bluuebunny/crossref_metadata_2025_split huggingface dataset:
Totalsynthesen der Welwitindolinone mit Bicyclo[4.3.1]‐Kern
Authors: Huters Alexander D. , Styduhar Evan D. , Garg Neil K. 
Published: March 2012

AbstractDie Welwitindolinone mit einem Bicyclo[4.3.1]‐Kern sind eine Klasse von Naturstoffen, die aufgrund ihrer faszinierenden Strukturen und ihrer vielversprechenden biologischen Eigenschaften bei Synthesechemikern großes Interesse hervorgerufen haben. Weltweit haben mehr als fünfzehn Laboratorien Fortschritte bei der Erforschung dieser empfindlichen Naturstoffe gemeldet. Hier werden aktuelle Untersuchungen zur Totalsynthese dieser anspruchsvollen Zielverbindungen dargelegt, und die beiden Synthesen von Welwitindolinonen mit einem Bicyclo[4.3.1]‐Kern, über die Rawal und Garg im Jahr 2011 berichteten, werden besprochen. Die beiden erst kürzlich vollendeten Ansätze beruhen auf der C4‐C11‐Bindungsbildung, wodurch das sterisch überladene bicyclische Gerüst dieser empfindlichen Naturstoffe zugänglich wird.
Relative contribution of small mountain ponds to regional richness of littoral macroinvertebrates and the implications for conservation
Authors: Martínez‐Sanz Carlos , Cenzano Cynthia S. S. , Fernández‐Aláez Margarita , García‐Criado Francisco 
Published: March 2012

ABSTRACT

Biodiversity is a central concept in conservation programme design. Until recently, ponds were neglected habitats probably owing to their small size and to the ignorance of their real conservation value. The classical theory of species‐area relationship (SAR) might apparently support such a view by predicting low richness values in small habitat patches. SAR theory does not take into account the fact that groups of small habitat patches can significantly contribute to regional richness, regardless of their overall small area. This work intends to contribute to the SLOSS (single large or several small) debate with data on littoral macroinvertebrates from mountain ponds. Do groups of small ponds support communities with higher biodiversity than a single large lake?
Littoral macroinvertebrate richness, both local and regional, were measured in 17 ponds and one large lake from Sanabria Natural Park (NW Spain). In order to guarantee valid comparisons among systems, observed and estimated richness, as well as rarefaction methods were used.
Although local richness in the lake was much higher than in any single pond, regional richness of ponds widely exceeded the value measured in the lake regardless of their small overall area. Six to seven ponds were enough to obtain an accumulated average richness equivalent to that in the lake.
This pattern may be caused partly by increased habitat heterogeneity as proposed by the niche theory. Metacommunity theory might help to explain the high regional richness measured in the group of ponds in the study area.
Whatever the explanation, it is evident that groups of mountain ponds strongly contribute to regional richness, a conclusion that should be taken into account by management programmes. There is a gap in this respect in European legislation (the EC Habitats Directive and Water Framework Directive), which fails to include groups of ponds as an additional habitat category. Copyright © 2012 John Wiley & Sons, Ltd.
Vascular Contrast Enhanced Micro‐CT Imaging of “Radiators” in the Brazilian Free‐Tailed Bat (Tadarida brasiliensis)
Authors: Reichard Jonathan D. , Kunz Thomas H. , Keller Charles , Prajapati Suresh I. 
Published: March 2012

AbstractThermal Infrared image of Brazilian free‐tailed bats. See Figure 1A in Reichard et al., on page 564, in this issue.
Charge Matching on Designing Neutral Cadmium–Lanthanide–Organic Open Frameworks for Luminescence Sensing
Authors: Yang Hui , Wang Fei , Tan Yan‐Xi , Kang Yao , Li Tie‐Hu , Zhang Jian 
Published: March 2012

AbstractThrough careful consideration of charge matching, a simple replacement of metal ion from Cd2+ to Ln3+ in a building unit successfully transforms an anionic microporous framework into a series of isostructural porous neutral heterometallic frameworks [Cd3Ln2(btc)4(H2O)6(dmf)4]⋅x(solvent) (1; Ln=Tb, Eu, Nd, Gd, Sm, dmf=N,N′‐dimethylformamide) by employing five different lanthanide ions. 1‐Tb and 1‐Eu exhibit interesting photoluminescent properties, and remarkably, 1‐Tb can act as a luminescent sensor to identify organic solvents and metal ions.
Formal Synthesis of (−)‐Englerin A and Cytotoxicity Studies of Truncated Englerins
Authors: Xu Jing , Caro‐Diaz Eduardo J. E. , Batova Ayse , Sullivan Steven D. E. , Theodorakis Emmanuel A. 
Published: March 2012

AbstractAn efficient formal synthesis of (−)‐englerin A (1) is reported. The target molecule is a recently isolated guaiane sesquiterpene that possesses highly potent and selective activity against renal cancer cell‐lines. Our enantioselective strategy involved the construction of the BC ring system of compound 1 through a RhII‐catalyzed [4+3] cycloaddition reaction followed by subsequent attachment of the A ring through an intramolecular aldol condensation reaction. As such, this strategy allows the synthesis of truncated englerins. Evaluation of these analogues with the A498 renal cancer cell‐line suggested that the A ring of englerin is crucial to its antiproliferative activity. Moreover, evaluation of these analogues led to the identification of potent growth‐inhibitors of CEM cells with GI50 values in the range 1–3 μM.
Image analysis in fluorescence microscopy: Bacterial dynamics as a case study
Authors: van Teeffelen Sven , Shaevitz Joshua W. , Gitai Zemer 
Published: March 2012

AbstractFluorescence microscopy is the primary tool for studying complex processes inside individual living cells. Technical advances in both molecular biology and microscopy have made it possible to image cells from many genetic and environmental backgrounds. These images contain a vast amount of information, which is often hidden behind various sources of noise, convoluted with other information and stochastic in nature. Accessing the desired biological information therefore requires new tools of computational image analysis and modeling. Here, we review some of the recent advances in computational analysis of images obtained from fluorescence microscopy, focusing on bacterial systems. We emphasize techniques that are readily available to molecular and cell biologists but also point out examples where problem‐specific image analyses are necessary. Thus, image analysis is not only a toolkit to be applied to new images but also an integral part of the design and implementation of a microscopy experiment.
Structure and transmembrane topology of slc11a1 TMD1–5 in lipid membranes
Authors: Li Jiantao , Wang Lingling , Wang Li , Li Fei 
Published: March 2012

AbstractThe importance of solute carrier family 11 (Slc11) in divalent metal‐ion transport has been well established. The core domains TMD1–5 and TMD6–10 of the proteins were modeled as a symmetric but inversely orientated arrangement with respect to membrane normal. In this article, the structures and transmembrane topologies of TMD1–5 of Slc11a1 incorporated with phospholipids 1‐palmitoyl‐2‐oleoyl‐ sn‐glycero‐3‐phosphocholine (POPC), 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐[phospho‐rac‐(1‐glycerol)] (sodium salt) (POPG), and POPC/POPG (3:1) were explored using circular dichroism, fluorescence, and attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopies. The segments TMD2–5 were inserted in lipid membranes mainly as an α‐helix with orientations of helices along membrane normal. The tilt angles of the helices were in an order of TMD3 > TMD4 > TMD2 > TMD5 in these membranes. In contrast, TMD1 was partly inserted in membranes, leaving partial segment at membrane surface. The amount of the lipid component with negatively charged headgroups had an effect on both the helicity and orientation of the transmembrane domains (TMDs). Nevertheless, the helices maintained similar topologies in various membranes. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 224–233, 2012.
Evaluation of five risk prediction models for elective abdominal aortic aneurysm repair using the UK National Vascular Database
Authors: Grant S W , Grayson A D , Mitchell D C , McCollum C N 
Published: March 2012

Abstract

Background
There is no consensus on the best risk prediction model for mortality following elective abdominal aortic aneurysm (AAA) repair. The objective was to evaluate the performance of five risk prediction models using the UK National Vascular Database (NVD).

Methods
Data on elective AAA repairs from the NVD between January 2008 and December 2010 were analysed. The models assessed were: Glasgow Aneurysm Score (GAS), Vascular Biochemical and Haematological Outcome Model (VBHOM), physiological component of the Vascular Physiological and Operative Severity Score for enUmeration of Mortality (V-POSSUM), Medicare and Vascular Governance North West (VGNW). Overall model discrimination and calibration in equally sized risk-group quintiles were assessed.

Results
The study cohort included 10 891 patients undergoing elective AAA repair (median age 74 years, 87·3 per cent men). The in-hospital mortality rates following endovascular and open repair were 1·3 and 4·7 per cent respectively (2·9 per cent overall). The Medicare and VGNW models both showed good discrimination (area under receiver operating characteristic (ROC) curve 0·71), whereas the GAS, VBHOM and V-POSSUM models showed poor discrimination (area under ROC curve 0·60, 0·61 and 0·62 respectively). The VGNW model was the only one to predict the overall mortality rate in the cohort (3·3 per cent predicted versus 2·9 per cent observed; P = 0·066). The VGNW model demonstrated good calibration, predicting risk accurately in four risk-group quintiles. The Medicare, V-POSSUM and VBHOM models accurately predicted risk in three, two and no risk-group quintiles respectively.

Conclusion
The Medicare and VGNW models contain similar risk factors and showed good discrimination when applied to the NVD. Both models would be suitable for risk prediction after elective AAA repair in the UK.
Effect of Temperature in Hydrocracking of Light Cycle Oil on a Noble Metal‐Supported Catalyst for Fuel Production
Authors: Gutiérrez A. , Arandes J. M. , Castaño P. , Olazar M. , Barona A. , Bilbao J. 
Published: March 2012

AbstractThe effect of temperature has been studied in hydrocracking of light cycle oil (LCO), byproduct of fluidized catalytic cracking (FCC) units on a bifunctional catalyst (Pt‐Pd/HY zeolite). The increase in both temperature and H2 partial pressure have an important attenuating effect on catalyst deactivation, given that they decrease sulfur equilibrium adsorption and enhance hydrocracking of coke precursors. Therefore, the catalyst maintains significant hydrodesulfurization and hydrocracking activity. As the temperature is increased, hydrocracking conversion and naphtha selectivity increase, although there is no significant dearomatization of the medium distillate fraction in the range of the studied experimental conditions. 400 °C is the more suitable temperature for obtaining a high yield of naphtha with a high content of i‐paraffins.
Single‐Jet Precipitation of Silver Nanocrystals in the Presence of Poly(acrylic) Acid
Authors: Mikami T. , Nagahori T. , Saito J. , Hirasawa I. 
Published: March 2012

AbstractPrecipitation of silver nanocrystals was carried out in a poly(acrylic) acid (PAA) solution by using a single‐jet crystallizer. The influence of the feeding rate, the injection position and the PAA dosage on the crystal size distribution (CSD) was clarified. The precipitated silver nanocrystals agglomerate with each other, forming an agglomerated microcrystal. In the presented case, smaller feeding rates caused smaller crystal sizes and narrower CSD widths. PAA, which is a water‐soluble polyelectrolyte, successfully inhibited agglomeration and crystal growth, and decreased the crystal size and the CSD width. Thus, this idea may also facilitate the production of other nano‐/microcrystalline particles.
Filter Cake Washing of Mesoporous Particles
Authors: Noerpel S. , Siauw V. , Nirschl H. 
Published: March 2012

AbstractParticle synthesis in liquid phase usually requires a subsequent washing step in order to remove undesirable impurities such as unreacted educts, byproducts, solvents and salts. In particular, the washing of mesoporous particles is a challenging task due to large specific surface areas and void volumes. The filter cake washing of mesoporous SiO2 particles contaminated either with an adsorbing fluorescent dye or sodium sulfate is presented. The effects of wash liquid mass flow rate, mean particle size, and mean pore size on the wash efficiency were investigated. Especially the interaction between impurities and the solid surface, and thereby the initial impurity distribution within the filter cake, led to distinctive washing behaviors.
Mesoporous Au/TiO2 Nanocomposite Microspheres for Visible‐Light Photocatalysis
Authors: Wang Guannan , Wang Xiaofei , Liu Junfeng , Sun Xiaoming 
Published: March 2012

AbstractMesoporous Au/TiO2 nanocomposite microspheres have been synthesized by using a microemulsion‐based bottom‐up self‐assembly (EBS) process starting from monodisperse gold and titania nanocrystals as building blocks. The microspheres had large surface areas (above 270 m2 g−1) and open mesopores (about 5 nm), which led to the adsorption‐driven concentration of organic molecules in the vicinity of the microspheres. Au nanoparticles, which were stably confined within the microspheres, enhanced the absorption over the broad UV/Vis/NIR spectroscopic range, owing to their strong surface plasmon resonance (SPR); as a result, the Au nanoparticles promoted the visible‐light photo‐induced degradation of organic compounds.
Synthesis of a Hierarchical Three‐Component Nanocomposite Structure System with Enhanced Electrocatalytic and Photoelectrical Properties
Authors: Zhao Zhenlu , Zhang Guo , Sun Lei , Gao Ying , Yang Xiuyun , Li Yunhui 
Published: March 2012

AbstractEffective control over the morphology and size of Pd/Pt nanoparticles is currently of immense interest because their electronic, optical, and catalytic properties are superior to pure platinum nanoparticles. However, control over the nanoparticle shape is still challenging. Therefore, a novel design and synthetic route needs to be developed to obtain a high‐performance catalyst. Herein, a hierarchical three‐component nanocomposite structure system (HTNSS) composed of graphene, TiO2, and Pd@Pt core–shell nanoparticles was designed and synthesized by a sequential strategy that focuses on constructing the monolithic structure rather than limited single‐component counterparts. The resulting composites were characterized by various techniques, which showed that the Pd@Pt core–shell nanoparticles were preferentially deposited on the peripheral interface of the graphene and TiO2 nanoparticles. The photoelectrical and catalytic performances were obviously improved relative to the commercially available E‐TEK Pt/C owing to their synergistic effect.
Oligonuclear Molecular Models of Intermetallic Phases: A Case Study on [Pd2Zn6Ga2(Cp*)5(CH3)3]
Authors: Bollermann Timo , Molon Mariusz , Gemel Christian , Freitag Kerstin , Seidel Rüdiger W. , von Hopffgarten Moritz , Jerabek Paul , Frenking Gernot , Fischer Roland A. 
Published: March 2012

AbstractThe synthesis, characterization, and theoretical investigation by means of quantum‐chemical calculations of an oligonuclear metal‐rich compound are presented. The reaction of homoleptic dinuclear palladium compound [Pd2(μ‐GaCp*)3(GaCp*)2] with ZnMe2 resulted in the formation of unprecedented ternary Pd/Ga/Zn compound [Pd2Zn6Ga2(Cp*)5(CH3)3] (1), which was analyzed by 1H and 13C NMR spectroscopy, MS, elemental analysis, and single‐crystal X‐ray diffraction. Compound 1 consisted of two Cs‐symmetric molecular isomers, as revealed by NMR spectroscopy, at which distinct site‐preferences related to the Ga and Zn positions were observed by quantum‐chemical calculations. Structural characterization of compound 1 showed significantly different coordination environments for both palladium centers. Whilst one Pd atom sat in the central of a bi‐capped trigonal prism, thereby resulting in a formal 18‐valence electron fragment, {Pd(ZnMe)2(ZnCp*)4(GaMe)}, the other Pd atom occupied one capping unit, thereby resulting in a highly unsaturated 12‐valence electron fragment, {Pd(GaCp*)}. The bonding situation, as determined by atoms‐in‐molecules analysis (AIM), NBO partial charges, and molecular orbital (MO) analysis, pointed out that significant PdPd interactions had a large stake in the stabilization of this unusual molecule. The characterization and quantum‐chemical calculations of compound 1 revealed distinct similarities to related M/Zn/Ga Hume–Rothery intermetallic solid‐state compounds, such as Ga/Zn‐exchange reactions, the site‐preferences of the Zn/Ga positions, and direct MM bonding, which contributes to the overall stability of the metal‐rich compound.
Branched Mesoporous Mn3O4 Nanorods: Facile Synthesis and Catalysis in the Degradation of Methylene Blue
Authors: Bai Zhongchao , Sun Bo , Fan Na , Ju Zhicheng , Li Menghua , Xu Liqiang , Qian Yitai 
Published: March 2012

AbstractBranched MnOOH nanorods with diameters in the range of 50–150 nm and lengths of up to tens of micrometers were prepared by using potassium permanganate (KMnO4) and PEG 400 (PEG=polyethylene glycol) as starting materials through a simple hydrothermal process at 160 °C. After annealing at 300 °C under a N2 atmosphere for 5 h, MnOOH nanorods became gradually dehydrated and transformed into mesoporous Mn3O4 nanorods with a slight size‐shrinking. The as‐obtained mesoporous Mn3O4 nanorods had an average surface area of 32.88 m2 g−1 and a mean pore size of 3.7 nm. Through tuning the experimental parameters, such as the annealing atmosphere and temperature, β‐MnO2, Mn2O3, Mn3O4, MnO, and Mn5O8 were selectively produced. Among these structures, mesoporous Mn3O4 nanorods were efficient for the catalytic degradation of methylene blue (MB) in the presence of H2O2 at 80 °C.
Scandium(III)‐Zeolites as New Heterogeneous Catalysts for Imino‐Diels–Alder Reactions
Authors: Olmos Andrea , Louis Benoit , Pale Patrick 
Published: March 2012

AbstractThis study demonstrates the first zeolite‐catalyzed synthesis of piperidine derivatives, including peptidomimetics and indoloquinolizidine alkaloids. The approach developed utilizes a highly effective one‐pot reaction cascade, through imine formation and imino‐Diels–Alder reactions, promoted by scandium‐loaded zeolites as a heterogeneous catalyst. The methodology described benefits from very low catalyst loadings (≤5 mol % of ScIII), commercially and readily available starting materials, and mild reaction conditions. Furthermore, the ScIII‐zeolite catalyst can be readily reused more than 10 times without any loss in efficiency.
Characterisation of Solute Mobility in Hypercross‐Linked Resins in Solvents of Different Polarity: Two Promising Supports for Catalysis
Authors: Bortolus Marco , Centomo Paolo , Zecca Marco , Sassi Alessandro , Jeřábek Karel , Maniero Anna Lisa , Corain Benedetto 
Published: March 2012

AbstractTwo hypercross‐linked resins stemming from a gel‐type poly‐chloromethylated styrene‐divinylbenzene resin (GT) in beaded form are investigated with a combination of spectroscopic techniques (EPR and time‐domain (TD)‐NMR spectroscopy) to evaluate their use as supports for the development of operationally flexible heterogeneous metal catalysts, suitable to be employed in liquid and gas phase. The first resin (HGT) is the direct product of the hypercross‐linking reaction, whereas the second one (HGS) is the sulphonated analogue of HGT obtained by exchanging approximately 3 wt % of the chloromethyl groups with sulphonic groups. HGT and HGS absorb both polar and apolar solvents in the permanent nanoporosity created by the hypercross‐linking, and NMR data highlight that the pore size is not affected by the different properties of the investigated liquid media. The EPR analysis of the dry resins reveals that during the hypercross‐linking process paramagnetic species are formed in the HGT beads, which persist in the sulphonated resin. The mobility of solutes inside the polymers framework was investigated with EPR spectroscopy upon soaking the resins with solutions of two spin probes (2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) and 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPOL)) in THF, toluene, n‐heptane and water. The EPR spectra show that, depending on the solvent, the two resins can act as sorbents, able to trap the solutes in the polymer framework, or as simple supports that allow free diffusion of the solutes. Our results suggest that HGT and HGS are promising supporting materials for metal catalysts, provided one chooses carefully the solvent to be employed for the catalysed reaction as this choice strongly affects the mobility of the substrates and, thus their effective reactivity.
Congruence of primary brain tumor patient and caregiver symptom report
Authors: Armstrong Terri S. , Wefel Jeffrey S. , Gning Ibrahima , Acquaye Alvina , Vera‐Bolanos Elizabeth , Gilbert Mark R. , Cleeland Charles S. , Mendoza Tito 
Published: March 2012

AbstractBACKGROUND:Evaluating the severity of symptoms in patients with primary brain tumors (PBTs) is important in clinical care and research but may be difficult due to patient neurocognitive (NC) impairment. This study was conducted to evaluate the congruence of symptom reporting in patient and caregiver dyads, examining potential impact of NC impairment and Karnofsky performance status (KPS).METHODS:PBT patients undergoing NC testing and their caregivers were included in this study. These dyads (paired patient and caregiver group) completed the MD Anderson Symptom Inventory‐Brain Tumor Module prior to testing, and impairment was categorized based on NC test scores. Concordance and equivalency was then assessed using Bland‐Altman analysis and 2 one‐sided techniques.RESULTS:A total of 115 dyads participated. Median patient and caregiver age was 49 and 51 years, respectively, and 63% of patients were male (73% female caregivers). Most patients had a good KPS (≥90, 66%) but were classified as NC impaired (58%). Caregiver's report of patient symptoms are congruent to the self‐report of the patient. Equivalency between patient and caregiver report were found using prespecified confidence intervals. KPS group (good, ≥90; poor, ≤80) comparisons of equivalency indicated no significant differences in symptoms and interference reporting between dyads (good = 0.49, P > .05; and poor = 0.3, P > .05) overall, but there was a tendency for higher report by caregivers if the patients had a poor KPS.CONCLUSIONS:Caregivers of PBT patients have similar assessments of symptom severity (highly congruent) with patient self‐report regardless of NC function or KPS. These findings suggest that caregivers may serve as proxy report of symptoms for primary brain tumor patients. Cancer 2012. © 2012 American Cancer Society.