Delayed neuronal cell death in brainstem after transient brainstem ischemia in gerbils

Background  

Because of the lack of reproducible brainstem ischemia models in rodents, the temporal profile of ischemic lesions in the brainstem after transient brainstem ischemia has not been evaluated intensively. Previously, we produced a reproducible brainstem ischemia model of Mongolian gerbils. Here, we showed the temporal profile of ischemic lesions after transient brainstem ischemia.     

Two-photon absorption properties of azulenyl compounds having a conjugated ketone backbone

Two-photon absorption (TPA) properties of newly synthesized conjugated ketone derivatives that include nonalternant azulenyl moieties in the pi-conjugation system, alpha,alpha'-bis(1-azulenylidene)cyclopentanone (1Az), alpha,alpha'-bis(2-azulenylidene)cyclopentanone (2Az), and alpha,alpha'-bis(6-azulenylidene)cyclopentanone (6Az) are reported. TPA spectra of these azulenyl compounds were measured using the open-aperture Z-scan method with a femtosecond laser. The TPA cross section at the peak position (sigma(2)peak) of 1Az was found to be the largest among the three azulenyl compounds, which is almost 7 times larger than that of the alpha,alpha'-bis(1-naphthylidene)cyclopentanone (1Nph), an alternant isomer of 1Az with the same number of pi-electrons. The small detuning energies of the azulenyl compounds compared to those of 1Nph were responsible for the large TPA cross sections. We report that a compound having an azulenyl moiety can be a promising TPA material.     

Unusual temperature dependence of enantioselectivity in asymmetric reductions by chiral NADH models

[reaction: see text] Unusual stereoselectivity changes, i.e., enhancement and inversion of enantioselectivity with increasing temperature, were observed in the asymmetric reduction of methyl benzoylformate with chiral 1,4-dihydropyridines possessing amino acid residues as ligating chiral auxiliaries. The differential activation parameters, DeltaDeltaH(S-R) and DeltaDeltaS(S-R), obtained from the Eyring plots demonstrate that the entropy term controls the enantiodifferentiating step, accounting for the observed unique temperature dependencies.     

Effects of blowing or suction on the laminar boundary layer flow over a rotating cone

The effects of suction or blowing at the surface of a rotating cone in a quiet fluid on the skin friction and heat transfer are described. The equations which govern the fluid motion and thermal energy transfer are transformed by the boundary layer approximations and the resulting equations are solved under the condition that the suction or blowing velocity varies as x ⁿ (x: distance measured from the apex of the cone, n: arbitrary constant). The solutions are obtained as a perturbation from the basic laminar flow of an incompressible viscous fluid over the impermeable rotating cone. Detailed numerical calculations are performed for the case of an isothermal rotating cone with uniform blowing or suction, i.e. n=0, the Prandtl number being 0.72. Results are given for the shear stress, heat transfer and velocity and temperature fields. It is shown from the analysis that suction sharply increases the circumferential shear stress and the heat transfer at the surface.Nomenclature c proportional constant - C _fx dimensionless skin friction factor, _x /(V ²) - C _fx0 dimensionless skin friction factor for an impermeable cone - C _fy dimensionless circumferential skin friction factor, _y /(V ²) - C _fy0 dimensionless circumferential skin friction factor for an impermeable cone - c _p specific heat at constant pressure - f _k function of - g _k function of - h heat transfer coefficient, q/(T _w–T ) - k thermal conductivity of fluid - n arbitrary constant - Nu _x local Nusselt number, hx/k - Nu _x0 local Nusselt number for an impermeable cone - Pr Prandtl number - q heat transfer rate - r radius of a circular cross section of the cone, x sin - R _x Reynolds number, Vx/ - T temperature - T _w surface temperature of the cone - T temperature of the surrounding fluid - u fluid velocity in x-direction - v fluid velocity in y-direction - V circumferential velocity at the cone surface, r - w fluid velocity in z-direction - x coordinate along meridional section - y coordinate along a circular cross section - z coordinate perpendicular to both x and y - perturbation parameter, cx ⁿ /(x sin )^1/2 - dimensionless z-coordinate, z( sin /)^1/2 - _k function of - kinematic viscosity - density of fluid - _x skin friction in x-direction - _y circumferential skin friction - stream function - angular speed of the cone     

5-Fluorouracil derivatives ⅩⅩⅢ. Synthesis and antitumor activities of 1-carbamoyl-5-fluorouracils having aromatic ring

In order to get good antitumor agents especially better than 5-fluorouracil,tegafur and l-hexylcarbamoyl-5-fluorouracil (HCFU),fourty nine 1-carbamoyl-5-fluorouracil having aromatic ring were synthesized from 5-fluorouracil and isocyanates or amines.Antitumor activity was tested in the L-1210 tumor system,and 5 compounds gave better value of therapeutic ratio than 5-fluorouracil,tegafur,HCFU.l-(4-Methoxybenzylcarbamoyl)-5-fluorouracil gave the best result.     

N,N-Di-isopropyl-O,O-Di-p-methoxybenzylphosphoramidite——A New Phosphorylating Reagent

Thedibenzyldiisopropylphosphoramidite"',whichcouldbecleavedbyreduction(hydrogenolysis),isaveryusefulreagentforthephosphorylationofhydroxygroupespeciallyvicinalhydroxygroup.Itisusedveryoftenforthesynthesisofnucleotideandmyo-inositolpolyphosphates.However,itcannotbeusedforthephosphorylationofthecompoundshavinganolefinicgroupwhichwouldalsobereducedtoparaffininthereductioncleavingofthebenZylgroup.Now,WereportthesynthesisofanewphosphorylatingreagentN,N-di-isopropyl-O,O-di-P-methox1.Sincep-methox…     

New dimeric and monomeric chromanones,gonytolides D–G,isolated from the fungus Gonytrichum sp.

In the course of the screening of innate immune regulators from natural resources, we isolated new dimeric and monomeric chromanones, gonytolides D–G (4–7), from Gonytrichum sp. along with a known innate immune promoter, gonytolide A (1). The structures of these compounds were determined by spectral analysis, chemical conversion, and biogenetic consideration. The compounds 4–7 were evaluated on the innate immune response, indicating that the 8,8′-linked bischromanone rings were crucial for innate immune-promoting activity.