Uneven running: How does trunk-leaning affect the lower-limb joint mechanics and energetics?

This study aimed to investigate the role of trunk posture in running locomotion. Twelve recreational runners ran in the laboratory across even and uneven ground surface (expected 10 cm drop-step) with three trunk-lean angles from the vertical (self-selected, ∼15°; anterior, ∼25°; posterior, ∼0°) while 3D kinematic and kinetic data were collected using a 3D motion-capture-system and two embedded force-plates. Two-way repeated measures ANOVAs (α = 0.05) compared lower-limb joint mechanics (angles, moments, energy absorption and generation) and ground-reaction-force parameters (braking and propulsive impulse) between Step (level and drop) and Posture conditions. The Step-by-Posture interaction revealed decreased hip energy generation, and greater peak knee extension moment in the drop-step during running with posterior versus anterior trunk-lean. Furthermore, energy absorption across hip and ankle nearly doubled in the drop-step across all running conditions. The Step main effect revealed that the knee and ankle energy absorption, ankle energy generation, ground-reaction-force, and braking impulse significantly increased in the drop-step. The Posture main effect revealed that, compared with a self-selected trunk-lean, the knee's energy absorption/generation, ankle's energy generation and the braking impulse were either retained or attenuated when leaning the trunk anteriorly. The opposite effects occurred with a posterior trunk-lean. In conclusion, while the pronounced mechanical ankle stress in drop-steps is marginally affected by posture, changing the trunk-lean reorganizes the load distribution across the knee and hip joints. Leaning the trunk anteriorly in running shifts loading from the knee to the hip not only in level running but also when coping with ground-level changes.Highlights Changing the trunk-lean when running reorganizes the load distribution across the knee and hip joints.Leaning the trunk anteriorly from a habitual trunk posture during running attenuates the mechanical stress on the knee, while the opposite effect occurs with a posterior trunk-lean, irrespective to the ground surface uniformity.The effect of posture on pronounced mechanical ankle stress in small perturbation height during running is marginal.Leaning the trunk anteriorly shifts loading from the knee to the hip not only in level running but also when coping with small perturbation height

Ablation of solids by femtosecond lasers: ablation mechanism and ablation thresholds for metals and dielectrics

The mechanism of ablation of solids by intense femtosecond laser pulses is described in an explicit analytical form. It is shown that at high intensities when the ionization of the target material is complete before the end of the pulse, the ablation mechanism is the same for both metals and dielectrics. The physics of this new ablation regime involves ion acceleration in the electrostatic field caused by charge separation created by energetic electrons escaping from the target. The formulae for ablation thresholds and ablation rates for metals and dielectrics, combining the laser and target parameters, are derived and compared to experimental data. The calculated dependence of the ablation thresholds on the pulse duration is in agreement with the experimental data in a femtosecond range, and it is linked to the dependence for nanosecond pulses.Comment: 27 pages incl.3 figs; presented at CLEO-Europe'2000 11-15 Sept.2000; papers QMD6 and CTuK11

A comparison of the Nordtest and Japanese test methods for the moisture buffering performance of building materials

Two test methods, one worked out in a Nordtest project and the other available as a Japanese Industrial Standard, both developed to characterize building materials with respect to moisture buffering performance, are analyzed in detail by a numerical study on four different materials. Both test methods are based on a similar kind of dynamic loading, but the specifications of each test protocol vary. Therefore, the sensitivity of the test protocols is investigated by varying different protocol parameters. Subsequently, the practical applicability of the obtained values is investigated by confronting the values obtained for the four materials with the dynamic response of a small room with each of the materials used in turns as finishing material. Finally, the results determined according to the dynamic test protocol are compared with values calculated from steady-state material data.status: publishe

Integrating water quality models in the High Level Architecture (HLA) environment

International audienceHLA (High Level Architecture) is a computer architecture for constructing distributed simulations. It facilitates interoperability among different simulations and simulation types and promotes reuse of simulation software modules. The core of the HLA is the Run-Time Infrastructure (RTI) that provides services to start and stop a simulation execution, to transfer data between interoperating simulations, to control the amount and routing of data that is passed, and to co-ordinate the passage of simulated time among the simulations. The authors are not aware of any HLA applications in the field of water resources management. The development of such a system is underway at the UFZ -Centre for Environmental Research, Germany, in which the simulations of a hydrodynamic model (DYNHYD), eutrophication model (EUTRO) and sediment and micro-pollutant transport model (TOXI) are interlinked and co-ordinated by the HLA RTI environment. This configuration enables extensions such as (i) "cross-model" uncertainty analysis with Monte Carlo Analysis: time synchronisation allows EUTRO and TOXI simulations to be made after each successive simulation time step in DYNHYD, (ii) information transfer from EUTRO to TOXI to compute organic carbon fractions of particulate matter in TOXI, (iii) information transfer from TOXI to EUTRO to compute extinction coefficients in EUTRO and (iv) feedback from water quality simulations to the hydrodynamic modeling

Unconventional magnetism in all-carbon nanofoam

We report production of nanostructured carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniques revealed that the system contains both sp2 and sp3 bonded carbon atoms. The material is a novel form of carbon in which graphite-like sheets fill space at very low density due to strong hyperbolic curvature, as proposed for ?schwarzite?. The foam exhibits ferromagnetic-like behaviour up to 90 K, with a narrow hysteresis curve and a high saturation magnetization. Such magnetic properties are very unusual for a carbon allotrope. Detailed analysis excludes impurities as the origin of the magnetic signal. We postulate that localized unpaired spins occur because of topological and bonding defects associated with the sheet curvature, and that these spins are stabilized due to the steric protection offered by the convoluted sheets.Comment: 14 pages, including 2 tables and 7 figs. Submitted to Phys Rev B 10 September 200

Ab initio quantum mechanical simulations confirm the formation of all postulated species in ionic dissociation

A single sodium chloride molecule in aqueous solution was simulated by the ab initio quantum mechanical charge field-molecular dynamics (QMCF-MD) approach. During a series of simulations the solvated molecule (CIP), dissociated solvated ions and - most noticeably - a solvent separated ion pair (SSIP) were observed and the structural and dynamical characteristics of these systems were investigated. In addition to a detailed structural analysis of the observed species, vibrational spectra and charge distributions were calculated to elucidate the mechanism of the NaCl dissociation

A study on drug prescribing pattern in psychiatry out-patient department from a tertiary care teaching hospital

Background: The burden of illness resulting from psychiatric and behavioral disorders is enormous; although, it remains grossly under represented by conventional public health statistics, which focus on mortality rather than the morbidity or dysfunction. Therefore, the study was carried out to find out morbidity pattern of psychiatric diseases and prescribing trends of psychotropic drugs.Methods: A prospective observational study was conducted in psychiatry out-patient department of a tertiary care hospital for 3 months. Diagnosis was made according to ICD-10 criteria. Prescription pattern was analyzed using World Health Organization (WHO) drug indicators.Results: Of 520 patients analyzed, 52.31% were males and 47.69% were females, 72.31% were <45 years. Depression 42.88%, schizophrenia 23.08%, bipolar mood disorders 17.88%, and anxiety 9.04% accounted for 92.88% of cases. Among the total of 1092 psychotropic drugs prescribed, 1056 (96.7%) were oral formulations. Average number of psychotropic drugs per prescription was 2.1 ± 0.8. 20.58% of the prescriptions contained fixed dose combinations. About 28.75% drugs were prescribed by generic name. Utilization from the WHO and National essential medical list were 28.57% and 38.64%, respectively. The prescribing frequency of anxiolytics, anti-depressants, anti-psychotics, anti-cholinergics, and anti-mania drugs was 30.04% (328/1092), 25.46% (278/1092), 25.37% (277/1092), 11.54% (126/1092), and 7.6% (83/1092), respectively. Clonazepam, olanzapine, escitalopram, carbamazepine and trihexyphenidyl were the most commonly prescribed benzodiazepines (BZD), antipsychotic, antidepressants, mood stabilizer and anti-cholinergics, respectively.Conclusion: Utilization pattern of the psychotropic drugs were in accordance to the recommendations of various treatment guidelines. BZD were the most commonly prescribed psychotropic drugs

A review of the peri-operative management of paediatric burns: Identifying adverse events

Background. Burn injuries are common in poverty-stricken countries. The majority of patients with large and complex burns are referred to burn centres. Of the children who qualify for admission, according to burn admission criteria, about half require some kind of surgical procedure to obtain skin cover. These range from massive full-thickness fire burns to skin grafts for small, residual unhealed wounds. Burn anaesthetic procedures are of the most difficult to perform and are known for high complication rates. Reasons include peri-operative sepsis, bleeding, issues around thermoregulation, the hypermetabolic state, nutritional and electrolyte issues, inhalation injuries and the amount of movement during procedures to wash patients, change drapes and access different anatomical sites. The appropriate execution of surgery is therefore of the utmost importance for both minor and major procedures.Objective. To review the peri-operative management and standard of surgical care of burnt children.Methods. This was a retrospective review and analysis of standard peri-operative care of burnt children at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa. A total of 558 children were operated on and supervised by the first author. Factors that could adversely affect surgical and anaesthetic outcomes were identified.Results. There were 257 males and 301 females in this study, with an average age of 50.1 months and average weight of 19.5 kg. The total body surface area involved was 1 - 80%, with an average of 23.5%. Inhalational injury was present in 11.3%, pneumonia in 13.1%, wound sepsis in 20.8%, and septicaemia in 9.7%, and organ dysfunction in more than one organ was seen in 6.1%. The average theatre temperature during surgery was 30.0°C. Core temperatures recorded at the start, halfway through and at completion of surgery were 36.9°C, 36.8°C and 36.5°C, respectively. The average preoperative and postoperative haemoglobin levels were 11.28 g/dL and 9.64 g/dL, respectively. Blood loss was reduced by the use of clysis from 1.5 mL/kg/% burn to 1.4 mL/kg/% burn. Adverse intraoperative events were seen in 17.6% of children.Conclusion. Burn surgery is a high-risk procedure and comorbidities are common. Anaesthesia and surgery must be well planned and executed with special reference to temperature control, rapid blood loss, preceding respiratory illnesses and measures to reduce blood loss