scholarly journals Effect of Wet Expansion Behavior on Polyimide Membrane Diffractive Lens

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 559 ◽  
Author(s):  
Guohan Gao ◽  
Danbo Mao ◽  
Bin Fan ◽  
Chunlin Guan
Keyword(s):  
Fresnel Zone ◽  
Diffractive Lens ◽  
Flexible Membrane ◽  
Imaging Quality ◽  
Polyimide Membrane ◽  
Fixed Ring ◽  
Expansion Behavior ◽  
Underlying Mechanisms ◽  
Potential Substrate

Optical polyimide (PI) membrane is a potential substrate to fabricate a diffractive primary lens in large aperture space-borne telescope. In this paper, we investigated the wet expansion behavior of PI via a strain gauge method and measured the coefficient of wet expansion (CWE) of PI membrane supported by different fixtures. The CWE of silica-fixed, ring-fixed, and free state PI membrane were near zero, 5 ppm/%, and 10 ppm/% respectively. It is found that Fresnel zone lens (FZL), based on PI membrane with lower CWE, achieve a better imaging quality with smaller wave-front errors. The underlying mechanisms and methods to improve imaging quality of ring-fixed FZL are discussed. This work provides direction in fabricating a flexible membrane diffractive lens with applicable imaging quality.

scholarly journals Sleep disorders in migraine

2021 ◽  
pp. 111-120
Author(s):  
N. V. Vashchenko ◽  
A. I. Kozhev ◽  
Ju. E. Azimovа
Keyword(s):  
Combination Therapy ◽  
Sleep Disorders ◽  
Sleep Disturbances ◽  
Mutual Influence ◽  
Integrated Approach ◽  
Epidemiological Studies ◽  
Exact Nature ◽  
Obstructive Sleep ◽  
Underlying Mechanisms

Migraine and sleep disorders are common in the general population, may be associated with each other and often significantly reduce patients’ quality of life. Clinicians and epidemiological studies have long acknowledged a link between these conditions. However, the exact nature of this relationship, its underlying mechanisms and patterns are complex and not fully understood. This publication brings together the latest data on the relationship between migraine and sleep disorders: the biochemical and functional-anatomical background, the mutual influence of these conditions on each other and the typical sleep disturbances in migraine patients (such as insomnia, obstructive sleep apnea, parasomnia, snoring, excessive daytime sleepiness). The paper discusses the hypotheses of pathogenetic relationships based on the studies of the central nervous system’s anatomical and physiological features in people with migraine and sleep disorders. The available data should encourage physicians to evaluate sleep quality in migraineurs and use combination therapy systematically. The therapy of insomnia is reviewed: both nonpharmacological and pharmacological therapies are discussed; the advantages of an integrated approach are discussed, and a brief overview of each group of medications is offered.Lastly, a case study of a patient with chronic migraine and insomnia treated with Doxylamine in combination therapy is presented. Treatment with Doxylamine significantly reduced the incidence of insomnia, probably thereby positively influencing the course of migraine as well.

scholarly journals SARS-CoV-2 and the Brain: What Do We Know about the Causality of ‘Cognitive COVID?

2021 ◽  
Vol 10 (15) ◽  
pp. 3441
Author(s):  
Hashir Ali Awan ◽  
Mufaddal Najmuddin Diwan ◽  
Alifiya Aamir ◽  
Muneeza Ali ◽  
Massimo Di Giannantonio ◽  
...  
Keyword(s):  
Olfactory Pathway ◽  
Cognitive Sequelae ◽  
Significant Burden ◽  
Inflammatory State ◽  
Underlying Mechanisms ◽  
Acute Changes ◽  
A Minor

The second year of the COVID-19 (coronavirus disease) pandemic has seen the need to identify and assess the long-term consequences of a SARS-CoV-2 infection on an individual’s overall wellbeing, including adequate cognitive functioning. ‘Cognitive COVID’ is an informal term coined to interchangeably refer to acute changes in cognition during COVID-19 and/or cognitive sequelae with various deficits following the infection. These may manifest as altered levels of consciousness, encephalopathy-like symptoms, delirium, and loss of various memory domains. Dysexecutive syndrome is a peculiar manifestation of ‘Cognitive COVID’ as well. In the previous major outbreaks of viruses like SARS-CoV, MERS-CoV and Influenza. There have been attempts to understand the underlying mechanisms describing the causality of similar symptoms following SARS-CoV-2 infection. This review, therefore, is attempting to highlight the current understanding of the various direct and indirect mechanisms, focusing on the role of neurotropism of SARS-CoV-2, the general pro-inflammatory state, and the pandemic-associated psychosocial stressors in the causality of ‘Cognitive COVID.’ Neurotropism is associated with various mechanisms including retrograde neuronal transmission via olfactory pathway, a general hematogenous spread, and the virus using immune cells as vectors. The high amounts of inflammation caused by COVID-19, compounded with potential intubation, are associated with a deleterious effect on the cognition as well. Finally, the pandemic’s unique psychosocial impact has raised alarm due to its possible effect on cognition. Furthermore, with surfacing reports of post-COVID-vaccination cognitive impairments after vaccines containing mRNA encoding for spike glycoprotein of SARS-CoV-2, we hypothesize their causality and ways to mitigate the risk. The potential impact on the quality of life of an individual and the fact that even a minor proportion of COVID-19 cases developing cognitive impairment could be a significant burden on already overwhelmed healthcare systems across the world make it vital to gather further evidence regarding the prevalence, presentation, correlations, and causality of these events and reevaluate our approach to accommodate early identification, management, and rehabilitation of patients exhibiting cognitive symptoms.

scholarly journals A NEW CONCEPT OF DISCRETIZATION MODEL FOR IMAGING IMPROVING IN ULTRASOUND TRANSMISSION TOMOGRAPHY

2019 ◽  
Vol 9 (4) ◽  
pp. 48-51
Author(s):  
Tomasz Rymarczyk ◽  
Krzysztof Polakowski ◽  
Jan Sikora
Keyword(s):  
Noisy Data ◽  
Transmission Tomography ◽  
Imaging Quality ◽  
Internal Objects

In this paper a new version of discretization model for Ultrasonic Transmission Tomography is presented. The algorithm has been extensively tested for synthetic noisy data on various configurations of internal objects. In order to improve the imaging quality, the pixels/voxels have been enlarged compared to the figures inscribed in pixels/voxels however no more than figures described on the standard square pixels or cubic voxels. The proposed algorithm provides better quality of imaging.

Analysis of angle vibration effects on imaging quality of synthetic aperture ladar

Optik ◽  
2018 ◽  
Vol 157 ◽  
pp. 298-305
Author(s):  
Liang Guo ◽  
Wei Li ◽  
Xiaozhen Li ◽  
Guanglie Hong ◽  
Jiangfeng Zhu ◽  
...  
Keyword(s):  
Synthetic Aperture ◽  
Imaging Quality

scholarly journals The Cortisol Awakening Response in Patients with Poststroke Depression Is Blunted and Negatively Correlated with Depressive Mood

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Oh Jeong Kwon ◽  
Munsoo Kim ◽  
Ho Sub Lee ◽  
Kang-keyng Sung ◽  
Sangkwan Lee
Keyword(s):  
Rating Scale ◽  
Area Under The Curve ◽  
Significant Negative Correlation ◽  
Depressive Mood ◽  
Cortisol Awakening Response ◽  
Poststroke Depression ◽  
Stroke Outcomes ◽  
Underlying Mechanisms ◽  
Pituitary Adrenal Axis

It is important to reduce poststroke depression (PSD) to improve the stroke outcomes and quality of life in stroke patients, but the underlying mechanisms of PSD are not completely understood. As many studies implicate dysregulation of hypothalamic-pituitary-adrenal axis in the etiology of major depression and stroke, we compared the cortisol awakening response (CAR) of 28 admitted PSD patients with that of 23 age-matched caregiver controls. Saliva samples for cortisol measurement were collected immediately, 15, 30, and 45 min after awakening for two consecutive days. Depressive mood status in PSD patients was determined with Beck Depression Inventory and Hamilton Depression Rating Scale. Salivary cortisol levels of PSD patients did not rise significantly at any sampling time, showing a somewhat flat curve. Caregiver controls showed significantly higher CAR at 15 and 30 min after awakening compared to PSD patients even though the two groups did not differ at awakening or 45 min after awakening. Area-under-the-curve analysis revealed a significant negative correlation between the CAR and the degree of depression in PSD patients. Thus, our findings suggest that poststroke depression is closely related with dysfunctional HPA axis indicated by blunted CAR.

COLLABORATIVE TESTING IN STATISTICS: GROUP INTERACTION, ANXIETY, AND CLASS PERFORMANCE

2018 ◽  
Vol 17 (2) ◽  
pp. 51-67
Author(s):  
SUSAN KAPITANOFF ◽  
CAROL PANDEY
Keyword(s):  
Social Sciences ◽  
Statistics Education ◽  
Collaborative Testing ◽  
Research Journal ◽  
Collaborative Interactions ◽  
The Social ◽  
Final Exams ◽  
Underlying Mechanisms ◽  
Interaction Anxiety

Seventy-one students in two community college Statistics for the Social Sciences classes took six exams either individually or collaboratively. Assignment to test condition was randomly determined for each exam. Scores on collaboratively-taken exams were significantly higher than those for individually-taken exams, particularly for students with low GPAs and high test anxiety. Women’s, but not men’s, performances on the mid-term and final exams was related to the quality and quantity of their collaborative interactions. Thus, examining both quantity and quality of collaboration adds to our understanding of the underlying mechanisms of collaborative testing. First published November 2018 at Statistics Education Research Journal Archives

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