749 research outputs found
catena-Poly[[(1,10-phenanthroline)cobalt(II)]-di-μ-azido]
In the crystal structure of the binuclear title complex, [Co(N3)2(C12H8N2)]n, each CoII cation is coordinated by two N atoms from one chelating 1,10-phenanthroline ligand and four azide ligands in a slightly distorted octahedral coordination. The two CoII cations of the binuclear complex are related by an inversion centre and are bridged by two symmetry-related azide ligands in both μ1,1 and μ1,3 modes. The μ1,3 bridging mode gives rise to an infinite one-dimensional chain along the a axis, whereas the μ1,1 bridging mode is responsible for the formation of the binuclear CoII complex
Low Scattering Plane Wave Generator Design Using a Novel Non-coplanar Structure for Near-Field Over-the-air Testing
Resonant TMR inversion in LiF/EuS based spin-filter tunnel junctions
Resonant tunneling can lead to inverse tunnel magnetoresistance when impurity
levels rather than direct tunneling dominate the transport process. We
fabricated hybrid magnetic tunnel junctions of CoFe/LiF/EuS/Ti, with an
epitaxial LiF energy barrier joined with a polycrystalline EuS spin-filter
bar-rier. Due to the water solubility of LiF, the devices were fully packaged
in situ. The devices showed sizeable positive TMR up to 16% at low bias
voltages but clearly inverted TMR at higher bias voltages. The TMR inversion
depends sensitively on the thickness of LiF, and the tendency of inversion
disap-pears when LiF gets thick enough and recovers its intrinsic properties
MiR200-upregulated Vasohibin 2 promotes the malignant transformation of tumors by inducing epithelial-mesenchymal transition in hepatocellular carcinoma
A Signature-Based Classification of Gastric Cancer That Stratifies Tumor Immunity and Predicts Responses to PD-1 Inhibitors
Gastric cancer is a leading cause of cancer-related deaths with considerable heterogeneity among patients. Appropriate classifications are essential for prognosis prediction and individualized treatment. Although immunotherapy showed potential efficacy in a portion of patients with gastric cancer, few studies have tried to classify gastric cancer specifically based on immune signatures. In this study, we established a 3-subtype cluster with low (CLIM), medium (CMIM), and high (CHIM) enrichment of immune signatures based on immunogenomic profiling. We validated the classification in multiple independent datasets. The CHIM subtype exhibited a relatively better prognosis and showed features of “hot tumors”, including low tumor purity, high stromal components, overexpression of immune checkpoint molecules, and enriched tumor-infiltrated immune cells (activated T cells and macrophages). In addition, CHIM tumors were also characterized by frequent ARID1A mutation, rare TP53 mutation, hypermethylation status, and altered protein expression (HER2, β-catenin, Cyclin E1, PREX1, LCK, PD-L1, Transglutaminase, and cleaved Caspase 7). By Gene Set Variation Analysis, “TGFβ signaling pathway” and “GAP junction” were enriched in CLIM tumors and inversely correlated with CD8+ and CD4+ T cell infiltration. Of note, the CHIM patients showed a higher response rate to immunotherapy (44.4% vs. 11.1% and 16.7%) and a more prolonged progression-free survival (4.83 vs. 1.86 and 2.75 months) than CMIM and CLIM patients in a microsatellite-independent manner. In conclusion, the new immune signature-based subtypes have potential therapeutic and prognostic implications for gastric cancer management, especially immunotherapy
Hard superconducting gap in PbTe nanowires
Semiconductor nanowires coupled to a superconductor provide a powerful
testbed for quantum device physics such as Majorana zero modes and gate-tunable
hybrid qubits. The performance of these quantum devices heavily relies on the
quality of the induced superconducting gap. A hard gap, evident as vanishing
subgap conductance in tunneling spectroscopy, is both necessary and desired.
Previously, a hard gap has been achieved and extensively studied in III-V
semiconductor nanowires (InAs and InSb). In this study, we present the
observation of a hard superconducting gap in PbTe nanowires coupled to a
superconductor Pb. The gap size () is 1 meV (maximally 1.3 meV
in one device). Additionally, subgap Andreev bound states can also be created
and controlled through gate tuning. Tuning a device into the open regime can
reveal Andreev enhancement of the subgap conductance, suggesting a remarkable
transparent superconductor-semiconductor interface, with a transparency of
0.96. These results pave the way for diverse superconducting quantum
devices based on PbTe nanowires
Ballistic PbTe Nanowire Devices
Disorder is the primary obstacle in current Majorana nanowire experiments.
Reducing disorder or achieving ballistic transport is thus of paramount
importance. In clean and ballistic nanowire devices, quantized conductance is
expected with plateau quality serving as a benchmark for disorder assessment.
Here, we introduce ballistic PbTe nanowire devices grown using the
selective-area-growth (SAG) technique. Quantized conductance plateaus in units
of are observed at zero magnetic field. This observation represents an
advancement in diminishing disorder within SAG nanowires, as none of the
previously studied SAG nanowires (InSb or InAs) exhibit zero-field ballistic
transport. Notably, the plateau values indicate that the ubiquitous valley
degeneracy in PbTe is lifted in nanowire devices. This degeneracy lifting
addresses an additional concern in the pursuit of Majorana realization.
Moreover, these ballistic PbTe nanowires may enable the search for clean
signatures of the spin-orbit helical gap in future devices
A‐to‐I RNA editing in Klebsiella pneumoniae regulates quorum sensing and affects cell growth and virulence
Millions of adenosine (A) to inosine (I) RNA editing events are reported and well-studied in eukaryotes; however, many features and functions remain unclear in prokaryotes. By combining PacBio Sequel, Illumina whole-genome sequencing, and RNA Sequencing data of two Klebsiella pneumoniae strains with different virulence, a total of 13 RNA editing events are identified. The RNA editing event of badR is focused, which shows a significant difference in editing levels in the two K. pneumoniae strains and is predicted to be a transcription factor. A hard-coded Cys is mutated on DNA to simulate the effect of complete editing of badR. Transcriptome analysis identifies the cellular quorum sensing (QS) pathway as the most dramatic change, demonstrating the dynamic regulation of RNA editing on badR related to coordinated collective behavior. Indeed, a significant difference in autoinducer 2 activity and cell growth is detected when the cells reach the stationary phase. Additionally, the mutant strain shows significantly lower virulence than the WT strain in the Galleria mellonella infection model. Furthermore, RNA editing regulation of badR is highly conserved across K. pneumoniae strains. Overall, this work provides new insights into posttranscriptional regulation in bacteria
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