bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of anisotropic scattering of radiation in laminar forced convection in a parallel‐plate duct
Authors: Tsai J. R. , Özisik M. N.
Published: March 2009

Effects of anisotropic scattering to heat transfer in hydrodynamically‐developed, thermally‐developing steady laminar forced flow of a gray fluid between two infinite parallel plates are investigated for the case when the inlet temperature of the fluid is less than the wall temperature. An implicit finite difference scheme is applied to solve the energy equation, while the high order PN method is used to solve the radiation part of this problem. The effects of the anisotropy, the conduction‐to‐radiation parameter, the optical thickness, the reflectivity of the plates and the inlet temperature on the local Nusselt number are studied.
The effect of charged additives and heat pretreatment on the dewatering of fuel‐grade peat
Authors: Cooper D.G. , Eccles E.R.A. , Sheppard J.D.
Published: March 2009

The addition of salt, mineral acid or polyelectrolyte or the preheating of fuel‐grade peat results in significant improvement of the amount of water released during mechanical pressing.

The charged species all act by suppressing the charge on the colloidal particles and, for different reasons, organic salts, protons and polyelectrolytes are all more effective than simple inorganic salts. The cations with large organic portions, including surfactants, have an augmented adsorption to the particle surface because of the hydrophobic effect. The polyelectrolytes are strongly associated with the particles because of the chelate effect. Protons are very effective because they can actually neutralize the net charge on the particle surface by forming covalent bonds with the acid functions.

The mechanism by which heat pretreatment improves dewatering is not caused by suppression of the surface charge. The effect could be due to melting or softening of peat waxes causing alterations of surface features which improve water release. It is also possible that heating provides sufficient energy to overcome the energy barrier keeping the particles apart.
De‐t‐butylation of t‐butylphenols over dealuminated zeolites in liquid‐solid system
Authors: Takahashi Takeshige , Kai Takami , Tashiro Masashi
Published: March 2009

Liquid‐solid phase de‐t‐butylation of p‐t‐butylphenols was carried out over original and dealuminated zeolites to determine the effect of catalyst pore size and acidity on the reaction rate and catalyst fouling rate. The de‐t‐butylation rate over the original zeolites was mainly dependent upon their micro pore sizes. Although the dealumination by acid leaching decreased strong acid sites, the de‐t‐butylation rate over dealuminated HY zeolite was higher than that on the original zeolite. The present dealumination is a useful method to prepare an acid catalyst for de‐t‐butylation in a liquid‐solid system.
Models and methods of simulating gas pipeline blowdown
Authors: Botros K. K. , Jungowski W. M. , Weiss M. H.
Published: March 2009

Estimation of gas pipeline blowdown time requires the determination of the pressure‐time history for the unsteady discharge of gas through a blowdown stack open to the atmosphere. Computational procedures entail various assumptions whose validity and contributions to the accuracy are often not assessed. This paper discusses the computational models and solution methods and further assesses the significance of the various assumptions involved.

Volume and pipe models, numerical and analytical methods of solution, effects of stack entrance and friction losses and discharge coefficient are evaluated. The accuracy of a particular model or method of solution is greatly dependent on the fL/D ratio of the pipe section under blowdown. Comparison with field measurements of a straight pipe section and a complicated compressor station yard piping enabled evaluation of the above models.
Steady state hydrodynamics and mass transfer characteristics of a karr extraction column
Authors: Camurdan M. C. , Baird M. H. I. , Taylor P. A.
Published: March 2009

The steady state hydrodynamics of the holdup in a 15 cm column agree quite well with mechanistic predictions at conditions approaching flooding. In the presence of mass transfer (acetic acid from the dispersed kerosene phase to the continuous water phase), the holdup data below flooding are not well predicted by the model due to enhanced droplet coalescence. The prediction of holdup at flooding is a function of the ratio of the flow rates but is independent of the physicochemical properties of the extraction system, and therefore can be used to estimate the flooding holdup regardless of the occurrence of mass transfer. In the second part of the paper, steady state mass transfer characteristics of the column were also simulated using a mechanistic model. Despite the difficulty of estimating parameters such as the mass transfer coefficient, the model curves could be arbitrarily adjusted to fit observed exit concentrations. These steady state results provide useful insights on the non‐linearity of the system from a control viewpoint.
Factors affecting cake resistance in non‐Newtonian filtration
Authors: Kozicki W.
Published: March 2009

A methodology for evaluation of surface effects including polymer adsorption‐gel formation or slip within the pores of a filter cake has been developed and applied to constant pressure filtration of calcium carbonate in aqueous hydroxyethyl cellulose (Natrosol 250G, Hercules Powder Company) slurries. The fundamental framework of non‐Newtonian filtration is generalized to include the Blake, Kozeny‐Ergun and Kozeny‐Carman cake models and the cake resistances γK and αR, in conjunction with the correction terms JRN and Jgen, within a unified framework. Relationships are developed between the latter quantities and the effect of the bed model on the evaluations of the filtration characteristics is delineated.

Significant polymer adsorption‐gel formation was found to take place in the constant pressure filtration of calcium carbonate in aqueous Natrosol 250G slurries. The resultant cake porosities were larger and the effective cake porosities lower than comparable porosities for cakes deposited from water slurries.

The wide variation of JRN with the characteristic index N is attributed to the small size of the slurry particles. Polymer adsorption is shown to extend, and slip on the particle surface to reduce the variation of JRN with N.
Natural convection in liquid encapsulated czochralski growth of gallium arsenide
Authors: Sabhapathy P. , Salcudean M. E.
Published: March 2009

The natural convection in the melt during LEC growth of GaAs is studied numerically for a crucible radius of 0.1 m, melt heights 0.025 m and 0.05 m, and crystal radii 0.025 m and 0.05 m. When only the crucible side wall is heated, the flow is unicellular moving up the side wall, along the melt‐encapsulant interface, downward beneath the crystal, and along the bottom toward the side wall. With heating at the top of the crucible, the side wall temperature can be lowered without freezing the melt near the melt‐encapsulant interface. The flow is often multi‐cellular when the bottom of the crucible is heated. An optimum heating at the top and bottom of the crucible can flatten the isotherms near the crystal‐melt interface and improve the diameter control.
Adsorptive separation of Kr from N2‐Part II. Development of a pilot unit
Authors: Tezel F. H. , Ruthven D. M. , Boniface H. A. , Sridhar T. S.
Published: March 2009

Design and development of a pilot scale chromatographic process for separation of trace amounts of krypton from a nitrogen atmosphere is described. The system uses a large column (1.20 m × 0.055 m i.d.) packed with H‐mordenite adsorbent and operated under overload conditions. A preliminary economic evaluation suggests that this process is competitive with the conventional cryogenic distillation process.
Sparged loop reactors
Authors: Joshi J. B. , Ranade V. V. , Gharat S. D. , Lele S. S.
Published: March 2009

Circulating bubble columns or loop reactors form one of the important classes of modified bubble columns. The present paper analyses the performance of external loop air lift reactors (EL‐ALR). The EL‐ALR has many advantageous features especially at large scale. These arise from its feature of having controlled liquid circulation which is the key parameter for the design and operation of EL‐ALR contactors. Therefore, a reliable and generalised circulation model has been presented. The reliability of the model depends on the accuracy of the predictive methods for the gas hold‐up and the two‐phase fractional pressure drop. Detailed analysis of these fundamental parameters of gas‐liquid flows has been presented. The effects of design (area ratio of riser to downcomer, height to diameter ratio and volume of reactor) and operating (gas flow rates and sparging locations) parameters on the performance of the EL‐ALR have been analysed in detail. A rational basis has been developed for the estimation of pressure drop, mixing time and mass transfer coefficient. An optimum combination of design and operating parameters has been suggested and a criterion has been developed for the optimum location of spargers. An attempt has been made to provide critical analysis of the published information and to construct a coherent picture of EL‐ALR.
Generic model control — A case study revisited
Authors: Harris T. J. , Mclellan P. J.
Published: March 2009

The application of the Generic Model Control (GMC) algorithm to the control of an evaporator has been reported recently by Lee et al. (1989). The results of their case study are claimed to demonstrate the superiority of the nonlinear GMC algorithm over conventional techniques including Dynamic Matrix Control. In this note it is shown that for the evaporator example the improved performance arises primarily from the full multivariable and feedforward nature of the control law, rather than from the nonlinear nature of GMC.
Impingement heat transfer under a confined slot jet. Part I: Effect of surface throughflow
Authors: Polat S. , Mujumdar A. S. , Douglas W. J. M.
Published: March 2009

Local and average heat transfer coefficients were measured for a confined turbulent slot jet impinging on a permeable surface at which there may be throughflow. Local Nusselt number was obtained using a unique porous sensor designed for measurement of local heat transfer at a permeable surface which is subjected to rapidly and widely varying heat transfer. Measurements were performed for a wide range of jet Reynolds number and throughflow rates. Convective heat transfer coefficients was found to be enhanced by throughflow, and the enhancement factor in terms of Stanton number to be independent of jet Reynolds number and of extent of heat transfer area.
Interaction between micro‐ and macro‐mixing during reactions in agitated tanks
Authors: Thoma S. , Ranade V. V. , Bourne J. R.
Published: March 2009

The present investigation focusses on the interactions between micro‐and macro‐mixing in a stirred tank reactor, operated in the semi‐batch mode. With long feed times only micromixing controls reaction, but below a critical feed time macroscopic gradients also become important. Experiments generated a coherent data set which can be used as a design guide and also for model validation. A competitive, consecutive azocoupling reaction was carried out, whereby imperfect mixing produces finite values of XS (yield of secondary product) which can be conveniently used as a mixing index. The influences of feed location, feed rate, stirrer speed, concentrations and vessel size on selectivity were studied. The micromixing model of Baldyga and Bourne (1989) was extended to include interactions between macro‐and micro‐mixing and should be valid for feed times below the critical value, although not so short as the macromixing time in the vessel. Model predictions were compared with the experimental results.
Forced convection subcooled boiling of binary mixtures
Authors: Sivagnanam P. , Balakrishnan A. R. , Varma Y. B. G.
Published: March 2009

A mode based on an additive mechanism of heat transfer is proposed for forced convection subcooled boiling of binary mixtures. The contributing modes of heat transfer are: (i) the heat transferred as latent heat by the rising bubbles, (ii) the heat transferred as the heat contained in the superheated thermal layer that is removed from the surface in the wake of the rising bubbles and (iii) the single phase forced convection heat transfer from the heating surface not influenced by the bubbles. Experimental data from the literature on binary systems show good agreement with the model, validating the postulated mechanism.
Convection naturelle transitoire dans les liquides à viscosité variable
Authors: Maslouhi A. , Robillard L.
Published: March 2009

On étudie le rǒle de la viscosité dépendant linéairement de la température sur la convection laminaire le long d'une plaque verticale soumise à un flux de chaleur constant. L'analyse est basée sur la résolution numérique des équations de couche limite instationnaire utilisant une procédure implicite de différences finies. On présente les profils de vitesse de température et du nombre de Nusselt à l'état permanent et dans la période transitoire. En régime transitoire, les champs de vitesse et de température atteignent une valeur maximale avant de décroǐtre légèrement jusqà leurs valeurs permanentes. Ce phénomène appelé “overshoot”, peut ětre amplifié ou atténué selon les valeurs que l'on donne au paramètre sans dimension caractérisant la variation de la viscosité.
Carbon monoxide hydrogenation over cobalt catalyst in a tube‐wall reactor: Part II. Modelling studies
Authors: Dalai A. K. , Esmai M. N. , Bakhshi N. N.
Published: March 2009

A mathematical model was developed to predict the performance of Fischer‐Tropsch Synthesis over cobalt catalyst in a tube‐wall reactor. Comparison was made between model predictions and previous experimental results (part 1 of this paper) for pressures 0.35‐1.03 MPa, temperatures 250−275°C, and exposure velocities 139‐722 μ/s. The agreement was good. The model predicts an increase in methanation activity with temperature. Carbon monoxide and hydrogen conversions, and water and carbon dioxide concentrations increase along the reactor axis. With an increase in exposure velocity, hydrocarbons and carbon dioxide production increase, but water production decreases. However, the water‐gas shift activity increases continuously along the reactor axis. The model is based on two‐dimensional transport equations, and employs the orthogonal collocation method in its numerical predictions.
Production of annatto concentrates in spouted beds
Authors: Massarani G. , Passos M. L. , Barreto D. W.
Published: March 2009

Annatto is composed of a natural reddish‐yellow pigment, which is commonly used in the food, cosmetic and pharmaceutical industries. This pigment is easily extracted from Bixa orellana seeds by particle impact and attrition rather than by solvent extraction. Seeds must be dried at a safe temperature to preserve the pigment quality. Experiments show that the annatto powder produced in a non‐conventional spouted bed has a high pigment content and is thus suitable for commercial use. A comparative analysis of the bixin extraction in different systems demonstrates that this spouted bed unit can be competitive for commercial applications. Hydrodynamic and drying parameters were studied to improve the powder production rate in this unit.
Influence of geometry on gas holdups in a reversed flow jet loop reactor
Authors: Padmavathi G. , Remananda Rao K.
Published: March 2009

The effects of ratio of draft tube to reactor diameter (Dd/D), liquid nozzle diameter (dN), aeration tube diameter (dG) and immersion height of the two‐fluid nozzle into the draft tube (HN) on overall and annulus gas holdups for the air‐water system were evaluated experimentally in a reversed flow jet loop reactor over wide ranges of gas and liquid flow rates. Both the gas holdups increased with increasing gas and liquid flow rates and with decreasing dN and HN. The influence of dG on gas holdups is found to vary with gas flow rates. Correlations are proposed to predict gas holdups.
Solid‐liquid equilibria in the ternary system nacl‐kcl‐h2o
Authors: Farelo F. , Von Brachel G. , Offermann H.
Published: March 2009

Binary and ternary solubility data were measured for the NaCl‐KCl‐H2O system in the temperature range 293‐360 K using a standard visual method. The solid‐liquid phase diagram of the ternary system was calculated from the binary data and from the activity coefficients of the electrolytes evaluated by the Pitzer model. Some empirical functions of temperature were used to describe the virial coefficients. The calculated ternary solubilities were compared with the experimental values yielding a very good agreement. Therefore, it was possible to conclude that, in the range of concentration and temperature studied, the Pitzer model provides an excellent representation of the activity coefficients, thus allowing the accurate prediction of solubilities in the ternary system.
Hydrogen evolution in alkaline solution on electrolytic nickel‐cobalt and nickel‐iron deposited with different bath compositions and current densities
Authors: Fan Chonglun , Piron D. L. , Meilleur M. , Marin L.‐P.
Published: March 2009

Nickel‐cobalt and nickel‐iron electrodeposits were characterized as hydrogen electrodes in alkaline water electrolysis (6 mol/L KOH, 25°C). The nickel‐based codeposits were fabricated with different bath compositions and at different current densities. The hydrogen evolution in water electrolysis on the nickel‐based codeposits was apparently enhanced as compared with that on nickel. The improvement of the electrocatalytic behaviour of the hydrogen electrodes is attributed to their composition and an increase of their active surface, which are dependent on the electrodeposition conditions.
Computer‐aided Measurement of Vapor‐Liquid Equilibrium in a Still
Authors: Hiaki Toshihiko , Yamato Kazutaka , Miyazawa Hajime , Kojlma Kazuo
Published: March 2009

Isothermal vapor‐liquid equilibria were measured using a still with the aid of a computer for control of the temperature and measurement of the total pressure. The measurements were made with circulation of both the vapor and liquid phases in a still of the Rogalski and Malanowski type (1980). The isobaric vapor‐liquid equilibria were measured for the benzene + 2‐propanol system at 101.3 kPa in order to test the consistency of results obtained with this still. Isothermal vapor‐liquid equilibria were measured for the 2,3‐dimethylbutane + methanol system at 313.15 K. The experimental data were correlated with the Wilson (1964) equation.
Co‐Extraction — Selective stripping for the recovery of nickel and copper from the leach liquor of ocean nodules
Authors: Pandey B. D. , Bagchi D. , Kumar Vinay
Published: March 2009

Ferromanganese deep sea nodules of the Indian Ocean have recently been recognised as a potential source of metals like copper, nickel, cobalt and manganese. For the treatment of the sea nodules following the reduction roast‐ammonia leach process, the leach liquor containing copper, nickel and cobalt was processed to separate and recover these metals by solvent extraction (SX) using 25% LIX 64N in kerosene. Almost quantitative extraction of copper and nickel was realized in a continuous run. During nickel stripping, the small amount of copper in the nickel solution was removed by incorporating a copper extraction step using 10% LIX 64N in kerosene. The purified pregnant nickel electrolyte was electrowon in a non‐diaphragm cell. Copper was similarly recovered by electrowinning (EW). A closed circuit of SX‐EW was run to produce cathodes of nickel and copper with energy consumptions of 3.85 and 2.01 kWh/kg for the respective metals.
The maximum spoutable bed heights of fine particles spouted with air
Authors: Çeçen Ayşe
Published: March 2009

The maximum spoutable bed heights of systems of fine glass spheres spouted with air are studied in flat based semi circular columns of 80 and 152.4 mm diameters using particles with average diameters ranging from 0.3 to 1.3 mm.

New correlations are proposed to predict the maximum spoutable bed heights of air spouted fine particle systems. It is concluded that the influence of the column diameter on the maximum spoutable bed height is significantly decreased compared to coarse particle systems and that it further varies with particle size within the fine particle spouting regime. Data reported in the literature agree with the proposed correlations.
Mass transfer enhancement of acetic acid across a plane kerosene/water interface by an electric field
Authors: Glitzenstein A. , Tamir A. , Oren Y.
Published: March 2009

The intensification of mass transfer of acetic acid from kerosene into water across a plane interface by the application of an electric field normal to the interface is investigated.

The application of an electric field affects mainly mass transport through the bulk of the organic phase rather than the interface. In the range (5–30) × 104 V/m the mass transfer coefficient changes from 8 × 10−6 to 2 × 10−5 m/s. A model based on the movement of electric charges in the organic phase indicates that a Sherwood‐Grashof correlation for free convection only is also suitable for the electrically driven process if the Grashof number is modified to take into account the effect of the electric field on the movement of the electric charges.
Cinétique de la calcination du coke de pétrole en atmosphères neutre et oxydante
Authors: Dubuisson C. , Charette A. , Kocaefe D.
Published: March 2009

Une étude cinétique de la dévolatilisation d'échantillons représentatifs de coke de pétrole est menée sous des conditions proches de celles existant dans les fours industriels de calcination. On analyse les effets de la nature du milieu (neutre ou oxydant), du taux de chauffage et du pourcentage d'oxygène en milieu oxydant. Les expériences sont réalisées dans un four à induction et mettent en oeuvre des analyses thermogravimétriques et chromatographiques. Les résultats montrent que, sous certaines conditions, la nature du milieu influence le processus de dévolatilisation. En atmosphère oxydante, un taux de chauffage faible et un contenu faible en matières volatiles favorisent une attaque du coke par l'oxygène. Les comportements réactionnels sont établis en suivant les concentrations de CH4, H2, CO et CO2. Dans les régions où le coke n'est pas attaqué, un modèle cinétique permet de comparer les paramètres (ordre de réaction, énergie d'activation et facteur pré‐exponentiel) caractérisant le phénomène de dévolatilisation dans les deux milieux (neutre et oxydant). On constate que le milieu oxydant favorise une augmentation de l'énergie d'activation.
Déformation subie par une nappe de mercure soumise à l'impact d'un jet liquide bidimensionnel immergé
Authors: Bensmaili A. , Coeuret F.
Published: March 2009

Le travail étudie la déformation subie par une nappe de mercure recevant perpendiculairement un jet liquide immergé bidimensionnel de faible épaisseur. On a fait varier la largeur du jet, le nombre de Reynolds d'injection et la hauteur du jet. On a mesuré expérimentalement la profondeur et le diamètre de la cavité faite par le jet dans la nappe de mercure et on a comparé les valeurs obtenues à des expressions théoriques de la littérature. En dépit de l'échelle relativement réduite, le comportement du système étudié est décrit convenablement par des modèles proposés pour des sytèmes à grande échelle.
The origin and population dynamics of annually re-occurring Paratanytarsus grimmii (Diptera: Chironomidae) colonising granular activated carbon (GAC) adsorbers used in potable water treatment
Authors: Olsen A. , Leadbeater B.S.C. , Callow M.E. , Holden J.B. , Bale J.S.
Published: March 2009

Various sampling techniques were employed to study the population dynamics and identify the origin of annually re-occurring infestations of Paratanytarsus grimmii in granular activated carbon (GAC) adsorbers. Larvae overwintered in all adsorbers studied and are the main source of endemic persistent infestations. Significant differences in larval densities were identified between the down-flow cell (mean of 61 larvae per 0.3 l of GAC) and the up-flow cell (mean of 14 larvae per 0.3 l of GAC) of each adsorber. Larvae were distributed uniformly with no significant difference in density at any depth through the 2-m carbon column. Application of anaerobic treatment as a control measure was ineffective at low temperatures due to a slow down in chironomid metabolism. During summer months, ovipositing females have access to all locations within the GAC adsorber building by flight, leading to immediate re-colonisation of anaerobically-treated adsorbers. Regeneration of GAC in individual cells served only to reduce larval numbers but not remove them completely, particularly when only one of the two cells is regenerated at any one time.
Host races of the pea aphidAcyrthosiphon pisumdiffer in male wing phenotypes
Authors: Frantz A. , Plantegenest M. , Simon J.-C.
Published: March 2009

The evolution of reproductive isolation without geographic isolation (sympatric speciation) has recently gained strong theoretical and empirical supports. It is now widely admitted that many host-specific phytophagous insect species have arisen through shifting and adapting to new plants. The pea aphidAcyrthosiphon pisumhas received considerable attention in this context and is now considered as a probable case of incipient sympatric speciation through host specialization. In Europe, three host races have been described so far, one on annual plants (pea and broad bean) and two on perennial plants (red clover and alfalfa, respectively). These host races are genetically differentiated and exhibit strong ecological specialization affecting their preferences and performances on alternative plants. Here, we investigate whether other life-history traits of ecological importance are associated with host specialization in the species. In particular, becauseA. pisumshows a genetically determined male wing variation, we tested if its host races also differ in their proportion of winged/wingless male phenotypes. We used a large collection of pea aphid lineages sampled on pea, broad bean, red clover and alfalfa and analyzed their male production by placing them in conditions inducing the sexual phase inA. pisum. Striking differences in the frequency of male dispersal genotypes were found between host populations; aphids producing winged males were in high proportion among lineages from annual hosts, while those producing wingless males were in high proportion on perennial ones. The evolutionary maintenance and ecological consequences of this association between habitat specialization and male wing variation are discussed.
Determinants of fruit and vegetable intake in England: a re-examination based on quantile regression
Authors: Boukouvalas Georgios , Shankar Bhavani , Bruce Traill W
Published: March 2009

Objective

To examine the sociodemographic determinants of fruit and vegetable (F&V) consumption in England and determine the differential effects of socio-economic variables at various parts of the intake distribution, with a special focus on severely inadequate intakes.

Design

Quantile regression, expressing F&V intake as a function of sociodemographic variables, is employed. Here, quantile regression flexibly allows variables such as ethnicity to exert effects on F&V intake that vary depending on existing levels of intake.

Setting

The 2003 Health Survey of England.

Subjects

Data were from 11 044 adult individuals.

Results

The influence of particular sociodemographic variables is found to vary significantly across the intake distribution. We conclude that women consume more F&V than men; Asians and blacks more than whites; co-habiting individuals more than single-living ones. Increased incomes and education also boost intake. However, the key general finding of the present study is that the influence of most variables is relatively weak in the area of greatest concern, i.e. among those with the most inadequate intakes in any reference group.

Conclusions

Our findings emphasise the importance of allowing the effects of socio-economic drivers to vary across the intake distribution. The main finding, that variables which exert significant influence on F&V intake at other parts of the conditional distribution have a relatively weak influence at the lower tail, is cause for concern. It implies that in any defined group, those consuming the least F&V are hard to influence using campaigns or policy levers.
Involvement of nitric oxide in ultraviolet B-induced activation of phenylalanine ammoniumlyase and stimulation of flavonoid biosynthesis in Ginkgo biloba leaves
Authors: Hao Gangping , Du Xihua , Shi Renjiu , Wang Jianmei , Feng Lei
Published: March 2009

Previous studies have shown that ultraviolet B (UV-B) irradiation can stimulate biosynthesis of secondary metabolites. Several other studies have demonstrated that nitric oxide (NO) is an important signal molecule that plays a key role in plant defence responses to UV-B irradiation. However, the signalling mechanism of NO involvement in UV-B-induced secondary-metabolite synthesis is unclear. The purpose of the present study is to investigate the role of NO in the accumulation UV-B-induced secondary metabolite in the leaves of Ginkgo biloba. Our results showed that UV-B irradiation induced multiple biological responses in the leaves of G. biloba, including increases in both NO production and nitric oxide synthase (NOS) activity, and subsequent activation of phenylalanine ammoniumlyase (PAL) and synthesis of flavonoids. Application of NO via the donor sodium nitroprusside (SNP) enhanced UV-B-induced PAL activity and increased accumulation of flavonoids in G. biloba leaves. Both the NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) and the NO scavenger 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (c-PTIO) reduced the production of NO. Moreover, UV-B-induced increase in PAL activity and flavonoid accumulation were suppressed by L-NAME and c-PTIO. These findings suggest a causal relationship between NO release and both PAL activity and flavonoid accumulation under UV-B irradiation. In addition, the results also indicate that NO, produced via NOS-like activity in ginkgo leaves subjected to UV-B irradiation, might act as an essential signal molecule for triggering the activation of PAL and synthesis of flavonoids.
Phylogenetic relationships among southern South American species of Camptosema, Galactia and Collaea (Diocleinae: Papilionoideae: Leguminosae) on the basis of molecular and morphological data
Authors: Sede Silvana M. , Tosto Daniela , Talia Paola , Luckow Melissa , Poggio Lidia , Fortunato Renée
Published: March 2009

The neotropical genus Camptosema in its southern distribution is represented by the following four species: Ca. paraguariense, Ca. praeandinum, Ca. rubicundum and Ca. scarlatinum. Ca. rubicundum is the only species with all the diagnostic characters of the genus, i.e. tubular calyx. The other three taxa are related morphologically and cytologically to Galactia and Collaea, two closely allied genera in the subtribe Diocleinae. Individual and combined phylogenetic analyses of morphology, ITS and trnL-F were conducted to examine the position of these species as well as to explore their relationship with Galactia and Collaea species in southern South America. In none of the analyses does Camptosema species form a monophyletic group. Instead, they are scattered in different groups. These results together with cytological, morphological and AFLP data provide good support for re-evaluating the taxonomic position of these species within Camptosema.
Pollinators of Eucalyptus regnans (Myrtaceae), the world's tallest flowering plant species
Authors: Griffin A. Rod , Hingston Andrew B. , Ohmart Clifford P.
Published: March 2009

Insect visitors to the flowers of Eucalyptus regnans F.Muell. in a remnant natural stand were classified into 33 functional pollinator groups according to taxonomic affinity and body size. In total, 92% of insects caught were dipterans; however, most of these were small and did not contribute significantly to pollination. For the majority of taxa, which have short mouthparts and therefore need to intrude themselves into the flower while feeding on nectar, there was a highly significant relationship between body length and the number of E. regnans pollen grains carried on the body. Mean pollen loads ranged from 20 grains per insect for sepsid flies to 84 000 for large tachinid flies. An index of pollen-deposition potential, which is based on population size and pollen load, suggested that the larger tachinid, calliphorid and syrphid flies were the most important pollen vectors and that larger sphecid wasps also played a significant role. Many taxa appeared to contribute little to pollination because they were uncommon and/or did not carry large quantities of pollen. A convention is proposed whereby groups are weighted according to their contribution to total pollen-deposition potential. For E. regnans, a ratio of 5 Diptera/1 Hymenoptera + (Coleoptera/Lepidoptera) is described, with the taxa in parentheses contributing less than 10% of the total.
A catch-all leguminous tree: Erythrina velutina visited and pollinated by vertebrates at an oceanic island
Authors: Sazima Ivan , Sazima Cristina , Sazima Marlies
Published: March 2009

Species of the pantropical genus Erythrina (Fabaceae) are visited by perching and/or hovering birds in the mainland. At the oceanic island of Fernando de Noronha, north-eastern Brazil, we found that Erythrina velutina Willd. blooms during the dry season and the flowers are visited by a small vertebrate assemblage. Flowers last 2 days and their stigmas remain receptive, although only first-day flowers produce nectar. Nectar is dilute and produced copiously. All terrestrial native vertebrates (three of them endemics), the dove Zenaida auriculata noronha, the perching birds Vireo gracilirostris and Elaenia ridleyana, and the lizard Euprepis atlanticus are regular visitors and pollinators. The features of E. velutina conform to those of passerine-pollinated species within the genus. Its nectar is a resource sought by the vertebrates, which visit the inflorescences from dawn to sunset. Since none of the visitors depends on nectar as a major food source, the flowers are likely to serve a dual purpose, i.e. water balance and energy intake, similarly to the findings for some Erythrina species in Neotropic and Palaeotropic mainlands. However, E. velutina is the only species within the genus that is visited and pollinated by doves and lizards.
The role of selective angiographic embolization of the musculo‐skeletal system in haemophilia
Authors: RODRIGUEZ‐MERCHAN E. C. , JIMENEZ‐YUSTE V.
Published: March 2009

Summary.  The incidence of haemarthrosis as a result of a spontaneous periarticular aneurysm in haemophilia is very low. In these circumstances, angiographic embolization might be considered as a promising therapeutic and coagulation factor saving option in joint bleeds not responding to replacement of coagulation factor to normal levels. Moreover, embolization should be considered as a possible treatment for postoperative pseudoaneurysms complicating total knee arthroplasty in haemophilia. However, the pathological process of aneurysmal bleeding and clotting factor replacement is entirely different. While embolization is the treatment of choice for some periarticular complications that may occur, it is by no means a panacea for all resistant periarticular bleeds in haemophilia or for postoperative bleeding which usually settles with clotting factor replacement. Another use of arterial embolization is for the treatment of haemophilic tumours of the pelvis, because they can act as a focus for infection and cause cutaneous fistulas. When they present perforations and infections of endogenous origin, their course is usually fatal. Suitable treatment has been investigated on numerous occasions, most of the literature agreeing that the only curative treatment is surgical resection. However, surgical resection after performing arterial embolization to reduce the vascularization of the pseudotumour is a good alternative, thereby reducing the size of the pseudotumour and the risk of bleeding complications during surgery. It is important to bear in mind that despite its efficacy, arterial embolization is an invasive procedure with a reported rate of complications up to 25% (16% minor, 7% serious, 2% death).
Home treatment with bypassing products in inhibitor patients: a 7.5‐year experience
Authors: HOLME P. A. , GLOMSTEIN A. , GRØNHAUG S. , TJØNNFJORD G. E.
Published: March 2009

Summary. The advantages of early treatment of bleeds include minimizing the damage caused by the haemorrhage as well as offering increased convenience and time saved for the patient. The objectives of this prospective, single‐centre study were to evaluate the efficacy, safety and feasibility of long‐term home treatment with bypassing product in inhibitor patients. Since May 2000, 10 haemophilia A patients with high‐titre inhibitors have been included in the study. Nine patients were treated with activated prothrombin complex concentrate (aPCC; factor eight inhibitor bypassing activity, FEIBA™; Baxter AG, Vienna, Austria) and one patient with both aPCC and recombinant activated factor VII (rFVIIa; NovoSeven®; NovoNordisk A/S, Bagsvaerd, Denmark). A total of 1008 infusions of aPCC and 17 infusions of rFVIIa were given in a home treatment setting. The numbers include 448 infusions of aPCC and 10 infusions of rFVIIa given as prophylactic treatment. During the 7.5 years of follow‐up, the patients experienced 431 bleeds. Five hundred and sixty infusions of aPCC and seven infusions of rFVIIa were given to treat these bleeds. Haemostasis was rated as effective in 88% (372/424) and partially effective in 10% (43/424) of the bleeds after a mean number of 1.3 injections. The number of treatments rated as effective was comparable for muscle (90%), joint (85%) and mucocutaneous (86%) bleeds. The safety of the treatment was very good. Only two mild adverse events were reported in total. No thrombotic adverse event has been observed. In conclusion, home treatment with bypassing agents in inhibitor patients is feasible, effective and safe in a long‐term perspective.
Effects of rhubarb on migration of rat hepatic stellate cells
Authors: Lin Yun‐Lian , Wu Ching‐Fen , Huang Yi‐Tsau
Published: March 2009

Background and Aims:  In chronic liver injury, hepatic stellate cells (HSCs) acquire an activated phenotype, migrate to the injured region in response to chemotactic factors, and produce extracellular matrix proteins including collagen. In this study, we investigated the effects of rhubarb (Rheum palmatum L.) on transforming growth factor (TGF)‐β1‐induced expressions of α‐smooth‐muscle actin (SMA) and collagen, and the migration of HSCs.

Methods:  HSC‐T6, a cell line of rat HSCs, was used in the in vitro experiments. An enzyme‐linked immunosorbent assay and Sircol red assay were used to detect the expressions of α‐SMA and collagen, respectively. HSC‐T6 migration was assayed with a transwell apparatus. Phosphorylations of Smad2/3 and mitogen‐activated protein kinases (MAPKs), including extracellular signal‐regulated kinase (ERK) 1/2, p38, and c‐jun N‐terminal kinase (JNK), were analyzed with Western blotting. Matrix metalloproteinase (MMP)‐2 activity was examined by gelatin zymography.

Results:  The results revealed that a rhubarb extract concentration‐dependently attenuated TGF‐β1‐induced α‐SMA and collagen expressions and migration of HSCs. The inhibitory effect of rhubarb was associated with (i) down‐regulation of the phosphorylation of Smad2/3 and JNK, and (ii) attenuation of MMP‐2 activity. Within the working concentrations used, the rhubarb extract did not affect cell viability of HSCs.

Conclusion:  The results suggest that rhubarb attenuated TGF‐β1‐mediated migration of HSCs possibly by interfering with Smad2/3 phosphorylation, the MAPK pathway, and MMP‐2 activity.
Admissions of all gestations to a regional neonatal unit versus controls: 2‐year outcome
Authors: Darlow Brian A , Horwood L John , Wynn‐Williams M Beth , Mogridge Nina , Austin Nicola C
Published: March 2009

Aims:  To assess neurodevelopmental outcome at 2 years for neonatal intensive care unit (NICU) admissions compared with controls, and to trial a parent‐reporting scheme.

Methods:  All infants admitted to the NICU at Christchurch Women's Hospital over a 12‐month period and whose parents were domiciled in a defined geographical region were eligible for study, together with every eighth term infant not admitted (to a total of 300). Parents completed a two‐page questionnaire on their child's 2nd birthday. All infants <28 weeks gestation and a random 300 NICU admissions and 108 controls underwent a paediatric examination and Bayley II assessment at 2 years of age.

Results:  A total of 387 NICU infants (86% eligible) and 306 controls were enrolled. At 2 years of age, 276 NICU infants (89% survivors) and 94 controls (87%) had some follow up. For infants of <33 weeks, 33–36 weeks, ≥37 weeks gestation and controls, the percentage >1 SD below the mean on the Bayley Mental Development Index scales were 33.3, 36.5, 44.6 and 24.1, respectively (P= 0.03); on the Psychomotor Developmental Index scales were 30.0, 29.1, 41.1 and 19.5 (P= 0.02) and the percentage with any cerebral palsy were 11.1, 2.8, 5.2 and 1.2.

Conclusions:  At 2 years of age, NICU graduates have more developmental problems than controls across a range of measures. In many cases, term NICU graduates have the least favourable outcome. There was only moderate agreement between parents' reporting of moderate or severe developmental disability by means of a questionnaire, compared with professionals (kappa statistic 0.38), with parents tending to underestimate problems.
ENDOGENOUS BUSINESS CYCLES: THE INFLUENCE OF CHARACTER TRAITS*
Authors: TAKATA FUJIO
Published: March 2009

This article deals with how business cycles can occur, in light of character traits which influence individual behaviour in an economy. We assume an overlapping generations model in which every consumer has identical instantaneous utility which is additively separable with respect to time. The parameters of utility here include character traits which influence the choice between consumption and savings. In this situation, young individuals choose between current consumption and current savings which lead to future consumption in their old age. Individual character traits, which appear both in the shape of utility functions and in evaluations about utility in the future, affect these choices. And since these choices determine savings, individual character traits can eventually determine how our economy moves. Focusing on the relationship between individual character traits and savings formation, we demonstrate that endogenous business cycles with two periods can occur, in an economy comprised of individuals who opt for current consumption and who are careless in relation to future events, like Aesopian grasshoppers, and in other cases they do not.
ENVIRONMENTAL HEALTH AND CHOICE OF RESIDENCE
Authors: LEVY AMNON
Published: March 2009

This paper analyses the relationships between the values and dispersion of residential properties and the environmental‐health quality of their locations. It constructs residents’ health‐adjusted lifetime‐utility function by combining satisfaction from consumption over the lifespan with risk to life from living in an environmentally unhealthy location. It employs this utility function to analyse willingness to pay for environmental‐health quality, choice of location and residential dispersion and its relationship with income distribution.
Impact of implant support for mandibular dentures on satisfaction, oral and general health‐related quality of life: a meta‐analysis of randomized‐controlled trials
Authors: Emami Elham , Heydecke Guido , Rompré Pierre H. , De Grandmont Pierre , Feine Jocelyne S.
Published: March 2009

Objectives: The aim of this study was to examine systematically the data published on the efficacy of mandibular implant‐retained overdentures from the patient's perspective.

Material and methods: Medline, Embase, The Cochrane Central Register of Controlled Trials and The Cochrane Systematic Reviews Database were searched and complemented by hand searching. All randomized‐controlled trials published in English or French up to April 2007 were included, in which conventional dentures and mandibular implant overdentures in adult edentulous individuals were compared. The outcomes of interest were patient satisfaction, oral and general health‐related quality of life. Random effects models were used to pool the effect sizes (ES) of all included studies.

Results: Ten publications of seven randomized‐controlled trials were identified and eight were included in the meta‐analysis. When compared with mandibular conventional dentures, implant overdentures were rated to be more satisfactory at a clinically relevant level [pooled ES 0.80, z=3.56, 95% confidence intervals (CI) 0.36–1.24, P=0.0004], but a statistical heterogeneity was found (χ2=31.63, df=5, P<0.00001, I2=84%). The pooled ES for oral health quality of life was −0.41 (z=1.31, 95% CI, −1.02 to 0.20; P=0.19, χ2=11.53, df=2, P<0.003, I2=83%). There was a lack of evidence to show the impact of mandibular implant overdenture on perceived general health.

Conclusions: Our findings suggest that, although mandibular implant‐retained overdentures may be more satisfying for edentulous patients than new conventional dentures, the magnitude of the effect is still uncertain. There is a need for additional evidence including cost‐effectiveness analyses on the impact of mandibular implant overdentures and conventional dentures.
Comparative study of four retentive anchor systems for implant supported overdentures – retention force changes
Authors: Bayer Stefan , Steinheuser Daniela , Grüner Manfred , Keilig Ludger , Enkling Norbert , Stark Helmut , Mues Sebastian
Published: March 2009

Objectives:  Wear of attachments leads to a loss of retention and potentially reduces the function of complete dentures. This study evaluated the retention force changes of different prefabricated attachment systems for implant‐supported overdentures to estimate the wear constancy and applicability in clinical practice.

Methods:  Four prefabricated attachment systems were tested [Group SG: retentive ball attachment (Straumann, Switzerland) with gold matrix, Group ST: retentive ball attachment (Straumann, Switzerland) with titanium spring matrix, Group IB: UNOR i‐Ball with Ecco matrix (UNOR, Switzerland) and Group IMZ: IMZ®‐TwinPlus ball attachment with gold matrix (DENTSPLY Friadent, Germany)]. Ten samples of each system were subjected to 10 000 insertion‐separation cycles.

Results:  Results showed that all types of attachments showed wear, which led to a loss of retention force after an initial increase at the beginning of the wear simulation. Attachments with a plastic retention insert or gold matrices underwent the smallest changes in retention force. The titanium spring system showed the largest changes in retention force and a greater variation between the different cycles and specimen. This behaviour is probably caused by a large fitting tolerance of the titanium spring.

Conclusions:  Attachment systems which possess a male and female component of different material composition are preferable. They show smaller changes in the retention force. For retention force increase and wear compensation, an attachment system should be adjustable.
Metastatic mast cell tumour in a dog presenting with spinal pain
Authors: Cooper MA , Bennett PF , Laverty PH
Published: March 2009

The clinical, advanced imaging and surgical features of a case of canine extradural mast cell tumour are presented. This rare location has only been reported once before as a primary lesion, although the present case may be a metastatic lesion. Given the frequent occurrence and treatment of cutaneous mast cell tumours in dogs, the finding of spinal metastasis is an important reminder to consider metastatic neoplasia in cases of previously treated cancers presenting with spinal pain.