Validity of gait parameters for hip flexor contracture in patients with cerebral palsy

Background: Psoas contracture is known to cause abnormal hip motion in patients with cerebral palsy. The authors investigated the clinical relevance of hip kinematic and kinetic parameters, and 3D modeled psoas length in terms of discriminant validty, convergent validity, and responsiveness. Methods: Twenty-four patients with cerebral palsy (mean age 6.9 years) and 28 normal children (mean age 7.6 years) were included. Kinematic and kinetic data were obtained by three dimensional gait analysis, and psoas lengths were determined using a musculoskeletal modeling technique. Validity of the hip parameters were evaluated. Results: In discriminant validity, maximum psoas length (effect size r = 0.740), maximum pelvic tilt (0.710), maximum hip flexion in late swing (0.728), maximum hip extension in stance (0.743), and hip flexor index (0.792) showed favorable discriminant ability between the normal controls and the patients. In convergent validity, maximum psoas length was not significantly correlated with maximum hip extension in stance in control group whereas it was correlated with maximum hip extension in stance (r = -0.933, p < 0.001) in the patients group. In responsiveness, maximum pelvic tilt (p = 0.008), maximum hip extension in stance (p = 0.001), maximum psoas length (p < 0.001), and hip flexor index (p < 0.001) showed significant improvement post-operatively. Conclusions: Maximum pelvic tilt, maximum psoas length, hip flexor index, and maximum hip extension in stance were found to be clinically relevant parameters in evaluating hip flexor contracture.Y

Highly sensitive CO sensors based on cross-linked TiO2 hollow hemispheres

We report the fabrication of a highly sensitive gas sensor based on a network of nanostructured TiO2 hollow hemispheres (NTHH). O-2 plasma etching induces cross-linking of hexagonal-close-packed polystyrene array, which is adopted as a template substrate for room-temperature deposition of TiO2 thin film. High-temperature calcination effectively removes polystyrene template beads and promotes crystallization of TiO2, finally producing cross-linked NTHH via nanobridges. The gas-sensing capability of a NTHH-based sensor is demonstrated using 1-500 ppm CO. Our sensor exhibits a very high response of 4220% change in resistance when exposed to 500 ppm CO at 250 degrees C, whereas a gas sensor based on a plain TiO2 film shows a 195% change. The high sensitivity of the NTHH-based sensor is attributed to the enhanced gas sensing performance of the narrow nanobridges between hollow hemispheres.close302

Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors

One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with similar to 90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence.X116257sciescopu