bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering of global transcription factor FruR to redirect the carbon flow in Escherichia coli for enhancing l-phenylalanine biosynthesis
Authors: Chen Minliang , Liang Hengyu , Han Chao , Zhou Peng , Xing Zhiwei , Chen Qianqian , Liu Yongyu , Xie Gou-an , Xie Rufei
Published: October 2022

Background

The catabolite repressor/activator protein (FruR) is a global regulatory protein known to control the expression of several genes concerned with carbon utilization and energy metabolism. This study aimed to illustrate effects of the FruR mutant on the L-phenylalanine (L-PHE) producing strain PHE01.

Results

Random mutagenesis libraries of fruR generated in vitro were first integrated into the chromosome of PHE01 by CRISPR/Cas9 technique, and then the best mutant PHE07 (FruRE173K) was obtained. With this mutant, a final L-PHE concentration of 70.50 ± 1.02 g/L was achieved, which was 23.34% higher than that of PHE01. To better understand the mechanism, both transcriptomes and metabolomes of PHE07 were carried out and compared to that of PHE01. Specifically, the transcript levels of genes involved in gluconeogenesis pathway, pentose phosphate pathway, Krebs cycle, and glyoxylate shunt were up-regulated in the FruRE173K mutant, whereas genes aceEF, acnB, and icd were down-regulated. From the metabolite level, the FruRE173K mutation led to an accumulation of pentose phosphate pathway and Krebs cycle products, whereas the products of pyruvate metabolism pathway: acetyl-CoA and cis-aconic acid, were down-regulated. As a result of the altered metabolic flows, the utilization of carbon sources was improved and the supply of precursors (phosphoenolpyruvate and erythrose 4-phosphate) for L-PHE biosynthesis was increased, which together led to the enhanced production of L-PHE.

Conclusion

A novel strategy for L-PHE overproduction by modification of the global transcription factor FruR in E. coli was reported. Especially, these findings expand the scope of pathways affected by the fruR regulon and illustrate its importance as a global regulator in L-PHE production.
The impact of the COVID-19 pandemic on harm reduction services in Catalonia: the experience of people who use drugs and harm reduction professionals
Authors: Bosch-Arís Mar , Gasulla Laia , de Gispert Teresa , Segura Lidia , Colom Joan
Published: October 2022

Background

Harm reduction services and professionals have had to reorganise and adapt to COVID-19 prevention measures while still ensuring health and social services for people who use drugs (PUD).

Objective

To assess the impact of the COVID-19 pandemic on PUD and on the professionals who provide harm reduction services.

Methods

A qualitative, exploratory, multicentre design was used. Two focus groups were held with harm reduction professionals, and 40 individual semi-structured interviews were undertaken with PUD in various harm reduction services in Catalonia. Interviews and focus group discussions were transcribed and analysed using thematic content analysis.

Results

Harm reduction services adapted to the pandemic situation by employing methods such as reducing opening hours and closing drop in areas, along with health protection measures such as access control, which in turn led to stress among both professionals and service users. Despite the changes implemented, PUD continued to have access to sterile drug use equipment and methadone treatment. In addition, those who were not in treatment were able to access it rapidly. Regarding their emotional state, the PUD reported that it was worse during the pandemic than before the lockdown, with women affected to a greater extent than men. The harm reduction professionals reported difficulties in managing service users’ compliance with the security measures at the beginning of the lockdown and having had to focus primarily on providing food and shelter for the PUD.

Conclusions

It is important to keep PUD in mind and maintain a harm reduction perspective when implementing confinement measures in situations such as those experienced during the COVID pandemic. Guaranteeing that PUD have their basic needs such as food, hygiene and shelter covered is key.
Concanavalin A as a promising lectin-based anti-cancer agent: the molecular mechanisms and therapeutic potential
Authors: Huldani Huldani , Rashid Ahmed Ibraheem , Turaev Khikmatulla Negmatovich , Opulencia Maria Jade Catalan , Abdelbasset Walid Kamal , Bokov Dmitry Olegovich , Mustafa Yasser Fakri , Al-Gazally Moaed E. , Hammid Ali Thaeer , Kadhim Mustafa M. , Ahmadi Seyed Hossein
Published: October 2022

Concanavalin A (ConA), the most studied plant lectin, has been known as a potent anti-neoplastic agent for a long time. Since initial reports on its capacity to kill cancer cells, much attention has been devoted to unveiling the lectin's exact molecular mechanism. It has been revealed that ConA can bind to several receptors on cancerous and normal cells and modulate the related signaling cascades. The most studied host receptor for ConA is MT1-MMP, responsible for most of the lectin's modulations, ranging from activating immune cells to killing tumor cells. In this study, in addition to studying the effect of ConA on signaling and immune cell function, we will focus on the most up-to-date advancements that unraveled the molecular mechanisms by which ConA can induce autophagy and apoptosis in various cancer cell types, where it has been found that P73 and JAK/STAT3 are the leading players. Moreover, we further discuss the main signaling molecules causing liver injury as the most significant side effect of the lectin injection. Altogether, these findings may shed light on the complex signaling pathways controlling the diverse responses created via ConA treatment, thereby modulating these complex networks to create more potent lectin-based cancer therapy.
Single-cell RNA sequencing reveals a landscape and targeted treatment of ferroptosis in retinal ischemia/reperfusion injury
Authors: Li Yangyang , Wen Yuwen , Liu Xiuxing , Li Zhuang , Lin Bingying , Deng Caibin , Yu Ziyu , Zhu Yingting , Zhao Ling , Su Wenru , Zhuo Yehong
Published: October 2022

Background

The aim of this study was to establish a complete retinal cell atlas of ischemia–reperfusion injury by single-cell RNA sequencing, and to explore the underlying mechanism of retinal ischemia–reperfusion injury in mice.

Methods

Single-cell RNA sequencing was used to evaluate changes in the mouse retinal ischemia reperfusion model. In vivo and in vitro experiments were performed to verify the protective effect of inhibiting ferroptosis in retinal ischemia–reperfusion injury.

Results

After ischemia–reperfusion injury, retinal cells were significantly reduced, accompanied by the activation of myeloid and a large amount of blood-derived immune cell infiltration. The IFNG, MAPK and NFKB signaling pathways in retinal neuronal cells, together with the TNF signaling pathway in myeloid give rise to a strong inflammatory response in the I/R state. Besides, the expression of genes implicating iron metabolism, oxidative stress and multiple programed cell death pathways have changed in cell subtypes described above. Especially the ferroptosis-related genes and blocking this process could apparently alleviate the inflammatory immune responses and enhance retinal ganglion cells survival.

Conclusions

We established a comprehensive landscape of mouse retinal ischemia–reperfusion injury at the single-cell level, revealing the important role of ferroptosis during this injury, and targeted inhibition of ferroptosis can effectively protect retinal structure and function.
Targeting ERRα promotes cytotoxic effects against acute myeloid leukemia through suppressing mitochondrial oxidative phosphorylation
Authors: Seo Wonhyoung , Yoo Seungyeul , Zhong Yi , Lee Sang-Hee , Woo Soo-Yeon , Choi Hee-Seon , Won Minho , Roh Taylor , Jeon Sang Min , Kim Kyeong Tae , Silwal Prashanta , Lee Min Joung , Heo Jun Young , Lawlor Nathan , Kim Sup , Lee Dongjun , Kim Jin-Man , Song Ik-Chan , Zhu Jun , Jo Eun-Kyeong
Published: October 2022

Acute myeloid leukemia (AML) is an aggressive blood cancer with poor clinical outcomes. Emerging data suggest that mitochondrial oxidative phosphorylation (mtOXPHOS) plays a significant role in AML tumorigenesis, progression, and resistance to chemotherapies. However, how the mtOXPHOS is regulated in AML cells is not well understood. In this study, we investigated the oncogenic functions of ERRα in AML by combining in silico, in vitro, and in vivo analyses and showed ERRα is a key regulator of mtOXPHOS in AML cells. The increased ERRα level was associated with worse clinical outcomes of AML patients. Single cell RNA-Seq analysis of human primary AML cells indicated that ERRα-expressing cancer cells had significantly higher mtOXPHOS enrichment scores. Blockade of ERRα by pharmacologic inhibitor (XCT-790) or gene silencing suppressed mtOXPHOS and increased anti-leukemic effects in vitro and in xenograft mouse models.
Acute perchloroethylene intoxication in an elderly woman: a case report
Authors: Tarditi Alessandro , Montalbano Leda , Spina Stefano , Marrazzo Francesco , Casella Giampaolo , Schenardi Paolo , Conti Tommaso , Angeli Ilaria , Minoli Mauro , Fumagalli Roberto , Langer Thomas
Published: October 2022

Background

Perchloroethylene is a colorless, strong-smelling substance commonly used for dry cleaning. Liver and kidney toxicities and carcinogenicity are well-known occupational hazards caused by chronic perchloroethylene exposure. Acute intoxication by ingestion of nondiluted perchloroethylene is rare in the adult population owing to its strong smell and taste. Very few data are available to physicians managing patients in this situation.

Case presentation

An 89-year-old Caucasian woman accidentally drank perchloroethylene while visiting her laundry, leading to a coma within a few minutes. The poison control center provided little information about perchloroethylene toxicity after ingestion, including an estimated long biological half-life (144 hour) and detrimental effects to liver and kidneys. A long intensive care unit stay was thus expected, potentially leading to several complications. After intubation, transitory hypoxemia appeared and rapidly resolved, while mild hemodynamic instability was managed with fluid resuscitation and anti-arrhythmic drugs. Twelve hours after perchloroethylene ingestion, the patient suddenly woke up and self-extubated. Less than 24 hours after ingestion, she was discharged from the intensive care unit, and 4 days later she was discharged home.

Conclusion

The patient drank perchloroethylene from a bottle, which prevented her from smelling it, and owing to its taste, only a small sip was likely drunk. However, a much larger intake was presumed, given her rapid and profound central nervous system depression. This case was challenging owing to the paucity of information available regarding acute perchloroethylene ingestion and the duration and magnitude of its effect. The present report will hopefully be of support for clinicians managing patients with this rare acute intoxication.
Screening for prostate cancer: protocol for updating multiple systematic reviews to inform a Canadian Task Force on Preventive Health Care guideline update
Authors: Bennett Alexandria , Beck Andrew , Shaver Nicole , Grad Roland , LeBlanc Allana , Limburg Heather , Gray Casey , Abou-Setta Ahmed , Klarenbach Scott , Persaud Navindra , Thériault Guylène , Thombs Brett D. , Todd Keith J. , Bell Neil , Dahm Philipp , Loblaw Andrew , Del Giudice Lisa , Yao Xiaomei , Skidmore Becky , Rolland-Harris Elizabeth , Brouwers Melissa , Little Julian , Moher David
Published: October 2022

Purpose

To inform updated recommendations by the Canadian Task Force on Preventive Health Care on screening for prostate cancer in adults aged 18 years and older in primary care. This protocol outlines the planned scope and methods for a series of systematic reviews.

Methods

Updates of two systematic reviews and a de novo review will be conducted to synthesize the evidence on the benefits and harms of screening for prostate cancer with a prostate-specific antigen (PSA) and/or digital rectal examination (DRE) (with or without additional information) and patient values and preferences. Outcomes for the benefits of screening include reduced prostate cancer mortality, all-cause mortality, and incidence of metastatic prostate cancer. Outcomes for the harms of screening include false-positive screening tests, overdiagnosis, complications due to biopsy, and complications of treatment including incontinence (urinary or bowel), and erectile dysfunction. The quality of life or functioning (overall and disease-specific) and psychological effects outcomes are considered as a possible benefit or harm. Outcomes for the values and preferences review include quantitative or qualitative information regarding the choice to screen or intention to undergo screening. For the reviews on benefits or harms, we will search for randomized controlled trials, quasi-randomized, and controlled studies in MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials. For the review on values and preferences, we will search for experimental or observational studies in MEDLINE, Embase, and PsycInfo. For all reviews, we will also search websites of relevant organizations, gray literature, and reference lists of included studies. Title and abstract screening, full-text review, data extraction, and risk of bias assessments will be completed independently by pairs of reviewers with any disagreements resolved by consensus or by consulting with a third reviewer. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach will be used to assess the certainty of the evidence for each outcome.

Discussion

The series of systematic reviews will be used by the Canadian Task Force on Preventive Health Care to update their 2014 guideline on screening for prostate cancer in adults aged 18 years and older.

Systematic review registration

This review has been registered with PROSPERO (CRD42022314407) and is available on the Open Science Framework (osf.io/dm32k).
DUSP5 and PHLDA1 mutations in mature cystic teratomas of the ovary identified on whole-exome sequencing may explain teratoma characteristics
Authors: Wang Wen-Chung , Lai Yen-Chein
Published: October 2022

Background

Mature cystic teratomas of the ovary are the most common type of germ cell tumor, comprising 33% of ovarian tumors. Studying these tumors may result in a better understanding of their stepwise developmental processes and molecular bases and provide useful information for the development of tissue-engineering technologies.

Methods

In the present study, 9 mature cystic teratomas of the ovary were analyzed by whole-exome sequencing and the results were compared with the Catalogue of Somatic Mutations in Cancer and dbSNP databases.

Results

Mutations were validated in 15 genes with alterations in all 9 (100%) samples and changes in protein coding. The top 10 mutated genes were FLG, MUC17, MUC5B, RP1L1, NBPF1, GOLGA6L2, SLC29A3, SGK223, PTGFRN, and FAM186A. Moreover, 7 variants in exons with changes in protein coding are likely of importance in the development of mature cystic teratomas of the ovary, namely PTGFRN, DUSP5, MPP2, PHLDA1, PRR21, GOLGA6L2, and KRTAP4-2.

Conclusions

These genetic alterations may play an important etiological role in teratoma formation. Moreover, novel mutations in DUSP5 and PHLDA1 genes found on whole-exome sequencing may help to explain the characteristics of teratomas.
Non-clinical safety evaluation of salvianolic acid A: acute, 4-week intravenous toxicities and genotoxicity evaluations
Authors: Yang Ming-Yan , Song Ze-Yu , Gan Hai-Lin , Zheng Mei-Hua , Liu Qian , Meng Xiang-Ting , Pan Tao , Li Zhen-Yuan , Peng Ruo-Xuan , Liu Ke , Fan Hua-Ying
Published: October 2022

Background

Toxicological problem associated with herbal medicine is a significant public health problem. Hence, it is necessary to elaborate on the safety of herbal medicine. Salvianolic acid A (SAA) is a major active compound isolated from Danshen, a popular herbal drug and medicinal food plant in China. The aim of the present study was to explore the toxicological profile of SAA.

Methods

The acute toxicity studies were performed in mice and Beagle dogs with single administration with SAA. A 4-week subchronic toxicity was test in dogs. SAA was intravenously administered at doses of 20, 80 and 300 mg/kg. Clinical observation, laboratory testing and necropsy and histopathological examination were performed. The genotoxic potential of SAA was evaluated by 2 types of genotoxicity tests: a reverse mutation test in bacteria and bone marrow micronucleus test in mice.

Results

In acute toxicities, the LD50 of SAA is 1161.2 mg/kg in mice. The minimum lethal dose (MLD) and maximal non-lethal dose (MNLD) of SAA were 682 mg/kg and 455 mg/kg in dogs, respectively. The approximate lethal dose range was 455–682 mg/kg. In the study of 4-week repeated-dose toxicity in dogs, focal necrosis in liver and renal tubular epithelial cell, the decrease in relative thymus weight, as well as abnormal changes in biochemical parameters, were observed in SAA 80 or 300 mg/kg group. The no observed adverse effect level (NOAEL) of SAA was 20 mg/kg. Thymus, liver and kidneys were the toxic targets. These toxic effects were transient and reversible. These results indicated that it should note examination of liver and kidney function during the administration of SAA in clinic. Furthermore, SAA had no mutagenic effect at any tested doses.

Conclusion

These results provide new toxicological information of SAA for its clinical application and functional food consumption.
Fractures of limbs specific to children: the experience of a Senegalese tertiary hospital
Authors: Zeng Florent Tshibwid A , Fall Mbaye , Mbaye Papa Alassane , Gueye Doudou , Bisseyou Audrey Kongo , Seck Ndeye Fatou , Camara Souleymane , Wellé Ibrahima Bocar , Diedhiou Youssouph , Ndoye Ndeye Aby , Sagna Aloïse , Ndour Oumar , Ngom Gabriel
Published: October 2022

Introduction

Fractures specific to the pediatric age group represent a particular injury due to their pattern, diagnosis, management, and outcomes. In sub-Saharan Africa, studies on this particular injury are scarce. This study reports sociodemographic, diagnostic, and therapeutic aspects and outcomes of these fractures.

Methods

We conducted a descriptive cross sectional study at the pediatric surgery department of Aristide Le Dantec University Teaching Hospital in Dakar, Senegal, from January 2012 to December 2015.

Results

A fracture specific to children was diagnosed in 180, of whom 47.7% were school-aged, with 59.4% of males. The mean time from injury to the attendance of our department was 48.2 h. Domestic accidents occurred in 51.1%. A total of 243 fractures occurred, mainly on the upper limbs (75.3%), as the most affected bones were the radius (47.3%), ulna (22.6%), and tibia (13.6%). Greenstick fractures represented 46.9%, buckle fractures, 42.8%, plastic deformations 9%, and subperiosteal fractures 0.7%. In all patients, management was orthopedic, with associated analgesic treatment. No sequel nor other complication was registered.

Conclusion

Fractures proper to the child are a particular entity in children’s trauma, frequently happening in boys, with greenstick and buckle fractures being the most common. Their treatment is exclusively orthopedic, with excellent outcomes.
Fault detection using a convolutional neural network trained with point-spread function-convolution-based samples
Authors: Jing Jiankun , Yan Zhe , Zhang Zheng , Gu Hanming , Han Bingkai
Published: October 2022

Automatic fault detection in seismic images using deep learning-based methods has attracted great interest in recent years. Detecting faults by deep learning methods is generally considered a supervised learning task, which requires numerous diverse training samples and corresponding accurate labels. Because field data with faults labeled by experienced interpreters are difficult to acquire, training samples are usually generated synthetically, in which the 1D seismic wavelets are convolved with reflectivity models. However, the 1D-convolution-based synthetic seismic images still differ from the real seismic images. Therefore, the network trained by such samples may fail to detect some faults in the field data. Full-wavefield approaches are the optimal seismic modeling methods, but they cannot be widely used at present due to the high cost. In this paper, we present an efficient approach to generate realistic synthetic seismic images by using a point-spread function (PSF)-based convolution. Because the size of a seismic sample used for deep learning training is a small range relative to the field seismic data, assuming the background velocity is close to homogeneous in such a small range, we can efficiently construct the PSF using the analytical Green’s function. With an Intel Core i9-10900K CPU, the PSF approach takes approximately 15 min to generate a seismic image of size 128 × 128 × 128, whereas it takes approximately 20 h to generate a seismic image of the same size using reverse time migration. The examples of one synthetic image and two field seismic images demonstrate that the network trained with the PSF convolution samples can predict more accurate and continuous faults than that trained with the 1D convolution samples.
Electronic Nicotine Delivery Systems: An Updated Policy Statement From the American Association for Cancer Research and the American Society of Clinical Oncology
Authors: Herbst Roy S. , Hatsukami Dorothy , Acton Dana , Giuliani Meredith , Moushey Allyn , Phillips Jonathan , Sherwood Shimere , Toll Benjamin A. , Viswanath Kasisomayajula , Warren Nicholas J.H. , Warren Graham W. , Alberg Anthony J.
Published: October 2022

Combustible tobacco use has reached historic lows, demonstrating the importance of proven strategies to reduce smoking since publication of the 1964 Surgeon General's report. In contrast, the use of electronic nicotine delivery systems (ENDS), specifically e-cigarettes, has grown to alarming rates and threatens to hinder progress against tobacco use. A major concern is ENDS use by youth and adults who never previously used tobacco. While ENDS emit fewer carcinogens than combustible tobacco, preliminary evidence links ENDS use to DNA damage and inflammation, key steps in cancer development. Furthermore, high levels of nicotine can also increase addiction, raise blood pressure, interfere with brain development, and suppress the immune system. The magnitude of long-term health risks will remain unknown until longitudinal studies are completed. ENDS have been billed as a promising tool for combustible tobacco cessation, but further evidence is needed to assess their potential efficacy for adults who smoke. Of concern, epidemiological studies estimate that approximately 15%-42% of adults who use ENDS have never used another tobacco product, and another 36%-54% dual use both ENDS and combustible tobacco. This policy statement details advances in science related to ENDS and calls for urgent action to end predatory practices of the tobacco industry and protect public health. Importantly, we call for an immediate ban on all non–tobacco-flavored ENDS products that contain natural or synthetic nicotine to reduce ENDS use by youth and adults who never previously used tobacco. Concurrently, evidence-based treatments to promote smoking cessation and prevent smoking relapse to reduce cancer incidence and improve public health remain top priorities for our organizations. We also recognize there is an urgent need for research to understand the relationship between ENDS and tobacco-related disparities.
Revisiting the significance of keratin expression in complex epithelia
Authors: Cohen Erez , Johnson Craig , Redmond Catherine J. , Nair Raji R. , Coulombe Pierre A.
Published: October 2022

A large group of keratin genes (n=54 in the human genome) code for intermediate filament (IF)-forming proteins and show differential regulation in epithelial cells and tissues. Keratin expression can be highly informative about the type of epithelial tissue, differentiation status of constituent cells and biological context (e.g. normal versus diseased settings). The foundational principles underlying the use of keratin expression to gain insight about epithelial cells and tissues primarily originated in pioneering studies conducted in the 1980s. The recent emergence of single cell transcriptomics provides an opportunity to revisit these principles and gain new insight into epithelial biology. Re-analysis of single-cell RNAseq data collected from human and mouse skin has confirmed long-held views regarding the quantitative importance and pairwise regulation of specific keratin genes in keratinocytes of surface epithelia. Furthermore, such analyses confirm and extend the notion that changes in keratin gene expression occur gradually as progenitor keratinocytes commit to and undergo differentiation, and challenge the prevailing assumption that specific keratin combinations reflect a mitotic versus a post-mitotic differentiating state. Our findings provide a blueprint for similar analyses in other tissues, and warrant a more nuanced approach in the use of keratin genes as biomarkers in epithelia.
The Psychosocial Value of Employment: Evidence from a Refugee Camp
Authors: Hussam Reshmaan , Kelley Erin M. , Lane Gregory , Zahra Fatima
Published: October 2022

Employment may be important to well-being for reasons beyond its role as an income source. This paper presents a causal estimate of the psychosocial value of employment in refugee camps in Bangladesh. We involve 745 individuals in a field experiment with three arms: a control arm, a weekly cash arm, and an employment arm of equal value. Employment raises psychosocial well-being substantially more than cash alone, and 66 percent of the employed are willing to forgo cash payments to continue working temporarily for free. Despite material poverty, those in our context both experience and recognize a nonmonetary, psychosocial value to employment. (JEL C93, D91, I31, J15, J22, O15)
Η οικονομική αυτάρκεια στην Ελληνική κοινωνία
Authors: Σταθάκου Αικατερίνη
Published: October 2022

Η «οικονομική αυτάρκεια» μέσα στην αταξία του μεσοπόλεμου, διατυπώνεται ως δόγμα «διακυβέρνησης» για το «επίπεδο ζωής», τους «εθνικούς πόρους». τον «επιχώριο πολιτισμό». Είναι η περίοδος συσσώρευσης ιδεών και πολιτικών από τον προηγούμενο αιώνα, για να αποδοθεί στην «αυτάρκεια» νέα διάσταση, από το δεύτερο μισό του 20ου αιώνα, στον 21ο αιώνα. Η «μελέτη περίπτωσης» των ιδεών και πρακτικών της «οικονομικής αυτάρκειας» και των επάλληλων εννοιών, αναζητήθηκε σε έναν τουλάχιστον εθνικό χώρο: την Ελληνική κοινωνία και οικονομία μεταξύ 1919 και 1939. Ο σκοπός να επανεξετασθεί η οικονομική αυτάρκεια μέσα από την εξέλιξη των κοινωνιολογικών ιδεών, τη χρήση των εννοιών «εντός» και «εκτός» οικονομικής λογικής αλλά και να αναζητήσει έναν τρόπο να επανατοποθετηθεί σήμερα στο χώρο της κοινωνιολογίας. Η έρευνα επικεντρώθηκε στην ανάλυση οικονομικών (κύριων και συμπληρωματικών) ιδεών και πρακτικών της μεσοπολεμικής οικονομικής πολιτικής αυταρχικών καθεστώτων. Η πολιτική της αυτάρκειας αναλύεται στο πνεύμα της «αυταρχίας» και τη χρήση της στο ευρύ πεδίο πολιτικών ιδεών, όπως ο παραδοσιακός συντηρητισμός, αλλά και την παύση της εξάρτησης ή της αλληλοβοήθειας για ένα κράτος από άλλες χώρες ή ομάδες χωρών.
Hybrid AC/DC architecture in the CE.D.E.R.-CIEMAT microgrid: demonstration of the TIGON project
Authors: Peña-Carro Paula , Izquierdo-Monge Oscar
Published: October 2022

This article presents the demonstrative development of the Towards Intelligent DC-based hybrid Grids Optimizing the Network performance (TIGON) project at the Centre for the Development of Renewable Energy - Centre for Energy, Environmental and Technological Research (CE.D.E.R.-CIEMAT), as well as the established objectives to be achieved with the implementation of a microgrid with smart grid architecture based on direct current (DC) and integrated into the current energy system. This type of architecture is proposed as a future solution to reduce energy losses caused by DC-alternating current (AC) conversions, increasing the overall performance and profitability of hybrid grids. All this without forgetting to ensure the supply, stability and reliability of the system with the development of all the necessary equipment and protections to make this approach a reality. The microgrid design and process of implementation start from a transformation centre, from which the medium voltage direct current (MVDC) grid will be created by the solid-state transformer (SST). In the MVDC grid, we will find a bank of lead-acid batteries and other essential equipment in the microgrid, a DC/DC converter that will create the low voltage direct current (LVDC) grid. On the LVDC side, several branches have been designed to connect the rest of the systems: generation (mini-wind and photovoltaic), storage (lithium ferro-phosphate [LFP] batteries) and loads (AC and DC loads). Each of the equipment will have a connection to the DC grid through converters made exclusively for this equipment and connexion to the AC grid, which will allow us to obtain all the necessary data to carry out the required studies to achieve the established objectives of the project.
Opiliofauna (Arachnida, Opiliones) de campos de Altitude no município de Poços de Caldas, Minas Gerais, Brasil
Authors: Pádua Thiago Henrique dos Reis , Rubim Luis Gustavo Talarico , Santos Mireile Reis dos , Souza Marcos Magalhães de
Published: October 2022

Há carência de estudos de inventários sobre opiliões em campos de altitude no Brasil, portanto, o presente trabalho objetivou ampliar informações sobre a opiliofauna desse ecossistema no município de Poços de Caldas, Minas Gerais. As coletas foram realizadas no período noturno, com quatro campanhas entre os meses de novembro de 2020 a março de 2021, totalizando 16 dias com 48 horas de esforço amostral. Foram coletadas quatro espécies e uma morfoespécie, que somam dois novos registros para a região, Mischonys squalidus Bertkau (Opiliones: Gonyleptidae) e Sclerosomatidae gen. sp. 1, ampliando a fauna de opiliões em campos de altitude do município para 11 espécies e uma morfoespécie.
Contemporary approach to online education at the medical school applying Socratic seminar or Socratic circle to lecturing
Authors: Shumilina K. , Kornienko S. , Lapshin D. , Vastyanov R.
Published: October 2022

We have sought the answer to a problem of online education introduced by COVID-19 pandemic. We suppose online education is to be the most dynamic form of professional learning which takes place at a distance with the use of effective informational and communicative tools. Our objective was to be focused on solving specific professional issues, to create conditions for effective learning based on our professional experience, with its maximum use. Socratic Dialogue is a brand that symbolizes the improvement of the quality of thinking in clarifying and solving problems in questioning in the community. Socratic seminars are one of the pedagogical technologies that provide the opportunity for students to actively practice in a wide variety of academic and professional skills. Its systematic procedure is used to examine a text through questions and answers founded on the beliefs that all new knowledge is connected to prior knowledge, that all thinking comes from asking questions, and that asking one question should lead to asking further questions. The goal of this study was to have participants work together, seek and gain deeper understanding of concepts in the text through thoughtful dialogue rather than memorizing information that has been provided for them. Our focus was to explore multiple perspectives on a given issue or top and student’s decision-making for the clinical cases provided. The method has helped us to identify students which lack any concrete knowledge or are not able to implement theoretical knowledge into solving practical tasks. The method also improved creative and critical and clinical thinking of the students who were actively engaged in the process not only during the class but also by preparing effectively for the class. We prioritized flexibility, individualization of learning, and put emphasis on self-study of the students. The authors voluntary move away from the truly philosophical direction in the introduction of Socratic dialogue into the methodology of modern teaching students in medical and biological disciplines and implement this learning option as an auxiliary one in online learning. Finally, authors analyzing the efficacy of a new teaching methodology in which the initiative of the conversation, its directions and possible branches from the original premise are provided to the students themselves.
Relacja między filozofią a retoryką w koncepcji Giovanniego Pico della Mirandoli
Authors: Krupecka Iwona
Published: October 2022

Artykuł stanowi próbę analizy listu Pico della Mirandoli O języku filozofów, skierowanego do Hermolausa Barbara. W pierwszej części tekstu zaprezentowano kontekst sporu, czyli znamienne dla epoki napięcie między filozofią a retoryką, oraz krytykę filozofii  scholastycznej z perspektywy humanistów. Uwyraźnienie stanowiska Barbara pozwala uchwycić sedno sporu z Pikiem, mianowicie:jakiej prawdy – prawdy o czym – powinniśmy poszukiwać? Do analizy stanowiska Pika posłużyły wypreparowane z jego tekstu opozycje: wnętrze/zewnętrze, prawda/pozór, rozum/zmysły i popędy, filozofia/retoryka-sofistyka, człowiek rozumny/człowiek pospolity. Pozwala to uchwycić myśl Pika jako z założenia paradoksalną: okazuje się, że retoryka zarazem zakrywa istotę rzeczy i ją odkrywa. Jest jednocześnie przeszkodą i nieodzownym narzędziem poznania i wyrażania myśli. Dzieje się tak ze względu na nieuchronną historyczność ludzkiej myśli.
TWO-WAY GLOBAL-LOCAL COUPLED FAILURE MODELING WITH RX-FEM
Authors: GAO ZHENJIA , ADLURU HARI K. , LU WEI-TSEN , HOOS KEVIN H. , IARVE ENDEL V.
Published: October 2022

Fiber-reinforced composites are widely used in aerospace structures because of their high specific strength. However, the failure prediction in these heterogeneous engineered materials presents significant challenges due to the multiscale nature and interaction of the damage modes. The computational cost increases dramatically moving from coupon to element to subcomponent and higher levels of the building block ladder. Fine meshes and high-fidelity numerical models are necessary in order to achieve local accuracy but at the same time make the computations prohibitively expensive. The present work focuses on a practical approach, two-way global-local tight coupling, to allow users to setup the modeling easily and reduce the computational cost. This method can capture the global failure. Penalty connection method is used for tight coupling of the local and global regions. Multiple discrete damage modes are allowed in the local region. Two numerical examples are provided to illustrate that the two-way global-local tight coupling can effectively predict the local damage and the global response.
EFFECT OF CONTROLLED LOCAL MICROSTRUCTURAL MODIFICATION OF GLASS FIBER EPOXY COMPOSITES ON PROGRESSIVE DAMAGE PROPAGATION UNDER TENSILE LOADING
Authors: MANOHARAN NITHINKUMAR , GURURAJA SUHASINI
Published: October 2022

Advanced composite materials are defined by hierarchical, heterogeneous, and anisotropic behavior, resulting in complex, multi-scale progressive damage mechanisms, making failure predictions even under simple loading a challenging task. With the widespread usage of polymer composites for structural applications, holes, notches, and other geometric features are often needed for assembly and other functional requirements necessitating improvements to the local architecture around the holes to alleviate associated stress concentration effects. Multiwalled carbon nanotubes (MW-CNTs) when incorporated with epoxy matrix have shown to increase the open-hole tensile (OHT) strength of unidirectional glass fiber reinforced plastic (UD-GFRP) laminates by altering the inherent damage mechanisms. To assess the incipience of damage in MW-CNT modified UD-GFRP laminates, X-ray microcomputed tomography (CT) of the specimen before and after failure have been carried out in the current work. Future work is ongoing to perform in situ tensile testing assisted with X-ray micro-CT to have a better understanding of damage evolution in the specimens.
FORCE FIELD PARAMETERIZATION AND MOLECULAR DYNAMICS SIMULATION OF EPOXY INTERACTION WITH BORON NITRIDE NANOTUBE SURFACES
Authors: BAMANE SWAPNIL , KANHAIYA KRISHAN , HEINZ HENDRIK , ODEGARD GREGORY
Published: October 2022

Wettability is a key phenomenon in understanding solid-liquid interface behavior in composite materials and is important in the manufacturing of boron nitride nanotube (BNNT)-based composite materials. Wettability is often quantified by calculating the contact angle values of liquid resin droplets on reinforcement surfaces. Determining contact angle values using experimental techniques for nanomaterials like BNNT is challenging and costly. Computational simulations with interface calculation capabilities offer an easier approach to solve this problem. In this study, a molecular dynamics framework is used to determine the contact angle values of various epoxy systems on the BNNT surface. The Interface Force-Field (IFF) was used for this study. Forcefield parameters were developed to describe the interaction of boron (B) atoms, nitrogen (N) atoms, and the pi electrons that dominate the out-of-plane behavior of two-dimensional B-N materials. A single layer BNNT surface was modelled as shown in “Figure 1”. For wetting simulations, the selection of resin system is based on a combination of EPON 862 and EPON 828 monomers with aromatic amine hardeners and aliphatic amine hardeners. The results are dependent on the chemical groups present in the resin system, temperature, and the charges on the atoms in the functional groups. The EPON 828 systems show overall better wettability than EPON 862 systems irrespective of choice of hardener.
MICRO-SCALE PROCESS MODELING AND EVALUATION OF CURING-INDUCED RESIDUAL STRESSES IN FIBER-REINFORCED POLYMERS USING HIGHER-ORDER FE MODELS
Authors: NAGARAJ MANISH H. , MAIARU MARIANNA
Published: October 2022

This manuscript presents the analysis of the curing process of thermoset polymers to predict the cure-induced residual stresses at the micro-scale level. A phenomenological cure kinetics model is used to describe the polymerization process, while an instantaneous linear-elastic constitutive law is used to predict residual stress. The computational model leverages higher-order structural theories derived from the Carrera Unified Formulation. A ten-fiber randomly packed repeating unit cell is virtually cured using the proposed higher-order method. The predicted stress state is shown to agree with reference results based on 3D finite element analysis while achieving a multi-fold reduction in the computational effort.
OPTIMIZATION OF FE CRASHWORTHINESS MODEL FOR SHEET MOLDING COMPOUND (SMC) WITH EXTENDED STRENGTH DISTRIBUTION MODEL AND MACHINE LEARNING
Authors: IQBAL SAKIB , XIAO XINRAN
Published: October 2022

Sheet Molding Compound (SMC) possesses good mechanical properties and manufacturing flexibility. Nevertheless, SMC exhibits large scatter in mechanical properties and large difference in strengths under different stress distribution or loading conditions. As a result, the classical modeling techniques based on the mean tensile strength tend to significantly under-predict the flexural responses in finite element (FE) simulations. Probabilistic simulations with a unimodal tensile strength distribution had limited success in improving the predictions. In this work, the statistical distributions of the elastic modulus, tensile strength and compressive strength were considered with bimodal Weibull strength distributions. An optimization procedure for probabilistic FE models using artificial neural network (ANN)-based machine learning (ML) algorithm has been proposed. This procedure was examined through correlating simulations with experimental results for the 3-pt bending case. A set of optimum parameters was determined and subsequently examined in probabilistic simulations of tension, compression, 3-pt, and 4-pt bending cases. Simulations with this approach yielded low errors for all 4 cases and the results reached the steady-state within 20-30 iterations.
FINITE ELEMENT MODELING FOR COMPRESSION STRENGTH PREDICTION OF HONEYCOMB CORES WITH GEOMETRIC IMPERFECTIONS MEASURED USING X-RAY CT IMAGING
Authors: RIVERA ADRIAN XAVIER , VENKATARAMAN SATCHI , KIM HYONNY , PINEDA EVAN , BERGAN ANDREW
Published: October 2022

Aluminum honeycomb cores are used in composite sandwich panels to achieve high bending rigidity while maintaining low weight. Geometric imperfections arise in the walls of metallic honeycomb cores during manufacturing, which affects their compression and impact response. This paper presents finite element modeling of metallic honeycomb cores with measured geometric imperfections. The honeycomb cores are modeled using shell geometry reconstructions of images of cores obtained using X-ray Computer Tomography. Flatwise compression responses of the cores are computed using finite element analyses of honeycomb cores for different representative volume element (RVE) sizes and boundary conditions. It is found that the compression response of the 10x11 cells RVE models can be predicted by the average of single RVE cell models sampled from the 10x11 cells RVE domain. However, this requires appropriate choice of boundary conditions. The non-periodic nature of the imperfection and the variation in geometric imperfection in the double and single thickness walls of the honeycomb core cells lead to interactive buckling of these walls and mode jumping during the amplification of initial imperfections under compression. These interactions play a significant role in the compression response and, therefore, the RVE size and boundary condition choices made should ensure this interaction are accurately captured.
NUMERICAL AND EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER DURING COMPOSITE FUSED FILAMENT FABRICATION
Authors: AVILA FIDEL BAEZ , GHASEMI ROSE , DEHGHAN-NIRI EHSAN , DRACH BORYS
Published: October 2022

Additive manufacturing of fiber-reinforced composite materials enables production of parts with high specific stiffness and strength. Several manufacturers have released their versions of composite 3D printers with the most popular being Markforged® which relies on fused filament fabrication (FFF) process. This paper focuses on numerical and experimental investigation of heat transfer in composite specimens produced via the FFF manufacturing process. The experimental setup combines the Markforged® Mark Two™ composite 3D printer and the FLIR thermal camera. The camera is used to collect full field temperature history of a cylindrical composite specimen 12.7 𝑚𝑚 × 25.4 𝑚𝑚 (𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 × ℎ𝑒𝑖𝑔ℎ𝑡) manufactured using composite filament Onyx™ consisting of nylon matrix and chopped carbon fibers. The thermal data is used to validate three-dimensional finite element simulations of transient heat transfer during the filament deposition process. Two approaches are used for the numerical simulation: “element-by-element” in which elements are activated in sequence following a realistic deposition path, and “layer-by-layer” in which all elements of a layer are activated simultaneously and then allowed to cool. The latter approach is more computationally efficient. Micromechanical homogenization is used to estimate the effective conductivity values of the fiber-reinforced Onyx™ filament. Full-field temperature distribution and path plots are generated via both numerical approaches and from experimental data. The element-by-element approach appears to be capable of predicting the experimentally observed temperature distribution below the most recently deposited layer.
IN-SITU BENDING PERFORMANCE OF NANOSTRUCTURED CARBON FIBER REINFORCED POLYMER COMPOSITES
Authors: KAYNAN OZGE , FALLAHI HAMED , JARRAHBASHI DORRIN , ASADI AMIR
Published: October 2022

Depositing carbon nanotubes (CNTs) into carbon fiber reinforced polymer composites (CFRPs) is challenging because of the need for complicated lab-scale processes and toxic chemical dispersants that makes conventional means of processing less compatible with existing industrial procedures for large-scale applications. In this work, a scalable supercritical CO2-assisted atomization technique is used to effectively deposit hybrid CNTs in CFRPs allowing them to boost their functionality and tailor the microstructure. Cellulose nanocrystals (CNCs) are utilized to create hybrid nanostructures with CNTs (CNC bonded CNT) that enables stabilization of CNTs in nontoxic media, i.e., water, and this promotes the scalability of the process. According to Zeta potential values, CNCs successfully stabilize CNTs in water suspension. Scanning electron microscopy (SEM) micrographs show hybrid CNC bonded CNTs are homogeneously dispersed on the carbon fiber surface. According to the in-situ bending test under the optical microscope, crack propagation is hindered by engineered hybrid CNT nanostructures in the modified CFRP whereas neat CFRP exhibits low crack growth resistance due to the uninterrupted crack propagation in the continuous epoxy matrix. Our results imply that this strategy probes the importance of new controlled manufacturing of hybrid nanostructures through evaporation‑induced self‑assembly of nanocolloidal droplets, and allows for tailoring of the desired properties of nanostructured composites.
COMPOSITE LAMINATE PROGRESSIVE DAMAGE FAILURE ANALYSIS BENCHMARKING USING HIGH FIDELITY INSPECTION DAMAGE MAPS FOR OPEN HOLE TENSION COUPONS AT TWO ENVIRONMENTAL CONDITIONS
Authors: CARPENTER BRIAN , HENSON LANDON , CUTTING REBECCA , MOLITOR MATTHEW
Published: October 2022

This paper presents an approach for using high fidelity test data to inform modeling methods on progressive damage failure analysis for composite open hole tension specimens at room temperature ambient and cold temperature dry conditions. To do this, the progressive damage failure models will use a publically available continuum damage mechanics based material model (MAT299) to represent lamina level damage in unidirectional composite systems within LS-DYNA. The models will be evaluated against a high fidelity experimental database from a project sponsored by the Office of Naval Research. The database consists of experimental data for the material system IM7/5320-1. Soft, medium, and hard laminates at each environmental condition will be the focus of this paper.