A new view of electrochemistry at highly oriented pyrolytic graphite

Major new insights on electrochemical processes at graphite electrodes are reported, following extensive investigations of two of the most studied redox couples, Fe(CN)64–/3– and Ru(NH3)63+/2+. Experiments have been carried out on five different grades of highly oriented pyrolytic graphite (HOPG) that vary in step-edge height and surface coverage. Significantly, the same electrochemical characteristic is observed on all surfaces, independent of surface quality: initial cyclic voltammetry (CV) is close to reversible on freshly cleaved surfaces (>400 measurements for Fe(CN)64–/3– and >100 for Ru(NH3)63+/2+), in marked contrast to previous studies that have found very slow electron transfer (ET) kinetics, with an interpretation that ET only occurs at step edges. Significantly, high spatial resolution electrochemical imaging with scanning electrochemical cell microscopy, on the highest quality mechanically cleaved HOPG, demonstrates definitively that the pristine basal surface supports fast ET, and that ET is not confined to step edges. However, the history of the HOPG surface strongly influences the electrochemical behavior. Thus, Fe(CN)64–/3– shows markedly diminished ET kinetics with either extended exposure of the HOPG surface to the ambient environment or repeated CV measurements. In situ atomic force microscopy (AFM) reveals that the deterioration in apparent ET kinetics is coupled with the deposition of material on the HOPG electrode, while conducting-AFM highlights that, after cleaving, the local surface conductivity of HOPG deteriorates significantly with time. These observations and new insights are not only important for graphite, but have significant implications for electrochemistry at related carbon materials such as graphene and carbon nanotubes

Valutazione dell\u2019impatto economico delle infezioni ospedaliere in Lombardia: risultati di uno studio in 88 ospedali

Objectives: To assess the consumption levels of proton pump inhibitors (PPIs) in Italy, in comparison with some foreign markets. To investigate the practice in PPI prescribing in Italy, in comparison with consumption standards. Design: The DDD (Defined Daily Dose) tool was adopted as the best unit of measure to be used in fulfilling the first objective. With regard to the second objective, in order to estimate the PDDs (Prescribed Daily Doses) in the PPI area, a large sample (8940 prescription episodes) was drawn from the Health Search database, a facility created by Societ\ue0 Italiana di Medicina Generale and supported by a number of pharmaceutical companies. Results: The Italian PPI market size was 198.2 million DDDs in 2000 (more than twice the 1995 data), corresponding to 9.4 DDDs per 1000 people per day (that is, about 1% of the Italian population is treated every day with PPIs). In the same year, PPI consumption was 16.5 DDDs per 1000 people per day in France and 19.3 in the UK. In Italy, the ratio between PPI and H2-antagonists consumption (1.6) was lowest, as compared with France (4.5) and with UK (1.8). With regard to omeprazole, the prescription practice (weighted average PDD: 25.4 mg) was higher than its standard (DDD: 20 mg); similar results were found for pantoprazole (46 vs 40 mg) and rabeprazole (22.2 vs 20 mg). On the contrary, lansoprazole's PDD (23.4 mg) was lower than its DDD (30 mg); however, the average length of therapy with lansoprazole turned out to be longer. Conclusions: The PPI market is expanding in Italy, although to a lesser extent and with more competition from H2-antagonists as compared with France and the UK. When evaluating prescription practices and their costs, the DDD tool has clear limitations, while PDD is a better measure. However, not only PDD amounts but also lengths of therapies should be taken into consideration in order to formulate sound judgements about treatment costs

Prevalence of nosocomial infections in Italy: result from the Lombardy survey in 2000

A one-day survey was carried out in 88 out of 113 public hospitals in Lombardy to obtain prevalence rates of hospital-acquired infections (HAIs) by hospital departments and to identify the pathogens more frequently involved. In total 18 667 patients were surveyed, representing 72% of the average daily total of occupied beds in public hospitals in Lombardy. The overall prevalence of HAI was 4.9%. The highest prevalence was observed in intensive care units and in spinal units. The prevalence of bloodstream infections was 0.6%; pneumonia 1.1%; urinary tract infections 1.6% and gastrointestinal infections 0.4%. In surgical patients the prevalence of surgical site infections was 2.7%. The most frequently isolated pathogen from all sites of infections was Escherichia coli (16.8%), followed by Staphylococcus aureus (15.0%), Pseudomonos aeruginosa (13.2%) and Candida spp. (8.7%). Methicillin-resistant S. aureus accounted for 23% of all isolated S. aureus. The results provide baseline data for rational priorities in allocation of resources, for further studies and for infection control activities. (C) 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved

Progress in OCT-based Through Silicon Via (TSV) metrology

International audienceWe report on progress in Time-Domain OCT (optical coherence tomography) applied to TSV (vertical interconnect accesses in silicon, enabling stacking of devices). Transitioning from the common scalar approach to an electromagnetic one, and combining it with a damped least squares approach, we enhance the accuracy of TSV height measurements

Incipient anion intercalation of highly oriented pyrolytic graphite close to the oxygen evolution potential: a combined x-ray photoemission and raman spectroscopy study

In the present work, we used two different electrochemical (EC) techniques, namely, cyclic voltammetry and normal pulsed voltammetry, applied to a highly oriented pyrolytic graphite (HOPG) electrode for anion intercalation in two different aqueous electrolytes (i.e., perchloric and sulphuric acid). We performed comparative X-ray photoemission (XPS) and Raman spectroscopy studies at various EC potentials. The chemical analysis obtained by XPS and Raman spectroscopy, the latter applied in situ and in real time during the EC processes, indicates that at oxygen evolution potential (i.e., before reaching the well-known intercalation stage potentials), the HOPG intercalation process is already active. These results suggest that the intercalated compound is efficiently obtained before reaching higher potentials, which usually cause a detriment of the graphite crystal