Central memory CD4+ T cells are preferential targets of double infection by HIV-1.

BACKGROUND: Template switching between two distinct HIV-1 RNA genomes during reverse transcription gives rise to recombinant viruses that greatly expand the genetic diversity of HIV-1 and have adverse implications for drug resistance, immune escape, and vaccine design. Virions with two distinct genomes are produced exclusively from cells infected with two or more viruses, or 'doubly infected' cells. Previous studies have revealed higher than expected frequencies of doubly infected cells compared to frequencies based on chance alone, suggesting non-random enhancement of double infection. METHODS: We investigated double infection of unstimulated primary CD4+ T cells using reporter viruses carrying genes for different fluorescent proteins, EGFP and mCherry, combined with sophisticated modeling techniques based on Poisson distribution. Additionally, through the use of multiparameter flow cytometry we examined the susceptibility of naïve and memory subsets of CD4+ T cells to double infection by HIV. RESULTS: Using our double infection system, we confirm non-random enhancement of multiple infection events. Double infection of CD4+ T cells was not found to be a consequence of suboptimal provirus expression rescued by Tat in trans-as has been reported in cell lines-but rather due to a heterogeneous cell population in which only a fraction of primary peripheral blood CD4+ T cells are susceptible to HIV infection regardless of viral titer. Intriguingly, double infection of CD4+ T cells occurred preferentially in memory CD4+ T cells-particularly the central memory (TCM) subset-but was not a consequence of SAMHD1-mediated restriction of HIV infection in naïve cells. CONCLUSIONS: These findings reveal that double infection in primary CD4+ T cells is primarily a consequences of cellular heterogeneity and not rescue of suboptimal provirus expression by Tat in trans. Additionally, we report a previously unappreciated phenomenon of enhanced double infection within primary TCM cells and suggest that these long-lived cells may serve as an archive that drive ongoing viral recombination events in vivo.

Revitalising traditional Indian games: inclusive game adaptations for children with cerebral palsy.

BACKGROUND: Children with cerebral palsy (CP) present unique challenges to physical activity due to various factors. Despite the benefits of inclusive approaches and adapted physical education, low- and middle-income countries face specific barriers including environmental, equipment, personal, policy, social and professional barriers. Traditional Indian games, with their cultural significance and potential therapeutic benefits, offer a promising avenue for inclusive adaptations. At present we couldn't find any studies that explore's the method of adaptation of traditional Indian games for children with cerebral palsy of varying functional levels. PURPOSE: The aim of the study was to explore the adaptation of traditional Indian games for children with CP of varying functional levels. METHODS: Traditional Indian games were identified through ethnographic qualitative research, and adapted using the Delphi process involving experts from various fields. A total of 10 traditional games were selected based on their health benefits using an operationalised conceptual model. The CHANGE IT model of adapted physical activity was used to systematically adapt each game. Validation of the model was then performed on children with CP [a smaller sample size, n = 10] with different levels of functioning. RESULTS: The games varied in playing positions, surfaces and phases. Modifications included changes in game rules, play environment, equipment and time duration. The study validation through informal interview among the parents of CP children revealed that adapted traditional game protocol shown improvements in their children's activity levels and participation. CONCLUSIONS: While this is a preliminary exploration, no firm conclusion can be drawn. The model presented in this study lays the foundation for future randomised controlled trials to validate the effects of adapted traditional Indian games on children with cerebral palsy of different functional levels.

A low-cost feasible method of physical promotion in children with cerebral palsy can be part of physical education curriculum. Secondary benefits are expected to include manuals for teaching the traditional games to children by schools, parents and rehabilitation workers. Clear guidelines in the manuals will assist other professionals to replicate this study in various other settings. The manual will list methods undertaken for documentation and steps for adaptation. Using these guidelines, it is anticipated that other games can be similarly analysed and manuals can be created.Rehabilitation workers and physical education teachers would benefit greatly from this study. Open courses on documentation and adaptation can be created and offered through "Swayam" the open learning portal of the University Grants Commission, India. This might reach a large number of people.Dissemination by means of conducting conferences, workshops and by providing the documentation to the regional cultural society and folklore museum may spread the effectiveness of this study to reach maximum areas throughout India.

Multiscale modeling approach to acoustic emission during plastic deformation.

We address the long-standing problem of the origin of acoustic emission commonly observed during plastic deformation. We propose a framework to deal with the widely separated time scales of collective dislocation dynamics and elastic degrees of freedom to explain the nature of acoustic emission observed during the Portevin-Le Chatelier effect. The Ananthakrishna model is used as it explains most generic features of the phenomenon. Our results show that while acoustic emission bursts correlated with stress drops are well separated for the type C serrations, these bursts merge to form nearly continuous acoustic signals with overriding bursts for the propagating type A bands.

Listing of Indian Folk Games for Potential Therapeutic Benefits in Children with Neurodevelopmental Disability.

Background: India has a diverse cultural heritage, with a wealth of indigenous folk games that are culturally ingrained. Due to the ease of acquisition, low costs, and widespread acceptability, this form of games can be incorporated to facilitate and improve physical fitness among children with neurodevelopmental disabilities. Hence this study focuses on the analysis of the therapeutic benefits of traditional Indian folk games. Objective: To explore the therapeutic benefits of traditional Indian folk games. Methodology: Ten traditional Indian folk games were selected through purposive sampling and videotaped on skilled players. Each game was analyzed by two observers based on an operationalized conceptual model by using a six-point Likert scale. Results: Functional domains of the game have been identified and listed by using the operationalized conceptual model. Conclusion: Folk games encompass a variety of functions and can potentially be used for therapeutic purposes in children with neurodevelopmental disabilities.

Hidden order in crackling noise during peeling of an adhesive tape.

We address the longstanding problem of recovering dynamical information from noisy acoustic emission signals arising from peeling of an adhesive tape subject to constant traction velocity. Using the phase space reconstruction procedure we demonstrate the deterministic chaotic dynamics by establishing the existence of correlation dimension as also a positive Lyapunov exponent in a midrange of traction velocities. The results are explained on the basis of the model that also emphasizes the deterministic origin of acoustic emission by clarifying its connection to stick-slip dynamics.

Intermittent peel front dynamics and the crackling noise in an adhesive tape.

We report a comprehensive investigation of a model for peeling of an adhesive tape along with a nonlinear time series analysis of experimental acoustic emission signals in an effort to understand the origin of intermittent peeling of an adhesive tape and its connection to acoustic emission. The model represents the acoustic energy dissipated in terms of Rayleigh dissipation functional that depends on the local strain rate. We show that the nature of the peel front exhibits rich spatiotemporal patterns ranging from smooth, rugged, and stuck-peeled configurations that depend on three parameters, namely the ratio of inertial time scale of the tape mass to that of the roller, the dissipation coefficient, and the pull velocity. The stuck-peeled configurations are reminiscent of fibrillar peel front patterns observed in experiments. We show that while the intermittent peeling is controlled by the peel force function, the model acoustic energy dissipated depends on the nature of the peel front and its dynamical evolution. Even though the acoustic energy is a fully dynamical quantity, it can be quite noisy for a certain set of parameter values, suggesting the deterministic origin of acoustic emission in experiments. To verify this suggestion, we have carried out a dynamical analysis of experimental acoustic emission time series for a wide range of traction velocities. Our analysis shows an unambiguous presence of chaotic dynamics within a subinterval of pull speeds within the intermittent regime. Time-series analysis of the model acoustic energy signals is also found to be chaotic within a subinterval of pull speeds. Further, the model provides insight into several statistical and dynamical features of the experimental acoustic emission signals including the transition from burst-type acoustic emission to continuous-type with increasing pull velocity and the connection between acoustic emission and stick-slip dynamics. Finally, the model also offers an explanation for the recently observed feature that the duration of the slip phase can be less than that of the stick phase.

Modeling the complexity of acoustic emission during intermittent plastic deformation: Power laws and multifractal spectra.

Scale-invariant power-law distributions for acoustic emission signals are ubiquitous in several plastically deforming materials. However, power-law distributions for acoustic emission energies are reported in distinctly different plastically deforming situations such as hcp and fcc single and polycrystalline samples exhibiting smooth stress-strain curves and in dilute metallic alloys exhibiting discontinuous flow. This is surprising since the underlying dislocation mechanisms in these two types of deformations are very different. So far, there have been no models that predict the power-law statistics for discontinuous flow. Furthermore, the statistics of the acoustic emission signals in jerky flow is even more complex, requiring multifractal measures for a proper characterization. There has been no model that explains the complex statistics either. Here we address the problem of statistical characterization of the acoustic emission signals associated with the three types of the Portevin-Le Chatelier bands. Following our recently proposed general framework for calculating acoustic emission, we set up a wave equation for the elastic degrees of freedom with a plastic strain rate as a source term. The energy dissipated during acoustic emission is represented by the Rayleigh-dissipation function. Using the plastic strain rate obtained from the Ananthakrishna model for the Portevin-Le Chatelier effect, we compute the acoustic emission signals associated with the three Portevin-Le Chatelier bands and the Lüders-like band. The so-calculated acoustic emission signals are used for further statistical characterization. Our results show that the model predicts power-law statistics for all the acoustic emission signals associated with the three types of Portevin-Le Chatelier bands with the exponent values increasing with increasing strain rate. The calculated multifractal spectra corresponding to the acoustic emission signals associated with the three band types have a maximum spread for the type C bands and decreasing with types B and A. We further show that the acoustic emission signals associated with Lüders-like band also exhibit a power-law distribution and multifractality.

Influence of viscoelastic nature on the intermittent peel-front dynamics of adhesive tape.

We investigate the influence of viscoelastic nature of the adhesive on the intermittent peel front dynamics by extending a recently introduced model for peeling of an adhesive tape. As time and rate-dependent deformation of the adhesives are measured in stationary conditions, a crucial step in incorporating the viscoelastic effects applicable to unstable intermittent peel dynamics is the introduction of a dynamization scheme that eliminates the explicit time dependence in terms of dynamical variables. We find contrasting influences of viscoelastic contribution in different regions of tape mass, roller inertia, and pull velocity. As the model acoustic energy dissipated depends on the nature of the peel front and its dynamical evolution, the combined effect of the roller inertia and pull velocity makes the acoustic energy noisier for small tape mass and low-pull velocity while it is burstlike for low-tape mass, intermediate values of the roller inertia and high-pull velocity. The changes are quantified by calculating the largest Lyapunov exponent and analyzing the statistical distributions of the amplitudes and durations of the model acoustic energy signals. Both single and two stage power-law distributions are observed. Scaling relations between the exponents are derived which show that the exponents corresponding to large values of event sizes and durations are completely determined by those for small values. The scaling relations are found to be satisfied in all cases studied. Interestingly, we find only five types of model acoustic emission signals among multitude of possibilities of the peel front configurations.