A novel tumor-related protein, C7orf24, identified by proteome differential display of bladder urothelial carcinoma

Proteome analysis of bladder cancer with narrow-range pH 2-DE has identified a novel protein on chromosome 7 encoded by ORF 24 (C7orf24) as one of the highly expressed proteins in cancer cells. C7orf24 is currently registered in the protein database as a hypothetical protein with unknown function. The homologs of C7orf24 in other animals have also been registered as putative protein genes. Western blot analysis using a mAb against C7orf24 confirmed its higher expression in bladder cancer compared with normal tissue. Several other cancer cell lines were also found to express C7orf24. However, the introduction of C7orf24 into Rat-1 or NIH3T3 cells did not cause malignant transformation. A stable transfectant of NIH3T3 cells with recombinant retrovirus vector was produced for a growth rate assay, and a higher growth rate was observed in C7orf24-expressing cells compared with the controls. Six kinds of small interfering RNAs (siRNAs) were then produced, and C7orf24-siRNA#5 showed a strong knockdown effect on protein expression and significant antiproliferative effects on cancer cell lines were demonstrated by the MTT assay. Therefore, C7orf24 may have an important role in cancer cell proliferation, and may be an appropriate therapeutic target molecule against cancer.     

Multistrategy Discovery and Detection of Novice Programmer Errors

Detecting and diagnosing errors in novice behavior is an important student modeling task. In this paper, we describe MEDD, an unsupervised incremental multistrategy system for the discovery of classes of errors from, and their detection in, novice programs. Experimental results show that MEDD can effectively detect and discover misconceptions and other knowledge-level errors that underlie novice Prolog programs, even when multiple errors are enmeshed together in a single program, and when the programs are presented to MEDD in a different order.     

Two-step formation of entanglement from disentangled polymer melt detected by using nucleation rate

“How do chain molecules spontaneously entangle from completely disentangled polymer melt?” remains the most interesting unsolved problem. In order to solve this problem, we used the concept that the melt of “nascent” polymer crystallized during polymerization just after melting does not include any entanglements. We succeeded in detecting the increase of entanglement density ν_e with the increase of annealing time Δt above the equilibrium melting temperature before isothermal crystallization. The increase of ν_e was detected by observing the decrease of nucleation rate I from the melt of nascent polymer with different Δts. I is a very sensitive detector of entanglements because the nucleation is a rearrangement process of chains to the crystalline lattice through the disentanglement. Therefore, I is significantly suppressed with the increase of ν_e. We found a two-step decrease of I with an increase of Δt for the first time. This should correspond to a two-step increase of ν_e with an increase of Δt. This indicates that simple entanglements such as twist or knot with lower order (one time knot) were formed within short time and then the complicated ones such as knot with higher order (two or three times knots) or loops (entanglements by loop conformation) were formed.     

Effect of gel on crystallization behavior of natural rubber after accelerated storage hardening test

Crystallization of natural rubber (NR) and purified NR after storage hardening of the rubbers under dried condition with phosphorus pentoxide was investigated by dilatometry and polarized light microscopy. The purified NR was prepared by removing proteins and fatty acid ester groups from fresh NR (FNR) through deproteinization and transesterification, respectively. The rubbers were characterized in regard as gel content, ester content and crosslink density. Nucleation (I) and growth rates (V) of the gel fraction estimated from the number of spherulites and their sizes observed in the course of isothermal crystallization depended on supercooling (ΔT = T_m⁰ ? T). T_m⁰ is equilibrium melting temperature and T is absolute temperature. Slope of linear line in a plot of logarithmic V versus 1/TΔT for NR was independent of time for storage hardening, suggesting that the lateral surface free energy and diffusion were little function of branching and crosslinking. The rate of crystallization of FNR significantly decreased when the crosslink density increased. Since the overall crystallization is functions of chain mobility and surface free energy, the slower crystallization of well crosslinked FNR may be attributed to the less chain mobility and small value of Δσ due to the formation of crosslinked and branched entities. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Enhanced contractile force generation by artificial skeletal muscle tissues using IGF-I gene-engineered myoblast cells

The aim of this study was to investigate whether insulin-like growth factor (IGF)-I gene delivery to myoblast cells promotes the contractile force generated by hydrogel-based tissue-engineered skeletal muscles in vitro. Two retroviral vectors allowing doxycycline (Dox)-inducible expression of the IGF-I gene were transduced into mouse myoblast C2C12 cells to evaluate the effects of IGF-I gene expression on these cells. IGF-I gene expression stimulated the proliferation of C2C12 cells, and a significant increase in the growth rate was observed for IGF-I-transduced C2C12 cells with Dox addition, designated C2C12/IGF (Dox+) cells. Quantitative morphometric analyses showed that the myotubes induced from C2C12/IGF (Dox+) cells had a larger area and a greater width than control myotubes induced from normal C2C12 cells. Artificial skeletal muscle tissues were prepared from the respective cells using hydrogels composed of type I collagen and Matrigel. Western blot analyses revealed that the C2C12/IGF (Dox+) tissue constructs showed activation of a skeletal muscle hypertrophy marker (Akt) and enhanced expression of muscle-specific markers (myogenin, myosin heavy chain and tropomyosin). Moreover, the creatine kinase activity was increased in the C2C12/IGF (Dox+) tissue constructs. The C2C12/IGF (Dox+) tissue constructs contracted in response to electrical pulses, and generated a significantly higher physical force than the control C2C12 tissue constructs. These findings indicate that IGF-I gene transfer has the potential to yield functional skeletal muscle substitutes that are capable of in vivo restoration of the load-bearing function of injured muscle or acting as in vitro electrically-controlled bio-actuators.     

Quantum Hopfield Network Using Single-Electron Circuits—A Novel Hopfield Network Free from the Local-Minimum Difficulty

The concept of the quantum Hopfield network is proposed with examples of its network construction, which uses single-electron circuits. In this network, two or more threshold elements can change their outputs simultaneously in a form of coherent combination. This can be put into physical form by utilizing the co-tunneling phenomenon found in single-electron circuits. In the quantum Hopfield network, a state transition with a large Hamming distance can occur and therefore the local-minimum difficulty disappears; in consequence the global-minimum energy state can always be achieved. Use of this property made possible the development of novel computation devices that solve combinatorial problems without hindrance from the local-minimum difficulty.     

Static thrust analysis of a cylindrical moving-core linear oscillatory actuator

This paper considers materials for the movers, the volume ratio of the stator and of the mover, and the structure of the mover in a cylindrical moving iron-type linear oscillatory actuator (LOA) having a permanent magnet. As a result, we obtain the following:

• (1) the static thrust characteristics are evaluated on two movers: movers P and S are made of a permendur and a stainless steel, respectively. It is clarified that the static thrust of the mover P is 30 percent larger than that of the mover S;
• (2) it is suggested that the structure of the mover P should be improved to eliminate a “lump” in the static thrust-displacement curve due to the step on the mover, and which disturbs the smooth motion of the LOA.

     

A Capillary Tube Viscometer Designed for Measurements of Hydrogen Gas Viscosity at High Pressure and High Temperature

A capillary tube viscometer was developed to measure the dynamic viscosity of gases for high pressure and high temperature. The apparatus is simple and designed for safe-handling operation. The gas was supplied to the capillary tube from a high-pressure reservoir tank through a pressure regulator unit to maintain a steady state flow. The measurements of a pressure drop across the capillary tube with high accuracy under extreme conditions are the main challenge for this method. A differential pressure sensor for high pressures up to 100 MPa is not available commercially. Therefore, a pair of accurate absolute pressure transducers was used as a differential pressure sensor. Then the pressure drop was calculated by subtracting the outlet pressure from the inlet one with a resolution of 100 Pa at 100 MPa. The accuracy of the present measurement system is confirmed by measuring the viscosity of nitrogen as a reference gas. The apparatus provided viscosities of nitrogen from ambient temperature to 500 K and hydrogen from ambient temperature to 400 K and for pressures up to 100 MPa with a maximum deviation of 2.2 % compared with a correlation developed by the present authors and with REFPROP (NIST).     

Excitation Energy Evolution of Red-Luminescence Band in Porous Si

The excitation energy dependence of red-luminescence spectrum of porous Si prepared in different conditions is investigated in detail. The dependence has shown that the luminescence peak energy E_L of the porous Si nanoparticle is related to the bandgap E_g by E_L = 0.65 E_g+0.44 (eV). The relation has been explained from the model that holes in the Si nanoparticles excited by the interband excitation are trapped and then radiatively recombine with electrons in the conduction band.     

Cloning and characterization of an n-alkane-inducible cytochrome P450 gene essential for n-decane assimilation by Yarrowia lipolytica

A gene encoding cytochrome P450 involved in n-alkane utilization was cloned from an n-alkane assimilating yeast, Yarrowia lipolytica CX161-1B. The RT-PCR was performed on the mRNA prepared from the cells grown on n-alkane as a template using degenerated PCR primers designed for the conserved amino acid sequences of the CYP52 family. The RT-PCR amplified fragment was then used as a probe to isolate genes coding for P450 of the CYP52 family from the genomic DNA library of the strain CX161-1B. The nucleotide sequence of one of the positive clones was determined. An open reading frame which had the same nucleotide sequence as the RT-PCR-amplified fragment was identified. It was of 523 amino acid residues, 60·2 kDa in molecular mass, and had 30–45% sequence identity with the other members of the CYP52 family of Candida species so far analysed. The expression of the P450 gene that was named as YlALK1 was induced by n-tetradecane and repressed by glycerol. A YlALK1 gene disruptant did not grow well on n-decane, but grew on longer-chain n-alkanes such as hexadecane as a sole carbon source. Introduction of YlALK1 on a plasmid to the disruptant restored the decane assimilation. These results suggest that the YlALK1 gene product is the major P450Alk to metabolize short-chain n-alkanes such as decane and dodecane in Y. lipolytica. © 1998 John Wiley & Sons, Ltd.