Does acute aerobic exercise enhance selective attention, working memory, and problem-solving abilities in Alzheimer's patients? A sex-based comparative study

IntroductionThe present study aimed to evaluate the effect of acute aerobic exercise on certain cognitive functions known to be affected by Alzheimer's disease (AD), with a particular emphasis on sex differences.MethodsA total of 53 patients, with a mean age of 70.54 ± 0.88 years and moderate AD, voluntarily participated in the study. Participants were randomly assigned to two groups: the experimental group (EG), which participated in a 20-min moderate-intensity cycling session (60% of the individual maximum target heart rate recorded at the end of the 6-min walk test); and the control group (CG), which participated in a 20-min reading activity. Cognitive abilities were assessed before and after the physical exercise or reading session using the Stroop test for selective attention, the forward and backward digit span test for working memory, and the Tower of Hanoi task for problem-solving abilities.ResultsAt baseline, both groups had comparable cognitive performance (p > 0.05 in all tests). Regardless of sex, aerobic acute exercise improved attention in the Stroop test (p < 0.001), enhanced memory performance in both forward (p < 0.001) and backward (p < 0.001) conditions, and reduced the time required to solve the problem in the Tower of Hanoi task (p < 0.001). No significant differences were observed in the number of movements. In contrast, the CG did not significantly improve after the reading session for any of the cognitive tasks (p > 0.05). Consequently, the EG recorded greater performance improvements than the CG in most cognitive tasks tested (p < 0.0001) after the intervention session.DiscussionThese findings demonstrate that, irrespective to sex, a single aerobic exercise session on an ergocycle can improve cognitive function in patients with moderate AD. The results suggest that acute aerobic exercise enhances cognitive function similarly in both female and male patients, indicating promising directions for inclusive therapeutic strategies

Modeling-based optimization approaches for the development of Anti- Agrobacterium tumefaciens activity using Streptomyces sp TN71

A new aerobic bacterium TN71 was isolated from Tunisian Saharan soil and has been selected for its antimicrobial activity against phytopathogenic bacteria. Based on cellular morphology, physiological characterization and phylogenetic analysis, this isolate has been assigned as Streptomyces sp. TN71 strain. In an attempt to increase its anti-Agrobacterium tumefaciens activity, GYM + S (glucose, yeast extract, malt extract and starch) medium was selected out of five different production media and the medium composition was optimized. Plackett-Burman design (PBD) was used to select starch, malt extract and glucose as parameters having significant effects on antibacterial activity and a Box-Behnken design was applied for further optimization. The analysis revealed that the optimum concentrations for anti-A. tumefaciens activity of the tested variables were 19.49 g/L for starch, 5.06 g/L for malt extract and 2.07 g/L for glucose. Several Artificial Neural Networks (ANN): the Multilayer perceptron (MLP) and the Radial basis function (RBF) were also constructed to predict anti-A. tumefaciens activity. The comparison between experimental with predicted outputs from ANN and Response Surface Methodology (RSM) were studied. ANN model presents an improvement of 12.36% in terms of determination coefficients of anti A. tumefaciens activity. To our knowledge, this is the first work reporting the statistical versus artificial intelligence based modeling for optimization of bioactive molecules against phytopathogen

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Effet d’une stimulation enrichie sur le fonctionnement cognitif de personnes Alzheimer à un stade modéré et des adultes présentant un déficit cognitif léger.

Objectif : L’objectif de cette thèse est d’évaluer l’effet de la combinaison de l’exercice physique (seul ou répété) et de l’exercice intellectuel sur le fonctionnement cognitif chez les patients Alzheimer à un stade modéré (ADM) et des participants ayant un déficit cognitif modéré léger (MCI). Méthodes : Soixante-dix-neuf patients ADM et 44 patients MCI ont participé à l’étude. Après un bilan neuropsychologique et une évaluation cardio-respiratoire, tous les patients ont été répartis en trois groupes. Les patients, constituant le groupe expérimental physique seul (MCI= 15 patients, ADM= 27 patients), ont effectué un exercice de pédalage sur ergocycle pendant vingt minutes. L’intensité de l’exercice était fixée à 60% de la fréquence cardiaque maximale, atteinte à la fin d’un test préalable de marche de 6 minutes. Les participants du groupe combiné (MCI= 15 patients, ADM= 25 patients) ont effectué le même programme du groupe physique mais avec un rajout simultané des jeux cognitifs pendant l’exercice à partir de la 3éme minute. Le groupe témoin (MCI= 14 patients, ADM= 26 patients) a eu une séance de lecture de 20 minutes, à la place de l’exercice de pédalage. Chez les sujets MCI et ADM, on a proposé l’exercice aérobie (cyclisme) combiné ou non avec des jeux cognitifs et contrasté à l’activité de lecture pour le groupe témoin. À cinq moments (avant l’exercice (à l’inclusion de l’étude), immédiatement après l’exercice, après un mois d’entrainement et après deux mois d’entrainement et après 4 semaines de l’arrêt de l’entrainement (4 semaines de repos)), les participants ont été soumis à trois tâches cognitives : test Stroop, test de la tour de Hanoi et test d’empan de chiffres à l’endroit et à l’envers pour évaluer respectivement la sensibilité aux interférences, la résolution de problèmes et la mémoire de travail. Résultats : La comparaison des performances obtenues avant et après l’exercice physique de pédalage a montré une amélioration significative pour les trois tâches proposées dans les groupes expérimentaux avec un effet plus important chez le groupe combiné des patients ADM et des patients MCI. En revanche, les performances cognitives du groupe témoin n’ont quasiment pas changé après la séance de lecture. Conclusion : Les résultats de la présente étude, comme les résultats des travaux rapportés, montrent l’impact bénéfique d’un exercice unique sur les performances cognitives chez des patients diagnostiqués ADM et des patients MCI. L’objectif étant de prévenir et / ou de ralentir le déclin cognitif dans la maladie d’Alzheimer, les résultats de notre étude sont prometteurs. Le caractère singulier de ces résultats réside dans le fait qu’une séance unique permet d’avoir un effet bénéfique. Notre étude longitudinale portant sur l’impact de l’exercice chronique de type aérobie a permis de cerner les effets à long terme sur cette population. Plus important, le rajout des jeux cognitifs à l’exercice physique (seul ou répété) potentialise cet effet positif chez les patients ADM et MCI. Cet effet est durable après une période de repos.Objective: The objective of this thesis is to test if combined physical and cognitive exercise (acute exercise or physical training) is associated with better outcomes, compared with aerobic training alone in individuals with mild cognitive impairment (MCI).and in Alzheimer's patients at a moderate stage (ADM).Methods: Forty-four MCI and seventy-nine patient ADM aged 65 to 75 years were randomly recruited to the study. After a neuropsychological assessment and a cardio-respiratory evaluation, all the patients were divided into three groups according to the task: aerobic exercises done alone (AT group, MCI = 15 patients, ADM = 27 patients) or combined with cognitive games presented on a screen (ACT group, MCI = 15 patients, ADM = 25 patients) and control group (CG group, MCI = 14 patients, ADM = 26 patients) who performed a reading task. Selective attention (Stroop), problem solving (Hanoi Tower) and working memory (Digit Span) tasks assessed cognitive performances at baseline, at baseline (pre-exercise), immediately after exercise (post-exercise), at 4th and 8th week of training, and after 1-month of rest. Results: For MCI and ADM patients, after the exercise, the participants’ attention in both the physical and combined groups improved for the Stroop, the forward and backward Digit Span tasks, as well as the time taken to solve the Tower of Hanoi, although no significant differences were found in the number of moves taken in the latter. By contrast, the control group did not show any significant improvement for most of the cognitive tasks after the reading session.For MCI patients, in all tasks, performances were (1) improved in combined condition and in aerobic condition compared to Control group. Moreover, (2) the combined procedure induced deepest improvement compared to aerobic condition. (3) There was no modification of performance with reading only (control group). (4) The observed improvement of performance in combined and aerobic groups lasted even after four weeks without exercises (W12). These results highlight the advantage of combining cognitive and physical tasks in order to obtain a long-lasting improvement of executive functions in MCI patients. Comparison of scores obtained in the two neuropsychological assessments (at the beginning and at the end of training) shows significant improvements after training even in the control group for depression evaluation. For ADM patients, the aerobic training improved cognitive performance and neuropsychological assessments. This improvement was enhanced by cognitive enrichment except attention, when compared with exercise alone. Four weeks after the end of training, the positive effect was still observed. By contrast, the control group did not show any significant improvement for most of the cognitive tasks.Conclusion: Current evidence suggests that acute aerobic exercise and regular aerobic training may help to improve cognitive functions in MCI and ADM patients. This improvement is enhanced when the exercise is combined with cognitive games and lasts even after four weeks without exercises. These results may be used for physical and mental activity recommendations in adults with MCI to slow cognitive decline and in patients with ADM to stabilize or maintain cognitive function. Safe and progressive types of exercises should be promoted among MCI and ADM patients

DESCRIPTION OF THE LACK OF COMPACTNESS IN ORLICZ SPACES AND APPLICATIONS

International audienceIn this paper, we investigate the lack of compactness of the Sobolev embedding of $H^1(\R^2)$ into the Orlicz space $L^{{\phi}_p}(\R^2)$ associated to the function ϕp defined by \phi_p(s):={\rm{e}^{s^2}}-\Sum_{k=0}^{p-1} \frac{s^{2k}}{k!}\cdot We also undertake the study of a nonlinear wave equation with exponential growth where the Orlicz norm ∥.∥Lϕp plays a crucial role. This study includes issues of global existence, scattering and qualitative study

Characterization of the lack of compactness of H 2 rad (R 4 ) into the Orlicz space

International audienceThis paper is devoted to the description of the lack of compactness of the Sobolev space H 2 rad (R 4) in the Orlicz space L(R 4). The approach that we adopt to establish this characterization is in the spirit of the one adopted in the case of H 1 rad (R 2) into the Orlicz space L(R 2) in [H. Bahouri, M. Majdoub and N. Masmoudi, On the lack of compactness in the 2D critical Sobolev embedding, J. Funct. Anal. 260 (2011) 208–252]

3D multimodal MRI brain glioma tumor and edema segmentation: a graph cut distribution matching approach.

International audienceThis study investigates a fast distribution-matching, data-driven algorithm for 3D multimodal MRI brain glioma tumor and edema segmentation in different modalities. We learn non-parametric model distributions which characterize the normal regions in the current data. Then, we state our segmentation problems as the optimization of several cost functions of the same form, each containing two terms: (i) a distribution matching prior, which evaluates a global similarity between distributions, and (ii) a smoothness prior to avoid the occurrence of small, isolated regions in the solution. Obtained following recent bound-relaxation results, the optima of the cost functions yield the complement of the tumor region or edema region in nearly real-time. Based on global rather than pixel wise information, the proposed algorithm does not require an external learning from a large, manually-segmented training set, as is the case of the existing methods. Therefore, the ensuing results are independent of the choice of a training set. Quantitative evaluations over the publicly available training and testing data set from the MICCAI multimodal brain tumor segmentation challenge (BraTS 2012) demonstrated that our algorithm yields a highly competitive performance for complete edema and tumor segmentation, among nine existing competing methods, with an interesting computing execution time (less than 0.5s per image)