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Multiple relationships between aerosol and COVID-19: a framework for global studies
Get PDFCOVID-19 (Corona Virus Disease 2019) is a severe respiratory syndrome currently causing a human global pandemic. The original virus, along with newer variants, is highly transmissible. Aerosol is a multiphase system consisting of the atmosphere with suspended solid and liquid particles, which can carry toxic and harmful substances; especially the liquid components. The degree to which aerosol can carry the virus and cause COVID-19 disease is of significant research importance. In this study, we have discussed the aerosol transmission as the pathway of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), and the aerosol pollution reduction as a consequence of the COVID-19 lockdown. The aerosol transmission routes of the SARS-CoV-2 can be further subdivided into proximal human-exhaled aerosol transmission and potentially more distal ambient aerosol transmission. The human-exhaled aerosol transmission is a direct dispersion of the SARS-CoV-2. The ambient aerosol transmission is an indirect dispersion of the SARS-CoV-2 in which the aerosol act as a carrier to spread the virus. This indirect dispersion can also stimulate the up-regulation of the expression of SARS-CoV-2 receptor ACE-2 (Angiotensin Converting Enzyme 2) and protease TMPRSS2 (Transmembrane Serine Protease 2), thereby increasing the incidence and mortality of COVID-19. From the aerosol quality data around the world, it can be seen that often atmospheric pollution has significantly decreased due to factors such as the reduction of traffic, industry, cooking and coal-burning emissions during the COVID-19 lockdown. The airborne transmission potential of SARS-CoV-2, the infectivity of the virus in ambient aerosols, and the reduction of aerosol pollution levels due to the lockdowns are crucial research subjects.Cao, YaxinShao, Longyi-will be generated-orcid-0000-0001-9975-6091-600Jones, TimSilva Oliveira, Marcos LeandroGe, ShuoyiFeng, XiaoleiSilva Oliveira, Luis FelipeBéruBé, Kell
A novel framework for capacitated SDN controller placement: balancing latency and reliability with PSO algorithm
No full textSoftware Defined Networking (SDN) is a new network architecture theoretical framework, which based on the partition of the control plane and the data plane. Some of the important features of SDN are centralized network management, open code, scalability, effective utilization of network resources, effective traffic management, security etc. All these administrative decisions taken by the controller which lies at the top of the data plane. Efficient placing of controllers is essential to enhance the network's reliability, which ultimately improves the performance of the network. Much of the work done in the SDN has been aimed on controller placement problems (CPP) by considering latency and reliability of the network separately whereas few of them acknowledged both latency and reliability simultaneously. We considered both communication latency and reliable communication to solve CPP. To achieve this, we aim to minimize the total average latency of the network with a reliable network model that can work perfectly up to the failure of n-1 controllers out of n deployed. We first formulate an efficient algorithm “Capacitated Controllers Arrangement (CCA)” to define the problem and used nature-based metaheuristic technique, Particle Swarm optimization (PSO) to achieve the solution. By intelligently allocating controllers, this dynamic system minimizes network latency and optimizes switch assignments. Three controllers deliver excellent reliability and latency performance even despite controller breakdowns, according to experiments conducted on the Internet2 OS3E architecture. This novel method not only increases SDN efficiency but also establishes a standard for further improvements in controller placement tactics. The outcome shows that the proposed approach achieves its goal efficiently and in future other multi-objective optimization techniques will be explored to solve reliability aware CPP
Signals and linear systems: a novel approach based on infinitesimal calculus (Part I)
Get PDFIn part I of this paper, the development of a course on linear signals and systems is presented, based on an infinitesimal calculus model, called MicroCalculus. Such a calculus model allows a didactic development of the fundamental concepts of a signal course. The signals are defined from the fundamental elements of variable and function. MicroCalculus offers a new vision to signal classification, as well as a treatment of non-standard functions as generalized functions, which in the new calculus model can be treated as standard functions. Then, the development of the discrete and continuous convolution operation is presented, from a unified approach. In part II of this paper, the development of all the transforms that are studied in the Signals and Systems courses is presented, starting from the Discrete Fourier Transform until reaching the Z Transform, passing through the Fourier Series, the Fourier Transform, the Laplace transform, etc. The methodology used consists of constructing the Discrete Fourier Transform in a didactic way, to then deduce all the other entities by using the infinitesimal calculus.Simancas García, JoséGonzález Kemel, GeorgeSimancas García, Jos
Identification of a novel tailor-made chitinase from white shrimp fenneropenaeus merguiensis
Get PDFFenneropenaeus merguiensis (commonly named banana shrimp) is one of the most important farmed crustacean worldwide species for the fisheries and aquaculture industry. Besides its nutritional value, it is a good source of chitinase, an enzyme with excellent biological and catalytic properties for many industrial applications. In the present study, a putative chitinase-encoding cDNA was synthesized from mRNA from F. merguiensis hepatopancreas tissue. Subsequently, the corresponding cDNA was cloned, sequenced and functionally expressed in Escherichia coli, and the recombinant F. merguiensis chitinase (rFmCHI) was purified by His-tag affinity chromatography. The bioinformatics analysis of aminoacid sequence of rFmCHI displayed a cannonical multidomain architecture in chitinases which belongs to glycoside hydrolase family 18 (GH18 chitinase). Biochemical characterization revealed rFmCHI as a monomeric enzyme of molecular weight 52 kDa with maximum activity at 40 °C and pH 6.0 Moreover, the recombinant enzyme is also stable up to 60 °C, and in the pH range 5.0-8.0. Steady-state kinetic studies for colloidal chitin revealed KM, Vmax and kcat values of 78.18 μM, 0.07261 μM. min−1 and 43.37 s−1, respectively. Overall, our results aim to demonstrate the potential of rFmCHI as suitable catalyst for bioconversion of chitin waste.Beygmoradi, AzadehHomaei, Ahmad-will be generated-orcid-0000-0001-9909-4761-600Hemmati, RoohullahDel Arco, Jon-will be generated-orcid-0000-0003-4646-492X-600Fernández-Lucas, Jesús-will be generated-orcid-0000-0001-7045-8306-60
Estimation of cattle weight gain under the influence of meteorological and nutritional variables by applying a multiple linear regression model in Sabanalarga, Colombia
No full textThe present investigation arose from the current problem in the entire territory of the Department of Atlántico in the Republic of Colombia, in which the livestock sector currently lacks a reliable modernization that contributes to the planning and profitability of meat production, translated into weight gain. The main focus of the study gravitated around the ignorance of the real effect exerted by meteorological and nutritional factors on the weight gain of cattle. As a possible solution, it was proposed to carry out a statistical analysis by means of a multiple linear regression model where cattle weight gain was the dependent variable to study under the influence of the following independent variables: accumulated precipitation for two weeks (mm), average daily precipitation for two weeks (mm), average daily forage height consumed for two weeks (cm), percentage daily average of forage consumed during two weeks (%), average protein percentage of forage consumed during two weeks (%), the average maximum temperature recorded during two weeks (°C), the average minimum temperature recorded during two weeks (°C), average daily temperature variation recorded for two weeks (°C) and average relative humidity recorded for two weeks (%). All independent data values were collected in the field. Once the analysis was carried out, it was concluded that there was statistical evidence to affirm that only the independent variables "accumulated precipitation", "average precipitation", "average minimum temperature" and "relative humidity" significantly influenced the changes observed in profit of cattle weight, being formulated a multiple linear regression model that contained only the mentioned variables, the rest were discarded. On the other hand, for the constructed linear regression model, the coefficient of determination R2 = 89.3691% was obtained, that is, for the significance level α = 0.05 (95% confidence level), this determined that the model of Multiple linear regression (A) explained the behavior of the average monthly cattle weight gain by 89.3691%. It was concluded, therefore, that the present work gives veracity to the determination of previous investigations where it is also concluded that the meteorological variables directly affect the changes associated with the weight of cattle for meat production
Emerging technologies in the development of metallic and bimetallic nanoparticles in the last decade: a scientometric analysis
No full textThe development of nanotechnology and nanomaterials has had an upward surge in recent years, not only because of the type of technology but also because of the unique properties and characteristics of nanomaterials. This growth motivated us to make an analysis of emerging technologies in the development of metallic, bimetallic, and metal-oxide nanoparticles covering a period of ten years, which have had a high impact on the development of different products applied to biomedicine, electronics, agriculture, energy, plastics, etc. This research found more than one and a half million scientific papers under the keyword ‘nanotechnology’ in the Scopus database. This article reports a scientometric analysis where aspects such as articles with the highest number of citations, countries with the highest production, representative institutions in the field, authors and the relation of citations, correlations between them, keyword analysis, as well as the most studied topics in this field were investigated. On the other hand, the number of patents produced was reviewed in a general way. The databases Scopus, Journal Citation Report, VOSviewer, and other computer tools were used for the analysis. The results showed the United States (17.3%) and China (15.3%) as the countries with the greatest impact on studying metallic and bimetallic nanoparticles, with a high correlation between different countries. It is worth highlighting the participation of India with 10.1% and more than twice as many scientific papers as Germany; in the case of patents, the United States and China accounted for 55.3% of the total patents
Evaluation of the reactivity of methanol and hydrogen sulfide residues with the Ziegler–Natta catalyst during polypropylene synthesis and Its effects on polymer properties
No full textThe study focused on the evaluation of the influence of inhibitory compounds such as hydrogen sulfide (H2S) and methanol (CH3OH) on the catalytic productivity and properties of the polymers in the polymerization process with the Ziegler–Natta catalyst. The investigation involved experimental measurements, computational calculations using DFT, and analysis of various parameters, such as molecular weight, melt flow index, xylene solubility, and reactivity descriptors. The results revealed a clear correlation between the concentration of H2S and methanol and the parameters evaluated. Increasing the H2S concentrations, on average by 0.5 and 1.0 ppm, resulted in a drastic decrease in the polymer’s molecular weight. A directly proportional relationship was observed between the flow rate and the H2S concentration. In the case of methanol, the change occurred from 60 ppm, causing a sharp decrease in the molecular weight of the polymer, which translates into an increase in the fluidity index and a decrease in solubility in xylene. The presence of these inhibitors also affected the catalytic activity, causing a reduction in the productivity of the Ziegler–Natta catalyst. Computational calculations provided a deeper understanding of the molecular behavior and reactivity of the studied compounds. The computational calculations yielded significantly lower results compared to other studies, with values of −69.0 and −43.9 kcal/mol for the Ti-CH3OH and H2S interactions, respectively. These results indicate remarkable stability in the studied interactions and suggest that both adsorptions are highly favorable
Electrification of industrial processes as an alternative to replace conventional thermal power sources.
No full textThe electrification of industrial processes offers sustainable opportunities for reducing carbon footprints and enhancing energy efficiency in the chemical industry. This paper presents an overview of recent research developments in incorporating electrical energy as a replacement for conventional thermal sources like gas and coal in industrial sectors. A literature review was conducted, identifying 70 relevant articles published until September 2020. The topics cover applications for industrial hydrogen generation processes and others, heat pumps, heat pumps, vapor re-compression systems, electric and magnetic fields as heat sources, nanoparticles for improved heat exchange, and ionized gases (plasma) in heating systems. While the application of industrial electrification shows promise globally, its sustainability depends on the efficiency and cost of electrical energy production and transportation at the regional and national levels. Among the various technologies, heat pumps integrated with vapor re-compression systems (VCR) for chemical processes, particularly in industrial distillation product separation columns, appear to be the most viable and widely applicable for waste heat recovery in the near future. Other technologies like electrochemical, plasma, microwave, magnetic, and electric field heating are still in the early stages of development or are limited to specific pilot or laboratory-scale processes
Clinical characteristics of statin management in a cohort with cardiovascular risk in Colombia
No full textLow-density lipoprotein cholesterol (LDL-C) control is the main goal in atherosclerotic cardiovascular disease (ASCVD). Cardiovascular disease (CVD) risk profiling and LDL-C achievement evidence is necessary in Colombia. We aim to retrospectively characterize a cohort of patients admitted to hospital due to acute coronary syndrome (ACS) in a Colombian institution from Jan-2017 to Aug-2020. 148 adult patients with at least 6-month of follow-up since the ACS event were included. Patients were grouped by risk profile (2020 AACE/ACE guidelines). LDL-C goal achievement and stratification by treatment scheme was explored at baseline and during the follow-up period. No sample size calculation was performed to test the change from baseline in LDL-C after 6 months. The mean age was 66.7 (SD:11.5) years, 93 (62.8%) were men. 16 (10.8%) patients had stable angina, 61 (41.2%) unstable angina, 55 (37.2%) NSTEMI and 16 (10.8%) STEMI. 79 (53.4%) and 69 (46.6%) patients were in the very high-risk (VHR) and extreme risk (ExR) groups, respectively. At hospital admission, 126 (85.1%) patients used statins and 22 (14.9%) were not medicated. 54 (83.1%) and 53 (86.9%) used high-intensity statins (HIS) in the VHR and ExR, respectively, the rest used moderate-intensity statins. 67 (84.8%) in the VHR and 61 (88.4%) in the ExR were not in LDL-C goal. After 6 months, there was no significant LDL-C reduction in the VHR: -14.9% (95% CI -30.4-0.5; p =0.058) and the ExR: -7.8% (95% CI -23.2-7.6; p =0.318). 46 (70.8%) patients in the VHR and 50 (82.0%) in the ExR did not achieve the LDL-C goals. Overall, 7 (4.7%) patients had treatment adjustment (HIS+Ezetimibe/PCSK9i). Limited LDL-C goal achievement was observed. Timely optimization of lipid-lowering treatment is needed to maximize healthcare outcomes and avoid therapeutic inertia. It is strongly recommended to include treatment adherence, education, and lifestyle modifications in the LDL-C goal achievement assessment