Excessive Memory Usage of the ELLPACK Sparse Matrix Storage Scheme throughout the Finite Element Computations

Sparse matrices are occasionally encountered during solution of various problems by means of numerical methods, particularly the finite element method. ELLPACK sparse matrix storage scheme, one of the most widely used methods due to its implementation ease, is investigated in this study. The scheme uses excessive memory due to its definition. For the conventional finite element method, where the node elements are used, the excessive memory caused by redundant entries in the ELLPACK sparse matrix storage scheme becomes negligible for large scale problems. On the other hand, our analyses show that the redundancy is still considerable for the occasions where facet or edge elements have to be used

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

ANALYTIC AND SEMIANALYTIC SOLUTIONS IN ELECTRICAL-IMPEDANCE TOMOGRAPHY .2. 3-DIMENSIONAL PROBLEMS

We give analytic and semi-analytic solutions to a number of problems which are related to the image reconstruction problem of electrical impedance tomography (EIT) in three dimensions

A NEW DESCENT ALGORITHM FOR ELECTRICAL-IMPEDANCE TOMOGRAPHY

In Electrical Impedance Tomography (EIT). the main goal is to reconstruct the conductivity distribution of an object by means of repeated current injection through neighboring electrodes and measuring the resulting voltage differences between the remaining electrodes. Most of the algorithms currently used in EIT reconstruct the conductivity variation after the problem is linearized around a known conductivity distribution. In this new algorithm, variational techniques will be used to obtain a set of equations that must be satisfied by the optimum conductivity distribution, namely the state and adjoint state (or, costate) equations and the expression which is obtained by evaluating the gradient of the cost functional with respect to the conductivity distribution

A METHOD FOR COMPARATIVE-EVALUATION OF EIT ALGORITHMS USING A STANDARD DATA SET

The point spread function (PSF) is the most widely used tool for quantifying the spatial resolution of imaging systems. However, prerequisites for the proper use of this tool are linearity and space invariance. Because EIT is non-linear it is only possible to compare different reconstruction algorithms using a standard data set. In this study, the FEM is used to generate simulation data, which are used to investigate the non-linear behaviour of EIT, the space dependence of its PSF and its capability of resolving nearby objects. It is found that for the case of iterative backprojection (IterB), the full width half maximum (FWHM) values of single-object perturbations for central, intermediate and peripheral high-contrast objects are 27%, 18% and 14% of the imaging region diameter respectively. For the method based on singular value decomposition of the Geselowitz lead sensitivity matrix (GS-SVD), the FWHM is not space dependent and is 12% of the imaging region diameter. Conclusions obtained using single-object PSF studies must also be checked with double-object or more complex perturbations because EIT is non-linear. For example, the GS-SVD method fails to detect two widely separated objects unless the truncation level of SVD is carefully adjusted. With more truncation, however, the resolution of the method is worsened. Based on these and similar observations a set of simulation data, which is proposed for comparative evaluation of different EIT algorithms, is specified and explained in the conclusion section

The prevalence of Behcet's syndrome, familial Mediterranean fever, HLA-B51 and MEFV gene mutations among ethnic Armenians living in Istanbul, Turkey

Objectives: We investigated the prevalence of Behcet's syndrome (BS) among the ethnic Armenians in Istanbul using Familial Mediterranean Fever (FMF) as a comparator disease. We also studied HLA-B51 and MEFV mutations among a group of healthy Armenians and a non-Armenian population