Folding thermodynamics of model four-strand antiparallel beta-sheet proteins

The thermodynamic properties for three different types of off-lattice four-strand beta-sheet protein models interacting via a hybrid Go-type potential have been investigated. Discontinuous molecular dynamic simulations have been performed for different sizes of the bias gap g, an artificial measure of a model protein's preference for its native state. The thermodynamic transition temperatures are obtained by calculating the squared radius of gyration, the root-mean-squared pair separation fluctuation, the specific heat, the internal energy of the system, and the Lindemann disorder parameter. In spite of the simplicity, the protein-like heteropolymers have shown a complex set of protein transitions as observed in experimental studies. Starting from high temperature, these transitions include a collapse transition, a disordered-to-ordered globule transition, a folding transition, and a liquid-to-solid transition. These transitions strongly depend on the native-state geometry of the model proteins and the size of the bias gap. A strong transition from the disordered globule state to the ordered globule state with large energy change and a weak transition from the ordered globule state to the native state with small energy change were observed for the large gap models. For the small gap models no native structures were observed at any temperature, all three beta-sheet proteins fold into a partially-ordered globule state which is geometrically different from the native state. For small bias gaps at even lower temperatures, all protein motions are frozen indicating an inactive solid-like phase.Comment: PDF file, 32 pages including 13 figure page

Anger and repression : a test of a model

Anger or more specifically, repression, suppression or difficulties in coping with anger has achieved prominence in the literature of psychological medicine, as contributing or etiological factors in hypertension, coronary heart disease and cancer. In past studies, 'repression', operationally defined by a pattern of high defensiveness and low trait anxiety, has been linked consistently with elevated physiological arousal during stressful laboratory tasks, despite low self-reported disturbance. This model for operationalizing repression has also been used in studies which demonstrate that repression is associated with restricted access to memories from childhood and that this is particularly so for negative emotional experiences. The current research was designed to extend the previously mentioned model of repression to anger, to test whether similar effects to those noted in research into repression of anxiety also exist in anger repression. Defensiveness and trait anger were used to operationalize repression of anger and five groups of subjects participated in free-recall of angry, anxious and happy experiences from childhood. Heart rate, skin conductance level and facial skin temperature were monitored throughout baseline and recall, and subjective involvement during recall was assessed. Mixed-sex samples comprised eight 'repressors of anger', 10 'true-low angry' and 10 'true-high angry' subjects, eight traditionally-defined 'repressors of anxiety', and six individuals who repressed both emotions; the latter two groups being included to permit comparison of repressors of anger with repressors of anxiety and to allow for evaluation of possible additivity of effects in repression. Results revealed no group differences in physiological, subjective arousal, or access to affective memories. Explanations for the absence of effects similar to those in repression of anxiety were sought, both in terms of methodology and conceptual issues examining differences between the emotions of anger and anxiety. The latter suggested that repression of these emotions may not operate in a similar manner

Experiences of Jordanian Mothers and Fathers of Children with Cancer

Previous studies investigating psychological stress of parents of a child with cancer have shown inconsistent findings about parental perceived stress whose children have cancer and most of these studies were established in Western communities (with none in the Arab world). Additionally, the majority of published research focused on mothers. Therefore, the aim of this study is to explore perceived stress in mothers and fathers (couples) parenting a child with cancer in Jordan. Such an exploration may contribute to the existing literature and improve overall family survivorship experiences following childhood cancer in Jordan. This qualitative study used semistructured interviews of 12 mothers and 12 fathers parenting a child with cancer in Jordan. Parents of children of various cancer diagnoses were interviewed and the ages of children were between six months and 14 years. Most mothers admitted that being with the ill child most of the time and therefore away from other healthy children, relatives and friends was the main cause of stress. However, most fathers said that employment status and financial burden were their main causes of stress after their child’s health status. Most of the interviewed couples commented that they were sharing the life situation with their partners, helping and supporting each other to overcome the challenges. Results of this study highlight the importance of recognizing the psychological needs of Jordanian mothers and fathers of a child with cancer not only at the time of diagnosis but also during the cancer journey

Can Pay Regulation Kill? Panel Data Evidence on the Effect of Labor Markets on Hospital Performance

Labor market regulation can have harmful unintended consequences. In many markets, especially for public sector workers, pay is regulated to be the same for individuals across heterogeneous geographical labor markets. We would predict that this will mean labor supply problems and potential falls in the quality of service provision in areas with stronger labor markets. In this paper we exploit panel data from the population of English acute hospitals where pay for medical staff is almost flat across the country. We predict that areas with higher outside wages should suffer from problems of recruiting, retaining and motivating high quality workers and this should harm hospital performance. We construct hospital-level panel data on both quality - as measured by death rates (within hospital deaths within thirty days of emergency admission for acute myocardial infarction, AMI) - and productivity. We present evidence that stronger local labor markets significantly worsen hospital outcomes in terms of quality and productivity. A 10% increase in the outside wage is associated with a 4% to 8% increase in AMI death rates. We find that an important part of this effect operates through hospitals in high outside wage areas having to rely more on temporary "agency staff" as they are unable to increase (regulated) wages in order to attract permanent employees. By contrast, we find no systematic role for an effect of outside wages of performance when we run placebo experiments in 42 other service sectors (including nursing homes) where pay is unregulated.labor market regulation, hospital quality, hospital productivity, skills

The middle-class African American home: its objects and their meanings

The purpose of this study was to explore the sense of self middle-class African American families convey in their homes, how they express themselves and construct their identities through objects in their homes, including textile-related objects, and the meanings these objects hold for them. This phenomenon was explored through a constructivist, interpretive paradigm approach.;Data was collected from nine married couples in the form of long interviews that were audiotaped, videotapes and photographs of their homes and objects within them. The data were interpreted using case study and grounded theory approaches that allowed the researcher to understand the meanings of home and its objects in the lives of middle-class African American married couples and also to delve into new issues as the participants introduced them.;Grounded theory analysis revealed two overarching emergent themes within the data: (1) African American ethnicity issues, and (2) African American religion. These two overarching emergent themes were embedded in twelve minor themes within the data: (1) open home life, (2) personal spaces within the home, (3) home and objects reflecting family relations, (4) decorating the home, (5) disposal, (6) practicality versus status, (7) accomplishments, (8) utilitarian, (9) uniqueness, (10) memories, (11) hedonics, (12) textiles and clothing, and (13) miscellaneous. The findings of this study revealed that middle-class African American families convey a sense of self in their homes through home itself and its objects that (1) reinforce their ethnic pride and identity, celebrate their heritage, deal with real estate discrimination issues, and (2) reflect their religious values, faith, spiritual beliefs, and God-centered beliefs. The data indicated that the Midwestern sample of participants in this study very rarely used textile-related objects to convey a sense of self in their homes. The findings supported the theoretical framework of house and home, symbolic interaction theory, meanings and symbols, and setting/definition of the situation

Dynamical self-assembly of dipolar active Brownian particles in two dimensions

Based on Brownian Dynamics (BD) simulations, we study the dynamical self-assembly of active Brownian particles with dipole–dipole interactions, stemming from a permanent point dipole at the particle center. The propulsion direction of each particle is chosen to be parallel to its dipole moment. We explore a wide range of motilities and dipolar coupling strengths and characterize the corresponding behavior based on several order parameters. At low densities and low motilities, the most important structural phenomenon is the aggregation of the dipolar particles into chains. Upon increasing the particle motility, these chain-like structures break, and the system transforms into a weakly correlated isotropic fluid. At high densities, we observe that the motility-induced phase separation is strongly suppressed by the dipolar coupling. Once the dipolar coupling dominates the thermal energy, the phase separation disappears, and the system rather displays a flocking state, where particles form giant clusters and move collective along one direction. We provide arguments for the emergence of the flocking behavior, which is absent in the passive dipolar system.TU Berlin, Open-Access-Mittel - 2020DFG, 65143814, GRK 1524: Self-Assembled Soft-Matter Nanostructures at Interface

Response To Intervention: Research And Practice

Responseto Intervention (RTI) is a service model designed to meet the learning needs ofstudents prior to diagnosis and placement in special education settings.  Results of a quantitative quasi-experimentalresearch study to investigate the relationship between the RTI plan andself-reported implementation practices among general education elementaryteachers in a Florida school district using analysis of variance (ANOVA) revealedno significant difference between demonstration school and comparable schoolgeneral education teachers’ self-reported practices,  self-reported implementation success rates, orself-reported data collection responsibilities. Recommendations for professional development opportunities for allteachers, paraprofessionals, and administrators involved in the RTI process basedupon analyzed research study data are included

Generic model for tunable colloidal aggregation in multidirectional fields

Based on Brownian Dynamics computer simulations in two dimensions we investigate aggregation scenarios of colloidal particles with directional interactions induced by multiple external fields. To this end we propose a model which allows continuous change in the particle interactions from point-dipole-like to patchy-like (with four patches). We show that, as a result of this change, the non-equilibrium aggregation occurring at low densities and temperatures transforms from conventional diffusion-limited cluster aggregation (DLCA) to slippery DLCA involving rotating bonds; this is accompanied by a pronounced change of the underlying lattice structure of the aggregates from square-like to hexagonal ordering. Increasing the temperature we find a transformation to a fluid phase, consistent with results of a simple mean-field density functional theory

Structural Properties of Mixtures of Highly Asymmetrical Electrolytes and Uncharged Particles using the Hypernetted Chain Approximation

We have solved the Ornstein-Zernike equation in the hypernetted chain (HNC) approximation for several mixtures of electrolytes and uncharged hard spheres. The mixtures that we studied range from a simple restricted primitive model plus hard spheres of the same size to highly asymmetric electrolytes plus hard spheres of different sizes. We monitored the radial distribution function and thermodynamic properties. We find that the presence of neutral particles changes the nature of the interaction between the charged particles. We also find a strong correlation between nonelectrostatic and electrostatic contributions to the free energy of the mixtures. Potential applications of this approach to the study of protein solubility in solutions of nonionic polymers are discussed. © 1994 American Institute of Physics