bluuebunny/crossref_metadata_2025 huggingface dataset:
Is It the Same Every Summer for the Euphausiids of the Ross Sea?
Authors: De Felice Andrea , Biagiotti Ilaria , Canduci Giovanni , Costantini Ilaria , Malavolti Sara , Giuliani Giordano , Leonori Iole
Published: May 2022

The pelagic ecosystem in the Ross Sea has one central component that is very important for energy exchanges between upper and lower trophic levels: the Middle Trophic Level. Krill species are the most important and abundant organisms within this level. Several acoustic surveys were conducted in the western Ross Sea over the past 25 years, revealing that Euphausia superba is by far the most abundant species of krill in the Ross Sea during austral summer, and that its core distribution is concentrated in the northern part, bordering the Southern Ocean. Euphausia crsytallorophias, the second most abundant krill species, is more concentrated in the central Ross Sea, generally near the coast. Data on krill biomass were collected in December and January from 1994 to 2016 and analyzed together with key environmental parameters by means of two-way ANOVA in order to explain species behavior and identify possible environmental drivers. Temperature and dissolved oxygen influenced the biomass of both species of krill, while other environmental parameters only affected one species. In conclusion, the biomass of both species has varied over the years, possibly due to a complex synergy of environmental drivers.
Tracing the Evolution of Plant Diversity in Southwestern China
Authors: Su Tao , Spicer Robert A. , Zhou Zhe-Kun
Published: May 2022

Biodiversity hotspots are key regions for understanding the evolutionary history of biodiversity as well as the processes initiating and maintaining it [...]
SARS-CoV-2 Antigen Test Results to Infer Active or Non-Active Virus Replication Status in COVID-19 Patients
Authors: De Angelis Giulia , Menchinelli Giulia , Liotti Flora Marzia , Marchetti Simona , Salustri Alessandro , Vella Antonietta , Santangelo Rosaria , Posteraro Brunella , Sanguinetti Maurizio
Published: May 2022

We used nasopharyngeal swab samples of patients with a symptomatic (n = 82) or asymptomatic (n = 20) coronavirus disease 2019 (COVID-19) diagnosis to assess the ability of antigen detection tests to infer active (potentially transmissible) or inactive (potentially non-transmissible) infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Using the subgenomic RNA (sgRNA) as an active replication marker of SARS-CoV-2, 48 (76.2%), 56 (88.9%), and 63 (100%) of 63 samples with sgRNA positive results tested positive with the SD BIOSENSOR STANDARD Q COVID-19 Ag (Standard Q), the SD BIOSENSOR STANDARD F COVID-19 Ag FIA (Standard F), or the Fujirebio LUMIPULSE G SARS-CoV-2 Ag (Lumipulse) assay, respectively. Conversely, 37 (94.9%), 29 (74.4%), and 7 (17.9%) of 39 samples with sgRNA negative results tested negative with Standard Q, Standard F, or Lumipulse, respectively. Stratifying results by the number of days of symptoms before testing revealed that most antigen positive/sgRNA positive results were among samples tested at 2–7 days regardless of the assay used. Conversely, most antigen negative/sgRNA negative results were among samples tested at 16–30 days only when Standard Q or Standard F were used. In conclusion, based on our findings, a negative antigen test, especially with the Lumipulse assay, or a positive antigen test, especially with the Standard F assay, may suggest, respectively, the absence or presence of replication-competent SARS-CoV-2.
Large Angiomyxoma of the Umbilical Cord-Uncomplicated Rupture of Tumor Membranes at 32 Weeks of Gestation
Authors: Lisovaja Ija , Franckevica Ivanda , Vedmedovska Natalija
Published: May 2022

Background: When a tumor of the umbilical cord is prenatally visualized, it is possible to propose the diagnosis depending on the sonographic appearance of the tumor. Angiomyxoma of the umbilical cord appears as a complex solid-cystic mass that is made of angiomatous component and myxoid stroma. When the tumor is diagnosed, serial ultrasound and doppler examinations are used to monitor the tumor’s size and the overall fetal well-being including doppler investigations and fetal growth. Angiomyxomas are not associated with fetal chromosomal pathologies. The cases of intrauterine rupture and fetal death was described in the literature. Case presentation: A 28 years-old pregnant woman was referred to our clinic for second opinion because of visualized umbilical cord tumor during second trimester ultrasound screening. The tumor gradually increased in size until 34th week of gestation, when the rupture of the cystic component was observed. The fetal doppler studies was normal during the course of pregnancy, we observed decreased AC and decreased estimated fetal weight. At the gestational age of the 37 weeks the labor was induced and heathy male infant was born. Conclusions: For the first time to our knowledge, we demonstrate the case of uncomplicated rupture of the cystic component of the angiomyxoma that lead to the possibility to manage the pregnancy conservatively without any compromise of the fetus.
Transient Polyhydramnios during Pregnancy Complicated with Gestational Diabetes Mellitus: Case Report and Systematic Review
Authors: Preda Agnesa , Ștefan Adela Gabriela , Preda Silviu Daniel , Comănescu Alexandru Cristian , Forțofoiu Mircea-Cătălin , Vladu Mihaela Ionela , Forțofoiu Maria , Moța Maria
Published: May 2022

Polyhydramnios is an obstetrical condition defined as a pathological increase in the amniotic fluid and is associated with a high risk of maternal-fetal complications. Common causes of polyhydramnios include fetal anatomical and genetic abnormalities, gestational diabetes mellitus, and fetal viral infections. We present the case of a 30-year-old Caucasian woman with transient polyhydramnios associated with gestational diabetes mellitus and obstetric complications. The diagnosis was based on the ultrasound assessment of amniotic fluid volume during a common examination at 26 weeks. Two weeks prior, the patient had been diagnosed with gestational diabetes mellitus. After 4 days, the patient was examined, and the amniotic fluid index returned to normal values. At 38 weeks, the patient presented to the emergency room due to lack of fetal active movement. Ultrasound revealed polyhydramnios, the patient was admitted for severe fetal bradycardia, and fetal extraction through emergency cesarian section was performed. Six weeks after birth, the patient underwent an oral glucose tolerance test with normal values, confirming gestational diabetes mellitus. We performed a systematic review of the literature on polyhydramnios, from January 2016 to April 2022, to analyze all recent published cases and identify the most common etiological causes and important aspects related to maternal-fetal outcomes.
Nerve Echogenicity in Polyneuropathies of Various Etiologies—Results of a Retrospective Semi-Automatic Analysis of High-Resolution Ultrasound Images
Authors: Erdmann Anke , Motte Jeremias , Brünger Jil , Grüter Thomas , Gold Ralf , Pitarokoili Kalliopi , Fisse Anna Lena
Published: May 2022

Echogenicity of peripheral nerves in high-resolution ultrasound (HRUS) provides insight into the structural damage of peripheral nerves in various polyneuropathies. The aim of this study was to compare nerve echogenicity in different primarily axonal or demyelinating polyneuropathies to examine the significance of this parameter. Performing semi-automated echogenicity analysis and applying Image J, we retrospectively used HRUS images of 19 patients with critical illness polyneuropathy (CIP), and 27 patients with chemotherapy-induced polyneuropathy (CIN) and compared them to 20 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). The fraction of black representing echogenicity was measured after converting the images into black and white. The nerves of patients with progressive CIDP significantly differed from the hyperechogenic nerves of patients with other polyneuropathies at the following sites: the median nerve at the forearm (p < 0.001), the median nerve at the upper arm (p < 0.004), and the ulnar nerve at the upper arm (p < 0.001). The other polyneuropathies showed no notable differences. Altogether, the comparison of echogenicity between different polyneuropathies supports the assumption that there are differences depending on the genesis of the structural nerve damage. However, these differences are slight, and cannot be used to show clear differences between each polyneuropathy form.
Neonatal Sequential Organ Failure Assessment (nSOFA) Score within 72 Hours after Birth Reliably Predicts Mortality and Serious Morbidity in Very Preterm Infants
Authors: Berka Ivan , Korček Peter , Janota Jan , Straňák Zbyněk
Published: May 2022

The aim of this study was to assess the applicability of the neonatal sequential organ failure assessment score (nSOFA) within 72 h after delivery as a predictor for mortality and adverse outcome in very preterm neonates. Inborn neonates <32 weeks of gestation were evaluated. The nSOFA scores were calculated from medical records in the first 72 h after birth and the peak value was used for analysis. Death or composite morbidity at hospital discharge defined the adverse outcome. Composite morbidity consisted of chronic lung disease, intraventricular haemorrhage ≥grade III, periventricular leukomalacia and necrotizing enterocolitis. Among 423 enrolled infants (median birth weight 1070 g, median gestational age 29 weeks), 27 died and 91 developed composite morbidity. Death or composite morbidity was associated with organ dysfunction as assessed by nSOFA, systemic inflammatory response, and low birthweight. The score >2 was associated with OR 2.5 (CI 1.39–4.64, p = 0.002) for the adverse outcome. Area under the curve of ROC was 0.795 (95% CI = 0.763–0.827). The use of nSOFA seems to be reasonable for predicting mortality and morbidity in very preterm infants. It constitutes a suitable basis to measure the severity of organ dysfunction regardless of the cause.
Translation of a Protease Turnover Assay for Clinical Discrimination of Mucinous Pancreatic Cysts
Authors: Suresh Vallabh , Byers Kaleb , Rajesh Ummadisetti Chinna , Caiazza Francesco , Zhu Gina , Craik Charles S. , Kirkwood Kimberly , Davisson Vincent Jo , Sheik Daniel A.
Published: May 2022

The classification of pancreatic cyst fluids can provide a basis for the early detection of pancreatic cancer while eliminating unnecessary procedures. A candidate biomarker, gastricsin (pepsin C), was found to be present in potentially malignant mucinous pancreatic cyst fluids. A gastricsin activity assay using a magnetic bead-based platform has been developed using immobilized peptide substrates selective for gastricsin bearing a dimeric rhodamine dye. The unique dye structure allows quantitation of enzyme-cleaved product by both fluorescence and surface enhanced Raman spectroscopy (SERS). The performance of this assay was compared with ELISA assays of pepsinogen C and the standard of care, carcinoembryonic antigen (CEA), in the same clinical sample cohort. A retrospective cohort of mucinous (n = 40) and non-mucinous (n = 29) classes of pancreatic cyst fluid samples were analyzed using the new protease activity assay. For both assay detection modes, successful differentiation of mucinous and non-mucinous cyst fluid was achieved using 1 µL clinical samples. The activity-based assays in combination with CEA exhibit optimal sensitivity and specificity of 87% and 93%, respectively. The use of this gastricsin activity assay requires a minimal volume of clinical specimen, offers a rapid assay time, and shows improvements in the differentiation of mucinous and non-mucinous cysts using an accurate standardized readout of product formation, all without interfering with the clinical standard of care.
Intelligent Diagnosis and Classification of Keratitis
Authors: Alquran Hiam , Al-Issa Yazan , Alsalatie Mohammed , Mustafa Wan Azani , Qasmieh Isam Abu , Zyout Ala’a
Published: May 2022

A corneal ulcer is an open sore that forms on the cornea; it is usually caused by an infection or injury and can result in ocular morbidity. Early detection and discrimination between different ulcer diseases reduces the chances of visual disability. Traditional clinical methods that use slit-lamp images can be tiresome, expensive, and time-consuming. Instead, this paper proposes a deep learning approach to diagnose corneal ulcers, enabling better, improved treatment. This paper suggests two modes to classify corneal images using manual and automatic deep learning feature extraction. Different dimensionality reduction techniques are utilized to uncover the most significant features that give the best results. Experimental results show that manual and automatic feature extraction techniques succeeded in discriminating ulcers from a general grading perspective, with ~93% accuracy using the 30 most significant features extracted using various dimensionality reduction techniques. On the other hand, automatic deep learning feature extraction discriminated severity grading with a higher accuracy than type grading regardless of the number of features used. To the best of our knowledge, this is the first report to ever attempt to distinguish corneal ulcers based on their grade grading, type grading, ulcer shape, and distribution. Identifying corneal ulcers at an early stage is a preventive measure that reduces aggravation and helps track the efficacy of adapted medical treatment, improving the general public health in remote, underserved areas.
IBD Monitor: Romanian National Mobile Application for Inflammatory Bowel Disease Personalized Treatment and Monitoring
Authors: Oancea Carmen-Nicoleta , Statie Răzvan-Cristian , Gheonea Dan-Ionuț , Ciurea Tudorel , Șerbănescu Mircea-Sebastian , Streba Costin-Teodor
Published: May 2022

Background: In the last 30 years, we have seen an increase in the incidence of inflammatory bowel disease (IBD). Most cases are diagnosed in the 2nd and 3rd decades of life, a population group that is most familiar with the latest innovations in technology. Patients want to obtain more information about their disease and have complete control over the pathology, while reducing physical meetings with their doctor. Starting from these ideas, the present study aimed to develop a mobile application (app) to support IBD patients on symptoms/events reporting and on treatment administration monitoring. Methods: A multidisciplinary team was created to document and develop the app requirements and design its functionality. The app was beta-tested by several IBD patients. Their feedback was used to further refine the app. Results: We developed connected apps for both smartphones and smartwatches, with dedicated sections for event reporting and medication administration reminders/reporting. Conclusions: The development of apps dedicated to IBD patients is still in early progress. By creating this app, we aim to improve the evolution and compliance of IBD patients and to obtain new information that will have a beneficial impact on the management of these patients and open the door for personalized medicine.
Morphological Analysis of the Tibial Slope in 720 Adult Knee Joints
Authors: Meier Marc-Pascal , Hochrein Yara , Saul Dominik , Seitz Mark-Tilmann , Klockner Friederike Sophie , Lehmann Wolfgang , Hawellek Thelonius
Published: May 2022

Background: The tibial slope (TS) defines the posterior inclination of the tibial plateau (TP). The “individual physiological” TS plays a crucial role in knee-joint stability and should be taken into account in knee-joint surgery. The aim of this study was to analyse the specific morphology of the TS for the medial (med) and lateral (lat) TP in relation to patient characteristics and the measurement method. Methods: In this retrospective study, MRI images of knee joints from 720 patients (mean age: 49.9 years [±17.14]) were analysed. The TS was assessed using two established methods according to Hudek (TSH) and Karimi (TSK) for the med and lat TP and gender/side specificity was analysed. Results: TSH for the med and lat TP showed significantly (p < 0.001) different values compared to TSK (TSKmed: 2.6° (±3.7), TSHmed: 4.8° (±3.5); TSKlat: 3.0° (±4.0), TSHlat: 5.2° (±3.9)). The angles of the lat TP were significantly higher than those of the med TP (TSK: p < 0.001; TSH: p = 0.002). Females showed a higher med and lat TS compared to males (p < 0.001). Conclusions: The measurement method has an influence on the values of the TS in knee-joint MRIs. The TS is significantly different for the med and lat TP regardless of the measurement method. There are gender-specific differences for the TS.
Detecting Abnormal Axillary Lymph Nodes on Mammograms Using a Deep Convolutional Neural Network
Authors: Abel Frederik , Landsmann Anna , Hejduk Patryk , Ruppert Carlotta , Borkowski Karol , Ciritsis Alexander , Rossi Cristina , Boss Andreas
Published: May 2022

The purpose of this study was to determine the feasibility of a deep convolutional neural network (dCNN) to accurately detect abnormal axillary lymph nodes on mammograms. In this retrospective study, 107 mammographic images in mediolateral oblique projection from 74 patients were labeled to three classes: (1) “breast tissue”, (2) “benign lymph nodes”, and (3) “suspicious lymph nodes”. Following data preprocessing, a dCNN model was trained and validated with 5385 images. Subsequently, the trained dCNN was tested on a “real-world” dataset and the performance compared to human readers. For visualization, colored probability maps of the classification were calculated using a sliding window approach. The accuracy was 98% for the training and 99% for the validation set. Confusion matrices of the “real-world” dataset for the three classes with radiological reports as ground truth yielded an accuracy of 98.51% for breast tissue, 98.63% for benign lymph nodes, and 95.96% for suspicious lymph nodes. Intraclass correlation of the dCNN and the readers was excellent (0.98), and Kappa values were nearly perfect (0.93–0.97). The colormaps successfully detected abnormal lymph nodes with excellent image quality. In this proof-of-principle study in a small patient cohort from a single institution, we found that deep convolutional networks can be trained with high accuracy and reliability to detect abnormal axillary lymph nodes on mammograms.
Ultrasound-Guided Trans-Uterine Cavity Core Needle Biopsy of Uterine Myometrial Tumors to Differentiate Sarcoma from a Benign Lesion—Description of the Method and Review of the Literature
Authors: Stukan Maciej , Rutkowski Piotr , Smadja Jeremy , Bonvalot Sylvie
Published: May 2022

Uterine sarcomas are rare, aggressive tumors with poor prognosis that can be further negatively affected by inadequate surgical approaches such as morcellation. There are no clinical and radiologic criteria for differentiating leiomyoma from malignant uterine tumors. However, some ultrasonography and magnetic resonance imaging findings may be informative. We present a technique of ultrasound-guided trans-uterine cavity (UG-TUC) core needle biopsy for uterine lesions. As the procedure is an in-organ biopsy, there is no risk of needle canal contamination. The technique also enables the biopsy of lesions inaccessible by the transvaginal tru-cut biopsy. The core needle of the automatic biopsy system is inserted via the cervical canal into the uterine cavity and is directed and activated at the myometrial lesion under ultrasound control. The standard local treatment of localized uterine sarcomas is en bloc total hysterectomy; for fibroids, there are multiple options including conservative management or tumorectomy and tumor morcellation using minimally invasive techniques. Fragmentation of the sarcoma significantly worsens oncologic outcomes and should therefore be avoided. The UG-TUC core needle biopsy of uterine lesions can complement imaging to obtain sufficient material for histologic and molecular analyses of suspected or undetermined lesions, thus facilitating treatment planning and decreasing the risk of unsuspected sarcomas.
Mission Chain Driven Unmanned Aerial Vehicle Swarms Cooperation for the Search and Rescue of Outdoor Injured Human Targets
Authors: Cao Yusen , Qi Fugui , Jing Yu , Zhu Mingming , Lei Tao , Li Zhao , Xia Juanjuan , Wang Jianqi , Lu Guohua
Published: May 2022

A novel cooperative strategy for distributed unmanned aerial vehicle (UAV) swarms with different functions, namely the mission chain-driven unmanned aerial vehicle swarms cooperation method, is proposed to allow the fast search and timely rescue of injured human targets in a wide-area outdoor environment. First, a UAV-camera unit is exploited to detect the suspected human target combined with improved deep learning technology. Then, the target location information is transferred to a self-organizing network. Then, the special bio-radar-UAV unit was released to recheck the survivals through a respiratory characteristic detection algorithm. Finally, driven by the location and vital sign status of the injured, a nearby emergency-UAV unit will perform corresponding medical emergency missions, such as dropping emergency supplies. Experimental results show that this strategy can identify the human targets autonomously from the outdoor environment effectively, and the target detection, target sensing, and medical emergency mission chain is completed successfully relying on the cooperative working mode, which is meaningful for the future search-rescue mission of outdoor injured human targets.
Symplectic Radon Transform and the Metaplectic Representation
Authors: de Gosson Maurice A.
Published: May 2022

We study the symplectic Radon transform from the point of view of the metaplectic representation of the symplectic group and its action on the Lagrangian Grassmannian. We give rigorous proofs in the general setting of multi-dimensional quantum systems. We interpret the Radon transform of a quantum state as a generalized marginal distribution for its Wigner transform; the inverse Radon transform thus appears as a “demarginalization process” for the Wigner distribution.
Postural Complexity during Listening in Young and Middle-Aged Adults
Authors: Napoli Charles Dane , Helfer Karen S. , van Emmerik Richard E. A.
Published: May 2022

Postural behavior has traditionally been studied using linear assessments of stability (e.g., center of pressure ellipse area). While these assessments may provide valuable information, they neglect the nonlinear nature of the postural system and often lead to the conflation of variability with pathology. Moreover, assessing postural behavior in isolation or under otherwise unrealistic conditions may obscure the natural dynamics of the postural system. Alternatively, assessing postural complexity during ecologically valid tasks (e.g., conversing with others) may provide unique insight into the natural dynamics of the postural system across a wide array of temporal scales. Here, we assess postural complexity using Multiscale Sample Entropy in young and middle-aged adults during a listening task of varying degrees of difficulty. It was found that middle-aged adults exhibited greater postural complexity than did young adults, and that this age-related difference in postural complexity increased as a function of task difficulty. These results are inconsistent with the notion that aging is universally associated with a loss of complexity, and instead support the notion that age-related differences in complexity are task dependent.
Outage Performance of Wireless Powered Decode-and-Forward Relaying Networks in Rician Fading
Authors: Zhang Zhifei , Dong Peng , Tan Xinlu , Li Yaping , Xiong Ke
Published: May 2022

This paper investigates the outage performance of simultaneous wireless information and power transfer (SWIPT)-enabled relay networks with the decode-and-forward relaying protocol, where the effect of the energy triggering threshold at the relay on the system performance is considered. The closed-form expressions of the system outage probability and throughput are derived in Rician channel fading. Monte Carlo Simulation method is used to verify the accuracy of the derived closed-form expressions. The effects of some system parameters on the system performances are discussed via simulations, which show that the system outage probability increases with the increase of the minimum transmission rate required by the users and also decreases with the increase of the energy conversion efficiency. Besides, the system throughput increaseswith the increment of the transmit power of the source node, as well as the energy conversion efficiency. Additionally, the outage performance of the system with the equal two-hop distance is better than that of the system with unequal two-hop distance.
Inter- and Intra-Modal Contrastive Hybrid Learning Framework for Multimodal Abstractive Summarization
Authors: Li Jiangfeng , Zhang Zijian , Wang Bowen , Zhao Qinpei , Zhang Chenxi
Published: May 2022

Internet users are benefiting from technologies of abstractive summarization enabling them to view articles on the internet by reading article summaries only instead of an entire article. However, there are disadvantages to technologies for analyzing articles with texts and images due to the semantic gap between vision and language. These technologies focus more on aggregating features and neglect the heterogeneity of each modality. At the same time, the lack of consideration of intrinsic data properties within each modality and semantic information from cross-modal correlations result in the poor quality of learned representations. Therefore, we propose a novel Inter- and Intra-modal Contrastive Hybrid learning framework which learns to automatically align the multimodal information and maintains the semantic consistency of input/output flows. Moreover, ITCH can be taken as a component to make the model suitable for both supervised and unsupervised learning approaches. Experiments on two public datasets, MMS and MSMO, show that the ITCH performances are better than the current baselines.
Study on Hydrate Production Behaviors by Depressurization Combined with Brine Injection in the Excess-Water Hydrate Reservoir
Authors: Zeng Haopeng , Zhang Yu , Zhang Lei , Chen Zhaoyang , Li Xiaosen
Published: May 2022

Depressurization combined with brine injection is a potential method for field production of natural gas hydrate, which can significantly improve production efficiency and avoid secondary formation of hydrate. In this work, the experiments of hydrate production using depressurization combined with brine injection from a simulated excess-water hydrate reservoir were performed, and the effects of NaCl concentration on hydrate decomposition, temperature change, and heat transfer in the reservoir were investigated. The experimental results indicate that there is little gas production during depressurization in a excess-water hydrate reservoir, and the gas dissociated from hydrate is trapped in pores of sediments. The high-water production reduces the final gas recovery, which is lower than 70% in the experiments. The increasing NaCl concentration only effectively promotes gas production rate in the early stage. The final cumulative gas production and average gas production rate have little difference in different experiments. The NaCl concentration of the produced water is significantly higher than that which is in contact with hydrate in the sediments because the water produced by hydrate decomposition exists on the surface of undissociated hydrate. The high concentration of NaCl in the produced water from the reactor significantly reduces the promoting effect and efficiency of NaCl solution on hydrate decomposition. The injection of NaCl solution decreases the lowest temperature in sediments during hydrate production, and increases the sensible heat and heat transfer from environment for hydrate decomposition. The changes of temperature and resistance effectively reflect the distribution of the injected NaCl solution in the hydrate reservoir.
Socio-Economic and Environmental Implications of Bioenergy Crop Cultivation on Marginal African Drylands and Key Principles for a Sustainable Development
Authors: Varela Pérez Paola , Greiner Beatrice E. , von Cossel Moritz
Published: May 2022

Africa has been a hotspot for the development of food and bioenergy crop cultivation since the 2000s, leading to systematic challenges towards its ability to become a bioeconomy. To reduce land-use conflicts with food crop cultivation, marginal African drylands (MADs) are proposed for sustainable bioenergy cropping systems (BCSs). This study reviews the foremost socio-economic and environmental challenges for BCSs on MADs, and the development of key principles for minimizing adverse outcomes towards a sustainable bioeconomy. Socio-economic prosperity in Africa depends on several systematic solutions, and BCSs that are based on perennial bioenergy crops are promising strategies as they provide a renewable and sustainable energy source for rural areas. However, critical multidimensional challenges such as poverty, food security, gender equality, access to energy, and environmental impact must also be considered to ensure long-term sustainability. This review argues for more transparent land sales/usage (considering the agricultural work of women) and more perennial bioenergy crops. In this context, key principles were derived for a people-centered bottom-up approach that is considered fundamental to ensure the sustainable development of BCSs on MADs in the future.
Multiantenna-Cognitive-Radio-Based Blind Spectrum Sensing under Correlated Signals and Unequal Signal and Noise Powers
Authors: dos Santos Costa Lucas , Alves Fátima Sayury Queralt Queda , de Souza Rausley Adriano Amaral
Published: May 2022

Adopting cognitive radios (CRs) having multiple antennas in blind non-cooperative and cooperative spectrum sensing (CSS) under fading channels has gained attention due to higher detection performances provided by the spatial diversity gain of multi-sensors in different geographical locations and lower complexity, respectively. However, most studies do not consider sensing scenarios of more practical significance: for example, sometimes adopting only uncalibrated antenna arrays and sometimes only correlated signals at antenna arrays of CRs, but almost always, none of these impairments. Therefore, this paper studies these combined impairments on the performances of two blind techniques in centralized CSS with decision fusion (DF) and data fusion for different numbers of CRs and antennas per CR, both under frequency selective fading channels. One is the circular folding cooperative power spectral density split cancellation (CFCPSC), and the other is the generalized likelihood ratio test (GLRT). Extensive numerical results show, for instance, that with sample fusion (SF) and calibrated antennas, GLRT outperforms CFCPSC independently of correlation, numbers of antennas, or CRs. However, uncalibrated antennas severely penalize GLRT while surprisingly benefiting CFCPSC. Correlation is detrimental to GLRT and CFCPSC with SF but may help CFCPSC in DF and GLRT in DF or eigenvalue fusion. Generally, CFCPSC outperforms GLRT.
A Systematic Review of the Applications of Multi-Criteria Decision Aid Methods (1977–2022)
Authors: Basílio Marcio Pereira , Pereira Valdecy , Costa Helder Gomes , Santos Marcos , Ghosh Amartya
Published: May 2022

Multicriteria methods have gained traction in academia and industry practices for effective decision-making. This systematic review investigates and presents an overview of multi-criteria approaches research conducted over forty-four years. The Web of Science (WoS) and Scopus databases were searched for papers on multi-criteria methods with titles, abstracts, keywords, and articles from January 1977 to 29 April 2022. Using the R Bibliometrix tool, the bibliographic data was evaluated. According to this bibliometric analysis, in 131 countries over the past forty-four years, 33,201 authors have written 23,494 documents on multi-criteria methods. This area’s scientific output increases by 14.18 percent every year. China has the highest percentage of publications at 18.50 percent, followed by India at 10.62 percent and Iran at 7.75 percent. Islamic Azad University has the most publications with 504, followed by Vilnius Gediminas Technical University with 456 and the National Institute of Technology with 336. Expert Systems with Applications, Sustainability, and the Journal of Cleaner Production are the top journals, accounting for over 4.67 percent of all indexed works. In addition, E. Zavadskas and J. Wang have the most papers in the multi-criteria approaches sector. AHP, followed by TOPSIS, VIKOR, PROMETHEE, and ANP, is the most popular multi-criteria decision-making method among the ten nations with the most publications in this field. The bibliometric literature review method enables researchers to investigate the multi-criteria research area in greater depth than the conventional literature review method. It allows a vast dataset of bibliographic records to be statistically and systematically evaluated, producing insightful insights. This bibliometric study is helpful because it provides an overview of the issue of multi-criteria techniques from the past forty-four years, allowing other academics to use this research as a starting point for their studies.
Multiplication and Accumulation Co-Optimization for Low Complexity FIR Filter Implementation
Authors: Rao Chaolin , Lou Xin
Published: May 2022

In multiplierless finite impulse response (FIR) filters, the product accumulation block (PAB) could be the major contributor to hardware complexity, especially for high-order filters. In this paper, an optimization scheme where the constant multiplication block and the PAB are jointly optimized at the bit-level is proposed to minimize the hardware complexity. In the proposed joint optimization, the multiple constant multiplications (MCM) block is rearranged into several MCM sub-blocks. The products are summed locally before accumulation to reduce the word-length of the structural adders. It is shown that the symmetric property of linear phase FIR filters can be utilized in some cases to further reduce the complexity of the constant multiplications. Quantitative analyses are also presented to study the relationship between the optimum group size and the coefficient values as well as the filter orders. It is shown that there is no fixed optimum structure for filters with different coefficient word-lengths and filter orders, and each filter needs to be optimized specifically to achieve the minimum hardware complexity. Implementation results are presented to validate the effectiveness of the proposed method.
A 1/f Noise Detection Method for IGBT Devices Based on PSO-VMD
Authors: Wu Jie , Chen Xiao-juan , Zhu Mei-yue
Published: May 2022

The generation of 1/f noise is closely related to the quality defects of IGBT devices. In the process of detecting single-tube noise of IGBT, thermal noise and shot noise show obvious white noise characteristics in the low-frequency range. This paper investigates how to accurately detect the 1/f noise under strong white noise, and thus proposes a particle swarm optimization method known as variational mode decomposition. First, the particle swarm optimization algorithm was used twice to search the optimal parameter combination between the penalty parameter and the decomposition modulus of the VMD model. Then, the parameters of the variational mode decomposition algorithm were set in optimal parameter combination. The frequency center and bandwidth of each IMF component were determined by continuous iteration in the variational framework. Finally, the 1/f noise signal was adaptively separated from background noise. Extensive experimental investigations carried out under different signal-to-noise ratios, compared with the optimal wavelet denoising algorithm, revealed that the PSO-VMD algorithm improved the signal-to-noise ratio by 6.6%, 16.82%, and 42.48%, whereas the mean square error is reduced by 7.12%, 19.80%, and 33.76%.
Research of a Six-Pole Active Magnetic Bearing System Based on a Fuzzy Active Controller
Authors: Ma Zhihao , Liu Gai , Liu Yichen , Yang Zhaocheng , Zhu Huangqiu
Published: May 2022

Magnetic bearings have a series of excellent qualities, such as no friction and abrasions, high speed, high accuracy, and so on, which have fundamentally innovated traditional forms of support. In order to solve the problems of the large volume, low power density and high coupling coefficient of three-pole magnetic bearings, a six-pole AC active magnetic bearing is designed. Firstly, the basic structure and working principle of a two-degree-of-freedom (2-DOF) six-pole active magnetic bearing is introduced. Secondly, a suspension force modeling method of a 2-DOF AC active magnetic bearing based on the Maxwell tensor method is proposed, and the mathematical model of active magnetic bearing is established. Considering the fact that AC active magnetic bearing is essentially a nonlinear system, a fuzzy active disturbance rejection control (ADRC) method is designed based on fuzzy control and ADRC theory. Its control algorithm and control block diagram are given, and the fuzzy ADRC method is simulated and verified. Finally, the control block diagram of an experimental system based on the 2-DOF six-pole active magnetic bearing is given, and the experimental platform is constructed. The experimental results show that the mechanical and magnetic circuit structure of the 2-DOF six-pole active magnetic bearing is reasonable, and the fuzzy controllers can realize the stable suspension of the rotor.
Down-Hole Electromagnetic Heating of Deep Aquifers for Renewable Energy Storage
Authors: Almeida Samuel O. de , Chapiro Grigori , Zitha Pacelli L. J.
Published: May 2022

Electromagnetic (EM) heating is an emerging method for storing renewable energy, such as photovoltaic solar and wind electric power, into aquifers. We investigate how the captured energy increases the temperature of a prototypical deep aquifer for a six-month period and then to which extent the stored energy can be recovered during the consecutive six months. Water injected at a constant flow rate is simultaneously heated using a high-frequency electromagnetic microwave emitter operating at the water natural resonance frequency of 2.45 GHz. The coupled reservoir flow and EM heating are described using Darcy’s and the energy balance equations. The latter includes a source term accounting for the EM wave propagation and absorption, modeled separately using Maxwell’s equations. The equations are solved numerically by the Galerkin least-squares finite element method. The approach was validated using EM-heating input data obtained from controlled laboratory experiments and then was applied to the aquifer. We found that after six years of alternate storage and recovery, up to 77% of the injected energy is recovered when considering realistic heat losses estimated from field data. Even when heat losses are increased by a factor of two, up to 69% of the injected energy is recovered in this case. This shows that down-hole EM heating is a highly effective method for storing renewable energies, capable of helping to solve their inherent intermittency.
Effect of Combined Particle Size Reduction and Fe3O4 Additives on Biogas and Methane Yields of Arachis hypogea Shells at Mesophilic Temperature
Authors: Olatunji Kehinde O. , Madyira Daniel M. , Ahmed Noor A. , Ogunkunle Oyetola
Published: May 2022

Enzymatic hydrolysis of lignocellulose materials has been identified as the rate-limiting step during anaerobic digestion. The application of pretreatment techniques can influence the biodegradability of lignocellulose substrate. This study combined Fe3O4 nanoparticles, which serve as a heterogeneous catalyst during anaerobic digestion, with different particle sizes of Arachis hypogea shells. Batch anaerobic digestion was set up at mesophilic temperature for 35 days. The results showed that 20 mg/L Fe3O4 additives, as a single pretreatment, significantly influence biogas and methane yields with an 80.59 and 106.66% increase, respectively. The combination of 20 mg/L Fe3O4 with a 6 mm particle size of Arachis hypogea shells produced the highest cumulative biogas yield of 130.85 mL/gVSadded and a cumulative methane yield of 100.86 mL/gVSadded. This study shows that 20 mg/L of Fe3O4 additive, combined with the particle size pretreatment, improved the biogas and methane yields of Arachis hypogea shells. This result can be replicated on the industrial scale to improve the energy recovery from Arachis hypogea shells.
Experimental Study of Influence of Core Wettability on Imbibition Properties
Authors: Feng Xuegang , Yue Xiang’an , An Weiqing , Zou Jirui
Published: May 2022

Through new core wettability simulation technology and the single-sided unidirectional imbibition experimental method, the influence of core wettability on oil imbibition characteristics was studied by using artificial cores with wettability index in the range of −0.9~0.95. Results show that for the cores with permeability from ultra-low to medium–high, the imbibition time shows a monotonically decreasing law with the increase in the wettability index. In the weak water-wet range, the imbibition time increases significantly with the weakening of water-wet. Oil imbibition rate goes up with the increase in wettability index. In the strong water-wet range, the imbibition rate will change significantly with wettability. In the water-wet zone, there is a positive correlation between imbibition oil limit recovery and wettability index, according to which a power exponent model of them is established. The imbibition–displacement ratio, which characterizes the contribution rate of oil recovery by imbibition to that by waterflooding, is also positively correlated with the wettability index. In addition, imbibition–displacement ratios of extra-low permeability cores are very close to that of medium–high permeability cores. According to the analysis of the research results, compared with the strongly water-wet oil layer, the weakly water-wet oil layer with a wettability index of 0–0.5 has a greater contribution to oil recovery by using the enhanced imbibition method.
Machine Learning for Solar Resource Assessment Using Satellite Images
Authors: Ordoñez Palacios Luis Eduardo , Bucheli Guerrero Víctor , Ordoñez Hugo
Published: May 2022

Understanding solar energy has become crucial for the development of modern societies. For this reason, significant effort has been placed on building models of solar resource assessment. Here, we analyzed satellite imagery and solar radiation data of three years (2012, 2013, and 2014) to build seven predictive models of the solar energy obtained at different altitudes above sea level. The performance of four machine learning algorithms was evaluated using four evaluation metrics, MBE, R2, RMSE, and MAPE. Random Forest showed the best performance in the model with data obtained at altitudes below 800 m.a.s.l. The results achieved by the algorithm were: 4.89, 0.82, 107.25, and 41.08%, respectively. In general, the differences in the results of the machine learning algorithms in the different models were not very significant; however, the results provide evidence showing that the estimation of solar radiation from satellite images anywhere on the planet is feasible.
An Ecological, Power Lean, Comprehensive Marketing Evaluation System Based on DEMATEL–CRITIC and VIKOR: A Case Study of Power Users in Northeast China
Authors: Gao Xiying , Guan Yan , Sun Dianjia , Liu Li , Yang Jiaxuan , Wang Zhibin , Guo Ziwei , Wang Yue , Gong Gangjun
Published: May 2022

The reduction of carbon emissions in the power industry will play a vital role in global decarbonization. The power industry has three main strategies to achieve this reduction in emissions: to implement lean marketing strategies that effectively target users of power and encourage them to adopt decarbonizing technologies and services; to optimize the efficiency of these users of power; and to improve the efficiency of renewable energy sources. This paper establishes a comprehensive evaluation system of indexed data from power industry customers for the development of lean marketing strategies. This system evaluates indexes derived from customer data on renewable energy sources, carbon emissions, energy efficiency, and customer credit. It adopts the DEMATEL–CRITIC combination weight assignment and VIKOR method for system evaluation and conducts simulation experiments on customer data in a region of Northeastern China to give an example of how this method could be applied in practice to lean marketing. The results show that the evaluation system proposed in this paper can govern the lean marketing decision-making of power sales enterprises.
Advanced Distributed Cooperative Secondary Control of Islanded DC Microgrids
Authors: Aluko Anuoluwapo , Buraimoh Elutunji , Oni Oluwafemi Emmanuel , Davidson Innocent Ewean
Published: May 2022

In an islanded DC microgrid with multiple distributed generators (DGs), the droop control is employed to realize proportional current sharing among the DGs in the microgrid. The action of the droop control causes a deviation in the DC bus voltage which is exacerbated by the line impedance between the DG and the DC bus. In this paper, an advanced distributed secondary control scheme is proposed to simultaneously achieve accurate voltage regulation and cooperative current sharing in the islanded DC microgrid system. The proposed distributed secondary controller is introduced in the cyber layer of the system, and each controller shares information with neighbouring controllers via a communication network. The distributed technique maintains the reliability of the overall system if some part of the communication link fails. The proposed controller uses the type-II fuzzy logic scheme to adaptively select the secondary control parameters for an improved response of the controller. The sufficient conditions to guarantee the stability of the proposed controller are derived using the Lyapunov method. Comprehensive tests under different operating scenarios are conducted to demonstrate the robustness of the proposed control scheme.
Effect of Comb-Type Copolymers on the Non-Isothermal Crystallization Behavior of Paraffin in Methyl Ethyl Ketone (MEK)–Toluene Dewaxing
Authors: Xiong Ying , Nie Xinyao , Wang Zheng , Li Hongyang , Song Yueqin , Wang Jinan , Zhou Xiaolong , Chen Lifang
Published: May 2022

Two comb-type copolymers were synthesized by modifications of the maleic anhydride-α-octadecene copolymer with aniline (AMAC) and with phenethylamine (EMAC), respectively. The effects of AMAC and EMAC on the non-isothermal crystallization kinetics of the MEK–toluene dewaxing process were comparatively investigated. The results showed that, under the optimum process conditions, the addition of 100 ppm AMAC or EMAC could increase the yield of dewaxed oil (DWO) from 67.21% to 70.87% or 69.90%, respectively, and increase the filtration rate by 80% and 70%, respectively. The non-isothermal crystallization kinetics analysis showed that the crystallization process conformed to Mo’s equation, and the addition of AMAC and EMAC slowed down the crystallization rate of paraffin. The polarizing light microscope observations revealed that the addition of AMAC promoted the formation of snow flower-like crystals, and the EMAC addition led to the crystals having longer rods with a relatively complete morphology. This work provided useful experimental data for a better understanding of the roles of comb-type copolymer additives in the MEK–toluene dewaxing process.