bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly-Stable Li4Ti5O12 Anodes Obtained by Atomic-Layer-Deposited Al2O3
Authors: Yoon Jae Kook , Nam Seunghoon , Shim Hyung Cheoul , Park Kunwoo , Yoon Taeho , Park Hyung Sang , Hyun Seungmin
Published: May 2018

LTO (Li4Ti5O12) has been highlighted as anode material for next-generation lithium ion secondary batteries due to advantages such as a high rate capability, excellent cyclic performance, and safety. However, the generation of gases from undesired reactions between the electrode surface and the electrolyte has restricted the application of LTO as a negative electrode in Li-ion batteries in electric vehicles (EVs) and energy storage systems (ESS). As the generation of gases from LTO tends to be accelerated at high temperatures (40–60 °C), the thermal stability of LTO should be maintained during battery discharge, especially in EVs. To overcome these technical limitations, a thin layer of Al2O3 (~2 nm thickness) was deposited on the LTO electrode surface by atomic layer deposition (ALD), and an electrochemical charge-discharge cycle test was performed at 60 °C. The capacity retention after 500 cycles clearly shows that Al2O3-coated LTO outperforms the uncoated one, with a discharge capacity retention of ~98%. TEM and XPS analyses indicate that the surface reactions of Al2O3-coated LTO are suppressed, while uncoated LTO undergoes the (111) to (222) phase transformation, as previously reported in the literature.
Facile Synthesis of Magnetic Photocatalyst Ag/BiVO4/Mn1−xZnxFe2O4 and Its Highly Visible-Light-Driven Photocatalytic Activity
Authors: Xie Taiping , Li Hui , Liu Chenglun , Xu Longjun
Published: May 2018

Ag/BiVO4/Mn1−xZnxFe2O4 was synthesized with a dip-calcination in situ synthesis method. This work was hoped to provide a simple method to synthesis three-phase composite. The phase structure, optical properties and magnetic feature were confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometer (XPS), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectrophotometer (UV-vis DRS), and vibrating sample magnetometer (VSM). The photocatalytic activity was investigated by Rhodamine B (RhB) photo-degradation under visible light irradiation. The photo-degradation rate of RhB was 94.0~96.0% after only 60 min photocatalytic reaction under visible light irradiation, revealing that it had an excellent visible-light-induced photocatalytic activity. In the fifth recycle, the degradation rate of Ag/BiVO4/Mn1−xZnxFe2O4 still reached to 94.0%. Free radical tunnel experiments confirmed the dominant role of •O2− in the photocatalytic process for Ag/BiVO4/Mn1−xZnxFe2O4. Most importantly, the mechanism that multifunction Ag could enhance photocatalytic activity was explained in detail.
Microstructure Evolution and Mechanical Behavior of 2219 Aluminum Alloys Additively Fabricated by the Cold Metal Transfer Process
Authors: Fang Xuewei , Zhang Lijuan , Li Hui , Li Chaolong , Huang Ke , Lu Bingheng
Published: May 2018

In this research, four different welding arc modes including conventional cold metal transfer (CMT), CMT-Pulse (CMT-P), CMT-Advanced (CMT-ADV), and CMT pulse advanced (CMT-PADV) were used to deposit 2219-Al wire. The effects of different arc modes on porosity, pore size distribution, microstructure evolution, and mechanical properties were thoroughly investigated. The statistical analysis of the porosity and its size distribution indicated that the CMT-PADV process gave the smallest pore area percentage and pore aspect ratio, and had almost no larger pores. The results from optical microscopy, scanning electron microscopy, and fractographic morphology proved that uniform and fine equiaxed grains, evenly distributed Al2Cu second phase particles were formed during the CMT-PADV process. Furthermore, the X-ray diffraction test ascertained that the CMT-PADV sample had the smallest lattice parameter and the highest solute Cu content. Besides, the tensile strength could reach 283 MPa, the data scattering was the smallest, and the strength scattering of the sample in the horizontal direction was the shortest. In addition, the strength properties were nearly isotropic, with only 5 MPa difference in the vertical and horizontal directions. The above mentioned results indicated that the mechanical properties of 2219 aluminum alloy was improved using the CMT-PADV arc mode.
Effect of Babassu Natural Filler on PBAT/PHB Biodegradable Blends: An Investigation of Thermal, Mechanical, and Morphological Behavior
Authors: Beber Vinicius , De Barros Silvio , Banea Mariana , Brede Markus , De Carvalho Laura , Hoffmann Ron , Costa Anna , Bezerra Elieber , Silva Ingridy , Haag Katharina , Koschek Katharina , Wellen Renate
Published: May 2018

Blending of biodegradable polymers in combination with low-price organic fillers has proven to be a suitable approach to produce cost-effective composites in order to address pollution issues and develop products with superior mechanical properties. In the present research work PBAT/PHB/Babassu composites with 25, 50, and 75% of each polymer and 20% of Babassu were produced by melting extrusion. Their thermal, mechanical, and morphological behavior was investigated by differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM). Blending PBAT with PHB inhibited the crystallization of both polymers whereas adding Babassu did not significantly change their melting behaviour. Incorporation of Babassu reduced the tensile strength of its respective blends between 4.8 and 32.3%, and elongation at break between 26.0 and 66.3%. PBAT as highly ductile and low crystalline polymer may be seen as a crystallization tool control for PHB as well as a plasticizer to PBAT/PHB blends and PBAT/PHB/Babassu composites. As PBAT content increases: (i) elongation at break increases and (ii) surface fracture becomes more refined indicating the presence of more energy dissipation mechanisms. As PBAT/PHB/Babassu composites are biodegradable, environmental friendly, and cost effective, products based on these compounds have a great potential since their mechanical properties such as ductility, stiffness, and tensile strength are still suitable for several applications even at lower temperatures (−40 °C).
Ion Doping Effects on the Lattice Distortion and Interlayer Mismatch of Aurivillius-Type Bismuth Titanate Compounds
Authors: Chen Yu , Xu Jiageng , Xie Shaoxiong , Tan Zhi , Nie Rui , Guan Zhongwei , Wang Qingyuan , Zhu Jianguo
Published: May 2018

Taking Bismuth Titanate (Bi4Ti3O12) as a Aurivillius-type compound with m = 3 for example, the ion (W6+/Cr3+) doping effect on the lattice distortion and interlayer mismatch of Bi4Ti3O12 structure were investigated by stress analysis, based on an elastic model. Since oxygen-octahedron rotates in the ab-plane, and inclines away from the c-axis, a lattice model for describing the status change of oxygen-octahedron was built according to the substituting mechanism of W6+/Cr3+ for Ti4+, which was used to investigate the variation of orthorhombic distortion degree (a/b) of Bi4Ti3O12 with the doping content. The analysis shows that the incorporation of W6+/Cr3+ into Bi4Ti3O12 tends to relieve the distortion of pseudo-perovskite layer, which also helps it to become more stiff. Since the bismuth-oxide layer expands while the pseudo-perovskite layer tightens, an analytic model for the plane stress distribution in the crystal lattice of Bi4Ti3O12 was developed from the constitutive relationship of alternating layer structure. The calculations reveal that the structural mismatch of Bi4Ti3O12 is constrained in the ab-plane of a unit cell, since both the interlayer mismatch degree and the total strain energy vary with the doping content in a similar trend to the lattice parameters of ab-plane.
A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD) Method
Authors: Manawi Yehia M. , Ihsanullah  , Samara Ayman , Al-Ansari Tareq , Atieh Muataz A.
Published: May 2018

Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD) method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, carbide-derived carbon (CDC), carbon nano-onion (CNO) and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research.
In Situ Synthesis of Al-Based MMCs Reinforced with AlN by Mechanical Alloying under NH3 Gas
Authors: Caballero E. S. , Cuevas F. G. , Ternero F. , Astacio R. , Montes J. M. , Cintas J.
Published: May 2018

Aluminum matrix composites (AMCs) reinforced by aluminum nitride were prepared by mechanical alloying followed by a simple press and sintering method. Milling began under vacuum and after a period of between 1 and 4 h, NH3 gas flow (1 cm3/s) was incorporated until the total milling time of 5 h was reached. Results show that in addition to the strain hardening taking place during mechanical alloying, NH3 plays an additional role in powder hardening. Thereby, the properties of the sintered compacts are strongly influenced by the amount of N incorporated into the powders during milling and the subsequent formation of AlN during the consolidation process. The obtained AMC reaches tensile strengths as high as 459 MPa and hardness much higher than that of the as-received aluminum compact.
Electrical Performance and Reliability Improvement of Amorphous-Indium-Gallium-Zinc-Oxide Thin-Film Transistors with HfO2 Gate Dielectrics by CF4 Plasma Treatment
Authors: Fan Ching-Lin , Tseng Fan-Ping , Tseng Chiao-Yuan
Published: May 2018

In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a HfO2 gate insulator and CF4 plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO2 gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm2/V∙s (without treatment) to 54.6 cm2/V∙s (with CF4 plasma treatment), which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density. In addition, the reliability of the a-IGZO TFT with HfO2 gate dielectric has also been improved by the CF4 plasma treatment. By applying the CF4 plasma treatment to the a-IGZO TFT, the hysteresis effect of the device has been improved and the device’s immunity against moisture from the ambient atmosphere has been enhanced. It is believed that the CF4 plasma treatment not only significantly improves the electrical performance of a-IGZO TFT with HfO2 gate dielectric, but also enhances the device’s reliability.
Combined Effects of Set Retarders and Polymer Powder on the Properties of Calcium Sulfoaluminate Blended Cement Systems
Authors: Gwon Seongwoo , Jang Seung Yup , Shin Myoungsu
Published: May 2018

This study investigates the effects of set retarders on the properties of polymer-modified calcium sulfoaluminate (CSA) and Portland cement blend systems at early and long-term ages. The fast setting of the cement blend systems is typically adjusted by using retarders to ensure an adequate workability. However, how the addition of retarders influences the age-dependent characteristics of the cement blend systems was rarely investigated. This study particularly examines the effects of retarders on the microstructure and strength development of polymer-modified CSA and Portland cement blend pastes and mortars from 2 h to 90 days. The macro- and microstructural properties are characterized by compression testing, powder X-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy with energy dispersive spectroscopy. The test results reveal that the use of retarders delayed the strength development of the cement blend systems at the very early age by hindering the production of ettringite, which was cumulative to the delaying effect of polymer, but it increased the ultimate strength by creating denser and finer pore structures with the evolution of hydration products.
Effect of Ultrasonic Vibration on Mechanical Properties of 3D Printing Non-Crystalline and Semi-Crystalline Polymers
Authors: Li Guiwei , Zhao Ji , Wu Wenzheng , Jiang Jili , Wang Bofan , Jiang Hao , Fuh Jerry Ying Hsi
Published: May 2018

Fused deposition modeling 3D printing has become the most widely used additive manufacturing technology because of its low manufacturing cost and simple manufacturing process. However, the mechanical properties of the 3D printing parts are not satisfactory. Certain pressure and ultrasonic vibration were applied to 3D printed samples to study the effect on the mechanical properties of 3D printed non-crystalline and semi-crystalline polymers. The tensile strength of the semi-crystalline polymer polylactic acid was increased by 22.83% and the bending strength was increased by 49.05%, which were almost twice the percentage increase in the tensile strength and five times the percentage increase in the bending strength of the non-crystalline polymer acrylonitrile butadiene styrene with ultrasonic strengthening. The dynamic mechanical properties of the non-crystalline and semi-crystalline polymers were both improved after ultrasonic enhancement. Employing ultrasonic energy can significantly improve the mechanical properties of samples without modifying the 3D printed material or adjusting the forming process parameters.
One-Dimensional and Two-Dimensional Analytical Solutions for Functionally Graded Beams with Different Moduli in Tension and Compression
Authors: Li Xue , Sun Jun-yi , Dong Jiao , He Xiao-ting
Published: May 2018

The material considered in this study not only has a functionally graded characteristic but also exhibits different tensile and compressive moduli of elasticity. One-dimensional and two-dimensional mechanical models for a functionally graded beam with a bimodular effect were established first. By taking the grade function as an exponential expression, the analytical solutions of a bimodular functionally graded beam under pure bending and lateral-force bending were obtained. The regression from a two-dimensional solution to a one-dimensional solution is verified. The physical quantities in a bimodular functionally graded beam are compared with their counterparts in a classical problem and a functionally graded beam without a bimodular effect. The validity of the plane section assumption under pure bending and lateral-force bending is analyzed. Three typical cases that the tensile modulus is greater than, equal to, or less than the compressive modulus are discussed. The result indicates that due to the introduction of the bimodular functionally graded effect of the materials, the maximum tensile and compressive bending stresses may not take place at the bottom and top of the beam. The real location at which the maximum bending stress takes place is determined via the extreme condition for the analytical solution.
The Construction of a Model-Robust IV-Optimal Mixture Designs Using a Genetic Algorithm
Authors: Limmun Wanida , Chomtee Boonorm , Borkowski John J.
Published: May 2018

Among the numerous alphabetical optimality criteria is the IV-criterion that is focused on prediction variance. We propose a new criterion, called the weighted IV-optimality. It is similar to IV-optimality, because the researcher must first specify a model. However, unlike IV-optimality, a suite of “reduced” models is also proposed if the original model is misspecified via over-parameterization. In this research, weighted IV-optimality is applied to mixture experiments with a set of prior weights assigned to the potential mixture models of interest. To address the issue of implementation, a genetic algorithm was developed to generate weighted IV-optimal mixture designs that are robust across multiple models. In our examples, we assign models with p parameters to have equal weights, but weights will vary based on varying p. Fraction-of-design-space (FDS) plots are used to compare the performance of an experimental design in terms of the prediction variance properties. An illustrating example is presented. The result shows that the GA-generated designs studied are robust across a set of potential mixture models.
Anticancer Activity of Euplotin C, Isolated from the Marine Ciliate Euplotes crassus, Against Human Melanoma Cells
Authors: Carpi Sara , Polini Beatrice , Poli Giulio , Alcantara Barata Gabriela , Fogli Stefano , Romanini Antonella , Tuccinardi Tiziano , Guella Graziano , Frontini Francesco Paolo , Nieri Paola , Di Giuseppe Graziano
Published: May 2018

Cutaneous melanoma is the most serious type of skin cancer, so new cytotoxic weapons against novel targets in melanoma are of great interest. Euplotin C (EC), a cytotoxic secondary metabolite of the marine ciliate Euplotes crassus, was evaluated in the present study on human cutaneous melanoma cells to explore its anti-melanoma activity and to gain more insight into its mechanism of action. EC exerted a marked cytotoxic effect against three different human melanoma cell lines (A375, 501Mel and MeWo) with a potency about 30-fold higher than that observed in non-cancer cells (HDFa cells). A pro-apoptotic activity and a decrease in melanoma cell migration by EC were also observed. At the molecular level, the inhibition of the Erk and Akt pathways, which control many aspects of melanoma aggressiveness, was shown. EC cytotoxicity was antagonized by dantrolene, a ryanodine receptor (RyR) antagonist, in a concentration-dependent manner. A role of RyR as a direct target of EC was also suggested by molecular modelling studies. In conclusion, our data provide the first evidence of the anti-melanoma activity of EC, suggesting it may be a promising new scaffold for the development of selective activators of RyR to be used for the treatment of melanoma and other cancer types.
Precursor-Directed Generation of Indolocarbazoles with Topoisomerase IIα Inhibitory Activity
Authors: Wang Cong , Monger Adeep , Wang Liping , Fu Peng , Piyachaturawat Pawinee , Chairoungdua Arthit , Zhu Weiming
Published: May 2018

One new indolocarbazole, 3-hydroxy-K252d (3), together with the recently reported 3-hydroxyholyrine A (1) and 3′-N-acetyl-3-hydroxyholyrine A (2), were obtained by feeding a culture of the marine-derived Streptomyces strain OUCMDZ-3118 with 5-hydroxy-l-tryptophan. Their structures were elucidated on the basis of spectroscopic analysis. Compound 1 potently induced apoptosis of gastric cancer cells by inhibiting topoisomerase IIα enzyme activity and reducing the expression of antiapoptosis protein level. Compound 3 displayed moderate cytotoxicity against the A549 and MCF-7 cell lines with IC50 values of 1.2 ± 0.05 μM, 1.6 ± 0.09 μM, respectively.
Hydrogen Evolution Reaction Property of Molybdenum Disulfide/Nickel Phosphide Hybrids in Alkaline Solution
Authors: Yang Fan , Kang Ning , Yan Jiayun , Wang Xiuli , He Jun , Huo Siyue , Song Laizhou
Published: May 2018

The hydrogen evolution reaction (HER) property of molybdenum disulfide (MoS2) is undesirable because of the insufficient active edge sites and the poor conductivity. To enhance HER performance of MoS2, nickel phosphide (Ni2P) was combined with this catalyst and three MoS2/Ni2P hybrids (38 wt % Ni2P addition for MoS2/Ni2P-38, 50 wt % Ni2P addition for MoS2/Ni2P-50, and 58 wt % Ni2P addition for MoS2/Ni2P-58) were fabricated via a hydrothermal synthesis process. Morphologies, crystallinities, chemical components, specific surface areas, and HER properties of the fabricated MoS2/Ni2P samples in an alkaline electrolyte were characterized and tested. In addition, the insight into the HER properties of as-prepared catalysts were revealed by the density functional theory (DFT) calculation. Additionally, the stabilities of pure MoS2, Ni2P, and MoS2/Ni2P-50 samples were evaluated. The results show that the addition of Ni2P can enhance the HER property of the MoS2 catalyst. Although HER properties of the above-mentioned three MoS2/Ni2P hybrids are inferior to that of pure Ni2P, they are much higher than that of MoS2. Among as-prepared three hybrids, MoS2/Ni2P-50 exhibits the best HER performance, which may be due to its uniform morphology, large specific surface area, and excellent stability. The MoS2/Ni2P-50 hybrid shows a high cathodic current density (70 mA/cm2 at −0.48 V), small Tafel slope (~58 mV/decade), and a low charge transfer resistance (0.83 kΩ·cm2).
Determination of the Critical Stress Associated with Dynamic Phase Transformation in Steels by Means of Free Energy Method
Authors: Aranas Clodualdo , Rodrigues Samuel , Fall Ameth , Jahazi Mohammad , Jonas John
Published: May 2018

The double differentiation method overestimates the critical stress associated with the initiation of dynamic transformation (DT) because significant amounts of the dynamic phase must be present in order for its effect on the work hardening rate to be detectable. In this work, an alternative method (referred to here as the free energy method) is presented based on the thermodynamic condition that the driving force is equal to the total energy obstacle during the exact moment of transformation. The driving force is defined as the difference between the DT critical stress (measured in the single-phase austenite region) and the yield stress of the fresh ferrite that takes its place. On the other hand, the energy obstacle consists of the free energy difference between austenite and ferrite, and the work of shear accommodation and dilatation associated with the phase transformation. Here, the DT critical stresses in a C-Mn steel were calculated using the free energy method at temperatures ranging from 870 °C to 1070 °C. The results show that the calculated critical stress using the present approach appears to be more accurate than the values measured by the double differentiation method.
Electrodeposition of Fe-C Alloys from Citrate Baths: Structure, Mechanical Properties, and Thermal Stability
Authors: Müller Timo , Grimwood Joseph , Bachmaier Andrea , Pippan Reinhard
Published: May 2018

A new citrate-based electrolyte is proposed for the electrodeposition of thick Fe-C films. The structure and properties of the deposits are compared to those from another electrolyte previously reported in the literature. Both consist of a nanocrystalline single-phase structure with a grain size of 20 nm, which results in a hardness of up to 660 HV. Due to its higher growth rate, the new electrolyte is a promising candidate for the deposition of thick films. However, the codeposition of oxygen causes embrittlement, limiting the application of the deposits from both the new and the known electrolyte. On the other hand, the codeposited carbon and oxygen provide considerable thermal stability and even a hardening capacity upon annealing. The results are compared and discussed with respect to the previous investigations of electrodeposited Fe-C alloys.
Genetic Optimization Algorithm for Metabolic Engineering Revisited
Authors: Alter Tobias B. , Blank Lars M. , Ebert Birgitta E.
Published: May 2018

To date, several independent methods and algorithms exist for exploiting constraint-based stoichiometric models to find metabolic engineering strategies that optimize microbial production performance. Optimization procedures based on metaheuristics facilitate a straightforward adaption and expansion of engineering objectives, as well as fitness functions, while being particularly suited for solving problems of high complexity. With the increasing interest in multi-scale models and a need for solving advanced engineering problems, we strive to advance genetic algorithms, which stand out due to their intuitive optimization principles and the proven usefulness in this field of research. A drawback of genetic algorithms is that premature convergence to sub-optimal solutions easily occurs if the optimization parameters are not adapted to the specific problem. Here, we conducted comprehensive parameter sensitivity analyses to study their impact on finding optimal strain designs. We further demonstrate the capability of genetic algorithms to simultaneously handle (i) multiple, non-linear engineering objectives; (ii) the identification of gene target-sets according to logical gene-protein-reaction associations; (iii) minimization of the number of network perturbations; and (iv) the insertion of non-native reactions, while employing genome-scale metabolic models. This framework adds a level of sophistication in terms of strain design robustness, which is exemplarily tested on succinate overproduction in Escherichia coli.
Micromachined Planar Supercapacitor with Interdigital Buckypaper Electrodes
Authors: Chen Yun-Ting , Ma Cheng-Wen , Chang Chia-Ming , Yang Yao-Joe
Published: May 2018

In this work, a flexible micro-supercapacitor with interdigital planar buckypaper electrodes is presented. A simple fabrication process involving vacuum filtration method and SU-8 molding techniques is proposed to fabricate in-plane interdigital buckypaper electrodes on a membrane filter substrate. The proposed process exhibits excellent flexibility for future integration of the micro-supercapacitors (micro-SC) with other electronic components. The device’s maximum specific capacitance measured using cyclic voltammetry was 107.27 mF/cm2 at a scan rate of 20 mV/s. The electrochemical stability was investigated by measuring the performance of charge-discharge at different discharge rates. Devices with different buckypaper electrode thicknesses were also fabricated and measured. The specific capacitance of the proposed device increased linearly with the buckypaper electrode thickness. The measured leakage current was approximately 9.95 µA after 3600 s. The device exhibited high cycle stability, with 96.59% specific capacitance retention after 1000 cycles. A Nyquist plot of the micro-SC was also obtained by measuring the impedances with frequencies from 1 Hz to 50 kHz; it indicated that the equivalent series resistance value was approximately 18 Ω.
Manipulation of Biological Cells Using a Robot-Aided Optical Tweezers System
Authors: Xie Mingyang , Shakoor Adnan , Wu Changcheng
Published: May 2018

This article reviews the autonomous manipulation strategies of biological cells utilizing optical tweezers, mainly including optical direct and indirect manipulation strategies. The typical and latest achievements in the optical manipulation of cells are presented, and the existing challenges for autonomous optical manipulation of biological cells are also introduced. Moreover, the integrations of optical tweezers with other manipulation tools are presented, which broadens the applications of optical tweezers in the biomedical manipulation areas and will also foster new developments in cell-based physiology and pathology studies, such as cell migration, single cell surgery, and preimplantation genetic diagnosis (PGD).
The Antimicrobial Activity of Annona emarginata (Schltdl.) H. Rainer and Most Active Isolated Compounds against Clinically Important Bacteria
Authors: Dolab Juan G. , Lima Beatriz , Spaczynska Ewelina , Kos Jiri , Cano Natividad H. , Feresin Gabriela , Tapia Alejandro , Garibotto Francisco , Petenatti Elisa , Olivella Monica , Musiol Robert , Jampilek Josef , Enriz Ricardo D.
Published: May 2018

Annona emarginata (Schltdl.) H. Rainer, commonly known as “arachichú”, “araticú”, “aratigú”, and “yerba mora”, is a plant that grows in Argentina. Infusions and decoctions are used in folk medicine as a gargle against throat pain and for calming toothache; another way to use the plant for these purposes is chewing its leaves. Extracts from bark, flowers, leaves, and fruits from A. emarginata were subjected to antibacterial assays against a panel of Gram (+) and Gram (−) pathogenic bacteria according to Clinical and Laboratory Standards Institute protocols. Extracts from the stem bark and leaves showed moderate activity against the bacteria tested with values between 250–1000 µg/mL. Regarding flower extracts, less polar extracts (hexane, dichloromethane) showed very strong antibacterial activity against methicillin-sensitive Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus ATCC 43300 with values between 16–125 µg/mL. Additionally, hexane extract showed activity against Klebsiella pneumoniae (MIC = 250 µg/mL). The global methanolic extract of the fruits (MeOHGEF) was also active against the three strains mentioned above, with MICs values 250–500 µg/mL. Bioassay-guided fractionation of MeOHGEF led to the isolation of a new main compound—(R)-2-(4-methylcyclohex-3-en-1-yl)propan-2-yl (E)-3-(4-hydroxyphenyl)acrylate (1). The structure and relative configurations have been determined by means of 1D and 2D NMR techniques, including COSY, HMQC, HMBC, and NOESY correlations. Compound 1 showed strong antimicrobial activity against all Gram (+) species tested (MICs = 3.12–6.25 µg/mL). In addition, the synthesis and antibacterial activity of some compounds structurally related to compound 1 (including four new compounds) are reported. A SAR study for these compounds was performed based on the results obtained by using molecular calculations.
Antioxidant Activity and Hepatoprotective Potential of Quercetin 7-Rhamnoside In Vitro and In Vivo
Authors: Huang Zhi-Qiang , Chen Pan , Su Wei-Wei , Wang Yong-Gang , Wu Hao , Peng Wei , Li Pei-Bo
Published: May 2018

Hypericum japonicum is traditionally used as a folk medicine to treat cholestasis and hepatitis. Quercetin 7-rhamnoside (Q7R) is one of the main flavonoid components of Hypericum japonicum and has been rarely studied. The aim of the present study was to evaluate the antioxidant activity and hepatoprotective potential of Q7R. In the in vitro experiments, DPPH, ABTS and ferric reducing antioxidant power (FRAP) assays were first performed to assess the antioxidant properties of Q7R, and then a H2O2-induced oxidative damage cellular model was used to determine the cytoprotective and antioxidant properties of Q7R in human liver L-02 cells. In the in vivo experiment, the hepatoprotective activity of Q7R was evaluated by carbon tetrachloride (CCl4)-induced liver damage model in mice. The results of the three in vitro assays (DPPH, ABTS and FRAP) demonstrated that Q7R significantly exhibited antioxidant activity. The cell experiment results showed that Q7R possessed cytoprotective and antioxidant effects on H2O2-treated L-02 cells. In the in vivo experiments, Q7R suppressed the up-regulation of serum activities of ALT, AST, LDH and triglyceride (TG) levels with dose-dependency. Q7R down-regulated the production of MDA and increased the hepatic GSH content and antioxidant enzymes CAT activities. Hepatic morphological analysis was also performed to confirm the biochemical changes. In summary, these results suggested that Q7R could be considered as a potential source of natural antioxidants, and may become a promising candidate for the treatment of liver injury in the future.
Antioxidant and ACE Inhibitory Activity of Enzymatic Hydrolysates from Ruditapes philippinarum
Authors: Yu Yue , Fan Fengjiao , Wu Di , Yu Cuiping , Wang Zhenyu , Du Ming
Published: May 2018

Ruditapes philippinarum proteins were hydrolyzed by trypsin, neutrase, and pepsin. The antioxidant activities and ACE inhibitory activity of hydrolysates were analyzed and the antioxidant activities were related to their molecular weight distribution and amino acid compositions. Results indicated the hydrolysis of proteins led to an increase in small peptides and free amino acids. The antioxidant activities of Ruditapes philippinarum hydrolysates against DPPH radical scavenging, inhibition on linoleic acid peroxidation, and reducing power showed that the neutrase hydrolysate exhibited the strongest antioxidant activity. In addition, an ACE inhibition assay revealed that the pepsin hydrolysate had the highest ACE inhibitory ability. Ruditapes philippinarum protein hydrolysates could be a promising source of natural antioxidant and ACE inhibitory.
Peritoneal Carcinomatosis Targeting with Tumor Homing Peptides
Authors: Simón-Gracia Lorena , Hunt Hedi , Teesalu Tambet
Published: May 2018

Over recent decades multiple therapeutic approaches have been explored for improved management of peritoneally disseminated malignancies—a grim condition known as peritoneal carcinomatosis (PC). Intraperitoneal (IP) administration can be used to achieve elevated local concentration and extended half-life of the drugs in the peritoneal cavity to improve their anticancer efficacy. However, IP-administered chemotherapeutics have a short residence time in the IP space, and are not tumor selective. An increasing body of work suggests that functionalization of drugs and nanoparticles with targeting peptides increases their peritoneal retention and provides a robust and specific tumor binding and penetration that translates into improved therapeutic response. Here we review the progress in affinity targeting of intraperitoneal anticancer compounds, imaging agents and nanoparticles with tumor-homing peptides. We review classes of tumor-homing peptides relevant for PC targeting, payloads for peptide-guided precision delivery, applications for targeted compounds, and the effects of nanoformulation of drugs and imaging agents on affinity-based tumor delivery.
Structure-Activity Relationships Based on 3D-QSAR CoMFA/CoMSIA and Design of Aryloxypropanol-Amine Agonists with Selectivity for the Human β3-Adrenergic Receptor and Anti-Obesity and Anti-Diabetic Profiles
Authors: Lorca Marcos , Morales-Verdejo Cesar , Vásquez-Velásquez David , Andrades-Lagos Juan , Campanini-Salinas Javier , Soto-Delgado Jorge , Recabarren-Gajardo Gonzalo , Mella Jaime
Published: May 2018

The wide tissue distribution of the adrenergic β3 receptor makes it a potential target for the treatment of multiple pathologies such as diabetes, obesity, depression, overactive bladder (OAB), and cancer. Currently, there is only one drug on the market, mirabegron, approved for the treatment of OAB. In the present study, we have carried out an extensive structure-activity relationship analysis of a series of 41 aryloxypropanolamine compounds based on three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques. This is the first combined comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) study in a series of selective aryloxypropanolamines displaying anti-diabetes and anti-obesity pharmacological profiles. The best CoMFA and CoMSIA models presented values of r2ncv = 0.993 and 0.984 and values of r2test = 0.865 and 0.918, respectively. The results obtained were subjected to extensive external validation (q2, r2, r2m, etc.) and a final series of compounds was designed and their biological activity was predicted (best pEC50 = 8.561).
Molecular Diversity by Olefin Cross-Metathesis on Solid Support. Generation of Libraries of Biologically Promising β-Lactam Derivatives
Authors: Méndez Luciana , Poeylaut-Palena Andrés A. , Mata Ernesto G.
Published: May 2018

The application of the reagent-based diversification strategy for generation of libraries of biologically promising β-lactam derivatives is described. Key features are the versatility of the linker used and the cross-metathesis functionalization at the cleavage step. From an immobilized primary library, diversity was expanded by applying different cleavage conditions, leading to a series of cholesterol absorption inhibitor analogues together with interesting hybrid compounds through incorporation of a chalcone moiety.
Ethnobotany, Phytochemistry and Pharmacological Effects of Plants in Genus Cynanchum Linn. (Asclepiadaceae)
Authors: Han Lu , Zhou Xiuping , Yang Mengmeng , Zhou Li , Deng Xinxin , Wei Shijie , Wang Wenping , Wang Zhizhong , Qiao Xue , Bai Changcai
Published: May 2018

Genus Cynanchum L. belongs to the family Asclepiadaceae, which comprise more than 200 species distributed worldwide. In Chinese medical practice, numerous drugs (such as tablets and powders) containing different parts of plants of this genus are used to treat snake bites, bruises, osteoblasts, rheumatoid arthritis and tumors. A search for original articles published on the cynanchum genus was performed by using several resources, including Flora of China Official Website and various scientific databases, such as PubMed, SciFinder, the Web of Science, Science Direct, and China Knowledge Resource Integrated (CNKI). Advances in the botanical, ethnomedicinal, phytochemical, and pharmacological studies of this genus are reviewed in this paper. Results showed that more than 440 compounds, including C21 steroids, steroidal saponins, alkaloids, flavonoids and terpene, have been isolated and identified from Cynanchum plants up to now. In vivo and in vitro studies have shown that plants possess an array of biological activities, including anti-tumor, neuroprotective and anti-fungal effects. Popular traditional prescription of Cynanchum sp. was also summed up in this paper. However, many Cynanchum species have received little or no attention. Moreover, few reports on the clinical use and toxic effects of Cynanchum sp. are available. Further attention should be focused on the study of these species to gather information on their respective toxicology data and relevant quality-control measures and clinical value of the crude extracts, active compounds, and bioactive metabolites from this genus. Further research on Cynanchum sp. should be conducted, and bioactivity-guided isolation strategies should be emphasized. In addition, systematic studies of the chemical composition of plants should be enhanced.
The Late Embryogenesis Abundant Protein Family in Cassava (Manihot esculenta Crantz): Genome-Wide Characterization and Expression during Abiotic Stress
Authors: Wu Chunlai , Hu Wei , Yan Yan , Tie Weiwei , Ding Zehong , Guo Jianchun , He Guangyuan
Published: May 2018

Late embryogenesis abundant (LEA) proteins, as a highly diverse group of polypeptides, play an important role in plant adaptation to abiotic stress; however, LEAs from cassava have not been studied in cassava. In this study, 26 LEA members were genome-wide identified from cassava, which were clustered into seven subfamily according to evolutionary relationship, protein motif, and gene structure analyses. Chromosomal location and duplication event analyses suggested that 26 MeLEAs distributed in 10 chromosomes and 11 MeLEA paralogues were subjected to purifying selection. Transcriptomic analysis showed the expression profiles of MeLEAs in different tissues of stem, leaves, and storage roots of three accessions. Comparative transcriptomic analysis revealed that the function of MeLEAs in response to drought may be differentiated in different accessions. Compared with the wild subspecies W14, more MeLEA genes were activated in cultivated varieties Arg7 and SC124 after drought treatment. Several MeLEA genes showed induction under various stresses and related signaling treatments. Taken together, this study demonstrates the transcriptional control of MeLEAs in tissue development and the responses to abiotic stress in cassava and identifies candidate genes for improving crop resistance to abiotic stress.
Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.)
Authors: Baldermann Susanne , Homann Thomas , Neugart Susanne , Chmielewski Frank-M. , Götz Klaus-Peter , Gödeke Kristin , Huschek Gerd , Morlock Getrud E. , Rawel Harshadrai M.
Published: May 2018

Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information.
Soybean-Hop Alleviates Estrogen Deficiency-Related Bone Loss and Metabolic Dysfunction in Ovariectomized Rats Fed a High-Fat Diet
Authors: Noh Dasom , Lim Yeni , Lee Hansol , Kim Hyejin , Kwon Oran
Published: May 2018

Soybeans and hops have been traditionally used as a natural estrogen replacement therapy and their major active ingredients, isoflavones and prenylflavanones, are known to have estrogenic/antiestrogenic effects depending on the target organ. However, their potential benefits are still subject to controversies. The present study investigated the dual effect of soy isoflavones plus hop prenylflavanones (Soy-Hop) on bone loss and metabolic dysfunction under estrogen deficient condition. Rats were sham-operated (n = 10) or ovariectomized (OVX; n = 40) and then fed a high-fat diet (HFD) to develop hyperlipidemia in OVX rats within the experimental period of 8 weeks. The OVX/HFD rats were assigned to four groups to receive different doses of Soy-Hop (0, 30, 100, and 300 mg/kg) by oral gavage for 8 weeks. High-dose Soy-Hop significantly suppressed OVX/HFD-induced increases in food intake, body weight gain, fat mass, and circulating levels of leptin, adiponectin, LDL-cholesterol, total cholesterol, triglycerides, glucose, and insulin. High-dose Soy-Hop also attenuated OVX/HFD-induced elevation of osteocalcin, alkaline phosphatase, and CTX in plasma and RANKL/OPG gene expression ratio in femur. These findings were confirmed visually by confocal analysis of GLUT4 translocation in soleus muscle cells and micro-computed tomography scanning of the distal femoral epiphysis, respectively. These results suggest that Soy-Hop may have potential to ameliorate estrogen deficiency-related alterations in both metabolism and bone quality, at least in part, by hormonal factors secreted by adipocytes.
High Performance of Supercapacitor from PEDOT:PSS Electrode and Redox Iodide Ion Electrolyte
Authors: Gao Xing , Zu Lei , Cai Xiaomin , Li Ce , Lian Huiqin , Liu Yang , Wang Xiaodong , Cui Xiuguo
Published: May 2018

Insufficient energy density and poor cyclic stability is still challenge for conductive polymer-based supercapacitor. Herein, high performance electrochemical system has been assembled by combining poly (3,4-ethylenedioxythiophene) (PEDOT):poly (styrene sulfonate) (PSS) redox electrode and potassium iodide redox electrolyte, which provide the maximum specific capacity of 51.3 mAh/g and the retention of specific capacity of 87.6% after 3000 cycles due to the synergic effect through a simultaneous redox reaction both in electrode and electrolyte, as well as the catalytic activity for reduction of triiodide of the PEDOT:PSS.
Fabrication and Characterization of Nanoenergetic Hollow Spherical Hexanitrostibene (HNS) Derivatives
Authors: Cao Xiong , Deng Peng , Hu Shuangqi , Ren Lijun , Li Xiaoxia , Xiao Peng , Liu Yu
Published: May 2018

The spherization of nanoenergetic materials is the best way to improve the sensitivity and increase loading densities and detonation properties for weapons and ammunition, but the preparation of spherical nanoenergetic materials with high regularization, uniform size and monodispersity is still a challenge. In this paper, nanoenergetic hollow spherical hexanitrostibene (HNS) derivatives were fabricated via a one-pot copolymerization strategy, which is based on the reaction of HNS and piperazine in acetonitrile solution. Characterization results indicated the as-prepared reaction nanoenergetic products were HNS-derived oligomers, where a free radical copolymerization reaction process was inferred. The hollow sphere structure of the HNS derivatives was characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), and synchrotron radiation X-ray imaging technology. The properties of the nanoenergetic hollow spherical derivatives, including thermal decomposition and sensitivity are discussed in detail. Sensitivity studies showed that the nanoenergetic derivatives exhibited lower impact, friction and spark sensitivity than raw HNS. Thermogravimetric-differential scanning calorimeter (TG-DSC) results showed that continuous exothermic decomposition occurred in the whole temperature range, which indicated that nanoenergetic derivatives have a unique role in thermal applications. Therefore, nanoenergetic hollow spherical HNS derivatives could provide a new way to modify the properties of certain energetic compounds and fabricate spherical nanomaterials to improve the charge configuration.
Wetting Behaviors of a Nano-Droplet on a Rough Solid Substrate under Perpendicular Electric Field
Authors: Song Fenhong , Ma Long , Fan Jing , Chen Qicheng , Zhang Lihui , Li Ben Q.
Published: May 2018

Molecular dynamic simulations were adopted to study the wetting properties of nanoscale droplets on rough silicon solid substrate subject to perpendicular electric fields. The effect of roughness factor and electric field strength on the static and dynamic wetting behaviors of a nano-droplet on a solid surface was investigated at the molecular level. Results show that the static contact angle tends to decrease slightly and show small difference with the increase of roughness factor, while it shows an obvious increase for the ramp-shaped surface because the appearing bottom space reduces the wettability of solid surface. Additionally, under the electric field, a nano-droplet was elongated in the field direction and the equilibrium contact angle increases with the increase of electric field strength. The nano-droplet was completely stretched to be column-shaped at a threshold value of the field. Besides, accompanied by the shape variation of water droplets, the molecular dipole orientations of water molecules experience a remarkable change from a random disordered distribution to an ordered profile because of the realignment of water molecules induced by electric fields.