On monomial curves and Cohen-Macaulay type

In this paper we characterize the monomial arithmetically Cohen-Macaulay curves in P^d and compute the type of their coordinate ring     

Experimental confirmation of a laser-induced temperature field model by means of microholographic interferometry

Summary The experimental validation of a mathematical model of the temperature field generated by the laser irradiation of a sample is shown. The test was performed on water, a material with well-known thermodynamic parameters. The experimental data were obtained by means of holographic interferometry. The validated model, in connection with the microholographic method, can be used to determine the thermodynamic properties of different materials.

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Riassunto Si presenta la validazione sperimentale di un modello matematico dei campi di temperatura generati dall’irraggiamento laser di campioni. Il test è stato eseguito sull’acqua, un materiale dai parametri termodinamici ben noti. I dati sperimentali sono stati ottenuti mediante interferometria microolografica. Il modello validato, congiuntamente al metodo microolografico, può essere usato per la caratterizzazione termica dei materiali.

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Резюме Экспериментально докаэывается справедливость математической модели температурного поля, образованного при лазерном облучении образца. Проверка проводилась на воде, т.е. материале с хорошо известными термодина-мическими параметрами. Экспериментальные данные получены с номощью голографической интерферометрии. Предложенная модель может быть использована для определениа термодинамических свойств различных материалов.

     

Nanostructured TiO x film on Si substrate: room temperature formation of TiSi x nanoclusters

We present a morphologic and spectroscopic study of cluster-assembled TiO _x films deposited by supersonic cluster beam source on clean silicon substrates. Data show the formation of nanometer—thick and uniform titanium silicides film at room temperature (RT). Formation of such thick TiSi _x film goes beyond the classical interfacial limit set by the Ti/Si diffusion barrier. The enhancement of Si diffusion through the TiO _x film is explained as a direct consequence of the porous film structure. Upon ultra high vacuum annealing beyond 600 °C, TiSi₂ is formed and the oxygen present in the film is completely desorbed. The morphology of the nanostructured silicides is very stable for thermal treatments in the RT—1000 °C range, with a slight cluster size increase, resulting in a film roughness an order of magnitude smaller than other TiO _x /Si and Ti/Si films in the same temperature range. The present results might have a broad impact in the development of new and simple TiSi synthesis methods that favour their integration into nanodevices.     

Development of a multiresidue method for analysis of major Fusarium mycotoxins in corn meal using liquid chromatography/tandem mass spectrometry

A sensitive and reliable liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method has been developed to determine, in a single run, eight trichothecenes, three fumonisins, zearalenone and alpha-zearalenol, in corn meal samples. LC and MS conditions were varied to find the best compromise in terms of sensitivity and separation. An acceptable compromise was obtained using a C18 column thermostatted at 45 degrees C and a mobile phase gradient of methanol/water with 10 mmol/L formate buffer (pH 3.8). A multiple reaction monitoring program, in which fumonisins and trichothecenes (except nivalenol and deoxynivalenol) are acquired in positive ESI as [M+H]+ or [M+NH4]+, and all other compounds in negative ESI, was developed to match appropriate retention time windows. Sample preparation used a simple homogenization of the corn meal sample with acetonitrile/water (75:25, v/v) followed by extraction on a C18 cartridge and clean-up on a cartridge containing graphitized carbon black. Method detection limits were in the range 2-14 ng/g, with the exception of nivalenol (27 ng/g), deoxynivalenol (40 ng/g) and 15-acetyldeoxynivalenol (30 ng/g). Good accuracy (recoveries 81-104%) and precision (RSD 4-11%) were obtained by performing calibration using a spiked analyte-free extract.     

Structural characteristics of different types of nanoparticles synthesised in mesomorphic metal alkanoates

The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC₈) and of the cobalt octanoate (CoC₈). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained.     

Comparison of three different enrichment strategies for serum low molecular weight protein identification using shotgun proteomics approach

Serum low-molecular weight (LMW) proteins potentially contain useful biological information and their identification can be used to discover novel potential biomarkers. Given the high complexity of serum samples, in the last years several different prefractionation and enrichment strategies have been developed. In this study three different methods, i.e. hydrogel nanoparticles, Proteominer^® peptide ligand affinity beads and Sartorius Vivaspin^® centrifugal ultrafiltration device, were compared and evaluated in order to select the best strategy for the enrichment and prefractionation of LMW proteins. A shotgun proteomics approach was adopted, with in-solution proteolytic digestion of the whole protein mixture and determination of the resulting peptides by nanoHPLC coupled with a high-resolution Orbitrap LTQ-XL mass spectrometer. Data analysis, focusing on the LMW proteome (MW ≤ 40 kDa), has shown that the hydrogel nanoparticles performed better in enriching the LMW protein profiles, with 115 proteins identified against 93 and 95 for Proteominer^® beads and Sartorius Vivaspin^® device, respectively.