bluuebunny/crossref_metadata_2025 huggingface dataset:
Chaotic rotation of a spheroidal particle in simple shear flow
Authors: Rosén Tomas
Published: June 2017

The angular motion of a neutrally buoyant prolate spheroidal particle in simple shear flow has previously been found to follow two-dimensional dynamics similar to a Duffing-van der Pol oscillator as a consequence of inertia of the surrounding fluid. This behavior was however only present if the aspect ratio is large enough. When decreasing the particle aspect ratio, the particle could be found to perform period-doubled or chaotic orbits as effects of particle inertia also influence the dynamics. In this work, it is demonstrated that the onset of complex dynamics is through a Shilnikov bifurcation as the log-rolling state (particle is rotating around its symmetry axis, which is parallel to the vorticity direction) is transformed from a regular saddle node into a saddle focus when particle inertia is increased. Furthermore, it is shown that the same also applies for the two dimensional Duffing-van der Pol oscillator when including inertial terms. These results open up the possibility of developing a reduced model to mimic the influence of both fluid and particle inertia on the angular dynamics of spheroidal particles in simple shear flow, which can be used in fluid simulations with Lagrangian particles.
Scattering from isotropic plasma coated nihility sphere
Authors: Hussan M. M. , Ghaffar A. , Alkanhal Majeed A. S. , Naz M. Y. , Ur Rehman Sajjad , Khan Y.
Published: June 2017

In this study, it is observed that when an isotropic collisional plasma coating layer is produced on a nihility sphere, its back scattering efficiency becomes non-zero. Field equations, at each interface, are expanded in terms of spherical wave vector functions (SWVFs) by enforcing the extended classical wave scattering theory. Electromagnetic boundary conditions are applied at both interfaces, i.e., free space-plasma and plasma layer-nihility sphere core to obtain the scattering coefficients. The obtained scattering coefficients are used to calculate the forward scattering, back scattering, and extinction efficiencies. The obtained computational results show that an increase in collisional frequency causes a decrease in both forward and backscattered efficiencies and an increase in extinction efficiency. Furthermore, the numerical results indicate that an increase in plasma density causes an increase in both forward and backscattered efficiencies and a decrease in extinction efficiency.
Photoionization of hydrogen-like ions in dense quantum plasmas
Authors: Qi Y. Y. , Wang J. G. , Janev R. K.
Published: June 2017

The photoionization of hydrogen-like ions in n≤3 bound states, embedded in cold, dense quantum plasmas, is investigated in detail. The electron energies and wave functions for the bound and continuum states are determined by numerically solving the scaled Schrödinger equation by the fourth-order symplectic integration scheme. The monotonic behavior of the photoionization cross section for a pure Coulomb potential is dramatically changed due to the plasma screening effects described by the cosine-Debye-Hückel potential. In the region of low photoelectron energies, the photoionization cross section, besides the usual Wigner-law threshold behavior, exhibits a rich structure of shape and virtual-state resonances when the plasma screening parameter takes values around the critical screening parameter for which a bound state enters the continuum. It is observed that a shape resonance is followed by a Cooper minimum in the photoionization cross section when the principal quantum number of continuum quasi-bound state is equal to the one of the initial bound states.
Simulated evolution of three-dimensional magnetic nulls leading to generation of cylindrically-shaped current sheets
Authors: Kumar Sanjay , Bhattacharyya R.
Published: June 2017

The performed magnetohydrodynamic simulation examines the importance of magnetofluid evolution, which naturally leads to current sheets in the presence of three-dimensional (3D) magnetic nulls. The initial magnetic field is constructed by superposing a 3D force-free field on a constant axial magnetic field. The initial field supports 3D magnetic nulls having the classical spine axis and the dome-shaped fan surface and exerts non-zero Lorentz force on the magnetofluid. Importantly, the simulation identifies the development of current sheets near the 3D magnetic nulls. The morphology of the current sheets is similar to a cylindrical surface where the surface encloses the spine axis. The development is because of favorable deformation of magnetic field lines constituting the dome-shaped fan surface. The deformation of field lines is found to be caused by the flow generated by magnetic reconnections at current sheets which are located away from the cylindrically shaped current sheets.
Propagation characters of multi-Gaussian beam with large eccentric displacement in collisionless plasma: Higher order paraxial theory
Authors: Wang Ying , Yuan Chengxun , Jia Jieshu , Gao Ruilin , Hong Yunhai , Yao Jingfeng , Li Hui , Zhou Zhongxiang , Wu Jian
Published: June 2017

The multiple coherent identical Gaussian beams with symmetry distribution are abbreviated as multi-Gaussian beam, of which the propagation characters in collisionless plasma are studied with the WKB method and higher order paraxial theory. The initial beam profile presents the flat top like or hollow like distribution when the eccentric displacement is large enough. Based on the derived nonlinear propagation equations, the initial condition analyses are performed, and the impact of eccentric displacement on the free propagation effect and ponderomotive nonlinearity is thoroughly discussed. The propagation characters of dimensionless beam width parameter, spot intensity, and spatial distribution of plasma electron density are presented. Results show that the initial spot intensity is expanding outwards along the propagation and the ring structure of electron evacuation in plasmas is generated.
Evaluation of the acoustoelectric effect in the thickness direction of c-plane ZnO single crystals by Brillouin scattering
Authors: Tomita Shota , Yanagitani Takahiko , Takayanagi Shinji , Ichihashi Hayato , Shibagaki Yoshiaki , Hayashi Hiromichi , Matsukawa Mami
Published: June 2017

Longitudinal wave velocity dispersion in ZnO single crystals, owing to the acoustoelectric effect, has been investigated by Brillouin scattering. The resistivity dependence of the longitudinal wave velocity in a c-plane ZnO single crystal was theoretically estimated and experimentally investigated. Velocity dispersion owing to the acoustoelectric effect was observed in the range 0.007–10 Ωm. The observed velocity dispersion shows a similar tendency to the theoretical estimation and gives the piezoelectric stiffened and unstiffened wave velocities. However, the measured dispersion curve shows a characteristic shift from the theoretical curve. One possible reason is the carrier mobility in the sample, which could be lower than the reported value. The measurement data gave the piezoelectric stiffened and unstiffened longitudinal wave velocities, from which the electromechanical coupling coefficient k33 was determined. The value of k33 is in good agreement with reported values. This method is promising for noncontact evaluation of electromechanical coupling. In particular, it could be for evaluation of the unknown piezoelectricity in the thickness direction of semiconductive materials and film resonators.
Variation of crystal structure and optical properties of wurtzite-type oxide semiconductor alloys of β-Cu(Ga,Al)O2
Authors: Nagatani Hiraku , Mizuno Yuki , Suzuki Issei , Kita Masao , Ohashi Naoki , Omata Takahisa
Published: June 2017

Band-gap engineering of β-CuGaO2 was demonstrated by the alloying of gallium with aluminum, that is, Cu(Ga1−xAlx)O2. The ternary wurtzite β-NaFeO2-type alloys were obtained in the range 0 ≤ x ≤ 0.7, and γ-LiAlO2-type phase appeared in the range 0.7 ≤ x ≤ 1. The energy band gap of wurtzite β-CuGaO2 was controlled in the range between 1.47 and 2.09 eV. A direct band gap for x < 0.6 and indirect band gap for x ≥ 0.6 were proposed based on the structural distortion in the β-NaFeO2-type phase and density functional theory (DFT) calculation of β-CuAlO2. The DFT calculation also indicated that the γ-LiAlO2-type phases appeared in 0.7 ≤ x ≤ 1 are also indirect-gap semiconductors.
Existence and stability of alternative dust ion acoustic solitary waves in a dusty plasma consisting of nonthermal electrons having vortex-like velocity distribution
Authors: Sardar Sankirtan , Bandyopadhyay Anup , Das K. P.
Published: June 2017

The recent work of Sardar et al. [Phys. Plasmas 23, 073703 (2016)] on the existence and stability of the small amplitude dust ion acoustic solitary waves in a collisionless unmagnetized plasma consisting of warm adiabatic ions, static negatively charged dust grains, isothermal positrons, and nonthermal electrons due to Cairns et al. [Geophys. Res. Lett. 22, 2709 (1995)] has been extended by considering nonthermal electrons having a vortex-like velocity distribution due to Schamel [Plasma Phys. 13, 491 (1971); 14, 905 (1972)] instead of taking nonthermal electrons. This distribution takes care of both free and trapped electrons. A Schamel's modified Kadomtsev Petviashvili (SKP) equation describes the nonlinear behaviour of dust ion acoustic waves in this plasma system. The nonlinear behaviour of the dust ion acoustic wave is described by the same Kadomtsev Petviashvili (KP) equation of Sardar et al. [Phys. Plasmas 23, 073703 (2016)] when B = 0, where B is the coefficient of nonlinear term of the SKP equation. A combined SKP-KP equation more efficiently describes the nonlinear behaviour of dust ion acoustic waves when B → 0. The solitary wave solution of the SKP equation and the alternative solitary wave solution of the combined SKP-KP equation having profile different from both sech4 and sech2 are stable at the lowest order of the wave number. It is found that this alternative solitary wave solution of the combined SKP-KP equation and its lowest order stability analysis are exactly the same as those of the solitary wave solution of the KP equation when B → 0.
Effect of anode position on the performance characteristics of a low-power cylindrical Hall thruster
Authors: Gao Yuanyuan , Liu Hui , Hu Peng , Huang Hongyan , Yu Daren
Published: June 2017

In this paper, the design of a new cylindrical Hall thruster (CHT) is presented. Its anode is separated from the gas distributor, which is made of ceramic. The effect of the anode position on the performance characteristics of the CHT was investigated by mounting a series of anodes with different radii inside the CHT. It is found that progressively positioning the anode away from the axis along the radial direction increases the ion current and reduces the electron current. Meanwhile, the peak energy in the ion energy distribution function increases, and the shape of the ion energy distribution function noticeably narrows; the ion beam in the plume converges. It is suggested that moving the anode away from the axis may strengthen the electron confinement, thus optimizing the ionization efficiency. Additionally, the electric field near the anode appears to deflect toward the axis, which may promote the collimation of the ion beam in the plume. As a result, the overall performance of the CHT is significantly enhanced in our proposed design.
Measuring the compression velocity of a Z pinch in an axial magnetic field
Authors: Rousskikh A. G. , Zhigalin A. S. , Oreshkin V. I. , Baksht R. B.
Published: June 2017

This paper presents the results of measuring the velocity of the plasma boundary during the compression of a metallic gas-puff Z pinch in an axial magnetic field. The experiment was conducted on the IMRI-5 facility (current pulse of 450-kA amplitude with a 450-ns rise time); the initial magnetic field Bz0 was varied in the range of 0.15–0.6 T. To measure the compression velocity, B-dot probes were used successfully. The data obtained with the B-dot probes agree with the results obtained by other methods [visible imaging and determination of the pinch radius as a function of the time-varying pinch inductance L(t)]. It is shown that the plasma compression velocity is (1–1.5) × 107 cm/s at Bz0 = 0 and 0.6 × 107 cm/s at Bz0 = 0.6 T.
High light extraction efficiency into glass substrate in organic light-emitting diodes by patterning the cathode in graded superlattice with dual periodicity and dual basis
Authors: Hassan Safaa , Lowell David , Lin Yuankun
Published: June 2017

The newly discovered graded, superlattice photonic crystals with dual periodicity and dual basis present great opportunity for electromagnetic wave control in photonic devices. These graded superlattices can be holographically fabricated by eight beam interference lithography. We have computed, through electrodynamic simulation, the light extraction efficiency of planar, white organic light-emitting diodes where the Al cathode is patterned with the graded superlattice with dual basis. Two graded super-lattices with four-fold and two-fold symmetries are used to pattern the Al cathode. The decrease in power losses to surface plasmon and waveguide modes is explained by the varying plasmon path length and grating cycle, respectively, in the graded pattern. To the authors' best knowledge, the highest light extraction efficiency of 73.1% into the glass substrate in organic light-emitting diodes has been predicted through simulations.
Anticoherent subspaces
Authors: Pereira Rajesh , Paul-Paddock Connor
Published: June 2017

We extend the notion of anticoherent spin states to anticoherent subspaces. An anticoherent subspace of order t is a subspace whose unit vectors are all anticoherent states of order at least t. We use Klein’s description of algebras of polynomials which are invariant under finite subgroups of SU(2) on C2 to provide constructions of anticoherent subspaces. We discuss applications of this idea to the entanglement of n qubit symmetric states. Furthermore, we show a connection between the existence of these subspaces and the properties of the higher-rank numerical range for certain products of spin observables. We also note that these constructions give us subspaces of spin states all of whose unit vectors have Majorana representations which are spherical designs of order at least t.
Significant performance enhancement of inverted organic light-emitting diodes by using ZnIx as a hole-blocking layer
Authors: Cheng Chuan-Hui , Zhang Bi-Long , Sun Chao , Li Ruo-Xuan , Wang Yuan , Tian Wen-Ming , Zhao Chun-Yi , Jin Sheng-Ye , Liu Wei-Feng , Luo Ying-Min , Du Guo-Tong , Cong Shu-Lin
Published: June 2017

A highly efficient inverted organic light emitting diode using 1.0 nm-thick ZnIx as a hole-blocking layer is developed. We fabricate devices with the configuration ITO/ZnIx (1.0 nm)/Alq3 (50 nm)/NPB (50 nm)/MoO3 (6.0 nm)/Al (100 nm). The deposition of a ZnIx layer increases the maximum luminance by two orders of magnitude from 13.4 to 3566.1 cd/m2. In addition, the maximum current efficiency and power efficiency are increased by three orders of magnitude, and the turn-on voltage to reach 1 cd/m2 decreases from 13 to 8 V. The results suggest that the electron injection efficiency is not improved by introducing a ZnIx layer. Instead, the improved device performance originates from the strong hole-blocking ability of ZnIx. This work indicates that layered materials may lead to novel applications in optoelectronic devices.
Three-dimensional transverse vibration of microtubules
Authors: Li Si , Wang Chengyuan , Nithiarasu Perumal
Published: June 2017

A three-dimensional (3D) transverse vibration was reported based on the molecular structural mechanics model for microtubules (MTs), where the bending axis of the cross section rotates in an anticlockwise direction and the adjacent half-waves oscillate in different planes. Herein, efforts were invested to capturing the physics behind the observed phenomenon and identifying the important factors that influence the rotation angle between two adjacent half waves. A close correlation was confirmed between the rotation of the oscillation planes and the helical structures of the MTs, showing that the 3D mode is a result of the helicity found in the MTs. Subsequently, the wave length-dependence and the boundary condition effects were also investigated for the 3D transverse vibration of the MTs. In addition, the vibration frequency was found to remain the same in the presence or absence of the bending axis rotation. This infers that the unique vibration mode is merely due to the bending axis rotation of the cross section, but no significant torsion occurs for the MTs.
Note: A novel cantilever beam for low-frequency high performance piezoelectric geophone
Authors: Xin Yi , Sun Hongshuai , Guo Chao , Li Xiang , Xu Yang , Lin Tingting , Wang Shuhong , Wang Cheng
Published: June 2017

A multilayer spiral-corrugated cantilever beam was developed as an improvement for a conventional single-layer flat cantilever beam to improve the performance of a piezoelectric geophone adopting polyvinylidene fluoride film for low frequency seismic vibration measurement. The proposed structure is longer and has less stiffness compared with the conventional beam, so the piezoelectric geophone adopting the developed cantilever beam has a lower natural frequency. To confirm the validity of the design, the finite element analysis was conducted and the results showed that the natural frequency of the geophone with the multilayer spiral-corrugated cantilever beam is much lower and the corrugated structure can improve the sensitivity of the geophone.
Mayfly assemblage structure of the Pantanal Mortes–Araguaia flood plain
Authors: Juen Leandro , Brasil Leandro Schlemmer , Salles Frederico Falcão , Batista Joana Darc , Cabette Helena Soares Ramos
Published: June 2017

The diversity of lakes, rivers and streams of flood plain sustains great taxonomic and functional diversity. The Bananal flood plain is located mainly in the State of Mato Grosso, in the southern region of the Cerrado Biome and north of the Cerrado–Amazonia transition zone, two very diverse ecosystems. In the present study, to test the hypothesis that composition, richness and functional groups would differ between regions (south and north), as well as between environments (lentic and lotic), always being greater in the northern area and in lotic environments, immature Ephemeroptera individuals were collected from 12 aquatic environments, 6 streams and 6 lakes, in the northern and southern regions of the plains. Composition differed only between regions; the richness of genera and the number of functional feeding groups was higher in the northern region, and did not differ between environments. The greater diversity in the northern region may be because of its location in the ecotone of two highly diverse ecosystems, whereas the similarity between the lentic and lotic environments may be because of the homogenisation temporarily caused by floods during the flood period, increasing fluvial connectivity. Knowledge of the diversity patterns in these inhospitable regions spatially minimises knowledge gaps and provides empirical evidence of the importance of areas such as the Cerrado–Amazon transition for conservation, as shown in the present study.
Prevalence of Substance use among Middle School–Aged E-Cigarette users Compared with Cigarette Smokers, Nonusers, and Dual Users: Implications for Primary Prevention
Authors: Kristjansson Alfgeir L. , Mann Michael J. , Smith Megan L.
Published: June 2017

Background

The objective of this study was to compare the prevalence of substance use in e-cigarette (EC)-only users with combustible cigarette (CC)-only users, dual users, and nonusers in a large sample of middle school–aged adolescents.

Methods

Population-based cross-sectional school survey conducted in 15 middle schools in 3 counties in West Virginia in the United States between October and December of 2015 ( N = 6547, girls = 49.6%; response rate 84.7%).

Results

Approximately 4.3% of participants had used EC only, 4.5% had used CC only, and around 5.5% were dual users. Nonusers had the lowest prevalence of all 9 forms of substance use assessed in the study (i.e., chewing tobacco, any alcohol, drunkenness, marijuana, sniffing, prescription drugs, hallucinogens, synthetic marijuana, and bath salts), followed by EC and CC users. Dual users had the highest prevalence of 8 of 9 forms of substance use. Multinomial logistic regression models showed that EC-only users had significantly greater odds over nonusers of using 8 of 9 types of substances included in the study. Conversely, EC-only users had significantly lower odds of using 7 of 9 types of substances when compared with dual users. However, EC-only users did not differ from CC-only users in odds of use in any of the 9 substances included in this analysis.

Conclusions

Among middle school–aged adolescents, EC-only users do not differ from CC-only users in odds for other forms of substance use. Primary prevention programs should consider EC use initiation as a pathway to greater risk of other licit and illicit substances among young adolescents.
BAIAP3, a C2 domain–containing Munc13 protein, controls the fate of dense-core vesicles in neuroendocrine cells
Authors: Zhang Xingmin , Jiang Shan , Mitok Kelly A. , Li Lingjun , Attie Alan D. , Martin Thomas F.J.
Published: June 2017

Dense-core vesicle (DCV) exocytosis is a SNARE (soluble N-ethylmaleimide–sensitive fusion attachment protein receptor)-dependent anterograde trafficking pathway that requires multiple proteins for regulation. Several C2 domain–containing proteins are known to regulate Ca2+-dependent DCV exocytosis in neuroendocrine cells. In this study, we identified others by screening all (∼139) human C2 domain–containing proteins by RNA interference in neuroendocrine cells. 40 genes were identified, including several encoding proteins with known roles (CAPS [calcium-dependent activator protein for secretion 1], Munc13-2, RIM1, and SYT10) and many with unknown roles. One of the latter, BAIAP3, is a secretory cell–specific Munc13-4 paralog of unknown function. BAIAP3 knockdown caused accumulation of fusion-incompetent DCVs in BON neuroendocrine cells and lysosomal degradation (crinophagy) of insulin-containing DCVs in INS-1 β cells. BAIAP3 localized to endosomes was required for Golgi trans-Golgi network 46 (TGN46) recycling, exhibited Ca2+-stimulated interactions with TGN SNAREs, and underwent Ca2+-stimulated TGN recruitment. Thus, unlike other Munc13 proteins, BAIAP3 functions indirectly in DCV exocytosis by affecting DCV maturation through its role in DCV protein recycling. Ca2+ rises that stimulate DCV exocytosis may stimulate BAIAP3-dependent retrograde trafficking to maintain DCV protein homeostasis and DCV function.
KRS: A cut away from release in exosomes
Authors: Rabouille Catherine
Published: June 2017

Cancer cells often trigger an inflammatory process, which in some cases may be driven by the presence of lysyl-tRNA synthetase (KRS) in the medium. Kim et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201605118) now demonstrate that cleavage of the KRS by caspase-8 inside cells triggers its interaction with syntenin and its release in inflammatory exosomes.
NLRX1 dampens oxidative stress and apoptosis in tissue injury via control of mitochondrial activity
Authors: Stokman Geurt , Kors Lotte , Bakker Pieter J. , Rampanelli Elena , Claessen Nike , Teske Gwendoline J.D. , Butter Loes , van Andel Harmen , van den Bergh Weerman Marius A. , Larsen Per W.B. , Dessing Mark C. , Zuurbier Coert J. , Girardin Stephen E. , Florquin Sandrine , Leemans Jaklien C.
Published: June 2017

Mitochondrial dysfunction is the most prominent source of oxidative stress in acute and chronic kidney disease. NLRX1 is a receptor of the innate immune system that is ubiquitously expressed and localized in mitochondria. We investigated whether NLRX1 may act at the interface of metabolism and innate immunity in a model of oxidative stress. Using a chimeric mouse model for renal ischemia-reperfusion injury, we found that NLRX1 protects against mortality, mitochondrial damage, and epithelial cell apoptosis in an oxidative stress–dependent fashion. We found that NLRX1 regulates oxidative phosphorylation and cell integrity, whereas loss of NLRX1 results in increased oxygen consumption, oxidative stress, and subsequently apoptosis in epithelial cells during ischemia-reperfusion injury. In line, we found that NLRX1 expression in human kidneys decreased during acute renal ischemic injury and acute cellular rejection. Although first implicated in immune regulation, we propose that NLRX1 function extends to the control of mitochondrial activity and prevention of oxidative stress and apoptosis in tissue injury.
No fuzzy space for intracellular Na+ in healthy ventricular myocytes
Authors: Sachse Frank B. , Clark Robert , Giles Wayne R.
Published: June 2017

Sachse et al. highlight work that reveals a Na+-dependent inactivation mechanism in the Na+/K+ pump.
Brain monoamine oxidase B and A in human parkinsonian dopamine deficiency disorders
Authors: Tong Junchao , Rathitharan Gausiha , Meyer Jeffrey H , Furukawa Yoshiaki , Ang Lee-Cyn , Boileau Isabelle , Guttman Mark , Hornykiewicz Oleh , Kish Stephen J
Published: June 2017

See Jellinger (doi:10.1093/awx190) for a scientific commentary on this article. 

The enzyme monoamine oxidases (B and A subtypes, encoded by MAOB and MAOA, respectively) are drug targets in the treatment of Parkinson’s disease. Inhibitors of MAOB are used clinically in Parkinson’s disease for symptomatic purposes whereas the potential disease-modifying effect of monoamine oxidase inhibitors is debated. As astroglial cells express high levels of MAOB, the enzyme has been proposed as a brain imaging marker of astrogliosis, a cellular process possibly involved in Parkinson’s disease pathogenesis as elevation of MAOB in astrocytes might be harmful. Since brain monoamine oxidase status in Parkinson’s disease is uncertain, our objective was to measure, by quantitative immunoblotting in autopsied brain homogenates, protein levels of both monoamine oxidases in three different degenerative parkinsonian disorders: Parkinson’s disease (n = 11), multiple system atrophy (n = 11), and progressive supranuclear palsy (n = 16) and in matched controls (n = 16). We hypothesized that if MAOB is ‘substantially’ localized to astroglial cells, MAOB levels should be generally associated with standard astroglial protein measures (e.g. glial fibrillary acidic protein). MAOB levels were increased in degenerating putamen (+83%) and substantia nigra (+10%, non-significant) in multiple system atrophy; in caudate (+26%), putamen (+27%), frontal cortex (+31%) and substantia nigra (+23%) of progressive supranuclear palsy; and in frontal cortex (+33%), but not in substantia nigra of Parkinson’s disease, a region we previously reported no increase in astrocyte protein markers. Although the magnitude of MAOB increase was less than those of standard astrocytic markers, significant positive correlations were observed amongst the astrocyte proteins and MAOB. Despite suggestions that MAOA (versus MAOB) is primarily responsible for metabolism of dopamine in dopamine neurons, there was no loss of the enzyme in the parkinsonian substantia nigra; instead, increased nigral levels of a MAOA fragment and ‘turnover’ of the enzyme were observed in the conditions. Our findings provide support that MAOB might serve as a biochemical imaging marker, albeit not entirely specific, for astrocyte activation in human brain. The observation that MAOB protein concentration is generally increased in degenerating brain areas in multiple system atrophy (especially putamen) and in progressive supranuclear palsy, but not in the nigra in Parkinson’s disease, also distinguishes astrocyte behaviour in Parkinson’s disease from that in the two ‘Parkinson-plus’ conditions. The question remains whether suppression of either MAOB in astrocytes or MAOA in dopamine neurons might influence progression of the parkinsonian disorders.
Superior Prognostic Value of Cumulative Intracranial Tumor Volume Relative to Largest Intracranial Tumor Volume for Stereotactic Radiosurgery-Treated Brain Metastasis Patients
Authors: Hirshman Brian R , Wilson Bayard , Ali Mir Amaan , Proudfoot James A , Koiso Takao , Nagano Osamu , Carter Bob S , Serizawa Toru , Yamamoto Masaaki , Chen Clark C
Published: June 2017

BACKGROUND

Two intracranial tumor volume variables have been shown to prognosticate survival of stereotactic-radiosurgery-treated brain metastasis patients: the largest intracranial tumor volume (LITV) and the cumulative intracranial tumor volume (CITV).

OBJECTIVE

To determine whether the prognostic value of the Scored Index for Radiosurgery (SIR) model can be improved by replacing one of its components—LITV—with CITV.

METHODS

We compared LITV and CITV in terms of their survival prognostication using a series of multivariable models that included known components of the SIR: age, Karnofsky Performance Score, status of extracranial disease, and the number of brain metastases. Models were compared using established statistical measures, including the net reclassification improvement (NRI > 0) and integrated discrimination improvement (IDI). The analysis was performed in 2 independent cohorts, each consisting of ∼3000 patients.

RESULTS

In both cohorts, CITV was shown to be independently predictive of patient survival. Replacement of LITV with CITV in the SIR model improved the model's ability to predict 1-yr survival. In the first cohort, the CITV model showed an NRI > 0 improvement of 0.2574 (95% confidence interval [CI] 0.1890-0.3257) and IDI of 0.0088 (95% CI 0.0057-0.0119) relative to the LITV model. In the second cohort, the CITV model showed a NRI > 0 of 0.2604 (95% CI 0.1796-0.3411) and IDI of 0.0051 (95% CI 0.0029-0.0073) relative to the LITV model.

CONCLUSION

After accounting for covariates within the SIR model, CITV offers superior prognostic value relative to LITV for stereotactic radiosurgery-treated brain metastasis patients.
Predictors of Unplanned Hospitalization in Patients Receiving Outpatient Parenteral Antimicrobial Therapy Across a Large Integrated Healthcare Network
Authors: Schmidt Monica , Hearn Bevin , Gabriel Michael , Spencer Melanie D. , McCurdy Lewis
Published: June 2017

Background

Outpatient parenteral antimicrobial therapy (OPAT) prescribing has increased along with the trend toward early discharge of hospitalized patients who have infections. There is limited literature that assesses unplanned hospitalizations during OPAT. This study aims to elucidate the predictors of unplanned hospitalization in OPAT patients after discharge from acute-care facilities within Carolinas HealthCare System (CHS). Understanding these predictors may inform future interventions to improve treatment efficacy and patient outcomes.

Methods

The study cohort included hospitalized patients aged >19 years who initiated OPAT in an acute-care facility within CHS in 2014–2015. Patients who had OPAT prescribed at an ambulatory-care facility were excluded. The primary outcome was unplanned hospitalization anytime during the at-risk time from discharge through 90 days.

Results

The unplanned hospitalization rate for the cohort was 18.5%. In adjusted analysis, having OPAT delivered at a skilled nursing facility was associated with a 46% (incident risk ratio = 1.46; 95% confidence interval = 1.04–2.06) increased risk of an unplanned hospitalization compared with patients receiving OPAT at home after adjustment for demographics, comorbidities, indication, treatment duration, and antimicrobial prescribed. Infusion, dialysis, and rehabilitation centers had the lowest rates of unplanned hospitalizations.

Conclusions

These results suggest that the location of OPAT delivery is associated with unplanned hospitalizations and that older patients need additional support during OPAT.
Statin and Its Association With Delirium in the Medical ICU*
Authors: Mather Jeffrey F. , Corradi John P. , Waszynski Christine , Noyes Adam , Duan Yinghui , Grady James , Dicks Robert
Published: June 2017

Objectives:

To examine the association between statin use and the risk of delirium in hospitalized patients with an admission to the medical ICU.

Design:

Retrospective propensity-matched cohort analysis with accrual from September 1, 2012, to September 30, 2015.

Setting:

Hartford Hospital, Hartford, CT.

Patients:

An initial population of patients with an admission to a medical ICU totaling 10,216 visits were screened for delirium by means of the Confusion Assessment Method. After exclusions, a population of 6,664 was used to match statin users and nonstatin users. The propensity-matched cohort resulted in a sample of 1,475 patients receiving statin matched 1:1 with control patients not using statin.

Interventions:

None.

Measurements and Main Results:

Delirium defined as a positive Confusion Assessment Method assessment was the primary end point. The prevalence of delirium was 22.3% in the unmatched cohort and 22.8% in the propensity-matched cohort. Statin use was associated with a significant decrease in the risk of delirium (odds ratio, 0.47; 95% CI, 0.38–0.56). Considering the type of statin used, atorvastatin (0.51; 0.41–0.64), pravastatin (0.40; 0.28–0.58), and simvastatin (0.33; 0.21–0.52) were all significantly associated with a reduced frequency of delirium.

Conclusions:

The use of statins was independently associated with a reduction in the risk of delirium in hospitalized patients. When considering types of statins used, this reduction was significant in patients using atorvastatin, pravastatin, and simvastatin. Randomized trials of various statin types in hospitalized patients prone to delirium should validate their use in protection from delirium.
Single-Case Design, Analysis, and Quality Assessment for Intervention Research
Authors: Lobo Michele A. , Moeyaert Mariola , Baraldi Cunha Andrea , Babik Iryna
Published: June 2017

Background and Purpose:

The purpose of this article is to describe single-case studies and contrast them with case studies and randomized clinical trials. We highlight current research designs, analysis techniques, and quality appraisal tools relevant for single-case rehabilitation research.

Summary of Key Points:

Single-case studies can provide a viable alternative to large group studies such as randomized clinical trials. Single-case studies involve repeated measures and manipulation of an independent variable. They can be designed to have strong internal validity for assessing causal relationships between interventions and outcomes, as well as external validity for generalizability of results, particularly when the study designs incorporate replication, randomization, and multiple participants. Single-case studies should not be confused with case studies/series (ie, case reports), which are reports of clinical management of a patient or a small series of patients.

Recommendations for Clinical Practice:

When rigorously designed, single-case studies can be particularly useful experimental designs in a variety of situations, such as when research resources are limited, studied conditions have low incidences, or when examining effects of novel or expensive interventions. Readers will be directed to examples from the published literature in which these techniques have been discussed, evaluated for quality, and implemented.
A Classification System to Guide Physical Therapy Management in Huntington Disease: A Case Series
Authors: Fritz Nora E. , Busse Monica , Jones Karen , Khalil Hanan , Quinn Lori
Published: June 2017

Background and Purpose:

Individuals with Huntington disease (HD), a rare neurological disease, experience impairments in mobility and cognition throughout their disease course. The Medical Research Council framework provides a schema that can be applied to the development and evaluation of complex interventions, such as those provided by physical therapists. Treatment-based classifications, based on expert consensus and available literature, are helpful in guiding physical therapy management across the stages of HD. Such classifications also contribute to the development and further evaluation of well-defined complex interventions in this highly variable and complex neurodegenerative disease. The purpose of this case series was to illustrate the use of these classifications in the management of 2 individuals with late-stage HD.

Case Description:

Two females, 40 and 55 years of age, with late-stage HD participated in this case series. Both experienced progressive declines in ambulatory function and balance as well as falls or fear of falling. Both individuals received daily care in the home for activities of daily living.

Intervention:

Physical therapy Treatment–Based Classifications for HD guided the interventions and outcomes. Eight weeks of in-home balance training, strength training, task-specific practice of functional activities including transfers and walking tasks, and family/carer education were provided.

Outcomes:

Both individuals demonstrated improvements that met or exceeded the established minimal detectible change values for gait speed and Timed Up and Go performance. Both also demonstrated improvements on Berg Balance Scale and Physical Performance Test performance, with 1 of the 2 individuals exceeding the established minimal detectible changes for both tests. Reductions in fall risk were evident in both cases.

Discussion:

These cases provide proof-of-principle to support use of treatment-based classifications for physical therapy management in individuals with HD. Traditional classification of early-, mid-, and late-stage disease progression may not reflect patients' true capabilities; those with late-stage HD may be as responsive to interventions as those at an earlier disease stage.

Video Abstract available for additional insights from the authors (see Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A172).
Uptake of Home-Based Syphilis and Human Immunodeficiency Virus Testing Among Male Partners of Pregnant Women in Western Kenya
Authors: Mark Jennifer , Kinuthia John , Roxby Alison C. , Krakowiak Daisy , Osoti Alfred , Richardson Barbra A. , Gone Molly Ann , Asila Victor , Parikh Saloni , Farquhar Carey
Published: June 2017

Background

Few men are tested for syphilis or human immunodeficiency virus (HIV) during their partner’s pregnancy, a high-risk period for HIV and syphilis transmission. Offering home-based rapid testing of syphilis to couples during pregnancy can support prevention efforts to reduce transmission of sexually transmitted diseases and adverse pregnancy outcomes.

Methods

We assessed men’s uptake of paired (separate tests, single blood draw) point-of-care syphilis and HIV tests within a randomized controlled trial of pregnant women who received clinic or home partner HIV testing. We evaluated acceptance of paired HIV-syphilis testing during pregnancy or at 6 months postpartum, and evaluated whether addition of syphilis testing affected the uptake of HIV testing among men.

Results

Of 601 women, we were unable to meet 101 male partners, and 180 tested before syphilis tests were available. Paired syphilis and HIV testing was offered at home to 80 men during pregnancy and to 230 men postpartum. For syphilis, 93% of men agreed to test during pregnancy and 98% agreed postpartum. For paired syphilis and HIV testing, 91% of men tested for both during pregnancy and 96% tested postpartum. Before syphilis test introduction, 96% of men accepted HIV testing, compared with 95% of men who accepted HIV testing when paired testing was offered.

Conclusions

Uptake of syphilis and HIV testing was high among male partners offered couple testing at home. Introducing syphilis testing did not adversely affect HIV testing among men. Point-of-care diagnostics outside facilities can increase testing of male partners who rarely accompany women to antenatal clinics.
Elevated Central Venous to Arterial Co 2 Difference Is Not Associated With Poor Clinical Outcomes After Cardiac Surgery With Cardiopulmonary Bypass in Children
Authors: Akamatsu Takaaki , Inata Yu , Tachibana Kazuya , Hatachi Takeshi , Takeuchi Muneyuki
Published: June 2017

Objective:

To investigate whether elevated central venous to arterial Co
2 difference is associated with delayed extubation and prolonged ICU stay in children after cardiac surgery with cardiopulmonary bypass.

Design:

Retrospective review of medical records.

Setting:

PICU in a tertiary children’s hospital.

Patients:

Pediatric patients younger than 18 years old who underwent cardiac surgery with cardiopulmonary bypass between January 2014 and December 2014.

Interventions:

None.

Measurements and Main Results:

In total, 114 patients were included in this study. On ICU admission, blood samples were obtained simultaneously from an arterial line and a central venous line. There were no strong correlations between central venous to arterial Co
2 difference (median, 11.1 [8.4–13] mm Hg) and other commonly used variables for the assessment of oxygen delivery including arteriovenous oxyhemoglobin saturation difference (R
2 = 0.16) and blood lactate concentration (R
2 = 0.02). When the patients were divided into two groups, based on the Co
2 difference, the high group (difference ≥ 6 mm Hg; n = 103 [90%]) and the low group (difference < 6 mm Hg; n = 11 [10%]) showed no difference in the time to extubation (6 vs 5 hr, respectively; p = 0.80) or in the time to discharge from ICU (4 vs 5 d, respectively; p = 0.49). There was no mortality within 30 days of surgery.

Conclusions:

Elevation of central venous to arterial Co
2 difference on ICU admission in children after cardiac surgery with cardiopulmonary bypass does not appear to be associated with delayed extubation or prolonged ICU stay.
Cation effects on haemoglobin aggregation: balance of chemisorption against physisorption of ions
Authors: Parsons Drew F. , Duignan Timothy T. , Salis Andrea
Published: June 2017

A theoretical model of haemoglobin is presented to explain an anomalous cationic Hofmeister effect observed in protein aggregation. The model quantifies competing proposed mechanisms of non-electrostatic physisorption and chemisorption. Non-electrostatic physisorption is stronger for larger, more polarizable ions with a Hofmeister series Li
+
< K
+
< Cs
+
. Chemisorption at carboxylate groups is stronger for smaller kosmotropic ions, with the reverse series Li
+
> K
+
> Cs
+
. We assess aggregation using second virial coefficients calculated from theoretical protein–protein interaction energies. Taking Cs
+
to not chemisorb, comparison with experiment yields mildly repulsive cation–carboxylate binding energies of 0.48
k
B
T
for Li
+
and 3.0
k
B
T
for K
+
. Aggregation behaviour is predominantly controlled by short-range protein interactions. Overall, adsorption of the K
+
ion in the middle of the Hofmeister series is stronger than ions at either extreme since it includes contributions from both physisorption and chemisorption. This results in stronger attractive forces and greater aggregation with K
+
, leading to the non-conventional Hofmeister series K
+
> Cs
+
≈ Li
+
.
On the colour of wing scales in butterflies: iridescence and preferred orientation of single gyroid photonic crystals
Authors: Corkery Robert W. , Tyrode Eric C.
Published: June 2017

Lycaenid
butterflies from the genera
Callophrys
,
Cyanophrys
and
Thecla
have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue–green–yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in
Callophrys rubi
confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 10
4
–10
5
crystals, for concluding the preferential alignment seen along the

at the level of single scales, appears ubiquitous. By contrast,

orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the

direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the

band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures.
Purely entropic self-assembly of the bicontinuous Ia
3
d gyroid phase in equilibrium hard-pear systems
Authors: Schönhöfer Philipp W. A. , Ellison Laurence J. , Marechal Matthieu , Cleaver Douglas J. , Schröder-Turk Gerd E.
Published: June 2017

We investigate a model of hard pear-shaped particles which forms the bicontinuous Ia

d structure by entropic self-assembly, extending the previous observations of Barmes
et al.
(2003
Phys. Rev. E
68
, 021708. (
doi:10.1103/PhysRevE.68.021708
)) and Ellison
et al.
(2006
Phys. Rev. Lett.
97
, 237801. (
doi:10.1103/PhysRevLett.97.237801
)). We specifically provide the complete phase diagram of this system, with global density and particle shape as the two variable parameters, incorporating the gyroid phase as well as disordered isotropic, smectic and nematic phases. The phase diagram is obtained by two methods, one being a compression–decompression study and the other being a continuous change of the particle shape parameter at constant density. Additionally, we probe the mechanism by which interdigitating sheets of pears in these systems create surfaces with negative Gauss curvature, which is needed to form the gyroid minimal surface. This is achieved by the use of Voronoi tessellation, whereby both the shape and volume of Voronoi cells can be assessed in regard to the local Gauss curvature of the gyroid minimal surface. Through this, we show that the mechanisms prevalent in this entropy-driven system differ from those found in systems which form gyroid structures in nature (lipid bilayers) and from synthesized materials (di-block copolymers) and where the formation of the gyroid is enthalpically driven. We further argue that the gyroid phase formed in these systems is a realization of a modulated splay-bend phase in which the conventional nematic has been predicted to be destabilized at the mesoscale due to molecular-scale coupling of polar and orientational degrees of freedom.