Bandwidth reduction for remote navigation systems through view prediction and progressive transmission

Remote navigation systems, such as exploration of virtual 3D worlds or remote surgery, usually require higher bandwidth than the Internet connection commonly available at home. In this paper, we explore a set of techniques to reduce the bandwidth required by these applications. Our system consists of a client PC equipped with a graphics card, and a remote high-end server. The server hosts the remote environment and does the actual rendering of the scenes for several clients, and the new image is passed to them. This scheme is suitable when the data has a copyright or when its size may exceed the rendering capabilities of the client. The general scheme is the following: each time the position changes, the new view is predicted by both the client and the server and the difference information between the predicted view and the correct one is sent to the client. To reduce bandwidth we can improve the prediction method, and the transmission system. We present here two groups of techniques: First, a set of lossless methods which achieve reductions of up to a 9:1 ratio. These are a combination of a two-level forward warping, that takes advantage of spatial coherence, and a masking method, which allows to transmit only the information that really needs to be updated. Second, a set of lossy methods suitable for very low bandwidth environments which involve both progressive transmission and image reuse. They consider relevant parameters such as the number of pixels, the amount of information they provide, and their colour deviation in order to create a strategy for prioritizing the information transmission. This system allows to improve up to an additional 4:1 ratio. The quality of the generated images is very high, and often indistinguishable from the correct ones.     

Influence of graphene-based compounds on the mechanical toughness and thermal stability of polypropylene

A study of the improvement of the mechanical and thermal properties of nanocomposites prepared with polypropylene (PP) and different graphene samples [graphene oxide (GO), reduced GO (RGO), and commercial graphene (G)] is presented. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy characterization were applied to the graphene samples. The nanocomposites were characterized by thermogravimetric analysis, XRD, differential scanning calorimetry, transmission electron microscopy (TEM), tensile, and impact resistance tests. PP/RGO nanocomposites showed significant improvement in mechanical and thermal properties. Sample PP/RGO-0.75 resulted in an increment in Young's modulus (51%), tensile strength (24%), and elongation at break (15%). This is attributed to a good dispersion state, a higher crystallinity percentage, and a good interfacial adhesion between PP and RGO. Sample PP/RGO-0.50 exhibited an increase of 197 °C in the temperature at which a loss in weight of 5% occurred, compared to that for pure PP. The height of stacked layers calculated by XRD measurements was similar to the value observed by TEM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48258.     

Acidity and DAG Content of Olive Oils Recently Produced on the Island of Mallorca

In this study, the quality characteristics, i.e., the acidity and acylglycerols, of currently produced Mallorcan oil was analyzed by titration and gas-chromatographic technique, respectively, in approximately 400 samples of monovarietal olive oil made from three genetic varieties (Arbequina, Empeltre, and Picual) on the island of Mallorca during the 2003/2004 and 2005/2006 seasons, and the differences in the compositions were discussed. Composition analysis showed that free fatty acids (FFAs) and DAGs were produced mainly by hydrolysis of triacylglycerols (TAGs). Fruit storage tests revealed that hydrolysis occurred during storage of olive fruits. The DAG content was higher in oil with higher acidity, but the maximal DAG content was only about 10 with 30% acidity, and the primary isomer found in Mallorcan oil was 1,3-DAG. However, the chiral-chromatographic study on the ratio of sn-1,2-DAG to the sum of sn-1,2-DAG and sn-2,3-DAG in a slightly hydrolyzed oil sample indicated that Empeltre and Picual fruits possess an sn-3-enantioselective lipase that leads to accumulation of sn-1,2-DAG. In currently produced Mallorcan oil, significant isomerization appears to occur and hydrolysis of the resulting 1,3-DAGs seems to lessen DAG accumulation.     

Influence of fabrication parameters in cellular microarrays for stem cell studies

Lately there has been an increasing interest in the development of tools that enable the high throughput analysis of combinations of surface-immobilized signaling factors and which examine their effect on stem cell biology and differentiation. These surface-immobilized factors function as artificial microenvironments that can be ordered in a microarray format. These microarrays could be useful for applications such as the study of stem cell biology to get a deeper understanding of their differentiation process. Here, the evaluation of several key process parameters affecting the cellular microarray fabrication is reported in terms of its effects on the mesenchymal stem cell culture time on these microarrays. Substrate and protein solution requirements, passivation strategies and cell culture conditions are investigated. The results described in this article serve as a basis for the future development of cellular microarrays aiming to provide a deeper understanding of the stem cell differentiation process.     

Analysis and Simulation of distributed nonlinearities in ferroelectrics and superconductors for microwave applications

This paper gives closed-form equations for the intermodulation and third harmonic signals generated in a nonlinear transmission line with distributed quadratic nonlinearities in the conductor and dielectric. Although the formulation developed is general, it is intended to be used in planar devices combining high-temperature superconductor (HTS) and oxide ferroelectrics. The analysis in this paper shows that the intermodulation and third harmonic signals produced by an HTS tend to cancel those of a ferroelectric, and that full cancellation is theoretically possible. This opens the way for using HTS/ferroelectric multilayers, not (only) for their tunable or phase-shifting properties, but for highly linear spurious-free planar HTS devices.     

Experiments and Model of Intermodulation Distortion in a Rutile Resonator with Y-Ba2-Cu3-O7?δ Endplates

We have derived general equations to calculate intermodulation distortion in resonators with high temperature superconducting (HTS) films which are not restricted to a specific resonator shape and may be used whenever the fields in a resonator generate currents on the surface of one or more HTS films. These equations are applied to rutile-loaded cavities with one or two 10 × 10 mm² Y-Ba₂-Cu₃-O^7– endplates and are used to extract parameters characterizing the nonlinearities of these films from intermodulation measurements. Even though the films have similar small-signal performance, we have found large variation in the strength of their nonlinearities.     

Resveratrol as an anti-inflammatory and anti-aging agent: mechanisms and clinical implications

Resveratrol is a phytoalexin polyphenolic compound found in various plants, including grapes, berries, and peanuts. Multiple lines of compelling evidence indicate its beneficial effects on neurological, hepatic, and cardiovascular systems. Also one of the most striking biological activities of resveratrol soundly investigated during the late years has been its cancer-chemopreventive potential. In fact, recently it has been demonstrated that this stilbene blocks the multistep process of carcinogenesis at various stages: tumor initiation, promotion, and progression. One of the possible mechanisms for its biological activities involves downregulation of the inflammatory response through inhibition of synthesis and release of pro-inflammatory mediators, modification of eicosanoid synthesis, inhibition of activated immune cells, or inhibiting such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) via its inhibitory effects on nuclear factor (kappa)B (NF-(kappa)B) or the activator protein-1 (AP-1). More recent data provide interesting insights into the effect of this compound on the lifespan of yeast and flies, implicating the potential of resveratrol as an anti-aging agent in treating age-related human diseases. It is worthy to note that the phenolic compound possesses a low bioavailability and rapid clearance from the plasma. As the positive effects of resveratrol on inflammatory response regulation may comprise relevant clinical implications, the purpose of this article is to review its strong anti-inflammatory activity and the plausible mechanisms of these effects. Also, this review is intended to provide the reader an up-date of the bioavailability and pharmacokinetics of resveratrol and its impact on lifespan.     

Interaction of porosity with a planar solid/liquid interface

In this article, an investigation of the interaction between gas porosity and a planar solid/liquid (SL) interface is reported. A two-dimensional numerical model able to accurately track sharp SL interfaces during solidification of pure metals and alloys is proposed. The finite-difference method and a rectangular undeformed grid are used for computation. The SL interface is described through the points of intersection with the grid lines. Its motion is determined by the thermal and solute gradients at each particular point. Changes of the interface temperature because of capillarity or solute redistribution as well as any perturbation of the thermal and solute field produced by the presence of non-metallic inclusions can be computed. To validate the model, the dynamics of the interaction between a gas pore and a solidification front in metal alloys was observed using a state of the art X-ray transmission microscope (XTM). The experiments included observation of the distortion of the SL interface near a pore, real-time measurements of the growth rate, and the change in shape of the porosity during interaction with the SL interface in pure Al and Al-0.25 wt pct Au alloy. In addition, porosity-induced solute segregation patterns surrounding a pore were also quantified.     

Chemopreventive effect of dietary curcumin on inflammation‐induced colorectal carcinogenesis in mice

Scope: Curcumin is a polyphenol with a variety of pharmacologic effects. We evaluate the effect of dietary curcumin on the severity of repeated colitis‐associated colorectal cancer. Methods and results: Six‐week‐old C57BL/6 mice were randomized into two dietary groups: standard diet and curcumin at 0.6% diet. The mice were exposed to 15 cycles of 0.7% dextran sodium sulphate for 1 week followed by distilled water for 10 days. After curcumin diet, the disease activity index presented a statistical reduction in the last cycles, macroscopic tumors were not seen and the microscopic study showed minor neoplasic lesions with respect to standard diet‐group. β‐Catenin translocation to the cytoplasm and/or nucleus was observed in the tumor tissue, but this translocation and its intensity were significantly minor in the curcumin diet‐DSS animals. Cytokines as tumor necrosis factor‐α and IFN‐γ were significantly diminished in DSS‐animals fed with curcumin. Conversely, non‐modification of p53 expression was observed and cyclo‐oxygenase‐2 and inducible nitric oxide synthase were significantly reduced in the curcumin diet‐DSS group. Conclusion: We demonstrate the protective/preventive effect of curcumin in the progression of colorectal cancer associated to colitis, which was correlated with a lowered immunoreactivity of ß‐catenin, a non‐modification of p53 expression, a reduction of proinflammatory cytokine levels and a decrease of inflammatory protein overexpression.     

Unequal spatial distribution of retrofits in Bucharest’s apartment buildings

This paper argues that the current spatial patterns of energy retrofits in post-socialist apartment buildings are unequally distributed across municipalities in Bucharest, Romania. In addition to the dominant techno-economic and social framing of this type of retrofit action, an institutional and political perspective can provide useful insights into why this occurs. By drawing on secondary analysis of statistical data, grey literature and 20 semi-structured interviews in Bucharest, three important findings emerge. First, the institutional complexity of energy retrofit of apartment buildings in Romania is underestimated and the interaction between various institutions is poor, explained by lack of trust and collective action. Second, the spatial distribution of the retrofit of apartment buildings is unequally distributed across Bucharest’s six municipalities. Third, current action for retrofit does not reach municipalities with the greatest need and potential. A more bottom-up and decentralized institutional landscape exists than is currently acknowledged in public policy and the research literature. Findings show an unequal and unfair spread of retrofit action within and between cities – raising wider implications for the potential shortcomings of European Union retrofit programmes in Central and Eastern Europe.