Detection of methotrexate using surface plasmon resonance biosensors for chemotherapy monitoring

Le méthotrexate (MTX), un agent anti-cancéreux fréquemment utilisé en chimiothérapie, requiert généralement un suivi thérapeutique de la médication (Therapeutic Drug Monitoring, TDM) pour surveiller son niveau sanguin chez le patient afin de maximiser son efficacité tout en limitant ses effets secondaires. Malgré la fenêtre thérapeutique étroite entre l’efficacité et la toxicité, le MTX reste, à ce jour, un des agents anti-cancéreux les plus utilisés au monde. Les techniques analytiques existantes pour le TDM du MTX sont coûteuses, requièrent temps et efforts, sans nécessairement fournir promptement les résultats dans le délai requis. Afin d’accélérer le processus de dosage du MTX en TDM, une stratégie a été proposée basée sur un essai compétitif caractérisé principalement par le couplage plasmonique d’une surface métallique et de nanoparticules d’or. Plus précisément, l’essai quantitatif exploite la réaction de compétition entre le MTX et une nanoparticule d’or fonctionnalisée avec l’acide folique (FA-AuNP) ayant une affinité pour un récepteur moléculaire, la réductase humaine de dihydrofolate (hDHFR), une enzyme associée aux maladies prolifératives. Le MTX libre mixé avec les FA-AuNP, entre en compétition pour les sites de liaison de hDHFR immobilisés sur une surface active en SPR ou libres en solution. Par la suite, les FA-AuNP liées au hDHFR fournissent une amplification du signal qui est inversement proportionnelle à la concentration de MTX. La résonance des plasmons de surface (SPR) est généralement utilisée comme une technique spectroscopique pour l’interrogation des interactions biomoléculaires. Les instruments SPR commerciaux sont généralement retrouvés dans les grands laboratoires d’analyse. Ils sont également encombrants, coûteux et manquent de sélectivité dans les analyses en matrice complexe. De plus, ceux-ci n’ont pas encore démontré de l’adaptabilité en milieu clinique. Par ailleurs, les analyses SPR des petites molécules comme les médicaments n’ont pas été explorés de manière intensive dû au défi posé par le manque de la sensibilité de la technique pour cette classe de molécules. Les développements récents en science des matériaux et chimie de surfaces exploitant l’intégration des nanoparticules d’or pour l’amplification de la réponse SPR et la chimie de surface peptidique ont démontré le potentiel de franchir les limites posées par le manque de sensibilité et l’adsorption non-spécifique pour les analyses directes dans les milieux biologiques. Ces nouveaux concepts de la technologie SPR seront incorporés à un système SPR miniaturisé et compact pour exécuter des analyses rapides, fiables et sensibles pour le suivi du niveau du MTX dans le sérum de patients durant les traitements de chimiothérapie. L’objectif de cette thèse est d’explorer différentes stratégies pour améliorer l’analyse des médicaments dans les milieux complexes par les biocapteurs SPR et de mettre en perspective le potentiel des biocapteurs SPR comme un outil utile pour le TDM dans le laboratoire clinique ou au chevet du patient. Pour atteindre ces objectifs, un essai compétitif colorimétrique basé sur la résonance des plasmons de surface localisée (LSPR) pour le MTX fut établi avec des nanoparticules d’or marquées avec du FA. Ensuite, cet essai compétitif colorimétrique en solution fut adapté à une plateforme SPR. Pour les deux essais développés, la sensibilité, sélectivité, limite de détection, l’optimisation de la gamme dynamique et l’analyse du MTX dans les milieux complexes ont été inspectés. De plus, le prototype de la plateforme SPR miniaturisée fut validé par sa performance équivalente aux systèmes SPR existants ainsi que son utilité pour analyser les échantillons cliniques des patients sous chimiothérapie du MTX. Les concentrations de MTX obtenues par le prototype furent comparées avec des techniques standards, soit un essai immunologique basé sur la polarisation en fluorescence (FPIA) et la chromatographie liquide couplée avec de la spectrométrie de masse en tandem (LC-MS/MS) pour valider l’utilité du prototype comme un outil clinique pour les tests rapides de quantification du MTX. En dernier lieu, le déploiement du prototype à un laboratoire de biochimie dans un hôpital démontre l’énorme potentiel des biocapteurs SPR pour utilisation en milieux clinique.

La planification métropolitaine et le transit-oriented development (TOD) : les nouveaux instruments de la gouvernance du Grand Montréal

Cette thèse croise les concepts de planification, de gouvernance et de transit-oriented development (TOD) par une étude de la production, de la mise en débat et de l'adoption du plan métropolitain d'aménagement et de développement (PMAD) de la Communauté métropolitaine de Montréal (CMM). Elle expose les résultats de quatre années de recherche qualitative sur les impacts de l'épisode du PMAD et de la stratégie TOD de la CMM sur les pratiques planificatrices et les processus décisionnels du Grand Montréal à l'échelle métropolitaine. Elle révèle que la planification métropolitaine et l'objectif de coordination du transport et de l'aménagement en général ainsi que le PMAD et le concept de TOD en particulier y sont des instruments de gouvernance. Les chapitres 2, 3 et 4 présentent la problématique, le terrain d'enquête et la démarche méthodologique de cette recherche. Le chapitre 5 relate l'épisode du PMAD en analysant son contenu, les procédures par lesquelles la CMM l'a produit, mis en débat et adopté, les réactions des parties prenantes de la région quant à ces aspects et la façon dont elles comptent assurer le suivi de sa mise en œuvre. Le chapitre 6 illustre comment cet épisode a fait du PMAD un instrument de gouvernance pour le Grand Montréal en décortiquant le rôle de la participation publique, des médias, des acteurs des milieux régional et local, des élus, de la CMM et de la société civile de la région au sein de ce processus de changement de registre de la planification et de la gouvernance les déployant sur des bases plus stratégiques et collaboratives. Le chapitre 7 montre que cet épisode a aussi fait du TOD un instrument de gouvernance pour le Grand Montréal en détaillant les tenants et aboutissants du processus d'appropriation, de marchand(is)age et d'instrumentalisation du concept par les élites politiques et techniques à des fins de marketing territorial et de construction de capital politique ouvrant la voie à la stabilisation d'une gouvernance en matière d'aménagement métropolitain. Il se dégage de cette thèse que ces profondes transformations que subissent actuellement la planification et la gouvernance exacerbent le caractère symbiotique de la relation qui les unit.

OFFLINE AND ONLINE SOLID PHASE EXTRACTION/PRECONCENTRATION OF INORGANICS

Solid phase extraction (SPE) is a powerful technique for preconcentration/removal or separation of trace and ultra trace amounts of toxic and nutrient elements. SPE effectively simplifies the labour intensive sample preparation, increase its reliability and eliminate the clean up step by using more selective extraction procedures. The synthesis of sorbents with a simplified procedure and diminution of the risks of errors shows the interest in the areas of environmental monitoring, geochemical exploration, food, agricultural, pharmaceutical, biochemical industry and high purity metal designing, etc. There is no universal SPE method because the sample pretreatment depends strongly on the analytical demand. But there is always an increasing demand for more sensitive, selective, rapid and reliable analytical procedures. Among the various materials, chelate modified naphthalene, activated carbon and chelate functionalized highly cross linked polymers are most important. In the biological and environmental field, large numbers of samples are to be analysed within a short span of time. Hence, online flow injection methods are preferred as they allow extraction, separation, identification and quantification of many numbers of analytes. The flow injection online preconcentration flame AAS procedure developed allows the determination of as low as 0.1 µg/l of nickel in soil and cobalt in human hair samples. The developed procedure is precise and rapid and allows the analysis of 30 samples per hour with a loading time of 60 s. The online FI manifold used in the present study permits high sampling, loading rates and thus resulting in higher preconcentration/enrichment factors of -725 and 600 for cobalt and nickel respectively with a 1 min preconcentration time compared to conventional FAAS signal. These enrichment factors are far superior to hitherto developed on line preconcentration procedures for inorganics. The instrumentation adopted in the present study allows much simpler equipment and low maintenance costs compared to costlier ICP-AES or ICP-MS instruments.

Spectroscopic Investigation of Tooth Caries and Demineralization

Dental caries persists to be the most predominant oral disease in spite of remarkable progress made during the past half- century to reduce its prevalence. Early diagnosis of carious lesions is an important factor in the prevention and management of dental caries. Conventional procedures for caries detection involve visual-tactile and radiographic examination, which is considered as “gold standard”. These techniques are subjective and are unable to detect the lesions until they are well advanced and involve about one-third of the thickness of enamel. Therefore, all these factors necessitate the need for the development of new techniques for early diagnosis of carious lesions. Researchers have been trying to develop various instruments based on optical spectroscopic techniques for detection of dental caries during the last two decades. These optical spectroscopic techniques facilitate noninvasive and real-time tissue characterization with reduced radiation exposure to patient, thereby improving the management of dental caries. Nonetheless, a costeffective optical system with adequate sensitivity and specificity for clinical use is still not realized and development of such a system is a challenging task.Two key techniques based on the optical properties of dental hard tissues are discussed in this current thesis, namely laser-induced fluorescence (LIF) and diffuse reflectance (DR) spectroscopy for detection of tooth caries and demineralization. The work described in this thesis is mainly of applied nature, focusing on the analysis of data from in vitro tooth samples and extending these results to diagnose dental caries in a clinical environment. The work mainly aims to improve and contribute to the contemporary research on fluorescence and diffuse reflectance for discriminating different stages of carious lesions. Towards this, a portable and compact laser-induced fluorescence and reflectance spectroscopic system (LIFRS) was developed for point monitoring of fluorescence and diffuse reflectance spectra from tooth samples. The LIFRS system uses either a 337 nm nitrogen laser or a 404 nm diode laser for the excitation of tooth autofluorescence and a white light source (tungsten halogen lamp) for measuring diffuse reflectance.Extensive in vitro studies were carried out on extracted tooth samples to test the applicability of LIFRS system for detecting dental caries, before being tested in a clinical environment. Both LIF and DR studies were performed for diagnosis of dental caries, but special emphasis was given for early detection and also to discriminate between different stages of carious lesions. Further the potential of LIFRS system in detecting demineralization and remineralization were also assessed.In the clinical trial on 105 patients, fluorescence reference standard (FRS) criteria was developed based on LIF spectral ratios (F500/F635 and F500/F680) to discriminate different stages of caries and for early detection of dental caries. The FRS ratio scatter plots developed showed better sensitivity and specificity as compared to clinical and radiographic examination, and the results were validated with the blindtests. Moreover, the LIF spectra were analyzed by curve-fitting using Gaussian spectral functions and the derived curve-fitted parameters such as peak position, Gaussian curve area, amplitude and width were found to be useful for distinguishing different stages of caries. In DR studies, a novel method was established based on DR ratios (R500/R700, R600/R700 and R650/R700) to detect dental caries with improved accuracy. Further the diagnostic accuracy of LIFRS system was evaluated in terms of sensitivity, specificity and area under the ROC curve. On the basis of these results, the LIFRS system was found useful as a valuable adjunct to the clinicians for detecting carious lesions.

A Study on the Efficiency of Islamic Economic Instruments in Selected Islamic Countries

Department of Applied Economics,Cochin University of Science and Technology

Modelling of Ultraviolet and Vissible Emissions in Comets

Comets are the spectacular objects in the night sky since the dawn of mankind. Due to their giant apparitions and enigmatic behavior, followed by coincidental calamities, they were termed as notorious and called as `bad omens'. With a systematic study of these objects modern scienti c community understood that these objects are part of our solar system. Comets are believed to be remnant bodies of at the end of evolution of solar system and possess the material of solar nebula. Hence, these are considered as most pristine objects which can provide the information about the conditions of solar nebula. These are small bodies of our solar system, with a typical size of about a kilometer to a few tens of kilometers orbiting the Sun in highly elliptical orbits. The solid body of a comet is nucleus which is a conglomerated mixture of water ice, dust and some other gases. When the cometary nucleus advances towards the Sun in its orbit the ices sublimates and produces the gaseous envelope around the nucleus which is called coma. The gravity of cometary nucleus is very small and hence can not in uence the motion of gases in the cometary coma. Though the cometary nucleus is a few kilometers in size they can produce a transient, extensive, and expanding atmosphere with size several orders of magnitude larger in space. By ejecting gas and dust into space comets became the most active members of the solar system. The solar radiation and the solar wind in uences the motion of dust and ions and produces dust and ion tails, respectively. Comets have been observed in di erent spectral regions from rocket, ground and space borne optical instruments. The observed emission intensities are used to quantify the chemical abundances of di erent species in the comets. The study of various physical and chemical processes that govern these emissions is essential before estimating chemical abundances in the coma. Cameron band emission of CO molecule has been used to derive CO2 abundance in the comets based on the assumption that photodissociation of CO2 mainly produces these emissions. Similarly, the atomic oxygen visible emissions have been used to probe H2O in the cometary coma. The observed green ([OI] 5577 A) to red-doublet emission ([OI] 6300 and 6364 A) ratio has been used to con rm H2O as the parent species of these emissions. In this thesis a model is developed to understand the photochemistry of these emissions and applied to several comets. The model calculated emission intensities are compared with the observations done by space borne instruments like International Ultraviolet Explorer (IUE) and Hubble Space Telescope (HST) and also by various ground based telescopes.

Effects of manure quality and application forms on soil C and N turnover of a subtropical oasis soil under laboratory conditions

Our knowledge of the agricultural sustainability of the millennia-old mountain oases in northern Oman is restricted in particular with respect to C and N turnover. A laboratory study was conducted (1) to analyse the effects of rewetting and drying on soil microorganisms after adding different manures, (2) to investigate the effects of mulching or incorporating of these manures, and (3) to evaluate the relationships between C and N mineralisation rates and manure quality indices. During the first 9-day rewetting and drying cycle, i.e. the “mulch” period, the content of extractable organic C decreased by approximately 40% in all four treatments. During the second 9-day rewetting and drying cycle, i.e. the “incorporation” period, this fraction decreased insignificantly in almost all treatments. The control and mature manure treatments form the first pair with a low percentage of total organic C evolved as CO2 (0.3% in 18 days) and a considerable percentage of total N mineralised as NH4 and NO3 (1% in 18 days), the fresh and immature manure treatments form the second pair with a higher amount of total organic C evolved as CO2 (0.5% in 18 days) and no net N mineralisation. During the first 9-day rewetting and drying cycle, the contents of microbial biomass C and biomass N increased by approximately 150% in all four treatments. During the second 9-day rewetting and drying cycle, no further increase was observed in the control and immature manure treatments and a roughly 30% increase in the other two treatments.

Determination of yield and quality parameters of energy crops applying laboratory and field spectroscopy

A real-time analysis of renewable energy sources, such as arable crops, is of great importance with regard to an optimised process management, since aspects of ecology and biodiversity are considered in crop production in order to provide a sustainable energy supply by biomass. This study was undertaken to explore the potential of spectroscopic measurement procedures for the prediction of potassium (K), chloride (Cl), and phosphate (P), of dry matter (DM) yield, metabolisable energy (ME), ash and crude fibre contents (ash, CF), crude lipid (EE), nitrate free extracts (NfE) as well as of crude protein (CP) and nitrogen (N), respectively in pretreated samples and undisturbed crops. Three experiments were conducted, one in a laboratory using near infrared reflectance spectroscopy (NIRS) and two field spectroscopic experiments. Laboratory NIRS measurements were conducted to evaluate to what extent a prediction of quality parameters is possible examining press cakes characterised by a wide heterogeneity of their parent material. 210 samples were analysed subsequent to a mechanical dehydration using a screw press. Press cakes serve as solid fuel for thermal conversion. Field spectroscopic measurements were carried out with regard to further technical development using different field grown crops. A one year lasting experiment over a binary mixture of grass and red clover examined the impact of different degrees of sky cover on prediction accuracies of distinct plant parameters. Furthermore, an artificial light source was used in order to evaluate to what extent such a light source is able to minimise cloud effects on prediction accuracies. A three years lasting experiment with maize was conducted in order to evaluate the potential of off-nadir measurements inside a canopy to predict different quality parameters in total biomass and DM yield using one sensor for a potential on-the-go application. This approach implements a measurement of the plants in 50 cm segments, since a sensor adjusted sideways is not able to record the entire plant height. Calibration results obtained by nadir top-of-canopy reflectance measurements were compared to calibration results obtained by off-nadir measurements. Results of all experiments approve the applicability of spectroscopic measurements for the prediction of distinct biophysical and biochemical parameters in the laboratory and under field conditions, respectively. The estimation of parameters could be conducted to a great extent with high accuracy. An enhanced basis of calibration for the laboratory study and the first field experiment (grass/clover-mixture) yields in improved robustness of calibration models and allows for an extended application of spectroscopic measurement techniques, even under varying conditions. Furthermore, off-nadir measurements inside a canopy yield in higher prediction accuracies, particularly for crops characterised by distinct height increment as observed for maize.

Evaluation of major feed resources in crop-livestock mixed farming systems, southern Ethiopia: Indigenous knowledge versus laboratory analysis results

Evaluation of major feed resources was conducted in four crop-livestock mixed farming systems of central southern Ethiopia, with 90 farmers, selected using multi-stage purposive and random sampling methods. Discussions were held with focused groups and key informants for vernacular name identification of feed, followed by feed sampling to analyse chemical composition (CP, ADF and NDF), in-vitro dry matter digestibility (IVDMD), and correlate with indigenous technical knowledge (ITK). Native pastures, crop residues (CR) and multi-purpose trees (MPT) are the major feed resources, demonstrated great variations in seasonality, chemical composition and IVDMD. The average CP, NDF and IVDMD values for grasses were 83.8 (ranged: 62.9–190), 619 (ranged: 357–877) and 572 (ranged: 317–743) g kg^(−1) DM, respectively. Likewise, the average CP, NDF and IVDMD for CR were 58 (ranged: 20–90), 760 (ranged: 340–931) and 461 (ranged: 285–637)g kg^(−1) DM, respectively. Generally, the MPT and non-conventional feeds (NCF, Ensete ventricosum and Ipomoea batatas) possessed higher CP (ranged: 155–164 g kg^(−1) DM) and IVDMD values (611–657 g kg^(−1) DM) while lower NDF (331–387 g kg^(−1) DM) and ADF (321–344 g kg^(−1) DM) values. The MPT and NCF were ranked as the best nutritious feeds by ITK while crop residues were the least. This study indicates that there are remarkable variations within and among forage resources in terms of chemical composition. There were also complementarities between ITK and feed laboratory results, and thus the ITK need to be taken into consideration in evaluation of local feed resources.

Prices versus exams as strategic instruments for competing universities

In this paper we investigate the optimal choice of prices and/or exams by universities in the presence of credit constraints. We first compare the optimal behavior of a public, welfare maximizing, monopoly and a private, profit maximizing, monopoly. Then we model competition between a public and a private institution and investigate the new role of exams/prices in this environment. We find that, under certain circumstances, the public university may have an interest to raise tuition fees from minimum levels if it cares for global welfare. This will be the case provided that (i) the private institution has higher quality and uses only prices to select applicants, or (ii) the private institution has lower quality and uses also exams to select students. When this is the case, there are efficiency grounds for raising public prices

Review of bio-particle manipulation using dielectrophoresis

During the last decade, large and costly instruments are being replaced by system based on microfluidic devices. Microfluidic devices hold the promise of combining a small analytical laboratory onto a chip-sized substrate to identify, immobilize, separate, and purify cells, bio-molecules, toxins, and other chemical and biological materials. Compared to conventional instruments, microfluidic devices would perform these tasks faster with higher sensitivity and efficiency, and greater affordability. Dielectrophoresis is one of the enabling technologies for these devices. It exploits the differences in particle dielectric properties to allow manipulation and characterization of particles suspended in a fluidic medium. Particles can be trapped or moved between regions of high or low electric fields due to the polarization effects in non-uniform electric fields. By varying the applied electric field frequency, the magnitude and direction of the dielectrophoretic force on the particle can be controlled. Dielectrophoresis has been successfully demonstrated in the separation, transportation, trapping, and sorting of various biological particles.

Probabilistic models to assist maintenance of multiple instruments

The paper discusses maintenance challenges of organisations with a huge number of devices and proposes the use of probabilistic models to assist monitoring and maintenance planning. The proposal assumes connectivity of instruments to report relevant features for monitoring. Also, the existence of enough historical registers with diagnosed breakdowns is required to make probabilistic models reliable and useful for predictive maintenance strategies based on them. Regular Markov models based on estimated failure and repair rates are proposed to calculate the availability of the instruments and Dynamic Bayesian Networks are proposed to model cause-effect relationships to trigger predictive maintenance services based on the influence between observed features and previously documented diagnostics