Advances in techniques for recording large-scale brain activity contribute to both the elucidation of neurophysiological principles and the development of brain-machine interfaces (BMIs). Here we ...describe a neurophysiological paradigm for performing tethered and wireless large-scale recordings based on movable volumetric three-dimensional (3D) multielectrode implants. This approach allowed us to isolate up to 1,800 neurons (units) per animal and simultaneously record the extracellular activity of close to 500 cortical neurons, distributed across multiple cortical areas, in freely behaving rhesus monkeys. The method is expandable, in principle, to thousands of simultaneously recorded channels. It also allows increased recording longevity (5 consecutive years) and recording of a broad range of behaviors, such as social interactions, and BMI paradigms in freely moving primates. We propose that wireless large-scale recordings could have a profound impact on basic primate neurophysiology research while providing a framework for the development and testing of clinically relevant neuroprostheses.
Soft tissue sample thickness measurement is one of the major sources of differences between mechanical responses published by different groups. New method for the estimation of unloaded sample ...thickness of soft tissues is proposed in this study. Ten 30 × 30 mm and ten 20 × 20 mm samples of porcine anterior thoracic aortas were loaded by gradually increased radial force. Their deformed thickness was then recorded in order to generate a pressure-thickness response. Next, the limit pressure to which the response can be considered linear was estimated. Line was fitted to the linear part of the curve and extrapolated towards zero pressure to estimate unloaded thickness (7 kPa fit). For comparison, data near zero pressure were fitted separately and extrapolated towards zero (Near Zero fit). The limit pressure for the linearity of the response was around 7 kPa. The Unloaded thickness for 30 × 30 mm samples was 2.68 ± 0.31 mm and 2.68 ± 0.3 mm for Near Zero fit and 7 kPa fit, respectively. The Unloaded thickness for 20 × 20 mm samples was 2.60 ± 0.35 mm and 2.59 ± 0.35 mm for Near Zero fit and 7 kPa fit, respectively. The median of thickness difference between smaller and larger samples was not found statistically different. Proposed method can estimate unloaded undeformed sample thickness quickly and reliably.
The rational geometric and topological organization of mechanical metamaterials allows for unconventional responses to external loads. These materials exhibit a coupling between deformation in ...orthogonal directions governed by Poisson's ratio, which, in turn, can be precisely adjusted through the deliberate selection of specific geometrical parameters within the metamaterial's structure. Although certain structural motifs may even enable a negative Poisson's ratio, it is conventionally assumed to remain constant or near-constant during deformation. In this study, we introduce a novel design concept that enables metamaterials to switch the sign of Poisson's ratio during loading, specifically at predetermined compressive strain levels, by harnessing self-contact between individual elements of the metamaterial. Through the integration of finite element simulations and experimental testing, we establish a direct correlation between the geometrical parameters of the unit cell and the mechanical response of the metamaterial. This correlation enables us to engineer samples with desired functionality and we present a discrete scales demonstrator that exploits this switchable behavior.
Our purpose was to physically characterize the surface, and the subsurface, of a macro- and micro-textured titanium grade 5 dental implant surface obtained by etching only, without sandblasting. The ...topography, surface roughness, as well as the surface structure and subsurface distribution of elements, were determined by scanning electronic microscopy (SEM), non-contact profilometry, X-ray diffraction (XRD), and a concentration profile performed by Auger electron spectroscopy (AES). The hydrogen concentration in the implants was measured; the ability to generate nanostructures when stored in deionized water was also investigated. Under SEM, the surface resembled a sandblasted and etched titanium surface with its typical macro- and micro-texture; roughness was moderate with average roughness (Sa) 1.29 µm. No titanium hydride was found at the implant surface and no enrichment of any alloying element was identified at the surface and subsurface. Hydrogen concentration was 79 ppm, within the normative tolerance (<130 ppm). After storage in water for 6 months, densely packed finger-like nanostructures were observed. The clinical advantage of this textured titanium alloy surface is that it displays the typical macro- and micro-features of a moderately rough sandblasted and etched (SLA) titanium surface without leaving behind any foreign sandblasting material.
In this study, the effect of moisture on the elastic and failure properties of elastomeric polyurethane (EPU 40) 3D printed via Vat Photopolymerization was investigated. EPU 40 samples were printed, ...and uniaxial tensile tests were performed on Dry-fresh, Dry-aged (eight months aged), and after various times of being immersed in water (0−8 months). Elastic response, initial stiffness, failure strength, and failure elongation were analyzed. Besides, gravimetric analysis was performed to determine the increase in weight and thickness after water immersion. The elastic response was fitted by the Arruda-Boyce constitutive model. Results show that initial stiffness decreased after immersion (mean 6.8 MPa dry vs. 6.3 MPa immersed p-value 0.002). Contrary, the initial stiffness increased due to physical aging under a dry state from a mean 6.3 MPa to 6.9 MPa (p = 0.006). The same effect was observed for stiffness parameter G of the constitutive model, while the limit stretch parameter λL was not affected by either aging. The 95% confidence intervals for strength and failure stretch were 5.27−9.48 MPa and 2.18−2.86, respectively, and were not affected either by immersion time or by physical aging. The median diffusion coefficient was 3.8·10−12 m^2/s. The immersion time has a significant effect only on stiffness, while oxidative aging has an inverse effect on the mechanical properties compared to water immersion. The transition process is completed within 24 h after immersion.
Collared and white-lipped peccaries are sympatric and are distributed in most of South America and in the humid tropical forests of Mexico and Central America. Historically, these species have been ...used as a source of protein by traditional and/or indigenous human communities, but currently they have been used for legal consumption in different countries. Thus, there has been greater interaction between these wild species and domestic animals and humans, enabling microbial interactions between different niches. The present study presents a systematic review of the literature on the microbial community of collared peccaries and white-lipped peccaries distributed throughout the world, focusing on experimental studies related to the detection of microorganisms as well as the prevalence of the animal species and its characterization of the studied population, in situ or ex situ. Seventy-two studies were selected, mainly in South American countries, related to different species of microorganisms isolated or serologically detected (viruses, bacteria, fungi, and parasites), either as microbiota, pathogens or commensals, many of which are of zoonotic interest, such as
Leptospira
,
Toxoplasma
,
Brucella
, among others. Therefore, these wild mammals are characterized as sentinel agents of anthropic action and require the implementation of studies in relation to their contribution to the spread of microorganisms, being a potential source of amplification and transmission of pathogens.
Several groups have developed brain-machine-interfaces (BMIs) that allow primates to use cortical activity to control artificial limbs. Yet, it remains unknown whether cortical ensembles could ...represent the kinematics of whole-body navigation and be used to operate a BMI that moves a wheelchair continuously in space. Here we show that rhesus monkeys can learn to navigate a robotic wheelchair, using their cortical activity as the main control signal. Two monkeys were chronically implanted with multichannel microelectrode arrays that allowed wireless recordings from ensembles of premotor and sensorimotor cortical neurons. Initially, while monkeys remained seated in the robotic wheelchair, passive navigation was employed to train a linear decoder to extract 2D wheelchair kinematics from cortical activity. Next, monkeys employed the wireless BMI to translate their cortical activity into the robotic wheelchair's translational and rotational velocities. Over time, monkeys improved their ability to navigate the wheelchair toward the location of a grape reward. The navigation was enacted by populations of cortical neurons tuned to whole-body displacement. During practice with the apparatus, we also noticed the presence of a cortical representation of the distance to reward location. These results demonstrate that intracranial BMIs could restore whole-body mobility to severely paralyzed patients in the future.
African swine fever (ASF) is a transboundary infectious disease that can infect wild and domestic swine and requires enhanced surveillance between countries. In Mozambique, ASF has been reported ...across the country, spreading between provinces, mainly through the movement of pigs and their by-products. Subsequently, pigs from bordering countries were at risk of exposure. This study evaluated the spatiotemporal distribution and temporal trends of ASF in swine in Mozambique between 2000 and 2020. During this period, 28,624 cases of ASF were reported across three regions of the country. In total, the northern, central, and southern regions presented 64.9, 17.8, and 17.3% of the total cases, respectively. When analyzing the incidence risk (IR) of ASF per 100,000 pigs, the Cabo Delgado province had the highest IR (17,301.1), followed by the Maputo province (8868.6). In the space-time analysis, three clusters were formed in each region: (i) Cluster A involved the provinces of Cabo Delgado and Nampula (north), (ii) Cluster B involved the province of Maputo and the city of Maputo (south), and (iii) Cluster C consisted of the provinces of Manica and Sofala (central) in 2006. However, when analyzing the temporal trend in the provinces, most were found to be decreasing, except for Sofala, Inhambane, and Maputo, which had a stationary trend. To the best of our knowledge, this is the first study to evaluate the spatial distribution of ASF in Mozambique. These findings will contribute to increasing official ASF control programs by identifying high-risk areas and raising awareness of the importance of controlling the borders between provinces and countries to prevent their spread to other regions of the world.
Bluetongue is caused by the Bluetongue virus (BTV), a member of the genus Orbivirus within the family of the Sedoreoviridae. The virus can spread among sheep herds, increasing economic losses mainly ...due to the viral transmission being carried out by a biological vector directly affected by environmental conditions. In addition to Brazil having different biomes, it is also one of the countries with the most significant environmental commitment in recent years, which may interfere with the biogeography of the disease. Thus, the present study analyzed the spatio-temporal distribution of Bluetongue (BT) in sheep and the detection of regions with a higher risk for the disease in different regions of Brazil between 2013 and 2021. During this study period, five states with official notification for BT were verified: Rio Grande do Sul (228 cases; Incidence Risk/100.000 IR = 5.7), Rio de Janeiro (116 cases; IR = 251.7), Amazonas (17 cases; IR = 41.12), Paraná (12 cases; IR = 2.0), and Minas Gerais (7 cases; IR = 3.7). When evaluating the annual distribution, Rio de Janeiro stood out in 2013, with an IR = 217.3, whereas Amazonas had the highest mortality rate (37.13%) in 2017. However, fatality rates of 100% were found in Rio Grande do Sul (for 53 cases) in 2017 and in Paraná (for 1 case) in 2019. The months with the highest case notifications were February and April, highlighting Rio Grande do Sul and Rio de Janeiro as the main states that contributed to these notifications. We observed the formation of two clusters of high risk of the disease: i) cluster A (Relative Risk RRs = 63.04 between 2013 and 2015), formed by six states comprising all states from the South and part of the Southeast and Midwest, and, ii) cluster B (RRs = 180.52, in 2017), formed only by the state of Amazonas. Based on the results, BT is not evenly distributed among Brazilian states and concentrated in the southern region, especially Rio Grande do Sul. Important control and surveillance measures must be instituted to optimize national animal health programs in Brazil.
•In Brazil, Rio Grande do Sul had the highest number of bluetongue cases.•Rio de Janeiro had the highest incidence risk (251.7/100,000) for bluetongue.•Primary cluster was formed covering six states between 2013 and 2015.•Secondary cluster was formed covering Amazonas in 2017.
Objectives/Hypothesis
The diagnosis of sialolithiasis is, along with clinical presentation, based on different imaging techniques and more invasive procedures such as sialendoscopy. The aim of the ...study was to analyze the potential of cone beam computed tomography (CBCT) for the diagnosis of sialolithiasis and to compare the results with those of sonography and sialendoscopy.
Study Design
Retrospective analysis.
Methods
The data of 43 patients with suspected sialolithiasis were evaluated retrospectively. All patients had CBCT and sonographic imaging and received sialendoscopy to confirm and possibly treat sialolithiasis.
Results
Sonography, CBCT, and sialendoscopy together indicated sialolithiasis in 33 patients. The mean maximum diameter of the extracted sialoliths did not significantly differ between the three diagnostics. Each diagnostic tool showed an excellent specificity and positive predictive value. Sensitivity and negative predictive value were best in sialendoscopy (94% resp. 83%), followed by CBCT (79% resp. 56%) and then sonography (70% resp. 47%).
Conclusion
The results revealed that CBCT is capable of diagnosing sialoliths in general and tended to be more sensitive than sonography. However, in view of the radiation exposure, the use of CBCT must be critically weighed and should not be used as a primary option.
Level of Evidence
4. Laryngoscope, 125:1098–1101, 2015
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