bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust Design of a Fuel Cell—Turbocharger Hybrid System
Authors: Giugno Andrea , Mantelli Luca , Traverso Alberto 
Published: April 2021

Abstract
Pressurized solid oxide fuel cell (SOFC) systems are a particularly attractive conversion technology for their high electric efficiency, potential for cogeneration applications, low carbon emissions, and high performance at part-load. In this work, an innovative biofueled hybrid system is considered, where the fuel cell stack is pressurized with a turbocharger, resulting in a system with improved cost effectiveness than a microturbine-based one at small scales. In a previous work, a detailed steady-state model of the system, featuring components validated with industrial data, was developed to simulate the system and analyze its behavior in different conditions. The results obtained from this model were used to create response surfaces capable of evaluating the impact of the main operating parameters (fuel cell area, stack current density, and recuperator (REC) surface) on the performance and the profitability of the plant considering system uncertainties. In this paper, similar but extended response surfaces will be used to perform a multi-objective optimization of the system considering the capital costs of the plant and the net power produced as objectives (turbocharger is fixed in geometry). The impact of the energy market scenario on the optimal design of such a system will be investigated considering its installation in three different countries. Finally, the Pareto front produced by optimization will be used to evaluate the robustness of the top performance solutions.
Comparing Global Spray Combustion Characteristics and Local Shot-to-Shot Variations in a Reacting n-Heptane Spray
Authors: Reggeti Shawn A. , Parker Allen , Wanstall C. Taber , Agrawal Ajay K. , Bittle Joshua A. 
Published: April 2021

Abstract
In support of efforts to develop improved models of turbulent spray behavior and combustion in diesel engines, experimental data and analysis must be obtained for guidance and validation. For Reynolds-averaged Navier–Stokes (RANS)-based Computational fluid dynamics (CFD) modeling approaches, representative ensemble average experimental results are important. For high-fidelity models such as large eddy simulations (LES)-based CFD, precise individual experimental results are desirable. However, making comparisons between a given experiment and LES is a challenge since local parameters cannot be directly compared. In this work, an optically accessible constant pressure flow rig (CPFR) is utilized to acquire diesel-like fuel injection and reaction behavior simultaneously with three optical diagnostic techniques: rainbow Schlieren deflectometry (RSD), OH* chemiluminescence (OH*), and two-color pyrometry (2CP). The CPFR allows a large number of repeated injection experiments to be performed for statistical analysis and convergence using ensemble-averaging techniques, while maintaining highly repeatable test conditions. Even for stable test conditions, variations in local turbulent fuel–air mixing introduce variability, which manifests as significant differences in OH* and 2CP results. Experimental measurements of characteristic parameters including liquid and vapor jet penetration, liftoff length, soot temperature and concentration, and turbulent flame speed, along with the shot-to-shot variability of each dataset, are presented and discussed. A statistical method is utilized to analyze the extent of this variability, and to identify superlative injections within the dataset for discussion and analysis of shot-to-shot variations.
Conceptual Design and Energy Storage Positioning Aspects for a Hybrid-Electric Light Aircraft
Authors: Gkoutzamanis Vasilis G. , Kavvalos Mavroudis D. , Srinivas Arjun , Mavroudi Doukaini , Korbetis George , Kyprianidis Konstantinos G. , Kalfas Anestis I. 
Published: April 2021

Abstract
This work is a feasibility study of a 19-passenger hybrid-electric aircraft, to serve the short-haul segment within the 200–600 nautical miles. Its ambition is to answer some dominating research questions, during the evaluation and design of aircraft based on alternative propulsion architectures. The potential entry into service (EIS) is foreseen beyond 2030. A literature review is performed to identify similar concepts under research and development. After the requirements' definition, the first level of conceptual design is employed. The objective of design selections is driven by the need to reduce CO2 emissions and accommodate aircraft electrification with boundary layer ingestion engines. Based on a set of assumptions, a methodology for the sizing of the hybrid-electric aircraft is described to explore the basis of the design space, incorporating a parametric analysis for the consideration of boundary layer ingestion effects. Additionally, a methodology for the energy storage positioning is provided to highlight the multidisciplinary aspects between the sizing of an aircraft, the selected architecture (series/parallel partial hybrid), and the storage characteristics. The results show that it is not possible to fulfill the initial design requirements (600 nmi) with a fully-electric aircraft configuration, due to the far-fetched battery necessities. It is also highlighted that compliance with airworthiness standards is favored by switching to hybrid-electric aircraft configurations and relaxing the design requirements (targeted range, payload, battery technology). Finally, the lower degree of hybridization (40%) is observed to have a higher energy efficiency (−12% energy consumption) compared to the higher degree of hybridization (50%) and greater CO2 reduction, with respect to the conventional configuration.
Fatigue Testing of Copper Nanoparticle-Based Joints and Bonds
Authors: Sivasubramony Rajesh Sharma , Kokash Maan Zaid , Thekkut Sanoop , Shahane Ninad , Thompson Patrick , Mirpuri Kabir , Kawana Yuki , Greene Christopher M. , Borgesen Peter 
Published: April 2021

Abstract
Fused or sintered Cu nanoparticle structures are potential alternatives to solder for ultrafine pitch flip chip assembly and to sintered Ag for heat sink attach in high-temperature micro-electronics. Meaningful testing and interpretation of test results in terms of what to expect under realistic use conditions do, however, require a mechanistic picture of degradation and damage mechanisms. As far as fatigue goes, such a picture is starting to emerge. The porosity of sintered nanoparticle structures significantly affects their behavior in cycling. The very different sensitivities to parameters, compared to solder, mean new protocols will be required for the assessment of reliability. This study focused on fatigue in both isothermal and thermal cycling. During the latter, all damage occurs at the low-temperature extreme, so life is particularly sensitive to the minimum temperature and any dwell there. Variations in the maximum temperature up to 125 °C did not affect, but a maximum temperature of 200 °C led to much faster damage. Depending on particle size and sintering conditions, deformation and damage properties may also degrade rapidly over time. Our picture allows for recommendations as to more relevant test protocols for vibration, thermal cycling, and combinations of these, including effects of aging, as well as for generalization of test results and comparisons in terms of anticipated behavior under realistic long-term use conditions. Also, the fatigue life seems to vary with the ultimate strength, meaning that simple strength testing becomes a convenient reference in materials and process optimization.
Interleukin-6 mediated exercise-induced alleviation of adiposity and hepatic steatosis in mice
Authors: Li Long , Huang Caoxin , Yin Hongyan , Zhang Xiaofang , Wang Dongmei , Ma Chen , Li Jia , Zhao Yan , Li Xuejun 
Published: April 2021

IntroductionExercise training has been shown to be the most effective strategy to combat obesity and non-alcoholic fatty liver disease. However, exercise promotes loss of adipose tissue mass and improves obesity-related hepatic steatosis through mechanisms that remain obscure.Research design and methodsTo study the role of interleukin-6 (IL-6) in high-fat diet (HFD)-induced adiposity and hepatic steatosis during treadmill running, IL-6 knockout (IL-6 KO) mice and wild-type (WT) mice were randomly divided into lean, obese (fed a HFD) and trained obese groups (fed a HFD and exercise trained).ResultsAfter 20 weeks of HFD feeding and 8 weeks of treadmill running, we found that exercise obviously reduced HFD-induced body weight gain, inhibited visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) expansion and almost completely reversed obesity-related intrahepatic fat accumulation in WT mice. However, IL-6 knockout (IL-6 KO) mice are refractory to the benefits of treadmill training on body weight, VAT and SAT mass elevation, and hepatic steatosis. Moreover, a panel of lipolytic-related and thermogenic-related genes, including ATGL, HSL and PGC-1α, was upregulated in the VAT and SAT of WT mice that received exercise training compared with untrained mice, which was not observed in IL-6 KO mice. In addition, exercise training resulted in a significant inhibition of hepatic peroxisome proliferator-activated receptor gamma (PPAR-γ) expression in WT mice, and these effects were not noted in IL-6 KO mice.ConclusionThese results revealed that IL-6 is involved in the prevention of obesity and hepatic fat accumulation during exercise training. The mechanisms underlying these antiobesity effects may be associated with enhanced lipolysis and thermogenesis in white adipose tissue. The improvement in hepatic steatosis by exercise training may benefit from the marked inhibition of PPAR-γ expression by IL-6.
Regional variation in cardiovascular magnetic resonance service delivery across the UK
Authors: Keenan Niall G , Captur Gabriella , McCann Gerry P , Berry Colin , Myerson Saul G , Fairbairn Timothy , Hudsmith Lucy , O'Regan Declan P , Westwood Mark , Greenwood John P 
Published: April 2021

ObjectivesTo examine service provision in cardiovascular magnetic resonance (CMR) in the UK. Equitable access to diagnostic imaging is important in healthcare. CMR is widely available in the UK, but there may be regional variations.MethodsAn electronic survey was sent by the British Society of CMR to the service leads of all CMR units in the UK in 2019 requesting data from 2017 and 2018. Responses were analysed by region and interpreted alongside population statistics.ResultsThe survey response rate was 100% (82 units). 100 386 clinical scans were performed in 2017 and 114 967 in 2018 (15% 1-year increase; 5-fold 10-year increase compared with 2008 data). In 2018, there were 1731 CMR scans/million population overall, with significant regional variation, for example, 4256 scans/million in London vs 396 scans/million in Wales. Median number of clinical scans per unit was 780, IQR 373–1951, range 98–10 000, with wide variation in mean waiting times (median 41 days, IQR 30–49, range 5–180); median 25 days in London vs 180 days in Northern Ireland). Twenty-five units (30%) reported mean elective waiting times in excess of 6 weeks, and 8 (10%) ≥3 months. There were 351 consultants reporting CMR, of whom 230 (66%) were cardiologists and 121 (34%) radiologists; 81% of units offered a CMR service for patients with pacemakers and defibrillators.ConclusionsThis survey provides a unique, contemporary insight into national CMR delivery with 100% centre engagement. The 10-year growth in CMR usage at fivefold has been remarkable but heterogeneous across the UK, with some regions still reporting low usage or long waiting times which may be of clinical concern.
Margulis lemma and Hurewicz fibration theorem on Alexandrov spaces
Authors: Xu Shicheng , Yao Xuchao 
Published: April 2021

We prove the generalized Margulis lemma with a uniform index bound on an Alexandrov [Formula: see text]-space [Formula: see text] with curvature bounded below, i.e. small loops at [Formula: see text] generate a subgroup of the fundamental group of the unit ball [Formula: see text] that contains a nilpotent subgroup of index [Formula: see text], where [Formula: see text] is a constant depending only on the dimension [Formula: see text]. The proof is based on the main ideas of V. Kapovitch, A. Petrunin and W. Tuschmann, and the following results: (1) We prove that any regular almost Lipschitz submersion constructed by Yamaguchi on a collapsed Alexandrov space with curvature bounded below is a Hurewicz fibration. We also prove that such fibration is uniquely determined up to a homotopy equivalence. (2) We give a detailed proof on the gradient push, improving the universal pushing time bound given by V. Kapovitch, A. Petrunin and W. Tuschmann, and justifying in a specific way that the gradient push between regular points can always keep away from extremal subsets.
Fabrication of Tantalum-Doped Titanium-Oxide Electron-Selective Contacts with High Passivation Quality
Authors: Yamaguchi Seira , Lee Hyunju , Ogura Atsushi , Masuda Atsushi , Ohshita Yoshio 
Published: April 2021

In this paper, we report on the fabrication of Ta-doped TiO2 (TiO2:Ta) electron-selective contacts and their improved passivation qualities. By using thermal atomic layer deposition, 3.5 nm-thick, undoped TiO2 films and 3.5 nm-thick TiO2:Ta films with Ta concentrations of 1.5, 2.8, and 5.5 at.% were formed at 150 °C on n-type crystalline silicon substrates with ∼1 nm-thick chemical SiO2 layers. Rutherford backscattering spectroscopic measurements confirmed the Ta concentrations in the films and uniform distributions of Ta atoms in the films. X-ray photoelectron spectrometry measurements implied that Ta atoms rather cause local structural changes than enter substitutionally into Ti sites. After annealing at 130 °C in air, the effective minority carrier lifetime (τ
eff) of the TiO2:Ta-passivated samples were significantly higher than those of the samples passivated with undoped TiO2 films. The highest τ
eff was obtained for the samples with a relatively low Ta-doping concentration of 1.5 at.%. On the other hand, the passivation quality was degraded by Ta doping with a too high concentration (for example, 18.4 at.%). These results indicate that moderate Ta doping improves the passivation quality of TiO2 thin films.
Prospective Comparison of Moderate Conscious Sedation and Anesthesia Assistance for the Performance of Endoscopic Retrograde Cholangiopancreatography (ERCP)
Authors: Akhter Ahmed , Patel Ravi , Nelsen Eric , Benson Mark E. , Gopal Deepak V. , Soni Anurag , Pfau Patrick 
Published: April 2021

Objectives. Recent trends have favored the use of anesthesia personnel more frequently for advanced endoscopic procedures. We hypothesize a selective sedation approach based on patient and procedural factors using either moderate conscious sedation (MCS) or general anesthesia (GA) will result in similar outcomes and safety with significant cost savings. Methods. A 12-month prospective study of all adult endoscopic retrograde cholangiopancreatography (ERCPs) performed at a tertiary medical center was enrolled. Technical success, cannulation rates, procedural related complications, procedure time, and cost were compared between MCS and GA. Results. A total of 876 ERCPs were included in the study with 74% performed with MCS versus 26% with GA. The intended intervention was completed successfully in 95% of cases with MCS versus 96% cases with GA (

p

= 0.59). Cannulation success rates with MCS were 97.5 versus 97.8% with GA (

p

= 0.81). Overall, adverse event rates were similar in both groups (MCS: 6.6% vs. GA: 9.2%,

p

= 0.21). Mean procedure time was less for MCS versus GA, 18.3 and 26 minutes, respectively (

p

< 0.0001). Selective use of MCS vs. universal sedation with GA resulted in estimated savings of $8,190 per case and $4,735,202 per annum. Conclusions. Preselection of ERCP sedation of moderate conscious sedation versus general anesthesia based upon patient risk factors and planned therapeutic intervention allows for the majority of ERCPs to be completed with MCS with similar rates of technical success and improvement in resource utilization and cost savings compared to performing ERCPs universally with anesthesia assistance.
Inhibition of Granulocytic Myeloid-Derived Suppressor Cells Overcomes Resistance to Immune Checkpoint Inhibition in LKB1-Deficient Non–Small Cell Lung Cancer
Authors: Li Rui , Salehi-Rad Ramin , Crosson William , Momcilovic Milica , Lim Raymond J. , Ong Stephanie L. , Huang Zi Ling , Zhang Tianhao , Abascal Jensen , Dumitras Camelia , Jing Zhe , Park Stacy J. , Krysan Kostyantyn , Shackelford David B. , Tran Linh M. , Liu Bin , Dubinett Steven M. 
Published: April 2021

Abstract

LKB1 inactivating mutations are commonly observed in patients with KRAS-mutant non–small cell lung cancer (NSCLC). Although treatment of NSCLC with immune checkpoint inhibitors (ICI) has resulted in improved overall survival in a subset of patients, studies have revealed that co-occurring KRAS/LKB1 mutations drive primary resistance to ICIs in NSCLC. Effective therapeutic options that overcome ICI resistance in LKB1-mutant NSCLC are limited. Here, we report that loss of LKB1 results in increased secretion of the C–X–C motif (CXC) chemokines with an NH2-terminal Glu-Leu-Arg (ELR) motif in premalignant and cancerous cells, as well as in genetically engineered murine models (GEMM) of NSCLC. Heightened levels of ELR+ CXC chemokines in LKB1-deficient murine models of NSCLC positively correlated with increased abundance of granulocytic myeloid-derived suppressor cells (G-MDSC) locally within the tumor microenvironment and systemically in peripheral blood and spleen. Depletion of G-MDSCs with antibody or functional inhibition via all-trans-retinoic acid (ATRA) led to enhanced antitumor T-cell responses and sensitized LKB1-deficent murine tumors to PD-1 blockade. Combination therapy with anti–PD-1 and ATRA improved local and systemic T-cell proliferation and generated tumor-specific immunity. Our findings implicate ELR+ CXC chemokine-mediated enrichment of G-MDSCs as a potential mediator of immunosuppression in LKB1-deficient NSCLC and provide a rationale for using ATRA in combination with anti–PD-1 therapy in patients with LKB1-deficient NSCLC refractory to ICIs.

Significance:
These findings show that accumulation of myeloid-derived suppressor cells in LKB1-deficient non–small cell lung cancer can be overcome via treatment with all-trans-retinoic acid, sensitizing tumors to immunotherapy.
Grandmaternal Perinatal Serum DDT in Relation to Granddaughter Early Menarche and Adult Obesity: Three Generations in the Child Health and Development Studies Cohort
Authors: Cirillo Piera M. , La Merrill Michele A. , Krigbaum Nickilou Y. , Cohn Barbara A. 
Published: April 2021

Abstract

Background:
Serum DDTs during or just after pregnancy were associated with breast cancer in mothers (F0), and with breast cancer, mammographic density, and obesity in adult daughters (F1) in the Child Health and Development Studies multi-generational cohort in prior publications. Here, we investigate F0 perinatal serum DDT associations with granddaughters'(F2) measured obesity at a median age of 26 and self-reported age at menarche.

Methods:
F2 weight, height and waist circumference were measured by trained examiners. o,p'-DDT, p,p'-DDT and p,p'-DDE were measured in archived F0 perinatal serum. F0 DDT associations with F2 outcomes, accounting for F1 characteristics, were estimated in log-linear models adjusted for F0 and F1 body mass index (BMI), race, and menarche timing (N = 258 triads for obesity; N = 235 triads for early menarche). Interactions between F0 BMI and DDTs were estimated.

Results:
F0 o,p'-DDT was associated with F2 obesity [Odds ratio (OR), 2.6; 95% confidence interval (CI), 1.3–6.7; tertile 3 vs. 1), among normal weight F0 (70%), but not among overweight and obese F0 (Pinteraction = 0.03), independent of other DDTs. F0 o,p'-DDT was also associated with F2 early menarche (OR, 2.1; 95% CI, 1.1–3.9, tertile 3 vs. 1) and this association was not modified by F0 BMI.

Conclusions:
Ancestral exposure to environmental chemicals, banned decades ago, may influence the development of earlier menarche and obesity, which are established risk factors for breast cancer and cardiometabolic diseases.

Impact:
Discovery of actionable biomarkers of response to ancestral environmental exposures in young women may provide opportunities for breast cancer prevention.
See related commentary by Fenton and Boyles, p. 1459
Revision of the Rhagovelia angustipes complex (Insecta: Hemiptera: Veliidae) from Colombia
Authors: GALINDO-MALAGÓN XIMENA ALEJANDRA , MORALES IRINA , MOREIRA FELIPE FERRAZ FIGUEIREDO 
Published: April 2021

Water striders of the genus Rhagovelia Mayr, 1865 (Insecta: Hemiptera: Veliidae) have colonized the water surface mainly in lotic freshwater systems, but also in coastal marine environments. They are characterized by the swimming fan in the distal tarsomere of the middle leg that allows them to quickly maneuver. In the Americas, it was subdivided into four monophyletic complexes (angustipes, collaris, obesa and robusta), one paraphyletic grade (abrupta), each with several groups of species, and one additional group (varipes). However, the taxonomy of this genus still has inconsistencies due to its morphological complexity and to the misinterpretation of characters. For this reason, we present a revision of the species of the angustipes complex occurring in Colombia. Material deposited in nine biological collections was examined, including several types. A total of 3,674 specimens were studied, belonging to 26 valid species, of which R. boyacensis sp. nov., R. graziae sp. nov. and R. molanoi sp. nov., are described as new; and R. angustipes Uhler, 1894 is recorded from the country for the first time. Furthermore, eleven species are redescribed and twelve are considered synonyms. Finally, a key to the species of the angustipes complex occurring in Colombia is presented, as well as updated distribution maps.
The Symptoms-Varices-Pathophysiology classification of pelvic venous disorders: A report of the American Vein & Lymphatic Society International Working Group on Pelvic Venous Disorders
Authors: Meissner Mark H. , Khilnani Neil M. , Labropoulos Nicos , Gasparis Antonios P. , Gibson Kathleen , Greiner Milka , Learman Lee A. , Atashroo Diana , Lurie Fedor , Passman Marc A. , Basile Antonio , Lazarshvilli Zaza , Lohr Joann , Kim Man-Deuk , Nicolini Philippe H. , Pabon-Ramos Waleska M. , Rosenblatt Melvin 
Published: April 2021

[Box: see text] With the support of the American College of Obstetricians and Gynecologists, the American Vein & Lymphatic Society, the American Venous Forum, the Canadian Society of Phlebology, the Cardiovascular and Interventional Radiology Society of Europe, the European Venous Forum, the International Pelvic Pain Society, the International Union of Phlebology, the Korean Society of Interventional Radiology, the Society of Interventional Radiology, and the Society for Vascular Surgery