Enhancement of serotonergic neural activity contributes to cyclosporine-induced tremors in mice

Patients suffering from inflammatory or dysimmunitary diseases may develop various clinical responses to corticotherapy. This brief article describes the various cellular and molecular mechanisms which underly the genetic, endocrine and immunitary factors involved in corticosensitivity, corticoresistance and corticodependence.     

New modifications of poly(vinyl alcohol)s and their applications

Poly(vinyl alcohol) (PV-OH), prepared from poly(viny) acetate), is used widely in many industries. Various grades have been produced, with different degree of polymerization and degree of hydrolysis. Recently, novel modified (PV-OH)s with anion, cation, silanol or hydrophobic groups have been studied and developed. They have new properties in addition to those of ordinary PV-OH and have new applications. The methods of modification and the characteristics and some applications of the modified polymers are described.     

Effective Utilization of Radiation and Two-Color Pyrometers

Existing procedures are standardized and translated into a computer program. Studies were made of charging, blowing and chemical reactions, and the use of flame radiation pyrometry and two-color pyrometry.     

Photoionization cross-sections and energy levels of gold,iron, platinum,silver, and titanium in silicon

The photoionization cross-sections of various deep impurities of interest in solar-grade silicon for photovoltaic cells, and the corresponding energy levels, have been determined by steady state photo-induced currents in pn junctions or Schottky barrier junctions irradiated simultaneously with two wavelengths of light. Light of about half the band-gap energy controls the occupancy of the deep impurity level and the spectral dependence of the photocurrent on a higher photon energy light source then provides, via the Lucovsky model, the photo-cross-section and the impurity energy level. The results obtained for Au and Pt in Si are in agreement with those of Braun and Grimmeiss and the energy levels for Fe, Ti, and Ag obtained optically are in agreement with those obtained by other methods.     

A novel transfection method for mammalian cells using calcium alginate microbeads

The direct transfer of genetic materials into mammalian cells is an indispensable technique. We have developed calcium alginate (CA) microbeads which can deliver plasmid DNAs and yeast artificial chromosomes into plant and yeast cells. In this paper, we demonstrate the effective transfection of mammalian cells by CA microbeads immobilizing plasmid DNAs. The transfection was performed using the pEGFP-C1 plasmid containing the cytomegalovirus (CMV) promoter and enhanced green fluorescent protein (EGFP) gene. The transient expression of EGFP was observed 24 h after transfection. The expression efficiency was maximum when the concentration of sodium alginate was 1% and the amount of plasmid DNA was increased to 100 microg. The expression efficiency of our method using CA microbeads is 2-10 times higher than that of the polyethylene glycol (PEG) method. Our results suggest that the CA microbead mediated transfection of mammalian cells effectively delivers genetic materials into mammalian suspension cells.     

Development of new dosimetry using extended DNA fibers

We applied fluorescent microscopy to monitor the damage of DNA upon exposure to gamma radiation. Our developed dosimetry demonstrated that the number of breaks in DNA is proportional to the dose of the irradiation but is not dependent on dose rate of the irradiation and the GC content of DNA.     

A method for radiation-force localized drug delivery using gas-filled lipospheres

We have developed a method using ultrasound and acoustically active lipospheres (AALs) that might be used to deliver bioactive substances to the vascular endothelium. The AALs consist of a small gas bubble surrounded by a thick oil shell and enclosed by an outermost lipid layer. The AALs are similar to ultrasound contrast agents: they can be nondestructively deflected using ultrasound radiation force, and fragmented with high-intensity ultrasound pulses. The lipid-oil complex might be used to carry bioactive substances at high concentrations. An optimized sequence of ultrasound pulses can deflect the AALs toward a vessel wall then disrupt them, painting their contents across the vascular endothelium. This paper presents results from a series of in vitro and ex vivo experiments demonstrating localization of a fluorescent model drug. In experiments using a human melanoma cell (A2085) monolayer, a specific radiation force-fragmentation ultrasound pulse sequence increased cell fluorescence more than 10-fold over no ultrasound or fragmentation pulses alone, and by 50% over radiation force pulses alone. We observe that dye transfer is limited to cells that are in the region of ultrasonic focus, indicating that the application of radiation force pulses to bring the delivery vehicle into proximity with the cell is required for successful adhesion of the vehicle fragments to the cell membrane. We also demonstrate dye transfer from flowing AALs, both in a mimetic vessel and in excised rat cecum. We believe that this method could be successfully used for drug delivery in vivo.     

Elasto-plastic analysis of orthogonally stiffened plates with initial imperfections under uniaxial compression

In general, the stiffened plates consisting of steel plate elements are unavoidably accompanied by initial imperfections such as residual stresses and initial deflections, which have considerable effects on their ultimate strength. Therefore, it is needed for designing them to develop more rational method taking the ultimate strength influenced by initial imperfections into account rather than the conventional design method being on the basis of the linear elastic buckling theory.From this point of view, this study aims to evaluate rigorously the ultimate strength of orthogonally stiffened plate with initial imperfections under uniaxial in-plane compression. The elasto-plastic finite element method is applied to attain this purpose. By a happy combination of modal analytical technique and conventional finite element method, much reduction of the degree of freedom can be expected to be realized herewith. Some numerical calculations are performed by means of this rigorous method to examine the exactness of the analysis. Moreover, the numerical results are compared with the experimental ones.     

Inverse scattering for a three-dimensional object in the time domain

An iterative inverse-scattering approach to reconstruction of electrical parameter distributions of a three-dimensional object by using time-domain field data is presented. The approach is the extension of the forward-backward time-stepping algorithm previously proposed for a two-dimensional object. Numerical examples of simulation data are given to assess the effectiveness of the proposed approach.     

A novel anionic surfactant templating route for synthesizing mesoporous silica with unique structure

Anionic surfactants are used in greater volume than any other surfactants because of their highly potent detergency and low cost of manufacture. However, they have not been used as templates for synthesizing mesoporous silica. Here we show a templating route for preparing mesoporous silicas based on self-assembly of anionic surfactants and inorganic precursors. We use aminosilane or quaternized aminosilane as co-structure-directing agent (CSDA), which is different from previous pathways. The alkoxysilane site of CSDA is co-condensed with inorganic precursors; the ammonium site of CSDA, attached to silicon atoms incorporated into the wall, electrostatically interacts with the anionic surfactants to produce well-ordered anionic-surfactant-templated mesoporous silicas (AMS). These have new structures with periodic modulations as well as two-dimensional hexagonal and lamellar phases. The periodic modulations may be caused by the coexistence of micelles that differ in size or curvature, possibly owing to local chirality. These mesoporous silicas provide a new family of mesoporous materials as well as shedding light on the structural behaviour of anionic surfactants.