bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Gas Flow Rate on Hydrate Formation Within the Hydrate Stability Zone
Authors: Meyer Dylan W. , Flemings Peter B. , DiCarlo David 
Published: August 2018

AbstractWe form methane hydrate in brine‐saturated, coarse‐grained samples, under hydrate‐stable conditions, by injecting methane vapor at various flow rates. Decreasing the flow rate results in higher hydrate saturation, lower brine saturation, a smaller affected volume, and larger average pressure differentials across the sample. We interpret that the longer execution times at lower flow rates allow for additional methane transport and hydrate formation at the hydrate‐brine interface. As a result, the hydrate skin is thicker at lower flow rates and thus is capable of sustaining larger pressure differentials. In several experiments, we stop brine flow and supply methane gas to the sample for an additional 800 hrs. During this period, hydrate continues to form, pressure differentials develop, and the bulk density changes within the affected volume. We interpret that there is gas present in the sample that is disconnected from the gas source. Hydrate forms around the disconnected gas due to methane transport through the skin that surrounds it, causing the internal gas pressure to decline and leading to inward collapse and net volume decrease. This lowers the brine pressure and creates a differential pressure across the sample that induces gas flow. This study indicates that lower gas flow rates through the hydrate stability zone can produce very high saturations of hydrate but require a larger differential pressure to sustain flow. Ultimately, this process is an alternative mechanism for sustained upward gas flow and hydrate formation far above the base of the hydrate stability zone.
Subannual and Seasonal Variability of Atlantic‐Origin Waters in Two Adjacent West Greenland Fjords
Authors: Carroll D. , Sutherland D. A. , Curry B. , Nash J. D. , Shroyer E. L. , Catania G. A. , Stearns L. A. , Grist J. P. , Lee C. M. , de Steur L. 
Published: August 2018

AbstractGreenland fjords provide a pathway for the inflow of warm shelf waters to glacier termini and outflow of glacially modified waters to the coastal ocean. Characterizing the dominant modes of variability in fjord circulation, and how they vary over subannual and seasonal time scales, is critical for predicting ocean heat transport to the ice. Here we present a 2‐year hydrographic record from a suite of moorings in Davis Strait and two neighboring west Greenland fjords that exhibit contrasting fjord and glacier geometry (Kangerdlugssuaq Sermerssua and Rink Isbræ). Hydrographic variability above the sill exhibits clear seasonality, with a progressive cooling of near‐surface waters and shoaling of deep isotherms above the sill during winter to spring. Renewal of below‐sill waters coincides with the arrival of dense waters at the fjord mouth; warm, salty Atlantic‐origin water cascades into fjord basins from winter to midsummer. We then use Seaglider observations at Davis Strait, along with reanalysis of sea ice and wind stress in Baffin Bay, to explore the role of the West Greenland Current and local air‐sea forcing in driving fjord renewal. These results demonstrate the importance of both remote and local processes in driving renewal of near‐terminus waters, highlighting the need for sustained observations and improved ocean models that resolve the complete slope‐trough‐fjord‐ice system.
Potential Impacts of Sahara Dust Aerosol on Rainfall Vertical Structure Over the Atlantic Ocean as Identified From EOF Analysis
Authors: Dong Xue , Li Rui , Wang Yu , Fu Yunfei , Zhao Chun 
Published: August 2018

AbstractThe current study investigates the potential impacts of Sahara dust on rainfall vertical structure over the Atlantic Ocean by employing multisensor satellite observations. The variabilities in rainfall vertical structure are decomposed by empirical orthogonal function (EOF) analysis. For a given near surface rain rate, the mean storm height of stratiform rain under dust‐laden condition is significantly higher than that under the dust‐free condition. The stratiform rain rate at the layers well above the freezing level is substantially enhanced under dust‐laden condition. Those changes may result from dynamic and thermodynamic effect of Sahara Air Layer effect and/or the effect that dust aerosol acting as additional ice nuclei. For convective rain, there is no significant difference in the leading three normalized EOF modes between the dust‐laden and dust‐free sectors, implying that dust effect, if exists, is not strong enough to cause evident changes in convective rainfall profiles. For stratiform rain, the EOF1 shows no signals of dust effect either. However, significant difference is found in the EOF2 and EOF3 modes between dust‐laden and dust‐free conditions. The normalized EOF2 and EOF3 under dust‐laden condition both represent enhanced rain rate at the upper layer well above the freezing level, where heterogeneous ice nucleation prevails. The statistical study shows consistent results with the case study, except that the aerosol‐related changes in stratiform rainfall vertical structure is isolated in the EOF3 only. This study suggests that EOF analysis is a promising way for isolating the potential and relatively weak aerosol effects on precipitation from the strong dynamic effects.
Circulation‐Conditioned Wintertime Temperature Bias in EURO‐CORDEX Regional Climate Models Over Central Europe
Authors: Lhotka Ondřej , Kyselý Jan 
Published: August 2018

AbstractWe analyze circulation‐conditioned wintertime temperature biases in regional climate models (RCMs) over Central Europe and link them to simulation of cold days. Daily minimum and maximum temperatures from the European Coordinated Regional Climate Downscaling Experiment RCMs are evaluated against reference data from the E‐OBS gridded data set. Flow direction is analyzed through u‐ and v‐wind components at the 850‐hPa pressure level taken from the ERA‐Interim reanalysis. Cloud cover and snow‐area fraction from the same reanalysis are used to associate the temperature biases with physical mechanisms. Distribution of flow directions during cold days is evaluated using efficiency coefficients, calculated as ratios of the relative abundance of flow directions during cold days and their wintertime climatology. RCMs driven by the reanalysis have both positive and negative minimum temperature biases, ranging from +0.7 to −2.7 °C. By contrast, all reanalysis‐driven RCMs have negative maximum temperature biases, especially during northerly and westerly advection, which is probably related to overestimated cloud cover. The too‐cold westerly and northerly flows are associated with an overestimated number of cold days and relatively high values of efficiency coefficients under these directions. Efficiency coefficients are simulated better under southeasterly advection, during which the temperature bias tends to be the lowest. The results suggest that simulated cold events should be analyzed and interpreted with caution, since they may develop also under zonal flow in some models, which contradicts observations.
Characteristics of Lightning Flashes Associated With the Charge Layer Near the 0 °C Isotherm in the Stratiform Region of Mesoscale onvective Systems
Authors: Wang Fei , Liu Hengyi , Dong Wansheng , Zhang Yijun , Meng Qing 
Published: August 2018

AbstractData from an S‐band Doppler radar system and a three‐dimensional very high frequency (VHF) radiation source location system in Chongqing, China, were combined to analyze the characteristics of stratiform lightning flashes associated with the charge layer near the 0 °C isotherm (SL0s) in 10 mesoscale convective systems during the summers of 2014–2015. Most of the SL0 events occurred during the dissipating stage of two thunderstorms. The bright band was found to have a very close relationship with the initiation of the SL0 events. The noninductive and inductive charging mechanisms associated with the process of melting ice particles were inferred to contribute to the charge of the bright band area. The reflectivity at the first located VHF radiation source (FirstS) of the SL0s was always weaker than that in the reflectivity core within the lightning area. The stronger the reflectivity core, the greater the difference between the reflectivity and the reflectivity core. The SL0s generated by the thunderstorms with low SL0 frequency tended to have weaker reflectivity at the FirstS but a stronger reflectivity core in the lightning area than that of the thunderstorms with high SL0 frequency. In the storms with low SL0 frequency, SL0s occurred only when the initiation height of the stratiform lightning flashes decreased gradually toward the height range of the SL0s; but in one storm with high SL0 frequency, the SL0s were generated simultaneously with the stratiform lightning flashes initiated at a high level. It gives a clue that the melting charging mechanisms may enhance the charge density of the bright band area.
Joint Transmitter Selection and Resource Management Strategy Based on Low Probability of Intercept Optimization for Distributed Radar Networks
Authors: Shi C. G. , Wang F. , Salous S. , Zhou J. J. 
Published: August 2018

AbstractIn this paper, a joint transmitter selection and resource management (JTSRM) strategy based on low probability of intercept (LPI) is proposed for target tracking in distributed radar network system. The basis of the JTSRM strategy is to utilize the optimization technique to control transmitting resources of radar networks in order to improve the LPI performance while guaranteeing a specified target‐tracking accuracy. The weighted intercept probability and transmit power of radar networks is defined and subsequently employed as the optimization criterion for the JTSRM strategy. The resulting optimization problem is to minimize the LPI performance criterion of radar networks by optimizing the revisit interval, dwell time, transmitter selection, and transmit power subject to a desired target‐tracking performance and some resource constraints. An efficient and fast three‐step solution technique is also developed to solve this problem. The presented mechanism implements the optimal working parameters based on the feedback information in the tracking recursion cycle in order to improve the LPI performance for radar networks. Numerical simulations are provided to verify the superior performance of the proposed JTSRM strategy.
Detection of Low‐Frequency Continuum Radiation
Authors: Füllekrug Martin , Koh Kuang , Liu Zhongjian , Mezentsev Andrew 
Published: August 2018

AbstractThe electromagnetic spectrum at low frequencies from ∼3 to 300 kHz is dominated by impulses from lightning discharges and anthropogenic radio transmissions used for communication. Electromagnetic waves generated in near‐Earth space exhibit generally smaller amplitudes that are attenuated when travelling through the ionosphere before they can be observed at high and midlatitudes. Electromagnetic waves with yet smaller amplitudes contribute to the overall electromagnetic energy trapped within the Earth‐ionosphere cavity. At this point, the electromagnetic waves from all possible sources blend into an unstructured continuum radiation near the instrumental noise floor, which is often considered to be a fundamental limit to scientific discovery. As a result, the sources of continuum radiation have been little studied and are essentially unknown. Here we show how low‐frequency continuum radiation is detected and discriminated against known radio sources and instrumental noise by use of rigorous criteria inferred from novel precision measurements with an array of radio receivers. In particular, it is found that coherent continuum radiation from intermittent radio transmitters exhibits electric field strengths 0.5–0.7 μV/m, which are almost 2 orders of magnitude smaller when compared to the noise floor of the radio receivers ∼25 μV/m. Another part of the continuum radiation is found at local zenith above the array when it is caused by random instrumental noise. The results exemplify the possibility to extract sources from continuum radiation to study their origin and physical properties, which can contribute to an improved understanding of the impact of space weather and solar variability on the Earth's upper atmosphere.
CircularRNA_104670 plays a critical role in intervertebral disc degeneration by functioning as a ceRNA
Authors: Song Jian , Wang Hong-Li , Song Ke-Han , Ding Zhi-Wen , Wang Hai-Lian , Ma Xiao-Sheng , Lu Fei-Zhou , Xia Xin-Lei , Wang Ying-Wei , Fei-Zou  , Jiang Jian-Yuan 
Published: August 2018

AbstractThis study was carried out to explore the roles of circular RNAs (circRNAs) in nucleus pulposus (NP) tissues in intervertebral disc degeneration (IDD). Differentially expressed circRNAs in IDD and normal NP tissues were identified based on the results of microarray analysis. Bioinformatics techniques were employed to predict the direct interactions of selected circRNAs, microRNAs (miR), and mRNAs. CircRNA_104670 was selected as the target circRNA due to its large multiplier expression in IDD tissues. After luciferase reporter and EGFP/RFP reporter assays, we confirmed that circRNA_104670 directly bound to miR-17-3p, while MMP-2 was the direct target of miR-17-3p. The receiver-operating characteristic (ROC) curve showed that circRNA_104670 and miR-17-3p had good diagnostic significance for IDD (AUC circRNA_104670 = 0.96; AUC miRNA-17-3p = 0.91). A significant correlation was detected between the Pfirrmann grade and expression of circRNA_104670 (r = 0.63; p = 0.00) and miR-17-3p (r = −0.62; p = 0.00). Flow-cytometric analysis and the MTT assay showed that interfering with circRNA_104670 using small interfering RNA (siRNA) inhibited NP cell apoptosis (p < 0.01), and this inhibition was reduced by interfering with miR-17-3p. Interfering with circRNA_104670 suppressed MMP-2 expression and increased extracellular matrix (ECM) formation, which were also reduced by interfering with miR-17-3p. Finally, an MRI evaluation showed that circRNA_104670 inhibition mice had a lower IDD grade compared with control mice (p < 0.01), whereas circRNA_104670 and miRNA-17-3p inhibition mice had a higher IDD grade compared with circRNA_104670 inhibition mice (p < 0.05). CircRNA_104670 is highly expressed in the NP tissues of IDD and acts as a ceRNA during NP degradation.
Hybrid graphene metasurfaces for high-speed mid-infrared light modulation and single-pixel imaging
Authors: Zeng Beibei , Huang Zhiqin , Singh Akhilesh , Yao Yu , Azad Abul K. , Mohite Aditya D. , Taylor Antoinette J. , Smith David R. , Chen Hou-Tong 
Published: August 2018

AbstractDuring the past decades, major advances have been made in both the generation and detection of infrared light; however, its efficient wavefront manipulation and information processing still encounter great challenges. Efficient and fast optoelectronic modulators and spatial light modulators are required for mid-infrared imaging, sensing, security screening, communication and navigation, to name a few. However, their development remains elusive, and prevailing methods reported so far have suffered from drawbacks that significantly limit their practical applications. In this study, by leveraging graphene and metasurfaces, we demonstrate a high-performance free-space mid-infrared modulator operating at gigahertz speeds, low gate voltage and room temperature. We further pixelate the hybrid graphene metasurface to form a prototype spatial light modulator for high frame rate single-pixel imaging, suggesting orders of magnitude improvement over conventional liquid crystal or micromirror-based spatial light modulators. This work opens up the possibility of exploring wavefront engineering for infrared technologies for which fast temporal and spatial modulations are indispensable.
CiRS-7 promotes growth and metastasis of esophageal squamous cell carcinoma via regulation of miR-7/HOXB13
Authors: Li Rui-chao , Ke Shun , Meng Fan-kai , Lu Jun , Zou Xiao-jing , He Zhi-gang , Wang Weng-feng , Fang Ming-hao 
Published: August 2018

AbstractThe circular RNA ciRS-7 has been reported to be involved in the pathogenesis of various tumors, including gastric and colorectal cancer. However, the role of ciRS-7 in esophageal squamous cell carcinoma (ESCC) remains unsolved. In this study, we found that the ciRS-7 expression was significantly upregulated in ESCC cancer tissues compared with matched normal tissues and associated with poor patient survival. Overexpression of ciRS-7 abrogated the tumor-suppressive roles of miR-7 including cell proliferation, migration and invasion in vitro as well as tumor growth and lung metastasis in vivo. Mechanistically, ciRS-7 functioned as the sponge of miR-7 and reactivated its downstream HOXB13-mediated NF-κB/p65 pathway. Conclusively, our findings demonstrate how ciRS-7 induces malignant progression of ESCC and that ciRS-7 may act as a novel prognostic marker and therapeutic target for this lethal disease.
Cbl-b deficiency provides protection against UVB-induced skin damage by modulating inflammatory gene signature
Authors: Singh Tej Pratap , Vieyra-Garcia Pablo A. , Wagner Karin , Penninger Josef , Wolf Peter 
Published: August 2018

AbstractExposure of skin to ultraviolet (UV) radiation induces DNA damage, inflammation, and immune suppression that ultimately lead to skin cancer. However, some of the pathways that regulate these events are poorly understood. We exposed mice to UVB to study its early effects in the absence of Cbl-b, a known suppressor of antitumor immune response in the skin. Cbl-b−/− mice were protected from UV-induced cell damage as shown by the lower number of cyclobutane pyrimidine dimers and sunburn cells in exposed skin compared to wild-type mice. Microarray data revealed that deficiency of Cbl-b resulted in differential expression of genes involved in apoptosis evasion, tumor suppression and cell survival in UV-exposed skin. After UVB, Cbl-b−/− mice upregulated gene expression pattern associated with regulation of epidermal cell proliferation linked to Wnt signaling mediators and enzymes that relate to cell removal and tissue remodeling like MMP12. Additionally, the skin of Cbl-b−/− mice was protected from chronic inflammatory responses and epidermal hyperplasia in a 4-weeks UVB treatment protocol. Overall, our results suggest a novel role for Cbl-b in regulating inflammation and physiologic clearance of damaged cells in response to UVB by modulating inflammatory gene signature.
Mesenchymal stem cells ameliorate hyperglycemia-induced endothelial injury through modulation of mitophagy
Authors: Zhu Wuzheng , Yuan Yujia , Liao Guangneng , Li Lan , Liu Jingping , Chen Younan , Zhang Jie , Cheng Jingqiu , Lu Yanrong 
Published: August 2018

AbstractMitochondrial dysfunction and excessive mitochondrial reactive oxygen species (ROS) are fundamental contributors to endothelial injury in diabetic states. Mesenchymal stem cells (MSCs) have exhibited an extraordinary cytoprotective effect that extends to the modulation of mitochondrial homeostasis. However, the underlying mechanisms have not been clearly defined. Emerging evidence has suggested that mitophagy could counteract mitochondrial-derived oxidative stress through the selective elimination of impaired or dysfunctional mitochondria. Therefore, we investigated whether MSCs could ameliorate high-glucose-induced endothelial injury through the modulation of mitophagy. We observed that exposure of human umbilical vein endothelial cells (HUVECs) to high glucose triggers mitochondrial impairment with excessive mitochondrial fragmentation and ROS generation, loss of membrane potential and reduced ATP production. Furthermore, mitophagy was blunted upon high glucose insult, which accelerated dysfunctional mitochondrial accumulation, initiating the mitochondrial apoptotic pathway and, eventually, endothelial dysfunction. MSCs treatment notably attenuated these perturbations accompanied by an enhancement of Pink1 and Parkin expression, whereas these beneficial effects of MSCs were abolished when either Pink1 or Parkin was knocked down. In aortas of diabetic rats, defective mitophagy was observed, which coincided with marked mitochondrial dysfunction. Ultrastructurally, RAECs from diabetic rats revealed a significant reduction in autophagic vacuoles and a marked increase in fragmented mitochondria. Importantly, the infusion of MSCs restored Pink1/Parkin-mediated mitophagy, ameliorated mitochondrial dysfunction and attenuated apoptosis in endothelial cells in diabetic rats. These results suggest that MSCs may protect endothelial cells from hyperglycemia-induced injury by ameliorating mitochondrial dysfunction via Pink1/Parkin –mediated mitophagy
Nano-sized Al2O3 particle-induced autophagy reduces osteolysis in aseptic loosening of total hip arthroplasty by negative feedback regulation of RANKL expression in fibroblasts
Authors: Li De , Wang Chenglong , Li Zhuokai , Wang Hui , He Jiye , Zhu Junfeng , Zhang Yuehui , Shen Chao , Xiao Fei , Gao Yuan , Zhang Xiang , Li Yang , Wang Peng , Peng Jianping , Cai Guiquan , Zuo Bin , Yang Yuehua , Shen Yun , Song Weidong , Zhang Xiaoling , Shen Lei , Chen Xiaodong 
Published: August 2018

AbstractAseptic loosening is mainly caused by wear debris generated by friction that can increase the expression of receptor activation of nuclear factor (NF)-κB (RANKL). RANKL has been shown to support the differentiation and maturation of osteoclasts. Although autophagy is a key metabolic pathway for maintaining the metabolic homeostasis of cells, no study has determined whether autophagy induced by Al2O3 particles is involved in the pathogenesis of aseptic loosening. The aim of this study was to evaluate RANKL levels in patients experiencing aseptic loosening after total hip arthroplasty (THA) and hip osteoarthritis (hOA) and to consequently clarify the relationship between RANKL and LC3II expression. We determined the levels of RANKL and autophagy in fibroblasts treated with Al2O3 particles in vitro while using shBECN-1 interference lentivirus vectors to block the autophagy pathway and BECN-1 overexpression lentivirus vectors to promote autophagy. We established a novel rat model of femoral head replacement and analyzed the effects of Al2O3 particles on autophagy levels and RANKL expression in synovial tissues in vivo. The RANKL levels in the revision total hip arthroplasty (rTHA) group were higher than those in the hOA group. In patients with rTHA with a ceramic interface, LC3II expression was high, whereas RANKL expression was low. The in vitro results showed that Al2O3 particles promoted fibroblast autophagy in a time- and dose-dependent manner and that RANKL expression was negatively correlated with autophagy. The in vivo results further confirmed these findings. Al2O3 particles induced fibroblast autophagy, which reduced RANKL expression. Decreasing the autophagy level promoted osteolysis and aseptic prosthetic loosening, whereas increasing the autophagy level reversed this trend.