bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral surgery waiting lists at an Australian university dental school
Authors: Arora Sitanshu , Ngu Anthony C. S. , Reher Peter
Published: September 2022

Objective

The aim of this study was to investigate the waiting times experienced by patients referred to an Australian University oral surgery clinic over a 2‐year period.

Materials and method

A single‐centre retrospective study was conducted to determine the waiting times for oral surgery services at the Griffith University postgraduate clinic. The first 233 patients were selected out of a total of 587 randomised patients and data collected regarding referral sources, procedures undertaken and the number of days from referral to consultation, then to treatment collected from the clinic's management software.

Results

Of the 233 referrals, 121 were female (52%) and 112 male (48%). Many patients were between 20 and 29 years representing approximately 40% (n = 93) of the sample. Analyses of referred patients showed that a significant number of public (i.e. non‐private‐paying) patients (73%, n = 170) were treated in the study period. Most patients waited only 1–2 weeks to be seen for a consultation from date of referral and treatment from date of consultation. Nearly half (49.7%, n = 116) were treated within 2 months of being referred. Once the patient was referred, the overall mean waiting time was 44 days from referral to treatment. Treatment comprised of either procedures undertaken under local anaesthesia (LA) (76.7%, n = 179) or consultations only with patients either declining treatment, deemed not in need of surgical intervention, or referred for more advanced management such as the need for general anaesthesia (23.3%, n = 54). Surgical removal of third molars (36.1%, n = 84) was the most common reason for referral.

Conclusion

A variety of minor oral surgery procedures can be provided under local anaesthesia with acceptable accessibility and shorter public oral surgery waiting lists.
Knee Reconstruction Using3D‐PrintedPorous Tantalum Augment in the Treatment of Charcot Joint
Authors: Hua Long , Lei Pengfei , Hu Yihe
Published: September 2022

Background

Charcot joint disease is a rare neurogenic lesion of the joint characterized by progressive joint destruction with dislocation or subluxation. However, whether a joint replacement should be performed for severe joint damage is controversial.

Case presentation

This paper reports a case of severe Charcot joint disease with a large bone defect that was treated with arthroplasty assisted by a customized 3D‐printed porous tantalum. The patient was admitted to the hospital with a 9‐year history of bilateral knee pain that had aggravated in the past 2 months. Radiography showed osteogeny and sclerosis in both knees, free bone fragments, heterotopic ossification, new bone, and osteophyte formation, irregular margins, apparent narrowing of joint space, and severe joint damage (Anderson Orthopedic Research Institute classification type III). Based on the present illness, history, imaging, and laboratory examination, Charcot joint disease was confirmed. Conservative treatment has been reported in the literature. There are limited reports on the surgical treatment of severe Charcot joint disease. We followed up with the patient for a year after the operation, and the imaging and clinical evaluation results were good. Postoperative X‐ray examinations showed good alignment of force lines, good joint space, and no evidence of loosening. The patient was mobile and did not need crutches.

Conclusions

Through accurate surgical evaluation and preparation of 3D‐printed porous tantalum implants, severe AORI classification type III Charcot joint disease can effectively restore the range of motion of the knee joint, the lower limb alignment, and finally achieve good functional results of walking without crutches.
Trans‐right atrial access to the left ventricle for catheter ablation of ventricular tachycardia in patients with mechanical aortic and mitral valves
Authors: Gökdeniz Teyyar , Karavelioglu Yusuf , Akgün Taylan , Çelik Muhammet Cihat
Published: September 2022

The presence of mechanical heart valves in both aortic and mitral positions is a significant limitation for traditional left ventricular (LV) access, including retrograde transaortic and/or antegrade interatrial transseptal routes. We present a case of successful catheter ablation for ventricular tachycardia via a traditional transfemoral venous approach, which involves direct puncture of the inferior and medial aspect of the right atrium adjacent to the posteroseptal process of LV (PSPLV). Percutaneous trans‐right atrial access to the left ventricle appears to be a safe and feasible method for catheter ablation of ventricular tachycardia in patients with mechanical aortic and mitral valves.
Diagnostic progression to schizophrenia: A nationwide cohort study of 11 170 adolescents and young adults with autism spectrum disorder
Authors: Hsu Tien‐Wei , Chu Che‐Sheng , Tsai Shih‐Jen , Hsu Ju‐Wei , Huang Kai‐Lin , Cheng Chih‐Ming , Su Tung‐Ping , Chen Tzeng‐Ji , Bai Ya‐Mei , Liang Chih‐Sung , Chen Mu‐Hong
Published: September 2022

Aims

Previous studies have suggested an increased risk of developing schizophrenia later in life in children with autism spectrum disorder (ASD). This study aims to investigate the diagnosis stability and the potential predictors for progression to schizophrenia in ASD.

Methods

We recruited 11 170 adolescents (10–19 years) and young adults (20–29 years) with ASD between 2001 and 2010. They were followed up to the end of 2011 to identify newly diagnosed schizophrenia. The Kaplan–Meier method and Cox regression with age as a time scale were employed to estimate incidence rates and the significance of candidate predictors.

Results

The progression rate from ASD to schizophrenia was 10.26% for 10 years of follow‐up. Among 860 progressors, 580 (67.44%) occurred within the first 3 years after a diagnosis of ASD. The identified predictors were age (reported as hazard ratio with 95% confidence interval: 1.13; 1.11–1.15), depressive disorder (1.36; 1.09–1.69), alcohol use disorder (3.05; 2.14–4.35), substance use disorder (1.91; 1.18–3.09), cluster A personality disorder (2.95; 1.79–4.84), cluster B personality disorder (1.86; 1.05–3.28), and a family history of schizophrenia (2.12; 1.65–2.74).

Conclusion

More than two‐thirds of the progressors developed schizophrenia within the first 3 years. Demographic characteristics, physical and psychiatric comorbidities, and psychiatric family history were significant predictors of progression.
Internet searching on the head louse in the UK since the COVID‐19 pandemic
Authors: Walker Mark David , Sulyok Mihály
Published: September 2022

Background

Wide‐ranging restrictions on social and educational activities were imposed in 2020 in response to the COVID‐19 pandemic. These likely influenced the population dynamics of the head louse. Close physical contact between human hosts is required for transmission of this ectoparasite.

Method

Pre‐ and post‐pandemic internet interest in the head louse in the UK was compared using Google Trends data from March 2017 to March 2022 and modeling using the Meta Prophet package. The influence of school holidays and school attendance was also investigated.

Results

There was a sharp decline in internet searching of the term “head louse” from March 2020 onwards coinciding with COVID‐19 restrictions, and a large difference between pre‐ and post‐pandemic search volumes. No influence of school holidays or attendance on internet searching on the head louse was found.

Conclusion

The results suggest pandemic restrictions have had a large effect on head louse incidence.
Understanding How a New Hachimoji Nucleobase Alters Photodynamics of Genetic Building Blocks†
Authors: de Vries Mattanjah S.
Published: September 2022

This article is a highlight of the paper by Krul et al. in this issue of Photochemistry and Photobiology. It describes the excited state dynamics of 5‐aza‐7‐deazaguanine (5N7CG), which has recently been proposed as an alternative nucleobase. Upon UV absorption to the lowest energy 1ππ* state, 5N7CG returns to the electronic ground state an order of magnitude more slowly than guanine with a corresponding greater fluorescence quantum yield. These findings are significant because they suggest that 5N7CG is less UV photostable than its canonical nucleobase equivalent, which would have been a selective disadvantage in prebiotic conditions.
Comprehensive prediction of plant cytoplasmic and apoplastic effectors underlying Erwinia psidii pathogenicity
Authors: Alves Francisco Henrique Nunes da Silva , Pereira Isadora Cristófoli , dos Santos Samuel Alves , Monteiro Ana Leticia Rocha , Vidigal Pedro Marcus Pereira , Alfenas Acelino Couto , Badel Jorge Luis
Published: September 2022

Erwinia psidii (Eps) is the causal agent of emerging diseases of eucalypt and guava; however, the mechanisms underlying its pathogenicity are not fully understood. Here, we predicted factors involved in the ability of Eps to cause disease on its host plants. For that, the genomes of four Eps strains exhibiting different virulence on eucalypt were sequenced, and hrp/hrc genes coding for the type III secretion system (T3SS), effectors injected into the plant cell cytoplasm through the T3SS (T3SEs) and their plant subcellular localizations, as well as proteins deployed to the host apoplast, were predicted. It was found that Eps possesses a complete hrp/hrc gene cluster based on comparison with Erwinia amylovora. A total of 18 T3SEs were predicted, 11 of which were shared among all strains, none were exclusive to any strain and seven were absent in at least one strain. No sequence variation among strains was found for five T3SE candidates whereas extensive variation was found for six, suggesting the latter may be determinants of virulence differences. The T3SE candidates are predicted to target the plant cell nucleus, cytoplasm, mitochondrion, chloroplast and peroxisome. The predicted apoplastic effector repertoire common to all four strains was over‐represented in proteins of unknown functions or predicted to possess enzymatic activities, among which the most abundant were oxidoreductases and peptidases. Proteins with lytic transglycosylase activity were predicted in strain‐specific apoplastic effector repertoires. These results provide an important framework for future research aimed at uncovering the factors underlying Eps pathogenicity.
Understanding policy influence in hybrid regimes: Insights from a qualitative study of policy advice in Ukraine and Moldova
Authors: Marchevska Denitsa , Steen Trui
Published: September 2022

The growing complexity of policy challenges has necessitated the reconsideration of the classic state‐centered deliberative models and their replacement with more inclusive concepts like that of the policy advisory system. Still, although the asymmetrical power distribution across different advisors has been recognized, the question of why some actors are able to exercise greater influence than others has received relatively little systematic attention. This paper addresses this question while focusing its attention on Ukraine and Moldova in a departure from the literature's empirical preoccupation with Western liberal democracies. Through a qualitative analysis of 45 semi‐structured interviews, the paper empirically tests the theoretical conceptualization, which explains policy influence as a result of the interaction of content, context, demand and supply factors. The findings illustrate the usefulness of the framework as a theoretical tool beyond Western democratic systems. However, they also indicate the need for conceptual refinements accounting for the significant role played by internationalization, personalization, informality, politicization and political polarization in advisory dynamics in hybrid regimes like those in Ukraine and Moldova in order for advisory scholarship to overcome its Western bias.
Contract as a Transfer of Ownership and Public Justification: Two Models
Authors: Zanitelli Leandro Martins
Published: September 2022

This article deals with Peter Benson’s claim that, unlike rival approaches such as promissory morality and the economic analysis of law, the theory of contract as transfer of ownership offers a public basis of justification for the coercive practice of contracts. The article points out that this claim can be understood in two ways, each corresponding to a model of public justification, namely, the avoidance model and the hermeneutic model. My ambition is to show that the avoidance model is beset by certain difficulties not encountered by the hermeneutic model, suggesting that the hermeneutic model is a more promising interpretation of the idea of public justification as applied to contracts.
W. E. B. Du Bois and the EVOLUTION OF ‘RACE’
Authors: Shaw Stephanie J.
Published: September 2022

This essay situates the major works of W.E.B. Du Bois and some of his minor work between the 1880s and 1940 in the historical context of black people's writing about race since the eighteenth century. In offering examples of the evolution of black thinking and writing on this topic, it views Du Bois's work in the context of Moral and Ethical Philosophy (rather than the more obvious History, Sociology, and Political Economics) in order to reveal his efforts as a disruption, deliberately designed to shift the discussions of race and race relations from defense to offense, which he did most explicitly and profoundly in Dusk of Dawn (1940) but had been doing much more subtly throughout his scholarly career.
Injury characteristics and circumstances of firearm trauma: Assessing suicide survivors and decedents
Authors: Karnick Aleksandr T. , Bond Allison E. , Kaufman Elinore J. , Anestis Michael D. , Capron Daniel W.
Published: September 2022

Introduction

Despite representing fewer than 5% of suicide attempts, firearms account for over half of deaths. Yet there is little clinical information regarding firearm attempts, particularly survivors. We assessed clinical factors differentiating firearm suicide survivors from decedents, firearm attempters from other methods, and firearm attempters from similarly injured trauma patients.

Methods

We used clinical data from the National Trauma Data Bank (2017) to assess firearm suicide attempts using cross‐sectional and case–control designs. We used logistic and multinomial regression to compare groups and assess firearm type and discharge destination.

Results

Older age, being uninsured, and injury location were associated with increased mortality among firearm attempters. Older age, White race, male sex, and being uninsured were associated with firearm attempts. Major psychiatric disorders were associated with firearm attempts and using a rifle or shotgun. Major psychiatric disorders, female sex, and smoking were associated with psychiatric discharge. Black and other race were associated with law enforcement discharge, and Black race was associated with lower odds of psychiatric discharge. Uninsured patients had lower odds of discharge to long‐term care, psychiatric, or rehabilitation facilities.

Conclusions

This study identifies factors associated with firearm suicide and includes indicators of disparities in health services for patients at high risk of suicide death.
The novel HLA‐B*52:110N allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual
Authors: Zhang Jian‐hua , Zheng Zhong‐zheng , Du Ke‐ming , An Lin , Yang Lin‐hua
Published: September 2022

HLA‐B*52:110N differs from HLA‐B*52:01:01:01 by one nucleotide in exon 3.
Genomic sequence of the HLA‐A*01:109 allele identified in a solid organ donor
Authors: Kumar Prabin , Chaudhary Akshay , Makwana Mayur , Thanki Kajal , Parekh Khushagra
Published: September 2022

The full‐length genomic sequence of the HLA‐A*01:109 allele identified in a solid organ donor.
Characterization of two new HLA class I alleles: HLA‐A*02:1065 and HLA‐C*02:216N
Authors: Loginova Maria , Druzhinina Svetlana , Paramonov Igor
Published: September 2022

Two new HLA alleles were identified during routine next generation sequencing.
The natural cytotoxicity receptor genes in the family Felidae
Authors: Bubenikova Jana , Futas Jan , Oppelt Jan , Plasil Martin , Vodicka Roman , Burger Pamela A. , Horin Petr
Published: September 2022

Natural killer (NK) cells belong to the innate immune system. The germline‐encoded natural killer cell receptors represent activating and inhibitory receptors regulating multiple NK cell activities. The natural cytotoxicity receptors (NCRs) are activating natural cytotoxicity triggering receptors 1, 2, and 3 (NKp46, NKp44, and NKp30), encoded by the genes NCR1, NCR2, and NCR3, respectively. NCRs may be expressed in different cell types engaged in mechanisms of innate and adaptive immunity. The family Felidae, comprising the domestic cat and a wide variety of free‐ranging species represents a well‐suited model for biomedical and evolutionary studies. We characterized the NCR1, NCR2, and NCR3 genes in a panel of felid species. We confirmed the presence of potentially functional genes NCR1, NCR2, and NCR3 in all species. All three genes are conserved within the family and are similar to other phylogenetically related mammalian families. The NCR1 and NCR2 phylogenetic trees based on both nucleotide and protein sequences corresponded to the current zoological taxonomy, with some exceptions suggesting effects of different selection pressures in some species. Highly conserved NCR3 sequences did not allow a robust phylogenetic analysis. Most interspecific differences both at the nucleotide and protein level were found in NCR2. Within species, the most polymorphic CDS was detected in NCR1. Selection analyses indicated the effects of purifying selection on individual amino acid sites in all three genes. In stray cats, a rather high intraspecific diversity was observed.
Divergent splanchnic sympathetic efferent nerve pathways regulate interleukin‐10 and tumour necrosis factor‐α responses to endotoxaemia
Authors: McKinley Michael J. , Martelli Davide , Trevizan‐Baú Pedro , McAllen Robin M.
Published: September 2022

The efferent branches of the splanchnic sympathetic nerves that enhance interleukin‐10 (IL‐10) and suppress tumour necrosis factor‐α (TNF) levels in the reflex response to systemic immune challenge were investigated in anaesthetized, ventilated rats. Plasma levels of TNF and IL‐10 were measured 90 min after intravenous lipopolysaccharide (LPS, 60 µg/kg). Splanchnic nerve section, ganglionic blockade with pentolinium tartrate or β2 adrenoreceptor antagonism with ICI 118551 all blocked IL‐10 responses. Restoring plasma adrenaline after splanchnic denervation rescued IL‐10 responses. TNF responses were disinhibited by splanchnic denervation or pentolinium treatment, but not by ICI 118551. Splanchnic nerve branches were cut individually or in combination in vagotomized rats, ruling out any vagal influence on results. Distal splanchnic denervation, sparing the adrenal nerves, disinhibited TNF but did not reduce IL‐10 responses. Selective adrenal denervation depressed IL‐10 but did not disinhibit TNF responses. Selective denervation of either spleen or liver did not affect IL‐10 or TNF responses, but combined splenic and adrenal denervation did so. Finally, combined section of the cervical and lumbar sympathetic nerves did not affect cytokine responses to LPS. Together, these results show that the endogenous anti‐inflammatory reflex is mediated by sympathetic efferent fibres that run in the splanchnic, but not other sympathetic nerves, nor the vagus. Within the splanchnic nerves, divergent pathways control these two cytokine responses: neurally driven adrenaline, acting via β2 adrenoreceptors, regulates IL‐10, while TNF is restrained by sympathetic nerves to abdominal organs including the spleen, where non‐β2 adrenoreceptor mechanisms are dominant.

image

Key points

An endogenous neural reflex, mediated by the splanchnic, but not other sympathetic nerves, moderates the cytokine response to systemic inflammatory challenge. This reflex suppresses the pro‐inflammatory cytokine tumour necrosis factor‐α (TNF), while enhancing levels of the anti‐inflammatory cytokine interleukin‐10 (IL‐10).

The reflex enhancement of IL‐10 depends on the splanchnic nerve supply to the adrenal gland and on β2 adrenoreceptors, consistent with mediation by circulating adrenaline. After splanchnic nerve section it can be rescued by restoring circulating adrenaline.

The reflex suppression of TNF depends on splanchnic nerve branches that innervate abdominal tissues including, but not restricted to, spleen: it is not blocked by adrenal denervation or β2 adrenoreceptor antagonism.

Distinct sympathetic efferent pathways are thus responsible for pro‐ and anti‐inflammatory cytokine components of the reflex regulating inflammation.
La ciudad de 15 minutos en Chile: análisis empírico para Gran Santiago, Concepción y Valparaíso
Authors: Correa Parra Juan , Vergara Perucich Francisco , Aguirre Núñez Carlos
Published: September 2022

Se plantea como objetivo de esta investigación la evaluación de las áreas metropolitanas de Santiago, Valparaíso y Concepción, con el fin de caracterizar las composiciones sociodemográficas de los sectores con mayor posibilidad de avance hacia la implementación de la ciudad de 15 minutos. Para ello, se realizó un levantamiento cartográfico de 24 funciones urbanas esenciales a menos de 15 minutos. Luego se construyeron perfiles sociodemográficos de dichas áreas, y como resultado se obtuvo un conjunto de mapas que visibilizan los barrios de cada ciudad donde es más factible implementar ciudades de 15 minutos. Los resultados reflejan la diferencia en la composición sociodemográfica de cada barrio para las áreas metropolitanas estudiadas. El aporte de este estudio es revisar la distancia que puede existir entre las conformaciones urbanas actuales de estas áreas metropolitanas, para proyectar un entorno de ciudad sustentable como el que pregonan las ciudades de 15 minutos
Desafíos de la gestión territorial integral, para la implementación de estrategias de adaptación al cambio climático
Authors: Segura Guerrero Edwin , López Bernal Oswaldo , Figueroa Casas Apolinar
Published: September 2022

La adaptación al cambio climático, como construcción social, trae consigo una brecha en donde las comunidades no tienen el suficiente nivel de influencia en la transformación de los sistemas territoriales, en parte debido a la perspectiva top-down con la que opera la gestión territorial tradicional, dificultando el éxito en la implementación de estrategias de adaptación. El presente artículo propone la gestión territorial integral, como el mecanismo conceptual mediante el cual se pueden incorporar las iniciativas locales de adaptación a la toma de decisiones, a partir del análisis sistemático de dos casos de estudio: Carahatas, Santa Clara (Cuba) y Las Américas, Yumbo (Colombia). A partir de aquí se concluye sobre los principales elementos que deben ser replanteados en el modelo de gestión tradicional, señalando especialmente los principales desafíos que deben superarse para la implementación de estrategias de adaptación de base comunitaria, y su futuro reconocimiento e integración institucional.
Inmovilidad residencial en áreas pericentrales urbanas en transformación: la zona del Restrepo en Bogotá
Authors: Camargo Sierra Angélica Patricia
Published: September 2022

Este artículo analiza las dinámicas de movilidad residencial y las transformaciones recientes de las antiguas periferias urbanas en las ciudades de América Latina, en particular, la zona del Restrepo en Bogotá. Actualmente, estas zonas comportan procesos de densificación y diversificación socioeconómica asociadas con una mejor posición relativa en la ciudad. Aunque confluyen diversas trayectorias residenciales, la zona presenta una mayor inmovilidad residencial con respecto a otras periferias antiguas. A partir del análisis de entrevistas realizadas a residentes de este sector, se identificaron relaciones recíprocas entre las inmovilidades residenciales y las transformaciones territoriales. Se concluye que en el mismo territorio conviven historias de inmovilidad, asociadas a procesos de precarización y de ascenso social y residencial. Las permanencias evidencian la diversidad de vínculos con el territorio y explican las elecciones residenciales
Ilegalidad urbana y producción del espacio en el borde del río Las Ceibas en la ciudad de Neiva, Huila
Authors: Trujillo Quintero John Jairo
Published: September 2022

Asignar la categoría de ilegalidad a un territorio tiene incidencia en la profundización de la desigualdad en la producción de los espacios urbanos. La presente investigación analiza las consecuencias de la categoría jurídica de ilegalidad en la producción del espacio urbano del río Las Ceibas en Neiva (Huila), a través de la comparación de un asentamiento ilegal (Bajo Tenerife) y un barrio legalizado (José Eustasio Rivera). El estudio se realizó con un enfoque cualitativo, adoptando como estrategia metodológica el estudio de caso. La investigación permitirá aportar al debate en la forma de concebir e intervenir los espacios urbanos, a través de políticas públicas inclusivas que superen la dicotomía de legalidad e ilegalidad urbana para motivar la actuación del Estado
Sistemas inteligentes de movilidad urbana en Río de Janeiro: una evaluación crítica
Authors: Costa Aldenilson
Published: September 2022

El uso del potencial del big data presenta retos para la gestión de las ciudades, sobre todo cuando se introducen sistemas inteligentes en el sistema de movilidad que afectan la vida y los desplazamientos de las personas en las ciudades. El objetivo del presente análisis es evaluar los sistemas inteligentes de movilidad urbana de la ciudad de Río de Janeiro. La metodología parte del reconocimiento de datos de las aplicaciones de movilidad, sumados a datos del sistema de metro, tranvía y bicicletas compartidas, que permiten identificar los distintos sistemas inteligentes y su espacialidad en el territorio de la ciudad. El resultado revela que existe una espacialidad selectiva de los sistemas inteligentes de movilidad en Río de Janeiro, que privilegia a algunos barrios según criterios que no corresponden a las demandas de la población, y muestra la necesidad de romper con el patrón histórico excluyente de movilidad.
Quantification of Autoignition Risk in Aeroderivative Gas Turbine Premixers Using Incompletely Stirred Reactor and Surrogate Modeling
Authors: Iavarone Salvatore , Gkantonas Savvas , Jella Sandeep , Versailles Philippe , Yousefian Sajjad , Monaghan Rory F. D. , Mastorakos Epaminondas , Bourque Gilles
Published: September 2022

The design and operation of premixers for gas turbines must deal with the possibility of relatively rare events causing dangerous autoignition (AI). Rare AI events may occur in the presence of fluctuations of operational parameters, such as temperature and fuel composition, and must be understood and predicted. This work presents a methodology based on incompletely stirred reactor (ISR) and surrogate modeling to increase efficiency and feasibility in premixer design optimization for rare events. For a representative premixer, a space-filling design is used to sample the variability of three influential operational parameters. An ISR is reconstructed and solved in a postprocessing fashion for each sample, leveraging a well-resolved computational fluid dynamics solution of the non-reacting flow inside the premixer. Via detailed chemistry and reduced computational costs, ISR tracks the evolution of AI precursors and temperature conditioned on a mixture fraction. Accurate surrogate models are then trained for selected AI metrics on all ISR samples. The final quantification of the AI probability is achieved by querying the surrogate models via Monte Carlo sampling of the random parameters. The approach is fast and reliable so that user-controllable, independent variables can be optimized to maximize system performance while observing a constraint on the allowable probability of AI.
On the Pneumatic Hammer of Hybrid Gas Bearings: Measurements and Predictions
Authors: Jung Hyunsung , Sin Seki , Kim Kyuman , Heo Junwon , Wee Minsoo , Ryu Keun
Published: September 2022

Hybrid bearings integrating an external pressurizing source are widely used in high-speed turbomachinery due to their notable advantages, including low friction and wear, enhanced reliability and durability, and accurate rotor positioning, as well as large static stiffness and load carry capacity even lubricated with low viscosity liquids. This paper reports experimental data and predictions to identify the characteristics of pneumatic hammer of hybrid gas bearings, 60 mm in diameter, with increasing feed gas pressures. Pneumatic hammer characteristics with static load stiffnesses and flow rates of the test bearing are recorded for increasing static loads with various shaft center positions. A computational program for modeling of hybrid gas bearings predicts static load characteristics of the test bearings. Predictions show a remarkable agreement with measurements. Comparisons of measurements and predictions reveal that calculated reduced damping factors and damping coefficients of hybrid bearings, relying on volume ratio between recess and fluid film, are reliable indicators to estimate the onset condition of pneumatic hammer instability.
Estimation of Resultant Airframe Forces for a Variable Pitch Fan Operating in Reverse Thrust Mode
Authors: Rajendran David John , Tunstall Richard , Pachidis Vassilios
Published: September 2022

The resultant forces with a reverse thrust variable pitch fan (VPF) during the aircraft landing run are computed from the installed reverse thrust flow field obtained from an airframe-engine-VPF research model. The research model features a reverse flow capable VPF design in a future, geared, high-bypass ratio 40,000 lbf engine as installed onto a twin-engine airframe in landing configuration, complete with a rolling ground plane to mimic the runway. The reverse thrust flow field during the aircraft landing run is obtained from the three-dimensional RANS/URANS solutions of the model. The evolution of the installed dynamic reverse thrust flow field is characterized by the interaction of the VPF-induced reverse flow with the freestream. Several flow features like reverse flow wash-down by the freestream, external swirling helical flow development, pylon flow obstruction, 180 deg flow turn into the engine, subsequent separated flows, wake interactions, and multipass recirculating flows are observed. The resultant airframe forces due to the reverse thrust flow field are estimated by adaptations of momentum-based far-field and near-field methods. In the active thrust reverser engagement regime of 140 to 40 knots, the VPF generates a sufficient axial airframe decelerating force in the range of 45% to 8% of maximum takeoff thrust. A drag decomposition study and a notional “blocked-fan” analysis are described to understand the stack-up of the axial decelerating force. Additionally, the resultant force has a landing speed-dependent lateral force component because of the pylon obstruction-induced flow nonuniformity. A beneficial downforce component due to upward deflection of streamlines is also observed. The quantification of the resultant forces from the baseline installed airframe-engine-VPF reverse thrust flow field is a necessary step to explore the feasibility of the VPF reverse thrust system for future efficient turbofan architectures, understand force generation mechanisms, and to identify areas for subsequent design improvement.
An Improved Particle Impact Model by Accounting for Rate of Strain and Stochastic Rebound
Authors: Whitaker Steven M. , Bons Jeffrey P.
Published: September 2022

A methodology for informing physics-based impact and deposition models through the use of novel experimental and analysis techniques is presented. Coefficient of restitution (CoR) data were obtained for Arizona Road Dust (ARD), AFRL02 dust, and each component of AFRL02 impacting a Hastelloy X plate at a variety of flow temperatures (295–866 K), surface temperatures (295–1255 K), particle velocities (0–100 m/s), and impact angles (0–90 deg). High speed particle shadow velocimetry (PSV) allowed individual impact data to be obtained for more than 8 million particles overall, corresponding to 20 combinations of particle composition, flow temperature, and surface temperature. The experimental data were applied to an existing physics-based particle impact model to assess its ability to accurately capture the physics of particle impact dynamics. Using the experimental data and model predictions, two improvements to the model were proposed. The first defined a velocity-dependent “effective yield strength,” designed to account for the effects of strain hardening and strain rate during impact. The second introduces statistical spread to the model output, accounting for the effect of randomizing variables such as particle shape and rotation. Both improvements were demonstrated to improve the model predictions significantly. Applying the improved model to the experimental data sets, along with known temperature-dependent material properties such as the elastic modulus and particle density, allowed the temperature dependence of the effective yield strength to be determined. It was found that the effective yield strength is not a function of temperature over the range studied, suggesting that changes in other properties are responsible for differences in rebound behavior. The improved model was incorporated into a computational simulation of an impinging flow to assess the effect of the model improvements on deposition predictions, with the improved model obtaining deposition trends that more closely match what has been observed in previous experiments. The work performed serves as a stepping stone towards further improvement of physics-based impact and deposition models through refinement of other modeled physical processes.
Profile Loss Reduction of High-Lift Turbine Blades With Rough and Ribbed Surfaces
Authors: Sivaramakrishnan Malathi Ananth , Nardini Massimiliano , Vaid Aditya , Rao Vadlamani Nagabhushana , Sandberg Richard D.
Published: September 2022

Transitional boundary layers on low-pressure turbines (LPTs) are prone to separation on the suction surface of the blade under strong local adverse pressure gradients. Intermittent freestream turbulence, periodic wakes shed by the upstream blades, and surface roughness due to in-service degradation of the blades are shown to suppress the separation. Although this generally leads to a profile loss reduction, some of the benefits are offset by a loss increase associated with an increased turbulent wetted area. In this work, we explore a strategy where the losses in both the transitional and turbulent boundary layers can be reduced. In particular, we employ surface roughness in the transitional regime to reduce the separation bubble-related losses and riblets in the turbulent regime to further reduce the losses due to the turbulent wetted area. The efficacy of this ‘rough-riblet blade surface’ is studied using high-fidelity eddy resolving simulations on the configuration of a flat surface subjected to streamwise varying pressure gradients. Two riblet shapes, sawtooth and scalloped, are considered. When compared to the roughness alone configuration, scalloped riblets reduced the skin friction drag by ≈10% and are much more effective than the sawtooth riblets. Through the streamwise evolution of the boundary layer parameters such as trailing edge momentum thickness, maximum turbulent kinetic energy, and Reynolds stresses, the additional losses incurred at the junction between the smooth wall and riblet leading edge are highlighted.
Effect of Mixing on the Anchoring and Combustion Regimes of Pure Hydrogen Flames in Sequential Combustors
Authors: Solana-Pérez R. , Shcherbanev S. A. , Ciani A. , Noiray N.
Published: September 2022

In this work, we perform an experimental study of the combustion of pure hydrogen in the sequential stage of a generic combustor. This academic test rig is a simplified model of an industrial sequential combustor. The sequential fuel is injected using different injector geometries. The composition and temperature of the hot stream at the inlet of the sequential burner are defined by the mass flows of the hot combustion products from the first stage (30 kW natural gas–air flame with equivalence ratio of 0.7) and of the dilution air. This temperature is varied between 1100 K and 850 K by modifying the dilution air mass flow in order to study the different combustion regimes of the sequential hydrogen flame. High-speed imaging of OH radicals chemiluminescence is performed with optical emission spectroscopy to measure vitiated gas temperatures. In particular, we investigate the transition from a flame anchored in the sequential combustion chamber, to the situation where it stabilizes upstream into the mixing section, when the inlet flow temperature is increased. Of particular interest is the increasing rate of formation of auto-ignition kernels in this transition process. The underlying combustion regime change is analyzed with 0D reactor simulations, and the limitations of such a simplified low-order model of the flame location are discussed. The effects and importance of the mixing process between fresh fuel and the hot vitiated coflow are examined. Two different injectors are compared under the same operating conditions that create different flow structures along the mixing section. As a result of that, they provide different degrees of mixing between the hydrogen and the hot vitiated flow and allow to demonstrate the impact of mixing quality on the flame morphology.
Optimization of Temperature Field by Differentiating Number of Circumferential Control Zones in Local Post Weld Heat Treatment on 9%Cr Heat-Resistant Steel Pipe
Authors: Zhou Fan , Wang Xue , Xu Qiang , Zhang Da
Published: September 2022

This paper reports the optimal use of control zones to achieve required uniformity of temperature distribution in local postweld heat treatment of welds in 9% Cr heat-resistant large pipe system. In this research, local post weld heat treatment tests on temperature distribution with different control zones were carried out on 9%Cr steel pipes (OD 710 mm × 35 mm and OD 575 mm × 35 mm), which was further used for the development of the thermal analysis of the postweld heat treatment model via abaqus. The research results revealed (1) the effect of number of control zone on the uniformity of temperature distribution; (2) the effect of size of pipe diameter on the circumferential temperature and the through-thickness temperature gradients. This article discusses the possible reasons for the temperature difference at various positions of the pipe caused by the air flow inside the pipe with different control zones. Based on the obtained results, a practical method was designed for the selection the number of circumferential control zones on 9%Cr heat-resistant steel pipeline according to the required degree of temperature distribution uniformity. This paper contributes to the specific knowledge and the generic methodology.
Two mental models of integrated care for advanced liver disease: qualitative study of multidisciplinary health professionals
Authors: Arney Jennifer , Gray Caroline , Walling Anne M , Clark Jack A , Smith Donna , Melcher Jennifer , Asch Steven , Kanwal Fasiha , Naik Aanand D
Published: September 2022

Objectives

The purpose of this paper is to present two divergent mental models of integrated advanced liver disease (AdvLD) care among 26 providers who treat patients with AdvLD.

Setting

3 geographically dispersed United States Veterans Health Administration health systems.

Participants

26 professionals (20 women and 6 men) participated, including 9 (34.6%) gastroenterology, hepatology, and transplant physicians, 2 (7.7%) physician assistants, 7 (27%) nurses and nurse practitioners, 3 (11.5%) social workers and psychologists, 4 (15.4%) palliative care providers and 1 (3.8%) pharmacist.

Main outcome measures

We conducted qualitative in-depth interviews of providers caring for patients with AdvLD. We used framework analysis to identify two divergent mental models of integrated AdvLD care. These models vary in timing of initiating various constituents of care, philosophy of integration, and supports and resources needed to achieve each model.

Results

Clinicians described integrated care as an approach that incorporates elements of curative care, symptom and supportive care, advance care planning and end-of-life services from a multidisciplinary team. Analysis revealed two mental models that varied in how and when these constituents are delivered. One mental model involves sequential transitions between constituents of care, and the second mental model involves synchronous application of the various constituents. Participants described elements of teamwork and coordination supports necessary to achieve integrated AdvLD care. Many discussed the importance of having a multidisciplinary team integrating supportive care, symptom management and palliative care with liver disease care.

Conclusions

Health professionals agree on the constituents of integrated AdvLD care but describe two competing mental models of how these constituents are integrated. Health systems can promote integrated care by assembling multidisciplinary teams, and providing teamwork and coordination supports, and training that facilitates patient-centred AdvLD care.
Clinical features of COVID-19 patients with rebound phenomenon after corticosteroid therapy
Authors: Murakami Koji , Sano Hirohito , Tode Naoki , Tsukita Yoko , Sato Kei , Narita Daisuke , Kimura Nozomu , Matsumoto Shuichiro , Ono Yoshinao , Iwasaki Chikashi , Sugiyama Hatsumi , Suzuki Manami , Kakuto Sho , Konno Shuichi , Kanamori Hajime , Baba Hiroaki , Oshima Kengo , Takei Kentarou , Tokuda Koichi , Tamada Tsutomu , Sugiura Hisatoshi
Published: September 2022

Rational

Corticosteroid therapy plays a key role in the treatment of COVID-19 patients with respiratory failure. However, a rebound phenomenon after steroid cessation rarely occurs. Here, we investigated the clinical features of patients with rebound after steroid therapy.

Methods

In total, 84 patients with COVID-19 treated with corticosteroids were enrolled and analysed retrospectively. A rebound was defined as when a patient’s respiratory status deteriorated after the cessation of corticosteroid therapy, without secondary bacterial infection.

Results

Subjects in the rebound group were more likely to having severe respiratory failure than those in the non-rebound group. While the duration of steroid therapy was longer in the rebound group (8 days vs 10 days, p=0.0009), the dosage of steroid and the timing of the start or termination of steroid therapy did not show any differences between the two groups (p=0.17 and 0.68, respectively). The values of soluble interleukin-2 receptor (sIL-2R) at the baseline and the values of C reactive protein (CRP) or lactate dehydrogenase (LDH) at the end of steroid therapy were significantly higher in the rebound group (937 vs 1336 U/mL; p=0.002, 0.63 vs 3.96 mg/dL; p=0.01 and 278 vs 451 IU/mL; p=0.01, respectively). No patient in the rebound group suffered from thromboses, and the causes of death were exacerbation of COVID-19, ventilator-associated pneumonia or sepsis. The prediction model using baseline features for the rebound phenomenon included four variables of age >68 years, required supplemental oxygen >5 L/min, lymphocyte counts <792 /µL and sIL-2R >1146 U/mL. The discrimination ability of this model was 0.906 (0.755–0.968).

Conclusion

These findings suggest that severe respiratory failure has a higher risk for the rebound phenomenon after the cessation of corticosteroids, and the values of sIL-2R, LDH and CRP are useful to assess the probability of developing rebound. A multivariate model was developed to predict rebound risk, which showed acceptable discrimination ability.
Erythrocyte complement receptor 1 (ECR1) and erythrocyte-bound C4d (EC4d) in the prediction of poor pregnancy outcomes in systemic lupus erythematosus (SLE)
Authors: Conklin John , Golpanian Michael , Engel Alexis , Izmirly Peter , Belmont H Michael , Dervieux Thierry , Buyon Jill P , Alexander Roberta Vezza
Published: September 2022

Background

Complement activation has been associated with adverse pregnancy outcomes (APO) in SLE. Pregnant women with SLE were studied to evaluate whether complement dysregulation within the first two pregnancy trimesters predicts APO.

Methods

Pregnant women fulfilled classification criteria for SLE. APO included neonatal death, preterm delivery before 36 weeks and small for gestational age newborn. Pre-eclampsia was also evaluated. Erythrocyte complement receptor 1 (ECR1) and erythrocyte-bound C4d (EC4d) were measured by flow cytometry. Complement proteins C3 and C4 were measured by immunoturbidimetry and anti-double-stranded DNA by ELISA in serum. Statistical analysis consisted of t-test, confusion matrix-derived diagnostic analysis, and multivariate logistic regression.

Results

Fifty-one women had 57 pregnancies and 169 visits during the study. Baseline visits occurred mainly in the first (n=32) and second trimester (n=21). Fourteen (24.6%) pregnancies resulted in 21 APO with preterm delivery being the most common (n=10). ECR1 <5.5 net mean fluorescence intensity in the first trimester predicted APO with a diagnostic OR (DOR) of 18.33 (95% CI: 2.39 to 140.4; t-test p=0.04). Other individual biomarkers did not reach statistical significance. To estimate the likelihood of APO, we developed an algorithm that included the week of pregnancy, ECR1 and EC4d. From this algorithm, a Pregnancy Adversity Index (PAI) was calculated, and a PAI >0 indicated an elevated likelihood of pregnancy complications (DOR: 20.0 (95% CI: 3.64 to 109.97)).

Conclusions

Low levels of ECR1 in early or mid-pregnancy are predictive of an APO. Incorporating the weeks of gestation and both ECR1 and EC4d generated a PAI, which further predicted serious pregnancy complications.
Triple high energy nuclear and hadron collisions - a new method to study QCD phase diagram at high baryonic densities
Authors: Vitiuk O. V. , Pugatch V. M. , Bugaev K. A. , Panasiuk P. P. , Yakovenko N. S. , Grinyuk B. E. , Zherebtsova E. S. , Bleicher M. , Bravina L. V. , Taranenko A. V. , Zabrodin E. E.
Published: September 2022

We propose an entirely new method to study the phase diagram of strongly interacting matter by means of scattering the two colliding beams at the fixed target. Here we present the results of simulations of the most central triple nuclear collisions with the UrQMD 3.4 model for the beam center-of-mass collision energies $$\sqrt{s_{NN}} = 2.76\ \hbox {TeV}$$

s

NN

=
2.76

TeV

and $$\sqrt{s_{NN}} = 200\ \hbox {GeV}$$

s

NN

=
200

GeV

. The main outcome of our modeling is that even at these very high collision energies the initial baryonic charge densities are about 3 times higher than the ones achieved in the ordinary binary nuclear collisions. As a result, for instance, the yields of protons and $$\varLambda $$
Λ
-hyperons are strongly enhanced in the triple nuclear collisions. The other prospective applications of this method are briefly discussed. Among them we consider the low energy collisions of three nuclei of lead, passing through an intermediate system with an electric charge of 246 units which exceeds essentially the critical value of 173 and, hence, this may be of crucial importance to study the spontaneous emission of positron-electron pairs from the vacuum. We present the convincing arguments that the triple nuclear collisions method will allow the high energy nuclear physics community to create a new frontier in the studies of the QCD phase diagram and to lift up these studies to an entirely new level.