We investigate the annual and local time variations of the wave‐4 structures in the plasma density and vertical drift in the low‐latitude F region by analyzing the measurements from the first ...Republic of China satellite (ROCSAT‐1) and conducting simulations with the Global Ionosphere and Plasmasphere (GIP) model. The GIP model uses apex magnetic coordinates with International Geomagnetic Reference Field (IGRF) for magnetic field, neutral wind from HWM‐07, and thermospheric parameters from the NRLMSISE‐00 model. In order to understand how the vertical drifts relate to the longitudinal structure of the topside ionosphere, we apply the equatorial vertical drifts observed from ROCSAT‐1 to drive the GIP model. The model well reproduces the longitudinal structure in electron density, and the magnitudes of electron density are comparable with ROCSAT‐1 measurement at 600 km. The ROCSAT‐1 observations of the vertical drift and plasma density show maximum amplitudes of their wave‐4 components in July–September and minimum amplitudes in December–February. An eastward shift of the wave‐4 components with increasing local time is observed in both the density and the vertical drift. The GIP model density showed similar annual and local time variations of the wave‐4 component. Since the model uses the observed equatorial vertical E × B drift as an input, the results indicate the vertical drifts are essential in the formation and evolution of the longitudinal wave‐4 density structure. The amplitude of the eastward propagating diurnal tide (DE3) at 110 km shows similar annual and local time variations as the F region parameters, supporting the link between the DE3 tide, vertical E × B drift, and F region plasma density on a global scale.
We investigated how attention to a visual feature modulates representations of other features. The feature-similarity gain model predicts a graded modulation, whereas an alternative model asserts an ...inhibitory surround in feature space. Although evidence for both types of modulations can be found, a consensus has not emerged in the literature. Here, we aimed to reconcile these different views by systematically measuring how attention modulates color perception. Based on previous literature, we also predicted that color categories would impact attentional modulation. Our results showed that both surround suppression and feature-similarity gain modulate perception of colors but they operate on different similarity scales. Furthermore, the region of the suppressive surround coincided with the color category boundary, suggesting a categorical sharpening effect. We implemented a neural population coding model to explain the observed behavioral effects, which revealed a hitherto unknown connection between neural tuning shift and surround suppression.
We present the first “weather forecast” with a coupled whole‐atmosphere/ionosphere model of Integrated Dynamics in Earth's Atmosphere (IDEA) for the January 2009 Sudden Stratospheric Warming (SSW). ...IDEA consists of the Whole Atmosphere Model and Global Ionosphere‐Plasmasphere model. A 30 day forecast is performed using the IDEA model initialized at 0000 UT on 13 January 2009, 10 days prior to the peak of the SSW. IDEA successfully predicts both the time and amplitude of the peak warming in the polar cap. This is about 2 days earlier than the National Centers for Environmental Prediction operational Global Forecast System terrestrial weather model forecast. The forecast of the semidiurnal, westward propagating, zonal wave number 2 (SW2) tide in zonal wind also shows an increase in the amplitude and a phase shift to earlier hours in the equatorial dynamo region during and after the peak warming, before recovering to their prior values about 15 days later. The SW2 amplitude and phase changes are shown to be likely due to the stratospheric ozone and/or circulation changes. The daytime upward plasma drift and total electron content in the equatorial American sector show a clear shift to earlier hours and enhancement during and after the peak warming, before returning to their prior conditions. These ionospheric responses compare well with other observational studies. Therefore, the predicted ionospheric response to the January 2009 SSW can be largely explained in simple terms of the amplitude and phase changes of the SW2 zonal wind in the equatorial E region.
Key Points
First successful forecast of SSW with the online‐coupled IDEA model
First successful forecast of ionospheric response to SSW with the IDEA model
Predicted ionospheric change corresponds well to SW2 amplitude and phase change
Resistance to cytotoxic chemotherapy drugs remains as the major cause of treatment failure in acute myeloid leukemia. Histone deacetylases (HDAC) are important regulators to maintain chromatin ...structure and control DNA damage; nevertheless, how each HDAC regulates genome stability remains unclear, especially under genome stress conditions. Here, we identified a mechanism by which HDAC3 regulates DNA damage repair and mediates resistance to chemotherapy drugs. In addition to inducing DNA damage, chemotherapy drugs trigger upregulation of HDAC3 expression in leukemia cells. Using genetic and pharmacological approaches, we show that HDAC3 contributes to chemotherapy resistance by regulating the activation of AKT, a well-documented factor in drug resistance development. HDAC3 binds to AKT and deacetylates it at the site Lys20, thereby promoting the phosphorylation of AKT. Chemotherapy drug exposure enhances the interaction between HDAC3 and AKT, resulting in decrease in AKT acetylation and increase in AKT phosphorylation. Whereas HDAC3 depletion or inhibition abrogates these responses and meanwhile sensitizes leukemia cells to chemotoxicity-induced apoptosis. Importantly, in vivo HDAC3 suppression reduces leukemia progression and sensitizes MLL-AF9
leukemia to chemotherapy. Our findings suggest that combination therapy with HDAC3 inhibitor and genotoxic agents may constitute a successful strategy for overcoming chemotherapy resistance.
The ability of solid-state 13C NMR to detect and quantify small amounts of sp2-hybridized carbon on the surface of ∼5 nm diameter nanodiamond particles is demonstrated. The CC carbon fraction is ...only 1.1 ± 0.4% in pristine purified detonation nanodiamond, while a full single-layer graphitic or “bucky diamond” shell would contain ca. 25% of all C in a 5 nm diameter particle. Instead of large aromatic patches repeatedly proposed in the recent literature, sp3-hybridized CH and COH carbons cover most of the nanodiamond particle surface, accounting for ∼5% each. CO and COO groups also seen in X-ray absorption near-edge structure spectroscopy (XANES) but not detected in previous NMR studies make up ca. 1.5% of all C. They are removed by heat treatment at 800 °C, which increases the aromatic fraction. 13C{1H} NMR demonstrates that the various sp2-hybridized carbons are mostly not protonated, but cross-polarization shows that they are separated from 1H by only a few bond lengths, which proves that they are near the protonated surface. Together, the observed C–H, C–OH, CO, and CC groups account for 12–14% of all C, which matches the surface fraction expected for bulk-terminated 5 nm diameter diamond particles.
We examine the forces that determine zonal wind structure in the low‐latitude evening thermosphere and its relation with ion‐neutral coupling. These winds drive the evening F region dynamo that ...affects the equatorial ionization anomaly (EIA) and the generation of plasma irregularities. Forces are calculated using the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model coupled with the Global Ionosphere‐Plasmasphere model. At 19 LT, the horizontal pressure gradient dominates the net acceleration of neutral winds below ∼220 km, while it tends to be offset by ion drag and viscosity higher up. The eastward pressure‐gradient acceleration above 200 km increases approximately linearly with height and tends to be similar for different latitudes and different levels of solar activity. The pressure‐gradient and ion‐drag forces in the central F region approximately balance for field lines that pass through the EIA. Viscosity is an important additional force at non‐EIA latitudes and in the bottomside and topside EIA ionosphere. An increase in E region drag on plasma convection due to increased nighttime ionization causes both the ion and neutral velocities in the F region to decrease, while the velocity difference tends to be maintained. The presence of a low‐latitude evening time vertical shear in the zonal wind is associated primarily with a strong eastward pressure‐gradient acceleration at high altitude that reverses the daytime westward wind and a weak low‐altitude pressure‐gradient acceleration of either eastward or westward direction that fails to reverse the low‐altitude westward wind present in the afternoon.
Key Points
Pressure gradient, ion drag, and viscous forces are in approximate balance at low latitudes
Ion drag approximately balances pressure gradient around EIA, supporting Rishbeth hypothesis
Evening zonal wind shear is created by strong eastward acceleration above 200 km
Previous results from our trial showed that adding oxaliplatin to radiotherapy (RT) increased survival in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) at 2 years. Here, we ...present the data of long-term efficacy and late toxic effects.
Between January 2001 and January 2003, 115 Patients with nonkeratinizing/undifferentiated locoregionally advanced NPC were randomly to receive either RT alone (n = 56) or plus concurrent oxaliplatin 70 mg/m2 weekly for six cycles (n = 59).
After a median follow-up of 114 months (range 18–139 months), the 5-year overall survival (OS) and metastasis-free survival (MFS) rates in the concurrent chemoradiotherapy (CCRT) group were significantly higher than those observed in the RT-alone group (OS, 73.2% versus 60.2%, P = 0.028; MFS, 74.7% versus 63.0%, P = 0.027). However, CCRT did not improve locoregional failure-free survival significantly. Subgroup analyses showed that the superiorities of CCRT mainly existed in the T3-4N0-1 stage subgroup (OS: HR = 0.394, P = 0.034). The grade 3/4 late toxic effects were similar in the two groups.
The long-term follow-up data confirms the role of CCRT as a treatment of locoregionally advanced NPC. Oxaliplatin can be considered as an alternative optional therapeutic regimen for these patients due to its high efficiency and low toxic effect.
miR-374a has been reported to function as an oncogene during tumor pathogenesis. In this study, miR-374a is observed to reduce nasopharyngeal carcinoma (NPC) cell proliferation, migration, invasion, ...metastasis and cisplatin (DDP) resistance in vitro and in vivo. Mechanistic analyses indicate that miR-374a directly targets CCND1 to inactivate pPI3K/pAKT/c-JUN forming a negative feedback loop, as well as suppressing downstream signals related to cell cycle progression and epithelial-mesenchymal transition (EMT). Interestingly, we also observed that miR-374a direct targeting of CCND1 is modulated by tumor suppressor PDCD4 via suppressing pPI3K/pAKT/c-JUN signaling. In clinical specimens, miR-374a was positively and negatively correlated with expression of PDCD4 and CCND1, respectively. Our studies are the first to demonstrate that the miR-374a-CCND1-pPI3K/AKT-c-JUN feedback loop induced by PDCD4 supresses NPC cell growth, metastasis and chemotherapy resistance.
The microstructure and mechanical properties of roll bonded and annealed SUS304/Q235 multilayer steels were investigated by using optical microscope (OM), scanning electron microscope (SEM), electron ...probe microanalysis (EPMA), electron backscattered diffraction (EBSD), Transmission electron microscope (TEM) and universal testing in detail. Hot rolling with high reduction ratio could strengthen the clad interface due to the interface oxides rupture, increased residual compression stress and sufficient alloy element diffusion. The hardness and tensile strength are increased, while the fracture elongation is decreased sharply with the increasing cold rolling reduction ratio. The hardened SUS304 layers are easy to strain softening, leading to localized necking, wave-like clad interface and nonuniform layer thickness during the cold rolling process. The annealed grain orientations in the separated SUS304 layers also reveal that the overall grain boundaries are across the Q235 layer, which is attributed to the grain coarsening across clad interface during the annealing process. At the grain boundaries in the SUS304 layer, the austenite-to-ferrite transition reveals the serious grain boundary diffusion behavior. Moreover, tensile fracture characteristics reveal that interface delamination cracks are inhibited by annealing treatment, which may be attributed to the sufficient alloy element diffusion at the clad interface.
We demonstrate a novel integrated silicon and ultra-low-loss Si3N4 waveguide platform. Coupling between layers is achieved with (0.4 ± 0.2) dB of loss per transition and a 20 nm 3-dB bandwidth for ...one tapered coupler design and with (0.8 ± 0.2) dB of loss per transition and a 100 nm 3-dB bandwidth for another. The minimum propagation loss measured in the ultra-low-loss waveguides is 1.2 dB/m in the 1590 nm wavelength regime.
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