Element speciation and behaviour in metal-rich Boreal river and estuarine systems using ultrafiltration and chemical modelling

The bioavailability of metals and their potential for environmental pollution depends not simply on total concentrations, but is to a great extent determined by their chemical form. Consequently, knowledge of aqueous metal species is essential in investigating potential metal toxicity and mobility. The overall aim of this thesis is, thus, to determine the species of major and trace elements and the size distribution among the different forms (e.g. ions, molecules and mineral particles) in selected metal-enriched Boreal river and estuarine systems by utilising filtration techniques and geochemical modelling. On the basis of the spatial physicochemical patterns found, the fractionation and complexation processes of elements (mainly related to input of humic matter and pH-change) were examined. Dissolved (<1 kDa), colloidal (1 kDa-0.45 μm) and particulate (>0.45 μm) size fractions of sulfate, organic carbon (OC) and 44 metals/metalloids were investigated in the extremely acidic Vörå River system and its estuary in W Finland, and in four river systems in SW Finland (Sirppujoki, Laajoki, Mynäjoki and Paimionjoki), largely affected by soil erosion and acid sulfate (AS) soils. In addition, geochemical modelling was used to predict the formation of free ions and complexes in these investigated waters. One of the most important findings of this study is that the very large amounts of metals known to be released from AS soils (including Al, Ca, Cd, Co, Cu, Mg, Mn, Na, Ni, Si, U and the lanthanoids) occur and can prevail mainly in toxic forms throughout acidic river systems; as free ions and/or sulfate-complexes. This has serious effects on the biota and especially dissolved Al is expected to have acute effects on fish and other organisms, but also other potentially toxic dissolved elements (e.g. Cd, Cu, Mn and Ni) can have fatal effects on the biota in these environments. In upstream areas that are generally relatively forested (higher pH and contents of OC) fewer bioavailable elements (including Al, Cu, Ni and U) may be found due to complexation with the more abundantly occurring colloidal OC. In the rivers in SW Finland total metal concentrations were relatively high, but most of the elements occurred largely in a colloidal or particulate form and even elements expected to be very soluble (Ca, K, Mg, Na and Sr) occurred to a large extent in colloidal form. According to geochemical modelling, these patterns may only to a limited extent be explained by in-stream metal complexation/adsorption. Instead there were strong indications that the high metal concentrations and dominant solid fractions were largely caused by erosion of metal bearing phyllosilicates. A strong influence of AS soils, known to exist in the catchment, could be clearly distinguished in the Sirppujoki River as it had very high concentrations of a metal sequence typical of AS soils in a dissolved form (Ba, Br, Ca, Cd, Co, K, Mg, Mn, Na, Ni, Rb and Sr). In the Paimionjoki River, metal concentrations (including Ba, Cs, Fe, Hf, Pb, Rb, Si, Th, Ti, Tl and V; not typical of AS soils in the area) were high, but it was found that the main cause of this was erosion of metal bearing phyllosilicates and thus these metals occurred dominantly in less toxic colloidal and particulate fractions. In the two nearby rivers (Laajoki and Mynäjoki) there was influence of AS soils, but it was largely masked by eroded phyllosilicates. Consequently, rivers draining clay plains sensitive to erosion, like those in SW Finland, have generally high background metal concentrations due to erosion. Thus, relying on only semi-dissolved (<0.45 μm) concentrations obtained in routine monitoring, or geochemical modelling based on such data, can lead to a great overestimation of the water toxicity in this environment. The potentially toxic elements that are of concern in AS soil areas will ultimately be precipitated in the recipient estuary or sea, where the acidic metalrich river water will gradually be diluted/neutralised with brackish seawater. Along such a rising pH gradient Al, Cu and U will precipitate first together with organic matter closest to the river mouth. Manganese is relatively persistent in solution and, thus, precipitates further down the estuary as Mn oxides together with elements such as Ba, Cd, Co, Cu and Ni. Iron oxides, on the contrary, are not important scavengers of metals in the estuary, they are predicted to be associated only with As and PO4.

Manifestation of the pairing symmetry in the vortex core structure in iron-based superconductors

The superconducting gap is a basic character of a superconductor. While the cuprates and conventional phonon-mediated superconductors are characterized by distinct d- and s-wave pairing symmetries with nodal and nodeless gap distributions respectively, the superconducting gap distributions in iron-based superconductors are rather diversified. While nodeless gap distributions have been directly observed in Ba1–xKxFe2As2, BaFe2–xCoxAs2, LiFeAs, KxFe2–ySe2, and FeTe1–xSex, the signatures of a nodal superconducting gap have been reported in LaOFeP, LiFeP, FeSe, KFe2As2, BaFe2–xRuxAs2, and BaFe2(As1–xPx)2. Due to the multiplicity of the Fermi surface in these compounds s± and d pairing states can be both nodeless and nodal. A nontrivial orbital structure of the order parameter, in particular the presence of the gap nodes, leads to effects in which the disorder is much richer in dx2–y2-wave superconductors than in conventional materials. In contrast to the s-wave case, the Anderson theorem does not work, and nonmagnetic impurities exhibit a strong pair-breaking influence. In addition, a finite concentration of disorder produces a nonzero density of quasiparticle states at zero energy, which results in a considerable modification of the thermodynamic and transport properties at low temperatures. The influence of order parameter symmetry on the vortex core structure in iron-based pnictide and chalcogenide superconductors has been investigated in the framework of quasiclassical Eilenberger equations. The main results of the thesis are as follows. The vortex core characteristics, such as, cutoff parameter, ξh, and core size, ξ2, determined as the distance at which density of the vortex supercurrent reaches its maximum, are calculated in wide temperature, impurity scattering rate, and magnetic field ranges. The cutoff parameter, ξh(B; T; Г), determines the form factor of the flux-line lattice, which can be obtained in _SR, NMR, and SANS experiments. A comparison among the applied pairing symmetries is done. In contrast to s-wave systems, in dx2–y2-wave superconductors, ξh/ξc2 always increases with the scattering rate Г. Field dependence of the cutoff parameter affects strongly on the second moment of the magnetic field distributions, resulting in a significant difference with nonlocal London theory. It is found that normalized ξ2/ξc2(B/Bc2) dependence is increasing with pair-breaking impurity scattering (interband scattering for s±-wave and intraband impurity scattering for d-wave superconductors). Here, ξc2 is the Ginzburg-Landau coherence length determined from the upper critical field Bc2 = Φ0/2πξ2 c2, where Φ0 is a flux quantum. Two types of ξ2/ξc2 magnetic field dependences are obtained for s± superconductors. It has a minimum at low temperatures and small impurity scattering transforming in monotonously decreasing function at strong scattering and high temperatures. The second kind of this dependence has been also found for d-wave superconductors at intermediate and high temperatures. In contrast, impurity scattering results in decreasing of ξ2/ξc2(B/Bc2) dependence in s++ superconductors. A reasonable agreement between calculated ξh/ξc2 values and those obtained experimentally in nonstoichiometric BaFe2–xCoxAs2 (μSR) and stoichiometric LiFeAs (SANS) was found. The values of ξh/ξc2 are much less than one in case of the first compound and much more than one for the other compound. This is explained by different influence of two factors: the value of impurity scattering rate and pairing symmetry.

A field survey of crop management practices and distribution of ALS resistant Euphorbia heterophylla in two states in southern Brazil

Herbicide resistance was reported in Brazil almost ten years ago. One of the main weeds with herbicide resistance is wild poinsettia (Euphorbia heterophylla). This work evaluates the distribution of ALS-resistant E. heterophylla in two states in southern Brazil and determines the major contributing management causes for weed resistance selection in the area. E. heterophylla seeds from 148 sites located in Paraná and Rio Grande do Sul were sampled during 2001 and 2002. Farmers provided specific site data for weed control, tillage system, crop rotation and harvesting operations during previous years. ALS resistant E. heterophylla biotypes were found widely distributed in the survey area. Data analysis suggests seed dissemination is unlikely to explain the widespread distribution of resistance. The most probable factor for the selection of the resistant E. heterophylla is the persistent high use of ALS-inhibiting herbicides over time. Indirect evidence is presented demonstrating the need to educate legislators and farmers about the importance of herbicide mixtures as a strategy to prevent herbicide resistance.

SobekCM’s Community Ecosystems & Socio-Technical Practices

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Resonant tunneling effects in semiconductor heterostructures

The thesis is devoted to a theoretical study of resonant tunneling phenomena in semiconductor heterostructures and nanostructures. It considers several problems relevant to modern solid state physics. Namely these are tunneling between 2D electron layers with spin-orbit interaction, tunnel injection into molecular solid material, resonant tunnel coupling of a bound state with continuum and resonant indirect exchange interaction mediated by a remote conducting channel. A manifestation of spin-orbit interaction in the tunneling between two 2D electron layers is considered. General expression is obtained for the tunneling current with account of Rashba and Dresselhaus types of spin-orbit interaction and elastic scattering. It is demonstrated that the tunneling conductance is very sensitive to relation between Rashba and Dresselhaus contributions and opens possibility to determine the spin-orbit interaction parameters and electron quantum lifetime in direct tunneling experiments with no external magnetic field applied. A microscopic mechanism of hole injection from metallic electrode into organic molecular solid (OMS) in high electric field is proposed for the case when the molecules ionization energy exceeds work function of the metal. It is shown that the main contribution to the injection current comes from direct isoenergetic transitions from localized states in OMS to empty states in the metal. Strong dependence of the injection current on applied voltage originates from variation of the number of empty states available in the metal rather than from distortion of the interface barrier. A theory of tunnel coupling between an impurity bound state and the 2D delocalized states in the quantum well (QW) is developed. The problem is formulated in terms of Anderson-Fano model as configuration interaction between the carrier bound state at the impurity and the continuum of delocalized states in the QW. An effect of this interaction on the interband optical transitions in the QW is analyzed. The results are discussed regarding the series of experiments on the GaAs structures with a -Mn layer. A new mechanism of ferromagnetism in diluted magnetic semiconductor heterosructures is considered, namely the resonant enhancement of indirect exchange interaction between paramagnetic centers via a spatially separated conducting channel. The underlying physical model is similar to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction; however, an important difference relevant to the low-dimensional structures is a resonant hybridization of a bound state at the paramagnetic ion with the continuum of delocalized states in the conducting channel. An approach is developed, which unlike RKKY is not based on the perturbation theory and demonstrates that the resonant hybridization leads to a strong enhancement of the indirect exchange. This finding is discussed in the context of the known experimental data supporting the phenomenon.

Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+]

The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductance inhibition which took a few seconds to fully develop and was instantaneously released by pulse inversion to negative voltage, indicating a short-duration memory of the inhibiting factors. Sinusoidal stimulation at 23.4 mM [Cl-] showed hysteresis in the current versus voltage curves, even at very low frequency, suggesting that the rate of voltage application was also relevant for the inhibition/releasing effect to develop. We conclude that the voltage modulation of apical Cl- permeability is essentially a fast process and the apparent slow components of activation/deactivation obtained in the whole skin are a consequence of a gradual voltage build-up across the apical membrane due to voltage sharing between apical and basolateral membranes

Electro-oscillographic correlation between dorsal raphe nucleus, neocortex and hippocampus during wakefulness before and after serotoninergic inactivation

Theta rhythm in many brain structures characterizes wakefulness and desynchronized sleep in most subprimate mammalian brains. In close relation to behaviors, theta frequency and voltage undergo a fine modulation which may involve mobilization of dorsal raphe nucleus efferent pathways. In the present study we analyzed frequency modulation (through instantaneous frequency variation) of theta waves occurring in three cortical areas, in hippocampal CA1 and in the dorsal raphe nucleus of Wistar rats during normal wakefulness and after injection of the 5-HT1a receptor agonist 8-OH-DPAT into the dorsal raphe. We demonstrated that in attentive states the variation of theta frequency among the above structures is highly congruent, whereas after 8-OH-DPAT injection, although regular signals are present, the variation is much more complex and shows no relation to behaviors. Such functional uncoupling after blockade demonstrates the influence of dorsal raphe nucleus efferent serotoninergic fibers on the organization of alertness, as evaluated by electro-oscillographic analysis.

Participation of nitric oxide in the nucleus isthmi in CO2-drive to breathing in toads

The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain. It has been reported that NI plays an important role in integration of CO2 chemoreceptor information and glutamate is probably involved in this function. However, very little is known about the mechanisms involved. Recently, it has been shown that nitric oxide synthase (NOS) is expressed in the brain of the frog. Thus the gas nitric oxide (NO) may be involved in different functions in the brain of amphibians and may act as a neurotransmitter or neuromodulator. We tested the hypothesis that NO plays a role in CO2-drive to breathing, specifically in the NI comparing pulmonary ventilation, breathing frequency and tidal volume, after microinjecting 100 nmol/0.5 µl of L-NAME (a nonselective NO synthase inhibitor) into the NI of toads (Bufo paracnemis) exposed to normocapnia and hypercapnia. Control animals received microinjections of vehicle of the same volume. Under normocapnia no significant changes were observed between control and L-NAME-treated toads. Hypercapnia caused a significant (P<0.01) increase in ventilation only after intracerebral microinjection of L-NAME. Exposure to hypercapnia caused a significant increase in breathing frequency both in control and L-NAME-treated toads (P<0.01 for the control group and P<0.001 for the L-NAME group). The tidal volume of the L-NAME group tended to be higher than in the control group under hypercapnia, but the increase was not statistically significant. The data indicate that NO in the NI has an inhibitory effect only when the respiratory drive is high (hypercapnia), probably acting on tidal volume. The observations reported in the present investigation, together with other studies on the presence of NOS in amphibians, indicate a considerable degree of phylogenetic conservation of the NO pathway amongst vertebrates.

Characterization of a methionine-rich protein from the seeds of Cereus jamacaru Mill. (Cactaceae)

We describe here the isolation and characterization of a major albumin from the seeds of Cereus jamacaru (Cactaceae), to which we gave the trivial name of cactin. This protein has a molecular mass of 11.3 kDa and is formed by a light chain (3.67 kDa) and a heavy chain (7.63 kDa). This protein was isolated using a combination of gel filtration chromatography and reverse-phase HPLC. The amino acid composition of cactin was determined and found to resemble that of the 2S seed reserve protein from the Brazil nut, a protein remarkable for its high methionine content. The usefulness of cactin as a molecular marker in the taxonomy of the Cactaceae is discussed.

The compulsive-like aspect of the head dipping emission in rats with chronic electrolytic lesion in the area of the median raphe nucleus

Head dipping (HD) is a behavioral pattern considered to have a risk assessment or an exploratory role and is used as a complementary parameter to evaluate anxiety in experimental animals. Since rats with electrolytic lesion in the area of the median raphe nucleus displayed high frequencies of HD in a previous study, the present investigation was undertaken to confirm this observation and to determine its anxiety-related origin. HD episodes were counted in adult male Wistar rats (270-350 g) with electrolytic lesion (N = 11) and sham-lesioned controls (N = 12). When HD was measured for 60 min on an elevated open platform, lesioned rats emitted 13 times more HD than controls (264.7 ± 93.3 vs 20.3 ± 7.6 episodes), with the difference being statistically significant (P < 0.05). HD counts during 10-min sessions held 7, 14, 21, 27, and 63 days after lesion showed significantly higher means (range: 28.14 ± 5.38 to 62.85 ± 9.48) compared to sham-lesioned controls (range: 7.37 ± 1.13 to 8.5 ± 1.45). Normal rats stepped down into their home cages when the vertical distance between them and the cage was short (16 cm), and the step-down latencies increased with increasing depths (36.7 ± 7.92 to 185.87 ± 35.44 s). Lesioned rats showed a similar behavior when facing the shortest depth, but had a significantly increased number (23.28 ± 2.35 episodes) and latency (300 ± 0.00 s) of HD compared to normal rats (9.25 ± 1.37 episodes and 185.87 ± 35.44 s) when facing the greatest depth (30 cm). This suggests that HD may be a depth-measuring behavior related to risk assessment.

Differentiation of autonomic reflex control begins with cellular mechanisms at the first synapse within the nucleus tractus solitarius

Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central integration of these autonomic pathways. The visceral afferent synapse is uncommonly powerful at the NTS with large unitary response amplitudes and depression rather than facilitation at moderate to high frequencies of activation. Substantial signal depression occurs through multiple mechanisms at this very first brainstem synapse onto second order NTS neurons. This review highlights new approaches to the study of these basic processes featuring patch clamp recordings in NTS brain slices and optical techniques with fluorescent tracers. The vanilloid receptor agonist, capsaicin, distinguishes two classes of second order neurons (capsaicin sensitive or capsaicin resistant) that appear to reflect unmyelinated and myelinated afferent pathways. The differences in cellular properties of these two classes of NTS neurons indicate clear functional differentiation at both the pre- and postsynaptic portions of these first synapses. By virtue of their position at the earliest stage of these pathways, such mechanistic differences probably impart important differentiation in the performance over the entire reflex pathways.

Stabilization of partially folded states in protein folding/misfolding transitions by hydrostatic pressure

In the last few years, hydrostatic pressure has been extensively used in the study of both protein folding and misfolding/aggregation. Compared to other chemical or physical denaturing agents, a unique feature of pressure is its ability to induce subtle changes in protein conformation, which allow the stabilization of partially folded intermediate states that are usually not significantly populated under more drastic conditions (e.g., in the presence of chemical denaturants or at high temperatures). Much of the recent research in the field of protein folding has focused on the characterization of folding intermediates since these species appear to be involved in a variety of disease-causing protein misfolding and aggregation events. The exact mechanisms of these biologicalphenomena, however, are still poorly understood. Here, we review recent examples of the use of hydrostatic pressure as a tool to obtain insight into the forces and energetics governing the productive folding or the misfolding and aggregation of proteins.

Suomen mahdollisuudet vaikuttaa Euroopan unionin lainsäädäntömenettelyyn

Väitöstutkimuksen kohteena on säädösten valmistelu ja niitä koskevaa päätöksenteko Euroopan unionissa erityisesti siitä näkökulmasta, miten Suomen kaltainen pieni jäsenvaltio voi vaikuttaa EU-säädöksiin. Väitöskirjassa analysoidaan unionin toimielinten välillä vallitsevaa dynamiikkaa ja Suomen asemaa erityisesti EUT-sopimuksen 289 artiklan 1 kohdan ja 294 artiklan mukaisessa tavallisessa lainsäätämisjärjestyksessä. Lissabonin sopimuksen voimaantulon jälkeen tavallinen lainsäätämisjärjestys, joka aiemmin tunnettiin yhteispäätösmenettelynä, on selvästi yleisin lainsäädäntömenettely unionissa. Väitöskirja koostuu kuudesta erillisjulkaistusta pääosin vertaisarvioidusta artikkelista ja niitä täydentävästä ja kokoavasta yhteenveto-osasta. Kirjan tämä painos sisältää vain yhteenvetoluvun, ei erikseen julkaistuja artikkeleita. Väitöskirjassa hyödynnetään eurooppaoikeuden ja politiikan tutkimuksen kirjallisuutta. Metodologisesti väitöstutkimus edustaa empiiristä oikeustutkimusta, jossa yhdistyy lainopillinen analyysi ja empiiristen, tässä tapauksessa lähinnä laadullisten aineistojen analyysi. Yhteenvedossa on seurattu lainsäädäntömuutoksia ja oikeuskäytäntöä 10. huhtikuuta 2015 asti. Väitöskirjatutkimuksen kantavana teemana on oikeuden ja politiikan suhde EUlainsäätämisessä. Artikkeleita ja yhteenvetoa sitovat yhteen kaksi yleisen tason argumenttia. Ensiksi, EU:n lainsäädäntömenettelyä koskevat oikeussäännöt ja institutionalisoituneet käytännöt luovat kehikon toimielinten sisäiselle päätöksenteolle sekä niiden välisille poliittisluonteisille neuvotteluille, vaikkakaan sääntöihin ja käytäntöihin ei yleensä ole tarvetta nimenomaisesti vedota menettelyn kuluessa. Toiseksi, koska Suomen kaltaisen pienen jäsenvaltion muodollinen valta – siis äänimäärä neuvostossa – on hyvin rajallinen, suomalaisten ministerien ja virkamiesten tulisi hyödyntää erilaisia epävirallisia vaikuttamiskanavia, jos halutaan vahvistaa Suomen tosiasiallista vaikutusvaltaa menettelyssä. Unionin lainsäädäntötoiminta ei tyypillisesti ole rationaalisen mallin mukaan etenevää päätöksentekoa, vaan tempoilevaa ja vaikeasti ennakoitavaa kamppailua eri preferenssejä edustavien toimijoiden välillä. Väitöskirjan ensimmäisessä artikkelissa analysoidaan säädösvalmistelua ja lainsäätämismenettelyä unionissa vaihe vaiheelta. Johtopäätöksenä todetaan, että unioniin on syntynyt yhteispäätösmenettelyn, sittemmin tavallisen lainsäätämisjärjestyksen myötä uudenlainen lainsäätämiskulttuuri, jolle on leimallista tiiviit yhteydet komission, Euroopan parlamentin ja neuvoston välillä. Toimielimet ottavat nykyisin joustavasti huomioon toistensa kantoja menettelyn edetessä, mikä mahdollistaa sen, että valtaosa EU-säädöksistä voidaan hyväksyä jo ensimmäisessä käsittelyssä. Toisessa tutkimusartikkelissa analysoidaan komission asemaa unionin toimielinrakenteessa. Artikkelissa tarkastellaan komission aloiteoikeutta sekä komission puheenjohtajan ja sen jäsenten valintamenettelyjä siitä näkökulmasta, edistääkö komissio todella unionin yleistä etua itsenäisenä ja riippumattomana, kuten EU-sopimuksen 17 artiklassa edellytetään. Tiettyjen järjestelyjen myötä Euroopan parlamentin ja komission suhde on kehittynyt siihen suuntaan, että komissio toimii jossain määrin parlamentille vastuunalaisena hallituksena. Artikkelissa kritisoidaan, että kehitys ei välttämättä lähennä kansalaisia unionin toimielimiin ja että kehitys omiaan vaarantamaan komission aseman verrattain riippumattomana välittäjänä trilogeissa. Kolmas artikkeli sisältää tapaustutkimuksen kuluttajille myönnettäviä luottoja sääntelevän direktiivin (2008/48/EY) valmisteluvaiheista. Tapaustutkimus konkretisoi Suomen hallituksen edustajien tekemän EU-vaikuttamisen keinoja, vahvuuksia ja kehittämiskohteita. Artikkelissa todetaan, että Suomelle aivan keskeinen vaikuttamisresurssi ovat sellaiset virkamiehet, jotka hallitsevat niin käsiteltävän säädöshankkeen sisältökysymykset kuin unionin päätöksentekomenettelyt ja toimielinten institutionalisoituneet käytännöt. Artikkelissa tehdyt empiiriset havainnot jäsenvaltioiden välillä käydyistä neuvotteluista tukevat konstruktiivisen mallin perusoletuksia. Neljännessä artikkelissa, joka on laadittu yhteistyönä professori Tapio Raunion kanssa, analysoidaan unioniasioiden kansallista valmistelua ja tarkemmin ottaen sitä, miten Suomen neuvottelukannat muotoutuvat valtioneuvoston yhteensovittamisjärjestelmän ylimmällä tasolla EU-ministerivaliokunnassa. Artikkelissa todetaan laajan pöytäkirja-aineiston ja sitä täydentävän haastatteluaineiston pohjalta, että EUministerivaliokunnan asialistan laadinta on delegoitu kokonaisuudessaan asiantuntijavirkamiehille. Lisäksi asialistan muotoutumiseen vaikuttaa luonnollisesti unionin toimielinten, erityisesti Eurooppa-neuvoston agenda. Toisaalta, EU-ministerivaliokunnan kokouksissa ministerit yksin tekevät päätöksiä ja linjaavat Suomen EU-politiikkaa. Viidennessä artikkelissa selvitetään, miten olisi toimittava, jos pyritään siihen, että uusi tai muutettu EU-säädös vastaisi mahdollisimman pitkälti Suomen kansallisesti määriteltyä neuvottelukantaa. Tehokkainta on vaikuttaa aloiteoikeutta lainsäädäntömenettelyssä käyttävään komissioon, tarvittaessa myös virkahierarkian ylimmillä tasoilla, sekä tehdä yhteistyötä muiden jäsenvaltioiden kanssa, erityisesti puheenjohtajavaltion, tulevien puheenjohtajavaltioiden ja suurten jäsenvaltioiden kanssa. Mikäli käsittelyssä oleva EU-säädöshanke arvioidaan kansallisesti erityisen tärkeiksi tai ongelmalliseksi, tulisi vaikuttamistoimia laajentaa kattamaan myös Euroopan parlamentin avainhenkilöitä. Kuudennessa artikkelissa analysoidaan suomalaisen kansalaisyhteiskunnan ja etujärjestöjen vaikutusmahdollisuuksia EU-asioiden valmistelussa. Johtopäätöksenä todetaan, että muodollinen yhteensovittaminen EU-valmistelujaostojen laajan kokoonpanon kokouksissa ei ole sidosryhmille ensisijainen eikä tehokkain vaikuttamisen keino. Sen sijaan korostuvat epäviralliset yhteydet toimivaltaisen ministeriön vastuuvirkamieheen kotimaassa ja vaikuttaminen eurooppalaisen kattojärjestön välityksellä. Väitöskirjan yhteenveto-osassa on eritelty, missä EU:n säädösvalmistelun ja lainsäätämismenettelyn vaiheissa Suomen kaltaisella pienellä jäsenvaltiolla on parhaat edellytykset vaikuttaa valmisteltavana olevaan säädökseen. Parhaat vaikutusmahdollisuudet ovat aivan EU-säädöksen elinkaaren alkuvaiheessa, kun komissio on vasta käynnistämässä uutta säädösvalmistelua. Väitöstutkimuksessa todetaan, että varhaista kannanmuodostusta ja sen mahdollistamaa ennakkovaikuttamista on Suomessa kyetty kehittämään etenkin niissä poliittisesti, taloudellisesti tai oikeudellisesti tärkeissä hankkeissa, joissa hallituksen kannanmuodostus tapahtuu EU-ministerivaliokunnassa. Muissa unionin säädöshankkeissa ennakollisen vaikuttamisen intensiteetti näyttäisi vaihtelevan, riippuen muun muassa toimivaltaisen ministeriön keskijohdon ja ylimmän johdon sitoutumisesta. Toinen Suomelle otollinen vaikuttamisen ajankohta on silloin, kun komission antamaa ehdotusta käsitellään asiantuntijavirkamiesten kesken neuvoston työryhmässä. Tehokas vaikuttaminen edellyttää, että Suomea neuvotteluissa edustavat henkilöt kokoavat ”samanmielisistä” jäsenvaltioista kaksoisenemmistösäännön mukaisen voittavan koalition. Viimeinen vaikuttamisen ikkuna aukeaa silloin, kun Coreper-komiteassa laaditaan neuvoston puheenjohtajalle neuvottelumandaattia toimielinten välisiin trilogeihin tavallisen lainsäätämisjärjestyksen ensimmäisessä käsittelyssä. Tässä varsin myöhäisessä menettelyvaiheessa vaikuttaminen on pienen jäsenvaltion näkökulmasta jo selvästi vaikeampaa. Väitöskirja sijoittuu luontevasti osaksi valtiotieteellistä eurooppalaistumis-kirjallisuutta siltä osin, kuin siinä on tutkittu EU-jäsenyyden vaikutuksia kotimaisiin hallinnon rakenteisiin ja politiikan asialistaan. Kuten tunnettua, Suomen EU-politiikka rakentuu eduskunnalle vastuullisen valtioneuvoston varaan. Väitöskirjassa ei kuitenkaan ole otettu erityiseen tarkasteluun perustuslakiin sidottua eduskunnan ja hallituksen yhteistoimintaa EU-asioissa. Sen sijaan on tutkittu unioniasioiden valmistelua ja yhteensovittamista valtioneuvoston sisällä. Kun EU-asioiden yhteensovittamisjärjestelmää luotiin, pidettiin tärkeänä, että jokaisessa säädöshankkeessa ja politiikkahankkeessa kyetään muodostamaan kansallisesti yksi ja yhtenäinen neuvottelupositio. Yhtenäisen kansallisen linjan ajamisen katsottiin parantavan Suomen asemaa unionin päätöksenteossa. Väitöskirjassa todetaan johtopäätöksenä, että EU-asioiden kansallinen valmistelujärjestelmä toteuttaa sille asetetut tavoitteet käytännössä varsin hyvin. Merkittävin kehittämiskohde liittyy kansallisen EU-valmistelun reaktiivisuuteen. Jos Suomi haluaa vaikuttaa yhä vahvemmin EU-lainsäätämiseen, Suomelle tärkeät hankkeet pitäisi tunnistaa jo varhaisessa vaiheessa ja priorisoida selkeästi niiden hoitamista ministeriöissä.

Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity

Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the experimental models used in research involve rodents, which are at least one order of magnitude smaller in linear dimensions than man. Consequently, images of targets obtained with conventional gamma-cameras and collimators have poor spatial resolution and statistical quality. We review the methodological approaches developed in recent years in order to obtain images of small targets with good spatial resolution and sensitivity. Multipinhole, coded mask- and slit-based collimators are presented as alternative approaches to improve image quality. In combination with appropriate decoding algorithms, these collimators permit a significant reduction of the time needed to register the projections used to make 3-D representations of the volumetric distribution of target’s radiotracers. Simultaneously, they can be used to minimize artifacts and blurring arising when single pinhole collimators are used. Representation images are presented, which illustrate the use of these collimators. We also comment on the use of coded masks to attain tomographic resolution with a single projection, as discussed by some investigators since their introduction to obtain near-field images. We conclude this review by showing that the use of appropriate hardware and software tools adapted to conventional gamma-cameras can be of great help in obtaining relevant functional information in experiments using small animals.

Paradoxical effect of a pequi oil-rich diet on the development of atherosclerosis: balance between antioxidant and hyperlipidemic properties

Pequi is the fruit of Caryocar brasiliense and its oil has a high concentration of monounsaturated and saturated fatty acids, which are anti- and pro-atherogenic agents, respectively, and of carotenoids, which give it antioxidant properties. Our objective was to study the effect of the intake of a cholesterol-rich diet supplemented with pequi oil, compared to the same diet containing soybean oil, on atherosclerosis development, and oxidative stress in atherosclerosis-susceptible LDL receptor-deficient mice (LDLr-/-, C57BL/6-background). Female mice were fed a cholesterol-rich diet containing 7% soybean oil (Soybean group, N = 12) or 7% pequi oil (Pequi group, N = 12) for 6 weeks. The Pequi group presented a more atherogenic lipid profile and more advanced atherosclerotic lesions in the aortic root compared to the Soybean group. However, the Pequi group presented a less advanced lesion in the aorta than the Soybean group and showed lower lipid peroxidation (Soybean group: 50.2 ± 7.1; Pequi group: 30.0 ± 4.8 µmol MDA/mg protein) and anti-oxidized LDL autoantibodies (Soybean group: 35.7 ± 9.4; Pequi group: 15.6 ± 3.7 arbitrary units). Peritoneal macrophages from the Pequi group stimulated with zymosan showed a reduction in the release of reactive oxygen species compared to the Soybean group. Our data suggest that a pequi oil-rich diet slows atherogenesis in the initial stages, possibly due to its antioxidant activity. However, the increase of serum cholesterol induces a more prominent LDL migration toward the intimae of arteries, increasing the advanced atherosclerotic plaque. In conclusion, pequi oil associated with an atherogenic diet worsens the lipid profile and accelerates the formation of advanced atherosclerotic lesions despite its antioxidant action.