Stability of the TAR RNA and its complex with arginine

Most stable secondary structures and their stabilization energies of the TAR RNA with +1 to +104 nucleotide-sequence region were calculated at different temperatures by using thermodynamic parameters for RNA structure prediction. The most stable secondary structure has one bulge and one loop within the region of +20 to +40 nucleotide sequence, and its stabilization energy at 37 degrees C was -46.3 kcal mol-1. The interaction of a TAR bulge oligomer (TARBO) with arginine (Arg) which was in the binding site of a Tat protein was also investigated by CD measurements. The addition of Arg did not affect the CD spectrum of TARBO. The result was different from that of the RNA oligomer with both bulge and loop.     

Sintering Kinetics at Constant Rates of Heating: Effect of Al2O3 on the Initial Sintering Stage of Fine Zirconia Powder

The sinterabilities of fine zirconia powders including 5 mass% Y₂O₃ were investigated, with emphasis on the effect of Al₂O₃ at the initial sintering stage. The shrinkage of powder compact was measured under constant rates of heating (CRH). The powder compact including a small amount of Al₂O₃ increased the densification rate with elevating temperature. The activation energies at the initial stage of sintering were determined by analyzing the densification curves. The activation energy of powder compact including Al₂O₃ was lower than that of a powder compact without Al₂O₃. The diffusion mechanisms at the initial sintering stage were determined using the new analytical equation applied for CRH techniques. This analysis exhibited that Al₂O₃ included in a powder compact changed the diffusion mechanism from grain boundary to volume diffusions (VD). Therefore, it is concluded that the effect of Al₂O₃ enhanced the densification rate because of decrease in the activation energy of VD at the initial sintering stage.     

Liquid crystalline side-chain polysiloxanes containing mesogenic groups attached by esterification

Summary Liquid crystalline side-chain polysiloxanes were prepared without metal complex catalyst. Mesogenic groups such as cholesteryl, 4-cyano-4-biphenyl and 4-methoxy-4-biphenyl group were introduced into polysiloxane by esterification and from DSC measurements they were compatible with other liquid crystalline polysiloxanes reported previously.     

Digital watermarking by a holographic technique

A holographic technique is applied for digital watermarking by a computer. A digital-watermark image to be hidden is phase modulated in a random fashion, and its Fourier-transformed hologram is superposed on a content image. The watermark is reconstructed by means of a holographic-reconstruction technique from the bit-map image that hides it. In the study the processes of constructing and reconstructing a digital hologram are described on the basis of the theory of Fourier optics. The conditions for superposing the hologram onto the content images are investigated in detail. The validity of the present method is verified by changing the weighting of the hologram relative to that of the content image. The effect of image size is also discussed with respect to reconstruction of the watermark, and it is shown that watermark information in a form of a diffuse-type Fourier-transform hologram cannot be removed by cutting it out of the host image.     

Synthesis and Thermal Characterization of Novel Poly(tetramethylsilanthrylenesiloxane) and Poly(tetramethylsilphenanthrylenesiloxane) Derivatives

Summary Novel poly(tetramethylsilarylenesiloxane) derivatives, i.e. poly(tetramethyl-2,6-silanthrylenesiloxane) (P1), poly(tetramethyl-9,10-silanthrylenesiloxane) (P2), and poly(tetramethyl-1,8-silphenanthrylenesiloxane) (P3), were synthesized by polycondensation of novel disilanol monomers, i.e. 2,6-bis(dimethylhydroxysilyl)-anthracene (M1), 9,10-bis(dimethylhydroxysilyl)anthracene (M2), and 1,8-bis(dimethylhydroxysilyl)phenanthrene (M3), respectively. P1 and P3 were soluble in common organic solvents, such as benzene, toluene, chloroform, dichloromethane, tetrahydrofuran, etc. whereas P2 was almost insoluble in common organic solvents. It was revealed that P1 and P3 were amorphous and that P2 exhibited the crystallinity, as deduced from differential scanning calorimetry (DSC) and X-ray diffraction measurements. The glass transition temperatures (T_g’s) of P1 (118 °C) and P3 (100 °C) were much higher than that of poly(tetramethyl-1,4-silphenylenesiloxane). The temperature at 5% weight loss (T_d5) of P3 was 500 °C, which was higher than those of P1 and P2, and comparable to that of poly(tetramethyl-1,4-silphenylenesiloxane). It would be speculated that the thermostability of the series of poly(tetramethyl-silarylenesiloxane) derivatives is dependent on the stability of arylene moieties incorporated.     

Dose finding study of cefepime for chronic respiratory infections]

In order to determine the optimal dose of cefepime (CFPM) for respiratory tract infections, a dose finding study was conducted in patients with chronic respiratory tract infections, and the clinical properties of the drugs were compared with those of ceftazidime (CAZ). Each drug was administered by intravenous drip infusion at the dose of 2 g/day of CFPM, 4 g/day of CFPM or 2 g/day of CAZ for 14 days. 1. The overall efficacy rates evaluated by the committee were 82.6% (19/23) for the CFPM 2 g/day group, 85.0% (17/20) for the 4 g/day group and 79.3% (23/29) for the CAZ 2 g/day group, with no statistically significant difference among the three groups. 2. The overall efficacy rates evaluated by the attending physicians were 91.3% (21/23) for the CFPM 2 g/day group, 78.9% (15/19) for the CFPM 4 g/day group and 75.9% (22/29) for the CAZ 2 g/day group, with no significant difference among the three groups. 3. Bacteriological eradication rates were 88.2% (15/17) for the CFPM 2 g/day group, 68.8% (11/16) for the CFPM 4 g/day group and 63.2% (12/19) for the CAZ 2 g/day group, with no statistically significant difference among the three groups. 4. The incidences of adverse reactions were 3.8% (1/26) for the CFPM 2 g/day group, 9.1% (2/22) for the CFPM 4 g/day group and 3.4% (1/29) for the CAZ 2 g/day group, with no significant difference among the three groups. The incidences of abnormal laboratory findings were 37.5% (9/24) for the CFPM 2 g/day group, 15.0% (3/20) for the CFPM 4 g/day group and 3.4% (1/29) for the CAZ 2 g/day group. There was a significant difference among the three groups. 5. Utility rates assessed by the committee were 81.8% (18/22) for the CFPM 2 g/day group, 76.2% (16/21) for the CFPM 4 g/day group and 75.9% (22/29) for the CAZ 2 g/day group. Utility rates assessed by attending physicians were 90.9% (20/22), 78.9% (15/19) and 72.4% (21/29), respectively. There was no significant difference among the three groups. From the above results, it is concluded that the optimal dosage of CFPM is 2 g/day for chronic respiratory tract infections.     

Expression of integrin molecules in sarcoid lesions

In order to assess the role of adhesion molecules in sarcoid lesions, we examined the expression of integrin families and extracellular matrix proteins by immunohistochemical techniques in sarcoid lymph nodes. Epithelioid cells exhibited intensive expression of ICAM-1, the alpha 5 and the beta 2 molecules. Lymphocytes exhibited intensive expression of ICAM-1, the alpha 4, the alpha 5 and beta 2 molecules. Laminin and type IV collagen were detected at basement membranes in vessels. Fibronectin was distributed within granulomas with a concentric pattern and around granulomas with a fibrillar pattern. Its distribution was well correspondence with the alpha 5 expression. These data suggest that integrin families might play an important role in granuloma formation and migration of lymphocytes into inflamed sarcoid lesions.     

Norepinephrine stimulates mitogen-activated protein kinase activity in GT1-1 gonadotropin-releasing hormone neuronal cell lines

The GT1-1 GnRH neuronal cell lines exhibit highly differentiated properties of GnRH neurons. We have used GT1-1 cells to study the roles of norepinephrine (NE), membrane depolarization, calcium influx, and phorbol esters in the regulation of mitogen-activated protein (MAP) kinase. NE, which is known to stimulate the release of GnRH, induced MAP kinase activity, the tyrosine phosphorylation of MAP kinase, and MAP kinase kinase activity. Forskolin led to activation of MAP kinase comparable with that induced by NE, and a selective inhibitor of cAMP-dependent protein kinase, H8, attenuated the NE-induced activation of MAP kinase. On the other hand, elimination of extracellular calcium by EGTA completely blocked NE-induced tyrosine phosphorylation of MAP kinase, and a selective inhibitor of calcium/calmodulin-dependent protein kinase, KN-62, attenuated the NE-induced activation of MAP kinase. Furthermore, depolarization of GT1-1 cells with 75 mM KCl, 10 microM BayK 8644, or 1 microM calcium ionophore (A23187) induced rapid tyrosine phosphorylation of MAP kinase. The omission of calcium from the extracellular medium completely abolished these effects of tyrosine phosphorylation of MAP kinase. Phorbol 12-myristate 13-acetate (PMA) also induced MAP kinase activity, but pretreatment of the cultured cells with PMA to down-regulate protein kinase C did not abolish the activation of MAP kinase by NE. In addition, although phosphorylation of Raf-1 kinase was stimulated by PMA, this phosphorylation was not induced by either NE or A23187. These results demonstrate that NE activates MAP kinase directly in GT1-1 cells, and that the effect of NE is mediated by increase in the cAMP level and by calcium influx, but not by PMA-sensitive protein kinase C or Raf-1 kinase.     

Thermal conductivity of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions

The thermal conductivities of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions containing CeC up to 10 mol% were determined in the temperature range from 740 to 1600 K by the laser flash method. The thermal conductivity decreased with the cerium content in the solid solutions. The electrical resistivities were also measured for the purpose of analyzing the heat conduction mechanism. It was found that the decrease of electronic heat conduction caused by the addition of cerium resulted in decreasing the thermal conductivities of (U, Ce)C and (U, Pu, Ce)C compared with UC and (U, Pu)C.