A ferritic/martensitic (f/m) steel with 9 and 3 mass% of chromium (Cr) and silicon (Si), respectively, was tested on performance in flowing lead–bismuth eutectic (LBE) at 450 and 550 °C, each at ...concentrations of solved oxygen of both 10−7 and 10−6 mass%. The 9Cr–3Si steel generally exhibits the same basic corrosion modes as other f/m materials with 9 mass% Cr and typically lower Si content, namely Steel T91. The Si-rich steel shows an overall improved performance in comparison to T91 at 450 °C and 10−7 mass% solved oxygen, but especially at 450 °C and 10−6 mass% solved oxygen. The advantage of higher Si-content in 9Cr steel is less clear at 550 °C. Especially high oxygen content in flowing LBE at 550 °C, between >10−6 mass% and oxygen saturation, seems detrimental for the high-Si material in respect of the initiation and progress of a solution-based corrosion.
•9Cr–3Si steel shows basically the same phenomena as 9Cr steels with typically lower Si content.•Improved performance in comparison to T91 especially at 450 °C and 10−6 mass% oxygen in LBE.•Less clear benefits from Si addition to 9Cr steel at 550 °C.•Oxygen >10−6 mass% seems detrimental for 9Cr–3Si at 550 °C in respect of solution-based corrosion.
A ferritic/martensitic (f/m) steel with 9 and 3 mass% of chromium (Cr) and silicon (Si), respectively, was tested on performance in flowing lead-bismuth eutectic (LBE) at 450 and 550 degree C, each ...at concentrations of solved oxygen of both 10 super(-7) and 10 super(-6) mass%. The 9Cr-3Si steel generally exhibits the same basic corrosion modes as other f/m materials with 9 mass% Cr and typically lower Si content, namely Steel T91. The Si-rich steel shows an overall improved performance in comparison to T91 at 450 degree C and 10 super(-7) mass% solved oxygen, but especially at 450 degree C and 10 super(-6) mass% solved oxygen. The advantage of higher Si-content in 9Cr steel is less clear at 550 degree C. Especially high oxygen content in flowing LBE at 550 degree C, between >10 super(-6) mass% and oxygen saturation, seems detrimental for the high-Si material in respect of the initiation and progress of a solution-based corrosion.
•Four surfaced exposed and negatively charged amino acid residues in the N-terminal domain of STAT1 are engaged in the release of tyrosine-phosphorylated tetramers from DNA.•Despite elevated ...tyrosine-phosphorylation and prolonged nuclear accumulation upon stimulation of cells with IFNγ, the transcriptional consequences of STAT1 N-terminal gain-of-function mutants affect gene expression not globally, but in a promoter-specific manner.•The STAT1 N-domain is involved in the termination of IFNγ-mediated signal transduction by disrupting higher-order oligomers on DNA.•Our findings reveal a new mechanistic insight into how protein-DNA interactions regulate STAT1-mediated target gene recognition.
Defective cooperative DNA binding of STAT1 (signal transducer and activator of transcription 1) transcription factor has impact on interferon-γ(IFNγ)-regulated transcriptional responses. In this study, we generated N-terminal gain-of-function mutants of this protein which exhibited hyperactive cooperativity and assessed their functional consequences on gene expression. Our data show that four negatively charged, surface-exposed amino acid residues in the N-terminal domain dimer are engaged in the disassembly of tyrosine-phosphorylated tetrameric complexes on DNA and prevent the occurrence of higher-order STAT1 oligomers on low-affinity DNA binding sites. Owing to their improved tetramer stability, the N-terminal mutants showed relaxed sequence requirements for the binding to DNA as compared to the wild-type protein. Similarly to a STAT1 mutant with impaired tetramerization, the N-terminal gain-of-function mutants showed elevated tyrosine-phosphorylation levels and prolonged nuclear accumulation upon stimulation of cells with IFNγ. However, in contrast to the global impairment of IFNγ signalling in tetramerization-deficient mutants, the transcriptional consequences of the N-terminal gain-of-function mutants are rather distinct and affect gene expression locally in a promoter-specific manner. Thus, we conclude that the STAT1 N-domain acts as a double-edged sword: while one interface is crucial for the formation of tetrameric complexes on IFNγ-regulated promoters, the opposite interface harbours an inhibitory mechanism that limits the accumulation of higher-order oligomers simply by disrupting cooperative DNA binding.
In interferon-γ-stimulated cells, the dimeric transcription factor STAT1 (signal transducer and activator of transcription 1) recognizes semi-palindromic motifs in the promoter regions of ...cytokine-driven target genes termed GAS (gamma-activated sites). However, the molecular steps that facilitate GAS binding and the subsequent liberation of STAT1 homodimers from these promoter elements are not well understood.
Using a mutational approach, we identified two critical glutamyl residues within the DNA-binding domain adjacent to the phosphodiester backbone of DNA which efficiently release phospho-STAT1 from DNA. The release of STAT1 dimers from DNA enhances transcriptional activity on both interferon-driven reporter and endogenous target genes. A substitution of either of the two glutamic acid residues broadens the repertoire of putative binding sites on DNA and enhances binding affinity to GAS sites. However, despite elevated levels of tyrosine phosphorylation and a prolonged nuclear accumulation period, the STAT1 DNA-binding mutants show a significantly reduced transcriptional activity upon stimulation of cells with interferon-γ. This reduced transcriptional response may be explained by the deposition of oligomerized STAT1 molecules outside GAS sites.
Thus, two negatively charged amino acid residues in the DNA-binding domain are engaged in the liberation of STAT1 from DNA, resulting in a high dissociation rate from non-GAS sites as a key feature of STAT1 signal transduction, which positively regulates cytokine-dependent gene expression probably by preventing retention at transcriptionally inert sites.
This paper aims to determine how clothing brands affect children’s peer relations. The study was carried out by surveying 145 students. The results indicate that children are familiar with different ...clothing brands but they prefer sports brands. Brands were not the most important decision factor in purchasing process. The brands like decision factor were more important for older children and boys. Older children are also more often associated possession of (non) appropriate clothing brands with negative responses from other children. The children who were afraid of ridiculing of another children also felt more self-confident wearing popular brands of clothing.
This paper aims to determine how clothing brands affect children’s peer relations. The study
was carried out by surveying 145 students. The results indicate that children are familiar with
different ...clothing brands but they prefer sports brands. Brands were not the most important decision
factor in purchasing process. The brands like decision factor were more important for older
children and boys. Older children are also more often associated possession of (non) appropriate
clothing brands with negative responses from other children. The children who were afraid of
ridiculing of another children also felt more self-confident wearing popular brands of clothing.
Zivilcourage und Zensur Koch, Verena
DramArt : revistă de studii teatrale = Zeitschrift für Theaterstudien = Journal of theatre studies,
2018
7
Journal Article
Odprti dostop
This paper is related to my job with my search to find workable strategies for my students to be inspired and encouraged. In this case it is the surviving of moral courage in times of ...de-democratizition and sneaking secret censorship. By giving examples through history I try to ilustrate my own position towards civil courage in society and especially in theatre.
Uvod: Opravljena je bila analiza pojavljanja dejavnikov tveganja nezdravega načina prehranjevanja med odraslimi prebivalci Slovenije glede na biološke in sociodemografske spremenljivke.
A series of ring-expanded (“fat”) heterocycles, nucleoside and nucleotide analogues (RENs) containing the imidazo4,5-e1,3diazepine ring system (9, 14, 15, 18, 24-26, 28, 31, and 33) and ...imidazo4,5-e1,2,4triazepine ring systems (30b, 30c, 32, and 34), have been synthesized as potential inhibitors of NTPases/helicases of Flaviviridae, including the West Nile virus (WNV), hepatitis C virus (HCV), and Japanese encephalitis virus (JEV). An amino-terminal truncated form of human enzyme Suv3( Δ 1 - 159) was also included in the study so as to assess the selectivity of RENs against the viral enzymes. The analogues of RENs included structural variations at position 1 of the heterocyclic base and contained changes in both the type of sugar moieties (ribo, 2‘-deoxyribo, and acyclic sugars) and the mode of attachment (α versus β anomeric configuration) of those sugars to the heterocyclic base. The target RENs were biochemically screened separately against the helicase and ATPase activities of the viral NTPases/helicases. A number of RENs inhibited the viral helicase activity with IC50 values that ranged in micromolar concentrations and exhibited differential selectivity between the viral enzymes. In view of the observed tight complex between some nucleosides and RNA and/or DNA substrates of a helicase, the mechanism of action of RENs might involve their interaction with the appropriate substrate through binding to the major or minor groove of the double helix. The REN-5‘-triphosphates, on the other hand, did not influence the above unwinding reaction, but instead exerted the inhibitory effect on the ATPase activity of the enzymes. The activity was found to be highly dependent upon the low concentration levels of the substrate ATP. At concentrations >500 μM of RENs and the ATP concentrations >10 times the K m value of the enzyme, a significant activation of NTPase activity was observed. This activating effect underwent further dramatic enhancement (>1000%) by further increases in ATP concentration in the reaction mixture. A tentative mechanistic model has been proposed to explain the observed results, which includes an additional allosteric binding site on the viral NTPases/helicases that can be occupied by nucleoside/nucleotide-type molecules such as RENs.
The purpose of this study was to examine the integration of natural sciences and mathematics into home economics teaching, particularly any factors hindering integration. Altogether 88 Slovenian home ...economics teachers were questioned. The results show that biology, consumer and health education were integrated into home economics courses more often than other subjects. Slovenian home economics teachers’ integration of other school subjects or topics depends mainly on their work experience and combination of subjects during their undergraduate studies. Another indicator, a negative one, was that our teachers didn’t know some relevant science and mathematics subject curricula and they are not enough competent in these sciences. This should be the first step in the future development of home economics teacher education.
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