bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the Binary MgO/SiO2 Mixed Oxide Catalysts for the Conversion of Ethanol to 1,3-Butadiene
Authors: Reschetilowski Wladimir , Hauser Matthias , Alscher Felix , Klauck Mandy , Kalies Grit
Published: August 2020

The demand for 1,3-butadiene, one of the most important raw materials in the rubber industry, is constantly increasing. The Lebedev process is a classical method of producing 1,3-butadiene from ethanol, which is to be optimized with regard to the mixed oxide catalysts used. In this work, the binary MgO/SiO2 solid system was tested with regard to its optimum chemical composition for the catalytic conversion of ethanol to 1,3-butadiene. Furthermore, novel mesoporous mixed oxides were prepared to investigate their textural, structural, and surface chemical properties as well as the catalytic activity. Nitrogen physisorption, scanning electron microscopy (SEM), and temperature-programmed ammonia desorption (NH3-TPD) measurements were carried out and evaluated. It was shown that the optimum yield of 1,3-butadiene is achieved by using MgO/SiO2 mixed oxide catalysts with 85–95 mol% MgO and not, as suggested by Lebedev, with 75 mol% MgO. The NH3-TPD measurements revealed that the maximum acid-site density is achieved with an equimolar up to magnesium-rich composition. During the synthesis of binary MgO/SiO2 solid systems based on mesoporous MgO, a thermally stable and ordered structure was formed in the autoclave, depending on the carbonate used and on the duration of the treatment.
Effect of Ag-Addition on the Catalytic and Physicochemical Properties of Ni/ZrO2 Catalyst in Oxy-Steam Reforming of CH4 and LNG Processes
Authors: Mosinska Magdalena , Stepinska Natalia , Chalupka Karolina , Maniukiewicz Waldemar , Szynkowska Malgorzata I. , Mierczynski Pawel
Published: August 2020

This work presents, for the first time, the catalytic studies of bimetallic Ag-Ni catalysts in the oxy-steam reforming (OSR) of liquefied natural gas (LNG) to hydrogen generation. The physicochemical properties of monometallic Ni and bimetallic catalysts were investigated using various techniques, such as: BET, TPR-H2, TPD-NH3, XRD, TG and SEM-EDS. The catalytic studies showed that the promotion of 20% Ni/ZrO2 catalyst by silver (by 1 or 2 wt.%) improves the efficiency of the produced hydrogen in the oxy-steam reforming of LNG at high temperature. The promotional effect of silver on the reducibility of a Ni/ZrO2 catalyst has been proven. The interactions between Ag and Ni have been proven, and explain the catalytic activity of the catalysts in the investigated processes. TG-DTA-MS results obtained for the spent catalysts proved that the small addition of silver to monometallic nickel catalyst reduces the amount of the carbon deposit formed on the catalyst surface during the oxy-steam reforming of LNG process. Obtained results in this work confirmed that liquid natural gas processing may become an alternative to fossil fuels and confirmed the validity of the hydrogen production via oxy-steam reforming of LNG.
Catalytic Hydrogen Production from Methane: A Review on Recent Progress and Prospect
Authors: Chen Luning , Qi Zhiyuan , Zhang Shuchen , Su Ji , Somorjai Gabor A.
Published: August 2020

Natural gas (Methane) is currently the primary source of catalytic hydrogen production, accounting for three quarters of the annual global dedicated hydrogen production (about 70 M tons). Steam–methane reforming (SMR) is the currently used industrial process for hydrogen production. However, the SMR process suffers with insufficient catalytic activity, low long-term stability, and excessive energy input, mostly due to the handling of large amount of CO2 coproduced. With the demand for anticipated hydrogen production to reach 122.5 M tons in 2024, novel and upgraded catalytic processes are desired for more effective utilization of precious natural resources. In this review, we summarized the major descriptors of catalyst and reaction engineering of the SMR process and compared the SMR process with its derivative technologies, such as dry reforming with CO2 (DRM), partial oxidation with O2, autothermal reforming with H2O and O2. Finally, we discussed the new progresses of methane conversion: direct decomposition to hydrogen and solid carbon and selective oxidation in mild conditions to hydrogen containing liquid organics (i.e., methanol, formic acid, and acetic acid), which serve as alternative hydrogen carriers. We hope this review will help to achieve a whole picture of catalytic hydrogen production from methane.
Effect of Sb-Doped SnO2 Nanostructures on Electrocatalytic Performance of a Pt Catalyst for Methanol Oxidation Reaction
Authors: Lee Seul-Gi , Han Sang-Beom , Lee Woo-Jun , Park Kyung-Won
Published: August 2020

In this study, antimony-doped tin oxide (ATO) support materials for a Pt anode catalyst in direct methanol fuel cells were prepared and electrochemically evaluated. When the heating temperature was increased from 300 to 400 °C, the ATO samples exhibited a slightly decreased specific surface area and increased electrical conductivity. In particular, the ATO sample heated at 350 °C in an air atmosphere showed improved electrical conductivity (1.3 S cm−1) with an optimum specific surface area of ~34 m2 g−1. The supported Pt catalysts were synthesized using a polyol process with as-prepared and heated ATO samples and Vulcan XC-72R as supports (denoted as Pt/ATO, Pt/ATO-350, and Pt/C, respectively). In the methanol oxidation reaction (MOR), compared to Pt/C and Pt/ATO, Pt/ATO-350 exhibited the best electrocatalytic activity and stability for MOR, which could be attributed to Pt nanoparticles on the relatively stable oxide support with high electrical conductivity and interaction between the Pt catalyst and the heated ATO support.
CuAlCe Oxides Issued from Layered Double Hydroxide Precursors for Ethanol and Toluene Total Oxidation
Authors: Dib Hadi , El Khawaja Rebecca , Rochard Guillaume , Poupin Christophe , Siffert Stéphane , Cousin Renaud
Published: August 2020

CuAlCe oxides were obtained from hydrotalcite-type precursors by coprecipitation using a M2+/M3+ ratio of 3. The collapse of the layered double hydroxide structure following the thermal treatment leads to the formation of mixed oxides (CuO and CeO2). The catalytic performance of the copper-based catalysts was evaluated in the total oxidation of two Volatile Organic Compounds (VOCs): ethanol and toluene. XRD, SEM Energy-Dispersive X-ray Spectrometry (EDX), H2-temperature programmed reduction (TPR) and XPS were used to characterize the physicochemical properties of the catalysts. A beneficial effect of combining cerium with CuAl-O oxides in terms of redox properties and the abatement of the mentioned VOCs was demonstrated. The sample with the highest content of Ce showed the best catalytic properties, which were mainly related to the improvement of the reducibility of the copper species and their good dispersion on the surface. The presence of a synergetic effect between the copper and cerium elements was also highlighted.
Saffron Crudes and Compounds Restrict MACC1-Dependent Cell Proliferation and Migration of Colorectal Cancer Cells
Authors: Güllü Nazli , Kobelt Dennis , Brim Hassan , Rahman Shaman , Timm Lena , Smith Janice , Soleimani Akbar , Di Marco Stefano , Bisti Silvia , Ashktorab Hassan , Stein Ulrike
Published: August 2020

The high mortality rate of colorectal cancer (CRC) patients is directly associated with metastatic dissemination. However, therapeutic options specifically for metastasis are still limited. We previously identified Metastasis-Associated in Colon Cancer 1 (MACC1) as a major causal metastasis-inducing gene. Numerous studies confirmed its value as a biomarker for metastasis risk. We investigated the inhibitory impact of saffron on MACC1-induced cancer cell growth and motility. Saffron crudes restricted the proliferation and migration of MACC1-expressing CRC cells in a concentration- and MACC1-dependent manner. Saffron delays cell cycle progression at G2/M-phase and does not induce apoptosis. Rescue experiments showed that these effects are reversible. Analysis of active saffron compounds elucidated that crocin was the main compound that reproduced total saffron crudes effects. We showed the interaction of MACC1 with the cancer stem cell (CSC) marker DCLK1, which contributes to metastasis formation in different tumor entities. Saffron extracts reduced DCLK1 with crocin being responsible for this reduction. Saffron’s anti-proliferative and anti-migratory effects in MACC1-expressing cells are mediated by crocin through DCLK1 down-regulation. This research is the first identification of saffron-based compounds restricting cancer cell proliferation and motility progression via the novel target MACC1.
Opto-Electronic Nose Coupled to a Silicon Micro Pre-Concentrator Device for Selective Sensing of Flavored Waters
Authors: Slimani Sami , Bultel Etienne , Cubizolle Thomas , Herrier Cyril , Rousselle Tristan , Livache Thierry
Published: August 2020

Headspace analysis of highly humid samples remains a challenge for artificial olfaction. Based on surface plasmon resonance imaging and bio-based sensors, the NeOse Pro olfactive analyzer yields multivariate data and enhances the statistical discrimination capacity of odor patterns. However, the presence of a high background signal, such as water vapor from aqueous samples, may deteriorate its discriminant ability. Recently, miniaturized pre-concentrators packed with hydrophobic adsorbent have been developed to improve the detection limit of gas analysis methods and to enhance their selectivity by reducing the water’s background signal. This work presents, for the first time, the coupling of a miniaturized silicon micro pre-concentration unit (µPC) to a bio-based opto-electronic nose (NeOse Pro). The results showed that the coupling of a silicon µPC with the NeOse Pro led to an improvement in the detection limit of n-nonane by at least a factor of 125. Additionally, principal component analysis (PCA) of eight different flavored waters showed an enhanced discrimination ability of the coupled set-up in highly humid conditions.
Defining a “Good Death” in Pediatric Oncology: A Mixed Methods Study of Healthcare Providers
Authors: Taylor Mallory R. , Barton Krysta S. , Kingsley Jenny M. , Heunis Julia , Rosenberg Abby R.
Published: August 2020

Delivering optimal end-of-life (EOL) care to children and adolescents is a healthcare priority, yet relatively little is known about what patients, families, and healthcare providers (HCPs) consider “best” practices. The objective of this study was to identify factors that pediatric oncology HCPs consider important for EOL care. This was a cross-sectional mixed methods study. Participants were multidisciplinary pediatric oncology staff who completed surveys and participated in semi-structured qualitative interviews. Interviews were analyzed using a modified grounded theory approach. Provider statements were compared based on years of experience (≤10 or >10 years) and discipline (non-physician or physician). A total of n = 19 staff (74% female) enrolled, including physicians (n = 8), advanced practice providers (n = 4), nurses (n = 2), music/art therapists (n = 2), physical therapists (n = 1), educators (n = 1), and chaplains (n = 1). Most HCPs identified communication, symptom control, and acceptance as features of a “good” death. Compared to physicians, non-physicians focused on relationships (67% vs. 33%, p = 0.007); HCPs with ≤10 years of experience (n = 11) more frequently identified the benefits of a multidisciplinary team (74% vs. 26%, p = 0.004). This study identified many common HCP-defined components of “good” pediatric EOL care in addition to some differing perspectives depending on discipline and experience. Incorporating diverse HCP perspectives with those of the patient and family can guide contemporary high-quality pediatric EOL clinical care and education.
Directly-Patternable Bi2O3 Nanoparticle for Polymer Nanocomposite Capacitor
Authors: Son Ki-Hoon , Lee Hong-Sub
Published: August 2020

A polyvinylidene fluoride (PVDF) film incorporating size-controlled, uniformly dispersed, directly patterned Bi2O3 nanoparticles was developed to achieve a high-k polymer nanocomposite capacitor. The photochemical metal-organic deposition (PMOD) method was employed to form uniformly dispersed and directly patterned nanoparticles on the substrate. Bi nanoparticles were produced by spin coating a Bismuth 2-ethylhexanoate solution on a Pt substrate with UV irradiation for 1, 4, 7, and 10 min. The average diameter of nanoparticles and the number of nanoparticles per unit area (μm2) were about 30, 70, and 120 nm and 30, 30, and 31 particles/μm2 for UV irradiation times of 4, 7, and 10 min, respectively. In addition, the capacitance of PVDF nanocomposite film could be controlled by the Bi2O3 nanoparticle size. The PVDF nanocomposite film containing Bi2O3 nanoparticles with 1, 4, 7, and 10 min UV irradiation were able to improve capacitance by about 1.4, 2.0, 2.7, and 3.4 times compared with an as-prepared PVDF film. By using a mask aligner, directly pattered Bi nanoparticles on the substrate, which had a 5 μm line width pattern, were successfully defined and demonstrated.
Nanowire Aptamer-Sensitized Biosensor Chips with Gas Plasma-Treated Surface for the Detection of Hepatitis C Virus Core Antigen
Authors: Malsagova Kristina A. , Pleshakova Tatyana O. , Galiullin Rafael A. , Shumov Ivan D. , Kozlov Andrey F. , Romanova Tatyana S. , Popov Vladimir P. , Glukhov Alexander V. , Konev Vladimir A. , Archakov Alexander I. , Ivanov Yuri D.
Published: August 2020

Herein, we have demonstrated highly sensitive real-time biospecific detection of a protein marker of hepatitis C—the core antigen of hepatitis C virus (HCVcoreAg)—using a nanowire (NW) biosensor. The primary element of the NW-biosensor is a chip with p-type conductance, bearing silicon-on-insulator (SOI) nanowire structures on its surface. The nanowire structures are fabricated by gas-plasma treatment and electron beam lithography. The detection specificity was provided by sensitization of the sensor surface with aptamers against HCVcoreAg. The influence of buffer pH on the sensor response signal was studied. The effect of reverse polarity of the biosensor response signal with change from the acidic buffer pH to the neutral one was found. The lowest detectable HCVcoreAg concentration was determined to be 2.0 × 10−15 M in both acidic (pH 5.1) and neutral (pH 7.4) buffer solution. The proposed aptamer-sensitized sensor was also successfully applied to detect HCVcoreAg in serum samples of hepatitis C patients.
Study on the Nondestructive Measurement of Aluminized Thickness Based on Radial Basis Function Neural Network by X-ray Fluorescence
Authors: Liu Jichao , Wang Cheng , Zhang Peiyu , Gui Min , Tong Lijia , Li Bin
Published: August 2020

Aluminizing is a common protective coating for aeroengine turbine blades, but there is no method to accurately measure the aluminized thickness. X-ray fluorescence nondestructive testing technology is a method which can basically realize the measurement of all coatings on the metal substrate. However, the aluminized coating structure is completely different from the conventional coating structure, which causes great difficulties in measuring the aluminized thickness by conventional calculation models. Therefore, to realize the measurement of aluminized thickness, a new modeling method based on radial basis function (RBF) neural network by X-ray fluorescence (XRF) is proposed. By comparing two calculation models of RBF and principal component analysis (PCA)-RBF, the results show that both models can realize the measurement of aluminized thickness, but the accuracy of PCA-RBF is better than that of RBF, and the average relative error of the predicted results is 3.99%; the predicted results of the PCA-RBF model fit the training values better, and its predictability is better.
Increasing Innovative Working Behaviour of Information Technology Employees in Vietnam by Knowledge Management Approach
Authors: Pham Quoc Trung , Pham-Nguyen Anh-Vu , Misra Sanjay , Damaševičius Robertas
Published: August 2020

Today, Knowledge Management (KM) is becoming a popular approach for improving organizational innovation, but whether encouraging knowledge sharing will lead to a better innovative working behaviour of employees is still a question. This study aims to identify the factors of KM affecting the innovative working behaviour of Information Technology (IT) employees in Vietnam. The research model involves three elements: attitude, subjective norm and perceived behavioural control affecting knowledge sharing, and then, on innovative working behaviour. The research method is the quantitative method. The survey was conducted with 202 samples via the five-scale questionnaire. The analysis results show that knowledge sharing has a positive impact on the innovative working behaviour of IT employees in Vietnam. Besides, attitude and perceived behavioural control are confirmed to have a strong positive effect on knowledge sharing, but the subjective norm has no significant impact on knowledge sharing. Based on this result, recommendations to promote knowledge sharing and the innovative work behaviour of IT employees in Vietnam are made.
Salicylate UV-Filters in Sunscreen Formulations Compromise the Preservative System Efficacy against Pseudomonas aeruginosa and Burkholderia cepacia
Authors: Ziklo Noa , Tzafrir Inbal , Shulkin Regina , Salama Paul
Published: August 2020

Contamination of personal-care products are a serious health concern and therefore, preservative solutions are necessary for the costumers’ safety. High sun protection factor (SPF) sunscreen formulations are known to be difficult to preserve, due to their high ratio of organic phase containing the UV-filters. Salicylate esters such as octyl salicylate (OS) and homosalate (HS) are among the most common UV-filters currently used in the market, and can undergo hydrolysis by esterase molecules produced by contaminant microorganisms. The hydrolysis product, salicylic acid (SA) can be assimilated by certain bacteria that contain the chorismate pathway, in which its final product is pyochelin, an iron-chelating siderophore. Here, we show that OS and HS can compromise the preservative efficacy against two pathogenic important bacteria, Pseudomonas aeruginosa and Burkholderia cepacia. Challenge tests of formulations containing the UV-filters demonstrated that only bacteria with the chorismate pathway failed to be eradicated by the preservation system. mRNA expression levels of the bacterial pchD gene, which metabolizes SA to produce pyochelin, indicate a significant increase that was in correlation with increasing concentrations of both OS and HS. These data suggest that certain UV-filters can provide a source for bacterial resistance against common preservatives in sunscreen formulations.
Monosulfonated Azo Dyes: A Crystallographic Study of the Molecular Structures of the Free Acid, Anionic and Dianionic Forms
Authors: Kennedy Alan R. , Conway Linda K. , Kirkhouse Jennifer B. A. , McCarney Karen M. , Puissegur Olivier , Staunton Edward , Teat Simon J. , Warren John E.
Published: August 2020

Crystallographic studies of monosulfonated azo dyes have concentrated on the salt forms that contain the azo anion. Here we present a study that compares the structures of these anions with protonated free acid forms and with doubly deprotonated dianion forms. To this end, the new single crystal diffraction structures of 13 systematically related free acid forms of monosulfonated azo dyes are presented, together with three new structures of doubly deprotonated forms and two new structures of Na salt forms of azo anions. No structures of dideprotonated monosulfonated azo dyes have previously been reported and this paper also reports the first crystal structure of an azo dye with a hydronium cation. The geometries of the free acid, anion and dianion forms are compared to literature equivalents. It is shown that protonation of the azo bond gives predictable bond lengthening and shortening, which is of a greater magnitude than similar effects caused by azo-hydrazone tautomerisation, or the smaller again effects caused by the resonance electron donation from O or N based substituents. The dianion containing structures have twisted dianion geometries that can be understood based on the resonance effects of the phenoxide groups and upon the needs to bond to a relatively high number of metal cations.
Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type
Authors: Likhanov Maxim S. , Sytov Nikita V. , Wei Zheng , Dikarev Evgeny V. , Shevelkov Andrei V.
Published: August 2020

Nowotny chimney ladder (NCL) phases are intermetallic compounds formed by transition metals and metals of groups 13 and 14. This family can be expanded by combining two p-elements from different groups with those transition metals, for which the corresponding binary NCL phases are unknown. In this paper, we present three new compounds in the V-Al-Ge, Nb-Al-Ge, and Nb-Ga-Ge systems related to the TiSi2 structure type (Sp. Gr. Fddd) obtained with the standard ampule technique. The crystal structures of the new compounds were determined using synchrotron powder X-ray diffraction data. A transition to the CrSi2 structure type was detected upon changing the composition from VAl0.72(2)Ge1.28(2) to VAl1.534(3)Ge0.466(3). According to the 18–n rule, all the compounds are metallic conductors, which was supported by the electronic structure calculations. It was shown that the expected energy gap located above the Fermi level in the vanadium-based NCL compound collapsed into a pseudogap upon the replacement of V by Nb.
Structure and Biodiversity of Rhodolith Seabeds: A Special Issue
Authors: Tuya Fernando
Published: August 2020

Rhodolith seabeds function as ‘ecosystems engineers’, which globally provide a range of ‘ecosystem services’. However, knowledge on the structure, composition and distribution of rhodolith seabeds is still lacking. This Special Issue comprises six articles, addressing specific questions of rhodolith seabeds, and covering a wide range of topics. Two papers provide new large-scale information on the presence, structure and distribution of rhodolith beds at two southern hemisphere areas, in particular continental shelfs off South Africa and Brazil. Another two studies contributed to the discovery on new algal species from rhodolith beds, including Sporolithon franciscanum, a new rhodolith-forming species from Brazil, and the small benthic alga Schizocladia ischiensis. In terms of associated fauna, the taxonomic composition and patterns of abundance of decapod crustaceans are described in another article, including the description of a depth-partitioning in the abundance of juveniles and adults of the crab Nanocassiope melanodactylus. Rhodoliths are often present in fossilized deposits, so we can track changes in their presence with climate fluctuations. High temperatures during the Eocene and widespread oligotrophic conditions are finally connected with low abundances of rhodolith beds at mid and high latitudes, despite a larger presence at equatorial regions.
Diversity of Tree Species in Gap Regeneration under Tropical Moist Semi-Deciduous Forest: An Example from Bia Tano Forest Reserve
Authors: Hammond Maame Esi , Pokorný Radek
Published: August 2020

In a quest to improve the diversity and conservation of native tree species in tropical African forests, gap regeneration remains all-important nature-promoting silviculture practice and ecosystem-based strategy for attaining these ecological goals. Nine gaps of varying sizes (286–2005 m2) were randomly selected: three each from undisturbed, slightly disturbed and disturbed areas within Bia Tano Forest Reserve of Ghana. Within individual gaps, four transects (North–South–East–West directions) followed by 10 subsampling regions of 1 m2 at 2 m apart were established along each transect. Data showed 63 tree species from 21 families in the study. Although, all estimated diversity indices showed significant biodiversity improvements in all gaps at p < 0.05 level. Yet, there were no significant variations amongst gaps. Additionally, tree species differed between gaps at the undisturbed and the two disturbance-graded areas while no differences were presented between disturbance-graded areas. Balanced conservation between Green Star and Reddish Star species and imbalanced conservation between Least Concern, Near Threatened and Vulnerable species in the International Union for Conservation of Nature (IUCN) Red List were found, showing the reserve’s long-term prospects for economic and ecological benefits of forest management. Thus, there is a need for higher priority for intensive management to regulate various anthropogenic disturbances so as to protect the biological legacies of the reserve.
Effects of Human Activities on the Diversity of Waterbirds Wintering in a Shallow Lake of the Middle and Lower Yangtze River Floodplain, China
Authors: Wang Xinjian , Chen Jinyun , Zhou Lizhi
Published: August 2020

Human activity is the major factor driving the wetland degradation in shallow lakes. Human exploitation of lake wetlands alters the habitats of wintering waterbirds, and, in turn, waterbird diversity in the shallow lakes. In the present study, we surveyed species composition, abundance, and habitat characteristics of waterbirds in three types of wetland habitats (natural lakeside wetlands, paddy fields, and aquaculture ponds) at Caizi Lake, a shallow lake in the middle and lower Yangtze River during the wintering period, and investigated the effects of habitat change driven by human activity on the diversity of wintering waterbirds. There were significant differences in species composition and abundance among the three wetland habitats (natural lakeside wetlands, aquaculture ponds, and artificial paddy fields); however, there were no significant differences among the habitats with respect to the number of waterbirds. The numbers of overwintering waterbird species and waterbird individuals in aquaculture ponds and lakeside wetlands were significantly higher than the numbers in the paddy fields, indicating that wintering waterbirds prefer natural lake wetlands and aquaculture ponds. Principal component analysis of the three wetland habitat types revealed that factors influencing waterbird diversity include wetland area, vegetation cover, water level, and degree of human interference. Therefore, minimizing human interference and ensuring suitable habitats at specific periods could facilitate the maintenance of waterbird diversity.
Modelling and Identification of the Hysteretic Dynamics of Inerters
Authors: Siami Ali , Karimi Hamid Reza
Published: August 2020

This paper deals with an experimental study on the modeling and identification of the hysterical behavior of inerters. Unlike existing methods that can only consider a constant inertance to capture a static model of the device, we develop three different dynamic models for a ball-screw type inerter. To eliminate the effects of the measurement noise, an empirical mode decomposition (EMD) method is proposed. Then, three dynamic models—the Dahl, LuGre and Bouc–Wen model—are used in order to model the friction behavior of the device. Using the least-square optimization method, the parameters of the models are estimated. The results of the tuned models are compared together within different frequencies. The good agreement between predicted and measured data shows that LuGre and Bouc–Wen models can be effective for modelling the hysteretic behavior of friction inside the inerter mechanism. It is also shown that the Bouc–Wen model has better correlation with the experimental results in all test frequencies and amplitudes.
Selected Matrix Metalloproteinases (MMP-2, MMP-7) and Their Inhibitor (TIMP-2) in Adult and Pediatric Cancer
Authors: Kaczorowska Aleksandra , Miękus Natalia , Stefanowicz Joanna , Adamkiewicz-Drożyńska Elżbieta
Published: August 2020

The tumor microenvironment (TME) consists of numerous biologically relevant elements. One of the most important components of the TME is the extracellular matrix (ECM). The compounds of the ECM create a network that provides structural and biochemical support to surrounding cells. The most important substances involved in the regulation of the ECM degradation process are matrix metalloproteinases (MMPs) and their endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs). The disruption of the physiological balance between MMP activation and deactivation could lead to progression of various diseases such as cardiovascular disease, cancer, fibrosis arthritis, chronic tissue ulcers, pathologies of the nervous system (such as stroke and Alzheimer’s disease), periodontitis, and atheroma. MMP-TIMP imbalance results in matrix proteolysis associated with various pathological processes such as tumor invasion. The present review discusses the involvement of two MMPs, MMP-2 and MMP-7, in cancer pathogenesis. These two MMPs have been proven in several studies, conducted mostly on adults, to make an important contribution to cancer development and progression. In the current review, several studies that indicate the importance of MMP-TIMP balance determination for the pediatric population are also highlighted. The authors of this review believe that carrying out biochemical and clinical studies focused on metalloproteinases and their inhibitors in tumors in children will be of great relevance for future patient diagnosis, determination of a prognosis, and monitoring of therapy.
Machine Learning Model Comparison in the Screening of Cholangiocarcinoma Using Plasma Bile Acids Profiles
Authors: Negrini Davide , Zecchin Patrick , Ruzzenente Andrea , Bagante Fabio , De Nitto Simone , Gelati Matteo , Salvagno Gian Luca , Danese Elisa , Lippi Giuseppe
Published: August 2020

Bile acids (BAs) assessments are garnering increasing interest for their potential involvement in development and progression of cholangiocarcinoma (CCA). Since machine learning (ML) algorithms are increasingly used for exploring metabolomic profiles, we evaluated performance of some ML models for dissecting patients with CCA or benign biliary diseases according to their plasma BAs profiles. We used ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for assessing plasma BAs profile in 112 patients (70 CCA, 42 benign biliary diseases). Twelve normalisation procedures were applied, and performance of six ML algorithms were evaluated (logistic regression, k-nearest neighbors, naïve bayes, RBF SVM, random forest, extreme gradient boosting). Naïve bayes, using direct bilirubin concentration for normalisation of BAs, was the ML model displaying better performance in the holdout set, with an Area Under Curve (AUC) of 0.95, 0.79 sensitivity, 1.00 specificity. This model, also characterised by 1.00 positive predictive value and 0.73 negative predictive value, displayed a globally excellent accuracy (86.4%). The accuracy of the other five models was lower, and AUCs ranged 0.75–0.95. Preliminary results of this study show that application of ML to BAs profile analysis can provide a valuable contribution for characterising bile duct diseases and identifying patients with higher likelihood of having malignant pathologies.
Imaging Software Programs for Reliable Mathematical Measurements in Orthodontics
Authors: Radwan Eman Saad , Scribante Andrea , Sfondrini Maria Francesca , Montasser Mona A
Published: August 2020

Aim: To evaluate the reliability of linear and angular measurements taken using different software programs in orthodontics. Materials and Methods: A sample of four software programs from different manufacturers, namely MicroDicom viewer, Photoshop® CS3, AutoCAD®, and Image-Pro®, were used for measuring the geometric features of four types of miniscrews from different manufacturers. Each miniscrew type presented a group: Group I, Tomas® (Dentaurum, Ispringen, Germany); Group II, HUBIT® (HUBIT, Gyeonggi-do, Korea); Group III, AbsoAnchor® (Dentos, Daegu, Korea); and Group IV, Creative (Creative, Zhejiang, China). Measurements of apical face angle, thread angle, lead angle, flank, pitch depth, and width were taken on 45 × magnification scanning electron microscope images of the shafts of the miniscrews. One assessor measured the seven geometric features for the four types of miniscrews using the four software programs twice in two sessions separated by a three week interval. Results: Pairwise comparisons, for each of the four miniscrew groups, showed that the only common result observed was the significant difference (p < 0.001) between measurements of flank taken by the four software programs. When measurements of the four types of miniscrews were pooled into one group, a high degree of intra-rater reliability (ICC range from 0.9 to 1.0) for all the seven geometric features was found with all the four software programs. The paired t-test showed insignificant difference (at p ≤ 0.05) between the first and second measurements, except for a few measurements including pitch width measured by Image-Pro® (p = 0.012), MicroDicom (p = 0.023), and Photoshop® (p = 0.001). Conclusions: Results did not give absolute superiority to one software program over the others and suggested an assessor effect. Assessor estimates could have been affected, among other factors, by the design of the miniscrews and the technical features of the software programs.
Developing Person-Centred Dental Care: The Perspectives of People Living in Poverty
Authors: Noushi Nioushah , Bedos Christophe
Published: August 2020

Dentistry has seen a slow trend toward person-centred care (PCC), with most approaches developed by scholars who have tried to progress away from disease-centred care. Unfortunately, the perspectives and experiences of underprivileged people have not been considered in the development of these approaches. Our objective was thus to understand underprivileged people’s experiences and expectations about dental care and contribute to the development of person-centred dentistry. We conducted a qualitative descriptive study with a sample of 13 people living in poverty. We used a maximum variation sampling strategy and selected them among the users of a free dental clinic in Montreal, Canada. We conducted semi-structured interviews that we audio recorded, transcribed verbatim, and thematically analysed. Our main finding is that participants wanted to feel human and respected by dentists. More specifically, they wanted to be more involved in the dental care process through quality time and empathetic conversations with the dentist. They also wished for an exchange of information free of technical terms and built on mutual trust. In conclusion, person-centred dental care models should emphasize empathy, trust, and quality care beyond technical skills. Clinicians should provide comprehensive information in dental encounters and treat their patients as whole persons.
The Association between D-Dimer and Prognosis in the Patients with Oral Cancer
Authors: Yamagata Kenji , Fukuzawa Satoshi , Ishibashi-Kanno Naomi , Uchida Fumihiko , Yanagawa Toru , Bukawa Hiroki
Published: August 2020

D-dimer levels are reported to relate with tumor stage, prognosis, and lymph node involvement, as well as overall survival (OS) in patients with solid tumors. The purpose of this study was to investigate association between the value of D-dimer and the prognosis of oral cancer (OC). We designed a retrospective cohort study and enrolled a sample of patients who were diagnosed with OC and treated with surgery and/or radiotherapy. The predictor was the D-dimer and outcome variable was OS. Other variables included age, neutrocyte count, neutrophil lymphocyte ratio (NLR), C-reactive protein (CRP), and management. Differences in OS rate were analyzed by log-rank test. A Cox proportional hazards model was used to adjust for the effects of potential confounders. Differences with a P value less than 0.05 were considered statistically significant. In 88 patients with OC, D-dimer median value for the predicting OS was 0.7 µg/mL. There was a significant difference in OS when patients were stratified according to D-dimer, with an OS rate of 77.8% for patients with low D-dimer (<0.7), and 57.3% with high D-dimer (≥0.7) (p = 0.035). Univariate analyses revealed close correlations between OS and age, neutrocyte count, NLR, CRP, and D-dimer (<0.7 and ≥0.7). Cox multivariate analysis identified management (mainly surgery vs. radiotherapy) (HR 3.274, 95% CI 1.397–7.676; p = 0.006) as independent predictive factors for OS. There was a significant difference in OS when patients were stratified according to D-dimer with low (<0.7) and high D-dimer (≥0.7) (p = 0.035). Though, as a predictive factor, management was associated with OS.
The Impact of Russia’s Import Embargo on the EU Countries’ Exports
Authors: Skvarciany Viktorija , Jurevičienė Daiva , Vidžiūnaitė Silvija
Published: August 2020

Political unrest inevitably has consequences for a national economy. International trade in a globalised world has great importance for countries. Unfortunately, due to various political events, countries apply some restrictions to each other. In 2014, Western countries imposed sanctions on trade with Russia, due to the annexation of Crimea. As a response, Russia announced an embargo on importing of some goods from European and North American countries, as well as Australia. The current study investigates the economic impact on EU countries due to the mentioned embargo. The EU countries were grouped according to the average for 1998–2018 exports of products to Russia using a cluster analysis. After the clustering, the gravity model was employed to develop the equations representing the international trade between each cluster and Russia. Although Russia declared an embargo on countries associated with the same group of goods, the economic impact on their economies was different. This study has a couple of limitations. The research reflects only the impact of the embargo on exports regardless of some possible indirect effects; the study assesses the export of all sectors due to limited data; and because the restrictions are applied only to the food sector, the research shows only relative changes in exports.
Quasi-Z Source T-Type Power Converter for PV Based Commercial and Industrial Nanogrids with Active Functions Strategy
Authors: Barrero-González Fermín , Roncero-Clemente Carlos , Milanés-Montero María Isabel , González-Romera Eva , Romero-Cadaval Enrique , Husev Oleksandr
Published: August 2020

Since most power electronics used in photovoltaic (PV) inverters at commercial and industrial facilities exhibit behavior as non-linear loads from the grid side, these high-power demand installations are expected to have a major impact on the network’s power quality. In an attempt to facilitate their integration into the distribution grid, this paper presents a comprehensive control strategy for Quasi-Z Source T-Type PV inverters inside a facility, which performs active and reactive power control, and harmonic and imbalance compensation at expenses of the spare inverter power capacity. Unlike other approaches, the one proposed here operates properly under distorted and unbalanced grid voltages. The electrical network structure inside a commercial and industrial facility is considered, analyzing the operation of the proposed strategy on three-phase PV inverters. The power topology used has voltage boosting ability, which eliminates the requirement for both an additional DC-DC converter and/or a step-up transformer commonly used in PV inverter systems. The proposed strategy performance is demonstrated on a 50 kW converter model under a disturbed grid environment and changing load conditions.
Counteracting UDP Flooding Attacks in SDN
Authors: Tung Yung-Hao , Wei Hung-Chuan , Ti Yen-Wu , Tsou Yao-Tung , Saxena Neetesh , Yu Chia-Mu
Published: August 2020

Software-defined networking (SDN) is a new networking architecture with a centralized control mechanism. SDN has proven to be successful in improving not only the network performance, but also security. However, centralized control in the SDN architecture is associated with new security vulnerabilities. In particular, user-datagram-protocol (UDP) flooding attacks can be easily launched and cause serious packet-transmission delays, controller-performance loss, and even network shutdown. In response to applications in the Internet of Things (IoT) field, this study considers UDP flooding attacks in SDN and proposes two lightweight countermeasures. The first method sometimes sacrifices address-resolution-protocol (ARP) requests to achieve a high level of security. In the second method, although packets must sometimes be sacrificed when undergoing an attack before starting to defend, the detection of the network state can prevent normal packets from being sacrificed. When blocking a network attack, attacks from the affected port are directly blocked without affecting normal ports. The performance and security of the proposed methods were confirmed by means of extensive experiments. Compared with the situation where no defense is implemented, or similar defense methods are implemented, after simulating a UDP flooding attack, our proposed method performed better in terms of the available bandwidth, central-processing-unit (CPU) consumption, and network delay time.
Large Dynamic Current Monitoring for UAV Steering Motor Using Twin Nonlinear Shunt
Authors: Li Bo , Zhang Shengbing , Zhang Hanlu , Wang Shiyu , He Feng
Published: August 2020

Steering motor is of vital importance in UAV’s health-monitoring system, to which its supply current is the most critical characteristic representing health statue of UAV. In order to conduct continuous measuring on the steering motor’s current of large dynamic range, in this paper, a current measurement method is therefore proposed on the basis of twin nonlinear shunt. The proposed method adopts the twin diode as the current sampling device, which not only realizes measurement range and relative constant resolution, but also ensures continuity of the measurement due to the eliminated operation of range switching. The associated diode is used to compensate the temperature of core temperature of the shunt diode, and to make the nonlinear-shunt more adaptive for the case of junction being heated under larger current. The working principle, real-time compensation method and circuit implementation of our method are discussed in detail. Experimental test results suggest that the measurement error of the proposed method is less than 4.5% when the measurement current varies between 10 mA to 10 A, maintaining the relative resolution at an almost constant level, while preventing the conventional method of frequent range switching from generating glitches. In addition to the ensured continuity, information-rich details of the current are sustained, contributing to the UAV’s health-monitoring system. The proposal can also be applied to other applications concerning large dynamic current detection, including, but not limited to, industrial control, motor control, etc.
Assessment of Practical Methods to Predict Accumulated Rotations of Monopile-Supported Offshore Wind Turbines in Cohesionless Ground Profiles
Authors: Jalbi Saleh , Hilton Joseph , Jacques Luke
Published: August 2020

Monopiles supporting offshore wind turbines can experience permanent non-recoverable rotations (or displacements) during their lifetime due to the cyclic nature of hydrodynamic and aerodynamic loading exerted on them. Recent studies in the literature have demonstrated that conventional cyclic p–y curves recommended in different codes of practice (API-RP-2GEO and DNVGL-RP-C212) may not capture the effects of long-term cyclic loads as they are independent of the loading profile and the number of applied cycles. Several published methodologies based on laboratory scaled model tests (on sands) exist to determine the effect of cyclic lateral loads on the long-term behaviour of piles. The tests vary in terms of the pile behaviour (rigid or flexible pile), number of applied loading cycles, and the load profile (one-way or two-way loading). The best-fit curves provided by these tests offer practical and cost-efficient methods to quantify the accumulated rotations when compared to Finite Element Method. It is therefore desirable that such methods are further developed to take into account different soil types and the complex nature of the loading. The objective of this paper is to compare the performance of the available formulations under the actions of a typical 35-h (hour) storm as per the Bundesamt für Seeschifffahrt und Hydrographie (BSH) recommendations. Using classical rain flow counting, the loading time-history is discretized into load packets where each packet has a loading profile and number of cycles, which then enables the computation of an equivalent number of cycles of the largest load packet. The results show that the loading profile plays a detrimental role in the result of the accumulated rotation. Furthermore, flexibility of the pile also has an important effect on the response of the pile where predictions obtained from formulations based on flexible piles resulted in a much lower accumulated rotation than tests based on rigid piles. Finally, the findings of this paper are expected to contribute in the design and interpretation of future experimental frameworks for Offshore Wind Turbine (OWT) monopiles in sands, which will include a more realistic loading profile, number of cycles, and relative soil to pile stiffness.
Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process
Authors: Calise Francesco , Eicker Ursula , Schumacher Juergen , Vicidomini Maria
Published: August 2020

The aim of the present paper is to develop a reliable and accurate model of the wastewater biochemical treatment process and to explore the behaviour through a general dynamic simulation environment, namely the INtegrated Simulation Environment Language (INSEL), for the analysis of the energy demand of the whole wastewater treatment plant. In particular, the presented model pays special attention to the chemical kinetics involved in the activated sludge process for the reduction of nitrogen and carbon compounds. According to the best practices, the plant configuration considered in this work includes the denitrification-nitrification process, performed by completely mixed reactors. In particular, the process analysed in this paper is based on the Ludzak-Ettinger process. The biological process is simulated according to the well-known method widely used in the literature, namely the Activated Sludge Model No 1 (ASM1). The model includes a set of equations for the calculation of aerobic growth of heterotrophs, anoxic growth of heterotrophs, aerobic growth of autotrophs, decay of autotrophs, ammonification of soluble nitrogen, hydrolysis of entrapped organics, and hydrolysis of entrapped organic nitrogen. All these equations, along with energy and mass balances, are solved by the explicit Euler method. The developed model is validated using literature data, showing a great accuracy (deviation below 1%). As for the temperature, results show that, between 15 and 25 °C, in the initial part of the process, transport effects dominate the consumption ones. When the temperature is higher than 30 °C, nitrate consumption is so fast that biomass growth is limited by this effect. Conversely, in case of low temperatures (5–10 °C), biomass growth is not limited by nitrate availability. Finally, results also showed that temperature significantly affects the denitrification process, whereas the effect on the oxygen is lower.