Diseño del sistema de control y automatización para una trituradora de endocarpio y mesocarpio de coco

Se dan a conocer los diferentes procesos llevados a cabo para la realización del diseño del sistema de control y automatización para una trituradora de endocarpio y mesocarpio de coco, iniciando por una inspección mecánica y eléctrica de la máquina, para llegar a identificar los diferentes problemas que ésta presenta. Ya definidos los diferentes problemas, se plantean las soluciones a seguir para mejorar el funcionamiento y rendimiento del mecanismo, además de la seguridad frente al operario. Posteriormente, se modela la trituradora por medio de programa SolidWorks, logrando analizar su funcionamiento, para posteriormente diseñar el sistema de control y automatización siguiendo la guía GEMMA. Por medio de un GRAFCET y su simulación en el software AUTOMGEN, se logra plantear un sistema de automatización que cuenta con un sistema de arranque y parada, información de funcionamiento por medio de luces y paro de emergencia. Todo esto conlleva a mejorar el funcionamiento, producción y seguridad de la máquina

Realisation of a hot carrier photovoltaic cell

The hot carrier solar cell is a heat engine; supplementing or supplanting the photovoltaic action of a traditional solar cell with a thermally driven current, analogous to a thermoelectric device. With this additional channel for energy extraction it is, in principle, possible for these cells to achieve efficiencies up to 85%, since the thermalization loss of high energy carriers is mitigated through their contribution to the heat current. In this thesis, three different hot carrier solar cell concepts are presented and experimentally investigated to probe their efficacy. Firstly, a hot carrier solar cell structure is presented, in which photogenerated carriers are extracted from a narrow band gap semiconductor to a wider bandgap semiconductor through a double barrier quantum well, providing energy selective extraction through resonant tunnelling. Current-voltage characteristics of this cell are presented along with time-resolved and temperature-dependent photoluminescence data, supporting the conclusion that this cell is operating as a hot carrier cell. Secondly, the idea of a metallic absorber for a solar cell is proposed, in order to provide ultra-high absorption of light (>99%) in metallic films thinner than 10nm. This idea is realised in two different cells, with silver and chromium absorbers. The absorption of light in the metal film, followed by extraction of heated electrons over a Schottky barrier, is demonstrated. Thirdly, the combination of these ideas is discussed, and a solar cell with a metallic absorber and selective extraction of heated electrons through resonant tunneling is realised. The current-voltage characteristics of all cells are modelled theoretically, and key signatures are revealed in both experimental and theoretical work showing the extraction of heated carriers.Open Acces

Germline mutations in the proof-reading domains of POLE and POLD1 predispose to colorectal adenomas and carcinomas.

Many individuals with multiple or large colorectal adenomas or early-onset colorectal cancer (CRC) have no detectable germline mutations in the known cancer predisposition genes. Using whole-genome sequencing, supplemented by linkage and association analysis, we identified specific heterozygous POLE or POLD1 germline variants in several multiple-adenoma and/or CRC cases but in no controls. The variants associated with susceptibility, POLE p.Leu424Val and POLD1 p.Ser478Asn, have high penetrance, and POLD1 mutation was also associated with endometrial cancer predisposition. The mutations map to equivalent sites in the proofreading (exonuclease) domain of DNA polymerases ɛ and δ and are predicted to cause a defect in the correction of mispaired bases inserted during DNA replication. In agreement with this prediction, the tumors from mutation carriers were microsatellite stable but tended to acquire base substitution mutations, as confirmed by yeast functional assays. Further analysis of published data showed that the recently described group of hypermutant, microsatellite-stable CRCs is likely to be caused by somatic POLE mutations affecting the exonuclease domain.post-print535 K

Germline loss-of-function variants in the base-excision repair gene MBD4 cause a Mendelian recessive syndrome of adenomatous colorectal polyposis and acute myeloid leukaemia

Inherited defects in base-excision repair (BER) predispose to adenomatous polyposis and colorectal cancer (CRC), yet our understanding of this important DNA repair pathway remains incomplete. By combining detailed clinical, histological and molecular profiling, we reveal biallelic germline loss-of-function (LOF) variants in the BER gene MBD4 to predispose to adenomatous polyposis and -uniquely amongst CRC predisposition syndromes- to myeloid neoplasms. Neoplasms from MBD4-deficient patients almost exclusively accumulate somatic CpG>TpG mutations, resembling mutational signature SBS1. MBD4-deficient adenomas harbour mutations in known CRC driver genes, although AMER1 mutations were more common and KRAS mutations less frequent. We did not find an increased risk for colorectal tumours in individuals with a monoallelic MBD4 LOF variant. We suggest that this condition should be termed MBD4-associated neoplasia syndrome (MANS) and that MBD4 is included in testing for the genetic diagnosis of polyposis and/or early-onset AM

Significance of Lactobacilli in Cheddar Cheese

End of Project ReportThe objectives of this project were to isolate and identify the non-starter lactobacilli in mature Cheddar cheese, identify strains which impart mature flavours to cheese and determine their role in developing cheese flavour. The main conclusions were as follows: Based on an analysis of 18 mature Cheddar cheeses, selected from 7 commercial manufacturers, non-starter lactic acid bacteria typically numbered, as expected, 106-108 per gram and were dominated (97 percent) by Lactobacillus paracasei. Although a small number of strains (typically 1 to 4) was found in each cheese there was considerable strain diversity in cheeses within as well as between manufacturing plants. When selected strains were investigated for survival and flavour enhancement when added (as starter adjuncts) with the normal starter cultures in Cheddar cheese manufacture, it was found that they remained dominant for up to 3 months of ripening. Commercial grading of these cheeses at 3 and 6 months confirmed that the added strains did modify flavour development and one (DPC 4103), in particular, had a beneficial effect. It was confirmed that two selected strains of non-starter lactobacilli were capable of metabolising citrate under the conditions of Cheddar cheese ripening and, consequently, if present in sufficient numbers, would influence flavour development. The work was greatly facilitated by the successful and novel adaptation of a modern rapid molecular technique (RAPD) for species and strain classification. In summary these studies found that one species of lactobacilli (Lb. paracasei) was the dominant non-starter lactic acid bacteria in mature Cheddar cheese. Although a wide variety of strains were identified, only a few were found in any particular cheese, suggesting their likely role in cheese flavour diversity even within the same manufacturing plant. This suggests the potential for flavour control or enhancement through the selective and controlled use of non-starter lactic acid bacteria. Preliminary investigations of the metabolism of those organisms supports this view and a follow-up study now in progress should provide greater clarity on this matter.Department of Agriculture, Food and the Marin

Unusual polymerization in the Li4C60 fulleride

Li4C60, one of the best representatives of lithium intercalated fullerides, features a novel type of 2D polymerization. Extensive investigations, including laboratory x-ray and synchrotron radiation diffraction, 13C NMR, MAS and Raman spectroscopy, show a monoclinic I2/m structure, characterized by chains of [2+2]-cycloaddicted fullerenes, sideways connected by single C-C bonds. This leads to the formation of polymeric layers, whose insulating nature, deduced from the NMR and Raman spectra, denotes the complete localization of the electrons involved in the covalent bonds.Comment: 7 pages, 6 figures, RevTex4, submitted to Phys. Rev.

Surface-Enhanced Raman Spectroscopy of Graphene Integrated in Plasmonic Silicon Platforms with Three-Dimensional Nanotopography

Integrating graphene with plasmonic nanostructures results in multifunctional hybrid systems with enhanced performance for numerous applications. In this work, we take advantage of the remarkable mechanical properties of graphene to combine it with scalable three-dimensional (3D) plasmonic nanostructured silicon substrates, which enhance the interaction of graphene with electromagnetic radiation. Large areas of femtosecond laser-structured arrays of silicon nanopillars, decorated with gold nanoparticles, are integrated with graphene, which conforms to the substrate nanotopography. We obtain Raman spectra at 488, 514, 633, and 785 nm excitation wavelengths, spanning the entire visible range. For all excitation wavelengths, the Raman signal of graphene is enhanced by 2–3 orders of magnitude, similarly to the highest enhancements measured to date, concerning surface-enhanced Raman spectroscopy of graphene on plasmonic substrates. Moreover, in contrast to traditional deposition and lithographic methods, the fabrication method employed here relies on single-step, maskless, cost-effective, rapid laser processing of silicon in water, amenable to large-scale fabrication. Finite-difference time-domain simulations elucidate the advantages of the 3D topography of the substrate. Conformation of graphene to Au-decorated silicon nanopillars enables graphene to sample near fields from an increased number of nanoparticles. Due to synergistic effects with the nanopillars, different nanoparticles become more active for different wavelengths and locations on the pillars, providing broad-band enhancement. Nanostructured plasmonic silicon is a promising platform for integration with graphene and other 2D materials, for next-generation applications of large-area hybrid nanomaterials in the fields of sensing, photonics, optoelectronics, and medical diagnostics

Germline MBD4 deficiency causes a multi-tumor predisposition syndrome

We report an autosomal recessive, multi-organ tumor predisposition syndrome, caused by bi-allelic loss-of-function germline variants in the base excision repair (BER) gene MBD4. We identified five individuals with bi-allelic MBD4 variants within four families and these individuals had a personal and/or family history of adenomatous colorectal polyposis, acute myeloid leukemia, and uveal melanoma. MBD4 encodes a glycosylase involved in repair of G:T mismatches resulting from deamination of 5'-methylcytosine. The colorectal adenomas from MBD4-deficient individuals showed a mutator phenotype attributable to mutational signature SBS1, consistent with the function of MBD4. MBD4-deficient polyps harbored somatic mutations in similar driver genes to sporadic colorectal tumors, although AMER1 mutations were more common and KRAS mutations less frequent. Our findings expand the role of BER deficiencies in tumor predisposition. Inclusion of MBD4 in genetic testing for polyposis and multi-tumor phenotypes is warranted to improve disease management. Keywords: 5′-methylcytosine deamination; colorectal cancer; mutational signature; mutator phenotype; polyposi