Production of Antibacterial Compounds from Actinomycetes

Actinomycetes are soil-dwelling Gram-positive bacteria, industrially relevant as producers of a wide range of bioactive secondary metabolites, including many antibiotics of clinical and commercial importance

LA SCUOLA SPAIS: RICERCA SCIENTIFICA E DIDATTICA DELLE SCIENZE IN UN CONTESTO MULTIDISCIPLINARE

SPAIS si pone come obiettivo l’individuazione e il conseguente approfondimento delle conoscenze di base che sono necessarie nel campo della chimica, della fisica e delle scienze biologiche e naturali per comprendere e comunicare i contenuti fondamentali della moderna ricerca scientifica e tecnologica. L’edizione 2013 sul tema “ScientificaMente – le Neuroscienze” viene qui presentata evidenziandone particolarmente le implicazioni nella didattica della Chimic

VERSO UN APPRENDIMENTO AUTENTICO DELLA CHIMICA DI BASE: TRASPOSIZIONE DIDATTICA DEI RISULTATI DELLA MODERNA RICERCA SCIENTIFICA.

In questo lavoro viene presentata una proposta riguardante l'uso dei risultati della moderna ricerca in campo chimico per introdurre i concetti fondanti della disciplina nella pratica didattica della Chimica di base nella Scuola Secondaria di Secondo Grado. Con questo approccio, i concetti di base dovrebbero risultare meno astratti e il mondo della ricerca più accessibile

Scienza e Arti Perdute: i Segreti degli Antichi Maestri Liutai

Lo scopo di questo lavoro è illustrare agli insegnanti la connessione tra due settori di attività apparentemente lontani: la scelta dei materiali utilizzati nella liuteria artigianale e la chimica. Il ruolo, la composizione e la classificazione delle principali vernici per liuteria sono qui descritte assieme ad una breve sintesi dello stato dell’arte. Nel lavoro, vengono presentati i principali concetti di una tecnica analitica non distruttiva abbastanza semplice (la spettroscopia di fluorescenza da raggi X) ma, probabilmente, non abbastanza nota ai non addetti ai lavori. Un caso di studio a essa correlato è inoltre presentato per evidenziare uno dei possibili contributi del chimico nello studio dei beni culturali.The aim of this paper is showing teachers the connection between two apparently distant working fields: the choice of materials used in artisanal lute making and chemistry. The role, the composition and the classification of the main varnishes for classical lute making are here described with a brief review of the state of the art. Furthermore, the main theoretical basis of a relatively simple non-destructive analytical technique (X-Ray Fluorescence Spectroscopy), probably not very well known by non-specialists, is here illustrated. A case study is also presented to highlight one of the possible roles of the chemist in the study of cultural heritage

Polymer-coated Nanolimes Dispersions for Reduction, Deacidification and Consolidation of Ancient Paper

Nanolimes have been widely explored as nanomaterial for cultural heritage preservation. In particular, they have shown interesting properties to contrast the ageing of manuscripts, books and artistic works, opening up the possibility to store such items in a good quality state for longer. In the present work we reported an innovative nanolime-based formulation for paper restoration, which includes in its composition a reducing agent and a fibers consolidator as well. To formulate an efficient product, we deeply investigated the cellulose oxidation process with a multi-technique approach. The here presented formulation consists in a hydroalcoholic ternary dispersion of nanolimes coated with hydroxypropyl methylcellulose (HPMC) and tert- butylamine borane complex (TBAB) as cellulose fibers consolidator and reducer, respectively. The effectiveness of the ternary mixture has been demonstrated on oxidized paper, whose chemical and mechanical properties were partially recovered after the treatment

Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

A series of new gemini surfactants without a spacer group, disodium 2,3-dialkyl-1,2,3,4-butanetetracarboxylates, were synthesized in a green chemistry context minimizing the use of organic solvents and applying microwaves (MW) when activation energy was required. Once the desired architecture was confirmed by means of the nuclear magnetic resonance technique (1H-NMR, 1H-1H COSY) for all the studied surfactants, the critical micellization concentration was determined by conductance measurements. The diffusion coefficient of micelles formed by the four compounds was characterized using pulsed field gradient (PFG)-NMR. Diffusion coefficients were found to be dependent on the concentration and on the number of carbon atoms in the alkyl chain. The absence of the spacer group, peculiar to this new series of gemini surfactants, may confer relatively low flexibility to the molecules, with potential implications on the interfacial properties, namely on micellization. These gemini surfactants might have interesting applications in the preparation of composite materials, in nanotechnology, in gene transfection and mainly, due to the low CMCs, as new interesting ingredients of cosmetics and toiletries

Influence of temperature on calcium hydroxyapatite nanopowders

The aim of this work is to investigate the effects of thermal treatment, in the range of temperature between 80°C - 900°C, on crystallinity, morphology and particles size of calcium hydroxylapatite nanopowders (HAp). A complete study was carried out applying 31P Magic Angle Spinning NMR, X-ray diffraction, nitrogen porosimetry and Transmis- sion Electron Microscopy techniques. HAp specimens were prepared by chemical precipitation in an aqueous solution of calcium nitrate and ammonium hydrogen phosphate. The thermal treatment performed, showed the formation of crystals whose appearance has three main morphologies and different particles size. HAp treated up to 500°C showed a set of needle-like shape crystals with a low surface area value. These crystals turned into rod-like crystals with tem- perature increase, along with an increase in crystallite size. At 900°C was detected a hexagonal hydroxylapatite phase. Furthermore, Dynamic Light Scattering explored a stable HAp dispersion. The isopropyl alcohol dispersion resulted stable for at least two weeks, useful to create layers of determined morphology nanoparticles

Influence of the modification, induced by zirconia nanoparticles, on the structure and properties of polycarbonate

Melt compounding was used to prepare polycarbonate (PC)-zirconia nanocomposites with different amounts of zirconia. The effect of the zirconia loading, in the range of 1-5 wt.%, on the structure, mechanical properties and thermal degradation kinetics was investigated. The zirconia nanoparticle aggregates were well dispersed in the PC matrix and induced the appearance of a local lamellar order in the polycarbonate as inferred by SAXS findings. This order could be a consequence of the intermolecular interactions between zirconia and the polymer, in particular with the quaternary carbon bonded to the methyl groups and the methyl carbon as inferred from the NMR results. The presence of zirconia caused a decrease in the storage and loss moduli below the glass transition temperature. However, the highest amount of zirconia increased the modulus. The presence of zirconia in PC slightly increased the thermal stability, except for the highest zirconia content which showed a decrease. The activation energies of thermal degradation for the nanocomposites were significantly lower than that for pure PC at all degrees of conversion

Determination of Selected Polyaromatic Hydrocarbons by Gas Chromatography-Mass Spectrometry for the Analysis of Wood to Establish the cause of Sinking of an Old Vessel (Scauri wreck) by Fire

The aimof this paper was to establish the cause of sinking of an old wooden vessel by polycyclic aromatic hydrocarbon (PAH) analyses because wood combustion is a source of PAHs. In particular, the molecular PAH patterns generated by each source are like fingerprints and it is possible to determine the processes that generate PAHs by studying their distribution in wood samples. The relative abundance of high molecular weight PAHs, together with the PAH compound ratios and with total index (proposed by us) has demonstrated that samples owe their PAHs in wood archaeological material to a predominant single mode of origin, i.e. combustion processes, therefore we can say that the sinking of the vessel was caused by a fire