bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climate scientists need to set the record straight: There is a scientific consensus that human‐caused climate change is happening
Authors: Maibach Edward , Myers Teresa , Leiserowitz Anthony 
Published: April 2014

AbstractNearly all climate scientists are convinced that human‐caused climate change is occurring, yet half of Americans do not know or do not believe that a scientific consensus has been reached. That such a large proportion of Americans do not understand that there is a near‐unanimous scientific consensus about the basic facts of climate change matters, a lot. This essay briefly explains why, and what climate science societies and individual climate scientists can do to set the record straight.
Impact of HIWIND balloon measurements on thermospheric density models
Authors: Moe Kenneth , Wu Qian 
Published: April 2014

AbstractThe recent HIWIND (High‐Altitude Interferometer Wind Observations) balloon measurements have revealed persistent equatorward winds in the dayside thermosphere during geomagnetically quiet times. Although this result does not agree with some current thermospheric density models, it is consistent with an earlier thermospheric density model (M1975) which includes the energy input through the magnetospheric dayside cusps during geomagnetically quiet times. We show the thermospheric density distribution with and without the magnetospheric input to illustrate the effect of the density gradient on the winds at high latitudes. We review the early history of the development of our understanding of the energy input to the high‐latitude thermosphere. Future HIWIND measurements can add to our understanding and lead to improved models of thermospheric densities and winds.
Sill intrusion as a source mechanism of unrest at volcanic calderas
Authors: Macedonio G. , Giudicepietro F. , D'Auria L. , Martini M. 
Published: April 2014

AbstractThe interpretation of dynamic processes that occur in volcanic calderas is not simple. The ground deformations and the local seismicity, which in other volcanic contexts are usually regarded as precursors to eruption, in caldera environment in many cases are not followed by any eruption. We formulate a general hypothesis that can explain these behaviors. Our hypothesis is that the intrusion of a sill can be responsible for the dynamics observed during unrest at calderas. In order to investigate the reliability of this hypothesis, we developed a dynamic model of sill intrusion in a shallow volcanic environment. In our model, the sill, fed by a deeper magma reservoir, intrudes below a horizontal elastic plate, representing the overlying rocks, and expands with axisymmetric geometry. The model is based on the numerical solution of the equation for the elastic plate, coupled with a Navier‐Stokes equation for simulating the dynamics of the sill intrusion. We performed a number of simulations, with the objective of showing the main features of the model. In the experiments, when the feeding process stops, the vertical movement reverses its trend and the area of maximum uplift undergoes subsidence. Under certain conditions the subsidence can occur even during the intrusion of the sill. The stress field produced by the intrusion is mainly concentrated in a circular zone that follows the sill intrusion front. The features predicted by the model are consistent with many observations carried out on different calderas as reported in the scientific literature.
Methyl chloride in the upper troposphere observed by the CARIBIC passenger aircraft observatory: Large‐scale distributions and Asian summer monsoon outflow
Authors: Umezawa T. , Baker A. K. , Oram D. , Sauvage C. , O'Sullivan D. , Rauthe‐Schöch A. , Montzka S. A. , Zahn A. , Brenninkmeijer C. A. M. 
Published: April 2014

AbstractWe present spatial and temporal variations of methyl chloride (CH3Cl) in the upper troposphere (UT) observed mainly by the Civil Aircraft for Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC) passenger aircraft for the years 2005–2011. The CH3Cl mixing ratio in the UT over Europe was higher than that observed at a European surface baseline station throughout the year, indicative of a persistent positive vertical gradient at Northern Hemisphere midlatitudes. A series of flights over Africa and South Asia show that CH3Cl mixing ratios increase toward tropical latitudes, and the observed UT CH3Cl level over these two regions and the Atlantic was higher than that measured at remote surface sites. Strong emissions of CH3Cl in the tropics combined with meridional air transport through the UT may explain such vertical and latitudinal gradients. Comparisons with carbon monoxide (CO) data indicate that noncombustion sources in the tropics dominantly contribute to forming the latitudinal gradient of CH3Cl in the UT. We also observed elevated mixing ratios of CH3Cl and CO in air influenced by biomass burning in South America and Africa, and the enhancement ratios derived for CH3Cl to CO in those regions agree with previous observations. In contrast, correlations indicate a high CH3Cl to CO ratio of 2.9 ± 0.5 ppt ppb−1in the Asian summer monsoon anticyclone and domestic biofuel emissions in South Asia are inferred to be responsible. We estimated the CH3Cl emission in South Asia to be 134 ± 23 Gg Cl yr−1, which is higher than a previous estimate due to the higher CH3Cl to CO ratio observed in this study.
The robust dynamical contribution to precipitation extremes in idealized warming simulations across model resolutions
Authors: Lu Jian , Ruby Leung L. , Yang Qing , Chen Gang , Collins William D. , Li Fuyu , Jason Hou Z. , Feng Xuelei 
Published: April 2014

AbstractThe impact of the circulation shift under climate warming on the distribution of precipitation extremes and the associated sensitivity to model resolution are investigated using Community Atmosphere Model Version 3.0 in an aquaplanet configuration. The response of the probability density function of the precipitation to a uniform sea surface temperature warming can be interpreted as superimposition of a dynamically induced poleward shift and a thermodynamically induced upward shift toward higher intensities, which give rise to manyfold increase in the frequency of the most extreme categories of the precipitation events at the poleward side of the midlatitude storm track. Coarser resolutions underestimate not only the intensity of the precipitation extremes but also the dynamical contribution to the increase of precipitation extremes. Meanwhile, the thermodynamic contribution to the intensification of the precipitation extremes is substantially less than expected from the Clausius‐Clapeyron relation, implicative of significant change in the vertical structure of the precipitation processes.
Asymmetric Hydrogenation of Maleic Acid Diesters and Anhydrides
Authors: Bernasconi Maurizio , Müller Marc‐André , Pfaltz Andreas 
Published: April 2014

AbstractAsymmetric hydrogenation of maleic and fumaric acid derivatives with iridium catalysts based on N,P ligands provides an efficient route to chiral enantioenriched succinates. A new catalyst derived from a 2,6‐difluorophenyl‐substituted pyridine‐phosphinite ligand was developed and enables the conversion of a wide range of 2‐alkyl and 2‐arylmaleic acid diesters into the corresponding succinates in high enantiomeric purity. Mixtures of cis/trans substrates can be hydrogenated in an enantioconvergent fashion with high enantioselectivity, and further enhances the scope of this transformation. The products are valuable chiral building blocks with a structural motif found in many bioactive compounds, such as metalloproteinase inhibitors.
Boron Radical Cations from the Facile Oxidation of Electron‐Rich Diborenes
Authors: Bissinger Philipp , Braunschweig Holger , Damme Alexander , Kupfer Thomas , Krummenacher Ivo , Vargas Alfredo 
Published: April 2014

AbstractThe realization of a phosphine‐stabilized diborene, Et3P⋅(Mes)BB(Mes)⋅PEt3 (4), by KC8 reduction of Et3P⋅B2Mes2Br2 in benzene enabled the evaluation and comparison of its electronic structure to the previously described NHC‐stabilized diborene IMe⋅(Dur)BB(Dur)⋅IMe (1). Importantly, both species feature unusual electron‐rich boron centers. However, cyclic voltammetry, UV/Vis spectroscopy, and DFT calculations revealed a significant influence of the Lewis base on the reduction potential and absorption behavior of the BB double bond system. Thus, the stronger σ‐donor strength and larger electronegativity of the NHC ligand results in an energetically higher‐lying HOMO, making 1 a stronger neutral reductant as 4 (1: E1/2=−1.55 V; 4: −1.05 V), and a smaller HOMO–LUMO gap of 1 accompanied by a noticeable red‐shift of its lowest‐energy absorption band with respect to 4. Owing to the highly negative reduction potentials, 1 and 4 were easily oxidized to afford rare boron‐centered radical cations (5 and 6).
A review of fracturing fluid systems used for hydraulic fracturing of oil and gas wells
Authors: Barati Reza , Liang Jenn‐Tai 
Published: April 2014

ABSTRACTHydraulic fracturing has been used by the oil and gas industry as a way to boost hydrocarbon production since 1947. Recent advances in fracturing technologies, such as multistage fracturing in horizontal wells, are responsible for the latest hydrocarbon production boom in the US. Linear or crosslinked guars are the most commonly used fluids in traditional fracturing operations. The main functions of these fluids are to open/propagate the fractures and transport proppants into the fractures. Proppants are usually applied to form a thin layer between fracture faces to prop the fractures open at the end of the fracturing process. Chemical breakers are used to break the polymers at the end of the fracturing process so as to provide highly conductive fractures. Concerns over fracture conductivity damage by viscous fluids in ultra‐tight formations found in unconventional reservoirs prompted the industry to develop an alternative fracturing fluid called “slickwater”. It consists mainly of water with a very low concentration of linear polymer. The low concentration polymer serves primarily to reduce the friction loss along the flow lines. Proppant‐carrying capability of this type of fluids is still a subject of debate among industry experts. Constraints on local water availability and the potential for damage to formations have led the industry to develop other types of fracturing fluids such as viscoelastic surfactants and energized fluids. This article reviews both the traditional viscous fluids used in conventional hydraulic fracturing operations as well as the new family of fluids being developed for both traditional and unconventional reservoirs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40735.
Influence of the processing parameters and composition on the thermal stability of PLA/nanoclay bio‐nanocomposites
Authors: Iturrondobeitia Maider , Okariz Ana , Guraya Teresa , Zaldua Ane‐Miren , Ibarretxe Julen 
Published: April 2014

ABSTRACTPoly(lactic acid) (PLA) is one the most promising bio‐based and biodegradable polymer. However, its low thermal stability limits the range of applications and complicates its transformation via the most industrial common processes. The novelty of this work is studying the thermal stability of PLA and PLA/clay nanocomposites during use, as a function of the composition and using a wide range of extrusion and injection moulding processing parameters. To improve the thermal stability of the PLA, laminar silicates containing different organomodifications have been added (Cloisite 20A and Cloisite 30B). The results show that the processing conditions and composition define the morphology of the bio‐nanocomposites, which plays key role in defining final thermal properties of the material. In general, clays improve the thermal stability of the processed material, increasing the degradation temperature and decreasing the degradation rate under a wide range of processing conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40747.
Quasi‐Min‐Max Model Predictive Control for Image‐Based Visual Servoing with Tensor Product Model Transformation
Authors: Wang T. T. , Xie W. F. , Liu G. D. , Zhao Y. M. 
Published: April 2014

AbstractThis paper presents a novel image‐based visual servoing (IBVS) controller based on quasi‐min‐max model predictive control (MPC). By transforming the image Jacobian matrix (i.e. interaction matrix) into a convex combination of linear time‐invariant vertices form with the tensor‐product (TP) model transformation method, the visual servoing system is represented as a polytopic linear parameter‐varying (LPV) system. A robust controller is designed for the robotic visual servoing system subject to input and output constraints such as robot physical limitations and visibility constraints. The control signal is calculated online by carrying out the convex optimization involving linear matrix inequalities (LMIs) in model predictive control. The proposed visual servoing method avoids the inverse of the image Jacobian matrix and hence can solve the intractable problems for the classical IBVS controller, such as large displacements between the initial and the desired position of the camera. The ability of handling constraints can keep the image features in the boundary of the desired field of view (FOV). To verify the effectiveness of the proposed algorithm, the simulation results on a 6 degrees‐of‐freedom (DOF) robot manipulator with eye‐in‐hand configuration are presented and discussed.
From chemical platform molecules to new biosolvents: Design engineering as a substitution methodology
Authors: Bergez‐Lacoste Manon , Thiebaud‐Roux Sophie , De Caro Pascale , Fabre Jean‐François , Gerbaud Vincent , Mouloungui Zéphirin 
Published: April 2014

AbstractThe substitution of conventional solvents, in line with regulation changes, requires the use of appropriate methodologies able to generate candidate molecules. Starting from the widely used trial and error approach, we developed two improved, time‐ and cost‐saving methodologies, involving the prediction of molecule properties and reverse design. Reverse design is an innovative methodology to design biosolvents through a virtual laboratory: stages of generation of molecular structures and properties prediction are integrated into a computer‐aided molecular design tool providing solutions that meet targeted specifications. These two substitution methodologies were applied in a case study aiming at replacing acetone and methyl ethyl ketone for the solubilization of epoxy resin prepolymers. The generation of performing biosolvents was carried out from furfural as a bio‐based platform molecule, thanks to the prediction of different relevant properties (physico‐chemical, safety, and environmental characteristics). The reverse design succeeded in ranking these solvent candidates according to their capacity to match the required specifications.
Continuous antibody purification using precipitation: An important step forward
Authors: Velayudhan Ajoy 
Published: April 2014

AbstractRecent advances in cell culture have reduced upstream costs, and made downstream processing the more expensive component of biologics manufacturing. Within downstream processing, the chromatographic steps have usually been the most expensive, on the one hand because chromatographic steps are traditionally run in batch mode and on the other because resins are typically more expensive per unit mass of product than other bioproduct‐contact materials [1, 2]. There have been many attempts to consider alternatives to chromatography [3, 4], but the comparatively high resolution of chromatography, combined with the bioprocess industry's wealth of experience in using the various chromatographic modes, have made it hard to replace in a manufacturing setting. In this issue of Biotechnology Journal Hammerschmid et al. [5] make several original contributions to this discussion.
Seasonal Changes of Flavonoid Content in Melittis melissophyllum L. (Lamiaceae)
Authors: Skrzypczak‐Pietraszek Ewa , Pietraszek Jacek 
Published: April 2014

AbstractMelittis melissophyllum L., a medicinal plant currently used in the folk medicine, was analyzed for the content of flavonoid compounds. The plants were collected in two locations in Poland in May and September. MeOH Extracts from the leaves and flowers (separately) were analyzed by HPLC‐DAD. Eight compounds were identified in all the samples and quantitatively analyzed as cinaroside (=luteolin 7‐O‐glucoside), rutin, myricetin, quercitrin, quercetin, luteolin, kaempferol, and apigenin. M. melissophyllum accumulated the highest total amounts of flavonoids in May (flowers: from 258 to 271 mg/100 g dry weight (dw); leaves: from 143 to 155 mg/100 g dw) and significantly lower ones in September (leaves: from 83 to 92 mg/100 g dw). The main compound was cinaroside (May: up to 249 mg/100 g dw; September: up to 43 mg/100 g dw). Advanced multivariate statistical techniques (cluster analysis (CA) and principal component analysis (PCA)) were used to characterize the sample populations and to analyze the data. We report, for the first time, the results of the quantitative analysis of M. melissophyllum flavonoids and seasonal changes in their accumulation. Our results show that the time of harvesting has a significant influence on the flavonoid content in M. melissophyllum, while the geographical location does not have such an effect.
Further Antibacterial Geranium macrorrhizum L. Metabolites and Synthesis of Epoxygermacrones
Authors: Radulović Niko S. , Zlatković Dragan , Dekić Milan , Stojanović‐Radić Zorica 
Published: April 2014

Abstract4,5‐ and 1,10‐Epoxygermacrones were isolated from the essential oil of aerial parts of Geranium macrorrhizum L. (Geraniaceae). The structures of the epoxy derivatives were deduced from their 1D‐ and 2D‐NMR spectra, molecular modeling, and confirmed by synthesis starting from germacrone. The epoxy compounds were screened for their antimicrobial activities by a microdilution assay, which revealed high activities of both compounds against Bacillus subtilis (minimum inhibitory concentrations (M/Cs) determined were 4.3 and 43 nmol/ml for 1,10‐ and 4,5‐epoxygermacrone, resp.) and Pseudomonas aeruginosa (0.043 and 0.855 μmol/ml for 1,10‐ and 4,5‐epoxygermacrone, resp.). The discovery and observed activity of the two epoxides fills the gap in our knowledge of the active principles in this highly renowned ethnomedicinal plant species.
Limonoids from Azadirachta indica var. siamensis Extracts and Their Cytotoxic and Melanogenesis‐Inhibitory Activities
Authors: Manosroi Aranya , Kitdamrongtham Worapong , Ishii Kenta , Shinozaki Takuro , Tachi Yosuke , Takagi Mio , Ebina Kodai , Zhang Jie , Manosroi Jiradej , Akihisa Rima , Akihisa Toshihiro 
Published: April 2014

AbstractSix new limonoids, 7‐benzoyl‐17‐epinimbocinol (5), 3‐acetyl‐7‐tigloylnimbidinin (8), 1‐isovaleroyl‐1‐detigloylsalanninolide (15), 2,3‐dihydro‐3α‐methoxynimbolide (16), deacetyl‐20,21‐epoxy‐20,22‐dihydro‐21‐deoxyisonimbinolide (26), and deacetyl‐20,21,22,23‐tetrahydro‐20,22‐dihydroxy‐21,23‐dimethoxynimbin (27), along with 28 known limonoids, 1–4, 6, 7, 9–14, 17–25, and 28–34, and two known flavonoids, 35 and 36, have been isolated from the extracts of bark, leaves, roots, and seeds of Azadirachta indica A. Juss. var. siamensis Valeton (Siamese neem tree; Meliaceae). The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis and comparison with literature data. All of these compounds were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines. Eleven compounds, 1, 2, 4–7, 13, 16, 17, 29, and 30, exhibited potent cytotoxicities against one or more cell lines with IC50 values in the range of 0.1–9.3 μM. Compound 16 induced apoptotic cell death in AZ521 cells upon evaluation of the apoptosis‐inducing activity by flow cytometric analysis. Western blot analysis on AZ521 cells revealed that compound 16 activated caspases‐3, ‐8, and ‐9, while increasing the ratio of Bax/Bcl‐2. This suggested that 16 induced apoptosis via both mitochondrial and death receptor pathways in AZ521. In addition, upon evaluation of all compounds against the melanogenesis in B16 melanoma cells induced with α‐melanocyte‐stimulating hormone (α‐MSH), 20 limonoids, i.e., 1–3, 6, 9–11, 18, 19, 21–29, 32, and 34, and two flavonoids, 35 and 36, exhibited melanogenesis‐inhibitory activities, with no, or almost no, toxicities to the cells at lower and/or higher concentrations, which were more potent than the reference arbutin, a known melanogenesis inhibitor. Western blot analysis showed that nimbin (18) reduced the protein levels of microphtalmia‐associated transcription factor (MITF), tyrosinase, tyrosine‐related protein 1 (TRP‐1), and TRP‐2 mostly in a concentration‐dependent manner, indicating that 18 inhibits melanogenesis on a α‐MSH‐stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase, TRP‐1, and TRP‐2.
Air‐Core Size Measurement of Operating Hydrocyclone by Electrical Resistance Tomography
Authors: Rakesh Arugonda , Kumar Reddy Vakamalla T. S. R , Narasimha Mangadoddy 
Published: April 2014

AbstractElectrical resistance tomography (ERT) allows to measure hydrocyclone internal flow dynamics in situ. A dual‐plane high‐speed ERT system is proposed to map two‐phase distributions with varying operational parameters. Experimental results are presented in terms of air‐core diameter and its size variation for various feed flow rates and design variables. The total variation algorithm provides the best results compared to Tikhonov and Gauss‐Newton algorithms. The influence of finite element method mesh size on air‐core resolution is evaluated. High‐speed video imaging and a volume‐of‐fluid‐based two‐phase computational fluid dynamics (CFD) model are adopted to determine the air‐core size. Cross validation of air‐core size and shape is performed by ERT measurements with CFD simulations and high‐speed video imaging.
Ultrafine Grinding of Limestone with Sodium Polyacrylates as Additives in Ordinary Portland Cement Mortar
Authors: Ohenoja Katja , Breitung‐Faes Sandra , Kinnunen Päivö , Illikainen Mirja , Saari Juha , Kwade Arno , Niinimäki Jouko 
Published: April 2014

AbstractSodium polyacrylates permit a higher solids concentration during grinding, reducing the resulting particle size and/or specific energy consumption. Their impact on fine and ultrafine grinding of limestone was studied. Sodium polyacrylate with a low polydispersity index was found to be the most effective grinding aid for limestone and consequently applied for further nano‐grinding experiments. Nano‐grinding was most energy‐efficient with the smallest grinding medium size. These ground nano‐sized CaCO3 particles with sodium polyacrylate on the surface accelerated the hydration of ordinary Portland cement cement paste.