Transient cell proliferation with polyethylenimine-cationized N-terminal domain of simian virus 40 large T-antigen

Polyethylenimine (PEI) cationization is a powerful strategy for protein transduction into cells. In this study, we attempted the artificial regulation of cell proliferation by protein transduction of the N-terminal domain (1-132 amino acids) of the simian virus 40 large T-antigen (SVLT-N), which inactivates retinoblastoma family proteins but not p53. To deliver SVLT-N into cells, we employed an indirect cationization method by forming a complex of biotynylated SVLT-N through disulfide bonds (biotin-SS-SVLT-N) and PEI-cationized avidin (PEI600-avidin). Using this complex, SVLT-N was transduced into the nucleus of confluent and quiescent Balb/c 3T3 cells and was found to be complexed with a cellular target protein, pRb. Furthermore, SVLT-N transduction induced cell proliferation in spite of confluent conditions. Because SVLT-N thus transduced into cells gradually degraded and was not detectable after a 4-d incubation, transiently transformed cells were obtained by this method. These results suggest that oncogene protein transduction technology has great potential for in vitro regulation of cell proliferation.     

快速凝固Fe-C-Si-Mo合金的晶化行为与硬度SCIEI

本文用单辊法制备了Fe-C-Si-Mo合金快速凝固薄带.研究了Fe-C-Si-Mo合金快速凝固薄带的晶化行为、相组成变化和硬度变化规律.经热处理后,该合金具有很高的Vickers硬度值,X射线衍射和SEM分析表明,硬度的提高是由于晶化时形成大量尺寸很小的碳化物。     

Force dispersion and shock damping mediated by close-packed arrays of distally connected cells

Though current materials developed to prevent damage to goods and/or pain and injury to human limbs actually absorb relatively little and disperse virtually no energy in confined spaces, we still primarily rely upon the limited physical properties of such conventional protective materials. New structures (that consist of arrayed cells which are pressurized with fluid and interconnected with distant cells via channels) have been shown to efficiently disperse force and damp shock. A series of experiments demonstrated that when dynamic force was applied to the tops of these structures, the dispersion mechanism of the structure resulted in a markedly decreased maximum pressure at the bottom surface as well as a gradual rather than sudden increase of the pressure which remained. The maximum pressure is reduced by at least a factor of ten over that of conventional “bubble packaging-like” material. A theoretical analysis of dynamic energy dispersion is also provided, which accounts for flow resistance in channels and agrees well with the experimental results.     

Manipulating the chemical affinity and kinetics of 3D silica particle network via the phase-separation technique

We developed a simple and versatile technique for a particle’s self-organizing-network based on a non-solvent induced micro-phase separation (NIPS). When a good solvent vaporizes from a particle dispersion in a ternary solution including the polymer, good solvent and non-solvent, the suspension is separated into the polymer network and non-solvent phase. If the affinity between the particles and polymer is sufficient enough, the particles are entrapped in the polymer network and particle network can be achieved. To expand this technique to particles with various physical properties, the surface of the particles was identified using the Hansen dispersibility parameter (HDP). From a comparison of the HDP of the unmodified and modified silica, an NH₂ group is suitable for entrapment of the silica by cellulose acetate as the polymer. However, with an increase in number of the silica particles, entrapment of the silica in the polymer was prevented. Control of the phase separation rate by the lowering temperature leaded to entrapment of silica particles in the polymer network. The proposed technique is effective not only for spherical oxide particles, but also for non-oxides, various shapes and structures. Depending on particle characteristics, functional films and bulk materials for thermal insulation, light diffusion, and electro conductivity can be obtained.     

Effect of additives on the renaturation of reduced lysozyme in the presence of 4 M urea

Reduced lysozyme was renatured by sulfhydryl-disuffide interchangereactions at pH 8.0 in the presence of 4 M urea, with or withoutadditives at 40°C. In the absence of additives, the finalfolding yield of reduced lysozyme was 40%. In the presence ofsarcosine, glycerol, ammonium sulfate, N-acetyl glucosamineand glucose, its folding yields increased in all cases. In particular,yields increased up to 90% in the presence of 4 M sarcosine.On the other hand, the melting temperatures of lysozyme withor without additives in 0.02 M citrate buffer (pH 6.0) wereevaluated using differential scanning calorimetry. In the absenceof additive, the melting temperature of lysozyme was 73.8°C.In the presence of additives, all melting temperatures werehigher than that of lysozyme in the absence of additives. Moreover,there was a good correlation on addition of additives betweenan increase in the folding yield of reduced lysozyme with 4M urea and an increase in the melting temperature without 4M urea. Therefore, we conclude that additives, which stabilizenative lysozyme, are effective at increasing the folding yieldof reduced lysozyme in 4 M urea.     

Effect of crystallization temperature of palm oil on its crystallization. IV. The influence of tripalmitoylglycerol (PPP) on the crystallization of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP) and 1,2-dioleoyl-3-palmitoyl-glycerol (POO)

Triacylglycerin in Palm Oil contains POP (1,3-dipalmitoyl-2-oleoyl-glycerol) at 30%, POO (1,2-dioleoyl-3-palmitoyl-glycerol) at 20% and PPP (tripalmitoylglycerol) at 5%. The crystallization temperature of PPP is high and the rates of crystal nuclear formation and growth are fast. It is thus considered that PPP may have some effect on the manner or mode of Palm Oil. Examination was thus made to clarify how PPP may affect the crystallization of POP and POO by differential scanning calorimetry (DSC) and X ray diffractometry (XRD) conducted on PPP/POP and PPP/POO mixtures. High and low temperature peaks were noted to appear on the DSC crystallization curve for either of these mixtures. The high temperature peak was considered possibly due to PPP, and the low temperature peak, to POP or POO. DSC isothermal analysis indicated the rate of crystal growth of either mixture to exceed that of pure of POP or POO. Crystal mixture structure was also seen to be complicated than either compound in pure form. The present findings thus clearly indicate that clarification should be made of the effects of high melting point triacylglycerin, such as PPP, on the crystallization of Palm Oil.     

Fusion and molecular aspects of liposomal nanocarriers incorporated with isoprenoids

The present study was conducted to investigate whether typical isoprenyl compounds (TICs) can control liposomal fusion reactions through changes in the physical properties of membranes. The fusion capabilities of TIC-incorporated liposomes were characterized by measuring the 13C spin-lattice relaxation times (13CT1) and the gel permeation chromatogram (GPC) patterns. The 13CT1 relaxivities of some of these TIC-liposomes were remarkably enhanced at 27 degrees C. The highest 13CT1 value obtained was for the beta-carotene-liposome, which ruptured, and was attributed to the highest membrane fusion reactivity. The other TIC-liposomes incorporated with alpha-tocopherol, canthaxanthin, or coenzyme Q10 also induced significant fusion and did not rupture in comparison with the beta-carotene-liposome. These results show that the incorporations of TICs into lipid bilayers are useful to control liposomal nanocarriers for suitable membrane packing and advantageous phase separation, which could affect membrane-related processes.     

Micro inspection robot for 1-in pipes

A micro inspection robot for 1-in pipes has been developed. The robot is 23 mm in diameter and 110 mm in length and is equipped with a high-quality micro charge-coupled device (CCD) camera and a dual hand for manipulating small objects in pipes. It can travel through both vertical pipes and curved sections, making possible inspections that would be difficult with conventional endoscopes. Its rate of travel is 6 mm/s and it has a load-pulling power of 1 N. To realize this microrobot, the authors have specially designed and developed several micro devices and micromechanisms: a novel micromechanism called a planetary wheel mechanism for robot drive; a micro electromagnetic motor with a micro planetary reduction gear to drive the planetary wheel mechanism; a micro pneumatic rubber actuator that acts as a hand; a micro CCD camera with high resolution; and a pneumatic wobble motor for rotating the camera and hands. In the paper, the design and performance of these micro devices are reported, the performance of the robot as a whole is described, and an application example is given     

ESR studies of the effect of zeolite structures on motional dynamics of NO2

Electron spin resonance (ESR) spectroscopy was used to study the effect of zeolite structure on the motional dynamics of NO₂ adsorbed on the zeolites. The temperature-dependent ESR spectral line shapes were quantitatively analyzed using the slow-motion ESR theory. It was observed that the motional dynamics of NO₂ is strongly dependent on the structure of the zeolite (Beta-type, ZSM-5, mordenite, L-type and ferrierite zeolites). The following important observations were made. (1) In zeolites with similar channel structures, the diffusion rate of NO₂ is proportional to the channel size, and the order of the diffusion rates is Beta-type>ZSM-5>ferrierite and L-type>mordenite. (2) The diffusion of NO₂ is faster in the zeolites with multi-dimensional channels (Beta-type, ZSM-5 and ferrierite) than that in those with uni-dimensional channels (L-type and mordenite).     

Pollution control of actual flue gas using pulsed power at a thermal power plant

There are several important environmental problems in the world. One of them is acid rain caused by combustion flue gases from thermal power plants, factories, and automobiles. Different kinds of gas discharges, such as surface discharge, dc and ac corona discharge, silent discharge, and electron beam controlled discharge, have been studied for the removal of NO_x and SO₂ from flue gases. The recent development of repetitive pulsed power generators gives the pulsed steamer corona discharges a chance of success in the removal of NO_x and SO₂. In this paper, the experimental results of NO_x and SO₂ removal by a repetitive pulse power generator are described. The actual flue gas at a thermal power plant was used. It is shown that about 90% of the NO was removed at a flow rate of 0.8 liters/min and a repetition rate of 7 pps. © 2001 Scripta Technica, Electr Eng Jpn, 134(4): 28–35, 2001