bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigations of Accessibility of T2/T3 Copper Center of Two-Domain Laccase from Streptomyces griseoflavus Ac-993
Authors: Gabdulkhakov Azat , Kolyadenko Ilya , Kostareva Olga , Mikhaylina Alisa , Oliveira Paulo , Tamagnini Paula , Lisov Alexander , Tishchenko Svetlana
Published: June 2019

Laccases (EC 1.10.3.2) are multicopper oxidoreductases acting on diphenols and related substances. Laccases are highly important for biotechnology and environmental remediation. These enzymes contain mononuclear one T2 copper ion and two T3 copper ions (Cu3α and Cu3β), which form the so-called trinuclear center (TNC). Along with the typical three-domain laccases Bacteria produce two-domain (2D) enzymes, which are active at neutral and basic pH, thermostable, and resistant to inhibitors. In this work we present the comparative analysis of crystal structures and catalytic properties of recombinant 2D laccase from Streptomyces griseoflavus Ac-993 (SgfSL) and its four mutant forms with replacements of two amino acid residues, located at the narrowing of the presumable T3-solvent tunnels. We obtained inactive enzymes with substitutions of His165, with Phe, and Ile170 with Ala or Phe. His165Ala variant was more active than the wild type. We suggest that His165 is a “gateway” at the O2-tunnel leading from solvent to the Cu3β of the enzyme. The side chain of Ile170 could be indirectly involved in the coordination of copper ions at the T3 center by maintaining the position of the imidazole ring of His157 that belongs to the first coordination sphere of Cu3α.
Quantitative Biology of Human Shelterin and Telomerase: Searching for the Weakest Point
Authors: Veverka Pavel , Janovič Tomáš , Hofr Ctirad
Published: June 2019

The repetitive telomeric DNA at chromosome ends is protected from unwanted repair by telomere-associated proteins, which form the shelterin complex in mammals. Recent works have provided new insights into the mechanisms of how human shelterin assembles and recruits telomerase to telomeres. Inhibition of telomerase activity and telomerase recruitment to chromosome ends is a promising target for anticancer therapy. Here, we summarize results of quantitative assessments and newly emerged structural information along with the status of the most promising approaches to telomerase inhibition in cancer cells. We focus on the mechanism of shelterin assembly and the mechanisms of how shelterin affects telomerase recruitment to telomeres, addressing the conceptual dilemma of how shelterin allows telomerase action and regulates other essential processes. We evaluate how the identified critical interactions of telomerase and shelterin might be elucidated in future research of new anticancer strategies.
The Role of the Small Bowel in Unintentional Weight Loss after Treatment of Upper Gastrointestinal Cancers
Authors: Dehestani Babak , le Roux Carel W
Published: June 2019

Upper gastrointestinal (GI) cancers are responsible for significant mortality and morbidity worldwide. To date, most of the studies focused on the treatments’ efficacy and post-treatment survival rate. As treatments improve, more patients survive long term, and thus the accompanying complications including unintentional weight loss are becoming more important. Unintentional weight loss is defined as >5% of body weight loss within 6–12 months. Malignancies, particularly GI cancers, are diagnosed in approximately 25% of patients who present with unintentional weight loss. Whereas some recent studies discuss pathophysiological mechanisms and new promising therapies of cancer cachexia, there is a lack of studies regarding the underlying mechanism of unintentional weight loss in patients who are tumor free and where cancer cachexia has been excluded. The small bowel is a central hub in metabolic regulation, energy homeostasis, and body weight control throughout the microbiota-gut-brain axis. In this narrative review article, the authors discussed the impacts of upper GI cancers’ treatment modalities on the small bowel which may lead to unintentional weight loss and some new promising therapeutic agents to treat unintentional weight loss in long term survivors after upper GI operations with curative intent.
Anti-Corrosion Property of Glass Flake Reinforced Chemically Bonded Phosphate Ceramic Coatings
Authors: Yan Ge , Wang Mingyang , Sun Tao , Li Xinping , Wang Guiming , Yin Weisong
Published: June 2019

Glass flake (GF) was used as the reinforcement in chemically bonded phosphate ceramic (CBPC) coatings to promote anti-corrosion property. The crystalline phase, curing behavior, micromorphology and electrochemical performance of the coatings were studied. The results indicate that with the addition of magnesia (MgO), a new bonding phase (Mg3(PO4)2) can be formed, which can help the CBPCs achieve a more compact and denser structure. The effect of the magnesia and the GF additives on curing behavior is obvious: the heat of reaction of the phosphate ceramic materials increases with the addition of the magnesia and the GF, which emphasizes the higher crosslinking density in the phosphate ceramic materials. The phosphate ceramic coatings with the magnesia have a higher impedance value compared with the neat phosphate ceramic coating, while the highest impedance value is obtained with increased content of GF. The corrosion mechanism is mainly contributed by the new bonding phase and GF particles, which can hinder the permeation pathway and make the permeation more circuitous.
Viscoelastic Parameters of Asphalt Mixtures Identified in Static and Dynamic Tests
Authors: Mackiewicz Piotr , Szydło Antoni
Published: June 2019

We present two methods used in the identification of viscoelastic parameters of asphalt mixtures used in pavements. The static creep test and the dynamic test, with a frequency of 10 Hz, were carried out based on the four-point bending beam (4BP). In the method identifying viscoelastic parameters for the Brugers’ model, we included the course of a creeping curve (for static creep) and fatigue hysteresis (for dynamic test). It was shown that these parameters depend significantly on the load time, method used, and temperature and asphalt content. A similar variation of parameters depending on temperature was found for the two tests, but different absolute values were obtained. Additionally, the share of viscous deformations in relation to total deformations is presented, on the basis of back calculations and finite element methods. We obtained a significant contribution of viscous deformations (about 93% for the static test and 25% for the dynamic test) for the temperature 25 °C. The received rheological parameters from both methods appeared to be sensitive to a change in asphalt content, which means that these methods can be used to design an optimal asphalt mixture composition—e.g., due to the permanent deformation of pavement. We also found that the parameters should be determined using the creep curve for the static analyses with persistent load, whereas in the case of the dynamic studies, the hysteresis is more appropriate. The 4BP static creep and dynamic tests are sufficient methods for determining the rheological parameters for materials designed for flexible pavements. In the 4BP dynamic test, we determined relationships between damping and viscosity coefficients, showing material variability depending on the test temperature.
Effect of Aging Temperature on the Microstructure and Properties of Economical Duplex Stainless Steel
Authors: Xiang Hongliang , Liu Chunyu , Deng Liping , Zheng Kaikui
Published: June 2019

In this study, NSSC 2120 economical duplex stainless steel was prepared and the effects of aging temperatures on its intermetallic phase morphology, tensile strength, elongation, corrosion resistance, and antimicrobial properties were investigated. The results revealed that after aging the sample at 650 °C, it exhibits better pitting corrosion resistance and higher tensile strength. Upon increasing the aging temperature up to 750 °C, the pitting corrosion resistance and tensile strength of the samples were decreased due to the precipitation of the ε-Cu phase in the matrix. Moreover, with the further increase in the aging temperature to 850 °C, oxides containing Mn and Cr (CrMn1.5O4) and sulfides (MnS) precipitated from the samples, further decreasing their pitting corrosion resistance and tensile strength. Upon aging the samples at 950 °C, no second phase was observed and the corrosion resistance was less than that of the sample after aging at 650 °C, but the tensile strength was greater than that of the sample after aging at 650 °C. Antibacterial test results revealed that the sample after aging at 750 °C exhibited a good antibacterial effect due to the precipitation of the rod-shaped ε-Cu phase.
Microstructural and Mechanical Properties of Alkali Activated Materials from Two Types of Blast Furnace Slags
Authors: Xing Jun , Zhao Yingliang , Qiu Jingping , Sun Xiaogang
Published: June 2019

This paper investigated the effect of blast furnace slags (BFS) characteristics on the properties achievement after being alkali activated. The physical and chemical characteristics of BFS were determined by X-ray fluorescence (XRF), X-ray Diffraction (XRD) and laser granulometry. Multi-technical characterizations using calorimetry, XRD, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG-DTG), scanning electron microscope (SEM), nitrogen sorption and uniaxial compressive strength (UCS) were applied to give an in-depth understanding of the relationship between the reaction products, microstructure and BFS characteristics. The test results show that the microstructure and mechanical properties of alkali activated blast furnace slags (BFS) highly depend on the characteristics of BFS. Although the higher content of basic oxide could accelerate the hydration process and result in higher mechanical properties, a poor thermal stabilization was observed. On the other hand, with a higher content of Fe, the hydration process in alkali activated BFS2 lasts for a longer time, contributing to a delayed compressive strength achievement.
Investigating the Effects of Fiber Reinforced Concrete on the Performance of End-Zone of Pre-Stressed Beams
Authors: Jalal Asif , Shafiq Nasir , Zahid Muhammad
Published: June 2019

This paper presents the results of the behavior of end zone of post-tensioned (PT) beams made of fiber reinforced concrete (FRC). The principal aim of using FRC was to enhance the ductility and post-cracking behavior of end-zone of post-tensioned beams. A stronger and tougher end-zone of PT-beams is necessary when it is subjected to dynamic loading. Post-tensioned (PT) beams are typically used for the construction of bridges and industrial buildings, which are often subjected to vibrations and cyclic loading. Pre-mature cracking of the end zone (EZ) of a PT-beam is considered the type of problem that may cause the structural collapse. In this research program, polyvinyl alcohol (PVA) and copper-coated steel (CCS) fibers were used in concrete for improving the EZ performance of PT-beams. The use of FRC caused a 50% reduction in the shear reinforcement within the end zone of the PT-beam, which also avoided the congestion of steel in the end zone. Hence, the concrete was placed homogeneously, and smooth finished surfaces of the beams were obtained. FRC controlled the bursting of the end zone during the transfer of the full pre-stress force, and approximately 25% increment in the strain energy of the end zone was observed, which was also found efficient in strain diminution along the length of the beam.
Void Content, Tensile, Vibration and Acoustic Properties of Kenaf/Bamboo Fiber Reinforced Epoxy Hybrid Composites
Authors: Ismail Ahmad Safwan , Jawaid Mohammad , Naveen Jesuarockiam
Published: June 2019

This study aims to investigate the void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites. The composites were made using the hand lay-up method. The weight ratios of kenaf/bamboo were 30:70, 50:50 and 70:30. Further, kenaf and bamboo composites were fabricated for the purpose of comparison. The hybridization of woven kenaf/bamboo reduced the void content. The void contents of hybrid composites were almost similar. An enhancement in elongation at break, tensile strength and modulus of hybrid composites was observed until a kenaf/bamboo ratio of 50:50. Kenaf/bamboo (50:50) hybrid composite displays the highest elongation at break, tensile strength and modulus compared to the other hybrid composites which are 2.42 mm, 55.18 MPa and 5.15 GPa, respectively. On the other hand, the highest natural frequency and damping factors were observed for Bamboo/Kenaf (30:70) hybrid composites. The sound absorption coefficient of composites were measured in two conditions: without air gap and with air gap (10, 20, 30 mm). The sound absorption coefficient for testing without air gap was less than 0.5. Introducing an air gap improved the sound absorption coefficient of all composites. Hence, hybrid kenaf/bamboo composites exhibited less void content, as well as improved tensile, vibration and acoustic properties.
Whole Genome Sequencing of the Blue Tilapia (Oreochromis aureus) Provides a Valuable Genetic Resource for Biomedical Research on Tilapias
Authors: Bian Chao , Li Jia , Lin Xueqiang , Chen Xiyang , Yi Yunhai , You Xinxin , Zhang Yiping , Lv Yunyun , Shi Qiong
Published: June 2019

Blue tilapia (Oreochromis aureus) has been an economically important fish in Asian countries. It can grow and reproduce in both freshwater and brackish water conditions, whereas it is also considered as a significant invasive species around the world. This species has been widely used as the hybridization parent(s) for tilapia breeding with a major aim to produce novel strains. However, available genomic resources are still limited for this important tilapia species. Here, we for the first time sequenced and assembled a draft genome for a seawater cultured blue tilapia (0.92 Gb), with 97.8% completeness and a scaffold N50 of 1.1 Mb, which suggests a relatively high quality of this genome assembly. We also predicted 23,117 protein-coding genes in the blue tilapia genome. Comparisons of predicted antimicrobial peptides between the blue tilapia and its close relative Nile tilapia proved that these immunological genes are highly similar with a genome-wide scattering distribution. As a valuable genetic resource, our blue tilapia genome assembly will benefit for biomedical researches and practical molecular breeding for high resistance to various diseases, which have been a critical problem in the aquaculture of tilapias.
AhlX, an N-acylhomoserine Lactonase with Unique Properties
Authors: Liu Pengfu , Chen Yan , Shao Zongze , Chen Jianwei , Wu Jiequn , Guo Qian , Shi Jiping , Wang Hong , Chu Xiaohe
Published: June 2019

N-Acylhomoserine lactonase degrades the lactone ring of N-acylhomoserine lactones (AHLs) and has been widely suggested as a promising candidate for use in bacterial disease control. While a number of AHL lactonases have been characterized, none of them has been developed as a commercially available enzymatic product for in vitro AHL quenching due to their low stability. In this study, a highly stable AHL lactonase (AhlX) was identified and isolated from the marine bacterium Salinicola salaria MCCC1A01339. AhlX is encoded by a 768-bp gene and has a predicted molecular mass of 29 kDa. The enzyme retained approximately 97% activity after incubating at 25 °C for 12 days and ~100% activity after incubating at 60 °C for 2 h. Furthermore, AhlX exhibited a high salt tolerance, retaining approximately 60% of its activity observed in the presence of 25% NaCl. In addition, an AhlX powder made by an industrial spray-drying process attenuated Erwinia carotovora infection. These results suggest that AhlX has great potential for use as an in vitro preventive and therapeutic agent for bacterial diseases.
Particle Erosion Induced Phase Transformation of Different Matrix Microstructures of Powder Bed Fusion Ti-6Al-4V Alloy Flakes
Authors: Zhao Jun-Ren , Hung Fei-Yi , Lui Truan-Sheng
Published: June 2019

In this study, powder bed fusion Ti-6Al-4V alloy flake was subjected to heat treatment at 800 °C for 4 h for inducing the complete transformation of the α’ phase into the α+β phases. An erosion experiment with 450 µm mean particle diameter of Al2O3 particles at a 90° impact on both the as- powder bed fusion (PBF) Ti-6Al-4V and the 4-h 800 °C heat-treated specimens to clarify the particle erosion-induced phase transformation behavior and its effect on mechanical properties. Particle erosion-induced phase transformation to the α phase was observed on both the as-PBF Ti-6Al-4V and the heat-treated specimens. It brought about a sequential formation from the surface to the bottom: (1) a surface softened zone, (2) a hardened zone, and (3) a hardness stabilization zone. The as-PBF Ti-6Al-4V was positively eroded by erosion particles, decreasing strength and ductility. In the case of the heat-treated specimens, we found decreased strength yet an increased ductility.
Friction Stir Spot Welding with Additional Bonding of Thick Sheet Aluminum Joints
Authors: Hatzky Marcel , Frank Antonia , Böhm Stefan
Published: June 2019

The high-strength aluminum alloys offer great potential for realizing lightweight constructions in car body construction. However, the use of aluminum alloys increases the overall thickness of the material, which poses new challenges for potential joining processes. This paper examines a process combination of friction stir spot welding (FSSW) and bonding for 4 mm EN AW 6082-T6 sheets. For the investigations, adhesive or glass beads were applied between the joining components and then the sheets were welded using FSSW. The analysis shows that the adhesive and the glass beads have a very small influence on the joint formation. The use of glass beads in FSSW with bonding is recommended because less adhesive is displaced from the joint area, which increases the joint strength. The target of obtaining high weld spot strengths without strength-reducing adhesive burn-off could not be achieved because a certain residence time is necessary to form a weld spot with high strength at this sheet thickness in order to sufficiently plasticize the material. Adhesive burn-up cannot be completely avoided. For this reason, it is necessary to weigh up which characteristics are required for the specific application and adjust the welding parameters accordingly.
Connecting Mechanism for Artificial Blood Vessels with High Biocompatibility
Authors: Watanabe Ai , Miki Norihisa
Published: June 2019

This paper proposes a connecting mechanism for artificial vessels, which can be attached/detached with ease and does not deteriorate the biocompatibility of the vessels at the joint. The inner surface of the artificial vessels is designed to have high biocompatibility. In order to make the best of the property, the proposed connecting mechanism contacts and fixes the two artificial vessels whose contacting edges are turned inside out. In this manner, blood flowing inside the vessels only has contact with the biocompatible surface. The biocompatibility, or biofouling at the joint was investigated after in vitro blood circulation tests for 72 h with scanning electron microscopy. Blood coagulation for a short term (120 min) was evaluated by activated partial thromboplastin time (APTT). A decrease of APTT was observed, although it was too small to conclude that the connector augmented the blood coagulation. The micro dialysis device which our group has developed as the artificial kidney was inserted into the blood circulation system with the connector. Decrease of APTT was similarly small. These experiments verified that the proposed connector can be readily applicable for implantable medical devices.
A Comparative Study of Different Columns Sizes for Ultrafine Apatite Flotation
Authors: Matiolo Elves , Couto Hudson Jean Bianquini , de Lira Teixeira Michelle Fernanda , de Almeida Renata Nigri , de Freitas Amanda Soares
Published: June 2019

The desliming operation to discharge ultrafine particles less than 20 µm prior to concentration by flotation is a common practice in phosphate ores beneficiation plants. The first industrial application for the beneficiation of the phosphate material with particle sizes <44 µm in Brazil was in the Araxá plant concentrator in the beginning of the 1980s. This work shows the comparative flotation results with two different phosphate slime samples (<40 µm) obtained from the Copebras (CMOC International) industrial plant located in Catalão (Goiás state, Brazil), considering a circuit with rougher/cleaner configuration with different columns sizes, as follows: Circuit 1 (rougher—4” diameter column; cleaner—2” diameter column) and circuit 2 (rougher—6” diameter column; cleaner 4” column). The results indicate that better flotation apatite recovery results were achieved for the circuit with higher size columns (6” and 4”). The results can be explained by the application of a cavitation tube in the rougher stage in the 6” column. The improved flotation performance can be attributed to increased probabilities of collision and attachment and the reduced probability of detachment by the small size bubbles generated by the cavitation tube in comparison with the bubbles produced by the porous tube of the 4” column flotation.
Selective Mineralization and Recovery of Au(III) from Multi-Ionic Aqueous Systems by Bacillus licheniformis FZUL-63
Authors: Cheng Yangjian , Ke Zhibin , Bian Xiaojing , Zhang Jianhua , Huang Zhen , Lv Yuancai , Liu Minghua
Published: June 2019

The recovery of precious metals is a project with both economic and environmental significance. In this paper, how to use bacterial mineralization to selectively recover gold from multi-ionic aqueous systems is presented. The Bacillus licheniformis FZUL-63, isolated from a landscape lake in Fuzhou University, was shown to selectively mineralize and precipitate gold from coexisting ions in aqueous solution. The removal of Au(III) almost happened in the first hour. Scanning electron microscope with X-ray energy dispersive spectroscopy (SEM/EDS-mapping) results and fourier transform infrared spectroscopy (FTIR) data show that the amino, carboxyl, and phosphate groups on the surface of the bacteria are related to the adsorption of gold ions. X-ray photoelectron spectroscopy (XPS) results implied that Au(III) ions were reduced to those that were monovalent, and the Au(I) was then adsorbed on the bacterial surface at the beginning stage (in the first hour). X-ray diffraction (XRD) results showed that the gold biomineralization began about 10 h after the interaction between Au(III) ions and bacteria. Au(III) mineralization has rarely been influenced by other co-existing metal ions. Transmission electron microscope (TEM) analysis shows that the gold nanoparticles have a polyhedral structure with a particle size of ~20 nm. The Bacillus licheniformis FZUL-63 could selectively mineralize and recover 478 mg/g (dry biomass) gold from aqua regia-based metal wastewater through four cycles. This could be of great potential in practical applications.
Environmental Impact of Mine Exploitation: An Early Predictive Methodology Based on Ore Mineralogy and Contaminant Speciation
Authors: Chopard Aurélie , Marion Philippe , Mermillod-Blondin Raphaël , Plante Benoît , Benzaazoua Mostafa
Published: June 2019

Mining wastes containing sulfide minerals can generate contaminated waters as acid mine drainage (AMD) and contaminated neutral drainage (CND). This occurs when such minerals are exposed to oxygen and water. Nowadays, mineralogical work—when it is done—is independently and differentially done according to the needs of the exploration, geotechnics, metallurgy or environment department, at different stages in the mine development process. Moreover, environmental impact assessments (EIA) are realized late in the process and rarely contain pertinent mineralogical characterization on ores and wastes, depending on countries’ regulations. Contaminant-bearing minerals are often not detected at an early stage of the mine life cycle and environmental problems could occur during production or once the mine has come to the end of its productive life. This work puts forward a more reliable methodology, based on mineralogical characterization of the ore at the exploration stages, which, in turn, will be useful for each stage of the mining project and limit the unforeseen environmental or metallurgical issues. Three polymetallic sulfide ores and seven gold deposits from various origins around the world were studied. Crushed ore samples representing feed ore of advanced projects and of production mines were used to validate the methodology with realistic cases. The mineralogical methodology consisted in chemical assays and XRD, optical microscopy, SEM and EPMA were done. Five of the ores were also submitted to geochemical tests to compare mineralogical prediction results with their experimental leaching behavior. Major, minor, and trace minerals were identified, quantified, and the bearing minerals were examined for the polluting elements (and valuables). The main conclusion is that detailed mineralogical work can avert redundant work, save time and money, and allow detection of the problems at the beginning of the mine development phase, improving waste management and closure planning.
Tissue Transparency In Vivo
Authors: Inyushin Mikhail , Meshalkina Daria , Zueva Lidia , Zayas-Santiago Astrid
Published: June 2019

In vivo tissue transparency in the visible light spectrum is beneficial for many research applications that use optical methods, whether it involves in vivo optical imaging of cells or their activity, or optical intervention to affect cells or their activity deep inside tissues, such as brain tissue. The classical view is that a tissue is transparent if it neither absorbs nor scatters light, and thus absorption and scattering are the key elements to be controlled to reach the necessary transparency. This review focuses on the latest genetic and chemical approaches for the decoloration of tissue pigments to reduce visible light absorption and the methods to reduce scattering in live tissues. We also discuss the possible molecules involved in transparency.
Identification of Pyrvinium, an Anthelmintic Drug, as a Novel Anti-Adipogenic Compound Based on the Gene Expression Microarray and Connectivity Map
Authors: Wang Zonggui , Dai Zhong , Luo Zhicong , Zuo Changqing
Published: June 2019

Obesity is a serious health problem, while the current anti-obesity drugs are not very effective. The Connectivity Map (C-Map), an in-silico drug screening approach based on gene expression profiles, has recently been indicated as a promising strategy for drug repositioning. In this study, we performed mRNA expression profile analysis using microarray technology and identified 435 differentially expressed genes (DEG) during adipogenesis in both C3H10T1/2 and 3T3-L1 cells. Then, DEG signature was uploaded into C-Map, and using pattern-matching methods we discovered that pyrvinium, a classical anthelminthic, is a novel anti-adipogenic differentiation agent. Pyrvinium suppressed adipogenic differentiation in a dose-dependent manner, as evidenced by Oil Red O staining and the mRNA levels of adipogenic markers. Furthermore, we identified that the inhibitory effect of pyrvinium was resulted primarily from the early stage of adipogenesis. Molecular studies showed that pyrvinium downregulated the expression of key transcription factors C/EBPa and PPARγ. The mRNA levels of notch target genes Hes1 and Hey1 were obviously reduced after pyrvinium treatment. Taken together, this study identified many differentially expressed genes involved in adipogenesis and demonstrated for the first time that pyrvinium is a novel anti-adipogenic compound for obesity therapy. Meanwhile, we provided a new strategy to explore potential anti-obesity drugs.
Synthesis and AChE Inhibitory Activity of Novel Thiazolylhydrazone Derivatives
Authors: Osmaniye Derya , Sağlık Begüm Nurpelin , Acar Çevik Ulviye , Levent Serkan , Kaya Çavuşoğlu Betül , Özkay Yusuf , Kaplancıklı Zafer Asım , Turan Gülhan
Published: June 2019

Alzheimer’s disease (AD) is the most common of the degenerative brain diseases and is described together with the impairment of cognitive function. Patients with AD lose the capability to code new memories, and life conditions are extremely difficult. The development of new drugs in this area continues at a great pace. A novel series of thiazole-piperazine hybrids, aimed against Alzheimer’s disease (AD), have been synthesized. The structure identification of synthesized compounds was elucidated by 1HNMR, 13C-NMR, and LCMSMS spectroscopic methods. The inhibitory potential of the synthesized compounds on cholinesterase enzymes was investigated. The compounds 3a, 3c and 3i showed significant inhibitory activity on the acetylcholinesterase (AChE) enzyme. On the other hand, none of the compounds showed significant inhibitory activity on the butyrylcholinesterase (BChE) enzyme. In addition to enzyme inhibition studies, enzyme kinetic studies were performed to observe the effects of the most active inhibitor compounds on the substrate–enzyme relationship. In addition to in vitro tests, docking studies also indicated that compound 3c potentially acts as a dual binding site AChE inhibitor.
2-Ketogluconate Kinase from Cupriavidus necator H16: Purification, Characterization, and Exploration of Its Substrate Specificity
Authors: Sánchez-Moreno Israel , Trachtmann Natalia , Ilhan Sibel , Hélaine Virgil , Lemaire Marielle , Guérard-Hélaine Christine , Sprenger Georg A.
Published: June 2019

We have cloned, overexpressed, purified, and characterized a 2-ketogluconate kinase (2-dehydrogluconokinase, EC 2.7.1.13) from Cupriavidus necator (Ralstonia eutropha) H16. Exploration of its substrate specificity revealed that three ketoacids (2-keto-3-deoxy-d-gluconate, 2-keto-d-gulonate, and 2-keto-3-deoxy-d-gulonate) with structures close to the natural substrate (2-keto-d-gluconate) were successfully phosphorylated at an efficiency lower than or comparable to 2-ketogluconate, as depicted by the measured kinetic constant values. Eleven aldo and keto monosaccharides of different chain lengths and stereochemistries were also assayed but not found to be substrates. 2-ketogluconate-6-phosphate was synthesized at a preparative scale and was fully characterized for the first time.
A Quantum Chemistry Approach Based on the Analogy with π-System in Polymers for a Rapid Estimation of the Resonance Wavelength of Nanoparticle Systems
Authors: De Giacomo Alessandro , Salajkova Zita , Dell’Aglio Marcella
Published: June 2019

In this paper, the Variational Method based on the Hückel Theory is applied to NPs chain and aggregate systems in order to estimate the energy of the plasmon and, in turn, the resonance wavelength shift, which is caused by the interaction of adjacent NPs. This method is based on the analogies of NPs dipole interactions and the π-system in molecules. Differently from the Hartree-Fock method that is a self-consistent model, in this approach, the input data that this method requires is the dimer energy shift with respect to single NPs. This enables us to acquire a simultaneous estimation of the wavefunctions of the NPs system as well as the expectation energy value of every kind of NPs system. The main advantage of this approach is the rapid response and ease of application to every kind of geometries and spacing from the linear chain to clusters, without the necessity of a time-consuming calculation. The results obtained with this model are closely aligned to related literature and open the way to further development of this methodology for investigating other properties of NPs systems.
Hydrogen Induced Etching Features of Wrinkled Graphene Domains
Authors: Li Qiongyu , Li Fang , Li You , Du Yongping , Shih Tien-Mo , Kan Erjun
Published: June 2019

Wrinkles are observed commonly in CVD (chemical vapor deposition)-grown graphene on Cu and hydrogen etching is of significant interest to understand the growth details, as well as a practical tool for fabricating functional graphene nanostructures. Here, we demonstrate a special hydrogen etching phenomenon of wrinkled graphene domains. We investigated the wrinkling of graphene domains under fast cooling conditions and the results indicated that wrinkles in the monolayer area formed more easily compared to the multilayer area (≥two layers), and the boundary of the multilayer area tended to be a high density wrinkle zone in those graphene domains, with a small portion of multilayer area in the center. Due to the site-selective adsorption of atomic hydrogen on wrinkled regions, the boundary of the multilayer area became a new initial point for the etching process, aside from the domain edge and random defect sites, as reported before, leading to the separation of the monolayer and multilayer area over time. A schematic model was drawn to illustrate how the etching of wrinkled graphene was generated and propagated. This work may provide valuable guidance for the design and growth of nanostructures based on wrinkled graphene.
Design of Morphology-Controllable ZnO Nanorods/Nanopariticles Composite for Enhanced Performance of Dye-Sensitized Solar Cells
Authors: Wang Dongting , Zhang Yuting , Su Meng , Xu Ting , Yang Haizhou , Bi Shiqing , Zhang Xianxi , Fang Yuzhen , Zhao Jinsheng
Published: June 2019

A facile one-pot approach was developed for the synthesis of ZnO nanorods (NRs)/nanoparticles (NPs) architectures with controllable morphologies. The concrete state of existence of NPs and NRs could rationally be controlled through reaction temperature manipulation, i.e., reactions occured at 120, 140, 160, and 180 °C without stirring resulted in orderly aligned NRs, disordered but connected NRs/NPs, and relatively dispersed NRs/NPs with different sizes and lengths, respectively. The as-obained ZnO nanostructures were then applied to construct photoanodes of dye-sensitized solar cells, and the thicknesses of the resultant films were controlled for performance optimization. Under an optimized condition (i.e., with a film thickness of 14.7 µm), the device fabricated with the material synthesized at 160 °C exhibited the highest conversion efficiency of 4.30% with an elevated current density of 14.50 mA·cm−2 and an open circuit voltage of 0.567 V. The enhanced performance could be attributed to the coordination effects of the significantly enhanced dye absorption capability arising from the introduced NPs and the intrinsic fast electron transport property of NRs as confirmed by electrochemical impedance spectroscopy (EIS) and ultraviolet–visible (UV−vis) absorption.
Dopant-Free Hole Transport Materials with a Long Alkyl Chain for Stable Perovskite Solar Cells
Authors: Wang Kai , Chen Haoran , Niu Tingting , Wang Shan , Guo Xiao , Wang Hong
Published: June 2019

Hole transport materials are indispensable to high efficiency perovskite solar cells. Two new hole transporting materials (HTMs), named 4,4′-(9-nonyl-9H-carbazole-3,6-diyl)bis (N,N-bis(4-methoxyphenyl)aniline) (CZTPA-1) and 4,4′-(9-methyl-9H-carbazole-3,6-diyl)bis (N,N-bis(4-methoxyphenyl)aniline)(CZTPA-2), were developed by different alkyl substitution methods. The two compounds, containing a carbazole core and triphenylamine (TPA) groups with different lengths of the alkyl chain, were designed and synthesized through a two-step synthesis approach. The power conversion efficiency (PCE) was found to be affected by the length of the alkyl chain, reaching 7% for CZTPA-1 and 11% for CZTPA-2. Furthermore, the CZTPA-2 still maintained 89.7% of its original performance after 400 h. The proposed results demonstrate the effect of carbon chain substituents on the efficiency of perovskite solar cells (PSCs).
Three-Dimensional Heterostructured Reduced Graphene Oxide-Hexagonal Boron Nitride-Stacking Material for Silicone Thermal Grease with Enhanced Thermally Conductive Properties
Authors: Liang Weijie , Ge Xin , Ge Jianfang , Li Tiehu , Zhao Tingkai , Chen Xunjun , Zhang Mingchang , Ji Jianye , Pang Xiaoyan , Liu Ruoling
Published: June 2019

The thermally conductive properties of silicone thermal grease enhanced by hexagonal boron nitride (hBN) nanosheets as a filler are relevant to the field of lightweight polymer-based thermal interface materials. However, the enhancements are restricted by the amount of hBN nanosheets added, owing to a dramatic increase in the viscosity of silicone thermal grease. To this end, a rational structural design of the filler is needed to ensure the viable development of the composite material. Using reduced graphene oxide (RGO) as substrate, three-dimensional (3D) heterostructured reduced graphene oxide-hexagonal boron nitride (RGO-hBN)-stacking material was constructed by self-assembly of hBN nanosheets on the surface of RGO with the assistance of binder for silicone thermal grease. Compared with hBN nanosheets, 3D RGO-hBN more effectively improves the thermally conductive properties of silicone thermal grease, which is attributed to the introduction of graphene and its phonon-matching structural characteristics. RGO-hBN/silicone thermal grease with lower viscosity exhibits higher thermal conductivity, lower thermal resistance and better thermal management capability than those of hBN/silicone thermal grease at the same filler content. It is feasible to develop polymer-based thermal interface materials with good thermal transport performance for heat removal of modern electronics utilising graphene-supported hBN as the filler at low loading levels.
Osteoblast Biocompatibility and Antibacterial Effects Using 2-Methacryloyloxyethyl Phosphocholine-Grafted Stainless-Steel Composite for Implant Applications
Authors: Chen Dave W. , Yu Hsin-Hsin , Luo Li-Jyuan , Rajesh Kumar Selvaraj , Chen Chien-Hao , Lin Tung-Yi , Lai Jui-Yang , Jessie Lue Shingjiang
Published: June 2019

Poor osteogenesis and bacterial infections lead to an implant failure, so the enhanced osteogenic and antimicrobial activity of the implantable device is of great importance in orthopedic applications. In this study, 2-methacryloyloxyethyl phosphocholine (MPC) was grafted onto 316L stainless steel (SS) using a facile photo-induced radical graft polymerization method via a benzophenone (BP) photo initiator. Atomic force microscopy (AFM) was employed to determine the nanoscale morphological changes on the surface. The grafted BP-MPC layer was estimated to be tens of nanometers thick. The SS-BP-MPC composite was more hydrophilic and smoother than the untreated and BP-treated SS samples. Staphylococcus aureus (S. aureus) bacteria binding onto the SS-BP-MPC composite film surface was significantly reduced compared with the pristine SS and SS-BP samples. Mouse pre-osteoblast (MC3T3-E1) cells showed good adhesion on the MPC-modified samples and better proliferation and metabolic activity (73% higher) than the pristine SS sample. Biological studies revealed that grafting MPC onto the SS substrate enhanced the antibacterial efficiency and also retained osteoblast biocompatibility. This proposed procedure is promising for use with other implant materials.
Extracting the Dynamic Magnetic Contrast in Time-Resolved X-Ray Transmission Microscopy
Authors: Schaffers Taddäus , Feggeler Thomas , Pile Santa , Meckenstock Ralf , Buchner Martin , Spoddig Detlef , Ney Verena , Farle Michael , Wende Heiko , Wintz Sebastian , Weigand Markus , Ohldag Hendrik , Ollefs Katharina , Ney Andreas
Published: June 2019

Using a time-resolved detection scheme in scanning transmission X-ray microscopy (STXM), we measured element resolved ferromagnetic resonance (FMR) at microwave frequencies up to 10 GHz and a spatial resolution down to 20 nm at two different synchrotrons. We present different methods to separate the contribution of the background from the dynamic magnetic contrast based on the X-ray magnetic circular dichroism (XMCD) effect. The relative phase between the GHz microwave excitation and the X-ray pulses generated by the synchrotron, as well as the opening angle of the precession at FMR can be quantified. A detailed analysis for homogeneous and inhomogeneous magnetic excitations demonstrates that the dynamic contrast indeed behaves as the usual XMCD effect. The dynamic magnetic contrast in time-resolved STXM has the potential be a powerful tool to study the linear and nonlinear, magnetic excitations in magnetic micro- and nano-structures with unique spatial-temporal resolution in combination with element selectivity.
A Nationwide Survey of the Attitudes toward the Use of Dietary Supplements among Japanese High-School Students
Authors: Nishijima Chiharu , Kobayashi Etsuko , Sato Yoko , Chiba Tsuyoshi
Published: June 2019

We previously studied the prevalence of dietary supplement use in Japanese high-school students by conducting a study on mothers. However, there is often a discrepancy between mothers’ understanding and children’s attitudes. Thus, we conducted an internet survey of high-school students to clarify their attitudes toward the use of dietary supplements. An invitation to the internet survey was e-mailed to registrants of a research company aged 15 to 18 years. A total of 1031 students (276 male, 755 female) answered the questionnaire on a first come, first served basis. The participants were classified according to the purchasers of their supplements: students who purchased supplements themselves were defined as active users, and others were defined as passive users. The prevalence of dietary supplement use was 30.8% in males and 26.7% in females. Among the users, 42.4% of males and 43.8% of females were active users. Males used supplements for health regardless of active or passive use. However, in females, more active users (40.9%) used supplements for weight loss than passive users (20.4%); the corresponding prevalence was 2.3% in our previous report on mothers’ understanding of their daughters. The most frequently used source of information for active users was the internet, whereas for passive users it was family. The frequency of adverse events was 9.4% in males and 14.4% in females, with gastrointestinal symptoms being the most commonly experienced events. Our results suggest that dietary education, including healthy eating and the appropriate use of dietary supplements, should be provided to high-school students.
Anaemia and Its Relation to Demographic, Socio-economic and Anthropometric Factors in Rural Primary School Children in Hai Phong City, Vietnam
Authors: Hoang Ngan T.D. , Orellana Liliana , Le Tuyen D. , Gibson Rosalind S. , Worsley Anthony , Sinclair Andrew J. , Hoang Nghien T.T. , Szymlek-Gay Ewa A.
Published: June 2019

Little is known about the prevalence of anaemia and associated factors in school children in Vietnam. In this cross-sectional study, we aimed to determine the prevalence of anaemia and its subtypes, and the associations of types of anaemia with demographic, socio-economic and anthropometric factors among 6–9-year-old primary school children in rural areas of Hai Phong City, Vietnam. Haemoglobin (Hb) and mean corpuscular volume (MCV) were measured, and demographic, socio-economic and anthropometric data were collected in 893 children from eight primary schools. The prevalence of anaemia (Hb < 115 g/L) was 12.9% (95% CI: 8.1%, 19.9%), microcytic anaemia (Hb < 115 g/L and MCV < 80 fL) was 7.9% (95% CI: 5.3%, 11.6%) and normocytic anaemia (Hb < 115 g/L and MCV 80–90 fL) was 5.3% (95% CI: 2.9%, 9.5%). No child presented with macrocytic anaemia (Hb < 115 g/L and MCV > 90 fL). Children who were underweight, wasted, or in anthropometric failure (either underweight, stunted or wasted) were more likely to be anaemic (all p ≤ 0.004), and specifically, to have normocytic anaemia (all p ≤ 0.006), than those who were not underweight, wasted or in anthropometric failure. Stunted children were more likely to be anaemic (p = 0.018) than those who were not stunted. Overweight/obese children were less likely to be anaemic (p = 0.026) or have normocytic anaemia (p = 0.038) compared with children who were not overweight/obese. No anthropometric status indicator was associated with the risk of microcytic anaemia. No demographic or socio-economic factor was associated with any type of anaemia. Anaemia remains a public health issue in rural areas in Hai Phong City, Vietnam, and future approaches for its prevention and control should target undernourished primary school children.
GPP (Composition of Ganoderma lucidum Poly-saccharides and Polyporus umbellatus Poly-saccharides) Enhances Innate Immune Function in Mice
Authors: Huang Qing , Li Liyuan , Chen Huiling , Liu Qingfei , Wang Zhao
Published: June 2019

Modern research has found that Ganoderma lucidum polysaccharides (GLP) and Polyporus umbellatus polysaccharides (PUP) mainly exhibit immunoregulation. However, the immune function of a polysaccharide composition consisting of GLP and PUP has not been studied. In this study, we developed a polysaccharide composition consisting of GLP and PUP in a ratio of 3:1 (named GPP). The immunoregulation of GPP was detected in RAW264.7 macrophages. Then, the acute oral toxicity of GPP and the effect of GPP on immunoregulation in mice was detected. The results showed that GPP enhanced the function of macrophage RAW264.7 cells through improving phagocytic ability, nitric oxide (NO) production and the mRNA expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)-α. GPP belonged to the non-toxic grade in mice. Moreover, GPP significantly improved macrophage phagocytic function and the activity of natural killer (NK) cells after being administered to mice at a dose of 0, 3.6, 120, 360 mg/kg body weight (mg/kg BW) orally for 30 days. Taken together, these findings suggested that GPP moderately regulated immune function in mice, which contributes to the further development and utilization of GLP and PUP in immune function.
Plasticiser-Free 3D Printed Hydrophilic Matrices: Quantitative 3D Surface Texture, Mechanical, Swelling, Erosion, Drug Release and Pharmacokinetic Studies
Authors: Khizer Zara , Akram Muhammad , Sarfraz Rai , Nirwan Jorabar , Farhaj Samia , Yousaf Maria , Hussain Tariq , Lou Shan , Timmins Peter , Conway Barbara , Ghori Muhammad
Published: June 2019

Hydroxypropyl methyl cellulose, HPMC, a hydrophilic polymer, is widely used for the development of extended release hydrophilic matrices and it is also considered as a good contender for the fabrication of 3D printing of matrix tablets. It is often combined with plasticisers to enable extrusion. The aim of the current project was to develop plasticizer-free 3D printed hydrophilic matrices using drug loaded filaments prepared via HME to achieve an in vitro (swelling, erosion and drug release) and in vivo (drug absorption) performance which is analogous to hydrophilic matrix tablets developed through conventional approaches. Additionally, the morphology of the printed tablets was studied using quantitative 3D surface texture studies and the porosity calculated. Filaments were produced successfully and used to produce matrix tablets with acceptable drug loading (95–105%), mechanical and surface texture properties regardless of the employed HPMC grade. The viscosity of HPMC had a discernible impact on the swelling, erosion, HPMC dissolution, drug release and pharmacokinetic findings. The highest viscosity grade (K100M) results in higher degree of swelling, decreased HPMC dissolution, low matrix erosion, decreased drug release and extended drug absorption profile. Overall, this study demonstrated that the drug loaded (glipizide) filaments and matrix tablets of medium to high viscosity grades of HPMC, without the aid of plasticisers, can be successfully prepared. Furthermore, the in vitro and in vivo studies have revealed the successful fabrication of extended release matrices.