2,000 research outputs found

    A smart transformer-rectifier unit for the more electric aircraft

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    In the framework of the More Electric Aircraft (MEA), an efficient and flexible power distribution system is of paramount importance. Considering the presence of both AC and DC loads at multiple voltage levels, the distribution system of the most modern aircrafts is intrinsically hybrid. In this scenario, the different buses are connected by AC/DC converters. The simplest approach is to use a Transformer-Rectifier Unit (TRU) based on a low-frequency transformer followed by passive rectifiers to perform the AC/DC conversion. This solution, however, is intrinsically uni-directional, introduces current harmonics in the AC side and can have a considerable size. This paper proposes the use of a Smart-TRU, based on a Cascaded H-Bridge topology and a multi-port DC/DC converter, to solve the issues of the traditional TRU, increasing the controllability of the system. Experiments show how the proposed STRU is resilient to faults in the AC side

    A comparison of the clinical outcomes of patients with invasive lobular carcinoma and invasive ductal carcinoma of the breast according to molecular subtype in a Korean population

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    BACKGROUND: To investigate the clinicopathological characteristics and the survival outcomes of invasive lobular carcinoma (ILC) patients compared to invasive ductal carcinoma (IDC) patients according to their molecular subtype. METHODS: We compared the clinicopathological characteristics, breast cancer-specific survival (BCSS) and overall survival (OS) between patients with IDC (n = 14,547) and ILC (n = 528). RESULTS: The ILC presented with a larger tumor size, more advanced cancer stage, increased rate of hormonal receptor positivity, human epidermal growth factor 2 (HER2) negativity and mastectomy than the IDC. The ILC patients more frequently presented with the luminal A subtype, whereas the IDC patients more frequently presented with the luminal B, HER2-overexpression, or triple negative subtype. The BCSS and OS were not significantly different between the IDC and ILC for each molecular subtype. CONCLUSIONS: Similar to IDC patients, molecular subtype should be considered when determining the prognosis and treatment regimen for ILC patients

    Development of software for computing forming information using a component based approach

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    ABSTRACTIn shipbuilding industry, the manufacturing technology has advanced at an unprecedented pace for the last decade. As a result, many automatic systems for cutting, welding, etc. have been developed and employed in the manufacturing process and accordingly the productivity has been increased drastically. Despite such improvement in the manufacturing technology, however, development of an automatic system for fabricating a curved hull plate remains at the beginning stage since hardware and software for the automation of the curved hull fabrication process should be developed differently depending on the dimensions of plates, forming methods and manufacturing processes of each shipyard. To deal with this problem, it is necessary to create a “plug-in” framework, which can adopt various kinds of hardware and software to construct a full automatic fabrication system. In this paper, a framework for automatic fabrication of curved hull plates is proposed, which consists of four components and related software. In particular the software module for computing fabrication information is developed by using the ooCBD development methodology, which can interface with other hardware and software with minimum effort. Examples of the proposed framework applied to medium and large shipyards are presented

    Numerical Analysis of IEEE 802.11 Broadcast Scheme in Multihop Wireless Ad Hoc Networks

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    Abstract. In this paper, we study the performance of IEEE 802.11 broadcast scheme in multihop wireless networks using an analytical model. Previous works have evaluated the performance of IEEE 802.11 proto-col assuming unicast communication, but there has not been an analysis considering broadcast communication. Analyzing performance of broad-cast communication is important because multicast communication is gaining attention in wireless networks with numerous potential applica-tions. Broadcast in IEEE 802.11 does not use virtual carrier sensing and thus only relies on physical carrier sensing to reduce collision. For this study, we define a successful broadcast transmission to be the case when all of the sender’s neighbors receive the broadcast frame correctly, and calculate the achievable throughput.

    Anti-inflammatory effect and mechanism of action of Lindera erythrocarpa essential oil in lipopolysaccharide-stimulated RAW264.7 cells

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    The aim of this study was to investigate the chemical constituents of Lindera erythrocarpa essential oil (LEO) by gas chromatography-mass spectrometry and evaluate their inhibitory effect on the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Fifteen compounds, accounting for 63.7 % of the composition of LEO, were identified. The main compounds were nerolidol (18.73 %), caryophyllene (14.41 %), α-humulene (7.73 %), germacrene-D (4.82 %), and α-pinene (4.47 %). LEO significantly inhibited the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, and subsequent production of NO and prostaglandin E2. In addition, it reduced the release of pro-inflammatory cytokines in LPS-activated RAW264.7 cells. The molecular mechanism underlying the effect of LEO was associated with inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK). Furthermore, LEO inhibited LPS-induced phosphorylation and degradation of inhibitor of kappa B-α, which is required for the activation of the p50 and p65 nuclear factor (NF)-κB subunits in RAW264.7 cells. Taken together, these data suggest that LEO exerted its anti-inflammatory effect by downregulating LPS-induced production of pro-inflammatory mediators through the inhibition of NF-κB and MAPK signaling in RAW264.7 cells

    Helicobacter pylori Infection and Halitosis – Evidence, Hypothesis, and Korean Red Ginseng to Mitigate Its Effect

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    Halitosis is a common and ignored condition, but in some, it is a disease-associated health problem, suggestive of overt disease conditions and hasaffected about 25–30% of world’s population, bothering nonmedical social disturbance in many people. Although two kinds, pseudohalitosis and halitophobia, are also concerned, genuine halitosis originated from the oral cavity, such as gingivitis, caries, and poor oral hygiene, in 80% and the remaining 20% are extraoral sources of halitosis, which should not be ignored because of stigmata suggestive of overt tissue dysfunctions, for instance, poor nutrition and hygiene, alcohol abuse, smoking, and systemic illness such as chronic obstructive pulmonary disease, liver cirrhosis, diabetes mellitus, and chronic renal diseases. In this chapter, Helicobacter pylori (H. pylori)–associated halitosis as one of the extragastric manifestations is introduced. Since diagnostics of halitosis includes subjective methods (examiner’s sense of smell) and objective methods (instrumental analysis), under the hypothesis of a possible relationship between H. pylori infection and objective halitosis, the real levels of volatile sulfur compounds (VSCs) in the breath showed significant correlation between VSC levels and the degree of H. pylori–associated erosive gastritis as well as gastric cancer. These findings are further validated through either measuring H2S level in gastric juices of H. pylori–infected gastritis or checking the expressions of cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS) responsible for H2S generation in biopsied stomach. The eradication of H. pylori significantly ameliorated halitosis, accompanied with significant reductions in gastric H2S levels (p<0.01). Korean red ginseng was very effective in either reducing H. pylori–associated H2S or alleviating halitosis in patients with H. pylori–associated chronic atrophic gastritis. Conclusively, H. pylori infection demonstrates to have an important relationship with the development of halitosis, and its eradication could possibly promote the improvement of this condition

    Respiratory Syncytial Virus-Like Nanoparticle Vaccination Induces Long-Term Protection Without Pulmonary Disease by Modulating Cytokines and T-cells Partially Through Alveolar Macrophages

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    The mechanisms of protection against respiratory syncytial virus (RSV) are poorly understood. Virus-like nanoparticles expressing RSV glycoproteins (eg, a combination of fusion and glycoprotein virus-like nanoparticles [FG VLPs]) have been suggested to be a promising RSV vaccine candidate. To understand the roles of alveolar macrophages (AMs) in inducing long-term protection, mice that were 12 months earlier vaccinated with formalin-inactivated RSV (FI-RSV) or FG VLPs were treated with clodronate liposome prior to RSV infection. FI-RSV immune mice with clodronate liposome treatment showed increases in eosinophils, plasmacytoid dendritic cells, interleukin (IL)-4+ T-cell infiltration, proinflammatory cytokines, chemokines, and, in particular, mucus production upon RSV infection. In contrast to FI-RSV immune mice with severe pulmonary histopathology, FG VLP immune mice showed no overt sign of histopathology and significantly lower levels of eosinophils, T-cell infiltration, and inflammatory cytokines, but higher levels of interferon-Îł, which are correlated with protection against RSV disease. FG VLP immune mice with depletion of AMs showed increases in inflammatory cytokines and chemokines, as well as eosinophils. The results in this study suggest that FG nanoparticle vaccination induces long-term protection against RSV and that AMs play a role in the RSV protection by modulating eosinophilia, mucus production, inflammatory cytokines, and T-cell infiltration

    Outcomes of endovascular treatment for aortic pseudoaneurysm in Behcet's disease

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    ObjectiveTo evaluate the effectiveness of endovascular stent grafting for surgical management of aortic pseudoaneurysm in patients with Behcet's disease (BD).MethodsWe present a single-institution retrospective cohort of patients with aortic pseudoaneurysm and BD treated with aortic stent grafting. Computed tomography imaging was obtained preoperatively in all patients and once within 2 weeks postoperatively, and then annually. Clinical follow-up and erythrocyte sedimentation rate were used to follow BD activity. Immunosuppressant therapy was instituted prior to endovascular treatment unless a contraindication existed.ResultsFrom 1998 to 2012, 10 patients (eight male, two female; median age, 39) with BD and aortic pseudoaneurysm were treated with endovascular stent grafting at this institution. Ninety percent of these patients received immunosuppressive therapy before and after surgical treatment. The median follow-up period was 57 months (interquartile range, 43-72). The locations of the 12 pseudoaneurysms treated in this cohort were infrarenal abdominal aorta (seven), descending thoracic aorta (four), and aortic arch (one). Median pseudoaneurysm size was 4.5 cm (interquartile range, 3.4-5.9). At long-term follow-up, complete resolution of the aortic pseudoaneurysm was noted in all patients. No endoleaks occurred. Newly developed pseudoaneurysm at the distal margin of the stent graft was noted in one patient 17 months after the stent graft procedure. One patient required a subsequent stent graft placement for an expanding pseudoaneurysm of the subclavian artery. No patient deaths occurred during the follow-up period.ConclusionsEndovascular treatment of aortic pseudoaneurysm with stent-grafting in patients with BD is safe and effective with long-term durability
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