bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypoxia stimulates collagen hydroxylation in gingival fibroblasts and periodontal ligament cells
Authors: Morimoto Chiaki , Takedachi Masahide , Kawasaki Kohsuke , Shimomura Junpei , Murata Mari , Hirai Asae , Kawakami Kazuma , Sawada Keigo , Iwayama Tomoaki , Murakami Shinya 
Published: March 2021

AbstractBackgroundCellular responses to hypoxia regulate various biological events, including angiogenesis and extracellular matrix metabolism. Collagen is a major component of the extracellular matrix in periodontal tissues and its coordinated production is essential for tissue homeostasis. In this study, we investigated the effects of hypoxia on collagen production in human gingival fibroblasts (HGFs) and human periodontal ligament cells (HPDLs).MethodsHGFs and HPDLs were cultured under either normoxic (20% O2) or hypoxic (1% O2) conditions. Nuclear expression of hypoxia‐inducible factor‐1α (HIF‐1α) was determined by western blotting. Peri‐cellular expression of type I collagen was examined by immunocytochemistry analysis. Synthesis of type I collagen was evaluated by measuring the concentration of procollagen type I C‐peptide (PIP) in culture supernatant using enzyme‐linked immunosorbent assay. Expression of collagen hydroxylase enzymes prolyl 4‐hydroxylase alpha polypeptide 1 (P4HA1) and 2‐oxoglutarate 5‐dioxygenase 2 (PLOD2) was determined by RT‐qPCR and western blotting. The roles of these enzymes were analyzed using siRNA transfection.ResultsCultivation under hypoxic conditions stimulated type I collagen production via HIF‐1α in both cell types. Interestingly, hypoxic conditions did not affect collagen 1a1 or 1a2 gene expression but upregulated that of P4HA1 and PLOD2. Additionally, suppressing P4HA1 significantly decreased the levels of hypoxia‐induced procollagen type I C‐peptide, a product of stable triple helical collagen, in the supernatant. In contrast, PLOD2 suppression decreased cross‐linked collagen expression in the pericellular region.ConclusionOur results suggest that hypoxia activates collagen synthesis in HGFs and HPDLs by upregulating hydroxylases P4HA1 and PLOD2 in an HIF‐1α‐dependent manner.
Topological Characteristics of Chain Molecules with Branching and Molar‐Mass Distributions
Authors: Nitta Koh‐hei 
Published: March 2021

AbstractA graph‐theoretical method is presented for characterizing the statistical and dynamic properties of randomly and fixed‐branched chains that exhibit molecular weight distribution. The Wiener index, which is a topological index reflecting tree‐shaped structures, of any branched chain estimated from its random‐flight model (molecular graph) enables to express the radius of gyration and dynamic relaxation times of various chains with branching and molar‐mass distributions. A homologous series of branched chains with random branching points can be obtained by comparing their Wiener indices with those of their corresponding primitive chains (where the subchains between adjacent branch or end points are reduced to single bonds). Moreover, the analogical growth of a fixed‐branched structure during polymerization can be quantitatively analyzed using analogous functions, which are also determined by comparing the statistics and dynamic properties of branched polymers and their primitive chains.
Recent development in bacterial cellulose production and synthesis of cellulose based conductive polymer nanocomposites
Authors: Poddar Maneesh Kumar , Dikshit Pritam Kumar 
Published: March 2021

AbstractCompared to plant‐based cellulosic biopolymers, bacterial cellulose (BC) produced from microbial sources demonstrates several unique properties. BC nanocomposites synthesized with the addition of nanofillers with distinct properties have further tailored the BC structure with improved physical and chemical properties. BC nanocomposites with the addition of electrically conductive filler materials, namely, conductive polymers, metallic or carbonaceous nanofillers have advanced the nanocomposites applications and their utilization in the fabrication of various modern electrical and electronic appliances such as biosensors, flexible electronics, electromagnetic interference (EMI) shielding and energy storage. The present review is focused to provide a complete overview of BC production and electrically conductive‐based‐BC nanocomposites at a single platform. Various methodologies used in BC production with varying microbial strains and substrate types used in the fermentation, surface functionalization of BC, and its purification are discussed in detail. Subsequently, the review explains the bacterial cellulose‐based electrical conductive nanocomposites combined with different types of nanofillers such as conductive polymers, metal oxides, and carbon‐based nanofillers for their application in modern electronic devices. The challenges faced during nanocomposites synthesis and methods to improve its electrical conductivity with possible futuristic solutions are also briefly discussed.
Measurement of total liver blood flow in intact anesthetized rats using ultrasound imaging
Authors: Gibson Christopher R. , Gleason Alexa , Messina Eric 
Published: March 2021

AbstractThis short report describes the measurement of total liver blood flow in commonly used laboratory rats using the relatively non‐invasive approach of ultrasound imaging. A total of 29 rats (n = 26 Wistar‐Han, n = 3 Sprague–Dawley) were imaged and both male and female rats were included. The mean (SD) total liver blood flow of all animals combined was 33.3 ± 7.8 mL/min, or 104.3 ± 17.1 mL/min/kg when normalized to observed body weight at the time of imaging. There was a trend for higher unnormalized total liver blood flow as body weight increased and the female rats had, in general, the lowest body weight and total liver blood flow of the animals studied. There were no major differences in total liver blood flow between the small number of Sprague–Dawley rats used in the study and the larger Wistar‐Han group. Further research would be needed to accurately characterize any subtle differences in body weight between rats of different strains, sexes, and body weight.
Co‐Production of Bio‐Ethanol and Bio‐Oil from Different Species of Macroalgae
Authors: Li Chen , Liu Zhongxin , Ning Dandan , Pan Jingwen , Li Jinhua 
Published: March 2021

AbstractThis paper proposed a methodology to realize the co‐production of bio‐ethanol and bio‐oil from macroalgae. Bio‐ethanol were obtained from three different species of macroalgae (Enteromorpha prolifera, Undaria pinnatifida and Gelidium amansii) by hydrolysis and fermentation. And then the residues after hydrolysis were converted into bio‐oil with high heating value via deoxy‐liquefaction. The yield of reducing sugar and bio‐ethanol from three macroalgae were calculated. The red algae (Gelidium amansii) produced the reducing sugar with largest yield of 320±4.1 mg/g and ethanol with a maximum content of 9.09±0.07 g/L. Besides, the properties and components of the liquid oils have been analyzed and compared with each other. The lower oxygen content (4.47 %, 4.98 % and 4.02 %) and higher heating value (45.06, 44.53 and 45.12 MJ/kg) of the liquid oils were detected respectively. The results indicated that macroalgae had a great potential for co‐production of bio‐ethanol and high‐quality bio‐oil.
Photochemical Insights on Intramolecular Dye‐Sensitized Free‐Radical Processes with a Quinoline Antenna
Authors: Akari Aviya S. , Hodgson Gregory K. , Golian Karol P. , Impellizzeri Stefania 
Published: March 2021

AbstractOrganic fluorophores containing paramagnetic nitroxides covalently tethered to the chromophoric core show a dramatic reduction in fluorescence due to intramolecular quenching of their excited states. Nonetheless, trapping of hydrogen atoms or carbon‐centered radicals by the nitroxide suppresses the quenching pathway and restores the fluorescence, an effect that can be used to monitor radical scavenging processes. Herein, we synthesized a prefluorescent radical probe in which a 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) moiety was chemically coupled to a quinoline chromophore, which can directly sensitize TEMPO via energy transfer following low‐intensity ultraviolet illumination. In this design, the quinoline dye effectively acts as molecular ‘antenna’ to promote the reactivity of TEMPO toward H abstraction to form the corresponding N‐hydroxylamine. The excited TEMPO can also abstract a hydrogen from a polymeric matrix, enabling the photochemical modification of the polymer with concomitant fluorescence activation and patterning. In addition, the patterning process can be thermally reverted (‘erased’) by heating the film above the glass transition temperature of the polymer.
Economic lessons for COVID‐19 pandemic policies
Authors: Viscusi W. Kip 
Published: March 2021

AbstractThe COVID‐19 pandemic poses novel health issues. However, the benefits and costs of the pandemic and policies to address it have a familiar economic structure. Chief among the health‐related benefits are the monetized values of the U.S. mortality costs of $3.9 trillion in 2020. The combined U.S. mortality and morbidity costs are $5.5–5.9 trillion. Global mortality costs in 2020 total $10.1 trillion. The skewed age distribution of COVID‐19 illnesses has stimulated increased advocacy of downward adjustments in the value of a statistical life (VSL) for older people. This article examines the role of age for policy analysis generally and for the rationing of scarce medical treatments, such as ventilators. Mortality risk reduction benefits should be based on the reduced probability of death multiplied by the pertinent VSL. Effective communication of risks to foster precautions hinges on the credibility of the information source, which public officials have jeopardized. Efficient control of risks imposes limits on personal freedoms to foster health improvements.
Model for estimating the flexural performance of concrete reinforced with hooked end steel fibers using three‐point bending tests
Authors: Carrillo Julian , Vargas Juan D. , Alcocer Sergio M. 
Published: March 2021

AbstractThe behavior of fiber reinforced concrete (FRC) depends on the characteristics of both the concrete matrix and fibers. Previous studies have concluded that the number of hooked ends increases the contribution of steel fibers to the tensile performance of concrete. ACI 318 code, MC10 fib code and RILEM TC 162‐TDF standard permit the use of steel fiber reinforced concrete (SFRC) for example, the minimum shear reinforcement made of deformed steel bars in flexure‐controlled elements. Other investigations have demonstrated the suitable performance of SFRC in shear‐controlled members and for seismic rehabilitation applications. It has become apparent that the adequate use of SFRC depends on the knowledge and prediction capabilities of its tensile performance. The results of three‐point bending tests on SFRC beams using the test procedure established by the European standard EN‐14651 are presented and discussed herein. Tests were executed with 20 standardized beams made of concrete with a nominal compressive strength of 24 MPa and hooked end steel fibers with an aspect ratio of 65 were applied. Variables were the fiber dosage (0, 20, 40, 60 kg/m3) and the number of fiber hooked ends (1, 1.5, and 2). A numerical model aimed at estimating the residual flexural tensile strength of the SFRC is developed. The proposed model was calibrated using a database of 256 tests, 20 from this study and the remaining 236 from 15 other studies.
Numerical study on mixed convective flow of water‐based magnetite nanofluid through a wavy channel containing porous blocks under the effect of an oscillating magnetic field
Authors: Job Victor M. , Gunakala Sreedhara Rao 
Published: March 2021

AbstractIn this paper, the convective flow of magnetite (Fe3O4)‐water nanofluid through a wavy channel containing porous blocks in the presence of a non‐uniform oscillating magnetic field with magnetohydrodynamic (MHD) and ferrohydrodynamic (FHD) effects is considered. This magnetic field is produced by two current‐carrying wires, which are placed at fixed positions on the outside of the channel. In the present study, we use a two‐phase model that considers the effects of thermophoresis and Brownian motion on the concentration of nanoparticles within the fluid. The associated system of partial differential equations is solved using the mixed finite element method with Taylor‐Hood elements and the effects of time t, Strouhal number , Hartmann number , magnetic number , solid volume fraction ϕ0, nanoparticle diameter on the fluid flow, heat transfer, concentration distribution and pressure drop within the channel are investigated.
An analytical toolkit for the S-matrix bootstrap
Authors: Correia Miguel , Sever Amit , Zhiboedov Alexander 
Published: March 2021

Abstract
We revisit analytical methods for constraining the nonperturbative S-matrix of unitary, relativistic, gapped theories in d≥ 3 spacetime dimensions. We assume extended analyticity of the two-to-two scattering amplitude and use it together with elastic unitarity to develop two natural expansions of the amplitude. One is the threshold (non-relativistic) expansion and the other is the large spin expansion. The two are related by the Froissart-Gribov inversion formula. When combined with crossing and a local bound on the discontinuity of the amplitude, this allows us to constrain scattering at finite energy and spin in terms of the low-energy parameters measured in the experiment. Finally, we discuss the modern numerical approach to the S-matrix bootstrap and how it can be improved based on the results of our analysis.
Probing the top-Higgs sector with composite Higgs models at present and future hadron colliders
Authors: Bautista Carlos , de Lima Leonardo , D’Elia Matheus Ricardo , Pontón Eduardo , Fernandes do Prado Leônidas A. , Savoy-Navarro Aurore 
Published: March 2021

Abstract
We study the production of $$ t\overline{t}h $$
t

t
¯

h
and $$ t\overline{t} hh $$
t

t
¯

hh
at hadron colliders, in the minimal Composite Higgs Models, based on the coset SO(5)/SO(4). We explore the fermionic representations 5 and 14. A detailed phenomenological analysis is performed, covering the energy range of the LHC and its High Luminosity upgrade, as well as that of a future 100 TeV hadron collider. Both resonant and non-resonant production are considered, stressing the interplay and complementary interest of these channels with each other and double Higgs production. We provide sets of representative points with detailed experimental outcomes in terms of modification of the cross sections as well as resonance masses and branching ratios. For non-resonant production, we gauge the relative importance of Yukawa, Higgs trilinear, and contact $$ t\overline{t} hh $$
t

t
¯

hh
vertices to these processes, and consider the prospect for distinguishing the fermion representations from each other and from the Standard Model. In the production of top partners, we find that the three-body decay channel W+W–t becomes significant in certain regions of parameter space having a degenerate spectrum, and is further enhanced by increasing the top partner’s mass. This motivates both higher energy machines as well as the need to go beyond the current analysis performed for the searches for these resonances.
Propagation and interaction of weakly nonlinear plane waves in transversely isotropic elastic materials
Authors: Domański W. , Jemioło S. , Franus A. 
Published: March 2021

AbstractThe paper presents a study of the propagation and interaction of weakly nonlinear plane waves in isotropic and transversely isotropic media. It begins with a definition of stored energy functions of considered hyperelastic models. The equation of elastodynamics as well as the first-order quasilinear hyperbolic system for plane waves are provided. The eigensystem for this system is determined to study three-wave interaction coefficients. The main part of the paper concerns a discussion of these coefficients. Applying the weakly nonlinear asymptotics method, it is shown that in the case of transverse isotropy the inviscid Burgers’ equation describes an evolution of a single quasi-shear wave. The result contradicts the case of isotropy, where the equation with quadratic nonlinearity cannot describe any shear wave propagation. The paper ends with an example of numerical solutions for the obtained evolution equation.
Investigating Total Collisions of the Newtonian N-Body Problem on Shape Space
Authors: Reichert Paula 
Published: March 2021

AbstractWe analyze the points of total collision of the Newtonian gravitational system on shape space (the relational configuration space of the system). While the Newtonian equations of motion, formulated with respect to absolute space and time, are singular at the point of total collision due to the singularity of the Newton potential at that point, this need not be the case on shape space where absolute scale doesn’t exist. We investigate whether, adopting a relational description of the system, the shape degrees of freedom, which are merely angles and their conjugate momenta, can be evolved through the points of total collision. Unfortunately, this is not the case. Even without scale, the equations of motion are singular at the points of total collision (and only there). This follows from the special behavior of the shape momenta. While this behavior induces the singularity, it at the same time provides a purely shape-dynamical description of total collisions. By help of this, we are able to discern total-collision solutions from non-collision solutions on shape space, that is, without reference to (external) scale. We can further use the shape-dynamical description to show that total-collision solutions form a set of measure zero among all solutions.
Appearance of Thermal Time
Authors: Tanaka Shigenori 
Published: March 2021

AbstractIn this paper a viewpoint that time is an informational and thermal entity is presented. We consider a model for a simple relaxation process for which a relationship among event, time and temperature is mathematically formulated. It is then explicitly illustrated that temperature and time are statistically inferred through measurement of events. The probability distribution of the events thus provides an intrinsic correlation between temperature and time, which can relevantly be expressed in terms of the Fisher information metric. The two-dimensional differential geometry of temperature and time then leads us to a finding of a simple equation for the scalar curvature, $$R = -1$$

R
=
-
1

, in this case of relaxation process. This basic equation, in turn, may be regarded as characterizing a nonequilibrium dynamical process and having a solution given by the Fisher information metric. The time can then be interpreted so as to appear in a thermal way.
Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020)
Authors: Falasco Elisa , Ector Luc , Wetzel Carlos E. , Badino Guido , Bona Francesca 
Published: March 2021

AbstractOver the last years, issues concerning diatom teratological forms and environmental stress have received growing interest within the scientific community. Publications on this topic dated back to 1890 and were summarized in a review published in 2009 by the journalHydrobiologia, accounting for high citation rates (i.e. 117 citations Scopus and 232 citations Google Scholar, October 2020). This wide interest stimulates the authors to further unravel teratological forms significance in the light of the most recent publications (2010–2020). Diatom teratological forms are one of the best individual-level biomarkers since they provide a rapid response to several environmental stressors, including new emerging pollutants. The mechanisms involved in teratological valve likely involve both cytoskeleton and silicon metabolic pathway impairments. However, teratologies do not seem to weaken the reproduction capacity and viability of the affected individuals. We recognized eight types of teratologies as involving different parts of the valve, depending on genus. In order to summarize the information obtained by several years of research, we suggest a four-step procedure aimed at providing a theoretical pathway that researchers should follow to better explain results obtained in next-future studies and representing a starting point for the development of an environmental index based on teratological forms.
The European coal curse
Authors: Esposito Elena , Abramson Scott F. 
Published: March 2021

AbstractIn this paper we examine the impact of natural resource wealth by focusing on historical coal-mining across European regions. As an exogenous source of variation in coal extraction activities, we rely on the presence of coal-deposits located on the earth’s surface, which historically facilitated the discovery and extraction of coal. Our results show that former coal-mining regions are substantially poorer, with (at least) 10% smaller per-capita GDP than comparable regions in the same country that did not mine coal. We provide evidence that much of this lag is explained by lower levels of human capital accumulation and that this human-capital effect is concentrated in men. Finally, we provide suggestive evidence that the persistently lower levels of human capital in coal mining regions that we document result from the crystallization of negative attitudes towards education and lower future orientations in these regions.
Perception of Gamblers: A Systematic Review
Authors: Wöhr Andrea , Wuketich Marius 
Published: March 2021

AbstractIt is generally assumed that gamblers, and particularly people with gambling problems (PG), are affected by negative perception and stigmatisation. However, a systematic review of empirical studies investigating the perception of gamblers has not yet been carried out. This article therefore summarises empirical evidence on the perception of gamblers and provides directions for future research. A systematic literature review based on the relevant guidelines was carried out searching three databases. The databases Scopus, PubMed and BASE were used to cover social scientific knowledge, medical-psychological knowledge and grey literature. A total of 48 studies from 37 literature references was found. The perspective in these studies varies: Several studies focus on the perception of gamblers by the general population, by subpopulations (e. g. students or social workers), or by gamblers on themselves. The perspective on recreational gamblers is hardly an issue. A strong focus on persons with gambling problems is symptomatic of the gambling discourse. The analysis of the studies shows that gambling problems are thought to be rather concealable, whereas the negative effects on the concerned persons‘ lives are rated to be quite substantial. PG are described as “irresponsible” and “greedy” while they perceive themselves as “stupid” or “weak”. Only few examples of open discrimination are mentioned. Several studies however put emphasis on the stereotypical way in which PG are portrayed in the media, thus contributing to stigmatisation. Knowledge gaps include insights from longitudinal studies, the influence of respondents‘ age, culture and sex on their views, the relevance of the type of gambling a person is addicted to, and others. Further studies in these fields are needed.