714 research outputs found
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Under-sampling and compressed sensing of 3D spatially-resolved displacement propagators in porous media using APGSTE-RARE MRI.
A method for under-sampling and compressed sensing of 3D spatially-resolved propagators is presented and demonstrated for flow in a packed bed and a heterogeneous carbonate rock. By sampling only 12.5% of q,k-space, the experimental acquisition time was reduced by almost an order of magnitude. In particular, for both systems studied, a 3D image was acquired at 1 mm isotropic spatial resolution such that 134,400 local propagators were obtained. Data were acquired in ~1 h and ~11 h for the packed bed and rock, respectively. It is shown that spatial resolution and under-sampling using this implementation retains the quantitative nature of the propagator measurement, and differences between implementation of this measurement in two and three dimensions are identified. The potential for 3D spatially-resolved propagators to provide new insights into transport processes in porous media by characterisation of the statistical moments of the propagators is discussed
Morphology, activity area, and movement patterns of the frugivorous monitor lizard Varanus Bitatawa
The newly described Varanus bitatawa is a large, frugivorous, monitor lizard endemic to the northern Sierra Madre mountain range in Luzon, Philippines. This study presents the first description of its ecology from tracking and camera trapping. We captured five adult lizards weighing 1.0-5.1 kg with snout-vent lengths (SVL) from 40-66 cm and total lengths from 100-164 cm. Activity areas were non-overlapping with a mean of 12,400 m(2); males (23,300 m(2)) had larger activity areas than females (5,200 m(2)). Capture and camera trap records indicate that lizards move most frequently between 1000 and 1500. Movements were characterized by straight line distances between trees with a mean distance travelled between trees of 79 m. Mean daily distance covered was 176 m with larger distances covered by males (228 m vs 142 m for females).Environmental BiologyConservation Biolog
Very long-term follow-up of Indiana Pouches proves durability
Introduction: An Indiana Pouch (IP) is a heterotopic, continent, urinary diversion from an ileocolonic segment. Numerous studies have investigated its long-term outcomes, albeit none extending beyond a 5-year follow-up period. IPs can be used as urinary diversion for benign indications and as such are constructed in typically young patients. As a consequence of their extended lifespan, there is a need for very long-term (>5 years) IP outcome data and comprehensive complication analysis. Materials and Methods: In this retrospective cohort study, the data of all patients attending our academic functional urology tertiary referral center for surveillance between 2015 and 2022 after an earlier IP procedure without uro-oncological indication were analyzed. The primary objective was to identify the prevalence of complications associated with IP, including stomal stenosis, ureter-pouch stenosis, pouch calculi, stomal leakage, pouch perforation, and parastomal herniation, and to determine the time span between creation of the IP and occurrence of complications. Results: A cohort of 33 patients (23 female) was analyzed. Median age at IP creation was 38 (range 5–62) years. Median follow-up was 258 (range 24–452) months. During follow-up, 22 (67%) patients underwent at least one surgical revision. In total, 45 revision procedures were performed. The estimated mean revision-free survival was 198 (95%-CI 144–242) months. Conclusion: Two-thirds of our IP patients required surgical revision during very long-term follow-up. However, the mean revision-free survival was 198 months. This establishes the IP as a durable and resilient option for urinary diversion, yet underlines the need for lifelong follow-up as some of these complications and indication were subclinical. These results contribute significantly to patient counseling when discussing different options for urinary diversion, especially at a younger age
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Acquisition of spatially-resolved displacement propagators using compressed sensing APGSTE-RARE MRI.
A method is presented for accelerating the acquisition of spatially-resolved displacement propagators via under-sampling of an Alternating Pulsed Gradient Stimulated Echo - Rapid Acquisition with Relaxation Enhancement (APGSTE-RARE) data acquisition with compressed sensing image reconstruction. The method was demonstrated with respect to the acquisition of 2D spatially-resolved displacement propagators of water flowing through a packed bed of hollow cylinders. The q,k-space was under-sampled according to variable-density pseudo-random sampling patterns. The quality of compressed sensing reconstructions of spatially-resolved propagators at a range of sampling fractions was assessed using the peak signal-to-noise ratio (PSNR) as a quality metric. Propagators of good quality (PSNR 33.2 dB) were reconstructed from only 6.25% of all data points in q,k-space, resulting in a reduction in the data acquisition time from 4 h to 14 min. The spatially-resolved propagators were reconstructed using both the total variation and nuclear norm sparsifying transforms; use of total variation resulted in a slightly higher quality of the reconstructed image in most cases. To illustrate the power of this method to characterise heterogeneous flow in porous media, the method is applied to the characterisation of flow in a vuggy carbonate rock
Record RF performance of standard 90 nm CMOS technology
We have optimized 3 key RF devices realized in standard logic 90 nm CMOS technology and report a record performance in terms of n-MOS maximum oscillation frequency f/sub max/ (280 GHz), varactor tuning range and varactor and inductor quality factor
Drug repurposing for rare:progress and opportunities for the rare disease community
Repurposing is one of the key opportunities to address the unmet rare diseases therapeutic need. Based on cases of drug repurposing in small population conditions, and previous work in drug repurposing, we analyzed the most important lessons learned, such as the sharing of clinical observations, reaching out to regulatory scientific advice at an early stage, and public-private collaboration. In addition, current upcoming trends in the field of drug repurposing in rare diseases were analyzed, including the role these trends could play in the rare diseases’ ecosystem. Specifically, we cover the opportunities of innovation platforms, the use of real-world data, the use of artificial intelligence, regulatory initiatives in repurposing, and patient engagement throughout the repurposing project. The outcomes from these emerging activities will help progress the field of drug repurposing for the benefit of patients, public health and medicines development
Prediction of Cognitive Recovery after Stroke:The Value of Diffusion-Weighted Imaging–Based Measures of Brain Connectivity
Background and Purpose: Prediction of long-term recovery of a poststroke cognitive disorder (PSCD) is currently inaccurate. We assessed whether diffusion-weighted imaging (DWI)–based measures of brain connectivity predict cognitive recovery 1 year after stroke in patients with PSCD in addition to conventional clinical, neuropsychological, and imaging variables. Methods: This prospective monocenter cohort study included 217 consecutive patients with a clinical diagnosis of ischemic stroke, aged ≥50 years, and Montreal Cognitive Assessment score below 26 during hospitalization. Five weeks after stroke, patients underwent DWI magnetic resonance imaging. Neuropsychological assessment was performed 5 weeks and 1 year after stroke and was used to classify PSCD as absent, modest, or marked. Cognitive recovery was operationalized as a shift to a better PSCD category over time. We evaluated 4 DWI-based measures of brain connectivity: global network efficiency and mean connectivity strength, both weighted for mean diffusivity and fractional anisotropy. Conventional predictors were age, sex, level of education, clinical stroke characteristics, neuropsychological variables, and magnetic resonance imaging findings (eg, infarct size). DWI-based measures of brain connectivity were added to a multivariable model to assess additive predictive value. Results: Of 135 patients (mean age, 71 years; 95 men [70%]) with PSCD 5 weeks after ischemic stroke, 41 (30%) showed cognitive recovery. Three of 4 brain connectivity measures met the predefined threshold of P<0.1 in univariable regression analysis. There was no added value of these measures to a multivariable model that included level of education and infarct size as significant predictors of cognitive recovery. Conclusions: Current DWI-based measures of brain connectivity appear to predict recovery of PSCD but at present have no added value over conventional predictors
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