bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional germline variants as potential co-oncogenes
Authors: Agarwal Divyansh , Nowak Christoph , Zhang Nancy R. , Pusztai Lajos , Hatzis Christos
Published: November 2017

Germline variants that affect the expression or function of proteins contribute to phenotypic variation in humans and likely determine individual characteristics and susceptibility to diseases including cancer. A number of high penetrance germline variants that increase cancer risk have been identified and studied, but germline functional polymorphisms are not typically considered in the context of cancer biology, where the focus is primarily on somatic mutations. Yet, there is evidence from familial cancers indicating that specific cancer subtypes tend to arise in carriers of high-risk germline variants (e.g., triple negative breast cancers in mutated BRCA carriers), which suggests that pre-existing germline variants may determine which complementary somatic driver mutations are needed to drive tumorigenesis. Recent genome sequencing studies of large breast cancer cohorts reported only a handful of highly recurrent driver mutations, suggesting that different oncogenic events drive individual cancers. Here, we propose that germline polymorphisms can function as oncogenic modifiers, or co-oncogenes, and these determine what complementary subsequent somatic events are required for full malignant transformation. Therefore, we propose that germline aberrations should be considered together with somatic mutations to determine what genes drive cancer and how they may be targeted.
Advances in malaria vaccine development: report from the 2017 malaria vaccine symposium
Authors: Coelho Camila Henriques , Doritchamou Justin Yai Alamou , Zaidi Irfan , Duffy Patrick E.
Published: November 2017

The Malaria Vaccine Symposium occurred at Johns Hopkins University in Baltimore, MD, USA on April 25th, 2017, coinciding with World Malaria Day and the WHO announcement that the RTS,S malaria vaccine would begin pilot implementation programs in Ghana, Kenya, and Malawi in 2018. Scientists from several disciplines reported progress on an array of malaria vaccine concepts and product candidates, including pre-erythrocytic vaccines that prevent infection, blood-stage vaccines that limit infection and disease, and transmission-blocking vaccines that interrupt the spread of infection. Other speakers highlighted the immunological and genetic considerations that must be addressed by vaccinologists to yield the most efficacious vaccines. Here, we highlight the advances in malaria vaccinology that were reported at the symposium.
Taxonomy and Identification of the Genus Scolopendra in China Using Integrated Methods of External Morphology and Molecular Phylogenetics
Authors: Kang Sihe , Liu Yimei , Zeng Xiaoxuan , Deng Haiying , Luo Ying , Chen Keli , Chen Shilin
Published: November 2017

The centipede Scolopendra has important medicinal value and high toxicity, making it to be an interesting subject for evolutionary studies. However, species identification in China is difficult because of limited resource exploration and lack of recent taxonomic revision. To improve the identification and taxonomy of the genus Scolopendra in China, an in-depth investigation was conducted, and an integrated method that combined morphological characteristics with molecular data was applied. The identification key was revised to show the main difference among species. Our results indicated that morphologically-delimited species were consistent with the molecular analysis inferred from the COI sequences with genetic distances and phylogenetic trees. Additional morphometrics of four characteristics provided criteria for shape variation. These results suggested that the members of the genus Scolopendra in China could be delineated as 14 separate species. A new species from Lufeng county, Yunnan province, was proposed according to its characteristics, which was named as S. lufengia sp. nov. Our results comprehensively ascertained the taxonomic status of Scolopendra species in China, explored their phylogenetic relationships, showed a high success in the identification of medicinal centipedes.
Transcriptome and metabolite analyses reveal the complex metabolic genes involved in volatile terpenoid biosynthesis in garden sage (Salvia officinalis)
Authors: Ali Mohammed , Li Penghui , She Guangbiao , Chen Daofu , Wan Xiaochun , Zhao Jian
Published: November 2017

A large number of terpenoid compounds have been extracted from different tissues of S. officinalis. However, the molecular genetic basis of terpene biosynthesis pathways is virtually unknown. In this study, approximately 6.6 Gb of raw data were generated from the transcriptome of S. officinalis leaves using Illumina HiSeq 2000 sequencing. After filtering and removing the adapter sequences from the raw data, the number of reads reached 21 million, comprising 98 million of high-quality nucleotide bases. 48,671 unigenes were assembled de novo and annotated for establishing a valid database for studying terpenoid biosynthesis. We identified 135 unigenes that are putatively involved in terpenoid metabolism, including 70 mevalonate and methyl-erythritol phosphate pathways, terpenoid backbone biosynthesis genes, and 65 terpene synthase genes. Moreover, five terpene synthase genes were studied for their functions in terpenoid biosynthesis by using transgenic tobacco; most transgenic tobacco plants expressing these terpene synthetic genes produced increased amounts of terpenoids compared with wild-type control. The combined data analyses from the transcriptome and metabolome provide new insights into our understanding of the complex metabolic genes in terpenoid-rich sage, and our study paves the way for the future metabolic engineering of the biosynthesis of useful terpene compounds in S. officinalis.
Band gap engineering of In(Ga)N/GaN short period superlattices
Authors: Gorczyca I. , Suski T. , Strak P. , Staszczak G. , Christensen N. E.
Published: November 2017

Discussion of band gap behavior based on first principles calculations of the electronic band structures for several InN/GaN superlattices (SLs) (free-standing and pseudomorphic) grown along different directions (polar and nonpolar) is presented. Taking into account the dependence on internal strain and lattice geometry mainly two factors influence the dependence of the band gap, E
g
on the layer thickness: the internal electric field and the hyb wells) is more important. We also consider mIn ridization of well and barrier wave functions. We illustrate their influence on the band gap engineering by calculating the strength of built-in electric field and the oscillator strength. It appears that there are two interesting ranges of layer thicknesses. In one the influence of the electric field on the gaps is dominant (wider wells), whereas in the other the wave function hybridization (narrow wells) is more important. We also consider mIn
0.33
Ga
0.67
N/nGaN SLs, which seem to be easier to fabricate than high In content quantum wells. The calculated band gaps are compared with recent experimental data. It is shown that for In(Ga)N/GaN superlattices it is possible to exceed by far the range of band gap values, which can be realized in ternary InGaN alloys.
Micromechanical Resonator Driven by Radiation Pressure Force
Authors: Boales Joseph A. , Mateen Farrukh , Mohanty Pritiraj
Published: November 2017

Radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. The associated force – fundamentally, a quantum mechanical aspect of light – is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics. In atomic and molecular optics, radiation pressure can be used to trap or cool atoms and ions. Use of radiation pressure on larger objects such as micromechanical resonators has been so far limited to its coupling to an acoustic mode, sideband cooling, or levitation of microscopic objects. In this Letter, we demonstrate direct actuation of a radio-frequency micromechanical plate-type resonator by the radiation pressure force generated by a standard laser diode at room temperature. Using two independent methods, the magnitude of the resonator’s response to forcing by radiation pressure is found to be proportional to the intensity of the incident light.
Symmetry breaking, Josephson oscillation and self-trapping in a self-bound three-dimensional quantum ball
Authors: Adhikari S. K.
Published: November 2017

We study spontaneous symmetry breaking (SSB), Josephson oscillation, and self-trapping in a stable, mobile, three-dimensional matter-wave spherical quantum ball self-bound by attractive two-body and repulsive three-body interactions. The SSB is realized by a parity-symmetric (a) one-dimensional (1D) double-well potential or (b) a 1D Gaussian potential, both along the z axis and no potential along the x and y axes. In the presence of each of these potentials, the symmetric ground state dynamically evolves into a doubly-degenerate SSB ground state. If the SSB ground state in the double well, predominantly located in the first well (z > 0), is given a small displacement, the quantum ball oscillates with a self-trapping in the first well. For a medium displacement one encounters an asymmetric Josephson oscillation. The asymmetric oscillation is a consequence of SSB. The study is performed by a variational and a numerical solution of a non-linear mean-field model with 1D parity-symmetric perturbations.
Long-Read Sequencing of Human Cytomegalovirus Transcriptome Reveals RNA Isoforms Carrying Distinct Coding Potentials
Authors: Balázs Zsolt , Tombácz Dóra , Szűcs Attila , Csabai Zsolt , Megyeri Klára , Petrov Alexey N. , Snyder Michael , Boldogkői Zsolt
Published: November 2017

The human cytomegalovirus (HCMV) is a ubiquitous, human pathogenic herpesvirus. The complete viral genome is transcriptionally active during infection; however, a large part of its transcriptome has yet to be annotated. In this work, we applied the amplified isoform sequencing technique from Pacific Biosciences to characterize the lytic transcriptome of HCMV strain Towne varS. We developed a pipeline for transcript annotation using long-read sequencing data. We identified 248 transcriptional start sites, 116 transcriptional termination sites and 80 splicing events. Using this information, we have annotated 291 previously undescribed or only partially annotated transcript isoforms, including eight novel antisense transcripts and their isoforms, as well as a novel transcript (RS2) in the short repeat region, partially antisense to RS1. Similarly to other organisms, we discovered a high transcriptional diversity in HCMV, with many transcripts only slightly differing from one another. Comparing our transcriptome profiling results to an earlier ribosome footprint analysis, we have concluded that the majority of the transcripts contain multiple translationally active ORFs, and also that most isoforms contain unique combinations of ORFs. Based on these results, we propose that one important function of this transcriptional diversity may be to provide a regulatory mechanism at the level of translation.
Structural analyses of adenylate kinases from Antarctic and tropical fishes for understanding cold adaptation of enzymes
Authors: Moon Sojin , Kim Junhyung , Bae Euiyoung
Published: November 2017

Psychrophiles are extremophilic organisms capable of thriving in cold environments. Proteins from these cold-adapted organisms can remain physiologically functional at low temperatures, but are structurally unstable even at moderate temperatures. Here, we report the crystal structure of adenylate kinase (AK) from the Antarctic fish Notothenia coriiceps, and identify the structural basis of cold adaptation by comparison with homologues from tropical fishes including Danio rerio. The structure of N. coriiceps AK (AKNc) revealed suboptimal hydrophobic packing around three Val residues in its central CORE domain, which are replaced with Ile residues in D. rerio AK (AKDr). The Val-to-Ile mutations that improve hydrophobic CORE packing in AKNc increased stability at high temperatures but decreased activity at low temperatures, suggesting that the suboptimal hydrophobic CORE packing is important for cold adaptation. Such linkage between stability and activity was also observed in AKDr. Ile-to-Val mutations that destabilized the tropical AK resulted in increased activity at low temperatures. Our results provide the structural basis of cold adaptation of a psychrophilic enzyme from a multicellular, eukaryotic organism, and highlight the similarities and differences in the structural adjustment of vertebrate and bacterial psychrophilic AKs during cold adaptation.
Development and validation of scFv-conjugated affinity silk protein for specific detection of carcinoembryonic antigen
Authors: Sato Mitsuru , Kitani Hiroshi , Kojima Katsura
Published: November 2017

The production costs for monoclonal antibodies (MAbs) utilized in medical diagnostic kits are inevitably high because the MAbs are mostly obtained from hybridoma cell culture. Here, we report the development and validation of a novel affinity silk protein produced by transgenic silkworm technology as a possible alternative diagnostic tool for cancers. We generated a transgenic silkworm expressing a cDNA construct containing fibroin L-chain fused to a single-chain variable fragment (scFv) derived from a MAb against carcinoembryonic antigen (CEA). The transgenic cocoons were dissolved in aqueous lithium bromide solution, applied to 96-well plates, and analysed by enzyme-linked immunosorbent assay. The scFv-conjugated affinity silk protein specifically recognized CEA as well as the parental MAb. The binding activity was retained after several months of storage in coated plates or concentrated solution. Thus, the scFv-conjugated affinity silk protein provides a potentially useful alternative to conventional MAbs in medical diagnostic kits.
Creation and Annihilation of Skyrmions in the Frustrated Magnets with Competing Exchange Interactions
Authors: Hu Yong , Chi Xiaodan , Li Xuesi , Liu Yan , Du An
Published: November 2017

In triangular-lattice magnets, the coexistence of third-neighbor antiferromagnetic and nearest-neighbor ferromagnetic exchange interactions can induce rich magnetic phases including noncoplanar skyrmion crystals. Based on Monte Carlo simulation, we studied the dependence of magnetic phase transition on exchange interaction strength. Under the consideration of uniaxial anisotropy and magnetic field both perpendicular to the film plane, a large antiferromagnetic exchange interaction induces a high frustration. When the value of antiferromagnetic exchange interaction is one and a half times larger than the ferromagnetic one, a magnetic phase composed of canting spin stripes, never observed in the chiral magnets, forms. Interestingly, different canting spin stripes along three 120 degree propagation directions may coexist randomly in a magnetic phase, attesting that the canting spin stripes are three-fold degenerate states akin to helices and the multiple state of canting spin stripes is a circular configuration with zero skyrmion charge number. Moreover, skyrmions and antiskyrmions can be observed simultaneously in the configuration at the low temperature nearly close to 0 K, and their configuration and diameter properties are discussed. Finally, the mechanisms of skyrmion creation and annihilation are properly interpreted by comparing exchange and Zeeman energy terms.
Transcriptome responses of Streptococcus mutans to peroxide stress: identification of novel antioxidant pathways regulated by Spx
Authors: Kajfasz Jessica K. , Ganguly Tridib , Hardin Emily L. , Abranches Jacqueline , Lemos José A.
Published: November 2017

The oxidative stress regulator Spx is ubiquitously found among Gram-positive bacteria. Previously, we reported identification of two Spx proteins in Streptococcus mutans – SpxA1 was the primary activator of oxidative stress genes whereas SpxA2 served a backup role. Here, we used RNA sequencing to uncover the scope of the H2O2 (peroxide)-stress regulon and to further explore the significance of Spx regulation in S. mutans. The transcriptome data confirmed the relationship between Spx and genes typically associated with oxidative stress, but also identified novel genes and metabolic pathways controlled by Spx during peroxide stress. While individual inactivation of newly identified peroxide stress genes had modest or no obvious consequences to bacterial survival, a phenotype enhancement screen using the ∆spxA1 strain as background for creation of double mutants revealed that four of the five genes inactivated were required for stress survival. Physiological and biochemical assays validated, at least in part, the transcriptome data indicating that SpxA1 coordinates transcriptional changes during peroxide stress that modify global metabolism and facilitate production of antioxidants. Collectively, our findings unraveled the scope of the peroxide stress regulon and expand the repertoire of oxidative stress genes in S. mutans, shedding new light on the role of Spx regulation.
Nanotopography-based strategy for the precise manipulation of osteoimmunomodulation in bone regeneration
Authors: Chen Zetao , Bachhuka Akash , Wei Fei , Wang Xiaoshuang , Liu Guanqi , Vasilev Krasimir , Xiao Yin
Published: November 2017

A nanotopography-based strategy to precisely manipulate the osteoimmune environment for bone regeneration.
Synthesis of 4-substituted pyrazole-3,5-diamines via Suzuki–Miyaura coupling and iron-catalyzed reduction
Authors: Tomanová Monika , Jedinák Lukáš , Košař Jan , Kvapil Lubomír , Hradil Pavel , Cankař Petr
Published: November 2017

A general and efficient synthesis of 4-substituted-1H-pyrazole-3,5-diamines was developed to access derivatives with an aryl, heteroaryl, or styryl group, which are otherwise relatively difficult to prepare.
Interacting layered hydroxide nanosheets with KF leading to Y/Eu hydroxyfluoride, oxyfluoride, and complex fluoride nanocrystals and investigation of photoluminescence
Authors: Li Jing , Wang Xuejiao , Zhu Qi , Kim Byung-Nam , Sun Xudong , Li Ji-Guang
Published: November 2017

Reacting nanosheets (∼4 nm thick) of RE2(OH)5NO3·nH2O layered hydroxyl nitrate with KF has led to various types of fluorides for photoluminescence.
Catalyst characterization in the presence of solvent: development of liquid phase structure–activity relationships
Authors: Gould Nicholas S. , Xu Bingjun
Published: November 2017

Due to the low volatility and highly oxygenated nature of biomass derived feedstocks, biomass upgrade reactions are frequently conducted in the presence of solvent to improve substrate mass transfer to the catalyst surface.
Distributed secondary and tertiary controls for I–V droop‐controlled‐paralleled DC–DC converters
Authors: Wang Haojie , Han Minxiao , Guerrero Josep M. , Vasquez Juan C. , Teshager Bitew G.
Published: November 2017

A hierarchical distributed control method for I–V droop‐controlled‐paralleled DC–DC converters in DC microgrid is proposed. The control structure includes primary, secondary, and tertiary levels. The secondary control level is used to remove the DC voltage deviation and improve the current sharing accuracy. An improved dynamic consensus algorithm is used in the secondary control to calculate the average values of bus voltage and voltage restoration in distributed control. In the tertiary control level, as the main contribution in this study, the system conversion efficiency is enhanced by using the average restoration value obtained in the secondary control level, instead of using the total load current which needs more communication traffic. When the converters are connected to batteries, the method for the state of charge (SoC) management is proposed so that the SoC balance can be guaranteed. The effectiveness of the proposed method is verified by detailed experimental tests based on four 0.7 kW DC–DC converters.
Using smart meters to estimate low‐voltage losses
Authors: Poursharif Goudarz , Brint Andrew , Black Mary , Marshall Mark
Published: November 2017

Losses on low‐voltage networks are often substantial. For example, in the UK they have been estimated as being 4% of the energy supplied by low‐voltage networks. However, the breakdown of the losses to individual conductors and their split over time are poorly understood as generally only the peak demands and average loads over several months have been recorded. The introduction of domestic smart meters has the potential to change this. How domestic smart meter readings can be used to estimate the actual losses is analysed. In particular, the accuracy of using 30 min readings compared with 1 min readings, and how this accuracy could be improved, were investigated. This was achieved by assigning the data recorded by 100 smart meters with a time resolution of 1 min to three test networks. Smart meter data from three sources were used in the investigation. It was found that 30 min resolution data underestimated the losses by between 9 and 24%. By fitting an appropriate model to the data, it was possible to reduce the inaccuracy by ∼50%. Having a smart meter time resolution of 10 min rather than 30 gave little improvement to the accuracy.
Robust feedback‐linearisation control of a boost converter feeding a grid‐tied inverter for PV applications
Authors: Errouissi Rachid , Al‐Durra Ahmed , Muyeen S.M. , El Aroudi Abdelali
Published: November 2017

In this study, the feedback‐linearisation (FBL) technique is employed to design a dc–dc boost voltage regulator feeding a grid‐tied inverter for photovoltaic (PV) systems. The key feature of the proposed approach is that only a voltage control loop is used to generate the driving signal for the converter and no current control loop is required. Thereby, unlike the cascaded structure, the bandwidth of the voltage control loop can be specified only by the switching frequency as there is no need for an intermediate inner‐loop. The major concern of this control scheme is its limited ability to eliminate completely the steady‐state error under model uncertainty and unknown disturbance such as the PV current, which is considered as an unmatched disturbance. For this purpose, the unknown perturbation is estimated by a disturbance observer and compensated in the control law to drive the steady‐state error to zero. With a fast disturbance estimation, the composite controller is able to retain the nominal transient performance specified with the FBL. The effectiveness of the proposed approach was verified by both simulation and experimental results, and a remarkable agreement was obtained while exhibiting excellent performances.
Evaluation of an advanced model reference sliding mode control method for cardiac assist device using a numerical model
Authors: Bakouri Mohsen
Published: November 2017

In this study, the physiological control algorithm using sliding mode control method is implemented to track the reference input signal. The controller is developed using feed‐forward part, reference model, and steady‐state flow estimator. The proposed control method is evaluated using a dynamic heart‐pump interaction model incorporating descriptions of the cardiovascular system – rotary blood pump. The immediate response of the controller to preload as well as afterload was studied. Stability and feasibility of the control system were demonstrated through the tests. The results showed that the present controller, which allows the left ventricular to automatically adjust to the right ventricular output, reduces the risk of suction.
Two‐phase integrated optimisation strategy for network restoration with photovoltaic generation
Authors: Jiang Ziqing , Xiao Fei , Ai Qian , He Qilin , Sun Qiu
Published: November 2017

Compared with conventional generation techniques, photovoltaic (PV) generation, which is widely spread and easily connected to the grid, has an excellent ability of self‐starting, making it a promising alternative of black‐start (BS) sources. Considering the difference between PV units and conventional BS sources, a two‐phase network restoration strategy is proposed. In phase 1, a certain thermal power unit is selected using the Floyd algorithm and then started by PV units within the blackout network, with the objective to maximise the launching possibility. In phase 2, the unit started in phase 1 is used as the main power source, while PV units as the auxiliary source, to finish the whole restoration procedure. The backtracking algorithm and the Dijkstra algorithm are applied with the objective to maximise the power restored and minimise the time needed during the restoration. Taking the objectives of the two phases into consideration, an integrated optimisation method is proposed, which could guarantee the restoration efficiency and fix the disadvantages of PV system such as low inertia and relatively poorer starting ability. The case study of IEEE 39‐bus system proves the practicability and the effectiveness of the method proposed.
Optimal reconfiguration of the active distribution network with distributed generation and electric vehicle
Authors: Zhang Dongfang , Zhang Tao , Xu Xueqin , Zhou Yuanhua , Zhang Xiaolin
Published: November 2017

It is a challenge to the stable operation of the active distribution network (ADN) with the distributed generation (DG) and electric vehicle (EV), and the reconfiguration is an important method to improve the stability of the system. The multi‐objective reconfiguration model is established under the battery‐swapping mode, the network loss and the voltage deviation index (VDI) are set up as the optimisation functions, and the number of switching operations is considered as the constraint. The global optimal position is updated through the niche technique; the optimal compromise solution is chose from the Pareto solutions using the fuzzy satisfaction evaluation decision method. Finally, the effects of different scenarios on the target value and the voltage of each node are compared and analysed from the simulation results in IEEE69 nodes system. The results show that the proposed method can effectively improve the stability of the system.
Coordinated control strategy of hybrid energy storage to improve accommodating ability of PV
Authors: Zhang Delong , Guo Jianbo , Li Jianlin
Published: November 2017

The energy storage system of PV power plant can improve the accommodating ability of photovoltaic (PV) generation. The coordinated control of hybrid energy storage system (HESS) becomes one of the urgent problems to be solved. This study proposes a coordinated control strategy of HESS with complementary features to improve the accommodating ability of PV. In the 1 min time scale, a time window selection method is proposed to control the super conductor to smooth the short‐term fluctuation of the PV. In the 1 h time scale, the lithium‐ion battery output model maximising the system economic benefit is established, and the particle swarm optimisation algorithm is used to solve the model. Based on the result of 1 h time scale, the objective function of reducing the fluctuation of electric power consumption is established and solved on the 15 min time scale. The effectiveness of the proposed control strategy is verified by simulation. The coordinated operation of HESS improves the utilisation rate of the PV power generation.
Identification of vulnerable lines in large power grid based on FP‐growth algorithm
Authors: Jiang Shengbo , Pan Xueli , Xiao Yi , Zhou Qiangming , Li Miao , Yang Jun
Published: November 2017

The complexity of the power grid structure and its operating mode has greatly enhanced, increasing the probability of the large‐scale blackout. Identifying the vulnerable lines in the process of cascading failure plays an important role in adopting effective suppression strategy to ensure the safety and stability of the power grid. An frequent pattern (FP)‐growth algorithm‐based method of identifying vulnerable lines in large power grid is proposed in this study. Based on the model of operational reliability, the cascading failures are simulated and chains of failure are generated. This study mines the sets of failure chain to discover the frequent items in the sets and to identify the vulnerable lines in the development process of cascading failures. Also, this study analyses the risk of vulnerable lines and its impact on cascading failure. Simulation results of IEEE118‐Bus benchmark show that the proposed method can identify dangerous lines in the development process of chain fault effectively, which is important for suppressing the cascading failures and reducing the power failure probability.
Control for offshore wind power integration based on modular multilevel converter
Authors: Lv Cheng , Tai Nengling
Published: November 2017

The voltage source converter‐based high‐voltage direct current (VSC‐HVDC) is introduced and used in the integration. Nowadays, the application of the modular multilevel converter (MMC) is attracting more and more attention in the large‐scale offshore wind power integration. With the rapid development of wind power and other distribution generators, VSC‐HVDC can no longer meet the requirement of large capacity and good economy, making MMC‐HVDC a tendency of the large‐scale offshore wind power integration. The basic research of MMC has been concluded in this study. It is necessary to investigate the control for offshore wind power integration based on MMC. Besides, converters connected to wind farms take the constant ac voltage control, in which the voltage reference is constant. This study explains the basic control theory of MMC‐HVDC. Then an adaptive control for offshore wind power integration is investigated in detail. Finally, a three‐terminal MMC‐HVDC system is established in PSCAD/EMTDC for simulation and verification.
Bifurcation analysis of the islanded micro‐grid with constant power loads
Authors: Hu Yifan , Peng Yelun , Shuai Zhikang
Published: November 2017

Most of the distributed energy resources (DERs) are connected to the micro‐grid through the power electronic inverter. Due to the limited inertial and capacity of the inverter‐based DERs, the micro‐grid in islanded mode is susceptible to the non‐linear instability such as oscillation. In this study, the authors analyse the non‐linear behaviour of an islanded micro‐grid with constant power load by the bifurcation theory. At first, the proposed micro‐grid is developed on the dq reference frame. Then, the numerical bifurcation technique is used to detect the bifurcation point when parameters change. Considering the current limitation of the DERs, the non‐linear instability of the micro‐grid caused by the current saturation is also investigated. Simulation validates the detected bifurcation phenomena of the proposed micro‐grid.
Dispatching approach for active distribution network considering PV generation reliability and load predicting interval
Authors: Ying Yiqiang , Wu Yingjun , Su Yiqiang , Fu Rong , Liang Xinyi , Xu Hao
Published: November 2017

With the increasing proportion of the grid‐connected PV power generation, the uncertainties and difficult predictions of PV output make it more difficult to deploy the distribution network. Firstly, the photovoltaic output interval model is established based on the light intensity which is approximate satisfied Beta distribution. Secondly, based on the empirical mode decomposition, the sparse Bayesian learning method and the load forecasting method, the load demand forecasting interval model is established. On this basis, a reliability‐economic oriented optimal dispatch model for the distribution network is proposed, which takes into account the prediction range of PV output and load demand. Then, based on fuzzy sampling method and multi‐objective particle swarm optimisation algorithm, a method to solve the proposed model is presented. Finally, simulation results show the effectiveness of the method.
Scheme to improve the load characteristics in DC distribution networks based on optimal allocation of energy storage systems
Authors: Song Guobing , Huang Xinghua , Wang Ting , Gu Yaobin
Published: November 2017

The load characteristics are a crucial factor that affects the stable operation of the power system. In this study, characteristics of representative loads in future DC distribution networks are investigated and then extrapolated to the synthetic load profile. It is revealed that the system stability might be jeopardised by the DC load characteristics. Then a scheme to improve the DC load characteristics is proposed using the energy storage system (ESS). The coordination between the ESS and the load power is discussed and then the optimal allocation of the ESS is presented. The allocation scheme achieves a trade‐off between the investment efficiency and the ESS functionality. The case studies show that the load characteristics are improved by the proposed scheme. The load power is smoothened and possesses voltage‐supporting abilities. The DC voltage varies smoothly in the given range with an increased safety margin.
Antimicrobial effect of silver nanoparticles (AgNPs) and their mechanism – a mini review
Authors: Kalwar Kaleemullah , Shan Dan
Published: November 2017

Silver nanoparticles (AgNPs) are widely utilised in the industry and health care. This review demonstrates an exhaustive report on the toxicity of AgNPs towards pathogenic microbes. AgNPs are the most abundant antimicrobial agent for bacteria than other species and less harmful to human cells than to bacterial cells. This report suggests the relatively high acute toxicity of AgNPs to the microorganism. In addition, the toxicity mechanism of AgNPs is briefly discussed.
YORP and Yarkovsky effects in asteroids (1685) Toro, (2100) Ra-Shalom, (3103) Eger, and (161989) Cacus
Authors: Ďurech J. , Vokrouhlický D. , Pravec P. , Hanuš J. , Farnocchia D. , Krugly Yu. N. , Inasaridze R. Y. , Ayvazian V. R. , Fatka P. , Chiorny V. G. , Gaftonyuk N. , Galád A. , Groom R. , Hornoch K. , Kučáková H. , Kušnirák P. , Lehký M. , Kvaratskhelia O. I. , Masi G. , Molotov I. E. , Oey J. , Pollock J. T. , Shevchenko V. G. , Vraštil J. , Warner B. D.
Published: November 2017

Context. The rotation states of small asteroids are affected by a net torque arising from an anisotropic sunlight reflection and thermal radiation from the asteroids’ surfaces. On long timescales, this so-called YORP effect can change asteroid spin directions and their rotation periods.

Aims. We analyzed lightcurves of four selected near-Earth asteroids with the aim of detecting secular changes in their rotation rates that are caused by YORP or at least of putting upper limits on such changes.

Methods. We use the lightcurve inversion method to model the observed lightcurves and include the change in the rotation rate dω/ dt as a free parameter of optimization. To enlarge the time line of observations and to increase the sensitivity of the method, we collected more than 70 new lightcurves. For asteroids Toro and Cacus, we used thermal infrared data from the WISE spacecraft and estimated their size and thermal inertia by means of a thermophysical model. We also used the currently available optical and radar astrometry of Toro, Ra-Shalom, and Cacus to infer the Yarkovsky effect.

Results. We detected a YORP acceleration of dω/ dt = (1.9 ± 0.3) × 10-8 rad d-2 for asteroid Cacus. The current astrometric data set is not sufficient to provide detection of the Yarkovsky effect in this case. For Toro, we have a tentative (2σ) detection of YORP from a significant improvement of the lightcurve fit for a nonzero value of dω/ dt = 3.0 × 10-9 rad d-2. We note an excellent agreement between the observed secular change of the semimajor axis da/ dt and the theoretical expectation for densities in the 2–2.5 g cm-3 range. For asteroid Eger, we confirmed the previously published YORP detection with more data and updated the YORP value to (1.1 ± 0.5) × 10-8 rad d-2. We also updated the shape model of asteroid Ra-Shalom and put an upper limit for the change of the rotation rate to | dω/ dt | ≲ 1.5 × 10-8 rad d-2. Ra-Shalom has a greater than 3σ Yarkovsky detection with a theoretical value consistent with observations assuming its size and/or density is slightly larger than the nominally expected values. Using the convex shape models and spin parameters reconstructed from lightcurves, we computed theoretical YORP values and compared them with those measured. They agree with each other within the expected uncertainties of the model.
Ball-Milling Promoted Monobromination Reactions: One-pot Regioselective Synthesis of Aryl Bromides and α-Bromoketones by NBS and Recyclable MCM-41-SO3H at Room Temperature
Authors: Ghanbari N. , Ghafuri H. , Zand H. , Eslami M.
Published: November 2017

An effective approach to monobromination reactions utilizing room temperature ball-milling is introduced for the synthesis of aryl bromides and bromoketones with N-bromosuccinimide (NBS) and MCM-41-SO3H. Advantages of this technique are short reaction times and high regioselectivity. In contrast to other techniques using microwaves, ultrasound, or ionic liquids, handling of sensitive materials is possible and furthermore, this method has advantages over other solvent-free techniques that require a higher reaction temperature for high yield of products.
Eine seltene Differenzialdiagnose von chronischem Husten
Authors: Dicker Michael , Schneider Tino , von Kempis Johannes , Diethelm Markus
Published: November 2017

Anamnese und klinischer Befund Wir berichten über einen 62-jährigen Patienten mit trockenem Husten seit 3 Monaten, Fieber, einer Allgemeinsymptomatik und erhöhten Entzündungswerten.

Untersuchungen Im Vorfeld ließ sich trotz umfangreicher Diagnostik keine infektiöse, neoplastische oder rheumatologische Diagnose stellen. Die Bronchoskopie mit bronchoalveolärer Lavage zeigte eine Lymphozytose. Im 18F-FDG-PET/CT fiel eine vermehrte Glukoseaufnahme in der gesamten Aorta mit ihren primären Ästen auf.

Diagnose, Therapie und Verlauf Wir diagnostizierten eine Großgefäßvaskulitis, vereinbar mit einer extrakraniellen Variante einer Riesenzellarteriitis (RZA). Nach Etablierung einer immunsuppressiven Therapie fand sich ein gutes klinisches Ansprechen und eine Regredienz der Entzündungswerte.

Folgerung Bei älteren Patienten mit Fieber, Husten und Allgemeinsymptomatik sollte differenzialdiagnostisch an eine RZA gedacht werden, auch wenn „klassische" Symptome fehlen. Respiratorische Symptome kommen als alleiniges Erstsymptom in ca. 4 %, zusammen mit klassischen Symptomen in ca. 9 % der Fälle mit RZA vor.Bei der Abklärung unklarer Entzündungszustände kommt dem 18F-FDG-PET/CT eine immer größere Bedeutung zu.
Primäres intraokuläres Lymphom: Relevanz der diagnostischen Vitrektomie
Authors: Le Guin Claudia , Metz Klaus , Bornfeld Norbert
Published: November 2017

Primär intraokuläre Lymphome sind sehr seltene Tumoren, die sich noch weiter in primär vitreoretinale und die noch viel selteneren primär uvealen Lymphome unterteilen lassen. In den letzten Jahrzehnten hat die Inzidenz des primär vitreoretinalen Lymphoms (PVRL) deutlich zugenommen. Die differenzialdiagnostische Abgrenzung zur posterioren Uveitis ist mitunter schwierig und daher kommt es in einigen Fällen zur verschleppten Diagnosestellung mit einer verzögerten Therapieeinleitung. Dies ist insbesondere deshalb fatal, weil das primär vitreoretinale Lymphom häufig mit dem primären ZNS-Lymphom assoziiert ist. Goldstandard zur Diagnosesicherung vor Therapieeinleitung ist der zytologische bzw. histologische Nachweis von Lymphomzellen. Hierzu wird eine diagnostische Vitrektomie mit Glaskörperbiopsie, evtl. kombiniert mit einer transretinalen Biopsie, durchgeführt. Zytokinanalyse, Durchflusszytometrie sowie molekulare Diagnostik sind lediglich ergänzende Maßnahmen, sofern genügend Probenmaterial vorhanden ist. Sobald die Diagnose eines Lymphoms gestellt ist, muss in interdisziplinärer Zusammenarbeit zwischen Onkologen und Ophthalmologen ein Therapiekonzept erarbeitet werden.
1.1.3 Synthesis of N-Heterocyclic Carbenes and Their Precursors
Authors: Huynh H. E. , Yuan D.
Published: November 2017

An overview of common methodologies for the preparation of free N-heterocyclic carbenes (NHCs) and their respective precursors is given. In addition to classical five-membered NHCs, examples of less-explored non-classical NHCs, including mesoionic and ring-expanded species, are also described. Experimental procedures reported in the primary literature are included for selected key compounds.
1.4.6 Hydrothiolation, Hydroalkoxylation, and Hydroaryloxylation
Authors: de Frémont P.
Published: November 2017

Hydrothiolation, hydroalkoxylation, and hydroaryloxylation reactions of carbon–carbon triple or double bonds, which belong to the broader family of hydroelementation reactions, conveniently lead to the formation of vinyl sulfides, alkyl sulfides, vinyl ethers, or alkyl ethers. Well-defined complexes of late transition metals with N-heterocyclic carbene ligands can efficiently promote these reactions under milder conditions and with better stereo- and regiocontrol compared to other methods employing free radicals or strong acids/bases.
2.1.2 Ring-Closing Metathesis
Authors: Broggi J. , Clavier H.
Published: November 2017

This chapter describes the use of ruthenium alkylidene complexes bearing N-heterocyclic carbene ligands as catalysts for the preparation of cyclic compounds (from 5- to 33-membered rings) by metathesis. Also included are examples of asymmetric metathesis using catalysts bearing chiral N-heterocyclic carbenes.
2.3 Cyclization Reactions
Authors: Zhong Y. , Felten S. , Louie J.
Published: November 2017

This chapter presents a detailed overview of current research into N-heterocyclic carbene (NHC) coordinated, transition-metal-catalyzed cyclization reactions. Highly efficient and economical access to pharmacologically relevant moieties, such as carbo- and heterocycles, is crucial in synthetic chemistry. Though cyclizations are atom-economical, historically harsh reaction conditions, poor substrate tolerance, and low product selectivity severely limited the practicality of such reactions. However, transition-metal catalysts based on copper, gold, palladium, nickel, rhodium, cobalt, and iron have allowed for the rapid synthesis of cyclization products in good to high yield and with high selectivity. In addition, these cyclizations tolerate starting materials bearing a variety of functional groups. Symmetric and asymmetric NHC ligands have proven to be critical for success in generating efficient transition-metal based catalytic systems. The electronic and steric diversity of NHC ligands allows for the fine-tuning of the transition-metal catalyst, which has resulted in effective [n + m]-cycloaddition reactions, inter- and intramolecular cycloisomerization reactions, and rearrangement reactions.
Lessons from attempting to backsource a government IT system
Authors: Petalidis Nicholaos
Published: November 2017

Backsourcing is not a common term and refers to the process of taking back development of a system that was previously outsourced. Even though the term is not a common one, the process that it describes is. Businesses try to reverse outsourcing and start insourcing all the time. The process however is not cost free and certainly is not paved with roses. Herein we report from our own experience of trying to backsource the development and maintenance of a large information system, focusing on the technical problems encountered. The novel aspect of this paper is that it is one of the few that provide insights into the specifics that one has to include in any outsourcing contract, for backsourcing to be possible.
Energy planning model with renewable energy using optimization multicriteria techniques for isolated rural communities: Cajamarca province, Peru
Authors: Falcón-Roque Eder Jesús , Marcos Martín Francisco , Pascual Castaño Cristina , Domínguez-Dafauce Luis Carlos , Bastante Flores Francisco Javier
Published: November 2017

One of the seventeen Sustainable Development Goals (SDGs) introduced by the United Nations is SDG 7, Affordable and Clean Energy: “to ensure access to affordable, reliable and modern energy for all.” Peru is one of the Latin America and Caribbean countries that has signed this commitment. The Peruvian government encourages the supply of electricity from renewable energy sources to isolated rural communities, and renewable energy is considered in the country energy planning. This paper presents an energy planning model based on multicriteria optimization techniques, named SEPLAN (Sustainable Energy Planning). The SEPLAN model allows the incorporation of objectives that could be in conflict: for example, economic, environmental, or social objectives, as well as universal access to energy. In this model, six objective functions were established: replaceable amounts of fossil energy; CO2, NOX, and SO2 avoidable emissions; cost minimization; and universal access to energy in isolated rural communities. Linear programming was applied to the six objective functions, and optimal solutions were chosen for each one. The efficient solutions were found with compromise programming, and Chebysev distance (L∞) was chosen as the Pareto optimal solution. The proposed model was applied in Cajamarca province, Peru. Cajamarca has the lowest electrification rate of the country due to the very high dispersion of households of rural communities. The results for the analysed scenarios provided the prioritization of the energy alternatives considered. When encouraging the objective function related to universal access to energy in isolated rural communities, photovoltaic solar energy was the priority in power energy generation. Thereby, the model could become a useful tool for decision makers.
An exploratory study of heterotrophic protists of the mesopelagic Mediterranean Sea
Authors: Dolan John R , Ciobanu Maria , Marro Sophie , Coppola Laurent
Published: November 2017

Is there a mesopelagic protist fauna composed of species different from that of the overlying surface community? Does the mesopelagic community show seasonal changes in abundances and species composition? We addressed these questions by considering three distinct groups in which species identification is relatively unambiguous: tintinnid ciliates, phaeodarian radiolarians, and amphisolenid dinoflagellates. We sampled weekly at 250 m and 30 m depth from January to June a deep-water coastal site characterized by seasonal changes in water column structure; notably, in winter the mixed layer extends down into mesopelagic depths. We found a deep-water community of tintinnid ciliates comprised of forms apparently restricted to deep waters and species also found in the surface layer. This latter group was dominant during the winter mixis period when tintinnid concentrations were highest and subsequently declined with water column stratification. Phaeodarian radiolarians and the amphisolenid dinoflagellates were regularly found in deep samples but were largely absent from surface water samples and showed distinct patterns in the mesopelagic. Phaeodarian radiolarians declined with water column mixing and then increased in concentration with water column stratification whilst amphisolenid dinoflagellates concentrations showed no pattern but species composition varied. We conclude that for all three protists groups there appear to be both distinct mesopelagic forms and seasonal patterns.