bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Biopsies in Head and Neck Cancer: Current State and Future Challenges
Authors: Kong Lingyi , Birkeland Andrew C.
Published: April 2021

Head and neck cancers are the seventh most frequent malignancy worldwide, consisting of a heterogeneous group of cancers that develop in the oral cavity, pharynx, and larynx, with head and neck squamous cell carcinoma (HNSCC) being the most common pathology. Due to limitations with screening and physical examination, HNSCC often presents in advanced disease states and is thus associated with poor survival. In this setting, liquid biopsies, or obtaining patient bodily fluid samples for cancer diagnosis and prognosis, may play a dramatic role in optimizing care for HNSCC patients. In recent years, there have been dramatic advancements in investigations focused on optimizing and implementing liquid biopsies in general, and specifically for HNSCC patients. Moving forward, there remain significant challenges in liquid biopsy technological development, as well as opportunities for the development of HNSCC liquid biopsy clinical trials and treatment paradigms. In this review, we discuss the current state of liquid biopsy technologies via circulating tumor cells, circulating tumor DNA and exosomes, approaches in head and neck cancer, challenges to optimization and application of liquid biopsies for clinical study, and future prospects for this field of research as it applies to head and neck cancer.
Adjuvant Systemic Therapy after Chemoradiation and Brachytherapy for Locally Advanced Cervical Cancer: A Systematic Review and Meta-Analysis
Authors: Horeweg Nanda , Mittal Prachi , Gradowska Patrycja L. , Boere Ingrid , Chopra Supriya , Nout Remi A.
Published: April 2021

Background: Standard of care for locally advanced cervical cancer is chemoradiation and brachytherapy. The addition of adjuvant systemic treatment may improve overall survival. A systematic review and meta-analysis was conducted to summarize evidence on survival outcomes, treatment completion and toxicity. Methods: PubMed, EMBASE and Web of Science were systematically searched for relevant prospective and retrospective studies. Two authors independently selected studies, extracted data and assessed study quality. Pooled hazard ratios for survival endpoints were estimated using random effect models. Weighted averages of treatment completion and toxicity rates were calculated and compared by the Fisher exact test. Results: The search returned 612 articles; 35 articles reporting on 29 different studies on adjuvant chemotherapy or immunotherapy were selected for systematic review. Twelve studies on an adjuvant platinum–pyrimidine antagonist or platinum–taxane were included for meta-analysis. The pooled hazard ratios for overall survival were 0.76 (99%CI: 0.43–1.34, p = 0.22) and 0.47 (99%CI: 0.12–1.86, p = 0.16) for the addition of, respectively, a platinum–pyrimidine antagonist or platinum–taxane to chemoradiation and brachytherapy. Completion rates were 82% (95%CI: 76–87%) for platinum–pyrimidine antagonist and 74% (95%CI: 63–85%) for platinum–taxane. Severe acute hematological and gastro-intestinal toxicities were significantly increased by adding adjuvant chemotherapy to chemoradiation and brachytherapy. Conclusions: The addition of adjuvant platinum–pyrimidine antagonist or platinum–taxane after chemoradiation and brachytherapy does not significantly improve overall survival, while acute toxicity is significantly increased. These adjuvant treatment strategies can therefore not be recommended for unselected patients with locally advanced cervical cancer.
Cytoskeletal Dynamics in Epithelial-Mesenchymal Transition: Insights into Therapeutic Targets for Cancer Metastasis
Authors: Datta Arpita , Deng Shuo , Gopal Vennila , Yap Kenneth Chun-Hong , Halim Clarissa Esmeralda , Lye Mun Leng , Ong Mei Shan , Tan Tuan Zea , Sethi Gautam , Hooi Shing Chuan , Kumar Alan Prem , Yap Celestial T.
Published: April 2021

In cancer cells, a vital cellular process during metastasis is the transformation of epithelial cells towards motile mesenchymal cells called the epithelial to mesenchymal transition (EMT). The cytoskeleton is an active network of three intracellular filaments: actin cytoskeleton, microtubules, and intermediate filaments. These filaments play a central role in the structural design and cell behavior and are necessary for EMT. During EMT, epithelial cells undergo a cellular transformation as manifested by cell elongation, migration, and invasion, coordinated by actin cytoskeleton reorganization. The actin cytoskeleton is an extremely dynamic structure, controlled by a balance of assembly and disassembly of actin filaments. Actin-binding proteins regulate the process of actin polymerization and depolymerization. Microtubule reorganization also plays an important role in cell migration and polarization. Intermediate filaments are rearranged, switching to a vimentin-rich network, and this protein is used as a marker for a mesenchymal cell. Hence, targeting EMT by regulating the activities of their key components may be a potential solution to metastasis. This review summarizes the research done on the physiological functions of the cytoskeleton, its role in the EMT process, and its effect on multidrug-resistant (MDR) cancer cells—highlight some future perspectives in cancer therapy by targeting cytoskeleton.
Periostin Short Fragment with Exon 17 via Aberrant Alternative Splicing Is Required for Breast Cancer Growth and Metastasis
Authors: Ikeda-Iwabu Yuka , Taniyama Yoshiaki , Katsuragi Naruto , Sanada Fumihiro , Koibuchi Nobutaka , Shibata Kana , Shimazu Kenzo , Rakugi Hiromi , Morishita Ryuichi
Published: April 2021

Background: Periostin (POSTN) is a 93 kDa matrix protein that helps to regulate collagen gene expression in the extracellular matrix. POSTN overexpression is a prognostic factor in malignant cancers; however, some researchers have observed it in the stroma, whereas others have reported it on tumors. Objective: This study aimed to investigate the function of POSTN on tumors. Methods and Results: We found that POSTN in cancer cells can be detected by using an antibody against the POSTN C-terminal region exon 17 (Ex17 antibody), but not with an antibody against the POSTN N-terminal region exon 12 (Ex12 antibody) in patients with breast cancer. In a fraction secreted from fibroblasts, LC–MS/MS analysis revealed a short fragment of POSTN of approximately 40 kDa with exon 17. In addition, molecular interaction analysis showed that POSTN with exon 17, but not POSTN without exon 17, bound specifically to wnt3a, and the Ex17 antibody inhibited the binding. Conclusion: A short fragment of POSTN with exon 17, which originates in the fibroblasts, is transported to cancer cells, whereas POSTN fragments without exon 17 are retained in the stroma. The Ex17 antibody inhibits the binding between POSTN exon 17 and wnt3a.
The Role of Macrophages in the Development of Acute and Chronic Inflammatory Lung Diseases
Authors: Lee Jae-Won , Chun Wanjoo , Lee Hee Jae , Min Jae-Hong , Kim Seong-Man , Seo Ji-Yun , Ahn Kyung-Seop , Oh Sei-Ryang
Published: April 2021

Macrophages play an important role in the innate and adaptive immune responses of organ systems, including the lungs, to particles and pathogens. Cumulative results show that macrophages contribute to the development and progression of acute or chronic inflammatory responses through the secretion of inflammatory cytokines/chemokines and the activation of transcription factors in the pathogenesis of inflammatory lung diseases, such as acute lung injury (ALI), acute respiratory distress syndrome (ARDS), ARDS related to COVID-19 (coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)), allergic asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). This review summarizes the functions of macrophages and their associated underlying mechanisms in the development of ALI, ARDS, COVID-19-related ARDS, allergic asthma, COPD, and IPF and briefly introduces the acute and chronic experimental animal models. Thus, this review suggests an effective therapeutic approach that focuses on the regulation of macrophage function in the context of inflammatory lung diseases.
Considerations to Model Heart Disease in Women with Preeclampsia and Cardiovascular Disease
Authors: Liu Chung Ming Clara , Sesperez Kimberly , Ben-Sefer Eitan , Arpon David , McGrath Kristine , McClements Lana , Gentile Carmine
Published: April 2021

Preeclampsia is a multifactorial cardiovascular disorder diagnosed after 20 weeks of gestation, and is the leading cause of death for both mothers and babies in pregnancy. The pathophysiology remains poorly understood due to the variability and unpredictability of disease manifestation when studied in animal models. After preeclampsia, both mothers and offspring have a higher risk of cardiovascular disease (CVD), including myocardial infarction or heart attack and heart failure (HF). Myocardial infarction is an acute myocardial damage that can be treated through reperfusion; however, this therapeutic approach leads to ischemic/reperfusion injury (IRI), often leading to HF. In this review, we compared the current in vivo, in vitro and ex vivo model systems used to study preeclampsia, IRI and HF. Future studies aiming at evaluating CVD in preeclampsia patients could benefit from novel models that better mimic the complex scenario described in this article.
Emotion Regulation with Parents and Friends and Adolescent Internalizing and Externalizing Behavior
Authors: Lindsey Eric W.
Published: April 2021

This study examined adolescents’ self-reported use of emotion regulation strategies with parents and friends in relation to internalizing and externalizing behavior. A total of 185 children aged 13–14 years old (91 girls, 94 boys) completed three surveys to assess their emotion regulation strategies with mothers, fathers and best friends. Parents completed surveys assessing adolescents’ internalizing and externalizing behavior. Regression analysis revealed that adolescents’ self-reported ER with mothers and fathers and friends made independent contributions to parent reports of youth internalizing and externalizing behavior. Adolescents who reported engaging in more emotion suppression with friends had higher internalizing scores, whereas adolescents who reported more affective expression with friends had lower internalizing scores. Self-reported emotion regulation strategies with mothers and fathers were unrelated to internalizing behavior. Adolescents who reported engaging in higher levels of affective suppression and cognitive reappraisal with their mothers and fathers had lower parental ratings of externalizing behavior. Emotion regulation strategies with best friends were unrelated to externalizing behavior.
Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite
Authors: Zhang Kuai , Li Yungang , Yan Hongyan , Wang Chuang , Li Hui , Liang Jinglong , Dang Jie
Published: April 2021

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.
Feasibility, Reproducibility and Validation of Right Ventricular Volume and Function Assessment Using Three-Dimensional Echocardiography
Authors: De Potter Tom , Weytjens Caroline , Motoc Andreea , Luchian Maria Luiza , Scheirlynck Esther , Roosens Bram , Tanaka Kaoru , Houard Laura , Droogmans Steven , Cosyns Bernard
Published: April 2021

Three-dimensional echocardiography (3DE) is advised for right ventricular (RV) assessment. Data regarding the optimal acquisition settings and optimization are still scarce. We aimed to evaluate the feasibility, reproducibility and validation of 3DE for RV volume and function assessment, using cardiac magnetic resonance (CMR) as gold standard. Thirty healthy volunteers and 36 consecutive patients were prospectively included. CMR was performed in the latter. Standard apical four-chamber view (A4CV), focused A4CV and modified A4CV were used for 3DE RV acquisition. Feasibility (and the effect of changes in settings) was evaluated. Intra and interobserver analyses were performed by three observers (expert vs. novice). RV parameters by echocardiography were compared to CMR. Feasibility of acquisition was 16.7% for A4CV, 80.0% for focused A4CV and 16.7% for modified A4CV. Changes in settings had no significant influence on feasibility and further analysis. Intraobserver variability was good in both expert and novice, interobserver variability was good between experienced observers. Compared to CMR, 3DE volumes were significantly lower with fair to moderate correlation (EDV: 91.1 ± 24.4 mL vs. 144.3 ± 43.0 mL (p < 0.001), r = 0.653 and ESV: 48.1 ± 16.4 mL vs. 60.4 ± 21.2 mL (p < 0.001), r = 0.530, by multi-beat 3DE and CMR respectively). These findings suggest that standardization is needed in order to implement this technique in clinical practice, thus further studies are required.
Nucleic Acid-Based Lateral Flow Biosensor for Salmonella Typhi and Salmonella Paratyphi: A Detection in Stool Samples of Suspected Carriers
Authors: Amalina Zulkiply Nor , Khalid Muhammad Fazli , Rahman Sjafri Faizul , Ahmad Muhamad Nuramin , Ahmad Najib Mohamad , Ismail Asma , Aziah Ismail
Published: April 2021

A multiplex rapid detection system, based on a PCR-lateral flow biosensor (mPCR-LFB) was developed to identify Salmonella Typhi and Salmonella Paratyphi A from suspected carriers. The lower detection limit for S. Typhi and S. Paratyphi A was 0.16 and 0.08 ng DNA equivalent to 10 and 102 CFU/mL, respectively. Lateral flow biosensor was used for visual detection of mPCR amplicons (stgA, SPAint, ompC, internal amplification control) by labeling forward primers with fluorescein-isothiocyanate (FITC), Texas Red, dinitrophenol (DNP) and digoxigenin (DIG) and reverse primers with biotin. Binding of streptavidin-colloidal gold conjugate with the amplicons resulted in formation of a red color dots on the strip after 15–20 min of sample exposure. The nucleic acid lateral flow analysis of the mPCR-LFB was better in sensitivity and more rapid than the conventional agarose gel electrophoresis. Moreover, the mPCR-LFB showed 100% sensitivity and specificity when evaluated with stools spiked with 100 isolates of Salmonella genus and other bacteria. A prospective cohort study on stool samples of 1176 food handlers in outbreak areas (suspected carriers) resulted in 23 (2%) positive for S. Typhi. The developed assay has potential to be used for rapid detection of typhoid carriers in surveillance program.
Evaluation of the Potential Diagnostic Utility of the Determination of Selected Caspases—Markers Involved in the Regulation of Apoptosis—In Patients with Ovarian Cancer
Authors: Mielczarek-Palacz Aleksandra , Jasińska Sylwia , Strzelec Anna
Published: April 2021

Ovarian cancer remains a major diagnostic and therapeutic problem in modern gynecological oncology. For this reason, research which focuses on the search for new diagnostic markers and the assessment of their possible usefulness in clinical practice is still being conducted. The aim of this study was to evaluate serum levels of caspase-3, caspase-8, and caspase-9 in women with ovarian cancer. Patients with ovarian serous cystadenoma (Cystadenoma serosum) and papillary serous cystadenocarcinoma (Cystadenocarcinoma papillare serosum IIIC) were included in the study, as well as healthy women who constituted the control group. The results of the study revealed a statistically significantly decreased mean serum levels of caspase-3, caspase-8, and caspase-9 in women with ovarian cancer as compared to the control group (p ˂ 0.001), which indicates the involvement of the studied parameters in immune system disturbances occurring in the process of apoptosis by the extrinsic and intrinsic pathway and may be one of the mechanisms of immunosuppression accompanying these tumors. Determination of serum levels of examined caspases and CA 125 antigen in women with ovarian cancer in combination with other markers may prove useful in the future in the diagnosis of ovarian cancer, but this requires further studies.
Adaptive Diagnosis for Fault Tolerant Data Fusion Based on α-Rényi Divergence Strategy for Vehicle Localization
Authors: Makkawi Khoder , Ait-Tmazirte Nourdine , El Badaoui El Najjar Maan , Moubayed Nazih
Published: April 2021

When applying a diagnostic technique to complex systems, whose dynamics, constraints, and environment evolve over time, being able to re-evaluate the residuals that are capable of detecting defaults and proposing the most appropriate ones can quickly prove to make sense. For this purpose, the concept of adaptive diagnosis is introduced. In this work, the contributions of information theory are investigated in order to propose a Fault-Tolerant multi-sensor data fusion framework. This work is part of studies proposing an architecture combining a stochastic filter for state estimation with a diagnostic layer with the aim of proposing a safe and accurate state estimation from potentially inconsistent or erroneous sensors measurements. From the design of the residuals, using α-Rényi Divergence (α-RD), to the optimization of the decision threshold, through the establishment of a function that is dedicated to the choice of α at each moment, we detail each step of the proposed automated decision-support framework. We also dwell on: (1) the consequences of the degree of freedom provided by this α parameter and on (2) the application-dictated policy to design the α tuning function playing on the overall performance of the system (detection rate, false alarms, and missed detection rates). Finally, we present a real application case on which this framework has been tested. The problem of multi-sensor localization, integrating sensors whose operating range is variable according to the environment crossed, is a case study to illustrate the contributions of such an approach and show the performance.
Analysis of Instability Behavior and Mechanism of E-Mode GaN Power HEMT with p-GaN Gate under Off-State Gate Bias Stress
Authors: Elangovan Surya , Chang Edward Yi , Cheng Stone
Published: April 2021

In this study, we investigate the degradation characteristics of E-mode GaN High Electron Mobility Transistors (HEMTs) with a p-GaN gate by designed pulsed and prolonged negative gate (VGS) bias stress. Device transfer and transconductance, output, and gate-leakage characteristics were studied in detail, before and after each pulsed and prolonged negative VGS bias stress. We found that the gradual degradation of electrical parameters, such as threshold voltage (VTH) shift, on-state resistance (RDS-ON) increase, transconductance max (Gm, max) decrease, and gate leakage current (IGS-Leakage) increase, is caused by negative VGS bias stress time evolution and magnitude of stress voltage. The significance of electron trapping effects was revealed from the VTH shift or instability and other parameter degradation under different stress voltages. The degradation mechanism behind the DC characteristics could be assigned to the formation of hole deficiency at p-GaN region and trapping process at the p-GaN/AlGaN hetero-interface, which induces a change in the electric potential distribution at the gate region. The design and application of E-mode GaN with p-GaN gate power devices still need such a reliability investigation for significant credibility.
Power-Generation Optimization Based on Piezoelectric Ceramic Deformation for Energy Harvesting Application with Renewable Energy
Authors: Han Hyeonsu , Ko Junghyuk
Published: April 2021

Along with the increase in renewable energy, research on energy harvesting combined with piezoelectric energy is being conducted. However, it is difficult to predict the power generation of combined harvesting because there is no data on the power generation by a single piezoelectric material. Before predicting the corresponding power generation and efficiency, it is necessary to quantify the power generation by a single piezoelectric material alone. In this study, the generated power is measured based on three parameters (size of the piezoelectric ceramic, depth of compression, and speed of compression) that contribute to the deformation of a single PZT (Lead zirconate titanate)-based piezoelectric element. The generated power was analyzed by comparing with the corresponding parameters. The analysis results are as follows: (i) considering the difference between the size of the piezoelectric ceramic and the generated power, 20 mm was the most efficient piezoelectric ceramic size, (ii) considering the case of piezoelectric ceramics sized 14 mm, the generated power continued to increase with the increase in the compression depth of the piezoelectric ceramic, and (iii) For piezoelectric ceramics of all diameters, the longer the depth of deformation, the shorter the frequency, and depending on the depth of deformation, there is a specific frequency at which the charging power is maximum. Based on the findings of this study, PZT-based elements can be applied to cases that receive indirect force, including vibration energy and wave energy. In addition, the power generation of a PZT-based element can be predicted, and efficient conditions can be set for maximum power generation.
Energy and Exergy Analyses of Adsorption Chiller at Various Recooling-Water and Dead-State Temperatures
Authors: Alsarayreh Ahmad A. , Al-Maaitah Ayman , Attarakih Menwer , Bart Hans-Jörg
Published: April 2021

We conducted energy and exergy analyses of an adsorption chiller to investigate the effect of recooling-water temperatures on the cooling capacity and Coefficient of Performance (COP) with variable cycle modes. We investigated both the effect of the recooling-water temperature and the dead state temperature on the exergy destruction in the chiller components. Our results show that there is an optimum reheat cycle mode for each recooling-water temperature range. For the basic single stage cycle, the exergy destruction is mainly accrued in the desorber (49%), followed by the adsorber (27%), evaporator (13%), condenser (9%), and expansion valve (2%). The exergy destruction for the preheating process is approximately 35% of the total exergy destruction in the desorber. By contrast, the precooling process is almost 58% of the total exergy destruction in the adsorber. The exergy destruction decreases when increasing the recooling-water and the dead state temperatures, while the exergy efficiency increases. Nonetheless, the exergy efficiency decreases with an increase in the recooling-water temperature at fixed dead state temperatures. The effect of the mass recovery time in the reheat cycle on exergy destruction was also investigated, and the results show that the exergy destruction increases when the mass recovery time increases. The exergy destruction in the adsorbent beds was the most sensitive to the increase in mass recovery time.
Impact of Lorentz Force in Thermally Developed Pulsatile Micropolar Fluid Flow in a Constricted Channel
Authors: Umar Muhammad , Ali Amjad , Bukhari Zainab , Shahzadi Gullnaz , Saleem Arshad
Published: April 2021

This work aimed to analyze the heat transfer of micropolar fluid flow in a constricted channel influenced by thermal radiation and the Lorentz force. A finite difference-based flow solver, on a Cartesian grid, is used for the numerical solution after transforming the governing equations into the vorticity-stream function form. The impact of various emerging parameters on the wall shear stress, axial velocity, micro-rotation velocity and temperature profiles is discussed in this paper. The temperature profile is observed to have an inciting trend towards the thermal radiation, whereas it has a declining trend towards the Hartman and Prandtl numbers. The axial velocity profile has an inciting trend towards the Hartman number, whereas it has a declining trend towards the micropolar parameter and Reynolds number. The micro-rotation velocity escalates with the micropolar parameter and Hartman number, whereas it de-escalates with the Reynolds number. The Nusselt number is observed to have a direct relationship with the Prandtl and Reynolds numbers.
Low-Cost Organic Adsorbents for Elemental Mercury Removal from Lignite Flue Gas
Authors: Marczak-Grzesik Marta , Budzyń Stanisław , Tora Barbara , Szufa Szymon , Kogut Krzysztof , Burmistrz Piotr
Published: April 2021

The research presented by the authors in this paper focused on understanding the behavior of mercury during coal combustion and flue gas purification operations. The goal was to determine the flue gas temperature on the mercury emissions limits for the combustion of lignites in the energy sector. The authors examined the process of sorption of mercury from flue gases using fine-grained organic materials. The main objectives of this study were to recommend a low-cost organic adsorbent such as coke dust (CD), corn straw char (CS-400), brominated corn straw char (CS-400-Br), rubber char (RC-600) or granulated rubber char (GRC-600) to efficiently substitute expensive dust-sized activated carbon. The study covered combustion of lignite from a Polish field. The experiment was conducted at temperatures reflecting conditions inside a flue gas purification installation. One of the tested sorbents—tire-derived rubber char that was obtained by pyrolysis—exhibited good potential for Hg0 into Hg2+ oxidation, resulting in enhanced mercury removal from the flue. The char characterization increased elevated bromine content (mercury oxidizing agent) in comparison to the other selected adsorbents. This paper presents the results of laboratory tests of mercury sorption from the flue gases at temperatures of 95, 125, 155 and 185 °C. The average mercury content in Polish lignite was 465 μg·kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 17.8 µg·m−3. The study analyzed five low-cost sorbents with the average achieved efficiency of mercury removal from 18.3% to 96.1% for lignite combustion depending on the flue gas temperature.
A Comparative Study on the Performance of Single and Multi-Layer Encapsulated Phase Change Material Packed-Bed Thermocline Tanks
Authors: Guo Huiqian , ELSihy ELSaeed Saad , Liao Zhirong , Du Xiaoze
Published: April 2021

This paper presents a numerical study that aims at investigating the effects of different parameters on the dynamic performance of single and multi-layer encapsulated phase material (PCM) thermocline tanks. A transient, one-dimensional, two-phase, concentric-dispersion model is formulated to evaluate such performance. Encapsulated paraffin waxes having different melting-points are used as PCMs, with water as heat transfer fluid. Comprehensive comparisons between single-PCM and multiple-PCMs systems are numerically analyzed first. Second, the effects of the PCM volume fraction (VF) and the inverse Stefan number have been discussed. The results show that among the various cases the single-PCM70 system has the highest performance in terms of charging and discharging efficiency, followed by a multiple-PCMs system with average performance. Compared with the PCM40 case, the PCM70 case has a 29% increase in the output energy from the system. The VF of PCMs influences the system output, both in terms of energy storage and release, the heat storage period and the total energy stored increased by 4.5%, when the VF of the PCM70 increases from 33.33% to 50%, respectively. Furthermore, it increases the system’s overall efficiency and total utilization ratio by 13.7% and 25%, respectively, when compared to the arrangement in which the PCM40 occupies 50% of the total bed height. The effect of the inverse Stefan number has a significant impact on the system’s utilization ratio. Compared with all other 3-PCM systems, the scenario with the lowest inverse Stefan number in the middle PCM has the highest charging and discharging efficiencies of 83.9% and 80.8%, respectively. The findings may be beneficial for the design and optimization of packed-bed tanks.
A Powerful Tool for Optimal Control of Energy Systems in Sustainable Buildings: Distortion Power Bivector
Authors: Manuel V. Castilla , Francisco Martin
Published: April 2021

In the field of building constructions, there is undeniably a growing need to optimize the energy systems which are a key target in new modern constructions and industrial buildings. In this sense, energy systems are being traced for the development of energy distribution networks that are increasingly smart, efficient, and sustainable. Modern generation and distribution energy systems, such as microgrids control systems, are being affected by the presence of linear and nonlinear loads, resulting a distorted voltage and current waveforms. Thus, it is stated that industrial and residential building heating and cooling loads behave essentially like sources of harmonics. This paper presents a new framework based on geometric algebra (GA) to the definition of a multivectorial distortion power concept, which is represented by a bivector that is geometrically interpreted to distinguish the rotated distortion and distortion power bivectors in these kinds of loads. Both bivectors, and their relations to the phase angles of distorted voltage are the main subject of this paper to interpret an optimal control of building energy. Numerical examples are used to illustrate of the suggested distortion power concept, as well as the information it provides for energy control in new buildings in a more sustainable way.
Extension of Pin-Based Point-Wise Energy Slowing-Down Method for VHTR Fuel with Double Heterogeneity
Authors: Han Tae-Young , Cho Jin-Young , Jo Chang-Keun , Lee Hyun-Chul
Published: April 2021

For the resonance treatment of a very high temperature reactors (VHTR) fuel with the double heterogeneity, an extension of the pin-based pointwise energy slowing-down method (PSM) was developed and implemented into DeCART. The proposed method, PSM-double heterogeneity (DH), has an improved spherical unit cell model with an explicit tri-structural isotropic (TRISO) model, a matrix layer, and a moderator for reflecting the moderation effect. The moderator volume was analytically derived using the relation of the Dancoff factor and the mean chord length. In the first step, the pointwise homogenized cross-sections for the compact was obtained after solving the slowing down equation for the spherical unit cell. Then, the shielded cross-section for the homogenized fuel compact was generated using the original PSM. The verification calculations were performed for the fuel pins with various packing fractions, compact sizes, TRISO sizes, and fuel temperatures. Additionally, two fuel block problems with very different sizes were examined and the depletion calculation was carried out for investigating the accuracy of the proposed method. They revealed that the PSM-DH has a good performance in the VHTR problems.
Deep Learning-Based Approaches to Optimize the Electricity Contract Capacity Problem for Commercial Customers
Authors: Nafkha Rafik , Ząbkowski Tomasz , Gajowniczek Krzysztof
Published: April 2021

The electricity tariffs available to customers in Poland depend on the connection voltage level and contracted capacity, which reflect the customer demand profile. Therefore, before connecting to the power grid, each consumer declares the demand for maximum power. This amount, referred to as the contracted capacity, is used by the electricity provider to assign the proper connection type to the power grid, including the size of the security breaker. Maximum power is also the basis for calculating fixed charges for electricity consumption, which is controlled and metered through peak meters. If the peak demand exceeds the contracted capacity, a penalty charge is applied to the exceeded amount, which is up to ten times the basic rate. In this article, we present several solutions for entrepreneurs based on the implementation of two-stage and deep learning approaches to predict maximal load values and the moments of exceeding the contracted capacity in the short term, i.e., up to one month ahead. The forecast is further used to optimize the capacity volume to be contracted in the following month to minimize network charge for exceeding the contracted level. As confirmed experimentally with two datasets, the application of a multiple output forecast artificial neural network model and a genetic algorithm (two-stage approach) for load optimization delivers significant benefits to customers. As an alternative, the same benefit is delivered with a deep learning architecture (hybrid approach) to predict the maximal capacity demands and, simultaneously, to determine the optimal capacity contract.
Heat Transfer Optimization of NEXA Ballard Low-Temperature PEMFC
Authors: Chesalkin Artem , Kacor Petr , Moldrik Petr
Published: April 2021

Hydrogen is one of the modern energy carriers, but its storage and practical use of the newest hydrogen technologies in real operation conditions still is a task of future investigations. This work describes the experimental hydrogen hybrid energy system (HHS). HHS is part of a laboratory off-grid system that stores electricity gained from photovoltaic panels (PVs). This system includes hydrogen production and storage units and NEXA Ballard low-temperature proton-exchange membrane fuel cell (PEMFC). Fuel cell (FC) loses a significant part of heat during converting chemical energy into electricity. The main purpose of the study was to explore the heat distribution phenomena across the FC NEXA Ballard stack during load with the next heat transfer optimization. The operation of the FC with insufficient cooling can lead to its overheating or even cell destruction. The cause of this undesirable state is studied with the help of infrared thermography and computational fluid dynamics (CFD) modeling with heat transfer simulation across the stack. The distribution of heat in the stack under various loads was studied, and local points of overheating were determined. Based on the obtained data of the cooling air streamlines and velocity profiles, few ways of the heat distribution optimization along the stack were proposed. This optimization was achieved by changing the original shape of the FC cooling duct. The stable condition of the FC stack at constant load was determined.
Cellulosic Bioethanol from Industrial Eucalyptus globulus Bark Residues Using Kraft Pulping as a Pretreatment
Authors: Amândio Mariana S. T. , Rocha Jorge M. S. , Serafim Luísa S. , Xavier Ana M. R. B.
Published: April 2021

The pulp and paper industry faces an emerging challenge for valorising wastes and side-streams generated according to the biorefinery concept. Eucalyptus globulus bark, an abundant industrial residue in the Portuguese pulp and paper sector, has a high potential to be converted into biobased products instead of being burned. This work aimed to evaluate the ethanol production from E. globulus bark previously submitted to kraft pulping through separate hydrolysis and fermentation (SHF) configuration. Fed-batch enzymatic hydrolysis provided a concentrated hydrolysate with 161.6 g·L−1 of cellulosic sugars. S. cerevisiae and Ethanol Red® strains demonstrated a very good fermentation performance, despite a negligible xylose consumption. S. passalidarum, a yeast known for its capability to consume pentoses, was studied in a simultaneous co-culture with Ethanol Red®. However, bioethanol production was not improved. The best fermentation performance was achieved by Ethanol Red®, which provided a maximum ethanol concentration near 50 g·L−1 and fermentation efficiency of 80%. Concluding, kraft pulp from E. globulus bark showed a high potential to be converted into cellulosic bioethanol, being susceptible to implementing an integrated biorefinery on the pulp and paper industrial plants.
“Green Energy” and the Standard of Living of the EU Residents
Authors: Malinowski Mariusz
Published: April 2021

The author intended to present the relationship between the standard of living of EU citizens and the level of the development of renewable energy. It is particularly important in the context of the implementation of the sustainable development idea, by ensuring a high standard of living for both current and future generations, with rational use of available natural resources. The first, theoretical part of the article presents the problem related to the impact of renewable energy on the standard of living in a synthetic way. The second part involves empirical research conducted in all countries of the EU. To evaluate the level of renewable energy development and the standard of living, the author constructed original measures based on the TOPSIS method. Variables were selected on the basis of substantive, statistical and formal criteria (primarily the completeness and availability of data in 2019). Within the framework of the conducted study, the author obtained, among other things, a relatively high value of Spearman’s rank correlation coefficient between the constructed synthetic measures (0.47). Canonical analysis was used to identify the relationship between them. Numerous indicators, including canonical correlations, complete redundancy and extracted variances, were determined with the use of canonical analysis. Seven statistically significant canonical variables were identified. The value of the greatest and most statistically significant canonical correlation exceeded 0.94, and for the last statistically significant canonical variable, the value reached over 0.31. Statistical data were primarily obtained from the publicly available EUROSTAT database.
Multiple Input Multiple Output Resonant Inductive WPT Link: Optimal Terminations for Efficiency Maximization
Authors: Monti Giuseppina , Mongiardo Mauro , Minnaert Ben , Costanzo Alessandra , Tarricone Luciano
Published: April 2021

In this paper a general-purpose procedure for optimizing a resonant inductive wireless power transfer link adopting a multiple-input-multiple-output (MIMO) configuration is presented. The wireless link is described in a general–purpose way as a multi-port electrical network that can be the result of either analytical calculations, full–wave simulations, or measurements. An eigenvalue problem is then derived to determine the link optimal impedance terminations for efficiency maximization. A step-by-step procedure is proposed to solve the eigenvalue problem using a computer algebra system, it provides the configuration of the link, optimal sources, and loads for maximizing the efficiency. The main advantage of the proposed approach is that it is general: it is valid for any strictly–passive multi–port network and is therefore applicable to any wireless power transfer (WPT) link. To validate the presented theory, an example of application is illustrated for a link using three transmitters and two receivers whose impedance matrix was derived from full-wave simulations.
Spatiotemporal Dynamics of Urban Green Space Influenced by Rapid Urbanization and Land Use Policies in Shanghai
Authors: Liu Song , Zhang Xinsu , Feng Yongjiu , Xie Huan , Jiang Li , Lei Zhenkun
Published: April 2021

Urbanization has led to the continuous expansion of built-up areas and the ever-growing urban population, threatening the quantity and quality of urban green space (UGS). Exploring the spatiotemporal variations of UGS is substantially conducive to the formulation of land-use policies to protect the ecosystems. As one of the largest megacities all around the world, Shanghai has experienced rapid urbanization in the past three decades. Insights into how UGS changes in response to urbanization and greening policies are essential for guiding sustainable urban development. This paper employed integrated approaches to characterize the changing patterns and intensities of green space in Shanghai, China from 1990 to 2015. The spatiotemporal dynamics of the UGS pattern were derived through four main methods: green space ratio, dynamic change degree (DCD), transition matrix and landscape metrics. The results showed that Shanghai’s green space decreased from 84.8% in 1990 to 61.9% in 2015 while the built-up areas increased from 15.0% to 36.5%. Among the green space sub-types, farmland was largely encroached and fragmented by urban sprawl, especially in the Outer Ring Expressway and Suburban Ring Expressway belts of the city. About 1522 km2 of the green space has transferred into built-up areas, followed by farmland, waterbody, forest, and grassland in descending order. The 2000–2010 period witnessed the strong urban expansion and dramatic changes in UGS, but then the change around 2015 turned down and stable. The landscape pattern metrics showed that the entire green space in Shanghai was growingly fragmented and isolated during the past 25 years. Combined with the green space-related planning and policies issued in 1990–2015, the results revealed that both rapid urbanization and greening policies accounted for the spatiotemporal dynamics of UGS. Based on the results, some implicants to new urban planning and policies of Shanghai were highlighted.
A Methodology for Optimizing Tenon Geometry Dimensions of Mortise-and-Tenon Joint Wood Products
Authors: Hu Wengang , Chen Bingrui
Published: April 2021

For a long time, the geometry dimensions of tenons have been designed through empirical methods, which is not beneficial to designers and manufacturers and results in more time spent in construction and a greater amount of waste wood materials. In this study, an optimal methodology of combining finite element analysis (FEA) with response surface method (RSM) was proposed to investigate the effect of tenon geometric dimensions (length, width, and thickness) on withdrawal and bending load capacities of mortise-and-tenon (M-T) joints, with the aim of making the design of wood products more scientific. The following results were concluded: (1) the effect of tenon length on withdrawal load capacity was greater than tenon thickness, followed by tenon width; (2) the effect of tenon thickness on bending load capacity was greater than those of tenon width, followed by tenon length; (3) it was concluded that the tenon length should be designed to be greater than the tenon width and smaller than twice the tenon width, especially, when tenon thickness was relatively thin; (4) quadratic models can be used to predict the withdrawal and bending load capacities of M-T joints relating the length, width, and thickness of the tenon; (5) the proposed method was capable of being used to optimize the tenon sizes and get more knowledge of M-T joints visually. This study will contribute to reducing the costs of time and materials, and it will result in M-T joints being designed more rationally.
Oscillating Magnetohydrodynamic Stokes Flow between Porous Plates with Spatiotemporally Periodic Reabsorption
Authors: Raptis Anastasios , Manopoulos Christos , Xenos Michalis , Tsangaris Sokrates
Published: April 2021

The study addresses the oscillating magnetohydrodynamic (MHD) Stokes flow between two parallel plates with periodic reabsorption both spatially and temporally. Two cases are distinguished by applying either (1) transverse or (2) parallel external magnetic field. Analytical solutions of velocity and pressure are derived for both cases and the effect of Womersley and Hartmann number, and the absorption coefficient is examined. The study generalizes existing literature on analytic MHD Stokes flow solutions accounting for periodic boundary conditions both in time and space. The non-oscillating non-MHD Stokes flow in a porous channel (available in the literature) is proven to be a limit of the analytic solution introduced here. The MHD effects are noticeable in flows oscillating with low or moderate frequency but are barely detectable in high-frequency flows even in the presence of strong magnetic fields.
Relationships between Structure and Antioxidant Capacity and Activity of Glycosylated Flavonols
Authors: Xiao Zhengcao , He Liangliang , Hou Xiaohui , Wei Jianping , Ma Xiaoyu , Gao Zihan , Yuan Yahong , Xiao Jianbo , Li Pengmin , Yue Tianli
Published: April 2021

The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC under most conditions due to substitution of the 3-position hydroxyl group and glycoside disruption in the molecular planarity. The 7-glycosylated derivatives did not have the above effects, thus generally exhibited ACs similar to their aglycones. Glycosylation decreased the AA of kaempferol and isorhamnetin for both assays in methanol, 3-glycosylation inhibited quercetin AA in the ABTS assay. In the DPPH assay, the AA of 3-glycosylated quercetin was significantly higher than quercetin. Using LC–MS/MS analysis, we found that quercetin and quercetin-7-glucoside underwent dimerization during the antioxidant reaction, potentially leading to a decline in AAs. However, 3-glycoside substitution may have hindered dimer formation, thereby allowing the FLVs to retain strong free radical scavenging abilities.
A New Food Composition Database of Lactose-Free Products Commercialized in Spain: Differences in Nutritional Composition as Compared to Traditional Products
Authors: Martínez Rodríguez María , Samaniego-Vaesken Mᵃ de Lourdes , Alonso-Aperte Elena
Published: April 2021

We developed a new database to evaluate the nutritional composition of lactose-free products from Spain. The database includes dairy products and other products, all of which show the “lactose-free” declaration on their label, accounting for 327 products in total. Of these, 123 are dairy products, 16 are non-dairy products which include a dairy ingredient (5%) and 188 items (57% of the sample) are non-dairy products that do not contain any dairy ingredient. The main subgroups are yogurt (25%), milk (24%), and cheese (17%). Nineteen percent of the compiled products included nutritional claims on their labels. Most lactose-free products did not contain either added sugars or low- or no-calorie sweeteners (58%), while 34% included added sugars and only 6%, sweeteners or a combination of both (2%). We found that 19.5%, mainly within the milk subgroup, were fortified with vitamins A, D, E, K, B9, and B12, P, and Ca. There were no significant differences in the nutritional composition between lactose-free products and traditional products. According to the NOVA classification, 55% of compiled lactose-free products were ultra-processed, and 20% processed. The array of lactose-free products marketed in Spain proves that there are enough, both in quantity and quality, to satisfy the dairy needs of lactose intolerants.