Sensitivity analysis for frictional contact problems in the augmented Lagrangian formulation

Direct differentiation method of sensitivity analysis is developed for frictional contact problems. As a result of the augmented Lagrangian treatment of contact constraints, the direct problem is solved simultaneously for the displacements and Lagrange multipliers using the Newton method. The main purpose of the paper is to show that this formulation of the augmented Lagrangian method is particularly suitable for sensitivity analysis because the direct differentiation method leads to a non-iterative exact sensitivity problem to be solved at each time increment. The approach is applied to a general class of three-dimensional frictional contact problems, and numerical examples are provided involving large deformations, multibody contact interactions, and contact smoothing techniques.     

BDDC by a frontal solver and the stress computation in a hip joint replacement

A parallel implementation of the Balancing Domain Decomposition based on Constraints (BDDC) method using the frontal solver is employed to solve systems of linear equations from finite element analysis, and incorporated into a standard finite element system for engineering analysis by linear elasticity. Results of computation of stress in a hip replacement are presented. The part is made of titanium and loaded by the weight of human body. The performance of BDDC with added constraints by averages and with added corners is compared.     

Assessment of the potential natural status of riparian zones in the Czech Republic

Riparian zones represent an important ecosystem providing a range of functions and services important to humans—for example, biodiversity support, a reduction in erosion risk, or the transport of pollutants from the surrounding landscape to watercourses. At the same time, it is an environment that has been often subjected to significant pressure during the agricultural cultivation of the landscape or the development of industrial and residential activities of human society. Thus, a large number of riparian ecosystems have been disappeared or degraded. The assessment of the overall ecological status of riparian habitats constitutes an important source of information for watercourse management and landscape planning, the aim of which should be to maintain good status or to improve the current unsatisfactory state of these habitats. However, in order to reliably evaluate the current ecological status of the landscape, it is necessary to have information on the reference status, that is, a potentially natural status that would prevail without human influence. For this purpose, a methodology that can determine the potential natural status of riparian zones for Central European conditions was developed. In this study, it was found that approximately a quarter (26%) of all river basins in the Czech Republic reach very low environmental values of the potential natural status of riparian zones and, conversely, approximately 29% of river basins are expected to develop significantly above average riparian zone quality.     

The Good,the Bad,and the Commons: A Critical Review of Popular Discourse on Piracy and Power During Anti‐ACTA Protests

The article analyses popular discourse on piracy and power that emerged as a result of people's online anti‐ACTA (Anti‐Counterfeiting Trade Agreement) engagement in Poland. Drawing upon a social semiotic visual analysis of 921 ACTA‐related images shared online in 2012, the author analyzes a collective reconstruction of the concept of “piracy” and the popular narrative of the conflict in terms of its sides and subject. The study reveals how anti‐ACTA images form a medium of national popular culture adaptation of global pop‐ and countercultural modalities. The protesters appropriated them to oppose another attempt at global copyright enforcement. New media became not only the tool and environment for these activities but were also collectively depicted as “the commons,” endangered by the agreement.     

Novel Approach to Tooth Chemistry: Quantification of Human Enamel Apatite in Context for New Biomaterials and Nanomaterials Development

A series of linear profiles of the elements of the enamel in human molar teeth were made with the use of an electron microprobe and a Raman microscope. It is postulated that the enamel can be treated as the superposition of variable “overbuilt” enamel on the stable “core” enamel at the macro-, micro- and nanoscale level. The excessive values characterize the “overbuilt enamel”. All the profiles of excessive parameters along the enamel thickness from the enamel surface to the dentin enamel junction (DEJ) can be approximated very precisely with the use of exponential functions, where Ca, P, Cl and F spatial profiles are decaying while Mg, Na, K and CO₃²⁻ ones are growing distributions. The “overbuilt” apatite formed on the boundary with DEJ, enriched in Na, Mg, OH and carbonates, reacts continuously with Ca, Cl and F, passing into an acid-resistant form of the “overbuilt” enamel. The apparent phases arriving in boundary regions of the “overbuilt enamel” were proposed. Microdiffraction measurements reveal relative variation of energy levels during enamel transformations. Our investigations are the milestones for a further new class of biomaterial and nanomaterial development for biomedical applications.     

β-Actin Peptide-Based Inhibitors of Histidine Methyltransferase SETD3

SETD3 was recently identified as the histidine methyltransferase responsible for N³-methylation of His73 of β-actin in humans. Overexpression of SETD3 is associated with several diseases, including breast cancer. Here, we report a development of actin-based peptidomimetics as inhibitors of recombinantly expressed human SETD3. Substitution of His73 by simple natural and unnatural amino acids led to selected β-actin peptides with high potency against SETD3 in MALDI-TOF MS assays. The selenomethionine-containing β-actin peptide was found to be the most potent SETD3 inhibitor (IC₅₀=161 nM). Supporting our inhibition assays, a combination of computational docking and molecular dynamics simulations revealed that the His73 binding pocket for β-actin in SETD3 is rigid and accommodates the inhibitor peptides with similar binding modes. Collectively, our work demonstrates that actin-based peptidomimetics can act as potent SETD3 inhibitors and provide a basis for further development of highly potent and selective inhibitors of SETD3.     

Differences in lipid parameters among statins treated patients with coronary arteriosclerosis – a pilot study

LDL, total cholesterol (TC), high‐density lipoprotein (HDL) are poor predictors of the cardiovascular risk among patients undergoing hypolipidaemic therapy with statins. Thus, in this pilot study we have attempted to determine, on the basis of routinely used assessments of lipid profiles, sensitive and inexpensive parameter which would associate with the severity of coronary artery disease in patients undergoing hypolipidaemic treatment who achieved LDL goal. Apolipoprotein (apo) B100, apoA1, LDL, triglycerides, HDL, lipoprotein (a) and TC levels were assessed in 140 patients referred for coronary angiography. The various ratios based on lipid parameters were calculated and compared to patients taking statins. Coronary arteriosclerosis was determined by the degree of single stenosis and quantitatively by applying the Gensini score. Uing multivariate analysis we have found that in the group with hypolipidaemic therapy and/or with treatment LDL target (70–100 mg/dL) the TC/apoB100 ratio was associated with coronary artery stenosis. Additionally, univariate analysis showed that the TC/apoB100 ratio (among treated subjects) was significantly lower in patients with haemodynamically significant stenosis of coronary arteries than in matched patients without coronary artery lesions.     

Measuring transient temperature of the medium in power engineering machines and installations

Under steady-state conditions when fluid temperature is constant, there is no damping and time lag and temperature measurement can be made with high accuracy. But when fluid temperature is varying rapidly as during start-up, quite appreciable differences occur between the true temperature and the measured temperature because of the time required for the transfer of heat to the thermocouple placed inside a heavy thermometer pocket. In this paper, two different techniques for determining transient fluid temperature based on the first and second order thermometer model are presented. The fluid temperature was determined using measured thermometer temperature, which is suddenly immersed into boiling water. To demonstrate the applicability of the presented method to actual data, the air temperature which changes in time, was calculated based on the temperature readings from the sheathed thermocouple.     

The Efficacy of Black Chokeberry Fruits against Cardiovascular Diseases

Epidemiological studies have emphasized the association between a diet rich in fruits and vegetables and a lower frequency of occurrence of inflammatory-related disorders. Black chokeberry (Aronia melanocarpa L.) is a valuable source of biologically active compounds that have been widely investigated for their role in health promotion and cardiovascular disease prevention. Many in vitro and in vivo studies have demonstrated that consumption of these fruits is associated with significant improvements in hypertension, LDL oxidation, lipid peroxidation, total plasma antioxidant capacity and dyslipidemia. The mechanisms for these beneficial effects include upregulation of endothelial nitric oxide synthase, decreased oxidative stress, and inhibition of inflammatory gene expression. Collected findings support the recommendation of such berries as an essential fruit group in a heart-healthy diet. The aim of this review was to summarize the reports on the impact of black chokeberry fruits and extracts against several cardiovascular diseases, e.g., hyperlipidemia, hypercholesterolemia, hypertension, as well as to provide an analysis of the antioxidant and anti-inflammatory effect of these fruits in the abovementioned disorders.