This paper proposes a distributed dual gradient tracking algorithm (DDGT) to solve resource allocation problems over an unbalanced network, where each node in the network holds a private cost ...function and computes the optimal resource by interacting only with its neighboring nodes. Our key idea is the novel use of the distributed push-pull gradient algorithm (PPG) to solve the dual problem of the resource allocation problem. To study the convergence of the DDGT, we first establish the sublinear convergence rate of PPG for non-convex objective functions, which advances the existing results on PPG as they require the strong-convexity of objective functions. Then we show that the DDGT converges linearly for strongly convex and Lipschitz smooth cost functions, and sublinearly without the Lipschitz smoothness. Finally, experimental results suggest that DDGT outperforms existing algorithms.
Fe‐based oxides have been seldom reported as electrocatalysts for the hydrogen evolution reaction (HER), limited by their weak intrinsic activity and conductivity. Herein, phosphorus doping ...modulation is used to construct inverse spinel P‐Fe3O4 with dual active sites supported on iron foam (P‐Fe3O4/IF) for alkaline HER with an extremely low overpotential of 138 mV at 100 mA cm−2. The obtained inverse spinel Fe–O–P derived from controllable phosphorization can provide an octahedral Fe site and O atom, which bring about the unusual dissociation mechanisms of two water molecules to greatly accelerate the proton supply in alkaline media. Meanwhile, the ΔGH of the P atom in Fe–O–P as an active site is theoretically calculated to be 0.01 eV. Notably, the NiFe LDH/IF(+)||P‐Fe3O4/IF(−) couple achieves an onset potential of 1.47 V (vs RHE) for overall water splitting, with excellent stability for more than 1000 h at a current density of 1000 mA cm−2, and even for 25 000 s at 10 000 mA cm−2 in 6.0 m KOH at 60 °C. The excellent catalyst stability and low‐cost merits of P‐Fe3O4/IF may hold promise for industrial hydrogen production. This work may reveal a new design strategy of earth‐abundant materials for large‐scale water splitting.
The octahedral Fe and O in inverse spinel Fe–O–P bring about the unusual dissociation mechanisms of two water molecules for accelerating proton supply. The ΔGH of the P atom in Fe–O–P as an active site is theoretically proved to be 0.01 eV. Therefore, phosphorus doping modulation is a promising strategy for excellent electrocatalysts for hydrogen evolution reaction.
Tin‐based halide perovskites attract incremental attention due to the favorable optoelectronic properties and ideal bandgaps. However, the poor crystalline quality is still the biggest challenge for ...further progress in tin‐based perovskite solar cells (PVSCs) due to the unfavorable defects and uncontrollable crystallization kinetics. Here, acetic acid (HAc) is first introduced to reduce the supersaturated concentration of the precursor solution to preferentially form pre‐nucleation clusters, thus inducing rapid nucleation for effective regulation of crystallization kinetics. In particular, the hydrogen ion and acetate ion contained in HAc can effectively inhibit the oxidation of Sn2+, and the hydrogen bonding interaction between HAc and iodide ion (I‐) greatly reduces the loss of I‐, which guarantees the I‐/Sn2+ stoichiometric ratio of the corresponding perovskite film close to theoretical value, thus effectively reducing the defect density and maintaining the perfect crystal lattice. Consequently, the HAc‐assisted tin‐based PVSCs achieve a champion power conversion efficiency of 12.26% with superior open‐circuit voltage up to 0.75 V. Moreover, the unencapsulated device maintains nearly 90% of the initial PCE even after 3000 h storage in nitrogen atmosphere. This demonstrated strategy enables to prepare high‐quality tin‐based perovskite film with lower defect density and lattice distortion.
Acetic acid (HAc) is first introduced to reduce the supersaturated concentration of the precursor solution to form pre‐nucleation clusters, thus inducing rapid nucleation. In particular, the introduction of HAc can inhibit the oxidation of Sn2+ and reduce the loss of I‐. HAc‐assisted device deliver a champion efficiency of 12.26%, maintaining ≈90% of initial efficiency after storage in nitrogen over 3000 h.
Of the different branches of indoor localization research, WiFi fingerprinting has drawn significant attention over the past decade. These localization systems function by comparing WiFi received ...signal strength indicator (RSSI) and a pre-established location-specific fingerprint map. However, due to the time-variant wireless signal strength, the RSSI fingerprint map needs to be calibrated periodically, incurring high labor and time costs. In addition, biased RSSI measurements across devices along with transmission power control techniques of WiFi routers further undermine the fidelity of existing fingerprint-based localization systems. To remedy these problems, we propose GradIent FingerprinTing (GIFT) which leverages a more stable RSSI gradient. GIFT first builds a gradient-based fingerprint map (Gmap) by comparing absolute RSSI values at nearby positions, and then runs an online extended particle filter (EPF) to localize the user/device. By incorporating Gmap, GIFT is more adaptive to the time-variant RSSI in indoor environments, thus effectively reducing the overhead of fingerprint map calibration. We implemented GIFT on Android smartphones and tablets, and conducted extensive experiments in a five-story campus building. GIFT is shown to achieve an 80 percentile accuracy of 5.6 m with dynamic WiFi signals.
In this paper, ZnO/NiO composites rich in oxygen vacancies are prepared by the solvothermal method and reduction method. In the test, through the use of X-ray diffraction (XRD), X-ray photoelectron ...spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electron paramagnetic resonance (EPR), we effectively prove the existence of phase, morphology and oxygen vacancies in the material. Through the photocatalysis test and gas sensitivity test, it is found that 10% Ni doped OZN-10 has the best photocatalytic activity and gas sensitivity characteristics. The degradation rate of methylene blue (MB) was 98%. The gas sensitivity test shows that OZN-10 has good selectivity, good response performance (3000 ppm, 27,887%) and excellent response recovery time (response time: 50 s, recovery time: 5-7 s) for saturated NH
gas at standard atmospheric pressure (101.325 KPa) and room temperature (25 °C). The synergistic effect of oxygen vacancy as the center of a trap and p-n heterojunction forming an electric potential field at the interface is explained, and the mechanism of improving photocatalysis and gas sensitivity is analyzed. This work will provide an innovative vision for dual-performance oxygen vacancy modification of heterojunctions through photocatalysis.
The integrated energy system (IES) optimal scheduling under the comprehensive flexible operation mode of pumping storage is considered. This system is conducive to the promotion of the accommodation ...of wind and solar energy and can meet the water, electricity and heat needs of coastal areas far away from the energy center. In this study, the joint dispatch between double pumped storage power stations is used to accommodate wind and solar energy better and smooth their fluctuations on the grid. Through the scheduling of water between the high and low reservoirs of double pumped storage power stations and the reservoir of the seawater desalination plant, the impact of storage capacity constraints on pumped storage power plants is reduced. Moreover, the objective function to build the IES optimization scheduling model is to achieve minimum economic cost. The results reveal that the integrated energy system accommodates all wind energy and solar energy. As such, the system increases the average working time of the pumped storage unit by 1.9 hours and reduces the economic cost by 31.50%. Based on the simulation results, the model can enhance the accommodation capability of wind energy and solar energy and improve the system economy.
Interfacial lattice mismatch and adverse reaction are the key issues hindering the development of nickel oxide (NiOx)‐based inverted perovskite solar cells (PVSCs). Herein, a p‐chlorobenzenesulfonic ...acid (CBSA) self‐assembled small‐molecule (SASM) is adopted to anchor NiOx and perovskite crystals to endow dual‐passivation. The chlorine terminal of SASMs can provide growth sites for perovskite, leading to interfacial strain release. Meanwhile, the sulfonic acid group from SASMs can passivate surface defects of NiOx, conducive to charge carrier extraction. In addition, the self‐assembled layer inhibits the adverse interfacial reaction by preventing NiOx contact with perovskite. Therefore, the NiOx/CBSA‐based PVSCs obtain a champion power conversion efficiency (PCE) of 21.8%. Of particular note, the unencapsulated devices can retain above 80% of their initial PCE values after storage in a nitrogen atmosphere for 3000 h, in air with a relative humidity of 50–70% for 1000 h, and heating at 85 °C for 800 h, respectively.
A p‐chlorobenzenesulfonic acid (CBSA)‐based self‐assembled layer dual‐passivation strategy is employed to effectively eliminate interfacial lattice mismatch and detrimental reactions in NiOx‐based perovskite solar cells, which achieves unencapsulated devices preserving above 80% of initial efficiencies after storing in N2 for 3000 h, in air with a relative humidity of 50–70% for 1000 h, and heating at 85 °C for 800 h, respectively.
Cloud contamination is an inevitable problem in optical remote sensing images. Unlike thick clouds, thin clouds do not completely block out background which makes it possible to restore background ...information. In this paper, we propose a semi-supervised method based on generative adversarial networks (GANs) and a physical model of cloud distortion (CR-GAN-PM) for thin cloud removal with unpaired images from different regions. A physical model of cloud distortion which takes the absorption of cloud into consideration was also defined in this paper. It is worth noting that many state-of-the-art methods based on deep learning require paired cloud and cloud-free images from the same region, which is often unavailable or time-consuming to collect. CR-GAN-PM has two main steps: first, the cloud-free background and cloud distortion layers were decomposed from an input cloudy image based on GANs and the principles of image decomposition; then, the input cloudy image was reconstructed by putting those layers into the redefined physical model of cloud distortion. The decomposition process ensured that the decomposed background layer was cloud-free and the reconstruction process ensured that generated background layer was correlated with the input cloudy image. Experiments were conducted on Sentinel-2A imagery to validate the proposed CR-GAN-PM. Averaged over all testing images, the SSIMs values (structural similarity index measurement) of CR-GAN-PM were 0.72, 0.77, 0.81 and 0.83 for visible and NIR bands respectively. Those results were similar to the end-to-end deep learning-based methods and better than traditional methods. The number of input bands and values of hyper-parameters affected little on the performance of CR-GAN-PM. Experimental results show that CR-GAN-PM is effective and robust for thin cloud removal in different bands.
Abstract
Background
Multiple oral insulin-sensitizing agents, such as metformin, thiazolidinediones, inositols, and berberine, have been proven safe and efficacious in improving the endocrine, ...metabolic, and reproductive abnormalities seen in polycystic ovary syndrome (PCOS), providing more options for healthcare providers and patients. These oral insulin sensitizers are more convenient, practical, and economic than agents that need to be injected. A comparison of the clinical effectiveness of the four different classes of oral insulin sensitizers in PCOS has not been explored, leading to clinical uncertainty about the optimal treatment pathway. The present study aims to compare the effects of oral insulin sensitizers on endocrine and metabolic profiles in women with PCOS.
Methods
We identified randomized controlled trials for PCOS from a variety of databases, published from January 2005 to October 2020. Outcomes included changes in menstrual frequency, improvements in hyperandrogenism and glucolipid metabolism and adverse side effects. A random-effects network meta-analysis was performed.
Results
Twenty-two trials comprising 1079 patients with PCOS were included in this study. Compared with metformin, treatment with myo-inositol +
d
-chiro-inositol was associated with a greater improvement in menstrual frequency (odds ratio 14.70 95% confidence interval (CI) 2.31–93.58). Myo-inositol +
d
-chiro-inositol and metformin + thiazolidinediones combination therapies were superior to respective monotherapies in reducing total testosterone levels. Thiazolidinediones, metformin + thiazolidinediones, and myo-inositol +
d
-chiro-inositol were associated with a lower insulin resistance index (HOMA-IR) compared with that in metformin alone (mean differences: − 0.72 95% CI (− 1.11)–(− 0.34) to − 0.89 95% CI (− 1.460)–(− 0.32)). Metformin + thiazolidinediones treatment was associated with lower triglyceride levels compared with that in metformin and thiazolidinediones monotherapy, while thiazolidinediones was superior to metformin in increasing high-density lipoprotein cholesterol and decreasing fasting plasma glucose, triglycerides, low-density lipoprotein cholesterol, and gastrointestinal adverse events.
Conclusions
Ours is the first study to report that for women with PCOS, myo-inositol combined with
d
-chiro-inositol and metformin combined with thiazolidinediones appear superior to metformin alone in improving insulin resistance and decreasing total testosterone. Myo-inositol combined with
d
-chiro-inositol is particularly efficacious in menstrual recovery. Thiazolidinediones and metformin combined with thiazolidinediones improve lipid metabolism better than metformin alone.
Trial registration
PROSPERO CRD42020211524
Abstract
Objective
The purpose of this study was to review the effects of robot-assisted therapy (RT) for improving poststroke upper extremity motor impairment.
Methods
The PubMed, Embase, Medline, ...and Web of Science databases were searched from inception to April 8, 2020. Randomized controlled trials that were conducted to evaluate the effects of RT on upper extremity motor impairment poststroke and that used Fugl-Meyer assessment for upper extremity scores as an outcome were included. Two authors independently screened articles, extracted data, and assessed the methodological quality of the included studies using the Physiotherapy Evidence Database (PEDro) scale. A random-effects meta-analysis was performed to pool the effect sizes across the studies.
Results
Forty-one randomized controlled trials with 1916 stroke patients were included. Compared with dose-matched conventional rehabilitation, RT significantly improved the Fugl-Meyer assessment for upper extremity scores of the patients with stroke, with a small effect size (Hedges g = 0.25; 95% CI, 0.11-0.38; I2 = 45.9%). The subgroup analysis revealed that the effects of unilateral RT, but not that of bilateral RT, were superior to conventional rehabilitation (Hedges g = 0.32; 95% CI, 0.15-0.50; I2 = 55.9%). Regarding the type of robot devices, the effects of the end effector device (Hedges g = 0.22; 95% CI, 0.09–0.36; I2 = 35.4%), but not the exoskeleton device, were superior to conventional rehabilitation. Regarding the stroke stage, the between-group difference (ie, RT vs convention rehabilitation) was significant only for people with late subacute or chronic stroke (Hedges g = 0.33; 95% CI, 0.16-0.50; I2 = 34.2%).
Conclusion
RT might be superior to conventional rehabilitation in improving upper extremity motor impairment in people after stroke with notable upper extremity hemiplegia and limited potential for spontaneous recovery.
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