bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrological Storage Length Scales Represented by Remote Sensing Estimates of Soil Moisture and Precipitation
Authors: Akbar Ruzbeh , Short Gianotti Daniel , McColl Kaighin A. , Haghighi Erfan , Salvucci Guido D. , Entekhabi Dara 
Published: February 2018

AbstractThe soil water content profile is often well correlated with the soil moisture state near the surface. They share mutual information such that analysis of surface‐only soil moisture is, at times and in conjunction with precipitation information, reflective of deeper soil fluxes and dynamics. This study examines the characteristic length scale, or effective depth Δz, of a simple active hydrological control volume. The volume is described only by precipitation inputs and soil water dynamics evident in surface‐only soil moisture observations. To proceed, first an observation‐based technique is presented to estimate the soil moisture loss function based on analysis of soil moisture dry‐downs and its successive negative increments. Then, the length scale Δz is obtained via an optimization process wherein the root‐mean‐squared (RMS) differences between surface soil moisture observations and its predictions based on water balance are minimized. The process is entirely observation‐driven. The surface soil moisture estimates are obtained from the NASA Soil Moisture Active Passive (SMAP) mission and precipitation from the gauge‐corrected Climate Prediction Center daily global precipitation product. The length scale Δz exhibits a clear east‐west gradient across the contiguous United States (CONUS), such that large Δz depths (>200 mm) are estimated in wetter regions with larger mean precipitation. The median Δz across CONUS is 135 mm. The spatial variance of Δz is predominantly explained and influenced by precipitation characteristics. Soil properties, especially texture in the form of sand fraction, as well as the mean soil moisture state have a lesser influence on the length scale.
A Reduced‐Order Successive Linear Estimator for Geostatistical Inversion and its Application in Hydraulic Tomography
Authors: Zha Yuanyuan , Yeh Tian‐Chyi J. , Illman Walter A. , Zeng Wenzhi , Zhang Yonggen , Sun Fangqiang , Shi Liangsheng 
Published: February 2018

AbstractHydraulic tomography (HT) is a recently developed technology for characterizing high‐resolution, site‐specific heterogeneity using hydraulic data (nd) from a series of cross‐hole pumping tests. To properly account for the subsurface heterogeneity and to flexibly incorporate additional information, geostatistical inverse models, which permit a large number of spatially correlated unknowns (ny), are frequently used to interpret the collected data. However, the memory storage requirements for the covariance of the unknowns (ny × ny) in these models are prodigious for large‐scale 3‐D problems. Moreover, the sensitivity evaluation is often computationally intensive using traditional difference method (ny forward runs). Although employment of the adjoint method can reduce the cost to nd forward runs, the adjoint model requires intrusive coding effort. In order to resolve these issues, this paper presents a Reduced‐Order Successive Linear Estimator (ROSLE) for analyzing HT data. This new estimator approximates the covariance of the unknowns using Karhunen‐Loeve Expansion (KLE) truncated to nkl order, and it calculates the directional sensitivities (in the directions of nkl eigenvectors) to form the covariance and cross‐covariance used in the Successive Linear Estimator (SLE). In addition, the covariance of unknowns is updated every iteration by updating the eigenvalues and eigenfunctions. The computational advantages of the proposed algorithm are demonstrated through numerical experiments and a 3‐D transient HT analysis of data from a highly heterogeneous field site.
Effect of Water Surface Salinity on Evaporation: The Case of a Diluted Buoyant Plume Over the Dead Sea
Authors: Mor Z. , Assouline S. , Tanny J. , Lensky I. M. , Lensky N. G. 
Published: February 2018

AbstractEvaporation from water bodies strongly depends on surface water salinity. Spatial variation of surface salinity of saline water bodies commonly occurs across diluted buoyant plumes fed by freshwater inflows. Although mainly studied at the pan evaporation scale, the effect of surface water salinity on evaporation has not yet been investigated by means of direct measurement at the scale of natural water bodies. The Dead Sea, a large hypersaline lake, is fed by onshore freshwater springs that form local diluted buoyant plumes, offering a unique opportunity to explore this effect. Surface heat fluxes, micrometeorological variables, and water temperature and salinity profiles were measured simultaneously and directly over the salty lake and over a region of diluted buoyant plume. Relatively close meteorological conditions prevailed in the two regions; however, surface water salinity was significantly different. Evaporation rate from the diluted plume was occasionally 3 times larger than that of the main salty lake. In the open lake, where salinity was uniform with depth, increased wind speed resulted in increased evaporation rate, as expected. However, in the buoyant plume where diluted brine floats over the hypersaline brine, wind speed above a threshold value (∼4 m s−1) caused a sharp decrease in evaporation probably due to mixing of the stratified plume and a consequent increase in the surface water salinity.
The Role of Frozen Soil in Groundwater Discharge Predictions for Warming Alpine Watersheds
Authors: Evans Sarah G. , Ge Shemin , Voss Clifford I. , Molotch Noah P. 
Published: February 2018

AbstractClimate warming may alter the quantity and timing of groundwater discharge to streams in high alpine watersheds due to changes in the timing of the duration of seasonal freezing in the subsurface and snowmelt recharge. It is imperative to understand the effects of seasonal freezing and recharge on groundwater discharge to streams in warming alpine watersheds as streamflow originating from these watersheds is a critical water resource for downstream users. This study evaluates how climate warming may alter groundwater discharge due to changes in seasonally frozen ground and snowmelt using a 2‐D coupled flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative snowmelt‐dominated watershed in the Rocky Mountains of central Colorado, USA, with snowmelt time series reconstructed from a 12 year data set of hydrometeorological records and satellite‐derived snow covered area. Model analyses indicate that the duration of seasonal freezing in the subsurface controls groundwater discharge to streams, while snowmelt timing controls groundwater discharge to hillslope faces. Climate warming causes changes to subsurface ice content and duration, rerouting groundwater flow paths but not altering the total magnitude of future groundwater discharge outside of the bounds of hydrologic parameter uncertainties. These findings suggest that frozen soil routines play an important role for predicting the future location of groundwater discharge in watersheds underlain by seasonally frozen ground.
Effect of secondary electron generation on dose enhancement in Lipiodol with and without a flattening filter
Authors: Kawahara Daisuke , Ozawa Shuichi , Saito Akito , Kimura Tomoki , Suzuki Tatsuhiko , Tsuneda Masato , Tanaka Sodai , Nakashima Takeo , Ohno Yoshimi , Murakami Yuji , Nagata Yasushi 
Published: February 2018

AbstractPurposeLipiodol, which was used in transcatheter arterial chemoembolization before liver stereotactic body radiation therapy (SBRT), remains in SBRT. Previous we reported the dose enhancement in Lipiodol using 10 MV (10×) FFF beam. In this study, we compared the dose enhancement in Lipiodol and evaluated the probability of electron generation (PEG) for the dose enhancement using flattening filter (FF) and flattening filter free (FFF) beams.MethodsFF and FFF for 6 MV (6×) and 10× beams were delivered by TrueBeam. The dose enhancement factor (DEF), energy spectrum, and PEG was calculated using Monte Carlo (MC) code BEAMnrc and heavy ion transport code system (PHITS).ResultsDEFs for FF and FFF 6× beams were 7.0% and 17.0% at the center of Lipiodol (depth, 6.5 cm). DEFs for FF and FFF 10× beams were 8.2% and 10.5% at the center of Lipiodol. Spectral analysis revealed that the FFF beams contained more low‐energy (0–0.3 MeV) electrons than the FF beams, and the FF beams contained more high‐energy (>0.3 MeV) electrons than the FFF beams in Lipiodol. The difference between FFF and FF beam DEFs was larger for 6× than for 10×. This occurred because the 10× beams contained more high‐energy electrons. The PEGs for photoelectric absorption and Compton scattering for the FFF beams were higher than those for the FF beams. The PEG for the photoelectric absorption was higher than that for Compton scattering.ConclusionsFFF beam contained more low‐energy photons and it contributed to the dose enhancement. Energy spectra and PEGs are useful for analyzing the mechanisms of dose enhancement.
Graphene and Carbon‐Nanotube Nanohybrids Covalently Functionalized by Porphyrins and Phthalocyanines for Optoelectronic Properties
Authors: Wang Aijian , Ye Jun , Humphrey Mark G. , Zhang Chi 
Published: February 2018

AbstractIn recent years, there has been a rapid growth in studies of the optoelectronic properties of graphene, carbon nanotubes (CNTs), and their derivatives. The chemical functionalization of graphene and CNTs is a key requirement for the development of this field, but it remains a significant challenge. The focus here is on recent advances in constructing nanohybrids of graphene or CNTs covalently linked to porphyrins or phthalocyanines, as well as their application in nonlinear optics. Following a summary of the syntheses of nanohybrids constructed from graphene or CNTs and porphyrins or phthalocyanines, explicit intraconjugate electronic interactions between photoexcited porphyrins/phthalocyanines and graphene/CNTs are introduced classified by energy transfer, electron transfer, and charge transfer, and their optoelectronic applications are also highlighted. The major current challenges for the development of covalently linked nanohybrids of porphyrins or phthalocyanines and carbon nanostructures are also presented.
N‐Heterocyclic Carbene‐Catalyzed Double Michael Addition: Stereoselective Synthesis of Spirofluorenes and Multisubstituted Indanes
Authors: Xing Fen , Feng Ze‐Nan , Wang Ying , Du Guang‐Fen , Gu Cheng‐Zhi , Dai Bin , He Lin 
Published: February 2018

AbstractThe strong Brønsted basic character of N‐heterocyclic carbenes (NHCs) has been used to promote the cascade double Michael addition between fluorenes and dienones. Under catalyst loadings of 1–5 mol% of NHC, fluorene reacts with divinyl ketones (DVKs) to afford anti‐spirofluorene compounds in high yields. However, when benzenedi(enones) were employed as Michael acceptors in the presence of 10 mol% of NHC, fluorene undergoes a different inter‐ and intramolecular cascade double Michael addition, providing multi‐substituted indanes in high yields with excellent diastereoselectivity.magnified image
A Tunable Route to Prepare α,β‐Unsaturated Esters and α,β‐Unsaturated‐γ‐Keto Esters through Copper‐Catalyzed Coupling of Alkenyl Boronic Acids with Phosphorus Ylides
Authors: Bi Hong‐Yan , Liu Feng‐Ping , Liang Cui , Su Gui‐Fa , Mo Dong‐Liang 
Published: February 2018

AbstractA tunable strategy to prepare α,β‐unsaturated esters and α,β‐unsaturated‐γ‐keto esters in good to excellent yields was developed through copper‐catalyzed oxidative coupling of phosphorus ylides with alkenyl boronic acids under mild conditions. The reaction without water afforded α,β‐unsaturated esters, ketones, and amides while α,β‐unsaturated‐γ‐keto esters, 1,4‐α,β‐unsaturated diketones and α,β‐unsaturated‐γ‐keto amides were obtained when using 5.0 equiv. of water. H2O18 labeling experiments showed that water played an important role in the formation of α,β‐unsaturated‐γ‐keto esters. A plausible formation mechanism for α,β‐unsaturated esters and α,β‐unsaturated‐γ‐keto esters was proposed based on mechanistic studies. Phosphonium salts could also be used directly as coupling partners instead of phosphorus ylides. The reaction exhibited a broad substrate scope, good functional group tolerance, good regioselectivity, and diverse coupling products.magnified image
New Insight on Tuning Electrical Transport Properties via Chalcogen Doping in n‐type Mg3Sb2‐Based Thermoelectric Materials
Authors: Zhang Jiawei , Song Lirong , Borup Kasper Andersen , Jørgensen Mads Ry Vogel , Iversen Bo Brummerstedt 
Published: February 2018

Abstractn‐type Mg3Sb1.5Bi0.5 has recently been discovered to be a promising thermoelectric material, yet the effective n‐type dopants are mainly limited to the chalcogens. This may be attributed to the limited chemical insight into the effects from different n‐type dopants. By comparing the effects of different chalcogen dopants Q (Q = S, Se, and Te) on thermoelectric properties, it is found that the chalcogen dopants Q become more efficient with decreasing electronegativity difference between Q and Mg, which is mainly due to the increasing carrier concentration and mobility. Using density functional theory calculations, it is shown that the improving carrier concentration originates from the increasing doping limit induced by the stabilizing extrinsic defect. Moreover, the increasing electron mobility with decreasing electronegativity difference between Q and Mg is attributed to the smaller effective mass resulting from the enhancing chemical bond covalency, which is supported by the decreasing theoretical density of states. According to the above trends, a simple guiding principle based on electronegativity is proposed to shed new light on n‐type doping in Zintl antimonides.
Direct Measurement of Charge Regulation in Metalloprotein Electron Transfer
Authors: Zahler Collin T. , Zhou Hongyu , Abdolvahabi Alireza , Holden Rebecca L. , Rasouli Sanaz , Tao Peng , Shaw Bryan F. 
Published: February 2018

AbstractDetermining whether a protein regulates its net electrostatic charge during electron transfer (ET) will deepen our mechanistic understanding of how polypeptides tune rates and free energies of ET (e.g., by affecting reorganization energy, and/or redox potential). Charge regulation during ET has never been measured for proteins because few tools exist to measure the net charge of a folded protein in solution at different oxidation states. Herein, we used a niche analytical tool (protein charge ladders analyzed with capillary electrophoresis) to determine that the net charges of myoglobin, cytochrome c, and azurin change by 0.62±0.06, 1.19±0.02, and 0.51±0.04 units upon single ET. Computational analysis predicts that these fluctuations in charge arise from changes in the pKa values of multiple non‐coordinating residues (predominantly histidine) that involve between 0.42–0.90 eV. These results suggest that ionizable residues can tune the reactivity of redox centers by regulating the net charge of the entire protein–cofactor–solvent complex.
An Organic Mixed‐Valence Ligand for Multistate Redox‐Active Coordination Networks
Authors: Ha Joo Yeon , Koo Jin Young , Ohtsu Hiroyoshi , Yakiyama Yumi , Kim Kimoon , Hashizume Daisuke , Kawano Masaki 
Published: February 2018

AbstractThe multistate redox‐active/multi‐interactive ligand 5,5′,8,8′‐tetra(4‐pyridyl)‐2,2′‐(1,4‐phenylene)bis‐1H‐perimidine (H2TPP) was designed and synthesized. H2TPP undergoes four one‐electron oxidation steps, and was used for the preparation of a multistate redox‐active coordination network in a solid–liquid interface reaction using molten Cd2+ salts. The multiple redox states of H2TPP were confirmed spectroscopically by stepwise four‐electron oxidation. Spectroscopic analysis indicated that the mixed‐valence states of the ligand are class II on the UV/Vis/NIR timescale and borderline class II/class III on the ESR timescale.
Helicenophyrins: Expanded Carbaporphyrins Incorporating Aza[5]helicene and Heptacyclic S‐Shaped Aza[5]helicene Motifs
Authors: Szyszko Bartosz , Przewoźnik Monika , Białek Michał J. , Białońska Agata , Chmielewski Piotr J. , Cichos Jakub , Latos‐Grażyński Lechosław 
Published: February 2018

AbstractIncorporation of phenanthrene into a hexaphyrin(1.1.1.1.1.0) frame resulted in intramolecular ring fusion, thus giving rise to chiral helicenophyrins. These molecules contain helicene and porphyrin features by incorporating either an aza[5]helicene or heptacyclic S‐shaped aza[5]helicene.
Phosphorus‐containing silica gel‐coated ammonium polyphosphate: Preparation, characterization, and its effect on the flame retardancy of rigid polyurethane foam
Authors: Chen Yajun , Li Linshan , Xu Lifeng , Qian Lijun 
Published: February 2018

ABSTRACTA phosphorus‐containing silica gel was synthesized via a reaction between phenyl dichlorophosphate, poly(ether polyol), and γ‐aminopropyltriethoxysilane. Ammonium polyphosphate (APP) was modified by the synthesized phosphorus‐containing silica gel (MAPP) and then incorporated into the rigid polyurethane foam (PU). Results showed that APP had a smaller particle size, lower initial decomposition temperature, better heat resistance at high temperature, and better compatibility with PU matrix after the modification. The cone calorimeter test results showed that the incorporation of MAPP obviously reduced the values including peak of heat release rate, total heat release, average effective heat of combustion, and total smoke release, and increased the char yield of PU composite comparing with APP. The improved flame retardancy of PU/MAPP composite was attributed to the quenching effect of PO· and PO2· free radicals released by MAPP in the early stage and the improved thermal stability of phosphorus‐ and silicon‐containing char layer formed in the later stage. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46334.
Identification and expression profiles of novel odorant binding proteins and functional analysis of OBP99a in Bactrocera dorsalis
Authors: Zhang Jing , Luo Deye , Wu Peng , Li Haozhe , Zhang Hongyu , Zheng Weiwei 
Published: February 2018

AbstractOdorant‐binding proteins (OBPs) in insects are essential for mating and oviposition host selection. How these OBPs respond to different hosts at the mRNA level and their effects on behavior remain poorly characterized. The oriental fruit fly Bactrocera dorsalis is a highly invasive agricultural pest with an extremely broad host range and high fecundity. Based on our previously constructed B. dorsalis transcriptome, six OBPs that were differentially expressed during three different physiological adult stages were identified. A phylogenetic tree was constructed to illustrate the relationships of these six OBPs with OBP sequences from three other dipteran species (Drosophila melanogaster, Anopheles gambiae, and Ceratitis capitata). The spatiotemporal expression profiles of the six OBPs were analyzed using quantitative real‐time PCR. Our results revealed that OBP19c, OBP44a, OBP99a, and OBP99d were abundantly expressed from the prepupa stage to the adult stage, and most of the OBPs were mainly expressed in the head, wings, and antennae. The expression levels of these OBPs were upregulated when female flies were exposed to their preferred hosts. Silencing OBP99a resulted fewer eggs being laid compared with the control group when the females were exposed to their preferred host, that is, banana, whereas more eggs were laid when a non‐preferred host, that is, tomato, was used. Furthermore, silencing OBP99a led to sexually dimorphic mating behavior. dsOBP99a‐injected males dramatically reduced courtship, whereas enhanced courtship was observed in the treated females. These data indicate that OBPs may participate in different biological processes of B. dorsalis. Our study will provide insight into the molecular mechanism of chemoreception and help develop ecologically friendly pest‐control strategies.
Clickable Polyamine Derivatives as Chemical Probes for the Polyamine Transport System
Authors: Vanhoutte Roeland , Kahler Jan Pascal , Martin Shaun , van Veen Sarah , Verhelst Steven H. L. 
Published: February 2018

AbstractPolyamines are essential for cell growth and differentiation, but their trafficking by the polyamine transport system is not fully understood. Herein, the synthesis of several azido‐derivatized polyamines for easy conjugation by click chemistry is described. Attachment of a 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) dye gave fluorescent polyamine probes, which were tested in cell culture. The linear probe series showed superior cellular uptake compared with that of probes in which the dye was attached to a branch on one of the central amines. Interestingly, the linear probes accumulated rapidly in cancer cells (MCF‐7), but not in nontumorigenic cells (MCF‐10A). The fluorescent polyamine probes are therefore applicable to the study of polyamine trafficking, whereas the azido polyamines may be further utilized to transport cargo into cancer cells by exploiting the polyamine transport system.
Numerical Investigation on Granular Flow from a Wedge‐Shaped Feed Hopper Using the Discrete Element Method
Authors: Liu Yilun , Liu Siqi , Chen Hui , Zhao Xianqiong , Liu Chi , Wu Tianxiang , Su Jiahui 
Published: February 2018

AbstractThe discharge process of granular material from a wedge‐shaped feed hopper was numerically simulated using a 3D discrete element method. The effects of particle size, feed pipe, side and rear wedge angle on the discharge performance were investigated in terms of flow pattern, discharge rate, and stability. The results show that with larger particle size the granular flow pattern gradually transforms from mass flow to edge flow where the flow rate decreases and the discharging integrity and stability become worse. The presence of the feed pipe reduces the discharge rate and stability. The increase of the feed pipe diameter will diminish the discharge rate and enhance the discharge stability. Both the side and the rear wedge angle have a certain effect on the discharge performance. The effects of feed pipe, side and rear wedge angle on the discharge stability become more significant with larger particle size.
Extraction of Spruce Lignin with a Deep Eutectic Solvent in Dependence of the Particle Size
Authors: Schäfer Tobias , Eisenlauer Moritz , Teipel Ulrich 
Published: February 2018

AbstractInfolge der zunehmenden Nutzung nachwachsender Rohstoffe müssen neue Rohstoffströme erschlossen und die Prozessschritte bei deren Nutzung in ihrer Effizienz gesteigert werden. Lignin ist eine potenzielle Quelle für einkernige aromatische Verbindungen. In dieser Arbeit wird gezeigt, dass die eutektische Mischung aus Cholinchlorid und 3‐Phenylpropionsäure als interessantes Extraktionsmedium für Lignin dienen kann. Um die Ausbeute zu bestimmen, wurde Lignin mit Phloroglucin eingefärbt und mittels UV/Vis‐Spektroskopie quantifiziert. Die Ausbeute wurde in Abhängigkeit der Partikelgröße des unter optimalen Bedingungen zerkleinerten Fichtenholzes definierter Herkunft untersucht.