bluuebunny/crossref_metadata_2025 huggingface dataset:
Disruption of Autolysis in Bacillus subtilis using TiO2 Nanoparticles
Authors: McGivney Eric , Han Linchen , Avellan Astrid , VanBriesen Jeanne , Gregory Kelvin B.
Published: March 2017

In contrast to many nanotoxicity studies where nanoparticles (NPs) are observed to be toxic or reduce viable cells in a population of bacteria, we observed that increasing concentration of TiO2 NPs increased the cell survival of Bacillus subtilis in autolysis-inducing buffer by 0.5 to 5 orders of magnitude over an 8 hour exposure. Molecular investigations revealed that TiO2 NPs prevent or delay cell autolysis, an important survival and growth-regulating process in bacterial populations. Overall, the results suggest two potential mechanisms for the disruption of autolysis by TiO2 NPs in a concentration dependent manner: (i) directly, through TiO2 NP deposition on the cell wall, delaying the collapse of the protonmotive-force and preventing the onset of autolysis; and (ii) indirectly, through adsorption of autolysins on TiO2 NP, limiting the activity of released autolysins and preventing further lytic activity. Enhanced darkfield microscopy coupled to hyperspectral analysis was used to map TiO2 deposition on B. subtilis cell walls and released enzymes, supporting both mechanisms of autolysis interference. The disruption of autolysis in B. subtilis cultures by TiO2 NPs suggests the mechanisms and kinetics of cell death may be influenced by nano-scale metal oxide materials, which are abundant in natural systems.
Partitioning of red blood cell aggregates in bifurcating microscale flows
Authors: Kaliviotis E. , Sherwood J. M. , Balabani S.
Published: March 2017

Microvascular flows are often considered to be free of red blood cell aggregates, however, recent studies have demonstrated that aggregates are present throughout the microvasculature, affecting cell distribution and blood perfusion. This work reports on the spatial distribution of red blood cell aggregates in a T-shaped bifurcation on the scale of a large microvessel. Non-aggregating and aggregating human red blood cell suspensions were studied for a range of flow splits in the daughter branches of the bifurcation. Aggregate sizes were determined using image processing. The mean aggregate size was marginally increased in the daughter branches for a range of flow rates, mainly due to the lower shear conditions and the close cell and aggregate proximity therein. A counterintuitive decrease in the mean aggregate size was apparent in the lower flow rate branches. This was attributed to the existence of regions depleted by aggregates of certain sizes in the parent branch, and to the change in the exact flow split location in the T-junction with flow ratio. The findings of the present investigation may have significant implications for microvascular flows and may help explain why the effects of physiological RBC aggregation are not deleterious in terms of in vivo vascular resistance.
Modulated CH3NH3PbI3−xBrx film for efficient perovskite solar cells exceeding 18%
Authors: Tu Yongguang , Wu Jihuai , Lan Zhang , He Xin , Dong Jia , Jia Jinbiao , Guo Panfeng , Lin Jianming , Huang Miaoliang , Huang Yunfang
Published: March 2017

The organic-inorganic lead halide perovskite layer is a crucial factor for the high performance perovskite solar cell (PSC). We introduce CH3NH3Br in the precursor solution to prepare CH3NH3PbI3−xBrx hybrid perovskite, and an uniform perovskite layer with improved crystallinity and apparent grain contour is obtained, resulting in the significant improvement of photovoltaic performance of PSCs. The effects of CH3NH3Br on the perovskite morphology, crystallinity, absorption property, charge carrier dynamics and device characteristics are discussed, and the improvement of open circuit voltage of the device depended on Br doping is confirmed. Based on above, the device based on CH3NH3PbI2.86Br0.14 exhibits a champion power conversion efficiency (PCE) of 18.02%. This study represents an efficient method for high-performance perovskite solar cell by modulating CH3NH3PbI3−xBrx film.
An integrated analysis based on transcriptome and proteome reveals deastringency-related genes in CPCNA persimmon
Authors: Chen Wenxing , Xiong Yalou , Xu Liqing , Zhang Qinglin , Luo Zhengrong
Published: March 2017

Persimmon fruits accumulate a large amount of proanthocyanidins (PAs) during development. PAs cause a dry or puckering sensation due to its astringency. Pollination constant and non-astringent (PCNA) persimmon fruits can lose astringency during fruit ripening. However, little is known about the mechanism of natural de-astringency of Chinese PCNA (CPCNA). To gain insight into the molecular events of CPCNA natural de-astringency, we used mRNA-seq and iTRAQ-based quantitative proteomic analysis to measure changes in genes and proteins expression at two key stages of natural astringency removal (i.e. 10 and 20 weeks after bloom) and water-treated (i.e. 40 °C·12 h) de-astringency fruits. Our analyses show that the three predominantly process in CPCNA de-astringency: (1) water treatment strongly up-regulates glycolysis/acetaldehyde metabolism, (2) expression of genes/proteins involved in PA biosynthetic pathway was remarkably reduced in natural and water-treated de-astringency, (3) sugar metabolism and ethylene related pathway were quite abundant in natural de-astringency. We also found ethylene-related TFs were quite abundant in natural de-astringency, followed by WRKY and NAC transcription factors. These results provide an initial understanding of the predominantly biological processes underlying the natural de-astringency and “coagulation effect” in CPCNA.
Differential Proteomic Analysis by iTRAQ Reveals the Mechanism of Pyropia haitanensis Responding to High Temperature Stress
Authors: Shi Jianzhi , Chen Yuting , Xu Yan , Ji Dehua , Chen Changsheng , Xie Chaotian
Published: March 2017

Global warming increases sea temperature and leads to high temperature stress, which affects the yield and quality of Pyropia haitanensis. To understand the molecular mechanisms underlying high temperature stress in a high temperature tolerance strain Z-61, the iTRAQ technique was employed to reveal the global proteomic response of Z-61 under different durations of high temperature stress. We identified 151 differentially expressed proteins and classified them into 11 functional categories. The 4 major categories of these are protein synthesis and degradation, photosynthesis, defense response, and energy and carbohydrate metabolism. These findings indicated that photosynthesis, protein synthesis, and secondary metabolism are inhibited by heat to limit damage to a repairable level. As time progresses, misfolded proteins and ROS accumulate and lead to the up-regulation of molecular chaperones, proteases, and antioxidant systems. Furthermore, to cope with cells injured by heat, PCD works to remove them. Additionally, sulfur assimilation and cytoskeletons play essential roles in maintaining cellular and redox homeostasis. These processes are based on signal transduction in the phosphoinositide pathway and multiple ways to supply energy. Conclusively, Z-61 establishes a new steady-state balance of metabolic processes and survives under higher temperature stress.
Alteration of osteoblast arrangement via direct attack by cancer cells: New insights into bone metastasis
Authors: Kimura Yumi , Matsugaki Aira , Sekita Aiko , Nakano Takayoshi
Published: March 2017

Intact bone tissue exhibits a characteristic anisotropic microstructure derived from collagen fiber alignment and the related c-axis orientation of apatite crystals, which govern the mechanical properties of bone tissue. In contrast, tumor-invaded bone exhibits a disorganized, less-aligned microstructure that results in severely disrupted mechanical function. Despite its importance both in basic principle and in therapeutic applications, the classical understanding of bone metastasis is limited to alterations in bone mass regulated by metastatic cancer cells. In this study, we demonstrate a novel mechanism underlying the disruption of bone tissue anisotropy in metastasized bone. We observed that direct attack by cancer cells on osteoblasts induces the less-organized osteoblast arrangement. Importantly, the crystallographic anisotropy of bone tissue is quantitatively determined by the level of osteoblast arrangement. Osteoblast arrangement was significantly disrupted by physical contact with cancer cells such as osteolytic melanoma B16F10, breast cancer MDA-MB-231, and osteoblastic prostate cancer MDA-PCa-2b cells. The present findings demonstrate that the abnormal arrangement of osteoblasts induced by physical contact with cancer cells facilitates the disorganized microstructure of metastasized bone.
Consumer species richness and nutrients interact in determining producer diversity
Authors: Groendahl Sophie , Fink Patrick
Published: March 2017

While it is crucial to understand the factors that determine the biodiversity of primary producer communities, the relative importance of bottom-up and top-down control factors is still poorly understood. Using freshwater benthic algal communities in the laboratory as a model system, we find an unimodal relationship between nutrient availability and producer diversity, and that increasing number of consumer species increases producer diversity, but overall grazing decreases algal biodiversity. Interestingly, these two factors interact strongly in determining producer diversity, as an increase in nutrient supply diminishes the positive effect of consumer species richness on producer biodiversity. This novel and thus-far overlooked interaction of bottom-up and top-down control mechanisms of biodiversity may have a pronounced impact on ecosystem functioning and thus have repercussions for the fields of biodiversity conservation and restoration.
UV-light promoted C–H bond activation of benzene and fluorobenzenes by an iridium(i) pincer complex
Authors: Hauser Simone A. , Emerson-King Jack , Habershon Scott , Chaplin Adrian B.
Published: March 2017

UV irradiation of [Ir(2,6-(PtBu2CH2)2C6H3)(CO)] generates the transient and reactive 14 VE Ir(i) fragment {Ir(2,6-(PtBu2CH2)2C6H3)}, which subsequently undergoes C–H bond activation of benzene and fluorobenzenes.
Stereoselective binding of agonists to the β2-adrenergic receptor: insights into molecular details and thermodynamics from molecular dynamics simulations
Authors: Plazinska Anita , Plazinski Wojciech
Published: March 2017

Enhanced-sampling molecular dynamics simulations show the molecular details of stereospecific binding of agonists to the β2-adrenergic receptor.
Discrete wavelet assisted correlation optimised warping of chromatograms: optimizing the computational time for correcting the drifts in peak positions
Authors: Kumar Keshav
Published: March 2017

Discrete wavelet transform (DWT) assisted correlation optimised warping (COW) is shown to be a fast and efficient approach for correcting the retention time drifts of the chromatograms.
The oxidation kinetics of thin nickel films between 250 and 500 °C
Authors: Unutulmazsoy Y. , Merkle R. , Fischer D. , Mannhart J. , Maier J.
Published: March 2017

Diffusion controlled Ni oxidation is enhanced by fast grain boundary diffusion in growing nanocrystalline NiO films.
Surface point defects on bulk oxides: atomically-resolved scanning probe microscopy
Authors: Setvín Martin , Wagner Margareta , Schmid Michael , Parkinson Gareth S. , Diebold Ulrike
Published: March 2017

Metal oxides are abundant in nature and they are some of the most versatile materials for applications ranging from catalysis to novel electronics.
Inhibition of the MurA enzyme in Fusobacterium nucleatum by potential inhibitors identified through computational and in vitro approaches
Authors: Kumar Amit , Saranathan Rajagopalan , Prashanth K. , Tiwary Basant K. , Krishna Ramadas
Published: March 2017

Inhibition of MurA in open conformation by orientin and in closed conformation by quercetin-3-O-d-glucuronide with efficient inhibitory constant values.
Hierarchically templated beads with tailored pore structure for phosphopeptide capture and phosphoproteomics
Authors: Wierzbicka Celina , Torsetnes Silje B. , Jensen Ole N. , Shinde Sudhirkumar , Sellergren Börje
Published: March 2017

Phosphotyrosine selective beads prepared by polymer templating at two length scales results in improved capture of larger sized peptide fragments from tryptic protein digests.
The modulation effect of the convexity of silicon topological nanostructures on the growth of mesenchymal stem cells
Authors: Zou Yang , Feng Hongqing , Ouyang Han , Jin Yiming , Yu Min , Liu Zhuo , Li Zhou
Published: March 2017

The convexity of topological nanostructures, as analyzed by grey-level histogram and fast Fourier transformation, has important modulation effects on the size expansion and filopodia generation of mesenchymal stem cells.
Facile preparation of highly oriented poly(vinylidene fluoride) uniform films and their ferro- and piezoelectric properties
Authors: Xu Fan , Zhang Kaili , Zhou Ying , Qu Zhichao , Wang Haijun , Zhang Yamei , Zhou Haijun , Yan Chao
Published: March 2017

The shear-induced PVDF films present preferentially orientation with a high β-phase content and exhibit excellent ferro- and piezoelectric properties.
Flexible alternating current electroluminescent ammonia gas sensor
Authors: En-on Jaruwan , Tuantranont Adisorn , Kerdcharoen Teerakiat , Wongchoosuk Chatchawal
Published: March 2017

A new application of flexible alternating current electroluminescence, which combines display and gas sensor technologies, has been presented.
Hierarchical flower-like nickel phenylphosphonate microspheres and their calcined derivatives for supercapacitor electrodes
Authors: Zhang Fan , Bao Yuanyuan , Ma Shuangshuang , Liu Lu , Shi Xin
Published: March 2017

For the first time, hierarchical flower-like nickel phenylphosphonate microspheres were synthesized and applied as a high performance electrode material for pseudocapacitors.
Effect of different γ-subunit isoforms on the regulation of AMPK
Authors: Willows Robin , Navaratnam Naveenan , Lima Ana , Read Jon , Carling David
Published: March 2017

AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. AMPK activation results in a wide range of downstream responses, many of which are associated with improved metabolic outcome, making AMPK an attractive target for the treatment of metabolic diseases. AMPK is a heterotrimeric complex consisting of a catalytic subunit (α) and two regulatory subunits (β and γ). The γ-subunit harbours the nucleotide-binding sites and plays an important role in AMPK regulation in response to cellular energy levels. In mammals, there are three isoforms of the γ-subunit and these respond differently to regulation by nucleotides, but there is limited information regarding their role in activation by small molecules. Here, we determined the effect of different γ-isoforms on AMPK by a direct activator, 991. In cells, 991 led to a greater activation of γ2-containing AMPK complexes compared with either γ1 or γ3. This effect was dependent on the long N-terminal region of the γ2-isoform. We were able to rule out an effect of Ser108 phosphorylation, since mutation of Ser108 to alanine in the β2-isoform had no effect on activation of AMPK by 991 in either γ1- or γ2-complexes. The rate of dephosphorylation of Thr172 was slower for γ2- compared with γ1-complexes, both in the absence and presence of 991. Our studies show that activation of AMPK by 991 depends on the nature of the γ-isoform. This finding may have implications for the design of isoform-selective AMPK activators.
Retinoic acid combined with spermatogonial stem cell conditions facilitate the generation of mouse germ-like cells
Authors: Dong Guoyi , Shang Zhouchun , Liu Longqi , Liu Chuanyu , Ge Yuping , Wang Quanlei , Wu Liang , Chen Fang , Li Baolin , Liu Xin , Xu Xun , Yang Huanming , Du Yutao , Jiang Hui
Published: March 2017

Spermatogenic lineage has been directly generated in spermatogonial stem cell (SSC) conditions from human pluripotent stem cells (PSCs). However, it remains unknown whether mouse embryonic stem cells (ESCs) can directly differentiate into advanced male germ cell lineage in the same conditions. Here, we showed rather low efficiency of germ-like cell generation from mouse ESCs in SSC conditions. Interestingly, addition of retinoic acid (RA) into SSC conditions enabled efficient differentiation of mouse ESCs into germ-like cells, as shown by the activation of spermatogenesis-associated genes such as Mvh, Dazl, Prdm14, Stella, Scp1, Scp3, Stra8 and Rec8. In contrast, for cells cultured in control medium, the activation of the above genes barely occurred. In addition, RA with SSC conditions yielded colonies of Acrosin-expressing cells and the positive ratio reached a peak at day 6. Our work thus establishes a simple and cost-efficient approach for male germ like cell differentiation from mouse PSCs and may propose a useful strategy for studying spermatogenesis in vitro.
UAV rendezvous based on time‐varying vector fields
Authors: Jiang Wanyue , Wang Daobo , Wang Yin , Ali Zain Anwar
Published: March 2017

UAV rendezvous is a necessary precondition for formation flight. Fixed‐wing rendezvous is complex by nature because of its velocity constraints and uncertainties during flight. This Letter presents a rendezvous method for fixed‐wing UAVs, in which velocity tuning and online trajectory adjustment are combined. Time‐varying vector fields are designed to adjust the trajectories according to the estimated flight time, therefore the UAVs can reach the rendezvous position at the same time. This method can be applied in real time without complex communication topology. It is verified by the non‐linear mathematical model of a fixed‐wing UAV, and the simulated results confirm that it works effectively.
On coprimeness of two polynomials in the framework of conjugate product
Authors: Wu Ai‐Guo , Xu Yuan‐Rong
Published: March 2017

The right and left con‐Sylvester matrices for two polynomials are defined, and then the criteria for right and left coprimeness of two polynomials in the framework of conjugate product are given in terms of the determinant of the right and left con‐Sylvester matrices, respectively. The results in this study can be viewed as a generalisation of the well‐known Sylvester resultant criterion for coprimeness of two polynomials in the framework of ordinary product.
Controllability of dynamic‐algebraic Boolean networks based on a new normalisation approach
Authors: Li Bowen , Lou Jungang , Shi Wenping , Liu Yang , Alsaedi Ahmed , Alsaadi Fuad
Published: March 2017

In this study, the controllability of dynamic‐algebraic Boolean control networks is investigated based on a new normalisation approach. Some lower dimensional controllability matrices are defined, and new necessary and sufficient conditions for the controllability are presented as well. An example is given to illustrate the efficiency of the proposed results.
Probabilistic transmission network planning based on risk criteria
Authors: Klančnik Jurij , Pantoš Miloš
Published: March 2017

The proposed methodology introduces the risk concept, which takes into consideration the probability of the occurrence of different operating states, the probability of the outage of system elements, and the impact such outages would have on the electric power system (EPS). The impact on the EPS is assessed on the basis of a new indicator called impact on the grid, which takes into consideration all overloads caused by the outage of a particular element. The new methodology, based on a risk index, demonstrates the reliability of the EPS and provides background and arguments, useful for transmission system operators taking decisions regarding new investments on the transmission network (TN). The new methodology also contributes multi‐selection criteria for determining priorities among individual investments, based on investment costs and on maintaining a sufficient level of reliability.
Enhanced real‐time power balancing of an AC microgrid through transiently coupled droop control
Authors: Kallamadi Manjunath , Sarkar Vaskar
Published: March 2017

The objective of this study is to improve the real‐time operation of an AC microgrid for a network with high line R/X ratios. In specific, it is intended to achieve a stable microgrid operation along with accurate power sharing and minimal steady‐state frequency deviation following a load disturbance. A novel droop control (DC) methodology is proposed in this regard. For a network with high line R/X ratios, there exists coupling between active power and reactive power. In existing power transformation‐based approaches, the actual power sharing among different sources remains variable though both the system stability and the steady‐state frequency profile can be excellent. In the DC methodology proposed, the concept of power transformation is replaced with direct power versus voltage and reactive power versus frequency droop equations. However, the active power versus voltage and reactive power versus frequency cross‐couplings are taken into account only during the transient period. Therefore, the steady‐state power sharing takes place in the similar manner as in the case of the normal decoupled DC. All the droop parameters are independently tuned optimising the stability performance of the system. The robustness of the proposed methodology is verified through a detailed case study.
LFC for multi‐area interconnected power system concerning wind turbines based on DMPC
Authors: Ma Miaomiao , Liu Xiangjie , Zhang Chunyu
Published: March 2017

This study proposes a distributed model predictive control (DMPC) scheme for the load frequency control (LFC) problem of the multi‐area interconnected power system in the presence of wind turbines (WTs). The distributed model predictive controller is designed by formulating the LFC problem as disturbance attenuation problem in the presence of both external disturbances and constraints which represent load reference setpoint, generation rate constraint (GRC) and control input constraints of the WT, respectively. The frequency response model of three‐area power system concerning the aggregated WT model is introduced, in which the WT model is integrated into the interconnected power system to participate in LFC as a part of the power system. Simulation and analysis results for the three‐area interconnected power system with WTs indicate possible system performance improvements, while satisfying the physical hard constraints.
Sub‐optimal matching method for dual‐band class‐J power amplifier using real frequency technique
Authors: Dai Zhijiang , He Songbai , Pang Jingzhou , Peng Jun , Huang Chaoyi , You Fei
Published: March 2017

A passive network possessing an input impedance which is positive real in nature poses difficulties with regard to obtaining an optimal impedance for power amplifiers (PAs) with two uncorrelated frequencies. In this context, this study presents a sub‐optimal dual‐band matching method via real frequency technique. Theoretical analysis is presented for voltage waveform with four independent variables and boundary conditions are given for not lower than zero region. To increase the possibility of acquiring a matching network, a sub‐optimal but broad design space is defined according to acceptable performance. It is more practical to match dual‐band or broadband PAs because a single fundamental harmonic impedance point could be corresponding to a set of the second harmonics in the new design space, vice versa. Thus, the sub‐optimal solution space is bounded from region‐to‐region between the required fundamental and second harmonic impedances. An enhanced cost function based on driving point function that could better describe harmonic impedance mismatching degree is also proposed for harmonics control. Finally, a dual‐band PA is designed to demonstrate the general matching method. The peak efficiency is about 70% and saturated output power is 41 dBm in both bands.
System‐level SPICE model for predicting the effects of external incident EMI on a shielded communication system with an antenna
Authors: Li Xuelian , Du Zhengwei
Published: March 2017

A system‐level SPICE model is proposed to predict the effects of external incident electromagnetic interference (EMI) on a shielded communication system with an antenna in this study. First, hybrid techniques are incorporated to develop a frequency‐domain equivalent circuit model for the electromagnetic (EM) coupling of the system. The system is divided into an external subsystem and an internal subsystem. A receiving equivalent circuit model is established using the Lorentz reciprocity theorem for the EM coupling of the external subsystem. A transmission equivalent circuit model is established using the segmentation method for the signal transmission in the internal subsystem. Then, in order to handle the non‐linear or time‐varying circuit devices in the system, the macromodelling technique is employed to convert the frequency‐domain equivalent circuit model into a time‐domain system‐level SPICE model. Both numerical simulation and experimental verification are carried out to validate the proposed model. Based on the system‐level SPICE model, bit error rate is calculated to evaluate the performance of the communication system under external incident EMI in the ADS simulator.
Ultra‐wideband phased array for small satellite communications
Authors: Novak Markus H. , Miranda Félix A. , Volakis John L.
Published: March 2017

There is a continuing need for reducing size and weight of satellite systems, particularly in light of recent efforts to increase the functional role of small‐ and nano‐satellites (for instance SmallSats and CubeSats). To this end, a family of arrays is presented, demonstrating ultra‐wideband operation across the numerous satellite communications frequencies up to the Ku‐, Ka‐, and millimetre‐wave bands. The first design is demonstrated to operate from 3.5–18.5 GHz with VSWR < 2 at broadside, and validated through fabrication of an 8 × 8 prototype. Additional designs operating from 7–37 and 9–49 GHz, both with VSWR < 2.1 at broadside, are verified via simulations only. These designs are optimised for low cost, using printed circuit board fabrication and appropriate materials selection for space application. E‐ and H‐plane scanning patterns are provided. Finally, multi‐physics simulations of the array in high‐power transmit are conducted. Temperature trends and distribution are given, with the array showing favourable distribution of thermal energy at up to 2 W of RF input power per element, and a peak temperature only 40°C above ambient.
Depolarisation studies of single trees at 20 GHz
Authors: Caldeirinha Rafael F.S. , Al‐Nuaimi Miqdad O.
Published: March 2017

This study addresses the characterisation of the polarisation states of the re‐radiated signal from a natural tree performed in the vicinity around deep signal fades, at 20 GHz. The polarisation pattern method has been used to investigate the effects of depolarisation and to further characterise the changes in the polarisation state of the re‐radiated signal occurring as a result of the currents induced in the trunk, branches and leaves, which are significantly influenced by the complex permittivities of the various materials making up the tree. Results presented in this study will explain the signal behaviour observed in the various regions around the tree. The results also show that depolarisation, in addition to absorption and scatter, is an important factor formulating accurate models for propagation in vegetation.
Conceptual design and automated optimisation of a novel compact UWB MIMO slot antenna
Authors: Koziel Slawomir , Bekasiewicz Adrian , Cheng Qingsha S.
Published: March 2017

In this study, a concept and design optimisation procedure of a novel compact multiple‐input–multiple‐output (MIMO) slot antenna is presented. As the authors’ primary objective is to achieve a better utilisation of the available space, individual ultra‐wideband (UWB) antennas are constrained to a triangular shape and optimised for a reduced size. Subsequently, the MIMO structure is assembled using the previously designed radiators in orthogonal arrangement. Low computational cost of antenna geometry parameter adjustment is maintained by employing surrogate‐assisted optimisation involving variable‐fidelity electromagnetic simulation models. The footprint of the optimised MIMO design is only 630 mm2 and features very good isolation in the entire UWB frequency band. Numerical results are confirmed by experimental measurements of the fabricated prototype.
Reliable transmission of visible light communication data in lighting control networks
Authors: Choi Sang‐Il , Koh Seok‐Joo , Lim Sang‐Kyu , Kang Tae‐Gyu
Published: March 2017

Recently, the visible light communication (VLC) is considered as a future emerging technology in the telecommunication and lighting industry, as defined in the IEEE 802.15.7 standard. In the meantime, the ANSI E1.45 standard was made to provide VLC data transmissions from a VLC data server to a lighting device that is equipped with a VLC transmitter in lighting control networks. However, the ANSI E1.45 scheme cannot provide reliable transmissions of VLC data, and thus a lost data, if any, cannot be recovered. To overcome such limitation, timer‐based VLC data transmission schemes have been studied by applying the retransmission scheme of Internet. However, these schemes still have limitation that the lost VLC data cannot be recovered immediately. Hence, in this study, the authors propose new reliable transmission schemes for VLC data over lighting control networks. The proposed schemes are classified into the packet‐based (PRVS) and fragment‐based (FRVS) schemes. From performance analysis by simulation, the authors see that the FRVS gives the best transmission throughput among the four candidate schemes. In addition, it is shown that the proposed reliable transmission scheme can effectively perform the error recovery operation in the networks with packet losses, compared to the ANSI E1.45 scheme.
LCCT‐derived three‐level three‐phase inverters
Authors: Shults Tatiana , Husev Oleksandr , Blaabjerg Frede , Zakis Janis , Khandakji Kamal
Published: March 2017

Solutions for a family of the novel three‐level neutral‐point‐clamped (NPC) inductor‐capacitor‐capacitor‐transformer (LCCT)‐derived three‐phase inverters are described and compared. Component design guidelines and steady state analysis, current and voltage waveforms are given. The authors’ simulation results confirm the theoretical predictions. It was found that an asymmetrical three‐level NPC LCCT‐derived inverter with a single diode in the impedance source network is the most promising solution. Experimental results for an asymmetrical three‐level NPC LCCT‐derived inverter with a single input voltage source and continuous input current are presented. The main advantages and design requirements are discussed.
Improvement of the Barkhausen criterion and the implementation of an intelligent function generator
Authors: Lin Chia‐Wei , Chen Yen‐Ting , Chen Ying‐Chen , Chen Chung‐Cheng
Published: March 2017

Function generators are vital tools for many industrial applications. Sinusoidal oscillators are the essential units of function generators and investigating their performance is therefore necessary. The Barkhausen criterion is widely applied in designing sinusoidal oscillators because of its simplicity. The authors exploit a crucial necessary and sufficient oscillation criterion for Wien Bridge and Colpitts oscillators based on Simple Chen's Electric Unifying Approach. Their approach resolves the shortcoming of the traditional Barkhausen criterion, namely that it entails only a necessary condition. They propose a simple oscillation determining criterion that uses a stable sine‐wave oscillator with an adjustable oscillation frequency. The derived oscillation criterion establishes a precise condition for the existence of oscillatory behaviour and does not require the fixed value used in the traditional Barkhausen criterion. To demonstrate its applicability, the proposed approach for the Wien Bridge and Colpitts oscillators is applied to implement a function generator.
Exploring the behaviour of water nanodroplet on a coplanar electrowetting‐on‐dielectric: a molecular dynamics approach
Authors: Chan Hoi Kei , Mak Pui In , Siu Shirley W.I.
Published: March 2017

Molecular dynamics simulation has been used to investigate the behaviour of a water nanodroplet on a hydrophobic surface under an applied electric field. The model system mimics a typical electrowetting‐on‐dielectric experiment of an open‐plate coplanar electrodes system. Given the various strengths of the electrode‐induced field, variations in contact angle of the droplet, hydrogen bonding and diffusion coefficient of the water molecules are disclosed. Their main findings are: (i) nanodroplet displays asymmetric electrowetting in contact angle measurement; (ii) water molecules and the entire droplet are slightly positively biased; (iii) more water hydrogen bonds are maintained in the positive side, in both the first and the second hydration layer to the surface; and (iv) water diffusion is higher in parallel to the surface than the normal direction.
Stereoselective Cyclopropanation of (–)-Levoglucosenone Derivatives Using Sulfonium and Sulfoxonium Ylides
Authors: Ledingham Edward , Merritt Christopher , Sumby Christopher , Taylor Michelle , Greatrex Ben
Published: March 2017

The synthesis of tri- and tetrasubstituted cyclopropanes from 3-aryl-substituted levoglucosenones (LGO) has been developed. In contrast to the unstabilised ylide dimethylsulfonium methylide which gives epoxides from LGO via 1,2-addition, we have found that the soft nucleophile dimethylsulfoxonium methylide affords cyclopropanes in moderate yields from LGO and in excellent yields and stereoselectivity with 3-aryl LGO derivatives. The use of 1,1,3,3-tetramethylguanidine as base in DMSO to generate the ylide provided the best yields and shortest reaction times. Ester stabilised sulfonium ylides could also be used to generate tetrasubstituted cyclopropane derivatives. One of the products was converted into a cyclopropyl lactone via Baeyer–Villiger oxidation to demonstrate the utility of applying cyclopropanation chemistry to LGO.
Management of a Life Threatening Bleeding following Extraction of Deciduous Second Molar Related to a Capillary Haemangioma
Authors: Ghanem Amr Amin , el Hadidi Yasser Nabil
Published: March 2017

Various forms of vascular lesion affect the head and neck region. The head and neck vascular lesions are classified into neoplasms and malformations. Neoplasm presents either as hemangioma or lymphangioma; neoplasm usually presents in young age compared with vascular malformation. A 9-year-old female patient presented to the outpatient clinic referred from the department of pedodontics after extraction of a right mandibular second deciduous molar. Extraction was done by dental GP in outpatient clinic. Massive bleeding followed the extraction. Bleeding was controlled by electrocoagulation of bleeding site and systemic and local application of antifibrinolytic agent. An intravenous line was placed to provide fluid replacement. Injection of intravenous cyklokapron was given to stabilize the blood clot. Selective embolization was performed 24 hours prior to surgical resection of lesion and the lesion was removed under general anesthesia followed by peripheral ostectomy of bone to remove any feeders. Different protocols are used to control life-threatening bleeding. Primary local measures such as Gelfoam packing, Tranexamic or Aminocaproic topical application, Surgicel application, Electrocautery, Bone wax, Ligation of External Carotid or Common Carotid Artery, or Selective Embolization of feeder vessel may be used to control the bleeding. Interventional radiographic blockage of feeder vessel currently shows high success rate in the management of life-threatening bleeding compared with previous techniques.
Are There Changes in the Fatty Acid Profile of Breast Milk with Supplementation of Omega-3 Sources? A Systematic Review
Authors: Marano Daniele , Silva Leila Maria Lopes da , Guimarães Aline Carnevale Lia Dias , Moreira Maria Elisabeth Lopes , Amaral Yasmin Notarbartolo di Villarosa do
Published: March 2017

Purpose To evaluate the effect of supplementation with omega-3 sources on the fatty acid composition of human milk.

Methods The review consisted of the search for articles published in PubMed, Biblioteca Virtual de Saúde (Virtual Health Library[VHL]) and Web of Science databases using the following keywords: fatty acids, omega-3, human milk and supplementation; for this purpose, we have used the program of research to integrate the services for the maintenance of autonomy (PRISMA) checklist. The following selection criteria were used: articles in English, Portuguese, Spanish or Italian, published between 2000 and 2015, and about studies performed in humans. We found 710 articles that met the established criteria; however, only 22 of them were selected to be part of this study.

Results All studies found a positive relationship between the consumption of omega-3 sources and their concentration in human milk. The differences in the findings are due to the distinct methods used, such as the specific time of the omega-3 supplementation, the type of omega-3 source offered, as well as the sample size.

Conclusion Although the studies were different in several methodological aspects, it was possible to observe the importance of omega-3 supplementation during gestation and/or the puerperium.
A Giant Primary Retroperitoneal Serous Cystadenoma: Case Report and Review of Retroperitoneal Cysts
Authors: Mori Amit , Changela Kinesh , Alhankawi Dhuha , Itskovich Alexander , Butt Ahmar , Reddy Madhavi
Published: March 2017

Primary retroperitoneal serous cystadenomas (PRSCs) are rare cystic lesions whose pathogenesis is currently not well understood. Although the vast majority of tumors are benign, early recognition and resection is necessary to avoid malignant transformation, rupture, and secondary infection. Here we present the case of a 79-year-old woman who presented with confusion, visual hallucinations, and a history of fall. As part of the work-up for abdominal distension, computed tomography scan of the abdomen and pelvis was performed, which revealed a right-sided retroperitoneal cystic lesion measuring 26.6 × 16.7 cm in size. The lesion was resected laparoscopically, and the surgical specimen measured 28 × 17 cm. Histology revealed a serous cystadenoma. The postsurgical course was uneventful, and no radiological recurrence was noted on 3 months follow-up. Very few primary retroperitoneal cystic lesions have been reported in the literature. Most lesions are benign and predominantly occur in females. They may remain asymptomatic for long periods of time and are usually discovered when they reach very large in size. In rare cases, these lesions may have malignant potential. Diagnosis of PRSC should be considered in the differential diagnosis of all retroperitoneal cysts.
Developing a fast and tunable micro-mixer using induced vortices around a conductive flexible link
Authors: Azimi Shahriar , Nazari Mohsen , Daghighi Yasaman
Published: March 2017

This paper presents a numerical study of a micro-mixer based on the continuous deformation of a conducting flexible link. The induced vortices around the link enhance the mixing process. This micro-mixer consists of one straight microchannel and one conductive flexible link. One end of the link is fixed on the upper wall of the channel and the other end can move freely due to the fluid-solid interactions. Since this link is conductive, vortices form around the link (once the electric field is applied). Applying a time-varying DC electric field causes variation in the applied forces to the link; thus, the link will swipe the channel and acts as a micro-stirrer to enhance mixing results. The presented results show that there is a direct relationship between mixing efficiency and the length of the link, as well as the amplitude of time-varying DC electric field. The effects of Young’s modulus, the average of applied electric field, and link position are also studied. Link with lower Young’s modulus swipes larger area inside the channel and enhances the mixing efficiency. By increasing the length of the conductive link, large vortices will be induced around it and mixing efficiency enhances. Our numerical results show that average mixing efficiency of link with a length of L = 0.625 W = 156.25 μm is about 90%. The proposed micro-mixer is simple to be fabricated and mixes the fluid streams in a short period of time with high efficiency. Such micro-mixers can be used in various microfluidics, biomedical, or chemical applications.
Dynamic interference of two anti-phase flapping foils in side-by-side arrangement in an incompressible flow
Authors: Bao Y. , Zhou D. , Tao J. J. , Peng Z. , Zhu H. B. , Sun Z. L. , Tong H. L.
Published: March 2017

A two-dimensional computational hydrodynamic model is developed to investigate the propulsive performance of a flapping foil system in viscous incompressible flows, which consists of two anti-phase flapping foils in side-by-side arrangement. In the simulations, the gap between the two foils is varied from 1.0 to 4.0 times of the diameter of the semi-circular leading edge; the amplitude-based Strouhal number is changed from 0.06 to 0.55. The simulations therefore cover the flow regimes from negligible to strong interference in the wake flow. The generations of drag and thrust are investigated as well. The numerical results reveal that the counter-phase flapping motion significantly changes the hydrodynamic force generation and associated propulsive wake. Furthermore, the wake interference becomes important for the case with a smaller foil-foil gap and induces the inverted Bénard von Kármán vortex streets. The results show that the hydrodynamic performance of two anti-phase flapping foils can be significantly different from an isolated pitching foil. Findings of this study are expected to provide new insight for developing hydrodynamic propulsive systems by improving the performance based on the foil-foil interaction.
Valence shell threshold photoelectron spectroscopy of the CHxCN (x = 0-2) and CNC radicals
Authors: Garcia Gustavo A. , Krüger Julia , Gans Bérenger , Falvo Cyril , Coudert Laurent H. , Loison Jean-Christophe
Published: March 2017

We present the photoelectron spectroscopy of four radical species, CHxCN (x = 0-2) and CNC, formed in a microwave discharge flow-tube reactor by consecutive H abstractions from CH3CN (CHxCN + F → CHx−1CN + HF (x = 1-3)). The spectra were obtained combining tunable vacuum ultraviolet synchrotron radiation with double imaging electron/ion coincidence techniques, which yielded mass-selected threshold photoelectron spectra. The results obtained for H2CCN complement existing ones while for the other radicals the data represent the first observation of their (single-photon) ionizing transitions. In the case of H2CCN, Franck-Condon calculations have been performed in order to assign the vibrational structure of the X+ 1A1←X 2B1 ionizing transition. A similar treatment for the HCCN, CCN, and CNC radicals appeared to be more complicated mainly because a Renner-Teller effect strongly affects the vibrational levels of the ground electronic state of the HCCN+, CCN, and CNC species. Nevertheless, the first adiabatic ionization energies of these radicals are reported and compared to our ab initio calculated values, leading to new values for enthalpies of formation (ΔfH2980(HCCN+(X2A′))=1517±12kJmol−1,ΔfH2980(CCN(X2Π))=682±13kJmol−1, and ΔfH2980(CNC(X2Πg))=676±12kJmol−1), which are of fundamental importance for astrochemistry.
Numerical modeling of a glow discharge through a supersonic bow shock in air
Authors: Rassou S. , Packan D. , Elias P.-Q. , Tholin F. , Chemartin L. , Labaune J.
Published: March 2017

The interaction between a glow discharge and the bow shock of a Mach 3 air flow around a truncated conical model with a central spike is modeled, and comparison is made with prior experimental results. The KRONOS workflow for plasma modeling in flow fields, which has recently been developed at ONERA, was used for the modeling. Based on the quasi-neutral approximation, it couples hypersonic and reactive flow fields with electron chemistry, including the effect of non-Maxwellian electron energy distribution function. The model used for the discharge involves 12 species and 82 reactions, including ionization, electronic and vibrational excitation, and attachment. The simulations reproduce the main features of the discharge observed experimentally well, in particular, the very recognizable topology of the discharge. It was found from the simulations that behind the bow shock, in the afterglow, the negative ion flow ensures the electrical conduction and the establishment of the glow discharge. The influence of kinetic rates on the voltage-current characteristics is discussed.
Bright synchrotron radiation from nano-forest targets
Authors: Lécz Zs. , Andreev A.
Published: March 2017

This paper proposes an intense x-ray source based on the interactions of intense laser pulses with nanowire targets. The presented electron dynamics and energy scalings have been studied by three dimensional particle-in-cell simulations. The resonance of the electronic betatron oscillations with the incident laser field results in extremely high energy electrons. The scaling of radiation intensity is predicted to be ∼IL5/2, where IL is the laser intensity, using optimal parameters. In this case, the number of photons emitted, via synchrotron radiation, with energies above the keV level with 0.1 rad angular spread is greater than 108/fs for intensities IL>1020 W/cm2. This scaling law suggests that the photon flux production using nanowires of suitable lengths is much greater than in a underdense plasma.
Strongly temperature dependent resistance of meander-patterned graphene
Authors: Vasileva G. Yu. , Smirnov D. , Vasilyev Yu. B. , Nestoklon M. O. , Averkiev N. S. , Novikov S. , Kaya I. I. , Haug R. J.
Published: March 2017

We have studied the electronic properties of epitaxial graphene devices patterned in a meander shape with the length up to a few centimeters and the width of few tens of microns. These samples show a pronounced dependence of the resistance on temperature. Accurate comparison with the theory shows that this temperature dependence originates from the weak localization effect observed over a broad temperature range from 1.5 K up to 77 K. The comparison allows us to estimate the characteristic times related to quantum interference. In addition, a large resistance enhancement with temperature is observed at the quantum Hall regime near the filling factor of 2. Record high resistance and its strong temperature dependence are favorable for the construction of bolometric photodetectors.
Nanometer-scale mapping of defect-induced luminescence centers in cadmium sulfide nanowires
Authors: Cretu Ovidiu , Zhang Chao , Golberg Dmitri
Published: March 2017

The luminescence centers in cadmium sulfide (CdS) nanowires are mapped through cathodoluminescence experiments inside a high resolution transmission electron microscope. This is made possible by positioning an optical fiber within a few micrometers of the area of interest and scanning the focused electron beam while simultaneously collecting the generated photons. The results reveal the distribution of luminescence centers in this material with nanometer-precision. Furthermore, these centers are associated with various intrinsic defects in CdS, which allows mapping these defects even when their concentration is far below the level detectable by other traditional techniques.