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The most common detector material in the PC CT system, cannot achieve the best performance at a relatively higher photon flux rate. In the reconstruction view, the most commonly used filtered back projection, is not able to provide sufficient reconstructed image quality in spectral computed tomography (CT). Developing a triple-source saddle-curve cone-beam photon counting CT image reconstruction method can improve the temporal resolution. Triple-source saddle-curve cone-beam trajectory was rearranged into four trajectory sets for simulation and reconstruction. Projection images in different energy bins were simulated by forward projection and photon counting CT respond model simulation. After simulation, the object was reconstructed using Katsevich's theory after photon counts correction using the pseudo inverse of photon counting CT response matrix. The material decomposition can be performed based on images in different energy bins. Root mean square error (RMSE) and structural similarity index (SSIM) are calculated to quantify the image quality of reconstruction images. Compared with FDK images, the RMSE for the triple-source image was improved by 27%, 21%, 14%, 8%, and 6% for the reconstrued image of 20–33, 33–47, 47–58, 58–69, 69–80 keV energy bin. The SSIM was improved by 1.031%, 0.665%, 0.396%, 0.235%, 0.174% for corresponding energy bin. The decomposition image based on corrected images shows improved RMSE and SSIM, each by 33.861% and 0.345%. SSIM of corrected decomposition image of iodine reaches 99.415% of the original image. A new Triple-source saddle-curve cone-beam PC CT image reconstruction method was developed in this work. The exact reconstruction of the triple-source saddle-curve improved both the image quality and temporal resolution. [ABSTRACT FROM AUTHOR]

Glutamate acts at eight metabotropic glutamate (mGlu) receptor subtypes expressed in a partially overlapping fashion in distinct brain circuits. Recent evidence indicates that specific mGlu receptor protomers can heterodimerize and that these heterodimers can exhibit different pharmacology when compared to their homodimeric counterparts. Group III mGlu agonist-induced suppression of evoked excitatory potentials and induction of long-term potentiation at Schaffer collateral-CA1 (SC-CA1) synapses in the rodent hippocampus can be blocked by the selective mGlu7 negative allosteric modulator (NAM), ADX71743. Curiously, a different mGlu7 NAM, 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazo nolo[4,5-c]pyridin-4(5H)-one, failed to block these responses in brain slices despite its robust activity at mGlu7 homodimers in vitro. We hypothesized that this might result from heterodimerization of mGlu7 with another mGlu receptor protomer and focused on mGlu8 as a candidate given the reported effects of mGlu8-targeted compounds in the hippocampus. Here, we used complemented donor acceptor-resonance energy transfer to study mGlu7/8 heterodimer activation in vitro and observed that ADX71743 blocked responses of both mGlu7/7 homodimers and mGlu7/8 heterodimers, whereas 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazonolo[4,5-c]pyridin-4(5H)-one only antagonized responses of mGlu7/7 homodimers. Taken together with our electrophysiology observations, these results suggest that a receptor with pharmacology consistent with an mGlu7/8 heterodimer modulates the activity of SC-CA1 synapses. Building on this hypothesis, we identified two additional structurally related mGlu7 NAMs that also differ in their activity at mGlu7/8 heterodimers, in a manner consistent with their ability to inhibit synaptic transmission and plasticity at SC-CA1. Thus, we propose that mGlu7/8 heterodimers are a key molecular target for modulating the activity of hippocampal SC-CA1 synapses. [ABSTRACT FROM AUTHOR]

Current guidelines provide recommendation for transcatheter aortic-valve replacement (TAVR) in severe aortic stenosis without emphasis on valve systems. The comparative performances of balloon-expandable valves (BEV) and self-expanding valves (SEV) remain unclear. We aim to compare the early (30-day) and midterm (1-year) mortality and cardiovascular outcomes of BEV with SEV. PubMed, CENTRAL, and EMBASE were searched from inception to February 13, 2020 for randomized controlled trials (RCTs) and propensity-score matched (PSM) studies. Odds ratios (ORs) for binary outcomes and mean differences for continuous outcomes were pooled using random-effect models (DerSimonian–Laird method) with Hartung-Knapp-Sidik-Jonkman variance correction. Primary outcomes were early and midterm all-cause mortality. We included 3 RCTs (1418 patients) and 12 PSM studies (36,540 patients). Compared with SEV, BEV was associated with significantly lower mortality at 30 days (OR 0.76, 95% CI 0.67–0.85, p < 0.001, I2 = 0) and 1 year (OR 0.87, 95% CI 0.77–0.99, p = 0.04, I2 = 20.4%) in PSM studies, but not RCTs with insufficient power. Similar findings were found in subgroups analysis based on valve generations and SEV types. The 30-day and 1-year cardiovascular mortality, 30-day incidences of moderate to severe paravalvular leak, procedural contrast agent volume, and procedure time were lower, but transvalvular pressure gradient was higher in BEV than SEV in PSM studies. The 30-day incidences of permanent pacemaker implantation (PPI), acute kidney injury, stroke, major bleeding, major vascular complications, and rehospitalization were not statistically different between BEV and SEV. Early-generation SEV was associated with a higher 30-day PPI risk than corresponding BEV comparators. PPI risk was lower in ACURATE neo (Boston Scientific, Natick, MA) but higher in Evolut R SEV (Medtronic Inc., Minneapolis, MN), both compared with SAPIEN 3 BEV (Edwards Lifesciences, Irvine, CA). PSM studies suggest lower early and midterm mortality in BEV than SEV, but the contribution of unmeasured confounders cannot be excluded. Results from adequately powered RCTs with long-term follow-up are critically needed to confirm these findings. [Display omitted] • Balloon-expandable valve (BEV) transcatheter aortic-valve replacement might be associated with lower early and midterm total mortality than self-expanding valve (SEV) replacement. • Early moderate to severe paravalvular leak was lower with BEV than SEV. • Early incidence of stroke, permanent pacemaker implantation, acute kidney injury, and major bleeding were not different. [ABSTRACT FROM AUTHOR]

• Method for estimating time-dependent laser heat flux distribution. • Improvement of BPNN based on multiple population genetic algorithm. • Analysis of calculation efficiency and accuracy for different heat flux models. • Prediction of laser heat flux on the sample surface at different times. This study presents a method for estimating the time-dependent laser heat flux distribution of a nonlinear heat conduction system using a Back Propagation Neural Network improved by Multiple Population Genetic Algorithm (MPGA-BPNN) from transient temperature measurements. The primary focus of this research was on establishing a two-dimensional heat transfer model and training the MPGA-BPNN based on temperature distributions derived from finite volume simulations and any known heat flux. A series of numerical simulations were conducted to verify the feasibility of the proposed method, with corresponding experiments designed to test the method's efficacy. A comparative analysis was also conducted among BPNN, GA-BPNN and MPGA-BPNN methods. When the actual heat flux value is 4 × 105 W/m2, the relative errors for the BPNN, GA-BPNN, and MPGA-BPNN algorithms are 6.5%, 5.0%, and 1.0%, respectively. Furthermore, the MPGA-BPNN method has shown significant predictive capabilities in reliability and accuracy analyses across a range of cases. The study investigated the influence of network parameters and input temperatures on the heat flux outcomes using the MPGA-BPNN method. The heat flux of the laser on the sample surface was experimentally measured using this method, along with temperature distributions at 1.0–5.0 s obtained via a thermal imager. [ABSTRACT FROM AUTHOR]