bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical investigation of the shock compressibility of copper in the average-atom approximation
Authors: Kadatskiy M. A. , Khishchenko K. V.
Published: November 2018

Hugoniots of solid and porous samples of copper have been calculated in the framework of the average-atom approximation by three quantum-statistical models: the Thomas–Fermi, the Thomas–Fermi with quantum and exchange corrections, and the Hartree–Fock–Slater ones. The contribution of thermal motion of ions and ion–ion interaction has been taken into account by using three models: the Boltzmann ideal gas, the one-component plasma, and the charged-hard-sphere system. The theoretical investigation of the compressibility of copper in strong shock waves has been carried out for relative measurements with various standard materials: aluminum, iron, molybdenum, and lead. Calculations have been performed over a wide range of pressures from 1 to 107 GPa and compared with available data from shock-wave experiments. A new wide-range principal Hugoniot approximation for copper is proposed.
Conformer-specific photoionization and conformational stabilities of isobutanal revealed by one-photon mass-analyzed threshold ionization (MATI) spectroscopy
Authors: Lee Yu Ran , Kim Myung Hwa , Kim Hong Lae , Kwon Chan Ho
Published: November 2018

Isobutanal is an aliphatic aldehyde which has been extensively studied as an important intermediate in isomerization reactions as well as in astrochemically relevant models in the interstellar medium. Herein, we report on the conformer-specific photoionization and conformational stabilities of isobutanal utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet (VUV) pulses. The conformational population of isobutanal under different supersonic expansion conditions was explored to identify the conformers, from which their intrinsic photoionizations can be directly elucidated by measuring the VUV-MATI spectrum corresponding to each conformer. The observed MATI spectra could be analyzed through Franck–Condon simulations at the B3LYP/cc-pVTZ level for the isobutanal conformers, trans and gauche, for which the adiabatic ionization energies were precisely determined to be 78 133 ± 3 cm−1 (9.6873 ± 0.0004 eV) and 78 557 ± 3 cm−1 (9.7398 ± 0.0004 eV), respectively. Notably, only the gauche conformer undergoes a unique geometrical change upon ionization, resulting in the progression of the CHO torsional mode in the MATI spectra. Consequently, we determined the conformational stabilities of isobutanal by conformer-specific photoionization, given that the gauche is more stable than the trans by 162 ± 50 cm−1 in the neutral ground state, while the cationic gauche is less stable than the cationic trans by 262 ± 50 cm−1.
On the impossibility of solitary Rossby waves in meridionally unbounded domains
Authors: Gottwald Georg A. , Pelinovsky Dmitry E.
Published: November 2018

Evolution of weakly nonlinear and slowly varying Rossby waves in planetary atmospheres and oceans is considered within the quasi-geostrophic equation on unbounded domains. When the mean flow profile has a jump in the ambient potential vorticity, localized eigenmodes are trapped by the mean flow with a non-resonant speed of propagation. We discuss amplitude equations for these modes. Whereas the linear problem is suggestive of a two-dimensional Zakharov-Kuznetsov equation, we found that the dynamics of Rossby waves are effectively linear and confined to zonal waveguides of the mean flow. This eliminates even the ubiquitous Korteweg-de Vries equations as the underlying model for spatially localized coherent structures in these geophysical flows.
Analyses of orientational superlattice domains in epitaxial ZnTe thin films grown on graphene and mica
Authors: Mohanty Dibyajyoti , Sun Xin , Lu Zonghuan , Washington Morris , Wang Gwo-Ching , Lu Toh-Ming , Bhat Ishwara B.
Published: November 2018

ZnTe has a favorable band alignment with CdTe and is an ideal buffer between CdTe and metal contacts used in photovoltaics. Using metalorganic chemical vapor deposition, we report epitaxial growth of ZnTe thin films on 2D substrates, namely, single crystal graphene on amorphous SiO2/Si and freshly cleaved mica(001). Despite the large in-plane lattice mismatches between ZnTe and graphene (∼75%) and between ZnTe and mica(001) (∼17%), X-ray pole figure analyses show preferred epitaxial alignments with the out-of-plane orientation along [111] for ZnTe films on both substrates. For ZnTe on graphene, besides the primary in-plane orientation of [1¯10]ZnTe//[11¯]graphene, two secondary in-plane orientations rotating ±25.28° away from the primary domain are found. A geometrical superlattice area mismatch (GSAM) model is implemented to explain the existence of the primary and secondary domains in ZnTe on graphene. For ZnTe on mica(001), only one in-plane orientational domain is found experimentally with the epitaxial relationship of [1¯10]ZnTe//[100]mica (or [1¯10]ZnTe//[21¯1¯0]mica if four-index notation is used for mica). However, the prediction of domain orientation between ZnTe and mica(001) based on the GSAM model slightly deviates from that observed experimentally. Furthermore, it should be noted that multiple order twinning domains of the primary domain are observed in both ZnTe films. While coexisting with the primary domain, each of the twinning domains is still epitaxially aligned with respect to the substrate. The in-depth understanding of ZnTe's epitaxial behaviors on graphene and mica(001) provides a valuable guidance for future studies on epitaxy of 3D zinc-blende overlayers on 2D hexagonal substrates.
Adatom dynamics and the surface reconstruction of Si(110) revealed using time-resolved electron microscopy
Authors: Furnival Tom , Knez Daniel , Schmidt Eric , Leary Rowan K. , Kothleitner Gerald , Hofer Ferdinand , Bristowe Paul D. , Midgley Paul A.
Published: November 2018

Surface dynamics lie at the heart of many areas of materials and chemical science, including heterogeneous catalysis, epitaxial growth, and device fabrication. Characterizing the dynamics of surface adsorption, reactions, and diffusion at the atomic scale is crucial to understanding and controlling such processes. Here, we use aberration-corrected scanning transmission electron microscopy to analyze the diffusive behavior of Pt atoms adsorbed on the Si(110) surface and characterize the effects of the electron beam on adatom motion, including a bias introduced by the raster scan of the probe. We further observe the evolution of the Si(110) surface, revealing evidence of developing surface steps attributed to the 16 × 2 surface reconstruction. These results demonstrate a framework for studying complex atomic-scale surface dynamics using aberration-corrected electron microscopy.
Bond dissociation energy and electronic spectroscopy of Cr+(NH3) and its isotopomers
Authors: Ashraf Muhammad Affawn , Kozubal Justine , Metz Ricardo B.
Published: November 2018

The electronic spectra of Cr+(NH3), Cr+(ND3), and Cr+(15NH3) have been measured from 14 200 to 17 400 cm−1 using photodissociation spectroscopy. Transitions are predominantly observed from the 6A1 ground state, in which the Cr+ has a 3d5 electronic configuration, to the B̃ 6E (Π) state (3d44s). There is extensive vibronic structure in the spectrum due to a long progression in the Cr–N stretch and transitions to all six spin-orbit levels in the upper state. The spin-orbit splitting in the excited state is observed to be Aso′ = 39 cm−1. For the lowest spin-orbit level, the Cr–N stretching frequency in the excited state is 343 cm−1, with an anharmonicity of 4.2 cm−1. The 6E (Π) origin is predicted to lie at T0 = 14 697 cm−1. The first peak observed is due to v′ = 1, so the observed photodissociation onset is thermodynamic rather than spectroscopic, giving D0(Cr+–NH3) = 14 830 ± 100 cm−1 (177.4 ± 1.2 kJ/mol) and D0(Cr+–ND3) = 15 040 ± 30 cm−1 (179.9 ± 0.4 kJ/mol). The 6E (Π) state of Cr+(NH3) is ∼2740 cm−1 less strongly bound than the ground state, and the Cr–N bond length increases by 0.23 ± 0.03 Å upon electronic excitation. Calculations at the time-dependent density functional theory (M06) and equations of motion coupled cluster, with single and double excitations (EOM-CCSD) level fairly accurately predict the energy and vibrational frequency of the excited state. Multi-reference configuration interaction calculations show how the spin-orbit states of Cr+(NH3) evolve into those of Cr+ + NH3.
Six-dimensional quantum dynamics for the dissociative chemisorption of HCl on rigid Ag(111) on three potential energy surfaces with different density functionals
Authors: Liu Tianhui , Fu Bina , Zhang Dong H.
Published: November 2018

We carried out six-dimensional quantum dynamics calculations for the dissociative chemisorption of HCl on a rigid Ag(111) surface, employing three potential energy surfaces (PESs) which were recently constructed using the neural network approach based on extensive density functional theory calculations with Perdew-Burke-Ernzerhof, Perdew-Wang91, and revised Perdew-Burke-Ernzerhof functionals, respectively. The vibrational excitation of HCl enhances the reactivity substantially, and the dissociation is most favored for HCl molecules colliding with rotation in a plane parallel to the Ag(111) surface (helicopter alignment). The influence of rotational excitation on the dissociation probability is much more complicated, with different trends at high and at low kinetic energies. The usage of three different PESs does not change the effects of vibrational excitation, rotational excitation, and rotational-alignment qualitatively, but it does change the magnitude of dissociation probabilities quantitatively due to the different barrier heights.
Laser-produced gaseous plasmonic resonators
Authors: Colón Quiñones Roberto A. , Underwood Thomas C. , Cappelli Mark A.
Published: November 2018

We study the electromagnetic scattering properties of a gaseous plasma resonator generated by laser-induced gas breakdown. A simple analytical model is used to describe the scattering resonance of these near-ellipsoidal plasmas and its dependence on their eccentricity and intrinsic plasma properties. This dependence is investigated through Ku band transmission experiments of a waveguide with an embedded single plasma element and optical diagnostics of the laser-induced plasma. The described resonator has the potential to be used as the building block in a new class of metamaterials with fully three-dimensional structural flexibility.
Terahertz wave generation from liquid water films via laser-induced breakdown
Authors: E Yiwen , Jin Qi , Tcypkin Anton , Zhang X.-C.
Published: November 2018

Understanding the physics of terahertz (THz) wave generation from water is essential for developing liquid THz sources. This letter reports detailed experimental measurements of THz wave emission by focusing intense laser pulses onto water films. The simulation based on a ponderomotive force-induced dipole is supported by the observation of the THz intensity dependence on the laser incidence angle. This work provides fundamental insights into the THz wave generation process in water and an alternative perspective for studying laser-induced breakdown in liquids.
Hard x-ray bursts observed in association with Rayleigh-Taylor instigated current disruption in a solar-relevant lab experiment
Authors: Marshall R. S. , Flynn M. J. , Bellan P. M.
Published: November 2018

Measurements by multiple X-ray detectors show transient emission of a 1 μs pulse of non-mono-energetic ∼6 keV X-rays by a cold, dense MHD-driven plasma jet. Because the collision mean free path is much smaller than the jet dimensions, the acceleration of particles to high energy was not expected. The X-ray pulse occurs when the jet undergoes a kink instability which accelerates the jet laterally so that a fast-growing secondary Rayleigh-Taylor instability is triggered which then breaks the jet. The jet breaking is correlated in time with several other fast changing phenomena. It is proposed that despite the short collision mean free path, an inductive electric field associated with this breaking accelerates a certain subgroup of electrons to keV energies without any of these electrons undergoing collisions. It is further proposed that after being accelerated to high energy, these fast electrons are suddenly decelerated via collisions and radiate X-rays.
Communication: Inside the water wheel: Intrinsic differences between hydrated tetraphenylphosphonium and tetraphenylborate ions
Authors: Leśniewski Mateusz , Śmiechowski Maciej
Published: November 2018

Tetraphenylphosphonium tetraphenylborate (TPTB) is a common reference electrolyte in physical chemistry of solutions allowing for a convenient partitioning of thermodynamic properties into single-ion contributions. Here, we compute on the basis of ab initio molecular dynamics simulations the infrared (IR) spectra for hydrated constituent ions of the TPTB assumption. Using spectral decomposition techniques, we extract important information pertaining to the state of the hydration water from the IR spectra. Within their physical radii, the ions manage to capture about a dozen H2O molecules, several of which penetrate deep into the grooves between the tetrahedrally oriented “sails” of the rotating ions. In accordance with previous IR and Raman experiments, we find a considerable blue shift of the νOH stretching band of liquid water by 240 cm−1 for TB, due to the extensive O–H⋯π hydrogen bonding, which is much weaker for TP. On the other hand, both ions show a second prominent band in the νOH vibration range, only mildly blue shifted with respect to bulk water and attributable to the general distortion of the hydrogen bond network of the neighboring solvent. Finally, spatially resolved IR spectra allow us to pinpoint the exact location around the solutes, from which different IR resonances of the solvent originate.
A particle-conserved weighted-average oscillator model for trapped particles in long-time nonlinear Landau damping
Authors: Hou Y. W. , Yu M. Y. , Zhu P. , Ma Z. W. , Chen M. X.
Published: November 2018

A normalized weighting function model for the average period of particles trapped in the potential wells of waves undergoing nonlinear Landau damping is considered. The model preserves the conservation properties of the trapped particles and relates them to the evolution of the wave envelope. It is valid when there are more shallowly trapped particles than deeply trapped particles, such as in long-time nonlinear Landau damping, as well as stabilities due to trapped particles at long times. The model is also useful for estimating the validity of the often invoked assumption that most trapped particles in nonlinear waves are deeply trapped.
Humans control complex objects by guiding them toward stability
Authors: Miller Johanna L.
Published: November 2018

Concepts from dynamical systems help to elucidate the subtle physics of how we move.
High-resolution speckle imaging
Authors: Howell Steve B. , Horch Elliott P.
Published: November 2018

Mathematics and technology combine to make a virtue of the graininess imposed on astrophysical images by atmospheric turbulence.
A bet-hedging strategy for denitrifying bacteria curtails their release of N
2
O
Authors: Lycus Pawel , Soriano-Laguna Manuel Jesús , Kjos Morten , Richardson David John , Gates Andrew James , Milligan Daniel Aleksanteri , Frostegård Åsa , Bergaust Linda , Bakken Lars Reier
Published: November 2018

Significance

Denitrifying microorganisms reduce nitrate to N
2
via nitrite, NO, and N
2
O under hypoxic/anoxic conditions. Since these organisms are the main sources and sinks for N
2
O in the environment, their regulatory biology controls the emission of this potent greenhouse gas. We demonstrate bet hedging in
Paracoccus denitrificans
when facing hypoxia: a minority of the cells synthesize NIR + NOR, the N
2
O source, while all synthesize NOS, the N
2
O sink, hence the population becomes a strong net sink for N
2
O. Bet hedging is prominent below 20 °C and data indicate that it is widespread in soil organisms. This suggests a prominent role of bet hedging in controlling N
2
O emissions that can now be tested for in other strains and in natural environments.
Marginal protein stability drives subcellular proteome isoelectric point
Authors: Loell Kaiser , Nanda Vikas
Published: November 2018

Significance

The rules of protein design are often derived from analyzing the properties of natural proteins. However, unlike designed proteins, natural proteins are the product of long evolutionary histories, confounding efforts to identify which properties are directly related to function versus those that are a by-product of the evolutionary process. We critically examine the observation that the isoelectric point—the pH at which proteins have no net charge—correlates with the pH of the subcellular environment occupied by that protein. This correlation is not due to adaptive selection, but is a by-product of neutral evolution. This insight can be used to understand the evolution of proteins at a range of pH and design molecules for such environments.
Oncogenic role of SFRP2 in p53-mutant osteosarcoma development via autocrine and paracrine mechanism
Authors: Kim Huensuk , Yoo Seungyeul , Zhou Ruoji , Xu An , Bernitz Jeffrey M. , Yuan Ye , Gomes Andreia M. , Daniel Michael G. , Su Jie , Demicco Elizabeth G. , Zhu Jun , Moore Kateri A. , Lee Dung-Fang , Lemischka Ihor R. , Schaniel Christoph
Published: November 2018

Significance

Li–Fraumeni syndrome is a rare disorder caused by germline
TP53
mutations, predisposing patients to early-onset cancers, including osteosarcoma (OS). Here we demonstrate that strong expression of SFRP2, a reported WNT antagonist, in OS patient samples correlates with poor survival and that SFRP2 overexpression suppresses normal osteoblast differentiation, promotes OS features, and facilitates angiogenesis via autocrine and paracrine mechanisms in an induced pluripotent stem cell disease model. We show that these SFRP2-mediated phenotypes are canonical WNT/β-catenin independent and are mediated through induction of oncogenes such as FOXM1 and CYR61. We further demonstrate that inhibition of SFRP2, FOXM1, or CYR61 represses tumorigenesis. Our data suggest that inhibition of SFRP2 should be explored clinically as a strategy for treatment patients with p53 mutation-associated OS.
Catalytic enzymes are active matter
Authors: Jee Ah-Young , Cho Yoon-Kyoung , Granick Steve , Tlusty Tsvi
Published: November 2018

Significance

Catalysis and mobility of reactants in fluid are normally thought to be decoupled. Violating this classical paradigm, this paper presents the catalyst laws of motion. Comparing experimental data to the theory presented here, we conclude that part of the free energy released by chemical reaction is channeled into driving catalysts to execute wormlike trajectories by piconewton forces performing work of a fewkBTagainst fluid viscosity, where the rotational diffusion rate dictates the trajectory persistence length. This active motion agitates the fluid medium and produces antichemotaxis, the migration of catalyst down the gradient of the reactant concentration. Alternative explanations of enhanced catalyst mobility are examined critically.
Fabrication and characterisation of functionally graded Ni-P coatings with improved wear and corrosion resistance
Authors: Hadipour Ali , Rahsepar Mansour , Hayatdavoudi Hadis
Published: November 2018

In this study, the functionally graded Ni–P coatings with low phosphorus top most layers were deposited on the copper substrates by the electroless plating process. The surface morphology and cross-section observations were made by using scanning electron microscopy and optical microscopy. The results showed that electroless deposition of the Ni–P coatings with gradual change of phosphorus content led to a crack-free compact nodular morphology. Also, by using the graded Ni–P coatings, the wear and corrosion resistance were improved. The multilayer coating with the sequence of Ni-high P/Ni-medium P/Ni-low P layers from the substrate to the top surface exhibited the best wear and corrosion resistance.
Differential GABA concentration gradients are present in the edible parts of greenhouse melon (Cucumis melo L.) during all four seasonal croppings
Authors: Toyoizumi Tomoyasu , Ohba Seiji , Fujii Kyo-suke , Ikegaya Atsushi , Matsuura Hideyuki , Nakajima Teruko
Published: November 2018

Food-derived gamma-aminobutyric acid (GABA) exhibits health-promoting benefits, and melon contain high GABA concentrations. Greenhouse melons (Cucumis melo L. “Earl’s Favorite”) cultivated in Japan have identical or more edible parts than cultivars in other countries, however GABA distribution and the effects of seasonal variations are unclear. Thus, the present study aimed to evaluate GABA concentration gradients in four seasonal melons and how glutamic acid (Glu) influences the establishment of these gradients. GABA concentration was significantly lower near the exocarp than in the peduncle, equator, and remnant style regions in most seasons. Glu and GABA concentrations showed similar trends and were significantly correlated near the remnant style. No significant differences in GABA and Glu concentration were detected at concyclic sites across horizontal sections. These data indicate that GABA and Glu concentration differs substantially along a vertical melon section, but less so along a horizontal section, among sampling regions, sites, and cropping season.
Biochemical and thermodynamic analyses of energy conversion in extremophiles
Authors: Wakai Satoshi
Published: November 2018

A variety of extreme environments, characterized by extreme values of various physicochemical parameters (temperature, pressure, salinity, pH, and so on), are found on Earth. Organisms that favorably live in such extreme environments are called extremophiles. All living organisms, including extremophiles, must acquire energy to maintain cellular homeostasis, including extremophiles. For energy conversion in harsh environments, thermodynamically useful reactions and stable biomolecules are essential. In this review, I briefly summarize recent studies of extreme environments and extremophiles living in these environments and describe energy conversion processes in various extremophiles based on my previous research. Furthermore, I discuss the correlation between the biological system of electrotrophy, a third biological energy acquisition system, and the mechanism underlying microbiologically influenced corrosion. These insights into energy conversion in extremophiles may improve our understanding of the “limits of life”.

Abbreviations: PPi: pyrophosphate; PPase: pyrophosphatase; ITC: isothermal titration microcalorimetry; SVNTase: Shewanella violacea 5ʹ-nucleotidase; SANTase: Shewanella amazonensis 5ʹ-nucleotidase
Training intensity relative to ventilatory thresholds determines cardiorespiratory fitness improvements in sedentary adults with obesity
Authors: Guio de Prada Valle , Ortega Juan Fernando , Ramirez‐Jimenez Miguel , Morales‐Palomo Felix , Pallares Jesús G. , Mora‐Rodriguez Ricardo
Published: November 2018

The aim of the present study was to study if training intensity relative to ventilatory thresholds (VTs) determines the improvements in cardiorespiratory fitness (CRF) in middle‐aged sedentary individuals with obesity. Before and after 16‐weeks of HIIT (43‐min alternating bouts at 70/90% of HRMAX), oxygen consumption (O2) and heart rate (HR) at ventilatory threshold 1 (O2VT1, HRVT1), ventilatory threshold 2 (O2VT2, HRVT2) and at maximal effort (O2MAX, HRMAX) were assessed during a graded cycle‐ergometer exercise test. Retrospectively, participants were divided into two groups based on whether training intensities were under (UNDER; n = 39) or over (OVER; n = 37) VT1 and VT2. At baseline, age, body composition, O2VT1, O2VT2, and HRMAX were similar in both groups. However, O2MAX was higher in OVER (P = 0.033), whereas HRVT1 and HRVT2 were higher in UNDER (P < 0.05). O2MAX (9.0%) and HRMAX (2.2%) improved similarly in both groups. O2VT1 and O2VT2 improved with training in both groups (P < 0.001) but the improvement was larger in OVER versus UNDER in O2VT1 (P = 0.013) and tended to be higher in O2VT2 (P = 0.068). HRVT1 increased only in OVER (P < 0.001), whereas HRVT2 did not change in any group (P = 0.248). A 16‐week programme of HIIT improves O2MAX similarly in individuals training at intensities over or under their VTs. However, individuals training over their VTs showed a larger improvements in O2VT1 expanding exercise workloads fuelled by oxidative metabolism.
Microbiome–microglia connections via the gut–brain axis
Authors: Abdel-Haq Reem , Schlachetzki Johannes C.M. , Glass Christopher K. , Mazmanian Sarkis K.
Published: November 2018

Microglia, the resident immune cells in the brain, are essential for modulating neurogenesis, influencing synaptic remodeling, and regulating neuroinflammation by surveying the brain microenvironment. Microglial dysfunction has been implicated in the onset and progression of several neurodevelopmental and neurodegenerative diseases; however, the multitude of factors and signals influencing microglial activity have not been fully elucidated. Microglia not only respond to local signals within the brain but also receive input from the periphery, including the gastrointestinal (GI) tract. Recent preclinical findings suggest that the gut microbiome plays a pivotal role in regulating microglial maturation and function, and altered microbial community composition has been reported in neurological disorders with known microglial involvement in humans. Collectively, these findings suggest that bidirectional crosstalk between the gut and the brain may influence disease pathogenesis. Herein, we discuss recent studies showing a role for the gut microbiome in modulating microglial development and function in homeostatic and disease conditions and highlight possible future research to develop novel microbial treatments for disorders of the brain.
The Picard group of the moduli of smooth complete intersections of two quadrics
Authors: Asgarli Shamil , Inchiostro Giovanni
Published: November 2018

We study the moduli space of smooth complete intersections of two quadrics in

P

n

\mathbb {P}^n

by relating it to the geometry of the singular members of the corresponding pencils. By giving an alternative presentation for the moduli space of complete intersections, we compute the Picard group for all

n
≥
3

n\geq 3

.
Frobenius stratification of moduli spaces of rank 3 vector bundles in positive characteristic 3, I
Authors: Li Lingguang
Published: November 2018

Let

X
X

be a smooth projective curve of genus

g
≥
2

g\geq 2

over an algebraically closed field

k
k

of characteristic

p
>
0

p>0

, and let

F
X

:
X
→
X

F_X:X\rightarrow X

be the absolute Frobenius morphism. Let

M

X
s

(
r
,
d
)

\mathfrak {M}^s_X(r,d)

be the moduli space of stable vector bundles of rank

r
r

and degree

d
d

on

X
X

. We study the Frobenius stratification of

M

X
s

(
3
,
0
)

\mathfrak {M}^s_X(3,0)

in terms of Harder–Narasimhan polygons of Frobenius pull backs of stable vector bundles and obtain the irreducibility and dimension of each nonempty Frobenius stratum in the case in which

(
p
,
g
)
=
(
3
,
2
)

(p,g)=(3,2)

.
Deriving an Adolescent Executive Behavior Screener from the Behavior Assessment System for Children—2
Authors: Wong Ryan E , Sakaluk John K , Garcia-Barrera Mauricio A
Published: November 2018

Objective

Typical executive functioning (EF) measurements do not reflect the complexity of daily life. We derived an executive behavior screener from the BASC-2-PRS-A using a previously derived four-component model of EF and provided support for the use of the screener in adolescent populations.

Methods

A total of 2,722 census-matched American adolescents were sampled. We assigned 25 items a priori to four executive factors (problem solving, attentional control, behavioral control, and emotional control) and evaluated via confirmatory factor analysis, invariance testing and differential item functioning (DIF) models.

Results

We found acceptable-to-good reliability and that the four-factor model had the best fit. We showed DIF for age and socioeconomic status (SES). While groups were invariant based on sex, latent mean comparisons showed significant differences.

Conclusions

Construct validity of the adolescent four-factor model as measured through the screener was supported. Females demonstrated fewer executive behavior problems. Standardized norms are available and split by age and sex. SES may influence the interpretation of T-scores. Continued exploration and development of the screener is suggested.
Membrane cholesterol and substrate stiffness co-ordinate to induce the remodelling of the cytoskeleton and the alteration in the biomechanics of vascular smooth muscle cells
Authors: Sanyour Hanna J , Li Na , Rickel Alex P , Childs Josh D , Kinser Courtney N , Hong Zhongkui
Published: November 2018

Aims

Cholesterol not only deposits in foam cells at the atherosclerotic plaque, but also plays an important role as a regulator of cell migration in atherogenesis. In addition, the progression of atherosclerosis leads to arterial wall stiffening, and thus altering the micromechanical environment of vascular smooth muscle cells (VSMCs) in vivo. Our studies aim to test the hypothesis that membrane cholesterol and substrate stiffness co-ordinate to regulate VSMCs biomechanics, and thus potentially regulate VSMCs migration and atherosclerotic plaque formation.

Methods and results

Methyl-β-cyclodextrin was used to manipulate membrane cholesterol content in VSMCs isolated from the descending thoracic aorta of male Sprague-Dawley rats and cultured on Type I collagen-coated polyacrylamide gel substrates with varying stiffness. Atomic force microscopy (AFM) was used to determine VSMCs stiffness and integrin-fibronectin (FN) adhesion. The alignment of submembranous actin filaments was visualized with AFM and confocal microscopy. The constriction force of rat aorta was measured ex vivo using a multi-wire myograph system. Our results demonstrated that cholesterol-depletion and substrate-softening induced a significant decrease in VSMCs stiffness and adhesion to FN, as well as cytoskeletal disorganization. In addition, the contractile force of rat aorta was reduced upon cholesterol-depletion. Cholesterol-enrichment resulted in an increase in stiffness, adhesion to FN, cytoskeletal organization of VSMCs compared with the cholesterol-depleted cells, and enhanced contractile force of rat aortas compared with the cholesterol-depleted vessel rings.

Conclusion

Cell membrane cholesterol and substrate stiffness synergistically affect VSMCs elastic modulus (E-modulus) by regulating the organization of the actin cytoskeleton. Except for the 3.5 kPa gel substrate, cholesterol-depletion decreased VSMCs-FN adhesion force, adhesion loading rate, cytoskeletal orientation, and E-modulus compared with the control VSMCs. Conversely, cholesterol-enrichment significantly increased cytoskeleton orientation, stiffness, and VSMCs-FN cell adhesion force compared with both control and cholesterol-depleted VSMCs on a soft substrate.
Non-dispensing pharmacists’ actions and solutions of drug therapy problems among elderly polypharmacy patients in primary care
Authors: Hazen Ankie C M , Zwart Dorien L M , Poldervaart Judith M , de Gier Johan J , de Wit Niek J , de Bont Antoinette A , Bouvy Marcel L
Published: November 2018

Objective

To evaluate the process of clinical medication review for elderly patients with polypharmacy performed by non-dispensing pharmacists embedded in general practice. The aim was to identify the number and type of drug therapy problems and to assess how and to what extent drug therapy problems were actually solved.

Method

An observational cross-sectional study, conducted in nine general practices in the Netherlands between June 2014 and June 2015. On three pre-set dates, the non-dispensing pharmacists completed an online data form about the last 10 patients who completed all stages of clinical medication review. Outcomes were the type and number of drug therapy problems, the extent to which recommendations were implemented and the percentage of drug therapy problems that were eventually solved. Interventions were divided as either preventive (aimed at following prophylactic guidelines) or corrective (aimed at active patient problems).

Results

In total, 1292 drug therapy problems were identified among 270 patients, with a median of 5 (interquartile range 3) drug therapy problems per patient, mainly related to overtreatment (24%) and undertreatment (21%). The non-dispensing pharmacists most frequently recommended to stop medication (32%). Overall, 83% of the proposed recommendations were implemented; 57% were preventive, and 35% were corrective interventions (8% could not be assessed). Almost two-third (64%) of the corrective interventions actually solved the drug therapy problem.

Conclusion

Non-dispensing pharmacists integrated in general practice identified a large number of drug therapy problems and successfully implemented a proportionally high number of recommendations that solved the majority of drug therapy problems.
Age-Related Alterations in Gait Function in Freely Moving Male C57BL/6 Mice: Translational Relevance of Decreased Cadence and Increased Gait Variability
Authors: Tarantini Stefano , Yabluchanskiy Andriy , Fülöp Gábor A , Kiss Tamas , Perz Aleksandra , O’Connor Daniel , Johnson Emily , Sorond Farzaneh , Ungvari Zoltan I , Csiszar Anna
Published: November 2018

Age-related gait dysfunction and balance disorders are a major cause of falls and injury in the elderly population. Epidemiological studies have shown that disturbances in gait coordination which manifest with age are associated with increased morbidity and mortality, impaired cognitive capacity, as well as reduced level of function and loss of independence. In geroscience, mice are the most frequently used model system to test efficiency of antiaging interventions. Despite the clinical importance of age-related gait abnormalities in older adults, the impact of aging on mouse gait coordination is not well documented in the literature. To characterize the effect of aging on mouse gait, we assessed gait function in young (3-month-old) and aged (24-month-old) freely moving C57BL/6 mice using the semiautomated, highly sensitive CatWalk XT system for quantitative assessment of footfall and motor performance. We found that aged mice exhibited significantly decreased cadence and increased stride time variability. Aging also tended to alter footfall patterns. In aged mice, speed, swing speed, stride length, duty cycle, base of support, terminal dual stance, the regularity index, and the gait symmetry index were unaltered. Thus, aging is associated with characteristic alterations in gait function in C57BL/6 mice, which could potentially be assessed as clinically relevant endpoints in geroscience studies testing the effects of antiaging interventions.
Mean and variance of greenness and pregnancy outcomes in Tel Aviv during 2000–14: longitudinal and cross-sectional approaches
Authors: Agay-Shay Keren , Michael Yaron , Basagaña Xavier , Martínez-Solanas Èrica , Broday David , Lensky Itamar M , Rudolf Mary , Rubin Lisa , Kent Rafi , Levy Nadav , Haklai Ziona , Grotto Itamar
Published: November 2018

Background

Natural environments may have beneficial impacts on pregnancy outcomes. However, longitudinal evidence is limited and the associations with variance in surrounding greenness is unknown. Our objective was to evaluate these associations among 73 221 live births in Tel Aviv, Israel.

Methods

Longitudinal exposure to mean of greenness during pregnancy and trimesters were calculated using satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) Normalised Difference Vegetation Index (NDVI) data. In addition, exposure to mean and variation of NDVI from high-resolution satellite and percentage of tree cover [Vegetation Continuous Fields (VCF)] at 300-m buffer were evaluated in a cross-sectional approach. Generalized linear models were used to estimate the crude and adjusted associations. We explore the possible mediating role of ambient exposures and distance to ‘outdoor gyms’ located in parks.

Results

Crude beneficial associations between exposure to higher mean NDVI during pregnancy and pregnancy outcomes were observed [for birthweight, 3rd/1st tertile exposure increased the mean by 25.5 g, 95% confidence intervals (CIs): 15.4, 35.5] and decreased the odds of low birthweight, small for gestational age, preterm deliveries (PTD) and very PTD. Adjustment for individual and neighbourhood-level markers of socio-economic status (SES) attenuated all the associations. Strongest associations were observed during the first and second trimesters. Cross-sectional associations for mean greenness were similar with narrower CIs, and associations with NDVI were stronger than with tree cover and stronger for mean compared with variance of greenness. Associations were consistent for term births, different buffer sizes and for further adjustment to maternal education. Stronger associations were observed for lowest SES. Distance to ‘outdoor gyms’ and variance of greenness had the largest estimates of mediation.

Conclusion

This study adds to the limited information on when exposure to greenness is most beneficial, on the association with variance of greenness and the possible pathways. These observations require confirmation in other populations.
Comparative Efficacy of Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Malaria in Ugandan Children
Authors: Yeka Adoke , Wallender Erika , Mulebeke Ronald , Kibuuka Afizi , Kigozi Ruth , Bosco Agaba , Kyambadde Paul , Opigo Jimmy , Kalyesubula Simeon , Senzoga Joseph , Vinden Joanna , Conrad Melissa , Rosenthal Philip J
Published: November 2018

Background

In Uganda, artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DHA-PQ) showed excellent treatment efficacy for uncomplicated malaria in prior trials. Because the frequency of resistance to artemisinins and piperaquine is increasing in Southeast Asia and the prevalence of Plasmodium falciparum polymorphisms associated with resistance has changed, we reassessed treatment efficacies at 3 sites in Uganda.

Methods

For this randomized, single-blinded clinical trial, children aged 6–59 months with uncomplicated falciparum malaria were assigned treatment with AL or DHA-PQ and followed for 42 days. Primary end points were risks of recurrent parasitemia, either unadjusted or adjusted to distinguish recrudescence from new infection. We assessed selection by study regimens of relevant P. falciparum genetic polymorphisms associated with drug resistance.

Results

Of 599 patients enrolled, 578 completed follow-up. There were no early treatment failures. The risk of recurrent parasitemia was lower with DHA-PQ as compared to AL at all 3 sites at 42 days (26.0% vs 47.0%; P < .001). Recrudescent infections were uncommon in both the DHA-PQ and AL arms (1.1% and 2.2%, respectively; P = .25). Neither regimen selected for pfcrt or pfmdr1 polymorphisms associated with drug resistance.

Conclusions

AL and DHA-PQ remain effective for the treatment of malaria in Uganda. Neither regimen selected for genetic polymorphisms associated with drug resistance.

Clinical Trials Registration

ISRCTN15793046.
Modeling Zika Virus-Associated Birth Defects in Nonhuman Primates
Authors: Mohr Emma L
Published: November 2018

In utero infection with Zika virus (ZIKV) during pregnancy can lead to the development of birth defects and postnatal deficits. A nonhuman primate (NHP) model of congenital ZIKV infection can help fill the gaps in knowledge where tissue studies are required to define viral pathogenesis and identify targets for therapeutic intervention. This model system has already identified critical features of ZIKV pathogenesis in congenital infection. Before translating these NHP studies to human clinical trials, we must understand the similarities and differences between human and NHP fetal immune system development, neural development, and infant assessment tools. Because of the overall similarity between fetal and infant development in humans and NHPs, this NHP model can complement human clinical trials by defining immune correlates of protection and evaluating therapeutic interventions.
What is the Responsibility of Australian Medical Professionals Whose Patients Travel Abroad for Assisted Reproduction?
Authors: Millbank Jenni
Published: November 2018

Australian medical professionals whose patients undertake assisted reproductive treatment abroad face a conflict: to try to provide optimal and on-going care for their patient at the same time as ensuring compliance with Australian legal, ethical, and professional rules which proscribe as unsafe or unethical key aspects of such treatment.

A major suggestion from literature on medical travel is that risks to the patient can be mitigated through the involvement of the local professional. However, the force of legal regulation and ethical guidance in Australia strenuously directs clinicians away from involvement in overseas reproductive treatment.

This article reports on 37 interviews with Australians travelling abroad for surrogacy, egg donation, and embryo donation, reflecting on patients’ experiences with Australian medical professionals both before and after they travelled. Patient reports demonstrate a fragmented and bewildering medical landscape in Australia, in which the ability to access domestic care and expertise varied markedly depending upon the kind of treatment patients were seeking abroad, and the mode of practice of the Australian doctor. Doctors practicing within licensed IVF clinics were notably more constrained than those outside such a setting. Patients seeking egg donation were offered information and received a wide range of diagnostic and preparatory treatments, while those seeking surrogacy were shunned, chided and offered limited (and sometimes covert) assistance.

While recent changes to national ethical guidance improve clarity on information giving, the ethical and legal propriety of Australian medical professionals providing diagnostic or preparatory treatment for cross border reproduction remains uncertain.
Adjustment of the multi-biomarker disease activity score to account for age, sex and adiposity in patients with rheumatoid arthritis
Authors: Curtis Jeffrey R , Flake Darl D , Weinblatt Michael E , Shadick Nancy A , Østergaard Mikkel , Hetland Merete Lund , Brahe Cecilie Heegaard , Hwang Yong Gil , Furst Daniel E , Strand Vibeke , Etzel Carol J , Pappas Dimitrios A , Wang Xingbin , Hwang Ching Chang , Sasso Eric H , Gutin Alexander , Hitraya Elena , Lanchbury Jerry S
Published: November 2018

Objective

To develop and evaluate an adjusted score for the multi-biomarker disease activity (MBDA) test to account for the effects of age, sex and adiposity in patients with RA.

Methods

Two models were developed to adjust MBDA score for age, sex and adiposity, using either serum leptin concentration or BMI as proxies for adiposity. Two cohorts were studied. A cohort of 325 781 RA patients who had undergone commercial MBDA testing and had data for age, sex and serum leptin concentration was used for both models. A cohort of 1411 patients from five studies/registries with BMI data was used only for the BMI-adjusted MBDA score. Univariate and multivariate linear regression analyses evaluated the adjusted MBDA scores and conventional clinical measures as predictors of radiographic progression, assessed in terms of modified total Sharp score (ΔmTSS).

Results

Two models were developed, based on findings that MBDA score was higher in females than males and increased with age, leptin concentration and BMI. In pairwise regression analyses, the leptin-adjusted (P = 0.00066) and BMI-adjusted (P = 0.0027) MBDA scores were significant independent predictors of ΔmTSS after adjusting for DAS28-CRP, whereas DAS28-CRP was not, after adjusting for leptin-adjusted (P = 0.74) or BMI-adjusted (P = 0.87) MBDA score. Moreover, the leptin-adjusted MBDA score was a significant predictor of ΔmTSS after adjusting for the BMI-adjusted MBDA score (P = 0.025) or the original MBDA score (0.027), whereas the opposite was not true.

Conclusion

Leptin-adjusted MBDA score significantly adds information to DAS28-CRP and the original MBDA score in predicting radiographic progression. It may offer improved clinical utility for personalized management of RA.
Implementation of a Central Line Maintenance Bundle for Dislodgement and Infection Prevention in the NICU
Authors: Short Kira L.
Published: November 2018

Background:

Infants in the newborn intensive care unit (NICU) often receive medications or nutritional support for extended periods. Due to the fragility of veins, central lines are often used. Adverse outcomes from central lines such as infections and line dislodgements, where the line terminates in a peripheral vessel rather than centrally, can drastically increase infant morbidity and mortality. Although evidence exists addressing the specialized needs of premature or smaller infants, there is far less evidence regarding infants that are larger, more physiologically complex, and have longer stays.

Purpose:

Using evidence-based practice strategies, we examined the literature for central line maintenance practices specific to the NICU population and created a care maintenance bundle to reduce infection and line dislodgement rates. Furthermore, we examined implementation of this bundle.

Methods/Search Strategy:

A systematic search of PubMed, Cochrane Library, and CINAHL provided evidence for a practice change for central line maintenance for our nontunneled central lines. During project implementation, infection and dislodgement rates for both tunneled and nontunneled lines were examined in order have a control and intervention group.

Findings/Results:

Prior to central line maintenance bundle implementation, there were 19 total incidences of central line dislodgements and 5 central line infections (14 dislodgements and 4 infections were from nontunneled lines, 5 dislodgements and 1 infection from a tunneled line). Postintervention there were 1 total dislodgement and 4 central line infections (the dislodgement was from a nontunneled line and all infections were from tunneled lines).

Implications for Practice:

Although research has shown frequent, scheduled dressing changes using the chlorhexidine patch decreases infection rates, the risk of dislodgement and skin breakdown for NICU infants outweighs the potential benefit of decreased infection.

Implications for Research:

Further research is needed to determine whether this central line maintenance bundle would be beneficial for tunneled central lines.
Clearing Away Past Wreckage
Authors: Williams Lindsay , Pavlish Carol , Maliski Sally , Washington Donna
Published: November 2018

Women Veterans are the largest veteran population yet have significant mental health disparities, greater than both civilian women and veteran men. This article used constructivist grounded theory methods to explore the experiences of women Veterans that led to mental health outpatient service use. Twelve women Veterans revealed meaningful stories on their experiences of trauma and their use of mental health services. A broader grounded theory process model emerged, linking the categories of Trauma, Transitions, Identity, and Structure. This research provides key insight into how women Veterans make health care–related choices and process traumatic events such as military sexual trauma.