bluuebunny/crossref_metadata_2025 huggingface dataset:
Rehydration of Food Powders
Authors: Hogekamp S. , Schubert H.
Published: August 2003

In the vast majority of cases, powdered foods are intended for rehydration with water or, respectively, an aqueous liquid. An ideal powder should be wetted quickly and thoroughly, sink into the liquid rather than float on the surface and disperse/dissolve within a short period of time without lump formation. This ideal behaviour is difficult to achieve, since the manufacturing processes usually yield particles of rather small size and/or unfavourable structure. The presence of fat or oil may further decrease the wettability. Food powder manufacturers are therefore struggling to improve the properties of such products, e.g., by agglomeration or by adding wetting agents to their recipes. Other materials may be so hydrophilic that they dissolve almost instantly, making them equally unwettable if applied in larger quantities. This work overviews current methods of characterising the wetting, sinking and dispersing behaviour of powdered foods used in our laboratory, the majority also having been developed there. Objective measuring methods, in conjunction with some basic knowledge of the mechanisms of wetting bulk materials, are indispensable tools for improving the properties of powdered products. The usefulness of these measuring methods and their limitations are discussed by means of measurement examples carried out on a variety of powdered foods. Simple measuring methods may typically be used for quality control purposes, provided that a more general understanding of a powder's behaviour has been gained before by use of more elaborate methods. It is thus generally possible to control the quality of consumer products, which are usually used in small quantities, using rather simple devices. The characterisation of powders intended for large scale application requires considerably more effort and, especially when the dispersion ability of a powder is to be described, the proper choice of measuring principle.
Muscle Foods: Water, Structure and Functionality
Authors: Toldrá F.
Published: August 2003

Main constituents of skeletal muscle are water, protein, fat, carbohydrate and other soluble compounds. The amount of water is usually found in the range 70-80%. Part of this water is found in free form while the rest is bound to proteins, especially myofibrillar proteins, through charged and polar groups. The amount of immobilised water depends on the available space within the myofibrillar structure and, in fact, the volume of myofibrils is decisive to the water-binding capacity of the muscle. Some variations exist between muscles due to the types of muscle fibres, degree of fibre contraction and pre-rigor pH. The water retention will also depend on the ultimate pH reached after rigor mortis and this will have a strong influence on the activity of muscle enzymes involved in proteolysis and lipolysis during ageing and further processing. Variations may be also expected between animal or fish species and age at slaughter. It is of primary importance to understand metabolic processes in post-mortem muscle as they will directly influence water-binding and thus, the relative amount of drip loss.
Mass Transfer Behavior of Plant Tissues During Osmotic Dehydration
Authors: Le Maguer M. , Shi J. , Fernandez C.
Published: August 2003

Biological structures and behavior of biomaterials are difficult to describe in quantitative terms. In a process such as osmotic dehydration of plant tissues, these complex structures pose a challenging factor in the optimization process and design of equipment. The structure and properties of the tissues affect the mass transfer phenomena occurring in plant tissues during osmotic dehydration. The purpose of this study was to develop a method to classify the mass transfer behavior of different plant materials during osmotic dehydration. The method of classification was based on the description of the material behavior according to easily measurable parameters. These parameters were water loss and solids gain. By fitting an inverse polynomial model to the kinetics data, rates and fluxes of mass transfer were calculated. Two methods of classification were developed based on the rates and fluxes of mass transfer. The method based on fluxes accommodated for the different geometries of the samples. The two methods were combined to calculate the value of, which is the ratio of the bulk flow transport to diffusion transport at the interface of the solution at time 0. The seven kinds of fresh fruit materials that were analyzed were divided into three classes. Their mass transfer behaviors were then described in quantitative terms as either “fast”, “average” or “slow”. These methods of classification have provided description of the behavior of various plant tissues during osmotic dehydration.
Phase Transitions and Functionality of Enzymes and Yeasts in Dehydrated Matrices
Authors: Mazzobre M. F. , Hough G. , Buera M. P.
Published: August 2003

Enzymes and yeast cells were chosen as model probes to investigate functional changes taking place in freeze-dried systems containing different sugars, polymers and salts undergoing phase/state transitions. Differential scanning calorimetry, X-rays diffraction and microscopy provided information on molecular and microscopic changes. Enzyme stability depended on the amorphous structure and non-reducing characteristics of sugars, and residual activity was very low in the super-cooled region when sugars crystallised. The addition of polymers or salts extended the protective effect of sugars to the super-cooled region by delaying crystallisation. Starch provided adequate protection to the enzyme at high water content and low temperatures, where stability was completely lost in other systems. The presence of low-molecular-weight saccharides during drying and storage appeared to be the critical factor protecting cell viability. State diagrams are helpful to analyse the combined effects of temperature, water content and physical state on the stability of biomaterials but there is no direct relationship between overall physical properties and the kinetics of deteriorative changes. Additional information on molecular interactions is relevant to define strategies to preserve the functionality of biomolecules.
Drying in Pharmaceutical and Biotechnological Industries
Authors: Guerrero M. , Albet C. , Palomer A. , Guglietta A.
Published: August 2003

The process used for drying pharmaceuticals has a high impact on the final product characteristics, both on the active ingredient (high chemical purity product) and the end drug product (complexgalenic formulation). For example, it is well-known that there is a direct relation between the absorption of the active ingredient and its characteristic crystalline or polymorphic form. In some cases, the latter is related to the procedure and conditions of drying. The consequences of the process used to dry a pharmaceutical product may be different depending on the development phase: pre-clinical studies or manufacture (production). The drying process may greatly influence the quality of the drug substances in several aspects: the polymorphic form of the active ingredient, the structural changes that may have an effect on the activity of the substance, the degradation products formed due to the drying conditions and the presence of residual solvents undesirable or above the permitted limits after drying. Consequently, it is important to know the influence of all the factors and to establish the product specifications, as well as the nature and limits of residual solvents, in agreement with current regulations.
Topologies of Becoming
Authors: Kymäläinen Päivi
Published: August 2003

The relations between texts and the world are at the forefront of cultural geography. Along with the cultural and linguistic turns in geography, the aims of searching for meanings have been problematized, and the awareness of the complicated nature of the textures of place has at the same time been widened. What does it mean if the meanings of place are interpreted as becoming instead of being, if feeling is emphasized instead of seeing, and if there still remain nondiscursive elements that disrupt the supposed order in writing places? The aims of this article are to consider the current discussions on the textuality of place and to give some openings for writing places and understanding the limits of that writing. These questions are connected here to the deconstructive and humanistic efforts to write places by inhabiting them or by crossing their discursive boundaries.
The Architectural Edifice and the Phantoms of History
Authors: Lozanovska Mirjana
Published: August 2003

Starting with the literal and physical role of the “ground,” this article attempts to bring this “ground” into a discursive arena. In particular, the author is thinking about the period at the end of a war, the period in between destruction and reconstruction, exemplified in some classic postwar films in which the architecture of the city is in a state of ruin—deformed, eroded, and dark—but there is no further destruction. The article calls this period “a gap of history” and its investigation is set against a claim that architecture is a reconstructive practice, that it is enlightening and aspiring. History, on the other hand, is captured by scenes of the battlefield and dominated by a narrative of war and destruction. The article makes reference to the real and fantasy desire for destruction (war and history) and reconstruction (architecture), and how through the connecting plane of the ground architecture is entangled in war and history of destruction as it figures in reconstruction. Architecture is contingent on history as discursive—history that is not unified, fixed, or evolutionary but rather contested and rewritten within a conflictual battlefield.
'Would You Consider Yourself a Healthy Person?' : Using Focus Groups to Explore Health as a Moral Phenomenon
Authors: Crossley Michele L.
Published: August 2003

Recent psychological, sociological and cultural theory has suggested that health has become a moral phenomenon. The main aim of this paper is to illustrate how focus groups constitute a particularly useful method of investigating the way in which people routinely engage in moral reasoning in the course of conversations and debates regarding health related issues. The four focus groups drawn upon in this study formed part of a larger study whose aim was to explore attitudes towards health and a theoretically postulated increasing ‘resistance’ to health promotion amongst the general public. Accordingly, the focus groups covered themes such as: concepts of healthy and unhealthy; individual responsibility for health; attitudes and responses to health promotion; public trust in medicine, science, doctors and health information; and the relationship between health, individual freedom and government intervention.
Illness Representations in Families with a Chronically Ill Adolescent: Differences between Family Members and Impact on Patients’ Outcome Variables
Authors: Salewski Christel
Published: August 2003

The impact of parents’ illness representations on well-being and illness-related strain of adolescents suffering from a chronic skin disease was examined. Because family characteristics have proved to be important for coping, adolescents’ perceived family cohesion was also assessed. Five categories of illness representations (causes, control, timeline, curability, and effective treatments) were assessed from 30 adolescents and their parents. Comparisons revealed differences between family members’ illness representations. Perceived family cohesion was a good predictor of adolescents’ wellbeing and strain, whereas parents’ illness representations had only little impact. In families with high similarity between the parents’ illness representations, the adolescents reported more well-being. Results are discussed with regard to developmental characteristics of adolescence, nature of outcome variables and methodological problems.
The Transformation of Social Representations of Chronic Disease in a Self-Help Group
Authors: Krause Mariane
Published: August 2003

A Participant Action Research process was carried out with individuals affected by Inflammatory Bowel Disease, more specifically Crohn’s Disease and Ulcerative Colitis. The results show evidence of a transformation of social representations of disease. ‘Normalization’ is the central component of the transformation, indicating the achievement of a more restricted representation of the illness. This change is an attitudinal modification, which is characterized by higher tolerance of the disease— accepting its chronic nature and the limitations it imposes on daily life—, acceptance of the possibility of being supported by others in facing the disease, and the recognition of a transformational process that involves different stages in dealing with and accepting the disease.
Managing the Euro
Authors: Kaltenthaler Karl
Published: August 2003

For a year following the launch of the euro, the European Central Bank (ECB) seemed indifferent to the currency's depreciation. Then the ECB changed to a policy position of trying to bolster the external value of the euro. This paper seeks to explain these patterns of positions on the ECB's external monetary policy. I argue that the ECB's policy on the exchange rate is a function of its commitment to domestic price stability in the euro zone. In other words, the ECB's concern with the euro's exchange rate centers solely on what that exchange rate can do to inflation. This focus on price stability is a function of the interests of the ECB in maintaining its own image of competence in European society.
Elaborating Analytic Ethnography
Authors: Snow David A. , Morrill Calvin , Anderson Leon
Published: August 2003

Among the diverse styles of qualitative methodology is what John Lofland referred to as `analytic ethnography.' In contrast to the traditional interpretive style that attempts to get at the crux of `what is going on', to the more formal approach that seeks to identify the cognitive rules undergirding behavior, and to the more recent postmodern preoccupation with individual experience and voices, analytic ethnography seeks to develop systematic and generic understandings and propositions about social processes. In this article we elaborate analytic ethnography beyond Lofland's original statement by articulating how it can contribute to theoretical development through conceptual refinement and theoretical extension as well as through the more traditional development of grounded theory. We discuss and illustrate these three strategies for theoretical development by drawing on various field studies, including our own, and by suggesting the conditions propitious to each strategy.
The Social Basis of Loss and Grief
Authors: Bevan Denise , Thompson Neil
Published: August 2003

* Summary: A review of the neglected area of the relationship between loss and grief and the less well-documented areas of discrimination in relation to age, disability and sexuality. * Findings: There is an extensive and long-standing literature base relating to loss and grief. However, the major focus of such work is predominantly psychological and individualistic in its focus. Only recently a solid body of work relating to the sociological dimensions of loss and grief has begun to build up. This new literature has largely followed the pattern of the development of anti-discriminatory practice in social work, with a major emphasis on class, race and gender, and little attention paid to the less well-established forms of discrimination such as ageism, disablism and heterosexism. * Applications: This article explores the relationship between these three forms of discrimination and loss and grief, with a view to establishing the importance of developing a broad-based anti-discriminatory practice in this important area of social work.
Managing Risk and Uncertainty in Social Work
Authors: Stalker Kirsten
Published: August 2003

* Summary: This review, which draws mainly but not exclusively on UK material, explores the social work literature on managing risk and uncertainty, with emphasis on community care. Risk has become a major, if not over-arching, preoccupation in social work, reflected in a huge upsurge of written material. * Findings: The article briefly traces the historical development of the concepts of risk and uncertainty and identifies a number of theoretical frameworks, noting that the risk society is marked by change, uncertainty, and a reduced faith in experts. Some commentators have drawn out the implications of these ideas for social work. At present, however, we lack a social model of risk. The article describes a continuum of risk management, marked by controlling attitudes at one end and more empowering approaches at the other. The former is evident in risk avoidance strategies, the latter in positive risk-taking; the literature on each is reviewed. * Applications: The views of service users are largely absent from the literature but their role in taking and managing risks on an everyday basis should not be overlooked, nor their potential to play a more significant role in the process. Pointers for future research are identified.
`Where are you Really from?': Representation, Identity and Power in the Fieldwork Experiences of a South Asian Diasporic
Authors: Henry Marsha Giselle
Published: August 2003

Feminist accounts of fieldwork have often been concerned with issues of representation, both of the researched and the researcher, exposing some of the complications that arise when the researcher must make critical decisions about representing herself to her research participants. These accounts demonstrate that a fieldworker's identity does in fact impact upon the research process and product, challenging notions of researcher objectivity and neutrality. I contribute to feminist debates by complicating the process of representation and the power and problem of naming; identity and its impact upon the research process; and the field as a place of complex power structures, which can produce questions that seem all too familiar. One of the questions raised in relation to representation, identity and the field is one that I have been asked virtually all my life, but which has different meanings in different contexts. My research participants often asked, `where are you really from?' This question in the context of the feminist literature on methodology has enabled me to analyse some of the difficulties and problems I faced in doing fieldwork and to develop a different conceptualization of the research process and research participants. Finally, it has also demonstrated some of the difficulties that our current and limited language of race, ethnicity and nationality pose for first generation South Asian researchers.
Reading and Writing Performance
Authors: Denzin Norman K.
Published: August 2003

Criteria for evaluating experimental ethnographic texts are reviewed. Subversive, resistance narratives are foregrounded. While the focus is primarily on North American work, scholarship by non-American scholars is reviewed as well, including the arguments by indigenous scholars.
Book Reviews
Authors: Hopkins Lewis D.
Published: August 2003

Planning Theory is a vehicle for exploring diverse views of the nature and purpose of planning. In this issue we present two reviews of an account of developments in European spatial planning. The book being reviewed is very much an insider's account, and we felt there would be value in juxtaposing reviews by scholars within and outside the European Union; reviewers who also had distinctive, and rather different views of the nature of planning, and the role of plans within that process.
Self-Directed Care: An Evaluation
Authors: Young Heather M. , Sikma Suzanne K.
Published: August 2003

This study evaluates self-directed care (SDC), a program introduced in 2000 in Washington State to promote consumer direction in community-based services for persons with disabilities. This report summarizes findings on satisfaction with the program, service quality and consumer safety, instances and outcomes of consumer abuse and neglect, and staffing issues in SDC. Methods included surveys and interviews with participants in SDC and review of existing databases, complaint logs and reports, and departmental field notes. Major findings were no negative outcomes for consumers, improvements in quality of life and quality of care for consumers, high satisfaction, perception of SDC as a valued option, and the challenges of ensuring adequate staffing.
Latex Hazards: Setting Policy
Authors: Smith Karleen , Wallace Ann , Smith-Campbell Betty
Published: August 2003

This past decade, natural rubber latex hypersensitivity has become an increasing concern for the health care industry and nurses. With the adoption of universal precautions in the late 1980s and increased glove use, the incidence of latex allergy has increased dramatically. There have been legislative initiatives to label all products containing natural rubber latex, but the use of latex in health care agencies has not been restricted or regulated in any way. This article reviews the historical perspective of the latex issue, provides strong arguments for banning latex gloves in all health care facilities, and explores some political, social, and legal issues involved in banning latex gloves.
Effect of Fluorochemicals on Flame-Retardant Fibers
Authors: Kasturiya Nishkam , Katiyar Priyanka , Bhargava G. S. , Nishkam Anita
Published: August 2003

To develop durable flame, water and oil repellent fabrics, a study was undertaken using fluorochemicals as water and oil repellent agents on inherently flame-retardant fibers. The treated samples were leached for 30 and 60 min to evaluate durability of the chemical treatment. The fluorochemical treatments produced durable fabrics that were simultaneously flame retardant and water and oil repellent. The effect of fluorochemicals on the thermal chemistry of inherently flame-retardant fibers was studied using thermogravimetric analysis (TGA). The studies showed that the fluorochemical treatment does not affect the thermal chemistry of the flame-retardant fibers.
Textile Back-Coating Environmental Challenges for the UK Furnishing Fabrics Industry: Release and Exposure of Flame Retardant Species
Authors: Stevens G. C. , Horrocks A. R.
Published: August 2003

European priority-chemical risk assessments of flame retardants, UK work on associated ecotoxicological risks, the findings of the US NAS/NRC subcommittee report on the risk assessment of flame retardant chemicals and the related work of the US CPSC, have revealed a distinct absence of good quality peer reviewed information on the release of flame retardants from common consumer product materials. Such lack of information for human exposure by dermal, oral and inhalation routes and for environmental ecotoxicology assessments can have a significant impact on the outcome of current and future prospective approaches to risk assessment. This is illustrated for some current risk assessment methodologies. Flame retardant release and exposure measurements may obviate the need for more expensive and time-consuming toxicology work to arrive at risk assessments that contain a high degree of certainty. We discuss flame retardant release and exposure research needs and describe recently initiated work to establish release behaviour and the effects of ageing and wear on the release and exposure of flame retardants used in upholstered furniture materials. The practical consequences of having a better understanding of the release and exposure of flame retardants is also discussed.
Behavior of an Intumescent System for Flame Retardant Materials Coated on Polypropylene Textiles
Authors: Carole Magniez , Andre Dubois , Moise Vouters , Rene Delobel , Franck Poutch
Published: August 2003

The use of flammable materials in house interiors, building or public transport constitutes a potential hazard for people in case of fire. The need for consumer protection, coupled with the new regulations and environmental concerns, increases the interest in flame-retardant treatments, in particular intumescent systems. The aim of this work was to develop innovative synthetic textiles, bonded with flame-retardant back-coating at laboratory scale, and to develop a methodology to study the fire behavior of these kinds of materials. Our work points out the differences in fire behavior of polypropylene textile structures in comparison with plastics. Fire behavior was validated on cone calorimeter equipment. As a consequence, this study shows how after reducing the rate of heat release, which is one of the parameters of the new regulations, polypropylene fibers can be used for flame retardant materials.
Modern Approaches for Intelligent Surface Modification
Authors: Textor Torsten , Bahners Thomas , Schollmyer Eckhard
Published: August 2003

Increasing demand for specialized textiles, especially high performance technical products, can be observed world-wide. Therefore, intensive research work concentrates on the development of new methods for specific modification or functionalization of synthetic fiber surfaces to achieve improved or even new properties. Two of these methods are described in detail. One is an innovative method for textile finishing that involves modification of fiber material with organically modified ceramics, which combine advantages of organic polymers and ceramics. These materials are part of the nanotechnology. Another approach to create specific surface properties involves photochemical and/or physical modifications using excimer-UV-light sources. These special light sources emit monochromatic radiation that allows well-defined modification processes.
Understanding Puncture Resistance and Perforation Behavior of Packaging Laminates
Authors: Lange Jakob , Mokdad Haroun , Wysery Yves
Published: August 2003

This paper presents the development of a method to measure damage to packaging laminates by penetration. A hemispherical probe was shown to provide the most reproducible results and the rate of loading was found to be a small factor. The puncture mechanism for different types of laminates was examined. It was shown that the presence of paper in the structure has a decisive effect on puncture resistance. For paper-based laminates, the paper layer limits the strength by rupturing first and then producing premature rupture of the other layers; the result is a 4-10-fold improvement in strength by eliminating paper as an outer layer. For laminates without paper, all layers rupture together so changing the composition of the non-paper layers has a direct influence on the puncture resistance. The direction of the penetration through the laminate usually has an effect on the energy to puncture.
Agricultural Films: Types and Applications
Authors: Laverde German
Published: August 2003

Many applications are covered under this category, but the most typical are greenhouse covering, low tunnel film, mulch film, soil sterilization and fumigation film, silage film, film for water reservoirs, and film for packaging and protection. Although they have their application in the agricultural industry in common, they each have particular specifications and demands depending on the effects desired; these are described in this paper. Data is also provided concerning resin consumption and market share as well as the method of manufacture that is used for agricultural films, which are primarily made from polyolefins.
Chemokines in bronchoalveolar lavage fluid in summer-type hypersensitivity pneumonitis
Authors: Sugiyama Y , Kasahara T , Mukaida N , Matsushima K , Kitamura S
Published: August 2003

Hypersensitivity pneumonitis (HP) is a granulomatous interstitial lung disease caused by the inhalation of a variety of antigens and is characterized by a dramatic accumulation of inflammatory cells, including neutrophils, lymphocytes and macrophages, in the lung. The mechanisms implicated in the inflammatory cell recruitment observed in hypersensitivity pneumonitis are unknown. We examined the concentrations of two important chemokines, interleukin-8 (IL-8) and monocyte chemoattractant protein-1/monocyte chemotactic and activating factor (MCP-1/MCAF), in the bronchoalveolar lavage fluid (BALF) of patients with summer-type hypersensitivity pneumonitis (n = 8), and compared them with those in patients with sarcoidosis (n = 13) and with controls (n = 8). In the BALF of summer-type hypersensitivity pneumonitis, the levels both of IL-8 and MCP-1 were significantly increased compared with levels measured in control subjects. On the other hand, compared to the control value, the MCP-1 level in the BALF of the sarcoidosis patients was significantly increased, but IL-8 was only slightly and nonsignificantly increased. Since IL-8 is a chemoattractant for neutrophils and T-lymphocytes, whereas MCP-1 acts mainly on monocytes/macrophages, our findings may indicate that these two chemokines participate in the cellular accumulation observed in hypersensitivity pneumonitis.
Prevalence and characteristics of children with chronic respiratory symptoms in eastern Finland
Authors: Timonen KL , Pekkanen J , Korppi M , Vahteristo M , Salonen RO
Published: August 2003

The objective of the present study was to assess the prevalence of asthma and asthma-related symptoms in Finland. We also wondered whether chronic cough may be an indicator of occult asthma. Prevalence and characteristics of children with doctor-diagnosed asthma and chronic respiratory symptoms were investigated in 7-12 year old school children from eastern Finland by using a questionnaire on respiratory symptoms. In addition, skin-prick tests, flow-volume spirometry, and serum total immunoglobulin E (IgE) measurements were performed in children reporting chronic respiratory symptoms. The parent-reported prevalence of doctor-diagnosed asthma was 4.4%, of wheezing 5.4%, of attacks of shortness of breath with wheezing 4.6%, and of dry cough at night 12%. Children with dry cough only (n = 195) had less frequent parental asthma, self-reported allergies, daily respiratory medication, and moisture stains or molds at home than asthmatic children (n = 180), but these findings were more frequent than among asymptomatic children (n = 2,169). The prevalence of at least one positive skin-prick test result was 79% among the asthmatic children and 55% among children with dry cough only. There were no differences between the two symptom groups in serum total IgE levels and spirometric lung functions, except in maximal mid-expiratory flow (MMEF) values, which were significantly lower among children with asthmatic symptoms. The present results support the hypothesis that chronic cough may be an indicator of occult asthma. Therefore, to improve the sensitivity of respiratory questionnaires designed to detect asthma, they should also include questions on chronic cough.(ABSTRACT TRUNCATED AT 250 WORDS)
PDE isoenzymes as targets for anti-asthma drugs
Authors: Schudt C , Tenor H , Hatzelmann A
Published: August 2003

Phophodiesterase (PDE) isoenzyme profiles of human cell preparations and tissues have been analysed by a semiquantitative method using selective PDE inhibitors and activators. Neutrophils, eosinophils and monocytes contain PDE IV exclusively. Lymphocytes, alveolar macrophages and endothelial cells contain PDE IV and PDE III, and in addition, PDE I is measured in macrophages and PDE II in endothelial cells. These basal cell-specific PDE isoenzyme profiles appear to be modified by: 1) substrate concentration; 2) kinase-dependent phosphorylation; and 3) regulated rate of synthesis. Therefore, PDE isoenzyme profiles represent dynamic patterns, which apparently adapt to pathological and environmental conditions. In parallel functional studies, the influence of mono-selective (rolipram, PDE IV; motapizone, PDE III), dual-selective (zardaverine) and non-selective (theophylline) PDE inhibitors were compared. Corresponding to isoenzyme analysis, it was demonstrated that both PDE III and PDE IV have to be inhibited for complete suppression of either tumour necrosis factor-alpha (TNF-alpha) release from macrophages, or lymphocyte proliferation (PDE III/IV cells). In eosinophils (PDE IV cells) platelet-activating factor (PAF)-induced chemotaxis or C5a-stimulated degranulation are only weakly inhibited by rolipram alone. After addition of a beta 2-agonist, however, the efficacy of rolipram is enhanced due to concomitant influence of synthesis and breakdown of cyclic adenosine monophosphate (cAMP). Theophylline inhibits PDE isoenzyme activities and functions of inflammatory cells with similar potency, and exhibits higher functional efficacy as compared to rolipram.
Drug-resistant tuberculosis in the 1990s
Authors: Yew WW , Chau CH
Published: August 2003

There has been an upsurge of tuberculosis in many parts of the world in the past decade. The high rates of drug-resistant tuberculosis currently reported in many countries are alarming. The most catastrophic phenomenon is the emergence of multidrug-resistant strains of Mycobacterium tuberculosis. These organisms have caused epidemic outbreaks in nosocomial and health-care settings in the USA and some European countries. In addition to immigration, poverty, alcoholism and intravenous substance abuse, human immunodeficiency virus (HIV) infection has also had a significant impact on the prevalence of drug resistance, since amongst these patient groups a common factor giving rise to drug resistance is noncompliance. Rapid drug susceptibility tests are needed, and effective chemotherapy regimens with newly developed drugs in combination with traditional second-line antituberculosis agents for established multidrug-resistant tuberculosis are urgently being sought. There is also a quest for other novel modalities of therapy. Measures should be actively adopted to prevent the development of drug resistance. Well formulated short-course chemotherapy as initial treatment and ensurance of compliance are the most important components. The organization of a national tuberculosis control programme with a sound and adequately functioning infrastructure remains the most effective strategy to combat the resurgence of tuberculosis and to curtail drug resistance.
Neurophysiology of the cough reflex
Authors: Widdicombe JG
Published: August 2003

Cough is due to activation of sensory receptors in the larynx and lower respiratory tract, sending impulses to the brainstem. The central organization of cough is poorly understood. The afferent pathways for cough are from receptors in and under the epithelium of the airways. These receptors are rapidly adapting, with thin myelinated fibres in the vagus nerves, which can be directly stimulated by tussive agents. Activation of C-fibre receptors in the airway releases sensory neuropeptides. These cause neurogenic inflammation and may activate rapidly adapting receptors to cause cough. The central connections of the C-fibre receptors inhibit cough. Thus, the sensitivity of the cough reflex and its pattern of response is due to a complex interaction between C-fibre receptors and rapidly adapting receptors, with peripheral and central nervous interactions. How these mechanisms apply to clinical cough in patients is at present poorly understood, but is beginning to be clarified.
Chylothorax and chylous ascites due to heart failure
Authors: Villena V , de Pablo A , Martin-Escribano P
Published: August 2003

Chylous ascites and chylothorax have rarely been reported as a consequence of severe right heart failure. To our knowledge, this is the first case report of both disorders occurring as a result of ischaemic cardiomyopathy. The autopsy findings and possible mechanisms of production are discussed.
Inflammatory bronchial polyps associated with asthma: resolution with inhaled corticosteroid
Authors: Niimi A , Amitani R , Ikeda T , Kubo Y , Tanaka E , Kuze F
Published: August 2003

In a 50 year old man who complained of cough and sputum, a small endobronchial tumour was found in the left main bronchus and was biopsied via bronchoscopy. The histological diagnosis was inflammatory polyp with marked infiltration of eosinophils. Six years later, the patient developed asthma. At the same time, another polyp was found in the posterior basal bronchus of the right lower lobe. The appearance of the first polyp was unchanged endoscopically and histologically. Inhalation of beclomethasone dipropionate, 200 micrograms b.i.d., was started and symptoms of asthma soon subsided. In addition, the two polyps regressed and eventually disappeared after one year of treatment. Inhaled corticosteroids, being noninvasive and relatively safe, appear to be a possible therapeutic option in inflammatory bronchial polyps, especially in cases where the patient has asthma as an underlying condition, or the polyps are small and their management is not urgent.
Cost-benefit analysis of mollusc eating in a shorebird I. Foraging and processing costs estimated by the doubly labelled water method
Authors: Piersma Theunis , Dekinga Anne , Gils Jan A. van , Achterkamp Bart , Visser G. Henk
Published: August 2003

Although the energy costs of foraging and food processing in vertebrates may be considerable, they have rarely been quantified separately. Here we present estimates for both cost factors based on a series of trials with a shorebird, the red knot Calidris canutus, fed natural and artificial prey types under naturalistic but fully controlled indoor aviary conditions. During eight 1-day trials we successfully manipulated the extent to which the five red knots were (1) actively probing and walking (i.e. foraging) and (2)actually ingesting prey (i.e. processing food) that was (3) either hard-shelled or not (i.e. crushing). Energy expenditures, estimated by the doubly labelled water (DLW) method, calibrated for use in this particular condition, varied between 1.5 and 4 W. A hierarchical analysis of variance indicated that the crushing of hard-shelled prey entailed no extra cost. We arrived at the following breakdown of cost components under the thermoneutral conditions of the experiment: a cost of active rest/maintenance of 1.665 W, an additional cost of foraging of 0.602 W and an additional digestive processing cost of 1.082 W. These cost levels are all well within the range of expectation and are consistent with the results of a separate outdoor aviary experiment in which the thermostatic costs needed separate estimation. On the basis of the cost and performance functions of gizzards of different mass, it was shown that under the conditions of this experiment the red knots expended the bare minimum for a balanced budget, maintaining the smallest possible gizzard. Under field conditions a larger gizzard would be required.
Cost-benefit analysis of mollusc-eating in a shorebird II. Optimizing gizzard size in the face of seasonal demands
Authors: van Gils Jan A. , Piersma Theunis , Dekinga Anne , Dietz Maurine W.
Published: August 2003

Aiming to interpret functionally the large variation in gizzard masses of red knots Calidris canutus, we experimentally studied how the digestive processing rate is influenced by the size of the gizzard. During their non-breeding season, red knots feed on hard-shelled molluscs, which they ingest whole and crush in their gizzard. In three experiments with captive birds we tested predictions of the hypothesis that gizzard size, viathe rate of shell crushing and processing, constrains intake rate in red knots(against the alternative idea that external handling times constrain intake rate). Gizzard size within individual birds was manipulated by varying the hardness of the diet on offer, and was confirmed by ultrasonography. The results upheld the `shell-crushing hypothesis' and rejected the `handling time hypothesis'. Intake rates on with-shell prey increased with gizzard size, and decreased with shell mass per prey. Intake rates on soft (without shell) prey were higher than on with-shell prey and were unaffected by gizzard size. Offering prey that were heavily shelled relative to their flesh mass led to energy intake rates that were marginally sufficient to balance the daily energy budget within the time that is naturally available in a tidal system. We predicted the optimal gizzard sizes that are required to either (1) balance energy income with energy expenditure, or (2) to maximise net daily energy intake. The gizzard mass of free-living red knots in the Wadden Sea is such that it maximises daily net energy intake in spring when fuelling for migration, while it balances energy budget throughout the remainder of the year.
Interindividual variation of eye optics and single object resolution in bumblebees
Authors: Spaethe Johannes , Chittka Lars
Published: August 2003

In the eusocial bumblebees, distinct size variation occurs within the worker caste of a colony. We show that there are pronounced differences in compound eye optical quality between individual workers in Bombus terrestris. Using scanning electron microscopy and antidromic illumination techniques (the pseudopupil method), we demonstrate that large workers have extended facet diameters in conjunction with reduced interommatidial angles. Thus, both overall sensitivity and image resolution are superior in such individuals. Behavioural tests show that a 33% increase in body size is accompanied by 100% greater precision in single target detection. This improvement in spatial resolving power is much stronger than that predicted by surveying ommatidial arrays, indicating that measuring eye optics alone is insufficient for predictions of single object resolution,unless combined with behavioural tests. We demonstrate that in small bees the minimum number of ommatidia involved in target detection is seven, while in large workers a single ommatidium is sufficient for target detection. These findings have implications for foraging and division of labour in social insects.
The retina ofManduca sexta: rhodopsin expression, the mosaic of green-, blue- and UV-sensitive photoreceptors, and regional specialization
Authors: White Richard H. , Xu Huihong , Münch Thomas A. , Bennett Ruth R. , Grable Erin A.
Published: August 2003

Spectral sensitivities of individual photoreceptors in the compound eye of Manduca sexta were verified by immunocytochemistry, and the retinal mosaic was mapped, using polyclonal antisera raised against amino-terminal sequences of three identified rhodopsins: P520, P450 and P357. Retinulae are composed of a small proximal cell and seven or eight elongate cells extending across the retina. In each retinula, one or two elongate dv cells oriented in the dorsal-ventral axis of the retinal lattice express either P450 or P357. Six elongate ap and ob cells in the anterior-posterior and oblique axes express P520. The small proximal pr cell also appears to express P520. The retinal mosaic is regionalized into three distinct domains: ventral and dorsal domains that divide the main retina, and a large dorsal rim area. The immunocytochemical data provide a high-resolution map of the Manduca retina that confirms and refines earlier low-resolution ERG spectral sensitivity measurements. The dorsal and ventral domains, separated at a well-defined equatorial border, are distinguished by differences in the proportion of blue-sensitive dv cells: these cells dominate the ventral retina but are less abundant in the dorsal retina. Green-sensitive ap and ob receptors are uniformly distributed across the dorsal and ventral domains, and UV-sensitive dv cells are fairly uniformly distributed because many retinulae in the dorsal domain contain only one dv cell. Similarly, dorsal rim retinulae contain only the ventral member of the dv pair of receptors, two-thirds of which express P357. Otherwise,dorsal rim receptors express none of the three sequenced Manducaopsins; they must express rhodopsins that have yet to be cloned.
The integration of energy and nitrogen balance in the hummingbirdSephanoides sephaniodes
Authors: López-Calleja M. Victoria , Fernández María José , Bozinovic Francisco
Published: August 2003

Floral nectars are rich in energy but contain only traces of amino acids,and it has been hypothesized that arthropods may be an important source of energy and amino acids for hummingbirds. We studied the nitrogen requirements of hummingbirds as well as how they use small arthropods to satisfy their nitrogen and energy requirements and how organ mass varies with nitrogen intake. Non-reproductive green-backed firecrowns Sephanoides sephaniodes were maintained for 10 days on diets containing 0%, 0.96%,1.82%, 4.11% and 11.1% nitrogen (dry-matter basis). A second group of individuals were fed with varying amounts of nitrogen-free nectar supplemented with fruit flies. Finally, non-reproductive hummingbirds were captured as a control group for analysis of organ mass and size as well as fat content.

The maintenance nitrogen requirement of green-backed firecrowns determined by regression was 1.42 mg N day-1, yet they required nearly 10 mg N day-1 to maintain body mass. When arthropods were available, we observed that hummingbirds required approximately 150 fruit flies to maintain body mass, which corresponds to a 5% nitrogen diet. Interestingly, when nectar was restricted (to 4 ml day-1), or was absent, arthropods alone were not able to satisfy the body mass balance requirements of hummingbirds,suggesting that arthropods are not adequate as an energy source. In the group offered an 11.1% nitrogen diet, the size and surface of the small intestine,and liver and kidney mass increased in comparison with the control group(non-reproductive field hummingbirds) or the nitrogen-free group, suggesting a nitrogen overload. Our results are in agreement with other studies showing low nitrogen requirements by nectarivores. An important point to stress is that nitrogen digestibility declined in the 11.1% nitrogen diet, which strongly supports our nitrogen absorption saturation hypothesis.
Form and function of the bulbus arteriosus in yellowfin tuna (Thunnus albacares): dynamic properties
Authors: Braun Marvin H. , Brill Richard W. , Gosline John M. , Jones David R.
Published: August 2003

The bulbus arteriosus of the teleost heart possesses a static inflation curve that is r-shaped over the in vivo pressure range. To examine the possible significance of this in living animals, we recorded arterial blood pressure from anaesthetized yellowfin tuna and utilized a video dimensional analyser to simultaneously record changes in bulbar diameter. By plotting the changes in pressure against the changes in diameter, it was possible to create dynamic pressure-diameter (P-D) loops as well as calculate the instantaneous volume changes within the bulbus. The dynamic P-D loops showed the same features exhibited by static inflation. When nearly empty, a small stroke volume caused a large increase in blood pressure, while around systolic pressure large changes in volume resulted in small changes in pressure. We conclude that these features allow the bulbus to maintain ventral aortic flows and pressures over a large range of volumes.