Chirped imaging pulses in four-dimensional electron microscopy: femtosecond pulsed hole burning

The energy and time correlation, i.e. the chirp, of imaging electron pulses in dispersive propagation is measured by time-slicing (temporal hole burning) using photon-induced near-field electron microscopy. The chirp coefficient and the degree of correlation are obtained in addition to the duration of the electron pulse and its energy spread. Improving temporal and energy resolutions by time-slicing and energy-selection is discussed here and we explore their utility in imaging with time and energy resolutions below those of the generated ultrashort electron pulse. Potential applications for these imaging capabilities are discussed

Application of Recycled Zero-Valent Iron Nanoparticle to the Treatment of Wastewater Containing Nitrobenzene

Zero-valent iron (ZVI) was synthesized using iron oxide, a byproduct of pickling line at a steel work. ZVI with a mean particle size of 500 nm was synthesized. The reaction activity of the synthesized ZVI was much higher than commercial ZVI. When applied to the decomposition of nitrobenzene (NB), the ZVI particles underwent corrosion and passivation oxide film formation, resulting in particle size decrease. The NB decomposition rate increased with increasing ZVI dosage level and with decreasing pH. The solution pH increased monotonously with increasing reaction duration, whereas the aniline concentration showed a maximum at 50 min. Based on the GC/MS analysis, NB is presumed to be reduced into aniline via reductive intermediates such as azobenzene and azoxybenzene. When combined with a subsequent biological process, the synthesized ZVI will be able to decompose NB in wastewater effectively

Violet-light spontaneous and stimulated emission from ultrathin In-rich InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition

We investigated the spontaneous and stimulated emission properties of violet-light-emitting ultrathin In-rich InGaN/GaN multiple quantum wells (MQWs) with indium content of 60%-70%. The Stokes shift was smaller than that of In-poor InGaN MQWs, and the emission peak position at 3.196 eV was kept constant with increasing pumping power, indicating negligible quantum confined Stark effect in ultrathin In-rich InGaN MQWs despite of high indium content. Optically pumped stimulated emission performed at room temperature was observed at 3.21 eV, the high-energy side of spontaneous emission, when the pumping power density exceeds ???31 kW/ cm2.open6

Dieckol from Ecklonia cava Regulates Invasion of Human Fibrosarcoma Cells and Modulates MMP-2 and MMP-9 Expression via NF-κB Pathway

The matrix metalloproteinase (MMP) family is involved in the breakdown of extracellular matrix in normal physiological processes, as well as in the disease processes such as arthritis and cancer metastasis. In the present study, dieckol was obtained with high yield from marine brown alga Ecklonia cava (EC), and its effect was assessed on the expression of MMP-2 and -9 and morphological changes in human fibrosarcoma cell line (HT1080). Dieckol inhibited the expression of MMP-2 and -9 in a dose-dependent manner and also suppressed the cell invasion and the cytomorphology in 3D culture system on HT1080 cells. Moreover, dieckol may influence nuclear factor kappa B (NF-κB) pathway without obvious influence on activator protein-1 (AP-1) pathway and tissue inhibitor of metalloproteinases (TIMPs). In conclusion, dieckol could significantly suppress MMP-2 and -9 expression and alter cytomorphology of HT1080 cell line via NF-κB pathway

Expression analysis of diosgenin pathway genes and diosgenin accumulation in fenugreek sprouts after exposure to copper sulfate

Trigonella foenum-graecum L. is an annual herb belonging to the family Fabaceae commonly called Fenugreek. It is rich in various secondary metabolites such as alkaloids, flavonoids, phenolic compounds, and steroidal saponins. In recent years, diosgenin has much attention in the cosmetic, functional food, and pharmaceutical industries. In this study we aimed to examine the effect of different concentrations of copper sulfate (CuSO4) on growth, diosgenin biosynthetic (DB) gene expression, and diosgenin accumulation in T. foenum-graecum sprouts. Results showed that the seed germination, fresh weight, shoot length, and root length were gradually decreased with increasing the CuSO4 concentrations. In contrast, the expression level of DBGs i.e., TfSQS, TfSQLE, TfCAS, and TfSTRL were gradually upregulated with increasing the CuSO4 concentrations. Among all those tested concentrations, the expression levels of all those genes were significantly higher in 0.5 mM CuSO4 treated sprouts. The highest expression level was obtained in the TfCAS gene, which was 3.25-fold higher than the unexposed sprouts. The diosgenin content was significantly influenced in the CuSO4 exposed sprouts. The highest diosgenin content was achieved in the 5.0 mM followed by 1.0, 10.0, and 0.5 mM CuSO4 exposed concentrations, with a reduction of 41%, 39%, 36%, and 35%, respectively. From these results, it is shown that exposure of fenugreek sprout to CuSO4 is one of the suitable strategies to enhance the accumulation of diosgenin content

Influence of cytokinins and yeast extract on growth and flavone production in hairy root cultures of Scutellaria baicalensis

Hairy roots produce various bioactive chemical compounds than wild-type roots which offer a promising in vitro approach for synthesizing important nutraceutical compounds. The purpose of this study is to increase the production of flavone compounds in hairy root cultures of Scutellaria baicalensis by the addition of elicitors such as cytokinins and yeast extract. Cytokinins such as kinetin (KIN), 6-benzylaminopurine (BAP), and Thidiazuron (TDZ) were utilized at 0.1, 0.5, and 1.0 mg/L, whereas for yeast extract treatment 50, 100, and 150 mg/L concentrations were added to the ½ SH medium. Effects of elicitors were measured in terms of dry biomass and flavone contents (baicalin, baicalein, and wogonin) using high-performance liquid chromatography (HPLC). The highest dry weight was achieved in the control hairy root than that of all cytokinins-treated hairy root cultures. In all the cytokinin-treated hairy root cultures, as the concentration increased the dry weight of the hairy root decreased. In contrast, in all the yeast extract-treated hairy root cultures as the concentration increases the dry weight of the hairy root increased, whereas the highest dry weight was achieved in 150 mg/L of yeast extract. Moving to the flavone content, baicalin was detected highest content in all the hairy root cultures supplied with cytokinin and yeast extract. The highest total flavone content was achieved in the hairy root culture treated with 1.0 mg/L of TDZ and 50 mg/L of yeast extract. This result might help the commercial agronomic sector by facilitating the in vitro mass production of nutraceuticals using S. baicalensis hairy root cultures

Ordered mesoporous Co3O4 spinels as stable, bifunctional, noble metal-free oxygen electrocatalysts

We report the use of noble metal-free ordered mesoporous Co 3O4 spinels (meso-Co3O4), templated from KIT-6 mesoporous silica, as highly active and stable bifunctional electrocatalysts for both oxygen evolution and reduction reactions (OER and ORR, respectively). The meso-Co3O4 nanostructures showed high activity for OER in an alkaline medium (0.1 M KOH), which makes them comparable to the most active Ir/C catalyst and better than Co3O4 nanoparticles (NPs) and the Pt/C catalyst. Furthermore, meso-Co 3O4 exhibited enhanced stability, compared to Co 3O4 NPs. The enhanced activity and stability of meso-Co3O4 over Co3O4 NPs could be attributed to its high surface area and structural stability of the gyroid network structure in the meso-Co3O4 catalysts. The meso-Co3O4 nanostructures also showed promising activity for ORR and exhibited a methanol-tolerance superior to the Pt/C catalyst. The total overpotential of meso-Co3O4 for OER (at 10 mA cm-2) and ORR (at -3 mA cm-2) was 1.034 V, which is on a par with noble metal-based catalysts. This work demonstrates that directing metal oxides into mesostructures is a promising means of preparing highly active, stable, bifunctional oxygen electrocatalysts that can potentially replace expensive noble metal-based catalysts. This design strategy can be extended to other reactions relevant to energy conversion and storage applications.close17