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Tomography ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 10-21
Author(s):  
Brendan Lee Eck ◽  
Kecheng Liu ◽  
Wei-ching Lo ◽  
Yun Jiang ◽  
Vikas Gulani ◽  
...  

The purpose of this work is to evaluate the feasibility of performing magnetic resonance fingerprinting (MRF) on older and lower-performance MRI hardware as a means to bring advanced imaging to the aging MRI install base. Phantom and in vivo experiments were performed on a 1.5T Siemens Aera (installed 2015) and 1.5T Siemens Symphony (installed 2002). A 2D spiral MRF sequence for simultaneous T1/T2/M0 mapping was implemented on both scanners with different gradient trajectories to accommodate system specifications. In phantom, for T1/T2 values in a physiologically relevant range (T1: 195–1539 ms; T2: 20–267 ms), scanners had strong correlation (R2 > 0.999) with average absolute percent difference of 8.1% and 10.1%, respectively. Comparison of the two trajectories on the newer scanner showed differences of 2.6% (T1) and 10.9% (T2), suggesting a partial explanation of the observed inter-scanner bias. Inter-scanner agreement was better when the same trajectory was used, with differences of 6.0% (T1) and 4.0% (T2). Intra-scanner coefficient of variation (CV) of T1 and T2 estimates in phantom were <2.0% and in vivo were ≤3.5%. In vivo inter-scanner white matter CV was 4.8% (T1) and 5.1% (T2). White matter measurements on the aging scanner after two months were consistent, with differences of 1.9% (T1) and 3.9% (T2). In conclusion, MRF is feasible on an aging MRI scanner and required only changes to the gradient trajectory.


2021 ◽  
pp. 147488512110626
Author(s):  
Andrei Poama ◽  
Alexandru Volacu

Are there any prima facie reasons that democracies might have for disenfranchising older citizens? This question reflects increasingly salient, but often incompletely theorized complaints that members of democratic publics advance about older citizens’ electoral influence. Rather than rejecting these complaints out of hand, we explore whether, suitably reconstructed, they withstand democratic scrutiny. More specifically, we examine whether the account of political equality that seems to most fittingly capture the logic of these complaints – namely, equal opportunity of political influence over electoral outcomes – can justify disenfranchising older citizens. We conclude that equal opportunity of influence cannot ground a blanket disenfranchisement of older people and that, taken in conjunction with other general considerations that apply to all sound electoral policies, partial disenfranchisement proposals (i.e. proposals for reducing the electoral influence of older citizens via age-weighted voting) are both quasi-inapplicable and practically unrobust across a relevant range of political contexts.


2021 ◽  
Author(s):  
Rachel Lim ◽  
Hoi Lok Cheng ◽  
Jia Huan ◽  
Patthara Kongsuphol ◽  
Bhuvaneshwari D/O Shunmuganath ◽  
...  

There is clinical need for a quantifiable point-of-care (PoC) SARS-CoV-2 neutralizing antibody (nAb) test that is adaptable with the pandemics changing landscape. Here, we present a rapid and semi-quantitative nAb test that uses finger stick or venous blood to assess the nAb response of vaccinated population against wild-type, alpha, beta, gamma, and delta variant receptor binding domains. It captures a clinically relevant range of nAb levels, and effectively differentiates pre-vaccination, post 1st dose and post 2nd dose vaccination samples within 10 minutes. The data observed against alpha, beta, gamma, and delta variants agrees with published results evaluated in established serology tests. Finally, our test revealed a substantial reduction in nAb level for beta, gamma, and delta variants between early BNT162b2 vaccination group (within 3 months) and later vaccination group (post 3 months). This test is highly suited for PoC settings and provides an insightful nAb response in a post-vaccinated population.


2021 ◽  
Author(s):  
Matthew Smith ◽  
Daniel Sievenpiper

<p>· We propose multi-loci and multi-site current patterning (sequential or simultaneous) for precise, rapid and repeatable steering for improved neuronal targeting.</p><p>· Here we demonstrate these improvements by using a unique pixel cell for excitation synthesis as enabled by a three-layer dense magnetic coil array that is mapped to a hexagonal grid with cubic coordinates.</p><p>· We validate the theory with supporting simulations, experimental results and a scalable electronics design that can address a relevant range of larger coil diameters, higher power levels and topologies.</p><p><a></a></p><p>· Precise, rapid and repeatable patterns potentially offer new modalities for noninvasive neuromodulation (suprathreshold and subthreshold) and adjacent biomagnetic applications such as tumor cell membrane disruption [1], and magnetic drug delivery [2].</p>


2021 ◽  
Author(s):  
Matthew Smith ◽  
Daniel Sievenpiper

<p>· We propose multi-loci and multi-site current patterning (sequential or simultaneous) for precise, rapid and repeatable steering for improved neuronal targeting.</p><p>· Here we demonstrate these improvements by using a unique pixel cell for excitation synthesis as enabled by a three-layer dense magnetic coil array that is mapped to a hexagonal grid with cubic coordinates.</p><p>· We validate the theory with supporting simulations, experimental results and a scalable electronics design that can address a relevant range of larger coil diameters, higher power levels and topologies.</p><p><a></a></p><p>· Precise, rapid and repeatable patterns potentially offer new modalities for noninvasive neuromodulation (suprathreshold and subthreshold) and adjacent biomagnetic applications such as tumor cell membrane disruption [1], and magnetic drug delivery [2].</p>


Author(s):  
Ann Corsellis

There is a pressing need to provide a worthwhile academic underpinning to public service or community interpreting and its professional context. This paper considers the strategies that could benefit both pure and applied research in this area by discussing a number of majorfactors. First, the approaches used by interpreting as well as related scientific re- search in the public service field to engage with the relevant range of professional practitioners in identifying the topic, gathering adequate and reliable information, seeking ways forward, developing interdisciplinary understanding and implementing improvedpractice, are considered.Second, it is argued that there is a crucial needfor interpreting and language specialists to demonstrate and apply standards of valid research methodologies equivalent to those used in other disciplines in this context (such as medicine), in order to affirm their academic responsibility and interdisciplinary credibility. Finally, the dissemination of the results of research, not only to fellow academics in the language world but also to academics in other related disciplines as well as to the practitioners - interpreters, translators, doctors, lawyers, police officers, social workers etc., is considered. Research results must be accessible in order to improve practice and to enable the research results to be brought into the mainstream informed debate.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1524
Author(s):  
Saquib Ahmed M. A. Peerzade ◽  
Nadezhda Makarova ◽  
Igor Sokolov

The mesoporous nature of silica nanoparticles provides a novel platform for the development of ultrabright fluorescent particles, which have organic molecular fluorescent dyes physically encapsulated inside the silica pores. The close proximity of the dye molecules, which is possible without fluorescence quenching, gives an advantage of building sensors using FRET coupling between the encapsulated dye molecules. Here we present the use of this approach to demonstrate the assembly of ultrabright fluorescent ratiometric sensors capable of simultaneous acidity (pH) and temperature measurements. FRET pairs of the temperature-responsive, pH-sensitive and reference dyes are physically encapsulated inside the silica matrix of ~50 nm particles. We demonstrate that the particles can be used to measure both the temperature in the biologically relevant range (20 to 50 °C) and pH within 4 to 7 range with the error (mean absolute deviation) of 0.54 °C and 0.09, respectively. Stability of the sensor is demonstrated. The sensitivity of the sensor ranges within 0.2–3% °C−1 for the measurements of temperature and 2–6% pH−1 for acidity.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. Pablo Bonilla Ataides ◽  
David K. Tuckett ◽  
Stephen D. Bartlett ◽  
Steven T. Flammia ◽  
Benjamin J. Brown

AbstractPerforming large calculations with a quantum computer will likely require a fault-tolerant architecture based on quantum error-correcting codes. The challenge is to design practical quantum error-correcting codes that perform well against realistic noise using modest resources. Here we show that a variant of the surface code—the XZZX code—offers remarkable performance for fault-tolerant quantum computation. The error threshold of this code matches what can be achieved with random codes (hashing) for every single-qubit Pauli noise channel; it is the first explicit code shown to have this universal property. We present numerical evidence that the threshold even exceeds this hashing bound for an experimentally relevant range of noise parameters. Focusing on the common situation where qubit dephasing is the dominant noise, we show that this code has a practical, high-performance decoder and surpasses all previously known thresholds in the realistic setting where syndrome measurements are unreliable. We go on to demonstrate the favourable sub-threshold resource scaling that can be obtained by specialising a code to exploit structure in the noise. We show that it is possible to maintain all of these advantages when we perform fault-tolerant quantum computation.


2021 ◽  
Vol 19 (1) ◽  
pp. 039
Author(s):  
Fabian Forsbach ◽  
Markus Heß

In the electroadhesive frictional contact of a sliding fingerpad on a touchscreen, friction is enhanced by an induced electroadhesive force. This force is dominated by the frequency-dependent impedance behavior of the relevant electrical layers. However, many existing models are only valid at frequency extremes and use very simplified contact mechanical approaches. In the present paper, a RC impedance model is adopted to characterize the behavior in the relevant range of frequencies of the AC excitation voltage. It serves as an extension to the macroscopic model for electrovibration recently developed by the authors, which is based on several well-founded approaches from contact mechanics. The predictions of the extended model are compared to recent experimental results and the most influential electrical and mechanical parameters are identified and discussed. Finally, the time responses to different wave forms of the excitation voltage are presented.


2021 ◽  
Author(s):  
Renan Belli ◽  
Katrin Hurle ◽  
Jana Schürrlein ◽  
Anselm Petschelt ◽  
Katharina Werbach ◽  
...  

<p>The relationship between fracture toughness and Yttria content in modern zirconia ceramics was revised. For that purpose, we evaluated here 10 modern Y<sub>2</sub>O<sub>3</sub>-stabilized zirconia (YSZ) materials currently used in biomedical applications, namely prosthetic and implant dentistry. The most relevant range between 2-5 mol% Y<sub>2</sub>O<sub>3</sub> was addressed by selecting from conventional opaque 3 mol% YSZ up to more translucent compositions (4-5 mol% YSZs). A technical 2YSZ was used to extend the range of our evaluation. The bulk mol% Y<sub>2</sub>O<sub>3</sub> concentration was measured by X-Ray Fluorescence Spectroscopy. Phase quantification by Rietveld refinement are supplied by considering only two tetragonal phases or an additional improbable cubic phase. A first-account of the fracture toughness (<i>K</i><sub>Ic</sub>) of the partly-sintered materials is given, which amounted to 0.4 – 0.7 MPaÖm. In the fully-densified state, an inverse power-law behavior was obtained between <i>K</i><sub>Ic</sub> and bulk mol% Y<sub>2</sub>O<sub>3</sub> content, whether using only our measurements or including literature data, challenging some established relationships.</p>


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