bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between dry skin and pressure injury in older patients: A multicentre cross‐sectional survey in China
Authors: Jiang Qixia , Chen Kesu , Liu Yuxiu , Zhou Jihong , Bai Yuxuan , Zhao Jing , Weng Yajuan , Zhu Yuling , Feng Haixia , Wang Jing , Cai Yunmin , Ou Yulan
Published: October 2022

Dry skin and pressure injuries in older persons have become global health care problems. This was a multicentre, prospective cross‐sectional study in 44 hospitals and 8 long term care institutions from 20 provinces, autonomous regions and municipalities in China and aimed to explore the relationship between the two skin problems in older patients. We mainly found 11 602 cases with dry skin and 1076 cases with pressure injuries in a total of 33 769 valid participants. The overall prevalence of dry skin and pressure injuries was 34.4% (95% confidence interval [CI] 33.9–34.9) and 3.1% (95% CI 2.9–3.3). Stage 2+ pressure injuries were the most (32.9%), followed by stage 1 (32.4%). The patients with dry skin had more pressure injuries than ones without dry skin (50.0% vs 33.9%). The patients with very severe and severe dry skin had more pressure injury risk (OR 2.22 and 1.90) and more stage 2+ pressure injury risk (OR 2.83 and 1.63). Other nine predictors associated with overall pressure injuries and stage 2+ pressure injuries. The area under receiver operating characteristic (ROC) curve of the predictive models of overall pressure injuries and stage 2+ pressure injuries were 0.89 (95% CI 0.88–0.90) and 0.91 (95% CI 0.90–0.92), respectively.
Clustering using unsupervised machine learning to stratify the risk of immune‐related liver injury
Authors: Yamamoto Takafumi , Morooka Hikaru , Ito Takanori , Ishigami Masatoshi , Mizuno Kazuyuki , Yokoyama Shinya , Yamamoto Kenta , Imai Norihiro , Ishizu Yoji , Honda Takashi , Yokota Kenji , Hase Tetsunari , Maeda Osamu , Hashimoto Naozumi , Ando Yuichi , Akiyama Masashi , Kawashima Hiroki
Published: October 2022

Background and Aim

Immune‐related liver injury (liver‐irAE) is a clinical problem with a potentially poor prognosis.

Methods

We retrospectively collected clinical data from patients treated with immune checkpoint inhibitors between September 2014 and December 2021 at the Nagoya University Hospital. Using an unsupervised machine learning method, the Gaussian mixture model, to divide the cohort into clusters based on inflammatory markers, we investigated the cumulative incidence of liver‐irAEs in these clusters.

Results

This study included a total of 702 patients. Among them, 492 (70.1%) patients were male, and the mean age was 66.6 years. During the mean follow‐up period of 423 days, severe liver‐irAEs (Common Terminology Criteria for Adverse Events grade ≥ 3) occurred in 43 patients. Patients were divided into five clusters (a, b, c, d, and e). The cumulative incidence of liver‐irAE was higher in cluster c than in cluster a (hazard ratio [HR]: 13.59, 95% confidence interval [CI]: 1.70–108.76, P = 0.014), and overall survival was worse in clusters c and d than in cluster a (HR: 2.83, 95% CI: 1.77–4.50, P < 0.001; HR: 2.87, 95% CI: 1.47–5.60, P = 0.002, respectively). Clusters c and d were characterized by high temperature, C‐reactive protein, platelets, and low albumin. However, there were differences in the prevalence of neutrophil count, neutrophil‐to‐lymphocyte ratio, and liver metastases between both clusters.

Conclusions

The combined assessment of multiple markers and body temperature may help stratify high‐risk groups for developing liver‐irAE.
Experience of internet‐delivered cognitive behavioural therapy among patients with non‐cardiac chest pain
Authors: Eriksson‐Liebon Magda , Lundgren Johan , Rytterström Patrik , Johansson Peter , Mourad Ghassan
Published: October 2022

Aims and Objective

To explore the experiences of patients with non‐cardiac chest pain and cardiac anxiety regarding participation in an internet‐delivered cognitive behavioural therapy program.

Background

Non‐cardiac chest pain is common and leads to cardiac anxiety. Internet‐delivered cognitive behavioural therapy may be a possible option to decrease cardiac anxiety in these patients. We have recently evaluated the effect of an internet‐delivered cognitive behavioural therapy program on cardiac anxiety.

Design

An inductive qualitative study using content analysis and the COREQ checklist.

Methods

Semi‐structured interviews with 16 Swedish patients, who had participated in the internet‐delivered cognitive behavioural therapy program.

Results

Three categories were found. The first, ‘Driving factors for participation in the internet‐delivered cognitive behavioural therapy program’ described the impact of pain on their lives and struggle that led them to participating in the program. The second, ‘The program as a catalyst’ described that the program was helpful, trustworthy and useful and the last category, ‘Learning to live with chest pain’ described the program as a tool for gaining the strength and skills to live a normal life despite chest pain.

Conclusions

The program was experienced as an opportunity to return to a normal life. The program was perceived as helpful, trustworthy and useful, which helped the participants challenge their fear of chest pain and death, and gain strength and new insights into their ability to live a normal life.

Relevance to Clinical Practice

A tailored internet‐delivered cognitive behavioural therapy program delivered by a nurse therapist with clinical experience of the patient group is important to improve cardiac anxiety.

Patient or Public Contribution

Patients or the general public were not involved in the design, analysis or interpretation of the data of this study, but two patients with experience of non‐cardiac chest pain were involved in the development of the pilot study.

Trial Registration

ClinicalTrials.gov NCT03336112; https://www.clinicaltrials.gov/ct2/show/NCT03336112.
2022 WSAVA guidelines for the recognition, assessment and treatment of pain
Authors: Monteiro B. P. , Lascelles B. D. X. , Murrell J. , Robertson S. , Steagall P. V. M. , Wright B.
Published: October 2022

Animal sentience refers to the capacity of animals to feel both positive and negative emotions including that of pain. As veterinary health professionals, we have a medical and ethical duty to mitigate suffering from pain to the best of our ability. In 2014, the first Global Pain Council World Small Animal Veterinary Association (WSAVA) Guidelines for the Recognition, Assessment and Treatment of Pain was published and remains to this day one of the most relevant and widespread documents of its kind. The 2022 WSAVA Global Pain Management Guidelines evolves from the first document with updated scientific information reflecting major advances in veterinary pain medicine in the last decade. This document is designed to provide the user with easy‐to‐implement, core fundamentals on the successful recognition and treatment of pain in the day‐to‐day small animal clinical practice setting. It provides basic and practical information with an extensive reference list to guide those who want to further their knowledge on pain management. The 2022 WSAVA Global Pain Management Guidelines should be easily implemented regardless of practice setting and/or location for the promotion and advance of pain management and animal welfare.
Gradient diffusion strips for detecting azole resistance in Aspergillus fumigatus sensu lato
Authors: Serrano‐Lobo Julia , Gómez Ana , Reigadas Elena , Muñoz Patricia , Escribano Pilar , Guinea Jesús ,   the ASPEIN Study Group
Published: October 2022

Background

Studies comparing gradient diffusion strips (GDSs) and the EUCAST E.Def 9.4 microdilution method are scarce, thwarted by a low number of isolates, and restricted to selected antifungal agents.

Objectives

We evaluated the performance of GDSs to detect azole resistance in A. fumigatus, including cryptic species.

Patients/Methods

A. fumigatus sensu stricto (n = 89) and cryptic species (n = 52) were classified as susceptible or resistant to itraconazole, voriconazole, posaconazole and isavuconazole (EUCAST E.Def 9.4; clinical breakpoints v10). A. fumigatus sensu stricto azole‐resistant isolates had the following cyp51A gene mutations: TR34‐L98H (n = 24), G54R (n = 5), TR46‐Y121F‐T289A (n = 1), F46Y‐M172V‐N248T‐D255E‐E427K (n = 1), F165L (n = 1) and cyp51A gene wild type (n = 3). GDSs (ETEST®, bioMèrieux, Marcy‐l'Etoile, France and Liofilchem®, Roseto degli Abruzzi, Italy) MICs were obtained by following the manufacturer's guidelines.

Results

For A. fumigatus sensu stricto, itraconazole MICs >1.5 mg/L, voriconazole >0.38 mg/L, posaconazole >0.75 mg/L, and isavuconazole >0.5 mg/L correctly separated resistant from susceptible isolates with two exceptions. Considering the aforementioned cut‐off MICs, sensitivity/specificity values of GDSs to detect azole resistance were: itraconazole (97%/100%), voriconazole (97%/100%), posaconazole (97%/100%) and isavuconazole (93.3%/100%). For cryptic species isolates, voriconazole MICs >1 mg/L and isavuconazole >0.75 mg/L separated resistant isolates from susceptible isolates with 15 and 27 exceptions, respectively. Considering the aforementioned cut‐off MICs, sensitivity/specificity values were as follows: voriconazole (68.1%/100%) and isavuconazole (25%/100%). For itraconazole and posaconazole, it was not possible to establish cut‐off values.

Conclusions

We set tentative cut‐off MIC values to correctly spot resistant Aspergillus fumigatus sensu stricto isolates using GDSs. The performance against cryptic species was poor.
Introduction. Anarchism and the national question—historical, theoretical and contemporary perspectives
Authors: Gutiérrez José A , Kinna Ruth
Published: October 2022

This article provides an introduction to the themed section ‘Anarchism and the national question—historical, theoretical and contemporary perspectives.’ We discuss first the long and often overlooked engagement of anarchists with the colonial and national liberation question, particularly—but not exclusively—in the heyday of the movement (from the second half of the 19th to the first decades of the 20th century). We discuss in particular the overlaps and tensions between anarchists and republicans (those who favoured republics as opposed to monarchies) and anti‐colonial nationalists (anti‐colonialists who defended the right of national self‐determination). Then we proceed to discuss the potential for a dialogue between anarchist and nationalism studies based on three interventions. First, to problematise the narrative that conflates nations with state‐building processes. Second, to better grasp the emergence of alternatives to the nation–state as a historical construct. Third, to complicate narratives that associate in an unproblematic fashion internationalism and classless society. Finally, the introduction highlights the four questions which lie at the core of the themed section and discuss briefly how the papers relate to these.
Integrated phylogenomic analyses unveil reticulate evolution inParthenocissus(Vitaceae), highlighting speciation dynamics in theHimalayan–HengduanMountains
Authors: Yu Jinren , Niu Yanting , You Yichen , Cox Cymon J. , Barrett Russell L. , Trias‐Blasi Anna , Guo Jing , Wen Jun , Lu Limin , Chen Zhiduan
Published: October 2022

Hybridization caused by frequent environmental changes can lead both to species diversification (speciation) and to speciation reversal (despeciation), but the latter has rarely been demonstrated.Parthenocissus, a genus with its trifoliolate lineage in the Himalayan–Hengduan Mountains (HHM) region showing perplexing phylogenetic relationships, provides an opportunity for investigating speciation dynamics based on integrated evidence.

We investigated phylogenetic discordance and reticulate evolution inParthenocissusbased on rigorous analyses of plastome and transcriptome data. We focused on reticulations in the trifoliolate lineage in the HHM region using a population‐level genome resequencing dataset, incorporating evidence from morphology, distribution, and elevation.

Comprehensive analyses confirmed multiple introgressions withinParthenocissusin a robust temporal–spatial framework. Around the HHM region, at least three hybridization hot spots were identified, one of which showed evidence of ongoing speciation reversal.

We present a solid case study using an integrative methodological approach to investigate reticulate evolutionary history and its underlying mechanisms in plants. It demonstrates an example of speciation reversal through frequent hybridizations in the HHM region, which provides new perspectives on speciation dynamics in mountainous areas with strong topographic and environmental heterogeneity.
Assessment of the occlusal outcomes in patients treated with orthognathic surgery and clear aligners
Authors: Kwon Taewoo , Alshehri Abdulrahman , Palo Ledjo , Kuo Chia‐Ling , Mu Jinjian , Blanck Nyle , Nanda Ravindra , Arqub Sarah Abu , Uribe Flavio
Published: October 2022

Objective

This retrospective two‐centre study aimed to evaluate the occlusal outcomes in patients undergoing orthognathic surgery with clear aligners.

Methods

A retrospective chart review and occlusal outcomes for 15 patients (10 females and five males) with different types of dentofacial deformities in the anteroposterior, vertical and transverse dimensions, who underwent orthognathic surgery in conjunction with clear aligners were evaluated. Weighed Peer Assessment Rating (PAR) index scores of the pre‐treatment and post‐treatment digital models were used to assess initial complexity, final occlusal outcomes and degree of improvement with surgery and clear aligners.

Results

The mean post‐treatment PAR score was 3.5 ± 2.54, which was a statistically significant improvement from the pre‐treatment PAR score of 27.63 ± 12.09, an 87% improvement was achieved. All subcategories of the PAR index showed statistically significant improvement except for midline assessment component.

Conclusions

Occlusal outcomes with aligners showed great improvement as indicated with the PAR index scores. Orthognathic surgical cases can be treated efficiently with aligners and future studies should compare occlusal outcomes between orthognathic surgical patients treated with clear aligners and those treated with fixed appliances.
Characterization of Leuconostoc mesenteroides MJM60376 as an oral probiotic and its antibiofilm activity
Authors: Gu Mingkun , Nguyen Huong Thi , Cho Joo‐Hyung , Suh Joo‐Won , Cheng Jinhua
Published: October 2022

Lactic acid bacteria have been widely used as probiotics for improving gut health. However, studies on oral probiotics were very limited. In this study, 67 lactic acid bacteria (LAB) were isolated from fermented food and screened for antagonistic activity against Streptococcus mutans, the causative pathogen of dental caries. Leuconostoc mesenteroides MJM60376 showed the highest antagonistic activity against S. mutans KCTC3065. L. mesenteroides MJM60376 also showed oral probiotic characteristics including weak acid production, lysozyme tolerance, adhesion to oral epithelial cell (YD‐38), antibiotic susceptibility, and good coaggregation ability with S. mutans. Furthermore, the biofilm formation of S. mutans was significantly reduced when cocultured with L. mesenteroides. Scanning electron microscopy analysis showed that amounts of attached bacteria of S. mutans and network‐like structures were significantly reduced by L. mesenteroides MJM60376. Cell‐free supernatant (CFS) of L. mesenteroides MJM60376 also greatly inhibited biofilm formation of S. mutans from the adherent stage, the activity remained even after it was treated with catalase, trypsin, or pH neutralized. Expression levels of biofilm formation‐related genes were significantly reduced in S. mutans when it was treated with the CFS of L. mesenteroides MJM60376. Therefore, L. mesenteroides MJM60376 has great potential to be used as a multifunctional ingredient.
Pharmacological Effects of Resveratrol in Intervertebral Disc Degeneration: A Literature Review
Authors: Liu Ming‐yang , Zhang Liang , Zang Wei‐dong , Zhang Kai‐guang , Li Hai‐jun , Gao Yan‐zheng
Published: October 2022

Intervertebral disc degeneration (IDD) is a high incidence disease of musculoskeletal system that often leads to stenosis, instability, pain and even deformity of the spinal segments. IDD is an important cause of discogenic lower back pain and often leads to large economic burden to families and society. Currently, the treatment of IDD is aimed at alleviating symptoms rather than blocking or reversing pathological progression of the damaged intervertebral disc.Resveratrol (RSV) is a polyphenol phytoalexin first extracted from theVeratrum grandiflflorum O. Loesand can be found in various plants and red wine. Owing to the in‐depth study of pharmacological mechanisms, the therapeutic potential of RSV in various diseases such as osteoarthritis, neurodegenerative diseases, cardiovascular diseases and diabetes have attracted the attention of many researchers. RSV has anti‐apoptotic, anti‐senescent, anti‐inflammatory, anti‐oxidative, and anabolic activities, which can prevent further degeneration of intervertebral disc cells and enhance their regeneration. With high safety and various biological functions, RSV might be a promising candidate for the treatment of IDD. This review summarizes the biological functions of RSV in the treatment of IDD and to facilitate further research.
Periconceptional antibiotic use and spontaneous abortion: A prospective cohort study
Authors: Crowe Holly Michelle , Hatch Elizabeth Elliott , Wang Tanran R. , Horsburgh Charles Robert , Mikkelsen Ellen Margrethe , Kuohung Wendy , Wise Lauren Anne , Wesselink Amelia Kent
Published: October 2022

Background

Many reproductive‐aged North Americans use antibiotics in the weeks preceding conception or during early pregnancy. Antibiotic use may influence risk of spontaneous abortion (SAB) by disrupting the reproductive tract microbiome or treating harmful infections. However, this association has not been extensively studied.

Objective

To determine the extent to which periconceptional antibiotic use is associated with the risk of SAB.

Methods

We analysed data from an internet‐based preconception cohort study of pregnancy planners. Eligible participants self‐identified as female, were aged 21–45 years, resided in the USA or Canada, and conceived during 12 months of follow‐up (n = 7890). Participants completed an enrolment questionnaire during June 2013–September 2021 and bimonthly follow‐up questionnaires for up to 12 months or until a reported pregnancy, whichever came first. Pregnant participants completed questionnaires in early (~8–9 weeks) and late (~32 weeks) gestation. We assessed antibiotic use, including type (penicillins, nitrofurantoin, cephalosporins and macrolides) and indication for use, during the previous 4 weeks on preconception questionnaires. Participants reported pregnancies and SAB on follow‐up and pregnancy questionnaires. We used Cox proportional hazards regression models with gestational weeks as the time scale to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between periconceptional antibiotic use and SAB, controlling for potential demographic, medical, and lifestyle confounders.

Results

Nineteen percent (n = 1537) of pregnancies ended in SAB. Participants reported periconceptional antibiotic use in 8% of pregnancies ending in SAB and 7% not ending in SAB. Periconceptional antibiotic use was not appreciably associated with SAB (adjusted HR 1.06, 95% CI 0.88, 1.28). We observed no strong associations between antibiotic type, indication for use, or recency of exposure and SAB risk.

Conclusions

Periconceptional antibiotic use was not appreciably associated with SAB in this study. This association is likely complicated by antibiotic type and dosage, timing of conception, and the individual's overall health.
How can procurement create (sustainable) public value under the Bipartisan Infrastructure Deal?
Authors: Patrucco Andrea S. , Dimand Ana‐Maria , Neshkova Milena I. , Cevallos Madison M.
Published: October 2022

The economic response of the US government to the COVID‐19 pandemic envisions massive investment in infrastructure construction. Yet, governments contract out public works and might lack the capacity to meet the increased demand for new construction. Drawing on a mix of survey and interview data, we identify critical deficiencies in contract capacity that might lead to a loss of public resources and further erode trust in the government. We propose a plan for restructuring public procurement systems and offer solutions around four foci: collaboration, training, flexibility, and sustainability. This transformation path would enhance government contract capacity and use markets to signal a demand for sustainable infrastructure and create public value in line with the strategic objectives of the Bipartisan Infrastructure Deal.
To join or not to join? Insights from coopetitive RD&I projects
Authors: Smiljic Sanja , Aas Tor Helge , Mention Anne‐Laure
Published: October 2022

Multipartner research, development and innovation (RD&I) projects are increasingly used to achieve complex innovation goals and keep pace with today's technological imperatives. The involvement of both competing and noncompeting partners increases the complexity of the relationships and poses a challenge to the outcomes of such projects. Therefore, the right choice of partners is particularly important in this context. Although previous research has mainly examined how focal firms deliberately select collaborative partners, this study demonstrates how non‐focal firms evaluate invitations to participate in RD&I projects with multiple partners and direct competitors. Going beyond the coopetitive dyad, we qualitatively examine six multipartner RD&I projects in mature industries involving competitors and noncompetitors. The findings suggest that the evaluation process differs between exploration and exploitation projects. We identify critical factors that guide direct competitors' process of deciding whether to participate in both types of projects, and we provide new insights into the attractiveness of coopetitive RD&I collaborations for firms in mature industries. The study's propositions advance theory and can be tested in future empirical studies. This study also provides valuable guidance for practitioners considering embarking on a coopetitive journey.
86 novel HLA‐E alleles discovered through full‐gene sequencing of 6227 hematopoietic cell transplant patients and unrelated donors
Authors: Lucas Jonathan A. M. , Georgiou Xenia , Cooper Michael A. , Robinson James , Marsh Steven G. E. , Mayor Neema P.
Published: October 2022

Until recently the number of alleles of the nonclassical HLA class I gene HLA‐E documented in the IPD‐IMGT/HLA Database was small and as a result, the gene was often not considered to be notably polymorphic. Here, we describe our work in identifying and submitting 86 novel HLA‐E alleles after full‐gene single‐molecule real‐time (SMRT) DNA sequencing of 6227 DNA samples. These samples were comprised of 2468 patients undergoing hematopoietic cell transplantation and 3759 unrelated potential donors. A total of 111 unique HLA‐E alleles were detected in this cohort. The majority of novel alleles (79.1%) contained polymorphisms in intronic regions, highlighting the significant undiscovered variation present in the noncoding regions of the HLA‐E gene.
The chromosome‐level genome of Akebia trifoliata as an important resource to study plant evolution and environmental adaptation in the Cretaceous
Authors: Zhong Shengfu , Li Bin , Chen Wei , Wang Lili , Guan Ju , Wang Qiang , Yang Zujun , Yang Hao , Wang Xianshu , Yu Xiaojiao , Fu Peng , Liu Hongchang , Chen Chen , Tan Feiquan , Ren Tianheng , Shen Jinliang , Luo Peigao
Published: October 2022

The environmental adaptation of eudicots is the most reasonable explanation for why they compose the largest clade of modern plants (>70% of angiosperms), which indicates that the basal eudicots would be valuable and helpful to study their survival and ability to thrive throughout evolutionary processes. Here, we detected two whole‐genome duplication (WGD) events in the high‐quality assembled Akebia trifoliata genome (652.73 Mb) with 24 138 protein‐coding genes based on the evidence of intragenomic and intergenomic collinearity, synonymous substitution rate (KS) values and polyploidization and diploidization traces; these events putatively occurred at 85.15 and 146.43 million years ago (Mya). The integrated analysis of 16 species consisting of eight basal and eight core eudicots further revealed that there was a putative ancient WGD at the early stage of eudicots (temporarily designated θ) at 142.72 Mya, similar to the older WGD of Akebia trifoliata, and a putative core eudicot‐specific WGD (temporarily designated ω). Functional enrichment analysis of retained duplicate genes following the θ event is suggestive of adaptation to the extreme environment change in both the carbon dioxide concentration and desiccation around the Jurassic–Cretaceous boundary, while the retained duplicate genes following the ω event is suggestive of adaptation to the extreme droughts, possibly leading to the rapid spread of eudicots in the mid‐Cretaceous. Collectively, the A. trifoliata genome experienced two WGD events, and the older event may have occurred at the early stage of eudicots, which likely increased plant environmental adaptability and helped them survive in ancient extreme environments.
Markers of inflammation in free‐living African elephants (Loxodonta africana): Reference intervals and diagnostic performance of acute phase reactants
Authors: Steyrer Christine , Miller Michele , Hewlett Jennie , Buss Peter , Hooijberg Emma H.
Published: October 2022

Introduction

Acute phase reactants (APRs) have not been investigated in free‐living African elephants (Loxodonta africana), and there is little information about negative APRs albumin and serum iron in elephants.

Objectives

We aimed to generate reference intervals (RIs) for APRs for free‐living African elephants, and to determine the diagnostic performance of APRs in apparently healthy elephants and elephants with inflammatory lesions.

Methods

Stored serum samples from 49 apparently healthy and 16 injured free‐living elephants were used. The following APRs and methods were included: albumin, bromocresol green; haptoglobin, colorimetric assay; serum amyloid A (SAA), multispecies immunoturbidometric assay, and serum iron with ferrozine method. Reference intervals were generated using the nonparametric method. Indices of diagnostic accuracy were determined by receiver‐operator characteristic (ROC) curve analysis.

Results

Reference intervals were: albumin 41–55 g/L, haptoglobin 0.16–3.51 g/L, SAA < 10 mg/L, and serum iron 8.60–16.99 μmol/L. Serum iron and albumin concentrations were lower and haptoglobin and SAA concentrations were higher in the injured group. Serum iron had the best ability to predict health or inflammation, followed by haptoglobin, SAA, and albumin, with the area under the ROC curve ranging from 0.88–0.93.

Conclusions

SAA concentrations were lower in healthy African vs Asian elephants, and species‐specific RIs should be used. Serum iron was determined to be a diagnostically useful negative APR which should be added to APR panels for elephants.
Antiwindup Compensator-Based Control for Periodic Piecewise Delayed Systems With Input Saturations
Authors: Satheesh T. , Sakthivel R. , Harshavarthini S. , Manikandan R. , Almakhles D. J.
Published: October 2022

This work examines the stabilization problem for periodic piecewise systems (PPSs) with state and input delays, actuator saturations, and external disturbances via an antiwindup compensator (AWC)-based dynamic controller. Specifically, the undesirable consequences caused by saturation are alleviated by implementing the AWC-based dynamic controller. More precisely, AWC not only eliminates the saturation effects but also enlarges the estimation of the domain of attraction. Moreover, by constructing a suitable Lyapunov–Krasovskii functional, the sufficient conditions affirming asymptotic stability of addressed PPSs are established in the form of linear matrix inequalities (LMIs). Notably, the developed LMI conditions can be effectively solved using standard numerical packages and the desired antiwindup gain matrices can be calculated with satisfactory disturbance attenuation level. Finally, two numerical examples are given to demonstrate the usefulness and efficiency of the developed theoretical findings.
Effects of Upstream Wakes on the Boundary Layer Over a Low-Pressure Turbine Blade
Authors: De Vincentiis Luca , Ðurović Kristina , Lengani Davide , Simoni Daniele , Pralits Jan , Henningson Dan S. , Hanifi Ardeshir
Published: October 2022

In the present work, the evolution of the boundary layer over a low-pressure turbine blade is studied using direct numerical simulations, with the aim of investigating the unsteady flow field induced by the rotor-stator interaction. The freestream flow is characterized by the high level of freestream turbulence and periodically impinging wakes. As in the experiments, the wakes are shed by moving bars modeling the rotor blades and placed upstream of the turbine blades. To include the presence of the wake without employing an ad-hoc model, we simulate both the moving bars and the stationary blades in their respective frames of reference and the coupling of the two domains is done through appropriate boundary conditions. The presence of the wake mainly affects the development of the boundary layer on the suction side of the blade. In particular, the flow separation in the rear part of the blade is suppressed. Moreover, the presence of the wake introduces alternating regions in the streamwise direction of high- and low-velocity fluctuations inside the boundary layer. These fluctuations are responsible for significant variations of the shear stress. The analysis of the velocity fields allows the characterization of the streaky structures forced in the boundary layer by turbulence carried by upstream wakes. The breakdown events are observed once positive streamwise velocity fluctuations reach the end of the blade. Both the fluctuations induced by the migration of the wake in the blade passage and the presence of the streaks contribute to high values of the disturbance velocity inside the boundary layer with respect to a steady inflow case. The amplification of the boundary layer disturbances associated with different spanwise wavenumbers has been computed. It was found that the migration of the wake in the blade passage stands for the most part of the perturbations with zero spanwise wavenumber. The non-zero wavenumbers are found to be amplified in the rear part of the blade at the boundary between the low- and high-speed regions associated with the wakes.
Interdependency of Core Temperature and Glabrous Skin Blood Flow in Human Thermoregulation Function: A Pilot Study
Authors: Namisnak Laura H. , Khoshnevis Sepideh , Diller Kenneth R.
Published: October 2022

Human thermoregulation is governed by a complex, nonlinear feedback control system. The system consists of thermoreceptors, a controller, and effector mechanisms for heat exchange that coordinate to maintain a central core temperature. A principal route for heat flow between the core and the environment is via convective circulation of blood to arteriovenous anastomoses located in glabrous skin of the hands and feet. This paper presents new human experimental data for thermoregulatory control behavior along with a coupled, detailed control system model specific to the interdependent actions of core temperature and glabrous skin blood flow (GSBF) under defined transient environmental thermal stress. The model was tuned by a nonlinear least-squared curve fitting algorithm to optimally fit the experimental data. Transient GSBF in the model is influenced by core temperature, nonglabrous skin temperature, and the application of selective thermal stimulation. The core temperature in the model is influenced by integrated heat transfer across the nonglabrous body surface and GSBF. Thus, there is a strong cross-coupling between GSBF and core temperature in thermoregulatory function. Both variables include a projection term in the model based on the average rates of their change. Six subjects each completed two thermal protocols to generate data to which the common model was fit. The model coefficients were unique to each of the twelve data sets but produced an excellent agreement between the model and experimental data for the individual trials. The strong match between the model and data confirms the mathematical structure of the control algorithm.
Experimental and Simulations Study of Thermal Performance of Cell-to-Pack Structure for a Lithium-Ion Battery Pack
Authors: Shen Kai , Yang Linsen , Sun Jieyu , Xu Chengshan , Wang Huaibin , Zheng Yuejiu , Feng Xuning
Published: October 2022

A new model for simulating battery temperature changes from the lower surface to the upper surface is proposed. The cell model is established with experimental calibration. Simultaneously, the cell-to-pack (CTP) model is established through experimental benchmarking. In addition, the thermal properties of CTP and an ordinary battery pack that has an enclosure on the basis were compared under four different working conditions. The results indicate that adding an enclosure to the CTP has little effect on the thermal performance of the battery pack. Adding an enclosure to the CTP hardly improves the temperature uniformity of the battery under cooling conditions; the temperature difference between the upper and lower surfaces of the batteries at both ends of the module drops by approximately 0.5 °C, while the central temperature difference is basically unchanged. Compared with fast charging without cooling, the battery temperature dropped by more than 12 °C under the fast charge condition with cooling. More importantly, the specific energy and packaging efficiency of the battery dropped from 160.27 Wh/kg and 73.1% to 148.72 Wh/kg and 67.8%, respectively, after the CTP was added with an enclosure.
Micro-mixing Combustion for Highly Recuperated Gas Turbines: Effects of Inlet Temperature and Fuel Composition on Combustion Stability and NOx Emissions
Authors: Landry-Blais A. , Sivić S. , Picard M.
Published: October 2022

The micro-mixing combustion concept offers an elegant compromise between premixed and non-premixed combustion. By mixing the fuel and air at the smallest scale possible, one can achieve NOx emissions comparable to premixed combustion while minimizing the risks of autoignition and flashback, making this approach particularly well suited to high inlet temperature applications such as sub-MW recuperated gas turbines used in aerospace applications. This paper seeks to bridge the gap between current micro-mixing literature, limited to inlet temperatures < 800 K and hydrogen or hydrogen-rich fuels, with the design requirements of highly recuperated gas turbines, which operate on hydrocarbons at inlet temperatures > 950 K.

Micro-mixing fuel nozzles are additively manufactured in Inconel 625, having up to hundreds of fuel injection holes as small as 250 μm. In addition to hydrogen, these nozzles are tested with hydrocarbon-based fuels such as propane, natural gas, and Jet A-1. An axial swirler is used to induce recirculation of the products behind the nozzle, which helps stabilize combustion with hydrocarbons due to their longer reaction times and slower flame speeds. Experimental results show that NOx emissions can be decreased down to premixed levels if the jet Damköhler number is kept under a critical value, which requires increasingly smaller holes or higher jet velocities as the inlet temperature increases. Combustion instabilities are observed at low inlet temperatures with hydrocarbons, which are also correlated to the jet Damköhler number. There is a window in which both low NOx and stable combustion is possible, which resulted in corrected NOx emissions of < 10 ppm for all the fuels tested at highly recuperated gas turbines conditions, specifically combustor inlet temperature of 950 K and flame temperature of 1550 K. The high inlet temperature also allowed to fully vaporize liquid fuels within the injector, leading to potential reductions in smoke emissions due to the absence of fuel droplets in the combustion zone.
Unsteady Flow Simulations of an Axial Compressor Cascade Subjected to Free Stream Wakes
Authors: Duda Benjamin , Laskowski Gregory M.
Published: October 2022

The flow through a 2.5D axial compressor cascade blade-row is simulated using a compressible Lattice-Boltzmann Method. The simulations are carried out for a nominal flow condition that yields a Reynolds number of 300,000 based on the axial chord and an inlet Mach number of 0.66. The simulations incorporate incoming wakes generated by moving bars with an equivalent reduced frequency of 1.9.

A URANS simulation is carried out first, which reveals deficiencies in predicting time-averaged isentropic surface Mach numbers and wall shear stresses when compared against published DNS results. In order to increase the accuracy of the simulation, an implicit LES is run on a wall-resolved mesh. These results match the reference data because transition effects are correctly accounted for. A new, transition enabled hybrid RANS-LES approach is then carried out which shows that similar accuracy as the wall resolved LES can be obtained.
An Efficient Unsteady 1-Way Coupling Method of Combustor and Turbine
Authors: Gründler Jonathan , Schiffer Heinz-Peter , Lehmann Knut
Published: October 2022

In order to improve the aerothermal predictions of high pressure turbine Computational Fluid Dynamics (CFD) simulations, this paper presents a novel method to prescribe unsteady boundary conditions to transient, scale resolving simulations. The method is based on the compression of the interface data at the Combustor Turbine Interface (CTI), by using Proper Orthogonal Decomposition and Fourier Series (PODFS). The interface data can eater be collected from a combustor simulation or artificially created from mean values, using a digital filter method. The stored interface data size can be greatly reduced in the process. Besides the description of the method, this paper presents a set of Large Eddy Simulation (LES) of a generic test case, to demonstrate the capability of the PODFS method, to produce realistic inlet boundary condition. Furthermore, the method is applied to a set of combustor simulation outlet data, to create a reduced order model of the temporally and spatially resolved interface data. With this application to realistic CTI data, the efficiency of the compression method can be demonstrated and the applicability to turbine simulations can be shown.
Impact of Aerodynamic Asymmetry on the Embedded Rotor Forcing and Mistuned Blade Response
Authors: Hegde Shreyas , Zori Laith , Campregher Rubens , Kielb Robert
Published: October 2022

This paper continues previous research by the current authors in a series of papers describing the impact of multi-row interaction on the forced response behavior of embedded compressor rotors. Specifically, this work dives into an aspect of the embedded rotor forcing that has been sparsely addressed in literature — the impact of an asymmetry in the upstream stator on the forcing function and blade vibration. Although the concept of introducing an asymmetry was introduced nearly 50 years ago, no papers in literature talk about the impact of multi-row interaction with an upstream asymmetric stator in place. All of the current authors’ previous work has discussed the impact of symmetric stators exciting a rotor upstream and downstream. This impact has been quantified at multiple torsional mode crossing some of which result in one-half of the asymmetric stator exciting the rotor and a crossing which results in the downstream stator exciting the rotor. Due to the inability of model reduction methods to model this phenomenon, full wheel computational domains were utilized for all simulations. A commercial code CFX was used for all simulations. In all of the multi-row cases investigated, only a single row excites the rotor. The additional downstream row serves as a reflecting wall that reflects physical waves, which leads to interference.

The second section of this paper describes the details of the in-house mistuning code utilized to predict the blade responses of the individual rotor blades in the system. One of the inputs to this code is the modal force obtained using unsteady CFD in the paper’s first section. The in-house code is based on the FMM, which couples both aero and structural dynamics to predict the blade responses. The key conclusions from this study were: 1) An asymmetry in the upstream stator results in a significant reduction in the forcing function at the crossing frequency. However, the magnitude of forcing could remain significant with a shift to a ‘sideband’ frequency. 2) Introducing an asymmetry is beneficial only when the asymmetric stator excites the rotor and not when any of the other rows excites the rotor. 3) The impact of physical wave reflections was constructive at all torsional mode crossings in line with the earlier conclusions. 4) The mistuned response was well predicted by the FMM at all crossings despite the presence of significant blade disk interaction at these crossings.
The Importance of Shape in Particle Rebound Behaviors
Authors: Wilson Jacob , Qiao Rui , Kappes Matthew , Loebig James , Clarkson Rory
Published: October 2022

Physics-based particle rebound models are essential for the accurate tracking of particles in aero engines. Current models are often informed by analysis of spherical particle impact, but particles ingested in engines typically feature edges and corners. Understanding the effects of particle shape on rebound behavior is critical for ascertaining the range of validity of existing models and for developing improved models. Here, we report on first-principle simulations of cubical particles impacting Ti-6Al-4V targets. Our simulations reveal that, in the case of normal impact at a given incident speed, the coefficient of restitution (CoR) of cubes exhibits significant scattering. The scattering and median of computed CoR show good agreement with recent experiments using sand particles of the same volume-based size, sphericity, and incident speed. Comparison with spheres impacting the same target shows that the median CoR of cubes is significantly lower than that of spheres. Further, the rebound of cubes features significant rotation and transverse velocity, which can account for ∼60% of a rebounding cube’s energy but are negligible modes of energy transfer in impacts involving spheres. We identify that the moment arm length, a parameter that characterizes the mass distribution of angular particles impacting a target, plays a key role in particle rebound, and its distribution is strongly correlated with rebound stochasticity. These findings can benefit the development of physics-based low-order models of angular particle rebound.
Development of a Dynamic Turbine Expansion Model Using a Paired Thermofluid and FEA Methodology
Authors: Ross Michael , Fuls Wim
Published: October 2022

With increased pressure for conventional coal-fired power plants to adopt a flexible operating principle, an increased need for computationally inexpensive thermal and structural turbine models has been observed. This paper documents the formulation of a paired thermofluid and FEA turbine modelling methodology to predict the radial and axial clearances within a 600MW candidate steam turbine during a full cold start procedure. This study formulates a method for sizing and modelling a representative turbine with limited OEM input through the implementation of the Nozzle Analogy theory for axial, multistage steam turbines. Following the development of a full turbine process model and representative 3D FEA turbine model, a successful validation of key turbine temperatures and differential expansions was carried out using real-world plant data within a high level of accuracy. The modelling methodology presented a computationally inexpensive method to predict internal turbine temperature boundaries as well as the structural behaviour of turbine components under transient loads, and proved invaluable in a thorough understanding of flexible turbine operation.
Lean Stability Limits and Exhaust Emissions of Ammonia-Methane-Air Swirl Flames at Micro Gas Turbine Relevant Pressure
Authors: Avila Cristian , Wang Guoqing , Zhu Xuren , Es-Sebbar Et-Touhami , Abdullah Marwan , Younes Mourad , Jamal Aqil , Guiberti Thibault , Roberts William L.
Published: October 2022

This study reports on the lean stability limits and exhaust emissions of ammonia-methane-air swirl flames with varied ammonia fuel fractions. A reduced-scale burner was manufactured, inspired by Ansaldo’s micro gas turbine AE-T100 burner, and it was installed inside a high-pressure combustion duct to operate at 4.5 bar. This pressure corresponds to that found at full-load in the actual micro gas turbine’s combustion chamber. The lean stability limits were measured by igniting the flame at an equivalence ratio of ϕ = 0.85 and then progressively decreasing the equivalence ratio until lean blowout. Emissions of CO2, NO, and N2O were recorded for different equivalence ratios and ammonia fractions. Rich flames at an equivalence ratio of ϕ = 1.20 were also considered. Results show that the equivalence ratio at lean blowout increases when the ammonia fraction increases and that all the ammonia fractions tested lead to flames more prone to lean blowout than the pure methane reference flame. The CO2 emissions are monotonically reduced by increasing the ammonia fraction, both for lean and rich flames. The NO emissions exceed many regulations limit regardless of the ammonia fraction for all lean equivalence ratios. N2O emissions are almost negligible, except for very lean equivalence ratios where the N2O mole fraction in the exhaust reaches unacceptably high values. Only rich ammonia-methane-air flames show good NO and N2O performance. Therefore, FTIR analysis was carried out to quantify the amount of the unburnt NH3 in the exhaust for these flames. Results show that unburnt NH3 concentration is invariant, around 200 ppmv, between 0.70 ≤ XNH3 ≤ 0.95. Data reported in this study provide insights for future work on combustors and after-treatment systems towards zero-emissions micro gas turbines.
Design of a Blowing Type Flow Treatment to Complement Casing Treatments for Compact High-Pressure Compressor Rear Stages
Authors: Köhler Christian P. , Kendall-Torry Christofer , Helcig Christian , Gümmer Volker
Published: October 2022

A common way to increase the operating range of rotor tip limited compressor configurations is the application of casing treatments (CT). However, the resulting strengthening of the rotor tip flow is accompanied by a radial re-balancing effect in the compressor’s flow path. This effect weakens the hub regions downstream of the CT. Consequently, a premature compressor stall can occur near the compressor hub. This paper presents the numerical design efforts for a hub strengthening flow treatment to leverage the potential of CTs within a compact high-pressure compressor (HPC) rear stage concept. A baseline HPC stage with large rotor tip clearances and stage loading is used as a starting point. An increase in compressor operating range substantiates within the rotor tip critical baseline HPC as axial slot CTs are applied. However, a premature stall initiation at the downstream stator hub occurs due to the radial re-balancing effect caused by the CT. Hence, a blowing-type flow treatment (FT) is introduced to delay the formation of the hub corner stall. Different geometrical variations of this FT type are tested numerically via a design of experiments (DoE). Finally, URANS simulations utilize this FT together with CTs to assess the changes in compressor operating behavior. The simulations show an enhancement of the stator operability due to a delay of the onset of the hub corner stall. By applying additional FTs, the adverse effects of the CT on the downstream stator can be partially compensated, and the potential of the HPC design can be leveraged.