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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

The impact of the COVID-19 pandemic on mental health of children and adolescents

Srivastava, Gautam January 2020 (has links)
The rapidly spreading pandemic of SARS-CoV-2 (COVID-19) infection with high morbidity and mortality has overwhelmed the global healthcare services. With mysterious origins and the capacity of affecting multiple types of tissues, SARS-CoV-2 has baffled many scientists - which has posed great challenges in the development of pharmaceutical treatments and preventions (i.e., vaccination). The COVID-19 pandemic has also led to a slew of non-pharmaceutical interventions (NPIs) to slow down the spread of the virus. The sudden imposition of these NPIs including social distancing, lock-down, school closures, isolation, and quarantine of suspected cases or contacts, has greatly affected the mental health of children and adolescents. Concerns about the impact of these NPIs on mental health, especially for vulnerable populations such as children and adolescents, have emerged. This study discusses several different aspects of the impact of the COVID-19 pandemic on the mental health of children and adolescents.Accumulating evidence has shown that the vast majority of children and adolescents exposed to the SARS-CoV-2 virus are asymptomatic, although few cases turned unfortunately severely ill. The genomics, microbiology, and biochemistry of this novel coronavirus reveal several peculiarities, making it a tough entity. The profound impact of social distancing along with the closure of schools, parks, and other recreational activities on the delicate minds of children and adolescents makes them irritable, angry, and rebellious. This assumes a major challenge in children with mental health issues or in those with special needs. Lock-down, quarantine and isolation further complicate the mental health issues and are discussed along with remedial measures. The impact of an already overwhelmed medical care system on the mental healthcare quality can be profound and needs a specially chartered approach by the psychiatrists supplementing the COVID-19 control activities. Children/adolescents with neuropsychiatric issues need special care, as they have abnormal impulsive behaviour and actions such as running away, unhygienic acts, spitting etc. All these mental health issues in children and adolescents, who form a sizable population of the society and are the future of the planet, forms the subject matter of this work. Thus, all programmes of COVID-19 control must simultaneously address these important mental health issues of children and adolescents to prevent this ‘parallel pandemic’ of psychiatric disorders. The latter may persist much longer and prove equally challenging and costly.
352

Metodología para evaluar el nivel de protección respiratoria de mascarillas y respiradores ante partículas similares a las que transmiten el SARS-CoV-2 / Methodology for evaluating the level of respiratory protection of masks and respirators against particles similar to those that transmit SARS-COV-2

Chavez-Ruiz, Manuel, Rueda-Torres, Lenin, Ruffner-Camargo, Betsabé, Bellido-Achahui, Cristofer 05 October 2021 (has links)
Objetivo: Desarrollar una metodología para evaluar el nivel de protección respiratoria de respiradores, mascarillas quirúrgicas y mascarillas comunitarias que usa la población peruana, usando partículas de un tamaño similar a las que contienen al virus activo del SARS-CoV-2. Materiales y métodos: Se ha determinado una relación lineal directa entre el logaritmo de la concentración de partículas suspendidas en aire y el tiempo transcurrido; por lo cual es posible comparar la cantidad de partículas internas y externas a la mascarilla o respirador en un mismo periodo y conocer el porcentaje de protección respiratoria de cada muestra evaluada. Resultados: Se ha logrado implementar una metodología para evaluar el nivel de protección respiratoria ante aerosoles menores a 5,0 μm. Asimismo, el empleo de accesorios como ligas o ajustadores detrás de cabeza y nuca, y el uso de clips nasales robustos, incrementan significativamente el nivel de protección respiratoria ante partículas con alta probabilidad de contener al SARS-CoV-2. Conclusiones: Se observa una concordancia entre los valores de protección respiratoria obtenidos y los esperados, considerando el nivel de filtración del material empleado de cada mascarilla quirúrgica o respirador, y su nivel de ajuste. Se observó un incremento significativo en los niveles de protección respiratoria. / Objective: To develop a methodology for evaluating the level of respiratory protection provided by res- pirators, surgical masks and community face masks used by the Peruvian population; protection was evaluated against particles of a size similar to those containing active SARS-CoV-2 virus. Materials and methods: A direct linear relationship has been determined between the logarithm of the concentration of airborne particles and the elapsed time; thus, it is possible to compare the quantity of particles inside and outside of the mask or respirator in the same time period, as well as to obtain the percentage of re- spiratory protection for each evaluated sample. Results: A methodology was established to evaluate the level of respiratory protection against aerosols smaller than 5.0 μm. Also, the use of accessories such as garters or adjusters behind the head and neck, and the use of strong nasal clips, significantly increased the level of respiratory protection against particles with a high probability of containing SARS-CoV-2. Conclusions: We found concordance between the obtained respiratory protection values and those ex- pected, considering the filtration level of the material used for each surgical mask or resp s well as the tightness. A significant increase in the levels of respiratory protection was observed.
353

Disease Tolerance, Epigenetic Inheritance, and Surviving Pathogenic Viral Infections

Silverstein, Noah J. 18 August 2021 (has links)
Health is often defined in terms of absence of disease or pathological processes, but this is a definition of exclusion and incomplete. For example, SARS-CoV-2 viral load does not reliably predict disease severity, and so individuals must vary in their ability to control inflammation and maintain normal tissue homeostasis. This host defense strategy is called disease tolerance, and better understanding of disease tolerance mechanisms could change the way that we treat disease and work to maintain health. The first project presented in this dissertation found that after accounting for effects of age and sex, innate lymphoid cells (ILCs), but not T cells, were lower in adults and children sick with COVID-19 or MIS-C, independent of lymphopenia. Furthermore, abundance of ILCs, but not of T cells, correlated inversely with disease severity. These blood ILCs were shown to produce amphiregulin, a protein implicated in disease tolerance and tissue homeostasis, and the percentage of amphiregulin-producing ILCs was lower in males. These results suggest that, by promoting disease tolerance, homeostatic ILCs decrease morbidity and mortality associated with SARS-CoV-2 infection, and that lower ILC abundance accounts for increased COVID-19 severity with age and in males. The second project describes a novel mouse model of epigenetic inheritance wherein paternal influenza A virus (IAV) infection results in less severe influenza disease in IAV infected offspring. This offspring phenotype was not attributable to differences in viral load, indicating a possible difference in disease tolerance. Paternal caloric deprivation decreased, and influenza B virus infection increased, offspring influenza disease severity, and in vitro fertilization demonstrated sperm are sufficient to transfer IAV-associated epigenetic inheritance phenotypes. These findings represent a foundation for further work that, by continuing to elucidate the mechanisms of disease tolerance and epigenetic inheritance, could provide novel therapeutic interventions to help promote and maintain health.
354

Étude et développement d'un procédé de traitement des odeurs par oxydation à l'ozone : application aux effluents gazeux d'usines de production de superphosphate / Study and development of an odor treatment process by ozone oxidation : application to gaseous effluents from superphosphate production plants

Vitola Pasetto, Leticia 18 July 2019 (has links)
Dans le procédé de production d’engrais à base de superphosphate, l’attaque de la roche phosphatée par l’acide sulfurique génère des sous-produits gazeux odorants. Bien que leurs émissions se situent dans les limites réglementaires, les usines d’engrais à base de superphosphate sont susceptibles de causer des nuisances olfactives pour les riverains. Cette thèse propose d’étudier la faisabilité d’un procédé de traitement des odeurs par l’ozonation en phase gazeuse homogène. Une première étape de priorisation des composés chimiques ayant le potentiel odorant le plus important a été réalisée. Ce classement a été effectué à partir d’un rapport technique fourni par notre partenaire industriel basé sur une campagne de mesure olfactométrique et de caractérisation chimique des gaz émis par la cheminée d’une usine de production des engrais superphosphate. À partir du calcul de la valeur d’activité odorante (OAV), deux familles de composés ont été ciblées : les composés soufrés – représentés par le sulfure d’hydrogène (H2S), le sulfure d’éthylméthyle (MES) et le disulfure de diméthyle (DMDS) – et les aldéhydes (représentés par le propanal et le butanal). Deux techniques analytiques (GC/FID et SIFT/MS) ont été mises en œuvre afin d’évaluer les performances d’élimination de ces composés, la difficulté d'analyser une matrice gazeuse contenant de l'ozone ayant été mise en évidence. Ainsi, une interférence de l'ozone sur l'analyse des aldéhydes par GC/FID a été identifiée. La technique SIFT/MS a, quant à elle, nécessité un développement important. L’ozonation d’effluents gazeux modèles a été réalisée en suivant l’élimination des composés cibles dans différentes conditions de fonctionnement (temps de résidence, température du réacteur, concentration en ozone et taux d’humidité) dans un domaine expérimental compatible avec les contraintes industrielles. Les composés soufrés ont présenté des taux d’élimination élevés, particulièrement dans le cas de H2S, dont les conversions ont atteint environ 80%. Les monosulfures (MES) et disulfures organiques (DMDS) se sont montrés moins réactifs à l’ozone, puisque les conversions sont restées assez faibles (de l’ordre de 30% pour un ratio O3/soufrés similaire). Dans la gamme de conditions opératoires utilisées, ni l'humidité, ni le temps de résidence dans le réacteur n’ont montré d'influence considérable. La concentration d'ozone s’avère être le paramètre du procédé le plus influant, ayant un effet positif sur les taux de conversion des trois composés soufrés étudiés. Parallèlement, pour le DMDS, une augmentation de la température du réacteur a aussi amélioré la conversion. De manière globale, les taux de conversion les plus importants ont été obtenus pour les ratio O3/soufrés et la température du réacteur les plus élevés. A l’inverse, même lorsque les conditions de réaction les plus favorables ont été appliquées (température et concentration d’ozone les plus élevées), les aldéhydes se sont montrés non réactifs vis-à-vis de l’ozone. Malgré les faibles conversions obtenues, l’utilisation du SIFT/MS a permis d’identifier les principaux sousproduits de la réaction ozone-composés soufrés en phase gazeuse comme étant le méthyléthylsulfoxyde (MESO), le méthyléthylsulfone (MESO2), le diméthyl thiosulfinate (DMSOS), les isomères de diméthyl thiosulfonate (DMSO2S), le diméthyldisulfoxyde (DM(SO)2) et également le dioxyde (SO2) et le trioxyde de soufre (SO3). Le procédé de traitement des odeurs par ozonation directe des gaz en sortie de cheminée industrielle apparaît donc difficilement envisageable en raison de la faible efficacité d’élimination des composés malodorants démontrée dans nos essais. En revanche, cette technique couplée avec une absorption chimique pourrait s’avérer intéressante pour éliminer les nuisances olfactives avec une bonne efficacité / In the superphosphate-based fertilizers production process, the attack of phosphate rock by sulfuric acid generates odorous gaseous by-products. Although their emissions are within regulatory limits, superphosphate fertilizer plants are likely to cause odor nuisance to residents. This thesis proposes to study the feasibility of a process of odor treatment by ozonation in homogeneous gas phase. A first step of prioritization of the chemical compounds with the most important odorous potential has been realized. This ranking was established from a technical report provided by our industrial partner based on a campaign of olfactometric measurement and chemical characterization of the gases emitted by the chimney of a superphosphate fertilizer production plant. From the calculation of the odor activity value (OAV), two families of compounds were targeted: sulfur compounds - represented by hydrogen sulphide (H2S), ethylmethyl sulphide (MES) and dimethyl disulfide (DMDS) - and aldehydes (represented by propanal and butanal). Two analytical techniques (GC/FID and SIFT/MS) were applied in order to evaluate the elimination performance of these compounds, the difficulty of analyzing a gaseous matrix containing ozone having been demonstrated. Thus, ozone interference on GC/FID analysis of aldehydes has been identified. The SIFT/MS technique, in turn, required significant development. The ozonation of model gaseous effluents was carried out following the elimination of the target compounds under different operating conditions (residence time, reactor temperature, ozone concentration and moisture) in an experimental field compatible with the industrial constraints. The sulfur compounds exhibited high removal rates, particularly in the case of H2S, whose conversions reached about 80%. Organic monosulfides (MES) and disulfides (DMDS) were less reactive to ozone, as conversions remained quite low (around 30% for the same level of O3/sulfur ratio). In the range of operating conditions used, neither the moisture nor the residence time in the reactor showed considerable influence. The ozone concentration is the most influential process parameter, having a positive effect on the conversion rates of the three sulfur compounds studied. Meanwhile, for DMDS, an increase in reactor temperature also improved the conversion. Overall, the highest conversion rates were obtained for the highest O3/sulfur ratios and reactor temperature. Conversely, even when the most favorable reaction conditions have been applied (highest temperature and ozone concentration), the aldehydes have been inert to ozone. Despite the low conversions obtained, the use of SIFT/MS has identified the main by-products of the ozone-sulfur compounds gas phase reaction as methylethylsulfoxide (MESO), methylethylsulfone (MESO2), dimethyl thiosulfinate (DMSOS), isomers of dimethyl thiosulfonate (DMSO2S), dimethyldisulfoxide (DM(SO)2) and also sulfur dioxide (SO2) and trioxide (SO3). The odors treatment process by direct ozonation of the gases at the outlet of industrial chimney thus appears difficult to envisage because of the low efficiency of malodorous compounds elimination demonstrated in our tests. On the other hand, this technique coupled with chemical absorption could be interesting to eliminate the olfactory nuisances with a good efficiency
355

Reactive Blade Coating for Low-Cost Fabrication of Self-Assembled Metal Nanoparticles for Bio-Applications: Disinfecting SARS-CoV-2 to Limit the Spread of COVID-19 Illness

Ebrahimzadeh Asl Tabrizi, Bita 30 April 2021 (has links)
Considerable attention has been focused on nanomaterials and their extensive applications. Metallic nanoparticles, especially gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), due to their superior physical, chemical, and optical properties, are vastly developed for numerous biomedical applications such as drug and gene delivery systems, diagnostic biosensors, imaging, and therapeutics. This study presents a low-cost method for the fabrication of self-assembled metallic nanoparticles, including gold and silver, via a reactive blade coating process, which is carried out based on in situ reduction of the metal precursors. This technique is a roll-to-roll compatible technique suitable for scalable nanomanufacturing. Oleylamine was used as a reducer agent, and gold (III) chloride hydrate and silver salts, including silver nitrate and silver perchlorate hydrate, were used as the metal precursors. Fabrication was carried out by first blade coating the reducer ink and subsequently coating the precursor ink followed by 3 hours of heat treatment. Various solvent systems were used to examine the effect of different solvents on the fabrication process. Surface morphology, crystalline phase composition, and plasmon resonance of the coated samples were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), and UV-Vis spectroscopy, respectively. Results demonstrated the synthesis of spherical self-assembled AuNPs using toluene (TOL) and isopropyl alcohol (IPA) for reducing and precursor solvents, respectively. Changing the concentration of reactants or increasing the coating layers exhibited a change in the average size of AuNPs. Self-assembled AuNPs thin films were also demonstrated to have the potential to be used as a biosensing platform based on localized surface plasmon resonance (LSPR) effect to detect the elevated levels of glucose in an aqueous solution. Recently, the world has faced a pandemic of Covid-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has threatened human health and has brought a worldwide devastating economic and social crisis. Hence, finding a solution to mitigate the current breakout of Covid-19 is vital to protect the international community from its causing harm. AgNPs as an antimicrobial agent, which has exhibited promising antiviral activity against several viruses, can offer a resolution to combat the spread of Covid-19. In this regard, AgNPs thin films were fabricated analogously via blade coating using various reducer and silver salt inks made of different solvent systems. Virucidal efficacy of reactive blade coated AgNPs on glass substrates was analyzed against human coronavirus 229E, a virus from the Coronavirus family, as a surrogate SARS-CoV-2 (according to the Level 2 Biosafety facility at uOttawa). Plaque forming assay indicated more than 99.99% reduction in infectivity of the virus when it contacts the AgNPs coated glass for 30 min before infecting cells. These results suggest the excellent potential for reactive blade coated AgNPs as an antiviral agent against coronavirus to avoid the spread of the virus.
356

Characterization of virus-host interactions using cellular thermal shift assays (CETSA)

Lissner, Robin January 2021 (has links)
No description available.
357

Mesenchymal Stem/Stromal Cells as a Therapeutic Intervention for COVID-19: A Living Systematic Review and Meta-Analysis

Kirkham, Aidan 24 June 2022 (has links)
Background: Since its emergence in December 2019, SARS-CoV-2, the coronavirus responsible for COVID-19, has spread across the globe, infected millions of people and caused several million deaths. One promising intervention to combat the ongoing COVID-19 pandemic is mesenchymal stem/stromal cells (MSCs). Many trials were registered at the onset of the pandemic to determine the safety and efficacy of MSCs in COVID-19 patients. However, currently published studies are underpowered to provide an estimate of safety and efficacy on their own. Thus, a living systematic review (SR) is needed to establish the benefits and drawbacks of MSCs for COVID-19 on a relevant timescale. Methods: Systematic literature searches were conducted on Feb 3rd, 2021 and November 15th, 2021 to identify all English-language, full-text, clinical studies examining MSCs to treat COVID-19. (PROSPERO:CRD42021225431). Findings/Conclusions: Our first search identified nine studies (4 controlled) examining the use of MSC derived products to treat COVID-19 patients. This first iteration of our SR revealed that MSCs were safe and reduced mortality in patients suffering from COVID-19. However, risk of bias (RoB) and poor adherence to ISCT cell product characterization guidelines limited the strength of our conclusions. In the second iteration of our living SR, we only included controlled studies to strengthen our conclusions. We identified eleven controlled studies (5 RCTs). MSCs continued to demonstrate safety and efficacy at reducing mortality at study endpoint (RR: 0.50 [0.34 to 0.75, 95% CI, p=0.0006, I2=0%]). However, we continued to encounter barriers which prevented us from drawing more definitive conclusions. A master protocol appears necessary to facilitate the accelerated accumulation of high-quality evidence where standardized outcome reporting and consistent product characterization allow for a more definitive and timely estimate regarding the safety and efficacy of this cell-based therapy for COVID-19.
358

A RAPID PAPER-BASED COLORIMETRIC MOLECULAR TEST FOR SARS-COV-2 POINT-OF-CARE DIAGNOSTIC

Jiangshan Wang (10725807) 29 April 2021 (has links)
<p>In the year of 2020, an international pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has afflicted tens of millions of people’s life also disrupting global economics. Diagnostic testing is an important part of ensuring public health until a vaccine that has been shown to be safe and effective is made available to the general public. Most tests for detecting COVID-19 utilize quantitative polymerase chain reaction (qPCR) assays, which is a specific and relatively simple quantitative assay that could provide adequate sensitivity for diagnosing early infection. Although powerful, these lab-based molecular assays have a significant lag time, usually several days before receiving results. To satisfy the needs of different purposes (diagnostics, screening, and surveillance), a unified approach is impractical. This thesis presents an alternative testing method supporting the current procedure of point of care (POC) testing and in community testing. This paper-based test overcomes the limitations of current testing methods by utilizing reverse-transcription loop-mediated isothermal amplification (RT-LAMP) and receiving the result on-site by a color change in the presence of the virus within 60 minutes. The test utilizes untreated freshly collected saliva, a less invasive specimen, as the sample and possesses a limit of detection (LoD) of 200 copies of virus per microliter of whole saliva with an analytical sensitivity of 97% and analytical specificity of 100%. The test requires minimal operator training and could be fabricated on a large-scale using roll-to-roll methods. Since the test is based on nucleic acids, the testing platform itself lends to further applications <a>including food safety monitoring, animal diagnostic, etc. simply by changing the specific primers</a>. </p>
359

Clinical characteristics of acute kidney injury in the first 13 critically ill patients infected with SARS-CoV-2 (COVID-19) at a peruvian hospital; a preliminary report

Benites-Flores, Irwing R., Valdivia-Vega, Renzo P., Alcalde-Ruiz, Susan F., Espinoza-Rojas, Hugo J. 01 April 2021 (has links)
Introduction: The high transmissibility and lethality of the novel coronavirus SARS-CoV-2 (COVID-19) have been catastrophic. Acute kidney injury (AKI) is one of the frequent complications in patients with respiratory insufficiency caused by the virus. The pathogenic mechanism is based on the binding of its S-proteins to the angiotensin-converting enzyme (ACE) receptors, which will trigger a cellular damage. A podocyte and tubular compromise are found in the kidneys which can lead to tubular necrosis and the consequent AKI. Objectives: The objective of this report is to identify the main risk factor to develop AKI in patients infected with SARS-CoV-2 with critical acute respiratory distress. Patients and Methods: We performed this report study, collecting data from 48 ICU patients. Data from 13 of them who developed AKI and needed renal replacement therapy (RRT)were analyzed. Clinical characteristics and laboratory findings were reported using STATA 10.0. Results: AKI was present in 27.08% of patients, mostly male (92.3%) with a mean age of 63.8 years old. Hypertension, diabetes and obesity were the main comorbidities in those patients. Additionally, the meantime between admission and AKI diagnosis was 2.69 days. All patients showed fibrinogen, D-dimer, ALT and values above normal range. Mortality was seen in 61.5% of patients. Conclusion: This report tries to show AKI as an important clinical manifestation in critically ill patients infected with SARS-CoV-2, with high mortality. Further studies are needed to demonstrate if there are independent risk factors. / Revisión por pares
360

Impact of Covid-19 Response Strategies on the Rate of Change in Mortality in Europe During the First and Second Waves: A Retrospective Cohort Study

Quattrini, Nicole January 2021 (has links)
The coronavirus disease 2019 (COVID-19) has led to more than 3,000,000 deaths globally. During the first year of the pandemic, countries have focused their response strategies on non-pharmaceutical interventions (NPIs) such as lockdowns and use of facial coverings. Because of collateral effects (psycho-social, and economical) by NPIs, investigating their effectiveness is increasingly important for optimal policies. The aim of this study is to investigate whether varying degrees of response strategies affect the rate of change in mortality at specific time points in the epidemic. The containment and health index (CHI) is used to identify the degree of response measures adopted by each country. Six time points around the peak of daily mortality are identified for the first two epidemiological waves for 40 European countries. The response was then correlated to the rate of change of mortality observed over one week 26 days later (time lag for the intervention to take effect). Spearman’s rank correlation coefficient was used for the unadjusted analysis, and multiple linear regression is used in the adjusted analysis. The intensity of CHI reduced the rate of increase of mortality before the first epidemic peak but had no detectable effect at any other time point. Different covariates and interactions between CHI and covariates such as population density and GDP, affected the rate of change of mortality at different time points during the two waves. NPIs may be effective, as suggested by a significant effect of CHI on mortality early in the first wave. However, the effect is not consistent across time points, and the extent of collateral damage suggests a closer look at other factors influencing the epidemic is necessary.

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