Characterisation of ICAM-3 and extracellular vesicles in the clearance of apoptotic cells

Apoptotic cell clearance by phagocytes is a vital part of programmed cell death that prevents dying cells from undergoing necrosis which may lead to inflammatory and autoimmune disorders. Apoptotic cells (AC) are removed by phagocytes, in a process that involves 'find me' and 'eat me' signals that facilitate the synapsing and engulfment of cell corpses. Extracellular vesicles (EV) are shed during apoptosis and promote phagocyte recruitment. Binding of AC is achieved by multiple ligand-receptor interactions. One interesting AC associated ligand is ICAM-3, a highly glycosylated adhesion molecule of the IgSF family, expressed on human leukocytes. On viable cells ICAM-3 participates in initiating immune responses, whereas on AC we show it attracts phagocytes through EV and aids in the binding of AC to the phagocytes. This project aims to characterize the role of ICAM-3 and EV in the clearance of AC and to identify the mechanisms that underlie their function in apoptotic cell clearance. Human B cells induced to apoptosis by UV irradiation were observed during their progression from viable to apoptotic via flow cytometry. The involvement of ICAM-3 in mediating interaction between AC and MØ was assessed. The ability of ICAM3 on EV to mediate chemoattraction was observed using chemotaxis assays. Additionally the anti-inflammatory effect was assessed using LPS-induced TNF-α production that suggested it may have anti-inflammatory effects. Future work in this project will assess the role of ICAM3 on EV from different phases of apoptosis to exert functional effects both in vitro and in vivo.

The involvement/exclusion paradox of spontaneous volunteering:new lessons from winter flood episodes in England

This article focuses on the involvement and management of spontaneous volunteers (SVs). It develops a new theory—which we call the “involvement/exclusion” paradox—about a situation which is frequently manifested when SVs converge in times of disaster. After reviewing research and policy guidance relating to spontaneous volunteering, we present findings from a study of responses to winter flood episodes in England. Taking together the empirical findings and the literature, the article analyzes elements inherent in the involvement/exclusion paradox and develops a conceptual model to illustrate and explain the paradox. Implications for managers and future research are discussed.

Átmenet vagy spontán rend(etlenség)? = Transition or spontaneous order/disorder?

Az írás arra a kérdésre keresi a választ, hogy a két évtized után tartóssá, vagyis trenddé váló gazdasági és társadalmi eltérések a "posztkommunista" országok között milyen okokra vezethetők vissza. Másodsorban azt elemzi, mi a jelentősége e sokrétű különbségek modellszerű kategorizálásának. Ennek alapja az állami szerepvállalás mértéke és minősége. Végül harmadikként azt a kérdéskört vizsgálja, hogy az eltérések milyen következményekkel járnak. A fő következtetés az, hogy a közösségi választások ugyan jelentősek, ezek szerepe azonban a pályafüggőséghez képest sokkal kisebb, mint azt a legtöbb elmélet föltételezi. Az eredmény - Hayekkel szólva (Hayek [1995]) - emberi cselekvés, ámde nem emberi tervezet szülötte. _____ The article seeks to discover what causes can be traced for the economic and social differences that have become permanent or a trend after two decades. Secondly, it analy-ses what importance this model-like categorization of manifold differences bears. Thirdly and lastly, it examines the sphere of questions to do with the consequences of these differences. The main conclusion is that the community choices are significant, but their role is much less, by comparison with career dependence, than most theories assume. Achievement, to quote Hayek (1995) is borne of human endeavour, not human planning.

Spontaneous order and social norms. Hayek’s theory of socio-cultural evolution

Hayek’s theory of socio-cultural evolution is a generalization of his theory on spontaneous market order. Hayek explains both the emergence of market and social institutions serving as a social basis for that order within the framework of a unified evolutionary logic. This logic interprets the emergence and survival of spontaneous order and group-level rules of conduct as an unintended consequence of human action. In order to explain the emergence of social norms exclusively on the basis of methodological individualism, one would have to give up an exclusively evolutionary explanation of these norms. Since Hayek applies the invisible-hand explanation to the investigation of social norms, he combines the position of methodological individualism with functionalist-evolutionary arguments in his analysis. Hayek’s theory of socio-cultural evolution represents a theory in the framework of which methodological individualism and functionalism do not crowd out but complement each other.

Spontaneous order and social norms. Hayek’s theory of socio-cultural evolution

Hayek's theory of socio-cultural evolution is a generalization of his theory on spontaneous market order. Hayek explains both the emergence of market and social institutions serving as a social basis for that order within the framework of a unified evolutionary logic. This logic interprets the emergence and survival of spontaneous order and group-level rules of conduct as an unintended consequence of human action. In order to explain the emergence of social norms exclusively on the basis of methodological individualism, one would have to give up an exclusively evolutionary explanation of these norms. Since Hayek applies the invisiblehand explanation to the investigation of social norms, he combines the position of methodological individualism with functionalist-evolutionary arguments in his analysis. Hayek's theory of socio-cultural evolution represents a theory in the framework of which methodological individualism and functionalism do not crowd out but complement each other.

Physiological response measures (respiration, clearance, byssus production, survival) of Perna viridis during a 91 day exposure experiment to microplastics in Bogor, Indonesia, 2014

Perna viridis from the Bay of Jakarta was exposed to different concentrations (0, 21.6, 216 and 2160 mg/l) of PVC microplastic particles for 91 days in a controlled laboratory experiment. Particles were negatively buoyant, but were regularly resuspended from the sediment, mimicking tidal events. The particles were contaminated with the organic pollutant fluoranthene, except for one control group, which was exposed to the highest plastic concentration (2160 mg/l) but with clean particles. Within the 91 days survival was monitored. After 40 - 44 days of the exposure, physiological responses of all mussel individuals were measured. Respiration rates were measured as the decrease of oxygen in a sealed container in 20 minutes. Clearance rates were determined by measuring the depletion of algal cells in the water in 30 minutes. Byssus production was assessed by counting the number of newly formed byssus discs within 24 hours.

Compilation of maximum ingestion and maximum clearance rate data for marine pelagic organisms

The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size within taxa is related to the inherent decrease in feeding efficiency of any particular feeding mode. The transitions between feeding mode and simultaneous transitions in clearance and respiration rates may then represent adaptations to the food environment and be the result of the optimization of tradeoffs that allow sufficient feeding and growth rates to balance mortality.

A framework for investigating the use of face features to identify spontaneous emotions

Emotion-based analysis has raised a lot of interest, particularly in areas such as forensics, medicine, music, psychology, and human-machine interface. Following this trend, the use of facial analysis (either automatic or human-based) is the most common subject to be investigated once this type of data can easily be collected and is well accepted in the literature as a metric for inference of emotional states. Despite this popularity, due to several constraints found in real world scenarios (e.g. lightning, complex backgrounds, facial hair and so on), automatically obtaining affective information from face accurately is a very challenging accomplishment. This work presents a framework which aims to analyse emotional experiences through naturally generated facial expressions. Our main contribution is a new 4-dimensional model to describe emotional experiences in terms of appraisal, facial expressions, mood, and subjective experiences. In addition, we present an experiment using a new protocol proposed to obtain spontaneous emotional reactions. The results have suggested that the initial emotional state described by the participants of the experiment was different from that described after the exposure to the eliciting stimulus, thus showing that the used stimuli were capable of inducing the expected emotional states in most individuals. Moreover, our results pointed out that spontaneous facial reactions to emotions are very different from those in prototypic expressions due to the lack of expressiveness in the latter.

Deliberate and spontaneous sensations of disembodiment:capacity or flaw?

Introduction: Hallucinations that involve shifts in the subjectively experienced location of the self, have been termed “out-of-body experiences” (OBEs). Early psychiatric accounts cast OBEs as a specific instance of depersonalisation and derealisation disorder (DPD-DR). However, during feelings of alienation and lack of body realism in DPD-DR the self is experienced within the physical body. Deliberate forms of “disembodiment” enable humans to imagine another’s visuo-spatial perspective taking (VPT), thus, if a strong relationship between deliberate and spontaneous forms of disembodiment could be revealed, then uncontrolled OBEs could be “the other side of the coin” of a uniquely human capacity. Methods: We present a narrative review of behavioural and neuroimaging work emphasising methodological and theoretical aspects of OBE and VPT research and a potential relationship. Results: Results regarding a direct behavioural relationship between VPT and OBE are mixed and we discuss reasons by pointing out the importance of using realistic tasks and recruiting genuine OBEers instead of general DPD-DR patients. Furthermore, we review neuroimaging evidence showing overlapping neural substrates between VPT and OBE, providing a strong argument for a relationship between the two processes. Conclusions: We conclude that OBE should be regarded as a necessary implication of VPT ability in humans, or even as a necessary and potentially sufficient condition for the evolution of VPT.

Spontaneous Unfolding and Refolding of FNIII Domains Assayed by Thiol Exchange

Fibronectin (FN) is a large extracellular matrix (ECM) protein that is made up of

type I (FNI), type II (FNII), & type III (FNIII) domains. It assembles into an insoluble

supra-­‐‑molecular structure: the fibrillar FN matrix. FN fibrillogenesis is a cell‐‑mediated process, which is initiated when FN binds to integrins on the cell surface. The FN matrix plays an important role in cell migration, proliferation, signaling & adhesion. Despite decades of research, the FN matrix is one of the least understood supra-­‐‑molecular protein assemblies. There have been several attempts to elucidate the exact mechanism of matrix assembly resulting in significant progress in the field but it is still unclear as to what are FN-­‐‑FN interactions, the nature of these interactions and the domains of FN that

are in contact with each other. FN matrix fibrils are elastic in nature. Two models have been proposed to explain the elasticity of the fibrils. The first model: the ‘domain unfolding’ model postulates that the unraveling of FNIII domains under tension explains fibril elasticity.

The second model relies on the conformational change of FN from compact to extended to explain fibril elasticity. FN contain 15 FNIII domains, each a 7-­‐‑strand beta sandwich. Earlier work from our lab used the technique of labeling a buried Cys to study the ‘domain unfolding’ model. They used mutant FNs containing a buried Cys in a single FNIII domain and found that 6 of the 15 FNIII domains label in matrix fibrils. Domain unfolding due to tension, matrix associated conformational changes or spontaneous folding and unfolding are all possible explanation for labeling of the buried Cys. The present study also uses the technique of labeling a buried Cys to address whether it is spontaneous folding and unfolding that labels FNIII domains in cell culture. We used thiol reactive DTNB to measure the kinetics of labeling of buried Cys in eleven FN III domains over a wide range of urea concentrations (0-­‐‑9M). The kinetics data were globally fit using Mathematica. The results are equivalent to those of H-­‐‑D exchange, and

provide a comprehensive analysis of stability and unfolding/folding kinetics of each

domain. For two of the six domains spontaneous folding and unfolding is possibly the reason for labeling in cell culture. For the rest of the four domains it is probably matrix associated conformational changes or tension induced unfolding.

A long-­‐‑standing debate in the protein-­‐‑folding field is whether unfolding rate

constants or folding rate constants correlate to the stability of a protein. FNIII domains all have the same ß sandwich structure but very different stabilities and amino acid sequences. Our study analyzed the kinetics of unfolding and folding and stabilities of eleven FNIII domains and our results show that folding rate constants for FNIII domains are relatively similar and the unfolding rates vary widely and correlate to stability. FN forms a fibrillar matrix and the FN-­‐‑FN interactions during matrix fibril formation are not known. FNI 1-­‐‑9 or the N-­‐‑ terminal region is indispensible for matrix formation and its major binding partner has been shown to be FNIII 2. Earlier work from our lab, using FRET analysis showed that the interaction of FNI 1-­‐‑9 with a destabilized FNIII 2 (missing the G strand, FNIII 2ΔG) reduces the FRET efficiency. This efficiency is restored in the presence of FUD (bacterial adhesion from S. pyogenes) that has been known to interact with FNI 1-­‐‑9 via a tandem ß zipper. In the present study we

use FRET analysis and a series of deletion mutants of FNIII 2ΔG to study the shortest fragment of FNIII 2ΔG that is required to bind FNI 1-­‐‑9. Our results presented here are qualitative and show that FNIII 2ΔC’EFG is the shortest fragment required to bind FNI 1-­‐‑9. Deletion of one more strand abolishes the interaction with FNI 1-­‐‑9.

Decoding Spontaneous Emotional States in the Human Brain.

Pattern classification of human brain activity provides unique insight into the neural underpinnings of diverse mental states. These multivariate tools have recently been used within the field of affective neuroscience to classify distributed patterns of brain activation evoked during emotion induction procedures. Here we assess whether neural models developed to discriminate among distinct emotion categories exhibit predictive validity in the absence of exteroceptive emotional stimulation. In two experiments, we show that spontaneous fluctuations in human resting-state brain activity can be decoded into categories of experience delineating unique emotional states that exhibit spatiotemporal coherence, covary with individual differences in mood and personality traits, and predict on-line, self-reported feelings. These findings validate objective, brain-based models of emotion and show how emotional states dynamically emerge from the activity of separable neural systems.

Fermion Mass Generation without Spontaneous Symmetry Breaking

The conventional mechanism of fermion mass generation in the Standard Model involves Spontaneous Symmetry Breaking (SSB). In this thesis, we study an alternate mechanism for the generation of fermion masses that does not require SSB, in the context of lattice field theories. Being inherently strongly coupled, this mechanism requires a non-perturbative approach like the lattice approach.

In order to explore this mechanism, we study a simple lattice model with a four-fermion interaction that has massless fermions at weak couplings and massive fermions at strong couplings, but without any spontaneous symmetry breaking. Prior work on this type of mass generation mechanism in 4D, was done long ago using either mean-field theory or Monte-Carlo calculations on small lattices. In this thesis, we have developed a new computational approach that enables us to perform large scale quantum Monte-Carlo calculations to study the phase structure of this theory. In 4D, our results confirm prior results, but differ in some quantitative details of the phase diagram. In contrast, in 3D, we discover a new second order critical point using calculations on lattices up to size $ 60^3$. Such large scale calculations are unprecedented. The presence of the critical point implies the existence of an alternate mechanism of fermion mass generation without any SSB, that could be of interest in continuum quantum field theory.