Search results for "Minimum"
showing 10 items of 327 documents
Fluoroquinolone–metal complexes: A route to counteract bacterial resistance?
2014
Abstract Microbial resistance to antibiotics is one of the biggest public health threats of the modern world. Antibiotic resistance is an area of much clinical relevance and therefore research that has the potential to identify agents that may circumvent it or treat resistant infections is paramount. Solution behavior of various fluoroquinolone (FQ) complexes with copper(II) in the presence and absence of 1,10-phenanthroline (phen) was studied in aqueous solution, by potentiometry and/or spectrophotometry, and are herein described. The results obtained showed that under physiological conditions (micromolar concentration range and pH 7.4) only copper(II):FQ:phen ternary complexes are stable.…
Multiscale Simulations of SARS-CoV-2 3CL Protease Inhibition with Aldehyde Derivatives. Role of Protein and Inhibitor Conformational Changes in the R…
2021
We here investigate the mechanism of SARS-CoV-2 3CL protease inhibition by one of the most promising families of inhibitors, those containing an aldehyde group as a warhead. These compounds are covalent inhibitors that inactivate the protease, forming a stable hemithioacetal complex. Inhibitor 11a is a potent inhibitor that has been already tested in vitro and in animals. Using a combination of classical and QM/MM simulations, we determined the binding mode of the inhibitor into the active site and the preferred rotameric state of the catalytic histidine. In the noncovalent complex, the aldehyde group is accommodated into the oxyanion hole formed by the NH main-chain groups of residues 143 …
Informational rigidity in mesitylene-based calix[4]arenes adopting a 1,3-alternate conformation
2000
Abstract Two chiral derivatives of a mesitylene-based calix[4]arene known to exist in the 1,3-alternate conformation were prepared by the attachment of homochiral residues to the four exo -hydroxy groups. Thus, the enantiotopic protons of the central scaffold became diastereotopic, leading to a doubling of their 1 H NMR signals in one example. From the temperature independence of the NMR spectrum, a lower limit of 24.2 kcal/mol could be estimated for the barrier of ring inversion. MM3 calculations confirm the 1,3-alternate conformation as the energy minimum, and estimate a barrier of 25.7 kcal/mol for the 1,3-alternate-to-1,3-alternate* interconversion process. This high barrier is due to t…
Latvia: Both Sides of the Economic Recovery Success Story
2016
Latvian social policy is close to the neoliberal model of the welfare state based on macroeconomic indicators of low welfare state spending, high income inequality, low minimum wage and low degree of decommodification. Latvia was among the first countries to be stung by the crisis in 2008. Key words became: austerity, fiscal consolidation and structural adjustment measures. A minimum social safety network was introduced to improve targeted social support. Funding from the European Social Fund was instrumental in mitigating unemployment, facilitating a large temporary works programme. Latvia joined the Euro zone in 2014 and is quite successfully returning loans. Such is one side of the succe…
Late decaying 2-component dark matter scenario as an explanation of the AMS-02 positron excess
2016
The long standing anomaly in the positron flux as measured by the PAMELA and AMS-02 experiments could potentially be explained by dark matter (DM) annihilations. This scenario typically requires a large "boost factor" to be consistent with a thermal relic dark matter candidate produced via freeze-out. However, such an explanation is disfavored by constraints from CMB observations on energy deposition during the epoch of recombination. We discuss a scenario called late-decaying two-component dark matter (LD2DM), where the entire DM consists of two semi-degenerate species. Within this framework, the heavier species is produced as a thermal relic in the early universe and decays to the lighter…
Definition and Performance Evaluation of a Robust SVM Based Fall Detection Solution
2012
We propose an automatic approach to detect falls in home environment. A Support Vector Machine based classifier is fed by a set of selected features extracted from human body silhouette tracking. The classifier is followed by filtering operations taking into account the temporal nature of a video. The features are based on height and width of human body bounding box, the user's trajectory with her/his orientation, Projection Histograms and moments of order 0, 1 and 2. We study several combinations of usual transformations of the features (Fourier Transform, Wavelet transform, first and second derivatives), and we show experimentally that it is possible to achieve high performance using a si…
A surface hopping algorithm for nonadiabatic minimum energy path calculations
2015
The article introduces a robust algorithm for the computation of minimum energy paths transiting along regions of near-to or degeneracy of adiabatic states. The method facilitates studies of excited state reactivity involving weakly avoided crossings and conical intersections. Based on the analysis of the change in the multiconfigurational wave function the algorithm takes the decision whether the optimization should continue following the same electronic state or switch to a different state. This algorithm helps to overcome convergence difficulties near degeneracies. The implementation in the MOLCAS quantum chemistry package is discussed. To demonstrate the utility of the proposed procedur…
Combining Defocus and Photoconsistency for Depth Map Estimation in 3D Integral Imaging
2017
This paper presents the application of a depth estimation method for scenes acquired using a Synthetic Aperture Integral Imaging (SAII) technique. SAII is an autostereoscopic technique consisting of an array of cameras that acquires images from different perspectives. The depth estimation method combines a defocus and a correspondence measure. This approach obtains consistent results and shows noticeable improvement in the depth estimation as compared to a minimum variance minimisation strategy, also tested in our scenes. Further improvements are obtained for both methods when they are fed into a regularisation approach that takes into account the depth in the spatial neighbourhood of a pix…
Hybrid robust and fast algorithm for three-dimensional phase unwrapping
2009
We present a hybrid three-dimensional (3D) unwrapping algorithm that combines the strengths of two other fast and robust existing techniques. In particular, a branch-cut surface algorithm and a path-following method have been integrated in a symbiotic way, still keeping execution times within a range that permits their use in real-time applications that need a relatively fast solution to the problem. First, branch-cut surfaces are calculated, disregarding partial residue loops that end at the boundary of the 3D phase volume. These partial loops are then used to define a quality for each image voxel. Finally, unwrapping proceeds along a path determined by a minimum spanning tree (MST). The M…
Clustering-based robust three-dimensional phase unwrapping algorithm
2010
Relatively recent techniques that produce phase volumes have motivated the study of three-dimensional (3D) unwrapping algorithms that inherently incorporate the third dimension into the process. We propose a novel 3D unwrapping algorithm that can be considered to be a generalization of the minimum spanning tree (MST) approach. The technique combines characteristics of some of the most robust existing methods: it uses a quality map to guide the unwrapping process, a region growing mechanism to progressively unwrap the signal, and also cut surfaces to avoid error propagation. The approach has been evaluated in the context of noncontact measurement of dynamic objects, suggesting a better perfo…