bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of the Chromophore in the Apatite Pigment [Sr10(PO4)6(CuxOH1−x−y)2]: Linear OCuO− Featuring a Resonance Raman Effect, an Extreme Magnetic Anisotropy, and Slow Spin Relaxation
Authors: Kazin Pavel E. , Zykin Mikhail A. , Zubavichus Yan V. , Magdysyuk Oxana V. , Dinnebier Robert E. , Jansen Martin 
Published: November 2013

AbstractA new chromophore has been identified in copper‐doped apatite pigments having the general composition [Sr10(PO4)6(CuxOH1−x−y)2], in which x=0.1, 0.3 and y=0.01–0.42. By using X‐ray absorption spectroscopy, low‐temperature magnetization measurements, and synchrotron X‐ray powder structure refinement, it has been shown that the oxygenated compounds contain simultaneously diamagnetic Cu1+ and paramagnetic Cu3+ with S=1. Cu3+ is located at the same crystallographic position as Cu1+, being linearly coordinated by two oxygen atoms and forming the OCuO− anion. The Raman spectroscopy study of [A10(PO4)6(CuxOH1−x−y)2,], in which A=Ca, Sr, Ba, reveals resonance bands at 651–656 cm−1 assigned to the symmetric stretching vibration (ν1) of OCuO−. The strontium apatite pigment exhibits a strong paramagnetic anisotropy with an unprecedentedly large negative zero‐field splitting parameter (D) of ≈−400 cm−1. The extreme magnetic anisotropy causes slow magnetization relaxation with relaxation times (τ) up to 0.3 s at T=2 K, which relates the compounds to single‐ion magnets. At low temperature, τ is limited by a spin quantum‐tunneling, whereas at high temperature a thermally activated relaxation prevails with Ueff≈48 cm−1. Strong dependence of τ on the paramagnetic center concentration at low temperature suggests that the spin‐spin relaxation dominates in the spin quantum‐tunneling process. The compound is the first example of a d‐metal‐based single‐ion magnet with S=1, the smallest spin at which an energy barrier arises for the spin flipping.
Exo‐Dig Radical Cascades of Skipped Enediynes: Building a Naphthalene Moiety within a Polycyclic Framework
Authors: Pati Kamalkishore , Hughes Audrey M. , Phan Hoa , Alabugin Igor V. 
Published: November 2013

AbstractCascade radical transformations of acyclic precursors open efficient, convenient and atom‐economical access to functionalized compounds of increased structural complexity. This report describes a selective sequence of 5‐exo‐dig and 6‐exo‐dig cyclizations followed by attack at a pendant aromatic moiety and rearomatization.
Discovery of 7‐Aryl‐Substituted (1,5‐Naphthyridin‐4‐yl)ureas as Aurora Kinase Inhibitors
Authors: Defaux Julien , Antoine Maud , Le Borgne Marc , Schuster Tilmann , Seipelt Irene , Aicher Babette , Teifel Michael , Günther Eckhard , Gerlach Matthias , Marchand Pascal 
Published: November 2013

AbstractAs part of our research projects to identify new chemical entities of biological interest, we developed a synthetic approach and the biological evaluation of (7‐aryl‐1,5‐naphthyridin‐4‐yl)ureas as a novel class of Aurora kinase inhibitors for the treatment of malignant diseases based on pathological cell proliferation. 1,5‐Naphthyridine derivatives showed excellent inhibitory activities toward Aurora kinases A and B, and the most active compound, 1‐cyclopropyl‐3‐[7‐(1‐methyl‐1H‐pyrazol‐4‐yl)‐1,5‐naphthyridin‐4‐yl]urea (49), displayed IC50 values of 13 and 107 nM against Aurora kinases A and B, respectively. In addition, the selectivity toward a panel of seven cancer‐related protein kinases was highlighted. In vitro ADME properties were also determined in order to rationalize the difficulties in correlating antiproliferative activity with Aurora kinase inhibition. Finally, the good safety profile of these compounds imparts promising potential for their further development as anticancer agents.
Presence of symptom clusters in surgically treated patients with esophageal cancer: Implications for survival
Authors: Wikman Anna , Johar Asif , Lagergren Pernilla 
Published: November 2013

BACKGROUNDIt is not known whether symptoms cluster together after esophageal cancer surgery or whether such symptom clusters are associated with survival in patients with esophageal cancer who are treated surgically.METHODSData from a prospective Swedish nationwide cohort study of surgically treated patients with esophageal cancer recruited between 2001 and 2005 were used. General and esophageal cancer‐specific symptoms were assessed using the European Organization for Research and Treatment of Cancer QLQ‐C30 quality of life questionnaire and the QLQ‐OES18 module at 6 months after surgery. Associations between symptom clusters and survival were analyzed using Cox proportional hazards models, providing hazards ratios with 95% confidence intervals, adjusted for other known prognostic factors.RESULTSAmong 402 patients reporting symptoms 6 months after surgery, 3 symptom clusters were identified. The first symptom cluster (“fatigue/pain”) was characterized by symptoms of pain, fatigue, insomnia, and dyspnea and was present in 30% of patients. The second symptom cluster (“reflux/cough”) was characterized by symptoms of dry mouth, problems with taste, coughing, and reflux and was present in 27% of patients. The third symptom cluster (“eating difficulties”) was characterized by appetite loss, dysphagia, eating difficulties, and nausea/vomiting and was present in 28% of patients. The presence of the reflux/cough and eating difficulties symptom clusters was associated with a statistically significantly increased risk of mortality (adjusted hazards ratio, 1.43 [95% confidence interval, 1.08‐1.89] and adjusted HR, 1.41 [95% confidence interval, 1.06‐1.87], respectively).CONCLUSIONSSymptoms experienced by surgically treated patients with esophageal cancer appear to cluster together, and the presence of these symptom clusters appears to have strong prognostic value. Cancer 2014;120:286–293. © 2013 American Cancer Society.
Hippocampal neuropathology of domoic acid–induced epilepsy in California sea lions (Zalophus californianus)
Authors: Buckmaster Paul S. , Wen Xiling , Toyoda Izumi , Gulland Frances M.D. , Van Bonn William 
Published: November 2013

ABSTRACTCalifornia sea lions (Zalophus californianus) are abundant human‐sized carnivores with large gyrencephalic brains. They develop epilepsy after experiencing status epilepticus when naturally exposed to domoic acid. We tested whether sea lions previously exposed to DA (chronic DA sea lions) display hippocampal neuropathology similar to that of human patients with temporal lobe epilepsy. Hippocampi were obtained from control and chronic DA sea lions. Stereology was used to estimate numbers of Nissl‐stained neurons per hippocampus in the granule cell layer, hilus, and pyramidal cell layer of CA3, CA2, and CA1 subfields. Adjacent sections were processed for somatostatin immunoreactivity or Timm‐stained, and the extent of mossy fiber sprouting was measured stereologically. Chronic DA sea lions displayed hippocampal neuron loss in patterns and extents similar but not identical to those reported previously for human patients with temporal lobe epilepsy. Similar to human patients, hippocampal sclerosis in sea lions was unilateral in 79% of cases, mossy fiber sprouting was a common neuropathological abnormality, and somatostatin‐immunoreactive axons were exuberant in the dentate gyrus despite loss of immunopositive hilar neurons. Thus, hippocampal neuropathology of chronic DA sea lions is similar to that of human patients with temporal lobe epilepsy. J. Comp. Neurol. 522:1691–1706, 2014. © 2013 Wiley Periodicals, Inc.
Pharmacokinetics and comparative bioavailability of allopurinol formulations in healthy subjects
Authors: Helmy Sally A. , El‐Bedaiwy Heba M. 
Published: November 2013

AbstractAllopurinol is the most commonly used urate‐lowering therapy in gout. This study was undertaken to evaluate the pharmacokinetics and relative bioavailability of two brands of allopurinol tablets. The in vivo study was established according to a single‐center, randomized, single‐dose, laboratory‐blinded, Two Way, Cross‐Over Study with a washout period of 1 week. Under fasting conditions, 24 healthy male volunteers were randomly allocated to receive a single oral dose (200 mg) of either test and reference formulations. Plasma samples were obtained over a 6‐hour interval and analyzed for allopurinol by reversed phase liquid chromatography with ultraviolet detection. The 90% confidence intervals for the ratio of log transformed values of Cmax, AUC0–t, and AUCt–∞ of the two treatments were within the acceptable range (0.8–1.25) for bioequivalence. From PK perspectives, the two allopurinol formulations were considered bioequivalent, based on the rate and extent of absorption. No adverse events occurred or were reported after a single 200‐mg allopurinol and both formulations were well tolerated.
Indenyl Effect Due to Metal Slippage? Computational Exploration of Rhodium‐Catalyzed Acetylene [2+2+2] Cyclotrimerization
Authors: Orian Laura , Swart Marcel , Bickelhaupt F. Matthias 
Published: November 2013

AbstractThe mechanism of CpRh (Cp=cyclopentadienyl) and IndRh (Ind=indenyl)‐catalyzed acetylene [2+2+2] cyclotrimerization has been revisited aiming at finding an explanation for the better performance of the latter catalyst found experimentally. The hypothesis that an ancillary ligand of the precatalyst remains bonded to the metal center throughout the whole catalytic cycle, based on the experimental evidence that the nature of this ligand can exert some control in cocyclotrimerization of different alkynes, is considered. Strong hapticity variations occur in both the CpRh‐ and IndRh‐catalyzed processes. As the Ind ligand undergoes a more facile slippage than Cp, the energy profile is far smoother in the IndRh‐catalyzed cyclotrimerization. This difference in the energetics of the process translates into an enhanced activity of the IndRh catalyst, in nice agreement with experiment.
Reduction Mechanism of Fluoroethylene Carbonate for Stable Solid–Electrolyte Interphase Film on Silicon Anode
Authors: Chen Xilin , Li Xiaolin , Mei Donghai , Feng Ju , Hu Mary Y. , Hu Jianzhi , Engelhard Mark , Zheng Jianming , Xu Wu , Xiao Jie , Liu Jun , Zhang Ji‐Guang 
Published: November 2013

AbstractFluoroethylene carbonate (FEC) is an effective electrolyte additive that can significantly improve the cycling ability of silicon and other anode materials. However, the fundamental mechanism of this improvement is still not well understood. Based on the results obtained from 6Li NMR and X‐ray photoelectron spectroscopy studies, we propose a molecular‐level mechanism for how FEC affects the formation of solid electrolyte interphase (SEI) film: 1) FEC is reduced through the opening of the five‐membered ring leading to the formation of lithium poly(vinyl carbonate), LiF, and some dimers; 2) the FEC‐derived lithium poly(vinyl carbonate) enhances the stability of the SEI film. The proposed reduction mechanism opens a new path to explore new electrolyte additives that can improve the cycling stability of silicon‐based electrodes.
Size‐ and Shape‐Controlled Synthesis of Hexagonal Bipyramidal Crystals and Hollow Self‐Assembled Al‐MOF Spheres
Authors: Sarawade Pradip , Tan Hua , Anjum Dalaver , Cha Dongkyu , Polshettiwar Vivek 
Published: November 2013

AbstractWe report an efficient protocol for the synthesis of monodisperse crystals of an aluminum (Al)‐based metal organic framework (MOF) while obtaining excellent control over the size and shape solely by tuning of the reaction parameters without the use of a template or structure‐directing agent. The size of the hexagonal crystals of the Al‐MOF can be selectively varied from 100 nm to 2000 nm by simply changing the reaction time and temperature via its nucleation‐growth mechanism. We also report a self‐assembly phenomenon, observed for the first time in case of Al‐MOF, whereby hollow spheres of Al‐MOF were formed by the spontaneous organization of triangular sheet building blocks. These MOFs showed broad hysteresis loops during the CO2 capture, indicating that the adsorbed CO2 is not immediately desorbed upon decreasing the external pressure and is instead confined within the framework, which allows for the capture and subsequent selective trapping of CO2 from gaseous mixtures.
Referenced Capacitively Coupled Conductivity Detector for Capillary Electrophoresis
Authors: Stojkovic Marko , Schlensky Boris , Hauser Peter C. 
Published: November 2013

AbstractA dual capacitively coupled contactless conductivity detector for capillary electrophoresis was developed. The two channels are arranged in a bridge configuration so that one of them acts as a reference whose signal is subtracted. This effectively compensates for the baseline conductivity of the separation buffer so that the electronic zero setting is not necessary. Changes in the buffer composition are automatically accounted for, as are temperature drifts. The system is demonstrated for the detection of inorganic model cations in capillary electrophoresis. Besides the use with two separate capillaries, one of which solely serves as reference, it was also found possible to use a single capillary which is looped back through the reference cell.
Large‐volume sample stacking with polarity switching for monitoring of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) reactions by capillary electrophoresis
Authors: Lee Sang‐Yong , Müller Christa E. 
Published: November 2013

Nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) is a membrane glycoprotein involved in the hydrolysis of extracellular nucleotides. Its main substrate is ATP yielding AMP and pyrophosphate. NPP1 has been proposed as a novel drug target, for diabetes type 2 and the treatment of calcium pyrophosphate dihydrate deposition disease leading to inflammatory arthritis. The monitoring of NPP1 reactions is difficult because its velocity is very slow requiring highly sensitive analytical procedures. In this study, a method of large‐volume sample stacking with polarity switching was developed, and separations were optimized. Large sample volumes were loaded by hydrodynamic injection (5 psi, 13 s) followed by removal of a large plug of sample matrix from the capillary using polarity switching (−10 kV). The stacked analytes were subsequently separated in phosphate buffer (100 mM, pH 9.2) at 20 kV. The validated method was found to be linear (R2 = 0.9927) in the concentration range of 0.05–50 μM of AMP, with high accuracy and precision. The determined LOD and LOQ of AMP were 18 nM and 60 nM, respectively. Compared to a previously reported CE procedure using sweeping technique, a fivefold improvement of sensitivity was achieved. Moreover, the new technique was faster, and reproducibility of migration times was improved (RSD value = 1.2%). Importantly, adenine nucleotide analogs and derivatives tested as NPP1 inhibitors could be completely separated from the substrate ATP and the enzymatic product AMP. The method was applied to NPP1 inhibition assays investigating nucleotide‐derived inhibitors in the presence of ATP.
Acute toxicity of the cationic surfactant C12-benzalkonium in different bioassays: How test design affects bioavailability and effect concentrations
Authors: Chen Yi , Geurts Marc , Sjollema Sascha B. , Kramer Nynke I. , Hermens Joop L.M. , Droge Steven T.J. 
Published: November 2013

Abstract

Using an ion-exchange–based solid-phase microextraction (SPME) method, the freely dissolved concentrations of C12-benzalkonium were measured in different toxicity assays, including 1) immobilization of Daphnia magna in the presence or absence of dissolved humic acid; 2) mortality of Lumbriculus variegatus in the presence or absence of a suspension of Organisation for Economic Co-Operation and Development (OECD) sediment; 3) photosystem II inhibition of green algae Chlorella vulgaris; and 4) viability of in vitro rainbow trout gill cell line (RTgill-W1) in the presence or absence of serum proteins. Furthermore, the loss from chemical adsorption to the different test vessels used in these tests was also determined. The C12-benzalkonium sorption isotherms to the different sorbent phases were established as well. Our results show that the freely dissolved concentration is a better indicator of the actual exposure concentration than the nominal or total concentration in most test assays. Daphnia was the most sensitive species to C12-benzalkonium. The acute Daphnia and Lumbriculus tests both showed no enhanced toxicity from possible ingestion of sorbed C12-benzalkonium in comparison with water-only exposure, which is in accordance with the equilibrium partitioning theory. Moreover, the present study demonstrates that commonly used sorbent phases can strongly affect bioavailability and observed effect concentrations for C12-benzalkonium. Even stronger effects of decreased actual exposure concentrations resulting from sorption to test vessels, cells, and sorbent phases can be expected for more hydrophobic cationic surfactants. Environ Toxicol Chem 2014;33:606–615. © 2013 SETAC
Polychlorinated biphenyl profiles in ringed seals (Pusa Hispida) reveal historical contamination by a military radar station in Labrador, Canada
Authors: Brown Tanya M. , Fisk Aaron T. , Helbing Caren C. , Reimer Ken J. 
Published: November 2013

Abstract

Significant amounts of soil contaminated with polychlorinated biphenyls (PCBs) were discovered at a military radar station in Saglek Bay, Labrador, Canada, in 1996. Subsequent work showed elevated PCB concentrations in local marine sediments, in the benthic-associated food web, and in some ringed seals (Pusa hispida). The benthic-associated food web clearly reflected local PCB contamination, but the high PCB concentrations found in some ringed seals remained unexplained. In the present study, the authors assess the extent to which this local PCB source at Saglek Bay is contributing to the contamination of ringed seals in northern Labrador. Among 63 ringed seals sampled along the northern Labrador coast, 5 (8%) had PCB levels that were higher than recorded anywhere else in the Canadian Arctic. In addition, compared with seals exhibiting a long-range signal, 45% and 60% of subadults and adult males, respectively, exhibited heavier PCB congener profiles as characterized by principal components analysis, &gt;1.6-fold higher PCB/organochlorine pesticides ratios, and higher PCB concentration-weighted average log octanol–water partition coefficient values, consistent with a local source. Despite the spatially confined nature of contaminated sediments in Saglek Bay, the influence of this PCB source is not inconsequential; PCB concentrations in locally contaminated adult males are 2-fold higher than concentrations in those exposed only to long-range PCB sources and exceed an established threshold of 1.3 mg/kg for adverse health effects in seals. Environ Toxicol Chem 2014;33:592–601. © 2013 SETAC
Cellular uptake of nanoparticles as determined by particle properties, experimental conditions, and cell type
Authors: Kettler Katja , Veltman Karin , van de Meent Dik , van Wezel Annemarie , Hendriks A. Jan 
Published: November 2013

Abstract

The increased application of nanoparticles (NPs) is increasing the risk of their release into the environment. Although many toxicity studies have been conducted, the environmental risk is difficult to estimate, because uptake mechanisms are often not determined in toxicity studies. In the present study, the authors review dominant uptake mechanisms of NPs in cells, as well as the effect of NP properties, experimental conditions, and cell type on NP uptake. Knowledge of NP uptake is crucial for risk assessment and is essential to predict the behavior of NPs based on their physical–chemical properties. Important uptake mechanisms for eukaryotic cells are macropinocytosis, receptor-mediated endocytosis, and phagocytosis in specialized mammalian cells. The studies reviewed demonstrate that uptake into nonphagocytic cells depends strongly on NP size, with an uptake optimum at an NP diameter of approximately 50 nm. Increasing surface charges, either positive or negative, have been shown to increase particle uptake in comparison with uncharged NPs. Another important factor is the degree of (homo-) aggregation. Results regarding shape have been ambiguous. Difficulties in the production of NPs, with 1 property changed at a time, call for a full characterization of NP properties. Only then will it be possible to draw conclusions as to which property affected the uptake. Environ Toxicol Chem 2014;33:481–492. © 2013 SETAC
Electrodeposited Palladium Nanoflowers for Electrocatalytic Applications
Authors: Maniam K. K. , Chetty R. 
Published: November 2013

AbstractPalladium was electrodeposited on an electrochemically activated carbon black substrate using potentiostatic technique, with and without the addition of polyethylene glycol (PEG‐6000) as an additive. Scanning electron micrographs showed change in morphology of Pd from spherical to flower, with increasing additive concentration. As an electrocatalyst for oxygen reduction reaction (ORR), formic acid oxidation and CO stripping, Pd nanoflowers displayed three‐ to fourfold increase in electrocatalytic activity in comparison to the spherical Pd deposits in terms of electrochemical surface area (ESA) and mass specific current density. X‐ray diffraction (XRD) patterns showed, the introduction of additive with varying concentration effect the direction of Pd growth thereby changing the morphology from spherical to flower. The result demonstrates an increase in efficiency of Pd utilization achieved with the addition of PEG during electrodeposition, which could also be applicable to other precious metal electrocatalysts. A scheme for the change in Pd morphology during electrodeposition with additive is also proposed.
Do changes in specific cognitive functions predict changes in health‐related quality of life in people with Alzheimer's disease?
Authors: Bosboom Pascalle R. , Almeida Osvaldo P. 
Published: November 2013

ObjectiveCurrently available pharmacological treatments in Alzheimer's disease (AD) have been associated with modest benefits to cognition, but the impact on health‐related quality of life (HRQoL) is less well established. Our aim was to determine if decline of specific cognitive functions commonly associated with AD predict which patients maintain or experience a deterioration of their HRQoL over 18 months.MethodsWe completed an 18‐month longitudinal study of 47 community‐dwelling older adults diagnosed with probable AD of mild or moderate severity (NINCDS‐ADRD criteria) and their family carers. The primary outcomes of interest were 18‐month change in self‐reported and carer‐reported ratings on the quality of life‐AD (QoL‐AD). The main explanatory variables were 18‐month change in specific cognitive functions using a broad range of established tests. Because of multiple comparisons, alpha was set at 1%.ResultsTwenty six of 47 and 20/47 participants with AD showed evidence of stable or increased QoL‐AD over 18 months according to self report and carer report. Logistic regression analyses showed that for every increase in one standardized score of California Verbal Learning Test‐II short delay free recall the odds of stable/increased self‐rated QoL‐AD over 18 months were 0.27 (95%CI: 0.11, 0.67; p = 0.005). After adjustment for anxiety and depression, this inverse association no longer met the study criteria for statistical significance (adjusted OR: 0.31, 95%CI: 0.11, 0.86; p = 0.025). None of the other standardized changes of cognitive scores were associated with self‐rated or carer‐rated QoL‐AD grouping.ConclusionChanges in specific cognitive functions are not associated with changes in HRQoL ratings in AD. Findings suggest that interventions that limit their focus to improving cognitive functions of people with mild to moderate AD living in the community might fail to have an impact on participants' HRQoL. Copyright © 2013 John Wiley & Sons, Ltd.