On the intensities ofK X rays following thermal neutron capture

Through the measurement of the absolute intensities of theK _α andK _β X rays following slow neutron capture in¹⁵⁵Gd,¹⁷⁶Lu and¹⁹⁹Hg and their comparison with the intensities of theK-conversion electron transitions from the same reaction it is shown that theK X rays are caused only by internal conversion.     

Isolation from pig liver microsomes, identification by tandem mass spectrometry and in vitro immunosuppressive activity of an SDZ-RAD 17,18,19,20,21,22-tris-epoxide

Macrolide immunosuppressive drugs such as tacrolimus (FK506) and sirolimus (rapamycin) are compounds largely used in modern immunosuppressive therapy and considered as powerful immunosuppressive agents. Some of these molecules are still under clinical development as, for example, SDZ-RAD (40-O-(2-hydroxyethyl)rapamycin), an immunosuppressive drug closely related to rapamycin. SDZ-RAD has a molecular mass of 957.57 Da (C53H83NO14) and shares the same common intracellular receptor as tacrolimus, the FK-506 binding protein (FKBP-12). SDZ-RAD exerts its pharmacological effect by binding to a different effector protein, inhibits the S6p 70-kinase and interrupts a different signal transduction pathway than tacrolimus. Both SDZ-RAD and rapamycin are metabolized mainly by the cytochrome P-450 3A4-dependent mixed function oxygenase enzyme system to hydroxylated and demethylated metabolites. We describe here the isolation from pig liver microsomes of a novel SDZ-RAD metabolite identified by electrospray tandam mass spectrometry as a new SDZ-RAD 17,18,19,20,21,22-tris-epoxide metabolite. The in vitro immunosuppressive activity as measured by the mixed lymphocyte reaction is more or less comparable to that of SDZ-RAD, although its pharmacological mode of action may be different from that classically described for rapamycin.     

Experimental and theoretical investigation of fmr in (111) thin garnet films with applied uniaxial stress

Analytical expressions for the resonance field shiftδH caused by an applied stressσ are deduced forH _e ∥ [¯1¯12] in the film plane, taking into account also the quadratic terms (～σ²) besides the dominant linear terms (～σ). The linear part ofδH=f(σ) forH _e andσ lying in the film plane depends only on the relative angle betweenH _e andσ, so that for the measurement of magnetostriction constants it is not necessary to have crystallographically oriented thin films.δH forH _e perpendicular to the film is very sensitive to deviations from the perpendicular direction. Both magnetostriction constants λ₁₁₁ and λ₁₀₀ were evaluated on (111) thin YIG ∶ Mn film.     

Fabrication of silicon webs in the decananometre range

In addition to the high demands on lithography, short-channel effects are problems for miniaturisation of devices. Double-gate MOSFETs are known to improve the short-channel behaviour and are traded in the ITRS roadmap as a part of non-classical CMOS, which can provide a path to scaling MOSFETs below the 65-nm node. For the centre of a special vertical layout a silicon web with 300-nm height and 20-nm width is required. The web lines are made by electron-beam lithography with hydrogen silsesquioxane (HSQ) as negative tone resist. 23-nm wide and 100-nm high lines in HSQ were attained. The transfer of the structures to a substrate by dry etching results in 30-nm-wide and 300-nm-high silicon lines. PACS 81.16.Nd; 81.16.Rf; 85.30.Tv     

Aspects of quadratic gravity

We discuss quadratic gravity where terms quadratic in the curvature tensor are included in the action. After reviewing the corresponding field equations, we analyze in detail the physical propagating modes in some specific backgrounds. First we confirm that the pure R² theory is indeed ghost free. Then we point out that for flat backgrounds the pure R² theory propagates only a scalar massless mode and no spin‐two tensor mode. However, the latter emerges either by expanding the theory around curved backgrounds like de Sitter or anti‐de Sitter, or by changing the long‐distance dynamics by introducing the standard Einstein term. In both cases, the theory is modified in the infrared and a propagating graviton is recovered. Hence we recognize a subtle interplay between the UV and IR properties of higher order gravity. We also calculate the corresponding Newton's law for general quadratic curvature theories. Finally, we discuss how quadratic actions may be obtained from a fundamental theory like string‐ or M‐theory. We demonstrate that string theory on non‐compact manifolds, like a line bundle over , may indeed lead to gravity dynamics determined by a higher curvature action.     

Cytotoxic and Anti-Inflammatory Activities of Dihydroisocoumarin and Xanthone Derivatives from Garcinia picrorhiza

Garcinia picrorhiza, a woody plant native to Sulawesi and Maluku Islands, Indonesia, has been traditionally used as a wound healing ointment. In our continuous search for bioactive compounds from this plant, 15 phenolic compounds were isolated from its stem bark, including a previously undescribed dihydroisocoumarin, 2′-hydroxyannulatomarin, and two undescribed furanoxanthones, gerontoxanthone C hydrate and 3′-hydroxycalothorexanthone. The structures of the new metabolites were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR and HRESIMS. Gerontoxanthone C hydrate possessed cytotoxicity against four cancer cells (KB, HeLa S3, MCF-7, and Hep G2) with IC₅₀ values ranging from 5.6 to 7.5 µM. Investigation on the anti-inflammatory activities showed that 3′-hydroxycalothorexanthone inhibited NO production in RAW 264.7 and BV-2 cell lines with IC₅₀ values of 16.4 and 13.8 µM, respectively, whereas only (−)-annulatomarin possessed inhibition activity on COX-2 enzyme over 10% at 20 µM. This work describes the presence of 3,4-dihydroisocoumarin structures with a phenyl ring substituent at C-3, which are reported the first time in genus Garcinia. These findings also suggest the potential of furanxanthone derivatives as cytotoxic and anti-inflammatory agents for further pharmacological studies.     

The competition between crystallization and demixing in polymer blends. V. Numerical modeling and quantitative evaluation of crystallization-induced composition inhomogeneities

It is well known that crystallization of one component in a polymer blend causes composition profiles around the growing spherulites. Amplitude and width of these profiles, respectively, depend on the ratio between the rates of diffusion and of spherulite growth. They can be determined by suitable experimental means. In the present article, the profiles are modeled, starting from Frank's solution of the diffusion equation in spherical coordinates under the boundary condition of moving walls that simultaneously are sources of the diffusing material. Modeled and experimentally determined profiles in PVDF/PEA and PCL/PS blends agree well. The analysis yields estimates for the diffusion coefficient D in polymeric melts as D ≅ (50 ··· 500) μm²/h. Finally, the interference of the composition profiles around several adjacent spherulites can be demonstrated. © 1996 John Wiley & Sons, Inc.     

Stochastic Analysis of the Fractional Brownian Motion

Since the fractional Brownian motion is not a semi-martingale, the usual Ito calculus cannot be used to define a full stochastic calculus. However, in this work, we obtain the Itô formula, the Itô–Clark representation formula and the Girsanov theorem for the functionals of a fractional Brownian motion using the stochastic calculus of variations.