A Review on the epidemiology and characteristics of COVID-19

In December 2019, there was a health emergency worldwide named novel coronavirus or COVID-19 by the world health organization (WHO). It originated from the Wuhan seafood market, Hubei Province, China. Till now Severe Acute Respiratory Syndrome Coronavirus-2 or SARS-CoV-2 spread over 216 countries with 177,108,695 confirmed cases and 3,840,223 confirmed death cases has been reported (5:31 pm CEST, 18 June 2021; WHO). Analyzing the risk factor of this pandemic situation, different government health organizations of all the countries including WHO are taking several preventive measures with ongoing research works, even the vaccination process started. In this study, we tried to analyze all the available information on pandemic COVID-19, which includes the origin of COVID-19, pathogenic mechanism, transmission, diagnosis, treatment, and control-preventive measures, also the additional treatment and prevention taken by the Indian government is being studied here

Cell-Laden alginate biomaterial modelling using three-dimensional (3D) microscale finite element technique

A novel modelling technique using finite element analysis to mimic the mechanoresponse of cell-laden biomaterial is proposed for the use in bioinks and other tissue engineering applications. Here a hydrogel-based composite biomaterial specimen was used consisting of 5% (V/V) HeLa cells added to alginate solution (4% W/V) and another specimen with no living cell present in alginate solution (4% W/V). Tensile test experiments were performed on both the specimens with a load cell of 25 N. The specimens were bioprinted using an in-house developed three-dimensional (3D) bioprinter. To allow for the nonlinear hyperelastic behavior of the specimen, the specimens were loaded very slowly, at rates of 0.1 mm/min and 0.5 mm/min, during the tensile test. The microscale finite element models developed in Ansys were loaded with similar load rates and their responses were recorded. Both the model results were validated with the experiment results. A very good agreement between the finite element model and the tensile test experiment was observed under the same mechanical stimuli. Hence, the study reveals that bioprinted scaffold can be virtually modeled to obtain its mechanical characteristics beforehand.Comment: 4 pages, 7 figure

A finite element analysis model to predict and optimize the mechanical behaviour of bioprinted scaffolds

Bioprinting is an enabling biofabrication technique to create heterogeneous tissue constructs according to patient-specific geometries and compositions. Optimization of bioinks as per requirements for specific tissue applications is a critical exercise in ensuring clinical translation of the bioprinting technologies. Most notably, optimum hydrogel polymer concentrations are required to ensure adequate mechanical properties of bioprinted constructs without causing significant shear stresses on cells. However, experimental iterations are often tedious for optimizing the bioink properties. In this work, a finite element modelling approach has been undertaken to determine the effect of different bioink parameters like composition, concentration on the range of stresses being experienced by the cells in a bioprinting process. The stress distribution of the cells at different parts of the constructs has also been modelled. It is found that both bioink chemical compositions and stoichiometric concentrations can substantially alter the stress effects experienced by the cells. Similarly, concentrated regions of soft cells near the pore regions were found to increase stress concentrations by almost three times compared to the Von-Mises stress generated around the region of cells away from the pores. The study outlines the importance of finite element models in the rapid development of bioinks.Comment: 21 pages, 10 figure

An artificial neural network approach for short-term wind speed forecast

Master of ScienceDepartment of Electrical and Computer EngineeringAnil PahwaElectricity generation capacity from different renewable sources has been significantly growing worldwide in recent years, specially wind power. Fast dispatch of wind power provides flexibility for spinning reserve. However, wind is intermittent in nature. Thus, stable grid operations and energy management are becoming more challenging with the increasing penetration of wind in power systems. Efficient forecast methods can help the scenario. Many wind forecast models have been developed over the years. Highly effective models with the combination of numerical weather prediction and statistical models also exist at present. This study intends to develop a model to forecast hourly wind speed using an artificial neural network (ANN) approach for effective and fast operation with minimum data. The procedure is outlined in this work and the performance of the ANN model is compared with the persistence forecast model

Virtual Topology Reconfiguration Issues in Evolution of WDM Optical Networks

We consider the reconfiguration problem in multi-fiber WDM optical networks. In a real-time network as the traffic evolves with time: the virtual topology may not remain optimal for the evolving traffic, leading to a degradation of network performance. However, adapting the virtual topology to the changing traffic may lead to service disruption. This optimization problem hence captures the trade-off between network performance and number of reconfigurations applied to the virtual topology. The above problem is solved through a Mixed Integer Linear Programming formulation with a multivariate objective function, that captures both these parameters. However the problem is NP-hard and such an approach is unable to solve large problem instances in a reasonable time. In this paper, we also propose a simulated annealing based heuristic algorithm for solving problems of higher complexity. We compare the performance and the computation time of the MILP model and the heuristic algorithm considering different tests instances. Our results indicate that simulated annealing obtains results within 5% of the optimal solution, thus making it a viable approach in large scale networks

Diverse routing for shared risk resource groups (SRRG) failures in WDM optical networks

Failure resilience is one of the desired features of the Internet. Most of the traditional restoration architectures are based on single-failure assumption which is unrealistic. Multiple link failure models, in the form of shared-risk link groups (SRLG\u27s) and shared risk node groups (SRNG\u27s) are becoming critical in survivable optical network design. We classify both these form of failures under a common heading of shared-risk resource groups (SRRG) failures. In our research, we propose graph transformation techniques for tolerating multiple failures arising out of shared resource group (SRRG) failures. Diverse routing in such multi-failure scenario essentially necessitates finding out two paths between a source and a destination that are SRRG disjoint. The generalized diverse routing problem has been proved to be NP-complete. The proposed transformation techniques however provide a polynomial time solution for certain restrictive failure sets. We study how restorability can be achieved for dependent or shared risk link failures and multiple node failures and prove the validity of our approach for different network scenarios

3D bioprinting for reconstituting the cancer microenvironment.

The cancer microenvironment is known for its complexity, both in its content as well as its dynamic nature, which is difficult to study using two-dimensional (2D) cell culture models. Several advances in tissue engineering have allowed more physiologically relevant three-dimensional (3D) in vitro cancer models, such as spheroid cultures, biopolymer scaffolds, and cancer-on-a-chip devices. Although these models serve as powerful tools for dissecting the roles of various biochemical and biophysical cues in carcinoma initiation and progression, they lack the ability to control the organization of multiple cell types in a complex dynamic 3D architecture. By virtue of its ability to precisely define perfusable networks and position of various cell types in a high-throughput manner, 3D bioprinting has the potential to more closely recapitulate the cancer microenvironment, relative to current methods. In this review, we discuss the applications of 3D bioprinting in mimicking cancer microenvironment, their use in immunotherapy as prescreening tools, and overview of current bioprinted cancer models

Sub-graph routing : a novel fault-tolerant architecture for shared-risk link group failures in WDM optical networks

Failure resilience is one the desired features of the Internet. Multiple link failure models, in the form of shared-risk link group (SRLG) failures, are becoming critical in survivable optical network design. Most of the traditional restoration schemes are based on the single-failure assumption which is unrealistic. In our research, we propose a novel survivability approach that can tolerate multiple failures arising out of SRLG situations. Each network has a set of sub-graphs that can be created by removing each of the links in the network and, in addition, removing all of the links of a SRLG. Connections in the newly proposed strategy are accepted if they can be routed in all the sub-graphs, and are protected against all single link and SRLG failures. We also study how restorability can be achieved for node failures and analyze the performance of our approaches for different network topologies. Our proposed restoration architecture requires the storage of network state information corresponding to each of the possible failure scenarios defined by the subgraphs. This restoration model is novel and can be implemented in current WDM backbone networks

Evaluating dual-failure restorability in mesh-restorable WDM optical networks

Double link failure models, in which any two links in the network fail in an arbitrary order, are becoming critical in survivable optical network design. A significant finding is that designs offering complete dual-failure restorability require almost triple the amount of spare capacity. In this paper, networks are designed to achieve 100% restorability under single link failures, while maximizing coverage against any second link failure in the network. In the event of a single link failure, the restoration model attempts to dynamically find a second alternate link-disjoint end-to-end path to provide coverage against a sequential overlapping link failure. Sub-graph routing (M. T. Frederick et al., Feb. 2003) is extended to provide dual-failure restorability for a network provisioned to tolerate all single-link failures. This strategy is compared with shared-mesh protection. The results indicate that sub-graph routing can achieve overlapping second link failure restorability for 95-99% of connections. It is also observed that sub-graph routing can inherently provide complete dual-failure coverage for ~72-81% of the connections