PubMed Health⌕ Search

PubMed · 6415243

Microprocessor-controlled scanning micromanipulator for carbon dioxide laser surgery. Technical note.

Abstract

A microprocessor-controlled scanning device for use in carbon dioxide laser surgery is described. This device increases the speed of dissection, allows the surgeon to keep both hands in the operative field, and thereby decreases the fatigue associated with manual control of the micromanipulator used in a surgical laser system.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Dagan, J H Robertson, W C Clark. 1983. Microprocessor-controlled scanning micromanipulator for carbon dioxide laser surgery. Technical note.. https://doi.org/10.3171/jns.1983.59.6.1098

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Microparticles of soy lecithin formed by supercritical processes.

Finely divided particles of phospholipids are used to form controlled drug delivery systems called liposomes. Conventional physicochemical methods for preparing these microparticles are hampered by a major drawback-the use of organic solvents that remain at few but inhibitory concentration in the final product. This study aimed to propose an alternative method for preparing microparticles of phospholipids starting from soy lecithin-the process had to be free of solvent or at least, the solvent had to be nontoxic. Two micronization techniques based on the use of supercritical carbon dioxide were investigated: the RESS and the SAS processes. The RESS process failed to separate the particles formed from the cosolvent. Performing the SAS process with ethanol as auxiliary solvent, enabled fine particles to form with size ranging from 1 to 40 microm. Particles were spherical and partly agglomerated and seemed to be free of solvent as shown by preliminary infrared analysis.

Carbon Dioxide↗

Multiple modeling in the study of interaction of hemodynamics and gas exchange.

Circulation plays an important rule in gas exchange. Therefore, there is an interaction between circulation and gas exchange. To understand the dynamic effect of these two physiological systems, a computer simulation model of hemodynamics and gas exchange is established in this work. This model includes two physiological systems, namely the respiratory and circulatory systems. It consists of five parts: the model of gas transport, exchange and storage within the body, the multi-element nonlinear mathematical model of human circulatory system, an alveolar ventilation controller, a cardiac output controller, and a controller of breathing frequency. Model simulations provide results consistent with both dynamic and steady-state responses under hypoxia. Simulation results can reflect the interaction of hemodynamics and gas exchange. Using this model, the changes of pulmonary arterial pressure and right ventricular pressure in high altitude are studied. The optimal mode of breathing extra oxygen using nasal prongs or a facial mask is studied. This model may provide a useful tool to study reaction of hypoxia and the oxygen inhalation mode under hypoxia environments.

Carbon Dioxide↗

Periodic spectral components of fetal heart rate variability reflect the changes in cord arterial base deficit values: a preliminary report.

Fetal distress changes the function of the autonomic nervous system. These changes are reflected in the fetal heart rate and can be quantified with power spectrum analysis of heart rate variability. The purpose of this study was to find out whether spectral components of fetal heart rate variability (FHRV) during labor are associated with fetal cord arterial base deficit values at birth. The association between FHRV and umbilical cord arterial base deficit was studied in 14 singleton fetuses with normal pregnancy at 35-40 weeks of gestation. Fetal ECG was recorded by scalp-electrode using a STAN Fetal ECG monitor (Cinventa Ab, Mölndal, Sweden). FHRV was quantified by computing Fast-Fourier-transformed heart rate (HR) spectra at three frequency bands: low-frequency (LF) 0.03-0.07 Hz, mid-frequency (MF) 0.07-0.13 Hz and high-frequency (HF) 0.13-1.0 Hz. We found that total FHRV and MF FHRV were lower in fetuses with cord arterial base deficit 8 to 12 mmol/L in comparison to the fetuses with normal cord arterial base deficit value (P=0.02 and P=0.01, respectively). A linear correlation was found between the spectral densities and the cord arterial base deficit values (r=0.4 and r=0.6, respectively). We conclude that the results suggest changes in the autonomic nervous cardiac control in fetuses with cord arterial base deficit between 8 to 12 mmol/L. The clinical applicability of our observations on FHRV in predicting fetal distress remains to be further studied.

Carbon Dioxide↗