544 research outputs found
Making and identifying optical superposition of very high orbital angular momenta
We report the experimental preparation of optical superpositions of high
orbital angular momenta(OAM). Our method is based on the use of spatial light
modulator to modify the standard Laguerre-Gaussian beams to bear excessive
phase helices. We demonstrate the surprising performance of a traditional
Mach-Zehnder interferometer with one inserted Dove prism to identify these
superposed twisted lights, where the high OAM numbers as well as their possible
superpositions can be inferred directly from the interfered bright multiring
lattices. The possibility of present scheme working at photon-count level is
also shown using an electron multiplier CCD camera. Our results hold promise in
high-dimensional quantum information applications when high quanta are
beneficial.Comment: Submitted for publication consideration (4 figures
c-Jun NH2-terminal Kinase Promotes Apoptosis by Down-Regulating the Transcriptional Co-repressor CtBP
Genetic knock out of the transcriptional co-repressor carboxyl-terminal-binding protein (CtBP) in mouse embryonic fibroblasts results in up-regulation of several genes involved in apoptosis. We predicted, therefore, that a propensity toward apoptosis might be regulated through changes in cellular CtBP levels. Previously, we have identified the homeodomain-interacting protein kinase 2 as such a regulator and demonstrated that HIPK2 activation causes Ser-422 phosphorylation and degradation of CtBP. In this study, we found that c-Jun NH2-terminal kinase 1 activation triggered CtBP phosphorylation on Ser-422 and subsequent degradation, inducing p53-independent apoptosis in human lung cancer cells. JNK1 has previously been linked to UV-directed apoptosis. Expression of MKK7-JNK1 or exposure to UV irradiation reduced cellular levels of CtBP via a proteasome-mediated pathway. This effect was prevented by JNK1 deficiency. In addition, sustained activation of the JNK1 pathway by cisplatin similarly triggered CtBP degradation. These findings provide a novel target for chemotherapy in cancers lacking p53
Mesoderm Formation in Eleutherodactylus coqui: Body Patterning in a Frog with a Large Egg
AbstractThe direct developing frog, Eleutherodactylus coqui, develops from a large egg (diameter 3.5 mm). To investigate the effect of egg size on germ-layer formation, we studied mesoderm formation in E. coqui and compared it to that of Xenopus laevis (diameter 1.3 mm). First, we identified the position of prospective mesoderm in the 16-cell E. coqui embryo by cell-lineage tracing. Although the animal blastomeres are small, they form most of the blastocoel roof and make extensive contributions to some mesodermal tissues. Second, we performed recombinant analysis with X. laevis animal caps to define the distribution of mesoderm-inducing activity. Mesoderm-inducing activity in E. coqui was restricted around the marginal zone with strong activity in the superficial cells. Neither the vegetal pole nor the blastocoel floor had activity, although these same regions from X. laevis induced mesoderm. Third, we cloned Ecbra, a homologue of Xbra, an early mesoderm marker in X. laevis. Ecbra was expressed in the marginal ring close to the surface, similar to X. laevis, but E. coqui had weaker expression on the dorsal side. Our results suggest that mesoderm formation is shifted more animally and superficially in E. coqui compared to X. laevis
Alkyl substituted cucurbit[6]uril assisted competitive fluorescence recognition of lysine and methionine in aqueous solution
The use of competitive ratiometric fluorescence indicator displacement chemosensors derived from two alkyl substituted cucurbit[6]uril-based host-guest complexes is reported. In particular, the differing binding abilities of two cucurbit[6]uril derivatives towards the target analytes led to a useful ratiometric detection signal output for the discrimination of lysine and methionine versus the other tested α-amino acids in aqueous solution
A Leontief-Type Input-Output Inclusion
A Leontief-type input-output inclusion problem based on a set-valued consuming map is studied. By applying nonlinear analysis approach, in particular using the surjection and continuity technique with respect to set-valued maps, solvability
and stability results with and without continuity assumption concerning this inclusion are obtained
Synthesis of dental resins using diatomite and nano-sized SiO2 and TiO2
AbstractThe mechanical properties of dental composites were improved by porous diatomite and nano-sized silica (OX-50) used as co-fillers. The resin composites, filled with silanized OX-50 and silanized diatomite (40:60wt/wt), presented the best flexural strength (133.1MPa), elastic modulus (9.5GPa) and Vickers microhardness (104.0HV). Besides these, TiO2 nanoparticles were introduced to tune the dental resin composites colours which were valued by the CIE-Lab system. The colour parameters (L⁎, a⁎, b⁎) showed that the colour changes of resin composites could be perceived obviously, when 300–400nm TiO2 particles were introduced as fillers. The resin composite, filled with 0.5wt% TiO2, exhibited both clear discolouration (ΔE⁎=3.22) and high mechanical strength. Using scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX), the titanium elemental mapping results indicated that the TiO2 particles were distributed evenly in the prepared dental composites
Properties of Hail Storms over China and the United States from the Tropical Rainfall Measuring Mission
A 16-yr record of hail reports over the southeast US and from weather stations in China are collocated with Precipitation Features (PF) derived from the Tropical Rainfall Measurement Mission (TRMM) radar and passive microwave observations. While U.S. hail reports are dominated by cases with hail size greater than 19 mm, hail reports in China mostly include diameters of 1-10 nm and mostly occur over the Tibetan Plateau. The fraction of PFs collocated with hail reports (hail PFs) reaches 3% in the plains of the U.S. In China, the fraction is higher in high elevation regions than low elevation regions. Hail PFs in the U.S. show lower brightness temperatures, higher lightning flash rates, stronger maximum reflectivity, and higher echo tops than those in China, consistent with the larger hail diameters in the U.S. reports. The average near surface maximum reflectivity of hail PFs at higher elevations (greater than or equal to 2000 m) in China is about 5 dB smaller than those at low elevations. Larger hail is reported with PFs having stronger maximum reflectivity above 6 km, though the median of maximum reflectivity values at levels below 5 km is close among the storms with large and small hail sizes
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