72 research outputs found
Corrigendum to " Adenosine role in brain functions: Pathophysiological influence on Parkinson's disease and other brain disorders "
The authors regret that the 3rd affiliation for author Ahmed A. Moustafa had been inadvertently omitted. The complete affiliations of the authors are presented above. The authors would like to apologize for any inconvenience caused.Scopu
The prevalence of ptsd and depression among Gaza children
Purpose: The purpose of this study is to investigate the prevalence of posttraumatic distress disorder (PTSD) and depression among children in Gaza, Palestine. Methodology: This study assessed the psychological effects of the Israeli-Palestinian conflict on children in the Gaza Strip. 286 children aged 9-14 years old, who were exposed to a wide range of war events, were selected from the Gaza Strip to participate in this study. All participants conducted the following scales: the child PTSD Reaction Index(CPTSD-RI), Beck Depression Inventory (BDI), and the Arabic version for PTSD and depression assessment. Finding: The results show that the mean number of participants witnessing home destroyed and people killed was (88%) and home invasion (76%). Approximately 70% of the participants reported that they witnessed war violence against at least one of their family members. Further, 44 % of the children have a least one death in their family due to the Israeli invasion. Using t-tests, we found that significantly more females have both PTSD and depression than males. Approximately 32.8% of the participants met the criteria for severe depression, and 42.6 % met the criteria for PTSD. Implications: Our results suggest that it is imperative to provide intervention programs to treat PTSD and depression symptoms among children in Gaza. These programs should take into account the cultural and religious background of the participants. Originality: This investigation of the Israeli-Palestinian conflict has led to an increase in PTSD and depression symptoms among children in the Gaza Strip. - Hamza et al.Scopu
Effect of Monosodium Glutamate on the Digestibility of Different Nutrients Using Standardized Static In vitro Digestion Model
Monosodium glutamate (MSG) is a flavor enhancer and food additive with a unique umami taste. Due to its widespread use in humans, this study focused on the cytotoxicity, anti-diabetic effect, and interaction with protein digestion by performing a standardized static in vitro digestion model and lipid digestion by estimating free fatty acids released from 0.5 g of olive oil during intestinal lipolysis. The study showed that monosodium glutamate has an apparent cytotoxic effect on the Caco-2 cell line in a dose-dependent manner. MSG glutamate also showed low inhibitory activity on alpha-glucosidase enzyme even at high concentrations (16.3 % at 1800 ppm). By performing simulated in vitro digestion to study the interaction between MSG and protein digestion, followed by MTT study, total protein determination, and pH drop method, all results concluded that MSG affected proteolysis. Finally, the impact of MSG on lipolysis was studied through a free fatty acid release test. The results of the study demonstrated that MSG harmed fat digestibility in a concentration-dependent manner. As a result, it is essential to conduct further studies, especially in vivo studies, to determine the potential negative effects of MSG on human health
Smell your memories: Positive effect of odor exposure on recent and remote autobiographical memories in Alzheimer's disease
Introduction: There is a burgeoning interest in the effects of odor exposure on autobiographical memory in Alzheimer’s disease (AD). We pursued this line of research by assessing the effect of odor exposure on the retrieval of recent and remote memories in AD.
Method: Twenty-six patients with mild AD and 28 controls were tested in two conditions: with and without odor exposure. In each condition, participants were invited to retrieve two childhood memories, two adulthood memories, and two recent memories.
Results: Analysis showed that AD patients produced a higher number of and more specific childhood memories, adulthood memories, and recent memories after odor exposure than without odor.
Discussion: These findings demonstrate how odor exposure may alleviate anterograde and retrograde amnesia, at least when considering the ability of patients with mild AD to retrieve few recent or remote memories.The study was supported by the LABEX (excellence laboratory, program investment for the future); DISTALZ (Development of Innovative Strategies for a Transdisciplinary Approach to Alzheimer Disease); and EU Interreg 2 Seas Programme 2014- 2020 (co-funded by the European Regional Development Fund).Scopu
Maladaptive avoidance patterns in Parkinson's disease are exacerbated by symptoms of depression
Available online 11 January 2020Parkinson’s disease (PD) is a chronic, progressive neurodegenerative disorder, characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta. Given that dopamine is critically involved in learning and other cognitive processes, such as working memory, dopamine loss in PD has been linked both to learning abnormalities and to cognitive dysfunction more generally in the disease. It is unclear, however, whether avoidance behavior is impacted in PD. This is significant, as this type of instrumental behavior plays an important role in both decision-making and emotional (dys) function. Consequently, the aim of the present study was to examine avoidance learning and operant extinction in PD using a computer-based task. On this task, participants control a spaceship and attempt to shoot an enemy spaceship to gain points. They also learn to hide in safe areas to protect from (i.e., avoid) aversive events (on-screen explosions and point loss). The results showed that patients with PD (N = 25) acquired an avoidance response during aversive periods to the same extent as healthy age-matched controls (N = 19); however, patients demonstrated greater hiding during safe periods not associated with aversive events, which could represent maladaptive generalization of the avoidance response. Furthermore, this impairment was more pronounced during the extinction phase, and in patients who reported higher levels of depression. These results demonstrate for the first time that PD is associated with maladaptive avoidance patterns, which could possibly contribute to the emergence of depression in the disease.Jony Sheynin, Irina Baetu, Lyndsey E. Collins-Praino, Catherine E. Myers, Robyn Winwood-Smith, Ahmed A. Moustaf
Computational investigation of mechanistic insights of Aβ42 interactions against extracellular domain of nAChRα7 in Alzheimer's disease
Aim: Amyloid beta (Aβ) 1-42, which is a basic constituent of amyloid plaques, binds with extracellular transmembrane receptor nicotine acetylcholine receptor α7 (nAChRα7) in Alzheimer’s disease.
Materials and Methods: In the current study, a computational approach was employed to explore the active binding sites of nAChRα7 through Aβ 1–42 interactions and their involvement in the activation of downstream signalling pathways. Sequential and structural analyses were performed on the extracellular part of nAChRα7 to identify its core active binding site.
Results: Results showed that a conserved residual pattern and well superimposed structures were observed in all nAChRs proteins. Molecular docking servers were used to predict the common interactive residues in nAChRα7 and Aβ1–42 proteins. The docking profile results showed some common interactive residues such as Glu22, Ala42 and Trp171 may consider as the active key player in the activation of downstream signalling pathways. Moreover, the signal communication and receiving efficacy of best-docked complexes was checked through DynOmic online server. Furthermore, the results from molecular dynamic simulation experiment showed the stability of nAChRα7. The generated root mean square deviations and fluctuations (RMSD/F), solvent accessible surface area (SASA) and radius of gyration (Rg) graphs of nAChRα7 also showed its backbone stability and compactness, respectively.
Conclusion: Taken together, our predicted results intimated the structural insight on the molecular interactions of beta amyloid protein involved in the activation of nAChRα7 receptor. In future, a better understanding of nAChRα7 and their interconnected proteins signalling cascade may be consider as target to cure Alzheimer’s disease.This was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03034948).Scopu
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
Quel rôle peut-on imputer aux banques à charte canadiennes dans la transmission des chocs monétaires des années quatre-vingt?
Cette recherche s’inscrit dans la foulée de nombreux travaux entrepris suite aux publications de Bernanke et Blinder (1988, 1992) ayant remis à l’avant-plan le rôle joué par le système bancaire dans la transmission de la politique monétaire. Nous proposons d’examiner la dynamique inhérente à certains postes du bilan des banques à charte canadiennes suite aux mouvement des principaux taux d’intérêt, habituellement jugés révélateurs des conditions monétaires du moment. Pour ce faire, nous avons recours à un modèle VAR hebdomadaire comportant à la fois, des éléments de l’actif et du passif des banques ainsi que les taux de rendement associés à divers instruments financiers. Cependant, dans le but de bien encadrer cette analyse, nous développons un modèle formel du comportement d’une banque où les seuls changements aux postes de son bilan suite aux mouvements de taux d’intérêt sont dictés par des ajustements de portefeuille visant à tirer avantage des écarts se creusant entre ceux-ci. Ce modèle théorique est soumis aux variations de taux d’intérêt issues du modèle empirique VAR. Les mouvements observés aux postes du bilan de cette banque « témoin » fournissent un guide utile permettant d’interpréter de façon éclairée les résultats empiriques obtenus. À cet égard, l’exercice proposé montre qu’il est possible d’établir un parallèle assez étroit entre l’évolution des postes du bilan de la banque hypothétique et celle captée par le modèle VAR et ainsi apporte un certain support à l’approche traditionnelle sur le rôle joué par les banques dans la transmission des chocs monétaires.This paper can be seen as a contribution to a growing literature initiated by Bernanke and Blinder (1988, 1992) which have examined the role played by the banking system in the transmission of monetary policy. We propose to study the dynamic behaviour of the balance sheet of Canadian chartered banks following a shock to some key interest rates which are good indicators of the prevailing monetary conditions. More specifically, we estimate a weekly VAR model which comprises key asset and liabilities elements as well as rates of return on major financial instruments. However, to guide this empirical inquiry, we set up a model of a representative bank which adjusts its balance sheet elements according to the interest rate spreads arising in the financial markets. This theoretical model is then subjected to the same interest rate shocks than those imposed on the VAR model: the adjustments observed in this laboratory will prove quite useful to assess the significance of the empirical results uncovered by the VAR model. Overall, we find that both approaches give rise to quite similar dynamic responses which tends to support the traditional role of the banking sector in the transmission of monetary policy
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
Dynamic communications between GABA A switch, local connectivity, and synapses during cortical development: A computational study
Several factors regulate cortical development, such as changes in local connectivity and the influences of dynamical synapses. In this study, we simulated various factors affecting the regulation of neural network activity during cortical development. Previous studies have shown that during early cortical development, the reversal potential of GABA A shifts from depolarizing to hyperpolarizing. Here we provide the first integrative computational model to simulate the combined effects of these factors in a unified framework (building on our prior work: Khalil et al., 2017a,b). In the current study, we extend our model to monitor firing activity in response to the excitatory action of GABA A . Precisely, we created a Spiking Neural Network model that included certain biophysical parameters for lateral connectivity (distance between adjacent neurons) and nearby local connectivity (complex connections involving those between neuronal groups). We simulated different network scenarios (for immature and mature conditions) based on these biophysical parameters. Then, we implemented two forms of Short-term synaptic plasticity (depression and facilitation). Each form has two distinct kinds according to its synaptic time constant value. Finally, in both sets of networks, we compared firing rate activity responses before and after simulating dynamical synapses. Based on simulation results, we found that the modulation effect of dynamical synapses for evaluating and shaping the firing activity of the neural network is strongly dependent on the physiological state of GABA A . Moreover, the STP mechanism acts differently in every network scenario, mirroring the crucial modulating roles of these critical parameters during cortical development. Clinical implications for pathological alterations of GABAergic signaling in neurological and psychiatric disorders are discussed. ? 2018 Khalil, Karim, Khedr, Moftah and Moustafa.KA 4267/3-1 Deutsche ForschungsgemeinschaftScopu
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