bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromagnetic properties of a composite medium comprising chains of tunnel-coupled carbon nanotubes
Authors: Melnikau Aliaksandr V. , Shuba Mikhail V.
Published: August 2021

When creating a model of a composite medium based on carbon nanotubes in the gigahertz and subterahertz ranges, it is necessary to take into account the tunnel coupling between nanoparticles. To simplify the consideration, we present a model of a composite medium consisting of the same randomly oriented linear chains of parallel single walled metallic carbon nanotubes connected by tunnel contacts. The problem of scattering of electromagnetic radiation by the chains was solved through the application of the integral equation technique of classical electrodynamics and the Landauer – Buttiker formalism for quantum transport. It is shown that electron tunnelling between the nanotubes leads to the electromagnetic size effects in chains of finite length. In this case, in the gigahertz frequency range, there is a regime in which the comparable in magnitude real and imaginary parts of the effective permittivity of the composite medium decrease with increasing frequency that is often observed in experiments. It has been found that size effects can manifest themselves within small sections of the chain limited by contacts of low conductivity. The obtained results provide an understanding of the physical mechanisms responsible for the frequency dispersion of the permittivity of composite materials based on carbon nanotubes.
Adiabatic Brownian motor with a stepwise potential perturbed by a dichotomous harmonic sygnal
Authors: Shapochkina Irina V. , Savina Nastassia D. , Zaytseva Elena M. , Rozenbaum Viktor M. , Ikim Maria I. , Bugaev Aleksander S.
Published: August 2021

We obtained an analytical expression for the average motion velocity of an adiabatic Brownian motor (ratchet), which operates due to small dichotomous spatially harmonic fluctuations of a stepwise potential. The symmetry properties of the average velocity as a functional of the stationary and fluctuating components of the nanoparticle potential energy are revealed, and the ranges of values of the system parameters that ensure the rightward and leftward motion of the motor are determined. We showed that the average motor velocity is a non-monotonic function of the stepwise potential height. For a singular (infinitely high and narrow) potential barrier, the average velocity depends non-monotonically on the «power» of this barrier (the barrier width multiplied by the exponent of the ratio of the barrier height to the thermal energy). The article continues the further development of theoretical methods of symmetry analysis by applying the general approaches proposed by the authors to specific motor systems.
The spatial density distribution of the ion flux in the laser-plasma source for deposition of nanocoating on substrates of increased size
Authors: Goncharov Victor K. , Puzyrev Michail V. , Stupakevich Valery Yu. , Shulhan Nikita I.
Published: August 2021

The present work is devoted to the experimental determination of the uniformity of the ion flux density on a substrate with an increased size (~200 cm2 ) in order to form nanostructures by the laser-plasma method. The system for deposition of nanostructures consists of an erosion laser torch of the target material and a substrate located in a vacuum chamber. For smooth adjustment of the parameters of the deposited particles on the substrate, a grid is located between the laser target and the substrate, on which a negative potential is applied relative to the laser target. As a result, a particle stream is formed after the grid, consisting mainly of ions, whose energy can be reliably and smoothly controlled by applying a positive potential to the grid in relation to the substrate. Experiments have shown that the uniformity of the density of ion fluxes on a substrate of increased size (~200 cm2 ) in a laser-plasma source for nanocoating can be increased by applying an accelerating potential to the substrate in relation to the grid. The minimum difference between the ion flux density in the center of the target and at its edge can be reduced to ~5 %. As a result, it is technologically possible to clean the surface of the substrate with ions of the laser target material (secondary emission), create a pseudodiffusion layer of the target material in the near-surface region of the substrate, and apply the laser target material to the substrate. At the same time, all these operations can be performed sequentially without depressurising the vacuum chamber. This allows obtaining coating with good adhesion on substrates of increased size.
Optical properties of CdTe thin film obtained by high-frequency magnetron sputtering method
Authors: Kashuba Andrei I. , Andriyevsky Bogdan V. , Ilchuk Hrigorii A. , Piasecki Mikhal , Semkiv Igor’ V. , Petrus Roman Yu.
Published: August 2021

Cadmium telluride (CdTe) thin films relate to AII BVI compounds and show semiconductor behaviour. They present an important research field because of their wide application in various optoelectronic devices. CdTe-based solar cells attract attention since CdTe is characterised by the direct energy bandgap Eg and high absorbance, which makes it an excellent light-absorbing layer of solar cells. Material evaporation in vacuum by using the high-frequency magnetron sputtering method is one of the most advantageous methods for obtaining uniform films. The present work is dedicated to the investigation of the optical properties of CdTe thin film, which is produced on quarts substrate by the high-frequency magnetro sputtering method. The optical transmission, reflectivity, and μ-Raman spectra of the CdTe thin film have been determined. Linearity of the spectral dependence of the coefficient of optical absorption α of CdTe thin film in the coordinates (αhν)2  vs hν indicates for the direct character of optical transitions corresponding to the long-wavelength edge of fundamental absorption. The optical bandgap of the studied CdTe thin film is found to be Eg = 1.53 eV. The peaks of the experimental m-Raman spectra at 121; 139; 142; 167 and 331 cm–1 are attributed to the phonons in crystalline CdTe and Te.
On the limit of the accuracy of timе stamp at the detection of annihilation γ-quanta with a scintillation detector
Authors: Korzhik Mikhail V.
Published: August 2021

An influence of the various relaxation processes of the electronic excitations causing the scintillation in the crystalline compounds under ionising radiation is analysed. It was found that the intracenter relaxation of electronic excitations in the luminescence ion forms a physical limit for the time resolution of the scintillation detector. The limit of the time resolution, which can be provided when measuring the ionising radiation with a scintillation detector, has been established by simulation. A comparison of the time resolution limits for various errors by the electronic part of the ionising radiation detector is performed. It is shown that inorganic scintillation materials based on single crystals activated by cerium ions have a limit of 10 ps, while self-activated scintillators with low yield and short scintillation kinetics may show results not worse than 20 ps. It has been demonstrated that a further increase in the scintillation yield while keeping the short kinetics in self-activated materials can provide a better time resolution in comparison with Ce-activated materials in future detectors.
Regularities of soil temperature changes during the period with snow cover in modern climatic conditions of the Eurasian Subarctic
Authors: Kitaev Lev M.
Published: August 2021

The influence of snow cover on the dynamics of soil temperature in the modern climatic conditions of the Eurasian Subarctic was investigated through a quantitative assessment of the features of the seasonal and long-term variation of parameters. Seasonal and long-term values of soil temperature for stable snow period decrease from west to east: a decrease of snow thickness and air temperature from west to east of Eurasia leads to a weakening of the heat-insulating properties of the snow cover with a significant decrease in regional air temperatures. With the emergence of a stable snow cover, the soil temperature seasonal and long-term standard deviation sharply decreases compared to the autumn and spring periods. With the appearance of snow cover, the soil temperature standard deviation drops sharply compared to the autumn and spring periods. An exception is the northeast of Siberia: here, a relatively small thickness of snow determines a noticeable dependence of the course of soil temperature on the dynamics of surface air temperature. There are no significant long-term trends in soil temperature due to its low variability during winter period. Analysis of the course of the studied characteristics anomalies showed an insignificant and non-systematic number of their coincidences. Currently, we have not found similar research results for large regions. The revealed patterns can be used in the analysis of the results of monitoring the state of the land surface, in the development of remote sensing algorithms, in the refinement of predictive scenarios of environmental changes.
Imaginative vision of space in geopolitics: approach to study
Authors: Krastev Viliyan
Published: August 2021

The vision of space in critical geopolitics, expressed through the image, is defined. The geopolitical concept of space is interpreted as the result of the geopolitical interaction of the latter with the outside world. Its historical development, the nature of organisation and behavior in relation to other geopolitical entities play a decisive role in this regard. The accumulation of these processes over time forms the semantics of stereotypical political ideas about space, such as: mission, security, buffering, a tendency to integrate and interpenetrate attractiveness, conflict, centrality, peripherality, etc., expressing themselves in a geopolitical image. The images of space, which are becoming increasingly important in geopolitical interaction, direct modern geopolitics to a deeper understanding of the status, role and orientation of various entities expressing geopolitics. A system-representative model of the study of the geopolitical image of space as a basis of methodological orientation, presented as the main idea of the study, has been developed. The model synthesises the interaction between the main factors and elements that form the geopolitical vision of space, which are projected onto its image in a dependent relationship. With this model, we defend the idea of launching an algorithm that adequately structures the process of forming a geopolitical image of space. The attributes that determine the formation of the geopolitical image of space have been displayed: factors of perception of space of internal and external character; sources of space perception (social experience and education, art, media products, maps, media); geopolitical identification; geopolitical identity; geopolitical discourse; semantic stratification and the scale of the geopolitical image.
Assessment of economic and geographical location of regions and cities of regional submission of the Republic of Belarus
Authors: Drahun Mikalai P. , Mazan Artur S. , Dubavets Maksim A.
Published: August 2021

A methodology for assessing the economic and geographical location of the territory is proposed, which is tested on the example of regions and cities of regional submission of the Republic of Belarus. A statistically significant relationship has been established between the level of socio-economic development of the studied territories and the distance of their administrative centers to large economic centers of the country, the area of the territory, the density of highways and the length of international oil and gas pipelines passing through the territory of administrative-territorial units. An integral indicator of the economic and geographical location of regions and cities of regional submission of the Republic of Belarus is proposed. A differentiated approach to the socio-economic development of the studied territories is substantiated on the basis of a change in their economic and geographical location, in connection with which appropriate measures of a practical nature are proposed.
The importance of topography in the occurrence of glacial valleys in Belarus
Authors: Komarovskiy Michail E.
Published: August 2021

The relief of the ice-sheet bed predetermines the location of the valleys both in vast regions and in local, relatively limited areas. The influence of the relief in a large region on the formation of valleys occurs in lowland, more dissected northern and western regions of Belarus. Here, the bedrock relief plays a key role in appearance the hollow-like Vidzovsky, Polotsk and Surazh glacial erosion depressions and in isolation of the elevations separating them. The distribution of these largest forms of glacial erosion is associated with the regional picture of the glacial ice flow in topographic depressions, increased erosion of the ice bed, which developed under the glacial streams and lobes of the Scandinavian ice sheet. The degree and character of the relief dissection, the size, surface slope and orientation of the depressions, river paleo-valleys, elevations, and escarps had a leading role in the location of valleys in local, relatively limited areas. Their significance for the formation of valleys was to determine the local picture of the glacial flow and the areas where stresses were concentrated at the bed and glacial erosion intensified. The formation of tunnel valleys was possible in depressions and in the dissected relief of the glacial bed, which contributed to the accumulation of meltwater, the formation of subglacial lakes, as well as the concentration of meltwater in the subglacial channels.
A Coupled Mechanobiological Model of Muscle Regeneration In Cerebral Palsy
Authors: Khuu Stephanie , Fernandez Justin W. , Handsfield Geoffrey G.
Published: September 2021

Cerebral palsy is a neuromusculoskeletal disorder associated with muscle weakness, altered muscle architecture, and progressive musculoskeletal symptoms that worsen with age. Pathological changes at the level of the whole muscle have been shown; however, it is unclear why this progression of muscle impairment occurs at the cellular level. The process of muscle regeneration is complex, and the interactions between cells in the muscle milieu should be considered in the context of cerebral palsy. In this work, we built a coupled mechanobiological model of muscle damage and regeneration to explore the process of muscle regeneration in typical and cerebral palsy conditions, and whether a reduced number of satellite cells in the cerebral palsy muscle environment could cause the muscle regeneration cycle to lead to progressive degeneration of muscle. The coupled model consisted of a finite element model of a muscle fiber bundle undergoing eccentric contraction, and an agent-based model of muscle regeneration incorporating satellite cells, inflammatory cells, muscle fibers, extracellular matrix, fibroblasts, and secreted cytokines. Our coupled model simulated damage from eccentric contraction followed by 28 days of regeneration within the muscle. We simulated cyclic damage and regeneration for both cerebral palsy and typically developing muscle milieus. Here we show the nonlinear effects of altered satellite cell numbers on muscle regeneration, where muscle repair is relatively insensitive to satellite cell concentration above a threshold, but relatively sensitive below that threshold. With the coupled model, we show that the fiber bundle geometry undergoes atrophy and fibrosis with too few satellite cells and excess extracellular matrix, representative of the progression of cerebral palsy in muscle. This work uses in silico modeling to demonstrate how muscle degeneration in cerebral palsy may arise from the process of cellular regeneration and a reduced number of satellite cells.
The Evolution of the Hallmarks of Aging
Authors: Lemoine Maël
Published: August 2021

The evolutionary theory of aging has set the foundations for a comprehensive understanding of aging. The biology of aging has listed and described the “hallmarks of aging,” i.e., cellular and molecular mechanisms involved in human aging. The present paper is the first to infer the order of appearance of the hallmarks of bilaterian and thereby human aging throughout evolution from their presence in progressively narrower clades. Its first result is that all organisms, even non-senescent, have to deal with at least one mechanism of aging – the progressive accumulation of misfolded or unstable proteins. Due to their cumulation, these mechanisms are called “layers of aging.” A difference should be made between the first four layers of unicellular aging, present in some unicellular organisms and in all multicellular opisthokonts, that stem and strike “from the inside” of individual cells and span from increasingly abnormal protein folding to deregulated nutrient sensing, and the last four layers of metacellular aging, progressively appearing in metazoans, that strike the cells of a multicellular organism “from the outside,” i.e., because of other cells, and span from transcriptional alterations to the disruption of intercellular communication. The evolution of metazoans and eumetazoans probably solved the problem of aging along with the problem of unicellular aging. However, metacellular aging originates in the mechanisms by which the effects of unicellular aging are kept under control – e.g., the exhaustion of stem cells that contribute to replace damaged somatic cells. In bilaterians, additional functions have taken a toll on generally useless potentially limited lifespan to increase the fitness of organisms at the price of a progressively less efficient containment of the damage of unicellular aging. In the end, this picture suggests that geroscience should be more efficient in targeting conditions of metacellular aging rather than unicellular aging itself.
PEN Receptor GPR83 in Anxiety-Like Behaviors: Differential Regulation in Global vs Amygdalar Knockdown
Authors: Fakira Amanda K. , Lueptow Lindsay M. , Trimbake Nikita A. , Devi Lakshmi A.
Published: August 2021

Anxiety disorders are prevalent across the United States and result in a large personal and societal burden. Currently, numerous therapeutic and pharmaceutical treatment options exist. However, drugs to classical receptor targets have shown limited efficacy and often come with unpleasant side effects, highlighting the need to identify novel targets involved in the etiology and treatment of anxiety disorders. GPR83, a recently deorphanized receptor activated by the abundant neuropeptide PEN, has also been identified as a glucocorticoid regulated receptor (and named GIR) suggesting that this receptor may be involved in stress-responses that underlie anxiety. Consistent with this, GPR83 null mice have been found to be resistant to stress-induced anxiety. However, studies examining the role of GPR83 within specific brain regions or potential sex differences have been lacking. In this study, we investigate anxiety-related behaviors in male and female mice with global knockout and following local GPR83 knockdown in female mice. We find that a global knockdown of GPR83 has minimal impact on anxiety-like behaviors in female mice and a decrease in anxiety-related behaviors in male mice. In contrast, a local GPR83 knockdown in the basolateral amygdala leads to more anxiety-related behaviors in female mice. Local GPR83 knockdown in the central amygdala or nucleus accumbens (NAc) showed no significant effect on anxiety-related behaviors. Finally, dexamethasone administration leads to a significant decrease in receptor expression in the amygdala and NAc of female mice. Together, our studies uncover a significant, but divergent role for GPR83 in different brain regions in the regulation of anxiety-related behaviors, which is furthermore dependent on sex.
Hp-Positive Chinese Patients Should Undergo Colonoscopy Earlier and More Frequently: The Result of a Cross-Sectional Study Based on 13,037 Cases of Gastrointestinal Endoscopy
Authors: Wang Cheng , Yan Junbin , He Beihui , Zhang Shuo , Xu Sumei
Published: August 2021

Background

In China, the prevalence and mortality of colorectal cancer (CRC) have always been high, and more than 95% of CRC cases have evolved from colorectal polyps (CPs), especially adenoma. Early detection and treatment of CPs through colonoscopy is essential to reduce the incidence of CRC. Helicobacter pylori (Hp) is regarded as a risk factor for gastritis and gastric cancer and may also be a risk factor for CPs and CRC. However, few studies based on vast clinical cases exist in China to clarify whether Hp is a risk factor for CPs and CRC, and whether Hp-positive patients need to undergo colonoscopy checks earlier. This article attempts to make up for that deficiency.

Method

This cross-sectional study was conducted based on 13,037 patients without a treatment history of Hp who underwent their first gastroscopy and colonoscopy simultaneously at The First Affiliated Hospital of Zhejiang Chinese Medical University from January 2018 to December 2019. Pearson χ2 test and logistic regression were used to determine whether Hp is a risk factor for CPs and CRC. Multifactor analysis of variance was used to define the impact of Hp on CPs prevalence with different ages, sexes.

Results

For Chinese individuals, Hp is a risk factor for CPs and CRC. The odds ratio (OR) value are 1.228 (95% CI, 1.130 to 1.336) and 1.862 (95% CI 1.240-2.796), respectively. Hp-positive patients have a higher probability of multiple or large intestinal polyps. However, Hp infection does not increase the incidence of adenomas, nor does it affect the pathological type of adenomas. The OR of Hp on the risk of CPs was 1.432 (95%CI 1.275-1.608) for males but increased to 1.937 (95%CI 1.334-2.815) for those aged 35 to 40. For females, the results were similar.

Conclusions

For the Chinese, Hp is a risk factor for CPs and CRC (OR>1); the infection of Hp increased CPs risk in Chinese of all ages, especially aged 35-40, suggesting that Hp-positive patients should undergo colonoscopy frequently.
Comparison of Two Different Analgesic Prescription Strategies and Healthcare Systems: Slovenia vs. the Netherlands
Authors: Bedene Ajda , Strmljan Anita , van Dorp Eveline L. A. , Udovič Mitja , Lijfering Willem M. , Niesters Marieke , Rosendaal Frits R. , Dahan Albert , Fürst Jurij
Published: September 2021

Background: Prescribing practice of pain medication is changing in the Netherlands; opioids are used more often instead of nonsteroidal anti-inflammatory drugs (NSAIDs), therefore we aimed to compare the use of pain medication with Slovenia which has stringent prescribing rules for strong opioids.

Methods: We conducted a cohort study into national prescription databases of the Netherlands and Slovenia covering pharmacy claims between January 1, 2013 and December 31, 2019. In the analysis about 17 million Dutch and 2 million Slovenian residents were included.

Findings: The use of opioids and NSAIDs was higher in Slovenia than in the Netherlands. More frequent use of opioids in Slovenia could be almost entirely explained by weak opioids (about 6% of the population), whereas they were prescribed 50% less frequently in the Netherlands. The opioid use has increased by about 20% in the Netherlands (4.85 and 6.00% of the population in 2013 and 2018, respectively), and the majority of this increase could be explained by strong opioids (4.05% in 2018), specifically, by oxycodone whose use increased by more than 2-fold between 2013 and 2019. In comparison, oxycodone was seldomly used in Slovenia (about 0.3% of the population received a prescription in a year).

Interpretation: When medication use is controlled by stringent prescribing rules, like for strong opioids in Slovenia, the use is lower as compared to when such rules do not exist.
Continuous Monitoring of the Thermoregulatory Response in Endurance Horses and Trotter Horses During Field Exercise: Baselining for Future Hot Weather Studies
Authors: Verdegaal Elisabeth-Lidwien J. M. M. , Howarth Gordon S. , McWhorter Todd J. , Boshuizen Berit , Franklin Samantha H. , Vidal Moreno de Vega Carmen , Jonas Stacey E. , Folwell Louise E. , Delesalle Catherine J. G.
Published: August 2021

Establishing proper policies regarding the recognition and prevention of equine heat stress becomes increasingly important, especially in the face of global warming. To assist this, a detailed view of the variability of equine thermoregulation during field exercise and recovery is essential. 13 endurance horses and 12 trotter horses were equipped with continuous monitoring devices [gastrointestinal (GI) pill, heartrate (HR) monitor, and global positioning system] and monitored under cool weather conditions during four endurance rides over a total of 80 km (40 km loops) and intense trotter track-based exercise over 1,540 m. Recordings included GI temperature (Tc), speed, HR and pre- and post-exercise blood values. A temperature time profile curve of Tc was constructed, and a net area under the curve was calculated using the trapezoidal method. Metabolic heat production and oxygen cost of transport were also calculated in endurance horses. Maximum Tc was compared using an independent samples t-test. Endurance horses (mean speed 14.1 ± 1.7 km h–1) reached mean maximum Tc (39.0 ± 0.4°C; 2 × 40 km in 8 horses) during exercise at 75% of completion of Tc exercise and Tc returned to baseline within 60 min into recovery. However, the mean Tc was still 38.8 ± 0.4°C at a HR of 60 bpm which currently governs “fit to continue” competition decisions. Trotters (40.0 ± 2.9 km h–1) reached a comparable mean max Tc (38.8 ± 0.5°C; 12 horses) always during recovery. In 30% of trotters, Tc was still >39°C at the end of recovery (40 ± 32 min). The study shows that horses are individuals and thermoregulation monitoring should reflect this, no matter what type of exercise is performed. Caution is advised when using HR cut-off values to monitor thermal welfare in horses since we have demonstrated how Tc can peak quite some time after finishing exercise. These findings have implications for training and management of performance horses to safeguard equine welfare and to maximize performance.
Low-Cost Open-Source Device to Measure Maximal Inspiratory and Expiratory Pressures
Authors: Aymerich Claudia , Rodríguez-Lázaro Miguel , Solana Gorka , Farré Ramon , Otero Jorge
Published: August 2021

The measurement of maximal inspiratory (MIP) and maximal expiratory (MEP) pressures is a widely used technique to non-invasively evaluate respiratory muscle strength in clinical practice. The commercial devices that perform this test range from whole body plethysmographs to portable spirometers, both expensive and include a wide range of other respiratory tests. Given that a portable, low-cost, and specific option for MIP and MEP measuring device is not currently available in the market. A high-performance and easy-to-build prototype has been developed and the detailed technical information to easily reproduce it is freely released. A novel device is based on an Arduino microcontroller with a digital display, an integrated pressure transducer, and three-dimensional (3D) printed enclosure (total retail cost €80). The validation of the device was performed by comparison with a laboratory reference setting, and results showed accuracy within ±1%. As the device design is available according to the open-source hardware approach, measuring MIP/MEP can greatly facilitate easily available point-of-care devices for the monitoring of patients and, most important, for making this lung function measurement tool affordable to users in low- and middle-income countries.
Regional Expression of npy mRNA Paralogs in the Brain of Atlantic Salmon (Salmo salar, L.) and Response to Fasting
Authors: Tolås Ingvill , Kalananthan Tharmini , Gomes Ana S. , Lai Floriana , Norland Sissel , Murashita Koji , Rønnestad Ivar
Published: August 2021

Neuropeptide Y (NPY) is known as a potent orexigenic signal in vertebrates, but its role in Atlantic salmon has not yet been fully established. In this study, we identified three npy paralogs, named npya1, npya2, and npyb, in the Atlantic salmon genome. In silico analysis revealed that these genes are well conserved across the vertebrate’s lineage and the mature peptide sequences shared at least 77% of identity with the human homolog. We analyzed mRNA expression of npy paralogs in eight brain regions of Atlantic salmon post-smolt, and the effect of 4 days of fasting on the npy expression level. Results show that npya1 was the most abundant paralog, and was predominantly expressed in the telencephalon, followed by the midbrain and olfactory bulb. npya2 mRNA was highly abundant in hypothalamus and midbrain, while npyb was found to be highest expressed in the telencephalon, with low mRNA expression levels detected in all the other brain regions. 4 days of fasting resulted in a significant (p < 0.05) decrease of npya1 mRNA expression in the olfactory bulb, increased npya2 mRNA expression in the midbrain and decreased npyb mRNA expression in the pituitary. In the hypothalamus, the vertebrate appetite center, expression of the npy paralogs was not significantly affected by feeding status. However, we observed a trend of increased npya2 mRNA expression (p = 0.099) following 4 days of fasting. Altogether, our findings provide a solid basis for further research on appetite and energy metabolism in Atlantic salmon.
Urban Air Mobility—A 6G Use Case?
Authors: Ansari Shuja , Taha Ahmad , Dashtipour Kia , Sambo Yusuf , Abbasi Qammer H. , Imran Muhammad Ali
Published: September 2021

The increasing popularity of Unmanned Aerial Vehicles (UAV) has resulted in exponential growth of the market owing to numerous applications that have been facilitated by advances in battery technology and wireless communications. Given the successes of UAVs thus far, researchers are already gearing towards aerial transport systems that consist of dense deployment of both UAVs and Personal Aerial Vehicles (PAVs) with human passengers. Although the fifth-generation mobile network (5G) key performance indicators have been optimised to support drone use cases for both high data rates and low latency applications, future aerial transport systems will require stricter network key performance indicators to support the expected massive deployment of aerial vehicles taking into account network capacity and distance between the base station and the aerial vehicles, among others. In this article, we present our perspective, vision, architecture, requirements and key performance indicators for future aerial wireless networks supported by 6G for Urban Air Mobility (UAM). Furthermore, we review key enabling technologies and discuss future challenges for incorporating aerial wireless networks in 6G.
Epigenetic Mechanisms Underlying COVID-19 Pathogenesis
Authors: Kaneko Syuzo , Takasawa Ken , Asada Ken , Shinkai Norio , Bolatkan Amina , Yamada Masayoshi , Takahashi Satoshi , Machino Hidenori , Kobayashi Kazuma , Komatsu Masaaki , Hamamoto Ryuji
Published: September 2021

In 2019, a novel severe acute respiratory syndrome called coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was reported and was declared a pandemic by the World Health Organization (WHO) in March 2020. With the advancing development of COVID-19 vaccines and their administration globally, it is expected that COVID-19 will converge in the future; however, the situation remains unpredictable because of a series of reports regarding SARS-CoV-2 variants. Currently, there are still few specific effective treatments for COVID-19, as many unanswered questions remain regarding the pathogenic mechanism of COVID-19. Continued elucidation of COVID-19 pathogenic mechanisms is a matter of global importance. In this regard, recent reports have suggested that epigenetics plays an important role; for instance, the expression of angiotensin I converting enzyme 2 (ACE2) receptor, an important factor in human infection with SARS-CoV-2, is epigenetically regulated; further, DNA methylation status is reported to be unique to patients with COVID-19. In this review, we focus on epigenetic mechanisms to provide a new molecular framework for elucidating the pathogenesis of SARS-CoV-2 infection in humans and of COVID-19, along with the possibility of new diagnostic and therapeutic strategies.
Frac-n-Flow Testing to Screen Brittle Fracture Stages in Wolfcamp Formation, Permian Basin, USA
Authors: Zeng Zhengwen
Published: September 2021

A new technique, fracturing-and-flowing (frac-n-flow) testing, is introduced for horizontal drilling and multistage hydraulic fracturing (HDMHF) practitioners to check if the next stage would be a brittle fracture using the instantaneous shut-in pressure (ISIP) from the current stage. It was developed to reduce the number of not-flowing clusters in HDMHF treatments due to stress shadows in the development of tight oil reserves in Wolfcamp, Permian Basin, USA, and other similar fields. Preliminary frac-n-flow testing results show that a medium (200–1000 psi) increase in confining pressure under representative field in-situ stresses can transfer Indiana limestone from brittle fracturing to semi-ductile failing. Consequently, folds of increase (FOI) of matrix permeability vary from +13 (i.e., increase by 1300%) to −0.39 (i.e., decrease by 39%). Limestone is one of the major lithological components in Wolfcamp formation. Field ISIP data of two HDMHF wells in Wolfcamp formation show that the maximum stress shadows are +1297 psi and +1716 psi, respectively. These stress shadows might have transferred the fracturing process from brittle to semi-ductile, converting the corresponding stages from being stimulated and conductive (fracturing-n-flowing) to being damaged and not-flowing (failing-n-not-flowing). Field completion reports of the two wells confirmed that screen-out and other interruptions of operation occurred in these high stress shadowed stages.
A Systematic Review of Key Challenges in Hybrid HVAC–HVDC Grids
Authors: Javed Umar , Mughees Neelam , Jawad Muhammad , Azeem Omar , Abbas Ghulam , Ullah Nasim , Chowdhury Md. Shahariar , Techato Kuaanan , Zaidi Khurram Shabih , Tahir Umair
Published: September 2021

The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC–HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC–HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC–HVDC grids, current developments, and future research directions and prospects, which have led to the evolution of this field. Therefore, the motivation, novelty, and the main contribution of the survey is to comprehensively analyze the integration challenges, implemented control algorithms, employed optimization algorithms, and major security challenges of hybrid HVAC–HVDC systems. Moreover, future research prospects are identified, such as security algorithms’ constraints, dynamic contingency modeling, and cost-effective and reliable operation.
Production of Acrylic Acid from Biomass-Derived Fumaric Acid under Hydrothermal Conditions
Authors: Yin Guodong , Zhong Heng , Yao Guodong , Jin Fangming , Zhao Jianfu
Published: September 2021

Production of energy and chemicals from biomass resources has been regarded as one promising method to address the challenge of global warming. In this research, production of acrylic acid from fumaric acid, one of the biomass-derived building blocks, is proposed. CuO was employed as a solid oxidant, which showed excellent activity and selectivity for the production of acrylic acid, and water played an essential role in acting as not only a solvent but also a catalyst in this process. An optimum acrylic acid yield of 76.4% was successfully obtained after the reaction of fumaric acid with CuO at 300 °C for only 60 s.This research provides a green and highly efficient way to produce value-added chemicals from biomass-derived building blocks, and thus is promising for practical application.
Food Choices and Their Impact on Health and Environment
Authors: Szalonka Katarzyna , Stańczyk Elżbieta , Gardocka-Jałowiec Anna , Waniowski Paweł , Niemczyk Agata , Gródek-Szostak Zofia
Published: September 2021

Food choices are complex and highly variable, even over short periods, as they are influenced by numerous psychological, social, and cultural factors, in addition to biological and economic ones. Consumer choices are increasingly complex because of the growing quantity and variety of available food products, which also affects individuals’ environments. This paper is part of a larger study on health-related food choices, and it discusses how food choices affect the environment. To achieve the research goal, classes of respondents that are homogeneous in their food choices were identified. The authors used an algorithm to build classification trees and found that health status is determined by respondents’ age and food consumption habits. The paper demonstrates that understanding individual nutritional choices is a prerequisite for changing consumption habits and shaping healthy behavior, which is in line with the principle of sustainable development through sustainable consumption. The findings are relevant to public health researchers and practitioners who wish to understand the relationship between nutritional practices and health in line with sustainable development.
An Expert-Driven Probabilistic Assessment of the Safety and Security of Offshore Wind Farms
Authors: Ramírez-Agudelo Oscar Hernán , Köpke Corinna , Guillouet Yann , Schäfer-Frey Jan , Engler Evelin , Mielniczek Jennifer , Sill Torres Frank
Published: September 2021

Offshore wind farms (OWFs) are important infrastructure which provide an alternative and clean means of energy production worldwide. The offshore wind industry has been continuously growing. Over the years, however, it has become evident that OWFs are facing a variety of safety and security challenges. If not addressed, these issues may hinder their progress. Based on these safety and security goals and on a Bayesian network model, this work presents a methodological approach for structuring and organizing expert knowledge and turning it into a probabilistic model to assess the safety and security of OWFs. This graphical probabilistic model allowed us to create a high-level representation of the safety and security state of a generic OWF. By studying the interrelations between the different functions of the model, and by proposing different scenarios, we determined the impacts that a failing function may have on other functions in this complex system. Finally, this model helped us define the performance requirements of such infrastructure, which should be beneficial for optimizing operation and maintenance.
Procedure for the Accurate Modelling of Ring Induction Motors
Authors: Tomczyk Krzysztof , Makowski Tomasz , Kowalczyk Małgorzata , Ostrowska Ksenia , Beńko Piotr
Published: September 2021

This paper proposes a procedure for the accurate modelling of the ring induction motors (RIMs), based on the Monte Carlo (MC) method and the relations presented in the relevant metrology guidelines. Modelling was carried out based on the measured data for the torque-slip characteristic (TSC) and using the equivalent circuit for the RIM. The parameters included an extended Kloss equation (EKE) and the associated uncertainties were determined using the MC method. The polynomial procedure was applied as a numerical tool to complement the MC method to determine the power losses in the stator iron and the relevant uncertainty. This is in line with international standards for the theory of uncertainty application in the field of engineering. The novelty of this paper refers to the accurate modelling of the RIMs obtained by determining the corresponding uncertainties. The procedure presented in this paper was developed based on the assumption that the parameters of the equivalent circuit are independent of the temperature, influence of core saturation, and the phenomenon of current displacement. Our procedure can be successfully used for both the theoretical calculations related to the modelling of the RIMs, and in practical applications involving detailed measurements and the corresponding uncertainties. The use of the MC method allowed for significant improvement in the modelling results, in terms of both the TSC and EKE.
Differences of Main Enrichment Factors of S1l11-1 Sublayer Shale Gas in Southern Sichuan Basin
Authors: Shi Xuewen , Luo Chao , Cao Gaohui , He Yifan , Li Yi , Zhong Kesu , Jiang Wenbin , Lin Mian
Published: September 2021

In this study, shale cores from 20 wells in the S1l11-1 sublayer of Longmaxi Formation buried in shallow shale (<3500 m) and deep shale (>3500 m) in the southern Sichuan Basin, China were collected to compare their pore structures and gas-bearing properties using multiple experiments. Results showed that the deep layer has relatively lower brittle mineral content, which is disadvantageous in terms of the higher requirements it imposes on hydraulic fracturing. Results also showed that the most important factor controlling the differential enrichment of S1l11-1 shale gas in southern Sichuan Basin is porosity. Moreover, the porosity composition of shallow shale and deep shale has significant differences: the porosity of shallow shale is dominated by organic pores, while for deep shale, both organic and inorganic pores are important. The inorganic pores provide significant storage space for free gas in deep shale; their contribution warrants more attention. We also found that the difference in organic porosity of the shallow and deep shale samples resulted from large differences in pore development ability, while the highest inorganic porosity was concentrated near the optimal mineral composition when the content of quartz plus feldspar plus pyrite was about 70%. This study revealed the primary factor controlling the difference in gas content between shallow and deep shale and detailed the characteristics of microscopic pore structure, providing a basis for the exploration and development of deep shale gas in the Wufeng-Longmaxi Formation in the southern Sichuan Basin.
A Study of the Dependence of the Mach Stem Height on the Trailing Edge Height
Authors: Bai Chen-Yuan , Wu Zi-Niu
Published: September 2021

The Mach stem height is an important parameter in the Mach reflection of steady supersonic flow. Various experimental, numerical, and theoretical works have been conducted to study this parameter in the past. However, much of the established work focuses around a single set of trailing edge heights. Here, we perform a study to show the dependence of Mach stem height on the trailing edge height for a wider range of geometry. Through numerical simulation for a set of trailing edge heights, we found that the normalized Mach stem height is almost linear with respect to the normalized wedge trailing edge height. The parameter used for normalization can be either the inlet height or the length of the lower wedge surface. The observation of this linear trend is justified through a simplified analysis, which leads to an expression of the Mach stem height that linearly depends on the trailing edge height. The present study extends our knowledge about how the geometry affects the Mach stem height, and provides a basis for future work to elaborate analytical models for Mach stem height.
tat- Eyleminin Anlam Genişlemesi Üzerine Bir İnceleme
Authors: BAŞ Melike
Published: August 2021

İmgesel dilin temelini oluşturan bedenlerimiz ve fiziksel deneyimlerimiz aynı zamanda metaforik kavramlaştırmaların oluşumunda rol oynayan duyusal kanallar ile ayrılmaz bir şekilde bağlantılıdır ve bedenleşmiş bilişin özünde yer almaktadır. Bu bağlamda, bu çalışma, beş temel duyudan biri olan tatma duyusunu ifade etmek için kullanılan tat- eyleminin derlem verisinden elde edilen eşdizimlilik örüntülerine ve bağımlı dizinlere odaklanarak söz konusu eylemin kullanım bağlamında sunduğu çokanlamlı doğasına dair bilgi sahibi olmayı amaçlamaktadır. Bu amaçla, Türkçe Ulusal Derlem v3’ten elde edilen eşdizim oluşturduğu ilk yüz sözcük anlam alanlarına göre sınıflandırılmış ve bağımlı dizin satırları incelenmiştir. Çalışma sonuçları, tatma duyusunun ‘yemek’ kavram alanının yanı sıra, duygular, soyut kavramlar, bilişsel durumların ifadesinde kullanıldığını göstermektedir. Ayrıca, farklı duyuların (görme, işitme, koklama, dokunma) ifadelerinde sinestezik bir anlam taşıdığı da tespit edilmiştir. Çalışmada elde edilen DENEYİMLEMEK TATMAKTIR, FARKINA VARMAK / BİLMEK / ÖĞRENMEK TATMAKTIR ve BİR DUYGUYU HİSSETMEK TATMAKTIR metaforları, BİLİŞ ALGIDIR üst-metaforu ile örtüşmekte ve önceki çalışmaların bulgularına paralellik göstermektedir.
Folklor ile Tiyatronun Metinlerarası Yolculuğu: Yunus Emre Tiyatrosu Örneği
Authors: ULUTÜRK SAKARYA Yasemin
Published: August 2021

Kültürel mirasın önemli unsurlarından folklor, çok eski zamanlardan günümüze çeşitli yöntemler ile aktarıla gelmiştir. Bu yöntemlerden biri olan metinlerarasılık, var olanın yeni bir bağlamda yeniden ele alınmasını sağlarken hem metnin kendisinden öncekiler ile ilişkisini ortaya koymakta hem de hiçbir metnin diğerlerinden tamamen bağımsız olamayacağını somutlaştırmaktadır. Bu anlamda toplumu yansıtma görevi ile temelde insanı konu alan tiyatro, Türk kültürünün parçasını oluşturan folkloru diyaloglarına işleyerek hem aslî vazifesini yerine getirmekte hem de folklorik ögelerin unutulmasının önüne geçerek metinlerarası bir alışverişin gerçekleşmesini sağlamaktadır. Yunus Emre adlı tiyatro ise Recep Bilginer'in bu minvalde kaleme aldığı bir metindir. Eserde selamlaşma, hediyeleşme, düğün gibi çeşitli gelenek ve görenekler ile ilahi, nefes, türkü, tekerleme gibi sözlü edebî türlere yer verilmesi, folklorun tiyatroda metinlerarası olarak canlandığını göstermektedir. Ayrıca hayatı folklor unsurları ile örülü olan Yunus Emre'nin tiyatro gibi farklı bir bağlamda yeniden ele alınması o unsurların canlanmasını daha gerçekçi kılarken metinlerarasılığı müşahhas hâle getirmekte, diyaloglara işlenmesini de kolaylaştırmaktadır.