Revista Jurídica Digital UANDES
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Towards closed-loop tES: a comparison of methods for real time tACS-EEG artifact removal
No full textBackground: Electroencephalogram (EEG) measures electrical activity reflecting temporal changes in the electrical state of neurons and represents the current flow, which is directly modulated when applying transcranial Alternating Current Stimulation (tACS), making these techniques compliment one-another for closed-loop transcranial Electric Stimulation (tES). To date most studies investigating EEG and tACS have been limited to comparing EEG before/after stimulation. Although methods are now available for tACS-artefact removal, to develop closed-loop stimulation protocols these algorithms need to be implemented in real-time. We present here a comparison of performance of existing methods of tACS artifact removal and their suitability for development for closed-loop stimulation.Methods: 5, 10 and 40 Hz tACS was stimulated, using the Neuroconn DC stimulator Plus, at 250 µA and 500 µA on an Fp2-P3 montage for 1 minute at a time during which the subject was asked to perform an Alpha Task (eyes open and close) or a Face/Non-Face visual task. EEG was recorded using 2 different devices (Enobio, Neuroelectrics and NeuroPrax, Neuroconn) at the P4 with the reference and ground electrodes placed at the Cz. tACS artifact was removed from the recorded EEG data using 3 different methods:- NeuroPrax, built in tACS artifact removal algorithm- Superposition using Moving Averages (SMA) [1]- Adaptive Filter (AF)Results: Our results provide an overview of the artifact removal process. Successful reconstruction of EEG data after artifact removal was demonstrated using all 3 methods. Both alpha activity (from alpha test) and N170 ERPs (Face/Non-Face task) were successfully identified after artifact removal. With regards to compatibility with closed-loop stimulation, SMA was found to have the longest convergence time before valid EEG data is presented. Even though the NeuroPrax has almost no convergence time, it is not suitable for closed-loop stimulation as it requires training prior to recording. This does not suit an experimental design where ongoing EEG activity is used to modulate stimulation parameters. All three methods present an artifact at the end of stimulation. Conclusions: Here we compare the performance of all existing methods for real-time tACS artifact removal and find that both SMA and AF are suitable for development of closed-loop stimulation protocols. SMA has higher convergence but AF requires the ‘signal output’ from the stimulator which not all existing products offer. Monitoring neural activity during stimulation is a key step towards development of closed-loop stimulation protocols that can allow for systems capable of customized tES therapy.<br/
Circulating Tumour Cells
No full textFetal growth restriction (FGR) affects around 5% of pregnancies and is associated with significant short- and long-term adverse outcomes. A number of factors can increase the risk of FGR, one of which is poor maternal diet. In terms of pathology, both clinically and in many experimental models of FGR, impaired uteroplacental vascular function is implicated, leading to a reduction in the delivery of oxygen and nutrients to the developing fetus. Whilst mechanisms underpinning impaired uteroplacental vascular function are not fully understood, interventions aimed at enhancing nitric oxide (NO) bioavailability remain a key area of interest in obstetric research. In addition to endogenous NO production from the amino acid l-arginine, via nitric oxide synthase (NOS) enzymes, research in recent years has established that significant NO can be derived from dietary nitrate, via the ‘alternative NO pathway’. Dietary nitrate, abundant in green leafy vegetables and beetroot, can increase NO bioactivity, conferring beneficial effects on cardiovascular function and blood flow. Given the beneficial effects of dietary nitrate supplementation to date in non-pregnant humans and animals, current investigations aim to assess the therapeutic potential of this approach in pregnancy to enhance NO bioactivity, improve uteroplacental vascular function and increase fetal growth
Super-cluster simulations: impact of baryons on the matter power spectrum and weak lensing forecasts for Super-CLASS
No full textWe use a combination of full hydrodynamic and dark matter only simulations to investigate the effect that supercluster environments and baryonic physics have on the matter power spectrum, by re-simulating a sample of supercluster sub-volumes. On large scales we find that the matter power spectrum measured from our supercluster sample has at least twice as much power as that measured from our random sample. Our investigation of the effect of baryonic physics on the matter power spectrum is found to be in agreement with previous studies and is weaker than the selection effect over the majority of scales. In addition, we investigate the effect of targeting a cosmologically non-representative, supercluster region of the sky on the weak lensing shear power spectrum. We do this by generating shear and convergence maps using a line-of-sight integration technique, which intercepts our random and supercluster sub-volumes. We find the convergence power spectrum measured from our supercluster sample has a larger amplitude than that measured from the random sample at all scales. We frame our results within the context of the Super-CLuster Assisted Shear Survey (Super-CLASS), which aims to measure the cosmic shear signal in the radio band by targeting a region of the sky that contains five Abell clusters. Assuming the Super-CLASS survey will have a source density of 1.5 galaxies arcmin−2, we forecast a detection significance of 2.7+1.5−1.22.7−1.2+1.5 , which indicates that in the absence of systematics the Super-CLASS project could make a cosmic shear detection with radio data alone
Relationship between Interaction of Bending Stiffness of Component Yarns and the Structure of Fancy Bouclé and Semi-bouclé Yarns
No full textThis article investigates how the bending stiffness of the core thread and the effect threads affect the average values and the variability of the structural properties of resultant fancy yarns. The Design of Experiment technique was used to study the effects of individual factors and the interactions of factors. The analysis indicated that that the bending stiffness of the effect thread was a main factor. Increases in the effect thread bending stiffness led to significant increases of the size of fancy profile and reductions of the number of fancy profiles. Further, there was a strong interaction effect between the bending stiffness of the core thread and the bending stiffness of the effect thread that influenced the structures of the resultant fancy yarns. It was also found that variations in the bending stiffness of the input threads were reflected in similar variations in the size and number of fancy profiles. The study is important for engineering the structure and the variation in structural properties of fancy yarns by selecting appropriate input threads. <br/
Locating place in degrowth: Towards a spatially sensitive understanding of degrowth:American Association of Geographers Annual Meeting, Boston, USA
No full textIncidental lung cancers and positive CT images in HIV-infected individuals: results from the Copenhagen Co-morbidity in HIV Infection (COCOMO) Study
No full textLow dose computed tomography (LDCT) screening may not be feasible in people living with HIV as the prevalence of nodules may be particularly high. In the Copenhagen Comorbidity in HIV Infection (COCOMO) Study 901 LDCTs were performed. Two cases of lung cancer were identified, and a positive CT (non-calcified nodule ≥5mm or non-nodular lesions suggestive of malignancy) was found in 3.1% (9.7% of those at high risk for lung cancer, n=113). Invasive diagnostic procedures were rare and half of them led to a diagnosis of malignancy. These results are comparable to LDCT screening results from the general population
DESIGN AND MANUFACTURE OF INSTRUMENTED ROTOR BLADES FOR A HELICOPTER TEST RIG
No full textRotor blades have been designed, optimised, and manufactured for a national wind tunnel facility in the UK. The design included constraints such as blade diameter, to fit into existing wind tunnels, prescribed maximum centrifugal loads, and a unique fully articulated rotor head, capable of operating both as a conventional rotor and as a tilt-rotor. Two rotors having four instrumented blades each were finally produced. The rotors are mounted on a common rotor head on a rig, with or without rotorcraft fuselages. With the rotor head and hinges designed independently, important structural constraints were imposed on the overall blade design and aerodynamic loads. The Mach number scaled profiles were expected to generate 2.5 KN (at 2,500 rpm) and 3kN (at 3,000 rpm) of thrust for the helicopter and the tilt rotor blades, respectively. The maximum permissible radial hub load was 15kN. The embedded instrumentation was used to capture the blades vibration modes. The use of carbon fibre composites enabled a successful design and manufacturing of instrumented blades
