Graphene enhanced field emission from InP nanocrystals.

We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the FE by Fowler-Nordheim theory and find that the field enhancement factor increases monotonically with the spacing between the anode and the cathode. We also show that InP/p-Si junction has a rectifying behavior, while graphene on InP creates an ohmic contact. Understanding the fundamentals of such nanojunctions is key for applications in nanoelectronics.

Organophosphate and phthalate esters in settled dust from apartment buildings in Stockholm.

In this study, the occurrence of nine phthalate diesters (phthalates) and 14 organophosphorus flame retardants (PFRs) was investigated in 62 house dust samples collected from 19 buildings in Stockholm area during the year 2008. Eight phthalates were detected in almost all samples, with median concentrations ranging from 0.47 µg/g to 449 µg/g with di(2-ethylhexyl) phthalate being the most abundant compound. Twelve PFRs were detected with median concentrations ranging from 0.19 µg/g to 11 µg/g. Within this class of compounds, the most abundant were tris(2-chloroisopropyl) and tris(2-butoxyethyl) phosphate. Both classes of compounds were also measured in the air of the apartments, but no correlation between air and dust concentrations could be found. Based on these measurements, exposure, via house dust ingestion and air inhalation, was calculated for adults and toddlers, and compared to published limit values in order to estimate potential health risks. In an extreme exposure scenario for toddlers, di(2-ethylhexyl) phthalate, tris(2-chloroethyl) phosphate, tris(2-butoxyethyl) phosphate, and tributyl phosphate were close to the reference dose for chronic oral exposure or the tolerable daily intake. Standard Reference Material SRM 2585 was used as a quality control sample, and the levels of diisononyl and diisodecyl phthalates were determined in this material.

Non-Invasive Identification of Atrial Fibrillation Driver Location Using the 12-lead ECG: Pulmonary Vein Rotors vs. other Locations.

Atrial fibrillation (AF) is an irregular heart rhythm due to disorganized atrial electrical activity, often sustained by rotational drivers called rotors. In the present work, we sought to characterize and discriminate whether simulated single stable rotors are located in the pulmonary veins (PVs) or not, only by using non-invasive signals (i.e., the 12-lead ECG). Several features have been extracted from the signals, such as Hjort descriptors, recurrence quantification analysis (RQA), and principal component analysis. All the extracted features have shown significant discriminatory power, with particular emphasis to the RQA parameters. A decision tree classifier achieved 98.48% accuracy, 83.33% sensitivity, and 100% specificity on simulated data.Clinical Relevance-This study might guide ablation procedures, suggesting doctors to proceed directly in some patients with a pulmonary veins isolation, and avoiding the prior use of an invasive atrial mapping system.

Osseointegrated implant for single-tooth replacement: a retrospective multicenter study on routine use in private practice.

BACKGROUND: Implant restorations first started with total edentulism. Later, the scientific community gave its approval for restorations in partial edentulism, and only recently some studies confirmed the validity of the treatment for single-tooth replacement. PURPOSE: The purpose of the study was to evaluate implant survival and prosthesis stability of Brånemark implants (titanium screws) when used routinely for single-tooth replacement in all regions. MATERIALS AND METHODS: Two hundred and fourteen patients received 252 implants for single-tooth replacement over a period of 8 years at five private clinics in Italy. The patients were treated in accordance with the protocol for Brånemark implants, and the data gathered have been analyzed according to established evaluation methods. RESULTS: During the observation period, 10 failures were recorded and 229 restorations were carried out. After the first year of loading, the total cumulative survival rate (CSR) was 96%, which then remained stable over the study time. The most frequent complication was loosening of the abutment screws (n = 22), amounting to 35% of all of the complications. This problem was related mainly to earlier types of abutments, whereas the more recent design, CeraOne abutment, showed a low frequency of screw loosening. CONCLUSIONS: The high survival rate, which is similar to that presented for prospective multicenter studies for single-tooth restorations with Brånemark implants, led to the conclusion that the use of this treatment modality is a reliable treatment for routine use in all oral regions.

Maxillary sinus augmentation using computer-aided design/computer-aided manufacturing (CAD/CAM) technology.

BACKGROUND: Maxillary sinus augmentation is a common method for increasing bone height for insertion of dental implants. In most cases, the graft is manually cut into a roughly appropriate shape by visual estimation during the operation; accordingly, the shape of the graft depends considerably on the experience of the surgeon. We have developed a computer-aided design/computer-aided manufacturing (CAD/CAM) technique to generate custom-made block grafts for sinus augmentation, and a customized cutting guide to precisely position the lateral wall and facilitate membrane elevation, using cone-beam computed tomography (CBCT). METHODS: Custom-made blocks of hydroxyapatite (HA) were preoperatively cut to the required shape, based on a three-dimensional (3D) simulation, using CAD/CAM technology. The custom-made HA blocks were used for sinus augmentation. RESULTS: Five patients underwent bilateral sinus elevation with custom-made HA blocks. Six months later, implants were placed. Two years after placement, all implants were in function. No clinical or prosthetic complications were encountered. CONCLUSIONS: We present a CAD/CAM technique for the fabrication of custom-made block grafts for sinus augmentation.

Sensitive thermal transitions of nanoscale polymer samples using the bimetallic effect: application to ultra-thin polythiophene.

A sensitive nanocalorimetric technology based on microcantilever sensors is presented. The technology, which combines very short response times with very small sample consumption, uses the bimetallic effect to detect thermal transitions. Specifically, abrupt variations in the Young's modulus and the thermal expansion coefficient produced by temperature changes have been employed to detect thermodynamic transitions. The technology has been used to determine the glass transition of poly(3-thiophene methyl acetate), a soluble semiconducting polymer with different nanotechnological applications. The glass transition temperature determined using microcantilevers coated with ultra-thin films of mass = 10(-13) g is 5.2 °C higher than that obtained using a conventional differential scanning calorimeter for bulk powder samples of mass = 5 × 10(-3) g. Atomistic molecular dynamics simulations on models that represent the bulk powder and the ultra-thin films have been carried out to provide understanding and rationalization of this feature. Simulations indicate that the film-air interface plays a crucial role in films with very small thickness, affecting both the organization of the molecular chains and the response of the molecules against the temperature.

Low HBeAg serum levels correlate with the presence of the double A1762T/G1764A core promoter mutation and a positive response to interferon in patients with chronic hepatitis B virus infection.

OBJECTIVE: To investigate the correlation of serum hepatitis B e antigen (HBeAg) levels with the presence of core promoter (CP) mutations, hepatitis B virus (HBV) viremia and the response to interferon (IFN) in patients with chronic hepatitis B. METHODS: Fourteen HBeAg-positive patients received alpha-2a IFN. Diluted serum samples of responders were tested for HBeAg positivity at dilutions of 1:40, 1:160 and 1:640 at the following time points: T0 (before starting IFN), T1 [at peak alanine aminotransferase (ALT) preceding HBeAg seroconversion], T2 (at ALT normalisation) and T3 (end of treatment). Nonresponder samples were similarly tested at times T0 and T3. The HBV CP and precore regions were sequenced at the same time points as for HBeAg testing. RESULTS: Six of 14 patients (43%) responded to IFN treatment and had lower HBeAg levels than nonresponders at T0 (p = 0.003). Five of 6 responders (83%) and none of the nonresponders had the A1762T/G1764A CP mutations (0/8, p < 0.003). At T0, HBeAg was negative at the 1:640 dilution in 5 of the 6 responders, who also had lower HBV DNA levels than nonresponders (p = 0.003). During IFN treatment, HBeAg levels decreased and HBV DNA became negative at T1 in responders. CONCLUSIONS: Low serum HBeAg and HBV DNA levels correlate with the presence of CP mutations and response to IFN treatment and can be considered as predictive markers of response to IFN.