Spatial and temporal distribution of environmental markers from Coastal to Plateau areas in Antarctica by firn core chemical analysis

The chemical analysis of shallow firn cores sampled in coastal and plateau areas in Northern Victoria Land and along a transect from Talos Dome to Dome C (East Antarctica, Pacific Ocean sector) allowed a global view of spatial and temporal changes in chemical composition of snow depositions over the last 100 years. Variations in concentration of primary (sea spray) and secondary (biogenic emission, atmospheric inputs) source markers were observed and discussed as a function of distance from the sea and altitude.

In the stations characterized by relatively high snow accumulation rates, the sub-sampling resolution was sufficient to obtain a stratigraphic dating by using the periodical variations of seasonal markers. In these stations, a subdivision in “summer” and “winter” samples was carried out in order to study the seasonal changes of the contributions of the measured compounds to the snow composition as elevation and distance from the sea increase.

Some evidence of post-depositional effects which are able to change the original deposition of chloride and nitrate, was observed at stations with low accumulation rates. The reliability of the depth/concentration profile of these substances for reconstructing past deposition was also discussed.     

A Semisynthetic Approach to New Immunoadjuvant Candidates: Site‐Selective Chemical Manipulation of Escherichia coli Monophosphoryl Lipid A

A semisynthetic approach to novel lipid A derivatives from Escherichia coli (E. coli) lipid A is reported. This methodology stands as an alternative to common approaches based exclusively on either total synthesis or extraction from bacterial sources. It relies upon the purification of the lipid A fraction from fed‐batch fermentation of E. coli, followed by its structural modification through tailored, site‐selective chemical reactions. In particular, modification of the lipid pattern and functionalization of the phosphate group as well as of the sole primary hydroxyl group were accomplished, highlighting the unusual reactivity of the molecule. Preliminary investigations of the immunostimulating activity of the new semisynthetic lipid A derivatives show that some of them stand out as promising, new immunoadjuvant candidates.     

Palladium‐Catalyzed Heteroaromatic Couplings Mediated by Microwave Irradiation

Nitrogen‐containing heterocycles bearing a halogen substituent have been converted to the corresponding amines by a synthetic protocol based on Buchwald methodology assisted by microwaves.     

Photochemical- and pH-switching Properties of a New Photoelastic Ligand Based Upon Azobenzene. Basicity and Anion Binding

Abstract

The synthesis of a new cylindrical macrotricyclic ligand (L) based upon two 1,4,7,13-tetramethyl-1,4,7,10,13,16-hexaazacyclooctadecane rings connected via two azobenzene pillars is described. The ligands displays photoelastic properties: light absorption at 366 nm produces trans→cis isomerization of the azobenzene moieties with formation of trans-cis (L _E-Z ) and cis-cis (L _Z-Z ) isomers. Recovery of the thermodynamically more stable trans-trans (L _E-E ) isomer can be obtained by thermal back-isomerization or visible light (430 nm) absorption. The isomeric composition of L solution depends upon pH: for pH < 5.5 the L _E-E form is the unique species in solution, while increasing amounts of Z species are formed at increasing pH. The protonation constants of L _E-E have been determined in 0.1 mol dm^?3 Me₄NNO₃ solution at 298.1 ± 0.1 K. The protonated species of L form stable inclusion complexes with anionic species such as [Co(CN)₆]^3?.     

Design and synthesis of fluorescent galactolipid probes

Fluorescent galactolipid analogues (1, 1a, and 2) have been synthesized with a pyrene group attached to the amino-terminal of a hexanoyl chain bound to an otherwise normal galactolipid structure. The synthetic lipids are obtained from peracetyl galactose by a general and versatile procedure based on the trichloroacetimidate methodology. The intense violet fluorescence (376 and 395 nm) and good photostability of pyrene make these compounds highly suitable as probes to study galactolipid metabolism. As proof of concept, we report that compound 2 is a valid tool to detect galactolipase activity in enzymatic preparations of potato tubers.     

Comparing comparisons between vehicular traffic states in microscopic and macroscopic first‐order models

In this paper, we deal with the analysis of the solutions of traffic flow models at multiple scales in both cases of a single road and road networks. We are especially interested in measuring the distance between traffic states (as they result from the mathematical modeling) and investigating whether these distances are somehow preserved passing from the microscopic to the macroscopic scale. By means of both theoretical and numerical investigations, we show that, on a single road, the notion of Wasserstein distance fully catches the human perception of distance independently of the scale, while in the case of networks it partially loses its nice properties.     

Tracking dissipation in capture reactions

Nuclear dissipation in capture reactions is investigated using backtracing, a new analysis protocol. Combining analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing between quasifission and fusion-fission is solved for the first time. The nature of the relevant dissipation is determined as one-body dissipation. At low excitation energy where shell effects are strongly effective, the shape of the mass distribution could be a powerful check of the nature and the magnitude of the dissipation.     

Identification of RFLP G6PD mutations by using microcapillary electrophoretic chips (Experion)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most well-known human genetic defects, identified in more than 400 million individuals in the world. To date, no commercial kits are available for the mutation screening of this disease. Seventy G6PD-deficient Italian individuals admitted to the Laboratory of Clinical Molecular Biology of Hospital "Agostino Gemelli" of Rome were screened for the most frequent Italian mutations, by means of allele-specific PCR, followed by restriction fragment length electrophoresis. The present study compares two techniques for the identification of restriction patterns: agarose gel electrophoresis versus Experion system. When the first screening was negative, the entire G6PD gene was sequenced using the ABI 3100 Avant Instrumentation. The G6PD variants identified and their frequencies were the following: G6PD Mediterranean (75.7%), G6PD Seattle (7.1%), G6PD A(-) 202 + 376 (7.1%), and G6PD Cassano (2.8%). In addition, we identified by direct sequencing two new mutations, namely Buenos Aires and Rignano. With the Experion method, the size band determination was more accurate than that obtained by gel electrophoresis. The Experion system resulted as a valid, easy, and reproducible diagnostic method for the screening of G6PD mutation as compared with the agarose electrophoretic analysis.     

Two molecular assays for the rapid and inexpensive detection of GJB2 and GJB6 mutations

The hypoacusia can be classified in two clinical forms: Syndromic (SHL) and Nonsyndromic (NSHL). In particular, the NSHL describes the 70–80% of hypoacusia cases and it is mainly due to genetic factors, which are causative of the deafness at the birth. The genetic hypoacusia presents different inheritance patterns: autosomal dominant (20%), autosomal recessive (80%), X‐linked (1%), and mitochondrial (1%), respectively. To date, about 35 deafness‐causative genes have been identified and most of them codify for connexin transmembrane proteins. Approximately 1:2500 children with NSHL carries mutations in the GJB2 and GJB6 (13q12) genes, which code for connexin 26 (Cx26) and connexin 30 (Cx30), respectively. In the Caucasian population, the most common mutations are 35delG, M34T and 167delT, and D13S1830. Given the frequency distribution of the four mutations in the Caucasian population and the pathogenic connection with NSHL, the development of accurate, rapid, and “low‐cost” molecular assays should be strongly encouraged. To this purpose, we set up two different molecular assays (namely the Cx26 and Cx26‐30 molecular assays) for the fast and inexpensive detection of 35delG, M34T, 167delT, and D13S1830 mutations. Both the molecular approaches showed to be accurate, sensitive, reproducible, and “low‐cost” alternatives for the proper evaluation of the GJB2 and GJB6 genes, which are causative of NSHL. In conclusion, the Cx26 and Cx26‐30 molecular assays can be applied to individual, preconception, prenatal, or postnatal screening for the causative‐mutations of NSHL.     

Oil-in-water nanocontainers as low environmental impact cleaning tools for works of art: two case studies

A novel class of p-xylene-in-water microemulsions mainly based on nonionic surfactants and their application as low impact cleaning tool in cultural heritage conservation is presented. Alkyl polyglycosides (APG) and Triton X-100 surfactants allow obtaining very effective low impact oil-in-water (o/w) microemulsions as alternatives to pure organic solvents for the removal of polymers (particularly Paraloid B72 and Primal AC33) applied during previous conservation treatments. The ternary APG/p-xylene/water microemulsions have been characterized by quasi elastic light scattering to obtain the hydrodynamic radius and the polydispersity of the microemulsion droplets. Laplace inversion of the correlation function CONTIN analysis provided evidence of acrylic copolymers solubilization into the oil nanodroplets. Contact angle, Fourier transform infrared (FTIR), and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) data confirmed that microemulsions were effective in removing polymer coatings. The phase diagram of APG microemulsions showed that a reduction >90% (compared to the conventional cleaning methods) of the organic solvent can be achieved by using o/w microemulsions. The microemulsions were successfully tested in two real cases: (1) the APG based microemulsion was used in a Renaissance painting by Vecchietta in Santa Maria della Scala, Siena, Italy, degraded by the presence of a polyacrylate coating applied during a previous restoration and (2) a Triton X-100 oil-in-water microemulsion containing (NH4)2CO3 in the water continuous phase. The association of ammoniun carbonate to the microemusion led to the swelling of an organic deposit (mainly asphaltenes deposited on the fresco in the Oratorio di San Nicola al Ceppo in Florence, still contamined by the water of the Arno river during the 1966 flood) and a very efficient removal of highly insoluble inorganic deposits (mainly gypsum) strongly associated to asphaltenes. These innovative systems are very attractive for the low amount of organic solvent used to extract the polymers or highly insoluble substances as the asphaltene and the very efficient and mild impact of the cleaning procedure on the fragile painted surfaces.