Four new ursane-type triterpenes, olibanumols K, L, M, and N, from traditional egyptian medicine olibanum, the gum-resin of Boswellia carterii

Four new ursane-type triterpenes, olibanumols K (1), L (2), M (3), and N (4), were isolated from traditional Egyptian medicine olibanum, the exuded gum-resin from Boswellia carterii BIRDW. Their structures were elucidated on the basis of chemical and physicochemical evidence.     

Structures of novel norstilbene dimer, longusone A, and three new stilbene dimers, longusols A, B, and C, with antiallergic and radical scavenging activities from Egyptian natural medicine Cyperus longus

The methanolic extract of the whole plant of Cyperus longus originating in Egypt was found to show antiallergic effect on ear passive cutaneous anaphylaxis reactions in mice. By bioassay-guided separation, 11 stilbenes and stilbene dimers including a novel norstilbene dimer, longusone A, and three new stilbene dimers, longusols A, B, and C, were isolated. Their structures were elucidated on the basis of chemical and physicochemical evidence. Among the isolates, longusol B (IC(50)=96 μM), luteolin (3.0 μM), resveratrol (17 μM), piceatannol (24 μM), and cassigarols E (84 μM) and G (84 μM) were found to inhibit the release of β-hexosaminidase, as a marker of antigen-induced degranulations, in rat basophilic leukemia (RBL-2H3) cells. In addition, the methanolic extract and the constituents showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (SC(50)=22 μg/ml and 2.8-29 μM, respectively).     

Medicinal Flowers. XXXI. Acylated oleanane-type triterpene saponins, Sasanquasaponins I-V, with antiallergic activity from the flower buds of Camellia sasanqua

The methanolic extract and its 1-butanol-soluble fraction from the flower buds of Camellia sasanqua THUNB. were found to show inhibitory activities on the release of β-hexosaminidase from rat basophile leukemia (RBL-2H3) cells. From the 1-butanol-soluble fraction, five new acylated oleanane-type triterpene saponins, sasanquasaponins I-V, were isolated together with a known saponin and their chemical structures were elucidated on the basis of chemical and physicochemical evidence. The principal saponin constituents, sasanquasaponins I-III, with an acyl group at the 22-position of the aglycon part showed the inhibitory effects on the release of β-hexosaminidase and some structure-activity relationships were reported.     

InN thin film lattice dynamics by grazing incidence inelastic x-ray scattering

Achieving comprehensive information on thin film lattice dynamics so far has eluded well established spectroscopic techniques. We demonstrate here the novel application of grazing incidence inelastic x-ray scattering combined with ab initio calculations to determine the complete elastic stiffness tensor, the acoustic and low-energy optic phonon dispersion relations of thin wurtzite indium nitride films. Indium nitride is an especially relevant example, due to the technological interest for optoelectronic and solar cell applications in combination with other group III nitrides.     

Ideal shear strength under compression and tension in C, Si, Ge, and cubic SiC: an ab initio density functional theory study

Ideal shear strength under superimposed normal stress of cubic covalent crystals (C, Si, Ge, and SiC) is evaluated by ab initio density functional theory calculation. Shear directions in [112] and [110] on the (111) plane are examined. The critical shear stress along the former direction is lower than that along the latter in all the crystals unless the hydrostatic tension is extremely high. In both the [112]-shear and [110]-shear, critical shear stress is increased by compression in C but is decreased in the other crystals. The different response of the critical shear stress to normal stress is due to the strength of the bond-order term, i.e., dependence of the short-range interatomic attraction on the bond-angle.     

Evolution of the Kondo effect in a quantum dot probed by shot noise

We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the noninteracting model, reaching 1.8±0.2.     

A case of Budd-Chiari syndrome: Gd-EOB-DTPA-enhanced MR findings

Budd-Chiari syndrome (BCS) is a rare disorder caused by the obstruction of hepatic venous outflow, leading to sinusoidal congestion, ischemic injury to liver cells and portal hypertension. Long-term survival largely depends on whether hepatocellular carcinoma occurs. A recently available liver-specific contrast medium, gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA), reportedly has high diagnostic capability for detection of malignant liver tumors. However, there has been no report of the sue of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for BCS. We present a case of chronic BCS who underwent both gadopentetate dimeglumine (Gd-DTPA) and Gd-EOB-DTPA-enhanced MRI. Hepatic congestion and edema were seen as slightly hypointense areas on Gd-EOB-DTPA-enhanced hepatobiliary-phase images, although these areas were observed as slightly hyperintense on previously obtained Gd-DTPA-enhanced delayed-phase image. Reduced uptake of Gd-EOB-DTPA by hepatocytes in the region of congestion or edema may account for this difference, which should be recognized in image interpretations.     

Crystal growth and luminescent properties of Pr-doped K(Y,Lu)3F10 single crystal for scintillator application

Pr1%:K(Y_1−xLu_x)₃F₁₀ (x=0, 0.2, 0.4) single crystals were grown by the μ-PD method. All the grown crystals were greenish and perfectly transparent without any inclusions or cracks. Radioluminescence spectra and decay kinetics of the Pr1%:K(Y,Lu)₃F₁₀ crystals were measured. Emission from the Pr³⁺ 5d–4f transition, peaking around 260 nm and of the decay time of around 22 ns were observed. The 5d–4f emission intensities of the Pr1%:K(Y,Lu)₃F₁₀ crystals were higher than that of the standard BGO scintillator.     

A study on the role of gelatin in methacrylic-acid-based gel dosimeters

In radiotherapy treatment, polymer gel dosimetry can be used for verifying three-dimensional (3D) dose distributions. Gelatin is generally used as a gelling agent in the dosimeters. In this paper, another role of gelatin in a methacrylic-acid-based gel dosimeter (MAGAT) is investigated. Temperature increases due to exothermic polymerization in the irradiated gel are measured directly. Dose–R₂ responses are also obtained using MRI. It is shown that no appreciable increases in either temperature or R₂ are observed in MAGAT dosimeters made without gelatin, and that significant temperature and R₂ increases are observed when very low gelatin concentrations are used. These results indicate that gelatin is an important enabler for radiation-induced free-radical polymerization in methacrylic-acid-based gels. When gelatin is replaced by amino acids, changes in temperature are observed, along with small changes in R₂. The resulting dosimeter solutions remain transparent because the polymer does not precipitate as it does in regular MAGAT dosimeters containing gelatin. When the amino acids are replaced by acids without amino groups, no temperature or R₂ changes are observed, indicating that no polymer forms. These results show that amino groups (and possibly other functional groups) on the gelatin catalyze the radiation-induced free-radical polymerization that occurs in MAGAT dosimeters.