In vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are the most commonly used assisted reproductive technologies to overcome male infertility problems. One of the obstacles of IVF and ICSI procedures is separating motile sperm from non-motile sperm to select the most competent sperm population from any given sperm sample. In addition, orientation and separation of the head from the tail is another obstacle for ICSI. Using the self-movement of sperm against flow direction, motile and non-motile sperm can be separated with an inexpensive polymeric microfluidic system. In this paper, we describe the development of a microfluidic system obtained through low-cost fabrication processes. We report experimental results of sperm sorting using hydrostatic pressure of three different species: bull, mouse, and human. The movement of cells in these channels was observed under a microscope and recorded with a digital camera. It is shown that the hydrostatic pressure and self-movement of motile sperm can be used to solve separating, aligning and orienting sperm in the microchannel.

We present a nano‐W dispersed polymer composite whose gamma attenuation is greatly enhanced. In situ pulverization and simultaneous encapsulation of polyethylene (PE) onto the nano‐W particles was successfully performed by ball milling. Adhesive encapsulation of PE was observed by means of interstitial diffusion of atomic W at the boundary using transmission electron microscope. Prepared nano‐W/PE particles were dispersed into ethylene‐propylene‐based polymer mixture using melt mixing. Attenuation of gammas for the nano‐W composites was enhanced up to ∼75% for Ba‐133 (∼0.3 MeV) compared to the micro‐W composites, while it decreases as the photon energy increases. MCNP simulation also shows similar gamma attenuation behaviors.

No abstract

No abstract

No abstract