An integrated study for mapping the moisture distribution in an ancient damaged wall painting

An integrated study of microclimate monitoring, IR thermography (IRT), gravimetric tests and portable unilateral nuclear magnetic resonance (NMR) was applied in the framework of planning emergency intervention on a very deteriorated wall painting in San Rocco church, Cornaredo (Milan, Italy). The IRT investigation supported by gravimetric tests showed that the worst damage, due to water infiltration, was localized on the wall painting of the northern wall. Unilateral NMR, a new non-destructive technique which measures the hydrogen signal of the moisture and that was applied directly to the wall, allowed a detailed map of the distribution of the moisture in the plaster underlying the wall panting to be obtained. With a proper calibration of the integral of the recorded signal with suitable specimens, each area of the map corresponded to an accurate amount of moisture. IRT, gravimetric tests and unilateral NMR applied to investigate the northern wall painting showed the presence of two wet areas separated by a dry area. The moisture found in the lower area was ascribed to the occurrence of rising damp at the bottom of the wall due to the slope of the garden soil towards the northern exterior. The moisture found in the upper area was ascribed to condensation phenomena associated with the presence of a considerable amount of soluble, hygroscopic salts. In the framework of this integrated study, IRT investigation and gravimetric methods validated portable unilateral NMR as a new analytical tool for measuring in situ and without any sampling of the distribution and amount of moisture in wall paintings.     

Sequential single-shot imaging of nanoscale dynamic interactions with a table-top soft x-ray laser

We demonstrate the first real-space recording of nanoscale dynamic interactions using single-shot soft x-ray (SXR) full-field laser microscopy. A sequence of real-space flash images acquired with a table-top SXR laser was used to capture the motion of a rapidly oscillating magnetic nanoprobe. Changes of 30 nm in the oscillation amplitude were detected when the nanoprobe was made to interact with stray fields from a magnetic sample. The table-top visualization of nanoscale dynamics in real space can significantly contribute to the understanding of nanoscale processes and can accelerate the development of new nanodevices.     

Identification and structural characterization by LC-ESI-IONTRAP and LC-ESI-TOF of some metabolic conjugation products of homovanillic acid in urine of neuroblastoma patients

The levels of urinary catecholamine metabolites, such as homovanillic acid (HVA) and vanillylmandelic acid, are routinely used as a clinical tool in the diagnosis and follow-up of neuroblastoma (NB) patients. Recently, in the Clinical Pathology Laboratory Unit of G. Gaslini Children Hospital, a commercial method that employs liquid chromatography coupled to electrochemical detection (LC-EC) has been introduced for the measurement of these metabolites in the routine laboratory practice. Using this LC-EC method, an unknown peak could be observed only in samples derived from NB patients. To investigate the nature of this peak, we used a combination of liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) and liquid chromatography-ion trap tandem mass spectrometry (LC-IT-MS). The first approach was used to obtain the elemental composition of the ions present in this new signal. To get additional structural information useful for the elucidation of unknown compounds, the ion trap analyzer was exploited. We were able to identify not just one, but three unknown signals in urine samples from NB patients which corresponded to three conjugated products of HVA: HVA sulfate and two glucuronoconjugate isomers. The enzymatic hydrolysis with β-glucuronidase confirmed the proposed structures, while the selective alkaline hydrolysis allowed us to distinguish the difference between phenol- and acyl-glucuronide of HVA. The latter was the unknown peak observed in LC-EC separations of urine samples from NB patients.     

Shape-matching and classification using structural descriptors

Technological improvements related to object acquisition, visualisation and modelling, have caused a considerable growth of the number of 3D models in digital form. Digital 3D models are now available in large databases of shapes, ranging from unstructured repositories, like the web, to specialised catalogues used in engineering and simulation. In this panorama it is clear that methods for the retrieval and automatic classification of 3D content will play a crucial role in the development of efficient applications for the organisation and filtering of 3D data. In this paper, a methodology based on the coupling of geometric and structural information will be discussed for the global and partial matching of 3D shapes and for their automatic classification. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Underground spherical gravitational wave detector

Recently significant advancements have been made towards the realization of a large spherical gravitational wave detector. Research and development activities have already begun in several countries. We present here the main features and capabilities of a spherical gravitational wave detector. In particular, we discuss the interaction between a spherical antenna and cosmic rays that may require a large detector to be placed underground.     

Spontaneous Birefringence in Layer‐by‐Layer Films of Chitosan and Azo Dye Sunset Yellow

Layer‐by‐layer (LBL) films consisting of layers of the azo dye Sunset Yellow alternated with chitosan display spontaneous birefringence, which is attributed to the film anisotropy imparted by the LBL method. This is unusual for azobenzene‐containing materials as they normally form films with randomly oriented molecules, presenting birefringence only due to photoinduced isomerization cycles. Spontaneous birefringence does not appear in cast films, but occurs for LBL films obtained under various experimental conditions.

Chemical structures of (a) Sunset Yellow and (b) chitosan.     

Circular dichroic constrained structure optimization of homoalanine peptides

This article describes a new method for peptide structure optimization within a Monte Carlo Simulated Annealing (MCSA) framework, namely the cominimization of potential energies under the constraint of a calculated Circular Dichroism (CD) spectrum. We compute potential energy as well as the CD spectrum of every structure generated within the course of the MCSA run, and cooptimize the mean deviation of this calculated spectrum to a corresponding experimental spectrum together with the potential energies of the respective structures using a modified Metropolis Criterion within the MCSA scheme. We compare the performance of this technique with two other MCSA optimization variants—first, a cominimization of potential energies and free energies of solvation; and second, the standard minimization of potential energy alone. We use homoalanines in lengths of 10 and 15, whose optimized structures are highly α‐helical, and correspondingly give α‐helix characteristic CD signals as the test peptides. This circular dichroic constrained optimization of potential energies is, compared to the other methods, highly efficient in locating α‐helical structures with lowest potential energies in both the 10 alanine and the 15 alanine peptide system, within short MCSA runs. The overall structural information embedded in the CD spectrum efficiently guides the optimization towards the native peptide structure. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 270–281, 2000