bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Mechanical Properties of Chelyabinsk LL5 Chondrite Under Compression and Tension
Authors: Zaytsev Dmitry , Borodin Elijah N. , Dudorov A. E. , Panfilov P. 
Published: February 2021

AbstractThe mechanical properties of Chelyabinsk LL5 chondrite (Chelyabinsk meteorite) were studied by uniaxial compression and diametral compression/indirect tension test. Twenty cylindrical samples, 10 for compression and 10 for tension, with the diameter 3.3 mm and 1.65 mm in height have been prepared for testing. It was shown that the strength of the tested samples under compression almost 45 times greater than it is at tension: 372 ± 10 MPa and 8.2 ± 0.7 MPa, respectively. Fracture behaviour under compression and tension was similar and can be characterised as brittle. The obtained compression strength of the Chelyabinsk meteorite lies close to the maximal values of strength for many other chondrites, whereas its tensile strength magnitude resides in the bottom quarter of the range of similar measurements. It may be caused by the small sizes of the investigated samples together with a large number of tiny cracks between the grains in the Chelyabinsk chondrite. Our estimations have shown that if one assumes that the initial shape of the Chelyabinsk fireball was spherical or ellipsoidal, then its fragmentation stress is close to the experimental tensile strength and much lower than the compression strength. Hence, a stress state equivalent to one appearing at the indirect tension test could occur in the Chelyabinsk fireball during its fall in the Earth atmosphere.
Stability analysis of whirl flutter in rotor-nacelle systems with freeplay nonlinearity
Authors: Mair Christopher , Titurus Branislav , Rezgui Djamel 
Published: February 2021

AbstractTiltrotor aircraft are growing in prevalence due to the usefulness of their unique flight envelope. However, aeroelastic stability—particularly whirl flutter stability—is a major design influence that demands accurate prediction. Several nonlinearities that may be present in tiltrotor systems, such as freeplay, are often neglected for simplicity, either in the modelling or the stability analysis. However, the effects of such nonlinearities can be significant, sometimes even invalidating the stability predictions from linear analysis methods. Freeplay is a nonlinearity that may arise in tiltrotor nacelle rotation actuators due to the tension–compression loading cycles they undergo. This paper investigates the effect of a freeplay structural nonlinearity in the nacelle pitch degree of freedom. Two rotor-nacelle models of contrasting complexity are studied: one represents classical whirl flutter (propellers) and the other captures the main effects of tiltrotor aeroelasticity (proprotors). The manifestation of the freeplay in the systems’ dynamical behaviour is mapped out using Continuation and Bifurcation Methods, and consequently the change in the stability boundary is quantified. Furthermore, the effects on freeplay behaviour of (a) model complexity and (b) deadband edge sharpness are studied. Ultimately, the freeplay nonlinearity is shown to have a complex effect on the dynamics of both systems, even creating the possibility of whirl flutter in parameter ranges that linear analysis methods predict to be stable. While the size of this additional whirl flutter region is finite and bounded for the basic model, it is unbounded for the higher complexity model.
Ordering global governance complexes: The evolution of the governance complex for international civil aviation
Authors: Eilstrup-Sangiovanni Mette 
Published: February 2021

AbstractMany observers worry that growing numbers of international institutions with overlapping functions undermine governance effectiveness via duplication, inconsistency and conflict. Such pessimistic assessments may undervalue the mechanisms available to states and other political agents to reduce conflictual overlap and enhance inter-institutional synergy. Drawing on historical data I examine how states can mitigate conflict within Global Governance Complexes (GGCs) by dissolving or merging existing institutions or by re-configuring their mandates. I further explore how “order in complexity” can emerge through bottom-up processes of adaptation in lieu of state-led reform. My analysis supports three theoretical claims: (1) states frequently refashion governance complexes “top-down” in order to reduce conflictual overlap; (2) “top-down” restructuring and “bottom-up” adaptation present alternative mechanisms for ordering relations among component institutions of GGCs; (3) these twin mechanisms ensure that GGCs tend to (re)produce elements of order over time–albeit often temporarily. Rather than evolving towards ever-greater fragmentation and disorder, complex governance systems thus tend to fluctuate between greater or lesser integration and (dis)order.
Comparison of quantitative measurements between two different intravascular ultrasound catheters and consoles: in vitro and in vivo studies
Authors: Okura Hiroyuki , Watanabe Makoto , Miura Akihiro , Kurokawa Muneo , Ueda Tomoya , Soeda Tsunenari , Saito Yoshihiko 
Published: February 2021

AbstractPrevious studies suggested possible discordant quantitative measurements between different IVUS catheters and/or systems. The purpose of this study was to assess compatibility of two different IVUS catheters and consoles for quantitative measurements of coronary arteries. (1). In vitro study: IVUS imaging was performed in a concentric cylindrical phantom with 6 sections of known, cross-sectional diameter ranging from 3.0 to 8.0 mm. The lumen diameter (LD) and lumen cross-sectional area (LA) were measured and compared. To compare between 2 different IVUS consoles, IVUS images were obtained using a single IVUS catheter (catheter 1) connected to 2 different IVUS consoles (console 1 and 2). To compare between 2 different IVUS catheters, IVUS imaging was obtained using 2 different IVUS catheters (catheter 1 and 2) connected to a single IVUS console (console 2). (2). In vivo study: IVUS imaging was performed in 40 stented coronary arterial segments from 40 patients. The maximal stent diameter (Max SD), minimal stent diameter (minSD), and stent area (SA) were measured at both distal and proximal stent edges and compared between the two IVUS consoles (console 1 and 2) connected to a single IVUS catheter (catheter 1) (n = 20). IVUS imaging was also performed to compare between catheter 1 and 2 connected to IVUS console 2 (n = 20). Both in vitro and in vivo studies showed good correlation between the two IVUS consoles as well as two IVUS catheters. In conclusion, two IVUS catheters and consoles provide comparable IVUS measures both in vitro and in vivo.
Tribological interactions of 3D printed polyurethane and polyamide with water-responsive skin model
Authors: Kasar Ashish K. , Chan Ashton , Shamanaev Victor , Menezes Pradeep L. 
Published: February 2021

Abstract3D printing in the textile and fashion industry is a new emerging technology. Applications of 3D printing for designing clothes and other wearable accessories require tribological and biological understanding of 3D printing plastics against the complex human skin to mitigate skin-friction related ailments such as calluses and blisters. This study provides tribological insight in search of an optimal 3D printable material that has minimal friction against the skin. Two low friction 3D printable materials, thermoplastic polyurethane (TPU) and polyamide (TPA) were chosen and tribological testing was carried out against a water responsive skin model. The skin model was synthesized using a gelatine based model made with cotton and crosslinked with glutaraldehyde. Tribological testing of TPU/TPA against the skin model in dry and wet conditions were made. The higher coefficient of friction (COF) was observed in the wet condition compared to the dry condition. To overcome the higher friction, TPA/TPU-sodium polyacrylate composites were prepared by heat pressing that significantly reduced COF of TPU and TPA by ∼ 40% and 75%, respectively, in wet conditions.
Integrative emergence in contrast to separating modularity in plant biology: views on systems biology with information, signals and memory at scalar levels from molecules to the biosphere
Authors: Lüttge Ulrich 
Published: February 2021

AbstractModularity is reductionism and materialism, where modules are considered as building blocks per se. By contrast self-organization of modules in living organisms, like plants, generates the emergence of integrated systems with new properties not predicted by the properties of the modules. This can occur at the hierarchy of a series of scalar levels, where emergent systems become modules for emergence of new systems on the next higher scalar level akin to a hierarchy of networks from molecules, cells and individuals up to the levels of ecosystems, biomes and the entire biosphere or Gaia. The systems on these levels are holobiont-like systems, i.e., central organisms in interaction with all their associated organisms as a unit for selection in evolution. Systems biology, now a modern aspect of plant biology, has started with the advancement of whole-plant physiology in the early 1970s unraveling the roles of signaling for integration and cooperation of parts or modules in the performance of entire plants. Fixation of information in plant memory and emergence from such storage rules the timing of events of emergence. With the enthusiasm promoted by the creative self-organization of modules into the emergence of exciting new systems, biology diverts from the reductionism and materialism of bare modularity. Understanding emergence helps to advance on the rocky paths towards understanding the complexity of life.
Development of a roof bolter drilling control process to reduce the generation of respirable dust
Authors: Jiang Hua , Luo Yi 
Published: February 2021

AbstractThe drilling operation in the roof bolting process, especially in hard rock, generates excessive respirable coal and quartz dusts, which could expose the roof bolting operator to continued health risks. Previous research has shown that the amount of respirable dust produced is dependent on the main drilling parameters, specifically the drilling rotational and penetration rate. In this paper, a roof bolter drilling control process was proposed to reduce the generation of respirable dust. Based on the analysis of laboratory drilling test results, a rational drilling control process (adjusting rotational and penetration rates) to achieve the optimal drilling parameter for different rock types was proposed. In this process, the ratio between specific energy and rock uniaxial compressive strength was used as the index to determine the optimal operation point. The recommended drilling operation range for the rock type used in the experiment was provided, and the reduction in respirable dust generation was demonstrated. By following this control process, the drilling efficiency can be monitored in real time, so the system can stay in a relatively high-energy efficiency with less respirable dust production from the drilling source. This algorithm is targeted to be incorporated into the current roof bolter drilling control system for drilling automation so that a safe and productive drilling operation can be conducted in a healthy working environment.
Injectable Self-Healing Adhesive pH-Responsive Hydrogels Accelerate Gastric Hemostasis and Wound Healing
Authors: He Jiahui , Zhang Zixi , Yang Yutong , Ren Fenggang , Li Jipeng , Zhu Shaojun , Ma Feng , Wu Rongqian , Lv Yi , He Gang , Guo Baolin , Chu Dake 
Published: February 2021

AbstractEndoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are well-established therapeutics for gastrointestinal neoplasias, but complications after EMR/ESD, including bleeding and perforation, result in additional treatment morbidity and even threaten the lives of patients. Thus, designing biomaterials to treat gastric bleeding and wound healing after endoscopic treatment is highly desired and remains a challenge. Herein, a series of injectable pH-responsive self-healing adhesive hydrogels based on acryloyl-6-aminocaproic acid (AA) and AA-g-N-hydroxysuccinimide (AA-NHS) were developed, and their great potential as endoscopic sprayable bioadhesive materials to efficiently stop hemorrhage and promote the wound healing process was further demonstrated in a swine gastric hemorrhage/wound model. The hydrogels showed a suitable gelation time, an autonomous and efficient self-healing capacity, hemostatic properties, and good biocompatibility. With the introduction of AA-NHS as a micro-cross-linker, the hydrogels exhibited enhanced adhesive strength. A swine gastric hemorrhage in vivo model demonstrated that the hydrogels showed good hemostatic performance by stopping acute arterial bleeding and preventing delayed bleeding. A gastric wound model indicated that the hydrogels showed excellent treatment effects with significantly enhanced wound healing with type I collagen deposition, α-SMA expression, and blood vessel formation. These injectable self-healing adhesive hydrogels exhibited great potential to treat gastric wounds after endoscopic treatment.
Effect of microrelief and water-table on vegetation dynamics in silty loam saline soils of coastal areas
Authors: Mansouri Mohammad , Javadi Seyed Akbar , Jafari Mohammad , Arzani Hossein 
Published: February 2021

AbstractMicrorelief (MR) and water-table (WT) severely influence plant communities formation and development in silty loam saline soils of coastal areas. This research aimed to investigate the effect of MR and WT fluctuations on the dynamics of vegetation in coastal silty loam saline soils of southern Iran. Soil characteristics, vegetation structure and composition were investigated through the growing season, and obtained data were submitted to a canonical correspondence analysis. Based on the results, MR (min = 0.5 m and max = 1.0 m) and WT (max = 1 m) fluctuations significantly changed both structure and floristic composition through change in soil characteristics (Sig. < 0.05). Factors of soil moisture content, SAR and Na severely changed under MR and WT fluctuations and received new eigenvalues through the year. Our results demonstrated that a minimum change in MR and/or WT influence soil properties and vegetation structure and composition in silty loam saline soils of coastal areas.
Power and energy system oscillation damping using multi-verse optimization
Authors: Devarapalli Ramesh , Bhattacharyya Biplab 
Published: February 2021

AbstractPower system oscillations are the primary threat to the stability of a modern power system which is interconnected and operates near to their transient and steady-state stability limits. Power system stabilizer (PSS) is the traditional controller to damp such oscillations, and flexible AC transmission system (FACTS) devices are advised for the improved damping performance. This paper suggests a technique for controller parameters tuning of PSS and a shunt connected FACTS device to be operated in coordination. A static synchronous compensator (STATCOM) connected in a two-machine system is considered as a test power system for the system studies. A recent meta-heuristic algorithm, Multi-Verse optimizer (MVO) has been suggested and compared with the other state-of-the-art algorithms. Improvement in system damping has been achieved by minimizing the oscillating nature of the system states by framing the objective function as a function of damping ratio and location of poles of the system. The Phillips-Heffron model of the test system has been designed by considering the system dynamics. The coordinated system behavior under the perturbation in system parameters has been observed satisfactory with the tuned controller parameters obtained from the suggested algorithm.
Two-phase flow of dusty fluid with suspended hybrid nanoparticles over a stretching cylinder with modified Fourier heat flux
Authors: Varun Kumar R. S. , Punith Gowda R. J. , Naveen Kumar R. , Radhika M. , Prasannakumara B. C. 
Published: February 2021

AbstractThe current paper explores the influence of hybrid nanoparticles on the dusty liquid flow through a stretching cylinder by employing the modified Fourier heat flux law. Two phase model is implemented in the present research to characterise the fluid flow. Molybdenum disulphide and silver are used as nanoparticles suspended in base fluid water. The equations which represent the described flow are changed into a set of ordinary differential equations by opting appropriate similarity variables. The reduced dimensionless nonlinear ODEs are numerically solved out by using Runge–Kutta–Fehlberg fourth fifth order inclusive of shooting approach. The impact of several dimensionless parameters over velocity and thermal gradients are deliberated by using graphs. Graphical illustrations for skin friction are also executed. Result outcome reveals that, rise in values of mass concentration of particle declines the velocity and thermal gradient of both dust and fluid phases and cumulative in curvature parameter upsurges the velocity and thermal gradient within the boundary. Further, the heightening of thermal relaxation parameter enhances the thermal profile of both fluid and dust phases.
A Semi-supervised Approach for Sentiment Analysis of Arab(ic+izi) Messages: Application to the Algerian Dialect
Authors: Guellil Imane , Adeel Ahsan , Azouaou Faical , Benali Fodil , Hachani Ala-Eddine , Dashtipour Kia , Gogate Mandar , Ieracitano Cosimo , Kashani Reza , Hussain Amir 
Published: February 2021

AbstractIn this paper, we propose a semi-supervised approach for sentiment analysis of Arabic and its dialects. This approach is based on a sentiment corpus, constructed automatically and reviewed manually by Algerian dialect native speakers. This approach consists of constructing and applying a set of deep learning algorithms to classify the sentiment of Arabic messages as positive or negative. It was applied on Facebook messages written in Modern Standard Arabic (MSA) as well as in Algerian dialect (DALG, which is a low resourced-dialect, spoken by more than 40 million people) with both scripts Arabic and Arabizi. To handle Arabizi, we consider both options: transliteration (largely used in the research literature for handling Arabizi) and translation (never used in the research literature for handling Arabizi). For highlighting the effectiveness of a semi-supervised approach, we carried out different experiments using both corpora for the training (i.e. the corpus constructed automatically and the one that was reviewed manually). The experiments were done on many test corpora dedicated to MSA/DALG, which were proposed and evaluated in the research literature. Both classifiers are used, shallow and deep learning classifiers such as Random Forest (RF), Logistic Regression(LR) Convolutional Neural Network (CNN) and Long short-term memory (LSTM). These classifiers are combined with word embedding models such as Word2vec and fastText that were used for sentiment classification. Experimental results (F1 score up to 95% for intrinsic experiments and up to 89% for extrinsic experiments) showed that the proposed system outperforms the existing state-of-the-art methodologies (the best improvement is up to 25%).
Analysis of risk factors for lateral lymph node metastasis in papillary thyroid carcinoma: A retrospective cohort study
Authors: Liu Qiang , Pang Wen‐ting , Dong Yan‐bo , Wang Zhen‐xiao , Yu Ming‐hang , Huang Xue‐feng , Liu Liang‐fa 
Published: February 2021

AbstractObjectiveTo investigate the risk factors for lateral lymph node metastasis (LLNM) in papillary thyroid carcinoma (PTC).MethodsA retrospective analysis of 209 patients with PTC who underwent primary surgery at the Beijing Friendship Hospital affiliated with Capital Medical University from November 2014 to November 2018 was performed. The patients were divided into the LLNM group and the non‐LLNM group. The clinical and pathological characteristics of the patients were analysed. The risk factors for LLNM were analysed by univariate and multivariate analyses.ResultsThe incidence of LLNM was 13.4% in PTC patients. Univariate analysis showed that the maximum diameter of the primary tumour > 2 cm (P < 0.001), bilateral primary tumour (P = 0.020), extrathyroidal extension (ETE) (P < 0.001), central lymph node metastasis (CLNM) (P < 0.001), and CLNM number ≥ 5 (P < 0.001) were significantly associated with LLNM. Multivariate logistic regression analysis showed that the maximum diameter of the primary tumour > 2 cm, ETE, and CLNM were independent risk factors for LLNM (OR values were 3.880, 5.202, and 4.474, respectively). There were 6 patients with skip lateral cervical lymph node metastasis, accounting for 21% of all LLNM patients.ConclusionThis study revealed several independent risk factors for predicting LLNM in PTC patients, such as the maximum diameter of the primary tumour > 2 cm, ETE and CLNM. Lateral neck dissection may be recommended in PTC patients with those risk factors. Paying attention to the occurrence of skip lateral cervical lymph node metastasis during the clinical diagnosis and treatment processes is necessary.
Polymorphisms in CXCR3 ligands predict early CXCL9 recovery and severe chronic GVHD
Authors: Dai Hao , Rachakonda Sivaramakrishna P. , Penack Olaf , Blau Igor W. , Blau Olga , Radujkovic Aleksandar , Müller-Tidow Carsten , Dreger Peter , Kumar Rajiv , Luft Thomas 
Published: February 2021

AbstractChronic graft-versus-host disease (cGVHD) is a major cause of mortality and morbidity after allogeneic stem cell transplantation (alloSCT). The individual risk of severe cGVHD remains difficult to predict and may involve CXCR3 ligands. This study investigated the role of single-nucleotide polymorphisms (SNPs) of CXCL4, CXCL9, CXCL10, and CXCL11, and their day +28 serum levels, in cGVHD pathogenesis. Eighteen CXCR3 and CXCL4, CXCL9–11 SNPs as well as peri-transplant CXCL9–11 serum levels were analyzed in 688 patients without (training cohort;n = 287) or with statin-based endothelial protection cohort (n = 401). Clinical outcomes were correlated to serum levels and SNP status. Significant polymorphisms were further analyzed by luciferase reporter assays. Findings were validated in an independent cohort (n = 202). A combined genetic risk comprising four CXCR3 ligand SNPs was significantly associated with increased risk of severe cGVHD in both training cohort (hazard ratio (HR) 2.48, 95% confidence interval (CI) 1.33–4.64,P = 0.004) and validation cohort (HR 2.95, 95% CI 1.56–5.58,P = 0.001). In reporter assays, significantly reduced suppressive effects of calcineurin inhibitors in constructs with variant alleles of rs884304 (P < 0.001) and rs884004 (P < 0.001) were observed. CXCL9 serum levels at day +28 after alloSCT correlated with both genetic risk and risk of severe cGVHD (HR 1.38, 95% CI 1.10–1.73,P = 0.006). This study identifies patients with high genetic risk to develop severe cGVHD.