27 research outputs found
Further evidence of tetragonality in bainitic ferrite
There is growing evidence that bainitic ferrite which retains a substantial amount of carbon in solid solution does not have cubic symmetry. We provide additional data on a different nanostructured bainitic steel to support this evidence, based on synchrotron X-ray diffraction experiments. The data are consistent only with a displacive transformation mechanism for bainite.We would like to thank Rolls-Royce plc and the Engineering and Physical
Sciences Research Council for their support during this project.This is the final version of the article. It first appeared from Maney Publishing via http://dx.doi.org/10.1179/1743284714Y.000000069
A scalable neural network architecture for self-supervised tomographic image reconstruction
We present a lightweight and scalable artificial neural network architecture which is used to reconstruct a tomographic image from a given sinogram. A self-supervised learning approach is used where the network iteratively generates an image that is then converted into a sinogram using the Radon transform; this new sinogram is then compared with the sinogram from the experimental dataset using a combined mean absolute error and structural similarity index measure loss function to update the weights of the network accordingly. We demonstrate that the network is able to reconstruct images that are larger than 1024 × 1024. Furthermore, it is shown that the new network is able to reconstruct images of higher quality than conventional reconstruction algorithms, such as the filtered back projection and iterative algorithms (SART, SIRT, CGLS), when sinograms with angular undersampling are used. The network is tested with simulated data as well as experimental synchrotron X-ray micro-tomography and X-ray diffraction computed tomography data
The Human Sweet Tooth
Humans love the taste of sugar and the word "sweet" is used to describe not only this basic taste quality but also something that is desirable or pleasurable, e.g., la dolce vita. Although sugar or sweetened foods are generally among the most preferred choices, not everyone likes sugar, especially at high concentrations. The focus of my group's research is to understand why some people have a sweet tooth and others do not. We have used genetic and molecular techniques in humans, rats, mice, cats and primates to understand the origins of sweet taste perception. Our studies demonstrate that there are two sweet receptor genes (TAS1R2 and TAS1R3), and alleles of one of the two genes predict the avidity with which some mammals drink sweet solutions. We also find a relationship between sweet and bitter perception. Children who are genetically more sensitive to bitter compounds report that very sweet solutions are more pleasant and they prefer sweet carbonated beverages more than milk, relative to less bitter-sensitive peers. Overall, people differ in their ability to perceive the basic tastes, and particular constellations of genes and experience may drive some people, but not others, toward a caries-inducing sweet diet. Future studies will be designed to understand how a genetic preference for sweet food and drink might contribute to the development of dental caries
Recommended from our members
Late Window Imaging Selection for Endovascular Therapy of Large Vessel Occlusion Stroke: An International Survey
Background
Current stroke guidelines recommend advanced imaging (computed tomography [CT] perfusion or magnetic resonance imaging) prior to endovascular therapy (EVT) in patients with late presentation of large vessel occlusion. Adherence to guidelines may be constrained by resources or timely access to imaging. We sought to understand the factors which influence late window imaging selection for EVT candidates with large vessel occlusion.
Methods
We conducted an international survey from January to May 2022. The questions aimed to identify advanced imaging and treatment decisions based on access to imaging, time delays, and simulated patient scenarios.
Results
There were 3000 invited participants and 1506 respondents, the majority (89.6%) from comprehensive stroke centers in high‐income countries. Neurointerventionalists comprised 31.8% and noninterventionalists 68.2% of respondents. Overall, 70.7% reported routine use of advanced imaging for late EVT selection, and 63.6% reported its usage in every case. There was greater availability of advanced imaging in comprehensive stroke centers versus primary stroke centers (67.0% versus 33.7%; P<0.0001), and high‐ versus low‐middle income countries (70.5% versus 44.5%; P<0.0001). When presented with a late window patient, 41.6% would complete CT perfusion or magnetic resonance imaging prior to EVT, 25.4% would perform CT perfusion or magnetic resonance imaging prior to IVT and EVT, and 25.8% would refer to EVT without advanced imaging. If advanced imaging was not readily available, 70.1% would refer a patient to EVT based on CT in the late window. Additional time delay within 20 minutes to obtain advanced imaging was considered acceptable in 77.7% of respondents.
Conclusion
Current guidelines for imaging late window EVT candidates are inconsistent with imaging decisions by physicians. Most respondents consider an imaging delay of greater than 20 minutes unacceptable. Access to advanced imaging was greater in comprehensive stroke centers and high‐income countries. In the case of limited access most respondents would consider EVT based on CT only
Recommended from our members
Research data supporting Experimental evidence for non-cubic bainitic ferrite
Data associated with syncrotron X-ray experiments conducted to show that the unit cell of bainitic ferrite is not cubi
nanoparticle precursors for chemical solution deposited electroceramic thin films
The Vascular Registry (VR) on carotid procedures collects long-term outcomes on carotid artery stenting (CAS) and carotid endarterectomy (CEA) patients. The purpose of this report is to describe in-hospital and 30-day CAS outcomes in patients with atherosclerotic carotid artery disease (CAD; atherosclerosis [ATH]) compared to recurrent carotid stenosis (RES) and radiation-induced stenosis (RAD).The VR collects provider-reported data on CAS using a Web-based data management system. For this report, data were analyzed at the preprocedure, procedure, predischarge, and 30-day intervals.As of November 20, 2008, there were 4017 patients with CAS with discharge data, of which 72% were due to ATH. A total of 2321 patients were available for 30-day outcomes analysis (1623 ATH, 529 restenosis, 119 radiation, 17 dissection, 3 trauma, and 30 other). Baseline demographics showed that ATH occurred in older patients (72-years-old), had the greatest history of coronary artery disease (CAD; 62%), myocardial infarction (MI; 24%), valvular heart disease (8%), arrhythmia (16%), congestive heart failure (CHF; 16%), diabetes mellitus (DM; 35%), and chronic obstructive pulmonary disease (COPD; 20%). RES had a higher degree of baseline stenosis (87.0 vs 85.8 ATH; P = .010), were less likely to be symptomatic (35.5% vs 46.3% ATH; P < .001), but had a greater history of hypertension, peripheral vascular disease (PVD), and smoking. RAD was seen in younger patients (66.6 vs 71.7 ATH; P < .001), were more likely to be male (78.2% vs 60.9% ATH; P < .001), and had less comorbidities overall, with the exception of amaurosis fugax, smoking, and cancer. The only statistically significant difference in perioperative rates was in transient ischemic attack (TIA; 2.7% ATH vs 0.9% RES; P = .02). There were no statistically significant differences in in-hospital death/stroke/MI (ATH 5.4%, RES 3.8%, RAD 4.2%) or at 30 days (ATH 7.1%, RES 5.1%, RAD 5.0%). Even after adjusting for age, gender, symptomatology, CHF, and renal failure, the only statistically significant difference at 30 days was amaurosis fugax between ATH and RAD (odds ratio [OR] 0.13; P = .01).Although patients with ATH have statistically significant comorbidities, they did not have statistically significant increased rates of death/stroke/MI during hospitalization or within 30 days after discharge when compared to RES or RAD. The CAS event rates for ATH vs RES and RAD are similar, despite prior published reports. Symptomatic ATH have statistically significant higher rates of death/stroke/MI compared to asymptomatic cohort. Finally, consistent and accurate entry of long-term data beyond initial hospitalization is essential to fully assess CAS outcomes since a significant number of adverse events occur in the interval from hospital discharge to 30 days
Recommended from our members
Synthesis and characterization of Pt(Cu0.67Sn0.33)
Pt(Cu0.67Sn0.33) has recently been found in a natural sample. In order to be able to characterize this new ternary compound, we synthesized it from the elements. Samples were characterized by X-ray powder diffraction, differential scanning calorimetry, thermal relaxation calorimetry, and scanning electron microscopy studies. Density functional theory-based model calculations complemented the experimental studies. Pt(Cu0.67Sn0.33) was already formed at a relatively low temperature of 773 K. Rietveld refinement of Pt(Cu0.67Sn0.33) has been carried out in CuAu-type or L10-type structure, space group P4∕mmm, with Pt on 0,0,0 and disordered Cu and Sn on [Formula presented], [Formula presented], [Formula presented] and Z = 1. The lattice parameters are a = 2.823(1) Å, c = 3.64(1) Å, and V = 29.00(4) Å 3; which are in good agreement with values obtained earlier on the natural sample and with the results of DFT calculations. The vibrational entropy for Pt(Cu0.67Sn0.33) is S298.15vib = 79.9(7) J mol−1 K−1. The pressure dependence up to 36(2) GPa of the unit-cell volume and the lattice parameters and unit-cell volume have been obtained by synchrotron based powder diffraction using a diamond anvil cell. A fit of a 3rd-order Birch–Murnaghan equation of state to the Pt(Cu0.67Sn0.33) (p,V)-data results in a bulk modulus of B0 = 215(27) GPa and B′ = 5(2)
Comparison of eight prehospital stroke scales to detect intracranial large-vessel occlusion in suspected stroke (PRESTO): a prospective observational study
Background: Due to the time-sensitive effect of endovascular treatment, rapid prehospital identification of large-vessel occlusion in individuals with suspected stroke is essential to optimise outcome. Interhospital transfers are an important cause of delay of endovascular treatment. Prehospital stroke scales have been proposed to select patients with large-vessel occlusion for direct transport to an endovascular-capable intervention centre. We aimed to prospectively validate eight prehospital stroke scales in the field. Methods: We did a multicentre, prospective, observational cohort study of adults with suspected stroke (aged ≥18 years) who were transported by ambulance to one of eight hospitals in southwest Netherlands. Suspected stroke was defined by a positive Face-Arm-Speech-Time (FAST) test. We included individuals with blood glucose of at least 2·5 mmol/L. People who presented more than 6 h after symptom onset were excluded from the analysis. After structured training, paramedics used a mobile app to assess items from eight prehospital stroke scales: Rapid Arterial oCclusion Evaluation (RACE), Los Angeles Motor Scale (LAMS), Cincinnati Stroke Triage Assessment Tool (C-STAT), Gaze-Face-Arm-Speech-Time (G-FAST), Prehospital Acute Stroke Severity (PASS), Cincinnati Prehospital Stroke Scale (CPSS), Conveniently-Grasped Field Assessment Stroke Triage (CG-FAST), and the FAST-PLUS (Face-Arm-Speech-Time plus severe arm or leg motor deficit) test. The primary outcome was the clinical diagnosis of ischaemic stroke with a proximal intracranial large-vessel occlusion in the anterior circulation (aLVO) on CT angiography. Baseline neuroimaging was centrally assessed by neuroradiologists to validate the true occlusion status. Prehospital stroke scale performance was expressed as the area under the receiver operating characteristic curve (AUC) and was compared with National Institutes of Health Stroke Scale (NIHSS) scores assessed by clinicians at the emergency department. This study was registered at the Netherlands Trial Register, NL7387. Findings: Between Aug 13, 2018, and Sept 2, 2019, 1039 people (median age 72 years [IQR 61–81]) with suspected stroke were identified by paramedics, of whom 120 (12%) were diagnosed with aLVO. Of all prehospital stroke scales, the AUC for RACE was highest (0·83, 95% CI 0·79–0·86), followed by the AUC for G-FAST (0·80, 0·76–0·84), CG-FAST (0·80, 0·76–0·84), LAMS (0·79, 0·75–0·83), CPSS (0·79, 0·75–0·83), PASS (0·76, 0·72–0·80), C-STAT (0·75, 0·71–0·80), and FAST-PLUS (0·72, 0·67–0·76). The NIHSS as assessed by a clinician in the emergency department did somewhat better than the prehospital stroke scales with an AUC of 0·86 (95% CI 0·83–0·89). Interpretation: Prehospital stroke scales detect aLVO with acceptable-to-good accuracy. RACE, G-FAST, and CG-FAST are the best performing prehospital stroke scales out of the eight scales tested and approach the performance of the clinician-assessed NIHSS. Further studies are needed to investigate whether use of these scales in regional transportation strategies can optimise outcomes of patients with ischaemic stroke. Funding: BeterKeten Collaboration and Theia Foundation (Zilveren Kruis)