bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting the Roots of Recurrence: New Strategies for Eliminating Therapy-Resistant Breast Cancer Stem Cells
Authors: Dahn Margaret L. , Marcato Paola
Published: December 2020

Cancer stem cells (CSCs) are functionally defined in our laboratories by their impressive tumor-generating and self-renewal capacity; clinically, CSCs are of interest because of their enhanced capacity to evade conventional therapies [...]
Connexins and cAMP Cross-Talk in Cancer Progression and Metastasis
Authors: Chen Chang-Xu , Luo Kai-Jun , Yang Jia-Peng , Huang Yun-Chao , Cardenas Eduardo R. , Nicholson Bruce J. , Jiang Jean X.
Published: December 2020

Connexin-containing gap junctions mediate the direct exchange of small molecules between cells, thus promoting cell–cell communication. Connexins (Cxs) have been widely studied as key tumor-suppressors. However, certain Cx subtypes, such as Cx43 and Cx26, are overexpressed in metastatic tumor lesions. Cyclic adenosine monophosphate (cAMP) signaling regulates Cx expression and function via transcriptional control and phosphorylation. cAMP also passes through gap junction channels between adjacent cells, regulating cell cycle progression, particularly in cancer cell populations. Low levels of cAMP are sufficient to activate key effectors. The present review evaluates the mechanisms underlying Cx regulation by cAMP signaling and the role of gap junctions in cancer progression and metastasis. A deeper understanding of these processes might facilitate the development of novel anticancer drugs.
Targeting of Evolutionarily Acquired Cancer Cell Phenotype by Exploiting pHi-Metabolic Vulnerabilities
Authors: Ordway Bryce , Tomaszewski Michal , Byrne Samantha , Abrahams Dominique , Swietach Pawel , Gillies Robert J. , Damaghi Mehdi
Published: December 2020

Evolutionary dynamics can be used to control cancers when a cure is not clinically considered to be achievable. Understanding Darwinian intratumoral interactions of microenvironmental selection forces can be used to steer tumor progression towards a less invasive trajectory. Here, we approach intratumoral heterogeneity and evolution as a dynamic interaction among subpopulations through the application of small, but selective biological forces such as intracellular pH (pHi) and/or extracellular pH (pHe) vulnerabilities. Increased glycolysis is a prominent phenotype of cancer cells under hypoxia or normoxia (Warburg effect). Glycolysis leads to an important aspect of cancer metabolism: reduced pHe and higher pHi. We recently showed that decreasing pHi and targeting pHi sensitive enzymes can reverse the Warburg effect (WE) phenotype and inhibit tumor progression. Herein, we used diclofenac (DIC) repurposed to control MCT activity, and Koningic acid (KA) that is a GAPDH partial inhibitor, and observed that we can control the subpopulation of cancer cells with WE phenotype within a tumor in favor of a less aggressive phenotype without a WE to control progression and metastasis. In a 3D spheroid co-cultures, we showed that our strategy can control the growth of more aggressive MDA-MB-231 cells, while sparing the less aggressive MCF7 cells. In an animal model, we show that our approach can reduce tumor growth and metastasis. We thus propose that evolutionary dynamics can be used to control tumor cells’ clonal or sub-clonal populations in favor of slower growth and less damage to patients. We propose that this can result in cancer control for tumors where cure is not an option.
In Situ TEM Study of Rh Particle Sintering for Three-Way Catalysts in High Temperatures
Authors: Nakayama Hiroki , Nagata Makoto , Abe Hideki , Shimizu Yukihiro
Published: December 2020

One of the main factors in the deterioration of automobile three-way catalysts is the sintering of platinum group metals (PGMs). In this study, we used in situ tunneling electron microscopy (TEM) to examine the sintering of Rh particles as the temperature increases. Two types of environmental conditions were tested, namely, vacuum atmosphere with heating up to 1050 °C, and N2 with/without 1% O2 at 1 atm and up to 1000 °C. Under vacuum, Rh particles appeared to be immersed in ZrO2. In contrast, at 1 atm N2 with or without 1% O2, the sintered Rh particles appeared spherical and not immersed in ZrO2. The latter trend of Rh sintering resembles the actual engine-aged catalyst observed ex situ in this study. In the N2 atmosphere, the sintering of support material (ZrO2 or Y-ZrO2) was first observed by in situ TEM, followed by Rh particle sintering. The Rh particle size was slightly smaller on Y-ZrO2 compared to that on ZrO2. To better understand these experimental results, density functional theory was used to calculate the systems’ junction energies, assuming three layers of Rh(111) 4 × 4 structures joined to the support material (ZrO2 and Y-ZrO2). The calculated energies were consistent with the in situ TEM observations in the N2 atmosphere.
Concatenated Batch and Continuous Flow Procedures for the Upgrading of Glycerol-Derived Aminodiols via N-Acetylation and Acetalization Reactions
Authors: Rigo Davide , Carmo Dos Santos Nadia Alessandra , Perosa Alvise , Selva Maurizio
Published: December 2020

An unprecedented two-step sequence was designed by combining batch and continuous flow (CF) protocols for the upgrading of two aminodiol regioisomers derived from glycerol, i.e., 3-amino-1,2-propanediol and 2-amino-1,3-propanediol (serinol). Under batch conditions, at 80–90 °C, both substrates were quantitatively converted into the corresponding amides through a catalyst-free N-acetylation reaction mediated by an innocuous enol ester as isopropenyl acetate (iPAc). Thereafter, at 30–100 °C and 1–10 atm, the amide derivatives underwent a selective CF-acetalisation in the presence of acetone and a solid acid catalyst, to afford the double-functionalized (amide-acetal) products.
Ordered Mesoporous Carbon as a Support for Palladium-Based Hydrodechlorination Catalysts
Authors: Sakina Farzeen , Fernandez-Ruiz Carlos , Bedia Jorge , Gomez-Sainero Luisa , Baker Richard
Published: December 2020

Ordered mesoporous carbon (OMC) was employed as a support for palladium nanoparticles in catalysts for the gas phase hydrodechlorination (HDC) of trichloromethane (TCM). 1 wt% palladium was incorporated using three methods: incipient wetness (IW); a dilute solution (DS) method; and a solid-liquid (SL) method. The effect of the preparation method on catalyst structure and activity was investigated. Catalyst composition and nanostructure were studied using gas physisorption, high specification transmission electron microscopy and X-ray photoelectron spectroscopy. Catalytic conversion and product selectivities were determined in steady-state activity tests at temperatures between 70 and 300 °C. Two of the catalysts (IW and DS) showed excellent dispersion of fine Pd nanoparticles of average diameter ~2 nm. These materials showed excellent activity for HDC of TCM which compares favourably with the performance reported for Pd on amorphous carbon catalysts. In addition, they showed relatively high selectivities to the more valuable higher hydrocarbons. However, the SL method gave rise to catalysts with larger particles (~3 nm) and a less uniform palladium distribution. This resulted in lower conversion and lower selectivities to higher hydrocarbons and in more severe catalyst deactivation at the highest reaction temperatures.
New Molecular Players in the Development of Callosal Projections
Authors: Ku Ray , Torii Masaaki
Published: December 2020

Cortical development in humans is a long and ongoing process that continuously modifies the neural circuitry into adolescence. This is well represented by the dynamic maturation of the corpus callosum, the largest white matter tract in the brain. Callosal projection neurons whose long-range axons form the main component of the corpus callosum are evolved relatively recently with a substantial, disproportionate increase in numbers in humans. Though the anatomy of the corpus callosum and cellular processes in its development have been intensively studied by experts in a variety of fields over several decades, the whole picture of its development, in particular, the molecular controls over the development of callosal projections, still has many missing pieces. This review highlights the most recent progress on the understanding of corpus callosum formation with a special emphasis on the novel molecular players in the development of axonal projections in the corpus callosum.
Cyclic Stretch of Either PNS or CNS Located Nerves Can Stimulate Neurite Outgrowth
Authors: Kampanis Vasileios , Tolou-Dabbaghian Bahardokht , Zhou Luming , Roth Wolfgang , Puttagunta Radhika
Published: December 2020

The central nervous system (CNS) does not recover from traumatic axonal injury, but the peripheral nervous system (PNS) does. We hypothesize that this fundamental difference in regenerative capacity may be based upon the absence of stimulatory mechanical forces in the CNS due to the protective rigidity of the vertebral column and skull. We developed a bioreactor to apply low-strain cyclic axonal stretch to adult rat dorsal root ganglia (DRG) connected to either the peripheral or central nerves in an explant model for inducing axonal growth. In response, larger diameter DRG neurons, mechanoreceptors and proprioceptors showed enhanced neurite outgrowth as well as increased Activating Transcription Factor 3 (ATF3).
Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Show Comparable Functionality to Their Autologous Origin
Authors: Jakob Mark , Hambrecht Mario , Spiegel Jennifer L. , Kitz Julia , Canis Martin , Dressel Ralf , Streckfuss-Bömeke Katrin
Published: December 2020

A multimodal therapeutic approach involving radiotherapy is required when treating head and neck squamous cell carcinoma. However, radiotherapy is restricted due to its high risk for damages to the surrounding healthy tissue of the treated area. Tissue regeneration and wound healing is promoted by the survival and regenerative capacities of tissue-resident or invading stem cells. Mesenchymal stem cells (MSCs) exhibit a promising therapeutic potential in the field of cell-based tissue engineering and regenerative medicine due to their immunomodulatory properties and differentiation capacity. However, the generation of MSCs for therapeutic applications is still a major challenge. We aimed to produce highly homogeneous induced pluripotent stem cell-derived mesenchymal stem cells (iP-MSCs) in an autologous manner from initially isolated human mucosa mesenchymal stem cells (mMSCs) of the upper respiratory tract. Therefore, mMSCs were reprogrammed into induced pluripotent stem cells (iPSCs) by non-integrative chromosomal technologies and differentiated into corresponding iP-MSCs. We demonstrated that mMSCs and iP-MSCs show similar cell characteristics in terms of morphology, clonogenic potential, differentiation, and surface phenotype. Moreover, iP-MSCs demonstrated related immunosuppressive capacity as mMSCs including the secretion of cytokines, and T cell inhibition. Therefore, generating iP-MSCs in an autologous manner may be a novel personalized treatment option in regenerative medicine.
Vegetarian Diets and Eating Disorders in Adolescents and Young Adults: A Systematic Review
Authors: Sergentanis Theodoros N. , Chelmi Maria-Eleni , Liampas Andreas , Yfanti Chrysanthi-Maria , Panagouli Eleni , Vlachopapadopoulou Elpis , Michalacos Stefanos , Bacopoulou Flora , Psaltopoulou Theodora , Tsitsika Artemis
Published: December 2020

Background: Eating disorders are more common among adolescents and young adults. An increase in the rates of these disorders has been reported during the last years. Meanwhile, vegetarianism is becoming more popular in these age groups. The purpose of the present paper is to evaluate the association between eating disorders and vegetarian diets in adolescents and young adults. Methods: Systematic review of related articles published in PubMed, PsycInfo and Google Scholar up to 30 May 2019. Results: A total of 20 studies (14,391 subjects) were deemed eligible for this systematic review. The majority of the studies reported significant correlations between vegetarianism and eating disorders. However, due to the cross-sectional design, a causal link between eating disorders and vegetarian status cannot be established. Conclusions: Vegetarianism seems to be associated with eating disorders. Longitudinal studies are needed to establish temporal patterns between vegetarianism and the emergence of disordered eating.
Optics of Inhomogeneous Thin Films with Defects: Application to Optical Characterization
Authors: Ohlídal Ivan , Vohánka Jiří , Čermák Martin
Published: December 2020

This review paper is devoted to optics of inhomogeneous thin films exhibiting defects consisting in transition layers, overlayers, thickness nonuniformity, boundary roughness and uniaxial anisotropy. The theoretical approaches enabling the inclusion of these defects into formulae expressing the optical quantities of these inhomogeneous thin films are summarized. These approaches are based on the recursive and matrix formalisms for the transition layers and overlayers, averaging of the elements of the Mueller matrix using local thickness distribution or polynomial formulation for the thickness nonuniformity, scalar diffraction theory and Rayleigh-Rice theory or their combination for boundary roughness and Yeh matrix formalism for uniaxial anisotropy. The theoretical results are illustrated using selected examples of the optical characterization of the inhomogeneous polymer-like thin films exhibiting the combination of the transition layers and thickness nonuniformity and inhomogeneous thin films of nonstoichiometric silicon nitride with the combination of boundary roughness and uniaxial anisotropy. This characterization is realized by variable angle spectroscopic ellipsometry and spectroscopic reflectometry. It is shown that using these optical techniques, the complete optical characterization of the mentioned thin films can be performed. Thus, it is presented that the values of all the parameters characterizing these films can be determined.
Study on the Friction Performance of Cerium Oxide on Supersonic Flame-Sprayed WC-10Co-4Cr Coating
Authors: Ma Wenxiao , Ge Yun , Zhang Lixin , Chen Fei , Zheng Yijiang , Qi Zhuhui
Published: December 2020

In order to improve the surface wear resistance of the key parts of agricultural machinery, this article uses 65Mn steel, which is commonly used in agricultural machinery, as the matrix and tungsten carbide-based coating as the basis. In total, two coating materials are selected as WC-10Co-4Cr with and without CeO2 added. The coating was prepared by the supersonic flame spraying process (HVOF), and the tribological characteristics and coating of the three samples of 65Mn, WC-10Co-4Cr, and WC-10Co-4Cr+CeO2 coatings were investigated by the comprehensive material surface performance tester. Layer porosity, microhardness, and X-ray powder diffraction (XRD) phase analysis reveal the modification mechanism of WC-10Co-4Cr coating by rare earth CeO2. The experimental comparison results show that WC-10Co-4Cr is prepared on the 65Mn steel substrate, and the WC-10Co-4Cr+CeO2 coating significantly improves the surface hardness, the coating structure is uniform and dense, and the pores are less. The coating hardness value is relatively high, reaching 1200–1500 HV(N/mm2), and the porosity is less than 1%. When the rare earth cerium oxide is added to WC-10Co-4Cr, the porosity of the coating decreases and the hardness increases. It is proved that rare earth has the modification effect of refining the coating structure. Therefore, adding CeO2 to the WC-10Co-4Cr coating and using the supersonic flame spraying process to prepare the coating can obtain more excellent wear resistance.
Hollow IF-MoS2/r-GO Nanocomposite Filled Polyimide Coating with Improved Mechanical, Thermal and Tribological Properties
Authors: Wu Jian , Yin Xiang , Mu Liwen , Feng Xin , Lu Xiaohua , Shi Yijun
Published: December 2020

Polyimide (PI) is one of the most excellent polymers for coating. However, the high friction coefficient and the high wear rate of pure PI limit its further applications. In this work, the hollow inorganic fullerene-like MoS2/reduced graphene oxide (HIF-MoS2/r-GO) nanocomposite filled PI coating is prepared by in situ polymerization. Reinforcement in mechanical strength and thermal stability is realized on the PI composite coating with incorporation of HIF-MoS2/r-GO, which performs better than carbon nanofiber (CNF). Reduced elastic modulus and hardness of HIF-MoS2/r-GO/PI coating is increased by 8.3% and 4.8%, respectively. The addition of HIF-MoS2/r-GO also results in 24% higher residual mass at 800 °C than CNF. Tribological study indicates that, HIF-MoS2/r-GO/PI achieves a wear rate reduction of 79% compared with pure PI under dry sliding condition, which is much more effective than other nanofillers including CNF, r-GO nanosheets and MoS2 nanoparticles. Under ionic liquid-lubricated condition, the presence of HIF-MoS2/r-GO in PI results in a 30% reduction in wear rate and 10% reduction in friction coefficient as compared to pure PI. It is thought that the HIF-MoS2/r-GO in PI can be slowly released to the frictional interface and form a protective film during sliding, in this way the aggregation problem is successfully solved.
Smart Contract Data Feed Framework for Privacy-Preserving Oracle System on Blockchain
Authors: Park Junhoo , Kim Hyekjin , Kim Geunyoung , Ryou Jaecheol
Published: December 2020

As blockchain-based applications and research such as cryptocurrency increase, an oracle problem to bring external data in the blockchain is emerging. Among the methods to solve the oracle problem, a method of configuring oracle based on TLS, an existing internet infrastructure, has been proposed. However, these methods currently have the disadvantage of not supporting privacy protection for external data, and there are limitations in configuring the process of a smart contract based on external data verification for automation. To solve this problem, we propose a framework consisting of middleware of external source server, data prover, and verification contract. The framework converts the data signed in the web server into a proof that the owner can prove with zk-SNARKs and provides a smart contract that can verify this. Through these procedures, data owners not only protect their privacy by proving themselves, but they can also automate on-chain processing through smart contract verification. For the proposed framework, we create a proof using libsnark for server data and show the performance and cost to verify with Solidity the smart contract language of the Ethereum platform.
Moringa oleifera Seed Oil Formulation Physical Stability and Chemical Constituents for Enhancing Skin Hydration and Antioxidant Activity
Authors: Athikomkulchai Sirivan , Tunit Prakairat , Tadtong Sarin , Jantrawut Pensak , Sommano Sarana Rose , Chittasupho Chuda
Published: December 2020

Moringa oleifera seed oil has been recognized for its benefits in relation to the skin. The objective of this study was to evaluate the chemical composition and antioxidant activity of moringa seed oil, to formulate a moringa seed oil cream, and to determine the efficacy of moringa seed oil cream in vivo. The chemical components of moringa seed oil were analyzed by high-performance liquid chromatography and gas chromatography. The antioxidant activity of the oil was determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay. An oil-in-water cream containing moringa seed oil was developed and characterized for antioxidant activity. The moringa seed oil cream was further subjected to the accelerated stability test of heating–cooling cycles for six cycles and stored isothermally at 4, 30, and 45 °C for 28 days. The efficacy of moringa seed oil cream was investigated in 32 participants by measuring their skin hydration, erythema, melanin values, and visco-elasticity. The results showed that moringa seed oil contained α-tocopherol, plant sterols, and fatty acids. The oil had antioxidant activity with a 50% of initial concentration (IC50) value of 121.9 mg/mL. The stability study indicated that the pH, viscosity, and rheological behavior of the cream containing moringa seed oil were not significantly changed after storage at 4, 30, and 45 °C for 28 days and six heating–cooling cycles. The moringa seed oil cream exhibited in vitro antioxidant activity and increased the in vivo skin hydration level compared with the cream base. There was no report of skin irritation from moringa seed oil cream application, suggesting that the moringa seed oil cream developed in this study was appropriate for pharmaceutical and cosmetic uses. A M. oleifera seed oil cream was successfully developed. The moringa seed oil cream possessed antioxidant activity, enhanced the skin hydration level, and reduced skin erythema, but did not affect the melanin content and skin visco-elasticity. The moringa seed oil cream did not induce skin irritation and, thus, was safe to use.
Synthesis of Metal Organic Frameworks by Ball-Milling
Authors: Tao Cheng-An , Wang Jian-Fang
Published: December 2020

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.
Is There an Association between Temporomandibular Disorders and Articular Eminence Inclination? A Systematic Review
Authors: Fan Xiao-Chuan , Singh Diwakar , Ma Lin-Sha , Piehslinger Eva , Huang Xiao-Feng , Rausch-Fan Xiaohui
Published: December 2020

(1) Background: In order to determine the correlation between the inclination of articular eminence (AEI) and the development of temporomandibular disorders (TMDs), a systematic review was performed. (2) Methods: A systematic literature research was conducted between 1946 and January 2020, based on the following electronic databases: PubMed, Cochrane Library, Embase, Medline, Scope, SciELO, and Lilacs. Observational studies, analytical case-control studies, and cohort studies written in English were identified. The articles were selected and analyzed by two authors independently. The PICO format was used to analyze the studies and the Newcastle-Ottawa Scale (NOS) was used to verify the quality of the evidence. (3) Results: Sixteen articles were included in this review, ten case-control studies and six cohort studies. Eight articles (50%) established a positive relation between AEI and TMDs and eight (50%) did not. The scientific quality was medium-low, mainly influenced by the exposure to the risk of bias and the lack of clinical methods with adequate consistency and sensitivity on the diagnosis of TMDs. (4) Conclusions: It is controversial to establish a causal relationship between the TMDs and the AEI in the field of stomatology, due to limited and inconclusive evidence. However, it is suggested that the AEI defined by some specific methods may be associated with some special pathological stages of TMDs. High-quality prospective studies are required to draw any definitive conclusions.
Nerve Ultrasound in Traumatic and Iatrogenic Peripheral Nerve Injury
Authors: Wijntjes Juerd , Borchert Alexandra , van Alfen Nens
Published: December 2020

Peripheral nerve injury is a potentially debilitating disorder that occurs in an estimated 2–3% of all patients with major trauma, in a similar percentage of medical procedures. The workup of these injuries has traditionally been clinical, combined with electrodiagnostic testing. However, this has limitations, especially in the acute phase of the trauma or lack of any recovery, when it is very important to determine nerve continuity and perform surgical exploration and repair in the case of the complete transection or intraneural fibrosis. Ultrasound can help in those situations. It is a versatile imaging technique with a high sensitivity of 93% for detecting focal nerve lesions. Ultrasound can assess the structural integrity of the nerve, neuroma formation and other surrounding abnormalities of bone or foreign bodies impeding the nerve. In addition, this can help to prevent iatrogenic nerve injury by marking the nerve before the procedure. This narrative review gives an overview of why and how nerve ultrasound can play a role in the detection, management and prevention of peripheral nerve injury.
Genetic Abnormalities in Pancreatitis: An Update on Diagnosis, Clinical Features, and Treatment
Authors: Suzuki Mitsuyoshi , Minowa Kei , Nakano Satoshi , Isayama Hiroyuki , Shimizu Toshiaki
Published: December 2020

Several pancreatitis susceptibility genes have been identified to date. A relationship between a mutation in the cationic trypsinogen (protease serine 1, PRSS1) gene and hereditary pancreatitis (HP) was first identified in 1996. Currently, HP has been defined as either two or more individuals within a family exhibiting pancreatitis for two or more generations, or pancreatitis linked to mutation of the PRSS1 gene. In 2000, a mutation in the serine protease inhibitor gene (Kazal type 1: SPINK1) was reported to be related to sporadic pancreatitis of unknown etiology. This paper reviews and summarizes the current published data on the pancreatitis susceptibility genes, mainly PRSS1 and SPINK1 genes, and introduces a diagnostic and therapeutic approach for dealing with patients with these gene mutations. Patients with these genetic predispositions, both children and adults, have often been initially diagnosed with idiopathic acute pancreatitis, in approximately 20–50% of pediatric cases and 28–80% of adult cases. In such patients, where the etiology is unknown, genetic testing, which requires pre-test and post-test genetic counselling, may prove helpful. Patients with chronic pancreatitis (CP) due to SPINK1 gene mutation and HP patients have a potentially high risk of pancreatic exocrine insufficiency, diabetes mellitus, and, of particular importance, pancreatic cancer. Thus, these patients require careful long-term follow-up and management. Specifically, symptomatic CP patients often need endoscopic therapy or surgery, often following a step-up approach beginning with endoscopic therapy and progressing to surgery if necessary, which is similar to the therapeutic approach for patients with CP due to other etiologies. It is important that clinicians are aware of the characteristics of patients with pancreatitis susceptibility genetic abnormalities.
Development and Evaluation of an Electrochemical Biosensor for Detection of Dengue-Specific IgM Antibody in Serum Samples
Authors: Parkash Om , Abdullah Muhammad Amiruddin , Yean Chan Yean , Sekaran Shamala Devi , Shueb Rafidah Hanim
Published: December 2020

Dengue is an arbovirus disease transmitted mainly by Aedes mosquitoes. As dengue shares similar clinical symptoms with other infectious diseases, prompt and accurate diagnosis is pivotal to clinicians’ decisions on appropriate management. Conventional diagnostic tests to detect the dengue-specific IgM antibody are limited in their performance and ease of use. To address these issues, we developed and evaluated a biosensor based on screen-printed carbon electrodes (SPCEs) for the detection of dengue-specific immunoglobulin M (IgM) antibodies. Various optimisations were performed in order to increase the sensitivity and specificity of the biosensor. For optimal and proper orientation of the paratope sites of goat anti-human IgM capture antibodies (GAHICA), various antibody techniques, including passive, covalent, protein A, protein G and streptavidin/biotin systems, were tested on the SPCEs. The assay reagents for the biosensor were also optimised prior to its evaluation. Analytical sensitivity evaluation was carried out using pooled sera, while analytical specificity evaluation was conducted on a panel of six non-dengue serum samples. Subsequently, diagnostic sensitivity and specificity evaluation were performed using 144 reference samples. Electrochemical current signals generated from H2O2 catalysed by HRP-labelled anti-dengue detection antibodies were measured using the chronoamperometric technique. With a limit of detection (LOD) of 106 serum dilution, the analytical sensitivity of the developed biosensor was 10 times higher than commercial ELISA. The analytical specificity of this dengue IgM biosensor was 100%. Similarly, the biosensor’s diagnostic performance was 100% for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). These findings suggest that the developed biosensor has a great potential to be used to diagnose dengue after seroconversion.
Diagnostic Value of CEUS Prompting Liver Biopsy: Histopathological Correlation of Hepatic Lesions with Ambiguous Imaging Characteristics
Authors: Geyer Thomas , Clevert Dirk-André , Schwarz Sonja , Reidler Paul , Gassenmaier Sebastian , Knösel Thomas , Rübenthaler Johannes , Schwarze Vincent , Armbruster Marco
Published: December 2020

Background: Contrast-enhanced ultrasound (CEUS) allows for dynamic analysis of vascularization patterns of unclear hepatic lesions. Our study aimed to evaluate the diagnostic performance of CEUS for further characterizing suspicious liver lesions by comparing findings from CEUS examinations with corresponding histopathology. Methods: Between 2005 and 2016, 160 patients with unclear liver lesions underwent CEUS followed by liver biopsy. All examinations were performed by an experienced consultant radiologist (EFSUMB Level 3) and included native B-mode ultrasound, Color Doppler, and CEUS. A second-generation blood pool contrast agent was applied for CEUS. Results: CEUS was successfully performed in all patients without occurrence of any adverse side effects. CEUS showed a sensitivity of 94.5%, a specificity of 70.6%, a true positive rate of 87.3%, and a true negative rate of 85.7% compared to histopathological results as the reference standard. Conclusions: CEUS represents a safe imaging modality with a high diagnostic accuracy in assessing both—benign and malignant—liver lesions compared to corresponding histopathological results.
Bayesian Update with Importance Sampling: Required Sample Size
Authors: Sanz-Alonso Daniel , Wang Zijian
Published: December 2020

Importance sampling is used to approximate Bayes’ rule in many computational approaches to Bayesian inverse problems, data assimilation and machine learning. This paper reviews and further investigates the required sample size for importance sampling in terms of the χ2-divergence between target and proposal. We illustrate through examples the roles that dimension, noise-level and other model parameters play in approximating the Bayesian update with importance sampling. Our examples also facilitate a new direct comparison of standard and optimal proposals for particle filtering.
Deep Neural Networks for Behavioral Credit Rating
Authors: Merćep Andro , Mrčela Lovre , Birov Matija , Kostanjčar Zvonko
Published: December 2020

Logistic regression is the industry standard in credit risk modeling. Regulatory requirements for model explainability have halted the implementation of more advanced, non-linear machine learning algorithms, even though more accurate predictions would benefit consumers and banks alike. Deep neural networks are certainly some of the most prominent non-linear algorithms. In this paper, we propose a deep neural network model for behavioral credit rating. Behavioral models are used to assess the future performance of a bank’s existing portfolio in order to meet the capital requirements introduced by the Basel regulatory framework, which are designed to increase the banks’ ability to absorb large financial shocks. The proposed deep neural network was trained on two different datasets: the first one contains information on loans between 2009 and 2013 (during the financial crisis) and the second one from 2014 to 2018 (after the financial crisis); combined, they include more than 1.5 million examples. The proposed network outperformed multiple benchmarks and was evenly matched with the XGBoost model. Long-term credit rating performance is also presented, as well as a detailed analysis of the reprogrammed facilities’ impact on model performance.
Entropy-Based Approach in Selection Exact String-Matching Algorithms
Authors: Markić Ivan , Štula Maja , Zorić Marija , Stipaničev Darko
Published: December 2020

The string-matching paradigm is applied in every computer science and science branch in general. The existence of a plethora of string-matching algorithms makes it hard to choose the best one for any particular case. Expressing, measuring, and testing algorithm efficiency is a challenging task with many potential pitfalls. Algorithm efficiency can be measured based on the usage of different resources. In software engineering, algorithmic productivity is a property of an algorithm execution identified with the computational resources the algorithm consumes. Resource usage in algorithm execution could be determined, and for maximum efficiency, the goal is to minimize resource usage. Guided by the fact that standard measures of algorithm efficiency, such as execution time, directly depend on the number of executed actions. Without touching the problematics of computer power consumption or memory, which also depends on the algorithm type and the techniques used in algorithm development, we have developed a methodology which enables the researchers to choose an efficient algorithm for a specific domain. String searching algorithms efficiency is usually observed independently from the domain texts being searched. This research paper aims to present the idea that algorithm efficiency depends on the properties of searched string and properties of the texts being searched, accompanied by the theoretical analysis of the proposed approach. In the proposed methodology, algorithm efficiency is expressed through character comparison count metrics. The character comparison count metrics is a formal quantitative measure independent of algorithm implementation subtleties and computer platform differences. The model is developed for a particular problem domain by using appropriate domain data (patterns and texts) and provides for a specific domain the ranking of algorithms according to the patterns’ entropy. The proposed approach is limited to on-line exact string-matching problems based on information entropy for a search pattern. Meticulous empirical testing depicts the methodology implementation and purports soundness of the methodology.
The Continuous Intention to Use E-Learning, from Two Different Perspectives
Authors: Saeed Al-Maroof Rana , Alhumaid Khadija , Salloum Said
Published: December 2020

During the recent vast growth of digitalization, e-learning methods have become the most influential phenomenon at higher educational institutions. E-learning adoption has proved able to shift educational circumstances from the traditional face-to-face teaching environment to a flexible and sharable type of education. An online survey was conducted, consisting of 30 teachers and 342 students in one of the universities in the United Arab Emirates. The results show that teachers’ and students’ perceived technology self-efficacy (TSE), ease of use (PEOU), and usefulness (PU) are the main factors directly affecting the continuous intention to use technology. Instructors’ technological pedagogical content knowledge (TPACK) and perceived organizational support (POS) positively affect the intention to use the technology, whereas students’ controlled motivation (CTRLM) has a greater influence on their intention to use the technology, due to the type of intrinsic and extrinsic motivation that they have and which they can develop throughout the process of learning. The findings support the given hypotheses. In addition, they provide empirical evidence of a relationship between perceived organizational support and perceived pedagogical content knowledge. In fact, they are considered the key factors that support the use of technology continuously.
Systematical Study of the Basic Properties of Surface Acoustic Wave Devices Based on ZnO and GaN Multilayers
Authors: Shen Junyao , Fu Sulei , Su Rongxuan , Xu Huiping , Zeng Fei , Song Cheng , Pan Feng
Published: December 2020

Recently, surface acoustic wave (SAW) devices based on layered structures are a popular area of research. Multilayered structures, including ZnO and GaN, have shown great performance and can be applied in diverse fields. Meanwhile, thin films, such as AlGaN and n-ZnO, can be added to these structures to form a 2-D electron gas (2DEG) which makes the devices tunable. This work systematically studies the basic properties of SAW devices based on ZnO and GaN multilayers via COMSOL Multiphysics. The sorts of structures with different crystal orientations are simulated, and various acoustic modes are considered. Results show that a range of phase velocity from about 2700 m/s to 6500 m/s can be achieved, and devices based on ZnO and GaN multilayers can meet the requirements of the electromechanical coupling coefficient from about 0 to 7%. Every structure’s unique properties are valuable for diverse applications. For example, c-ZnO/c-GaN/c-sapphire structure can be used for high-frequency and large-bandwidth SAW devices, while SAW devices based on a-ZnO/a-GaN/r-sapphire and 2DEG are suitable for programmable SAW sensors. This work has great reference value for future research into SAW devices.
A Hybrid Approach Based on SOCP and the Discrete Version of the SCA for Optimal Placement and Sizing DGs in AC Distribution Networks
Authors: Montoya Oscar Danilo , Molina-Cabrera Alexander , Chamorro Harold R. , Alvarado-Barrios Lazaro , Rivas-Trujillo Edwin
Published: December 2020

This paper deals with the problem of the optimal placement and sizing of distributed generators (DGs) in alternating current (AC) distribution networks by proposing a hybrid master–slave optimization procedure. In the master stage, the discrete version of the sine–cosine algorithm (SCA) determines the optimal location of the DGs, i.e., the nodes where these must be located, by using an integer codification. In the slave stage, the problem of the optimal sizing of the DGs is solved through the implementation of the second-order cone programming (SOCP) equivalent model to obtain solutions for the resulting optimal power flow problem. As the main advantage, the proposed approach allows converting the original mixed-integer nonlinear programming formulation into a mixed-integer SOCP equivalent. That is, each combination of nodes provided by the master level SCA algorithm to locate distributed generators brings an optimal solution in terms of its sizing; since SOCP is a convex optimization model that ensures the global optimum finding. Numerical validations of the proposed hybrid SCA-SOCP to optimal placement and sizing of DGs in AC distribution networks show its capacity to find global optimal solutions. Some classical distribution networks (33 and 69 nodes) were tested, and some comparisons were made using reported results from literature. In addition, simulation cases with unity and variable power factor are made, including the possibility of locating photovoltaic sources considering daily load and generation curves. All the simulations were carried out in the MATLAB software using the CVX optimization tool.
Digital Implementation Method for Synchronous PWM Control of GaN Transistor at Zero-Crossing of Totem-Pole PFC in Energy Storage Applications
Authors: Kwak Bongwoo , Kim Jonghoon
Published: December 2020

A digital control scheme for GaN transistor-based totem pole power factor correction (PFC) is proposed in this paper. At the zero crossing, the totem pole PFC has a discontinuous conduction mode (DCM) current section because of its driving method and circuit structure. In the DCM current section, when a typical synchronous switching technique is applied, the inductor current is reduced to less than zero, thereby reducing efficiency. Moreover, because of the nature of the circuit, power may be transferred in reverse. To prevent this, a new synchronous switch technique using the cycle by cycle (CBC) trip function of the digital signal processor (DSP) is proposed. This proposed technique turns off the synchronization switch according to the set DCM level. Consequently, even at a low DCM level, the inductor current is clamped to zero, enabling stable synchronous switching.
A Novel Structure and Operation Scheme of Vertical Channel NAND Flash with Ferroelectric Memory for Multi String Operations
Authors: Choi Seonjun , Choi Changhwan , Jeong Jae Kyeong , Kang Myounggon , Song Yun-heub
Published: December 2020

In this study, the operation method of the proposed ferroelectric memory structure as a method to overcome the limitations of the existing Charge Trap Flash (CTF) memory Vertical NAND (V-NAND) structure was presented and verified through device simulation. The proposed structure and operation method applied the BiCS (Bit Cost Scalable) structure GIDL (Gate Induce Drain Leakage) deletion method to confirm that selective program operation is possible in the ferroelectric memory V-NAND (Vertical Channel NAND) structure. In particular, we confirmed that the proposed method can easily suppress the program operation by adjusting the hole density of the channel even in the “Y-mode” operation. The channel hole density adjustment that makes this possible can be easily controlled by the voltage difference between the bit line (BL) and drain select line (DSL) contacts. The proposed structure was verified through a device simulation, and as a result of the verification, it was confirmed that the channel hole can be selectively charged in the program operation. Through this, when the cell to be programmed shows the program operation of 2.3 V, the other cells do not. It was confirmed that it could be suppressed to 0.4 V.
Traffic Type Recognition Method for Unknown Protocol—Applying Fuzzy Inference
Authors: Kim Sang-Won , Kim Kee-Cheon
Published: December 2020

In this paper, we propose a system that can recognize traffic types without prior knowledge of static features such as protocol header information by combining protocol analysis based on an ecological sequence alignment algorithm in a bioinformatics and fuzzy inference system. The algorithm proposed in this paper obtained up to a 91% level of performance at a similar level to several existing algorithms in experiments using datasets containing various types of traffic. In addition, it showed an excellent accuracy of 82.5% or more even under severe conditions that lowered the amount of data to a level of at least 40% or only included data in the middle of the traffic. This shows that the problem of dependence on initial data that frequently occurs in existing machine learning and deep learning-based traffic classification algorithms does not appear in the proposed algorithm. Furthermore, based on the ability to directly extract traffic characteristics without being dependent on static field values, it has secured the ability to respond with a small number of data by taking advantage of the flexibility of the membership function of the fuzzy inference engine. Through this, the applicability to low-power and low-performance environments such as IoT networks was confirmed. In this paper, we describe in detail the theoretical background for constructing such an algorithm and relevant experiments and considerations for actual verification.
NO Formation and Autoignition Dynamics during Combustion of H2O-Diluted NH3/H2O2 Mixtures with Air
Authors: Khalil Ahmed T. , Manias Dimitris M. , Kyritsis Dimitrios C. , Goussis Dimitris A.
Published: December 2020

NO formation, which is one of the main disadvantages of ammonia combustion, was studied during the isochoric, adiabatic autoignition of ammonia/air mixtures using the algorithm of Computational Singular Perturbation (CSP). The chemical reactions supporting the action of the mode relating the most to NO were shown to be essentially the ones of the extended Zeldovich mechanism, thus indicating that NO formation is mainly thermal and not due to fuel-bound nitrogen. Because of this, addition of water vapor reduced NO formation, because of its action as a thermal buffer, but increased ignition delay, thus exacerbating the second important caveat of ammonia combustion, which is unrealistically long ignition delay. However, it was also shown that further addition of just 2% molar of H2O2 does not only reduce the ignition delay by a factor of 30, but also reverses the way water vapor affects ignition delay. Specifically, in the ternary mixture NH3/H2O/H2O2, addition of water vapor does not prolong but rather shortens ignition delay because it increases OH radicals. At the same time, the presence of H2O2 does not affect the influence of H2O in suppressing NO generation. In this manner, we were able to show that NH3/H2O/H2O2 mixtures offer a way to use ammonia as carbon-less fuel with acceptable NOx emissions and realistic ignition delay.
A Novel Integrated Profit Maximization Model for Retailers under Varied Penetration Levels of Photovoltaic Systems
Authors: Panapakidis Ioannis P. , Koltsaklis Nikolaos , Christoforidis Georgios C.
Published: December 2020

In contemporary energy markets, the Retailer acts as the intermediate between the generation and demand sectors. The scope of the Retailer is to maximize its profits by selecting the appropriate procurement mechanism and selling price to the consumers. The wholesale market operation influences the profits since the mix of generation plants determines the system marginal price (SMP). In the related literature, the SMP is treated as a stochastic variable, and the wholesale market conditions are not taken into account. The present paper presents a novel methodology that aims at connecting the wholesale and retail market operations from a Retailer’s perspective. A wholesale market clearing problem is formulated and solved. The scope is to examine how different photovoltaics (PV) penetration levels in the generation side influences the profits of the Retailer and the selling prices to the consumers. The resulting SMPs are used as inputs in a retailer profit maximization problem. This approach allows the Retailer to minimize economic risks and maximize profits. The results indicate that different PV implementation levels on the generation side highly influences the profits and the selling prices.