We present experimental studies on ion acceleration using an 800-nm circularly polarized laser pulse with a peak intensity of 6.9×10^{19} W/cm^{2} interacting with an overdense plasma that is ...produced by a laser prepulse ionizing an initially ultrathin plastic foil. The proton spectra exhibit spectral peaks at energies up to 9 MeV with energy spreads of 30% and fluxes as high as 3×10^{12} protons/MeV/sr. Two-dimensional particle-in-cell simulations reveal that collisionless shocks are efficiently launched by circularly polarized lasers in exploded plasmas, resulting in the acceleration of quasimonoenergetic proton beams. Furthermore, this scheme predicts the generation of quasimonoenergetic proton beams with peak energies of approximately 150 MeV using current laser technology, representing a significant step toward applications such as proton therapy.
Metastable structural polymorphs can have superior properties and applications to their thermodynamically stable phases, but the rational synthesis of metastable phases is a challenge. Here, a new ...strategy for stabilizing metastable phases using surface functionalization is demonstrated using the example of formamidinium lead iodide (FAPbI3) perovskite, which is metastable at room temperature (RT) but holds great promises in solar and light-emitting applications. We show that, through surface ligand functionalization during direct solution growth at RT, pure FAPbI3 in the cubic perovskite phase can be stabilized in nanostructures and thin films at RT without cation or anion alloying. Surface characterizations reveal that long-chain alkyl or aromatic ammonium (LA) cations bind to the surface of perovskite structure. Calculations show that such functionalization reduces the surface energy and plays a dominant role in stabilizing the metastable perovskite phase. Excellent photophysics and optically pumped lasing from the stabilized single-crystal FAPbI3 nanoplates with low thresholds were demonstrated. High-performance solar cells can be fabricated with such directly synthesized stabilized phase-pure FAPbI3 with a lower bandgap. Our results offer new insights on the surface chemistry of perovskite materials and provide a new strategy for stabilizing metastable perovskites and metastable polymorphs of solid materials in general.
Liver kinase B1 (LKB1) is mutationally inactivated in Peutz-Jeghers syndrome and in a variety of cancers including human papillomavirus (HPV)-caused cervical cancer. However, the significance of LKB1 ...mutations in cervical cancer initiation and progress has not been examined. Herein, we demonstrated that, in mouse embryonic fibroblasts, loss of LKB1 and transduction of HPV16 E6/E7 had an additive effect on constraining cell senescence while promoting cell proliferation and increasing glucose consumption, lactate production and ATP generation. Knockdown of LKB1 increased and ectopic expression of LKB1 decreased glycolysis, anchorage-independent cell growth, and cell migration and invasion in HPV-transformed cells. In the tumorigenesis and lung metastasis model in syngeneic mice, depletion of LKB1 markedly increased tumor metastatic colonies in lungs without affecting subcutaneous tumor growth. We showed that HPV16 E6/E7 enhanced the expression of hexokinase-ll (HK-II) in the glycolytic pathway through elevated c-MYC. Ectopic LKB1 reduced HK-II along with glycolysis. The inverse relationship between HK-II and LKB1 was also observed in normal and HPV-associated cervical lesions. We propose that LKB1 acts as a safeguard against HPV-stimulated aerobic glycolysis and tumor progression. These findings may eventually aid in the development of therapeutic strategy for HPV-associated malignancies by targeting cell metabolism.
Magnetic field effects have been a successful tool for studying carrier dynamics in organic semiconductors as the weak spin-orbit coupling in these materials gives rise to long spin relaxation times. ...As the spin-orbit coupling is strong in organic-inorganic hybrid perovskites, which are promising materials for photovoltaic and light-emitting applications, magnetic field effects are expected to be negligible in these optoelectronic devices. We measured significant magneto-photocurrent, magneto-electroluminescence and magneto-photoluminescence responses in hybrid perovskite devices and thin films, where the amplitude and shape are correlated to each other through the electron-hole lifetime, which depends on the perovskite film morphology. We attribute these responses to magnetic-field-induced spin-mixing of the photogenerated electron-hole pairs with different g-factors--the Δg model. We validate this model by measuring large Δg (~ 0.65) using field-induced circularly polarized photoluminescence, and electron-hole pair lifetime using picosecond pump-probe spectroscopy.
Summary
From 2014 to 2015, four novel highly pathogenic PRRS virus (HP‐PRRSV) strains named 14LY01‐FJ, 14LY02‐FJ 15LY01‐FJ, and 15LY02‐FJ were isolated from high morbidity (100%) and mortality ...(40%–80%) in piglets and sows in Fujian Province. To further our knowledge about these novel virus strains, we characterized their complete genomes and determined their pathogenicity in piglets. Full‐length genome sequencing analysis showed that these four isolates were closely related to type 2 (North American type, NA‐type) isolates, with 88.1%–96.3% nucleotide similarity, but only 60.6%–60.8% homology to the Lelystad virus (LV) (European type, EU‐type). The full length of the four isolates was determined to be 15017 or 15018 nucleotides (nt), excluding the poly(A) tail. Furthermore, the four isolates had three discontinuous deletions (aa 322–432, aa 483, and aa 504–522) within hypervariable region II (HV‐II) of Nsp2, as compared to the reference strain VR‐2332. This deletion pattern in the four isolates is consistent with strain MN184 and strain NADC30 isolated from America. Phylogenetic and molecular evolutionary analyses indicated that these virulent strains originated from a natural recombination event between the JXA1‐like HP‐PRRSV (JXA‐1 is one of the earliest Chinese HP‐PRRSV strains; sublineage 8.7) and the NADC30‐like (lineage 1) PRRSV. Animal experiments demonstrated that these four strains caused significant weight loss and severe histopathological lung lesions as compared to the negative control group. High mortality rate (40% or 80%) was found in piglets infected with any one of the four strains, similar to that found with other Chinese HP‐PRRSV strains. This study showed that the novel variant PRRSV was HP‐PRRSV, and it is therefore critical to monitor PRRSV evolution in China and develop a method for controlling PRRS.
Objectives
To evaluate the effect of peri-prostatic adipose tissue (PPAT) measurements using preoperative MRI on the prediction of prostate cancer (PCa) aggressiveness in men undergoing radical ...prostatectomy (RP).
Methods
We performed a retrospective study on 179 consecutive patients receiving RP from June 2016 to October 2018. Clinical characteristics were collected. PPAT measurements including peri-prostatic fat area (PPFA) and peri-prostatic fat area to prostate area (PA) ratio (PPFA/PA) were calculated by MRI. Multivariable logistic regression analysis was performed to identify independent predictors of PCa lymph node metastasis (LNM). The predictive performance was estimated through ROC curves. Nomograms were created based on the predictors.
Results
Pathologic Gleason score positively correlated with digital rectal examination (DRE), PSA, PPFA/PA, P504S, and Ki-67 (all
P
< 0.05). ROC curves revealed that high PPFA and high PPFA/PA were associated with LNM (both
P
< 0.05). Multivariate analysis revealed that high PPFA/PA, pathologic Gleason score, pT stage, and Ki-67 were independently predictive of LNM. The nomograms were created and the C-index was 0.945.
Conclusions
PPFA/PA is an independent predictor for LNM along with Gleason score, pT stage, and Ki-67. PPFA/PA may help predict LNM in men undergoing RP, thus providing adjunctive information for therapeutic strategy and prognosis.
To investigate the association between air pollution and upper respiratory tract infection (URTI) in children aged 0–14 years in Hefei, China in 2014–2015.
An ecological method (i.e. generalised ...additive model GAM) was used to explore the effects of air pollutants on paediatric hospital outpatients with URTI.
GAM was used to evaluate the lag effects (including lag0 to lag6, lag01 and lag06) between daily changes in particulate matter (PM10), fine particulate matter (PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3) and carbon monoxide (CO) and the number of hospital outpatients with URTI in 2014–2015, after controlling for the confounding effects of long-term trends, seasonality, day of the week, public holidays and meteorological factors.
PM10, PM2.5, SO2, NO2 and CO in the single-pollutant models had significant positive effects on the number of paediatric hospital outpatients with URTI. It was found that per 10 μg/m3 increasing in concentrations of PM10 at lag3, PM2.5, SO2, NO2 and CO at lag06 were associated with an increase of Excess risk (ER) with 0.15% (95% CI: 0.07%∼0.23%), 0.38% (95% CI: 0.17%∼0.60%), 2.92% (95% CI: 1.88%∼3.97%), 4.47% (95% CI: 3.69%∼5.25%) and 0.05% (95% CI: 0.02%∼0.08%), respectively. Only NO2 remained significantly positively associated with the number of hospital outpatients with URTI in the full-pollutant models, and ERs were 4.72% (95% CI = 3.76%–5.69%) and 4.70% (95% CI = 3.76%–5.65%) per 10 μg/m3 increase in NO2 in Model 1 (including PM10, SO2, NO2, O3 and CO) and Model 2 (including PM2.5, SO2, NO2, O3 and CO), respectively.
This study showed that short-term exposure to air pollution was associated with increased risk of URTI among paediatric hospital outpatients aged 0–14 years in Hefei. NO2 was the major air pollutant affecting the daily number of paediatric hospital outpatients with URTI.
•Generalised additive model was used to explore effects of air pollutants on child upper respiratory tract infection (URTI) outpatients.•Air pollution is associated with increased risk of child URTI outpatients.•The study addressed a gap by evaluating lag effects of air pollutants on outpatients.•NO2 was the major air pollutant affecting child URTI outpatients in the study.
We investigate theoretically the Landau levels (LLs) and magneto-transport properties of phosphorene under a perpendicular magnetic field within the framework of the effective k·p Hamiltonian and ...tight-binding (TB) model. At low field regime, we find that the LLs linearly depend both on the LL index n and magnetic field B, which is similar with that of conventional semiconductor two-dimensional electron gas. The Landau splittings of conduction and valence band are different and the wavefunctions corresponding to the LLs are strongly anisotropic due to the different anisotropic effective masses. An analytical expression for the LLs in low energy regime is obtained via solving the decoupled Hamiltonian, which agrees well with the numerical calculations. At high magnetic regime, a self-similar Hofstadter butterfly (HB) spectrum is obtained by using the TB model. The HB spectrum is consistent with the LL fan calculated from the effective k·p theory in a wide regime of magnetic fields. We find the LLs of phosphorene nanoribbon depend strongly on the ribbon orientation due to the anisotropic hopping parameters. The Hall and the longitudinal conductances (resistances) clearly reveal the structure of LLs.
•Projectile impact resistance of armor steel/ceramic/UHPC composite target was studies.•JC model parameters for 10CrNi3MoV21A armor steel were experimentally calibrated.•The calibrated parameters ...were validated with ALE algorithm adopting for projectile.•High-resistance and lightweight composite target was verified for protective structure.
The layered composite structures with high-hardness and light-weight have potential applications in the protective structures under intensive loadings, and this paper aims to examine the impact resistance of the steel/ceramic/concrete composite target against the high-speed projectile. Firstly, 14 shots of 30 mm-caliber ogive-nosed 30CrMnSiNi2A steel projectiles penetration test on seven target configurations including normal strength concrete (NSC), ultra-high performance concrete (UHPC), 10CrNi3MoV21A armor steel/UHPC, SiC ceramic/UHPC and 10CrNi3MoV21A armor steel/SiC ceramic/UHPC composite targets were conducted, and the impact resistance and ballistic efficiency factors of the composite targets were assessed quantitatively. Then, by performing the systematic static and dynamic mechanical tests, the detailed Johnson-Cook constitutive model parameters for 10CrNi3MoV21A armor steel were calibrated comprehensively. Furthermore, based on the commercial finite element program LS-DYNA, the two-dimensional (2D) axisymmetric numerical simulation with the 1 point integration single-material Arbitrary Lagrange Euler (ALE) algorithm applied to the projectile was carried out. Finally, based on the validated numerical algorithm as well as the constitutive models and the corresponding model parameters, the energy evolutions of both the projectiles and targets during the penetration process were further discussed. The SiC ceramic and the armor steel/ceramic/UHPC composite structure were verified to be the promising protective material and target configuration with distinguished ballistic performance.
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