bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Irradiation on Mechanical and Thermal Properties of Selected Types of Polymers
Authors: Manas David , Ovsik Martin , Mizera Ales , Manas Miroslav , Hylova Lenka , Bednarik Martin , Stanek Michal
Published: February 2018

This article deals with the influence of electron-beam radiation on the micro-mechanical, thermo-mechanical, and structural properties of selected polymers. In the search for the desired improvement of polymers, it is possible to use, inter alia, one particular possible modification—Namely, crosslinking—Which is a process during which macromolecular chains start to connect to each other and, thus, create the spatial network in the structure. In the course of the treatment of the ionizing radiation, two actions can occur: crosslinking and scission of macromolecules, or degradation. Both these processes run in parallel. Using the crosslinking technology, standard and technical polymers can acquire the more “expensive” high-tech polymeric material properties and, thus, replace these materials in many applications. The polymers that were tested were selected from across the whole spectra of thermoplastics, ranging from commodity polymers, technical polymers, as well as high-performance polymers. These polymers were irradiated by different doses of beta radiation (33, 66, 99, 132, 165, and 198 kGy). The micro-mechanical and thermo-mechanical properties of these polymers were measured. When considering the results, it is obvious that irradiation acts on each polymer differently but, always when the optimal dose was found, the mechanical properties increased by up to 36%. The changes of micro-mechanical and thermo-mechanical properties were confirmed by structural measurement when the change of the micro-hardness and modulus corresponded to the crystalline phase change as determined by X-ray and gel content.
Fluorinated Polymers as Smart Materials for Advanced Biomedical Applications
Authors: Cardoso Vanessa , Correia Daniela , Ribeiro Clarisse , Fernandes Margarida , Lanceros-Méndez Senentxu
Published: February 2018

Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.
Crystallization Kinetics of Polyamide 12 during Selective Laser Sintering
Authors: Zhao Meng , Wudy Katrin , Drummer Dietmar
Published: February 2018

Selective laser sintering (SLS) of thermoplastic materials is an additive manufacturing process that overcomes the boundary between prototype construction and functional components. This technique also meets the requirements of traditional and established production processes. Crystallization behavior is one of the most critical properties during the cooling process and needs to be fully understood. Due to the huge influence of crystallization on the mechanical and thermal properties, it is important to investigate this process more closely. A commercial SLS polyamide (PA12) powder was measured with differential scanning calorimetry (DSC) to model a wider temperature range. To model isothermal crystallization between 160 and 168 °C, the Avrami model was used to determine the degree of crystallization. For non-isothermal crystallization between 0.2 and 20 K/min, different models were compared including the Ozawa, Jeziory, and Nakamura equations.
Nurses’ Understanding of Spirituality and the Spirituality of Older People with Dementia in the Continuing Care Setting
Authors: Keenan Paul , Kirwan Majella
Published: February 2018

This research paper was presented at the Third International Spirituality in Healthcare Conference 2017—‘Creating Space for Spirituality in Healthcare’ at Trinity College Dublin, The University of Dublin. 22 June 2017. The number of older people living with dementia in Ireland is rising. Dementia is prevalent among those residing in the continuing care setting. Nurses have a professional obligation to provide person centred, holistic care, to which spiritual care is a core element, yet often do not. As there are no guidelines in Ireland for spiritual care provision it is open to personal interpretation and application. This study was the first in Ireland to explore how spiritual care is understood by nurses in the context of older people living with dementia in a public, rural, continuing care setting. A qualitative descriptive design was utilized. Following purposive sampling, eight semi structured interviews were conducted in a rural Irish community hospital among registered nurses caring for older people living with dementia. A conceptual framework developed from the findings of a literature review, as well as this research study’s aim and objectives framed the interview schedule and data analysis. Data analysis utilized Newell and Burnard (2011) Thematic Content Analysis. Ethical approval was granted by the Health Service Executive (HSE) and the University of Dublin, Trinity College Dublin (TCD). Six key themes emerged from the study—1. Understandings of Spirituality, 2. Assessing spiritual need, 3. Providing spiritual care, 4. The impact of spirituality on quality of life, 5. Barriers to spiritual care and how these are addressed, and finally 6. The needs of staff. This paper presents and discusses the findings of the first theme ‘Understandings of Spirituality’ and its two sub-themes, 1. ‘The nurse’s own understanding of spirituality’ and 2. ‘The nurses’ understanding of spirituality and older people living with dementia.’ It is evident from the findings that there exists a variety of responses with regards to the nurses’ own understanding of the concept spirituality and spirituality for older people living with dementia. Participants placed emphasis on person-centred approaches to understanding and providing for the needs of care recipients’ in this area of care. Most participants acknowledged the positive impact of spiritual care on quality of life for older people living with dementia. Indications for practice suggest the need to develop suitable evidence based professional, person-centred frameworks, guidelines and educational standards for nurses which better equip them to understand spirituality and how this area of need can be properly assessed in partnership with the recipient of nursing practice in the continuing care setting to ensure comprehensive holistic, person-centred practice.
Water Quality Drivers in 11 Gulf of Mexico Estuaries
Authors: McCarthy Matthew , Otis Daniel , Méndez-Lázaro Pablo , Muller-Karger Frank
Published: February 2018

Coastal water-quality is both a primary driver and also a consequence of coastal ecosystem health. Turbidity, a measure of dissolved and particulate water-quality matter, is a proxy for water quality, and varies on daily to interannual periods. Turbidity is influenced by a variety of factors, including algal particles, colored dissolved organic matter, and suspended sediments. Identifying which factors drive trends and extreme events in turbidity in an estuary helps environmental managers and decision makers plan for and mitigate against water-quality issues. Efforts to do so on large spatial scales have been hampered due to limitations of turbidity data, including coarse and irregular temporal resolution and poor spatial coverage. We addressed these issues by deriving a proxy for turbidity using ocean color satellite products for 11 Gulf of Mexico estuaries from 2000 to 2014 on weekly, monthly, seasonal, and annual time-steps. Drivers were identified using Akaike’s Information Criterion and multiple regressions to model turbidity against precipitation, wind speed, U and V wind vectors, river discharge, water level, and El Nino Southern Oscillation and North Atlantic Oscillation climate indices. Turbidity variability was best explained by wind speed across estuaries for both time-series and extreme turbidity events, although more dynamic patterns were found between estuaries over various time steps.
Radiometric Correction of Close-Range Spectral Image Blocks Captured Using an Unmanned Aerial Vehicle with a Radiometric Block Adjustment
Authors: Honkavaara Eija , Khoramshahi Ehsan
Published: February 2018

Unmanned airborne vehicles (UAV) equipped with novel, miniaturized, 2D frame format hyper- and multispectral cameras make it possible to conduct remote sensing measurements cost-efficiently, with greater accuracy and detail. In the mapping process, the area of interest is covered by multiple, overlapping, small-format 2D images, which provide redundant information about the object. Radiometric correction of spectral image data is important for eliminating any external disturbance from the captured data. Corrections should include sensor, atmosphere and view/illumination geometry (bidirectional reflectance distribution function—BRDF) related disturbances. An additional complication is that UAV remote sensing campaigns are often carried out under difficult conditions, with varying illumination conditions and cloudiness. We have developed a global optimization approach for the radiometric correction of UAV image blocks, a radiometric block adjustment. The objective of this study was to implement and assess a combined adjustment approach, including comprehensive consideration of weighting of various observations. An empirical study was carried out using imagery captured using a hyperspectral 2D frame format camera of winter wheat crops. The dataset included four separate flights captured during a 2.5 h time period under sunny weather conditions. As outputs, we calculated orthophoto mosaics using the most nadir images and sampled multiple-view hyperspectral spectra for vegetation sample points utilizing multiple images in the dataset. The method provided an automated tool for radiometric correction, compensating for efficiently radiometric disturbances in the images. The global homogeneity factor improved from 12–16% to 4–6% with the corrections, and a reduction in disturbances could be observed in the spectra of the object points sampled from multiple overlapping images. Residuals in the grey and white reflectance panels were less than 5% of the reflectance for most of the spectral bands.
Impacts of Leaf Age on Canopy Spectral Signature Variation in Evergreen Chinese Fir Forests
Authors: Wu Qiaoli , Song Conghe , Song Jinling , Wang Jindi , Chen Shaoyuan , Yu Bo
Published: February 2018

Significant gaps exist in our knowledge of the impact of leaf aging on canopy signal variability, which limits our understanding of vegetation status based on remotely sensed data. To understand the effects of leaf aging at the leaf and canopy scales, a combination of field, remote-sensing and physical modeling techniques was adopted to assess the canopy spectral signals of evergreen Cunninghamia forests. We observed an approximately 10% increase in Near-Infrared (NIR) reflectance for new leaves and a 35% increase in NIR transmittance for mature leaves from May to October. When variations in leaf optical properties (LOPs) of only mature leaves, or both new and mature leaves were considered, the Geometric Optical and Radiative Transfer (GORT) model-simulated canopy reflectance trajectory was more consistent with Landsat observations (R2 increased from 0.37 to 0.82~0.89 for NIR reflectance, and from 0.35 to 0.67~0.88 for EVI2, with a small RMSE (0.01 to 0.02)). This study highlights the importance of leaf age on leaf spectral signatures, and provides evidence of age-dependent LOPs that have important impacts on canopy reflectance in the NIR band and EVI2, which are used to monitor canopy dynamics and productivity, with important implications for RS and forest ecosystem ecology.
Estimating Barley Biomass with Crop Surface Models from Oblique RGB Imagery
Authors: Brocks Sebastian , Bareth Georg
Published: February 2018

Non-destructive monitoring of crop development is of key interest for agronomy and crop breeding. Crop Surface Models (CSMs) representing the absolute height of the plant canopy are a tool for this. In this study, fresh and dry barley biomass per plot are estimated from CSM-derived plot-wise plant heights. The CSMs are generated in a semi-automated manner using Structure-from-Motion (SfM)/Multi-View-Stereo (MVS) software from oblique stereo RGB images. The images were acquired automatedly from consumer grade smart cameras mounted at an elevated position on a lifting hoist. Fresh and dry biomass were measured destructively at four dates each in 2014 and 2015. We used exponential and simple linear regression based on different calibration/validation splits. Coefficients of determination R 2 between 0.55 and 0.79 and root mean square errors (RMSE) between 97 and 234 g/m2 are reached for the validation of predicted vs. observed dry biomass, while Willmott’s refined index of model performance d r ranges between 0.59 and 0.77. For fresh biomass, R 2 values between 0.34 and 0.61 are reached, with root mean square errors (RMSEs) between 312 and 785 g/m2 and d r between 0.39 and 0.66. We therefore established the possibility of using this novel low-cost system to estimate barley dry biomass over time.
Effect of Crack on Durability of RC Material under the Chloride Aggressive Environment
Authors: Cheng Yongchun , Zhang Yuwei , Tan Guojin , Jiao Yubo
Published: February 2018

Exposed to aggressive environments, the rebar in reinforced concrete (RC) bridges will be corroded gradually. Durability of RC material mostly depends on the rebar corrosion behavior. In this research, influences of crack on rebar corrosion were investigated. Firstly, RC specimens with different crack number, width and spacing were prepared and the rebar corrosion was conducted through an accelerated chloride penetration method. Then, corrosion current densities of rebar were calculated from electrochemical test methods including liner polarization (LP), Tafel potentiodynamic polarization (TPP) and electrochemical impedance spectroscopy (EIS) measurements. Finally, the discussion was presented about a more reasonable electrochemical testing method for rebar corrosion in RC material. Besides, the significant influence factor among crack width, number and spacing was evaluated based on both One-way analysis of variance (One-way ANOVA) and Turkey’s honest significant difference (Turkey’s HSD) test. The results revealed that a more reasonable way to obtain corrosion current densities of rebar is combining EIS measurement with TPP measurement. Crack number shows the most significant effect on corrosion behavior of rebar, while crack spacing possesses the least one.
Resilience with Mixed Agricultural and Urban Land Uses in Tokyo, Japan
Authors: Sioen Giles , Terada Toru , Sekiyama Makiko , Yokohari Makoto
Published: February 2018

Urban agriculture can enhance the resilience of neighborhoods by providing fresh food in times of natural disasters; however, there is little empirical evidence to support this. Therefore, this study proposes a methodology to identify patterns of agricultural production in urban areas by quantifying self-sufficiency rates in vegetable weight and key nutrients. A spatial grid cell analysis using a geographic information system (GIS) identifies the current and potential self-sufficiency of each land use pattern in Tokyo. In a total of 1479 grid cells, the dominant land use and locations of 49,263 agricultural plots led to the categorization of six distinguishable land use patterns. The results showed that Tokyo has a fruit and vegetable self-sufficiency of 4.27% and a potential of 11.73%. The nutritional self-sufficiency of selected nutrients was the highest in vitamin K (6.54%), followed by vitamin C (3.84%) and vitamin A (1.92%). Peri-urban areas showed the highest resilience in relation to aggregated risks and population density because of the mixture in agricultural and urban land uses.
Impacts of Land-Use and Climate Change on Ecosystem Service in Eastern Tibetan Plateau, China
Authors: Tang Zhonglin , Sun Geng , Zhang Nannan , He Jing , Wu Ning
Published: February 2018

Past years have witnessed the transformation of land use at a high frequency and a warmer and drier climate in the Eastern Tibetan Plateau region. To fully understand the spatial-temporal variation of ecosystem services against the changing global backdrop and to provide scientific ecosystem management measures for decision-making, a study was conducted to investigate the major ecosystem services: water yield, soil conservation and crop production from 1990 to 2015 in the Eastern Tibetan Plateau region. Three scenarios—climate change only, land use change only and both land use and climate change—were included in this study to analyze the response of ES to the above-mentioned global changes. The results show that (1) the total quantity of ES reduced in all the three scenarios, the annual ES change was scenarioII < scenarioIII < scenarioI and the periodical characteristics are present in this region; (2) the ES change in spatial distribution varied with different climate change patterns and land use transfer directions; (3) the ES composition of each ecosystem varied with different driving scenarios and different responses of the forest and wetland on climate change and land use changes were observed. Moreover, the trade-off under land use change and climate change respectively was observed in this study. Based on the results, we recommend that the local government take this trade-off and climate change into account when making decisions, continue with desertification control and improve the quality of grassland as well as forests—these efforts should enable us to achieve sustainable development of human beings and the natural ecosystem.
PhcrTx2, a New Crab-Paralyzing Peptide Toxin from the Sea Anemone Phymanthus crucifer
Authors: Rodríguez Armando , Garateix Anoland , Salceda Emilio , Peigneur Steve , Zaharenko André , Pons Tirso , Santos Yúlica , Arreguín Roberto , Ständker Ludger , Forssmann Wolf-Georg , Tytgat Jan , Vega Rosario , Soto Enrique
Published: February 2018

Sea anemones produce proteinaceous toxins for predation and defense, including peptide toxins that act on a large variety of ion channels of pharmacological and biomedical interest. Phymanthus crucifer is commonly found in the Caribbean Sea; however, the chemical structure and biological activity of its toxins remain unknown, with the exception of PhcrTx1, an acid-sensing ion channel (ASIC) inhibitor. Therefore, in the present work, we focused on the isolation and characterization of new P. crucifer toxins by chromatographic fractionation, followed by a toxicity screening on crabs, an evaluation of ion channels, and sequence analysis. Five groups of toxic chromatographic fractions were found, and a new paralyzing toxin was purified and named PhcrTx2. The toxin inhibited glutamate-gated currents in snail neurons (maximum inhibition of 35%, IC50 4.7 µM), and displayed little or no influence on voltage-sensitive sodium/potassium channels in snail and rat dorsal root ganglion (DRG) neurons, nor on a variety of cloned voltage-gated ion channels. The toxin sequence was fully elucidated by Edman degradation. PhcrTx2 is a new β-defensin-fold peptide that shares a sequence similarity to type 3 potassium channels toxins. However, its low activity on the evaluated ion channels suggests that its molecular target remains unknown. PhcrTx2 is the first known paralyzing toxin in the family Phymanthidae.
Spatial Heterogeneity of Sustainable Transportation Offer Values: A Comparative Analysis of Nantes Urban and Periurban/Rural Areas (France)
Authors: Bulteau Julie , Feuillet Thierry , Le Boennec Rémy
Published: February 2018

Innovative solutions have been implemented to promote sustainable mobility in urban areas. In the Nantes area (northwestern part of France), alternatives to single-occupant car use have increased in the past few years. In the urban area, there is an efficient public transport supply, including tramways and a “busway” (Bus Rapid Transit), as well as bike-sharing services. In periurban and rural areas, there are carpool areas, regional buses and the new “tram-train” lines. In this article, we focus on the impact on house prices of these “sustainable” transportation infrastructures and policies, in order to evaluate their values. The implicit price of these sustainable transport offers was estimated through hedonic price functions describing the Nantes urban and periurban/rural housing markets. Spatial regression models (SAR, SEM, SDM and GWR) were carried out to capture the effect of both spatial autocorrelation and spatial heterogeneity. The results show patterns of spatial heterogeneity of transportation offer implicit prices at two scales: (i) between urban and periurban/rural areas, as well as (ii) within each territory. In the urban area, the distance to such offers was significantly associated with house prices. These associations varied by type of transportation system (positive for tramway and railway stations and negative for bike-sharing stations). In periurban and rural areas, having a carpool area in a 1500-m buffer around the home was negatively associated with house prices, while having a regional bus station in a 500-m buffer was non-significant. Distance to the nearest railway station was negatively associated with house prices. These findings provide research avenues to help public policy-makers promote sustainable mobility and pave the way for more locally targeted interventions.
Application of EMI and FDR Sensors to Assess the Fraction of Transpirable Soil Water over an Olive Grove
Authors: Rallo Giovanni , Provenzano Giuseppe , Castellini Mirko , Sirera Àngela
Published: February 2018

Accurate soil water status measurements across spatial and temporal scales are still a challenging task, specifically at intermediate spatial (0.1–10 ha) and temporal (minutes to days) scales. Consequently, a gap in knowledge limits our understanding of the reliability of the spatial measurements and its practical applicability in agricultural water management. This paper compares the cumulative EM38 (Geonics Ltd., Mississauga, ON, Canada) response collected by placing the sensor above ground with the corresponding soil water content obtained by integrating the values measured with an FDR (frequency domain reflectometry) sensor. In two field areas, characterized by different soil clay content, two Diviner 2000 access tubes (1.2 m) were installed and used to quantify the dimensionless fraction of transpirable soil water (FTSW). After the calibration, the work proposes the combined use of the FDR and electromagnetic induction (EMI) sensors to measure and map FTSW. A strong correlation (R2 = 0.86) between FTSW and EM38 bulk electrical conductivity was found. As a result, field changes of FTSW are due to the variability of soil water content and soil texture. As with the data acquired in the field, more structured patterns occurred after a wetting event, indicating the presence of subsurface flow or root water uptake paths. After assessing the relationship between the soil and crop water status, the FTSW domain includes a critical value, estimated around 0.38, below which a strong reduction of relative transpiration can be recognized.
Continuously Tracking the Annual Changes of the Hengsha and Changxing Islands at the Yangtze River Estuary from 1987 to 2016 Using Landsat Imagery
Authors: Xu Nan , Jia Dongzhen , Ding Lei , Wu Yan
Published: February 2018

The evolution of estuarine islands is potentially controlled by sediment discharge, tidal currents, sea level rise, and intensive human activities. An understanding of the spatial and temporal changes of estuarine islands is needed for environmental change monitoring and assessment in estuarine and coastal areas. Such information can also help us better understand how estuarine islands respond to sea level rise in the context of global warming. The temporal changes of two estuarine islands in Shanghai near the Yangtze River Estuary were obtained using Landsat TM (Thematic Mapper) and ETM+ (Enhanced Thematic Mapper) images from 1987 to 2016 on an annual scale. First, a composite image was generated by using the multi-temporal Landsat images for each year. Then, a modified normalized difference water index (MNDWI) was applied to the annual estuarine island maps using a threshold segmentation method. Finally, we obtained the temporal changes of the estuarine islands in Shanghai during the period 1987–2016. The results suggest that (1) Landsat TM/ETM+ images can be used for estuarine island mapping and change detection; (2) the two estuarine islands have expanded significantly during the past three decades; (3) human activities are the main driving factor that caused the expansion of the estuarine islands; and (4) the sea level can also partly explain the change in the estuarine islands. This study demonstrates that Landsat data are useful for determining the annual variations in the land area of two estuarine islands in Shanghai during the past 30 years. In the future, other factors and their contributions to estuarine island changes should be further investigated.
Comparison of Precipitation and Streamflow Correcting for Ensemble Streamflow Forecasts
Authors: Li Yilu , Jiang Yunzhong , Lei Xiaohui , Tian Fuqiang , Duan Hao , Lu Hui
Published: February 2018

Meteorological centers constantly make efforts to provide more skillful seasonal climate forecast, which has the potential to improve streamflow forecasts. A common approach is to bias-correct the general circulation model (GCM) forecasts prior to generating the streamflow forecasts. Less attention has been paid to the issue of bias-corrected streamflow forecasts that were generated by GCM forecasts. This study compares the effect of bias-corrected GCM forecasts and bias-corrected streamflow outputs on the improvement of streamflow forecast efficiency. Based on the Upper Hanjiang River Basin (UHRB), the authors compare three forecasting scenarios: original forecasts, bias-corrected precipitation forecasts and bias-corrected streamflow forecasts. We apply the quantile mapping method to bias-correct precipitation forecasts and the linear scaling method to bias-correct the original streamflow forecasts. A semi-distributed hydrological model, namely the Tsinghua Representative Elementary Watershed (THREW) model, is employed to transform precipitation into streamflow. The effects of bias-corrected precipitation and bias-corrected streamflow are assessed in terms of accuracy, reliability, sharpness and overall performance. The results show that both bias-corrected precipitation and bias-corrected streamflow can considerably increase the overall forecast skill in comparison to the original streamflow forecasts. Bias-corrected precipitation contributes mainly to improving the forecast reliability and sharpness, while bias-corrected streamflow is successful in increasing the forecast accuracy and overall performance of the ensemble forecasts.
Urban Floods and Climate Change Adaptation: The Potential of Public Space Design When Accommodating Natural Processes
Authors: Silva Maria Matos , Costa João Pedro
Published: February 2018

Urban public space is extraordinarily adaptable under a pattern of relatively stable changes. However, when facing unprecedented and potentially extreme climatic changes, public spaces may not have the same adaptation capacity. In this context, planned adaptation gains strength against “business as usual”. While public spaces are among the most vulnerable areas to climatic hazards, they entail relevant characteristics for adaptation efforts. As such, public space design can lead to effective adaptation undertakings, explicitly influencing urban design practices as we know them. Amongst its different intrinsic roles and benefits, such as being a civic common gathering place of social and economic exchanges, public space may have found an enhanced protagonism under the climate change adaptation perspective. In light of the conducted empirical analysis, which gathered existing examples of public spaces with flood adaptation purposes, specific public space potentialities for the application of flood adaptation measures are here identified and characterized. Overall, this research questions the specific social potentiality of public space adaptation in the processes of vulnerability tackling, namely considering the need of alternatives in current flood management practices. Through literature review and case study analysis, it is here argued that: people and communities can be perceived as more than susceptible targets and rather be professed as active agents in the process of managing urban vulnerability; that climate change literacy, through the design of a public space, may endorse an increased common need for action and the pursuit of suitable solutions; and that local know-how and locally-driven design can be considered as a service with added value for adaptation endeavors.
Puerarin Inhibits Proliferation and Induces Apoptosis by Upregulation of miR-16 in Bladder Cancer Cell Line T24
Authors: Liu Xiaoyun , Li Shuguang , Li Yanyan , Cheng Bo , Tan Bo , Wang Gang
Published: February 2018

Bladder cancer (BC) is a common disease of the urinary system. Puerarin is a flavonoid extracted from Pueraria lobata. However, the role of puerarin in BC remains unclear. Hence, this study aimed to investigate the effect of puerarin on BC cells. Cell viability, proliferation,
and apoptosis were measured by CCK-8, BrdU assay, and flow cytometry analysis, respectively. The expressions of miR-16, apoptosis-related factors, and the main factors of the NF-κB pathway were analyzed by qRT-PCR and Western blot. In this study, we found that cell viability and proliferation
were significantly reduced, cell apoptosis was enhanced, and the mRNA level of miR-16 was upregulated in puerarin-treated T24 cells. Further, silencing of miR-16 inhibited the decrease in cell viability and the increase in apoptosis. The expression of main factors involved in the NF-κB
signaling pathway was downregulated in the puerarin group, while miR-16 silencing alleviated these downregulations. More importantly, puerarin deactivated the NF-κB signaling pathway via upregulation of miR-16. Also, miR-16 downregulated COX-2 expression via deactivation of the NF-κB
signaling pathway. This study demonstrated that puerarin could inhibit cell proliferation, promote cell apoptosis, and deactivate NF-κB signaling pathway via upregulation of miR-16 in T24 cells.
MicroRNA-139-3p Suppresses Tumor Growth and Metastasis in Hepatocellular Carcinoma by Repressing ANXA2R
Authors: Zou Zeng Cheng , Dai Min , Huang Zeng Yin , Lu Yi , Xie He Ping , Li Yi Fang , Li Yue , Tan Ying , Wang Feng Lin
Published: February 2018

The direct roles of miR-139-3p on hepatocellular carcinoma (HCC) cell growth and metastasis remain poorly understood. We attempted to demonstrate the regulatory role of miR-139-3p in HCC progression and its underlying mechanisms. Here we showed that miR-139-3p expression was significantly
reduced in the HCC tissues compared to paratumor tissues. Exogenous overexpression of miR-139-3p inhibited the migration and invasion of HCC cells, whereas downregulation of miR-139-3p was able to induce HCC HepG2 and SNU-449 cell migration and invasion. In addition, miR-139-3p inhibited HCC
growth and lung metastasis in an in vivo mouse model, which is mainly regulated by annexin A2 receptor (ANXA2R). Finally, we identified that the expression of miR-139-3p was inversely correlated with ANXA2R expression in human HCC tissue. All these results demonstrated that miR-139-3p inhibited
the metastasis process in HCC by downregulating ANXA2R expression.
The Effect of Selective c-MET Inhibitor on Hepatocellular Carcinoma in the MET-Active, β-Catenin-Mutated Mouse Model
Authors: Zhan Na , Michael Adeola Adebayo , Wu Kaiyuan , Zeng Gang , Bell Aaron , Tao Junyan , Monga Satdarshan P.
Published: February 2018

Simultaneous mutations in CTNNB1 and activation of c-MET occur in 9%‐12.5% of patients with hepatocellular carcinoma (HCC). Coexpression of c-MET-V5 and mutant β-catenin-Myc in mouse liver by sleeping beauty transposon/transposase and hydrodynamic tail vein injection (SB-HTVI)
led to the development of HCC with 70% molecular identity to the clinical subset. Using this model, we investigated the effect of EMD1214063, a highly selective c-MET inhibitor. Five weeks after SB-HTVI when tumors were established, EMD1214063 (10 mg/kg) was administered by gastric gavage
as a single agent on 5-day-on/3-day-off schedule, compared to vehicle only control. Mice were harvested at 8 or 11 weeks posttreatment. Decreased p-MET, p-AKT, p-STAT3, and p-ERK proved in vivo efficacy of EMD1214063. We observed lower Ki-67, PCNA, V5-tag, and cyclin D1 after EMD1214063 treatment
only at 8 weeks. Overall, no significant differences were observed in tumor burden between the groups, although EMD1214063 marginally but significantly improved overall survival by 1.5‐2 weeks. Tumors remained α-fetoprotein+, did not show any differences in inflammation,
and lacked fibrosis in either group. In conclusion, c-MET inhibition alone had a minor effect on Met-β-catenin HCC at the early stages of HCC development. Thus, a single therapy with the c-MET inhibitor will be insufficient for sustained response in Met-β-catenin HCC requiring assessment of additional combinations.
Formation of H2O+ and H3O+ Cations in Reactions of OH+ and H2O+ with H2: Experimental Studies of the Reaction Rate Coefficients from T = 15 to 300 K
Authors: Tran Thuy Dung , Rednyk Serhiy , Kovalenko Artem , Roučka Štěpán , Dohnal Petr , Plašil Radek , Gerlich Dieter , Glosík Juraj
Published: February 2018

and

cations play a significant role in the chemistry of the cold interstellar medium and hence their hydrogen abstraction reactions with

have to be included in ion chemical models. The reactions lead directly or indirectly to

ions that subsequently recombine with electrons and dissociate into H atoms and

. The experiments described in this paper provide rate coefficients (

and

) for the reactions of

and

with

over a wide temperature range (from 15 to 300 K). A cryogenic 22-pole RF ion trap instrument was employed for this purpose. It was found that

increases from

at 17 K to

at 263 K while

is nearly constant, varying from

at 17 K to

at 218 K.
Angular Momentum Evolution of Stellar Disks at High Redshifts
Authors: Okamura Taku , Shimasaku Kazuhiro , Kawamata Ryota
Published: February 2018

The stellar disk size of a galaxy depends on the ratio of the disk stellar mass to the halo mass, m
⋆ ≡ M
⋆/M
dh, and the fraction of the dark halo angular momentum transferred to the stellar disk, j
⋆ ≡ J
⋆/J
dh. Since m
⋆ and j
⋆ are determined by many star formation–related processes, measuring j
⋆ and m
⋆ at various redshifts is essential to understanding the formation history of disk galaxies. We use the 3D-HST GOODS-S, COSMOS, and AEGIS imaging data and photo-z catalog to examine j
⋆ and m
⋆ for star-forming galaxies at z ∼ 2–4, when disks are actively forming. We find that the j
⋆/m
⋆ ratio is ≃0.77 ± 0.06 for all three redshifts over the entire mass range examined, 8 × 1010 < M
dh/h
−1
M
⊙ < 2 × 1012, with a possible (<30%) decrease with mass. This high ratio is close to those of local disk galaxies, descendants of our galaxies in terms of M
dh growth, implying a nearly constant j
⋆/m
⋆ over the past 12 Gyr. These results are remarkable because mechanisms controlling angular momentum transfer to disks such as inflows and feedback depend on both cosmic time and halo mass, and, indeed, theoretical studies tend to predict j
⋆/m
⋆ changing with redshift and mass. It is found that some of the recent theoretical galaxy formation simulations predict a smaller j
⋆/m
⋆ than our values. We also find that a significant fraction of our galaxies appears to be unstable against bar formation.
A Disk Origin for the Monoceros Ring and A13 Stellar Overdensities
Authors: Sheffield Allyson A. , Price-Whelan Adrian M. , Tzanidakis Anastasios , Johnston Kathryn V. , Laporte Chervin F. P. , Sesar Branimir
Published: February 2018

The Monoceros Ring (also known as the Galactic Anticenter Stellar Structure) and A13 are stellar overdensities at estimated heliocentric distances of d ∼ 11 kpc and 15 kpc observed at low Galactic latitudes toward the anticenter of our Galaxy. While these overdensities were initially thought to be remnants of a tidally disrupted satellite galaxy, an alternate scenario is that they are composed of stars from the Milky Way (MW) disk kicked out to their current location due to interactions between a satellite galaxy and the disk. To test this scenario, we study the stellar populations of the Monoceros Ring and A13 by measuring the number of RR Lyrae and M giant stars associated with these overdensities. We obtain low-resolution spectroscopy for RR Lyrae stars in the two structures and measure radial velocities to compare with previously measured velocities for M giant stars in the regions of the Monoceros Ring and A13, to assess the fraction of RR Lyrae to M giant stars (f
RR:MG) in A13 and Mon/GASS. We perform velocity modeling on 153 RR Lyrae stars (116 in the Monoceros Ring and 37 in A13) and find that both structures have very low f
RR:MG. The results support a scenario in which stars in A13 and Mon/GASS formed in the MW disk. We discuss a possible association between Mon/GASS, A13, and the Triangulum-Andromeda overdensity based on their similar velocity distributions and f
RR:MG.
Role of Core-collapse Supernovae in Explaining Solar System Abundances of p Nuclides
Authors: Travaglio C. , Rauscher T. , Heger A. , Pignatari M. , West C.
Published: February 2018

The production of the heavy stable proton-rich isotopes between 74Se and 196Hg—the p nuclides—is due to the contribution from different nucleosynthesis processes, activated in different types of stars. Whereas these processes have been subject to various studies, their relative contributions to Galactic chemical evolution (GCE) are still a matter of debate. Here we investigate for the first time the nucleosynthesis of p nuclides in GCE by including metallicity and progenitor mass-dependent yields of core-collapse supernovae (ccSNe) into a chemical evolution model. We used a grid of metallicities and progenitor masses from two different sets of stellar yields and followed the contribution of ccSNe to the Galactic abundances as a function of time. In combination with previous studies on p-nucleus production in thermonuclear supernovae (SNIa), and using the same GCE description, this allows us to compare the respective roles of SNeIa and ccSNe in the production of p-nuclei in the Galaxy. The γ process in ccSN is very efficient for a wide range of progenitor masses (13 M
⊙–25 M
⊙) at solar metallicity. Since it is a secondary process with its efficiency depending on the initial abundance of heavy elements, its contribution is strongly reduced below solar metallicity. This makes it challenging to explain the inventory of the p nuclides in the solar system by the contribution from ccSNe alone. In particular, we find that ccSNe contribute less than 10% of the solar p nuclide abundances, with only a few exceptions. Due to the uncertain contribution from other nucleosynthesis sites in ccSNe, such as neutrino winds or α-rich freeze out, we conclude that the light p-nuclides 74Se, 78Kr, 84Sr, and 92Mo may either still be completely or only partially produced in ccSNe. The γ-process accounts for up to twice the relative solar abundances for 74Se in one set of stellar models and 196Hg in the other set. The solar abundance of the heaviest p nucleus 196Hg is reproduced within uncertainties in one set of our models due to photodisintegration of the Pb isotopes 208,207,206Pb. For all other p nuclides, abundances as low as 2% of the solar level were obtained.
Imaging and Variability Studies of CTA 102 during the 2016 January γ-ray Flare
Authors: Li Xiaofeng , Mohan P. , An T. , Hong Xiaoyu , Cheng Xiaopeng , Yang Jun , Zhang Yingkang , Zhang Zhongli , Zhao Wei
Published: February 2018

The γ-ray-bright blazar CTA 102 is studied using imaging (new 15 GHz and archival 43 GHz Very Long Baseline Array, VLBA data) and time variable optical flux density, polarization degree, and electric vector position angle (EVPA) spanning between 2015 June 1 and 2016 October 1, covering a prominent γ-ray flare during 2016 January. The pc-scale jet indicates expansion with oscillatory features up to 17 mas. Component proper motions are in the range 0.04–0.33 mas yr−1 with acceleration up to 1.2 mas followed by a slowing down beyond 1.5 mas. A jet bulk Lorentz factor ≥17.5, position angle of 128.°3, inclination angle ≤6.°6 and intrinsic half opening angle ≤1.°8 are derived from the VLBA data. These inferences are employed in a helical jet model to infer long-term variability in flux density, polarization degree, EVPA, and a rotation of the Stokes Q and U parameters. A core distance of r
core,43 GHz = 22.9 pc, and a magnetic field strength at 1 pc and the core location of 1.57 G and 0.07 G, respectively, are inferred using the core-shift method. The study is useful in the context of estimating jet parameters and in offering clues to distinguish mechanisms responsible for variability over different timescales.
Dynamical Formation of Close Binaries during the Pre-main-sequence Phase
Authors: Moe Maxwell , Kratter Kaitlin M.
Published: February 2018

Solar-type binaries with short orbital periods (

 days; a ≲ 0.1 au) cannot form directly via fragmentation of molecular clouds or protostellar disks, yet their component masses are highly correlated, suggesting interaction during the pre-main-sequence (pre-MS) phase. Moreover, the close binary fraction of pre-MS stars is consistent with that of their MS counterparts in the field (

). Thus, we can infer that some migration mechanism operates during the early pre-MS phase (τ ≲ 5 Myr) that reshapes the primordial separation distribution. We test the feasibility of this hypothesis by carrying out a population synthesis calculation which accounts for two formation channels: Kozai–Lidov (KL) oscillations and dynamical instability in triple systems. Our models incorporate (1) more realistic initial conditions compared to previous studies, (2) octupole-level effects in the secular evolution, (3) tidal energy dissipation via weak-friction equilibrium tides at small eccentricities and via non-radial dynamical oscillations at large eccentricities, and (4) the larger tidal radius of a pre-MS primary. Given a 15% triple-star fraction, we simulate a close binary fraction from KL oscillations alone of

after τ = 5 Myr, which increases to

by τ = 5 Gyr. Dynamical ejections and disruptions of unstable coplanar triples in the disk produce solitary binaries with slightly longer periods P ≈ 10–100 days. The remaining ≈60% of close binaries with outer tertiaries, particularly those in compact coplanar configurations with log

(days) ≈ 2–5 (

 au), can be explained only with substantial extra energy dissipation due to interactions with primordial gas.
Hidden Universality in the Merger Rate Distribution in the Primordial Black Hole Scenario
Authors: Kocsis Bence , Suyama Teruaki , Tanaka Takahiro , Yokoyama Shuichiro
Published: February 2018

It has been proposed that primordial black holes (PBHs) form binaries in the radiation dominated era. Once formed, some fraction of them may merge within the age of the universe by gravitational radiation reaction. We investigate the merger rate of the PBH binaries when the PBHs have a distribution of masses around

, which is a generalization of the previous studies where the PBHs are assumed to have the same mass. After deriving a formula for the merger time probability distribution in the PBH mass plane, we evaluate it under two different approximations. We identify a quantity constructed from the mass distribution of the merger rate density per unit cosmic time and comoving volume

,

, which universally satisfies 0.97 ≲ α ≲ 1.05 for all binary masses independently of the PBH mass function. This result suggests that the measurement of this quantity is useful for testing the PBH scenario.
Rapid Evolution of the Gaseous Exoplanetary Debris around the White Dwarf Star HE 1349–2305
Authors: Dennihy E. , Clemens J. C. , Dunlap B. H. , Fanale S. M. , Fuchs J. T. , Hermes J. J.
Published: February 2018

Observations of heavy metal pollution in white dwarf stars indicate that metal-rich planetesimals are frequently scattered into star-grazing orbits, tidally disrupted, and accreted onto the white dwarf surface, offering direct insight into the dynamical evolution of post-main-sequence exoplanetary systems. Emission lines from the gaseous debris in the accretion disks of some of these systems show variations on timescales of decades, and have been interpreted as the general relativistic precession of a recently formed, elliptical disk. Here we present a comprehensive spectroscopic monitoring campaign of the calcium infrared triplet emission in one system, HE 1349–2305, which shows morphological emission profile variations suggestive of a precessing, asymmetric intensity pattern. The emission profiles are shown to vary on a timescale of one to two years, which is an order of magnitude shorter than what has been observed in other similar systems. We demonstrate that this timescale is likely incompatible with general relativistic precession, and consider alternative explanations for the rapid evolution, including the propagation of density waves within the gaseous debris. We conclude with recommendations for follow-up observations, and discuss how the rapid evolution of the gaseous debris in HE 1349–2305 could be leveraged to test theories of exoplanetary debris disk evolution around white dwarf stars.
Stellar Bar Evolution in the Absence of Dark Matter Halo
Authors: Roshan Mahmood
Published: February 2018

We study the stellar bar growth in high-resolution numerical galaxy models with and without dark matter halos. In all models, the galactic disk is exponential, and the halos are rigid or live Plummer spheres. More specifically, when there is no dark matter halo, we modify the gravitational force between point particles. To do so, we use the weak field limit of an alternative theory of dark matter known as MOG in the literature. The galaxy model in MOG has the same initial conditions as galaxy models with a dark matter halo. On the other hand, the initial random velocities and Toomre’s local stability parameter are the same for all of the models. We show that the evolution and growth of the bar in MOG is substantially different from the standard cases including dark matter halo. More importantly, we find that the bar growth rate and its final magnitude are smaller in MOG. On the other hand, the maximum value of the bar in MOG is smaller than that in the Newtonian models. It is shown that although the live dark matter halo may support bar instability, MOG has stabilizing effects. Furthermore, we show that MOG supports fast pattern speeds, and unlike in the dark matter halo models, the pattern speed does not decrease with time. These differences, combined with the relevant observations, may help to distinguish between dark matter and modified gravity in galactic scales.