bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalytic Routes to Produce Polyphenolic Esters (PEs) from Biomass Feedstocks
Authors: Faggiano Antonio , Ricciardi Maria , Proto Antonio
Published: April 2022

Polyphenolic esters (PEs) are valuable chemical compounds that display a wide spectrum of activities (e.g., anti-oxidative effects). As a result, their production through catalytic routes is an attractive field of research. The present review aims to discuss recent studies from the literature regarding the catalytic production of PEs from biomass feedstocks, namely, naturally occurred polyphenolic compounds. Several synthetic approaches are reported in the literature, mainly bio-catalysis and to a lesser extent acid catalysis. Immobilized lipases (e.g., Novozym 435) are the preferred enzymes thanks to their high reactivity, selectivity and reusability. Acid catalysis is principally investigated for the esterification of polyphenolic acids with fatty alcohols and/or glycerol, using both homogeneous (p-toluensulfonic acid, sulfonic acid and ionic liquids) and heterogeneous (strongly acidic cation exchange resins) catalysts. Based on the reviewed publications, we propose some suggestions to improve the synthesis of PEs with the aim of increasing the greenness of the overall production process. In fact, much more attention should be paid to the use of new and efficient acid catalysts and their reuse for multiple reaction cycles.
A Study on the Effects of Gallium Droplet Consumption and Post Growth Annealing on Te-Doped GaAs Nanowire Properties Grown by Self-Catalyzed Molecular Beam Epitaxy
Authors: Devkota Shisir , Parakh Mehul , Ramaswamy Priyanka , Kuchoor Hirandeep , Penn Aubrey , Reynolds Lewis , Iyer Shanthi
Published: April 2022

In this work, the effects of arsenic (As) flux used during gallium (Ga) seed droplet consumption and the post-growth annealing on the optical, electrical, and microstructural properties of self-catalyzed molecular beam epitaxially grown tellurium (Te)-doped GaAs nanowires (NWs) have been investigated using a variety of characterization techniques. NWs using the same amount of As flux for growth of the seed droplet consumption demonstrated reduced density of stacking faults at the NW tip, with four-fold enhancement in the 4K photoluminescence (PL) intensity and increased single nanowire photocurrent over their higher As flux droplet consumption counterparts. Post-growth annealed NWs exhibited an additional low-energy PL peak at 1.31 eV that significantly reduced the overall PL intensity. The origin of this lower energy peak is assigned to a photocarrier transition from the conduction band to the annealing assisted Te-induced complex acceptor state (TeAsVGa−). In addition, post-growth annealing demonstrated a detrimental impact on the electrical properties of the Te-doped GaAs NWs, as revealed by suppressed single nanowire (SNW) and ensemble NW photocurrent, with a consequent enhanced low-frequency noise level compared to as-grown doped NWs. This work demonstrates that each parameter in the growth space must be carefully examined to successfully grow self-catalyzed Te-doped NWs of high quality and is not a simple extension of the growth of corresponding intrinsic NWs.
Genetic Variations and mRNA Expression of Goat DNAH1 and Their Associations with Litter Size
Authors: Wang Zhen , Wang Ruolan , Pan Chuanying , Chen Hong , Qu Lei , Wu Lian , Guo Zhengang , Zhu Haijing , Lan Xianyong
Published: April 2022

Dynein Axonemal Heavy Chain 1 (DNAH1) encodes proteins which provide structural support for the physiological function and motor structure of spermatozoa (hereafter referred to as sperm) and ova. This study found that three single nucleotide polymorphisms (SNPs), the 27-bp insertion/deletion (InDel) mutations and three exonic copy number variations (CNVs) within DNAH1 were significantly associated with litter size of Shaanbei white cashmere goats (n = 1101). Goats with the wildtypes of these three SNPs had higher litter sizes than other carriers (p < 0.05). II genotype of the 27-bp InDel had the highest litter size compared with ID carriers (p = 0.000022). The gain genotype had the largest litter sizes compared with the loss or medium carriers for the three CNV mutations (p < 0.01). Individuals with the AA-TT-CC-II-M1-M2-M3 and AA-TT-CC-II-G1-G2-M3 combination genotypes had larger litter sizes compared with the other genotypes. This study also showed the DNAH1 expression in mothers of multiple kids was higher than mothers of single kids. These three SNPs, the 27-bp InDel and three CNVs in DNAH1 could be used as molecular markers for the selection of goat reproductive traits.
Key Signaling in Alcohol-Associated Liver Disease: The Role of Bile Acids
Authors: Way Grayson W. , Jackson Kaitlyn G. , Muscu Shreya R. , Zhou Huiping
Published: April 2022

Alcohol-associated liver disease (ALD) is a spectrum of diseases, the onset and progression of which are due to chronic alcohol use. ALD ranges, by increasing severity, from hepatic steatosis to alcoholic hepatitis (AH) and alcohol-associated cirrhosis (AC), and in some cases, can lead to the development of hepatocellular carcinoma (HCC). ALD continues to be a significant health burden and is now the main cause of liver transplantations in the United States. ALD leads to biological, microbial, physical, metabolic, and inflammatory changes in patients that vary depending on disease severity. ALD deaths have been increasing in recent years and are projected to continue to increase. Current treatment centers focus on abstinence and symptom management, with little in the way of resolving disease progression. Due to the metabolic disruption and gut dysbiosis in ALD, bile acid (BA) signaling and metabolism are also notably affected and play a prominent role in disease progression in ALD, as well as other liver disease states, such as non-alcoholic fatty liver disease (NAFLD). In this review, we summarize the recent advances in the understanding of the mechanisms by which alcohol consumption induces hepatic injury and the role of BA-mediated signaling in the pathogenesis of ALD.
Pediatric Asthma: A Daily Challenge
Authors: Ciprandi Giorgio
Published: April 2022

Asthma is a prevalent disease in children and adolescents, as the prevalence concerns about 10% of the general pediatric population [...]
Double Pre-Bending of an Intramedullary Nail Is the Minimal Invasive Osteosynthesis Solution for Dia-Metaphyseal Fractures of the Radius in Children: Technical Note and Case Series
Authors: Krohn Carsten
Published: April 2022

Whereas in paediatric traumatology for diaphyseal fractures of the radius (intramedullary nail), as well as metaphyseal fractures (K-wire), minimal invasive methods for osteosynthesis were established as gold standard, the ideal osteosynthesis of fractures of the dia-metaphyseal area remains controversial. In this article, the author describes his own minimal invasive technique, using an intramedullary nail that must be pre-bent twice to achieve a stable reduction, with three-point support. The material used for this new surgical technique is an ordinary intramedullary nail. If not available, the operation can also be performed with a sufficiently lengthy K-wire. The intramedullary nail needs to be pre-bent twice, which follows a standardised procedure. A small case series is included to visualise the scope of this minimal-invasive method.
The Ferrite Layer on the Surface of Carbon Steel Obtained by Precisely Designed Cooling Rate Heat Treatment and Its Microstructure Analysis
Authors: Yang Weijiang , Zhou Yining , Ma Yunzan , Liu Kejia , Wang Lianbo , Chen Kun
Published: April 2022

This paper presents obtaining a single-phase ferrite layer with low content of carbon (the average thickness is about 156–246 µm) on the surface of 0.45% carbon steel by precisely designing the cooling rate during heat treatment, and its mechanical properties show a graded change in the cross-section. It may be achieved by preparing gradient/multilayer materials with more commonly utilized structures or a specific performance. Combining with phase identification by employing electron backscatter diffraction (EBSD) of the layer in this study is BCC ferritic phases. Based on the examination of Continuous Cooling Transformation (CCT) curves, the following conclusions are given. Under the cooling process with gradient temperature, a ferrite layer first forms on the outer lower temperature surface of the 0.45% carbon steel and subsequently develops by pushing the surplus carbon to the inner higher temperature austenite region. It is corroborated by the experimental findings of carbon contents dispersion acquired by electron probe microanalyzer (EPMA). Finally, the experimental findings of grain orientations and size distribution defined by electron backscatter diffraction (EBSD) are given as requirements for microscopic interpretation of the combination of excellent strength and bending capabilities of materials. Furthermore, the experimental findings of oxidation precisely specified the cooling rate during heat treatment of Cu coating samples, which are defined as criteria for identifying the production mechanism of the surface ferrite layer. It provides a theoretical explanation and direct experimental proof for creating the ferrite layer on the surface.
Structural Determination of Pectins by Spectroscopy Methods
Authors: Kozioł Agata , Środa-Pomianek Kamila , Górniak Agata , Wikiera Agnieszka , Cyprych Konrad , Malik Magdalena
Published: April 2022

Plant polysaccharides include pectins, which are responsible for an important role in plant physiology and are part of the plant cell wall. These compounds are known as gelling and stabilizing agents, which are widely used in the food industry. The scientific literature lacks precise information on the spectroscopy of apple pectin and citrus pectin. Therefore, the aim of this work was to test and compare the physicochemical properties of these compounds. The curves of FT-IR, NMR, ESI-MS, and thermogravimetric analysis (TGA) of pectin samples were measured and discussed. The analysis of the spectroscopic results confirms that the isolated pectins using various enzymes (xylanase and cellulase) have a structure similar to the commercially available pectin (PectaSol-C), with a noticeable change in morphology. These characteristics are helpful for further basic research and application.
High-Temperature Oxidation Resistance and Tribological Properties of Al2O3/ta-C Coating
Authors: Alamgir Asad , Bogatov Andrei , Jõgiaas Taivo , Viljus Mart , Raadik Taavi , Kübarsepp Jakob , Sergejev Fjodor , Lümkemann Andreas , Kluson Jan , Podgursky Vitali
Published: April 2022

The focus is on the oxidation resistance and tribological performance of ta-C and Al2O3/ta-C coatings. The wear tests were carried out on the ball on disc tribometer at room (25 °C) and high (400, 450 and 500 °C) temperatures in ambient air with Si3N4 balls as counterbodies. Scanning electron microscopy and Raman spectroscopy were used to analyze the surface morphology and chemical bonding, respectively. The Al2O3/ta-C coating exhibited better oxidation resistance and tribological performance at elevated temperatures than the ta-C coating. The Raman analysis revealed that a thin alumina layer suppresses structural changes in the ta-C coating at elevated temperatures, thus preserving the sp3 content.
Electro-Oxidation of Metal Oxide-Fabricated Graphitic Carbon Nitride for Hydrogen Production via Water Splitting
Authors: Ashfaq Tayyaba , Khan Mariam , Arshad Ifzan , Ahmad Awais , Ali Shafaqat , Aftab Kiran , Al-Kahtani Abdullah , Mohamed Tighezza Ammar
Published: April 2022

Hydrogen is a great sourcez of energy due to having zero emission of carbon-based contents. It is found primarily in water, which is abundant and renewable. For electrochemical splitting of water molecules, it is necessary to use catalytic materials that minimize energy consumption. As a famous carbon material, graphitic carbon nitride, with its excellent physicochemical properties and diversified functionalities, presents great potential in electrocatalytic sensing. In the present work, graphitic carbon nitride-fabricated metal tungstate nanocomposites are synthesized by the hydrothermal method to study their applications in catalysis, electrochemical sensing, and water splitting for hydrogen production. Nanocomposites using different metals, such as cobalt, manganese, strontium, tin, and nickel, were used as a precursor are synthesized via the hydrothermal process. The synthesized materials (g-C3N4/NiWO4, g-C3N4/MnWO4, g-C3N4/CoWO4, g-C3N4/SnWO4, g-C3N4/SrWO4) were characterized using different techniques, such as FTIR and XRD. The presence of a functional groups between the metal and tungstate groups was confirmed by the FTIR spectra. All the nanocomposites show a tungstate peak at 600 cm−1, while the vibrational absorption bands for metals appear in the range of 400–600 cm−1. X-ray diffraction (XRD) shows that the characteristic peaks matched with the JCPDS in the literature, which confirmed the successful formation of all nanocomposites. The electrochemical active surface area is calculated by taking cyclic voltammograms of the potassium–ferrocyanide redox couple. Among the entire series of metal tungstate, the g-C3N4/NiWO4 has a large surface area owing to the high conductive properties towards water oxidation. In order to study the electrocatalytic activity of the as-synthesized materials, electrochemical water splitting is performed by cyclic voltammetry in alkaline medium. All the synthesized materials proved to be efficient catalysts with enhanced conductive properties towards water oxidation. Among the entire series, g-C3N4-NiWO4 is a very efficient electrocatalyst owing to its higher active surface area and conductive activity. The order of electrocatalytic sensing of the different composites is: g-C3N4-NiWO4 > g-C3N4-SrWO4 > g-C3N4-CoWO4 > g-C3N4-SnWO4 > g-C3N4-MnWO4. Studies on electrochemically synthesized electrocatalysts revealed their catalytic activity, indicating their potential as electrode materials for direct hydrogen evolution for power generation.
Age-Defying and Photoprotective Potential of Geranium/Calendula Essential Oil Encapsulated Vesicular Cream on Biochemical Parameters against UVB Radiation Induced Skin Aging in Rat
Authors: Lohani Alka , Morganti Pierfrancesco
Published: April 2022

UVB irradiation promotes the production of reactive oxygen species, which can lead to an increase in oxidative stress in the cell and the generation of toxic components, resulting in photoaging. Essential oils (EOs) are well-known in the cosmetics sector for their beneficial effects, as they have a wide range of biological activities. Considering this fact, the current study investigates the photoprotective potential of geranium essential oil (GEO)/calendula essential oil (CEO) encapsulated vesicular cream on the biochemical parameters of the skin of albino rats exposed to UVB radiation. After 30 days of treatment with cream formulations and UVB irradiation, the skin tissue was assayed for several biochemical parameters and histopathology analysis. The results of biochemical study revealed that, in comparison to non-vesicular creams, vesicular cream formulations were able to protect the endogenous skin natural antioxidant system by maintaining superoxide dismutase, catalase, total protein, ascorbic acid, and hydroxyproline levels and by decreasing malondialdehyde levels in the skin after UVB exposure. Changes in various cellular structures along with the change in the epidermis and dermis of the skin after UVB exposure in the treated group were observed by a histopathology of skin tissue and compared to the non-treated group, which revealed the skin damaging effect of UVB radiation and the protective effect of vesicular creams. The results suggest that the GEO/CEO-encapsulated vesicular creams have the potential to protect the skin against harmful UVB radiation by maintaining the natural antioxidant defence mechanism of the skin. In conclusion, this research presents novel herbal cosmetic formulations with improved antioxidant capacity and photoprotective potential that may help to slow down the skin aging process.
Cracking Behavior, Microstructure and Properties of Selective Laser Melted Al-Mn-Mg-Sc-Zr Alloy
Authors: Zhai Ziyu , Pan Wei , Liang Bo , Liu Yantao , Zhang Yongzhong
Published: April 2022

In this paper, the cracking of Al-Mn-Mg-Sc-Zr alloys prepared by selective laser melting (SLM) was comprehensively explored and the influence of process parameters on the generation and propagation of cracks was deeply studied. It was found that the higher laser power and volume energy density will lead to a decrease in the relative density of the material. The lower laser power or volume energy density will lead to cracking of the alloy. The microstructure analysis indicated that plenty of manganese-rich second phases precipitated at the bottom of the melt pool, which increased the tendency of cracking occurred at the bottom of the melt pool. Through the optimization of the process parameters, the SLM forming process parameters of the Al-5.22Mn-1.16Mg-0.81Sc-0.46Zr alloy are successfully obtained, and the crack-free tensile samples are prepared. The microstructure and mechanical properties of the as-deposited aluminum-manganese alloy is analyzed. The bottom and inside of the melt pool are equiaxed grains. The size of the equiaxial grains at the bottom of the melt pool is less than 2 μm, and the coarse equiaxial grains inside the melt pool are approximately 5 μm. As-deposited alloy has a room temperature tensile strength of 455.2 ± 0.7 MPa and elongation of 15.4 ± 0.3%. This study provides guidance for selective laser melting forming of high-strength aluminum-manganese alloy parts, and promotes the industrial production of high-strength aluminum alloy near net forming complex parts.
Evaluation of the Structural Deviation of Cu/Cu2O Nanocomposite Using the X-ray Diffraction Analysis Methods
Authors: Lam Nguyen , Smith Ryan , Le Nam , Thuy Chau , Tamboli Mohaseen , Tamboli Asiya , Alshehri Sultan , Ghoneim Mohammed , Truong Nguyen , Jung Jae
Published: April 2022

We successfully synthesized Cu/Cu2O nanocomposites using the wet chemical synthesis method. All X-ray diffraction (XRD), Reference Intensity Ratio (RIR), and Rietveld refinement methods confirmed that the compounds Cu and Cu2O are free of impurities. Scanning Electron Microscope (SEM) and Transmission electron microscopy (TEM) images show the morphology and interactions of Cu and Cu2O in the structure. The formation mechanism is also explained by five stages: precursor, nucleation, growth, aging, and reduction. The changes in crystallization parameters under variations in reaction temperature (Tv) and stirring speed (Sv) were confirmed by agreement with the XRD database. The lattice constant in the crystal of nanocomposite increases with rising temperature in the reaction, leading to unit cell expansion, while increasing the stirring—rate leads to a random size distribution of the lattice parameter. Due to the imperfect growth of the crystal, the induced crystallite size was calculated using the Williamson-Hall model, and the precise lattice parameter values were calculated using the Nelson-Riley function.
Diversity and Traditional Use Knowledge of Medicinal Plants among Communities in the South and South-Eastern Zones of the Tigray Region, Ethiopia
Authors: Mengistu Dejene K. , Mohammed Jemal N. , Kidane Yosef Gebrehawaryat , Fadda Carlo
Published: April 2022

In the present study, the diversity of medicinal plants (MPs) and associated traditional knowledge of rural community herbalists to treat human and animals’ diseases were assessed in two districts in the Tigray Region, Ethiopia. Study participants were randomly selected for survey and focus group discussions, while key informant traditional healers were identified through snowball/chain-referral sampling. The informant consensus factor (FIC) by ailment category and fidelity level (FL) for some MPs were determined. About 97 MP species were identified. Leaves, roots, and seeds are the parts predominantly used for phytomedication preparation to treat 30 human and 5 animal diseases. Diseases, such as epilepsy, arthritis, otitis media, and fever, are treated with a combination of 2–4 MPs. The FIC value ranged from 0.29–1.00, with most human diseases showing an FIC value of above 0.7. The FL value for the MPs ranged from 53–100%, with plants used to treat more than one disease tending to have lower FL values. Higher values of FIC and FL indicate high levels of traditional knowledge used to identify and administer medicinal preparations. Despite the frequent use of MPs, the four-cell analysis showed that most of them risk extinction due anthropogenic and climate factors. We recommend botanical gardens as a solution to sustainable conservation, study, education and a source for these declining MP species.
Novel User-Friendly Application for MRI Segmentation of Brain Resection following Epilepsy Surgery
Authors: Billardello Roberto , Ntolkeras Georgios , Chericoni Assia , Madsen Joseph R. , Papadelis Christos , Pearl Phillip L. , Grant Patricia Ellen , Taffoni Fabrizio , Tamilia Eleonora
Published: April 2022

Delineation of resected brain cavities on magnetic resonance images (MRIs) of epilepsy surgery patients is essential for neuroimaging/neurophysiology studies investigating biomarkers of the epileptogenic zone. The gold standard to delineate the resection on MRI remains manual slice-by-slice tracing by experts. Here, we proposed and validated a semiautomated MRI segmentation pipeline, generating an accurate model of the resection and its anatomical labeling, and developed a graphical user interface (GUI) for user-friendly usage. We retrieved pre- and postoperative MRIs from 35 patients who had focal epilepsy surgery, implemented a region-growing algorithm to delineate the resection on postoperative MRIs and tested its performance while varying different tuning parameters. Similarity between our output and hand-drawn gold standards was evaluated via dice similarity coefficient (DSC; range: 0–1). Additionally, the best segmentation pipeline was trained to provide an automated anatomical report of the resection (based on presurgical brain atlas). We found that the best-performing set of parameters presented DSC of 0.83 (0.72–0.85), high robustness to seed-selection variability and anatomical accuracy of 90% to the clinical postoperative MRI report. We presented a novel user-friendly open-source GUI that implements a semiautomated segmentation pipeline specifically optimized to generate resection models and their anatomical reports from epilepsy surgery patients, while minimizing user interaction.
Unusual Presentation of Clear Cell Odontogenic Carcinoma: Case Report and Literature Review
Authors: Verdeja Raúl , Stauffer Edouard , Lombardi Tommaso
Published: April 2022

Clear cell odontogenic carcinoma (CCOC) is a rare, aggressive epithelial neoplasm of the jaw first described in 1985 by Hansen and classified as an odontogenic malignant tumor in the 2005 WHO classification. To date, only 117 cases have been reported in the literature written in English. In this paper, we report the atypical presentation of a pericoronal localized tumor in the right mandibular wisdom tooth discovered during a routine radiologic examination. The patient, a 44-year-old healthy female, was referred by her general dental practitioner for examination of temporomandibular dysfunction and recurrent myofascial pain. Anamnesis and clinical examination did not suggest tumoral disease. The osteolytic lesion was removed, and histological examination revealed a clear cell odontogenic tumor (CCOT) of the right posterior lower jaw. Segmental lower jaw resection was performed, and a free iliac crest bone transplant was fixed with mandibular reconstruction plate. No cervical neck dissection was needed. A five-year follow-up examination shows excellent local and systemic recovery and no sign of tumor recurrence. The patient still suffers from bruxism and myofascial related pain, which are treated conservatively with a Michigan splint and physiotherapy. Based on this additional case, we review the literature and discuss the challenging diagnostic aspects, the unusual clinical presentation, and the treatment of CCOC.
Osteoradionecrosis of the Temporal Bone as a Rare Cause of Facial Nerve Palsy
Authors: Schmidt Florian , Bradley Katy , Volk Gerd Fabian
Published: April 2022

We present a case of a 69-year-old male who presented with acute left facial nerve palsy, serous bloody otorrhea, otalgia, and exposed necrotic bone on the floor of his left ear canal. His medical history revealed a left canal wall-down (CWD) mastoidectomy thirty years ago. Subsequently, twenty years later, he received primary chemoradiotherapy for tonsil cancer on the same side. The patient’s medical history, the typical clinical picture, and a comprehensive diagnostic workup, including imaging modalities and electrophysiology, finally led to a diagnosis of osteoradionecrosis of the temporal bone (ORNTB), with secondary facial nerve palsy. The facial nerve, unfortunately, did not recover and treatment remained conservative, as per the patient’s preference. ORNTB is a rare, delayed complication after radiotherapy for head and neck cancer, which occurs after about 8 years and a minimum of 41.8 Gray of radiation to the affected area. Facial nerve palsy in ORNTB is rare, with only 2.9% of patients experiencing it, but, in our particular case, the patient had undergone an additional CWD mastoidectomy. The treatment options need to be personalized and aimed at symptom control. There should be awareness of the condition among ENT specialists, especially during head and neck cancer follow-ups, and in patients who have had mastoidectomy and radiotherapy affecting the ipsilateral temporal bone.
Antibiotics Efficiency in the Infection Complications Prevention after Third Molar Extraction: A Systematic Review
Authors: Sologova Diana , Diachkova Ekaterina , Gor Ilana , Sologova Susanna , Grigorevskikh Ekaterina , Arazashvili Liana , Petruk Pavel , Tarasenko Svetlana
Published: April 2022

(1) Background: Antibiotics are used in every medical field including dentistry, where they are used for the prevention of postoperative complications in routine clinical practice during the third molar extraction. (2) Methods: This study is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The present systematic review aimed to evaluate and systematize the use of antibacterial drugs in order to prevent postoperative complications in outpatient oral surgery for wisdom teeth extraction. We conducted a systematic review using electronic databases such as Medline PubMed, Scopus, and the Cochrane Central Register of Controlled Trials. Considering inclusion and exclusion criteria, we included randomized clinical trials published up to 2021 investigating the antibiotic prescription for third molar extraction. (3) Results: We selected 10 studies after the application of inclusion and exclusion criteria. The results showed that the most widely used antibiotic was amoxicillin both with and without clavulanic acid, in different dosages and duration. There were no statistically significant differences between treatment groups for development of postoperative complications. (4) Conclusions: Based on the analysis of the included studies, penicillin is currently the most widely prescribed group of antibiotics. The widespread use of this antibiotic group can lead to antimicrobial resistance (AMR). Due to increasing prevalence of bacteria resistance to penicillins, clinicians should carefully prescribe these antibiotics and be aware that the widespread use of amoxicillin may do more harm than good for the population.
Numerical Solutions of Variable Coefficient Higher-Order Partial Differential Equations Arising in Beam Models
Authors: Ghafoor Abdul , Haq Sirajul , Hussain Manzoor , Abdeljawad Thabet , Alqudah Manar A.
Published: April 2022

In this work, an efficient and robust numerical scheme is proposed to solve the variable coefficients’ fourth-order partial differential equations (FOPDEs) that arise in Euler–Bernoulli beam models. When partial differential equations (PDEs) are of higher order and invoke variable coefficients, then the numerical solution is quite a tedious and challenging problem, which is our main concern in this paper. The current scheme is hybrid in nature in which the second-order finite difference is used for temporal discretization, while spatial derivatives and solutions are approximated via the Haar wavelet. Next, the integration and Haar matrices are used to convert partial differential equations (PDEs) to the system of linear equations, which can be handled easily. Besides this, we derive the theoretical result for stability via the Lax–Richtmyer criterion and verify it computationally. Moreover, we address the computational convergence rate, which is near order two. Several test problems are given to measure the accuracy of the suggested scheme. Computations validate that the present scheme works well for such problems. The calculated results are also compared with the earlier work and the exact solutions. The comparison shows that the outcomes are in good agreement with both the exact solutions and the available results in the literature.
Multiview Clustering of Adaptive Sparse Representation Based on Coupled P Systems
Authors: Zhang Xiaoling , Liu Xiyu
Published: April 2022

A multiview clustering (MVC) has been a significant technique to dispose data mining issues. Most of the existing studies on this topic adopt a fixed number of neighbors when constructing the similarity matrix of each view, like single-view clustering. However, this may reduce the clustering effect due to the diversity of multiview data sources. Moreover, most MVC utilizes iterative optimization to obtain clustering results, which consumes a significant amount of time. Therefore, this paper proposes a multiview clustering of adaptive sparse representation based on coupled P system (MVCS-CP) without iteration. The whole algorithm flow runs in the coupled P system. Firstly, the natural neighbor search algorithm without parameters automatically determines the number of neighbors of each view. In turn, manifold learning and sparse representation are employed to construct the similarity matrix, which preserves the internal geometry of the views. Next, a soft thresholding operator is introduced to form the unified graph to gain the clustering results. The experimental results on nine real datasets indicate that the MVCS-CP outperforms other state-of-the-art comparison algorithms.
Entropy Generation Analysis of the Flow Boiling in Microgravity Field
Authors: Sun Zijian , Zhang Haochun , Wang Qi , Sun Wenbo
Published: April 2022

Entropy generation analysis of the flow boiling in microgravity field is conducted in this paper. A new entropy generation model based on the flow pattern and the phase change process is developed in this study. The velocity ranges from 1 m/s to 4 m/s, and the heat flux ranges from 10,000 W/m2 to 50,000 W/m2, so as to investigate their influence on irreversibility during flow boiling in the tunnel. A phase–change model verified by the Stefan problem is employed in this paper to simulate the phase–change process in boiling. The numerical simulations are carried out on ANSYS-FLUENT. The entropy generation produced by the heat transfer, viscous dissipation, turbulent dissipation, and phase change are observed at different working conditions. Moreover, the Be number and a new evaluation number, EP, are introduced in this paper to investigate the performance of the boiling phenomenon. The following conclusions are obtained: (1) a high local entropy generation will be obtained when only heat conduction in vapor occurs near the hot wall, whereas a low local entropy generation will be obtained when heat conduction in water or evaporation occurs near the hot wall; (2) the entropy generation and the Be number are positively correlated with the heat flux, which indicates that the heat transfer entropy generation becomes the major contributor of the total entropy generation with the increase of the heat flux; (3) the transition of the boiling status shows different trends at different velocities, which affects the irreversibility in the tunnel; (4) the critical heat flux (CHF) is the optimal choice under the comprehensive consideration of the first law and the second law of the thermodynamics.
AI Ekphrasis: Multi-Modal Learning with Foundation Models for Fine-Grained Poetry Retrieval
Authors: Jabbar Muhammad Shahid , Shin Jitae , Cho Jun-Dong
Published: April 2022

Artificial intelligence research in natural language processing in the context of poetry struggles with the recognition of holistic content such as poetic symbolism, metaphor, and other fine-grained attributes. Given these challenges, multi-modal image–poetry reasoning and retrieval remain largely unexplored. Our recent accessibility study indicates that poetry is an effective medium to convey visual artwork attributes for improved artwork appreciation of people with visual impairments. We, therefore, introduce a deep learning approach for the automatic retrieval of poetry suitable to the input images. The recent state-of-the-art CLIP provides a way for multi-modal visual and text features matched using cosine similarity. However, it lacks shared cross-modality attention features to model fine-grained relationships. The proposed approach in this work takes advantage of strong pre-training of the CLIP model and overcomes its limitations by introducing shared attention parameters to better model the fine-grained relationship between both modalities. We test and compare our proposed approach using the expertly annotated MiltiM-Poem dataset, which is considered the largest public image–poetry pair dataset for English poetry. The proposed approach aims to solve the problems of image-based attribute recognition and automatic retrieval for fine-grained poetic verses. The test results reflect that the shared attention parameters alleviate fine-grained attribute recognition, and the proposed approach is a significant step towards automatic multi-modal retrieval for improved artwork appreciation of people with visual impairments.
Integrated Yaw Stability Control of Electric Vehicle Equipped with Front/Rear Steer-by-Wire Systems and Four In-Wheel Motors
Authors: Seo Younghoon , Cho Kwanghyun , Nam Kanghyun
Published: April 2022

This paper presents the integrated motion control method for an electric vehicle (EV) equipped with a front/rear steer-by-wire (SbW) system and four in-wheel motor (IWM). The proposed integrated motion control method aims to maintain stable cornering. To maintain vehicle agility and stability, the lateral force and yaw rate commands of the vehicle are generated by referring to the neutral steering characteristics. The driver’s driving force command, the lateral force command based on the bicycle model, and the yaw moment generated by the high-level controller are distributed into the driving force of each wheel and the lateral force of the front and rear wheels by the yaw moment distribution. Finally, the distributed forces are directly controlled by a low-level controller. To directly control the forces, a driving force observer and a lateral force observer were introduced via driving force estimation in the IWMs and rack force estimation in the SbW system. The control performance is verified through computer simulations.
Smart Mobile Learning Success Model for Higher Educational Institutions in the Context of the COVID-19 Pandemic
Authors: Almaiah Mohammed Amin , Ayouni Sarra , Hajjej Fahima , Lutfi Abdalwali , Almomani Omar , Awad Ali Bani
Published: April 2022

Smart mobile learning (M-learning) applications have shown several new benefits for higher educational institutions during the COVID-19 pandemic, during which such applications were used to support distance learning. Therefore, this study aims to examine the most important drivers influencing the adoption of M-learning by using the technology acceptance model (TAM). The structural equation modelling (SEM) method was used to test the hypotheses in the proposed model. Data were collected via online questionnaires from 520 undergraduate and postgraduate students at four universities in Saudi Arabia. Partial least squares (PLS)–SEM was used to analyse the data. The findings indicated that M-learning acceptance is influenced by three main factors, namely, awareness, IT infrastructure (ITI), and top management support. This research contributes to the body of knowledge on M-learning acceptance practices. Likewise, it may help to facilitate and promote the acceptance of M-learning among students in Saudi universities.
An RG-FLAT-CRF Model for Named Entity Recognition of Chinese Electronic Clinical Records
Authors: Li Jiakang , Liu Ruixia , Chen Changfang , Zhou Shuwang , Shang Xiaoyi , Wang Yinglong
Published: April 2022

The goal of Clinical Named Entity Recognition (CNER) is to identify clinical terms from medical records, which is of great importance for subsequent clinical research. Most of the current Chinese CNER models use a single set of features that do not consider the linguistic characteristics of the Chinese language, e.g., they do not use both word and character features, and they lack morphological information and specialized lexical information on Chinese characters in the medical field. We propose a RoBerta Glyce-Flat Lattice Transformer-CRF (RG-FLAT-CRF) model to address this problem. The model uses a convolutional neural network to discern the morphological information hidden in Chinese characters, and a pre-trained model to obtain vectors with medical features. The different vectors are stitched together to form a multi-feature vector. To use lexical information and avoid the problem of word separation errors, the model uses a lattice structure to add lexical information associated with each word, which can be used to avoid the problem of word separation errors. The RG-FLAT-CRF model scored 95.61%, 85.17%, and 91.2% for F1 on the CCKS 2017, 2019, and 2020 datasets, respectively. We used statistical tests to compare with other models. The results show that most p-values less than 0.05 are statistically significant.
Adversarial Attack and Defense: A Survey
Authors: Liang Hongshuo , He Erlu , Zhao Yangyang , Jia Zhe , Li Hao
Published: April 2022

In recent years, artificial intelligence technology represented by deep learning has achieved remarkable results in image recognition, semantic analysis, natural language processing and other fields. In particular, deep neural networks have been widely used in different security-sensitive tasks. Fields, such as facial payment, smart medical and autonomous driving, which accelerate the construction of smart cities. Meanwhile, in order to fully unleash the potential of edge big data, there is an urgent need to push the AI frontier to the network edge. Edge AI, the combination of artificial intelligence and edge computing, supports the deployment of deep learning algorithms to edge devices that generate data, and has become a key driver of smart city development. However, the latest research shows that deep neural networks are vulnerable to attacks from adversarial example and output wrong results. This type of attack is called adversarial attack, which greatly limits the promotion of deep neural networks in tasks with extremely high security requirements. Due to the influence of adversarial attacks, researchers have also begun to pay attention to the research in the field of adversarial defense. In the game process of adversarial attacks and defense technologies, both attack and defense technologies have been developed rapidly. This article first introduces the principles and characteristics of adversarial attacks, and summarizes and analyzes the adversarial example generation methods in recent years. Then, it introduces the adversarial example defense technology in detail from the three directions of model, data, and additional network. Finally, combined with the current status of adversarial example generation and defense technology development, put forward challenges and prospects in this field.
Modeling and Extended State Observer-Based Backstepping Control of Underwater Electro Hydrostatic Actuator with Pressure Compensator and External Load
Authors: Nie Yong , Liu Jiajia , Lao Zhenhua , Chen Zheng
Published: April 2022

Electro hydrostatic actuator (EHA) has been successfully developed for flight control applications to replace the cumbersome centralized hydraulic system. It also has excellent potential for ocean applications due to its advantages on miniaturization and energy-savings. One of the special technologies for EHA’s underwater application is pressure compensation, which is used to equalize the return pressure of the hydraulic system and the seawater pressure. This paper investigates the modeling and control design of underwater EHA to improve performance, especially considering the effect of additional pressure compensator and uncertain external load. The nonlinear hydraulic model is extended by the dynamic characteristics of the pressure compensator. Two low-order extended state observers were constructed to cope with the external load fore and the effect of the pressure compensator, respectively. The backstepping methods were designed to guarantee the robust stability of the entire high-order nonlinear hydraulic system. Finally, the theoretical proving and simulation on Matlab/Simulink are conducted to demonstrate the high tracking performance of the proposed control strategy.
Three-Level Active Power Filter Based on Model Predictive Control
Authors: Gao Hanying , Zhang Weihao , Ren Mingjie , Liu Xiangnan
Published: April 2022

The model predictive control (MPC) algorithm is used in the harmonic compensation of active power filter (APF), which has a fast dynamic response and does not require a PWM modulation model. However, this method has some shortcomings, such as the mass computing and difficult selections of weight factors. To solve these problems, this paper proposes a single objective function improved MPC algorithm based on sector judgment, which only takes the reference current and feedback current as the objective function, omits the weight coefficient setting process, and reduces the number of rolling optimization from 27 to 7, thus reducing the computing time and control complexity. The improved model predictive control is applied to APF. Finally, the simulations and experiments show that the improved MPC algorithm is accurate and efficient.
Resilience of Reed-Solomon Codes against Single-Frequency Electromagnetic Disturbances: Fault Mechanisms and Fault Elimination through Symbol Inversion
Authors: Memar Pejman , Vankeirsbilck Jens , Vanoost Dries , Claeys Tim , Pissoort Davy , Boydens Jeroen
Published: April 2022

Modern safety-critical systems depend heavily on communication networks while operating in increasingly polluted electromagnetic environments. Forward Error Correction codes are increasingly being used in safety-critical applications; however, vulnerabilities can still be caused by undetected corrupted data. Within this paper, the effectiveness of primitive Reed–Solomon Codes under single-frequency electromagnetic disturbances is assessed. Additionally, the impact of various parameters including the message length, the Reed–Solomon Codes’ symbol size, and the amplitude of the induced voltages are also investigated. Simulations show that, at harmonics and some certain ratios of the bit-rate frequency, the susceptibility of Reed–Solomon Codes relative to this type of disturbance increases substantially. In worse-case scenarios, the rate of undetected corrupted data at these ratios could increase to values above 80%. It is shown that the main reason that Reed–Solomon Codes fail to detect such errors is due to the repetitive nature of code words’ symbols, as well as a special relation among the symbol size, the channel’s bit-rate, and the disturbance frequency. Accordingly, this paper proposes to add an extra inversion layer to the communication protocol to enhance the resiliency of these codes against single-frequency electromagnetic disturbances. Finally, it is shown that the proposed layer substantially mitigates the ratio of undetected corrupted data under the considered electromagnetic environment. By using the proposed approach, the rate of undetected corrupted data at the frequencies of concern decreased to values near 0%.
Pore Characteristics and Gas Preservation of the Lower Cambrian Shale in a Strongly Deformed Zone, Northern Chongqing, China
Authors: Meng Guangming , Li Tengfei , Gai Haifeng , Xiao Xianming
Published: April 2022

The Lower Paleozoic marine shale in southern China has undergone several strong tectonic transformations in an extensive region outside the Sichuan Basin. Although some shale strata underwent strong deformation, they still contain a significant amount of shale gas. The gas preservation mechanism in the strongly deformed shale has become the focus of attention. In this paper, the Lower Cambrian gas-bearing shale samples with a strong deformation taken from an exploration well in northern Chongqing, China, were investigated on their pore types and structure, with the aim to reveal the reason for the gas preservation. The pore types of the Lower Cambrian shale are dominated by microfractures and interparticle (interP) pores occurring mainly between clay minerals and between organic matter (OM) and clay minerals, while pores within OM that can be observed by FE-SEM (field emission-scanning electron microscopy) are rare. The shale has a low porosity, with an average of 1.56%, which is mainly controlled by the clay mineral content. The adsorption experiments of low pressure N2 (LPNA) and CO2 (LPCA) indicate that the shale is rich in micropores and small mesopores (<2–3 nm) provided mainly by OM, but mesopores with a size range of 3–50 nm are underdeveloped. The shale, as revealed by LPNA data, has dominant slit-like or plate-like pores and an obvious low-pressure hysteresis (LPH), indicating a low gas diffusion. The deformed shale samples with a removal of OM by oxidation and their isolated kerogen further indicate that the LPH is completely related to OM, without any relationship with minerals, while an undeformed shale sample, taken from another well for a comparison, has no obvious LPH for both of its OM-removed sample and kerogen. Based on a comprehensive analysis of the relative data, it is suggested that the nanopores related to OM and clay minerals in the shale were significantly altered owing to the deformation, with a result of the pores being squeezed into the slit-like shape and converted into micropores. This extraordinary pore structure of the shale formed during the deformation process should be the main preservation mechanism of shale gas.