ABSTRACT
Tape stripping is a standard measuring method for the investigation of the dermatopharmacokinetics of topically applied substances using adhesive films. These tape strips are successively applied and removed from the skin after application and penetration of topically applied substances. Thus, layers of corneocytes and some amount of topical applied substances are removed. The amount of substances and the amount of stratum corneum removed with a single tape strip has to be determined for the calculation of the penetration profile. The topically applied substances removed from the skin can be determined by classical analytical methods like high-pressure liquid chromatography, mass spectroscopy, and spectroscopic measurements. The amount of corneocytes on the tape strips can be easily detected by their pseudoabsorption. In the present paper, an easy and cheap corneocyte density analyzer is presented that is based on a slide projector. Comparing the results of the measurements obtained by the corneocyte density analyzer and by uv-visible spectrometry, identical results were obtained.
Subject(s)
Cell Count/instrumentation , Clobetasol/administration & dosage , Clobetasol/pharmacokinetics , Keratinocytes/cytology , Keratinocytes/metabolism , Skin Absorption/physiology , Surgical Tape , Administration, Topical , Adult , Cell Count/methods , Equipment Design , Equipment Failure Analysis , Humans , Optics and Photonics/instrumentation , Photometry/instrumentation , Photometry/methodsABSTRACT
A new approach in radio frequency (rf) electrosurgery, used for tissue treatment, is achieved by using a new process control method. An external control unit allows a commonly available rf-generator to automatically supply the appropriate power for differing tissue types, thus ensuring best cutting quality. The sparks, generated during the scalpel electrode interaction with the tissue, appear statistically distributed. The spark rate depends on various factors and is monotonic with the supplied electrical power. This allows it to be used as the controlled variable in the cutting process. The ac current passing through the tissue is evaluated by an external control unit using an analyzation algorithm to determine the number of sparks. The external unit is comprised of a system, which measures the spark rate, and a subsequent proportional integral (P.I.) controller. The functionality of the control method as well as the electrical circuitry is verified through cuts with different degrees of carbonization and cuts through tissue heterojunctions.
Subject(s)
Electrosurgery/instrumentation , Adipose Tissue/surgery , Animals , Electric Conductivity , Electrodes , Equipment Design , In Vitro Techniques , Muscle, Skeletal/surgery , SwineSubject(s)
Electrocoagulation/instrumentation , Neoplasms/surgery , Aerosols , Equipment Design , Humans , Neoplasm Seeding , Treatment OutcomeABSTRACT
Based on the well known Kelvin probe for work function measurements a new microstructure analysis system - the Scanning Kelvin Microscope - has been developed. It allows to measure simultaneously with high lateral resolution the distribution of the contact potential difference (CPD) between a conductive sample and a reference probe together with the topographical structure of the sample surface. The measurement is contact free and non-destructive and can be carried out in natural environments. At present the lateral resolution of the measurement approaches 5 microm. The results can be displayed on a computer in three dimensional colour pictures.
Subject(s)
Oxygen/blood , Pacemaker, Artificial , Aged , Cardiac Output , Computer Simulation , Equipment Design , Heart Block/physiopathology , Heart Block/therapy , Heart Rate , Humans , Middle Aged , Models, Cardiovascular , VeinsABSTRACT
Right ventricular oxygen saturation (SO2) may be an ideal sensor for determining the rate of an implanted pacemaker. In order to prove this hypothesis, the obtained signals were optimally analyzed; determinations of SO2 at rest and during exercise were made in healthy volunteers and in patients with pacemakers; and an algorithm was developed for varying pacing rate as a function of measured SO2. The results suggest that this method may be applicable to the long-term implantee.
Subject(s)
Arrhythmias, Cardiac/physiopathology , Cardiac Pacing, Artificial/methods , Heart/physiology , Oxygen/blood , Pacemaker, Artificial , Body Temperature , Electrodes, Implanted , Heart Block/physiopathology , Heart Rate , Heart Ventricles/physiopathology , Humans , Sick Sinus Syndrome/physiopathology , Ventricular FunctionABSTRACT
Presently available physiologic pacing systems do not fully restore rate regulation, especially in respect to little or no atrial response to activity. Other biologic parameters, detected by sensors, may provide the physiologic responsiveness necessary to rate-regulating pacemakers. An optical sensor using mixed venous oxygen saturation may be the ideal parameter for such a pacing system. At present, further research is necessary to elaborate a suitable algorithm for optimal rate control.
