bluuebunny/crossref_metadata_2025 huggingface dataset:
Front delineation and tracking with multiple underwater vehicles
Authors: Branch Andrew , Flexas Mar M. , Claus Brian , Thompson Andrew F. , Zhang Yanwu , Clark Evan B. , Chien Steve , Fratantoni David M. , Kinsey James C. , Hobson Brett , Kieft Brian , Chavez Francisco P.
Published: December 2018

This study describes a method for detecting and tracking ocean fronts using multiple autonomous underwater vehicles (AUVs). Multiple vehicles, equally spaced along the expected frontal boundary, complete near parallel transects orthogonal to the front. Two different techniques are used to determine the location of the front crossing from each individual vehicle transect. The first technique uses lateral gradients to detect when a change in the observed water property occurs. The second technique uses a measure of the vertical temperature structure over a single dive to detect when the vehicle is in upwelling water. Adaptive control of the vehicles ensure they remain perpendicular to the estimated front boundary as it evolves over time. This method was demonstrated in several experiment periods totaling weeks, in and around Monterey Bay, CA, in May and June of 2017. We compare the two front detection methods, a lateral gradient front detector and an upwelling front detector using the Vertical Temperature Homogeneity Index. We introduce two metrics to evaluate the adaptive control techniques presented. We show the capability of this method for repeated sampling across a dynamic ocean front using a fleet of three types of platforms: short‐range Iver AUVs, Tethys‐class long‐range AUVs, and Seagliders. This method extends to tracking gradients of different properties using a variety of vehicles.
Geometry of large Boltzmann outerplanar maps
Authors: Stefánsson Sigurdur Örn , Stufler Benedikt
Published: December 2018

We study the phase diagram of random outerplanar maps sampled according to nonnegative Boltzmann weights that are assigned to each face of a map. We prove that for certain choices of weights the map looks like a rescaled version of its boundary when its number of vertices tends to infinity. The Boltzmann outerplanar maps are then shown to converge in the Gromov‐Hausdorff sense towards the α‐stable looptree introduced by Curien and Kortchemski (2014), with the parameter α depending on the specific weight‐sequence. This allows us to describe the transition of the asymptotic geometric shape from a deterministic circle to the Brownian tree.
Recent Advances in 3D Graphene Architectures and Their Composites for Energy Storage Applications
Authors: Wang Zhijie , Gao Hong , Zhang Qing , Liu Yuqing , Chen Jun , Guo Zaiping
Published: December 2018

Graphene is widely applied as an electrode material in energy storage fields. However, the strong π–π interaction between graphene layers and the stacking issues lead to a great loss of electrochemically active surface area, damaging the performance of graphene electrodes. Developing 3D graphene architectures that are constructed of graphene sheet subunits is an effective strategy to solve this problem. The graphene architectures can be directly utilized as binder‐free electrodes for energy storage devices. Furthermore, they can be used as a matrix to support active materials and further improve their electrochemical performance. Here, recent advances in synthesizing 3D graphene architectures and their composites as well as their application in different energy storage devices, including various battery systems and supercapacitors are reviewed. In addition, their challenges for application at the current stage are discussed and future development prospects are indicated.
A Freestanding Stretchable and Multifunctional Transistor with Intrinsic Self‐Healing Properties of all Device Components
Authors: Khatib Muhammad , Huynh Tan‐Phat , Deng Yunfeng , Horev Yehu David , Saliba Walaa , Wu Weiwei , Haick Hossam
Published: December 2018

A flexible and stretchable field‐effect transistor (FET) is an essential element in a number of modern electronics. To realize the potential of this device in harsh real‐world conditions and to extend its application spectrum, new functionalities are needed to be introduced into the device. Here, solution‐processable elements based on carbon nanotubes that empower flexible and stretchable FET with high hole‐mobility (µh ≈ 10 cm2 V−1 s−1) and relatively low operating voltages (<8 V) and that retain self‐healing properties of all FET components are reported. The device has repeatable intrinsic and autonomic self‐healing ability, namely without use of any external trigger, enabling the restoration of its electrical and mechanical properties, both after microscale damage or complete cut of the device—for example by a scissor. The device can be repeatedly stretched for >200 cycles of up to 50% strain without a significant loss in its electrical properties. The device is applicable in the form of a ≈3 µm thick freestanding skin tattoo and has multifunctional sensing properties, such as detection of temperature and humidity. With this unprecedented biomimetic transistor, highly sustainable and reliable soft electronic applications can be introduced.
Self‐Powered Chemical Sensing Driven by Graphene‐Based Photovoltaic Heterojunctions with Chemically Tunable Built‐In Potentials
Authors: Lee Donghun , Park Haeli , Han Soo Deok , Kim Su Han , Huh Woong , Lee Jae Yoon , Kim Yoon Seok , Park Myung Jin , Park Won Il , Kang Chong‐Yun , Lee Chul‐Ho
Published: December 2018

Ultralow power chemical sensing is essential toward realizing the Internet of Things. However, electrically driven sensors must consume power to generate an electrical readout. Here, a different class of self‐powered chemical sensing platform based on unconventional photovoltaic heterojunctions consisting of a top graphene (Gr) layer in contact with underlying photoactive semiconductors including bulk silicon and layered transition metal dichalcogenides is proposed. Owing to the chemically tunable electrochemical potential of Gr, the built‐in potential at the junction is effectively modulated by absorbed gas molecules in a predictable manner depending on their redox characteristics. Such ability distinctive from bulk photovoltaic counterparts enables photovoltaic‐driven chemical sensing without electric power consumption. Furthermore, it is demonstrated that the hydrogen (H2) sensing properties are independent of the light intensity, but sensitive to the gas concentration down to the 1 ppm level at room temperature. These results present an innovative strategy to realize extremely energy‐efficient sensors, providing an important advancement for future ubiquitous sensing.
Electrochemical Reduction of CO2 over Heterogeneous Catalysts in Aqueous Solution: Recent Progress and Perspectives
Authors: Long Chang , Li Xiang , Guo Jun , Shi Yanan , Liu Shaoqin , Tang Zhiyong
Published: December 2018

Electrochemical reduction of CO2 into value‐added chemicals or fuels, driven by renewable energy, presents a promising solution to depletion of fossil fuels and greenhouse effects caused by excessive carbon emissions. In the past few years, great efforts have been dedicated to promote research in this field. Herein, this review focuses on the recent advances of the underlying mechanistic studies and novel heterogeneous catalyst constructions for electrochemical reduction of CO2 in aqueous media, targeting at presenting a full landscape at the current stage. The outlook for the future development is also included at the end of this review.
Deconstructing Retinal Organoids: Single Cell RNA-Seq Reveals the Cellular Components of Human Pluripotent Stem Cell-Derived Retina
Authors: Collin Joseph , Queen Rachel , Zerti Darin , Dorgau Birthe , Hussain Rafiqul , Coxhead Jonathan , Cockell Simon , Lako Majlinda
Published: December 2018

The rapid improvements in single cell sequencing technologies and analyses afford greater scope for dissecting organoid cultures composed of multiple cell types and create an opportunity to interrogate these models to understand tissue biology, cellular behavior and interactions. To this end, retinal organoids generated from human embryonic stem cells (hESCs) were analyzed by single cell RNA-sequencing (scRNA-Seq) at three time points of differentiation. Combinatorial data from all time points revealed the presence of nine clusters, five of which corresponded to key retinal cell types: retinal pigment epithelium (RPE), retinal ganglion cells (RGCs), cone and rod photoreceptors, and Müller glia. The remaining four clusters expressed genes typical of mitotic cells, extracellular matrix components and those involved in homeostasis. The cell clustering analysis revealed the decreasing presence of mitotic cells and RGCs, formation of a distinct RPE cluster, the emergence of cone and rod photoreceptors from photoreceptor precursors, and an increasing number of Müller glia cells over time. Pseudo-time analysis resembled the order of cell birth during retinal development, with the mitotic cluster commencing the trajectory and the large majority of Müller glia completing the time line. Together, these data demonstrate the feasibility and potential of scRNA-Seq to dissect the inherent complexity of retinal organoids and the orderly birth of key retinal cell types. Stem Cells  2019;37:593–598
Existence of weak solutions for a Bingham fluid-rigid body system
Authors: Obando Benjamin , Takahashi Takéo
Published: December 2018

We consider the motion of a rigid body in a viscoplastic material. This material is modeled by the 3D Bingham equations, and the Newton laws govern the displacement of the rigid body. Our main result is the existence of a weak solution for the corresponding system. The weak formulation is an inequality (due to the plasticity of the fluid), and it involves a free boundary (due to the motion of the rigid body). We approximate it by regularizing the convex terms in the Bingham fluid and by using a penalty method to take into account the presence of the rigid body.
Input size independent efficient quality meshing of the interior of 2D point cloud data
Authors: Singh Neha , Ray Tathagata , Parimi Chandu , Kuchibhotla Srivastava
Published: December 2018

This paper describes a framework to generate an unstructured Delaunay mesh of a two-dimensional domain whose boundary is specified by a point cloud data (PCD). The assumption is that the PCD is sampled from a smooth 1-manifold without a boundary definition and is significantly dense (at least ∊-sampled where ∊<1). Presently meshing of such a domain requires two explicit steps, namely the extraction of model definition from the PCD and the use of model definition to guide the unstructured mesh generation. For a densely sampled PCD, the curve reconstruction process is dependent on the size of input PCD and can become a time-consuming overhead. We propose an optimized technique that bypasses the explicit step of curve reconstruction by implicit access to the model information from a well-sampled PCD. A mesh thus generated will be optimal, as the fineness of the mesh is not dictated by the sampling of PCD, but only the geometric complexity of the underlying curve. The implementation and experiments of the proposed framework show significant improvement in expense over the traditional methodology. The main contribution of this paper is the circumvention of the explicit time-consuming step of boundary computation which is a function of the PCD sampling size and a direct generation of a mesh whose complexity is dictated by the geometry of the domain.

Highlights The algorithm gives a size optimal triangular mesh directly from a point cloud data. Intermediate step of model definition can be skipped completely. Generated mesh is independent of the number of points in the data. Mesh size and computational time depend on geometric complexity of the curve. For dense samples, this method is very efficient compared to traditional methods.
Penile Prosthesis Reservoir Removal: Surgical Description and Patient Outcomes
Authors: Clavell-Hernández J. , Aly S. G. , Wang R. , Sadeghi-Nejad H.
Published: December 2018

Background

Removal of the penile prosthesis reservoir can be technically challenging because of its difficult locations either deep in the pelvis or high in the abdominal wall.

Aim

To describe a detailed surgical technique for reservoir removal through a penoscrotal approach.

Methods

We describe our preferred method for removal of prosthetic reservoir and present a retrospective review of patient outcomes after reservoir removal.

Main Outcome Measure

Primary outcomes included immediate or late complications. Secondary outcomes included operative time.

Results

34 patients underwent reservoir removal with the use of our described technique. 23 patients (67.6%) had reservoirs removed because of device malfunction and 11 (32.4%) because of infection. A total of 18 reservoirs (52.9%) were found in the space of Retzius (SOR), whereas the other 16 (47.1%) were in an alternative/ectopic space. 2 cases (5.9%) required a counterincision to remove the reservoir. Mean overall operative time was 96.2 minutes (range 35–175). There were no complications in this series. There was no statistical difference in operative time between reservoirs removed because of malfunction when compared with infection (P = .283). However, there was a difference in operative time between reservoirs removed from the SOR when compared with those removed from an ectopic space, with mean operating room times of 104.5 and 75.4 minutes, respectively (P = .001).

Clinical Implications

Reservoir removal through a penoscrotal incision is feasible and safe.

Strength & Limitations

This is the first report, to our knowledge, describing surgical techniques and outcomes for reservoir removal. Limitations include its retrospective nature and lack of validated questionnaires to assess patient satisfaction.

Conclusion

Although removal of a reservoir deep in the SOR or placed in alternate/ectopic locations can be challenging, the use of a lighted retractor, meticulous dissection, and a few technical maneuvers described allow for safe removal of the reservoir completely intact while avoiding complications. Our technique for a secondary incision in particularly difficult cases is also described.
Early Cretaceous trachybasalt–trachyte–trachyrhyolitic volcanism in the Nyalga basin (Central Mongolia): sources and evolution of continental rift magmas
Authors: Peretyazhko I.S. , Savina E.A. , Dril’ S.I.
Published: December 2018

As shown by geological, mineralogical, and isotope geochemical data, trachybasaltic–trachytic–trachyrhyolitic (TTT) rocks from the Nyalga basin in Central Mongolia result from several eruptions of fractionated magmas within a short time span at about 120 Ma. Their parental basaltic melts formed by partial melting of mantle peridotite which was metasomatized and hydrated during previous subduction events. Basaltic trachyandesites have high TiO2 and K2O, relatively high P2O5, and low MgO contents, medium 87Sr/86Sr(0) ratios (0.70526–0.70567), and almost zero or slightly negative εNd(T) values. The isotope geochemical signatures of TTT rocks are typical of Late Mesozoic basaltic rocks from rift zones of Mongolia and Transbaikalia. The sources of basaltic magma at volcanic centers of Northern and Central Asia apparently moved from a shallower and more hydrous region to deeper and less hydrated lithospheric mantle (from spinel to garnet-bearing peridotite) between the Late Paleozoic and the latest Mesozoic. The geochemistry and mineralogy of TTT rocks fit the best models implying fractional crystallization of basaltic trachyandesitic, trachytic, and trachyrhyodacitic magmas. Mass balance calculations indicate that trachytic and trachydacitic magmas formed after crystallization of labradorite-andesine, Ti-augite, Sr-apatite, Ti-magnetite, and ilmenite from basaltic trachyandesitic melts. The melts evolved from trachytic to trachyrhyodacitic and trachyrhyolitic compositions as a result of prevalent crystallization of K–Na feldspar, with zircon, chevkinite-Ce, and LREE-enriched apatite involved in fractionation. Trachytic, trachyrhyodacitic, and trachyrhyolitic residual melts were produced by the evolution of compositionally different parental melts (basaltic trachyandesitic, trachytic, and trachyrhyodacitic, respectively), which moved to shallower continental crust and accumulated in isolated chambers. Judging by their isotopic signatures, the melts assimilated some crustal material, according to the assimilation and fractional crystallization (AFC) model.
Participant outcomes and preferences in Alzheimer's disease clinical trials: The electronic Person‐Specific Outcome Measure (ePSOM) development program
Authors: Saunders Stina , Muniz‐Terrera Graciela , Watson Julie , Clarke Charlotte L. , Luz Saturnino , Evans Alison R. , Ritchie Craig W.
Published: December 2018

Introduction

Current pharmacological interventions for Alzheimer's dementia delay symptom progression for about a year. Although the outcomes in earlier disease states may include changes in biomarkers, the clinical effectiveness of any intervention can ultimately only be assessed by a patient's self‐reported well‐being. A better understanding of earlier manifestations of Alzheimer's disease and the drive for relevant outcome measures, allied to technological advances in artificial intelligence, have mediated the electronic Person‐Specific Outcome Measure (ePSOM) development program.

Methods

There are 4 sequential stages in the ePSOM development program—(1) literature review, (2) focus group study, (3) national survey, and (4) development of an app for capturing person‐specific outcomes. Here, we report the overall approach to the program incorporating our literature review on patient‐reported outcome measures and patient preferences in the Alzheimer's disease population.

Results

Alzheimer's disease trials do not use any patient‐reported outcome measures. Quality of life measures are often used as proxies for this, but they do not capture individual needs. Therefore, trials currently fail to reflect the participant's aspirations for effect but rather default to clinicostatistical measure of cognition and function. There is no implementation of patient preferences despite evidence that understanding preferences may influence adherence to treatment.

Discussion

It is important to consider preferences for an intervention and use PROMs for the measure of effectiveness given that both risk and benefit are judged by the recipient of the treatment. The ePSOM development program will deliver the methodology for incorporating meaningful outcomes in clinical trials to expand upon current biological and clinical measurements of effectiveness.
Molecular analysis of bacterial contamination on stethoscopes in an intensive care unit
Authors: Knecht Vincent R. , McGinniss John E. , Shankar Hari M. , Clarke Erik L. , Kelly Brendan J. , Imai Ize , Fitzgerald Ayannah S. , Bittinger Kyle , Bushman Frederic D. , Collman Ronald G.
Published: December 2018

Background

Culture-based studies, which focus on individual organisms, have implicated stethoscopes as potential vectors of nosocomial bacterial transmission. However, the full bacterial communities that contaminate in-use stethoscopes have not been investigated.

Methods

We used bacterial 16S rRNA gene deep-sequencing, analysis, and quantification to profile entire bacterial populations on stethoscopes in use in an intensive care unit (ICU), including practitioner stethoscopes, individual-use patient-room stethoscopes, and clean unused individual-use stethoscopes. Two additional sets of practitioner stethoscopes were sampled before and after cleaning using standardized or practitioner-preferred methods.

Results

Bacterial contamination levels were highest on practitioner stethoscopes, followed by patient-room stethoscopes, whereas clean stethoscopes were indistinguishable from background controls. Bacterial communities on stethoscopes were complex, and community analysis by weighted UniFrac showed that physician and patient-room stethoscopes were indistinguishable and significantly different from clean stethoscopes and background controls. Genera relevant to healthcare-associated infections (HAIs) were common on practitioner stethoscopes, among which Staphylococcus was ubiquitous and had the highest relative abundance (6.8%–14% of contaminating bacterial sequences). Other HAI-related genera were also widespread although lower in abundance. Cleaning of practitioner stethoscopes resulted in a significant reduction in bacterial contamination levels, but these levels reached those of clean stethoscopes in only a few cases with either standardized or practitioner-preferred methods, and bacterial community composition did not significantly change.

Conclusions

Stethoscopes used in an ICU carry bacterial DNA reflecting complex microbial communities that include nosocomially important taxa. Commonly used cleaning practices reduce contamination but are only partially successful at modifying or eliminating these communities.
Extending Global Continuous Geomagnetic Field Reconstructions on Timescales Beyond Human Civilization
Authors: Panovska S. , Constable C. G. , Korte M.
Published: December 2018

Study of the late Quaternary geomagnetic field contributes significantly to understanding the origin of millennial‐scale paleomagnetic secular variations, the structure of geomagnetic excursions, and the long‐term shielding by the geomagnetic field. A compilation of paleomagnetic sediment records and archeomagnetic and lava flow data covering the past 100 ka enables reconstruction of the global geomagnetic field on such long‐term scales. We use regularized inversion to build the first global, time‐dependent, geomagnetic field model spanning the past 100 ka, named GGF100k (Global Geomagnetic Field over the past 100 ka). Spatial parametrization of the model is in spherical harmonics and time variations with cubic splines. The model is heavily constrained by more than 100 continuous sediment records covering extended periods of time, which strongly prevail over the limited number of discrete snapshots provided by archeomagnetic and volcanic data. Following an assessment of temporal resolution in each sediment's magnetic record, we have introduced smoothing kernels into the forward modeling when assessing data misfit. This accommodates the smoothing inherent in the remanence acquisition in individual sediment paleomagnetic records, facilitating a closer fit to both high‐ and low‐resolution records in regions where some sediments have variable temporal resolutions. The model has similar spatial resolution but less temporal complexity than current Holocene geomagnetic field models. Using the new reconstruction, we discuss dipole moment variations, the time‐averaged field, and paleomagnetic secular variation activity. The new GGF100k model fills the gap in the geomagnetic power spectrum in the frequency range 100–1,000 Ma−1.
Snowpack Change From 1982 to 2016 Over Conterminous United States
Authors: Zeng Xubin , Broxton Patrick , Dawson Nicholas
Published: December 2018

Snow water equivalent (SWE) variability and its drivers over different regions remain uncertain due to lack of representativeness of point measurements and deficiencies of existing coarse‐resolution SWE products. Here, for the first time, we quantify and understand the snowpack change from 1982 to 2016 over conterminous United States at 4‐km pixels. Annual maximum SWE decreased significantly (p < 0.05) by 41% on average for 13% of snowy pixels over western United States. Snow season was shortened significantly by 34 days on average for 9% of snowy pixels over the United States, primarily caused by earlier ending and later arrival of the season over western and eastern United States, respectively. October–March mean temperature and accumulated precipitation largely explain the temporal variability of 1 April SWE over western United States, and considering temperature alone would exaggerate the warming effect on SWE decrease. In contrast, temperature plays the primary role in the 1 April SWE variability over eastern United States.
The Effects of Hydrate on the Strength and Stiffness of Some Sands
Authors: Madhusudhan B. N. , Clayton C. R. I. , Priest J. A.
Published: December 2018

Gas hydrates can form more or less at the same time as seafloor sediment. They can have the effect of significantly stiffening and strengthening deep‐ocean sediments. Subsequent increases in situ temperature or decreases in pressure may trigger hydrate dissociation, leading to large reductions in the strength and stiffness of the sediment and possible seafloor instability. Gas hydrate dissociation not only removes cementing. It also releases freshwater and significant amounts of trapped gas that are dependent on multiple factors such as type of sediment, available pore space, hydrate morphology, and hydrate saturation. The presence of pock marks in areas of known seabed instability suggests that hydrate dissociation may have been a factor in triggering failure at these locations. Having reviewed the mechanisms by which the strength and stiffness of seabed sediment may be changed during dissociation, this paper reports the results of laboratory testing to evaluate the effects of loss of hydrate cement on strength and stiffness, for a range of sand‐sized materials with differing particle size, specific surface area, and particle shape, using a laboratory gas hydrate triaxial apparatus. The results suggest that both the strength and the stiffness of hydrate‐cemented granular materials are affected significantly by the specific surface available for hydrate cementation and, to a certain extent, by the particle shape. Uniform coarse granular sediments of lower specific surface area can suffer significant loss of stiffness and strength upon hydrate dissociation, changing the sediment from dilative to contractive. Finer‐grained sediments appear less affected by dissociation.
Deviation of Wind Stress From Wind Direction Under Low Wind Conditions
Authors: Chen Sheng , Qiao Fangli , Huang Chuan Jiang , Zhao Biao
Published: December 2018

The deviation of the wind stress vector from the wind direction at the air‐sea interface under low wind conditions was investigated based on direct eddy covariance flux measurements taken at a coastal tower in the northern South China Sea. The wind stress deviates significantly from the mean wind direction under low wind conditions, with the deviation angle sometimes exceeding 90°, indicating upward momentum transfer from the ocean to the atmosphere. Negative downwind drag coefficient values begin to occur at a wind speed of approximately 4 m/s. Our results show that ocean swells and nonstationary airflow play critical roles in wind stress. Prominent peaks at the dominant swell frequency in the vertical velocity spectra are observed at a height of 17 m over the mean sea surface, implying that swell‐induced perturbations can reach a height of at least 17 m, and the wave boundary layer can extend more than 10 m above the sea surface. The results of our analysis indicate that at the observation height, the influence of nonstationarity in the wind field is more significant than that of swell‐induced motions on the deviation of wind stress. After the removal of nonstationary motions, the deviation angles of the wind stress from the wind direction are generally reduced and vary substantially at low wind speeds.
Intertidal Area Disappears Under Sea Level Rise: 250 Years of Morphodynamic Modeling in San Pablo Bay, California
Authors: Elmilady H. , van der Wegen M. , Roelvink D. , Jaffe B. E.
Published: December 2018

Anticipated sea level rise (SLR) threatens intertidal areas and associated ecosystems in estuaries worldwide. There is a need to develop validated modeling tools to assess the impact of SLR on estuarine morphodynamics. This study explores the morphological impact of SLR on a channel‐shoal system in San Pablo Bay, a subembayment of San Francisco Bay, California, using a 3‐D, process‐based modeling approach (Delft3D) including density currents and wave action. The Bay underwent considerable morphologic development in response to variations in fluvial sediment load and discharge associated with a period of hydraulic mining for gold and later damming in the watershed. The availability of a unique 150‐year, 30‐year sequenced, bathymetric data set provided a rare opportunity for model validation. We investigate a 250‐year period of morphodynamic evolution including a 150‐year hindcast and a 100‐year forecast with different SLR scenarios. The model shows significant skill in hindcasting volumes and patterns of bathymetric development during both net depositional (1856–1951) and erosional (1951–onward) periods. Forecasts show that SLR alters the Bay's erosional trend to a depositional trend again. Despite increased sediment trapping rates, the intertidal mudflats drown under all modeled SLR scenarios (42, 84, and 167 cm by end of the 21st century). Our work highlights the potential of using process‐based models to assess the morphodynamic impact of SLR. The study also suggests that SLR can greatly increase the loss of intertidal area when landward migration is not possible. Sustainable management strategies are required to safeguard these valuable intertidal habitats.
A Multi‐Timescale EnOI‐Like High‐Efficiency Approximate Filter for Coupled Model Data Assimilation
Authors: Yu X. , Zhang S. , Li J. , Lu L. , Liu Z. , Li M. , Yu H. , Han G. , Lin X. , Wu L. , Chang P.
Published: December 2018

Because it uses a set of model integrations to simulate the temporally varying background probability distribution function and implement Bayes' theorem, the ensemble Kalman filter (EnKF), which produces an optimal data assimilation solution that coherently combines model dynamics and observational information, has been widely used in weather and climate studies. However, in practice, the EnKF has two limitations: (1) the insufficient representation of error statistics of low‐frequency background flows due to its finite ensemble size and model integration over time and (2) the high demand of computational power for ensemble model integrations in high‐resolution coupled Earth system models. Given that background error statistics consist of stationary, slow‐varying, and fast‐varying parts, a multi‐timescale, high‐efficiency approximate EnKF (MSHea‐EnKF) is designed to increase the representation of low‐frequency background error statistics and enhance its computational efficiency. The MSHea‐EnKF is a combination of multi‐timescale filters implemented by regressions based on data sampled from the time series of a single‐model solution. Validation shows that with the improved representation of stationary and slow‐varying background statistics, the MSHea‐EnKF only requires a small fraction of computer resources and shows a comparable performance relative to a finite size EnKF. Our experiments also show that the result can be further improved by using a small set of MSHea‐EnKFs through second‐stage EnKF filtering if sufficient computer resources are available. This new algorithm makes it practical to assimilate multisource observations into any high‐resolution coupled Earth system model that is intractable with current computing power for weather‐climate analysis and predictions.
Calcium oscillations coordinate feather mesenchymal cell movement by SHH dependent modulation of gap junction networks
Authors: Li Ang , Cho Jung-Hwa , Reid Brian , Tseng Chun-Chih , He Lian , Tan Peng , Yeh Chao-Yuan , Wu Ping , Li Yuwei , Widelitz Randall B. , Zhou Yubin , Zhao Min , Chow Robert H. , Chuong Cheng-Ming
Published: December 2018

Collective cell migration mediates multiple tissue morphogenesis processes. Yet how multi-dimensional mesenchymal cell movements are coordinated remains mostly unknown. Here we report that coordinated mesenchymal cell migration during chicken feather elongation is accompanied by dynamic changes of bioelectric currents. Transcriptome profiling and functional assays implicate contributions from functional voltage-gated Ca2+ channels (VGCCs), Connexin-43 based gap junctions, and Ca2+ release activated Ca2+ (CRAC) channels. 4-Dimensional Ca2+ imaging reveals that the Sonic hedgehog-responsive mesenchymal cells display synchronized Ca2+ oscillations, which expand progressively in area during feather elongation. Inhibiting VGCCs, gap junctions, or Sonic hedgehog signaling alters the mesenchymal Ca2+ landscape, cell movement patterns and feather bud elongation. Ca2+ oscillations induced by cyclic activation of opto-cCRAC channels enhance feather bud elongation. Functional disruption experiments and promoter analysis implicate synergistic Hedgehog and WNT/β-Catenin signaling in activating Connexin-43 expression, establishing gap junction networks synchronizing the Ca2+ profile among cells, thereby coordinating cell movement patterns.
HDX-MS reveals dysregulated checkpoints that compromise discrimination against self RNA during RIG-I mediated autoimmunity
Authors: Zheng Jie , Wang Chen , Chang Mi Ra , Devarkar Swapnil C. , Schweibenz Brandon , Crynen Gogce C. , Garcia-Ordonez Ruben D. , Pascal Bruce D. , Novick Scott J. , Patel Smita S. , Marcotrigiano Joseph , Griffin Patrick R.
Published: December 2018

Retinoic acid inducible gene-I (RIG-I) ensures immune surveillance of viral RNAs bearing a 5’-triphosphate (5’ppp) moiety. Mutations in RIG-I (C268F and E373A) lead to impaired ATPase activity, thereby driving hyperactive signaling associated with autoimmune diseases. Here we report, using hydrogen/deuterium exchange, mechanistic models for dysregulated RIG-I proofreading that ultimately result in the improper recognition of cellular RNAs bearing 7-methylguanosine and N1-2’-O-methylation (Cap1) on the 5’ end. Cap1-RNA compromises its ability to stabilize RIG-I helicase and blunts caspase activation and recruitment domains (CARD) partial opening by threefold. RIG-I H830A mutation restores Cap1-helicase engagement as well as CARDs partial opening event to a level comparable to that of 5’ppp. However, E373A RIG-I locks the receptor in an ATP-bound state, resulting in enhanced Cap1-helicase engagement and a sequential CARDs stimulation. C268F mutation renders a more tethered ring architecture and results in constitutive CARDs signaling in an ATP-independent manner.
Practice and perspectives in the validation of resource management models
Authors: Eker Sibel , Rovenskaya Elena , Obersteiner Michael , Langan Simon
Published: December 2018

Quantitative modelling is commonly used to assist the policy dimension of sustainability problems. Validation is an important step to make models credible and useful. To investigate existing validation viewpoints and approaches, we analyse a broad academic literature and conduct a survey among practitioners. We find that empirical data plays an important role in the validation practice in all main areas of sustainability science. Qualitative and participatory approaches that can enhance usefulness and public reliability are much less visible. Data-oriented validation is prevalent even when models are used for scenario exploration. Usefulness regarding a given task is more important for model developers than for users. As the experience of modellers and users increases, they tend to better acknowledge the decision makers’ demand for clear communication of assumptions and uncertainties. These findings provide a reflection on current validation practices and are expected to facilitate communication at the modelling and decision-making interface.
Ultimate limit in size and performance of WSe2 vertical diodes
Authors: Nazir Ghazanfar , Kim Hakseong , Kim Jihwan , Kim Kyoung Soo , Shin Dong Hoon , Khan Muhammad Farooq , Lee Dong Su , Hwang Jun Yeon , Hwang Chanyong , Suh Junho , Eom Jonghwa , Jung Suyong
Published: December 2018

Precise doping-profile engineering in van der Waals heterostructures is a key element to promote optimal device performance in various electrical and optical applications with two-dimensional layered materials. Here, we report tungsten diselenide- (WSe2) based pure vertical diodes with atomically defined p-, i- and n-channel regions. Externally modulated p- and n-doped layers are respectively formed on the bottom and the top facets of WSe2 single crystals by direct evaporations of high and low work-function metals platinum and gadolinium, thus forming atomically sharp p–i–n heterojunctions in the homogeneous WSe2 layers. As the number of layers increases, charge transport through the vertical WSe2 p–i–n heterojunctions is characterized by a series of quantum tunneling events; direct tunneling, Fowler–Nordheim tunneling, and Schottky emission tunneling. With optimally selected WSe2 thickness, our vertical heterojunctions show superb diode characteristics of an unprecedentedly high current density and low turn-on voltages while maintaining good current rectification.
Unconventional magneto-transport in ultrapure PdCoO2 and PtCoO2
Authors: Nandi Nabhanila , Scaffidi Thomas , Kushwaha Pallavi , Khim Seunghyun , Barber Mark E. , Sunko Veronika , Mazzola Federico , King Philip D. C. , Rosner Helge , Moll Philip J. W. , König Markus , Moore Joel E. , Hartnoll Sean , Mackenzie Andrew P.
Published: December 2018

The single-band, quasi-two dimensional metals PdCoO2 and PtCoO2 have recently come to prominence because of their extremely long mean free paths, which establish them as some of the most electronically pure materials known, and as potential hosts of previously unobservable regimes of electronic transport. To fully establish their magnetotransport properties, we have studied the magnetoresistance and Hall effect in bulk single crystals to which electrical contacts have been made with high precision using focused ion beam machining. We observe a strong temperature dependence of the Hall resistivity in small applied fields, linked to a large violation of Kohler’s rule in the magnetoresistance. We discuss the extent to which these observations can be accounted for by standard transport theory.
Deficiency of apoptosis-stimulating protein two of p53 promotes liver regeneration in mice by activating mammalian target of rapamycin
Authors: Shi Hongbo , Zhang Yizhi , Ji Jing , Xu Ping , Shi Honglin , Yue Xiujuan , Ren Feng , Chen Yu , Duan Zhongping , Chen Dexi
Published: December 2018

Although liver regeneration has been intensively studied in various ways, the mechanisms underlying liver regeneration remain elusive. Apoptosis-stimulating protein two of p53 (ASPP2) was discovered as a binding partner of p53 and plays an important role in regulating cell apoptosis and growth. However, the role of ASPP2 in hepatocyte proliferation and liver regeneration has not been reported. The expression profile of ASPP2 was measured in a mouse model with 70% partial hepatectomy (PHX). Liver regeneration and hepatocyte proliferation were detected in wild-type (ASPP2+/+) and ASPP2 haploinsufficient (ASPP2+/−) mice with PHX. The mammalian target of rapamycin (mTOR) and autophagy pathways were analyzed in the ASPP2+/+ and ASPP2+/− mice with PHX. After rapamycin or 3-methyladenine (3-MA) treatment, hepatocyte proliferation and liver regeneration were analyzed in the ASPP2+/+ and ASPP2+/− mice with PHX. ASPP2 expression was shown to be upregulated at the early stage and downregulated at the late stage. Compared to the ASPP2+/+ mice, liver regeneration was enhanced in ASPP2+/− mice with 70% PHX. In addition, compared to the ASPP2+/+ mice, the mTORC1 pathway was significantly upregulated and the autophagic pathway was downregulated in ASPP2+/−mice with 70% PHX. Inhibition of the mTORC1 pathway significantly suppressed liver regeneration in ASPP2+/− mice with 70% PHX. In contrast, disruption of the autophagic pathway further enhanced liver regeneration in ASPP2+/− mice with 70% PHX. ASPP2 deficiency can promote liver regeneration through activating the mTORC1 pathway, which further regulates downstream molecules, such as those related to autophagy and p70S6K expression in mouse model post-PHX.
Tropane alkaloids GC/MS analysis and low dose elicitors’ effects on hyoscyamine biosynthetic pathway in hairy roots of Algerian Datura species
Authors: Harfi Boualem , Khelifi Lakhdar , Khelifi-Slaoui Majda , Assaf-Ducrocq Corinne , Gontier Eric
Published: December 2018

Plant secondary metabolites play a major role in plant adaptation to stress. Species belonging to Solanaceae family and Datura genus produce tropane alkaloids: D. stramonium, D. tatula and D. innoxia. These species are cultivated for their hyoscyamine (HS) content, whence the interest of this study to induce transformed roots of these species with strain A4 of Agrobacterium rhizogenes. Hairy roots (HRs) of Datura were established at high frequency by infecting vitroplants. All HRs (343 independent lines) were next employed to study the production of HS and growth. A screening of HRs alkaloid content by GC/MS is performed; it reveals, for the first time, the production of 13 alkaloids by the selected root lines. The selection of high productive line offers an interesting option to enhance the productivity. As HS is the dominant compound, the lines of Datura species were selected for their characteristics for biomass and HS production. The elicitors salicylic acid (SA) and acetyl salicylic acid (ASA) were also used to increase HS production. The results showed that the optimal concentration of the two elicitors (AS and ASA) was 0.1 mM. The highest HS content (17.94 ± 0.14 mg g−1 D.W.) obtained in HRs of D. tatula treated with 0.1 mM of acetyl salicylic acid.
Auditory figure-ground analysis in rostral belt and parabelt of the macaque monkey
Authors: Schneider Felix , Dheerendra Pradeep , Balezeau Fabien , Ortiz-Rios Michael , Kikuchi Yukiko , Petkov Christopher I. , Thiele Alexander , Griffiths Timothy D.
Published: December 2018

Segregating the key features of the natural world within crowded visual or sound scenes is a critical aspect of everyday perception. The neurobiological bases for auditory figure-ground segregation are poorly understood. We demonstrate that macaques perceive an acoustic figure-ground stimulus with comparable performance to humans using a neural system that involves high-level auditory cortex, localised to the rostral belt and parabelt.
Click chemistry at the microscale
Authors: Hong Tingting , Liu Wenfang , Li Ming , Chen Chuanpin
Published: December 2018

This manuscript reviews recent developments in click chemistry in microscale systems.
Solid-phase synthesis of a novel phalloidin analog with on-bead and off-bead actin-binding activity
Authors: Blanc Antoine , Todorovic Mihajlo , Perrin David M.
Published: December 2018

Specific effectors of actin polymerization have found use as dynamic probes of cellular morphology that may be used to gauge cellular response to stimuli and drugs.
Engineering bioorthogonal protein–polymer hybrid hydrogel as a functional protein immobilization platform
Authors: Lim Samuel , Jung Gi Ahn , Muckom Riya J. , Glover Dominic J. , Clark Douglas S.
Published: December 2018

We demonstrate the one-step bioorthogonal synthesis of protein–polymer hybrid hydrogel as a functional protein immobilization platform.
An ultrastable metal–organic material emits efficient and broadband bluish white-light emission for luminescent thermometers
Authors: Yin Jinlin , Zhang Guiyang , Peng Chengdong , Fei Honghan
Published: December 2018

We discover a rare bluish white-light-emitting Sb3+-based coordination polymer with an unsually large Stokes shift of 230 nm (2.3 eV), ascribed to the assymetric–symmetric coordination shift of the Sb3+ centers.
A vanadium-based metal–organic phosphate framework material K2[(VO)2(HPO4)2(C2O4)] as a cathode for potassium-ion batteries
Authors: Liao Jiaying , Hu Qiao , Mu Jinxiao , He Xiaodong , Wang Shuo , Chen Chunhua
Published: December 2018

A layered metal–organic phosphate framework K2[(VO)2(HPO4)2(C2O4)] is investigated as a cathode for K-ion batteries.
Enhanced mechanical properties of a metal–organic framework by polymer insertion
Authors: Iizuka Tomoya , Honjo Kayako , Uemura Takashi
Published: December 2018

The mechanical properties of a metal–organic framework were highly improved by the insertion of polymer chains into the nanochannels.
Electrochemical nitrogen reduction to ammonia at ambient conditions on nitrogen and phosphorus co-doped porous carbon
Authors: Song Pengfei , Wang Hao , Kang Li , Ran Baocheng , Song Honghong , Wang Rongmin
Published: December 2018

N,P co-doped porous carbon as a highly efficient electrocatalyst for N2 fixation in aqueous solution under ambient conditions.
Double asymmetric hydrogenation of conjugated dienes: a self-breeding chirality route for C2 symmetric 1,4-diols
Authors: León Félix , Francos Javier , López-Serrano Joaquín , García-Garrido Sergio E. , Cadierno Victorio , Pizzano Antonio
Published: December 2018

Asymmetric hydrogenation of 1 is performed with good enantio- and diastereoselectivity with Rh-Duphos/BPE catalysts providing a self-breeding chirality process.
Zr4-Substituted polyoxometalate dimers decorated byd-tartaric acid/glycolic acid: syntheses, structures and optical/electrochemical properties
Authors: Ni Zhi-Hui , Li Hai-Lou , Li Xu-Yan , Yang Guo-Yu
Published: December 2018

Two Zr4-sandwiched Keggin polyoxometalates functionalized by chirald-tartaric acid and glycolic acid were hydrothermally synthesized and structurally characterized. Their optical and electrochemical properties have been investigated in detail.
Thermal and illumination effects on a PbI2 nanoplate and its transformation to CH3NH3PbI3 perovskite
Authors: Wang Jiming , Lin Dongxu , Zhang Tiankai , Long Mingzhu , Shi Tingting , Chen Ke , Liang Zhihong , Xu Jianbin , Xie Weiguang , Liu Pengyi
Published: December 2018

The vapor transformation of crystalline PbI2 nanoplates into CH3NH3PbI3 under annealing and illumination condition was systematically investigated in nanoscale, and the detail pathway of structural transformation and mechanism are discussed.
Emulsions stabilized with mixed SiO2 and Fe3O4 nanoparticles: mechanisms of stabilization and long-term stability
Authors: Koroleva M. , Bidanov D. , Yurtov E.
Published: December 2018

Using SiO2 and Fe3O4 nanoparticles as stabilizers makes it possible to obtain Pickering emulsions with long-term stability to coalescence and creaming.
Nonlinear diffusion, bonding, and mechanics of the interface between austenitic steel and iron
Authors: Qin Qin , He Wei , Xie Lu , Deng Junchao , Zhu Xuehui , Peng Qing
Published: December 2018

Diffusion and evolution of the atomic structure during the compression process.
Diaqua-β-octaferrocenyltetraphenylporphyrin: a multiredox-active and air-stable 16π non-aromatic species
Authors: Al-Shewiki Rasha K. , Korb Marcus , Hildebrandt Alexander , Zahn Stefan , Naumov Sergej , Buschbeck Roy , Rüffer Tobias , Lang Heinrich
Published: December 2018

Herein the synthesis and properties of the first β-octaferrocenyltetraphenylporphyrin, {TPPFc8(H2O)2}, in its extraordinary stable and non-aromatic 16π form are reported, showing seven separate reversible redox events.
Microwave-assisted synthesis: from a mononuclear {CoII} complex to {CoII9} solvomorphs
Authors: Collet Alexandra , Wilson Claire , Murrie Mark
Published: December 2018

Microwave-assisted control over nuclearity and solvomorphism.
Correction: Structural diversity in the alkaline earth metal compounds of tetra and pentacyanocyclopentadienide
Authors: Nimax Patrick R. , Sünkel Karlheinz
Published: December 2018

Correction for ‘Structural diversity in the alkaline earth metal compounds of tetra and pentacyanocyclopentadienide’ by Karlheinz Sünkel et al., Dalton Trans., 2018, 47, 409–417.
Synergistic modulation of mobility and thermal conductivity in (Bi,Sb)2Te3 towards high thermoelectric performance
Authors: Pan Yu , Qiu Yang , Witting Ian , Zhang Liguo , Fu Chenguang , Li Jing-Wei , Huang Yi , Sun Fu-Hua , He Jiaqing , Snyder G. Jeffrey , Felser Claudia , Li Jing-Feng
Published: December 2018

Two-step sintering efficiently enhances zT by tuning the microstructure in a wide range from atomic defects to micrometer second phase.