Molecular Dynamics Simulations for Metallic Nanosystems

Nanotechnology is a crucial field for future scientific development where many different disciplines meet. Computational modelization of nanometer-sized structures is a key issue in this development because (i) it allows a considerable saving of resources and costly experimental setups intended to fabricate nanometric test devices and (ii) nowadays the study of nanometric sized systems is feasible with thoroughly designed computational codes and relatively low cost computational resources. This article describes how molecular dynamics simulations, in combination with potentials obtained in the framework of the embedded atom method, are able to describe the properties of two systems of interest for the development of future nanoelectronic devices: metallic nanowires and metallic nanofilms. Our results show that nanowire stretching results in a series of well-defined geometric structures (shells) and that thin films experiment a crystallographic phase transition for a decreasing number of layers. In both cases, good agreement with experiments is found.     

RP-HPLC-fluorescence analysis of aliphatic aldehydes: application to aldehyde-generating enzymes HACL1 and SGPL1

Long-chain aldehydes are commonly produced in various processes, such as peroxisomal α-oxidation of long-chain 3-methyl-branched and 2-hydroxy fatty acids and microsomal breakdown of phosphorylated sphingoid bases. The enzymes involved in the aldehyde-generating steps of these processes are 2-hydroxyacyl-CoA lyase (HACL1) and sphingosine-1-phosphate lyase (SGPL1), respectively. In the present work, nonradioactive assays for these enzymes were developed employing the Hantzsch reaction. Tridecanal (C13-al) and heptadecanal (C17-al) were selected as model compounds and cyclohexane-1,3-dione as 1,3-diketone, and the fluorescent derivatives were analyzed by reversed phase (RP)-HPLC. Assay mixture composition, as well as pH and heating, were optimized for C13-al and C17-al. Under optimized conditions, these aldehydes could be quantified in picomolar range and different long-chain aldehyde derivatives were well resolved with a linear gradient elution by RP-HPLC. Aldehydes generated by recombinant enzymes could easily be detected via this method. Moreover, the assay allowed to document activity or deficiency in tissue homogenates and fibroblast lysates without an extraction step. In conclusion, a simple, quick, and cheap assay for the study of HACL1 and SGPL1 activities was developed, without relying on expensive mass spectrometric detectors or radioactive substrates.     

Cerebrospinal fluid miRNA profile in HIV‐encephalitis

MicroRNAs are short non‐coding RNAs that modulate gene expression by translational repression. Because of their high stability in intracellular as well as extracellular environments, miRNAs have recently emerged as important biomarkers in several human diseases. However, they have not been tested in the cerebrospinal fluid (CSF) of HIV‐1 positive individuals. Here, we present results of a study aimed at determining the feasibility of detecting miRNAs in the CSF of HIV‐infected individuals with and without encephalitis (HIVE). We also evaluated similarities and differences between CSF and brain tissue miRNAs in the same clinical setting. We utilized a high throughput approach of miRNA detection arrays and identified differentially expressed miRNAs in the frontal cortex of three cases each of HIV+, HIVE, and HIV? controls, and CSF of 10 HIV‐positive and 10 HIV‐negative individuals. For the CSF samples, the group of HIV+ individuals contained nine cases of HIV‐associated neurological disorders (HAND) and, among those, four had HIVE. All the HIV‐negative samples had non‐viral acute disseminate encephalomyelitis. A total of 66 miRNAs were found differentially regulated in HIV+ compared to HIV? groups. The greatest difference in miRNA expression was observed when four cases of HIVE were compared to five non‐HIVE cases, previously normalized with the HIV‐negative group. After statistical analyses, 11 miRNAs were fund significantly up‐regulated in HIVE. Although more clinical samples should be examined, this work represents the first report of CSF miRNAs in HIV‐infection and offers the basis for future investigation. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.     

Zooplankton and the North Atlantic Oscillation: a basin-scale analysis

This study examines multiple, long-term zooplankton time seriesacross the Atlantic region and its inland seas. Across a broadrange of geographic regions and ecological environments, theimpact of the North Atlantic Oscillation (NAO) on interannualchanges in the zooplankton populations was evident. Across themid-Atlantic, a correlation between the NAO and zooplanktonabundance was present and remained positive from the northwesternAtlantic through the enclosed seas of the far eastern Atlantic.Following high NAO years, these regions experienced higher totalzooplankton abundance or biomass. Following low NAO years, thistrend was reversed. A time lag in the zooplankton response tothe NAO was also evident, influenced more by the scale of thewater basin than by latitudinal or longitudinal location. Forsome regions, the correlation between zooplankton and the NAOwas higher when the NAO was substituted with its sub-components:the Azores High (AH) and the Icelandic Low (IL) atmosphericpressure systems. This suggests that decomposition of the NAOinto its components might enhance the sensitivity of the analysisof biological time series with regard to climate change.     

‘Generation Nemo’: motivations,satisfaction and career goals of marine biology students*

Marine biology is an increasingly preferred study major and career among youth. This is particularly the case of countries with extensive coastlines, such as Italy. In order to understand what exactly is fuelling this trend, and whether it culminates in the successful absorption of marine biologists as valued workforce by society, this study investigated the motivations, satisfaction and career goals of marine biology undergraduate students in Italy. Although it was expected that scientific literacy in formal education plays an important role in motivating marine biology students, the results showed that intrinsic motivations and informal education play a more crucial role. The students consider realistic career options, although these imply having to leave the country. The results of this study were used to make recommendations on the importance of marine and ocean literacy in the formal educational system in Italy, and the general improvement of scientific literacy in formal school education. Recommendations were also made on the potential improvements that can be made by higher education institutions, to better equip marine biologists with the skills required by emerging sectors in society. Finally, considerations were made regarding the dimensioning of supply, offer and marketing of employment opportunities for marine biologists in Italy.