| 1. |
- Ivarsson, Patrik, et al.
(författare)
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Comparison of a voltammetric electronic tongue and a lipid membrane taste sensor
- 2001
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Ingår i: Analytica Chimica Acta. - 0003-2670 .- 1873-4324. ; 449:1-2, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- An electronic tongue based on voltammetry and a multichannel lipid membrane taste sensor based on potentiometry are compared using two aqueous examples: detergents and teas. The electronic tongue consists of four electrodes of different metals, a reference electrode and a counter electrode. The measurement principle is based on pulse voltammetry in which current is measured during the change of the amplitude of the applied potential. The taste sensor is based on eight different lipid/polymer membranes. The voltage difference between the electrodes and an Ag/AgCl reference electrode is measured when the current is close to zero. The responses from the two sensors systems are treated separately with multivariate data analysis based on principal component analysis and then merged to examine if further information could be extracted. It is shown that although the two sensor systems are about equal in separation ability in the two cases, extra information can be gained by combination of the two sensor systems. © 2001 Elsevier Science B.V. All rights reserved.
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| 2. |
- Ivarsson, Patrik, et al.
(författare)
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Discrimination of tea by means of a voltammetric electronic tongue and different applied waveforms
- 2001
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new sensor technology, an electronic tongue based on voltammetry has been developed at Linköping University. Three different metallic working electrodes are used in combination with a set of voltage "pulses", a waveform, to separate different samples. In this paper, three different waveforms are investigated. This is done through a study with nine different teas. Multivariate data analysis ((MVDA), principal component analysis (PCA)) is used to evaluate the data (the recorded current responses). The waveforms are large amplitude pulse voltammetry (LAPV), small amplitude pulse voltammetry (SAPV), and staircase voltammetry. Each method discriminated between the tea samples to some extent, but differently from each other. Best discrimination is achieved when the combination LAPV and staircase are merged together. When SAPV is included in the combination a worse separation is observed. It is clearly the case that more waveforms do not automatically lead to more information. © 2001 Elsevier Science B.V.
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| 3. |
- Ivarsson, Patrik
(författare)
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Electronic Tounges : New Sensor Technology in Household Appliances
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with a method to optimise the water, energy, and detergent consumption in a dishwasher and washing machine. A new sensor system, the voltammetric electronic tongue has been the key factor in the research. The electronic tongue is a sensor system that uses metal electrodes to apply a potential into a liquid, and a current response is obtained. Depending on the potential, the metal, and the liquid, different current responses are obtained. As the potential and the metals are known, unique "fingerprints" can be made for different liquids. These current responses are rather difficult to overview. Therefore, multivariate data analysis, especially principal component analysis (PCA), is used as evaluation tools.The electronic tongue can not (usually) measure a specific parameter in the liquid, but a"quality", which gives a summary of the liquid that can be used in many different contexts. The electronic tongue could also be used in many different ways in a dishwasher or washing machine. The most obvious way is to control the process in order to use the correct amount of water, energy, and detergent. Also, it can be imagined that other ways to use it would be to supervise parts of the process, such as water quality, detergent, and rinses in the machines.Sensors in household appliances have to be very durable, and the electronic tongue is suitable in harsh environments, as the only parts facing the liquid in the machines are metals and filling materials.The electronic tongue shows promising results when it comes to many of the ways to implement it in a dishwasher and washing machine.
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| 4. |
- Nowinski, Daniel, et al.
(författare)
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Keratinocytes inhibit expression of connective tissue growth factor in fibroblasts in vitro by an interleukin-1alpha dependent mecanism
- 2002
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 119:2, s. 449-455
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Tidskriftsartikel (refereegranskat)abstract
- The wound healing process concludes with downregulation of fibroblast activity. Clinical observations suggest that the regenerating epidermis suppresses this activity. An important regulator of fibroblast activity is the fibrogenic cytokine connective tissue growth factor. We hypothesized that epidermal keratinocytes may affect fibroblast activity via this cytokine. We demonstrate keratinocyte-mediated suppression of connective tissue growth factor at both the mRNA and protein levels by around 50% or more when fibroblasts were cultured in multiwell plates with keratinocyte cultures in accompanying semipermeable cell culture inserts, or stimulated by keratinocyte-conditioned media. Both basal and transforming-growth-factor-beta1-stimulated levels of connective tissue growth factor were inhibited. A 3 h coculture period with keratinocytes was sufficient to suppress connective tissue growth factor expression by fibroblasts, but the inhibition developed over a time period of around 16 h. The putative keratinocyte-derived factor(s) responsible for these effects was found to be soluble and stable. By analyzing cytokines secreted by keratinocytes we identified interleukin-1alpha as a potent inhibitor of connective tissue growth factor mRNA expression in fibroblasts. Involvement of this cytokine in keratinocyte-mediated connective tissue growth factor suppression was confirmed by using anti-interleukin-1alpha antibodies. Tumor necrosis factor alpha or prostaglandins did not appear to be involved. In conclusion, our results indicate that interleukin-1alpha secretion by keratinocytes provides a mechanism for the downregulation of connective tissue activity during the end-stage of wound healing, when epithelia coverage has developed over the wound area.
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