Transmission Properties of Subwavelength Planar Fractals for THz Wavelengths

We investigate the transmission properties of planar H fractal structures in THz range. 3D EM simulations using HFSS are used to design the parameters of the fractals and to evaluate the optical properties. We observe the transmission spectra with pass bands and stop bands, which show the subwavelength transmission through the non-metallic gaps. This unique transmission property through subwavelength apertures makes it potentially useful frequency selective components in THz region. We experimentally demonstrate its behavior by designing and fabricating four prototype planar fractals in the range of 0-1.5THz and characterize using a polarizing Fourier transform spectrometer. We find good agreement between the models and measurements

Chemistry of Advanced Materials 3(2) (2018) 36-59 Antioxidant, Anti-inflammatory and Neuroprotective Activities of a Plant Extract Derived from Traditional Chinese Medicine: SuHeXiang Wan (AT000)

International audienceIn this paper, we present SuHeXiang Wan, a medicine used in traditional Chinese medicine for the treatment of epilepsy and convulsions. We investigated the antioxidant, anti-inflammatory and neuroprotective activities of the same treatment designated as AT000. The synergy of the two plants, Dryobalanops aromatica and Saussurea lappa, of which the use in alimentary supplements is considered controversial, was evaluated for the first time. The antioxidant activity of the extract was assessed by DPPH and ORAC tests while the anti-inflammatory activity was determined by measuring the capacity of macrophages to generate a strong inflammatory response when stimulated with antigens, inducing NO release. The extract efficacy on the attenuation of the Aβ25-35-induced learning deficits (spatial working memory: spontaneous alternation in the Y-maze and contextual long-term memory: passive avoidance test) was evaluated in vivo in mice seven days after the peptide administration. The impact on lipid peroxidation in the hippocampus, an index of oxidative Chemistry of Advanced Materials (CAM) Journal homepage: http://issrpublishing.com/cam/ Iskandar et al., Chemistry of Advanced Materials 3(2) (2018) 36-59 37 stress, was also evaluated. AT000 extract showed a strong antioxidant activity at 2 mg/mL, 10 mg/mL and 301774 Trolox equivalents according to the DPPH and ORAC tests respectively. The 21-days AT000 treatment dose-dependently alleviated Aβ25-35-induced deficits, with significant prevention at the highest dose tested (250 mg/Kg/day) on the spontaneous alternation, step-through latency and escape latency parameter. 21-days AT000 treatment dose-dependently attenuated also Aβ25-35-induced increase lipid peroxidation, with a significant and complete blockade at the highest doses tested. Synergistic experiments showed that the presence of Dryobalanops aromatica and Saussurea lappa is crucial to obtain a neuroprotective effect. According to these results, AT000 could be a candidate compound in the development of therapeutic drugs for the prevention and treatment of Alzheimer's disease

The balloon-borne large-aperture submillimeter telescope for polarimetry: BLAST-Pol

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol) is a suborbital mapping experiment designed to study the role played by magnetic fields in the star formation process. BLAST-Pol is the reconstructed BLAST telescope, with the addition of linear polarization capability. Using a 1.8 m Cassegrain telescope, BLAST-Pol images the sky onto a focal plane that consists of 280 bolometric detectors in three arrays, observing simultaneously at 250, 350, and 500 um. The diffraction-limited optical system provides a resolution of 30'' at 250 um. The polarimeter consists of photolithographic polarizing grids mounted in front of each bolometer/detector array. A rotating 4 K achromatic half-wave plate provides additional polarization modulation. With its unprecedented mapping speed and resolution, BLAST-Pol will produce three-color polarization maps for a large number of molecular clouds. The instrument provides a much needed bridge in spatial coverage between larger-scale, coarse resolution surveys and narrow field of view, and high resolution observations of substructure within molecular cloud cores. The first science flight will be from McMurdo Station, Antarctica in December 2010.Comment: 14 pages, 9 figures Submitted to SPIE Astronomical Telescopes and Instrumentation Conference 201

Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus 1 region

Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 mum maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 mum with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics---including secondary filaments that often run orthogonally to the primary filament---and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core

Chemical and biological investigation of Indigofera ammoxylum (DC.) Polhill. red and white phenotypes through feature-based molecular networking

peer reviewedChemical investigation of ethyl acetate bark extracts of Indigofera ammoxylum red and white phenotypes led to the bio-guided isolation of four previously undescribed flavonoids, named (2S,3R)-3′,7-dihydroxy-4′,6-dimethoxyflavanol (1), (2S,3R)-6-methoxy-7-hydroxyflavanol (2), 2′,3′,7-trihydroxy-4′,6-dimethoxyisoflavone (7) and 2′,5'-dimethoxy-4′,5,7-trihydroxyisoflavanone (8), along with 14 known compounds (3-6 and 9-18). The previously undescribed structures were characterized based on NMR, HRESIMS, UV and IR data. Published spectroscopic data were used to deduce the structure of the known compounds. Eleven of the 18 isolated metabolites were evaluated for anti-inflammatory activity and cytotoxic activity against human liver carcinoma cells and human colon and colorectal adenocarcinoma cells. All tested compounds showed an anti-inflammatory activity (IC 50 NO < 25 μg/mL), and compounds 2 and 3 were more selective than the positive control dexamethasone. Afromorsin (6) showed promising cytotoxic properties against both cancer cell lines (IC 50 18.9 and 11.4 μg/mL). Feature-based molecular networking approach applied to bark and leaves extracts of the two phenotypes allowed to detect bioactive analogues, belonging to the families of flavones, isoflavones, flavanones, flavanols and flavonols, and to explore the chemodiversity of the species. The red and white phenotypes have a similar composition, whereas bark and leaves contain specific chemical entities. Finally, this approach highlighted a cluster of potentially bioactive and undescribed metabolites

CGG Repeat-Induced FMR1 Silencing Depends on the Expansion Size in Human iPSCs and Neurons Carrying Unmethylated Full Mutations

In fragile X syndrome (FXS), CGG repeat expansion greater than 200 triplets is believed to trigger FMR1 gene silencing and disease etiology. However, FXS siblings have been identified with more than 200 CGGs, termed unmethylated full mutation (UFM) carriers, without gene silencing and disease symptoms. Here, we show that hypomethylation of the FMR1 promoter is maintained in induced pluripotent stem cells (iPSCs) derived from two UFM individuals. However, a subset of iPSC clones with large CGG expansions carries silenced FMR1. Furthermore, we demonstrate de novo silencing upon expansion of the CGG repeat size. FMR1 does not undergo silencing during neuronal differentiation of UFM iPSCs, and expression of large unmethylated CGG repeats has phenotypic consequences resulting in&nbsp;neurodegenerative features. Our data suggest that UFM individuals do not lack the cell-intrinsic ability to silence FMR1 and that inter-individual variability in the CGG repeat size required for silencing exists in the FXS population

ESA Voyage 2050 white paper:A Polarized View of the Hot and Violent Universe

Since the birth of X-ray Astronomy, spectacular advances have been seen in the imaging, spectroscopic and timing studies of the hot and violent X-ray Universe, and further leaps forward are expected in the future. On the other hand, polarimetry is very much lagging behind: after the measurements of the Crab Nebula and Scorpius X-1, obtained by OSO-8 in the 70s, no more observations have been performed in the classical X-ray band, even if some interesting results have been obtained in hard X-rays and in soft gamma-rays. The NASA/ASI mission IXPE, scheduled for the launch in 2021, is going to provide for the first time imaging X-ray polarimetry in the 2-8 keV band thanks to its photoelectric polarimeter, coupled with ~25'' angular resolution X-ray mirrors. Its orders of magnitude improvement in sensitivity with respect to the OSO-8 Bragg polarimeter implies scientifically meaningful polarimetric measurements for at least the brightest specimens of most classes of X-ray sources. In 2027, the Chinese-led mission eXTP should also be launched. In addition to timing and spectroscopic instruments, eXTP will have on board photoelectric polarimeters very similar to those of IXPE, but with a total effective area 2-3 times larger. Building on IXPE results, eXTP will increase the number of sources for which significant polarimetric measurements could be obtained. However, further progresses, such as exploring a broader energy range, considering a larger effective area, improving the angular resolution, and performing wide-field polarization measurements, are needed to reach a mature phase for X-ray polarimetry. In the first part of this White Paper we will discuss a few scientific cases in which a next generation X-ray Polarimetry mission can provide significant advances. In the second part, a possible concept for a medium-class Next Generation X-ray Polarimetry (NGXP) mission will be sketched