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Lanthanum oxide (La2O3) thin films have been prepared on Si(100) substrates through a sol−gel process from the lanthanum methoxyethoxide (La(OCH2CH2OCH3)3) precursor. To study the effects of different postdeposition treatments on film microstructure and optical properties, the as-deposited layers have been annealed at different temperatures between 200 and 700 °C in air or forming gas (H210% in N2) for 1 h. Low-temperature (300 °C) remote O2plasma processing has also been applied to both as-deposited and previously annealed samples. Films have been fully characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), glancing incidence X-ray diffraction (GIXRD), and atomic force microscopy (AFM). In particular, microstructure and optical properties correlations were accomplished by exploiting spectroscopic ellipsometric investigation. It has been found that thermal annealing at temperatures around 500 °C leads to subcutaneous oxidation of the Si substrate resulting in the formation of a SiO2layer, and annealing at higher temperature (700 °C) also results in film−substrate intermixing and formation of a lanthanum silicate layer. At variance, these interfacial reactions can be suppressed by low-temperature (300 °C) remote O2plasma processing of as-deposited films, and optical transparency in the visible range can be strongly improved.

The present contribution is devoted to outlining some recent results from an innovative approach to metal oxide nanosystems. The proposed synthesis pathway is based on three successive steps: i) preparation of a porous xerogel layer (host) via sol–gel (SG); ii) CVD of a guestphase on the above matrix, making it possible to achieve an intimate host/guestintermixing; iii) ex situ thermal treatment under suitable conditions, aimed at tailoring the system properties as a function of the desired application. In particular, the above route has been adopted in two specific cases, LaCoO3and CeO2–ZrO2nanostructured thin films, which are acquiring increasing importance in the development of fuel cell technology. The most significant results, obtained by glancing incidence X‐ray diffraction (GIXRD), atomic force microscopy (AFM), X‐ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and transmission electron microscopy (TEM), will be critically discussed, emphasizing the achievement of tailored material properties by design.

Nanocomposite silica glassy layers (host) containing copper-based species (guest) were developed and tailored by the sol−gel route. The systems were obtained by starting from ethanolic solutions of tetraethoxysilane (Si(OC2H5)4, TEOS) and copper(II) acetate (Cu(CH3COO)2·4H2O) in a single-step process and subsequently annealed ex situ under different atmospheres (air, nitrogen, or 4% H2 in N2 mixture). In particular, the attention was focused on the possibility of tailoring the system composition and microstructure through a proper choice of the treatment temperatures (100−900 °C), duration (1−5 h), and environment. The composite evolution under annealing was investigated by glancing incidence X-ray diffraction, optical absorption spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Pure copper−silica-based nanosystems, with guest composition ranging from CuO to Cu and controllable particle size and distribution, were obtained. The stepwise formation of CuO, Cu2O, and Cu nanoclusters in the silica network as a function of the adopted conditions is critically discussed, highlighting the crucial points involved in the design and development of composites endowed with peculiar chemicophysical properties.

A novel combined PE‐CVD/sol–gel approach to oxide‐based nanosystems is proposed and employed for the synthesis of CeO2–ZrO2nanocomposites. The method consists of the plasma‐enhanced (PE) CVD of ceria (guest) on a zirconia xerogel ZrOx(OH)y(OR)z(host) prepared by sol–gel (SG) at a temperature of 200 °C. The system evolution under annealing in air (600 °C and 900 °C, 1 h) and its mutual relationships with the synthesis conditions were investigated in detail by a multi‐technique characterization. The proposed synthetic pathway enables the synthesis of CeO2–ZrO2nanostructured systems ranging from composites to solid solutions, as a function of thermal treatment and Ce/Zr ratio as well. In this framework, particular attention is devoted to achieving an intimate Ce/Zr intermixing by exploiting the synergy between the SG xerogel properties (porosity, –OH content) and the peculiar actions exerted by plasma (ablation/deposition, infiltration power). Such features enable an in‐depth penetration of ceria into the inner zirconia xerogel layers already in the as‐grown systems.

An original synthetic approach to Au/TiO2 nanosystems is developed. The adopted technique is based on the RF-sputtering of gold (guest) on porous titania xerogels (host) obtained by the sol−gel route. Such a combined synthetic pathway joins the peculiarities offered by the features of the sol−gel layers (porosity, nonbridging groups) and the advantages of plasmochemical methods (conformal coverage, infiltration power). In particular, host titania substrates were first prepared on silica by dip-coating from ethanolic solutions of Ti(OPrⁱ)4 (OPrⁱ=iso-propoxy) and Hacac (2,4-pentanedione). Subsequently, Au depositions were performed on the as-prepared xerogels in Ar plasmas at low temperatures. The resulting samples were finally annealed in air between 200 and 600 °C with the aim of tailoring the system features as a function of thermal treatment and gold content. Their structural, compositional, and morphological evolution was investigated by Glancing Incidence X-ray Diffraction (GIXRD), Transmission Electron Microscopy (TEM), optical absorption spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM). The adopted strategy enabled the synthesis of Au/TiO2 nanosystems with characteristics strongly dependent on the deposited gold amount and processing conditions. In this way, materials with tunable structure, composition, and optical properties could be synthesized.

Monolithic borophosphosilicate glasses were prepared by the sol−gel route through xerogel densification. Tetramethoxysilane (Si(OCH3)4), trimethylborate (B(OCH3)3), and trimethyl phosphite (P(OCH3)3) were used as source compounds for Si, B, and P, respectively. After drying, samples underwent thermal treatment up to 700 °C with alternating flowing oxygen and reduced pressure steps, resulting in transparent, monolithic glasses. The sample chemical composition was analyzed by X-ray photoelectron spectroscopy (XPS). Densification was investigated by vibrational spectroscopies (FT-IR, micro-Raman). The boron oxygen hole centers (BOHC) and phosphorus oxygen hole centers (POHC) paramagnetic defects generated by X-ray irradiation of glasses were studied by electron paramagnetic resonance (EPR) spectroscopy. The results obtained on borophosphosilicate glasses showed that paramagnetic defects are not created by independent processes, as expected for randomly distributed noninteracting B and P doping elements. Diamagnetic precursors of BOHC and POHC are thus proposed to be spatially close together in the glasses.

Nanophasic LaCoO3powders were synthesized from inorganic compounds both in molten chloride fluxes and by using a solution combustion synthesis procedure. The samples were prepared in air and underwent subsequent heat treatments in order to yield the perovskite crystalline phase. The composition and microstructure of the samples were investigated by XPS, x‐ray‐induced AES, x‐ray diffraction and electron paramagnetic resonance. Further information was gained by magnetic measurements. Nanophasic LaCoO3powders with an average crystallite size of 35 nm were obtained. Copyright © 2002 John Wiley & Sons, Ltd.

The association between Down's syndrome (DS) and celiac disease (CD) has been confirmed by several authors. The sensitivity and specificity of antigliadin antibodies (AGAs), the clinical features of subjects with DS and CD (DS-CD +), the incidence of CD, and the results of serological and molecular class I and II HLA typing were determined in a sample of 57 Sicilian subjects with DS. Six (10.5%) and 17 subjects (29.8%) showed high level of IgA AGAs and IgG AGAs, respectively. AGAs sensitivity and specificity were lower than in the population without DS. Ten people with DS were submitted to jejunal biopsy, and seven (12.2%) showed CD according to ESPGAN criteria. All seven patients were put on gluten-free diet, followed by rapid disappearance of symptoms. Class I and II HLA serological and molecular typing was carried out in seven DS-CD + subjects, 22 people with DS without CD (DS-CD -), five subjects with CD without DS, and 20 controls. Between DS-CD + and DS-CD - subjects, no statistically significant difference regarding serum HLA class I antigens was found. DQA1 *0101 allele appears significantly in DS-CD + patients and deserves to be searched for in a larger sample to assess its meaning in the DS-CD association.

The recombinant Cu,Zn superoxide dismutase from the South African frog Xenopus laevis, expressed in E. coli, has been crystallized in a form suitable for high resolution crystallographic investigations. The crystals grow from polyethylene glycol solutions, at pH 6.0, 28° C, and belong to the orthorhombic space group P2₁2₁2₁ with unit cell edges a = 73.33, b = 68.86, c = 59.73 Å, one protein dimer (32,000 Mr) per asymmetric unit. Diffraction data have been collected to 3.0 Å resolution, and a molecular replacement solution found for Xenopus laevis superoxide dismutase using the bovine enzyme as search model. The crystallographic R-factor corresponding to this solution is 0.412, in the 15.0-3.0 Å resolution range.Copyright 1993, 1999 Academic Press

Bone metabolism may be disturbed in children with celiac disease. Two markers of bone turnover were used: the level of osteocalcin (BGP) and the level of carboxylterminal peptide of type I procollagen (PICP). BGP and PICP were measured by radioimmunoassays in 18 untreated children with celiac disease (mean age: 22.9 ± 15.6 months) and in 15 control subjects (mean age 28.5 ± 21 months). All the patients were rechecked after 1 month and again after 3 months from beginning of a gluten‐free diet (GFD). Compared with controls at diagnosis our patients had significantly lower serum levels of BGP and PICP (p = 0.003 and p = 0.018 by Student's ttest, respectively). These levels increased markedly during the 1st 3 months of GFD. The alteration in calcium phosphate homeostasis caused by celiac disease directly affects the synthesis of both components of the connective matrix of bone. Measurements of BGP and PICP provide a reliable and rapidly obtainable index of normalization of the processes of bone growth which can be achieved with a GFD.

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Selective IgA deficiency was observed in 12 of 688 (1.7%) patients with celiac disease who were clinically undistinguishable from patients with celiac disease with normal IgA levels. This high prevalence of IgA deficiency in patients with celiac disease makes serum IgA assay advisable when screening for celiac disease is performed by measurement of antigliadin antibodies or anti-IgA endomysium antibodies. Similarly, subjects with IgA deficiency should be considered at risk of celiac disease. (J Pediatr 1997;131:306-8)