Shearlets and Optimally Sparse Approximations

Multivariate functions are typically governed by anisotropic features such as edges in images or shock fronts in solutions of transport-dominated equations. One major goal both for the purpose of compression as well as for an efficient analysis is the provision of optimally sparse approximations of such functions. Recently, cartoon-like images were introduced in 2D and 3D as a suitable model class, and approximation properties were measured by considering the decay rate of the $L^2$ error of the best $N$-term approximation. Shearlet systems are to date the only representation system, which provide optimally sparse approximations of this model class in 2D as well as 3D. Even more, in contrast to all other directional representation systems, a theory for compactly supported shearlet frames was derived which moreover also satisfy this optimality benchmark. This chapter shall serve as an introduction to and a survey about sparse approximations of cartoon-like images by band-limited and also compactly supported shearlet frames as well as a reference for the state-of-the-art of this research field.Comment: in "Shearlets: Multiscale Analysis for Multivariate Data", Birkh\"auser-Springe

Microalgae biomass from swine wastewater and its conversion to bioenergy

© 2018 Elsevier Ltd Ever-increasing swine wastewater (SW) has become a serious environmental concern. High levels of nutrients and toxic contaminants in SW significantly impact on the ecosystem and public health. On the other hand, swine wastewater is considered as valuable water and nutrient source for microalgae cultivation. The potential for converting the nutrients from SW into valuable biomass and then generating bioenergy from it has drawn increasing attention. For this reason, this review comprehensively discussed the biomass production, SW treatment efficiencies, and bioenergy generation potentials through cultivating microalgae in SW. Microalgae species grow well in SW with large amounts of biomass being produced, despite the impact of various parameters (e.g., nutrients and toxicants levels, cultivation conditions, and bacteria in SW). Pollutants in SW can effectively be removed by harvesting microalgae from SW, and the harvested microalgae biomass elicits high potential for conversion to valuable bioenergy

New and practical mathematical model of membrane fouling in an aerobic submerged membrane bioreactor

© 2017 Elsevier Ltd This study aimed to develop a practical semi-empirical mathematical model of membrane fouling that accounts for cake formation on the membrane and its pore blocking as the major processes of membrane fouling. In the developed model, the concentration of mixed liquor suspended solid is used as a lumped parameter to describe the formation of cake layer including the biofilm. The new model considers the combined effect of aeration and backwash on the foulants’ detachment from the membrane. New exponential coefficients are also included in the model to describe the exponential increase of transmembrane pressure that typically occurs after the initial stage of an MBR operation. The model was validated using experimental data obtained from a lab-scale aerobic sponge-submerged membrane bioreactor (MBR), and the simulation of the model agreed well with the experimental findings

Anterior cingulate cortex is crucial for contra- but not ipsi-lateral electro-acupuncture in the formalin-induced inflammatory pain model of rats

Acupuncture and electro-acupuncture (EA) are now widely used to treat disorders like pain. We and others have shown previously that current frequency, intensity and treatment duration all significantly influence the anti-nociceptive effects of EA. There is evidence that stimulating sites also affect the antinociception, with EA applied ipsilaterally to the pain site being more effective under some pain states but contralateral EA under others. It was recently reported that local adenosine A1 receptors were responsible for ipsilateral acupuncture, but what mechanisms specifically mediate the anti-nociceptive effects of contralateral acupuncture or EA remains unclear. In the present study, we applied 100 Hz EA on the ipsi- or contra-lateral side of rats with inflammatory pain induced by intra-plantar injection of formalin, and reported distinct anti-nociceptive effects and mechanisms between them. Both ipsi- and contra-lateral EA reduced the paw lifting time in the second phase of the formalin test and attenuated formalin-induced conditioned place aversion. Contralateral EA had an additional effect of reducing paw licking time, suggesting a supraspinal mechanism. Lesions of rostral anterior cingulate cortex (ACC) completely abolished the anti-nociceptive effects of contra- but not ipsi-lateral EA. These findings were not lateralized effects, since injection of formalin into the left or right hind paws produced similar results. Overall, these results demonstrated distinct anti-nociceptive effects and mechanisms between different stimulating sides and implied the necessity of finding the best stimulating protocols for different pain states

Bioprocessing for elimination antibiotics and hormones from swine wastewater

© 2017 Elsevier B.V. Antibiotics and hormones in swine wastewater have become a critical concern worldwide due to the severe threats to human health and the eco-environment. Removal of most detectable antibiotics and hormones, such as sulfonamides (SAs), SMs, tetracyclines (TCs), macrolides, and estrogenic hormones from swine wastewater utilizing various biological processes were summarized and compared. In biological processes, biosorption and biodegradation are the two major removal mechanisms for antibiotics and hormones. The residuals in treated effluents and sludge of conventional activated sludge and anaerobic digestion processes can still pose risks to the surrounding environment, and the anaerobic processes’ removal efficiencies were inferior to those of aerobic processes. In contrast, membrane bioreactors (MBRs), constructed wetlands (CWs) and modified processes performed better because of their higher biodegradation of toxicants. Process modification on activated sludge, anaerobic digestion and conventional MBRs could also enhance the performance (e.g. removing up to 98% SMs, 88.9% TCs, and 99.6% hormones from wastewater). The hybrid process combining MBRs with biological or physical technology also led to better removal efficiency. As such, modified conventional biological processes, advanced biological technologies and MBR hybrid systems are considered as a promising technology for removing toxicants from swine wastewater

Problematic effects of antibiotics on anaerobic treatment of swine wastewater

© 2018 Elsevier Ltd Swine wastewaters with high levels of organic pollutants and antibiotics have become serious environmental concerns. Anaerobic technology is a feasible option for swine wastewater treatment due to its advantage in low costs and bioenergy production. However, antibiotics in swine wastewater have problematic effects on micro-organisms, and the stability and performance of anaerobic processes. Thus, this paper critically reviews impacts of antibiotics on pH, COD removal efficiencies, biogas and methane productions as well as the accumulation of volatile fatty acids (VFAs) in the anaerobic processes. Meanwhile, impacts on the structure of bacteria and methanogens in anaerobic processes are also discussed comprehensively. Furthermore, to better understand the effect of antibiotics on anaerobic processes, detailed information about antimicrobial mechanisms of antibiotics and microbial functions in anaerobic processes is also summarized. Future research on deeper knowledge of the effect of antibiotics on anaerobic processes are suggested to reduce their adverse environmental impacts

Influences of affiliated components and train length on the train wind

The induced airflow from passing trains, which is recognized as train wind, usually has adverse impacts on people in the surroundings, i.e., the aerodynamic forces generated by a high-speed train&#39;s wind may act on the human body and endanger the safety of pedestrians or roadside workers. In this paper, an improved delayed detached eddy simulation (IDDES) method is used to study train wind. The effects of the affiliated components and train length on train wind are analyzed. The results indicate that the affiliated components and train length have no effect on train wind in the area in front of the leading nose. In the downstream and wake regions, the longitudinal train wind becomes stronger as the length of the train increases, while the transverse train wind is not affected. The presence of affiliated components strengthens the train wind in the near field of the train because of strong flow solid interactions but has limited effects on train wind in the far field.</span

Dynamical Axion Field in Topological Magnetic Insulators

Axions are very light, very weakly interacting particles postulated more than 30 years ago in the context of the Standard Model of particle physics. Their existence could explain the missing dark matter of the universe. However, despite intensive searches, they have yet to be detected. In this work, we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In particular, we show that the axion coupling enables a nonlinear modulation of the electromagnetic field, leading to attenuated total reflection. We propose a novel optical modulators device based on this principle.Comment: 5 pages, 3 figure

Oncolytic viruses as therapeutic cancer vaccines

Oncolytic viruses (OVs) are tumor-selective, multi-mechanistic antitumor agents. They kill infected cancer and associated endothelial cells via direct oncolysis, and uninfected cells via tumor vasculature targeting and bystander effect. Multimodal immunogenic cell death (ICD) together with autophagy often induced by OVs not only presents potent danger signals to dendritic cells but also efficiently cross-present tumor-associated antigens from cancer cells to dendritic cells to T cells to induce adaptive antitumor immunity. With this favorable immune backdrop, genetic engineering of OVs and rational combinations further potentiate OVs as cancer vaccines. OVs armed with GM-CSF (such as T-VEC and Pexa-Vec) or other immunostimulatory genes, induce potent anti-tumor immunity in both animal models and human patients. Combination with other immunotherapy regimens improve overall therapeutic efficacy. Coadministration with a HDAC inhibitor inhibits innate immunity transiently to promote infection and spread of OVs, and significantly enhances anti-tumor immunity and improves the therapeutic index. Local administration or OV mediated-expression of ligands for Toll-like receptors can rescue the function of tumor-infiltrating CD8+ T cells inhibited by the immunosuppressive tumor microenvironment and thus enhances the antitumor effect. Combination with cyclophosphamide further induces ICD, depletes Treg, and thus potentiates antitumor immunity. In summary, OVs properly armed or in rational combinations are potent therapeutic cancer vaccines. © 2013 Bartlett et al.; licensee BioMed Central Ltd

A robotic crawler exploiting directional frictional interactions: Experiments, numerics and derivation of a reduced model

We present experimental and numerical results for a model crawler which is able to extract net positional changes fromreciprocal shape changes, i.e. 'breathinglike' deformations, thanks to directional, frictional interactions with a textured solid substrate, mediated by flexible inclined feet. We also present a simple reduced model that captures the essential features of the kinematics and energetics of the gait, and compare its predictions with the results from experiments and from numerical simulations