Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 344
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(9): e2210839120, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36812207

RESUMO

During visual search, it is important to reduce the interference of distracting objects in the scene. The neuronal responses elicited by the search target stimulus are typically enhanced. However, it is equally important to suppress the representations of distracting stimuli, especially if they are salient and capture attention. We trained monkeys to make an eye movement to a unique "pop-out" shape stimulus among an array of distracting stimuli. One of these distractors had a salient color that varied across trials and differed from the color of the other stimuli, causing it to also pop-out. The monkeys were able to select the pop-out shape target with high accuracy and actively avoided the pop-out color distractor. This behavioral pattern was reflected in the activity of neurons in area V4. Responses to the shape targets were enhanced, while the activity evoked by the pop-out color distractor was only briefly enhanced, directly followed by a sustained period of pronounced suppression. These behavioral and neuronal results demonstrate a cortical selection mechanism that rapidly inverts a pop-out signal to "pop-in" for an entire feature dimension thereby facilitating goal-directed visual search in the presence of salient distractors.


Assuntos
Percepção de Cores , Córtex Visual , Animais , Percepção de Cores/fisiologia , Haplorrinos , Atenção/fisiologia , Movimentos Oculares , Córtex Visual/fisiologia , Tempo de Reação/fisiologia , Percepção Visual/fisiologia
2.
Proc Natl Acad Sci U S A ; 119(42): e2213080119, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36223395

RESUMO

Neurons in visual cortical areas primary visual cortex (V1) and V4 are adaptive processors, influenced by perceptual task. This is reflected in their ability to segment the visual scene into task-relevant and task-irrelevant stimulus components and by changing their tuning to task-relevant stimulus properties according to the current top-down instruction. Differences between the information represented in each area were seen. While V1 represented detailed stimulus characteristics, V4 filtered the input from V1 to carry the binary information required for the two-alternative judgement task. Neurons in V1 were activated at locations where the behaviorally relevant stimulus was placed well outside the grating-mapped receptive field. By systematically following the development of the task-dependent signals over the course of perceptual learning, we found that neuronal selectivity for task-relevant information was initially seen in V4 and, over a period of weeks, subsequently in V1. Once the learned information was represented in V1, on any given trial, task-relevant information appeared initially in V1 responses, followed by a 12-ms delay in V4. We propose that the shifting representation of learned information constitutes a mechanism for systems consolidation of memory.


Assuntos
Córtex Visual , Aprendizagem/fisiologia , Neurônios/fisiologia , Estimulação Luminosa , Córtex Visual/fisiologia , Percepção Visual/fisiologia
3.
Proc Natl Acad Sci U S A ; 119(40): e2202564119, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161937

RESUMO

A large body of recent work suggests that neural representations in prefrontal cortex (PFC) are changing over time to adapt to task demands. However, it remains unclear whether and how such dynamic coding schemes depend on the encoded variable and are influenced by anatomical constraints. Using a cued attention task and multivariate classification methods, we show that neuronal ensembles in PFC encode and retain in working memory spatial and color attentional instructions in an anatomically specific manner. Spatial instructions could be decoded both from the frontal eye field (FEF) and the ventrolateral PFC (vlPFC) population, albeit more robustly from FEF, whereas color instructions were decoded more robustly from vlPFC. Decoding spatial and color information from vlPFC activity in the high-dimensional state space indicated stronger dynamics for color, across the cue presentation and memory periods. The change in the color code was largely due to rapid changes in the network state during the transition to the delay period. However, we found that dynamic vlPFC activity contained time-invariant color information within a low-dimensional subspace of neural activity that allowed for stable decoding of color across time. Furthermore, spatial attention influenced decoding of stimuli features profoundly in vlPFC, but less so in visual area V4. Overall, our results suggest that dynamic population coding of attentional instructions within PFC is shaped by anatomical constraints and can coexist with stable subspace coding that allows time-invariant decoding of information about the future target.


Assuntos
Atenção , Córtex Pré-Frontal , Animais , Atenção/fisiologia , Macaca mulatta , Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologia
4.
J Neurosci ; 43(22): 4129-4143, 2023 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-37185098

RESUMO

The mechanisms involved in transforming early visual signals to curvature representations in V4 are unknown. We propose a hierarchical model that reveals V1/V2 encodings that are essential components for this transformation to the reported curvature representations in V4. Then, by relaxing the often-imposed prior of a single Gaussian, V4 shape selectivity is learned in the last layer of the hierarchy from Macaque V4 responses. We found that V4 cells integrate multiple shape parts from the full spatial extent of their receptive fields with similar excitatory and inhibitory contributions. Our results uncover new details in existing data about shape selectivity in V4 neurons that with additional experiments can enhance our understanding of processing in this area. Accordingly, we propose designs for a stimulus set that allow removing shape parts without disturbing the curvature signal to isolate part contributions to V4 responses.SIGNIFICANCE STATEMENT Selectivity to convex and concave shape parts in V4 neurons has been repeatedly reported. Nonetheless, the mechanisms that yield such selectivities in the ventral stream remain unknown. We propose a hierarchical computational model that incorporates findings of the various visual areas involved in shape processing and suggest mechanisms that transform the shape signal from low-level features to convex/concave part representations. Learning shape selectivity from Macaque V4 responses in the final processing stage in our model, we found that V4 neurons integrate shape parts from the full spatial extent of their receptive field with both facilitatory and inhibitory contributions. These results reveal hidden information in existing V4 data that with additional experiments can enhance our understanding of processing in V4.


Assuntos
Percepção de Forma , Córtex Visual , Animais , Córtex Visual/fisiologia , Percepção de Forma/fisiologia , Macaca , Neurônios/fisiologia , Encéfalo , Vias Visuais/fisiologia , Estimulação Luminosa
5.
J Neurosci ; 43(29): 5378-5390, 2023 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-37369590

RESUMO

Radial frequency (RF) patterns, created by sinusoidal modulations of a circle's radius, are processed globally when RF is low. These closed shapes therefore offer a useful way to interrogate the human visual system for global processing of curvature. RF patterns elicit greater responses than those to radial gratings in V4 and more anterior face-selective regions of the ventral visual pathway. This is largely consistent with work on nonhuman primates showing curvature processing emerges in V4, but is evident also higher up the ventral visual stream. Rather than contrasting RF patterns with other stimuli, we presented them at varied frequencies in a regimen that allowed tunings to RF to be derived from 8 human participants (3 female). We found tuning to low RF in lateral occipital areas and to some extent in V4. In a control experiment, we added a high-frequency ripple to the stimuli disrupting the local contour. Low-frequency tuning to these stimuli remained in the ventral visual stream, underscoring its role in global processing of shape curvature. We then used representational similarity analysis to show that, in lateral occipital areas, the neural representation was related to stimulus similarity, when it was computed with a model that captured how stimuli are perceived. We therefore show that global processing of shape curvature emerges in the ventral visual stream as early as V4, but is found more strongly in lateral occipital regions, which exhibit responses and representations that relate well to perception.SIGNIFICANCE STATEMENT We show that tuning to low radial frequencies, known to engage global shape processing mechanisms, was localized to lateral occipital regions. When low-level stimulus properties were accounted for such tuning emerged in V4 and LO2 in addition to the object-selective region LO. We also documented representations of global shape properties in lateral occipital regions, and these representations were predicted well by a proxy of the perceptual difference between the stimuli.


Assuntos
Percepção de Forma , Vias Visuais , Animais , Humanos , Feminino , Vias Visuais/fisiologia , Rádio (Anatomia) , Reconhecimento Visual de Modelos/fisiologia , Lobo Occipital , Percepção de Forma/fisiologia , Estimulação Luminosa
6.
Small ; 20(11): e2306615, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37932020

RESUMO

Aqueous zinc-ion batteries (AZIBs) are considered to be a rising star in the large-scale energy storage area because of their low cost and environmental friendliness properties. However, the limited electrochemical performance of the cathode and severe zinc dendrite of the anode severely hinder the practical application of AZIBs. Herein, a novel 3D interconnected VS2 ⊥V4 C3 Tx heterostructure material is prepared via one-step solvothermal method. Morphological and structural characterizations show that VS2 nanosheets are uniformly and dispersedly distributed on the surface of the V4 C3 MXene substrate, which can effectively suppress volume change of the VS2 . Owing to the open heterostructure along with the high conductivity of V4 C3 MXene, the VS2 ⊥V4 C3 Tx cathode shows a high specific capacity of 273.9 mAh g-1 at 1 A g-1 and an excellent rate capability of 143.2 mAh g-1 at 20 A g-1 . The V4 C3 MXene can also effectively suppress zinc dendrite growth when used as protective layer for the Zn anode, making the V4 C3 Tx @Zn symmetric cell with a stable voltage profile for ≈1700 h. Benefitting from the synergistic modification effect of V4 C3 MXene on both the cathode and anode, the VS2 ⊥V4 C3 Tx ||V4 C3 Tx @Zn battery exhibits a long cycling lifespan of 5000 cycles with a capacity of 157.1 mAh g-1 at 5A g-1 .

7.
Small ; 20(22): e2311029, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38152924

RESUMO

Vanadium-based cathode materials have attracted great attention in aqueous zinc-ion batteries (AZIBs). However, the inferior ion transport and cyclic stability due to the strong Coulomb interaction between Zn2+ and the lattice limit their further application. In this work, CO2 molecules are in situ embedded in the interlayer structure of NH4V4O10 by decomposing excess H2C2O4·2H2O in the main framework, obtaining an ion-molecule co-confining NH4V4O10 for AZIB cathode material. The introduced CO2 molecules expanded the interlayer spacing of NH4V4O10, broadened the diffusion channel of Zn2+, and stabilized the structure of NH4V4O10 as the interlayer pillars together with NH 4 + ${\mathrm{NH}}_4^ + $ , which effectively improved the Zn2+ diffusion kinetics and cycle stability of the electrode. In addition, the binding between NH 4 + ${\mathrm{NH}}_4^ + $ and the host framework is stabilized via hydrogen bonds with CO2 molecules. NVO-CO2-0.8 exhibited excellent specific capacity (451.1 mAh g-1 at 2 A g-1), cycle stability (214.0 mAh g-1 at 10 A g-1 after 1000 cycles) and rate performance. This work provides new ideas and approaches for optimizing vanadium-based materials with high-performance AZIBs.

8.
Small ; 20(28): e2309412, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38342678

RESUMO

Ammonium vanadates, featuring an N─H···O hydrogen bond network structure between NH4 + and V─O layers, have become popular cathode materials for aqueous zinc-ion batteries (AZIBs). Their appeal lies in their multi-electron transfer, high specific capacity, and facile synthesis. However, a major drawback arises as Zn2+ ions tend to form bonds with electronegative oxygen atoms between V─O layers during cycling, leading to irreversible structural collapse. Herein, Li+ pre-insertion into the intermediate layer of NH4V4O10 is proposed to enhance the electrochemical activity of ammonium vanadate cathodes for AZIBs, which extends the interlayer distance of NH4V4O10 to 9.8 Å and offers large interlaminar channels for Zn2+ (de)intercalation. Moreover, Li+ intercalation weakens the crystallinity, transforms the micromorphology from non-nanostructured strips to ultrathin nanosheets, and increases the level of oxygen defects, thus exposing more active sites for ion and electron transport, facilitating electrolyte penetration, and improving electrochemical kinetics of electrode. In addition, the introduction of Li+ significantly reduces the bandgap by 0.18 eV, enhancing electron transfer in redox reactions. Leveraging these unique advantages, the Li+ pre-intercalated NH4V4O10 cathode exhibits a high reversible capacity of 486.1 mAh g-1 at 0.5 A g-1 and an impressive capacity retention rate of 72% after 5,000 cycles at 5 A g-1.

9.
BMC Infect Dis ; 24(1): 494, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745289

RESUMO

BACKGROUND: Brain-heart infusion agar supplemented with 4 µg/mL of vancomycin (BHI-V4) was commonly used for the detection of heterogeneous (hVISA) and vancomycin-intermediate Staphylococcus aureus (VISA). However, its diagnostic value remains unclear. This study aims to compare the diagnostic accuracy of BHI-V4 with population analysis profiling with area under the curve (PAP-AUC) in hVISA/VISA. METHODS: The protocol of this study was registered in INPLASY (INPLASY2023120069). The PubMed and Cochrane Library databases were searched from inception to October 2023. Review Manager 5.4 was used for data visualization in the quality assessment, and STATA17.0 (MP) was used for statistical analysis. RESULTS: In total, eight publications including 2153 strains were incorporated into the meta-analysis. Significant heterogeneity was evident although a threshold effect was not detected across the eight studies. The summary receiver operating characteristic (SROC) was 0.77 (95% confidence interval [CI], 0.74-0.81). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic score and diagnostic odds ratio were 0.59 (95% CI: 0.46-0.71), 0.96 (95%CI: 0.83-0.99), 14.0 (95% CI, 3.4-57.1), 0.43 (95%CI, 0.32-0.57), 3.48(95%CI, 2.12-4.85) and 32.62 (95%CI, 8.31-128.36), respectively. CONCLUSION: Our study showed that BHI-V4 had moderate diagnostic accuracy for diagnosing hVISA/VISA. However, more high-quality studies are needed to assess the clinical utility of BHI-V4.


Assuntos
Antibacterianos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas , Staphylococcus aureus , Vancomicina , Humanos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/diagnóstico , Vancomicina/farmacologia , Antibacterianos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Sensibilidade e Especificidade , Resistência a Vancomicina , Meios de Cultura , Área Sob a Curva
10.
Environ Res ; 241: 117548, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37939803

RESUMO

The retreat of glaciers in Antarctica has increased in the last decades due to global climate change, influencing vegetation expansion, and soil physico-chemical and biological attributes. However, little is known about soil microbiology diversity in these periglacial landscapes. This study characterized and compared bacterial and fungal diversity using metabarcoding of soil samples from the Byers Peninsula, Maritime Antarctica. We identified bacterial and fungal communities by amplification of bacterial 16 S rRNA region V3-V4 and fungal internal transcribed spacer 1 (ITS1). We also applied 14C dating on soil organic matter (SOM) from six profiles. Physico-chemical analyses and attributes associated with SOM were evaluated. A total of 14,048 bacterial ASVs were obtained, and almost all samples had 50% of their sequences assigned to Actinobacteriota and Proteobacteria. Regarding the fungal community, Mortierellomycota, Ascomycota and Basidiomycota were the main phyla from 1619 ASVs. We found that soil age was more relevant than the distance from the glacier, with the oldest soil profile (late Holocene soil profile) hosting the highest bacterial and fungal diversity. The microbial indices of the fungal community were correlated with nutrient availability, soil reactivity and SOM composition, whereas the bacterial community was not correlated with any soil attribute. The bacterial diversity, richness, and evenness varied according to presence of permafrost and moisture regime. The fungal community richness in the surface horizon was not related to altitude, permafrost, or moisture regime. The soil moisture regime was crucial for the structure, high diversity and richness of the microbial community, specially to the bacterial community. Further studies should examine the relationship between microbial communities and environmental factors to better predict changes in this terrestrial ecosystem.


Assuntos
Camada de Gelo , Microbiota , Regiões Antárticas , Fungos/genética , Bactérias/genética , Solo/química , Microbiologia do Solo
11.
J Neurosci ; 42(50): 9343-9355, 2022 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-36396403

RESUMO

The Pearson correlation coefficient squared, r 2, is an important tool used in the analysis of neural data to quantify the similarity between neural tuning curves. Yet this metric is biased by trial-to-trial variability; as trial-to-trial variability increases, measured correlation decreases. Major lines of research are confounded by this bias, including those involving the study of invariance of neural tuning across conditions and the analysis of the similarity of tuning across neurons. To address this, we extend an estimator, [Formula: see text], that was recently developed for estimating model-to-neuron correlation, in which a noisy signal is compared with a noise-free prediction, to the case of neuron-to-neuron correlation, in which two noisy signals are compared with each other. We compare the performance of our novel estimator to a prior method developed by Spearman, commonly used in other fields but widely overlooked in neuroscience, and find that our method has less bias. We then apply our estimator to demonstrate how it avoids drastic confounds introduced by trial-to-trial variability using data collected in two prior studies (macaque, both sexes) that examined two different forms of invariance in the neural encoding of visual inputs-translation invariance and fill-outline invariance. Our results quantify for the first time the gradual falloff with spatial offset of translation-invariant shape selectivity within visual cortical neuronal receptive fields and offer a principled method to compare invariance in noisy biological systems to that in noise-free models.SIGNIFICANCE STATEMENT Quantifying the similarity between two sets of averaged neural responses is fundamental to the analysis of neural data. A ubiquitous metric of similarity, the correlation coefficient, is attenuated by trial-to-trial variability that arises from many irrelevant factors. Spearman recognized this problem and proposed corrected methods that have been extended over a century. We show this method has large asymptotic biases that can be overcome using a novel estimator. Despite the frequent use of the correlation coefficient in neuroscience, consensus on how to address this fundamental statistical issue has not been reached. We provide an accurate estimator of the correlation coefficient and apply it to gain insight into visual invariance.


Assuntos
Córtex Visual , Masculino , Feminino , Animais , Córtex Visual/fisiologia , Neurônios/fisiologia , Campos Visuais , Viés , Modelos Neurológicos
12.
J Neurosci ; 42(4): 631-642, 2022 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-34862189

RESUMO

Texture is an important visual attribute for surface pattern discrimination and therefore object segmentation, but the neural bases of texture perception are largely unknown. Previously, we demonstrated that the responses of V4 neurons to naturalistic texture patches are sensitive to four key features of human texture perception: coarseness, directionality, regularity, and contrast. To begin to understand how distinct texture perception emerges from the dynamics of neuronal responses, in 2 macaque monkeys (1 male, 1 female), we investigated the relative contribution of the four texture attributes to V4 responses in terms of the strength and timing of response modulation. We found that the different feature dimensions are associated with different temporal dynamics. Specifically, the response modulation associated with directionality and regularity was significantly delayed relative to that associated with coarseness and contrast, suggesting that the latter are fundamentally simpler feature dimensions. The population of texture-selective neurons could be grouped into multiple clusters based on the combination of feature dimensions encoded, and those subpopulations displayed distinct temporal dynamics characterized by the weighted combinations of multiple features. Finally, we applied a population decoding approach to demonstrate that texture category information can be obtained from short temporal windows across time. These results demonstrate that the representation of different perceptually relevant texture features emerge over time in the responses of V4 neurons. The observed temporal organization provides a framework to interpret how the processing of surface features unfolds in early and midlevel cortical stages, and could ultimately inform the interpretation of perceptual texture dynamics.SIGNIFICANCE STATEMENT To delineate how neuronal responses underlie our ability to perceive visual textures, we related four key perceptual dimensions (coarseness, directionality, regularity, and contrast) of naturalistic textures to the strength and timing of modulation of neuronal responses in area V4, an intermediate stage in the form-processing, ventral visual pathway. Our results provide the first characterization of V4 temporal dynamics for texture encoding along perceptually defined axes.


Assuntos
Neurônios/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Percepção Visual/fisiologia , Animais , Feminino , Macaca , Masculino
13.
J Neurosci ; 42(33): 6408-6423, 2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35840322

RESUMO

Feature selectivity of visual cortical responses measured during passive fixation provides only a partial view of selectivity because it does not account for the influence of cognitive factors. Here we focus on primate area V4 and ask how neuronal tuning is modulated by task engagement. We investigated whether responses to colored shapes during active shape discrimination are simple, stimulus-agnostic, scaled versions of responses during passive fixation, akin to results from attentional studies. Alternatively, responses could be subject to stimulus-specific scaling, that is, responses to different stimuli are modulated differently, resulting in changes in underlying shape/color selectivity. Among 83 well-isolated V4 neurons in two male macaques, only a minority (16 of 83), which were weakly tuned to both shape and color, displayed responses during fixation and discrimination tasks that could be related by stimulus-agnostic scaling. The majority (67 of 83), which were strongly tuned to shape, color, or both, displayed stimulus-dependent response changes during discrimination. For some of these neurons (39 of 83), the shape or color of the stimulus dictated the magnitude of the change, and for others (28 of 83) it was the combination of stimulus shape and color. Importantly, for neurons with one strong and one weak tuning dimension, stimulus-dependent response changes during discrimination were associated with a relative increase in selectivity along the stronger tuning dimension, without changes in tuning peak. These results reveal that more strongly tuned V4 neurons may also be more flexible in their selectivity, and imbalances in selectivity are amplified during active task contexts.SIGNIFICANCE STATEMENT Tuning for stimulus features is typically characterized by recording responses during passive fixation, but cognitive factors, including attention, influence responses in visual cortex. To determine how behavioral engagement influences neuronal responses in area V4, we compared responses to colored shapes during passive fixation and active behavior. For a large fraction of neurons, differences in responses between passive fixation and active behavior depended on the identity of the visual stimulus. For a subgroup of strongly feature-selective neurons, this response modulation was associated with enhanced selectivity for one feature at the expense of selectivity for the other. Such flexibility in tuning strength could improve performance in tasks requiring active judgment of stimuli.


Assuntos
Córtex Visual , Animais , Atenção/fisiologia , Macaca mulatta , Masculino , Neurônios/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/fisiologia
14.
Neuroimage ; 274: 120149, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37191658

RESUMO

Working memory contents are represented in neural activity patterns across multiple regions of the cortical hierarchy. A division of labor has been proposed where more anterior regions harbor increasingly abstract and categorical representations while the most detailed representations are held in primary sensory cortices. Here, using fMRI and multivariate encoding modeling, we demonstrate that for color stimuli categorical codes are already present at the level of extrastriate visual cortex (V4 and VO1), even when subjects are neither implicitly nor explicitly encouraged to categorize the stimuli. Importantly, this categorical coding was observed during working memory, but not during perception. Thus, visual working memory is likely to rely at least in part on categorical representations. SIGNIFICANCE STATEMENT: Working memory is the representational basis for human cognition. Recent work has demonstrated that numerous regions across the human brain can represent the contents of working memory. We use fMRI brain scanning and machine learning methods to demonstrate that different regions can represent the same content differently during working memory. Reading out the neural codes used to store working memory contents, we show that already in sensory cortex, areas V4 and VO1 represent color in a categorical format rather than a purely sensory fashion. Thereby, we provide a better understanding of how different regions of the brain might serve working memory and cognition.


Assuntos
Memória de Curto Prazo , Córtex Visual , Humanos , Córtex Visual/diagnóstico por imagem , Encéfalo , Cognição , Lobo Parietal , Mapeamento Encefálico , Imageamento por Ressonância Magnética , Percepção Visual
15.
J Eukaryot Microbiol ; 70(3): e12966, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36756708

RESUMO

Phytoplankton-bacteria interactions represent the evolution of complex cross-kingdom networks requiring niche specialization of diverse microbes. Unraveling this co-evolutionary process has proven challenging because microbial partnerships are complex, and their assembly can be dynamic as well as scale- and taxon-dependent. Here, we monitored long-term experimental evolution of phytoplankton-bacteria interactions by reintroducing the intact microbiome into an axenized dinoflagellate Alexandrium tamarense to better understand microbiome assembly dynamics and how microbiome composition could shift and stabilize over 15 months. We examined host functioning by growth rate, photosynthetic capability, cell size, and other physiological signatures and compared it to associated microbial communities determined by 16S rRNA gene sequences. Our results showed that microbiome reconstitution did not restore the intact microbiome, instead a distinct microbial community shift to Roseobacter clade was observed in the re-established cultures. In-depth comparisons of microbial interactions revealed no apparent coupling between host physiology and specific bacterial taxa, indicating that highly represented, abundant taxa might not be essential for host functioning. The emergence of highly divergent Roseobacter clade sequences suggests fine-scale microbial dynamics driven by microdiversity could be potentially linked to host functioning. Collectively, our results indicate that functionally comparable microbiomes can be assembled from markedly different, highly diverse bacterial taxa in changing environments.


Assuntos
Microbiota , Fitoplâncton , Filogenia , RNA Ribossômico 16S/genética , Bactérias/genética
16.
BMC Ophthalmol ; 23(1): 61, 2023 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-36774473

RESUMO

BACKGROUND: Toxic anterior segment syndrome (TASS) is a non-infectious inflammation that can occur after any anterior segment procedure. This case report presents two relatively rare late-onset TASS cases after V4c implantable collamer lens (ICL) operation. CASE PRESENTATION: One 25-year-old woman and one 31-year-old woman suddenly had vision loss in monocular for 1 week after biocular V4c ICL operations and with no subjective complaints. They both presented fibrin formation in the anterior chamber such as keratic precipitates and white pus on the surface of the ICL. Fundus examination was normal. After 4 to 5 weeks of topical and oral steroid treatment, visual acuity and fibrin formation in the anterior chamber improved during the follow-up. CONCLUSIONS: TASS should be suspected in any patient during the late period following ICL surgery; Once TASS is diagnosed, adequate treatment with intensive steroid therapy can be implemented.


Assuntos
Miopia , Lentes Intraoculares Fácicas , Feminino , Humanos , Idoso de 80 Anos ou mais , Miopia/cirurgia , Implante de Lente Intraocular/efeitos adversos , Implante de Lente Intraocular/métodos , Acuidade Visual , Câmara Anterior
17.
BMC Ophthalmol ; 23(1): 341, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37525155

RESUMO

BACKGROUND: To compare the 4-year visual outcomes of implantable collamer lens V4c (EVO-ICL) implantation and small incision lenticule extraction (SMILE) for high myopia and astigmatism. METHODS: This retrospective case study included 64 eyes of 40 patients. These patients with preoperative manifest refraction spherical equivalent (SE) between - 6.00 and - 10.00 diopters (D) were screened from the database of SMILE and EVO-ICL implantation procedures in 2015. The ICL group [32 eyes of 19 patients (mean age, 29.6 ± 6.3 years); mean SE, -8.71 ± 1.06 D] and SMILE group [32 eyes of 21 patients (mean age, 27.7 ± 5.6 years); mean SE, -8.35 ± 0.65D] were compared. All patients were then prospectively examined at a four-year follow-up for routine postoperative examinations, higher-order ocular aberrations, retinal image quality and a questionnaire. RESULTS: The safety indexes were 1.15 ± 0.14 and 1.22 ± 0.21 (P = 0.36) for the SMILE and ICL groups, respectively. No eyes lost two or more lines of CDVA in either group. The efficacy indexes were 0.97 ± 0.16 and 0.96 ± 0.19 (P = 0.87), respectively. Twenty-three eyes (72%) in ICL and 26 eyes (81%) in SMILE groups were within ± 0.5 D of the attempted SE (P < 0.01). ICL-treated eyes had significantly less spherical aberration and coma (P < 0.01 and < 0.05, respectively) postoperatively. Halos were the prevalent visual disturbance in both groups. CONCLUSION: SMILE and EVO-ICL implantation provided safe and effective correction of high myopia. SMILE showed slightly better long-term predictability. Mild postoperative visual disturbances were observed after ICL and SMILE at 4-year follow-up.


Assuntos
Lentes Intraoculares , Miopia , Humanos , Adulto Jovem , Adulto , Estudos Retrospectivos , Acuidade Visual , Resultado do Tratamento , Refração Ocular , Miopia/cirurgia , Seguimentos
18.
Clin Exp Hypertens ; 45(1): 2153134, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36484289

RESUMO

We mistakenly diagnosed a patient with pulmonary embolism as ST-elevation acute myocardial infarction. The case complained of chest pain with ST-elevation in leads AVR, III, AVF, V1, V3R, V4R and V5R. In addition, we also found ST- elevation AVR, III>ST- elevation AVF, QIII>QAVF and QV1. Multi-site pulmonary embolism can lead to type 2 myocardial infarction or special type of myocardial infarction with non-obstructive coronary arteries through multiple pathological mechanisms.


Assuntos
Embolia Pulmonar , Infarto do Miocárdio com Supradesnível do Segmento ST , Humanos , Infarto do Miocárdio com Supradesnível do Segmento ST/complicações , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico , Dor no Peito/diagnóstico , Dor no Peito/etiologia , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/diagnóstico por imagem
19.
Sensors (Basel) ; 23(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36904990

RESUMO

Because of societal changes, human activity recognition, part of home care systems, has become increasingly important. Camera-based recognition is mainstream but has privacy concerns and is less accurate under dim lighting. In contrast, radar sensors do not record sensitive information, avoid the invasion of privacy, and work in poor lighting. However, the collected data are often sparse. To address this issue, we propose a novel Multimodal Two-stream GNN Framework for Efficient Point Cloud and Skeleton Data Alignment (MTGEA), which improves recognition accuracy through accurate skeletal features from Kinect models. We first collected two datasets using the mmWave radar and Kinect v4 sensors. Then, we used zero-padding, Gaussian Noise (GN), and Agglomerative Hierarchical Clustering (AHC) to increase the number of collected point clouds to 25 per frame to match the skeleton data. Second, we used Spatial Temporal Graph Convolutional Network (ST-GCN) architecture to acquire multimodal representations in the spatio-temporal domain focusing on skeletal features. Finally, we implemented an attention mechanism aligning the two multimodal features to capture the correlation between point clouds and skeleton data. The resulting model was evaluated empirically on human activity data and shown to improve human activity recognition with radar data only. All datasets and codes are available in our GitHub.

20.
Int Ophthalmol ; 43(12): 4933-4943, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37936000

RESUMO

PURPOSE: To evaluate intermediate and long-term visual outcomes and safety of a phakic intraocular posterior chamber lens with a central hole (ICL V4c) for myopic eyes. METHODS: Retrospective, consecutive case study of patients that uneventfully received a ICL V4c for myopia correction, with a 5-year postoperative follow-up. Department of Ophthalmology, Goethe University Frankfurt, Germany. RESULTS: From 241 eyes that underwent ICL implantation, we included 45 eyes with a mean age at surgery of 33 years ± 6 (18-48 years), with a 5 years follow-up. CDVA improved from 0.05logMAR ± 0.15 CDVA preoperatively to - 0.00 ± 0,07 at 5 years and did not change significantly from 3 to 5 years' time (p = 0.266). The mean spherical equivalent (SE) improved from -10.13D ± 3.39 to - 0.45D ± 0.69. The change in endothelial cell count showed a mean decrease of 1.9% per year throughout the follow-up. Safety and efficacy index were 1.16 and 0.78, respectively. Cataract formation was seen in 2 of 241 eyes (0.8%), but in none of the 45 eyes that finished the 5-year follow-up. CONCLUSIONS: Our data show a good intermediate and long-term stability, efficiency, and safety of ICL V4c phakic lenses in myopic eyes comparable to other known literature.


Assuntos
Miopia , Lentes Intraoculares Fácicas , Humanos , Adulto , Seguimentos , Estudos Retrospectivos , Miopia/cirurgia , Implante de Lente Intraocular , Refração Ocular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA