bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of IROC and ACDS on‐site audits of reference and non‐reference dosimetry
Authors: Lye Jessica , Kry Stephen , Shaw Maddison , Gibbons Francis , Keehan Stephanie , Lehmann Joerg , Kron Tomas , Followill David , Williams Ivan
Published: September 2019

Purpose

Consistency between different international quality assurance groups is important in the progress toward similar standards and expectations in radiotherapy dosimetry around the world, and in the context of consistent clinical trial data from international trial participants. This study compares the dosimetry audit methodology and results of two international quality assurance groups performing a side‐by‐side comparison at the same radiotherapy department, and interrogates the ability of the audits to detect deliberately introduced errors.

Methods

A comparison of the core dosimetry components of reference and non‐reference audits was conducted by the Imaging and Radiation Oncology Core (IROC, Houston, USA) and the Australian Clinical Dosimetry Service (ACDS, Melbourne, Australia). A set of measurements were conducted over 2 days at an Australian radiation therapy facility in Melbourne. Each group evaluated the reference dosimetry, output factors, small field output factors, percentage depth dose (PDD), wedge, and off‐axis factors according to their standard protocols. IROC additionally investigated the Electron PDD and the ACDS investigated the effect of heterogeneities. In order to evaluate and compare the performance of these audits under suboptimal conditions, artificial errors in percentage depth dose (PDD), EDW, and small field output factors were introduced into the 6 MV beam model to simulate potential commissioning/modeling errors and both audits were tested for their sensitivity in detecting these errors.

Results

With the plans from the clinical beam model, almost all results were within tolerance and at an optimal pass level. Good consistency was found between the two audits as almost all findings were consistent between them. Only two results were different between the results of IROC and the ACDS. The measurements of reference FFF photons showed a discrepancy of 0.7% between ACDS and IROC due to the inclusion of a 0.5% nonuniformity correction by the ACDS. The second difference between IROC and the ACDS was seen with the lung phantom. The asymmetric field behind lung measured by the ACDS was slightly (0.3%) above the ACDS's pass (optimal) level of 3.3%. IROC did not detect this issue because their measurements were all assessed in a homogeneous phantom. When errors were deliberately introduced neither audit was sensitive enough to pick up a 2% change to the small field output factors. The introduced PDD change was flagged by both audits. Similarly, the introduced error of using 25° wedge instead of 30° wedge was detectible in both audits as out of tolerance.

Conclusions

Despite different equipment, approach, and scope of measurements in on‐site audits, there were clear similarities between the results from the two groups. This finding is encouraging in the context of a global harmonized approach to radiotherapy quality assurance and dosimetry audit.
Effect of source blur on digital breast tomosynthesis reconstruction
Authors: Zheng Jiabei , Fessler Jeffrey A. , Chan Heang‐Ping
Published: September 2019

Purpose

Most digital breast tomosynthesis (DBT) reconstruction methods neglect the blurring of the projection views caused by the finite size or motion of the x‐ray focal spot. This paper studies the effect of source blur on the spatial resolution of reconstructed DBT using analytical calculation and simulation, and compares the influence of source blur over a range of blurred source sizes.

Methods

Mathematically derived formulas describe the point spread function (PSF) of source blur on the detector plane as a function of the spatial locations of the finite‐sized source and the object. By using the available technical parameters of some clinical DBT systems, we estimated the effective source sizes over a range of exposure time and DBT scan geometries. We used the CatSim simulation tool (GE Global Research, NY) to generate digital phantoms containing line pairs and beads at different locations and imaged with sources of four different sizes covering the range of potential source blur. By analyzing the relative contrasts of the test objects in the reconstructed images, we studied the effect of the source blur on the spatial resolution of DBT. Furthermore, we simulated a detector that rotated in synchrony with the source about the rotation center and calculated the spatial distribution of the blurring distance in the imaged volume to estimate its influence on source blur.

Results

Calculations demonstrate that the PSF is highly shift‐variant, making it challenging to accurately implement during reconstruction. The results of the simulated phantoms demonstrated that a typical finite‐sized focal spot (~0.3 mm) will not affect the reconstructed image resolution if the x‐ray tube is stationary during data acquisition. If the x‐ray tube moves during exposure, the extra blur due to the source motion may degrade image resolution, depending on the effective size of the source along the direction of the motion. A detector that rotates in synchrony with the source does not reduce the influence of source blur substantially.

Conclusions

This study demonstrates that the extra source blur due to the motion of the x‐ray tube during image acquisition substantially degrades the reconstructed image resolution. This effect cannot be alleviated by rotating the detector in synchrony with the source. The simulation results suggest that there are potential benefits of modeling the source blur in image reconstruction for DBT systems using continuous‐motion acquisition mode.
Image reconstruction for positron emission tomography based on patch‐based regularization and dictionary learning
Authors: Zhang Wanhong , Gao Juan , Yang Yongfeng , Liang Dong , Liu Xin , Zheng Hairong , Hu Zhanli
Published: September 2019

Purpose

Positron emission tomography (PET) is an important tool for nuclear medical imaging. It has been widely used in clinical diagnosis, scientific research, and drug testing. PET is a kind of emission computed tomography. Its basic imaging principle is to use the positron annihilation radiation generated by radionuclide decay to generate gamma photon images. However, in practical applications, due to the low gamma photon counting rate, limited acquisition time, inconsistent detector characteristics, and electronic noise, measured PET projection data often contain considerable noise, which results in ill‐conditioned PET images. Therefore, determining how to obtain high‐quality reconstructed PET images suitable for clinical applications is a valuable research topic. In this context, this paper presents an image reconstruction algorithm based on patch‐based regularization and dictionary learning (DL) called the patch‐DL algorithm. Compared to other algorithms, the proposed algorithm can retain more image details while suppressing noise.

Methods

Expectation‐maximization (EM)‐like image updating, image smoothing, pixel‐by‐pixel image fusion, and DL are the four steps of the proposed reconstruction algorithm. We used a two‐dimensional (2D) brain phantom to evaluate the proposed algorithm by simulating sinograms that contained random Poisson noise. We also quantitatively compared the patch‐DL algorithm with a pixel‐based algorithm, a patch‐based algorithm, and an adaptive dictionary learning (AD) algorithm.

Results

Through computer simulations, we demonstrated the advantages of the patch‐DL method over the pixel‐, patch‐, and AD‐based methods in terms of the tradeoff between noise suppression and detail retention in reconstructed images. Quantitative analysis shows that the proposed method results in a better performance statistically [according to the mean absolute error (MAE), correlation coefficient (CORR), and root mean square error (RMSE)] in considered region of interests (ROI) with two simulated count levels. Additionally, to analyze whether the results among these methods have significant differences, we used one‐way analysis of variance (ANOVA) to calculate the corresponding P values. The results show that most of the P < 0.01; some P> 0.01 < 0.05. Therefore, our method can achieve a better quantitative performance than those of traditional methods.

Conclusions

The results show that the proposed algorithm has the potential to improve the quality of PET image reconstruction. Since the proposed algorithm was validated only with simulated 2D data, it still needs to be further validated with real three‐dimensional data. In the future, we intend to explore GPU parallelization technology to further improve the computational efficiency and shorten the computation time.
Pelvic floor muscle displacement during jumps in continent and incontinent women: An exploratory study
Authors: Moser Helene , Leitner Monika , Eichelberger Patric , Kuhn Annette , Baeyens Jean‐Pierre , Radlinger Lorenz
Published: September 2019

Introduction

The prevalence of stress urinary incontinence during high‐impact activities is high. Enhanced comprehension of pelvic floor muscle (PFM) displacement and activity is clinically relevant for the development of specific approaches in rehabilitation.

The aim of the study is to investigate and to compare PFM displacement between the continent and incontinent women during jumps.

Methods

A cross‐sectional, exploratory design was applied to investigate PFM displacement during drop jumps (DJ) and countermovement jumps (CMJ). PFM displacement was assessed in craniocaudal translation and forward‐backward rotation with an electromagnetic tracking system.

Results

Twenty‐eight continent and 22 incontinent women were included. During the first landing of DJ, a primary caudal, during the second landing of DJ/CMJ a primary cranial translation and during all jump a primary backward rotation was observed. No significant difference between the groups was found.

Discussion

PFM displacement during running demonstrated caudal translation/forward rotation before and cranial translation/backward rotation after heel strike. During the second landing of DJ/CMJ a cranial translation/backward rotation and during the first landing of DJ a caudal translation/backward rotation has been observed after ground contact. This may be due to the longer lasting bodyweight force in the first landing of DJ. No eccentric‐concentric stretch‐shortening cycle could be seen.

Conclusion

This study indicates that during jumps two opposite reactions of involuntary PFM displacement happen, but no stretch‐shortening cycle with an eccentric‐concentric contraction could be found. Jumping stimuli inducing involuntary PFM displacement should be used for future investigations to consider a beneficial effect concerning continence.
Observation of Squeeze–Twist Coupling in a Chiral 3D Isotropic Lattice
Authors: Li Jianheng , Ha Chan Soo , Lakes Roderic S.
Published: September 2019

A chiral 3D lattice is designed, made by 3D printing, and studied experimentally. The lattice exhibits squeeze–twist coupling and a Poisson's ratio near zero. Squeeze–twist coupling does not occur in classical elasticity which makes no provision for chirality. By contrast, chiral effects are allowed in Cosserat elasticity. An experimental squeeze–twist coupling strain ratio on the order of unity and a Poisson's ratio near zero are in reasonable agreement with prior finite element analysis of a lattice with similar structure, for which negative Poisson's ratio is anticipated for a sufficient number of cells.
Challenges in Sr2FeMoO6−δ Thin Film Deposition
Authors: Suchaneck Gunnar , Kalanda Nikolay , Artsiukh Evgenij , Gerlach Gerald
Published: September 2019

This work reviews some fundamental issues that are relevant for the fabrication of stable‐phase strontium ferromolybdate thin films. The main challenges for strontium ferromolybdate thin film deposition arise from the sensitivity of the material's magnetic properties to point defect formation: i) Antisite defect formation and oxygen nonstoichiometry should be avoided by precise composition control during film manufacturing; ii) a highly ordered state of the correct phase and B‐site cation valence will be obtained only in a very narrow window of growth conditions; iii) to avoid additional antisite disorder with decreasing synthesis temperature, the effective temperature at the film surface should be increased by an energy flux to the growing film surface. Since thin film deposition is nonequilibrium in nature, the review starts with the consideration of equilibrium phase stability. Cation and oxygen stoichiometries are analyzed with regard to their effect on key magnetic properties. Film strain formed due to thermal and lattice mismatch is of great concern since it influences the choice of the substrate. Finally, thin film deposition techniques are valued for their benefits in strontium ferromolybdate thin film technology.
Alternating Current‐Driven Oxide Powder Electroluminescent Device Employing Vertically Aligned ZnO Nanowire Array
Authors: Ma Siwei , Tan Sirui , Kitai Adrian H.
Published: September 2019

A novel type of AC‐driven oxide powder electroluminescent (EL) device is demonstrated. The device is based on stable heterogeneous junctions between Mn2+‐activated zinc germanate (Zn2GeO4:Mn) oxide phosphor and a vertically aligned ZnO nanowire array. The ZnO nanowire array is synthesized on an ITO‐coated glass substrate via a hydrothermal growth method. A stable phosphor–nanowire junction is formed by simple drop‐coating of a Zn2GeO4:Mn oxide phosphor suspension on the nanowire layer followed by annealing at 400 °C for 3 h. Bright green light (≈20 cd m−2) with a wavelength of 535 nm from the as‐fabricated EL device is observed, and the as‐fabricated device shows excellent stability in air, maintaining a brightness of ≈10 cd m−2 for 15 days with less than 2.5% intensity loss. The electroluminescence emission mechanism is discussed in detail. This new and facile strategy to build an oxide powder EL device can enable cost‐effective, highly stable, and energy‐efficient devices for lighting or display applications.
Dopant‐Free Hole Transporting Molecules for Highly Efficient Perovskite Photovoltaic with Strong Interfacial Interaction
Authors: Meng Fanxu , Jia Yu , Wang Jiantao , Huang Xiaoyu , Gui Zhigang , Huang Li , Li Ruxue , Chen Rui , Xu Jing , Chen Wei , He Zhubing , Hsu Hsien-Yi , Zhu Enwei , Che Guangbo , Wang Hsing-Lin
Published: September 2019

One of the attractive ways to develop efficient and cost‐effective inverted perovskite solar cells (PVSCs) is through the use of dopant‐free hole transporting materials (HTMs) with facile synthesis and a lower price tag. Herein, two organic small molecules with a fluorene core are presented as dopant‐free HTMs in inverted PVSCs, namely, FB‐OMeTPA and FT‐OMeTPA. The two molecules are designed in such a way they differ by replacing one of the benzene rings (FB‐OMeTPA) with thiophene (FT‐OMeTPA), which leads to a significantly improved coplanarity as manifested in the redshift of the absorbance and a smaller bandgap energy. Density functional theory calculations show that FT‐OMeTPA has a strong Pb2+–S interaction at the FT‐OMeTPA/perovskite interface, allowing surface passivation and facilitating charge transfer across interfaces. As a result, the PVSCs based on FT‐OMeTPA exhibit a much higher hole mobility, power conversion efficiency, operational stability, and less hysteresis as compared with devices based on FB‐OMeTPA.
MoS2 Quantum Dots Modified Black Ti3+–TiO2/g‐C3N4 Hollow Nanosphere Heterojunction toward Photocatalytic Hydrogen Production Enhancement
Authors: Pan Jiaqi , Dong Zongjun , Jiang Ziyuan , Zhao Chuang , Wang Beibei , Zhao Weijie , Wang Jingjing , Song Changsheng , Zheng Yingying , Li Chaorong
Published: September 2019

The MoS2 quantum dots (QDs) modified black Ti3+–TiO2/g‐C3N4 hollow nanosphere heterojunction is synthesized via the continuous chemical template deposition and sculpture–reduction processes. The results of structural characterizations imply that the Ti3+–TiO2/g‐C3N4/MoS2 QDs hollow nanosphere heterojunction is prepared successfully. The photocatalytic hydrogen evolution reaction (HER) of the B‐TiO2/g‐C3N4/MoS2 QDs (≈1524.37 μmol g−1 h−1) exhibits an enhancement of ≈33 folds compared with the normal TiO2. Furthermore, the process of photocatalysis and the mechanism of photocatalytic HER enhancement are explored, which can be ascribed to the HER activity sites of MoS2 QDs, Ti3+/Ov ions in the Ti3+–TiO2, and hollow nanosphere heterojunction, which are proved by electrochemical measurements.
Effective Microstructure Unit in Control of Plasticity during Strain‐Controlled Fracture
Authors: Long Shao-lei , Liang Yi-long , Lin Min , Yang Ming , Yin Cun-hong , Long Qiong
Published: September 2019

Strain‐controlled fracture is investigated in 20CrNi2Mo steel using the Hall–Petch relationship, electron backscatter diffraction (EBSD), and other techniques. An interesting result is that the ductility of the tested steel increases with a coarsening of prior austenite grains. This finding is in contrast to conventional understanding. Meanwhile, the strain after necking is approximately 2/3 of the total strain, and the value of UC (crack propagation energy per unit volume) reaches 95% of UK (static toughness). The ductility of 20CrNi2Mo steel also depends on crack propagation. Furthermore, the Hall–Petch relationships between ductility and multilevel microstructure demonstrate that lath is the effective control unit of the plasticity of the tested steel. Lath also plays a key role in crack propagation that results from the rotating, bending, and shearing of lath, as confirmed by fracture analysis and EBSD.
Synaptic vesicle fusion is modulated through feedback inhibition by dopamine auto‐receptors
Authors: Formisano Rosaria , Mersha Mahlet D. , Caplan Jeff , Singh Abhyudai , Rankin Catharine H. , Tavernarakis Nektarios , Dhillon Harbinder S.
Published: September 2019

Mechanisms of synaptic vesicular fusion and neurotransmitter clearance are highly controlled processes whose finely‐tuned regulation is critical for neural function. This modulation has been suggested to involve pre‐synaptic auto‐receptors; however, their underlying mechanisms of action remain unclear. Previous studies with the well‐defined C. elegans nervous system have used functional imaging to implicate acid sensing ion channels (ASIC‐1) to describe synaptic vesicle fusion dynamics within its eight dopaminergic neurons. Implementing a similar imaging approach with a pH‐sensitive fluorescent reporter and fluorescence resonance after photobleaching (FRAP), we analyzed dynamic imaging data collected from individual synaptic termini in live animals. We present evidence that constitutive fusion of neurotransmitter vesicles on dopaminergic synaptic termini is modulated through DOP‐2 auto‐receptors via a negative feedback loop. Integrating our previous results showing the role of ASIC‐1 in a positive feedback loop, we also put forth an updated model for synaptic vesicle fusion in which, along with DAT‐1 and ASIC‐1, the dopamine auto‐receptor DOP‐2 lies at a modulatory hub at dopaminergic synapses. Our findings are of potential broader significance as similar mechanisms are likely to be used by auto‐receptors for other small molecule neurotransmitters across species.
The Ĥ-parameter: an oblique Higgs view
Authors: Englert Christoph , Giudice Gian F. , Greljo Admir , McCullough Matthew
Published: September 2019

Abstract

We study, from theoretical and phenomenological angles, the Higgs boson oblique parameter Ĥ, as the hallmark of off-shell Higgs physics. Ĥ is defined as the Wilson coefficient of the sole dimension-6 operator that modifies the Higgs boson propagator, within a Universal EFT. Theoretically, we describe self-consistency conditions on Wilson coefficients, derived from the Källén-Lehmann representation. Phenomenologically, we demonstrate that the process gg → h
∗ → V V is insensitive to propagator corrections from Ĥ, and instead advertise four-top production as an effective high-energy probe of off-shell Higgs behaviour, crucial to break flat directions in the EFT.
Leptogenesis in Δ(27) with a universal texture zero
Authors: Björkeroth Fredrik , de Medeiros Varzielas Ivo , López-Ibáñez M. L. , Melis Aurora , Vives Óscar
Published: September 2019

Abstract

We investigate the possibility of viable leptogenesis in an appealing Δ(27) model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both N
1 and N
2 right-handed neutrino decays. The N
1-dominated scenario is successful and the most natural option for the model, with M
1 ∈ [109
, 1012] GeV, and M
1
/M
2 ∈ [0.002, 0.1], which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the N
2-dominated scenario, with the asymmetry in the electron flavour protected from N
1 washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy M
1
/M
2
< 0.002, and M
2 relatively close to M
3, which is not a natural expectation of the Δ(27) model.
Stress and cognitive biases in schizotypy: A two-site study of bias
against disconfirmatory evidence and jumping to conclusions
Authors: Le Thanh P. , Fedechko Taylor L. , Cohen Alex S. , Allred Samantha , Pham Carrie , Lewis Shôn , Barkus Emma
Published: September 2019

The dysfunctional cognitive and reasoning biases which underpin
psychotic symptoms are likely to present prior to the onset of a diagnosable
disorder and should therefore be detectable along the psychosis continuum in
individuals with schizotypal traits. Two reasoning biases, Bias Against
Disconfirmatory Evidence (BADE) and Jumping to Conclusions (JTC), describe
how information is selected and weighed under conditions of uncertainty
during decision making. It is likely that states such as elevated stress
exacerbates JTC and BADE in individuals with high schizotypal traits
vulnerable to displaying these information gathering styles. Therefore, we
evaluated whether stress and schizotypy interacted to predict these
reasoning biases using separate samples from the US (JTC) and England
(BADE). Generally speaking, schizotypal traits and stress were not
independently associated with dysfunctional reasoning biases. However,
across both studies, the interaction between schizotypy traits and stress
significantly predicted reasoning biases such that increased stress was
associated with increased reasoning biases, but only for individuals low in
schizotypal traits. These patterns were observed for positive schizotypal
traits (in both samples), for negative traits (in the England sample only),
but not for disorganization traits. For both samples, our findings suggest
that the presence of states such as stress is associated with, though not
necessarily dysfunctional, reasoning biases in individuals with low
schizotypy. These reasoning biases seemed, in some ways, relatively
immutable to stress in individuals endorsing high levels of positive
schizotypal traits.
Light Permeates Seasonally Through Arctic Sea Ice
Authors: Kornei Katherine
Published: September 2019

The transmission of sunlight through Arctic sea ice depends on the presence of ice, snow, and melt ponds, data collected over 6 years reveal.
Volcanic Eruption Creates Temporary Islands of Pumice
Authors: Kornei Katherine
Published: September 2019

Rafts of pumice, spewed from an undersea volcano, recently appeared in the South Pacific. These transient, movable islands are important toeholds for marine life like barnacles, coral, and macroalgae.
Rapid Expansion and Evolution of a Regional Dust Storm in the Acidalia Corridor During the Initial Growth Phase of the Martian Global Dust Storm of 2018
Authors: Shirley J. H. , Kleinböhl A. , Kass D. M. , Steele L. J. , Heavens N. G. , Suzuki S. , Piqueux S. , Schofield J. T. , McCleese D. J.
Published: September 2019

A vigorous regional dust storm substantially altered both the global atmospheric thermal structure and the magnitude and spatial distribution of dust loading within the Mars atmosphere between 1 and 9 June 2018. We examine the development and decay of this storm in latitude, longitude, altitude, and time, employing observations by the Mars Climate Sounder on board the Mars Reconnaissance Orbiter. Dust layer top altitudes rose from seasonal‐normal values of ~40 to ~70 km. Dust lofting to high altitudes was localized between 0° and ~60°W longitude, and between 60°N and 60°S latitude. Intensification of paired meridional overturning circulation cells within the study area is confirmed by strong nighttime dynamical heating in higher latitudes of both hemispheres. By the end of this episode, significant dust loading was present at altitudes greater than 50 km above all longitudes on Mars, and other dust lifting centers had been activated.
Precipitation of MeV and Sub‐MeV Electrons Due to Combined Effects of EMIC and ULF Waves
Authors: Zhang X.‐J. , Mourenas D. , Artemyev A. V. , Angelopoulos V. , Sauvaud J.‐A.
Published: September 2019

We explore the mechanism of MeV and sub‐MeV electron precipitations into the atmosphere in the outer radiation belt, through quasi‐linear pitch‐angle scattering by electromagnetic ion cyclotron (EMIC) waves, when strong compressional Pc4–Pc5 ultralow‐frequency (ULF) waves are simultaneously present. Theoretically, the opposite magnetic field and density modulations produced by such ULF waves can significantly reduce the minimum electron energy for cyclotron resonance with EMIC waves, and this could potentially lead to the loss of lower energy (MeV and sub‐MeV) electrons. Statistical satellite observations of simultaneous, intense EMIC and ULF waves reveal the parameter domains most conducive to such lower energy electron losses, which are shown to be mostly located near the geosynchronous orbit. Selected events further suggest that such a mechanism could be efficient in the outer radiation belt and that even larger effects might occur during strong injections from the plasma sheet.
High‐Frequency Plasma Waves and Pitch Angle Scattering Induced by Pulsed Electron Beams
Authors: Delzanno G. L. , Roytershteyn V.
Published: September 2019

Cherenkov radiation from a pulse of charge propagating along the magnetic field in a magnetized plasma is analyzed using theory and fluid‐kinetic simulations. Besides radiation into whistler modes, the subject of many previous investigations in laboratory and space, radiation can occur through extraordinary (X) modes. Theory and simulations demonstrate that X mode radiation efficiencies can be orders of magnitude higher than those into whistler modes. Test particle simulations of the dynamics of energetic electrons in the beam‐generated wavefield show that X modes can also induce pitch angle scattering much more efficiently than whistlers. While coherence effects associated with spreading of realistic beam pulses may limit the size of the X mode source region, a simple model of beam dynamics suggests that the size of this region could be substantial (hundreds of meters for ionospheric conditions). These results have potentially important implications for many problems, including understanding losses in the near‐Earth environment and radiation belt remediation.
Changes in the Impact of the Autumn Tibetan Plateau Snow Cover on the Winter Temperature Over North America in the mid‐1990s
Authors: Qian QiFeng , Jia XiaoJing , Wu Renguang
Published: September 2019

This study investigates the changes in the impact of the interannual variation of autumn snow cover over the eastern Tibetan Plateau (TP; ASCETP) on winter surface air temperature (SAT) over North America (NA) in the mid‐1990s using both observational data and a linear baroclinic numerical model. The index of ASCETP shows an abrupt change with a predominant negative phase before and a predominant positive phase after 1994; thus, the analysis is performed for two subperiods: 1979–1994 (P1) and 1995–2014 (P2). An ASCETP‐related energy budget analysis shows that the ASCETP variation has a more pronounced cooling effect on the above atmosphere in P1 than in P2. The snow‐related anomalous negative geopotential height above the TP is more pronounced and extends farther northeastward in P1 than in P2. Further analysis shows that the relationship between the ASCETP and NA winter SAT is not steady. During P1, associated with an anomalous positive ASCETP, negative geopotential height anomalies emerge over the northeastern TP. These negative anomalies impose an anomalous vorticity perturbation near the East Asian westerly jet core that propagates eastward, forming a wave train‐like pattern. It crosses the North Pacific Ocean and reaches the NA region, leading to positive and negative winter SAT anomalies over western and eastern NA, respectively. In contrast, during P2, the impact of anomalous ASCETP on the variation in the winter SAT over NA is weak, probably due to the relatively weak local cooling effect of the ASCETP and the weak ASCETP‐related vorticity forcing around the East Asian westerly jet.
Size‐Resolved Characterization of the Chromophores in Atmospheric Particulate Matter From a Typical Coal‐Burning City in China
Authors: Chen Qingcai , Mu Zhen , Song Wenhuai , Wang Yuqin , Yang Zhaohong , Zhang Lixin , Zhang Yan‐Lin
Published: September 2019

This study reports the size‐resolved characterization of the chromophores in atmospheric particulate matter in Linfen, a typical coal‐burning city in China. The optical properties of both the water‐soluble and water‐insoluble chromophores in atmospheric particulates are studied using excitation‐emission matrix spectroscopy and follow the parallel factor analysis of excitation‐emission matrix data. The mass absorption efficiency and normalized fluorescence volume by mass concentration of the organic carbon in methanol‐soluble matter in the particulate samples are stronger than that of the water‐soluble matter. We found that the total absorption (Abs), fluorescence volume (FV), mass absorption efficiency, and normalized fluorescence volume of particle extracts with sizes less than 10 μm increased with the decreasing particle size. The total concentration of the selected seven polycyclic aromatic hydrocarbons was positively correlated with the Abs365 and FV of both the water‐soluble matter and methanol‐soluble matter, but the average contribution of the selected polycyclic aromatic hydrocarbons to the total Abs and FV was very small (<3%). This study is the first to report a size‐resolved characterization of the chromophores in atmospheric particulate matter. Humic‐like substances tend to be present in small particles, and tryptophan‐like and tyrosine‐like components tend to increase with increasing particle size.
Scalable integration of nano-, and microfluidics with hybrid two-photon lithography
Authors: Vanderpoorten Oliver , Peter Quentin , Challa Pavan K. , Keyser Ulrich F. , Baumberg Jeremy , Kaminski Clemens F. , Knowles Tuomas P. J.
Published: September 2019

Nanofluidic devices have great potential for applications in areas ranging from renewable energy to human health. A crucial requirement for the successful operation of nanofluidic devices is the ability to interface them in a scalable manner with the outside world. Here, we demonstrate a hybrid two photon nanolithography approach interfaced with conventional mask whole-wafer UV-photolithography to generate master wafers for the fabrication of integrated micro and nanofluidic devices. Using this approach we demonstrate the fabrication of molds from SU-8 photoresist with nanofluidic features down to 230 nm lateral width and channel heights from micron to sub-100 nm. Scanning electron microscopy and atomic force microscopy were used to characterize the printing capabilities of the system and show the integration of nanofluidic channels into an existing microfluidic chip design. The functionality of the devices was demonstrated through super-resolution microscopy, allowing the observation of features below the diffraction limit of light produced using our approach. Single molecule localization of diffusing dye molecules verified the successful imprint of nanochannels and the spatial confinement of molecules to 200 nm across the nanochannel molded from the master wafer. This approach integrates readily with current microfluidic fabrication methods and allows the combination of microfluidic devices with locally two-photon-written nano-sized functionalities, enabling rapid nanofluidic device fabrication and enhancement of existing microfluidic device architectures with nanofluidic features.
Simple and customizable method for fabrication of high-aspect ratio microneedle molds using low-cost 3D printing
Authors: Krieger Kevin J. , Bertollo Nicky , Dangol Manita , Sheridan John T. , Lowery Madeleine M. , O’Cearbhaill Eoin D.
Published: September 2019

We present a simple and customizable microneedle mold fabrication technique using a low-cost desktop SLA 3D printer. As opposed to conventional microneedle fabrication methods, this technique neither requires complex and expensive manufacturing facilities nor expertise in microfabrication. While most low-cost 3D-printed microneedles to date display low aspect ratios and poor tip sharpness, we show that by introducing a two-step “Print & Fill” mold fabrication method, it is possible to obtain high-aspect ratio sharp needles that are capable of penetrating tissue. Studying first the effect of varying design input parameters and print settings, it is shown that printed needles are always shorter than specified. With decreasing input height, needles also begin displaying an increasingly greater than specified needle base diameter. Both factors contribute to low aspect ratio needles when attempting to print sub-millimeter height needles. By setting input height tall enough, it is possible to print needles with high-aspect ratios and tip radii of 20–40 µm. This tip sharpness is smaller than the specified printer resolution. Consequently, high-aspect ratio sharp needle arrays are printed in basins which are backfilled and cured in a second step, leaving sub-millimeter microneedles exposed resulting microneedle arrays which can be used as male masters. Silicone female master molds are then formed from the fabricated microneedle arrays. Using the molds, both carboxymethyl cellulose loaded with rhodamine B as well as polylactic acid microneedle arrays are produced and their quality examined. A skin insertion study is performed to demonstrate the functional capabilities of arrays made from the fabricated molds. This method can be easily adopted by the microneedle research community for in-house master mold fabrication and parametric optimization of microneedle arrays.
A self-assembled graphene nanomask for the epitaxial growth of nonplanar and planar GaN
Authors: Xu Yu , Cao Bing , Li Zongyao , Zheng Shunan , Cai Demin , Wang Mingyue , Zhang Yumin , Wang Jianfeng , Wang Chinhua , Xu Ke
Published: September 2019

Herein, we demonstrated the fabrication of architectural GaN nanostructures by the self-assembly NSAG (SNSAG) technology using multilayer graphene (MLG) as a nanomask.
Molecular dynamics simulation of thermo-mechanical behaviour of elastomer cross-linked via multifunctional zwitterions
Authors: Athir Naveed , Shi Ling , Shah Sayyed Asim Ali , Zhang Zhiyu , Cheng Jue , Liu Jun , Zhang Junying
Published: September 2019

Coarse-grained (CG) molecular dynamics simulations have been employed to study the thermo-mechanical response of a physically cross-linked network composed of zwitterionic moieties and fully flexible elastomeric polymer chains.
Core-dependent properties of copper nanoclusters: valence-pure nanoclusters as NIR TADF emitters and mixed-valence ones as semiconductors
Authors: Zhang Leon Li-Min , Zhou Guodong , Zhou Guoqing , Lee Hung-Kay , Zhao Ni , Prezhdo Oleg V. , Mak Thomas C. W.
Published: September 2019

While valence-pure copper alkynyl nanoclusters show near-infrared TADF, the mixed-valence ones exhibit semiconductivity.
Orientational instability and spontaneous rotation of active nematic droplets
Authors: Morozov Matvey , Michelin Sébastien
Published: September 2019

Orientational instability of the nematic configuration in active nematic microdrops may result in a helical motion of the drop.
“Induced-Fit Suction” effect: a booster for biofuel storage and separation
Authors: Li He , Guo Fangyuan , Hu Jun , Peng Changjun , Wang Hualin , Liu Honglai , Li Jing
Published: September 2019

An “Induced-Fit Suction” effect was proposed by fine-tuning the amphiphilicity of ZIF-7 and facilitated the selective adsorption of n-butanol from aqueous solution through structural deformation.
An Hα kinematic survey of the Herschel Reference Survey
Authors: Gómez-López J. A. , Amram P. , Epinat B. , Boselli A. , Rosado M. , Marcelin M. , Boissier S. , Gach J.-L. , Sánchez-Cruces M. , Sardaneta M. M.
Published: September 2019

Aims. We present new 2D high resolution Fabry–Perot spectroscopic observations of 152 star-forming galaxies that are part of the Herschel Reference Survey (HRS), which is a complete K-band selected, volume-limited sample of nearby galaxies that spans a wide range of stellar mass and morphological types.

Methods. By using improved data reduction techniques, that provide adaptive binning based on Voronoi tessellation, and using large field-of-view observations, we derived high spectral resolution (R >  10 000) Hα datacubes from which we computed Hα maps and radial 2D velocity fields that are based on several of thousand independent measurements. A robust method based on such fields allowed us to accurately compute rotation curves and kinematical parameters, for which uncertainties are calculated using a method based on the power spectrum of the residual velocity fields.

Results. We checked the consistency of the rotation curves by comparing our maximum rotational velocities to those derived from H I data, and by computing the i-band, NIR, stellar, and baryonic Tully-Fisher relations. We used this set of kinematical data combined with those available at other frequencies to study, for the first time, the relation between the dynamical and the total baryonic mass (stars, atomic and molecular gas, metals, and dust) and to derive the baryonic and dynamical main sequence on a representative sample of the local universe.
Transitioning from Practice to Health Care Administration: The Later Years
Authors: Opelka Frank G.
Published: September 2019

Since the late 1800s, the role of the physician has evolved substantially beyond mainstream clinical medicine. As fee for service models expanded in the 1980s, resulting in an unsustainable financial crisis in health care, senior physicians stepped up to provide essential input and expertise to administrators on a national level. This model of physician–administrator has evolved to include dual-degree physicians who are equipped with specialized knowledge even at the outset of their career. As physicians are now vital members of health care administration, many will feel the need to transition from clinical practice to a new position where they can effect change on a larger scale. This article will provide insight into such transitions and dual-career pathways and discuss important considerations when faced with this juncture in one's career.
Relationship of Mandibular Ramus Dimensions to Lower Third Molar Impaction
Authors: Al-Gunaid Talat Hasan , Bukhari Abdul Kadir , El Khateeb Sara M. , Yamaki Masaki
Published: September 2019

Objectives The aim of this study was to investigate the mandibular ramus features that could contribute to the etiology of mandibular third molar impaction.

Materials and Methods Two hundred and forty subjects were divided into two groups: impacted group: 115 subjects presented with an impacted mandibular third
molar, and control group: 125 subjects with the normal mandibular third molar eruption. Digital panoramic radiographs were used, and four angular and twelve linear
measurements were done. Comparisons between groups were done using Student's t-test. Pearson correlation and linear regression tests were used to assess the degree of
relationship between retromolar space and mandibular measurements.

Results Control group showed significant greater measurements in most of the variables, whereas the impacted group showed significant larger gonial angle and larger inclination of lower posterior teeth than the control group. Significant correlations were found between retromolar space and coronoid height, ramal heights, ramus notch depths, the inclination of lower posterior teeth, and retromolar space/3M width ratio in both groups.

Conclusion The present study found that the configuration of the mandibular ramus appears to be discrete in many aspects in the erupted other than impacted lower third molars subjects, which might be a possible cause for the impaction.
Effects of Rapid Maxillary Expansion and Facemask Therapy on the Soft Tissue Profiles of Class III Patients at Different Growth Stages
Authors: Ozzeybek Can Fatma Selen , Turkkahraman Hakan
Published: September 2019

Objectives The aim of this study was to evaluate the effects of rapid maxillary expansion (RME) and facemask therapy on the soft tissue profiles of class III patients at different growth stages.

Materials and Methods Forty-five subjects (23 females and 22 males) were divided into prepubertal, pubertal, and postpubertal groups. Bonded type RME appliances and Petit-type facemasks were fitted to each patient, and intraoral elastics were applied from the hooks of the RME appliance to the facemask.

Statistical Analysis All measurements were statistically analyzed with SPSS version 18.0 (SPSS Inc., Chicago, IL, United States) for Windows. Repeated-measures of ANOVA and posthoc Tukey tests were used to compare the groups.

Results The soft tissue nasion, pronasale, subnasale, soft tissue A point, and labrale superior landmarks were all displaced forward and downward, and the most dramatic changes were recorded in the pubertal group. The labrale inferior, soft tissue B point, soft tissue pogonion, and soft tissue menton landmarks moved backward and downward in all groups, and the greatest displacements were observed in the pubertal group.

Conclusions The soft tissue profiles improved significantly and became more convex in all treatment groups. Although, the most favorable facial changes were observed in the pubertal growth stage, the treatments applied in the postpubertal stage also elicited significant changes and should thus be considered viable treatment options.
Efficacy of a Copper–Calcium–Hydroxide Solution in Reducing Microbial Plaque on Orthodontic Clear Aligners: A Case Report
Authors: Meto Aida , Colombari Bruna , Castagnoli Anna , Sarti Mario , Denti Lucia , Blasi Elisabetta
Published: September 2019

The aim of this study was to investigate the ability of a copper–calcium–hydroxide-based compound to remove microbial plaque naturally produced onto orthodontic clear aligners. A commercially available dental paste, named Cupral, based on copper–calcium–hydroxide, was used. A healthy volunteer (female, 32 years old), undergoing orthodontic treatment with thermoplastic clear aligners was enrolled. By conventional/confocal microscopy and colony-forming unit (CFU) assay, 2-week used aligners were examined for microbial plaque, prior and following exposure to Cupral. Confocal microscopy revealed abundant plaque irregularly distributed onto the aligner surface. Following Cupral treatment, a drastic decrease occurred in plaque thickness and matrix presence. As assessed by the CFU assay, total microbial load approached 109 CFUs/aligner, with slight differences in aerobiosis and anaerobiosis culture conditions; six macroscopically different types of colonies were detected and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Following Cupral treatment, microbial load dropped to undetectable levels, irrespectively of the conditions considered. Exposure of clear aligners to Cupral results in the elimination of contaminating microorganisms; the antimicrobial activity is retained up to 1.25% concentration. Overall, our data describe a novel use of Cupral, a copper–calcium–hydroxide-based compound, in daily hygiene practices with promising results.
Incorporation of Vanadium and Molybdenum into Yttrium-Arsenotungstates Supported by Amino Acid Ligands
Authors: Bagherjeri Fateme Akhlaghi , Ritchie Chris , Gable Robert W. , Bryant Gary , Boskovic Colette
Published: September 2019

The preference for incorporation of molybdenum over tungsten into specific sites of a family of yttrium-arsenotungstates with amino acid ligands prompted exploration of the incorporation of other metals, affording three new vanadium-containing (V/W and V/Mo/W) analogues: K2(GlyH)10[As4(V2W2)W44Y4O160(Gly)8(H2O)12]·11Gly (1), (MBAH)9(L-NleH)3[As4(V2W2)W44Y4O160(L-Nle)8(H2O)12] (2), and (MBAH)9(L-NleH)3[As4(V2W2)Mo2W42Y4O160(L-Nle)8(H2O)12] (3) (Gly=glycine and L-Nle=l-norleucine, MBAH=4-methylbenzylammonium). These hybrid polyoxometalates all possess a tetrametallic oxo-bridged {VIV2WVI2} central core surrounded by an amino acid-ligated cyclic metal-oxo framework. X-Ray photoelectron, UV-visible reflectance, and electron paramagnetic resonance spectroscopy, together with metal analysis, confirm the incorporation of vanadium into the polyoxometalates, while single crystal X-ray diffraction analysis supports the location of the vanadium atoms in the central core.
Antimony(III) induces fibroblast-like phenotype, profibrotic factors and reactive oxygen species in mouse renal cells
Authors: Roldán Nicole , Pizarro Danitza , Verdugo Marcelo , Salinas-Parra Nicolas , Quiroz Waldo , Reyes-Martinez Cristian , Figueroa Stefanny , Quiroz Carolina , Gonzalez Alexis A.
Published: September 2019

Environmental contextAntimony is a metalloid occurring at overall low concentrations in the Earth’s crust. Owing to anthropogenic activities, however, antimony can be found at elevated and detrimental levels in some environments. We report eco-toxicological effects of antimony in biological models, results from which can help predict antimony’s ecological and environmental impact. AbstractThe aim of this work was to evaluate the effect of SbIII on cell integrity, expression of profibrotic factors and reactive oxygen species (ROS) in mouse cortical collecting duct cells (M-1 cell line). M-1 cells were incubated with SbIII for 24h. Cell morphology and RNA expression level (connecting tissue growth factor, CTGF), α-SMOOTH MUSCLE ACTIN (α-SMA) and collagen I were analysed. The total Sb content according to each cell compartment was determined and ROS production was measured. Eighty percent of the total Sb was detected in the extracellular medium. A significant increase in ROS production and CTGF protein expression were observed at 100μgL−1 SbIII. M-1 cells showed a non-classic epithelial cell shape at 100μgL−1 and a reduction in the collecting duct-specific marker aquaporin-2. At 100μgL−1, the number of collagen I-positive cells increased. At 300μgL−1, a gross cell nuclear rupture was observed. These results demonstrate that an SbIII concentration of 100μgL−1 is able to promote the induction of CTGF and collagen I along with the induction of ROS, which suggests a cytotoxicity of SbIII in M-1 kidney collecting duct cells.