bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug Shortages in Oncology: ASCO Clinical Guidance for Alternative Treatments
Authors: Santos Edgardo S. , Oliver Thomas K. , Lacchetti Christina , Geisel Rachel , Wilfong Lalan S. , Fader Amanda N. , Eng Cathy
Published: November 2023

PURPOSE

To increase awareness, outline strategies, and offer clinical guidance on navigating the complexities of treatment planning amid antineoplastic drug shortages.

METHODS

A multidisciplinary panel of oncologists, ethicists, and patient advocates was assembled to provide rapid clinical guidance to help providers navigate appropriate patient care in cases where rationing or alternative therapies must be considered. The groups of content experts developed general principles for resource allocation during shortages and clinical guidance on alternative therapies for specific disease sites. The recommendations are supported by evidence when available.

RESULTS

A total of 44 volunteers with content expertise formed the Advisory Group that developed general guidance on the prioritization of antineoplastic agents in limited supply. Disease site–specific clinical guidance was then produced by subgroups on the basis of members' specialties and expertise. The majority of alternative treatment options were developed in consideration of cisplatin and carboplatin shortages. All guidance is posted on ASCO's website.

RECOMMENDATIONS

The prioritization of antineoplastic agents in limited supply should be based on specific goals of the therapy where evidence-based medicine has shown survival outcome and life-extending benefit in both early and advanced stages. Recommendations for specific disease sites are presented. While management options vary according to the disease site, alternatives are presented. For settings in which there are no alternatives with comparable efficacy and safety, it is recommended that patients are referred to an area where the necessary drug is available or can be obtained. Additional information is available at asco.org/drug-shortages .
Characterizing exceptional points using neural networks
Authors: Reja Afsar , Narayan Awadhesh
Published: November 2023

One of the key features of non-Hermitian systems is the occurrence of exceptional points (EPs), spectral degeneracies where the eigenvalues and eigenvectors merge. In this work, we propose applying neural networks to characterize EPs by introducing a new feature —summed phase rigidity (SPR). We consider different models with varying degrees of complexity to illustrate our approach, and show how to predict EPs for two-site and four-site gain and loss models. Further, we demonstrate an accurate EP prediction in the paradigmatic Hatano-Nelson model for a variable number of sites. Remarkably, we show how SPR enables a prediction of EPs of orders completely unseen by the training data. Our method can be useful to characterize EPs in an automated manner using machine learning approaches.
Building a “trap model” of glassy dynamics from a local structural predictor of rearrangements
Authors: Ridout S. A. , Tah I. , Liu A. J.
Published: November 2023

Here we introduce a variation of the trap model of supercooled liquids based on softness, a particle-based variable identified by machine learning that quantifies the local structural environment and energy barrier for the particle to rearrange. As in the trap model, we assume that each particle's softness, and hence energy barrier, evolves independently. We show that our model makes qualitatively reasonable predictions of behaviors such as the dependence of fragility on density in a model supercooled liquid. We also show failures of the model, indicating in some cases signs that softness may be missing important information, and in other cases features that may only be explained by correlations neglected in the trap model.
The Global Plastics Treaty: An Endocrinologist's Assessment
Authors: Fernandez Marina Olga , Trasande Leonardo
Published: November 2023

Plastics are everywhere. They are in many goods that we use every day. However, they are also a source of pollution. In 2022, at the resumed fifth session of the United Nations Environment Assembly, a historic resolution was adopted with the aim of convening an Intergovernmental Negotiating Committee to develop an international legally binding instrument on plastic pollution, including in the marine environment, with the intention to focus on the entire life cycle of plastics. Plastics, in essence, are composed of chemicals. According to a recent report from the secretariat of the Basel, Rotterdam, and Stockholm conventions, around 13 000 chemicals are associated with plastics and plastic pollution. Many of these chemicals are endocrine-disrupting chemicals and, according to reports by members of the Endocrine Society and others, exposure to some of these chemicals causes enormous costs due to the development of preventable diseases. The global plastics treaty brings the opportunity for harmonized, international regulation of chemicals with endocrine disrupting properties present in plastic products.
An Artificial Neural Network Model for Predicting Postoperative Facial Nerve Outcomes After Vestibular Schwannoma Surgery
Authors: Zohdy Youssef M. , Alawieh Ali M. , Bray David , Pradilla Gustavo , Garzon-Muvdi Tomas , Ashram Yasmine A.
Published: November 2023

BACKGROUND AND OBJECTIVES:

The emergence of machine learning models has significantly improved the accuracy of surgical outcome predictions. This study aims to develop and validate an artificial neural network (ANN) model for predicting facial nerve (FN) outcomes after vestibular schwannoma (VS) surgery using the proximal-to-distal amplitude ratio (P/D) along with clinical variables.

METHODS:

This retrospective study included 71 patients who underwent VS resection between 2018 and 2022. At the end of surgery, the FN was stimulated at the brainstem (proximal) and internal acoustic meatus (distal) and the P/D was calculated. Postoperative FN function was assessed using the House-Brackmann grading system at discharge (short-term) and after 9–12 months (long-term). House-Brackmann grades I–II were considered good outcome, whereas grades III–VI were considered fair/poor. An ANN model was constructed, and the performance of the model was evaluated using the area under the ROC curve for internal validation and accuracy, sensitivity, specificity, and positive and negative predictive values for external validation.

RESULTS:

The short-term FN outcome was grades I–II in 57.7% and grades III–VI in 42.3% of patients. Initially, a model using P/D had an area under the curve of 0.906 (internal validation) and an accuracy of 89.1% (95% CI: 68.3%-98.8%) (external validation) for predicting good vs fair/poor short-term FN outcomes. The model was then refined to include only muscles with a P/D with a proximal latency between 6 and 8 ms. This improved the accuracy to 100% (95% CI: 79%-100%). Integrating clinical variables (patient's age, tumor size, and preoperative HB grade) in addition to P/D into the model did not significantly improve the predative value. A model was then created to predict the long-term FN outcome using P/D with latencies between 6 and 8 ms and had an accuracy of 90.9% (95% CI: 58.7%-99.8%).

CONCLUSION:

ANN models incorporating P/D can be a valuable tool for predicting FN outcomes after VS surgery. Refining the model to include P/D with latencies between 6 and 8 ms further improves the model's prediction. A user-friendly interface is provided to facilitate the implementation of this model.
Social Determinants of Health Impact Spinal Cord Injury Outcomes in Low- and Middle-Income Countries: A Meta-Epidemiological Study
Authors: Covell Michael M. , Naik Anant , Shaffer Annabelle , Cramer Samuel W. , Alan Nima , Shabani Hamisi K. , Rabiel Happiness , Rosseau Gail , Arnold Paul M.
Published: November 2023

BACKGROUND AND OBJECTIVES:

Traumatic spinal cord injuries (SCI), which disproportionally occur in low- and middle-income countries (LMICs), pose a significant global health challenge. Despite the prevalence and severity of SCI in these settings, access to appropriate surgical care and barriers to treatment remain poorly understood on a global scale, with data from LMICs being particularly scarce and underreported. This study sought to examine the impact of social determinants of health (SDoH) on the pooled in-hospital and follow-up mortality, and neurological outcomes, after SCI in LMICs.

METHODS:

A systematic review was conducted in adherence to the Preferred Reporting in Systematic Review and Meta-Analysis-guidelines. Multivariable analysis was performed by multivariable linear regression, investigating the impact of the parameters of interest (patient demographics, country SDoH characteristics) on major patient outcomes (in-hospital/follow-up mortality, neurological dysfunction).

RESULTS:

Forty-five (N = 45) studies were included for analysis, representing 13 individual countries and 18 134 total patients. The aggregate pooled in-hospital mortality rate was 6.46% and 17.29% at follow-up. The in-hospital severe neurological dysfunction rate was 97.64% and 57.36% at follow-up. Patients with rural injury had a nearly 4 times greater rate of severe in-hospital neurological deficits than patients in urban areas. The Gini index, reflective of income inequality, was associated with a 23.8% increase in in-hospital mortality, a 20.1% decrease in neurological dysfunction at follow-up, and a 12.9% increase in mortality at follow-up.

CONCLUSION:

This study demonstrates the prevalence of injury and impact of SDoH on major patient outcomes after SCI in LMICs. Future initiatives may use these findings to design global solutions for more equitable care of patients with SCI.
Supramaximal Testing to Confirm the Achievement of V̇O2max in Acute Hypoxia
Authors: Thompson Benjamin P. , Doherty Connor J. , Mann Leah M. , Chang Jou-Chung , Angus Sarah A. , Foster Glen E. , Au Jason S. , Dominelli Paolo B.
Published: November 2023

To confirm maximal oxygen uptake (V̇O2max), a bout of supramaximal exercise can be performed after maximal exercise. Supramaximal exercise verifies V̇O2max if the V̇O2max is similar to the incremental test. Acute hypoxia decreases V̇O2max due to decreases in arterial oxygenation which results in different determinants of V̇O2max.

Purpose

We sought to determine if supramaximal exercise testing confirms the achievement of V̇O2max in acute hypoxia. We hypothesized that the incremental and supramaximal V̇O2 will be sufficiently similar in acute hypoxia.

Methods

Twenty-one healthy adults (males n = 13, females n = 8) completed incremental and supramaximal exercise tests in normoxia and acute hypoxia (fraction inspired oxygen = 0.14) separated by at least 48 hours. Incremental exercise started at 80 and 60 W in normoxia and 40 and 20 W in hypoxia for males and females, respectively, with all increasing by 20 W each minute until volitional exhaustion. Following a 20 minute post-exercise rest period, a supramaximal test at 110% peak power until volitional exhaustion was completed.

Results

Supramaximal exercise testing yielded a lower V̇O2 than incremental testing in hypoxia (3.11 ± 0.78 vs. 3.21 ± 0.83 L min-1, p = 0.001) and normoxia (3.71 ± 0.91 vs. 3.80 ± 1.02 L min-1, p = 0.01). Incremental and supramaximal V̇O2 were statistically similar, using investigator-determined equivalence bounds ±150 mL min-1, in hypoxia (p = 0.02, 90% CI = [0.05 , 0.14]) and normoxia (p = 0.03, 90% CI = [0.01 , 0.14]. Likewise, using ±2.1 mL kg-1 min-1 bounds, incremental and supramaximal V̇O2 was statistically similar in hypoxia (p = 0.04, 90% CI = [0.70 , 2.0]) and normoxia (p = 0.04, 90% CI = [0.30 , 2.0]).

Conclusions

Despite differences in the oxygen cascade, the incremental and supramaximal V̇O2 were statistically similar in both hypoxia and normoxia, demonstrating the utility of supramaximal verification of V̇O2max in the setting of acute hypoxia.
The Effects of a 10-day Military Field Exercise on Body Composition, Physical Performance, and Muscle Cells in Men and Women
Authors: Vikmoen Olav , Teien Hilde Kristin , Tansø Rita , Aandstad Anders , Lander Elise , Cumming Kristoffer T. , Ellefsen Stian , Helkala Kirsi , Raastad Truls
Published: November 2023

Purpose

To investigate the effects of a demanding military field exercise on physical performance, body composition and muscle cellular outcomes in men and women.

Methods

Ten men (20.5 ± 0.5 years) and 8 women (21.4 ± 1.4 years) completed a 10-day field exercise consisting of extensive physical activity with food and sleep restriction. Acquisition of body composition, physical performance, blood and muscle biopsies samples were done before and 1,7 and 14 days after the exercise.

Results

There were no sex differences in the response to the exercise. Body mass was decreased with 5.6 ± 1.8% and fat mass with 31 ± 11% during the exercise. Both were still reduced after 14 days (2.5 ± 2.3%, p˂0.001 and 12.5 ± 7.7%, p˂0.001 respectively). Isometric leg strength did not change. Peak leg extension torque at 240 °·s-1 and counter movement jump height were reduced with 4.6 ± 4.8% (p = 0.012) and 6.7 ± 6.2% (p˂0.001) respectively and was still reduced after 14 days (4.3 ± 4.2%, p = 0.002, and 4.1 ± 4.7%, p = 0.030). No changes occurred in fiber CSA, fiber types, proteins involved in calcium handling or HSP70. During the exercise, αB-crystallin levels decreased by 14 ± 19% (p = 0.024) in the cytosolic fraction and staining intensity on muscle sections tended to increase (17 ± 25%, p = 0.076). MuRF1 levels in the cytosolic fraction tended to decrease (19 ± 35%) and increased with 85 ± 105% (p = 0.003) in the cytoskeletal fraction 1 week after the exercise.

Conclusions

The field exercise resulted in reduced body mass and physical performance in both sexes. The ability to produce force at high contraction velocities and explosive strength was more affected than isometric strength, but this was not related to any changes in fiber type composition, fiber area, Ca2+ handling or fiber type specific muscle damage.
Πρωτόκολλο μελέτης της αποτελεσματικότητας της διουρηθρικής προστατεκτομής υποβοηθούμενης με χρήση Thulium laser
Authors: Κοτσίρης Δημήτριος
Published: November 2023

Σκοπός: Η σύγκριση των περιεγχειρητικών και μετεγχειρητικών αποτελεσμάτων μεταξύ της διουρηθρικής προστατεκτομής (Oyster technique) με χρήση Tm-YAG laser και της συμβατικής διουρηθρικής προστατεκτομής με χρήση μονοπολικής ενέργειας. Μέθοδοι: Ασθενείς με LUTS και με μέγεθος προστάτου τουλάχιστον 60ml κατανεμήθηκαν τυχαία σε μία από τις δύο παράλληλες ομάδες για να υποβληθούν σε εξάχνωση προστάτου με Tm-YAG laser (Ομάδα 1) ή σε συμβατική μονοπολική διουρηθρική προστατεκτομή (Ομάδα 2). Τα πρωτεύοντα καταληκτικά σημεία ήταν η μείωση του IPSS και η αύξηση της Qmax μετεγχειρητικά. Τα δευτερεύοντα καταληκτικά σημεία περιλάμβαναν την πτώση της αιμοσφαιρίνης, το ποσοστό επιπλοκών, τις μεταβολές στις ουροδυναμικές παραμέτρους, τη διάρκεια νοσηλείας και καθετηριασμού και τις μεταβολές στο IIEF κατά τη διάρκεια της 24μηνης παρακολούθησης. Αποτελέσματα: Συνολικά 32 και 30 ασθενείς συμμετείχαν στις ομάδες 1 και 2, αντίστοιχα. Η ηλικία των ασθενών (p=0,422) και ο όγκος του προστάτη ήταν παρόμοιες μεταξύ των ομάδων (p=0,51). Τα αποτελέσματα όσον αφορά στη μείωση του IPSS και στη βελτίωση του Qmax ήταν συγκρίσιμα (p=0,449 και p=0,237 αντίστοιχα). Οι χρόνοι χειρουργικής επέμβασης και νοσηλείας ήταν χαμηλότεροι στην ομάδα 1 (p=0,002 και p=0,004 αντίστοιχα). Η πτώση της αιμοσφαιρίνης, οι μεταβολές στις ουροδυναμικές παραμέτρους και η βελτίωση στις βαθμολογίες IIEF και QoL δεν διέφεραν μεταξύ των δύο ομάδων. Ο μέσος χρόνος με τον καθετήρα ήταν 2,06 ±0,35 και 2,5 ±0,82 (p=0,003) ημέρες για την Ομάδα 1 και την Ομάδα 2, αντίστοιχα. Το συνολικό ποσοστό επιπλοκών ήταν 6,2% για την Ομάδα 1 και 13,3% για την Ομάδα 2. Συμπεράσματα: Η τεχνική Oyster οδηγεί σε παρόμοια μετεγχειρητικά αποτελέσματα σε σύγκριση με τη συμβατική διουρηθρική προστατεκτομή. Ο συντομότερος σε διάρκεια καθετηριασμός, η νοσηλεία και ο χρόνος επέμβασης θα πρέπει να θεωρούνται πλεονεκτήματα της τεχνικής Oyster.
Association of vitamin A and zinc with the development of diabetic retinopathy
Authors: Yeasmin Farjana , Rahman Md Asikur , Chowdhury Nafisa Marzan , Khadija Sheikh , Joarder Taufique , Mishu Farzana Akonjee
Published: November 2023

Introduction: Diabetic Retinopathy is a common microvascular disorder in people with diabetes mellitus. It is characterized by a variety of lesions within the retina and is the leading cause of blindness in adults. Hyperglycemia promotes the formation of reactive oxygen species and increased concentrations locally and throughout the body, even to the point of exceeding antioxidant capacity, a condition known as oxidative stress affecting retinal integrity. Antioxidants and trace elements are responsible for reducing oxidative damage. Vitamin A and Zinc have antioxidant properties.

Objective: To evaluate vitamin A and Zinc levels in diabetic patients with and without diabetic retinopathy.

Methods: Cross-sectional study was done in BIRDEM General Hospital and the CARS, University of Dhaka, from January 2021 to December 2021. Study parameters Fasting Blood Glucose, HbA1c, Vitamin A, and Zinc were estimated by standard laboratory methods. According to the inclusion criteria, 100 subjects over 30 years were included. They were divided into two groups; 50 were patients with diabetic retinopathy, and 50 were without diabetic retinopathy. After taking informed written consent, a structured questionnaire was filled up for each subject to collect data. Data were analyzed by independent student t-test, Chi-square test, and Pearson’s correlation test.

Results: The study showed that vitamin A was significantly lower in patients with diabetic retinopathy (8.95±8.12) than in patients without diabetic retinopathy (22.39±11.56). Zinc level was also decreased in cases of group I (1.17±0.31) than in group II (1.43±3.60). Vitamin A had a significant negative correlation between FBG and HbA1c. But Zinc did not show a significant correlation with FBG and HbA1c. This study also found a significant positive correlation between vitamin A with Zinc.

Conclusion: In this study, we found that vitamin A and zinc were significantly lower in patients with retinopathy than in patients without retinopathy.
The ESCAPE Open-source Software and Service Repository
Authors: Vuillaume Thomas , Al-Turany Mohammad , Füßling Matthias , Gal Tamas , Garcia Enrique , Graf Kay , Hughes Gareth , Kettenis Mark , Kresan Dmytro , Schnabel Jutta , Tacke Christian , Verkouter Marjolein
Published: November 2023

Purpose The purpose of the ESCAPE Open-source Software and Service Repository (OSSR) is to provide a central location for the dissemination and use of trusted open-source software in the fields of astronomy, astroparticle physics, and particle physics. The repository allows users to easily access and download tools and services developed within the community, and to contribute their own tools and services. Methods The ESCAPE project has set up a curated repository of software that provides tools and an environment to make it easy for users to find and download the software and services that they need. The repository is regularly updated and is maintained by a curation board, ensuring that the software and services are reliable and up-to-date. The curation and onboarding process makes the OSSR a trustworthy source of software that can be used for scientific analysis. The software included in the repository must include documentation and instructions and follow a set of modern best practices in software development. Training is provided to students and researchers to help them provide high-quality scientific software following modern software development practices. Outcome The OSSR currently contains a wide range of software and services, including those for data management, data analysis, and machine learning. These tools and services are used by researchers and other users around the world. The OSSR has proven to be an effective means for disseminating and providing open-source software and services developed by the ESCAPE project partners and welcomes contributions from the entire community.
Odynophagia in individuals with neck pain: the importance of differential diagnosis in physiotherapy practice
Authors: Polastri Massimiliano , Di Marco Luca , Andreoli Ernesto
Published: November 2023

Odynophagia refers to painful swallowing caused by various underlying factors that must be excluded to determine the best treatment approach. Neck pain is a debilitating condition requiring treatment in rehabilitative settings. There are several circumstances in which odynophagia and neck pain coexist, such as tendinitis of the longus colli muscle and paravertebral calcification, prevertebral and retropharyngeal abscess, esophageal perforation, aortic dissection, thyroid cartilage fracture, thyrohyoid ligament syndrome, pneumomediastinum and subcutaneous emphysema, and after physical exercise. Physiotherapists are professionals most likely to encounter individuals with neck pain and provide interventions such as massage, manual therapy, exercise, and electrotherapy. Therefore, it is important to recognize that neck pain can stem from different clinical conditions that require interventions other than physiotherapy. A differential diagnosis is crucial to ensure appropriate referrals for therapeutic interventions.
Efficiency of using individual biogas digesters for processing biowaste of rural households in Ukraine
Authors: Pryshliak Natalia , Shynkovych Andrii , Tokarchuk Dina , Korpaniuk Tatiana
Published: November 2023

Biogas production is a promising area for the development of alternative energy sources in Ukraine and in the world. The aim of this study is to investigate the possibilities of implementing individual biogas digesters in rural households in Ukraine and to determine the energy, economic and environmental benefits of biogas production from organic waste. As part of the study, an analysis of the main characteristics of households in Ukraine was carried out and the prerequisites for organising biogas production by households were determined. Household incomes were analysed, and it was determined that the costs of housing and communal services tend to grow. It was determined that the price of natural gas for the population over the past years has increased by almost 10 times, and thus replacing natural gas with biogas becomes especially relevant. The positive economic and environmental factors of using individual biogas plants in rural areas were characterised, and the theoretically possible potential of biogas production from household waste in Ukraine was calculated. Following this, a number of government measures to promote the proliferation of individual biogas plants were proposed. The economic benefits from the use of biogas were determined, including energy autonomy, the possibility of using organic fertilisers, and additional profit from the sale of surplus products. The ecological effect of using individual biogas plants will include the possibility of recycling organic waste and waste water, thus improving the hygiene situation for individual users.

Individual biogas digesters constitute a promising direction in Ukraine in terms of energy (production of biogas) and ecological areas (household waste management and production of organic fertilisers). At present, the sector of individual biogas production from biowaste is not widely spread in Ukraine, due to the lack of state support and insufficient awareness among rural residents about the benefits of biogas technology. In this research we determined the economic efficiency of the construction and operation of an individual biogas plant. Considering the average price of natural gas in Ukraine (229.9 USD per 1000 m3), the use of a biogas plant would save 144.1 USD annually on the purchase of natural gas. Given that the cost of building an individual biogas digester is 825.6 USD, its payback period would be 4.7 years.
In search of inspiration: Pioneers and promoters of rural sociology
Authors: Piszczek Elwira
Published: November 2023

This article refers to Gerd Vonderach’s publications showing the relevance of discovering and (re)using the existing output of the social sciences. With reference to the terms Pioniere and Ideengeber, this paper introduces selected classic figures of the social sciences in German-speaking countries and the discussions and controversies that have arisen in the course of analysing their work.
Introduction to the Issue
Authors: Marchevsky Ondrej
Published: November 2023

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Jaspers’s Struggle for the Idea of the University
Authors: Prazny Ales
Published: November 2023

The aim of the study presented here is to show that Jasper’s idea of university is intended to present a defence of philosophical life of a university against its reduction to a merely utilitarian concept. Jaspers follows up on the enlightened role of philosophy within university education and develops it in the conditions of the dark twentieth century. He views philosophical life as a precondition for preserving university as a place of a close bond between science and humanity, which turned out to be much needed at a time of the rise of Nazism in Germany. The study shows the crucial importance of philosophy, science and education in Jaspers' thought for the preservation of a free university. This study shows, within a historical context, the restoration of university in democratic conditions after the end of the Nazi Era.
PHILOSOPHY AND CREATIVITY WITH CHILDREN: LIPMAN, VYGOTSKY, RODARI.
Authors: Naldoniová Lenka
Published: November 2023

The article is focused on the topic of how to practice philosophy and support creativity in kindergartens and elementary schools with the help of fairy tales, in particular with the help of the story of Pinocchio. Emphasis is placed on Lipman's activity of philosophy for children, which he tried to connect with Vygotsky's theories. The aim of the article is to show the importance of developing critical thinking in the form of dialogue in connection with creative thinking, which Gianni Rodari focused on. Rodari was based on Vygotsky's theory of imagination as a process of the human mind, which is a characteristic of all human being.
TWO STEP CHEMICAL TREATMENT ON FLAX FIBERS FOR ENHANCED INTERFACIAL ADHESION AND MOISTURE REPULSION
Authors: VATTATHURVALAPPIL SUHAIL HYDER , THERAVALAPPIL RAJESH , ARAVIND ABDUL RAHMAN , KUMAR ARUMUGAM MADHAN , ALI USMAN
Published: November 2023

Due to their reversible and sustainable properties, natural fiber thermoplastic composites are gaining popularity. The widespread use of natural fibers as reinforcements in structural components is hindered by their moisture adsorption and poor mechanical properties. In this investigation, alkaline treated and untreated flaxbased high-density polyethylene (HDPE) composites were manufactured and exposed to accelerated weathering tests in accordance with ASTM G154-23, to examine their moisture absorption behavior and rate of degradation. The tensile strength of alkalinetreated samples increased by 36 percent prior to accelerated ageing, but the elastic modulus and strain to failure remain unchanged. The post-ageing tests estimated a small increase in the fracture energy of the alkaline treated samples. However, no significant difference was obtained in elastic modulus, tensile strength and strain to failure. Further, the elastic modulus of both treated and untreated samples increased due to embrittlement, which shows the ineffectiveness of alkaline treatment on flax fibers under extreme weathering conditions.
MODELING OF THE IMPACT RESPONSE OF THERMOPLASTIC COMPOSITES
Authors: VOLETI SREENIVASA R. , RAO PRABHAKAR M. , PEREIRA MICHAEL
Published: November 2023

This work investigates simulation of the global deformation and damage progression response of a thermoplastic panel under high energy ballistic impact. The composite material system is a carbon fiber reinforced low melt semi-crystalline resin TC1225 LMPAEK T700G (T700/LMPAEK†). Several high energy dynamic impact tests were performed where an aluminum projectile impacted various panels at different impact velocities. For this work, the test performed at an impact velocity of 73.2 m/s was investigated. The projectile rebounded upon impact, and the damage to the panel was characterized through ultrasonic C-scanning. Response of the panel under impact and the associated damage is discussed. Numerical simulation of the impact process was performed using the LS-DYNA® computer code [1] with a new material model MAT_COMPOSITE_DAMAGE_DGD (MAT 299), a modification to the MAT 261 material model in terms of an improved representation of damage coupling and additional capability for strain rate effects. Delaminations were modeled using cohesive zone contact formulation in LS-DYNA®, wherein the mixed-mode fracture is captured via the Benzegaggh-Kenane (B-K) [2] mode-dependent fracture energy interpolation law. Simulation of this impact test demonstrates a good match of experimental and simulations results in terms of panel deflection and panel-projectile interactions. The overall extent of delaminations was under-predicted by the simulation. This work forms the basis to model tests performed at higher velocities, involving projectile penetration of the panel.
INVESTIGATION OF BENDING AFTER IMPACT FAILURE BEHAVIOR IN FOAM-CORE HYBRID SANDWICH COMPOSITES AT EXTREME LOW TEMPERATURE
Authors: MIRZA FAIZAN , MACK JASON P. , BANIK ARNOB , KHAN M. H. , TAN K. T.
Published: November 2023

In this study, we investigate the behaviour of foam-core sandwich composites, specifically with regards to bending after impact (BAI), in the presence of carbon fiber reinforced polymer (CFRP) and/or glass fiber reinforced polymer (GFRP) facesheets. To accomplish this, we utilize an Instron 5582 universal testing machine to conduct 3- point bend test on specimens that have previously undergone impact testing. The 3-point bend tests are conducted at both room temperature (23°C) and low temperature (-70°C) to evaluate the effect of low temperature (LT) on the BAI behaviour of the composite materials. Moreover, we explore the effect of different stacking sequence and layup configuration of GFRP and CFRP layers on sandwich composites under flexural loading. We analyse the force-displacement curves and compare peak stress values to gain insight into the influence of the CFRP and GFRP hybrid facesheets. Results suggest that altering the arrangement of CFRP and GFRP layers has a significant impact on the flexural strength of the hybrid composite. At LT, the specimens experience more flexural damage due to increase in brittleness. However, the peak stress at LT increases due to the increase in the compressive strength of the CFRP layers. Specimens featuring a GFRP layer on the outside (referred to as ‘glass first’ specimens) and specimens with alternating CFRP/GFRP layers, with CFRP positioned on the outermost layers (referred to as ‘CGCG’), when impacted at 15J, experience core shear and core debonding at LT flexural test. Overall, GC is found to be the optimal configuration. This configuration provides excellent strength from the inner CFRP layer and while the outer GFRP layer offers damage resistance during impact test.
COMPARING CHARACTERIZATION METHODS FOR INVESTIGATING HIGH-TEMPERATURE BENDING BEHAVIOR OF MELTED THERMOPLASTIC PREPREG USING DMA AND RHEOMETER
Authors: CHASE GRIFFIN , OSTER LOGAN , ABRAMSON JON , LANE MALCOLM , FORGHANI ALIREZA , SALVIATO MARCO , ZOBEIRY NAVID
Published: November 2023

prepreg, a combination of pseudo-viscoelastic constitutive analysis and/or additional deformation measurement using a laser profiler were used. In comparison, the custom-built pure bending fixture in the rheometer was capable of directly measuring the moment-curvature at high temperatures for larger specimens to higher levels of curvature. It was shown that the 4-point bending method is an approximation as the new fixture cannot apply pure beam bending. Nevertheless, the results were found to be reliable and repeatable. Given the availability of DMA or rheometer, and the limitations of different test methods, the results of this study can be used as a guideline to characterize the bending behavior of thermoplastic composites.With the growing popularity of thermoplastic composites, controlling and optimizing processing methods, such as in-situ Automated Fiber Placement (AFP) consolidation or continuous compression molding (CCM), has become increasingly important. These methods involve melting and deforming materials at extreme conditions, followed by consolidation and autohesion. To control these processes, the thermo-mechanical behavior of viscoplastic materials at high temperatures, such as bending response, must be well understood. This understanding enables the use of process simulation to explore optimization of processing parameters. In this work, a new characterization technique for examining the bending behavior of thin-ply thermoplastic prepreg using Dynamic Mechanical Analysis (DMA) is developed and compared with a test method that uses a rheometer and was previously developed by Convergent. Toray TC1225 LM PAEK thermoplastic prepreg was used in both methods to study the bending-relaxation behavior of the material at different temperatures and loading rates. A standard 3-point bend fixture and a custom-built 4-point bend fixture were used for DMA testing, while a custom-built pure bending fixture was used for rheometer testing. Although the initial testing with the 3-point bend fixture was promising, limitations were found due to the variable bending moment across the beam and highest bending under the loading contact point, leading to micro-buckling and formation of plastic hinges in early deformations. This was mitigated by employing a custom-built 4-point bending fixture, which enabled pure bending in a larger section of the beam. For data reduction and analysis of viscoplastic moment-curvature of the
A FRAMEWORK FOR DESIGN ALLOWABLES ACCOUNTING FOR PAUCITY OF DATA AND ERRORS IN COMPLEX MODELS
Authors: HAWI PHILIPPE , YAO ZHENGTAO , AITHARAJU VENKAT , MAHISHI JAY , GHANEM ROGER
Published: November 2023

This work introduces a novel framework for the prediction of design allowables of composite laminates with reduced experimental cost. Building on high-fidelity simulations, polynomial chaos expansions (PCE) are first used to build probabilistic models for the material properties (input parameters). The coefficients of the models are themselves randomized by perturbing them with new stochastic degrees of freedom, thus accounting for uncertainty on the uncertainty and generating a family of distributions for these parameters. High-fidelity simulations are used to generate samples of the quantity of interest (QoI) which is then represented by a new PCE in terms of the previously described stochastic degrees of freedom. With this construction, the distribution of the QoI can be cheaply estimated and updated with experimental observations. The framework is applied to a hybrid carbon-glass fiber composite laminate under 3-point bending. We demonstrate how the updated distribution of the QoI can be used to predict the A-basis design allowable.
SUPERCRITICAL FLUID TREATMENTS OF FLAX FIBERS FOR IMPROVED MECHANICAL PROPERTIES
Authors: LANGHORST AMY , RIELAND JULIE , BANU MIHAELA , LOVE BRIAN , TAUB ALAN
Published: November 2023

Global increases in CO2 levels and increasing concerns regarding the effects of climate change have encouraged the transportation sector to reduce the carbon footprint of its products. The automotive and aerospace sectors have focused on the replacement of monolithic materials with composites, which have the potential to reduce weight and optimize the properties of the materials they are replacing. Many structural composites contain fiberglass reinforcement, which has a high density and is energy intensive to produce. Natural fibers have been explored as a low density, renewable alternative, but high variability and low mechanical properties have historically prevented widespread use of natural fibers in structural composites. In prior work, flax fibers treated under a specific set of conditions in supercritical CO2 (scCO2) were shown to improve fiber tensile properties. In this work, the dynamic mechanical properties of the fibers treated in scCO2 were evaluated. Treatment resulted in an increase in storage modulus, loss modulus, and tan-delta, consistent with reductions in fiber porosity and increases in fiber density previously reported. Additional treatments of the fibers in supercritical nitrogen (scN2) and supercritical argon (scAr) were explored to understand how the fluid chemistry may affect fiber structure and fiber mechanical properties. Fibers treated in scAr exhibited similar crystallinity and mechanical properties to fibers treated in scCO2 under the same conditions. However, fibers treated in scN2 exhibited higher crystallinity than fibers treated in scCO2 and scAr, but no significant changes to mechanical performance. Overall, this work expands the understanding on how supercritical fluid treatments could be applied to natural fibers as a means of enhancing fiber mechanical performance for composite applications.
DESIGN OPTIMIZATION TO FABRICATION WITH HYPERX LAMINATE FAMILIES FOR TRADITIONAL QUAD 0/45/90 AND DOUBLE-DOUBLE [±Φ/±Ψ] LAYUPS
Authors: BEDNARCYK BRETT A. , LI CARINA X. , JIN BO , NOEVERE AUGUST , COLLIER CRAIG
Published: November 2023

Traditional Quad and novel Double-Double laminate designs have been investigated using the HyperX design/optimization software for a panel with a large circular cutout. Parametric studies were performed based on varying the panel loading to compare the optimized masses of Quad and Double-Double designs for a uniform panel, a panel with a single buildup region around the cutout, and a fully optimized panel where the thickness and layup are varied throughout the panel. Finally, following the same optimization procedures in HyperX, a Quad demonstration test panel was designed and manufactured via hand layup and vacuum infusion.
Atraumatic Calcific Tendinitis in Medial Collateral Ligament: A Case Report
Authors:   Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia, United States., Berry Carter J , Tagliero Adam J ,   Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia, United States., Diduch David R ,   Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia, United States.
Published: November 2023

Introduction: Calcific tendinitis is a commonly treated in the shoulder and wrist, but it is rarely seen in the medial collateral ligament (MCL). There is not satisfactory orthopedic literature for diagnosis and treatment of this condition. Case Report: A healthy 50-year-old woman presented with medial sided right knee pain. She did not have any history of trauma to the knee nor instability. She was diagnosed with calcific tendinitis of her MCL and was treated with US-guided lavage. This was her 4th documented location of symptomatic calcific tendinitis including her right shoulder, left wrist, and contralateral knee MCL. Conclusions: We present a case of a 50-year-old female with a history of multifocal, symptomatic calcific tendinitis, who had atraumatic mineral deposition in her MCL. Ultrasound-guided lavage is a successful minimally invasive treatment for calcific tendinitis. Keywords: Medial collateral ligament, calcific tendinitis, hydroxyapatite, knee.
Intelligent-reflecting-surfaces-assisted hybrid FSO/RF communication with diversity combining: a performance analysis
Authors: Uniyal Smriti , Vishwakarma Narendra , Swaminathan R. , Madhukumar A. S.
Published: November 2023

Free space optics (FSO) and radio frequency (RF) communication systems
exhibit complementary characteristics, with FSO being susceptible to
fog, turbulence, and pointing errors, whereas RF is susceptible to
rain and small scale fading. These inherent complementary
characteristics between FSO and RF communication systems enable the
hybrid configuration to effectively alleviate the impact of
environmental impediments. This paper presents the performance
analysis of an intelligent reflecting surfaces (IRSs)-assisted hybrid
FSO/RF system under atmospheric turbulence (AT), pointing errors (PE),
small scale fading effects, and attenuation due to climatic conditions
such as fog, rain, etc. To characterize the AT, gamma–gamma
distribution is used, and the multipath fading in the RF link is
modeled using Nakagami-m distribution. At the receiver,
signals from both the FSO and RF links are combined using either the
selection combining (SC) or maximal-ratio combining (MRC) technique.
We derive the exact closed-form expressions for outage probability and
average symbol error rate (ASER) for both diversity combining schemes.
The proposed system is compared with the direct link (DL) FSO system,
IRSs-assisted FSO system, and hybrid FSO/RF system with diversity
combining schemes. Further, the performance comparison between the SC
and MRC schemes is also reported. Finally, the accuracy of the
analytical expressions is verified by utilizing Monte Carlo
simulations.
Potential vision tester using adaptive optics, Maxwellian view, and small pupil
Authors: Elsner Ann E. , Papay Joel A. , Parimi Vamsi , Jung Hae Won , Clark Christopher A. , Burns Stephen A. , Gast Thomas J.
Published: November 2023

We demonstrate a free-space, trolley-mounted potential vision tester (PVT), designed to study and improve the accuracy of visual acuity (VA) measurements in the aging eye. Key features include a high-resolution visual display presented in Maxwellian view, a 3 mm pupil to limit wavefront (WF) aberrations, and a moderate cost deformable mirror to induce or correct higher order optical aberrations. The visual display supported accurate measurement of visual acuities down to 20/5. The moderate cost, piezo deformable mirror induced seven nominal aberrations, calibrated as 0, -0.32, -0.23, + 0.27, and +0.39 microns spherical aberration; + 0.49 microns Y coma; and -0.51 microns X coma. A custom Hartmann Shack (HS) calibration (HSc) system demonstrated that induced aberrations were repeatable and stable. A Badal optometer provided the coarse focus. WF aberrations were measured for five normal subjects with a commercially available HS device (HSP) (OCULUS Pentacam AXL Wave), providing estimates of WF errors for 3 mm and other pupil sizes. VA was measured using four alternative forced-choice for a single black on white E stimulus in each trial. Using the method of constant stimuli yielded robust standard deviation measurements. The 50% fit for VA plotted against induced aberration resulted in linear functions for each subject for the range of our positive and negative spherical aberration data. Subjects differed, but higher order terms were unnecessary to describe data across spherical aberrations.
Machine learning for self-tuning mode-locked lasers with multiple transmission filters
Authors: Bağcı Mahmut , Kutz J. Nathan
Published: November 2023

We develop an adaptive control and self-tuning procedure for mode-locked fiber laser systems using multiple transmission filters. Each transmission filter set consists of two quarter-wave plates, a passive polarizer, and a half-wave plate to generate nonlinear polarization rotation (NPR). The energy performance of a fiber laser can be significantly increased by incorporating multiple NPR filters. Critical for self-tuning is the ability to properly characterize the average cavity birefringence, and, although the existed self-tuning algorithms can successfully classify the birefringence of single filter configuration, they cannot achieve real-time recognition of the cavity birefringence for multifilter laser systems. To remedy this issue, we propose three birefringence classification algorithms based upon learned libraries of observed dynamic patterns, including a uniform, a hierarchical, and a dynamic selection procedure from such patterns. A maximum seeking algorithm is then constructed to determine the optimal (maximal) wave plate(s) and polarizer(s) settings. Thus, the adaptive control and self-tuning scheme is designed as a combination of maximum seeking and dynamic library selection algorithms. Numerical implementation shows that the proposed self-tuning scheme achieves stable, high-energy mode-locking while circumventing the multipulsing instability.
Molecular alignment-assisted spectral broadening and shifting in the near-infrared with a recycled depleted pump from an optical parametric amplifier
Authors: Rodnova Zhanna , Saule Tobias , Gibson George , Trallero-Herrero Carlos A.
Published: November 2023

We demonstrate how the depleted pump of an optical parametric amplifier can be recycled for impulsive alignment of a molecular gas inside a hollow-core fiber and use such alignment for the broadening and frequency shift of the signal pulse at a center wavelength of ∼1300 nm. Our results combine non-adiabatic molecular alignment, self-phase modulation, and Raman non-linearities. We demonstrate spectral shifts of up to 204 nm and a spectral broadening of more than one octave. We also report on the time delays at which broadening occurs, which do not coincide with any of the molecular rotational constants. Further, we encounter that maximum frequency shifts occur when the signal and pump have perpendicular polarization instead of parallel.
Quantitative comparison of the computational complexity of optical, digital and hybrid neural network architectures for image classification tasks
Authors: Chen Mengxiang , Schoenhardt Steffen , Gu Min , Goi Elena
Published: November 2023

By implementing neuromorphic paradigms in processing visual information, machine learning became crucial in an ever-increasing number of applications of our everyday lives, ever more performing but also computationally demanding. While a pre-processing of the information passively in the optical domain, before optical-electronic conversion, can reduce the computational requirements for a machine learning task, a comprehensive analysis of computational requirements for hybrid optical-digital neural networks is thus far missing. In this work we critically compare and analyze the performance of different optical, digital and hybrid neural network architectures with respect to their classification accuracy and computational requirements for analog classification tasks of different complexity. We show that certain hybrid architectures exhibit a reduction of computational requirements of a factor >10 while maintaining their performance. This may inspire a new generation of co-designed optical-digital neural network architectures, aimed for applications that require low power consumption like remote sensing devices.
Surface plasmon resonance sensor based on polarization parameter SPR imaging
Authors: Che Zheng , Hou Jamie Jiangmin , Hou Lianping , Ni Bin , Liu Xuefeng , Xu Bin , Xiong Jichuan
Published: November 2023

Using polarization surface plasmon resonance (SPR) imaging as a sensor has the advantage of large throughput in detection, but its sensitivity has always been inferior to other SPR sensors. The high contrast of the two polarization parameters’ images related to scattering determines the high sensitivity of this new polarization SPR imaging sensor. It provides a new direction for solving the issue of low sensitivity in polarization SPR imaging. The sensor system was optimized by numerical simulation, whilst the baseline noise and sensitivity of the system were obtained by saline solution and virus detection. When the reflective index of the NaCl solution is within the range of 1.3331 to 1.36, the average sensitivity can reach 9300 RIU-1, and the maximum sensitivity can reach 13000 RIU-1. Using this new polarization SPR imaging sensor, the H1N1 virus was differentiated, showing its promising application potential within the field of biomedicine.