Mathematical modelling as a tool for management in eutrophication control of shallow lakes

The eutrophication model Delwaq-Bloom-Switch is developed to be a functional tool for water management. Therefore it includes nutrients, algal biomass and composition as well as water transparency. A module describing the interaction between water and bottom gives the model the flexibility to deal with measures, such as a decrease of the external phosphorus loading and flushing with water differing in composition from the lake water. This paper focuses on the functional aspects of the model, the results of an application on Lake Veluwe, The Netherlands, and the implications for water management.With one set of coefficients DBS reproduces the most important characteristics of Lake Veluwe for a period of two years before measures (reduction of the external loading and flushing during the winter months) and eight years after the measures. The phosphorus concentration decreased and became growth limiting for algae instead of nitrogen and light. Both in measurements and modelling results, the algal composition changed from blue-green algae dominance to green algae and diatom dominance. Lake Veluwe had a relatively short transient phase after reduction of external loading, because high nitrate concentrations in the flushing water inhibited a long period with high phosphorus releases from the bottom.Model calculations were carried out to investigate the effects of fish stock management and optimization of flushing. Both measures are promising.     

Water quality modelling of the western Scheldt estuary

In 1987 the National Institute for Coastal and Marine Management (theNetherlands) initiated the SAWES project (Systems Analysis WEstern Scheldt).The main goals of the project were to acquire knowledge with respect to thepollution problems in the Scheldt estuary and to apply this knowledge tomanagement issues of the Scheldt on an operational level. The main interestwas to understand quantitatively the relation between inputs of pollutingsubstances and effects on the ecosystem. In the framework of the project, awater quality model for the Scheldt estuary was made. In 1995, the modelarea was expanded to include the Belgian coastal region at the mouth of theestuary. The model calculates the fate of discharged substances andestablishes the relation between pollution inputs and the resulting waterquality, including general water quality (oxygen, pH, alkalinity, major ionchemistry and nutrients) as well as pollutant concentrations. The modelincorporates all chemical processes which affect these concentrations,including the precipitation/dissolution of metal sulphides which to a largeextent controls the fate of trace metals. Based on calibration andverification exercises, it has been shown that the model provides a goodrepresentation of the physical and chemical processes taking place withinthe estuary and can therefore be used to support policy development for theestuary. For example, the model can compute how the water and sedimentquality in the estuary will respond to reduced inputs of waste or to suchhuman activities as dredging. This revised version was published online in July 2006 with corrections to the Cover Date.     

Remote sensing as a tool for assessing water quality in Loosdrecht lakes

The underwater light field in 7 lakes in the Loosdrecht lake area was measured in situ. Subsurface upwelling irradiance and irradiance reflectance, together with estimations of scattering and laboratory measurements of absorption by aquatic humus and particulate matter, enabled an analysis of the spectral signature of these waters. Aircraft imaging spectrometer measurements of upwelling radiance at 1 km altitude were used to simulate the PMI Chlorophyll #1, the CAESAR Inland Water Mode spectral bandsets and the Thematic Mapper bands 1 to 4. This made it possible to compare the effects of spectral band width and selection on the estimation of water quality parameters. Correlations increased to r > 0.94, at a significance level of 1% for the simulated C-IWM data with the 6 water quality parameters. Images of the PMI Chlorophyll #1 and of the TM were analysed and found to be in accordance with the statistical modelling results.A significant increase in correlation of remote sensing data with water quality parameters can be achieved through the selective use of 10 to 20 nm wide bands in the spectral range of 500 to 720 nm in these eutrophic waters. Sum of chlorophyll a and phaeopigments, seston dry weight, Secchi disc transparency, and coefficients for vertical attenuation of light, absorption and scattering can be estimated accurately. TM image data for water quality assessment is of limited use due to the relatively low spectral and radiometric resolution. However, the revisit capability and relatively low price per area are positive aspects of these satellite images.Abbreviations CAESAR = CCD Airborne Experimental Scanner for Applications in Remote sensing - C-IWM = CAESAR Inland Water Mode - CCD = charge coupled device - EOS-A = Earth Observation System Platform A - PAR = photosynthetically active radiation from 400–700 nm. - PMI = Programmable Multispectral Imager - RSLL = Remote Sensing Loosdrecht Lakes Project - SPOT = Systeme Pour l'Observation de la Terre - SPOT-HRV = Sensor on board of the SPOT satellite - TM = Thematic Mapper instrument aboard the Landsat 5 satellite     

Short-term variations in the physiological state of phytoplankton [2pt] in a shallow temperate estuary

Short-term changes in the photosynthetic carbon metabolism and physiological state of phytoplankton were studied over a summer fortnight-long period in the Urdaibai estuary (Bay of Biscay) and related to observed environmental patterns. Day-to-day variability in the hydrographical and biological features of the estuary during the study period was due to changes in meteorological and tidal conditions. Phytoplankton biomass and primary production increased with the improvement of weather, i.e., light conditions, during neap tides. Thus a mixed bloom of cryptophyceans, Euglena sp., and the dinoflagellate Peridinium foliaceum developed in the middle and upper estuary. Photosynthetic responses of phytoplankton were related to the time-scale of changes in light regime. Allocation of photosynthate to major macromolecular classes (LMWM, lipid, polysaccharide, and protein), like phytoplankton biomass and primary production, showed strong spatio-temporal variability. High carbon fixation into low molecular weight metabolites was associated with growth limitation by low light. The relative incorporation of photosynthetic carbon into proteins increased at the beginning of the phytoplankton bloom but overall, it was rather constant. However, carbon allocation into storage products such us lipid or polysaccharide increased when carbon and energy produced under optimal growth conditions exceeded what could be assimilated into protein. These patterns are explained by both spatio-temporal changes in the environmental conditions and species-specific differences. In general, daily variability appeared to be more important than diurnal periodicity in the physiological responses of phytoplankton. Results from this study show that phytoplankton photosynthesis and carbon metabolism are simultaneously affected by biotic and abiotic factors, although short-term light fluctuations may have a major influence on the physiological state of phytoplankton in the Urdaibai estuary.     

Neural networks as a tool for control and management of a biological reactor for treating hydrogen sulphide

Based on an experimental database consisting of 194 daily cases, artificial neural networks were used to model the removal efficiency of a biofilter for treating hydrogen sulphide (H₂S). In this work, the removal efficiency of the reactor was considered as a function of the changes in the air flow and concentration of H₂S entering the biofilter. In order to obtain true representative values, the removal efficiencies (outputs) were measured 24 h after each input was changed. A MLP (multilayer perceptron 2-2-1) model with two input variables (unit flow and concentration of the contaminant fed into the biofilter) rendered good prediction values with a determination coefficient of 0.92 for the removal efficiency within the range studied. This means that the MLP model can explain 92% of the overall variability detected in the biofilter corresponding to a wide range of operating conditions.     

Variations in the water quality of a small urban tropical catchment: implications for load estimation and water quality monitoring

This paper presents findings on the quality of runoff draining a small urban tropical catchment in Singapore. Variations in runoff quality were studied by continuous, regular and storm event water sampling over a period of eleven months for suspended sediment, nutrient and inorganic variables. Storm events and anthropogenic activities exerted the most influence on runoff quality. Concentration-discharge rating relationships were derived to assess the rating curve method for calculating load of the variables monitored. The poor rating relationships obtained indicated that the method was not suitable for load estimation in this catchment. Instead, an interpolation method was used to calculate sediment loads. The preliminary results highlighted the importance of conducting small-scale, relatively short-term studies to identify and assess specific water quality problems facing each catchment. Such a sampling strategy might be more useful than either routine or continuous sampling in the context of planning more detailed monitoring strategies and management options suitable for disturbed catchments.     

Biological quality of waters from an impacted tropical watershed (middle Rio Doce basin,southeast Brazil), using benthic macroinvertebrate communities as an indicator

Taking the watershed as the unit for intervention and conservation, in this study we assess water quality along a stretch of impacted watershed of considerable economic importance, the middle Rio Doce basin, using the benthic macroinvertebrate community, along with physical and chemical characteristics as parameters, for the classification of 20 sampling stations. The results showed that parameters often used in temperate regions are also useful to assess water quality in tropical ecosystems, where no specific methodology has yet been developed. In spite of a clear distinction between stations of good and bad quality, the multimetric biological analysis alone was not sensitive enough to identify intermediate conditions. Grouping similar and dissimilar stations by Cluster analysis of physical and chemical variables and biological data, however, it was possible to distinguish three categories based on the biological quality of the water: (1) stations with poor quality water; (2) stations with high quality water, and (3) stations with water of intermediate quality. Classifications of water quality of this sort will hopefully assist decision-makers in defining restoration/conservation strategies, and will provide an important tool for monitoring biodiversity and water quality in tropical watersheds.     

Microarray-based genetic identification of beneficial organisms as a new tool for quality control of laboratory cultures

The use of beneficial organisms to help control pests and pathogens in field and greenhouse crops is constantly increasing. Insects and mites are commonly used as beneficial organisms and, nowadays, rearing companies have to produce them in large quantities. Because of the peculiarities of laboratory culture conditions, the quality of lab-reared organisms generally degrades over time. To maintain high fitness levels, cultures are refreshed with field specimens at regular intervals. However, this bears the risk of contaminating laboratory cultures with species or strains other than the intended natural enemy. To ensure that the correct species is produced and also to facilitate surveys after field release, we have developed a diagnostic microarray for identification of beneficial species. Probes have been designed from the different haplotypes of a fragment of the mitochondrial cytochrome oxidase I (COI) gene of each species. Hybridization of labeled PCR amplicons of COI on the microarray chip allows precise identification of 28 economically relevant arthropod species.     

Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale

Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.     

Water chemistry variability in the lower intertidal zone [-2pt] of an estuary in the Seto Inland Sea,Japan: seasonal patterns of nutrients and particulate compounds

From April 1994 to April 1996, we carried out monthly surveys on the physical and chemical variability of ebbing water at two intertidal stations near the emerged tidal flat and surface water at a nearby subtidal station, in a tidal estuary of the Seto Inland Sea, Japan. The fresh water runoff was a major source of new nitrogen (nitrate+nitrite = –2.1 × salinity + 74.3, r ² = 0.76, p < 0.001, at the inner intertidal station). In contrast, the absence or weak correlation of ammonium, phosphate and silicate with salinity in ebbing water highlighted the importance of in situ biologically-mediated processes, including the excretory activity of intertidal dominant bivalves (Ruditapes philippinarum and Musculista senhousia) and primary producer nutrient uptake. Among suspended particulate matter (SPM), the negative correlation of Chl a with salinity (p< 0.001) suggested that an upper intertidal zone, where high microphytobenthic assemblages occur, may represent a considerable source of microalgal biomass. Whereas, a stronger correlation of POC with pheo-pigments (r ² 0.92) than with Chl a (r ² 0.44), a low fraction of living phyto-Carbon (ca. 5%) and a high pheo-pigment/Chl a ratio (ca. 3) indicated a high portion of refractory algal material and a close water–sediment coupling on the flat, in which abundant macrozoobenthos is likely to play an important role. In spite of the strong variability of this ecosystems, this study also demonstrated that highly significant seasonal patterns can be recognized in our study area. However, patterns varied depending on the different nutrient species, SPM and sites. In ebbing water, ammonium concentrations were significantly higher in the cold period (i.e. November–April: water temperature 10.0 ± 4.4 °C), when primary producer biomass decreases, while Chl a and pheo-pigment content were 4.3 and 4.8 higher in the warm period (May–October: water temperature 23.5 ± 4.2 °C), respectively. At the subtidal site, nutrients were 1.9 (silicate)–2.9 (phosphate) and SPM was 1.8 (POC)–2.1 (pheo-pigments) times higher in the warm period. On an annual basis, mean pheo-pigment and POC content was 12–25 times and 4–8 times higher on the intertidal zone than on the subtidal zone, respectively, while nutrient concentrations were within the same order of magnitude. Such a qualitative difference (i.e. nutrients vs. SPM) between sites suggests that particle deposition and/or removal is likely to occur along the estuary, resulting in a limited SPM content at the surface layer of the subtidal site, while nutrients are more directly transported into the surface layer of the subtidal zone by lower salinity water mass intrusion from the intertidal zone, most importantly during the warm period.     

Light-induced self-assemblies suitable for photodimerization and their light-induced [2+2] cycloaddition: Light as a control factor of crystal growth

The reaction of Cd(NO₃)₂ and CF₃COONH₄ with bpe (trans-1,2-(bis(4-pyridyl)ethene)) ligands was investigated for a light-induced solid-state [2+2] cycloaddition reaction. The three structures (1 [Cd(bpe)₂(CF₃COO)₂]_n, 2 [Cd(bpe)₂(NO₃)₂]_n, and 3 [Cd(NO₃)(μ-NO₃)(H₂O)(bpe)_1.5]_n) formed in light while only compound 1 (or 1-dark) was formed in the dark. All three compounds were completely transformed to the final [2+2] cycloaddition products containing rctt-tetrakis(4-pyridyl)cyclobutane (rctt-tpcb; rctt means regional cis, trans, and trans of the four pyridyl groups attached to the cyclobutane ring) in solution under a natural light after 4 weeks. Among the final products, only one 3-D structure (4 [{Cd(rctt-tpcb)₂(NO₃)₂}{Cd(rctt-tpcb)₂(OH)₂}]_n) with a good crystallinity was determined by the X-ray diffraction technique. These observations were also in line with the spectroscopic results such as ¹H NMR. Meanwhile, 3 was also prepared separately and exposed to natural light. X-ray and NMR studies showed that 3 was completely transformed to 4 containing rctt-tpcb by a light-induced cycloaddition reaction for the 4 weeks. The reaction progress was further monitored by fluorescent spectroscopy. 1-dark also underwent the solid-state [2+2] cycloaddition under the natural light over four weeks.     

Development of molecularly imprinted polymers as tailored templates for the solid-state [2+2] photodimerization

In this study, a molecularly imprinted polymer (MIP) was prepared to selectively template the [2+2] photodimerization of trans-1,2-bis(4-pyridyl)ethylene. First, an MIP selective for rctt-tetrakis(4-pyridyl)cyclobutane, which is the [2+2] photodimerization product of trans-1,2-bis(4-pyridyl)ethylene, was prepared from methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). The non-covalent MIP showed enhanced affinity for both the templating agent, rctt-tetrakis(4-pyridyl)cyclobutane, and the alkene precursor, trans-1,2-bis(4-pyridyl)ethylene. The solid-state photodimerization reaction proceeded in significantly higher yields in the presence of the MIP. Control reactions carried out in the absence of polymer gave no product, and reactions carried out in the presence of a non-imprinted polymer and an MIP imprinted with a different template, 3-hydroxymethylpyridine, gave much lower yields of the cyclobutane photodimerization product. The outcome of the MIP-templated photodimerization reaction was strongly influenced by the binding site heterogeneity of the non-covalently imprinted polymers. For example, higher yields were observed with decreasing olefin loadings levels on the MIPs. This binding site heterogeneity was characterized via application of the Freundlich binding model to the experimentally measured binding isotherms. These confirmed that the non-covalent MIPs had very few high-affinity binding sites, which greatly limits the capacity and ultimately the utility of these materials as templates in synthetic organic applications.     

Molecular modelling design,synthesis and cytotoxic evaluation of certain substituted 2-(3,4,5-triacetoxybenzoylamino)benzo[d]thiazole and 2-(galloylamino)benzo[d]thiazole derivatives having potential topoisomerase-I inhibitory activity

New 2-(3,4,5-triacetoxybenzoylamino)benzothiazoles (4a~5f) and 2-(galloylamino)benzothiazoles (6a~7f), were designed as topoisomerase-I inhibitors. Compare/fit studies between these molecules and the generated topoisomerase-I inhibitors hypothesis revealed that 4a~5f have higher fitting values than (6a~7f). Also, docking of 4a~7f with the topoisomerase-I enzyme prioritized the higher activity of (4a~5f) than (6a~7f). These molecules were synthesized and biologically evaluated for their in vitro cytotoxic activity against Hela and MCF7 human cancer cell lines in comparison to Camptothecin (topo-I inhibitor) and doxorubicin (topo-II inhibitors) as reference drugs. Such screening revealed that compounds 4d, 4e, 4h, 5b, 5c and 5e have comparable higher cytotoxic activity in both cultures than these reference drugs. The highest active molecule was 5f that gave 1.5 folds higher cytotoxic activity against Hela cell cultures and 1.9 folds higher activity against MCF7 cell lines than doxorubicin and 1.6 folds and 2.2 folds higher activity towards the two respective cultures than Camptothecin.     

Effects of elevated [CO2] on forest growth and carbon storage: a modelling analysis of the consequences of changes in litter quality/quantity and root exudation

Many researchers have proposed that the stimulus of plant growth under elevated [CO₂] observed in short-term experiments will be moderated in the longer term by a reduction in soil nitrogen (N) availability linked to decreased litter quality and/or increased litter production. However, these negative feedbacks may be offset to some extent by a stimulus in N fixation linked to increased root exudation. The aim of this modelling study is to examine how changes in litter quality/quantity and root exudation –- if they occur –- will affect the CO₂ responses of net primary productivity and ecosystem carbon (C) storage on different timescales. We apply a model of C and N cycling in forest ecosystems (G’DAY) to stands of Norway spruce (Picea abies, L. Cast) growing at a N-limited experimental site at Flakaliden, Sweden, and draw the following conclusions: (1) in the absence of changes in litter quality and root exudation, the short-term CO₂ stimulus of litter quantity leads to only a minimal CO₂ stimulus of productivity or C storage in the medium term (≈ 20 years) and long term (≈ 200 years), because of constraints on soil N availability; (2) increasing plant nitrogen use efficiency (via a decrease in the N:C ratio of new litter) makes little impact on these results; (3) a significant CO₂ response in the medium term requires a substantial decrease in the N:C ratio of older litter, when it is approaching stabilisation as soil organic matter, although the long-term CO₂ response remains small; and (4) an increase in N fixation leads to a small effect on productivity in the short term, but a very large effect on both productivity and C storage in the long term. These results suggest that soil N constraints on the long-term CO₂-fertilisation effect can be overcome to a significant extent only by increases in N acquisition, although only modest increases may be required. This revised version was published online in June 2006 with corrections to the Cover Date.     

First data on rabbit dung as a water fertilizer in tropical fish culture and its effect on the growth of Oreochromis niloticus (Teleostei, Cichlidae)

The influence of rabbit dung on water quality, plankton occurrence and Nile tilapia growth (Oreochromis niloticus) was studied. pH and total alkalinity increased, dissolved oxygen concentration decreased but not below the critical level whilst the nitrogen parameters were not affected in a significant way. An important increase of plankton was recorded and was reflected in a decrease of transparency: the phytoplankton density was 2.7 times that of the controls. Tilapia growth rate in the manure treatments was 5.1 times that of the control group; no significant difference in survival rates was observed.     

Northern pike (Esox lucius L.) and aquatic vegetation,tools in the management of fisheries and water quality in shallow waters

Species and size composition of fish communities in shallow stagnant waters appear to be associated with the type, abundance and pattern of the vegetation. Man-induced impacts as eutrophication, and suppression of vegetation for reasons of water quantity management or angling pleasure may induce irreversible changes in the aquatic ecosystem. Water quality management should aim at restoring former pike habitat. Submerged weeds are important to that effect. These habitats are characterized by relatively low densities of fish stocks. Stocking of bream and carp interferes strongly with these objectives. With respect to fish stocks, interests of water quality and fishery management may be opposed.     

Mathematical modelling for the generation of L-[3-2H,3-13C]lactic acid isotopomers by erythrocytes exposed to either D-[1-13C]glucose or D-[6-13C]glucose in the presence of2H2O

Cytosolic purine nucleoside phosphorylase (PNPase) is a well known, and described enzyme which exists in a variety of organisms, both procaryotic and eucaryotic. More recently this enzyme was found in bovine liver mitochondria. The mitochondrial purine nucleoside phosphorylase was purified 63 fold and has a molecular weight of 48–60 kD. From Lineweaver-Burk plots apparent K_m's of 23M for inosine, 42 M for deoxyinosine, 40 M for phosphate, 2 M for hypoxanthine, and 163 M for ribose-1-phosphate were calculated. Both 8-aminoguanosine (K_i=0.5 M) and araG (K_i=381 M) are inhibitors of the enzyme. The protein's isoelectric point (pI) was calculated at a pH of 4.2. Preliminary immunological work showed no cross-reactivity between epitopes on the mitochondrial protein and those on PNPase from human erythrocytes. The apparent K_m's calculated for the mitochondrial enzyme are,with the exception of that using hypoxanthine, within the range commonly associated with K_m's from the cytosolic species. The mitochondrial enzyme's molecular weight and pI are less than normally described. The enzyme's isolation from mitochondria, together with several unique characteristics, suggest that it is a separate protein from that found in the cytosol.     

Characterisation of the phenolic profile of Boerhaavia diffusa L. by HPLC-PAD-MS/MS as a tool for quality control

Phenolic acids and flavonols of nine leaf and three root samples of Boerhaavia diffusa L., collected at different locations and subjected to several drying procedures, were characterised by reversed-phase HPLC-PAD-ESI/MS for the first time. Ten phenolic compounds were identified: 3,4-dihydroxy-5-methoxycinnamoyl-rhamnoside, quercetin 3-O-rhamnosyl(1-->6)galactoside (quercetin 3-O-robinobioside), quercetin 3-O-(2"-rhamnosyl)-robinobioside, kaempferol 3-O-(2"-rhamnosyl)-robinobioside, 3,5,4'-trihydroxy-6,7-dimethoxyflavone 3-O-galactosyl(1-->2)glucoside [eupalitin 3-O-galactosyl(1-->2)glucoside], caffeoyltartaric acid, kaempferol 3-O-robinobioside, eupalitin 3-O-galactoside, quercetin and kaempferol. Quantification was achieved by HPLC-PAD and two phenolic patterns were found for the leaves, in which quercetin 3-O-robinobioside or quercetin 3-O-(2"-rhamnosyl)-robinobioside was the major compound. Caffeoyltartaric acid was only present in the root material where it represented the main phenolic constituent. The results obtained demonstrated that the geographical origin (particularly the nature of the soil), but not the drying process, influences the phenolic composition.     

Discovery of {4-[4,9-bis(ethyloxy)-1-oxo-1,3-dihydro-2H-benzo[f]isoindol-2-yl]-2-fluorophenyl}acetic acid (GSK726701A), a novel EP4 receptor partial agonist for the treatment of pain

A novel series of EP₄ agonists and antagonists have been identified, and then used to validate their potential in the treatment of inflammatory pain. This paper describes these novel ligands and their activity within a number of pre-clinical models of pain, ultimately leading to the identification of the EP₄ partial agonist GSK726701A.     

1-[2-Hydroxy-3-octadecan-1'-oate]propyl-2'',2'',5'',5''-tetramethyl pyrolidine-N-oxyl-3''-carboxylate as a potential spin probe for membrane structure studies

The synthesis of a new minimum steric perturbing proxyl nitroxide, which is a derivative of glycerol and contains a stearic acid moiety, has been carried out. Its localization in model membrane L-alpha-dipalmitoyl phosphatidyl choline (DPPC) was ascertained with the help of ESR, DSC, 1H and 31P NMR techniques. The nitroxide was used for detecting the changes in the phase transition temperature of the model membranes in the presence and absence of drugs. The permeation of the vasodilating drug epinephrine has also been studied using this spin label. The results prove the potential applicability of the new spin probe in the spin labeling of biomembranes.