bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Printed Buccal Films for Prolonged-Release of Propranolol Hydrochloride: Development, Characterization and Bioavailability Prediction
Authors: Jovanović Marija , Petrović Miloš , Cvijić Sandra , Tomić Nataša , Stojanović Dušica , Ibrić Svetlana , Uskoković Petar
Published: December 2021

Gelatin-polyvinylpyrrolidone (PVP) and gelatin-poly(vinyl alcohol) (PVA) mucoadhesive buccal films loaded with propranolol hydrochloride (PRH) were prepared by semi-solid extrusion 3D printing. The aim of this study was to evaluate the effects of the synthetic polymers PVP and PVA on thermal and mechanical properties and drug release profiles of gelatin-based films. The Fourier-transform infrared spectroscopy showed that hydrogen bonding between gelatin and PVP formed during printing. In the other blend, neither the esterification of PVA nor gelatin occurred. Differential scanning calorimetry revealed the presence of partial helical structures. In line with these results, the mechanical properties and drug release profiles were different for each blend. Formulation with gelatin-PVP and PRH showed higher tensile strength, hardness, and adhesive strength but slower drug release than formulation with gelatin-PVA and PRH. The in silico population simulations indicated increased drug bioavailability and decreased inter-individual variations in the resulting pharmacokinetic profiles compared to immediate-release tablets. Moreover, the simulation results suggested that reduced PRH daily dosing can be achieved with prolonged-release buccal films, which improves patient compliance.
Spanish Spelt Wheat: From an Endangered Genetic Resource to a Trendy Crop
Authors: Alvarez Juan B.
Published: December 2021

Spelt wheat (Triticum aestivum L. ssp. spelta Thell.) is an ancient wheat that was widely cultivated in the past. This species derived from a cross between emmer wheat (T. turgidum spp. dicoccum Schrank em. Thell.) and Aegilops tauschii Coss. Its main origin was in the Fertile Crescent (Near East), with a secondary center of origin in Europe due to a second hybridization event between emmer and hexaploid wheat. This species has been neglected in most of Europe; however, the desire for more natural foods has driven a revival in interest. Iberian spelt is classified as a geographical group differing to the rest of European spelt. In this review, the particularities, genetic diversity and current situation of Spanish spelt, mainly for quality traits, are discussed.
Phytochemistry, Pharmacological Properties, and Recent Applications of Ficus benghalensis and Ficus religiosa
Authors: Murugesu Suganya , Selamat Jinap , Perumal Vikneswari
Published: December 2021

Ficus is one of the largest genera in the plant kingdom that belongs to the Moraceae family. This review aimed to summarize the medicinal uses, phytochemistry, and pharmacological actions of two major species from this genus, namely Ficus benghalensis and Ficus religiosa. These species can be found abundantly in most Asian countries, including Malaysia. The chemical analysis report has shown that Ficus species contained a wide range of phytoconstituents, including phenols, flavonoids, alkaloids, tannins, saponins, terpenoids, glycosides, sugar, protein, essential and volatile oils, and steroids. Existing studies on the pharmacological functions have revealed that the observed Ficus species possessed a broad range of biological properties, including antioxidants, antidiabetic, anti-inflammatory, anticancer, antitumor and antiproliferative, antimutagenic, antimicrobial, anti-helminthic, hepatoprotective, wound healing, anticoagulant, immunomodulatory activities, antistress, toxicity studies, and mosquitocidal effects. Apart from the plant parts and their extracts, the endophytes residing in these host plants were discussed as well. This study also includes the recent applications of the Ficus species and their plant parts, mainly in the nanotechnology field. Various search engines and databases were used to obtain the scientific findings, including Google Scholar, ScienceDirect, PMC, Research Gate, and Scopus. Overall, the review discusses the therapeutic potentials discovered in recent times and highlights the research gaps for prospective research work.
Grape Pomace Extracted Tannin for Green Synthesis of Silver Nanoparticles: Assessment of Their Antidiabetic, Antioxidant Potential and Antimicrobial Activity
Authors: Saratale Rijuta Ganesh , Saratale Ganesh Dattatraya , Ahn Somin , Shin Han-Seung
Published: December 2021

In nanoscience, the “green” synthesis approach has received great interest as an eco-friendly and sustainable method for the fabrication of a wide array of nanoparticles. The present study accounts for an expeditious technique for the synthesis of silver nanoparticles (AgNPs) utilizing fruit waste grape pomace extracted tannin. Grape pomace tannin (Ta) involved in the reduction and capping of AgNPs and leads to the formation of stable Ta-AgNPs. Various conditions were attempted to optimize the particle size and morphology of Ta-AgNPs which was further analyzed using various analytical tools for different characteristic motives. UV-visible spectroscopy showed a characteristic peak at 420 nm, indicating successful synthesis of AgNPs. Energy disperses spectroscopy (EDS) analysis proved the purity of the produced Ta-AgNPs and manifested a strong signal at −2.98 keV, while Fourier-transform infrared spectrophotometer (FTIR) spectra of the Ta-AgNPs displayed the existence of functional groups of tannin. Zeta potential measurements (−28.48 mV) showed that the Ta-AgNPs have reasonably good stability. High resolution transmission electron microscopy (HR-TEM) analysis confirmed the average dimension of the synthesized NPs was estimated about 15–20 nm. Ta-AgNPs potentials were confirmed by in vitro antidiabetic activity to constrain carbohydrate digesting enzymes, mainly α-amylase and α-glucosidase, with a definite concentration of sample displaying 50% inhibition (IC50), which is about 43.94 and 48.5 μg/mL, respectively. Synthesized Ta-AgNPs exhibited significant antioxidant potential with respect to its 2,2′-azino-bis(3-ethylbenzothi-azoline-6-sulfonic acid) (ABTS) (IC50 of 40.98 µg/mL) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50 of 53.98 µg/mL) free radical scavenging activities. Ta-AgNPs exhibited extraordinary antibacterial activity against selected pathogenic strains and showed comparable antimicrobial index against ampicillin as a positive control.
Pyrolytic Behavior of Polyvinyl Chloride: Kinetics, Mechanisms, Thermodynamics, and Artificial Neural Network Application
Authors: Al-Yaari Mohammed , Dubdub Ibrahim
Published: December 2021

Pyrolysis of waste polyvinyl chloride (PVC) is considered a promising and highly efficient treatment method. This work aims to investigate the kinetics, and thermodynamics of the process of PVC pyrolysis. Thermogravimetry of PVC pyrolysis at three heating rates (5, 10, and 20 K/min) showed two reaction stages covering the temperature ranges of 490–675 K, and 675–825 K, respectively. Three integral isoconversional models, namely Flynn-Wall-Qzawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink, were used to obtain the activation energy (Ea), and pre-exponential factor (A) of the PVC pyrolysis. On the other hand, the Coats-Redfern non-isoconversional model was used to determine the most appropriate solid-state reaction mechanism/s for both stages. Values of Ea, and A, obtained by the isoconversional models, were very close and the average values were, for stage I: Ea = 75 kJ/mol, A = 1.81 × 106 min−1; for stage II: Ea = 140 kJ/mol, A = 4.84 × 109 min−1. In addition, while the recommended mechanism of the first stage reaction was P2, F3 was the most suitable mechanism for the reaction of stage II. The appropriateness of the mechanisms was confirmed by the compensation effect. Thermodynamic study of the process of PVC pyrolysis confirmed that both reactions are endothermic and nonspontaneous with promising production of bioenergy. Furthermore, a highly efficient artificial neural network (ANN) model has been developed to predict the weight left % during the PVC pyrolysis as a function of the temperature and heating rate. The 2-10-10-1 topology with TANSIG-LOGSIG transfer function and feed-forward back-propagation characteristics was used.
Thiol-Functional Polymer Nanoparticles via Aerosol Photopolymerization
Authors: Suvarli Narmin , Perner-Nochta Iris , Hubbuch Jürgen , Wörner Michael
Published: December 2021

Spherical, individual polymer nanoparticles with functional –SH groups were synthesized via aerosol photopolymerization (APP) employing radically initiated thiol-ene chemistry. A series of various thiol and alkene monomer combinations were investigated based on di-, tri-, and tetrafunctional thiols with difunctional allyl and vinyl ethers, and di- and trifunctional acrylates. Only thiol and alkene monomer combinations able to build cross-linked poly(thio-ether) networks were compatible with APP, which requires fast polymerization of the generated droplet aerosol during the photoreactor passage within a residence time of half-minute. Higher monomer functionalities and equal overall stoichiometry of functional groups resulted in the best nanoparticles being spherical and individual, proven by scanning electron microscopy (SEM). The presence of reactive –SH groups in the synthesized nanoparticles as a basis for post-polymerization modifications was verified by Ellman’s test.
3D-Printed Coaxial Hydrogel Patches with Mussel-Inspired Elements for Prolonged Release of Gemcitabine
Authors: Talebian Sepehr , Shim In Kyong , Foroughi Javad , Orive Gorka , Vine Kara L. , Kim Song Cheol , Wallace Gordon G.
Published: December 2021

With the aim of fabricating drug-loaded implantable patches, a 3D printing technique was employed to produce novel coaxial hydrogel patches. The core-section of these patches contained a dopamine-modified methacrylated alginate hydrogel loaded with a chemotherapeutic drug (Gemcitabine), while their shell section was solely comprised of a methacrylated alginate hydrogel. Subsequently, these patches were further modified with CaCO3 cross linker and a polylactic acid (PLA) coating to facilitate prolonged release of the drug. Consequently, the results showed that addition of CaCO3 to the formula enhanced the mechanical properties of the patches and significantly reduced their swelling ratio as compared to that for patches without CaCO3. Furthermore, addition of PLA coating to CaCO3-containing patches has further reduced their swelling ratio, which then significantly slowed down the release of Gemcitabine, to a point where 4-layered patches could release the drug over a period of 7 days in vitro. Remarkably, it was shown that 3-layered and 4-layered Gemcitabine loaded patches were successful in inhibiting pancreatic cancer cell growth for a period of 14 days when tested in vitro. Lastly, in vivo experiments showed that gemcitabine-loaded 4-layered patches were capable of reducing the tumor growth rate and caused no severe toxicity when tested in mice. Altogether, 3D printed hydrogel patches might be used as biocompatible implants for local delivery of drugs to diseased site, to either shrink the tumor or to prevent the tumor recurrence after resection.
Collagen-Based Nanofibers for Skin Regeneration and Wound Dressing Applications
Authors: Mbese Zintle , Alven Sibusiso , Aderibigbe Blessing Atim
Published: December 2021

Skin regeneration after an injury is very vital, but this process can be impeded by several factors. Regenerative medicine is a developing biomedical field with the potential to decrease the need for an organ transplant. Wound management is challenging, particularly for chronic injuries, despite the availability of various types of wound dressing scaffolds in the market. Some of the wound dressings that are in clinical practice have various drawbacks such as poor antibacterial and antioxidant efficacy, poor mechanical properties, inability to absorb excess wound exudates, require frequent change of dressing and fails to offer a suitable moist environment to accelerate the wound healing process. Collagen is a biopolymer and a major constituent of the extracellular matrix (ECM), making it an interesting polymer for the development of wound dressings. Collagen-based nanofibers have demonstrated interesting properties that are advantageous both in the arena of skin regeneration and wound dressings, such as low antigenicity, good biocompatibility, hemostatic properties, capability to promote cellular proliferation and adhesion, and non-toxicity. Hence, this review will discuss the outcomes of collagen-based nanofibers reported from the series of preclinical trials of skin regeneration and wound healing.
Composite as a Material of the Future in the Era of Green Deal Implementation Strategies
Authors: Czapla Aleksander , Ganesapillai Mahesh , Drewnowski Jakub
Published: December 2021

Composite materials have become synonymous with modernity, desired in nearly every aspect of our daily lives, from simple everyday objects to sanitary facilities, pipelines, the construction of modern sewer networks, their renovation, water supply, and storage reservoirs, to complex structures—automotive, planes, and space science. Composites have seen a considerable rise in attention owing to their characteristics, durability, strength, reduced energy usage during the manufacturing process, and decreased transportation costs. Composite materials consistently outperform steel, cast iron, and concrete in terms of CO2 emissions. Additionally, these materials have a long service life of about 150 years or more and are corrosion-resistant. Today, continued sustainable development is contingent upon access to safe drinking water and the availability of its resources and modes of conveyance. As a result, composite pipes have considerable potential due to their very low flow rate, which directly affects the prices of drinking water pumping and irrigation systems. However, there are also certain disadvantages associated with fibre-reinforced composites, such as easy surface damage, low heat resistance (up to 220 °C), long product forming time, and high cost of the material. Additionally, the product’s initial high durability and extended life cycle, coupled with high abrasion resistance, anisotropic strength, and stiffness in the final phase, prove to be unfavourable since composite material cannot be rapidly reintroduced into the manufacturing cycle. However, its disposal requires a negligible amount of energy. The article discusses the various composite materials available, their applications, and the potential for further developing their manufacturing technology toward nanocomposites and composites of natural origin that are readily biodegradable at the end of their service life; dubbed “green composites”. The study’s findings are unequivocal: this class of composite materials warrants further investigation in the future since they align perfectly with the concept of sustainable economic growth and Green Deal implementation.
Adsorption and Reaction Mechanisms of Direct Palladium Synthesis by ALD Using Pd(hfac)2 and Ozone on Si (100) Surface
Authors: Cheng Chunyu , Zou Yiming , Li Jiahui , Ong Amanda Jiamin , Goei Ronn , Huang Jingfeng , Li Shuzhou , Tok Alfred Iing Yoong
Published: December 2021

Palladium nanoparticles made by atomic layer deposition (ALD) normally involve formaldehyde or H2 as a reducing agent. Since formaldehyde is toxic and H2 is explosive, it is advantageous to remove this reducing step during the fabrication of palladium metal by ALD. In this work we have successfully used Pd(hfac)2 and ozone directly to prepare palladium nanoparticles, without the use of reducing or annealing agents. Density functional theory (DFT) was employed to explore the reaction mechanisms of palladium metal formation in this process. DFT results show that Pd(hfac)2 dissociatively chemisorbed to form Pd(hfac)* and hfac* on the Si (100) surface. Subsequently, an O atom of the ozone could cleave the C–C bond of Pd(hfac)* to form Pd* with a low activation barrier of 0.46 eV. An O atom of the ozone could also be inserted into the hfac* to form Pd(hfac-O)* with a lower activation barrier of 0.29 eV. With more ozone, the C–C bond of Pd(hfac-O)* could be broken to produce Pd* with an activation barrier of 0.42 eV. The ozone could also chemisorb on the Pd atom of Pd(hfac-O)* to form O3-Pd(hfac-O)*, which could separate into O-Pd(hfac-O)* with a high activation barrier of 0.83 eV. Besides, the activation barrier was 0.64 eV for Pd* that was directly oxidized to PdOx by ozone. Based on activation barriers from DFT calculations, it was possible to prepare palladium without reducing steps when ALD conditions were carefully controlled, especially the ozone parameters, as shown by our experimental results. The mechanisms of this approach could be used to prepare other noble metals by ALD without reducing/annealing agents.
Art and Influence, Presence and Navigation in Southern African Forager Landscapes
Authors: Challis Sam , Skinner Andrew
Published: December 2021

With earlier origins and a rebirth in the late 1990s, the New Animisms and the precipitate ‘ontological turn’ have now been in full swing since the mid-2000s. They make a valuable contribution to the interpretation of the rock arts of numerous societies, particularly in their finding that in animist societies, there is little distinction between nature and culture, religious belief and practicality, the sacred and the profane. In the process, a problem of perspective arises: the perspectives of such societies, and the analogical sources that illuminate them, diverge in more foundational terms from Western perspectives than is often accounted for. This is why archaeologists of religion need to be anthropologists of the wider world, to recognise where animistic and shamanistic ontologies are represented, and perhaps where there is reason to look closely at how religious systems are used to imply Cartesian separations of nature and culture, religious and mundane, human/person and animal/non-person, and where these dichotomies may obscure other forms of being-in-the-world. Inspired by Bird-David, Descola, Hallowell, Ingold, Vieiros de Castro, and Willerslev, and acting through the lens of navigation in a populated, enculturated, and multinatural world, this contribution locates southern African shamanic expressions of rock art within broader contexts of shamanisms that are animist.
An Investigation into Current Sand Control Methodologies Taking into Account Geomechanical, Field and Laboratory Data Analysis
Authors: Tananykhin Dmitry , Korolev Maxim , Stecyuk Ilya , Grigorev Maxim
Published: December 2021

Sand production is one of the major issues in the development of reservoirs in poorly cemented rocks. Geomechanical modeling gives us an opportunity to calculate the reservoir stress state, a major parameter that determines the stable pressure required in the bottomhole formation zone to prevent sand production, decrease the likelihood of a well collapse and address other important challenges. Field data regarding the influence of water cut, bottomhole pressure and fluid flow rate on the amount of sand produced was compiled and analyzed. Geomechanical stress-state models and Llade’s criterion were constructed and applied to confirm the high likelihood of sanding in future wells using the Mohr–Coulomb and Mogi–Coulomb prototypes. In many applications, the destruction of the bottomhole zone cannot be solved using well mode operations. In such cases, it is necessary to perform sand retention or prepack tests in order to choose the most appropriate technology. The authors of this paper conducted a series of laboratory prepack tests and it was found that sanding is quite a dynamic process and that the most significant sand production occurs in the early stages of well operation. With time, the amount of produced sand decreases greatly—up to 20 times following the production of 6 pore volumes. Finally, the authors formulated a methodological approach to sand-free oil production.
The Assessment of Hydrogeosites in the Fann Mountains, Tajikistan as a Basis for Sustainable Tourism
Authors: Pukowiec-Kurda Katarzyna , Rahmonov Oimahmad , Sobala Michał , Myga-Piątek Urszula
Published: December 2021

Despite the fact that the Fann Mountains are among the most popular tourist destinations in Tajikistan, they are still in the first stage of tourism development. This represents a great opportunity for the implementation of the principles of sustainable tourism, which will avoid the mistakes associated with the uncontrolled tourism development currently observed in other mountain areas of the world. The aim of this article is to demonstrate, using the example of the Fann Mountains, how hydrogeosites in mountain areas can be valorised for the needs of cognitive tourism. The valorisation methods used in previous research to this point have focused on the evaluation of the objects themselves. This study additionally takes into account features of the surroundings of hydrogeostations, such as the visibility range, the vertical development of the view, and the diversity of the landscape. The conducted value assessments of the sites and their surroundings show that in both internal and external assessments the highest values were achieved by lakes and wetlands. This means that the evaluation of the surroundings has a strong influence on the results obtained and the choice of hydrogeotourism attractions.
Multimodal Data and Multiscale Kernel-Based Multistream CNN for Fine Classification of a Complex Surface-Mined Area
Authors: Qian Mingjie , Sun Song , Li Xianju
Published: December 2021

Fine land cover classification (FLCC) of complex landscapes is a popular and challenging task in the remote sensing community. In complex surface-mined areas (CSMAs), researchers have conducted FLCC using traditional machine learning methods and deep learning algorithms. However, convolutional neural network (CNN) algorithms that may be useful for FLCC of CSMAs have not been fully investigated. This study proposes a multimodal remote sensing data and multiscale kernel-based multistream CNN (3M-CNN) model. Experiments based on two ZiYuan-3 (ZY-3) satellite imageries of different times and seasons were conducted in Wuhan, China. The 3M-CNN model had three main features: (1) multimodal data-based multistream CNNs, i.e., using ZY-3 imagery-derived true color, false color, and digital elevation model data to form three CNNs; (2) multisize neighbors, i.e., using different neighbors of optical and topographic data as inputs; and (3) multiscale convolution flows revised from an inception module for optical and topographic data. Results showed that the proposed 3M-CNN model achieved excellent overall accuracies on two different images, and outperformed other comparative models. In particular, the 3M-CNN model yielded obvious better visual performances. In general, the proposed process was beneficial for the FLCC of complex landscape areas.
Long-Term Gully Erosion and Its Response to Human Intervention in the Tableland Region of the Chinese Loess Plateau
Authors: Wang Jiaxi , Zhang Yan , Deng Jiayong , Yu Shuangwu , Zhao Yiyang
Published: December 2021

The gully erosion process is influenced by both natural conditions and human activities on the tableland region, the Chinese Loess Plateau, which is a densely populated agricultural area with unique topography. For the purpose of assessing long-term gully growth rates, the influencing factors and potential of gully growth, KH-4B satellite images, Quickbird-2 images, and unmanned aerial vehicle (UAV) images were used to assess gully erosion from 1969 to 2019. The effects of runoff, topography and human activities were analyzed with information derived from historical and present images. Ninety-five investigated gullies were classified into four types: 45 growing, 25 stable, 21 infilled and four excavated gullies. The rates (RA) of 45 growing gullies ranged from 0.50 to 20.94 m2·yr−1, with an average of 5.66 m2·yr−1 from 1969 to 2010. The present drainage area, local slope, average drainage slope, annual runoff, and ratio of the terraced area were all significantly different between the stable and growing gullies. The long-term gully growth rate could be estimated using a nonlinear regression model with annual runoff (Qa) and the slope of the drainage area (Sd) as predictors (RA = 0.301Qa0.562Sd, R2 = 0.530). Based on the Sg-A and Sg-Qa relationship that was used to reveal the threshold conditions for gully growth, all growing gullies still have the potential to keep growing, but soil and water conservation measures, including terraces, could change the threshold condition by reducing the effective drainage area. The results of this study could be helpful for preventing further gully erosion by dealing with gullies far above the threshold line.
Climate-Based Regionalization and Inclusion of Spectral Indices for Enhancing Transboundary Land-Use/Cover Classification Using Deep Learning and Machine Learning
Authors: Kavhu Blessing , Mashimbye Zama Eric , Luvuno Linda
Published: December 2021

Accurate land use and cover data are essential for effective land-use planning, hydrological modeling, and policy development. Since the Okavango Delta is a transboundary Ramsar site, managing natural resources within the Okavango Basin is undoubtedly a complex issue. It is often difficult to accurately map land use and cover using remote sensing in heterogeneous landscapes. This study investigates the combined value of climate-based regionalization and integration of spectral bands with spectral indices to enhance the accuracy of multi-temporal land use/cover classification using deep learning and machine learning approaches. Two experiments were set up, the first entailing the integration of spectral bands with spectral indices and the second involving the combined integration of spectral indices and climate-based regionalization based on Koppen–Geiger climate zones. Landsat 5 TM and Landsat 8 OLI images, machine learning classifiers (random forest and extreme gradient boosting), and deep learning (neural network and deep neural network) classifiers were used in this study. Supervised classification using a total of 5140 samples was conducted for the years 1996, 2004, 2013, and 2020. Average overall accuracy and Kappa coefficients were used to validate the results. The study found that the integration of spectral bands with indices improves the accuracy of land use/cover classification using machine learning and deep learning. Post-feature selection combinations yield higher accuracies in comparison to combinations of bands and indices. A combined integration of spectral indices with bands and climate-based regionalization did not significantly improve the accuracy of land use/cover classification consistently for all the classifiers (p < 0.05). However, post-feature selection combinations and climate-based regionalization significantly improved the accuracy for all classifiers investigated in this study. Findings of this study will improve the reliability of land use/cover monitoring in complex heterogeneous TDBs.
Understanding the Impact of Vertical Canopy Position on Leaf Spectra and Traits in an Evergreen Broadleaved Forest
Authors: Yu Fangyuan , Gara Tawanda W. , Lian Juyu , Ye Wanhui , Shen Jian , Wang Tiejun , Wu Zhifeng , Wang Junjie
Published: December 2021

Little attention has been paid to the impact of vertical canopy position on the leaf spectral properties of tall trees, and few studies have explored the ability of leaf spectra to characterize the variation of leaf traits across different canopy positions. Using a tower crane, we collected leaf samples from three canopy layers (lower, middle, and upper) and measured eight leaf traits (equivalent water thickness, specific leaf area, leaf carbon content, leaf nitrogen content, leaf phosphorus content, leaf chlorophyll content, flavonoid, and nitrogen balance index) in a subtropical evergreen broadleaved forest. We evaluated the variability of leaf traits and leaf spectral properties, as well as the ability of leaf spectra to track the variation of leaf traits among three canopy layers for six species within the entire reflectance spectrum. The results showed that the eight leaf traits that were moderately or highly correlated with each other showed significant differences along the vertical canopy profile. The three canopy layers of leaf spectra showed contrasting patterns for light-demanding (Castanopsis chinensis, Castanopsis fissa, Schima superba, and Machilus chinensis) and shade-tolerant species (Cryptocarya chinensis and Cryptocarya concinna) along the vertical canopy profile. The spectra at the lower and upper canopy layers were more sensitive than the middle layer for tracking the variation of leaf chlorophyll and flavonoid content. Our results revealed that it is important to choose an appropriate canopy layer for the field sampling of tall trees, and we suggest that flavonoid is an important leaf trait that can be used for mapping and monitoring plant growth with hyperspectral remote sensing.
An Overview of Neural Network Methods for Predicting Uncertainty in Atmospheric Remote Sensing
Authors: Doicu Adrian , Doicu Alexandru , Efremenko Dmitry S. , Loyola Diego , Trautmann Thomas
Published: December 2021

In this paper, we present neural network methods for predicting uncertainty in atmospheric remote sensing. These include methods for solving the direct and the inverse problem in a Bayesian framework. In the first case, a method based on a neural network for simulating the radiative transfer model and a Bayesian approach for solving the inverse problem is proposed. In the second case, (i) a neural network, in which the output is the convolution of the output for a noise-free input with the input noise distribution; and (ii) a Bayesian deep learning framework that predicts input aleatoric and model uncertainties, are designed. In addition, a neural network that uses assumed density filtering and interval arithmetic to compute uncertainty is employed for testing purposes. The accuracy and the precision of the methods are analyzed by considering the retrieval of cloud parameters from radiances measured by the Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR).
A Comprehensive Study of Anomaly Detection Schemes in IoT Networks Using Machine Learning Algorithms
Authors: Diro Abebe , Chilamkurti Naveen , Nguyen Van-Doan , Heyne Will
Published: December 2021

The Internet of Things (IoT) consists of a massive number of smart devices capable of data collection, storage, processing, and communication. The adoption of the IoT has brought about tremendous innovation opportunities in industries, homes, the environment, and businesses. However, the inherent vulnerabilities of the IoT have sparked concerns for wide adoption and applications. Unlike traditional information technology (I.T.) systems, the IoT environment is challenging to secure due to resource constraints, heterogeneity, and distributed nature of the smart devices. This makes it impossible to apply host-based prevention mechanisms such as anti-malware and anti-virus. These challenges and the nature of IoT applications call for a monitoring system such as anomaly detection both at device and network levels beyond the organisational boundary. This suggests an anomaly detection system is strongly positioned to secure IoT devices better than any other security mechanism. In this paper, we aim to provide an in-depth review of existing works in developing anomaly detection solutions using machine learning for protecting an IoT system. We also indicate that blockchain-based anomaly detection systems can collaboratively learn effective machine learning models to detect anomalies.
The Effect of Implanted Functional Electrical Stimulation on Gait Performance in Stroke Survivors: A Systematic Review
Authors: Kang Gu Eon , Frederick Rebecca , Nunley Brandon , Lavery Lawrence , Dhaher Yasin , Najafi Bijan , Cogan Stuart
Published: December 2021

The emerging literature suggests that implantable functional electrical stimulation may improve gait performance in stroke survivors. However, there is no review providing the possible therapeutic effects of implanted functional electrical stimulation on gait performance in stroke survivors. We performed a web-based, systematic paper search using PubMed, the Cochrane Library, and EMBASE. We limited the search results to human subjects and papers published in peer-reviewed journals in English. We did not restrict demographic or clinical characteristics. We included 10 papers in the current systematic review. Across all included studies, we found preliminary evidence of the potential therapeutic effects of functional electrical stimulation on walking endurance, walking speed, ankle mobility, and push-off force in stroke survivors. However, due to the heterogeneity between the included studies, small sample size, and lack of randomized controlled trials, more studies are critically needed to confirm whether implanted functional electrical stimulation can improve gait performance in stroke survivors.
A Three-Dimensional Integrated Non-Linear Coordinate Control Framework for Combined Yaw- and Roll-Stability Control during Tyre Blow-Out
Authors: Li Boyuan , Huang Chao , Wu Yang , Zhang Bangji , Du Haiping
Published: December 2021

A tyre blow-out can greatly affect vehicle stability and cause serious accidents. In the literature, however, studies on comprehensive three-dimensional vehicle dynamics modelling and stability control strategies in the event of a sudden tyre blow-out are seriously lacking. In this study, a comprehensive 14 degrees-of-freedom (DOF) vehicle dynamics model is first proposed to describe the vehicle yaw-plane and roll-plane dynamics performance after a tyre blow-out. Then, based on the proposed 14 DOF dynamics model, an integrated control framework for a combined yaw plane and roll-plane stability control is presented. This integrated control framework consists of a vehicle state predictor, an upper-level control mode supervisor and a lower-level 14 DOF model predictive controller (MPC). The state predictor is designed to predict the vehicle’s future states, and the upper-level control mode supervisor can use these future states to determine a suitable control mode. After that, based on the selected control mode, the lower-level MPC can control the individual driving actuator to achieve the combined yaw plane and roll plane control. Finally, a series of simulation tests are conducted to verify the effectiveness of the proposed control strategy.
Piezoelectric Energy Harvesting towards Self-Powered Internet of Things (IoT) Sensors in Smart Cities
Authors: Izadgoshasb Iman
Published: December 2021

Information and communication technologies (ICT) are major features of smart cities. Smart sensing devices will benefit from 5 G and the Internet of Things, which will enable them to communicate in a safe and timely manner. However, the need for sustainable power sources and self-powered active sensing devices will continue to be a major issue in this sector. Since their discovery, piezoelectric energy harvesters have demonstrated a significant ability to power wireless sensor nodes, and their application in a wide range of systems, including intelligent transportation, smart healthcare, human-machine interfaces, and security systems, has been systematically investigated. Piezoelectric energy-harvesting systems are promising candidates not only for sustainably powering wireless sensor nodes but also for the development of intelligent and active self-powered sensors with a wide range of applications. In this paper, the various applications of piezoelectric energy harvesters in powering Internet of Things sensors and devices in smart cities are discussed and reviewed.
The Application of Low-Frequency Transition in the Assessment of the Second-Order Zeeman Frequency Shift
Authors: Bai Yang , Wang Xinliang , Shi Junru , Yang Fan , Ruan Jun , Dong Ruifang , Zhang Shougang
Published: December 2021

Second-order Zeeman frequency shift is one of the major systematic factors affecting the frequency uncertainty performance of cesium atomic fountain clock. Second-order Zeeman frequency shift is calculated by experimentally measuring the central frequency of the (1,1) or (−1,−1) magnetically sensitive Ramsey transition. The low-frequency transition method can be used to measure the magnetic field strength and to predict the central fringe of (1,1) or (−1,−1) magnetically sensitive Ramsey transition. In this paper, we deduce the formula for magnetic field measurement using the low-frequency transition method and measured the magnetic field distribution of 4 cm inside the Ramsey cavity and 32 cm along the flight region experimentally. The result shows that the magnetic field fluctuation is less than 1 nT. The influence of low-frequency pulse signal duration on the accuracy of magnetic field measurement is studied and the optimal low-frequency pulse signal duration is determined. The central fringe of (−1,−1) magnetically sensitive Ramsey transition can be predicted by using a numerical integrating of the magnetic field “map”. Comparing the predicted central fringe with that identified by Ramsey method, the frequency difference between these two is, at most, a fringe width of 0.3. We apply the experimentally measured central frequency of the (−1,−1) Ramsey transition to the Breit-Rabi formula, and the second-order Zeeman frequency shift is calculated as 131.03 × 10−15, with the uncertainty of 0.10 × 10−15.
Role of the Universities as Drivers of Social Innovation
Authors: Puente Cristina , Fabra María Eugenia , Mason Cindy , Puente-Rueda Cristina , Sáenz-Nuño Maria Ana , Viñuales Ramiro
Published: December 2021

The role of universities as drivers of good practices and learning has changed radically in recent years. The strategic plan of the Comillas Pontifical University establishes the obligation of a learning and service subject in all degree programs as a way to put what has been learned during the university years at the service of society and as a vehicle for promoting the Sustainable Development Goals set by the 2030 Agenda. In this article we will present the theoretical framework on which the project has been developed, including the university context in which it fits, to analyze the process of design and implementation of a service-learning course in engineering degrees, selecting as case studies two examples of projects in which the social impact was high. As conclusions we will present the strengths and weaknesses of the implementation process, as well as the students’ learning based on their experiences.
Analyses of the Attitudes of Agricultural Holdings on the Development of Agritourism and the Impacts on the Economy, Society and Environment of Serbia
Authors: Ćirić Miloš , Tešanović Dragan , Kalenjuk Pivarski Bojana , Ćirić Ivana , Banjac Maja , Radivojević Goran , Grubor Biljana , Tošić Predrag , Simović Olivera , Šmugović Stefan
Published: December 2021

Agritourism as a special type of tourist migration is a very important link in the diversification of rural areas, connecting the geography, culture, tradition, and gastronomy of the local population, and placing products and services through the hospitality and tourism market. Thanks to this form of tourism, underdeveloped places are gaining in importance and attracting the attention of visitors who are oriented towards natural things, which in turn contributes to a better economic situation of the locality and the population. This paper aims to examine the attitudes of farm owners in the Republic of Serbia toward the impact of agritourism on the economy, living environment, social life, and culture. The data were collected by surveying the owners of agricultural holdings in the territory of the Republic of Serbia and statistically processed using factor analysis, descriptive statistics, and linear regression. Based on the obtained results, it has been established that the owners of agricultural farms are interested in the development of agritourism, and that their positive perception of the impact that agritourism has on the living environment and economy greatly contributes to that. To a lesser extent, a positive attitude was noted toward the importance of agrotourism for the local community and locals, where the positive aspects of agritourism were the education of visitors on agriculture, promotion of the local culture, agricultural and gastronomic products, and sustainable development and investment in infrastructure.
A Systematic Literature Review for the Recycling and Reuse of Wasted Clothing
Authors: Xie Xiufen , Hong Yan , Zeng Xianyi , Dai Xiaoqun , Wagner Melissa
Published: December 2021

With the growing frequency and quantity of clothing purchases, the elimination rate of waste clothing is increasing. Many researchers have contributed to the topic of the recycling and reuse of waste clothing, and therefore many related literature reviews are emerging. The current reviews only focus on waste textile recycling and waste-clothing life-cycle evaluation. The topic of waste-clothing recycling itself is ignored. In this article, we propose a systematic review of the recycling and reuse of wasted clothes. Firstly, we summarize the existing methods of waste-clothing collection and recycling and the related recycling technology, and discuss their advantages and disadvantages. The involved literatures are journal articles, book chapters, and conference papers selected from Google Scholar and Web of Science. Citespace software, as a literature visualization tool is used for the analysis. Based on this review, the low efficiency of waste-clothes recycling can be attributed to poor organization from a management aspect. From a consumer perspective, because of the differences in understanding among consumers about waste-clothing recycling, the existing clothing-recycling system cannot be fully utilized. The results of this review provide reference for further research on waste-clothing recycling, and make suggestions for the relevant governmental/industrial development strategies.
Bearing Capacity of Volcanic Pyroclasts Using the Discontinuity Layout Optimization Method
Authors: Galindo Rubén , Millán Miguel Ángel , Hernández-Gutiérrez Luis E. , Olalla Marañón Claudio , Patiño Hernán
Published: December 2021

The failure criterion of low-density volcanic rocks differs radically from that of conventional rocks by manifesting collapse under isotropic stress. In this way, the shapes of the failure model do not reveal a continuously increasing growth of deviating stress with the isotropic stress, but they reach a maximum value, after which they decrease until they vanish under the isotropic collapse pressure. As a consequence, engineering applications require the implementation of numerical codes and the resolution of associated numerical difficulties. This article presents the problem of the bearing capacity of a foundation on a low-density volcanic rock using the DLO (discontinuity layout optimization) numerical method. The analysis of results shows the ability of the DLO method to solve the numerical difficulties associated with the complex failure criteria, so that the convergence and stability of the solution can be achieved without generating high computational costs. Additionally, a discussion of the DLO results is also presented, demonstrating forms of failure on the ground following the real collapses in these volcanic materials. In addition, numerical validation was performed with the finite difference method, using FLAC, and with an analytical method using simplified configurations, obtaining good contrast results, with the DLO method performing better. In this way, an adequate and reliable resolution technique is provided to face the problem of bearing capacity in low-density volcanic rocks, overcoming limitations referred to in the technical literature regarding the difficulty of treating highly non-linear and non-monotonic numerical criteria, which allows the introduction of isotropic collapse failure.
Urban Fabrics to Eco-Friendly Blue–Green for Urban Wetland Development
Authors: Rojas Quezada Carolina , Jorquera Felipe
Published: December 2021

In an urbanized world, the sustainability of cities will depend on their form and urban structure. In this sense, fabrics that are compact, dense, green, and suitable for non-motorized transport methods are more environmentally efficient. For the purpose of contributing new tools to the design, urban planning, and sustainability of nature in residential areas, this study characterizes the urban fabrics of six urban wetlands in the Latin American city of Concepción (Chile), which is known for its blue–green spaces. In a wetland city, we model urban patterns through spatial relationship using a statistical regression model (OLS—ordinary least squares) with the urban variables of density, distance, population, housing, highways, green areas, and building permits. Concepción shows predominantly low- to medium-density fabrics, and it is not integrated with the urban wetlands. In fact, it was observed that the residential areas do not take advantage of the blue–green spaces and that the urban fabrics do not favor proximity, with a transportation network that promotes the use of cars, leading to the wetlands being inaccessible and fragmented. However, as they are still surrounded by open spaces with abundant vegetation, there are highly feasible opportunities for the future development of blue–green infrastructure.
Geopolitical-Risk and Economic Policy—Uncertainty Impacts on Tourist Flows from Neighboring Countries: A Wavelet Analysis
Authors: Kazakova Alisa , Kim Insin
Published: December 2021

This paper investigates the nexus of geopolitical risks (GPRs), economic policy uncertainty (EPU), and tourist arrivals in South Korea. Specifically, this research examines whether arrivals from neighboring tourism source countries (i.e., China and Japan) are influenced by geopolitical events and economic volatilities in South Korea. To establish the research purpose, we investigated the relationships among GPRs, EPU, and tourism demand by using monthly data from January 2003 to November 2019. Additionally, innovative techniques (continuous wavelets, wavelet coherency, and wavelet phase difference) were employed, which allow the decomposition of time series considering different time and frequency components. The results demonstrate inconsistent and heterogeneous co-movements between variables that are localized across different time periods and frequencies. In addition, we detected several significant coherencies that prove the important role of GPR and EPU in explaining changes in the numbers of tourists arriving in South Korea from China and Japan. In terms of time domain, negative and positive correlations in tourism demand were detected, meaning that economic and geopolitical shocks may not always lead to negative consequences. From the frequency domain, the causal effects of GPR mostly appear to have short- to mid-run implications, with almost no relationship in the low-frequency band, whereas EPU holds a heterogeneous influence varying short-term to long-term, including higher to lower frequencies. Results show the resilience of the tourism industry against the transient effects of economic and geopolitical shocks. Tourists become adversely affected by external events such as geopolitical risks and economic uncertainties, but the impact is not consistent over time for tourists from countries neighboring Korea. The findings provide a deeper understanding of how crisis events, including political instability and economic fluctuations, can affect inbound tourism in geographically and historically interrelated countries. Therefore, to minimize the negative effect on tourism demand, it is important for practitioners to consider potential external threats when making forecasts.