Surrogate models are used to dramatically improve the design efficiency of numerical aerodynamic shape optimization, where high-fidelity, expensive computational fluid dynamics (CFD) is often ...employed. Traditionally, in adaptation, only one single sample point is chosen to update the surrogate model during each updating cycle, after the initial surrogate model is built. To enable the selection of multiple new samples at each updating cycle, a few parallel infilling strategies have been developed in recent years, in order to reduce the optimization wall clock time. In this article, an alternative parallel infilling strategy for surrogate-based constrained optimization is presented and demonstrated by the aerodynamic shape optimization of transonic wings. Different from existing methods in which multiple sample points are chosen by a single infill criterion, this article uses a combination of multiple infill criteria, with each criterion choosing a different sample point. Constrained drag minimizations of the ONERA-M6 and DLR-F4 wings are exercised to demonstrate the proposed method, including low-dimensional (6 design variables) and higher-dimensional problems (up to 48 design variables). The results show that, for surrogate-based optimization of transonic wings, the proposed method is more effective than the existing parallel infilling strategies, when the number of initial sample points are in the range from
N
v
to
8N
v
(
N
v
here denotes the number of design variables). Each case is repeated 50 times to eliminate the effect of randomness in our results.
Hot Carrier-Assisted Intrinsic Photoresponse in Graphene Gabor, Nathaniel M.; Song, Justin C. W.; Ma, Qiong ...
Science (American Association for the Advancement of Science),
11/2011, Letnik:
334, Številka:
6056
Journal Article
Recenzirano
Odprti dostop
We report on the intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation (of wavelength 850 nanometers) at the p-n ...interface leads to striking six-fold photovoltage patterns as a function of bottom-and top-gate voltages. These patterns, together with the measured spatial and density dependence of the photoresponse, provide strong evidence that nonlocal hot carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene. This regime, which features a long-lived and spatially distributed hot carrier population, may offer a path to hot carrier-assisted thermoelectric technologies for efficient solar energy harvesting.
Summary
Background
Asthma in the elderly (aged ≥ 65 years old) is a significant concern with high morbidity, but the pathophysiology remains unclear particularly in late‐onset asthma. Recent studies ...suggest staphylococcal enterotoxin IgE (SE‐IgE) sensitization to be a risk factor for asthma in general populations; however, the associations have not been examined in late‐onset elderly asthma.
Objective
We aimed to examine the associations of SE‐IgE sensitization with late‐onset asthma in the elderly, using a database of elderly asthma cohort study.
Methods
A total of 249 elderly patients with asthma and 98 controls were analysed. At baseline, patients were assessed for demographics, atopy, induced sputum profiles and comorbidities including chronic rhinosinusitis (CRS). Serum total IgE and SE‐IgE levels were measured. Asthma severity was assessed on the basis of asthma outcomes during a 12‐month follow‐up period.
Results
At baseline, serum SE‐IgE concentrations were significantly higher in patients with asthma than in controls median 0.16 (interquartile range 0.04–0.53) vs. 0.10 (0.01–0.19), P < 0.001. Elderly asthma patients with high SE‐IgE levels had specific characteristics of having more severe asthma, sputum eosinophilia and CRS, compared to those with lower SE‐IgE levels. In multivariate logistic regression analyses, the associations between serum SE‐IgE concentrations and severe asthma were significant, independently of covariables SE‐IgE‐high (≥ 0.35 kU/L) vs. negative (< 0.10 kU/L) group: odds ratio 7.47, 95% confidence interval 1.86–30.03, P = 0.005. Multiple correspondence analyses also showed that high serum SE‐IgE level had close relationships with severe asthma, CRS and sputum eosinophilia together.
Conclusions and Clinical Relevance
This is the first report on the significant associations of SE‐IgE sensitization with late‐onset asthma in the elderly, particularly severe eosinophilic asthma with CRS comorbidity. Our findings indicate a potential implication of SE in the high morbidity burden of elderly asthma and suggest clues to the pathogenesis of severe late‐onset eosinophilic asthma in the elderly.
A direct regeneration of cathode materials from spent LiFePO
4
batteries using a solid phase sintering method has been proposed in this article. The spent battery is firstly dismantled to separate ...the cathode and anode plate, and then the cathode plate is soaked in DMAC organic solvent to separate the cathode materials and Al foil at optimal conditions of 30 min at 30 °C and solid liquid ratio of 1 : 20 g ml
−1
. XRD and SEM results of the spent LiFePO
4
after separation show that there are some impurity phase components and irregular morphologies with many agglomerations. The spent materials are regenerated at appropriate temperatures with doping of new LiFePO
4
at different ratios. Battery capacities from regenerated LiFePO
4
can reach over 120 mA h g
−1
at 0.1C discharge conditions, especially with the highest value of 144 mA h g
−1
with a doping ratio of 3 : 7 at 700 °C. The rate capabilities and cycling performance of batteries made from regenerated LiFePO
4
with doping at 600 °C and 700 °C are generally better than those at 800 °C. All the performances of batteries made from regenerated LiFePO
4
with pure phase and uniform morphology can meet the basic requirements for reuse.
A direct regeneration of cathode materials from spent LiFePO
4
batteries using a solid phase sintering method has been proposed in this article.
Highlights • An increased risk of developing Alzheimer’s disease (AD) in people with diabetes. • The underlying molecular mechanisms still remain elusive. • Reviewing the current studies on common ...pathological processes of Alzheimer’s disease and diabetes. • Focusing on potential mechanisms through which diabetes affects the initiation and progression of Alzheimer’s disease.
Mesoporous SBA-15 materials were functionalized with amine groups through postsynthesis and one-pot synthesis, and the resulting functionalized materials were investigated as matrixes for controlled ...drug delivery. The materials were characterized by FTIR, N(2) adsorption/desorption analysis, zeta potential measurement, XRD, XPS, and TEM. Ibuprofen (IBU) and bovine serum albumin (BSA) were selected as model drugs and loaded onto the unmodified and functionalized SBA-15. It was revealed that the adsorption capacities and release behaviors of these model drugs were highly dependent on the different surface properties of SBA-15 materials. The release rate of IBU from SBA-15 functionalized by postsynthesis is found to be effectively controlled as compared to that from pure SBA-15 and SBA-15 functionalized by one-pot synthesis due to the ionic interaction between carboxyl groups in IBU and amine groups on the surface of SBA-15. However, SBA-15 functionalized by one-pot synthesis is found to be more favorable for the adsorption and release of BSA due to the balance of electrostatic interaction and hydrophilic interaction between BSA and the functionalized SBA-15 matrix.
Strong electron-electron interactions in graphene are expected to result in multiple-excitation generation by the absorption of a single photon. We show that the impact of carrier multiplication on ...photocurrent response is enhanced by very inefficient electron cooling, resulting in an abundance of hot carriers. The hot-carrier-mediated energy transport dominates the photoresponse and manifests itself in quantum efficiencies that can exceed unity, as well as in a characteristic dependence of the photocurrent on gate voltages. The pattern of multiple photocurrent sign changes as a function of gate voltage provides a fingerprint of hot-carrier-dominated transport and carrier multiplication.
Fluid forces control endothelial sprouting Song, Jonathan W.; Munn, Lance L.
Proceedings of the National Academy of Sciences - PNAS,
09/2011, Letnik:
108, Številka:
37
Journal Article
Recenzirano
Odprti dostop
During angiogenesis, endothelial cells (ECs) from intact blood vessels quickly infiltrate avascular regions via vascular sprouting. This process is fundamental to many normal and pathological ...processes such as wound healing and tumor growth, but its initiation and control are poorly understood. Vascular endothelial cell growth factor (VEGF) can promote vessel dilation and angiogenic sprouting, but given the complex nature of vascular morphogenesis, additional signals are likely necessary to determine, for example, which vessel segments sprout, which dilate, and which remain quiescent. Fluid forces exerted by blood and plasma are prime candidates that might codirect these processes, but it is not known whether VEGF cooperates with mechanical fluid forces to mediate angiogenesis. Using a microfluidic tissue analog of angiogenic sprouting, we found that fluid shear stress, such as exerted by flowing blood, attenuates EC sprouting in a nitric oxide-dependent manner and that interstitial flow, such as produced by extravasating plasma, directs endothelial morphogenesis and sprout formation. Furthermore, positive VEGF gradients initiated sprouting but negative gradients inhibited sprouting, promoting instead sheet-like migration analogous to vessel dilation. These results suggest that ECs integrate signals from fluid forces and local VEGF gradients to achieve such varied goals as vessel dilation and sprouting.
Chiral plasmons without magnetic field Song, Justin C. W.; Rudner, Mark S.
Proceedings of the National Academy of Sciences - PNAS,
04/2016, Letnik:
113, Številka:
17
Journal Article
Recenzirano
Odprti dostop
Plasmons, the collective oscillations of interacting electrons, possess emergent properties that dramatically alter the optical response of metals. We predict the existence of a new class of ...plasmons—chiral Berry plasmons (CBPs)—for a wide range of 2D metallic systems including gapped Dirac materials. As we show, in these materials the interplay between Berry curvature and electron–electron interactions yields chiral plasmonic modes at zero magnetic field. The CBP modes are confined to system boundaries, even in the absence of topological edge states, with chirality manifested in split energy dispersions for oppositely directed plasmon waves. We unveil a rich CBP phenomenology and propose setups for realizing them, including in anomalous Hall metals and optically pumped 2D Dirac materials. Realization of CBPs will offer a powerful paradigm for magnetic field-free, subwavelength optical nonreciprocity, in the mid-IR to terahertz range, with tunable splittings as large as tens of THz, as well as sensitive all-optical diagnostics of topological bands.
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