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Diurnal variations in the hydroxyl radical concentration of ambient air were measured for the first time by the technique of laser-induced fluorescence.

The use of rocker models to understand functional tasks of the human lower limb is attractive because of their simplicity. Recent studies have determined a consistent feature of able-bodied walking termed the roll-over shape (ROS), which is the effective rocker shape that the lower limb system conforms to between initial contact and contralateral initial contact during walking. However, it is unclear what effective rocker shapes are used for fore-aft swaying. A better understanding of these shapes could be used to develop improved prostheses for this task, perhaps improving balance and balance confidence, and reducing the occurrence of falling in lower limb prosthesis users. We measured effective rocker shapes used by eleven able-bodied persons during walking and fore-aft swaying. We hypothesized that the curvature of the swaying shapes would be smaller (radius larger) than that of the walking shapes, providing a more stable interface with the ground during swaying. The radius (measured as the inverse of the curvature of the shape) was found to be about 1/3 of the leg length for walking, but over two times the leg length for swaying. A model examining the effective ankle stiffness necessary to achieve these curvatures suggests that the stiffness of a biomimetic prosthetic ankle would need to be over 3 times higher for fore-aft swaying than for walking. These results suggest that two separate modes would be needed in an ankle-foot prosthesis to mimic the physiologic system for walking and swaying.

Tuberculosis is both highly prevalent across the world and eludes our attempts to control it.The current bacillus Calmette-Guérin vaccine has unreliable protection against adult pulmonary tuberculosis. As a result, tuberculosis vaccine development has been an ongoing area of research for several decades. Only recently have research efforts resulted in the development of several vaccine candidates that are further along in clinical trials. The majority of the barriers surrounding tuberculosis vaccine development are related to the lack of defined biomarkers for tuberculosis protective immunity and the lack of understanding of the complex interactions between the host and pathogen in the human immune system. As a result, testing various antigens discovered through molecular biology techniques have been only with surrogates of protection and do not accurately predict protective immunity. This review will address new discoveries in latency antigens and new next-generation candidate vaccines that promise the possibility of sterile eradication. Also discussed are the potentially important roles of systems biology and vaccinomics in shortening development of an efficacious tuberculosis vaccine through utilization of high-throughput technology, computer modelling and integrative approaches.

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Recent studies have determined a seemingly consistent feature of able-bodied level ground walking termed the roll-over shape, which is the effective rocker (cam) shape that the lower limb system conforms to between heel contact and contralateral heel contact during walking (first half of the gait cycle). The roll-over shape has been found to be largely unaffected by changes in walking speed, load carriage, and shoe heel height. However, it is unclear from previous studies whether persons are controlling their lower limb systems to maintain a consistent roll-over shape or whether this finding is a byproduct of their attempt to keep ankle kinematic patterns similar during the first half of the gait cycle. We measured the ankle-foot roll-over shapes and ankle kinematics of eleven able-bodied subjects while walking on rocker shoes of different radii. We hypothesized that the ankle flexion patterns during single support would change to maintain a similar roll-over shape. We also hypothesized that with decreasing rocker shoe radii, the difference in ankle flexion between the end and beginning of single support would decrease. Our results supported these hypotheses. Ankle kinematics were changed significantly during walking with the different rocker shoe radii (p < 0.001), while ankle-foot roll-over shape radii (p = 0.146) and fore-aft position (p = 0.132) were not significantly affected. The results of this study have direct implications for designers of ankle-foot prostheses, orthoses, walking casts/boots, and rocker shoes. The results may also be relevant to researchers studying control of human movements.

Indices on MRI scan post hip spica cast placement can be measured reliably, assessing acetabular geometry, degree of hip reduction and barriers to reduction.

We report the first measurement of hydroxyl (OH) concentrations in air by detecting the resonance fluorescence excited by tunable radiation near 2825.8 A, On a particular day, the OH concentrations deduced from these measurements ranged from a high of 1.5x lo 8 OH/cm 3 in the early afternoon to a level below 5x lo 6 OH/cm 3 at night. This Letter reports the first measurement of hydroxyl (OH) concentrations in air by detecting the resonance fluorescence excited by a tunable laser source in the ultraviolet. 1 Weinstock 2 has pointed out that OH plays a central role in smog formation and in controlling the global concentrations of carbon monoxide and methane. The ability to measure ambient concentrations of OH should afford an accurate determination of numerous photochemical cycles operative in either polluted or natural atmosphere. However, the ambient concentration of OH has never been established experimentally, and various estimates 2,3 yield results ranging from 7xl0 4 to 5xl0 8 OH/ cm 3 .In performing the experiments in the laboratory, it was observed that the OH concentration in air varied during the course of the day. On a particular day, it ranged from a value of 1.5xl0 8 OH/cm 3 in the early afternoon (-2:00 p.m.), to 1.6xio 7 OH/cm 3 at around 6:00 p.m., and to a level below our present detection limit of 5xl0 6 OH/cm 3 (0.2 part per 10 12 in air) at night (-10:30 p.m.). The OH concentration also dropped to a level below the detection limit when it was raining or overcast outside, or when the ventilation system was shut off to prevent the fresh air outside from getting into the laboratory. It was estimated that a significant portion of the air near the focal region came from outside the laboratory with a transport time of about 6 sec. We are currently improving the collection efficiency of our optics by a factor of 10, and expect to monitor the diurnal variation of OH concentration in air both inside the laboratory and outside.The experiments were performed with a tunable source near the P x (2) line (2825.8 A) in the 2 n (v = 0) -2 S + (v = 1) transitions 4 of OH. The light source near 2825.8 A was derived from the second harmonic of the output from a dye laser system; the latter consisted of one oscillator and two amplifier stages, 5 and were operated with rhodamine S dissolved in methanol and at a rep-etition rate of one pulse every 10 sec. Frequency narrowing was accomplished using a Littrow grating as an end reflector and an intracavity Fabry-Perot etalon. Fine tuning was done by varying the mixture of helium and propylene which filled the etalon spacing. The output pulse from the laser typically measured 50 mJ in energy and 0.4 cm" 1 in spectral width, and lasted about 0.5 (Jsec. The second harmonic of the output was generated in a 5-cm crystal of ammonium dihydrogen phosphate oriented for index matching. With optimal focusing, an output energy of up to 6 mJ per pulse at the second harmonic frequency was obtained. Figure 1 depicts a schematic of the experimental setup. The second harmonic beam near ...