Design strategies for water-soluble small molecular chromogenic and fluorogenic probes.

Recent development of polymer electrolyte membranes for fuel cells.

Advances in the chemistry of tetrahydroquinolines.

This critical review is focused on examples reported in the year 2009 dealing with the design of chromogenic and fluorogenic chemosensors or reagents for anions (264 references).

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Chromogenic and fluorogenic chemosensors and reagents for anions. A comprehensive review of the years 2010-2011.

Priming applied to commercial seed lots is widely used by seed technologists to enhance seed vigour in terms of germination potential and increased stress tolerance. Priming can be also valuable to seed bank operators who need improved protocols of ex situ conservation of germplasm collections (crop and native species). Depending on plant species, seed morphology and physiology, different priming treatments can be applied, all of them triggering the so-called ‘pre-germinative metabolism’. This physiological process takes place during early seed imbibition and includes the seed repair response (activation of DNA repair pathways and antioxidant mechanisms), essential to preserve genome integrity, ensuring proper germination and seedling development. The review provides an overview of priming technology, describing the range of physical–chemical and biological treatments currently available. Optimised priming protocols can be designed using the ‘hydrotime concept’ analysis which provides the theoretical bases for assessing the relationship between water potential and germination rate. Despite the efforts so far reported to further improve seed priming, novel ideas and cutting-edge investigations need to be brought into this technological sector of agri-seed industry. Multidisciplinary translational research combining digital, bioinformatic and molecular tools will significantly contribute to expand the range of priming applications to other relevant commercial sectors, e.g. the native seed market.

Seed priming: state of the art and new perspectives.

Understanding the molecular pathways associated with seed vigor

This work presents a systematic study of cellulose (CLS) as a sacrificial biomass for photocatalytic H2 evolution from water. The idea is indeed to couple a largely available and not expensive biomass, and water, with a renewable energy like solar radiation. An aqueous CLS suspension irradiated either at 366 nm (UV-A) or under sunlight in the presence of Pt/TiO2 behaves as a H2 evolving system. The effects of irradiation time, catalyst and CLS concentrations, pH and water salinity are studied. Addition of CLS to the sample significantly improved H2 evolution from water splitting, with yields up to ten fold higher than those observed in neat water. The mechanism of the photocatalytic process relies on the TiO2-mediated CLS hydrolysis, under irradiation. The polysaccharide depolymerisation generates water-soluble species and intermediates, among them 5-hydroxymethylfurfural (HMF) was identified. These intermediates are readily oxidized following the glucose photoreforming, thus enhancing water hydrogen ion reduction to give gas-phase H2. The formation of “colored” by-products from HMF self-polymerization involves a sort of “in situ dye sensitization” that allows an effective photoreaction even under solar light. The procedure is evaluated and successfully extended on cellulosic biomasses, i.e. rice husk and alfalfa (Medicago sativa) stems, not previously investigated for this application.

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Sunlight-promoted photocatalytic hydrogen gas evolution from water-suspended cellulose: a systematic study

The dimetallic cryptate [Cu2II(1)]4+ selectively recognizes guanosine monophosphate with respect to other nucleoside monophospates (NMPs) in a MeOH/water solution at pH 7. Recognition is efficiently signaled through the displacement of the indicator 6-carboxyfluorescein bound to the receptor, monitoring its yellow fluorescent emission. Titration experiments evidenced the occurrence of several simultaneous equilibria involving 1:1 and 2:1 receptor/NMP and receptor/indicator complexes. It was demonstrated that the added NMP displaces the indicator from the 2:1 receptor/indicator complex, forming the 1:1 receptor/analyte inclusion complex. Recognition selectivity is thus ascribed to the nature of nucleotide donor atoms involved in the coordination and their ability to encompass the CuII−CuII distance within the cryptate.

Armando Buttafava

Papers

Understanding the molecular pathways associated with seed vigor

Sunlight-promoted photocatalytic hydrogen gas evolution from water-suspended cellulose: a systematic study

Recognition and sensing of nucleoside monophosphates by a dicopper(II) cryptate.

Gamma irradiation effects on stability of poly(lactide-co-glycolide) microspheres containing clonazepam.

The mechanism of chitosan degradation by gamma and e-beam irradiation