carboxylic acids; or mono- or di-saccharides. Therefore, we propose this enzyme be considered a polyol dehydrogenase.
Increases in microbial nitrogen production and efficiency in vitro with three inhibitors of ruminal methanogenesis
Authors: Ungerfeld E.M. , Rust S.R. , Burnett R.
Published: April 2008

It was hypothesized that the addition of crotonic acid or 3-butenoic acid would relieve constraints in digestibility observed when methane formation is inhibited by lumazine, propynoic acid, or ethyl 2-butynoate. In six incubations, one of the three methanogenesis inhibitors, at three different concentrations, was combined with either crotonic acid or 3-butenoic acid at two different concentrations. A mixture of buffer and ruminal fluid (4:1) was incubated with grass hay in Erlenmeyer flasks for 72 h. Initial concentrations were 0, 0.6, and 1.2 mmol/L for lumazine; 0, 2, and 4 mmol/L for propynoic acid; and 0, 4, and 8 mmol/L for ethyl 2-butynoate. 15Nitrogen (N) incorporation was used as a microbial marker. All three methanogenesis inhibitors decreased proteolysis. Propynoic acid and ethyl 2-butynoate at 8 mmol/L also decreased the digestibility of organic matter and neutral detergent fibre. However, all three inhibitors of methanogenesis increased the production of microbial N through an improvement of synthetic efficiency. Crotonic acid and 3-butenoic acid were generally ineffective in compensating digestibility decreases caused by the inhibitors of methanogenesis. It is of interest to elucidate the mechanisms by which these compounds increased the efficiency of microbial N production. Lumazine and the addition of low levels of ethyl 2-butynoate could potentially benefit animal production by lowering methane emissions, decreasing ruminal proteolysis, and increasing microbial N production without affecting organic matter digestibility.