Publications by authors named "P Laamanen"

Objective: The study aimed to investigate the reliability of a portable toe pressure (TP) photoplethysmography device (PPG) by comparing it to a stationary laser Doppler flowmeter (LD) used in the Helsinki University Hospital. The study evaluated if lower limb arterial circulation could be reliably evaluated with the portable PPG which is more affordable and mobile than the stationary LD.

Methods: TPs were measured from 102 toes of 54 patients in the vascular surgery outpatient clinic, vascular surgery ward and interventional radiology recovery ward of Helsinki University Hospital.

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Previous research has shown that gaze cues facilitate responses to an upcoming target if the target location is compatible with the direction of the cue. Similar cueing effects have also been observed with central arrow cues. Both of these cueing effects have been attributed to a reflexive orienting of attention triggered by the cue.

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This study presents the use of quaternary ammonium bromides as additives in N-methylformamide (NMF) for the separation and quantification of chelating agents as copper complexes by capillary zone electrophoresis (CZE). The new quaternary ammonium bromides were synthesized in our laboratory and used for the first time for CZE applications performed in NMF media. The methods were developed and optimized for determination of six chelating agents (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes.

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A capillary zone electrophoresis (CZE) method for analyzing 11 chelating agents [beta-alaninediacetic acid (beta-ADA), trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), N-(2-hydroxyethyl)iminodiacetic acid (HEIDA), iminodiacetic acid (IDA), methylglycinediacetic acid (MGDA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N',N'-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)] as negatively charged copper(II) complexes has been established. Both conventional and alternative chelating agents were included in this study, because they are used side by side in industrial applications. In this study, didecyldimethylammonium bromide (DMDDAB) was successfully used as a flow reversal reagent for the first time in an aqueous CZE method based on phosphate BGE with UV spectrophotometric detection.

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A new method of nonaqueous capillary electrophoresis (NACE) with UV spectrophotometric detection was developed and optimized for the simultaneous determination of seven carboxylates (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N',N'-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. The method development was carried out by using a fused silica capillary. Background electrolyte (BGE) was optimized and the best separation achieved by using 30mmolL(-1) potassium bromide in N-methylformamide (NMF) at apparent pH (pH(app)) 10.

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