Coffee Leaf Rust(Hemileia vastatrix)Disease in Coffee Plants and Perspectives by the Disease Control

Coffee Leaf Rust(CLR)is caused by Hemileia vastatrix in Coffea spp.It is one of the most dangerous phytopathogens for coffee plantations in terms of coffee productivity and coffee cup quality.In this review,we resume the problem of CLR in Mexico and the pathogenesis of H.vastatrix.The review abord plant-pathogen interactions which lead a compatible or incompatible interactions and result in CLR disease or resistance,respectively.The review abord Coffea spp.defense response pathways involved in H.vastatrix pathogenicity.Additionally,current measures to control H.vastatrix proliferation and germination were aborded focused on phytosanitary actions,and biological and chemical control.Finally,new trendlines to reduce the impact of CLR as nanoparticles and nanotechnology were analyzed.

Structural Analysis of TiC and TiC-C Core-Shell Nanostructures Produced by Pulsed-Laser Ablation

This paper reports on the ablation process of a pure Ti solid target immersed in a C-enriched acetone solution, leading to the production of titanium carbide (TiC) and Ti-C core-shell nanostructures. The used route of synthesis is generally called pulsed laser ablation in liquid (PLAL). The presence of carbon structures in the solution contributed to the carbon content in the produced Ti-based nanomaterials. The atomic composition of the produced nanostructures was analyzed using SEM-EDS, while TEM micrographs revealed the formation of spherical TiC and core-shell nanostructures ranging from 40 to 100 nm. The identification of atomic planes by HRTEM confirmed a 10 nm diameter C-shell with a graphite structure surrounding the Ti-core. Raman spectroscopy allowed for the identification of D and G peaks for graphite and a Raman signal at 380 and 600 cm−1, assigned to TiC. The results contribute to the state-of-the-art production of TiC and Ti-C core-shell nanostructures using the PLAL route.

Constrained sintering and wear properties of Cu-WC composite coatings

Coatings of metal matrix composites(Cu?WC)were fabricated by solid-state sintering.WC reinforcing particles indifferent quantities from5%up to30%(volume fraction)were mixed with Cu particles.After mixing,the powders were poured ontothe surface of copper substrates.Sintering was carried out at1000°C under a reducing atmosphere in a vertical dilatometer.Sinteringkinetics was affected by both rigid substrates and WC particles which retarded the radial and axial densification of powders.However,the coatings were strongly attached to the substrate,and WC particles were randomly distributed within the matrix.The addition ofthe reinforcing particles enhanced the microhardness and reduced the volume loss in wear tests to1/17compared to the unreinforcedsample.The predominant wear mechanism was identified as abrasion at a load of5N.20%WC(volume fraction)reinforcingparticles led to the maximum values of properties for the composite coating.

Artificial intelligence model validation before its application in clinical diagnosis assistance

The process of selecting an artificial intelligence(AI)model to assist clinical diagnosis of a particular pathology and its validation tests is relevant since the values of accuracy,sensitivity and specificity may not reflect the behavior of the method in a real environment.Here,we provide helpful considerations to increase the success of using an AI model in clinical practice.

Different kinds of stem cells in the development of SARS-CoV-2 treatments

On February 11,2020,the World Health Organization officially announced the coronavirus disease 2019(COVID-19)caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),as an emerging recent pandemic illness,which currently has approximately taken the life of two million persons in more than 200 countries.Medical,clinical,and scientific efforts have focused on searching for new prevention and treatment strategies.Regenerative medicine and tissue engineering focused on using stem cells(SCs)have become a promising tool,and the regenerative and immunoregulatory capabilities of mesenchymal SCs(MSCs)and their exosomes have been demonstrated.Moreover,it has been essential to establishing models to reproduce the viral life cycle and mimic the pathology of COVID-19 to understand the virus's behavior.The fields of pluripotent SCs(PSCs),induced PSCs(iPSCs),and artificial iPSCs have been used for this purpose in the development of infection models or organoids.Nevertheless,some inconveniences have been declared in SC use;for example,it has been reported that SARS-CoV-2 enters human cells through the angiotensin-converting enzyme 2 receptor,which is highly expressed in MSCs,so it is important to continue investigating the employment of SCs in COVID-19,taking into consideration their advantages and disadvantages.In this review,we expose the use of different kinds of SCs and their derivatives for studying the SARS-CoV-2 behavior and develop treatments to counter COVID-19.

A Numerical Study Comparing the Effect on Residual Stresses of Two Different Types of Projectiles During Shot Peening

Shot peening is a widely used technique to improve fatigue life in metallic alloys.This processing technique introduces a subsurface compressive residual stress field through a plastic deformation of the surface caused by the impact of a large number of high-speed projectiles.There are a number of parameters that affect the residual stress field depth and magnitude.The effects of the impact angle,shot speed and shot geometry are currently being researched.In particular,substituting spherical cast shots by cylindrical cut wire shots is an attractive option,especially in terms of cost.The effect of shot geometry on residual stresses,however,needs to be further investigated.Because industrial-scale experimentation is costly and cumbersome,mathematical modeling offers a convenient alternative to carry out this type of research.The present work shows a comparison between the residual stresses generated by the impact of spherical and cylindrical projectiles on a steel substrate.This threedimensional model was developed using ABAQUS finite element commercial software(Release 6.12,Dassault Systémes,France).The results show that cylindrical shots generate residual stress fields t hat a re higher in magnitude than t hose generated by a spherical shot.However,the residual stress field of cylindrical shots impacting the surface at an oblique angle shows an important degree of asymmetry.This effect is not found when spherical shots impact the surface at the same oblique angle.

Fuzzy Rules to Improve Traffic Light Decisions in Urban Roads

Many researchers around the world are looking for developing techniques or technologies that cover traditional and recent constraints in urban traffic con-trol. Normally, such traffic devices are facing with a large scale of input data when they must to response in a reliable, suitable and fast way. Because of such statement, the paper is devoted to introduce a proposal for enhancing the traffic light decisions. The principal goal is that a semaphore can provide a correct and fluent vehicular mobility. However, the traditional semaphore operative ways are outdated. We present in a previous contribution the development of a methodology capable of improving the vehicular mobility by proposing a new green light interval based on road conditions with a CBR approach. However, this proposal should include whether it is needed to modify such light duration. To do this, the paper proposes the adaptation of a fuzzy inference system helping to decide when the semaphore should try to fix the green light interval according to specific road requirements. Some experiments are conducted in a simulated environment to evaluate the pertinence of implementing a decision-making before the CBR methodology. For example, using a fuzzy inference approach the decisions of the system improve almost 18% in a set of 10,000 experiments. Finally, some conclusions are drawn to emphasize the benefits of including this technique in a methodology to implement intelligent semaphores.

Increasing Efficiency of an Intelligent Semaphore by Implementing an ID3 Approach in Decision-Making

The main objective of a semaphore is to provide a correct and fluent vehicular mobility. Many countries around the world are using such devices in urban areas. However, the traditional semaphore operative ways are outdated. We report in a previous contribution the development of a methodology capable of improving the vehicular mobility by proposing a new green light interval based on road conditions with a CBR approach. However, this proposal should include whether it is needed to modify such light duration. To do this, the paper proposes the adaptation of an inductive decision tree helping to decide when the semaphore should try to fix the green light interval according to specific road requirements. Some experiments are conducted in a simulated environment to evaluate the pertinence of implementing a decision-making before the CBR methodology. For example, using the ID3 approach the decisions of the system improve almost 8% in a set of 10,000 experiments. Finally, some conclusions are drawn to emphasize the benefits of including this technique in a methodology to implement intelligent semaphores.

Sintering kinetics of Ni_2FeSb powder alloys produced by mechanical milling

A ternary Ni2FeSb shape memory alloy was fabricated by powder metallurgy route. Sintering kinetics was estimated from dilatometry tests; whereas the microstructure and morphology of the powder and consolidated bulk samples were evaluated by XRD and SEM, respectively. Microhardness tests were performed on the surface of sintered samples. The results indicated that milling time has an effect on the shape and particle size as well as the homogeneity of the crystalline structures of the powders. Samples with longer milling time presented higher relative densities, better distribution of the elements on the alloy as well as the L21 and martensite phases, which will give the shape memory effect. The estimated activation energy values ranged from 109 to 282 kJ/mol at temperatures between 750 and 1273 K, indicating that sintering is controlled mainly by volume diffusion. Microhardness was improved by increasing the milling time and the heating rate.

Interaction of piRNA-like sequences from the 3′-UTR of SARS-CoV-2 with mRNA regions

Piwi-interacting RNAs(piRNAs of 26-32 nt in length)regulate gene expression,epigenetics,and transcriptional and post-transcriptional processes.1 In humans,piRNAs are expressed in germline and somatic tissues,and generally have a uracil at the 5'-end(position+1),an adenine at the+10 position,and are 2'-0 methylated at the 3'-end.2 Onice piRNAs form the RNA-induced silencing complex(RISC)with PIWl proteins,they serve as guides to find their complementary sequences of the target mRNA,thus initiating their degradation.The Wuhan patient's genome is approximately 265 nucleotides(nts)in its 3'-UTR;piRNAs-like sequences have been reported in this region.3 Our objective was to search,through bioinformatics,for mRNA sequences that were homologous to the reverse complementary of the previously reported piRNA-like sequences from the 3'-UTR of SARS-Cov-2,3 and identify the possible interaction between them.

Analysis and Validation for an Inverter-side Current Controller in LCL Grid-connected Power Systems

Transformerless grid-connected inverters offer greater efficiencies when transferring power from renewable energy sources to the electrical grid.If the grid-inverter connection is done with an LCL filter,high attenuation of switching harmonics is achieved while preserving a small-size output filter.However,damping must be included in the controller to assure closed-loop stability.This paper proposes a reference computation methodology for the inverter-side current feedback in a photovoltaic(PV)generation system connected to the grid through an LCL filter.Theoretical analysis of the closed-loop system stability and of the steady-state performance are presented as well as experimental validation of the closed-loop performance.The feedback controller includes active damping and relies on a resonant control structure which improves the ability of dealing with grid harmonic distortion.The controller uses a reduced set of measurements,which requires the inverter-side current and grid voltage only,and assures a power factor close to unity.

Influence of the starter culture on the volatile profile of processed cocoa beans by gas chromatography–mass spectrometry in high resolution mode

Cocoa is the main component of chocolate.It is widely accepted that cocoa quality largely depends on the processing,especially the fermentation step.Traditionally,fermentation takes place spontaneously by the endogenous microbiota;however,the process can lead to poor quality and heterogeneity of the final product.In this study,we evaluated the influence of the starter culture on the profile of volatiles during fermentation of commercial volumes of Mexican cocoa.Volatiles were also analyzed in post-fermented cocoa samples obtained after drying,roasting,and conching.Our results revealed a most desirable volatile profile in cocoa fermented with starter culture,mainly due to the higher relative content of alcohols(40%)and aldehydes(3.5%),but also due to a lower acidity(<1%)as compared to endogenous fermentation(acids,65%;alcohols,2%;and aldehydes<0.5%).Additionally,it is remarkable,the higher content of pyrazines in the inoculated samples after processing.