Microfabrication of Individual 200μm Diameter Transdermal Microconduits Using High Voltage Pulsing in Salicylic Acid and Benzoic Acid

We describe an extension of semiconductor fabrication methods that creates individual ≈ 200;μm diameter aqueous pathways through human stratum corneum at predetermined sites. Our hypothesis is that spatially localized electroporation of the multilamellar lipid bilayer membranes provides rapid delivery of salicylic acid to the keratin within corneocytes, leading to localized keratin disruption and then to a microconduit. A microconduit penetrating the isolated stratum corneum supports a volumetric flow of order 0.01;ml per s with a pressure difference of only 0.01;atm (about 102;Pa). This study provides a method for rapidly microengineering a pathway in the skin to interface future devices for transdermal drug delivery and sampling of biologically relevant fluids

Multithreaded Aapplication for Real-Time Visualization of ECG Signal Waveforms and Their Spectrums

By using concept of virtual instrumentation, signals from human body can be digitized and transferred to computer for further processing. Software in a computer enables use of modern tools for digital signal processing that can be improved easily with emergence of new knowledge and with increasing of computer performances. Presenting the ECG signal in both: Time and Time-Frequency domains enables to cardiologist to obtain more reliable diagnosis. In order to present simultaneously the waveform and spectrogram of ECG signal in the real time we use Fast Fourier and Discrete Wavelet transform in the multithreading environment of a standard personal computer. The synchronization of accessing the signal data by threads according to the principle one thread a time is performed by controlling the state of event type variables

Autonomic Effects of Controlled Fine Particulate Exposure in Young Healthy Adults: Effect Modification by Ozone

Background: Human controlled-exposure studies have assessed the impact of ambient fine particulate matter on cardiac autonomic function measured by heart rate variability (HRV), but whether these effects are modified by concomitant ozone exposure remains unknown. Objective: In this study we assessed the impact of O$_3$ and particulate matter exposure on HRV in humans. Methods: In a crossover design, 50 subjects (19–48 years of age) were randomized to 2-hr controlled exposures to filtered air (FA), concentrated ambient particles (CAPs), O$_3$, or combined CAPs and ozone (CAPs + O$_3$). The primary end point was change in HRV between the start and end of exposure. Secondary analyses included blood pressure (BP) responses, and effect modification by asthmatic status. Results: Achieved mean CAPs and O$_3$ exposure concentrations were 121.6 ± 48.0 μg/m$^3$ and 113.9 ± 6.6 ppb, respectively. In a categorical analysis, exposure had no consistent effect on HRV indices. However, the dose–response relationship between CAPs mass concentration and HRV indices seemed to vary depending on the presence of O$_3$. This heterogeneity was statistically significant for the low-frequency component of HRV (p = 0.02) and approached significance for the high-frequency component and time-domain measures of HRV. Exposure to CAPs + O$_3$ increased diastolic BP by 2.0 mmHg (SE, 1.2; p = 0.02). No other statistically significant changes in BP were observed. Asthmatic status did not modify these effects. Conclusion: The potentiation by O$_3$ of CAPs effects on diastolic BP and possibly HRV is of small magnitude in young adults. Further studies are needed to assess potential effects in more vulnerable populations

Basic Atomic Physics

Contains reports on five research projects.Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322National Science Foundation Grant PHY 92-22768Charles S. Draper Laboratory Contract DL-H-4847759U.S. Army - Office of Scientific Research Grant DAAL03-92-G-0229U.S. Army - Office of Scientific Research Grant DAAL01-92-6-0197U.S. Navy - Office of Naval Research Grant N00014-89-J-1207Alfred P. Sloan FoundationNational Science Foundation Grant PHY 95-01984U.S. Army Research Office Contract DAAL01-92-C-0001U.S. Navy - Office of Naval Research Grant N00014-90-J-1642U.S. Navy - Office of Naval Research Grant N00014-94-1-080

The Interdialytic Creatinine Rise is a novel marker of volume overload and mortality risk in hemodialysis patients

Abstract Background Volume overload poses a major risk in hemodialysis patients but simple detection methods are lacking. We propose a novel marker, the Interdialytic Creatinine Rise (IDCR), readily calculated as the change in serum creatinine over time (in mg/dL/h), to assess volume overload and predict mortality risk in hemodialysis patients. Methods First, we calculated IDCR changes with volume in a prospective cohort of 35 hospitalized hemodialysis patients awaiting hemodialysis and 33 hospitalized patients undergoing hemodialysis every other day. Second, in a prospective cohort of 25 outpatients, IDCR cutoff values associated with hypervolemia were determined between two treatments and compared with simultaneous volume assessments by their nephrologist. Third, IDCR as a mortality predictor was studied using survival analysis in a longitudinal retrospective cohort study of 39 maintenance hemodialysis patients followed from 2012 until death or 2017. Results IDCR decreased by − 0.014 mg/dL/h each day (95%CI − 0.017,− 0.010; p < 0.001) without dialysis due to fluid volume gain and increased by 0.013 mg/dL/h (95%CI 0.008,0.017; p < 0.001) from before to after each successive hemodialysis due to fluid removal. Choosing an IDCR cutoff value of ≤0.1 had sensitivity of 82% and specificity of 79% in diagnosing volume overload with the area under the ROC curve of 0.78 (95%CI 0.59,0.97). The hazard ratio of death for each 0.01 decrease in IDCR was 1.64 (95%CI 1.31,2.07; p < 0.001). If IDCR decreased to less than 0.05 mg/dL/h, the median survival was 32 days and the odds ratio of death within 2 months was 38 (95%CI 8, 131; p < 0.001). Conclusions In this pilot study, IDCR is shown to be a novel metric that decreases with fluid retention and increases after fluid removal. IDCR can assist clinicians in detection or exclusion of volume overload in hemodialysis patients and provide prognostic value in identifying those at high risk for death