Atomistic modelling of anisotropic etching of crystalline silicon

An atomistic model for the simulation of anisotropic wet chemical etching of crystalline silicon is developed. Special attention is paid to the relation between the atomistic processes, the mesoscopic features of the surface morphology and the macroscopic anisotropy of the process, bridging the different length scales. The development of the atomistic model is made by direct comparison of atomistic kinetic Monte Carlo and Cellular Automaton simulations with experimental results, guided by first-principles calculations. The model explains the anisotropy of the etching process and the orientation-dependent surface morphology as two different manifestations of the same atomistic mechanisms, namely, the weakening of backbonds following OH termination of surface atoms and the existence of significant interaction between the terminating species (H / OH). The versatility of the atomistic model is demonstrated by the concentration and time dependence of the simulated under-etched structures and surface morphology. A substantial effort has been made to develop an efficient program in order to simulate the etching process in arbitrarily oriented, large, micrometer-scale systems in the presence (or absence) of masking patterns and considering the effects of temperature and etchant concentration. The program has a great potential for use in the optimization of the processing parameters in industrial applications.reviewe

Effect of Cu impurities on wet etching of Si(110): formation of trapezoidal hillocks

We simulate the formation of experimentally observed trapezoidal hillocks on etched Si(110) surfaces, describing their generic geometrical shape and analyzing the relative stability and/or reactivity of the key surface sites. In our model, the hillocks are stabilized by Cu impurities in the etchant adsorbing on the surface and acting as pinning agents. A model of random adsorptions will not result in hillock formation since a single impurity is easily removed from the surface. Instead a whole cluster of Cu atoms is needed as a mask to stabilize a hillock. Therefore we propose and analyze mechanisms that drive correlated adsorptions and lead to stable Cu clusters.Peer reviewe

Effect of Sperm Concentration and Storage Temperature on Goat Spermatozoa during Liquid Storage

One of the problems with the refrigerated storage of spermatozoa in goats is the short shelf life. The study of the effect of the different storage conditions on the di erent sperm parameters could help to increase sperm survival. In this work, we studied the effect of temperature and sperm concentration during refrigerated storage on sperm motility, mitochondrial membrane potential and DNA fragmentation. We observed that refrigerated storage of semen doses reduced the majority of sperm quality parameters, however, sperm DNA fragmentation was not a ected. Storage at 5ºC preserved higher sperm motility than at 17ºC. Moreover, the reduction of sperm concentration below 500x10(6) sperm/mL did not seem to improve the quality of spermatozoa

Polinucleótidos y su uso para obtener plantas resistentes a virus

La presente invención se refiere a secuencias nucleotídicas de elF4E utilizadas para la formación de un ARN de interferencia y su uso para silenciar específicamente el factor de iniciación de la traducción elF4E pero no a su isoforma, el factor elF(iso)4E, obteniendo de esta manera plantas resistentes a al menos un tipo de virus o que mejoran su resistencia al mismo, respecto de un control.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Imaging Techniques to Study Plant Virus Replication and Vertical Transmission

This article belongs to the Special Issue Application of Advanced Imaging to the Study of Virus-Host Interactions.Plant viruses are obligate parasites that need to usurp plant cell metabolism in order to infect their hosts. Imaging techniques have been used for quite a long time to study plant virus–host interactions, making it possible to have major advances in the knowledge of plant virus infection cycles. The imaging techniques used to study plant–virus interactions have included light microscopy, confocal laser scanning microscopy, and scanning and transmission electron microscopies. Here, we review the use of these techniques in plant virology, illustrating recent advances in the area with examples from plant virus replication and virus plant-to-plant vertical transmission processes.Research on PepMV in our laboratory is currently funded by grant RTI2018-097099-B-100 (Ministerio de Ciencia e Innovación, Spain).Peer reviewe

Pol ynucleotides and use thereof for obtaining plants resistant to multiple viruses including cucumber vein yellowing virus (cvyv), moroccan watermelon mosaic virus (mwmv), melon necrotic spot virus (mnsv) and zucchini yellow mosaic virus (zymv)

[EN] The invention relates to nucleotide sequences of e1F4E used to fonn an interfering RNA and to the use thereoffor specifically silencing translation initiation factor eIF4E, but not the isofonn thereof, factor eIF(iso)4E, thereby obtaining plants which are resistant to different types ofviruses or with improved resistance to same in relation to a control.[ES] La presente invención se refiere a secuencias nucleotídicas de eIF4E utilizadas para la fonnación de un ARN de interferencia y su uso para silenciar específicamente el factorde iniciación de la traducción eIF4Epero no a su isofonna, el factor eIF(iso)4E, obteniendo de esta manera plantas resistentes a variostiposde virus o que mejoran su resistencia alosmismos, respecto de un control.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Editing melon eIF4E associates with virus resistance and male sterility

The cap-binding protein eIF4E, through its interaction with eIF4G, constitutes the core of the eIF4F complex, which plays a key role in the circularization of mRNAs and their subsequent cap-dependent translation. In addition to its fundamental role in mRNA translation initiation, other functions have been described or suggested for eIF4E, including acting as a proviral factor and participating in sexual development. We used CRISPR/Cas9 genome editing to generate melon eif4e knockout mutant lines. Editing worked efficiently in melon, as we obtained transformed plants with a single-nucleotide deletion in homozygosis in the first eIF4E exon already in a T0 generation. Edited and non-transgenic plants of a segregating F2 generation were inoculated with Moroccan watermelon mosaic virus (MWMV); homozygous mutant plants showed virus resistance, while heterozygous and non-mutant plants were infected, in agreement with our previous results with plants silenced in eIF4E. Interestingly, all homozygous edited plants of the T0 and F2 generations showed a male sterility phenotype, while crossing with wild-type plants restored fertility, displaying a perfect correlation between the segregation of the male sterility phenotype and the segregation of the eif4e mutation. Morphological comparative analysis of melon male flowers along consecutive developmental stages showed postmeiotic abnormal development for both microsporocytes and tapetum, with clear differences in the timing of tapetum degradation in the mutant versus wild-type. An RNA-Seq analysis identified critical genes in pollen development that were down-regulated in flowers of eif4e/eif4e plants, and suggested that eIF4E-specific mRNA translation initiation is a limiting factor for male gametes formation in melonThis work was supported by grants AGL2015-65838 and PLEC2021-007715 from Ministerio de Ciencia e Innovacion (Spain) and 2I16SA000057 of the RIS3Mur program from Consejería de empleo, universidades y empresa (Region de Murcia, Spain) and 20800/PI/18 from Fundacion Seneca, Murcia. GSP was supported by grant BES-2016-077826 (Ministerio de Ciencia e Innovacion; Spain