bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of pressure and temperature upon the viscosities of liquids with special reference to polymeric liquids
Authors: Cogswell F. N. , McGowan J. C.
Published: March 2007

From a consideration of the work required for expansion of a liquid, the following relationship between viscosity η, pressurePand temperatureTis put forward.

magnified image

For unassociated liquids with molecules which are not too large,V* is taken as the parachor, log10(η* in Ns/m2) is −3.88,P* is 8.58 × 106N/m2,Ris the gas constant, andT* is a constant characteristic of each liquid. The equation can be applied to polymeric liquids ifV* and η* are taken as disposable constants. For example, for polystyreneV* is found to be 3 × 10−3m3mol−1and log10(η* in Ns/m2) to be 3.4 log10M̄w−10.2 whereM̄wis the weight‐average molecular weight (kg/mol) from 5 kg/mol upwards. In the equation, the same constants serve for the variation of viscosity with pressure and with temperature. The viscosity under a high pressure can therefore be estimated from viscosities all measured at normal pressures but at different temperatures. The viscosities of a number of polymers have been measured over a range of temperature and pressure and the results support the equation. Support is found for the view that segments are involved in the flow of polymeric liquids andV* gives a measure of the volume of the segment. The size of the segment seems to increase as the flexibility of the polymer chain decreases. The lowest values forV* are found for polysiloxanes in which the segment seems to be only four atoms long. Larger values ofV* are found for polymers with units of the type –CH2–CHR‐. Larger values still ofV* are given by polymers with units of the type –CH2‐CR1R2‐ and even largerV* values are found for those polymers with benzene rings constituting a major part of the main chain. AsV* rises the viscosity of the polymeric liquid becomes much more dependent upon pressure and temperature. Thus whilst the polysiloxanes have viscosities which are relatively insensitive to pressure and temperature, the aromatic polysulphones and poly(2,6‐dimethylphenylene oxide) have viscosities which are very sensitive to pressure and temperature.
Application of europium and praseodymium shift reagents to the n.m.r. spectra of polymers
Authors: Katritzky A. R. , Smith A.
Published: March 2007

The use of Eu(fod)3 and Pr(fod)3 shift reagents for the investigation of the nuclear magnetic resonance spectra of polymers is reported for the following samples: poly(vinyl methyl ether), poly(vinyl ethyl ether), poly(vinyl acetate) and poly‐(propylene oxide).
Principles of action of polymeric flocculants
Authors: Kitchener J. A.
Published: March 2007

The relationship of flocculation by water‐soluble polymers to the classical phenomena of colloid chemistry is pointed out and the contributions of electrostatic and non‐electrostatic forces are discussed.

Modern flocculants have a high degree of polymerization (e.g. c. 50 000) and an extremely extended configuration when dissolved in a favourable solvent; this factor explains qualitatively some of the peculiarities of flocculation by polymers and indicates the need for rational control of their use if optimum results are to be achieved. It is concluded, however, that a quantitative theory of specific flocculant systems is not possible at present.

Future developments in flocculation technology will almost certainly include introduction of cheaper or more selective flocculants, improved control through the use of auxiliary reagents and more sophisticated consideration of the surface chemistry of materials that have to be flocculated.
Modern experimental methods for the observation of the far infrared spectra of polymers
Authors: Chantry G. W. , Fleming J. W.
Published: March 2007

The introduction of very sensitive detectors and the use of phase modulation has enabled interferometric spectroscopy to be extended downwards in frequency until the spectral coverage overlaps that provided by microwave dielectric methods. The radiometric precision available has been steadily improved by taking advantage of both instrumental and computational advances and the accuracy which can now be attained is comparable to that of dielectric or mid‐infrared methods. Both the real and the imaginary components of the complex dielectric constant (or the complex refractive index) can now be obtained for moderately transparent materials over the millimetre and submillimetre bands for a wide range of specimen temperature, and reflectance methods have been developed for the study of heavily absorbing specimens. The far infrared band is particularly appropriate for the study of high polymers. With these instrumental innovations considerable advances may be expected in the understanding of molecular motion in these materials.
Structure and permeability of porous films of poly(hydroxy ethyl methacrylate)
Authors: Haldon R. A. , Lee B. E.
Published: March 2007

Porous films of poly(hydroxy ethyl methacrylate) have been made by photo‐polymerisation of solutions of the monomer. The permeability of homogeneous films depends on the cross‐link density and the concentration and composition of the polymerisation solvent. A membrane of minimum water permeability, in which the transport mechanism is principally diffusion, results from a cross‐link concentration of ∼9.4 mol‐% and a monomer concentration of ∼75% in an aqueous ethylene glycol solvent (20% ethylene glycol).

More porous (macroporous) films were prepared by first cooling the solution such that the solvent freezes and the monomer occupies the interstices between the solvent crystals. After polymerisation and removal of the solvent, a porous structure results. The rate of freezing, the profile of the thermal gradient, and the solvent and crosslinker concentrations control the permeability of this film. Slow cooling gives random pores (K ≃6 × 10−15 cm2), but rapid, directional cooling from one face gives oriented pores with K ≃10−12 cm2. A 6‐order change in K results from varying the monomer concentration from 40 to 85% in a 4:1 water: ethylene glycol solvent, and a 3‐order change from increasing the ethylene glycol content of the solvent from 0 to 40% at a fixed monomer concentration.
Stabilisation of polyacrylonitrile by oxidative transformation
Authors: Johnson J. W. , Potter W. , Rose P. G. , Scott G.
Published: March 2007

The changes occurring during the heat treatment of polyacrylonitrile polymers in the presence of air up to 350 °C have been examined using both physical and chemical techniques. It is concluded that substantial oxidation does not occur until the polymer has been converted to a ladder structure containing readily oxidisable methylene groups. The development of the highly characteristic physical behaviour of the oxidised polymer, notably absence of melting and hydrophilicity, is associated with the formation of a strongly hydrogen bonded polydihydropyrid‐4‐one structure which acts as an internal restraint to molecular motion and permits the orientation of the parent polymer to be carried through to the higher temperature pyrolysed carbon fibre.
Dielectric Properties of Styrene—Butadiene Rubber/Silicon Dioxide Mixtures
Authors: Hanna Faika F. , Yehia Abbas A. , Abou‐Bakr Abdel‐Fattah
Published: March 2007

The dielectric constant ϵ′ and dielectric loss ϵ″ have been investigated for SBR samples vulcanized with TMTD and loaded with silica in increasing quantities in the frequency range from 60 Hz to 108 Hz at room temperature. Also, the physico‐mechanical properties of these samples have been investigated.

The results of ϵ′ and ϵ″ are analysed using the Cole—Cole method. Two absorption regions are found: a low frequency absorption region with a maximum at about 10 kHz which is attributed to Maxwell—Wagner effect and a high frequency absorption region with a maximum at 107 Hz which is due to the orientation of polar groups. A third absorption region appeared at frequencies below 100 Hz and may be due to absorption of moisture arising from the presence of silica in the sample.
Structure of the cobalt drier complex
Authors: O'Neill Leonard A. , Falla Norman A. R.
Published: March 2007

Cobalt octoate (2‐ethyl hexoate) has been studied by a wide range of spectroscopic and physical techniques and found to be polymeric. A structure for the compound is proposed. Its activity as a drier in a surface coating medium is shown to be related to its polymeric state and to the coordinating effect of other components present in the system. Auxiliary metals such as calcium or lead enhance the activity by providing a strong ligand field around the cobalt, facilitating the transition from the cobaltous to cobaltic state. Other metals such as zinc or tin, or polyols reduce the activity by coordination to configurations unfavourable to this change.
Reactions of Wheland complexes: base catalysis in re‐aromatization reaction of σ complexes obtained from 1,3,5‐tris(N,N‐dialkylamino)benzene and arenediazonium salts
Authors: Forlani Luciano , Boga Carla , Del Vecchio Erminia , Ngobo Aline‐Laure Tocke Dite , Tozzi Silvia
Published: March 2007

The usual idea on the two‐steps mechanism of aromatic electrophilic substitution reactions is that the first step (the attack of the electrophilic reagent on the activated substrate) is rate limiting, while the driving force of the reaction is the fast proton departure to recover the resonance energy of the aromatic substrate. The now examined systems allow the formation of stable σ cationic complexes (Wheland intermediates) which may be investigated by simple procedures. Data here reported represent a clear and simple instance of a measurement of the rate of the proton abstraction from a Wheland intermediate and they indicate that this proton abstraction occurs by base catalysis in a rate determining step. Probably, this feature is more frequent than that usually conceived in the mechanism of electrophilic aromatic substitution reactions, because these reactions are often carried out in reaction mixtures containing large amounts of proton acceptor species which might mask the possible base catalysis. Copyright © 2007 John Wiley & Sons, Ltd.
Triplet state and phenoxyl radical formation of 3, 4‐methylenedioxy phenol: a combined laser flash photolysis and pulse radiolysis study
Authors: Joshi Ravi , Kapoor S. , Mukherjee T.
Published: March 2007

Formations of triplet state, molecular cation radical, and phenoxyl radical of 3,4‐methylenedioxy phenol (sesamol, SOH) in organic solvents have been investigated by laser photolysis as well as pulse radiolysis techniques. Photolysis of SOH in cyclohexane has been found to produce both triplet state (λmax ∼ 480 nm) and phenoxyl radical (425–430 nm) of SOH by mono‐photonic processes. However, radical cation (λmax = 450 nm) and phenoxyl radical of SOH have been observed on radiolysis in cyclohexane. Further, radiolysis of SOH in benzene has been found to produce phenoxyl radical only. Mechanism of phenoxyl radical formation by photo‐excitation of SOH has been studied and triplet energy level of SOH is estimated to lie between 1.85 and 2.64 eV. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of temperature, ration, body size and age on sulphur isotope fractionation in fish
Authors: Barnes Carolyn , Jennings Simon
Published: March 2007

Sulphur isotope analysis (δ34S) is increasingly identified as a valuable tool for source differentiation and the determination of trophic level in food webs, but there are still many uncertainties associated with the interpretation of δ34S data. To investigate the effects of temperature, ration, body size and age on sulphur trophic fractionation (Δδ34S) in fish, we reared European sea bass (Dicentrarchus labrax) on identical diets at 11 and 16°C at three ration levels for over 600 days. Δδ34S was between 0 and −1‰. The effect of temperature on Δδ34S was small and inconsistent, varying over the course of the experiment and depending on ration. This contrasts with temperature effects on bass Δδ13C and Δδ15N, where Δδ13C increases at warm temperatures while Δδ15N falls. Body size and age had a positive relationship with Δδ34S but the relationship with size was not significant for bass that weighed >20 g. As Δδ34S is small and the range in δ34S of potential diet items can be much greater than the range in δ13C or δ15N, our results show that sulphur stable isotopes are particularly useful for source differentiation in fish. Copyright © 2007 John Wiley & Sons, Ltd.
Resolution of infrared matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry using glycerol; enhancement with a disperse laser beam
Authors: Cha Hyun Jung , Moon Jeong Hee , Kim Myung Soo
Published: March 2007

Some experimental factors affecting the resolution in glycerol infrared matrix‐assisted laser desorption/ionization (IR‐MALDI) time‐of‐flight (TOF) mass spectrometry were investigated. Loading the sample inside a cavity covered with a grid was found to improve the resolving power as reported previously, although not to the extent attainable in UV‐MALDI using the same instrument. The resolving power improved as the laser spot area at the sample position got larger, becoming almost comparable with that in UV‐MALDI when the spot area was a little larger than the cavity size. Reduced concentration of the ablated materials in the acceleration region with the use of the grid and large irradiation area may be responsible for the enhanced resolution. In addition, the threshold laser fluences measured in this work were lower than those reported in the literature and tended to decrease more rapidly as the irradiation area increased than predicted previously. The implication of similar threshold fluences for matrix and analyte ions is discussed in relation to the analyte ion formation mechanism. Copyright © 2007 John Wiley & Sons, Ltd.
Erweiterung der DASt‐Richtlinie 009 für die Stahlgütewahl bei Einschubverbindungen im Hochbau
Authors: Höhler Susanne , Sedlacek Gerhard
Published: March 2007

Die DASt‐Richtlinie 009, äquivalent mit DIN EN 1993‐1‐10, liefert ein auf der Bruchmechanik basierendes Verfahren zur Stahlgütewahl für Stahlbauten zur Vermeidung von Sprödbruch bei niedrigen Temperaturen. Dieses Verfahren ist ursprünglich für die Bedingungen des Brückenbaus, d.h. für ermüdungswirksame Belastungen abgeleitet worden und gilt für alle Kerbdetails, die in DIN EN 1993‐1‐9 oder im DIN‐Fachbericht 103 enthalten sind. Bei Anwendung solcher Kerbdetails liegt die Stahlgütewahl auch im Hochbau auf der sicheren Seite. Wirtschaftliche Hochbauverbindungen, z. B. Einschubverbindungen, beruhen auf plastischen Bemessungsmodellen und sind nicht kerbfallorientiert gestaltet. Daher fallen sie nicht in den Gültigkeitsbereich der DASt‐RiL 009.

Der vorliegende Beitrag liefert einen Vorschlag für die Erweiterung der DASt‐Richtlinie 009, mit der auch für Einschubverbindungen die Stahlgütewahl durchgeführt werden kann. Dabei wird ähnlich wie im Brückenbau vorgegangen, jedoch werden die Eingangsgrößen für den bruchmechanischen Nachweis (z. B. Rißgrößen) ersetzt. Die vereinfachten Tabellen sind ähnlich gestaltet wie in der DASt‐RiL 009, allerdings haben neben der Blechdicke auch die geometrischen Parameter des Blechausschnitts einen Einfluß.
Reflection and transmission coefficients for water wave scattering by a sea‐bed with small undulation
Authors: Martha S.C. , Bora S.N.
Published: March 2007

The scattering of a train of progressive waves by a small undulation of the bottom of a laterally unbounded sea is considered with two dimensional linear water wave theory. Assuming irrotational motion, a simplified perturbation analysis is employed to obtain the first order corrections to the velocity potential by using the Green's integral theorem in a suitable manner and also to the reflection and transmission coefficients in terms of integrals involving the shape of the function $c(x)$ representing the bottom undulation. Two particular forms of the shape function are considered and the integrals for reflection and transmission coefficients are evaluated for these shape functions. Out of these two cases, we focus mainly on a patch of sinusoidal ripples at the bottom and find that the reflection coefficient up to the first order is an oscillatory function of β which is twice the ratio of the wave numbers of the wave and the ripple bed. When this ratio becomes 0.5, i.e., when β = 1 (the situation when Bragg resonance occurs), the reflection coefficient becomes a multiple of the number of ripples, and high reflection of the incident wave energy occurs if this number is large. We present the result in graphical form for one, two, and six ripple(s) in the patch. The results find absolute agreement with available results. We also show the graphical comparison of the reflection coefficient against the wave number for one, three, and five ripple(s).
A wavelet‐based location referencing strategy for digital maps in navigation systems
Authors: Zangmeister T. , Sonar Th. , Heßling M.
Published: March 2007

One of the main problems of modern navigation systems for cars is location referencing, i.e. the description of a certain location in a digital map ‘A’ and the search of exactly this location in a different digital map ‘B’. In contrast to classical methods of finding a location by means of the surrounding geometry or even the use of attributes like names and types of streets, we propose a purely analytical approach based on the wavelet transform of the digital maps themselves.
Bio‐economic resource management under threats of environmental catastrophes
Authors: Tsur Yacov , Zemel Amos
Published: March 2007

We combine ecological and economic dynamics to study the management of a natural resource that supports both ecosystem and human needs. Shrinking the resource base introduces a threat of occurrence of catastrophic ecological events, such as sudden ecosystem collapse. The occurrence conditions involve uncertainty of various types, and the distinction among these types is important for optimal resource management. When uncertainty is due to our ignorance of some aspects of the underlying ecology, the isolated equilibrium states characterizing optimal exploitation for many renewable resource problems become equilibrium intervals. Genuinely stochastic events shift the optimal equilibrium states, but maintain the structure of isolated equilibria.
Body size and biomass distributions of carrion visiting beetles: do cities host smaller species?
Authors: Ulrich Werner , Komosiński Karol , Zalewski Marcin
Published: March 2007

The question how animal body size changes along urban–rural gradients has received much attention from carabidologists, who noticed that cities harbour smaller species than natural sites. For Carabidae this pattern is frequently connected with increasing disturbance regimes towards cities, which favour smaller winged species of higher dispersal ability. However, whether changes in body size distributions can be generalised and whether common patterns exist are largely unknown. Here we report on body size distributions of carcass‐visiting beetles along an urban–rural gradient in northern Poland. Based on samplings of 58 necrophages and 43 predatory beetle species, mainly of the families Catopidae, Silphidae, and Staphylinidae, we found contrary patterns of necrophages and predatory beetles. Body sizes of necrophages decreased towards the city centre and those of predators remained unchanged. Small necrophages and large predators dominated in abundance in the city centre. Necrophage body sizes appeared to be more regularly spaced in the city centre than expected from a random null model and in comparison to the rural pattern, pointing to increased competition.
Sex differences in the effectiveness of angiotensin receptor blockers and angiotensin converting enzyme inhibitors in patients with congestive heart failure — A population study
Authors: Hudson Marie , Rahme Elham , Behlouli Hassan , Sheppard Richard , Pilote Louise
Published: March 2007

Background:

Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have been shown to improve survival in patients with congestive heart failure (CHF). We wish to determine whether there are sex‐related differences in the optimal treatment of congestive heart failure.

Methods:

Using administrative databases, all patients > >=65 years of age discharged with a diagnosis of CHF between January 1998 and March 2003 and who filled a prescription for an ARB or an ACE inhibitor within 90 days of discharge were identified. Time to all‐cause death in women and men on ACE inhibitors or ARBs was compared.

Results:

There were 10,223 women (8627 ACE inhibitors and 1596 ARBs) and 9475 men (8484 ACE inhibitors and 991 ARBs). Hypertension was more common in women (50.1%) than men (33.1%). Women on ARBs had better survival than those on ACE inhibitors (adjusted hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.59, 0.80). There was no difference in survival in men prescribed ARBs compared to ACE inhibitors (HR 1.10, 95% CI 0.95, 1.30).

Conclusion

These sex differences in treatment‐related outcome are important but should be confirmed in a randomized trial before ARBs are preferentially prescribed to women with CHF.
Intestinal paracellular permeability is not affected in chronic congestive heart failure
Authors: Schaufelberger M. , Ekman I. , Björnsson E. , Kalaitzakis E. , Ekman T.
Published: March 2007

Background:

In chronic heart failure (CHF) it has been proposed that a dysfunction of the gastrointestinal barrier could lead to translocation of endotoxin into the systemic circulation. A secondary inflammatory reaction, observed as increased levels of cytokines, could negatively affect cardiac function. The aims of this paper were therefore to determine whether patients with CHF have a disturbed mucosal barrier and whether it was possible to detect endotoxin in venous blood.

Methods:

Nineteen stable patients with CHF (New York Heart Association II–III, EF≤40% or EF>40% and earlier hospitalisation for heart failure) were investigated. Twenty healthy subjects (HS group) and 25 patients, who were admitted for bone marrow transplantation (BMT group), served as controls. Gastrointestinal permeability was assessed by a 51Cr‐EDTA absorption test.

Results:

Eleven patients with and eight without peripheral oedema were included. Median age was 76.5 years. Intestinal permeability was 1.82±1.96% in the CHF patients and 1.54±.59% and 1.9±.9% in HS and BMT groups, respectively (p=0.4 and p=0.7, CHF vs HS and BMT, respectively). No difference was found between patients with and without oedema and endotoxins were below the detection limit in all patients.

Discussion:

This study does not support the hypothesis that patients with CHF have a dysfunctional gastrointestinal barrier, at least as assessed by the 51Cr‐EDTA resorbtion test.
Sex differences in formalin‐induced pain in prenatally stressed infant rats
Authors: Butkevich Irina P. , Barr Gordon A. , Vershinina Elena A.
Published: March 2007

The aim of this work was to study the effects of prenatal stress on nociceptive responses in the formalin test in female and male infant (7‐day‐old) Long‐Evans hooded rats. Prenatally stressed infant rats displayed biphasic flinching+ shaking behavior whereas non‐stressed animals showed only a weak second phase. Pain sensitivity in prenatally stressed males was significantly greater than that of prenatally non‐stressed males during the second phase only; there were no differences in pain sensitivity between prenatally stressed and non‐stressed females. Moreover prenatally stressed male rats pups demonstrated that the second phase of the response to formalin was enhanced relative to the second phase in stressed females. The current and previous data [Butkevich IP, Barr GA, Mikhailenko VA, Otellin VA. Increased formalin‐induced pain and expression of fos neurons in the lumbar spinal cord of prenatally stressed infants rats. Neurosci Lett 2006a;403:222–226] show increased tonic pain in prenatally stressed infant rats and a large increase in the number of formalin‐induced fos‐like immunoreactivity in the spinal cord dorsal horn. There is a concomitant decrease in serotonin‐like immunoreactivity in the lumbar spinal cord dorsal horn [Butkevich IP, Barr GA, Otellin VA. Effect of prenatal stress on behavioral and neural indices of formalin‐induced pain in infant rats. Abstracts, 35th Annual Meeting of Soc. For Neurosci. 2005a. Program No. 512.4 Washington, DC: Society for Neuroscience]. Given the decreased level of perinatal testosterone in prenatally stressed rats to which infant males are more sensitive than females, we suggest that these hormonal, behavioral and neuronal indices are strongly interrelated in prenatally stressed 7‐day‐old rat pups and that the decreased surge of testosterone may contribute to the increased behavioral response in the second phase in male rat pups. Mechanisms underlying the behavioral pain response induced by inflammation in prenatally stressed rat pups are characterized by sexual dimorphism even prior to the activational effects of sex hormones.
Intermonomer electron transfer in the bc1 complex dimer is controlled by the energized state and by impaired electron transfer between low and high potential hemes
Authors: Shinkarev Vladimir P. , Wraight Colin A.
Published: March 2007

The cytochrome bc
1 complex (commonly called Complex III) is the central enzyme of respiratory and photosynthetic electron transfer chains. X‐ray structures have revealed the bc
1 complex to be a dimer, and show that the distance between low potential (b
L) and high potential (b
H) hemes, is similar to the distance between low potential hemes in different monomers. This suggests that electron transfer between monomers should occur at the level of the b
L hemes. Here, we show that although the rate constant for b
L
→
b
L electron transfer is substantial, it is slow compared to the forward rate from b
L to b
H, and the intermonomer transfer only occurs after equilibration within the first monomer. The effective rate of intermonomer transfer is about 2‐orders of magnitude slower than the direct intermonomer electron transfer.
Maternal vitamin D depletion alters neurogenesis in the developing rat brain
Authors: Cui Xiaoying , McGrath John J. , Burne Thomas H.J. , Mackay‐Sim Alan , Eyles Darryl W.
Published: March 2007

Evidence is accumulating that normal levels of vitamin D are important for brain development. Vitamin D acts as an anti‐proliferative agent in a wide variety of tissues and developmental vitamin D (DVD) deficiency has been shown to alter brain structure and function. The aim of this study was to investigate the effect of DVD deficiency on neuroprogenitor formation in the neonatal brain. We show that DVD deficiency increased the number of neurospheres formed in cultures from the neonatal subventricular zone. Exogenous vitamin D added to the culture medium reduced neurosphere number in control but not DVD cultures. We show the receptor for vitamin D is concentrated in the subventricular zone and is also present in cultured neurospheres prepared from this region. These results show that vitamin D can regulate cell proliferation in the developing brain. Further studies are warranted to examine the underlying mechanisms for these findings.
Thrombocytosis in cats: A retrospective study of 51 cases (2000–2005)
Authors: Rizzo Francesca , Tappin Simon W , Tasker Séverine
Published: March 2007

Feline haematology profiles of patients presented to the University of Bristol Small Animal Hospital from January 2000 to October 2005 were evaluated for thrombocytosis (defined as a platelets count of >700×109/l and confirmed on smear evaluation). Thrombocytosis was found in 79 cats (4.64% of the hospital feline population), with values ranging from 703 to 1895×109/l. Signalment, clinical presentation, concurrence of other haematological abnormalities, diagnoses and outcome were evaluated in 51 cases in which complete medical records were available. Other variables (feline immunodeficiency virus/feline leukaemia virus status, thyroxine level, haemoplasma PCR, toxoplasma antibody titres) were also evaluated. No association was found between the presence of thrombocytosis and breed or gender. Gastrointestinal signs were the most common clinical presentation. Lymphopenia was the most common concurrent haematological abnormality. Based on final diagnosis reached, cats were grouped both according to the DAMNITV classification and according to the body system affected. Amongst the DAMNITV classification, inflammatory/infectious conditions were most commonly associated with thrombocytosis. According to body systems, gastrointestinal involvement was most represented, followed by endocrine cases. No association was found between the severity of thrombocytosis and outcome.
The ‘elected’ and the ‘excluded’: sociological perspectives on the experience of place and community in old age
Authors: PHILLIPSON CHRIS
Published: March 2007

This article explores various issues concerned with belonging and identity in the context of community change and residential location. It examines the changing nature of community attachments in later life, and their impacts on the quality of old age lives. It also notes the increased importance of environmental perspectives within gerontology, not least because environments are being transformed through the diverse social, cultural and economic changes associated with globalisation. The argument is developed that globalisation offers a new approach to thinking about community and environmental relationships in later life, and that the impact of global change at a local level has become an important dimension of sociological aspects of community change. It is argued that it is especially important to apply these perspectives to older people, given that many have resided in the same locality for long periods. At the same time, globalisation also gives rise to new types of movement in old age, and is constructing an expanding mix of spaces, communities and lifestyle settings. A key argument of the article, however, is that global processes are generating new social divisions, as between those able to choose residential locations consistent with their biographies and life histories, and those who experience rejection or marginalisation from their locality.
Ocean bottom pressure changes lead to a decreasing length‐of‐day in a warming climate
Authors: Landerer Felix W. , Jungclaus Johann H. , Marotzke Jochem
Published: March 2007

We use a coupled climate model to evaluate ocean bottom pressure changes in the IPCC‐A1B climate scenario. Ocean warming in the 21st and 22nd centuries causes secular oceanic bottom pressure anomalies. The essential feature is a net mass transfer onto shallow shelf areas from the deeper ocean areas, which exhibit negative bottom pressure anomalies. We develop a simple mass redistribution model that explains this mechanism. Regionally, however, distinct patterns of bottom pressure anomalies emerge due to spatially inhomogeneous warming and ocean circulation changes. Most prominently, the Arctic Ocean shelves experience an above‐average bottom pressure increase. We find a net transfer of mass from the Southern to the Northern Hemisphere, and a net movement of mass closer towards Earth's axis of rotation. Thus, ocean warming and the ensuing mass redistribution change the length‐of‐day by −0.12 ms within 200 years, demonstrating that the oceans are capable of exciting nontidal length‐of‐day changes on decadal and longer timescales.
Quantification of growth and lateral propagation of the Kashi anticline, southwest Chinese Tian Shan
Authors: Chen Jie , Heermance Richard , Burbank Douglas W. , Scharer Katherine M. , Miao Jijun , Wang Changsheng
Published: March 2007

The Kashi anticline is a north vergent, asymmetric, doubly plunging detachment fold located in the SW Tian Shan foreland. We combine structural, magnetostratigraphic, and topographic data to define the fold's lateral propagation, surface uplift, and concomitant exhumation. Two new magnetostratigraphic sections indicate that the fold began growing at ∼1.4 Ma and by 1.07 Ma, deformation had propagated eastward ∼13 km at an average rate of ∼40 km/Myr. Subsequently, propagation rates increased at least twofold, until the fold reached >60 km in length by 0.8 ± 0.3 Ma. Since then, eastward fold propagation slowed to ∼15 km/Myr, and the eastern 15–25% of the fold remains buried in the rapidly aggrading foreland. The structure and topography of the emergent fold support interpretations of fold growth in three stages: initial symmetric lateral growth both east and west to a total length of ∼30 km followed by, first, rapid and, then, slower eastward lengthening to 72 ± 10 km total length. Shortening rates as high as 1.9−0.2+0.3 mm/yr characterize the western part of the fold but decrease toward the east. Significant dissection of the emergent fold does not occur until topographic relief is sufficient (∼200 m) to permit stripping of protective conglomerates from across the fold's upper surface. As differential rock uplift continues following breaching of the conglomerate, ∼75% of the rock raised above local base level is subsequently eroded at rates as high as 2.4 km/Myr. Despite extensive erosion, the modern fold topography mimics spatial patterns of both long‐term shortening and variations in rock uplift.
A finite volume numerical approach for coastal ocean circulation studies: Comparisons with finite difference models
Authors: Chen Changsheng , Huang Haosheng , Beardsley Robert C. , Liu Hedong , Xu Qichun , Cowles Geoffrey
Published: March 2007

An unstructured grid, finite volume, three‐dimensional (3‐D) primitive equation coastal ocean model (FVCOM) has been developed for the study of coastal ocean and estuarine circulation by Chen et al. (2003a). The finite volume method used in this model combines the advantage of finite element methods for geometric flexibility and finite difference methods for simple discrete computation. Currents, temperature, and salinity are computed using an integral form of the equations, which provides a better representation of the conservative laws for mass, momentum, and heat. Detailed comparisons are presented here of FVCOM simulations with analytical solutions and numerical simulations made with two popular finite difference models (the Princeton Ocean Model and Estuarine and Coastal Ocean Model (ECOM‐si)) for the following idealized cases: wind‐induced long‐surface gravity waves in a circular lake, tidal resonance in rectangular and sector channels, freshwater discharge onto the continental shelf with curved and straight coastlines, and the thermal bottom boundary layer over the slope with steep bottom topography. With a better fit to the curvature of the coastline using unstructured nonoverlapping triangle grid cells, FVCOM provides improved numerical accuracy and correctly captures the physics of tide‐, wind‐, and buoyancy‐induced waves and flows in the coastal ocean. This model is suitable for applications to estuaries, continental shelves, and regional basins that feature complex coastlines and bathymetry.
Role of tides in Arctic ocean/ice climate
Authors: Holloway Greg , Proshutinsky Andrey
Published: March 2007

A three‐dimensional coupled ocean/ice model, intended for long‐term Arctic climate studies, is extended to include tidal effects. From saved output of an Arctic tides model, we introduce parameterizations for (1) enhanced ocean mixing associated with tides and (2) the role of tides fracturing and mobilizing sea ice. Results show tides enhancing loss of heat from Atlantic waters. The impact of tides on sea ice is more subtle as thinning due to enhanced ocean heat flux competes with net ice growth during rapid openings and closings of tidal leads. Present model results are compared with an ensemble of nine models under the Arctic Ocean Model Intercomparison Project (AOMIP). Among results from AOMIP is a tendency for models to accumulate excessive Arctic Ocean heat throughout the intercomparison period 1950 to 2000 which is contrary to observations. Tidally induced ventilation of ocean heat reduces this discrepancy.
Oceanic latent heat fluxes: Consistency with the atmospheric hydrological and energy cycles and general circulation modeling
Authors: Edwards J. M.
Published: March 2007

Traditional climatological estimates of oceanic latent heat fluxes are significantly lower than those obtained from general circulation models (GCMs). A recent satellite‐based climatology yields higher latent heat fluxes, which are in closer agreement with those implied by measurements of ocean heat transports. This motivates a review of the consistency of the atmospheric energy and hydrological cycles as represented by current climatologies. Depending on the combination of climatologies selected, mean imbalances of up to ±13 W m−2 are found in the hydrological cycle over the oceans. The energy cycle shows a lack of net atmospheric absorption for all combinations of climatologies, except those involving constrained surface radiative fluxes: With unconstrained climatologies the global annual mean imbalance in the energy cycle lies in the range −13 to −38 W m−2. A seasonal analysis of the energy cycle shows significant regional imbalances in the winter hemisphere and suggests that it would be premature to focus on the surface shortwave radiation alone to explain imbalances in this cycle. The simulation of the latent heat fluxes in the Met Office's GCM is compared with climatological data, considering the exchange coefficient, the wind speed and the specific humidity. A revision to the exchange coefficient for moisture reduces it to values in closer agreement with recent field observations. Small decreases in the oceanic latent heat fluxes result, reducing the discrepancy with the climatologies, while the atmosphere is cooled and dried.
Grain orientation, texture, and internal stress optically evaluated by micro-Raman spectroscopy
Authors: Becker M. , Scheel H. , Christiansen S. , Strunk H. P.
Published: March 2007

We present a method to experimentally determine the components of stress tensors within grains of multicrystalline materials by micro-Raman spectroscopy. This method is applied to multicrystalline silicon wafers as they are produced for solar cells. Currently, μ-Raman spectroscopy is intensively used to measure stresses in silicon wafers, structures, and devices of known crystallographic orientations. For these cases, the determination of stresses from Raman peak shifts is straightforward. In multicrystalline silicon, however, arbitrary grain orientations complicate the determination of stress tensor components, which depend on the crystallographic orientations of the particular grains. The Raman intensities depend on the polarization direction of the incident and scattered laser light and again on the crystallographic grain orientations. This intensity dependence is used to determine the crystallographic grain orientations. Once the orientation is determined, the components of the stress tensor (with respect to a fixed reference coordinate system—the sample stage), can be calculated numerically from the Raman peak shifts. As examples, we determine (i) the stress components of a nearly plane stress state around the tip of a microcrack and (ii) the stress components at a grain boundary in a multicrystalline silicon wafer.
Enhanced Raman scattering by self-assembled silica spherical microparticles
Authors: Yi K. J. , Wang H. , Lu Y. F. , Yang Z. Y.
Published: March 2007

A technique was developed to achieve enhanced Raman scattering of the silicon photon modes using closely packed micro- and submicron silica spherical particles. Investigation on the particle-size dependence of Raman enhancement revealed that the strongest enhancement occurs when the particle diameter is equal to the spot size of the incident laser beam. Calculations using the OPTIWAVE™ software based on the finite difference time domain algorithm under the perfectly matched layer boundary conditions were carried out. The results showed that photonic nanojets are formed in the vicinity outside the particles along the propagation direction of incident light. It was found that the nanojets are confined to a length of 100nm with a waist of 120nm. The presence of the strongly localized electromagnetic fields within the nanojets accounts for the enhanced Raman scattering. This technique has potential applications both in modern and traditional areas of surface science such as surface oxidation, adhesion, corrosion, and catalytic processes, and many other areas in biology, chemistry, materials science, and microelectronics.
High in-plane anisotropy of epitaxial CoPt(110) alloy films prepared by cosputtering or molecular beam epitaxy on MgO
Authors: Abes M. , Ersen O. , Meny C. , Schmerber G. , Acosta M. , Arabski J. , Ulhaq-Bouillet C. , Dinia A. , Panissod P. , Pierron-Bohnes V.
Published: March 2007

We present structural and magnetic properties of three sets of structures: as-deposited CoPt films cosputtered at 900 K on MgO(110) substrates with a Pt(110) buffer layer and CoPt films deposited by molecular beam epitaxy directly on MgO(110) substrates at 900 K, as prepared and annealed at 900 K. All layers have the L10 tetragonal structure. The chemical long-range ordering for the as-deposited CoPt films is incomplete in contrast with the annealed CoPt films, where long-range order is the highest. The structural study of these CoPt films grown on MgO(110) has pointed out that three variants of the L10 phase coexist. The proportion of x and y variants, with the concentration modulation along a vector oriented at 45° with respect to the growth direction, is higher than the proportion of the z variant with the concentration modulation within the plane. The magnetic study shows an in-plane easy magnetization axis with a large magnetic anisotropy. This is interesting for the magnetic recording media with classical longitudinal writing and reading heads. The simulation of the magnetization loops confirms that the easy magnetization axis is within the plane and along the [11¯0] direction, favored by the dominant x and y variants.
Structural and electrical characterization of CeAlO3 ceramics
Authors: Feteira Antonio , Sinclair Derek C. , Lanagan Michael T.
Published: March 2007

The crystal structure and electrical properties of CeAlO3 ceramics prepared by the mixed oxide route have been investigated. X-ray and electron diffraction data show the room temperature structure to be described by the tetragonal I4∕mcm space group [a=5.3253(5)Å and c=7.5860(9)Å; Z=4, and theoretical density, Dx=6.64g∕cm3]. CeAlO3 ceramics sintered at 1500°C under flowing 5%H2–95%N2 gas for 4h reach ∼94% of Dx with a microstructure of randomly distributed equiaxed grains of average grain size ∼2μm. Conventional transmission electron microscopy reveals needle-shaped ferroelastic domains in some grains. The relative permittivity εr of CeAlO3 ceramics is ∼18–20 in the range of ∼10–300K. At room temperature and microwave frequencies, CeAlO3 ceramics exhibit εr∼20.7, Qfr∼40117GHz (at 9.5GHz), and τf∼−57ppm∕K. The ion polarizability for Ce3+ is calculated to be 4.46Å3. Revised dielectric polarizabilities for rare-earth lanthanides are also presented.
Short-circuit photocurrent in epitaxial lead zirconate-titanate thin films
Authors: Pintilie L. , Vrejoiu I. , Le Rhun G. , Alexe M.
Published: March 2007

Photovoltaic properties of the metal-ferroelectric-metal structures, having SrRuO3 metal oxide electrodes and Pb(Zr,Ti)O3 (PZT) as ferroelectric layer, are investigated by the short-circuit photocurrent (SC-PHC) in the 200–800nm wavelength domain. The band-gap dependence on the Zr content was determined from the spectral distribution of the SC-PHC signal. It was found that the band-gap value increases linearly with the Zr content, from about 3.9eV to about 4.4eV. It is shown that the sign and the magnitude of the signal depend on the internal bias and on the spontaneous polarization direction and value. The photocurrent describes a hysteresis loop similar to that of the ferroelectric polarization and can be used as a nondestructive readout of the nonvolatile memories based on PZT films. The existence of a significant SC-PHC signal at wavelengths corresponding to subgap energies is attributed to the presence of charged, deep levels in the forbidden band. It is also shown that the epitaxial PZT films have the potential for solid-state UV detectors, with current responsivity as high as 1mA∕W. The results are not entirely consistent with a bulk photovoltaic effect and are discussed in the frame of a Schottky barrier model for the metal-ferroelectric interface.
Temperature dependence of the complete material coefficients matrix of soft and hard doped piezoelectric lead zirconate titanate ceramics
Authors: Georges Sabat Ribal , Mukherjee Binu K. , Ren Wei , Yang Guomao
Published: March 2007

We have used resonance methods to determine the variation of all the independent piezoelectric, elastic, and dielectric material coefficients, as well as the corresponding electromechanical coupling factors, of soft and hard doped piezoelectric lead zirconate titanate (PZT) ceramics with compositions near the morphotropic phase boundary, as a function of temperature ranging between −165 and 195°C. The material coefficients were obtained by analyzing the fundamental resonance of the impedance or admittance spectra as a function of frequency for several sample resonance geometries. The piezoelectric coefficients d33, −d31, and d15, as well as the dielectric permittivity coefficients ε11T and ε33T, generally increased with temperature for both soft and hard PZT samples. However, the elastic compliance coefficients s11E, −s12E, s33E, and s55E exhibited abnormal variations seen as broad peaks over parts of the tested temperature range. Additionally, thermal hystereses were observed in all the studied material coefficients over the temperature cycle. Finally, it was noted that, overall, the material coefficients of soft PZT varied significantly more than those of hard PZT under changing temperature conditions.
Theoretical and computational modeling of self-oscillating polymer gels
Authors: Yashin Victor V. , Balazs Anna C.
Published: March 2007

The authors model wave propagation in swollen, chemoresponsive polymer gels that are undergoing the oscillatory Belousov-Zhabotinsky (BZ) reaction. To carry out this study, they first modify the Oregonator model for BZ reactions in simple solutions to include the effect of the polymer on the reaction kinetics. They then describe the gel dynamics through the framework of the two-fluid model. The polymer-solvent interactions that are introduced through the BZ reaction are captured through a coupling term, which is added to the Flory-Huggins model for polymer-solvent mixtures. The resulting theoretical model is then used to develop the gel lattice spring model (gLSM), which is a computationally efficient approach for simulating large-scale, two-dimensional (2D) deformations and chemical reactions within a swollen polymer network. The 2D calculations allow the authors to probe not only volume changes but also changes in the sample’s shape. Using the gLSM, they determine the pattern formation and shape changes in 2D rectangular BZ gels that are anchored to a solid wall. They demonstrate that the dynamic patterns depend on whether the gel is expanded or contracted near the wall, and on the sample’s dimensions. Finally, they isolate a scenario where the detachment of the gel from the wall leads to macroscopic motion of the entire sample.
Characteristics of micronozzle gas flows
Authors: Xie Chong
Published: March 2007

The fluid characteristics of gas flows in the micronozzle whose throat height is 20μm were investigated by the direct simulation Monte Carlo (DSMC) method. In a series of cases, the dependence of mass flux on the pressure difference was gained, and the DSMC’s results show good agreement with the experimental data. The comparison of mass flux and the Mach number contours between the DSMC and Navier-Stokes equations adding slip boundary also reveals quantitatively that the continuum model will be invalid gradually even when the average Knudsen number is smaller than 0.01. As one focus of the present paper, the phenomenon of the multiple expansion-compression waves that comes from the nozzle’s divergent part was analyzed in detailed.