Factors affecting Hg (II) adsorption in soils from the Rio Negro basin (Amazon)

Mercury (II) adsorption studies in top soils (top 10 cm) from the Rio Negro basin show this process depends strongly on some selected parameters of the aqueous phase in contact with the soils. Maximum adsorption occurred in the pH range 3.0-5.0 (>90%). Dissolved organic matter shows an inhibitory effect on the availability of Hg (II) to be adsorbed by the soils, whereas a higher chloride content of the solution resulted in a lower adsorption of Hg (II) at pH 5.0. Soils with higher organic matter content were less affected by changes in the salinity. An increase in the initial Hg (II) concentration increased the amount of Hg (II) adsorbed by the soil and decreased the time needed to reach equilibrium. A Freundlich isotherm provided a good model for Hg (II) adsorption in the two types of soil studied. The kinetics of Hg (II) adsorption on Amazonian soils showed to be very fast and followed pseudo-second order kinetics. An environmental implication of these results is discussed under the real scenario present in the Negro River basin, where acidic waters are in contact with a soil naturally rich in mercury.

The natural hallucinogen 5-MeO-DMT, component of Ayahuasca, disrupts cortical function in rats: reversal by antipsychotic drugs

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen component of Ayahuasca, an Amazonian beverage traditionally used for ritual, religious and healing purposes that is being increasingly used for recreational purposes in US and Europe. 5MeO-DMT is of potential interest for schizophrenia research owing to its hallucinogenic properties. Two other psychotomimetic agents, phencyclidine and 2,5-dimethoxy-4-iodo-phenylisopropylamine (DOI), markedly disrupt neuronal activity and reduce the power of low frequency cortical oscillations (<4 Hz, LFCO) in rodent medial prefrontal cortex (mPFC). Here we examined the effect of 5-MeO-DMT on cortical function and its potential reversal by antipsychotic drugs. Moreover, regional brain activity was assessed by blood-oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). 5-MeO-DMT disrupted mPFC activity, increasing and decreasing the discharge of 51 and 35% of the recorded pyramidal neurons, and reducing (−31%) the power of LFCO. The latter effect depended on 5-HT1A and 5-HT2A receptor activation and was reversed by haloperidol, clozapine, risperidone, and the mGlu2/3 agonist LY379268. Likewise, 5-MeO-DMT decreased BOLD responses in visual cortex (V1) and mPFC. The disruption of cortical activity induced by 5-MeO-DMT resembles that produced by phencyclidine and DOI. This, together with the reversal by antipsychotic drugs, suggests that the observed cortical alterations are related to the psychotomimetic action of 5-MeO-DMT. Overall, the present model may help to understand the neurobiological basis of hallucinations and to identify new targets in antipsychotic drug development.

Elektroniikkateollisuuden sopimusvalmistajana toimivan pk-yrityksen kasvustrategiat

Tutkielman tavoitteena oli selvittää, kuinka muutosvaiheessa oleva elektroniikkateollisuuden ala vaikuttaa siinä mukana olevien pienten ja keskisuurten sopimusvalmistaja yritysten tulevaisuuden kasvustrategioihin Tutkielmassa päädyttiin tarkastelemaan seuraavia kasvustrategioita: markkinapenetraatio, tuotekehitys yhdessä asiakkaan kanssa, markkinakehitys ja diversifikaatio. Tutkielmassa määriteltiin myös kasvustrategioihin yleisesti vaikuttavat tekijät, joita käsiteltiin empiriassa pk-sopimusvalmistajan näkökulmasta. Esitettyjä kasvustrategioita peilattiin elektroniikkateollisuuden tulevaisuuden näkymiin skenaariotyöskentelyä hyödyntäen. Erityisesti yrityksen sopimusvalmistajaroolin todettiin vaikuttavan niin kasvustrategioihin kuin valittua strategiaa toteuttaviin kasvukeinoihin. Tutkimuksessa käytettiin laadullista eli kvalitatiivista tutkimusotetta. Tutkimusmenetelmäksi puolestaan valittiin tapaus eli case-tutkimus. Kohdeyrityksen avulla pyrittiin luomaan syvempää ymmärrystä pk-sopimusvalmistajan resursseista, kyvykkyyksistä ja haasteista.