Berthelsenhernandez0838

In this paper, a novel experimental set-up was developed that measures the absorption coefficient. The proposed system was evaluated in an agar-based gel phantom. The new experimental system provides accurate and fast measurement of the rate of temperature change within the phantom. The rate of temperature change was measured using thermocouple and was confirmed using MR thermometry. An ultrasonic transducer with a broad beam was used in order to reduce the conduction effect. The absorption coefficient of the agar-based phantom was 0.26 dB/cm-MHz using 4% agar, 30% evaporated milk and 4% silica. The absorption coefficient increased by increasing the volume of the evaporated milk, and agar. The absorption coefficient increased at low silica concentration (4%). By proper selection of evaporated milk, agar and silica concentration, it is possible to achieve similar coefficient like in soft tissues. Acoustic absorption measurement is considered as a difficult measurement in ultrasonics because obtaining the precise temperature change in the focus is challenging. Due to the quick and accurate placement of the thermocouple at the ultrasonic beam, it is possible with the proposed system to perform absorption measurement is less than one minute. BACKGROUND Two-dimensional ultrasounds (2D US) have low reproducibility of given images in later sessions and often depend on the operator's experience. PURPOSE Due to difficulties in reproducing images in 2D US separated in time, a device to track the position of the ultrasound probe was created. read more This device aims to measure the probe position angle in two axes for 2D US to provide accurate repositioning of the 2D US probe for repeatability of the desired imaging plane. MATERIALS AND METHODS The device uses an inclinometer with an Arduino microprocessor to determine the angle of the ultrasound probe to subsequently establish the specific position coordinates of the probe. To test the effectiveness of this device, a 2D US probe was placed on a frontal burr hole of a neonatal swine to image the brain. RESULTS When fixing the point of contact, using the probe with the angle sensing device helped the operator reproduce images that were both visually and positionally similar. This attachment allows the probe to return to the same image with at least 95% similarity in between different sessions, based on evaluations using an image analysis Matlab program. The sensor can return images of the same location with landmarks within the tolerance of 1.400°. CONCLUSION This device could potentially improve 2D US image reproducibility such that accuracy of images between sessions is increased, thereby increasing the reproducibility of 2D US in diagnostic and interventional procedures. Elastic guided waves (GW) can be profitably used in non-destructive evaluation and in structural health monitoring of plate-like structures. Nevertheless, the multi-modal and dispersive behaviour of GW often leads to difficult interpretation of typically measured time-dependent signals. The development of efficient simulation tools appears necessary to better understand complex phenomena involved and to optimize testing configurations. Here, a semi-analytical modal method is proposed to compute GW displacement fields in finite plates radiated by an arbitrary finite-sized source of surface stresses. It takes into account GW reflections and mode conversions at plate boundaries. As far as computation efficiency is concerned, this method is independent of the length of propagation paths, allowing to efficiently address configurations involving long range propagation. Predicted results are given as sums of modal contributions to ease their interpretation. The model is validated by comparing its predictions to those computed by a transient finite-element code. Plane Wave Imaging is a fast imaging method used in ultrasound, which allows a high frame rate, but with compromised image quality when a single wave is used. In this work a learning-based approach was used to obtain improved image quality. The entire process of beamforming and speckle reduction was embedded in a single deep convolutional network, and trained with two types of simulated data. The network architecture was designed based on traditional physical considerations of the ultrasonic image formation pipe. As such, it includes beamforming with spatial matched filters, envelope detection, and a speckle reduction stage done in log-signal representation, with all stages containing trainable parameters. The approach was tested on the publicly available PICMUS datasets, achieving axial and lateral full-width-half-maximum (FWHM) resolution values of 0.22 mm and 0.35 mm respectively, and a Contrast to Noise Ratio (CNR) metric of 16.75 on the experimental datasets. BACKGROUND AND OBJECTIVES The examination of the fundus allows to evaluate retinal the microcirculation in vivo. We assess the reliability and validity of ALTAIR software, and to evaluate its clinical relevance by the association of thickness, area and length of the retinal vessels with other measures of vascular structure and function, target organ damage and cardiovascular risk. METHODS Cross-sectional study involving a total of 250 subjects aged 62 ± 9 years, 51 % males. In a random subsample of 60 subjects (118 retinographies), we estimated the intraobserver, interobserver and interdevice intraclass correlation coefficients (ICC) of the measurements of retinal vascular thickness, area and length in 3 concentric circles. Concurrent validity was assessed with all 250 subjects (495 retinographies), analysing the relationship to age, blood pressure, target organ damage, vascular structure and function, and cardiovascular risk. RESULTS Of the sample, 69 % were diagnosed with hypertension and 17 % with diabetes. Intraobserver ICC ranged from 0.640 for venous length to 0.906 for arterial area. Interobserver ICC ranged from 0.809 for arterial length to 0.916 for venous area, and interdevice ICC for arteriovenous ratio (AVR) was 0.887, thickness of arteries 0.590 and vein thickness 0.677. We found a moderate correlation between retinal vascular parameters and vascular structure and function, and target organ damage. In multiple linear regression analysis, the association with blood pressure, albumin/creatinine ratio, carotid intima-media thickness and cardiovascular risk is maintained. CONCLUSION The ALTAIR tool has been useful for analysing the thickness, area and length of retinal vessels, with adequate reliability and a concomitant association of retinal vessel measurements with other cardiovascular parameters and cardiovascular risk. Therefore, in addition to thickness, the area and length of retinal vessels could also play a role in the prediction of cardiovascular risk. Major depressive disorder (MDD) is a leading cause of disability worldwide, with a poorly known pathophysiology and sub-optimal treatment, based on serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors. We review existing theories on MDD, paying special attention to the role played by the ventral anterior cingulate cortex (vACC) or its rodent equivalent, infralimbic cortex (IL), which tightly control the activity of brainstem monoamine neurons (including raphe 5-HT neurons) via descending afferents. Further, astrocytes regulate excitatory synapse activity via glutamate reuptake through astrocytic transporters EAAT1 and EAAT2 (GLAST and GLT-1 in rodents), and alterations of astrocyte number/function have been reported in MDD patients and suicide victims. We recently assessed the impact of reducing GLAST/GLT-1 function in IL on emotional behavior and serotonergic function in rodents. The acute pharmacological blockade of GLT-1 with dihydrokainate (DHK) in rat IL evoked an antidepressant-like effect mediated by local AMPA-R activation and a subsequent enhancement of serotonergic function. No effects were produced by DHK microinfusion in prelimbic cortex (PrL). In the second model, a moderate small interfering RNAs (siRNA)-induced reduction of GLAST and GLT-1 expression in mouse IL markedly increased local glutamatergic neurotransmission and evoked a depressive-like phenotype (reversed by citalopram and ketamine), and reduced serotonergic function and BDNF expression in cortical/hippocampal areas. As for DHK, siRNA microinfusion in PrL did not evoke behavioral/neurochemical effects. link2 Overall, both studies support a critical role of the astrocyte-neuron communication in the control of excitatory neurotransmission in IL, and subsequently, on emotional behavior, via the downstream associated changes on serotonergic function. Three undescribed triterpenes and four previously unreported saponins, along with two known ones, were isolated from shells of Xanthoceras sorbifolium (Sapindaceae). link3 Their structures were elucidated by the interpretation of 1D and 2D NMR data. The nitric oxide (NO) assay revealed that 28-O-isobutyryl-21-O-angeloyl-R1-barrigenol and 3-O-β-D-6-O-methylglucuronopyranosyl-21,22-di-O-angeloyl-R1-barrigenol possessed stronger inhibitory effects on LPS-induced NO overproduction (IC50 = 18.5 ± 1.2 and 28.2 ± 1.8 μM, respectively) than the positive drug minocycline (IC50 = 30.1 ± 1.3 μM) in activated BV2 cells. Western blot, RT-qPCR, and docking experiments further validated that the regulation of iNOS and IL-1β expressions was involved in the anti-neuroinflammatory effects of these two compounds. Herein, we report surface coarsened titanium dioxide (TiO2) nanobelts with anatase/rutile heterophase junctions via a facile hydrothermal/calcination method for simultaneous hydrogen (H2) and oxygen (O2) productions from pure water, with excellent production rates of 0.614 and 0.297 mmol h-1 g-1 with platinum (Pt)/cobalt phosphide (CoP) as cocatalysts, respectively. Besides, the TiO2 nanobelts-900 °C with anatase/rutile heterophase junctions show a notable improvement in photocatalytic H2 and O2 production than pure anatase TiO2 nanobelts (TiO2 nanobelts-600 °C, 700 °C and 800 °C) and pure rutile TiO2 nanobelts (TiO2 nanobelts-1000 °C). The anatase/rutile heterophase junctions could effectively stimulate the transfer of electrons from rutile to anatase and then to Pt, and H2 generation on the surface of Pt. In the meantime, the holes can be transferred from anatase to rutile and then to CoP, and water oxidation on CoP's surface. Cytotoxic drugs tend to have substantial side effects on healthy tissues leading to systemic toxicity, limited tolerated doses and reduced drug efficacy. A prominent research area focuses on encapsulating cytotoxic drugs for targeted delivery to cancer tissues. However, existing carriers suffer from low drug loading levels and high drug leaching both when circulating systemically and when accumulating in non-target organs. These challenges mean that only few encapsulation technologies for delivery of cytotoxic drugs have been adopted for clinical use. Recently, we have demonstrated efficient manufacture of impermeable metal-shell/liquid core microcapsules that permit localised delivery by triggering release with ultrasound. This method has the potential to improve on existing methods for localised drug delivery because itWe demonstrate here the further miniaturization of both the emulsion droplet template and the thickness of the surrounding metal shell to the nanoscale in an attempt to take advantage of the EPR effect and the excretion of nanoparticles by the hepatobiliary system.