Miniature in vivo robots for remote and harsh environments

Long-term human space exploration will require contingencies for emergency medical procedures including some capability to perform surgery. The ability to perform minimally invasive surgery (MIS) would be an important capability. The use of small incisions reduces surgical risk, but also eliminates the ability of the surgeon to view and touch the surgical environment directly. Robotic surgery, or telerobotic surgery, may provide emergency surgical care in remote or harsh environments such as space flight, or extremely forward environments such as battlefields. However, because current surgical robots are large and require extensive support personnel, their implementation has remained limited in forward environments, and they would be difficult, or impossible, to use in space flight or on battlefields. This paper presents experimental analysis of miniature fixed-base and mobile in vivo robots to support MIS surgery in remote and harsh environments. The objective is to develop wireless imaging and task-assisting robots that can be placed inside the abdominal cavity during surgery. Such robots will provide surgical task assistance and enable an on-site or remote surgeon to view the surgical environment from multiple angles. This approach is applicable to long-duration space flight, battlefield situations, and for traditional medical centers and other remote surgical locations.     

Epilactose production by 2 cellobiose 2-epimerases in natural milk

It was reported recently that cellobiose 2-epimerases (CE) from various aerobic microorganisms convert lactose to epilactose in defined buffer systems. In this study, we showed that CE from 2 mesophilic microorganisms, Flavobacterium johnsoniae and Pedobacter heparinus, were capable of converting lactose to prebiotic epilactose not only in buffer but also in a complex milk system. First, the 2 enzymes were separately cloned, recombinantly expressed in Escherichia coli, and purified by column chromatography. The production of F. johnsoniae CE was carried out in a stirred-tank reactor, indicating that future upscaling is possible. The bioconversions of milk lactose were carried out at an industrially relevant low temperature of 8°C to avoid undesired microbial contaminations or chemical side reactions. Both enzymes were reasonably active at this low temperature, because of their origin from mesophilic organisms. The enzymes showed different operational stabilities over a 24-h time-course. A conversion yield of about 30 to 33% epilactose was achieved with both enzymes. No side products were detected other than epilactose. Therefore, CE may introduce an added value for particular dairy products by in situ production of the prebiotic sugar epilactose.     

Etched mirror and groove-coupled GaInAsP/InP laser devices for integrated optics

Recent advances in wet and dry etching techniques for GaInAsP/InP laser structures allow the reproducible fabrication of planar and vertical walled facets and grooves. These elements provide efficient mirrors and interstage couplers that may provide the basis for a new generation of monolithic integrated optical devices. Initial experimental results on etched facet lasers and groove-coupled two-section lasers verify theoretical expectations.     

Generation of single-longitudinal-mode subnanosecond light pulses by high-speed current modulation of monolithic two-section semiconductor lasers

The spectral behaviour of monolithic two-section GaInAsP/InP lasers is studied. Single-longitudinal-mode light pulses of less than 750 ps length are produced by driving the long section of the laser only or by prebiasing the long cavity and modulating the short section with a current pulse of 1 ns halfwidth. The wavelength of the output light can be changed by varying the operation temperature or the prebias level.     

Dosimetry fundamentals of endovascular therapy using Re-188 for the prevention of restenosis after angioplasty]

This study investigated whether self-esteem precedes various academic behaviors and beliefs among 593 high school students (63.7% female, 60.9% African American). Measures of home and school self-esteem, grade point average, perceived academic standing and progress, and educational plans were collected by survey and archival review of grade and attendance records at the beginning (pre-test) and end of the school year (post-test). Self-esteem and academic variables differed by gender, race, and guardianship. Self-esteem related significantly to academics and absenteeism. Results suggest selected academic variables predict self-esteem even when the effects of gender, race, and guardianship are removed and pretest self-esteem scores are controlled. In conclusion, student academic performance influences subsequent academic and home self-esteem. Creation of positive academic experiences for youth may be a critical activity, since experts contend that low self-esteem is associated with subsequent behavioral problems. The markedly lower self-esteem of Native American and Hispanic youth warrants further investigation.     

Hydrodynamic Instabilities in Well-Balanced Finite Volume Schemes for Frictional Shallow Water Equations. The Kinematic Wave Case

We report the developments of hydrodynamic instabilities in several well-balanced finite volume schemes that are observed during the computation of the temporal evolution of an out-balance flow which is essentially a kinematic wave. The numerical simulations are based on the one-dimensional shallow-water equations for a uniformly sloping bed with hydraulic resistance. Subsequently, we highlight the need of low dissipative high-order well-balanced filter schemes for non-equilibrium flows with variable cut-off wavenumber to compute the out-balance flow under consideration, i.e. the kinematic wave.     

Crystallographic facets chemically etched in GaInAsP/InP for integrated optics

Vertical crystallographic (011) planes were exposed on (100) GaInAsP/InP double heterostructures (DH) by a newly developed chemical etchant and method. This method provides optically flat, mirror quality facets reproducibly and could be very attractive in integrated optics and optoelectronic devices.     

Low-resistance ohmic contacts to p-InP

A new method for making low-resistance ohmic contacts to p-InP is described. Using layer-by-layer evaporated Au-Zn (25 wt% net Zn)/Cr/Au metallisation, specific contact resistance as low as 4.5 × 10?5 ?cm2 was obtained for p-InP with carrier concentration 2 × 1018 cm?3. The effects of annealing temperature and time on the contact resistances were investigated.