bluuebunny/crossref_metadata_2025 huggingface dataset:
A new concept for understanding the plastoelasticity of polymers
Authors: Hosemann R. , Loboda‐Čačković J.
Published: June 2010

Chain molecules of partially crystalline polymers are built up as a three‐dimensional network using one part of their chain segments. The other parts of segments of each molecule are embedded in microparacrystals (mPCs). It is pointed out that the random coil concept is nevertheless a good first approximation for the real conformation of a chain molecule. Its straight segments build up the mPCs. They act as the knots of a three‐dimensional network and explain the phenomenon of the affine transformation and retransformation properties of these structures. On this basis, one can develop a rheology which is in accord with the molecular structure. Mechanical models can be applied, which, contrary to those of conventional methods, substantially contribute Kelvin and Maxwell elements to microdomains and not to volume elements. One microdomain contains at least 106 mPCs, including their surrounding network. The positions of the centers of the microdomains obey the rules of affine transformation. They consist of a large number of mPCs. Stretching experiments with linear polyethylene Lupolen 6001H (BASF) are discussed as an example. In the pseudo‐Hooke's law range until elongations of γ ∼ 30%, statistically distributed mPCs in suitable positions are plastically deformed. At longer γ‐values cooperative deformations of layers of mPCs set in and give rise to a necking process. Stretching is thermoreversible under a natural draw ratio because the relaxation time of the Maxwell elements is long enough compared with the time taken for the microdomains to travel through the neck. Their retardation time is calculated and has a minimum value of 2 min, 6 mm behind the beginning of the neck.
Interpretation of light scattering in moderately concentrated polymer solutions
Authors: Dautzenberg H.
Published: June 2010

Light scattering curves of moderately concentrated polymer solution in good solvents show increasing curvature at higher concentrations in the range of small scattering angles. An attempt was made to separate the scattering curves into their intra‐ and intermolecular contributions and draw conclusions concerning the radial distribution function of the molecular centers of gravity in solution. The results obtained suggest the formation of a network of overlapping coils as the structure model for such systems. Model calculations on rotational ellipsoids showed that preferential parallel orientation of coils having no spherical symmetry may offer an explanation for the peculiar behavior of the intra‐ and interparticular scattering functions, which was derived from experimental data.
Investigation of dynamic light scattering in a nematic liquid crystal
Authors: Štěpáanek P. , Sedláček B.
Published: June 2010

Some properties of the dynamic light scattering from an a.c. excited nematic liquid crystal (MBBA) have been interpreted in terms of the de Gennes theory of light scattering by orientation fluctuations.
Theory of light scattering from a system of interacting spherical macromolecules
Authors: Hess W. , Klein R.
Published: June 2010

A nonlinear stochastic transport equation for the concentration fluctuations of interacting macromolecules is derived. This dynamic equation is transformed into a pair of linear equations, and the connection of the solutions to these equations with the light scattering spectrum and an effective diffusion constant are established.
Phase equilibria of polystyrene solutions
Authors: Tager A. A. , Andreeva V. M. , Vshivkov S. A. , Tjukova I. S.
Published: June 2010

The cloud‐point curves for polystyrene (PS) solutions in ethylbenzene, decalin, and cyclohexane have been studied. Investigations of the spinodal for these systems were carried out using the light scattering method proposed by Chu and Scholte. The existence of the upper critical solution temperature polystyrene–for the system ethylbenzene has been demonstrated. For the sample of PS with a narrow molecular mass distribution the cloud‐point curves are binodal. The tops of binodals and spinodals coincide.

From the temperature and angle dependences of light scattering the radius of gyration were calculated using the theory of Debye and of Vrij and Esker.
On the theory of stabilization of dispersions with adsorbed polymer
Authors: Hesselink F. Th.
Published: June 2010

Some aspects of the development of the theory of stabilization of dispersions with adsorbed (anchored) polymer molecules are reviewed. Approximate analytic expressions are derived for the repulsion between both flat particles and spheres. It is shown that the HVO theory (developed by Hesselink, Vrij, and Overbeek) predicts the behavior observed by Napper et al. for latex systems stabilized with anchored polymer. Napper's opposing contention is based on a comparison of experimental observations with theoretical curves, calculated for different experimental conditions. Napper's theoretical and experimental arguments for the omission of the volume restriction term from the interaction equation for particles covered by adsorbed polymers are shown to be invalid. The effect of the size distribution of the adsorbed tails on the steepness of the repulsion curve is demonstrated.

Dolan and Edwards' recently developed theory, which does not involve an artificial split of the free energy into a configurational and a mixing term, is shown to yield results similar to those obtained with the HVO theory.
Crystallization‐induced reactions of copolymers. V. Important reaction variables in the reorganization of random to block copolyesters
Authors: Lenz Robert W. , Schuler Alan N.
Published: June 2010

The effects of reaction parameters including copolyester composition, catalyst type and amount, temperature, time, endgroup concentration (molecular weight), and degree of crystallinity were determined for the reorganization of random to block poly(ethylene terephthalate‐co‐succinate). The crystallization‐induced reactions, which were the basis of these ordering processes, were carried out at temperatures at or below the terephethalate unit melting points of the initial copolyester. All samples so treated showed increased melting points, recrystallization temperatures, and degrees of crystallinity which correlated with increased blockiness of the terephthalate units, as determined by nuclear magnetic resonance spectroscopy. At reaction temperatures greater than 15°C below the initial copolyester melting point, those parameters which controlled the rate of the ester interchange reaction also controlled the extent of the reorganization. Within approximately 15°C of the melting point, the reaction rate was apparently less important than physical factors related to the crystalline properties of the initial copolyester.
Polymerization of vinylpyridinium salts. X. Copolymerization studies of cationicanionic monomer pairs
Authors: Salamone J. C. , Watterson A. C. , Hsu T. D. , Tsai C. C. , Mahmud M. U. , Wisniewski A. W. , Israel S. C.
Published: June 2010

The mechanism of the spontaneous polymerization of vinylpyridinium salts in aqueous and acidic solution has been actively investigated in recent years. Recent reports have suggested that these reactions are free radical in nature. In order to investigate the involvement of free radical initiation in the spontaneous polymerization reactions, an investigation of ion pair copolymers between the cationic 4‐vinylpyridinium moiety and the anionic vinylsulfonate, 2‐acrylamido‐2‐methylpro‐panesulfonate, and p‐styrenesulfonate has been undertaken. The results of spontaneous polymerization suggest that for 4‐vinylpyridinium vinylsulfonate, only the cationic moiety is polymerized, whereas for 4‐vinylpyridinium 2‐acrylamido‐2‐methylpropanesulfonate, two homopolymers or a block copolymer apparently result, and for 4‐vinylpyridinium p‐styrenesulfonate, an alternating copolymer appears to be obtained.
Depolarized rayleigh spectroscopy of rigid macromolecules
Authors: Pecora R.
Published: June 2010

Some applications of depolarized light‐scattering spectroscopy to the study of rigid macromol‐ ecules in solution are described. The depolarized light‐scattering method can be used to obtain ro‐ tational diffusion coefficients and static and dynamic correlation factors of rigid macromolecules. In molecules exhibiting some flexibility, intramolecular conformational relaxation times may also be obtained. Dynamic polarized light‐scattering measurements give the orientation averaged translational diffusion coefficient. With the Perrin relations for spheroids, the rotational and translational diffusion coefficients may be combined to yield the macromolecular solution dimensions. In addition, changes in rigidity and shape of rigid macromolecules may be observed by measuring changes in the depolarized spectrum. For instance, the total depolarized intensity and relaxation time usually decrease when a helical molecule is denatured to a flexible form. The rotational diffusion coefficients obtained by light scattering may also be combined with relaxation times obtained by other techniques such as nuclear magnetic relaxation to draw inferences about molecular rigidity and local motions.
Modification of fibrin by synthetic polymers
Authors: Kovács G. , Fedorova N. , Kiss L. , Killy T.
Published: June 2010

Fibrin‐based resorbable surgical implant material is applied in clinical practice with success. However, its good swelling is a disadvantage in using it for fixing broken bones. To alter the swelling properties of fibrin, chemical modifications were carried out on it by synthetic polymers and polymer reactions. The following modified fibrins were prepared and served as models to study the swelling and enzymatic digestion under in vitro conditions: fibrin with pendant semimaleate groups, with poly(ethylene oxide) and poly(N‐vinyl‐2‐pyrrolidinone) side chains, fibrin‐copoly(ethylene maleic anhydride), and fibrin‐copoly(ethylene maleic acid) polymer substances.
Some chemical aspects of the behavior of synthetic polymers in a living organism
Authors: Lipatova T. E.
Published: June 2010

The problems engendered in the use of polymers for endoprostheses and in glues for tissues are considered. An approach to the solution to the problem through the use of polymers with controllable rates of “resorption” (biodestruction) in the organism and glues for soft tissue is demonstrated.
Anticoagulation activity of some sulfate‐containing polymers of the methacrylate type
Authors: Šorm M. , Nešpurek S. , Mrkvičková L. , Kálal J. , Vorlová Z.
Published: June 2010

A number of synthetic polymers and copolymers of the methacrylate type with a different content of sulfate, sulfamide, and carboxylic groups have been prepared. The anticoagulation activity of polymers thus obtained was compared with that of heparin. The highest anticoagulation activity was found with copolymer II containing 86 mol % of sulfate and 14 mol % of carboxylic groups. A surprisingly weak activity was observed with polymers containing sulfamide groups.
Dissociation and recombination reactions in solid polymers
Authors: Smets G. , Nijst G. , Schmitz‐Smets M. , Somers A.
Published: June 2010

Photochemical and thermal dissociation of labile molecules in the solid state or dissolved in solid polymer matrix affords reaction products which differ in composition and relative amounts from those obtained in solution. These differences are interpreted on the basis of limited rotation and diffusion possibilities. When the dissociation produces reactive species which can recombine thermally or photochemically, the kinetics do not follow a bimolecular reaction mechanism, as in solution experiments. On the contrary, they show a stepwise process, that has been described by Waite, Lebedev, and Butyagin. As a first step, rapid “cage recombination” occurs, followed by a second very slow step corresponding to the diffusion‐controlled recombination of isolated species (radicals or monomers). These stepwise reaction kinetics are illustrated by three different dissociation–recombination equilibria.

a. thermal dissociation of benzpinacol and its derivatives and radical recombination.

b. photochemical dissociation of hexaphenyl‐1.2′‐bisimidazole into triphenyl‐imidazolyl radicals and their recombination.

c. photochemical dissociation of substituted anthracene‐ and (benz)acridizinium dimers and photochemical recombination of monomers In (b), radical pairs and isolated radicals can easily be distinguished by ESR. On the basis of Waite's rate equations, the diffusion coefficient of the radical and the “cage” dimension can be calculated. The cage dimensions agree with these determined by Butyagin for radical decay on γ‐irradiated polymers. Experiments at different temperatures (below and above Tg) stress the influence of the segmental mobility of the polymers, as well as of the molar volume of the labile molecules.
Some observations on the melting behavior of isotactic polypropylene crystals
Authors: Mucha Maria
Published: June 2010

The results of DSC investigations carried out at different heating rates for isotactic polypropylene (IPP) samples with various degrees of morphology and crystallinity have been correlated with the results of SAXS experiments and optical microscopy observations. The SAXS experiments have been performed mainly to calculate the long‐period, thickness of crystalline layers and the degree of crystallinity. The multiple endotherms have been observed for samples crystallized at temperatures higher than 100°C. These endotherms are connected with different crystal types formed during crystallization of IPP. These crystals show superheating phenomena when the heating rate in DSC measurements increases. These effects lead to the conclusion that crystals of larger size and perfection grow in these samples rather than in those crystallized at lower temperatures. The latter ones show reorganization phenomena in DSC measurements. The DSC and SAXS investigations performed for the samples after their thermal oxidation in air at 130°C and in fuming nitric acid have shown the long‐period, thickness of crystalline layers and the degree of crystallinity changes correlated with the melting peak temperature variations. The polymer oxidation in air occurs mainly in the amorphous phase and causes the chain scissions. This effect results in the chain mobility increase and their recrystallization on the lamellae surfaces. At the same time (at sufficiently high temperature) the reorganization of the polymer crystals and the crystal form transformation occur and allow for elucidation of the observed changes in melting temperatures and DSC curves.
Preparation and properties of poly(silarylene siloxane)s
Authors: Koide N. , Lenz R. W.
Published: June 2010

A series of exactly alternating silarylene‐siloxane homopolymers and copolymers was prepared by the step‐growth polymerization reaction of arylenedisilanols with bis(ureido)silanes. The polymers were obtained in high molecular weight and were found to have low glass transition temperatures and excellent thermal stabilities at high temperatures, particularly in an inert atmosphere. Copolymers containing vinylsiloxane units could be filled and crosslinked to form elastomers with useful mechanical properties and resistance to degradation in air at temperatures up to 250°C.
Farben im Metallleichtbau
Authors: Burkhardt Siegfried
Published: June 2010

Auch im Industriebau spielt die Farbe eine wichtige Rolle zur architektonischen Gestaltung eines Gebäudes. Für die Außenhautdieser Bauwerke werden zum großen Teil Elemente aus dem Metallleichtbau verwendet. Bei einem großen Teil dieser Elemente handelt es sich um Sandwichelemente, Bauteile mit dünnen Metalldeckschichten und einem Dämmstoffkern zur Erzielung der Wärmedämmung. Die Deckschalen sind in aller Regel bandbeschichtet und können jede erdenkbare Farbe haben. Im Rahmen der Ursachenforschung von zwei zunächst nicht erklärbaren Schadensfällen wurde festgestellt, dass für die Helligkeit der eingesetzten Farbe der Kunststoffbeschichtungen infolge zweier Messverfahren unterschiedliche Ergebnissen gemessen wurden. Auch die allgemeinen bauaufsichtlichen Zulassungen gaben hierzu keine verlässlichen Angaben. Dies führte dazu, auf diese Messverfahren und vor allem auf die sich daraus ergebenden Schadensmöglichkeiten näher einzugehen.

Colours in light metal construction. Also in the industrial construction the colour plays an important role in the architectural design of a building. For the lining of these buildings light metal elements are used largely. For the most part these elements are sandwich elements, components with thin metal top layers and a core of insulating material to achieve thermal insulation. Usually the top layer is coated and can have any conceivable colour. In the course of investigating two cases of damage, which could not be clarified initially, it was established that the brightness of the plastic‐coatings measured by two different measurement procedures gave different results. In addition the general technical approvals did not provide any reliable statements for this. This led to investigate these measurement methods and above all the possibilities of damage resulting.
Neuartige Cyclopentadienyl‐N‐silylphosphazen‐Komplexe der Seltenerdmetalle Yttrium und Lutetium
Authors: Hillesheim Nina S. , Elfferding Michael , Linder Thomas , Sundermeyer Jörg
Published: June 2010

We report the investigation of four new monoanionic cyclopentadienyl‐N‐silylphosphazene ligands [C5R4‐SiMe2‐NPR′3]– (CpSiNP–) 1–4. In this system the amido moiety of the classical dianionic chelate ligand (CpSiN2–) is displaced by an isoelectronic phosphazene donor function (CpSiNP–). The iminophosphorane‐functionalized tetramethylcyclopentadiene ligands have been prepared by the reaction of two equivalents of tris(tert‐butyl)iminophosphorane or tris(dimethylamino)iminophosphorane with tetramethyl or tert‐butyl‐substituted chlorodimethylsilyl‐1,3‐cyclopentadiene. The molecular structures of the protonated species of two representatives 1‐H and 2‐H were established by X‐ray diffraction analysis. Furthermore the metallation of the ligand [C5R4‐SiMe2‐NPtBu3]H (2‐H) was explored by the aryl elimination pathway using chelate stabilized arene complexes of rare‐earth metals (RE) [RE(dmba)3][RE = Y, Lu; (dmba–) = ortho‐metalated N,N‐dimethylbenzylamine]. The resulting cyclopentadienyl diaryl complexes of the type [(η5‐C5Me4‐SiMe2‐NPtBu3)RE(dmba)2] [RE = Y (5); Lu(6)] were completely characterized by NMR spectroscopy, elemental analysis and X‐ray diffraction analysis. The coordination number of the central atom in each case is nine. Five RE–C bonds to the Cp fragment, two RE–C bonds to the aryl‐carbon atom and two RE–N bonds to the chelating amino function are realized. The phosphazene unit with uncommonly large Si–N–P angles of 173° (5) and 166° (6) do not form a bond in terms of the Constrained‐Geometry ligand concept at least in these complexes. It seems that on the one hand the high coordination number and on the other hand the stable chelate structure of the coordinated amino‐aryl ligand is responsible for this result.
Moist multi-scale models for the hurricane embryo
Authors: MAJDA ANDREW J. , XING YULONG , MOHAMMADIAN MAJID
Published: June 2010

Determining the finite-amplitude preconditioned states in the hurricane embryo, which lead to tropical cyclogenesis, is a central issue in contemporary meteorology. In the embryo there is competition between different preconditioning mechanisms involving hydrodynamics and moist thermodynamics, which can lead to cyclogenesis. Here systematic asymptotic methods from applied mathematics are utilized to develop new simplified moist multi-scale models starting from the moist anelastic equations. Three interesting multi-scale models emerge in the analysis. The balanced mesoscale vortex (BMV) dynamics and the microscale balanced hot tower (BHT) dynamics involve simplified balanced equations without gravity waves for vertical vorticity amplification due to moist heat sources and incorporate nonlinear advective fluxes across scales. The BMV model is the central one for tropical cyclogenesis in the embryo. The moist mesoscale wave (MMW) dynamics involves simplified equations for mesoscale moisture fluctuations, as well as linear hydrostatic waves driven by heat sources from moisture and eddy flux divergences. A simplified cloud physics model for deep convection is introduced here and used to study moist axisymmetric plumes in the BHT model. A simple application in periodic geometry involving the effects of mesoscale vertical shear and moist microscale hot towers on vortex amplification is developed here to illustrate features of the coupled multi-scale models. These results illustrate the use of these models in isolating key mechanisms in the embryo in a simplified content.
Factorising folds for faster functions
Authors: HUTTON GRAHAM , JASKELIOFF MAURO , GILL ANDY
Published: June 2010

The worker/wrapper transformation is a general technique for improving the performance of recursive programs by changing their types. The previous formalisation (A. Gill & G. Hutton, J. Funct. Program., vol. 19, 2009, pp. 227–251) was based upon a simple fixed-point semantics of recursion. In this paper, we develop a more structured approach, based upon initial-algebra semantics. In particular, we show how the worker/wrapper transformation can be applied to programs defined using the structured pattern of recursion captured by fold operators, and illustrate our new technique with a number of examples.
Stability of housekeeping genes and expression of locally produced growth factors and hormone receptors in goat preantral follicles
Authors: Frota Isana M. A. , Leitão Cintia C. F. , Costa José J. N. , Brito Ivina R. , van den Hurk Robert , Silva José R. V.
Published: June 2010

The aim of the present study was to investigate the stability of six housekeeping genes, and the relative expression of growth factors (EGF, GDF-9, BMP-15, VEGF, FGF-2, BMP-6, IGF-1 and KL) and hormone receptors (FSH, LH and GH) in goat preantral follicles. To evaluate to stability of housekeeping genes micro-dissected fresh follicles (150–200 μm) as well as follicles that have been in vitro cultured for 12 days were used. In addition, isolated fresh follicles were used to compare expression of various growth factors and hormone receptors before culture. Both fresh and cultured follicles were subjected to total RNA extraction and synthesis of cDNA. After amplification of cDNA by real-time PCR, the geNorm software program was used to evaluate the stability of glyceraldehyde-2-phosphate dehydrogenase (GAPDH), β-tubulin, β-actin, phosphoglycerokinase (PGK), 18S rRNA, ubiquitin (UBQ) and ribosomal protein 19 (RPL-19). In addition, follicular steady-state levels of mRNA from the various growth factors under study were compared. Results demonstrated that, in goat preantral follicles, UBQ and β-actin were the most suitable reference genes and thus could be used as parameters to normalize data from future in vitro studies. In contrast, 18S RNA appeared the least stable gene among the tested housekeeping genes. Analysis of mRNA for several hypophyseal hormone receptors in fresh preantral follicles showed significantly higher FSH-R mRNA levels than those of LH-R and GH-R, and no difference between GH-R and LH-R mRNA levels. In regard growth factor mRNA expression in goat preantral follicles, EGF mRNA levels appeared significantly lower than those of the other studied growth factors. Increasingly higher relative mRNA levels were observed for GDF-9, BMP-15, BMP-6, FGF-2, VEGF, Kl and IGF-1, successively. In conclusion, UBQ and β-actin are the most stable housekeeping genes in fresh and 12-days cultured caprine preantral follicles. Furthermore, in fresh follicles, high levels of FSH-R mRNA are detected while among eight growth factors, IGF-1 is the most highly expressed and EGF the weakest expressed compound.
U.S. Public Opinion on Torture, 2001–2009
Authors: Gronke Paul , Rejali Darius , Drenguis Dustin , Hicks James , Miller Peter , Nakayama Bryan
Published: June 2010

Many journalists and politicians believe that during the Bush administration, a majority of Americans supported torture if they were assured that it would prevent a terrorist attack. As Mark Danner wrote in the April 2009 New York Review of Books, “Polls tend to show that a majority of Americans are willing to support torture only when they are assured that it will ‘thwart a terrorist attack.’” This view was repeated frequently in both left- and right-leaning articles and blogs, as well as in European papers (Sharrock 2008; Judd 2008; Koppelman 2009; Liberation 2008). There was a consensus, in other words, that throughout the years of the Bush administration, public opinion surveys tended to show a pro-torture American majority.
Understanding Sample Surveys: Selective Learning about Social Science Research Methods
Authors: Currin-Percival Mary , Johnson Martin
Published: June 2010

We investigate differences in what students learn about survey methodology in a class on public opinion presented in two critically different ways: with the inclusion or exclusion of an original research project using a random-digit-dial telephone survey. Using a quasi-experimental design and data obtained from pretests and posttests in two public opinion courses, we test the hypothesis that students who participate in an original survey research project will have a stronger understanding of survey research methods than students who do not. To better assess the effect of the active learning element of the course, we estimate average treatment effects on the students who participated in the original survey project using nearest neighbor matching (Abadie et al. 2004) with student scores on a pretest. We find evidence of modest improvement in learning of survey methods in the course featuring the original survey research project; however, the major finding here is that a course featuring this kind of opportunity appeals to a different kind of student than a course that allows participants to stay closer to the classroom and library instead of the social science research laboratory. This discovery may have important implications for our understanding of the effects of active learning opportunities in other types of elective courses.
LATINO EMPLOYMENT AND RESIDENTIAL SEGREGATION IN METROPOLITAN LABOR MARKETS
Authors: Dickerson vonLockette Niki T. , Johnson Jacqueline
Published: June 2010

The spatial configuration of minorities relative to Whites in a metropolitan area, or residential segregation, has been identified as a significant barrier to access to employment opportunities for racial/ethnic minorities, including Latinos, in metropolitan labor markets. Dominating the research are tests of place stratification models that focus on segregated ethnic enclaves or the mismatch between minority communities and employment opportunities. Both approaches focus on predominantly Latino neighborhoods and communities, but overlook their structural location and isolation in the broader metropolitan labor market. This study examines whether and to what extent structural characteristics of metropolitan labor markets in which Mexicans, Puerto Ricans, and Cubans live and work shape their employment opportunities and whether or not these relationships vary across the three Latino native-origin groups. We utilize a unique dataset of the demographic, employment, educational, occupational, and industrial characteristics of the 95 largest US cities. The analyses feature both OLS regression to ascertain if varying levels of segregation across metropolitan areas in 2000 is associated with different levels of employment for Latinos, and a fixed-effects analysis to determine if changes in these structural factors between 1980 and 2000 within the same labor market affect the employment rates of Latinos in that metropolitan area. We find that segregation has a deleterious effect on Latino men's employment; in cities where segregation is worse, their employment rates are lower, and as the cities that they live in became more segregated over the 20 year period of study, their employment rates decreased.
Crop shortages
Authors: Wolinsky Howard
Published: June 2010

Howard Wolinsky explains how a serious shortage of breeders and breeding programmes at public universities delays the much‐needed application of genomic research in agriculture.
Massing life
Authors: Hunter Philip
Published: June 2010

Philip Hunter analyses how research on biomass and global carbon cycles could contribute to mitigating the effects of increasing levels of CO2 in the atmosphere.
Name of the game
Authors: Jacobs Howy
Published: June 2010

To mark this month's FIFA extravaganza in South Africa, Howy looks at the similarities between the ‘beautiful games’ of football and scientific publishing.
Gabapentin Suppresses Cortical Spreading Depression Susceptibility
Authors: Hoffmann Ulrike , Dileköz Ergin , Kudo Chiho , Ayata Cenk
Published: June 2010

Cortical spreading depression (CSD) is an intense depolarization wave implicated in the pathophysiology of brain injury states and migraine aura. As Cav2.1 channels modulate CSD susceptibility, we tested gabapentin, which inhibits Cav2.1 through high-affinity binding to its α2δ subunit, on CSD susceptibility in anesthetized rats. Gabapentin, 100 or 200 mg/kg, elevated the electrical threshold for CSD and diminished recurrent CSDs evoked by topical KCl, when administered 1 hour before testing. With its favorable safety and tolerability profile, gabapentin may have a role in suppression of injury depolarizations in stroke, intracranial hemorrhage, and traumatic brain injury.
In situ tunneling measurements in a transmission electron microscope on nanomagnetic tunnel junctions
Authors: Lau J. W. , Morrow P. , Read J. C. , Höink V. , Egelhoff W. F. , Huang L. , Zhu Y.
Published: June 2010

We showed that a chain of nanomagnetic tunnel junctions (MTJs) devices can be electrically addressed individually, in situ, in a transmission electron microscope, such that transport properties can be in principle, quantitatively correlated with each device’s defects and microstructure. A unique energy barrier was obtained for each device measured. Additionally, in situ tunneling magnetoresistance (TMR) measurements were obtained for a subset of devices. We found that TMR values for our nano-MTJs were generally smaller than TMR in the unpatterned film.
Heating dynamics and extreme ultraviolet radiation emission of laser-produced Sn plasmas
Authors: Yuspeh S. , Sequoia K. L. , Tao Y. , Tillack M. S. , Burdt R. A. , Najmabadi F.
Published: June 2010

The impact of 1.064 μm laser absorption depth on the heating and in-band (2% bandwidth) 13.5 nm extreme ultraviolet emissions in Sn plasmas is investigated experimentally and numerically. In-band emission lasting longer than the laser pulse and separation between the laser absorption and in-band emission region are observed. Maximum efficiency is achieved by additional heating of the core of the plasma to allow the optimal temperature to expand to a lower and more optically thin density. This leads to higher temperature plasma that emits less in-band light as compared to CO2 produced plasma sources for the same application.
Wigner crystallization due to electrons localized at deep traps in two-dimensional amorphous dielectric
Authors: Shaimeev S. S. , Gritsenko V. A. , Wong Hei
Published: June 2010

We calculated the spatial distribution of electrons localized at deep neutral traps in some amorphous dielectric films based on some fundamental physics in order to explain the phenomena such as space ordering of electrons. We showed that when the surface density of traps (Ns) is much larger than that of the trapped electrons (ns), e.g., ns/Ns≤0.001, Wigner crystallization occurs due to the Coulomb repulsion of trapped electrons and a two-dimensional quasiperiodic hexagonal lattice or Wigner glass can be formed.
Magnified hard x-ray image in one dimension
Authors: Britten James , Feng Zhechuan , Xu Gu
Published: June 2010

The possibility of magnified x-ray imaging is explored, by the near-field attenuation of a sample intercepting a spherical wave-front, plus the beam profile modulation by Borrmann pyramid based on dynamic x-ray scattering. It is verified by experiments in one dimension as well as numerical simulation.
Coded T-mark continuums: a graphical method for reporting rangeland monitoring data
Authors: Bastin Gary N. , Ludwig John A. , Richardson Kate
Published: June 2010

In this paper we describe a new method of graphically presenting rangeland monitoring data as coded time-mark continuums. This method aims to provide people with an interest in rangelands (stakeholders) with succinct information, which they need to assess rangeland condition and change. This new method graphs data for indicators of rangeland condition as time or T-marks along gradients or continuums. The ends of these continuums are reference points, which are values for indicators defining highly functional to very dysfunctional rangeland systems. The T-marks for an indicator along its continuum are also coded as to how changes relate to combinations of recent seasonal conditions and longer-term management effects. Codes are based on a two-way matrix combining ‘seasonal quality’ (e.g. rainfall in a specified period relative to the long-term record) and expected responses from land management (i.e. increase, decrease or no change relative to that predicted from seasonal quality). Monitoring data available in the Australian Collaborative Rangeland Information System were used to illustrate the use of coded T-mark continuums. We show succinctly how one indicator changed in two different rangeland regions and how multiple indicators changed within one region.
Subgenomic messenger RNA amplification in coronaviruses
Authors: Wu Hung-Yi , Brian David A.
Published: June 2010

Coronaviruses possess the largest known RNA genome, a 27- to 32-kb (+)-strand molecule that replicates in the cytoplasm. During virus replication, a 3′ coterminal nested set of five to eight subgenomic (sg) mRNAs are made that are also 5′ coterminal with the genome, because they carry the genomic leader as the result of discontinuous transcription at intergenic donor signals during (−)-strand synthesis when templates for sgmRNA synthesis are made. An unanswered question is whether the sgmRNAs, which appear rapidly and abundantly, undergo posttranscriptional amplification. Here, using RT-PCR and sequence analyses of head-to-tail–ligated (−) strands, we show that after transfection of an in vitro–generated marked sgmRNA into virus-infected cells, the sgmRNA, like the genome, can function as a template for (−)-strand synthesis. Furthermore, when the transfected sgmRNA contains an internally placed RNA-dependent RNA polymerase template-switching donor signal, discontinuous transcription occurs at this site, and a shorter, 3′ terminally nested leader-containing sgmRNA is made, as evidenced by its leader–body junction and by the expression of a GFP gene. Thus, in principle, the longer-nested sgmRNAs in a natural infection, all of which contain potential internal template-switching donor signals, can function to increase the number of the shorter 3′-nested sgmRNAs. One predicted advantage of this behavior for coronavirus survivability is an increased chance of maintaining genome fitness in the 3′ one-third of the genome via a homologous recombination between the (now independently abundant) WT sgmRNA and a defective genome.
c-Ret–mediated hearing loss in mice with Hirschsprung disease
Authors: Ohgami Nobutaka , Ida-Eto Michiru , Shimotake Takashi , Sakashita Naomi , Sone Michihiko , Nakashima Tsutomu , Tabuchi Keiji , Hoshino Tomofumi , Shimada Atsuyoshi , Tsuzuki Toyonori , Yamamoto Masahiko , Sobue Gen , Jijiwa Mayumi , Asai Naoya , Hara Akira , Takahashi Masahide , Kato Masashi
Published: June 2010

A significantly increased risk for dominant sensorineural deafness in patients who have Hirschsprung disease (HSCR) caused byendothelin receptor typeBandSOX10has been reported. Despite the fact that c-RETis the most frequent causal gene of HSCR, it has not been determined whether impairments of c-Retand c-RETcause congenital deafness in mice and humans. Here, we show that impaired phosphorylation of c-Ret at tyrosine 1062 causes HSCR-linked syndromic congenital deafness in c-Retknockin (KI) mice. The deafness involves neurodegeneration of spiral ganglion neurons (SGNs) with not only impaired phosphorylation of Akt and NF-κB but decreased expression of calbindin D28k in inner ears. The congenital deafness involving neurodegeneration of SGNs in c-RetKI mice was rescued by introducing constitutively activated RET. Taken together with our results for three patients with congenital deafness with c-RET–mediated severe HSCR, our results indicate that c-Retand c-RETare a deafness-related molecule in mice and humans.
Histaminergic responses by hypothalamic neurons that regulate lordosis and their modulation by estradiol
Authors: Dupré Christophe , Lovett-Barron Matthew , Pfaff Donald W. , Kow Lee-Ming
Published: June 2010

How do fluctuations in the level of generalized arousal of the brain affect the performance of specific motivated behaviors, such as sexual behaviors that depend on sexual arousal? A great deal of previous work has provided us with two important starting points in answering this question: (i) that histamine (HA) serves generalized CNS arousal and (ii) that heightened electrical activity of neurons in the ventromedial nucleus of the hypothalamus (VMN) is necessary and sufficient for facilitating the primary female sex behavior in laboratory animals, lordosis behavior. Here we used patch clamp recording technology to analyze HA effects on VMN neuronal activity. The results show that HA acting through H1 receptors (H1R) depolarizes these neurons. Further, acute administration of estradiol, an estrogen necessary for lordosis behavior to occur, heightens this effect. Hyperpolarization, which tends to decrease excitability and enhance inhibition, was not affected by acute estradiol or mediated by H1R but was mediated by other HA receptor subtypes, H2 and H3. Sampling of mRNA from individual VMN neurons showed colocalization of expression of H1 receptor mRNA with estrogen receptor (ER)-α mRNA but also revealed ER colocalization with the other HA receptor subtypes and colocalization of different subtypes with each other. The latter finding provides the molecular basis for complex “push-pull” regulation of VMN neuronal excitability by HA. Thus, in the simplest causal route, HA, acting on VMN neurons through H1R provides a mechanism by which elevated states of generalized CNS arousal can foster a specific estrogen-dependent, aroused behavior, sexual behavior.
On nearly commutative nodal algebras in characteristic zero
Authors: Rich Michael
Published: June 2010

In this paper we consider algebras satisfying the identity (I)

x
(
x
y
)
+
(
y
x
)
x
=
2
(
x
y
)
x

x(xy) + (yx)x = 2(xy)x

and show that there are no nodal algebras of this type over any field

F
F

of characteristic zero. The proof is obtained by first showing that if

x
x

is an element of a finite-dimensional algebra satisfying (I) over a field of characteristic zero then the operator

L
(
x
)
−
R
(
x
)

L(x) - R(x)

is nilpotent.
Zeros of analytic functions with infinitely differentiable boundary values
Authors: Caughran James G.
Published: June 2010

A necessary and sufficient condition is proved that a set of points

{

r
n

e

i
θ
n

}

\{ {r_n}{e^{i\theta n}}\}

in the unit disk be the set of zeros of an analytic function with infinitely differentiable boundary values for every choice of

{

r
n

}
,

0
>

r
n

>
1

and

∑

(
1
−

r
n

)
>
∞

\{ {r_n}\} ,\;0 > {r_n} > 1\;{\text {and}}\;\sum {(1 - {r_n}) > \infty }
Boundedness and dimension for weighted average functions
Authors: Stanford David P.
Published: June 2010

The paper considers a weighted average property of the type
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u left-parenthesis x Subscript o Baseline right-parenthesis equals left-parenthesis integral Underscript upper B Endscripts u w d x right-parenthesis slash left-parenthesis integral Underscript upper B Endscripts w d x right-parenthesis">

u
(

x
o

)
=
(

∫
B

u
w
d
x
)

/

(

∫
B

w
d
x
)

u({x_o}) = ({\smallint _B}uwdx)/({\smallint _B}wdx)

,

B
B

a ball in

E
n

{E^n}

with center

x
o

{x_o}

. A lemma constructing such functions is presented from which it follows that if

n
=
1

n = 1

and the weight function

w
w

is continuously differentiable but is not an eigenfunction of the

1
1

-dimensional Laplace operator, then

u
u

is constant. It is also shown that if

w
w

is integrable on

E
n

{E^n}

and

u
u

is bounded above or below,

u
u

is constant.
Taut and tight complex manifolds
Authors: Barth Theodore J.
Published: June 2010

Taut and tight manifolds, introduced recently by H. Wu, are characterized as follows. Let

D
D

denote the open unit disk in

C
C

. The complex manifold

N
N

is taut iff the set

A
(
D
,
N
)

A(D,N)

of holomorphic maps from

D
D

into

N
N

is a normal family. If

d
d

is a metric inducing the topology on

N
,
(
N
,
d
)

N,(N,d)

is tight iff

A
(
D
,
N
)

A(D,N)

is equicontinuous. It is also shown that every taut manifold is tight in a suitable metric.
Overconvergence and (𝐶,1) summability
Authors: Drobot Vladimir
Published: June 2010

It is shown that a power series can be diluted to become

(
C
,
1
)

(C,1)

summable outside the radius of convergence if and only if it overconverges.
On the uniqueness of solutions of certain improperly posed problems.
Authors: Sigillito Vincent G.
Published: June 2010

Conditions are derived for uniqueness of solutions of some improperly posed problems for hyperbolic equations. Uniqueness results for backward parabolic problems are also included.
Quasi-projective covers and direct sums
Authors: Koehler Anne
Published: June 2010

In this paper

R
R

denotes an associative ring with an identity, and all modules are unital left

R
R

-modules. It is shown that the existence of a quasi-projective cover for each module implies that each module has a projective cover. By a similar technique the following statements are shown to be equivalent: 1.

R
R

is semisimple and Artinian; 2. Every finitely generated module is quasi-projective; and 3. The direct sum of every pair of quasi-projective modules is quasi-projective. Direct sums of quasi-injective modules are also investigated.
Subdirect sums, hereditary radicals, and structure spaces
Authors: Heinicke A. G.
Published: June 2010

If a ring

K
K

is subdirectly embedded into the product

S
S

of a finite number of rings by a mapping

i
i

, then it is proved that

i
(
H
(
K
)
)
=
i
(
K
)
∩
H
(
S
)

i(H(K)) = i(K) \cap H(S)

for any hereditary radical

H
H

, and that any structure space of

K
K

has the topology of a quotient space of a structure space of

S
S

.
The peak sets of 𝐴^{𝑚}
Authors: Taylor B. A. , Williams D. L.
Published: June 2010

Let

A
A

denote the algebra of functions analytic for

|

z

|

>
1

|z| > 1

and continuous for

|

z

|

≦
1

|z| \leqq 1

. For

m
=
1
,
2
,
⋯
,

m = 1,2, \cdots ,

, let

A
m

{A^m}

be the algebra of functions

f
f

such that

f
,

f
′

,
⋯
,

f

(
m
)

∈
A

f,f’, \cdots ,{f^{(m)}} \in A

; and let

A
∞

=

∩

m
=
1

∞

A
m

{A^\infty } = \cap _{m = 1}^\infty {A^m}

. We show that the peak sets of

A
m

,
1
≦
m
≦
∞

{A^m},1 \leqq m \leqq \infty

, are the finite subsets of

{

|

z

|

=
1
}

\{ |z| = 1\}

.
An invariance principle for reversed martingales
Authors: Loynes R. M.
Published: June 2010

Let

X
n

,

n
=
1
,
2
,
⋯

{X_n},\;n = 1,2, \cdots

, be a reversed martingale with zero mean and for each

n
n

construct a random function

W
n

(
t
)

{W_n}(t)

,

0
≦
t
≦
1

0 \leqq t \leqq 1

, by a suitable method of interpolation between the values

X
k

/

(
E

X
n
2

)

1

/

2

{X_k}/{(EX_n^2)^{1/2}}

at times

E

X
k
2

/

E

X
n
2

EX_k^2/EX_n^2

; these are the natural times to use. Then it is shown that the distribution of

W
n

{W_n}

(in function space

C
C

or

D
D

) converges weakly to that of the Wiener process, if the finite-dimensional distributions converge appropriately. It is also shown that the sufficient conditions recently given by the author for the central limit theorem for such martingales also imply convergence of finite-dimensional distributions. Illustrations of the use of these results are given in applications to

U
U

statistics and sums of independent random variables. A result for forward martingales exactly analogous to the first result above is also given, but is given no emphasis.
An 𝑚-orthocomplete orthomodular lattice is 𝑚-complete
Authors: Holland Samuel S.
Published: June 2010

We call an orthomodular lattice

L

m

\mathcal {L}\;m

-orthocomplete for an infinite cardinal

m
m

if every orthogonal family of

≦
m

\leqq m

elements from

L

\mathcal {L}

has a join in

L

\mathcal {L}

, and we call

L

m

\mathcal {L}\;m

-complete if every family, orthogonal or not, of

≦
m

\leqq m

elements from

L

\mathcal {L}

has a join in

L

\mathcal {L}

. We prove that an

m
m

-orthocomplete orthomodular lattice is

m
m

-complete. Since a Boolean algebra is a distributive orthomodular lattice, we obtain as a special case the Smith-Tarski theorem: An

m
m

-orthocomplete Boolean algebra is

m
m

-complete.
Representation of abelian groups and rings by families of real-valued functions
Authors: Kohls Carl W.
Published: June 2010

Sufficient conditions are indicated for the existence of an isomorphism of an abelian group or ring into the family of real-valued continuous functions on a realcompact or compact space. The spaces consist of sets of subsemigroups or subsemirings that are maximal among those containing a fixed element but not containing its additive inverse; in the ring case, where the element is the multiplicative identity, these are just infinite primes in the sense of Harrison. Earlier results of Harrison, Kadison, and Krivine follow from the present discussion.
The converse of Cauchy’s theorem for arbitrary Riemann surfaces
Authors: Goldstein Myron
Published: June 2010

In this paper, we prove a generalization of the converse of Cauchy’s theorem which is valid for arbitrary hyperbolic Riemann surfaces. The tools used are the Kuramochi compactification and the concept of generalized normal component.
Linear perturbations of ordinary differential equations
Authors: Strauss Aaron , Yorke James A.
Published: June 2010

We present several results dealing with the problem of the preservation of the stability of a system

x
′

=
A
(
t
)
x

x’ = A(t)x

which is subject to linear perturbations

B
(
t
)
x

B(t)x

, or to perturbations dominated by linear ones.
Fredholm Toeplitz operators
Authors: Douglas R. G. , Sarason Donald
Published: June 2010

Whether a Toeplitz operator on

H
2

{H^2}

is Fredholm is shown to depend only on the local behavior of the inducing function.
On abstract Pruefer transformations
Authors: Benson Donald C. , Kreith Kurt
Published: June 2010

The Pruefer transformation has been generalized to matrix differential equations by John Barrett, and Barrett’s results have been partly extended to the case of functions which take values in a

B
∗

{B^ \ast }

-algebra by Einar Hille. By modifying Barrett’s proof, generalizations in the

B
∗

{B^ \ast }

-algebra case become possible.
Multiplicative properties of Jensen measures
Authors: Itô Takasi , Schreiber Bert M.
Published: June 2010

It is shown that if

ψ
\psi

is a linear functional on a function algebra with

ψ
(
1
)
=
1

\psi (1) = 1

, and if

ψ
\psi

satisfies the Jensen inequality with respect to some finite nonnegative measure, then

ψ
\psi

is multiplicative.
Countable connected spaces
Authors: Miller Gary Glenn
Published: June 2010

Two pathological countable topological spaces are constructed. Each is quasimetrizable and has a simple explicit quasimetric. One is a locally connected Hausdorff space and is an extension of the rationals. The other is a connected space which becomes totally disconnected upon the removal of a single point. This space satisfies the Urysohn separation property—a property between

T
2

{T_2}

and

T
3

{T_3}

—and is an extension of the space of rational points in the plane. Both are one dimensional in the Menger-Urysohn [inductive] sense and infinite dimensional in the Lebesgue [covering] sense.