Impact of Portlandite on Alkali-Silica Reaction of Pyrex Glass and Blastfurnace Slag Aggregate

In this study, it is investigated the effect of Ca ion on dissolution and reaction products in alkaline environment using Pyrex glass showing ASR expansion and blast furnace slag fine aggregate suppressing ASR. It is reported that Ca plays a role in the dissolution and polymerization of silica, and is therefore an important factor in ASR. For each sample, calculation of dissolution rate and analysis of solid phase product by 29Si MAS NMR and XRD/Rietveld analysis, and liquid phase analysis by ICP-AES were performed. As a result, it was confirmed that addition of Ca has an influence on dissolution behavior of PG and BFS. In the reaction of PG, addition of Ca promotes the polymerization reaction of silica and increases the amount of N-S-H which has expandable and contributes to deterioration mechanism. On the other hand, in BFS, the dissolved silica did not polymerize and N-S-H did not form. It was suggested that the difference in ASR reactivity between PG and BFS is due to the difference in the reaction behavior

Cancer Stem Cells and Aldehyde Dehydrogenase 1 in Liver Cancers

The cancer stem cell (CSC) theory posits that a small population of cells with stem cell-like features is responsible for tumor growth, resistance, and recurrence in many malignancies. This theory could be a useful paradigm for designing innovative targeted drug therapies. Liver cancer is the fifth most common cancer worldwide, with hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) as the predominant forms. Hepatic stem/progenitor cells are believed to be the origin of HCCs and CCAs; however, this remains a controversial topic. Aldehyde dehydrogenase (ALDH) is the main enzymatic system responsible for the clearance of acetaldehyde from the hepatocytes in the liver tissue. Therefore, ALDH1 has been suggested to be a potential, biological and CSC marker in liver cancers. We here provide an overview of the current state of knowledge of CSCs in liver and the role of ALDH1 in the development and progression of liver cancers and discuss its potential value as a prognostic and diagnostic biomarker

Roles of MED1 in Quiescence of Hair Follicle Stem Cells and Maintenance of Normal Hair Cycling

MED1 (mediator complex subunit 1) is expressed by human epidermal keratinocytes and functions as a coactivator of several transcription factors. To elucidate the role of MED1 in keratinocytes, we established keratinocyte-specific Med1-null (Med1epi−/−) mice using the K5Cre/LoxP system. Development of the epidermis and appendages of Med1epi−/− mice were macroscopically and microscopically normal until the second catagen of the hair cycle. However, the hair cycle of Med1epi−/− mice was spontaneously repeated after the second telogen, which does not occur in wild-type (WT) mice. Hair follicles of Med1epi−/− mice could not enter anagen after 6 months of age, resulting in sparse pelage hair in older Med1epi−/− mice. Interfollicular epidermis (IFE) of Med1epi−/− mice was acanthotic and more proliferative than that of WT mice, whereas these findings were less evident in older Med1epi−/− mice. Flow cytometric analysis revealed that the numbers of hair follicle bulge stem cells were reduced in Med1epi−/− mice from a few months after birth. These results suggest that MED1 has roles in maintaining quiescence of keratinocytes and preventing depletion of the follicular stem cells

Identification of New Near-Infrared DIBs in the Orion Nebula

Large organic molecules and carbon clusters are basic building blocks of life, but their existence in the universe has not been confirmed beyond doubt. A number of unidentified absorption features (arising in the diffuse inter-stellar medium), usually called ``Diffuse Inter-stellar Bands (DIBs)'', are hypothesized to be produced by large molecules. Among these, buckminsterfullerene C_60 has gained much attention as a candidate for DIB absorbers because of its high stability in space. Two DIBs at ~9577A and 9632A have been reported as possible features of C_60^+. However, it is still not clear how their existence depends on their environment. We obtained high-resolution spectra of three stars in/around the Orion Nebula, to search for any correlations of the DIB strength with carrier's physical conditions, such as dust-abundance and UV radiation field. We find three DIBs at ~9017A, 9210A, and 9258A as additional C_60^+ feature candidates, which could support this identification. These DIBs have asymmetric profiles similar to the longer wavelength features. However, we also find that the relative strengths of DIBs are close to unity and differ from laboratory measurements, a similar trend as noticed for the 9577/9632 DIBs.Comment: 9 pages, including 3 figures; accepted for publication in the Astrophysical Journa

Accumulation and depuration profiles of PSP toxins in the short-necked clam Tapes japonica fed with the toxic dinoflagellate Alexandrium catenella

A toxic dinoflagellate responsible for paralytic shellfish poisoning (PSP), Alexandrium catenella (Ac) was fed to the short-necked clam Tapes japonica, and the accumulation and depuration profiles of PSP toxins were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested more than 99% of the Ac cells (4_107 cells) supplied once at the beginning of experiment, and accumulated a maximal amount of toxin (185 nmol/10 clams) after 12 h. The rate of toxin accumulation at that time was 23%, which rapidly decreased thereafter. Composition of the PSP toxin accumulated in the clams obviously different from that of Ac even 0.5 h after the cell supply, the proportion of C1+2 being much higher than in Ac, although the reason remains to be elucidated. In contrast, a higher ratio of gonyautoxin (GTX)1+4 than in Ac was detected in the toxin profiles of clam excrements. The variation in toxin composition derived presumably from the transformation of toxin analogues in clams was observed from 0.5 h, such as reversal of the ratio of C1 to C2, and appearance of carbamate (saxitoxin (STX), neoSTX and GTX2, 3) and decarbamoyl (dc) derivatives (dcSTX and dcGTX2, 3), which were undetectable in Ac cells. The total amount of toxin distributed over Ac cells, clams and their excrements gradually declined, and only 1% of supplied toxin was detected at the end of experiment

Self-assembly of Ni-NTA-modified β-Annulus Peptides into Artificial Viral Capsids and Encapsulation of His-tagged Proteins

β-Annulus peptide bearing Cys at the N-terminal from tomato bushy stunt virus was synthesised using a standard Fmoc-protected solid-phase method, and the petide was modified with Ni-NTA at the N-terminal. The Ni-NTA-modified β-annulus peptide self-assembled into virus-like nanocapsules of approximately 40 nm in diameter. The critical aggregation concentration of these nanocapsules in 10 mM Tris-HCl buffer (pH 7.3) at 25°C was 0.053 μM, which is 470 times lower than that of unmodified β-annulus peptides. Moreover, size exclusion chromatography of the peptide assembly indicated encapsulation of His-tagged green fluorescent protein in the Ni-NTA-modified artificial viral capsid

Functional Expression and Characterization of Tetrachloroethene Dehalogenase From Geobacter sp.

Reductive dehalogenase (RDase) consists of two parts, RdhA and RdhB. RdhA is the catalytic subunit, harboring a cobalamin cofactor and two Fe–S clusters. RdhA is anchored to the cytoplasmic membrane via the membrane anchoring subunit, RdhB. There are many genes encoding RDases in the genome of organohalide-respiring bacteria, including Dehalococcoides spp. However, most genes have not been functionally characterized. Biochemical studies on RDases have been hampered by difficulties encountered in their expression and purification. In this study, we have expressed, purified and characterized RdhA of RDase for tetrachloroethene (PceA) from Geobacter sp. PceA was expressed as a fusion protein with a trigger factor tag in Escherichia coli. PceA was purified and denatured in aerobic condition. Subsequently, this protein was refolded in the presence of FeCl3, Na2S and cobalamin in anaerobic condition. The reconstituted PceA exhibited dechlorination ability for tetrachloroethene. UV-Vis spectroscopy has shown that it contains cobalamin and Fe-S clusters. Since this method requires anaerobic manipulation only in the reconstituting process and has a relatively high yield, it will enable further biochemical studies of RDases