1,215 research outputs found
Large-Scale Plasma Polymer Coating on Heat Exchanger Fins for Improving the Wettability
This research presents the results of the recently developed large-scale hydrophilic polymer coating by plasma polymerization, optimum plasma zone (OPZ) process. The excellent hydrophilicity of heat exchanger fin surface could give good effects to efficient drainage of condensate water as well as heat transfer performance. The hydrophilicity of layer treated by large-scale OPZ system is excellent irrespective of line speed from 0.6 m/min to 2.4 m/min. The good lateral uniformity of the hydrophilicity could be acquired in large scale OPZ treatment. The application of OPZ technique to the heat exchanger could enhance the efficiency of heat transfer, resulting from decrease of pressure drop. Due to long-term durability of hydrophilicity, the heat transfer performance improved by OPZ process cannot be deteriorated with operation cycle
Determination of bit-rate and sensitivity limits of an optimized p-i-n/HBT OEIC receiver using SPICE simulations
The sensitivity of an OEIC receiver depends essentially
on the physical sources of device and circuit noise referred
to its input, provided that the inter-symbol interference (ISI)
makes no significant contribution. For well designed receivers,
the latter situation can be realized only at an optimum bandwidth
(f3 dB-opt) for a given bit rate (B) or vice versa. In this paper,
we have determined the relationship between the bit rate and
the 3-dB bandwidth for negligible and pre-set levels of ISI for
an optimized p-i-n/HBT transimpedance receiver with adjustable
bandwidth.We have used the SPICE simulations in the frequency
domain to determine the effect of device and circuit noise, and
the SPICE transient analysis to determine the effect of ISI on the
sensitivity. The ratio f3 dB-opt=B has been found to vary from
0.65 to 0.45 when B changes from 10 to 20 Gbps for the OEIC
receiver used.This work was
supported by the Korean Science and Engineering Foundation under Grant
94-X-0026, by the KAIST OptoElectronics Research Center (OERC), and
also by the U.S. National Science Foundation under Grant ECS-9541739
(INT-9412658). The work of S. J. Kim was supported in part by the SeoAm
Scholarship Foundation
Quantitative agreement of Dzyaloshinskii-Moriya interactions for domain-wall motion and spin-wave propagation
The magnetic exchange interaction is the one of the key factors governing the
basic characteristics of magnetic systems. Unlike the symmetric nature of the
Heisenberg exchange interaction, the interfacial Dzyaloshinskii-Moriya
interaction (DMI) generates an antisymmetric exchange interaction which offers
challenging opportunities in spintronics with intriguing antisymmetric
phenomena. The role of the DMI, however, is still being debated, largely
because distinct strengths of DMI have been measured for different magnetic
objects, particularly chiral magnetic domain walls (DWs) and non-reciprocal
spin waves (SWs). In this paper, we show that, after careful data analysis,
both the DWs and SWs experience the same strength of DMI. This was confirmed by
spin-torque efficiency measurement for the DWs, and Brillouin light scattering
measurement for the SWs. This observation, therefore, indicates the unique role
of the DMI on the magnetic DW and SW dynamics and also guarantees the
compatibility of several DMI-measurement schemes recently proposed.Comment: 24 pages, 5 figure
Image quality and attenuation values of multi detector CT coronary angiography using high iodine-concentration contrast material: A comparison of the use of iopromide 370 and iomeprol 400
Background: Effects of high iodine-concentration contrast material on the image quality of coronary CT angiography (CCTA) have not been well evaluated
Cyclooxygenase-2 and p53 Expression as Prognostic Indicators in Conventional Renal Cell Carcinoma
The aim of this study was to investigate the relationship of cyclooxygenase (COX)-2 and p53 expression with prognosis in patients with conventional renal cell carcinoma (RCC). Formalin-fixed, paraffin-embedded tissue sections of conventional RCC from 92 patients, who had undergone radical nephrectomy, were examined for COX-2 and p53 expression by immunohistochemistry and compared with clinicopathological variables. The COX-2 expression significantly correlated only with tumor size (p=0.049), whereas the p53 expression profoundly correlated with the TNM stage (p=0.024), M stage (p=0.001), and metastasis (synchronous or metachronous; p=0.004). The COX-2 overexpression did not significantly associate with p53 positivity (p=0.821). The survival rate of patients correlated with the p53 expression (p<0.0001) but not with the COX-2 expression (p=0.7506). Multivariate analyses indicated that tumor size, M stage, and p53 expression were independent prognostic factors for cancer-specific survival. The COX-2 expression was not an independent factor. These results show that the increased expression of p53 was associated with metastasis and a worse prognosis in conventional RCC, which suggests that p53 might have played an important role in the progression of conventional RCC. The increased expression of COX-2 was associated only with tumor size, but may not be an important prognostic factor in conventional RCC. No association was observed between COX-2 overexpression and p53 positivity in conventional RCC
Sorbus alnifolia protects dopaminergic neurodegeneration in Caenorhabditis elegans
Context: The twigs of Sorbus alnifolia (Sieb. et Zucc.) K. Koch (Rosaceae) have been used to treat neuro- logical disorders as a traditional medicine in Korea. However, there are limited data describing the efficacy of S. alnifolia in Parkinson’s disease (PD).
Objective: This study was conducted to identify the protective effects of the methanol extracts of S. alnifolia (MESA) on the dopaminergic (DA) neurodegeneration in Caenorhabditis elegans.
Materials and methods: To test the neuroprotective action of MESA, viability assay was performed after 48 h exposure to 1-methyl-4-phenylpyridine (MMPþ) in PC12 cells and C. elegans (400 lM and 2 mM of MMPþ, respectively). Fluorescence intensity was quantified using transgenic mutants such as BZ555 (Pdat-1::GFP) and and UA57 (Pdat-1::GFP and Pdat-1::CAT-2) to determine MESA’s effects on DA neurode- generation in C. elegans. Aggregation of a-synuclein was observed using NL5901 strain (unc-54p::a- synuclein::YFP). MESA’s protective effects on the DA neuronal functions were examined by food-sensing assay. Lifespan assay was conducted to test the effects of MESA on the longevity.
Results: MESA restored MPPþ-induced loss of viability in both PC12 cells and C. elegans (85.8% and 54.9%, respectively). In C. elegans, MESA provided protection against chemically and genetically-induced DA neurodegeneration, respectively. Moreover, food-sensing functions were increased 58.4% by MESA in the DA neuron degraded worms. MESA also prolonged the average lifespan by 25.6%. However, MESA failed to alter a-synuclein aggregation.
Discussion and conclusions: These results revealed that MESA protects DA neurodegeneration and recov- ers diminished DA neuronal functions, thereby can be a valuable candidate for the treatment of PD
KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model
AbstractKAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models
Chylothorax in Gorham's disease.
A 25-yr-old woman presented with a right pleural effusion. Destruction of 9th through 12th ribs, adjacent vertebral bodies, and transverse processes was noted on plain radiograph and a large low-attenuated, irregular shaped mass lesion with peripheral rim enhancement, destroying vertebral body and transverse process, was revealed on the computed tomographic scan. Magnetic resonance imaging showed high signal on T1- weighted image and iso- and low signal on T2-weighted image for the mass lesion replacing the vertebral bony cortex and marrow space. An open rib biopsy revealed the histopathological changes of Gorham's disease (essential osteolysis), even though only bloody fluid filling the empty space and rib and vertebral transverse process destruction were grossly observed on operation. Even though there was no definite response to radiotherapy and pleurodesis, the patient showed stable condition up to 20 months after diagnosis
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