Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 164
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Conscious Cogn ; 118: 103633, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38199190

RESUMO

We assessed whether self-related automatic and others-related controlled processes are modulated by chronotype and time-of-day. Here, a shape-label matching task composed of three geometrical shapes arbitrarily associated with you, friend, and stranger was used. Twenty Morning-types, and twenty Evening-types performed the task at the optimal and non-optimal times of day (i.e., 8 AM, or 8:30 PM). Morning-types did not exhibit noticeable synchrony effects, thus proving the better adaptation of these participants to non-optimal moments of the day as compared to Evening-types. Contrary to our predictions regarding the absence of automatic-processing modulation and the presence of controlled-processing influences by time-of-day, we found an influence on self-related but not others-related processing only in Evening-type participants. Although brain structures are not directly tackled, we argue that such modulation may be due to the dependence of the activation of the ventromedial prefrontal cortex (VMPFC), an essential component of the self-attention network on circadian rhythms.


Assuntos
Cronotipo , Ritmo Circadiano , Humanos , Fatores de Tempo , Ritmo Circadiano/fisiologia , Encéfalo , Córtex Pré-Frontal , Sono/fisiologia , Inquéritos e Questionários
2.
Conscious Cogn ; 117: 103607, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38000192

RESUMO

The self-prioritization effect (SPE) refers to the advantage in processing stimuli associated with oneself. Here, we addressed the SPE in an attentional blink (AB) task. In Experiment 1, shapes associated to you, friend, or stranger served as T1, and letter X as T2. The AB effect was larger for you than the other label conditions, and larger for friend condition than for stranger condition. We suggest that self-associated shape increased its perceptual salience, producing greater attentional capture. In Experiment 2 participants trained with a shape-label matching task to increase familiarity with the shape-label associations before performing the AB task. The difference between friend and stranger conditions disappeared, suggesting that the difference between the two conditions observed in Experiment 1 was mainly due to differences in familiarity or frequency of use. Importantly, the advantage of you over friend and stranger conditions remained, suggesting that the SPE is a genuine effect.


Assuntos
Intermitência na Atenção Visual , Humanos , Reconhecimento Psicológico
3.
J Exp Zool B Mol Dev Evol ; 338(1-2): 119-128, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33382212

RESUMO

The adult ankle of early reptiles had five distal tarsal (dt) bones, but in Dinosauria, these were reduced to only two: dt3 and dt4, articulated to metatarsals (mt) mt3 and mt4. Birds have a single distal tarsal ossification center that fuses to the proximal metatarsals to form a new adult skeletal structure: the composite tarsometatarsus. This ossification center develops within a single large embryonic cartilage, but it is unclear if this cartilage results from fusion of earlier cartilages. We studied embryos in species from four different bird orders, an alligatorid, and an iguanid. In all embryos, cartilages dt2, dt3, and dt4 are formed. In the alligatorid and the iguanid, dt2 failed to ossify: only dt3 and dt4 develop into adult bones. In birds, dt2, dt3, and dt4 fuse to form the large distal tarsal cartilage; the ossification center then develops above mt3, in cartilage presumably derived from dt3. During the entire dinosaur-bird transition, a dt2 embryonic cartilage was always formed, as inferred from the embryology of extant birds and crocodilians. We propose that in the evolution of the avian ankle, fusion of cartilages dt3 and dt2 allowed ossification from dt3 to progress into dt2, which began to contribute bone medially, while fusion of dt3 to dt4 enabled the evolutionary loss of the dt4 ossification center. As a result, a single ossification center expands into a plate-like unit covering the proximal ends of the metatarsals, that is key to the development of an integrated tarsometatarsus.


Assuntos
Tornozelo , Evolução Biológica , Animais , Tornozelo/anatomia & histologia , Aves/anatomia & histologia , Dinossauros/anatomia & histologia , Ossos do Metatarso
4.
Psychol Res ; 85(1): 238-245, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31385031

RESUMO

In categorization tasks, two memory systems may be involved in the learning of categories: one explicit and rule-based system and another implicit and procedure-based system. Learning of rule-based categories relies on some form of explicit reasoning, whereas procedural memory underlies information-integration category-learning tasks, in which performance is maximized only if information of two (or more) dimensions is integrated. The present study aimed at investigating the role of how feedback is administered, whether differential or non-differential, in procedural learning. An information-integration category-learning task was designed, where the to-be-categorized stimuli differed in two dimensions. Participants were randomly assigned to two groups: one group received the reinforcers for correct categorizations differentially, one for each category (the differential outcomes procedure, DOP), and the other group received the reinforcers randomly (the non-differential outcomes procedure, NOP). The participants of the DOP group showed better procedural learning in the categorization task, compared to the NOP group. Moreover, the analysis of learning strategies revealed that more participants developed more optimal strategies in the DOP group than in the NOP group. These results extend the benefits of the differential outcomes-based feedback to non-declarative memory tasks and help better understand the role of feedback in procedural learning.


Assuntos
Retroalimentação , Memória , Adulto , Compreensão , Feminino , Humanos , Aprendizagem , Masculino , Resolução de Problemas , Espanha , Adulto Jovem
5.
Molecules ; 26(16)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34443666

RESUMO

The assertion made by Wu et al. that aromaticity may have considerable implications for molecular design motivated us to use nucleus-independent chemical shifts (NICS) as an aromaticity criterion to evaluate the antifungal activity of two series of indol-4-ones. A linear regression analysis of NICS and antifungal activity showed that both tested variables were significantly related (p < 0.05); when aromaticity increased, the antifungal activity decreased for series I and increased for series II. To verify the validity of the obtained equations, a new set of 44 benzofuran-4-ones was designed by replacing the nitrogen atom of the five-membered ring with oxygen in indol-4-ones. The NICS(0) and NICS(1) of benzofuran-4-ones were calculated and used to predict their biological activities using the previous equations. A set of 10 benzofuran-4-ones was synthesized and tested in eight human pathogenic fungi, showing the validity of the equations. The minimum inhibitory concentration (MIC) in yeasts was 31.25 µg·mL-1 for Candida glabrata, Candida krusei and Candida guilliermondii with compounds 15-32, 15-15 and 15-1. The MIC for filamentous fungi was 1.95 µg·mL-1 for Aspergillus niger for compounds 15-1, 15-33 and 15-34. The results obtained support the use of NICS in the molecular design of compounds with antifungal activity.


Assuntos
Antifúngicos/farmacologia , Benzofuranos/farmacologia , Fungos/efeitos dos fármacos , Antifúngicos/química , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/patogenicidade , Benzofuranos/química , Candida/efeitos dos fármacos , Candida/patogenicidade , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pichia/efeitos dos fármacos , Pichia/patogenicidade , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/farmacologia
6.
Molecules ; 26(10)2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-34065875

RESUMO

The Annonaceae fruits weevil (Optatus palmaris) causes high losses to the soursop production in Mexico. Damage occurs when larvae and adults feed on the fruits; however, there is limited research about control strategies against this pest. However, pheromones provide a high potential management scheme for this curculio. Thus, this research characterized the behavior and volatile production of O. palmaris in response to their feeding habits. Olfactometry assays established preference by weevils to volatiles produced by feeding males and soursop. The behavior observed suggests the presence of an aggregation pheromone and a kairomone. Subsequently, insect volatiles sampled by solid-phase microextraction and dynamic headspace detected a unique compound on feeding males increased especially when feeding. Feeding-starvation experiments showed an averaged fifteen-fold increase in the concentration of a monoterpenoid on males feeding on soursop, and a decrease of the release of this compound males stop feeding. GC-MS analysis of volatiles identified this compound as α-terpineol. Further olfactometry assays using α-terpineol and soursop, demonstrated that this combination is double attractive to Annonaceae weevils than only soursop volatiles. The results showed a complementation effect between α-terpineol and soursop volatiles. Thus, α-terpineol is the aggregation pheromone of O. palmaris, and its concentration is enhanced by host-plant volatiles.


Assuntos
Besouros/metabolismo , Monoterpenos Cicloexânicos/análise , Monoterpenos Cicloexânicos/metabolismo , Feromônios/análise , Feromônios/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Animais , Annona/metabolismo , Annonaceae/metabolismo , Monoterpenos Cicloexânicos/química , Comportamento Alimentar , Cromatografia Gasosa-Espectrometria de Massas , Comportamento de Busca por Hospedeiro , Larva/metabolismo , Masculino , México , Monoterpenos/metabolismo , Olfatometria , Feromônios/química , Transdução de Sinais , Microextração em Fase Sólida , Inanição/metabolismo , Compostos Orgânicos Voláteis/química
7.
Arch Microbiol ; 202(3): 579-589, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31741014

RESUMO

Azotobacter vineladii is a Gram-negative bacterium that produces alginate and poly-hydroxybutyrate (PHB), two polymers of biotechnological interest. This bacterium has the ability to form desiccation-resistant cysts. In the cyst the membrane phospholipids are replaced with a family of phenolic lipids called alkylresorcinols (ARs). The alginate, PHB, and ARs are controlled by the GacS/A two-component system and the small regulatory RNA (sRNA) RsmZ1, belonging to the Rsm (Csr) regulatory system. The Rsm (Csr) systems usually possess two or more sRNAs, in this regard A. vinelandii is the bacterium with the highest number of rsm-sRNAs. Originally, the presence of two sRNAs of the RsmY family (RsmY1 and RsmY2) was reported, but in a subsequent work it was suggested that they conformed to a single sRNA. In this work we provide genetic evidence confirming that rsmY1 and rsmY2 constitute a single gene. Also, it was established that rsmY mutation decreased alginate and ARs production, but did not affect the PHB synthesis. Transcriptional studies showed that rsmY has its higher expression during the stationary growth phase, and in the absence of RsmZ1, rsmY increases its transcription. Interestingly, rsmY expression was influenced by the carbon source, but its expression did not correlate with alginate production.


Assuntos
Alginatos/metabolismo , Azotobacter vinelandii/metabolismo , RNA Bacteriano/metabolismo , Resorcinóis/metabolismo , Azotobacter vinelandii/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Hidroxibutiratos/metabolismo , Mutação , RNA Bacteriano/genética
8.
Dev Sci ; 22(2): e12754, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30248216

RESUMO

The current study examines the relationship between 18-month-old toddlers' vocabulary size and their ability to inhibit attention to no-longer relevant information using the backward semantic inhibition paradigm. When adults switch attention from one semantic category to another, the former and no-longer-relevant semantic category becomes inhibited, and subsequent attention to an item that belongs to the inhibited semantic category is impaired. Here we demonstrate that 18-month-olds can inhibit attention to no-longer relevant semantic categories, but only if they have a relatively large vocabulary. These findings suggest that an increased number of items (word knowledge) in the toddler lexical-semantic system during the "vocabulary spurt" at 18-months may be an important driving force behind the emergence of a semantic inhibitory mechanism. Possessing more words in the mental lexicon likely results in the formation of inhibitory links between words, which allow toddlers to select and deselect words and concepts more efficiently. Our findings highlight the role of vocabulary growth in the development of inhibitory processes in the emerging lexical-semantic system.


Assuntos
Inibição Psicológica , Semântica , Vocabulário , Adulto , Atenção/fisiologia , Pré-Escolar , Feminino , Humanos , Lactente , Conhecimento , Masculino , Adulto Jovem
9.
Sensors (Basel) ; 19(12)2019 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-31234599

RESUMO

The functional validity of the signal obtained with low-cost electroencephalography (EEG) devices is still under debate. Here, we have conducted an in-depth comparison of the EEG-recordings obtained with a medical-grade golden-cup electrodes ambulatory device, the SOMNOwatch + EEG-6, vs those obtained with a consumer-grade, single dry electrode low-cost device, the NeuroSky MindWave, one of the most affordable devices currently available. We recorded EEG signals at Fp1 using the two different devices simultaneously on 21 participants who underwent two experimental phases: a 12-minute resting state task (alternating two cycles of closed/open eyes periods), followed by 60-minute virtual-driving task. We evaluated the EEG recording quality by comparing the similarity between the temporal data series, their spectra, their signal-to-noise ratio, the reliability of EEG measurements (comparing the closed eyes periods), as well as their blink detection rate. We found substantial agreement between signals: whereas, qualitatively, the NeuroSky MindWave presented higher levels of noise and a biphasic shape of blinks, the similarity metric indicated that signals from both recording devices were significantly correlated. While the NeuroSky MindWave was less reliable, both devices had a similar blink detection rate. Overall, the NeuroSky MindWave is noise-limited, but provides stable recordings even through long periods of time. Furthermore, its data would be of adequate quality compared to that of conventional wet electrode EEG devices, except for a potential calibration error and spectral differences at low frequencies.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia/instrumentação , Adulto , Eletrodos , Eletroencefalografia/economia , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Razão Sinal-Ruído , Adulto Jovem
10.
Chemphyschem ; 18(15): 1971-1976, 2017 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-28556602

RESUMO

The hydrogen-abstraction/acetylene-addition mechanism has been fundamental to unravelling the synthesis of polycyclic aromatic hydrocarbons (PAHs) detected in combustion flames and carbonaceous meteorites like Orgueil and Murchison. However, the fundamental reaction pathways accounting for the synthesis of complex PAHs, such as the tricyclic anthracene and phenanthrene along with their dihydrogenated counterparts, remain elusive to date. By investigating the hitherto unknown chemistry of the 1-naphthyl radical with 1,3-butadiene, we reveal a facile barrierless synthesis of dihydrophenanthrene adaptable to low temperatures. These aryl-type radical additions to conjugated hydrocarbons via resonantly stabilized free-radical intermediates defy conventional wisdom that PAH growth is predominantly a high-temperature phenomenon and thus may represent an overlooked path to PAHs as complex as coronene and corannulene in cold regions of the interstellar medium like in the Taurus Molecular Cloud.

11.
PLoS Biol ; 12(9): e1001957, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25268520

RESUMO

From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used in palaeontology and developmental biology. We examined embryos of several species and studied chicken embryos in detail through a new technique allowing whole-mount immunofluorescence of the embryonic cartilaginous skeleton. Beyond previous controversy, we establish that the proximal-anterior ossification develops from a composite radiale+intermedium cartilage, consistent with fusion of radiale and intermedium observed in some theropod dinosaurs. Despite previous claims that the development of the distal-anterior ossification does not support the dinosaur-bird link, we found its embryonic precursor shows two distinct regions of both collagen type II and collagen type IX expression, resembling the composite semilunate bone of bird-like dinosaurs (distal carpal 1+distal carpal 2). The distal-posterior ossification develops from a cartilage referred to as "element x," but its position corresponds to distal carpal 3. The proximal-posterior ossification is perhaps most controversial: It is labelled as the ulnare in palaeontology, but we confirm the embryonic ulnare is lost during development. Re-examination of the fossil evidence reveals the ulnare was actually absent in bird-like dinosaurs. We confirm the proximal-posterior bone is a pisiform in terms of embryonic position and its development as a sesamoid associated to a tendon. However, the pisiform is absent in bird-like dinosaurs, which are known from several articulated specimens. The combined data provide compelling evidence of a remarkable evolutionary reversal: A large, ossified pisiform re-evolved in the lineage leading to birds, after a period in which it was either absent, nonossified, or very small, consistently escaping fossil preservation. The bird wrist provides a modern example of how developmental and paleontological data illuminate each other. Based on all available data, we introduce a new nomenclature for bird wrist ossifications.


Assuntos
Evolução Biológica , Carpo Animal/anatomia & histologia , Embrião de Galinha/anatomia & histologia , Dinossauros/anatomia & histologia , Animais , Carpo Animal/metabolismo , Cartilagem/anatomia & histologia , Cartilagem/fisiologia , Embrião de Galinha/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Colágeno Tipo IX/genética , Colágeno Tipo IX/metabolismo , Dinossauros/classificação , Dinossauros/fisiologia , Fósseis , Expressão Gênica , Paleontologia , Tendões/anatomia & histologia , Tendões/fisiologia , Asas de Animais/anatomia & histologia , Asas de Animais/fisiologia
12.
Dev Sci ; 20(1)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28032442

RESUMO

The present research aims to assess literacy acquisition in children becoming bilingual via second language immersion in school. We adopt a cognitive components approach, assessing text-level reading comprehension, a complex literacy skill, as well as underlying cognitive and linguistic components in 144 children aged 7 to 14 (72 immersion bilinguals, 72 controls). Using principal component analysis, a nuanced pattern of results was observed: although emergent bilinguals lag behind their monolingual counterparts on measures of linguistic processing, they showed enhanced performance on a memory and reasoning component. For reading comprehension, no between-group differences were evident, suggesting that selective benefits compensate costs at the level of underlying cognitive components. Overall, the results seem to indicate that literacy skills may be modulated by emerging bilingualism even when no between-group differences are evident at the level of complex skill, and the detection of such differences may depend on the focus and selectivity of the task battery used.


Assuntos
Multilinguismo , Leitura , Adolescente , Estudos de Casos e Controles , Criança , Compreensão , Humanos , Linguística , Memória
13.
Emerg Infect Dis ; 22(9): 1537-44, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27268303

RESUMO

The 2013-2016 outbreak of Ebola virus disease (EVD) in West Africa infected >28,000 people, including >11,000 who died, and disrupted social life in the region. We retrospectively studied clinical signs and symptoms and risk factors for fatal outcome among 31 Ebola virus-positive patients admitted to the Ebola Treatment Center in Moyamba District, Sierra Leone. We found a higher rate of bleeding manifestations than reported elsewhere during the outbreak. Significant predictors for death were shorter time from symptom onset to admission, male sex, high viral load on initial laboratory testing, severe pain, diarrhea, bloody feces, and development of other bleeding manifestations during hospitalization. These risk factors for death could be used to identify patients in need of more intensive medical support. The lack of fever in as many as one third of EVD cases may have implications for temperature-screening practices and case definitions.


Assuntos
Surtos de Doenças , Ebolavirus , Doença pelo Vírus Ebola/diagnóstico , Doença pelo Vírus Ebola/epidemiologia , Avaliação de Sintomas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Ebolavirus/genética , Feminino , Doença pelo Vírus Ebola/história , Doença pelo Vírus Ebola/virologia , História do Século XXI , Humanos , Lactente , Período de Incubação de Doenças Infecciosas , Masculino , Pessoa de Meia-Idade , Mortalidade , Vigilância da População , Estudos Retrospectivos , Serra Leoa/epidemiologia , Carga Viral , Adulto Jovem
14.
Psychol Sci ; 27(10): 1312-1320, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27519530

RESUMO

Attention switching is a crucial ability required in everyday life, from toddlerhood to adulthood. In adults, shifting attention from one word (e.g., dog) to another (e.g., sea) results in backward semantic inhibition, that is, the inhibition of the initial word ( dog). In this study, we used the preferential-looking paradigm to examine whether attention switching is accompanied by backward semantic inhibition in toddlers. We found that 24-month-olds can indeed refocus their attention to a new item by selectively inhibiting attention to the old item. The consequence of backward inhibition is that subsequent attention to a word semantically related to the old item is impaired. These findings have important implications for understanding the underlying mechanism of backward semantic inhibition and the development of lexical-semantic inhibition in early childhood.


Assuntos
Atenção/fisiologia , Inibição Reativa , Semântica , Estimulação Acústica/métodos , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Percepção Visual/fisiologia
15.
BMC Infect Dis ; 16: 308, 2016 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-27334891

RESUMO

BACKGROUND: The last ebola virus disease (EVD) outbreak has been the most important since 1976. EVD cases decreased drastically in Sierra Leone at the beginning of 2015. We aim to determine the clinical findings and evolution of patients admitted to an Ebola treatment center (ETC) during the epidemic's late phase. METHODS: We analyze retrospectively data of patients admitted to the Moyamba ETC (December 2014-March 2015). Patients were classified in EVD or non-EVD patients according to the results of Ebola virus real-time reverse transcription polymerase chain reaction (ZAIRE-RT-PCR). RESULTS: Seventy-five patients were included, 41.3 % were positive for ZAIRE-RT-PCR. More women (68 % vs 28 %, p = 0.001) were EVD-positive. More EVD patients had previous contact with an Ebola patient (74.2 % vs 36.3 %, p < 0.001). At admission, EVD patients were more likely to have fatigue (96.7 %, p < 0.001), diarrhea (67.7 %, p = 0.002), and muscle pain (61.3 %, p = 0.009); but only objective fevers in 35.5 % of EVD patients. The most reliable criteria for diagnosis were: contact with an Ebola patient plus three WHO symptoms (LR + =3.7, 95 % CI = 1.9-7.3), and positive contact (LR + =2.3, 95 % CI = 1.15-4.20). Only 45.2 % of EVD patients developed fevers during stay, but 75 % developed gastrointestinal symptoms. Non-EVD patients had gastrointestinal problems (33 %), respiratory conditions (26.6 %), and others such as malaria, HIV or tuberculosis with a mortality rate of 11.4 %. vs 58 % in EVD group (p < 0.001). CONCLUSIONS: More non-EVD patients were admitted in the outbreak's late phases. The low percentage of initial fever highlights the need to emphasize the epidemiological information. EVD patients presented new symptoms getting worse and requiring closer follow-up. Diagnoses of non-EVD patients were diverse with a remarkable mortality, presenting a challenge for the health system.


Assuntos
Surtos de Doenças , Epidemias , Gastroenteropatias/epidemiologia , Infecções por HIV/epidemiologia , Doença pelo Vírus Ebola/epidemiologia , Encaminhamento e Consulta , Doenças Respiratórias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Diarreia/epidemiologia , Diarreia/etiologia , Ebolavirus/genética , Fadiga/epidemiologia , Fadiga/etiologia , Feminino , Febre/epidemiologia , Febre/etiologia , Gastroenteropatias/complicações , Gastroenteropatias/diagnóstico , Infecções por HIV/complicações , Infecções por HIV/diagnóstico , Doença pelo Vírus Ebola/complicações , Doença pelo Vírus Ebola/diagnóstico , Hospitalização , Humanos , Lactente , Recém-Nascido , Malária/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real/métodos , Doenças Respiratórias/complicações , Doenças Respiratórias/diagnóstico , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serra Leoa/epidemiologia , Adulto Jovem
16.
Brain Cogn ; 108: 73-80, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27566000

RESUMO

Although several recent studies investigated the hemispheric contributions to the attentional networks using the Attention Network Test (ANT), the role of the cerebral hemispheres in modulating the interaction among them remains unclear. In this study, two lateralized versions of this test (LANT) were used to investigate theal effects on the attentional networks under different conflict conditions. One version, the LANTI-A, presented arrows as target and flankers, while the other version, the LANTI-F, had fruits as target and flankers. Data collected from forty-seven participants confirmed well-known results on the efficiency and interactions among the attentional networks. Further, a left visual field advantage was found when a target occurred in an unattended location (e.g. invalid trials), only with the LANTI-F, but not with LANTI-A. The present study adds more evidence to the hemispheric asymmetry of the orienting of attention, and further reveals patterns of interactions between the attentional networks and the visual fields across different conflicting conditions, underlying the dynamic control of attention in complex environments.


Assuntos
Atenção/fisiologia , Função Executiva/fisiologia , Lateralidade Funcional/fisiologia , Rede Nervosa/fisiologia , Campos Visuais/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
17.
Biochim Biophys Acta ; 1844(9): 1427-36, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24792386

RESUMO

The glutathione S-transferase from Plasmodium falciparum presents distinct features which are absent from mammalian GST isoenzyme counterparts. Most apparent among these are the ability to tetramerize and the presence of a flexible loop. The loop, situated between the 113-119 residues, has been reported necessary for the tetramerization process. In this article, we report that a residue outside of this loop, Asn112, is a key to the process - to the point where the single Asn112Leu mutation prevents tetramerization altogether. We propose that a structural pattern involving the interaction of the Asn112 and Lys117 residues from two neighboring subunits plays a role in keeping the tetramer structure stable. We also report that, for the tetramerization of the wild-type PfGST to occur, phosphate or pyrophosphate anions must be present. In other words, tetramerization is a phosphate- or pyrophosphate-induced process. Furthermore, the presence of magnesium reinforces this induction. We present experimental evidence for these claims as well as a preliminary calorimetric and kinetic study of the dimeric Asn112Leu PfGST mutant. We also propose a putative binding site for phosphate or pyrophosphate anions through a comparative structural analysis of PfGST and pyrophosphatases from several organisms. Our results highlight the differences between PfGST and the human isoenzymes, which make the parasite enzyme a suitable antimalarial target.


Assuntos
Asparagina/química , Difosfatos/química , Glutationa Transferase/química , Fosfatos/química , Plasmodium falciparum/química , Subunidades Proteicas/química , Proteínas de Protozoários/química , Asparagina/metabolismo , Cátions Bivalentes , Difosfatos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Humanos , Cinética , Magnésio/química , Magnésio/metabolismo , Modelos Moleculares , Mutação , Fosfatos/metabolismo , Plasmodium falciparum/enzimologia , Multimerização Proteica , Estabilidade Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade da Espécie , Termodinâmica
18.
Front Zool ; 11(1): 33, 2014 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-24725625

RESUMO

BACKGROUND: The homology of the digits in the bird wing is a high-profile controversy in developmental and evolutionary biology. The embryonic position of the digits cartilages with respect to the primary axis (ulnare and ulna) corresponds to 2, 3, 4, but comparative-evolutionary morphology supports 1, 2, 3. A homeotic frameshift of digit identity in evolution could explain how cells in embryonic positions 2, 3, 4 began developing morphologies 1, 2, 3. Another alternative is that no re-patterning of cell fates occurred, and the primary axis shifted its position by some other mechanism. In the wing, only the anterior digit lacks expression of HoxD10 and HoxD12, resembling digit 1 of other limbs, as predicted by 1, 2, 3. However, upon loss of digit 1 in evolution, the most anterior digit 2 could have lost their expression, deceitfully resembling a digit 1. To test this notion, we observed HoxD10 and HoxD12 in a limb where digit 2 is the most anterior digit: The rabbit foot. We also explored whether early inhibition of Shh signalling in the embryonic wing bud induces an experimental homeotic frameshift, or an experimental axis shift. We tested these hypotheses using DiI injections to study the fate of cells in these experimental wings. RESULTS: We found strong transcription of HoxD10 and HoxD12 was present in the most anterior digit 2 of the rabbit foot. Thus, we found no evidence to question the use of HoxD expression as support for 1, 2, 3. When Shh signalling in early wing buds is inhibited, our fate maps demonstrate that an experimental homeotic frameshift is induced. CONCLUSION: Along with comparative morphology, HoxD expression provides strong support for 1, 2, 3 identity of wing digits. As an explanation for the offset 2, 3, 4 embryological position, the homeotic frameshift hypothesis is consistent with known mechanisms of limb development, and further proven to be experimentally possible. In contrast, the underlying mechanisms and experimental plausibility of an axis shift remain unclear.

19.
Langmuir ; 30(1): 234-42, 2014 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-24313322

RESUMO

Three novel gold nanoparticles containing multiple long, flexible linkers decorated with lactose, ß-cyclodextrin, and both simultaneously have been prepared. The interaction of such nanoparticles with ß-d-galactose-recognizing lectins peanut agglutinin (PNA) and human galectin-3 (Gal-3) was demonstrated by UV-vis studies. Gal-3 is well-known to be overexpressed in several human tumors and can act as a biorecognizable target. This technique also allowed us to estimate their loading capability toward the anticancer drug methotrexate (MTX). Both results make these glyconanoparticles potential site-specific delivery systems for anticancer drugs.


Assuntos
Sistemas de Liberação de Medicamentos , Ouro/química , Nanopartículas Metálicas/química , beta-Ciclodextrinas/química , Aglutininas/química , Proteínas Sanguíneas , Galactose/química , Galectina 3/química , Galectinas , Humanos , Modelos Moleculares
20.
Exp Brain Res ; 232(10): 3147-57, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24913142

RESUMO

Short-term sleep deprivation, or extended wakefulness, adversely affects cognitive functions and behavior. However, scarce research has addressed the effects of sleep deprivation (SD) on emotional processing. In this study, we investigated the impact of reduced vigilance due to moderate sleep deprivation on the ability to recognize emotional expressions of faces and emotional content of words. Participants remained awake for 24 h and performed the tasks in two sessions, one in which they were not affected by sleep loss (baseline; BSL), and other affected by SD, according to a counterbalanced sequence. Tasks were carried out twice at 10:00 and 4:00 am, or at 12:00 and 6:00 am. In both tasks, participants had to respond to the emotional valence of the target stimulus: negative, positive, or neutral. The results showed that in the word task, sleep deprivation impaired recognition irrespective of the emotional valence of words. However, sleep deprivation impaired recognition of emotional face expressions mainly when they showed a neutral expression. Emotional face expressions were less affected by the sleep loss, but positive faces were more resistant than negative faces to the detrimental effect of sleep deprivation. The differential effects of sleep deprivation on recognition of the different emotional stimuli are indicative of emotional facial expressions being stronger emotional stimuli than emotional laden words. This dissociation may be attributed to the more automatic sensory encoding of emotional facial content.


Assuntos
Atenção/fisiologia , Cognição/fisiologia , Emoções/fisiologia , Expressão Facial , Reconhecimento Visual de Modelos/fisiologia , Privação do Sono/psicologia , Adolescente , Adulto , Face/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Vigília/fisiologia , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA