Smooth parametric surfaces and n-sided patches

The theory of 'geometric continuity' within the subject of CAGD is reviewed. In particular, we are concerned with how parametric surface patches for CAGD can be pieced together to form a smooth Ck surface. The theory is applied to the problem of filling an n-sided hole occurring within a smooth rectangular patch complex. A number of solutions to this problem are surveyed

High order continuous polygonal patches

A polygonal patch method is described which can be used to fill a polygonal hole within a given k'th order continuous rectangular patch complex. The method is relatively easy to implement, since it only re- quires Ck extensions of the rectangular patch complex defined in terms of the rectangular patch parameterizations. The method is illustrated by reference to C2 bicubic B-spline surfaces

Human oviductal cells and their conditioned medium maintain the motility and hyperactivation of human spermatozoa in vitro

The effects of the co-incubation of human oviductal cells with human spermatozoa on the general motility pattern and hyperactivation of spermatozoa in vitro were studied using computer-assisted sperm analysis. Co-incubation preserved ail the sperm motility parameters, with the exception of the percentage of hyperactivation (HA), beat cross frequency (BCF), and the percentage of transitional hyperactivated (THA) spermatozoa, when compared with the initial motility pattern of the spermatozoa. The HA and THA decreased, and BCF increased after co-incubation for 3 h; these levels then remained stable up to 5 h. The control spermatozoa showed a continuous significant change after 5 h incubation. The oviductal cell-conditioned medium maintained all the motility parameters of spermatozoa even after 5 h incubation. These data suggested that human oviductal cells could maintain the motility of spermatozoa in vitro. Similar effects were also observed when conditioned medium was used to treat subnormal spermatozoa.link_to_subscribed_fulltex

A prospective randomized control study to compare the effect of serum and a commercial serum substitute (Plasmanate) on the outcome of assisted reproduction program

Objectives: To compare the effect of supplementation of serum and Plasmanate, a commercial serum substitute, to culture medium on the IVF outcome. Methods: One hundred eighty-nine subfertile couples were prospective randomized into the serum and the Plasmanate group during their IVF treatment. In vitro experiment was also performed to determine the fraction of Plasmanate that might affect embryo development. Results: The pregnancy rate were similar in both groups. The fertilization rate, the number of gestational sacs and good quality spare embryos suitable for cryopreservation were higher in the serum group than the Plasmanate group. However, these differences did not reach statistical significance. Significantly more embryos in the former cleaved to more than 4 cells at the time of transfer than the latter (p < 0.05). Ultrafiltration study showed that this inhibitory effect resided in the low molecular weight fraction (< 30-kD) of Plasmanate. Conclusions: Serum is slightly better than Plasmanate as a protein supplement. However, Plasmanate may still be used for short term embryo culture in assisted reproduction.link_to_subscribed_fulltex

Embryo cryopreservation: a local experience

Abstrac

Higher education and younger age are associated with better understanding of clinical trials among Hong Kong cancer patients

Conference Theme: New Paradigms in Cancer Prevention, Diagnostics, and Therapie