bluuebunny/crossref_metadata_2025 huggingface dataset:
A Chopper Stabilization Audio Instrumentation Amplifier for IoT Applications
Authors: Nebhen Jamel , Ferreira Pietro M. , Mansouri Sofiene
Published: April 2020

A low-noise instrumentation amplifier dedicated to a nano- and micro-electro-mechanical system (M&NEMS) microphone for the use in Internet of Things (IoT) applications is presented. The piezoresistive sensor and the electronic interface are respectively, silicon nanowires and an instrumentation amplifier. To design an instrumentation amplifier for IoT applications, different trade-offs are discussed like power consumption, gain, noise and sensitivity. Because the most critical noisy block is the amplifier, a delay-time chopper stabilization (CHS) technique is implemented around it to eliminate its offset and 1/f noise. The low-noise instrumentation amplifier is implemented in a 65-nm CMOS (Complementary metal–oxide–semiconductor) technology. The supply voltage is 2.5 V while the power consumption is 0.4 mW and the core area is 1 mm2. The circuit of the M&NEMS microphone and the amplifier was fabricated and measured. From measurement results over a signal bandwidth of 20 kHz, it achieves a signal-to-noise ratio (SNR) of 77 dB.
Material Discovery and High Throughput Exploration of Ru Based Catalysts for Low Temperature Ammonia Decomposition
Authors: McCullough Katherine , Chiang Pei-Hua , Jimenez Juan D. , Lauterbach Jochen A.
Published: April 2020

High throughput experimentation has the capability to generate massive, multidimensional datasets, allowing for the discovery of novel catalytic materials. Here, we show the synthesis and catalytic screening of over 100 unique Ru-Metal-K based bimetallic catalysts for low temperature ammonia decomposition, with a Ru loading between 1–3 wt% Ru and a fixed K loading of 12 wt% K, supported on γ-Al2O3. Bimetallic catalysts containing Sc, Sr, Hf, Y, Mg, Zr, Ta, or Ca in addition to Ru were found to have excellent ammonia decomposition activity when compared to state-of-the-art catalysts in literature. Furthermore, the Ru content could be reduced to 1 wt% Ru, a factor of four decrease, with the addition of Sr, Y, Zr, or Hf, where these secondary metals have not been previously explored for ammonia decomposition. The bimetallic interactions between Ru and the secondary metal, specifically RuSrK and RuFeK, were investigated in detail to elucidate the reaction kinetics and surface properties of both high and low performing catalysts. The RuSrK catalyst had a turnover frequency of 1.78 s−1, while RuFeK had a turnover frequency of only 0.28 s−1 under identical operating conditions. Based on their apparent activation energies and number of surface sites, the RuSrK had a factor of two lower activation energy than the RuFeK, while also possessing an equivalent number of surface sites, which suggests that the Sr promotes ammonia decomposition in the presence of Ru by modifying the active sites of Ru.
An Improved Lagrangian-Inverse Method for Evaluating the Dynamic Constitutive Parameters of Concrete
Authors: Yu Xinlu , Fu Yingqian , Dong Xinlong , Zhou Fenghua , Ning Jianguo
Published: April 2020

The dynamic constitutive behaviors of concrete-like materials are of vital importance for structure designing under impact loading conditions. This study proposes a new method to evaluate the constitutive behaviors of ordinary concrete at high strain rates. The proposed method combines the Lagrangian-inverse analysis method with optical techniques (ultra-high-speed camera and digital image correlation techniques). The proposed method is validated against finite-element simulation. Spalling tests were conducted on concretes where optical techniques were employed to obtain the high-frequency spatial and temporal displacement data. We then obtained stress–strain curves of concrete by applying the proposed method on the results of spalling tests. The results show non-linear constitutive behaviors in these stress–strain curves. These non-linear constitutive behaviors can be possibly explained by local heterogeneity of concrete. The proposed method provides an alternative mean to access the dynamic constitutive behaviors which can help future structure designing of concrete-like materials.
NiO Grained-Flowers and Nanoparticles for Ethanol Sensing
Authors: Carbone Marilena , Tagliatesta Pietro
Published: April 2020

Grained-flower and nanoparticles NiO samples were synthesized with a straightforward, surfactant-free hydrothermal procedure, and probed with respect to ethanol gas-sensing. Both morphologies displayed excellent performances in terms of gas response vs. temperature and concentration and are very reproducible. The grained-flower, however, performed better than the nanoparticles NiO, probably due to the shorter travelling distance of the electrons and/or adsorbates during the detection process. Both sensors displayed high stability over three weeks. The grained-flower NiO sensor also has a good selectivity.
Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand
Authors: Galangau Olivier , Flores Gonzalez Jessica , Montigaud Vincent , Dorcet Vincent , le Guennic Boris , Cador Olivier , Pointillart Fabrice
Published: April 2020

The two mononuclear complexes of the formula [Dy(tta)3(L)] (1) and [Dy(hfac)3(L)] (2) (where tta- = 2-thenoytrifluoroacetylacetonate and hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate) were obtained from the coordination reaction of the Dy(tta)3·2H2O or Dy(hfac)3·2H2O units with the 1,10-phenantroline-5,6-dione ligand (L). Their structures have been determined by X-ray diffraction studies on single crystals, and they revealed a supramolecular assembly of tetramers through σ-π interactions. Both complexes displayed a Single-Molecule Magnet (SMM) behavior without an external applied magnetic field. Magnetic relaxation happened through Orbach, Raman and Quantum Tunneling of the Magnetization (QTM). Wavefunction theory calculations were realized to rationalize the magnetic properties.
On the Solvability of Fourth-Order Two-Point Boundary Value Problems
Authors: Agarwal Ravi P. , Kelevedjiev Petio S.
Published: April 2020

In this paper, we study the solvability of various two-point boundary value problems for x ( 4 ) = f ( t , x , x ′ , x ″ , x ‴ ) , t ∈ ( 0 , 1 ) , where f may be defined and continuous on a suitable bounded subset of its domain. Imposing barrier strips type conditions, we give results guaranteeing not only positive solutions, but also monotonic ones and such with suitable curvature.
Benefits and Limitations of the Artificial with Respect to the Traditional Learning of Mathematics
Authors: Voskoglou Michael Gr. , Salem Abdel-Badeeh M.
Published: April 2020

The present article focuses on the role that the artificial teaching and learning of mathematics could play for education in the forthcoming era of a new industrial revolution that will be characterized by the development of an advanced Internet of things and energy, and by the cyber-physical systems controlled through it. Starting with a brief review of the traditional learning theories and methods of teaching mathematics, the article continues by studying the use of computers and of applications of artificial intelligence (AI) in mathematics education. The advantages and disadvantages of artificial with respect to traditional learning in the classroom are also discussed, and the article closes with the general conclusions and a few comments on the perspectives of future research on the subject.
A New Accelerated Viscosity Iterative Method for an Infinite Family of Nonexpansive Mappings with Applications to Image Restoration Problems
Authors: Puangpee Jenwit , Suantai Suthep
Published: April 2020

The image restoration problem is one of the popular topics in image processing which is extensively studied by many authors because of its applications in various areas of science, engineering and medical image. The main aim of this paper is to introduce a new accelerated fixed algorithm using viscosity approximation technique with inertial effect for finding a common fixed point of an infinite family of nonexpansive mappings in a Hilbert space and prove a strong convergence result of the proposed method under some suitable control conditions. As an application, we apply our algorithm to solving image restoration problem and compare the efficiency of our algorithm with FISTA method which is a popular algorithm for image restoration. By numerical experiments, it is shown that our algorithm has more efficiency than that of FISTA.
Marine Collagen from Alternative and Sustainable Sources: Extraction, Processing and Applications
Authors: Coppola Daniela , Oliviero Maria , Vitale Giovanni Andrea , Lauritano Chiara , D’Ambra Isabella , Iannace Salvatore , de Pascale Donatella
Published: April 2020

Due to its unique properties, collagen is used in the growing fields of pharmaceutical and biomedical devices, as well as in the fields of nutraceuticals, cosmeceuticals, food and beverages. Collagen also represents a valid resource for bioplastics and biomaterials, to be used in the emerging health sectors. Recently, marine organisms have been considered as promising sources of collagen, because they do not harbor transmissible disease. In particular, fish biomass as well as by-catch organisms, such as undersized fish, jellyfish, sharks, starfish, and sponges, possess a very high collagen content. The use of discarded and underused biomass could contribute to the development of a sustainable process for collagen extraction, with a significantly reduced environmental impact. This addresses the European zero-waste strategy, which supports all three generally accepted goals of sustainability: sustainable economic well-being, environmental protection, and social well-being. A zero-waste strategy would use far fewer new raw materials and send no waste materials to landfills. In this review, we present an overview of the studies carried out on collagen obtained from by-catch organisms and fish wastes. Additionally, we discuss novel technologies based on thermoplastic processes that could be applied, likewise, as marine collagen treatment.
Marine Microbial Diversity as a Source of Bioactive Natural Products
Authors: Stien Didier
Published: April 2020

Some 3 [...]
Leveraging Nanocrystal HKUST-1 in Mixed-Matrix Membranes for Ethylene/Ethane Separation
Authors: Chuah Chong Yang , Samarasinghe S.A.S.C. , Li Wen , Goh Kunli , Bae Tae-Hyun
Published: April 2020

The energy-intensive ethylene/ethane separation process is a key challenge to the petrochemical industry. HKUST-1, a metal–organic framework (MOF) which possesses high accessible surface area and porosity, is utilized in mixed-matrix membrane fabrication to investigate its potential for improving the performance for C2H4/C2H6 separation. Prior to membrane fabrication and gas permeation analysis, nanocrystal HKUST-1 was first synthesized. This step is critical in order to ensure that defect-free mixed-matrix membranes can be formed. Then, polyimide-based polymers, ODPA-TMPDA and 6FDA-TMPDA, were chosen as the matrices. Our findings revealed that 20 wt% loading of HKUST-1 was capable of improving C2H4 permeability (155% for ODPA-TMPDA and 69% for 6FDA-TMPDA) without excessively sacrificing the C2H4/C2H6 selectivity. The C2H4 and C2H6 diffusivity, as well as solubility, were also improved substantially as compared to the pure polymeric membranes. Overall, our results edge near the upper bound, confirming the effectiveness of leveraging nanocrystal HKUST-1 filler for performance enhancements in mixed-matrix membranes for C2H4/C2H6 separation.
An Investigation on Wear Behavior of ER8 and SSW-Q3R Wheel Steel under Pure Rolling Condition
Authors: Zhao Hai , Liu Pengtao , Ding Yi , Jiang Bo , Liu Xuehua , Zhang Mingru , Chen Gang
Published: April 2020

In this paper, the wear property of ER8 and SSW-Q3R wheel steel under pure rolling condition was studied by GMP-30 wear tester. The results showed that the wear loss of the ER8 wheel steel was higher than that of the SSW-Q3R wheel steel at the same cycles. The high carbon content of the SSW-Q3R improved the surface hardness during rolling wear. The high hardness increased the wear resistance of the SSW-Q3R wheel steel. During rolling wear, the fatigue wear resistance of ER8 wheel was worse than that of the SSW-Q3R wheel steel due to more proeutectoid ferrite content in ER8 wheel steel. The surface residual stress of ER8 and SSW-Q3R wheel steel increased with the increase in cycles. The axial residual compressive stress on the surface of the sample was greater than the circumferential residual compressive stress. The residual stress at the trough was higher than that at the crest.
Simulation and Experimental Study on the Inhomogeneity of Mechanical Properties of Aluminum Alloy 7050 Plate
Authors: Gong Hai , Cao Xuan , Liu Yaoqiong , Wu Yunxin , Jiang Fangmin , Zhang Minghai
Published: April 2020

In this work, the finite element method simulated the symmetrical hot rolling process of 7050 aluminum alloy plate. The simulation result show that different thickness layers of 7050 aluminum alloy plate experienced different temperature and strain history in the rolling process, which leads to the difference of recrystallization fraction along the thickness direction and affects the distribution of grain size. The grain size of 7050 aluminum alloy rolled plate was obtained by the metallographic test, which was in good agreement with the simulation result. The true stress-strain curve and yield strength of 7050 aluminum alloy were acquired by hot compression test. Subsequently, a prediction model of yield strength was constructed based on the Hall–Patch relationship. The result show that the predicted inhomogeneity reached 8.7%, and the difference was about 5.3% compared with that of the experimental value.
Grain Size Distribution and Clay Mineral Distinction of Rare Earth Ore through Different Methods
Authors: Chen Lingkang , Jin Xiongwei , Chen Haixia , He Zhengwei , Qiu Lanrong , Duan Hurong
Published: April 2020

Although clay mineral content in ion-absorbed rare earth ores is crucial for migrating and releasing rare earth elements, the formation, distribution, and migration of clay minerals in supergene rare earth ores have not been fully understood. Therefore, this study analyzes the characteristics of clay mineral type and content, soil particle size, pH value, leaching solution concentration, and leaching rate. This analysis was performed using different methods, such as regional rare earth mine soil surveys, in situ leaching profile monitoring, and indoor simulated leaching. The results showed that the grain size and volume curve of rare earth ore have unimodal and bimodal shapes, respectively. X-ray diffraction showed the differences in clay mineral types formed by different weathered bedrocks. The principal clay minerals were kaolinite, illite, chlorite, and vermiculite, with their relative abundance varying with parent rock lithology (granite and low-grade metamorphic rocks). In the Ganxian granite weathering profile, the kaolinite content increased from top to bottom. The decomposition of feldspar minerals to kaolinite was enhanced with an increase in the SiO2 content during weathering. The in situ leaching profile analysis showed that the kaolinite content increased initially and then decreased, whereas the illite/mica content exhibited the opposite trend. Under stable leaching solution concentration and leaching rate, clay mineral formation is favored by lower pH. Low pH, low leaching rate, and highly-concentrated leaching solution (12 wt%) resulted in a slow increase in kaolinite content in the upper part of the profile (30 cm). A lower concentration of the leaching solution (4 wt%) resulted in rapid enrichment of kaolinite after 15 days. Low pH, leaching solution concentration, and leaching rate promoted the formation of distinct kaolinite horizons. We suggest that by disregarding other control factors, rare earth recovery of over 90% can be achieved through leach mining with solutions of 8 wt% and a pH of 5 at a leaching rate of 5 mL/min.
Development of a Rapid Mass Spectrometric Determination of AMP and Cyclic AMP for PDE3 Activity Study: Application and Computational Analysis for Evaluating the Effect of a Novel 2-oxo-1,2-dihydropyridine-3-carbonitrile Derivative as PDE-3 Inhibitor
Authors: Cicalini Ilaria , De Filippis Barbara , Gambacorta Nicola , Di Michele Antonio , Valentinuzzi Silvia , Ammazzalorso Alessandra , Della Valle Alice , Amoroso Rosa , Nicolotti Orazio , Del Boccio Piero , Giampietro Letizia
Published: April 2020

A simple, quick, easy and cheap tandem mass spectrometry (MS/MS) method for the determination of adenosine monophosphate (AMP) and cyclic adenosine monophosphate (cAMP) has been newly developed. This novel MS/MS method was applied for the evaluation of the inhibitory effect of a novel 2-oxo-1,2-dihydropyridine-3-carbonitrile derivative, also named DF492, on PDE3 enzyme activity in comparison to its parent drug milrinone. Molecule DF492, with an IC50 of 409.5 nM, showed an inhibition of PDE3 greater than milrinone (IC50 = 703.1 nM). To explain the inhibitory potential of DF492, molecular docking studies toward the human PDE3A were carried out with the aim of predicting the binding mode of DF492. The presence of different bulkier decorating fragments in DF492 was pursued to shift affinity of this novel molecule toward PDE3A compared to milrinone in accordance with both the theoretical and experimental results. The described mass spectrometric approach could have a wider potential use in kinetic and biomedical studies and could be applied for the determination of other phosphodiesterase inhibitor molecules.
Volatile Profile of Mead Fermenting Blossom Honey and Honeydew Honey with or without Ribes nigrum
Authors: Chitarrini Giulia , Debiasi Luca , Stuffer Mary , Ueberegger Eva , Zehetner Egon , Jaeger Henry , Robatscher Peter , Conterno Lorenza
Published: April 2020

Mead is a not very diffused alcoholic beverage and is obtained by fermentation of honey and water. Despite its very long tradition, little information is available on the relation between the ingredient used during fermentation and the aromatic characteristics of the fermented beverage outcome. In order to provide further information, multi-floral blossom honey and a forest honeydew honey with and without the addition of black currant during fermentation were used to prepare four different honey wines to be compared for their volatile organic compound content. Fermentation was monitored, and the total phenolic content (Folin–Ciocalteu), volatile organic compounds (HS-SPME-GC-MS), together with a sensory evaluation on the overall quality (44 nontrained panelists) were measured for all products at the end of fermentation. A higher total phenolic content resulted in honeydew honey meads, as well as the correspondent honey wine prepared with black currant. A total of 46 volatile organic compounds for pre-fermentation samples and 62 for post-fermentation samples were identified belonging to higher alcohols, organic acids, esters, and terpenes. The sensory analysis showed that the difference in meads made from blossom honey and honeydew honey was perceptible by the panelists with a general greater appreciation for the traditional blossom honey mead. These results demonstrated the influences of different components in meads, in particular, the influence of honey quality. However, further studies are needed to establish the relationship between the chemical profile and mead flavor perception.
Combination Therapy of Acarbose and Cyclosporine a Ameliorates Imiquimod-Induced Psoriasis-Like Dermatitis in Mice
Authors: Chen Hsin-Hua , Lin Chi-Chien , Tung Yu-Tang , Chao Ya-Hsuan , Huang Wen-Ching , Lee Po-Ying
Published: April 2020

Moderate to severe psoriasis, an immune-mediated inflammatory disease, adversely affects patients’ lives. Cyclosporin A (CsA), an effective immunomodulator, is used to treat psoriasis. CsA is ineffective at low doses and toxic at high doses. Acarbose (Acar), a common antidiabetic drug with anti-inflammatory and immunomodulatory effects, reduces imiquimod (IMQ)-induced psoriasis severity. Combinations of systemic drugs are generally more efficacious and safer than higher doses of single drugs. We observed that mice treated with a combination of Acar (250 mg/kg) and low-dose CsA (10 or 20 mg/kg) exhibited significantly milder IMQ-induced psoriasis-like dermatitis and smoother back skin than those treated with Acar (250 mg/kg), low-dose CsA (10 or 20 mg/kg), or IMQ alone. The combination therapy significantly reduced serum and skin levels of Th17-related cytokines (interleukin (IL)-17A, IL-22, and IL-23) and the Th1-related cytokine tumor necrosis factor-α (TNF-α) compared with Acar, low-dose CsA, and IMQ alone. Additionally, the combination therapy significantly reduced the percentages of IL-17- and IL-22-producing CD4+ T-cells (Th17 and Th22 cells, respectively) and increased that of Treg cells. Our data suggested that Acar and low-dose CsA in combination alleviates psoriatic skin lesions by inhibiting inflammation. The findings provide new insights into the effects of immunomodulatory drugs in psoriasis treatment.
Increasing Complexity in Wireframe DNA Nanostructures
Authors: Piskunen Petteri , Nummelin Sami , Shen Boxuan , Kostiainen Mauri A. , Linko Veikko
Published: April 2020

Structural DNA nanotechnology has recently gained significant momentum, as diverse design tools for producing custom DNA shapes have become more and more accessible to numerous laboratories worldwide. Most commonly, researchers are employing a scaffolded DNA origami technique by “sculpting” a desired shape from a given lattice composed of packed adjacent DNA helices. Albeit relatively straightforward to implement, this approach contains its own apparent restrictions. First, the designs are limited to certain lattice types. Second, the long scaffold strand that runs through the entire structure has to be manually routed. Third, the technique does not support trouble-free fabrication of hollow single-layer structures that may have more favorable features and properties compared to objects with closely packed helices, especially in biological research such as drug delivery. In this focused review, we discuss the recent development of wireframe DNA nanostructures—methods relying on meshing and rendering DNA—that may overcome these obstacles. In addition, we describe each available technique and the possible shapes that can be generated. Overall, the remarkable evolution in wireframe DNA structure design methods has not only induced an increase in their complexity and thus expanded the prevalent shape space, but also already reached a state at which the whole design process of a chosen shape can be carried out automatically. We believe that by combining cost-effective biotechnological mass production of DNA strands with top-down processes that decrease human input in the design procedure to minimum, this progress will lead us to a new era of DNA nanotechnology with potential applications coming increasingly into view.
Natural Deep Eutectic Solvents for the Extraction of Phenyletanes and Phenylpropanoids of Rhodiola rosea L.
Authors: Shikov Alexander N. , Kosman Vera M. , Flissyuk Elena V. , Smekhova Irina E. , Elameen Abdelhameed , Pozharitskaya Olga N.
Published: April 2020

The extraction of Rhodiola rosea rhizomes using natural deep eutectic solvent (NADES) consisting of lactic acid, glucose, fructose, and water was investigated. A two-level Plackett–Burman design with five variables, followed by the steepest ascent method, was undertaken to determine the optimal extraction conditions. Among the five parameters tested, particle size, extraction modulus, and water content were found to have the highest impact on the extrability of phenyletanes and phenylpropanoids. The concentration of active compounds was analyzed by HPLC. The predicted results showed that the extraction yield of the total phenyletanes and phenylpropanoids (25.62 mg/g) could be obtained under the following conditions: extraction time of 154 min, extraction temperature of 22 °C, extraction modulus of 40, molar water content of 5:1:11 (L-lactic acid:fructose:water, mol/mol), and a particle size of rhizomes of 0.5–1 mm. These predicted values were further verified by validation experiments in predicted conditions. The experimental yields of salidroside, tyrosol, rosavin, rosin, cinnamyl alcohol and total markers (sum of phenyletanes and phenylpropanoids in mg/g) were 11.90 ± 0.02, 0.36 ± 0.02, 12.23 ± 0.21, 1.41 ± 0.01, 0.20 ± 0.01, and 26.10 ± 0.27 mg/g, respectively, which corresponded well with the predicted values from the models.
Protein-Protein Interactions Prediction Based on Graph Energy and Protein Sequence Information
Authors: Xu Da , Xu Hanxiao , Zhang Yusen , Chen Wei , Gao Rui
Published: April 2020

Identification of protein-protein interactions (PPIs) plays an essential role in the understanding of protein functions and cellular biological activities. However, the traditional experiment-based methods are time-consuming and laborious. Therefore, developing new reliable computational approaches has great practical significance for the identification of PPIs. In this paper, a novel prediction method is proposed for predicting PPIs using graph energy, named PPI-GE. Particularly, in the process of feature extraction, we designed two new feature extraction methods, the physicochemical graph energy based on the ionization equilibrium constant and isoelectric point and the contact graph energy based on the contact information of amino acids. The dipeptide composition method was used for order information of amino acids. After multi-information fusion, principal component analysis (PCA) was implemented for eliminating noise and a robust weighted sparse representation-based classification (WSRC) classifier was applied for sample classification. The prediction accuracies based on the five-fold cross-validation of the human, Helicobacter pylori (H. pylori), and yeast data sets were 99.49%, 97.15%, and 99.56%, respectively. In addition, in five independent data sets and two significant PPI networks, the comparative experimental results also demonstrate that PPI-GE obtained better performance than the compared methods.
Influence of Experimental Parameters of a Continuous Flow Process on the Properties of Very Small Iron Oxide Nanoparticles (VSION) Designed for T1-Weighted Magnetic Resonance Imaging (MRI)
Authors: Vangijzegem Thomas , Stanicki Dimitri , Panepinto Adriano , Socoliuc Vlad , Vekas Ladislau , Muller Robert N. , Laurent Sophie
Published: April 2020

This study reports the development of a continuous flow process enabling the synthesis of very small iron oxide nanoparticles (VSION) intended for T1-weighted magnetic resonance imaging (MRI). The influence of parameters, such as the concentration/nature of surfactants, temperature, pressure and the residence time on the thermal decomposition of iron(III) acetylacetonate in organic media was evaluated. As observed by transmission electron microscopy (TEM), the diameter of the resulting nanoparticle remains constant when modifying the residence time. However, significant differences were observed in the magnetic and relaxometric studies. This continuous flow experimental setup allowed the production of VSION with high flow rates (up to 2 mL·min−1), demonstrating the efficacy of such process compared to conventional batch procedure for the scale-up production of VSION.
Preparation and Properties of 2D Materials
Authors: Cho Byungjin , Kim Yonghun
Published: April 2020

Since the great success of graphene, atomically thin layered nanomaterials—called two-dimensional (2D) materials—have attracted tremendous attention due to their extraordinary physical properties [...]
Highly Conductive PDMS Composite Mechanically Enhanced with 3D-Graphene Network for High-Performance EMI Shielding Application
Authors: Ao Dongyi , Tang Yongliang , Xu Xiaofeng , Xiang Xia , Yu Jingxia , Li Sean , Zu Xiaotao
Published: April 2020

A highly conductive three-dimensional (3D) graphene network (GN) was fabricated by chemical vapor deposition on a 3D nickel fiber network and subsequent etching process. Then a lightweight and flexible polydimethylsiloxane (PDMS)/GN composite was prepared by a vacuum infiltration method by using the graphene network as a template. The composite showed the superior electrical conductivity of 6100 S/m even at a very low loading level of graphene (1.2 wt %). As a result, an outstanding electromagnetic interference (EMI) shielding effectiveness (SE) of around 40 and 90 dB can be achieved in the X-band at thicknesses of 0.25 and 0.75 mm, respectively, which are much higher than most of the conductive polymers filled with carbon. The 3D graphene network can also act as a mechanical enhancer for PDMS. With a loading level of 1.2 wt %, the composite shows a significant increase by 256% in tensile strength.
Chrysin Protects against Memory and Hippocampal Neurogenesis Depletion in D-Galactose-Induced Aging in Rats
Authors: Prajit Ram , Sritawan Nataya , Suwannakot Kornrawee , Naewla Salinee , Aranarochana Anusara , Sirichoat Apiwat , Pannangrong Wanassanan , Wigmore Peter , Welbat Jariya Umka
Published: April 2020

The interruption of hippocampal neurogenesis due to aging impairs memory. The accumulation of D-galactose (D-gal), a monosaccharide, induces brain aging by causing oxidative stress and inflammation, resulting in neuronal cell damage and memory loss. Chrysin, an extracted flavonoid, has neuroprotective effects on memory. The present study aimed to investigate the effect of chrysin on memory and hippocampal neurogenesis in brains aged using D-gal. Male Sprague-Dawley rats received either D-gal (50 mg/kg) by i.p. injection, chrysin (10 or 30 mg/kg) by oral gavage, or D-gal (50 mg/kg) and chrysin (10 or 30 mg/kg) for 8 weeks. Memory was evaluated using novel object location (NOL) and novel object recognition (NOR) tests. Hippocampal neurogenesis was evaluated using Ki-67, 5-bromo-2′-deoxyuridine (BrdU), and doublecortin (DCX) immunofluorescence staining to determine cell proliferation, cell survival, and number of immature neurons, respectively. We found that D-gal administration resulted in memory impairment as measured by NOL and NOR tests and in depletions in cell proliferation, cell survival, and immature neurons. However, co-treatment with chrysin (10 or 30 mg/kg) attenuated these impairments. These results suggest that chrysin could potentially minimize memory and hippocampal neurogenesis depletions brought on by aging.
First Trimester Microelements and Their Relationships with Pregnancy Outcomes and Complications
Authors: Lewandowska Małgorzata , Więckowska Barbara , Sajdak Stefan , Lubiński Jan
Published: April 2020

Microelements involved in the oxidative balance have a significant impact on human health, but their role in pregnancy are poorly studied. We examined the relationships between first trimester levels of selenium (Se), iron (Fe), zinc (Zn), and copper (Cu), as well as maternal characteristics and pregnancy results. The data came from a Polish prospective cohort of women in a single pregnancy without chronic diseases. A group of 563 women who had a complete set of data, including serum microelements in the 10–14th week was examined, and the following were found: 47 deliveries <37th week; 48 cases of birth weight <10th and 64 newborns >90th percentile; 13 intrauterine growth restriction (IUGR) cases; 105 gestational hypertension (GH) and 15 preeclampsia (PE) cases; and 110 gestational diabetes mellitus (GDM) cases. The microelements were quantified using mass spectrometry. The average concentrations (and ranges) of the elements were as follows: Se: 60.75 µg/L (40.91–125.54); Zn: 618.50 µg/L (394.04–3238.90); Cu: 1735.91 µg/L (883.61–3956.76); and Fe: 1018.33 µg/L (217.55–2806.24). In the multivariate logistic regression, we found that an increase in Se of 1 µg/L reduces the risk of GH by 6% (AOR = 0.94; p = 0.004), the risk of IUGR by 11% (AOR = 0.89; p = 0.013), and the risk of birth <34th week by 7% (but close to the significance) (AOR = 0.93; p = 0.061). An increase in Fe of 100 µg/L reduces the risk of PE by 27% (AOR = 0.73; p = 0.009). In the multivariable linear regression, we found negative strong associations between prepregnancy BMI, Se (β = −0.130; p = 0.002), and Fe (β = −0.164; p < 0.0001), but positive associations with Cu (β = 0.320; p < 0.000001). The relationships between Se and maternal age (β = 0.167; p < 0.0001), Se and smoking (β = −0.106; p = 0.011) and Cu, and gestational age from the 10–14th week (β = 0.142; p < 0.001) were also found. Secondary education was associated with Zn (β = 0.132; p = 0.004) and higher education was associated with Cu (β = −0.102; p = 0.023). A higher financial status was associated with Fe (β = 0.195; p = 0.005). Other relationships were statistically insignificant. Further research is needed to clarify relationships between first trimester microelements and pregnancy complications. In addition, attention should be paid to lifestyle-related and socioeconomic factors that affect microelement levels.
African Sorghum-Based Fermented Foods: Past, Current and Future Prospects
Authors: Adebo Oluwafemi Ayodeji
Published: April 2020

Sorghum (Sorghum bicolor) is a well-known drought and climate resistant crop with vast food use for the inhabitants of Africa and other developing countries. The importance of this crop is well reflected in its embedded benefits and use as a staple food, with fermentation playing a significant role in transforming this crop into an edible form. Although the majority of these fermented food products evolve from ethnic groups and rural communities, industrialization and the application of improved food processing techniques have led to the commercial success and viability of derived products. While some of these sorghum-based fermented food products still continue to bask in this success, much more still needs to be done to further explore evolving techniques, technologies and processes. The addition of other affordable nutrient sources in sorghum-based fermented foods is equally important, as this will effectively augment the intake of a nutritionally balanced product.
Evaluating Diet Quality of Canadian Adults Using Health Canada’s Surveillance Tool Tier System: Findings from the 2015 Canadian Community Health Survey-Nutrition
Authors: Hack Salma , Jessri Mahsa , L’Abbé Mary R.
Published: April 2020

The 2014 Health Canada’s Surveillance Tool, Tier System (HCST) is a nutrient profiling model developed to evaluate adherence of food choices to dietary recommendations. With the recent release of the nationally representative Canadian Community Health Survey-Nutrition (CCHS-N) 2015, this study used HCST to evaluate nutritional quality of the dietary intakes of Canadians in the CCHS-N. Dietary intakes were ascertained using 24-hour dietary recalls from Canadians adults ≥19 years (N = 13,605). Foods were categorized into four Tiers based on degree of adherence to dietary recommendations according to thresholds for sodium, total fat, saturated fats, and sugars. Tier 1 and Tier 2 represented “recommended foods”, Tier 3 represents foods to “choose less often”, and Tier 4 represented foods “not recommended”. Across all dietary reference intakes (DRI) groups, most foods were categorized as Tier 1 for Vegetable and Fruits (2.2–3.8 servings/day), Tier 2 for Grain Products (2.9–3.4 servings/day), Tier 3 for Milk and Alternatives (0.7–1 serving/day) or for Meat and Alternatives (1.1–1.6 servings/day). Consumption of foods from Tier 4 and “other foods” such as high fat/sugary foods, sugar-sweetened beverages, and alcohol, represented 24–26% and 21–23% kcal/day, for males and females, respectively. Canadians are eating more foods categorized as Tier 1–3, rather than Tier 4. Adults with the highest intakes of Tier 4 and “other foods” had lower intakes of macronutrients and increased body mass index. These findings can be used by policy makers to assist in identifying targets for food reformulation at the nutrient level and quantitative guidance to support healthy food choices.
In-Vitro Evaluation of Antioxidant, Antiproliferative and Photo-Protective Activities of Benzimidazolehydrazone Derivatives
Authors: Baldisserotto Anna , Demurtas Monica , Lampronti Ilaria , Tacchini Massimo , Moi Davide , Balboni Gianfranco , Vertuani Silvia , Manfredini Stefano , Onnis Valentina
Published: April 2020

In the search of multifunctional compounds we designed benzimidazole derivatives endowed with phenolic hydroxy groups and a hydrazone moiety as potential radical-scavenger and the antioxidant agents. The target molecules have been prepared by a simple synthetic procedure and tested for their antioxidant activity by DPPH, FRAP, and ORAC test, for photoprotective activity against UV rays and for antiproliferative activity against Colo-38 melanoma cells. Furthermore, two different dermocosmetic formulations were prepared with the compounds endowed with the best antioxidant and photoprotective profile and their release from formulation evaluated using Franz Cells system. High antioxidant activity is related to the presence of at least two hydroxy groups on arylidene moiety of benzimidazoles. Structure activity analysis revealed that the position of hydroxy groups is crucial for antioxidant activity as well as the presence of a 2-hydroxy-4-(diethylamino)arylidene group. The same correlation pattern was found to be related to photoprotective activity resulting in an UVA Protection Factor better than the commercial solar filter PBSA and antiproliferative activity against melanoma cells without producing cytotoxicity on normal keratinocytes. The release analysis indicated that high antioxidant activities are achieved with limited release at concentration compatible with the use as UV sunscreen filter.
Development of 20(S)-Protopanaxadiol-Loaded SNEDDS Preconcentrate Using Comprehensive Phase Diagram for the Enhanced Dissolution and Oral Bioavailability
Authors: Kim Young Hoon , Kim Yu Chul , Jang Dong-Jin , Min Kyoung Ah , Karmacharya Jenisha , Nguyen Thi-Thao-Linh , Maeng Han-Joo , Cho Kwan Hyung
Published: April 2020

In this study, we aimed to develop a 20(S)-protopanaxadiol (PPD)-loaded self-nanoemulsifying drug delivery system (SNEDDS) preconcentrate (PSP) using comprehensive ternary phase diagrams for enhanced solubility, physical stability, dissolution, and bioavailability. Capmul MCM C8 and Capryol 90 were selected as the oil phase owing to the high solubility of PPD in these vehicles (>15%, w/w). Novel comprehensive ternary phase diagrams composed of selected oil, surfactant, and PPD were constructed, and the solubility of PPD and particle size of vehicle was indicated on them for the effective determination of PSP. PSPs were confirmed via particle size distribution, physical stability, and scanning electron microscope (SEM) with the dispersion of water. The optimized PSP (CAPRYOL90/Kolliphor EL/PPD = 54/36/10, weight%) obtained from the six possible comprehensive ternary phase diagrams showed a uniform nanoemulsion with the particle size of 125.07 ± 12.56 nm without any PPD precipitation. The PSP showed a dissolution rate of 94.69 ± 2.51% in 60 min at pH 1.2, whereas raw PPD showed negligible dissolution. In oral pharmacokinetic studies, the PSP group showed significantly higher Cmax and AUCinf values (by 1.94- and 1.81-fold, respectively) than the raw PPD group (p < 0.05). In conclusion, the PSP formulation with outstanding solubilization, dissolution, and in-vivo oral bioavailability could be suggested using effective and comprehensive ternary phase diagrams.
Influence of Formulation Parameters on Redispersibility of Naproxen Nanoparticles from Granules Produced in a Fluidized Bed Process
Authors: Wewers Martin , Czyz Stefan , Finke Jan Henrik , John Edgar , Van Eerdenbrugh Bernard , Juhnke Michael , Bunjes Heike , Kwade Arno
Published: April 2020

The particle size reduction of active pharmaceutical ingredients is an efficient method to overcome challenges associated with a poor aqueous solubility. With respect to stability and patient’s convenience, the corresponding nanosuspensions are often further processed to solid dosage forms. In this regard, the influence of several formulation parameters (i.e., type of carrier material, type and amount of additional polymeric drying excipient in the nanosuspension) on the redispersibility of naproxen nanoparticle-loaded granules produced in a fluidized bed process was investigated. The dissolution rate of the carrier material (i.e., sucrose, mannitol, or lactose) was identified as a relevant material property, with higher dissolution rates (sucrose > mannitol > lactose) resulting in better redispersibility of the products. Additionally, the redispersibility of the product granules was observed to improve with increasing amounts of polymeric drying excipient in the nanosuspension. The redispersibility was observed to qualitatively correlate with the degree of nanoparticle embedding on the surface of the corresponding granules. This embedding was assumed to be either caused by a partial dissolution and subsequent resolidification of the carrier surface dependent on the dissolution rate of the carrier material or by resolidification of the dissolved polymeric drying excipient upon drying. As the correlation between the redispersibility and the morphology of the corresponding granules was observed for all investigated formulation parameters, it may be assumed that the redispersibility of the nanoparticles is determined by their distance in the dried state.
Characterization of Thermal Damage Due to Two-Temperature High-Order Thermal Lagging in a Three-Dimensional Biological Tissue Subjected to a Rectangular Laser Pulse
Authors: Youssef Hamdy M. , Alghamdi Najat. A.
Published: April 2020

The use of lasers and thermal transfers on the skin is fundamental in medical and clinical treatments. In this paper, we constructed and applied bioheat transfer equations in the context of a two-temperature heat conduction model in order to discuss the three-dimensional variation in the temperature of laser-irradiated biological tissue. The amount of thermal damage in the tissue was calculated using the Arrhenius integral. Mathematical difficulties were encountered in applying the equations. As a result, the Laplace and Fourier transform technique was employed, and solutions for the conductive temperature and dynamical temperature were obtained in the Fourier transform domain.
Electrically-Conductive Polyketone Nanocomposites Based on Reduced Graphene Oxide
Authors: Araya-Hermosilla Esteban Alejandro , Carlotti Marco , Picchioni Francesco , Mattoli Virgilio , Pucci Andrea
Published: April 2020

In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (Gly-Gly) via the Paal–Knorr reaction with the aim of homogenously dispersing two types of reduced graphene oxide (rGO, i.e., lrGO and hrGO, the former characterized by a lower degree of reduction in comparison to the latter) by non-covalent interactions. The functional PK30-Gly-Gly polymer was effective in preparing composites with homogeneously distributed rGO characterized by an effective percolation threshold at 5 wt. %. All the composites showed a typical semiconductive behavior and stable electrical response after several heating/cooling cycles from 30 to 115 °C. Composites made by hrGO displayed the same resistive behaviour even if flanked by a considerable improvement on conductivity, in agreement with the more reduced rGO content. Interestingly, no permanent percolative network was shown by the composite with 4 wt. % of lrGO at temperatures higher than 45 °C. This material can be used as an ON–OFF temperature sensor and could find interesting applications as sensing material in soft robotics applications.
Polish Nationwide Catholic Opinion-Forming Weeklies on Social Media—From Theoretical Introduction to Empirical Approach
Authors: Adamski Andrzej , Jupowicz-Ginalska Anna , Leonowicz-Bukała Iwona
Published: April 2020

This paper is the first part of a cycle comprising five texts on the marketing use of social media by nationwide opinion-forming Catholic weeklies in Poland. Considering the state of the research so far, it is not completely clear how to classify Catholic media profiles on social networking sites. On the one hand, the media activity of the Church is typically evangelistic in nature, but on the other hand it takes place in typically secular conditions. The evangelising role of the Catholic media cannot be separated from the opinion-forming function. The main objective of the project is, firstly, to assess the marketing potential of social media used by the aforementioned weeklies and secondly, to complement the previously described online presence of religious entities in the context of the mediatization of religions. This paper—as the theoretical background of the research—presents the detailed interdisciplinary literature review on the issues crucial for the project, as well as the methodological introduction to our study.
Introducing Spatially Distributed Fire Danger from Earth Observations (FDEO) Using Satellite-Based Data in the Contiguous United States
Authors: Farahmand Alireza , Stavros E. Natasha , Reager John T. , Behrangi Ali
Published: April 2020

Wildfire danger assessment is essential for operational allocation of fire management resources; with longer lead prediction, the more efficiently can resources be allocated regionally. Traditional studies focus on meteorological forecasts and fire danger index models (e.g., National Fire Danger Rating System—NFDRS) for predicting fire danger. Meteorological forecasts, however, lose accuracy beyond ~10 days; as such, there is no quantifiable method for predicting fire danger beyond 10 days. While some recent studies have statistically related hydrologic parameters and past wildfire area burned or occurrence to fire, no study has used these parameters to develop a monthly spatially distributed predictive model in the contiguous United States. Thus, the objective of this study is to introduce Fire Danger from Earth Observations (FDEO), which uses satellite data over the contiguous United States (CONUS) to enable two-month lead time prediction of wildfire danger, a sufficient lead time for planning purposes and relocating resources. In this study, we use satellite observations of land cover type, vapor pressure deficit, surface soil moisture, and the enhanced vegetation index, together with the United States Forest Service (USFS) verified and validated fire database (FPA) to develop spatially gridded probabilistic predictions of fire danger, defined as expected area burned as a deviation from “normal”. The results show that the model predicts spatial patterns of fire danger with 52% overall accuracy over the 2004–2013 record, and up to 75% overall accuracy during the fire season. Overall accuracy is defined as number of pixels with correctly predicted fire probability classes divided by the total number of the studied pixels. This overall accuracy is the first quantified result of two-month lead prediction of fire danger and demonstrates the potential utility of using diverse observational data sets for use in operational fire management resource allocation in the CONUS.