Gas6 Downregulation Impaired Cytoplasmic Maturation and Pronuclear Formation Independent to the MPF Activity

Previously, we found that the growth arrest-specific gene 6 (Gas6) is more highly expressed in germinal vesicle (GV) oocytes than in metaphase II (MII) oocytes using annealing control primer (ACP)-PCR technology. The current study was undertaken to investigate the role of Gas6 in oocyte maturation and fertilization using RNA interference (RNAi). Interestingly, despite the specific and marked decrease in Gas6 mRNA and protein expression in GVs after Gas6 RNAi, nuclear maturation including spindle structures and chromosome segregation was not affected. The only discernible effect induced by Gas6 RNAi was a change in maturation promoting factor (MPF) activity. After parthenogenetic activation, Gas6 RNAi-treated oocytes at the MII stage had not developed further and arrested at MII (90.0%). After stimulation with Sr2+, Gas6-silenced MII oocytes had markedly reduced Ca2+ oscillation and exhibited no exocytosis of cortical granules. In these oocytes, sperm penetration occurred during fertilization but not pronucleus (PN) formation. By roscovitine and colcemid treatment, we found that the Gas6 knockdown affected cytoplasmic maturation directly, independent to the changed MPF activity. These results strongly suggest that 1) the Gas6 signaling itself is important to the cytoplasmic maturation, but not nuclear maturation, and 2) the decreased Gas6 expression and decreased MPF activity separately or mutually influence sperm head decondensation and PN formation

Circulating tumor cells detected by lab-on-adisc: Role in early diagnosis of gastric cancer

[Background] The use of circulating tumor cells (CTCs) as an early diagnostic biomarker and prognostic indicator after surgery or chemotherapy has been suggested for various cancers. This study aimed to evaluate CTCs in patients who underwent gastrectomy for gastric cancer and to explore their clinical usefulness in the early diagnosis of gastric cancer. [Methods] A total of 116 patients with gastric cancer who underwent gastrectomy and 31 healthy volunteers were prospectively included between 2014 and 2015. Peripheral blood samples were collected before gastrectomy, and CTCs were examined using a centrifugal microfluidic system with a new fluid-assisted separation technique. [Results] After creating a receiver operating characteristic curve to identify the discriminative CTC value needed differentiate patients with gastric cancer from healthy volunteers, sensitivity and specificity were nearly optimized at a CTC threshold of 2 per 7.5 mL of blood. Of the 102 persons with a CTC level >= 2 per 7.5 mL of blood, 99 (97.1%) had gastric cancer, and of the 45 persons with a CTC level <2 per 7.5 mL of blood, 28 (62.2%) were healthy controls. Accordingly, the sensitivity and specificity for the differentiation of patients with gastric cancer from healthy controls were 85.3% and 90.3%, respectively. However, the presence of CTCs was not associated with any clinicopathologic features such as staging, histologic type, or mucin phenotype. [Conclusion] Although we could not prove the clinical feasibility of CTCs for gastric cancer staging, our results suggest a potential role of CTCs as an early diagnostic biomarker of gastric cancer

A study on geometry effect of transmission coil for micro size magnetic induction coil

The effects of transmission (Tx) coil structure have been studied for micro-size magnetic induction coil. The size of the receiving (Rx) coil should be shrunk to the micrometer level for the various new applications such as micro-robot and wireless body implanted devices. In case of the macro-scale magnetic induction coil, the power transmission efficiency is generally considered to be higher as the inductance of the transmission coil became larger; however, the large size difference between macro-size Tx coil and micro-size Rx coil can decrease the power transmission efficiency due to the difference of resonance frequency. Here, we study a correlation of the power transmission with the size and distance between the macro-size Tx and micro-size Rx coils using magnetic induction technique. The maximum power efficiency was 0.28/0.23/0.13/0.12% at the distance of 0.3/1/3/5 cm between Rx and Tx coil. In addition, more efficient wireless power transferring method is suggested with a floating coil for the body implantable devices. The voltage output increased up to 5.4 mV than the original one Tx coil system. The results demonstrated the foundational wireless power transferring system with enhanced power efficiency. © 2016 Elsevier Ltd. All rights reserved.

Sintering behavior and electrochemical performances of nano-sized gadolinium-doped ceria via ammonium carbonate assisted co-precipitation for solid oxide fuel cells

Ultra-fine Gd-doped ceria (GDC) powders were synthesized via co-precipitation using ammonium carbonate as the precipitant. The crystallite size of the resultant GDC powders was measured as ∼33 nm. The dilatometry test of the powder compacts and the relative density measurement of sintered pellets with various sintering temperatures revealed the synthesized nano-GDC powders had superior sinterability compared to commercial GDC powders (e.g., 96% vs 78% in relative density at 1300 °C, respectively). Based on the total conductivity measurement of the co-precipitated GDC via electrochemical impedance spectroscopy, we found there was an optimum sintering temperature range (1300-1400 °C) to achieve both high density and high conductivity due to significant increase in grain boundary resistance at higher temperature (1500 °C). Moreover, the nano-sized and highly sinterable co-precipitated GDC effectively enhanced oxygen reduction reaction at the La0.6Sr0.4Co0.2Fe0.8O3-δ/GDC composite cathode due to increase in active reaction sites as well as enhanced phase connectivity in 3D-bulk at lower sintering temperatures. © 2016 Elsevier B.V. All rights reserved.