Hexagonally deformed Fermi surface of the 3D topological insulator Bi2Se3

A hexagonal deformation of the Fermi surface of Bi2Se3 has been for the first time observed by angle-resolved photoemission spectroscopy. This is in contrast to the general belief that Bi2Se3 possesses an ideal Dirac cone. The hexagonal shape is found to disappear near the Dirac node, which would protect the surface state electrons from backscattering. It is also demonstrated that the Fermi energy of naturally electron-doped Bi2Se3 can be tuned by 1% Mg doping in order to realize the quantum topological transport.

Characterization of oxide scales thermally formed on single-crystal silicon carbide

Microstructures of oxide scales thermally formed on single-crystal silicon carbide were investigated using transmission electron microscopy. The oxide scales were formed on the Si-face of 6H-SiC at 1273-1473 K in dry oxygen. Spherical patterns were observed on the surfaces of the oxidized samples by an optical microscope in some regions. In these regions, cross-sectional transmission electron microscopy (TEM) observations show that the oxide scale was divided into two layers; the upper layer (surface side) was composed of crystalline silica, and the lower layer on the silicon carbide substrate was amorphous silica, while the oxide scales in the surroundings of the patterns were composed of only amorphous silica. The oxidation activation energy in the amorphous silica layer of the Si-face of 6H-SiC was found to be 408 kJ/mol by the evolution of thickness directly measured from the cross-sectional scanning electron microscopy and TEM images.

STAT3 inhibitor WP1066 as a novel therapeutic agent for renal cell carcinoma

Background:

Signal transducer and activator of transcription 3 (STAT3) regulates the expression of genes that mediate cell survival, proliferation, and angiogenesis and is aberrantly activated in various types of malignancies, including renal cell carcinoma (RCC). We examined whether it could be a novel therapeutic target for RCC by using the STAT3 inhibitor WP1066.

Methods:

The antitumour activities and related mechanisms of WP1066 were investigated in vitro on renal cancer cell lines and in vivo on murine xenografts.

Results:

In Caki-1 and 786-O renal cancer cells, 5 μM WP1066 prevented the phosphorylation of STAT3, and 2.5 μM WP1066 significantly (P<0.01) inhibited cell survival and proliferation. WP1066 suppressed the expression of Bcl-2, induced apoptosis, and inhibited the basal and hypoxia-induced expression of HIF1α and HIF2α, as well as vascular endothelial growth factor secretion into cell culture medium. Human umbilical vascular endothelial cells cocultured with media from WP1066-treated cells showed significantly reduced tubulogenesis (P<0.05). Systemic oral administration of WP1066 to mice for 19 days significantly inhibited the growth of Caki-1 xenograft tumours (P<0.05), and pathological analysis of xenografts of WP1066-treated mice showed decreased immunostaining of phosphorylated STAT3 and reduced length of CD34-positive vessels (P<0.05).

Conclusion:

Our results suggest that using WP1066 to inhibit the STAT3 signalling pathway could be a novel therapeutic strategy against RCC.

Multiplexing capability in polychromatic reconstruction with selective detection method

Holographic reconstruction with polychromatic light was investigated in terms of the multiplexing capability in a volume holographic memory. The broadband spectrum of the probe beam considerably degrades the angular selectivity and causes a serious deterioration of the multiplexing capability, but this can be overcome if an additional suitable optical component is used in the imaging system. We could selectively detect the signal image alone even though the angular separation between holograms was insufficient to suppress the diffraction from other holograms. We theoretically derived the minimum angular separation for multiplexing and experimentally demonstrated the effectiveness of this selective detection method.

In situ transmission electron microscopy observation of the growth of bismuth oxide whiskers

Growth of bismuth oxide (most probably Bi2O3) was observed in situ in a transmission electron microscope. Bi liquid particles were dispersed on the substrates of diamond or SiO2. Introduction of oxygen up to 5 x 10-4 Pa resulted in formation of bismuth oxide (most probably Bi2O3) whiskers. The growth mechanism of the whisker was discussed in terms of a vapor-liquid-solid (VLS) mechanism. It is suggested that the liquid droplet of Bi acts as a physical catalyst for growth of bismuth oxide (most probably Bi2O3) whiskers.

Importance of co-cultivation medium pH for successful Agrobacterium-mediated transformation of Lilium x formolongi

An efficient system for Agrobacterium-mediated transformation of Lilium x formolongi was established by preventing the drastic drop of pH in the co-cultivation medium with MES. Meristematic nodular calli were inoculated with an overnight culture of A. tumefaciens strain EHA101 containing the plasmid pIG121-Hm which harbored intron-containing beta-glucuronidase (GUS), hygromycin phosphotransferase (HPT), and neomycin phosphotransfease II (NPTII) genes. After three days of co-cultivation on 2 g/l gellan gum-solidified MS medium containing 100 microM acetosyringone, 30 g/l sucrose, 1 mg/l picloram and different concentrations of MES, they were cultured on the same medium containing 12.5 mg/l meropenem to eliminate Agrobacterium for 2 weeks and then transferred onto medium containing the same concentration of meropenem and 25 mg/l hygromycin for selecting putative transgenic calli. Transient GUS expression was only observed by adding MES to co-cultivation medium. Hygromycin-resistant transgenic calli were obtained only when MES was added to the co-cultivation medium especially at 10 mM. The hygromycin-resistant calli were successfully regenerated into plantlets after transferring onto picloram-free medium. Transformation of plants was confirmed by histochemical GUS assay, PCR analysis and Southern blot analysis.

[Evaluation of gambir quality based on quantitative analysis of polyphenolic constituents]

Gambir (asen'yaku in Japanese), an aqueous extract of leaves and young twigs of Uncaria gambir Roxb., has traditionally been used as a treatment for diarrhea and dysentery as an internal medicine and for sore throat as a gargle. Although it is a pharmacopoeic medicine in Japan, the quantitative evaluation of its constituents has not yet been adopted in the Japanese pharmacopoeia. We analyzed polyphenolic constituents in 31 gambir and related products to establish evaluation methods, since gambir contains large amounts of polyphenolic constituents. The total flavan contents in the samples revealed using the vanillin-HCl estimation method ranged from 24-79%. Reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that catechin was the most abundant constituent in each sample, with contents in the range of 7-76%. The catechin contents in the gambir products between the first and third quartiles were 28-54%. Thus, the lower limit of the catechin content in gambir products can be set at around 20% for quality management. Fifteen tested samples were subjected to HPLC analysis to show the presence of epicatechin (1.5% on average) and the dimeric compounds procyanidin B1, procyanidin B3, and gambiriin A1 (ca. 1% each). The molecular weight distributions of polymeric flavans in the gambir products were analyzed by gel permeation chromatography (GPC) and showed that the average degree of polymerization for each sample was 3 to 7. These results indicate that the combination of the vanillin-HCl method, RP-HPLC analysis, and GPC analysis gives valuable information for evaluating the polyphenolic profiles of gambir products.

303 FERTILIZATION-RELATED PARAMETERS OF FROZEN - THAWED SPERMATOZOA FROM SUBFERTILE JAPANESE BLACK CATTLE

The subfertility derived from male factors is a problem of concern in domestic animals, because it could cause a disintegration of the breeding system and large economic losses, particularly when the subfertility affects genetically superior male animals. Therefore, it is urgent that causal factors of male subfertility be determined. Recently, an increasing number of subfertile bulls have been found among Japanese Black cattle, which is a representative breed of Japanese beef cattle. The purpose of the present study was to elucidate causal factors of male subfertility in Japanese Black cattle. Frozen–thawed spermatozoa from 8 subfertile (S1-S8) and 7 fertile (F1–F7, control) bulls were used for the assessment of fertilization-related parameters. The data obtained from each subfertile bull in the following experiments were individually compared with the mean values of the fertile bull group. In Experiment 1, sperm motility was observed in samples that were frozen-thawed and subsequently washed in PBS. Many spermatozoa (higher than 65%) exhibited flagellar movement in all samples from fertile and subfertile bulls. However, the percentages of progressively motile spermatozoa from 2 subfertile bulls were significantly lower (S2: 6%; S7: 7%; P &lt; 0.05, ANOVA and Tukey&apos;s multiple range tests) than those from fertile bulls (average: 37&percnt;). Moreover, rapidly progressive movement was not observed in the spermatozoa from 4 subfertile bulls (S1, S2, S6, and S7). These data suggest abnormality in the motility system of sperm flagella in these 4 subfertile bulls. In Experiment 2, the capacitation&ndash;acrosome reaction state of frozen&ndash;thawed spermatozoa was examined by the CTC-staining assay. More than 50&percnt; of the frozen&ndash;thawed spermatozoa from 4 subfertile bulls (S5&ndash;S8) were prematurely progressing in the capacitation state immediately after washing and resuspension in the medium lacking CaCl2. Moreover, the addition of CaCl2 to the medium induced acrosomal loss in these sperm samples (percentages of spermatozoa without the acrosome: 36&ndash;49&percnt;). These findings indicate the occurrence of premature capacitation and a spontaneous acrosome reaction in spermatozoa from these 4 subfertile bulls. In Experiment 3, the in vitro fertilizing ability of frozen&ndash;thawed spermatozoa was evaluated by the IVF test. The percentages of fertilized eggs with both male and female pronuclei or developmental rates of fertilized eggs to the 2-cell or 4-cell stage were significantly lower in the spermatozoa from S6 to S8 bulls than in those from fertile bulls (P &lt; 0.05, chi-squared tests). This may suggest that spermatozoa from these 3 subfertile bulls hardly accomplish the normal fertilization process. In summary, low progressive motility and low in vitro fertilizing ability because of premature capacitation were found in the spermatozoa from subfertile bulls. It is therefore possible that these are causal factors for the subfertility of male Japanese Black cattle.

Revised Structures of Gambiriins A1, A2, B1, and B2, Chalcane-Flavan Dimers from Gambir (Uncaria gambir Extract)

Gambir, the aqueous extract from Uncaria gambir (Rubiaceae), has been used as an astringent medicine in Asian countries. Investigation of the constituents in the extract led to the isolation of four chalcane-flavan dimers, gambiriin A1 (6), A2 (7), B1 (8), and B2 (9), in addition to (+)-catechin (1), (+)-epicatechin (2), and dimeric proanthocyanidins, procyanidin B1 (3), procyanidin B3 (4), and gambiriin C (5). The spectroscopic and chemical data obtained in the present study indicated that their previously proposed structures 6a, 7a, 8a, and 9a should be revised to 6, 7, 8, and 9, respectively.

Stem cell based therapies to treat muscular dystrophy

Muscular dystrophies comprise a heterogeneous group of neuromuscular disorders, characterized by progressive muscle wasting, for which no satisfactory treatment exists. Multiple stem cell populations, both of adult or embryonic origin, display myogenic potential and have been assayed for their ability to correct the dystrophic phenotype. To date, many of these described methods have failed, underlying the need to identify the mechanisms controlling myogenic potential, homing of donor populations to the musculature, and avoidance of the immune response. Recent results focus on the fresh isolation of satellite cells and the use of multiple growth factors to promote mesangioblast migration, both of which promote muscle regeneration. Throughout this chapter, various stem cell based therapies will be introduced and evaluated based on their potential to treat muscular dystrophy in an effective and efficient manner.