bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aqueous synthesis and characterization of nearly monodispersed ZnS nanocrystals
Authors: Azizian‐Kalandaragh Yashar , Khodayari Ali 
Published: May 2010

AbstractAn ultrasound‐assisted solution‐phase process has been applied for the aqueous synthesis of zinc sulfide nanocrystals in the presence of 3‐mercaptopropionic acid (3‐MPA) as a capping agent. The synthesis procedure was carried out by using two reagents: zinc chloride and sodium sulfide. Spherical shaped nanoparticles were agglomerated in the form of nanoclusters were observed. Obtained crystalline materials were found without the need of a post‐synthesis treatment. The preparative conditions such as precursor concentrations, pH, and washing materials were optimized. The average crystalline size of ZnS nanostructures has been analyzed by X‐ray diffraction (XRD) pattern and estimated to be 4.7 nm. The energy dispersive X‐ray analysis (EDAX) reveals the average atomic percentage of Zn/S was 50:50, showing that the preparation is exactly stoichiometric. Optical measurements indicate a direct band gap of about 4.27 eV. There was observed a blue shift of about 0.57 eV, in comparison to its bulk value due to quantum confinement effects of electrons and holes.
(In)AlGaN deep ultraviolet light emitting diodes with optimized quantum well width
Authors: Kolbe Tim , Sembdner Toni , Knauer Arne , Kueller Viola , Rodriguez Hernan , Einfeldt Sven , Vogt Patrick , Weyers Markus , Kneissl Michael 
Published: May 2010

AbstractThe effect of the quantum well (QW) width on the light output and efficiency of ultraviolet (UV) light emitting diodes (LEDs) has been investigated. The carrier injection in the devices is simulated and compared with electroluminescence (EL) measurements. The light output power depends clearly on the QW thickness. The highest output power has been found for the LEDs with a QW thickness of 2.2 nm. This effect is attributed to the trade‐off between electron and hole wave function overlap and carrier concentration in the active region which are triggered by the quantum confined Stark effect.
Direct analysis of pharmaceutical tablet formulations using matrix‐assisted laser desorption/ionisation mass spectrometry imaging
Authors: Earnshaw Caroline J. , Carolan Vikki A. , Richards Don S. , Clench Malcolm R. 
Published: May 2010

AbstractMatrix‐Assisted Laser Desorption/Ionisation Mass Spectrometry Imaging (MALDI MSI) has been used to directly analyse a range of tablets in order to assess the homogeneity of the active drug compound throughout the excipients contained within the tablets studied. The information gained from the imaging experiments can be used to improve and gain a greater understanding of the manufacturing process; such knowledge will enable improvements in finished product quality to make safer and more efficacious tablet formulations. Commercially available and prescription tablet formulations have been analysed, including aspirin, paracetamol, sildenafil citrate (Viagra®) and a batch of tablets in development (tablet X: placebo; 1 mg; 3 mg and 6 mg). MALDI MSI provides semi‐quantitative information that is related to ion abundance, therefore Principal Component Analysis (PCA), a multivariate analysis technique, has been used to differentiate between tablets containing different amounts of active drug ingredient. Aspects of sample preparation have also been investigated with regard to tablet shape and texture. The results obtained indicate that MALDI MSI can be used effectively to analyse the spatial distribution of the active pharmaceutical component (API) in pharmaceutical tablet formulations. Copyright © 2010 John Wiley & Sons, Ltd.
δ13C and δ2H isotope ratios in amphetamine synthesized from benzaldehyde and nitroethane
Authors: Collins Michael , Salouros Helen , Cawley Adam T. , Robertson James , Heagney Aaron C. , Arenas‐Queralt Andrea 
Published: May 2010

AbstractPrevious work in these laboratories and by Butzenlechner et al. and Culp et al. has demonstrated that the δ2H isotope value of industrial benzaldehyde produced by the catalytic oxidation of toluene is profoundly positive, usually in the range +300‰ to +500‰. Synthetic routes leading to amphetamine, methylamphetamine or their precursors and commencing with such benzaldehyde may be expected to exhibit unusually positive δ2H values. Results are presented for δ13C and δ2H isotope values of 1‐phenyl‐2‐nitropropene synthesized from an industrial source of benzaldehyde, having a positive δ2H isotope value, by a Knoevenagel condensation with nitroethane. Results are also presented for δ13C and δ2H isotope values for amphetamine prepared from the resulting 1‐phenyl‐2‐nitropropene. The values obtained were compared with δ13C and δ2H isotope values obtained for an amphetamine sample prepared using a synthetic route that did not involve benzaldehyde. Finally, results are presented for samples of benzaldehyde, 1‐phenyl‐2‐nitropropene and amphetamine that had been seized at a clandestine amphetamine laboratory. Copyright © 2010 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.
Toward milk speciation through the monitoring of casein proteotypic peptides
Authors: Cuollo Marina , Caira Simonetta , Fierro Olga , Pinto Gabriella , Picariello Gianluca , Addeo Francesco 
Published: May 2010

AbstractThe possibility of detecting extraneous milk in singles species cheese‐milk has been explored. A mass spectrometry (MS)‐based procedure has been developed to detect 'signature peptides', corresponding to the predefined subset of 'proteotypic peptides', as matchless analytical surrogates of the parent caseins. Tryptic digests of skimmed milk samples from four species were analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) MS. Amongst the candidate signature peptides that are able to differentiate milks from the four species, the αs1‐casein (CN) f8‐22 peptide was selected as a convenient marker for bovine, ovine and water buffalo milk while the f4‐22 peptide was selected as a marker for the two caprine αs1‐CN A and B variants, which differ by a Pro16 (B)‐>Leu16 (A) substitution. MALDI analysis of the digest allowed the detection of αs1‐CN f8‐22 and caprine αs1‐CN f4‐22. The accurate evaluation of caprine milk in a quaternary mixture required the development of a liquid chromatography/electrospray ionization (LC/ESI)‐MS procedure. Five synthetic signature peptide analogues, which differed from their natural counterparts by a single amino acid substitution, were used as internal standards to quantify the αs1‐CN, which was chosen as a reference milk protein, from the different species. The limits of detection were 0.5% (1% for caprine) for either the MALDI or the LC/ESI‐MS method. The isotopic‐label‐free quantification of isoform‐ or variant‐specific signature peptides has disclosed a convenient approach for targeting proteins in complex mixtures. Copyright © 2010 John Wiley & Sons, Ltd.
A gas chromatography/mass spectrometry method for the determination of sildenafil, vardenafil and tadalafil and their metabolites in human urine
Authors: Strano‐Rossi Sabina , Anzillotti Luca , de la Torre Xavier , Botrè Francesco 
Published: May 2010

AbstractSildenafil (SDF), vardenafil (VDF) and tadalafil (TDF) are phosphodiesterase type 5 enzyme inhibitors (PDE5Is), used in the treatment of erectile disorders and to improve breathing efficiency in pulmonary hypertension. The increasing incidence of their use among young athletes has drawn the attention of the anti‐doping authorities to the possible abuse of PDE5Is by athletes due to their pharmacological activities. This paper describes a method for the determination in urine of PDE5Is and their metabolites by gas chromatography/mass spectrometry (GC/MS) after liquid/liquid extraction of the analytes from urine and derivatisation to obtain trimethylsilyl derivatives. The metabolic profile was studied on real samples collected from subjects taking PDE5Is (Viagra®, Levitra® or Cialis®); the main urinary metabolites were identified and their MS fragmentation characterized. The sample pre‐treatment and GC/MS conditions for the detection of the metabolites have been optimised. A method for their preliminary screening and subsequent confirmation is described that takes into account the general requirements of a routine doping analysis to be used for the screening of large numbers of samples. The main metabolites identified can be included in a general purpose screening method and all the metabolites in a more specific confirmation method. The method developed has been applied for the screening of PDE5Is in 5000 urine samples. Based on the obtained results, the proposed method appears to be of practical use in analytical and forensic toxicology, including doping analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Ephrins Negatively Regulate Cell Proliferation in the Epidermis and Hair Follicle
Authors: Genander Maria , Holmberg Johan , Frisén Jonas 
Published: May 2010

Abstract
Ephrins and their Eph tyrosine kinase receptors control many processes during embryonic development. They have more recently also been identified as important regulators of proliferation of stem/progenitor cells in the adult brain and intestine and have been implicated in tumorigenesis in a large number of tissues. We here describe the expression of a large number of ephrins and Eph receptors in the adult mouse skin. Disruption of the ephrin-Eph interaction in vivo with antagonists against the A or B class resulted in an approximate doubling of cell proliferation in the hair follicle and epidermis of adult mice. We conclude that ephrins are negative regulators of proliferation in the skin and that blocking the ephrin-Eph interaction may be an attractive strategy for regenerative therapies.
Afferent Loop Obstruction After Distal Gastrectomy with Roux‐en‐Y Reconstruction
Authors: Aoki Masaru , Saka Makoto , Morita Shinji , Fukagawa Takeo , Katai Hitoshi 
Published: May 2010

AbstractBackgroundThe incidence of afferent loop obstruction after gastrectomy with Roux‐en‐Y reconstruction has not yet been reported. The aim of this study was to elucidate the incidence of afferent loop obstruction after distal gastrectomy with Roux‐en‐Y reconstruction performed through an open approach.MethodsWe conducted a retrospective review of the data of 1908 patients who underwent distal gastrectomy followed by Roux‐en‐Y reconstruction through an open approach between January 1999 and December 2008.ResultsFour patients (0.2%) developed afferent loop obstruction. The median age of the patients, consisting of three men and one woman, was 64 years (range 46–78 years). The cause of the afferent loop obstruction was internal herniation in two patients, adhesion in one patient, and peritoneal recurrence in one patient. The internal herniation occurred at the mesenteric gap in the region of the jejunojejunostomy. The interval between the initial gastrectomies and the emergency operations for afferent loop obstruction ranged from 3 weeks to 2 years (median 5 months). Three of the four patients were symptomatic, with vomiting and abdominal pain. All patients recovered following the emergency operations, and none died of this complication.ConclusionsAfferent loop obstruction develops rarely after distal gastrectomy with Roux‐en‐Y reconstruction through an open approach. This rare but fatal complication should be considered when a patient complains of abdominal pain and/or vomiting after distal gastrectomy with Roux‐en‐Y reconstruction.
Stenosis of Esophago‐jejuno Anastomosis After Gastric Surgery
Authors: Fukagawa Takeo , Gotoda Takuji , Oda Ichiro , Deguchi Yasunori , Saka Makoto , Morita Shinji , Katai Hitoshi 
Published: May 2010

AbstractBackgroundStenosis of esophago‐jejuno anastomosis is one of the postoperative complications of gastric surgery. This complication usually manifests with the symptom of dysphagia and is treated by endoscopic dilatation. No large‐scale studies have been conducted to determine the incidence of this complication after surgery.MethodsThe data of a total of 1478 consecutive patients who underwent total, proximal, or completion gastrectomy, including esophago‐jejuno anastomosis, between 2000 and 2008 were analyzed retrospectively with a view to determining the incidence of anastomotic stenosis.ResultsSixty patients (4.1%) developed stenosis of the esophago‐jejuno anastomosis which needed to be treated by endoscopic balloon dilatation. The average interval between the surgery and detection of stenosis was 67.4 days (median = 58.0). Multivariate analysis identified female gender, proximal gastrectomy, use of a narrow‐sized stapler, and the choice of the stapling device as significant factors influencing the risk of development of anastomotic stenosis.ConclusionEsophago‐jejuno anastomotic stenosis appears to be a common late postoperative complication after gastric surgery. Endoscopic examination and treatment yielded favorable outcomes in patients complaining of dysphagia after gastric surgery.
Large dilating balloon to allow endoscope insertion for successful endoscopic retrograde cholangiopancreatography in patients with surgically altered anatomy (with video)
Authors: Itoi Takao , Sofuni Atsushi , Itokawa Fumihide 
Published: May 2010

AbstractBackground and purposeEndoscopic retrograde cholangiopancreatography (ERCP) in patients with surgically altered anatomy can be present unique challenges. One of the major obstacles preventing successful ERCP is acute angulation and long afferent loops in patients with Billroth II gastrectomy or Roux‐en‐Y anastomosis. Here, we described a novel technique for successful endoscope insertion using a large dilating balloon.MethodsThe large dilating balloon (maximum diameter 20 mm) is used as an anchor for endoscope insertion (hooking method) in patients with Billroth II gastrectomy in whom no other endoscopes could be advanced into the end of the duodenum or the Roux‐en‐Y anastomosis.ResultsThe hooking method allows the endoscope to be advanced into the proximal afferent loop, even in patients with sharp angulation of the Y limb.ConclusionsTo the best of our knowledge, this is the first report on the use of a large dilating balloon for endoscope insertion in patients with surgically altered anatomy, in particular Roux‐en‐Y anastomosis. We believe this technique may be effective for difficult cases like the present case.
Mitochondrial tRNALeu(UUR) mutation m.3302A > G presenting as childhood‐onset severe myopathy: threshold determination through segregation study
Authors: Ballhausen Diana , Guerry Frédéric , Hahn Dagmar , Schaller André , Nuoffer Jean‐Marc , Bonafé Luisa , Jeannet Pierre‐Yves , Jacquemont Sebastien 
Published: May 2010

AbstractMitochondrial tRNALeu(UUR) mutation m.3302A > G is associated with respiratory chain complex I deficiency and has been described as a rare cause of mostly adult‐onset slowly progressive myopathy. Five families with 11 patients have been described so far; 5 of them died young due to cardiorespiratory failure. Here, we report on a segregation study in a family with an index patient who already presented at the age of 18 months with proximal muscular hypotonia, abnormal fatigability, and lactic acidosis. This early‐onset myopathy was rapidly progressive. At 8 years, the patient is wheel‐chair bound, requires nocturnal assisted ventilation, and suffers from recurrent respiratory infections. Severe complex I deficiency and nearly homoplasmy for m.3302A > G were found in muscle. We collected blood, hair, buccal swabs and muscle biopsies from asymptomatic adults in this pedigree and determined heteroplasmy levels in these tissues as well as OXPHOS activities in muscle. All participating asymptomatic adults had normal OXPHOS activities. In contrast to earlier reports, we found surprisingly little variation of heteroplasmy levels in different tissues of the same individual. Up to 45% mutation load in muscle and up to 38% mutation load in other tissues were found in non‐affected adults. The phenotypic spectrum of tRNALeu(UUR) m.3302A > G mutation seems to be wider than previously described. A threshold of more than 45% heteroplasmy in muscle seems to be necessary to alter complex I activity leading to clinical manifestation. The presented data may be helpful for prognostic considerations and counseling in affected families.
Glycosphingolipid storage leads to the enhanced degradation of the B cell receptor in Sandhoff disease mice
Authors: te Vruchte Danielle , Jeans Aruna , Platt Frances M. , Sillence Daniel John 
Published: May 2010

AbstractGlycosphingolipid storage diseases are a group of inherited metabolic diseases in which glycosphingolipids accumulate due to their impaired lysosomal breakdown. Splenic B cells isolated from NPC1, Sandhoff, GM1‐gangliosidosis and Fabry disease mouse models showed large (20‐ to 30‐fold) increases in disease specific glycosphingolipids and up to a 4‐fold increase in cholesterol. The magnitude of glycosphingolipid storage was in the order NPC1 > Sandhoff ∼ GM1 gangliosidosis > Fabry. Except for Fabry disease, glycosphingolipid storage led to an increase in the lysosomal compartment and altered glycosphingolipid trafficking. In order to investigate the consequences of storage on B cell function, the levels of surface expression of B cell IgM receptor and its associated components were quantitated in Sandhoff B cells, since they are all raft‐associated on activation. Both the B cell receptor, CD21 and CD19 had decreased cell surface expression. In contrast, CD40 and MHC II, surface receptors that do not associate with lipid rafts, were unchanged. Using a pulse chase biotinylation procedure, surface B cell receptors on a Sandhoff lymphoblast cell line were found to have a significantly decreased half‐life. Increased co‐localization of fluorescently conjugated cholera toxin and lysosomes was also observed in Sandhoff B cells. Glycosphingolipid storage leads to the enhanced formation of lysosomal lipid rafts, altered endocytic trafficking and increased degradation of the B cell receptor.
Simulating activity of the bacterial ribosome
Authors: Trylska Joanna 
Published: May 2010

AbstractComputational modeling studies that investigate activity of the bacterial ribosome were reviewed. Computational approaches became possible with the availability of three-dimensional atomic resolution structures of the ribosomal subunits. However, due to the enormous size of the system, theoretical efforts to study the ribosome are few and challenging. For example, to extend the simulation timescales to biologically relevant ones, often, reduced models that require tedious parameterizations need to be applied. To that end, modeling of the ribosome focused on its internal dynamics, electrostatic properties, inhibition by antibiotics, polypeptide folding in the ribosome tunnel and assembly mechanisms driving the formation of the small ribosomal subunit.
Protein characterisation by synchrotron radiation circular dichroism spectroscopy
Authors: Wallace B. A. 
Published: May 2010

AbstractCircular dichroism (CD) spectroscopy is a well-established technique for the study of proteins. Synchrotron radiation circular dichroism (SRCD) spectroscopy extends the utility of conventional CD spectroscopy (i.e. using laboratory-based instruments) because the high light flux from a synchrotron enables collection of data to lower wavelengths, detection of spectra with higher signal-to-noise levels and measurements in the presence of strongly absorbing non-chiral components such as salts, buffers, lipids and detergents. This review describes developments in instrumentation, methodologies and bioinformatics that have enabled new applications of the SRCD technique for the study of proteins. It includes examples of the use of SRCD spectroscopy for providing static and dynamic structural information on molecules, including determinations of secondary structures of intact proteins and domains, assessment of protein stability, detection of conformational changes associated with ligand and drug binding, monitoring of environmental effects, examination of the processes of protein folding and membrane insertion, comparisons of mutant and modified proteins, identification of intermolecular interactions and complex formation, determination of the dispositions of proteins in membranes, identification of natively disordered proteins and their binding partners and examination of the carbohydrate components of glycoproteins. It also discusses how SRCD can be used in conjunction with macromolecular crystallography and other biophysical techniques to provide a more complete picture of protein structures and functions, including how proteins interact with other macromolecules and ligands. This review also includes a discussion of potential new applications in structural and functional genomics using SRCD spectroscopy and future instrumentation and bioinformatics developments that will enable such studies. Finally, the appendix describes a number of computational/bioinformatics resources for secondary structure analyses that take advantage of the improved data quality available from SRCD. In summary, this review discusses how SRCD can be used for a wide range of structural and functional studies of proteins.
Aperiodicity and cofinality for finitely aligned higher-rank graphs
Authors: LEWIN PETER , SIMS AIDAN 
Published: May 2010

AbstractWe introduce new formulations of aperiodicity and cofinality for finitely aligned higher-rank graphs Λ, and prove thatC*(Λ) is simple if and only if Λ is aperiodic and cofinal. The main advantage of our versions of aperiodicity and cofinality over existing ones is that ours are stated in terms of finite paths. To prove our main result, we first characterise each of aperiodicity and cofinality of Λ in terms of the ideal structure ofC*(Λ). In an appendix we show how our new cofinality condition simplifies in a number of special cases which have been treated previously in the literature; even in these settings our results are new.
Diamond aggregation
Authors: KAGER WOUTER , LEVINE LIONEL 
Published: May 2010

AbstractInternal diffusion-limited aggregation is a growth model based on random walk in ℤd. We study how the shape of the aggregate depends on the law of the underlying walk, focusing on a family of walks in ℤ2 for which the limiting shape is a diamond. Certain of these walks—those with a directional bias toward the origin—have at most logarithmic fluctuations around the limiting shape. This contrasts with the simple random walk, where the limiting shape is a disk and the best known bound on the fluctuations, due to Lawler, is a power law. Our walks enjoy a uniform layering property which simplifies many of the proofs.
Simultaneous Diophantine approximation in the real, complex and p–adic fields.
Authors: BUDARINA NATALIA , DICKINSON DETTA , BERNIK VASILI 
Published: May 2010

AbstractIn this paper it is shown that if the volume sum ∑r = 1∞ Ψ(r) converges for a monotonic function Ψ then the set of points (x, z, w) ∈ ℝ × ℂ × ℚp which simultaneously satisfy the inequalities |P(x)| ≤ H−v1 Ψλ1(H), |P(z)| ≤ H−v2 Ψλ2(H) and |P(w)|p ≤ H−v3 Ψλ3(H) with v1 + 2v2 + v3 = n − 3 and λ1 + 2λ2 + λ3 = 1 for infinitely many integer polynomials P has measure zero.
Invariants of 3-manifolds derived from covering presentations
Authors: HATAKENAKA ERI 
Published: May 2010

AbstractBy a covering presentation of a 3-manifold, we mean a labelled link (i.e., a link with a monodromy representation), which presents the 3-manifold as the simple 4-fold covering space of the 3-sphere branched along the link with the given monodromy. It is known that two labelled links present a homeomorphic 3-manifold if and only if they are related by a finite sequence of some local moves. This paper presents a method for constructing topological invariants of 3-manifolds based on their covering presentations. The proof of the topological invariance is shown by verifying the invariance under the local moves. As an example of such invariants, we present the Dijkgraaf–Witten invariant of 3-manifolds.