bluuebunny/crossref_metadata_2025 huggingface dataset:
Sub‐synchronous oscillation analysis of complicated power grid incorporating wind farms with different types
Authors: Yang Fan , Shi Libao , Ni Yixin
Published: November 2017

A complicated test system with integration of doubly‐fed induction generator (DFIG)‐based and permanent magnet synchronous generator (PMSG)‐based wind farms is built up in this study to explore and exploit the interactions between DFIG unit and PMSG unit on the issue of sub‐synchronous oscillation (SSO). With detailed modelling of wind farm units, transmission lines and loads, the SSO modes are elaborately analysed through eigenvalue analysis and participation factor methods. The level and position of series compensated lines are discussed leading to some useful comments and suggestions. Besides, the power outputs of the two wind farm types are compared to investigate their potential influences on the oscillation, and the most influential proportional–integral parameters producing the potential risks of oscillation are chosen out.
Accurate fault location of complex distribution network with distributed generators
Authors: Li Weijian , Guo Chuangxin , Jin Yu , Gong Xiao
Published: November 2017

For the complex distribution network with lots of branches and distributed power supply, a fault location method based on voltage sag information is proposed. First, the equivalent model is established for the distributed power source. Then the fault current vector is obtained by using the node impedance matrix and the voltage vector recorded by the distributed power supply access point before and during the fault. Finally, the faulted node is determined by comparing fault current deviation values. Through the simulation analysis of an actual complex distribution network, the validity and efficiency of the proposed method is verified, and the influence of load fluctuation and transition resistance is small.
Coordinated economic dispatch and cost allocation of cooperative multi‐microgrids
Authors: Xiao Hao , Du Yan , Pei Wei , Kong Li
Published: November 2017

This study models the cooperative behaviours of multi‐microgrid (MMG) in order to achieve higher energy efficiency and operation economy. Under the framework of cooperative game theory, microgrid members aggregate as one grand coalition and are scheduled via coordinated economic dispatch. Furthermore, a Nash–Harsanyi (N–H) cost allocation scheme is proposed to ensure a fair cost sharing among the players. Considering the combinatorial explosive characteristic of the cost allocation problem, a bi‐level programming algorithm is designed to quickly pin the N–H share. Case studies with a MMG system demonstrate the advantages of microgrid cooperation and the robustness of the formulated grand coalition, as well as the computation efficiency of the proposed cost sharing method.
Air conditioner fast dispatching model based on load aggregator and direct load control
Authors: Wang Xinwei , Gong Yanfeng
Published: November 2017

In recent years, the whole society's electricity demand showed a sustained and rapid growth trend. The power supply is difficult to meet the demand. During the load peak period in summer, the proportion of air‐conditioning load is as high as 30–50%. This kind of load will lead to further widening of the peak‐valley difference and bring hidden danger to the operation of the power grid. The interaction between users, load aggregator and grid dispatch centre are introduced first and then, the design contract details between the user and load aggregator which has great significance on practical applications. Two dispatching models based on load aggregator and direct load control are put forward, which incorporates the electric excitation and electricity price response, to ensure safe and stable operation of power grids during the peak period. On the basis of grid stable operation, achieving costs optimal. Finally, solving results show that the coordinated dispatching strategy the authors proposed could not only effectively reduce the peak load of the system, but could also fast and precisely dispatch loads when system faults occur.
Hot embossing of anodic aluminium oxide on high‐density polyethylene: a deeper understanding based on hard surface coating
Authors: Boonniyom Suchada , Osotchan Tanakorn , Subannajui Kittitat
Published: November 2017

A thick anodic aluminium oxide (AAO) was used as a laminated hard coating film on high‐density polyethylene (HDPE) without a binder. This thick alumina surface has a large number of polymeric nanofibers rooting inside which makes it a composite between polymer fibre and alumina. The AAO‐coated film was crystalline gamma‐Al2O3 and its Vickers hardness was higher than super alloy and martensitic stainless steel which has a durable and wear resistance surface despite the substrate is still a lightweight polymer. The film surface was firmly adhered to the polymer substrate. Therefore, it can be applied in many applications which require an extreme hard coating such as a transparent hard film or a special made polymer knife in which the sharpness is hardly worn out.
Global enhancement and structure formation of the magnetic field in spiral galaxies
Authors: Khoperskov Sergey A. , Khrapov Sergey S.
Published: November 2017

In this paper we study numerically large-scale magnetic field evolution and its enhancement in gaseous disks of spiral galaxies. We consider a set of models with the various spiral pattern parameters and the initial magnetic field strength with taking into account gas self-gravity and cooling and heating processes. In agreement with previous studies we find out that galactic magnetic field is mostly aligned with gaseous structures, however small-scale gaseous structures (spurs and clumps) are more chaotic than the magnetic field structure. In spiral arms magnetic field often coexists with the gas distribution, in the inter-arm region we see filamentary magnetic field structure. These filaments connect several isolated gaseous clumps. Simulations reveal the presence of the small-scale irregularities of the magnetic field as well as the reversal of magnetic field at the outer edge of the large-scale spurs. We provide evidences that the magnetic field in the spiral arms has a stronger mean-field component, and there is a clear inverse correlation between gas density and plasma-beta parameter, compared to the rest of the disk with a more turbulent component of the field and an absence of correlation between gas density and plasma-beta. We show the mean field growth up to 3−10 μG in the cold gas during several rotation periods (500−800 Myr), whereas ratio between azimuthal and radial field is equal to 4/1. We find an enhancement of random and ordered components of the magnetic field. Mean field strength increases by a factor of 1.5−2.5 for models with various spiral pattern parameters. Random magnetic field component can reach up to 25% from the total strength. By making an analysis of the time-dependent evolution of the radial Poynting flux, we point out that the magnetic field strength is enhanced more strongly at the galactic outskirts which is due to the radial transfer of magnetic energy by the spiral arms pushing the magnetic field outward. Our results also support the presence of sufficient conditions for the development of magnetorotational instability at distances >11 kpc after 300 Myr of evolution.
Chelation-Assisted C–H and C–C Bond Activation of Allylic Alcohols by a Rh(I) Catalyst under Microwave Irradiation
Authors: Jun Chul-Ho , Lee Chang-Hee
Published: November 2017

Chelation-assisted Rh(I)-catalyzed ketone synthesis from allylic alcohols and alkenes through C–H and C–C bond activations under microwave irradiation was developed. Aldimine is formed via olefin isomerization of allyl alcohol under Rh(I) catalysis and condensation with 2-amino-3-picoline, followed by continuous C–H and C–C bond activations to produce a dialkyl ketone. The addition of piperidine accelerates the reaction rate by promoting aldimine formation under microwave conditions.
Thrombozytose und Thrombozytopenie – Ursachen und klinische Bedeutung
Authors: Wille Kai , Sadjadian Parvis , Griesshammer Martin
Published: November 2017

Due to the central role of platelets in hemostasis, the clinical relevance of quantitative changes in platelet counts (< 150 G/l or > 450 G/l) may be significant. Thrombopoesis (= production of platelets) occurs in the bone marrow, and the hormone thrombopoetin takes control on its regulation.

In thrombocytosis, primary causes have to be distinguished from the far more common reactive (= secondary) reasons. The most important form of primary thrombocytosis occurs in myeloproliferative neoplasms especially in essential thrombocythemia (ET). Clinically, increased thrombophilia, microcirculatory disturbances as well as an increased hemorrhagic diathesis occur in patients with myeloproliferative neoplasms. According to the WHO diagnosis criteria 2016 standard diagnostic procedure in myeloproliferative neoplasms includes bone marrow biopsy and the detection of one of the acquired and typical MPN mutations in the JAK2, MPL or CALR gene.

In contrast, patients with thrombocytopenia more often suffer from bleeding complications, however, in antiphospholipid syndrome or thrombotic microangiopathy (TMA) thrombotic events occur in spite of a low platelet count. Generally it makes sense to differentiate between pathological changes in thrombopoesis and the various causes of increased peripheral platelet turnover. Concerning differential diagnosis a careful anamnesis is very important in order to get hints like drugs associated with thrombocytopenia, signs of infection or autoimmune disorders. As an initial diagnostic approach we recommend examination of the blood smear in order to exclude pseudothrombocytopenia or disorderes like thrombotic microangiopathy, myelodysplasia or other hematological diseases.
Leukopenie – ein diagnostischer Leitfaden für die Praxis
Authors: Christen Deborah , Brümmendorf Tim , Panse Jens
Published: November 2017

Reasons for leukopenia can be numerous. To get close to the diagnosis it’s always useful to check previous blood counts of the patient to get a feeling for the dynamic development of the leukopenia. Furthermore, it’s important to check the red blood cell count and platelet count as well; a bi- or a pancytopenia usually implies an insufficient production in the bone marrow. Nevertheless, a manual counted peripheral blood smear is an essential step towards the right diagnosis in leukopenia: Beside cell counts of the single subgroups of leucocytes it also provides information on potential causes such as dysplasia.

Leukopenia can be life-threatening for the patient especially if the patient presents with an agranulocytosis and fever: In this case admission is mandatory and the patient has to be treated immediately with broad-spectrum antibiotics to reduce mortality.
Masern in Deutschland – Epidemiologie und Management
Authors: Matysiak-Klose Dorothea , Wicker Sabine ,   für die Nationale Verifizierungskommission Masern Röteln (NAVKO) in Deutschland
Published: November 2017

Measles are one of the most contagious diseases of mankind. Measles incidence has declined worldwide since the introduction of vaccinations. Due to low numbers of measles cases in countries with high vaccination rates the population is not aware of possible complications of measles any more. Measles elimination is an important goal set by all regions of the World Health Organization. However, it remains a challenge for Germany and other European countries. Because of a high proportion of susceptibles in specific population and age groups outbreaks take place in Germany every year after importation of the virus. More than 50 % of measles cases are 20 years and older. However, the highest incidences have been seen in two-year-olds since several years. In addition to epidemiological findings such as case numbers and risk groups, genotyping permits e. g. an assessment of the endemic circulation of viruses. Suspicion of a measles case should result in immediate and consistent measures.
1.2.1 Suzuki–Miyaura Coupling
Authors: Chetcuti M. J.
Published: November 2017

The Suzuki–Miyaura reaction of an organoboronic acid (usually an arylboronic acid) with an organo halide (typically an aryl halide) to generate a new C—C bond is one of the most valuable methods for C–C bond formation. Since the ascension of N-heterocyclic carbenes (NHCs) to occupy the position of key ligands in the repertoire of synthetic organometallic chemists, metal complexes based on these ligands have become important as catalysts for the Suzuki–Miyaura reaction. Most metal–NHC complexes used for Suzuki–Miyaura coupling are based on palladium, but an increasingly important contribution is being played by nickel-based complexes. This chapter reviews the state of the art of Suzuki–Miyaura coupling reactions catalyzed by metal–NHC complexes, with a focus on systems with broad applicability, and especially those that can be applied to “difficult” reactions such as the coupling of aryl chlorides or sterically hindered substrates. The relatively undeveloped fields of asymmetric Suzuki–Miyaura reactions and Suzuki–Miyaura reactions in water, both catalyzed by metal–NHC complexes, are also covered.
1.2.3 The Buchwald–Hartwig Reaction
Authors: Martin A. R.
Published: November 2017

This chapter covers the use of N-heterocyclic carbenes as ligands in the Buchwald–Hartwig reaction. The most efficient and convenient palladium- and nickel-based catalytic systems able to promote the C—N bond formation between various amines and (het)aryl halides or pseudohalides are reviewed.
1.4.3 Hydrosilylation
Authors: Baudrenghien L. , Markó I. E.
Published: November 2017

Hydrosilylation of alkenes and alkynes, promoted by various generations of now commercially available (or easily formed) platinum–N-heterocyclic carbene complexes, enables efficient access to valuable silanes. Under optimal conditions, this process constitutes an atom economical, solvent-free, green process yielding terminal alkylsilanes and β-(E)-vinylsilanes in a rapid, efficient, and selective manner.
1.4.8 Hydroarylation
Authors: Nakao Y.
Published: November 2017

This chapter describes the hydroarylation and hydrohetarylation of alkenes and alkynes catalyzed by nickel–N-heterocyclic carbene complexes.
1.4.10 Hydroformylation
Authors: Trzeciak A. M.
Published: November 2017

Hydroformylation of alkenes is one of the most important catalytic industrial processes performed in a homogeneous system. During hydroformylation, aldehydes are formed from alkenes and syngas (a mixture of hydrogen and carbon monoxide) in the presence of a metal complex, usually based on rhodium or cobalt. In this chapter, the catalytic application of metal complexes with N-heterocyclic carbene (NHC) ligands in hydroformylation is discussed.
2.1.3 Cross Metathesis
Authors: Jana A. , Malecki P. , Grela K.
Published: November 2017

During the past two decades, among all the types of transition-metal-catalyzed reaction, olefin metathesis has become arguably the most powerful synthetic tool for carbon–carbon bond formation. The reason for this is undoubtedly the development of well-defined functional-group-tolerant N-heterocyclic carbene (NHC) based ruthenium alkylidene catalysts. Among the types of olefin metathesis, cross metathesis is probably the most useful due to its numerous advantages and has found a wide range of application in almost every field of organic synthesis. Introduction of NHCs has made the ruthenium catalysts more stable and more functional group tolerant. The efficiency and selectivity of the reaction and the activity of the catalyst are three key issues that need to be considered in cross metathesis and introduction of NHC-based ruthenium catalysts addresses all three. This chapter focuses on different types of cross metathesis, performed under different conditions and using different NHC-based catalysts.
2.1.5 Alkene Metathesis Based Polymerization
Authors: Liu J. , Johnson J.
Published: November 2017

Alkene metathesis based polymerizations that rely on metal complexes with N-heterocyclic carbene (NHC) ligands are discussed in this chapter. Particular emphasis is placed on novel polymer microstructures, architectures, and applications that have been enabled by NHC–metal complexes. Applications of ruthenium–NHC initiated ring opening metathesis polymerization (ROMP) for the synthesis of block copolymers, branched polymers, stereocontrolled polymers, and cyclic polymers are described. Ruthenium–NHC catalyzed acyclic diene metathesis polymerization (ADMET) and cyclopolymerization are also discussed, along with alkene metathesis polymerizations using tungsten– and molybdenum–NHC complexes.
2.2 Polymerization, Oligomerization, and Telomerization Involving N-Heterocyclic Carbenes as Ligands or Initiators
Authors: Costabile C.
Published: November 2017

This chapter is an overview of recent developments in polymerization and oligomerization of alkenes and cyclic esters involving N-heterocyclic carbenes, both as ligands in organometallic catalysts and as organocatalysts. Telomerization reactions catalyzed by N-heterocyclic carbene–palladium complexes are also briefly discussed.
2.7.3 Catalytic Systems Featuring Ionically Tagged N-Heterocyclic Carbene Ligands
Authors: Schmid T. , Crevisy C. , Basle O. , Mauduit M.
Published: November 2017

Since the discovery of N-heterocyclic carbenes (NHCs), their unique properties as ligands in organometallic chemistry have enabled the synthesis of a myriad of novel metal complexes. Thanks to the facile modulation of this class of ligands, they can be easily functionalized with ionic tags, which has proven to be useful for various applications. Notably, such groups have enabled the immobilization of metal complexes on a variety of supports, and recyclable catalysis could be realized. This chapter describes organometallic species featuring ionically-tagged NHCs for such applications, focusing on catalytic systems that show the best performance in terms of versatility and reusability.
2.8 Recent Advances in N-Heterocyclic Carbene Organocatalysis
Authors: Davies A. , Smith A. D.
Published: November 2017

In recent years, organocatalysis has seen a rapid rise in popularity and this has led to a subsequent increase in the research output of the area, with organocatalysis by N-heterocyclic carbenes (NHCs) playing a significant role. Beginning with the benzoin condensation, through the work of Breslow and others to modern, asymmetric protocols, NHC organocatalysis has a rich history, which has been covered in many reviews. The focus of this chapter is on recent advances within the area of NHC organocatalysis, offering a brief historical perspective and highlighting what the authors believe to be some of the key advances made within recent times, both in terms of novel processes and significant advancements on previously documented reactions.
Quantum size effect on the heat capacity of nickel nanolattice
Authors: Singh J. , Tarachand  , Samatham S. S. , Venkateshwarlu D. , Kaurav Netram , Ganesan V. , Okram G. S.
Published: November 2017

Nearly exponentially decaying heat capacity was observed exceptionally in a well-characterized naturally assembled hexagonal closed packed lattice of 4.0 nm nickel nanoparticles (NPs). It was also associated with quantum jumps. These were however not observed in other NP sizes and have negligible effects of high magnetic fields. Magnetic susceptibilities in contrast revealed the evolution of quantum size effects with a decrease in particle size. They exhibited sharp rise below about 30 K and vestiges of saturations below 5 K. The sharp rise was explained by Curie-like characteristics of odd electrons, while the saturations tend towards the orthogonal even-like case.
Low-frequency optical phonon modes and carrier mobility in the halide perovskite CH3NH3PbBr3 using terahertz time-domain spectroscopy
Authors: Zhao Daming , Skelton Jonathan M. , Hu Hongwei , La-o-vorakiat Chan , Zhu Jian-Xin , Marcus Rudolph A. , Michel-Beyerle Maria-Elisabeth , Lam Yeng Ming , Walsh Aron , Chia Elbert E. M.
Published: November 2017

As a light absorber in photovoltaic applications, hybrid organic-inorganic halide perovskites should have long and balanced diffusion lengths for both the separated electrons and holes before recombination, which necessitates high carrier mobility. In polar semiconductors, the room-temperature carrier mobility is often limited by the scattering between carriers and the lowest-frequency optical phonon modes. Using terahertz time-domain spectroscopy, we examine the temperature evolution of these phonon modes in CH3NH3PbBr3 and obtained high carrier mobility values using Feynman's polaron theory. This method allows us to estimate the upper limit of carrier mobilities without the need to create photogenerated free carriers, and can be applied to other heteropolar semiconductor systems with large polarons.
Effect of nozzle-exit conditions on the near-field characteristics of a transverse liquid jet in a subsonic uniform cross airflow
Authors: Broumand Mohsen , Birouk Madjid
Published: November 2017

Several tapered- and sharp-edge nozzles with different exit diameters were used to investigate their effect on the near-field characteristics of a liquid jet injected transversely into a subsonic uniform cross airflow including a jet’s structure, column trajectory, and its breakup length. The experimental results demonstrated that at a low range of jet velocity, the axial turbulence intensity of a liquid jet issuing from a sharp-edge nozzle is greater than that of a tapered-edge nozzle. This resulted in a more irregular surface of the liquid column injected from a sharp-edge nozzle. However, the presence of hydraulic flip in the case of a sharp-edge nozzle at high jet velocity caused a reduction in the axial turbulence intensity of the injected liquid jet which has a smoother surface. Prior to the occurrence of hydraulic flip, the column trajectory of a liquid jet issuing from a tapered-edge nozzle is similar to that of a sharp-edge nozzle. However, the jet issuing from the latter penetrates farther than the former under hydraulic flip conditions. The presence of hydraulic flip increases the breakup length of a liquid jet. Furthermore, the present experiments allowed estimating the discharge coefficient of each nozzle by comparing with the mathematical correlations developed in our previous studies for predicting the column trajectory and breakup length of a transverse liquid jet. This allowed extending the applicability of these correlations to account for the effect of nozzle’s exit conditions on the near-field characteristics of a transverse liquid jet.
Modifying hydrogen-bonded structures by physical vapor deposition: 4-methyl-3-heptanol
Authors: Young-Gonzales A. R. , Guiseppi-Elie A. , Ediger M. D. , Richert R.
Published: November 2017

We prepared films of 4-methyl-3-heptanol by vapor depositing onto substrates held at temperatures between Tdep = 0.6Tg and Tg, where Tg is the glass transition temperature. Using deposition rates between 0.9 and 6.0 nm/s, we prepared films about 5 μm thick and measured the dielectric properties via an interdigitated electrode cell onto which films were deposited. Samples prepared at Tdep = Tg display the dielectric behavior of the ordinary supercooled liquid. Films deposited at lower deposition temperatures show a high dielectric loss upon heating toward Tg, which decreases by a factor of about 12 by annealing at Tg = 162 K. This change is consistent with either a drop of the Kirkwood correlation factor, gk, by a factor of about 10, or an increase in the dielectric relaxation times, both being indicative of changes toward ring-like hydrogen-bonded structure characteristic of the ordinary liquid. We rationalize the high dielectric relaxation amplitude in the vapor deposited glass by suggesting that depositions at low temperature provide insufficient time for molecules to form ring-like supramolecular structures for which dipole moments cancel. Surprisingly, above Tg of the ordinary liquid, these vapor deposited films fail to completely recover the dielectric properties of the liquid obtained by supercooling. Instead, the dielectric relaxation remains slower and its amplitude much higher than that of the equilibrium liquid state, indicative of a structure that differs from the equilibrium liquid up to at least Tg + 40 K.
Operation of a sub-terahertz CW gyrotron with an extremely low voltage
Authors: Bratman V. L. , Fedotov A. E. , Fokin A. P. , Glyavin M. Yu. , Manuilov V. N. , Osharin I. V.
Published: November 2017

Decreasing the operating voltage for medium-power sub-terahertz gyrotrons aimed at industrial and scientific applications is highly attractive, since it allows size and cost reduction of the tubes and power supply units. In this paper, we examine such an opportunity both numerically and experimentally for the fundamental cyclotron resonance operation of an existing gyrotron initially designed for operation at the second cyclotron harmonic with a relatively high voltage. Simulations predict that output power higher than 10 W can be produced at the fundamental harmonic at voltages less than 2 kV. To form a low-voltage helical electron beam with a sufficiently large pitch-factor, a positive voltage was applied to the first anode of the gyrotron three-electrode magnetron-injection gun with a negative voltage at the cathode. CW gyrotron operation at voltages down to 1.5 kV has been demonstrated at a frequency about of 256 GHz.
A universal design of field-effect-tunable microfluidic ion diode based on a gating cation-exchange nanoporous membrane
Authors: Liu Weiyu , Ren Yukun , Tao Ye , Yao Bobin , Liu Ni , Wu Qisheng
Published: November 2017

Based on the continuum mechanics theory, we propose herein a universal design of microfluidic ionic diode based on external concentration polarization of a gating ion-selective medium embedded in the microfluidic network with four power terminals. This micro/nanofluidic hybrid chip employs a cation-exchange nanoporous membrane (CEM) coupled with both a control and output microfluidic channel. Under the action of a vertical electric field throughout the CEM, nanoscale surface conduction of excessive counterions within the charged nanopores is converted to the propagation of either enriched or depleted boundary toward the opposing electrode-terminal in phase with the electroconvective flow, thereby making an adjustment in the electrical conductance of output microchannel for achieving high-flux field-effect current control and diode functionality. Three basic working states, including the “on,” “transition,” and “off” statuses, are distinguished in different ranges of source voltage magnitude. The rectification factor of the proposed ionic circuit platform can attain one hundred-fold even at small source and gate voltages. The presented field-effect-tunable microfluidic ion diode is easily scalable, permits appreciable fluid flow due to an intrinsically small hydrodynamic resistance, and holds promise for producing high-flux ion current rectification in next-generation integrated circuits.
Effective interactions between inclusions in an active bath
Authors: Zaeifi Yamchi Mahdi , Naji Ali
Published: November 2017

We study effective two- and three-body interactions between non-active colloidal inclusions in an active bath of chiral or non-chiral particles, using Brownian dynamics simulations within a standard, two-dimensional model of disk-shaped inclusions and active particles. In a non-chiral active bath, we first corroborate previous findings on effective two-body repulsion mediated between the inclusions by elucidating the detailed non-monotonic features of the two-body force profiles, including a primary maximum and a secondary hump at larger separations that was not previously reported. We then show that these features arise directly from the formation, and sequential overlaps, of circular layers (or “rings”) of active particles around the inclusions, as the latter are brought to small surface separations. These rings extend to radial distances of a few active-particle radii from the surface of inclusions, giving the hard-core inclusions relatively thick, soft, repulsive “shoulders,” whose multiple overlaps then enable significant (non-pairwise) three-body forces in both non-chiral and chiral active baths. The resulting three-body forces can even exceed the two-body forces in magnitude and display distinct repulsive and attractive regimes at intermediate to large self-propulsion strengths. In a chiral active bath, we show that, while active particles still tend to accumulate at the immediate vicinity of the inclusions, they exhibit strong depletion from the intervening region between the inclusions and partial depletion from relatively thick, circular zones further away from the inclusions. In this case, the effective, predominantly repulsive interactions between the inclusions turn to active, chirality-induced, depletion-type attractions, acting over an extended range of separations.
Long-range dipolar order and dispersion forces in polar liquids
Authors: Besford Quinn Alexander , Christofferson Andrew Joseph , Liu Maoyuan , Yarovsky Irene
Published: November 2017

Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is “felt” between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied. When the structural order is compared with a dipolar dispersion force that arises from local co-operative enhancement of dipole moments, a strong agreement is found. Lifshitz theory of dispersion forces was compared with the structural order, where the theory is validated for all liquids that do not have significant local dipole correlations. For liquids that do have significant local dipole correlations, specifically liquid water, Lifshitz theory underestimates the dispersion force by a factor of 5–10, demonstrating that the force that leads to the increased structure in liquid water is missed by Lifshitz theory of van der Waals forces. We apply similar correlation functions to an ionic aqueous system, where long-range order between water’s dipole moment and a single chloride ion is found to exist at 20 Å of separation, revealing a long-range perturbation of water’s structure by an ion. Furthermore, we found that waters within the 1st, 2nd, and 3rd solvation shells of a chloride ion exhibit significantly enhanced dipolar interactions, particularly with waters at larger distances of separation. Our results provide a link between structures, dispersion forces, and specific ion effects, which may lead to a more robust understanding of solvation.
Focusing light through scattering media by polarization modulation based generalized digital optical phase conjugation
Authors: Yang Jiamiao , Shen Yuecheng , Liu Yan , Hemphill Ashton S. , Wang Lihong V.
Published: November 2017

Optical scattering prevents light from being focused through thick biological tissue at depths greater than ∼1 mm. To break this optical diffusion limit, digital optical phase conjugation (DOPC) based wavefront shaping techniques are being actively developed. Previous DOPC systems employed spatial light modulators that modulated either the phase or the amplitude of the conjugate light field. Here, we achieve optical focusing through scattering media by using polarization modulation based generalized DOPC. First, we describe an algorithm to extract the polarization map from the measured scattered field. Then, we validate the algorithm through numerical simulations and find that the focusing contrast achieved by polarization modulation is similar to that achieved by phase modulation. Finally, we build a system using an inexpensive twisted nematic liquid crystal based spatial light modulator (SLM) and experimentally demonstrate light focusing through 3-mm thick chicken breast tissue. Since the polarization modulation based SLMs are widely used in displays and are having more and more pixel counts with the prevalence of 4 K displays, these SLMs are inexpensive and valuable devices for wavefront shaping.
Distributed loss method to suppress high order modes in broad area quantum cascade lasers
Authors: Kaspi R. , Luong S. , Bate T. , Lu C. , Newell T. C. , Yang C.
Published: November 2017

We describe a method where the standard fabrication of broad area quantum cascade lasers is modified to provide a controlled amount of direct contact of device sidewalls with metal. We demonstrate that this provides sufficient levels of distributed losses to suppress the high order transverse modes in favor of the fundamental or near-fundamental transverse mode operation. We observe that the quantum cascade laser power and slope efficiency are degraded by a small amount, resulting in a large increase in brightness to accompany the power scaling.
Nonlinear electrostatic oscillations in a cold magnetized electron-positron plasma
Authors: Verma Prabal Singh , Adhyapak Tapan Chandra
Published: November 2017

We study the spatio-temporal evolution of the nonlinear electrostatic oscillations in a cold magnetized electron-positron (e-p) plasma using both analytics and simulations. Using a perturbative method, we demonstrate that the nonlinear solutions change significantly when a pure electrostatic mode is excited at the linear level instead of a mixed upper-hybrid and zero-frequency mode that is considered in a recent study. The pure electrostatic oscillations undergo phase-mixing nonlinearly. However, the presence of the magnetic field significantly delays the phase-mixing compared to that observed in the corresponding unmagnetized plasma. Using one dimensional particle-in-cell simulations, we then analyze the damping of the primary mode of the pure oscillations in detail and infer the dependence of the phase-mixing time on the magnetic field and the amplitude of the oscillations. The results are remarkably different from those found for the mixed mode study mentioned earlier. Exploiting the symmetry of the e-p plasma, we then explain a generalized symmetry of our non-linear solutions. The symmetry allows us to construct a unique nonlinear solution up to the second order which does not show any signature of phase-mixing but results in a nonlinear wave traveling at the upper-hybrid frequency. Our investigations have relevance for laboratory/astrophysical e-p plasmas.
The efficacy of monitoring techniques for detecting small mammals and reptiles in arid environments
Authors: Molyneux J. , Pavey C. R. , James A. I. , Carthew S. M.
Published: November 2017

Context Accurate surveying and monitoring of biodiversity provides essential baseline data for developing and implementing effective environmental management strategies. Land managers in arid zones face the challenge of managing vast, remote landscapes that support numerous cryptic species that are difficult to detect and monitor. Although researchers and land managers are using an increasingly wider variety of monitoring techniques to detect and monitor species, little is known of the relative effectiveness and comparative costs of these techniques. Aims The present study simultaneously assessed the efficacy of three popular monitoring techniques utilised in the spinifex sand plains of arid Australia, namely, live trapping, sign surveys and passive infrared (PIR)-camera trapping. Methods We explored variations in capture rates and species richness for each technique and compared initial and on-going costs of the techniques over time. Key results Sign surveys detected the greatest number of species and groups overall. Detectability of small mammals and reptiles, as a target group, was greater using PIR cameras, although the probability of detection by each technique varied among specific species. PIR cameras were initially the most expensive technique; however, the low ongoing costs of maintaining cameras in the field meant that they became the most cost effective after eight survey periods. Conclusions Each of the techniques tested here showed biases towards the detection of specific groups or species in the spinifex sand-plain habitat of Australia. Regardless, PIR cameras performed better at detecting the greatest diversity of target species and financially over time. Implications To accurately survey species across vast areas and climate variations, studies often extend over long time periods. Many long-term studies would be likely to benefit financially from the increased deployment of PIR cameras alongside or in place of live trapping surveys, with little impact on the ability to monitor the presence of most species in the region.
An inexpensive satellite-download GPS receiver for wildlife: field trial on black swans
Authors: Lehrke Rebecca M. , McGregor Lizzie , Dyer John , Stanley Margaret C. , Dennis Todd E.
Published: November 2017

Context Knowledge of the movements and space-use patterns of wildlife is crucial for implementation of effective conservation and management actions. Such information can be difficult to obtain, especially from hard-to-capture or far-ranging taxa. Global-positioning-system (GPS) receivers that have remote data-acquisition capability via satellite-communication networks offer an effective means of tracking highly mobile animals; however, often the equipment and operational costs of these devices are prohibitive. Aim To evaluate the operational performance and potential of an inexpensive, commercially available satellite-download GPS receiver that can be easily modified for use on wildlife, and to demonstrate its utility for revealing novel information on individual animal movements in an important wildlife management context. Methods We added external batteries and supplementary waterproofing to ‘off-the-shelf’ SPOT Trace® GPS receivers (~$120 USD; Spot LLC, Covington, LA) that transmit recorded location data to users through the Globalstar satellite network. We then deployed these devices on eight wild black swans (Cygnus atratus) inhabiting a large inland marine harbor adjacent to Auckland International Airport and assessed the GPS units’ operational performance and overall cost effectiveness. Key results During field trials with the tracking devices lasting up to 25 days we were able to collect thousands of precision location observations from the swans without the need for recapture. Cost-per-fix was only ~$0.04 USD – up to an order of magnitude lower than some satellite-download GPS receivers manufactured specifically for wildlife. We provide novel information about the swans’ patterns of activity, movement, space-use, habitat preferences and responses to actions taken by airport staff to scare problem individuals from threat zones. Conclusions User-modified satellite-download GPS devices can be a highly cost-effective means of tracking the movements of animals. Implications Knowledge of where and when swans present the greatest likely threat to air traffic and how they respond to displacement from restricted areas near the airport will be useful in devising threat-management plans. The ready availability of affordable remote-download GPS receivers will provide many new opportunities to study the movement and/or space-use patterns of wildlife and incorporate such information into a broad range of research and management programs.
UNC-45a helps cells manage their stress levels
Authors: Short Ben
Published: November 2017

The chaperone UNC-45a helps nonmuscle myosin II fold and assemble into contractile stress fibers.
Serial Participation and the Ethics of Phase 1 Healthy Volunteer Research
Authors: Walker Rebecca L , Cottingham Marci D , Fisher Jill A
Published: November 2017

Phase 1 healthy volunteer clinical trials—which financially compensate subjects in tests of drug toxicity levels and side effects—appear to place pressure on each joint of the moral framework justifying research. In this article, we review concerns about phase 1 trials as they have been framed in the bioethics literature, including undue inducement and coercion, unjust exploitation, and worries about compromised data validity. We then revisit these concerns in light of the lived experiences of serial participants who are income-dependent on phase 1 trials. We show how participant experiences shift attention from discrete exchanges, behaviors, and events in the research enterprise to the ongoing and dynamic patterns of serial participation in which individual decision-making is embedded in collective social and economic conditions and shaped by institutional policies. We argue in particular for the ethical significance of structurally diminished voluntariness, routine powerlessness in setting the terms of exchange, and incentive structures that may promote pharmaceutical interests but encourage phase 1 healthy volunteers to skirt important rules.
Flickering AGN can explain the strong circumgalactic O viobserved by COS-Halos
Authors: Oppenheimer Benjamin D , Segers Marijke , Schaye Joop , Richings Alexander J , Crain Robert A
Published: November 2017

Proximity zone fossils (PZFs) are ionization signatures around recently active galactic nuclei (AGNs) where metal species in the circumgalactic medium remain overionized after the AGNs have shut off due to their long recombination time scales. We explore cosmological zoom hydrodynamic simulations, using the EAGLE (Evolution and Assembly of GaLaxies and their Environments) model paired with a non-equilibrium ionization and cooling module including time-variable AGN radiation to model PZFs around star-forming disc galaxies in the z ∼ 0.2 Universe. Previous simulations typically underestimated the ${O{\,}\small {\rm VI}}$ content of galactic haloes, but we show that plausible PZF models increase ${O{\,}\small {\rm VI}}$ column densities by 2 − 3 × to achieve the levels observed around COS-Halos star-forming galaxies out to 150 kpc. Models with AGN bolometric luminosities ≳ 1043.6erg s− 1, duty cycle fractions ≲ 10 per cent, and AGN lifetimes ≲ 106 yr are the most promising, because their supermassive black holes grow at the cosmologically expected rate and they mostly appear as inactive AGN, consistent with COS-Halos. The central requirement is that the typical star-forming galaxy hosted an active AGN within a time-scale comparable to the recombination time of a high metal ion, which for circumgalactic ${O{\,}\small {\rm VI}}$ is ≈107 yr. ${{H{\,}\small {\rm I}}}$, by contrast, returns to equilibrium much more rapidly due to its low neutral fraction and does not show a significant PZF effect. ${O{\,}\small {\rm VI}}$ absorption features originating from PZFs appear narrow, indicating photoionization, and are often well aligned with lower metal ion species. PZFs are highly likely to affect the physical interpretation of circumgalactic high ionization metal lines if, as expected, normal galaxies host flickering AGN.
Multidisciplinary Team Learning in the Management of the Morbidly Adherent Placenta: Outcome Improvements Over Time
Authors: Shamshirsaz A.A. , Fox K.A. , Erfani H. , Belfort, et al M.A.
Published: November 2017

(Am J Obstet Gynecol. 2017 February 16)

A previous retrospective study has demonstrated that a multidisciplinary management approach can improve maternal outcomes in cases of morbidly adherent placenta (MAP), or invasive implantation of the villi into/through the myometrium. This proposed, standardized multidisciplinary approach included admission at 33 to 34 weeks of gestation with planned cesarean hysterectomy at a gestational age of 34 to 35 weeks. In the current study, the authors evaluated medical records of patients treated with this multidisciplinary management approach since January 2011, and determined whether or not there was improvement in the outcomes of singleton pregnancies with MAP when managed by a stable and increasingly experienced team.
Simulation-based Team Training for Multiprofessional Obstetric Care Teams to Improve Patient Outcome: A Multicentre, Cluster Randomized Controlled Trial
Authors: Fransen A.F. , van de Ven J. , Schuit E. , van Tetering A.A.C. , Mol B.W. , Oei S.G.
Published: November 2017

(BJOG. 2017;124:641–650)

Simulation training is considered an important component in medical education. It provides a more effective method for teaching technical skills through practice without risk to the patient. It has also been recommended for obstetric teams as a way to improve team performance and perhaps obstetric outcomes. Criteria for assessing simulation training has included participants’ perceptions of the simulation experience, assessment of knowledge and skills during and after simulation, subsequent changes in clinical practice, and ultimately improvement in patient outcomes. However, data on the effect of simulation training on patient outcomes has been limited. This study looked at the effect of a 1-day simulation-based training course for obstetric teams on the rate of patient complications over a 1-year period.
Bipolar Sealer Devices Used in Posterior Spinal Fusion for Neuromuscular Scoliosis Reduce Blood Loss and Transfusion Requirements
Authors: Hardesty Christina K. , Gordon Zachary L. , Poe-Kochert Connie , Son-Hing Jochen P. , Thompson George H.
Published: November 2017

Background:

Reducing perioperative blood loss and the need for transfusions in patients undergoing spinal surgery is especially important for those with neuromuscular disorders. These patients require extensive spino-pelvic exposure and are often medically fragile. We have used Amicar to decrease blood loss since 2001. As an effort to further reduce blood loss and transfusions, we use a bipolar sealer device (Aquamantys) as an adjunct to electrocautery. We present the results of our first 64 neuromuscular patients to show the efficacy of the device.

Methods:

Using a prospectively maintained database we reviewed the operative time, estimated perioperative blood loss, cell saver use, and intraoperative and postoperative transfusion rate in patients who underwent posterior spinal fusion for neuromuscular scoliosis. Sixty-four patients were identified who fit these criteria since the use of the bipolar sealer device was instituted.We compared these patients with a control group of the preceding 65 patients in whom this device was not used for hemostasis. All patients, including those in the study group, received Amicar (infusion of 100 mg/kg over 15 to 20 min, then 10 mg/kg/h throughout the remainder of the procedure). The surgical technique did not differ between the 2 groups.

Results:

Baseline characteristics between the 2 groups were similar except for the number of patients having an all-screw construct which was larger in the investigational group (25% vs. 8%, P=0.03). There were no significant differences in operative time or duration of hospital stay. Intraoperative blood loss was lower in the study group (741 mL) as compared with the control group (1052 mL, P=0.003). Total perioperative blood loss, however, showed no significant difference. Thirty-five (55%) patients in the study group and 50 (77%) patients in the control group required additional intraoperative or postoperative transfusions (P=0.01). The number of packed red cell units transfused per patient was 0.81 in the study group and 1.57 in the control group (P=0.001). Although the intraoperative cell saver transfusion was same, the total blood volume transfused, which includes cell saver and any other transfusions, was significantly lower in the study group, 425 mL versus 671 mL (P=0.002).

Conclusions:

Use of a bipolar sealer device in posterior spinal fusion for neuromuscular scoliosis significantly reduced intraoperative blood loss and transfusion rate when compared with a control group in this retrospective review.

Level of Evidence:

Level III—retrospective comparative study.