bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Time-Delay Side-Collision Warning Model at Non-Signalized Intersections Based on Vehicle-to-Infrastructure Communication
Authors: Lyu Nengchao , Wen Jiaqiang , Wu Chaozhong
Published: February 2021

In complex traffic environments, collision warning systems that rely only on in-vehicle sensors are limited in accuracy and range. Vehicle-to-infrastructure (V2I) communication systems, however, offer more robust information exchange, and thus, warnings. In this study, V2I was used to analyze side-collision warning models at non-signalized intersections: A novel time-delay side-collision warning model was developed according to the motion compensation principle. This novel time-delay model was compared with and verified against a traditional side-collision warning model. Using a V2I-oriented simulated driving platform, three vehicle-vehicle collision scenarios were designed at non-signalized intersections. Twenty participants were recruited to conduct simulated driving experiments to test and verify the performance of each collision warning model. The results showed that compared with no warning system, both side-collision warning models reduced the proportion of vehicle collisions. In terms of efficacy, the traditional model generated an effective warning in 84.2% of cases, while the novel time-delay model generated an effective warning in 90.2%. In terms of response time and conflict time difference, the traditional model gave a longer response time of 0.91 s (that of the time-delay model is 0.78 s), but the time-delay model reduced the driving risk with a larger conflict time difference. Based on an analysis of driver gaze change post-warning, the statistical results showed that the proportion of effective gaze changes reached 84.3%. Based on subjective evaluations, drivers reported a higher degree of acceptance of the time-delay model. Therefore, the time-delay side-collision warning model for non-signalized intersections proposed herein can improve the applicability and efficacy of warning systems in such complex traffic environments and provide reference for safety applications in V2I systems.
Acute Effects of a Single Bout of Walking on Affective Responses in Patients with Major Depressive Disorder
Authors: Niedermeier Martin , Ledochowski Larissa , Leitner Hartmann , Zingerle Helmut , Kopp Martin
Published: February 2021

Exercise programs are considered an effective (add-on) treatment option for depressive disorders. However, little is known about the acute effects of exercise on affective responses in in-patient settings. Therefore, the aim of the present study was to compare the effects of a single 30-min bout of walking on affective responses to a passive control condition in patients with major depressive disorder during treatment in a mental health center. In total, 23 in-patients were exposed to two conditions (duration: 30 min) using a within-subject design: an exercise (light–moderate walking outdoors) and a passive control condition (sitting and reading). Affective responses were assessed based on the Circumplex Model in four phases: pre, during, post, and two hours following the conditions. The main results include a significantly larger pre–post increase in energetic arousal in the exercise condition compared to the control condition, p = 0.012, ηp² = 0.25, but no significantly different pre–follow-up change between conditions, p = 0.093, ηp² = 0.12. Negatively valenced affective responses showed significantly stronger pre–post decreases after the exercise condition compared to the passive control condition, p < 0.036, ηp² > 0.18. Positively valenced affective response activity showed a pre–post increase in the exercise condition and a pre–post decrease in the passive control condition, p = 0.017, ηp² = 0.23. The higher-activated, positively valenced immediate response of light- to moderate-intensity walking may serve as an acute emotion regulation in patients with major depressive disorder and provide a favorable state for adherence to exercise programs.
Cytokinesis in fra2 Arabidopsis thaliana p60-Katanin Mutant: Defects in Cell Plate/Daughter Wall Formation
Authors: Panteris Emmanuel , Kouskouveli Anna , Pappas Dimitris , Adamakis Ioannis-Dimosthenis S.
Published: January 2021

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast have been reported to occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), in root cells of the fra2 Arabidopsis thaliana loss-of-function mutant. In addition, deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls also appeared faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.
Design and Synthesis of N-Substituted 3,4-Pyrroledicarboximides as Potential Anti-Inflammatory Agents
Authors: Redzicka Aleksandra , Czyżnikowska Żaneta , Wiatrak Benita , Gębczak Katarzyna , Kochel Andrzej
Published: January 2021

In the present paper, we describe the biological activity of the newly designed and synthesized series N-substituted 3,4-pyrroledicarboximides 2a–2p. The compounds 2a–2p were obtained in good yields by one-pot, three-component condensation of pyrrolo[3,4-c]pyrrole scaffold (1a–c) with secondary amines and an excess of formaldehyde solution in C2H5OH. The structural properties of the compounds were characterized by 1H NMR, 13C NMR FT-IR, MS, and elemental analysis. Moreover, single crystal X-ray diffraction has been recorded for compound 2h. The colorimetric inhibitor screening assay was used to obtain their potencies to inhibit COX-1 and COX-2 enzymes. According to the results, all of the tested compounds inhibited the activity of COX-1 and COX-2. Theoretical modeling was also applied to describe the binding properties of compounds towards COX-1 and COX-2 cyclooxygenase isoform. The data were supported by QSAR study.
Differential Effects of Gold Nanoparticles and Ionizing Radiation on Cell Motility between Primary Human Colonic and Melanocytic Cells and Their Cancerous Counterparts
Authors: Shahhoseini Elham , Nakayama Masao , Piva Terrence J. , Geso Moshi
Published: January 2021

This study examined the effects of gold nanoparticles (AuNPs) and/or ionizing radiation (IR) on the viability and motility of human primary colon epithelial (CCD841) and colorectal adenocarcinoma (SW48) cells as well as human primary epidermal melanocytes (HEM) and melanoma (MM418-C1) cells. AuNPs up to 4 mM had no effect on the viability of these cell lines. The viability of the cancer cells was ~60% following exposure to 5 Gy. Exposure to 5 Gy X-rays or 1 mM AuNPs showed the migration of the cancer cells ~85% that of untreated controls, while co-treatment with AuNPs and IR decreased migration to ~60%. In the non-cancerous cell lines gap closure was enhanced by ~15% following 1 mM AuNPs or 5 Gy treatment, while for co-treatment it was ~22% greater than that for the untreated controls. AuNPs had no effect on cell re-adhesion, while IR enhanced only the re-adhesion of the cancer cell lines but not their non-cancerous counterparts. The addition of AuNPs did not enhance cell adherence. This different reaction to AuNPs and IR in the cancer and normal cells can be attributed to radiation-induced adhesiveness and metabolic differences between tumour cells and their non-cancerous counterparts.
The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease
Authors: Jacobo-Albavera Leonor , Domínguez-Pérez Mayra , Medina-Leyte Diana Jhoseline , González-Garrido Antonia , Villarreal-Molina Teresa
Published: February 2021

Cholesterol homeostasis is essential in normal physiology of all cells. One of several proteins involved in cholesterol homeostasis is the ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein widely expressed in many tissues. One of its main functions is the efflux of intracellular free cholesterol and phospholipids across the plasma membrane to combine with apolipoproteins, mainly apolipoprotein A-I (Apo A-I), forming nascent high-density lipoprotein-cholesterol (HDL-C) particles, the first step of reverse cholesterol transport (RCT). In addition, ABCA1 regulates cholesterol and phospholipid content in the plasma membrane affecting lipid rafts, microparticle (MP) formation and cell signaling. Thus, it is not surprising that impaired ABCA1 function and altered cholesterol homeostasis may affect many different organs and is involved in the pathophysiology of a broad array of diseases. This review describes evidence obtained from animal models, human studies and genetic variation explaining how ABCA1 is involved in dyslipidemia, coronary heart disease (CHD), type 2 diabetes (T2D), thrombosis, neurological disorders, age-related macular degeneration (AMD), glaucoma, viral infections and in cancer progression.
Urothelium-Specific Deletion of Connexin43 in the Mouse Urinary Bladder Alters Distension-Induced ATP Release and Voiding Behavior
Authors: Kono Jin , Ueda Masakatsu , Sengiku Atsushi , Suadicani Sylvia O. , Ogawa Osamu , Negoro Hiromitsu
Published: February 2021

Connexin43 (Cx43), the main gap junction and hemichannel forming protein in the urinary bladder, participates in the regulation of bladder motor and sensory functions and has been reported as an important modulator of day–night variations in functional bladder capacity. However, because Cx43 is expressed throughout the bladder, the actual role played by the detrusor and the urothelial Cx43 is still unknown. For this purpose, we generated urothelium-specific Cx43 knockout (uCx43KO) mice using Cre-LoxP system. We evaluated the day–night micturition pattern and the urothelial Cx43 hemichannel function of the uCx43KO mice by measuring luminal ATP release after bladder distention. In wild-type (WT) mice, distention-induced ATP release was elevated, and functional bladder capacity was decreased in the animals’ active phase (nighttime) when Cx43 expression was also high compared to levels measured in the sleep phase (daytime). These day–night differences in urothelial ATP release and functional bladder capacity were attenuated in uCx43KO mice that, in the active phase, displayed lower ATP release and higher functional bladder capacity than WT mice. These findings indicate that urothelial Cx43 mediated ATP signaling and coordination of urothelial activity are essential for proper perception and regulation of responses to bladder distension in the animals’ awake, active phase.
Ca2+-Dependent Protein Kinase 6 Enhances KAT2 Shaker Channel Activity in Arabidopsis thaliana
Authors: Ronzier Elsa , Corratgé-Faillie Claire , Sanchez Frédéric , Brière Christian , Xiong Tou Cheu
Published: February 2021

Post-translational regulations of Shaker-like voltage-gated K+ channels were reported to be essential for rapid responses to environmental stresses in plants. In particular, it has been shown that calcium-dependent protein kinases (CPKs) regulate Shaker channels in plants. Here, the focus was on KAT2, a Shaker channel cloned in the model plant Arabidopsis thaliana, where is it expressed namely in the vascular tissues of leaves. After co-expression of KAT2 with AtCPK6 in Xenopuslaevis oocytes, voltage-clamp recordings demonstrated that AtCPK6 stimulates the activity of KAT2 in a calcium-dependent manner. A physical interaction between these two proteins has also been shown by Förster resonance energy transfer by fluorescence lifetime imaging (FRET-FLIM). Peptide array assays support that AtCPK6 phosphorylates KAT2 at several positions, also in a calcium-dependent manner. Finally, K+ fluorescence imaging in planta suggests that K+ distribution is impaired in kat2 knock-out mutant leaves. We propose that the AtCPK6/KAT2 couple plays a role in the homeostasis of K+ distribution in leaves.
The Ribosome-Binding Mode of Trichothecene Mycotoxins Rationalizes Their Structure—Activity Relationships
Authors: Wang Weijun , Zhu Yan , Abraham Nadine , Li Xiu-Zhen , Kimber Matthew , Zhou Ting
Published: February 2021

Trichothecenes are the most prevalent mycotoxins contaminating cereal grains. Some of them are also considered as the virulence factors of Fusarium head blight disease. However, the mechanism behind the structure-activity relationship for trichothecenes remains unexplained. Filling this information gap is a crucial step for developing strategies to manage this large family of mycotoxins in food and feed. Here, we perform an in-depth re-examination of the existing structures of Saccharomyces cerevisiae ribosome complexed with three different trichothecenes. Multiple binding interactions between trichothecenes and 25S rRNA, including hydrogen bonds, nonpolar pi stacking interactions and metal ion coordination interactions, are identified as important binding determinants. These interactions are mainly contributed by the key structural elements to the toxicity of trichothecenes, including the oxygen in the 12,13-epoxide ring and a double bond between C9 and C10. In addition, the C3-OH group also participates in binding. The comparison of three trichothecenes binding to the ribosome, along with their binding pocket architecture, suggests that the substitutions at different positions impact trichothecenes binding in two different patterns. Moreover, the binding of trichothecenes induced conformation changes of several nucleotide bases in 25S rRNA. This then provides a structural framework for understanding the structure-activity relationships apparent in trichothecenes. This study will facilitate the development of strategies aimed at detoxifying mycotoxins in food and feed and at improving the resistance of cereal crops to Fusarium fungal diseases.
Distinctive HBV Replication Capacity and Susceptibility to Tenofovir Induced by a Polymerase Point Mutation in Hepatoma Cell Lines and Primary Human Hepatocytes
Authors: Lee Ah Ram , Cho Ju-Yeon , Kim Jong Chul , Dezhbord Mehrangiz , Choo Soo Yeun , Ahn Chang Hyun , Kim Na Yeon , Shin Jae Jin , Park Soree , Park Eun-Sook , Won Juhee , Kim Dong-Sik , Lee Jeong-Hoon , Kim Kyun-Hwan
Published: February 2021

Tenofovir disoproxil fumarate (TDF) has been regarded as the most potent drug for treating patients with chronic hepatitis B (CHB). However recently, viral mutations associated with tenofovir have been reported. Here, we found a CHB patient with suboptimal response after more than 4 years of TDF treatment. Clonal analysis of hepatitis B virus (HBV) isolated from sequential sera of this patient identified the seven previously reported TDF-resistant mutations (CYELMVI). Interestingly, a threonine to alanine mutation at the 301 amino acid position of the reverse-transcriptase (RT) domain, (rtT301A), was commonly accompanied with CYELMVI at a high rate (72.7%). Since the rtT301A mutation has not been reported yet, we investigated the role of this naturally occurring mutation on the viral replication and susceptibility to tenofovir in various liver cells (hepatoma cells as well as primary human hepatocytes). A cell-based phenotypic assay revealed that the rtT301A mutation dramatically impaired the replication ability with meaningful reduction in sensitivity to tenofovir in hepatoma cell lines. However, attenuated viral replication by the rtT301A mutation was significantly restored in primary human hepatocytes (PHHs). Our findings suggest that the replication capability and drug sensitivity of HBV is different between hepatoma cell lines and PHHs. Therefore, our study emphasizes that validation studies should be performed not only in the liver cancer cell lines but also in the PHHs to understand the exact viral fitness under antiviral pressure in patients.
Two 20-Residue-Long Peptides Derived from Plasmodium vivax Merozoite Surface Protein 10 EGF-Like Domains Are Involved in Binding to Human Reticulocytes
Authors: Ricaurte-Contreras Laura Alejandra , Lovera Andrea , Moreno-Pérez Darwin Andrés , Bohórquez Michel David , Suárez Carlos Fernando , Gutiérrez-Vásquez Elizabeth , Cuy-Chaparro Laura , Garzón-Ospina Diego , Patarroyo Manuel Alfonso
Published: February 2021

Plasmodium parasites’ invasion of their target cells is a complex, multi-step process involving many protein-protein interactions. Little is known about how complex the interaction with target cells is in Plasmodium vivax and few surface molecules related to reticulocytes’ adhesion have been described to date. Natural selection, functional and structural analysis were carried out on the previously described vaccine candidate P. vivax merozoite surface protein 10 (PvMSP10) for evaluating its role during initial contact with target cells. It has been shown here that the recombinant carboxyl terminal region (rPvMSP10-C) bound to adult human reticulocytes but not to normocytes, as validated by two different protein-cell interaction assays. Particularly interesting was the fact that two 20-residue-long regions (388DKEECRCRANYMPDDSVDYF407 and 415KDCSKENGNCDVNAECSIDK434) were able to inhibit rPvMSP10-C binding to reticulocytes and rosette formation using enriched target cells. These peptides were derived from PvMSP10 epidermal growth factor (EGF)-like domains (precisely, from a well-defined electrostatic zone) and consisted of regions having the potential of being B- or T-cell epitopes. These findings provide evidence, for the first time, about the fragments governing PvMSP10 binding to its target cells, thus highlighting the importance of studying them for inclusion in a P. vivax antimalarial vaccine.
A Human Cellular Model for Colorectal Anastomotic Repair: The Effect of Localization and Transforming Growth Factor-β1 Treatment on Collagen Deposition and Biomarkers
Authors: Türlü Ceylan , Willumsen Nicholas , Marando Debora , Schjerling Peter , Biskup Edyta , Hannibal Jens , Jorgensen Lars N. , Ågren Magnus S.
Published: February 2021

Anastomotic leakage (AL) is a devastating complication after colorectal surgery, possibly due to the loss of stabilizing collagen fibers in the submucosa. Our aim was to assess the formation of collagen in the colon versus the rectum with or without transforming growth factor (TGF)-β1 exposure in a human cellular model of colorectal repair. Primary fibroblasts were isolated by an explant procedure from clinically resected tissue rings during anastomosis construction in 19 consecutive colorectal patients who underwent laparoscopy. The cells, identified as fibroblasts by morphologic characteristics and flow cytometry analysis (CD90+), were cultured for 8 days and in 12 patients in the presence of 1 ng/mL TGF-β1. Total collagen deposition was measured colorimetrically after Sirius red staining of fixed cell layers, and type I, III, and VI collagen biosynthesis and degradation were specifically determined by the biomarkers PINP, PRO-C3, PRO-C6, and C3M in conditioned media by competitive enzyme-linked immunosorbent assays. Total collagen deposition by fibroblasts from the colon and rectum did not significantly differ. TGF-β1 treatment increased PINP, PRO-C6, and total collagen deposition. Mechanistically, TGF-β1 treatment increased COL1A1 and ACTA2 (encoding α-smooth muscle actin), and decreased COL6A1 and MMP2 mRNA levels in colorectal fibroblasts. In conclusion, we found no effect of anatomic localization on collagen production by fibroblasts derived from the large intestine. TGF-β1 represents a potential therapeutic agent for the prevention of AL by increasing type I collagen synthesis and collagen deposition.
Effects of Meal Fructose/Glucose Composition on Postprandial Glucose Appearance and Hepatic Glycogen Synthesis in Healthy Subjects
Authors: Barosa Cristina , Ribeiro Rogério T. , Andrade Rita , Raposo João F. , Jones John G.
Published: February 2021

Dietary fructose overshadows glucose in promoting metabolic complications. Intestinal fructose metabolism (IFM) protects against these effects in rodents, by favoring gluconeogenesis, but the extent of IFM in humans is not known. We therefore aimed to infer the extent of IFM by comparing the contribution of dietary fructose to systemic glucose and hepatic glycogen appearance postprandially. Twelve fasting healthy subjects ingested two protein meals in random order, one supplemented with 50 g 5/95 fructose/glucose (LF) and the other with 50 g 55/45 fructose/glucose (HF). Sources of postprandial plasma glucose appearance and hepatic glycogen synthesis were determined with deuterated water. Plasma glucose excursions, as well as pre- and post-meal insulin, c-peptide, and triglyceride levels were nearly identical for both meals. The total gluconeogenic contribution to plasma glucose appearance was significantly higher for HF versus LF (65 ± 2% vs. 34 ± 3%, p < 0.001). For HF, Krebs cycle anaplerosis accounted for two-thirds of total gluconeogenesis (43 ± 2%) with one-third from Triose-P sources (22 ± 1%). With LF, three-quarters of the total gluconeogenic contribution originated via Krebs cycle anaplerosis (26 ± 2%) with one-quarter from Triose-P sources (9 ± 2%). HF and LF gave similar direct and indirect pathway contributions to hepatic glycogen synthesis. Increasing the fructose/glucose ratio had significant effects on glucose appearance sources but no effects on hepatic glycogen synthesis sources, consistent with extensive IFM. The majority of fructose carbons were converted to glucose via the Krebs cycle.
Peroral Cholangioscopy-Guided Forceps Mapping Biopsy for Evaluation of the Lateral Extension of Biliary Tract Cancer
Authors: Onoyama Takumi , Hamamoto Wataru , Sakamoto Yuri , Kawahara Shiho , Yamashita Taro , Koda Hiroki , Kawata Soichiro , Takeda Yohei , Matsumoto Kazuya , Isomoto Hajime
Published: February 2021

Background: Peroral cholangioscopy (POCS)-guided forceps mapping biopsy (FMB) is a method for the accurate preoperative identification of the extent of the disease of biliary tract cancer (BTC). However, the diagnostic value of POCS-FMB is still uncertain. Objectives: We evaluated the diagnostic utility of POCS-FMB for the identification of lateral extension—superficial intraductal spread longitudinally and continuously from the main lesion—of BTC. Methods: In the retrospective study, patients who received POCS-FMB and surgery for curative resection of BTC between September 2016 and August 2019 at our medical institution were enrolled. The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was evaluated. Furthermore, we also evaluated the factors affecting the diagnostic accuracy of POCS-FMB. Results: A total of 23 patients with BTC were enrolled, and 24 procedures of POCS-FMB from 96 sites of biliary tracts were performed. The sensitivity, specificity, and accuracy of POCS-FMB were 53.8%, 63.9%, and 63.1%, respectively. In the multivariate logistic regression analyses, the biopsy from the bifurcation of biliary tracts was a significant factor affecting the diagnostic accuracy of POCS-FMB (odds ratio 3.538, 95%; confidence interval 1.151–10.875, p = 0.027). Conclusions: The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was insufficient. The biopsy from the bifurcation of biliary tracts was a positive factor affecting the diagnostic accuracy of POCS-FMB.
Taking Implementation Seriously in the Evaluation of Urban Growth Management Strategies: “Safeguarding the Future” of the Antwerp City-Region
Authors: de Olde Clemens , Oosterlynck Stijn
Published: February 2021

Contemporary evaluations of urban growth management (UGM) strategies often take the shape of quantitative measurements of land values and housing prices. In this paper, we argue that it is of key importance that these evaluations also analyse the policy formulation and implementation phases of growth management strategies. It is in these phases that the institutions and discourses are (trans)formed in which UGM strategies are embedded. This will enable us to better understand the conditions for growth management policies’ success or failure. We illustrate this point empirically with the case of demarcating urban areas in the region of Flanders, Belgium. Using the Policy Arrangement Approach, the institutional dynamics and discursive meanings in this growth instrument’s formulation and implementation phase are unravelled. More specifically, we explain how the Flemish strategic spatial planning vision of restraining sprawl was transformed into one of accommodating growth in the demarcation of the Antwerp Metropolitan Area, epitomised by two different meanings of the phrase “safeguarding the future.” In conclusion, we argue that, in Antwerp, the demarcation never solidified into a stable policy arrangement, rendering it largely ineffective. We end by formulating three recommendations to contribute to future attempts at managing urban growth in Flanders.
Modeling and Simulation of Dissemination of Cultivated Land Protection Policies in China
Authors: Lu Xinhai , Zhang Yanwei , Tang Handong
Published: February 2021

Cultivated land protection is the top priority of the national economy in China and the livelihood of people. Cultivated land protection policies (CLPP) play an important role in the protection of cultivated land. However, the process of dissemination of CLPP on social networks of farmers has problems, such as distortion of policy content, single dissemination channels, low level of farmers’ knowledge, and low dissemination efficiency. For revealing the characteristics of the dissemination of CLPP in the farmers’ social networks (FSN), this study combines the Suspected–Exposed–Infected–Recovered–Suspected (SEIRS) epidemic model to construct a model of CLPP dissemination suitable for FSN. In addition, a numerical simulation of the dissemination process of CLPP is conducted on the FSN, and the influence of the structural characteristics of the FSN and different model parameters on the dissemination of CLPP is analyzed. Results show that (1) the dissemination rate between farmers in FSN has a significant impact on the scale and speed of CLPP. A greater initial dissemination rate corresponds to faster speed and larger scale of CLPP dissemination. (2) A greater node degree in FSN means stronger dissemination ability for CLPP. Therefore, identifying structural holes (opinion leaders) in FSN can effectively promote the dissemination of CLPP. (3) The SEIRS model can dynamically describe the evolution law of CLPP dissemination process over time through the four states of farmer nodes of suspected, exposed, infected, and recovered. Numerical simulation results show that the immune degradation rate is proportional to CLPP. However, the direct immunization rate is inversely proportional. The increase in immune degradation rate can reduce the number of recovered farmers and improve the efficiency of CLPP dissemination. On the basis of the abovementioned conclusions, this study draws policy recommendations to increase the scale and speed of CLPP dissemination in China.
Tetramethyl 1,1′-(2-[{4,5-bis(Methoxycarbonyl)-1H-1,2,3-triazol-1-yl}methyl]-2-[(4-methylphenyl)sulfonamido]propane-1,3-diyl)bis(1H-1,2,3-triazole-4,5-dicarboxylate)
Authors: Fall Serigne Abdou Khadir , Hajib Sara , Karai Oumaima , Aouine Younas , Boukhssas Salaheddine , Faraj Hassane , Alami Anouar
Published: January 2021

A new compound tetramethyl 1,1′-(2-[{4,5-bis(methoxycarbonyl)-1H-1,2,3-triazol-1-yl}methyl]-2-[(4-methylphenyl)sulfonamido]propane-1,3-diyl)bis(1H-1,2,3-triazole-4,5-dicarboxylate) (3) was prepared in two steps starting from 2-((4-methylphenyl)sulfonamido)-2-((tosyloxy)methyl)propane-1,3-diylbis(4-methylbenzenesulfonate) (1), with an overall yield of 74%. The key step being the copper-free Huisgen cycloaddition between N-(1,3-diazido-2-(azidomethyl)propan-2-yl)-4-methylbenzenesulfonamide (2) and commercially available dimethyl acetylenedicarboxylate. The chemical structure of compound 3 was determined by IR, 1D and 2D NMR experiments, and elemental analysis.
Color and Translucency Stability of Three-Dimensional Printable Dental Materials for Crown and Bridge Restorations
Authors: Kim Jong-Eun , Choi Won-Huy , Lee Dasun , Shin Yooseok , Park Sung-Ho , Roh Byoung-Duck , Kim Dohyun
Published: January 2021

The purpose of this study was to examine and compare color and translucency stability of three-dimensional (3D) printable dental materials for crown and bridge restorations. Five different materials were investigated, and twelve disc-shaped specimens of two different thicknesses (1 and 2 mm) were prepared using a digital light processing 3D printer. Color measurements were made according to the CIELAB color scale (L*, a*, and b*) using a spectrophotometer 1 h, 1 day, 1 week, one month, and six months after post-curing of the materials, and the translucency parameter (TP) was calculated. The L*, a*, b*, and TP values were compared among the different materials and storage periods using repeated measures analysis of variance. Color and translucency changes of the specimens after the different storage periods were compared with 1 h measurements to determine whether they exceeded clinically perceivable thresholds. The L*, a*, b*, and TP values showed significant differences according to the storage periods, as well as among the materials. Until one month, some materials demonstrated distinct color differences, while others showed small color differences below a clinically perceivable threshold. The translucency differences were not clinically perceivable for any specimen. After six months, all specimens demonstrated large color changes, whereas the changes in translucency were relatively small. In conclusion, the color of 3D printable dental materials changed with time, and the differences varied with the materials used. On the contrary, the changes in translucency were small. Overall, the materials became darker, more yellowish, and more opaque after six months of water storage.
Tribological Behavior of Phenolic Resin-Based Friction Composites Filled with Graphite
Authors: Zhang En , Gao Fei , Fu Rong , Lu Yunzhuo , Han Xiaoming , Su Linlin
Published: February 2021

In this paper, the influence of graphite (Gr) on the dry sliding tribological properties of phenolic resin (PF) composites was studied under different sliding speeds of 3.1–47.1 m/s. The wear mechanism was investigated by the observation of the morphology of the transfer layer during the dry sliding process. It was found that the addition of Gr could decrease the friction coefficient and wear rate effectively, and the friction coefficient and wear rate decreased with the increase of Gr content in the range of 10–30 vol.%. The dominant wear mechanisms of PF-based friction composites changed from adhesive wear to fatigue wear (in the form of peeling-off) in the high sliding speed condition after the addition of Gr. The addition of Gr effectively reduced the sensitivity of PF-based friction materials to sliding speeds, and thus enhanced the stability of the friction coefficient. When the content of Gr was above 20 vol.%, the stability of the friction coefficient was relatively steady.
Linking the Electrical Conductivity and Non-Stoichiometry of Thin Film Ce1−xZrxO2−δ by a Resonant Nanobalance Approach
Authors: Kogut Iurii , Wollbrink Alexander , Steiner Carsten , Wulfmeier Hendrik , El Azzouzi Fatima-Ezzahrae , Moos Ralf , Fritze Holger
Published: February 2021

Bulk ceria-zirconia solid solutions (Ce1−xZrxO2−δ, CZO) are highly suited for application as oxygen storage materials in automotive three-way catalytic converters (TWC) due to the high levels of achievable oxygen non-stoichiometry δ. In thin film CZO, the oxygen storage properties are expected to be further enhanced. The present study addresses this aspect. CZO thin films with 0 ≤ x ≤ 1 were investigated. A unique nano-thermogravimetric method for thin films that is based on the resonant nanobalance approach for high-temperature characterization of oxygen non-stoichiometry in CZO was implemented. The high-temperature electrical conductivity and the non-stoichiometry δ of CZO were measured under oxygen partial pressures pO2 in the range of 10−24–0.2 bar. Markedly enhanced reducibility and electronic conductivity of CeO2-ZrO2 as compared to CeO2−δ and ZrO2 were observed. A comparison of temperature- and pO2-dependences of the non-stoichiometry of thin films with literature data for bulk Ce1−xZrxO2−δ shows enhanced reducibility in the former. The maximum conductivity was found for Ce0.8Zr0.2O2−δ, whereas Ce0.5Zr0.5O2-δ showed the highest non-stoichiometry, yielding δ = 0.16 at 900 °C and pO2 of 10−14 bar. The defect interactions in Ce1−xZrxO2−δ are analyzed in the framework of defect models for ceria and zirconia.
Enhanced Thermal Conductivity of Polyamide-Based Nanocomposites Containing Graphene Oxide Sheets Decorated with Compatible Polymer Brushes
Authors: Łątka Łukasz , Goc Kamil , Kapusta Czesław , Zapotoczny Szczepan
Published: February 2021

Polyamide-based nanocomposites containing graphene platelets decorated with poly(acrylamide) brushes were prepared and characterized. The brushes were grafted from the surface of graphene oxide (GO), a thermally conductive additive, using atom transfer radical polymerization, which led to the formation of the platelets coated with covalently tethered polymer layers (GO_PAAM), accounting for ca. 31% of the total mass. Polyamide-6 (PA6) nanocomposites containing 1% of GO_PAAM were formed by extrusion followed by injection molding. The thermal conductivity of the nanocomposite was 54% higher than that of PA6 even for such a low content of GO. The result was assigned to strong interfacial interactions between the brushes and PA6 matrix related to hydrogen bonding. Control nanocomposites containing similarly prepared GO decorated with other polymer brushes that are not able to form hydrogen bonds with PA6 revealed no enhancement of the conductivity. Importantly, the nanocomposite containing GO_PAAM also demonstrated larger tensile strength without deteriorating the elongation at break value, which was significantly decreased for the other coated platelets. The proposed approach enhances the interfacial interactions thanks to the covalent tethering of dense polymer brushes on 2D fillers and may be used to improve thermal properties of other polymer-based nanocomposites with simultaneous enhancement of their mechanical properties.
Mechanical Properties of Hardened 3D Printed Concretes and Mortars—Development of a Consistent Experimental Characterization Strategy
Authors: Meurer Maximilian , Classen Martin
Published: February 2021

Today, it is already foreseeable that additive manufacturing of mortar and concrete has groundbreaking potential and will revolutionize or at least fundamentally change the way we build. In recent years, 3D concrete printing (3DCP) with extrusion-based deposition methods has been pushed forward by a growing research community. Albeit being regarded one of the most promising innovations in construction industry, a consistent characterization methodology for assessing the constitutive behavior of 3D printed, hardened cementitious materials is missing, so far, which hinders its widespread use in engineering practice. The major objective of this paper is to fill this gap by developing a new experimental framework that can thoroughly describe the mechanical properties of 3D printed cementitious materials. Based on both a review of state-of-the-art test setups and a comprehensive experimental campaign, the present paper proposes a set of easy-to-use experimental methods that allow us to assess flexural, tensile, shear and compressive strength as well as fracture energy of 3D printed concretes and mortars in a reliable and reproducible manner. The experimental results revealed anisotropic material behavior for flexural, tensile, shear and compressive loading. Furthermore, they confirm that interval time (time gap between deposition of subsequent layers) has a crucial effect on investigated material properties leading to a severe reduction in strength and fracture energy for longer interval times.
A Design Method for a Variable Combined Brake System for Motorcycles Applying the Adaptive Control Method
Authors: Lin Yuan-Ting , Tseng Chyuan-Yow , Kuang Jao-Hwa , Hwang Yeong-Maw
Published: February 2021

The variable combined brake system (VCBS) is a mechanism for motorcycles to simultaneously activate the front and rear brake systems by using one brake lever or pedal. The purpose is to reduce the risk of rollover accidents due to misuse of the front brake when panic braking. Due to its ability in a wide variation range of braking force distribution (BFD) ratios between the front and rear wheels, the VCBS can simultaneously achieve high braking effort and driving comfort performances, provided that the BFD ratio is designed appropriately. This paper aimed to develop the design method for the VCBS. A mathematical model of the VCBS mechanism is derived, and a parameter matching design method that applies adaptive control theory is proposed. A prototype of VCBS is designed and built based on the proposed method. The straight-line braking test results show that the motorcycle equipped with the VCBS prototype effectively obtained a high braking performance in deceleration. The obtained maximum deceleration is an average of 6.37 m/s2 (0.65 g) under an average handbrake lever force of 154.29 N. For front brake failure, maximum deceleration is obtained at an average of 3.38 m/s2 (0.34 g), which is higher than the homologation requirement of 2.9 m/s2.
Nonlinear Spectrum and Fixed Point Index for a Class of Decomposable Operators
Authors: Kang Shugui , Zhang Yanlei , Feng Wenying
Published: January 2021

We study a class of nonlinear operators that can be written as the composition of a linear operator and a nonlinear map. We obtain results on fixed point index based on parameters that are related to the definitions of nonlinear spectra. As a particular case, existence of positive solutions for a second-order differential equation with separated boundary conditions is proved. The result also provides a spectral interval for the corresponding Hammerstein integral operator.
The Lie Algebraic Approach for Determining Pricing for Trade Account Options
Authors: Tseng Shih-Hsien , Nguyen Tien Son , Wang Ruei-Ci
Published: January 2021

In recent years, many advanced techniques have been applied to financial problems; however, very few scholars have used the Lie theory. The purpose of this study was to examine the options for a trade account through Lie symmetry analysis. According to our results, it is effective for determining analytical solutions for pricing issues and solving other partial differential equations. The proposed solution can be used by further researchers or practitioners in option pricing problems for better performance compared with the classical Black–Scholes model.
A Clustering Perspective of the Collatz Conjecture
Authors: Machado José A. Tenreiro , Galhano Alexandra , Cao Labora Daniel
Published: February 2021

This manuscript focuses on one of the most famous open problems in mathematics, namely the Collatz conjecture. The first part of the paper is devoted to describe the problem, providing a historical introduction to it, as well as giving some intuitive arguments of why is it hard from the mathematical point of view. The second part is dedicated to the visualization of behaviors of the Collatz iteration function and the analysis of the results.
Fucoxanthin@Polyvinylpyrrolidone Nanoparticles Promoted Oxidative Stress-Induced Cell Death in Caco-2 Human Colon Cancer Cells
Authors: Sui Yue , Gu Yue , Lu Yujing , Yu Chenxu , Zheng Jie , Qi Hang
Published: February 2021

Fucoxanthin (FX), a natural carotenoid found in seaweed with multiple functional activities, is unstable with a poor water solubility that limits its utilization. This study aimed to improve FX’s stability and bioavailability via the nano-encapsulation of FX in polyvinylpyrrolidone (PVP)-coated FX@PVP nanoparticles (NPs). The FX@PVP NPs were evaluated in terms of their morphology, stability, encapsulation efficiency (EE), loading capacity (LC), and in vitro release to optimize the encapsulation parameters, and a 1:8 FX:PVP ratio was found to perform the best with the highest EE (85.50 ± 0.19%) and LC (10.68 ± 0.15%) and improved FX stability. In addition, the FX@PVP NPs were shown to effectively deliver FX into Caco-2 cancer cells, and the accumulation of FX in these cancer cells showed pro-oxidative activities to ameliorate H2O2-induced damage and cell death. The FX@PVP NPs could potentially become a new therapeutical approach for targeted cancer treatment.
State-of-the-Art Water Treatment in Czech Power Sector: Industry-Proven Case Studies Showing Economic and Technical Benefits of Membrane and Other Novel Technologies for Each Particular Water Cycle
Authors: Marek Jaromír
Published: January 2021

The article first summarizes case studies on the three basic types of treated water used in power plants and heating stations. Its main focus is Czechia as the representative of Eastern European countries. Water as the working medium in the power industry presents the three most common cycles—the first is make-up water for boilers, the second is cooling water and the third is represented by a specific type of water (e.g., liquid waste mixtures, primary and secondary circuits in nuclear power plants, turbine condensate, etc.). The water treatment technologies can be summarized into four main groups—(1) filtration (coagulation) and dosing chemicals, (2) ion exchange technology, (3) membrane processes and (4) a combination of the last two. The article shows the ideal industry-proven technology for each water cycle. Case studies revealed the economic, technical and environmental advantages/disadvantages of each technology. The percentage of technologies operated in energetics in Eastern Europe is briefly described. Although the work is conceived as an overview of water treatment in real operation, its novelty lies in a technological model of the treatment of turbine condensate, recycling of the cooling tower blowdown plus other liquid waste mixtures, and the rejection of colloidal substances from the secondary circuit in nuclear power plants. This is followed by an evaluation of the potential novel technologies and novel materials.
Thermodynamic Behavior of Fe-Mn and Fe-Mn-Ag Powder Mixtures during Selective Laser Melting
Authors: Kraner Jakob , Medved Jožef , Godec Matjaž , Paulin Irena
Published: January 2021

Additive manufacturing is a form of powder metallurgy, which means the properties of the initial metal powders (chemical composition, powder morphology and size) impact the final properties of the resulting parts. A complete characterization, including thermodynamic effects and the behavior of the metal powders at elevated temperatures, is crucial when planning the manufacturing process. The analysis of the Fe-Mn and Fe-Mn-Ag powder mixtures, made from pure elemental powders, shows a high susceptibility to sintering in the temperature interval from 700 to 1000 °C. Here, numerous changes to the manganese oxides and the αMn to βMn transformation occurred. The problems of mechanically mixed powders, when using selective laser melting, were highlighted by the low flowability, which led to a less controllable process, an uncontrolled arrangement of the powder and a large percentage of burnt manganese. All this was determined from the altered chemical compositions of the produced parts. The impact of the increased manganese content on the decreased probability of the transformation from γ-austenite to ε-martensite was confirmed. The ε-martensite in the microstructure increased the hardness of the material, but at the same time, its magnetic properties reduce the usefulness for medical applications. However, the produced parts had comparable elongations to human bone.
Influence of the Cooling Time on the Microstructural Evolution and Mechanical Performance of a Double Pulse Resistance Spot Welded Medium-Mn Steel
Authors: Stadler Manfred , Schnitzer Ronald , Gruber Martin , Steineder Katharina , Hofer Christina
Published: February 2021

In the present work, the influence of the cooling time on the mechanical performance, hardness, and microstructural features of a double pulse resistance spot welded medium-Mn steel are investigated. Curves of the electrical resistance throughout the welding revealed that the cooling time strongly influences the heat generation during the second pulse. A second pulse after a short cooling time re-melts the center, and heat treats the edge of the primary fusion zone. This desired in-process heat treatment leads to a modification of the cast-like martensitic structure by recrystallization illustrated by electron backscatter diffraction measurements and to a homogenization of manganese segregations, visualized by energy-dispersive X-ray spectroscopy, which results in an enhanced mechanical performance during the cross tension strength test. In contrast, during excessively long cooling times, the resistance drops to a level where the heat generation due to the second pulse is too low to sufficiently re-heat the edge of the primary FZ. As a consequence, the signs of recrystallization disappear, and the manganese segregations are still present at the edge of the fusion zone, which leads to a deterioration of the mechanical properties.
Production and Properties of High Entropy Carbide Based Hardmetals
Authors: Pötschke Johannes , Dahal Manisha , Vornberger Anne , Herrmann Mathias , Michaelis Alexander
Published: February 2021

Dense, high-entropy carbide cobalt-bonded hardmetals with two different compositions, namely (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co and (Ta-Ti-Nb-V-W)C-19.2 vol% Co, were successfully manufactured by gas pressure sintering (SinterHIP) at 1400 °C and 100 bar Ar pressure. The microstructure of these hardmetals consists of a rigid skeletal carbide phase embedded in a tough Co binder phase. EDS mappings showed that the high-entropy carbide phase did not decompose and that a typical hardmetal microstructure was realized. Only in the case of the (Hf-Ta-Ti-Nb-V)C-Co hardmetal was some undissolved TaC and HfO2, as well as some clustered vanadium titanium carbide phase, found, resulting in a split-up of the HEC phase into two very similar HEC phases. This resulted in a reduced hardness to fracture toughness ratio for this composition. Measurements of magnetic saturation polarization showed values between 57.5% and 70% of theoretical magnetic saturation polarization, indicating marginal dissolution of the carbide-forming metal elements in the binder phase. The hardness value HV10 for (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co was 1203 HV10 and 1432 HV10 for (Ta-Ti-Nb-V-W)C-19.2 vol% Co.
Characterization of Precipitation in 7055 Aluminum Alloy by Laser Ultrasonics
Authors: Zhu Zhenge , Peng Hao , Xu Yacheng , Song Xueyong , Zuo Jinrong , Wang Ying , Shu Xuedao , Yin Anmin
Published: February 2021

After different rolling conditions, four 7055 aluminum alloy samples with different precipitation sizes were measured by scanning electron microscope, transmission electron microscope and laser ultrasonic. The attenuation coefficients of ultrasound measured by laser ultrasonic were calculated in the time domain, frequency domain and wavelet denoising, respectively. The relationship between the precipitate size and attenuation coefficient was established. The results show that the attenuation of the ultrasonic wave is related to the size of the precipitated phase; this provides a new method for rapid non-destructive testing of the precipitation of aluminum alloys.