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Sporadic Alzheimer’s disease (sAD) represents a serious and growing worldwide economic and healthcare burden. Almost 95% of current AD patients are associated with sAD as opposed to patients presenting with well-characterized genetic mutations that lead to AD predisposition, i.e., familial AD (fAD). Presently, the use of transgenic (Tg) animals overexpressing human versions of these causative fAD genes represents the dominant research model for AD therapeutic development. As significant differences in etiology exist between sAD and fAD, it is perhaps more appropriate to develop novel, more sAD-reminiscent experimental models that would expedite the discovery of effective therapies for the majority of AD patients. Here we present the oDGal mouse model, a novel model of sAD that displays a range of AD-like pathologies as well as multiple cognitive deficits reminiscent of AD symptomology. Hippocampal cognitive impairment and pathology were delayed with N-acetyl-cysteine (NaC) treatment, which strongly suggests that reactive oxygen species (ROS) are the drivers of downstream pathologies such as elevated amyloid beta and hyperphosphorylated tau. These features demonstrate a desired pathophenotype that distinguishes our model from current transgenic rodent AD models. A preclinical model that presents a phenotype of non-genetic AD-like pathologies and cognitive deficits would benefit the sAD field, particularly when translating therapeutics from the preclinical to the clinical phase.

Magnetic fields, spontaneously generated around laser heating nonuniformities, have been found to invert and enhance electron pressure perturbations in the conduction zones of laser-produced plasmas without applied magnetic fields. The application of a sufficiently strong magnetic field is predicted to damp this phenomenon, but may instead result in magneto-thermal instability. Two-dimensional Vlasov–Fokker–Planck simulations of the conduction zone of laser-produced plasmas, subject to externally applied magnetic fields of different field strengths, are performed. The effects of non-locality upon extended collisional transport terms and instability thresholds are investigated. It is found that magnetized transport terms Righi–Leduc heat flow and thermoelectric heat flow are strongly enhanced by non-locality (up to twofold), even at the top of the temperature gradient, due to larger magnetization of the mediating hot electrons (relative to their thermal counterparts). Meanwhile, the Nernst effect efficiently advects magnetic field out of the conduction zone before instability (which requires Hall parameters, χ>0.1) can take hold.

Extended-magnetohydrodynamics (MHD) transports magnetic flux and electron energy in high-energy-density experiments, but individual transport effects remain unobserved experimentally. Two factors are responsible in defining the transport: electron temperature and electron current. Each electron energy transport term has a direct analog in magnetic flux transport. To measure the thermally driven transport of magnetic flux and electron energy, a simple experimental configuration is explored computationally using a laser-heated pre-magnetized under-dense plasma. Changes to the laser heating profile precipitate clear diagnostic signatures from the Nernst, cross-gradient-Nernst, anisotropic conduction, and Righi-Leduc heat-flow. With a wide operating parameter range, this configuration can be used in both small and large scale facilities to benchmark MHD and kinetic transport in collisional/semi-collisional, local/non-local, and magnetized/unmagnetized regimes.

We present kinetic two-dimensional Vlasov-Fokker-Planck simulations, including both self-consistent magnetic fields and ablating ion outflow, of a planar ablating foil subject to nonuniform laser irradiation. Even for small Hall parameters (ωτ_{ei}≲0.05) self-generated magnetic fields are sufficient to invert and enhance pressure perturbations. The mode inversion is caused by a combination of the Nernst advection of the magnetic field and the Righi-Leduc heat flux. Nonlocal effects modify these processes. The mechanism is robust under plasma conditions tested; it is amplitude independent and occurs for a broad spectrum of perturbation wavelengths, λ_{p}=10-100μm. The ablating plasma response to a dynamically evolving speckle pattern perturbation, analogous to an optically smoothed beam, is also simulated. Similar to the single-mode case, self-generated magnetic fields increase the degree of nonuniformity at the ablation surface by up to an order of magnitude and are found to preferentially enhance lower modes due to the resistive damping of high mode number magnetic fields.

Macrophage-derived foam cells are the predominant component of arterial plaques in the early stages of atherosclerosis. One factor that poses a major risk for plaque development is high levels of plasma low-density lipoprotein (LDL) as a result of a high-fat meal. In order to better understand how an individuals' diet affects arterial plaque deposition via the process of foam cell formation, we measured the acute circulating monocyte activity response after consuming a high-fat meal (85% of daily fat allowance).Venous blood samples from 17 participants were acquired on a FlowSight. Samples were analyzed to identify nonclassical (CD14+/16+) and classical (CD14+/16-) monocytes. We measured monocyte concentration, adhesion molecule expression, CD36 expression, and oxidized LDL (oxLDL) endocytosis for preprandial 1, 3, and 5 h postprandial.Consuming a high-fat meal caused increases in oxLDL uptake, adhesion molecule expression, and CD36 expression in both classical and nonclassical monocytes, with the nonclassical monocytes responding with larger increases than the classical monocytes.These results suggest that consumption of a high-fat meal increased the potential of monocytes to become foam cells, and implicates nonclassical monocytes as having greater potential than classical monocytes to become foam cells. © 2016 International Clinical Cytometry Society.

This paper discusses the interrelationship between retinal and choroidal blood flow, citing particularly the circulatory changes in light and dark adaptation, and the response vessels to hypoxia. The problems of diabetic retinopathy are also considered.

We developed a three-step protocol to quantify the efficacy of disinfectant wipes, their ability to remove and prevent microbial transfer from surfaces and their overall antimicrobial activity. Meticillin-resistant (MRSA) or -susceptible (MSSA) Staphylococcus aureus (6-7 log(10)cfu) were inoculated onto stainless steel discs with or without organic load and dried. Grapefruit extract-containing test wipes and unmedicated control wipes were used. In step 1, wipes were mechanically rotated against surfaces for 10s at 60rpm, exerting a weight of 100+/-5g. Bacterial removal was assessed by transferring the steel discs to neutraliser, resuspending and counting remaining bacteria. In step 2, bacterial transfer from wipes was assessed by eight consecutive mechanical adpression transfers to agar/neutraliser plates. Step 3 was the measurement of antimicrobial activity by direct inoculation of the wipes for 10s followed by neutralisation and enumeration. Test wipes achieved a significantly higher bacterial cell removal than control wipes on all surfaces (P

This study reports a two-year programme of attempted eradication of Legionella colonization in the potable water supply of a 1000-bed tertiary care teaching hospital in Wales. There was a simultaneous, point-of-care, sterile-water-only policy for all intensive care units (ICU) and bone marrow and renal transplant units in order to prevent acquisition of nosocomial Legionnaires' disease. The programme was initiated following a case of nosocomial pneumonia caused by Legionella pneumophila serogroup 1-Bellingham-like genotype A on the cardiac ICU. The case occurred 14 days after mitral and aortic valve replacement surgery. Clinical and epidemiological investigations implicated aspiration of hospital potable water as the mechanism of infection. Despite interventions with chlorine dioxide costing over 25000 UK pounds per annum, Legionella has remained persistently present in significant numbers (up to 20000 colony forming units/L) and with little reduction in the number of positive sites. Two further cases of nosocomial disease occurred over the following two-year period; in one case, aspiration of tap water was implicated again, and in the other case, instillation of contaminated water into the right main bronchus via a misplaced nasogastric tube was implicated. These cases arose because of inadvertent non-compliance with the sterile-water-only policy in high-risk locations. Enhanced clinical surveillance over the same two-year period detected no other cases of nosocomial disease. This study suggests that attempts at eradication of Legionella spp. from complex water systems may not be a cost-effective measure for prevention of nosocomial infections, and to the best of our knowledge is the first study from the UK to suggest that the introduction of a sterile-water-only policy for ICUs and other high-risk units may be a more cost-effective approach.

Copper doped polymer shells can provide a very useful diagnostic for fast ignition experiments currently being performed at various laboratories around the world. The low concentration copper dopant acts as an efficient x-ray source providing information on the physics of fast ignition. We have developed copper doped glow discharge (GDP) coatings suitable for such purposes. Copper acetylacetonate (CuAcAC), a solid at room temperature, was used in a heated jacket as the dopant source. We used this technique to fabricate thin ({approx}5-7 {mu}m) GDP shells doped with {approx}1 at % copper through the depolymerizable mandrel process for fast ignition experiments. The details of the experimental set up and the range and limitations of the technique are discussed.

Inertial Confinement Fusion (ICF) shells are mesoscale objects with nano-scale dimensional and nanosurface finish requirements. Currently, the shell dimensions are measured by white-light interferometry and an image analysis method. These two methods complement each other and give a rather complete data set on a single shell. The process is, however, labor intensive. We have developed an automation routine to fully characterize a shell in one shot and perform unattended batch measurement. The method is useful to the ICF program both for production screening and for full characterization. It also has potential for Inertial Fusion Energy (IFE) power plant where half a million shells need to be processed daily.

Structural and optical properties of GaN/AlGaN multiple quantum wells (MQWs) grown by plasma-assisted molecular-beam epitaxy on ( 1 1 0 0 ) plane free-standing GaN substrates and (0 0 0 1) GaN quasi-substrates have been compared. Atomic force microscopy studies indicate that the films and MQW structures grown on both substrates replicate the surface morphology of the substrates. MQWs with AlGaN barriers grown in the presence of In flux have stronger photoluminescence (PL) intensity than those with AlGaN barriers without In. X-ray diffraction spectra of MQWs grown on the (0 0 0 1) GaN substrates show larger number of superlattices peaks than those grown on ( 1 1 0 0 ) substrates suggesting that the former have smoother interfaces. The PL spectra of MQWs deposited on (0 0 0 1) GaN substrates, where the growth is in a polar direction, exhibit a red-shift as well as a decrease in peak intensity with increase in well widths. Similar MQW structures on the ( 1 1 0 0 ) GaN, on which the growth is in a non-polar direction, do not exhibit this phenomenon, which we attribute to the absence of internal electric fields in these structures. PL intensity of MQWs with a well width of 75 A is 20 times stronger for those grown on the ( 1 1 0 0 ) plane than on the (0 0 0 1) plane GaN substrate.

Antibiotic resistance is an increasing threat in hospitals and both morbidity and mortality from infections are greater when caused by drug-resistant organisms. Whilst hospitals are universally blamed for this increase, there is an insufficient appreciation of external sources of resistance, such as when patients are admitted to hospitals from long-term care facilities in the community. The use of antibiotics in family practice and animal husbandry has also been linked to drug resistance being encountered in the hospital setting. Justifiable hospital antibiotic use, which can be life saving, may lead to 'collateral damage' with the emergence of resistance in non-target bacteria in the bowel, for example, with subsequent spread by cross-infection. At a management level, antibiotic resistance can have a significant impact on the ability of hospitals to maintain services since cohorting of patients and ward closures from outbreaks add to continuing bed shortages and waiting lists. Hospital laboratories must review their standard operating procedures since some resistance mechanisms may be missed by current methods of antibiotic susceptibility testing. With increasing public concern from press reports of 'multiresistant Staphylococcus aureus killer virus' and other drug-resistant organisms, there will inevitably be a push by national authorities for more surveillance data on antibiotic resistance; however, the cost-effectiveness of different surveillance strategies should be considered. Clinical governance and risk management are dominant themes in the National Health Service and hospital hygiene and antibiotic resistance are likely to feature prominently in audits related to these themes in the near future.

The purpose of this study was to compare values of maximal accumulated oxygen deficit (MAOD; a measure of anaerobic capacity) and peak post-exercise blood lactate concentration ([lactate]; a reflection of glycolytic contribution) in running and cycling, in women and men.One hundred and nineteen women and 104 men performed an exhaustive treadmill test of ~5 min duration; 106 women and 110 men performed an exhaustive cycle ergometer test of ~5 min duration. Oxygen demands for the exhaustive exercise tests were estimated by extrapolation from steady state VO2 values. For running, an upwardly curvilinear relationship between demand and speed (i.e., with demand a function of speed1.05) was used. For cycling, a linear relationship between demand and work rate was used.The MAOD was 22% higher (P0.01) in running than in cycling, and 32% higher (P0.01) in men than in women. Peak [lactate] was 8% higher (P0.01) in running, and 23% higher (P0.01) in men. The VO2max was 10% higher (P0.01) in running, and 14% higher (P0.01) in men.These results indicate that some of the differences between running and cycling, which affect MAOD, do not similarly affect VO2max or peak [lactate]. It is possible that greater lactate removal by the upper body musculature during running permits the greater anaerobic capacity in running, and explains the relatively small difference in blood [lactate] in running compared to cycling.

The Texas Gulf of Mexico coast is experiencing high (5–11 mm/yr) rates of relative sea level (RSL) rise that are the sum of subsidence and eustatic sea level (ESL) rise. Even higher rates are associated with areas of groundwater pumping from confined aquifers. We investigate the possibility of deep petroleum production as a cause for the high regional rates of subsidence. The northeast Texas coast was chosen for the study because it has a high rate of RSL rise, very limited groundwater production, and a long history of petroleum production. We examine in detail the Big Hill and Fannett fields, for which adequate bottom hole pressure (BHP) and well log data are available. The hypothesis of deep petroleum production is tested in three ways. First, industry BHP tests show many of the fields are depressurized to far below hydrostatic pressures. Second, analysis of BHP data over time in the Big Hill and Fannett fields indicates that some Zones in these fields were below hydrostatic when production commenced. This indicates that depressurization from production in neighboring fields or zones within the same field is not limited to the production zone. Third, three models for subsidence (a general 1-D regional model, an intrareservoir model, and a reservoir bounding layer model), using reasonable hydrogeological parameters, predict subsidence within the inferred range of data. The latter two models use data from the Big Hill and Fannett fields. Additional verification of the hypothesis that deep petroleum production is causing or accelerating regional subsidence will require the collection and analysis of data on the subsurface hydrogeological parameters and detailed measurements of the spatial and temporal distribution of subsidence along the Texas Coast.

Free-standing wafers (50 mm diameter) of GaN were grown by halide vapor phase epitaxy on lattice-matched γ-LiAlO2. We report a transmission electron microscopy study of defects and defect densities in these wafers. The growth direction is [101_0]. Stacking faults in the basal plane are seen when viewing the specimen in the [12_10] direction with an average spacing of less than 100 nm. Convergent beam electron diffraction measurements show no switch in the polarity and thus the faults are proposed to be ABABACAC changes in the stacking. Threading dislocations are found to have a correlated arrangement with a density of 3×108 cm−2 when viewing the [12_10] direction and widely varying (depending upon location) when viewing in the [0001] direction. These dislocations act as “seeds” for postgrowth surface features that directly exhibit the correlated nature of these threading dislocations.

Polarization effects have been studied in GaN/AlGaN multiple quantum wells (MQWs) with different c-axis orientation by means of excitation-dependent photoluminescence (PL) analysis. Quantum structures were grown on [0001]-oriented sapphire substrates (C plane) and single-crystalline [1100]-oriented freestanding GaN (M plane) using the metalorganic chemical vapor deposition technique. Strong PL spectrum line blueshifts (up to 140 meV) which are correlated with the excitation intensity have been obtained for C-plane MQWs, whereas no shift has been observed for M-plane MQWs. Theoretical calculations and comparison with the PL data confirm that the built-in electric field for C-plane structures is much stronger than the field present for M-plane MQWs. In the former case, the excitation-induced blueshift of the PL line is due to the screening of the built-in electric field by photoinjected carriers, which is consistent with the field strength of 1.23 MV/cm in the absence of excitation.

We report homoepitaxial GaN growth on freestanding (1100) oriented (M-plane GaN) substrates using low-pressure metalorganic chemical vapor deposition. Scanning electron microscopy, atomic-force microscopy, and photoluminescence were used to study the influence of growth conditions such as the V/III molar ratio and temperature on the surface morphology and optical properties of the epilayers. Optimized growth conditions led to high quality (1100) oriented GaN epilayers with a smooth surface morphology and strong band-edge emission. These layers also exhibited strong room temperature stimulated emission under high intensity pulsed optical pumping. Since for III-N materials the (1100) crystal orientation is free from piezoelectric or spontaneous polarization electric fields, our work forms the basis for developing high performance III-N optoelectronic devices.

Beginning with a review of early spectrometers, this article describes the essential features common to instruments for spectroscopic and imaging applications. Evolution of spectrometers and spectroscopic techniques have been closely linked, and these are described with particular reference to improvements in magnet technology and the development of Fourier transform methods. The basic elements of the radiofrequency (RF) system are introduced. The development of double resonance methods and, later, multidimensional NMR has added to the functionality and complexity of spectrometers while greater use of digital technology and software has led to ever-increasing versatility. The NMR probe, that couples the RF energy to and from the sample, is the component of the spectrometer that is most specific to different applications. The important factors are described. Other ancillary features of the spectrometer are briefly discussed. Keywords: spectrometer; magnet; spectroscopy; Fourier transform; probe; sensitivity; resolution; homogeneity; shimming; digitization

Summary Isolates from a presumptive nosocomial outbreak of Clostridium difficile infection at a large teaching hospital were typed by pyrolysis mass spectrometry (PMS) and antibiograms. One isolate, from the putative index case, was dissimilar from the outbreak strain, but 24 isolates from 16 patients were indistinguishable by both methods. The outbreak centred on two wards for the acute care of the elderly, with a few cases elsewhere. Transfer of patients appeared to be the route of transmission between wards. There was a significant fall in the incidence of cases following intervention by the Infection Control Unit. This included ward inspection, advice on antibiotic usage and advice on prevention of faecal-oral transfer, particularly by proper handwashing. Subsequent monitoring of C. difficile infection showed a background of sporadic, dissimilar isolates with occasional apparent cross-infection incidents limited to a few patients. In suspected outbreaks, patterns of antibiotic susceptibility may be useful in initial screening, before referral for more sophisticated typing. There was excellent correlation between PMS results, antibiograms and epidemiological information.

Four variations of the least-squares regression procedure proposed by Lettau (1971) were used to define a solution envelope containing the soil thermal diffusivity function, a(z), for a soil with a heterogeneous moisture profile. An explicit finite difference model of the one-dimensional heat equation was used to evaluate the four variations of Lettau’s procedure based upon agreement between measured and simulated temperatures over a 24-h temperature cycle. The application of Lettau’s regression procedure to a database containing only temperature data from the cooling cycle portion of the diurnal temperature wave was shown to most faithfully reproduce field temperature measurements.

We examined the efficacy of 2 commercially available wipes to effectively remove, kill, and prevent the transfer of both methicillin-resistant and methicillin-susceptible Staphylococcus aureus from contaminated surfaces. Although wipes play a role in decreasing the number of pathogenic bacteria from contaminated surfaces, they can potentially transfer bacteria to other surfaces if they are reused.

This study establishes the age-adjusted tolerance intervals for retinal vascular responses to sustained handgrip contraction (a test of sympathetic nerve function). Forty adult subjects (mean age: 39.7 +/- 14.1 years, range: 20 to 72 years; 19 males) were included in the final analysis. Mean percentage calibre change in response to sustained handgrip contraction in this population was -5.61% with a significant correlation between subject age and percentage retinal vessel calibre change (p less than 0.001). Mean retinal arteriolar calibre change in response to systemic autonomic stimulation varied significantly with age: between -8.48% at age 20 years and -2.06% at age 70 years with a mean of -5.95% at the mean age of 39.7 years. The standard deviation is 3.04% and the 95% confidence intervals were set between +/-6.17%. This autoregulatory reflex appears to be inversely related to age.

International audience; AimThis study aimed to test if investigate whether the anaerobic work capacity is replenished while exercising at critical power intensity. Then, a known exercise duration, which demands high anaerobic energy contribution, was compared to intermittent exercise duration with passive and active (cycling at critical power intensity) rest periods.MethodsNine participants performed five sessions of testing. From the 1st to the 3rd sessions, individuals cycled continuously at different workloads (Phigh, Pintermediate and Plow) in order to estimate the critical power and the anaerobic work capacity. The 4th and 5th sessions were performed in order to determine the influence of anaerobic work capacity replenishment on exercise duration. They consisted of manipulating the resting type (passive or active) between two cycling efforts. The total exercise duration was determined by the sum of the two cycling efforts duration.ResultsThe exercise duration under passive resting condition (408.0 ± 42.0 s) was longer (p < 0.05) than known exercise duration at Pintermediate (Tintermediate = 305.8 ± 30.5 s) and than exercise duration performed under active resting conditions (Tactive = 304.4 ± 30.7 s). However, there was no significant difference between Tintermediate and Tactive.ConclusionThese results demonstrated indirect evidence that the anaerobic work capacity is not replenished while exercising at critical power intensity.; ObjectifL’objectif de cette étude est d’examiner si la capacité de travail anaérobie est restaurée lors d’un exercice réalisé à puissance critique. Pour cela, un exercice de durée connue, qui sollicite à un haut niveau la filière anaérobie a été comparé à un exercice intermittent réalisé soit suivant une modalité de récupération passive, soit suivant une modalité de récupération active (à puissance critique).MéthodesNeuf sujets ont participé à cinq sessions de tests. Lors des sessions un à trois, des exercices continus sur ergocycle étaient réalisés à trois puissances différentes (Pélevée, Pintermdiaire et Pfaible), afin de déterminer la puissance critique et la capacité de travail anaérobie. Les sessions quatre et cinq étaient réalisées dans un ordre aléatoire pour identifier l’influence de la restauration de la capacité de travail anaérobie sur le temps d’exercice. Elles se différenciaient suivant l’intensité de la récupération (passive ou active) et consistaient en un exercice de 150 secondes à Pintermédiare, suivi de 300 secondes de récupération et d’un exercice à Pintermédiare poursuivi jusqu’à épuisement.RésultatsDans de la condition de récupération passive (Tpassive = 408,0 ± 42,0 secondes), la durée d’exercice était plus longue (p < 0,05) que lors de l’exercice à Pintermédiare (Tintermédiare = 305,8 ± 42,0 secondes) et lors de l’exercice réalisé avec une récupération active (Tactive = 304,4 ± 30,5 secondes). Il n’y avait pas de différence significative entre Tintermédiaire et Tactive.ConclusionCes résultats montrent de façon indirecte que la capacité de travail anaérobie n’est pas restaurée lors d’un exercice réalisé à puissance critique.

The retinal vessel calibre responses to systemic sympathetic stimulation, were studied in nine patients (eight male; mean age: 31.7 years; range: 19-58 years) with unilateral disruption of their cervical sympathetic tract. All patients had ipsilateral decreased/absent facial sweating and a Horners syndrome, evidence of unilateral sympathetic denervation. Both eyes of each patient were studied and the results were analysed in two groups: the group of nine sympathectomised eyes and the control group of unaffected fellow eyes. During handgrip contraction there was a significant difference in the mean retinal arteriolar constriction (mean +/- SEM) between the group of sympathectomised eyes (4.6 +/- 0.89%) and control eyes (7.1 +/- 1.13%), p less than 0.01. Similarly, there was a significant difference in mean venule constriction during sustained handgrip contraction between the group of sympathectomised eyes (1.5 +/- 0.67%) and control eyes (4.9 +/- 0.98%), p less than 0.05. There was no significant difference in the mean rise in diastolic blood pressure between the two groups: control eyes +27.9 +/- 2.38 mmHg and sympathectomised eyes +27.8 +/- 2.25 mmHg. There was no correlation between the blood pressure and retinal vessel responses in either group. These results suggest that the sympathetic nervous system plays an integral role in retinal blood flow regulation.

The sections in this article are 1 Introduction 2 Historical Review 3 Modern Probe Technology 4 Conclusions 5 Biographical Sketch Related Articles

The running velocities associated to lactate minimum (V(lm)), heart rate deflection (V(HRd)), critical velocity (CV), 3.000 m (V(3000)) and 10 000 m performance (V10km) were compared. Additionally the ability of V(lm) and V(HRd) on identifying sustainable velocities was investigated.Twenty runners (28.5+/-5.9 y) performed 1) 3,000 m running test for V3000; 2) an all-out 500 m sprint followed by 6x800 m incremental bouts with blood lactate ([lac]) measurements for V(lm); 3) a continuous velocity-incremented test with heart rate measurements at each 200 m for V(HRd); 4) participants attempted to 30 min of endurance test both at V(lm)(ETV(lm)) and V(HRd)(ETV(HRd)). Additionally, the distance-time and velocity-1/time relationships produced CV by 2 (500 m and 3 000 m) or 3 predictive trials (500 m, 3,000 m and distance reached before exhaustion during ETV(HRd)), and a 10 km race was recorded for V10km.The CV identified by different methods did not differ to each other. The results (m.min(-1)) revealed that V(lm) (281+/-14.8)CV (292.1+/-17.5)=V10km (291.7+/-19.3)V(HRd) (300.8+/-18.7)=V3000 (304+/-17.5) with high correlation among parameters (P0.001). During ETVlm participants completed 30 min of running while on the ETV(HRd) they lasted only 12.5+/-8.2 min with increasing [lac].We evidenced that CV and Vlm track-protocols are valid for running evaluation and performance prediction and the parameters studied have different significance. The V(lm) reflects the moderate-high intensity domain (below CV), can be sustained without [lac] accumulation and may be used for long-term exercise while the V(HRd)overestimates a running intensity that can be sustained for long-time. Additionally, V3000 and V(HRd) reflect the severe intensity domain (above CV).

VO2peak can be achieved over the range of intensities that define the severe intensity domain. The purpose of this study was to help characterize the VO2 response during constant-load exercise in this domain.Twelve participants performed cycle ergometer tests at 267+/-52 W, 238+/-45 W, and 216+/-37 W, which were individually selected to elicit VO2peak and to cause fatigue in 3 min, 5 min, and 7 min, respectively.Times to fatigue were 201+/-16 s, 301+/-20 s, and 448+/-51 s, respectively. VO2 responded faster at higher work rates, with VO2peak reached after 154+/-25 s, 193+/-35 s, and 206+/-24 s, respectively. Extrapolation of the times to reach VO2peak revealed that 300 W was the highest power, and 151 s was the shortest time, for which VO2peak could be elicited. TheVO2 response was described using a three-component model. Exercise intensity did not affect the speed of the primary response, with time constants of 22+/-3 s, 23+/-4 s, and 23+/-4 s, respectively. However, the size of the primary phase was greater at higher intensities, with amplitudes of 1,798+/-200 mlxmin-1, 1,739+/-267 mlxmin-1, and 1,677+/-254 mlxmin-1, respectively. The amplitude of the slow component was correspondingly smaller at higher intensities. Extrapolation of the slow component amplitudes revealed that 299 W was the highest intensity, and 152(-1)53 s was the shortest time, for which a slow component would be engendered.VO2peak is attained faster at higher intensities because the amplitude of the primary response is greater, not because the response is faster. There is a slow component to the VO2 response at all intensities within the severe domain, but not at higher intensities, in the extreme domain, where fatigue occurs before VO2peak can be elicited.

MRI has been used to measure hindlimb muscle volume in female and male transgenic mice overexpressing the Gly93Ala (G93A) mutant human superoxide dismutase 1 (SOD1), a widely used model of familial amyotrophic lateral sclerosis (FALS), over the first 4 months of life. Significant decreases in the hindlimb muscle volume of the female G93A SOD1 mice were evident from 11 weeks of age, before other overt pathology appeared. By 15 weeks volume had decreased by 37% compared with 7 weeks, from 0.84+/-0.04 cm(3) (mean+/-standard deviation, n = 6) to 0.54+/-0.07 cm(3), (p0.05), despite an increase in body weight of ca. 12% (from 16.2 +/- 1.4 to 18.1 +/- 0.7 g). Female wild-type volume increased by ca. 30% whilst the body weight increased by 15%. Muscle wasteage was less (0.82+/-0.1 to 0.65+/-0.02 cm(3), p0.05, n = 6) in male G93A SOD1 mice between 8 and 16 weeks of age, against a body weight increase trend from 20.7 +/- 0.4 to 21.6 +/- 0.5 g, (p0.05). Wild-type male muscle volume did not change significantly over this period, with an increase in body weight of 20%. Longitudinal MRI hindlimb muscle volume measurements may provide a straightforward, rapid, non-invasive and sensitive, way of monitoring outcome of experimental ALS treatments.

We report the development of large 50 mm diameter free standing wafers of GaN. GaN layers up to 350 /spl mu/m thick have been grown by HVPE on lattice-matched LiAlO/sub 2/ substrates. The original oxide substrates were removed by wet chemical etching, and the defect structure of the GaN wafers has been investigated. The issue of stacking faults vs. polar inversion domains has been resolved in favor of ABABACAC stacking sequences. A UV-emitting LED (368 nm) has been developed on these substrates, using molecular beam epitaxy.