A comparative study of transcranial Doppler sonography and near-infrared spectroscopy for the assessment of cerebrovascular CO2 reactivity

Oleanolic acid (1) was identified as an anti-HIV principle from several plants, including Rosa woodsii (leaves), Prosopis glandulosa (leaves and twigs), Phoradendron juniperinum (whole plant), Syzygium claviflorum (leaves), Hyptis capitata (whole plant), and Ternstromia gymnanthera (aerial part). It inhibited HIV-1 replication in acutely infected H9 cells with an EC50 value of 1.7 microg/mL, and inhibited H9 cell growth with an IC50 value of 21.8 microg/mL [therapeutic index (T. I.) 12.8]. Pomolic acid, isolated from R. woodsii and H. capitata, was also identified as an anti-HIV agent (EC50 1.4 microg/mL, T. I. 16.6). Although ursolic acid did show anti-HIV activity (EC50 2.0 microg/mL), it was slightly toxic (IC50 6.5 microg/mL, T. I. 3.3). A new triterpene (11) was also isolated from the CHCl3-soluble fraction of R. woodsii, though it showed no anti-HIV activity. The structure of 11 was determined to be 1beta-hydroxy-2-oxopomolic acid by spectral examination. Based on these results, we examined the anti-HIV activity of oleanolic acid- or pomolic acid-related triterpenes isolated from several plants. In addition, we previously demonstrated that derivatives of betulinic acid, isolated from the leaves of S. claviflorum as an anti-HIV principle, exhibited extremely potent anti-HIV activity. Accordingly, we prepared derivatives of oleanolic acid and evaluated their anti-HIV activity. Among the oleanolic acid derivatives, 18 demonstrated most potent anti-HIV activity, with an EC50 value of 0. 0005 microg/mL and a T. I. value of 22 400.     

Capillary gas-liquid chromatographic separation of oxo and oxo-hydroxy bile acid isomers of theallo and normal series

Capillary gas-liquid chromatographic separation was studied for 60 oxo and oxo-hydroxy bile acids of theallo (5α-H, A/B-trans) and normal (5β-H, A/B-cis) series, which differ from one another in the number, position, and configuration of oxo and hydroxy groups at positions C−3, C−4, C−6, C−7, and/or C−12. Good separation of the isomers was achieved by the use of an aluminum-clad fused-silica capillary column coated with bonded and cross-linked methyl polysiloxane.     

Characteristics of a Nonstoichiometric Gd3+δ(Al,Ga)5−δO12:Ce Garnet Scintillator

We have developed a new nonstoichiometric Gd_3+δ(Al,Ga)_5−δO₁₂:Ce garnet scintillator for an X-ray CT scanner. For commercially used scintillators, reproducible luminescence properties are of great importance. We have found that the afterglow properties of the garnet change drastically in the vicinity of the stoichiometric compositions. The most suitable properties are obtained at slightly excess (Gd,Ce) compositions from the stoichiometry. In order to investigate the afterglow properties, crystallography arrangements, phase equilibrium relationship between crystal phases, and luminescence characteristics of host material doped with different valence ions have been examined. The luminescence properties are explained by isoelectronic traps based on the difference in the electronegativity of the dopant and host ions, which would act as electron trap centers and hole trap centers within the band gap.     

Microstructure of Sm5Ni19 intermetallic compound observed by high-resolution electron microscope

The method of high-resolution electron microscopy is applied to study the microstructure of the Sm–Ni intermetallic compound whose composition is near the Sm₅Ni₁₉. Several new polytypic structures (5T, 7T, 15R and 18R) are found and their crystal structures are analysed by high-resolution imaging method combined with electron diffraction method. Various kinds of defects are observed and the atomic arrangements near the defects are deduced; the defects include stacking faults in Sm₅Ni₁₉, intergrowth of the Sm₂Ni₇ or other complex structures in between the matrix of Sm₅Ni₁₉, complicated defect structure which changes the stacking sequence of Sm₅Ni₁₉, and lattice defects in the region of terminating the intergrowth.     

Thickness-shear stress distributions of the oscillating planoconvex AT-cut quartz-crystal resonator

Thickness-shear stress distributions of a planoconvex AT-cut quartz-crystal resonator oscillating with the fundamental, 3rd overtone and 5th overtone thickness-shear vibration resonant frequencies are measured by means of a laser-beam modulation method. The measured stress distributions are compared with the stress values computed by the finite element method for a simulation study. The experimental values show good agreement with the computed stress distributions. The absolute value of the measured stress agrees with that in the experiment of Spencer.     

Sludge depositions in a long tube-high flow MSF test plant

During the operation of a multistage flash (MSF) evaporation plant, a rather rapid decrease was observed in the economy ratio of the plant when the dissolved oxygen (DO) content of the circulating brine was at a high level. This phenomenon was brought about by the reduction of heat transfer coefficients of condenser tubes due to sludge formation on the inside tube surface by the co-precipitation of ferric hydrous oxide with silica, alumina, and organic materials. The chemical analysis of the sludge and circulating brine showed a close relationship to DO values in the brine, the concentration of iron in the sludge, and the decreasing value of the heat transfer coefficient. The lowering of DO was found very effective for avoiding the sludge trouble.     

Fundamental characteristics of a synthesized light source for optical coherence tomography

We describe the fundamental characteristics of a synthesized light source (SLS) consisting of two low-coherence light sources to enhance the spatial resolution for optical coherence tomography (OCT). The axial resolution of OCT is given by half the coherence length of the light source. We fabricated a SLS with a coherence length of 2.3 microm and a side-lobe intensity of 45% with an intensity ratio of LED1:LED2 = 1:0.5 by combining two light sources, LED1, with a central wavelength of 691 nm and a spectral bandwidth of 99 nm, and LED2, with a central wavelength of 882 nm and a spectral bandwidth of 76 nm. The coherence length of 2.3 microm was 56% of the shorter coherence length in the two LEDs, which indicates that the axial resolution is 1.2 microm. The lateral resolution was measured at less than 4.4 microm by use of the phase-shift method and with a test pattern as a sample. The measured rough surfaces of a coin are illustrated and discussed.     

Interaction of tocored with unsaturated fatty esters

Tocored, an oxidation product of tocopherol and its model, 2,2,7,8-tetramethyl-5,6-chromanquinone reacted with methyl linoleate at an elevated temperature to form an adduct with isomerized linoleate. Oxidation of tocored in fatty esters produced a variety of products, depending on the degree of unsaturation of the esters. With methyl palmitate no addition product was detected but tocopurple and tocoreddimer were identified as minor products irrespective of the degree of saturation. A mechanism involving the interaction of tocored with lipid radicals to yield an adduct as the consequence of antioxidative action of tocored is postulated.