bluuebunny/crossref_metadata_2025 huggingface dataset:
The oxidation of penicillin‐G‐potassium salt using supported polyoxometalates with hydrogen peroxide
Authors: Brown Scott W. , Johnstone Alexander , Jones Craig W. , Lee Angela M. , Oakes Steven C. , Wilson Sharon L.
Published: September 2010

The oxidation of the sulfide group in penicillin G potassium salt to the sulfoxide with hydrogen peroxide has been investigated using a wide range of polyoxometalates immobilized on high‐surface‐area supports. The highest activity and selectivity for the sulfur oxidation of the penicillin compound was obtained with ammonium molybdate supported on to strongly basic anion‐exchange resin. The oxidation proceeds smoothly at ambient and sub‐ambient temperatures in water or water/alcohol solvents. The use of supported oxidation catalysts has been extended to the transformation of benzenethiol to benzenesulfonic acid which was found to proceed in high yield and selectivity employing phosphotungstic acid on γ‐alumina. The use of a supported catalyst with H2O2 as the primary oxidant allows the circumvention of environmental and product isolation problems to be overcome simply and economically.
Gas‐phase hydrogenolysis mediated by activated carbon: Deuterated benzenes
Authors: Arends Isabel W. C. E. , Louw Robert , Mulder Peter
Published: September 2010

Hydrogenolyses of hexadeuterobenzene C6D6 and pentadeuterochlorobenzene C6D5Cl have been studied in flow reactors packed with activated carbon (AC) between 300° and 600°C, with void residence times of 4‐5 s. At 579°C overall dedeuteration ‐ proceeding in a near statistical manner ‐ was close to 40% in both cases, whereas C6D5Cl is almost completely dechlorinated to deuterated benzenes at 505°C. On a per‐site basis, replacement of Cl by H is ca. 20 times faster than that of D.

These results clearly demonstrate a catalytic activity of AC in both cases of desubstitution. In the absence of AC, temperatures of 700‐900°C are necessary to obtain the same result. Then, replacement of Cl and D have almost equal rates, both reactions occurring via addition of free H atoms. In the AC‐mediated reactions, the yields of (D) benzenes are quantitative from C6D6, but around 50% with C6D5Cl. Apparently the latter compound reacts with bonding of its phenyl group to the AC surface, whereas D → H substitutions involve H transfer to a physisorbed (D) benzene.
Synthesis and characterization of 9,10‐bis(arylimino)‐9,10‐dihydrophenanthrenes, the structure of (Z,Z)‐9,10‐bis(phenylimino)‐9,10‐dihydrophenanthrene and PdCl2‐[(E,E)‐9,10‐bis(phenylimino)‐9,10‐dihydrophenanthrene] in the solid state and in solution
Authors: van Belzen Ruud , Klein René A. , Smeets Wilberth J. J. , Spek Anthony L. , Benedix Roland , Elsevier Cornells J.
Published: September 2010

The synthesis and characterization of substituted phenanthrene‐9,10‐quinone diimines of the type 9,10‐bis(arylimino)‐9,10‐dihydrophenanthrene (aryl‐BIP) is described. These rigid bisnitrogen ligands have been synthesized by a metal‐mediated cyclodehydrogenation reaction from the aromatic open‐chain diimine analogues derived from benzil. All aryl‐BIP compounds adopt a Z,Z configuration in solution except for (o‐iPr‐phenyl)‐BIP, which mainly exists in the E,Z form. All non‐cyclic BIP compounds undergo a configurational change into the E,E isomer upon coordination to palladium. NDDO calculations on phenyl‐BIP and its palladium dichloride complex have revealed that the energy of the LUMO is very much dependent on the puckering of the phenanthrene backbone and is in all cases lower than, for instance, that of the aromatic diimine of acenaphthene‐1,2‐quinone or open‐chain diimines. The structures of phenyl‐BIP and PdCl2‐(phenyl‐BIP) in the solid state have been determined by X‐ray diffraction. Phenyl‐BIP is triclinic, space group P̄, a = 12.392(1), b = 12.478(1), c = 14.633(2) Å, α = 109.36(1), β = 91.57(1), γ = 115.82(1)°, Z = 4, final R = 0.0556 for 4494 reflections with I > 2.5σ(I). PdCl2‐(phenyl‐BIP) is monoclinic, space group P21/c, a = 20.5148(9), b = 10.6756(9), c = 23.2007(16) Å, β = 105.13(1)°, Z = 4, final R = 0.0701 for 2569 reflections with I > 2.5σ(I).
Spontaneous crystallization in undercooled liquid mixtures of l‐limonene + l‐carvone
Authors: Calvet T. , Cuevas‐Diarte M.A. , Gallis H.E. , Oonk H.A.J.
Published: September 2010

The two related monoterpenes l‐carvone (m.p. −29°C) and l‐limonene (m.p. −74°C) when cooled to −120°C in DSC experiments remain in the liquid state. On subsequent heating to room temperature carvone crystallizes spontaneously at −75°C whereafter it melts at −29°C. Limonene, on the other hand, does not crystallize at all; to understand its behaviour, mixtures with carvone were investigated.
Facile synthesis of 2‐substituted benzoxazoles via ketenes
Authors: Olagbemiro T.O. , Agho M.O. , Abayeh O.J. , Amupitan J.O.
Published: September 2010

The generation of diphenyl‐, phenyl‐, phenoxy‐, and chloroketenes by treatment of the corresponding acid chlorides with triethylamine in the presence of 2‐aminophenol resulted in good yields of 2‐substituted benzoxazoles.
Synthesis of niruriside a HIV REV/RRE binding inhibitor
Authors: Duynstee H.I. , Ovaa H. , van der Marel G.A. , van Boom J.H.
Published: September 2010

Regioselective acylation of 2,1′:4,6‐di‐O‐isopropylidene‐D‐sucrose (2) with trans‐cinnamoyl chloride gave intermediate 3, which was transformed in four steps into niruriside (1) in 23% overall yield. On the other hand, conversion of 2 into 1′,2,4,6‐tetra‐O‐acetylsucrose 10 followed by cinnamoylation gave (1) in 41% overall yield.
Separation of 2‐ and 4‐hydroxymandelic acid
Authors: Hoefnagel A.J. , Peters J.A. , van Bekkum H.
Published: September 2010

Hydroxyalkylation of phenol with glyoxylic acid, catalyzed by AlIII, results, under neutral aqueous conditions, in ortho‐rich mixtures of hydroxymandelic acids. Para‐rich mixtures of hydroxymandelic acids are obtained by ZnII catalysis under slightly alkaline conditions. A new separation method of these mixtures into the pure alkali salts of 2‐ and 4‐hydroxymandelic acid is presented. Formation of a complex between the alkali ion and three co‐operating oxygen atoms of 2‐hydroxymandelate explains the excellent solubility of the ortho isomer in acetone, enabling extraction of this isomer selectively from mixtures of alkali salts of 2‐ and 4‐hydroxymandelic acid.
Receptors functionalized with chiral aza‐crown ether rings. Attempted enantioselective catalysis of a Michael addition reaction
Authors: Schuurman Ruud J. W. , Grimbergen Reinier F. P. , Scheeren Hans W. , Nolte Roeland J. M.
Published: September 2010

A series of receptors functionalized with chiral aza‐crown ether rings was synthesized. These compounds were studied as enantiopure catalysts for the addition of benzenethiols to cyclohex‐2‐en‐1‐one. Binding of 4‐hydroxybenzenethiol in these molecules allows for the orientation of the thiol with respect to an asymmetric catalytic site. This orientation was, however, found to be counterproductive for enantioselective catalysis.
1‐Alkyl‐4‐(alkylamino) quinolinium‐3‐thiolates
Authors: Maślankiewicz Andrzej , Ziȩba Andrzej , Glowiak Tadeusz
Published: September 2010

Reaction of 5,12‐dialkylthioquinanthrenediinium bis‐salts 1 with primary alkylamines led to the synthesis of 1‐alkyl‐4‐(alkylamino)quinolinium‐3‐thiolates (2). Their structures were proved by X‐ray examination, 1H‐NMR spectroscopy and by transformation to 1‐alkyl‐4‐(alkylamino)‐3‐(alkylthio)quinolinium salts (3).
Oxidation catalysis by biomimetic manganese complexes
Authors: Hage Ronald
Published: September 2010

A review is given of certain aspects of manganese‐containing enzymes, such as manganese superoxide dismutase, manganese catalase, and the photosynthetic oxygen‐evolving catalyst. A variety of manganese complexes have been synthesized to model either the structure of the active site of these enzymes (structural models), or their function (functional models). Most of the enzymatic reactions can be mimicked by functional models, albeit at much lower reaction rates. Additionally, a number of manganese complexes based on the structural mimics, have been studied as catalysts in oxidation reactions other than the enzymatic ones.

Examples of functional models for superoxide dismutase, catalase and the water oxidation catalyst in plants, as well as a number of manganese complexes catalyzing a variety of other oxidation reactions, are also discussed in this review.
Solid‐support synthesis of di‐ and tetramannosylated tetrathymidylic acid
Authors: Wijsman E.R. , Filippov D. , Valentijn A.R.P.M. , van der Marel G.A. , van Boom J.H.
Published: September 2010

The easy accessible building units 5‐O‐(2,3,4,6‐tetra‐O‐benzoyl‐α‐D‐mannopyranosyl)penyl 2‐cyanoethyl N,N‐diisopropylphosphoramidite (9) and 2,2‐bis(4,4′‐dimethoxytrityloxymethyl)propyl 2‐cyanoethyl N,N‐diisopropylphosphoramidite (12) were used for the sequential elongation of immobilized tetrametric thymidylic acid according to a DNA synthesis protocol. Ammonolysis of the individual immobilized adducts led to the isolation of the target compounds 1 and 2.
5,17‐Bis(acetamido)‐25,26,27,28‐tetrapropoxycalix[4]arene; the first example of two different pinched cone conformations in the solid state
Authors: Verboom Willem , Vreekamp Remko H. , Bodewes Paul J. , Reinhoudt David N. , Harkema Sybolt
Published: September 2010

Crystals of 5,17‐bis(acetamido)‐25,26,27,28‐tetrapropoxycalix[4]arene · ethyl‐acetate (1: 1), C44H54N2O6 · C4H8O2 are triclinic, space group P‐1, a = 13.319(4), b = 15.519(4), c = 22.386(6) Å, α = 104.73(3), β = 99.02(3), γ = 95.30(3)°, T = 100(5) K, Z = 4. The asymmetric unit contains two calix[4]arene molecules and two ethyl acetate molecules. The two calix[4]arene molecules have different pinched cone conformations. The phenyl rings show small but consistent boat‐like deformations. The final R factor is 7.9%.
Chemo‐ and diastereoselective cyclic ketalization of optically pure 1‐aryl‐2,2‐dimethylpropane‐1,3‐diols with phenylglyoxal
Authors: Xianming Hu , Kellogg Richard M.
Published: September 2010

Reactions of optically pure 1‐aryl‐2,2‐dimethylpropane‐1,3‐diols with phenylglyoxal give diastereomerically pure cyclic ketals under acid catalyzed conditions. The structure of one of the products, 2‐phenyl‐4‐(2‐chlorophenyl)‐5,5‐dimethyl‐1,3‐dioxane‐2‐carbaldehyde (7), has been determined by X‐ray crystallography; reaction takes place at the keto group and the aldehyde group is oriented axially.
Selective de‐oxygenation of organic compounds
Authors: Ponec V.
Published: September 2010

In this paper, recent results on the de‐oxygenation of some organic molecules nitrobenzene, aliphatic carboxylic acids and benzoic acid are reviewed. The activity pattern of metal oxides in these reactions has been established, and several factors controlling the selectivity have been identified. Selectivity in the de‐oxygenation (and related) reaction is related to the universally operating Mars ‐ Van Krevelen mechanism.
Promoted platinum catalysts for automotive pollution control. Metal oxides of Co, Cr, Al, Mn, Mg, Ce, Zr, V, La, Ti and Fe as additives
Authors: Mergler Y.J. , Chandoesing R. , Nieuwenhuys B.E.
Published: September 2010

Exploratory research to develop Rh‐free, “Pt‐only”, automotive catalysts is described. Metal oxides were added as a promoter or co‐catalyst to Pt/SiP2 and the effect of the additive on NO reduction by CO has been studied. In addition, the reaction was studied over the unsupported metal oxides (MO) and Pt/MO catalysts. From the series of metal oxides tested, it is concluded that Co, Fe, Mn, Ti and V oxides show promising results as additives to Pt for the catalysis of NO reduction by CO.
Sorption of alkanes on novel pillared zeolites; comparison between MCM‐22 and MCM‐36
Authors: Eder Florian , He Yingjie , Nivarthy Gautam , Lercher Johannes A.
Published: September 2010

MCM‐22 was synthesized and modified by swelling and pillaring to obtain MCM‐36. These two structures were characterized by means of XRD, SEM, XRF, nitrogen adsorption, NH3 adsorption/desorption and IR spectroscopy. The sorption of light alkanes on the protonic form of MCM‐22 and MCM‐36 was investigated using gravimetry, calorimetry and in situ IR spectroscopy. Distinct differences in the properties of the two materials are observed. Swelling and pillaring of MCM‐22 leads to an increase in crystal size and mesopore volume, while the micropore volume and the concentration of the Brønsted acid sites decreases. The acid sites are found to be sited to a large extent in the 10‐membered‐ring channels of MCM‐22. This channel system is present in MCM‐22 and MCM‐36. As alkanes are sorbed in the same local environment in both samples, identical enthalpies of adsorption are observed. The enthalpy of adsorption varies with the entropy of sorption in a manner typical for structures consisting of 10‐membered‐ring channels. This indicates that the localized part of the alkane sorption properties on MCM‐22 and MCM‐36 is dominated by the 10‐membered‐ring channel system.
Über Komplexverbindungen im System Cr3+/Cl‐ in Dimethylsulfoxyd
Authors: Schläfer H. L. , Opitz H. P.
Published: September 2010

Es wird gezeigt, daß CrCl3 in wasserfreiem Dimethylsulfoxyd (DMSO) bei Zimmertemperatur praktisch als cis‐[Cr(DMSO)4Cl2]+‐ Ion vorliegt. Bei der aus den Lösungen auskristallisierenden grauvioletten Verbindung CrCl3 · 5 DMSO handelt es sich, wie aus dem Vergleich des Lösungs‐ mit dem Reflexionsspektrum folgt, um cis‐[Cr(DMSO)4Cl2]Cl · DMSO. Durch thermische Behandlung dieser Verbindung entsteht rotviolettes CrCl3 · 3 DMSO, das als Nichtelektrolytkomplex [Cr(DMSO)3Cl3] zu formulieren ist.

In den Lösungen von cis‐[Cr(DMSO)4Cl2]+ existiert das reversible Gleichgewicht cis‐[Cr(DMSO)4Cl2]+ + Cl‐ ⇌ [Cr(DMSO)3Cl3] + DMSO, das sich bei höheren Temperaturen zum rotvioletten Trichlorokomplex verschiebt. Das Gleichgewicht wird mit Hilfe von spektrophotometrischen und von Leitfähigkeitsmessungen untersucht.
Physikalische Stabilität und Elektronenverteilung in homonuklearen mehratomigen linearen Molekülen
Authors: Müller Hans
Published: September 2010

Mit Hilfe eines einfachen dreidimensionalen FE‐Modells werden die im Kohlenstoffdampf auftretenden linearen Moleküle Ck (k = 1, 2, 3, …) behandelt. Im Anschluß an die Untersuchung der physikalischen Stabilität findet eine ausführliche Diskussion der Elektronenverteilung in diesen Molekülen statt, die qualitativ an Hand des Bindungscharakters der FE‐MO's und quantitativ mittels einer Elektronenpopulationsanalyse speziell für C3 und C4 durchgeführt wird. Die Ergebnisse entsprechen der Struktur : C = C = … = C:. Ferner findet ein Vergleich mit den linearen Aktivierungskomplexen H3 und H4 statt.
Über die Möglichkeiten der röntgenspektroskopischen Untersuchung von Katalysatoren
Authors: Gáti Gy. , Meisel A.
Published: September 2010

Im ersten Teil dieser Arbeit werden Überlegungen angestellt, in wieweit die Methoden der Röntgenemissions‐ und ‐absorptionsspektroskopie zur Aufklärung der elektronischen Struktur von Katalysatoren und ihrer Änderung durch Wechselwirkungen des Katalysators mit Trägersubstanzen und chemisorbierten Molekülen beitragen können. Im zweiten Teil werden weitere Möglichkeiten der röntgenspektroskopischen Katalysatoruntersuchung am Beispiel des WS2 beschrieben. Durch Aufnahme des S Kα‐Dubletts wird die Möglichkeit der Bestimmung der Konzentration verschiedener Wertigkeitsstufen erörtert, und auf Grund der W L‐Emissions‐ und ‐Absorptions‐spektren wird die elektronische Struktur des Wolframdisulfids im Zusammenhang mit seinen katalytischen Eigenschaften diskutiert.
Flüssige Ionenaustauscher — I. Wesen und Anwendung
Authors: Häupke Klaus , Wolf Friedrich
Published: September 2010

Die Bezeichnung „flüssige Ionenaustauscher”︁ hat sich in letzter Zeit für eine Gruppe ionenselektiver Extraktionsmittel eingeführt, die aus Lösungen von nicht wasserlöslichen ionogenen Verbindungen (langkettigen sauren Phosphorsäureestern oder langkettigen Aminen) in mit Wasser nicht mischbaren Lösungsmitteln be‐stehen. Sie eignen sich speziell zur Extraktion von Metallen zum Zweck der Gewinnung, Reinigung oder Trennung auf nassem Wege. Es wird ein Überblick über die bekanntgewordenen flüssigen Ionenaustauscher, ihre Anwendung und ihre Wirkungsweise gegeben.
Interhalogenverbindungen
Authors: Meinert Hasso
Published: September 2010

Von den binären Interhalogenen sind die Typen AB, AB3, AB5und AB7, von den ternären die Verbindungen JCIF und JCIF2bekannt.

Über Interhalogene sind bereits mehrere Übersichts‐ bzw. Teilübersichtsartikel erschienen [1]‐[10]. In den letzten Jahren ist aber so viel Neues über diese Verbindungsklasse berichtet worden, daß eine Zusammenfassung angebracht erscheint.
Fraktionierung, Struktur und mögliche biologische Funktion der Histone
Authors: Schwenke Klaus Dieter
Published: September 2010

Forschungsstelle für Experimentelle Onkologie der Deutschen Akademie der Wissenschaften zu Berlin in Potsdam‐Rehbrucke

jetzt: Arbeitsgruppe Dr. med. habil F. Schmidt im Institut für Ernährung der DAW zu Berlin in Potsdam‐Rehbrücke.
Vergleichende Untersuchungen zur Einsatzmöglichkeit des kaskadenstabilisierten Lichtbogens
Authors: Doerffel Klaus , Gehlsen‐Lorenzen Hans‐Peter Timm , Mann Ute
Published: September 2010

Im Verlaufe bisheriger Untersuchungen hat sich der kaskadenstabilisierte Lichtbogen nach Riemann [1] als wertvolles analytisches Hilfsmittel erwiesen. Im folgenden soll versucht werden, die Eigenschaften dieser Lichtquelle in den Vergleich mit Verbrennungsflamme, Plasmastrahlerzeuger und Atomabsorption zu stellen und hieraus Rückschlüsse auf jeweils optimale Einsatzmöglichkeit abzuleiten.
Long‐term observational, non‐randomized study of enzyme replacement therapy in late‐onset glycogenosis type II
Authors: Bembi Bruno , Pisa Federica Edith , Confalonieri Marco , Ciana Giovanni , Fiumara Agata , Parini Rossella , Rigoldi Miriam , Moglia Arrigo , Costa Alfredo , Carlucci Annalisa , Danesino Cesare , Pittis Maria Gabriela , Dardis Andrea , Ravaglia Sabrina
Published: September 2010

Objectives

Type II glycogenosis (GSDII) is a lysosomal storage disorder due to acid alpha‐glucosidase (GAA) deficiency. Enzyme replacement therapy (ERT) with human recombinant alpha‐glucosidase (rhGAA) has been demonstrated to be effective in the treatment of infantile forms of GSDII, but little information is available concerning late‐onset phenotypes. Long‐term follow‐up studies are not available at present. The aim of this study was to evaluate the ERT long‐term effects in late‐onset GSDII.

Methods

Twenty‐four patients, including 7 juveniles and 17 adults, received bi‐weekly infusion of rhGAA (20 mg/kg) for at least 36 months. Clinical conditions, muscular function (6‐min walking test, 6MWT; Walton scale, WS), respiratory function (vital capacity, VC; forced expiratory volume, FEV1; arterial pCO2), and muscle enzymes were assessed every 6 months.

Results

The 6MWT improved in both juvenile and adult patients (p = 0.01, p = 0.0002, respectively), as well as in patients with moderate to severe muscle function impairment (WS > 3.5; p = 0.002). An overall improvement in WS was also observed (p = 0.0003). VC and FEV1 remained unchanged, while pCO2 decreased (p = 0.017). Muscle enzymes decreased significantly (p < 0.0001). Two patients (8%) showed transient secondary events during ERT.

Conclusions

Long‐term ERT with rhGAA was shown to be safe, well tolerated, and effective in improving motor function and in stabilizing respiratory function in late‐onset GSDII. The response pattern showed a progressive clinical improvement during the follow‐up period in juvenile patients, while in adults it reached and maintained a plateau after the first year of treatment.
The parasite community of the nase Chondrostoma nasus (L. 1758) from Austrian rivers
Authors: Jirsa F. , Konecny R. , Frank C. , Sures B.
Published: September 2010

Between April 2003 and November 2006 a total of 191 individuals of the predominantly herbivorous fish species nase Chondrostoma nasus (L. 1758) were examined for parasites from six river sites in Austria. The following parasite taxa were recovered – Ciliata: Trichodina sp., Chilodonella piscicola, Ichthyophthirius multifiliis; Myxozoa: Myxobolus muelleri (cysts) and Myxobolus sp. (cysts); Monogenea: Dactylogyrus vistulae, D. chondrostomi and Dactylogyrus spp., Gyrodactylus sp., Diplozoon paradoxum; Digenea: Diplostomum spathaceum (larv.) and Tylodelphis clavata (larv.); Cestoda: Caryophyllaeus laticeps; Acanthocephala: Pomphorhynchus laevis; Bivalvia: Unio sp. (Glochidia); Crustacea: Lamproglena pulchella; Hirudinea: Piscicola geometra. The only taxa occurring at all sample sites were Dactylogyrus spp., which was also the dominant taxon at most sites, and Myxobolus muelleri, both from the gills of the fish. This is the first record of the parasite community of the nase in Austria.
Frontal sinus models and onlay templates in osteoplastic flap surgery
Authors: Daniel M , Watson J , Hoskison E , Sama A
Published: September 2010

Objective:

Precise delineation of the extent of frontal sinus pneumatisation is a crucial step in osteoplastic flap frontal sinus surgery. The authors present a novel method of achieving this objective.

Methods:

First, models of the frontal area are generated using three-dimensional printing based on pre-operative computed tomography image data. These models are then used to create an onlay template of the frontal sinus, which is used intra-operatively.

Results:

In a series of 10 patients undergoing osteoplastic flap frontal sinus surgery, the described frontal sinus templates were consistently accurate to within 1 mm.

Conclusion:

Frontal sinus templates are potentially useful adjuncts to current techniques employed to guide frontal sinus surgery.
Endaural meatoplasty: the Whipps Cross technique
Authors: Patil S , Ahmed J , Patel N
Published: September 2010

Objective:

To describe our technique of endaural meatoplasty for mastoid surgery, and to publish an online video demonstration.

Method:

After the endaural incision, a skin incision is accurately marked over the anterior conchal bowl, identified by pushing the anti-helix anteriorly. This should meet the line of the endaural incision superiorly and extend inferiorly to the lower anterior edge of the conchal cartilage. After performing the incision, a segment of conchal cartilage is removed. The soft tissue meatoplasty is facilitated by resecting a triangular segment of skin and underlying soft tissue medial to the conchal incision (on which it is based). The free edges are closed with absorbable sutures after the (attico)mastoidectomy.

Results:

We have used this method on 64 patients over the past two years. Satisfactory functional and cosmetic outcomes were achieved in all.

Conclusion:

Our technique is simple, easy to learn, quick and effective in helping to achieve our goal of a dry mastoid cavity with an adequate meatoplasty.
Existence of a measurable saturated compensation function between subshifts and its applications
Authors: YAYAMA YUKI
Published: September 2010

We show the existence of a bounded Borel measurable saturated compensation function for any factor map between subshifts. As an application, we find the Hausdorff dimension and measures of full Hausdorff dimension for a compact invariant set of an expanding non-conformal map on the torus given by an integer-valued diagonal matrix. These problems were studied in [23] for a compact invariant set whose symbolic representation is a shift of finite type under the condition of the existence of a saturated compensation function. By using the ergodic equilibrium states of a constant multiple of a Borel measurable compensation function, we extend the results to the general case where this condition might not hold, presenting a formula for the Hausdorff dimension for a compact invariant set whose symbolic representation is a subshift and studying invariant ergodic measures of full dimension. We study uniqueness and properties of such measures for a compact invariant set whose symbolic representation is a topologically mixing shift of finite type.
NONNESTED TESTING IN MODELS ESTIMATED VIA GENERALIZED METHOD OF MOMENTS
Authors: Hall Alastair R. , Pelletier Denis
Published: September 2010

We analyze the limiting distribution of the Rivers and Vuong (2002, Econometrics Journal 5, 1–39) statistic for choosing between two competing dynamic models based on a comparison of generalized method of moments minimands. It is shown that (i) if both models are misspecified then the statistic has a standard normal distribution under the null hypothesis of equal fit but the ranking could be determined by the choice of the weighting matrix; (ii) if both models are correctly specified or locally misspecified then the limiting distribution of the test statistic is nonstandard under the null.
Heuristic Drift Elimination for Personnel Tracking Systems
Authors: Borenstein Johann , Ojeda Lauro
Published: September 2010

This paper pertains to the reduction of the effects of measurement errors in rate gyros used for tracking, recording, or monitoring the position of persons walking indoors. In such applications, bias drift and other gyro errors can degrade accuracy within minutes. To overcome this problem we developed the Heuristic Drift Elimination (HDE) method, that effectively corrects bias drift and other slow-changing errors. HDE works by making assumptions about walking in structured, indoor environments. The paper explains the heuristic assumptions and the HDE method, and shows experimental results. In typical applications, HDE maintains near-zero heading errors in walks of unlimited duration.
The Risk Homeostasis Theory
Authors: Baniela Santiago Iglesias , Ríos Juan Vinagre
Published: September 2010

Statistics and information from the maritime industry show that the continuous advances in the safety of navigation do not reduce the occurrence of shipping casualties. This controversial fact leads the authors to analyse the applicability of the risk homeostasis theory to maritime transportation. With the aim of investigating this matter 2,584 ship incidents, which took place during the years 2005 and 2006, have been recorded and examined. The same variables which the Paris MOU usually employs to identify substandard ships (flag, classification society, age, type and size) have been used in this research to establish their level of safety in an effort to determine the relationship between that level and the occurrence of maritime incidents in the world cargo carrying fleet with appropriate statistical methods.
Seismic attenuation and mantle wedge temperature in the northern Apennines subduction zone (Italy) from teleseismic body wave spectra
Authors: Piccinini Davide , Di Bona Massimo , Lucente Francesco Pio , Levin Vadim , Park Jeffrey
Published: September 2010

We analyze P and S wave spectra from moderate‐ to deep‐focus teleseisms recorded at the Retreating‐Trench, Extension, and Accretion Tectonics (RETREAT) temporary broadband seismic network to assess the variations of the Earth mantle attenuation in the northern Apennines region (Italy). For each earthquake, we compute the ratio between the spectrum at each station and the average spectrum, in order to estimate t* residuals (Δt*) from the spectral ratio decay. The number and distribution of the teleseisms useable for the P wave t* calculation allow for a gross azimuthal analysis; although the (Δt*) values at single station display, in most cases, azimuthal‐dependent fluctuations, their overall distribution shows a partition of the study region into two main areas, whose gross features remain almost unchanged over the whole azimuthal range. This partition is confirmed by the S wave t* mean values, computed for each station over the set of useable events. We distinguish a relatively high attenuation area on the western, Tyrrhenian side and a relatively low attenuation area on the eastern, Adriatic side. By correlating our Δt* estimates and the velocity structure derived from the existing tomographic models, we compute the ranges of possible P and S wave Q values in the mantle wedge above the Apennines slab (on the Tyrrhenian side) and in the asthenosphere below the Adriatic region. Furthermore, the determined attenuation properties are used to draw some inferences on the thermal state of the uppermost mantle and on the physical properties of the tectonic elements, which constitute the subduction system in the region.
On potential causes for an under‐estimated global ocean heat content trend in CMIP3 models
Authors: Cai W. , Cowan T. , Arblaster J. M. , Wijffels S.
Published: September 2010

Trends in global oceanic heat content (OHC) over the late 20th century as simulated by climate models that incorporate all radiative forcing factors are smaller than the observed, but the causes are not clear. Given the cooling effect associated with increasing anthropogenic aerosols and natural forcing (i.e., volcanic aerosols), we examine their respective roles in the simulated global OHC trend and the associated ocean temperature structure, using targeted experiments from two models, designed to separate the individual impacts of these forcing components. We show that it is more likely that the indirect effect of aerosols, not volcanic aerosols alone, is the reason for the bulk of weaker modelled OHC trends. Further, anthropogenic aerosols are essential for simulating the structure of the observed temperature changes, including a concentrated cooling in the Southern Hemisphere subtropical latitudes, consistent with a more stable global Conveyer, a greater strengthening of the subtropical gyre circulation, and a stronger Southern Annular Mode trend in targeted experiments with anthropogenic aerosol forcing.
Origin of backstreaming electrons within the quasi‐perpendicular foreshock region: Two‐dimensional self‐consistent PIC simulation
Authors: Savoini P. , Lembége B. , Stienlet J.
Published: September 2010

The foreshock region is populated by energetic backstreaming particles (electrons and ions) issued from the shock after having interacted with it. Several aspects concerning the origin of these high‐energy particles and their corresponding acceleration mechanisms are still unresolved. The present study is focused on a quasi‐perpendicular curved shock and associated electron foreshock region (i.e., for 90° ≥ θBn ≥ 45°, where θBn is the angle between the shock normal and the upstream magnetostatic field). Two‐dimensional full‐particle simulation is used in order to include self‐consistently the electron and ion dynamics, the full dynamics of the shock, the curvature effects and the time‐of‐flight effects. All expected salient features of the bow shock are recovered both for particles and for electromagnetic fields. Present simulations evidence that the fast‐Fermi acceleration (magnetic mirror) mechanism, which is commonly accepted, is certainly not the unique process responsible for the formation of energetic backstreaming electrons. Other mechanisms also contribute. More precisely, three different classes of backstreaming electrons are identified according to their individual penetration depth within the shock front: (i) “magnetic mirrored” electrons which only suffer a specular reflection at the front, (ii) “trapped” electrons which succeed to penetrate the overshoot region and suffer a local trapping within the parallel electrostatic potential at the overshoot, and (iii) “leaked” electrons which penetrate even much deeper into the downstream region. “Trapped” and “leaked” electrons succeed to find appropriate conditions to escape from the shock and to be reinjected back upstream. All these different types of electrons contribute together to the formation of energetic field‐aligned beam. The acceleration mechanisms associated to each electron class and/or escape conditions are analyzed and discussed.
Design of Kerr-effect sensitive microcavity in nonlinear photonic crystal slabs for all-optical switching
Authors: Qin Fei , Liu Ye , Meng Zi-Ming , Li Zhi-Yuan
Published: September 2010

We design a Kerr-effect sensitive microcavity in hybrid semiconductor nonlinear photonic crystal (PhC) slabs for application in all-optical switching. Our new concept cavity is made from infiltrating the air hole array and coating the surface of usual semiconductor PhC slabs with polystyrene, and let the polystyrene instead of the semiconductor occupy the center of the cavity. Optimization of the cavity design by modulating the structure parameter yields a quality factor Q=1600 and shift magnitude δf≈8.4 nm while pumping the cavity with a light intensity of 80 GW/cm2. This cavity configuration can help to realize very fast response speed and low pump intensity in all-optical switching devices, reduce the demand for rigorous precision during the high-Q PhC cavity fabrication, and allow for easy integration with other integrated optical components.
Ferromagnetic resonance study of Permalloy/Cu/Co/NiO spin valve system
Authors: Ben Youssef J. , Layadi A.
Published: September 2010

Ferromagnetic resonance, in 7 to 18 GHz frequency range, is used to investigate a series of rf sputtered Permalloy (Py)/Cu/Co trilayers and Py/Cu/Co/NiO spin valve system. The experimental data, frequency versus applied magnetic field, agree quit well with the theoretical model. The magnetic coupling between Py and Co is found to be ferromagnetic with effective magnetic coupling parameter values increasing from 0.05 to 0.1 erg/cm2 as the interlayer Cu thickness decreases from 10 to 2 nm. While the magnetic coupling leads to a decrease in the resonance fields, HR, of the modes, the exchange anisotropy at the Co/NiO interface shifts the mode upwards. However the shift is more important for the optical mode than for the acoustic one. Hysteresis curves, qualitatively, confirm the ferromagnetic coupling. The antiferromagnetic NiO layer leads to a slight increase in the coercive field.
Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing
Authors: Nagae Daisuke , Mase Atsushi
Published: September 2010

In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.
Radial current high power dummy load for characterizing the high power laser triggered transformer-type accelerator
Authors: Yin Yi , Zhong Hui-Huang , Liu Jin-Liang , Ren He-Ming , Yang Jian-Hua , Zhang Xiao-Ping , Hong Zhi-qiang
Published: September 2010

A radial-current aqueous resistive solution load was applied to characterize a laser triggered transformer-type accelerator. The current direction in the dummy load is radial and is different from the traditional load in the axial. Therefore, this type of dummy load has smaller inductance and fast response characteristic. The load was designed to accommodate both the resistance requirement of accelerator and to allow optical access for the laser. Theoretical and numerical calculations of the load’s inductance and capacitance are given. The equivalent circuit of the dummy load is calculated in theory and analyzed with a PSPICE code. The simulation results agree well with the theoretical analysis. At last, experiments of the dummy load applied to the high power spiral pulse forming line were performed; a quasisquare pulse voltage is obtained at the dummy load.
Gas loading apparatus for the Paris-Edinburgh press
Authors: Bocian A. , Bull C. L. , Hamidov H. , Loveday J. S. , Nelmes R. J. , Kamenev K. V.
Published: September 2010

We describe the design and operation of an apparatus for loading gases into the sample volume of the Paris-Edinburgh press at room temperature and high pressure. The system can be used for studies of samples loaded as pure or mixed gases as well as for loading gases as pressure-transmitting media in neutron-scattering experiments. The apparatus consists of a high-pressure vessel and an anvil holder with a clamp mechanism. The vessel, designed to operate at gas pressures of up to 150 MPa, is used for applying the load onto the anvils located inside the clamp. This initial load is sufficient for sealing the pressurized gas inside the sample containing gasket. The clamp containing the anvils and the sample is then transferred into the Paris-Edinburgh press by which further load can be applied to the sample. The clamp has apertures for scattered neutron beams and remains in the press for the duration of the experiment. The performance of the gas loading system is illustrated with the results of neutron-diffraction experiments on compressed nitrogen.
Integrating in situ high pressure small and wide angle synchrotron x-ray scattering for exploiting new physics of nanoparticle supercrystals
Authors: Wang Zhongwu , Chen Ou , Cao Charles Y. , Finkelstein Ken , Smilgies Detlef-M. , Lu Xianmao , Bassett William A.
Published: September 2010

Combined small and wide angle synchrotron x-ray scattering (SAXS and WAXS) techniques have been developed for in situ high pressure samples, enabling exploration of the atomic structure and nanoscale superstructure phase relations. These studies can then be used to find connections between nanoparticle surfaces and internal atomic arrangements. We developed a four-axis control system for the detector, which we then employed for the study of two supercrystals assembled from 5 nm Fe3O4 and 10 nm Au nanoparticles. We optimized the x-ray energy and the sample-to-detector distance to facilitate simultaneous collection of both SAXS and WAXS. We further performed in situ high pressure SAXS and WAXS on a cubic supercrystal assembled from 4 nm wurtzite-structure CdSe nanoparticles. While wurtzite-structure CdSe nanoparticles transform into a rocksalt structure at 6.2 GPa, the cubic superstructure develops into a lamellarlike mesostructure at 9.6 GPa. Nanoparticle coupling and interaction could be enhanced, thus reducing the compressibility of the interparticle spacing above ∼3 GPa. At ∼6.2 GPa, the wurtzite-to-rocksalt phase transformation results in a noticeable drop of interparticle spacing. Above 6.2 GPa, a combined effect from denser CdSe nanoparticle causes the interparticle spacing to expand. These findings could be related to a series of changes including the surface structure, electronic and mechanical properties, and strain distribution of CdSe under pressure. This technique opens the way for exploring the new physics of nanoparticles and self-assembled superlattices.
Magnetic microrheometer for in situ characterization of coating viscosity
Authors: Song Jin-Oh , Henry Robert M. , Jacobs Ryan M. , Francis Lorraine F.
Published: September 2010

A magnetic microrheometer has been designed to characterize the local viscosity of liquid-applied coatings in situ during solidification. The apparatus includes NdFeB magnets mounted on computer-controlled micropositioners for the manipulation of ∼1 μm diameter superparamagnetic particles in the coating. Magnetic field gradients at 20–70 T/m are generated by changing magnet size and the gap distance between the magnets. A specimen stage located between two magnets is outfitted with a heater and channels to control process conditions (temperature and air flow), and a digital optical microscope lens above the stage is used to monitor the probe particle position. Validation studies with glycerol and polyimide precursor solution showed that microrheometry results match traditional bulk rheometry within an error of 5%. The viscosities of polyvinyl alcohol (PVA) solution and polyimide precursor solution coatings were measured at different shear rates (0.01–5 s−1) by adjusting the magnetic field gradient. The effect of proximity to the substrate on the particle motion was characterized and compared with theoretical predictions. The magnetic microrheometer was used to characterize the time-viscosity profile of PVA coatings during drying at several temperatures. The viscosity range measured by the apparatus was 0.1–20 Pa s during drying of coatings at temperatures between room temperature and 80 °C.
Increased low field magnetoresistance in electron doped system Sr0.4Ba1.6−xLaxFeMoO6
Authors: Pandey Vibhav , Verma Vivek , Bhalla G. L. , Kotnala R. K.
Published: September 2010

Magnetotransport properties of electron doped polycrystalline system Sr0.4Ba1.6−xLaxFeMoO6 are presented in this paper. We have observed increased low field magnetoresistance values with significant Curie temperature increase in the electron doped system Sr0.4Ba1.6−xLaxFeMoO6. The low field magnetoresistance value (at 1000 Oe) in 20% La3+ doped sample is observed to be 2.17% at 300 K. At 0.64 T and 80 K, the magnetoresistance change measured in this sample is 21.4%. This sample also showed 50 K increase in Curie temperature over the pristine sample. The increased low field magnetoresistance values are associated with modified grain boundary barriers of the system. The results confirm the fact that the modification of grain boundary barriers has enough potential to possess high low field magnetoresistance values even in the systems with lower spin polarization values. The role of grain to grain connectivity is observed to be dominantly determining the low field magnetoresistance values in grain to grain tunnel type magnetoresistance.
Two-link swimming using buoyant orientation
Authors: Burton L. J. , Hatton R. L. , Choset H. , Hosoi A. E.
Published: September 2010

The scallop theorem posits that a two-link system immersed in a fluid at low Reynolds number cannot achieve any net translation via cyclic changes in its hinge angle. Here, we propose an approach to “breaking” this theorem, based on a static separation between the centers of mass and buoyancy in a net neutrally buoyant system. This separation gives the system a natural equilibrium orientation, allowing it to passively reorient without changing shape.
Helium atom diffraction measurements of the surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces
Authors: Becker James S. , Brown Ryan D. , Johansson Erik , Lewis Nathan S. , Sibener S. J.
Published: September 2010

The surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces were measured using helium atom scattering. The elastic diffraction patterns exhibited a lattice constant of 3.82 Å, in accordance with the spacing of the silicon underlayer. The excellent quality of the observed diffraction patterns, along with minimal diffuse background, indicated a high degree of long-range ordering and a low defect density for this interface. The vibrational dynamics were investigated by measurement of the Debye–Waller attenuation of the elastic diffraction peaks as the surface temperature was increased. The angular dependence of the specular (θi=θf) decay revealed perpendicular mean-square displacements of 1.0×10−5 Å2 K−1 for the CH3–Si(111) surface and 1.2×10−5 Å2 K−1 for the CD3–Si(111) surface, and a He-surface attractive well depth of ∼7 meV. The effective surface Debye temperatures were calculated to be 983 K for the CH3–Si(111) surface and 824 K for the CD3–Si(111) surface. These relatively large Debye temperatures suggest that collisional energy accommodation at the surface occurs primarily through the Si–C local molecular modes. The parallel mean-square displacements were 7.1×10−4 and 7.2×10−4 Å2 K−1 for the CH3–Si(111) and CD3–Si(111) surfaces, respectively. The observed increase in thermal motion is consistent with the interaction between the helium atoms and Si–CH3 bending modes. These experiments have thus yielded detailed information on the dynamical properties of these robust and technologically interesting semiconductor interfaces.
Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer
Authors: Yuasa H. , Hara M. , Murakami S. , Fuji Y. , Fukuzawa H. , Zhang K. , Li M. , Schreck E. , Wang P. , Chen M.
Published: September 2010

We have enhanced magnetoresistance (MR) for current-perpendicular-to-plane giant-magnetoresistive (CPP-GMR) films with a current-confined-path nano-oxide layer (CCP-NOL). In order to realize higher purity in Cu for CCPs, hydrogen ion treatment (HIT) was applied as the CuOx reduction process. By applying the HIT process, an MR ratio was increased to 27.4% even in the case of using conventional FeCo magnetic layer, from 13.0% for a reference without the HIT process. Atom probe tomography data confirmed oxygen reduction by the HIT process in the CCP-NOL. The relationship between oxygen counts and MR ratio indicates that further oxygen reduction would realize an MR ratio greater than 50%.
Many-body and nonequilibrium effects on relaxation oscillations in a quantum-dot microcavity laser
Authors: Lingnau Benjamin , Lüdge Kathy , Schöll Eckehard , Chow Weng W.
Published: September 2010

We investigate many-body and nonequilibrium effects on the dynamical behavior of a quantum-dot laser diode. Simulations, based on the Maxwell-semiconductor-Bloch equations, show strong dependence of the turn-on delay on initial cavity detuning, because of a dynamical shift in the quantum-dot distribution caused by band gap renormalization. Gain switch behavior is found to be insensitive to inhomogeneous broadening, because the balancing between many-body and free-carrier effects inhibits a cavity resonance walk-off. Both the relaxation oscillation damping and frequency are found to increase with decreasing inhomogeneous broadening widths. However, in contrast to bulk and quantum-well lasers, oscillation damping increases less than the frequency.
Inhibited single-electron transfer by electronic band gap of two-dimensional Au quantum dot superlattice
Authors: Xu Rui , Sun Yi , Yang Ji-Yong , He Lin , Nie Jia-Cai , Li Lingling , Li Yadong
Published: September 2010

The electronic density of states of two-dimensional (2D) Au quantum dot superlattice are explored by using cryogenic scanning tunneling microscopy and scanning tunneling spectroscopy. The 2D Au superlattice opens up a gap in its electronic density of states. The single-electron transfer of a single Au quantum dot can be effectively inhibited by this “artificial” forbidden gap. This finding opens a route toward modulating electronic energy band of solid on the basis of 2D metal quantum dot superlattice, which may generate materials with electronic properties for possible future electronic devices.
The TiAl channel mechanism for enhanced (de)hydrogenation kinetics in Mg-based films
Authors: Hao Shiqiang
Published: September 2010

The transport properties of hydrogen in metal additives are very important for understanding the enhanced kinetic processes of (de)hydrogenation in metal hydrides. Based on the first-principles calculations, we found that the H2 dissociation rates on TiAl surfaces are very facile and the dissociated H diffusion in TiAl lattice is much faster than that in host material MgH2. We propose that the “catalytic” effect of additives Ti and Al is the H transport channel within the Mg and MgH2 host materials for the enhanced reaction kinetics.