The effects of particulate ambient air pollution on the murine umbilical cord and its vessels: A quantitative morphological and immunohistochemical study

Previous studies have shown that particulate matter (PM) compromise birth weight and placental morphology. We hypothesized that exposing mice to ambient PM would affect umbilical cord (UC) morphology. To test this, mice were kept in paired open-top exposure chambers at the same location and ambient conditions but, in one chamber, the air was filtered (F) and, in the other, it was not (NF). UCs were analysed stereologically and by immunohistochemistry to localize isoprostane and endothelin receptors. The cords of mice from NF chambers were smaller in volume due to loss of mucoid connective tissue and decrease in volume of collagen. These structural changes and in umbilical vessels were associated with greater volumes of regions immunostained for isoprostane, ETAR and ETBR. Findings indicate that the adverse effects of PM on birth weight may be mediated in part by alterations in UC structure or imbalances in the endogenous regulators of vascular tone and oxidative stress. (C) 2012 Elsevier Inc. All rights reserved.

Ni catalyst on mixed support of CeO2-ZrO2 and Al2O3: Effect of composition of CeO2-ZrO2 solid solution on the methane steam reforming reaction

In this study, catalysts containing 5 wt.% Ni deposited on a support composed of a CeO2-ZrO2 solid solution deposited on alumina were tested in the steam reforming of methane. The supports, with various ratios of Ce to Zr, were prepared by co-precipitation of the oxide precursors, followed by calcination in synthetic air. The catalysts were then prepared by Ni impregnation of the supports. The prepared solids were characterized by temperature-programmed reduction with H-2 (TPR-H-2), in situ X-ray diffraction (XRD) and X-ray absorption near-edge structure (XANES) spectroscopy. The XRD analysis confirmed the formation of a solid solution between ZrO2 and CeO2. In the catalytic tests, it was found that catalysts with higher Ce content did not exhibit deactivation during 6 h of reaction. The catalyst with highest Ce content, Ni(0.8Ce0.2Zr)AI, provided the best result, with the highest rate of conversion of methane and the lowest carbon deposition, which may be partly due to the smaller Ni-0 crystallites in this sample and also the segregated CeO2 particles may have favored H2O adsorption which could lead to higher C gasification. (C) 2012 Elsevier B.V. All rights reserved.

Tectonic implications of the 1419 Ma Nova Guarita mafic intrusives paleomagnetic pole (Amazonian Craton) on the longevity of Nuna

The Nuna supercontinent was probably assembled in the Paleoproterozoic, but its paleogeography and the timing for its demise are stills matter of debate. A paleomagnetic and geochronological study carried out on the Mesoproterozoic Nova Guarita dyke swarm (northern Mato Grosso State, SW Amazonian Craton) provides additional constraints on the duration of this supercontinent. Paleomagnetic AF and thermal treatment revealed south/southwest (northeast) magnetic directions with downward (upward) inclinations for 19 analyzed sites. These directions are carried by PSD magnetite with high unblocking temperatures as indicated by additional magnetic tests, including thermomagnetic curves, hysteresis loops and the progressive acquisition of isothermal remanence in selected samples. A positive contact test with the host granite in one of the studied dykes further attests to the primary origin of the characteristic magnetic component. A mean site direction was calculated at D-m = 220.5 degrees, I-m = 45.9 degrees (alpha(95) = 6.5 degrees, K = 27.7), which yielded a paleomagnetic pole located at 245.9 degrees E, 47.9 degrees S (A(95) = 7.0 degrees). Ar-40/Ar-39 dating carried out on biotites from four analyzed dykes yielded well-defined plateau ages with a mean of 1418.5 +/- 3.5 Ma. The Nova Guarita pole precludes a long-lived Nuna configuration in which Laurentia, Baltica, North China, and Amazonia formed a long and continuous block as previously proposed for the Paleoproterozoic. It is nevertheless fully compatible with a SAMBA (Amazonia-Baltica) link at Mesoproterozoic times. (C) 2011 Elsevier B.V. All rights reserved.

On the relationship between neurocysticercosis and mesial temporal lobe epilepsy associated with hippocampal sclerosis: coincidence or a pathogenic relationship?

Neurocysticercosis (NCC) and mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) are two common worldwide forms of focal epilepsy. In regions where NCC is endemic, both diseases can be observed in the same patient. There is recent and growing evidence suggesting that NCC might contribute to or even cause MTLE-HS. In this article, we review the literature regarding NCC and temporal lobe epilepsy, specifically addressing the relationship between NCC and MTLE-HS. In addition, we review some scenarios where NCC seems to emerge as a causative agent or contributor to the development of MTLE-HS in some patients. This association is important because it may have an impact on the evaluation and treatment of a sizable proportion of patients with epilepsy. Insights from these clinical observations might also contribute to the understanding of the neurobiology of both NCC and MTLE-HS. We hope that our review might shed some light on this interesting interplay between two of the most common worldwide conditions associated with human focal epilepsy.

Simcluster: clustering enumeration gene expression data on the simplex space

Abstract Background Transcript enumeration methods such as SAGE, MPSS, and sequencing-by-synthesis EST "digital northern", are important high-throughput techniques for digital gene expression measurement. As other counting or voting processes, these measurements constitute compositional data exhibiting properties particular to the simplex space where the summation of the components is constrained. These properties are not present on regular Euclidean spaces, on which hybridization-based microarray data is often modeled. Therefore, pattern recognition methods commonly used for microarray data analysis may be non-informative for the data generated by transcript enumeration techniques since they ignore certain fundamental properties of this space. Results Here we present a software tool, Simcluster, designed to perform clustering analysis for data on the simplex space. We present Simcluster as a stand-alone command-line C package and as a user-friendly on-line tool. Both versions are available at: http://xerad.systemsbiology.net/simcluster. Conclusion Simcluster is designed in accordance with a well-established mathematical framework for compositional data analysis, which provides principled procedures for dealing with the simplex space, and is thus applicable in a number of contexts, including enumeration-based gene expression data.

Influence of myofascial pain on the pressure pain threshold of masticatory muscles in women with migraine

Objective: To evaluate the influence of myofascial pain on the Pressure Pain Threshold (PPT) of masticatory muscles in women with migraine. Methods: The sample comprised 101 women, ages ranging from 18 to 60 years, with an episodic migraine diagnosis previously confirmed by a neurologist. All patients were evaluated using Research Diagnostic Criteria for Temporomandibular Disorders to determine the presence of myofascial pain and were divided into 2 groups: group I (n=56), comprising women with a migraine, and group II (n=45), comprising women with a migraine and myofascial pain. Two more groups (49 asymptomatic women and 50 women with myofascial pain), matched for sex and race, obtained from a previous study, were added to this study. The PPT values of masseter and temporalis (anterior, middle, and posterior regions) muscles were recorded bilaterally using a pressure algometer. One-way analysis of variance and the Tukey test for pairwise comparisons were used in statistical analysis with a 5% significance level. Results: We found that all groups had significantly lower PPT values compared with asymptomatic women, with lower values seen in group II (women with migraine and myofascial pain). Women with a migraine and myofascial pain showed significantly lower PPT values compared with women with a migraine only, and also when compared with women with myofascial pain only. Discussion: Migraine, especially when accompanied by myofascial pain, reduces the PPT of masticatory muscles, suggesting the importance of masticatory muscle palpation during examination of patients with migraine.

Influence of psychosocial risk factors on the trajectory of mental health problems from childhood to adolescence: a longitudinal study

Background Longitudinal epidemiological studies involving child/adolescent mental health problems are scarce in developing countries, particularly in regions characterized by adverse living conditions. We examined the influence of psychosocial factors on the trajectory of child/adolescent mental health problems (CAMHP) over time. Methods A population-based sample of 6- to 13-year-olds with CAMHP was followed-up from 2002–2003 (Time 1/T1) to 2007–2008 (Time 2/T2), with 86 out of 124 eligible children/adolescents at T1 being reassessed at T2 (sample loss: 30.6%). Outcome: CAMHP at T2 according to the Child Behavior Checklist/CBCL’s total problem scale. Psychosocial factors: T1 variables (child/adolescent’s age, family socioeconomic status); trajectory of variables from T1 to T2 (child/adolescent exposure to severe physical punishment, mother exposure to severe physical marital violence, maternal anxiety/depression); and T2 variables (maternal education, child/adolescent’s social support and pro-social activities). Results Multivariate analysis identified two risk factors for child/adolescent MHP at T2: aggravation of child/adolescent physical punishment and aggravation of maternal anxiety/depression. Conclusions The current study shows the importance of considering child/adolescent physical punishment and maternal anxiety/depression in intervention models and mental health care policies.

Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae: a brief theoretical discussion of likely scenarios

Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.

Nuclear abnormalities in erythrocytes and morphometric indexes in the catfish Cathorops spixii (Ariidae) from different sites on the southeastern Brazilian coast

Nuclear abnormalities in erythrocytes (NAE) were taken as biomarkers in the catfish Cathorops spixii (Ariidae) sampled in an estuary little affected by human activity (Cananéia) and in three regions (Santos Channel: SC, Santos Bay: SB and São Vicente Channel: SVC) of the Santos-São Vicente estuary impacted by various anthropogenic activities. Increases in NAE were observed in fish from SC and SVC sampled in the summer period as compared with specimens from the Cananéia estuary. These results suggest the presence of genotoxic compounds in these regions. However, the absence of significant differences in micronuclei frequency reflects slight mutagenic effects in these individuals. It is possible that the lower NAE frequency in specimens from SB might be associated with the greater remobilization and dilution of chemicals in this region. The low frequency of NAE in C. spixii from the Cananéia estuary is in accordance with the slight anthropogenic influence in this system, and may be suggestive of the absence of genotoxic and mutagenic effects in these organisms.

Morphology and surface sedimentation on the upper and middle continental slope off Uruguay

This paper presents for the first time a morphological and surface sediment characterization of the Uruguayan outer continental shelf and slope. The study is based on a high-resolution coverage using hydrographical, geomorphological and sedimentological sampling and several textural and productivity proxies. Along slope terraces and an important canyon system characterizes continental slope morphology, indicating that across- and down-slope sedimentary processes control large-scale sedimentation. Terraces represent the prolongation of the Argentinean Contouritic Depositional System that vanishes in the study area, presumably as a result of the dynamic of the Brazil-Malvinas confluence. Canyons incised in the upper slope are likely related to low-stand sea level conditions. At the outer shelf and shallow upper slope (170-250 m depth), off-shelf sand transport is inferred from the distribution of relict sand and reworked biogenic gravel. In the upper continental slope, the northern region is characterized by an erosive environment controlled by a steep slope and the southward flowing Brazil current. In the south, a depositional environment is enhanced by the presence of a gentler slope and seaward incised canyons and is mainly controlled by hemipelagic processes associated with nutrient-rich Sub-Antarctic Waters (SAW), by its confluence with South Atlantic Central Waters (SACW) and by the Rio de la Plata’s (RdlP) influence. Additionally, within the upper slope, the occurrence of igneous-metamorphic cobbles and pebbles in canyon and mound lag deposits suggests the influence of glacial fluvial discharge and/or iceberg transport processes. In the middle slope, sedimentation is controlled by thermohaline-induced deep-water bottom currents. The decreasing influence of the erosive Antarctic Intermediate Water (AAIW) is evident in a northward diminution in grain size. The variety of transport and sedimentary processes identified reflect the control of the Brazil-Malvinas confluence zone and the Rio de la Plata’s discharge.

Glaciers and climate in northern Sweden during the 19th and 20th century

Our understanding of the climate of northern Sweden during the late Holocene is largely dependent on proxy-data series. These datasets remain spatially and temporally sparse and instrumental series are rare prior to the mid 19th century. Nevertheless, the glaciology and paleo-glaciology of the region has a strong potential significance for the exploration of climate change scenarios, past and future. The aim of this thesis is to investigate the 19th and 20th century climate in the northern Swedish mountain range. This provides a good opportunity to analyse the natural variability of the climate before the onset of the industrial epoch. Developing a temporal understanding of fluctuations in glacier front positions and glacier mass balance that is linked to a better understanding of their interaction and relative significance to climate is fundamental in the assessment of past climate. I have chosen to investigate previously unexplored temperature data from northern Sweden from between 1802 and 1860 and combined it with a temperature series from a synoptic station in Haparanda, which began operation in 1859, in order to create a reliable long temperature series for the period 1802 to 2002. I have also investigated two different glaciers, Pårteglaciären and Salajekna, which are located in different climatic environments. These glaciers have, from a Swedish perspective, long observational records. Furthermore, I have investigated a recurring jökulhlaup at the glacier Sälkaglaciären in order to analyse glacier-climate relationships with respect to the jökulhlaups. A number of datasets are presented, including: glacier frontal changes, in situ and photogrammetric mass balance data, in situ and satellite radar interferometry measurements of surface velocity, radar measurements, ice volume data and a temperature series. All these datasets are analysed in order to investigate the response of the glaciers to climatic stimuli, to attribute specific behaviour to particular climates and to analyse the 19th and 20th century glacier/climate relationships in northern Sweden. The 19th century was characterized by cold conditions in northern Sweden, particularly in winter. Significant changes in the amplitude of the annual temperature cycle are evident. Through the 19th century there is a marked decreasing trend in the amplitude of the data, suggesting a change towards a prevalence of maritime (westerly) air masses, something which has characterised the 20th century. The investigations on Salajekna support the conclusion that the major part of the 19th century was cold and dry. The 19th century advance of Salajekna was probably caused by colder climate in the late 18th and early 19th centuries, coupled with a weakening of the westerly airflow. The investigations on Pårteglaciären show that the glacier has a response time of ~200 years. It also suggests that there was a relatively high frequency of easterly winds providing the glacier with winter precipitation during the 19th century. Glaciers have very different response times and are sensitive to different climatic parameters. Glaciers in rather continental areas of the Subarctic and Arctic can have very long response times because of mass balance considerations and not primarily the glacier dynamics. This is of vital importance for analyzing Arctic and Subarctic glacier behaviour in a global change perspective. It is far from evident that the behaviour of the glacier fronts today reflects the present climate.

On the lifecycle of aerosol particles : Sources and dispersion over Scandinavia

Aerosol particles are likely important contributors to our future climate. Further, during recent years, effects on human health arising from emissions of particulate material have gained increasing attention. In order to quantify the effect of aerosols on both climate and human health we need to better quantify the interplay between sources and sinks of aerosol particle number and mass on large spatial scales. So far long-term, regional observations of aerosol properties have been scarce, but argued necessary in order to bring the knowledge of regional and global distribution of aerosols further. In this context, regional studies of aerosol properties and aerosol dynamics are truly important areas of investigation. This thesis is devoted to investigations of aerosol number size distribution observations performed through the course of one year encompassing observational data from five stations covering an area from southern parts of Sweden up to northern parts of Finland. This thesis tries to give a description of aerosol size distribution dynamics from both a quantitative and qualitative point of view. The thesis focuses on properties and changes in aerosol size distribution as a function of location, season, source area, transport pathways and links to various meteorological conditions. The investigations performed in this thesis show that although the basic behaviour of the aerosol number size distribution in terms of seasonal and diurnal characteristics is similar at all stations in the measurement network, the aerosol over the Nordic countries is characterised by a typically sharp gradient in aerosol number and mass. This gradient is argued to derive from geographical locations of the stations in relation to the dominant sources and transport pathways. It is clear that the source area significantly determine the aerosol size distribution properties, but it is obvious that transport condition in terms of frequency of precipitation and cloudiness in some cases even more strongly control the evolution of the number size distribution. Aerosol dynamic processes under clear sky transport are however likewise argued to be highly important. Southerly transport of marine air and northerly transport of air from continental sources is studied in detail under clear sky conditions by performing a pseudo-Lagrangian box model evaluation of the two type cases. Results from both modelling and observations suggest that nucleation events contribute to integral number increase during southerly transport of comparably clean marine air, while number depletion dominates the evolution of the size distribution during northerly transport. This difference is largely explained by different concentration of pre-existing aerosol surface associated with the two type cases. Mass is found to be accumulated in many of the individual transport cases studied. This mass increase was argued to be controlled by emission of organic compounds from the boreal forest. This puts the boreal forest in a central position for estimates of aerosol forcing on a regional scale.

Essays on the political economy of European integration

Recently, a rising interest in political and economic integration/disintegration issues has been developed in the political economy field. This growing strand of literature partly draws on traditional issues of fiscal federalism and optimum public good provision and focuses on a trade-off between the benefits of centralization, arising from economies of scale or externalities, and the costs of harmonizing policies as a consequence of the increased heterogeneity of individual preferences in an international union or in a country composed of at least two regions. This thesis stems from this strand of literature and aims to shed some light on two highly relevant aspects of the political economy of European integration. The first concerns the role of public opinion in the integration process; more precisely, how economic benefits and costs of integration shape citizens' support for European Union (EU) membership. The second is the allocation of policy competences among different levels of government: European, national and regional. Chapter 1 introduces the topics developed in this thesis by reviewing the main recent theoretical developments in the political economy analysis of integration processes. It is structured as follows. First, it briefly surveys a few relevant articles on economic theories of integration and disintegration processes (Alesina and Spolaore 1997, Bolton and Roland 1997, Alesina et al. 2000, Casella and Feinstein 2002) and discusses their relevance for the study of the impact of economic benefits and costs on public opinion attitude towards the EU. Subsequently, it explores the links existing between such political economy literature and theories of fiscal federalism, especially with regard to normative considerations concerning the optimal allocation of competences in a union. Chapter 2 firstly proposes a model of citizens’ support for membership of international unions, with explicit reference to the EU; subsequently it tests the model on a panel of EU countries. What are the factors that influence public opinion support for the European Union (EU)? In international relations theory, the idea that citizens' support for the EU depends on material benefits deriving from integration, i.e. whether European integration makes individuals economically better off (utilitarian support), has been common since the 1970s, but has never been the subject of a formal treatment (Hix 2005). A small number of studies in the 1990s have investigated econometrically the link between national economic performance and mass support for European integration (Eichenberg and Dalton 1993; Anderson and Kalthenthaler 1996), but only making informal assumptions. The main aim of Chapter 2 is thus to propose and test our model with a view to providing a more complete and theoretically grounded picture of public support for the EU. Following theories of utilitarian support, we assume that citizens are in favour of membership if they receive economic benefits from it. To develop this idea, we propose a simple political economic model drawing on the recent economic literature on integration and disintegration processes. The basic element is the existence of a trade-off between the benefits of centralisation and the costs of harmonising policies in presence of heterogeneous preferences among countries. The approach we follow is that of the recent literature on the political economy of international unions and the unification or break-up of nations (Bolton and Roland 1997, Alesina and Wacziarg 1999, Alesina et al. 2001, 2005a, to mention only the relevant). The general perspective is that unification provides returns to scale in the provision of public goods, but reduces each member state’s ability to determine its most favoured bundle of public goods. In the simple model presented in Chapter 2, support for membership of the union is increasing in the union’s average income and in the loss of efficiency stemming from being outside the union, and decreasing in a country’s average income, while increasing heterogeneity of preferences among countries points to a reduced scope of the union. Afterwards we empirically test the model with data on the EU; more precisely, we perform an econometric analysis employing a panel of member countries over time. The second part of Chapter 2 thus tries to answer the following question: does public opinion support for the EU really depend on economic factors? The findings are broadly consistent with our theoretical expectations: the conditions of the national economy, differences in income among member states and heterogeneity of preferences shape citizens’ attitude towards their country’s membership of the EU. Consequently, this analysis offers some interesting policy implications for the present debate about ratification of the European Constitution and, more generally, about how the EU could act in order to gain more support from the European public. Citizens in many member states are called to express their opinion in national referenda, which may well end up in rejection of the Constitution, as recently happened in France and the Netherlands, triggering a European-wide political crisis. These events show that nowadays understanding public attitude towards the EU is not only of academic interest, but has a strong relevance for policy-making too. Chapter 3 empirically investigates the link between European integration and regional autonomy in Italy. Over the last few decades, the double tendency towards supranationalism and regional autonomy, which has characterised some European States, has taken a very interesting form in this country, because Italy, besides being one of the founding members of the EU, also implemented a process of decentralisation during the 1970s, further strengthened by a constitutional reform in 2001. Moreover, the issue of the allocation of competences among the EU, the Member States and the regions is now especially topical. The process leading to the drafting of European Constitution (even if then it has not come into force) has attracted much attention from a constitutional political economy perspective both on a normative and positive point of view (Breuss and Eller 2004, Mueller 2005). The Italian parliament has recently passed a new thorough constitutional reform, still to be approved by citizens in a referendum, which includes, among other things, the so called “devolution”, i.e. granting the regions exclusive competence in public health care, education and local police. Following and extending the methodology proposed in a recent influential article by Alesina et al. (2005b), which only concentrated on the EU activity (treaties, legislation, and European Court of Justice’s rulings), we develop a set of quantitative indicators measuring the intensity of the legislative activity of the Italian State, the EU and the Italian regions from 1973 to 2005 in a large number of policy categories. By doing so, we seek to answer the following broad questions. Are European and regional legislations substitutes for state laws? To what extent are the competences attributed by the European treaties or the Italian Constitution actually exerted in the various policy areas? Is their exertion consistent with the normative recommendations from the economic literature about their optimum allocation among different levels of government? The main results show that, first, there seems to be a certain substitutability between EU and national legislations (even if not a very strong one), but not between regional and national ones. Second, the EU concentrates its legislative activity mainly in international trade and agriculture, whilst social policy is where the regions and the State (which is also the main actor in foreign policy) are more active. Third, at least two levels of government (in some cases all of them) are significantly involved in the legislative activity in many sectors, even where the rationale for that is, at best, very questionable, indicating that they actually share a larger number of policy tasks than that suggested by the economic theory. It appears therefore that an excessive number of competences are actually shared among different levels of government. From an economic perspective, it may well be recommended that some competences be shared, but only when the balance between scale or spillover effects and heterogeneity of preferences suggests so. When, on the contrary, too many levels of government are involved in a certain policy area, the distinction between their different responsibilities easily becomes unnecessarily blurred. This may not only leads to a slower and inefficient policy-making process, but also risks to make it too complicate to understand for citizens, who, on the contrary, should be able to know who is really responsible for a certain policy when they vote in national,local or European elections or in referenda on national or European constitutional issues.

Study on the regulation of mRNA expression of GABA transporters (GAT-1 and GAT-3) in rat brain

The submitted work concentrated on the study of mRNA expression of two distinct GABA transporters, GAT-1 and GAT-3, in the rat brain. For the detection and quantification of the chosen mRNAs, appropriate methods had to be established. Two methods, ribonuclease protection assay (RPA) and competitive RT-PCR were emloyed in the present study. Competitive RT-PCR worked out to be 20 times more sensitive as RPA. Unlike the sensitivity, the fidelity of both techniques was comparable with respect to their intra- and inter-assay variability.The basal mRNA levels of GAT-1 and GAT-3 were measured in various brain regions. Messenger RNAs for both transporters were detected in all tested brain regions. Depending on the region, the observed mRNA level for GAT-1 was 100-300 higher than for GAT-3. The GAT-1 mRNA levels were similar in all tested regions. The distribution of GAT-3 mRNA seemed to be more region specific. The strongest GAT-3 mRNA expression was detected in striatum, medulla oblongata and thalamus. The lowest levels of GAT-3 were in cortex frontalis and cerebellum.Furthermore, the mRNA expression for GAT-1 and GAT-3 was analysed under altered physiological conditions; in kindling model of epilepsy and also after long-term treatment drugs modulating GABAergic transmission. In kindling model of epilepsy, altered GABA transporter function was hypothesised by During and coworkers (During et al., 1995) after observed decrease in binding of nipecotic acid, a GAT ligand, in hippocampus of kindled animals. In the present work, the mRNA levels were measured in hippocampus and whole brain samples. Neither GAT-1 nor GAT-3 showed altered transcription in any tested region of kindled animals compared to controls. This leads to conclusion that an altered functionality of GABA transporters is involved in epilepsy rather than a change in their expression.The levels of GAT-1 and GAT-3 mRNAs were also measured in the brain of rats chronically treated with diazepam or zolpidem, GABAA receptor agonists. Prior to the molecular biology tests, behavioural analysis was carried out with chronically and acutely treated animals. In two tests, open field and elevated plus-maze, the basal activity exploration and anxiety-like behaviour were analysed. Zolpidem treatment increased exploratory activity. There were observed no differencies between chronically and acutely treated animals. Diazepam increased exploratory activity and decresed anxiety-like behaviour when applied acutely. This effect disappeard after chronic administration of diazepam. The loss of effect suggested a development of tolerance to effects of diazepam following long-term administration. Double treatment, acute injection of diazepam after chronic diazepam treatment, confirmed development of a tolerance to effects of diazepam. Also, the mRNAs for GAT-1 and GAT-3 were analysed in cortex frontalis, hippocampus, cerebellum and whole brain samples of chronically treated animals. The mRNA levels for any of tested GABA transporters did not show significant changes in any of tested region neither after diazepam nor zolpidem treatment. Therefore, changes in GAT-1 and GAT-3 transcription are probably not involved in adaptation of GABAergic system to long-term benzodiazepine administration and so in development of tolerance to benzodiazepines.

Synthesis and characterisation of photoreactive silanes for the self-assembly on functionalised silica surfaces

The aim of this thesis was to investigate novel techniques to create complex hierarchical chemical patterns on silica surfaces with micro to nanometer sized features. These surfaces were used for a site-selective assembly of colloidal particles and oligonucleotides. To do so, functionalised alkoxysilanes (commercial and synthesised ones) were deposited onto planar silica surfaces. The functional groups can form reversible attractive interactions with the complementary surface layers of the opposing objects that need to be assembled. These interactions determine the final location and density of the objects onto the surface. Photolithographically patterned silica surfaces were modified with commercial silanes, in order to create hydrophilic and hydrophobic regions on the surface. Assembly of hydrophobic silica particles onto these surfaces was investigated and finally, pH and charge effects on the colloidal assembly were analysed. In the second part of this thesis the concept of novel, "smart" alkoxysilanes is introduced that allows parallel surface activation and patterning in a one-step irradiation process. These novel species bear a photoreactive head-group in a protected form. Surface layers made from these molecules can be irradiated through a mask to remove the protecting group from selected regions and thus generate lateral chemical patterns of active and inert regions on the substrate. The synthesis of an azide-reactive alkoxysilane was successfully accomplished. Silanisation conditions were carefully optimised as to guarantee a smooth surface layer, without formation of micellar clusters. NMR and DLS experiments corroborated the absence of clusters when using neither water nor NaOH as catalysts during hydrolysis, but only the organic solvent itself. Upon irradiation of the azide layer, the resulting nitrene may undergo a variety of reactions depending on the irradiation conditions. Contact angle measurements demonstrated that the irradiated surfaces were more hydrophilic than the non-irradiated azide layer and therefore the formation of an amine upon irradiation was postulated. Successful photoactivation could be demonstrated using condensation patterns, which showed a change in wettability on the wafer surface upon irradiation. Colloidal deposition with COOH functionalised particles further underlined the formation of more hydrophilic species. Orthogonal photoreactive silanes are described in the third part of this thesis. The advantage of orthogonal photosensitive silanes is the possibility of having a coexistence of chemical functionalities homogeneously distributed in the same layer, by using appropriate protecting groups. For this purpose, a 3',5'-dimethoxybenzoin protected carboxylic acid silane was successfully synthesised and the kinetics of its hydrolysis and condensation in solution were analysed in order to optimise the silanisation conditions. This compound was used together with a nitroveratryl protected amino silane to obtain bicomponent surface layers. The optimum conditions for an orthogonal deprotection of surfaces modified with this two groups were determined. A 2-step deprotection process through a mask generated a complex pattern on the substrate by activating two different chemistries at different sites. This was demonstrated by colloidal adsorption and fluorescence labelling of the resulting substrates. Moreover, two different single stranded oligodeoxynucleotides were immobilised onto the two different activated areas and then hybrid captured with their respective complementary, fluorescent labelled strand. Selective hybridisation could be shown, although non-selective adsorption issues need to be resolved, making this technique attractive for possible DNA microarrays.