1,721,602 research outputs found

    Reducing the number of sequential diagnosis iterations in hypercubes

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    In this note, we use a vertex-isoperimetric inequality to show that the number of test and repair iterations needed to perform sequential diagnosis of d-dimensional hypercubes is upper bounded by d - r, where r is an element of theta(d). This result improves the best bound of d test and repair iterations previously known. Numerical evaluation has shown that the actual value of r ranges from 0.16d to 0.31d

    Pharmacological enhancement of cutaneous flap survival with topical dimethyl sulphoxide and hydrogen peroxide.

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    The present study was designed to investigate, in a rabbit model, the value of topical application of a solution of hydrogen peroxide (H2O2) 8% + dimethyl sulphoxide (DMSO) 50% in order to reduce ischaemic failure in random skin flaps. Two parallel, cephalad-based para-midline random cutaneous flap (10 cm x 2.5 cm) were elevated and resutured in place on the dorsum of 40 New Zealand rabbits. The 80 flaps thus obtained were then randomly divided into one control group and three experimental groups of 20 flaps each. Flaps from the control group (Group A) were topically treated with saline, while flaps from experimental Group B were treated with H2O2 8%, flaps from experimental Group C with DMSO 50%, and flaps from experimental Group D with a solution of 50% DMSO + 8% H2O2. Each solution was topically applied to the flaps, 20 ml three times a day for 7 days, starting in the immediate postoperative period. Transcutaneous oxygen tension (PtcO2) measurements were carried out in all flaps 72 h after flap evaluation. The percentage of surviving skin area of each flap was determined by planimetry 7 days after flap evaluation. The mean surviving area of Group A (control) flaps was 71%, the mean surviving area of the Group B (H2O2-treated) flaps was 72%, the mean surviving area of the Group C (DMSO-treated) flaps was 76%, and that of the Group D (DMSO + H2O2-treated) flaps was 92%. While no statistically significant differences were found between the survival rates of both the flaps treated with H2O2 or DMSO alone and that of the control group, the mean surviving rate of the DMSO + H2O2 treated flaps (+20%) was statistically higher than that of the control flaps. Similarly, a statistically significant difference has been found between the mean PtcO2 values of the DMSO + H2O2 flaps and those of the other three groups of flaps

    Crash faults identification in wireless sensor networks

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    In this paper we consider the problem of identifying faulty (crashed) nodes in a wireless sensor network. This problem is of fundamental importance in those applicative scenarios of wireless sensor networks in which battery replacement is feasible. The diagnostic information gathered by operational sensors can be used by an external operator for the sake of network reconfiguration and/or repair; thus extending network lifetime. A fault diagnosis protocol specifically designed for wireless sensor networks is introduced and analyzed. The protocol is proved to be optimal and energy efficient under certain assumptions. (C) 2002 Elsevier Science B.V. All rights reserved

    Topical application of DMSO as an adjunct to tissue expansion for breast reconstruction.

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    The aim of this study was to evaluate the effectiveness of topical 60% dimethyl sulphoxide (DMSO) prior to tissue expansion for breast reconstruction in reducing expander pressure and length of treatment. Forty patients undergoing immediate breast reconstruction with tissue expanders following modified radical mastectomy were consecutively divided into two groups of 20 subjects each: group A (control) and group B (experimental). Patients from group A underwent traditional tissue expansion, while, to patients of group B, before each filling session, topical 60% DMSO was applied to the skin overlying the expander by soaking-wet surgical sponges left in place for 30 min. The average inflated volume was 395 cc (range 250-580 cc) in group A, and 410 cc (range 240-620 cc) in group B; no statistically significant difference was found between these values. A statistically significant difference was found between the expansion time of group A (mean 6 sessions; range 4-10 sessions with one filling session per week) and group B (mean 4 sessions; range 2-6 sessions with one filling session per week). A statistically significant difference was also found between the average inflated volume per session of group A (90 cc; range 60-130 cc) and group B (120 cc; range 90-160 cc). According to the data obtained by tonometry, a statistically significant difference was found between the average pre-filling and post-filling pressures of group A (28.4 and 66.5 mmHg, respectively) and group B (22.1 and 64.3 mmHg, respectively). Clinical benefits of pre-filling topical applications of 60% DMSO observed in our trial were an enhancement of the total volume inflatable per session and a significant shortening of the total expansion period
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