bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the consistency assumptions underlying network meta‐regression using aggregate data
Authors: Donegan Sarah , Dias Sofia , Welton Nicky J.
Published: October 2018

When numerous treatments exist for a disease (Treatments 1, 2, 3, etc), network meta‐regression (NMR) examines whether each relative treatment effect (eg, mean difference for 2 vs 1, 3 vs 1, and 3 vs 2) differs according to a covariate (eg, disease severity). Two consistency assumptions underlie NMR: consistency of the treatment effects at the covariate value 0 and consistency of the regression coefficients for the treatment by covariate interaction. The NMR results may be unreliable when the assumptions do not hold. Furthermore, interactions may exist but are not found because inconsistency of the coefficients is masking them, for example, when the treatment effect increases as the covariate increases using direct evidence but the effect decreases with the increasing covariate using indirect evidence.

We outline existing NMR models that incorporate different types of treatment by covariate interaction. We then introduce models that can be used to assess the consistency assumptions underlying NMR for aggregate data. We extend existing node‐splitting models, the unrelated mean effects inconsistency model, and the design by treatment inconsistency model to incorporate covariate interactions. We propose models for assessing both consistency assumptions simultaneously and models for assessing each of the assumptions in turn to gain a more thorough understanding of consistency.

We apply the methods in a Bayesian framework to trial‐level data comparing antimalarial treatments using the covariate average age and to four fabricated data sets to demonstrate key scenarios.

We discuss the pros and cons of the methods and important considerations when applying models to aggregated data.
Predictive factors for adrenal metastasis in extra‐adrenal malignancy patients with solitary adrenal mass
Authors: Byeon Kyeong‐Hyeon , Ha Yun‐Sok , Choi Seock‐Hwan , Kim Bum Soo , Kim Hyun Tae , Yoo Eun Sang , Kwon Tae Gyun , Lee Jun Nyung , Kim Tae‐Hwan
Published: October 2018

Background and Objectives

The adrenal gland is a frequent site for metastasis, and a solitary adrenal mass is often observed during staging workup or imaging follow‐up in patients with extra‐adrenal malignancy. To create an appropriate management plan, it is essential to distinguish between benign adrenal lesions and metastasis in patients with extra‐adrenal cancer having solitary adrenal masses. Therefore, here we evaluated the predictive factors for adrenal metastasis in patients with extra‐adrenal malignancy having solitary adrenal mass.

Materials and Methods

From September 2003 to June 2016, we retrospectively reviewed patients with extra‐adrenal malignancy having solitary adrenal mass on a cancer staging workup or follow‐up study who subsequently underwent adrenalectomy at our institution. All patients underwent preoperative functional studies; those with positive results were excluded from this study. Characteristics of oncology patients with adrenal mass including age, sex, body mass index, smoking, mass location, mass size, hypertension, diabetes mellitus, precontrast Hounsfield unit (HU), and synchronous or metachronous adrenal mass based on the time of the extra‐adrenal cancer diagnosis were analyzed.

Results

Of the total 68 patients with extra‐adrenal cancer having solitary adrenal mass, 22 had pathologically confirmed adrenal metastasis. Primary cancers consisted of hepatocellular cell carcinoma (n = 7), renal cell carcinoma (n = 7), lung cancer (n = 4), colon cancer (n = 3), and breast cancer (n = 1). On multivariate analysis, a higher precontrast HU (P = 0.001, odds ratio [OR] = 1.105, 95% confidence interval [CI] = 1.042‐1.172), male sex (
P = 0.019, OR = 9.782, 95% CI = 1.462‐65.461), and metachronous adrenal mass (
P = 0.007, OR = 11.090, 95% CI = 1.937‐63.490) were observed as predictive factors for adrenal metastasis in patients with extra‐adrenal cancer having solitary adrenal mass. The cut‐off value of precontrast HU to distinguish between metastasis and benign lesions was 36.2 (sensitivity = 81.8%; specificity = 91.3%).

Conclusion

High precontrast HU (> 36), male sex, and metachronous adrenal mass are predictive factors for adrenal metastasis in patients with extra‐adrenal malignancy having solitary adrenal mass.
The distribution pattern of metastatic lymph nodes after non‐curative endoscopic resection in early gastric cancer
Authors: Arroyo‐Martinez Quetzalihuitl , Han Won Ho , Eom Bang Wool , Yoon Hong Man , Kim Young Il , Cho Soo Jeong , Lee Jong Yeul , Kim Chan Gyoo , Morales‐Conde Salvador , Padillo‐Ruiz Javier , Kook Myeong‐Cherl , Choi Il Ju , Kim Young Woo , Ryu Keun Won
Published: October 2018

Background and Objectives

Additional surgery should be done after non‐curative endoscopic resection (ER) in early gastric cancer (EGC) due to the risk of lymph node metastasis (LNM). However, the distribution pattern of LNM in these patients is complicated and unpredictable. The aim of this study is to identify any different distribution patterns of LNM in patients with EGC who underwent additional surgery after non‐curative (ER) comparing to those without ER.

Methods

Patients who underwent surgery for EGC between 2001 and 2016 were included. Enrolled patients were divided into two groups, those who underwent additional surgery after non‐curative ER and those who underwent direct surgery without a history of ER. Demographics, tumor characteristics and LNM distribution pattern were analyzed.

Results

Among 4295 patients with EGC, 404 patients had a history of preoperative ER, and 3891 patients did not. After the application of exclusion criteria, 23 (7.1%) of 322 patients undergoing additional surgery had LNM. The additional surgery group showed less LNM, fewer nodal stations and more restricted distribution pattern of LNM.

Conclusions

The distribution pattern of LNM in EGC is complicated. However, more restricted locoregional LNM could be expected in cases of additional surgery after non‐curative ER than after direct surgery.
Critical evaluation of microextraction pretreatment techniques—Part 2: Membrane‐supported and homogenous phase based techniques
Authors: Havlikova Martina , Cabala Radomir , Pacakova Vera , Bosakova Zuzana
Published: October 2018

This review follows up on Part 1, which focused on classification and evaluation of single drop and sorbent‐based microextraction techniques. Membrane‐ and homogenous phase‐based microextraction techniques are discussed and classified in Part 2. These techniques are more recent than those in Part 1 and considerable attention has been paid to their development. The new methodologies are more sensitive and, thanks to their miniaturization, they can be classified as “green”, but no exhaustive classification is available. We hope that this review will contribute to better orientation in these methods.
Maleic anhydride‐modified polyolefins as compatibilizer for lignin‐reinforced polypropylene composites
Authors: Chen Fenggui , Zhang Mingzhong
Published: October 2018

Lignin is an attractive renewable reinforcing agent for polyolefins, which is also an excellent free‐radical scavenger and promising low‐cost antioxidant for polymers, however, exhibiting poor compatibility with non‐polar polymers. In this work, modified polyolefins containing maleic anhydride group like polybond (PB) were used as compatibilizer and incorporated into polypropylene (PP) with lignin to improve the blending ability of the polar filler in the non‐polar matrix. The composite containing individual lignin possesses a much smaller elongation at break than neat PP, whereas owing to the significantly improved dispersion by compatibilizer, the incorporation of compatibilizer into PP/lignin blends gives rise to remarkably increased elongation at break. Besides, lignin greatly slows down the UV‐induced degradation of PP and dramatically enhances anti‐oxidant effect of PP composites in the existence of compatibilizer, in which the elongation at break of PP/PB/2%lignin retains 77% of its original value when it reduces by 92% for neat PP after 240 h of UV irradiation. POLYM. COMPOS., 40:2594–2601, 2019. © 2018 Society of Plastics Engineers
Prenatal screening for Down syndrome in twin pregnancies: Estimates of screening performance based on 61 affected and 7302 unaffected twin pregnancies
Authors: Wald Nicholas J. , Bestwick Jonathan P. , Huttly Wayne J. , Aldis Jonathan , Borrell Antoni , Goodburn Sandy , Mills Ian
Published: October 2018

The aims of this study were to determine whether assumptions used in prenatal screening for Down syndrome in twin pregnancies are valid and derive estimates of risk and screening performance in twin pregnancies using observed data. Data were collected on nuchal translucency, chorionicity, pregnancy associated plasma protein‐A (PAPP‐A), and free ß human chorionic gonadotrophin (free ß‐hCG) from 61 twin pregnancies with Down syndrome and 7302 unaffected twin pregnancies. Distribution parameters were determined and used to estimate screening performance. The assumption that proportional differences in serum marker levels in affected and unaffected singleton pregnancies apply to twin pregnancies was not confirmed. Median free β‐hCG value in monochorionic affected twin pregnancies (2.63 multiples of the median [MoM]; 95% CI, 1.79‐3.22 MoM) was lower than that assuming proportionality (3.76 MoM), and the median PAPP‐A value in dichorionic affected twin pregnancies (1.88 MoM; 95% CI, 1.60‐2.17 MoM) was higher than that based on proportionality (1.33 MoM). The detection rate was 87% for a 3% false‐positive rate in monochorionic twin pregnancies and 74% in dichorionic twin pregnancies compared with 86% in singleton pregnancies. Estimates of screening performance in Down syndrome twin pregnancies do not need to rely on assumptions and can take account of chorionicity and gestational age.
Sulforaphane promotes chlamydial infection by suppressing mitochondrial protein oxidation and activation of complement C3
Authors: Saez Daniel , Dushime Rosine , Wu Hanzhi , Ramos Cordova Lourdes B. , Shukla Kirtikar , Brown‐Harding Heather , Furdui Cristina M. , Tsang Allen W.
Published: October 2018

Sulforaphane (SFN), a phytochemical found in broccoli and other cruciferous vegetables, is a potent antioxidant and anti‐inflammatory agent with reported effects in cancer chemoprevention and suppression of infection with intracellular pathogens. Here we report on the impact of SFN on infection with Chlamydia trachomatis (Ct), a common sexually transmitted pathogen responsible for 131 million new cases annually worldwide. Astoundingly, we find that SFN as well as broccoli sprouts extract (BSE) promote Ct infection of human host cells. Both the number and size of Ct inclusions were increased when host cells were pretreated with SFN or BSE. The initial investigations presented here point to both the antioxidant and thiol alkylating properties of SFN as regulators of Ct infection. SFN decreased mitochondrial protein sulfenylation and promoted Ct development, which were both reversed by treatment with mitochondria‐targeted paraquat (MitoPQ). Inhibition of the complement component 3 (complement C3) by SFN was also identified as a mechanism by which SFN promotes Ct infections. Mass spectrometry analysis found alkylation of cysteine 1010 (Cys1010) in complement C3 by SFN. The studies reported here raise awareness of the Ct infection promoting activity of SFN, and also identify potential mechanisms underlying this activity.
Glutamate dehydrogenase: Structure of a hyperinsulinism mutant, corrections to the atomic model, and insights into a regulatory site
Authors: Nassar Omneya M. , Li Changhong , Stanley Charles A. , Pettitt B. Montgomery , Smith Thomas J.
Published: October 2018

Mammalian glutamate dehydrogenase (GDH) has complex allosteric regulation and the loss of GTP inhibition causes the hyperinsulinism/hyperammonemia syndrome (HHS) where insulin is hypersecreted upon consumption of protein. The archetypical HHS lesion is H454Y and lies in the GTP binding pocket. To better understand the mechanism of HHS, we determined the crystal structure of H454Y. When the bovine GDH crystal structures were minimized to prepare for further computational analysis, unusually large deviations were found at the allosteric NADH binding site due to chemical sequence errors. Notably, 387 lies in an allosteric where several activators and inhibitors bind and should be lysine rather than asparagine. All structures were re‐refined and the consequence of this sequence error on NADH binding was calculated using free energy perturbation. The binding free energy penalty going from the correct to incorrect sequence found is +5 kcal/mol per site and therefore has a significant impact on drug development.

Broader Audience Abstract

Glutamate dehydrogenase is a key enzyme involved in amino acid catabolism. As such, it is heavily regulated in animals by a wide array of metabolites. The importance of this regulation is most apparent in a genetic disorder called hyperinsulinism/hyperammonemia (HHS) where patients hypersecrete insulin upon the consumption of protein. We determined the atomic structure of one of these HHS mutants to better understand the disease and also analyzed an allosteric regulatory site.
Computational investigation of the conformational dynamics in Tom20‐mitochondrial presequence tethered complexes
Authors: Srivastava Arpita , Tama Florence , Kohda Daisuke , Miyashita Osamu
Published: October 2018

The translocase of the outer membrane (TOM) mediates the membrane permeation of mitochondrial matrix proteins. Tom20 is a subunit of the TOM complex and binds to the N‐terminal region (ie, presequence) in mitochondrial matrix precursor proteins. Previous experimental studies indicated that the presequence recognition by Tom20 was achieved in a dynamic‐equilibrium among multiple bound states of the α‐helical presequence. Accordingly, the co‐crystallization of Tom20 and a presequence peptide required a disulfide‐bond cross‐linking. A 3‐residue spacer sequence (XAG) was inserted between the presequence and the anchoring Cys residue at the C‐terminus to not disturb the movement of the presequence peptide in the binding site of Tom20. Two crystalline forms were obtained according to Ala or Tyr at the X position of the spacer sequence, which may reflect the dynamic‐equilibrium of the presequence. Here, we have performed replica‐exchange molecular dynamics (REMD) simulations to study the effect of disulfide‐bond linker and single amino acid difference in the spacer region of the linker on the conformational dynamics of Tom20‐presequence complex. Free energy and network analyses of the REMD simulations were compared against previous simulations of non‐tethered system. We concluded that the disulfide‐bond tethering did not strongly affect the conformational ensemble of the presequence peptide in the complex. Further investigation showed that the choice of Ala or Tyr at the X position did not affect the most distributions of the conformational ensemble of the presequence. The present study provides a rational basis for the disulfide‐bond tethering to study the dynamics of weakly binding complexes.
Characterization of myofiber‐type‐specific molecules using mass spectrometry imaging
Authors: Goto‐Inoue Naoko , Morisasa Mizuki , Machida Kazumasa , Furuichi Yasuro , Fujii Nobuharu L. , Miura Shinji , Mori Tsukasa
Published: October 2018

Rationale

In skeletal muscles, there are four myofiber types, Types I, IIa, IIx, and IIb, which show different contraction characteristics and have different metabolic statuses. To understand muscle function, it is necessary to analyze myofiber‐specific metabolic changes. However, these fibers are heterogeneous and are hard to discriminate by conventional analyses using tissue extracts. In this study, we found myofiber‐specific molecules and molecular markers of other cells such as smooth muscle cells, fat cells, and motor neurons, and visualized them within muscle sections.

Methods

We used three different muscle tissues, namely extensor digitorum longus, soleus, and gastrocnemius tissues, from ICR mice. After the muscles had been harvested, cross‐sections were prepared using a cryostat and analyzed using matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), and conventional immunofluorescence imaging.

Results

By comparing the MALDI MSI results with the immunofluorescence imaging results, we were able to identify each fiber and cell‐specific ion. It was especially important that we could find Type IIa and IIb specific ions, because these were difficult to distinguish.

Conclusions

Through MSI analyses, we performed a comprehensive survey to identify cell‐ and myofiber‐specific molecular markers. In conclusion, we assigned muscle fiber Type I, IIa, and IIb‐specific molecular ions at m/z 856.6, 872.6, and 683.8, respectively. These molecular markers might be useful for verifying changes that occur due to exercise and/or disease.
Fully autonomous micro air vehicle flight and landing on a moving target using visual–inertial estimation and model‐predictive control
Authors: Tzoumanikas Dimos , Li Wenbin , Grimm Marius , Zhang Ketao , Kovac Mirko , Leutenegger Stefan
Published: October 2018

The Mohamed Bin Zayed International Robotics Challenge (MBZIRC) held in spring 2017 was a very successful competition well attended by teams from all over the world. One of the challenges (Challenge 1) required an aerial robot to detect, follow, and land on a moving target in a fully autonomous fashion. In this paper, we present the hardware components of the micro air vehicle (MAV) we built with off the self components alongside the designed algorithms that were developed for the purposes of the competition. We tackle the challenge of landing on a moving target by adopting a generic approach, rather than following one that is tailored to the MBZIRC Challenge 1 setup, enabling easy adaptation to a wider range of applications and targets, even indoors, since we do not rely on availability of global positioning system. We evaluate our system in an uncontrolled outdoor environment where our MAV successfully and consistently lands on a target moving at a speed of up to 5.0 m/s.
The ETH‐MAV Team in the MBZ International Robotics Challenge
Authors: Bähnemann Rik , Pantic Michael , Popović Marija , Schindler Dominik , Tranzatto Marco , Kamel Mina , Grimm Marius , Widauer Jakob , Siegwart Roland , Nieto Juan
Published: October 2018

This study describes the hardware and software systems of the Micro Aerial Vehicle (MAV) platforms used by the ETH Zurich team in the 2017 Mohamed Bin Zayed International Robotics Challenge (MBZIRC). The aim was to develop robust outdoor platforms with the autonomous capabilities required for the competition, by applying and integrating knowledge from various fields, including computer vision, sensor fusion, optimal control, and probabilistic robotics. This paper presents the major components and structures of the system architectures and reports on experimental findings for the MAV‐based challenges in the competition. Main highlights include securing the second place both in the individual search, pick, and place the task of Challenge 3 and the Grand Challenge, with autonomous landing executed in less than 1 min and a visual servoing success rate of over for object pickups.
Force‐based perception and manipulation, the DTU team competing in MBZIRC 2017
Authors: Bilberg Christopher Prinds , Witting Christian Aamand , Andersen Nils Axel , Ravn Ole
Published: October 2018

This paper presents how the team from the Technical University of Denmark (DTU) implemented and solved the second challenge of the Mohamed Bin Zayed International Robotics Challenge. The competition was imitating a disaster scene where a robotic platform had to operate autonomously in a partly known environment to localize and manipulate a valve on a panel. To solve the given problem, the robot needs to be able to perceive the environment reliably. This is often accomplished using vision based solutions, however these might not always be feasible. Thus we show how force feedback can successfully be used as an alternative way of perception. To accomplish this the team equipped a robot arm with a force torque sensor, allowing the robot to perceive its environment through direct contact. This approach resulted in a robust solution of the task, independent of several external factors, such as lighting, which might affect a more traditional approach. First the theory and thoughts behind the implementation is presented, followed by an evaluation of the results from physical experiments and the competition itself, ultimately resulting in a robust solution which performed without errors in the competition.
Non-orientable surfaces and electric-magnetic duality
Authors: Wu Siye
Published: October 2018

Abstract

We consider the reduction along two compact directions of a twisted N = 4 gauge theory on a 4-dimensional orientable manifold which is not a global product of two surfaces but contains a non-orientable surface. The low energy theory is a sigma-model on a 2-dimensional worldsheet with a boundary which lives on branes constructed from the Hitchin moduli space of the non-orientable surface. We modify ’t Hooft’s notion of discrete electric and magnetic fluxes in gauge theory due to the breaking of discrete symmetry and we match these fluxes with the homotopy classes of maps in the sigma-model. We verify the mirror symmetry of branes as predicted by S-duality in gauge theory.
The conformal anomaly in bCFT from momentum space perspective
Authors: Prochazka Vladimir
Published: October 2018

Abstract

We study the momentum space representation of energy-momentum tensor two-point functions on a space with a planar boundary in d = 3. We show that non-conservation of momentum in the direction perpendicular to the boundary allows for new phenomena compared to the boundary-less case. Namely we demonstrate how local contact terms arise when the correlators are expanded in the regime where parallel momentum is small compared to the perpendicular one, which corresponds to the near-boundary limit. By exploring two-derivative counterterms involving components of Riemann tensor we identify a finite, scheme-independent part of the two-point function. We then relate this component to the conformal anomaly c
∂ proportional to the boundary curvature

$$ \widehat{R} $$

R
^

. In the formalism of this paper c
∂ arises due to integrating out bulk modes coupled to the curved space, which generate local contributions the effective action at the boundary. To calculate the anomaly in specific (free-field) examples, we combine the method of images with Feynman diagrammatic techniques and propose a general methodology for perturbative computations of this type. The framework is tested by computing c
∂ on the explicit example of free scalar with mixed boundary conditions where we find agreement with the literature.
Black holes in presence of cosmological constant: second order in $$ \frac{1}{D} $$
Authors: Bhattacharyya Sayantani , Biswas Parthajit , Dandekar Yogesh
Published: October 2018

Abstract

We have extended the results of [1] upto second subleading order in an expansion around large dimension D. Unlike the previous case, there are non-trivial metric corrections at this order. Due to our ‘background-covariant’ formalism, the dependence on Ricci and the Riemann curvature tensor of the background is manifest here. The gravity system is dual to a dynamical membrane coupled with a velocity field. The dual membrane is embedded in some smooth background geometry that also satisfies the Einstein equation in presence of cosmological constant. We explicitly computed the corrections to the equation governing the membrane-dynamics. Our results match with earlier derivations in appropriate limits. We calculated the spectrum of QNM from our membrane equations and matched them against similar results derived from gravity.
“We didn't have to go through those barriers”: Culturally affirming learning in a high school affinity group
Authors: Oto Ryan , Chikkatur Anita
Published: October 2018

Using data from interviews, student work, and classroom observations in a “History of Race” course at a private predominantly White high school, this article examines the racialized tensions that led the teacher (first author) to create an unofficial affinity group for students of color that met outside of class. The authors argue that the teacher's attempt to implement a curriculum that was culturally affirming for students of color by de-centering Whiteness led to White students’ resistance that necessitated the creation of an unofficial “safe space” outside of the classroom for the students of color. The need for such a group demonstrates the difficulties inherent in presenting a more honest account of the role of race and racism in the United States that challenges narratives of historical progress. The article concludes that while students of color ideally should have access to culturally affirming knowledge inside social studies classrooms, this experience demonstrates why that kind of knowledge can only be engaged effectively within learning spaces that challenge the norms of conventional social studies education.
InsidePlectosphaerellaceae
Authors: Giraldo A. , Crous P.W.
Published: October 2018

The familyPlectosphaerellaceae(Glomerellales,Sordariomycetes) includes numerous plant pathogenic genera and soil-borne fungal species. Ten genera are currently accepted, including several taxa that occupy an unresolved position within the family. To address this issue, a multilocus sequence analysis was carried out using partial gene sequences from the 28S large subunit nrRNA gene (LSU), the internal transcribed spacer (ITS) regions of the nrDNA region, including the 5.8S nrRNA gene, the translation elongation factor 1-alpha (TEF1-α), tryptophan synthase (TS), actin (ACT) and the RNA polymerase II second largest subunit (RPB2), based on a large set of isolates mainly from the CBS collection. Results of the molecular data combined with a detailed morphological study resolved 22 genera in the family, of which 12 are newly described. Additionally, 15 new species and 10 new combinations are proposed. An epitype and neotype are also introduced forStachylidium bicolorandPlectosphaerella cucumerina, respectively.
Laboratory Insights Into the Effect of Sediment‐Hosted Methane Hydrate Morphology on Elastic Wave Velocity From Time‐Lapse 4‐D Synchrotron X‐Ray Computed Tomography
Authors: Sahoo Sourav K. , Madhusudhan B. N. , Marín‐Moreno Hector , North Laurence J. , Ahmed Sharif , Falcon‐Suarez Ismael Himar , Minshull Tim A. , Best Angus I.
Published: October 2018

A better understanding of the effect of methane hydrate morphology and saturation on elastic wave velocity of hydrate‐bearing sediments is needed for improved seafloor hydrate resource and geohazard assessment. We conducted X‐ray synchrotron time‐lapse 4‐D imaging of methane hydrate evolution in Leighton Buzzard sand and compared the results to analogous hydrate formation and dissociation experiments in Berea sandstone, on which we measured ultrasonic P and S wave velocities and electrical resistivity. The imaging experiment showed that initially hydrate envelops gas bubbles and methane escapes from these bubbles via rupture of hydrate shells, leading to smaller bubbles. This process leads to a transition from pore‐floating to pore‐bridging hydrate morphology. Finally, pore‐bridging hydrate coalesces with that from adjacent pores creating an interpore hydrate framework that interlocks the sand grains. We also observed isolated pockets of gas within hydrate. We observed distinct changes in gradient of P and S wave velocities increase with hydrate saturation. Informed by a theoretical model of idealized hydrate morphology and its influence on elastic wave velocity, we were able to link velocity changes to hydrate morphology progression from initial pore‐floating, then pore‐bridging, to an interpore hydrate framework. The latter observation is the first evidence of this type of hydrate morphology and its measurable effect on velocity. We found anomalously low S wave velocity compared to the effective medium model, probably caused by the presence of a water film between hydrate and mineral grains.
On the Asymmetry Between Upward and Downward Field‐Aligned Currents Interacting With the Ionosphere
Authors: Streltsov A. V.
Published: October 2018

The paper presents results from the numerical study of the magnetosphere‐ionosphere interactions driven by the large‐scale electric field in the magnetically conjugate, high‐latitude regions of northern and southern hemispheres. Simulations of the two‐fluid MHD model demonstrate that these interactions can lead to a generation of a system of small‐scale, intense field‐aligned currents with a significant difference in size and amplitude between the upward and downward currents. In particular, in both hemispheres, the downward currents (where the electrons are flowing from the ionosphere) become more narrow and intense than the adjacent upward currents. At high latitudes, the field‐aligned currents are closely related to the discrete auroral arcs. The fact that this mechanism produces very narrow and intense downward currents embedded into the broader upward current regions makes it relevant to the explanation of the “black” auroral arcs appearing as narrow, dark strips embedded in the broad luminous background.
Empirical Modeling of Dayside Magnetic Structures Associated With Polar Cusps
Authors: Tsyganenko N. A. , Andreeva V. A.
Published: October 2018

The magnetic structure of dayside polar cusps is intimately related to the high‐latitude field‐aligned currents (FACs) and the cross‐B diamagnetic currents due to the penetrated plasma of magnetosheath origin. The dayside FAC configuration is sensitive to the azimuthal component of the interplanetary magnetic field, manifested in the latitudinal splitting and longitudinal overlapping of the Region 1 FAC zone around noon. The diamagnetism of the polar cusp plasma results in deep cleft‐shaped depressions of the ambient magnetic field. Neither of the above factors have yet been properly addressed in the existing empirical models of the distant magnetosphere. To fill this gap, an advanced data‐based model has been developed, including the spiral structure of the dayside FACs and their splitting/overlapping in response to the orientation and magnitude of the azimuthal interplanetary magnetic field component By. The cusp diamagnetic field depressions are modeled using a new approach, based on a 3‐D system of magnetic “bubbles” (Tsyganenko & Andreeva, 2018, https://doi.org/10.1029/2018GL078714). The magnetic effects associated with FACs and diamagnetic currents are represented within the framework of a single hybrid model, fitted to large subsets of spacecraft data. The obtained results are analyzed in the context of the dayside magnetic field response to interplanetary conditions and the geodipole tilt angle.
Current and Future Arctic Aerosols and Ozone From Remote Emissions and Emerging Local Sources—Modeled Source Contributions and Radiative Effects
Authors: Marelle L. , Raut J.‐C. , Law K. S. , Duclaux O.
Published: October 2018

The Arctic is influenced by air pollution transported from lower latitudes, and increasingly by local sources such as shipping and resource extraction. Local Arctic emissions could increase significantly in the future due to industrialization in a warming Arctic and further influence Arctic climate. We use the regional model Weather Research and Forecasting, including chemistry, to investigate current (2012) and future (2050) sources of Arctic aerosol and ozone pollution and their radiative impacts, focusing on spring and summer emissions from midlatitude anthropogenic sources, biomass burning, Arctic shipping, and Arctic gas flaring. Results show that remote anthropogenic and biomass burning emissions are likely to remain the main source of Arctic pollution burdens and of black carbon (BC) deposition over snow, and the main contributors to direct aerosol and ozone radiative effects in the Arctic. However, local Arctic flaring emissions are already a major source of BC in northwestern Russia, with a direct radiative effect of ∼25 mW/m2, and Arctic shipping is a strong current source of aerosols and ozone during summer in the Nordic Seas. We find that the direct effect of ozone and aerosols from summertime Arctic shipping is respectively negative (due to frequent temperature inversions) and positive (because of the high surface albedo) in our simulations, two new results. With the development of diversion shipping through the Arctic Ocean in summer 2050, Arctic shipping emissions could become the main source of surface aerosol and ozone pollution at the surface, with strong associated indirect effects of −0.8 W/m2, while flaring would remain an important BC source.
Seasonal Variations in High Arctic Free Tropospheric Aerosols Over Ny‐Ålesund, Svalbard, Observed by Ground‐Based Lidar
Authors: Shibata T. , Shiraishi K. , Shiobara M. , Iwasaki S. , Takano T.
Published: October 2018

Free tropospheric aerosols over the high Arctic were observed by lidar for about 4 years from March 2014 at Ny‐Ålesund (78.9°N, 11.9°E). Vertical profiles of aerosol backscattering coefficients at two wavelengths, 532 and 1,064 nm, and depolarization ratio at one wavelength, 532 nm, are derived from these observations. The aerosol backscattering coefficient, the particle depolarization ratio, and the color ratio (the ratio of the backscattering coefficients at the two wavelengths) are roughly proportional to mass concentration, nonsphericity, and size of the aerosol particles, respectively. The aerosol backscattering coefficients indicate that monthly averaged concentration of aerosols was largest in the lowest free troposphere at about 1 km in altitude and was an order of magnitude less at an about 10 km in altitude and that the concentration of aerosols was highest from late spring to summer and lowest from late summer to fall. The depolarization ratio was less than a few percent in the troposphere during the four observed years. The depolarization ratio and the color ratio were greatest from winter to spring and smallest from summer to fall. The maxima in the monthly averaged nonsphericity and size precede the maxima in the monthly averaged concentration by a few months, indicating a seasonal change in the morphology or the characteristics of the aerosol particles. The small particle depolarization ratio of less than a few percent is consistent with previous findings that Arctic free tropospheric aerosol particles in spring are composed of a mixture of liquid phase sulfate and soot particles.
Holistic Assessment of SO2 Injections Using CESM1(WACCM): Introduction to the Special Issue
Authors: Kravitz Ben , MacMartin Douglas G. , Tilmes Simone , Richter Jadwiga H. , Mills Michael J. , Lamarque Jean‐Francois , Tribbia Joseph , Large William
Published: October 2018

We introduce a special issue on a holistic assessment of solar geoengineering via stratospheric SO2 injection in the state‐of‐the‐art climate model, Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1(WACCM)). This model has numerous complexities that allow it to represent some of the most important nonlinearities associated with stratospheric SO2 injection, including aerosol microphysical growth and stratospheric chemistry. The studies described herein represent the steps toward and first attempt in a state‐of‐the‐art climate model to use solar geoengineering to meet multiple simultaneous objectives via SO2 injection at multiple locations. First, a set of simulations was carried out to better understand the response of the model to variations in latitude, altitude, and amount of sulfur dioxide injections. Subsequently, in a century‐long simulation, a feedback algorithm was employed to meet specific objectives and manage uncertainty, wherein the injection amount at each location was adjusted every model year. Most of the analyses contained in this special issue focus on surface climate and stratospheric changes in the simulations. In addition, 20 ensemble members of the feedback simulation have been carried out and provided to the community (the Geoengineering Large Ensemble) to expand the scope of analyses to low signal‐to‐noise ratio fields, including regional effects, impacts assessment, and extreme events. The demonstration provided by these simulations is a step toward understanding the space of achievable climate objectives via solar geoengineering or, phrased differently, determining what solar geoengineering can do and what it cannot do.
Cell cycle inhibitors protect motor neurons in an organoid model of Spinal Muscular Atrophy
Authors: Hor Jin Hui , Soh Eunice Shi-Yi , Tan Li Yi , Lim Valerie Jing Wen , Santosa Munirah Mohamad , Winanto  , Ho Beatrice Xuan , Fan Yong , Soh Boon-Seng , Ng Shi-Yan
Published: October 2018

Spinal Muscular Atrophy (SMA) is caused by genetic mutations in the SMN1 gene, resulting in drastically reduced levels of Survival of Motor Neuron (SMN) protein. Although SMN is ubiquitously expressed, spinal motor neurons are one of the most affected cell types. Previous studies have identified pathways uniquely activated in SMA motor neurons, including a hyperactivated ER stress pathway, neuronal hyperexcitability, and defective spliceosomes. To investigate why motor neurons are more affected than other neural types, we developed a spinal organoid model of SMA. We demonstrate overt motor neuron degeneration in SMA spinal organoids, and this degeneration can be prevented using a small molecule inhibitor of CDK4/6, indicating that spinal organoids are an ideal platform for therapeutic discovery.
CD90 determined two subpopulations of glioma-associated mesenchymal stem cells with different roles in tumour progression
Authors: Zhang Qing , Yi Dong-Ye , Xue Bing-Zhou , Wen Wan-Wan , Lu Yin-Ping , Abdelmaksou Ahmed , Sun Min-xuan , Yuan De-tian , Zhao Hong-Yang , Xiong Nan-Xiang , Xiang Wei , Fu Peng
Published: October 2018

Human glioma-associated mesenchymal stem cells (gbMSCs) are the stromal cell components that contribute to the tumourigenesis of malignant gliomas. Recent studies have shown that gbMSCs consist of two distinct subpopulations (CD90+ and CD90− gbMSCs). However, the different roles in glioma progression have not been expounded. In this study, we found that the different roles of gbMSCs in glioma progression were associated with CD90 expression. CD90high gbMSCs significantly drove glioma progression mainly by increasing proliferation, migration and adhesion, where as CD90low gbMSCs contributed to glioma progression chiefly through the transition to pericytes and stimulation of vascular formation via vascular endothelial cells. Furthermore, discrepancies in long non-coding RNAs and mRNAs expression were verified in these two gbMSC subpopulations, and the potential underlying molecular mechanism was discussed. Our data confirm for the first time that CD90high and CD90low gbMSCs play different roles in human glioma progression. These results provide new insights into the possible future use of strategies targeting gbMSC subpopulations in glioma patients.
Genetic patterns in Neotropical Magnolias (Magnoliaceae) using de novo developed microsatellite markers
Authors: Veltjen Emily , Asselman Pieter , Hernández Rodríguez Majela , Palmarola Bejerano Alejandro , Testé Lozano Ernesto , González Torres Luis Roberto , Goetghebeur Paul , Larridon Isabel , Samain Marie-Stéphanie
Published: October 2018

Conserving tree populations safeguards forests since they represent key elements of the ecosystem. The genetic characteristics underlying the evolutionary success of the tree growth form: high genetic diversity, extensive gene flow and strong species integrity, contribute to their survival in terms of adaptability. However, different biological and landscape contexts challenge these characteristics. This study employs 63 de novo developed microsatellite or SSR (Single Sequence Repeat) markers in different datasets of nine Neotropical Magnolia species. The genetic patterns of these protogynous, insect-pollinated tree species occurring in fragmented, highly-disturbed landscapes were investigated. Datasets containing a total of 340 individuals were tested for their genetic structure and degree of inbreeding. Analyses for genetic structure depicted structuring between species, i.e. strong species integrity. Within the species, all but one population pair were considered moderate to highly differentiated, i.e. no indication of extensive gene flow between populations. No overall correlation was observed between genetic and geographic distance of the pairwise species’ populations. In contrast to the pronounced genetic structure, there was no evidence of inbreeding within the populations, suggesting mechanisms favouring cross pollination and/or selection for more genetically diverse, heterozygous offspring. In conclusion, the data illustrate that the Neotropical Magnolias in the context of a fragmented landscape still have ample gene flow within populations, yet little gene flow between populations.
A hybridization-triggered DNAzyme cascade assay for enzyme-free amplified fluorescence detection of nucleic acids
Authors: Wang Huizhen , He Dinggeng , Wu Ri , Cheng Hong , Ma Wenjie , Huang Jin , Bu Hongchang , He Xiaoxiao , Wang Kemin
Published: October 2018

An enzyme-free and ultrasensitive fluorescence assay for the detection of nucleic acids was successfully established by a hybridization-triggered DNAzyme cascade (HTDC).
Enhanced cathode performance of a rGO–V2O5nanocomposite catalyst for microbial fuel cell applications
Authors: Mahalingam Shanmugam , Ayyaru Sivasankaran , Ahn Young-Ho
Published: October 2018

A reduced graphene oxide–V2O5nanocomposite was synthesized by a low temperature surfactant free hydrothermal method and its MFC performance was assessed.
Efficient green photoluminescence and electroluminescence of iridium complexes with high electron mobility
Authors: Han Hua-Bo , Wu Zheng-Guang , Yan Zhi-Ping , Zhao Yue , Zheng You-Xuan
Published: October 2018

Two green iridium complexes with high photoluminescence quantum efficiency were applied in OLEDs showing a maximum current efficiency of 92.76 cd A−1 and a maximum external quantum efficiency of 31.8%, and the efficiency roll-off ratio is low.
Influence of Ni/Mn distributions on the structure and electrochemical properties of Ni-rich cathode materials
Authors: Sun Yiming , Zhang Zhikun , Li Huanhuan , Yang Tao , Zhang Hongzhou , Shi Xixi , Song Dawei , Zhang Lianqi
Published: October 2018

NCM with four type of structures (homogeneous, core–shell, multi-shell and concentration-gradient structures) is synthesized to compare the Ni/Mn distribution influence.
The development, validation, and interpretation of a content coding map for analyzing chemistry lessons in Chinese secondary schools
Authors: Zheng Changlong , Li Langsen , He Peng , Jia Mengying
Published: October 2018

Although the content of science lessons has been analyzed from different perspectives by developing a set of codes (e.g., K. J. Roth, S. L. Druker, H. E. Garnier, M. Lemmens, C. Chen, T. Kawanaka, and R. Gallimore, (2006), Teaching science in five countries: results from the TIMSS 1999 video study, Washington, DC: National Center for Education Statistics), none of the existing coding systems have investigated it from a subject-specific and dynamic perspective. Aiming to fill this gap, this study develops a content coding map (CCM) to classify the content of chemistry lessons (CCL) into 12 types based on their roles and values. The CCM was constructed based on semi-structured interviews and revised by applying the initial CCM to six videotaped lessons. Furthermore, the coding was reviewed by an expert committee to confirm the content validity and evaluated by 86 in-service teachers using a questionnaire with responses measured on a five-point Likert scale to test for face validity. These 12 types of CCL were organized into five related groups in the CCM: core knowledge and practices (CKP), connections among CKP (C-CKP), expansion of CKP (E-CKP), scaffolding for CKP (S-CKP), and meaningless content in relation to CKP (MC-CKP). Each group is illustrated and discussed using specific types of CCL. The CCM, which provides a new way to explore chemistry classrooms, can be used as an analytic tool for chemistry educators to investigate the CCL and can serve as a guide for chemistry teachers when designing lessons.
Construction of an efficient hole migration pathway on hematite for efficient photoelectrochemical water oxidation
Authors: Li Feng , Li Jing , Gao Lili , Hu Yiping , Long Xuefeng , Wei Shenqi , Wang Chenglong , Jin Jun , Ma Jiantai
Published: October 2018

In this study, we constructed an efficient hole migration pathway by integrating ultrathin amorphous NiOOH onto the Fe2O3 coating on F doped α-Fe2O3 nanorods. The resulting photoanode presents higher charge separation efficiency than most reported hematite-based photoanode.
A self-healing Sn anode with an ultra-long cycle life for sodium-ion batteries
Authors: Kim Changhyeon , Kim Icpyo , Kim Huihun , Sadan Milan K. , Yeo Hyewon , Cho Gyubong , Ahn Jaepyoung , Ahn Jouhyeon , Ahn Hyojun
Published: October 2018

Self-healing of a well-designed Sn anode with ultra-long cycle life and stable high capacity.
Nonwoven fabric coated with a tetraphenylethene-based luminescent metal–organic framework for selective and sensitive sensing of nitrobenzene and ammonia
Authors: Tao Chen-Lei , Ying Yan-Mei , Wang Hui , Chen Bin , Zhu Gen-Ping , Song Yan-Jiang , Liu Xun-Gao , Zhao Zujin , Shen Liang , Tang Ben Zhong
Published: October 2018

The photoluminescence of nonwoven fabric coated with a tetraphenylethene-based metal–organic framework can be selectively and sensitively quenched or enhanced by gaseous analytes.
Increasing the breakdown strength of dielectric actuators by using Cu/CuxO/silicone dielectric elastomers
Authors: Duan Lei , Zhang Jie , Zhang Ming , Li Cheng-Hui , Zuo Jing-Lin
Published: October 2018

Cu/CuxO/PDMS films with 15 wt% content of Cu/CuxO exhibited a significantly higher breakdown strength due to the presence of a CuxO layer as the insulating layer, which blocks the formation of conductive networks and reduces the dielectric loss.
Multidimensional signal processing using quaternion complex Hadamard transform in sequency domain
Authors: Jabeen D. , Iqrar T. , Faisal Khan M.
Published: October 2018

This Letter presents the quaternion conjugate symmetric‐sequency ordered complex Hadamard transform (QCS‐SCHT). The purpose of this research is to present the idea of the quaternion in sequency domain that is based on four complexified terms including real and imaginary values are discussed and developed with different types of quaternions planes for QCS‐SCHT. QCS‐SCHT is discussed for colour image processing.
Tuning of a time‐delayed controller for a general class of second‐order linear time invariant systems with dead‐time
Authors: Villafuerte‐Segura Raul , Medina‐Dorantes Francisco , Vite‐Hernández Leopoldo , Aguirre‐Hernández Baltazar
Published: October 2018

In this study, the problem of ‐stabilising a general class of second‐order linear time invariant systems with dead‐time using a proportional–integral–retarded (PIR) controller is considered. The ‐stability of a system determines the exponential decay in its response. Here the ‐stability of the closed‐loop system is ensured by assigning up to four dominant real roots at . For the tuning of the controller gains an extensive analysis of all the possible allocations of the gains according to the response of the closed‐loop system is presented. The D‐partition method is used to provide important insight into the problem. As a consequence of this analysis, to achieve the desired decay rate, exact analytic expressions for tuning the PIR controller parameters are given. To illustrate the theoretical results obtained, the under‐actuated mechanical system called inverted pendulum is used.