Hydrogen Plasma and Thermal Annealing Treatments on a-Si:H Thin Film for c-Si Surface Passivation☆

Abstract High efficiency solar cells can be fruitfully built using the amorphous/crystalline silicon technology, taking advantage of the high V oc that occurs as a consequence of excellent c-Si surface passivation provided by a-Si:H films. Improvements of the interface quality can be obtained using post deposition treatments such as hydrogen plasma and thermal annealing. We propose the use of surface photovoltage technique, as a contact-less tool to evaluate the energetic distribution of the state density at amorphous/crystalline silicon interface, and FTIR spectroscopy of the same samples to appreciate the evolution of Si-H and Si-H 2 bonds. This approach leads to interesting applications for monitoring and improving the interface electronic quality, which is extremely susceptible to the different treatments adopted. We found that thermal annealing produces a metastable state which goes back to the initial state after just 48 hours, while the effect of hydrogen plasma post-treatment results more stable. Moreover H 2 plasma reduces the defect density of one order of magnitude with respect to thermal annealing and keeps it constant also after one month. The hydrogen plasma is able to reduce the defect density but at the same time increases the surface charge within the a-Si:H film due to the H + ions accumulated during the plasma exposure, leading to a more stable configuration

Correlative Microscopy Of Bone In Implant Osteointegration Studies.

Routine morphological analyses usually include investigations by light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Each of these techniques provides specific information on tissue morphology and all the obtained results are then combined to give an in-depth morphological overview of the examined sample. The limitations of this traditional comparative microscopy lie in the fact that each technique requires a different experimental sample, so that many specimens are necessary and the combined results come from different samples. The present study describes a technical procedure of correlative microscopy, which allows us to examine the same bone section first by LM and then, after appropriate processing, by SEM or TEM. Thanks to the possibility of analyzing the same undecalcified bone sections both by LM and SEM, the approach described in the present study allows us to make very accurate evaluations of old/new bone morphology at the bone-implant interface

Negative effects of a high tumour necrosis factor-α concentration on human gingival mesenchymal stem cell trophism: The use of natural compounds as modulatory agents

Background: Adult mesenchymal stem cells (MSCs) play a crucial role in the maintenance of tissue homeostasis and in regenerative processes. Among the different MSC types, the gingiva-derived mesenchymal stem cells (GMSCs) have arisen as a promising tool to promote the repair of damaged tissues secreting trophic mediators that affect different types of cells involved in regenerative processes. Tumour necrosis factor (TNF)-α is one of the key mediators of inflammation that could affect tissue regenerative processes and modify the MSC properties in in-vitro applications. To date, no data have been reported on the effects of TNF-α on GMSC trophic activities and how its modulation with anti-inflammatory agents from natural sources could modulate the GMSC properties. Methods: GMSCs were isolated and characterized from healthy subjects. The effects of TNF-α were evaluated on GMSCs and on the well-being of endothelial cells. The secretion of cytokines was measured and related to the modification of GMSC-endothelial cell communication using a conditioned-medium method. The ability to modify the inflammatory response was evaluated in the presence of Ribes nigrum bud extract (RBE). Results: TNF-α differently affected GMSC proliferation and the expression of inflammatory-related proteins (interleukin (IL)-6, IL-10, transforming growth factor (TGF)-β, and cyclooxygenase (COX)-2) dependent on its concentration. A high TNF-α concentration decreased the GMSC viability and impaired the positive cross-talk between GMSCs and endothelial cells, probably by enhancing the amount of pro-inflammatory cytokines in the GMSC secretome. RBE restored the beneficial effects of GMSCs on endothelial viability and motility under inflammatory conditions. Conclusions: A high TNF-α concentration decreased the well-being of GMSCs, modifying their trophic activities and decreasing endothelial cell healing. These data highlight the importance of controlling TNF-α concentrations to maintain the trophic activity of GMSCs. Furthermore, the use of natural anti-inflammatory agents restored the regenerative properties of GMSCs on endothelial cells, opening the way to the use and development of natural extracts in wound healing, periodontal regeneration, and tissue-engineering applications that use MSCs

14 MeV neutrons for 99Mo/99mTc production: Experiments, simulations and perspectives

Background: the gamma-emitting radionuclide Technetium-99m (99mTc) is still the workhorse of Single Photon Emission Computed Tomography (SPECT) as it is used worldwide for the diagnosis of a variety of phatological conditions.99mTc is obtained from99Mo/99mTc generators as pertechnetate ion, which is the ubiquitous starting material for the preparation of99mTc radiopharmaceuticals.99Mo in such generators is currently produced in nuclear fission reactors as a by-product of235U fission. Here we investigated an alternative route for the production of99Mo by irradiating a natural metallic molybdenum powder using a 14-MeV accelerator-driven neutron source. Methods: after irradiation, an efficient isolation and purification of the final99mTc-pertechnetate was carried out by means of solvent extraction. Monte Carlo simulations allowed reliable predictions of99Mo production rates for a newly designed 14-MeV neutron source (New Sorgentina Fusion Source). Results: in traceable metrological conditions, a level of radionuclidic purity consistent with accepted pharmaceutical quality standards, was achieved. Conclusions: we showed that this source, featuring a nominal neutron emission rate of about 1015s−1, may potentially supply an appreciable fraction of the current99Mo global demand. This study highlights that a robust and viable solution, alternative to nuclear fission reactors, can be accomplished to secure the long-term supply of99Mo

Stable incidence but declining case-fatality rates of subarachnoid hemorrhage in a population

Objective: To characterize temporal trends in subarachnoid hemorrhage (SAH) incidence and outcomes over 5 time periods in a large population-based stroke study in the United States. Methods: All SAHs among residents of the Greater Cincinnati/Northern Kentucky region at least 20 years of age were identified and verified via study physician review in 5 distinct year-long study periods between 1988 and 2010. We abstracted demographics, care patterns, and outcomes, and we compared incidence and case-fatality rates across the study periods. Results: The incidence of SAH in the 5 study periods (age-, race-, and sex-adjusted to the 2000 US population) was 8.8 (95% confidence interval 6.8–10.7), 9.2 (7.2–11.2), 10.0 (8.0–12.0), 9.0 (7.1–10.9), and 7.7 (6.0–9.4) per 100,000, respectively; the trend in incidence rates from 1988 to 2010 was not statistically significant (p = 0.22). Advanced neurovascular imaging, endovascular coiling, and neurologic intensive care unit availability increased significantly over time. All-cause 5-day (32%–18%, p = 0.01; for trend), 30-day (46%–25%, p = 0.001), and 90-day (49%–29%, p = 0.001) case-fatality rates declined from 1988 to 2010. When we included only proven or highly likely aneurysmal SAH, the declines in case-fatality were no longer statistically significant. Conclusions: Although the incidence of SAH remained stable in this population-based region, 5-day, 30-day, and 90-day case-fatality rates declined significantly. Advances in surgical and medical management, along with systems-based changes such as the emergence of neurocritical care units, are potential explanations for the reduced case-fatality

Geophysical monitoring of Stromboli volcano: insight into recent volcanic activity

Stromboli is an open conduit strato-volcano of the Aeolian archipelago (Italy), characterized by typical Strom-bolian explosive activity, lasting for several centuries, and by the emission of huge amounts of gas. The normalactivity of Stromboli is characterized by some hundreds of moderate explosions per day. Major explosions, whichlaunch scoria up to hundreds of meters from the craters, lava flows and paroxysmal explosions, which producelarge ballistic blocks, sometimes take place. During the effusive eruption in 2002 - 2003, which caused a tsunamiwith waves of about 10 meters high along the coasts of the Island, the monitoring system was enhanced. In 2006INGV has added two Sacks-Evertson borehole volumetric dilatometers to the surveillance system, in order to mon-itor changes in the local strain field by measuring areal strain. Today we have a large amount of geophysical dataand observations that allow us to better understand how this volcano works. After a period of low explosive activitystarted in mid-2014, Stromboli has shown a more intense explosive activity in the last few months. During the re-cent phase of increased activity, the geophysical monitoring system detected four major explosions occurred on 26July, 23 October, 1 November and 1 December 2017, respectively. The current phase of reawakening of Strombolivolcano has led the Italian civil protection authorities to decree the "attention" alert level (yellow) on the Island.PublishedVienna, Austria1IT. Reti di monitoraggio e sorveglianz

Measurements on hydrophobic and hydrophilic surfaces using a porous gamma alumina nanoparticle aggregate mounted on Atomic Force Microscopy cantilevers

Atomic Force Microscopy (AFM) measurements are extensively used for a detailed understanding ofmolecular and surface forces. In this study, we present a technique for measuring such forces, using an AFM cantilever attached with a porous gamma alumina nanoparticle aggregate. The modified cantilever was used to measure the forces of interaction of the aggregate with hydrophilic and hydrophobic surfaces. A strong force of attraction was observed between the aggregate and hydrophilic surfaces when the aggregate was kept dry. However, the force of interaction on the aggregate in wet form (water filled in pores) was larger when the adjoining surface had hydrophobic characteristics. The results presented in this study show the versatility of the current technique and indicate its usefulness in directly characterizing hydrophilic/ hydrophobic properties of nano-scale surfaces and patterns

Exploring mobility in Italian Neolithic and Copper Age communities

As a means for investigating human mobility during late the Neolithic to the Copper Age in central and southern Italy, this study presents a novel dataset of enamel oxygen and carbon isotope values (δ18Oca and δ13Cca) from the carbonate fraction of biogenic apatite for one hundred and twenty-six individual teeth coming from two Neolithic and eight Copper Age communities. The measured δ18Oca values suggest a significant role of local sources in the water inputs to the body water, whereas δ13Cca values indicate food resources, principally based on C3 plants. Both δ13Cca and δ18Oca ranges vary substantially when samples are broken down into local populations. Statistically defined thresholds, accounting for intra-site variability, allow the identification of only a few outliers in the eight Copper Age communities, suggesting that sedentary lifestyle rather than extensive mobility characterized the investigated populations. This seems to be also typical of the two studied Neolithic communities. Overall, this research shows that the investigated periods in peninsular Italy differed in mobility pattern from the following Bronze Age communities from more northern areas

Sex-related differences in risk factors, type of treatment received and outcomes in patients with atrial fibrillation and acute stroke: Results from the RAF-study (Early Recurrence and Cerebral Bleeding in Patients with Acute Ischemic Stroke and Atrial Fibrillation)

Introduction: Atrial fibrillation is an independent risk factor of thromboembolism. Women with atrial fibrillation are at a higher overall risk for stroke compared to men with atrial fibrillation. The aim of this study was to evaluate for sex differences in patients with acute stroke and atrial fibrillation, regarding risk factors, treatments received and outcomes. Methods Data were analyzed from the “Recurrence and Cerebral Bleeding in Patients with Acute Ischemic Stroke and Atrial Fibrillation” (RAF-study), a prospective, multicenter, international study including only patients with acute stroke and atrial fibrillation. Patients were followed up for 90 days. Disability was measured by the modified Rankin Scale (0–2 favorable outcome, 3–6 unfavorable outcome). Results: Of the 1029 patients enrolled, 561 were women (54.5%) (p < 0.001) and younger (p < 0.001) compared to men. In patients with known atrial fibrillation, women were less likely to receive oral anticoagulants before index stroke (p = 0.026) and were less likely to receive anticoagulants after stroke (71.3% versus 78.4%, p = 0.01). There was no observed sex difference regarding the time of starting anticoagulant therapy between the two groups (6.4 ± 11.7 days for men versus 6.5 ± 12.4 days for women, p = 0.902). Men presented with more severe strokes at onset (mean NIHSS 9.2 ± 6.9 versus 8.1 ± 7.5, p < 0.001). Within 90 days, 46 (8.2%) recurrent ischemic events (stroke/TIA/systemic embolism) and 19 (3.4%) symptomatic cerebral bleedings were found in women compared to 30 (6.4%) and 18 (3.8%) in men (p = 0.28 and p = 0.74). At 90 days, 57.7% of women were disabled or deceased, compared to 41.1% of the men (p < 0.001). Multivariate analysis did not confirm this significance. Conclusions: Women with atrial fibrillation were less likely to receive oral anticoagulants prior to and after stroke compared to men with atrial fibrillation, and when stroke occurred, regardless of the fact that in our study women were younger and with less severe stroke, outcomes did not differ between the sexes