Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamental frequency. In this paper, we analyze the variation in frequency of ultra-high frequency nano-mechnical resonators constructed from DWCNTs with different wall lengths

Three-dimensional flow phenomena in a wire-wrapped 37-pin fuel bundle for SFR

AbstractThree-dimensional flow phenomena in a wire-wrapped 37-pin fuel assembly mock-up of a Japanese loop-type sodium-cooled fast reactor, Monju, were investigated with a numerical analysis using a general-purpose commercial computational fluid dynamics code, CFX. Complicated and vortical flow phenomena in the wire-wrapped 37-pin fuel assembly were captured by a Reynolds-averaged Navier–Stokes flow simulation using a shear stress transport turbulence model. The main purpose of the current study is to understand the three-dimensional complex flow phenomena in a wire-wrapped fuel assembly to support the license issue for the core design. Computational fluid dynamics results show good agreement with friction factor correlation models. The secondary flow in the corner and edge subchannels is much stronger than that in an interior subchannel. The axial velocity averaged in the corner and edge subchannels is higher than that averaged in the interior subchannels. Three-dimensional multiscale vortex structures start to be formed by an interaction between secondary flows around each wire-wrapped pin. Behavior of the large-scale vortex structures in the corner and edge subchannels is closely related to the relative position between the hexagonal duct wall and the helically wrapped wire spacer. The small-scale vortex is axially developed in the interior subchannels. Furthermore, a driving force on each wire spacer surface is closely related to the relative position between the hexagonal duct wall and the wire spacer

Glucose repression of the Escherichia coli sdhCDAB operon, revisited: regulation by the CRP·cAMP complex

Expression of the Escherichia coli sdhCDAB operon encoding the succinate dehydrogenase complex is regulated in response to growth conditions, such as anaerobiosis and carbon sources. An anaerobic repression of sdhCDAB is known to be mediated by the ArcB/A two-component system and the global Fnr anaerobic regulator. While the cAMP receptor protein (CRP) and Cra (formerly FruR) are known as key mediators of catabolite repression, they have been excluded from the glucose repression of the sdhCDAB operon. Although the glucose repression of sdhCDAB was reported to involve a mechanism dependent on the ptsG expression, the molecular mechanism underlying the glucose repression has never been clarified. In this study, we re-examined the mechanism of the sdhCDAB repression by glucose and found that CRP directly regulates expression of the sdhCDAB operon and that the glucose repression of this operon occurs in a cAMP-dependent manner. The levels of phosphorylated enzyme IIA(Glc) and intracellular cAMP on various carbon sources were proportional to the expression levels of sdhC-lacZ. Disruption of crp or cya completely abolished the glucose repression of sdhC-lacZ expression. Together with data showing correlation between the intracellular cAMP concentrations and the sdhC-lacZ expression levels in several mutants and wild type, in vitro transcription assays suggest that the decrease in the CRP·cAMP level in the presence of glucose is the major determinant of the glucose repression of the sdhCDAB operon

Establishment of an experimental model of ovalbumin-induced atopic dermatitis in canines

IntroductionA reliable standard model is required to evaluate the efficacy of new drugs for companion animals, especially dogs. Canine atopic dermatitis (cAD), also known as allergic inflammatory skin disease, is a common condition. Currently, the house dust mite animal model is used in the research of cAD; however, this model exhibits significant individual variation and is difficult to standardize. In this study, we used ovalbumin as an antigen to sensitize and stimulate dogs, thereby establishing a stable model mimicking the T-helper 2 (Th2) response seen in cAD. Our objective was to create a cAD model that could be employed to evaluate the efficacy of novel drugs and mimic the Th2 dominant allergic response observed in the pathogenesis of atopic dermatitis of dogs.MethodsIn this study, six beagles were used. Normal saline was applied to two animals, and ovalbumin to four, on their dorsal skin.ResultsThe ovalbumin-treated groups exhibited clinical cAD symptoms, such as pruritus and erythema. Moreover, plasma levels of the cAD markers immunoglobulin E and CCL17 chemokine were higher in the ovalbumin-treated group than in the vehicle control group. The skin thickness of the epidermis was significantly increased in the ovalbumin-treated group, with infiltration of inflammatory cells observed in the thickened dermis region. In conclusion, treatment of canine skin with an optimal concentration of ovalbumin induced typical cAD-like symptoms, and histological and molecular analyses confirmed an enhanced Th2-related immune response.ConclusionTherefore, we successfully established a suitable Th2-dominant response mimicking cAD, which will facilitate targeted research of atopic dermatitis in dogs

KIOM-79 Prevents Lens Epithelial Cell Apoptosis and Lens Opacification in Zucker Diabetic Fatty Rats

Damage of lens epithelial cells (LECs) has been implicated in cataract formation. The aim of this study was to investigate the protective effect of KIOM-79, a combination of four plant extracts, on LECs. We examined the levels of advanced glycation end products (AGEs), nuclear factor-kappaB (NF-κB) activation and inducible nitric oxide synthase (iNOS) expression in LECs during cataract development using the Zucker diabetic fatty (ZDF) rat, an animal model of type 2 diabetes. KIOM-79 was orally administered by gavage to ZDF rats once a day for 13 weeks. Apoptosis was detected by TUNEL assay, and NF-κB activation and iNOS expression were studied by southwestern histochemistry and immunohistochemistry, respectively. In diabetic cataractous lenses, TUNEL-positive LECs were markedly increased 20-fold, and AGEs were highly accumulated (2.7-fold) in LECs. In addition, both NF-κB activation, and iNOS expression were significantly enhanced 3- to 5-fold, respectively, compared to levels found in normal ZL rats. However, the administration of KIOM-79 delayed the development of diabetic cataracts and prevented LEC apoptosis (70%) through the inhibition of AGEs, NF-κB-activation and iNOS expression. These observations suggest that KIOM-79 is useful in inhibiting diabetic cataractogenesis and acts through an antiapoptotic mechanism to protect LECs from injury

Combination of Medicinal Herbs KIOM-79 Reduces Advanced Glycation End Product Accumulation and the Expression of Inflammatory Factors in the Aorta of Zucker Diabetic Fatty Rats

Previous studies have reported that KIOM-79 shows a strong inhibitory effect on AGE formation and inhibited a proinflammatory state in a murine macrophage cell line. In the present study, we investigated the effect of KIOM-79 on AGE accumulation and vascular inflammation in the aorta of Zucker diabetic fatty (ZDF) rats, a commonly used model of type 2 diabetes. Seven-week-old male ZDF rats were treated with KIOM-79 (50 mg/kg) once a day orally for 13 weeks. We examined the dissected aortas for AGE accumulation, expression of the receptor for AGEs (RAGE), and the expression of proinflammatory factors, including monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor (VEGF), and vascular adhesion molecule-1 (VCAM-1). Nuclear factor-kappaB (NF-κB) and inducible nitric oxide synthase (iNOS) were also measured by Southwestern histochemistry, electrophoretic mobility shift assay (EMSA), and immunohistochemistry, respectively. KIOM-79 markedly reduced the accumulation of AGEs and the expression of RAGE in the aorta. We also found that KIOM-79 attenuated the expression of inflammatory factors including NF-κB, MCP-1, VEGF, VCAM-1, and iNOS in the aortas of ZDF rats. These data suggest that KIOM-79 may prevent or retard the development of inflammation in diabetic vascular disease

Evaluation of an immunochromatographic assay for the detection of anti-hepatitis A virus IgM

<p>Abstract</p> <p>Background</p> <p>Hepatitis A virus (HAV) is a causative agent of acute hepatitis, which is transmitted by person-to-person contact and via the faecal-oral route. Acute HAV infection is usually confirmed by anti-HAV IgM detection. In order to detect anti-HAV IgM in the serum of patients infected with HAV, we developed a rapid assay based on immunochromatography (ICA) and evaluated the sensitivity of this assay by comparing it with a commercial microparticle enzyme immunoassay (MEIA) that is widely used for serological diagnosis.</p> <p>Results</p> <p>The newly developed ICA showed 100% sensitivity and specificity when used to test 150 anti-HAV IgM-positive sera collected from infected patients and 75 negative sera from healthy subjects. Also, the sensitivity of ICA is about 10 times higher than MEIA used in this study by determining end point to detect independent on infected genotype of HAV. In addition, the ICA was able to detect 1 positive sample from among 50 sera from acute hepatitis patients that had tested negative for anti-HAV IgM using the MEIA.</p> <p>Conclusion</p> <p>Conclusively, ICA for the detection of anti-HAV IgM will be very effective for rapid assay to apply clinical diagnosis and epidemiological investigation on epidemics due to the simplicity, rapidity and specificity.</p