bluuebunny/crossref_metadata_2025_split huggingface dataset:
Migrating components in a polyurethane laminating adhesive identified using gas chromatography/mass spectrometry
Authors: Athenstädt Behnusch , Fünfrocken Michael , Schmidt Torsten C. 
Published: July 2012

RATIONALEPlastics are increasingly used as packaging materials for pharmaceuticals. However, diffusion of compounds in plastic into drugs may endanger patients' health. Regulatory authorities therefore demand detailed information about leachable compounds in plastics. Here we identify migrating components of a sterilization‐resistant polyurethane (PUR) adhesive used in the primary packaging for an aqueous pharmaceutical. This identification is an essential first step for quantification and toxicological evaluation of the compounds.METHODSWe used various hyphenated mass spectrometry (MS) methods: gas chromatography (GC/MS) with either electron impact ionization or chemical ionization, and high resolution liquid chromatography (LC/MS) with electrospray ionization.RESULTSOf the 13 migrating substances detected, 11 are cyclic esters with characteristic fragmentation schemes apparent from their mass spectra. These esters are formed as by‐products during the reaction of adipic and isophthalic acid with monoethylene glycol and diethyelene glycol. A cyclic ester of isophthalic acid and tetraethylene glycol and a product of the reaction of isophoron diisocyanate with methanol were clearly identified.CONCLUSIONSComplementary use of several hyphenated mass spectrometric methods enables successful identification of leachable compounds in the PUR adhesive under study. This opens the way for quantification and evaluation of the potential toxicities of these compounds. Despite the range of compositions of PUR laminates, the approach presented here may be applicable for the qualitative assessment of all PURs. Copyright © 2012 John Wiley & Sons, Ltd.
Investigation of non‐covalent interaction of natural flexible cyclic molecules with telomeric RNA G‐quadruplexes by electrospray ionization mass spectrometry
Authors: Cui Xiaojie , Lin Sen , Zhou Jiang , Yuan Gu 
Published: July 2012

RATIONALERecently, human telomeric DNA was found to be transcribed into RNA transcripts composing of tandem repeats of r(UUAGGG) which can form G‐quadruplex structures. Studies have shown that human telomeric RNA is associated with the telomerase activity in vitro. Finding high affinity small molecule ligands binding to the telomeric RNA G‐quadruplex may facilitate the regulation of the telomerase activity.METHODSThe 12‐mer and 24‐mer telomeric RNA sequences, r(UAGGGUUAGGGU) and r(UAGGGUUAGGGUUAGGGUUAGGGU), were synthesized by TaKaRa Biotechnology (Dalian) Co., Ltd. (TaKaRa, Dalian) with high‐performance liquid chromatography (HPLC) purification. Electrospray ionization ion‐trap mass spectrometry was used to evaluate the binding affinities of three natural flexible cyclic molecules, tetrandrine, fangchinoline and cepharanthine, with the telomeric RNA G‐quadruplexes. The fragmentation pathways of the G‐quadruplexes and G‐quadruplex‐ligand complexes were investigated by tandem mass spectrometry.RESULTSthe natural flexible cyclic molecules were found to have high binding affinities to the 12‐mer and 24‐mer RNA G‐quadruplexes with stoichiometry of 1:1 to 3:1. Collision‐induced dissociation tandem mass spectrometry shows that the G‐quadruplex‐ligand complexes lose neutral ammoniums first and the small molecule ligand subsequently. Besides, among the three flexible cyclic molecules, cepharanthine binds most tightly to the RNA G‐quadruplexes than tetandrine and fangchinoline.CONCLUSIONSThree flexible cyclic small molecules were found to be potential telomeric RNA G‐quadruplex ligands, especially cepharanthine, which has high affinity and binds most tightly to the RNA G‐quadruplexes. These findings may provide further implications in the regulation of telomeric RNA and telomerase activity. Copyright © 2012 John Wiley & Sons, Ltd.
Etching of polyethylene terephthalate thin films by neutral oxygen atoms in the late flowing afterglow of oxygen plasma
Authors: Vesel Alenka , Kolar Metod , Doliska Ales , Stana‐Kleinschek Karin , Mozetic Miran 
Published: July 2012

ABSTRACTFilms of polyethylene terephthalate were deposited on quartz crystals and exposed to oxygen atoms to study their etching characteristics and quantify the etching rate. Oxygen (O) atoms were created by passing molecular oxygen through plasma created in a microwave discharge. The discharge power was fixed at 250 W, while the pressure of oxygen was 50 Pa. Before exposure to oxygen atoms, a thin polymer film of polyethylene terephthalate (PET) was deposited uniformly over a crystal with a diameter of 12 mm. The crystal was mounted on a quartz crystal microbalance to accurately determine the thickness of the polymer film. The polymer film was exposed to O atoms in the flowing afterglow. The density of O atoms was measured with a cobalt catalytic probe mounted next to the sample and was determined to be 1.2 × 1021 m–3. Samples were treated with O atoms for different periods of up to 120 min. The thickness of the film decreased linearly with treatment time. After 90 min of treatment, a 65‐nm‐thick polymer film was completely removed. Therefore, the etching rate was 0.5 nm/min, so the interaction probability between an O atom and an atom in the sample was extremely low, just 1.4 × 10–6. Samples treated for different periods were investigated by atomic force microscopy and X‐ray photoelectron spectroscopy to examine the etching characteristics of O atoms in the flowing afterglow. Copyright © 2012 John Wiley & Sons, Ltd.
Direct Visualization of Symmetry Breaking During Janus Nanoparticle Formation
Authors: Loget Gabriel , Lee Tung C. , Taylor Richard W. , Mahajan Sumeet , Nicoletti Olivia , Jones Samuel T. , Coulston Richard J. , Lapeyre Véronique , Garrigue Patrick , Midgley Paul A. , Scherman Oren A. , Baumberg Jeremy J. , Kuhn Alexander 
Published: July 2012

AbstractThe straight‐forward synthesis of Janus nanoparticles composed of Ag and AgBr is reported. For their formation, cucurbit[n]uril (CB)‐stabilized AgBr nanoparticles are first generated in water by precipitation. Subsequent irradiation with an electron beam transforms a fraction of each AgBr nanoparticle into Ag0, leading to well‐defined Janus particles, stabilized by the binding of CB to the surface of both AgBr and Ag0. With the silver ion reduction being triggered by the electron beam, the progress of the transformation can be directly monitored with a transmission electron microscope.
Nanolattices of Switchable DNA‐Based Motors
Authors: Saccà Barbara , Siebers Benjamin , Meyer Rebecca , Bayer Manfred , Niemeyer Christof M. 
Published: July 2012

AbstractMiniaturization is an important aspect of device fabrication. Despite the advancements of modern top‐down approaches, scaling‐down to the sub‐nanometer size is still a challenge. As an alternative, bottom‐up approaches, such as the use of DNA as an engineering material, are therefore emerging, allowing control of matter at the single‐molecule level. A DNA‐based self‐assembly method for the construction of switchable DNA devices is descrbied here based on G‐quadruplex moieties, which are patterned on quasi‐planar DNA arrays with nanoscale precision. The reversible switching of the devices is triggered by addition of DNA sequences (‘fuels’) and translated into linear extension/contractile movements. The conformational change of the devices was visualized by atomic force microscopy and FRET spectroscopy. Steady state fluorescence spectroscopy indicated that scaffolding of the G4 motors to either individual tiles or extended superlattices had no significant impact on the switching and optical performance of the system. However, time‐resolved spectroscopy revealed that ordering in the microstructural environment enhances the fraction of molecules subject to FRET. Altogether, our study confirms that DNA superstructures are well‐suited scaffolds for accommodation of mechanically switchable units and thus opens the door to the development of more sophisticated nanomechanical devices.
Plasmonic Nanogap‐Enhanced Raman Scattering Using a Resonant Nanodome Array
Authors: Wu Hsin‐Yu , Choi Charles J. , Cunningham Brian T. 
Published: July 2012

AbstractThe optical properties and surface‐enhanced Raman scattering (SERS) of plasmonic nanodome array (PNA) substrates in air and aqueous solution are investigated. PNA substrates are inexpensively and uniformly fabricated with a hot spot density of 6.25 × 106 mm−2 using a large‐area nanoreplica moulding technique on a flexible plastic substrate. Both experimental measurement and numerical simulation results show that PNAs exhibit a radiative localized surface plasmon resonance (LSPR) due to dipolar coupling between neighboring nanodomes and a non‐radiative surface plasmon resonance (SPR) resulting from the periodic array structure. The high spatial localization of electromagnetic field within the ∼10 nm nanogap together with the spectral alignment between the LSPR and excited and scattered light results in a reliable and reproducible spatially averaged SERS enhancement factor (EF) of 8.51 × 107 for Au‐coated PNAs. The SERS enhancement is sufficient for a wide variety of biological and chemical sensing applications, including detection of common metabolites at physiologically relevant concentrations.
A Review of the Relationship between Viscosity and the Structure of Calcium‐Silicate‐Based Slags in Ironmaking
Authors: Sohn Il , Min Dong Joon 
Published: July 2012

AbstractThis review focuses on elucidating the viscosity of ironmaking slags and the effect of various components in the multi‐component calcium‐silicate‐based slag system on the viscosity. Using various widely used spectroscopic techniques including Fourier transform infrared (FTIR), Raman, X‐ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR), the viscous behavior and the slag structure of this system were correlated. In particular, the review begins with an introduction to the viscous behavior of binary silicate systems and an identification of the intricate details of the slag structure. Using the binary system as a basis, the compounded effect of typical ironmaking slag components such as Al2O3, MgO, alkali oxides, and TiO2 on the viscosity is introduced through expansion to a quinary slag system. Using a combination of the aforementioned spectroscopic methods, the meticulous details of the slag structure were ascertained, and the depolymerization or polymerization mechanisms of the silicate and alumino‐silicate structures were subsequently identified. This review also compares well‐known viscosity prediction models with experimentally measured values and identifies potential fields of research in the ironmaking industry associated with slag viscosities.
A Bayesian model for inference on population proportions
Authors: Okafor R. O. , Mbata U. A. 
Published: July 2012

AbstractIn recent times and even up to now, traffic congestion and parking difficulties, especially during morning and evening rush hours, have become a major concern to members of the University of Lagos (UNILAG) community and visitors alike. UNILAG has witnessed unprecedented growth in student enrollment during the past 10 years or so culminating in the current total enrollment of more than 35,000 students, of which about 25,000 are undergraduates. In order to study the worrisome traffic situation at UNILAG in the wake of these large numbers, independent, although similar, sample surveys of undergraduate students of the eight faculties on the main campus of UNILAG were conducted in 2007. The purpose of the surveys was to collect data on undergraduate students who owned or used motor vehicles on campus. Furthermore, to investigate possible temporal trends, the surveys were repeated in 2009. The types of data obtained from the surveys provided veritable impetus for the application of empirical Bayes (EB) analysis to estimate the proportions of students of individual faculties who used motor vehicles on campus roads during the periods under reference. The EB technique, being a Bayesian method, combines prior information and sample information in a manner that ‘shrinks’ an EB estimator toward the sample estimator if a vague prior (proper prior with a large variance) is used. The main result is that in 2007 about one in four students used motor vehicles, and this result held almost across the eight faculties. Although results of the 2009 surveys were generally similar there were faculties that recorded some reduction in the estimated proportions of students who used motor vehicles. WIREs Comput Stat 2012 doi: 10.1002/wics.1218This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Bayesian Methods and Theory
Smart polymersomes for therapy and diagnosis: fast progress toward multifunctional biomimetic nanomedicines
Authors: De Oliveira Hugo , Thevenot Julie , Lecommandoux Sébastien 
Published: July 2012

AbstractRising from the shortcomings of modern day therapeutics there is a need for a controlled approach in carrier‐mediated drug delivery. Polymeric vesicles, also called polymersomes, are powerful tools to address issues of efficacy, specificity, and controlled release of drugs to diseased tissues. These recent, biomimetic structures are able to overcome the body's natural defences, remaining stable for extended time in circulation, have tuneable membrane properties, allowing the control of membrane permeability and therefore of drug release, and have the potential to be functionalized for active targeting of specific tissues, reducing undesirable side effects. Extensive work has been carried out in order to attain multifunctional polymeric vesicles that respond to precise triggers (e.g., temperature, pH, redox, magnetic field, etc) with a spatial and temporal monitoring what may enable unprecedented control of drug release in the body. These versatile structures can be loaded with different type of (bio)molecules and nanoparticles, from drugs to contrast agents for medical imaging, and are able to accommodate them in different subcompartments of the vesicle (i.e., hydrophobic membrane and hydrophilic core). Multimodal targeted delivery system could be obtained from this unique platform, with abilities in both drug delivery and medical imaging contrast enhancement, widening the perspectives toward theranostics. Polymersomes offer a promising route toward more effective treatments with fewer side effects and superior outcomes. WIREs Nanomed Nanobiotechnol 2012, 4:525–546. doi: 10.1002/wnan.1183This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies
Diagnostic Tools > In Vivo Nanodiagnostics and Imaging
Biology-Inspired Nanomaterials > Peptide-Based Structures
Schizosaccharomyces pombe reporter strains for relative quantitative assessment of heterochromatin silencing
Authors: Shimada Yukiko , Bühler Marc 
Published: July 2012

AbstractThe fission yeast Schizosaccharomyces pombe has been emerging as an important model organism for studying the formation and repression of heterochromatin. To enable simple and relative quantitative assessment of heterochromatin silencing, we have created bioluminescence‐based reporter strains. A green‐emitting click beetle luciferase (CBG68) gene was inserted within pericentromeric heterochromatin or at the silent mating‐type locus via homologous recombination. In the same strains, a red‐emitting click beetle luciferase (CBR) gene is expressed from the euchromatic leu1+ locus and can be used as a reference in dual‐colour assays. Our reporter strains are suitable for performing Chroma‐Glo™ assays, which can be carried out directly in the culture medium without prior cell lysis and in a multiwell format. Our reporter system reliably reflects the state of chromatin and can be easily adapted for use in high‐throughput screening approaches. Copyright © 2012 John Wiley & Sons, Ltd.
Lovastatin‐induced apoptosis is modulated by geranylgeraniol in a neuroblastoma cell line
Authors: Marcuzzi Annalisa , Zanin Valentina , Piscianz Elisa , Tricarico Paola Maura , Vuch Josef , Girardelli Martina , Monasta Lorenzo , Bianco Anna Monica , Crovella Sergio 
Published: July 2012

AbstractMevalonic aciduria (MA), the most severe form of mevalonate kinase deficiency (MKD), is still an orphan drug disease and the pathogenetic mechanisms underlying neuronal dysfunction is still poorly understood. In our study we have investigated the apoptotic mechanism mediated by the exposure of the cultured neuroblastoma cell line, SH‐SY5Y, to lovastatin in absence or in presence of the isoprenoid, geranylgeraniol, with the aim of unraveling the pathogenesis of MA. Lovastatin, blocks the mevalonate pathway inhibiting the 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMG‐CR), an enzyme of the mevalonate pathway upstream the mevalonate kinase enzyme, reproducing biochemical features similar to those found in MKD.We demonstrate that apoptosis in neuronal lovastatin treated‐cells is induced by the mitochondrial pathway, with caspase‐9 as the initiator and caspase‐3 as the effector caspase. The presence of geranylgeraniol modulates both the caspase‐9 and caspase‐3 activity in a dose‐dependent way, confirming that this isoprenoid enters the mevalonate pathway, is metabolized and finally is able to by‐pass the statin biochemical block reconstituting the mevalonate pathway. According to our findings, it should not be the time course adopted that modulates the apoptotic response but rather the isoprenoid itself.Being aware that our results have been obtained using a biochemical model of MKD, and not cells from patients with the disease, we believe our findings increase the knowledge of MA pathogenesis, and may possibly contribute to the development of novel therapeutic strategies.
An investigation of PreMCI: Subtypes and longitudinal outcomes
Authors: Loewenstein David A. , Greig Maria T. , Schinka John A. , Barker Warren , Shen Qian , Potter Elizabeth , Raj Ashok , Brooks Larry , Varon Daniel , Schoenberg Michael , Banko Jessica , Potter Huntington , Duara Ranjan 
Published: July 2012

AbstractBackground/AimsTo investigate the clinical features and rates of progression of conditions that are not considered to be normal, but do not fulfill criteria for mild cognitive impairment (MCI).MethodsWe longitudinally evaluated 269 elderly subjects who did not meet formal criteria for MCI at baseline but had: (1) a clinical history suggesting MCI without neuropsychological deficits (PreMCI‐Clinical); or (2) neuropsychological deficits on one or more memory measures in conjunction with a negative clinical examination (amnestic PreMCI‐NP) or were normal on both neuropsychological and clinical examination.ResultsThe rate of progression to MCI or dementia over an average of 2‐ to 3 years was 3.7% for no cognitive impairment subjects, whereas it was significantly greater for all PreMCI subtypes (22.0% for PreMCI‐Clinical, 38.9% for amnestic PreMCI‐NP subjects with two or more memory impairments). Among PreMCI subjects as a whole, lower baseline scores on object memory and category fluency tests were the best predictors of progression to MCI or dementia. Cardiovascular risk factors, Parkinsonian symptoms, and hippocampal atrophy were not associated with progression.ConclusionDistinct PreMCI subtypes defined on the basis of clinical and neuropsychological evaluations were found to have distinct characteristics, but both subtypes demonstrated elevated risk for progression to MCI or dementia. Despite the lack of evidence of clinical impairment, subjects with neuropsychological deficits in two memory domains were particularly at increased risk for progression of their deficits.
Nonsteroidal anti‐inflammatory drug use and the risk of cognitive impairment and Alzheimer's disease
Authors: Côté Sharlène , Carmichael Pierre‐Hugues , Verreault René , Lindsay Joan , Lefebvre Jean , Laurin Danielle 
Published: July 2012

AbstractBackgroundSome observational studies have established an association between exposure to nonsteroidal anti‐inflammatory drugs (NSAIDs) and a decreased risk of subsequently developing Alzheimer's disease (AD). Mild cognitive impairment or cognitive impairment, not dementia (CIND) is more likely to convert to AD, and no specific preventive method is currently available. The objective of this study was to determine the association of NSAID use in 5276 cognitively normal subjects of the Canadian Study of Health and Aging, a 10‐year population‐based cohort study, with the incidence of CIND, AD, and all‐cause dementia.MethodsHazard ratios were calculated from Cox proportional hazards models with age as the time scale according to three study samples including 824 cases of dementia (563 cases of AD), 630 cases of dementia (435 cases of AD), and 883 cases of CIND, respectively. Adjustments were made for gender, education, lifestyle factors, comorbid diseases, and vascular risk factors.ResultsLower risks for AD and all‐cause dementia were significantly associated with the use of any NSAIDs and the salicylates without barbiturates subgroup in the study sample including subjects with CIND at baseline. There was a weak association between any NSAIDs and the risk of CIND (hazard ratio, 0.87; 95% confidence interval, 0.76–1.00).ConclusionThese results suggest that there is an association between NSAID use and a lower incidence of AD and, to a lesser extent, of CIND.
Risk of dementia in an elderly population of Parkinson's disease patients: A 15‐year population‐based study
Authors: Perez Florian , Helmer Catherine , Foubert‐Samier Alexandra , Auriacombe Sophie , Dartigues Jean‐François , Tison François 
Published: July 2012

AbstractBackgroundThe incidence of dementia in Parkinson's disease (PD) is not fully known, and previous studies have provided a wide range of rates owing to variations in diagnostic criteria and methodologies used. We estimated the risk of dementia in newly diagnosed cases of PD in a population‐based cohort of subjects aged >65 years.MethodsWe performed repetitive systematic screening of PD diagnosis, cognitive performances, and clinical dementia during 15 years (at year 0, 3, 5, 8, 10, and 15) in 3726 elderly subjects living at home in southwestern France (PAQUID). Two sets of diagnostic criteria for dementia in PD were considered: Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria and Movement Disorders Society criteria.ResultsForty‐four incident cases of PD occurred in the cohort; of these, 18 (41%) developed dementia during a mean follow‐up of 6.8 ± 3.6 years. Incidence rate of dementia associated with PD was 74 per 1000 patient‐years. The cumulative risk of dementia was approximately 25% and 50% after 5 and 10 years of follow‐up, respectively. The relative risk for developing dementia in incident PD subjects compared with non‐PD subjects was 2.47 (1.55–3.95). Equivalent estimations were obtained with Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria or Movement Disorders Society criteria.ConclusionPD represents a high‐risk stage for dementia in the general population.