bluuebunny/crossref_metadata_2025 huggingface dataset:
Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions: An ERG Observation
Authors: Kazama Y. , Kojima H. , Miyoshi Y. , Kasahara Y. , Usui H. , Wang B.‐J. , Wang S.‐Y. , Tam S. W. Y. , Chang T.‐F. , Ho P. T. P. , Asamura K. , Kumamoto A. , Tsuchiya F. , Kasaba Y. , Matsuda S. , Shoji M. , Matsuoka A. , Teramoto M. , Takashima T. , Shinohara I.
Published: September 2018

In this study, we describe small‐scale density depletions of cold electrons associated with electrostatic electron cyclotron harmonic (ECH) waves observed by the ERG (Exploration of energization and Radiation in Geospace) spacecraft during a plasmapause crossing near the magnetic equator in the postmidnight sector. The total electron density was roughly 2 orders of magnitude larger than that of the hot electrons, indicating existence of a cold and dense electron population below ∼20 eV. The cold electron density profile showed small‐scale density depletion regions, in which the ECH emissions were intensified. Moreover, a flux enhancement of hot electrons in the perpendicular direction was also associated with the ECH emissions intensity. This relation suggests perpendicular energization of electrons by electric field oscillation of the ECH waves.
Longitudinal Characteristics of Martian Electron Density Profiles: MGS Observations
Authors: Upadhayaya A. K. , Gupta Sumedha
Published: September 2018

An analysis of longitudinal characteristics of 5,600 electron density profiles returned from the Mars Global Surveyor's Radio Science experiment is carried out by dividing the entire data set into 33 subsets, keeping solar zenith angle nearly constant. We find that the peak altitude of the photochemical F1 layer (hmF1) exhibits a large degree of longitudinal variability. This variability is not seen in Earth's ionosphere. Since F1 layer is isobaric, this variability in hmF1 represents a large degree of spatial changes in the underlying neutral atmosphere. Though this variability is quite chaotic in most of the subsets, a few subsets provide some evidence for the presence of a well‐defined wave. We therefore perform a spectral fit of wave 1–3, as earlier carried out by Bougher et al. (2004, https://doi.org/10.1029/2003JE002154; 2001, https://doi.org/10.1029/2001GL012884), to all 33 subsets. Results indicate that this wave is seen only in 10 of the subsets and is most dominant between 0 to 200°E longitudes. Similar wave is seen in the longitude plots of the peak electron density of F1 layer but with a phase reversal. Further, these 10 subsets are confined mostly between 02 to 04 local solar time, thereby indicating a local time dependence of the wave. We examined the characteristics of electron density profiles located at the crests and troughs and found abnormal upliftment in F1 layer during consecutive occultations (~2 hr). Rapid spatial changes are observed during intervals as short as 2 hr. The ionosphere is lifted up and the peak density decreases when wave 1–3 is present.
An Intercomparison of VLF and Sounding Rocket Techniques for Measuring the Daytime D Region Ionosphere: Theoretical Implications
Authors: Siskind D. E. , Zawdie K. A. , Sassi F. , Drob D. P. , Friedrich M.
Published: September 2018

We compare the two approaches that have been used to measure the lowermost ionosphere, the measurement of the propagation of very low frequency (VLF) radio waves and the in situ sampling by sounding rockets. We focus on the altitude, latitude, and zenith angle variation of the electron density profiles inferred from these two observational techniques as compared with a theoretical photochemical model. Our results show that below 68–70 km, the VLF data and the model agree better with each other than with the sounding rocket profile. At the lowest altitudes, near 60 km, both the VLF data and the model show a greater electron density at higher latitudes, consistent with a cosmic ray flux that increases with latitude, whereas the limited rocket data show a maximum at the tropics. Above 68–70 km, the VLF data and the sounding rockets agree better and at tropical latitudes, the model fails to reproduce the observations. Specifically, the calculated electron density is lower than the data by up to a factor of 2. Possible reasons for the model deficit include underestimates of the solar Lyman alpha flux, the solar X‐ray flux and the mesospheric nitric oxide density. Once these three factors are mitigated, the model is in agreement with the observations between 60 and 80 km.
A Modeling Study on the Sensitivities of Atmospheric Charge Separation According to the Relative Diffusional Growth Rate Theory to Nonspherical Hydrometeors and Cloud Microphysics
Authors: Glassmeier F. , Arnold L. , Dietlicher R. , Paukert M. , Lohmann U.
Published: September 2018

Collisional charge transfer between graupel and ice crystals in the presence of cloud droplets is considered the dominant mechanism for charge separation in thunderclouds. According to the relative diffusional growth rate (RDGR) theory, the hydrometeor with the faster diffusional radius growth is charged positively in such collisions. We explore sensitivities of the RDGR theory to nonspherical hydrometeors and six parameters (pressure, temperature, liquid water content, sizes of ice crystals, graupel, and cloud droplets). Idealized simulations of a thundercloud with two‐moment cloud microphysics provide a realistic sampling of the parameter space. Nonsphericity and anisotropic diffusional growth strongly control the extent of positive graupel charging. We suggest a tuning parameter to account for anisotropic effects not represented in bulk microphysics schemes. In a susceptibility analysis that uses automated differentiation, we identify ice crystal size as most important RDGR parameter, followed by graupel size. Simulated average ice crystal size varies with temperature due to ice multiplication and heterogeneous freezing of droplets. Cloud microphysics and ice crystal size thus indirectly determine the structure of charge reversal lines in the traditional temperature‐water‐content representation. Accounting for the variability of ice crystal size and potentially habit with temperature may help to explain laboratory results and seems crucial for RDGR parameterizations in numerical models. We find that the contribution of local water vapor from evaporating rime droplets to diffusional graupel growth is only important for high effective water content. In this regime, droplet size and pressure are the dominant RDGR parameters. Otherwise, the effect of local graupel growth is masked by small ice crystal sizes that result from ice multiplication.
Land‐Atmosphere Coupling in CORDEX‐Africa: Hindcast Regional Climate Simulations
Authors: Careto J. A. M. , Cardoso R. M. , Soares P. M. M. , Trigo R. M.
Published: September 2018

Soil moisture is one of the most important variables of the climate system as it constrains evapotranspiration, affecting the surface energy and water balance. It is of particular importance over transition regions between humid and dry climates as lower evapotranspiration rates lead to higher surface air temperatures thought strong soil moisture‐temperature coupling. A new and more extensive evaluation of the surface energy balance, for the Africa Coordinated Regional Downscaling Experiment, is performed for hindcast simulations, where different Regional Climate Models are driven by ERA‐Interim reanalysis (1990–2008). A new validation is carried out, with Regional Climate Models displaying a good agreement with observations. However, large biases are found over the Sahel and southern Africa for precipitation. All models tend to underestimate maximum temperature, whereas minimum temperature is overestimated for large regions. A multimodel mean ensemble is found to outperform individual models in almost all situations, representing the best estimate of present climate. The seasonal coupling strength as determined by a correlation between latent and sensible heat fluxes indicates Sahel and western Africa as strong coupling for boreal and austral summer, respectively. Also, the strong coupling areas match the transition regions identified by the intermediate values of the evaporative fraction, varying in the spatial extent. Additionally, a new soil moisture‐temperature coupling metric is introduced, which highlights the regions where higher temperatures are influenced by evaporative stress. Therefore, this metric relates extreme daily maximum temperature with latent heat flux and is computed for monthly time scales, incorporating information from the recent past.
Uncertainties in MODIS‐Based Cloud Liquid Water Path Retrievals at High Latitudes Due to Mixed‐Phase Clouds and Cloud Top Height Inhomogeneity
Authors: Khanal Sujan , Wang Zhien
Published: September 2018

Combined A‐train remote sensing measurements from Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR‐E), CloudSat, and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used to study MODIS liquid water path (LWP) uncertainties at high latitudes. The focus is on quantifying uncertainties due to mixed‐phase clouds and solar zenith angle‐dependent bias, both of which disproportionately affect the MODIS data set in the polar regions. Multisensor LWP retrievals in stratiform mixed‐phase clouds show that treating mixed‐phase clouds as liquid clouds result in LWP bias that is related to the ice water path (IWP) on average and reaches close to 15% at IWP of 150 g/m2 and can reach 40% or higher when IWP is greater than 400 g/m2. Moreover, A‐train measurements and radiative transfer modeling are used to further understand the well‐known yet unresolved solar zenith angle‐dependent high bias in MODIS LWP. It is shown that the cloud top height variation is one of the main factors that contribute to this bias due to three‐dimensional radiative interactions with cloud top inhomogeneity. Excluding only 0.5% of data points that show significant three‐dimensional errors reduces the bias by 25 g/m2 at solar zenith angle of 80° and improves agreement with the AMSR‐E LWP trends. Three‐dimensional radiative transfer simulations confirm that cloud top inhomogeneity is primarily responsible for the solar zenith angle‐dependent LWP bias as observed by the MODIS measurements. This study provides a framework to guide future improvements of MODIS LWP data set, which is a key data source to constrain climate models.
Biological Cycling of Mineral Nutrients in a Temperate Forested Shale Catchment
Authors: Soper Fiona M. , Chamberlain Samuel D. , Crumsey Jasmine M. , Gregor Sonia , Derry Louis A. , Sparks Jed P.
Published: September 2018

Biological pumping of mineral elements (root uptake from the soil and concentration at the surface via litterfall) may be an important mechanism influencing their loss from terrestrial ecosystems by accelerating transport in runoff, though few estimates exist to assess this. In the Susquehanna Shale Hills Critical Zone Observatory (a temperate forested watershed in central Pennsylvania), we compared two independent methods (litterfall‐based and transpiration flow‐based) for estimating the total uptake of elements (Ca, K, Mg, Mn, Si, Sr, and Al) by canopy trees. Elemental concentrations were measured monthly in leaf tissue and xylem sap of dominant species Quercus rubra (chestnut oak), Q. prinus (red oak), and Acer saccharum (sugar maple) for two growing seasons. Species‐specific litterfall and transpiration (estimated by eddy covariance) were used to scale concentrations to annual fluxes. For most elements, both methods generated comparable gross fluxes in the range of 53–85 (Ca), 9–19 (Mg), 14–28 (Mn), 0.2–0.6 (Al), and 0.1–0.3 (Sr) kg·ha−1·year−1. For K, litterfall‐based methods generated substantially lower estimates than transpiration, though neither accounted comprehensively for leaching from live foliage, resorption, or potential recycling within the growing season. For most elements, uptake rates were similar in magnitude to stream losses, implying a low degree of recycling. For K and Mn however, biological uptake exceeded losses by 1–2 orders of magnitude, suggesting a biological role in ecosystem retention. We conclude that litter‐ and transpiration‐based methods can be combined to broadly estimate the magnitude of biological pumping, with additional measures of wood‐/root‐based turnover necessary for more accurate budgets.
Solar Sources of Interplanetary Magnetic Clouds Leading to Helicity Prediction
Authors: Ulrich Roger K. , Riley Pete , Tran T.
Published: September 2018

This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We started with the magnetic clouds listed by the Magnetic Field Investigation (MFI) team supporting NASA's Wind spacecraft in what is known as the MFI table and worked backward in time to identify solar events that produced these clouds. Our methods utilize magnetograms from the Helioseismic and Magnetic Imager instrument on the Solar Dynamics Observatory spacecraft so that we could only analyze MFI entries after the beginning of 2011. This start date and the end date of the MFI table gave us 37 cases to study. Of these we were able to associate only eight surface events with clouds detected by Wind at 1 AU. We developed a simple algorithm for predicting the cloud helicity that gave the correct handedness in all eight cases. The algorithm is based on the conceptual model that an ejected flux tube has two magnetic origination points at the positions of the strongest radial magnetic field regions of opposite polarity near the places where the ejected arches end at the solar surface. We were unable to find events for the remaining 29 cases: lack of a halo or partial halo coronal mass ejection in an appropriate time window, lack of magnetic and/or filament activity in the proper part of the solar disk, or the event was too far from disk center. The occurrence of a flare was not a requirement for making the identification but in fact flares, often weak, did occur for seven of the eight cases.
Interpretation of Low‐Temperature Thermochronometer Ages From Tilted Normal Fault Blocks
Authors: Johnstone S. A. , Colgan J. P.
Published: September 2018

Low‐temperature thermochronometry is widely used to measure the timing and rate of slip on normal faults. Rates are often derived from suites of footwall thermochronometer samples, but regression of age versus structural depth fails to account for the trajectories of samples during fault slip. We demonstrate that in rotating fault blocks, regression of age‐depth data is susceptible to significant errors (>10%) in the identification of the initiation and rate of faulting. Advection of heat and topographic growth influence the thermal histories of exhumed particles, but for a range of geologically reasonable fault geometries and rates these effects produce Apatite (U‐Th)/He ages comparable to those derived from rotation through fixed isotherms. We apply the fixed‐isotherm model to published data from the Pine Forest Range and the East Range, Nevada, by incorporating field and thermochronologic constraints into a Markov chain Monte Carlo model. Modeled parameters for the Pine Forest Range are described by narrow ranges of geologically reasonable values. Compared to slip rates of 0.3–0.8 km/Myr and an initiation of faulting ca. 11–12 Ma derived from visual inspection, the model predicts an average slip rate of ~1.1 km/Myr and an onset of faulting ca. 9–10 Ma. For the East Range fault block the model suggests that faulting began ~17 Ma with an extension rate of ~3 km/Myr and slowed to an extension rate of ~0.5 km/Myr at ~14 Ma. The absence of a preserved partial retention zone in the East Range sample set limits how well the model can predict fault block geometry.
Nested Scales of Spatial and Temporal Variability of Soil Water Content Across a Semiarid Montane Catchment
Authors: Kaiser Kendra E. , McGlynn Brian L.
Published: September 2018

Topographic redistribution of water has been represented by various terrain metrics (e.g., topographic wetness index, slope, and upslope accumulated area). This type of landscape characterization has promoted the use of terrain metrics to inform how spatial patterns of soil volumetric water content (VWC) influence streamflow, ecological processes, and associated nutrient fluxes. However, evaluation of what these static terrain metrics reflect has only been accomplished in a few catchments. Additionally, previous research suggests that relationships between topographic metrics and VWC could be different across catchments through time. Here we measured VWC from snowmelt through summer drydown across a semiarid montane catchment. Using a spatially nested sampling design, we assessed the spatiotemporal variability of VWC from plot (tens of meters) to landscape scales (hundreds of meters). Variance of riparian area VWC increased as the catchment dried, while upland variance decreased, highlighting the utility of delineating distinct landscape units when considering spatial variability of moisture, rather than calculating statistics across the landscape as a whole. In contrast to previous research, we found that the relationship between VWC and topographic metrics persisted through the dry catchment state, suggesting that patterns of topographic redistribution of water during snowmelt continued to influence dry season VWC despite variability in plot scale vertical processes (e.g., evapotranspiration). Future research should focus on resolving the relationship between catchment moisture state and VWC variability as a function of wetness state, seasonality, and magnitude of precipitation, topography, and soil depth.
Autism, Early Psychosis, and Social Anxiety Disorder: a transdiagnostic examination of executive function cognitive circuitry and contribution to disability
Authors: Demetriou Eleni A. , Song Christine Y. , Park Shin H. , Pepper Karen L. , Naismith Sharon L. , Hermens Daniel F. , Hickie Ian B. , Thomas Emma E. , Norton Alice , White Django , Guastella Adam J.
Published: September 2018

The disability burden in clinical cohorts with social impairment is significant, leading to poor functional outcomes. Some of this impairment has been linked to executive dysfunction. In this study, a transdiagnostic approach was taken to identify executive function (EF) processes in young adults that may underpin social impairment and to evaluate their contribution to disability. Comparisons were made between three prominent disorders that are characterized by social impairments, Autism Spectrum Disorder (ASD), Early Psychosis (EP) and Social Anxiety Disorder (SAD), as well as a neurotypically developing group (TYP). We examined whether overall disability could be predicted by neuropsychological and self-report assessments of EF. Our study showed that ASD participants demonstrated impaired performance on most domains of EF compared to the TYP group (mental flexibility, sustained attention and fluency) while the EP group showed impairment on sustained attention and attentional shifting. The SAD participants showed EF impairment on self-report ratings, even though their objective performance was intact. Self-reports of EF explained a significant percentage (17%) of disability in addition to the variance explained by other predictors, and this was particularly important for ASD. This is the first study to compare EF measures across clinical groups of social impairment and suggests unique cognitive-circuitry that underpins disability within groups. Impairments in EF were broad in ASD and predicted disability, EP impairments were specific to attentional processes and SAD impairments likely relate to negative self-monitoring. Self-report, as opposed to performance-based EF, provided best capacity to predict disability. These findings contribute to transdiagnostic circuitry models and intervention strategies.
The proline–arginine repeat protein linked to C9-ALS/FTD causes neuronal toxicity by inhibiting the DEAD-box RNA helicase-mediated ribosome biogenesis
Authors: Suzuki Hiroaki , Shibagaki Yoshio , Hattori Seisuke , Matsuoka Masaaki
Published: September 2018

A GGGGCC repeat expansion in the C9ORF72 gene has been identified as the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. The repeat expansion undergoes unconventional translation to produce dipeptide repeat (DPR) proteins. Although it has been reported that DPR proteins cause neurotoxicity, the underlying mechanism has not been fully elucidated. In this study, we have first confirmed that proline–arginine repeat protein (poly-PR) reduces levels of ribosomal RNA and causes neurotoxicity and found that the poly-PR-induced neurotoxicity is repressed by the acceleration of ribosomal RNA synthesis. These results suggest that the poly-PR-induced inhibition of ribosome biogenesis contributes to the poly-PR-induced neurotoxicity. We have further identified DEAD-box RNA helicases as poly-PR-binding proteins, the functions of which are inhibited by poly-PR. The enforced reduction in the expression of DEAD-box RNA helicases causes impairment of ribosome biogenesis and neuronal cell death. These results together suggest that poly-PR causes neurotoxicity by inhibiting the DEAD-box RNA helicase-mediated ribosome biogenesis.
Biased signaling downstream of epidermal growth factor receptor regulates proliferative versus apoptotic response to ligand
Authors: Ali Remah , Brown Wells , Purdy Stephen Connor , Davisson V. Jo , Wendt Michael K.
Published: September 2018

Inhibition of epidermal growth factor receptor (EGFR) signaling by small molecule kinase inhibitors and monoclonal antibodies has proven effective in the treatment of multiple cancers. In contrast, metastatic breast cancers (BC) derived from EGFR-expressing mammary tumors are inherently resistant to EGFR-targeted therapies. Mechanisms that contribute to this inherent resistance remain poorly defined. Here, we show that in contrast to primary tumors, ligand-mediated activation of EGFR in metastatic BC is dominated by STAT1 signaling. This change in downstream signaling leads to apoptosis and growth inhibition in response to epidermal growth factor (EGF) in metastatic BC cells. Mechanistically, these changes in downstream signaling result from an increase in the internalized pool of EGFR in metastatic cells, increasing physical access to the nuclear pool of STAT1. Along these lines, an EGFR mutant that is defective in endocytosis is unable to elicit STAT1 phosphorylation and apoptosis. Additionally, inhibition of endosomal signaling using an EGFR inhibitor linked to a nuclear localization signal specifically prevents EGF-induced STAT1 phosphorylation and cell death, without affecting EGFR:ERK1/2 signaling. Pharmacologic blockade of ERK1/2 signaling through the use of the allosteric MEK1/2 inhibitor, trametinib, dramatically biases downstream EGFR signaling toward a STAT1-dominated event, resulting in enhanced EGF-induced apoptosis in metastatic BC cells. Importantly, combined administration of trametinib and EGF also facilitated an apoptotic switch in EGFR-transformed primary tumor cells, but not normal mammary epithelial cells. These studies reveal a fundamental distinction for EGFR function in metastatic BC. Furthermore, the data demonstrate that pharmacological biasing of EGFR signaling toward STAT1 activation is capable of revealing the apoptotic function of this critical pathway.
AIMP3 depletion causes genome instability and loss of stemness in mouse embryonic stem cells
Authors: Kim Sun Mi , Jeon Yoon , Kim Doyeun , Jang Hyonchol , Bae June Sung , Park Mi Kyung , Kim Hongtae , Kim Sunghoon , Lee Ho
Published: September 2018

Aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3) is a component of the multi-aminoacyl-tRNA synthetase complex and is involved in diverse cellular processes. Given that AIMP3 deficiency causes early embryonic lethality in mice, AIMP3 is expected to play a critical role in early mouse development. To elucidate a functional role of AIMP3 in early mouse development, we induced AIMP3 depletion in mouse embryonic stem cells (mESCs) derived from blastocysts ofAIMP3f/f; CreERT2mice. In the present study, AIMP3 depletion resulted in loss of self-renewal and ability to differentiate to three germ layers in mESCs. AIMP3 depletion led to accumulation of DNA damage by blocking double-strand break repair, in particular homologous recombination. Through microarray analysis, the p53 signaling pathway was identified as being activated in AIMP3-depleted mESCs. Knockdown of p53 rescued loss of stem cell characteristics by AIMP3 depletion in mESCs. These results imply that AIMP3 depletion in mESCs leads to accumulation of DNA damage and p53 transactivation, resulting in loss of stemness. We propose that AIMP3 is involved in maintenance of genome stability and stemness in mESCs.
GRP75 modulates oncogenic Dbl-driven endocytosis derailed via the CHIP-mediated ubiquitin degradation pathway
Authors: Niu Xiuran , Su Linjia , Qi Shanshan , Gao Zhihui , Zhang Qing , Zhang Sihe
Published: September 2018

Chaperone-assisted proteasome degradation of oncogenic protein acts as an upstream signal controlling tumorigenesis and progression. The understanding of the co-regulation of chaperone and oncoprotein of endocytosis pathways is extremely limited. In this study, we showed for the first time that proto-Dbl (dbl proto-oncogene product) is co-enriched with mitochondrial chaperone GRP75 in endocytosis vesicles from ovarian cancer cells. onco-Dbl, produced by oncogenic mutation/degradation of proto-Dbl, markedly enhanced cellular macropinocytosis but suppressed clathrin-mediated endocytosis and clathrin-independent endocytosis pathways, presenting a derailed endocytosis phenotype. GRP75 was associated with proto-Dbl inside cells and modulated Dbl-driven endocytosis derailed by a co-regulatory mode. In spite of not being a component of the Hsc70/Hsp90/proto-Dbl complex, the degradation of proto-Dbl was promoted by GRP75 through the CHIP-mediated ubiquitin–proteasome pathway, of which GRP75 acts as a cooperator with CHIP but also acts as a competitor to Hsc70 and Hsp90 in the multiple chaperones-assisted pro-folding/pro-degradation machinery. Knockdown or inhibition of GRP75 attenuated proto-Dbl degradation and reduced the onco-Dbl level, which differentially impaired Rho GTPases activation and therefore shifted the endocytosis-derailed phenotype. Our data uncovered a novel GRP75-Dbl endocytosis regulatory axis and provided an alternative using chaperone inhibitor to shut down the oncoprotein-driven endocytosis derailment mechanism.
RIPK1 is a critical modulator of both tonic and TLR-responsive inflammatory and cell death pathways in human macrophage differentiation
Authors: Buchrieser Julian , Oliva-Martin Maria Jose , Moore Michael D. , Long Joshua C. D. , Cowley Sally A. , Perez-Simón Jose Antonio , James William , Venero Jose Luis
Published: September 2018

In this study, we took advantage of human-induced pluripotent stem cells (hiPSC) and CRISPR/Cas9 technology to investigate the potential roles of RIPK1 in regulating hematopoiesis and macrophage differentiation, proinflammatory activation, and cell death pathways. Knock-out of RIPK1 in hiPSCs demonstrated that this protein is not required for erythro-myeloid differentiation. Using a well-established macrophage differentiation protocol, knock-out of RIPK1 did not block the differentiation of iPSC-derived macrophages, which displayed a similar phenotype to WT hiPSC-derived macrophages. However, knock-out of RIPK1 leads to a TNFα-dependent apoptotic death of differentiated hiPSC-derived macrophages (iPS-MΦ) and progressive loss of iPS-MΦ production irrespective of external pro-inflammatory stimuli. Live video analysis demonstrated that TLR3/4 activation of RIPK1 KO hiPSC-derived macrophages triggered TRIF and RIPK3-dependent necroptosis irrespective of caspase-8 activation. In contrast, TLR3/4 activation of WT macrophages-induced necroptosis only when caspases were inhibited, confirming the modulating effect of RIPK1 on RIPK3-mediated necroptosis through the FADD, Caspase-8 pathway. Activation of these inflammatory pathways required RIPK3 kinase activity while RIPK1 was dispensable. However, loss of RIPK1 sensitizes macrophages to activate RIPK3 in response to inflammatory stimuli, thereby exacerbating a potentially pathological inflammatory response. Taken together, these results reveal that RIPK1 has an important role in regulating the potent inflammatory pathways in authentic human macrophages that are poised to respond to external stimuli. Consequently, RIPK1 activity might be a valid target in the development of novel therapies for chronic inflammatory diseases.
Impacts of surfactants on dissolution and sulfidation of silver nanowires in aquatic environments
Authors: Zhang Yinqing , Xia Junchao , Xu Jinliang , Sun Binbin , Wu Wei , Zhu Lingyan
Published: September 2018

Cationic surfactants could facilitate the oxidative dissolution and sulfidation of AgNWs, and may reduce their toxicity to aquatic organisms.
Gd3+-Ion-induced carbon-dots self-assembly aggregates loaded with a photosensitizer for enhanced fluorescence/MRI dual imaging and antitumor therapy
Authors: Liu Yanlei , Zhi Xiao , Hou Wenxiu , Xia Fangfang , Zhang Jingpu , Li Lexiang , Hong Yuping , Yan Hao , Peng Chen , de la Fuentea Jesus Martinez , Song Jie , Cui Daxiang
Published: September 2018

The development of multifunctional nanoparticles for tumor theranostics has become a research hotspot.
A synergistic vertical graphene skeleton and S–C shell to construct high-performance TiNb2O7-based core/shell arrays
Authors: Shen Shenghui , Guo Weihao , Xie Dong , Wang Yadong , Deng Shengjue , Zhong Yu , Wang Xiuli , Xia Xinhui , Tu Jiangping
Published: September 2018

Binder-free VG/TiNb2O7@S–C electrodes prepared via a powerful solvothermal-electrodeposition (ST-ED) method show good high-rate performance (241 mA h g−1/70 °C at 160C) and long high-temperature lifespan (>5000 cycles) at medium–high temperatures.
A high temperature stable piezoelectric strain of KNN-based ceramics
Authors: Cen Zhenyong , Huan Yu , Feng Wei , Yu Yan , Zhao Peiyao , Chen Lingling , Zhu Chaoqiong , Li Longtu , Wang Xiaohui
Published: September 2018

Lead-free (1 − x)(0.96K0.46Na0.54Nb0.98Ta0.02O3–0.04Bi0.5(Na0.82K0.18)0.5ZrO3)–xCaZrO3 ((1 − x)(0.96KNNT–0.04BNKZ)–xCZ) piezoelectric ceramics were prepared by the conventional solid-state reaction method.
Graphical two‐term control system design considering time delay margin and time‐integral performance criterion
Authors: Emirler M.T.
Published: September 2018

A graphical control system design approach is proposed in this Letter considering time delay margin and time‐integral performance criterion. For two free design parameters, time delay margin boundaries are plotted into 2D parameter plane by using parameter space approach. The details of obtaining design equations are introduced. A time‐integral error criterion is calculated for gridded design parameters and shown on the same plot to obtain contour curve representation of the error values. An application example is selected from automotive control literature to test the effectiveness of the proposed approach with simulations. Simulation results are obtained for different benchmark controllers and compared with each other in terms of time domain step response characteristics and error values.
Articulated deformable structure approach to human motion segmentation and shape recovery from an image sequence
Authors: Zhang Peter Boyi , Hung Yeung Sam
Published: September 2018

The aim of this study is to perform motion segmentation and three‐dimensional shape recovery of a dynamic human body from an image sequence. The authors note that human body motion generally consists of large articulations between different body parts and small local deformations within each body part. On the basis of this notion, they develop an integrated framework that combines articulated structure from motion and non‐rigid SFM to estimate human body motion and shape as an articulated deformable structure. Unlike existing approaches that apply a low‐rank subspace method for motion segmentation, they use a metric constraint for identifying rigid subsets, which is more robust and, therefore, allow a more relaxed error threshold to be set for fitting rigid subsets, catering for small deformations within individual rigid subsets. They provide an automated statistical procedure for setting the aforementioned error threshold. The rigid subsets are then linked into articulated kinematic chains by minimum spanning tree search in a graph of joint costs. Finally, the blend‐shape method is applied to model local deformations of each individual subset. Experimental results show that the proposed method provides better performance for human motion segmentation and shape recovery compared with existing methods.
Single phase nine level inverter using single DC source supported by capacitor voltage balancing algorithm
Authors: Sekar Rathinam Marimuthu , Nelson Jayakumar Dhanaraj , Mylsamy Kaliamoorthy , Subramaniam Umashankar , Padmanaban Sanjeevikumar
Published: September 2018

This study introduces a new single phase nine‐level inverter using two capacitors and a single DC source. Voltage imbalances in the capacitors are eliminated using two control algorithms namely charging algorithm and discharging algorithm. The charging algorithm is used to change the inverter switching states when the measured voltage across the capacitors is less than the prescribed value. Alternatively, if the voltage across the capacitors is greater than the set value, the discharging algorithm determines the switching pattern of the inverter switches. The proposed voltage balancing algorithm is very simple to implement and makes the proposed inverter attractive for industrial applications. An extensive comparison of the proposed inverter is made against other topologies proposed in the literature in terms of the components used. The proposed inverter is tested in both standalone and grid connected modes. The proposed inverter is simulated and implemented as a prototype in the laboratory. Experimental results obtained from the prototype confirm the high‐quality transient performance of the proposed inverter in terms of its dc capacitor voltage balancing capability.
Analysis and experimentation of the quad‐U variable inductor for power electronics applications
Authors: Alonso José Marcos , Perdigão Marina , Dalla Costa Marco Antonio , Zhang Shu , Wang Yijie
Published: September 2018

In this study, the analysis of the quad‐U variable inductor (VI) is presented. This is an alternative structure of VI to other ones previously presented and analysed in the literature, as for example the double‐E structure and the triple‐E structure. Compared to them, the quad‐U structure shows some advantages, namely more symmetrical operation and zero voltage reflected across the bias winding. The superposition law is applied to the equivalent reluctance model in order to solve for DC and AC operation separately. Using the proposed methodology, both AC winding inductance and DC winding inductance can be obtained. An example of analysis is presented for a particular quad‐U VI. Simulation and experimental results prove the validity of the proposed analysis and modelling methodology.
Study on subsynchronous oscillation in D‐PMSGs‐based wind farm integrated to power system
Authors: Huang Biyue , Sun Haishun , Liu Yuming , Wang Long , Chen Yahao
Published: September 2018

In recent years, the subsynchronous oscillation (SSO), which occurs in direct‐drive permanent magnetic synchronous generators (D‐PMSGs)‐based wind farm, has great impact on the stability of power system. The different parameters and operation conditions of D‐PMSGs lead to the subsynchronous interaction (SSI) among D‐PMSGs. What is more, the SSI will influence the SSO characteristics of the system of D‐PMSGs‐based wind farm integrated to AC network. Here, considering the difference of parameters or operation conditions among D‐PMSGs in the wind farm, eigenvalue analysis, based on the small‐signal state‐space model of two aggregated D‐PMSGs which are equivalent to wind farm, is carried out. Then the stability and the SSI between D‐PMSGs of the equivalent system can be studied, and the dominant D‐PMSG can be determined based on the participation factors. Lastly, the detailed electromagnetic transient simulation model of D‐PMSGs equivalent system is built in PSCAD/EMTDC. The simulation is conducted to corroborate the eigenvalue analysis. The result shows that an obvious SSI exists between two aggregated D‐PMSGs. Furthermore, the different SSO characteristics among D‐PMSGs in the wind farm indicate the study of SSO problem based on an aggregated D‐PMSGs model may leave out some useful information.
Maximum power point tracking technique using artificial bee colony and hill climbing algorithms during mismatch insolation conditions on PV array
Authors: Goud J Saikrishna , R. Kalpana , Singh Bhim , Kumar Shailendra
Published: September 2018

This study presents a single current sensor based hybrid maximum power point tracking method to track the global maximum power point (GMPP) of the photovoltaic (PV) array during the mismatch insolation conditions. This method combines the artificial bee colony (ABC) and hill climbing (HC) algorithms to track the GMPP of a PV array. The proposed method uses the HC algorithm to identify the occurrence of mismatch insolation conditions on PV array. During the mismatch insolation conditions, the proposed method scans the battery charging current (Icharge) versus duty cycle (D) characteristics of the power electronic interface circuit to classify the type of shading pattern of P–V curve and also to identify the vicinity of the GMPP. Based on the kind of shading pattern of a P–V curve, the proposed method operates either ABC or HC algorithm to track the GMPP. To improve the convergence speed of the proposed method, the search space of the ABC algorithm is reduced. The proposed method is modelled and simulated in MATLAB software and its performance is validated experimentally for various mismatch insolation conditions.
Impacts of wind power forecast errors on the real‐time balancing need: a Nordic case study
Authors: Miettinen Jari , Holttinen Hannele
Published: September 2018

As the share of wind power increases in the power system, also the share of uncertain generation increases. This, in turn, increases the total balancing energy, real‐time balancing power requirements and ramping of the balancing generation. In this study, the impact of wind power forecast errors on the real‐time balancing need was investigated for different shares of wind energy (4–30%) in Finland and the Nordic region (comprising Denmark, Finland, Norway and Sweden). The size of the aggregation area of the net imbalances has an impact on the net imbalance volumes. The larger the size of the area is, the smaller the normalised net imbalance volumes are. In Finland, the impact of wind forecast errors on the net imbalance volumes and the largest net imbalances is almost two times as large as the impact of wind power forecast errors in the Nordic region. A shorter forecast horizon has an impact of similar magnitude both on reducing the net imbalance volumes and the largest net imbalances and on aggregating imbalances from large spatial areas. When day‐ahead forecasts are not corrected intraday (ID) the impact on the net imbalance volumes and the largest net imbalances is twice as large as when ID forecasts are used.
Energy management in smart grids for the integration of hybrid wind–PV–FC–battery renewable energy resources using multi‐objective particle swarm optimisation (MOPSO)
Authors: Elgammal Adel , El‐Naggar Mohamed
Published: September 2018

This study introduces an efficient energy management system (EMS) for a wind–photovoltaic (PV)–fuel cell (FC)–battery energy scheme with an effective control strategy to integrate with the utility grid. The suggested technique utilises the multi‐objective particle swarm optimisation (MOPSO) to minimise the operation cost of the microgrid (MG) and maximise the generated power by each source. The presented MOPSO has the ability to minimise the operation cost of the MG with respect to the renewable penetration, the fluctuation in the generated power, uncertainty in power demand, and continuous change of the utility market price. The proposed optimisation strategy makes the exact choice of sources in right planning and chooses the power that must be created by each source and the power required by the utility network. The price fluctuation data of power and the variance of the renewable energy produced by each unit will be sent to the EMS by a communication network using global positioning system. The dynamic performance and the operation cost of the MG have been tested under different weather conditions and the variance of the power demand through a whole simulation period of 24 h. The stability of the MG, power quality, and voltage regulation is verified by Matlab simulation and experimental results.
Granularity reduction method based on positive decision holding for multi‐granulation decision‐theoretic rough set
Authors: Chen Jiajun , Huang Yuanyuan , Wei Wenjie , Shi Zhongrong
Published: September 2018

Multi‐granulation decision‐theoretic rough set (MG‐DTRS) is a generalisation of the multi‐granulation rough set (MGRS) model through integrating the related properties of MGRSs and decision‐theoretic rough sets (DTRSs), and it can realise decision analysis and processing of information systems from multiple perspectives and multi‐level. Taking the optimistic MG‐DTRS and the pessimistic MG‐DTRS model as an example, MG‐DTRS model and its related properties were discussed according to the DTRSs which construct positive, boundary and negative regions on the basis of two thresholds given by experts. Especially, the positive decision and its properties in MG‐DTRS model were analysed. At the same time, it was found and proved that the positive decision is monotonic with the change of granularity in MG‐DTRS model. Further, the granular structure selection problem was investigated under the MG‐DTRS model, the concept of α‐decision granularity importance was introduced and a granularity reduction algorithm based on the positive decision holding for MG‐DTRS model was designed and constructed. Finally, an example was given to prove that the algorithm is effective, and it has a small time complexity.
Method to control flux balancing of high‐frequency transformers in dual active bridge dc–dc converters
Authors: Wang Zitan , Chai Jianyun , Sun Xudong
Published: September 2018

Due to non‐ideal behaviours and switching characteristics, dc bias might be generated in the dual active bridge converters. It could be more serious in the high‐frequency transformers because of small loop resistances. It could also restrict the range of operating flux density due to the threat of saturation. This study analyses the steady‐state dc bias and divides it into two categories. Then an active flux‐balancing control method is proposed to eliminate these dc biases. It uses separate proportional integral controls and adjusts duty ratios of both sides independently to achieve flux balance. A generalised average model is established to verify its dynamic performance and stability. Simulation and experimental verification on a laboratory prototype confirm the performance of this approach.
Operation strategy of energy hub for commercial buildings based on tiered temperature control
Authors: Li Yinglan
Published: September 2018

In this study, the author considers an operation strategy of energy hubs for commercial buildings based on tiered temperature control, with the objective of balancing the operation cost and comfort level. A tiered temperature deviation penalty tariff is formulated to measure different levels of temperature deviation. Considering a set of uncertain factors, including photovoltaic output, load demand and outside temperature, this stochastic optimisation model can be converted into a mixed‐integer linear program, solved by commercial optimisation solver, CPLEX. Numerical simulations verify the efficiency of the proposed operation strategy.
Analytics of high‐penetration renewable energy accommodation using power system operation simulation
Authors: Tian Xin , Zhang Jian , Li Xueliang , Zhao Long , Wu Jian
Published: September 2018

In recent years, China's renewable energy has developed rapidly. The installed capacity of wind power and photovoltaic power has ranked first in the world. While at the same time, China is also facing a serious problem of curtailment of wind and photovoltaic energy. In this study, the statistical characteristics of high‐penetration renewable energy accommodation were analysed using power system operation simulation. The sensitivity of the bottleneck is quantified based on the operation simulation results. The contribution degrees of peak regulation and transmission capacity are analysed using the proposed metrics. Finally, the proposed methods are used to analyse the characteristics of renewable energy accommodation in a provincial power grid of China in the scenario of 2020.
Convolutional sequence to sequence non‐intrusive load monitoring
Authors: Chen Kunjin , Wang Qin , He Ziyu , Chen Kunlong , Hu Jun , He Jinliang
Published: September 2018

A convolutional sequence to sequence non‐intrusive load monitoring model is proposed in this study. Gated linear unit convolutional layers are used to extract information from the sequences of aggregate electricity consumption. Residual blocks are also introduced to refine the output of the neural network. The partially overlapped output sequences of the network are averaged to produce the final output of the model. The authors apply the proposed model to the reference energy disaggregation data set dataset and compare it with the convolutional sequence to point model in the literature. Results show that the proposed model is able to give satisfactory disaggregation performance for appliances with varied characteristics.
TFAW: Wavelet-based signal reconstruction to reduce photometric noise in time-domain surveys
Authors: del Ser D. , Fors O. , Núñez J.
Published: September 2018

Context. There have been many efforts to correct systematic effects in astronomical light curves to improve the detection and characterization of planetary transits and astrophysical variability. Algorithms such as the trend filtering algorithm (TFA) use simultaneously-observed stars to measure and remove systematic effects, and binning is used to reduce high-frequency random noise.

Aims. We present TFAW, a wavelet-based modified version of TFA. First, TFAW aims to increase the periodic signal detection and second, to return a detrended and denoised signal without modifying its intrinsic characteristics.

Methods. We modified TFA’s frequency analysis step adding a stationary wavelet transform filter to perform an initial noise and outlier removal and increase the detection of variable signals. A wavelet-based filter was added to TFA’s signal reconstruction to perform an adaptive characterization of the noise- and trend-free signal and the underlying noise contribution at each iteration while preserving astrophysical signals. We carried out tests over simulated sinusoidal and transit-like signals to assess the effectiveness of the method and applied TFAW to real light curves from TFRM. We also studied TFAW’s application to simulated multiperiodic signals.

Results. TFAW improves the signal detection rate by increasing the signal detection efficiency (SDE) up to a factor ∼2.5× for low S/R light curves. For simulated transits, the transit detection rate improves by a factor ∼2 − 5× in the low-S/R regime compared to TFA. TFAW signal approximation performs up to a factor ∼2× better than bin averaging for planetary transits. The standard deviations of simulated and real TFAW light curves are ∼40% better compared to TFA. TFAW yields better MCMC posterior distributions and returns lower uncertainties, less biased transit parameters and narrower (by approximately ten times) credibility intervals for simulated transits. TFAW is also able to improve the characterization of multiperiodic signals. We present a newly-discovered variable star from TFRM.