ROME: Robustifying Memory-Efficient NAS via Topology Disentanglement and Gradients Accumulation

Single-path based differentiable neural architecture search has great strengths for its low computational cost and memory-friendly nature. However, we surprisingly discover that it suffers from severe searching instability which has been primarily ignored, posing a potential weakness for a wider application. In this paper, we delve into its performance collapse issue and propose a new algorithm called RObustifying Memory-Efficient NAS (ROME). Specifically, 1) for consistent topology in the search and evaluation stage, we involve separate parameters to disentangle the topology from the operations of the architecture. In such a way, we can independently sample connections and operations without interference; 2) to discount sampling unfairness and variance, we enforce fair sampling for weight update and apply a gradient accumulation mechanism for architecture parameters. Extensive experiments demonstrate that our proposed method has strong performance and robustness, where it mostly achieves state-of-the-art results on a large number of standard benchmarks.Comment: Observe new collapse in memory efficient NAS and address it using ROM

Enhanced photodegradation activity of methyl orange over Z-scheme type MoO3-g-C3N4 composite under visible light irradiation

National Natural Science Foundation of China [21003109, 51108424]; Opening-foundation of State Key Laboratory Physical Chemistry and Solid Surfaces, Xiamen University, China [201311]; School of Energy Resources at University of WyomingNovel Z-scheme type MoO3-g-C3N4 composites photocatalysts were prepared with a simple mixing-calcination method, and evaluated for their photodegradation activities of methyl orange (MO). The optimized MoO3-g-C3N4 photocatalyst shows a good activity with a kinetic constant of 0.0177 min(-1), 10.4 times higher than that of g-C3N4. Controlling various factors (MoO3-g-C3N4 amount, initial MO concentration, and pH value of MO solution) can lead to the enhancement of the photocatalytic activity of the composite. Only MoO3 and g-C3N4 are detected with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra. N-2 adsorption and UV-vis diffuse reflectance spectroscopy (DRS) results suggest that the addition of MoO3 slightly affects the specific surface area and the photoabsorption performance. The transmission electron microscopy (TEM) image of MoO3-g-C3N4 indicates a close contact between MoO3 and g-C3N4, which is beneficial to interparticle electron transfer. The high photocatalytic activity of MoO3-g-C3N4 is mainly attributed to the synergetic effect of MoO3 and g-C3N4 in electron-hole pair separation via the charge migration between the two semiconductors. The charge transfer follows direct Z-scheme mechanism, which is proven by the reactive species trapping experiment and the (OH)-O-center dot-trapping photoluminescence spectra

Ultra-low-dose spectral-detector computed tomography for the accurate quantification of pulmonary nodules: an anthropomorphic chest phantom study

PURPOSETo assess the quantification accuracy of pulmonary nodules using virtual monoenergetic images (VMIs) derived from spectral-detector computed tomography (CT) under an ultra-low-dose scan protocol.METHODSA chest phantom consisting of 12 pulmonary nodules was scanned using spectral-detector CT at 100 kVp/10 mAs, 100 kVp/20 mAs, 120 kVp/10 mAs, and 120 kVp/30 mAs. Each scanning protocol was repeated three times. Each CT scan was reconstructed utilizing filtered back projection, hybrid iterative reconstruction, iterative model reconstruction (IMR), and VMIs of 40–100 keV. The signal-to-noise ratio and air noise of images, absolute differences, and absolute percentage measurement errors (APEs) of the diameter, density, and volume of the four scan protocols and ten reconstruction images were compared.RESULTSWith each fixed reconstruction image, the four scanning protocols exhibited no significant differences in APEs for diameter and density (all P > 0.05). Of the four scan protocols and ten reconstruction images, APEs for nodule volume had no significant differences (all P > 0.05). At 100 kVp/10 mAs, APEs for density using IMR were the lowest (APE-mean: 6.69), but no significant difference was detected between VMIs at 50 keV (APE-mean: 11.69) and IMR (P = 0.666). In the subgroup analysis, at 100 kVp/10 mAs, there were no significant differences between VMIs at 50 keV and IMR in diameter and density (all P > 0.05). The radiation dose at 100 kVp/10 mAs was reduced by 77.8% compared with that at 120 kVp/30 mAs.CONCLUSIONCompared with IMR, reconstruction at 100 kVp/10 mAs and 50 keV provides a more accurate quantification of pulmonary nodules, and the radiation dose is reduced by 77.8% compared with that at 120 kVp/30 mAs, demonstrating great potential for ultra-low-dose spectral-detector CT

Mechanism and Treatment Related to Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is a type of neonatal brain injury, which occurs due to lack of supply and oxygen deprivation to the brain. It is associated with a high morbidity and mortality rate. There are several therapeutic strategies that can be used to improve outcomes in patients with HIE. These include cell therapies such as marrow mesenchymal stem cells (MSCs) and umbilical cord blood stem cells (UCBCs), which are being incorporated into the new protocols for the prevention of ischemic brain damage. The focus of this review is to discuss the mechanism of oxidative stress in HIE and summarize the current available treatments for HIE. We hope that a better understanding of the relationship between oxidative stress and HIE will provide new insights on the potential therapy of this devastating condition

Pharmacokinetics/pharmacodynamics of polymyxin B in patients with bloodstream infection caused by carbapenem-resistant Klebsiella pneumoniae

Introduction: Polymyxin B is a last-line therapy for carbapenem-resistant microorganisms. However, a lack of clinical pharmacokinetic/pharmacodynamic (PK/PD) data has substantially hindered dose optimization and breakpoint setting.Methods: A prospective, multi-center clinical trial was undertaken with polymyxin B [2.5 mg/kg loading dose (3-h infusion), 1.25 mg/kg/12 h maintenance dose (2-h infusion)] for treatment of carbapenem-resistant K. pneumoniae (CRKP) bloodstream infections (BSI). Safety, clinical and microbiological efficacy were evaluated. A validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was applied to determine the concentrations of polymyxin B in blood samples. Population pharmacokinetic (PK) modeling and Monte Carlo simulations were conducted to examine the susceptibility breakpoint for polymyxin B against BSI caused by CRKP.Results: Nine patients were enrolled and evaluated for safety. Neurotoxicity (5/9), nephrotoxicity (5/9), and hyperpigmentation (1/9) were recorded. Blood cultures were negative within 3 days of commencing therapy in all 8 patients evaluated for microbiological efficacy, and clinical cure or improvement occurred in 6 of 8 patients. Cmax and Cmin following the loading dose were 5.53 ± 1.80 and 1.62 ± 0.41 mg/L, respectively. With maintenance dosing, AUCss,24 h was 79.6 ± 25.0 mg h/L and Css,avg 3.35 ± 1.06 mg/L. Monte Carlo simulations indicated that a 1 mg/kg/12-hourly maintenance dose could achieve >90% probability of target attainment (PTA) for isolates with minimum inhibitory concentration (MIC) ≤1 mg/L. PTA dropped substantially for MICs ≥2 mg/L, even with a maximally recommended daily dose of 1.5 mg/kg/12-hourly.Conclusion: This is the first clinical PK/PD study evaluating polymyxin B for BSI. These results will assist to optimize polymyxin B therapy and establish its breakpoints for CRKP BSI

美国小企业成长环境分析及对中国的启示 = An analysis on the growth environment of American small business : implications on China's small-medium enterprises

This dissertation analyzes the development of small and medium enterprises (SME) and economic conditions for their development in U.S.A.​Master of Science (Managerial Economics

Photocatalytic H2 or O2 Evolution over A-Site Deficient Perovskite-Type Compounds La1/3MO3 (M = Nb, Ta) from Aqueous Solutions

Two compounds La1/3MO3 (M = Nb, Ta) with A-site deficient perovskite-type structure were synthesized by the solid state reaction method. The photocatalytic properties of these compounds were characterized by H2 evolution with Pt cocatalyst from CH3OH/H2O solution and by O2 evolution from AgNO3 aqueous solution under UV light irradiation. The results showed that the average rate of H2 evolution was about 61.07 μmol h-1 for La1/3NbO3 and 95.79 μmol h-1 for La1/3TaO3 after 24 hours of reaction time, while the initial rate of O2 evolution was 26.31 μmol h-1 for La1/3NbO3 and 16.21 μmol h-1 for La1/3TaO3, respectively. H2 evolution was also observed over La1/3MO3 (M = Nb, Ta) with NiO cocatalyst from pure water under UV light irradiation

Intermolecular interactions of polysaccharides in membrane fouling during microfiltration

Membrane technology has been widely employed for seawater desalination, water and wastewater reclamation, while membrane fouling still remains as a major challenge. The polysaccharides in extracellular polymeric substances (EPS) have been recognized as an important foulant that causes serious membrane fouling, while the detailed structure of polysaccharides and the intermolecular interactions between them have not been adequately disclosed. In this study, two different polysaccharides and their mixtures were used to study the intermolecular cross-linking of polysaccharides as well as its effects on membrane fouling. Results demonstrated that the fouling propensities of distinct polysaccharides were completely different, which was attributed to the different intermolecular interactions lying in polysaccharides. The cross-linking among molecules of polysaccharide, regardless of the homogeneity, was found to form complex networks and determine the effective dimension of polysaccharides. Depending on the effective dimension of foulants, pore blocking and cake layer occurred subsequently during filtration processes. In light of this, it potentially gives new insights into the fouling behaviours by combining the structure-function knowledge of polysaccharides with their fouling propensity. In addition, transparent exopolymeric particles (TEP) measurement was found to provide an intuitionistic evaluation of the complex networks formed from polysaccharides, so that may act as a good indicator of fouling during membrane filtration

Adsorption and Desorption Behaviors of Four Endocrine Disrupting Chemicals in Soils from the Water-Level Fluctuation Zone of the Three Gorges Reservoir, China

As a special zone of periodic impoundment and flooding in the Three Gorges Reservoir (TGR), the water-level fluctuation zone (WLFZ) of TGR acts as a short-term ‘sink’ for hydrophobic endocrine disrupting compounds (EDCs). This study was conducted on the adsorption/desorption kinetics and equilibriums of four target EDCs (i.e., estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), and bisphenol A (BPA)) in soil samples (i.e., S1, S2, S3, and S4), which were collected from different elevation gradients of the WLFZ at Qingxi Town of Fulin in TGR. Under the influence of the water-level fluctuation, S1 and S2 from the frequent inundation area had smaller particle sizes with more organic matter (OM) and total nitrogen (TN) content, whereas soils S3 and S4 from the long-term exposed area had a higher fraction of sand with lower OM and TN. All four target EDCs could achieve an adsorption equilibrium within 24 h, and the kinetics of the adsorption/desorption fitted the pseudo-second-order model excellently. The adsorption/desorption isotherms of the EDCs were better described by the Freundlich equation. The adsorption capacity decreased, as 17α-ethynylestradiol (EE2) > 17β-estradiol (E2) > estrone (E1) > bisphenol A (BPA), in each tested soil. S1 and S2 exhibited a greater capacity but a lower degree of nonlinearity to adsorb the target EDCs than S3 and S4. The values of the Gibbs free energy suggested that the EDCs adsorption in the tested soils was dominated by unstable physical adsorption. The desorption hysteresis of E1, E2, and EE2 were stronger in S1 and S2, whereas the BPA exhibited weak or almost no hysteresis in all of the tested soils. The substantial water-level fluctuation imposed on the TGR would have a continuous influence on the EDCs adsorption/desorption by altering the soil properties. Thus, long-term monitoring and further research of EDCs in this region are urgent

Cerebrospinal fluid from patients with amyotrophic lateral sclerosis inhibits sonic hedgehog function.

Sonic hedgehog (Shh) is a morphogen essential to the developing nervous system that continues to play an important role in adult life by contributing to cell proliferation and differentiation, maintaining blood-brain barrier integrity, and being cytoprotective against oxidative and excitotoxic stress, all features of importance in amyotrophic lateral sclerosis (ALS). ALS is a fatal disease characterized by selective loss of motor neurons due to poorly understood mechanisms. Evidence indicates that Shh might play an important role in ALS, and that Shh signaling might be also adversely affected in ALS. Since little is known about the functional status of Shh pathway in patients with ALS, we therefore sought to determine whether Shh protein levels or biological activity in cerebrospinal fluid (CSF) was less in ALS patients than controls, and whether these measures could be correlated with ALS disease severity and disease progression, and with other CSF analytes of biological interest in ALS. Comparing Shh levels in the CSF of normal controls (n = 13), neurological controls (n = 12), and ALS patients (n = 9) measured by ELISA, we found that CSF Shh levels were not different between controls and ALS patients. However, when assessing Shh biological activity in CSF using in vitro cell-based assays, which measure Shh activity as inducible Gli-driven luminescence, we found that in the presence of exogenous recombinant Shh or the Shh agonist, purmorphamine, the inducible activity of CSF was significantly augmented in the control groups as expected, but not in the ALS group, suggesting the presence of an inhibitor of Shh signaling in ALS CSF samples. Since purmorphamine acts on Smoothened, downstream of Shh and its receptor Patched, the inhibitory action is downstream of Smoothened. Our results also demonstrated that while the inhibitory effect of ALS CSF on Shh signaling did not correlate significantly with ALS disease characteristics, the levels of IL-1β and TNF-α did. In addition to being significantly elevated in ALS CSF, these cytokines negatively correlated with the disease duration, whereas GDF11 was a favorable predictor of ALS clinical score. We also found that TNF-α significantly inhibited Shh biological activity in vitro, potentially suggesting a novel role of TNF-α in ALS pathogenesis. Collectively, this is the first report demonstrating that Shh signaling in CSF of ALS patients is compromised