bluuebunny/crossref_metadata_2025 huggingface dataset:
Ageing across the life span: time to think again
Authors: Piérard G E
Published: November 2004

Living organisms are subject to ageing. This natural process has gained greater importance in socially and medically affluent societies. For many, ageing connotes unattractive changes in the appearance of the skin. The gross morphological changes of ageing skin are mirrored by a range of more profound age‐associated physiological declines. Thus, skin ageing can be put into other perspectives which lie at the interfaces of molecular biology, cellular biology, oncology and cosmetic dermatology. Genetically programmed replicative senescence and stress‐induced premature senescence (SIPS) are two processes that are fundamental to skin ageing. Some iteroparous species can be used as animal models for human ageing.

 Undoubtedly, scientific understanding of skin ageing is firmly rooted in the distinction between intrinsic and extrinsic types of ageing. However, seven major types of skin ageing can be distinguished: genetic, chronological, solar, behavioural, endocrinological, catabolic and gravitational types. Preventative measures can target each of these.
The cosmetic treatment of wrinkles
Authors: Rona C , Vailati F , Berardesca E
Published: November 2004

Wrinkles now have a greater social impact because people live longer. Science and hedonism overlap in the search for causes, treatments and prevention of wrinkles.

The cosmetic approach to wrinkles includes:

Cleansing

Photoprotection

Active ingredients

Active ingredients go well beyond simple moisturisers and exert a more complex activity in protecting skin from external injuries, nourishing it and removing its superficial layers. Transport systems and excipients are increasingly effective. Functional agents currently include alpha hydroxy acids (AHAs), poly‐AHAs, complex poly‐AHAs, retinoids, fish polysaccharides, anti‐enzymatic agents, antioxidants (including ascorbic acid, pycnogenol, ursolic acid, vegetable isoflavones, vitamin E, coenzyme Q10, lipoic acid, resveratorol, l‐carnosine and taurine) as well as agaricic acid and various plant extracts. All are reviewed in this text. Most are topical, some can be given by mouth, even as food supplements.

Cosmetics are becoming closer to drugs in preventing and treating wrinkles. Included amongst the cosmeceuticals are the anti‐wrinkle agents described herein.
Management of complications after implantation of fillers
Authors: De Boulle Koenraad
Published: November 2004

Soft tissue augmentation is widely practised by a variety of different practitioners.

A new classification of filler substances and procedures, taking into account long‐term safety and reversibility of side effects, is proposed:

non‐permanent and biodegradable,

semi‐permanent and biodegradable,

permanent and reversible,

permanent and non‐reversible.

Complications and adverse effects occur with all fillers and all filler procedures. Insufficient experience is an important contributory factor. Underreporting is probably common. Commonest are haematomas, ecchymoses, infections, papulopustular or acneiform lesions, non‐hypersensitivity related swelling and oedema, erythema, changes in pigmentation, palpability of the implant and necrosis of overlying tissue. Specific therapeutic approaches for these complications and practical recommendations to minimize or avoid them are discussed.

Hypersensitivity reactions and granuloma formation are the most distressing adverse effects. They can occur with most fillers. Mostly these hypersensitivity reactions are local granulomas but, rarely, generalized reactions also occur. Case reports of systemic reactions after injection of hyaluronic acid are documented. Treatments include steroids, minocycline and immunomodulatory agents, such as cyclosporin, tacrolimus and ascomycin. In selected cases, surgical procedures are necessary to elimirate granulomatous reactions. Implant migration and facial lipoatrophy are encountered with certain compounds. Extreme caution is therefore advocated before using permanent and non‐reversible products for soft tissue augmentation.

Those who use fillers need to be familiar with the complications of fillers and with the treatment of those complications.
Evaluation of the perceived impact of an interdisciplinary healthcare ethics course on clinical practice
Authors: Carpenter Christine , Ericksen Janet , Purves Barbara , Hill David S.
Published: November 2004

Healthcare professionals and educators perceive that interdisciplinary education initiatives facilitate improved interdisciplinary team functioning and practice in a diversity of healthcare settings, but evidence to support this perception has been lacking. This report presents data from a descriptive study conducted in two phases – a focus group and the development and administration of a questionnaire – that sought to evaluate healthcare professionals’ perception of the impact of having taken an interdisciplinary course in healthcare ethics on the subsequent clinical practice of healthcare professionals, and to identify implications for future ethics‐related, interdisciplinary course development. The course organization and the course participants and faculty are briefly described. The findings indicate that respondents judged the course to be valuable in enhancing their ability to engage in the interdisciplinary aspects of practice and in addressing ethical issues. They identified effective components of the education experience and areas in which the course organization could be improved. Based on these findings, implications for future curriculum and course planning and evaluation research are discussed.
Managing the UK Grey Partridge Perdix perdix recovery: population change, reproduction, habitat and shooting
Authors: AEBISCHER NICHOLAS J. , EWALD JULIE A.
Published: November 2004

In 1995, the UK Government designated the Grey Partridge Perdix perdix as a priority species under its Biodiversity Action Plan (BAP). The Game Conservancy Trust (GCT), nominated as lead partner for the species, launched a programme to help Grey Partridge recovery by (1) raising awareness among the shooting and farming communities, (2) encouraging land managers and local BAP groups to conserve Partridges by setting numerical targets and offering feedback from counts on how to increase numbers, and (3) motivating by example by setting up a site demonstrating management techniques and the increase in Partridge abundance that ensues. Building on past research, we quantify the amount of habitat management required to achieve the BAP targets of halting the decline and achieving population recovery. Using three major GCT databases, (1) the National Gamebag Census, which collates data on shooting bags and gamebird releasing in the UK, (2) the Partridge Count Scheme, which monitors national Partridge density and reproduction, and (3) the Sussex Study, which monitors local Partridge population dynamics over 37 years, we emphasize the importance of good breeding success for increasing densities, review the evidence that management can be successful and evaluate the impact of shooting on Grey Partridge conservation.
The breeding ecology of Reed Buntings Emberiza schoeniclus in farmland and wetland habitats in lowland England
Authors: BRICKLE NICK W. , PEACH WILL J.
Published: November 2004

We studied the nesting and feeding ecology of Reed Buntings Emberiza schoeniclus breeding on farmland and wetland habitats along the Trent Valley in Nottinghamshire, England. Rank and emergent vegetation accounted for most nests and most foraging by provisioning adults. Caterpillars and spiders accounted for 70% of chick invertebrate prey and all broods were fed cereal grain or other vegetable matter. Variation in the abundance of key invertebrate prey across habitats accounted for the foraging preferences of adult buntings. Depredation was the main cause of nest failure, and survival of nests at the egg stage was positively related to the extent of nest concealment. A measure of total brood biomass was positively related to the abundance of key invertebrate prey within 100 m of nests. Rank and emergent vegetation provided Reed Buntings with greater nest concealment and a richer source of invertebrate prey than agricultural habitats such as set‐aside, cereals and oilseed rape. The provision of rank and emergent vegetation on farmland is likely to increase the nesting opportunities and productivity of Reed Buntings in agricultural landscapes.
Testing solutions in grass‐dominated landscapes: a review of current research
Authors: BUCKINGHAM DAVID L. , ATKINSON PHIL W. , ROOK ANDREW J.
Published: November 2004

In this paper we review the experimental development of agri‐environment measures for use on grasslands. Sward structure has been shown to have a strong influence on birds’ ability to forage in grasslands, but the effects of food abundance on foraging behaviour are poorly understood and this hinders development of grassland conservation measures. The experiments described have a dual purpose: to investigate the foraging ecology of birds on grasslands and to test candidate management measures. Most of the work featured focuses on increasing invertebrate food resources during the summer by increasing habitat heterogeneity. We also identify important gaps in the habitats provided by existing or experimental measures, where similar dual‐purpose experiments are required.
Non‐inversion tillage and farmland birds: a review with special reference to the UK and Europe
Authors: CUNNINGHAM HEIDI M. , CHANEY KEITH , BRADBURY RICHARD B. , WILCOX ANDREW
Published: November 2004

This paper reviews the current knowledge of the effects of non‐inversion tillage (NIT) on farmland birds and their food resources. NIT is a method of establishing a crop without using a mouldboard plough and is becoming increasingly popular in the UK. NIT generally disturbs the soil to shallower depths than conventional tillage and is therefore expected to have beneficial effects on biodiversity on arable land as compared with mouldboard ploughing. The diets of farmland birds change throughout the year, and many species take invertebrates over the breeding season. Seeds are also important for many species of farmland birds throughout the year and especially over the winter months. The effects of NIT on these farmland bird food resources, in particular ground beetles (Coleoptera: Carabidae), spiders (Arachnida: Araneae), earthworms (Annelida) and seeds (arable weeds and cereal crops) are reviewed.
The relevance of non‐farmland habitats, uncropped areas and habitat diversity to the conservation of farmland birds
Authors: FULLER R. J. , HINSLEY S. A. , SWETNAM R. D.
Published: November 2004

Use of non‐farmland habitats by species generally perceived as ‘farmland birds’ is common, yet these habitats are not always considered in conservation strategies aimed at population recovery. At the national scale, many farmland species occur in landscapes not dominated by farmland. An analysis of distribution atlas data coupled with remotely sensed habitat data showed that for 16 out of 28 farmland species, less than half of the breeding range was associated with high cover of lowland farmland. However, with a few exceptions, populations breeding in non‐farmland habitats are likely to depend on farmland at some time in the year. Within farmland landscapes, uncropped areas and patches of non‐farmland habitat can provide nesting, foraging or roosting resources. Habitats that are scarce on farmland and that provide potential supplementary or complementary resources to those available within the productive areas of farmland include ruderal vegetation, rough grassland and scrub. Enhancing habitat diversity through provision of modest quantities of these habitats will benefit farmland birds. Complete knowledge of year‐round habitat requirements and patterns of resource use at all scales is needed if robust national conservation plans are to be developed for farmland species. Similarly, interactions between the farmland and non‐farmland sections of populations need to be determined.
Swards and structure: the interactions between farming practices and bird food resources in lowland grasslands
Authors: MCCRACKEN D. I. , TALLOWIN J. R.
Published: November 2004

The ideal grassland to encourage plants and invertebrates suitable as food for farmland birds contains a mixture of grasses and broad‐leaved plants with a range of vegetation heights and structures. However, as a result of agricultural intensification the majority of lowland grasslands in the UK now lack botanical and structural complexity. Plants within intensively managed swards are allowed little capacity to set seed, and the majority of invertebrates within these grasslands are either too small to be utilized by birds or inaccessible because of dense vegetation or impenetrable soils. Further research is required into the impact of different grassland management practices on the abundance and accessibility of bird food resources at both the field and the landscape level. The major challenge will be to identify changes to grassland management practices that provide significant biodiversity benefits and yet allow productive livestock farming systems to continue.
Sustainable Arable Farming For an Improved Environment (SAFFIE): managing winter wheat sward structure for Skylarks Alauda arvensis
Authors: MORRIS ANTONY J. , HOLLAND JOHN M. , SMITH BARBARA , JONES NAOMI E.
Published: November 2004

Research has shown a close correlation between the decline of the UK Skylark Alauda arvensis population and the replacement of spring‐sown cereals with winter‐sown varieties, in which advanced sward development prevents successful multiple nesting attempts and reduces access for foraging. Widescale reversal of sowing times is unlikely for commercial reasons, so research has recently focused on ways of manipulating the sward structure of winter wheat to prolong access to nest‐sites and food. An RSPB pilot study investigated leaving small ‘undrilled patches’ in otherwise conventionally managed winter wheat crops. This option was later incorporated into a fully replicated experimental design, as part of the Sustainable Arable Farming For an Improved Environment (SAFFIE) project. This large consortium‐led project aims to test solutions for improving biodiversity within winter‐cereal‐dominated rotations. The experiment described here ran over 2002–3, with three field‐scale ‘treatments’ on 15 sites in the first year. The treatments compare (1) conventional winter wheat, (2) winter wheat sown in double‐normal width (25 cm) wide‐spaced rows (WSR) and (3) winter wheat with two 4‐m by 4‐m undrilled patches per hectare (UP). Results from the 2002 breeding season showed that undrilled patch treatments supported more breeding Skylarks for longer, most likely by aiding accessibility of food. WSR rows were little used by Skylarks and did not improve the abundance of favoured seed and invertebrate food items over conventional crops. Nesting performance and foraging patterns are discussed with reference to invertebrate food abundance and its accessibility, as determined by sward structure.
Demographic and environmental causes of the decline of rural Song Thrushes Turdus philomelos in lowland Britain
Authors: PEACH WILL J. , ROBINSON ROB A. , MURRAY KATHRYN A.
Published: November 2004

We review current knowledge of demographic mechanisms and environmental factors implicated in the population decline of Song Thrushes Turdus philomelos in rural Britain since the mid‐1970s, and present new analyses of regional variation in population changes. Increased mortality during the first year of life (from fledging to recruitment) is highlighted as a potential demographic mechanism having driven the population decline, while Song Thrushes in a rapidly declining farmland population were making too few nesting attempts to sustain local numbers. Breeding Song Thrushes are strongly associated with non‐cropped habitats such as woodland edge, field boundaries, gardens and scrub; they make substantial use of grassland, but avoid cereals when foraging. Earthworms constitute a key component of Song Thrush diet and the availability of this prey is strongly influenced by moisture levels in surface soils. Several lines of evidence suggest that dry surface soils during summer are deleterious to the productivity and survival of Song Thrushes, and regional variation in the rates of population change in Britain during 1970–86 was negatively correlated with the extent of under‐field drainage on farmland (the main function of which is to promote the drying of surface soils). Increasing dryness of agricultural soils and the loss of grassland from eastern arable counties have probably both contributed to the declines of rural Song Thrushes in Britain. Loss of hedgerows and scrub, and the degradation of woodland may also have contributed to population declines but the role of predators remains unclear. Recovery of rural Song Thrush populations requires challenging new policy initiatives that should aim to restore nesting cover (scrub and woodland understorey), grazed grassland in arable‐dominated areas and damper soils in summer.
Bullfinch Pyrrhula pyrrhula breeding ecology in lowland farmland and woodland: comparisons across time and habitat
Authors: PROFFITT FIONA M. , NEWTON IAN , WILSON JEREMY D. , SIRIWARDENA GAVIN M.
Published: November 2004

Bullfinch Pyrrhula pyrrhula populations decreased by 33% in Britain over the years 1977–82, the period of steepest decline. The timing of this decline and its greater severity on farmland (−65%) than in woodland (−28%) point to agricultural intensification as a likely environmental cause, but previous analyses of survival rate and breeding success data have not been able to identify a clear demographic mechanism. As part of an investigation into the causes of the decline of Bullfinch populations, we conducted an intensive study of breeding phenology and success in farmland and woodland habitats of Oxfordshire and neighbouring counties in 1999–2001, using a combination of nest monitoring and autumn mist‐netting. Breeding success data were supplemented with nest record and mist‐net capture data collected in the same geographical area during the 1960s and 1990s to compare pre‐ and post‐decline productivity. We found a change in the distribution of first‐egg dates, with median first‐egg dates 17–18 days later in the 1990s. This reflected a change in the centre of gravity of the breeding season rather than the timing of its start and end, with proportionally fewer birds laying in May and early June, and proportionally more between then and the end of July. We found no significant difference in any aspect of productivity per breeding attempt between the two periods, although there was a trend towards higher egg period failure rates in the 1990s. October age ratios indicated higher annual productivity in the 1990s. We found no significant differences between farmland and woodland in Bullfinch breeding success or timing of breeding. The cause of the decline of Bullfinch populations in both woodland and farmland, and the greater severity of the decline in farmland, seems more likely to be found in: (a) the impacts of habitat deterioration on breeding densities, (b) constraints on survival probability outside the breeding season and/or (c) the impacts of increasing populations of Sparrowhawks Accipiter nisus on the ability of Bullfinches to exploit resources in some habitats. Further investigation of the breeding ecology and phenology of Bullfinches would best be focused on understanding the causes and possible demographic consequences of the shift in first‐egg date distribution in favour of later‐summer nesting attempts.
Effects of habitat on the use of supplementary food by farmland birds in winter
Authors: SIRIWARDENA GAVIN M. , STEVENS DANAË K.
Published: November 2004

Providing supplementary food for seed‐eating birds in winter is likely to be a key strategy, in some form, in future efforts to conserve farmland biodiversity. We present interim analyses of data on the bird use of artificial feeding sites under the RSPB‐led BirdAid project and the BTO‐led Winter Food for Birds (WFFB) project, investigating the influence of the habitat context at the local and landscape scales on the use of supplementary food by Yellowhammer Emberiza citrinella, Corn Bunting Miliaria calandra, Tree Sparrow Passer montanus, House Sparrow Passer domesticus, Chaffinch, Fringilla coelebs, Greenfinch Carduelis chloris, Goldfinch C. carduelis and Reed Bunting Emberiza schoeniclus. Our results reveal species‐specificity, rather than general patterns, in relationships between habitat variables and counts. The responses of the only species for which both BirdAid and WFFB provided data, the Yellowhammer, differed between the projects, suggesting that the results were not geographically general. The results fail to indicate justifiable firm habitat prescriptions for site locations that would suit a number of species. Clearer patterns were apparent in results with respect to areas of major habitats in the landscapes surrounding feeding sites, which suggested that local abundance could have an important effect on the use of supplementary food. Future analyses of data from these projects will attempt to separate the competing probable habitat influences on local bird abundance and alternative resource availability.
A blueprint for the countryside
Authors: SUTHERLAND WILLIAM J.
Published: November 2004

Much of the UK (and some of Western Europe) consists of ancient farmland and thus conservation effort is concentrated on maintaining intermediate levels of intervention. Conservation therefore differs markedly from that in much of the rest of the world. The future of farmland birds depends upon the success of agri‐environment schemes and the changes in agriculture resulting from the development of new technologies. The experience of agri‐environment schemes shows that they have patchy success. An alternative approach is to align conservation with the other external benefits to society of natural and semi‐natural landscapes, such as health, flood protection, water purification and tourism and then restore natural ecosystems. Many of the biodiversity objectives are then produced while achieving other objectives and reducing expenditure. Within this framework it may also be possible, based on use of Vera's interpretation of landscape history, to create a few areas of natural ecosystem functioning. The expected future changes in EU agricultural support could provide the opportunity to achieve this.
ARCHAEOMETRIC ANALYSES ON ‘CORINTHIAN B’ TRANSPORT AMPHORAE FOUND AT GELA (SICILY, ITALY)*
Authors: BARONE G. , CRUPI V. , GALLI S. , LONGO F. , MAJOLINO D. , MAZZOLENI P. , SPAGNOLO G.
Published: November 2004

The aim of this work is to throw light on the archaic production of ‘Corinthian B’ amphorae, which are widely diffused in the Western Mediterranean basin and are also present in Greece, but whose geographical provenance is still under discussion.

We analysed a group of 37 samples belonging to different ceramic classes dated to the sixth and fifth centuries bc. In particular, there were 19 sherds of trade amphorae of the so‐called archaic ‘Corinthian B’ type, from archaeological excavations in Gela (Sicily, Italy). As a comparison, we also investigated 18 samples of tiles and local coarse pottery from Sibari (Calabria, Italy).

The samples were analysed using different techniques, such as optical analysis with a polarized‐light microscope (OM), X‐ray diffraction (XRD), Fourier transform–infrared absorption (FT–IR) and inductively coupled plasma–optical emission spectroscopy (ICP–OES). The combination of these complementary analytical methods allowed us to characterize the samples, determine their firing temperatures and identify the probable provenance.

The study of thin sections of sherds by OM allowed us to divide the investigated amphorae into two main groups: the first was characterized by a composition that suggested a Western provenance, in particular from the Calabrian–Peloritan region; the second one was very similar to the ‘Corinthian B’ amphorae that come from Corinth and have been classified as ‘fabric class 1’ by

Whitbread (1995

).

The XRD and FT–IR results permitted us to determine the mineral composition of the findings and to estimate their firing temperature. The ICP–OES technique was particularly useful in identifying the production centres. In fact, in the studied pottery, this analysis revealed Ni and Cr values that were noticeably different between Greek and southern Italian production.
NEUTRON ACTIVATION ANALYSIS OF COLONIAL CERAMICS FROM SOUTHERN HIGHLAND ECUADOR*
Authors: JAMIESON R. W. , HANCOCK R. G. V.
Published: November 2004

Sixty‐one ceramic samples collected in Cuenca, Ecuador, were analysed by neutron activation analysis in an attempt to establish their elemental compositions. The bulk of the samples were manufactured in the region of Cuenca, with others imported from Quito in the northern highlands of Ecuador, from Panama Vieja in Panama, and from Seville in Spain. Relative to the Cuenca ceramics, the Spanish samples were separable primarily by their high Ca contents; the Panamanian ceramics by their high Cs contents; and the Quito ceramics by their high Na contents. The ceramics made within the region surrounding Cuenca are much more difficult to separate, with Ba and other elements being potentially important.
Local Heat Transfer and Pressure Drop for Finned-Tube Heat Exchangers Using Oval Tubes and Vortex Generators
Authors: O’Brien James E. , Sohal Manohar S. , Wallstedt Philip C.
Published: November 2004

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with an elliptical tube and one or two delta-winglet pairs. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficients were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over a Reynolds number range based on duct height of 670–6300. Pressure-drop measurements have also been obtained for similar elliptical-tube and winglet geometries, using a separate single-channel, multiple-tube-row pressure-drop apparatus. The pressure-drop apparatus includes four tube rows in a staggered array. Comparisons of heat transfer and pressure-drop results for the elliptical tube versus a circular tube with and without winglets are provided. Mean heat transfer results indicated that the addition of the single winglet pair to the oval-tube geometry yielded significant heat transfer enhancement, averaging 38% higher than the oval-tube, no-winglet case. The corresponding increase in friction factor associated with the addition of the single winglet pair to the oval-tube geometry was very modest, less than 10% at ReDh=500 and less than 5% at ReDh=5000.
Estimating Parameters and Refining Thermal Models by Using the Extended Kalman Filter Approach
Authors: Emery Ashley F.
Published: November 2004

Parameter estimation is based upon a comparison of predicted deterministic model responses to data. The models are often numerical, e.g., finite volume, with intrinsic inaccuracies. In addition, the models typically assume a full knowledge of the physical processes. By using the concept of state variables and employing the extended Kalman filter approach it is possible to include additional effects in the model to achieve better agreement between the model and the data. This paper describes such an approach to the estimation of thermal conductivity in a transiently heated and cooled one-dimensional system and shows that it leads to a resolution of questions about the time behavior of the residuals previously observed in an estimation based upon the least squares analysis.
Thermal Analysis of Laser-Densified Dental Porcelain Bodies: Modeling and Experiments
Authors: Dai K. , Li X. , Shaw L.
Published: November 2004

Thermal analysis of laser densification of a dental porcelain powder bed has been investigated using a three-dimensional thermal finite element model, which encompasses (i) the incoming laser beam power with a Gaussian distribution, (ii) optical pyrometer simulation in addition to the closed-loop temperature control, (iii) powder-to-solid transition, (iv) temperature-dependent thermal convection, and (v) temperature and porosity-dependent thermal conduction and radiation. The simulation results are compared with the experiments. It is found that the predicted temperature distribution in the porcelain body matches the experiments very well. Further, the maximum discrepancy between experimental and simulated pyrometer temperatures is less than 8 percent. The simulation predicts that in order to achieve the desired microstructure of a dense dental porcelain body, the maximum local temperature during laser densification should be below 1573 K or the nominal surface temperature should be below 1273 K. Otherwise, the undesired microstructure (i.e., a leucite-free glass phase) forms.
Importance of Combined Lorentz-Doppler Broadening in High-Temperature Radiative Heat Transfer Applications
Authors: Wang Anquan , Modest Michael F.
Published: November 2004

The importance of combined Lorentz-Doppler (or Voigt) broadening of spectral lines in high-temperature radiative heat transfer applications is investigated. Employing narrow-band transmissivities as the criterion, the critical total pressure below which, and the critical temperature above which Doppler broadening has a significant effect on the absorption coefficient is established for gaseous H2O and CO2.
Three-Dimensional Numerical Simulation on Laminar Heat Transfer and Fluid Flow Characteristics of Strip Fin Surface With X-Arrangement of Strips
Authors: Qu Z. G. , Tao W. Q. , He Y. L.
Published: November 2004

In this paper, a numerical investigation of air side performance of strip fin surface is presented. Three-dimensional numerical computation was made for a model of a two-row finned tube heat exchanger. The tube configuration is simulated with step-wise approximation, and the fin efficiency is also calculated with conjugated computation. Four types of fin surfaces were studied: A-the whole plain plate fin; B-the strip fin with strips located in the upstream part of the fin; C-the strip fin with strips located in the downstream part of the fin; and D-the strip fin with strips covering the whole fin surface. It is found that the strip fin with strips located in the downstream part of the fin surface (fin C) has higher heat transfer rate than that with strips in the upstream part (fin B) at the same conditions, while the pressure drop of fin C is a bit lower than that of fin B. A comprehensive performance comparison was conducted by using the goodness factor and the pumping power consumption per unit surface area. It is revealed that between the two strip fins the performance of fin C is better than fin B with same strip number. Detailed discussion is provided from the view point of synergy between velocity and temperature gradient. It is shown that the synergy between velocity and temperature field becomes worse in the downstream part of the fin surface, and it is this place that enhancement technique is highly needed. The strip location of fin C just fits this situation. The present numerical work provides useful information on where the enhancement element should be positioned.
Numerical and Experimental Investigations of Melting and Solidification Processes of High Melting Point PCM in a Cylindrical Enclosure
Authors: Elgafy Ahmed , Mesalhy Osama , Lafdi Khalid
Published: November 2004

In the present work, a computational model is developed to investigate and predict the thermal performance of high melting point phase change material during its melting and solidification processes within a cylindrical enclosure. In this model the phases are assumed to be homogeneous and a source term, S, arises from melting or solidification process is considered as a function of the latent heat of fusion and the liquid phase fraction. The numerical model is verified with a test problem and an experiment is performed to assess the validity of the assumptions of it and an agreement between experimental and computational results is achieved. The findings show that utilizing of PCMs of high melting points is a promising technique especially in space applications.
Genetic Characterization of the Bile Salt Response in
Lactobacillus plantarum
and Analysis of Responsive Promoters In Vitro and In Situ in the Gastrointestinal Tract
Authors: Bron Peter A. , Marco Maria , Hoffer Sally M. , Van Mullekom Esther , de Vos Willem M. , Kleerebezem Michiel
Published: November 2004

In this paper we describe the growth, morphological, and genetic responses of
Lactobacillus plantarum
WCFS1 to bile. Growth experiments revealed that a stepwise increase in the porcine bile concentration led to a gradual decrease in the maximal growth rate. Moreover, the final density reached by an
L. plantarum
culture growing in MRS containing 0.1% bile was approximately threefold lower than that in MRS lacking bile. The morphology of the cells grown in MRS containing 0.1% bile was investigated by scanning electron microscopy, which revealed that cells clumped together and had rough surfaces and that some of the cells had a shrunken and empty appearance, which clearly contrasted with the characteristic rod-shaped, smooth-surface morphology of
L. plantarum
cells grown in MRS without bile. An
alr
complementation-based genome-wide promoter screening analysis was performed with
L. plantarum
, which led to identification of 31 genes whose expression was potentially induced by 0.1% porcine bile. Remarkably, 11 membrane- and cell wall-associated functions appeared to be induced by bile, as were five functions involved in redox reactions and five regulatory factors. Moreover, the lp_0237 and lp_0775 genes, identified here as genes that are inducible by bile in vitro, were previously identified in our laboratory as important for
L. plantarum
in vivo during passage in the mouse gastrointestinal tract (P. A. Bron, C. Grangette, A. Mercenier, W. M. de Vos, and M. Kleerebezem, J. Bacteriol.
186:
5721-5729, 2004). A quantitative reverse transcription-PCR approach focusing on these two genes confirmed that the expression level of lp_0237 and lp_0775 was significantly higher in cells grown in the presence of bile and cells isolated from the mouse duodenum than in cells grown on laboratory medium without bile.
Transcriptional Activation of
sclA
by Mga Requires a Distal Binding Site in
Streptococcus pyogenes
Authors: Almengor Audry C. , McIver Kevin S.
Published: November 2004

Streptococcus pyogenes
(the group A streptococcus [GAS]) is a medically significant pathogen of humans, causing a range of diseases from pharyngitis to necrotizing fasciitis. Several important GAS virulence genes are under the control of a pleiotropic regulator called Mga, or the multiple gene regulator of GAS, including the gene encoding the streptococcal collagen-like protein, or
sclA
. Analysis of the genome sequence upstream of
sclA
revealed two potential Mga-binding sites with homology to the published Mga-binding element, which were called P
sclA
-I (distal) and P
sclA
-II (proximal) based on their location relative to a predicted start of transcription. Primer extension was used to confirm that the Mga-dependent transcriptional start site for
sclA
was located adjacent to the proximal P
sclA
-II binding site. By using overlapping P
sclA
promoter probes and purified Mga-His fusion protein, it was shown by electrophoretic mobility shift assays that, unlike other Mga-regulated promoters, Mga binds only to a distal DNA-binding site (P
sclA
-I). Binding of Mga to P
sclA
-I could be competed with cold probes corresponding to known Mga-regulated promoters (P
emm
, P
scpA
, and P
mga
) but not with a nonspecific probe or the proximal P
sclA
-II fragment. With the use of a plasmid-based green fluorescent protein transcriptional reporter system, the full-length P
sclA
was not sufficient to reproduce normal Mga-regulated activation. However, studies using a single-copy
gusA
transcriptional reporter system integrated at the native
sclA
chromosomal locus clearly demonstrated that the distal P
sclA
-I binding site is required for Mga regulation. Therefore, P
sclA
represents a new class of Mga-regulated promoters that requires a single distal binding site for activation.
Physiological and Gene Expression Analysis of Inhibition of
Desulfovibrio vulgaris
Hildenborough by Nitrite
Authors: Haveman Shelley A. , Greene E. Anne , Stilwell Claire P. , Voordouw Johanna K. , Voordouw Gerrit
Published: November 2004

A
Desulfovibrio vulgaris
Hildenborough mutant lacking the
nrfA
gene for the catalytic subunit of periplasmic cytochrome
c
nitrite reductase (NrfHA) was constructed. In mid-log phase, growth of the wild type in medium containing lactate and sulfate was inhibited by 10 mM nitrite, whereas 0.6 mM nitrite inhibited the
nrfA
mutant. Lower concentrations (0.04 mM) inhibited the growth of both mutant and wild-type cells on plates. Macroarray hybridization indicated that nitrite upregulates the
nrfHA
genes and downregulates genes for sulfate reduction enzymes catalyzing steps preceding the reduction of sulfite to sulfide by dissimilatory sulfite reductase (DsrAB), for two membrane-bound electron transport complexes (
qmoABC
and
dsrMKJOP
) and for ATP synthase (
atp
). DsrAB is known to bind and slowly reduce nitrite. The data support a model in which nitrite inhibits DsrAB (apparent dissociation constant

K
m

for nitrite = 0.03 mM), and in which NrfHA (

K
m

for nitrite = 1.4 mM) limits nitrite entry by reducing it to ammonia when nitrite concentrations are at millimolar levels. The gene expression data and consideration of relative gene locations suggest that QmoABC and DsrMKJOP donate electrons to adenosine phosphosulfate reductase and DsrAB, respectively. Downregulation of
atp
genes, as well as the recorded cell death following addition of inhibitory nitrite concentrations, suggests that the proton gradient collapses when electrons are diverted from cytoplasmic sulfate to periplasmic nitrite reduction.
Two Outer Membrane Proteins Are Required for Maximal Type I Secretion of the
Caulobacter crescentus
S-Layer Protein
Authors: Toporowski Michael C. , Nomellini John F. , Awram Peter , Smit John
Published: November 2004

Transport of RsaA, the crystalline S-layer subunit protein of
Caulobacter crescentus
, is mediated by a type I secretion mechanism. Two proteins have been identified that play the role of the outer membrane protein (OMP) component in the RsaA secretion machinery. The genes
rsaF
a
and
rsaF
b
were identified by similarity to the
Escherichia coli
hemolysin secretion OMP TolC by using the
C. crescentus
genome sequence. The
rsaF
a
gene is located several kilobases downstream of the other transporter genes, while
rsaF
b
is completely unlinked. An
rsaF
a
knockout had ∼56% secretion compared to wild-type levels, while the
rsaF
b
knockout reduced secretion levels to ∼79%. When expression of both proteins was eliminated, there was no RsaA secretion, but a residual level of ∼9% remained inside the cell, suggesting posttranslational autoregulation. Complementation with either of the individual
rsaF
genes by use of a multicopy vector, which resulted in 8- to 10-fold overexpression of the proteins, did not restore RsaA secretion to wild-type levels, indicating that both
rsaF
genes were required for full-level secretion. However, overexpression of

rsaF
a

(with normal
rsaF
b
levels) in concert with overexpression of
rsaA
resulted in a 28% increase in RsaA secretion, indicating a potential for significantly increasing expression levels of an already highly expressing type I secretion system. This is the only known example of type I secretion requiring two OMPs to assemble a fully functional system.
Phenylphosphate Synthase: a New Phosphotransferase Catalyzing the First Step in Anaerobic Phenol Metabolism in
Thauera aromatica
Authors: Schmeling Sirko , Narmandakh Ariun , Schmitt Oliver , Gad'on Nasser , Schühle Karola , Fuchs Georg
Published: November 2004

The anaerobic metabolism of phenol in the beta-proteobacterium
Thauera aromatica
proceeds via
para
-carboxylation of phenol (biological Kolbe-Schmitt carboxylation). In the first step, phenol is converted to phenylphosphate which is then carboxylated to 4-hydroxybenzoate in the second step. Phenylphosphate formation is catalyzed by the novel enzyme phenylphosphate synthase, which was studied. Phenylphosphate synthase consists of three proteins whose genes are located adjacent to each other on the phenol operon and were overproduced in
Escherichia coli
. The promoter region and operon structure of the phenol gene cluster were investigated. Protein 1 (70 kDa) resembles the central part of classical phosphoenolpyruvate synthase which contains a conserved histidine residue. It catalyzes the exchange of free [
14
C]phenol and the phenol moiety of phenylphosphate but not the phosphorylation of phenol. Phosphorylation of phenol requires protein 1, MgATP, and another protein, protein 2 (40 kDa), which resembles the N-terminal part of phosphoenol pyruvate synthase. Proteins 1 and 2 catalyze the following reaction: phenol + MgATP + H
2
O→phenylphosphate + MgAMP + orthophosphate. The phosphoryl group in phenylphosphate is derived from the β-phosphate group of ATP. The free energy of ATP hydrolysis obviously favors the trapping of phenol (

K
m

, 0.04 mM), even at a low ambient substrate concentration. The reaction is stimulated severalfold by another protein, protein 3 (24 kDa), which contains two cystathionine-β-synthase domains of unknown function but does not show significant overall similarity to known proteins. The molecular and catalytic features of phenylphosphate synthase resemble those of phosphoenolpyruvate synthase, albeit with interesting modifications.
Bacteriophage and Phenotypic Variation in
Pseudomonas aeruginosa
Biofilm Development
Authors: Webb Jeremy S. , Lau Mathew , Kjelleberg Staffan
Published: November 2004

A current question in biofilm research is whether biofilm-specific genetic processes can lead to differentiation in physiology and function among biofilm cells. In
Pseudomonas aeruginosa
, phenotypic variants which exhibit a small-colony phenotype on agar media and a markedly accelerated pattern of biofilm development compared to that of the parental strain are often isolated from biofilms. We grew
P. aeruginosa
biofilms in glass flow cell reactors and observed that the emergence of small-colony variants (SCVs) in the effluent runoff from the biofilms correlated with the emergence of plaque-forming Pf1-like filamentous phage (designated Pf4) from the biofilm. Because several recent studies have shown that bacteriophage genes are among the most highly upregulated groups of genes during biofilm development, we investigated whether Pf4 plays a role in SCV formation during
P. aeruginosa
biofilm development. We carried out immunoelectron microscopy using anti-Pf4 antibodies and observed that SCV cells, but not parental-type cells, exhibited high densities of Pf4 filaments on the cell surface and that these filaments were often tightly interwoven into complex latticeworks surrounding the cells. Moreover, infection of
P. aeruginosa
planktonic cultures with Pf4 caused the emergence of SCVs within the culture. These SCVs exhibited enhanced attachment, accelerated biofilm development, and large regions of dead and lysed cells inside microcolonies in a manner identical to that of SCVs obtained from biofilms. We concluded that Pf4 can mediate phenotypic variation in
P. aeruginosa
biofilms. We also performed partial sequencing and analysis of the Pf4 replicative form and identified a number of open reading frames not previously recognized in the genome of
P. aeruginosa
, including a putative postsegregational killing operon.
Crystal Structure of the PdxY Protein from
Escherichia coli
Authors: Safo Martin K. , Musayev Faik N. , Hunt Sharyn , di Salvo Martino L. , Scarsdale Neel , Schirch Verne
Published: November 2004

The crystal structure of
Escherichia coli
PdxY, the protein product of the
pdxY
gene, has been determined to a 2.2-Å resolution. PdxY is a member of the ribokinase superfamily of enzymes and has sequence homology with pyridoxal kinases that phosphorylate pyridoxal at the C-5′ hydroxyl. The protein is a homodimer with an active site on each monomer composed of residues that come exclusively from each respective subunit. The active site is filled with a density that fits that of pyridoxal. In monomer A, the ligand appears to be covalently attached to Cys122 as a thiohemiacetal, while in monomer B it is not covalently attached but appears to be partially present as pyridoxal 5′-phosphate. The presence of pyridoxal phosphate and pyridoxal as ligands was confirmed by the activation of aposerine hydroxymethyltransferase after release of the ligand by the denaturation of PdxY. The ligand, which appears to be covalently attached to Cys122, does not dissociate after denaturation of the protein. A detailed comparison (of functional properties, sequence homology, active site and ATP-binding-site residues, and active site flap types) of PdxY with other pyridoxal kinases as well as the ribokinase superfamily in general suggested that PdxY is a member of a new subclass of the ribokinase superfamily. The structure of PdxY also permitted an interpretation of work that was previously published about this enzyme.
Initial Phases of Biofilm Formation in
Shewanella oneidensis
MR-1
Authors: Thormann Kai M. , Saville Renée M. , Shukla Soni , Pelletier Dale A. , Spormann Alfred M.
Published: November 2004

Shewanella oneidensis
MR-1 is a facultative Fe(III)- and Mn(IV)-reducing microorganism and serves as a model for studying microbially induced dissolution of Fe or Mn oxide minerals as well as biogeochemical cycles. In soil and sediment environments,
S. oneidensis
biofilms form on mineral surfaces and are critical for mediating the metabolic interaction between this microbe and insoluble metal oxide phases. In order to develop an understanding of the molecular basis of biofilm formation, we investigated
S. oneidensis
biofilms developing on glass surfaces in a hydrodynamic flow chamber system. After initial attachment, growth of microcolonies and lateral spreading of biofilm cells on the surface occurred simultaneously within the first 24 h. Once surface coverage was almost complete, biofilm development proceeded with extensive vertical growth, resulting in formation of towering structures giving rise to pronounced three-dimensional architecture. Biofilm development was found to be dependent on the nutrient conditions, suggesting a metabolic control. In global transposon mutagenesis, 173 insertion mutants out of 15,000 mutants screened were identified carrying defects in initial attachment and/or early stages in biofilm formation. Seventy-one of those mutants exhibited a nonswimming phenotype, suggesting a role of swimming motility or motility elements in biofilm formation. Disruption mutations in motility genes (
flhB
,
fliK
, and
pomA
), however, did not affect initial attachment but affected progression of biofilm development into pronounced three-dimensional architecture. In contrast, mutants defective in mannose-sensitive hemagglutinin type IV pilus biosynthesis and in pilus retraction (
pilT
) showed severe defects in adhesion to abiotic surfaces and biofilm formation, respectively. The results provide a basis for understanding microbe-mineral interactions in natural environments.