bluuebunny/crossref_metadata_2025_split huggingface dataset:
SERS detection of red organic dyes in Ag‐agar gel
Authors: Lofrumento Cristiana , Ricci Marilena , Platania Elena , Becucci Maurizio , Castellucci Emilio 
Published: September 2012

Micro‐Raman spectroscopy has been widely employed in the last few years for the study of artworks, allowing for the characterization of a high class of pictorial materials. However, the detection of organic dyes by conventional Raman spectroscopy is quite difficult, due to the high fluorescence provided by these compounds. Recently, remarkable improvements have been achieved by the introduction of the surface enhanced Raman spectroscopy (SERS) technique for the analysis of organic dyes.In the present work, a new method is presented, based on the use of a SERS probe made of agar‐agar coupled with silver nanoparticles, for a non‐destructive and minimally invasive micro‐extraction of dyes from textiles. Ag‐agar gel has been tested first on textile mock‐ups dyed with alizarin, purpurin and carminic acid. SERS measurements have been performed adopting laser light excitations at 514.5 and 785 nm of a micro‐Raman setup. Highly structured SERS band intensities have been obtained. After having verified the safety of the method by colorimetric, X‐ray fluorescence and attenuated total reflectance Fourier transform infrared techniques, a real case, a pre‐Columbian piece of textile, have been investigated by Ag‐agar gel. This cutting‐edge method offers new possibilities for a sensitive and non‐destructive analysis of fluorescent materials. Copyright © 2012 John Wiley & Sons, Ltd.
Micro‐Raman analysis and finite‐element modeling of 3 C‐SiC microstructures
Authors: Piluso N. , Anzalone R. , Camarda M. , Severino A. , La Magna A. , D'Arrigo G. , La Via F. 
Published: September 2012

Micro‐ and nano‐electromechanical systems (MEMS and NEMS) fabricated in 3 C‐SiC are receiving particular attention thanks to the material physical properties: its wide band gap (2.3 eV), its ability to operate at high temperatures, its mechanical strength and its inertness to the exposure in corrosive environments. However, high residual stress (which is normally generated during the hetero‐epitaxial growth process) makes the use of 3 C‐SiC in Si‐based MEMS fabrication techniques very limited leading to a failure of micro‐machined/sensor structures.In this paper, micro‐Raman characterizations and finite‐element modeling (FEM) of microstructures realized on poly and single‐crystal (100) 3 C‐SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm−1) respect to the stressed unreleased region (795.7 cm−1). Also, microstructures as cantilever, bridge and planar rotating probe show an intense stress field located around the undercut region. Here, the TO Raman mode undergoes an intense shift, up to 2 cm−1, ascribed to the modification of the Raman stress tensor. Indeed, the generalized axial regime, described by diagonal components of the Raman stress tensor, cannot be applied in this region. Raman maps analysis and FEM simulations show the ‘activation’ of the shear stress, i.e. non‐diagonal components of the stress tensor. The stress‐Raman modes shift correlation, in the case of fully non‐diagonal stress tensors, has been investigated. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer. Copyright © 2012 John Wiley & Sons, Ltd.
A Fast Method to Compute the MSD and MWD of Polymer Populations Formed by Step‐Growth Polymerization of Polyfunctional Monomers Bearing A and B Coreactive Groups
Authors: Hillegers L. Tom , Blokhuis Aart , Slot Johan J. M. 
Published: September 2012

AbstractGeneral step‐growth polymerization systems of order 2 are considered, i.e., systems of type “AfiBgi”, and a fast algorithmic method is presented to compute, at a given degree of conversion, the MSD and the MWD. The complete distribution is calculated; not just statistical averages of the polymer population such as $\overline {M} _{{\rm n}} $ or $\overline {M} _{{\rm w}} $. For the computation of the low‐ and intermediate size/weight parts of the distribution curves, a set of recurrence relations is used. The high‐molecular size/weight parts of the curves (right tails) are computed using an accurate approximation derived from generating functions. In a previous paper, we applied our method to general order‐1 systems, i.e., systems of type “Afi”. magnified image
Influence of 1,5‐naphthalenediamine on thermomechanical properties of epoxy/copolyethersulphone blends
Authors: Cicala G. , Blanco I. , Latteri A. , Oliveri L. , Recca A. 
Published: August 2012

AbstractThe use of 1,5‐naphthalenediamine (ND) as curing agents for epoxy blends was studied. The epoxy monomer was a standard diglycidyl ether of bisphenol A while as modifier a laboratory made copolyethersulphone (coPES) was considered. The coPES was added at three percentages: 10, 20, and 30% wt. The stiff structure of ND increased both viscosity and glass transition temperature of the blends. The blends cured by ND showed higher viscosity compared to resins cured by 3,3′‐diammino diphenylsulfone or 4,4′‐methylenebis(2,6‐diethylaniline). Blends with higher coPES content (20 and 30% wt) showed viscosity fluctuation suggesting phase separation initiation but the combination of high viscosity and reactivity hindered the demixing process. This effect resulted in single glass transition for all formulations confirming the absence of phase separation. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Study of rheological, thermal, and mechanical behavior of reprocessed polyamide 6
Authors: Crespo J.E. , Parres F. , Peydró M.A. , Navarro R. 
Published: August 2012

AbstractThe effect of reprocessing Polyamide 6 (PA6) has been studied in this article. To simulate recycled PA, we reprocessed virgin PA through five cycles. The PA 6 has undergone mechanical, thermal and rheological characterization after the various cycles of reprocessing in order to evaluate the corresponding properties and correlate them with the number of cycles undergone. In order to widen our injection simulation analysis by computer (CAE: Computer Aided Engineering) of these new materials, it was necessary to determine the viscosity using a mathematical model; in this case the Cross‐WLF, to determine the relevant parameters. Our results show that tensile strength, elongation at break and hardness remain practically constant, while the charpy impact decreases as the number of reprocessing cycles increases. The effects of reprocessing on the material may decrease the rheological properties; specifically the viscosity of the material decreases with increasing processing cycles. The thermal properties are also influenced with the reprocessed material. The crystallinity increases and the degradation reaction will be advanced to increase the reprocessing cycle. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Dielectric behavior of aluminum hydroxide‐filled oil‐extended ethylene‐propylene‐diene‐monomer rubber composites in microwave fields
Authors: Nair Ajalesh Balachandran , Kalappura Ullas G. , Kurian Philip , Joseph Rani 
Published: September 2012

AbstractOil‐extended ethylene‐propylene‐diene rubber composites were prepared with aluminum hydroxide (ATH) and high abrasion furnace carbon black. The dielectric properties at microwave frequencies of the samples were measured in the S (2–4 GHz) band using cavity perturbation technique. The thermal stability of the composites was studied using thermogravimetric analysis. The morphology of the composites was investigated by scanning electron microscopic studies. The fire retardancy of the composites was identified through the limiting oxygen index and horizontal burning test (UL94 HB). The dielectric permittivity, AC conductivity, and absorption coefficient of the highly ATH loaded systems are much greater than the unfilled and lower systems. At higher loading, the dielectric heating coefficient and skin depth were found to decrease significantly. The incorporation of ATH was found to improve the thermal stability and flame retardancy of EPDM. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Practical considerations in the determination of compound‐specific amino acid δ15N values in animal and plant tissues by gas chromatography‐combustion‐isotope ratio mass spectrometry, following derivatisation to their N‐acetylisopropyl esters
Authors: Styring Amy K. , Kuhl Alison , Knowles Timothy D. J. , Fraser Rebecca A. , Bogaard Amy , Evershed Richard P. 
Published: September 2012

RATIONALEStable nitrogen isotope (δ15N) values of bone collagen are routinely used to inform interpretations of diet and trophic positions within contemporary and ancient ecosystems, yet the underlying physiological and biochemical factors which contribute to the bulk collagen δ15N value remain little understood. Determination of individual amino acid (AA) δ15N values in animal and plant proteins can help to elucidate the cycling of nitrogen and inform predictions of palaeodiet and ecology.METHODSIn this study we present a methodology for the measurement of amino acid δ15N values using gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). Amino acid standards of known δ15N values were derivatised to their N‐acetylisopropyl (NAIP) esters and purified through Dowex ion‐exchange resin to determine any isotopic fractionation associated with derivatisation and ion‐exchange chromatography. The effect of starch on AA δ15N values was also determined by hydrolysing bone collagen with and without the presence of starch.RESULTSThe amino acids derivatised to their NAIP esters give values within ±0.8‰ of their δ15N values measured separately by elemental analyser (EA)‐IRMS, with a precision of better than 0.8‰. The δ15N values of AAs after Dowex ion‐exchange chromatography were within ±0.9‰ of their values prior to ion‐exchange chromatography. The AA δ15N values of bone collagen hydrolysed with and without starch were within ±0.8‰.CONCLUSIONSHydrolysis of lipid‐extracted plant material followed by purification of AAs using Dowex ion‐exchange resin and derivatisation to their NAIP esters is a suitable protocol for the accurate determination of individual plant and animal AA δ15N values by GC‐C‐IRMS. Copyright © 2012 John Wiley & Sons, Ltd.
High molecular weight non‐polar hydrocarbons as pure model substances and in motor oil samples can be ionized without fragmentation by atmospheric pressure chemical ionization mass spectrometry
Authors: Hourani Nadim , Kuhnert Nikolai 
Published: September 2012

RATIONALEHigh molecular weight non‐polar hydrocarbons are still difficult to detect by mass spectrometry. Although several studies have targeted this problem, lack of good self‐ionization has limited the ability of mass spectrometry to examine these hydrocarbons. Failure to control ion generation in the atmospheric pressure chemical ionization (APCI) source hampers the detection of intact stable gas‐phase ions of non‐polar hydrocarbon in mass spectrometry.METHODSSeventeen non‐volatile non‐polar hydrocarbons, reported to be difficult to ionize, were examined by an optimized APCI methodology using nitrogen as the reagent gas.RESULTSAll these analytes were successfully ionized as abundant and intact stable [M–H]+ ions without the use of any derivatization or adduct chemistry and without significant fragmentation. Application of the method to real‐life hydrocarbon mixtures like light shredder waste and car motor oil was demonstrated.CONCLUSIONSDespite numerous reports to the contrary, it is possible to ionize high molecular weight non‐polar hydrocarbons by APCI, omitting the use of additives. This finding represents a significant step towards extending the applicability of mass spectrometry to non‐polar hydrocarbon analyses in crude oil, petrochemical products, waste or food. Copyright © 2012 John Wiley & Sons, Ltd.
Surfactant self‐assembling in the gas phase: bis(2‐ethylhexyl)‐sulfosuccinate divalent metal ion anionic aggregates
Authors: Giorgi Gianluca , Ceraulo Leopoldo , Liveri Vincenzo Turco 
Published: September 2012

RATIONALEInvestigation of fundamental aspects driving surfactant self‐assembling and of the capability of including guest molecules or ions in their micellar aggregates is an exciting research field for theoretical and technological reasons. In this light, assembling and chelating properties of sodium bis(2‐ethylhexyl)sulfosuccinate (AOTNa) towards divalent metal ion chlorides have been investigated in the gas phase by electrospray ionization mass spectrometry in negative ion mode, tandem mass spectrometry and energy‐resolved mass spectrometry.METHODSWater/methanol solutions of AOTNa and chloride salts of nickel, magnesium, calcium and manganese, with different AOTNa/metal salt ratios, were infused into the electrospray source of a LCQ DECA ion trap mass spectrometer, operating in negative ion mode, at a flow rate of 5 μL/min. Low energy collision‐induced dissociations were carried out by using helium with collision energy in the range 1–5 eV.RESULTSA variety of negatively singly charged monometallated and mixed metal aggregates have been observed, some of which were able to incorporate the metal counter ion of the inorganic salt used. The stability of these aggregates was evaluated by energy‐resolved mass spectrometry which showed, for the anions [AOTMIICl2]–, a stability order Ca > Mn > Mg > Ni. Their decomposition pathways show the unusual formation of the radical anions [C4HO6SMIICl]–•.CONCLUSIONSThis study shed some light on the assembling and chelating properties of AOT– towards divalent metal ions to form negatively charged assemblies, some of them incorporating the metal counter ion of the inorganic salt used. Differently from what was observed with positively charged AOT‐MII aggregates, solvated species were not detectable. An exception to the even‐electron rule was observed in the decomposition pathway of [AOTMIICl2]–. Copyright © 2012 John Wiley & Sons, Ltd.
Quantification of cardiolipin molecular species in Escherichia coli lipid extracts using liquid chromatography/electrospray ionization mass spectrometry
Authors: Garrett Teresa A. , O'Neill Ashley C. , Hopson Marquise L. 
Published: September 2012

RATIONALECardiolipin (CL), a glycerophospholipid containing four acyl chains, is found in most organisms including Gram‐negative bacteria such as Escherichia coli. While CL composes only a fraction of the total glycerophospholipids, the four acyl chains lead to a large number of possible molecular species as defined by the total number of carbons and unsaturations in the acyl chains. Understanding the molecular composition of CL, and how it changes under different growth conditions, will aid in understanding the complex role of CL in E. coli.METHODSNormal‐phase liquid chromatography/electrospray ionization mass spectrometry was used to quantify the CL molecular species (as defined by the total number of carbons:unsaturations in the acyl chains) in lipid extracts prepared from E. coli grown at 15 °C, 30 °C, 37 °C and 42 °C.RESULTSFifty‐six different CL species were identified as [M–2H]2– ions in E. coli lipid extracts ranging from 60:0 to 72:4. CL species with an increased total number of unsaturations were more abundant in lipid extracts prepared from cells grown at 15 °C as compared to higher temperatures.CONCLUSIONSThis work characterizes the CL composition of E. coli cells grown at various temperatures. By quantifying CL species at a molecular level we have illuminated the molecular complexity of the CL in this relatively simple model organism. This data will be useful for understanding CL function in E. coli and other organisms. Copyright © 2012 John Wiley & Sons, Ltd.
Impact of Posttransplantation Glomerulonephritis on Long‐term Outcome of Kidney Transplants: Single‐Center 20‐Year Experience
Authors: Yu Tung‐Min , Wen Mei‐Chin , Wu Ming‐Ju , Chen Cheng‐Hsu , Cheng Chi‐Hung , Li Chi‐Yuan , Shu Kuo‐Hsiung 
Published: September 2012

AbstractBackgroundSuccessful renal transplantation has been performed in patients with end‐stage renal disease and has been routine in patients with end‐stage renal failure for more than two decades. Despite advances in the use of immunosuppressants, there has been only modest improvement in long‐term allograft survival. Accumulating data have demonstrated that chronic rejection and recurrent glomerulonephritis are major causes of long‐term allograft loss. However, data regarding the long‐term impact of posttransplantation glomerulonephritis (PTGN) on ethnic Chinese populations are still unavailable.MethodsFrom 1984 to 2010, a total of 268 patients who underwent renal allograft biopsies were reviewed retrospectively. Renal outcomes were compared by Kaplan–Meier analysis, and risk factors for renal survival and all‐cause mortality were analyzed using the Cox proportional hazards model.ResultsIn all, 85 patients (31.7 %) had PTGN, and the mean time of disease onset was 5.32 ± 5.18 years after transplantation. Among the 85 PTGN cases, 33 (39 %) were immunoglobulin A (IgA) nephropathy, 24 (28 %) were focal segmental glomerulosclerosis, and 8 (9.4 %) were membranous GN. Significant risk was associated with posttransplant IgA GN in hepatitis B virus carriers (odds ratio 5.371, 95 % confidence interval 1.68, 17.19; p = 0.0064). A total of 45 PTGN patients had allograft loss, of whom 49 % had IgA nephropathy. Patients with PTGN had inferior allograft survival rates compared to those with other pathologic findings (p < 0.0003).ConclusionsTaken together, our results indicate that PTGN had a strong negative impact on long‐term kidney graft survival. Posttransplant IgA nephropathy is a leading cause of allograft loss in Chinese kidney transplant patients with PTGN.
Dynamics of phase fronts in magmagenic fluid in the formation of gold and silver deposits in Southern Kamchatka
Authors: Sharapov V.N. , Lapukhov A.S. , Guzman B.V. , Cherepanova V.K. 
Published: September 2012

Abstract
The origin of gold and silver deposits in the Southern Kamchatka ore district is considered in terms of a quantitative model of the dynamics of volcanogenic orthomagmatic fluid systems (VOFSs). This model takes into account structural, fluid dynamic, and thermophysical features of phase evolution in hydrothermal fluid systems differing in geometry and structural conditions of the discharge on the surfaces of volcanic edifices. It is shown that VOFSs forming sulfide-rich gold and silver deposits have no stationary impermeable caps in their discharge areas. Rather, for the most part, narrow regions of junction of phase fronts form in their interiors and migrate to the surface of volcanic edifices.
Three geothermal system types are predicted by the example of plane and conical fluid conductance zones with a cap horizon: (I) where the shallow decompression boiling zone does not arise at all because of large lateral heat loss, (II) where subsurface decompression boiling zones appear at the beginning of the heat wave formation and then such a zone is practically confined to the cap rocks, and (III) where a quasistationary decompression boiling zone forms after an initial instability period or approach to a thermal equilibrium. Fluctuations or oscillations of decompression boiling zone fronts within a range of depths can exist in type III systems.
Neotectonics and paleoseismicity of the lower Katun’ valley (Gorny Altai)
Authors: Deev E.V. , Zolnikov I.D. , Borodovsky A.P. , Goltsova S.V. 
Published: September 2012

Abstract
The lower Katun’ area has a complex neotectonic framework, with the largest fault zone of Katun’ consisting of several en-echelon graben segments. Late Pleistocene sediments that fill the Katun’ Fault bear signature of earthquake-induced soft-sediment deformation (seismites). Deformation due to seismic triggers can be discriminated from nonseismic one on the basis of special features and be related to prehistoric earthquakes according to a number of criteria. The observed deformation inside and outside burial mounds of the Chultukov Log-1 group may result from an earthquake that occurred in the end of the first millennium BC. Fault scarps in Late Pleistocene sediments, as well as deformed Iron Age tomb patterns, indicate that the Katun’ lower reaches can have experienced past earthquakes of intensity at least 5 or 6 and magnitudes from 4.5 to 6.0.
Current radiation environment in the Central Ecological Zone of the Baikal Natural Territory
Authors: Chernyago B.P. , Nepomnyashchikh A.I. , Medvedev V.I. 
Published: September 2012

Abstract
The main natural and human-induced radiation factors were assessed on the basis of long-term targeted radioecological studies in the Central Ecological Zone of the Baikal Natural Territory as a world heritage site. We identified areas with a problematic level of different radiation parameters determining the current radiation environment. Such areas should be taken into account in the development and implementation of nature management plans in the Baikal region, including ecotourism.
The critical layer in linear-shear boundary layers over acoustic linings
Authors: Brambley E. J. , Darau M. , Rienstra S. W. 
Published: August 2012

AbstractAcoustics within mean flows are governed by the linearized Euler equations, which possess a singularity wherever the local mean flow velocity is equal to the phase speed of the disturbance. Such locations are termed critical layers, and are usually ignored when estimating the sound field, with their contribution assumed to be negligible. This paper studies fully both numerically and analytically a simple yet typical sheared ducted flow in order to investigate the influence of the critical layer, and shows that the neglect of critical layers is sometimes, but certainly not always, justified. The model is that of a linear-then-constant velocity profile with uniform density in a cylindrical duct, allowing exact Green’s function solutions in terms of Bessel functions and Frobenius expansions. For sources outside the sheared flow, the contribution of the critical layer is found to decay algebraically along the duct as $O(1/ {x}^{4} )$, where $x$ is the distance downstream of the source. For sources within the sheared flow, the contribution from the critical layer is found to consist of a non-modal disturbance of constant amplitude and a disturbance decaying algebraically as $O(1/ {x}^{3} )$. For thin boundary layers, these disturbances trigger the inherent convective instability of the flow. Extra care is required for high frequencies as the critical layer can be neglected only in combination with a particular downstream pole. The advantages of Frobenius expansions over direct numerical calculation are also demonstrated, especially with regard to spurious modes around the critical layer.