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Characterization Of Fluids And Gases
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
Tissue pH monitoring is a concept which is one outcome of the research. Tissue pH (tpH) is essentially the interstitial fluid pH. The extent to which tpH follows arterial and capillary blood pH has been a matter of extensive study. Tissue pH is not a direct indicator of metabolic status but rather reflects a combination of metabolic, respiratory and circulatory effects on the tissue. Deviations from arterial pH can therefore be expected. Some early investigators evaluating the electrode developed by Stamm et al.1 did not find a good correlation. Later on the improved electrode made by Roche Medical Electronics Inc. during experimental studies on the sheep gave variable correlations. Differences could not be explained by electrode drift and stabilization problems and possibly an important contributing factor was the nature of the microenvironment created by the electrode insertion process itself. Tissue pH values were seen to be within 0.08 units of arterial pH in 60% of the observations with differences ranging up to 0.17 units.2 In spite of this order of discrepancy the fact that the electrodes allowed continuous monitoring and eliminated the need of serial scalp blood sampling ensured a place for tissue pH measurement in fetal monitoring. Furthermore that tpH falls before arterial pH gives to tpH measurement a “margin of safety” and a somewhat early-warning potential.
Models of Experimental Hypertension
Published in John H. McNeill, Measurement of Cardiovascular Function, 2019
Salah D. Kivlighn, Gloria J. Zingaro, Robert A. Gabel, Theodore P. Broten, Peter K.S. Siegl
In a second surgery, under sterile operating conditions, a silver Goldblatt clamp (Figure 4; Propper Manufacturing Co., Inc., Long Island, NY) is placed on a renal artery (usually the left) through a retroperitoneal flank incision. During this procedure, renal blood flow must be monitored to titrate a consistent reduction in renal blood flow with the clamp. Noncanulating electromagnetic flow probes (Carolina Medical Electronics, King, NC and Zepeda Instruments, Seattle, WA) are excellent for this purpose.9 The flow probe is positioned on the renal artery, between the clamp and the aorta, to maintain good contact between the probe and the blood vessel. The manuals provided with the equipment are excellent resources for the calibration and operation of the flow probes and meters. The meters also interface easily with physiological recorders so that hard copies of the data can be obtained. The silver Goldblatt clip has an internal variable gap which is controlled by a small screw. The screw is progressively tightened until the renal blood flow is reduced and stabilized to 40 to 50% of the original flow.10 The probe is then removed and the incision closed with 2-0 chromic gut for the muscle and 2-0 silk sutures for the skin. The incision site should be cleaned again and bandaged. The animal should remain under observation until recovered from anesthesia. Postoperative care should be administered according to the advice of an attending veterinarian.
Radiation Therapy Politics
Published in Barbara Bridgman Perkins, Cancer, Radiation Therapy, and the Market, 2017
In turning to specialty and trade associations to formulate health-planning and Certificate of Need standards, the government assigned the foxes to guard the henhouse. The American College of Radiology and the National Electrical Manufacturers Association collaborated in developing guidelines for radiation therapy services.62 They chose the college’s 300-patient minimum-volume criterion, based on an estimated financial break-even point, to ensure that services could support themselves economically. The medical electronics industry also favored minimum volume standards, as larger institutions purchased more equipment.63 Health planning, as it was implemented under the 1974 law, was primarily a financial strategy.
Speech understanding and listening effort in cochlear implant users – microphone beamformers lead to significant improvements in noisy environments
Published in Cochlear Implants International, 2020
Andreas Büchner, Manfred Schwebs, Thomas Lenarz
At the beginning of the twenty-first century cochlear implantation was the treatment of choice only in cases of profound hearing loss or complete deafness. Since then, the indication criteria have continuously been relaxed as successive advances in cochlear implant (CI) technology have resulted in substantial hearing improvements over time. One cornerstone for improved hearing with a CI in challenging listening environments was the adoption of advanced signal enhancement algorithms and noise reduction methods from the hearing aid industry. While these algorithms have been refined in conventional hearing instruments since the introduction of digital signal processing in the late 1990s, they have only recently begun to be fully exploited in the world of cochlear implant signal processing. One significant contribution – particularly in adverse listening environments – is the development of microphone beamformers, which can significantly improve the signal to noise ratio in acoustic scenarios with spatially-separated sound sources. In 2014, MED-EL Medical Electronics GmbH (Innsbruck, Austria) introduced the SONNET audio processor. The SONNET has two spatially separated microphones which, like in hearing aids, can function as a beamformer by exploiting phase differences in the arriving sound signal. Beamformers can be used to produce a static pattern of directionality, where the point of maximum attenuation (i.e. null) is fixed, or an adaptive pattern, where the null dynamically follows the direction of a moving noise source.
Systemic immune-inflammation index is associated with increased carotid intima-media thickness in hypertensive patients
Published in Clinical and Experimental Hypertension, 2021
Ömer Faruk Çırakoğlu, Ahmet Seyda Yılmaz
Fasting blood samples were obtained from peripheral veins. Complete blood count parameters were measured by an auto hematology analyzer (Mindray Medical Electronics Co. Shenzhen, China). Serum albumin level was analyzed using automatic photometry commercial kits (OSR6202, Beckman Coulter, Inc., 250 S. Kraemer Blvd.Brea, USA). Serum CRP levels were measured with the nephelometric method (AU680 Clinical Chemistry Analyzer System; Beckman Coulter K.K., Tokyo, Japan). NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. The CAR was calculated as the ratio of serum CRP (mg/dl) to the albumin level (g/dl) and then multiplying the result by 100. SII was calculated according to the following formula: (platelet × neutrophil/lymphocyte counts).
Penetration of different molecule sizes upon ultrasound combined with microbubbles in a superficial tumour model
Published in Journal of Drug Targeting, 2019
Yingli Wei, Ning Shang, Hai Jin, Yan He, Yuwei Pan, Nina Xiao, Jinglu Wei, Shuyi Xiao, Liping Chen, Jianhua Liu
A pulsed therapeutic ultrasound device (DCT-700, Shenzhen Well.D Medical Electronics Co. Ltd. Shenzhen, China) was used with an ultrasound transducer (2 cm diameter) composed of an aluminium shell with the tip covered by a polyimide membrane. A needle hydrophone (TNU001A, NTR, Seattle, WA) was positioned to measure the acoustic output at a depth of 0.5 cm from the surface. Other acoustics parameters were as follows: frequency of transducer = 1 MHz; pulse repetition frequency = 100 Hz; acoustic pressure = 1 MPa; intermittent mode of transducer = 9 s (on) and 3 s (off); duty cycle = 1%; insonation time = 10 min. All insonation procedures were performed by the same experimenter.