Semiempirical Studies of Inner-Core Energy Levels. Part 7. ESCA Shifts of Germanium in Molecular Systems

Shifts of the 3p213 ene;.·gy levels of germanium in different chemical moieties were studied by using the semiempirical SCC-MO method. The calculations were performed within the framework of the electrostatic potential method in the point-charge approximation. Relaxation energies were explicitly taken into account by employing the equivalent core and transition potential methods. It was found out that the relaxation energy plays a decisive role in determining shifts along the series GeH4--+ Ge(CHak The results obtained by the equivalent core and transition potential methods are similar being in the same time in good agreement with experiment. Performance of various semiempirical schemes in evaluating ESCA shifts is briefly discussed

Semiempirical versus ab Initio Calculations of Molecular Properties. I. Diamagnetic Susceptibilities and Quadrupole Moments in Some Medium Size Molecules

The self-consistent charge molecular orbital (SCC-MO) method was applied to a number of medium size molecules involving atoms exhibiting large differences in electronegativity and possessing one or more lone pairs. The quality of the wave functions thus obtained was applied to a number of medium size molecules involving atoms calculated by a rigorous treatment of the operators x2, y2, and z2• The SCC quadrupole moments can be favourably compared with the ab initio results of Snyder and Basch obtained by the use of a Gaussian double zeta basis set. The present results provide additional justification of the sec method, which has apparent advantages over the methods based on the ZDO approximation. Some difficulties encountered in the treatment of pi-electrons are discussed and suggestions for their remedy are given. The second moments calculated by the application of a simple additivity formula (Z. B. Maksic and J. E. Bloor, Chem. Phys. Lett., 13 (1972) 571; J. Phys. Chem., 77 (1973) 1520) and the related diamagnetic susceptibilities are in very good agreement with the ab initio values

Search for π0→νμνˉμ\pi^0 \to \nu_{\mu}\bar\nu_{\mu} Decay in LSND

We observe a net beam-excess of $8.7 \pm 6.3$ (stat) $\pm 2.4$ (syst) events, above 160 MeV, resulting from the charged-current reaction of $\nu_{\mu}$ and/or $\bar\nu_{\mu}$ on C and H in the LSND detector. No beam related muon background is expected in this energy regime. Within an analysis framework of $\pi^0 \to \nu_{\mu}\bar\nu_{\mu}$, we set a direct upper limit for this branching ratio of $\Gamma(\pi^0 \to \nu_\mu \bar\nu_\mu) / \Gamma(\pi^0 \to all) < 1.6 \times 10^{-6}$ at 90% confidence level.Comment: 4 pages, 4 figure

The Mre11-Rad50-Nbs1 complex mediates activation of TopBP1 by ATM

The activation of ATR-ATRIP in response to double-stranded DNA breaks (DSBs) depends upon ATM in human cells and Xenopus egg extracts. One important aspect of this dependency involves regulation of TopBP1 by ATM. In Xenopus egg extracts, ATM associates with TopBP1 and thereupon phosphorylates it on S1131. This phosphorylation enhances the capacity of TopBP1 to activate the ATR-ATRIP complex. We show that TopBP1 also interacts with the Mre11-Rad50-Nbs1 (MRN) complex in egg extracts in a checkpoint-regulated manner. This interaction involves the Nbs1 subunit of the complex. ATM can no longer interact with TopBP1 in Nbs1-depleted egg extracts, which suggests that the MRN complex helps to bridge ATM and TopBP1 together. The association between TopBP1 and Nbs1 involves the first pair of BRCT repeats in TopBP1. In addition, the two tandem BRCT repeats of Nbs1 are required for this binding. Functional studies with mutated forms of TopBP1 and Nbs1 suggested that the BRCT-dependent association of these proteins is critical for a normal checkpoint response to DSBs. These findings suggest that the MRN complex is a crucial mediator in the process whereby ATM promotes the TopBP1-dependent activation of ATR-ATRIP in response to DSBs

Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins

Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis

Economy, corruption or floating voters? Explaining the breakthroughs of Anti-Establishment Reform Parties in Eastern Europe

This paper discusses a new group of parties that we term anti-establishment reform parties (AERPs), which combine moderate social and economic policies with anti-establishment appeals and a desire to change the way politics is conducted. We analyse the electoral breakthroughs of AERPs in Eastern Europe (CEE), the region where AERPs have so been most successful. Examples include the Simeon II National Movement, GERB (Bulgaria), Res Publica (Estonia), New Era (Latvia), TOP09 and Public Affairs (Czech Republic) and Positive Slovenia. We examine the conditions under which such parties broke through in nine CEE states in 1997-2012 using Fuzzy Set Qualitative Comparative Analysis (fsQCA). We find five sufficient causal paths combining high or rising corruption, rising unemployment and party system instability. Rising corruption plays a key role in most pathways but, unexpectedly, AERP breakthroughs are more closely associated with economic good times than bad

Extraction and sensitive detection of toxins A and B from the human pathogen Clostridium difficile in 40 seconds using microwave-accelerated metal-enhanced fluorescence.

Clostridium difficile is the primary cause of antibiotic associated diarrhea in humans and is a significant cause of morbidity and mortality. Thus the rapid and accurate identification of this pathogen in clinical samples, such as feces, is a key step in reducing the devastating impact of this disease. The bacterium produces two toxins, A and B, which are thought to be responsible for the majority of the pathology associated with the disease, although the relative contribution of each is currently a subject of debate. For this reason we have developed a rapid detection assay based on microwave-accelerated metal-enhanced fluorescence which is capable of detecting the presence of 10 bacteria in unprocessed human feces within 40 seconds. These promising results suggest that this prototype biosensor has the potential to be developed into a rapid, point of care, real time diagnostic assay for C. difficile

Clostridioides difficile positivity rate and PCR ribotype distribution on retail potatoes in 12 European countries, January to June 2018

Background While human-to-human transmission of Clostridioides difficile occurs often, other infection sources, including food, animals and environment, are under investigation. Aim We present a large study on C. difficile in a food item in Europe, encompassing 12 European countries (Austria, France, Greece, Ireland, Italy, the Netherlands, Poland, Slovakia, Spain, Sweden, Romania and the United Kingdom). Methods Potato was selected because of availability, ease of sampling and high C. difficile positivity rates. Identical protocols for sampling and isolation were used, enabling a direct comparison of the C. difficile positivity rate. Results From C. difficile-positive potato samples (33/147; 22.4%), we obtained 504 isolates, grouped into 38 PCR ribotypes. Positivity rates per country varied (0–100%) and were at least 10% in 9/12 countries. No geographical clustering of samples with high positivity rates or in PCR ribotype distribution was observed. The most frequently detected PCR ribotypes (014/020, 078/126, 010 and 023) are also commonly reported in Europe among human clinically relevant isolates, in animal isolates and in the environment. Whole genome sequencing revealed several genetically related strain pairs (Spain/RT126, France/RT010, Austria and Sweden/RT276) and a cluster of very similar strains in RT078/126. Conclusion Our results suggest, the high potato contamination rates could have public health relevance. They indicate potatoes can serve as a vector for introducing C. difficile spores in the household environment, where the bacterium can then multiply in sensitive hosts with disrupted or unmature microbiota. Potato contamination with PCR ribotypes shared between humans, animals and soil is supportive of this view