Hydrophobic Mismatch Controls the Mode of Membrane-Mediated Interactions of Transmembrane Peptides

Various cellular processes require the concerted cooperative action of proteins. The possibility for such synchronization implies the occurrence of specific long-range interactions between the involved protein participants. Bilayer lipid membranes can mediate protein–protein interactions via relatively long-range elastic deformations induced by the incorporated proteins. We considered the interactions between transmembrane peptides mediated by elastic deformations using the framework of the theory of elasticity of lipid membranes. An effective peptide shape was assumed to be cylindrical, hourglass-like, or barrel-like. The interaction potentials were obtained for membranes of different thicknesses and elastic rigidities. Cylindrically shaped peptides manifest almost neutral average interactions—they attract each other at short distances and repel at large ones, independently of membrane thickness or rigidity. The hourglass-like peptides repel each other in thin bilayers and strongly attract each other in thicker bilayers. On the contrary, the barrel-like peptides repel each other in thick bilayers and attract each other in thinner membranes. These results potentially provide possible mechanisms of control for the mode of protein–protein interactions in membrane domains with different bilayer thicknesses.

Blockchain as Res Publica: Towards a Political Genealogy of a Distributed Ledger

This paper focuses on the political genealogy of one of the most promising and influential IT technologies of our time: the blockchain (or distributed registry). We point at important commonalities between the principles of blockchain projects and models of republican governance. In contrast to techno-anarchist and democratic ideas, the republican genealogy of blockchain has so far failed to attract the attention of researchers. After examining the basic technical properties and ideological images of blockchain, we explore how the four main principles of classical republicanism (personal freedom and autonomy of the individual; civic virtues; common good; recognition of great causes) are realized in influential blockchain projects — Bitcoin (developed by the pseudonymous Satoshi Nakamoto) and Ethereum (developed by Vitalik Buterin). The functioning of blockchain nodes is supported by a community of miners, who are free, but at the same time agree to act for the development of a common thing. What the republic and the blockchain have in common is that it is impossible to have a community without cooperative action. At the same time, blockchain is a vivid illustration of Bruno Latour's argument on the role of non-humans in social relations: his code seeks to replace untrustworthy humans with rule-acting nodes, and to create a cryptographic society where untrustworthy human relations are replaced by computers' relations. This article is an invitation to begin a discussion of the political ideas that are embedded in new technologies and the models of governance that are mobilized through them, often without proper reflection on the nature of such ideas by their creators.

Four Puzzles of Reputation-Based Cooperation

Research in various disciplines has highlighted that humans are uniquely able to solve the problem of cooperation through the informal mechanisms of reputation and gossip. Reputation coordinates the evaluative judgments of individuals about one another. Direct observation of actions and communication are the essential routes that are used to establish and update reputations. In large groups, where opportunities for direct observation are limited, gossip becomes an important channel to share individual perceptions and evaluations of others that can be used to condition cooperative action. Although reputation and gossip might consequently support large-scale human cooperation, four puzzles need to be resolved to understand the operation of reputation-based mechanisms. First, we need empirical evidence of the processes and content that form reputations and how this may vary cross-culturally. Second, we lack an understanding of how reputation is determined from the muddle of imperfect, biased inputs people receive. Third, coordination between individuals is only possible if reputation sharing and signaling is to a large extent reliable and valid. Communication, however, is not necessarily honest and reliable, so theoretical and empirical work is needed to understand how gossip and reputation can effectively promote cooperation despite the circulation of dishonest gossip. Fourth, reputation is not constructed in a social vacuum; hence we need a better understanding of the way in which the structure of interactions affects the efficiency of gossip for establishing reputations and fostering cooperation.

Deployment dynamics analysis of CALLISTO’s approach and landing system

Prior to landing of reusable space transportation systems, the vehicle’s landing legs needs to be fully deployed to enable a safe landing and further re-use of the space vehicle. During that phase the deployment system has to overcome harsh and challenging environmental conditions. In this study, a numerical simulator is developed in order to investigate these influences on the landing leg deployment dynamics. By means of an extensive aerodynamic database and a broad approach flight domain, the influence of aerodynamics, exhaust plume, and vehicle’s attitude on the deployment dynamics is analyzed. This study shows on the example of the first stage demonstrator CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss back Operations), that thrust level, vehicle attitude, and the deployment system parameters affect the deployment performance.

Synthesis and Characterization of Antibacterial Viscose Nonwoven Fabric by the Cooperative Action of Se Nanoparticles and Amino Hyperbranched Polymer

This research provides a new method for preparing nanoparticle-coated cellulose fabrics, which has broad application prospects in the functional fiber industry. In this work amino-terminated hyperbranched poly (HBP)-capped Selenium nanoparticles (Se NPs) were synthesized for coating viscose nonwoven fabric (VNF) via impregnation method to produce a controllable and uniform Se NPs coating on the viscose fiber surface. The prepared Se NPs and the treated VNF were characterized by the transmission electron microscope (TEM), x-ray diraction (XRD), x-ray photoelectron spectroscopy (XPS), field emission scanning electron microcopy (FE-SEM), and antibacterial measurement. The results indicate that the Se NPs were spherical shaped with an average size of 10 nm. FESEM, XRD, and XPS characterizations demonstrated that Se NPs can adsorbed and distributed uniformly on the fiber surface. Se NPs-coated VNF showed above 99.9% bacterial reduction of Staphylococcus aureus and Escherichia coli while the Se element content on VNF was about 292 mg/kg.

Strategic Interactions and Uncertainty in Decisions to Curb Greenhouse Gas Emissions

This paper examines the strategic interactions of two large regions making choices about greenhouse gas emissions in the face of rising global temperatures. Three central features are highlighted: uncertainty, the incentive for free riding, and asymmetric characteristics of decision makers. Optimal decisions are modelled in a fully dynamic, feedback Stackelberg pollution game. Global average temperature is modelled as a mean reverting stochastic process. A numerical solution of a coupled system of Hamilton-Jacobi-Bellman equations is implemented and the probability distribution of outcomes is illustrated with Monte Carlo simulation. When players are identical, the outcome of the game is much worse than the social planner’s outcome. An increase in temperature volatility reduces player utility, making cooperative action through a social planner more urgent. Asymmetric damages or asymmetric preferences for emissions reductions are shown to have important effffects on the strategic interactions of players.

Cooperative Control of Microgrids: A Review of Theoretical Frameworks, Applications and Recent Developments

The development of cooperative control strategies for microgrids has become an area of increasing research interest in recent years, often a result of advances in other areas of control theory such as multi-agent systems and enabled by rapid advances in wireless communications technology and power electronics. Though the basic concept of cooperative action in microgrids is intuitively well-understood, a comprehensive survey of this approach with respect to its limitations and wide range of potential applications has not yet been provided. The objective of this paper is to provide a broad overview of cooperative control theory as applied to microgrids, introduce other possible applications not previously described, and discuss recent advances and open problems in this area of microgrid research.

Action inquiry and vocal ergonomics: A pilot study with sports coaches

BACKGROUND: Coaches critically rely on voice for occupational functioning, which has associated risks to vocal health. However, vocal occupational health and safety (OHS) and vocal ergonomics are not typically considered for, by, or with coaches. OBJECTIVE: This study piloted a participatory approach to vocal ergonomics, aiming to collaboratively (i) understand coaches’ vocally reliant occupational participation, and (ii) consider vocal ergonomic factors. METHODS: This research was undertaken at an international tournament for floorball (also known as ‘Innebandy’, ‘Salibandy’, or ‘Unihockey’). Three national coaches (n = 3) and the lead researcher undertook cooperative action inquiry. This piloted a participatory vocal ergonomics programme. Action inquiry methods included fieldnotes, interviews, observations, a workshop, ergonomics approaches, and a focus group. Multi-level analyses supported the findings, including categorical aggregation, direct interpretation, and reflexive thematic analysis. RESULTS: Participants identified vocal ergonomic factors present at the tournament; including personal, activity, physical environmental, and organisational factors. Participants developed four vocal ergonomic approaches responsive to factors. These were: (1) player consultation, (2) ongoing feedback discussions, (3) movement and postural change, and (4) specific task adaptation. Approaches 1–2 directly supported coaches’ voices. Coaches posited limitations to other strategies, but made recommendations for future use. Coaches also reflected that this collaboration provided actionable voice insights and opportunities to address vocal ergonomics. They advocated for extended engagement with coaches, increased focus on vocal health, and inclusion of early career coaches in future programmes. CONCLUSIONS: These findings support engagement of coaches, and other vocally reliant workers, in addressing voice use and vocal health at work.

Arabidopsis ASYMMETRIC LEAVES2 (AS2): roles in plant morphogenesis, cell division, and pathogenesis

The ASYMMETRIC LEAVES2 (AS2) gene in Arabidopsis thaliana is responsible for the development of flat, symmetric, and extended leaf laminae and their vein systems. AS2 protein is a member of the plant-specific AS2/LOB protein family, which includes 42 members comprising the conserved amino-terminal domain referred to as the AS2/LOB domain, and the variable carboxyl-terminal region. Among the members, AS2 has been most intensively investigated on both genetic and molecular levels. AS2 forms a complex with the myb protein AS1, and is involved in epigenetic repression of the abaxial genes ETTIN/AUXIN RESPONSE FACTOR3 (ETT/ARF3), ARF4, and class 1 KNOX homeobox genes. The repressed expression of these genes by AS2 is markedly enhanced by the cooperative action of various modifier genes, some of which encode nucleolar proteins. Further downstream, progression of the cell division cycle in the developing organs is stimulated; meristematic states are suppressed in determinate leaf primordia; and the extension of leaf primordia is induced. AS2 binds the specific sequence in exon 1 of ETT/ARF3 and maintains methylated CpGs in several exons of ETT/ARF3. AS2 forms bodies (designated as AS2 bodies) at nucleolar peripheries. AS2 bodies partially overlap chromocenters, including inactive 45S ribosomal DNA repeats, suggesting the presence of molecular and functional links among AS2, the 45S rDNAs, and the nucleolus to exert the repressive regulation of ETT/ARF3. The AS2/LOB domain is characterized by three subdomains, the zinc finger (ZF) motif, the internally conserved-glycine containing (ICG) region, and the leucine-zipper-like (LZL) region. Each of these subdomains is essential for the formation of AS2 bodies. ICG to LZL are required for nuclear localization, but ZF is not. LZL intrinsically has the potential to be exported to the cytoplasm. In addition to its nuclear function, it has been reported that AS2 plays a positive role in geminivirus infection: its protein BV1 stimulates the expression of AS2 and recruits AS2 to the cytoplasm, which enhances virus infectivity by suppression of cytoplasmic post transcriptional gene silencing.

Establishing and maintaining property transactions data banks in Ghana through partnerships and participatory means

PurposeThe credibility of valuation is enhanced by the use of quality and reliable property market data. Nonetheless, the availability of quality and reliable market data remains a problem for valuers in Ghana, as current market data sources are tainted with issues of reliability. The purpose of this study is to examine the possibility of establishing property market data banks in Ghana, to help solve the market data problem faced by valuers.Design/methodology/approachThis study adopted a mixed-method approach consisting of the identification and review of literature, interviews with officials from the Lands Valuation Division of the Lands Commission and a questionnaire survey of property valuers.FindingsThe study finds that it is possible for property market data banks to be established, and in the absence of facilitating legislation, partnerships among various stakeholders are the best way of achieving this. The study identifies the lack of initiative and the lack of partnerships among the various stakeholders inter alia as the major factors limiting the establishment of property market data banks. The findings imply a need for stakeholders to take initiative to establish a property market data bank aimed at improving the quality and reliability of market data to enhance the valuation practice.Originality/valueThe study asserts the possibility of creating a property market data bank in Ghana, notwithstanding the limiting factors. The findings will provide a basis for relevant institutions and agencies to take cooperative action for the establishment of property market data banks, towards enhancing the valuation practice in Ghana as well as in other developing countries. The study will also prompt research into various tools and mechanisms to be adopted towards the establishment of property market data banks through participatory means.