Mixed-polarity random-dot stereograms alter GABA and Glx concentration in the early visual cortex.

The offset between images projected onto the left and right retina (binocular disparity) provides a powerful cue to the three-dimensional structure of the environment. It was previously shown that depth judgements are better when images comprise both light and dark features, rather than only light or only dark elements. Since Harris and Parker (Nature 374: 808-811, 1995) discovered the "mixed-polarity benefit," there has been limited evidence supporting their hypothesis that the benefit is due to separate bright and dark channels. Goncalves and Welchman (Curr Biol 27: 1403-1412, 2017) observed that single- and mixed-polarity stereograms evoke different levels of positive and negative activity in a deep neural network trained on natural images to make depth judgements, which also showed the mixed-polarity benefit. Motivated by this discovery, we seek to test the potential for changes in the balance of excitation and inhibition that are produced by viewing these stimuli. In particular, we use magnetic resonance spectroscopy to measure Glx and GABA concentrations in the early visual cortex of adult humans during viewing of single- and mixed-polarity random-dot stereograms (RDS). We find that participants' Glx concentration is significantly higher, whereas GABA concentration is significantly lower, when mixed-polarity RDS are viewed than when single-polarity RDS are viewed. These results indicate that excitation and inhibition facilitate processing of single- and mixed-polarity stereograms in the early visual cortex to different extents, consistent with recent theoretical work (Goncalves NR, Welchman AE. Curr Biol 27: 1403-1412, 2017).NEW & NOTEWORTHY Depth judgements are better when images comprise both light and dark features, rather than only light or only dark elements. Using magnetic resonance spectroscopy, we show that adult human participants' Glx concentration is significantly higher whereas GABA concentration is significantly lower in the early visual cortex when participants view mixed-polarity random-dot stereograms (RDS) compared with single-polarity RDS. These results indicate that excitation and inhibition facilitate processing of single- and mixed-polarity stereograms in the early visual cortex to different extents.This work was supported by the Leverhulme Trust (ECF-2017-573), the Issac Newton Trust (17.08(o)), and the Wellcome Trust (095183/Z/10/Z)

7 tesla FMRI reveals systematic functional organization for binocular disparity in dorsal visual cortex.

The binocular disparity between the views of the world registered by the left and right eyes provides a powerful signal about the depth structure of the environment. Despite increasing knowledge of the cortical areas that process disparity from animal models, comparatively little is known about the local architecture of stereoscopic processing in the human brain. Here, we take advantage of the high spatial specificity and image contrast offered by 7 tesla fMRI to test for systematic organization of disparity representations in the human brain. Participants viewed random dot stereogram stimuli depicting different depth positions while we recorded fMRI responses from dorsomedial visual cortex. We repeated measurements across three separate imaging sessions. Using a series of computational modeling approaches, we report three main advances in understanding disparity organization in the human brain. First, we show that disparity preferences are clustered and that this organization persists across imaging sessions, particularly in area V3A. Second, we observe differences between the local distribution of voxel responses in early and dorsomedial visual areas, suggesting different cortical organization. Third, using modeling of voxel responses, we show that higher dorsal areas (V3A, V3B/KO) have properties that are characteristic of human depth judgments: a simple model that uses tuning parameters estimated from fMRI data captures known variations in human psychophysical performance. Together, these findings indicate that human dorsal visual cortex contains selective cortical structures for disparity that may support the neural computations that underlie depth perception.This work wassupported by the European Community’s Seventh Framework Programme FP7/2007-2013 (Grant PITN-GA- 2011-290011), the Japan Society for the Promotion of Science (JSPS KAKENHI Grant 26870911), and the Wellcome Trust (Grant 095183/Z/10/Z).This is the final version of the article. It was originally published in the Journal of Neuroscience, 18 February 2015, 35(7): 3056-3072; doi: 10.1523/JNEUROSCI.3047-14.2015

Sutureless bioprosthesis for aortic valve replacement: surgical and clinical outcomes

© 2022 The Authors. Journal of Cardiac Surgery published by Wiley Periodicals LLC. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.Background: Aortic valve stenosis is the most common adult valve disease in industrialized countries. The aging population and the increase in comorbidities urge the development of safer alternatives to the current surgical treatment. Sutureless bioprosthesis has shown promising results, especially in complex procedures and in patients requiring concomitant surgeries. Objectives: Assess the clinical and hemodynamic performance, safety, and durability of the Perceval® prosthetic valve. Methods: This single-center retrospective longitudinal cohort study collected data from all adult patients with aortic valve disease who underwent aortic valve replacement with a Perceval® prosthetic valve between February 2015 and October 2020. Of the 196 patients included (mean age 77.20 ± 5.08 years; 45.4% female; mean EuroSCORE II 2.91 ± 2.20%), the majority had aortic stenosis. Results: Overall mean cross-clamp and cardiopulmonary bypass times were 33.31 ± 14.09 min and 45.55 ± 19.04 min, respectively. Mean intensive care unit and hospital stay were 3.32 ± 3.24 days and 7.70 ± 5.82 days, respectively. Procedural success was 98.99%, as two explants occurred. Four valves were reimplanted due to intraoperative misplacement. Mean transvalvular gradients were 7.82 ± 3.62 mmHg. Pacemaker implantation occurred in 12.8% of patients, new-onset atrial fibrillation in 21.9% and renal replacement support was necessary for 3.1%. Early mortality was 2.0%. We report no structural valve deterioration, strokes, or endocarditis, and one successfully treated valve thrombosis. Conclusions: Our study confirms the excellent clinical and hemodynamic performance and safety of a truly sutureless aortic valve, up to a 5-year follow-up. These results were consistent in isolated and concomitant interventions, solidifying this device as a viable option for the treatment of isolated aortic valve disease.info:eu-repo/semantics/publishedVersio

Application of single molecule technology to rapidly map long DNA and study the conformation of stretched DNA

Herein we describe the first application of direct linear analysis (DLA) to the mapping of a bacterial artificial chromosome (BAC), specifically the 185.1 kb-long BAC 12M9. DLA is a single molecule mapping technology, based on microfluidic elongation and interrogation of individual DNA molecules, sequence-specifically tagged with bisPNAs. A DNA map with S/N ratio sufficiently high to detect all major binding sites was obtained using only 200 molecule traces. A new method was developed to extract an oriented map from an averaged map that included a mixture of head-first and tail-first DNA traces. In addition, we applied DLA to study the conformation and tagging of highly stretched DNA. Optimal conditions for promoting sequence-specific binding of bisPNA to an 8 bp target site were elucidated using DLA, which proved superior to electromobility shift assays. DLA was highly reproducible with a hybridized tag position localized with an accuracy of ±0.7 µm or ±2.1 kb demonstrating its utility for rapid mapping of large DNA at the single molecule level. Within this accuracy, DNA molecules, stretched to at least 85% of their contour length, were stretched uniformly, so that the map expressed in relative coordinates, was the same regardless of the molecule extension

Development and validation of a novel fibre-optic respiratory rate sensor (FiRRS) integrated in oxygen delivery devices

© 2021 The Author(s). Respiratory rate (RR) monitoring provides crucial information on the overall health condition of patients and a reliable, low cost RR monitor for normal hospital inpatient or home use would be of significant benefit. The proposed system measures light reflection from a Fibre Bragg Grating (FBG) located near, and the total reflection spectrum from a humidity sensing film deposited at, the tip of an optical fibre. Every breath causes a shift in the wavelength reflected from the FBG and intensity change in the overall reflection spectrum. The accuracy of different techniques is investigated in a two-part study with 15 healthy volunteers. In part 1, the participants' respiration rate followed a handheld mobile application at 5, 12 and 30 breaths per minute with simultaneous measurement using the optical fibre system, thoracic impedance pneumography (TIP) and capnometry device (where possible). Two types of medical face masks and a nasal cannula with oxygen delivery rates were investigated. In part 2, participants wore an anaesthetic face mask and breathed at normal and low tidal volumes to evaluate whether low tidal volumes could be detected. The most accurate measurement of RR was through monitoring the Bragg wavelength shift (mean accuracy = 88.1%), followed by the intensity change at the Bragg wavelength (mean accuracy = 78.9%), capnometry (mean accuracy = 77.8%), area under the overall spectrum (mean accuracy = 65.4%) and TIP (mean accuracy = 43.1%). The Fibre-optic Respiratory Rate Sensor system (FiRRS) can differentiate between normal and low tidal volumes (p-value < 0.05) and demonstrated higher accuracy than capnometry measurement of end-tidal carbon dioxide in exhaled air. These latter two monitors measured RR more accurately than TIP. A comparable accuracy in the measurement of RR was obtained when the FiRRS was implemented in nasal cannula and face masks

Study of Tau-pair Production in Photon-Photon Collisions at LEP and Limits on the Anomalous Electromagnetic Moments of the Tau Lepton

Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb^{-1}. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.Comment: 20 pages, 9 figures, Accepted by Eur. Phys. J.

CP asymmetry in B→ϕKSB \to \phi K_S in a general two-Higgs-doublet model with fourth-generation quarks

We discuss the time-dependent CP asymmetry of decay $B \to \phi K_S$ in an extension of the Standard Model with both two Higgs doublets and additional fourth-generation quarks. We show that although the Standard Model with two-Higgs-doublet and the Standard model with fourth generation quarks alone are not likely to largely change the effective $\sin 2 \beta$ from the decay of $B \to \phi K_S$, the model with both additional Higgs doublet and fourth-generation quarks can easily account for the possible large negative value of $\sin 2 \beta$ without conflicting with other experimental constraints. In this model, additional large CP violating effects may arise from the flavor changing Yukawa interactions between neutral Higgs bosons and the heavy fourth generation down type quark, which can modify the QCD penguin contributions. With the constraints obtained from $b \to s \bar{s} s$ processes such as $B \to X_s \gamma$ and $\Delta m_{B_s^0}$, this model can lead to the effective $\sin 2 \beta$ to be as large as $- 0.4$ in the CP asymmetry of $B \to \phi K_S$.Comment: 13 pages, 5 figures, references added, to appear in Eur.Phys.J.

Energy dependence of Cronin momentum in saturation model for p+Ap+A and A+AA+A collisions

We calculate $\sqrt{s}$ dependence of Cronin momentum for $p+A$ and $A+A$ collisions in saturation model. We show that this dependence is consistent with expectation from formula which was obtained using simple dimentional consideration. This can be used to test validity of saturation model (and distinguish among its variants) and measure $x$ dependence of saturation momentum from experimental data.Comment: LaTeX2e, 12 pages, 8 figure

A Precise Measurement of the Tau Lifetime

The tau lepton lifetime has been measured with the e+e- -> tau+tau- events collected by the DELPHI detector at LEP in the years 1991-1995. Three different methods have been exploited, using both one-prong and three-prong tau decay channels. Two measurements have been made using events in which both taus decay to a single charged particle. Combining these measurements gave tau_tau (1 prong) = 291.8 +/- 2.3 (stat) +/- 1.5 (sys) fs. A third measurement using taus which decayed to three charged particles yielded tau_tau (3 prong) = 288.6 +/- 2.4 (stat) +/- 1.3 (sys) fs. These were combined with previous DELPHI results to measure the tau lifetime, using the full LEP1 data sample, to be tau_tau = 290.9 +/- 1.4 (stat) +/- 1.0 (sys) fs.Comment: 27 pages, 7 figure