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The assessment of the risk of virus transmission through papers, such as postcards, is important. However, the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) on different types of papers is currently unknown. Investigation of the survival time of these viruses on different types of papers will provide insights into their risk of long-distance transport by postal items. We evaluated the stability of SARS-CoV-2 and IAV, mixed with a culture medium, on the surface of postcards with various coatings, including plain paper (PP), inkjet paper (IP), and inkjet photo paper (IPP). The surface structure of each paper was microscopically assessed. The surface structures of PP, IP, and IPP varied greatly depending on the presence or absence, and type, of coat layer, regardless of the base material. IP and IPP surfaces were less conducive to virus survival than PP surfaces, because of the difference in surface shapes. The survival times of SARS-CoV-2 on each paper were approximately 59.8 (PP), 6.5 (IP), and 9.8 h (IPP), and significantly longer than those of IAV (10.3, 1.8, and 3.3 h, respectively). The risk of SARS-CoV-2 transmission via paper, such as postcards, is significantly higher than that of IAV transmission. While PP, IP, and IPP have the same base material, their surface structures differ, which affects viral stability. The IP and IPP surfaces are less suitable for virus survival. This study provides novel insights into the risks of viral transmission via paper. [ABSTRACT FROM AUTHOR]

In this study, a probabilistic analysis of the critical velocity for an axially moving cracked elastic and isotropic plate is presented. Axially moving materials are commonly used in modelling of manufacturing processes, like paper making and plastic forming. In such systems, the most serious threats to runnability are instability and material fracture, and finding the critical value of velocity is essential for efficiency. In this paper, a formula for the critical velocity is derived under constraints for the probabilities of instability and fracture. The significance of randomness in different model parameters is investigated for parameter ranges typical of paper material and paper machines. The results suggest that the most significant factors are variations in the crack length and tension magnitude. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we report on the microencapsulation of glucose oxidase from Aspergillus niger (GOx) and laccase from Trametes versicolor (TvL) with the goal of immobilizing these enzymes in paper substrates to develop biosensors and bioreactors. Despite having high encapsulation efficiency, the technique caused a severe decrease (up to 65%) in the specific activities of both enzymes once microencapsulated. Encapsulated TvL presented lower K M and V max values compared to free laccase in solution, but the K M for GOx did not change after microencapsulation. TvL was found to interact strongly with poly(ethyleneimine) (PEI) in a manner similar to that expected from an uncompetitive inhibition mechanism, and fluorescence and circular dichroism spectroscopy demonstrated that significant alteration of the enzyme''s conformation occurs in the presence of PEI, an effect of the cationic polymer that was not observed with GOx. Microencapsulation improved the thermal stability of GOx at temperatures up to 60°C due to stabilization of its active conformation but reduced the thermal stability of laccase because of the increased coordination between PEI and copper atoms in the enzyme''s active site. Preliminary GOx bioactive paper was fabricated, which could be potentially used as food packaging paper. [Copyright &y& Elsevier]

Abstract: The instability of the tree-like multicast overlay caused by nodes’ abrupt departures is considered as one of the major problems for peer-to-peer (P2P) multicast systems. In this paper, we present a protocol for improving the overlay’s stability by actively estimating the nodes’ lifetime model, and combining the nodes’ lifetime information with the overlay’s structural properties. We use the shifted Pareto distribution to model the nodes’ lifetimes in designing our protocol. To support this model, we have measured the residual lifetimes of the nodes in a popular IPTV system named PPLive [PPLive. http://www.pplive.com], and have formally analyzed the relationships between the distribution of the nodes’ lifetimes, ages and their residual lifetimes under the shifted Pareto distribution model. We evaluate the overlay construction strategies, which are essential in improving the overlay’s stability in our protocol, by comparing them with a number of other strategies in simulation. The experimental results indicate that our proposed protocol could improve the overlay’s stability considerably, with informative but not necessarily accurate lifetime model estimation, and with limited overhead imposed on the network as well as negligible sacrifice regarding the end-to-end service latencies for the nodes on the overlay. [Copyright &y& Elsevier]

Abstract: In this paper, the notion of loss of sustainability of a mechanical state in a granular assembly is investigated. The vanishing of the second-order work, defined on the macroscopic scale from tensorial variables, is shown to play a fundamental role in detecting the occurrence of this type of bifurcation. Then a link is established between the macroscopic second-order work on the specimen scale and a discrete local expression that introduces microscopic variables defined on each contact scale. This relation opens up a micro-mechanical interpretation allowing one to examine which micro-structural features are responsible for the vanishing of the macroscopic second-order work. Finally, it is established that both geometrical and material micro-structural origins may combine to induce the occurrence of bifurcation on a specimen scale. [Copyright &y& Elsevier]

Abstract: In the present paper, a description and mathematical analysis of a simple model of nonlinear pattern formation is given. The model is based on the so-called activator-inhibitor system proposed by Thomas. We introduce time delay into the reaction term and focus on its influence on morphogenesis and pattern formation. Numerical simulations are presented and compared for both cases without and with delay. [Copyright &y& Elsevier]