Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
Appl Microbiol Biotechnol ; 105(24): 9125-9136, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34811605

RESUMO

Product retention in hollow fibers is a common issue in ATF-based cell culture system. In this study, the effects of four major process factors on product (therapeutic antibody/recombinant protein) retention were investigated using Chinese hamster ovary cell. Hollow fibers made of polysulfone presented a product retention rate from 15% ± 8 to 43% ± 18% higher than those made of polyether sulfone varying with specific processes. Higher harvest flowrate and ATF exchange rate increased product retention by 13% ± 10% and up to 31% ± 13%, respectively. Hollow fibers with larger pore sizes (0.65 µm) appeared to have increased product retention by 38% ± 7% compared with smaller ones (0.2 µm) in this study. Further investigation revealed that the effects of pore size on retention could be correlated to the particle size distribution in the cell culture broth. A hollow fiber with a larger pore size (>0.5 µm) may reduce protein retention when small particles (approximately 0.01-0.2 µm in diameter) are dominant in the culture. However, if majority of the particles are larger than 0.2 µm in diameter, hollow fiber with smaller pore sizes (0.2 µm) could be a solution to reducing product retention. Alternatively, process optimization may modulate particle size distribution towards reduced production retention with selected ATF hollow fibers. This study for the first time highlights the importance of matching proper pore sizes of hollow fibers with the cell culture particles distribution and offers methods to reducing product retention and ATF column clogging in perfusion cell cultures. KEY POINTS: The material of ATF column could impact product retention during perfusion culture. Higher harvest flowrate and ATF exchange rate increased product retention. Matching culture particle size and ATF pore size is critical for retention modulation.

2.
Aust Crit Care ; 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34654611

RESUMO

BACKGROUND: Coronavirus disease-2019 (COVID-19) has effected major changes to healthcare delivery within acute care settings. Rapid response calls (RRCs) in healthcare organisations have been effective at identifying and urgently managing acute clinical deterioration. Code-95 RRC were introduced to prewarn healthcare workers (HCWs) attending to patients suspected or confirmed with COVID-19 infection. AIMS: The primary aim of the study was to identify the personal impact of the COVID-19 pandemic on HCWs involved in attending Code-95 RRC. We sought to evaluate their perception of risks and effects on wellbeing and identify potential opportunities for improvement at organisational levels. METHODS: We undertook a detailed survey on HCWs attending Code-95 RRCs, including questions that sought to understand the impact of the pandemic as well as their perception of infection risk and emotional wellbeing. This was a substudy of the prospective cross-sectional single-centre survey of HCWs that was conducted over a 3-week period at Frankston Hospital, Victoria, Australia. We adopted a quantitative content analysis approach for free-text responses in this secondary analysis. RESULTS: Four hundred two free-text comments were received from 297 respondents and were analysed. More than two-thirds (68%, 223/297) were female. Of all comments, 39% (155/402) were related to organisational issues including communication, confusion due to constantly changing infection control policies, and insufficient training. Thirty-three percent of comments (133/402) raised issues regarding the adequacy of personal protective equipment. Anxiety was reported in 25% of comments (101/402) with concerns predominantly relating to emotional stress and fatigue, risks of virus exposure and transmitting the infection to others, and COVID-19 precautions impairing care delivery. CONCLUSION(S): Our study raises important issues that have relevance for all healthcare organisations in the management of patients with COVID-19. These include the importance of improving communication, especially when infection control policies are revised, optimising training, maintaining adequate personal protective equipment, and HCW support. Early recognition and management of these issues are crucial to maintain optimal healthcare delivery.

3.
J Formos Med Assoc ; 120 Suppl 1: S26-S37, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34083090

RESUMO

BACKGROUND: As Coronavirus disease 2019 (COVID-19) pandemic led to the unprecedent large-scale repeated surges of epidemics worldwide since the end of 2019, data-driven analysis to look into the duration and case load of each episode of outbreak worldwide has been motivated. METHODS: Using open data repository with daily infected, recovered and death cases in the period between March 2020 and April 2021, a descriptive analysis was performed. The susceptible-exposed-infected-recovery model was used to estimate the effective productive number (Rt). The duration taken from Rt > 1 to Rt < 1 and case load were first modelled by using the compound Poisson method. Machine learning analysis using the K-means clustering method was further adopted to classify patterns of community-acquired outbreaks worldwide. RESULTS: The global estimated Rt declined after the first surge of COVID-19 pandemic but there were still two major surges of epidemics occurring in September 2020 and March 2021, respectively, and numerous episodes due to various extents of Nonpharmaceutical Interventions (NPIs). Unsupervised machine learning identified five patterns as "controlled epidemic", "mutant propagated epidemic", "propagated epidemic", "persistent epidemic" and "long persistent epidemic" with the corresponding duration and the logarithm of case load from the lowest (18.6 ± 11.7; 3.4 ± 1.8)) to the highest (258.2 ± 31.9; 11.9 ± 2.4). Countries like Taiwan outside five clusters were classified as no community-acquired outbreak. CONCLUSION: Data-driven models for the new classification of community-acquired outbreaks are useful for global surveillance of uninterrupted COVID-19 pandemic and provide a timely decision support for the distribution of vaccine and the optimal NPIs from global to local community.


Assuntos
COVID-19 , Pandemias , COVID-19/epidemiologia , Infecções Comunitárias Adquiridas/classificação , Surtos de Doenças , Humanos , Aprendizado de Máquina , Modelos Estatísticos , SARS-CoV-2 , Taiwan
4.
J Formos Med Assoc ; 120 Suppl 1: S95-S105, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34108119

RESUMO

BACKGROUND: Vaccine is supposed to be the most effective means to prevent COVID-19 as it may not only save lives but also reduce productivity loss due to resuming pre-pandemic activities. Providing the results of economic evaluation for mass vaccination is of paramount importance for all stakeholders worldwide. METHODS: We developed a Markov decision tree for the economic evaluation of mass vaccination against COVID-19. The effectiveness of reducing outcomes after the administration of three COVID-19 vaccines (BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and AZD1222 (Oxford-AstraZeneca)) were modelled with empirical parameters obtained from literatures. The direct cost of vaccine and COVID-19 related medical cost, the indirect cost of productivity loss due to vaccine jabs and hospitalization, and the productivity loss were accumulated given different vaccination scenarios. We reported the incremental cost-utility ratio and benefit/cost (B/C) ratio of three vaccines compared to no vaccination with a probabilistic approach. RESULTS: Moderna and Pfizer vaccines won the greatest effectiveness among the three vaccines under consideration. After taking both direct and indirect costs into account, all of the three vaccines dominated no vaccination strategy. The results of B/C ratio show that one dollar invested in vaccine would have USD $13, USD $23, and USD $28 in return for Moderna, Pfizer, and AstraZeneca, respectively when health and education loss are considered. The corresponding figures taking value of the statistical life into account were USD $176, USD $300, and USD $443. CONCLUSION: Mass vaccination against COVID-19 with three current available vaccines is cost-saving for gaining more lives and less cost incurred.


Assuntos
COVID-19 , Vacinação em Massa , COVID-19/economia , COVID-19/prevenção & controle , Vacinas contra COVID-19/economia , Análise Custo-Benefício , Humanos , Vacinação em Massa/economia
5.
J Formos Med Assoc ; 120 Suppl 1: S19-S25, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34112588

RESUMO

BACKGROUND: As COVID-19 has become a pandemic emerging infectious disease it is important to examine whether there was a spatiotemporal clustering phenomenon in the globe during the rapid spread after the first outbreak reported from southern China. MATERIALS AND METHODS: The open data on the number of COVID-19 cases reported at daily basis form the globe were used to assess the evolution of outbreaks with international air link on the same latitude and also including Taiwan. The dynamic Susceptible-Infected-Recovered model was used to evaluate continental transmission from December 2019 to March 2020 before the declaration of COVID-19 pandemic with basic reproductive number and effective reproductive number before and after containment measurements. RESULTS: For the initial COVID-19 outbreak in China, the estimated reproductive number was reduced from 2.84 during the overwhelming outbreaks in early January to 0.43 after the strict lockdown policy. It is very surprising to find there were three countries (including South Korea, Iran, and Italy) and the Washington state of the USA on the 38° North Latitude involved with large-scale community-acquired outbreaks since the first imported COVID-19 cases from China. The propagation of continental transmission was augmented from hotspot to hotspot with higher reproductive number immediately before the declaration of pandemic. By contrast, there was not any large community-acquired outbreak in Taiwan. CONCLUSION: The propagated spatiotemporal transmission from China to other hotspots may explain the emerging pandemic that can only be exempted by timely border control and preparedness of containment measurements according to Taiwan experience.


Assuntos
COVID-19 , Pandemias , COVID-19/transmissão , China/epidemiologia , Controle de Doenças Transmissíveis , Infecções Comunitárias Adquiridas/transmissão , Humanos , Irã (Geográfico)/epidemiologia , Itália/epidemiologia , República da Coreia/epidemiologia , SARS-CoV-2 , Taiwan/epidemiologia , Washington/epidemiologia
6.
Front Neurol ; 12: 606673, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34135840

RESUMO

Background: In most countries, large cerebral artery occlusion is identified as the leading cause of disability. In 2015, five large-scale clinical trials confirmed the benefit of intra-arterial thrombectomy. However, thrombectomy is a highly technical and facility-dependent procedure. Primary stroke centers need to transfer patients to comprehensive stroke centers to perform thrombectomy. The time-lapse during interhospital transfer would decrease the chance of the patient's proper recovery. Communication barriers also contribute to this delay. Aims: We used a smartphone application to overcome communication barriers between hospitals. We aimed to shorten the door-to-puncture time of interhospital transfer patients. Methods: We began using a smartphone application, "LINE," to facilitate interhospital communication on May 01, 2018. We carried out retrospective data analyses for all the transfer patients (n = 351), with the primary outcome being the door-to-puncture time in our comprehensive stroke center (China Medical University Hospital). We compared the three periods: May 01 to Dec 31, 2017 (before the use of the smartphone application); May 01 to Dec 31, 2018 (the 1st year of using the smartphone application); and May 01 to Dec 31, 2019 (the 2nd year of using the smartphone application). We also compared the transfer data with non-transfer thrombectomies in the same period. Results: We compared 2017, 2018, and 2019 data. The total number of transfer patients increased over the years: 63, 113, 175, respectively. The mean door-to-puncture time decreased significantly, going from 109, through 102, to 92 min. Meanwhile, the mean door-to-puncture time in non-transfer patients were 140.3, 122.1, and 129.3 min. The main reason of time saving was the change of the way of communication, from point-to-point interhospital communication to hub-to-spoke interhospital communication. Conclusions: We used this smartphone application to enhance interhospital communication, changed from the point-to-point to hub-to-spoke method. It made us overcome the communication barrier and build up interhospital connection, thus shortening the door-to-puncture time. Our experience demonstrated the importance of close communication and teamwork in hyperacute stroke care, especially in interhospital transfer for thrombectomy.

7.
Intern Med J ; 51(4): 494-505, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33890372

RESUMO

BACKGROUND: To allow better allocation of staff and resources, rapid response teams attending to acutely deteriorating or aggressive patients with suspected or confirmed COVID-19 infection were pre-warned with the announcement of 'Code-95' with calls. AIM: To assess healthcare worker (HCW) perspectives on pre-warning rapid response calls (RRC) with 'Code-95' in announcements when attending to deteriorating or aggressive patients with suspected/confirmed COVID-19 infection. METHODS: Design: prospective cross-sectional single-centre survey of HCW over a 3-week period. SETTING: tertiary public hospital. PARTICIPANTS: HCW caring for deteriorating or aggressive patients. MAIN OUTCOME MEASURES: the primary outcome was to assess HCW perspectives in attending Code-95 calls. Secondary outcomes were to identify any differences related to craft group, age, experience or presence of comorbidities. RESULTS: A total of 297 responses was analysed; 86.7% of HCW (n = 257) attending Code-95 calls reported anxiety. Medical staff reported greater anxiety in comparison to nursing staff (93.8% vs 78.5%; P = 0.002). Efferent team reported higher anxiety in contrast to afferent team (92.6% vs 58.8%; P = 0.021). There was no significant difference in perceived anxiety based on age (≤40 vs >40 years of age), years of experience (≤5 vs >5 years), comorbidities or mental illness; 54% reported concerns about adequacy of infection-control policies and personal protective equipment; 45% were worried about inadequate training for responding to Code-95 calls. CONCLUSIONS: Most surveyed HCW supported Code-95 announcements pre-warning them of potential COVID-19 exposure when attending a RRC. However, the majority of HCW reported anxiety when attending these calls. Medical and efferent team HCW perceived greater anxiety compared to nursing and afferent team HCW. The Code-95 system to pre-warn rapid response teams may be a useful addition to protecting HCW from infectious diseases, although broader implementation will require greater resourcing, training and support.


Assuntos
COVID-19 , Adulto , Estudos Transversais , Pessoal de Saúde , Humanos , Percepção , Estudos Prospectivos , SARS-CoV-2
8.
Technol Cancer Res Treat ; 20: 1533033821995277, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33706617

RESUMO

PURPOSE: Approximately 5%-10% of men who receive prostate cancer radiotherapy will suffer from radiation cystitis. Bladder filling before the administration of radiotherapy results in lower radiation exposure to the bladder. BladderScan, an ultrasound-based bladder volume scanner, has the potential to evaluate bladder volume during radiotherapy; thus, a prospective pilot study was initiated. METHODS: Eleven men receiving tomotherapy for localized prostate cancer were enrolled. The validity of BladderScan was evaluated by comparing the measurements from BladderScan with the calculated volume from megavoltage computed tomography (MVCT). With a crossover design to compare different methods in bladder filling, the radiotherapy was divided into 2 sequences. Conventional method: the patient was asked to drink water after voiding urine. The amount of water and the duration of waiting were the same as in the setting of the simulation. BladderScan feedback method: the bladder filling procedure depended on the BladderScan measurements. RESULTS: There were 314 sets of data from 11 patients. The correlation coefficient between VBS and VCT was 0.87, where VBS is the mean volume of 3 measurements by BladderScan and VCT is the bladder volume derived from MVCT. The BladderScan feedback method resulted in a significant larger bladder volume than the conventional method, with a mean difference of 36.9 mL. When the failure was defined as VCT <80% of planned volume, the BladderScan feedback method brought about a relative reduction in the failure rate with an odds ratio of 0.44 and an absolute reduction of 9.1%. CONCLUSION: The accuracy of BladderScan was validated by MVCT in our study. The BladderScan feedback method can help patients fill the bladder adequately, with a larger bladder volume and a lower failure rate.


Assuntos
Neoplasias da Próstata/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Bexiga Urinária/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Gerenciamento Clínico , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Prognóstico , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapia
9.
Biomaterials ; 271: 120762, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33773400

RESUMO

Although traditional 3D scaffolds or biomimetic hydrogels have been used for tissue engineering and regenerative medicine, soft tissue microenvironment usually has a highly anisotropic structure and a dynamically controllable deformation with various biomolecule distribution. In this study, we developed a hierarchical hybrid gelatin methacrylate-microcapsule hydrogel (HGMH) with Neurotrophin-3(NT-3)-loaded PLGA microcapsules to fabricate anisotropic structure with patterned NT-3 distribution (demonstrated as striped and triangular patterns) by dielectrophoresis (DEP). The HGMH provides a dynamic biomimetic sinuate-microwrinkles change with NT-3 spatial gradient and 2-stage time-dependent distribution, which was further simulated using a 3D finite element model. As demonstrated, in comparison with striped-patterned hydrogel, the triangular-patterned HGMH with highly anisotropic array of microcapsules exhibits remarkably spatial NT-3 gradient distributions that can not only guide neural stem cells (NSCs) migration but also facilitate spinal cord injury regeneration. This approach to construct hierarchical 4D hydrogel system via an electromicrofluidic platform demonstrates the potential for building various biomimetic soft scaffolds in vitro tailed to real soft tissues.


Assuntos
Hidrogéis , Regeneração da Medula Espinal , Cápsulas , Engenharia Tecidual , Tecidos Suporte
10.
J Perioper Pract ; 31(10): 391-398, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32894998

RESUMO

PURPOSE: Current guidelines recommend withholding sodium-glucose cotransporter 2 inhibitors perioperatively due to concerns of euglycaemic diabetic ketoacidosis. However, such guidelines are largely based on case reports and small case series, many extrapolated from non-surgical patients. The aim was to investigate whether withholding sodium-glucose cotransporter 2 inhibitors as per current perioperative guidelines was associated with a reduction in serious adverse events, including euglycaemic diabetic ketoacidosis. METHODS: Instances of perioperative management of sodium-glucose cotransporter 2 inhibitors, over a four-year period were classified into two categories: those where sodium-glucose cotransporter 2 inhibitors were withheld as per guidelines and those where sodium-glucose cotransporter 2 inhibitors were administered in the perioperative period. The primary outcome was 'total major perioperative complications': a composite of serious adverse events including euglycaemic diabetic ketoacidosis, diabetic ketoacidosis, acute kidney injury, urosepsis and death. RESULTS: Eighty-two instances in 64 patients were included. Withholding sodium-glucose cotransporter 2 inhibitors was associated with an increased incidence of total major perioperative complications and poorer glycaemic control postoperatively. Multivariable logistic regression analysis revealed that withholding sodium-glucose cotransporter 2 inhibitors perioperatively (OR = 13.15; 95% CI = 1.8-138.9) and preoperative urea (OR 1.85 (95% CI = 1.17-3.43) were independently associated with an increase in total major postoperative complications. CONCLUSION: Withholding sodium-glucose cotransporter 2 inhibitors as per current guidelines was associated with an increase in postoperative complications and reduced glycaemic control.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores do Transportador 2 de Sódio-Glicose , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucose , Humanos , Hipoglicemiantes/efeitos adversos , Estudos Retrospectivos , Sódio , Inibidores do Transportador 2 de Sódio-Glicose/efeitos adversos
11.
Cereb Cortex ; 31(2): 974-992, 2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-32935833

RESUMO

It is generally assumed that the encoding of a single event generates multiple memory representations, which contribute differently to subsequent episodic memory. We used functional magnetic resonance imaging (fMRI) and representational similarity analysis to examine how visual and semantic representations predicted subsequent memory for single item encoding (e.g., seeing an orange). Three levels of visual representations corresponding to early, middle, and late visual processing stages were based on a deep neural network. Three levels of semantic representations were based on normative observed ("is round"), taxonomic ("is a fruit"), and encyclopedic features ("is sweet"). We identified brain regions where each representation type predicted later perceptual memory, conceptual memory, or both (general memory). Participants encoded objects during fMRI, and then completed both a word-based conceptual and picture-based perceptual memory test. Visual representations predicted subsequent perceptual memory in visual cortices, but also facilitated conceptual and general memory in more anterior regions. Semantic representations, in turn, predicted perceptual memory in visual cortex, conceptual memory in the perirhinal and inferior prefrontal cortex, and general memory in the angular gyrus. These results suggest that the contribution of visual and semantic representations to subsequent memory effects depends on a complex interaction between representation, test type, and storage location.

12.
J Cogn Neurosci ; 33(1): 77-88, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32812826

RESUMO

Although a large proportion of the lexicon consists of abstract concepts, little is known about how they are represented by the brain. Here, we investigated how the mind represents relations shared between sets of mental representations that are superficially unrelated, such as car-engine and dog-tongue, but that nonetheless share a more general, abstract relation, such as whole-part. Participants saw a pair of words on each trial and were asked to indicate whether they could think of a relation between them. Importantly, they were not explicitly asked whether different word pairs shared the same relation, as in analogical reasoning tasks. We observed representational similarity for abstract relations in regions in the "conceptual hub" network, even when controlling for semantic relatedness between word pairs. By contrast, we did not observe representational similarity in regions previously implicated in explicit analogical reasoning. A given relation was sometimes repeated across sequential word pairs, allowing us to test for behavioral and neural priming of abstract relations. Indeed, we observed faster RTs and greater representational similarity for primed than unprimed trials, suggesting that mental representations of abstract relations are transiently activated on this incidental analogy task. Finally, we found a significant correlation between behavioral and neural priming across participants. To our knowledge, this is the first study to investigate relational priming using functional neuroimaging and to show that neural representations are strengthened by relational priming. This research shows how abstract concepts can be brought to mind momentarily, even when not required for task performance.


Assuntos
Resolução de Problemas , Semântica , Encéfalo , Formação de Conceito , Humanos , Análise e Desempenho de Tarefas
13.
Curr Biol ; 30(23): 4606-4618.e4, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33007241

RESUMO

Dopamine (DA)-producing neurons are critically involved in the production of motor behaviors in multiple circuits that are conserved from basal vertebrates to mammals. Although there is increasing evidence that DA neurons in the hypothalamus play a locomotor role, their precise contributions to behavior and the circuit mechanisms by which they are achieved remain unclear. Here, we demonstrate that tyrosine-hydroxylase-2-expressing (th2+) DA neurons in the zebrafish hypothalamus fire phasic bursts of activity to acutely promote swimming and modulate audiomotor behaviors on fast timescales. Their anatomy and physiology reveal two distinct functional DA modules within the hypothalamus. The first comprises an interconnected set of cerebrospinal-fluid-contacting DA nuclei surrounding the 3rd ventricle, which lack distal projections outside of the hypothalamus and influence locomotion through unknown means. The second includes neurons in the preoptic nucleus, which send long-range projections to targets throughout the brain, including the mid- and hindbrain, where they activate premotor circuits involved in swimming and sensorimotor integration. These data suggest a broad regulation of motor behavior by DA neurons within multiple hypothalamic nuclei and elucidate a novel functional mechanism for the preoptic DA neurons in the initiation of movement.


Assuntos
Tronco Encefálico/fisiologia , Neurônios Dopaminérgicos/metabolismo , Área Pré-Óptica/fisiologia , Natação/fisiologia , Animais , Tronco Encefálico/citologia , Potencial Evocado Motor/fisiologia , Genes Reporter/genética , Proteínas de Fluorescência Verde/genética , Microscopia Intravital/métodos , Masculino , Microscopia de Fluorescência por Excitação Multifotônica , Modelos Animais , Rede Nervosa/fisiologia , Optogenética , Área Pré-Óptica/citologia , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Gravação em Vídeo , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
J Neurosci ; 40(9): 1920-1930, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-31974208

RESUMO

The declarative memory system allows us to accurately recognize a countless number of items and events, particularly those strengthened by repeated exposure. However, increased familiarity due to repetition can also lead to false recognition of related but new items, particularly when mechanisms supporting fine-grain mnemonic discrimination fail. The hippocampus is thought to be particularly important in separating overlapping cortical inputs during encoding so that similar experiences can be differentiated. In the current study of male and female human subjects, we examine how neural pattern similarity between repeated exemplars of a given concept (e.g., apple) influences true and false memory for target or lure images. Consistent with past work, we found that subsequent true recognition was related to pattern similarity between concept exemplars and the entire encoding set (global encoding similarity), particularly in ventral visual stream. In addition, memory for an individual target exemplar (a specific apple) could be predicted solely by the degree of pattern overlap between the other exemplars (different apple pictures) of that concept (concept-specific encoding similarity). Critically, subsequent false memory for lures was mitigated when high concept-specific similarity in cortical areas was accompanied by differentiated hippocampal representations of the corresponding exemplars. Furthermore, both true and false memory entailed the reinstatement of concept-related information at varying levels of specificity. These results link both true and false memory to a measure of concept strength expressed in the overlap of cortical representations, and importantly, illustrate how the hippocampus serves to separate concurrent cortical overlap in the service of detailed memory.SIGNIFICANCE STATEMENT In some instances, the same processes that help promote memory for a general idea or concept can also hinder more detailed memory judgments, which may involve differentiating between closely related items. The current study shows that increased overlap in cortical representations for conceptually-related pictures is associated with increased recognition of repeated concept pictures. Whether similar lure items were falsely remembered as old further depended on the hippocampus, where the presence of more distinct representations protected against later false memory. This work suggests that the differentiability of brain patterns during perception is related to the differentiability of items in memory, but that fine-grain discrimination depends on the interaction between cortex and hippocampus.


Assuntos
Córtex Cerebral/fisiologia , Hipocampo/fisiologia , Memória/fisiologia , Repressão Psicológica , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Rememoração Mental/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Estimulação Luminosa , Reconhecimento Psicológico , Vias Visuais/fisiologia , Adulto Jovem
15.
Behav Brain Sci ; 42: e302, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31896371

RESUMO

Bastin and colleagues present an integrative model of how recollection- and familiarity-based memories are represented in the brain. While they emphasize the role of attribution mechanisms in shaping memory retrieval, prior work examining implicit memory suggests that memory deficits may be better understood by separating attributional biases from the underlying memory traces.


Assuntos
Rememoração Mental , Reconhecimento Psicológico , Viés , Humanos , Memória , Transtornos da Memória
16.
Nat Neurosci ; 22(9): 1477-1492, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31358991

RESUMO

Animals have evolved specialized neural circuits to defend themselves from pain- and injury-causing stimuli. Using a combination of optical, behavioral and genetic approaches in the larval zebrafish, we describe a novel role for hypothalamic oxytocin (OXT) neurons in the processing of noxious stimuli. In vivo imaging revealed that a large and distributed fraction of zebrafish OXT neurons respond strongly to noxious inputs, including the activation of damage-sensing TRPA1 receptors. OXT population activity reflects the sensorimotor transformation of the noxious stimulus, with some neurons encoding sensory information and others correlating more strongly with large-angle swims. Notably, OXT neuron activation is sufficient to generate this defensive behavior via the recruitment of brainstem premotor targets, whereas ablation of OXT neurons or loss of the peptide attenuates behavioral responses to TRPA1 activation. These data highlight a crucial role for OXT neurons in the generation of appropriate defensive responses to noxious input.


Assuntos
Tronco Encefálico/fisiologia , Vias Neurais/fisiologia , Nociceptividade/fisiologia , Nociceptores/fisiologia , Animais , Tronco Encefálico/citologia , Hipotálamo/citologia , Hipotálamo/fisiologia , Vias Neurais/citologia , Nociceptores/citologia , Ocitocina , Peixe-Zebra
17.
N Z Med J ; 132(1495): 13-22, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31095540

RESUMO

AIM: Prognostication and decisions regarding ineffectiveness of treatment remain challenging for clinicians and are some of the most difficult yet understudied aspects of clinical medicine. We sought to explore what management intensivists would advocate for a patient, for themselves or for a loved one at different points in an evolving hypothetical clinical scenario of a critically ill patient admitted to the intensive care unit (ICU). METHOD: An online survey was constructed and was circulated to fellows of the College of Intensive Care Medicine (CICM) of Australia and New Zealand. Participants were presented with an evolving hypothetical clinical scenario of a patient admitted to ICU following out-of-hospital cardiac arrest (OHCA) at four time-points (day 3,7,14 and 28) during their conceptual ICU stay. RESULTS: One hundred and twenty-six CICM fellows participated. Survey responses revealed significant differences in the proportion of respondents that would advocate for aggressive treatment, conservative management or withdrawal of treatment for themselves compared to patients; for a family member as compared to a patient at several time points. CONCLUSIONS: The management that intensivists would advocate for patients differs from the management that they would advocate for their loved ones and themselves.


Assuntos
Atitude do Pessoal de Saúde , Tomada de Decisão Clínica , Família/psicologia , Médicos , Adulto , Austrália , Cuidados Críticos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Nova Zelândia , Médicos/psicologia , Médicos/estatística & dados numéricos , Inquéritos e Questionários
18.
Eur J Neurosci ; 48(11): 3389-3396, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30290029

RESUMO

Depending on a person's goals, different aspects of stored knowledge are accessed. Decades of behavioral work document the flexible use of knowledge, but little neuroimaging work speaks to these questions. We used representational similarity analysis to investigate whether the relationship between brain activity and semantic structure of statements varied in two tasks hypothesized to differ in the degree to which knowledge is accessed: judging truth (semantic task) and judging oldness (episodic task). During truth judgments, but not old/new recognition judgments, a left-lateralized network previously associated with semantic memory exhibited correlations with semantic structure. At a neural level, people activate knowledge representations in different ways when focused on different goals. The present results demonstrate the potential of multivariate approaches in characterizing knowledge storage and retrieval, as well as the ways that it shapes our understanding and long-term memory.


Assuntos
Mapeamento Encefálico , Objetivos , Conhecimento , Memória/fisiologia , Adulto , Encéfalo/fisiologia , Feminino , Humanos , Julgamento/fisiologia , Masculino , Semântica
19.
Sci Rep ; 8(1): 13142, 2018 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-30177772

RESUMO

Violet laser diode (VLD) based ultrahigh-speed free-space optical (FSO) system is demonstrated for point-to-point data transmission. By directly encoding the VLD with 64-quadrature amplitude modulation discrete multi-tone (64-QAM DMT) data stream for optical wireless communication through 0.5-10 m in free space, the point-to-point VLD-based FSO link allows delivering the 64-QAM DMT data at an ultrahigh bit rate of up to 26.4 Gbps. After receiving with a high-speed p-i-n photodiode, such a VLD-FSO link can provide clear constellation plot with error vector magnitude (EVM) of 8.57%, signal-to-noise ratio (SNR) of 21.34 dB and bit error ratio (BER) of 3.17 × 10-3 under forward-error-correction criterion. The EVM increases from 8.8% to 9.4% and the SNR decreases from 21.1 to 20.6 dB to slightly degrade the reachable data rate from 25.8 to 24 Gbit/s with transmission distance lengthening from 3 to 10 m.

20.
Cogn Neurosci ; 9(3-4): 151-166, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30124357

RESUMO

Brain stimulation technologies have seen increasing application in basic science investigations, specifically toward the goal of improving memory function. However, proposals concerning the neural mechanisms underlying cognitive enhancement often rely on simplified notions of excitation. As a result, most applications examining the effects of transcranial magnetic stimulation (TMS) on functional neuroimaging measures have been limited to univariate analyses of brain activity. We present here analyses using representational similarity analysis (RSA) and encoding-retrieval similarity (ERS) analysis to quantify the effect of TMS on memory representations. To test whether an increase in local excitability in PFC can have measurable influences on upstream representations in earlier temporal memory regions, we compared 1 and 5Hz stimulation to the left dorsolateral PFC (DLPFC). We found that 5Hz rTMS, relative to 1Hz, had multiple effects on neural representations: 1) greater representational similarity during both encoding and retrieval in ventral stream regions, 2) greater ERS in the hippocampus, and, critically, 3) increasing ERS in MTL was correlated with increasing univariate activity in DLPFC, and greater functional connectivity for hits than misses between these regions. These results provide the first evidence of rTMS modulating semantic representations and strengthen the idea that rTMS may affect the reinstatement of previously experienced events in upstream regions.


Assuntos
Hipocampo/fisiologia , Memória/fisiologia , Córtex Pré-Frontal/fisiologia , Lobo Temporal/fisiologia , Estimulação Magnética Transcraniana , Idoso , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Rememoração Mental/fisiologia , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...