5,135 research outputs found
Growth of superconducting MgB2 thin films via postannealing techniques
We report the effect of annealing on the superconductivity of MgB2 thin films
as functions of the postannealing temperature in the range from 700 C to 950 C
and of the postannealing time in the range from 30 min to 120 min. On annealing
at 900 C for 30 min, we obtained the best-quality MgB2 films with a transition
temperature of 39 K and a critical current density of ~ 10^7 A/cm^2. Using the
scanning electron microscopy, we also investigated the film growth mechanism.
The samples annealed at higher temperatures showed the larger grain sizes,
well-aligned crystal structures with preferential orientations along the
c-axis, and smooth surface morphologies. However, a longer annealing time
prevented the alignment of grains and reduced the superconductivity, indicating
a strong interfacial reaction between the substrate and the MgB2 film.Comment: 7 pages, 4 figures include
Transfer of Korean Manner Assimilation to English
The purpose of this study is to examine the transfer of manner assimilation
phenomena from Korean into English. The data from this study showed that three types of manner assimilation in Korean are not transferred to the same degree. That is, obstruent-nasalization and lateralization were readily carried over to the subjects' interlanguage, while the transfer of liquid-nasalization was noticeably low. Following the positional faithfulness of the syllable onset, liquid-nasalization is considered to be a marked phenomenon. Recent transfer studies have found that phonetically motivated processes, such as obstruent-nasalization and lateralizaiton, are more easily carried over to the target language than the lexically restricted morphophonological processes like liquid-nasalization. This suggests that the reason for the discrepancy in transfer rates lies in the difference of status among
the three processes, tempered by a morphophonological rule of avoidance of word-initial liquids, which in turn implies that the syllable contact constraint is not the only reason for manner assimilation in Korean
Efficiency Analysis of Major Container Ports in Asia: Using DEA and Shannon’s Entropy
This paper attempts to evaluate performance (i.e. efficiency) of Asias container ports. Measurement of the ports performance is critical to increase the competitiveness of maritime transport, ultimately leading to one nations competitive advantages over other countries. Data Envelopment Analysis (DEA), which is a non-parametric method widely used for assessing efficiency of units which have similar characteristics, was selected to analyse the data. Due to the limitations of the DEA method producing diverse results according to different models, and to the complexities of choosing a specific model among several DEA models, Shannons Entropy was also employed. By including Shannons Entropy, the efficiency results calculated from each model were integrated in order to rank the ports. The results in this study will provide port managers with valuable information in order to understand the current status of Asias container ports in terms of their efficiency
Red pepper seed water extract inhibits preadipocyte differentiation and induces mature adipocyte apoptosis in 3T3-L1 cells
BACKGROUND/OBJECTIVES: Reducing the number of adipocytes by inducing apoptosis of mature adipocytes as well as suppressing differentiation of preadipocytes plays an important role in preventing obesity. This study examines the anti-adipogenic and pro-apoptotic effect of red pepper seed water extract (RPS) prepared at 4°C (RPS4) in 3T3-L1 cells.
MATERIALS/METHODS: Effect of RPS4 or its fractions on lipid accumulation was determined in 3T3-L1 cells using oil red O (ORO) staining. The expressions of AMP-activated protein kinase (AMPK) and adipogenic associated proteins [peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding proteins α (C/EBP α), sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC)] were measured in 3T3-L1 cells treated with RPS4. Apoptosis and the expression of Akt and Bcl-2 family proteins [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad), Bcl-2 like protein 4 (Bax), Bal-2 homologous antagonist/killer (Bak)] were measured in mature 3T3-L1 cells treated with RPS4.
RESULTS: Treatment of RPS4 (0-75 ug/mL) or its fractions (0-50 ug/mL) for 24 h did not have an apparent cytotoxicity on pre and mature 3T3-L1 cells. RPS4 significantly suppressed differentiation and cellular lipid accumulation by increasing the phosphorylation of AMPK and reducing the expression of PPAR-γ, C/EBP α, SREBP-1c, FAS, and ACC. In addition, all fractions except ethyl acetate fraction significantly suppressed cellular lipid accumulation. RPS4 induced the apoptosis of mature adipocytes by hypophosphorylating Akt, increasing the expression of the pro-apoptotic proteins, Bak, Bax, and Bad, and reducing the expression of the anti-apoptotic proteins, Bcl-2 and p-Bad.
CONCLUSIONS: These finding suggest that RPS4 can reduce the numbers as well as the size of adipocytes and might useful for preventing and treating obesity
TCF/β-catenin plays an important role in HCCR-1 oncogene expression
<p>Abstract</p> <p>Background</p> <p>Oncogene <it>HCCR-1 </it>functions as a negative regulator of the p53 and contributes to tumorigenesis of various human tissues. However, it is unknown how <it>HCCR-1 </it>contributes to the cellular and biochemical mechanisms of human tumorigenesis.</p> <p>Results</p> <p>In this study, we showed how the expression of <it>HCCR-1 </it>is modulated. The luciferase activity assay indicated that the <it>HCCR-1 </it>5'-flanking region at positions -166 to +30 plays an important role in <it>HCCR-1 </it>promoter activity. Computational analysis of this region identified two consensus sequences for the T-cell factor (TCF) located at -26 to -4 (Tcf1) and -136 to -114 (Tcf2). Mutation at the Tcf1 site led to a dramatic decrease in promoter activity. Mobility shift assays (EMSA) revealed that nuclear proteins bind to the Tcf1 site, but not to the Tcf2 site. LiCl, Wnt signal activator by GSK-3β inhibition, significantly increased reporter activities in wild-type Tcf1-containing constructs, but were without effect in mutant Tcf1-containing constructs in HEK/293 cells. In addition, endogenous <it>HCCR-1 </it>expression was also increased by treatment with GSK-3β inhibitor, LiCl or AR-A014418 in HEK/293 and K562 cells. Finally, we also observed that the transcription factor, TCF, and its cofactor, β-catenin, bound to the Tcf1 site.</p> <p>Conclusion</p> <p>These findings suggest that the Tcf1 site on the <it>HCCR-1 </it>promoter is a major element regulating <it>HCCR-1 </it>expression and abnormal stimulation of this site may induce various human cancers.</p
The diagnosis of an imperforate anus in female fetuses
Imperforate anus is an anomaly caused by a defect in the development of the hindgut during early pregnancy. It is a relatively common congenital malformation and is more common in males. Although there are cases of a solitary imperforate anus, the condition is more commonly found as a part of a wider spectrum of other congenital anomalies. Although urgent reconstructive anorectal surgery is not necessary, immediate evaluation is important and urgent decompressive surgery may be required. Moreover, as there are often other anomalies that can affect management, prenatal diagnosis can help in optimizing perinatal care and prepare parents through prenatal counseling. In the past, imperforate anus was diagnosed by prenatal ultrasonography based on indirect signs such as bowel dilatation or intraluminal calcified meconium. Currently, it is diagnosed by directly checking the perineum with prenatal ultrasonography. Despite advances in ultrasound technology, accurate prenatal diagnosis is impossible in most cases and imperforate anus is detected after birth. Here, we present two cases of imperforate anus in female fetuses that were not diagnosed prenatally
St. John’s Wort Regulates Proliferation and Apoptosis in MCF-7 Human Breast Cancer Cells by Inhibiting AMPK/mTOR and Activating the Mitochondrial Pathway
St. John’s Wort (SJW) has been used as an estrogen agonist in the systems affected by menopause. Also, hypericin, a bioactive compound of SJW, has been used as a photosensitizer in photodynamic therapy. In the present study, we investigate the anti-proliferative and pro-apoptotic effects of SJWto demonstrate the chemo-preventive effect in human breast cancer cells. MCF-7 cellswere culturedwith DMSO or various concentrations of SJWethanol extract (SJWE). Cell viability, proliferation, apoptosis, the expression of proteins involved in cell growth and apoptosis, and caspase-3/7 activity were examined. SJWE dose-dependently suppressed cell growth and induced apoptosis ofMCF-7 cells. Mechanistically, SJWE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and decreased the expression of p-mammalian target of rapamycin (p-mTOR) and p-eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). Also, SJWE inhibited the phosphorylation of protein kinase B (Akt) and showed increases in the expression of pro-apoptotic proteins Bax and Bad with decreases in the expression of anti-apoptotic proteins including B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), and p-Bcl-2-associated death promoter (p-Bad). SJWE at 50 µg/mL showed markedly enhanced caspase-7 activation. Taken together, our results provide evidence that SJWE shows anti-proliferative and pro-apoptotic effects via inhibition of AMPK/mTOR and activation of a mitochondrial pathway. Therefore, SJWE can be used as a chemo-preventive agent without photo-activation
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