1,520 research outputs found
Relação entre o ruído e as variáveis do processo produtivo na indústria extractiva a céu aberto
O ruído está intimamente associado a todos os processos industriais, sendo os ligados à indústria extractiva dos mais ruidosos. O presente artigo pretende
equacionar o estado da arte relativamente a relações entre a variável ocupacional – Ruído e as inerentes ao processo produtivo. Teve por base uma pesquisa
bibliográfica, desenvolvida através da combinação de um conjunto de palavras-chave, pré-definidas, diretamente ligadas às varáveis a tratar. Da pesquiza
efectuada pode-se concluir que as variáveis inerentes aos equipamentos e respetivas operações são as mais significativas. Foi também verificado que a
variável ruído se encontra muitas vezes associada a vibrações transmitidas aos sistemas mão-braço e corpo inteiro e a substâncias ototóxicas. Tal, entre
outras causas, faz com que aumente a dificuldade em classificar a PAIR como uma doença profissional. Por último, por envolver custos e redução na
produtividade, verificou-se ainda que os trabalhadores com PAIR são mais vulneráveis a acidentes de trabalho
XENO-Free production and recovery of human pluripotent stem cells using synthetic dissolvable microcarriers
The implementation of scalable culture platforms for the large-scale production of human pluripotent stem cells (hPSC) and their derivatives is mandatory to fulfill the requirement of obtaining large numbers of these cells for cell therapies and other in vitro biomedical applications, such as drug screening, toxicology assays and disease modeling. Recent progress includes the development of chemically-defined culture conditions for manufacturing of hPSC and their derivatives, namely the development of xeno-free microcarrier platforms to meet good manufacturing practice (GMP) quality requirements [1]. One challenge that remains to be addressed is the establishment of a robust, scalable, and cost-effective downstream processing for cell recovery and removal of the microcarriers. Since hPSC have the tendency to create multilayers of cells on the microcarriers, often forming very large cell-microcarrier aggregates, the process of cell recovery can be technically challenging and time consuming.
In this work, we developed a robust and efficient platform for large-scale production of hPSC using synthetic dissolvable microcarriers, which can be quickly dissolved by a non-proteolytic enzyme. This allows an easy cell recovery without the need of the microcarrier separation step, facilitating the downstream processing. Moreover, these synthetic microcarriers are sterile and ready-to-use, and are functionalized with the Synthemax® surface, based on a peptide-acrylate matrix designed for long-term support of hESC self-renewal [2].
hPSC were able to attach and grow on the dissolvable microcarriers and the expansion process was evaluated in a scalable stirred culture system. The cells growth performance on these microcarriers was comparable with the ones obtained when culturing hPSCs in non-dissolvable microcarriers (backbone of polystyrene coated with different ECM molecules), being possible to obtain 1.3x106 cells/mL during 5 days. Importantly, hPSCs cultured on these novel microcarriers were efficiently recovered without the need of the filtration step to separate the microcarriers from the cells and maintained their typical colony morphology and pluripotency-associated marker-expression after re-plating on tissue culture plates. Moreover, their potential for spontaneous differentiation into cells of the three embryonic germ layers was demonstrated through formation of embryoid bodies containing cells expressing typical markers of endoderm, ectoderm and mesoderm.
These novel synthetic dissolvable microcarriers allow an easy and efficient downstream processing for hPSCs recovery after expansion/differentiation, without compromising the quality of the cells (viability, potency and functionality), which are a major process breakthrough for stem cell manufacturing.
[1] Badenes SM, et al., “Defined Essential 8™ Medium and Vitronectin Efficiently Support Scalable Xeno-Free Expansion of Human Induced Pluripotent Stem Cells in Stirred Microcarrier Culture Systems”, PlosOne (2016), 11(3):e0151264.
[2] Melkoumian Z, et al, “Synthetic peptide-acrylate surfaces for long-term self-renewal and cardiomyocyte differentiation of human embryonic stem cells”, Nat Biotechnol (2010), 28(6): 606-10.
Acknowledgements: We acknowledge CORNING Incorporated for supplying the dissolvable microcarriers
Purification of plasmid DNA vectors by aqueous two-phase extraction and hydrophobic interaction chromatography
The current study explores the possibility of using a polyethyleneglycol(PEG)/ammonium sulphate aqueous two-phase system (ATPS) as an early step in a process for the purification of a model 6.1 kbp plasmid DNA (pDNA) vector. Neutralised alkaline lysates were fed directly to ATPS. Conditions were selected to direct pDNA towards the salt-rich bottom phase, so that this stream could be subsequently processed by hydrophobic interaction chromatography (HIC). Screening of the best conditions for ATPS extraction was performed using three PEG molecular weights (300, 400, 600) and varying the tie-line length, phase volume ratio and lysate load. For a 20 % (w/w) lysate load, the best results were obtained with PEG 600 using the shortest tie-line (38.16 % w/w). By further manipulating the system composition along this tie-line in order to obtain a top/bottom phase volume ratio of 9.3 (35 % w/w PEG 600, 6% w/w NH4)2SO4), it was possible to recover 100 % of pDNA in the bottom phase with a 3-fold increase in concentration. Further increase in the lysate load up to 40 %(w/w) with this system resulted in a 8-fold increase in pDNA concentration, but with a yield loss of 15 %. The ATPS extraction was integrated with HIC and the overall process compared with a previously defined process that uses sequential precipitations with isopropanol and ammonium sulphate prior to HIC. Although the final yield is lower in the ATPS-based process the purity grade of the final pDNA product is higher. This shows that it is possible to substitute the time-consuming two-step precipitation procedure by a simple ATPS extraction.Portuguese Ministry of Science and Technology - POCTI/BIO/47245/2002
A Pipeline for Clustering by Compression with Application to Patient Stratification in Spondyloarthritis
Funding Information: The authors acknowledge Fundação para a Ciência e Tecnologia, LASIGE Research Unit, ref. UIDB/00408/2020 and ref. UIDP/00408/2020 and Instituto de Telecomunicações Research Unit, ref. UIDB/50008/2020, and UIDP/50008/2020. The authors also acknowledge the Project PREDICT (PTDC/CCI-CIF/29877/2017), funded by Fundo Europeu de Desenvolvimento Regional (FEDER), through Programa Operacional Regional LISBOA (LISBOA2020), and by national funds, through Fundacção para a Ciência e Tecnologia (FCT), and projects MATISSE (DSAIPA/DS/0026/2019), MONET (PTDC/CCI-BIO/4180/2020) and SmartGlauco (PTDC/CTM-REF/2679/2020). Publisher Copyright: © 2023 by the authors.The normalized compression distance (NCD) is a similarity measure between a pair of finite objects based on compression. Clustering methods usually use distances (e.g., Euclidean distance, Manhattan distance) to measure the similarity between objects. The NCD is yet another distance with particular characteristics that can be used to build the starting distance matrix for methods such as hierarchical clustering or K-medoids. In this work, we propose Zgli, a novel Python module that enables the user to compute the NCD between files inside a given folder. Inspired by the CompLearn Linux command line tool, this module iterates on it by providing new text file compressors, a new compression-by-column option for tabular data, such as CSV files, and an encoder for small files made up of categorical data. Our results demonstrate that compression by column can yield better results than previous methods in the literature when clustering tabular data. Additionally, the categorical encoder shows that it can augment categorical data, allowing the use of the NCD for new data types. One of the advantages is that using this new feature does not require knowledge or context of the data. Furthermore, the fact that the new proposed module is written in Python, one of the most popular programming languages for machine learning, potentiates its use by developers to tackle problems with a new approach based on compression. This pipeline was tested in clinical data and proved a promising computational strategy by providing patient stratification via clusters aiding in precision medicine.publishersversionpublishe
Neural stem cells and cannabinoids in the spotlight as potential therapy for epilepsy
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Epilepsy is one of the most common brain diseases worldwide, having a huge burden in society. The main hallmark of epilepsy is the occurrence of spontaneous recurrent seizures, having a tremendous impact on the lives of the patients and of their relatives. Currently, the therapeutic strategies are mostly based on the use of antiepileptic drugs, and because several types of epilepsies are of unknown origin, a high percentage of patients are resistant to the available pharmacotherapy, continuing to experience seizures overtime. Therefore, the search for new drugs and therapeutic targets is highly important. One key aspect to be targeted is the aberrant adult hippocampal neurogenesis (AHN) derived from Neural Stem Cells (NSCs). Indeed, targeting seizure-induced AHN may reduce recurrent seizures and shed some light on the mechanisms of disease. The endocannabinoid system is a known modulator of AHN, and due to the known endogenous antiepileptic properties, it is an interesting candidate for the generation of new antiepileptic drugs. However, further studies and clinical trials are required to investigate the putative mechanisms by which cannabinoids can be used to treat epilepsy. In this manuscript, we will review how cannabinoid-induced modulation of NSCs may promote neural plasticity and whether these drugs can be used as putative antiepileptic treatment.This work was supported by IF/01227/2015 and UID/BIM/50005/2019, projeto financiado pela Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) através de Fundos do Orçamento de Estado. D.M.L. (PD/BD/141784/2018) and L.R.-R. (PD/BD/150344/2019) were in receipt of a fellowship from FCT. The authors are in hold of a H2020 Twinning Action from EU (EpiEpiNet).info:eu-repo/semantics/publishedVersio
Chitosan-Based Membranes for Skin Wound Repair in a Dorsal Fold Chamber Rat Model
Frequently, deep partial and full-thickness skin wounds do not spontaneously regenerate.
To restore the normal function of skin, epidermal and dermal components have to be supplied to
the wound bed by grafting various substrates. Available options are limited and frequently costly.
Herein, authors present a possible approach using 3D skin scaffolds capable of mimicking structure
and biological functions of the extracellular matrix, providing, in parallel, a good environment for
cell attachment, proliferation and differentiation. Low-molecular weight chitosan-based membranes
were prepared by freeze-drying and ionizing radiation techniques to be used as skin scaffolds. Poly
(vinyl alcohol), PVA, vinyl pyrrolidone, VP, and gelatin from cold water fish were incorporated.
Information regarding membranes’ physical-chemical properties from SEM analysis, swelling and
weight loss, together with biological response through in vitro assays (using Human Caucasian Fetal
Foreskin Fibroblast) allowed the selection of an optimized batch of membranes that was used as skin
scaffold in a dorsal rat model wound. The in vivo implantation assays (in Wistar rats) resulted in
very promising results: (i) healing process faster than control; (ii) good vascularization; (iii) viable
new tissues morphologically functional.info:eu-repo/semantics/publishedVersio
Solid-liquid phase equilibrium: in search of suitable PCMs for low temperature energy storage
Centro de Química Estrutural is a Research Unit funded by Fundação para a Ciência e Tecnologia through
projects UIDB/00100/2020 and UIDP/00100/2020.
• Institute of Molecular Sciences is an Associate Laboratory funded by FCT through project LA/P/0056/2020.
• M.C.M. Sequeira acknowledges the PhD grant funded by FCT ref. UI/BD/152239/2021.N/
Trypanosoma cruzi DNA replication includes the sequential recruitment of pre-replication and replication machineries close to nuclear periphery
In eukaryotes, many nuclear processes are spatially compartmentalized. Previously, we have shown that in Trypanosoma cruzi, an early-divergent eukaryote, DNA replication occurs at the nuclear periphery where chromosomes remain constrained during the S phase of the cell cycle. We followed Orc1/Cdc6, a pre-replication machinery component and the proliferating cell nuclear antigen (PCNA), a component of replication machinery, during the cell cycle of this protozoon. We found that, at the G(1) stage, TcOrc1/Cdc6 and TcPCNA are dispersed throughout the nuclear space. During the G(1)/S transition, TcOrc1/Cdc6 migrates to a region close to nuclear periphery. At the onset of S phase, TcPCNA is loaded onto the DNA and remains constrained close to nuclear periphery. Finally, in G(2), mitosis and cytokinesis, TcOrc1/Cdc6 and TcPCNA are dispersed throughout the nuclear space. Based on these findings, we propose that DNA replication in T. cruzi is accomplished by the organization of functional machineries in a spatial-temporal manner.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Universidade Federal de São Paulo, Parasitol Lab, Inst Butantan, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniv Fed Rio de Janeiro, Inst Biofis Carlos Chagas Filho, Lab Ultraestrutura Celular Hertha Meyer, BR-21941 Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Parasitol Lab, Inst Butantan, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc
Measuring health vulnerability: an interdisciplinary indicator applied to Mainland Portugal
Health promotion and inequality reduction are specific goals of the United Nations 2030 Agenda, which are interconnected with several dimensions of life. This work proposes a composite index SEHVI—socioeconomic health vulnerability index—to address Portuguese population socioeconomic determinants that affect health outcomes. Variables composing SEHVI are aligned with the sustainable development goals considering data and times series availability to enable progress monitoring, and variables adequacy to translate populations’ life conditions affecting health outcomes. Data for 35 variables and three periods were collected from official national databases. All variables are part of one of the groups: Health determinants (social, economic, cultural, and environmental factors) and health outcomes (mortality indicators). Variables were standardized and normalized by “Distance to a reference” method and then aggregated into the SEHVI formula. Several statistical procedures for validation of SEHVI revealed the internal consistency of the index. For all municipalities, SEHVI was calculated and cartographically represented. Results were analyzed by statistical tests and compared for three years and territory typologies. SEHVI differences were found as a function of population density, suggesting inequalities of communities’ life conditions and in vulnerability to health.info:eu-repo/semantics/publishedVersio
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