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An Advanced Light Scattering Imaging Model for Total Internal Reflection Microscopy Considering a Stratified Medium
Get PDFAn advanced light scattering model for Total Internal Reflection Microscopy (TIRM) is presented. The model considers the specific TIRM geometry and deals with the scattering by an axisymmetric particle of arbitrary orientation placed in a stratified medium and the imaging of the scattered field. The scattered field is computed by truncating the scattered and internal field expansions and by using spherical and plane wave expansions for the free-space dyadic Green\u27s function. While the first expansion is valid outside a sphere enclosing the particle, the second one is valid outside the tangent planes bounding the particle from above and below. We demonstrate that in both cases, the results are the same, and thus, that the restrictive condition according to which the interface should not intersect the particle\u27s circumscribed sphere is not relevant. The image of the scattered field is computed by using the Debye diffraction integral and fast Fourier transform, while for a better reconstruction of the particle orientation, an image processing step consisting in a contour extraction and ellipse fitting is considered. The numerical simulations dealing with scattering by a prolate spheroid provide evidence of the remarkably sensitivity of the geometric parameters of the image ellipse to the particle orientation angles, as well as, of the integral response of the detector to the distance between the particle and the interface
A Mechanochemical Approach to Recycle Thermosets Containing Carbonate and Thiourethane Linkages
No full textOver the past decades, various industries shifted from traditional materials such as glass and metals to thermoset polymers due to their excellent chemical resistance, thermal stability, reduced weight, and affordability. However, at the end of their life cycle, these highly crosslinked polymers end up as environmental pollutants due to their non-recyclability. To tackle this issue, researchers are exploring vitrimer-type polymers with recyclable qualities, supporting a circular economy and sustainable management of thermoset wastes. This study investigates a new promising method of recycling two commonly used thermosets in commercial applications, poly allyl diglycol carbonate (PADC) and poly thiourethane (PTU), via a mechanochemical process known as vitrimerization. The process involves the cryogenic ball milling of the thermoset with a zinc-based catalyst and a hydroxyl-providing agent, followed by compression molding, enabling the thermoset conversion into a vitrimer. Rheological tests revealed the remarkable stress-relaxation capabilities of the vitrimerized networks, indicating the conversion of the initial permanent crosslinked structures into dynamic networks through vitrimerization. Dynamic mechanical analysis results show that the vitrimerized samples display a consistent rubbery plateau at high temperature, similar to that of permanently crosslinked networks, suggesting a fix crosslink density during the exchange reaction. Differential scanning calorimetry and thermogravimetric analysis results showed that the thermal properties of the vitrimerized samples closely resemble those of the original samples
Life in a Fishbowl: Space and Environmental Enrichment Affect Behaviour of Betta Splendens
No full textThe public has expressed growing concern for the well-being of fishes, including popular pet species such as the Siamese fighting fish (Betta splendens). In captivity, male Bettas behave aggressively, often causing injuries and death if housed together. As a result, they are typically isolated in small fishbowls, which has been widely criticised as cruel. To investigate the impact of keeping Bettas in these conditions, we recorded the behaviour of individual males in containers of different sizes that were either bare or enriched with gravel, large rocks, and live plants. When male Bettas were housed individually in small bowls (0.5 L) they spent less time swimming than they did when they were kept in larger aquaria (10, 38, and 208 L). Fish that were kept in enriched containers exhibited more instances of swimming. To determine if two male Bettas housed together might coexist peacefully if given enough space and cover from plants and large rocks, we quantified the behaviour of pairs of male Bettas in bare or enriched aquaria of different sizes (10, 38, 208, 378 L). Fish performed fewer approaches and aggressive displays, but not attacks, and more bouts of foraging, when in larger aquaria. This study shows that the small fishbowls typically used in pet stores suppress swimming behaviour in male Bettas and at least a 10-L aquarium is required to ensure full expression of swimming behaviour. Furthermore, even the use of very large aquaria cannot guarantee peaceful cohabitation between two males
Lamellipodia-Mediated Osteoblast Haptotaxis Guided by Fibronectin Ligand Concentrations on a Multiplex Chip
No full textSkull morphogenesis is a complex, dynamic process involving two different germ layers and progressing to the coordinated, directional growth of individual bones. The mechanisms underlying directional growth toward the apex are not completely understood. Here, a microfluidic chip-based approach is utilized to test whether calvarial osteoblast progenitors undergo haptotaxis on a gradient of Fibronectin1 (FN1) via lamellipodia. Mimicking the embryonic cranial mesenchyme\u27s FN1 pattern, FN1 gradients is established in the chip using computer modeling and fluorescent labeling. Primary mouse calvarial osteoblast progenitors are plated in the chip along an array of segmented gradients of adsorbed FN1. The study performs single-cell tracking and measures protrusive activity. Haptotaxis is observed at an intermediate FN1 concentration, with an average directional migration index (yFMI) of 0.07, showing a significant increase compared to the control average yFMI of -0.01. A significant increase in protrusive activity is observed during haptotaxis. Haptotaxis is an Arp2/3-dependent, lamellipodia-mediated process. Calvarial osteoblast progenitors treated with the Arp2/3 (Actin Related Protein 2/3 complex) inhibitor CK666 show significantly diminished haptotaxis, with an average yFMI of 0.01. Together, these results demonstrate haptotaxis on an FN1 gradient as a new mechanism in the apical expansion of calvarial osteoblast progenitors during development and shed light on the etiology of calvarial defects
Excess Prevalence of Preexisting Chronic Conditions in Older Adults with Incident Epilepsy
No full textObjective: Prior studies have examined chronic conditions in older adults with prevalent epilepsy, but rarely among those with incident epilepsy. Identifying the chronic conditions with which older adults present at epilepsy incidence assists with the evaluation of disease burden in this patient population and informs coordinated care development. The aim of this study was to identify preexisting chronic conditions with excess prevalence in older adults with incident epilepsy compared to those without. Methods: Using a random sample of 4 999 999 fee-for-service Medicare beneficiaries aged \u3e65 years, we conducted a retrospective cohort study of epilepsy incidence in 2019. Non-Hispanic Black and Hispanic beneficiaries were oversampled. We identified preexisting chronic conditions from the 2016–2018 Medicare Beneficiary Summary Files and compared chronic condition prevalence between Medicare beneficiaries with and without incident epilepsy in 2019. We characterized variations in preexisting excess chronic condition prevalence by age, sex, and race/ethnicity, adjusting for the racial/ethnic oversampling. Results: We observed excess prevalence of most preexisting chronic conditions in beneficiaries with incident epilepsy (n = 20 545, weighted n = 19 631). For stroke, for example, the adjusted prevalence rate ratio (APRR) was 4.82 (99% CI:4.60, 5.04), meaning that, compared to those without epilepsy, beneficiaries with incident epilepsy in 2019 had 4.82 times the stroke prevalence. Similarly, beneficiaries with incident epilepsy had a higher prevalence rate for preexisting neurological conditions (APRR = 3.17, 99% CI = 3.08–3.27), substance use disorders (APRR = 3.00, 99% CI = 2.81–3.19), and psychiatric disorders (APRR = 1.98, 99% CI = 1.94–2.01). For most documented chronic conditions, excess prevalence among beneficiaries with incident epilepsy in 2019 was larger for younger age groups compared to older age groups, and for Hispanic beneficiaries compared to both non-Hispanic White and non-Hispanic Black beneficiaries. Significance: Compared to epilepsy-free Medicare beneficiaries, those with incident epilepsy in 2019 had a higher prevalence of most preexisting chronic conditions. Our findings highlight the importance of health promotion and prevention, multidisciplinary care, and elucidating shared pathophysiology to identify opportunities for prevention
A High-Tech Wreck: HIPAA Roadblocks to Texting Patients
Get PDFProtecting the private and confidential information entrusted to health care professionals is a core principle dating back to the Hippocratic Oath. At the same time, effective health communication is essential to build trust and allow patients and families to understand and participate as true members of the team. Although it is not often discussed, there can be a tension between legal security regulations designed to protect confidentiality and the ability to effectively communicate with families. The main source of this tension in the United States is related to the Health Insurance Portability and Accountability Act (HIPAA). At the dawn of the electronic medical record era, Congress was concerned about security and so in 1996 passed the Health Insurance Portability and Accountability Act (HIPAA). Under HIPAA, there are potential civil and criminal penalties for failing to protect specified health information. These are not merely theoretical punishments. Since inception there have been several hundred thousand complaints of HIPAA violations and the Office for Civil Rights has levied several high profile multi-million dollar fines for violations, including a record $16 million dollar fine against Anthem, Inc. in 2018. This has understandably made health care institutions highly risk averse. But have they become too risk averse, and at what cost? In this issue of Journal of Perinatology, Lindsey et al. discuss the legal barriers they encountered when attempting to use text messaging-based digital health interventions as part of a randomized controlled trial specifically designed to improve maternal and neonatal outcomes in marginalized communities. While developing the well-named POPPY trial, standing for Providing an Optimized and emPowered Pregnancy for You, the goal was to use text messaging as a quick and accessible way to deliver pregnancy-related health care information to patients living in the 4th or 5th Quintile of the Area Deprivation Index. Patients from these areas often lack stable access to the smartphones and internet that are often used to interact with health care systems. They do, however, almost always have access to text messaging, which is widely accessible and indeed one of the most common forms of communication. Mobile phone users in the United States sent approximately 2 trillion text messages in 2021 alone. Technology has had a revolutionary impact on almost all aspects of society in the past few decades, and provided a number of benefits to patients and healthcare professionals. But there are concerns that there is unequal distribution of these benefits leading to a ‘digital divide.’ Indeed, to the extent that technology has the ability to improve health outcomes, lack of access to technology can lead to an even greater gap as “populations that have poorer health outcomes continue to have poorer health outcomes despite technological improvements.”Footnote 4 The POPPY trial envisioned bridging this divide by using simple text messaging to improve access to quality health information and improve both the care and experience during pregnancy and after delivery. Due to HIPAA concerns, however, the investigators were forbidden from using simple text messaging and instead required to implement security measures involving increased complexity, additional clicks, and a secure browser requiring internet access. Unsurprisingly, engagement with the promising intervention declined, in part due to the fact that access was now denied to patients with a mobile phone that had texting ability but no internet capability. An intervention specifically designed to improve inclusion and accessibility was now less accessible and less inclusive. As the authors recognize, it is a “formidable challenge” to appropriately balance effective communication with privacy. Possible solutions will involve healthcare institution’s developing and sharing innovative approaches. The Department of Health and Human Services, which regulates HIPAA, must be involved as well. Most important is involving, and listening to, affected patients who will have crucial opinions on effective solutions. Patients want and expect their health information to remain protected and confidential, and it is essential that pregnant women feel comfortable disclosing highly sensitive and personal information to receive optimal maternity care. At the same time, a key purpose of HIPAA was to improve “the efficiency and effectiveness of the health care system.”Footnote 5 Lindsey et al. are to be commended for sharing the barriers they faced when attempting to use texting to improve patient outcomes, as it is only when problems are shared that solutions can be developed
ASO Author Reflections: Outcomes of Hepatic Artery-Based Therapies and Systemic Multiagent Chemotherapy in Unresectable Colorectal Liver Metastases: A Systematic Review and Meta-Analysis
Get PDFNonpharmacologic Rate Control of Postoperative Atrial Fibrillation in the Canine Sterile Pericarditis Model
Get PDFIntroduction: Postoperative atrial fibrillation (POAF) is common following open heart surgery, and is associated with significant morbidity. Medications used for ventricular rate control of POAF may not be effective in controlling rapid ventricular rates during the postoperative period because of increased sympathetic tone. The purpose of this study was to develop nonpharmacologic rate control of POAF by atrioventricular node (AVN) fat pad stimulation using clinically available temporary pacing wires in the canine sterile pericarditis model. Methods: We studied 10 sterile pericarditis dogs in the closed-chest state on postoperative days 1−3. The AVN fat pad stimulation (amplitude 2–15 mA; frequency 20 Hz; pulse width 0.03–0.2 ms) was performed during sustained POAF (\u3e5 min). We measured ventricular rate and inefficient ventricular contractions during sustained POAF and compared it with and without AVN fat pad stimulation. Also, the parameters of AVN fat pad stimulation to achieve a rate control of POAF were measured over the postoperative days. Results: Eleven episodes of sustained POAF were induced in 5/10 sterile pericarditis dogs in the closed-chest state on postoperative days 1−2. During POAF, the AVN fat pad stimulation decreased the ventricular rate from 178 ± 52 bpm to 100 ± 8 bpm in nine episodes. Nonpharmacologic rate control therapy successfully controlled the ventricular rate and eliminated inefficient ventricular contractions during POAF for the duration of the AVN fat pad stimulation. The AVN fat pad stimulation output remained relatively stable over the postoperative days. Conclusion: During sustained POAF, nonpharmacologic rate control by AVN fat pad stimulation effectively and safely controlled rapid ventricular rates throughout the postoperative period
Speech-Language Pathology in China: An Overview
Get PDFPurpose: China is a middle-income developing country that is aging rapidly. Speech-language pathology is a developing field in China. The article aims to provide a brief overview of the current status of speech-language pathology in China.
Method: This article presents the authors\u27 viewpoint, bolstered by insights from nine speech-language pathologists (SLPs) in China. To enrich the depth of the discussion on achievements and challenges within the Chinese speech-language pathology field, the authors also conducted a review of relevant articles in Standard Chinese–based databases.
Result and Discussion: The authors have delineated both the major achievements and barriers in the field of speech-language pathology in China. Recommendations for improvement are included, emphasizing the importance of sustained efforts from researchers, clinicians, educators, governments, and related organizations within China. Additionally, the authors extend their suggestions to clinicians and researchers in other countries.
Conclusion: While the field of speech-language pathology has substantially developed in the past 40 years, several challenges confront SLPs in China at both the educational and practical levels
uHD: Unary Processing for Lightweight and Dynamic Hyperdimensional Computing
Get PDFHyperdimensional computing (HDC) is a novel computational paradigm that operates on long-dimensional vectors known as hypervectors. The hypervectors are constructed as long bit-streams and form the basic building blocks of HDC systems. In HDC, hypervectors are generated from scalar values without considering bit significance. HDC is efficient and robust for various data processing applications, especially computer vision tasks. To construct HDC models for vision applications, the current state-of-the-art practice utilizes two parameters for data encoding: pixel intensity and pixel position. However, the intensity and position information embedded in high-dimensional vectors are generally not generated dynamically in the HDC models. Consequently, the optimal design of hypervectors with high model accuracy requires powerful computing platforms for training. A more efficient approach is to generate hypervectors dynamically during the training phase. To this aim, this work uses low-discrepancy sequences to generate intensity hypervectors, while avoiding position hypervectors. Doing so eliminates the multiplication step in vector encoding, resulting in a powerefficient HDC system. For the first time in the literature, our proposed approach employs lightweight vector generators utilizing unary bit-streams for efficient encoding of data instead of using conventional comparator-based generators
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