51 research outputs found
Vectorial characterization of Bloch surface wave via one-dimensional photonic-atomic structure
Use of hot atomic vapor as a new tool for tracing the complex nature of light
has become a knowledge-based topic in recent years. In this paper, we examine
the polarization ellipse of the Bloch surface wave (BSW) through the effect of
a magnetic field on the coupling of these surface waves in BSW-hot atomic vapor
cell. For this purpose, we fabricate a one-dimensional photonic crystal-based
Bloch wave atom cell, where under different configurations of magnetic field,
polarization ellipse of Bloch surface waves has been recorded experimentally.
Our results indicate that by applying the magnetic field in different
directions, Faraday and Voigt, the characteristics of electromagnetically
induced transparency (EIT-like) of hybrid system change. We have used these
changes to redefine the geometry of Voigt and Faraday for evanescent waves, as
well as to measure the ratio of the components of the elliptical polarized
electric field. These characterizations can open new insight into the
miniaturized atomic field in high quality and low volumetric areas
The image biomarker standardization initiative: Standardized convolutional filters for reproducible radiomics and enhanced clinical insights
Standardizing convolutional filters that enhance specific structures and patterns in medical imaging enables reproducible radiomics analyses, improving consistency and reliability for enhanced clinical insights.
Filters are commonly used to enhance specific structures and patterns in images, such as vessels or peritumoral regions, to enable clinical insights beyond the visible image using radiomics. However, their lack of standardization restricts reproducibility and clinical translation of radiomics decision support tools. In this special report, teams of researchers who developed radiomics software participated in a three-phase study (September 2020 to December 2022) to establish a standardized set of filters. The first two phases focused on finding reference filtered images and reference feature values for commonly used convolutional filters: mean, Laplacian of Gaussian, Laws and Gabor kernels, separable and nonseparable wavelets (including decomposed forms), and Riesz transformations. In the first phase, 15 teams used digital phantoms to establish 33 reference filtered images of 36 filter configurations. In phase 2, 11 teams used a chest CT image to derive reference values for 323 of 396 features computed from filtered images using 22 filter and image processing configurations. Reference filtered images and feature values for Riesz transformations were not established. Reproducibility of standardized convolutional filters was validated on a public data set of multimodal imaging (CT, fluorodeoxyglucose PET, and T1-weighted MRI) in 51 patients with soft-tissue sarcoma. At validation, reproducibility of 486 features computed from filtered images using nine configurations × three imaging modalities was assessed using the lower bounds of 95% CIs of intraclass correlation coefficients. Out of 486 features, 458 were found to be reproducible across nine teams with lower bounds of 95% CIs of intraclass correlation coefficients greater than 0.75. In conclusion, eight filter types were standardized with reference filtered images and reference feature values for verifying and calibrating radiomics software packages. A web-based tool is available for compliance checking
Clinical and histological characterization of oral pemphigus lesions in patients with skin diseases: a cross sectional study from Sudan
Numerical Analysis of Laminar Flow around Square Cylinders with EHD Phenomenon
In this research, a numerical simulation of an Electrohydrodynamic (EHD) actuator’s effects on the flow around a square cylinder by using a finite volume method has been investigated. This is one of the newest ways for controlling the fluid flows. Two plate electrodes are flush-mounted on the surface of the cylinder and one wire electrode is placed on the line with zero angle of attack relative to the stagnation point and excited with DC power supply. The discharge produces an electric force and changes the local momentum behaviors in the fluid layers. For this purpose, after selecting proper domain and boundary conditions, the electric field relating to the problem has been analyzed and then the results in the form of electrical body force have been entered in the governing equations of fluid field (Navier-Stokes equations). The effect of ionic wind resulted from the Electrohydrodynamic actuator, on the velocity, pressure and the wake behind cylinder has been considered. According to the results, it is observed that the fluid flow accelerates in the nearest wall of the frontal half of the cylinder and the pressure difference between frontal and hinder cylinder is increased
Causes of discharge against medical advice in hospitals affiliated with mazandaran university of medical sciences, 2014
Background and purpose: Discharge against medical advice (AMA) has negative impacts on treatment outcomes and health care resources. Also, physicians and hospital administrators get involved in litigation. The aim of this study was to investigate the causes of AMA discharges in different wards and emergency departments in teaching and nonteaching hospitals affiliated with Mazandaran University of Medical Sciences. Materials and methods: This cross-sectional study was performed investigating the AMA leaves within 6 months in 2014. Data was obtained from the Department of Medical Records and the Office of Quality Improvement. Data was recorded in a questionnaire consisting of two parts. Part I included demographic information and Part II was about the reasons of discharge against medical advice. Data was aggregated by expert staff in Office of Quality Improvement. SPSS V.18 was applied for data analysis. Results: The prevalence of AMA leaves in emergency department and other wards in teaching hospitals affiliated with Mazandaran University of Medical Sciences was 3.81 and 4.38, respectively. These figures in nonteaching hospitals were 8.38 and 1.59, respectively. The most common causes of discharge against medical advice were partial recovery, lack of trust in service quality, feeling uncomfortable, and emotional reasons. Conclusion: To reduce the rate of AMA leaves and its consequences, health care staff should be supportive towards the patients and communicate effectively in order to build their confidence. © 2016, Mazandaran University of Medical Sciences. All rights reserved
Robust identification of Parkinson's disease subtypes using radiomics and hybrid machine learning
Objectives: It is important to subdivide Parkinson's disease (PD) into subtypes, enabling potentially earlier disease recognition and tailored treatment strategies. We aimed to identify reproducible PD subtypes robust to variations in the number of patients and features. Methods: We applied multiple feature-reduction and cluster-analysis methods to cross-sectional and timeless data, extracted from longitudinal datasets (years 0, 1, 2 & 4; Parkinson's Progressive Marker Initiative; 885 PD/163 healthy-control visits; 35 datasets with combinations of non-imaging, conventional-imaging, and radiomics features from DAT-SPECT images). Hybrid machine-learning systems were constructed invoking 16 feature-reduction algorithms, 8 clustering algorithms, and 16 classifiers (C-index clustering evaluation used on each trajectory). We subsequently performed: i) identification of optimal subtypes, ii) multiple independent tests to assess reproducibility, iii) further confirmation by a statistical approach, iv) test of reproducibility to the size of the samples. Results: When using no radiomics features, the clusters were not robust to variations in features, whereas, utilizing radiomics information enabled consistent generation of clusters through ensemble analysis of trajectories. We arrived at 3 distinct subtypes, confirmed using the training and testing process of k-means, as well as Hotelling's T2 test. The 3 identified PD subtypes were 1) mild; 2) intermediate; and 3) severe, especially in terms of dopaminergic deficit (imaging), with some escalating motor and non-motor manifestations. Conclusion: Appropriate hybrid systems and independent statistical tests enable robust identification of 3 distinct PD subtypes. This was assisted by utilizing radiomics features from SPECT images (segmented using MRI). The PD subtypes provided were robust to the number of the subjects, and features. © 2020 Elsevier Lt
Efficacy of a topical formulation of henna (Lawsonia inermis L.) in contact dermatitis in patients using prosthesis: A double-blind randomized placebo-controlled clinical trial
Background: Contact dermatitis is a common complication in prosthetic limb users. There are no effective, available and cheap treatments for skin problems of these patients. In traditional Iranian medicine, henna (Lawsonia inermis L.) is a plant that has anti-inflammatory, antimicrobial and skin-enhancing properties, all of which are beneficial for people with artificial limbs. The aim of this study was to assess the efficacy of a topical henna preparation in management of contact dermatitis in patients using lower limb prosthetics. Methods: The current randomized, double-blind, placebo-controlled clinical trial was conducted on ninety-five participants with lower extremity amputation using limb prosthetics, aged 12�70 years who complained of contact dermatitis. They were randomly assigned to receive either two weeks of topical henna preparation every night as the intervention group, or topical placebo as the control group. Participants were instructed to spread henna preparation on the surfaces of the amputated limb that were in contact with the prosthesis. Severity of contact dermatitis symptoms was set as the primary outcome measure. Edema, papules and erythema were evaluated by a physician using standard color atlas. Secondary outcomes included symptoms such as burning, itching, pain, thickness and skin sweating evaluated by a self-administered questionnaire. Results: A significant improvement was observed in the symptoms of contact dermatitis including skin edema, itching, sweating, skin thinning and pain (p-value<0.05) in the henna group compared to the placebo group. Skin burning decreased more in the henna group compared to the placebo group, but this was not statistically significant (p-value = 0.052). Moreover, skin redness significantly increased in the henna group (p-value = 0.001). Conclusion: Topical formulation of henna might be a complementary choice for improving contact dermatitis in patients using lower limb prosthetics. © 2020 Elsevier Lt
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