bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD Numerical Simulation of the Submarine Pipeline With a Spoiler
Authors: Zhao Jianping , Wang Xuechao
Published: June 2009

Submarine pipeline is one of the most important oil transportation components; pipeline failure due to overspan is the most serious failure mechanism. There are four reasons of pipeline span formation, including erosion of seabed, bumpy seabed, submarine pipeline climbing slope, and pipeline ascending to offshore platform. The Hangzhou Bay submarine pipeline is the most important subproject of the Yong-Hu-Ning network, and it is also the biggest long-distance pipeline for crude oil in China. Due to the dynamic nature of Hangzhou Bay, including high tides and high current amplified by the shallow waters, a self-burial method was selected as the best solution. By increasing the velocity of the stream between the pipeline and the seabed, shear stress on the seabed was enhanced. This localized increase in shear stress causes the seabed under the pipe to erode more quickly and facilitates self-burial of the pipe. To facilitate self-burial, a nonmetallic vertical fin is fastened to the top of the pipeline. In this paper flow around a pipeline with and without a spoiler near a smooth wall is simulated with FLUENT version 6.1. It is found that the velocity affected the shear stress, and the height of the spoiler does not have an obvious effect on the shear stress.
First Order Stochastic Lagrange Model for Asymmetric Ocean Waves
Authors: Lindgren Georg , Åberg Sofia
Published: June 2009

The Gaussian linear wave model, which has been successfully used in ocean engineering for more than half a century, is well understood, and there exist both exact theory and efficient numerical algorithms for calculation of the statistical distribution of wave characteristics. It is well suited for moderate seastates and deep water conditions. One drawback, however, is its lack of realism under extreme or shallow water conditions, in particular, its symmetry. It produces waves, which are stochastically symmetric, both in the vertical and in the horizontal direction. From that point of view, the Lagrangian wave model, which describes the horizontal and vertical movements of individual water particles, is more realistic. Its stochastic properties are much less known and have not been studied until quite recently. This paper presents a version of the first order stochastic Lagrange model that is able to generate irregular waves with both crest-trough and front-back asymmetries.
A Novel Shock Processing by High-Intensity Pulsed Ion Beam
Authors: Lei M. K. , Zhu X. P. , Liu C. , Xin J. P. , Han X. G. , Li P. , Dong Z. H. , Wang X. , Miao S. M.
Published: June 2009

A novel shock processing by high-intensity pulsed ion beam (HIPIB) is developed, referred to as ion beam shock processing (IBSP), for surface processing of components with high surface integrity. The IBSP utilizes effectively coupled thermal-dynamic effects of HIPIB irradiation onto materials, characterized by ultrafast surface remelting and solidification, and controlled ablation. As a result, using the IBSP treatment with HIPIB parameters with an ion energy of 200–400 keV and an ion current density of 50–400 A/cm2 with a pulse width of 75 ns, i.e., a power density of 107–108 W/cm2, hardening extending to tens and hundreds of micrometers in depth is achieved on pure Cu and 316L austenitic stainless steel, which is comparable to that of laser shock processing at about two orders higher power density, usually no less than 109–1010 W/cm2. Significant improvements in the overall performance including wear and corrosion resistance, fatigue, and creep properties are found for IBSP treated pure Cu and 316L stainless steel, attributable to the formation of nonequilibrium microstructures into different depths of the processed materials, e.g., amorphous and/or nanocrystalline structure in the heat-affected zone, and high-density defects in the deeper regions with residual compressive stresses caused by shock wave propagation into substrate in which the former is not obtainable in conventional shock processing. Furthermore, purified and polished surfaces free of cracks can be obtained simultaneously under HIPIB irradiation, composing the completeness for effectively enhancing the surface integrity of the processed materials. The coupled thermal-dynamic effects of IBSP assure surface processing of high surface integrity for components, with improved physical and chemical properties and modified surface topography.
Modeling and Prediction of the Flow, Pressure, and Holding Force Generated by a Bernoulli Handling Device
Authors: Brun Xavier F. , Melkote Shreyes N.
Published: June 2009

This paper presents the modeling and prediction of the air flow, pressure, and holding (or lifting) force produced by a noncontact Bernoulli gripper, which is essentially a radial air flow nozzle used to handle small and large rigid and nonrigid materials. Previous studies have demonstrated the turbulent behavior of the flow and the presence of a flow separation region at the nozzle of the gripper. Here, a Reynolds stress model has been implemented in a finite volume based segregated Reynolds-averaged Navier–Stokes solver. Compressible air is modeled to capture the effect of the high flow velocities generated by the nozzle. In addition an experimental setup is designed to validate the model. Experimental results of air pressure and lifting force agree favorably with those predicted by the model. This model could be used to understand the influence of handling variables such as the stand-off distance and air flow rate on the suction pressure distribution and lifting force acting on the handled object.
Metal Removal in EDM Driven by Shifting Secondary Discharge
Authors: Luo Y. F. , Tao Jia
Published: June 2009

Metal removal mechanism in electrical discharge machining (EDM) is revealed as shifting secondary discharges inside a cathodic root. Typical for EDM sinking process, the electrode couple of steel for cathode and copper for anode is used in this investigation. Micrographs of the discharge craters are taken from the surfaces eroded in the continual discharging processes with normal as well as reversed polarities. The apparent difference in crater morphologies between anode and cathode is investigated. The unique cathodic features indicate the existence of frequent spot expulsions of molten metal from the cathodic root during an entire primary discharge pulse. Shifting secondary discharges are discerned as the driving force to the special cathodic metal expulsions. Electrode energy equilibrium is analyzed to account for all the thermal contributors and the tendency of secondary discharges. The compliance of secondary discharges with long-disputed phenomena, such as the discrepancy between energy partition and metal removal, are demonstrated to be exempt from some of the conventional theories. Without the prior observation facilities, such as single pulse discharge, the method and results are made closer to a real EDM die sinking process. Such an insight into complex micro-erosion mechanisms is attempted to correlate better with the well-known consistent process behaviors.
Research Needs: Industrial Spray Processes, Spray Drying, and Heat Transfer
Authors: Janna William S.
Published: June 2009

A survey of researchers and of manufacturers of spraying, drying, and spray heat transfer equipment was conducted. Those that responded provided descriptions of processes and devices that need developmental attention. Several of these problems are described here (eg, a unifying theory of how atomization takes place; a method of evaluating the performance of a spray used to dissolve air in water to enhance mass transfer processes; a comprehensive model for predicting heat transfer from high pressure sprays; etc). It is concluded that many research topics can be gleaned from industry as needs develop and innovative ways are found for sprays to replace conventional methods.
Dusty Shock Waves
Authors: Igra O. , Ben-Dor G.
Published: June 2009

The flow field developed behind shock waves in a pure gaseous medium is well known and documented in all gasdynamics textbooks. This is not the case when the gaseous medium is seeded with small solid particles. The present review treats various cases of shock waves propagation into a gas-dust suspension (dusty shock waves). It starts (chapter 1) with basic definitions of two-phase (gas-dust) suspensions and presents a general form of the conservation equations which govern dusty shock wave flows. In chapter two, the simple case of a steady flow of a suspension consisting of an inert dust and a perfect gas through a normal shock wave is studied. The effect of the dust presence, and of changes in its physical parameters, on the post-shock wave flow are discussed. Obviously, these discussions are limited to relatively weak shock waves (perfect gas). For stronger normal shock waves, the assumption of a perfect gas no longer holds. Therefore, in chapter three, real gas effects (ionization or dissociation) are taken into account when calculating the post-shock flow field. In chapter four, the dust chemistry is included and its effects on the post-shock flow is studied. In order to emphasize the role played by the dust chemistry, a comparison between a reactive and a similar inert suspension is presented. The case of an oblique shock wave in a dusty gas is discussed in chapter five. In all cases treated in chapters two to five the flow is steady; however, in many engineering applications this is not the case. In reality, even for the simplest case of a one-dimensional flow (normal shock wave propagation into quiescent suspension—the dusty shock tube) the shock wave attenuates and the flow field behind it is not steady. This case is treated in chapter six. The cases treated in chapters two to six deal with planar shock waves. However, all explosion generated shock waves in the atmosphere are spherical. Due to the engineering importance of this case, the post-shock flow for spherical shock waves in a dusty gas is studied, in detail, in chapter seven. It is shown in the present review that the dust presence has significant effects on the post-shock flow field. In all cases studied, a relaxation zone is developed behind the shock wave front. Throughout this zone momentum and energy exchange between the two phases of the suspension takes place. Through these interactions a new state of equilibrium is reached. The extent of the relaxation zone depends upon the dust loading ratio, the dust particle diameter, its specific heat capacity, and the dust spatial density. Due to the complexity of conducting experimental investigations with dusty shock waves, the number of published experimental results is very limited. As a result most of the present review contains numerical studies. However, in the few cases where experimental data are available, (e.g. dusty shock tube flow; see chapter six) a comparison between the numerical and experimental results is given.
Optimal Structural Design Under Creep Conditions
Authors: Z˙yczkowski Michał
Published: June 2009

Optimal design of structures, or rather just of simple structural elements working under creep conditions, belongs to the most recent branches of structural optimization: It was initiated by four papers published in the years 1967–1968 (Reitman, Prager, Nemirovsky, and Z˙yczkowski). The most important differences with respect to elastic or plastic design are as follows: factor of time appearing in the constraints, a great variety of constitutive equations of creep or viscoplasticity, of creep rupture hypotheses, creep buckling theories, various definitions of creep stiffness, etc. Moreover, the constraints related to stress–relaxation are quite new. So, it is almost impossible to establish a sufficiently general theory and various types of problems must be treated separately by appropriate methods. On the other hand, the problems of optimization under creep conditions are important in view of metal structures working at elevated temperatures, structures made of plastics, concrete, etc. The paper gives classification of problems and then a review of results obtained for bars, columns, arches, trusses, frames, plates, and shells. Over 30% of those results were obtained at the Technical University of Cracow. This paper discusses specific features of the branch of optimal structural design under consideration as well as perspectives of future research.
Review of Knee Models
Authors: Hefzy Mohamed Samir , Grood Edward S.
Published: June 2009

This paper is a review of static and dynamic models of the human knee joint. Both phenomenological and anatomically based models are discussed. The phenomenological models can be classified into two groups: first, models which consider the human knee to be a simple hinge joint and, second, rheological models. The simple hinge models have generally been used in larger models developed to predict human body dynamics during gait activities. The rheological models, which describe the knee as an equivalent viscoelastic hinge, have been used to describe the response of the knee joint during dynamic loading conditions. Anatomically based models have been used to predict the kinematics and kinetics of the knee and its structural components. The majority of kinetic models have treated static and quasistatic equilibrium conditions, and only a few have addressed nonequilibrium dynamic loading. In reviewing the static and quasistatic models, we have divided them into four groups. First, models developed to determine the forces in the muscles and the ligaments at the knee joint during various activities, second, models developed to determine the forces in the ligaments as a function of joint position, third, models used to determine the contact stresses between the femur and the tibia, and, fourth, more comprehensive models developed to study the stiffness and load–displacement characteristics of the knee joint which include both ligamentous structures and the geometric constraints of the knee. In our survey, we found few models of the patello-femoral joint. A more complete model of the human knee joint describing the interactions between the tibia, femur, patella, and fibula still needs to be developed. On the other hand, the geometric and mechanical properties of a single real knee, required to validate any model are not presently available.
Boiling Heat Transfer in Liquid Metals
Authors: Michiyoshi I.
Published: June 2009

This article presents the state-of-the-art review of boiling heat transfer in various liquid metals paying attention to research papers published in the last 15 years. Particular emphasis is laid on the incipient boiling superheat, diagnosis of natural and forced convection boiling, nucleate pool boiling heat transfer in mercury, sodium, potassium, NaK, lithium, and so on at sub- and near atmospheric pressure, effect of liquid level on liquid metal boiling, subcooling effect due to hydrostatic head on liquid metal boiling, effect of magnetic field on liquid metal boiling, pool boiling crisis under various conditions and intermittent boiling of liquid metal, two-phase flow heat transfer, and natural and forced convection film boiling in saturated and subcooled liquid metals. In conclusion, there still remain some ambiguous and unsolved problems which are pointed out in this article. Further studies are of course required to clarify and solve them in future with both theoretical and experimental approaches.
Continuum Modeling for Repetitive Lattice Structures
Authors: Noor Ahmed K.
Published: June 2009

The status and some recent developments of continuum modeling for repetitive lattice structures are summarized. Discussion focuses on a number of aspects including definition of an effective substitute continuum; characterization of the continuum model; and the different approaches for generating the properties of the continuum, namely, the constitutive matrix, the matrix of mass densities, and the matrix of thermal coefficients. Also, a simple approach is presented for generating the analytic expressions and/or numerical values of the continuum properties. Sample numerical results are presented to demonstrate the effectiveness of the continuum modeling approach. Future directions of research on continuum modeling are identified. These include needed extensions and applications of continuum modeling as well as computational strategies and modeling techniques.
Elastic and Acoustic Resonance Wave Scattering
Authors: Gaunaurd Guillermo C.
Published: June 2009

The present article addresses classical elastic and/or acoustic wave-scattering problems for situations in which the pertinent targets are penetrable. In contrast to impenetrable scatterers, penetrable bodies admit interior fields coupled to the external fields through suitable (sets of) boundary conditions. When the wavelength of the incident radiation is either very long or very short, the scattered echoes returned to an interrogating active sensor can be described in a relatively simple way. This is not the case in the resonance region of the scattering cross section of any penetrable body. This region is sandwiched in between the long-wavelength (Rayleigh) region and the short-wavelength (geometrical) spectral regime. For penetrable (viz, acoustic, elastic, viscoelastic) structures, the resonance region becomes very broad, and results within it are quite difficult to describe analytically, to compute numerically, or to confirm experimentally. Resonance scattering (by definition) implies that the situation at hand occurs within that most troublesome of spectral regimes. We describe a technique particularly useful to simplify and interpret predictions and measurements in the resonance region. This technique exploits the presence of certain “features” clearly observable in the echoes returned by the targets that scatter them. It is by means of these (resonance) features that, for example, different submerged structures can be remotely distinguished from one another. The natural resonances of the structure, not in vacuum, but accounting for its fluid-loaded condition, are communicated to its returned echo in a unique fashion that unambiguously characterizes it as a “fingerprint.” It is always these echoes that we investigate for their “resonance” contents, either in the frequency or time domains. The resonance technique described here, often called the resonance scattering technique (RST), is a linear approximation that makes the understanding of resonance signatures from scatterers not only easier, but possible at all. Results obtainable from strictly classical approaches are so cluttered with information that it is difficult to use them. One simply “cannot see the forest for the trees.” The applications of the RST to various separable and nonseparable configurations are shown. Validating experiments are described, and a bibliography emphasizing the recent target-identification and target-camouflaging aspects of the technique is provided.
Synthesis and hybridization of oligonucleotides modified at AMP sites with adenine pyrrolidine phosphonate nucleotides
Authors: Rejman Dominik , Kočalka Petr , Pohl Radek , Točík Zdeněk , Rosenberg Ivan
Published: June 2009

Three structurally diverse types of the protected pyrrolidine nucleoside phosphonates were prepared as the monomers for the introduction of pyrrolidine nucleotide units into modified oligonucleotides on the solid phase. Two different chemistries were used for incorporation of modified and natural units: the phosphotriester method for the former, i.e., monomers containing N-phosphonoalkyl and N-phosphonoacyl moieties attached to the pyrrolidine ring nitrogen atom, and phosphoramidite chemistry for the latter. Since the synthesized pyrrolidine nucleoside phosphonic acids are close mimics of the 3′-deoxynucleoside 5′-phosphates, the incorporation of one modified unit into oligonucleotides gives rise to one 2′,5′ internucleotide linkage. A series of nonamers containing two or three modified units, as well as the fully modified adenine 15-mer, were synthesized in reverse order, i.e., from the 5′ to the 3′ end of the strand. The measurement of thermal characteristics of the complexes of modified nonamers with the complementary strand revealed a destabilizing effect of the introduced modification. The modified adenine homooligonucleotide, was found to form the most stable complex with oligothymidylate of all the tested modified oligonucleotides in terms of ΔTm per modification.
Occupational eye injury and risk reduction: Kentucky workers’ compensation claim analysis 1994–2003
Authors: McCall B P , Horwitz I B , Taylor O A
Published: June 2009

Background:

Occupational eye injuries are a significant source of injury in the workplace. Little population-based research in the area has been conducted, and is necessary for developing and prioritising effective interventions.

Methods:

Workers’ compensation data from the state of Kentucky for the years 1994–2003 were analysed by demographics, injury nature and cause, cost, and occupational and industrial characteristics. The US Bureau of Labor Statistics’ Current Population Survey was utilised to compute injury rates for demographic and occupational groups.

Results:

There were 10 545 claims of ocular injury, representing 6.29 claims per 10 000 workers on average annually. A substantial drop in the claim rate was found after the state passed monetary penalties for injuries caused by employer negligence or OSHA violations. Claims by men were over three times more likely than those by women to have associated claim costs (OR 0.52; 95% CI 0.32 to 0.85; p = 0.009). The highest eye injury rates per 10 000 of 13.46 (95% CI 12.86 to 14.07) were found for the helpers/labourers occupation, and of 19.95 (95% CI 18.73 to 21.17) for the construction industry. The total cost of claim payments over the period was over $3 480 000, and average cost per claim approximated $331.

Conclusions:

Eye injuries remain a significant risk to worker health, especially among men in jobs requiring intensive manual labour. Evidence showed that increased legislative regulation led to a decline in eye injuries, which was consistent with other recent findings in the area. Additionally, targeting groups most at risk, increasing worker training, providing effective eye protection equipment, and developing workplace safety cultures may together reduce occupational eye injuries.
The burden of road traffic injuries in Nigeria: results of a population-based survey
Authors: Labinjo M , Juillard C , Kobusingye O C , Hyder A A
Published: June 2009

Background:

Mortality from road traffic injuries in sub-Saharan Africa is among the highest in the world, yet data from the region are sparse. To date, no multi-site population-based survey on road traffic injuries has been reported from Nigeria, the most populated country in Africa.

Objective:

To explore the epidemiology of road traffic injury in Nigeria and provide data on the populations affected and risk factors for road traffic injury.

Design:

Data from a population-based survey using two-stage stratified cluster sampling.

Subjects/setting:

Road traffic injury status and demographic information were collected on 3082 respondents living in 553 households in seven of Nigeria’s 37 states.

Main outcome measures:

Incidence rates were estimated with confidence intervals based on a Poisson distribution; Poisson regression analysis was used to calculate relative risks for associated factors.

Results:

The overall road traffic injury rate was 41 per 1000 population (95% CI 34 to 49), and mortality from road traffic injuries was 1.6 per 1000 population (95% CI 0.5 to 3.8). Motorcycle crashes accounted for 54% of all road traffic injuries. The road traffic injury rates found for rural and urban respondents were not significantly different. Increased risk of injury was associated with male gender among those aged 18–44 years, with a relative risk of 2.96 when compared with women in the same age range (95% CI 1.72 to 5.09, p<0.001).

Conclusions:

The road traffic injury rates found in this survey highlight a neglected public health problem in Nigeria. Simple extrapolations from this survey suggest that over 4 million people may be injured and as many as 200 000 potentially killed as the result of road traffic crashes annually in Nigeria. Appropriate interventions in both the health and transport sectors are needed to address this significant cause of morbidity and mortality in Nigeria.
The effect of education and home safety equipment on childhood thermal injury prevention: meta-analysis and meta-regression
Authors: Kendrick D , Smith S , Sutton A J , Mulvaney C , Watson M , Coupland C , Mason-Jones A
Published: June 2009

Objective:

To evaluate whether home safety education and safety equipment provision increases thermal injury prevention practices or reduces thermal injury rates and whether the effect of interventions differs by social group.

Methods:

Systematic review and meta-analysis using individual participant data (IPD) evaluating home safety education with or without provision of free or discounted safety equipment provided to children or young people aged 0–19 years. Main outcome measures: possession of functional smoke alarm, fitted fireguard and fire extinguisher; keeping hot drinks or food and keeping matches or lighters out of reach; having a safe hot water temperature and rate of medically attended thermal injuries.

Results:

Home safety interventions were effective in increasing the proportion of families with a functional smoke alarm (odds ratio (OR) 1.83, 95% CI 1.22 to 2.74) and with a safe hot tap water temperature (OR 1.35, 95% CI 1.01 to 1.80). There was some evidence they increased possession of fitted fireguards (OR 1.39, 95% CI 1.00 to 1.94), but there was a lack of evidence that interventions reduced medically attended thermal injury rates (incident rate ratio (IRR) 1.12, 95% CI 0.81 to 1.56). There was no consistent evidence that the effectiveness of interventions varied by social group.

Conclusions:

Home safety education, especially with the provision of safety equipment, is effective in increasing some thermal injury prevention practices, but there is insufficient evidence to show whether this also reduces injury rates.
Building national estimates of the burden of road traffic injuries in developing countries from all available data sources: Iran
Authors: Bhalla K , Naghavi M , Shahraz S , Bartels D , Murray C J L
Published: June 2009

Objective:

To use a range of existing information sources to develop a national snapshot of the burden of road traffic injuries in one developing country—Iran.

Methods:

The distribution of deaths was estimated by using data from the national death registration system, hospital admissions and outpatient visits from a time-limited hospital registry in 12 of 30 provinces, and injuries that received no institutional care using the 2000 demographic and health survey. Results were extrapolated to national annual incidence of health burden differentiated by age, sex, external cause, nature of injuries and institutional care.

Results:

In 2005, 30 721 Iranians died annually in road traffic crashes and over one million were injured. The death rate (44 per 100 000) is the highest of any country in the world for which reliable estimates are available. Road traffic injuries are the third leading cause of death in Iran. While young adults are at high risk in non-fatal crashes, the elderly have the highest total death rates, largely due to pedestrian crashes. While car occupants lead the death count, motorised two-wheeler riders dominate hospital admissions, outpatient visits and health burden.

Conclusions:

Reliable estimates of the burden of road traffic injuries are an essential input for rational priority setting. Most low income countries are unlikely to have national injury surveillance systems for several decades. Thus national estimates of the burden of injuries should be built by collating information from all existing information sources by appropriately correcting for source specific shortcomings.
The Preventing Australian Football Injuries with Exercise (PAFIX) Study: a group randomised controlled trial
Authors: Finch C , Lloyd D , Elliott B
Published: June 2009

Background:

Knee injuries are a major injury concern for Australian Football players and participants of many other sports worldwide. There is increasing evidence from laboratory and biomechanically focused studies about the likely benefit of targeted exercise programmes to prevent knee injuries. However, there have been few international studies that have evaluated the effectiveness of such programmes in the real-world context of community sport that have combined epidemiological, behavioural and biomechanical approaches.

Objective:

To implement a fully piloted and tested exercise training intervention to reduce the number of football-related knee injuries. In so doing, to evaluate the intervention’s effectiveness in the real-world context of community football and to determine if the underlying neural and biomechanical training adaptations are associated with decreased risk of injury.

Setting:

Adult players from community-level Australian Football clubs in two Australian states over the 2007–08 playing seasons.

Methods:

A group-clustered randomised controlled trial with teams of players randomly allocated to either a coach-delivered targeted exercise programme or usual behaviour (control). Epidemiological component: field-based injury surveillance and monitoring of training/game exposures. Behavioural component: evaluation of player and coach attitudes, knowledge, behaviours and compliance, both before and after the intervention is implemented. Biomechanical component: biomechanical, game mobility and neuromuscular parameters assessed to determine the fundamental effect of training on these factors and injury risk.

Outcome measures:

The rate and severity of injury in the intervention group compared with the control group. Changes, if any, in behavioural components. Process evaluation: coach delivery factors and likely sustainability.
Origin and use of the 100 cigarette criterion in tobacco surveys
Authors: Bondy S J , Victor J C , Diemert L M
Published: June 2009

Truly global standards and definitions will likely never exist for tobacco control surveillance. One difference across definitions of smoking status is whether or not a lifetime consumption of 100 cigarettes is a necessary criterion for ever and current smoking. Frequently asked questions about this measure demonstrate a need for information on its development and appropriateness in different settings. This commentary attempts to assemble information on the origin and adoption of this measure and provide some critical commentary on its usefulness.

The question has been traced to Canadian and American mortality cohort studies from the mid-1950s. From there it has spread to inconsistent use in many settings. To our knowledge, it was not originally (or since) empirically defined as a threshold of exposure related to health consequences or future smoking risk when used in youth.

Anecdotal evidence over several decades, however, shows the question has pragmatic utility in self-report data collection. It is a useful, if somewhat arbitrary, screener for “never regular” tobacco use among adults, where never smoking needs to be defined in data collection. Use of the criterion may lower prevalence estimates somewhat. Definitions must always be considered when creating time-trends or international comparisons.

There are also circumstances where it is inappropriate to exclude individuals who do not meet this criterion from further data collection, or reports. For research in youth, the criterion typically should be used only with more detailed information about experimentation, but it may be a useful additional indicator of established smoking.
Health Implications of Musculoskeletal fitness
Authors: Payne Nancy , Gledhill Norman , Katzmarzyk Peter T. , Jamnik Veronica , Ferguson Steven
Published: June 2009

Although it is well documented that physical activity participation can bring about improvements in musculoskeletal fitness, related health implications have only been substantiated in the elderly. Currently, interpretations of the results of musculoskeletal fitness appraisals for the general population are based largely on an intuitive belief that enhanced musculoskeletal fitness is associated with higher levels of health throughout adulthood. Musculoskeletal fitness was measured in 312 females and 259 males aged 15-69 years. Health levels were determined using two previously validated questionnaires and expressed as composite health scores derived from principal components analysis. Grip strength, push strength, pull strength, push-ups, and trunk forward flexion were significant predictors of health scores after controlling for the potentially confounding effects of gender, age, aerobic fitness, waist circumference, and smoking status. These findings indicate that musculoskeletal fitness is related to health in males and females aged 15 to 69 years. Key Words: health-related fitness, fitness assessment, muscular strength, muscular endurance, trunk flexibility
The Effect of Endurance Training on Phosphoinositide Metabolism of Extensor Digitorum Longus in Rats
Authors: Oueslati Habib , Gardiner Phillip
Published: June 2009

We tested the hypothesis that endurance training results in changes in inositol triphosphate (InsP3) production from membrane phosphoinositides in trained muscles during contractile activity, which might have implications for fatigue involving calcium-release mechanisms. The extensor digitorum longus (EDL) muscles of endurance-trained rats were measured for membrane phosphoinositides, fatigability, and the production of inositol phosphates resulting from a 10-s tetanic contraction in vitro. In the latter, training resulted in a 22% increase in the production of inositol phosphates, in spite of lower phosphoinositides per muscle. In a separate group of animals, pretreatment of EDL in vitro for 15 min with 20 mM lithium resulted in a gradual decrease in tetanic forces at 100 Hz and increased fatigability. These results show for the first time that this metabolic system adapts to increased use and may contribute to the associated increased fatigue resistance, through its modulation of calcium release by sarcoplasmic reticulum. Key words: fatigue, exercise training, inositol phosphates, second messenger
Short-Term Training: When Do Repeated Bouts of Resistance Exercise Become Training?
Authors: Phillips Stuart M.
Published: June 2009

Chronic resistance training induces increases in muscle fibre cross-sectional area (CSA), otherwise known as hypertrophy. This is due to an increased volume percentage of myofibrillar proteins within a given fibre. The exact time-course for muscle fibre hypertrophy is not well-documented but appears to require at least 6-7 weeks of regular resistive training at reasonably high intensity before increases in fibre CSA are deemed significant. Proposed training-induced changes in neural drive are hypothesized to increase strength due to increased synchrony of motor unit firing, reduced antagonist muscle activity and/or a reduction in any bilateral strength deficit. Nonetheless, increases in muscle protein synthesis were observed following an isolated bout of resistance exercise. In addition, muscle balance was positive, following resistance exercise when amino acids were infused/ingested. This showed that protein accretion occurred during the postexercise period. The implications of this hypothesis for training-induced increases in strength are discussed. Key words: hypertrophy, muscle protein synthesis, muscle protein breakdown, myofibrillar protein, strength.
Effects of Short-Term Training on Physiologic Properties of Human Motor Units
Authors: Doherty Timothy J.
Published: June 2009

The human neuromuscular system possesses a remarkable ability to adapt to any change in the demands placed upon it. Adaptation to training or disuse is reflected in the activation patterns and physiologic properties of the motor unit (MU) pool in a given muscle group. This review summarizes the studies that have examined such adaptation at the level of the single MU. Disuse, as revealed by electrophysiologic studies, results in impaired MU recruitment and smaller twitch tensions in tow and high threshold MUs. Alternatively, short-term training improves MU recruitment and generally results in larger MU twitch tensions. A method has been developed to physiologically characterize and longitudinally follow single thenar MUs. Studies utilizing these methods have demonstrated that MUs differing in their baseline physiologic characteristics respond very differently to identical short-term training programs. These observations at the single MU level provide insight into training adaptations in whole muscles and muscle groups. Key words: motor unit, training, disuse, electromyography
Estrogen and Gender Effects on Muscle Damage, Inflammation, and Oxidative Stress
Authors: Tiidus Peter M.
Published: June 2009

Information suggests that there may be gender-based differences in skeletal muscle responses to damaging exercise. Evidence demonstrates that estrogen has strong antioxidant properties and may be an important factor in maintaining postexercise membrane stability and limiting creatine kinase (CK) leakage from damaged muscle in female animals. Research demonstrates effects of estrogen and possible gender differences in other morphological and biochemical indices of postexercise muscle damage and leukocyte invasion. Nevertheless, there are conflicting findings suggesting that in some in vivo exercise models, estrogen administration has limited ability to affect exercise-induced oxidative stress and muscle damage and max cause loss of tissue vitamin C. Gender differences appear to exist in tissue levels of other important antioxidants such as vitamin E and glutathione. More research is needed to fully define the potential for estrogen to influence postexercise muscle damage and the inflammatory response and to determine the mechanisms by which it may operate. Key words: exercise, neutrophils, creatine kinase, vitamin E, vitamin C
Sex Differences in Substrate Metabolism and Energy Homeostasis
Authors: Cortright Ronald N. , Koves Timothy R.
Published: June 2009

Females differ remarkably from males in the mechanisms that regulate substrate utilization and energy homeostasis. Females appear to be less affected in terms of growth and loss of body tissues when subjected to chronic periods of negative energy balance. The physiological trade-off appears to be a stronger propensity toward retention of fat mass during times of energy surfeit. The mechanism(s) that account for sex differences in energy metabolism are not known but most likely involve the sex steroids. Recent discoveries in the areas of endocrinology and metabolism may provide new insights into differences in the control of food intake and energy conservation between the sexes. Finally, the study of the mechanism(s) involved in the regulation of skeletal muscle lipid metabolism represents a new frontier in skeletal muscle bioenergetics, and new discoveries may provide further explanations for the observed sex differences in substrate utilization and response(s) to alterations in energy homeostasis. Key words: Sex differences, growth, body composition, survival, substrate utilization
Fatty Acid Transport Proteins Facilitate Fatty Acid Uptake in Skeletal Muscle
Authors: Luiken Joost J.F.P. , Glatz Jan F.C. , Bonen Arend
Published: June 2009

In view of the importance of long chain fatty acids (LCFAs) to many cellular processes, it may be desirable to regulate the LCFA disposition in the cell. Such regulation may be present at the level of the plasma membrane, since a number of putative LCFA transport proteins have been cloned. The development of a model system of giant vesicles has proven to be important in identifying the metabolic role of the LCFA transport system. LCFA transport rates and transporters (FABPpm and FAT/CD36) are scaled with oxidative capacity of heart and muscle. FAT/CD36 is a critical LCFA transport protein in muscle. With chronic contraction the increase in this protein also results in an increase in LCFA transport. Most importantly, LCFA transport is also increased acutely by muscle contraction, involving the translocation of FAT/CD36 from intracellular depots to the surface of the muscle cell. The acute (minutes) and chronic (days) regulation of LCFA transporters and transport by muscle may be an important mechanism for LCFA utilization during exercise and adaptable with training and with a metabolic disease such as type 2 diabetes. Key words: FAT/CD36, FABPpm, giant vesicles, transport
Age-Related Variations of Serum CK and CK MB Response in Females
Authors: Arnett Mark G. , Hyslop Richard , Dennehy Carolyn A. , Schneider Carole M.
Published: June 2009

The objective was to determine whether serum creatine kinase (CK) and serum CK MB activity following exercise-induced muscle damage activity differs among females of varying menarchial status and to determine whether there is a relationship between serum estradiol (E2) concentration, CK, and CK MB activity. Fifteen menarchial (M), 15 premenarchial (P), and 10 postmenopausal (PM) females participated in the study. Exercise consisted of eccentric hamstring contractions. Estradiol concentrations were significantly higher in M women (p = .0001; M, 125.0 ± 20.8 pg/mL, P, 54.6 ± 38.6 pg/mL, PM, 46.2 ± 34.6 pg/mL). Menarchial women had lower resting CK and CK MB activity and responded with a higher efflux of CK and CK MB post exercise (p = .0001). An inverse relationship was found between E2 concentration and baseline CK (p = .02) and CK MB activity (p = .006). No relationship existed between post exercise efflux of CK and CK MB and E2 concentration. At rest, E2 influenced CK and CK MB activity across menarchial levels. However, E2 did not significantly reduce the level of CK and CK MB activity following this intense bout of eccentric exercise. Key words: exercise-induced muscle damage, estradiol, menarhial, premenarchial, postmenopausal
Canadian Musculoskeletal Fitness Norms
Authors: Payne Nancy , Gledhill Norman , Katzmarzyk Peter T. , Jamnik Veronica K. , Keir Peter J.
Published: June 2009

The purpose of this report is to provide representative norms for measurements of musculoskeletal fitness (partial curl-ups, vertical jump, and leg power) for which Canadian norms are not currently available. Partial curl-ups, vertical jump, trunk flexion (sit and reach), grip strength, muscular endurance (push-ups), body mass index, and subcutaneous adiposity (sum of five skinfolds) were assessed, and leg power was calculated in 571 self-reportedly healthy participants (312 females and 259 males) aged 15-69 yr. The representativeness of the sample was confirmed by statistically comparing the fitness characteristics of the participants in the present study to those in the Canada Fitness Survey of 1981 and the Campbell's Survey of 1988. Normative data for partial curl-ups, vertical jump, and leg power were generated for males and females in six age groups (15-19, 20-29, 30-39, 40-49, 50-59, 60-69) for use in fitness appraisal protocols for the Canadian population. Key Words: partial curl-ups, vertical jump, leg power, normative data
The Influence of Elbow Joint Angle on Different Phases of Force Development During Maximal Voluntary Contraction
Authors: Jaskólski Artur , Kisiel Katarzyna , Adach Zdzisław , Jaskólska Anna
Published: June 2009

The first aim of the study was to find an elbow joint angle at which muscle can produce maximum voluntary force (Lo(MVC)) and to compare that angle with an angle at which the fastest rates of force development occur (Lo). The second aim of the study was to find if changes in MVC and force development speed at an angle smaller (Ls) and larger (Ll) than the optimal angle depend on whether Ls and Ll were compared to Lo or Ls and Ll to Lo(MVC) Twenty-four male physical education students were tested four times using the BIODYNA dynamometer to measure torque versus time at an optimal length, as well as at lengths that were shorter (Ls = optimal −30°) and longer (Ll = optimal + 50°). The average values of optimal angles for force development indices (Lo) were similar to the angle at which maximum force was produced (Lo(MVC)); however, there was a small (5 - 10°) difference between Lo and Lo(MVO) in the majority of subjects.The results showed that during elbow flexion with the forearm in the midrange position the difference between Lo and Lo(MVC) was small and did not affect MVC; however, it had a significant effect on the relation between joint angle and force development speed. Key words: optimal length, force development, MVC, elbow joint angle
Revisiting the Role of Physical Activity and Exercise in the Treatment of Type 2 Diabetes
Authors: Tudor-Locke Catrine E. , Bell Rhonda C. , Myers Anita M.
Published: June 2009

There is tremendous potential for improving glycemic control, insulin sensitivity, and cardiovascular risk factors through increased physical activity in individuals with Type 2 diabetes. The demonstrated effects of structured endurance exercise on select outcomes compare favourably with those of typical pharmacological treatment modalities. Adherence to these types of program is problematic, however. We know less about the expected effects of lifestyle-based physical activity. Preliminary results require further investigation, given the apparent acceptability of these programs in this population, however. The effects of resistance training on cardiovascular risk factors to date likely limit its application as an adjunctive therapy for individuals with Type 2 diabetes. The question is no longer "can exercise/physical activity benefit the individual with Type 2 diabetes?" The answer is yes. Future research needs to refine questions regarding type, dose, and magnitude of effects of physical activity (and its subcategory exercise) on glycemic control, insulin sensitivity, and on risk factors for cardiovascular disease within the context of program acceptability and feasibility. Key words: walking, obesity, glycemic control, insulin sensitivity, hypertension