Large eddy simulation on the unsteady aerodynamic response of a road vehicle in transient crosswinds

A large eddy simulation method based on a fully unstructured finite volume method was developed, and the unsteady aerodynamic response of a road vehicle subjected to transient crosswinds was investigated. First, the method was validated for a 1/20-scale wind-tunnel model in a static aerodynamic condition; this showed that the surface pressure distributions as well as the aerodynamic forces and moments were in good agreement with wind-tunnel data. Second, the method was applied to two transient crosswind situations: a sinusoidal perturbation representing the typical length scale of atmospheric turbulence and a stepwise crosswind velocity corresponding to wind gusts. Typical transient responses of the aerodynamic forces and moments such as phase shifting and undershooting or overshooting were observed, and their dependence on the frequency and amplitude of the input perturbation is discussed. Thus, the utility and validity of the large eddy simulation was demonstrated in the context that such transient aerodynamic forces are difficult to measure using a conventional wind tunnel.     

Highly enantioselective phase-transfer catalytic alkylation in the preparation of non-natural alpha-amino acids via solid phase synthesis using aldimine linker

A new Merrifield-resin-derived glycinimine tert-butyl ester (9) was prepared and applied to the enantioselective synthesis of non-natural alpha-amino acids. High enantioselectivities (86 to >99% ee) were accomplished by employing the aldimine linker under phase-transfer alkylation conditions, using 50% aqueous CsOH in toluene/chloroform (7:3) at 0 degrees C in the presence of N-(9-anthracenylmethyl)-O(9)-allylcinchonidium bromide (10 mol %).     

Raman study of the variation in anatase structure of TiO<Subscript>2</Subscript> nanopowders due to the changes of sol–gel synthesis conditions

TiO₂ nanopowders were produced by sol–gel technique under different synthesis conditions. XRD results have shown that obtained nanopowders are in anatase phase, with the presence of a small amount of highly disordered brookite phase, whereas nanocrystallite size and amount of brookite slightly depend on sol–gel synthesis conditions. Raman measurements confirm these results. The analyses of the shift and width of the most intensive anatase E _g Raman mode by phonon confinement model suggest that anatase crystallite size should be in the range between 11 and 15 nm, what is in excellent correlation with XRD results. Obtained results have shown that Raman spectroscopy is a highly sensitive method for the estimation of anatase crystallite size as well as brookite content in TiO₂ nanopowders synthesized by variable sol–gel synthesis conditions.     

Electrochemically oriented immobilization of antibody on poly-(2-cyano-ethylpyrrole)-coated gold electrode using a cyclic voltammetry

Using quartz crystal microbalance (QCM) as an immunosensor, this work investigates the contribution of a cyclic voltammetry (CV) on the proper immobilization of antibodies with the aim of enhancing its target recognition and binding ability. Primarily, CV in the range of −0.1 to 0.9 V was applied to form a layer of poly-(2-cyano-ethylpyrrole) (PCEPy) on gold quartz crystal electrode. Then the efficiencies of antibodies (anti-IgG, AIgG) immobilized electrochemically with CV applied in 0-0.65 V were compared to those immobilized via physical adsorption, by observing relative affinity towards AIgG-Fab and AIgG-Fc fragments. The results showed antibody-AIgG-Fab interaction could be enhanced about 4 times when CV is applied (11.2 ± 1.3 vs 41.6 ± 3.4 relative fluorescence unit). On the contrary, physisorbed antibodies showed a higher degree of affinity towards AIgG-Fc indicating inappropriate orientations of physisorbed antibodies. AIgG immobilized PCEPy-gold QC electrode was characterized further for its sensitivity towards a new target bovine albumin with both a QCM and fluorescence measurement. Such electrode exhibited a good sensitivity as well as a large linear dynamic range, from 0.4 μg/ml to 1.0 μg/ml and from 0.5 μg/ml to 10.0 μg/ml, at QCM and fluorescence measurement, respectively.     

Induction of Nanog in neural progenitor cells for adaptive regeneration of ischemic brain

NANOG plays a key role in cellular plasticity and the acquisition of the stem cell state during reprogramming, but its role in the regenerative process remains unclear. Here, we show that the induction of NANOG in neuronal cells is necessary for the physiological initiation of neuronal regeneration in response to ischemic stress. Specifically, we found that NANOG was preferentially expressed in undifferentiated neuronal cells, and forced expression of Nanog in neural progenitor cells (NPCs) promoted their self-renewing expansion both in ex-vivo slice cultures and in vitro limiting dilution analysis. Notably, the upstream region of the Nanog gene contains sequence motifs for hypoxia-inducible factor-1 alpha (HIF-1α). Therefore, cerebral neurons exposed to hypoxia significantly upregulated NANOG expression selectively in primitive (CD133⁺) cells, but not in mature cells, leading to the expansion of NPCs. Notably, up to 80% of the neuronal expansion induced by hypoxia was attributed to NANOG-expressing neuronal cells, whereas knockdown during hypoxia abolished this expansion and was accompanied by the downregulation of other pluripotency-related genes. Moreover, the number of NANOG-expressing neuronal cells were transiently increased in response to ischemic insult, predominantly in the infarct area of brain regions undergoing neurogenesis, but not in non-neurogenic loci. Together, these findings reveal a functional effect of NANOG-induction for the initiation of adaptive neuronal regeneration among heterogeneous NPC subsets, pointing to cellular plasticity as a potential link between regeneration and reprogramming processes.Subject terms: Stem-cell research, Experimental models of disease     

Photogenerated polyelectrolyte bilayers from an aqueous-processible photoresist for multicomponent protein patterning

A novel photoresist (PR) that can be processed under mild aqueous conditions was synthesized and used to create photogenerated polyelectrolyte bilayers. Thin films of the PR cast on polycation-coated substrates were exposed to UV irradiation to generate carboxylate groups in the photoresist. The bulk of the UV-exposed PR film was dissolved by rinsing with pH 7.4 phosphate-buffered saline, but a polyelectrolyte bilayer formed in situ at the PR/polycation interface on exposure remained bound to the substrate. The UV-exposed photoresist also exhibited pH-dependent solubility; it was soluble in water above pH 6.6, but insoluble at lower pHs. Using these unique properties, two-component protein patterning was achieved using biotinylated PR films under conditions that avoid exposing the proteins to conditions outside the narrow range of physiological pH, ionic strength, and temperature where their stability is greatest.     

Aspect ratio effects on natural convection in a water-saturated porous cavity near its density maximum

In this study, two-dimensional steady-state solutions of buoyancy-driven convection in a water-saturated porous cavity is conducted numerically for a range of different aspect ratios. The left vertical wall is considered into a partially heating location. The Brinkman–Forchheimer extended Darcy model is used to investigate the average heat transfer rate. The governing equations are solved using a finite volume method. The results obtained for various values of parameters are presented graphically in the form of streamlines, isotherms and velocity at mid-plane of the cavity. In addition, numerical results for the average Nusselt number are presented for various parametric conditions.     

Identification of protoberberine alkaloids as novel histone methyltransferase G9a inhibitors by structure-based virtual screening

The protein lysine methyltransferase G9a, which controls gene expression by epigenetic regulation of H3K9 methylation, is related to various human diseases, including cancer, drug addiction, and mental retardation. In recent years, genetic, biological, and physiological evidence has established G9a inhibitors as potential chemotherapeutic agents for cancer treatment. In this study, we identified protoberberine alkaloid pseudodehydrocorydaline (CT13) as a novel G9a inhibitor, by structure-based virtual screening of in-house library containing natural product compounds. The activity of CT13 was determined by biophysical analyses involving MALDI-TOF mass spectrometry and western blot analysis. CT13 showed selective inhibitory activity against G9a and suppressed the level of H3K9me2 in MCF7 human breast cancer cells. Molecular docking analysis suggested the binding mode of CT13 which occupies the binding site of histone H3 substrate. CT13 provides a novel scaffold for further development of analogous synthetic G9a inhibitors.

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High-performance bilayered electrolyte intermediate temperature solid oxide fuel cells

The ESB/GDC bilayer electrolyte concept has been proved to improve open circuit voltage and reduce the effective area specific resistance of SOFCs utilizing a conventional single-layer GDC electrolyte. However, high performance from such bilayer cells had not yet been demonstrated. The main obstacles toward this end have been fabrication of anode-supported thin-film electrolytes and the reactivity of ESB with conventional cathodes. Recently, an ESB-compatible low area specific resistance cathode was developed: microstructurally optimized Bi₂Ru₂O₇-ESB composites. In addition, we recently developed a novel anode functional layer which can significantly enhance the performance of SOFC utilizing GDC electrolytes. This study combines these recent achievements in SOFC studies and shows that exceptionally high performance of SOFC is possible using ESB/GDC bilayer electrolytes and Bi₂Ru₂O₇-ESB composite cathodes. The result confirms that the bilayer electrolyte and the Bi₂Ru₂O₇-ESB cathode can increase the open circuit potential and reduce the total area specific resistance. The maximum power density of the bilayered SOFC was improved to 1.95 W cm^?2 with 0.079 Ω cm² total cell area specific resistance at 650 °C. This is the highest power yet achieved in the IT range and we believe redefines the expectation level for maximum power under IT-SOFC operating conditions.     

239+240Pu concentrations of sediments and seawater in the coastal sea of Korea

Summary The ^239+240Pu content of the marine sediments and seawater of the costal sea of Korea was measured. In marine sediments the ^239+240Pu concentrations were in the range of 0.11-1.91 Bq/kg dry weight and in the coastal sea of Korea the ratio of ^239+240Pu/¹³⁷Cs was 0.27. The correlations between ^239+240Pu and ¹³⁷Cs concentrations and the content of organic matter (C, O, H, N, S) as well as the grain size of marine sediment were investigated by regression analysis. The distribution coefficient of ^239+240Pu was 1.22^. 10⁵. The ^239+240Pu concentration in seawater increased with seawater depth. However, the ¹³⁷Cs concentration in seawater did not change considerably with depth.