bluuebunny/crossref_metadata_2025 huggingface dataset:
Rho-Kinase Inhibitors for the Treatment of Refractory Diabetic Macular Oedema
Authors: Mateos-Olivares Milagros , García-Onrubia Luis , Valentín-Bravo Fco. Javier , González-Sarmiento Rogelio , Lopez-Galvez Maribel , Pastor J. Carlos , Usategui-Martín Ricardo , Pastor-Idoate Salvador
Published: July 2021

Diabetic macular oedema (DMO) is one of the leading causes of vision loss associated with diabetic retinopathy (DR). New insights in managing this condition have changed the paradigm in its treatment, with intravitreal injections of antivascular endothelial growth factor (anti-VEGF) having become the standard therapy for DMO worldwide. However, there is no single standard therapy for all patients DMO refractory to anti-VEGF treatment; thus, further investigation is still needed. The key obstacles in developing suitable therapeutics for refractory DMO lie in its complex pathophysiology; therefore, there is an opportunity for further improvements in the progress and applications of new drugs. Previous studies have indicated that Rho-associated kinase (Rho-kinase/ROCK) is an essential molecule in the pathogenesis of DMO. This is why the Rho/ROCK signalling pathway has been proposed as a possible target for new treatments. The present review focuses on the recent progress on the possible role of ROCK and its therapeutic potential in DMO. A systematic literature search was performed, covering the years 1991 to 2021, using the following keywords: “rho-Associated Kinas-es”, “Diabetic Retinopathy”, “Macular Edema”, “Ripasudil”, “Fasudil” and “Netarsudil”. Better insight into the pathological role of Rho-kinase/ROCK may lead to the development of new strategies for refractory DMO treatment and prevention.
IGF-1 Haploinsufficiency Causes Age-Related Chronic Cochlear Inflammation and Increases Noise-Induced Hearing Loss
Authors: Celaya Adelaida M. , Rodríguez-de la Rosa Lourdes , Bermúdez-Muñoz Jose M. , Zubeldia José M. , Romá-Mateo Carlos , Avendaño Carlos , Pallardó Federico V. , Varela-Nieto Isabel
Published: July 2021

Insulin-like growth factor 1 (IGF-1) deficiency is an ultrarare syndromic human sensorineural deafness. Accordingly, IGF-1 is essential for the postnatal maturation of the cochlea and the correct wiring of hearing in mice. Less severe decreases in human IGF-1 levels have been associated with other hearing loss rare genetic syndromes, as well as with age-related hearing loss (ARHL). However, the underlying mechanisms linking IGF-1 haploinsufficiency with auditory pathology and ARHL have not been studied. Igf1-heterozygous mice express less Igf1 transcription and have 40% lower IGF-1 serum levels than wild-type mice. Along with ageing, IGF-1 levels decreased concomitantly with the increased expression of inflammatory cytokines, Tgfb1 and Il1b, but there was no associated hearing loss. However, noise exposure of these mice caused increased injury to sensory hair cells and irreversible hearing loss. Concomitantly, there was a significant alteration in the expression ratio of pro- and anti-inflammatory cytokines in Igf1+/− mice. Unbalanced inflammation led to the activation of the stress kinase JNK and the failure to activate AKT. Our data show that IGF-1 haploinsufficiency causes a chronic subclinical proinflammatory age-associated state and, consequently, greater susceptibility to stressors. This work provides the molecular bases to further understand hearing disorders linked to IGF-1 deficiency.
Circulating Cell Biomarkers in Pulmonary Arterial Hypertension: Relationship with Clinical Heterogeneity and Therapeutic Response
Authors: Tura-Ceide Olga , Blanco Isabel , Garcia-Lucio Jéssica , del Pozo Roberto , García Agustín Roberto , Ferrer Elisabet , Crespo Isabel , Rodríguez-Chiaradia Diego A. , Simeon-Aznar Carmen Pilar , López-Meseguer Manuel , Martín-Ontiyuelo Clara , Peinado Víctor I. , Barberà Joan Albert
Published: July 2021

Background: Endothelial dysfunction is central to PAH. In this study, we simultaneously analysed circulating levels of endothelial microvesicles (EMVs) and progenitor cells (PCs) in PAH and in controls, as biomarkers of pulmonary endothelial integrity and evaluated differences among PAH subtypes and as a response to treatment. Methods: Forty-seven controls and 144 patients with PAH (52 idiopathic, 9 heritable, 31 associated with systemic sclerosis, 15 associated with other connective tissue diseases, 20 associated with HIV and 17 associated with portal hypertension) were evaluated. Forty-four patients with scleroderma and 22 with HIV infection, but without PAH, were also studied. Circulating levels of EMVs, total (CD31+CD42b−) and activated (CD31+CD42b−CD62E+), as well as circulating PCs (CD34+CD133+CD45low) were measured by flow cytometry and the EMVs/PCs ratio was computed. In treatment-naïve patients, measurements were repeated after 3 months of PAH therapy. Results: Patients with PAH showed higher numbers of EMVs and a lower percentage of PCs, compared with healthy controls. The EMV/PC ratio was increased in PAH patients, and in patients with SSc or HIV without PAH. After starting PAH therapy, individual changes in EMVs and PCs were variable, without significant differences being observed as a group. Conclusion: PAH patients present disturbed vascular homeostasis, reflected in changes in circulating EMV and PC levels, which are not restored with PAH targeted therapy. Combined measurement of circulating EMVs and PCs could be foreseen as a potential biomarker of endothelial dysfunction in PAH.
Prediction Model for Diagnosis of Kawasaki Disease Using iTRAQ-Based Analysis
Authors: Weng Ken-Pen , Li Sung-Chou , Chien Kuang-Jen , Tsai Kuo-Wang , Kuo Ho-Chang , Hsieh Kai-Sheng , Huang Shih-Hui
Published: July 2021

A quick prediction method may help confirm the diagnosis of Kawasaki disease (KD), and reduce the risk of coronary artery lesions. The purpose of this study was to evaluate potential candidate diagnostic serum proteins in KD using isobaric tagging for relative and absolute quantification (iTRAQ) gel-free proteomics. Ninety two subjects, including 68 KD patients (1.6 ± 1.2 years, M/F 36/32) and 24 fever controls with evident respiratory tract infection (2.1 ± 1.2 years, M/F 13/11) were enrolled. Medical records were reviewed for demographic and laboratory data. The iTRAQ gel-free proteomics was used to screen serum proteins completely and compare the difference between two groups followed by specific validation with ELISA. The candidate proteins and conventional laboratory items were selected for the prediction model of KD diagnosis by support vector machine. Five selected candidate proteins, including protein S100-A8, protein S100-A9, protein S100-A12, neutrophil defensin 1, and alpha-1-acid glycoprotein 1 were identified for developing the prediction model of KD diagnosis. They were used to develop an efficient KD prediction model with an area under receiver operating characteristic (auROC) value of 0.92 (95% confidence interval: 0.84, 0.98). These protein biomarkers were significantly correlated with the conventional laboratory items as follows: C-reactive protein, glutamic pyruvic transaminase, white blood count, platelet, segment and hemoglobin. These conventional laboratory items were used to develop a prediction model of KD diagnosis with an auROC value of 0.88 (95% confidence interval: 0.80, 0.96). Our result demonstrated that the prediction model with combined five selected candidate protein levels may be a good diagnostic tool of KD. Further prediction model with combined six conventional laboratory data is also an acceptable alternative method for KD diagnosis.
Identification and Characterization of Cancer Stem-Like Cells in ALK-Positive Anaplastic Large Cell Lymphoma Using the SORE6 Reporter
Authors: Li Jing , Haque Moinul , Shang Chuquan , Hassan Bardes , Liu Dongzhe , Chen Will , Lai Raymond
Published: July 2021

Transcription factors Sox2 and Oct4 are essential in maintaining the pluripotency of embryonic stem cells and conferring stemness in cancer stem-like (CSL) cells. SORE6, an in-vitro reporter system, was designed to quantify the transcription activity of Sox2/Oct4 and identify CSL cells in non-hematologic cancers. Using SORE6, we identified and enriched CSL cells in ALK-positive anaplastic large cell lymphoma (ALK + ALCL). Two ALK + ALCL cell lines, SupM2 and UCONN-L2, contained approximately 20% of SORE6+ cells, which were purified based on their expression of green fluorescent protein. We then performed functional studies using single-cell clones derived from SORE6− and SORE6+ cells. Compared to SORE6− cells, SORE6+ cells were significantly more chemoresistant and clonogenic in colony-formation assays. Sox2/Oct4 are directly involved in conferring these CSL properties, since the shRNA knockdown of Sox2 in SORE6+ significantly lowered their chemoresistance, while enforced expression of Sox2/Oct4 in SORE6− cells produced opposite effects. Using Western blots, we found that the expression and subcellular localization of Sox2/Oct4 were similar between SORE6− and SORE6+ cells. However, in SORE6+ but not SORE6− cells, Sox2 and Oct4 abundantly bound to a probe containing the SORE6 consensus sequence. c-Myc, previously shown to regulate cancer stemness in ALK + ALCL, regulated the SORE6 activity. In conclusion, SORE6 is useful in identifying/enriching CSL cells in ALK + ALCL.
Development of Indium Titanium Zinc Oxide Thin Films Used as Sensing Layer in Gas Sensor Applications
Authors: Chang Sheng-Po , Yang Ren-Hao , Lin Chih-Hung
Published: July 2021

InTiZnO gas sensors with different oxygen ratios were fabricated by RF sputtering at room temperature. The sensing responses for five different gases, including ethanol, isopropanol (IPA), acetone (ACE), CO, and SO2, were reported. The InTiZnO gas sensor with the MSM (metal–semiconductor–metal) structure generated a higher sensing response when the O2/Ar ratio was increased to 10%. It also revealed high selectivity among these gases and good repeatability. Moreover, the UV light-activated InTiZnO gas sensors were also studied, which could reduce the operating temperature from 300 °C to 150 °C and did not seem to damage the sensing film, demonstrating long-term stability. The high response and selectivity revealed that InTiZnO thin films possess high potential to be applied in gas sensing technology.
Zn-Doped CaP-Based Coatings on Ti–6Al–4V and Ti–6Al–7Nb Alloys Prepared by Magnetron Sputtering: Controllable Biodegradation, Bacteriostatic, and Osteogenic Activities
Authors: Prosolov Konstantin A. , Mitrichenko Dmitrii V. , Prosolov Aleksandr B. , Nikolaeva Olga O. , Lastovka Vladimir V. , Belyavskaya Olga A. , Chebodaeva Valentina A. , Glukhov Ivan A. , Litvinova Larisa S. , Shupletsova Valeria V. , Khaziakhmatova Olga G. , Malashchenko Vladimir V. , Yurova Kristina A. , Shunkin Egor O. , Fedorov Maxim A. , Komkov Andrei R. , Pavlenko Vladimir V. , Anisenya Ilya I. , Sharkeev Yurii P. , Vladescu Alina , Khlusov Igor A.
Published: July 2021

New TiNb-based alloys, such as Ti–6Al–7Nb, are currently being studied around the world as an alternative to other Ti alloys, e.g., instead of Ti–6Al–4V. We conducted a pilot study where thin (approximately 1.2 micron) CaP coatings containing low doses of Zn2+ (0.4–0.8 wt.%) were prepared by the radio frequency magnetron sputtering (RFMS) of Zn-hydroxyapatite (HA) target on Ti–6Al–4V and Ti–6Al–7Nb substrates and investigated their physicochemical properties, in vitro solubility, cytotoxicity, and antibacterial and osteogenic activities. The thickness of the obtained coatings was approximately 1.2–1.3 microns. Zn substitution did not result in roughness or structural or surface changes in the amorphous CaP coatings. The distributions of Ca, P, and Zn were homogeneous across the film thickness as shown by the EDX mapping of these elements. Zn doping of CaP coatings on both types of Ti-based alloys statistically influenced the results of the scratch-test. However, obtained values are satisfactory to use Zn-CaP coatings on biomedical implants. Increased Zn2+ release vs. tapered output of Ca and phosphate ions occurred during 5 weeks of an in vitro immersion test in 0.9% NaCl solution. Ti–6Al–7Nb alloy, unlike Ti–6Al–4V, promoted more linear biodegradation of CaP coatings in vitro. As a result, CaP-based surfaces on Ti–6Al–7Nb, compared with on Ti–6Al–4V alloy, augmented the total areas of Alizarin red staining in a 21-day culture of human adipose-derived mesenchymal stem cells in a statistically significant manner. Moreover, Zn–CaP coatings statistically reduced leukemic Jurkat T cell survival within 48 h of in vitro culture. Along with the higher solubility of the Zn–CaP surface, a greater reduction (4- to 5.5-fold) in Staphylococcus aureus growth was observed in vitro when 7-day extracts of the coatings were added into the microbial culture. Hence, Zn–CaP-coated Ti–6Al–7Nb alloy with controllable biodegradation as prepared by RFMS is a prospective material suitable for bone applications in cases where there is a risk of bacterial contamination with severe consequences, for example, in leukemic patients. Further research is needed to closely investigate the mechanical features and pathways of their solubility and antimicrobial, antitumor, and osteogenic activities.
Antimicrobial Properties of Strontium Functionalized Titanium Surfaces for Oral Applications, A Systematic Review
Authors: Alshammari Hatem , Bakitian Fahad , Neilands Jessica , Andersen Ole Zoffmann , Stavropoulos Andreas
Published: July 2021

The aim of this systematic review was to assess the current scientific evidence of the antimicrobial potential of strontium (Sr) when used to functionalize titanium (Ti) for oral applications. Out of an initial list of 1081 potentially relevant publications identified in three electronic databases (MEDLINE via PubMed, Scopus, and Cochrane) up to 1 February 2021, nine publications based on in vitro studies met the inclusion criteria. The antimicrobial potential of Sr was investigated on different types of functionalized Ti substrates, employing different application methods. Nine studies reported on the early, i.e., 6–24 h, and two studies on the late, i.e., 7–28 days, antimicrobial effect of Sr, primarily against Staphylococcus aureus (S. aureus) and/or Escherichia coli (E. coli). Sr-modified samples demonstrated relevant early antimicrobial potential against S. aureus in three studies; only one of which presented statistical significance values, while the other two presented only the percentage of antimicrobial rate and biofilm inhibition. A relevant late biofilm inhibition potential against S. aureus of 40% and 10%—after 7 and 14 days, respectively—was reported in one study. Combining Sr with other metal ions, i.e., silver (Ag), zinc (Zn), and fluorine (F), demonstrated a significant antimicrobial effect and biofilm inhibition against both S. aureus and E. coli. Sr ion release within the first 24 h was generally low, i.e., below 50 µg/L and 0.6 ppm; however, sustained Sr ion release for up to 30 days, while maintaining up to 90% of its original content, was also demonstrated. Thus, in most studies included herein, Sr-functionalized Ti showed a limited immediate (i.e., 24 h) antimicrobial effect, likely due to a low Sr ion release; however, with an adequate Sr ion release, a relevant antimicrobial effect, as well as a biofilm inhibition potential against S. aureus—but not E. coli—was observed at both early and late timepoints. Future studies should assess the antimicrobial potential of Ti functionalized with Sr against multispecies biofilms associated with peri-implantitis.
Radical Scavenging and Catalytic Activity of Fe-Cu Bimetallic Nanoparticles Synthesized from Ixora finlaysoniana Extract
Authors: Younas Umer , Hassan Syed , Ali Faisal , Hassan Faiza , Saeed Zohaib , Pervaiz Muhammad , Khan Safia , Jannat Fakiha , Bibi Sidra , Sadiqa Ayesha , Ali Zahid , Iqbal Shahid , Ghfar Ayman , Ouladsmane Mohamed , AL-Anazy Murefah , Ali Shafaqat
Published: July 2021

Iron–copper bimetallic nanoparticles (Fe-Cu BNPs) were prepared via a green synthesis route. Ixora finlaysoniana has been used in this study as a capping and stabilizing agent in the modification of Fe-Cu BNPs. As-synthesized BNPs were characterized using different techniques including UV/Vis spectrophotometry, FTIR, XRD and SEM. A particle size analyzer and SEM studies indicated the particle size to be in the range of 50–200 nm. In addition, degradation of MB dye in an aqueous system and radical-scavenging potential in a DPPH assay were also examined using BNPs. Methylene blue dye degradation in 17 min was monitored with UV/Vis spectrophotometry, which exhibited the efficiency of Fe-Cu BNPs. Bimetallic nanoparticles were also found to be efficient in neutralizing DPPH free radicals. Furthermore, kinetic studies of both dye degradation and radical scavenging potential are reported in this article. Subsequently, Fe-Cu BNPs synthesized via a green and sustainable method can be employed for dye degradation and free radical-scavenging activities.
Sensitivity of the Viscous Damping Coefficient of Carbon Fiber in Carbon-Fiber-Reinforced Plastic with Respect to the Fiber Angle
Authors: Kim Chan-Jung
Published: July 2021

The variation in the viscous damping coefficient with the carbon fiber angle can be evaluated using the partial derivatives of the viscous damping coefficient with respect to the resonance frequency and modal damping ratio. However, the direct derivatives of the viscous damping coefficient were not effective solutions to the sensitivity analysis of carbon-fiber-reinforced plastic (CFRP) structures because the viscous damping from the binding matrix was not changed over the carbon fiber angle. If the identified viscous damping coefficients were assumed to be equivalent values from the parallel relationship between the binding matrix and carbon fiber, the relative error of the viscous damping coefficient of carbon fiber between the increased carbon fiber angle and reference angle could be used as the sensitivity index for the viscous damping coefficient of carbon fiber only. The modal parameters, resonance frequency, and modal damping ratio were identified from the experimental modal test of rectangular CFRP specimens for five different carbon fiber angles between 0° and 90°. The sensitivity of the viscous damping coefficient of carbon fiber was determined for two sensitivity indices: the direct derivative of the mass-normalized equivalent viscous damping coefficient and the relative error of the viscous damping coefficient of carbon fiber. The sensitivity results were discussed using the five mode shapes of the CFRP specimen, that is, three bending modes and two twisting modes.
Clinical and Translational Neuroscience: Time for a Change: “What’s Past Is Prologue”
Authors: Bassetti Claudio Lino Alberto
Published: July 2021

The first issue of Clinical and Translational Neuroscience (CTN) (ISSN: 2514-183X) appeared in 2017 [...]
Changes in Physical and Psychological States with Respect to the Gender of Outpatients Receiving Rehabilitation at Geriatric Health Services Facilities during the COVID-19 State of Emergency
Authors: Izawa Kazuhiro P. , Oyama Masataka , Okamoto Keisuke
Published: July 2021

This study was a sub-analysis of 20 consecutive elderly participants who underwent outpatient rehabilitation at a geriatric health services facility from January 2020 to the end of May 2020, based on our previous report. This study aimed to evaluate the longitudinal changes in their physical and psychological states with respect to gender in rehabilitation outpatients between the pre-nationwide (T1) and post-nationwide state of emergency (T2) caused by the Coronavirus disease 2019 (COVID-19). Gait speed (GS), timed up and go (TUG), handgrip strength (HG), and maximum phonation time (MPT) were measured as indices of physical status. The Japanese version of the Apathy Scale and five-level EuroQoL five-dimensional questionnaire (EQ-5D-5L) were used to assess the psychological state. Both states were measured in the male and female groups at T1 and T2 and then were compared. The final analysis was comprised of 13 outpatients. In males, the physical (GS, p = 0.463; TUG, p = 0.600; HG, p = 0.753; and MPT, p = 0.249) and psychological (Apathy Scale, p = 0.891 and EQ-5D-5L, p = 0.249) states did not change significantly between T1 and T2. In the females, the physical (GS, p = 0.600; TUG, p = 0.735; HG, p = 1.000; and MPT, p = 0.310) and psychological (Apathy Scale, p = 0.588 and EQ-5D-5L, p = 0.176) states also did not show significant change between T1 and T2. In both sexes, the continuance of outpatient rehabilitation might be recommended as one activity that can maintain physical and psychological states during a COVID-19-related state of emergency.
Influences of Different Architectures on the Thermodynamic Performance and Network Structure of Aircraft Environmental Control System
Authors: Yang Han , Yang Chunxin , Zhang Xingjuan , Yuan Xiugan
Published: July 2021

The environmental control system (ECS) is one of the most important systems in the aircraft used to regulate the pressure, temperature and humidity of the air in the cabin. This study investigates the influences of different architectures on the thermal performance and network structure of ECS. The refrigeration and pressurization performances of ECS with four different architectures are analyzed and compared by the endoreversible thermodynamic analysis method, and their external and internal responses have also been discussed. The results show that the connection modes of the heat exchanger have minor effects on the performance of ECSs, but the influence of the air cycle machine is obvious. This study attempts to abstract the ECS as a network structure based on the graph theory, and use entropy in information theory for quantitative evaluation. The results provide a theoretical basis for the design of ECS and facilitate engineers to make reliable decisions.
Area Entropy and Quantized Mass of Black Holes from Information Theory
Authors: He Dongshan , Cai Qingyu
Published: July 2021

In this paper, we present a derivation of the black hole area entropy with the relationship between entropy and information. The curved space of a black hole allows objects to be imaged in the same way as camera lenses. The maximal information that a black hole can gain is limited by both the Compton wavelength of the object and the diameter of the black hole. When an object falls into a black hole, its information disappears due to the no-hair theorem, and the entropy of the black hole increases correspondingly. The area entropy of a black hole can thus be obtained, which indicates that the Bekenstein–Hawking entropy is information entropy rather than thermodynamic entropy. The quantum corrections of black hole entropy are also obtained according to the limit of Compton wavelength of the captured particles, which makes the mass of a black hole naturally quantized. Our work provides an information-theoretic perspective for understanding the nature of black hole entropy.
Measuring the Effectiveness of Adaptive Random Forest for Handling Concept Drift in Big Data Streams
Authors: AlQabbany Abdulaziz O. , Azmi Aqil M.
Published: July 2021

We are living in the age of big data, a majority of which is stream data. The real-time processing of this data requires careful consideration from different perspectives. Concept drift is a change in the data’s underlying distribution, a significant issue, especially when learning from data streams. It requires learners to be adaptive to dynamic changes. Random forest is an ensemble approach that is widely used in classical non-streaming settings of machine learning applications. At the same time, the Adaptive Random Forest (ARF) is a stream learning algorithm that showed promising results in terms of its accuracy and ability to deal with various types of drift. The incoming instances’ continuity allows for their binomial distribution to be approximated to a Poisson(1) distribution. In this study, we propose a mechanism to increase such streaming algorithms’ efficiency by focusing on resampling. Our measure, resampling effectiveness (ρ), fuses the two most essential aspects in online learning; accuracy and execution time. We use six different synthetic data sets, each having a different type of drift, to empirically select the parameter λ of the Poisson distribution that yields the best value for ρ. By comparing the standard ARF with its tuned variations, we show that ARF performance can be enhanced by tackling this important aspect. Finally, we present three case studies from different contexts to test our proposed enhancement method and demonstrate its effectiveness in processing large data sets: (a) Amazon customer reviews (written in English), (b) hotel reviews (in Arabic), and (c) real-time aspect-based sentiment analysis of COVID-19-related tweets in the United States during April 2020. Results indicate that our proposed method of enhancement exhibited considerable improvement in most of the situations.
Impact of Institutional Support on Export Performance
Authors: Mata Mário Nuno , Falahat Mohammad , Correia Anabela Batista , Rita João Xavier
Published: July 2021

This paper examines institutional support (financial and marketing support) on export-oriented firms’ performance or so-called born globals. We develop a model to address how financial and marketing support can help young entrepreneurial firms to overcome the liability of newness and smallness in gaining competitive capabilities. Using a quantitative method, data were collected from 217 manufacturers and service sectors in Malaysia, an emerging Southeast Asian market. The results suggest that government assistance in marketing leads to competitive capabilities and export performance; however, financial support neither contributes to competitive capabilities nor export performance. We found the significant role of competitive capabilities as a mediator in enhancing the relationship between marketing support and export performance. Practical implications drawn from this result can be offered as guidelines for the policymakers in supporting young entrepreneurs that lead to competitive capabilities and superior performance.
Exploring Teachers’ Lived Experiences of Cooperative Learning in Ethiopian Higher Education Classrooms: A Phenomenological-Case Study
Authors: Tadesse Tefera , Asmare Aregu , Ware Hashim
Published: July 2021

A growing body of research indicates that teaching is the most important determinant of student learning in higher education (HE). However, HE teachers have a persistent challenge to transform pedagogical practices from a teacher-centered to a student-centered approach. In this study, the authors employed a phenomenological-case study design to examine the teachers’ lived experiences with cooperative learning (CL) pedagogies as applied in the undergraduates’ classrooms in a large public university in Ethiopia. The authors collected the relevant data from two teacher participants through both reflection and a semi-structured interview, along with document analysis of course-related material. The teacher participants felt that their involvement in the CL lessons gave them insight to understand strategies used to implement CL and practical learning opportunities on how to use it as one variant of student-centered teaching methods. As the teacher interviewees suggested, the CL lessons helped them change their mindset from traditional lecture-based teaching to a student-centered approach and transform their pedagogical practices. The results of this study suggest that CL pedagogies offer teachers with professional development opportunities for a meaningful transformation of their roles in HE classrooms. Additionally, the results have important practical implications for many HE institutions (HEIs) and their teachers who work with undergraduate students.
Towards Dynamic Reconfiguration of a Composite Web Service: An Approach Based on QoS Prediction
Authors: Messiaid Abdessalam , Mokhati Farid , Benaboud Rohallah , Salem Hajer
Published: July 2021

Service-oriented architecture provides the ability to combine several web services in order to fulfil a user-specific requirement. In dynamic environments, the appearance of several unforeseen events can destabilize the composite web service (CWS) and affect its quality. To deal with these issues, the composite web service must be dynamically reconfigured. Dynamic reconfiguration may be enhanced by avoiding the invocation of degraded web services by predicting QoS for the candidate web service. In this paper, we propose a dynamic reconfiguration method based on HMM (Hidden Markov Model) states to predict the imminent degradation in QoS and prevent the invocation of partner web services with degraded QoS values. PSO (Particle Swarm Optimization) and SFLA (Shuffled Frog Leaping Algorithm) are used to improve the prediction efficiency of HMM. Through extensive experiments on a real-world dataset, WS-Dream, the results demonstrate that the proposed approach can achieve better prediction accuracy. Moreover, we carried out a case study where we revealed that the proposed approach outperforms several state-of-the-art methods in terms of execution time.
Physical Layer Latency Management Mechanisms: A Study for Millimeter-Wave Wi-Fi
Authors: Marinšek Alexander , Delabie Daan , De Strycker Lieven , Van der Perre Liesbet
Published: July 2021

Emerging applications in fields such as extended reality require both a high throughput and low latency. The millimeter-wave (mmWave) spectrum is considered because of the potential in the large available bandwidth. The present work studies mmWave Wi-Fi physical layer latency management mechanisms, a key factor in providing low-latency communications for time-critical applications. We calculate physical layer latency in an ideal scenario and simulate it using a tailor-made simulation framework, based on the IEEE 802.11ad standard. Assessing data reception quality over a noisy channel yielded latency’s dependency on transmission parameters, channel noise, and digital baseband tuning. Latency in function of the modulation and coding scheme was found to span 0.28–2.71 ms in the ideal scenario, whereas simulation results also revealed its tight bond with the demapping algorithm and the number of low-density parity-check decoder iterations. The findings yielded tuning parameter combinations for reaching Pareto optimality either by constraining the bit error rate and optimizing latency or the other way around. Our assessment shows that trade-offs can and have to be made to provide sufficiently reliable low-latency communication. In good channel conditions, one may benefit from both the very high throughput and low latency; yet, in more adverse situations, lower modulation orders and additional coding overhead are a necessity.
ViolenceNet: Dense Multi-Head Self-Attention with Bidirectional Convolutional LSTM for Detecting Violence
Authors: Rendón-Segador Fernando J. , Álvarez-García Juan A. , Enríquez Fernando , Deniz Oscar
Published: July 2021

Introducing efficient automatic violence detection in video surveillance or audiovisual content monitoring systems would greatly facilitate the work of closed-circuit television (CCTV) operators, rating agencies or those in charge of monitoring social network content. In this paper we present a new deep learning architecture, using an adapted version of DenseNet for three dimensions, a multi-head self-attention layer and a bidirectional convolutional long short-term memory (LSTM) module, that allows encoding relevant spatio-temporal features, to determine whether a video is violent or not. Furthermore, an ablation study of the input frames, comparing dense optical flow and adjacent frames subtraction and the influence of the attention layer is carried out, showing that the combination of optical flow and the attention mechanism improves results up to 4.4%. The conducted experiments using four of the most widely used datasets for this problem, matching or exceeding in some cases the results of the state of the art, reducing the number of network parameters needed (4.5 millions), and increasing its efficiency in test accuracy (from 95.6% on the most complex dataset to 100% on the simplest one) and inference time (less than 0.3 s for the longest clips). Finally, to check if the generated model is able to generalize violence, a cross-dataset analysis is performed, which shows the complexity of this approach: using three datasets to train and testing on the remaining one the accuracy drops in the worst case to 70.08% and in the best case to 81.51%, which points to future work oriented towards anomaly detection in new datasets.
Using Flipped Classroom to Improve the Learning Effectiveness of Digital Logic Courses
Authors: Han Tuan-Yung , Chen Hong-Ren , Lin Hao-Chiang Koong
Published: July 2021

As a student-centered learning model, flipped classroom has been increasingly preferred among educators since it has changed the traditional teacher-centered learning model. This study conducted experiments and observations on the flipped classroom for digital logic courses for first-year students in the electrical engineering department of a junior college in Taiwan. Before each class, these students were required to watch the prescribed lecture video units. In class, students discussed with group members after thinking and completed the teacher’s requirements by collaboration. In addition to conducting the activities of thinking, discussion, collaboration and observation, these students also got to exercise their expression skills through interactive activities during class time. Analyzing the learning effectiveness with the Panel Data Method (PDM), this study, by comparing and statistically analyzing the data collected during the four years between 2016 and 2019, found that students reaped better learning performance with the flipped classroom model, as shown by a rise in both their average grade and the pass rate.
A Review of Reduction Methods of Impact of Common-Mode Voltage on Electric Drives
Authors: Turzyński Marek , Musznicki Piotr
Published: July 2021

In this survey paper, typical solutions that focus on the reduction in negative effects resulting from the common-mode voltage influence in AC motor drive applications are re-examined. The critical effectiveness evaluation of the considered methods is based on experimental results of tests performed in a laboratory setup with an induction machine fed by an inverter. The capacity of a common-mode voltage level reduction and voltage gradient du/dt limitation is discussed to extend motor bearings’ lifetime and increase motor windings’ safety. The characteristic features of the described solutions are compared and demonstrated using laboratory results.
DC Aging Mechanism of Co2O3-Doped ZnO Varistors
Authors: Zhao Xia , Shen Haibin , Guo Men , He Ziming , Li Yupeng , Wen Ran
Published: July 2021

Lowered power loss and asymmetrically electrical parameters are reported in the DC aging of Co2O3-doped ZnO varistors in this paper. Based on the frequency domain dielectric responses of the pristine and degraded samples, the present study explores the roles of point defects in the aging process via dielectric relaxations and their parameters. It is found that breakdown field increased more in the positive direction than the negative direction. Nonlinearity increased in the positive direction, whereas it decreased in the negative direction, and leakage current density increased more in the negative direction than the positive direction. Given the lowest migration energy of Zinc interstitial (Zni, 0.57 eV) and high oxygen ion conductivity in Bi2O3-rich phase, it is speculated that Zni and adsorbed oxygen (Oad) migrate under DC bias, and then change the defect structure and the double Schottky barrier (DSB) at grain boundaries. As a result, the forward-biased barrier height gradually decreases more than the reverse-biased one.
A New Chaotic Artificial Bee Colony for the Risk-Constrained Economic Emission Dispatch Problem Incorporating Wind Power
Authors: Alshammari Motaeb Eid , Ramli Makbul A. M. , Mehedi Ibrahim M.
Published: July 2021

Due to the rapid increase in the consumption of electrical energy and the instability of fossil fuel prices, renewable energy, such as wind power (WP), has become increasingly economically competitive compared to other conventional energy production methods. However, the intermittent nature of wind energy creates certain challenges to the power network operation. The combined economic environmental dispatch (CEED) including WP is one of the most fundamental challenges in power system operation. Within this context, this paper presents a new attempt to solve the probabilistic CEED problem with WP penetration. The optimal WP to be incorporated in the grid is determined in such a way that the system security is within acceptable limits. The system security is described by various fuzzy membership functions in terms of the probability that power balance cannot be met. These membership functions are formulated based on the dispatcher’s attitude. This probabilistic and non-convex CEED problem is solved using a new technique combining chaos theory and artificial bee colony (ABC) technique. In this improved version of ABC (IABC), chaotic maps are used to generate initial solutions, and the random numbers involved in the standard ABC are substituted by chaotic sequences. The effectiveness of IABC is tested on two groups of benchmark functions and practical cases. The impacts of dispatcher’s attitude and risk level are investigated in the simulation section.
Temperature Distribution in the Insulation System of Condenser-Type HV Bushing—Its Effect on Dielectric Response in the Frequency Domain
Authors: Walczak Krzysztof , Gielniak Jaroslaw
Published: July 2021

HV bushings are an important part of the equipment of large power transformers, responsible for their many serious (including catastrophic) failures. Their proper exploitation needs to apply correct and reliable diagnostics, e.g., the use of dielectric response methods, that take into account their specific construction and working conditions. In this article, based on laboratory tests carried out on a real bushing, it has been shown that the significant temperature distribution within its core significantly affects the shape of the dielectric response of its insulation; therefore, the approach to its modeling should be changed. Hence, a new method for interpreting the results, using the so-called the 2XY model, is proposed. Subsequently, based on the measurements made on the insulators in operation, a new modeling method was verified. In conclusion, it can be stated that the 2XY model significantly improves the reliability of the dielectric response analysis, which should be confirmed in the future by tests on withdrawn and revised insulators.
Optimizing Thermal Efficiencies of Double-Pass Cross-Corrugated Solar Air Heaters on Various Configurations with External Recycling
Authors: Ho Chii-Dong , Chang Hsuan , Hsiao Ching-Fang , Lin Yu-Chen
Published: July 2021

The effect of external-recycle operations on the thermal performance of double-pass cross-corrugated solar air heaters (SAH) under different operating conditions was investigated experimentally and theoretically. Additionally, the simultaneous ordinary equations were solved analytically for each proposed configuration. Four recycling types are introduced for improving the solar thermal performance with different external recycle processes, which are expected to enhance the heat transfer coefficient with a convective turbulent flow between the air and the absorber in the present study. Using recycling double-pass operations, two processes were conducted sequentially: air first flowed over the sinusoidal corrugated absorber plate and then flowed back later over the transverse sinusoidal corrugated bottom plate. Improved device performance was achieved due to the doubled heat transfer area over and under the corrugated absorber plate, from which both the sinusoidal cross-corrugated absorber plate and bottom plate enhanced turbulent intensity. Theoretical predictions and experimental results both indicated that the recycle ratio increased with the SAH thermal efficiency for all proposed designs. The results show a higher heat transfer efficiency for the proposed four configurations using wavelike corrugated plates compared to those conducted in single-pass and flat-plate absorber plates with up to a maximum 133% (from 0.301 to 0.703) increment. The optimal device performance was examined for all external-recycle configurations under the same working dimensions and operational conditions. The best configuration for optimal thermal performance was the device that lengthened the air flow pathway and increased the air velocity within the collector; thus, a higher heat transfer rate was accomplished. The evaluation of increments in the power consumption and of the heat-transfer efficiency enhancement together determined the optimal design based on an economic consideration across various configurations of cross-corrugated double-pass devices.
AC vs. DC Distribution Efficiency: Are We on the Right Path?
Authors: Gelani Hasan Erteza , Dastgeer Faizan , Nasir Mashood , Khan Sidra , Guerrero Josep M.
Published: July 2021

The concept of DC power distribution has gained interest within the research community in the past years, especially due to the rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts, wherein a definite verdict is still unavailable. Is DC distribution a more efficient choice as compared to the conventional AC system? A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts are analyzed for their approach toward the system upon which they have performed efficiency studies. Subsequently, the paper proposes a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution.
Beavers, Bugs and Chemistry: A Mammalian Herbivore Changes Chemistry Composition and Arthropod Communities in Foundation Tree Species
Authors: Durben Rachel M. , Walker Faith M. , Holeski Liza , Keith Arthur R. , Kovacs Zsuzsi , Hurteau Sarah R. , Lindroth Richard L. , Shuster Stephen M. , Whitham Thomas G.
Published: July 2021

The North American beaver (Castor canadensis Kuhl) and cottonwoods (Populus spp.) are foundation species, the interactions of which define a much larger community and affect a threatened riparian habitat type. Few studies have tested the effect of these interactions on plant chemistry and a diverse arthropod community. We experimentally examined the impact of beaver foraging on riparian communities by first investigating beaver food preferences for one cottonwood species, Fremont cottonwood (P. fremontii S. Watson), compared to other locally available woody species. We next examined the impact of beaver foraging on twig chemistry and arthropod communities in paired samples of felled and unfelled cottonwood species in northern Arizona (P. fremontii) and southwestern Colorado (narrowleaf cottonwood, P. angustifolia James, and Eastern cottonwood, P. deltoides W. Bartram ex Marshall). Four major patterns emerged: (1) In a cafeteria experiment, beavers chose P. fremontii six times more often than other woody native and exotic species. (2) With two cottonwood species, we found that the nitrogen and salicortin concentrations were up to 45% greater and lignin concentration 14% lower in the juvenile resprout growth of felled trees than the juvenile growth on unfelled trees (six of seven analyses were significant for P. fremontii and four of six were significant for P. angustifolia). (3) With two cottonwood species, arthropod community composition on juvenile branches differed significantly between felled and unfelled trees, with up to 38% greater species richness, 114% greater relative abundance and 1282% greater species diversity on felled trees (six of seven analyses with P. fremontii and four of six analyses with P. angustifolia were significant). The above findings indicate that the highest arthropod diversity is achieved in the heterogenous stands of mixed felled and unfelled trees than in stands of cottonwoods, where beavers are not present. These results also indicate that beaver herbivory changes the chemical composition in 10 out of 13 chemical traits in the juvenile growth of two of the three cottonwood species to potentially allow better defense against future beaver herbivory. (4) With P. deltoides, only one of five analyses in chemistry was significant, and none of the four arthropod community analyses were significant, suggesting that this species and its arthropod community responds differently to beaver. Potential reasons for these differences are unknown. Overall, our findings suggest that in addition to their impact on riparian vegetation, other mammals, birds, and aquatic organisms, beavers also may define the arthropod communities of two of three foundation tree species in these riparian ecosystems.
Is the Consumer Ready for Innovative Fruit Wines? Perception and Acceptability of Young Consumers
Authors: Merlino Valentina Maria , Fracassetti Daniela , Di Canito Alessandra , Pizzi Simona , Borra Danielle , Giuggioli Nicole Roberta , Vigentini Ileana
Published: July 2021

The consumption of traditional wine has decreased in Europe during the last fifteen years. In parallel, new wine alternatives obtained by blending wines and fruit juices or by flavoring wines with artificial or natural flavors have appeared on the market. Recently, an innovative fruit wine obtained by co-fermentation of grape must and kiwi juice has been proposed and its potential of attraction for consumers should be exploited. To assess the potential consumer acceptability and expectations towards this new product, an online choice experiment has been conducted involving a consumer group of young adults (18–35 years old; n = 373). After the data collection, participants were divided into two groups according to whether they had already tasted a fruit wine (neophiles) or had never tasted it (new entries). For each group, the individual’s responses (on wine consumption habits, expectations and willingness to consume and pay a fruit wine) were analyzed through Principal Component Analysis. Different consumption styles and expectation patterns were defined in the two groups. However, in general, neophiles showed consumption patterns based on the evaluation of fruit quality, sales format, alcoholic content and the presence or not of bubbles, not giving importance to the brand. In contrast, new entries’ responses identified consumption patterns driven by the willingness to pay for a new product, the product value for money and packaging features. Differences between the two groups in expectations about the product sensory characteristics also emerged. These findings should contribute to this area of study by integrating environmental, economic and social dimensions and addressing food innovation and sustainability in the fruit and wine chains.