bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical and Theoretical Modeling of Low-Frequency Noise Behavior of Ultrathin Silicon-on-Insulator MOSFETs Aiming at Low-Voltage and Low-Energy Regime
Authors: Omura Yasuhisa
Published: December 2018

This paper theoretically revisits the low-frequency noise behavior of the inversion-channel silicon-on-insulator metal-oxide-semiconductor field-effect transistor (SOI MOSFET) and the buried-channel SOI MOSFET because the quality of both Si/SiO2 interfaces (top and bottom) should modulate the low-frequency fluctuation characteristics of both devices. It also addresses the low-frequency noise behavior of sub-100-nm channel SOI MOSFETs. We deepen the discussion of the low-frequency noise behavior in the subthreshold bias range in order to elucidate the device’s potential for future low-voltage and low-power applications. As expected, analyses suggest that the weak inversion channel near the top surface of the SOI MOSFET is strongly influenced by interface traps near the top surface of the SOI layer because the traps are not well shielded by low-density surface inversion carriers in the subthreshold bias range. Unexpectedly, we find that the buried channel is primarily influenced by interface traps near the top surface of the SOI layer, not by traps near the bottom surface of the SOI layer. This is not due to the simplified capacitance coupling effect. These interesting characteristics of current fluctuation spectral intensity are explained well by the theoretical models proposed here.
A Review of Automated Microinjection of Zebrafish Embryos
Authors: Zhao Yuliang , Sun Hui , Sha Xiaopeng , Gu Lijia , Zhan Zhikun , Li Wen
Published: December 2018

Cell microinjection is a technique of precise delivery of substances into cells and is widely used for studying cell transfection, signaling pathways, and organelle functions. Microinjection of the embryos of zebrafish, the third most important animal model, has become a very useful technique in bioscience. However, factors such as the small cell size, high cell deformation tendency, and transparent zebrafish embryo membrane make the microinjection process difficult. Furthermore, this process has strict, specific requirements, such as chorion softening, avoiding contacting the first polar body, and high-precision detection. Therefore, highly accurate control and detection platforms are critical for achieving the automated microinjection of zebrafish embryos. This article reviews the latest technologies and methods used in the automated microinjection of zebrafish embryos and provides a detailed description of the current developments and applications of robotic microinjection systems. The review covers key areas related to automated embryo injection, including cell searching and location, cell position and posture adjustment, microscopic visual servoing control, sensors, actuators, puncturing mechanisms, and microinjection.
Recent Advances and New Perspectives in Capillary Electrophoresis-Mass Spectrometry for Single Cell “Omics”
Authors: DeLaney Kellen , Sauer Christopher S. , Vu Nhu Q. , Li Lingjun
Published: December 2018

Accurate clinical therapeutics rely on understanding the metabolic responses of individual cells. However, the high level of heterogeneity between cells means that simply sampling from large populations of cells is not necessarily a reliable approximation of an individual cell’s response. As a result, there have been numerous developments in the field of single-cell analysis to address this lack of knowledge. Many of these developments have focused on the coupling of capillary electrophoresis (CE), a separation technique with low sample consumption and high resolving power, and mass spectrometry (MS), a sensitive detection method for interrogating all ions in a sample in a single analysis. In recent years, there have been many notable advancements at each step of the single-cell CE-MS analysis workflow, including sampling, manipulation, separation, and MS analysis. In each of these areas, the combined improvements in analytical instrumentation and achievements of numerous researchers have served to drive the field forward to new frontiers. Consequently, notable biological discoveries have been made possible by the implementation of these methods. Although there is still room in the field for numerous further advances, researchers have effectively minimized various limitations in detection of analytes, and it is expected that there will be many more developments in the near future.
Molecules that Inhibit Bacterial Resistance Enzymes
Authors: Liu Yuan , Li Ruichao , Xiao Xia , Wang Zhiqiang
Published: December 2018

Antibiotic resistance mediated by bacterial enzymes constitutes an unmet clinical challenge for public health, particularly for those currently used antibiotics that are recognized as “last-resort” defense against multidrug-resistant (MDR) bacteria. Inhibitors of resistance enzymes offer an alternative strategy to counter this threat. The combination of inhibitors and antibiotics could effectively prolong the lifespan of clinically relevant antibiotics and minimize the impact and emergence of resistance. In this review, we first provide a brief overview of antibiotic resistance mechanism by bacterial secreted enzymes. Furthermore, we summarize the potential inhibitors that sabotage these resistance pathways and restore the bactericidal activity of inactive antibiotics. Finally, the faced challenges and an outlook for the development of more effective and safer resistance enzyme inhibitors are discussed.
Substitution Effect on the Charge Transfer Processes in Organo-Imido Lindqvist-Polyoxomolybdate
Authors: Hermosilla-Ibáñez Patricio , Wrighton-Araneda Kerry , Cañón-Mancisidor Walter , Gutiérrez-Cutiño Marlen , Paredes-García Verónica , Venegas-Yazigi Diego
Published: December 2018

Two new aromatic organo-imido polyoxometalates with an electron donor triazole group ([n-Bu4N]2[Mo6O18NC6H4N3C2H2]) (1) and a highly conjugated fluorene ([n-Bu4N]2[Mo6O18NC13H9]) (2) have been obtained. The electrochemical and spectroscopic properties of several organo-imido systems were studied. These properties were analysed by the theoretical study of the redox potentials and by means of the excitation analysis, in order to understand the effect on the substitution of the organo-imido fragment and the effect of the interaction to a metal centre. Our results show a bathochromic shift related to the charge transfer processes induced by the increase of the conjugated character of the organic fragment. The cathodic shift obtained from the electrochemical studies reflects that the electronic communication and conjugation between the organic and inorganic fragments is the main reason of this phenomenon.
Catalytic Activity of Polynuclear vs. Dinuclear Aroylhydrazone Cu(II) Complexes in Microwave-Assisted Oxidation of Neat Aliphatic and Aromatic Hydrocarbons
Authors: Sutradhar Manas , Barman Tannistha Roy , Pombeiro Armando J. L. , Martins Luísa M.D.R.S.
Published: December 2018

One-dimensional (1D) polynuclear Cu(II) complex (1) derived from (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) is synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS, and single crystal X-ray crystallography. Its catalytic performance towards the solvent-free microwave-assisted peroxidative oxidation of aliphatic and aromatic hydrocarbons under mild conditions is compared with that of dinuclear Cu(II) complexes (2 and 3) of the same ligand, previously reported as antiproliferative agents. Polymer 1 exhibits the highest activity, either for the oxidation of cyclohexane (leading to overall yields, based on the alkane, of up to 39% of cyclohexanol and cyclohexanone) or towards the oxidation of toluene (selectively affording benzaldehyde up to a 44% yield), after 2 or 2.5 h of irradiation at 80 or 50 °C, respectively.
Green Corrosion Inhibitors from Natural Sources and Biomass Wastes
Authors: Marzorati Stefania , Verotta Luisella , Trasatti Stefano P.
Published: December 2018

Over the past decade, green chemistry has been emphasizing the importance of protecting the environment and human health in an economically beneficial manner aiming at avoiding toxins and reducing wastes. The field of metallic materials degradation, generally faced by using toxic compounds, found a fertile research field in green chemistry. In fact, the use of inhibitors is a well-known strategy when metal corrosion needs to be prevented, controlled, or retarded. Green inhibitors are biodegradable, ecologically acceptable and renewable. Their valorization expands possible applications in industrial fields other than ‘waste to energy’ in the perspective of circular economy. Although lot of experimental work has been done and many research papers have been published, the topic of green inhibitors is still an open issue. The great interest in the field expanded the research, resulting in high numbers of tested molecules. However, the most frequently adopted approaches are conventional and, hence, not suitable to fully characterize the potential efficacy of inhibitors. All the mentioned aspects are the object of the present review and are meant as a constructive criticism to highlight the weak points of the green inhibitors field as to re-evaluate the literature and address the future research in the field that still lacks rationalization.
Polycyclic Polyprenylated Acylphloroglucinol Derivatives from Hypericum acmosepalum
Authors: Wang Jiao , Shi Mengjiao , Wang Jiajia , Li Jin , Ji Tengfei
Published: December 2018

Hypericum acmosepalum belongs to the Hypericum genus of the Guttiferae family. The characteristic components in Hypericum are mainly a series of polycyclic polyprenylated acylphloroglucinols (PPAPs), flavonoids, and xanthones. Among them, the PPAPs have received much attention due to their novel structures and diverse pharmacological activities and have become hot spots in organic chemistry and medicinal chemistry. However, there are few reports about the chemical constituents of Hypericum acmosepalum at present, especially the PPAPs. This research is dedicated to the study of the air-dried aerial parts of Hypericum acmosepalum, which were extracted with 95% EtOH under reflux, then suspended and successively partitioned with petroleum ether and ethyl acetate. Five PPAP derivatives were obtained using various chromatographic techniques, and their structures were determined by NMR spectroscopic data, including two new phloroglucinol derivatives, hyperacmosin A (1) and hyperacmosin B (2). Those compounds were evaluated for their neuroprotective effect using two models.
Enhanced Antioxidant Activity for Apple Juice Fermented with Lactobacillus plantarum ATCC14917
Authors: Li Zhongxi , Teng Jing , Lyu Yilu , Hu Xiaoqian , Zhao Yueliang , Wang Mingfu
Published: December 2018

The present study examined the effect of Lactobacillus plantarum ATCC14917 fermentation on the chemical composition and antioxidant activity of apple juice. Apple juice was fermented and examined of its antioxidant activity using chemical models and cellular antioxidant assay. Furthermore, the chemical composition of fermented apple juice was characterized by LC-MS/MS. Lactobacillus plantarum ATCC14917 fermentation showed an increase in DPPH and ABTS radical scavenging activity as well as cellular antioxidant activity of apple juice. However, fermentation decreased the total phenolic and flavonoid content. Subsequent LC-MS/MS analysis of the phenolic profile indicated that the content of 5-O-caffeoylquinic acid (5-CQA), quercetin, and phloretin with strong antioxidant activity was increased significantly after fermentation. The modified phenolic composition may contribute to the increased antioxidant activity of fermented apple juice. Our findings showed that Lactobacillus plantarum ATCC14917 fermentation may be an efficient way to enhance the bioavailability of phenolic compounds and to protect cells from oxidative stress.
Immunomodulatory Effect of Vitamin D and Its Potential Role in the Prevention and Treatment of Type 1 Diabetes Mellitus—A Narrative Review
Authors: Rak Karolina , Bronkowska Monika
Published: December 2018

Type 1 diabetes mellitus is a chronic autoimmune disease associated with degeneration of pancreatic β-cells that results in an inability to produce insulin and the need for exogenous insulin administration. It is a significant global health problem as the incidence of this disorder is increasing worldwide. The causes are still poorly understood, although it certainly has genetic and environmental origins. Vitamin D formed profusely in the skin upon exposure to sunlight, as well as from dietary sources, exhibits an immunomodulatory effect based on gene transcription control. Indeed, vitamin D can downregulate mechanisms connected with adaptive immunity, induce immunological tolerance and decrease auto-aggression-related inflammation. These properties provide the basis for a preventive and therapeutic role of vitamin D. As many studies have demonstrated, appropriate supplementation with vitamin D reduces the risk of autoimmune diseases, including type 1 diabetes mellitus, and alleviates disease symptoms in patients. The aim of this narrative review is to present the molecular mechanisms for the vitamin D immunomodulatory effect as well as review human clinical studies on the use of vitamin D as adjuvant therapy in type 1 diabetes mellitus.
Steady Enhancement in Photovoltaic Properties of Fluorine Functionalized Quinoxaline-Based Narrow Bandgap Polymer
Authors: Wu Zhonglian , Jiang Huanxiang , Wang Xingzhu , Yan Lei , Zeng Wei , Wu Xiu-Gang , Zhuang Haiyu , Zhu Wen , Yang Renqiang
Published: December 2018

To investigate the influence of fluoride phenyl side-chains onto a quinoxaline (Qx) unit on the photovoltaic performance of the narrow bandgap (NBG) photovoltaic polymers, herein, two novel NBG copolymers, PBDTT-DTQx and PBDTT-DTmFQx, were synthesized and characterized. 2-ethylhexylthiothiophene-substituted benzodithiophene (BDTT), 2,3-diphenylquinoxaline (DQx) [or 2,3-bis(3-fluorophenyl)quinoxaline (DmFQx)] and 2-ethylhexylthiophene (T) were used as the electron donor (D) unit, electron-withdrawing acceptor (A) unit and π-bridge, respectively. Compared to non-fluorine substituted PBDTT-DTQx, fluoride PBDTT-DTmFQx exhibited a wide UV-Vis absorption spectrum and high hole mobility. An enhanced short-circuit current (Jsc) and fill factor (FF) simultaneously gave rise to favorable efficiencies in the polymer/PC71BM-based polymer solar cells (PSCs). Under the illumination of AM 1.5G (100 mW cm−2), a maximum power conversion efficiency (PCE) of 6.40% was achieved with an open-circuit voltage (Voc) of 0.87 V, a Jsc of 12.0 mA cm−2 and a FF of 61.45% in PBDTT-DTmFQx/PC71BM-based PSCs, while PBDTT-DTQx-based devices also exhibited a PCE of 5.43%. The excellent results obtained demonstrate that PBDTT-DTmFQx by fluorine atom engineering could be a promising candidate for organic photovoltaics.
Characterization, Variables, and Antioxidant Activity of the Maillard Reaction in a Fructose–Histidine Model System
Authors: Liu Pengli , Lu Xiaoming , Li Ningyang , Zheng Zhenjia , Qiao Xuguang
Published: December 2018

Fructose and its polysaccharides are widely found in fruits and vegetables, with the Maillard reaction of fructose affecting food quality. This study aimed to investigate the Maillard reaction of fructose using a fructose–histidine model system. The reaction process was characterized using fluorescence spectroscopy and ultraviolet spectroscopy. The effects of temperature, initial reactant concentration, initial fructose concentration, initial histidine concentration, and initial pH value on the different stages of the Maillard reaction were studied. Reactant reduction, ultraviolet and fluorescence spectra, acetic acid content, 5-hydroxymethylfurfural (5-HMF) content, and browning intensity were evaluated. The results showed that increasing the temperature and reactant concentration promoted the condensation reaction of fructose and amino acid in the early stage, the formation of intermediate products with ultraviolet absorption and fluorescence in the intermediate stage, and the formation of pigment in the final stage. The 5-HMF concentration decreased with increasing histidine concentration and initial pH value. Changes in the shape of ultraviolet and fluorescence spectra showed that the initial pH value affected not only the reaction rate, but also the intermediate product types. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rate of the Maillard reaction products increased with increasing temperature, reactant concentration, and initial pH value.
Site-directed Mutagenesis of a β-Glycoside Hydrolase from Lentinula edodes
Authors: Chen Jing-Jing , Liang Xiao , Chen Tian-Jiao , Yang Jin-Ling , Zhu Ping
Published: December 2018

The β-glycoside hydrolases (LXYL-P1−1 and LXYL-P1−2) from Lentinula edodes (strain M95.33) can specifically hydrolyze 7-β-xylosyl-10-deacetyltaxol (XDT) to form 10-deacetyltaxol for the semi-synthesis of Taxol. Our previous study showed that both the I368T mutation in LXYL-P1−1 and the T368E mutation in LXYL-P1−2 could increase the enzyme activity, which prompted us to investigate the effect of the I368E mutation on LXYL-P1−1 activity. In this study, the β-xylosidase and β-glucosidase activities of LXYL-P1−1I368E were 1.5 and 2.2 times higher than those of LXYL-P1−1. Most importantly, combination of I368E and V91S exerted the cumulative effects on the improvement of the enzyme activities and catalytic efficiency. The β-xylosidase and β-glucosidase activities of the double mutant LXYL-P1−1V91S/I368E were 3.2 and 1.7-fold higher than those of LXYL-P1−1I368E. Similarly, the catalytic efficiency of LXYL-P1−1V91S/I368E on 7-β-xylosyl-10-deacetyltaxol was 1.8-fold higher than that of LXYL-P1−1I368E due to the dramatic increase in the substrate affinity. Molecular docking results suggest that the V91S and I368E mutation might positively promote the interaction between enzyme and substrate through altering the loop conformation near XDT and increasing the hydrogen bonds among Ser91, Trp301, and XDT. This study lays the foundation for exploring the relationship between the structure and function of the β-glycoside hydrolases.
Effects of Ultrasonic Dispersion Energy on the Preparation of Amorphous SiO2 Nanomaterials for In Vitro Toxicity Testing
Authors: Wiemann Martin , Vennemann Antje , Stintz Michael , Retamal Marín Rodrigo R. , Babick Frank , Lindner Gottlieb-Georg , Schuster Tobias B. , Brinkmann Ulrich , Krueger Nils
Published: December 2018

Synthetic amorphous silica (SAS) constitute a large group of industrial nanomaterials (NM). Based on their different production processes, SAS can be distinguished as precipitated, fumed, gel and colloidal. The biological activity of SAS, e.g., cytotoxicity or inflammatory potential in the lungs is low but has been shown to depend on the particle size, at least for colloidal silica. Therefore, the preparation of suspensions from highly aggregated or agglomerated SAS powder materials is critical. Here we analyzed the influence of ultrasonic dispersion energy on the biologic activity of SAS using NR8383 alveolar macrophage (AM) assay. Fully characterized SAS (7 precipitated, 3 fumed, 3 gel, and 1 colloidal) were dispersed in H2O by stirring and filtering through a 5 µm filter. Aqueous suspensions were sonicated with low or high ultrasonic dispersion (USD) energy of 18 or 270 kJ/mL, respectively. A dose range of 11.25–90 µg/mL was administered to the AM under protein-free conditions to detect particle-cell interactions without the attenuating effect of proteins that typically occur in vivo. The release of lactate dehydrogenase (LDH), glucuronidase (GLU), and tumor necrosis factor α (TNF) were measured after 16 h. Hydrogen peroxide (H2O2) production was assayed after 90 min. The overall pattern of the in vitro response to SAS (12/14) was clearly dose-dependent, except for two SAS which showed very low bioactivity. High USD energy gradually decreased the particle size of precipitated, fumed, and gel SAS whereas the low adverse effect concentrations (LOECs) remained unchanged. Nevertheless, the comparison of dose-response curves revealed slight, but uniform shifts in EC50 values (LDH, and partially GLU) for precipitated SAS (6/7), gel SAS (2/3), and fumed SAS (3/3). Release of TNF changed inconsistently with higher ultrasonic dispersion (USD) energy whereas the induction of H2O2 was diminished in all cases. Electron microscopy and energy dispersive X-ray analysis showed an uptake of SAS into endosomes, lysosomes, endoplasmic reticulum, and different types of phagosomes. The possible effects of different uptake routes are discussed. The study shows that the effect of increased USD energy on the in vitro bioactivity of SAS is surprisingly small. As the in vitro response of AM to different SAS is highly uniform, the production process per se is of minor relevance for toxicity.
Natural Rubber Nanocomposites: A Review
Authors: Bokobza Liliane
Published: December 2018

This paper reviews studies carried out on natural rubber filled with nanofillers such as spherical silica particles (generated by the sol gel reaction), clays and carbon nanostructures. It is shown that the mechanical response of NR is influenced by several parameters including the processing conditions, the state of filler dispersion, the polymer-filler interactions and the filler morphological aspects. Even if the sol gel process conducted in vulcanized rubber yields almost ideal dispersions, rod-shaped particles such as clay, carbon fibers or carbon nanotubes are by far more efficient in terms of mechanical reinforcement on account of their anisotropic character and their ability to orientate in the direction of stretch. The efficiency of layered fillers such as clays or graphitic structures clearly depends on the way they are dispersed (exfoliated) in the rubber. Complete exfoliation still remains difficult to achieve which limits the tremendous nanoreinforcement expected from a single layer of clay or graphite. In all cases, the onset of crystallization is observed at a lower strain value than that of the unfilled matrix due to strain amplification effects.
Interplay between Nutrition and Hearing Loss: State of Art
Authors: Puga Ana M. , Pajares María A. , Varela-Moreiras Gregorio , Partearroyo Teresa
Published: December 2018

Hearing loss has been recently ranked as the fifth leading cause of years lived with disability, ahead of many other chronic diseases such as diabetes, dementia, or chronic obstructive pulmonary disease. Moreover, according to the World Health Organization, moderate-to-profound hearing loss affects about 466 million people worldwide. Its incidence varies in each population segment, affecting approximately 10% of children and increasing to 30% of the population over 65 years. However, hearing loss receives still very limited research funding and public awareness. This sensory impairment is caused by genetic and environmental factors, and among the latter, the nutritional status has acquired relevance due its association to hearing loss detected in recent epidemiological studies. Several experimental models have proved that the onset and progression of hearing loss are closely linked to the availability of nutrients and their metabolism. Here, we have reviewed studies focused on nutrient effects on auditory function. These studies support the potential of nutritional therapy for the protection against hearing loss progression, which is especially relevant to the aging process and related quality of life.
Serum Trace Elements and Their Associations with Breast Cancer Subgroups in Korean Breast Cancer Patients
Authors: Choi Rihwa , Kim Min-Ji , Sohn Insuk , Kim Serim , Kim Isaac , Ryu Jai Min , Choi Hee Jun , Kim Jae-Myung , Lee Se Kyung , Yu Jonghan , Kim Seok Won , Nam Seok Jin , Lee Jeong Eon , Lee Soo-Youn
Published: December 2018

The relationships between serum levels of trace elements and breast cancer remain relatively unknown. In this study, we investigate serum levels of seven trace elements in Korean breast cancer patients compared to controls without breast cancer. Serum trace element levels were determined using inductively coupled plasma mass spectrometry in Korean breast cancer patients before initiation of breast cancer treatment. Korean females without breast cancer served as a control group. Trace element levels were measured in the discovery cohort (n = 287) and were validated in an independent cohort (n = 142). We further investigated possible associations between trace element levels and the presence of lymph node metastasis, distant metastasis, or triple-negative breast cancer among breast cancer patients in subgroup analyses. Serum manganese and molybdenum levels were significantly higher (p < 0.05) in breast cancer patients than in controls. Serum copper levels were significantly higher in breast cancer patients with distant metastasis, while selenium levels were significantly lower. Other trace elements were neither significantly different between breast cancer patients and controls nor between subgroups of breast cancer patients. Our study provides insights about the potential roles and impacts of trace elements through an assessment of the associations between trace elements and breast cancer.
Graphene Oxide Functional Nanohybrids with Magnetic Nanoparticles for Improved Vectorization of Doxorubicin to Neuroblastoma Cells
Authors: Lerra Luigi , Farfalla Annafranca , Sanz Beatriz , Cirillo Giuseppe , Vittorio Orazio , Voli Florida , Le Grand Marion , Curcio Manuela , Nicoletta Fiore Pasquale , Dubrovska Anna , Hampel Silke , Iemma Francesca , Goya Gerardo F.
Published: December 2018

With the aim to obtain a site-specific doxorubicin (DOX) delivery in neuroblastoma SH-SY5Y cells, we designed an hybrid nanocarrier combining graphene oxide (GO) and magnetic iron oxide nanoparticles (MNPs), acting as core elements, and a curcumin–human serum albumin conjugate as functional coating. The nanohybrid, synthesized by redox reaction between the MNPs@GO system and albumin bioconjugate, consisted of MNPs@GO nanosheets homogeneously coated by the bioconjugate as verified by SEM investigations. Drug release experiments showed a pH-responsive behavior with higher release amounts in acidic (45% at pH 5.0) vs. neutral (28% at pH 7.4) environments. Cell internalization studies proved the presence of nanohybrid inside SH-SY5Y cytoplasm. The improved efficacy obtained in viability assays is given by the synergy of functional coating and MNPs constituting the nanohybrids: while curcumin moieties were able to keep low DOX cytotoxicity levels (at concentrations of 0.44–0.88 µM), the presence of MNPs allowed remote actuation on the nanohybrid by a magnetic field, increasing the dose delivered at the target site.
Flexural Behavior and Fracture Mechanisms of Short Carbon Fiber Reinforced Polyether-Ether-Ketone Composites at Various Ambient Temperatures
Authors: Zheng Bing , Deng Tianzhengxiong , Li Maoyuan , Huang Zhigao , Zhou Huamin , Li Dequn
Published: December 2018

In this study, the flexural behavior and fracture mechanisms of short carbon fiber reinforced polyether-ether-ketone (SCFR/PEEK) composites at various ambient temperatures were investigated. First, the crystallinity and glass transition temperature (Tg) of PEEK and SCFR/PEEK were analyzed by differential scanning calorimetry analysis and dynamic mechanical analysis tests, respectively. The addition of SCFs increases the Tg but does not change the crystallinity of the PEEK matrix. Then, the three-point flexural tests of PEEK and SCFR/PEEK were performed over the temperature range of 20 to 235 °C, and the temperature-dependencies of the flexural properties of PEEK and SCFR/PEEK were discussed in detail. Finally, the microstructure of SCFR/PEEK was observed using a digital microscope and scanning electron microscope. The results show that the tension crack occurs first, and the crack extends upward leading to the shear crack and compression crack at room temperature. The fracture of SCFR/PEEK is mainly due to the extraction and rupture of SCFs. At high temperatures (above Tg), the tension crack and compression crack both occur, and the strong ductility of the matrix prevents the generation of shear crack. The fracture of SCFR/PEEK is mainly due to the rotation and extraction of SCFs, while the SCFs rupture plays a minor role.
A Semi-Analytical Model to Predict Infusion Time and Reinforcement Thickness in VARTM and SCRIMP Processes
Authors: Rubino Felice , Carlone Pierpaolo
Published: December 2018

In liquid composite molding processes, such as resin transfer molding (RTM) and vacuum assisted resin transfer molding (VARTM), the resin is drawn through fiber preforms in a closed mold by an induced pressure gradient. Unlike the RTM, where a rigid mold is employed, in VARTM, a flexible bag is commonly used as the upper-half mold. In this case, fabric deformation can take place during the impregnation process as the resin pressure inside the preform changes, resulting in continuous variations of reinforcement thickness, porosity, and permeability. The proper approach to simulate the resin flow, therefore, requires coupling deformation and pressure field making the process modeling more complex and computationally demanding. The present work proposes an efficient methodology to add the effects of the preform compaction on the resin flow when a deformable porous media is considered. The developed methodology was also applied in the case of Seeman’s Composite Resin Infusion Molding Process (SCRIMP). Numerical outcomes highlighted that preform compaction significantly affects the resin flow and the filling time. In particular, the more compliant the preform, the more time is required to complete the impregnation. On the other hand, in the case of SCRIMP, the results pointed out that the resin flow is mainly ruled by the high permeability network.
The Investigation of the Seebeck Effect of the Poly(3,4-Ethylenedioxythiophene)-Tosylate with the Various Concentrations of an Oxidant
Authors: Kim Joon-Soo , Jang Woongsik , Wang Dong Hwan
Published: December 2018

Poly(3,4-ethylenedioxythiophene)-tosylate (PEDOT-Tos) can be synthesized through an in situ polymerization and doping process with iron(III) p-toluenesulfonate hexahydrate as an oxidant. Both the Seebeck coefficient and the electrical conductivity were modified by varying the concentration of the oxidant. We investigated the effects of varying the concentration of the oxidant on the particle sizes and doping (oxidation) levels of PEDOT-Tos for thermoelectric applications. We demonstrated that an increase in the oxidant enabled an expansion of the particle sizes and the doping levels of the PEDOT-Tos. The modification of the doping levels by the concentration of the oxidant can provide another approach for having an optimal power factor for thermoelectric applications. De-doping of PEDOTs by reduction agents has been generally investigated for changing its oxidation levels. In this study, we investigated the effect of the concentration of the oxidant of PEDOT-Tos on the oxidation levels, the electrical conductivities and the Seebeck coefficients. As loading the oxidant of PEDOT-Tos, the Seebeck coefficient was compromised, while the electrical conductivity increased.
Preparation and Application of Conductive Polyaniline-Coated Thermally Expandable Microspheres
Authors: Jiao Shou-Zheng , Sun Zhi-Cheng , Li Fu-Rong , Yan Mei-Jia , Cao Mei-Juan , Li Dong-Sheng , Liu Yan , Li Lu-Hai
Published: December 2018

The thermally expandable microspheres (TEMs) were prepared through suspension polymerization with acrylonitrile (AN), methyl methacrylate (MMA) and methyl acrylate (MA) as the main monomers. Simultaneously, iso-pentane, n-hexane, iso-octane and other low-boiling hydrocarbons were prepared as blowing agents under two conditions, including high-pressure nitrogen and atmospheric conditions. The above physical foaming microspheres have a core-shell structure and excellent foaming effects. A layer of polyaniline (PANI) was deposited on the surface of the prepared TEMs by emulsion polymerization to obtain conductive and heat-expandable microspheres. Afterwards, the foaming ink was prepared by mixing the conductive TEMs and water-based ink. Finally, a conductive three-dimensional picture was obtained by screen-printing technology. This paper specifically focuses on the effects of particle size, morphology and the thermal expansion properties of the microspheres. The present research methods expect to obtain microspheres with a high foaming ratio, uniform particle size and antistatic properties, which may be applied to physical foaming ink.
The Structure and Mechanical Properties of the UHMWPE Films Modified by the Mixture of Graphene Nanoplates with Polyaniline
Authors: Dayyoub Tarek , Maksimkin Aleksey V. , Kaloshkin Sergey , Kolesnikov Evgeniy , Chukov Dilus , Dyachkova Tat’yana P. , Gutnik Irina
Published: December 2018

Highly oriented UHMWPE films were reinforced with functionalized graphene nanoplates (GNP). GNP was functionalized by deposition of polyaniline (PANI) on the GNP surface. The structure of GNP/PANI was studied by Raman spectroscopy, and the structure of xerogels and films based on UHMWPE was studied by DSC and SEM. PANI promotes the reduction of the GNP aggregation in the UHMWPE matrix and increases the degree of crystallinity due to heterogeneous crystallization. The new lamellar crystal structure has a high drawability. The highest value of the tensile strength 1330 MPa (an increase of 45%) was obtained with a filler content of 2 wt % GNP/PANI, and the highest value of Young’s modulus 41 GPa (an increase of 32%) was obtained with a filler content of 1 wt % GNP/PANI. The effect of GNP with PANI fillers on the dynamic mechanical properties of the UHMWPE films was discussed.
Dense Semantic Labeling with Atrous Spatial Pyramid Pooling and Decoder for High-Resolution Remote Sensing Imagery
Authors: Wang Yuhao , Liang Binxiu , Ding Meng , Li Jiangyun
Published: December 2018

Dense semantic labeling is significant in high-resolution remote sensing imagery research and it has been widely used in land-use analysis and environment protection. With the recent success of fully convolutional networks (FCN), various types of network architectures have largely improved performance. Among them, atrous spatial pyramid pooling (ASPP) and encoder-decoder are two successful ones. The former structure is able to extract multi-scale contextual information and multiple effective field-of-view, while the latter structure can recover the spatial information to obtain sharper object boundaries. In this study, we propose a more efficient fully convolutional network by combining the advantages from both structures. Our model utilizes the deep residual network (ResNet) followed by ASPP as the encoder and combines two scales of high-level features with corresponding low-level features as the decoder at the upsampling stage. We further develop a multi-scale loss function to enhance the learning procedure. In the postprocessing, a novel superpixel-based dense conditional random field is employed to refine the predictions. We evaluate the proposed method on the Potsdam and Vaihingen datasets and the experimental results demonstrate that our method performs better than other machine learning or deep learning methods. Compared with the state-of-the-art DeepLab_v3+ our model gains 0.4% and 0.6% improvements in overall accuracy on these two datasets respectively.
Digital Surface Model Interpolation Based on 3D Mesh Models
Authors: Kim Soohyeon , Rhee Sooahm , Kim Taejung
Published: December 2018

A digital surface model (DSM) is an important geospatial infrastructure used in various fields. In this paper, we deal with how to improve the quality of DSMs generated from stereo image matching. During stereo image matching, there are outliers due to mismatches, and non-matching regions due to match failure. Such outliers and non-matching regions have to be corrected accurately and efficiently for high-quality DSM generation. This process has been performed by applying a local distribution model, such as inverse distance weight (IDW), or by forming a triangulated irregular network (TIN). However, if the area of non-matching regions is large, it is not trivial to interpolate elevation values using neighboring cells. In this study, we proposed a new DSM interpolation method using a 3D mesh model, which is more robust to outliers and large holes. We compared mesh-based DSM with IDW-based DSM and analyzed the characteristics of each. The accuracy of the mesh-based DSM was a 2.80 m root mean square error (RMSE), while that for the IDW-based DSM was 3.22 m. While the mesh-based DSM successfully removed empty grid cells and outliers, the IDW-based DSM had sharper object boundaries. Because of the nature of surface reconstruction, object boundaries appeared smoother on the mesh-based DSM. We further propose a method of integrating the two DSMs. The integrated DSM maintains the sharpness of object boundaries without significant accuracy degradation. The contribution of this paper is the use of 3D mesh models (which have mainly been used for 3D visualization) for efficient removal of outliers and non-matching regions without a priori knowledge of surface types.
Two-Parameter Elliptical Fitting Method for Short-Cavity Fiber Fabry–Perot Sensor Interrogation
Authors: Zhang Xiongxing , Wang Wei , Chen Haibin , Tang Ying , Ma Zhibo , Wang Kening
Published: December 2018

To solve the cavity interrogation problem of short cavity fiber Fabry–Perot sensors in white light spectral interrogation with amplified spontaneous emissions (ASEs) as the white light sources, a data processing method, using an improved elliptical fitting equation with only two undetermined coefficients, is proposed. Based on the method, the cavity length of a fiber Fabry–Perot sensor without a complete reflection spectrum period in the frequency domain can be interrogated with relatively high resolution. Extrinsic fiber Fabry–Perot air-gap sensors with cavity lengths less than 30 μm are used to experimentally verify the method, and are successfully interrogated with an accuracy better than 0.55%.
Wavelet-Based Demodulation of Multimode Etched Fiber Bragg Grating Refractive Index Sensor
Authors: Ayupova Takhmina , Sypabekova Marzhan , Molardi Carlo , Bekmurzayeva Aliya , Shaimerdenova Madina , Dukenbayev Kanat , Tosi Daniele
Published: December 2018

Etched fiber Bragg grating (EFBG)-based sensors are used as evanescent field sensors for refractive index detection. When the fiber thickness is thin and the refractive index sensitivity increases, the number of propagating modes increases, resulting in a spectral enlargement that complicates the interrogation of the sensor. In this work, we present a method to analyze the spectrum of a multimode etched fiber Bragg grating (MMEFBG) in the wavelet domain, which analyzes the amount of spectral density independently from the peak reflectivity value. The proposed interrogation method permits defining the integral of the spectral density as a novel and unconventional estimator. With respect to the conventional estimators based on wavelength shift, this estimator can better exploit the larger amount of information given by the spectral enlargement typical of multimode behavior. Results were obtained by etching an MMEFBG in hydrofluoric acid and using water/sucrose mixtures to evaluate the refractive index sensitivity, validating the interrogation method.
Dynamic Barrier Coverage in a Wireless Sensor Network for Smart Grids
Authors: Fan Fei , Ji Qiaoling , Wu Gongping , Wang Man , Ye Xuhui , Mei Quanjie
Published: December 2018

The development of engineering technology such as inspection robots (IR) for transmission lines and wireless sensor networks (WSN) are widely used in the field of smart grid monitoring. However, how to integrate inspection robots into wireless sensor networks is still a great challenge to form an efficient dynamic monitoring network for transmission lines. To address this problem, a dynamic barrier coverage (DBC) method combining inspection robot and wireless sensor network (WSN) is proposed to realize a low-cost, energy-saving and dynamic smart grid-oriented sensing system based on mobile wireless sensor network. To establish an effective smart grid monitoring system, this research focuses on the design of an effective and safe dynamic network coverage and network nodes deployment method. Multiple simulation scenarios are implemented to explore the variation of network performance with different parameters. In addition, the dynamic barrier coverage method for the actual scene of smart grid monitoring considers the balance between network performance and financial costs.
Adaptive Linear Quadratic Attitude Tracking Control of a Quadrotor UAV Based on IMU Sensor Data Fusion
Authors: Koksal N. , Jalalmaab M. , Fidan B.
Published: December 2018

In this paper, an infinite-horizon adaptive linear quadratic tracking (ALQT) control scheme is designed for optimal attitude tracking of a quadrotor unmanned aerial vehicle (UAV). The proposed control scheme is experimentally validated in the presence of real-world uncertainties in quadrotor system parameters and sensor measurement. The designed control scheme guarantees asymptotic stability of the close-loop system with the help of complete controllability of the attitude dynamics in applying optimal control signals. To achieve robustness against parametric uncertainties, the optimal tracking solution is combined with an online least squares based parameter identification scheme to estimate the instantaneous inertia of the quadrotor. Sensor measurement noises are also taken into account for the on-board Inertia Measurement Unit (IMU) sensors. To improve controller performance in the presence of sensor measurement noises, two sensor fusion techniques are employed, one based on Kalman filtering and the other based on complementary filtering. The ALQT controller performance is compared for the use of these two sensor fusion techniques, and it is concluded that the Kalman filter based approach provides less mean-square estimation error, better attitude estimation, and better attitude control performance.
A Novel Vehicle Detection Method Based on the Fusion of Radio Received Signal Strength and Geomagnetism
Authors: Lou Liangliang , Zhang Jinyi , Xiong Yong , Jin Yanliang
Published: December 2018

A geomagnetic signal blind zone exists between the front and rear axle of high-chassis vehicle such as trucks and buses, which leads to multiple-detection problem in detecting those vehicles running at low speed on roads or error-detection problem in the case of the stopping position of the vehicle is not standard when waiting for the traffic light to change. In order to improve the detection accuracy of any type of vehicle running at any speed, a novel two-sensors data fusion vehicle detection method through combining received signal strength from radio stations with geomagnetism around vehicles is designed and verified in the paper. Experimental results show that the accuracy of our proposed method can reach 95.4% and traditional single magnetism-based detection method was only 83.4% in the detection of high-chassis vehicles.
Implementation of Virtual Sensors for Monitoring Temperature in Greenhouses Using CFD and Control
Authors: Guzmán Cesar H. , Carrera José L. , Durán Héctor A. , Berumen Javier , Ortiz Arturo A. , Guirette Omar A. , Arroyo Angélica , Brizuela Jorge A. , Gómez Fabio , Blanco Andrés , Azcaray Héctor R. , Hernández Marlen
Published: December 2018

Virtual sensing is crucial in order to provide feasible and economical alternatives when physical measuring instruments are not available. Developing model-based virtual sensors to calculate real-time information at each targeted location is a complex endeavor in terms of sensing technology. This paper proposes a new approach for model-based virtual sensor development using computational fluid dynamics (CFD) and control. Its main objective is to develop a three-dimensional (3D) real-time simulator using virtual sensors to monitor the temperature in a greenhouse. To conduct this study, a small-scale greenhouse was designed, modeled, and fabricated. The controller was based on the convection heat transfer equation under specific assumptions and conditions. To determine the temperature distribution in the greenhouse, a CFD analysis was conducted. Only one well-calibrated and controlled physical sensor (temperature reference) was enough for the CFD analysis. After processing the result that was obtained from the real sensor output, each virtual sensor had learned the associative transfer function that estimated the output from given input data, resulting in a 3D real-time simulator. This study has demonstrated, for the first time, that CFD analysis and a control strategy can be combined to obtain system models for monitoring the temperature in greenhouses. These findings suggest that, generally, virtual sensing can be applied in large greenhouses for monitoring the temperature using a 3D real-time simulator.
How Do Technological Skills Improve Reverse Logistics? The Moderating Role of Top Management Support in Information Technology Use and Innovativeness
Authors: García-Sánchez Encarnación , Guerrero-Villegas Jaime , Aguilera-Caracuel Javier
Published: December 2018

The purpose of this paper is to explore the influence of human resource management on reverse logistics (RL) in the context of high-tech firms. Using the resource-based view of the firm, we analyzedthe effect of employees’ technological skills on RL. The study also investigated whether top management support (TMS) for information technology (IT) and innovativeness moderate this relationship. We collected data from European high-tech firms from May to September 2010, obtaining 160 responses representing a 17.7% response rate. Multivariate regressions were used to assess all of the relations established. The results indicated that technological skills have direct and positive effects on RL in high tech-firms. The authors also report that both TMS for IT and innovativeness act as positive moderators in the relationship between technological skills and RL. This study suggests the importance of considering two important organizational variables that enhance the effect of technological skills on RL in high-tech firms. First, using TMS for IT not only provides tangible resources but also strongly supports employees’ technological development in RL. Second, a high level of firm innovativeness leads high-tech firms to create the right conditions to take advantage of their technological skills to improve their RL. Moreover, theresults indicate the contingent role of innovativeness and TMS for IT use in the relationship between technological skills and RL.
Optimal Management of a Hybrid Renewable Energy System Coupled with a Membrane Bioreactor Using Enviro-Economic and Power Pinch Analyses for Sustainable Climate Change Adaption
Authors: Hoang Tuan-Viet , Ifaei Pouya , Nam Kijeon , Rashidi Jouan , Hwangbo Soonho , Oh Jong-Min , Yoo ChangKyoo
Published: December 2018

This study proposed an optimal hybrid renewable energy system (HRES) to sustainably meet the dynamic electricity demand of a membrane bioreactor. The model-based HRES consists of solar photovoltaic panels, wind turbines, and battery banks with grid connectivity. Three scenarios, 101 sub-scenarios, and three management cases were defined to optimally design the system using a novel dual-scale optimization approach. At the system scale, the power-pinch analysis was applied to minimize both the size of components and the outsourced needed electricity (NE) from Vietnam’s electrical grid. At a local-scale, economic and environmental models were integrated, and the system was graphically optimized using a novel objective function, combined enviro-economic costs (CEECs). The results showed that the optimal CEECs were $850,710/year, $1,030,628/year, and $1,693,476/year for the management cases under good, moderate, and unhealthy air qualities, respectively. The smallest CEEC was obtained when 47% of the demand load of the membrane bioreactor was met using the HRES and the rest was supplied by the grid, resulting in 6,800,769 kg/year of CO2 emissions.