Supermedia-enhanced Internet-based telerobotics

This paper introduces new planning and control methods for supermedia-enhanced real-time telerobotic operations via the Internet. Supermedia is the collection of video, audio, haptic information, temperature, and other sensory feedback. However, when the communication medium used, such as the Internet, introduces random communication time delay, several challenges and difficulties arise. Most importantly, random communication delay causes instability, loss of transparency, and desynchronization in real-time closed-loop telerobotic systems. Due to the complexity and diversity of such systems, the first challenge is to develop a general and efficient modeling and analysis tool. This paper proposes the use of Petri net modeling to capture the concurrency and complexity of Internet-based teleoperation. Combined with the event-based planning and control method, it also provides an efficient analysis and design tool to study the stability, transparency, and synchronization of such systems. In addition, the concepts of event transparency and event synchronization are introduced and analyzed. This modeling and control method has been applied to the design of several supermedia-enhanced Internet-based telerobotic systems, including the bilateral control of mobile robots and mobile manipulators. These systems have been experimentally implemented in three sites test bed consisting of robotic laboratories in the USA, Hong Kong, and Japan. The experimental results have verified the theoretical development and further demonstrated the stability, event transparency, and event synchronization of the systems.     

Enterococcal bacteremia in a medical center

BACKGROUND: The enterococci have become important nosocomial pathogens. They can cause multiple site infections and enterococcal bacteremia becomes more frequently associated with a high mortality rate. Previous studies of enterococcal bacteremia showed a variety of results. To establish the significance and importance of enterococci as nosocomial pathogens in this hospital, to characterize their clinical pictures and to search for the risk factors for mortality, this retrospective study was performed. METHODS: There were 208 cases of enterococcal bacteremia which occurred from 1988 to 1992. Twenty-seven cases had no medical charts, dismissing possibility of evaluation. Finally, 181 cases of enterococcal bacteremia were analysed. RESULTS: One hundred and eighteen episodes were nosocomial infections. Polymicrobial bacteremia occurred in 68.5% of the patients and the most common co-isolate was Pseudomonas aeruginosa. Those patients (78.5%) with underlying diseases and malignancies were the most common underlying problems. The portal of entry could be found in 69.6 percent of patients, with the gastrointestinal tract the most common sources. Antimicrobial susceptibility testing showed high gentamicin resistance rate (89.5%), and ampicillin still had about 80 percent sensitivity rate. The group who received specific antibiotic therapy for enterococcus showed lower mortality (36.4% versus 47.6%). Only one case had infective endocarditis. Forty-nine patients suffered from septic shock, the cause of 30 deaths. Totally 75 patients died during hospitalization. Besides sepsis, another major cause of death was their underlying diseases itself. CONCLUSIONS: Enterococci have no doubt become important nosocomial pathogens and enterococcal bacteremia were associated with high mortality, especially in elderly patients with underlying diseases such as malignancy or diabetes. When clinically dealing with sepsis from the gastrointestinal or biliary tract, especially when previous cephalosporins therapy showed no response, the possibility of enterococcal bacteremia should always be considered.     

Wortmannin enhances CPP32-like activity during neuronal differentiation of P19 embryonal carcinoma cells induced by retinoic acid

P19 EC cells undergoes apoptosis during neuronal differentiation induced by retinoic acid. Two CPP32-like proteases, CPP32 and Mch-3, are expressed in untreated and retinoic acid-treated P19 EC cells. CPP32-like activity is remarkably increased in apoptosis during neuronal differentiation of P19 EC cells. Inhibition of CPP32-like proteases prevents apoptosis, suggesting that activation of CPP32-like proteases play central roles in the apoptosis during neuronal differentiation of P19 EC cells. Wortmannin, PI-3K inhibitor, enhances the CPP32-like activity of the retinoic acid-treated P19 EC cells. PI-3K may be involved in the apoptosis during neuronal differentiation as negative regulator.     

Effects of sinus surgery on speech

The human 4 hour patch test provides an opportunity to identify substances with significant skin irritation potential without recourse to the use of animals. The protocol is designed to avoid the production of more than mild irritant reactions and meets the highest ethical standards. This paper provides the background to the development of the method and comments on its performance in the light of recent intra- and inter-laboratory investigations. In particular, the value of the method in providing 'gold standard' data for the identification of those substances (or preparations) which should, or should not, be classified as irritant to skin in European legislation is discussed. On the basis of the published data and supplementary investigations, recommendations are made on both the conduct and interpretation of the human 4 hour patch test. Finally, the lack of any necessity for formal validation of this assay is addressed.     

Biodegradation of chlorpyrifos by either single or combined cultures of some soilborne plant pathogenic fungi

Biodegradation of chlorpyrifos was studied in liquid culture media amended with either single or combined eight different plant pathogenic fungi isolated from the continuous cropping wheat fields. The average recovery of chlorpyrifos from the liquid media was found to be 86.1%. The detection limit of chlorpyrifos by the analytical method used was 19 ppb. Data showed that the growth of mixed fungi at concentrations up to 200 ppm of chlorpyrifos was higher than in the control treatment. Chlorpyrifos concentrations declined in the medium of combined fungi more than it did in the medium of any single fungus with increase in the incubation period. The amount of chlorpyrifos recovered was 79.8 ppm (39.9%) in the combined fungal cultures after 21 days. However, those recovered from the media of Fusarium graminearum, F. oxysporum, Rhizoctonia solani, Cladosporium cladosporiodes, Cephalosporium sp., Trichoderma viridi, Alternaria alternata, and Cladorrhinum brunnescens, ranged from 48.0 to 74.8%. The half-life value (T1/2) for chlorpyrifos was 15.8 day in the medium amended with mixed fungi. However, for the single cultures it ranged from 19.3 to 33.0 day.     

Association of INAD with NORPA is essential for controlled activation and deactivation of Drosophila phototransduction in vivo

Visual transduction in Drosophila is a G protein-coupled phospholipase C-mediated process that leads to depolarization via activation of the transient receptor potential (TRP) calcium channel. Inactivation-no-afterpotential D (INAD) is an adaptor protein containing PDZ domains known to interact with TRP. Immunoprecipitation studies indicate that INAD also binds to eye-specific protein kinase C and the phospholipase C, no-receptor-potential A (NORPA). By overlay assay and site-directed mutagenesis we have defined the essential elements of the NORPA-INAD association and identified three critical residues in the C-terminal tail of NORPA that are required for the interaction. These residues, Phe-Cys-Ala, constitute a novel binding motif distinct from the sequences recognized by the PDZ domain in INAD. To evaluate the functional significance of the INAD-NORPA association in vivo, we generated transgenic flies expressing a modified NORPA, NORPAC1094S, that lacks the INAD interaction. The transgenic animals display a unique electroretinogram phenotype characterized by slow activation and prolonged deactivation. Double mutant analysis suggests a possible inaccessibility of eye-specific protein kinase C to NORPAC1094S, undermining the observed defective deactivation, and that delayed activation may similarly result from NORPAC1094S being unable to localize in close proximity to the TRP channel. We conclude that INAD acts as a scaffold protein that facilitates NORPA-TRP interactions required for gating of the TRP channel in photoreceptor cells.     

Anaplastic large cell lymphoma of T-cell phenotype in acquired immunodeficiency syndrome

A variety of shortcomings are associated with most currently used gastrointestinal contrast agents for magnetic resonance imaging (MRI). Artifacts resulting from peristalsis and other motions in the abdominal region are produced by many positive contrast agents (which increase signal intensity). Although this is not a problem for negative contrast agents (which decrease signal intensity), some negative contrast agents produce magnetic susceptibility artifacts that are especially pronounced at high field strength and with gradient echo pulse sequences. These susceptibility artifacts are produced by both paramagnetic and diamagnetic agents. It has been demonstrated in phantoms, however, that susceptibility matching can be used to produce contrast agents with desirable relaxation and contrast properties but without deleterious susceptibility artifacts. We now report results of animal tests of such an oral contrast agent, consisting of a suspension of superparamagnetic iron oxide particles and diamagnetic barium sulfate particles, compared to individual suspensions of the iron oxide and of the barium sulfate. Iron oxide was the least effective and the matched susceptibility mixture was the most effective for the intestine, which has traditionally been the most difficult region of the GI tract to visualize clearly. Matched susceptibility mixtures, which are inherently able to yield images free of susceptibility artifacts without compromising contrast, show promise of being improved oral negative contrast agents for use in gastrointestinal MRI.     

The D2 autoreceptor agonists SND 919 and PD 128483 decrease stereotypy in developing rats

Although stereotyped behavior in adult rats is partly regulated by dopamine (DA) D2 autoreceptors, previous attempts to demonstrate D2 autoreceptor regulation of stereotypy in developing rats have been unsuccessful. In the present study, two highly selective D2 autoreceptor agonists were used to demonstrate D2 autoreceptor regulation of spontaneous stereotyped behavior in developing rats. Both SND 919 and PD 128483 produced significant dose-dependent decreases in the stereotypy counts of 21-day-old, 35-day-old, and adult rats. There was a 51% decrease in the stereotypy counts of 21-day-old rats injected with SND 919, 0.05 mg/kg, compared to a 36% decrease in the counts of rats pretreated with haloperidol. Similarly, PD 128483 significantly decreased the stereotypy counts of 21-, 35-day-old, and adult rats in a dose-dependent fashion. There was a 58% decrease in the stereotypy counts of 21-day-old rats injected with PD 128483, 0.1 mg/kg, compared to a 17% decrease in counts when the rats were first treated with haloperidol. The effect of haloperidol plus PD 128483 was significantly different from the effect of PD 128483 alone. Injection of SND 919 or PD 128483 had no significant effects on the stereotypy counts of 10-day-old rats. The results suggest that DA D2 autoreceptor-mediated regulation of spontaneous stereotyped behavior is functional at 21, but not 10, days of age.     

Tc trend in high-Tc superconductors

In our previous works, we have shown that most existing ceramic superconductors can be considered to be built of superconductor-semiconductor composite and we have estimated the change in phonon spectrum of the intrinsic superconductor unit if a semiconductor unit is attached to it. Moreover, the proximity effect under the size quantization condition has been examined in the superconductor-semiconductor composite. Each of the stated effects by itself could causeT _c enhancement in general as more semiconductor blocks are added to the system. We extend our study in this paper to analyze the combined actions of phonon spectral change and proximity effect without size quantization condition onT _c variation in members of the Tl₁ series of high-T _c superconductors. Our results indicate that an optimumT _c is obtained if the stated effects are included in the idealized unit cells of the superconductors made up of a superconductor-semiconductor array.