An 802.11 n wireless local area network transmission scheme for wireless telemedicine applications

In this paper, an 802.11 n transmission scheme is proposed for wireless telemedicine applications. IEEE 802.11n standards, a power assignment strategy, space-time block coding (STBC), and an object composition Petri net (OCPN) model are adopted. With the proposed wireless system, G.729 audio bit streams, Joint Photographic Experts Group 2000 (JPEG 2000) clinical images, and Moving Picture Experts Group 4 (MPEG-4) video bit streams achieve a transmission bit error rate (BER) of 10-7, 10-4, and 103 simultaneously. The proposed system meets the requirements prescribed for wireless telemedicine applications. An essential feature of this proposed transmission scheme is that clinical information that requires a high quality of service (QoS) is transmitted at a high power transmission rate with significant error protection. For maximizing resource utilization and minimizing the total transmission power, STBC and adaptive modulation techniques are used in the proposed 802.11 n wireless telemedicine system. Further, low power, direct mapping (DM), low-error protection scheme, and high-level modulation are adopted for messages that can tolerate a high BER. With the proposed transmission scheme, the required reliability of communication can be achieved. Our simulation results have shown that the proposed 802.11 n transmission scheme can be used for developing effective wireless telemedicine systems.

Measurement of direct photon emission in K+-->pi(+)pi(0)gamma decay

We have performed a measurement of the K+-->pi(+)pi(0)gamma decay and have observed 2x10(4) events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7+/-0.8+/-0. 3)x10(-6) in the pi(+) kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.

Measurement of structure-dependent K+ --> &mgr;(+)nu(&mgr;)gamma decay

We report the first measurement of a structure-dependent component in the decay K+-->&mgr;(+)nu(&mgr;)gamma. Using the kinematic region where the muon kinetic energy is greater than 137 MeV and the photon energy is greater than 90 MeV, we find that the absolute value of the sum of the vector and axial-vector form factors is |F(V)+F(A)| = 0.165+/-0.007+/-0.011. This corresponds to a branching ratio of B(SD+) = (1.33+/-0.12+/-0.18)x10(-5). We also set the limit -0. 04<F(V)-F(A)<0.24 at 90% C.L.

Further search for the decay K+-->pi(+)nunu;

A search for additional evidence for the rare kaon decay K+-->pi(+)nunu; has been made with a new data set comparable in sensitivity to the previous exposure that produced a single event. No new events were found in the pion momentum region examined, 211<P<229 MeV/c. Including a reanalysis of the original data set, the backgrounds were estimated to contribute 0.08+/-0.02 events. Based on one observed event, the new branching ratio is B(K+-->pi(+)nunu;) = 1.5(+3.4)(-1.2)x10(-10).

Tuberculous pleurisy with effusion

To assess the clinical features of Taiwanese patients with tuberculous pleurisy and their response to treatment, we analyzed the records of patients treated for this condition from December 1990 through November 1995, at a regional 100-bed referral center for tuberculosis care. Diagnosis of tuberculous pleurisy was based on histologic evidence of caseating granulomatous inflammation in the pleural biopsy specimen, or evidence of mycobacteria in pleural fluid. Patients were also stratified on the basis of parenchymal involvement. Ninety-seven patients (79 men, 18 women) with a mean age of 47.5 (range, 15-90) years were included in the analysis. The two major symptoms were cough (69%) and shortness of breath (57%). Chest roentgenographs showed that the pleural effusion was unilateral in 88 (91%) patients, and small to moderate in amount in 74 (76%). Laboratory analysis of the pleural fluid showed moderate levels of glucose (4.6 mmol/L), with no significant difference between patients with and without parenchymal involvement. The levels of lactate dehydrogenase and triglycerides were significantly higher in patients with parenchymal involvement (172 vs 240.5 IU and 0.36 vs 0.45 mmol/L, respectively). In 85 of 93 patients (91%) with available data, lymphocytes were predominant in the differential count. All patients had received short-course chemotherapy for at least 6 months. After excluding the defaulters and patients receiving subsequent management in other hospitals, the overall rate of successful treatment was 97% (72/74). There was no significant difference in the treatment outcome between patients with parenchymal involvement and those without. None of the successfully treated patients had a relapse within a mean follow-up period of 31.7 +/- 18.4 months. We conclude that current patients with tuberculous pleurisy in Taiwan are not young, and short-course chemotherapy with isoniazid, ethambutol, rifampicin, and pyrazinamide is an effective treatment. The presence of parenchymal tuberculous lesions does not appear to influence the treatment outcome.

Tuberculous empyema

The clinical courses of 35 tuberculous empyema patients were investigated retrospectively from November 1990 through November 1995. Most patients had nonspecific symptoms and signs but with far-advanced pulmonary parenchymal lesions in their chest roentgenographs. The effusions showed neutrophilic leukocytosis with a 60% positive culture rate for Mycobacterium tuberculosis. Multidrug resistant strains were found in 7 out of 18 cultures. All patients received chemotherapy and eight of them underwent additional surgical management. Twenty-two (62.9%) patients had been treated successfully and one patient is still under treatment. The remaining 12 patients either died during treatment or defaulted; and four (11.4%) of them had died of tuberculosis. We conclude that the treatment outcome of tuberculous empyema is less satisfactory than that of pulmonary tuberculosis, however, modern multidrug chemotherapy with repeated drainage and opportune surgical interventions could be in prospect of successful treatment of tuberculous empyema.

Drug resistance patterns of tuberculosis in Taiwan

To evaluate the patterns of drug resistance of Mycobacterium tuberculosis in Taiwan, a total of 1,091 isolates collected from patients from January 1996 through December 1996 were tested for drug susceptibility using the absolute concentration method at the Taiwan Provincial Chronic Disease Control Bureau. The overall drug rate of resistance to at least one drug was 35.5%. Among the 249 isolates from patients who had never been treated for tuberculosis, 16.1% were resistant to one or more drugs; 1.6% were resistant to at least isoniazid and rifampin. Of 200 patients with prior antituberculosis treatment, 67.0% had isolates resistant to one or more drugs and 46.0% had isolates resistant to at least isoniazid and rifampin. We conclude that drug-resistant M. tuberculosis is an important issue in tuberculosis treatment in Taiwan, especially when dealing with patients with a prior history of antituberculosis treatment. More aggressive interventions, such as directly observed therapy, short-course, are needed to improve the cure rate of pulmonary tuberculosis and to decrease resistance rates.

Short-course chemotherapy for isoniazid-resistant pulmonary tuberculosis

Standard short-course chemotherapy including isoniazid, rifampicin, pyrazinamide, and ethambutol has been the recommended treatment for tuberculosis in Taiwan since November 1990. The effectiveness of this treatment was evaluated retrospectively in 108 patients with isolates resistant to isoniazid alone and 115 patients with drug-susceptible pulmonary tuberculosis diagnosed and treated at the Taiwan Provincial Chronic Disease Control Bureau from November 1990 through December 1995. The success rate of treatment was 94.4% in patients with isoniazid-resistant Mycobacterium tuberculosis strains, which was not significantly different from the 97.4% rate in patients with susceptible strains. Of the patients treated successfully, no bacteriologic relapse was found in 97 patients with isoniazid-resistant strains or 103 patients with drug-susceptible strains 12 months after the end of chemotherapy. No significant advantage in treatment outcome was found in patients infected with isoniazid-resistant strains who received chemotherapy for more than 6 months (successful treatment rate, 95.0% vs 92.8%), but the failure rate was higher in patients with a previous history of antituberculosis therapy (17.6% vs 3.3%). We conclude that short-course chemotherapy is effective for isoniazid-resistant pulmonary tuberculosis and that there is no significant difference in treatment outcome between patients with or without isoniazid-resistant disease.

Serodiagnosis of tuberculosis. A study comparing three specific mycobacterial antigens

To compare the efficacy of different mycobacterial specific antigens and to assess the applicability of the combination of several different antigens in the diagnosis of tuberculosis, three ELISA tests derived by Antigen 60, 38kda, and Kp90 were evaluated in 594 Chinese patients (312 patients with active pulmonary tuberculosis and 282 control subjects). Quantified levels of sensitivity and specificity were compared with those in the nontuberculous control groups. Antigen 60 IgG (sensitivity and specificity, 80.77 and 88.4%) was more antigenic and more effective in its determination than was 38kda IgG (sensitivity and specificity, 64.21 and 80.74%) and Kp90 IgA (sensitivity and specificity, 62.58 and 66.3%). The clinical significance of the difference, however, was not striking: negative predictive value of Antigen 60, 38kda, and Kp90 was 93, 86 and 83%, respectively; positive predictive value of Antigen 60, 38kda, and Kp90 was 71, 54, and 39%, respectively. Combination of different antigens could improve the sensitivity and specificity by no more than 10%, with the sacrifice of the opposite parameter by no less than 20%. The same improvement in sensitivity could be easily achieved by adjusting the cutoff values in the ELISA test by a single antigen. We conclude that the sensitivity and specificity of presently available antigens for serodiagnosis of tuberculosis still remains limited at around 80%, which makes it a poor diagnostic tool for disease confirmation. In low incidence areas, its clinical value may be useful in disease exclusion. A combination of several different antigens provides no more improved diagnostic yield than what can be provided by cutoff value adjustment in a single antigen serologic test.