bluuebunny/crossref_metadata_2025 huggingface dataset:
A High‐Performance and Long‐Term Air‐Stable CH3NH3PbI3/C8BTBT Heterojunction Photodetector Fabricated via Chemical Vapor Deposition
Authors: Li Xing , Xie Pengshan , Mo Xindi , Xiang Yang , Xiao Zhixing , Xiongsong Tengxiao , Huang Han , Sun Jia , Dai Guozhang , Yang Junliang
Published: December 2020

Organic–inorganic hybrid perovskites are considered as a class of star materials for optoelectronic devices. However, the stability is one of the big issues. Herein, an MAPbI3 perovskite film with high stability is fabricated using chemical vapor deposition (CVD). The stability and performance of the MAPbI3 photodetector are further improved by constructing an MAPbI3 heterojunction with the organic semiconductor C8BTBT. The MAPbI3/C8BTBT heterojunction photodetector shows a wide spectral response range from ultraviolet to visible light and a fast response time of 30 ms/12 ms. Under laser irradiation at 405 nm, the responsivity of the MAPbI3/C8BTBT heterojunction photodetector reaches 6.09 A W−1, which is an 11.9‐fold improvement as compared with the MAPbI3 photodetector (0.51 A W−1). After storage under ambient conditions (humidity of ≈35%) for 2 months, the MAPbI3/C8BTBT heterojunction photodetector still exhibits excellent stability and the photocurrent maintains 93.7% of its initially measured value. The excellent stability under ambient conditions is likely the result of the stable MAPbI3 film that is fabricated via CVD and the protection of the organic semiconductor layer C8BTBT. The results provide a feasible route toward high‐performance and stable perovskite optoelectronic devices by combining CVD with perovskite heterojunctions.
Modelling and parametrization of the convective flow over leads in sea ice and comparison with airborne observations
Authors: Michaelis Janosch , Lüpkes Christof , Schmitt Amelie U. , Hartmann Jörg
Published: December 2020

A non‐eddy‐resolving microscale model is applied to simulate convection over three different leads (elongated channels in sea ice), which were observed by aircraft over the Arctic Marginal Ice Zone in 2013. The study aims to evaluate the quality of a local and a non‐local turbulence parametrization. The latter represents a lead‐width‐dependent approach for the turbulent fluxes designed for idealised conditions of a lead‐perpendicular, near‐neutral inflow in an atmospheric boundary layer (ABL) capped by a strong inversion at around 250 to 350 m height. The observed cases considered here are also characterised by an almost lead‐perpendicular flow but, in comparison to the idealised conditions, our analysis covers effects in stable inflow conditions and a much shallower ABL. The model simulations are initialised with observed surface parameters and upwind profiles, and the results are compared with measurements obtained above and downwind of the leads. The basic observed features related to the lead‐generated convection can be reproduced with both closures, but the observed plume inclination and vertical entrainment near the inversion layer by the penetrating plume are underestimated. The advantage of the non‐local closure becomes obvious by the more realistic representation of regions with observed vertical entrainment or where the observations hint at counter‐gradient transport. It is shown by comparison with the observations that results obtained with the non‐local closure can be further improved by including the determination of a fetch‐dependent inversion height and by specifying a parameter determining the plume inclination as a function of the upwind ABL stratification. Both effects improve the representation of fluxes, boundary‐layer warming, and vertical entrainment. The model is also able to reproduce the observed vanishing of a weak low‐level jet over the lead, but its downwind regeneration and related momentum transport are not always well captured, irrespective of the closure used.
Methylenecyclopropylglycine and hypoglycin A intoxication in three Pére David's Deers (Elaphurus davidianus) with atypical myopathy
Authors: Bochnia Mandy , Ziemssen Eva , Sander Johannes , Stief Birgit , Zeyner Annette
Published: December 2020

Background

Hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG) from seeds/seedlings of Sycamore maple (SM, Acer pseudoplatanus) causes atypical myopathy (AM) in horses. AM was not known to occur in wild ruminants until several fatalities in milus (Elaphurus davidianus) following the ingestion of HGA in SM seeds. However, a role for MCPrG has not previously been evaluated.

Objectives

To test the hypothesis that MCPrG is also a major factor in AM in milus, three milus (M1, M2, M3) from the Zoo Dresden (aged 7–11 years, 2 females and 1 male, in good nutritional condition) that developed AM were studied.

Methods

Serum, urine and methanol extracts from the liver, kidney, rumen digesta and faeces were analysed by ultrahigh‐performance liquid chromatography‐tandem mass spectrometry for HGA, MCPrG and for conjugates of carnitine (C) and glycine (G): Methylenecyclopropylacetyl (MCPA)‐G, MCPA‐C, Methylenecyclopropylformyl (MCPF)‐G, MCPF‐C, butyryl‐C and isobutyryl‐C.

Results

HGA in serum was high (M2 480 nmol/L; M3 460 nmol/L), but MCPrG was not. HGA and MCPrG were found in rumen and faeces extracts, and MCPrG was also identified in the liver. Metabolites of HGA and MCPrG were high in serum, urine and liver, but not in the rumen or faeces.

Conclusions

This study shows that MCPrG is involved in the pathophysiology of AM in milus. The metabolism of MCPrG is considered to be faster because, after ingestion, the specific metabolites appear highly concentrated in the serum. The high toxin concentration in the liver suggests that a possible transfer into products for human consumption may pose a risk.
Transportation is critical to reducing greenhouse gas emissions in the United States
Authors: Bleviss Deborah L.
Published: December 2020

In the last 4 years, the transportation sector has overtaken the power sector as the major source of greenhouse gas (GHG) emissions, and it is expected to continue to be the dominant sector for emissions into the future. In contrast to the power sector, transportation faces substantially more challenges to reducing GHG emissions. This article will examine those barriers and then review three major strategies to reduce emissions in this sector. They include: (a) substantially improve the fuel economy of the passenger light vehicle fleet; (b) advance the usage of emerging alternatively‐fueled light vehicles, particularly electric vehicles, while reducing their GHG emissions; and (c) invest in and modernize public transportation to increase its use substantially.

This article is categorized under:

Energy and Transport > Economics and Policy

Energy and Climate > Climate and Environment

Energy Policy and Planning > Climate and Environment
Teaching Sexual History Taking in Health Care Using Online Technology: A PLISSIT-Plus Zoom Approach During the Coronavirus Disease 2019 Shutdown
Authors: Ross Michael W. , Newstrom Nicholas , Coleman Eli
Published: December 2020

Aim

Cancellation of university classes during the coronavirus disease 2019 pandemic challenges teaching inperson sexual history–taking skills to medical, physician assistant, and nursing students. We used commercial online electronic services for medical students to learn sexual history–taking skills.

Methods

A total of 174 medical students viewed a lecture on sexual history taking and the PLISSIT model (Permission, Limited Information, Specific Suggestion, Intensive Therapy) and were then randomized into dyads. They arranged a time to meet online on Zoom with their partner, chose a simple sexual history case-history (male or female) from a small selection, and recorded the 5- to 6-minute sexual history within a 1-week time frame. Each student played a “provider” or “patient” and then switched roles with a new case. One of the course tutors, all sexual health practitioners, downloaded 10 videos randomly assigned to them asynchronously and viewed and commented on the interaction of each “provider” along with comments on what to improve in the sexual history. 2 weeks later after the remainder of the lectures in the course, a second, more complex set of 8 cases were provided, so students could move at their comfort pace and choose 1.

Main Outcome Measure

Students were required to make 1 online post and 1 comment on another student's post for each case, on the experience, and associated issues arising, positive or negative. All comments were downloaded and analyzed by theme.

Results

Major themes included developing comfort in using sexual language, using simpler sexual terms suitable for patients, feeling confidence and mastery, excitement using technology developing clinical skills, surprise watching their performances and body language, observation of how they appeared to the “patient,” organizing sexual histories and incorporating PLISSIT model, ability to ask about context and relationships, and seeing the exercise as building on existing clinical skills training. Some expressed anxiety and nervousness, which by the second case had largely or completely dissipated.

Conclusion

A readily replicable, secure, cheap cloud-based model to integrate sexual history training asynchronously was provided, with tutors’ comments, and student skills development, and performance evaluated.
Adding Supra-Aortic Trunk Surgical Reconstruction to Carotid Endarterectomy: Implications on Risk of Stroke and Death
Authors: Goudreau Bernadette J. , Wang Linda J. , Latz Christopher A. , Conrad Mark F. , Williams Carlin A. , Tracci Margaret C. , Kern John A. , Clouse Darrin W
Published: December 2020

BACKGROUND:

Additive risks of combining supra-aortic trunk surgical reconstruction (SAT) with carotid endarterectomy (CEA) for associated carotid bifurcation and great vessel disease management are not well defined. This study sought to define risk of combining SAT with CEA.

STUDY DESIGN:

Isolated CEA (ICEA) and CEA+SAT (from 2005 to 2015) were identified from NSQIP, excluding nonocclusive indications. CEA+SAT were compared with ICEA as well as a propensity-matched ICEA cohort. Primary outcomes included 30-day stroke, death, and composite (SD). Outcomes were then weighted by symptomatic status. Univariate and logistic regression analyses were performed.

RESULTS:

Patients included 79,477 ICEA and 270 CEA+SAT. SAT reconstructions included 19 (7%) aorto-carotid bypasses, 21 (8%) carotid-subclavian transpositions, 85 (31%) carotid-carotid bypasses, and 145 (54%) carotid-subclavian bypasses. There was no difference in 30-day mortality (vs CEA+SAT 1.5% vs ICEA 0.7% p = 0.12). CEA+SAT had higher rates of stroke (3.7% vs 1.6%, p = 0.005) and stroke and death (SD) (4.8% vs 2.1%, p = 0.001). Predictors of SD included CEA+SAT (odds ratio [OR] 5.2, 95% CI 1.03–26.3, p = 0.046) and symptomatic status (OR 1.9, 95% CI 1.1–3.2, p = 0.02). After propensity matching, CEA+SAT continued to have higher rates of stroke (3.4% vs 0.4%, p = 0.01) and SD (4.5% vs 1.5%, p = 0.04), with similar mortality (1.5% vs 1.1%, p = 0.70). No differences were noted in primary endpoints in asymptomatic patients. In symptomatic patients, CEA+SAT carried significantly higher stroke (5.6% vs 2.1%, p = 0.04) and SD risk (7.0% vs 2.8%, p = 0.03).

CONCLUSIONS:

CEA+SAT confers increased risk of stroke and SD over ICEA. Symptomatic status and concomitant procedure contribute to this risk. Management should be considered within the context of lesion characteristics, patient longevity, and individual operative risk profile.
Confocal photoluminescence characterization of silicon-vacancy color centers in 4H-SiC fabricated by a femtosecond laser
Authors: Liu Jiayu , Xu Zongwei , Song Ying , Wang Hong , Dong Bing , Li Shaobei , Ren Jia , Li Qiang , Rommel Mathias , Gu Xinhua , Liu Bowen , Hu Minglie , Fang Fengzhou
Published: December 2020

Silicon-vacancy (VSi) centers in silicon carbide (SiC) are expected to serve as solid qubits, which can be used in quantum computing and sensing. As a new controllable color center fabrication method, femtosecond (fs) laser writing has been gradually applied in the preparation of VSi in SiC. In this study, 4H-SiC was directly written by an fs laser and characterized at 293 K by atomic force microscopy, confocal photoluminescence (PL), and Raman spectroscopy. PL signals of VSi were found and analyzed using 785 nm laser excitation by means of depth profiling and two-dimensional mapping. The influence of machining parameters on the VSi formation was analyzed, and the three-dimensional distribution of VSi defects in the fs laser writing of 4H-SiC was established.
The Alaska Convergent Margin Backstop Splay Fault Zone, a Potential Large Tsunami Generator Between the Frontal Prism and Continental Framework
Authors: von Huene Roland , Miller John J. , Krabbenhoeft Anne
Published: December 2020

The giant tsunami that swept the Pacific from Alaska to Antarctica in 1946 was generated along one of three Alaska Trench instrumentally recorded aftershock areas following great and giant earthquakes. Aftershock areas were investigated during the past decade with multibeam bathymetry, ocean bottom seismograph wide‐angle seismic, reprocessed legacy, and new seismic reflection images. Summarized and updated here are previous papers and additional data. Tectonic structures collocated with aftershock area boundaries indicate possible lengths of rupture in future great earthquakes. NE aftershock area boundaries relate to subducted lower plate structures whereas the SW zone upper plate retains Beringian structural relicts. The lower to middle slope transition separating a stronger continental framework rock from a weaker accreted prism occurs along splay fault zones previously interpreted as backstops in seismic images. Damage zones along splay faults are generally 1‐km‐wide dipping typically 21°. Splays form slip paths from the plate interface to the seafloor much shorter than the 3–4° dipping plate interface beneath the frontal prism. Associated seafloor vent structures indicate overpressured fluids at depth. Splay fault dip and its rigid hanging wall impart greater seafloor uplift than the accreted prism per unit of slip making them effective tsunami generators. Backstop splay fault zones (BSFZs) run along the entire Alaska Trench. Beneath the frontal prism, active bend faults add rugosity to the plate interface and km high relief is commonly imaged in reprocessed legacy and new seismic data. The 1946 Unimak great (M8.6) earthquake epicenter is located near the BSFZ.
Phytoplankton “Missing” Absorption in Marine Waters: A Novel Pigment Compensation Model for the Packaging Effect
Authors: Huan Yu , Sun Deyong , Wang Shengqiang , Bilal Muhammad , Zhang Hailong , Qiu Zhongfeng , He Yijun
Published: December 2020

The packaging effect (Qa*) of phytoplankton pigments can account for over half of the variability in the phytoplankton absorption coefficient (aph) in oceanic waters. Given the significance of aph in many marine biogeochemical and environmental processes, exploring the packaging effect on absorption properties is a crucial task. In the present study, two pigment compensation models for quantifying the packaging effect are developed for Case I and Case II waters using high‐performance liquid chromatography (HPLC) derived pigments and aph data. The Case I model is based on data from the NOMAD data set from the Atlantic Ocean, and the Case II model is based on data taken in the marginal seas of China. Phytoplankton “missing” absorption is derived by subtracting the reconstructed aph without the packaging effect from the measured aph. Our proposed models use the established relationships between “missing” absorption and specific absorption coefficients of pigment groups without the packaging effect to quantify pigment group concentrations. Validation using independent in situ data sets demonstrates that significant improvements are achieved to quantify the packaging effect, especially for waters under abnormal packaging effect conditions (Qa* > 1), where the mean ratio of normal Qa* increasing largest from 40% to 90% in 455 nm in Case I water and from 70% to 100% in 520 nm in Case II water. Applying the proposed models to satellite data displays the spatial distributions of the packaging effect in the Atlantic Ocean and the marginal seas of China, as delegates of Case I and II waters, respectively. The Qa* intensity negatively covaries with the chlorophyll‐a distribution. This study shows the spatial variability of the packaging effect from satellite observations for the first time.
Interannual‐to‐Decadal Variations of Particulate Organic Carbon and the Contribution of Phytoplankton in the Tropical Pacific During 1981–2016: A Model Study
Authors: Yu Jun , Wang Xiujun , Murtugudde Raghu , Tian Feng , Zhang Rong‐Hua
Published: December 2020

The tropical Pacific plays an important role in the global carbon cycle. However, little is known on the large‐scale variability of particulate organic carbon (POC) and the contribution of phytoplankton carbon (PhyC) in this region. Here, we used a basin‐scale model to study the spatio‐temporal variability of POC and PhyC contribution over 1981–2016 in the tropical Pacific. The model reproduces the spatial and temporal variability of the observed POC in this region. Both satellite and modeled POC show a clear west‐to‐east increase (from 40 to 60 mg m−3) in the equatorial Pacific. The contribution of PhyC to POC is greater in the iron‐limited eastern region (∼30%) than in the nitrogen‐limited western region (∼20%). There are strong interannual variabilities in both POC and the contribution of PhyC to POC, which are largely associated with the El Niño–Southern Oscillation (ENSO) events. POC stock and downward flux show significant increases (10%–20%) in the frontal region (near the dateline) but smaller changes in the eastern equatorial Pacific post‐1998, due to the Pacific Decadal Oscillation (PDO) regime shift. There were significant increases (∼5–10% to the west and ∼5% to the east) in the transfer efficiency of POC across the basin during 1999–2014 due to the PDO regime shift. This study highlights the impacts of iron and nitrogen co‐limitations on phytoplankton dynamics and physical forcing on the carbon cycle of the tropical Pacific, with implications for the global carbon cycle.
Observations and Modeling of Ocean Circulation in the Seychelles Plateau Region
Authors: Castillo‐Trujillo Alma Carolina , Arzeno‐Soltero Isabella B. , Giddings Sarah N. , Pawlak Geno , McClean Julie , Rainville Luc
Published: December 2020

The ocean circulation around and over the Seychelles Plateau (SP) is characterized using 35 months of temperature and velocity measurements along with a numerical model. The results here provide the first documented description of the ocean circulation atop the SP. The SP is an unusually broad (∼200 km), shallow (∼50 m) plateau, dropping off steeply to the abyss. It is situated in a dynamic location (3.5–5.5°S, 54‐57°E) in the south‐western tropical Indian Ocean where northwesterly winds are present during austral summer and become southeasterly in austral winter, following the reversal of the western Indian ocean monsoon winds. Measurements around the Inner Islands, on the SP, have been carried out since 2015. Velocity measurements show that most of the depth‐averaged current variance on the SP arises from near‐inertial oscillations and lower‐frequency variability. Lower‐frequency variability encompasses seasonal and intraseasonal variability, the latter of which includes the effects of mixed Rossby‐gravity waves and mesoscale eddies. A global 0.1° numerical ocean simulation is used in conjunction with these observations to describe the regional circulation around the SP. Atop the SP, circulation is dominated by ageostrophic processes consistent with Ekman dynamics, while around the SP, both geostrophic and ageostrophic processes are important and vary seasonally. Stratification responds to the sea surface height semiannual signal which is due to Ekman pumping‐driven upwelling (related to the Seychelles‐Chagos Thermocline Ridge) and the arrival of an annual downwelling Rossby wave.
Global Ocean Wind‐Wave Model Hindcasts Forced by Different Reanalyzes: A Comparative Assessment
Authors: Sharmar V. D. , Markina M. Yu. , Gulev S. K.
Published: December 2020

Four global wind wave hindcasts based on the third‐generation spectral wave model WAVEWATCH III forced by ERA5, ERA‐Interim, National Centers of Environmental Prediction and Climate Forecast System Reanalysis (CFSR) and MERRA2 reanalyzes for 1980–2019 are presented. Absolute magnitudes of both 10‐m wind speeds and significant wave heights are the largest in the CFSR and CFSR‐based hindcast respectively, particularly in the extratropical regions. The differences in annual extremes between CFSR and ERA5 (and corresponding hindcasts) amount to 2.4 ms−1 for wind speeds and 1.2 m for wave heights. CFSR and CFSR‐based hindcast also stand out with respect to remaining datasets, showing mostly negative trends in both mean and extreme characteristics. ERA5‐, ERA‐Interim‐, and MERRA2‐based hindcasts show annual positive trends in wave heights in 1980–2019, in particular in the Southern Ocean (up to 0.15 m decade‐1 for extreme wave heights in MERRA2‐based hindcast) as well as in the central Pacific, equatorial and tropical Atlantic, and Indian Oceans. All four hindcasts agree on the positive linear trends in the North Atlantic midlatitudes and subtropics, western South Atlantic midlatitudes and the tropical South Pacific, and the negative trends in the eastern North Pacific midlatitudes. Areas with significant linear trends in wave heights generally coincide with those for wind speeds, however, they have larger spatial coverage. The interannual variability in significant wave heights is the most consistent across different hindcasts in the eastern midlatitudes of both hemispheres. The performed hindcasts provide a useful background for studies on both present and future wave climates.
Simulation of the Present and Future Projection of Permafrost on the Qinghai‐Tibet Plateau with Statistical and Machine Learning Models
Authors: Ni Jie , Wu Tonghua , Zhu Xiaofan , Hu Guojie , Zou Defu , Wu Xiaodong , Li Ren , Xie Changwei , Qiao Yongping , Pang Qiangqiang , Hao Junming , Yang Cheng
Published: December 2020

The comprehensive understanding of the occurred changes of permafrost, including the changes of mean annual ground temperature (MAGT) and active layer thickness (ALT), on the Qinghai‐Tibet Plateau (QTP) is critical to project permafrost changes due to climate change. Here, we use statistical and machine learning (ML) modeling approaches to simulate the present and future changes of MAGT and ALT in the permafrost regions of the QTP. The results show that the combination of statistical and ML method is reliable to simulate the MAGT and ALT, with the root‐mean‐square error of 0.53°C and 0.69 m for the MAGT and ALT, respectively. The results show that the present (2000–2015) permafrost area on the QTP is 1.04 × 106 km2 (0.80–1.28 × 106 km2), and the average MAGT and ALT are −1.35 ± 0.42°C and 2.3 ± 0.60 m, respectively. According to the classification system of permafrost stability, 37.3% of the QTP permafrost is suffering from the risk of disappearance. In the future (2061–2080), the near‐surface permafrost area will shrink significantly under different Representative Concentration Pathway scenarios (RCPs). It is predicted that the permafrost area will be reduced to 42% of the present area under RCP8.5. Overall, the future changes of MAGT and ALT are pronounced and region‐specific. As a result, the combined statistical method with ML requires less parameters and input variables for simulation permafrost thermal regimes and could present an efficient way to figure out the response of permafrost to climatic changes on the QTP.
Validation of SAGE III/ISS Solar Water Vapor Data With Correlative Satellite and Balloon‐Borne Measurements
Authors: Davis S. M. , Damadeo R. , Flittner D. , Rosenlof K. H. , Park M. , Randel W. J. , Hall E. G. , Huber D. , Hurst D. F. , Jordan A. F. , Kizer S. , Millan L. F. , Selkirk H. , Taha G. , Walker K. A. , Vömel H.
Published: December 2020

Since June 2017, the Stratospheric Aerosol and Gas Experiment III instrument on the International Space Station (SAGE III/ISS) has been providing vertical profiles of upper tropospheric to stratospheric water vapor (SWV) retrieved from solar occultation transmission measurements. The goal of this study is to evaluate the publicly released SAGE III/ISS beta version 5.1 WV retrieval through intercomparison with independent satellite‐ and balloon‐based measurements, and to present recommendations for SAGE III/ISS data quality screening criteria. Overall, we find that SAGE III/ISS provides high quality water vapor measurements. Low quality profiles are predominately due to retrieval instabilities in the upper stratosphere that cause step‐like changes in the profile, and aerosol/cloud‐related interferences (below ∼20 km). Above 35 km, the retrieved uncertainty and noise in the data rapidly grow with increasing altitude due to relatively low extinction signal from water vapor. Below the tropopause, retrieved uncertainty increases with decreasing altitude due to enhanced molecular scattering and aerosol extinction. After screening low‐quality data using the procedures described herein, SAGE III/ISS WV is shown to be in good agreement with independent satellite and balloon‐based measurements. From 20 to 40 km, SAGE III/ISS WV v5.1 data exhibit a bias of 0.0 to −0.5 ppmv (∼10%) relative to the independent data, depending on the instrument and altitude. Despite its status as a beta version, the level of SAGE III/ISS WV agreement with independent data is similar to previous SAGE instruments, and therefore the data are suitable for scientific studies of SWV.
The Effect of Pressure and Mg‐Content on Ilmenite Rheology: Implications for Lunar Cumulate Mantle Overturn
Authors: Tokle Leif , Hirth Greg , Liang Yan , Raterron Paul , Dygert Nick
Published: December 2020

The viscosity of ilmenite is an important parameter that is thought to have influenced the thermal and chemical evolution of the lunar cumulate mantle. We conduct deformation experiments on two different ilmenite compositions, ilmenite100 (FeTiO3) and ilmenite40 ((Fe0.4Mg0.6)TiO3), to investigate the influence of pressure and Mg‐content on the rheology of ilmenite aggregates. Experiments were conducted in a Griggs apparatus and a deformation‐DIA apparatus at pressures spanning 1–5 GPa. Using the new experimental data and reanalyzed data from Dygert et al. (2016), we determine pressure‐dependent flow law parameters for ilmenite100 (A = 2.183 MPa−ns−1, n = 3.0 ± 0.4, E = 276 ± 25 kJ/mol and V = 17 ± 4 cm3/mol) and ilmenite40 (A = 3.936e−7 MPa−ns−1, n = 5.7 ± 0.5, E = 283 ± 25 kJ/mol and V = 26 ± 4 cm3/mol). Over the range of experimental conditions ilmenite40 has a larger stress exponent and activation volume than ilmenite100. Extrapolation of the ilmenite100 flow law predicts a viscosity approximately five orders of magnitude lower than dry olivine and three orders of magnitude lower than wet olivine at a temperature of 1,100°C, pressure of 0.3 GPa, and stress of 0.3 MPa, conditions representative of the early ilmenite‐bearing cumulate. Our estimated viscosity contrasts for a dry lunar mantle suggests that lunar cumulate mantle overturn may be dominated by longer wavelength downwellings, while a wet lunar mantle may be dominated by shorter wavelength downwellings.
Simulation of Seismic Wave Propagation on Asteroid Ryugu Induced by The Impact Experiment of The Hayabusa2 Mission: Limited Mass Transport by Low Yield Strength of Porous Regolith
Authors: Nishiyama G. , Kawamura T. , Namiki N. , Fernando B. , Leng K. , Onodera K. , Sugita S. , Saiki T. , Imamura H. , Takagi Y. , Yano H. , Hayakawa M. , Okamoto C. , Sawada H. , Tsuda Y. , Ogawa K. , Nakazawa S. , Iijima Y.
Published: December 2020

Seismic shaking has been regarded as an essential source of resurfacing on asteroids. The Small Carry‐on Impactor (SCI) operation on Hayabusa2 has been expected to be a unique opportunity for testing in situ seismic shaking whose energy is sufficiently large to excite observable surface modification. However, no obvious regolith hopping was identified even immediately outside of the crater formed by the SCI impact. To understand this discrepancy from the expectation, we simulate seismic wave propagation on Ryugu with a wide range of surface material properties and evaluate maximum acceleration on the surface. Numerical results reveal that low‐quality factor or low seismic efficiency is required to explain the lack of geomorphological change after the SCI experiment. Considering that scattering under anhydrous conditions cannot efficiently dissipate energy, such a low‐quality factor is not plausible. The weak yield strength in porous materials can efficiently decrease seismic wave energies, making the apparent seismic efficiency extremely low. Based on this hypothesis, we propose a formulation of surface mobility on asteroids that considers the physical properties of regolith. We consistently estimate the occurrence of seismic shaking with the existence of unstable boulders on Ryugu.
Radiation Data Portal: Integration of Radiation Measurements at the Aviation Altitudes and Solar‐Terrestrial Environment Observations
Authors: Sadykov V. M. , Kitiashvili I. N. , Tobiska W. K. , Guhathakurta M.
Published: December 2020

The impact of radiation dramatically increases at high altitudes in the Earth's atmosphere and in space. Therefore, monitoring and access to radiation environment measurements are critical for estimating the radiation exposure risks of aircraft and spacecraft crews and the impact of space weather disturbances on electronics. Addressing these needs requires convenient access to multisource radiation environment data and enhancement of visualization and search capabilities. The Radiation Data Portal represents an interactive web‐based application for search and visualization of in‐flight radiation measurements. The portal enhances the exploration capabilities of various properties of the radiation environment and provides measurements of dose rates along with information on space weather‐related conditions. The Radiation Data Portal back‐end is a MySQL relational database that contains the radiation measurements obtained from the Automated Radiation Measurements for Aerospace Safety (ARMAS) device and the soft X‐ray and proton flux measurements from the Geostationary Operational Environmental Satellite. The implemented application programming interface and Python routines allow a user to retrieve the database records without interaction with the web interface. As a use case of the Radiation Data Portal, we examine ARMAS measurements during an enhancement of the solar proton (SP) fluxes, known as solar proton events, and compare them to measurements during SP‐quiet periods.
Aorto-Right Atrial Fistula after Minimally Invasive Tricuspid Valve Repair: A Report of Two Cases
Authors: Ishidou Kouhei , Hirofuji Aina , Wakabayashi Naohiro , Kamiya Hiroyuki
Published: December 2020

We experienced two cases of postoperative iatrogenic aorto-right atrial fistula (ARAF) after tricuspid valve repair (TVR) using minimally invasive cardiac surgery (MICS) technique. In both the cases, the flow of ARAF passed through the sinus of Valsalva near the noncoronary cusp (NCC)/right coronary cusp (RCC) commissure or NCC to right atrium. The quality of the fine needle used in the MICS technique may be inferior to that used in conventional surgery; ARAF after TVR could be a unique pitfall with the MICS technique.
Basic Reproduction Number of Enterovirus 71 and Coxsackievirus A16 and A6: Evidence From Outbreaks of Hand, Foot, and Mouth Disease in China Between 2011 and 2018
Authors: Zhang Zhong , Liu Yang , Liu Fengfeng , Ren Minrui , Nie Taoran , Cui Jinzhao , Chang Zhaorui , Li Zhongjie
Published: December 2020

Background

Enterovirus 71 (EV-A71), coxsackievirus A16 (CV-A16), and coxsackievirus A6 (CV-A6) are common serotypes causing hand, foot, and mouth disease (HFMD). Analyses on the basic reproduction number (R0) of common pathogens causing HFMD are limited and there are no related studies using field data from outbreaks in mainland China.

Methods

We estimated the pathogen-specific basic reproduction number based on laboratory-confirmed HFMD outbreaks (clusters of ≥10 HFMD cases) reported to the national surveillance system between 2011 and 2018. The reproduction numbers were calculated using a mathematical model and the cumulative cases during the initial growth periods.

Results

This study included 539 outbreaks, of which 198 were caused by EV-A71, 316 by CV-A16, and 25 by CV-A6. All 10 417 cases involved were children. Assuming the outbreaks occurred in closed systems and the incubation period is 5 days, the median (interquartile range [IQR]) R0 estimates of EV-A71, CV-A16, and CV-A6 were 5.06 (2.81, 10.20), 4.84 (3.00, 9.00), and 5.94 (3.27, 10.00). After adjusting for seroprevalences, the R0 (IQR) estimates for EV-A71, CV-A16 (optimistic and conservative scenarios), and CV-A6 were 12.60 (7.35, 25.40), 9.29 (6.01, 19.20), 15.50 (9.77, 30.40), and 25.80 (14.20, 43.50), respectively. We did not observe changes in the R0 of EV-A71 after vaccine licensure (P = .67).

Conclusions

HFMD is highly transmissible when caused by the 3 most common serotypes. In mainland China, it primarily affects young children. Although a vaccine became available in 2016, we have not yet observed any related changes in the disease dynamics.
Case report: Transcatheter valve repair with Cardioband: a new treatment option for secondary tricuspid regurgitation in cardiac transplant patients
Authors: Wösten Monique , Baldus Stephan , Pfister Roman
Published: December 2020

Background

Tricuspid regurgitation (TR) is the most frequent valvular complication after cardiac transplantation. As in native hearts, the role of surgical therapy particularly in secondary TR is unclear due to high procedural risk and unsatisfying results. Currently, percutaneous techniques are under development for TR repair with less procedural risk and promising preliminary results.

Case summary

We present a 67-year-old man who underwent heart transplantation (biatrial anastomosis) because of ischaemic heart disease 15 years ago and aortic valve replacement in 2010. Because of progressive severe dyspnoea (New York Heart Association Class III) in 2018 and signs of right heart failure with ascites he underwent transthoracic echocardiography which showed normal graft function, but massive TR of functional aetiology. The heart team decision was an interventional approach using the Cardioband System (Edwards Lifesciences) to treat TR based on the high risk associated with a third cardiac surgery and impaired right ventricular function. The procedure was performed in general anaesthesia with transoesophageal echocardiography and fluoroscopic guidance. Tricuspid regurgitation improved from massive to mild with a mean pressure gradient of 2.9 mmHg.

Discussion

This is the first case report of Cardioband implantation in tricuspid position in a heart transplant patient with the good technical and clinical result, suggesting that this technique might offer a treatment option to highly selected post-transplant patients with secondary severe TR and high surgical risk.
A case report of acute myopericarditis associated with Graves’ thyrotoxicosis
Authors: Anderton Thomas S , Saunderson Christopher E D , Jain Manali , Sengupta Anshuman
Published: December 2020

Background 

The effects of hyperthyroidism on the heart are well documented, primarily consisting of supraventricular tachycardias, congestive heart failure, and dilated cardiomyopathy. Acute myopericarditis resulting from a hyperthyroid state is an uncommon but recognized association.

Case summary 

A 29-year-old man with a history of Graves’ disease presented with chest pain and electrocardiogram changes suggestive of an infero-lateral ST-elevation myocardial infarction. However, emergent coronary angiography and bedside echocardiography were normal. Troponin-I was found to be >25 000 ng/L (normal value <57). Thyroid function tests showed a significantly raised free T4 and undetectable thyroid-stimulating hormone. Cardiovascular magnetic resonance (CMR) showed extensive myocardial oedema and late gadolinium enhancement (LGE) in keeping with acute myopericarditis, alongside an enlarged thyroid gland consistent with goitre. Propylthiouracil in combination with an angiotensin-converting enzyme inhibitor and beta-blocker were commenced and eventually definitive treatment with thyroidectomy was performed. Follow-up CMR at 6 months showed complete resolution of the prior noted oedema and a reduction in the location and extent of LGE with significant residual fibrosis.

Discussion 

Acute myopericarditis is a common diagnosis in young patients presenting with symptoms of chest pain with elevated troponin and is frequently related to a viral illness. Hyperthyroid states are also associated with acute myopericarditis and should be particularly considered in patients with a pre-existing thyroid condition or in those with symptoms suggestive of hyperthyroidism. Given the specific treatments required in a case of myopericarditis associated with hyperthyroidism, it is important to be aware of this association and consider screening where appropriate.
Corona Virus Disease 2019 in situ arterial and venous thrombosis in critically ill patients: a case series
Authors: Castro-Verdes Mireya , Gkouma Antonia , Wort John , Ridge Carole , Mirsadraee Saeed , Padley Simon , Sheikh Awais , Singh Suveer
Published: December 2020

Background

Corona Virus Disease 2019 (COVID-19) pneumonitis associated with severe respiratory failure carries a high mortality. Coagulopathy has emerged as a significant contributor to thrombotic complications.

Case summary

We describe two cases of severe COVID-19 pneumonitis refractory to conventional mechanical ventilation and proning position, transferred to our specialist centre for cardiorespiratory failure. Cross-sectional imaging demonstrated concurrent venous and aortic thrombosis with end-organ ischaemic changes. One patient received thrombolysis with a partial response. This could not be offered to the other patient due to a recent haemorrhagic event. Both patients died of multi-organ failure in the hospital.

Discussion

Concurrent aortic and venous thromboses are rare. This finding in COVID-19 cases, who were both critically ill patients, likely reflects the strongly thrombogenic nature of this illness which ultimately contributed to poor outcomes. The absence of deep vein thrombosis or a potential systemic source of embolism suggests in situ thrombosis. Further, the management of anticoagulation and thrombolysis is challenging in patients where an attendant bleeding risk exists.
Subcutaneous implantable cardioverter-defibrillator was inappropriate for use in a patient with aborted sudden cardiac death due to coronary spastic angina: a case report
Authors: Kojima Akiteru , Shirayama Takeshi , Shiraishi Jun , Sawada Takahisa
Published: December 2020

Background

Implantable cardioverter-defibrillator (ICD) is recommended for secondary prevention in patients with coronary spastic angina and aborted sudden cardiac death. The effectiveness of subcutaneous ICD (S-ICD) for patients with coronary artery spastic angina is controversial.

Case summary

A 54-year-old man presented with ventricular fibrillation. Emergent coronary angiography showed diffuse narrowing of the coronary arteries that was reversible with isosorbide dinitrate. He was diagnosed with coronary spastic angina. S-ICD was implanted after the administration of a calcium-channel blocker and nicorandil. Seven months after the implantation, he collapsed again due to sinus node dysfunction and atrioventricular block caused by cardiac ischaemia. He developed cardiac arrest at both admissions. Six hours after the admission, electrocardiogram showed transient right bundle branch block. Inappropriate shocks were delivered because of low R-wave amplitude and T-wave oversense. S-ICD was replaced with a transvenous device in order to manage these two arrhythmias and inappropriate shocks.

Discussion

Patients with coronary artery spasm and aborted sudden cardiac death are candidates for implantation of S-ICD, but there are risks of bradycardia and inappropriate shocks in other ischaemic events.
Acute myocardial infarction associated with prosthetic valve leaflet thrombosis after transcatheter aortic valve implantation: a case report
Authors: Rotta Detto Loria Johannes , Thiele Holger , Abdel-Wahab Mohamed
Published: December 2020

Background

Fatal thrombo-embolic events like cerebral stroke or myocardial infarction are rare complications of prosthetic heart valve leaflet thrombosis. Nevertheless, prevention and management of leaflet thrombosis is gaining increased attention, particularly with the widespread adoption of transcatheter heart valves.

Case summary

We herein present the case of a 79-year-old man who had undergone a transcatheter aortic valve implantation procedure. Seven months later, he presented with a non-ST-segment elevation myocardial infarction. Coronary angiography did not reveal obstructive lesions. A dedicated cardiac computed tomography scan showed thrombosis of both right- and non-coronary leaflets of the prosthetic aortic valve, while prosthetic valve function was normal on echocardiography. Transmural myocardial infarction lesions in the midventricular and apical inferior wall were detected by cardiac magnetic resonance imaging.

Discussion

Subclinical leaflet thrombosis of prosthetic aortic valves is a common finding. In this case report, we show that myocardial infarction presumably due to leaflet thrombosis was the first symptom in an otherwise asymptomatic patient. This finding raises the question of the validity in distinguishing between subclinical and clinical leaflet thrombosis based on prosthetic valve function.
Intra-cardiac microcomputer allows for innovative telemedicine in chronic heart failure during coronavirus disease-2019 pandemic: a case report
Authors: Feickert Sebastian , D’Ancona Giuseppe , Murero Monica , Ince Hüseyin
Published: December 2020

Background 

Heart failure patient management guided by invasive intra-cardiac and pulmonary pressure measurements through permanent intra-cardiac micro-sensors has recently been published as a strategy to individualize the therapy of patients with chronic heart failure to reduce re-hospitalization and optimize quality of life. Furthermore, the use of telemedicine could have an important impact on infective disease spread during the current coronavirus disease-2019 pandemic.

Case summary 

Emergent hospitalization of a patient with acute on chronic heart failure, who is currently in self-isolation as a result of his comorbid profile that exposes him to high risk for severe course and mortality in case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was prevented using a last generation telemedicine tool.

Discussion 

Further implementation of invasive telemedicine could prevent hospitalization for acute decompensated heart failure and consecutive exposure to a potential hospital infection with SARS-CoV-2 in high-risk patients.
Be aware of misdiagnosis tied to COVID-19 focusing: a case report of abciximab-induced alveolar haemorrhage thought to be SARS-CoV-2 in a patient with ST-segment elevation myocardial infarction
Authors: Turan Turhan , Sayın Muhammet Raşit , Kul Selim , Akyüz Ali Rıza
Published: December 2020

Background

Early diagnosis of diffuse alveolar haemorrhage (DAH) can be extremely difficult, as the common clinical picture is often attributed to more common clinical conditions. High degree of suspicion is key to diagnosis which can be much more difficult during the coronavirus disease 2019 (COVID-19) pandemic.

Case summary

A 61-year-old man with inferolateral ST-segment elevation myocardial infarction treated by a stent to the left circumflex artery and intravenous abciximab treatment was started for the high thrombus burden. Two hours later, the patient developed dyspnoea and hypoxaemia. Chest examination revealed diffuse rales over both lung fields. Chest X-ray revealed bilateral diffuse alveolar infiltrates, while the echocardiography was normal. Chest computed tomography (CT) was performed and the ‘crazy paving appearance’, which is the typical radiological finding of COVID-19, was reported. The patient was considered to be suspected of COVID-19 and was transferred to a quarantine unit. Real-time reverse transcriptase–polymerase chain reaction (RT-PCR) test was obtained and azithromycin and hydroxychloroquine were initiated. 48 h later, 2.6 mmol/L reduction was observed in haemoglobin levels and haemoptysis was developed. After the second negative RT-PCR with an interval of 24 h, CT was repeated and the patient was diagnosed to have abciximab-induced DAH. The patient was later followed up conventionally and discharged after two weeks without additional complications.

Discussion

DAH and COVID-19 might share common clinical and radiological findings during examination. The physicians must be aware of the high motivation of the COVID-19 pandemic which can lead to misdiagnosis by overlooking other important clinical conditions.
Expected Covering Radius of a Translation Surface
Authors: Masur Howard , Rafi Kasra , Randecker Anja
Published: December 2020

A translation structure equips a Riemann surface with a singular flat metric. Not much is known about the shape of a random translation surface. We compute an upper bound on the expected value of the covering radius of a translation surface in any stratum ${{\mathcal{H}}}_1(\kappa )$. The covering radius of a translation surface is the largest radius of an immersed disk. In the case of the stratum ${{\mathcal{H}}}_1(2g-2)$ of translation surfaces of genus $g$ with one singularity, the covering radius is comparable to the diameter. We show that the expected covering radius of a surface is bounded above by a uniform multiple of $\sqrt{ \frac{\log g}{g}}$, independent of the stratum. This is smaller than what one would expect by analogy from the result of Mirzakhani about the expected diameter of a hyperbolic metric on a Riemann surface. To prove our result, we need an estimate for the volume of the thin part of ${{\mathcal{H}}}_1(\kappa )$, which is given in the appendix.
Reanimating Historical Violence in Multi-Ethnic Graphic Narratives
Authors: Kim Joo Ok
Published: December 2020

The ongoing damage of hurricanes impacting the Gulf regions of the United States, and beyond, resurrect the legacies of Hurricane Katrina. Hurricane Katrina exposed the degree to which militarized humanitarianisms linked the “natural” disaster of the hurricane and US military violence in Iraq. In cultural production, scholarship, and social critique, Hurricane Katrina and the Iraq War are historically linked discourses. Understanding both events through the fragmented representations of graphic narratives, in particular, compels reconsiderations of the hurricane and the war. In my examination of two graphic narratives, Mario Acevedo and Alberto Dose's Killing the Cobra: Chinatown Trollop (2010) and Mat Johnson and Simon Gane's Dark Rain: A New Orleans Story (2010), I analyze how the recurring presence of Iraqi civilian murder by the US military entwines the Iraq War and Hurricane Katrina. The graphic narratives lay bare the liberal maintenance of transnational violence that undo simple distinctions between “at home” and “abroad.” Indeed, both graphic narratives attend to fractures as form and content to structure the geohistorical dynamics of militarized duty in Iraq with foundational legacies of racism in the United States. How the graphic narratives frame the war—spatially fragmented, aggressively nonlinear—reanimates the intertwined cultural histories of Hurricane Katrina and the Iraq War. In their representations of mourning civilian deaths, and the convergence of humanitarian and military force in post-Hurricane Katrina New Orleans, Killing the Cobra and Dark Rain graft the war-sanctioned violence against Iraqi civilians onto militarized registers of US domestic space, tracing the fractures of transnational humanitarian empire.