bluuebunny/crossref_metadata_2025 huggingface dataset:
Self‐Assembly of Heteroarm Star Copolymers – A Monte Carlo Study
Authors: Havránková Jitka , Limpouchová Zuzana , Štěpánek Miroslav , Procházka Karel
Published: May 2007

Dynamic lattice Monte Carlo simulations on a simple cubic lattice were used to study the association behavior of heteroarm star copolymers with two types of chemically different arms (miktoarm star). The effect of architecture and composition (number and length of arms) on self‐assembly was investigated. Simulations revealed substantial differences between associates formed by linear diblock copolymers and by star copolymers. It was also observed that the length of arms considerably influences the association behavior. Apart from the structural characteristics of the whole associate, the properties of individual stars in associates were also studied. These results provide detailed information on the inner structure of associates.

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Monte Carlo Simulation of Polymer Reactions at Interfaces
Authors: John Andreas , Nagel Jürgen , Heinrich Gert
Published: May 2007

Adhesion of immiscible polymers during two‐component injection moulding may be improved by transreactions of properly functionalised components. We performed MC simulations based on the three‐dimensional coarse‐grained bond fluctuation model (BFM) including a thermal interaction potential in $r \leq \sqrt{6}$ with energy $\varepsilon = \pm 0.1\,k_{\rm B} T$ to characterise the behaviour of several selected types of chemical reactions, which are governed by activation energies of EA = 0, 1, 3 and 5 kBT. The consumption of reactive monomers for all the reactions in the time interval below the Rouse time τR exhibits a typical crossover from a kinetic‐controlled to a diffusion‐controlled behaviour and can be described by a bimolecular kinetic ansatz.

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Modelling the Influence of Nanoparticles in the Phase Behaviour of an Epoxy/Polystyrene Mixture, 2
Authors: Figueruelo Juan E. , Gómez Clara M. , Monzó Isidro S. , Abad Concepción , Campos Agustín
Published: May 2007

The influences of nanoparticle size and concentration on the thermodynamic behaviour of epoxy/polystyrene blends are evaluated in the framework of Ginzburg's simple analytical theory. Two approaches have been employed: NPEPO (for particles coated with epoxy groups) and NPFEN (for particles coated with phenyl groups). Using NPEPO, the particles are found to prefer the phase richer in epoxy, whereas the opposite occurs for NPFEN. The particles size significantly influences blend compatibility. When the particle radius Rp is about the same size as the radius of gyration Rg of PS, the compatibility of blends increases with particle concentration, whereas for Rp > Rg, higher particle concentrations do not clearly stabilize the polymeric blends.

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Polymer Distribution Change During Irreversible Depolymerization by Chain‐End Scission
Authors: Tobita Hidetaka
Published: May 2007

The change in polymer distribution during depolymerization in which monomer molecules are severed one by one from the chain ends, is considered. Assuming irreversible depolymerization and equal reactivity of all the chain ends, a general formula to calculate the MWD is proposed. After the removal of monomers severed from the chains, the MWDs of depolymerized polymers always approach the most probable distribution whose PDI is practically equal to 2. It may appear to be counterintuitive, but the average MWs of polymers may increase during chain scission when the initial distribution is broader than the most probable (PDI  >  2). The interpretation of the MWD data of polymers during depolymerization, such as those obtained by GPC, are not straightforward especially for the initial broad MWDs.

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A Review of Modeling of Diffusion Controlled Polymerization Reactions
Authors: Achilias Dimitris S.
Published: May 2007

A plethora of models have been developed quantifying the effect of diffusion‐controlled phenomena on polymerization reactions. The most prominent approaches are reviewed here, including innovative ones that have emerged over the last decade. Free‐radical and step‐growth polymerizations are considered in a way to show that similar models have been used in both mechanisms. In free‐radical polymerization the models proposed are subdivided according to their theoretical background into four categories: (i) based on a Fickian description of reactant diffusion; (ii) free‐volume theory based; (iii) chain‐length dependent; and, (iv) empirical. The reversible addition‐fragmentation technique is discussed, together with two industrially important case‐studies, solid state polycondensation and epoxy‐amine curing.

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Macromol. Theory Simul. 4/2007
Authors: Sarvestani Alireza S. , Jabbari Esmaiel
Published: May 2007

Cover: The picture on the cover shows the equilibrium configuration of a partly adsorbed polymer chain on the surface of an adhesive particle. The adsorption is assumed to be reversible and the adsorbed polymer detaches from the surface after certain residence time, determined by the corresponding energy barriers. Further details can be found in the article by A. S. Sarvestani and E. Jabbari* on page 378.
Acute vibration reduces Aβ nerve fiber sensitivity and alters gene expression in the ventral tail nerves of rats
Authors: Krajnak Kristine , Waugh Stacey , Wirth Oliver , Kashon Michael L.
Published: May 2007

Long‐term occupational exposure to hand–arm vibration can result in a permanent reduction in tactile sensitivity in exposed fingers and hands. Little is known about how vibration causes this reduction in sensitivity, and currently no testing procedures have been developed to monitor changes in sensory perception during ongoing exposures. We used a rat‐tail model of hand–arm vibration syndrome (HAVS) to determine whether changes in sensory nerve function could be detected after acute exposure to vibration. Nerve function was assessed using the current perception threshold (CPT) method. We also determined whether changes in nerve function were associated with changes in gene transcription. Our results demonstrate that the CPT method can be used to assess sensory nerve function repeatedly in rats and can detect transient decreases in the sensitivity of Aβ nerve fibers caused by acute exposure to vibration. This decrease in Aβ fiber sensitivity was associated with a reduction in expression of nitric oxide synthase‐1, and a modest increase in calcitonin gene–related peptide transcript levels in tail nerves 24 h after vibration exposure. These transient changes in sensory perception and transcript levels induced by acute vibration exposure may be indicators of more prolonged changes in peripheral nerve physiology. Muscle Nerve, 2007
The Private sector in state service delivery: Examples of innovative practices
Authors: Hatry Harry P. , Skidmore Felicity
Published: May 2007

Tax‐limitation referenda and a presidential administration bullish on privatization have resulted in widespread use of the private sector to deliver state and local services. For years the stragglers of the privatization movement, states have more recently taken responsible and innovative steps toward involving the private sector in the areas of parks and recreation and human services.
Surface plasmon enhanced bright light emission from InGaN/GaN
Authors: Okamoto Koichi , Niki Isamu , Shvartser Alexander , Maltezos George , Narukawa Yukio , Mukai Takashi , Kawakami Yoichi , Scherer Axel
Published: May 2007

Surface plasmon (SP) coupling technique was used to enhance blue and green light emissions from InGaN/GaN quantum wells (QWs). Large enhancement of photoluminescence (PL) of both blue and green emissions was observed with silver coated samples, whereas the enhancements were not so effective for the gold coated samples. We could obtain well enhanced green emission by tuning the matching condition of QW‐SP coupling with nano‐grating structures at gold layers. This method should be useful to design even more efficient structures and to fabricate super bright light emitting devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid model predictive control approach to the direct torque control problem of induction motors
Authors: Papafotiou Georgios , Geyer Tobias , Morari Manfred
Published: May 2007

Direct torque control (DTC) is a state‐of‐the‐art control methodology for electric motor drives which features favourable control performance and implementation properties. In DTC, the core of the control system is the inverter switching table, and any efforts to enhance the system's performance aim at improving its design. This issue is addressed in this paper, where we propose a new design procedure for the DTC problem. The DTC drive, comprising a two‐ or three‐level dc‐link inverter driving a three‐phase induction motor, is modelled in the hybrid mixed logical dynamical (MLD) framework, and a constrained finite‐time optimal control problem is set up and solved over a receding horizon using model predictive control (MPC). Simulation results are provided and compared to the current industrial standard demonstrating the potential for notable performance improvements. Copyright © 2007 John Wiley & Sons, Ltd.
Non‐convex optimization and robustness in realtime model predictive control
Authors: DeHaan Darryl , Guay Martin
Published: May 2007

Recent works in the nonlinear model predictive control (MPC) literature have presented ‘realtime’ optimization approaches based upon incremental updating of input parameters using local descent directions of the cost functional. The main downside to these methods is their strong dependence upon the values used to initialize the input parameters. In this note we study the robustness issues associated with non‐local search methods in continuous‐time MPC, and demonstrate a framework for robustly incorporating these approaches in a realtime setting. Copyright © 2007 John Wiley & Sons, Ltd.
A functional limit theorem for random graphs with applications to subgraph count statistics
Authors: Janson Svante
Published: May 2007

We consider a random graph that evolves in time by adding new edges at random times (different edges being added at independent and identically distributed times). A functional limit theorem is proved for a class of statistics of the random graph, considered as stochastic processes. the proof is based on a martingale convergence theorem. the evolving random graph allows us to study both the random graph model Kn, p, by fixing attention to a fixed time, and the model Kn, N, by studying it at the random time it contains exactly N edges. in particular, we obtain the asymptotic distribution as n → ∞ of the number of subgraphs isomorphic to a given graph G, both for Kn, p (p fixed) and Kn, N (N/(n2)→ p). the results are strikingly different; both models yield asymptotically normal distributions, but the variances grow as different powers of n (the variance grows slower for Kn, N; the powers of n usually differ by 1, but sometimes by 3). We also study the number of induced subgraphs of a given type and obtain similar, but more complicated, results. in some exceptional cases, the limit distribution is not normal.
Probabilistic analysis of a parallel algorithm for finding maximal independent sets
Authors: Calkin Neil , Frieze Alan
Published: May 2007

We consider a natural parallel version of the classical greedy algorithm for finding a maximal independent set in a graph. This version was studied in Coppersmith, Raghavan, and Tompa and they conjecture there that its expected running time on random graphs of arbitrary edge density of O (log n). We prove that conjecture.
On the discrepancy of 3 permutations
Authors: Bohus Géza
Published: May 2007

Consider different orderings of an n‐element set and the hypergraph consisting of the intervals of these orderings. A conjecture of J. Beck states that in the case of three orderings this hypergraph has bounded discrepancy. We show that for any constant number of orderings the discrepancy is O(log n). the proof also gives an efficient algorithm to determine such a coloring.
Poisson approximation for large deviations
Authors: Janson Svante
Published: May 2007

Upper and lower bounds are given for P(S ≤ k), 0 ≤ k ≤ ES, where S is a sum of indicator variables with a special structure, which appears, for example, in subgraph counts in random graphs. in typical cases, these bounds are close to the corresponding probabilities for a Poisson distribution with the same mean as S. There are no corresponding general bounds for P(S ≥ k), k > ES, but some partial results are given.
A correlation inequality and a poisson limit theorem for nonoverlapping balanced subgraphs of a random graph
Authors: Suen W. C. Stephen
Published: May 2007

We consider non‐overlapping subgraphs of fixed order in the random graph Kn, p(n). Fix a strictly strongly balanced graph G. A subgraph of Kn, p(n) isomorphic to G is called a G‐subgraph. Let Xn be the number of G‐subgraphs of Kn, p(n) vertex disjoint to all other G‐subgraphs. We show that if E[Xn]→∞ as n→, then Xn/E[Xn] converges to 1 in probability. Also, if E[Xn]→c as n→∞, then Xn satisfies a Poisson limit theorem. the Poisson limit theorem is shown using a correlation inequality similar to those appeared in Janson, Łuczak, and Ruciñski[8] and Boppana and Spencer [4].
Matchings in random spanning subgraphs of cubelike graphs
Authors: Kostochka Alexandr V.
Published: May 2007

A question about the evolution of random spanning subgraphs Gp of bipartite regular so called cubelike graphs G is considered. It is shown that for Gp of any large enough cubelike graph G the threshold to have a 1‐factor is the same as the threshold to have no isolated vertices. This generalizes a conjecture of K. Weber.
Quasi‐random classes of hypergraphs
Authors: Chung Fan R. K.
Published: May 2007

We investigate the relations among a number of different graph properties for k‐uniformhypergraphs, which are shared by random hypergraphs. Various graph properties form equivalence classes which in turn constitute a natural hierarchy. The analogues for binary functions on k‐tuples and for hypergraphs with small density are also considered. Several classes are related to communication complexity and expander graphs.
Small cliques in random graphs
Authors: Barbour A. D. , Janson Svante , Karoński Michal , Ruciński Andrzej
Published: May 2007

For d ≥ 1, a d‐clique in a graph G is a complete d‐vertex subgraph not contained in any larger complete subgraph of G. We investigate the limit distribution of the number of d‐cliques in the binomial random graph G(n, p), p = p(n), n→∞.
A note on bipartite subgraphs of triangle‐free graphs
Authors: Shearer James B.
Published: May 2007

Let G be a triangle‐free graph on n points with m edges and vertex degrees d1, d2,…, dn. Let k be the maximum number of edges in a bipartite subgraph of G. In this note we show that k ⩾ m/2 + Σ √di. It follows as a corollary that k ⩾ m/2 + cm3/4.
Random recursive forests
Authors: Balińska Krystyna T. , Quintas Louis V. , Szymański Jerzy
Published: May 2007

A random recursive forest is defined as a union of random recursive trees. We find the expected number of trees in the uniform random recursive forest as well as the number of vertices of given degree, the maximum degree, the height of vertices, the order of branches, the root of the component containing a given vertex, and the last root of such forests. © 1994 John Wiley & Sons, Inc.
The maximum degree in a random tree and related problems
Authors: Carr Robin , Goh William M. Y. , Schmutz Eric
Published: May 2007

Meir and Moon studied the distribution of the maximum degree for simply generated families of trees. We have sharper results for the special case of labelled trees. © 1994 John Wiley & Sons, Inc.
Note on independent sets in steiner systems
Authors: Rödl Vojtěch , Šinajová Edita
Published: May 2007

A partial Steiner (n, k, l)‐system or briefly (n, k, l)‐system is a pair (V, S), where V is an n‐set and S is a collection of k‐subsets of V, such that every l‐subset of V is contained in at most one k‐subset of S. A subset X ⊂ V is called independent if [X]k ∩ S = 0. The size of the largest independent set in S is denoted by α(S). Define

The purpose of this note is to prove that for every k, l, k > l

holds, where c, d are positive constants depending on k and l only.
Ansätze zur Lösung der Grundgleichungen der Elastizitätstheorie
Authors: Marguerr K.
Published: May 2007

In den letzten Jahren sind zahlreiche Probleme der Elastizitätstheorie in 2 und 3 Dimensionen gelöst worden. Die Lösungsansätze, scheinbar ganz verschiedener Natur, erweisen sich bei näherem Zusehen als miteinander nahe verwandt: letzten Endes versucht man die Lösung aus Potentialfunktionen aufzubauen. Die vorliegende Arbeit stellt die Beziehungen zwischen einer großen Zahl solcher Ansätze her, und ergänzt sie durch einen didaktisch naheliegenden neuen. Ein Anhang gibt die wichtigsten Vektor‐ und Tensor‐Rechenregenl.
Inversion of a perfectly elastic spherical shell
Authors: Ericksen J. L.
Published: May 2007

The problem of inversion of a spherical shell which is made of an incompressible, perfectly elastic material is solved in full generality. It is shown that, if the strain energy is of the form assumed in the Mooney‐Rivlin theory for rubber, then the surfaces of the deformed shell may be left free of surface tractions.
Ein praktisches Verfahren zur Lösung biquadratischer Gleichungen mit nur komplexen Wurzeln
Authors: Ludwig Rudolf
Published: May 2007

Für die biquadratische Gleichung erhält man für komplexe Wurzeln durch Trennung von Real‐ und Imaginärteil zwei reelle Gleichungen, deren Resultante die Realteile als Wurzeln hat. Es wird ein praktisches Rechenverfahren angegeben zur iterativen Ermittlung von Näherungswerten der reellen Wurzeln dieser Resultante, bei dem man nur das vollständige, reelle Horner‐Schema der gegebenen Gleichung benötigt. Die zugehörigen Imaginärteile sind einfach auszurechnen.
The Film Combustion of Liquid Fuel
Authors: Emmons H. W.
Published: May 2007

Für Tröpfchen, die größer als, sagen wir, 10−1 Zoll sind, entfernen Wärmeleitungs‐ und Diffusionsprozesse die chemische Reaktionszone weit genug vom Tröpfchen dorthin, wo sie für die Effekte des Tröpfchens selbst weniger sensibel ist, und daher die Verbrennungsgeschwindigkeit von den Wärmeleitungs‐ und Massenprozessen selbst gesteuert wird. Dieses Problem wird in dieser Arbeit untersucht und teilweise gelöst.
Die dicke Platte mit nichtlinearer Spannungsverteilung
Authors: Koppe Eberhard
Published: May 2007

Am Beispiel der dicken Platte mit nichtlinearer Spannungsverteilung wird dargelegt, wie man ausgehend von den Invarianten des Problems einen bequemen und allgemeinen Weg zu strengen Lösungen findet. An den Seitenrändern der Platte können dabei unabhängig voneinander Normal‐ und Tangentialkräfte, Randscherkräfte, Randbiege‐ und Randdrillmomente vorgeschrieben werden. Für zwei sehr allgemeine und praktisch wichtige Klassen von Belastungen werden die Verteilungsfunktionen für die Verschiebungen über die Plattendicke ausgerechnet.
Biegungsschwingungen in zusammengesetzten Stäben
Authors: Vodička Václav
Published: May 2007

Mathematische Untersuchungen von Biegeungsschwingungen gleichförmiger zusammengesetzter Stäbe führt zu recht komplizierten Rechnungen. Eine Vorstellung davon gibt der folgende Aufsatz.
Three‐dimensional Boundary Layer Equations
Authors: Sanyal Lakshmi
Published: May 2007

Following Schmidt and Schröder, the three‐dimensional boundary layer equations on a surface have been obtained here in a rigorous manner with a minimum number of hypotheses which have been precisely stated. For this purpose, the parallel system of coordinates is used and the equations of the boundary layer deduced in an elegant form in these coordinates.
Zum Differenzenverfahren bei parabolischen Differentialgleichungen
Authors: Albrecht Julius
Published: May 2007

Diskussion des Differenzenverfahrens bei parabolischen Differentialgleichungen (Wärmeleitungs‐ und Stabschwingungsgleichung): Zusammenhang zwischen Stabilität, Zeitschrittweite und Lage der verwendeten Gitter‐punkte; Genauigkeit (Mehrstellenverfahren); gekrümmte Ränder; Runge‐Kutta‐Prinzip.
Berechnungsergebnisse der radialen Schaufelgitterströmung
Authors: Isay Wolfgang‐Hermann
Published: May 2007

In der vorliegenden im Institut für Angewandte Mathematik der Deutschen Akademie der Wissenschaften zu Berlin durchgeführten Arbeit werden numerische Ergebnisse der radialen Schaufelgitterströmung mitgeteilt und diskutiert. Diese Ergebnisse wurden mit Hilfe der vom Verfasser in früheren Arbeiten veröffentlichten Schaufelgittertheorie erhalten.
Praktische Lösung von Eigenwertaufgaben des Hartree‐Fockschen Typs
Authors: Dettmar H.‐K. , Schlüter A.
Published: May 2007

In der vorliegenden Arbeit wird eine numerische Methode zur genäherten Lösung der Schrödingergleichung des quantenmechanischen Mehrkörperproblems der Elektronen einer Atomhülle beschrieben. Das Hauptaugenmerk wird auf die mathematische Durschführung gelegt, während das physikalische Problem in den Hintergrund tritt. Die herangezogenen mathematischen Hilfsmittel sowie die abgeleiteten Formeln sind möglichst allgemein gehalten und unabhängig von den genannten Problemen in § 1 zusammengestellt.
Über ein Warteproblem aus der Vermittlungstechnik
Authors: Störmer Horand
Published: May 2007

Die bekannte, von A. K. Erlang angegebene Verteilung der Wartezeiten, die vor einer zentralen Steuereinrichtung mit konstanter Arbeitszeit T0 auftreten, gilt für den Fall, daß wartende Anrufe in der Reihenfolge ihres Eintreffens abgefertigt werden. In der Praxis ist diese Voraussetzung häufig nicht erfüllt. Die wartenden Anrufe werden vielmehr in einer durch Zufall bestimmten Reihenfolge abgefertigt.

In der folgenden Untersuchung wird zunächst die Verteilung der Wartezeiten bei Abfertigung der wartenden Anrufe nach einer bestimmten Rangordnung (m verschiedene Rangstufen) hergeleitet. Dann wird angenommen, daß jedem Anruf zufallsmäßig eine dieser m Rangstufen (Dringlichkeitsstufen) zugeordnet wird. Für m → ∞ ergibt sich ein einfacher geschlossener Ausdruck für die Verteilungsfunktion der Wartezeiten.
Stresses due to Diametral Forces in Tension on an Eccentric Hole of a Circular Disc
Authors: Gupta D. P.
Published: May 2007

In this paper, the problem of determining stresses in a circular disc with an eccentric circular hole is taken up, when the hole is subjected to two equal and opposite forces in tension along the line of centres, the outer boundary of the disc being unstressed. The solution is determined in bipolar coordinates. From the results thus obtained the stresses on a semi‐infinite plate acted upon by two equal and opposite diametral forces in tension on a circular hole in the plate in the direction of the normal to the straight boundary, the latter being kept free, have been deduced.
Zur Frage der Fehlerabschätzung beim Verfahren der harmonischen Balance
Authors: Sagirow P.
Published: May 2007

Die harmonische Balance liefert uns für die Frequenz und Amplitude einer periodischen Lösung von (1) gewisse Werte ωhund ah. Die Fehler, mit denen diese Näherungswerte behaftet sind, bleiben jedoch unbekannt.

In der vorliegenden Arbeit wird ein Verfahren vorgeschlagen, das in sehr vielen Fällen eine sukzessive Abschätzung des Frequenzfehlers und eine anschließende Abschätzung des Amplitudenfehlers gestattet. Dabei wird festgestellt, daß im allgemeinen schon ein geringer Frequenzfehler einen großen Amplitudenfehler nach sich zieht.

Ein Beispiel wird durchgerechnet.
Some Problems in the Small Deflexions of Clamped Thin Isotropic Plates
Authors: Bassali W. A.
Published: May 2007

Conformal mapping methods are applied to find exact solutions in finite terms for the small deflexions of certain thin clamped curvilinear plates subject to symmetrical loading distributed over the area of a circle or acted by isolated forces or couples at arbitrary or specified points. Plates bounded by the inverses of an ellipse with respect to internal or boundary points are included. Regular curvilinear polygonal plates bounded by n equal and very approximately circular arcs are also considered.
Zur Theorie der diskreten unsymmetrischen Irrfahrt
Authors: Henze E.
Published: May 2007

Für die unsymmetrische Irrfahrt im ebenen Gitter der Punkte mit ganzzahligen Koordinaten werden das Klassifikationsproblem, die Übergangswahrscheinlichkeit mit ihrer erzeugenden Funktion, das Visitenproblem und die wichtigsten Absorptionswahrscheinlichkeiten behandelt. Als Gebiete werden dabei die unbegrenzte Ebene und die obere Halbebene mit der Abszissenachse als punktweise 1‐absorbierender Berandung zugrunde gelegt und die asymptotischen Ausdrücke für verschwindende Maschenweite des Gitters aufgestellt.
The Influence of Tocopherols on the Oxidation Stability of Methyl Esters
Authors: Fröhlich András , Schober Sigurd
Published: May 2007

Tocopherols were found to be the principal natural antioxidants in biodiesel grade fatty acid methyl esters. The stabilising effect of α‐, γ‐ and δ‐ tocopherols from 250 to 2,000 mg/kg was evaluated by thermal and accelerated storage induction times based on rapid viscosity increase, in sunflower (SME), recycled vegetable oil (RVOME), rapeseed (RME) and tallow (TME) methyl esters. Both induction times showed that stabilising effect is of the order of δ‐ > γ‐ > α‐tocopherol, and that the stabilising effect increased with concentration. The correlation between the two induction times however was poor, which is probably due to the fact that the time they correspond to two different stages of oxidation. Tocopherols were found to stabilise methyl esters by reducing the rate of peroxide formation while present. The deactivation rates of tocopherols increased with unsaturation of the particular methyl ester and in the present work they were of the order of SME > RME > RVOME > TME. While α‐tocopherol was found to be a relatively weak antioxidants, both γ‐ and δ‐ tocopherols increased induction times significantly and should be added to methyl esters without natural antioxidants.
Volatile compounds produced during deodorization of soybean oil and their flavor significance
Authors: Kao Jian‐Wen , Hammond Earl G. , White Pamela J.
Published: May 2007

Freshly deodorized soybean oil has a characteristic nutty flavor but often yields no detectable headspace volatiles. The cause of this flavor was investigated by deodorizing soybean oil in an apparatus with a double cold trap that allowed the volatile compounds formed from the initial decomposition of hydroperoxides to be collected separately from those produced during the normal deodorization process. The chief volatile components from the normal deodorization process were hydrocarbons, which contributed little to no odor to the oil. The compounds with the greatest odor were carbonyls, especially heptanal and cis‐4‐heptenal. Although these comonpents should accumulate at some steady‐state concentration in an oil during its deodorization, none seemed to account for the flavor of the deodorized oil. By using a particle detector, it was shown that small particles could be generated in the human mouth that could provide a mechanism to bring oil with nonvolatile flavor components into contact with the olfactory organ. Attempts to separate possible nonvolatile flavors in deodorized oil from triacylglycerides by chromatography on alumina or reaction with 2,4‐dinitrophenylhydrazine were unsuccessful. Possibly, the flavor is caused by the glycerol esters themselves.
Chloramine T with iodine: A new reagent to determine the iodine value of edible oils
Authors: Nagendrappa Giddappa , Raj Urs S. Subramanya , Rajalakshmi S.
Published: May 2007

Chloramine T (N‐chloro‐p‐toluenesulfonamide sodium salt) and iodine (2:1, w/w) in carbon tetrachloride and acetic acid (1:1, vol/vol), referred to as reagent (I) was found to be effective for the determination of Iodine value of edible oils. Reagent (I) reacted quantitatively with the double bonds of oils of known weight. The reagent left unreacted after 20–25 min was titrated against standard sodium thiosulfate solution (0.04 M) in presence of potassium iodide (10%, 5 mL). The difference in volume of sodium thiosulfate solution consumed by reagent (I) without and with oil was a basis to calculate the iodine value of oils used. The iodine values of different oils were also determined separately following the standard procedure of Wijs, and calculated iodine value was obtained from the gas chromatographic profile of fatty acids. The iodine value obtained by the new method was in agreement with the results of the standard methods. The results obtained indicate that the method could be a complementary or an alternative to the Wijs method.
Effect of α‐ and γ‐tocopherols on thermal polymerization of purified high‐oleic sunflower triacylglycerols
Authors: Lampi Anna‐Maija , Kamal‐Eldin Afaf
Published: May 2007

The antipolymerization effects of α‐ and γ‐tocopherols were compared in model systems composed of purified high‐oleic sunflower triacylglycerols at 180°C. γ‐Tocopherol was much more effective as an antipolymerization inhibitor than α‐tocopherol, partly due to lower oxidizability/disappearance. Purified triacylglycerols of sunflower, rapeseed, and high‐oleic sunflower oils were less stable than their nonpurified forms containing tocopherols. Results confirmed that tocopherols per se can act as antipolymerization agents in high‐oleic oils at frying temperatures. No synergism was observed when α‐ and γ‐tocopherols were present together although larger amounts of residuals were left for both tocols. Results suggested that high‐oleic/high‐γ‐tocopherol oils (such as high‐oleic canola and high‐oleic soybean oils) may provide better frying oils than high‐oleic/high‐α‐tocopherol oils (such as high‐oleic sunflower oil).
Soybean lipoxygenase is active on nonaqueous media at low moisture: a constraint to xerophilic fungi and aflatoxins?
Authors: Gardner Harold W. , Grove Marilyn J. , Keller Nancy P.
Published: May 2007

Previous workers have reported that certain products of the lipoxygenase pathway are detrimental either to the development and growth of Aspergillus species or to aflatoxin production by these organisms. Since Aspergillus often thrives on “dry” stored grains, depending on the level of the relative humidity, we sought to determine if lipoxygenase could catalyze the oxidation of linoleic acid on these “dry” substrates equilibrated at various relative humidities. A desiccated model system, previously adjusted to pH 7.5, was composed of soybean extract, linoleic acid, and cellulose carrier. The model system was incubated for up to 24 h at four relative humidities ranging between 52 and 95% to determine the extent of oxidation catalyzed by lipoxygenase, compared with heat‐inactivated controls. Oxidation in the active samples was much greater than in the controls at all relative humidities, and oxidation was principally enzymatic as demonstrated by chiral analysis of the linoleate hydroperoxides formed. The main product was 13S‐hydroperoxy‐9Z,11E‐octadecadienoic acid, accompanied by a significant percentage of 9S‐hydroperoxy‐10E,12Z‐octadecadienoic acid. Since the products became more racemic with time of incubation, autoxidation appeared to be initiated by the lipoxygenase reaction in dry media. Additionally, the biological relevance of lipoxygenase activity was tested under these xerophilic conditions. Thus, enzyme‐active and heat‐inactivated defatted soy flour amended either with or without 3.5% by weight linoleic acid was inoculated with fungal spores and incubated at 95% relative humidity. Although fungal growth occurred on all treatments, samples inoculated with Aspergillus parasiticus showed significantly less aflatoxin in the enzyme‐active samples, compared to inactivated flour. Addition of linoleic acid had little effect, possibly because the defatted soy flour was found to contain 1.7% residual linoleic acid as glyceride lipid.
The influence of chemical interesterification on the physicochemical properties of complex fat systems. 2. Morphology and polymorphism
Authors: Rousseau Dérick , Marangoni Alejandro G. , Jeffrey Ken R.
Published: May 2007

Palm oil‐soybean oil (POSBO) blends and lard‐canola oil (LCO) blends were chemically interesterified with sodium methoxide. Changes in crystal morphology using polarized light microscopy and crystal polymorphic behavior using X‐ray diffraction spectroscopy (XRD) were studied. Spherulitic crystalline particles, measuring 10–20 µm, were detected in palm oil (PO). These spherulitic particles were characterized by a dense core surrounded by a lower‐density halo region. PO fat‐crystal morphology was not greatly altered on addition of soybean oil (SBO), except for a gradual reduction in spherulite size as the amount of SBO in the blends was increased. Chemical interesterification (IE) did not alter PO or POSBO blend fat‐crystal morphology significantly. Irregular particles and spherulites of different sizes and shapes were observed in lard, from small crystals to irregular, angular crystal aggregates. Changes in lard fat‐crystal morphology due to the addition of canola oil (CO) were concentration‐dependent. In general, spherulite diameter decreased with increasing CO addition. IE dramatically altered lard fat‐crystal morphology—IE induced the formation of more symmetrical spherulitic crystalline particles, and the halo‐to‐core ratio was increased significantly. XRD spectroscopic analysis of POSBO blends revealed small changes in the long spacings of PO fat crystals with either blending or IE; all values were close to 45 Å. Short spacings of fat crystals in noninteresterified (NIE) POSBO blends suggested the predominance of β′ polymorphs. IE led to an increase in the proportion of the β polymorph in PO and POSBO blends. Long spacings of NIE lard fat crystals suggested the presence of a bilayer structure in their unit cells (45 Å). Dilution with ≥10% canola oil led to the appearance of a second reflection at 35 Å. β′ polymorphs were predominantly detected in NIE lard and NIE LCO blends. The β polymorph became more evident with increasing addition of CO. Fat crystals in IE lard and IE LCO blends displayed a single long‐spacing reflection at 40 Å. IE of lard and LCO blends induced the formation of β polymorphs.
A fully robotic method for the determination of acid values in olive oil without titration
Authors: Velasco‐Arjona A. , Luque de Castro M. D.
Published: May 2007

A method for the determination of acid values (AV) in olive oil without titration is proposed, based on pH measurements on an oil sample emulsion in a suitable reagent and fully automated using a robotic station. The robot performs the weighing of the sample, adds the reagent, emulsifies both, and measures the pH of the emulsion. The data are acquired and treated by the computer. After optimization, two versions of the measurement step (interpolation within a calibration curve and addition of standard) are developed and applied to 51 oil samples with AV values that also have been determined by the standard method based on potentiometric titration. Both versions are statistically compared with the standard method, and no significant differences are found. Excellent correlation (R>0.99) between all three methods demonstrates the usefulness of the fully automated approach that works at a sample rate of 15 sample h−1 with relative standard deviations lower than 2.5%.
Triglyceride analysis by gas chromatography in assessment of authenticity of goat milk fat
Authors: Fontecha J. , Díaz V. , Fraga M. J. , Juárez M.
Published: May 2007

The triglyceride (TG) composition of 35 samples of milk collected at different times of year from five herds of goats was analyzed using short capillary column‐gas chromatography. The distribution of TG in goat milk fat was unimodal, peaking at C40 (12.6%); the sum of TG from C38 to C44 accounted for about 50%, whereas the three classes of TG from C48 to C52 did not exceed 6% each. These results were compared with the corresponding data for cow milk fat. Significant differences between herds were observed, mainly in long‐chain TG. To detect foreign fats in goat milk fat, two multiple regression equations based on TG content of the goat milk fat were proposed. Analysis of known mixtures of tallow, palm oil, and cow milk fat with goat milk fat have experimentally confirmed the accuracy of the equations.
Oat lipids
Authors: Zhou Meixue , Robards Kevin , Glennie‐Holmes Malcolm , Helliwell Stuart
Published: May 2007

Oats are a significant world crop. While nutritional interest in food oats has concentrated on oats as a source of dietary fiber, the lipid component has both nutritional and technological potential. Thus, the lipid fraction of the oat grain determines in large measure its energy content and has a significant impact on nutritional quality. The oat lipids mediate the pasting properties of oat starch and hence influence functionality. Lipids are also implicated in the flavor/off‐flavor attributes of oats. These aspects of oat lipids are reviewed together with analytical methods for assessing the lipid content of oats.
The electrochemical hydrogenation of edible oils in a solid polymer electrolyte reactor. II. Hydrogenation selectivity studies
Authors: An Weidong , Hong Jin Ki , Pintauro P. N. , Warner Kathleen , Neff William
Published: May 2007

Soybean oil has been hydrogenated electrochemically in a solid polymer electrolyte (SPE) reactor at 60°C and 1 atm pressure. These experiments focused on identifying cathode designs and reactor operation conditions that improved fatty acid hydrogenation selectivities. Increasing oil mass transfer into and out of the Pd‐black cathode catalyst layer (by increasing the porosity of the cathode carbon paper/cloth backing material, increasing the oil feed flow rate, and inserting a turbulence promoter into the oil feed flow channel) decreased the concentrations of stearic acid and linolenic acid in oil products [for example, an iodine value (IV) 98 oil contained 12.2% C18:0 and 2.3% C18:3]. When a second metal (Ni, Cd, Zn, Pb, Cr, Fe, Ag, Cu, or Co) was electrodeposited on a Pd‐black powder cathode, substantial increases in the linolenate, linoleate, and oleate selectivities were observed. For example, a Pd/Co cathode was used to synthesize an IV 113 soybean oil with 5.3% stearic acid and 2.3% linolenic acid. The trans isomer content of soybean oil products was in the range of 6–9.5% (corresponding to specific isomerization indices of 0.15–0.40, depending on the product IV) and did not increase significantly for high fatty acid hydrogenation selectivity conditions.
Quantitative analysis of palm carotene using fourier transform infrared and near infrared spectroscopy
Authors: Moh M. H. , Man Y. B. Che , Badlishah B. S. , Jinap S. , Saad M. S. , Abdullah W. J. W.
Published: May 2007

β‐Carotene content is usually determined by using ultraviolet (UV)‐visible spectrophotometry at 446 nm. In this study, two spectroscopic techniques, namely, Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopy, have been investigated and compared to UV‐visible spectrophotometry to measure the β‐carotene content of crude palm oil (CPO). Calibration curves ranging from 200 to 800 ppm were prepared by extracting β‐carotene from original CPO using open‐column chromatography. Separate partial least squares calibration models were developed for predicting β‐carotene based on the spectral region from 976 to 926 cm−1 for FTIR spectroscopy and 546 to 819 nm for NIR spectroscopy. The correlation coefficient (R2) and standard error of calibration obtained were 0.972 and 25.2 for FTIR and 0.952 and 23.6 for NIR techniques, respectively. The validation set gave R2 of 0.951 with standard error of performance (SEP) of 25.78 for FTIR technique and R2 of 0.979 with SEP of 19.96 for NIR technique. The overall reproducibility and accuracy did not give comparable results to that of spectrophotometric method; however, the standard deviation of prediction was still within ±5% β‐carotene content over the range tested. Because of their rapidness and simplicity, both FTIR and NIR techniques provide alternative means of measuring β‐carotene content in CPO. In addition, these two spectroscopic techniques are environmentally friendly since no solvent is involved.
Tectonic relief of Inner Asia between Tarim and Lake Valley
Authors: Ufimtsev G.F.
Published: May 2007

The relief of a vast area of western China and southern Mongolia was analyzed by methods of specialized morphometry to reveal structural and morphological features of recent tectonism. The tectonic relief of some part of the collisional system of Inner Asia, including the eastern Tien Shan, Govi Altay, and Bei Shan, is characterized by a general decrease in heights from west to east and a complicated system of domal ridges and intermontane troughs controlled by lenticular-rhombic faulting in the upper lithosphere. Submeridional transverse linear lows play an important role in the structure of the tectonic relief. It is likely that they are due to an irregular longitudinal flow of lithosphere blocks in the process of submeridional transverse compression. The structural signature of collisional geodynamics is traced eastward to the Ordos Province in a large meander of the Huang He and northward to the Hangayn Mountains, Tuva, and southern Gorny Altai. The predominance of domal deformations in young uplifts and no signs of their block desintegration suggest a crucial role of vertical tectonic motions largely responsible for the recent tectonic style of the eastern Tien Shan and Altay.
“Irritation and stripping effects of adhesive tapes on skin layers of coronary artery bypass graft patients,”
Authors: Christoph Susan B.
Published: May 2007

B B Weber et al, “Irritation and stripping effects of adhesive tapes on skin layers of coronary artery bypass graft patients,” Heart and Lung 16 (September 1987) 567–572.
Patients & Purse Strings: Patient Classification and Cost Management.
Authors: PAWLOWSKI JACQUELINE
Published: May 2007

Patients & Purse Strings: Patient Classification and Cost Management. Franklin A. Shaffer, ed. National League for Nursing, 10 Columbus Circle, New York, NY 10019, 1986, 362 pp, $23.95 paperback.
The time of day and the proportions of macronutrients eaten are related to total daily food intake
Authors: de Castro John M.
Published: May 2007

Intake in the morning is particularly satiating and associated with lower total amounts ingested for the day while intake at night is associated with greater overall daily intake. But, the influence of carbohydrates, fats or proteins ingested at various times of the day is unknown. The intakes of 375 male and 492 female free-living individuals that were acquired with 7 d diet-diary reports were reanalysed. The intakes of carbohydrates, fats and proteins, and the density of intake occurring during three 6 h periods (06.00 to 11.59 hours (morning), 12.00 to 17.59 hours (afternoon) and 18.00 to 23.59 hours (evening)) were identified and related to overall daily and meal intakes. Energy density of intake during all periods was found to be positively related to overall intake. When the proportion of daily carbohydrate ingested in the morning was high, less total food energy and carbohydrate were ingested over the entire day. When the proportion of daily fat ingested in the morning was high, less total food energy and carbohydrate and fat were ingested over the entire day. When the proportion of daily protein ingested in the morning was high, less protein was ingested over the entire day. Conversely, when intake was relatively high in the evening of either total food energy, carbohydrate or fat, then overall daily energy intakes tended to be higher. The results suggest that the morning intake association with reduced total intake is macronutrient specific, with morning carbohydrate, fat and protein intake associated with reduced daily carbohydrate, fat and protein intake, respectively.
25-Hydroxyvitamin D3 affects vitamin D status similar to vitamin D3 in pigs – but the meat produced has a lower content of vitamin D
Authors: Jakobsen Jette , Maribo Hanne , Bysted Anette , Sommer Helle M. , Hels Ole
Published: May 2007

In food databases, the specific contents of vitamin D3 and 25-hydroxyvitamin D3 in food have been implemented in the last 10 years. No consensus has yet been established on the relative activity between the components. Therefore, the objective of the present study was to assess the relative activity of 25-hydroxyvitamin D3 compared to vitamin D3. The design was a parallel study in pigs (n 24), which from an age of 12 weeks until slaughter 11 weeks later were fed approximately 55 μg vitamin D/d, as vitamin D3, in a mixture of vitamin D3 and 25-hydroxyvitamin D3, or 25-hydroxyvitamin D3. The end-points measured were plasma 25-hydroxyvitamin D3, and in the liver and loin the content of vitamin D3 and 25-hydroxyvitamin D3. Vitamin D3 and 25-hydroxyvitamin D3 in the feed did not affect 25-hydroxyvitamin D3 in the plasma, liver or loin differently, while a significant effect was shown on vitamin D3 in the liver and loin (P < 0·001). 25-Hydroxyvitamin D3 in the plasma, liver and loin significantly correlates with the sum of vitamin D3 and 25-hydroxyvitamin D3 in the feed (P < 0·05). Therefore, 25-hydroxyvitamin D3 should be regarded as having the same activity as vitamin D3 in food databases. Sole use of 25-hydroxyvitamin D3 as a vitamin D source in pig feed will produce liver and meat with a negligible content of vitamin D3, while an increased content of vitamin D3 in the feed will produce liver and meat with increased content of both vitamin D3 and 25-hydroxyvitamin D3.
THE PREFERENCE FOR AN ADDITIONAL CHILD AMONG MARRIED WOMEN IN SEOUL, KOREA
Authors: MI PARK SANG , IL CHO SUNG , NANG JANG SOONG , TAE CHO YOUNG , WON CHUNG HAI
Published: May 2007

South Korea reported a total fertility rate (TFR) of 1·08 in 2005. This is the lowest level of all nations in the Organisation for Economic Co-operation and Development (OECD). Recently, the decline in the fertility rate has been a dominant phenomenon in Korea’s major cities. This study investigated the relationship between social environmental factors and fertility intentions for married women in Seoul, the capital of Korea, using a sample of 2211 married women who responded to the Seoul Citizens Health and Social Indicators Survey, 2005. Here, the effects of selected social environmental characteristics on fertility intentions are explored using multivariate logistic regression models. The relationships among a woman’s age, number of living children, job type, housing type, and social group participation were strong indicators of the intention to have additional children. Younger women living with fewer children generally have a higher intention to have additional children. Among women’s job types, blue-collar workers have a lower preference for additional children than white-collar workers and housewives. Married women participating in social groups have a lower preference for additional children than non-participants. Women’s participation in social activities appears to have various benefits, both individually and socially. However, whereas women’s participation in economic activities has been linked to questions of fertility in previous studies, the relationship between fertility and social activities has been downplayed. Women’s participation in social activities has increased over the past several decades, and the trend continues to grow. Therefore, women’s participation in social activities must be accepted as the status quo, and compatibility between women’s participation in social activities and childrearing needs to be increased. Consequently, a strong foundation for a fertility-friendly environment is needed, focusing on blue-collar workers and participation in social activities by married women.