Nonmonotone Barzilai-Borwein Gradient Algorithm for ℓ1\ell_1-Regularized Nonsmooth Minimization in Compressive Sensing

This paper is devoted to minimizing the sum of a smooth function and a nonsmooth $\ell_1$-regularized term. This problem as a special cases includes the $\ell_1$-regularized convex minimization problem in signal processing, compressive sensing, machine learning, data mining, etc. However, the non-differentiability of the $\ell_1$-norm causes more challenging especially in large problems encountered in many practical applications. This paper proposes, analyzes, and tests a Barzilai-Borwein gradient algorithm. At each iteration, the generated search direction enjoys descent property and can be easily derived by minimizing a local approximal quadratic model and simultaneously taking the favorable structure of the $\ell_1$-norm. Moreover, a nonmonotone line search technique is incorporated to find a suitable stepsize along this direction. The algorithm is easily performed, where the values of the objective function and the gradient of the smooth term are required at per-iteration. Under some conditions, the proposed algorithm is shown to be globally convergent. The limited experiments by using some nonconvex unconstrained problems from CUTEr library with additive $\ell_1$-regularization illustrate that the proposed algorithm performs quite well. Extensive experiments for $\ell_1$-regularized least squares problems in compressive sensing verify that our algorithm compares favorably with several state-of-the-art algorithms which are specifically designed in recent years.Comment: 20 page

Immersive Disaster Training Schema Based on Team Role-Playing

The prevalence of inevitable natural and social disasters is increasing at an alarming rate. With the proliferation of media and Internet technologies, there is a growing awareness of the importance of disaster training. The paper aims to combine the techniques of immersive Virtual Reality (VR) and team-based role-playing to demonstrate a comprehensive disaster training schema to help participants practice safety skills and learn proper decision-making skills in the face of disasters. A VR dome and cylinder combined multidisplay system iwDome was used to immerse participants and provide a view of the overall training; the role of each team was presented through the appropriate Head Mounted Display (HMD) and connected desktop. Rather than just being passive spectators or game players, the participants received puzzles in the virtual scenario that required intra-team and inter-team collaboration to be solved. The scenarios applicable to the system were not restricted to a specific type of disaster, but could be customized, revealing significant application prospects. To test the motivation for improvement, a quality assessment and user experience survey were conducted. The results indicate that participants were more engaged through cooperation in the virtual training environment and could achieve greater learning gains. The correlation of age to user studies was also confirmed. The enhanced enthusiasm of participants for what is relatively standard disaster management demonstrates the promise of using team role-playing-based VR training for vital, but otherwise tedious disaster safety training

Clinical Features, Risk Factors, and Therapy of Epithelial Keratitis after Cataract Surgery

Purpose. The study aimed to assess the clinical characteristics, risk factors, and therapy of epithelial keratitis after cataract surgery. Methods. Medical data of 89 consecutive patients who developed epithelial keratitis after cataract surgery, including 37 patients with diabetes mellitus (37 eyes) and 52 patients without diabetes mellitus (52 eyes), were retrospectively reviewed. The clinical characteristics, risk factors, and therapy in those patients were evaluated. Results. The preoperative tear film function determined by the tear breakup time, meibomian gland atrophy score, and low tear meniscus height in diabetic patients was poorer than nondiabetic patients (P<0.001). Of diabetic patients, 83.78% (31/37) had been diagnosed with meibomian gland dysfunction before cataract surgery and treated with topical nonsteroidal anti-inflammatory drugs after cataract surgery for 44.69 ± 10.51 days, compared to 42.31% (22/52) of nondiabetic patients receiving the topical nonsteroidal anti-inflammatory treatment for 33.35 ± 5.16 days (both P<0.001). Epithelial lesions progressed within three to four days following cataract surgery in 59.46% (22/37) of diabetic patients, versus 30.77% (16/52) of the nondiabetic patients (P=0.025). Patients with combined meibomian gland dysfunction and epithelial defects accounted for 48.65% (18/37) in the diabetic group and 25.00% (13/52) in the nondiabetic group (P<0.001). In vivo confocal microscopy showed absence of subbasal never fibers in eyes with epithelial defects, and central corneal sensation was also significantly depressed in those eyes, but there was no significant difference between the two groups (P=0.227). Corneal ulceration and herpes simplex keratitis were found in 2.70% (1/37) and 5.41% (2/37) of diabetic patients, respectively. Amniotic membrane transplantation was required in 32.43% (12/37) of patients in the diabetic group, and the proportion was higher than 1.92% (1/52) in the nondiabetic group (P<0.001). Average healing time of the corneal epithelium in the diabetic group was 40.62 ± 20.0 days, much longer than 21.74 ± 6.94 days in the nondiabetic group (P=0.002). Conclusion. Epithelial keratitis after cataract surgery in diabetic patients has the characteristics of rapid development, severe epithelial damage, and slow repair of the corneal epithelium. Amniotic membrane transplantation is a good choice for persistent epithelial defects associated with such epithelial keratitis. Attention should be paid to the tear film function and use of topical nonsteroidal anti-inflammatory drugs in patients undergoing cataract surgery

Laboratory analyses of two explanted hydrophobic acrylic intraocular lenses

Two three-piece hydrophobic acrylic intraocular lenses (IOLs) were explanted from two patients at 7 and 9 years, respectively, after implantation, because of poor fundus visualisation and/or a clinically significant decrease in visual acuity related to their opacified IOLs. In addition to light microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, confocal laser scanning microscopy was used for the first time to observe the explanted IOLs. The clinical aspect seemed to correspond to the phenomenon of surface light scattering, while laboratory analyses showed dense glistenings in the central layer of the IOL optic, which had no change next to the surface. Further studies on these phenomena are needed

Corrosion behavior of Inconel 625 deposited metal in molten KCl-MgCl2

In order to investigate the corrosion behavior of Inconel 625 deposited metal in molten KCl and MgCl _2 , the corrosion behavior of deposited metal immersed in molten salt for 60 h at 700 °C and 900 °C was studied by static corrosion immersion method. X-ray diffraction (XRD) and Geminisem300 were used to systematically study the phase composition, corrosion morphology and element distribution of the deposited metal. The results show that: the corrosion weight loss of the deposited metal showed an increasing trend at both temperatures, but the increasing range was different in different time intervals. The corrosion weight loss of the deposited metal increased slowly in the first 10 h, and increased sharply in the 10 h–60 h. It can be found that 10 h is the cut-off point of corrosion behavior. The corrosion rate is 0.03 mm/year at 700 °C and 0.50 mm/year at 900 °C for 10 h. The corrosion resistance of the deposited metal at 700 °C is better than that at 900 °C, which is due to the formation of dense MgO on the surface of the deposited metal at 700 °C, which hinders the corrosion reaction; at 900 °C, the content of CrCl _3 on the surface of the deposited metal increases, resulting in a ‘shell breaking effect’, which destroys the MgO shell and forms NiCr _2 O _4 with spinel structure. Its corrosion resistance is thus weakened

Corrosion Behavior of Nitrogen-Containing Low-Nickel Weld Cladding in KCl-MgCl₂ Eutectic Molten Salt at 900 °C

In this paper, the element nitrogen (N) is used to partially replace the element nickel (Ni) in flux-cored wire. A 44%Ni-24%Cr-0.18N nitrogen-containing low-nickel flux-cored wire with excellent corrosion resistance is prepared. The corrosion behavior of nitrogen-containing low-nickel weld cladding and Inconel 625 weld cladding in 40 KCl + 60 MgCl2 (wt%) molten salt at 900 °C is studied. The results show that the selective dissolution of Cr occurs in both weld claddings. The corrosion resistance of the 44%Ni-24%Cr-0.18N nitrogen-containing low-nickel weld cladding is better than that of the Inconel 625 weld cladding. The reason is that added N can react with H+ in molten salt to generate NH4+, remove corrosive impurities of MgOH+ in molten salt and change the corrosion environment. N preferentially combines with Cr to form Cr2N, reduces the diffusion precipitation of Cr and improves the corrosion resistance

Multi-Time Scale Optimization Scheduling Strategy for Combined Heat and Power System Based on Scenario Method

The wind–heat conflict and wind power uncertainty are the main factors leading to the phenomenon of wind curtailment during the heating period in the northern region of China. In this paper, a multi-time scale optimal scheduling strategy for combined heat and power system is proposed. Considering the temporal dependence of wind power fluctuation, the intra-day wind power scenario generation method is put forward, and both day-ahead and intra-day optimization scheduling models based on the scenario method are established to maximize the system’s revenue. The case analyzes the impacts of the initial heat storage capacity of a heat storage device and different scheduling strategies on system revenue. It is verified that the scheduling strategy can better adapt to wind power uncertainty and improve the absorption capacity of wind power, while ensuring the safety and economical efficiency of system operation

Dichloroacetate enhances adriamycin-induced hepatoma cell toxicity in vitro and in vivo by increasing reactive oxygen species levels.

A unique bioenergetic feature of cancer, aerobic glycolysis is considered an attractive therapeutic target for cancer therapy. Recently, dichloroacetate (DCA), a small-molecule metabolic modulator, was shown to reverse the glycolytic phenotype, induce reactive oxygen species (ROS) generation, and trigger apoptosis in various tumor cells. In this work, the capacity of DCA to enhance Adriamycin (ADM) efficacy in hepatoma cells by modulating glucose metabolism and redox status was evaluated. Two human hepatoma (HCC-LM3 and SMMC-7721) and a normal liver (LO2) cell lines were treated with DCA or ADM alone, or in combination. Exposure of hepatoma cells to DCA/ADM combination resulted in significantly decreased cell viability and increased percentage of apoptotic cells as well as intracellular ROS levels, in comparison with treatment with DCA or ADM alone. However, simultaneous treatment with the thiol antioxidant N-acetylcysteine (NAC, 10 mmol/L) reduced the elevated ROS levels and protected hepatoma cells from the cytotoxic effects of DCA/ADM combination. L-buthionine-[S,R]-sulfoximine, an inhibitor of glutathione synthesis, enhanced hepatoma cell sensitivity to DCA/ADM combination. Interestingly, treatment with DCA/ADM combination did not significantly increase cytotoxicity in normal hepatocytes in comparison with the drugs administered individually. Finally, DCA reduced tumor growth and enhanced ADM efficacy on HCC-LM3 hepatoma in mice. Overall, our data suggest that DCA enhances ADM cytotoxicity in hepatoma cells by increasing intracellular ROS levels and provide a strong biochemical rationale for the use of DCA in combination with ADM for treatment of hepatoma