1,008 research outputs found

    Radiating Shear-Free Gravitational Collapse with Charge

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    We present a new shear free model for the gravitational collapse of a spherically symmetric charged body. We propose a dissipative contraction with radiation emitted outwards. The Einstein field equations, using the junction conditions and an ansatz, are integrated numerically. A check of the energy conditions is also performed. We obtain that the charge delays the black hole formation and it can even halt the collapse.Comment: 22 pages, 9 figures. It has been corrected several typos and included several references. Accepted for publication in GR

    Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

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    Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (similar to 97.5 cd/A, similar to 35.5% photons per electron), green (similar to 101.5 cd/A, similar to 29.0% photons per electron), and white (similar to 74.2 cd/A, similar to 28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices.

    Mechanical Properties and Durability of Latex-Modified Fiber-Reinforced Concrete: A Tunnel Liner Application

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    This study assessed the mechanical properties and durability of latex-modified fiber-reinforced segment concrete (polyolefin-based macrosynthetic fibers and hybrid fiber-macrosynthetic fiber and polypropylene fiber) for a tunnel liner application. The tested macrosynthetic fiber-reinforced concrete has a better strength than steel fiber-reinforced concrete. The tested concrete with blast furnace slag has a higher chloride ion penetration resistance (less permeable), but its compressive and flexural strengths can be reduced with blast furnace slag content increase. Also, the hybrid fiber-reinforced concrete has higher compressive strength, flexural strength, chloride ion water permeability resistance, impact resistance, and abrasion resistance than the macrosynthetic fiber-reinforced concrete. The modified fiber improved the performance of concrete, and the hybrid fiber was found to control the formation of micro- and macrocracks more effectively. Therefore, overall performance of the hybrid fiber-reinforced concrete was found superior to the other fiber-reinforced concrete mixes tested for this study. The test results also indicated that macrosynthetic fiber could replace the steel fiber as a concrete reinforcement

    Complete response to FOLFOX4 therapy in a patient with advanced urothelial cancer: a case report

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    No standard has been established for salvage therapy in gemcitabine refractory advanced urothelial cancer. We report the complete response to FOLFOX4 therapy of a metastatic urothelial cancer patient, for whom adjuvant gemcitabine plus cisplatin combination chemotherapy had failed. A 54-year-old male patient with urothelial cancer (transitional cell carcinoma) in the right kidney underwent three rounds of adjuvant gemcitabine-cisplatin chemotherapy after extensive radical nephrectomy. However, he had new liver, lung metastases and synchronous two separate primary colon cancer. The lung metastasis lesion was confirmed as a metastatic urothelial cancer via percutaneous transthoracic needle biopsy (PTNB). Liver and lung metastasis lesions disappeared after the 4th cycle of FOLFOX4 chemotherapy. In addition, colon cancer also disappeared after the 8th cycle of FOLFOX4 chemotherapy. The patient was still showing a complete response after 4 months. Clinical trials using the FOLFOX regimen as salvage therapy for gemcitabine-refractory advanced urothelial cancer are warranted

    Molecular analysis of WWOX expression correlation with proliferation and apoptosis in glioblastoma multiforme

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    Glioblastoma multiforme is the most common type of primary brain tumor in adults. WWOX is a tumor suppressor gene involved in carcinogenesis and cancer progression in many different neoplasms. Reduced WWOX expression is associated with more aggressive phenotype and poor patient outcome in several cancers. We investigated alternations of WWOX expression and its correlation with proliferation, apoptosis and signal trafficking in 67 glioblastoma multiforme specimens. Moreover, we examined the level of WWOX LOH and methylation status in WWOX promoter region. Our results suggest that loss of heterozygosity (relatively frequent in glioblastoma multiforme) along with promoter methylation may decrease the expression of this tumor suppressor gene. Our experiment revealed positive correlations between WWOX and Bcl2 and between WWOX and Ki67. We also confirmed that WWOX is positively correlated with ErbB4 signaling pathway in glioblastoma multiforme

    Laparoscopic splenectomy for sclerosing angiomatoid nodular transformation of the spleen

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    Primary splenic tumors are rare and mainly found incidentally on radiologic studies. Among them, sclerosing angiomatoid nodular transformation (SANT) of the spleen is a new entity defined as a benign pathologic lesion. Most SANTs have no clinical symptoms and are occasionally accompanied by other splenic diseases such as malignancies. So, the exact diagnosis of the nature of the splenic tumor is mandatory for further treatment. But, preoperative diagnosis is not easy since it is difficult to obtain the tissue from the spleen for pathological study. Recently, laparoscopic splenectomy has become the more standard procedure for the spleen for diagnosis and treatment. Here, we report a rare case of SANT diagnosed following laparoscopic splenectomy

    Genome-based analysis for the bioactive potential of Streptomyces yeochonensis CN732, an acidophilic filamentous soil actinobacterium

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    Acidophilic members of the genus Streptomyces can be a good source for novel secondary metabolites and degradative enzymes of biopolymers. In this study, a genome-based approach on Streptomyces yeochonensis CN732, a representative neutrotolerant acidophilic streptomycete, was employed to examine the biosynthetic as well as enzymatic potential, and also presence of any genetic tools for adaptation in acidic environment. A high quality draft genome (7.8 Mb) of S. yeochonensis CN732 was obtained with a G + C content of 73.53% and 6549 protein coding genes. The in silico analysis predicted presence of multiple biosynthetic gene clusters (BGCs), which showed similarity with those for antimicrobial, anticancer or antiparasitic compounds. However, the low levels of similarity with known BGCs for most cases suggested novelty of the metabolites from those predicted gene clusters. The production of various novel metabolites was also confirmed from the combined high performance liquid chromatography-mass spectrometry analysis. Through comparative genome analysis with related Streptomyces species, genes specific to strain CN732 and also those specific to neutrotolerant acidophilic species could be identified, which showed that genes for metabolism in diverse environment were enriched among acidophilic species. In addition, the presence of strain specific genes for carbohydrate active enzymes (CAZyme) along with many other singletons indicated uniqueness of the genetic makeup of strain CN732. The presence of cysteine transpeptidases (sortases) among the BGCs was also observed from this study, which implies their putative roles in the biosynthesis of secondary metabolites. This study highlights the bioactive potential of strain CN732, an acidophilic streptomycete with regard to secondary metabolite production and biodegradation potential using genomics based approach. The comparative genome analysis revealed genes specific to CN732 and also those among acidophilic species, which could give some insights into the adaptation of microbial life in acidic environment

    Clinical significance of preoperative serum vascular endothelial growth factor, interleukin-6, and C-reactive protein level in colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>Angiogenesis is a multistep process in which many growth factors and cytokines have an essential role. Vascular endothelial growth factor (VEGF) is a potent angiogenic agent that acts as a specific mitogen for vascular endothelial cells through specific cell surface receptors. The interleukin-6 (IL-6) pathway is another mechanism linking angiogenesis to malignancy. C-reactive protein (CRP), a representative marker for inflammation, is known for its association with disease progression in many cancer types. The aim of this study was to determine preoperative serum levels of VEGF, IL-6, and CRP in colorectal carcinoma, and to correlate them with disease status and prognosis.</p> <p>Methods</p> <p>A 132 of 143 patients who underwent curative resection for colorectal cancer were enrolled in this study. 11 patients with resection margin positive were excluded. Factors considered in analysis of the relationship between VEGF, IL-6, and CRP and histological findings. Patient prognosis was investigated. Serum levels of VEGF and IL-6 were assessed using Enzyme-Linked Immuno-Sorbent Assay (ELISA), and CRP was measured using immunoturbidimetry.</p> <p>Results</p> <p>Median follow-up duration was 18.53 months (range 0.73-43.17 months) and median age of the patients was 62 years (range, 26-83 years). Mean and median levels of VEGF and CRP in colorectal cancer were significantly higher than in the normal control group; 608 vs. 334 pg/mL and 528 (range 122-3242) vs. 312 (range 16-1121) (<it>p </it>< 0.001); 1.05 mg/dL vs. 0.43 mg/dL and 0.22 (range 0.00-18.40) vs. 0.07 (range 0.02-6.94) (<it>p </it>= 0.002), respectively. However mean and median level of IL-6 in patients were not significantly higher than in control; 14.33 pg/mL vs. 5.65 pg/mL and 6.00 (range 1.02-139.17) vs. 5.30 (4.50-13.78) (<it>p </it>= 0.327). Although IL-6 and CRP levels were not correlated with other pathological findings, VEGF level was significantly correlated with tumor size (<it>p </it>= 0.012) and CEA (<it>p </it>= 0.038). When we established the cutoff value for VEGF (825 pg/mL), IL-6 (8.09 pg/mL), and CRP (0.51 mg/dL) by Receiver Operating Characteristic (ROC) curve, we noted that high VEGF levels tended to reduce overall survival (<it>p </it>= 0.053), but not significantly. However, IL-6 and CRP demonstrated no significance with regard to disease free survival (<it>p </it>= 0.531, <it>p </it>= 0.701, respectively) and overall survival (<it>p </it>= 0.563, <it>p </it>= 0.572, respectively). Multivariate analysis showed that VEGF (<it>p </it>= 0.032), CEA (<it>p </it>= 0.012), lymph node metastasis (<it>p </it>= 0.002), and TNM stage (<it>p </it>= 0.025) were independently associated with overall survival.</p> <p>Conclusions</p> <p>Preoperative serum VEGF and CRP level increased in colorectal cancer patients. High VEGF level has been proposed as a poor prognostic factor for overall survival in patients with colorectal cancer.</p

    Ezrin interacts with the SARS coronavirus spike protein and restrains infection at the entry stage

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    © 2012 Millet et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Entry of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and its envelope fusion with host cell membrane are controlled by a series of complex molecular mechanisms, largely dependent on the viral envelope glycoprotein Spike (S). There are still many unknowns on the implication of cellular factors that regulate the entry process. Methodology/Principal Findings: We performed a yeast two-hybrid screen using as bait the carboxy-terminal endodomain of S, which faces the cytosol during and after opening of the fusion pore at early stages of the virus life cycle. Here we show that the ezrin membrane-actin linker interacts with S endodomain through the F1 lobe of its FERM domain and that both the eight carboxy-terminal amino-acids and a membrane-proximal cysteine cluster of S endodomain are important for this interaction in vitro. Interestingly, we found that ezrin is present at the site of entry of S-pseudotyped lentiviral particles in Vero E6 cells. Targeting ezrin function by small interfering RNA increased S-mediated entry of pseudotyped particles in epithelial cells. Furthermore, deletion of the eight carboxy-terminal amino acids of S enhanced S-pseudotyped particles infection. Expression of the ezrin dominant negative FERM domain enhanced cell susceptibility to infection by SARS-CoV and S pseudotyped particles and potentiated S-dependent membrane fusion. Conclusions/Significance: Ezrin interacts with SARS-CoV S endodomain and limits virus entry and fusion. Our data present a novel mechanism involving a cellular factor in the regulation of S-dependent early events of infection.This work was supported by the Research Grant Council of Hong Kong (RGC#760208)and the RESPARI project of the International Network of Pasteur Institutes
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