Pre-treatment of sperm reduces success of ICSI in the pig

In pigs, although ICSI is a feasible fertilization technique, its efficiency is low. In general, injected pig sperm are insufficient to induce oocyte activation and embryonic development. Pretreatments for disrupting sperm membranes have been applied to improve the fertility of ICSI oocytes; however, we hypothesize that such pretreatment(s) may reduce the ability of the sperm to induce oocyte activation. We first evaluated the effects of sperm pretreatments (sonication (SO) to isolate the sperm heads from the tails, Triton X-100 (TX), and three cycles of repeated freezing/thawing (3×-FT) for disrupting sperm membranes) on the rate of pronucleus (PN) formation after ICSI. We found that oocytes injected with control (whole) sperm had higher rates of PN formation than those obtained after subjecting the sperm to SO, TX, and 3×-FT. The amounts of phospholipase Cζ (PLCζ), which is thought to be the oocyte-activating factor in mammalian sperm, in sperm treated by each method was significantly lower than that in whole untreated sperm. Furthermore, using immunofluorescence, it was found that in pig sperm, PLCζ was localized to both the post-acrosomal region and the tail area. Thus we demonstrated for the first time that sperm pretreatment leads to a reduction of oocyte-activating capacity. Our data also show that in addition to its expected localization to the sperm head, PLCζ is also localized in the tail of pig sperm, thus raising the possibility that injection of whole sperm may be required to attain successful activation in pigs.     

Optical control of edge chirality in graphene

We performed optical annealing experiments at the edges of nanopatterned graphene to study the resultant edge reconstruction. The lithographic patterning direction was orthogonal to a zigzag edge. μ-Raman spectroscopy shows an increase in the polarization contrast of the G band as a function of annealing time. Furthermore, transport measurements reveal a 50% increase of the GNR energy gap after optical exposure, consistent with an increased percentage of armchair segments. These results suggest that edge chirality of graphene devices can be optically purified post electron beam lithography, thereby enabling the realization of chiral graphene nanoribbons and heterostructures.     

Development of transient stability controller system (TSC) based on on-line stability calculation

A new transient stability controller system (TSC) based on on-line transient stability calculation has been developed. The TSC system prevents the power system from wide-area blackout by shedding generators optimally when a serious fault occurs. This system consists of a central processing unit (TSC-P), and four local units for fault detection (TSC-C), and seventeen units for generator shedding (TSC-T). The TSC-P selects optimal generators to be shed for stabilization based on on-line transient stability calculation for contingencies at 500 kV lines and buses every five minutes. The results are transmitted to the TSC-Cs periodically. Should any fault occur, only one TSC-C will detect the fault occurrence and send control signals to the TSC-Ts which actually generate shedding signals. To realize the TSC system, essential are fast stability evaluation methods for a large number of contingencies and effective selection methods of optimal generators to be shed for stabilization. This paper presents total algorithms applied in the TSC-P, the results of algorithm verification tests using a prototype system combined with a large-scale analog simulator, and the characteristics of the actual system.     

Shock compaction of NiTi alloy powder

The shock recovery experiment for the equiatomic NiTi alloy powder was performed by the flyer impact technique. The powder samples with the initial density of 70% of full density were shock-treated in the dyer velocity range 0.65 to 1.7 km sec^?1. At the optimum flyer velocity of 1.3 km sec^?1, the powder sample is compacted up to 99.5% of the full density. With increasing flyer velocity, new pores are formed in the melted layer instead of the disappearance of initial interstices. Effects of the mechanical deformation and the annealing brought by the shock treatment evidently appear in the temperature dependence of electrical resistivity accompanied with the martensitic transformation. The shock state and the relaxation of the heterogeneous temperature by the shock treatment are estimated, which indicate the annealing condition caused by shock-loading and the formation of new pores.     

Optimal planning for introducing dispersed generating sources in power systems based on an economical viewpoint

This paper discusses optimal planning problems for dispersed generating sources so as to provide a guideline for their introduction to power systems. First, a recursive method is developed from the viewpoint of supplying electric power only where solutions for one unit are superposed. The computational loads are decreased by selecting alternatives of buses based on the so-called penalty factor. However, for effective utilization of dispersed generating sources, it is indispensable to consider their thermal merits in addition to electric power. After applying the Kuhn-Tucker theory to the optimal dispatching problem including boiler fuel costs, thermal values of the dispersed generating units are evaluated quantitatively. Finally, the above-mentioned technique for the optimal planning basically is also effective and is extended into this case. The validity of the proposed algorithms are demonstrated using a real-scale model system.     

The effect of syndiotacticity of the structure and properties of dehydrochlorinated poly(vinyl chloride) films

The dehydrochlorination of a syndiotacticity-enriched poly(vinyl chloride) (s-PVC) gave polyene materials and the structure and properties of dehydrochlorinated specimens were studied. The results were compared with those obtained for polyene materials formed from a commercial poly(vinyl chloride) (c-PVC). The crystallinity of the s-PVC was higher than that of the c-PVC as revealed by the infrared analysis and X-ray diffraction studies. The dehydrochlorinated specimens from the s-PVC were crystalline to some extent while those from the c-PVC were amorphous. The molecular orientation in the original films was preserved in the dehydrochlorinated specimens. The polyene films from the s-PVC had larger conductivities and showed better doping properties as compared with those from the c-PVC. These results were explained in terms of the larger crystallinity and the increased structural regularity of the s-PVC as compared with those of the c-PVC.     

Integrity of public telecommunications networks

Provides an overview of the special issue of the IEEE Journal of Communications, Volume 12, Number 1 (January 1994) which addresses open questions in network integrity, reliability and survivability. Current progress in this area is discussed. The questions addressed include user survivability perspectives on standards, planning, and deployment; the analysis and quantification of network disasters; survivable and fault-tolerant network architectures and associated economic analyses; and techniques to handle network restoration as a result of physical damage or failures in software and control systems. Special interests are devoted to the survivability of broadband networks employing the new transport/switching techniques based on the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards due to their emerging role in future B-ISDN. Network integrity due to failures of common channel signaling (CCS) systems is also very critical. The present special issue includes 22 papers and is organized into the following sections: user perspectives and planning, software quality and reliability, network survivability characterization and standards, network restoration for SONET networks, network restoration for ATM networks, traffic effect and performance enhancement for computer networks, and survivable network design methods. Network restoration methods for SONET, ATM, and computer networks correspond to those for the physical layer (SONET), ATM layer, and the network layer, defined in the CCITT broadband ISDN layer structure