Chaperonin-mediated stabilization and ATP-triggered release of semiconductor nanoparticles

Various properties of semiconductor nanoparticles, including photoluminescence and catalytic activity, make these materials attractive for a range of applications. As nanoparticles readily coagulate and so lose their size-dependent properties, shape-persistent three-dimensional stabilizers that enfold nanoparticles have been exploited. However, such wrapping approaches also make the nanoparticles insensitive to external stimuli, and so may limit their application. The chaperonin proteins GroEL (from Escherichia coli) and T.th ('T.th cpn', from Thermus thermophilus HB8) encapsulate denatured proteins inside a cylindrical cavity; after refolding, the encapsulated proteins are released by the action of ATP inducing a conformational change of the cavity. Here we report that GroEL and T.th cpn can also enfold CdS semiconductor nanoparticles, giving them high thermal and chemical stability in aqueous media. Analogous to the biological function of the chaperonins, the nanoparticles can be readily released from the protein cavities by the action of ATP. We expect that integration of such biological mechanisms into materials science will open a door to conceptually new bioresponsive devices.     

Recent Advances in High Efficiency Solar Cells

1 Results The conversion efficiency of sunlight to electricity is limited around 25%,when we use single junction solar cells. In the single junction cells,the major energy losses arise from the spectrum mismatching. When the photons excite carriers with energy well in excess of the bandgap,these excess energies were converted to heat by the rapid thermalization. On the other hand,the light with lower energy than that of the bandgap cannot be absorbed by the semiconductor,resulting in the losses. One way...     

Continued in vitro and in vivo release of an antitumor drug from albumin microspheres

Heated albumin microspheres with an average diameter of 45 +/- 8 microns and containing mitomycin C, released, in vitro, about 20% of this antibiotic over a 3-day period. VX-2 tumors were implanted into the hind leg of rabbits and the drug-containing microspheres were injected into the femoral artery of these animals. High levels of the drug were maintained for several hours in the tumor and growth of the tumor was inhibited considerably, compared to findings in control rabbits given the conventional mitomycin C. Half the number of the rabbits treated with our new method are alive with no evidence of tumor.     

ACTH response induced by interleukin-1 is mediated by CRF secretion stimulated by hypothalamic PGE

Summary We investigated whether hypothalamic prostaglandin E₂ (PGE₂) and corticotropin releasing factor (CRF) are responsible for the development of the adrenocorticotropic hormone (ACTH) response induced by interleukin-1 (IL-1). The present results show that ACTH responses induced by intravenous injection of IL-1 were suppressed by systemic pretreatment with indomethacin and that intrahypothalamic injection of PGE₂ stimulates the secretion of ACTH. Furthermore, systemic pretreatment with anti-CRF antibody significantly suppressed the ACTH response induced by intrahypothalamic injection of PGE₂. These data suggest that the ACTH response induced by IL-1 is mediated by CRF secretion stimulated by hypothalamic PGE₂.     

IT APPLICATIONS PORTFOLIO MANAGEMENT UNDER BUSINESS AND IMPLEMENTATION UNCERTAINTY

Corporations need to improve business processes in order to enhance velocity and service levels while reducing their processing costs and differentiating themselves in the face of competition. The levitation of importance beyond support roles has raised IT investment decisions to high priority in chief executive officers＇ agendas. Corporate planning groups as well as lines of business are increasingly applying techniques of IT applications portfolio management in a more systematic fashion to improve decision-making and resource-allocation processes.
Recent advances in software engineering and IT service delivery methodologies have achieved the logical separation of business functions from implementation. This separation has made a new breed of innovative IT project possible with a new project risk structure; the adjustment of portfolio management techniques is appropriate. We present an integrated portfolio management model so that the corporation can focus on organic growth through sources at both the department and top management levels. The research gives clear advice as to how top management can seek economic growth by selecting an entrepreneurial strategic posture, implying a strong risk-taking propensity. By integrating a risk-return model and risk-tolerance paradigm to cope with today＇s risk structure, overall capabilities can improve the decision process and the corporation＇s performance as well. The application of the integrated technique to a Japanese manufacturing firm is described.     

Observations on calcareous corpuscles using a scanning electron microscope

Summary Calcareous corpuscles were observed in a scanning electron microscope, and the presence of Ca was examined by means of elemental X-ray analysis.     

Expression of functional acetylcholine receptor from cloned cDNAs

The cloned cDNAs encoding the four subunits of the Torpedo californica acetylcholine receptor, each carried by a simian virus 40 vector, direct the synthesis of the functional receptor in a combined expression system consisting of COS monkey cells and Xenopus oocytes. Our results suggest that all four subunits are required to elicit a normal nicotinic response to acetylcholine, whereas only the alpha-subunit is indispensable for alpha-bungarotoxin binding activity.     

MicroRNA control of Nodal signalling

MicroRNAs are crucial modulators of gene expression, yet their involvement as effectors of growth factor signalling is largely unknown. Ligands of the transforming growth factor-beta superfamily are essential for development and adult tissue homeostasis. In early Xenopus embryos, signalling by the transforming growth factor-beta ligand Nodal is crucial for the dorsal induction of the Spemann's organizer. Here we report that Xenopus laevis microRNAs miR-15 and miR-16 restrict the size of the organizer by targeting the Nodal type II receptor Acvr2a. Endogenous miR-15 and miR-16 are ventrally enriched as they are negatively regulated by the dorsal Wnt/beta-catenin pathway. These findings exemplify the relevance of microRNAs as regulators of early embryonic patterning acting at the crossroads of fundamental signalling cascades.