68 research outputs found
FTN â Frequent Transit Network: Transit Strategies towards Achieving Transit-Oriented Development in Alexandria City, Egypt
Land use policy and transport policy are normally integrated through transit-oriented development (TOD) strategies. (TOD) is a "mixed-use communityâ, that encourages people to live near transit services and to decrease dependence on their driving. Instead of requiring riders to consult a timetable or wait for extended periods of time, transit service is most appealing when it is frequent enough that riders can arrive at a stop knowing that a bus or train will arrive soon. Frequent Transit Networks (FTNs) aim to deliver services in high-demand areas in a convenient, connected, and memorable. (FTNs) are intended to serve the locations that the majority of people want to visit most frequently and to make service convenient by operating at least every 15 minutes from early morning until at least mid-afternoon. This paper discusses, evaluates, and looks into the possibility of implementing TOD and FTNs in Alexandria, Egypt. Alexandria is experiencing a sharp increase in transport demand as a result of its rapid urbanisation. With the narrow streets and limited spaces the rapid urbanisation process has led to a significant increase in traffic volume. This paper adopts the Frequent Transit Network (FTNs) strategies in identifying corridors linking the cityâs urban centers and the nodes where these corridors intersect. The main purpose is to direct growth , development and to create a proposal for a âSystem Backboneâ that provides a structure for other services. Expected findings from this study is to perform a framework that identify potential (FTN) solutions for the city. It also proposes a âKey Corridor Networkâ for the bus routes and light rail transit, emphasising corridors in which combined transport services could provide a more efficient operation of the cityâs public transport
Effect of Synthesized Titanium Dioxide Nanofibers Weight Fraction on the Tribological Characteristics of Magnesium Nanocomposites Used in Biomedical Applications
Biomedical applications, such as artificial implants, are very significant for the disabled due to their usage in orthopedics. Nevertheless, available materials in such applications have insufficient mechanical and tribological properties. The current study investigated the mechanical and tribological properties of a biomedical metallic material, magnesium (Mg), after incorporating titanium dioxide nanofibers (TiO2) with different loading fractions. The TiO2 nanofibers were synthesized using the electrospinning technique. The ball-milling technique was utilized to ensure the homogenous distribution of TiO2 nanofibers inside the Mg matrix. Then, samples of the mixed powder with different loading fractions of TiO2 nanofibers, 0, 1, 3, 5, and 10 wt.%, were fabricated using a high-frequency induction heat sintering technique. The physicomechanical and tribological properties of the produced Mg/TiO2 nanocomposites were evaluated experimentally. Results showed an enhancement in mechanical properties and wear resistance accompanied by an increase in the weight fraction of TiO2 nanofibers up to 5%. A finite element model was built to assess the load-carrying capacity of the Mg/TiO2 composite to estimate different contact stresses during the frictional process. The finite element results showed an agreement with the experimental results
Heteroaromatization with 4-phenyldiazenyl-1-naphthol. Part II: Synthesis of some new benzochromens, benzochromenopyrimidines, benzochromenotriazolopyrimidines, benzochromenopyrimidotriazepine and antimicrobial activities
Synthesis of several new of benzochromenes (4-7), benzochromenopyrimidines (8 and 9), 14-(4-chlorophenyl)-12-(phenyldiazenyl)-14H-benzo[7,8]chromeno[3,2-e][1, 2, 4]triazolo[1, 5-c]pyrimidines, 4-amino-16-(4-chlorophenyl)-14-(phenyldiazenyl)-16H-benzo[7', 8']chro-meno[2',3':4,5]pyrimido[1,6-b][1,2,4]triazepine-3-carbonitrile (10a-e, 13) and 9-(benz-ylideneamino)-7-(4-chlorophenyl)-5-(phenyldiazenyl)-7, 9-dihydro-8H-benzo[7,8]chromeno [2,3-d]pyrimidin-8-imine (12), form starting from 2-amino-4-(p-chlorophenyl)-6-phenyl-diazenyl-4H-benzochromene-3-carbonitrile (3). The structure of these new compounds was confirmed using IR, 1H NMR and 13C NMR as well as MS spectroscopy. The structure activity relationship studies of the target compounds in agreement with the in vitro essays and confirmed higher potent antimicrobial activity against some of the tested microorganisms. The structure-activity relationship study revealed that the antimicrobial activity of benzochromenopyrimido triazepine nucleus was more beneficial than benzochromeno-triazolopyrimidine nucleus for antimicrobial activity
Effect of Nickel Content on the Corrosion Resistance of Iron-Nickel Alloys in Concentrated Hydrochloric Acid Pickling Solutions
The effect of Ni content on the resistance against corrosion of Fe-36% Ni and Fe-45% Ni alloys in 1âM hydrochloric acid pickling solution was reported. Various electrochemical and spectroscopic techniques such as potentiodynamic cyclic polarization (CPP), open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiostatic current-time (PCT), and scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) have been employed. CPP measurements indicated that the corrosion current and corrosion rate recorded lower values for the alloy that had higher nickel content. OCP curves proved that the presence of high Ni content shifts the absolute potential to the positive potential direction. EIS results revealed that the surface and polarization resistances were much higher for the alloy with higher Ni content. PCT curves also showed that the absolute currents were lower for Fe-45% Ni alloy. All results were in good agreement with others and confirmed clearly that the corrosion resistance in HCl solutions for Fe-45% Ni alloy was higher than that obtained for Fe-45% Ni alloy
Stability analysis of the magnetized casson nanofluid propagating through an exponentially shrinking/stretching plate: Dual solutions
In this research, we intend to develop a dynamical system for the magnetohydrodynamic (MHD) flow of an electrically conducting Casson nanofluid on exponentially shrinking and stretching surfaces, in the presence of a velocity and concertation slip effect, with convective boundary conditions. There are three main objectives of this article, specifically, to discuss the heat characteristics of flow, to find multiple solutions on both surfaces, and to do stability analyses. The main equations of flow are governed by the Brownian motion, the Prandtl number, and the thermophoresis parameters, the Schmid and Biot numbers. The shooting method and three-stage Lobatto IIIa formula have been employed to solve the equations. The ranges of the dual solutions are fwc1â€fw and λcâ€Î» , while the no solution ranges are fwc1>fw and λc>λ . The results reveal that the temperature of the fluid increases with the extended values of the thermophoresis parameter, the Brownian motion parameter, and the Hartmann and Biot numbers, for both solutions. The presence of dual solutions depends on the suction parameter. In order to indicate that the first solution is physically relevant and stable, a stability analysis has been performed
Investigation of the Mechanical and Tribological Behavior of Epoxy-Based Hybrid Composite
The main target of this study is to evaluate the impact of hybrid reinforcement using Al2O3 nanoparticles and graphite on the epoxy nanocompositesâ mechanical and tribological properties. Various weight fractions of the reinforcement materials, ranging from 0 to 0.5 wt.%, were incorporated into the epoxy. The aim is to enhance the characteristics and durability of the polymers for potential utilization in different mechanical applications. The addition of hybrid additives consisting of Al2O3 nanoparticles and graphite to the epoxy resin had a noticeable effect on the performance of the epoxy nanocomposites. The incorporation of these additives resulted in increased elasticity, strength, toughness, ductility, and hardness as the concentration of reinforcement increased. The enhancement in the stiffness, mechanical strength, toughness and ductility reached 33.9%, 25.97%, 25.3% and 16.7%, respectively. Furthermore, the frictional tests demonstrated a notable decrease in both the coefficient of friction and wear with the rise of the additivesâ weight fraction. This improvement in the structural integrity of the epoxy nanocomposites led to enhanced mechanical properties and wear resistance. The SEM was utilized to assess the surfaces of tested samples and provide insights into the wear mechanism
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
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
Fungal biodiversity in a new winery and population dynamics in the winery (Saccharomyces cerevisiae) and in aging cellar (Brettanomyces bruxellensis)
La biodiversitĂ© fongique interspĂ©cifique (Illumina Mi-Seq) et la dynamique des espĂšces Saccharomyces cerevisiae et Brettanomyces bruxellensis ont Ă©tĂ© Ă©tudiĂ©es au sein dâune nouvelle cuverie et/ou dans 3 caves dâĂ©levage, plus particuliĂšrement sur le sol, les murs, le matĂ©riel vinaire et lâextĂ©rieur des fĂ»ts. Dans la nouvelle cuverie, un consortium fongique (levures et moisissures) de dĂ©part est dĂ©jĂ prĂ©sent sur tous les environnments Ă©tudiĂ©s avant lâarrivĂ©e de la premiĂšre vendange. Ce consortium est constituĂ© de genres tels que Aureobasidium, Alternaria, Didymella et Filobasidium. Ces genres qui persistent pendant deux millĂ©simes, ne sont pas spĂ©cifiques de lâenvironnement de la cuverie et semblent ĂȘtre adaptĂ©s Ă tous les environnements naturels ou anthropiques au regard de leur caractĂšre ubiquiste. Le consortium de dĂ©part est enrichi par des genres Ćnologiques (exemple : Hanseniaspora, Saccharomyces) qui sont introduits dans la cuverie soit par les vendanges, soit par des transferts potentiels entre les diffĂ©rents environnements de la cuverie. Cependant, ces genres ne semblent pas persister ou sâimplanter probablement dĂ» Ă leur faible adaptation aux conditions stressantes de lâenvironnement de la cuverie. La dynamique de la flore indigĂšne S. cerevisiae dans la nouvelle cuverie a Ă©tĂ© Ă©galement Ă©tudiĂ©e. Aucun isolat appartenant Ă cette espĂšce nâa Ă©tĂ© retrouvĂ© avant l'arrivĂ©e de la premiĂšre vendange confirmant que cette espĂšce nâest pas spĂ©cifique de l'environnement de la cuverie et que sa prĂ©sence est en lien avec l'activitĂ© des fermentations alcooliques. Cependant, les rĂ©sultats obtenus suggĂšrent une colonisation potentielle de lâenvironnement de la nouvelle cuverie par certaines souches de S. cerevisiae. Ces souches dites « colonisatrices » ont prĂ©sentĂ© une capacitĂ© plus Ă©levĂ©e Ă former des biofilms comparĂ©e Ă celle de souches non implantĂ©es. Cette Ă©tude met en Ă©vidence lâimportance de lâenvironnement de la cuverie qui constitue une vĂ©ritable niche Ă©cologique pour les populations fongiques capables de sâimplanter au cours du processus de vinification. Dans lâenvironnement des 3 caves dâĂ©levage, le matĂ©riel vinaire et lâextĂ©rieur des fĂ»ts (en contact direct avec le vin) sont les environnements qui semblent favorables au dĂ©veloppement et Ă lâinstallation des populations microbiennes cultivables (levures totales et bactĂ©ries lactiques) et des microorganismes dâaltĂ©ration (bactĂ©ries acĂ©tiques et B. bruxellensis), contrairement au sol et aux murs oĂč des populations faibles ont Ă©tĂ© trouvĂ©es. Des souches rĂ©currentes de B. bruxellensis ont Ă©tĂ© retrouvĂ©es sur le matĂ©riel et sur lâextĂ©rieur des fĂ»ts et pourraient ĂȘtre Ă lâorigine de la contamination de vins au cours de lâĂ©levage. Ces souches rĂ©currentes prĂ©sentent des capacitĂ©s de formation de biofilms et de rĂ©sistance plus importantes qui pourraient expliquer la persistance de B. bruxellensis dans des caves dâĂ©levage. Ces rĂ©sultats soulignent lâimportance du nettoyage du matĂ©riel vinaire et du suivi microbien rĂ©gulier des vins au cours de lâĂ©levage afin de limiter les contaminations.The interspecific fungal biodiversity (Illumina Mi-Seq) and the dynamics of Saccharomyces cerevisiae and Brettanomyces bruxellensis species were studied in a new winery and/or in 3 aging cellars, more specifically on the floor, the walls, the equipment and the outside of the barrels. In the new winery, an initial fungal consortium (yeasts and molds) is already present on all the winery environments before the arrival of the first harvest. This consortium consists of fungal genera such as Aureobasidium, Alternaria, Didymella and Filobasidium. These genera, that persist during two vintages, are not specific to the winery environment and seem to be adapted to natural or anthropic environments due to their ubiquitous character. The initial consortium is enriched by oenological genera (e.g. Hanseniaspora, Saccharomyces) that are introduced into the winery either by the harvest or by potential transfers between the different environments of the winery. However, these genera do not seem to persist or establish due to their low adaptation to the stressful conditions of the winery environment. The dynamics of wild S. cerevisiae in the new winery was also studied. No isolates belonging to this species were found before the arrival of the first harvest, confirming that this species is not specific to the winery environment and its presence is related to the alcoholic fermentation activity. However, the results obtained suggest a potential colonization of the new winery environment by certain S. cerevisiae strains. These so-called « colonizing » strains showed a higher capacity to form biofilms compared to non-implanted strains. This study highlights the importance of the winery environment that constitutes a true ecological niche for fungal populations capable of implantation during the winemaking process. In the environment of the 3 aging cellars, the equipment and the outside of the barrels (in direct contact with wine) are the environments that seem to be favorable for the development and installation of cultivable microbial populations (yeasts and lactic acid bacteria) and spoilage microorganisms (acetic acid bacteria and B. bruxellensis), unlike the floor and the walls where low microbial populations were found. Recurrent strains of B. bruxellensis have been found on both the equipment and the outside of the barrels and could be the cause of wine contamination during aging. These recurrent strains showed greater biofilm formation and resistance capacities which could explain the persistence of B. bruxellensis in aging cellars. These results highlight the importance of equipment cleaning and the regular monitoring of wines during aging in order to limit the contaminations
Biodiversité fongique dans une nouvelle cuverie et dynamique des populations en cuverie (Saccharomyces cerevisiae) et en cave d'élevage (Brettanomyces bruxellensis)
The interspecific fungal biodiversity (Illumina Mi-Seq) and the dynamics of Saccharomyces cerevisiae and Brettanomyces bruxellensis species were studied in a new winery and/or in 3 aging cellars, more specifically on the floor, the walls, the equipment and the outside of the barrels. In the new winery, an initial fungal consortium (yeasts and molds) is already present on all the winery environments before the arrival of the first harvest. This consortium consists of fungal genera such as Aureobasidium, Alternaria, Didymella and Filobasidium. These genera, that persist during two vintages, are not specific to the winery environment and seem to be adapted to natural or anthropic environments due to their ubiquitous character. The initial consortium is enriched by oenological genera (e.g. Hanseniaspora, Saccharomyces) that are introduced into the winery either by the harvest or by potential transfers between the different environments of the winery. However, these genera do not seem to persist or establish due to their low adaptation to the stressful conditions of the winery environment. The dynamics of wild S. cerevisiae in the new winery was also studied. No isolates belonging to this species were found before the arrival of the first harvest, confirming that this species is not specific to the winery environment and its presence is related to the alcoholic fermentation activity. However, the results obtained suggest a potential colonization of the new winery environment by certain S. cerevisiae strains. These so-called « colonizing » strains showed a higher capacity to form biofilms compared to non-implanted strains. This study highlights the importance of the winery environment that constitutes a true ecological niche for fungal populations capable of implantation during the winemaking process. In the environment of the 3 aging cellars, the equipment and the outside of the barrels (in direct contact with wine) are the environments that seem to be favorable for the development and installation of cultivable microbial populations (yeasts and lactic acid bacteria) and spoilage microorganisms (acetic acid bacteria and B. bruxellensis), unlike the floor and the walls where low microbial populations were found. Recurrent strains of B. bruxellensis have been found on both the equipment and the outside of the barrels and could be the cause of wine contamination during aging. These recurrent strains showed greater biofilm formation and resistance capacities which could explain the persistence of B. bruxellensis in aging cellars. These results highlight the importance of equipment cleaning and the regular monitoring of wines during aging in order to limit the contaminations.La biodiversitĂ© fongique interspĂ©cifique (Illumina Mi-Seq) et la dynamique des espĂšces Saccharomyces cerevisiae et Brettanomyces bruxellensis ont Ă©tĂ© Ă©tudiĂ©es au sein dâune nouvelle cuverie et/ou dans 3 caves dâĂ©levage, plus particuliĂšrement sur le sol, les murs, le matĂ©riel vinaire et lâextĂ©rieur des fĂ»ts. Dans la nouvelle cuverie, un consortium fongique (levures et moisissures) de dĂ©part est dĂ©jĂ prĂ©sent sur tous les environnments Ă©tudiĂ©s avant lâarrivĂ©e de la premiĂšre vendange. Ce consortium est constituĂ© de genres tels que Aureobasidium, Alternaria, Didymella et Filobasidium. Ces genres qui persistent pendant deux millĂ©simes, ne sont pas spĂ©cifiques de lâenvironnement de la cuverie et semblent ĂȘtre adaptĂ©s Ă tous les environnements naturels ou anthropiques au regard de leur caractĂšre ubiquiste. Le consortium de dĂ©part est enrichi par des genres Ćnologiques (exemple : Hanseniaspora, Saccharomyces) qui sont introduits dans la cuverie soit par les vendanges, soit par des transferts potentiels entre les diffĂ©rents environnements de la cuverie. Cependant, ces genres ne semblent pas persister ou sâimplanter probablement dĂ» Ă leur faible adaptation aux conditions stressantes de lâenvironnement de la cuverie. La dynamique de la flore indigĂšne S. cerevisiae dans la nouvelle cuverie a Ă©tĂ© Ă©galement Ă©tudiĂ©e. Aucun isolat appartenant Ă cette espĂšce nâa Ă©tĂ© retrouvĂ© avant l'arrivĂ©e de la premiĂšre vendange confirmant que cette espĂšce nâest pas spĂ©cifique de l'environnement de la cuverie et que sa prĂ©sence est en lien avec l'activitĂ© des fermentations alcooliques. Cependant, les rĂ©sultats obtenus suggĂšrent une colonisation potentielle de lâenvironnement de la nouvelle cuverie par certaines souches de S. cerevisiae. Ces souches dites « colonisatrices » ont prĂ©sentĂ© une capacitĂ© plus Ă©levĂ©e Ă former des biofilms comparĂ©e Ă celle de souches non implantĂ©es. Cette Ă©tude met en Ă©vidence lâimportance de lâenvironnement de la cuverie qui constitue une vĂ©ritable niche Ă©cologique pour les populations fongiques capables de sâimplanter au cours du processus de vinification. Dans lâenvironnement des 3 caves dâĂ©levage, le matĂ©riel vinaire et lâextĂ©rieur des fĂ»ts (en contact direct avec le vin) sont les environnements qui semblent favorables au dĂ©veloppement et Ă lâinstallation des populations microbiennes cultivables (levures totales et bactĂ©ries lactiques) et des microorganismes dâaltĂ©ration (bactĂ©ries acĂ©tiques et B. bruxellensis), contrairement au sol et aux murs oĂč des populations faibles ont Ă©tĂ© trouvĂ©es. Des souches rĂ©currentes de B. bruxellensis ont Ă©tĂ© retrouvĂ©es sur le matĂ©riel et sur lâextĂ©rieur des fĂ»ts et pourraient ĂȘtre Ă lâorigine de la contamination de vins au cours de lâĂ©levage. Ces souches rĂ©currentes prĂ©sentent des capacitĂ©s de formation de biofilms et de rĂ©sistance plus importantes qui pourraient expliquer la persistance de B. bruxellensis dans des caves dâĂ©levage. Ces rĂ©sultats soulignent lâimportance du nettoyage du matĂ©riel vinaire et du suivi microbien rĂ©gulier des vins au cours de lâĂ©levage afin de limiter les contaminations
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