144 research outputs found
Direct observation of split-mode exciton-polaritons in a single MoS nanotube
A single nanotube synthesized from a transition metal dichalcogenide (TMDC)
exhibits strong exciton resonances and, in addition, can support optical
whispering gallery modes. This combination is promising for observing
exciton-polaritons without an external cavity. However, traditional
energy-momentum-resolved detection methods are unsuitable for this tiny object.
Instead, we propose to use split optical modes in a twisted nanotube with the
flattened cross-section, where a gradually decreasing gap between the opposite
walls leads to a change in mode energy, similar to the effect of the barrier
width on the eigenenergies in the double-well potential. Using
micro-reflectance spectroscopy, we investigated the rich pattern of polariton
branches in single MoS tubes with both variable and constant gaps. Observed
Rabi splitting in the 40 - 60 meV range is comparable to that for a MoS
monolayer in a microcavity. Our results, based on the polariton dispersion
measurements and polariton dynamics analysis, present a single TMDC nanotube as
a perfect polaritonic structure for nanophotonics
Cl Anion-Dependent Mg-ATPase
We studied, in the rat brain, the synaptosomal and microsomal membrane fractions of Clâ ion-activated, Mg2+-dependent ATPase, satisfying the necessary kinetic peculiarities of transport ATPases, by a novel method of kinetic analysis of the multisite enzyme systems: (1) the [Mg-ATP] complex constitutes the substrate of the enzymic reaction; (2) the VÂ =Â f(Clâ) dependence-reflecting curve is bell-shaped; (3) substrate dependence, VÂ =Â f(S), curves at a constant concentration of free ligands (Mgf, ATPf, Clâ); (4) as known from the literature, in the process of reaction a phosphorylated intermediate is formed (Gerencser, Crit Rev Biochem Mol Biol 31:303â337, 1996). We report on the Cl-ATPase molecular mechanism and its place in the âP-type ATPaseâ classification
Cyclooxygenase-2 overexpression is common in serrated and non-serrated colorectal adenoma, but uncommon in hyperplastic polyp and sessile serrated polyp/adenoma
<p>Abstract</p> <p>Background</p> <p>Cyclooxygenase-2 (COX-2, <it>PTGS2</it>) plays an important role in colorectal carcinogenesis. COX-2 overexpression in colorectal cancer is inversely associated with microsatellite instability (MSI) and the CpG island methylator phenotype (CIMP). Evidence suggests that MSI/CIMP+ colorectal cancer may arise through the serrated tumorigenic pathway through various forms of serrated neoplasias. Therefore, we hypothesized that COX-2 may play a less important role in the serrated pathway.</p> <p>Methods</p> <p>By immunohistochemistry, we assessed COX-2 expression in 24 hyperplastic polyps, 7 sessile serrated polyp/adenomas (SSA), 5 mixed polyps with SSA and adenoma, 27 traditional serrated adenomas, 515 non-serrated adenomas (tubular adenoma, tubulovillous adenoma and villous adenoma), 33 adenomas with intramucosal carcinomas, 96 adenocarcinomas with serration (corkscrew gland) and 111 adenocarcinomas without serration.</p> <p>Results</p> <p>Strong (2+) COX-2 overexpression was more common in non-serrated adenomas (28% = 143/515) than in hyperplastic polyps (4.2% = 1/24, p = 0.008) and serrated polyps (7 SSAs and 5 mixed polyps) (0% = 0/12, p = 0.04). Furthermore, any (1+/2+) COX-2 overexpression was more frequent in non-serrated adenomas (60% = 307/515) than in hyperplastic polyps (13% = 3/24, p < 0.0001) and serrated polyps (SSAs and mixed polyps) (25% = 3/12, p = 0.03). Traditional serrated adenomas and non-serrated adenomas showed similar frequencies of COX-2 overexpression. Regardless of serration, COX-2 overexpression was frequent (~85%) in colorectal adenocarcinomas. Tumor location was not significantly correlated with COX-2 overexpression, although there was a trend towards higher frequencies of COX-2 overexpression in distal tumors (than proximal tumors) among hyperplastic polyps, SSAs, mixed polyps, traditional serrated adenomas and adenocarcinomas.</p> <p>Conclusion</p> <p>COX-2 overexpression is infrequent in hyperplastic polyp, SSA and mixed polyp with SSA and adenoma, compared to non-serrated and serrated adenoma. COX-2 overexpression becomes more frequent as tumors progress to higher grade neoplasias. Our observations suggest that COX-2 may play a less significant role in the serrated pathway of tumorigenesis; however, COX-2 may still play a role in later stage of the serrated pathway.</p
Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing (Nature Genetics, (2020), 52, 3, (331-341), 10.1038/s41588-019-0576-7)
Correction to: Nature Genetics, published online 05 February 2020. In the published version of this paper, the members of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium were listed in the Supplementary Information; however, these members should have been included in the main paper. The original Article has been corrected to include the members and affiliations of the PCAWG Consortium in the main paper; the corrections have been made to the HTML version of the Article but not the PDF version. Additional corrections to affiliations have been made to the PDF and HTML versions of the original Article for consistency of information between the PCAWG list and the main paper
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