bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-Hyperglycaemic Evaluation of Buddleia indica Leaves Using In Vitro, In Vivo and In Silico Studies and Its Correlation with the Major Phytoconstituents
Authors: Elhady Sameh S. , Youssef Fadia S. , Alahdal Abdulrahman M. , Almasri Diena M. , Ashour Mohamed L.
Published: November 2021

Buddleia indica Lam. is an ornamental evergreen shrub with few reports concerning its phytoconstituents and biological activities. Herein, the antihyperglycaemic activity of B. indica leaves methanol extract (BIT) was evaluated for the first time using in vitro and in vivo studies. Molecular modelling was performed for its major phytoconstituents that were further subjected to ADME/TOPAKT (absorption, distribution, metabolism, excretion and toxicity) prediction. BIT revealed considerable reduction in glucose concentration by 9.93% at 50 μg/mL using 3T3-L1 adipocyte culture. It displayed substantial inhibition versus α-glucosidase and α-amylase with IC50 205.2 and 385.06 μg/mL, respectively. In vivo antihyperglycaemic activity of BIT and the ethyl acetate fraction (BIE) was performed using streptozotocin-induced diabetes in rat model. BIT and BIE effectively ameliorate oxidative stress markers in addition to reducing serum blood glucose by 56.08 and 54.00%, respectively, and are associated with a substantial increase in serum insulin by 4.1 and 12.7%, respectively. This can be attributed to its richness with polyphenolic compounds comprising flavonoids, phenolic acids, phenyl propanoids and iridoids. Molecular docking showed that verbascoside and kaempferol displayed the highest fitting within human α-amylase (HA) and human α-glucosidase (HG) active sites, respectively. They showed reasonable pharmacokinetic, pharmacodynamic and toxicity properties, as revealed by ADME/TOPKAT study.
Water Regime Monitoring of the Royal Walnut (Juglans regia L.) Using Sap Flow and Dendrometric Measurements
Authors: Bárek Viliam , Kováčová Martina , Kišš Vladimír , Paulen Oleg
Published: November 2021

Changes in the distribution of annual rainfall totals, together with the increase in temperature over the last 40 years, are causing more frequent periods of drought, and plants are more often exposed to water stress. The aim of this study was to monitor the effect of different water regimes (irrigated and non-irrigated) of individuals of walnut tree (Juglans regia L.) in a private orchard located in the West of Slovakia. Our research was focused on dendrometric and sap flow measurements in the period from 28 March to 2 June 2019. The results showed differences in the sap flow of walnut trees during the budbreak period: when trees were irrigated, sap flow in the diurnal cycle was around 130 g·h−1 (20.48%), higher than in the non-irrigated treatment. Dendrometric differences between the irrigated and non-irrigated treatments were not significant. The sap flow data in the flowering period of the irrigated variant were slightly higher at 150 g·h−1 (35.62%) than non-irrigated. Dendrometric differences were more significant when the difference between the variants was more than 1.5 mm. Continuation of this research and analysis of the data obtained in the coming years will allow us to evaluate the effects of the environment on fruit trees in the long term.
Transient Waterlogging Events Impair Shoot and Root Physiology and Reduce Grain Yield of Durum Wheat Cultivars
Authors: Cotrozzi Lorenzo , Lorenzini Giacomo , Nali Cristina , Pisuttu Claudia , Pampana Silvia , Pellegrini Elisa
Published: November 2021

Durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) is a staple crop of the Mediterranean countries, where more frequent waterlogging events are predicted due to climate change. However, few investigations have been conducted on the physiological and agronomic responses of this crop to waterlogging. The present study provides a comprehensive evaluation of the effects of two waterlogging durations (i.e., 14 and 35 days) on two durum wheat cultivars (i.e., Svevo and Emilio Lepido). An integrated analysis of an array of physiological, biochemical, biometric, and yield parameters was performed at the end of the waterlogging events, during recovery, and at physiological maturity. Results established that effects on durum wheat varied depending on waterlogging duration. This stress imposed at tillering impaired photosynthetic activity of leaves and determined oxidative injury of the roots. The physiological damages could not be fully recovered, subsequently slowing down tiller formation and crop growth, and depressing the final grain yield. Furthermore, differences in waterlogging tolerance between cultivars were discovered. Our results demonstrate that in durum wheat, the energy maintenance, the cytosolic ion homeostasis, and the ROS control and detoxification can be useful physiological and biochemical parameters to consider for the waterlogging tolerance of genotypes, with regard to sustaining biomass production and grain yield.
Colour Fastness to Various Agents and Dynamic Mechanical Characteristics of Biocomposite Filaments and 3D Printed Samples
Authors: Muck Deja , Tomc Helena Gabrijelčič , Elesini Urška Stanković , Ropret Maruša , Leskovšek Mirjam
Published: November 2021

The aim of the study was to analyse the colour fastness of 3D printed samples that could be used as decorative or household items. Such items are often fabricated with 3D printing. The colour of filaments affects not only the mechanical properties, but also the appearance and user satisfaction. Samples of biocomposite filaments (PLA and PLA with added wood and hemp fibres) were used. First, the morphological properties of the filaments and 3D printed samples were analysed and then, the colour fastness against different agents was tested (water, oil, detergent, light and elevated temperature). Finally, the dynamic mechanical properties of the filaments and 3D printed samples were determined. The differences in the morphology of the filaments and 3D printed samples were identified with SEM analysis. The most obvious differences were observed in the samples with wood fibres. All printed samples showed good resistance to water and detergents, but poorer resistance to oil. The sample printed with filaments with added wood fibres showed the lowest colour fastness against light and elevated temperatures. Compared to the filaments, the glass transition of the printed samples increased, while their stiffness decreased significantly. The lowest elasticity was observed in the samples with wood fibres. The filaments to which hemp fibres were added showed the reinforcement effect. Without the influence on their elasticity, the printed samples can be safely used between 60 and 65 °C.
Ternary Nanocomposite System Composing of Graphene Nanoplatelet, Cellulose Nanofiber and Jatropha Oil Based Waterborne Polyurethane: Characterizations, Mechanical, Thermal Properties and Conductivity
Authors: Amri Mohamad Ridzuan , Md Yasin Faizah , Abdullah Luqman Chuah , Al-Edrus Syeed Saifulazry Osman , Mohamad Siti Fatahiyah
Published: November 2021

This work aims to evaluate the performance of graphene nanoplatelet (GNP) as conductive filler with the presence of 0.5 wt.% cellulose nanofiber (CNF) on the physical, mechanical, conductivity and thermal properties of jatropha oil based waterborne polyurethane. Polyurethane was made from crude jatropha oil using an epoxidation and ring-opening process. 0.5, 1.0, 1.5, 2.0 wt.% GNP and 0.5 wt.% CNF were incorporated using casting method to enhance film performance. Mechanical properties were studied following standard method as stated in ASTM D638-03 Type V. Thermal stability of the nanocomposite system was studied using thermal gravimetric analysis (TGA). Filler interaction and chemical crosslinking was monitored using Fourier-transform infrared spectroscopy (FTIR) and film morphology were observed with field emission scanning electron microscopy (FESEM). Water uptake analysis, water contact angle and conductivity tests are also carried out. The results showed that when the GNP was incorporated at fixed CNF content, it was found to enhance the nanocomposite film, its mechanical, thermal and water behavior properties as supported by morphology and water uptake. Nanocomposite film with 0.5 wt.% GNP shows the highest improvement in term of tensile strength, Young’s modulus, thermal degradation and water behavior. As the GNP loading increases, water uptake of the nanocomposite film was found relatively small (<1%). Contact angle test also indicates that the film is hydrophobic with addition of GNP. The conductivity properties of the nanocomposite film were not enhanced due to electrostatic repulsion force between GNP sheet and hard segment of WBPU. Overall, with addition of GNP, mechanical and thermal properties was greatly enhanced. However, conductivity value was not enhanced as expected due to electrostatic repulsion force. Therefore, ternary nanocomposite system is a suitable candidate for coating application.
Chitosan/Polyvinyl Alcohol/Tea Tree Essential Oil Composite Films for Biomedical Applications
Authors: Castro Jorge Iván , Valencia-Llano Carlos Humberto , Valencia Zapata Mayra Eliana , Restrepo Yilmar Joan , Mina Hernandez José Herminsul , Navia-Porras Diana Paola , Valencia Yamid , Valencia Cesar , Grande-Tovar Carlos David
Published: November 2021

Tissue engineering is crucial, since its early adoption focused on designing biocompatible materials that stimulate cell adhesion and proliferation. In this sense, scaffolds made of biocompatible and resistant materials became the researchers’ focus on biomedical applications. Humans have used essential oils for a long time to take advantage of their antifungal, insecticide, antibacterial, and antioxidant properties. However, the literature demonstrating the use of essential oils for stimulating biocompatibility in new scaffold designs is scarce. For that reason, this work describes the synthesis of four different film composites of chitosan/polyvinyl alcohol/tea tree (Melaleuca alternifolia), essential oil (CS/PVA/TTEO), and the subdermal implantations after 90 days in Wistar rats. According to the Young modulus, DSC, TGA, mechanical studies, and thermal studies, there was a reinforcement effect with the addition of TTEO. Morphology and energy-dispersive (EDX) analysis after the immersion in simulated body fluid (SBF) exhibited a light layer of calcium chloride and sodium chloride generated on the material’s surface, which is generally related to a bioactive material. Finally, the biocompatibility of the films was comparable with porcine collagen, showing better signs of resorption as the amount of TTEO was increased. These results indicate the potential application of the films in long-term biomedical needs.
Distributed Humidity Sensing in Concrete Based on Polymer Optical Fiber
Authors: Lu Xin , Hicke Konstantin , Breithaupt Mathias , Strangfeld Christoph
Published: November 2021

We present a preliminary investigation on distributed humidity monitoring during the drying process of concrete based on an embedded polymer optical fiber (POF). The water dissipated into the POF changes several properties of the fiber such as refractive index, scattering coefficient and attenuation factor, which eventually alters the Rayleigh backscattered light. The optical time domain reflectometer (OTDR) technique is performed to acquire the backscattered signal at the wavelengths 650 nm and 500 nm, respectively. Experimental results show that the received signal increases at 650 nm while the fiber attenuation factor clearly increases at 500 nm, as the concrete dries out. In the hygroscopic range, the information retrieved from the signal change at 650 nm agrees well with the measurement result of the electrical humidity sensors also embedded in the concrete sample.
Serum Albumin Nanoparticles: Problems and Prospects
Authors: Hornok Viktória
Published: November 2021

The present paper aims to summarize the results regarding serum albumin-based nanoparticles (NPs) for drug delivery purposes. In particular, it focuses on the relationship between their preparation techniques and synthesis parameters, as well as their successful clinical application. In spite of the huge amount of consumed material and immaterial sources and promising possibilities, products made from different types of albumin NPs, with the exception of a few, still have not been invented. In the present paper, promising applications of serum albumin nanoparticles (SANPs) for different biomedical purposes, such as carriers, delivery systems and contrast agents, are also discussed. The most frequent utilization of the NPs for certain diseases, i.e., cancer therapy, and future prospects are also detailed in this study.
Large-Area Fabrication of Structurally Colored and Humidity Sensitive Composite Nanofilm via Ultrasonic Spray-Coating
Authors: Li Sijun , Kou Donghui , Zhang Shufen , Ma Wei
Published: November 2021

Intelligent structural colors have received extensive attention in recent years due to their diverse applications. However, the large-area, uniform, and cost-effective fabrication of ultra-thin structural color films is still challenging. Here, for the first time, we design and employ an ultrasonic spray-coating technique with non-toxic, green nano-silica and polyvinylpyrrolidone as raw materials, to prepare structural color films on silicon wafers. Due to the addition of polyvinylpyrrolidone, the coffee-ring effect during droplet drying is suppressed and uniform composite films are formed. We further perform a detailed study of the influence of various processing parameters including silica/polyvinylpyrrolidone concentration, substrate temperature, nozzle-to-substrate distance, and number of spray-passes on film roughness and thickness. By increasing the number of spray-passes from 10 to 30, the film thickness from 120 to 340 nm is modulated, resulting in different colors, and large-area and uniform colors on commercial round silicon wafers with 15 cm diameter are achieved. The silica/polyvinylpyrrolidone composite films show strong hydrophilicity and are sensitive to humidity changes, leading to quickly tunable and reversible structural colors. Quartz crystal microbalance with dissipation demonstrates water vapor adsorption and condensation on the nanofilm when increasing environmental humidity. Thereby, ultrasonic spray-coating as a novel film fabrication technique provides a feasible scheme for large-area preparation of intelligent structural colors.
Self-Healing Hydrogels: Preparation, Mechanism and Advancement in Biomedical Applications
Authors: Devi V. K. Anupama , Shyam Rohin , Palaniappan Arunkumar , Jaiswal Amit Kumar , Oh Tae-Hwan , Nathanael Arputharaj Joseph
Published: November 2021

Polymeric hydrogels are widely explored materials for biomedical applications. However, they have inherent limitations like poor resistance to stimuli and low mechanical strength. This drawback of hydrogels gave rise to ‘‘smart self-healing hydrogels’’ which autonomously repair themselves when ruptured or traumatized. It is superior in terms of durability and stability due to its capacity to reform its shape, injectability, and stretchability thereby regaining back the original mechanical property. This review focuses on various self-healing mechanisms (covalent and non-covalent interactions) of these hydrogels, methods used to evaluate their self-healing properties, and their applications in wound healing, drug delivery, cell encapsulation, and tissue engineering systems. Furthermore, composite materials are used to enhance the hydrogel’s mechanical properties. Hence, findings of research with various composite materials are briefly discussed in order to emphasize the healing capacity of such hydrogels. Additionally, various methods to evaluate the self-healing properties of hydrogels and their recent advancements towards 3D bioprinting are also reviewed. The review is concluded by proposing several pertinent challenges encountered at present as well as some prominent future perspectives.
Multiscale Modeling and Simulation of Polymer Blends in Injection Molding: A Review
Authors: Deng Lin , Fan Suo , Zhang Yun , Huang Zhigao , Zhou Huamin , Jiang Shaofei , Li Jiquan
Published: November 2021

Modeling and simulation of the morphology evolution of immiscible polymer blends during injection molding is crucial for predicting and tailoring the products’ performance. This paper reviews the state-of-the-art progress in the multiscale modeling and simulation of injection molding of polymer blends. Technological development of the injection molding simulation on a macroscale was surveyed in detail. The aspects of various models for morphology evolution on a mesoscale during injection molding were discussed. The current scale-bridging strategies between macroscopic mold-filling flow and mesoscopic morphology evolution, as well as the pros and cons of the solutions, were analyzed and compared. Finally, a comprehensive summary of the above models is presented, along with the outlook for future research in this field.
Influence of Silicone Rubber Coating on the Characteristics of Surface Streamer Discharge
Authors: Meng Xiaobo , Wang Liming , Mei Hongwei , Zhang Chuyan
Published: November 2021

A pollution flashover along an insulation surface—a catastrophic accident in electrical power system—threatens the safe and reliable operation of a power grid. Silicone rubber coatings are applied to the surfaces of other insulation materials in order to improve the pollution flashover voltage of the insulation structure. It is generally believed that the hydrophobicity of the silicone rubber coating is key to blocking the physical process of pollution flashover, which prevents the formation of continuously wet pollution areas. However, it is unclear whether silicone rubber coating can suppress the generation of pre-discharges such as corona discharge and streamer discharge. In this research, the influence of silicone rubber coating on the characteristics of surface streamer discharge was researched in-depth. The streamer ‘stability’ propagation fields of the polymer are lower than that of the polymer with silicone rubber coating. The velocities of the streamer propagation along the polymer are higher than those along the polymer with silicone rubber coating. This indicates that the surface properties of the polymer with the silicone rubber coating are less favorable for streamer propagation than those of the polymer.
Divine Logos and Translation among Iberian Muslims: From Ibn Ḥazm (d. 456H/1064CE) to Aḥmad al-Ḥanafī (d. 1049H/1650CE)
Authors: Colominas Aparicio Mònica
Published: November 2021

Like other religious traditions, Islam has accommodated notions of the divine logos. The actual elaboration of these notions has been heavily dependent on how the translation of God’s word and commandments to humans were understood as an object of intra-community debate, as well as in polemics with non-Muslims (inter-community debate). These two debates converged in the Muslim critique of the translation, transmission, and interpretation of the divine logos by Jews and Christians in their scriptures, although such convergence took different forms in different historical settings. The present contribution focuses on several examples of the engagement of Muslims with the Bible in the medieval Iberian Peninsula and in exile. The choice of authors and works ranges from the 11th-century Andalusī scholar Ibn Ḥazm to the exile Aḥmad al-Ḥanafī (d. 1049H/1650CE). It is nevertheless not intended as a comprehensive overview of Muslim approaches from the Western Mediterranean region. The objective is rather to discuss several aspects associated with the translation of the divine logos in polemics as a tool of identity that is intimately related to Muslim practices of exegesis and transmission of the Jewish and Christian writings. Particular attention is directed toward the broader issue of how notions of the translation of God’s word have been informed by language practices within contexts of inter-religious contact and competition (either between existing social bodies or as references to a relatively recent past). A preliminary look at Muslim modes of scriptural interpretation suggests that translation and exegesis, as well as the ways in which Muslims understood these practices as performed by non-Muslims, were part of a tradition that took final form and meaning, and that was subject to change when re-enacted in specific contexts. Any understanding of the subject must be read against the backdrop of Muslim configurations of knowledge within the local communities, as combined with tradition.
Dialogue or Narrative? Exploring Tensions between Interpretations of Genesis 38
Authors: Dickman Nathan Eric , Spann Joy
Published: November 2021

We examine dialectical tensions between “dialogue” and “narrative” as these discourses supplant one another as the fundamental discourse of intelligibility, through juxtaposing two interpretations of Genesis 38 rooted in changing interpretative paradigms. Is dialogue properly understood as a narrative genre, or is narrative the content about which people are in dialogue? Is the divine–human relationship a narrative drama or is it a dialogue between a god and human beings? We work within parameters laid out by the philosophical hermeneutics of Gadamer (primarily representing dialogue) and Ricoeur (primarily representing narrative). On the one hand, a feminist approach can develop Tamar as a courageous hero in impossible circumstances, strategizing to overturn Judah’s patriarchal naïveté. On the other hand, Judah seems to be able to be read as a tragic hero, seeking to save Tamar. These readings challenge one another, where either Tamar’s or Judah’s autonomy is undermined. By putting these interpretations into dialogue, our aim is to show that neither dialogue nor narrative succeeds the other with finality, and that we can achieve a fragile integration of the two (dialogue and narrative) despite their propensity toward polarization.
Dynamical Downscaling of Temperature Variations over the Canadian Prairie Provinces under Climate Change
Authors: Zhou Xiong , Huang Guohe , Li Yongping , Lin Qianguo , Yan Denghua , He Xiaojia
Published: November 2021

In this study, variations of daily mean, maximum, and minimum temperature (expressed as Tmean, Tmax, and Tmin) over the Canadian Prairie Provinces were dynamically downscaled through regional climate simulations. How the regional climate would increase in response to global warming was subsequently revealed. Specifically, the Regional Climatic Model (RegCM) was undertaken to downscale the boundary conditions of Geophysical Fluid Dynamics Laboratory Earth System Model Version 2M (GFDL-ESM2M) over the Prairie Provinces. Daily temperatures (i.e., Tmean, Tmax, and Tmin) were subsequently extracted from the historical and future climate simulations. Temperature variations in the two future periods (i.e., 2036 to 2065 and 2065 to 2095) are then investigated relative to the baseline period (i.e., 1985 to 2004). The spatial distributions of temperatures were analyzed to reveal the regional impacts of global warming on the provinces. The results indicated that the projected changes in the annual averages of daily temperatures would be amplified from the southwest in the Rocky Mountain area to the northeast in the prairie region. It was also suggested that the projected temperature averages would be significantly intensified under RCP8.5. The projected temperature variations could provide scientific bases for adaptation and mitigation initiatives on multiple sectors, such as agriculture and economic sectors over the Canadian Prairies.
Satellite Image Classification Using a Hierarchical Ensemble Learning and Correlation Coefficient-Based Gravitational Search Algorithm
Authors: Thiagarajan Kowsalya , Manapakkam Anandan Mukunthan , Stateczny Andrzej , Bidare Divakarachari Parameshachari , Kivudujogappa Lingappa Hemalatha
Published: November 2021

Satellite image classification is widely used in various real-time applications, such as the military, geospatial surveys, surveillance and environmental monitoring. Therefore, the effective classification of satellite images is required to improve classification accuracy. In this paper, the combination of Hierarchical Framework and Ensemble Learning (HFEL) and optimal feature selection is proposed for the precise identification of satellite images. The HFEL uses three different types of Convolutional Neural Networks (CNN), namely AlexNet, LeNet-5 and a residual network (ResNet), to extract the appropriate features from images of the hierarchical framework. Additionally, the optimal features from the feature set are extracted using the Correlation Coefficient-Based Gravitational Search Algorithm (CCGSA). Further, the Multi Support Vector Machine (MSVM) is used to classify the satellite images by extracted features from the fully connected layers of the CNN and selected features of the CCGSA. Hence, the combination of HFEL and CCGSA is used to obtain the precise classification over different datasets such as the SAT-4, SAT-6 and Eurosat datasets. The performance of the proposed HFEL–CCGSA is analyzed in terms of accuracy, precision and recall. The experimental results show that the HFEL–CCGSA method provides effective classification over the satellite images. The classification accuracy of the HFEL–CCGSA method is 99.99%, which is high when compared to AlexNet, LeNet-5 and ResNet.
Meta-Analysis in Using Satellite Precipitation Products for Drought Monitoring: Lessons Learnt and Way Forward
Authors: Hinge Gilbert , Mohamed Mohamed M. , Long Di , Hamouda Mohamed A.
Published: November 2021

In recent years, satellite precipitation products (SPPs) have emerged as an essential source of data and information. This work intends to summarize lessons learnt on using SPPs for drought monitoring and to propose ways forward in this field of research. A thorough literature review was conducted to review three aspects: effects of climate type, data record length, and time scale on SPPs performance. The conducted meta-analysis showed that the performance of SPPs for drought monitoring largely depends upon the climate type of the location and length of the data record. SPPs drought monitoring performance was shown to be higher in temperate and tropical climates than in dry and continental ones. SPPs were found to perform better with an increase in data record length. From a general standpoint, SPPs offer great potential for drought monitoring, but the performance of SPPs needs to be improved for operational purposes. The present study discusses blending SPPs with in situ data and other lessons learned, as well as future directions of using SPPs for drought applications.
The Intriguing Structure of Stripes in GRACE Geopotential Models
Authors: Pagiatakis Spiros , Peidou Athina
Published: November 2021

Geopotential models derived from Gravity Recovery and Climate Experiment (GRACE) mission measurements are significantly obscured by the presence of a systematic artifact, known as longitudinal stripes. Based on our previous work (Peidou and Pagiatakis, 2020) we provide an in-depth analysis of the latitudinal sampling characteristics of GRACE and we reveal the intriguing sampling mechanism that creates sub-Nyquist artifacts (stripes). Because the sub-Nyquist artifacts are poorly understood, we provide a simple simulation example to elucidate the mechanism of the sub-Nyquist artifact generation. Subsequently, we randomly select June 2009 daily GPS precise science orbits for GRACE-A to produce ground tracks to sample the low frequency disturbing potential (geoid) along the parallel of ϕ=10° N. The sampled geoid is then deinterlaced in space to produce a monthly data sequence whose detailed analysis shows that the sub-Nyquist artifacts (stripes) are produced from a critical sampling rate of the low degree gravitational field that is related to the ratio m/n of two mutually prime integers, where m is the number of days it takes to have a nearly repeat orbit and n is the number of complete orbits in one day. We perform extensive analyses of GRACE Level-2 data over a period of eight years to show the variability in the orbital characteristics that are directly linked to the orbit resonances (via integers m and n). It turns out that during short repeat cycle resonances the stripes are amplified. Finally, to minimize the presence of stripes in Level-2 data products, it is recommended that orbits of future missions should be designed to avoid the critical m/n ratios while appropriately monitoring and adjusting them during the mission. For completed missions, or missions that are already active, force modelling the latitudinal low frequency disturbing potential may be a viable and most preferred approach to filtering.
Bora Flow Characteristics in a Complex Valley Environment
Authors: Bervida Marija , Stanič Samo , Močnik Griša , Wang Longlong , Bergant Klemen , Song Xiaoquan
Published: November 2021

This paper complements the existing studies of Bora flow properties in the Vipava valley with the study of Bora turbulence in a lower region of the troposphere. The turbulence characteristics of Bora flow were derived from high resolution Doppler wind lidar measurements during eight Bora wind episodes that occurred in November and December 2019. Based on the vertical profiles of wind velocity, from 80 to 180 m above the valley floor, the turbulence intensity related to all three spatial directions and the along-wind integral length scales related to three velocity components were evaluated and compared to the approximations given in international standards. The resulting turbulence characteristics of Bora flow in a deep mountain valley exhibited interesting behaviour, differing from the one expected and suggested by standards. The intensity of turbulence during Bora episodes was found to be quite strong, especially regarding the expected values for that particular category of terrain. The specific relationship between along-wind, lateral and vertical intensity was evaluated as well. The scales of turbulence in the along-wind direction were found to vary widely between different Bora episodes and were rather different from the approximations given by standards, with the most significant deviations observed for the along-wind length scale of the vertical velocity component. Finally, the periodicity of flow structures above the valley was assessed, yielding a wide range of possible periods between 1 and 10 min, thus confirming some of the previous observations from the studies of Bora in the Vipava valley.
The Effect of Attenuation from Fish on Passive Detection of Sound Sources in Ocean Waveguide Environments
Authors: Duane Daniel , Zhu Chenyang , Piavsky Felix , Godø Olav Rune , Makris Nicholas C.
Published: November 2021

Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range passive sensing of manmade vehicles, geophysical phenomena, and vocalizing marine life. The effect of attenuation from herring shoals on the Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) of surface vessels is investigated here, where concurrent wide-area active Ocean Acoustic Waveguide Remote Sensing (OAWRS) is used to confirm that herring shoals occluding the propagation path are responsible for measured reductions in ship radiated sound and corresponding detection losses. Reductions in the intensity of ship-radiated sound are predicted using a formulation for acoustic attenuation through inhomogeneities in an ocean waveguide that has been previously shown to be consistent with experimental measurements of attenuation from fish in active OAWRS transmissions. The predictions of the waveguide attenuation formulation are in agreement with measured reductions from attenuation, where the position, size, and population density of the fish groups are characterized using OAWRS imagery as well as in situ echosounder measurements of the specific shoals occluding the propagation path. Experimental measurements of attenuation presented here confirm previous theoretical predictions that common heuristic formulations employing free space scattering assumptions can be in significant error. Waveguide scattering and propagation theory is found to be necessary for accurate predictions.
Remote Sensing Scene Image Classification Based on Dense Fusion of Multi-level Features
Authors: Shi Cuiping , Zhang Xinlei , Sun Jingwei , Wang Liguo
Published: November 2021

For remote sensing scene image classification, many convolution neural networks improve the classification accuracy at the cost of the time and space complexity of the models. This leads to a slow running speed for the model and cannot realize a trade-off between the model accuracy and the model running speed. As the network deepens, it is difficult to extract the key features with a sample double branched structure, and it also leads to the loss of shallow features, which is unfavorable to the classification of remote sensing scene images. To solve this problem, we propose a dual branch multi-level feature dense fusion-based lightweight convolutional neural network (BMDF-LCNN). The network structure can fully extract the information of the current layer through 3 × 3 depthwise separable convolution and 1 × 1 standard convolution, identity branches, and fuse with the features extracted from the previous layer 1 × 1 standard convolution, thus avoiding the loss of shallow information due to network deepening. In addition, we propose a downsampling structure that is more suitable for extracting the shallow features of the network by using the pooled branch to downsample and the convolution branch to compensate for the pooled features. Experiments were carried out on four open and challenging remote sensing image scene data sets. The experimental results show that the proposed method has higher classification accuracy and lower model complexity than some state-of-the-art classification methods and realizes the trade-off between model accuracy and model running speed.
Synergistic Attention for Ship Instance Segmentation in SAR Images
Authors: Zhao Danpei , Zhu Chunbo , Qi Jing , Qi Xinhu , Su Zhenhua , Shi Zhenwei
Published: November 2021

This paper takes account of the fact that there is a lack of consideration for imaging methods and target characteristics of synthetic aperture radar (SAR) images among existing instance segmentation methods designed for optical images. Thus, we propose a method for SAR ship instance segmentation based on the synergistic attention mechanism which not only improves the performance of ship detection with multi-task branches but also provides pixel-level contours for subsequent applications such as orientation or category determination. The proposed method—SA R-CNN—presents a synergistic attention strategy at the image, semantic, and target level with the following module corresponding to the different stages in the whole process of the instance segmentation framework. The global attention module (GAM), semantic attention module (SAM), and anchor attention module (AAM) were constructed for feature extraction, feature fusion, and target location, respectively, for multi-scale ship targets under complex background conditions. Compared with several state-of-the-art methods, our method reached 68.7 AP in detection and 56.5 AP in segmentation on the HRSID dataset, and showed 91.5 AP in the detection task on the SSDD dataset.
Empirical Orthogonal Function Analysis and Modeling of Global Tropospheric Delay Spherical Harmonic Coefficients
Authors: Ma Yongchao , Liu Hang , Xu Guochang , Lu Zhiping
Published: November 2021

Based on the ERA-5 meteorological data from 2015 to 2019, we establish the global tropospheric delay spherical harmonic (SH) coefficients set called the SH_set and develop the global tropospheric delay SH coefficients empirical model called EGtrop using the empirical orthogonal function (EOF) method and periodic functions. We apply tropospheric delay derived from IGS stations not involved in modeling as reference data for validating the dataset, and statistical results indicate that the global mean Bias of the SH_set is 0.08 cm, while the average global root mean square error (RMSE) is 2.61 cm, which meets the requirements of the tropospheric delay model applied in the wide-area augmentation system (WAAS), indicating the feasibility of the product strategy. The tropospheric delay calculated with global sounding station and tropospheric delay products of IGS stations in 2020 are employed to validate the new product model. It is verified that the EGtrop model has high accuracy with Bias and RMSE of −0.25 cm and 3.79 cm, respectively, with respect to the sounding station, and with Bias and RMSE of 0.42 cm and 3.65 cm, respectively, with respect to IGS products. The EGtrop model is applicable not only at the global scale but also at the regional scale and exhibits the advantage of local enhancement.
Mapping Aquifer Storage Properties Using S-Wave Velocity and InSAR-Derived Surface Displacement in the Kumamoto Area, Southwest Japan
Authors: Mourad Mohamed , Tsuji Takeshi , Ikeda Tatsunori , Ishitsuka Kazuya , Senna Shigeki , Ide Kiyoshi
Published: November 2021

We present a novel approach to mapping the storage coefficient (Sk) from InSAR-derived surface deformation and S-wave velocity (Vs). We first constructed a 3D Vs model in the Kumamoto area, southwest Japan, by applying 3D empirical Bayesian kriging to the 1D Vs profiles estimated by the surface-wave analysis at 676 measured points. We also used the time series of InSAR deformation and groundwater-level data at 13 well sites covering April 2016 and December 2018 and estimated the Sk of the confined aquifer. The Sk estimated from InSAR, and well data ranged from ~0.03 to 2 × 10−3, with an average of 7.23 × 10−3, values typical for semi-confined and confined conditions. We found a clear relationship between the Sk and Vs at well locations, indicating that the compressibility of an aquifer is related to the stiffness or Vs. By applying the relationship to the 3D Vs model, we succeeded in mapping the Sk in an extensive area. Furthermore, the estimated Sk distribution correlates well with the hydrogeological setting: semi-confined conditions are predicted in the Kumamoto alluvial plain with a high Sk. Our approach is thus effective for estimating aquifer storage properties from Vs, even where limited groundwater-level data are available. Furthermore, we can estimate groundwater-level variation from the geodetic data.
Southwestern Atlantic Ocean Fronts Detected from Satellite-Derived SST and Chlorophyll
Authors: Wang Zhi , Chen Ge , Han Yong , Ma Chunyong , Lv Ming
Published: November 2021

The Southern Ocean front (SOF) is an important factor that affects the heat exchange and material transport of the Southern Ocean. In the past two decades, with the advancements in satellite remote-sensing technology, the study of the spatio-temporal variability of the Southern Ocean front has become a new hot topic. Nevertheless, the southwestern Atlantic, as an important part of the Southern Ocean, is poorly studied in this regard. Based on the 16-year (2004–2019) high-resolution satellite observations of sea surface temperature (SST) and 13-year (2007–2019) observations of chlorophyll (CHL), this study detected and analyzed the position and seasonal variation of the SOF in the southwestern Atlantic using a gradient-based frontal detection method. According to the experimental results, the thermal front (derived from the SST data) disappeared in winter due to the spatially uniform surface cooling, whereas the ocean color front (derived from the CHL data) existed without remarkable spatio-temporal changes. Furthermore, the exact position and seasonal variation of the SOF in the southwestern Atlantic are determined by comparing the paths of the two fronts. Since the formation of the Kuroshio front in the East China Sea (ECS) is similar to the SOF in the southwestern Atlantic, the seasonal distributions of the two fronts were compared. Apart from that, the Kuroshio thermal fronts were mostly distributed in winter and less in summer, while the Southern Ocean thermal fronts showed the opposite. These results indicated that the ocean current properties significantly influence the spatio-temporal variability of the front.
Modelling Permafrost Distribution in Western Himalaya Using Remote Sensing and Field Observations
Authors: Khan Md Ataullah Raza , Singh Shaktiman , Pandey Pratima , Bhardwaj Anshuman , Ali Sheikh Nawaz , Chaturvedi Vasudha , Ray Prashant Kumar Champati
Published: November 2021

The presence and extent of permafrost in the Himalaya, which is a vital component of the cryosphere, remains severely under-researched with its future climatic-driven trajectory only partly understood and the future consequences on high-altitude ecosystem tentatively sketched out. Previous studies and available permafrost maps for the Himalaya relied primarily upon the modelled meteorological inputs to further model the likelihood of permafrost. Here, as a maiden attempt, we have quantified the distribution of permafrost at 30 m grid-resolution in the Western Himalaya using observations from multisource satellite datasets for estimating input parameters, namely temperature, potential incoming solar radiation (PISR), slope, aspect and land use, and cover. The results have been compared to previous studies and have been validated through field investigations and geomorphological proxies associated with permafrost presence. A large part of the study area is barren land (~69%) due to its extremely resistive climate condition with ~62% of the total area having a mean annual air temperature of (MAAT) <1 °C. There is a high inter-annual variability indicated by varying standard deviation (1–3 °C) associated with MAAT with low standard deviation in southern part of the study area indicating low variations in areas with high temperatures and vice-versa. The majority of the study area is northerly (~36%) and southerly (~38%) oriented, receiving PISR between 1 and 2.5 MW/m2. The analysis of permafrost distribution using biennial mean air temperature (BMAT) for 2002-04 to 2018-20 suggests that the ~25% of the total study area has continuous permafrost, ~35% has discontinuous permafrost, ~1.5% has sporadic permafrost, and ~39% has no permafrost presence. The temporal analysis of permafrost distribution indicates a significant decrease in the permafrost cover in general and discontinuous permafrost in particular, from 2002-04 to 2018-20, with a loss of around 3% for the total area (~8340.48 km2). The present study will serve as an analogue for future permafrost studies to help understand the permafrost dynamics associated with the effects of the recent abrupt rise in temperature and change in precipitation pattern in the region.
Detection of Sleep-Disordered Breathing in Patients with Spinal Cord Injury Using a Smartphone
Authors: Castillo-Escario Yolanda , Kumru Hatice , Ferrer-Lluis Ignasi , Vidal Joan , Jané Raimon
Published: November 2021

Patients with spinal cord injury (SCI) have an increased risk of sleep-disordered breathing (SDB), which can lead to serious comorbidities and impact patients’ recovery and quality of life. However, sleep tests are rarely performed on SCI patients, given their multiple health needs and the cost and complexity of diagnostic equipment. The objective of this study was to use a novel smartphone system as a simple non-invasive tool to monitor SDB in SCI patients. We recorded pulse oximetry, acoustic, and accelerometer data using a smartphone during overnight tests in 19 SCI patients and 19 able-bodied controls. Then, we analyzed these signals with automatic algorithms to detect desaturation, apnea, and hypopnea events and monitor sleep position. The apnea–hypopnea index (AHI) was significantly higher in SCI patients than controls (25 ± 15 vs. 9 ± 7, p < 0.001). We found that 63% of SCI patients had moderate-to-severe SDB (AHI ≥ 15) in contrast to 21% of control subjects. Most SCI patients slept predominantly in supine position, but an increased occurrence of events in supine position was only observed for eight patients. This study highlights the problem of SDB in SCI and provides simple cost-effective sleep monitoring tools to facilitate the detection, understanding, and management of SDB in SCI patients.
Multi-Sensor Fault Diagnosis of Underwater Thruster Propeller Based on Deep Learning
Authors: Tsai Chia-Ming , Wang Chiao-Sheng , Chung Yu-Jen , Sun Yung-Da , Perng Jau-Woei
Published: November 2021

With the rapid development of unmanned surfaces and underwater vehicles, fault diagnoses for underwater thrusters are important to prevent sudden damage, which can cause huge losses. The propeller causes the most common type of thruster damage. Thus, it is important to monitor the propeller’s health reliably. This study proposes a fault diagnosis method for underwater thruster propellers. A deep convolutional neural network was proposed to monitor propeller conditions. A Hall element and hydrophone were used to obtain the current signal from the thruster and the sound signal in water, respectively. These raw data were fast Fourier transformed from the time domain to the frequency domain and used as the input to the neural network. The output of the neural network indicated the propeller’s health conditions. This study demonstrated the results of a single signal and the fusion of multiple signals in a neural network. The results showed that the multi-signal input had a higher accuracy than the one-signal input. With multi-signal inputs, training two types of signals with a separated neural network and then merging them at the end yielded the best results (99.88%), as compared to training two types of signals with a single neural network.
Can the AHCL System Be Used in T1D Patients with Borderline TDDI? A Case Report
Authors: Tekielak Anna , Seget Sebastian , Rusak Ewa , Jarosz-Chobot Przemysława
Published: November 2021

(1) Background: Intensive insulin therapy using continuous subcutaneous insulin infusion (CSII) with continuous real-time glucose monitoring (rt CGM) is the best option for patients with T1D. The recent introduction of a technology called Advanced Hybrid Closed Loop (AHCL) represents a new era in the treatment of type 1 diabetes, the next step towards better care, as well as improving the effectiveness and safety of therapy. The aim is to present the case of a T1D patient with a borderline total daily dose of insulin being treated with the Medtronic AHCL system in automatic mode. (2) Materials and Methods: A 9-year-old boy, from October 2020, with type 1 diabetes in remission was connected to the Minimed™ 780G (AHCL) system in accordance with the manufacturer’s recommendations (daily insulin dose > 8 units, age > 7). Records of the patient’s history were collected from visits to The Department of Children’s Diabetology, as well as from the Medtronic CareLink™ software and the DPV SWEET program from October 2020 to April 2021. (3) Results: The patient’s total daily insulin requirement decreased in the first 6 weeks after the AHCL was connected, which may reflect the remission phase (tight glycemic control with a healthy lifestyle). The lowest daily insulin requirement of 5.7 units was also recorded. In a three-month follow-up of the patient treated with AHCL, it was found that for almost 38% of the days the insulin dose was less than 8 IU. (4) Conclusions: The AHCL system allows safe and effective insulin therapy in automatic mode, as well as in patients with a lower daily insulin requirement. The AHCL system should be considered a good therapeutic option for patients from the onset of T1D, as well in the remission phase.