bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization and Physical Ageing of Poly (2‐vinyl pyridine)‐b‐poly(ethylene oxide) Diblock Copolymers
Authors: Córdova Miguel , Lorenzo Arnaldo T. , Müller Alejandro J. , Fragouli Panagiota , Iatrou Hermis , Hadjichristidis Nikos 
Published: February 2010

AbstractSummary:A set of melt miscible Poly(2‐vinyl pyridine)‐b‐Poly(ethylene oxide) (P2VP‐b‐PEO) block copolymers of different compositions were studied. Transmission electron microscopy shows phase separation in the materials during the crystallization process of the PEO block as crystalline lamellae are observed for all compositions evaluated. The isothermal crystallization kinetics of PEO is progressively retarded as the P2VP content in the copolymer increases, since P2VP hinders molecular mobility in the miscible amorphous phase. Polarized light optical microscopy demonstrated that the glassy P2VP block has a negative effect on the secondary nucleation of the PEO. Finally, physical ageing experiments performed in the glassy state of the amorphous mixed phase, at different ageing times, demonstrated that a nucleating effect can be induced in the glassy state as a consequence of the reorganization of the amorphous regions. This nucleating effect significantly alters the cold crystallization rate upon subsequent heating above the glass transition temperature.
Influence of the Operative Conditions on the Characteristics of Poly(D,L‐lactide‐co‐glycolide) Synthesized in Supercritical Carbon Dioxide
Authors: Mazarro R. , de Lucas A. , Cabezas L. I. , Gracia I. , Rodríguez J. F. 
Published: February 2010

AbstractSummary: The co‐polymerizations of D,L‐lactide and glycolide in supercritical carbon dioxide (scCO2) using zinc (II) ethylhexanoate (ZnOct2) as catalyst and methanol as initiator have been investigated. The influence of stirring rate (N), temperature (T), and mass carbon dioxide (mCO2) on molecular weight distribution (MWD); co‐polymer composition; and conversion has been studied by means an experimental factorial design. The stirring rate has the greatest influence on conversion. Due to the heterogeneous nature of the process the mass transfer enhancement, that the grater turbulence produces, favors greatly the incorporation of monomers into the polymer phase. An important decrease of molecular weight is observed independently of reaction conditions for high conversion values because some thermal degradation or rearrangement reactions are taking place. The influence of the initiator, methanol, on the molecular weight has been also studied. Methanol acts as an effective chain transfer agent initiating more growing chains than expected, what also contributes to get low molecular weights.
Novel Functional Mesoporous Materials Obtained from Nanostructured Diblock Copolymers
Authors: Gorzolnik Blazej , Davidson Patrick , Beurroies Isabelle , Denoyel Renaud , Grande Daniel 
Published: February 2010

AbstractSummary: Novel carboxy (COOH)‐functionalized mesoporous polystyrene membranes were prepared from polystyrene‐block‐poly(D,L‐lactide) (PS‐b‐PLA) diblock copolymers through the selective degradation of the PLA block. The combination of atom transfer radical polymerization (ATRP) and ring‐opening polymerization (ROP) techniques enabled the synthesis of nanostructured diblock copolymers possessing carboxylic acid functionality at the junction between both blocks. Such copolymers were subjected to shear flow through the use of a channel die to align their nanodomains. Under mild alkaline conditions, the quantitative hydrolysis of the polyester nanodomains afforded mesoporous materials with COOH‐coated pore walls. The PS‐b‐PLA precursors as well as the resulting porous systems were carefully analyzed by size exclusion chromatography (SEC), 1H NMR, scanning electron microscopy (SEM), and two‐dimensional small‐angle X‐ray scattering (2‐D SAXS). Moreover, the specific surface area and pore size distribution were determined by nitrogen sorption porosimetry.
CVD Growth of Carbon Nanotubes and Nanofibers: Big Length and Constant Diameter
Authors: Toubestani D. Hanifeh , Ghoranneviss M. , Mahmoodi A. , Zareh M. Rahbar 
Published: February 2010

AbstractSummary: We report mass production of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with relatively high length and aspect ratio. We synthesized carbon nanomaterials by chemical vapor deposition (CVD) of methane as the feeding gas on Fe/Mo nanoparticles that use alumina‐aerogel support. Alumina‐aerogel‐supported Fe/Mo catalyst was prepared using sol‐gel. Drying step performed using rotary evaporation and freeze‐drying. CVD was performed using a quartz tube furnace. Samples were analyzed using scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy.
Using Neural Networks or Linear Models to Predict the Characteristics of Microcapsules Containing Phase Change Materials
Authors: Sánchez Luz , Sánchez Paula , De Lucas Antonio , Carmona Manuel , Rodríguez Juan Francisco 
Published: February 2010

AbstractSummary: Microcapsules with large amount of PRS® paraffin wax encapsulated and narrow size distribution were prepared by shirasu porous glass (SPG) emulsification technique and a subsequent suspension like polymerization process and then examined by DSC, laser diffraction and SEM analyses. An experimental design approach, based on a central composite design, was used to determine quantitatively the effect of PRS® paraffin wax/styrene mass ratio (PRS/St), percentage of polyvinylpyrrolidone/styrene mass ratio (%PVP/St) and water/styrene mass ratio (H2O/St) on the microparticles properties. The results were fitted using two black‐box models. The empirical equations allow the prediction of the amount of the paraffin wax encapsulated and the mean particle size in number as a function of aforementioned synthesis variables.It was observed that both models allowed to drawn the same conclusions. %PVP/St mass ratio was the most important parameter affecting the particle size distribution decreasing the average particle size with the increase of %PVP/St. On the other hand, PRS/St mass ratio has a direct influence on the latent heat of fusion.
Gel strength and swelling of acrylamide‐protic acid superabsorbent copolymers
Authors: Seetapan Nispa , Wongsawaeng Jiraporn , Kiatkamjornwong Suda 
Published: February 2010

AbstractThe viscoelastic and swelling properties of polyacrylamide‐based superabsorbent copolymers were investigated as a function of the ionic comonomer structure. Superabsorbent copolymers were synthesized by free‐radical crosslinking copolymerization of acrylamide and one of the monoprotic acids (acrylic acid and crotonic acid) or the diprotic acids (maleic acid and itaconic acid) as the investigated ionic comonomer. The reaction composition of all components, i.e. monomer, comonomer, initiator, co‐initiator, and crosslinker, was fixed to be the same for the synthesis of all four superabsorbent copolymer systems. Viscoelastic measurements were performed in all systems where the particles were closely packed. The network structures of all systems were evaluated via viscoelastic and swelling measurements. The results indicated that superabsorbent polymers (SAPs) with high water absorbency were accompanied by low gel strength and the calculated high value of molecular weight between crosslinks ($\bar {M}{}_c$) and low value of effective crosslinking density (νe). Diprotic acid‐containing SAPs showed higher water absorbency over monoprotic acid‐containing and non‐ionic ones. The differences in $\bar {M}{}_c$ and νe values of each system were explained with respect to the differences in the monomer reactivity ratio and hydrophilicity of the comonomers. Copyright © 2010 John Wiley & Sons, Ltd.
Maternal serum anti‐Mullerian hormone level is not superior to chronological age in predicting Down syndrome pregnancies
Authors: Li Hang Wun Raymond , Hui Pui Wah , Tang Mary Hoi Yin , Lau Elizabeth Tak Kwong , Yeung William Shu Biu , Ho Pak Chung , Ng Ernest Hung Yu 
Published: February 2010

AbstractObjectiveTo compare the difference in maternal serum anti‐Mullerian hormone (AMH) level between Down syndrome pregnancies and unaffected pregnancies, and to evaluate its performance as a screening marker for Down syndrome pregnancy.MethodA total of 145 pregnancies affected by foetal Down syndrome and 290 unaffected controls matched with maternal age and gestational age were selected, and their archived first or second trimester serum retrieved for AMH assay.ResultsThere was no significant difference in maternal serum AMH level between pregnancies affected and unaffected by foetal Down syndrome. Our first trimester serum samples had higher AMH concentration compared to second trimester samples.ConclusionsMaternal serum AMH level, as a marker of ovarian age, is not superior to chronological age in predicting Down syndrome pregnancies. Despite the cross‐sectional nature of our study, the variation of maternal serum AMH concentration with gestational age warrants further investigation. Copyright © 2010 John Wiley & Sons, Ltd.
A Physicochemical Approach to Render Antibacterial Surfaces on Plasma‐Treated Medical‐Grade PVC: Irgasan Coating
Authors: Asadinezhad Ahmad , Novák Igor , Lehocký Marián , Sedlařík Vladimír , Vesel Alenka , Junkar Ita , Sáha Petr , Chodák Ivan 
Published: February 2010

AbstractA multistep physicochemical approach was adopted to develop a novel surface active antibacterial medical‐grade polyvinyl chloride (PVC). This was accomplished through surface activation via diffuse coplanar surface barrier discharge plasma in air at ambient temperature and pressure, followed by radical graft copolymerization of acrylic acid onto the surface via grafting‐from pathway to yield a well‐defined high density brush. Irgasan as a potent biocide was then coated onto the functionalized surface to impart antimicrobial properties. Contact angle measurements showed an improved hydrophilicity upon multistep modifications. Alterations in surface free energy values were tracked through various known models. The equilibrium water absorption test corroborated the contact angle analysis. Scanning electron microscopy revealed etched features on the plasma treated sample as well as a brush‐like pattern on the graft copolymerized surface. Surface chemistry was explored by Attenuated Total Reflectance Fourier Transform Infrared (ATR‐FTIR) and X‐ray Photoelectron Spectroscopy (XPS), which confirmed the presence of irgasan non‐covalently anchored onto the surface. An excellent bacteriostatic performance was exhibited by the irgasan coated sample using the agar diffusion test method against two potentially pathogenic gram‐negative and particularly gram‐positive bacterial strains implying a facile release of the antibacterial agent. However, in vitro bacterial adhesion and biofilm formation assays indicated incapability of irgasan in hindering the adherence after 24 h incubation. Nevertheless, the plasma treated and graft copolymerized samples were appreciably effective to diminish the adherence of gram‐negative strain. Wettability and surface configuration of the substrate, besides bacteria structural characteristics, were established to be crucial factors in the adhesion phenomenon. The irgasan coated medical‐grade PVC was suggested to be suited for use in disposable medical catheters of dependable antimicrobial performance.magnified image
Reflection high energy electron diffraction as a tool in cluster deposition experiments
Authors: Kleibert Armin , Voitkans Andris , Meiwes‐Broer Karl‐Heinz 
Published: February 2010

AbstractReflection high energy electron diffraction (RHEED) is used to study the structure and orientation of mass‐filtered iron clusters upon deposition onto W(110). The present setup enablesin situinvestigations during deposition and thermal annealing. Particles as small as 2 nm at low density on the surface can be studied. The experiments reveal that larger particles with a diameter of about 13 nm are randomly oriented on the substrate with a preferred tendency to rest on their surface facets. Thermal annealing leads to a partial realignment and a significant flattening of the particles. In contrast 2 nm particles are found to align spontaneously in an epitaxial manner on W(110). Thermodynamic arguments suggest that thermally activated motion of dislocations is responsible for the observed alignment phenomena rather than temporary melting of the particles.magnified imageRHEED setup forin situinvestigations in cluster deposition experiments.
Spin dynamics of S = 1/2 kagome lattice antiferromagnets observed by high‐field ESR
Authors: Ohta Hitoshi , Zhang Wei‐min , Okubo Susumu , Fujisawa Masashi , Sakurai Takahiro , Okamoto Yoshihiko , Yoshida Hiroyuki , Hiroi Zenji 
Published: February 2010

AbstractDue to the existence of strong spin frustration in a system, the spin dynamics of S = 1/2 kagome lattice antiferromagnet at low temperature has attracted much interest. High‐field ESR has been measured on its model substances, Cu3V2O7(OH)2 · 2H2O (volborthite) and BaCu3V2O3(OH)2 (vesignieite), down to 1.8 K using pulsed magnetic fields up to 16 T. The measurements are performed for 160 and 315 GHz using polycrys‐talline samples. Although both samples showed the g‐shift and the change of linewidth at low temperature, volborthite showed a small gap excitation of the order of 40 GHz (1.9 K) while vesignieite showed a paramagnetic behavior down to 1.9 K. Observed difference will be discussed in connection with the crystal structure, and the possible spin liquid state in vesignieite will be discussed.
Pronounced basal plane anisotropy in the magnetoresistance of YbCo2Si2
Authors: Mufti N. , Klingner C. , Pedrero L. , Brando M. , Kaneko K. , Krellner C. , Stockert O. , Geibel C. 
Published: February 2010

AbstractWe have investigated the antiferromagnetic (AFM) state of YbCo2Si2 by means of magnetoresistance measurements for different field and current directions. We observed huge magnetoresistance effects, up to ±60% even at low fields B < 2 T, and a very rich variety of features. The results evidence a complex magnetic phase diagram, with a pronounced anisotropy even for different field directions within the basal plane. The analysis of these results gives valuable insight into the different AFM phases of YbCo2Si2.
Combination of different liquid chromatography/mass spectrometry technologies for the identification of transformation products of rhodamine B in groundwater
Authors: Müller Alexander , Weiss Stefan C. , Schulz Wolfgang , Seitz Wolfram , Albert Roger , Ruck Wolfgang K. L. , Weber Walter H. 
Published: February 2010

AbstractRhodamine B and its five de‐ethylated transformation products could be identified in a groundwater sample. Using high‐performance thin‐layer chromatography (HPTLC) six fluorescent zones were detected in the sample. In order to identify the compounds in the zones by exact mass mass spectrometry (MS) measurements and tandem mass spectrometry (MS/MS), they were extracted from the HPTLC plate for subsequent analysis by nano‐chip high‐performance liquid chromatography quadrupole‐time‐of‐flight mass spectrometry (nano‐chip HPLC/QTOFMS). In addition, chemical derivatisation experiments on HPTLC plates were applied to detect the presence of a primary amino group in the transformation products. From the combined analytical results it was possible to allocate rhodamine B and its five de‐ethylated transformation products to the six different HPTLC zones. The quantification of rhodamine B in different groundwater samples was carried out by a high‐performance liquid chromatography/triple quadrupole mass spectrometry (HPLC/MS/MS). The maximum detected concentration of rhodamine B was 83 µg L−1. Copyright © 2010 John Wiley & Sons, Ltd.
Don anonyme, secret du don et symbolique
Authors: Dudkiewicz-Sibony C. 
Published: February 2010

Résumé
À partir des entretiens psychologiques que nous avons au CECOS avec les donneurs de spermatozoïdes et les couples demandeurs, ainsi que l’analyse des témoignages d’enfants nés du don, nous souhaitons montrer que ce n’est pas l’anonymat des donneurs qui pose problème, mais le secret sur le don lui-même qui devient secret de famille lorsque le recours au don est mal accepté par les parents et qu’il produit des effets nocifs, quand l’annonce du don est faite tardivement, et est assortie d’un interdit d’en parler aux autres.
A qualitative study of the information needs of premenopausal women with breast cancer in terms of contraception, sexuality, early menopause, and fertility
Authors: Karaöz Banu , Aksu Hilmiye , Küçük Mert 
Published: February 2010

AbstractObjectivesTo evaluate the information needed and received by premenopausal Turkish women with breast cancer regarding contraception, early menopause, infertility, fertility preservation, and sexuality.MethodsA qualitative exploratory methodology was used whereby an interviewer met on 2 occasions with women with breast cancer. The participants—who were recruited from the oncology clinic of Adnan Menderes University Hospital, Aydın, Turkey—were premenopausal, younger than 50 years of age, and had been diagnosed with breast cancer within the past year. Raw data were sorted under themes.ResultsPremenopausal women with breast cancer received insufficient counseling on contraception, early menopause, infertility, fertility preservation, and sexuality, despite their willingness to receive information.ConclusionIn Turkey, premenopausal women with breast cancer should receive comprehensive information and counseling from oncology staff on the issues studied. The present study may guide future research on this topic.
Revised biochronology of the Lower Cambrian of the Central Iberian zone, southern Iberian massif, Spain
Authors: JENSEN SÖREN , PALACIOS TEODORO , MUS MONICA MARTÍ 
Published: February 2010

AbstractTrilobites from the upper unit of the Lower Cambrian Pusa Formation (south-central Spain) substantially antedate other Iberian trilobites, according to widely published correlation schemes, and arguably would be among the earliest trilobites globally. These trilobites, previously only briefly mentioned in texts, are here described and illustrated, and their biochronological context examined. The Pusa Formation trilobites are treated in open nomenclature but with suggested affinity to the genusAbadiella.They are associated with small shelly fossils, includingPelagiellasp., chancellorid spicules andCupithecasp., and unidentfied archaeocyathans. Trace fossils from the upper unit of the Pusa Formation, down-section of the trilobites, includeDactyloiditesisp. andRusophycusisp., the latter representing the lowest occurrence of this ichnogenus in the region. This biostratigraphical context demonstrates that the Pusa Formation trilobites are substantially younger than had traditionally been thought. In terms of Iberian regional stages they are Ovetian, not Corduban as previously thought. As a consequence of the data presented here, the definitions of Iberian Lower Cambrian regional stages are discussed and a substantially revised correlation between key Lower Cambrian strata of the Central Iberian and Ossa Morena zones is proposed.
Variscan sourcing of Westphalian (Pennsylvanian) sandstones in the Canonbie Coalfield, UK
Authors: MORTON ANDREW , FANNING MARK , JONES NEIL 
Published: February 2010

AbstractThe zircon age spectrum in a sample from the Canonbie Bridge Sandstone Formation (Asturian) of southern Scotland contains two main peaks. One is Early Carboniferous in age (348–318 Ma), and corresponds to the age of igneous activity during the Variscan Orogeny. The other is of late Neoproterozoic to early Cambrian age (693–523 Ma), corresponding to the Cadomian. Together, these two groups comprise 70 % of the zircon population. The presence of these two peaks shows unequivocally that a significant proportion of the sediment was derived from the Variscides of western or central Europe. The zircon population also contains a range of older Proterozoic zircons and a small Devonian component. These could have been derived from the Variscides, but it is possible that some were locally derived through recycling of northerly derived sandstones of Devonian–Carboniferous age. The zircon age data confirm previous suggestions of Variscide sourcing to the Canonbie area, made on the basis of petrographical, heavy mineral and palaeocurrent evidence, and extend the known northward distribution of Variscan-derived Westphalian sediment in the UK.
Variation in harbour seal counts obtained using aerial surveys
Authors: Cunningham Louise , Baxter John M. , Boyd Ian L. 
Published: February 2010

Aerial surveys of harbour seals (Phoca vitulina) are usually carried out to provide an index of population size. This can be normalized, either by design or by post-hoc analysis to reduce the effects that date, time of day, tide and weather might have on the number of seals counted. In order for long-term trends to be determined from these counts it is assumed that the mean number of seals at a particular site does not vary during the survey period, and that the start and duration of the survey window does not vary with location or between years. This study used a combination of repeat land-based and aerial surveys to test the assumption for constancy of counts during the survey period. The study focused on harbour seal abundance at haul-out sites around the Isle of Skye in north-west Scotland. The coefficient of variation in these counts was estimated to be 15%, based on repeat aerial surveys using thermal imaging. Land-based counts were used to examine the effect of covariates on seal numbers using generalized additive modelling. This site-specific model predicted that the current aerial survey window for harbour seals in the UK, which is a three-week period during the moult, is about a week too early and that count variation could be reduced by surveying 1 1/2 hours earlier in the tidal cycle. Furthermore, the pupping period showed even higher (though more variable) abundance of hauled out seals than during the moult.