Saliency-driven rate-distortion optimization for 360-degree image coding

Multimedia Tools and Applications - 360-degree images allow an immersive experience. They offer multiple views of a scene and the viewpoint can be selected by the user. However, the huge amount of...     

Evolution in the natural rubber native structure and plasticity retention index from the first tapping of clonal trees

This study was carried out with five rubber clones planted in Côte d'Ivoire from the first tapping up to the 18th month of tree tapping (1 tapping/4 days). Changes in the natural rubber native mesostructure (macromolecular structure, macrogel, and microgel) of films prepared from fresh field latex were monitored. At the same time, the evolution of the thermooxidation sensitivity of raw rubber samples [grade 10 technically specified rubber (TSR10)] was also monitored with the plasticity retention index (PRI). The substantial initial macrogel rate (70–86%, depending on the clone) fell during the first 18 months of tree tapping to reach a few percent. However, during the same period, the initially low microgel rate (5–15%) increased and then remain stabilized around 55% rubber. The macromolecular structure [weight‐average molecular weight (M_w) and molar mass distribution (MMD)] also changed after tree opening. M_w increased and stabilized after 7.5 months of tapping. The bimodal MMD primarily involved short chains (molar mass < 400 kg/mol) at the opening of the trees. The TSR10 samples, prepared with latex from virgin trees, showed high PRIs and, therefore, low sensitivity to thermooxidation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 903–909, 2005     

Delivery of a Therapeutic Protein for Bone Regeneration from a Substrate Coated with Graphene Oxide

The therapeutic efficacy of drugs often depends on the drug delivery carrier. For efficient delivery of therapeutic proteins, delivery carriers should enable the loading of large doses, sustained release, and retention of the bioactivity of the therapeutic proteins. Here, it is demonstrated that graphene oxide (GO) is an efficient carrier for delivery of therapeutic proteins. Titanium (Ti) substrates are coated with GO through layer‐by‐layer assembly of positively (GO‐NH₃⁺) and negatively (GO‐COO^?) charged GO sheets. Subsequently, a therapeutic protein (bone morphogenetic protein‐2, BMP‐2) is loaded on the GO‐coated Ti substrate with the outermost coating layer of GO‐COO^?(Ti/GO‐). The GO coating on Ti substrate enables loading of large doses and the sustained release of BMP‐2 with preservation of the structure and bioactivity of the drug. The extent of in vitro osteogenic differentiation of human bone marrow‐derived mesenchymal stem cells is higher when they are cultured on Ti/GO‐ carrying BMP‐2 than when they are cultured on Ti with BMP‐2. Eight weeks after implantation in mouse models of calvarial defects, the Ti/GO‐/BMP‐2 implants show more robust new bone formation compared with Ti, Ti/GO‐, or Ti/BMP‐2 implants. Therefore, GO is an effective carrier for the controlled delivery of therapeutic proteins, such as BMP‐2, which promotes osteointegration of orthopedic or dental Ti implants.     

Anterior segment sparing to reduce charged particle radiotherapy complications in uveal melanoma

PURPOSE: The purpose of this investigation is to delineate the risk factors in the development of neovascular glaucoma (NVG) after helium-ion irradiation of uveal melanoma patients and to propose treatment technique that may reduce this risk. METHODS AND MATERIALS: 347 uveal melanoma patients were treated with helium-ions using a single-port treatment technique. Using univariate and multivariate statistics, the NVG complication rate was analyzed according to the percent of anterior chamber in the radiation field, tumor size, tumor location, sex, age, dose, and other risk factors. Several University of California San Francisco-Lawrence Berkeley National Laboratory (LBNL) patients in each size category (medium, large, and extralarge) were retrospectively replanned using two ports instead of a single port. By using appropriate polar and azimuthal gaze angles or by treating patients with two ports, the maximum dose to the anterior segment of the eye can often be reduced. Although a larger volume of anterior chamber may receive a lower dose by using two ports than a single port treatment. We hypothesize that this could reduce the level of complications that result from the irradiation of the anterior chamber of the eye. Dose-volume histograms were calculated for the lens, and compared for the single and two-port techniques. RESULTS: NVG developed in 121 (35%) patients. The risk of NVG peaked between 1 and 2.5 years posttreatment. By univariate and multivariate analysis, the percent of lens in the field was strongly correlated with the development of NVG. Other contributing factors were tumor height, history of diabetes, and vitreous hemorrhage. Dose-volume histogram analysis of single-port vs. two-port techniques demonstrate that for some patients in the medium and large category tumor groups, a significant decrease in dose to the structures in the anterior segment of the eye could have been achieved with the use of two ports. CONCLUSION: The development of NVG after helium-ion irradiation is correlated to the amount of lens, anterior chamber in the treatment field, tumor height, proximity to the fovea, history of diabetes, and the development of vitreous hemorrhage. Although the influence of the higher LET deposition of helium-ions is unclear, this study suggests that by reducing the dose to the anterior segment of the eye may reduce the NVG complications. Based on this retrospective analysis of LBNL patients, we have implemented techniques to reduce the amount of the anterior segment receiving a high dose in our new series of patients treated with protons using the cyclotron at the UC Davis Crocker Nuclear Laboratory (CNL).     

Reliability of single strength under n-stresses

In this paper we have considered the reliability of a system when n-stresses acted on a single strength component with probability distributions that were exponential, normal and gamma. We infer that when n-stresses act on a single strength component with an exponential distribution, the component has the same reliability as single stress and strength components which are connected in series, whereas normal and gamma distributions do not follow this rule.     

Connectivity test for circuit detection

A new connectivity algorithm is proposed for testing whether a circ (a ring sum of two or more f-circuits) of a graph passes for a circuit or not, which is superior to the existing one. The labour involved in the proposed algorithm is proportional to n, as compared to the en of the old algorithm, where e and n represent the number of edges and nodes, respectively, of the graph.     

Effect of a non-uniform temperature gradient on the onset of oscillatory Bénard-Marangoni convection of an electrically conducting liquid in a magnetic field

This study deals theoretically with the effect of a non-uniform basic temperature gradient on the linear stability of the oscillatory Bénard-Marangoni convection in a horizontal layer of a viscous quiescent, electrically conducting fluid in the presence of a uniform vertical magnetic field. The upper surface of a fluid layer is deformably free and the lower surface is rigid. The eigenvalue equations of the perturbed state obtained from the normal mode analysis are solved by using the fourth order Runge-Kutta-Gill’s method with the shooting technique. The results show that the critical Rayleigh number Ra_c and the critical Marangoni number −Ma_c become larger as the Chandrasekhar number Q or the Biot number Bi of the upper free surface increases, and the Crispation number Cr decreases. When compared with the linear temperature profile, the inverted parabolic temperature profile indicates a reinforcement of stability, while the parabolic temperature profile indicates a diminution of stability in both Rayleigh-Bénard and Bénard-Marangoni convections. In addition, for the piecewise linear temperature profiles, the influences of thermal depth on the critical conditions are also obtained. Comparisons are also made of the critical conditions [−Ma_c,a_c,q_ic] between the present results and published data sets for the linear basic temperature profile case, and the agreement is found out to be generally good.