bluuebunny/crossref_metadata_2025 huggingface dataset:
High-resolution simulations of unstable cylindrical gravity currents undergoing wandering and splitting motions in a rotating system
Authors: Dai Albert , Wu Ching-Sen
Published: February 2018

High-resolution simulations of unstable cylindrical gravity currents when wandering and splitting motions occur in a rotating system are reported. In this study, our attention is focused on the situation of unstable rotating cylindrical gravity currents when the ratio of Coriolis to inertia forces is larger, namely, 0.5 ≤ C ≤ 2.0, in comparison to the stable ones when C ≤ 0.3 as investigated previously by the authors. The simulations reproduce the major features of the unstable rotating cylindrical gravity currents observed in the laboratory, i.e., vortex-wandering or vortex-splitting following the contraction-relaxation motion, and good agreement is found when compared with the experimental results on the outrush radius of the advancing front and on the number of bulges. Furthermore, the simulations provide energy budget information which could not be attained in the laboratory. After the heavy fluid is released, the heavy fluid collapses and a contraction-relaxation motion is at work for approximately 2−3 revolutions of the system. During the contraction-relaxation motion of the heavy fluid, the unstable rotating cylindrical gravity currents behave similar to the stable ones. Towards the end of the contraction-relaxation motion, the dissipation rate in the system reaches a local minimum and a quasi-geostrophic equilibrium state is reached. After the quasi-geostrophic equilibrium state, vortex-wandering or vortex-splitting may occur depending on the ratio of Coriolis to inertia forces. The vortex-splitting process begins with non-axisymmetric bulges and, as the bulges grow, the kinetic energy increases at the expense of decreasing potential energy in the system. The completion of vortex-splitting is accompanied by a local maximum of dissipation rate and a local maximum of kinetic energy in the system. A striking feature of the unstable rotating cylindrical gravity currents is the persistent upwelling and downwelling motions, which are observed for both the vortex-wandering and vortex-splitting motions and were not previously documented for such flows. Depending on the Reynolds number, the bulges around the circumference of the unstable rotating cylindrical gravity currents may or may not develop into cutoff distinct circulations. The number of bulges is seen to be dependent on the ratio of Coriolis to inertia forces but independent of the Reynolds number for the range of Reynolds number considered in this study.
Multiphase nanodomains in a strained BaTiO3 film on a GdScO3 substrate
Authors: Kobayashi Shunsuke , Inoue Kazutoshi , Kato Takeharu , Ikuhara Yuichi , Yamamoto Takahisa
Published: February 2018

Controlling the crystal structure of ferroelectric materials via epitaxial strain, which is a well-known technique in strain engineering, can lead to the formation of unique domain structures generating non-intrinsic phenomena such as electronic conductivity, photovoltages, and enhanced piezoelectric characteristics. Strained BaTiO3 films are promising ferroelectric materials as theoretical modeling predicts that different domain morphologies can introduce additional properties not observed in conventional BaTiO3 ceramics. To rationally design materials for practical application, a thorough understanding of the formation mechanisms and stabilities of different domain structures in strained BaTiO3 films is required. However, there have been very few experimental reports on this topic, and details about the domain structures in strained BaTiO3 films are currently lacking. In this paper, we report multiphase nanodomains in a strained BaTiO3 film deposited on an orthorhombic GdScO3 substrate. The phase-transition behavior of the strained BaTiO3 film reveals that it contains multiple phases at room temperature; the film first undergoes a phase-transition upon heating at around 550 K, and then a paraelectric phase forms at temperatures above 690 K. A picometer-scale analysis of the Ti ion displacements, using an advanced scanning transmission electron microscopy technique, is used to characterize the complex multiphase nanodomains, providing useful insights into the control of domain structures in BaTiO3 films by applying epitaxial strain.
Orientation-dependent imaging of electronically excited quantum dots
Authors: Nguyen Duc , Goings Joshua J. , Nguyen Huy A. , Lyding Joseph , Li Xiaosong , Gruebele Martin
Published: February 2018

We previously demonstrated that we can image electronic excitations of quantum dots by single-molecule absorption scanning tunneling microscopy (SMA-STM). With this technique, a modulated laser beam periodically saturates an electronic transition of a single nanoparticle, and the resulting tunneling current modulation ΔI(x0, y0) maps out the SMA-STM image. In this paper, we first derive the basic theory to calculate ΔI(x0, y0) in the one-electron approximation. For near-resonant tunneling through an empty orbital “i” of the nanostructure, the SMA-STM signal is approximately proportional to the electron density φix0,y02 of the excited orbital in the tunneling region. Thus, the SMA-STM signal is approximated by an orbital density map (ODM) of the resonantly excited orbital at energy Ei. The situation is more complex for correlated electron motion, but either way a slice through the excited electronic state structure in the tunneling region is imaged. We then show experimentally that we can nudge quantum dots on the surface and roll them, thus imaging excited state electronic structure of a single quantum dot at different orientations. We use density functional theory to model ODMs at various orientations, for qualitative comparison with the SMA-STM experiment. The model demonstrates that our experimentally observed signal monitors excited states, localized by defects near the surface of an individual quantum dot. The sub-nanometer super-resolution imaging technique demonstrated here could become useful for mapping out the three-dimensional structure of excited states localized by defects within nanomaterials.
Raising reproducibility in dye-sensitized solar cells under laboratory conditions
Authors: Hölscher Florian , Trümper Peer-Robin , Juhász Junger Irén , Schwenzfeier-Hellkamp Eva , Ehrmann Andrea
Published: February 2018

Dye-sensitized solar cells are subject to intensive research nowadays. Their open-circuit voltage, short-circuit current, and efficiency depend on several parameters which can be optimized. Here, examinations are limited to non-toxic substances due to planned future application on textile fabrics, i.e., to TiO2, graphite, and natural dyes. During experiments on the TiO2 layer, the reproducibility of the experiment turned out to be a crucial factor, limiting the significance of the experimental findings. Thus, the main goal of this paper is the description of possibilities to standardize the production under laboratory conditions by eliminating distorting factors. Specifically, the pressure by which the glass plates with conductive coatings, serving as electrodes, are pushed together to close the solar cell was found to significantly influence the results. Different possibilities were hence tested to normalize this pressure, including different clamps and magnets. In the optimal setup, the deviations between nominally identical cells could be reduced by one order of magnitude.
Effect of shell thickness of gold-silica core-shell nanospheres embedded in an organic buffer matrix for plasmonic solar cells
Authors: N'Konou Kekeli , Many Véronique , Ruiz Carmen M. , Treguer-Delapierre Mona , Torchio Philippe
Published: February 2018

The integration of metal nanoparticles in an organic buffer matrix for plasmonic organic solar cells (OSCs) has been explored as a route for improving the photovoltaic performance, with localized electromagnetic field enhancement around nanoparticles. We investigate the optical behavior of gold-silica core-shell nanospheres (Au@SiO2 NSs) with different shell thicknesses integrated into a 30 nm-thick poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) layer which is traditionally used as a buffer layer in OSCs. The morphology and size of the chemically synthesized Au@SiO2 NSs are determined by TEM, indicating that the average diameter of the Au core is about 50 nm, while the thickness of the dielectric shell can be adjusted to around 5 or 10 nm. The effect of Au@SiO2 NSs on the surrounding electromagnetic field in such a heterogeneous matrix and subsequent multilayers is examined using a numerical simulation based on a 3D-FDTD method. Furthermore, a broadband absorption enhancement in the films, which can be primarily attributed to far-field scattering and also to the localized surface plasmon resonance around the wavelength of 530 nm, is observed in the simulated and measured absorption spectra. The analysis of the electromagnetic field between NSs and the active layer using Raman spectroscopy is also presented. The Raman spectra confirm that a plasmon effect occurs and induces a strong field enhancement; this does not change the Raman peak position but increases its signal intensity depending on the silica shell’s thickness. As a result, plasmonic devices including Au@SiO2 NSs with a 5 nm-shell thickness present the best optical behavior compared to bare NSs or 10 nm-thick shell Au@SiO2 NSs.
Time-resolved determination of the potential of zero charge at polycrystalline Au/ionic liquid interfaces
Authors: Vargas-Barbosa Nella M. , Roling Bernhard
Published: February 2018

The potential of zero charge (PZC) is a fundamental property that describes the electrode/electrolyte interface. The determination of the PZC at electrode/ionic liquid interfaces has been challenging due to the lack of models that fully describe these complex interfaces as well as the non-standardized approaches used to characterize them. In this work, we present a method that combines electrode immersion transient and impedance measurements for the determination of the PZC. This combined approach allows the distinction of the potential of zero free charge (pzfc), related to fast double layer charging on a millisecond timescale, from a potential of zero charge on a timescale of tens of seconds related to slower ion transport processes at the interface. Our method highlights the complementarity of these electrochemical techniques and the importance of selecting the correct timescale to execute experiments and interpret the results.
Highly sensitive spintronic strain-gauge sensor based on a MgO magnetic tunnel junction with an amorphous CoFeB sensing layer
Authors: Fuji Yoshihiko , Kaji Shiori , Hara Michiko , Higashi Yoshihiro , Hori Akio , Okamoto Kazuaki , Nagata Tomohiko , Baba Shotaro , Yuzawa Akiko , Otsu Kenji , Masunishi Kei , Ono Tomio , Fukuzawa Hideaki
Published: February 2018

We investigated spintronic strain-gauge sensors (Spin-SGSs) based on magnetic tunnel junctions (MTJs). To enhance the strain sensitivity of Spin-SGSs, which is defined as the gauge factor = (ΔR/R)/Δε, we investigated MgO-MTJs with an amorphous CoFeB sensing layer that exhibits high magnetostriction and soft magnetic properties. To maintain the amorphous structure of the CoFeB sensing layer even after post annealing, we applied a MgO capping layer (MgO-cap) to the CoFeB sensing layer and compared it with a Ta capping layer (Ta-cap). After post annealing at 320 °C, the CoFeB sensing layer with a MgO-cap maintained a low coercivity of 3 Oe, whereas that with a Ta-cap exhibited a high coercivity of 25 Oe. Microstructure analysis revealed that the CoFeB sensing layer with the MgO-cap has an amorphous structure because boron remains in the CoFeB sensing layer even after post annealing. The gauge factor for the Spin-SGS with the MgO-cap was 4016, which was four times larger than 942 for the Spin-SGS with the Ta-cap.
Efficient photocatalytic degradation by a silicon solar cell module with two Schottky junction TiO2/Ti electrodes
Authors: Liu Qian , Zhu Qishan , Zhang Jingjiao , Fang Liang , Tang Rujun , Shen Mingrong , Su Xiaodong
Published: February 2018

A multi-unit device for photocatalytic degradation that contained a silicon solar cell module and two TiO2/Ti electrodes was fabricated. The TiO2/Ti electrodes were connected to Al (positive) and Ag (negative) electrodes of the module. The silicon solar cell module efficiently converted photons to electron-hole pairs, and the two well-designed TiO2/Ti Schottky junction electrodes transported the electrons and holes to the planar TiO2 surface. The combination of a silicon solar cell module and TiO2 gave excellent photocatalytic degradation activity beside simple and flexible fabrication. Importantly, this device showed great potential in the degradation of organic pollutants in water bodies.
Damping of zonal modes through turbulent momentum transport
Authors: Seiferling F. , Peeters A. G. , Buchholz R. , Grosshauser S. R. , Rath F. , Weikl A.
Published: February 2018

It is shown that the radial transport of parallel momentum provides a damping mechanism for the zonal flow relevant for plasma turbulence close to the nonlinear threshold. The damping mechanism is confirmed by a “Rosenbluth-Hinton” test with a model radial momentum diffusion, in which the decay rate of the residual potential is found to be proportional to the model diffusion coefficient and in good agreement with the analytical result. Nonlinear simulations show that, when momentum transport is suppressed, stronger long wavelength zonal flow shearing occurs. The suppression of momentum transport then allows for the development of fully developed staircase structures in the E × B shear, which can suppress turbulence completely for a finite time window. No impact on shorter wavelength zonal flows is observed, in contrast to the analytical prediction which suggests a high damping rate. The latter result raises the question of the relevance the residual zonal flow plays in turbulence saturation.
Detection of transient infrared absorption of SO3 and 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH2)O(SO2)O] in the reaction CH2OO+SO2
Authors: Wang Yi-Ying , Dash Manas Ranjan , Chung Chao-Yu , Lee Yuan-Pern
Published: February 2018

We recorded time-resolved infrared absorption spectra of transient species produced on irradiation at 308 nm of a flowing mixture of CH2I2/O2/N2/SO2 at 298 K. Bands of CH2OO were observed initially upon irradiation; their decrease in intensity was accompanied by the appearance of an intense band at 1391.5 cm−1 that is associated with the degenerate SO-stretching mode of SO3, two major bands of HCHO at 1502 and 1745 cm−1, and five new bands near >1340, 1225, 1100, 940, and 880 cm−1. The band near 1340 cm−1 was interfered by absorption of SO2 and SO3, so its band maximum might be greater than 1340 cm−1. SO3 in its internally excited states was produced initially and became thermalized at a later period. The rotational contour of the band of thermalized SO3 agrees satisfactorily with the reported spectrum of SO3. These five new bands are tentatively assigned to an intermediate 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH2)O(SO2)O] according to comparison with anharmonic vibrational wavenumbers and relative IR intensities predicted for this intermediate. Observation of a small amount of cyc-(CH2)O(SO2)O is consistent with the expected reaction according to the potential energy scheme predicted previously. SO3+HCHO are the major products of the title reaction. The other predicted product channel HCOOH+SO2 was unobserved and its branching ratio was estimated to be <5%.
Efficient switching of 3-terminal magnetic tunnel junctions by the giant spin Hall effect of Pt85Hf15 alloy
Authors: Nguyen Minh-Hai , Shi Shengjie , Rowlands Graham E. , Aradhya Sriharsha V. , Jermain Colin L. , Ralph D. C. , Buhrman R. A.
Published: February 2018

Recent research has indicated that introducing impurities that increase the resistivity of Pt can enhance the efficiency of the spin Hall torque it generates. Here, we directly demonstrate the usefulness of this strategy by fabricating prototype 3-terminal in-plane-magnetized magnetic tunnel junctions that utilize the spin Hall torque from a Pt85Hf15 alloy and measuring the critical currents for switching. We find that Pt85Hf15 reduces the switching current densities compared to pure Pt by approximately a factor of 2 for both quasi-static ramped current biases and nanosecond-scale current pulses, thereby proving the feasibility of this approach in assisting the development of efficient embedded magnetic memory technologies.
Single-channel recordings of RyR1 at microsecond resolution in CMOS-suspended membranes
Authors: Hartel Andreas J. W. , Ong Peijie , Schroeder Indra , Giese M. Hunter , Shekar Siddharth , Clarke Oliver B. , Zalk Ran , Marks Andrew R. , Hendrickson Wayne A. , Shepard Kenneth L.
Published: February 2018

Significance

We present a method for measuring the conductance of ion channels at bandwidths up to 500 kHz by fabricating lipid membranes directly on the surface of a custom amplifier chip. We apply this approach to the RyR1 receptor, enabling us to identify additional closed states for calcium-dependent inactivation at microsecond temporal resolutions. Additional data analysis using extended beta distributions allows us to detect gating events as short as 35 ns, a timescale that approaches that of single-file ion translocation. These measurement techniques hold the promise of reaching timescales for studying the kinetics of ion channels, achievable now only with computer-based molecular dynamics simulations.
Endocytosis as a stabilizing mechanism for tissue homeostasis
Authors: Adler Miri , Mayo Avi , Zhou Xu , Franklin Ruth A. , Jacox Jeremy B. , Medzhitov Ruslan , Alon Uri
Published: February 2018

Significance

Many tissues in the body constantly turn over as cells divide and are replaced within weeks. Despite this turnover, tissues are able to keep proper ratios of their different cell types. How tissues attain this balance, called homeostasis, is unclear. Here we show that homeostasis can be achieved by circuits of cells that signal to each other using diffusible signals. A key negative feedback loop that stabilizes these circuits is endocytosis, a common feature of biological signaling in which a cell takes up and degrades the signal molecule that makes it divide and survive. Thus, the more of that cell type the less its numbers increase.
Impact of local symmetry breaking on the physical properties of tetrahedral liquids
Authors: Shi Rui , Tanaka Hajime
Published: February 2018

Significance

Water and silica are quite important for human beings because they are the most abundant materials with tremendous biological, geological, and technological significance. They show similar density anomalies and crystalline structures but also have differences: Water crystallizes easily on cooling, but not silica, which has a significant impact on our planet. These similarities and differences have been known for a long time, but a clear microscopic explanation is still missing. Here, we successfully reveal the microscopic physical origin of the similarities and differences between water and silica, from the local symmetric arrangement of atoms in these liquids. Our finding indicates the importance of detailed characterization of low-energy local structures for understanding the properties of liquids interacting with directional bond.
Corrosion and fouling behaviours of copper-based superhydrophobic coating
Authors: Lv Yan , Liu Mingyan
Published: February 2018

A preparation technology of superhydrophobic coating on copper substrate was studied. Surface morphology and wettability of the superhydrophobic coating were characterised. The preparation mechanism was analysed. Corrosion and fouling behaviours of the superhydrophobic coating were investigated by electrochemical workstation and immersion experiments. The results show that ultrasonic assistance can shorten etching time and improve the etching uniformity of copper substrate. The optimum fabrication process parameters of superhydrophobic coating on copper substrate were obtained. The concentration of octadecanoic acid in the ethanol solution is 0.02 mol  L−1, the immersion temperature is 35°C and the immersion time is 120 h. Under these conditions, micro–nano long-strip structure can be formed on the surface of copper substrate, and the static contact angle can be up to 157° and contact angle hysteresis is 4.2°. The superhydrophobic coating shows better anti-corrosion and anti-fouling properties on copper substrate compared with the surface of bare copper.
Circulating LL37 targets plasma extracellular vesicles to immune cells and intensifies Behçet's disease severity
Authors: Kahraman Tamer , Gucluler Gozde , Simsek Ismail , Yagci Fuat Cem , Yildirim Muzaffer , Ozen Can , Dinc Ayhan , Gursel Mayda , Ikromzoda Lolai , Sutlu Tolga , Gay Stephen , Gursel Ihsan
Published: February 2018

Behçet's disease (BD) activity is characterised by sustained, over‐exuberant immune activation, yet the underlying mechanisms leading to active BD state are poorly defined. Herein, we show that the human cathelicidin derived antimicrobial peptide LL37 associates with and directs plasma extracellular vesicles (EV) to immune cells, thereby leading to enhanced immune activation aggravating BD pathology. Notably, disease activity was correlated with elevated levels of circulating LL37 and EV plasma concentration. Stimulation of healthy PBMC with active BD patient EVs induced heightened IL1β, IFNα, IL6 and IP10 secretion compared to healthy and inactive BD EVs. Remarkably, when mixed with LL37, healthy plasma‐EVs triggered a robust immune activation replicating the pathology inducing properties of BD EVs. The findings of this study could be of clinical interest in the management of BD, implicating LL37/EV association as one of the major contributors of BD pathogenesis.

Abbreviations: BD: Behçet's disease; EV: extracellular vesicle; BB: binding buffer; AnV: annexin V; autologEV: autologous extracellular vesicles; alloEV: allogeneic extracellular vesicles
Pgam5 released from damaged mitochondria induces mitochondrial biogenesis via Wnt signaling
Authors: Bernkopf Dominic B. , Jalal Kowcee , Brückner Martina , Knaup Karl X. , Gentzel Marc , Schambony Alexandra , Behrens Jürgen
Published: February 2018

Mitochondrial abundance is dynamically regulated and was previously shown to be increased by Wnt/β-catenin signaling. Pgam5 is a mitochondrial phosphatase which is cleaved by the rhomboid protease presenilin-associated rhomboid-like protein (PARL) and released from membranes after mitochondrial stress. In this study, we show that Pgam5 interacts with the Wnt pathway component axin in the cytosol, blocks axin-mediated β-catenin degradation, and increases β-catenin levels and β-catenin–dependent transcription. Pgam5 stabilized β-catenin by inducing its dephosphorylation in an axin-dependent manner. Mitochondrial stress triggered by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) treatment led to cytosolic release of endogenous Pgam5 and subsequent dephosphorylation of β-catenin, which was strongly diminished in Pgam5 and PARL knockout cells. Similarly, hypoxic stress generated cytosolic Pgam5 and led to stabilization of β-catenin, which was abolished by Pgam5 knockout. Cells stably expressing cytosolic Pgam5 exhibit elevated β-catenin levels and increased mitochondrial numbers. Our study reveals a novel mechanism by which damaged mitochondria might induce replenishment of the mitochondrial pool by cell-intrinsic activation of Wnt signaling via the Pgam5–β-catenin axis.
Synthesis of Nanomaterials by the Pulsed Plasma in Liquid and their Bio-medical Applications
Authors: Omurzak E , Abdullaeva Z , Satyvaldiev A , Zhasnakunov Z , Kelgenbaeva Z , Adil Akai Tegin R , Syrgakbek kyzy D , Doolotkeldieva T , Bobusheva S , Mashimo T
Published: February 2018

Pulsed plasma in liquid is a simple, ecologically friendly, cost-efficient method based on electrical discharge between two metal electrodes submerged into a dielectric liquid. We synthesized carbon-encapsulated Fe (Fe@C) magnetic nanoparticles with low cytotoxicity using pulsed plasma in a liquid. Body-centered cubic Fe core nanoparticles showed good crystalline structures with an average size between 20 and 30 nm were encapsulated in onion-like carbon coatings with a thickness of 2–10 nm. Thermal gravimetric analysis showed a high stability of the as-synthesized samples under thermal treatment and oxidation. Cytotoxicity measurements showed higher cancer cell viability than samples synthesized by different methods. Carbon coated ZnO nanorods with about 20 nm thickness and 150 nm length were synthesized by this method using different surfactant materials such as cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS). Cu and Ag nanoparticles of about 10 nm in size were also synthesized by the pulsed plasma in aquatic solution of 0.2 % gelatine as surfactant material. These nanoparticles showed high antibacterial activity for Erwinia amylovora and Escherichia coli.
Comparative Efficacy of Antihypertensive Agents in Salt-Sensitive Hypertensive Patients: A Network Meta-Analysis
Authors: Qi Han , Liu Zheng , Cao Han , Sun Wei-Ping , Peng Wen-Juan , Liu Bin , Dong Sheng-Jie , Xiang Yu-Tao , Zhang Ling
Published: February 2018

BACKGROUND

Salt-sensitive hypertension (SSH) is an intermediate inherited phenotype of essential hypertension as well as being an independent risk factor for cardiovascular disease. However, effective medications for the treatment of SSH have not been clarified. This study was to compare the efficacious of different classes of antihypertensive agents combined with salt intake on the reduction of blood pressure (BP) in patients with SSH.

METHODS

We used sources as PubMed, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), CNKI, and WANFANG database from inception to November 2016. Studies that compared the efficacy of 2 or more antihypertensive agents or placebos in adult salt-sensitive hypertensive patients were included. The outcomes included variations in mean arterial blood pressure, systolic and diastolic blood pressure.

RESULTS

Twenty-five studies were involved in this meta-analysis. A calcium channel blocker (CCB) with hydrochlorothiazide and moderate salt intake was significantly the most efficacious in comparison with placebo (standardized mean differences (SMD), 95% credibility intervals (CI): 26.66, 12.60 to 40.16), angiotensin receptor blockers (ARBs) (SMD, 95% CI: 22.94, 5.26 to 40.51), and the other interventions for patients with SSH and no concomitant diseases. For SSH patients who were obese, CCB with metformin and moderate salt intake would decrease blood pressure with 17.90 mm Hg.

CONCLUSIONS

For SSH patients with no concomitant diseases, CCB combined with hydrochlorothiazide and moderate salt intake was optimal in reducing BP, while CCB combined with metformin and moderate salt intake was the most efficacious at reducing BP in SSH patients with coexisting obesity.
Advanced lesion symptom mapping analyses and implementation as BCBtoolkit
Authors: Foulon Chris , Cerliani Leonardo , Kinkingnéhun Serge , Levy Richard , Rosso Charlotte , Urbanski Marika , Volle Emmanuelle , Thiebaut de Schotten Michel
Published: February 2018

Background

Patients with brain lesions provide a unique opportunity to understand the functioning of the human mind. However, even when focal, brain lesions have local and remote effects that impact functionally and structurally connected circuits. Similarly, function emerges from the interaction between brain areas rather than their sole activity. For instance, category fluency requires the associations between executive, semantic, and language production functions.

Findings

Here, we provide, for the first time, a set of complementary solutions for measuring the impact of a given lesion on the neuronal circuits. Our methods, which were applied to 37 patients with a focal frontal brain lesions, revealed a large set of directly and indirectly disconnected brain regions that had significantly impacted category fluency performance. The directly disconnected regions corresponded to areas that are classically considered as functionally engaged in verbal fluency and categorization tasks. These regions were also organized into larger directly and indirectly disconnected functional networks, including the left ventral fronto-parietal network, whose cortical thickness correlated with performance on category fluency.

Conclusions

The combination of structural and functional connectivity together with cortical thickness estimates reveal the remote effects of brain lesions, provide for the identification of the affected networks, and strengthen our understanding of their relationship with cognitive and behavioral measures. The methods presented are available and freely accessible in the BCBtoolkit as supplementary software [1].
Geostatistical regularization operators for geophysical inverse problems on irregular meshes
Authors: Jordi C , Doetsch J , Günther T , Schmelzbach C , Robertsson J OA
Published: February 2018

Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.
Maintenance of Certification: Perceptions and Attitudes of Neurosurgeons
Authors: Babu Maya A , Liau Linda M , Connolly E Sander , Meyer Fredric B
Published: February 2018

Assuring clinical competence throughout the career of a neurosurgeon is of paramount importance for patient safety. We present the first comprehensive survey of all neurosurgeons board certified through the American Board of Neurological Surgery (ABNS) to evaluate perceptions of Maintenance of Certification (MOC). We administered a validated, online, confidential survey to 4899 neurosurgeons (2435 ABNS diplomates participating in MOC, 1440 diplomates certified prior to 1999 [time-unlimited certificates], and 1024 retired diplomates). We received 1449 responses overall (30% response rate). Our study found that most respondents believe that neurosurgeons should be required to participate in continuing professional improvement following initial board certification (75%). Most believe that specialty boards, working in conjunction with specialty societies, should require diplomates to participate in programs meant to promote continuous professional development (73%). The majority of respondents (76%) believed that self-assessment tests constituted a meaningful professional development activity, in addition to periodic case log reviews (33%) or quality improvement projects (32.6%). A plurality of respondents (44%) do not feel that the MOC process as currently structured provides them with value. There were no differences between those who were “grandfathered” and those who actively participate in MOC and no differences between those in private practice versus those in academics. The ABNS is cognizant of diplomate concerns and is actively developing new MOC paradigms to ensure that the process achieves both the goals of meeting the public interest and assuring that the quality of American neurosurgery remains exemplary.
Appendiceal Endometriosis and Ectopic Pregnancy Occurring Simultaneously
Authors: Chemerinski Anat , Lubin Daniel , Holder Sevelle , Shah Divya
Published: February 2018

BACKGROUND:

In the setting of a known ectopic pregnancy, severe abdominal pain with clinical concern for rupture is an indication for emergency surgery. In rare cases, appendiceal pathology may occur simultaneously.

CASE:

A woman with a known ectopic pregnancy presented to the emergency department with a clinical picture consistent with its rupture. At the time of surgery, an appendectomy also was performed owing to concern for concurrent appendicitis; histopathologic examination revealed appendiceal endometriosis.

CONCLUSION:

During surgical management of ectopic pregnancy, it is important to undertake a thorough examination of the pelvis, because patients may present with multiple concurrent pathologies. In the setting of an emergency operation, when the diagnosis seems clear, this survey should not be forgotten.
Rate of Pelvic Organ Prolapse Surgery Among Privately Insured Women in the United States, 2010–2013
Authors: Sammarco Anne G. , Swenson Carolyn W. , Kamdar Neil S. , Kobernik Emily K. , DeLancey John O. L. , Nallamothu Brahmajee , Morgan Daniel M.
Published: February 2018

OBJECTIVE:

To analyze utilization of, and payments for, pelvic organ prolapse procedures after the 2011 U.S. Food and Drug Administration (FDA) communication regarding transvaginal mesh.

METHODS:

This is a retrospective cohort study examining private claims from three insurance providers for inpatient and outpatient prolapse procedures from 2010 to 2013 in the Health Care Cost Institute. Primary outcomes were the change in utilization of prolapse procedures, with and without mesh, before and after the July 2011 FDA communication. Secondary outcomes were the changes in payments and reimbursements for these procedures. Utilization rates and payments were compared using generalized linear models and interrupted time-series analysis.

RESULTS:

Utilization of prolapse procedures decreased from 12.3 to 9.7 per 10,000 woman-years (P=.027) with a decrease of 30.7% (3.9 in 2010 to 2.7 in 2013, P=.05) in number of mesh procedures and 16.6% (8.4 in 2010 to 7.0 in 2013, P=.011) for nonmesh procedures. Quarterly utilization of mesh procedures was increasing before the FDA communication and then significantly declined after its release (slope=0.024 vs −0.025, P=.002). Nonmesh procedures, however, were already slightly decreasing before July 2011 and continued to decline at a more rapid pace after that time, although not significantly (slope=−0.004 vs −0.022, P=.47). Inpatient utilization decreased 52.2% (P=.002), whereas outpatient utilization increased 18.5% (P=.132). Payments for individual inpatient procedures, with and without mesh, increased by 12.0% ($8,315 in 2010 to $9,315 in 2013, P=.001) and 15.6% ($7,826 in 2010 to $9,048 in 2013, P=.005), respectively, whereas those for outpatient procedures increased by 41% ($4,961 in 2010 to $6,981 in 2013, P=.006) and 30% ($3,955 in 2010 to $5,149 in 2013, P=.004), respectively.

CONCLUSION:

Use of prolapse surgery declined during the study period. After the 2011 FDA communication regarding transvaginal mesh, there was a significant decrease in the utilization of procedures with mesh but not for those without mesh. A shift toward outpatient surgeries was observed, and payments for both individual inpatient and outpatient cases increased.
Preventing Mitochondrial Disease
Authors: Adashi Eli Y. , Cohen I. Glenn
Published: February 2018

In a possible first, the heritable transmission of a fatal mitochondrial DNA disease (Leigh syndrome) may have been prevented by replacing the mutation-bearing mitochondria of oocytes with donated mutation-free counterparts. The procedure, carried out by a U.S.-led team, took place in Mexico in circumvention of a statutory U.S. moratorium on mitochondrial replacement. This development calls into question the regulatory utility of a national moratorium in a globalized world wherein cross-border care is increasingly prevalent. This development also calls to account the moral defensibility of a moratorium that acquiesces in the birth of gravely ill children whose afflictions could have been prevented. In this Current Commentary, we outline a potential path forward by analyzing the dual imprint of the moratorium, examining its legislative shortcomings, exploring its motivational roots, considering its national effect, and proposing its unlinking from the related yet distinct ban on editing the genome of the human embryo.
Implementing Innovations in Global Women's, Children's, and Adolescents' Health
Authors: Peterson Herbert B. , Haidar Joumana , Fixsen Dean , Ramaswamy Rohit , Weiner Bryan J. , Leatherman Sheila
Published: February 2018

The launch of the United Nations Sustainable Development Goals and the new Secretary General's Global Strategy for Women's, Children's, and Adolescents' Health are a window of opportunity for improving the health and well-being of women, children, and adolescents in the United States and around the world. Realizing the full potential of this historic moment will require that we improve our ability to successfully implement life-saving and life-enhancing innovations, particularly in low-resource settings. Implementation science, a new and rapidly evolving field that addresses the “how-to” component of providing sustainable quality services at scale, can make an important contribution on this front. A synthesis of the implementation science evidence indicates that three interrelated factors are required for successful, sustainable outcomes at scale: 1) effective innovations, 2) effective implementation, and 3) enabling contexts. Implementation science addresses the interaction among these factors to help make innovations more usable, to build ongoing capacity to assure the effective implementation of these innovations, and to ensure enabling contexts to sustain their full and effective use in practice. Improving access to quality services will require transforming health care systems and, therefore, much of the focus of implementation science in global health is on improving the ability of health systems to serve as enabling contexts. The field of implementation science is inherently interdisciplinary and academe will need to respond by facilitating collaboration among scientists from relevant disciplines, including evaluation, improvement, and systems sciences. Platforms and programs to facilitate collaborations among researchers, practitioners, policymakers, and funders are likewise essential.
Risk of Adverse Pregnancy Outcomes at Advanced Maternal Age
Authors: Frederiksen Line Elmerdahl , Ernst Andreas , Brix Nis , Braskhøj Lauridsen Lea Lykke , Roos Laura , Ramlau-Hansen Cecilia Høst , Ekelund Charlotte Kvist
Published: February 2018

OBJECTIVE:

To study the possible associations between advanced maternal age and risk of selected adverse pregnancy outcomes.

METHODS:

The study used a nationwide cohort of 369,516 singleton pregnancies in Denmark followed from 11–14 weeks of gestation to delivery or termination of pregnancy. Pregnant women aged 35 years or older were divided into two advanced maternal age groups, 35–39 years and 40 years or older, and compared with pregnant women aged 20–34 years. Adverse pregnancy outcomes were chromosomal abnormalities, congenital malformations, miscarriage, stillbirth, and birth before 34 weeks of gestation. Multivariable logistic regression analyses were performed to investigate associations between advanced maternal age and adverse pregnancy outcomes. Furthermore, a risk prediction model for a composite adverse pregnancy outcome was made with prespecified predicting factors.

RESULTS:

Among the pregnant women aged 40 years or older, 10.82% experienced one or more of the selected adverse pregnancy outcomes compared with 5.46% of pregnant women aged 20–34 years (odds ratio [OR] 2.02, 99.8% CI 1.78–2.29). When pregnant women 40 years or older were compared with women aged 20–34 years, they had a higher risk of chromosomal abnormalities (3.83% vs 0.56%, OR 7.44 [CI 5.93–9.34]), miscarriage (1.68% vs 0.42%, OR 3.10 [CI 2.19–4.38]), and birth before 34 weeks of gestation (2.01% vs 1.21%, OR 1.66 [CI 1.23–2.24]), but no increased risk of congenital malformations and stillbirth. The risk prediction chart showed that advanced maternal age, use of assisted reproductive technology, nulliparous pregnancy, smoking during pregnancy, and obesity increased the absolute predictive risk of an adverse pregnancy outcome.

CONCLUSION:

Women older than 40 years have a higher risk of chromosomal abnormalities, miscarriage, and birth before 34 weeks of gestation than younger women and should be monitored accordingly. No increased risk was observed for stillbirth and other congenital malformations. Several factors increase the risk of adverse pregnancy outcomes, but advanced maternal age drives a high proportion of the total risk score.
What Is New in Cannabis Use in Pregnancy?
Authors: Metz Torri D.
Published: February 2018

This month we focus on current research in cannabis use in pregnancy. Dr. Metz discusses four recent publications, which are concluded with a “bottom line” that is a take-home message. A complete reference for each can be found in Box 1 on this page along with direct links to abstracts.
Is Overall Mortality the Right Composite Endpoint in Clinical Trials of Acute Respiratory Distress Syndrome?*
Authors: Villar Jesús , Martínez Domingo , Mosteiro Fernando , Ambrós Alfonso , Añón José M. , Ferrando Carlos , Soler Juan A. , Montiel Raquel , Vidal Anxela , Conesa-Cayuela Luís A. , Blanco Jesús , Arrojo Regina , Solano Rosario , Capilla Lucía , del Campo Rafael , Civantos Belén , Fernández María Mar , Aldecoa César , Parra Laura , Gutiérrez Andrea , Martínez-Jiménez Chanel , González-Martín Jesús M. , Fernández Rosa L. , Kacmarek Robert M.
Published: February 2018

Objectives:

Overall mortality in patients with acute respiratory distress syndrome is a composite endpoint because it includes death from multiple causes. In most acute respiratory distress syndrome trials, it is unknown whether reported deaths are due to acute respiratory distress syndrome or the underlying disease, unrelated to the specific intervention tested. We investigated the causes of death after contracting acute respiratory distress syndrome in a large cohort.

Design:

A secondary analysis from three prospective, multicenter, observational studies.

Setting:

A network of multidisciplinary ICUs.

Patients:

We studied 778 patients with moderate-to-severe acute respiratory distress syndrome treated with lung-protective ventilation.

Interventions:

None.

Measurements and Main Results:

We examined death in the ICU from individual causes. Overall ICU mortality was 38.8% (95% CI, 35.4–42.3). Causes of acute respiratory distress syndrome modified the risk of death. Twenty-three percent of deaths occurred from refractory hypoxemia due to nonresolving acute respiratory distress syndrome. Most patients died from causes unrelated to acute respiratory distress syndrome: 48.7% of nonsurvivors died from multisystem organ failure, and cancer or brain injury was involved in 37.1% of deaths. When quantifying the true burden of acute respiratory distress syndrome outcome, we identified 506 patients (65.0%) with one or more exclusion criteria for enrollment into current interventional trials. Overall ICU mortality of the “trial cohort” (21.3%) was markedly lower than the parent cohort (relative risk, 0.55; 95% CI, 0.43–0.70; p < 0.000001).

Conclusions:

Most deaths in acute respiratory distress syndrome patients are not directly related to lung damage but to extrapulmonary multisystem organ failure. It would be challenging to prove that specific lung-directed therapies have an effect on overall survival.
Elevated Venous Thromboembolism Risk Following Colectomy for IBD Is Equal to Those for Colorectal Cancer for Ninety Days After Surgery
Authors: Ali Fadwa , Al-Kindi Sadeer G. , Blank Jacqueline J. , Peterson Carrie Y. , Ludwig Kirk A. , Ridolfi Timothy J.
Published: February 2018

BACKGROUND:

The risk of postoperative venous thromboembolism is high in patients with colon cancer and IBD. Although The American Society of Colon and Rectal Surgeons suggests posthospital prophylaxis after surgery in patients with colon cancer, there are no such recommendations for patients with IBD.

OBJECTIVE:

This study aims to analyze the incidence and risk factors for postoperative venous thromboembolism.

DESIGN:

This was a retrospective review using the Explorys platform.

SETTINGS:

Aggregated electronic medical records from 26 major health care systems across the United States from 1999 to 2017 were used for this study.

PATIENTS:

Patients who underwent colon surgery were included.

MAIN OUTCOME MEASURES:

Patients were followed up to 90 days postoperatively for deep vein thrombosis and pulmonary embolism.

RESULTS:

A total of 75,620 patients underwent colon resections, including 32,020 patients with colon cancer, 9850 patients with IBD, and 33,750 patients with diverticulitis. The 30-day incidence of venous thromboembolism was higher in patients with cancer and IBD than in patients with diverticulitis (2.9%, 3.1%, and 2.4%, p < 0.001 for both comparisons). The 30-day incidence of venous thromboembolism in patients with ulcerative colitis is greater than in patients with Crohn’s disease (4.1% vs 2.1%, p < 0.001). The cumulative incidence of venous thromboembolism increased from 1.2% at 7 days after surgery to 4.3% at 90 days after surgery in patients with cancer, and from 1.3% to 4.3% in patients with IBD. In multivariable analysis, increase in the risk of venous thromboembolism was associated with cancer diagnosis, IBD diagnosis, age ≥60, smoking, and obesity.

LIMITATIONS:

This study was limited by its retrospective nature and by the use of the aggregated electronic database, which is based on charted codes and contains only limited collateral clinical data.

CONCLUSIONS:

Because of the elevated and sustained risk of postoperative thromboembolism, patients with IBD, especially ulcerative colitis, might benefit from extended thromboembolism prophylaxis similar to that of patients with colon cancer. See Video Abstract at http://links.lww.com/DCR/A544.