bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of evaporative light scattering detector in the detection and quantification of enantiomeric mixtures by HPLC
Authors: Zhang Tong , Nguyen Dung , Franco Pilar 
Published: May 2006

AbstractRoutinely used in our laboratories at analytical scale, an evaporative light scattering detector (ELSD) has proved to be versatile in the detection of enantiomeric resolution using chiral stationary phases by HPLC. Though this kind of detector has been widely used in various domains, its application in enantiomeric resolution has not been discussed in the literature and is found to have very specific features especially in the quantitative perspective. In contrast with the UV detection, the peak area from ELSD for both enantiomers of a racemic mixture may not be the same. This complicates the assessment of the enantiomeric purity of unknown samples. This current work deals with some practical aspects in the detection of enantiomers and in accurate quantitative determination of enantiomeric purity by ELSD. Effects of analyte nature (more precisely molecular weight and volatility), peak shape and peak shape difference between enantiomers on the quantitative integration by ELSD are discussed in connection with the UV‐detection results. The calibration for quantitative enantiomeric analysis and its effectiveness are demonstrated.
Dynamic HPLC on chiral stationary phases: A powerful tool for the investigation of stereomutation processes
Authors: D'Acquarica Ilaria , Gasparrini Francesco , Pierini Marco , Villani Claudio , Zappia Giovanni 
Published: May 2006

AbstractDynamic HPLC on enantioselective stationary phases has become a well‐established technique to investigate chiral molecules with internal motions that result in stereoinversion and occur on the time scale of the separation process. Kinetic parameters for the on‐column interconversion phenomena can be extracted from experimental peak profiles by computer simulation or by direct calculation methods. The technique has been used in a wide range of temperatures and is complementary in scope to dynamic NMR spectroscopy.
Trefftz, collocation, and other boundary methods—A comparison
Authors: Li Zi‐Cai , Lu Tzon‐Tzer , Huang Hung‐Tsai , Cheng Alexander H.‐D. 
Published: May 2006

AbstractIn this article we survey the Trefftz method (TM), the collocation method (CM), and the collocation Trefftz method (CTM). We also review the coupling techniques for the interzonal conditions, which include the indirect Trefftz method, the original Trefftz method, the penalty plus hybrid Trefftz method, and the direct Trefftz method. Other boundary methods are also briefly described. Key issues in these algorithms, including the error analysis, are addressed. New numerical results are reported. Comparisons among TMs and other numerical methods are made. It is concluded that the CTM is the simplest algorithm and provides the most accurate solution with the best numerical stability. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Photoinduced birefringence in blends of a polyurethane bearing azobenzene moieties and a poly(amide–imide)
Authors: Ceridório Lucinéia , Cardoso Marcos R , Pavinatto Felippe , Carvalho Antonio JF , Mendonça Cleber R , Balogh Débora T 
Published: May 2006

AbstractA polyurethane (MDI‐DR19Cl) bearing azobenzene moieties was prepared by condensation of 4,4′‐diphenylmethylenediisocyanate and an azobenzene compound, 2‐chloro‐4‐nitro‐4′‐[bis‐(2‐hydroxyethyl)]amine‐azobenzene (DR19Cl). Blends of MDI‐DR19Cl and a poly(amide‐imide) were prepared and characterized by UV‐visible and Fourier transform infrared spectroscopy and by DSC. The purpose of using the blends was to overcome the lack of stability of cast films of pure MDI‐DR19Cl, which tend to crack on storage under ambient conditions. This was successfully achieved and, depending on blend proportions, flexible self‐standing films could be prepared after thermal treatment. Optical storage experiments performed with the blends and pure MDI‐DR19Cl cast films showed a decrease in the remnant values of photoinduced birefringence in the blends (60 % for the blend with 5 wt% MDI‐DR19Cl) compared to pure MDI‐DR19Cl (75%), but, taking into account the low content of MDI‐DR19Cl used, the results obtained are probably sufficient to show the viability of these blends in optical storage applications. Copyright © 2006 Society of Chemical Industry
Circular dichroism spectrum of [Co(en)3]3+ in water: A discrete solvent reaction field study
Authors: Jensen L. , Swart Marcel , van Duijnen Piet Th. , Autschbach J. 
Published: May 2006

AbstractIn this work we investigate the circular dichroism (CD) spectrum of [Co(en)3]3+ in water, using the discrete solvent reaction field (DRF) model. The DRF model is a polarizable quantum mechanics/molecular mechanics (QM/MM) model. The implementation of the DRF model for CD spectra calculations based on time‐dependent density functional theory (TDDFT) is presented. The combination of DRF with TDDFT allows for a computationally attractive solution for calculating chirooptical properties of molecules in solution when explicit solvent structures are of interest. Using a mixed coarse/fine‐grained parallel computation, we show that average CD spectra from snapshots of the solvent structure can be obtained routinely. Classical polarizable molecular dynamics (MD) simulations have been used to obtain the solvent structure around the [Co(en)3]3+ (en = ethyldiamine) solute. We show that the final spectrum converges quickly with respect to the number of configurations. The DRF results were compared with results obtained from the much simpler conductor‐like screening model (COSMO). Both models predicted similar blue shifts of the CD bands, but none of the models is in perfect agreement with the experiments. For instance, the calculated intensities are larger than what is found experimentally if reasonable empirical line width parameters are applied. From the DRF computations, we further show that almost all the solvent effects arise from ground‐state solvation. Thus, ignoring the dynamic solvent response is a good approximation for a system like [Co(en)3]3+, where the solute is highly charged and the solvent is very polar. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Glasdach Mensa und Rektorat der Technischen Universität Dresden
Authors: Zschippang Sven , Wies Wolfgang , Weller Bernhard , Schadow Thomas 
Published: May 2006

AbstractAn der Technischen Universität Dresden entstand im Zuge der Modernisierung der Mensa und des Rektorats ein Glasdach eigener Prägung. Entwurf und Planung des Dachtragwerks als ungerichtete Konstruktion mit Haupt‐ und Nebenträgern aus Verbund‐Sicherheitsglas werden ausführlich dargestellt. Beschrieben werden auch die durchgeführten Bauteilprüfungen zur Erlangung der Zustimmung im Einzelfall für die Konstruktion. Weitere Schwerpunkte des Beitrags sind die Herstellung, die Produktionsüberwachung und die Montage der Glasdachkonstruktion. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weitgespannte gläserne Fassaden
Authors: Burmeister Albrecht , Eitel Lutz , Reitinger Reiner 
Published: May 2006

AbstractThermalbäder erfordern nicht nur ein sehr ausgeklügeltes Konzept und einen optimierten Betrieb, um wirtschaftlich arbeiten zu können, sie erfordern auch eine Gestaltung bzw. technische Details, die für den Besucher eine angenehme Umgebung schaffen. Diese konstruktive Herausforderung wurde am Beispiel der Therme Bad Wörishofen mit Hilfe weitgespannter Fassaden und sorgfältig gestalteter Details gelöst. Um das filigrane Erscheinungsbild zu realisieren, wurden zutreffende Windlasten im Windkanal ermittelt und fortschrittliche Bemessungsstrategien angewandt.Architektonisch anspruchsvolle Lösungen mit der hier vorgestellten Funktionalität und in den angesprochenen Dimensionen erfordern das zielorientierte und konstruktive Zusammenwirken aller Beteiligten. Auch in dieser Hinsicht gilt dem Architekten, Herrn Josef Wund , unser besonderer Dank. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fügen und Verbinden mit UV‐ und lichthärtenden Acrylaten
Authors: Weller Bernhard , Prautzsch Volker , Tasche Silke , Vogt Iris , Jansen Irene 
Published: May 2006

AbstractGeklebte Verbindungen für den Einsatz bei Glaskonstruktionen im Bauwesen sind zur Zeit überwiegend auf die Anwendung von Silikonen beschränkt. Dabei bieten alternative Klebstoffe viele Vorteile. Neben höherer Festigkeit mit teilweise deutlich geringeren Klebstoffdicken sind volltransparente und eingefärbte Klebfugen möglich. Erforderlich für die verbreitete Ausführung von Glasklebungen im Bauwesen ist die Berechenbarkeit des Systems.In einem laufenden Forschungsverbundprojekt werden transparente höherfeste Klebstoffsysteme, deren Eignung für baupraktische Anwendungen nicht beschrieben werden kann, gezielt auf ihre Anwendbarkeit in Glaskonstruktionen untersucht. Typische Konstruktionen im Glasbau, die transparente, elastische und alterungsbeständige Klebungen erfordern, werden erschlossen. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doppler echocardiographic and electrocardiographic atrioventricular time intervals in newborn infants: evaluation of techniques for surveillance of fetuses at risk for congenital heart block
Authors: Bergman G. , Jacobsson L.‐A. , Wahren‐Herlenius M. , Sonesson S.‐E. 
Published: May 2006

AbstractObjectiveTo evaluate one novel and two previously reported Doppler flow velocimetric techniques to estimate atrioventricular (AV) time intervals, suggested to be useful for early identification of fetuses at risk for congenital heart block.MethodsIn 22 newborn infants, Doppler tracings were obtained from the mitral valve/aortic outflow and the superior vena cava/ascending aorta, as an ECG was recorded simultaneously. AV time intervals were measured using the onsets of the mitral A‐wave/aortic outflow (MV‐Ao), superior vena cava a‐wave/aortic flow (SVC‐Ao), and mitral A‐wave/mitral valve closure (MV) as indirect markers of electrical atrial/ventricular activation.ResultsClose positive linear relationships to the electrocardiographic PR interval were demonstrated for the MV‐Ao (r = 0.82, Sy/x = 7.4 ms), SVC‐Ao (r = 0.85, Sy/x = 6.8 ms), and MV (r = 0.92, Sy/x = 3.8 ms) approaches. Both techniques using the aortic flow to indicate ventricular activation overestimated the PR interval: the MV‐Ao by + 32 ± 7.7 ms (mean ± SD) and the SVC‐Ao approach by + 22 ± 7.0 ms. The new MV approach using mitral closure for the same purpose did not overestimate the PR interval, but there was a trend towards underestimation of the PR intervals as time intervals increased.ConclusionsWhen systematic differences between echocardiographic and electrocardiographic AV time intervals are compensated for, all three techniques are useful to get indirect estimates of the PR interval. As MV recordings only need insonation of a single valve, and are thus easier to obtain, this technique may be of value as a first screening method to identify fetuses in need for further surveillance. In cases with AV time prolongation the SVC‐Ao method seems superior. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
The examiner's ultrasound experience has a significant impact on the detection rate of congenital heart defects at the second‐trimester fetal examination
Authors: Tegnander E. , Eik‐Nes S. H. 
Published: May 2006

AbstractObjectivesTo determine whether training and experience in performing ultrasound examinations are factors that influence the prenatal detection of congenital heart defects (CHDs) in a non‐selected population, in order to evaluate and improve the current training program.MethodsAll pregnant women who received a routine second‐trimester ultrasound scan by a sonographer/midwife and delivered at our hospital between February 1991 and December 2001 were registered prospectively. Less experienced sonographer/midwives who had performed between 200 and 2000 routine examinations were compared with experienced sonographer/midwives who had carried out more than 2000 examinations. During the first 5 years of the study the heart structures obtained were registered in detail.ResultsOf 29 035 fetuses, 35/82 (43%) major CHDs were prenatally detected at the routine examination. The experienced sonographer/midwives obtained both the four‐chamber view and the great arteries in 75%; the figure for the less experienced sonographer/midwives was 36% (P < 0.001). The differences in detecting major heart defects were 22/42 (52%) and 13/40 (32.5%), isolated CHDs 8/18 (44%) and 6/22 (27%) and CHDs with associated malformations 14/24 (58%) and 7/18 (39%), respectively. In both groups some CHDs with an abnormal four‐chamber view were missed, although the experienced sonographer/midwives recognized significantly more of the abnormal views than did the less experienced sonographer/midwives (P = 0.002).ConclusionsExperience has a significant impact on the examination of the fetal heart and the prenatal detection rate of major CHDs. To avoid a relatively long learning curve, ultrasound education needs to intensify the teaching of the basic four‐chamber view. The great arteries should be included after additional training. Those basic views of the fetal heart must be mastered before new views and advanced technology are added to the fetal heart examination. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
MODULI CURVES OF SUPERSINGULAR K3 SURFACES IN CHARACTERISTIC 2 WITH ARTIN INVARIANT 2
Authors: Shimada Ichiro 
Published: May 2006

AbstractWe construct moduli curves of polarized supersingular K3 surfaces in characteristic 2 with Artin invariant 2. As an application, we detect a ‘jump’ phenomenon in a family of automorphism groups of supersingular K3 surfaces with a constant Néron–Severi lattice.
PRESENTATION BY BOREL SUBALGEBRAS AND CHEVALLEY GENERATORS FOR QUANTUM ENVELOPING ALGEBRAS
Authors: Gavarini Fabio 
Published: May 2006

AbstractWe provide an alternative approach to the Faddeev–Reshetikhin–Takhtajan presentation of the quantum group $\uqg$, with $L$-operators as generators and relations ruled by an $R$-matrix. We look at $\uqg$ as being generated by the quantum Borel subalgebras $U_q(\mathfrak{b}_+)$ and $U_q(\mathfrak{b}_-)$, and use the standard presentation of the latter as quantum function algebras. When $\mathfrak{g}=\mathfrak{gl}_n$, these Borel quantum function algebras are generated by the entries of a triangular $q$-matrix. Thus, eventually, $U_q(\mathfrak{gl}_n)$ is generated by the entries of an upper triangular and a lower triangular $q$-matrix, which share the same diagonal. The same elements generate over $\Bbbk[q,q^{-1}]$ the unrestricted $\Bbbk [q,q^{-1}]$-integral form of $U_q(\mathfrak{gl}_n)$ of De Concini and Procesi, which we present explicitly, together with a neat description of the associated quantum Frobenius morphisms at roots of 1. All this holds, mutatis mutandis, for $\mathfrak{g}=\mathfrak{sl}_n$ too.
NOTE ON THE RATIONAL POINTS OF A PFAFF CURVE
Authors: Pila Jonathan 
Published: May 2006

AbstractLet $X\subset\mathbb{R}^2$ be the graph of a Pfaffian function $f$ in the sense of Khovanskii. Suppose that $X$ is non-algebraic. This note gives an estimate for the number of rational points on $X$ of height less than or equal to $H$; the estimate is uniform in the order and degree of $f$.
AN EXISTENCE THEOREM FOR QUASILINEAR SYSTEMS
Authors: Wang Haiyan 
Published: May 2006

AbstractThis paper deals with the existence of positive radial solutions for the quasilinear system $\text{div}(|\nabla u_i|^{p-2}\nabla u_i)+\lambda f^i(u_1,\dots,u_n)=0$, $|x|\lt1$, $u_i(x)=0$, on $|x|=1$, $i=1,\dots,n$, $p\gt1$, $\lambda>0$, $x\in\mathbb{R}^N$. The $f^i$, $i=1,\dots,n$, are continuous and non-negative functions. Let $\bm{u}=(u_1,\dots,u_n)$, $\|\bm{u}\|=\sum_{i=1}^n|u_i|$,$$ f_0^i=\lim_{\|\bm{u}\|\to0}\frac{f^i(\bm{u})}{\|\bm{u}\|^{p-1}}, $$$i=1,\dots,n$, $\bm{f}=(f^1,\dots,f^n)$, $\bm{f}_0=\sum_{i=1}^nf_0^i$. We prove that the problem has a positive solution for sufficiently small $\lambda>0$ if $\bm{f}_0=\infty$. Our methods employ a fixed-point theorem in a cone.
THE ROLE OF FUNNELS AND PUNCTURES IN THE GROMOV HYPERBOLICITY OF RIEMANN SURFACES
Authors: Portilla Ana , Rodríguez José M. , Tourís Eva 
Published: May 2006

AbstractWe prove results on geodesic metric spaces which guarantee that some spaces are not hyperbolic in the Gromov sense. We use these theorems in order to study the hyperbolicity of Riemann surfaces. We obtain a criterion on the genus of a surface which implies non-hyperbolicity. We also include a characterization of the hyperbolicity of a Riemann surface $S^*$ obtained by deleting a closed set from one original surface $S$. In the particular case when the closed set is a union of continua and isolated points, the results clarify the role of punctures and funnels (and other more general ends) in the hyperbolicity of Riemann surfaces.
!THE $\aleph_1$-PRODUCT OF DG-INJECTIVE COMPLEXES
Authors: Enochs Edgar E. , Iacob Alina 
Published: May 2006

AbstractGiven a left Noetherian ring $R$, we give a necessary and sufficient condition in order that a complex of $R$-modules be DG-injective. Using this result we prove that if $(K_i)_{i\in I}$ is a family of DG-injective complexes of left $R$-modules and $K$ is the $\aleph_1$-product of $(K_i)_{i\in I}$ (i.e. $K\subset\prod_{i\in I}K_i$ is such that, for each $n$, $K^n\subset\prod_{i\in I}K_i^n$ consists of all $(x_i)_{i\in I}$ such that $\{i\mid x_i\neq0\}$ is at most countable), then $K$ is DG-injective.
Poly(ADP-ribose) glycohydrolase silencing protects against H2O2-induced cell death
Authors: Blenn Christian , Althaus Felix R. , Malanga Maria 
Published: May 2006

PAR [poly(ADP-ribose)] is a structural and regulatory component of multiprotein complexes in eukaryotic cells. PAR catabolism is accelerated under genotoxic stress conditions and this is largely attributable to the activity of a PARG (PAR glycohydrolase). To overcome the early embryonic lethality of parg-knockout mice and gain more insights into the biological functions of PARG, we used an RNA interference approach. We found that as little as 10% of PARG protein is sufficient to ensure basic cellular functions: PARG-silenced murine and human cells proliferated normally through several subculturing rounds and they were able to repair DNA damage induced by sublethal doses of H2O2. However, cell survival following treatment with higher concentrations of H2O2 (0.05–1 mM) was increased. In fact, PARG-silenced cells were more resistant than their wild-type counterparts to oxidant-induced apoptosis while exhibiting delayed PAR degradation and transient accumulation of ADP-ribose polymers longer than 15-mers at early stages of drug treatment. No difference was observed in response to the DNA alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine, suggesting a specific involvement of PARG in the cellular response to oxidative DNA damage.
Cutaneous extrarenal rhabdoid tumor with myogenic differentiation
Authors: Petitt Matthew , Doeden Katherine , Harris Alexis , Bocklage Thèrése 
Published: May 2006

Background:  The rhabdoid phenotype is characterized by large epithelioid cells with abundant eosinophilic cytoplasm and paranuclear inclusions of intermediate filaments. Although originally described in tumors from pediatric kidneys, the rhabdoid phenotype has since been described in a variety of patient ages and extrarenal sites. Extraordinarily, the rhabdoid phenotype has emerged in cutaneous neoplasms, either as a pure extrarenal rhabdoid tumor or a composite phenotype coupled with another malignancy. Regardless of the clinical setting, the rhabdoid phenotype is uniformly associated with aggressive biological behavior. We report the findings from a rare and very aggressive primary extrarenal rhabdoid tumor of the skin with myogenic differentiation.Case report:  A 53‐year‐old woman presented with an ulcerated nodule on her right medial calf and ipsilateral inguinal lymphadenopathy. Histological examination of the skin nodule as well as cytologic examination of a lymph node disclosed the characteristic rhabdoid phenotype. Electron microscopy demonstrated paranuclear globules of intermediate filaments; special stains suggested an underlying myogenic histogenesis. The patient was aggressively treated with chemotherapy but ultimately died of her disease 8 months after presentation.Conclusions:  The rhabdoid phenotype is rarely seen in cutaneous neoplasms, but when present, portends a poor prognosis adding particular importance to its recognition.
Facial thermography is a sensitive tool to determine antihistaminic activity: comparison of levocetirizine and fexofenadine
Authors: Larbig Michael , Burtin Bernard , Martin Laurent , Stamm Holger , Luettig Birgit , Hohlfeld Jens M. , Krug Norbert 
Published: May 2006

AimsTo assess the antihistaminic activity of levocetirizine and fexofenadine 2 h and 24 h after drug administration using facial thermography and to compare the results with those using well‐established parameters of antihistaminic activity in the nose and skin.MethodsThis was a randomized, double‐blind, three‐treatment, three‐period, single‐dose, cross‐over study in healthy males taking levocetirizine 5 mg, fexofenadine 120 mg or placebo. The primary endpoint was nasal skin temperature after nasal histamine challenge recorded for 20 min at 2 and 24 h after drug intake. The secondary endpoints were nasal symptoms and a histamine skin prick test.ResultsThirty subjects were randomized. At 2 h after drug intake the inhibition of the nasal temperature increase from baseline was not significantly different between levocetirizine and fexofenadine. At 24 h it was significantly more pronounced after levocetirizine than fexofenadine (difference: least‐squares mean: −0.13 °C; P ≤ 0.024, 95% CI −0.24, −0.02). Both drugs significantly reduced (P ≤ 0.001) the mean temperature increase from baseline compared with placebo at 2 and 24 h (least‐squares mean increase and (95% CI): levocetirizine, −0.28 °C (−0.42, −0.14) and −0.32 °C (−0.43, −0.21); fexofenadine −0.35 °C (−0.49, −0.21) and −0.19 °C (−0.30, −0.08), respectively). Results of nasal symptom score and wheal and flare were consistent with the thermography results.ConclusionsFacial thermography is an objective, non‐invasive and sensitive method to study antihistaminic activity at the nose level. Levocetirizine and fexofenadine demonstrate the same activity at 2 h after drug intake, but levocetirizine has a more sustained activity at 24 h.
Deep water waves in lakes
Authors: SMITH I. R. , SINCLAIR I. J. 
Published: May 2006

SummaryThe properties of waves on a lake surface and the influence of water depth on these properties are discussed.The method, derived by the Beach Erosion Board, of predicting wave characteristics if the wind speed and fetch are known is outlined and the validity of the method in Loch Leven, Scotland, is confirmed.This prediction technique is then combined with the equations of classical hydrodynamics to form a method of assessing the nature and extent of wave action in lakes without direct measurement. The value of the ratio of the wave‐mixed volume to the total lake volume as a meausre of hydraulic conditions in lakes is suggested.