DNA interaction of the CcrM DNA methyltransferase: a mutational and modeling study

Caulobacter crescentus CcrM is a DNA-(adenine N6)-methyltransferase that methylates adenine in the sequence GANTC with high specificity. To investigate its mechanism of DNA recognition, we used the crystal structure of a related methyltransferase (M1.MboII, which modifies GAAGA) as a starting point, and docked into it a DNA substrate to identify the protein regions that approach the DNA. After alignment of CcrM and M1.MboII, we identified four candidate regions in CcrM to contain residues involved in DNA recognition. We mutated 20 amino acid residues within these regions, purified the CcrM variants, and determined their DNA-binding and catalytic activity on a cognate GANTC substrate and on nine near-cognate substrates, each of which contained a single base-pair substitution in the recognition sequence. Altogether, we identified four residues in two of the regions, mutations of which resulted in a strong (>100-fold) reduction of methylation activity. Our data show that DNA recognition by CcrM is a cooperative process, because disruption of critical contacts led to loss of catalytic activity but not to a relaxation in specificity. In addition, we identified a change in the readout of the fifth base pair in the GANTC sequence with two other CcrM variants that showed smaller reductions in overall activity. Based on this and the sequence alignment of CcrM with other DNA methyltransferases of same or related recognition sequence, we propose roles for these two regions in DNA recognition by CcrM.     

The estimation of corrosion behaviour of ZrTi binary alloys for dental applications using electrochemical techniques

Titanium and zirconium are in the same group in the periodic table of elements and are known to have similar physical and chemical properties. Both Ti and Zr usually have their surfaces covered by a thin oxide film spontaneously formed in air. However, the cytotoxicity of ZrO₂ is lower than that of TiO₂ rutile. Treatments with fluoride are known as the main methods to prevent plaque formation and dental caries. The corrosion behaviour of ZrTi alloys with Ti contents of 5, 25 and 45 wt.% and cp-Ti was investigated for dental applications. All samples were tested by linear potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) performed in artificial saliva with different pH levels (5.6 and 3.4) and different fluoride (1000 ppm F⁻) and albumin protein (0.6%) contents. In addition, scanning electron microscopy (SEM) was employed to observe the surface morphology of the test materials after linear potentiodynamic polarisation. The corrosion current densities for the ZrTi alloys increased with the titanium content. The Zr5Ti and Zr25Ti alloys were susceptible to localised corrosion. The role that Ti plays as an alloying element is that of increasing the resistance of ZrTi alloy to localised corrosion. The presence of 0.6% albumin protein in fluoridated acidified artificial saliva with 1000 ppm F⁻ could protect the cp-Ti and ZrTi alloys from attack by fluoride ions.     

Multidimensional urban segregation: toward a neural network measure

We introduce a multidimensional, neural network approach to reveal and measure urban segregation phenomena, based on the self-organizing map algorithm (SOM). The multidimensionality of SOM allows one to apprehend a large number of variables simultaneously, defined on census blocks or other types of statistical blocks, and to perform clustering along them. Levels of segregation are then measured through correlations between distances on the neural network and distances on the actual geographical map. Further, the stochasticity of SOM enables one to quantify levels of heterogeneity across census blocks. We illustrate this new method on data available for the city of Paris.

     

Conceptual approaches to wellbeing in buildings: a scoping review

ABSTRACT

Several industry-led initiatives in various countries demonstrate a new interest in wellbeing and buildings. This paper adopts a scoping review method aiming to establish the most prevalent and insightful definitions and dimensions of wellbeing in buildings applied in the recent published literature. The paper adopts a two-step method for identifying and categorizing the conceptual approaches to wellbeing encountered in the current literature. First, an overview is presented of the term ‘wellbeing’ and its development over time. Second, the broad wellbeing categories identified are further refined and complemented via a deductive approach, drawing the final set of conceptual themes informed by the papers reviewed in this study. Nine themes were identified, two of which deductively emerged from the papers included in this study: environmental satisfaction/comfort and cognitive performance/productivity. The findings emphasize the heterogeneity of conceptual approaches to research concerning ‘wellbeing in buildings’, an ambiguity between wellbeing outcomes or determinants, and the need for greater clarity on the relative contributions of different wellbeing dimensions to overall individual or population wellbeing. Based on these findings, future work could be carried out to provide guidance on how to evaluate claims of evidence-based building design which foster individual or population wellbeing.     

Sarcoidosis presenting as obstructive jaundice

Sarcoidosis is an uncommon disorder characterized by a multi-systemic granulomatous disease of undetermined etiology and pathogenesis. The diagnosis is established by the presence of a compatible clinical illness and by histologic demonstration of noncaseating epithelioid cell granulomas in the affected organs. Accurate diagnosis requires a thorough evaluation to exclude infectious and neoplastic diseases that can mimic sarcoidosis. Although all organs and systems can be affected, the lungs and intrathoracic lymph glands are the most common sites of involvement. We describe an unusual case of extrapulmonary sarcoidosis presenting as obstructive jaundice.     

Client and counselor characteristics and engagement in counseling.

Examined relations among various client and counselor characteristics and engagement in counseling for more than 1 session with 5 female and 4 male practicum counselors and 203 of their clients (128 women, 75 men) who had come to a university counseling center for the 1st time. After the initial interview, clients rated counselors' interest, helpfulness, competence, warmth, and genuineness; counselors rated clients' verbalness, intelligence, capacity for insight, likability, and the severity of clients' problems. Clients also indicated the extent to which counselors identified concerns for which the clients did not initially seek counseling. Findings show that 71 clients returned for more than 1 counseling session. Counselors' perceptions of clients as more disturbed and counselors' desire to see the clients were positively associated with clients' returning for counseling after intake. Identification of concerns for clients by counselors at intake was also positively related to engagement in counseling. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural impact of nitrogen incorporation on properties of alkali germanophosphate glasses

The structure, atomic packing density, calorimetric glass transition, and hardness of mixed sodium–lithium germanophosphate oxynitride glasses with varying Ge/P and N/P ratios were investigated. The combined influences of nitridation and mixed network former effect (MNFE) on the glass structure were analyzed using Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and ³¹P nuclear magnetic resonance (NMR) spectroscopy. Evidence for the existence of germanium in a higher coordination state, i.e., five‐ or sixfold coordination, was obtained by performing XPS analysis of the oxide glasses, with indication of conversion to tetrahedral coordination upon nitridation. Raman spectroscopy measurements implied that the germanate network was modified upon nitridation, including the removal of ring‐like germanate structures and P–O–Ge mixed linkages. The partial anionic N‐for‐O substitution gave rise to the linear dependence of the glass transition temperature (T_g) and hardness (H_V) on nitrogen content (expressed as N/P ratio), especially for lower Ge/P ratio. However, nitridation also caused an unexpected increase in liquid fragility and decrease in density. This suggests that the governing structural parameter for property evolution in such LiNaGePON glasses is not only the increased degree of cross‐linking of the phosphate chains, but rather the short‐ and intermediate‐range structural modifications within the germanate component of the oxynitride glasses.     

Team experiential cognitive style and team performance: The moderating impact of workplace setting

With an increasing need in organizations to come up with novel and useful ideas to renew and survive, team creativity has grown in importance to managers and researchers. As the cognitive resources of team members are the core input for team creativity, researchers increasingly look at team cognition in general and team cognitive styles in particular. In this research stream, the environmental context in which team members are embedded has received limited attention. We therefore experimentally test variation in the physical workplace environment and how it influences the relationship between team experiential cognitive styles and team creativity. Manipulating the nature of architectural elements in the room, we distinguish between a physical workplace with (i) experiential cues and (ii) rational cues. We also use a control condition where architectural elements are absent in the workplace environment. We rely on resource‐matching theory to build our hypotheses. Using data of 75 student teams of a Dutch university, we find that the relationship between teams' experiential cognitive style and team creativity was positive in the control condition. This positive relationship became insignificant in the two conditions where experiential or rational cues were introduced. Theoretical and practical implications are discussed.     

Parallelization and improvement of the MDV-SW algorithm for HEVC intra-prediction coding

The Journal of Supercomputing - The new video coding standard high-efficiency video encoding (HEVC) greatly improves the efficiency of intra-prediction with respect to previous standards. However,...     

Formalizing Cognitive Acceptance of Arguments: Durum Wheat Selection Interdisciplinary Study

In this paper we present an interdisciplinary approach that concerns the problem of argument acceptance in an agronomy setting. We propose a computational cognitive model for argument acceptance based on the dual model system in cognitive psychology. We apply it in an agronomy setting within a French national project on durum wheat.