Ultrastructure of immotile spermatozoa obtained from infertile male patients

We sometimes experienced infertile patients whose sperms had no motility but were not stained by Eosin Y. In this paper we report five cases of so-called "immotile spermatozoa". The ultrastructure of sperm tails was examined by transmission electrone microscope (TEM). These cases were selected from the out-patient population who attended infertility clinic of our department. The semen analyses showed that all the cases had sperm motility below 1% and more than 90% of the spermatozoa were proven alive. Family history revealed that one case had an infertile sibling. None of them had situs inversus, bronchiectasis and chronic sinusitis which are classic trias of Kartagener's syndrome. They had no symptoms of upper respiratory tract infection which was caused by the abnormality in the flagella of the respiratory tract. The TEM pictures of sperm tails showed partial deletion of inner dynein arms in two cases, lack of central microtubular doublets (so-called 9 + 0) in two cases and disarrangement of microtubular doublets in one case. For the treatment of these cases there is no effective means but AID. However, the rapid progress of IVF-ET techniques and a report that the spermatozoa from Kartagener's syndrome had showed penetration into eggs encouraged us to think the micromanipulation of spermatozoa with IVF-ET as a hopeful option of the treatment in the near future.     

Unsteady behavior and control of vortices in centrifugal compressor

Two examples of the use of vortex control to reduce noise and enhance the stable operating range of a centrifugal compressor are presented in this paper.In the case of high-flow operation of a centrifugal compressor with a vaned diffuser,a discrete frequency noise induced by interaction between the impeller-discharge flow and the diffuser vane,which appears most notably in the power spectra of the radiated noise,can be reduced using a tapered diffuser vane（TDV） without affecting the performance of the compressor.Twin longitudinal vortices produced by leakage flow passing through the tapered portion of the diffuser vane induce secondary flow in the direction of the blade surface and prevent flow separation from the leading edge of the diffuser.The use of a TDV can effectively reduce both the discrete frequency noise generated by the interaction between the impeller-discharge flow and the diffuser surface and the broadband turbulent noise component.In the case of low-flow operation,a leading-edge vortex（LEV） that forms on the shroud side of the suction surface near the leading edge of the diffuser increases significantly in size and blocks flow in the diffuser passage.The formation of an LEV may adversely affect the performance of the compressor and may cause the diffuser to stall.Using a one-side tapered diffuser vane to suppress the evolution of an LEV,the stable operating range of the compressor can be increased by more than 12 percent,and the pressure-rise characteristics of the compressor can be improved.The results of a supplementary examination of the structure and unsteady behavior of LEVs,conducted by means of detailed numerical simulations,are also presented.     

Thermoelectric properties of porous SiC/C composites

We developed a porous SiC/C composite by oxidizing a SiC/C composite made from a mixed powder of wood charcoal and SiO₂ (32–45 μm) by pulse current sintering at 1600 and 1800 °C under a N₂ atmosphere. The microstructures of the porous SiC/C composites with oxidation and the SiC/C composites without oxidation were analyzed by Raman spectroscopy and scanning electron microscopy (SEM). Raman spectra revealed the disappearance of excess carbon and the presence of β-SiC. The porous microstructure was monitored by SEM observation as a function of the heat treatment temperature. The thermoelectric properties of porous SiC/C composites with oxidation and SiC/C composites without oxidation were investigated by measuring the Seebeck coefficient, the electrical conductivity and thermal conductivity. The Seebeck coefficient of all samples revealed n-type conduction, and the absolute value of the Seebeck coefficient for the porous SiC/C samples with oxidation was much larger than that for the SiC/C samples without oxidation. For the electrical conductivity the reverse is true. Only the thermal conductivity of the SiC/C sample heated to 1800 °C without oxidation was high initially and stayed rather high. In general, the thermoelectric properties improved at higher measurement temperatures indicating their suitability for high-temperature thermoelectric conversion. A maximum figure of merit of 2.01×10⁻⁵ K⁻¹ was obtained at 700 °C in porous SiC/C samples sintered at 1800 °C with oxidation.     

The effectiveness of interferon therapy on occurrence of hepatocellular carcinoma in chronic hepatitis C

To clarify the effect of interferon (IFN) therapy for chronic hepatitis C (CHC) on the occurrence of hepatocellular carcinoma (HCC), 149 patients who were observed over a period of five years (mean: 7.6 years) were studied. The C-1 group, 33 patients with complete response to IFN; the C-2 group, 55 patients with no response to IFN; and the C-3 group, 61 patients who did not receive IFN. The occurrence rate of HCC was 0.9%/year/person. In the C-1, C-2 and C-3 groups, the rates were 0%, 0.3%, and 1.6%, respectively. The rate in C-1 + C-2 groups was significantly lower than that of the C-3 group (P<0.05). These data suggest IFN may suppress the occurrence of HCC in CHC.     

Effects of classifier structures and training regimes on integrated segmentation and recognition of handwritten numeral strings

In integrated segmentation and recognition of character strings, the underlying classifier is trained to be resistant to noncharacters. We evaluate the performance of state-of-the-art pattern classifiers of this kind. First, we build a baseline numeral string recognition system with simple but effective presegmentation. The classification scores of the candidate patterns generated by presegmentation are combined to evaluate the segmentation paths and the optimal path is found using the beam search strategy. Three neural classifiers, two discriminative density models, and two support vector classifiers are evaluated. Each classifier has some variations depending on the training strategy: maximum likelihood, discriminative learning both with and without noncharacter samples. The string recognition performances are evaluated on the numeral string images of the NIST special database 19 and the zipcode images of the CEDAR CDROM-1. The results show that noncharacter training is crucial for neural classifiers and support vector classifiers, whereas, for the discriminative density models, the regularization of parameters is important. The string recognition results compare favorably to the best ones reported in the literature though we totally ignored the geometric context. The best results were obtained using a support vector classifier, but the neural classifiers and discriminative density models show better trade-off between accuracy and computational overhead.     

PHoM – a Polyhedral Homotopy Continuation Method for Polynomial Systems

PHoM is a software package in C++ for finding all isolated solutions of polynomial systems using a polyhedral homotopy continuation method. Among three modules constituting the package, the first module StartSystem constructs a family of polyhedral-linear homotopy functions, based on the polyhedral homotopy theory, from input data for a given system of polynomial equations f(x)=0. The second module CMPSc traces the solution curves of the homotopy equations to compute all isolated solutions of f(x)=0. The third module Verify checks whether all isolated solutions of f(x)=0 have been approximated correctly. We describe numerical methods used in each module and the usage of the package. Numerical results to demonstrate the performance of PHoM include some large polynomial systems that have not been solved previously.AMS Subject Classification: Primary: 65H10 system of equations, secondary: 65H20 global methods, including homotopy approaches.     

Load dependence of sticking-domain distribution in two-dimensional atomic scale friction of NaF(100) surface

Remarkable transitions were found in atomic-scale friction-images of the NaF(100) surface and the corresponding sticking-domain distribution by detailed investigation of the load dependence using the two-dimensional frictional force microscope. The tip-position map reveals a new type of sticking-domain distribution pattern, which is different from the simple lattice periodicity.