| 1. |
- Al-Emrani, Mohammad, 1967, et al.
(författare)
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Girders with Trapezoidally Corrugated Webs -- Under Patch Loading
- 2011
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Ingår i: EUROSTEEL 2011. - 9789291471034 ; 2, s. 620-625
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Konferensbidrag (refereegranskat)abstract
- This paper deals with the buckling and postbuckling behaviour of plate girders with corrugated web under a concentrated load on the top flange. A couple of design models and experiments from earlier studies are briefly reviewed.Further, six additional experimental tests have been performed on a girder with thin corrugated web. A FE-model of this girder is then developed and the behaviour of the girder is validated through comparisons with the girder used in the tests. The ultimate load and the postbuckling behaviour were determined by both laboratory tests and finite element simulations for three different positions of a narrow load strip across the flange, namely at: (1) an inclined fold, (2) the junction between two folds, (3) a longitudinal fold. Finally, a parametric study is performed using the FE-model where the influence of certain parameters on the ultimate load and buckling behaviour is investigated. The results from this parametric study are compared and evaluated together with two design models chosen to be the most suitable.
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| 2. |
- Alm, Erik, 1980-, et al.
(författare)
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Vibrational overtone combination spectroscopy (VOCSY)—a new way of using IR and NIR data
- 2007
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 388:1, s. 179-188
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Tidskriftsartikel (refereegranskat)abstract
- This work explores a novel method for rearranging 1st order (one-way) infra-red (IR) and/or near infra-red (NIR) ordinary spectra into a representation suitable for multi-way modelling and analysis. The method is based on the fact that the fundamental IR absorption and the first, second, and consecutive overtones of NIR absorptions represent identical chemical information. It is therefore possible to rearrange these overtone regions of the vectors comprising an IR and NIR spectrum into a matrix where the fundamental, 1st, 2nd, and consecutive overtones of the spectrum are arranged as either rows or columns in a matrix, resulting in a true three-way tensor of data for several samples. This tensorization facilitates explorative analysis and modelling with multi-way methods, for example parallel factor analysis (PARAFAC), N-way partial least squares (N-PLS), and Tucker models. The vibrational overtone combination spectroscopy (VOCSY) arrangement is shown to benefit from the “order advantage”, producing more robust, stable, and interpretable models than, for example, the traditional PLS modelling method. The proposed method also opens the field of NIR for true peak decomposition—a feature unique to the method because the latent factors acquired using PARAFAC can represent pure spectral components whereas latent factors in principal component analysis (PCA) and PLS usually do not.
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| 3. |
- Andersch-Björkman, Ylva, et al.
(författare)
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Air-oxidized linalool elicits eczema in allergic patients-a repeated open application test study.
- 2014
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Ingår i: Contact dermatitis. - : Wiley. - 1600-0536 .- 0105-1873. ; 70:3, s. 129-38
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Tidskriftsartikel (refereegranskat)abstract
- Linalool is a commonly used fragrance terpene that forms potent sensitizers upon oxidation. In a recent multicentre study, we found that 7% of 2900 patients showed positive patch test reactions to oxidized linalool at 6.0%. No elicitation studies have been performed.
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| 4. |
- Bodén, Ida, 1977-
(författare)
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Near infrared and skin impedance spectroscopic in vivo measurements on human skin : development of a diagnostic tool for skin cancer
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Every year approximately 2800 Swedes are diagnosed with malignant melanoma, the form of cancer that is most rapidly increasing in incidence in the Western world. The earlier we can identify and diagnose a malignant melanoma, the better is the prognosis. In Sweden, 155 000 benign naevi, harmless skin tumours or moles, are surgically excised each year, many of them because melanoma cannot be dismissed by non-invasive methods. The excisions result in substantial medical costs and cause unrest and suffering of the individual patient. For untrained physicians, it is often difficult to make an accurate diagnosis of melanoma, thus a tool that could help to strengthen the diagnosis of suspected melanomas would be highly valuable. This thesis describes the development and assessment of a non-invasive method for early skin cancer detection. Using near infrared (NIR) and skin impedance spectroscopy, healthy and diseased skin of various subjects was examined to develop a new instrument for detecting malignant melanoma. Due to the complex nature of skin and the numerous variables involved, the spectroscopic data were analysed multivariately using Principal Component Analysis (PCA) and partial leas square discriminant analysis (PLS-DA). The reproducibility of the measurements was determined by calculating Scatter Values (SVs), and the significance of separations between overlapping groups in score plots was determined by calculating intra-model distances. The studies indicate that combining skin impedance and NIR spectroscopy measurements adds value, therefore a new probe-head for simultaneous NIR and skin impedance measurements was introduced. Using both spectroscopic techniques it was possible to separate healthy skin at one body location from healthy skin at another location due to the differences in skin characteristics at various body locations. In addition, statistically significant differences between overlapping groups of both age and gender in score plots were detected. However, the differences in skin characteristics at different body locations had stronger effects on the measurements than both age and gender. Intake of coffee and alcohol prior to measurement did not significantly influence the outcome data. Measurements on dysplastic naevi were significantly separated in a score plot and the influence of diseased skin was stronger than that of body location. This was confirmed in a study where measurements were performed on 12 malignant melanomas, 19 dysplastic naevi and 19 benign naevi. The malignant melanomas were significantly separated from both dysplastic naevi and benign naevi. Overall, the presented findings show that the instrument we have developed provides fast, reproducible measurements, capable of distinguishing malignant melanoma from dysplastic naevi and benign naevi non-invasively with 83% sensitivity and 95% specificity. Thus, the results are highly promising and the instrument appears to have high potential diagnostic utility.
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| 5. |
- Claeson Bohnstedt, Kristina, 1974-
(författare)
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Determination of biomarkers for lipid peroxidation and oxidative stress : Development of analytical techniques and methods
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oxidative stress can be defined as a state of disturbance in the pro-oxidant/antioxidant balance in favour of the former, leading to potential damage. Processes associated with oxidative stress involve reactive oxygen species and radicals and can result in elevated levels of oxidatively modified or toxic molecules that can cause cellular malfunction, and even cell death. Destruction of membrane lipids, lipid peroxidation, caused by reactive oxygen species and radicals has been coupled to many diseases and also normal ageing. The measurement of low molecular weight biomarkers of oxidative stress present in complex matrices such as brain tissue, plasma, urine or cerebrospinal fluid is a delicate and difficult task and there is a need for improved analytical tools in this field of research. The major foci of this thesis and the work underlying it are the development of analytical techniques and methods for determining biomarkers for oxidative stress and lipid peroxidation. Aspects of particular concern include the effects of sample treatments prior to analysis, evaluation of the developed methods with respect to possible artefacts, and the scope for results to be misinterpreted. The specific research goals and issues addressed are detailed in five papers, which this thesis is based upon.Paper I focuses on malondialdehyde, describing and evaluating two new simplified sample pre-treatment regimes for the determination of malondialdehyde in rat brain tissue by capillary electrophoresis with UV detection. The effects of sample storing and handling are also considered.Paper II describes the synthesis, characterization and implementation of a new internal standard for the determination of malondialdehyde in biological samples using electrophoretic or chromatographic separation techniques. The usefulness of the internal standard is demonstrated in analyses of rat brain tissue samples.Paper III presents a method for the determination of 4-hydroxynon-2-enal in brain tissue from rats employing micellar electrokinetic chromatography separation and laser-induced fluorescence detection. Paper IV is focused on the development of a new methodology for determining the stereoisomeric F2-isoprostanes in human urine samples employing chromatographic separation on porous graphitic carbon and detection by electrospray ionization-tandem mass spectrometry. The results from this study conflict with the hypothesis that peripheral isoprostanes are elevated in patients with Alzheimer’s disease.Paper V describes porous graphitic carbon chromatography-tandem mass spectrometry for the determination of isoprostanes in human cerebrospinal fluid. A new simplified sample pre-treatment regime, involving a column switching technique, is presented that allows direct injection of a relatively large volume of CSF into the chromatographic system.
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| 6. |
- Claeson Bohnstedt, Kristina, et al.
(författare)
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Porous graphitic carbon chromatography-tandem mass spectrometry for the detection of isoprostanes in human cerebrospinal fluid
- 2005
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 827:1, s. 39-43
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Tidskriftsartikel (refereegranskat)abstract
- F2-isoprostanes are produced by the non-enzymatic peroxidation of arachidonic acid in membrane phospholipids. This paper describes a new method for the determination of all four classes of F2-isoprostanes in human cerebrospinal fluid (CSF) involving separation on a 1 mm × 150 mm porous graphitic carbon (PGC) column and detection by triple quadrupole mass spectrometry in negative-ion electrospray mode. The sample pre-treatment consisted of an ultrafiltration step, following which 300 μl of CSF sample could be injected directly onto a 1 mm × 10 mm PGC guard column functioning as a trap for the analytes. The loading solvent was Milli-Q water at 125 μl/min. After 3 min, the sample was switched into the separation column. The F2-isoprostanes were separated in 20 min using a linear solvent gradient comprising water, methanol, acetonitrile and ammonium hydroxide at a pH of 9.5 and a flow of 50 μl/min The limit of detection (calculated as 3S/N) was approximately 40 pM (14 pg/ml). The assay was linear within the examined range (18–450 pg/ml), using CSF spiked with iPF2α-III standard (r2 > 0.995). Repeatability data were calculated for CSF spiked to 90 pg/ml and the relative standard deviation (RSD) obtained was 3% (n = 6).
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| 7. |
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| 8. |
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| 9. |
- Ericsson, Olle, et al.
(författare)
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Clinical validation of a novel automated cell-free DNA screening assay for trisomies 21, 13, and 18 in maternal plasma.
- 2019
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Ingår i: Prenatal diagnosis. - : Wiley. - 1097-0223 .- 0197-3851. ; 39:11, s. 1011-1015
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate clinical performance of a new automated cell-free (cf)DNA assay in maternal plasma screening for trisomies 21, 18, and 13, and to determine fetal sex.Maternal plasma samples from 1200 singleton pregnancies were analyzed with a new non-sequencing cfDNA method, which is based on imaging and counting specific chromosome targets. Reference outcomes were determined by either cytogenetic testing, of amniotic fluid or chorionic villi, or clinical examination of neonates.The samples examined included 158 fetal aneuploidies. Sensitivity was 100% (112/112) for trisomy 21, 89% (32/36) for trisomy 18, and 100% (10/10) for trisomy 13. The respective specificities were 100%, 99.5%, and 99.9%. There were five first pass failures (0.4%), all in unaffected pregnancies. Sex classification was performed on 979 of the samples and 99.6% (975/979) provided a concordant result.The new automated cfDNA assay has high sensitivity and specificity for trisomies 21, 18, and 13 and accurate classification of fetal sex, while maintaining a low failure rate. The study demonstrated that cfDNA testing can be simplified and automated to reduce cost and thereby enabling wider population-based screening.
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| 10. |
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| 11. |
- Hansson, Helena, 1968-
(författare)
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A Novel Miniaturised Dynamic Hollow-Fibre Liquid-Phase Micro-Extraction Method for Xenobiotics in Human Plasma Samples
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bioanalytical chemistry is a challenging field, often involving complex samples, such as blood, plasma, serum or urine. In many applications, sample cleanup is the most demanding and time-consuming step. In the work underlying this thesis a novel dynamic miniature extractor, known as a hollow-fibre liquid-phase microextractor (HF-LPME), was designed, evaluated and studied closely when used to clean plasma samples. Aqueous-organic-aqueous liquid extraction, in which the organic liquid is immobilised in a porous polypropylene membrane, was the principle upon which the extractor was based, and this is discussed in all the papers associated with this thesis. This type of extraction is known as supported-liquid membrane extraction (SLM). The aim of this work was the development of a dynamic system for SLM. It was essential that the system could handle small sample volumes and had the potential for hyphenations and on-line connections to, for instance, LC/electrospray-MS. The design of a miniaturised HF-LPME device is presented in Paper I. The extraction method was developed for some weakly acidic pesticides and these were also used for evaluation. In the work described in Paper II, the method was optimised on the basis of an experimental design using spiked human plasma samples. Paper III presents a detailed study of the mass-transfer over the liquid membrane. The diffusion through the membrane pores was illustrated by a computer-simulation. Not surprisingly, the more lipophilic, the greater the retention of the compounds, as a result of dispersive forces. The main focus of the work described in Paper IV was to make the HF/LPME system more versatile and user-friendly; therefore, the extractor was automated by hyphenation to a SIA system.
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| 12. |
- Hansson, Helena, et al.
(författare)
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Dynamic hollow-fibre liquid phase microextraction for human plasma samples automated by sequential injection analysis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents an easily handled, hollow-fibre liquid phase microextraction (HF-LPME) sample clean-up method, automated by the use of a programmable sequential injection analysis (SIA) system. Use of a SIA system significantly reduces the need for manual sample handling. This new type of clean-up system was assessed and compared with manual HF-LPME for the extraction of acidic compounds (dinitrophenols) from human plasma, in terms of human intervention requirements, efficiency, repeatability and carry-over. Its application to a SIA system for basic compounds (b-blockers) is also presented. The sample aliquots collected off-line from the SIA system were subsequently subjected to separation with LC and the various analytes were detected with ESI-MS. Extraction efficiency values between 28 and 56% (RSD 5-10%, n = 7) were achieved for the dinitrophenol compounds after an extraction cycle of 58 min including a 30 min washing step. According to the MS analysis the SIA/HF-LPME method yielded clean chromatograms with no detectable interfering peaks. Ion suppression in positive ESI-MS was between 4 and 21% when tested on extracts with b-blockers.
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| 13. |
- Harang, Valérie, 1966-
(författare)
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Aspects of Optimisation of Separation of Drugs by Chemometrics
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Statistical experimental designs have been used for method development and optimisation of separation. Two reversed phase HPLC methods were optimised. Parameters such as the pH, the amount of tetrabutylammonium (TBA; co-ion) and the gradient slope (acetonitrile) were investigated and optimised for separation of erythromycin A and eight related compounds. In the second method, a statistical experimental design was used, where the amounts of acetonitrile and octane sulphonate (OSA; counter ion) and the buffer concentration were studied, and generation of an α-plot with chromatogram simulations optimised the separation of six analytes.The partial filling technique was used in capillary electrophoresis to introduce the chiral selector Cel7A. The effect of the pH, the ionic strength and the amount of acetonitrile on the separation and the peak shape of R- and S-propranolol were investigated.Microemulsion electrokinetic chromatography (MEEKC) is a technique similar to micellar electrokinetic chromatography (MEKC), except that the microemulsion has a core of tiny droplets of oil inside the micelles. A large number of factors can be varied when using this technique. A screening design using the amounts of sodium dodecyl sulphate (SDS), Brij 35, 1-butanol and 2-propanol, the buffer concentration and the temperature as factors revealed that the amounts of SDS and 2-propanol were the most important factors for migration time and selectivity manipulation of eight different compounds varying in charge and hydrophobicity. SDS and 2-propanol in the MEEKC method were further investigated in a three-level full factorial design analysing 29 different compounds sorted into five different groups. Different optimisation strategies were evaluated such as generating response surface plots of the selectivity/resolution of the most critical pair of peaks, employing chromatographic functions, simplex optimisation in MODDE and 3D resolution maps in DryLab™.Molecular descriptors were fitted in a PLS model to retention data from the three-level full factorial design of the MEEKC system. Two different test sets were used to study the predictive ability of the training set. It was concluded that 86 – 89% of the retention data could be predicted correctly for new molecules (80 – 120% of the experimental values) with different settings of SDS and 2-propanol.Statistical experimental designs and chemometrics are valuable tools for the development and optimisation of analytical methods. The same chemometric strategies can be employed for all types of separation techniques.
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| 14. |
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| 15. |
- Hjälte, Lena, et al.
(författare)
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Initial emergency medical dispatching and prehospital needs assessment: a prospective study of the Swedish ambulance service
- 2007
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Ingår i: Eur J Emerg Med. - : Lippincott Williams & Wilkins, Ltd.. - 0969-9546 .- 1473-5695. ; 14:3, s. 134-41
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the setting of priorities and patients' need for the ambulance service. METHODS: A prospective, consecutive study was conducted during a 6-week period. The ambulance staff completed a questionnaire assessing each patient's need for prehospital care. In addition to the questionnaire, data were extracted from the ambulance medical records for each case. RESULTS: The study included 1977 ambulance assignments. The results show that there is a substantial safety margin in the priority assessments made by the emergency medical dispatch operators, where the ambulance staff support the safety margin for initial priorities, despite the lack of at-the-scene confirmation. At-the-scene assessments indicated that 10% of all patients had potentially life-threatening conditions or no signs of life, but the advanced life support units were not systematically involved in these serious cases. The results even showed that one-third of the patients for whom an ambulance was assigned did not need the ambulance service according to the assessment made by the ambulance staff. CONCLUSION: Using the criteria-based dispatch protocol, the personnel at the emergency medical dispatch centres work with a safety margin in their priority assessments for ambulance response. Generally, this 'overtriage' and safety margin for initial priority settings were supported as appropriate by the ambulance staff. According to the judgement of the ambulance staff, one-third of all the patients who were assigned an ambulance response did not require ambulance transport.
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| 16. |
- Hjälte, Lena, et al.
(författare)
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Why are people without medical needs transported by ambulance? A study of indications for pre-hospital care.
- 2007
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Ingår i: European journal of emergency medicine : official journal of the European Society for Emergency Medicine. - : Lippincott Williams & Wilkins, Ltd.. - 0969-9546 .- 1473-5695. ; 14:3, s. 151-6
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The purpose of this report was to describe the characteristics of patients transported by ambulance, in spite of being evaluated by the ambulance staff at the scene as not requiring prehospital care. A second aim was to compare these patients with those judged as being in need of this care. METHODS: Three ambulance service districts located in different rural and metropolitan geographical areas were included in the study and all three were covered by a single emergency dispatch centre. Following the dispatch of ambulances, the staff assessed and recorded the medical needs of the patients at the scene, according to a questionnaire developed for the study. In addition to the questionnaire, data were extracted from the ambulance medical records database for each patient. If the patients were just transported by ambulance without receiving any other prehospital intervention, they were assessed as not being in need of the emergency service. The evaluation included events at the scene and during transportation. The ambulance staff making the needs assessments were emergency medical technicians and registered nurses. In this report, 604 patients who did not require prehospital care are described and compared with the remaining group of patients who required this care (1373). For analysis, descriptive statistics were used to analyse the data. RESULTS: The ambulance staff assessed that, among patients reported by the emergency medical dispatch centre as having abdominal or urinary problems, 42% did not need the ambulance service. Even among intrahospital transports (patients for whom medical personnel made the request for an ambulance), 45% did not require ambulance transport, as judged by the ambulance staff. Among patients reported by the emergency medical dispatch centre as having chest pain or other heart symptoms or trauma/accidents, respectively, only small percentages (18%) and (17%) did not require the ambulance service, as assessed by the ambulance staff. Most of the patients without obvious medical needs had been allocated an ambulance response for nonurgent conditions, that is priority level 2 or 3, but patients without medical needs were even found at the highest priority level 1. Of the patients who did not require an ambulance, more than half (55%) would have been able to get to a hospital in their own car or by taxi, whereas the remainder of the patients needed a transport vehicle in which they could lie down, but which was not equipped and staffed like an ambulance. CONCLUSION: Among the patients transported by the emergency medical service system in the study areas, a significant percentage were judged by the ambulance staff as not being in need of prehospital interventions. The majority were transported by a fully equipped emergency medical ambulance to an emergency medical department at a hospital, without requiring any prehospital interventions either at the scene or during transportation. The emergency medical service organization has to develop clear criteria for the utilization of ambulance services that can be accepted and implemented by the dispatch centres and by healthcare personnel. These criteria need to include safety margins and at the same time enable the appropriate use of resources.
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| 17. |
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| 18. |
- Horvai, George, et al.
(författare)
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European analytical column no. 39
- 2011
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 400:6, s. 1539-1541
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Tidskriftsartikel (refereegranskat)
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Karlberg, Bo, et al.
(författare)
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European Analytical Column No. 35 (January 2007)
- 2007
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 388:3, s. 513-515
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Tidskriftsartikel (refereegranskat)
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| 23. |
- Karlberg, Bo, et al.
(författare)
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European analytical column No. 36 (January 2008)
- 2008
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 391:4, s. 1109-1112
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Tidskriftsartikel (refereegranskat)
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Kölhed, Malin, 1977-
(författare)
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Novel on-line mid infrared detection strategies in capillary electrophoretic systems
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Infrared absorption spectra can provide analytically useful information on a large variety of compounds, ranging from small ions to large biological molecules. In fact, all analytes that possess a dipole moment that changes during vibration are infrared-active. The infrared (IR) spectrum can be subdivided into far-, mid- and near- regions. The focus of attention in this thesis is the mid-IR region, in which the fundamental vibrations of most organic compounds are located, thus providing scope for positive structural identification. However, while such near-ubiquitous signals can be very useful for monitoring simple molecules in simple systems, they can be increasingly disadvantageous as the number of analytes and/or the complexity of the sample matrix increases. Thus, hyphenation to a separation system prior to detection is desirable. Paper I appended to this thesis presents (for the first time) the on-line hyphenation between Fourier transform infrared spectroscopy, FTIR, and capillary zone electrophoresis, CZE. CZE is a highly efficient separation technique that separates ionic analytes with respect to their charge-to-size ratio. It is most commonly performed in aqueous buffers in fused silica capillaries. Since these capillaries absorb virtually all infrared light an IR-transparent flow cell had to be developed. In further studies (Paper II) the applicability of CZE is expanded to include neutral analytes by the addition of micelles to the buffer, and micellar electrokinetic chromatography, MEKC, was successfully hyphenated to FTIR for the first time. Paper III describes an application of the on-line CZE-FTIR technique in which non-UV-absorbing analytes in a complex matrix were separated, identified and quantified in one run.Measuring aqueous solutions in the mid-IR region is not straightforward since water absorbs intensely in this region, sometimes completely, leaving no transmitted, detectable light. For this reason, quantum cascade lasers are interesting. These lasers represent a new type of mid-IR semiconducting lasers with high output power due to their ingenious design. The laser action lies within one conduction band (intersubband) and can be tailored to emit light in the entire mid-IR region using the same semiconducting material. To investigate their potential to increase the optical path length in aqueous solutions, these lasers were used with an aqueous flow system (Paper IV), and the experience gained in these experiments enabled hyphenation of such lasers to a CZE system (Paper V).
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| 29. |
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| 30. |
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| 31. |
- Mohabbati, Sheila, 1965-
(författare)
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Separation of Proteins with Capillary Electrophoresis in Coated Capillaries with and without Electroosmosis : Studies on Zone Broadening and Analytical Performances
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proteins have such structural features that they may interact with different types of surfaces by all possible forces, i.e., electrostatic, hydrogen bonding, hydrophobic. In this thesis two different types of coatings for fused silica capillaries aimed to eliminate such interactions have been studied. The first is a covalent, electroosmosis-free coating with polyacrylamide (PAA) and the second involves a non-covalent coating with the quaternary ammonium compound N, N-didodecyl –N, N- dimethylammonium bromide (DDAB) with a strong anodic electroosmosis. Optimal conditions regarding efficiency and resolution were established by variations of the composition and ionic strengths of buffers at pH below the isoelectric point of the proteins. To achieve high efficiency and resolution the choice of buffer constituents was extremely important. The PAA coating was very stable at neutral and acidic conditions. Ammonium acetate (0.12 M) and ammonium hydroxyacetate (0.15 M) both at pH 4 provided the best separations with plate numbers up to 1 700 000 plate/m that is among the highest reported in the literature. Capillaries coated with DDAB were stable enough to, without recoating, permit consecutive separations of the proteins up to 9 hours (90 injections). High apparent efficiencies (over 1 million plates/m) were achieved with ammonium acetate (0.07 M), ammonium hydroxyacetate (0.08 M) and sodium phosphate (0.1 M) at pH 4. Zone broadening was studied by determination of the variance contributions from all main parameters. Significant variances were contributions from longitudinal diffusion, capillary curvature, injection plug, detector time response and detector slit width while other variances, e.g., variances for Joule heat and vertical sedimentation were negligible. The remaining undetermined variance may have its origin in all types of relatively slow interactions including adsorption onto the capillary surfaces and protein-buffer component interactions. The results indicate that the latter is the main cause to zone broadening in protein separations.
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| 32. |
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| 34. |
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Veni, veni Emmanuel : Uppsala domkyrkas gosskör 100 år
- 2020
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Bok (populärvet., debatt m.m.)abstract
- Körsång har klingat genom seklerna och speglat samhället. 100-årsjubilerande Uppsala domkyrkas gosskör är en del av detta genom vardagligt slit, konstnärliga framgångar, söndagligt gudstjänstsjungande och musikalisk glädje. Klingande musikalisk verksamhet är också en del av en tradition för Uppsala universitet och har så varit under dess drygt 500-åriga tillvaro. Kyrka och universitet har följts åt i samarbete och samverkan där musiken ofta varit en gemensam nämnare. Boken innehåller en längre historik samt kortare bidrag från personer som varit och är engagerade i Uppsala domkyrkas gosskörs verksamhet.
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| 35. |
- Zacharisa, Constantinos K., et al.
(författare)
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Amperometric determination of cyanides at the low ppb level by automated preconcentration based on gas diffusion coupled to sequential injection analysis
- 2009
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Ingår i: Talanta. - : Elsevier BV. - 0039-9140 .- 1873-3573. ; 77, s. 1620-1626
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Tidskriftsartikel (refereegranskat)abstract
- A simple, sensitive method for determining free cyanides is described. The assay is based on automated gas diffusion of the analyte using sequential injection analysis (SIA) coupled to amperometric detection on a silverworking electrode. The effects of varying several parameters affecting the analytical procedure (including the flow rates of the donor and acceptor streams, the concentrations of the reagents and the sample volumes)were studied. The validity and quality of themethodwere also assessed, by examining its linearity, limits of detection and quantitation, precision, selectivity to potentially interfering substances. Its sensitivity can be enhanced by applying a simple preconcentration step, following which limits of detection were found to be 0.05–0.12gL−1. Application of the proposed assay to the analysis of tap, mineral and tablewater samples spiked at concentrations ranging from1 to 10gL−1 CN−, yielded satisfactory recoveries (88–112%).
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