1,418 research outputs found
Antenna Array Designs For Directional Wireless Communicatoin
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
Methyl 3-[(1-butyl-1H-indol-3-yl)carbonylamino]propionate
In the title molecule, C17H22N2O3, the mean plane of the terminal (C=O)OMe fragment and the indole plane form a dihedral angle of 78.94 (3)°. Intermolecular N—H⋯O hydrogen bonds link the molecules into chains extended along the c axis. The crystal packing exhibits π–π interactions, indicated by the short distance of 3.472 (2) Å between the centroids of the five-membered heterocycles of neighbouring molecules
Optimal Tracking Performance of MIMO Discrete-Time Systems with Network Parameters
The optimal regulation properties of multi-input and multioutput (MIMO) discrete-time networked control systems (NCSs), over additive white Gaussian noise (AWGN) fading channels, based on state space representation, are investigated. The average performance index is introduced. Moreover, the regulation performance is measured by the control energy and the error energy of the system, and fundamental limitations are obtained. Two kinds of network parameters, fading and the additive white Gaussian noise, are considered. The best attainable regulation performance limitations can be obtained by the limiting steady state solution of the corresponding algebraic Riccati equation (ARE). The simulation results are given to demonstrate the main results of the theoretical development
Observation of Non-Hermitian Skin Effect in Thermal Diffusion
The paradigm shift of the Hermitian systems into the non-Hermitian regime
profoundly modifies the inherent topological property, leading to various
unprecedented effects such as the non-Hermitian skin effect (NHSE). In the past
decade, the NHSE effect has been demonstrated in quantum, optical and acoustic
systems. Besides in those non-Hermitian wave systems, the NHSE in diffusive
systems has not yet been explicitly demonstrated, despite recent abundant
advances in the study of topological thermal diffusion. Here we first design a
thermal diffusion lattice based on a modified Su-Schrieffer-Heeger model which
enables the observation of diffusive NHSE. In the proposed model, the periodic
heat exchange rate among adjacent unit cells and the asymmetric temperature
field coupling inside unit cells can be judiciously realized by appropriate
configurations of structural parameters of unit cells. The transient
concentration feature of temperature field on the boundary regardless of
initial excitation conditions can be clearly observed, indicating the
occurrence of transient thermal skin effect. Nonetheless, we experimentally
demonstrated the NHSE and verified the remarkable robustness against various
defects. Our work provides a platform for exploration of non-Hermitian physics
in the diffusive systems, which has important applications in efficient heat
collection, highly sensitive thermal sensing and others.Comment: 23 pages, 5 figure
1H-Pyrrole-2-carboxylic acid
In the title compound, C5H5NO2, the pyrrole ring and its carboxyl substituent are close to coplanar, with a dihedral angle of 11.7 (3)° between the planes. In the crystal structure, adjacent molecules are linked by pairs of O—H⋯O hydrogen bonds to form inversion dimers. Additional N—H⋯O hydrogen bonds link these dimers into chains extending along the a axis
Auxin inhibits chlorophyll accumulation through ARF7-IAA14-mediated repression of chlorophyll biosynthesis genes in Arabidopsis
Auxin is a well-known important phytohormone in plant that plays vital roles in almost every development process throughout plant lifecycle. However, the effect of auxin on the metabolism of chlorophyll, one of the most important pigments involved in the photosynthesis, was intertwined and the underlying mechanism remained to be explored. Here, we found the auxin-defective yuc2 yuc6 double mutant displayed dark-green leaf color with higher chlorophyll content than wildtype, suggesting a negative regulatory role of auxin in chlorophyll biosynthesis. The chloroplast number and structure in mesophyll cells were altered and the photosynthetic efficiency was improved in yuc2 yuc6. In addition, the chlorophyll level was significantly improved during seedling de-etiolation in yuc2 yuc6 mutant, and decreased dramatically under IAA treatment, confirming the inhibitory role of auxin in chlorophyll biosynthesis. The analyses of gene expression in mature leaves and de-etiolation seedlings suggested that auxin suppressed the expression of many chlorophyll biosynthesis genes, especially PROTOCHLOROPHYLLIDE OXIDOREDUCTASE A (PORA) and GENOMES UNCOUPLED 5 (GUN5). Yeast-one-hybrid and luciferase assays demonstrated that the AUXIN RESPONSE FACTOR 2 (ARF2) and ARF7 bind to the promoter of PORA and GUN5 to suppress their expression with the help of INDOLE-3-ACETIC ACID14 (IAA14). Collectively, our research explicitly unraveled the direct inhibitory role of auxin in chlorophyll biosynthesis, and provided new insight into the interplay between auxin signaling and chlorophyll metabolism
1-Ethyl-1H,6H-pyrrolo[2,3-c]azepine-4,8(5H,7H)-dione
The title compound, C10H12N2O2, was synthesized by cyclization of 3-(1-ethylpyrrole-2-carboxamido)propanoic acid in the presence of polyphosphoric acid and diphosphorus pentoxide. In the crystal structure, adjacent molecules are linked by N—H⋯O hydrogen bonds, forming chains extending along the b axis
Establishment and characterization of immortalized human eutopic endometrial stromal cells.
PROBLEM(#br)The application of primary eutopic endometrial cells from endometriosis patients in research is restricted for short life span, dedifferentiation of hormone responsiveness.(#br)METHOD OF STUDY(#br)Human telomerase reverse transcriptase (hTERT)-induced immortalized cells (iheESCs) were infected by lentivirus. mRNA level was examined by qRT-PCR, and protein expression was quantified by Western blot. CCK-8 and EdU assay were assigned to assess the proliferation. The migration and invasion of cells were assessed by transwell assay. Clone formation assay and nude mouse tumorigenicity assay were used to evaluate colony-formation and tumorigenesis abilities.(#br)RESULTS(#br)hTERT mRNA and protein were significantly expressed higher in iheESCs compared to primary cells. iheESCs grew without morphological change for 42 passages which is much longer than 18 passages of primary cells. There was no obvious difference between primary cells and iheESCs in growth, mobility, and chromosome karyotype. Furthermore, the expression of epithelial-mesenchymal transition (EMT) markers and estrogen/progesterone receptors remained unchanged. The decidualization of iheESCs could be induced by progesterone and cAMP. Estrogen increased the proliferation and mobility of iheESCs, and lipopolysaccharides (LPS) induced the IL-1β and IL-6 promoting inflammatory response. The colony-forming ability of iheESCs, like primary cells, was lower than Ishikawa cells. In addition, tumorigenicity assay indicated that iheESCs were unable to trigger tumor formation in BALB/c nude mouse.(#br)CONCLUSIONS(#br)This study established and characterized iheESCs that kept the cellular physiology of primary cells and were not available with tumorigenic ability. Thus, iheESCs would be useful as in vitro cell model to investigate pathogenesis of endometriosis
Magnetic activities and parameters of 43 flare stars in the GWAC archive
In the archive of the Ground Wide Angle Camera (GWAC), we found 43 white
light flares from 43 stars, among which, three are sympathetic or homologous
flares, and one of them also has a quasi-periodic pulsation with a period of
minutes. Among these 43 flare stars, there are 19 new active stars
and 41 stars that have available TESS and/or K2 light curves, from which we
found 931 stellar flares. We also obtained rotational or orbital periods of 34
GWAC flare stars, of which 33 are less than 5.4 days, and ephemerides of three
eclipsing binaries from these light curves. Combining with low resolution
spectra from LAMOST and the Xinglong 2.16m telescope, we found that are in the saturation region in the rotation-activity
diagram. From the LAMOST medium-resolution spectrum, we found that Star \#3
(HAT 178-02667) has double H emissions which imply it is a binary, and
two components are both active stars. Thirteen stars have flare frequency
distributions (FFDs) from TESS and/or K2 light curves. These FFDs show that the
flares detected by GWAC can occur at a frequency of 0.5 to 9.5 yr. The
impact of flares on habitable planets was also studied based on these FFDs, and
flares from some GWAC flare stars may produce enough energetic flares to
destroy ozone layers, but none can trigger prebiotic chemistry on their
habitable planets.Comment: 20 pages, 9 figures, 3 table
- …