Transfer to a nitrocellulose membrane allows of the bone forming activity of bone morphogenetic protein

When we purify bone morphogenetic protein (BMP), its activity diminishes, and the quantity we are able to extract decreases. It is difficult to evaluate the effects of each of the processes involved in BMP purification because it is unstable. In order to resolve the problem, a modified bioassay method using only slight quantities of BMP which do not decrease its bone-forming activity, is needed. We transferred BMP separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) onto nitrocellulose membranes (NC) and cut out the bands. Then we used each band as implanted material. The NC membrane firmly bound the BMP activity fraction and held it in the implantation area of the mouse thigh. No formation of bone-like tissue was detected histologically at 14 days after the implantation, but, by 21 days after implantation, cartilage like tissue had clearly formed and newly formed bone was seen by 28 days. By implanting BMP transferred to individual NC membranes, we could perform a bioassay easily with small amounts of BMP without any reduction in activity.     

DAD: a real-time expert system for monitoring of data packetnetworks

A project is described that has two goals: to explore the use of expert systems techniques for developing advanced operation support systems and to build a useful tool to assist the operators of the Canadian National Datapac network to cope with the rapid growth and evolution. Progress in developing and evaluating an advanced prototype system, DAD (Datapac Advisor), is reported. The prototype's environment and each of its functional components are described. The knowledge based design techniques used are highlighted, and the testing methodology and the results of a technical trial are described. Key findings are summarized, and their significance for the development of future network operation support systems is discussed     

Measurements of thermal-neutron capture cross-section of Cesium-135 by applying mass spectrometry

ABSTRACT

The thermal-neutron capture cross-section (σ₀) and resonance integral (I₀) were measured for the ¹³⁵Cs(n,γ)¹³⁶Cs reaction by an activation method and mass spectrometry. Because of difficulty in the preparation of pure ¹³⁵Cs samples, we used ¹³⁵Cs contained as an impurity in a normally available ¹³⁷Cs standard solution. An isotope ratio of ¹³⁵Cs and ¹³⁷Cs in a standard ¹³⁷Cs solution was measured by mass spectrometry to quantify ¹³⁵Cs. Cesium-135 impurity along with the ¹³⁷Cs standard solution was irradiated at the hydraulic conveyer of the research reactor in the Institute for Integral Radiation and Nuclear Science, Kyoto University. Wires of Co/Al and Au/Al alloys were used as neutron monitors to measure thermal-neutron fluxes and epi-thermal Westcott’s indices at an irradiation position. A gadolinium filter was used to measure the σ₀, and a value of 0.133 eV was taken as the cut-off energy. Gamma-ray spectroscopy was used to measure induced activities of ¹³⁷Cs, ¹³⁶Cs and monitor wires. On the basis of Westcott’s convention, the σ₀ and I₀ values were derived as 8.57 ± 0.25 barn, and 45.3 ± 3.2 barn, respectively. The value of σ₀ obtained in the present study agreed within the limits of uncertainties with the past-reported value of 8.3 ± 0.3 barn.     

Determination of mercury levels in biological samples using the incomplete cubane-type sulfur-bridged nitrilotriacetato molybdenum complex by a spectrophotometer

Spectrophotometric determination of mercury levels in biological samples was investigated using incomplete cubane-type sulfur-bridged molybdenum complex, K2[Mo3S4(Hnta)3] 9H2O, ("NTA" complex; H3nta = nitrilotri acetic acid). The urine or organs of mice, which were either exposed to metallic mercury vapor or injected intraperitoneally with mercuric ion, were decomposed from four to twelve hours with a mixed solution of potassium permanganate and sulfuric acid. After the pretreatment, mercury in the urine and organs of mice was captured by the "NTA" complex. Absorbance of the resultant solution in the urine or organs of mice was also measured by a spectrophotometer under conditions similar to that of the exhalation.     

a study of cast alloys with partially dispersed graphite III: Characterization of high density dispersed surfaces

The characteristic features of cast alloys with partially dispersed graphite are wear resistance and toughness. The friction and wear performance, hardness and other surface characteristics of the cast alloys with a high dispersive density of 60% at the casting surfaces were studied.The reciprocating sliding wear volume of aluminium alloy AC7A containing dispersants decreases with an increase in the gravity variable G = 2π²DN²/60²g, where D (cm) is the diameter of rotation, N (rev min^?1) is the rotational speed and g (cm s^?2) is the acceleration due to gravity, but depends on the nature of the dispersants. The effect of casting temperature on the wear loss was not significant. The dispersive density at the near-surface regions which is susceptible to the magnitude of G has a direct effect on the wear loss. A dense dispersant has an adverse effect on wear resistance and lubricity. A relation between surface roughness and casting temperature is also reported.     

An Improved Method for Preparing Dimethyl Disulfide Adducts for GC/MS Analysis

Dimethyl disulfide (DMDS) adducts are prepared from fatty acid methyl esters to locate the double-bond position in monoenoic fatty acids by gas chromatography/mass spectrometry. We improved our original procedure for preparing DMDS adducts with a simple device that can be made in any laboratory using a glass pipette and silica based packing material, Extelut NT.     

Finishing of AT-cut quartz crystal wafer with nanometric thickness uniformity by pulse-modulated atmospheric pressure plasma etching

Quartz resonator is a very important device to generate a clock frequency for information and telecommunication system. Improvement of the productivity of the quartz resonator is always required because a huge amount of the resonator is demanded for installing to various electronic devices. Resonance frequency of the quartz resonator is decided by the thickness of the quartz crystal wafer. Therefore, it is necessary to uniform the thickness distribution of the wafer with nanometric level. We have proposed the improvement technique of the thickness distribution of the quartz crystal wafer by numerically controlled correction using atmospheric pressure plasma which is non-contact and chemical removal technique. Heating effects of the quartz wafer in the removal rate and the correction accuracy were investigated. The heating of the substrate and compensate of the scanning speed of the worktable according to the variation of the surface temperature enabled an increase of 50% in the etching rate and 10-nanometric-level accuracy in the correction of the thickness distribution of the quartz wafer, respectively.     

Limit of gate oxide thickness scaling in MOSFETs due to apparentthreshold voltage fluctuation induced by tunnel leakage current

We report on a new roadblock which will limit the gate oxide thickness scaling of MOSFETs. It is found that statistical distribution of direct tunnel leakage current through 1.2 to 2.8 nm thick gate oxides induces significant fluctuations in the threshold voltage and transconductance when the gate oxide tunnel resistance becomes comparable to gate poly-Si resistance. By calculating the measured tunnel current based on multiple scattering theory, it is shown that the device characteristics fluctuations will be problematic when the gate oxide thickness is scaled down to less than 1 nm     

Relationship between human in-vitro fertilization and intracytoplasmic sperm injection and the zona-free hamster egg penetration test

The zona-free hamster egg penetration test (HEPT) is widely used for evaluating the fertilizing ability of human spermatozoa. However, the relationship between the HEPT and microassisted fertilization has yet to be determined. To evaluate the efficiency of HEPT in selecting the most appropriate method of in-vitro fertilization (IVF), including intracytoplasmic sperm injection (ICSI) in couples with male factor infertility, clinical laboratory data was analysed retrospectively. The patients were divided into groups according to the sperm penetration index as determined by the HEPT: group A (sperm penetration index = 0), group B (sperm penetration index < 15) and group C (sperm penetration index > or = 15). A total of 405 oocytes were collected and inseminated by conventional methods in 69 couples with male factor infertility. In all, 31 out of 148 (20.9%) oocytes fertilized in group A; 35 out of 117 (29.9%) in group B; and 73 of 140 (52.1%) in group C. The clinical pregnancy rates per transfer in groups A, B and C were 0% (0/13), 0% (0/14) and 25.9% (7/27) respectively. Both the fertilization rate and pregnancy rate in group C was significantly higher than in groups A and B. ICSI was carried out in a total of 57 couples and 334 oocytes in metaphase II stage were manipulated. The normal fertilization (2 pronuclear) rate per oocyte was 65.6 +/- 26.0% (mean +/- SD). Out of 127 oocytes, 76 (59.8%) fertilized in group A, 57 out of 87 oocytes (65.5%) in group B and 86 out of 120 oocytes (71.7%) in group C. Of the 56 transfers, 17 clinical pregnancies were obtained, giving an average pregnancy rate of 30.4% per transfer. The clinical pregnancy rates per transfer in groups A, B and C were 17.4% (4/23), 40.0% (4/10) and 39.1% (9/23) respectively. No significant differences were observed in the fertilization rates or in the pregnancy rates between the three groups. In addition, there were no differences in the fertilization and pregnancy rates between the ICSI and IVF patients in group C. These findings suggest that the results of the HEPT are well correlated with the fertilizing ability of human spermatozoa in the patients treated by conventional IVF. Couples suffering from male factor infertility with a sperm penetration index of < 15 (as determined by HEPT) should consider treatment with ICSI, while those with a sperm penetration index of > or = 15 should attempt conventional IVF.