Solid state NMR investigations of biological membrane structures

Issued as Final report, Project no. G-41-63

Flexible parylene-based 3-D coiled cable

Prosthesis systems require reliable and flexible connecting cables from the sensing/stimulating electrode sites to processing circuitries. However, the limitations on the fabrication materials and processes restrict the cables' ability to stretch, resulting in breakage and failure of the implanted cabled device. Thus, a microfabricated and fully implantable 3-D parylene coiled cable for prosthesis application is presented. Compared to traditional flexible cables, this parylene coiled structure is able to be stretched by 100% of its original length and is also long-term biocompatible. In addition, the cable structure can be heat-formed in a mold to match muscle curvature and sharp turns in testing subjects and can also be directly integrated with flexible multi-electrodes arrays and neural probes

IC-integrated flexible shear-stress sensor skin

This paper reports the successful development of the first IC-integrated flexible MEMS shear-stress sensor skin. The sensor skin is 1 cm wide, 2 cm long, and 70 /spl mu/m thick. It contains 16 shear-stress sensors, which are arranged in a 1-D array, with on-skin sensor bias, signal-conditioning, and multiplexing circuitry. We further demonstrated the application of the sensor skin by packaging it on a semicylindrical aluminum block and testing it in a subsonic wind tunnel. In our experiment, the sensor skin has successfully identified both the leading-edge flow separation and stagnation points with the on-skin circuitry. The integration of IC with MEMS sensor skin has significantly simplified implementation procedures and improved system reliability

MECHANISM OF LEG STIFFNESS ADJUSTMENT FOR CHILDREN LANDING ON SURFACES OF DIFFERENT STIFFNESSES

According to the papers, humans do adjust their leg stiffness to accommodate changes in stride frequency or surface stiffness, while hopping in places or running forward. The purpose of this study was to determine the mechanism by which humans adjust leg stiffness during drop landing on surfaces of different stiffness. Kinematic and kinetic data were acquired simultaneously, and then the Inverse Dynamics method was used to acquire the horizontal forces, vertical forces, and the net muscle joint moments in the three lower extremity joints. The quantitative results of the present study might generate more knowledge about the motor performance and the importance of landing to be considered while teaching, coaching and training children

Facial Expression Recognition Using New Feature Extraction Algorithm

This paper proposes a method for facial expression recognition. Facial feature vectors are generated from keypoint descriptors using Speeded-Up Robust Features. Each facial feature vector is then normalized and next the probability density function descriptor is generated. The distance between two probability density function descriptors is calculated using Kullback Leibler divergence. Mathematical equation is employed to select certain practicable probability density function descriptors for each grid, which are used as the initial classification. Subsequently, the corresponding weight of the class for each grid is determined using a weighted majority voting classifier. The class with the largest weight is output as the recognition result. The proposed method shows excellent performance when applied to the Japanese Female Facial Expression database

The catalytic domain of human hepatitis delta virus RNA A proton nuclear magnetic resonance study

AbstractWe have obtained and analyzed the 600 MHz proton NMR spectra of a 74-mer RNA derived from the catalytic domain of hepatitis delta virus genomic RNA (HDV RNA) to determine its secondary structure. Deconvolution of the NMR spectrum obtained at 32°C indicates that part of the 74-mer RNA molecule may exist in multiple conformations in equilibrium. The major conformer contains two A-U base pairs and 14 ± 2 G-C base pairs. It appears to contain no standard G-U base pairs. Our NMR melting study suggests that this conformer has at least two stem-loop regions. One of the regions has been identified to be a tetra-loop. We have assigned five imino proton resonances of the tetraloop stem. Our data is consistent with the pseudoknot model of Perrotta and Been

A micro-electro-mechanical-system-based thermal shear-stress sensor with self-frequency compensation

By applying the micro-electro-mechanical-system (MEMS) fabrication technology, we developed a micro-thermal sensor to measure surface shear stress. The heat transfer from a polysilicon heater depends on the normal velocity gradient and thus provides the surface shear stress. However, the sensitivity of the shear-stress measurements in air is less than desirable due to the low heat capacity of air. A unique feature of this micro-sensor is that the heating element, a film 1 µm thick, is separated from the substrate by a vacuum cavity 2 µm thick. The vacuum cavity prevents the conduction of heat to the substrate and therefore improves the sensitivity by an order of magnitude. Owing to the low thermal inertia of the miniature sensing element, this shear-stress micro-sensor can provide instantaneous measurements of small-scale turbulence. Furthermore, MEMS technology allows us make multiple sensors on a single chip so that we can perform distributed measurements. In this study, we use multiple polysilicon sensor elements to improve the dynamic performance of the sensor itself. It is demonstrated that the frequency-response range of a constant-current sensor can be extended from the order of 100 Hz to 100 kHz