A Series-elastic Robot for Back-pain Rehabilitation

This paper addresses the robot-assisted rehabilitation of back pain, an epidemic health problem affecting a large portion of the population. The design is composed of two springs in series connected to an end-effector via a pair of antagonistic cables. The spring and cable arrangement forms an elastic coupling from the actuator to the output shaft. An input-output torque model of the series-elastic mechanism is established and studied numerically. The study also illustrates the variation of the mechanism’s effective stiffness by changing the springs’ position. In addition, we built a prototype of the robotic mechanism and design experiments with a robotic manipulator to experimentally investigate its dynamic characteristics. The experimental results confirm the predicted elasticity between the input motion and the output torque at the end-effector. We also observe an agreement between the data generated by the torque model and data collected from the experiments. An experiment with a full-scale robot and a human subject is carried out to investigate the human-robot interaction and the mechanism behavior.

     

Bioinformatics

Computational methods are becoming an increasingly important aspect of the evaluation and analysis of experimental data in molecular biology. The use of computational methods towards solving problems in biology is known as bioinformatics. The field of bioinformatics is constantly redefining itself as methods for collecting biological data are developed and refined. While the future directions of the field are impossible to predict, one conclusion seems to be evident: computational techniques have changed the way in which biologists collect and analyze experimental data. Computation will continue to be a prominent component of biochemistry and molecular biology research for the foreseeable future. While early studies developed the techniques necessary to sequence entire genomes, scientists are now investigating the interacting mechanisms that control the expression of genes. Ambitious new efforts are underway to identify the complex biological pathways of interaction between genes, the proteins for which they code, and the various metabolic intermediates acted upon by these proteins. Advances in understanding these sorts of large scale biological problems bear enormous promise for improving the human condition.     

Knowledge discovery in medical and biological datasets using a hybrid Bayes classifier/evolutionary algorithm

A key element of bioinformatics research is the extraction of meaningful information from large experimental data sets. Various approaches, including statistical and graph theoretical methods, data mining, and computational pattern recognition, have been applied to this task with varying degrees of success. Using a novel classifier based on the Bayes discriminant function, we present a hybrid algorithm that employs feature selection and extraction to isolate salient features from large medical and other biological data sets. We have previously shown that a genetic algorithm coupled with a k-nearest-neighbors classifier performs well in extracting information about protein-water binding from X-ray crystallographic protein structure data. The effectiveness of the hybrid EC-Bayes classifier is demonstrated to distinguish the features of this data set that are the most statistically relevant and to weight these features appropriately to aid in the prediction of solvation sites.     

Identification of cantharidin in false blister beetles (Coleoptera,Oedemeridae) from florida

Cantharidin, a potent vesicant and antifeedant, is identified for the first time in two oedemerid beetles from the western hemisphere. Amounts of the substance per beetle were found to range from 2 to 7 g inHeliocis repanda and from 15 to 35 g inOxycopis thoracica. Females had two to three times more cantharidin than males of the same species. Cantharidin loads of these beetles are sufficient to irritate human skin.     

Strain-induced birefringence in vertical-cavity semiconductorlasers

We describe a new technique to study and control the polarization properties of planar vertical-cavity semiconductor lasers. The technique consists of the application of a controllable amount of strain by means of the thermal expansion that results from local heating in the vicinity of the device. Analytical expressions are derived for the strain and birefringence induced with this hot-spot technique. Experimentally, the relation between strain and birefringence is found to be highly anisotropic; this allows a natural interpretation of the distribution of the native polarization angles     

Crossing the interdisciplinary barrier: a baccalaureate computer science option in bioinformatics

Bioinformatics is a new and rapidly evolving discipline that has emerged from the fields of experimental molecular biology and biochemistry, and from the artificial intelligence, database, pattern recognition, and algorithms disciplines of computer science. Largely because of the inherently interdisciplinary nature of bioinformatics research, academia has been slow to respond to strong industry and government demands for trained scientists to develop and apply novel bioinformatic techniques to the rapidly growing freely available repositories of genetic and proteomic data. While some institutions are responding to this demand by establishing graduate programs in bioinformatics, the entrance barriers for these programs are high, largely because of the significant amount of prerequisite knowledge in the disparate fields of biochemistry and computer science required for sophisticated new approaches to the analysis and interpretation of bioinformatics data. The authors present an undergraduate-level bioinformatics curriculum in computer science designed for the baccalaureate student. This program is designed to be tailored easily to the needs and resources of a variety of institutions.     

Direct numerical simulation of auto-ignition of a hydrogen vortex ring reacting with hot air

Direct numerical simulation (DNS) is used to study chemically reacting, laminar vortex rings. A novel, all-Mach number algorithm developed by Doom et al. [J. Doom, Y. Hou, K. Mahesh, J. Comput. Phys. 226 (2007) 1136–1151] is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H₂/air combustion proposed by Mueller et al. [M.A. Mueller, T.J. Kim, R.A. Yetter, F.L. Dryer, Int. J. Chem. Kinet. 31 (1999) 113–125]. Diluted H₂ at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis number and stroke ratio (ratio of piston stroke length to diameter). Results show that auto-ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a ‘most reactive’ mixture fraction, ${\zeta }_{MR}$ (Mastorakos et al. [E. Mastorakos, T.A. Baritaud, T.J. Poinsot, Combust. Flame 109 (1997) 198–223]). Subsequent evolution of the flame is not predicted by ${\zeta }_{MR}$; a most reactive temperature $T_{MR}$ is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke ratios greater than the formation number, ignition initially occurs behind the leading vortex ring, then occurs along the length of the trailing column and propagates toward the ring. Lewis number is seen to affect both the initial ignition as well as subsequent flame evolution significantly. Non-uniform Lewis number simulations provide faster ignition and burnout time but a lower maximum temperature. The fuel rich reacting vortex ring provides the highest maximum temperature and the higher oxidizer temperature provides the fastest ignition time. The fuel lean reacting vortex ring has little effect on the flow and behaves similar to a non-reacting vortex ring.     

Cantharidin production in a blister beetle

A case-control study was carried out in Nottingham Health District, to establish whether children under five years of age admitted to hospital after a accidental injury were more likely to have previously attended the accident and emergency (A & E) department than community controls. The subjects were 342 case-control pairs matched on sex and date of birth, consisting of children under five years resident in the Health District, and the main exposure measures were attendance at the A & E department before the case's first admission, type of injury and number of earlier attendances. It was found that, after adjusting for social deprivation score and proximity to hospital, children who had been admitted after an accidental injury were twice as likely to have attended the A & E department than community controls, and were more likely to have had more than one earlier attendance. Odds ratios were significantly raised for soft-tissue injuries and lacerations. It is concluded that accidental injuries in pre-school children that require attendance at the A & E department predict accidental injuries requiring admission. Making attendances at A & E departments notifiable to health visitors would facilitate the undertaking of accident prevention work.