Quantitative assessment of aortic sclerosis using ultrasonic backscatter

Background. The development of therapeutic interventions to prevent progressive valve damage is more likely to limit the progression of structural damage to the aortic valve with normal function (aortic sclerosis [ASC]) than clinically apparent aortic stenosis. Currently, the ability to appreciate the progression of ASC is compromised by the subjective and qualitative evaluation of sclerosis severity. Methods: We sought to reveal whether the intensity of ultrasonic backscatter could be used to quantify sclerosis severity in 26 patients with ASC and 23 healthy young adults. images of the aortic valve were obtained in the parasternal long-axis view and saved in raw data format. Six square-shaped 11 X 11 pixel regions of interest were placed on the anterior and posterior leaflets, and calibrated backscatter values were obtained by subtracting the regions of interest in the blood pool from the averaged backscatter values obtained from the leaflets. Results. Mean ultrasonic backscatter values for sclerotic valves exceeded the results in normal valve tissue (16.3 +/- 4.4 dB vs 9.8 +/- 3.3 dB, P < .0001). Backscatter values were greater (22.0 +/- 3.5 dB) in a group of 6 patients with aortic stenosis. Within the sclerosis group, the magnitude of backscatter was directly correlated (P < .05) with a subjective sclerosis score, and with transvalvular pressure gradient. mean reproducibility was 2.4 +/- 1.8 dB (SD) between observers, and 2.3 +/- 1.7 dB (SD) between examinations. Conclusion: Measurement of backscatter from the valve leaflets of patients with ASC may be a feasible means of following the progression and treatment response of aortic sclerosis.

Testing the reliability of a new ultrasonic cardiac output monitor, the USCOM, by using aortic flowprobes in anesthetized dogs

We have used an animal model to test the reliability of a new portable continuous-wave Doppler ultrasonic cardiac output monitor, the USCOM. In six anesthetized dogs, cardiac output was measured with a high-precision transit time ultrasonic flowprobe placed on the ascending aorta. The dogs' cardiac output was increased with a dopamine infusion (0-15 mug (.) kg(-1) (.) min(-1)). Simultaneous flowprobe and USCOM cardiac output measurements were made. Up to 64 pairs of readings were collected from each dog. Data were compared by using the Bland and Altman plot method and Lin's concordance correlation coefficient. A total of 319 sets of paired readings were collected. The mean (+/-SD) cardiac output was 2.62 +/- 1.04 L/min, and readings ranged from 0.79 to 5.73 L/min. The mean bias between the 2 sets of readings was -0.01 L/min, with limits of agreement (95% confidence intervals) of -0.34 to 0.31 L/min. This represents a 13% error. In five of six dogs, there was a high degree of concordance, or agreement, between the 2 methods, with coefficients >0.9. The USCOM provided reliable measurements of cardiac output over a wide range of values. Clinical trials are needed to validate the device in humans.

Comparison of gelation profile of yoghurts during fermentation measured by RVA and ultrasonic spectroscopy

The gelation profile of yoghurts from conventionally treated (85 degrees C/30 min) and UHT treated (143 degrees C/6s) milks at 16, 18, and 20% total solids was analyzed during fermentation for 4 hrs using the invasive Rapid Visco Analyzer (RVA) and the non-invasive ultrasonic spectroscope. The viscosity measured by the RVA and the ultrasonic velocity measured by the ultrasonic spectroscope exhibited similar sigmoid trends with respect to fermentation time. The ultrasonic spectroscope detected the onset of gelation of yoghurt milk earlier (by an average of 52 min) than did the RVA, indicating a higher sensitivity of ultrasonic spectroscopy. The delay of gelation time of UHT-treated yoghurt milk as compared to conventionally treated yoghurt milk was detected by both techniques. A non-significant ( P > 0.05) effect of solids content in the yoghurt milks on their gelation time was also observed by both instruments.

Improving the economic decision making capability and viability of Chinese wool textile mills

The successful restructuring of Chinese industries is of immense importance not only for the continued development of China but also to the stability of the world economy. The transformation of the Chinese wool textile industry illustrates well the many problems and pressures currently facing most Chinese industries. The Chinese wool textile industry has undergone major upheaval and restructuring in its drive to modernize and take advantage of developments in world textile markets. Macro level ownership and administrative reforms are well advanced as is the uptake of new technology and equipment. However, the changing market and institutional environment also demands an increasing level of sophistication in mill management decisions including product selection, input procurement, product pricing, investment appraisal, cost analysis and proactive identification of new market and growth opportunities. This paper outlines a series of analyses that have been integrated into a decision-making model designed to assist mill managers with these decisions. Features of the model include a whole-of-mill approach, a design based on existing mill structures and information systems, and the capacity for the model to be tailored to individual mills. All of these features facilitate the adoption of the model by time and resource constrained managers seeking to maintain the viability of their enterprises in the face of extremely dynamic market conditions.

Ultrasonic measurement technique of burning metals in normal and reduced gravity

The in situ real time measurement of the regression rate of a melting interface (RRMI) is performed by the ultrasonic measurement system reported here. The RRMI is the rate at which a solid/liquid interface (SLI) moves along a metallic rod while burning in an oxygen-enriched atmosphere and is an important flatnmability indicator. The ultrasonic transducer and associated equipment used to drive the transducer and record the echo signal is described, along with the process that transforms the acquired signals into a RRMI value. Test rods of various metals and geometric shapes were burned at several test conditions in different test facilities. The RRMI results with quantified errors are presented and reviewed. The effect of reduced gravity on burning metals is important to space-applications and RRMI results obtained in a reduced gravity environment are also presented.