Experimental Realization of the Fuse Model of Crack Formation

In this work, we present an experimental investigation of the fuse model. Our main goal was to study the influence of the disorder on the fracture process. The experimental apparatus used consisted of an $L\times L$ square lattice with fuses placed on each bond of the lattice. Two types of materials were used as fuses: copper and steel wool wires. The lattice composed only by copper wires varied from a weakly disordered system to a strongly disordered one. The lattice formed only by steel wool wires corresponded to a strongly disordered one. The experimental procedure consisted of applying a potential difference V to the lattice and measuring the respective current I. The characteristic function $I(V)$ obtained was investigated in order to find the scaling law dependence of the voltage and the current on the system size $L$ when the disorder was changed. Our results show that the scaling laws are only verified for the disordered regime.Comment: 4 pages, 8 figures.ep

Caracterização de resíduos gerados em análises químicas de tecidos vegetais.

Este trabalho apresenta a caracterização dos resíduos gerados em análises químicas de tecidos vegetais do Laboratório de Análises de Solos e Plantas - LASP da Embrapa Amazônia Ocidental

Diagnóstico rápido participativo (DRP) como método de avaliação do programa de gerenciamento de resíduos laboratoriais (PGRL).

Na Embrapa, o DRP vem sendo utilizado pelo grupo de educação ambiental que adaptou o nome Diagnóstico Rural Participativo para Diagnóstico Rápido Participativo

Optimization of fermentation conditions for the production of curcumin by engineered Escherichia coli

Curcumin is a plant secondary metabolite with outstanding therapeutic effects. Therefore, there is a great interest in developing new strategies to produce this high-value compound in a cheaper and environmentally friendly way. Curcumin heterologous production in E. coli using artificial biosynthetic pathways was previously demonstrated using synthetic biology approaches. However, the culturing conditions to produce this compound were not optimized and so far only a two-step fermentation involving the exchange of the culture medium allowed to obtain high concentrations of curcumin, which limits its production at an industrial scale. In this study, the culturing conditions to produce curcumin were evaluated and optimized. In addition, it was concluded that E. coli BL21 allows to produce higher concentrations compared to E. coli K-12 strains. Different IPTG concentrations, time of protein expression induction and substrate type and concentration were also evaluated. The highest curcumin production obtained was 959.3 µM (95.93% of percent yield), which was 3.1-fold higher than the highest concentration previously reported. This concentration was obtained using a two-stage fermentation with LB and M9. Moreover, TB demonstrated to be a very interesting alternative medium to produce curcumin since it also led to high concentrations (817.7 µM). The use of this single fermentation medium represents an advantage at industrial scale and although the final production is lower than the one obtained with the LB-M9 combination, it leads to a significantly higher curcumin production in the first 24 h of fermentation. This study allowed obtaining the highest concentrations of curcumin reported so far in a heterologous organism and is of interest for all of those working with the heterologous production of curcuminoids, other complex polyphenolic compounds or plant secondary metabolites.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of the UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01- 0145-FEDER-006684) and under the scope of the Project MultiBiorefinery-Multi-purpose strategies for broadband agro-forest and fisheries by-products valorization: a step forward for a truly integrated biorefinery (POCI-01-0145-FEDER-016403). The authors also acknowledge financial support from BioTecNorte operation (NORTE-01-0145-FEDER-000004), funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte and the post-doctoral grant (UMINHO/BPD/37/2015) to J.L.R. funded by FCT.info:eu-repo/semantics/publishedVersio

Metagenomic sequencing unravels gene fragments with phylogenetic signatures of O2-tolerant NiFe membrane-bound hydrogenases in lacustrine sediment

Many promising hydrogen technologies utilising hydrogenase enzymes have been slowed by the fact that most hydrogenases are extremely sensitive to O2. Within the group 1 membrane-bound NiFe hydrogenase, naturally occurring tolerant enzymes do exist, and O2 tolerance has been largely attributed to changes in iron–sulphur clusters coordinated by different numbers of cysteine residues in the enzyme’s small subunit. Indeed, previous work has provided a robust phylogenetic signature of O2 tolerance [1], which when combined with new sequencing technologies makes bio prospecting in nature a far more viable endeavour. However, making sense of such a vast diversity is still challenging and could be simplified if known species with O2-tolerant enzymes were annotated with information on metabolism and natural environments. Here, we utilised a bioinformatics approach to compare O2-tolerant and sensitive membrane-bound NiFe hydrogenases from 177 bacterial species with fully sequenced genomes for differences in their taxonomy, O2 requirements, and natural environment. Following this, we interrogated a metagenome from lacustrine surface sediment for novel hydrogenases via high-throughput shotgun DNA sequencing using the Illumina™ MiSeq platform. We found 44 new NiFe group 1 membrane-bound hydrogenase sequence fragments, five of which segregated with the tolerant group on the phylogenetic tree of the enzyme’s small subunit, and four with the large subunit, indicating de novo O2-tolerant protein sequences that could help engineer more efficient hydrogenases

Anatomía comparada de los fascioláridos Pustulatirus ogum y Hemipolygona beckyae de Brasil (Gastropoda: Buccinoidea: Peristerniinae)

The Brazilian species Pustulatirus ogum and Hemipolygona beckyae were examined, and certain morphological characters were described. Both species were originally assigned to the genus Latirus, considered as a heterogeneous complex. The radulae of both species are like that which characterizes Latirus, in which the innermost cusp of the rachidian tooth is well developed but always smaller than the other cusps. This feature differs from Leucozonia, in which this cusp is reduced or absent. The penis tapers terminally, and the tapered part may be long (more than half the total penis length), as in H. beckyae, or very short (less than half the total penis length), as in P. ogum. The anatomical data observed in both species are discussed under the framework of fasciolariid systematics and they appear to be widespread among other fasciolariid species. For this reason, to date, the soft-part features here provided and those known from previously studied species of Latirus are not useful for delineating precise generic diagnoses.Se describe la morfología y anatomía de las especies brasileñas Pustulatirus ogum y Hemipolygona beckyae. Ambas especies han sido tradicionalmente asignadas al género Latirus, que en la actualidad se considera que agrupa a un conjunto heterogéneo de especies. Las rádulas de ambas especies son como la que caracteriza a Latirus, con la cúspide más interna del diente raquídeo bien desarrollada y siempre menor que las otras cúspides. Esta característica difiere de la que presentan las especies del género Leucozonia, en las que esta cúspide está reducida o ausente. El pene se estrecha en su parte terminal, y la parte cónica puede ser larga (más de la mitad de la longitud total del pene), como en H. beckyae, o muy corta (menos de la mitad de la longitud total del pene), como en P. ogum. Los caracteres morfológicos observados en ambas especies se discuten en el marco de la sistemática de los Fasciolariidae y parecen estar ampliamente distribuidos en otras especies de fascioláridos. Por ello, hasta la fecha, las características de las partes blandas del animal aquí descritas y las conocidas previamente de otras especies de Latirus no se consideran de utilidad para la diagnosis de los géneros en esta familia

Multitask and transfer learning for cardiac abnormality detection in heart sounds

We present a deep learning model for the automatic detection of murmurs and other cardiac abnormalities from the analysis of digital recordings of cardiac auscultations. This approach was developed in the context of the George B. Moody PhysioNet Challenge 2022. More precisely, we consider multi-objective neural networks, with several Transformer blocks at their core, trained to perform 3 distinct tasks simultaneously: murmur detection, outcome classification and audio signal segmentation. We also perform pre-training with the 2016’s Challenge data. We entered the challenge under the team name matLisboa. Our results on the hidden test dataset were: Murmur score (weighted accuracy): 0.735 (ranked 15th). Outcomes score (cost): 12593 (ranked 16th).info:eu-repo/semantics/publishedVersio

Anaphylaxis in Pregnancy: a Rare Cause of Neonatal Mortality

Anaphylaxis is a rare condition in pregnancy. Drugs are the aetiological agents most often implicated. Maternal anaphylaxis can lead to significant fetal morbidity and even mortality if uterine perfusion and maternal oxygenation are compromised. Significant risk of neonatal neurological damage or death can occur even when the maternal clinical outcome is favourable. The authors present the case of a newborn, born at gestational age of 29 weeks, who died at 11 days of life with hypoxic-ischaemic cerebral injuries as a consequence of maternal anaphylaxis following the administration of amoxicillin in the community setting.info:eu-repo/semantics/publishedVersio

Cloning, expression and characterization of UDP-glucose dehydrogenases

Uridine diphosphate-glucose dehydrogenase (UGD) is an enzyme that produces uridine diphosphate-glucuronic acid (UDP-GlcA), which is an intermediate in glycosaminoglycans (GAGs) production pathways. GAGs are generally extracted from animal tissues. Efforts to produce GAGs in a safer way have been conducted by constructing artificial biosynthetic pathways in heterologous microbial hosts. This work characterizes novel enzymes with potential for UDP-GlcA biotechnological production. The UGD enzymes from Zymomonas mobilis (ZmUGD) and from Lactobacillus johnsonii (LbjUGD) were expressed in Escherichia coli. These two enzymes and an additional eukaryotic one from Capra hircus (ChUGD) were also expressed in Saccharomyces cerevisiae strains. The three enzymes herein studied represent different UGD phylogenetic groups. The UGD activity was evaluated through UDP-GlcA quantification in vivo and after in vitro reactions. Engineered E. coli strains expressing ZmUGD and LbjUGD were able to produce in vivo 28.4 µM and 14.9 µM UDP-GlcA, respectively. Using S. cerevisiae as the expression host, the highest in vivo UDP-GlcA production was obtained for the strain CEN.PK2-1C expressing ZmUGD (17.9 µM) or ChUGD (14.6 µM). Regarding the in vitro assays, under the optimal conditions, E. coli cell extract containing LbjUGD was able to produce about 1800 µM, while ZmUGD produced 407 µM UDP-GlcA, after 1 h of reaction. Using engineered yeasts, the in vitro production of UDP-GlcA reached a maximum of 533 µM using S. cerevisiae CEN.PK2-1C_pSP-GM_LbjUGD cell extract. The UGD enzymes were active in both prokaryotic and eukaryotic hosts, therefore the genes and expression chassis herein used can be valuable alternatives for further industrial applications.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. The authors acknowledge FCT for funding MRC doctoral grant SFRH/BD/132998/2017.info:eu-repo/semantics/publishedVersio

Ganho de peso bovino em resteva de arroz irrigado na safra de 2009/2010 na Embrapa Pecuária Sul.

bitstream/item/31962/1/DT-102online.pd