bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convergence in Sovereign Debt Defaults: Quantifying the Roles of Institutions
Authors: Bhattacharya Mita , Inekwe John 
Published: January 2021

AbstractIn this study, using an ex ante measure, we examine the convergence patterns in sovereign defaults among 101 developing countries for the period from 1990 to 2015. We employ the club convergence algorithm to determine convergence paths across countries and examine the role of institutions in shaping the observed convergence patterns. The merging of clubs reveals three distinct convergent sub‐clubs. Countries in each of these sub‐clubs tend to exhibit a similar pattern of long‐run convergence in cases of sovereign debt default. Countries with better institutions are less likely to belong to a club with greater risks of sovereign defaults by 7% points. Unlike trade openness, levels of external debt, inflation and current account balance increase the probability of default in these economies.
Long‐Term Efficacy of Screw Fixation vs Hemiarthroplasty for Undisplaced Femoral Neck Fracture in Patients over 65 Years of Age: A Systematic Review and Meta‐Analysis
Authors: Xu Wen‐nan , Xue Qing‐yun 
Published: January 2021

ObjectiveTo compare the long‐term efficacy of screw fixation and hemiarthroplasty in elderly patients with undisplaced femoral neck fractures.MethodsWe searched Cochrane Library, EMBASE, and MEDLINE from inception to 10 June 2020 to identify studies about undisplaced femoral neck fracture in elderly patients over 65 years of age. The included studies were assessed by two researchers according to the Cochrane risk‐of‐bias criteria and Newcastle–Ottawa Scale. Meta‐analysis was performed with Revman 5.3 software. The odds ratios (OR) and mean differences (MD) were used to compare dichotomous and continuous variables.ResultsA total of 750 patients were included in this meta‐analysis. In elderly patients, undisplaced femoral neck fracture treated with hemiarthroplasty had a lower implant‐related complication rate (OR, 4.05 [95% CI, 2.38 to 6.89]; P < 0.00001; I2 = 0), lower reoperation rate (OR, 4.88 [95% CI, 2.84 to 8.38]; P < 0.00001; I2 = 0), and superior Harris score (WMD, −5.05 [95% CI, −7.30 to −2.80]; P < 0.0001; I2 = 0) in the early postoperative period. Although screw fixation was associated with shorter operative time (WMD, −36.22 [95% CI, −50.72 to −21.73]; P < 0.00001; I2 = 98%) and less blood loss (WMD, −165.84 [95% CI, −209.29 to −122.38]; P < 0.00001; I2 = 96%), there was no significant difference in long‐term mortality (OR, 0.65 [95% CI, 0.28 to 1.48]; P < 0.31; I2 = 75%) between these two treatments.ConclusionIn elderly patients with undisplaced femoral neck fractures, hemiarthroplasty provided a lower implant‐related complication rate, lower reoperation rate, superior hip function without increased long‐term mortality. Hemiarthroplasty should be recommended as a better alternative in such patients compared with multiple cannulated screws.
Per Pedicel‐Ligament Flavum Tunnel Outside‐In Foraminoplasty for T10–T12 Discectomy under a Percutaneous Endoscope
Authors: Lin Wei , Liu Wei , Ma Wen‐ting , Xue Yuan 
Published: January 2021

ObjectiveTo describe the effectiveness of T10–T12 discectomy and per pedicel‐ligament flavum tunnel outside‐in foraminoplasty protocols under percutaneous endoscope.MethodsThis retrospective study from September 2017 to June 2019 comprised 10 patients (mean age was 64.7 years, with 7 men and 3 women) with symptomatic thoracic disc herniation. Patients who had 12 months of follow‐up and no cervical and lumbar spine surgery or trauma during the follow up period were included in the study. Patients underwent surgery at different levels: 3 patients for T10–T11 and 7 patients for T11–T12. Percutaneous endoscopic thoracic discectomy was performed following under‐vision foraminoplasty, which was based on lower pedicel‐ligament flavum tunnel detection. Patients who presented with symptomatic soft disc herniation of the thoracic spine and did not respond to conservative treatments were included. Patients with calcified disc herniation or concomitant ossification of the posterior longitudinal ligament were excluded. The surgery involves four steps: (i) facet joint reaching procedures; (ii) sliding the working sleeve caudally to attach the pedicel, rotating the scope to detect the lower border of the superior articular process, the pedicel, and the lower pedicel‐ligamentum flavum tunnel (PEFT) under vision, respectively; (iii) milling the superior articular process under vision; and (iv) finding and removing the disc protrusion after the posterior longitudinal ligament is resected. Patient outcomes were evaluated using vision analog scale scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores. The VAS scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores before and after the operation were compared by t‐test for statistical analysis. MRI, CT, and plain X‐rays were performed in of all the patients before and after surgery.ResultsThe patient was usually able to stand and walk approximately 2 h after the surgery. During the 12‐month follow‐up, all patients showed a significant improvement in pain. Postoperative thoracic MRI examination of all patients showed full decompression of the spinal cord and no residual pressure. Postoperative back pain and nerve root pain were significantly alleviated in all patients, and spinal cord function was significantly restored. The mean visual analog scale scores of patients postoperation were significantly better than those of patients preoperation (6.10 ± 1.37 vs 1.80 ± 0.79, P < 0.05). The mean ODI scores of patients postoperation were better than those of patients preoperation (13% ± 2.36% vs 55% ± 9.20%, P < 0.05). The mean JOA scores increased from 3.2 ± 0.75 to 9.3 ± 0.64. The JOA improvement rate was 79.6% ± 5.1%. There was 1 patient who had transient intercostal neuralgia.ConclusionFollowing pedicel‐ligament flavum tunnel outside‐in foraminoplasty protocols, T10–T12 discectomy is relatively safe when conducted under percutaneous endoscope.
MicroRNA profile in immune response of alveolar and cystic echinococcosis patients
Authors: Eroglu Fadime , Dokur Mehmet , Ulu Yüksel 
Published: January 2021

AbstractIt is known that miRNAs are effective in immune response in the diagnosis and treatment of many infectious diseases. However, the miRNAs profile is unknown in Alveolar and Cystic Echinococcosis which can be fatal if left untreated. The miRNAs profile that activates the T and B cells forming the immune system in Alveolar and Cystic Echinococcosis patients was investigated in this study. A total of 50 liver tissue samples were obtained from Alveolar and Cystic Echinococcosis patients in Kilis State Hospital Pathology Laboratory in southeast of Turkey. The circulating cell‐free miRNAs were evaluated by a quantitative real‐time polymerase chain reaction, statistically calculated within ΔΔCt values and fold changes were evaluated by Welch T test, in which P < .05 was considered to be significant. Twenty‐five microRNAs, including let‐7a‐5p, let‐7c, let‐7e‐5p, miR‐15b‐5p, miR16, miR‐17‐5p, miR‐23a‐5p, miR‐24‐3p, miR‐25‐3p, miR‐26a‐3p, miR‐26b‐3p, miR‐29b‐3p, miR‐29c‐3p, miR‐30a‐5p, miR‐30b‐5p, miR‐30c‐5p, miR‐30d‐5p, miR‐30e‐5p, miR‐98‐5p, miR‐101‐3p, miR‐106b‐5p, miR‐125b‐5p, miR‐142‐5p, miR‐222‐3p and miR‐223‐3p, were found as down‐regulated in Alveolar and Cystic Echinococcosis patients than control groups. Twelve miRNAs, including miR‐15a‐5p, miR‐21‐5p, miR‐27a‐3p, miR‐29a‐3p, miR‐146a‐5p, miR‐181a‐5p, miR‐181b‐5p, miR‐181d, miR‐181c‐5p, miR‐195‐5p, miR‐214‐3p and miR‐365‐3p, were found as up‐regulated in Alveolar and Cystic Echinococcosis patients than healthy person. It has been shown that T‐ and B‐cell activities are related in the progressive of both Alveolar and Cystic Echinococcosis in this study. The miRNA panel activated by T and B cells may be important for exploring the mechanisms underlying early development in Alveolar and Cystic Echinococcosis providing novel information that may be used to discover new therapeutics for these diseases.
Analyticity of rotational traveling gravity two‐layer waves
Authors: Chu Jifeng , Wang Ling‐Jun 
Published: January 2021

AbstractThe aim of this paper is to prove real analytic properties of all streamlines of two‐dimensional steady rotational gravity water waves in two‐layer flows. Provided that there are no stagnation points in the flow, we show that each streamline, including the free surface and the interface, is a real analytic curve if the height function is in , which corresponds to an arbitrarily bounded and measurable vorticity function. Our results generalize those for the situation of single layer flow, and improve the results in the work by Chu, Escher, and Wang [Analyticity of rotational travelling waves in two‐layer flows, submitted], where the analyticity is obtained for rotational two‐layer water waves when the height function is in corresponding to a Hölder continuous vorticity function.
What Guns Mean: Who Sees Guns as Important, Essential, and Empowering (and Why)?
Authors: Warner Tara D. , Ratcliff Shawn 
Published: January 2021

There is a fairly well‐established demographic profile of gun owners in the United States, yet much less is known about the meaning and importance individuals attach to guns, their right to own them, or the varying facets of gun owner identity. Unknown is if and/or how the attitudes, fears, concerns, and anxieties that influence gun ownership also shape the significance of guns in individuals’ lives. To that end, we examine three assessments of gun meaning: the importance of the right to own guns for one’s sense of freedom; the importance of being a gun owner to one’s personal identity; and the extent to which owners find guns emotionally and morally empowering (e.g., guns making one feel confident, important, in control). Using data from an original Mechanical Turk survey (n = 876), we show that diffuse political, social, and cultural anxieties shape gun meaning more so than do instrumental fears around crime and victimization.
Constitutive equation determination and dynamic numerical modelling of the compression deformation of concrete
Authors: Seven Semih Berk , Çankaya M. Alper , Uysal Çetin , Tasdemirci Alper , Saatçi Selçuk , Güden Mustafa 
Published: January 2021

AbstractThe dynamic compression deformation of an in‐house cast concrete (average aggregate size of 2–2.5 mm) was modelled using the finite element (FE), element‐free Galerkin (EFG) and smooth particle Galerkin (SPG) methods to determine their capabilities of capturing the dynamic deformation. The numerical results were validated with those of the experimental split Hopkinson pressure bar tests. Both EFG and FE methods overestimated the failure stress and strain values, while the SPG method underestimated the peak stress. SPG showed similar load capacity profile with the experiment. At initial stages of the loading, all methods present similar behaviour. Nonetheless, as the loading continues, the SPG method predicts closer agreement of deformation profile and force histories. The increase in strength at high strain rate was due to both the rate sensitivity and lateral inertia caused by the confinement effect. The inertia effect of the material especially is effective at lower strain values and the strain rate sensitivity of the concrete becomes significant at higher strain values.
Egyptian broomrape sucrose metabolism in response to different host plants
Authors: Farrokhi Zahra , Alizadeh Hassan , Alizadeh Houshang 
Published: January 2021

AbstractBroomrapes are important parasitic weeds in many vegetable crops in dry and warm regions of the world. The study of weed parasite physiology will increase knowledge of broomrape‐host interactions that may be applied to the development of improved parasitic plant control programmes. In this study, developmental patterns of activities of essential enzymes (sucrose synthase [SUS], mannose 6‐phosphate reductase [M6PR], cell wall invertase [CWI] and soluble acid invertase [SAI]) involved in Egyptian broomrape osmoregulation were investigated using three hosts (celery, tomato and cucumber). The earliest broomrape emergence occurred on cucumber; however, the total biomass of the parasite did not differ between cucumber and tomato. The reducing sugars content, gene expression and enzyme activity in the parasite significantly varied with the parasite organs and the hosts. Maximum SAI activity was observed in the apical part (AP) of the flowering shoot of parasite growing on cucumber. However, the peak of genes expression occurred in the same organ across the three hosts, for example SAI1 was expressed maximally in tubercle bearing the flowering shoot (Tub‐FS). The largest amount of reducing sugars was observed in the AP of the parasite grown on tomato. High M6PR activity in the parasite and its matching with M6PR transcriptional levels in three hosts are deemed promising for broomrape management through the deployment of the proteinaceous inhibitors or gene silencing constructs in host plants. Overall, the results indicated that differences in sugar metabolism of Egyptian broomrape grown on different hosts can potentially be exploited for effective management of this difficult‐to‐control parasite.
The hard problem: Mechanotransduction perpetuates the myofibroblast phenotype in scleroderma fibrosis
Authors: Leask Andrew 
Published: January 2021

AbstractThe effector cells ultimately responsible for fibrosis are myofibroblasts. In the fibrotic autoimmune connective tissue disease scleroderma, myofibroblasts are autonomously activated, and retain their phenotype upon culturing. Since the 1990s, researchers have exploited this fact to use scleroderma fibroblasts as a model system to uncover the fundamental mechanisms underlying myofibroblast persistence in fibrotic conditions. These studies have suggested that an autocrine transforming growth factor (TGF)beta signaling loop is insufficient to explain the persistent myofibroblast phenotype but instead support the hypothesis that fibrotic myofibroblasts possess an intrinsically activated pro‐adhesive signaling pathway, and that this contributes to the perpetuation of pathological fibrosis. This review focuses on these observations.
Containment and Arrest of Blade Shedding in Gas Turbine Engines Using Novel Dual-Ring Design
Authors: Roy P. A. , Meguid S. A. 
Published: January 2021

Abstract
In this paper, we examine the energy absorption and containment capabilities of a newly proposed dual-ring design accounting for interactions between a released blade and fully bladed fan disk using three-dimensional finite element analysis. The components of this dual-ring design are strategically selected to ensure high energy absorption and high impact resistance, thus leading to reduced damage of the disk and increased safety. Three containment ring designs are examined: (i) conventional single-ring design composed of one of titanium, aluminum, or Kevlar; (ii) a newly proposed aluminum-Kevlar dual-ring arrangement; and (iii) dual-ring arrangement with an interfacial gap between them to arrest and contain the released blade and ensure free passage of the trailing blades. The results of our numerical simulations indicate that although the single-ring design resists penetration and contains the released blade within the confines of the disk, it does not remove the released blade from the path of the trailing blades leading to severe damage to the fan disk. On the contrary, our new dual-ring design, which contains an interfacial gap, has potential to successfully arrest the released blade within the confines of the ring and out of the path of the trailing blades. This design can significantly reduce the impact damage to the fan disk and reduce kinetic energy of the released blade to near zero in less than half a rotation of the fan disk.
Investigation of Fuel and Load Flexibility in a Siemens Gas Turbine-600/700/800 Burner Under Atmospheric Pressure Conditions Using High-Speed Hydroxyl-PLIF and Hydroxyl Radical Chemiluminescence Imaging
Authors: Subash Arman Ahamed , Kim Haisol , Möller Sven-Inge , Richter Mattias , Brackmann Christian , Aldén Marcus , Lantz Andreas , Lindholm Annika , Larfeldt Jenny , Lörstad Daniel 
Published: January 2021

Abstract
Fuel and load flexibility have been increasingly important features of industrial gas turbines in order to meet the demand for increased utilization of renewable fuels and to provide a way to balance the grid fluctuations due to the unsteady supply of wind and solar power. Experimental investigations were performed using a standard third-generation dry low emission (DLE) burner under atmospheric pressure conditions to study the effect of central and pilot fuel addition, load variations, and hydrogen (H2) enrichment in a natural gas (NG) flame. High-speed kHz planar laser-induced fluorescence (PLIF) of OH radicals and imaging of OH chemiluminescence were employed to investigate the flame stabilization, flame turbulence interactions, and flame dynamics. Along with the optical measurements, combustion emissions were also recorded to observe the effect of changing operating conditions on NOX level. The burner is used in Siemens industrial gas turbines SGT-600, SGT-700, and SGT-800 with minor hardware differences and the study thus is a step to characterize fuel and load flexibility for these turbines. Without pilot and central fuel injections in the current burner configuration, the main flame is stabilized creating a central recirculation zone (CRZ). Addition of the pilot fuel strengthens the outer recirculation zone (ORZ) and moves the flame anchoring position slightly downstream, whereas the flame moves upstream without affecting the ORZ when central fuel injection is added. The flame was investigated utilizing H2/NG fuel mixtures where the H2 amount was changed from 0 to 100%. The results show that the characteristics of the flames are clearly affected by the addition of H2 and by the load variations. The flame becomes more compact, the anchoring position moves closer to the burner exit and the OH signal distribution becomes more distinct for H2 addition due to increased reaction rate, diffusivity, and laminar burning velocity. Changing the load from part to base, similar trends were observed in the flame behavior but in this case due to the higher heat release because of increased turbulence intensity.
Thermo-Structural Analysis of Steam Turbine Startup With and Without Integrated Prewarming System Using Hot Air
Authors: Łuczyński Piotr , Pehle Lukas , Wirsum Manfred , Mohr Wolfgang F. D. , Vogt Jan , Helbig Klaus 
Published: January 2021

Abstract
Motivated by the urgent need for flexibility and startup capability improvements of conventional power plants in addition to extending their life cycle, General Electric provides its customers with a product to prewarm steam turbines using hot air. In this paper, the transient thermal and structural analyses of a 19-stage intermediate pressure (IP) steam turbine in various startup operating modes are discussed in detail. The presented research is based on previous investigations and utilizes a hybrid finite element method (HFEM—numerical FEM and analytical) approach to efficiently determine the time-dependent temperature distribution in the components of the steam turbine. The simulation strategy of the HFEM model applies various analytical correlations to describe heat transfer in the turbine channel. These are developed by means of extensive unsteady multistage conjugate heat transfer (CHT) simulations for both startup turbine operation with steam and prewarming operation with hot air. Moreover, the complex numerical setup of the HFEM model also considers the thermal contact resistance (TCR) on the surfaces between vane and casing as well as blades and rotor. Prior to the analysis of other turbine startup operating modes, the typical startup turbine process is calculated and validated against an experimental data as a benchmark for subsequent analysis. In addition to heat transfer correlations, the simulation of a turbine startup from cold state uses an innovative analytic pressure model to allow for a consideration of condensation effects during first phase of startup procedure. Finally, the presented thermal investigation focuses on the comparison of transient temperature fields in the turbine for different startup scenarios after prewarming with hot air and provides the subsequent structural investigation with required boundary conditions. As a result, the values of the highest stress are numerically determined and compared to the values obtained by means of cold startup simulation. The final evaluation clearly displays the technical potential and the benefits of the prewarming concept.
Analysis of Timewise Compressor Fouling Phenomenon on a Multistage Test Compressor: Performance Losses and Particle Adhesion1
Authors: Vulpio Alessandro , Suman Alessio , Casari Nicola , Pinelli Michele , Kurz Rainer , Brun Klaus 
Published: January 2021

Abstract
The analysis of the performance losses of a multistage compressor concerning the air contaminant is not widespread in literature and, the mutual interactions of particle materials, air humidity, and compressor load are not well studied. The airborne micrometric particles that enter the compressor can deposit on the internal surfaces, causing the loss of performance of the machine. In this paper, several experimental tests have been carried out on a multistage compressor unit. A detailed analysis has been carried out considering soil and soot ingestion, as well as the air relative humidity (RH) (ranging from 50% RH to 80% RH) and compressor rotating velocity. Several combinations of particle diameter, material, and operating conditions have been considered. The amount of contaminant at the compressor outlet has been measured and the capture efficiency of the whole machine has been determined. Over the exposure time, the capture efficiency ranges from 0.2 to 0.6 according to the powder type and compressor inlet conditions. The capability of the compressor to collect particles changes over time as a function of the condition, even if several tested cases appear characterized by an almost constant capture efficiency trend. In addition, the performance degradation has been monitored over time and, with the reference of the particle concentration, the present experimental campaign covers about 500 operating hours of an actual installation. After a detailed evaluation of experimental uncertainty, the performance losses due to particle contamination have been assessed. The losses in the compressor performance have been estimated by means of the pressure ratio of the axial stages. The maximum degradation has been estimated equal to 0.53%/h for the compressor pressure ratio. Soot particles appear stickier, especially in the presence of higher humidity and represent the most detrimental operating conditions for the compressor unit.