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1.
Artigo em Inglês | MEDLINE | ID: mdl-38429541

RESUMO

AIMS: To characterize the register of a secondary diagnosis of mental illnesses in all chronic obstructive pulmonary disease (COPD) hospitalizations registered in Portugal from 2008 to 2015 and explore their impact on hospitalization outcomes. METHODS: A retrospective observational study was conducted. Hospitalizations of patients with at least 40 years old, discharged between 2008 and 2015 with a primary diagnosis of COPD (ICD-9-CM codes 491.x, 492.x and 496) were retrieved from a national administrative database. Comorbid psychiatric diagnoses were identified and defined by the HCUP Clinical Classification Software (CCS) category codes 650-670 (excluding 662). Length of hospital stay (LoS), admission type, in-hospital mortality, and estimated hospital charges were analyzed according to psychiatric diagnostic categories using sex and age-adjusted models. RESULTS: Of 66,661 COPD hospitalizations, 25,869 (38.8%) were episodes with a registered psychiatric comorbidity. These were more likely to correspond to younger inpatients (OR = 2.16, 95%CI 2.09-2.23; p < 0.001), to stay longer at the hospital (aOR = 1.08, 95%CI 1.05-1.12; p < 0.001), to incur in higher estimated hospital charges (aOR = 1.37, 95%CI 1.33-1.42; p < 0.001) and to be urgently admitted (aOR = 1.33, 95%CI 1.23-1.44; p < 0.001). After adjustment for age, in-hospital mortality was lower for episodes with psychiatric diagnoses (aOR = 0.90; 95%CI 0.84-0.96; p < 0.001), except for organic and neurodegenerative diseases category and developmental disorders, intellectual disabilities and disorders usually diagnosed in infancy, childhood, or adolescence category. DISCUSSION: These findings corroborate the additional burden placed by psychiatric disorders on COPD hospitalizations, highlighting the importance of individualizing care to address these comorbidities and minimize their impact on treatment outcomes.

2.
Sensors (Basel) ; 23(24)2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38139704

RESUMO

The emergence of Industry 4.0 and 5.0 technologies has enabled the digital transformation of various processes and the integration of sensors with the internet. Despite these strides, many industrial sectors still rely on visual inspection of physical processes, especially those employing analog gauges. This method of monitoring introduces the risk of human errors and inefficiencies. Automating these processes has the potential, not only to boost productivity for companies, but also potentially reduce risks for workers. Therefore, this paper proposes an end-to-end solution to digitize analog gauges and monitor them using computer vision through integrating them into an IoT architecture, to tackle these problems. Our prototype device has been designed to capture images of gauges and transmit them to a remote server, where computer vision algorithms analyze the images and obtain gauge readings. These algorithms achieved adequate robustness and accuracy for industrial environments, with an average relative error of 0.95%. In addition, the gauge data were seamlessly integrated into an IoT platform leveraging computer vision and cloud computing technologies. This integration empowers users to create custom dashboards for real-time gauge monitoring, while also enabling them to set thresholds, alarms, and warnings, as needed. The proposed solution was tested and validated in a real-world industrial scenario, demonstrating the solution's potential to be implemented in a large-scale setting to serve workers, reduce costs, and increase productivity.

4.
Ecol Evol ; 12(8): e9239, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36052301

RESUMO

Carnivore intraguild dynamics depend on a complex interplay of environmental affinities and interspecific interactions. Context-dependency is commonly expected with varying suites of interacting species and environmental conditions but seldom empirically described. In South Africa, decentralized approaches to conservation and the resulting multi-tenure conservation landscapes have markedly altered the environmental stage that shapes the structure of local carnivore assemblages. We explored assemblage-wide patterns of carnivore spatial (residual occupancy probability) and temporal (diel activity overlap) co-occurrence across three adjacent wildlife-oriented management contexts-a provincial protected area, a private ecotourism reserve, and commercial game ranches. We found that carnivores were generally distributed independently across space, but existing spatial dependencies were context-specific. Spatial overlap was most common in the protected area, where species occur at higher relative abundances, and in game ranches, where predator persecution presumably narrows the scope for spatial asymmetries. In the private reserve, spatial co-occurrence patterns were more heterogeneous but did not follow a dominance hierarchy associated with higher apex predator densities. Pair-specific variability suggests that subordinate carnivores may alternate between pre-emptive behavioral strategies and fine-scale co-occurrence with dominant competitors. Consistency in species-pairs diel activity asynchrony suggested that temporal overlap patterns in our study areas mostly depend on species' endogenous clock rather than the local context. Collectively, our research highlights the complexity and context-dependency of guild-level implications of current management and conservation paradigms; specifically, the unheeded potential for interventions to influence the local network of carnivore interactions with unknown population-level and cascading effects.

5.
Cureus ; 14(4): e24590, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35664385

RESUMO

Objective To analyze the prevalence and clinical progression of primary biliary cholangitis (PBC) in patients with primary Sjögren's syndrome (pSS) and possible associations between biochemical and immunological features and the development of PBC. Methods We retrospectively reviewed a cohort of 115 pSS patients followed up in an outpatient clinic from 1987 to 2020, without a history of liver disease, and looked for the presence of PBC through analysis of several biochemical, immunological, and histologic characteristics. Results Twenty patients (17.4%) had chronic cholestatic liver biochemistry. After exclusion of extrahepatic liver disease by abdominal ultrasound, 13 of them were tested for antimitochondrial autoantibodies (AMA) detected by indirect immunofluorescence (IF), of which five tested positive, fulfilling the diagnostic criteria for PBC. Three of the five PBC patients and three of the eight chronic cholestasis AMA-negative patients were further investigated with liver biopsy, which showed features of PBC in all three PBC patients and in one of the chronic cholestasis AMA-negative patients, allowing for the diagnosis of AMA-negative PBC in the latter. The remaining two AMA-negative patients had liver histology compatible with autoimmune hepatitis and unspecific findings, respectively. Overall, six (5.2%) patients with pSS had AMA-positive PBC (n=5) or AMA-negative PBC (n=1). Comparing immunological characteristics between PBC and non-PBC patients, we found that PBC patients had a higher mean maximum erythrocyte sedimentation rate (ESR) during follow-up than patients without PBC. All PBC patients were treated with ursodeoxycholic acid (UDCA) and after treatment with UDCA, only one patient showed biochemical and clinical progression of PBC, with increasing alkaline phosphatase and total bilirubin levels, eventually progressing to cirrhosis. Conclusions Among patients with pSS, PBC had an overall prevalence of six of 115 (5.2%). Higher ESR was a feature associated with PBC patients. In our cohort, after initiation of UDCA treatment, PBC showed predominantly slow progress, with only one patient progressing to cirrhosis during follow-up.

6.
J Cardiol Cases ; 25(6): 400-403, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35154518

RESUMO

Kounis syndrome is an acute coronary syndrome occurring in the setting of a hypersensitivity reaction. It occurs as a consequence of mast-cell activation and degranulation causing coronary artery spasm, atherosclerotic plaque erosion, or stent thrombosis. We report the case of a man who presented to the emergency department with typical angina that started 20 minutes after coronavirus disease 2019 (COVID-19) vaccine administration. Electrocardiogram showed inferior ST-elevation myocardial infarction, and coronary angiography confirmed right coronary artery stent thrombosis. Five months before, he had an acute coronary syndrome after influenza vaccine administration. Both vaccines share a common excipient, polysorbate 80. Considering the reproducibility of the reaction and the temporal association between vaccine administration and coronary events, a hypersensitivity reaction to polysorbate 80 was admitted and the patient was instructed to further avoid drugs containing it. To our knowledge, this constitutes the first reported case of type 3 Kounis syndrome after COVID-19 vaccine administration. Kounis syndrome is an uncommon disease, often undiagnosed. Its recognition and proper management are crucial to prevent future events. .

7.
Adv Mater ; 34(8): e2107205, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34873762

RESUMO

Relative humidity is simultaneously a sensing target and a contaminant in gas and volatile organic compound (VOC) sensing systems, where strategies to control humidity interference are required. An unmet challenge is the creation of gas-sensitive materials where the response to humidity is controlled by the material itself. Here, humidity effects are controlled through the design of gelatin formulations in ionic liquids without and with liquid crystals as electrical and optical sensors, respectively. In this design, the anions [DCA]- and [Cl]- of room temperature ionic liquids from the 1-butyl-3-methylimidazolium family tailor the response to humidity and, subsequently, sensing of VOCs in dry and humid conditions. Due to the combined effect of the materials formulations and sensing mechanisms, changing the anion from [DCA]- to the much more hygroscopic [Cl]- , leads to stronger electrical responses and much weaker optical responses to humidity. Thus, either humidity sensors or humidity-tolerant VOC sensors that do not require sample preconditioning or signal processing to correct humidity impact are obtained. With the wide spread of 3D- and 4D-printing and intelligent devices, the monitoring and tuning of humidity in sustainable biobased materials offers excellent opportunities in e-nose sensing arrays and wearable devices compatible with operation at room conditions.

8.
Ecology ; 103(2): e03600, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34816428

RESUMO

Theory on intraguild killing (IGK) is central to mammalian carnivore community ecology and top-down ecosystem regulation. Yet, the cryptic nature of IGK hinders empirical evaluations. Using a novel data source - online photographs of interspecific aggression between African carnivores - we revisited existing predictions about the extent and drivers of IGK. Compared with seminal reviews, our constructed IGK network yielded 10 more species and nearly twice as many interactions. The extent of interactions increased 37% when considering intraguild aggression (direct attack) as a precursor of killing events. We show that IGK occurs over a wider range of body-mass ratios than predicted by standing competition-based views, with highly asymmetrical interactions being pervasive. Evidence that large species, particularly hypercarnivore felids, target sympatric carnivores with a wide range of body sizes suggests that current IGK theory is incomplete, underestimating alternative competition pathways and the role of predatory and incidental killing. Our findings reinforce the potential for IGK-mediated cascades in species-rich assemblages and community-wide suppressive effects of large carnivores.


Assuntos
Carnívoros , Ecossistema , Agressão , Animais , Carnívoros/fisiologia , Ecologia , Comportamento Predatório/fisiologia
9.
Knee ; 33: 334-341, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34753025

RESUMO

BACKGROUND: Anterior knee pain is an important complication after total knee arthroplasty (TKA). One possible contributor is the elevation of the joint line, known as pseudo-patella baja (PPB). Limited research has been conducted regarding this condition impacting TKA management. This study aims to evaluate the incidence, identify possible related factors and assess PPB clinical repercussions. METHODS: A total of 813 consecutive TKAs were retrospectively reviewed. Patients were submitted to the same surgical procedure and information regarding TKA characteristics was collected. Lateral postoperative knee radiographs were analyzed using the modified Insall-Salvati Ratio and the Blackburne-Peel Index. A clinical evaluation was conducted on 112 knees where the Oxford Knee and Kujala Scores were applied. Range of motion was evaluated, and knee pain was assessed using the numeric pain rating scale, in addition to analgesic consumption. RESULTS: A cohort of 612 knees was analyzed, of which 64 knees developed PPB (10.5% incidence). Statistically significant differences were found for advance components sizes (femoral P = 0.026 and tibial P < 0.001), polyethylene thickness (P < 0.001) and patients' height (P = 0.022) with smaller implant sizes, greater insert thicknesses and lower height showing an association with PPB. The PPB group had a significantly lower median Kujala score (P = 0.011), higher frequency of flexion contracture and of anterior knee pain (P = 0.039). CONCLUSION: PPB has a clinical relevance that should not be overlooked. Its prevention through the recreation of the natural position of the joint line and correct choice of implant sizes and polyethylene thickness is of major importance and should always be considered.


Assuntos
Artroplastia do Joelho , Artroplastia do Joelho/efeitos adversos , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Patela/cirurgia , Amplitude de Movimento Articular , Estudos Retrospectivos
10.
Animals (Basel) ; 11(9)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34573584

RESUMO

South Africa's decentralized approach to conservation entails that wildlife outside formally protected areas inhabit complex multi-use landscapes, where private wildlife business (ecotourism and/or hunting) co-exist in a human-dominated landscape matrix. Under decentralized conservation, wildlife is perceived to benefit from increased amount of available habitat, however it is crucial to understand how distinct management priorities and associated landscape modifications impact noncharismatic taxa, such as small mammals. We conducted extensive ink-tracking-tunnel surveys to estimate heterogeneity in rodent distribution and investigate the effect of different environmental factors on abundance patterns of two size-based rodent groups (small- and medium-sized species), across three adjacent management contexts in NE KwaZulu-Natal, South Africa: a private ecotourism game reserve, mixed farms and traditional communal areas (consisting of small clusters of houses interspersed with grazing areas and seminatural vegetation). Our hypotheses were formulated regarding the (1) area typology, (2) vegetation structure, (3) ungulate pressure and (4) human disturbance. Using a boosted-regression-tree approach, we found considerable differences between rodent groups' abundance and distribution, and the underlying environmental factors. The mean relative abundance of medium-sized species did not differ across the three management contexts, but small species mean relative abundance was higher in the game reserves, confirming an influence of the area typology on their abundance. Variation in rodent relative abundance was negatively correlated with human disturbance and ungulate presence. Rodent abundance seems to be influenced by environmental gradients that are directly linked to varying management priorities across land uses, meaning that these communities might not benefit uniformly by the increased amount of habitat promoted by the commercial wildlife industry.

11.
BMJ Case Rep ; 14(7)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34253517

RESUMO

Cytomegalovirus (CMV) infection is one of the preeminent congenital viral infections, and despite its potential morbidity, uncertainty about its physiopathology, prevention and treatment remains until now. We report a case of a dichorionic and diamniotic twin pregnancy in which only one of the fetus had signs of being affected. The first twin had prenatal diagnosis of intrauterine growth restriction and hyperechogenic bowel, attributable to CMV infection, while there was no evidence of infection of the second one. Prenatal treatment was done with maternal administration of valacyclovir and postnatal treatment of the infected newborn with oral valganciclovir with normal neurodevelopment assessment at 12 months corrected age. In this case, maternal CMV infection was not equally transmitted to both fetuses, suggesting that there may be intrinsic fetal and placental factors influencing both transmission and the clinical features of the infection.


Assuntos
Infecções por Citomegalovirus , Complicações Infecciosas na Gravidez , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/tratamento farmacológico , Feminino , Humanos , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Placenta , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/tratamento farmacológico , Gravidez de Gêmeos
12.
Proc Biol Sci ; 288(1946): 20202379, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33715442

RESUMO

Apex predator reintroductions have proliferated across southern Africa, yet their ecological effects and proposed umbrella benefits of associated management lack empirical evaluations. Despite a rich theory on top-down ecosystem regulation via mesopredator suppression, a knowledge gap exists relating to the influence of lions (Panthera leo) over Africa's diverse mesocarnivore (less than 20 kg) communities. We investigate how geographical variation in mesocarnivore community richness and occupancy across South African reserves is associated with the presence of lions. An interesting duality emerged: lion reserves held more mesocarnivore-rich communities, yet mesocarnivore occupancy rates and evenness-weighted diversity were lower in the presence of lions. Human population density in the reserve surroundings had a similarly ubiquitous negative effect on mesocarnivore occupancy. The positive association between species richness and lion presence corroborated the umbrella species concept but translated into small differences in community size. Distributional contractions of mesocarnivore species within lion reserves, and potentially corresponding numerical reductions, suggest within-community mesopredator suppression by lions, probably as a result of lethal encounters and responses to a landscape of fear. Our findings offer empirical support for the theoretical understanding of processes underpinning carnivore community assembly and are of conservation relevance under current large-predator orientated management and conservation paradigms.


Assuntos
Carnívoros , Leões , África , Animais , Ecossistema , Geografia , Humanos
13.
Chemosensors (Basel) ; 9(8): 201, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35855953

RESUMO

Ionogel are versatile materials, as they present the electrical properties of ionic liquids and also dimensional stability, since they are trapped in a solid matrix, allowing application in electronic devices such as gas sensors and electronic noses. In this work, ionogels were designed to act as a sensitive layer for the detection of volatiles in a custom-made electronic nose. Ionogels composed of gelatin and a single imidazolium ionic liquid were doped with bare and functionalized iron oxide nanoparticles, producing ionogels with adjustable target selectivity. After exposing an array of four ionogels to 12 distinct volatile organic compounds, the collected signals were analyzed by principal component analysis (PCA) and by several supervised classification methods, in order to assess the ability of the electronic nose to distinguish different volatiles, which showed accuracy above 98%.

14.
Sci Rep ; 10(1): 6651, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313036

RESUMO

The patterns of species co-occurrence have long served as a primary approach to explore concepts of interspecific interaction. However, the interpretation of such patterns is difficult as they can result from several complex ecological processes, in a scale-dependent manner. Here, we aim to investigate the co-occurrence pattern between European rabbit and wild boar in an estate in Central Portugal, using two-species occupancy modelling. With this framework, we tested species interaction for occupancy and detection, but also the interdependencies between both parameters. According to our results, the wild boar and European rabbit occurred independently in the study area. However, model averaging of the detection parameters revealed a potential positive effect of wild boar's presence on rabbit's detection probability. Upon further analysis of the parameter interdependencies, our results suggested that failing to account for a positive effect on rabbit's detection could lead to potentially biased interpretations of the co-occurrence pattern. Our study, in spite of preliminary, highlights the need to understand these different pathways of species interaction to avoid erroneous inferences.


Assuntos
Distribuição Animal/fisiologia , Modelos Estatísticos , Coelhos/fisiologia , Sus scrofa/fisiologia , Animais , Ecossistema , Portugal
15.
Technol Cult ; 61(2): 549-558, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33416777

RESUMO

This overview proposes new ways of interrogating assumptions about globally circulating reproductive technologies and modernities. Comparing and contrasting East Asian experiences of childbirth medicalization provides an alternative to Western-centric discourses and models that tend to focus on notions of individual choice. This special section draws on Chinese and Japanese materials from the twentieth century forward to document how the medicalization of childbirth and use of technology alongside shifting moral ideals and public health policies work to co-produce globalized frameworks of distinctly East Asian modernities. We situate women's birthing experiences in the context of larger reproductive assemblages and hierarchies to highlight the flexible, variable, and contingent spatial and temporal moral tensions and social inequalities shaping ongoing processes of childbirth medicalization and modernization.


Assuntos
Parto Obstétrico , Parto , Feminino , Humanos , Medicalização , Gravidez , Reprodução , Técnicas Reprodutivas
16.
Technol Cult ; 61(2): 581-616, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33416779

RESUMO

In the last 100 years, new biomedical technologies altered childbirth practices in China on virtually every level. This transformation was significantly accelerated after the launch of the Birth Planning Policy in 1979. At the turn of the millennium, the government enforced a policy of mandatory hospital births to bring the country closer to United Nations' Millennium Development Goals in terms of maternal and infant health, but these reforms were accompanied by a dramatic increase in cesarean rates. Drawing on oral history materials collected in a rural community in Guangdong province, this article shows how China's cesarean surge gave rise to complex generational frictions in women's techno-moral understandings of what should be the right way to give birth. These generational frictions show that the history of childbirth medicalization is not just a history of changing institutions, policies and technologies; it is also a history of changing technological selves and moral ideals.


Assuntos
Medicalização , População Rural , Adaptação Psicológica , China , Feminino , Hospitais , Humanos , Lactente , Princípios Morais , Gravidez
17.
Emerg Radiol ; 26(5): 549-556, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31209592

RESUMO

To perform a systematic review (SR) and meta-analysis to determine the diagnostic test accuracy (DTA) of Multi-Detector Computed Tomography (MDCT) for detecting proximal femoral (hip) fragility fractures in patients with a negative initial radiograph. MEDLINE and EMBASE were searched to identify relevant studies published between January 2000 and May 2018. Articles underwent title and abstract screening followed by full-text screening. Study inclusion criteria are patients with suspected hip fracture, negative initial radiograph, MDCT as the index test, magnetic resonance imaging (MRI) or clinical follow-up as the reference standard, and DTA measure as the outcome. Demographic, methodologic, and study outcome data were extracted. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. DTA metrics were pooled using bivariate random-effects meta-analysis. From an initial 1385 studies, four studies reporting on 418 patients (174 with hip fractures) were included. Pooled summary statistics included the following: sensitivity (87%; 95% confidence interval [CI] 79-93), specificity (98%; 95% CI 95-99), and the area under the summary receiver operating characteristic (ROC) curve (0.972). MDCT has a high specificity for detecting hip fragility fractures, comparable to MRI, but a lower sensitivity. Local institutional factors may play a role in whether a patient receives MDCT or MRI, as imaging should not be delayed. If there is ongoing concern for fracture in a patient with a negative MDCT, MRI should be performed. Cautious interpretation of the results is warranted given the risk of bias and small sample size.


Assuntos
Fraturas do Quadril/diagnóstico por imagem , Tomografia Computadorizada Multidetectores , Diagnóstico Diferencial , Humanos , Sensibilidade e Especificidade
18.
PLoS One ; 14(1): e0210661, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30653547

RESUMO

Across the Mediterranean, conservation programmes often operate concomitantly with hunting interests within game-lands. Carnivore guilds lie at the interface between contrasting management goals, being simultaneously fundamental components of ecosystems and targets of predator control to reduce predation on game species. Here, we evaluate the composition and spatial structure of a mesocarnivore community in a protected area of Southeast Portugal, with high economic investment in conservation and significant hunting activity. Between June and August 2015, we deployed 77 camera-traps across a ~80 km2 area. We report on interspecific disparities in mesocarnivore occupancy and associated environmental determinants. Contrasting occupancy states suggest an unbalanced community, biased towards the widespread occurrence of the red fox Vulpes vulpes ([Formula: see text]) compared to other species (stone marten Martes foina, European badger Meles meles, Egyptian mongoose Herpestes ichneumon, common genet Genetta genetta, and Eurasian otter Lutra lutra) exhibiting spatially-restricted occupancy patterns ([Formula: see text]). The feral cat Felis silvestris catus was the exception ([Formula: see text]) and, together with the stone marten, exhibited a positive association with human settlements. These findings are consistent with theoretical predictions on how mesocarnivore communities are shaped by the effects of non-selective predator control, paradoxically favouring species with higher population growth rates and dispersal abilities, such as the red fox. Our results reinforce the need to understand the role of predator control as a community structuring agent with potential unintended effects, while exposing issues hindering such attempts, namely non-selective illegal killing or biased/concealed information on legal control measures.


Assuntos
Ecossistema , Animais , Animais Selvagens , Carnívoros , Gatos , Raposas , Herpestidae , Lontras
19.
ISOEN 2019 (2019) ; 2019: 1-3, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-35939279

RESUMO

The materials described in this work result from the self-assembly of liquid crystals and ionic liquids into droplets, stabilized within a biopolymeric matrix. These systems are extremely versatile gels, in terms of composition, and offer potential for fine tuning of both structure and function, as each individual component can be varied. Here, the characterization and application of these gels as sensing thin films in gas sensor devices is presented. The unique supramolecular structure of the gels is explored for molecular recognition of volatile organic compounds (VOCs) by employing gels with distinct formulations to yield combinatorial optical and electrical responses used in the distinction and identification of VOCs.

20.
Mater Today Bio ; 1: 100002, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32159137

RESUMO

Artificial olfaction is a fast-growing field aiming to mimic natural olfactory systems. Olfactory systems rely on a first step of molecular recognition in which volatile organic compounds (VOCs) bind to an array of specialized olfactory proteins. This results in electrical signals transduced to the brain where pattern recognition is performed. An efficient approach in artificial olfaction combines gas-sensitive materials with dedicated signal processing and classification tools. In this work, films of gelatin hybrid gels with a single composition that change their optical properties upon binding to VOCs were studied as gas-sensing materials in a custom-built electronic nose. The effect of films thickness was studied by acquiring signals from gelatin hybrid gel films with thicknesses between 15 and 90 µm when exposed to 11 distinct VOCs. Several features were extracted from the signals obtained and then used to implement a dedicated automatic classifier based on support vector machines for data processing. As an optical signature could be associated to each VOC, the developed algorithms classified 11 distinct VOCs with high accuracy and precision (higher than 98%), in particular when using optical signals from a single film composition with 30 µm thickness. This shows an unprecedented example of soft matter in artificial olfaction, in which a single gelatin hybrid gel, and not an array of sensing materials, can provide enough information to accurately classify VOCs with small structural and functional differences.

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