Assessment techniques, database design and software facilities for thermodynamics and diffusion

The purpose of this article is to give a set of recommendations to producers of assessed thermodynamic data, who may be involved in either the critical evaluation of limited chemical systems or the creation and dissemination of larger thermodynamic databases. Also, it is hoped that reviewers and editors of scientific publications in this field will find some of the information useful. Good practice in the assessment process is essential, particularly as datasets from many different sources may be combined together into a single database. With this in mind, we highlight some problems that can arise during the assessment process and we propose a quality assurance procedure. It is worth mentioning at this point, that the provision of reliable assessed thermodynamic data relies heavily on the availability of high quality experimental information. The different software packages for thermodynamics and diffusion are described here only briefly

Aspects institutionnels de l'Association européenne de libre-échange

Detter de Lupis Ingrid. Aspects institutionnels de l'Association européenne de libre-échange. In: Annuaire français de droit international, volume 6, 1960. pp. 791-800

NMDA receptors play an anti-aggregating role in human platelets

Receptors for different monoamines, peptides and other neurohormones are present in the plasma membrane of platelets, and the sophisticated process of haemostasis is regulated by the interplay of their physiologic agonists (1). The recent report of a platelet binding site for phencyclidine (2) suggested a possible role of N-methyl-D-aspartate (NMDA) receptors in platelet function. Isotherms of [3H]-glutamate (GLU), [3H]-CGP-39653, [3H]-glycine (GLY) and [3H]-MK-801 carried out in platelet membranes yielded Bmax and Kd values for these ligands similar to those present in neurons, and NMDA only partially displaced [3H]-GLU. In neurons [3H]-MK-801 binding is potentiated by GLU and/or GLY and, being specific for the open NMDA receptor channel species, it has a functional meaning. In platelet membranes neither GLU and/or GLY increased [3H]-MK-801 binding; thus suggesting that NMDA receptors in platelets are different from those present in neurons. GLU or NMDA alone did not induce platelet aggregation. However, both amino acids were antagonistic on the aggregating activity of arachidonic acid (AA), NMDA being 3 orders of magnitude more active than GLU, and NMDA also antagonized adenosine diphosphate (ADP) and platelet aggregating factor (PAF) induced platelet aggregation. Finally, NMDA increased cAMP levels in intact platelets, and such an effect did not occur in a Ca(2+)-free medium; yet, cAMP increase was not antagonized by the calmodulin inhibitor trifluoperazine (TFP). It was concluded that platelet membranes carry an NMDA receptor, functionally distinct from the neuronal one, which seems to play an anti-aggregating role

Biologia evolutiva do desenvolvimento de artropodes: uma visão brasileira

Os artrópodes possuem o maior número de espécies dentro do reino animal e possuem também uma grande variabilidade morfológica. No Brasil, nosso grupo tem focado em estudar o desenvolvimento embrionário de organismos pertencentes ao filo Arthropoda, particularmente de organismos vetores de doenças ou causadores de grandes prejuízos econômicos, como as pragas de estocagem. Estes estudos têm revelado similaridades e diferenças na biologia do desenvolvimento dos artrópodes. Entre os estágios embrionários conservados encontra-se a banda germinal, que é bastante similar para todo o grupo (estágio filotípico), enquanto que os estágios iniciais, sob influência maternal e os estágios finais da embriogênese, são mais distintos. Estes resultados, junto com demais resultados da literatura, evidenciam uma história evolutiva comum e a constituição de um grupo monofilético dentre os artrópodes. Com o desenvolvimento de novas tecnologias e o surgimento da Biologia Evolutiva do Desenvolvimento (EVO-DEVO), tem sido possível investigar o controle morfogenético do desenvolvimento embrionário e pós-embrionário, comparando grupos taxonômicos distintos. No presente trabalho discutiremos a importância de ter outros organismos modelo além da mosca-da-fruta (Drosophila melanogaster) para estudos de biologia do desenvolvimento de artrópodes. Estes estudos incluem espécies de interesse médico como o hemiptera Rhodnius prolixus e o carrapato Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) bem como pragas de estocagem, o besouro Tribolium castaneum (Coleoptera)