Thermodynamic Analogy for Structural Phase Transitions

We investigate the relationship between ground-state (zero-temperature) quantum phase transitions in systems with variable Hamiltonian parameters and classical (temperature-driven) phase transitions in standard thermodynamics. An analogy is found between (i) phase-transitional distributions of the ground-state related branch points of quantum Hamiltonians in the complex parameter plane and (ii) distributions of zeros of classical partition functions in complex temperatures. Our approach properly describes the first- and second-order quantum phase transitions in the interacting boson model and can be generalized to finite temperatures.Comment: to be published by AIP in Proc. of the Workshop "Nuclei and Mesoscopic Physics" (Michigan State Univ., Oct 2004); 10 pages, 3 figure

Enhanced Model of Nonlinear Spiral High Voltage Divider

This paper deals with the enhanced accurate DC and RF model of nonlinear spiral polysilicon voltage divider. The high resistance polysilicon divider is a sensing part of the high voltage start-up MOSFET transistor that can operate up to 700 V. This paper presents the structure of a proposed model, implemented voltage, frequency and temperature dependency, and scalability. A special attention is paid to the ability of the created model to cover the mismatch and influence of a variation of process parameters on the device characteristics. Finally, the comparison of measured data vs. simulation is presented in order to confirm the model validity and a typical application is demonstrated

The Perception of Governmental Support in The Context of Competitiveness of SMEs in the Czech Republic

Whether or not an entrepreneur develops the enterprise successfully and increases competitiveness depends on many factors. All businesses, however, are inherently connected with the business environment which significantly influences their performance. In this regard, the state is among the most important factors. It also performs many other roles through which it may be either helpful or harmful in the eyes of a business owner, e.g. it determines the legislative framework of entrepreneurship, sets conditions for starting a business and regulates competition. The way the role of the state is perceived by small and medium-sized enterprises was researched in 2015 as a part of a project at Tomas Bata University in Zlín. The research analysed data from 1,141 respondents from all regions of the Czech Republic and included, among others, the question of the state’s role in the business environment. The presented paper covers three selected areas of the state’s influence on the business environment: creating favourable conditions for the business environment, governmental financial support of entrepreneurs, and administrative burden on entrepreneurs. These areas were also examined with the emphasis on the analysis of differences between the perception of entrepreneurs from different industries and entrepreneurs with different sizes of their businesses. It was revealed that entrepreneurs were very critical to the state’s role in the business environment; in particular, 60% of respondents disagree with the fact that the state creates favourable conditions for business in the Czech Republic. It was proved that the line of business of enterprises correlates with perception of the state’s role within the business environment. The research into perception of a governmental financial support was proved to be dependent on a company size which may signal the support of certain company sizes and influencing their competitiveness

Toll-like receptor signaling in thymic epithelium controls monocyte-derived dendritic cell recruitment and Treg generation

The development of thymic regulatory T cells (Treg) is mediated by Aire-regulated self-antigen presentation on medullary thymic epithelial cells (mTECs) and dendritic cells (DCs), but the cooperation between these cells is still poorly understood. Here we show that signaling through Toll-like receptors (TLR) expressed on mTECs regulates the production of specific chemokines and other genes associated with post-Aire mTEC development. Using single-cell RNA-sequencing, we identify a new thymic CD14(+)Sirp alpha (+) population of monocyte-derived dendritic cells (CD14(+)moDC) that are enriched in the thymic medulla and effectively acquire mTEC-derived antigens in response to the above chemokines. Consistently, the cellularity of CD14(+)moDC is diminished in mice with MyD88-deficient TECs, in which the frequency and functionality of thymic CD25(+)Foxp3(+) Tregs are decreased, leading to aggravated mouse experimental colitis. Thus, our findings describe a TLR-dependent function of mTECs for the recruitment of CD14(+)moDC, the generation of Tregs, and thereby the establishment of central tolerance. Immune tolerance is mediated by the deletion of autoreactive T cells via medullary thymic epithelial cells (mTEC) and dendritic cells (DC), and by the induction of regulatory T cells (Treg). Here the authors show that mTEC receiving toll-like receptor signaling control the recruitment of CD14(+)Sirp alpha (+) DC population that is capable of inducing Treg for establishing tolerance

Electrocatalytic Assay for Monitoring Methylglyoxal-Mediated Protein Glycation

Protein glycation is a complex process that plays an important role in diabetes mellitus, aging, and the regulation of protein function in general. As a result, current methodological research on proteins is focused on the development of novel approaches for investigating glycation and the possibility of monitoring its modulation and selective inhibition. In this paper, a first sensing strategy for protein glycation is proposed, based on protein electroactivity measurement. Concretely, the label-free method proposed is based on the application of a constant-current chronopotentiometric stripping (CPS) analysis at Hg-containing electrodes. The glycation process was monitored as the decrease in the electrocatalytic protein signal, peak H, observed at highly negative potentials at around −1.8 V (vs Ag/AgCl_3 M KCl), which was previously ascribed to a catalytic hydrogen evolution reaction (CHER). Using this method, a model protein bovine serum albumin was investigated over 3 days of incubation with the glycation agent methylglyoxal in the absence or presence of the glycation inhibitor aminoguanidine (pimagedine). The electrochemical methodology presented here could open up new possibilities in research on protein glycation and oxidative modification. The methodology developed also provides a new option for the analysis of protein intermolecular interactions using electrochemical sensors, which was demonstrated by the application of a silver solid amalgam electrode (AgSAE) for monitoring the glycation process in samples of bovine serum albumin, human serum albumin, and lysozyme

A novel conditional Aire allele enables cell-specific ablation of the immune tolerance regulator Aire

Medullary thymic epithelial cell (mTEC)-restricted expression of autoimmune regulator (Aire) is essential for establishment of immune tolerance. Recently, Aire was also shown to be expressed in cells of hematopietic and reproductive lineages. Thus, the generation of Aire(fl/fl) mouse strain enables the investigation of the cell-specific function of Aire

NKD1 marks intestinal and liver tumors linked to aberrant Wnt signaling

AbstractThe activity of the Wnt pathway undergoes complex regulation to ensure proper functioning of this principal signaling mechanism during development of adult tissues. The regulation may occur at several levels and includes both positive and negative feedback loops. In the present study we employed one of such negative feedback regulators, naked cuticle homolog 1 (Nkd1), to follow the Wnt pathway activity in the intestine and liver and in neoplasia originated in these organs. Using lineage tracing in transgenic mice we localized Nkd1 mRNA to the bottom parts of the small intestinal crypts and hepatocytes surrounding the central vein of the hepatic lobule. Furthermore, in two mouse models of intestinal tumorigenesis, Nkd1 expression levels were elevated in tumors when compared to healthy tissue. We utilized a collection of human intestinal polyps and carcinomas to confirm that NKD1 represents a robust marker of neoplastic growth. In addition, expression analysis of NKD1 in liver cancer showed that high expression levels of the gene distinguish a subclass of hepatocellular carcinomas related to aberrant Wnt signaling. Finally, our results were confirmed by bioinformatic analysis of large publicly available datasets that included gene expression profiling and high-throughput sequencing data of human colon and liver cancer specimens