Quantifying Step Count and Oxygen Consumption with Portable Technology during the 2-Min Walk Test in People with Lower Limb Amputation

Step counts and oxygen consumption have yet to be reported during the 2-min walk test (2MWT) test in persons with lower-limb amputations (LLA). The purpose of this study was to determine step counts and oxygen consumption during the 2MWT in LLA. Thirty-five men and women walked for two minutes as quickly as possible while wearing activity monitors (ActiGraph Link on the wrist (LW) and ankle (LA), Garmin vivofit®3 on the wrist (VW) and ankle (VA), and a modus StepWatch on the ankle (SA), and a portable oxygen analyzer. The StepWatch on the ankle (SA) and the vivofit3 on the wrist (VW) had the least error and best accuracy of the activity monitors studied. While there were no significant differences in distance walked, oxygen consumption (VO2) or heart rate (HR) between sexes or level of amputation (p > 0.05), females took significantly more steps than males (p = 0.034), and those with unilateral transfemoral amputations took significantly fewer steps than those with unilateral transtibial amputations (p = 0.023). The VW and SA provided the most accurate step counts among the activity monitors and were not significantly different than hand counts. Oxygen consumption for all participants during the 2MWT was 8.9 ± 2.9 mL/kg/min, which is lower than moderate-intensity activity. While some may argue that steady-state activity has not yet been reached in the 2MWT, it may also be possible participants are not walking as fast as they can, thereby misclassifying their performance to a lower standard.

RTA Mathematic Simulation Principles at the Autotechnical Expertise

The features of carrying out an autotechnical expertise (ATE) are considered in case the vehicles (V) participating in the road transport accident (RTA) don’t leave skid imprints. The examples of momentum and energy conservation law application are given at developing the road accident mathematical model. Special attention is paid to the determination methods of vehicle (V) velocity, travel directions in various RTA diagrams and archeology of deformation. For this purpose it is offered to draw a momentum vector diagram. It is reasonable that for the calculation of V deformation at RTA it is necessary to determine step by step the strain-stress state in a contact area on the basis of the theories of elasticity, plasticity, solid friction and finite-element methods. The technique of constructing an RTA mathematical model is developed. It is recommended to use at ATE of RTAs at the runs-over into the fixed obstacle (a stationary V) and collisions.

A Globally Convergent Line Search Filter SQP Method for Inequality Constrained Optimization

A line search filter SQP method for inequality constrained optimization is presented. This method makes use of a backtracking line search procedure to generate step size and the efficiency of the filter technique to determine step acceptance. At each iteration, the subproblem is always consistent, and it only needs to solve one QP subproblem. Under some mild conditions, the global convergence property can be guaranteed. In the end, numerical experiments show that the method in this paper is effective.

Walking disturbances at the Parkinsonism. New possibilities in the diagnosis, treatment and neyroprotection

The purpose of the study — to evaluate the effectiveness of the method tempo-rhythmic correction (TRC) distance in patients with Parkinson's disease (PD). We have used the device to determine step-speed performance rights, method TRC of walking, a questionnaire of quality of life of patients with PD (PDQ-39). Revealed that the method of TRC can improve walking in patients with Parkinson's disease, improve their life quality and reduce the pharmacoeconomic cost of treatment. Also, we have suggested a neuroprotective effect of the method of TRC.

Updated results of a phase I study of low dose decitabine and valproic acid (VA) in patients with acute myeloid leukemia (AML): Gene reexpression, demethylation, and clinical response

6515 Background: Decitabine, an inhibitor of DNA methyltransferase (DNMT) enzymes, has activity in myeloid malignancies at doses >1 log below the MTD of 2250mg/m2/course which may be optimal for DNA demethylation and minimize cytotoxicity. Methods: We designed a two step trial for AML patients (pts) to determine: Step 1, the lowest dose of decitabine to induce 100% increase in or re-expression of epigenetically silenced genes in 5/6 pts treated at a dose level; and Step 2, the MTD of the histone deacetylase (HDAC) inhibitor VA given with this dose of decitabine, and whether this MTD or a lower dose leads to 90% decrease in HDAC activity. Results: Decitabine was administered to 17 pts at two dose levels. Pts had relapsed/refractory AML (N=10) or age>60 and ineligible/refused standard therapy (N=7) and ranged in age from 36–83 years. Pts received decitabine at 15–20mg/m2/IV over 1 hr daily for 10 days (d) (3 pts also had VA 15mg/kg on days 5–21), every 28 d. Mean plasma decitabine Cmax (by a validated LC-MS/MS method) was 93 ng/ml (N=7). 10/13 pts had at least 100% increase in expression of p15 or estrogen receptor (ER, including 5/6 given 20mg/m2/d decitabine alone), and all 10 had clinical response. Of the 3 pts who did not have increased gene expression none responded. Western blotting showed depletion of DNMT protein in 4/6 pts. Bisulfite sequencing of the promoter region of ER confirmed that decitabine induced >50% decrease in methylation in the only pt yet examined (p<0.001). 9/14 pts had decrease in global DNA methylation as measured by LC-MS/MS. 10/15 pts had clinical benefit: 6 pts had clinical response, 2 with CR (1 with t-AML) and 4 with CRi (1 with a 20yr history of P. vera); 4 pts had clinical improvement-1 met all CR criteria except for BM disease by flow, 1 had platelet >100K, 2 had stabilization of disease for 4–6 months. Conclusions: We demonstrated clinical activity of low dose decitabine associated with decreased levels of the DNMT1 target and increased or re-expression of epigenetically silenced genes. Combination of decitabine at 20mg/m2/d with VA (Step 2) has begun; complete clinical results, gene re-expression/ demethylation, and histone deacetylation data will be presented. (NCI U01 CA 76576–05) [Table: see text]

The Optimum Design of Stepped Shafts: A Study in Computational Optimization

Optimum stepped shaft designs are obtained through an application of Pontryagin’s Minimum Principle. Optimum designs are obtained for a given critical speed of specified order. Indexes of Performance to be minimized include mass and rotating inertia. A general problem formulation illustrates how constraints on stress, deflections, and geometric design are taken in account. Numerical solutions are obtained to nonlinear multi-point-boundary-value-problems. A Newton-Raphson algorithm was developed to determine step locations precisely in order to facilitate the convergence of the shooting method used to solve the boundary value problem. Numerical solutions are determined with an assumed critical speed; a Rayleigh quotient calculation is used to verify that the optimum design possesses the assumed value.