A Newly Developed mm-Wave Sensor for Detecting Plaques of Arterial Vessels

2017 ◽  
Vol 66 (01) ◽  
pp. 091-098
Author(s):  
Markus Detert ◽  
David Wagner ◽  
Jan Wessel ◽  
Rabia Ramzan ◽  
Wilhelm Nimphius ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Plaque Formation ◽  
Fatty Tissue ◽  
Clinical Use ◽  
Tissue Water Content ◽  
Microwave Technology ◽  
Tissue Water ◽  
New Techniques ◽  
Fibrous Cap ◽  
Plaque Detection

Background Microcalcifications within the fibrous cap of the arteriosclerotic plaques lead to the accrual of plaque-destabilizing mechanical stress. New techniques for plaque screening with small detectors and the ability to differentiate between the smooth and hard elements of plaque formation are necessary. Method Vascular plaque formations are characterized as calcium phosphate containing structures organized as hydroxylapatite resembling the mineral whitlockite. In transmission and reflexion studies with a simple millimeter wave (mm-wave)–demonstrator, we found that there is a narrow window for plaque detection in arterial vessels because of the tissue water content, the differentiation to fatty tissue, and the dielectric property of air or water, respectively. Result The new sensor is based on a sensing oscillator working around 27 GHz. The open-stub capacitance determines the operating frequency of the sensor oscillator. The capacitance depends on the dielectric properties of the surrounding material. The sensor components were completely built up in surface mount technique. Conclusion Completed with a catheter, the sensor based on microwave technology appears as a robust tool ready for further clinical use.

scholarly journals Isoflurane in Contrast to Propofol Promotes Fluid Extravasation during Cardiopulmonary Bypass in Pigs

2013 ◽  
Vol 119 (4) ◽  
pp. 861-870 ◽  
Author(s):  
Hege Kristin Brekke ◽  
Stig Morten Hammersborg ◽  
Steinar Lundemoen ◽  
Arve Mongstad ◽  
Venny Lise Kvalheim ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Water Content ◽  
Interstitial Fluid ◽  
Outcome Analysis ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Edema Formation ◽  
Fluid Extravasation ◽  
Isoflurane Anesthesia ◽  
Total Tissue

Abstract Background: A highly positive intraoperative fluid balance should be prevented as it negatively impacts patient outcome. Analysis of volume-kinetics has identified an increase in interstitial fluid volume after crystalloid fluid loading during isoflurane anesthesia. Isoflurane has also been associated with postoperative hypoxemia and may be associated with an increase in alveolar epithelial permeability, edema formation, and hindered oxygen exchange. In this article, the authors compare fluid extravasation rates before and during cardiopulmonary bypass (CPB) with isoflurane- versus propofol-based anesthesia. Methods: Fourteen pigs underwent 2 h of tepid CPB with propofol (P-group; n = 7) or isoflurane anesthesia (I-group; n = 7). Fluid requirements, plasma volume, colloid osmotic pressures in plasma and interstitial fluid, hematocrit levels, and total tissue water content were recorded, and fluid extravasation rates calculated. Results: Fluid extravasation rates increased in the I-group from the pre-CPB level of 0.27 (0.13) to 0.92 (0.36) ml·kg−1·min−1, but remained essentially unchanged in the P-group with significant between-group differences during CPB (pb = 0.002). The results are supported by corresponding changes in interstitial colloid osmotic pressure and total tissue water content. Conclusions: During CPB, isoflurane, in contrast to propofol, significantly contributes to a general increase in fluid shifts from the intravascular to the interstitial space with edema formation and a possible negative impact on postoperative organ function.

Bénéfices à court terme des mouvements anadromes saisonniers pour une population d'omble de fontaine (Salvelinus fontinalis) du Nouveau Québec

1991 ◽  
Vol 48 (11) ◽  
pp. 2212-2222 ◽  
Author(s):  
Jean-François Doyon ◽  
Christiane Hudon ◽  
Roderick Morin ◽  
F. G. Whoriskey Jr.
Keyword(s):  
Water Level ◽  
Egg Size ◽  
Salvelinus Fontinalis ◽  
Condition Factor ◽  
Size At Maturity ◽  
Brook Charr ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Single Population ◽  
Energetic Reserves

This study characterizes the seasonal anadromous movements of a brook charr population and compares its biological and energetic characteristics with charr spending summer in freshwaters. Downstream movements monitored at a counting fence over 3 yr were most intense in spring but occurred until fall and were positively correlated with rapid increases of water level. The timing of movements varied from year to year. Smaller charr were most subject to being swept downstream compared with freshwater residents, and most trout were concentrated near the mouth of the river. These patterns suggest that the downstream movements of charr in this system are passive. Upstream migrants had a higher condition factor and a lower tissue water content than freshwater residents, indicating that downstream movements result in a faster accumulation of energetic reserves during summer. However, the fortuitous character of anadromous migrations as well as the absence of differences in the biological characteristics (growth, size at maturity, fecundity, egg size) suggests that anadromous and resident fish belong to a single population whose yearly migrant component could be randomly determined.

Detection of bark lesions caused by Phytophthoracinnamomi in Eucalyptusmarginata with the plant impedance ratio meter and the Shigometer

1987 ◽  
Vol 17 (10) ◽  
pp. 1228-1233 ◽  
Author(s):  
Joanna T. Tippett ◽  
Joanne L. Barclay
Keyword(s):  
Water Content ◽  
Electrical Resistance ◽  
Water Status ◽  
Healthy Tissue ◽  
Plant Tissues ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Impedance Ratio ◽  
New Instrument ◽  
Electrical Admittance

A new instrument, the plant impedance ratio meter (PIRM), has been used to determine the extent of lesions caused by Phytophthoracinnamomi Rands in Eucalyptusmarginata Sm. The performance of the PIRM, which measures electrical admittance (the inverse of impedance) of plant tissues at two frequencies (from which an impedance ratio is calculated), was evaluated and compared with that of the Shigometer. The electrical admittance measured at 1 and 10 kHz (PIRM) and the electrical resistance (Shigometer) of healthy tissue varied with both the depth of tissue probed and the water status of stems. However, the impedance ratios (calculated from the admittance values) remained relatively constant for healthy tissue and changes were independent of depth of probing. Hence, changes in ratios indicated a change in tissue condition or necrosis rather than changes in either tissue water content or depth of probing. The impedance ratios recorded for healthy bark tissues were consistently higher than those for the P. cinnamomi lesions in E. marginata. Trends in electrical resistance measured across the boundaries of the lesions with the Shigometer were variable depending on lesion age. The PIRM was used successfully to detect P. cinnamomi lesions in E. marinate and lesion fronts were predicted to an accuracy of ± 7.2 mm (n = 150), lesions being up to 1.0 m long at the time stems were harvested.

scholarly journals Algorithm for Mapping Kidney Tissue Water Content during Normothermic Machine Perfusion Using Hyperspectral Imaging

Algorithms ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 289
Author(s):  
Wenke Markgraf ◽  
Jannis Lilienthal ◽  
Philipp Feistel ◽  
Christine Thiele ◽  
Hagen Malberg
Keyword(s):  
Water Content ◽  
Hyperspectral Imaging ◽  
Wavelength Range ◽  
Kidney Tissue ◽  
Reflectance Spectra ◽  
Machine Perfusion ◽  
Least Squares Regression ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Normothermic Machine Perfusion

The preservation of kidneys using normothermic machine perfusion (NMP) prior to transplantation has the potential for predictive evaluation of organ quality. Investigations concerning the quantitative assessment of physiological tissue parameters and their dependence on organ function lack in this context. In this study, hyperspectral imaging (HSI) in the wavelength range of 500–995 nm was conducted for the determination of tissue water content (TWC) in kidneys. The quantitative relationship between spectral data and the reference TWC values was established by partial least squares regression (PLSR). Different preprocessing methods were applied to investigate their influence on predicting the TWC of kidneys. In the full wavelength range, the best models for absorbance and reflectance spectra provided Rp2 values of 0.968 and 0.963, as well as root-mean-square error of prediction (RMSEP) values of 2.016 and 2.155, respectively. Considering an optimal wavelength range (800–980 nm), the best model based on reflectance spectra (Rp2 value of 0.941, RMSEP value of 3.202). Finally, the visualization of TWC distribution in all pixels of kidneys’ HSI image was implemented. The results show the feasibility of HSI for a non-invasively and accurate TWC prediction in kidneys, which could be used in the future to assess the quality of kidneys during the preservation period.

Fluid and electrolyte changes of thyroidectomized rats in a cold environment

1959 ◽  
Vol 196 (6) ◽  
pp. 1214-1217 ◽  
Author(s):  
Joseph B. Boatman ◽  
John M. Walsh ◽  
Leonard I. Epstein ◽  
Marvin J. Rabinovitz
Keyword(s):  
Cold Exposure ◽  
Room Temperature ◽  
Specific Activity ◽  
Albino Rats ◽  
Cold Environment ◽  
Total Water ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Sodium Potassium ◽  
Sodium Flux

Groups of adult male albino rats were thyroidectomized or sham-operated, and later subjected to 10 day, 5°C cold exposure or else maintained at 22°C room temperatures. Tissues were examined for total water, sodium, potassium, Na24 and I131-thyroxine distribution. Thyroidectomized animals in the cold showed significantly greater amounts of water and Na24 specific activity in muscle and brain. Sham-operated animals in the cold showed significantly reduced brain Na24 specific activity. Thyroxine I131/Na24 ratios in tissue were greater at room temperature in thyroidectomized animals and were decreased with cold. Sham-operated animals showed no differences in brain thyroxine I131/Na24 ratios after equilibration and small differences in muscle ratios, with cold. It was concluded that a cold environment imposed on thyroidectomized animals resulted in changes in the animal's capacity to readjust body fluids and electrolytes when compared with intact animals exposed to cold. These differences were attributable to greater tissue water content and increased sodium flux into the tissues.

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