86 research outputs found
Transducers for extracellular signal measurements
Dissertação de mestrado, Engenharia EletrĂłnica e TelecomunicaçÔes, Faculdade de CiĂȘncias e Tecnologia, Universidade do Algarve, 2017The objective of this thesis is to develop and optimize bioelectronic sensing devices for
extracellular signal measurements in vitro. Ultra-sensitive electrodes were fabricated and
electrically characterized. A signal detection limit defined by a noise level of 0.3-0.4 ÎŒV for a
bandwidth of 0.1 - 12.5 Hz was achieved. To obtain this high sensitivity, large area (4 mm2)
electrodes were used. The electrode surface is also micro-structured with an array of gold and
polymer mushroom-like shapes to further enhance the active area. In comparison with a flat
gold surface the micro-structured polymer surface increases the capacitance of the
electrode/electrolyte interface by six times.
The role of the electrode impedance on the signal quality is discussed in detail. The
impedance is modeled by an electrical equivalent circuit and a methodology is presented to
extract individual circuit parameters.
The electrode low impedance and low noise enable the detection of weak and low
frequency quasi-periodic signals produced by astrocytes populations that thus far had remained
inaccessible using conventional extracellular electrodes. Signals with 5 ÎŒV in amplitude and
lasting for 5-10 s were measured with a peak-to-peak signal-to-noise ratio of 10.
The microstructured electrodes were also used to stimulate electrical activity in glioma cell
cultures and astrocytes populations using a train of voltages pulses.
The electrodes and the methodology developed here can be used as an ultrasensitive
electrophysiological tool to reveal the synchronization dynamics of ultra-slow ionic signaling
between non-electrogenic cells.Esta tese tem o objetivo de desenvolver e otimizar componentes eletrĂłnicos para a
deteção de sinais extracelulares in vitro. ElĂ©trodos ultrassensĂveis foram fabricados e
caracterizados eletricamente. O nĂvel de deteção mĂnimo alcançado foi definido pelo ruĂdo
tĂ©rmico fundamental gerado pelo sensor. Este ruĂdo Ă© de aproximadamente 0,3-0,4 ÎŒV para
uma largura de banda de 0,1 - 12,5 Hz. Para obter este nĂvel de deteção utilizaram-se elĂ©trodos
de grande ĂĄrea (4 mm2). A superfĂcie do elĂ©trodo tambĂ©m Ă© microestruturada com uma sĂ©rie
de formas semelhantes a cogumelos para baixar a impedùncia do elétrodo. Em comparação
com uma superfĂcie plana de ouro, a superfĂcie microestrutura da aumenta em seis vezes a
capacidade da interface elĂ©trodo/solução eletrolĂtica
O papel da impedùncia do elétrodo na qualidade do sinal é discutido em detalhe na tese.
A impedùncia é modelada por um circuito elétrico equivalente. à também apresentada uma
metodologia para extrair os parĂąmetros individuais que caracterizam o sensor.
O elĂ©trodo de baixa impedĂąncia e baixo nĂvel de ruĂdo possibilita a deteção de sinais
fracos e de baixa frequĂȘncia produzidos por populaçÔes de astrĂłcitos. AtĂ© agora estes sinais
permaneceram inacessĂveis usando tĂ©cnicas de medida mais convencionais. Sinais com 5 ÎŒV
em amplitude e com duração de 5-10 s foram medidos com uma relação sinal/ruĂdo de pico-apico
de 10.
Os elétrodos microestruturados também foram utilizados para estimular a atividade
elétrica em culturas de células glioma e populaçÔes de astrócitos.
Esta tese propÔe que os elétrodos e a metodologia aqui desenvolvida podem ser usados
como uma ferramenta eletrofisiolĂłgica ultrassensĂvel para revelar a dinĂąmica de sincronização
da sinalização iónica ultra-lenta (na escala de vårios segundos e minutos) entre células não
eletrogéneas
Tratamento de auto limpeza de materiais tĂȘxteis sintĂ©ticos
O presente trabalho tem como objectivo estudar a degradação de matérias orgùnicas (e.g.
corante tĂȘxtil) sobre substratos tĂȘxteis sintĂ©ticos, tecido de poliĂ©ster, tecido de
poliĂ©ster/policloreto de vinilo (PVC) e filmes de PVC. Para o efeito, os substratos tĂȘxteis
foram tratados com nanopartĂculas de diĂłxido titĂąnio, usando tĂ©cnicas fĂsicas e quĂmicas.
Assim iniciou-se o estudo da actividade fotocatalĂtica do diĂłxido de titĂąnio na presença de
radiação (UV), verificando-se que o corante Astrazon BN sofre uma decomposição efectiva. A
escolha de um corante tĂȘxtil como exemplo de uma matĂ©ria orgĂąnica prende-se com o facto
de facilmente se poder fazer uma avaliação colorimétrica da sua degradação durante o
trabalho experimental.
Da literatura sabe-se que o diĂłxido de titĂąnio consegue degradar a generalidade de compostos
orgĂąnicos, podendo inferir-se que este agente seja adequado para enfrentar os poluentes do
mundo exterior que se possam depositar Ă sua superfĂcie dos objectos, exibindo assim um
comportamento auto-limpante desejado.
Ao longo deste trabalho apresentam-se, discutem-se e comentam-se os resultados da
degradação efectiva ao longo do tempo de um corante de aplicação tĂȘxtil. Os resultados
obtidos são bastante promissores, de forma a se pensar que este método é viåvel em
acabamentos de auto-limpeza de materiais e mesmo no tratamento de efluentes orgĂąnicos.The present work aims to study the degradation of organic materials (eg textile dye) on
synthetic textile substrates, polyester fabric, polyester/polyvinyl chloride (PVC) fabric and
PVC films. For this, the textile substrates were treated with nanoparticles of titanium
dioxide, using physical and chemical techniques.
Thus the study of the photocatalytic activity of titanium dioxide in the presence of UV
radiation was done, thus verifying that the Astrazon BN dye undergoes an effective
decomposition. The choice of a textile dye as an example of organic matter relates to the
fact that one can easily make a colorimetric evaluation of its degradation during the
experimental work.
From literature it is known that titanium dioxide can degrade the majority of organic
compounds, which can be inferred that this agent is adequate to address the pollutants of the
outside world that may be placed on the surface of objects, thus exhibiting a required selfcleaning behaviour.
Throughout this paper we present, discuss and comment the results of the actual degradation
over time of a textile dye. The results are very promising, so we think that this method is
feasible in of self-cleaning finishing of materials and even in the treatment of organic
wastewater
Fractional flow reserve-guided strategy in acute coronary syndrome. a systematic review and meta-analysis
Background: There are limited data on the prognosis of deferral of lesion treatment in patients with acute coronary syndrome (ACS) based on fractional flow reserve (FFR). Objectives: To provide a systematic review of the current evidence on the prognosis of deferred lesions in ACS patients compared with deferred lesions in non-ACS patients, on the basis of FFR. Methods: We searched Medline, EMBASE, and the Cochrane Library for studies published between January 2000 and September 2017 that compared prognosis of deferred revascularization of lesions on the basis of FFR in ACS patients compared with non-ACS patients. We conducted a pooled relative risk meta-analysis of four primary outcomes: mortality, cardiovascular (CV) mortality, myocardial infarction (MI) and target-vessel revascularization (TVR). Results: We identified 7 studies that included a total of 5,107 patients. A pooled meta-analysis showed no significant difference in mortality (relative risk [RR] = 1.44; 95% CI, 0.9â2.4), CV mortality (RR = 1.29; 95% CI = 0.4â4.3) and TVR (RR = 1.46; 95% CI = 0.9â2.3) after deferral of revascularization based on FFR between ACS and non-ACS patients. Such deferral was associated with significant additional risk of MI (RR = 1.83; 95% CI = 1.4â2.4) in ACS patients. Conclusion: The prognostic value of FFR in ACS setting is not as good as in stable patients. The results demonstrate an increased risk of MI but not of mortality, CV mortality, and TVR in ACS patients.publishe
Alteplase for Massive Pulmonary Embolism after Complicated Pericardiocentesis
Background: The occurrence of a high-risk pulmonary embolism (PE) within 48 hours of a complicated pericardiocentesis to remove a
haemorrhagic pericardial effusion, is an uncommon clinical challenge.
Case summary: The authors report the case of a 75-year-old woman who presented with signs of imminent cardiac tamponade due to recurring
idiopathic pericardial effusion. The patient underwent pericardiocentesis that was complicated by the loss of 1.5 litres of blood. Within 48
hours, the patient had collapsed with clear signs of obstructive shock. This was a life-threating situation so alteplase was administered after
cardiac tamponade and hypertensive pneumothorax had been excluded. CT chest angiography later confirmed bilateral PE. The patient
achieved haemodynamic stability less than an hour after receiving the alteplase. However, due to the high risk of bleeding, the medical team
suspended the thrombolysis protocol and switched to unfractionated heparin within the hour. The cause of the PE was not identified despite
extensive study, but after 1 year of follow-up the patient remained asymptomatic.
Discussion: Despite the presence of a contraindication, the use of thrombolytic therapy in obstructive shock after exclusion of hypertensive
pneumothorax can be life-saving, and low-dose thrombolytic therapy may be a valid option in such cases
Caracterização molecular dos doentes portugueses com miocardiopatia dilatada
Introduction: Dilated cardiomyopathy (DCM) is a disease of the heart muscle characterized
by ventricular dilatation and impaired systolic function. Familial forms account for 30-50%
of cases. Autosomal dominant inheritance is the predominant pattern of transmission. Causal
genetic variants have been identified in several genes and molecular diagnosis has implications
for genetic counseling and risk stratification.
Objective: We aimed to estimate the frequency of genetic variants and the molecular basis of
DCM in Portugal.
Methods: We performed a multicenter study of unrelated patients, recruited between 2013 and
2014. Variants in 15 genes were screened using PCR with direct sequencing (next-generation
sequencing with at least 30-fold coverage combined with Sanger sequencing).
Results: A total of 107 patients were included, 64 (60%) men, mean age at diagnosis
38±13 years, with 48 (45%) familial cases. In total, 31 rare variants in eight genes (mainly
in MYBPC3, TNNT2 and LMNA) were identified, in 28 patients (26%). Only four variants had been
previously described in association with DCM, 11 with hypertrophic cardiomyopathy, and nine
variants were novel. Four variants were likely pathogenic and the remainder were of uncertain
significance. We found no major differences in the main clinical and imaging characteristics
between patients with or without rare variants and patients with likely pathogenic variants.
Conclusions: Our results reflect the complexity and diversity of DCM genetics. For better inter-pretation of the pathogenicity of the variants found and their causative roles in DCM, molecularcascade screening of families is imperative. Further insight into genotype-phenotype correla-tions and risk stratification is desirable.Introdução: A miocardiopatia dilatada (MCD) Ă© uma doença do mĂșsculo cardĂaco caracterizada por dilatação ventricular e compromisso da função sistĂłlica. As formas familiares sĂŁo responsĂĄveis por 30 a 50% dos casos. O padrĂŁo de hereditariedade predominante Ă© o autossĂłmicodominante. Variantes genĂ©ticas causais foram identificadas em vĂĄrios genes e o diagnĂłsticomolecular tem implicacžÔes para o aconselhamento genĂ©tico e estratificação de risco.Objetivo: Avaliar a base molecular da MCD em Portugal.MĂ©todos: Estudo multicĂȘntrico de doentes nĂŁo relacionados, recrutados entre 2013 e 2014.Foram analisados 15 genes, atravĂ©s da tĂ©cnica de PCR com sequenciacžão direta (NGS com pelomenos uma cobertura de 30 vezes combinada com sequenciacžão de Sanger).Resultados: Foram incluĂdos 107 pacientes, 64 (60%) homens, idade mĂ©dia ao diagnĂłstico de38 ± 13 anos, com 48 (45%) casos familiares. Foram identificadas 31 variantes raras, em oitogenes, (principalmente MYBPC3, TNNT2 e LMNA) em 28 pacientes (26%). Apenas quatro variantestinham sido previamente descritas em associacžão com MCD, 11 com miocardiopatia hipertrĂł-fica e nove variantes eram novas. Quatro variantes foram classificadas como provavelmentepatogĂ©nicas e as restantes de significado incerto. NĂŁo encontrĂĄmos diferencžas significativas nasprincipais caracterĂsticas clĂnicas e imagiolĂłgicas entre doentes com ou sem variantes raras e doentes com variantes provavelmente patogĂ©nicas.
ConclusĂ”es: Estes resultados refletem a complexidade e diversidade genĂ©tica da MCD. Para uma melhor interpretação da patogenicidade das variantes e potencial causalidade, o rastreio molecular das famĂlias Ă© imperativo. Uma visĂŁo mais aprofundada das correlaçÔes genĂłtipo-fenĂłtipo e da estratificação de risco Ă© desejĂĄvel
A hybrid bi-objective optimization approach for joint determination of safety stock and safety time buffers in multi-item single-stage industrial supply chains
In material requirements planning (MRP) systems, safety stock and safety time are two well-known inventory buffering strategies to protect against supply and demand uncertainties. While the role of safety stocks in coping with uncertainty is well studied, safety time has received only scarce attention in the supply chain management literature. Particularly, most previous operations research models have typically considered the use of such inventory buffers in a separate fashion, but not together. Here, we propose a decision support system (DSS) to address the problem of integrating optimal safety stock and safety time decisions at the component level, in multi-supplier multi-item single-stage industrial supply chains under dynamic demands and stochastic lead times. The DSS is based on a hybrid bi-objective optimization approach that simultaneously optimizes upstream inventory holding costs and ÎČ-service levels, suggesting multiple non-dominated Pareto-optimal solutions to
decision-makers. We further explore a weighted closed-form analytical expression to select a single Pareto-optimal point from a set of non-dominated solutions, thereby enhancing the practical application of the proposed DSS. We describe the implementation of our approach in a major automotive electronics company operating under a myriad of components with dynamic demand, uncertain supply and requirements plans with different degrees of sparsity. We show the potential of our approach to improve ÎČ-service levels while minimizing inventory-related costs. The results suggest that, in certain cases, it appears to be more cost-effective to combine safety stock with safety time compared to considering each inventory buffer independently.This work has been supported by the European Structural and Investment Funds in the FEDER component,
through the Operational Competitiveness and Internationalization Pro-gram (COMPETE 2020) [Project No. 39479, Funding reference: POCI-01â0247-FEDER-39479]
Clinical and epidemiological features of hospitalized and ambulatory patients with human monkeypox infection: a retrospective observational study in Portugal
© 2022 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 (https://creativecommons.org/licenses/by/4.0/).Monkeypox, a neglected and re-emergent zoonotic disease caused by monkeypox virus (MPXV) infection, has been endemic in Central and Western Africa for decades. More recently, an outbreak has spread to a global level, occurring in sites with no previous reported cases and being clustered among men who have sex with men, suggesting new modes of transmission. There is an urgent need for research for a better understanding of the genomic evolution and changing epidemiology of the Orthopoxvirus group. Our work aimed to characterize the clinical and epidemiological features of a cohort of patients with MPXV infection in a Portuguese hospital, admitted between 5 May and 26 July 2022. In this retrospective observational study, aggregate data of a case series on the presentation, clinical course, and outcomes of confirmed MPXV infections are reported. The study included 40 men and 1 woman, with a mean age of 37.2 years old; 92.7% identified as men who have sex with men, 90.2% had unprotected sex or sex with multiple or anonymous partners in the previous month, and 39.0% reported to have had sex with an MPXV-confirmed case; 59.5% had previously known human immunodeficiency virus (HIV) infection, all of whom were under antiretroviral therapy, and no patients had acquired immunodeficiency syndrome (AIDS) criteria. About a quarter of patients were observed only a week after symptom onset. All patients had skin or mucosal lesions and the anogenital region was the most frequent lesion site. There were no statistically significant clinical differences between HIV-positive and negative individuals. Four patients were admitted to the inpatient clinic, two of whom had proctitis with difficult-to-manage anal pain. There were no reported deaths. Our findings suggest the sexual route as a relevant mode of transmission of MPXV and confirm the mostly benign presentation of this disease.The writing of this manuscript received the support of Fundação para a CiĂȘncia e a Tecnologia, grant numbers UIDB/04295/2020 and UIDP/04295/2020info:eu-repo/semantics/publishedVersio
Role of two Triatoma (Hemiptera: Reduviidae: Triatominae) species in the transmission of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) to man in the West Coast of Mexico
A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencing
Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management.
Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org.
Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.Peer Reviewe
Database Survey of Anti-Inflammatory Plants in South America: A Review
Inflammation is a complex event linked to tissue damage whether by bacteria, physical trauma, chemical, heat or any other phenomenon. This physiological response is coordinated largely by a variety of chemical mediators that are released from the epithelium, the immunocytes and nerves of the lamina propria. However, if the factor that triggers the inflammation persists, the inflammation can become relentless, leading to an intensification of the lesion. The present work is a literature survey of plant extracts from the South American continent that have been reported to show anti-inflammatory activity. This review refers to 63 bacterial families of which the following stood out: Asteraceae, Fabaceae, Euphorbiaceae, Apocynaceae and Celastraceae, with their countries, parts used, types of extract used, model bioassays, organisms tested and their activity
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