Estimation of mass thickness response of embedded aggregated silica nanospheres from high angle annular dark-field scanning transmission electron micrographs

In this study we investigate the functional behavior of the intensity in high-angle annular dark field (HAADF) scanning transmission electron micrograph (STEM) images. The model material is a silica particle (20 nm) gel at 5 wt%. By assuming that the intensity response is monotonically increasing with increasing mass thickness of silica, an estimate of the functional form is calculated using a maximum likelihood approach. We conclude that a linear functional form of the intensity provides a fair estimate but that a power function is significantly better for estimating the amount of silica in the z-direction. The work adds to the development of quantifying material properties from electron micrographs, especially in the field of tomography methods and three-dimensional quantitative structural characterization from a STEM micrograph. It also provides means for direct three-dimensional quantitative structural characterization from a STEM micrograph

Block bootstrap methods for the estimation of the intensity of a spatial point process with confidence bounds

This paper deals with the estimation of the intensity of a planar point process on the basis of a single point pattern, observed in a rectangular window. If the model assumptions of stationarity and isotropy hold, the method of block bootstrapping can be used to estimate the intensity of the process with confidence bounds. The results of two variants of block bootstrapping are compared with a parametric approximation based on the assumption of a Gaussian distribution of the numbers of points in deterministic subwindows of the original pattern. The studies were performed on patterns obtained by simulation of well-known point process models (Poisson process, two Matern cluster processes, Matern hardcore process, Strauss hardcore process). They were also performed on real histopathological data (point patterns of capillary profiles of 12 cases of prostatic cancer). The methods are presented as worked examples on two cases, where we illustrate their use as a check on stationarity (homogeneity) of a point process with respect to different fields of vision. The paper concludes with various methodological discussions and suggests possible extensions of the block bootstrap approach to other fields of spatial statistics

New insights on the behaviour of alternative types of individual-based tree models for natural forests

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The effect of spatial structure of forests on the precision and costs of plot-level forest resource estimation

Article no. 8201

Socioeconomic status is associated with process times in the emergency department for patients with chest pain

Abstract Objective Emergency department length of stay (EDLOS) is linked to crowding and patient outcomes whereas worse prognosis in low socioeconomic status remains poorly understood. We studied whether income was associated with ED process times among patients with chest pain. Methods This was a registry‐based cohort study on 124,980 patients arriving at 14 Swedish EDs between 2015 and 2019 with chest pain as their chief complaint. Individual‐level sociodemographic and clinical data were linked from multiple national registries. The associations between disposable income quintiles, whether the time to physician assessment exceeded triage priority recommendations as well as EDLOS were evaluated using crude and multivariable regression models adjusted for age, gender, sociodemographic variables, and ED‐management circumstances. Results Patients with the lowest income were more likely to be assessed by physician later than triage recommendations (crude odds ratio [OR] 1.25 (95% confidence interval [CI] 1.20–1.29) and have an EDLOS exceeding 6 h (crude OR 1.22 (95% CI 1.17–1.27). Among patients subsequently diagnosed with major adverse cardiac events, patients with the lowest income were more likely to be assessed by a physician later than triage recommendations, crude OR 1.19 (95% CI 1.02–1.40). In the fully adjusted model, the average EDLOS was 13 min (5.6%) longer among patients in the lowest income quintile, 4:11 [h:min], (95% CI 4:08–4:13), compared to patients in the highest income quintile, 3:58 (95% CI 3:56–4:00). Conclusions Among ED chest pain patients, low income was associated with longer time to physician than recommended by triage and longer EDLOS. Longer process times may have a negative impact due to crowding in the ED and delay diagnosis and timely treatment of the individual patient

Peri- and postoperative outcomes in patients with endometriosis undergoing hysterectomy

OBJECTIVES: To assess whether hysterectomy in patients with endometriosis is associated with higher proportion of complications compared with patients without, and whether route of hysterectomy affects this outcome. STUDY DESIGN: This is a population-based retrospective cohort study. Data were prospectively obtained from three National Swedish Registers. Patients undergoing a benign hysterectomy between 2015 and 2017 in Sweden were included in the study and were grouped according to a histology-proven diagnosis of endometriosis. Different hysterectomy modes were compared in patients with endometriosis. Perioperative data and postoperative complications up to 1 year after surgery were collected and measured. RESULTS: In all, 8,747 patients underwent a benign hysterectomy, and 1,166 patients with endometriosis was compared with 7,581 patients without. Patients with endometriosis had higher proportion of complications (adjusted Odds ratio aOR 1.2, 95% CI 1.0-1.4), were more often converted to abdominal hysterectomy (aOR 1.7, 95% CI 1.1-2.6), had higher estimated blood loss (EBL) (200-500 ml; aOR 1.8, 95% CI 1.4-2.3, \u3e500 ml; aOR 3.1, 95% CI 2.2-4.4) and a longer operative time (1-2 h; aOR 2.1, 95% CI 1.4-3.2, \u3e2 h; aOR 4.3, 95% CI 2.7-6.6) than endometriosis-free patients. The conversion rate was 13.8 times higher in total laparoscopic hysterectomy (TLH) compared with robotic-assisted laparoscopic hysterectomy (RATLH) (aOR 13.8, 95% CI 3.6-52.4). CONCLUSION: Higher conversion rate, higher EBL and higher frequency of complications were seen in patients with endometriosis. RATLH was associated with lower conversion rate compared to TLH

Characterization of pore structure of polymer blended films used for controlled drug release

The characterization of the pore structure in pharmaceutical coatings is crucial for understanding and controlling mass transport properties and function in controlled drug release. Since the drug release rate can be associated with the film permeability, the effect of the pore structure on the permeability is important to study. In this paper, a new approach for characterizing the pore structure in polymer blended films was developed based on an image processing procedure for given two-dimensional scanning electron microscopy images of film cross-sections. The focus was on different measures for characterizing the complexity of the shape of a pore. The pore characterization developed was applied to ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) blended films, often used as pharmaceutical coatings, where HPC acts as the pore former. It was studied how two different HPC viscosity grades influence the pore structure and, hence, mass transport through the respective films. The film with higher HPC viscosity grade had been observed to be more permeable than the other in a previous study; however, experiments had failed to show a difference between their pore structures. By instead characterizing the pore structures using tools from image analysis, statistically significant differences in pore area fraction and pore shape were identified. More specifically, it was found that the more permeable film with higher HPC viscosity grade seemed to have more extended and complex pore shapes than the film with lower HPC viscosity grade. This result indicates a greater degree of connectivity in the film with higher permeability and statistically confirms hypotheses on permeability from related experimental studies