bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initiation of Carbon Nanofiber Growth on Polycrystalline Nickel Foam under Low Ethylene Pressure
Authors: Roemers‐van Beek Joline M. , Wang Zhu‐Jun , Rinaldi Ali , Willinger Marc G. , Lefferts Leon 
Published: March 2018

AbstractThe initiation of carbon nanofiber (CNF) growth on polycrystalline Ni foam was investigated by using a combination of ex situ and in situ methods, which include SEM, XRD, and Raman spectroscopy. Experiments were performed at a low hydrocarbon partial pressure to slow down the initiation process. Very little to no CNFs were observed on reduced samples, which is caused by diffusion of C to the bulk of the Ni foam. This prevents the formation of Ni3C as a precursor of Ni nanoparticles at a low hydrocarbon partial pressure from acting as active particles for CNF formation. CNF growth was significant on oxidized samples and the initiation was slowed down by using an extremely low ethylene pressure. Ni nanoparticles are able to catalyze CNF growth, provided these are isolated from the Ni bulk by unreduced NiO, which results from the incomplete reduction of the NiO layer.
Lithium Extracting from Zinnwaldite: Economical Comparison of an Adapted Spodumene and a Direct‐Carbonation Process
Authors: Rentsch Lars , Martin Gunther , Bertau Martin , Höck Michael 
Published: March 2018

AbstractLithium is used in a variety of everyday objects. The most important field of application is as components of battery electrolytes and electrodes. Next to salar brines, commercial lithium production relies on mineral ore sources such as spodumene, petalite, and lepidolite. This study provides an economic comparison of two processes for the extraction of lithium from zinnwaldite concentrate, a lithium mineral that can be found along the Czech/German border at Cínovec/Zinnwald. In contrast to the state‐of‐the‐art lithium extraction from siliceous ores, which is a hydrometallurgical extraction process with sulfuric acid, the novel direct‐carbonation process is based on digestion using supercritical carbon dioxide. An assessment of the capital and operating expenditures was also carried out.
Monitoring Lactose Crystallization at Industrially Relevant Concentrations by Photon Density Wave Spectroscopy
Authors: Hartwig Anne , Hass Roland 
Published: March 2018

AbstractLactose is of great industrial importance and its production includes the cooling crystallization from highly concentrated solutions. Monitoring the crystallization process is essential to ensure reproducible product quality. Photon density wave (PDW) spectroscopy enables in‐line monitoring of highly concentrated processes in liquid dispersions. It was applied to the determination of the solubility and nucleation points of lactose monohydrate in water, sizing of lactose crystals, and to dissolution as well as crystallization monitoring. Other process analytical technologies (focused‐beam reflectance measurement, particle vision and measurement) were used as reference, and the comparison indicates that PDW spectroscopy is very robust against probe fouling and is, thus, a useful tool for monitoring crystallization processes in concentrated suspensions.
CuP2/C Composite Negative Electrodes for Sodium Secondary Batteries Operating at Room‐to‐Intermediate Temperatures Utilizing Ionic Liquid Electrolyte
Authors: Kaushik Shubham , Hwang Jinkwang , Matsumoto Kazuhiko , Sato Yuta , Hagiwara Rika 
Published: March 2018

AbstractA copper phosphide/carbon (CuP2/C) composite was synthesized by using a two‐step ball‐milling process from copper metal and red phosphorous and investigated as a negative electrode for a sodium secondary battery using Na[FSA]−[C3C1pyrr][FSA] [FSA=bis(fluorosulfonyl)amide anion and C3C1pyrr=N‐methyl‐N‐propylpyrrolidinium cation] ionic liquid as the electrolyte. Operation at an intermediate temperature of 363 K revealed that the aforementioned composite showed a large reversible capacity of 595 mAh g−1 at 100 mA g−1 and a high rate capability with a capacity retention of 65 % (366 mAh g−1) at a high current density of 8000 mA g−1. Cyclability tests confirmed that 71.0 % of the initial capacity was retained at the 200th cycle with 99.5 % coulombic efficiency at 500 mA g−1. The CuP2/C composite forms a solid‐electrolyte interphase layer during the initial charging step and becomes amorphous after the initial charge‐discharge cycle at 363 K.
Structure of Nanoparticles Derived from Designer Surfactant TPGS‐750‐M in Water, As Used in Organic Synthesis
Authors: Andersson Martin P. , Gallou Fabrice , Klumphu Piyatida , Takale Balaram S. , Lipshutz Bruce H. 
Published: March 2018

AbstractUsing density functional theory and the COSMO‐RS implicit solvent model, we predict the structure and physical chemical properties of nanomicelles derived from the designer surfactant TPGS‐750‐M used in organic synthesis. We predict that the influence of chain length of the PEG region is low, while the termination of the PEG chain (‐OH vs.‐OCH3) plays a very large role. The interfacial tension is considerably lower between the micellar and water phases for the ‐OH than the ‐OCH3 terminated surfactant, and our calculations reproduce the large difference observed in average particle size as a function of PEG chain termination. We propose a structure for the nanoparticles formed by TPGS‐750‐M in water that is consistent with a ≈50 nm average diameter, which is significantly larger than a single micelle. According to the calculations, each nanoparticle would consist of 30–40 aggregated TPGS‐750‐M micelles forming a compartmentalized nanoparticle, with considerable amounts of water in the PEG region. The whole particle is stabilized by vitamin E succinate at the nanoparticle‐water interface. In the presence of Zn dust or powder, the surfactant collides with the Zn surface, and by interactions with the hydrophobic inner cores, form organozinc species that are protected from the surrounding water. This explains why highly moisture‐sensitive Negishi‐like couplings take place in surfactant–water systems.
A General, Rhodium‐Catalyzed, Synthesis of Deuterated Boranes and N‐Methyl Polyaminoboranes
Authors: Colebatch Annie L. , Hawkey Gilder Benjamin W. , Whittell George R. , Oldroyd Nicola L. , Manners Ian , Weller Andrew S. 
Published: March 2018

AbstractThe rhodium complex [Rh(Ph2PCH2CH2CH2PPh2)(η6‐FC6H5)][BArF4], 2, catalyzes BH/BD exchange between D2 and the boranes H3B⋅NMe3, H3B⋅SMe2 and HBpin, facilitating the expedient isolation of a variety of deuterated analogues in high isotopic purities, and in particular the isotopologues of N‐methylamine‐borane: R3B⋅NMeR2 1‐dx (R=H, D; x=0, 2, 3 or 5). It also acts to catalyze the dehydropolymerization of 1‐dx to give deuterated polyaminoboranes. Mechanistic studies suggest a metal‐based polymerization involving an unusual hybrid coordination insertion chain‐growth/step‐growth mechanism.
Serum uric acid to creatinine ratio correlates with β‐cell function in type 2 diabetes
Authors: Li Minchao , Gu Liubao , Yang Jun , Lou Qinglin 
Published: March 2018

AbstractBackgroundThe correlation between serum uric acid (SUA) and β‐cell function remains controversial. The present study aims to use a new index, renal function‐normalized SUA, to observe its correlation with β‐cell function in patients with type 2 diabetes (T2DM).MethodsA total of 713 patients with T2DM received standard 75‐g oral glucose tolerance and insulin release test. Renal function‐normalized SUA was calculated using SUA/creatinine and β‐cell function was assessed by HOMA‐B. Binary logistic regression analysis was used to estimate the association between SUA/creatinine and β‐cell function.ResultsThere are positive correlations between SUA/creatinine and HOMA‐B (r = 0.143, P < 0.001), as well as other indexes of β‐cell function including modified β‐cell function index (r = 0.104, P = 0.007), InsAUC30 (r = 0.100, P = 0.008), and InsAUC120 (r = 0.124, P = 0.001). SUA/creatinine also positively correlates with insulin resistance (HOMA‐IR: r = 0.161, P < 0.001). Moreover, multivariate analysis revealed that SUA/creatinine was significantly associated with preserved β‐cell function, independently of potential confounders including sex, BMI, and renal function.ConclusionsSUA to creatinine ratio correlates with β‐cell function in T2DM patients.
Modeling the spatial and temporal dynamics of riparian vegetation induced by river flow fluctuation
Authors: You Xiaoguang , Liu Jingling 
Published: March 2018

AbstractRiver flow fluctuation has an important influence on riparian vegetation dynamics. A temporally segmented stochastic model focusing on a same‐aged population is developed for the purpose of describing both spatial and temporal dynamics of riparian vegetation. In the model, the growth rate of population, rather than carrying capacity, is modeled as the random variable. This model has explicit physical meaning. The model deduces a process‐based solution. From the solution process, the probability density of spatial distribution can be derived; therefore, the spatial distribution of population abundance can be described. The lifespan of a same‐aged population and the age structure of the species‐specific population can also be studied with the aid of this temporally segmented model. The influence of correlation time of river flow fluctuation is also quantified according to the model. The calibration of model parameters and model application are discussed. The model provides a computer‐aided method to simulate and predict vegetation dynamics during river flow disturbances. Meanwhile, the model is open and allows for more accurate and concrete modeling of growth rate. Because of the Markov property involved in the process‐based solution, the model also has the ability to deal with cases of nonstationary disturbances.
Temporal variation in trophic relationships among three congeneric penguin species breeding in sympatry
Authors: Tarroux Arnaud , Lydersen Christian , Trathan Philip N. , Kovacs Kit M. 
Published: March 2018

AbstractPenguins are a monophyletic group in which many species are found breeding sympatrically, raising questions regarding how these species coexist successfully. Here, the isotopic niche of three sympatric pygoscelid penguin species was investigated at Powell Island, South Orkney Islands, during two breeding seasons (austral summers 2013–2014 and 2015–2016). Measurements of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios were obtained from blood (adults) or feather (chicks) samples collected from Adélie Pygoscelis adeliae, chinstrap P. antarctica, and gentoo P. papua penguins. Isotopic niche regions (a proxy for the realized trophic niches) were computed to provide estimates of the trophic niche width of the studied species during the breeding season. The isotopic niche regions of adults of all three species were similar, but gentoo chicks had noticeably wider isotopic niches than the chicks of the other two species. Moderate to strong overlap in isotopic niche among species was found during each breeding season and for both age groups, suggesting that the potential for competition for shared food sources was similar during the two study years, although the actual level of competition could not be determined owing to the lack of data on resource abundance. Clear interannual shifts in isotopic niche were seen in all three species, though of lower amplitude for adult chinstrap penguins. These shifts were due to variation in carbon, but not nitrogen, isotopic ratios, which could indicate either a change in isotopic signature of their prey or a switch to an alternative food web. The main conclusions of this study are that (1) there is a partial overlap in the isotopic niches of these three congeneric species and that (2) they responded similarly to changes that likely occurred at the base of their food chain between the 2 years of the study.
Positive severity feedback between consecutive fires in dry eucalypt forests of southern Australia
Authors: Barker James W. , Price Owen F. 
Published: March 2018

AbstractFire regimes have long‐term effects on ecosystems which can be subtle, requiring study at a large spatial scale and temporal scale to fully appreciate. The way in which multiple fires interact to create a fire regime is poorly understood, and the relationship between the severities of consecutive fires has not been studied in Australia. By overlaying remotely sensed severity maps, our study investigated how the severity of a fire is influenced by previous fire severity. This was done by sampling points at 500‐m spacing across 53 fires in dry eucalypt forests of southeast Australia, over a range of time since fire spanning every major fire season for 30 yr. Generalized additive models were used to determine the influence of previous severity on the probability of crown fire and understory fire, controlling for differences in time since fire, topography, and weather. We found that a crown fire is more than twice as likely after a previous crown fire than previous understory fire, and understory fire is more likely after previous understory fire. Our findings are in line with the results of studies from North America and suggest that severe fire promotes further fire. This may be evidence of a runaway positive feedback, which can drive ecological change, and lead to a mosaic of divergent vegetation, but research into more than two consecutive fires is needed to explore this. Our results also suggest that a low‐severity prescribed fire may be a useful management option for breaking a cycle of crown fires.
MiR221 promotes precursor B‐cell retention in the bone marrow by amplifying the PI3K‐signaling pathway in mice
Authors: Petkau Georg , Kawano Yohei , Wolf Ingrid , Knoll Marko , Melchers Fritz 
Published: March 2018

AbstractHematopoietic stem cells and lineage‐uncommitted progenitors are able to home to the bone marrow upon transplantation and reconstitute the host with hematopoietic progeny. Expression of miR221 in B‐lineage committed preBI‐cells induces their capacity to home to the bone marrow. However, the molecular mechanisms underlying miR221‐controlled bone marrow homing and retention remain poorly understood. Here, we demonstrate, that miR221 regulates bone marrow retention of such B‐cell precursors by targeting PTEN, thus enhancing PI3K signaling in response to the chemokine CXCL12. MiR221‐enhanced PI3K signaling leads to increased expression of the anti‐apoptotic protein Bcl2 and VLA4 integrin‐mediated adhesion to VCAM1 in response to CXCL12 in vitro. Ablation of elevated PI3K activity abolishes the retention of miR221 expressing preBI‐cells in the bone marrow. These results suggest that amplification of PI3K signaling by miR221 could be a general mechanism for bone marrow residence, shared by miR221‐expressing hematopoietic cells.
Superstars are not necessarily role models: Morality perceptions moderate the impact of competence perceptions on supervisor role modeling
Authors: Peters Kim , Steffens Niklas K. , Morgenroth Thekla 
Published: March 2018

AbstractThere is a general assumption that we choose role models from the ranks of those who have demonstrated extraordinary competence. However, the person perception literature supports the expectation that morality may also matter, and that we may be most likely to role model competent individuals if we also believe that they have good moral character. To test this possibility, we conducted four studies of adults’ role modeling of workplace supervisors. Study 1 (N = 245) and Study 2 (N = 110) showed that workplace supervisors’ perceived competence was most strongly associated with role model perceptions when the supervisor was also seen as moral. Study 3 (N = 492) and 4 (N = 335) replicated these findings with pre‐registered experiments, and revealed indirect effects of supervisor attributes on role modeling through emulation. Results suggest that we choose organizational role models who have achieved success in ways that are in line with our moral values.
Secular changes in severity of intellectual disability in tuberous sclerosis complex: A reflection of improved identification and treatment of epileptic spasms?
Authors: Tye Charlotte , Thomas Laura E. , Sampson Julian R. , Lewis Julia , O'Callaghan Finbar , Yates John R. W. , Bolton Patrick F. 
Published: March 2018

SummaryTuberous sclerosis complex (TSC) is a multisystem genetic disorder caused by mutations in TSC1 or TSC2. Epilepsy occurs in 80%‐90% of affected individuals during their lifetime, and up to one‐third of children with TSC will develop epileptic (infantile) spasms, for which vigabatrin has been shown to be particularly effective. Epilepsy severity and epileptic spasms are consistent markers of risk for the development of intellectual impairment in TSC. Although previous studies demonstrate a bimodal distribution of intellectual ability in TSC, recent findings suggest a unimodal distribution, which may reflect a change in IQ distribution over time. We compared 3 large historical UK cohorts of TSC (n = 331) that show varied distributions of intellectual ability, first ruling out differences in study methodology. Later‐born individuals had a higher frequency of reported spasms and higher likelihood of vigabatrin administration, but were less likely to have profound intellectual impairment, compared to the earlier‐born individuals. Our findings suggest that epileptic spasms went undetected in the older patients and therefore were not treated, leading to a higher occurrence of profound impairment, whereas the later born cohort had better access to treatment. These findings support the importance of early identification and treatment of seizures in TSC.
Tuning carbon dioxide capture capability with structural and compositional design in mmen‐(Mg,Zn) (dobpdc) metal‐organic framework: density functional theory investigation
Authors: Pramchu Sittichain , Jaroenjittichai Atchara P. , Laosiritaworn Yongyut 
Published: March 2018

AbstractThis paper presents a materials design for tuning the CO2‐capture capability of mixed‐metal‐organic framework mmen‐(ZnxMg1‐x)2(dobpdc) using density functional theory. The structural stability of a mixed‐metal structure with respect to its parent single‐metal species was investigated via energy of mixing (ΔEmix). We found that the ΔEmix of all mixed‐metal structures are negative, signifying exothermic mixing. This then indicates that mixed‐metal structures are energetically preferable compared with their non‐interacting single‐metal species. Moreover, the magnitudes of ΔEmix of all mixed‐metal structures are lower than 1 kJ/mol, implying an ‘ideal mixing’. Density‐of‐state analysis also reveals that the electronic structures of both Mg and Zn in mixed‐metal structures are not significantly different from those in parent single‐metal species, suggesting weak chemical interaction between Mg and Zn in mixed‐metal structures. For CO2‐adsorbed mmen‐(ZnxMg1‐x)2(dobpdc), we found that the adsorption energy (Eads) is a linear function of mixing ratio (x), and does not depend on how Mg and Zn atoms are arranged in forming different mixed‐metal structures. This can be described by the weak chemical interaction between Mg and Zn in a mixed‐metal structure. Consequently, Eads can then be predicted conveniently from the mixing ratio, while the adsorption properties of parent single‐metal species can be tuned with the proposed mixed‐metal method. We then expect that the knowledge of materials design using a mixed‐metal approach presented in this work would benefit the community in providing the ability to tune CO2 capture capability efficiently in the materials studied. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.
Catalytic coupling of CH4 with CHF3 for the synthesis of VDF over LaOF catalyst
Authors: Cheng Yimin , Wang Jinchao , Han Wenfeng , Song Yanyan , Liu Wucan , Yang Luteng , Wang Shucheng , Wu Zhixing , Tang Haodong , Zhang Jianjun , Stockenhuber Michael , Kennedy Eric M. 
Published: March 2018

AbstractThe oxidative coupling of methane (OCM) with CHF3 facilitates the synthesis of vinylidene fluoride (VDF). The aim is to utilize CHF3, which is otherwise considered a waste with a very high global warming potential. This study focuses on the effect of a LaOF catalyst on OCM occurring in the presence of CHF3, which engenders a promoting effect of O2 on CH4 activation. It examines the structural and phase changes of the lanthanum catalyst during the reaction and then speculates on the reaction mechanism. In combining OCM with CHF3, both the conversion of CH4 and the formation rate of VDF are almost tripled at 700°C. However, at higher temperatures, gas‐phase reactions play a dominating role in the conversion of CH4 and LaOF catalyst plays a very minor role in the reaction system at elevated temperatures. Irrespective of the reaction temperature, VDF is produced via the gas‐phase coupling of CH3 radicals with CF2. During pretreatment or during the reaction itself, La2O3 is fluorinated by CHF3 and HF, yielding the formation of surface LaOF and LaF3 species. LaF3 is a relatively inactive catalyst for CH4 conversion, whereas, in comparison LaOF appears to play a very important role in the activation of CH4 at low temperatures. The activation mechanism of CH4 at relatively low temperatures is similar with that postulated to occur during the OCM. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.
Hydrothermal activity in the fourth member of the Triassic Leikoupo Formation in the Yuanba area, northeast Sichuan, SW China
Authors: Zhong Yi‐Jiang , Chen An‐Qing , Huang Ke‐Ke , Yang Shuai , Xu Sheng‐Lin 
Published: March 2018

Large quantities of saddle dolomite, dolomite, calcite, celestite, fluorite, barite, quartz, and pyrite occur as fracture fillings in the fourth member of the Middle Triassic Leikoupo Formation in the Yuanba area, northeast Sichuan. They were found either as single mineral or mineral assemblages. The properties, origin, and evolution of the fluids from which these fracture fillings were precipitated were studied using a variety of methods, including polarized light microscopy, cathodoluminescence microscopy, fluid inclusions, and stable isotope analysis. Homogenization temperatures of the liquid–gas inclusions trapped within the dolomite ranged from 112 to 138 °C. Based on this temperature range and the oxygen isotope data, the δ18O values of the fluids from which the dolomite precipitated were determined to be between −5‰ and 7‰ (Standard Mean Ocean Water). The study suggests that the fracture‐filling dolomite, ubiquitous in the fourth member of the Middle Triassic Leikoupo Formation in the study area, was produced from high‐temperature, high‐salinity brines. These brines were interpreted to have originated from the mixtures of hot brines trapped in rock formations and hydrothermal fluids from deep sources and to have become enriched in strontium during diagenesis.