A connectionist perspective of the transition from Face-to-Face to online teaching in Higher Education

Existing research shows a slow transition to online education by many university teaching staff. A mixed methods approach is used to survey teacher educators in three jurisdictions in the UK who have made the transition to online teaching, followed by focus group and individual interviews to triangulate the data. The eight tenets of connectivism are used as a lens for analysis. Findings reveal sound pedagogical reasons for the limited choice of online tools and tutors highlight two elements, namely, self-fulfilment and their desire to continually develop as an educator, as the rationale for adopting informal professional development in the 21st century.

Ischemic A/D transition of mitochondrial complex I and its role in ROS generation

Mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a key enzyme in cellular energy metabolism and provides approximately 40% of the proton-motive force that is utilized during mitochondrial ATP production. The dysregulation of complex I function – either genetically, pharmacologically, or metabolically induced – has severe pathophysiological consequences that often involve an imbalance in the production of reactive oxygen species (ROS). Slow transition of the active (A) enzyme to the deactive, dormant (D) form takes place during ischemia in metabolically active organs such as the heart and brain. The reactivation of complex I occurs upon reoxygenation of ischemic tissue, a process that is usually accompanied by an increase in cellular ROS production. Complex I in the D-form serves as a protective mechanism preventing the oxidative burst upon reperfusion. Conversely, however, the D-form is more vulnerable to oxidative/nitrosative damage. Understanding the so-called active/deactive (A/D) transition may contribute to the development of new therapeutic interventions for conditions like stroke, cardiac infarction, and other ischemia-associated pathologies. In this review, we summarize current knowledge on the mechanism of A/D transition of mitochondrial complex I considering recently available structural data and site-specific labeling experiments. In addition, this review discusses in detail the impact of the A/D transition on ROS production by complex I and the S-nitrosation of a critical cysteine residue of subunit ND3 as a strategy to prevent oxidative damage and tissue damage during ischemia–reperfusion injury.

Fragment and vesicle structures in sonicated dispersions of dioctadecyldimethylammonium bromide

Dynamic light scattering has been used to investigate sonicated aqueous dispersions of dioctadecyldimethylammonium bromide (DODAB). The hydrodynamic radius (R-H) of the scattering particles and the mean scattering intensity (I) have been monitored as functions of the DODAB concentration and temperature (T). In the dilute regime, the relaxation time distribution of the sonicated dispersion of DODAB is bimodal with the slow mode dominating the distribution. The slow and fast modes are respectively characteristic of vesicles and bilayer fragments with R-H values of 22 and 8.5 nm (25 degrees C) and 20 and 6 nm (50 degrees C), respectively. The total scattered intensity initially decreased with temperature up to 45 degrees C (T-c), above which it was constant; identical behavior was observed for the slow mode intensity, but the fast mode intensity was constant with temperature change, showing that T-c is a property of the vesicles and not of the bilayer fragments. At T-c the slow vesicle mode becomes narrower whereas the fast fragment mode shows no change. on aging, the dispersion showed a slow transition from bimodal to a rather broad single-modal relaxation time distribution. The corresponding R-H was 33.8 nm when measured 10 months after preparation. These results suggest that aqueous sonicated dispersions of DODAB are metastable.

Order-Disorder Transitions Govern Kinetic Cooperativity and Allostery of Monomeric Human Glucokinase

Glucokinase (GCK) catalyzes the rate-limiting step of glucose catabolism in the pancreas, where it functions as the body's principal glucose sensor. GCK dysfunction leads to several potentially fatal diseases including maturity-onset diabetes of the young type II (MODY-II) and persistent hypoglycemic hyperinsulinemia of infancy (PHHI). GCK maintains glucose homeostasis by displaying a sigmoidal kinetic response to increasing blood glucose levels. This positive cooperativity is unique because the enzyme functions exclusively as a monomer and possesses only a single glucose binding site. Despite nearly a half century of research, the mechanistic basis for GCK's homotropic allostery remains unresolved. Here we explain GCK cooperativity in terms of large-scale, glucose-mediated disorder-order transitions using 17 isotopically labeled isoleucine methyl groups and three tryptophan side chains as sensitive nuclear magnetic resonance (NMR) probes. We find that the small domain of unliganded GCK is intrinsically disordered and samples a broad conformational ensemble. We also demonstrate that small-molecule diabetes therapeutic agents and hyperinsulinemia-associated GCK mutations share a strikingly similar activation mechanism, characterized by a population shift toward a more narrow, well-ordered ensemble resembling the glucose-bound conformation. Our results support a model in which GCK generates its cooperative kinetic response at low glucose concentrations by using a millisecond disorder-order cycle of the small domain as a "time-delay loop," which is bypassed at high glucose concentrations, providing a unique mechanism to allosterically regulate the activity of human GCK under physiological conditions.

A SOTERIOLOGIA SOCIAL DE JOHN WESLEY com consideração especial de seus aspectos comunitários, sinergéticos e públicos

Este estudo investiga os elementos da soteriologia de John Wesley e seus aspectos dinamizantes. Em vez de favorecer um determinado período da vida de Jonh Wesley, a biografia teológica de John Wesley é desenvolvida a partir do conceito da sedimentação de experiência. Dessa forma, a theologia viatorum de John Wesley é desenvolvida com foco nos seus elementos transversais e os crescentes desdobramentos dos mesmos segundo os seus aspectos comunitários, sinergéticos e públicos. Segundo esta tese, a theologia viatorum de John Wesley ganha em profundidade e vitalidade com a sua crescente e consciente aprendizagem e compromisso com o povo inglês e, em especial, com os pobres da Inglaterra. Acompanhado por uma cuidadosa auto-análise, Wesley parte para a análise do efeito de diversas soteriologias dos seus dias no cotidiano, as quais são marcadas pela demorada transição entre a época medieval e a modernidade. Surge uma re-construção característica da soteriologia, designado por nós como soteriologia social. Entendemos esta soteriologia social como o eixo principal da teologia de John Wesley que se manifesta numa típica antropologia, cristologia, pneumatologia, escatologia e eclesiologia soteriológica. Os aspectos comunitários, sinergéticos e públicos desta soteriologia social são vistos e desenvolvidos por Wesley a partir da auto-experiência e da convivência com o povo, suas dinâmicas, sua cultura, suas necessidades e suas competências. Tais aspectos levam, passo a passo, a uma práxis que começa a contemplar o entrelaçamento entre a reforma da igreja, da nação e a transformação de pessoas. Este movimento é comotivado por um horizonte soterioló gico utópico que prevê a continuação da theologia viatorum até na transformação do cosmo inteiro. A soteriologia social é parecida com a um tecido que acompanha a topografia socio-econômica e religiosa da época, procurando caminhos para a superação dos seus impasses, da sua desesperança e irresponsabilidade em relação aos pobres.(AU)

A SOTERIOLOGIA SOCIAL DE JOHN WESLEY com consideração especial de seus aspectos comunitários, sinergéticos e públicos

Este estudo investiga os elementos da soteriologia de John Wesley e seus aspectos dinamizantes. Em vez de favorecer um determinado período da vida de Jonh Wesley, a biografia teológica de John Wesley é desenvolvida a partir do conceito da sedimentação de experiência. Dessa forma, a theologia viatorum de John Wesley é desenvolvida com foco nos seus elementos transversais e os crescentes desdobramentos dos mesmos segundo os seus aspectos comunitários, sinergéticos e públicos. Segundo esta tese, a theologia viatorum de John Wesley ganha em profundidade e vitalidade com a sua crescente e consciente aprendizagem e compromisso com o povo inglês e, em especial, com os pobres da Inglaterra. Acompanhado por uma cuidadosa auto-análise, Wesley parte para a análise do efeito de diversas soteriologias dos seus dias no cotidiano, as quais são marcadas pela demorada transição entre a época medieval e a modernidade. Surge uma re-construção característica da soteriologia, designado por nós como soteriologia social. Entendemos esta soteriologia social como o eixo principal da teologia de John Wesley que se manifesta numa típica antropologia, cristologia, pneumatologia, escatologia e eclesiologia soteriológica. Os aspectos comunitários, sinergéticos e públicos desta soteriologia social são vistos e desenvolvidos por Wesley a partir da auto-experiência e da convivência com o povo, suas dinâmicas, sua cultura, suas necessidades e suas competências. Tais aspectos levam, passo a passo, a uma práxis que começa a contemplar o entrelaçamento entre a reforma da igreja, da nação e a transformação de pessoas. Este movimento é comotivado por um horizonte soterioló gico utópico que prevê a continuação da theologia viatorum até na transformação do cosmo inteiro. A soteriologia social é parecida com a um tecido que acompanha a topografia socio-econômica e religiosa da época, procurando caminhos para a superação dos seus impasses, da sua desesperança e irresponsabilidade em relação aos pobres.(AU)

Magnesium-dependent folding of self-splicing RNA: Exploring the link between cooperativity, thermodynamics, and kinetics

Folding of the Tetrahymena self-splicing RNA into its active conformation involves a set of discrete intermediate states. The Mg2+-dependent equilibrium transition from the intermediates to the native structure is more cooperative than the formation of the intermediates from the unfolded states. We show that the degree of cooperativity is linked to the free energy of each transition and that the rate of the slow transition from the intermediates to the native state decreases exponentially with increasing Mg2+ concentration. Monovalent salts, which stabilize the folded RNA nonspecifically, induce states that fold in less than 30 s after Mg2+ is added to the RNA. A simple model is proposed that predicts the folding kinetics from the Mg2+-dependent change in the relative stabilities of the intermediate and native states.

A SOTERIOLOGIA SOCIAL DE JOHN WESLEY com consideração especial de seus aspectos comunitários, sinergéticos e públicos

Este estudo investiga os elementos da soteriologia de John Wesley e seus aspectos dinamizantes. Em vez de favorecer um determinado período da vida de Jonh Wesley, a biografia teológica de John Wesley é desenvolvida a partir do conceito da sedimentação de experiência. Dessa forma, a theologia viatorum de John Wesley é desenvolvida com foco nos seus elementos transversais e os crescentes desdobramentos dos mesmos segundo os seus aspectos comunitários, sinergéticos e públicos. Segundo esta tese, a theologia viatorum de John Wesley ganha em profundidade e vitalidade com a sua crescente e consciente aprendizagem e compromisso com o povo inglês e, em especial, com os pobres da Inglaterra. Acompanhado por uma cuidadosa auto-análise, Wesley parte para a análise do efeito de diversas soteriologias dos seus dias no cotidiano, as quais são marcadas pela demorada transição entre a época medieval e a modernidade. Surge uma re-construção característica da soteriologia, designado por nós como soteriologia social. Entendemos esta soteriologia social como o eixo principal da teologia de John Wesley que se manifesta numa típica antropologia, cristologia, pneumatologia, escatologia e eclesiologia soteriológica. Os aspectos comunitários, sinergéticos e públicos desta soteriologia social são vistos e desenvolvidos por Wesley a partir da auto-experiência e da convivência com o povo, suas dinâmicas, sua cultura, suas necessidades e suas competências. Tais aspectos levam, passo a passo, a uma práxis que começa a contemplar o entrelaçamento entre a reforma da igreja, da nação e a transformação de pessoas. Este movimento é comotivado por um horizonte soterioló gico utópico que prevê a continuação da theologia viatorum até na transformação do cosmo inteiro. A soteriologia social é parecida com a um tecido que acompanha a topografia socio-econômica e religiosa da época, procurando caminhos para a superação dos seus impasses, da sua desesperança e irresponsabilidade em relação aos pobres.(AU)

Identification of residues linked to the slow-->fast transition of thrombin.

Residues energetically linked to the allosteric transition of thrombin from its anticoagulant slow form to the procoagulant fast form have been identified by site-directed mutagenesis. The energetics of recognition by the two forms of the enzyme were probed by using a synthetic chromogenic substrate, fibrinogen, and hirudin. The thrombin residues E39, W60d, E192, D221, and D222 are linked to the slow-->fast transition and are part of an "allosteric core" through which events originating at the Na+ binding loop propagate to other regions of the enzyme. The thrombin residues Y76, W96, W148, and R173 lie at the periphery of the allosteric core, affect recognition of fibrinogen and hirudin to the same extent in both forms, and are not linked to the slow-->fast transition.

Universality in the fast orientational relaxation near isotropic-nematic transition

Detailed molecular dynamics simulations of Lennard-Jones ellipsoids have been carried out to investigate the emergence of criticality in the single-particle orientational relaxation near the isotropic-nematic (IN) phase transition. The simulations show a sudden appearance of a power-law behavior in the decay of the second-rank orientational relaxation as the IN transition is approached. The simulated value of the power-law exponent is 0.56, which is larger than the mean-field value (0.5) but less than the observed value (0.63) and may be due to the finite size of the simulated system. The decay of the first-rank orientational time correlation function, on the other hand, is nearly exponential but its decay becomes very slow near the isotropic-nematic transition, The zero-frequency rotational friction, calculated from the simulated angular Velocity correlation function, shows a marked increase near the IN transition.

Energy landscape view of phase transitions and slow dynamics in thermotropic liquid crystals

Thermotropic liquid crystals are known to display rich phase behavior on temperature variation. Although the nematic phase is orientationally ordered but translationally disordered, a smectic phase is characterized by the appearance of a partial translational order in addition to a further increase in orientational order. In an attempt to understand the interplay between orientational and translational order in the mesophases that thermotropic liquid crystals typically exhibit upon cooling from the high-temperature isotropic phase, we investigate the potential energy landscapes of a family of model liquid crystalline systems. The configurations of the system corresponding to the local potential energy minima, known as the inherent structures, are determined from computer simulations across the mesophases. We find that the depth of the potential energy minima explored by the system along an isochor grows through the nematic phase as temperature drops in contrast to its insensitivity to temperature in the isotropic and smectic phases. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures; the inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the isotropic-nematic transition. We find that this breakdown occurs at a temperature below which the system explores increasingly deeper potential energy minima.

Collective Effects on Single Particle Orientational Relaxation in Slow Dipolar Liquids

Theoretical and computer simulation studies of orientational relaxation in dense molecular liquids are presented. The emphasis of the study is to understand the effects of collective orientational relaxation on the single-particle orientational dynamics. The theoretical analysis is based on a recently developed molecular hydrodynamic theory which allows a self-consistent description of both the collective and the single-particle orientational relaxation. The molecular hydrodynamic theory can be used to derive a relation between the memory function for the collective orientational correlation function and the frequency-dependent dielectric function. A novel feature of the present work is the demonstration that this collective memory function is significantly different from the single-particle rotational friction. However, a microscopic expression for the single-particle rotational friction can be derived from the molecular hydrodynamic theory where the collective memory function can be used to obtain the single-particle orientational friction. This procedure allows, us to calculate the single-particle orientational correlation function near the alpha-beta transition in the supercooled liquid. The calculated correlation function shows an interesting bimodal decay below the bifurcation temperature as the glass transition is approached from above. Brownian dynamics simulations have been carried out to check the validity of the above procedure of translating the memory function from the dielectric relaxation data. We have also investigated the following two issues important in understanding the orientational relaxation in slow liquids. First, we present an analysis of the ''orientational caging'' of translational motion. The value of the translational friction is found to be altered significantly by the orientational caging. Second, we address the question of the rank dependence of the dielectric friction using both simulation and the molecular hydrodynamic theory.

Comparison of the ultrafast to slow time scale dynamics of three liquid crystals in the isotropic phase

The dynamics of three liquid crystals, 4'(pentyloxy)-4-biphenylcarbonitrile (5-OCB), 4'-pentyl-4-biphenylcarbonitrile (5-CB), and 1-isothiocyanato-(4-propylcyclohexyl)benzene (3-CHBT), are investigated from very short time (similar to1 ps) to very long time (>100 ns) as a function of temperature using optical heterodyne detected optical Kerr effect experiments. For all three liquid crystals, the data decay exponentially only on the longest time scale (> several ns). The temperature dependence of the long time scale exponential decays is described well by the Landau-de Gennes theory of the randomization of pseudonematic domains that exist in the isotropic phase of liquid crystals near the isotropic to nematic phase transition. At short time, all three liquid crystals display power law decays. Over the full range of times, the data for all three liquid crystals are fit with a model function that contains a short time power law. The power law exponents for the three liquid crystals range between 0.63 and 0.76, and the power law exponents are temperature independent over a wide range of temperatures. Integration of the fitting function gives the empirical polarizability-polarizability (orientational) correlation function. A preliminary theoretical treatment of collective motions yields a correlation function that indicates that the data can decay as a power law at short times. The power law component of the decay reflects intradomain dynamics. (C) 2002 American Institute of Physics.

Hydrogen-bond dynamics near a micellar surface: Origin of the universal slow relaxation at complex aqueous interfaces

The dynamics of hydrogen bonds among water molecules themselves and with the polar head groups (PHG) at a micellar surface have been investigated by long molecular dynamics simulations. The lifetime of the hydrogen bond between a PHG and a water molecule is found to be much longer than that between any two water molecules, and is likely to be a general feature of hydrophilic surfaces of organized assemblies. Analyses of individual water trajectories suggest that water molecules can remain bound to the micellar surface for more than 100 ps. The activation energy for such a transition from the bound to a free state for the water molecules is estimated to be about 3.5 kcal/mol.