Effects of different acceleration deceleration rates on isokinetic performance of the knee extensors.

The Kinetic Communicator provides three acceleration/deceleration rates (low, medium, and high) to control the limb and, thus, prevent impact forces and torque overshoot found with free acceleration. The purpose of this study was to examine the effect of three acceleration/deceleration rates on isokinetic performance of the knee extensors on the Kinetic Communicator. Thirty-one healthy females with no history of knee pathology performed three concentric/eccentric contractions of the knee extensors at each acceleration/deceleration rate at a velocity of 90 degrees /sec. A one-way repeated measures analysis of variance (ANOVA) and Scheffé post hoc tests were used to compare between each acceleration/deceleration rate: 1) the average velocity, peak torque, and average torque of the whole curve; and 2) the average velocity, average torque, and range of motion of the acceleration and deceleration phases. The acceleration/deceleration rate significantly affected the average velocity of the whole curve, acceleration phase, and deceleration phase. Although acceleration/deceleration rate had some effect on average torque in the acceleration and deceleration phases, peak torque and average torque of the whole curve were not significantly affected. Thus, in this study, the choice of acceleration/deceleration rate at 90 degrees /sec did not appear to have a clinically significant effect on average torque and peak torque for the whole curve. J Orthop Sports Phys Ther 1991;14(4):161-168.

The workshop on signatures of medical and industrial isotope production - WOSMIP; Strassoldo, Italy, 1-3 July 2009.

Radiopharmaceuticals make contributions of inestimable value to medical practice. With growing demand new technologies are being developed and applied worldwide. Most diagnostic procedures rely on (99m)Tc and the use of uranium targets in reactors is currently the favored method of production, with 95% of the necessary (99)Mo parent currently being produced by four major global suppliers. Coincidentally there are growing concerns for nuclear security and proliferation. New disarmament treaties such as the Comprehensive Nuclear-Test-Ban Treaty (CTBT) are coming into effect and treaty compliance-verification monitoring is gaining momentum. Radioxenon emissions (isotopes Xe-131, 133, 133m and 135) from radiopharmaceutical production facilities are of concern in this context because radioxenon is a highly sensitive tracer for detecting nuclear explosions. There exists, therefore, a potential for confusing source attribution, with emissions from radiopharmaceutical-production facilities regularly being detected in treaty compliance-verification networks. The CTBT radioxenon network currently under installation is highly sensitive with detection limits approaching 0.1 mBq/m³ and, depending on transport conditions and background, able to detect industrial release signatures from sites thousands of kilometers away. The method currently employed to distinguish between industrial and military radioxenon sources involves plots of isotope ratios (133m)Xe/(131m)Xe versus (135)Xe/(133)Xe, but source attribution can be ambiguous. Through the WOSMIP Workshop the environmental monitoring community is gaining a better understanding of the complexities of the processes at production facilities, and the production community is recognizing the impact their operations have on monitoring systems and their goal of nuclear non-proliferation. Further collaboration and discussion are needed, together with advances in Xe trapping technology and monitoring systems. Such initiatives will help in addressing the dichotomy which exists between expanding production and improving monitoring sensitivity, with the ultimate aim of enabling unambiguous distinction between different nuclide signatures.

Mre11 nuclease and C-terminal tail-mediated DDR functions are required for initiating yeast telomere healing.

Mre11 is a central factor in creating an optimal substrate for telomerase loading and elongation. We have used a G2/M synchronized telomere-healing assay as a tool to separate different functions of Mre11 that are not apparent in null alleles. An analysis of healing efficiencies of several mre11 alleles revealed that both nuclease and C-terminal mutations led to a loss of healing. Interestingly, trans-complementation of the 49 amino acid C-terminal deletion (DeltaC49) and the D16A mutant, deficient in nuclease activity and partially defective in MRX complex formation, restores healing. DeltaC49 provokes Rad53 phosphorylation after treatment with the radiomimetic agent MMS exclusively through the Tel1 pathway, suggesting that a Tel1-mediated function is initiated through the C-terminal tail.