Integrated optical chip for a high-resolution, single-resonance-mode x-ray monochromator system.

An integrated optical chip that minimizes the size of the energy-tuning single-resonance-mode x-ray monochromator system into a 3cm×5cm silicon wafer is proposed. A Fabry-Perot x-ray resonator and two back-reflecting Si mirrors are employed on the wafer as the optical components, where Si(12 4 0) back reflection is used for both Fabry-Perot resonance and re-diffraction of the x-ray beams from the resonator in the incident direction. We can achieve an energy bandwidth of 3.4 meV in single-mode x rays and tune the energy by temperature variation. Such Si chips can be readily employed at the synchrotron beamlines and conventional x-ray laboratories for high-resolution investigations.

Interfacial Stability in Bi2Te3 Thermoelectric Joints.

Bismuth telluride (Bi2Te3)-based thermoelectric materials are well-known for their high figure-of-merit (zT value) in the low-temperature region. Stable joints in the module are essential for creating a reliable device for long-term applications. This study used electroless Co-P to prevent a severe interfacial reaction between the joints of solder and Bi2Te3. A thick and brittle SnTe intermetallic compound layer was successfully inhibited. The strength of the joints improved, and the fracture mode became more ductile; furthermore, there was no significant degradation of thermoelectric properties after depositing the Co-P layer after long-term aging. The result suggests that electroless Co-P could enhance the interfacial stability of the joints and be an effective diffusion barrier for Bi2Te3 thermoelectric modules.

Time-resolved X-ray reflection phases of the nearly forbidden Si(222) reflection under laser excitation.

The covalent electron density, which makes Si(222) measurable, is subject to laser excitation. The three-wave Si(222)/(13 {\overline 1}) diffraction at 7.82 keV is used for phase measurements. It is found that laser excitation causes a relative phase change of around 4° in Si(222) in the first 100 ps of excitation and this is gradually recovered over several nanoseconds. This phase change is due to laser excitation of covalent electrons around the silicon atoms in the unit cell and makes the electron density deviate further from the centrosymmetric distribution.

Sapphire hard X-ray Fabry-Perot resonators for synchrotron experiments.

Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.

High-resolution interference-monochromator for hard X-rays.

An X-ray interference-monochromator combining a Fabry-Perot resonator (FPR) and a double-crystal monochromator (DCM) is proposed and realized for obtaining single-mode X-rays with 3.45 meV energy resolution. The monochromator is based on the generation of cavity interference fringes from a FPR and single-mode selection of the transmission spectrum by a DCM of a nearly backward symmetric reflection geometry. The energy of the monochromator can be tuned within 2500 meV(= ΔE) by temperature control of the FPR and the DCM crystals in the range of ΔT = 70 K at room temperature. The diffraction geometry and small size of the optical components used make the interference-monochromator very easy to be adapted in modern synchrotron beamlines and X-ray optics applications.

Single-mode selection for hard x-ray cavity resonance.

Single-mode selection is realized for hard x-ray cavity resonance using a three-mirror crystal device. The developed device consists of two coupled Si Fabry-Perot resonators (FPRs) and uses (12 4 0) backward diffraction to reflect back and forth the incident 14.4388 keV x-ray beam. The coupling between the two cavities gives an effective single-mode spectrum with a bandwidth of 0.81 meV. This method can be used to enhance the longitudinal coherent length without affecting transverse coherence, and is potentially useful in generating nearly total coherent beams in synchrotron or free-electron laser facilities.

Androgen receptor increases CD133 expression and progenitor-like population that associate with cisplatin resistance in endometrial cancer cell line.

Endometrial cancer (EMC) is a sex steroid hormone-related female malignancy. Androgen and androgen receptor (androgen/AR) signals have been implicated in EMC progression. Cancer stem/progenitor cells (CSPCs) are suspected to link to chemoresistance in patients with EMC. In this study, we examined the androgen/AR roles in cisplatin resistance and CSPC population. We found AR expression increased naive EMC side population, CSPC population, cell migration, and epithelial-mesenchymal transition. Meanwhile, it decreased cisplatin cytotoxic effect on EMC cells. Collaterally, endogenous AR expressions in EMC cells were upregulated in the cisplatin-resisting state. Moreover, AR expression could further enhance CD133 expression, CSPC-related markers, and drug-resistance gene messenger RNA expression in EMC cells. Finally, the AR-associated gene expression might go through indirect regulation. This is the first report revealing AR function on EMC cells' CSPC and cisplatin resistance.

Non-genomic estrogen/estrogen receptor α promotes cellular malignancy of immature ovarian teratoma in vitro.

Malignant immature ovarian teratomas (IOTs) most often occur in women of reproductive age. It is unclear, however, what roles estrogenic signaling plays in the development of IOT. In this study, we examined whether estrogen receptors (ERα and ß) promote the cellular malignancy of IOT. Estradiol (E2), PPT (propylpyrazole), and DPN (diarylpropionitrile) (ERα- and ß-specific agonists, respectively), as well as ERα- or ERß-specific short hairpin (sh)RNA were applied to PA-1 cells, a well-characterized IOT cell line. Cellular tumorigenic characteristics, for example, cell migration/invasion, expression of the cancer stem/progenitor cell marker CD133, and evidence for epithelial-mesenchymal transition (EMT) were examined. In PA-1 cells that expressed ERα and ERß, we found that ERα promoted cell migration and invasion. We also found that E2/ERα signaling altered cell behavior through non-classical transactivation function. Our data show non-genomic E2/ERα activations of focal adhesion kinase-Ras homolog gene family member A (FAK-RhoA) and ERK governed cell mobility capacity. Moreover, E2/ERα signaling induces EMT and overexpression of CD133 through upregulation micro-RNA 21 (miR21; IOT stem/progenitor promoter), and ERK phosphorylations. Furthermore, E2/ERα signaling triggers a positive feedback regulatory loop within miR21 and ERK. At last, expression levels of ERα, CD133, and EMT markers in IOT tissue samples were examined by immunohistochemistry. We found that cytosolic ERα was co-expressed with CD133 and mesenchymal cell markers but not epithelial cell markers. In conclusion, estrogenic signals exert malignant transformation capacity of cancer cells, exclusively through non-genomic regulation in female germ cell tumors.

MicroRNA-21 promotes the ovarian teratocarcinoma PA1 cell line by sustaining cancer stem/progenitor populations in vitro.

INTRODUCTION: Resistance of cancer stem/progenitor cells (CSPCs) to chemotherapy can lead to cancer relapse. Ovarian teratocarcinoma (OVTC) arises from germ cells and comprises pluripotent cells that can be used to study cancer cell stemness. In this study, we evaluated whether microRNA-21 (miR-21) promotes ovarian teratocarcinoma by maintaining cancer stem/progenitor populations. METHODS: The lentiviral delivery system was used to upregulate or to suppress the expression of miR-21 in the human ovarian teratocarcinoma cell line PA1 and cell growth assays were used to monitor the expression of miR-21 at different time points. Antibodies directed toward CD133, a stem cell marker, were used to identify CSPCs in the PA1 cell population, and the level of miR-21 expression was determined in enriched CSPCs. Stem cell functional assays (sphere assay and assays for CD133 expression) were used to assess the effects of miR-21 on progression of the CD133+ population. RESULTS: Knockdown of miR-21 in PA1 cells attenuated growth of PA1 cells whereas overexpression of miR-21 promoted cell growth. Moreover, knockdown of miR-21 resulted in a marked reduction in the CD133+ population and sphere formation of CSPCs. In contrast, overexpression of miR-21 resulted in a marked increase in the population of CD133+ cells as well as sphere formation of CSPCs. CONCLUSIONS: MicroRNA-21 plays a significant role in cancer growth by regulating stemness in cancer cells.