bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Biological and Chemical Synthesis of Schwertmannite at a Consistent Fe2+ Oxidation Efficiency and the Effect of Extracellular Polymeric Substances of Acidithiobacillus ferrooxidans on Biomineralization
Authors: Song Yongwei , Liu Yelin , Wang Heru
Published: September 2018

Schwertmannite is an environmental mineral material that can promote the natural passivation of heavy metal elements, thereby reducing environmental pollution from toxic elements. However, the fundamental reason for the difference between the chemically (H2O2-FeSO4) and biologically (Acidithiobacillus ferrooxidans-FeSO4) synthesized schwertmannite is still unclear. In this study, X-ray diffraction, scanning electron microscopy, the Brunauer–Emmett–Teller method, and X-ray fluorescence spectrometry were used to compare the structure, specific surface area, and elemental composition of schwertmannite synthesized by biological and chemical methods. The removal capacity of As(III) by the two kinds of schwertmannite and the effects of extracellular polymeric substances (EPS) on biogenetic schwertmannite were also investigated. At a consistent Fe2+ oxidation efficiency, the chemical method synthesized more schwertmannite than the biological method over a 60-h period. The biosynthesized schwertmannite had a “chestnut shell” shape, with a larger particle size and specific surface than the chemically synthesized schwertmannite, which was relatively smooth. The saturated adsorption capacities of the biologically and chemically synthesized schwertmannite were 117.0 and 87.0 mg·g−1, respectively. After exfoliation of the EPS from A. ferrooxidans, the biosynthesized schwertmannite displayed a “wool ball” shape, with rough particle surfaces, many microporous structures, and a larger specific surface area. The schwertmannite yield also increased by about 45% compared with that before exfoliation, suggesting that the secretion of EPS by A. ferrooxidans can inhibit the formation of schwertmannite.
Investigation on the Thermal Behavior, Mechanical Properties and Reaction Characteristics of Al-PTFE Composites Enhanced by Ni Particle
Authors: Wu Jiaxiang , Wang Huaixi , Fang Xiang , Li Yuchun , Mao Yiming , Yang Li , Yin Qin , Wu Shuangzhang , Yao Miao , Song Jiaxing
Published: September 2018

Al-PTFE (aluminum-polytetrafluoroethene) is regarded as one of the most promising reactive materials (RMs). In this work, Ni (Nickel) was added to Al-PTFE composites for the purpose of improving the energy density and damage effect. To investigate the thermal behavior, mechanical properties and reaction characteristics of the Al-Ni-PTFE composites, an Al-PTFE mixture and an Al-Ni mixture were prepared by ultrasonic mixing. Six types of Al-Ni-PTFE specimens with different component mass ratios were prepared by molding sintering. Simultaneous thermal analysis experiments were carried out to characterize the thermal behavior of the Al-PTFE mixture and the Al-Ni mixture. Quasi-static compression tests were performed to analyze the mechanical properties and reaction characteristics of the Al-Ni-PTFE specimens. The results indicate that the reaction onset temperature of Al-Ni (582.7 °C) was similar to that of Al-PTFE (587.6 °C) and that the reaction heat of Al-Ni (991.9 J/g) was 12.5 times higher than that of Al-PTFE (79.6 J/g). With the increase of Ni content, the material changed from ductile to brittle and the strain hardening modulus and compressive strength rose first and then subsequently decreased, reaching a maximum of 51.35 MPa and 111.41 MPa respectively when the volume fraction of Ni was 10%. An exothermic reaction occurred for the specimens with a Ni volume fraction no more than 10% under quasi-static compression, accompanied by the formation of Ni-Al intermetallic compounds. In the Al-Ni-PTFE system, the reaction between Al and PTFE preceded the reaction between Al and Ni and the feasibility of increasing the energy density and damage effect of the Al-Ni-PTFE reactive material by means of Ni-Al reaction was proved.
Electrospinning of Ultrafine Conducting Polymer Composite Nanofibers with Diameter Less than 70 nm as High Sensitive Gas Sensor
Authors: Zhang Qianqian , Wang Xiaoxiong , Fu Jie , Liu Ruiqiang , He Hongwei , Ma Jianwei , Yu Miao , Ramakrishna Seeram , Long Yunze
Published: September 2018

Polyvinyl alcohol/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PVA/PEDOT:PSS) composite ultrafine fibers were successfully fabricated by high pressure airflow assisted electrospinning. The electrical properties of PVA/PEDOT:PSS nanofibers with different diameters were characterized. The average diameter of the nanofibers can be down to 68 nm. Due to its large specific surface area, ammonia sensing of the ultrafine nanofibers is more sensitive than the traditional electrospun fibers (average fiber diameter of 263 nm). The ammonia sensing properties of the samples were tested by impedance analysis. The results show that ultrafine PVA/PEDOT:PSS nanofibers are more suitable for detecting low concentrations of ammonia with higher sensitivity.
Preparation and Characterization of Magnesium Alloy Containing Al2Y Particles
Authors: Jiang Zhongtao , Feng Jun , Chen Qiaowang , Jiang Shan , Dai Jiahong , Jiang Bin , Pan Fusheng
Published: September 2018

A magnesium alloy containing Al2Y particles was successfully fabricated by changing the content of Al in the Mg-6Y alloy melt. Its microstructure and mechanical properties were subsequently characterized. The results show that two types of Al2Y particles were discovered in the Mg-6Y-xAl (x = 0.5–5) alloys, which are namely the polygonal particles in the pre-precipitated phase and the discontinuous network of particles in the eutectic phase. With an increase in Al content, the amount of pre-precipitated Al2Y increases and the eutectic decreases gradually. When the Al content is 5 wt %, Al2Y particles are almost all in the pre-precipitated phase in the Mg-6Y alloy. After hot extrusion, the YA65 alloy could be regarded as the Mg master alloy that contains Al2Y particles with heterogeneous nucleation capability or Al2Y particle-reinforced magnesium matrix composites. The tensile strength of the as-extruded magnesium alloy is significantly improved at ambient temperatures.
Three-Dimensional Bioprinting of Cartilage by the Use of Stem Cells: A Strategy to Improve Regeneration
Authors: Roseti Livia , Cavallo Carola , Desando Giovanna , Parisi Valentina , Petretta Mauro , Bartolotti Isabella , Grigolo Brunella
Published: September 2018

Cartilage lesions fail to heal spontaneously, leading to the development of chronic conditions which worsen the life quality of patients. Three-dimensional scaffold-based bioprinting holds the potential of tissue regeneration through the creation of organized, living constructs via a “layer-by-layer” deposition of small units of biomaterials and cells. This technique displays important advantages to mimic natural cartilage over traditional methods by allowing a fine control of cell distribution, and the modulation of mechanical and chemical properties. This opens up a number of new perspectives including personalized medicine through the development of complex structures (the osteochondral compartment), different types of cartilage (hyaline, fibrous), and constructs according to a specific patient’s needs. However, the choice of the ideal combination of biomaterials and cells for cartilage bioprinting is still a challenge. Stem cells may improve material mimicry ability thanks to their unique properties: the immune-privileged status and the paracrine activity. Here, we review the recent advances in cartilage three-dimensional, scaffold-based bioprinting using stem cells and identify future developments for clinical translation. Database search terms used to write this review were: “articular cartilage”, “menisci”, “3D bioprinting”, “bioinks”, “stem cells”, and “cartilage tissue engineering”.
Macro-Encapsulation of Inorganic Phase-Change Materials (PCM) in Metal Capsules
Authors: Höhlein Stephan , König-Haagen Andreas , Brüggemann Dieter
Published: September 2018

The design of phase-change material (PCM)-based thermal energy storage (TES) systems is challenging since a lot of PCMs have low thermal conductivities and a considerable volume change during phase-change. The low thermal conductivity restricts energy transport due to the increasing thermal resistance of the progressing phase boundary and hence large heat transfer areas or temperature differences are required to achieve sufficient storage power. An additional volume has to be considered in the storage system to compensate for volume change. Macro-encapsulation of the PCM is one method to overcome these drawbacks. When designed as stiff containers with an air cushion, the macro-capsules compensate for volume change of the PCM which facilitates the design of PCM storage systems. The capsule walls provide a large surface for heat transfer and the thermal resistance is reduced due to the limited thickness of the capsules. Although the principles and advantages of macro-encapsulation have been well known for many years, no detailed analysis of the whole encapsulation process has been published yet. Therefore, this research proposes a detailed development strategy for the whole encapsulation process. Various possibilities for corrosion protection, fill and seal strategies and capsule geometries are studied. The proposed workflow is applied for the encapsulation of the salt hydrate magnesiumchloride hexahydrate (MCHH, MgCl 2 · 6 H 2 O) within metal capsules but can also be assigned to other material combinations.
A Bibliometric and Topic Analysis on Future Competences at Smart Factories
Authors: Jerman Andrej , Pejić Bach Mirjana , Bertoncelj Andrej
Published: September 2018

The aim of the study is to review the topic of competences that will be present at smart factories. The study used bibliometric and topic analysis to achieve insight into new trends in Industry 4.0. Bibliometric analysis and topic mining was done on 43 peer-reviewed journal articles and conference papers, published before July 2018 in the Thomson Reuters’ Web of Science and Scopus databases, using the software tool Statistica Data Miner. Results are segmented into four sections: (1) personnel development in learning organizations, (2) training techniques for personnel, (3) future engineering profiles and engineering education, and (4) relational capabilities. Each section is thoroughly discussed in this paper. The study contributes to the pool of knowledge on Industry 4.0 phenomena by compiling competences needed at smart factories in the future.
How to Make a Better Magnet? Insertion of Additional Bridging Ligands into a Magnetic Coordination Polymer
Authors: Handzlik Gabriela , Pinkowicz Dawid
Published: September 2018

A three-dimensional cyanide-bridged coordination polymer based on FeII (S = 2) and NbIV (S = 1/2) {[FeII(H2O)2]2[NbIV(CN)8]·4H2O}n (Fe2Nb) was modified at the self-assembly stage by inserting an additional formate HCOO− bridge into its cyanide framework. The resulting mixed-bridged {(NH4)[(H2O)FeII-(μ-HCOO)-FeII(H2O)][NbIV(CN)8]·3H2O}n (Fe2NbHCOO) exhibited additional FeII-HCOO-FeII structural motifs connecting each of the two FeII centers. The insertion of HCOO− was possible due to the substitution of some of the aqua ligands and crystallization water molecules in the parent framework by formate anions and ammonium cations. The formate molecular bridge not only shortened the distance between FeII ions in Fe2NbHCOO from 6.609 Å to 6.141 Å, but also created additional magnetic interaction pathways between the magnetic centers, resulting in an increase in the long range magnetic ordering temperature from 43 K for Fe2Nb to 58 K. The mixed-bridged Fe2NbHCOO also showed a much broader magnetic hysteresis loop of 0.102 T, compared to 0.013 T for Fe2Nb.
Total Synthesis of the Highly N-Methylated Peptides Carmabin A and Dragomabin
Authors: Ye Baijun , Jiang Peng , Zhang Tingrong , Sun Yuanjun , Hao Xin , Cui Yingjun , Wang Liang , Chen Yue
Published: September 2018

The first total synthesis of carmabin A and dragomabin was achieved at 52.3 mg and 43.8 mg scale, respectively. The synthesis led to determination of the configuration of carmabin A and reassignment of the configuration of dragomabin at the stereogenic centre on the alkyne-bearing fragment.
Natural Product Chemistry of Gorgonian Corals of Genus Junceella–Part III
Authors: Chung Hsu-Ming , Wang Yi-Chen , Tseng Chung-Chih , Chen Nan-Fu , Wen Zhi-Hong , Fang Lee-Shing , Hwang Tsong-Long , Wu Yang-Chang , Sung Ping-Jyun
Published: September 2018

The structures, names, bioactivities, and references of 82 natural products, including 48 new metabolites, purified from the gorgonian corals belonging to the genus Junceella are described in this review. All compounds mentioned in this review were obtained from Junceella fragilis, Junceella gemmacea, Junceella juncea, and Junceella sp., collected from tropical Indo-Pacific Ocean. Some of these compounds exhibited potential biomedical activities.
Enhanced Fracture Strength in the Working Layer of Rolls Manufactured in Ni-Hard Cast Iron Alloyed with Mo, Nb and Mg
Authors: Cofiño-Villar Alberto , Alvarez-Antolin Jose Florentino , Asensio-Lozano Juan
Published: September 2018

One of the main in-service failure mechanisms of the work-rolls used in hot strip mill finishing stands is surface spalling. The indefinite chill double-poured rolls usually comprise of a peripheral working layer made of crushed Ni-hard cast iron and a grey cast iron core, mostly pearlitic matrix with spheroidal graphite. To enhance its wear resistance, the working layer can be alloyed with Mo and Nb. The possible cracking and spalling of the surfaces of these work-rolls is strongly influenced by the presence of carbides and the continuity of their network. The flexural and impact toughness tests are reliable testing methods to assess these properties. The aim of this paper is to identify those manufacturing factors that have a significant effect on the flexural strength and toughness of this material, correlating the results with the volume fraction of precipitated carbides. It is worth highlighting, among the analysed factors are the liquidus temperature, the %Si, the use of an inoculant with traces of Lanthanum, and inoculation with different amounts of FeB, SiCa and Mg. Inoculation with SiCa is found to have a positive effect on the toughness of the material, breaking up the continuity of the carbide network, while FeB is found to act as a heterogeneous nucleant for NbC precipitation. However, high FeB contents reduce flexural strength and do not have a significant effect on the hardness of the material. To enhance the fracture toughness of the working layer, a liquidus temperature in the 1270–1275 °C range is recommended, as well as inoculating the ladle with Mg, 3 kg/T FeB and 0.6 kg/T SiCa.
Physical Modelling of Aluminum Refining Process Conducted in Batch Reactor with Rotary Impeller
Authors: Saternus Mariola , Merder Tomasz
Published: September 2018

The refining process is one of the essential stages of aluminum production. Its main aim is to remove hydrogen, that causes porosity and weakens the mechanical and physical properties of casting aluminum. The process is mainly conducted by purging inert gas through the liquid metal, using rotary impellers. The geometry of the impellers and the processing parameters, such as flow rate of gas and rotary impeller speed, influence the gas dispersion level, and therefore the efficiency of the process. Improving the process, and optimization of parameters, can be done by physical modelling. In this paper, the research was carried out with the use of a water model of batch reactor, testing three different rotary impellers. Varied methods were used: visualization, which can help to evaluate the level of dispersion of gas bubbles in liquid metal; determination of residence time distribution (RTD) curves, which was obtained by measuring the conductivity of NaCl tracer in the fluid; and indirect studies, completed by measuring the content of dissolved oxygen in water to simulate hydrogen desorption. The research was carried out for different processing parameters, such as flow rate of refining gas (5–25 L·min−1) and rotary impeller speed (3.33–8.33 s−1). The obtained results were presented graphically and discussed in detail.
Synthesis of Bulk Amorphous Alloy from Fe-Base Powders by Explosive Consolidation
Authors: Li Jianbin , Lu Ming , Ai Yongbao , Tao Cong , Xiong Yun
Published: September 2018

A Fe61Cr2Nb3Si12B22 amorphous alloy rod sample of 8.8 mm diameter has been successfully prepared through explosive consolidation. The structure and thermal stability of the as-synthesized sample have been analyzed through X-ray diffraction (XRD) and differential scanning calorimeter (DSC) analysis. The results demonstrate that the sample still retains an amorphous structure, and the glass transition temperature (Tg), the crystallization onset temperature (Tx), the supercooled liquid zone (ΔTx) (Tx − Tg) and the reduced glass transition temperatures (Trg) (Tg/Tm) are 784 K, 812 K, 28 K, and 0.556, respectively. Its microstructure has been investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The average microhardness of the alumina compact is about 1069 HV.
Effect of Powder Feedstock on Microstructure and Mechanical Properties of the 316L Stainless Steel Fabricated by Selective Laser Melting
Authors: Chen Wei , Yin Guangfu , Feng Zai , Liao Xiaoming
Published: September 2018

Additive manufacturing by selective laser melting (SLM) was used to investigate the effect of powder feedstock on 316L stainless steel properties include microstructure, relative density, microhardness and mechanical properties. Gas atomized SS316L powders of three different particle size distribution were used in this study. Microstructural investigations were done by scanning electron microscopy (SEM). Tensile tests were performed at room temperatures. Microstructure characterization revealed the presence of hierarchical structures consisting of solidified melt pools, columnar grains and multiform shaped sub-grains. The results showed that the SLM sample from the fine powder obtained the highest mechanical properties with ultimate tensile strength (UTS) of 611.9 ± 9.4 MPa and yield strength (YS) of 519.1 ± 5.9 MPa, and an attendant elongation (EL) of 14.6 ± 1.9%, and a maximum of 97.92 ± 0.13% and a high microhardness 291 ± 6 HV0.1. It has been verified that the fine powder (~16 μm) could be used in additive manufacturing with proper printing parameters.
Mind the Gap: Mapping Mass Spectral Databases in Genome-Scale Metabolic Networks Reveals Poorly Covered Areas
Authors: Frainay Clément , Schymanski Emma L. , Neumann Steffen , Merlet Benjamin , Salek Reza M. , Jourdan Fabien , Yanes Oscar
Published: September 2018

The use of mass spectrometry-based metabolomics to study human, plant and microbial biochemistry and their interactions with the environment largely depends on the ability to annotate metabolite structures by matching mass spectral features of the measured metabolites to curated spectra of reference standards. While reference databases for metabolomics now provide information for hundreds of thousands of compounds, barely 5% of these known small molecules have experimental data from pure standards. Remarkably, it is still unknown how well existing mass spectral libraries cover the biochemical landscape of prokaryotic and eukaryotic organisms. To address this issue, we have investigated the coverage of 38 genome-scale metabolic networks by public and commercial mass spectral databases, and found that on average only 40% of nodes in metabolic networks could be mapped by mass spectral information from standards. Next, we deciphered computationally which parts of the human metabolic network are poorly covered by mass spectral libraries, revealing gaps in the eicosanoids, vitamins and bile acid metabolism. Finally, our network topology analysis based on the betweenness centrality of metabolites revealed the top 20 most important metabolites that, if added to MS databases, may facilitate human metabolome characterization in the future.
A 3D-Printed Millifluidic Platform Enabling Bacterial Preconcentration and DNA Purification for Molecular Detection of Pathogens in Blood
Authors: Kim Yonghee , Lee Jinyeop , Park Sungsu
Published: September 2018

Molecular detection of pathogens in clinical samples often requires pretreatment techniques, including immunomagnetic separation and magnetic silica-bead-based DNA purification to obtain the purified DNA of pathogens. These two techniques usually rely on handling small tubes containing a few millilitres of the sample and manual operation, implying that an automated system encompassing both techniques is needed for larger quantities of the samples. Here, we report a three-dimensional (3D)-printed millifluidic platform that enables bacterial preconcentration and genomic DNA (gDNA) purification for improving the molecular detection of target pathogens in blood samples. The device consists of two millichannels and one chamber, which can be used to preconcentrate pathogens bound to antibody-conjugated magnetic nanoparticles (Ab-MNPs) and subsequently extract gDNA using magnetic silica beads (MSBs) in a sequential manner. The platform was able to preconcentrate very low concentrations (1–1000 colony forming units (CFU)) of Escherichia coli O157:H7 and extract their genomic DNA in 10 mL of buffer and 10% blood within 30 min. The performance of the platform was verified by detecting as low as 1 CFU of E. coli O157:H7 in 10% blood using either polymerase chain reaction (PCR) with post gel electrophoresis or quantitative PCR. The results suggest that the 3D-printed millifluidic platform is highly useful for lowering the limitations on molecular detection in blood by preconcentrating the target pathogen and isolating its DNA in a large volume of the sample.
Gastroprotective Activity of Parastrephia quadrangularis (Meyen), Cabrera from the Atacama Desert
Authors: Ardiles Alejandro , Barrientos Ruth , Simirgiotis Mario J. , Bórquez Jorge , Sepúlveda Beatriz , Areche Carlos
Published: September 2018

Forty-three metabolites including several methoxylated flavonoids, tremetones, and ent-clerodane diterpenes were accurately identified for the first time in the ethanolic extract of P. quadrangularis by means of hyphenated UHPLC-quadrupole Orbitrap mass spectrometry, and seven isolated compounds were tested regarding gastroprotective activity using the HCl/EtOH-induced lesion model in mice. A new tremetone (compound 6) is reported based on spectroscopic evidence. The isolated clerodanes and tremetones showed gastroprotective activity in a mouse model, evidenced by compound 7 (p-coumaroyloxytremetone), which showed the highest gastroprotective activity (76%), which was higher than the control drug lansoprazole (72%). Our findings revealed that several constituents of this plant have gastroprotective activity, and particularly, p-coumaroyloxytremetone could be considered as a lead molecule to explore new gastroprotective agents. This plant is a rich source of biologically active tremetones and terpenoids which can support the ethnobotanical use of the plant.
Prenylated Diphenyl Ethers from the Marine Algal-Derived Endophytic Fungus Aspergillus tennesseensis
Authors: Li Zhao-Xia , Wang Xiu-Fang , Ren Guang-Wei , Yuan Xiao-Long , Deng Ning , Ji Gui-Xia , Li Wei , Zhang Peng
Published: September 2018

Considerable attention has been paid to marine derived endophytic fungi, owing to their capacity to produce novel secondary metabolites with potent bioactivities. In this study, two new compounds with a prenylated diphenyl ether structure—diorcinol L (1) and (R)-diorcinol B (2)—were isolated from the marine algal-derived endophytic fungus Aspergillus tennesseensis, along with seven known compounds: (S)-diorcinol B (3), 9-acetyldiorcinol B (4), diorcinol C (5), diorcinol D (6), diorcinol E (7), diorcinol J (8), and a dihydrobenzofuran derivative 9. Their structures were elucidated by extensive NMR spectroscopy studies. Compound 2 represents the first example of an R-configuration in the prenylated moiety. All these isolated compounds were examined for antimicrobial and cytotoxic activities. Compounds 1–9 exhibited antimicrobial activities against some human- and plant-pathogenic microbes with MIC values ranging from 2 to 64 μg/mL. Moreover, compound 9 displayed considerable inhibitory activity against the THP-1 cell line in vitro, with an IC50 value of 7.0 μg/mL.
Prunetin Relaxed Isolated Rat Aortic Rings by Blocking Calcium Channels
Authors: Kim Bumjung , Jo Cheolmin , Choi Ho-Young , Lee Kyungjin
Published: September 2018

Prunetin, a component of herbal medicines and various foods, such as pea, peach, cherry, and Prunus yedoensis, is a useful pharmacological compound. We previously reported the potent vasorelaxant effect of the bark of P. yedoensis. Therefore, we investigated the vasorelaxant activities of prunetin on isolated rat aortic rings and hypotensive activity on spontaneously hypertensive rats (SHR) in this study. In the present study, prunetin (1–30 μg/mL) relaxed isolated rat aortic rings pre-contracted by phenylephrine (PE) in a concentration-dependent manner. Pre-incubation with prunetin (3 and 10 μg/mL) inhibited vasoconstriction induced by the supply of Ca2+ in rat aortic rings pre-contracted with PE or KCl in a Ca2+-free Krebs–Henseleit (KH) buffer. Prunetin (10 μg/mL) pre-treatment also inhibited caffeine-induced contraction of aortic rings in a Ca2+-free KH buffer. To investigate the hypotensive effect of prunetin, the systolic blood pressure (SBP) of the SHR was measured by using a tail cuff assay. The SBP of SHR was significantly lower in the prunetin (25 mg/kg)-treated group. These results suggested that prunetin decreased blood pressure and relaxed blood vessels by blocking receptor-operated calcium channels, voltage-dependent calcium channels, and ryanodine receptor channels.
Compound Ammonium Glycyrrhizin Protects Hepatocytes from Injury Induced by Lipopolysaccharide/Florfenicol through a Mitochondrial Pathway
Authors: Li Wenyang , Li Ying , Jiang Xiangyuan , Li Xiaohui , Yu Zugong
Published: September 2018

Florfenicol (FFC), a widely used drug for chicken diseases, can aggravate lipopolysaccharide (LPS) damage to the liver. For this condition, natural or synthetic products displaying strong antioxidant capacity are expected to prevent LPS/FFC from inducing liver injury, so in our study, the compound ammonium glycyrrhizin (CAG) is used as the protective drug to decrease the injury to liver. The research aims to illustrate the underlying mechanism of combining LPS with FFC-induced liver injury and the protective role of CAG by using primary chicken hepatocytes as an in vitro model. The results show that LPS/FFC induced cell apoptosis and CAG protected hepatocytes from injury. The permeability of the cell membrane is elevated by LPS/FFC, leading to the efflux of enzymes (ALT, AST). Flow cytometry analysis indicates that LPS/FFC treatment increased the apoptosis rate significantly. Furthermore, with the up-regulation of apoptosis genes bax, cytochrome c and the down-regulation of bcl-2, caspase-3 and caspase-9 are activated at the gene level. LPS/FFC-induced mitochondrial damage is accompanied by a significant decrease in mitochondrial membrane potential (MMP) and severe mitochondrial damage. However, CAG improves the situation for the purpose of protecting the liver. In conclusion, it is speculated that LPS/FFC induces severe liver injury through apoptosis and the CAG protects hepatocytes from injury via the mitochondria-mediated apoptosis pathway.
Perceptions on Authenticity in Chat Bots
Authors: Neururer Mario , Schlögl Stephan , Brinkschulte Luisa , Groth Aleksander
Published: September 2018

In 1950, Alan Turing proposed his concept of universal machines, emphasizing their abilities to learn, think, and behave in a human-like manner. Today, the existence of intelligent agents imitating human characteristics is more relevant than ever. They have expanded to numerous aspects of daily life. Yet, while they are often seen as work simplifiers, their interactions usually lack social competence. In particular, they miss what one may call authenticity. In the study presented in this paper, we explore how characteristics of social intelligence may enhance future agent implementations. Interviews and an open question survey with experts from different fields have led to a shared understanding of what it would take to make intelligent virtual agents, in particular messaging agents (i.e., chat bots), more authentic. Results suggest that showcasing a transparent purpose, learning from experience, anthropomorphizing, human-like conversational behavior, and coherence, are guiding characteristics for agent authenticity and should consequently allow for and support a better coexistence of artificial intelligence technology with its respective users.
Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy
Authors: Jia Min , Li Shenmiao , Zang Liguo , Lu Xiaonan , Zhang Hongyan
Published: September 2018

Analyzing biomolecules is essential for disease diagnostics, food safety inspection, environmental monitoring and pharmaceutical development. Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for detecting biomolecules due to its high sensitivity, rapidness and specificity in identifying molecular structures. This review focuses on the SERS analysis of biomolecules originated from humans, animals, plants and microorganisms, combined with nanomaterials as SERS substrates and nanotags. Recent advances in SERS detection of target molecules were summarized with different detection strategies including label-free and label-mediated types. This comprehensive and critical summary of SERS analysis of biomolecules might help researchers from different scientific backgrounds spark new ideas and proposals.
Effect of Contact Pressure on the Performance of Carbon Nanotube Arrays Thermal Interface Material
Authors: Pei Yu , Zhong Hongmei , Wang Mengyu , Zhang Peng , Zhao Yang
Published: September 2018

Vertically aligned carbon nanotube (CNT) arrays are promising candidates for advanced thermal interface materials (TIMs) since they possess high mechanical compliance and high intrinsic thermal conductivity. Some of the previous works indicate that the CNT arrays in direct dry contact with the target surface possess low contact thermal conductance, which is the dominant thermal resistance. Using a phase sensitive transient thermo-reflectance (PSTTR) technique, we measure the thermal conductance between CNT arrays and copper (Cu) surfaces under different pressures. The experiments demonstrated that the contact force is one of the crucial factors for optimizing the thermal performance of CNT array-based TIMs. The experimental results suggest that the Cu-CNT arrays’ contact thermal conductance has a strong dependence on the surface deformation and has an order of magnitude rise as the contact pressure increases from 0.05 to 0.15 MPa. However, further increase of the contact pressure beyond 0.15 MPa has little effect on the contact thermal resistance. This work could provide guidelines to determine the minimum requirement of packaging pressure on CNT TIMs.
Modification of Microelectrode Arrays with High Surface Area Dendritic Platinum 3D Structures: Enhanced Sensitivity for Oxygen Detection in Ionic Liquids
Authors: Hussain Ghulam , O’Mullane Anthony P. , Silvester Debbie S.
Published: September 2018

Electrochemical gas sensors are often used for identifying and quantifying redox-active analyte gases in the atmosphere. However, for amperometric sensors, the current signal is usually dependent on the electroactive surface area, which can become small when using microelectrodes and miniaturized devices. Microarray thin-film electrodes (MATFEs) are commercially available, low-cost devices that give enhanced current densities compared to mm-sized electrodes, but still give low current responses (e.g., less than one nanoamp), when detecting low concentrations of gases. To overcome this, we have modified the surface of the MATFEs by depositing platinum into the recessed holes to create arrays of 3D structures with high surface areas. Dendritic structures have been formed using an additive, lead acetate (Pb(OAc)2) into the plating solution. One-step and two-step depositions were explored, with a total deposition time of 300 s or 420 s. The modified MATFEs were then studied for their behavior towards oxygen reduction in the room temperature ionic liquid (RTIL) [N8,2,2,2][NTf2]. Significantly enhanced currents for oxygen were observed, ranging from 9 to 16 times the current of the unmodified MATFE. The highest sensitivity was obtained using a two-step deposition with a total time of 420 s, and both steps containing Pb(OAc)2. This work shows that commercially-available microelectrodes can be favorably modified to give significantly enhanced analytical performances.
Effects of Marine n-3 Polyunsaturated Fatty Acids on Heart Rate Variability and Heart Rate in Patients on Chronic Dialysis: A Randomized Controlled Trial
Authors: Rantanen Jesper M. , Riahi Sam , Johansen Martin B. , Schmidt Erik B. , Christensen Jeppe H.
Published: September 2018

Marine n-3 polyunsaturated fatty acids (PUFA) may improve autonomic dysfunction, as indicated by an increase in heart rate variability (HRV) and reduce the risk of sudden cardiac death. Hence, the aim of this study was to investigate the effects of marine n-3 PUFA on 24-h HRV in patients on chronic dialysis, who have a high risk of sudden cardiac death. Between June 2014 and March 2016, 112 patients on chronic dialysis from Denmark were allocated to a daily supplement of 2 g marine n-3 PUFA or control for three months in a randomized, double-blinded, controlled trial. A 48-h Holter monitoring was performed and mean 24-h HRV indices for the two days were available in 85 patients. The mean age was 62.3 years (SD: 14.3) and median dialysis vintage was 1.7 years (IQR: 0.5, 6.4). Within-group and between-group changes in outcome were evaluated by a paired and two sample t-test, respectively. Marine n-3 PUFA did not change the primary endpoint SDNN (SD of all RR-intervals) reflecting overall HRV, but other HRV indices increased and the mean RR-interval increased significantly, corresponding to a decrease in heart rate by 2.5 beats per minute (p = 0.04). In conclusion, marine n-3 PUFA did not change SDNN, but the mean heart rate was significantly reduced and changes in other HRV-indices were also observed, indicating an increase in vagal modulation that might be protective against malignant ventricular arrhythmias.
Inappropriate Medication Use in Hospitalized Patients Diagnosed with Parkinson’s Disease
Authors: Cox Nicholas , Louie Jessica , Sederholm Benson
Published: September 2018

The purpose of this study was to evaluate the rate at which potentially inappropriate medications were administered for patients diagnosed with Parkinson’s disease (PD). This is a single-center, retrospective, case cohort study with data collected at an academic medical center between January 2010 and December 2013. Participants included all adult patients with admission diagnosis codes for PD. Included patients were screened for administrations of 27 potentially inappropriate medications and two potentially appropriate medications to be used for comparison. There were 1736 patients who met inclusion criteria with 175 documented administrations of potentially inappropriate medications to 77 patients. Patients who received potentially inappropriate medications had a longer mean duration of stay than the baseline population of PD patients (3.3 days vs. 1.9 days, p-value < 0.001). Despite recommendations to avoid certain medications in PD patients, a substantial number of administrations still occurred. The use of these medications can have clinical implications and our findings demonstrate increases in duration of stay. The findings from this study can assist in developing technological alerts to reduce inappropriate prescribing to PD patients. Larger prospective studies are warranted to further investigate the administration of inappropriate medications to patients diagnosed with PD.
Highly-Efficient Longitudinal Second-Harmonic Generation from Doubly-Resonant AlGaAs Nanoantennas
Authors: Xu Lei , Rahmani Mohsen , Smirnova Daria , Zangeneh Kamali Khosro , Zhang Guoquan , Neshev Dragomir , Miroshnichenko Andrey E.
Published: September 2018

We design an asymmetric nonlinear optical nanoantenna composed of a dielectric nanodisc and an adjacent nanobar. The proposed composite structure made of AlGaAs exhibits resonant response at both the fundamental and doubled frequencies. Being driven by the strong magnetic dipole resonance at the pump wavelength and a high-quality mode at the harmonic wavelength, the efficient second-harmonic radiation is generated predominantly along the vertical directions under the normally incident plane-wave excitation.
Numerical Investigation of the Failure Mechanism of Transversely Isotropic Rocks with a Particle Flow Modeling Method
Authors: Yang Xu-Xu , Jing Hong-Wen , Qiao Wei-Guo
Published: September 2018

Transversely isotropic rocks are commonly encountered in rock engineering practices, and their strength and failure behavior is often governed by the property of anisotropy. The particle flow modeling method was utilized to investigate the failure mechanism of transversely isotropic rocks subject to uniaxial compressive loading. The details for establishing transversely isotropic rock models were first presented, and then a parametric study was carried out to look into the effect of interface properties on the failure mode and strength of transversely isotropic rock models by varying the interface dip angle. The smooth joint model was incorporated to create interfaces for the completeness of establishing transversely isotropic rock models with the particle flow modeling method. Accordingly, three failure modes observed in transversely isotropic rock models with varying dip angles were tensile failure across interfaces, shear failure along interfaces, and tensile failure along interfaces. Furthermore, the interface mechanical parameters were found to differently influence the failure behavior of transversely isotropic rock models. The bonded joint cohesion and bonded joint friction angle that contribute to the shear strength of interfaces have considerable influence on the uniaxial compressive strength (UCS) values, while the joint coefficient of friction and joint tensile strength have a slight influence on the UCS values. The findings in this paper indicated the importance of interfaces in estimating failure behavior of transversely isotropic rocks.
Combining UAV-Based Vegetation Indices and Image Classification to Estimate Flower Number in Oilseed Rape
Authors: Wan Liang , Li Yijian , Cen Haiyan , Zhu Jiangpeng , Yin Wenxin , Wu Weikang , Zhu Hongyan , Sun Dawei , Zhou Weijun , He Yong
Published: September 2018

Remote estimation of flower number in oilseed rape under different nitrogen (N) treatments is imperative in precision agriculture and field remote sensing, which can help to predict the yield of oilseed rape. In this study, an unmanned aerial vehicle (UAV) equipped with Red Green Blue (RGB) and multispectral cameras was used to acquire a series of field images at the flowering stage, and the flower number was manually counted as a reference. Images of the rape field were first classified using K-means method based on Commission Internationale de l’Éclairage (CIE) L*a*b* space, and the result showed that classified flower coverage area (FCA) possessed a high correlation with the flower number (r2 = 0.89). The relationships between ten commonly used vegetation indices (VIs) extracted from UAV-based RGB and multispectral images and the flower number were investigated, and the VIs of Normalized Green Red Difference Index (NGRDI), Red Green Ratio Index (RGRI) and Modified Green Red Vegetation Index (MGRVI) exhibited the highest correlation to the flower number with the absolute correlation coefficient (r) of 0.91. Random forest (RF) model was developed to predict the flower number, and a good performance was achieved with all UAV variables (r2 = 0.93 and RMSEP = 16.18), while the optimal subset regression (OSR) model was further proposed to simplify the RF model, and a better result with r2 = 0.95 and RMSEP = 14.13 was obtained with the variable combination of RGRI, normalized difference spectral index (NDSI (944, 758)) and FCA. Our findings suggest that combining VIs and image classification from UAV-based RGB and multispectral images possesses the potential of estimating flower number in oilseed rape.
Liquid Level Sensor Based on a V-Groove Structure Plastic Optical Fiber
Authors: Teng Chuanxin , Liu Houquan , Deng Hongchang , Deng Shijie , Yang Hongyan , Xu Ronghui , Chen Ming , Yuan Libo , Zheng Jie
Published: September 2018

A high sensitivity and easily fabricated liquid level sensor based on the V-groove structure plastic optical fiber (POF) was described. In the design, the V-groove structure on the POF is produced by using a die-press-print method, which effectively reduces the complexity of the fabrication process and makes it easier for mass production of liquid level sensors. This greatly enhances the usefulness of the proposed sensor in cost effective liquid level sensing applications. The transmission characteristic of the POF could be changed when the V-groove structure was immerged or emerged by the rising or falling liquid. The liquid level sensing performances for the sensor probes with different structural parameters were investigated, and the sensor performances for the liquids with different refractive indices and the sensor dynamic response were also tested. Experimental results show that the sensor’s sensitivity can reach 0.0698 mm−1, with a resolution of 2.5 mm. Results also show that the sensor has a fast response time of 920 ms.
Application of Time-Domain Full Waveform Inversion to Cross-Hole Radar Data Measured at Xiuyan Jade Mine, China
Authors: Liu Sixin , Liu Xintong , Meng Xu , Fu Lei , Lu Qi , Deng Li
Published: September 2018

Xiuyan Jade, produced in Xiuyan County, Liaoning Province, China is one of the four famous jade in China. King Jade, which is deemed the largest jade body of the world, was broken out from a hill. The local government planned to build a tourism site based on the jade culture there. The purpose of the investigation was to evaluate the stability of subsurface foundation, and the possible positions of mined-out zones to prevent the further rolling of the jade body. Cross-hole radar tomography is the key technique in the investigation. Conventional travel time and attenuation tomography based on ray tracing theory cannot provide high-resolution images because only a fraction of the measured information is used in the inversion. Full-waveform inversion (FWI) can provide high-resolution permittivity and conductivity images because it utilizes all the information provided by the radar signals. We deduce the gradient expression of the time-domain FWI with respect to the permittivity and conductivity using a method that is different from that of the previous work and realize the FWI algorithm that can simultaneously update the permittivity and conductivity by using the conjugate gradient method. Inverted results from synthetic data show that time-domain FWI can significantly improve the resolution compared with the ray-based tomogram methods. FWI can distinguish targets that are as small as one-half to one-third wavelength and the inverted physical values are closer to the real ones than those provided by the ray tracing method. We use the FWI algorithm to the field data measured at Xiuyan jade mine. Both the inverted permittivity and conductivity can comparably delineate four mined-out zones, which exhibit low-permittivity and low-conductivity characteristics. Furthermore, the locations of the interpreted mined-out zones are in good agreement with the existing mining channels recorded by geological data.
A Scene Recognition and Semantic Analysis Approach to Unhealthy Sitting Posture Detection during Screen-Reading
Authors: Min Weidong , Cui Hao , Han Qing , Zou Fangyuan
Published: September 2018

Behavior analysis through posture recognition is an essential research in robotic systems. Sitting with unhealthy sitting posture for a long time seriously harms human health and may even lead to lumbar disease, cervical disease and myopia. Automatic vision-based detection of unhealthy sitting posture, as an example of posture detection in robotic systems, has become a hot research topic. However, the existing methods only focus on extracting features of human themselves and lack understanding relevancies among objects in the scene, and henceforth fail to recognize some types of unhealthy sitting postures in complicated environments. To alleviate these problems, a scene recognition and semantic analysis approach to unhealthy sitting posture detection in screen-reading is proposed in this paper. The key skeletal points of human body are detected and tracked with a Microsoft Kinect sensor. Meanwhile, a deep learning method, Faster R-CNN, is used in the scene recognition of our method to accurately detect objects and extract relevant features. Then our method performs semantic analysis through Gaussian-Mixture behavioral clustering for scene understanding. The relevant features in the scene and the skeletal features extracted from human are fused into the semantic features to discriminate various types of sitting postures. Experimental results demonstrated that our method accurately and effectively detected various types of unhealthy sitting postures in screen-reading and avoided error detection in complicated environments. Compared with the existing methods, our proposed method detected more types of unhealthy sitting postures including those that the existing methods could not detect. Our method can be potentially applied and integrated as a medical assistance in robotic systems of health care and treatment.
Helicopter Test of a Strapdown Airborne Gravimetry System
Authors: Jensen Tim Enzlberger , Forsberg Rene
Published: September 2018

Airborne gravimetry from a helicopter has been a feasible tool since the 1990s, with gravimeters mounted on a gyro-stabilised platform. In contrast to fixed-wing aircrafts, the helicopter allows for a higher spatial resolution, since it can move slower and closer to the ground. In August 2016, a strapdown gravimetry test was carried out over the Jakobshavn Glacier in Greenland. To our knowledge, this was the first time that a strapdown system was used in a helicopter. The strapdown configuration is appealing because it is easily installed and requires no operation during flight. While providing additional information over the thickest part of the glacier, the survey was designed to assess repeatability both within the survey and with respect to profiles flown previously using a gyro-stabilised gravimeter. The system’s ability to fly at an altitude following the terrain, i.e., draped flying, was also tested. The accuracy of the gravity profiles was estimated to 2 mGal and a method for inferring the spatial resolution was investigated, yielding a half-wavelength spatial resolution of 4.5 km at normal cruise speed.