MPEG-2 over ATM for video dial tone networks: issues and strategies

Market growth for PC multimedia and digital video owes largely to the rapid adoption of ISO compression standards by the industry. For video dial tone (VDT) services, the MPEG-2 set of standards have clearly emerged as the preferred coding method for VDT networks. For point-to-point switched video or multimedia connections, ATM has emerged as the technology of choice for switching and transport. This article describes how compressed digital video is transported over a VDT network, what some of the issues are, and how they are being addressed by the industry. It describes a generic VDT reference architecture, and the delivery method of video and multimedia information over such a network     

Real-time gait event detection for paraplegic FES walking

A real-time method for the detection of gait events that occur during the electrically stimulated locomotion of paraplegic subjects is described. It consists of a two-level algorithm for the processing of sensor signals and the determination of gait event times. Sensor signals and information about the progression of the stimulator though its pre-specified stimulation “pattern” are processed by a machine intelligence (fuzzy logic) algorithm to determine an initial estimate of the patient's current phase of gait. This is then reviewed and modified by a second algorithm that removes spurious gait estimates, and determines gait event times. These gait event times are known to the system within approximately one-half of a gait cycle. The resulting gait event detection system was successfully evaluated on three subjects. Detection accuracy is not adversely affected by day-to-day gait variability. This work resolved technical and practical issues that previously limited the real time application of these methods. In particular, cosmetically acceptable insole force transducers were used. This gait event detector is designed for use in a real time controller for the automatic adjustment of the intensity and timing of stimulation while the subject is walking using functional electrical stimulation     

Effects of humidity and temperature on in vitro dissolution of carbamazepine tablets

The rate and extent of dissolution of various approved marketed carbamazepine (CBZ) tablets exposed to 33, 52, 75, and 97% relative humidities at both room temperature and 40 degrees C, and saturated water vapor at room temperature were compared to fresh unstressed tablets. The dissolution data indicate that exposure of CBZ tablets to high humidity and temperature can have a profound effect on tablet disintegration and dissolution. The dissolution rates of some batches of CBZ products exposed to 97% humidity at 40 degrees C or saturated water vapor at room temperature were drastically reduced in only 6-7 days.     

High-temperature refractory metal-intermetallic composites

In this article, toughness, oxidation, and rupture behaviors of present-generation refractory metal-intermetallic composites are compared to the performance requisites necessary to make these materials a competitive choice for the jet engine turbine environment of the future.     

Copper-containing glass polyalkenoate cements based on SiO<Subscript>2</Subscript>–ZnO–CaO–SrO–P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses: glass characterization,physical and antibacterial properties

A series of copper (Cu)-containing glasses were synthesized and incorporated into a SiO₂–ZnO–CaO–SrO–P₂O₅-based glass system. Additions of 6 and 12 mol% CuO retained the amorphous character, and glasses were processed to possess similar particle sizes and surface areas. Glass characterization using X-ray photoelectron spectroscopy and magic angle spinning nuclear magnetic resonance determined that the addition of 12 mol% CuO increased the fraction of Q⁴-speciation and the concentration of bridging oxygens. Each glass presented solubility profiles for the release of Si⁴⁺ (18–31 mg/L), Ca²⁺ (13–16 mg/L), Zn²⁺ (<3 mg/L) and Sr²⁺(2–10 mg/L); however, no Cu²⁺ or P⁵⁺ were released. Cu-GPCs were formulated, and the working time (T _w) and setting times (T _s) were found to be dependent on both polyacrylic acid concentration and CuO addition. The mechanical properties, i.e. the compressive strength (18–30 MPa) and the adhesive bond strength (0.79–1.32 MPa), were relative low which is likely due to the glass structure. Antibacterial properties were evaluated in E. coli (4 mm), S. epidermidis (10 mm), S. aureus (UMAS-1) and vancomycin resistant S. aureus (2 mm) and presented antibacterial effects in each microbe tested.     

Potential availability of transplantable organs according to factors associated with type of injury event.

Potential availability of transplantable organs from different types of injury fatalities was studied. Factors examined included target organ damage or disease, age of potential donor, duration of survival before circulatory arrest, and universal rejection factors such as sepsis, HIV infection, or systemic malignancy. Motor vehicle fatalities yielded the greatest proportion of potentially viable organs. Delay in discovery and universal rejection factors were important exclusionary issues for fatalities from suicide, homicide, and non-motor vehicle unintentional injury. There was no difference in organ damage or in duration of survival with higher speeds in fatal crashes, suggesting that states with 65 mph speed limits--and consequently higher death rates--may have greater potential availability of donatable organs than do those with 55 mph maximum. The increase in deaths at higher speeds, however, vastly outweighs the benefits of any possible increase in the potential for donor organs.     

In Vitro Topographical Characterization as a Predictor of in Vivo Controlled Release Quinidine Gluconate Bioavailability

The pH dissolution profiles and bioavailability data of six quinidine gluconate controlled release products were obtained, and attempts were made to identify a dissolution condition that is most indicative of in vivo bioavailability. This was achieved by graphically displaying the pH dissolution profiles of the six products in multi-dimensional graphs utilizing a topographical plotting technique. These graphs were found to be quite effective in illustrating: a) the effects of pH and buffer composition on the dissolution rate of the test products, and b) the in vitro condition that best correlates with in vivo data. It was found that for the quinidine gluconate controlled release dosage forms studied, dissolution carried out in pH 5.4 phosphate buffer was most meaningful in showing the differences among dosage forms and for predicting in vivo bioavailability