Photophysics of Deoxycytidine and 5-Methyldeoxycytidine in Solution: A Comprehensive Picture by Quantum Mechanical Calculations and Femtosecond Fluorescence Spectroscopy.

The study concerns the relaxation of electronic excited states of the DNA nucleoside deoxycytidine (dCyd) and its methylated analogue 5-methyldeoxycytidine (5mdCyd), known to be involved in the formation of UV-induced lesions of the genetic code. Due to the existence of four closely lying and potentially coupled excited states, the deactivation pathways in these systems are particularly complex and have not been assessed so far. Here, we provide a complete mechanistic picture of the excited state relaxation of dCyd/5mdCyd in three solvents-water, acetonitrile, and tetrahydrofuran-by combining femtosecond fluorescence experiments, addressing the effect of solvent proticity on the relaxation dynamics of dCyd and 5mdCyd for the first time, and two complementary quantum mechanical approaches (CASPT2/MM and PCM/TD-CAM-B3LYP). The lowest energy ππ* state is responsible for the sub-picosecond lifetime observed for dCyd in all the solvents. In addition, computed excited state absorption and transient IR spectra allow one, for the first time, to assign the tens of picoseconds time constant, reported previously, to a dark state (nOπ*) involving the carbonyl lone pair. A second low-lying dark state, involving the nitrogen lone pair (nNπ*), does significantly participate in the excited state dynamics. The 267 nm excitation of dCyd leads to a non-negligible population of the second bright ππ* state, which affects the dynamics, acting mainly as a "doorway" state for the nOπ* state. The solvent plays a key role governing the interplay between the different excited states; unexpectedly, water favors population of the dark states. In the case of 5mdCyd, an energy barrier present on the main nonradiative decay route explains the 6-fold lengthening of the excited state lifetime compared to that of dCyd, observed for all the examined solvents. Moreover, C5-methylation destabilizes both nOπ* and nNπ* dark states, thus preventing them from being populated.

Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models.

The optical spectra of 5-methylcytidine in three different solvents (tetrahydrofuran, acetonitrile, and water) is measured, showing that both the absorption and the emission maximum in water are significantly blue-shifted (0.08 eV). The absorption spectra are simulated based on CAM-B3LYP/TD-DFT calculations but including solvent effects with three different approaches: (i) a hybrid implicit/explicit full quantum mechanical approach, (ii) a mixed QM/MM static approach, and (iii) a QM/MM method exploiting the structures issuing from molecular dynamics classical simulations. Ab-initio Molecular dynamics simulations based on CAM-B3LYP functionals have also been performed. The adopted approaches all reproduce the main features of the experimental spectra, giving insights on the chemical-physical effects responsible for the solvent shifts in the spectra of 5-methylcytidine and providing the basis for discussing advantages and limitations of the adopted solvation models.

An experimental and theoretical study of the photoisomerization and thermal reversion on 5-arylmethylene-2-thioxoimidazolidin-4-one.

Unraveling the photochemical behaviour of the green fluorescent protein chromophore has lately attracted widespread attention among scientists. In this paper we present the study of the photochemical isomerization Z → E and the back reaction of the chromophore analog, 5-arylmethylene-2- thioxoimidazolidin-4-one. Experimental results are supported with ab initio calculations at the DFT, (B3LYP/6-31+g(d,p)), TD-DFT (B3LYP/6-311++g(3df,3pd)) and CASSCF levels. A first excitation to the S2 state, where the isomerization occurs, is proposed followed by two conical intersections to S1 and S0 respectively. Three different mechanisms were analyzed for thermal reversion, concluding that the preferred channel involves an intersystem crossing between the S0 and T1 states with the formation of a biradical.

MInD: moving in the dark.

Visually-impaired people can develop several unhealthy behaviors, including the lack of physical activity or sports, due to the incomplete maturity in the control of their body in the space. This research focuses on the creation of an "exergame" - a videogame especially designed to stimulate physical exercise - that, through voice commands, allows the visually impaired users to practice physical activity and train their abilities. This tool has been developed starting from an existing dance-game, by generating some appropriate interfaces that also involve the sensory channel of sight. Our research aims to study the effects related to this exergame on the motor control mechanism in a blind children's group, aged between 8 and 13 years: it focuses also on the joint use of movement analysis systems and of videogames in order to stimulate the physical activity in these subjects.

The telematic network of referee hospital "V. Monaldi" in Naples: state of the art and perspectives.

The new advances in I.T. both in Hardware (wideband network) and in Software are rapidly changing the Health Information Systems scenario. In many hospitals of Campania Region this leads in many case to rebuild, starting from zero, both infrastructure and applications. Ericsson Enterprise has recently developed for the A.O. Monaldi and Integrated information System which consists of an advanced LAN (Local Area Network), a number of software infrastructures and some application systems as WEB site, Dicom PACS, E-mail server, Streaming Video from Operating Theatres, Internal TV Network. This integrated system represents the starting point for modern health information systems, which is compliant with new standards. The start-up of such systems represents always a problem for the organization and management point of view, therefore a number of problems concerning: training, education, security, privacy, operative procedures, co-ordination with existing applications, system management at the start-up and after. This paper deals with the technical aspects of this information system and discusses the problem met in introducing these IT products in a big and important hospital of Campania Region in Italy, in order to suggest a model, useful for other similar experiences.

Functional fields in human auditory cortex revealed by time-resolved fMRI without interference of EPI noise.

The gradient switching during fast echoplanar functional magnetic resonance imaging (EPI-fMRI) produces loud noises that may interact with the functional activation of the central auditory system induced by experimental acoustic stimuli. This interaction is unpredictable and is likely to confound the interpretation of functional maps of the auditory cortex. In the present study we used an experimental design which does not require the presentation of stimuli during EPI acquisitions and allows for mapping of the auditory cortex without the interference of scanner noise. The design relies on the physiological delays between the onset, or the end, of stimulation and the corresponding hemodynamic response. Owing to these delays and through a time-resolved acquisition protocol it is possible to analyze the decay of the stimulus-specific signal changes after the cessation of the stimulus itself and before the onset of the EPI-acoustic noise related activation (decay-sampling technique). This experimental design, which might permit a more detailed insight in the auditory cortex, has been applied to the study of the cortical responses to pulsed 1000 Hz sine tones. Distinct activation clusters were detected in the Heschl's gyri and the planum temporale, with an increased extension compared to a conventional block-design paradigm. Furthermore, the comparison of the hemodynamic response of the most anterior and the posterior clusters of activation highlighted differential response patterns to the sound stimulation and to the EPI-noise. These differences, attributable to reciprocal saturation effects unevenly distributed over the superior temporal cortex, provided evidence for functionally distinct auditory fields.

Exploring brain function with magnetic resonance imaging.

Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology.

Localisation and characterisation of auditory perception through Functional Magnetic Resonance Imaging.

In the last few years, Functional Magnetic Resonance Imaging (fMRI) has been widely accepted as an effective tool for mapping brain activities in both the neurosensorial and the cognitive field. The present work aims to assess the possibility of using fMRI methods to perform a non-invasive evaluation of the human auditory function. To this end the cortical response to different non speech stimuli (pure tones, pulsed tones) was examined for ten subjects with no audiological impairment. Our findings point out some remarkable differences in both the spatial and the temporal features of the primary auditory cortex response to pulsed tones and to pure tones.

AUDIOMAT: an electronic newspaper for visually impaired people.

Electronic newspapers are now becoming available via wide-area computer networks, such as the internet. Unfortunately, the Windows-based graphical user interface of the client programs makes it difficult for visually impaired people to use such services. Furthermore, few visually impaired people have a PC. The AUDIOMAT project was designed to provide a reading system for the visually impaired, thus giving this community in the Campania region of southern Italy the opportunity to read their local newspaper. In a pilot trial, three blind subjects used the AUDIOMAT system daily for two months. Despite some minor technical problems the system performed well and a wider validation phase is now planned.

A quantitative approach in the treatment of hemiplegic patients using an electropneumatic platform.

Exercise is the central feature in the rehabilitative treatment of hemiplegic patients. In cognitive rehabilitation, great importance is attributed to the recovery of a sufficient number of proprioceptive channels before expecting the patient to regain voluntary control. The PERM [Piattaforma (Platform), Elettropneumatica (Electropneumatic) per (for) Riabilitazione (Rehabilitation) Motoria (Motor)] is a new device that can be used in the treatment of the lower limbs to provide the patient with controlled and quantifiable mechanical stimuli, thus enabling the therapist to adopt a more rigorous approach to treatment even in the very early stages of rehabilitation. Alternatively, the system can be used in a different operating mode as a normal biofeedback system capable of displaying on-screen the extent to which voluntary load has been transferred to the lower limb.

Medical technologies in developing countries: a feasibility study on the maintenance of medical equipment in Ethiopia.

The authors report the results of a feasibility study, sponsored by the Italian Foreign Ministry, of setting up a Regional Centre for the Management and Maintenance of Medical Technologies in Ethiopia. After some general considerations regarding the problems of co-operation in this field, the authors draft some concrete proposals for an operative programme.

Medical technologies in developing countries: a pilot programme for the setting up of a regional centre for maintenance of medical equipment in Ethiopia.

In the last years a new approach to cooperation programmes with developing countries has been followed. It critically considers cooperation as donation and makes a big contribution to cooperation for the development of developing countries. For such reasons some topics such as 'education' and the 'management of the health services and technologies' have become more important than in the past. The authors report, first on some general aspects of the cooperation programmes in this field and, secondly, on some experiences relating to a cooperation programme for the management of medical technologies in Ethiopia.

An adjustment method for spinal cord stimulators based on simplified gait analysis (1).

The use of electrical stimulators, for pain relief, spasticity reduction, and other applications, is greatly increasing; the programming facilities of the new devices extend the application range and allow to reduce the manufacturing costs. On the other side it is necessary to define methodologies and protocols for a custom setting of these devices. This work, although for only one patient, is a proposal for a methodology, based on a simplified gait analysis, for the adjustment of a spinal cord electrical stimulator.