Thermal conductivity vs depth profiling using the hot disk technique-Analysis of anisotropic, inhomogeneous structures

A recently developed method for analyzing the thermal conductivity vs depth variation near a sample surface has been extended to include inhomogeneous samples with anisotropy. If not considered, the anisotropy ratio in the sample structure can distort the depth-position data of the original test method. The anisotropy ratio is introduced in the original computational scheme in order to improve the depth-position estimations for inhomogeneous structures with anisotropy. The proposed approach has been tested in experiments and shown to improve depth position mapping.

Risk assessment of chemicals and their mixtures are hindered by scarcity and inconsistencies between different environmental exposure limits

In chemical risk assessment, measured or modelled environmental concentrations are compared to environmental exposure limits (EELs), such as Predicted No Effect Concentrations (PNECs) or hazardous concentrations for 5% of species (HC05s) derived from species sensitivity distributions (SSDs). However, for many chemicals the EELs include large uncertainties or, in the worst case, the necessary data for their estimation are completely missing. This makes the assessment of chemical risks and any subsequent implementation of management strategies challenging. In this study we analyzed the uncertainty of EELs and its impact on chemical risk assessment. First, we compared three individual EEL datasets, two primarily based on experimental data and one based on computational predictions. The comparison demonstrates large disagreements between EEL data sources, with experimentally derived EELs differing by more than seven orders of magnitude. In a case-study, based on the predicted emissions of 2005 chemicals, we showed that these uncertainties lead to significantly different risk assessment outcomes, including large differences in the magnitude of the total risk, risk driver identification, and the ranking of use categories as risk contributors. We also show that the large data-gaps in EEL datasets cannot be covered by commonly used computational approaches (QSARs). We conclude that an expanded framework for interpreting risk characterization outcomes is needed. We also argue that the large data-gaps present in ecotoxicological data need to be addressed in order to achieve the European zero pollution vision as the growing emphasis on ambient exposures will further increase the demand for accurate and well-established EELs.

Estimating the release of chemical substances from consumer products, textiles and pharmaceuticals to wastewater

Chemical emissions from households originate from a wide range of sources and results in highly diverse mixtures. This makes traditional monitoring based on analytical chemistry challenging, especially for compounds that appear in low concentrations. We therefore developed a method for predicting emissions of chemicals from households into wastewater, relying on consumption patterns from multiple data sources. The method was then used to predict the emissions of chemical preparations, chemicals leaching from textiles and prescription pharmaceuticals in Sweden. In total we predicted emissions of 2007 chemicals with a combined emission of 62,659 tonnes per year - or 18 g/person and day. Of the emitted chemicals, 2.0% (w/w) were either classified as hazardous to the environment or were both persistent and mobile. We also show that chemical emissions come from a wide range of uses and that the total emission of any individual chemical is determined primarily by its use pattern, not by the total amount used. This emphasizes the need for continuous updates and additional knowledge generation both on emission factors and excretion rates as well as a need for improved reporting on the intended use of individual chemicals. Finally, we scrutinize the model and its uncertainty and suggest areas that need improvement to increase the accuracy of future emission modelling. We conclude that emission modelling can help guide environmental monitoring and provide input into management strategies aimed at reducing the environmental effect caused by hazardous chemicals.

The role of brokers in a workplace development programme targeting SMEs

Purpose

The purpose of this paper is to investigate the development of a workplace development programme (WPDP) targeting small and medium sized manufacturing enterprises (SMEs) by focussing on the people who acted as brokers providing cross-boundary connections between its collaborating partners.

Design/methodology/approach

The material, from interviews with 32 individuals and 11 meetings, was analysed in a boundary-crossing framework, which provided tools to reveal how the roles of brokers at different levels (operative, strategic and national) of the WPDP affected its development.

Findings

The findings indicate that cross-boundary connections were made by persons who acted as brokers within and between different levels of the WPDP. The brokers who provided cross-boundary connections between different levels of the WPDP were found to play the most important role for the prompt development of the WPDP.

Originality/value

Apart from unique empirical material depicting the development of a collaborative venture between national and regional stakeholders of the manufacturing industry, the value of this study is the attention given to the people behind the policymaking of publicly funded national WPDPs, revealing the complex business of developing policy-driven competence development activities to employees in SMEs.

Introducing Motivational Interviewing in a Sickness Insurance Context: Translation and Implementation Challenges

Purpose Motivational interviewing (MI) is a conversational method to support clients in need of behavioral change. In an organizational reform, most Swedish sickness insurance officials were trained in MI to promote clients' return to work (RTW) after sick leave. The aim of this article is to investigate experiences of introducing MI as a tool to promote clients' RTW within a sickness insurance context, with special focus on the translation and implementation of the method. Methods A qualitative approach, comprising 69 interviews with officials, managers, and regional coordinators on two occasions. The material was analyzed through qualitative content analysis. Results Officials were positive about MI, but the application was limited to using certain tools with extensive individual variation. Officials struggled with translating MI into a sickness insurance context, where the implementation strategy largely failed to offer adequate support, due to low managerial priority, competing initiatives, and a high workload. Results of the educational intervention could therefore be seen on an individual but not an organizational level. Conclusions In order to translate MI into a sickness insurance context, training needs to be supported by organizational approaches that promote collective learning and sharing of experiences among officials. The results also illustrate how a method cannot be assumed to be implemented simply because training has been provided. Consequently, the application of the method needs to be carefully monitored in studies of interventions where MI is claimed to be used, in order to measure its effectiveness.

Thermal conductivity versus depth profiling of inhomogeneous materials using the hot disc technique

Transient measurements of thermal conductivity are performed with hot disc sensors on samples having a thermal conductivity variation adjacent to the sample surface. A modified computational approach is introduced, which provides a method of connecting the time-variable to a corresponding depth-position. This allows highly approximate-yet reproducible-estimations of the thermal conductivity vs. depth. Tests are made on samples incorporating different degrees of sharp structural defects at a certain depth position inside a sample. The proposed methodology opens up new possibilities to perform non-destructive testing; for instance, verifying thermal conductivity homogeneity in a sample, or estimating the thickness of a deviating zone near the sample surface (such as a skin tumor), or testing for presence of other defects.

Lean production tools and decision latitude enable conditions for innovative learning in organizations: a multilevel analysis

The effect of lean production on conditions for learning is debated. This study aimed to investigate how tools inspired by lean production (standardization, resource reduction, visual monitoring, housekeeping, value flow analysis) were associated with an innovative learning climate and with collective dispersion of ideas in organizations, and whether decision latitude contributed to these associations. A questionnaire was sent out to employees in public, private, production and service organizations (n = 4442). Multilevel linear regression analyses were used. Use of lean tools and decision latitude were positively associated with an innovative learning climate and collective dispersion of ideas. A low degree of decision latitude was a modifier in the association to collective dispersion of ideas. Lean tools can enable shared understanding and collective spreading of ideas, needed for the development of work processes, especially when decision latitude is low. Value flow analysis played a pivotal role in the associations.

Pulse transient hot strip technique adapted for slab sample geometry to study anisotropic thermal transport properties of μm-thin crystalline films

A new method based on the adaptation of the Pulse Transient Hot Strip technique to slab sample geometry has been developed for studying thermal conductivity and thermal diffusivity of anisotropic thin film materials (<50 μm) with thermal conductivity in the 0.01-100 W/mK range, deposited on thin substrates (i.e., wafers). Strength of this technique is that it provides a well-controlled thermal probing depth, making it possible to probe a predetermined depth of the sample layer and thereby avoiding the influence from material(s) deeper down in the sample. To verify the technique a series of measurements were conducted on a y-cut single crystal quartz wafer. A Hot Strip sensor (32-μm wide, 3.2-mm long) was deposited along two orthogonal crystallographic (x- and z-) directions and two independent pulse transients were recorded. Thereafter, the data was fitted to our theoretical model, and the anisotropic thermal transport properties were determined. Using a thermal probing depth of only 30 μm, we obtained a thermal conductivity along the perpendicular (parallel) direction to the z-, i.e., optic axis of 6.48 (11.4) W/mK, and a thermal diffusivity of 3.62 (6.52) mm(2)/s. This yields a volumetric specific heat of 1.79 MJ/mK. These values agree well with tabulated data on bulk crystalline quartz supporting the accuracy of the technique, and the obtained standard deviation of less than 2.7% demonstrates the precision of this new measurement technique.

The importance of work conditions and health for voluntary job mobility: a two-year follow-up

Background

Changing jobs is part of modern working life. Within occupational health, job mobility has mainly been studied in terms of employees’ intentions to leave their jobs. In contrast to actual turnover, turnover intentions are not definite and only reflect the probability that an individual will change job. The aim of this study was to determine what work conditions predict voluntary job mobility and to examine if good health or burnout predicts voluntary job mobility.

Methods

The study was based on questionnaire data from 792 civil servants. The data were analysed using logistic regressions.

Results

Low variety and high autonomy were associated with increased voluntary job mobility. However, the associations between health and voluntary job mobility did not reach significance. Possible explanations for the null results may be that the population was homogeneous, and that the instruments for measuring global health are too coarse for a healthy, working population.

Conclusions

Voluntary job mobility may be predicted by high autonomy and low variety. The former may reflect that individuals with high autonomy have stronger career development motives; the latter may reflect the fact that low variety leads to job dissatisfaction. In contrast to our results on job content, global health measurements are not strong predictors of voluntary job mobility. This may be because good health affects job mobility through several offsetting channels, involving the resources and ability to seek a new job. Future work should use more detailed measurements of health or examine other work settings so that we may learn more about which of the offsetting effects of health dominate in different contexts.

Progression from mild to pronounced MCI is not associated with cerebrospinal fluid biomarker deviations

BACKGROUND/AIM

Detection of cerebrospinal fluid (CSF) biomarker deviations improve prediction of progression from mild cognitive impairment (MCI) to dementia. However, it is not settled whether the same pattern exists in patients progressing from very mild to more pronounced MCI. Given that neurodegenerative processes occur very early in the disease course, we also expected to find biomarker deviations in these patients.

METHODS

A total of 246 memory clinic patients with non-progressive (n = 161), progressive (n = 19), or converting (n = 66) MCI, 67 with stable dementia, and 80 controls were followed for 24 months. At baseline, CSF total tau (T-tau), β-amyloid 1-42 (Aβ42) and the light subunit of neurofilament protein (NFL) were determined.

RESULTS

Patients with converting MCI and stable dementia had lower CSF Aβ42 concentrations and higher T-tau concentrations and NFL in comparison with controls and non-progressive/progressive MCI (p < 0.0005). No differences were found between progressive and non-progressive MCI.

CONCLUSION

As expected, biomarker deviations predicted progression from MCI to dementia. Contrary to our hypothesis, progression from very mild MCI to more pronounced MCI was not reflected by biomarker deviations. The results suggest that the measured biomarkers are not early disease markers, or alternatively Alzheimer or vascular pathology is not the underlying cause in this patient group.

New ways of organizing product introductions

The aim of this paper is to describe and reflect on an interactive research approach used to address the challenges on how to improve product introductions, the part of the product realization process associated with the transfer of a product from product development to serial production. In the interactive research approach, research results as well as improvement of practice are given equal importance. The collaboration between researchers and practitioners therefore addresses both the focus and the process of the change. The approach includes four main iterative steps: 1) mapping/diagnosis, 2) feedback of results, 3) participation in development activities, and 4) follow-up/evaluation. The paper reports findings from interactive research in one company within office product industry and one company group, consisting of three company units within the engine industry. Preliminary findings indicate that the participating companies afterwards work in a more structured way with product introductions and that the employees have gained deeper knowledge about product introductions as well as experienced the advantages of working across functional boundaries. Furthermore, the interactive research approach is suitable to run projects from an ergonomics perspective as it focuses on developing both practice and theory, it is human-centered, and it emphasizes broad participation from practitioners.

Evaluation of job stress models for predicting health at work

OBJECTIVES

Few workplace health promotion (WHP) interventions are designed to improve work conditions. Methods for measurement of work conditions are often developed from a risk factor perspective rather than a WHP perspective. More knowledge is needed on the work conditions that promote health in order to develop a good work environment. The purpose of the present study was to investigate if the Demand Control Support model, the Effort Reward Imbalance model and the Job Characteristic Inventory are correlated, if the subscales predict health and to analyze which combination of subscales is the most useful predictor of health longitudinally.

PARTICIPANTS

The study used questionnaire data from 662 civil servants at baseline and at follow-up 2 years later.

METHOD

The data were analysed by multiple regressions.

RESULTS

A new model; effort, reward, and variety, was found having a higher predictive power to predict health than the original models.

CONCLUSIONS

To promote health at work, social relations and health-mediating work conditions are important because these conditions may buffer health. Health can be assumed to be a resource that is created in everyday activities and interactions in workplaces, and there is a need to develop health measure instruments based on holistic health theories.

Swedish students' and preceptors' perceptions of what students learn in a six-month advanced pharmacy practice experience

OBJECTIVE

To identify what pharmacy students learn during the 6-month advanced pharmacy practice experience (APPE) in Sweden.

METHODS

Semi-structured interviews were conducted with 18 pharmacy APPE students and 17 pharmacist preceptors and analyzed in a qualitative directed content analysis using a defined workplace learning typology for categories.

RESULTS

The Swedish APPE provides students with task performance skills for work at pharmacies and social and professional knowledge, such as teamwork, how to learn while in a work setting, self-evaluation, understanding of the pharmacist role, and decision making and problem solving skills. Many of these skills and knowledge are not accounted for in the curricula in Sweden. Using a workplace learning typology to identify learning outcomes, as in this study, could be useful for curricula development.

CONCLUSIONS

Exploring the learning that takes place during the APPE in a pharmacy revealed a broad range of skills and knowledge that students acquire.

Circling around in tiredness: perspectives of patients on peritoneal dialysis

The experience of tiredness linked to poor sleep in patients on peritoneal dialysis was explored using the qualitative method phenomenology. Eight women and six men in southeast Sweden were interviewed. The patients' descriptions were characterized by a circular structure "circling around in tiredness." This study illustrates the problems of tiredness and illuminates the need for healthcare professionals to assess the impact of tiredness and highlight the need for strategies to improve the patient's situation.

Factors associated with reflection among students after an advanced pharmacy practice experience (APPE) in Sweden

OBJECTIVE

To identify individual and social factors associated with pharmacy students' level of reflection in an advanced pharmacy practice experience (APPE).

METHODS

A postal questionnaire, including a reflective assignment, was sent to all pharmacy interns (n=262) at Uppsala University, Sweden, for 4 semesters in 2005-2007.

RESULTS

In a univariate analysis, 7 factors were found to be associated with students' level of reflection. After controlling for covariates, 3 social factors were found to be independently associated with reflection: having a formal preceptor (OR=5.3), being at a small pharmacy (OR=19.8), and students' perception of the importance of discussing critical thinking with the preceptor (OR=1.2). No correlation could be observed between level of reflection and critical thinking, nor learning style.

CONCLUSION

Social components seem to be of higher importance than individual components in students' reflective levels after pharmacy internship experience. Trained preceptors are important to foster reflection skills.

Effect of tube current on diagnostic image quality in paediatric cerebral multidetector CT images

The aim of this study was to investigate the effect of tube current on diagnostic image quality in paediatric cerebral multidetector CT (MDCT) images in order to identify the minimum radiation dose required to reproduce acceptable levels of different diagnostic image qualities. Original digital scanning data (raw data) were selected retrospectively from routine MDCT brain examinations of 25 paediatric patients. All examinations had been performed using axial scanning on an eight-slice MDCT (LightSpeed Ultra, GE Healthcare). Their ages ranged from newborn to 15 years. Quantum noise was added artificially to the raw data representing dose reductions equivalent to steps of 20 mA. Patient identification information was removed. Three experienced radiologists blindly and randomly assessed the resulting images from two different levels of the brain with regard to reproduction of structures and overall image quality. Final data were evaluated using the non-parametric statistical approach of inter-scale concordance. The minimum value of tube current-time product (mAs) required to reproduce an image of sufficient diagnostic quality was established in relation to the age of the patient. The corresponding CT dose index values by volume (CTDI(vol) (mGy)) were also established. In conclusion, acceptable reproduction of low-contrast structures was possible at CTDI(vol) values down to 20 mGy (patients 1-5 years old). For acceptable reproduction of high-contrast structures, CTDI(vol) values down to 10 mGy were considered possible (patients 1-5 years old). The original image quality for patients under 6 months of age (15 mGy) was found to be inadequate for acceptable reproduction of low-contrast structures.

Control of interaction-induced dephasing of Bloch oscillations

We report on the control of interaction-induced dephasing of Bloch oscillations for an atomic Bose-Einstein condensate in an optical lattice. We quantify the dephasing in terms of the width of the quasimomentum distribution and measure its dependence on time for different interaction strengths which we control by means of a Feshbach resonance. For minimal interaction, the dephasing time is increased from a few to more than 20 thousand Bloch oscillation periods, allowing us to realize a BEC-based atom interferometer in the noninteracting limit.

A method of predicting the image noise in paediatric multi-slice computed tomography images

The purpose of this study was to develop an equation with which to determine the tube current to be used in order to obtain a certain image noise level for differently sized children undergoing multi-slice computed tomography examination. The relationship between image noise and detector dose for different examination protocols was established for a LightSpeed Ultra, an eight slice CT from GEMS, using homogeneous water phantoms of different sizes. Three different anatomical areas (head, thorax and abdomen) were studied in 111 patients between 0 and 17 y of age. The mean ratio between the calculated and the measured noise in patient images was established for the different areas. Head examinations showed the best correlation (measured-to-calculated noise ratio = 1.01). In the thorax, the calculated noise was generally higher than the measured noise (ratio = 0.74), and in the abdomen, the opposite result was found (ratio = 1.20).

Stable linker peptides for a cellulose-binding domain-lipase fusion protein expressed in Pichia pastoris

Fusion proteins composed of a cellulose-binding domain from Neocallimastix patriciarum cellulase A and Candida antarctica lipase B were constructed using different linker peptides. The aim was to create proteolytically stable linkers that were able to join the functional modules without disrupting their function. Six fusion variants containing linkers of 4-44 residues were expressed in Pichia pastoris and analysed. Three variants were found to be stable throughout 7-day cultivations. The cellulose-binding capacities of fusion proteins containing short linkers were slightly lower compared with those containing long linkers. The lipase-specific activities of all variants, in solution or immobilized on to cellulose, were equal to that of the wild-type lipase.

Expression in Pichia pastoris of Candida antarctica lipase B and lipase B fused to a cellulose-binding domain

Candida antarctica lipase B (CALB) and C. antarctica lipase B fused to a cellulose-binding domain (CBD-CALB) were expressed functionally in the methylotrophic yeast Pichia pastoris. The cellulose-binding domain originates from cellulase A of the anaerobic rumen fungus Neocallimastix patriciarum. The genes were fused to the alpha-factor secretion signal sequence of Saccharomyces cerevisiae and placed under the control of the alcohol oxidase gene (AOX1) promoter. The recombinant proteins were secreted into the culture medium reaching levels of approximately 25 mg/L. The proteins were purified using hydrophobic interaction chromatography and gel filtration with an overall yield of 69%. Results from endoglycosidase H digestion of the proteins showed that CALB and CBD-CALB were N-glycosylated. The specific hydrolytic activities of recombinant CALB and CBD-CALB were identical to that reported for CALB isolated from its native source. The fusion of the CBD to the lipase resulted in a greatly enhanced binding toward cellulose for CBD-CALB compared with that for CALB.

ELF magnetic fields in a city environment

Some epidemiological studies indicate an association between extremely low frequency electromagnetic field (ELF-EMF) exposure and cancer risks. These studies have mainly taken residential and occupational exposure into consideration. Outdoor environments are often considered as low level areas, but in this paper we show that this is not true in a city environment. We have mapped the ELF magnetic flux densities along certain stretches of sidewalk in central Göteborg City, Sweden. About 50% of the investigated street length shows flux densities of the same order of magnitude (0.2 microT and above) as those associated with increased risks of cancer in epidemiological studies. We conclude that the outdoor exposures in a city environment also should be considered in exposure assessments and risk evaluations. These elevated flux densities are probably due to stray currents. We also found strong magnetic flux densities (> 1.0 microT) close to ordinary distribution pillars, power substations, shoplifting alarms, and other electrical devices.

An acyl-CoA:cholesterol acyltransferase (ACAT)-related gene is involved in the accumulation of triacylglycerols in Saccharomyces cerevisiae

The major route for the synthesis of triacylglycerol (TAG) in yeast as well as in all TAG-accumulating organisms has been suggested to occur via the acylation of diacylglycerol (DAG) by acyl-CoA:diacylglycerol acyltransferase (DAGAT). Genes encoding DAGAT have been identified in both plant and animal tissues. These genes show strong sequence similarities to genes encoding acyl-CoA:cholesterol acyltransferase (ACAT). So far no Saccharomyces cerevisiae DAGAT gene has been published; however, two ACAT-like genes, ARE1 and ARE2, are present in the yeast genome. Both these genes have been suggested to be involved in the synthesis of sterol esters. We have now shown that the ARE1 gene in yeast also is involved in the synthesis of TAG, whereas the ARE2 gene is more specifically involved in the synthesis of sterol esters.

Linkage analysis of candidate regions in Swedish nonsyndromic cleft lip with or without cleft palate families

OBJECTIVE

To analyze linkage of five candidate regions for nonsyndromic cleft lip with or without palate (CLP) on chromosome 2p13, 4q, 6p23, and 19q13; in addition chromosome 1q32, the locus for van der Woude syndrome, on Swedish CLP families.

DESIGN

Three to five linked microsatellite markers were selected from each candidate region. Polymerase chain reaction (PCR) with fluorescent-labeled microsatellite markers was performed on DNA samples from the participating families. Electrophoresis of the PCR products was performed on a laser-fluorescent DNA sequencer. The genotype data were analyzed with multipoint linkage analysis. Modes of inheritance tested included two autosomal dominant, an autosomal recessive, and a nonparametric model. Multipoint logarithm of odds (LOD) scores were also calculated by assuming genetic heterogeneity.

PARTICIPANTS

Nineteen Swedish multigenerational families with at least two first-degree relatives affected with CLP. Greater than 50% of the families studied show vertical transmission of the clefting phenotype and both inter- and intrafamilial variability were noted.

RESULTS

Cumulative multipoint LOD scores for the whole group of families calculated under autosomal dominant modes of inheritance were negative in all regions and less than -2 except chromosome 6p23. LOD scores calculated under recessive inheritance and the nonparametric model were inconclusive. There was no significant evidence of genetic heterogeneity among the sample group.

CONCLUSIONS

The group of Swedish CLP families did not demonstrate significant linkage to any of the five candidate regions examined. This might suggest a new but yet unknown CLP locus or loci in this family group. However, because linkage could not be excluded in some individual families, they should still be tested with candidate genes from these regions.

[Evaluation of the law of communicable disease control: compulsory isolation can reduce the high-risk behavior of HIV-positive individuals]

The Swedish approach to HIV is based on HIV-positive individuals' fulfilling their societal obligation to prevent further spread of the disease. Under section 38 of the Communicable Disease Act of 1989, compulsory admission to hospital may be resorted to in cases where voluntary efforts have failed to bring about modification of high-risk behaviour. The article consists in a report of a retrospective study of the effects of such enforced isolation in the HIV-positive subgroup committed under the Act within an eight-year period. Relevant information was obtained from the records of medical and psychiatric hospitals, the social services and correctional care authorities. Modification of high-risk behaviour was assessed by enquiries involving attending physicians, the social services, and prison and police authorities, and by interviews with the patients. During the 8-year period, 1.5 per cent (44/2982) of registered HIV-positive patients in Stockholm County were committed by the county administrative court to compulsory admission. Of the 44 patients, 25 (57%) were born in Sweden, and 19 (43%) elsewhere (mostly sub-Saharan African countries where HIV is highly endemic). Intravenous drug abuse was very common in the subgroup, and 34 per cent of them were diagnosed as having a psychiatric disorder or intellectual handicap. Thirty-four (77%) of the subgroup were released after varying periods of isolation. Follow-up at 6, 18 and 36 months showed the overwhelming majority to be capable of maintaining a low-risk profile, and only 20 per cent to be characterised by continued high-risk behaviour (suspected or verified). The results thus suggest that individuals with the intellectual and psychiatric capacity to comprehend the serious nature of HIV infection and its modes of transmission can successfully modify risk behaviour by undergoing intensified individualised programmes, provided the duration of isolation is sufficiently long.

Liquid chromatography "on-flow" 1H nuclear magnetic resonance on native glycosphingolipid mixtures together with gas chromatography/mass spectrometry on the released oligosaccharides for screening and characterisation of carbohydrate-based antigens from pig lungs

Glycosphingolipids were prepared from pig lung and pooled into two fractions with (i) < or = 3 sugar residues, and (ii) > or = 3 sugar residues. Oligosaccharides were prepared and used for gas chromatography, gas chromatography/mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry. The glycolipid fractions i and ii were further characterised and purified using a novel method based on high performance liquid chromatography "on-flow" proton nuclear magnetic resonance. The LC "on-flow" NMR technique showed good chromatographic separation and gave NMR spectral information which could be used as guidance for pooling of the separated mixture glycolipids. Conventional 1H NMR, thin layer immunostaining, gas chromatography, gas chromatography/mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry were used to characterise the glycolipids and to validate LC-NMR spectral data.

Automated sample preparation for the determination of budesonide in plasma samples by liquid chromatography and tandem mass spectrometry

An automated bioanalytical method for the determination of the glucocorticosteroid drug budesonide in plasma samples at pM levels was investigated. The method was built using three separate automated analytical steps with manual transfer of samples between them. In the first step, a Tecan RSP150 (Genesis) pipetting robot was used to transfer 1 ml of centrifuged plasma samples and deuterated budesonide internal standard solutions into tubes and to homogenise the resulting admixture. In the second step, a solid-phase extraction was performed using an ASPEC Xli (Gilson) with 100 mg Isolute C18 columns. In order to avoid conventional time-consuming evaporation and reconstitution steps, the solid-phase extraction was coupled on-line to a trace enrichment system for further purification and concentration of the sample extracts. The concentrated samples were eluted in 300 microliters ethanol into injection vials, which were capped and transferred to the autosampler in the detection system. In the third step, the pre-treated samples were chromatographed in a gradient LC system and detected using a tandem MS system (Finnigan TSQ 7000), with an atmospheric pressure chemical ionisation interface. The described Analytical System consisting of one Tecan robot, two ASPEC systems and one LC-MS-MS system may analyse up to about 800 samples a week with less routine work for the analyst. The concentration range studied was 15 to 2500 pM in 1 ml spiked plasma samples and the limit of quantitation for the described method was determined as 15 pM, as defined by accuracy and precision better than 20%.

Phagosome-lysosome fusion is a calcium-independent event in macrophages

Phagosome-lysosome membrane fusion is a highly regulated event that is essential for intracellular killing of microorganisms. Functionally, it represents a form of polarized regulated secretion, which is classically dependent on increases in intracellular ionized calcium ([Ca2+]i). Indeed, increases in [Ca2+]i are essential for phagosome-granule (lysosome) fusion in neutrophils and for lysosomal fusion events that mediate host cell invasion by Trypanosoma cruzi trypomastigotes. Since several intracellular pathogens survive in macrophage phagosomes that do not fuse with lysosomes, we examined the regulation of phagosome-lysosome fusion in macrophages. Macrophages (M phi) were treated with 12.5 microM bis-(2-amino-S-methylphenoxy) ethane-N,N,N',N',-tetraacetic acid tetraacetoxymethyl ester (MAPT/AM), a cell-permeant calcium chelator which reduced resting cytoplasmic [Ca2+]; from 80 nM to < or = 20 nM and completely blocked increases in [Ca2+]i in response to multiple stimuli, even in the presence of extracellular calcium. Subsequently, M phi phagocytosed serum-opsonized zymosan, staphylococci, or Mycobacterium bovis. Microbes were enumerated by 4',6-diamidino-2-phenylindole, dihydrochloride (DAPI) staining, and phagosome-lysosome fusion was scored using both lysosome-associated membrane protein (LAMP-1) as a membrane marker and rhodamine dextran as a content marker for lysosomes. Confirmation of phagosome-lysosome fusion by electron microscopy validated the fluorescence microscopy findings. We found that phagosome-lysosome fusion in M phi occurs noramlly at very low [Ca2+]i (< or = 20 nM). Kinetic analysis showed that in M phi none of the steps leading from particle binding to eventual phagosome-lysosome fusion are regulated by [Ca2+]i in a rate-limiting way. Furthermore, confocal microscopy revealed no difference in the intensity of LAMP-1 immunofluorescence in phagolysosome membranes in calcium-buffered vs. control macrophages. We conclude that neither membrane recognition nor fusion events in the phagosomal pathway in macrophages are dependent on or regulated by calcium.