bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of an Extreme Storm Event on River Corridor Bank Erosion and Phosphorus Mobilization in a Mountainous Watershed in the Northeastern United States
Authors: Ross Donald S. , Wemple Beverley C. , Willson Lindsay J. , Balling Courtney M. , Underwood Kristen L. , Hamshaw Scott D. 
Published: December 2018

AbstractMovement of sediment, and associated phosphorus, from stream banks to freshwater lakes is predicted to increase with greater frequency of extreme precipitation events. This higher phosphorus load may accelerate harmful algal blooms in affected water bodies, such as Lake Champlain in Vermont, New York, and Québec. In the Mad River, a subwatershed in central Vermont's Lake Champlain Basin, extreme flooding from Tropical Storm Irene in 2011 caused extensive erosion. We measured stream channel change along the main stem between 2008 and 2011 by digitizing available prestorm and poststorm aerial imagery. Soils were sampled post Irene at six active stream erosion sites, using an experimental design to measure differences in soil texture and phosphorus both with depth (90 cm) and distance from the stream. In addition to total phosphorus (TP), we determined bioavailable (soil test) phosphorus (STP) and the degree of phosphorus saturation (DPS). The six sites represented a 0.87‐km length of stream bank that contributed an estimated 17.6 × 103 Mg of sediment and 15.8 Mg of TP, roughly the same as average annual watershed export estimates. At four sites, the STP and DPS were low and suggested little potential for short‐term phosphorus release. At two agricultural sites where the lateral extent of erosion was high, imagery showed a clear loss of well‐established riparian buffer. Present‐day near‐stream soils were elevated in STP and DPS. An increase in these extreme events will clearly increase sediment loads. There will also be increasing concentration of sediment phosphorus if stream banks continue to erode into actively managed agricultural fields.
Effects of Cyanobacterial Soil Crusts on Surface Roughness and Splash Erosion
Authors: Bullard Joanna E. , Ockelford Annie , Strong Craig , Aubault Helene 
Published: December 2018

AbstractSoil surface roughness (SSR) modifies interactions and feedback processes between terrestrial and atmospheric systems driven by both the abiotic and biotic components of soils. This paper compares SSR response to a low‐intensity multiday rainfall event for soils with and without early successional stage cyanobacteria‐dominated biological soil crusts (CBCs). A rainfall simulator was used to apply 2, 5, and 2 mm of rain separated by a 24‐hr period over 3 days at an intensity of 60 mm/hr. Changes in SSR were quantified using geostatistically derived indicators calculated from semivariogram analysis of high‐resolution laser scans. The CBCs were stronger and splash erosion substantially less than from the physical soil crusts. Prior to rainfall treatment, soils with CBCs had greater SSR than those without. The rainfall treatments caused the physical crusted soils to increase SSR and spatial patterning due to the translocation of particles, soil loss, and the development of raindrop impact craters. Rainfall caused swelling of cyanobacterial filaments but only a slight increase in SSR, and raindrop impact cratering and splash loss were low on the soils with CBCs. There is no relationship between random roughness and splash erosion, but an increase in splash loss was associated with an increase in topographic roughness and small‐scale spatial patterning. A comparison of this study with other research indicates that for rainfall events up to 100 mm, the effectiveness of CBCs in reducing soil loss is >80% regardless of the rainfall amount and intensity, which highlights their importance for landscape stabilization.
The selective pressures on the microbial community in a metal-contaminated aquifer
Authors: Carlson Hans K , Price Morgan N , Callaghan Mark , Aaring Alex , Chakraborty Romy , Liu Hualan , Kuehl Jennifer V , Arkin Adam P , Deutschbauer Adam M 
Published: December 2018

Abstract
In many environments, toxic compounds restrict which microorganisms persist. However, in complex mixtures of inhibitory compounds, it is challenging to determine which specific compounds cause changes in abundance and prevent some microorganisms from growing. We focused on a contaminated aquifer in Oak Ridge, Tennessee, USA that has large gradients of pH and widely varying concentrations of uranium, nitrate, and many other inorganic ions. In the most contaminated wells, the microbial community is enriched in the Rhodanobacter genus. Rhodanobacter abundance is positively correlated with low pH and high concentrations of uranium and 13 other ions and we sought to determine which of these ions are selective pressures that favor the growth of Rhodanobacter over other taxa. Of these ions, low pH and high UO22+, Mn2+, Al3+, Cd2+, Zn2+, Co2+, and Ni2+ are both (a) selectively inhibitory of a Pseudomonas isolate from an uncontaminated well vs. a Rhodanobacter isolate from a contaminated well, and (b) reach toxic concentrations (for the Pseudomonas isolate) in the Rhodanobacter-dominated wells. We used mixtures of ions to simulate the groundwater conditions in the most contaminated wells and verified that few isolates aside from Rhodanobacter can tolerate these eight ions. These results clarify which ions are likely causal factors that impact the microbial community at this field site and are not merely correlated with taxonomic shifts. Furthermore, our general high-throughput approach can be applied to other environments, isolates, and conditions to systematically help identify selective pressures on microbial communities.
Ultrastructural pathology of oligodendrocytes adjacent to microglia in prefrontal white matter in schizophrenia
Authors: Uranova Natalya A. , Vikhreva Olga V. , Rakhmanova Valentina I. , Orlovskaya Diana D. 
Published: December 2018

AbstractMicroglial activation has been proposed to be involved in the pathophysiology of schizophrenia (SCZ). We hypothesized that dystrophic alterations of oligodendrocytes previously reported in the prefrontal white matter in SCZ might be associated with microglial activation in the acute state of SCZ. White matter of the prefrontal cortex (BA10) was studied in post-mortem brain tissue from 21 SCZ cases and 20 normal controls. The SCZ group included 12 subjects with predominantly positive symptoms and 9 subjects with predominantly negative symptoms. Electron microscopy was applied to estimate cell density, size, volume fraction (Vv) and the number (N) of organelles in oligodendrocytes adjacent to microglia and in oligodendrocytes adjacent to myelin, neurons and capillaries and not adjacent to microglia. Cell density of oligodendrocytes was not changed in the SCZ group as compared to controls. Vv and N of mitochondria were significantly decreased, while Vv of vacuoles of endoplasmic reticulum and lipofuscin granules were significantly increased in oligodendrocytes adjacent to either microglia or myelin in the SCZ group and in patients displaying predominantly positive symptoms as compared to the control group. There were no significant differences between oligodendrocytes adjacent to microglia and to myelin. Vv and N of lipofuscin were also increased in peri-capillary oligodendrocytes. There was no effect of clinical subgroups on the parameters of peri-capillary and peri-neuronal oligodendrocytes. Though many ameboid and dystrophic microglia adjacent to oligodendrocytes were found in the SCZ samples, we provide no quantitative evidence that oligodendrocyte dystrophy is associated with microglial activation in white matter in SCZ.
Baculovirus as an efficient vector for gene delivery into mosquitoes
Authors: Naik Nenavath Gopal , Lo Yu-Wen , Wu Tzong-Yuan , Lin Chang-Chi , Kuo Szu-Cheng , Chao Yu-Chan 
Published: December 2018

AbstractEfficient gene delivery technologies play an essential role in the gene functional analyses that are necessary for basic and applied researches. Mosquitoes are ubiquitous insects, responsible for transmitting many deadly arboviruses causing millions of human deaths every year. The lack of efficient and flexible gene delivery strategies in mosquitoes are among the major hurdles for the study of mosquito biology and mosquito-pathogen interactions. We found thatAutographa californicamultiple nucleopolyhedrovirus (AcMNPV), the type baculovirus species, can efficiently transduce mosquito cells without viral propagation, allowing high level gene expression upon inducement by suitable promoters without obvious negative effects on cell propagation and viability. AcMNPV transduces into several mosquito cell types, efficiently than in commonly used mammalian cell lines and classical plasmid DNA transfection approaches. We demonstrated the application of this system by expressing influenza virus neuraminidase (NA) into mosquito hosts. Moreover, AcMNPV can transduce both larvae and adults of essentially all blood-sucking mosquito genera, resulting in bright fluorescence in insect bodies with little or no tissue barriers. Our experiments establish baculovirus as a convenient and powerful gene delivery vectorin vitroandin vivothat will greatly benefit research into mosquito gene regulation, development and the study of mosquito-borne viruses.
Quantum Renormalization of Spin Squeezing in Spin Chains
Authors: Balazadeh Leila , Najarbashi Ghader , Tavana Ali 
Published: December 2018

AbstractBy employing quantum renormalization group (QRG) method, we investigate quantum phase transitions (QPT) in the Ising transverse field (ITF) model and in the XXZ Heisenberg model, with and without Dzyaloshinskii Moriya (DM) interaction, on a periodic chain of N lattice sites. We adopt a new approach called spin squeezing as an indicator of QPT. Spin squeezing, through analytical expression of a spin squeezing parameter, is calculated after each step of QRG. As the scale of the system becomes larger, (after many QRG steps), the ground state (GS) spin squeezing parameters show an abrupt change at a quantum critical point (QCP). Moreover, in all of the studied models, the first derivative of the spin squeezing parameter with respect to the control parameter is discontinuous, which is a signature of QPT. The spin squeezing parameters develop their saturated values after enough QRG iterations. The divergence exponent of the first derivative of the spin squeezing parameter in the near vicinity of the QCP is associated with the critical exponent of the correlation length.
microRNA-29b mediates fibrotic induction of human xylosyltransferase-I in human dermal fibroblasts via the Sp1 pathway
Authors: Riedel Lara , Fischer Bastian , Ly Thanh-Diep , Hendig Doris , Kuhn Joachim , Knabbe Cornelius , Faust Isabel 
Published: December 2018

AbstractDiminished microRNA-29b levels have recently been revealed to provoke increased expression and accumulation of extracellular matrix molecules, such as collagens in fibrotic remodeling. Subsequently, the aim of this study was to find out whether microRNA-29b might also regulate human xylosyltransferase (XT)-I expression. XT-I has been characterized previously as a fibrosis biomarker catalyzing the key step of proteoglycan biosynthesis. While we demonstrate that XYLT1 is neither a target of microRNA-29b identified in silico nor a direct 3′ untranslated region binding partner of microRNA-29b, transfection of normal human dermal fibroblasts with microRNA-29b inhibitor strongly increased XYLT1 mRNA expression and XT activity. Combined results of the target prediction analysis and additional transfection experiments pointed out that microRNA-29b exerts indirect influence on XT-I by targeting the transcription factor specificity protein 1 (Sp1). We could confirm our hypothesis due to the decrease in XYLT1 promoter activity after Sp1 binding site mutation and the approval of occupancy of these binding sites by Sp1 in vitro. Taken together, a hitherto unidentified pathway of XT-I regulation via microRNA-29b/Sp1 was determined in this study. Our observations will facilitate the understanding of complex molecular fibrotic pathways and provide new opportunities to investigate microRNA-based antifibrotic tools.
The crystal structure of a tetrahydrofolate-bound dihydrofolate reductase reveals the origin of slow product release
Authors: Cao Hongnan , Gao Mu , Zhou Hongyi , Skolnick Jeffrey 
Published: December 2018

AbstractDihydrofolate reductase (DHFR) catalyzes the stereospecific reduction of 7,8-dihydrofolate (FH2) to (6s)-5,6,7,8-tetrahydrofolate (FH4) via hydride transfer from NADPH. The consensus Escherichia coli DHFR mechanism involves conformational changes between closed and occluded states occurring during the rate-limiting product release step. Although the Protein Data Bank (PDB) contains over 250 DHFR structures, the FH4 complex structure responsible for rate-limiting product release is unknown. We report to our knowledge the first crystal structure of an E. coli. DHFR:FH4 complex at 1.03 Å resolution showing distinct stabilizing interactions absent in FH2 or related (6R)-5,10-dideaza-FH4 complexes. We discover the time course of decay of the co-purified endogenous FH4 during crystal growth, with conversion from FH4 to FH2 occurring in 2–3 days. We also determine another occluded complex structure of E. coli DHFR with a slow-onset nanomolar inhibitor that contrasts with the methotrexate complex, suggesting a plausible strategy for designing DHFR antibiotics by targeting FH4 product conformations.
GPR120 protects lipotoxicity-induced pancreatic β-cell dysfunction through regulation of PDX1 expression and inhibition of islet inflammation
Authors: Wang Yi , Xie Ting , Zhang Dan , Leung Po Sing 
Published: December 2018

Abstract
G-protein coupled receptor 120 (GPR120) has been shown to act as an omega-3 unsaturated fatty acid sensor and is involved in insulin secretion. However, the underlying mechanism in pancreatic β cells remains unclear. To explore the potential link between GPR120 and β-cell function, its agonists docosahexaenoic acid (DHA) and GSK137647A were used in palmitic acid (PA)-induced pancreatic β-cell dysfunction, coupled with GPR120 knockdown (KD) in MIN6 cells and GPR120 knockout (KO) mice to identify the underlying signaling pathways. In vitro and ex vivo treatments of MIN6 cells and islets isolated from wild-type (WT) mice with DHA and GSK137647A restored pancreatic duodenal homeobox-1 (PDX1) expression levels and β-cell function via inhibiting PA-induced elevation of proinflammatory chemokines and activation of nuclear factor κB, c-Jun amino (N)-terminal kinases1/2 and p38MAPK signaling pathways. On the contrary, these GPR120 agonism-mediated protective effects were abolished in GPR120 KD cells and islets isolated from GPR120 KO mice. Furthermore, GPR120 KO mice displayed glucose intolerance and insulin resistance relative to WT littermates, and β-cell functional related genes were decreased while inflammation was exacerbated in islets with increased macrophages in pancreas from GPR120 KO mice. DHA and GSK137647A supplementation ameliorated glucose tolerance and insulin sensitivity, as well as improved Pdx1 expression and islet inflammation in diet-induced obese WT mice, but not in GPR120 KO mice. These findings indicate that GPR120 activation is protective against lipotoxicity-induced pancreatic β-cell dysfunction, via the mediation of PDX1 expression and inhibition of islet inflammation, and that GPR120 activation may serve as a preventative and therapeutic target for obesity and diabetes.
Compact microstrip balanced bandpass filter with adjustable transmission zeros
Authors: Xiao Jian‐Kang , Su Xiao‐Bao , Wang Hui‐Xia , Ma Jian‐Guo 
Published: December 2018

A compact microstrip balanced bandpass filter (BPF) with a pair of adjustable transmission zeros (TZs) and a common mode suppression of over 20 dB in a frequency range of >2.42f0 by using the mixed electromagnetic coupling technology has been developed. The filter TZs in differential‐mode are attributed to the mixed electromagnetic coupling, and can be adjusted by the electric/magnetic coupling individually. The filter bandwidth can also be controlled by the electromagnetic coupling. The proposed balanced BPF has been fabricated and measured, and the prediction has been demonstrated.
Adapted near‐state PWM for dual two‐level inverters in order to reduce common‐mode voltage and switching losses
Authors: Aghazadeh Amir , Khodabakhshi‐Javinani Naser , Nafisi Hamed , Davari Masoud , Pouresmaeil Edris 
Published: December 2018

In this paper, a near‐state pulse‐width modulation (NSPWM) algorithm is proposed and implemented on dual‐two‐level voltage‐source inverters (D2L‐VSIs) in order to reduce the common‐mode voltage (CMV), the inverter switching losses, the current total harmonic distortion, and the side effects of bearing currents ‐‐compared with space vector modulation (SVM) and PWM7. To gain these goals, two conventional two‐level inverters of the D2L‐VSI are controlled, separately, with specific switching sequences and an adjusted phase difference between the carriers of two inverters. For evaluating and comparing these PWM techniques mathematically, both CMV root mean square generated and switching losses of the D2L‐VSI are formulated as a function of the power factor of the D2L‐VSI, which is driven by the methods detailed in this study. Eventually, theories and analysis, as well as simulations and experimental results ‐‐which are generated by MATLAB/Simulink environment and a 300 W scaled‐down D2LVSI prototype, respectively ‐‐authenticate the superiority of the proposed NSPWM over both SVM and PWM7.
Emission of Joule heating events in simulations of the solar corona
Authors: Kanella Charalambos , Gudiksen Boris V. 
Published: December 2018

Context. Nanoscale events in cooperation with steady heating from a slow heating mechanism, such as slow-burning current-sheets, could be able to heat the corona; however, their observational traces are hard to detect via current instrumentation. After we locate heating events in magnetohydrodynamic (MHD) simulations and synthesise observational data, we extract observational signatures of small-scale events.
Aims. Our mission is threefold. The first goal is to observe the manifestation of small-scale events via three observational tools: intensity maps of three extreme ultraviolet (EUV) filters in the Atmospheric Imaging Assembly (AIA) instrument with resolution better than that in AIA images, emission measure (EM) analysis, and time-lag maps. The second goal is to identify the reason why we cannot quantify the energy release from observed events. The third goal is to study the differences between the radiation from isolated heating events and that from the whole corona.
Methods. We employed a three-dimensional magnetohydrodynamic (3D-MHD) simulation using the Bifrost code. We simulated the atmosphere of a network embedded in the quiet Sun (QS), and we identified 3D heating events in the corona in several time-steps. Then we synthesised the three observational tools for two cases. First, we considered information from the total column mass in the corona, and then we considered only regions that exhibit heating events.
Results. We report on the differences between the two regions of investigation, which also consist of the evidence to justify why observers cannot identify small-scale heating events in observations. We found that the combination of multiple heating events at different cooling phases along the line of sight gives the impression of thin elongated threads of events. For this reason, the EM as a function of temperature has a multi-thermal distribution. Both the radiation and the emission measure of the isolated heating events have values at least ten times lower than the signal calculated from the total corona. We also found that heating events move together with diffuse emission from the slow heating mechanism, and for this reason we cannot differentiate between the two. In addition, we find that the frequency of heating events and their intensity affect the EM distribution as a function of temperature. We also find that the filter’s intensity, EM, and time-lag maps of heating events are different to those incorporating information from the total column mass of the corona. However, the two regions have, on average, comparable values, which are slightly smaller than the analytical cooling timescales calculated for an optically thin and radiation-dominated atmosphere.
A-PHOT: a new, versatile code for precision aperture photometry
Authors: Merlin E. , Pilo S. , Fontana A. , Castellano M. , Paris D. , Roscani V. , Santini P. , Torelli M. 
Published: December 2018

Aims. We present A-PHOT, a new publicly available code for performing aperture photometry on astronomical images, that is particularly well suited for multi-band extragalactic surveys.
Methods.A-PHOT estimates the fluxes emitted by astronomical objects within a chosen set of circular or elliptical apertures. Unlike other widely used codes, it runs on predefined lists of detected sources, allowing for repeated measurements on the same list of objects on different images. This can be very useful when forced photometric measurement on a given position is needed. A-PHOT can also estimate morphological parameters and a local background flux, and compute on-the-fly individual optimized elliptical apertures, in which the signal-to-noise ratio is maximized.
Results. We check the performance of A-PHOT on both synthetic and real test datasets: we explore a simulated case of a space-based high-resolution imaging dataset, investigating the input parameter space to optimize the accuracy of the performance, and we exploit the CANDELS GOODS-South data to compare the A-PHOT measurements with those from the survey legacy catalogs, finding good agreement overall.
Conclusions.A-PHOT proves to a useful and versatile tool for quickly extracting robust and accurate photometric measurements and basic morphological information of galaxies and stars, with the advantage of allowing for various measurements of fluxes at any chosen position without the need of a full detection run, and for determining the basic morphological features of the sources.