Fluorescence-labeled peptide pI markers for capillary isoelectric focusing

Nineteen fluorescent pH standards or pI markers ranging pH 3.64-10.12 were developed for use in capillary isoelectric focusing using laser-induced fluorescence detection. Tetra- to tridecapeptides containing one cysteine residue were designed to focus sharply at their respective isoelectric points by including amino acids that contain charged side chains, the pKa values of which are close to the corresponding pI values. An iodoacetylated derivative of tetramethylrhodamine was coupled to the thiol group of cysteine to yield fluorescent pI markers. The pI values of the labeled peptides were precisely determined after isoelectric focusing on polyacrylamide gel slabs by direct measurement of the pH of the focused bands. The markers were subjected to capillary isoelectric focusing for 10-15 min in coated capillaries under conditions of low electroosmosis and were detected by means of a scanning laser-induced fluorescence detector down to a level of subpicomolar range. The markers permitted the calibration of a wide-range pH gradient formed in a capillary by fluorescence detection for the first time and should facilitate the development of highly sensitive analytical methods based on a combination of capillary isoelectric focusing and laser-induced fluorescence detection.     

浇注过程中夹杂物运动的数值模拟

利用二维Ｎ－Ｓ方程和夹杂物运动方程对流体的充型过程和夹杂物在型腔内的运动过程、积聚位置进行了数值计算,并结合水力模拟实验验证了计算结果的准确性．结果表明,本数值计算系统能够较好地模拟金属液的充型和夹杂物的运动过程．     

Quantitative analysis of double-stranded DNA amplified by a polymerase chain reaction employing surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) was utilized for the quantitative analysis of double-stranded (ds) DNA amplified by a polymerase chain reaction (PCR). 4?, 6-Diamidino-2-phenylindole dihydrochloride (DAPI), which intercalates into ds-DNA but does not form a complex with single-stranded (ss) DNA, was added to a DNA solution after amplification by PCR. When the solution was mixed, including ds-DNA-DAPI complexes and free DAPI with silver colloid sol, only free DAPI was adsorbed on the colloid surface. The dye on the colloid gave very intense SERS signals with excitation at 514.5 nm, whereas DAPI engaging in the intercalation with ds-DNA did not show any SERS signal. The SERS spectrum of DAPI on the colloid showed a strong band at 1610 cm(-1) due to the C?N stretching mode, and a linear relationship was observed between the peak intensity of the C?N stretching band and the concentration of free DAPI. Therefore one can determine the concentration of free DAPI by the SERS measurement. The more ds-DNA there is in the solution, the less free DAPI there is. Thus it is possible to quantitatively analyze the ds-DNA amplified by PCR indirectly by using SERS. The correlation coefficient between the peak intensity of the C?N stretching band and the concentration of ds-DNA amplified by PCR was calculated to be 0.988 for a concentration range from 0.1 to 1.3 mg/ml.     

Influence of aging heat treatment on mechanical properties of biomedical Ti–Zr based ternary alloys containing niobium

Titanium–zirconium based alloys containing a small amount of niobium were investigated in order to evaluate their possible use as biomedical materials. Zirconium, which belongs to the IVa group, is known to have good corrosion resistance and biocompatibility similar to titanium. As the titanium–zirconium system shows a complete solid solution, a wide variation of alloy design is available and large quantities of solid-solution hardening must be possible. Niobium, having a -phase stabilizing effect, was chosen as a ternary element in order to control desirably the microstructure. There have been no reports which suggest its harm to a living body. The alloys containing 2% or 3% niobium showed the highest hardness value after aging heat treatment at 773 K. In contrast to this, no alteration of hardness was seen in specimens aged at 1073 K. Through conventional X-ray diffractometry and in situ X-ray analysis using a hot stage, -phase precipitation in the A matrix was identified. From the above results, it is concluded that alloys containing 2%–3% niobium are hopeful candidates for new kinds of biomedical alloys, when they are heat treated under suitable conditions. © 1998 Kluwer Academic Publishers     

Robust MPL scheduling considering the number of in-process jobs

A robust scheduling method for max-plus linear systems is proposed. A principal concern in scheduling problems is how to accomplish robustness against external disturbances. To accomplish this, methods based on model predictive control (MPC) have been put forward to control system parameters or control inputs. In this context, we recently proposed a method for indirectly controlling the state variables by utilizing the idea of dead time. The idea imposes constraints for upper bounds of in-processing jobs between facilities, whereas several practical systems also consider the lower bounds. This paper, therefore, considers a modeling and robust scheduling method that takes into account both constraints. A numerical simulation for a transportation system is also presented in order of the method's effectiveness.     

Access concentration detection in click logs to improve mobile Web-IR

Effective ranking algorithms for mobile Web searches are being actively pursued. Due to the peculiar and troublesome properties of mobile contents such as scant text, few outward links, and few input keywords, conventional Web search techniques using bag-of-words ranking functions or link-based algorithms are not good enough for mobile Web searches. Our solution is to use click logs to clarify access-concentrated search results for each query and to utilize the titles and snippets to expand the queries. Many previous works regard the absolute click numbers as the degree of access concentration, but they are strongly biased such that higher-ranked search results are more easily clicked than lower-ranked ones. Therefore, it is considered that only higher-ranked search results are access-concentrated ones and that only terms extracted from them can be used to expand a query. In this paper, we introduce a new measure that is capable of estimating the degree of access concentration. This measure is used to precisely extract access concentration sites from many search results and to expand queries with terms extracted from them. We conducted an experiment using the click logs and data from an actual mobile Web search site. Results obtained show that our proposed method is a more effective way to boost the search precision than using other query expansion methods such as the top K search results or the most-often-clicked search results.     

Mathematical modeling of frogs’ calling behavior and its possible application to artificial life and robotics

This paper theoretically and qualitatively describes the calling behavior of the Japanese tree frog Hyla japonica with a simple model of phase oscillators. Experimental analysis showed that while an isolated single male frog called nearly periodically, two interacting male frogs called periodically but alternately, with little overlap. We model these phenomena as a system of coupled phase oscillators, where each isolated oscillator behaves periodically as a model of the calling of a single frog, and two coupled oscillators show antiphase synchronization, reflecting the alternately calling behavior of two interacting frogs. Then, we extend the model to a system of three coupled oscillators virtually corresponding to three interacting male frogs, and analyse the nonlinear dynamics and the bifurcation. We also discuss the biological meaning of the calling behavior and its possible application to artificial life and robotics. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007