31 research outputs found
Abnormal sperm morphology and the male fertility
If 60-70 years ago infertility was almost unknown or single families have had this problem, today it affects about 14% of couples of childbearing age, and this percentage tends to grow. A number of studies have shown that at about 40% of couples, infertility is due to changes in spermatogenesis. Infertility itself does not threaten the physical health of men, but creates a strong impact on mental and social well-being of married couples. Despite advances in modern urology, between 40% -50% of men, the diagnosis is `idiopathic infertility`. Thus, the term `unexplained infertility` is becoming one of the most established diagnoses.The present study was to determine the infertility distribution among a group of men with fertility problems, age range when it is observed, and the associated morphological defects in comparison to the WHO criteria. The study examines the extent of infertility, age groups and morphological characteristics of semen analysis in context to their possible role as factors for the infertility.The results obtained clearly reflect the global trend of harmful factors growth affecting spermatogenesis associated with lower sperm quantitative and qualitative indicators by the contemporary men
Influence of the tendon design on the behavior of an under-actuated finger
An investigation on the influence of the design parameters of the tendon system on the behavior of an under-actuated finger is presented. The study was carried on by simulations with Working Model 2Dâą and by an experimental apparatus.
The results showed a good agreement between simulation results and experiments. A correct choice of the design of the tendon system parameters permits a correct working of an under-actuated mechanical finger driven by un-extendable tendons; hence this study can help in correctly designing the finger of under-actuated grasping devices. This both for industrial and agricultural grasping devices and for human hand prosthesis
Concurrent lock-free unbounded priority queue with mutable priorities
The priority queue with DeleteMin and Insert operations is a classical interface for ordering items associated with priorities. Some important algorithms, such as Dijkstraâs single-source-shortest-path, Adaptive Huffman Trees, etc. also require changing the priorities of items in the runtime. Existing lock-free priority queues do not directly support the dynamic mutation of the priorities. This paper presents the first concurrent lock-free unbounded binary heap that implements a priority queue with mutable priorities. The operations are provably linearizable. We also designed an optimized version of the algorithm by combining the concurrent operations that substantially improves the performance. For experimental evaluation, we implemented the algorithm in both C/C++ and Java. A number of micro-benchmarks show that our algorithm performs well in comparison to existing implementations
Sliding Mode Impedance Controlled Smart Fingered Microgripper for Automated Grasp and Release Tasks at the Microscale
Part 5: Gripping and Handling Solutions in AssemblyInternational audienceThe grasp and release of objects have been widely studied in robotics. At the microscale, this problem becomes more difficult due to the microscale specificities which are notably manifested by the high dynamics of microsystems, their small inertia, their fragility, the predominance of surface forces and the high complexity of integrating adapted sensors.In this paper, the problem of the grasp/release task is considered at the microscale. A new nonlinear controller design based on Sliding Mode Impedance Control (SMIC) is proposed to automate the grasp/release of the micropart. The proposed controller controls dexterously the dynamic interaction between the microgripper and the micropart and forces the system to follow the desired dynamic relation (impedance). To perform the grasp/release task, a new smart-fingered-microgripper is designed. The microgripper is composed of an active finger with integrated force sensor and a passive finger.The grasp/release of a micropart of size 50 ”m 350 ”m 2 mm is tested in experiments using the control scheme and the developed microgripper. The microgripper design and the control scheme tested show their effectiveness for the grasp/release at the microscale