Influence of dielectric breakdown on MOSFET drain current

Breakdown of gate dielectric is one of the most dangerous threats for reliability of MOSFET devices in operating conditions. Not only the gate leakage resulting from breakdown is a problem for power consumption issues, but the "on" drain current can be strongly affected. In this paper, we show that in recent technologies, featuring ultrathin gate dielectrics, the corruption of drain current due to breakdown can be modeled as the effect of a portion of channel being damaged by the opening of the breakdown spot. Devices featuring 2.2- and 3.5-nm-thick gate oxide and various channel widths are stressed by using a specialized setup, and the degradation of transistor parameters is statistically studied. The analysis shows that the radius of the damaged region responsible for drain current degradation can be estimated between 1.4 and 1.8 /spl mu/m.     

Malignant duodenocolic fistula: report of two cases, each with one or more other synchronous gastointestinal cancers

Two patients had duodenocolic fistulas, each following a carcinoma of the colon in the area of the hepatic flexure that had perforated into the duodenum. The first patient was treated by a radical pancreatoduodenectomy with right colectomy; the second by subtotal colectomy with excision of the duodenal wall and suture. Both patients are alive and without evidence of recurrent disease. In addition, the first patient had two other primary carcinomas, in the cecum and in the stomach, and the second patient had another primary in the sigmoid. The definitive procedure had to be adjusted to encompass all lesions. The radical operation in one stage seems to be the preferred procedure and certainly is most satisfactory as a cancer operation. Our patient treated by this procedure has survived more than 11 years. An intestinal fistula related to colonic carcinoma, evan though rare, should not be considered as a separate entity. Treatment of the cancer with an en-bloc resection of the communicating organs should be employed if possible.     

In‐Situ XRD Measurement and Quantitative Analysis of Hydrating Cement: Implications for Sulfate Incorporation in C–S–H

The study of hydration kinetics by in‐situ X‐ray powder diffraction can provide fundamental details on the time evolution of the phase assemblage in hydrating cement pastes. The main limit of the technique is the lack of quantitative information about the amount of C–S–H and unbound water, which cannot be measured directly by conventional quantitative phase analysis procedures based on X‐ray diffraction, due to their X‐ray amorphous nature. Here, a mass balance algorithm, which can be used to determine the amount of both C–S–H and capillary water, is presented and compared with methods based on standards. This method can also provide information about the stoichiometry of C–S–H formed by the reaction of C₃S, hydrated in the presence of gypsum, suggesting the incorporation of 0.3 mol of sulfate per mole of C–S–H precipitated. In addition, the results show a significant increase in the rate of C₃S hydration, when gypsum is added to the system.     

45S5 Bioglass®-derived scaffolds coated with organic–inorganic hybrids containing graphene

Highly porous 45S5 Bioglass®-based scaffolds fabricated by a foam replication technique were coated with electrically conductive organic–inorganic hybrid layers containing graphene by a solution method. α,ω-Triethoxysilane terminated poly (ethylene glycol) and tetraethoxysilane were used as the precursors of the organic–inorganic hybrid coatings, that contained 1.5 wt.% of homogeneously dispersed graphene nanoplatelets. The resulting coated scaffolds retained their original high porosity and interconnected pore structure after coating. The presence of graphene did not impair the bioactivity of the scaffolds in simulated body fluid.Initial tests carried out using MG-63 cells demonstrated that both uncoated scaffolds and scaffolds coated with organic/inorganic hybrids containing graphene offered the cultured cells an adequate surface for cell attachment, spreading and expression of extracellular matrix. The results showed that scaffolds coated with graphene are biocompatible and they can support cellular activity. The electrical conductivity introduced by the coating might have the potential to increase tissue growth when cell culture is carried out under an applied electric field.     

Traceability of Italian garlic (Allium sativum L.) by means of HRMAS-NMR spectroscopy and multivariate data analysis

(1)H High Resolution Magic Angle Spinning-Nuclear Magnetic Resonance (HRMAS-NMR) spectroscopy was used to analyse garlic (Allium sativum L.) belonging to red and white varieties and collected in different Italian regions, in order to address the traceability issue. 1D and 2D NMR spectra, performed directly on untreated small pieces of garlic, so without any sample manipulation, allowed the assignment of several compounds: organic acids, sugars, fatty acids, amino acids and the nutritionally important fructo-oligosaccharides and allyl-organosulphur compounds. Application of Partial Least Squares projections to latent structures-Discrimination Analysis provided an excellent model for the discrimination of both the variety and, most important, the place origin, allowing the identification of the metabolites contributing to such classifications. The presence of organosulphurs, allicin and some allyl-organosulphurs found by HRMAS-NMR, was confirmed also by SPME-GC-MS; 11 molecules were identified, containing from one up to three sulphur atoms and with and without allyl moieties.     

Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation

This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass‐ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne‐particle abrasion (AA). Cements were obtained from a Bis‐GMA/TEGDMA mixture filled with 60 mass% micron‐sized (1 ± 0.2 µm) or submicron‐sized (180 ± 30 µm) Ba‐Si‐Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student‐Newman‐Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA‐submicron group had lower bond strengths than the other groups. All AA‐submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb‐like aspect in the HFA‐treated ceramic, whereas the AA‐treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA‐treated compared to AA‐treated specimens. Cracks toward the bulk of the ceramic were observed in AA‐treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Microsc. Res. Tech. 77:363–367, 2014. © 2014 Wiley Periodicals, Inc.     

Oxidized graphene in ionic liquids for assembling chemically modified electrodes: a structural and electrochemical characterization study

Dispersions of graphene oxide (GO) nanoribbons in ionic liquids, ILs (either 1-butyl-3-methylimidazolium chloride (BMIM-Cl-) or 1-butylpyridinium chloride (-Bupy-Cl-)) have been used to assemble modified screen printed electrodes (SPEs). The graphene oxide/ionic liquid dispersions have been morphologically and structurally characterized by the use of several techniques: X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared (FT-IR) spectroscopy, high-resolution-transmission electron microscopy (HR-TEM). The assembled modified SPEs have then been challenged with various compounds and compared to several electro-active targets. In all cases high peak currents were detected, as well as significant potential shifts, especially in the detection of catecholamines and NADH, compared with the bare SPE and the conventional electrodes, such as glassy carbon (GC) and highly oriented pyrolitic graphite (HOPG). This opens the way to the assembly of new types of sensors and biosensors. The enhanced performances observed are attributed to electrocatalytic effects related to the high electrode surface area, to oxygen-assisted electron transfer, as well as to the disordering effect of the ILs, this latter related to the favorable π-π interactions with the ILs and the GO plane.     

Additive Manufacturing of Poly(Methyl Methacrylate) Biomedical Implants with Dual‐Scale Porosity

The development of bone permanent implants with a porous structure favoring their integration with the surrounding tissues is emerging as an attractive field of application of additive manufacturing (AM). This article reports on the investigation of the suitability of a hybrid AM technique, that is, computer‐aided wet‐spinning (CAWS), to fabricate novel poly(methyl methacrylate) (PMMA) constructs as porous implant prototypes. The optimization of the processing parameters to fabricate PMMA samples with a predefined internal porous structure and different external shapes is described. The study demonstrates that tailoring post‐processing conditions represents a powerful tool to optimize samples macroscopic aspect, micromorphology, and mechanical properties. In particular, the possibility of obtaining a dual‐scale porosity through the integration of the macroporous structure determined by the material lay‐down pattern with a submicrometric porosity resulting from the phase inversion process governing polymer solidification, together with the possibility of purifying the employed commercial material from residual monomer during coagulation in ethanol, are reported as noteworthy advantages of CAWS over other AM techniques. A natural progression of this work is the development of relevant complex anatomical prototypes with tailored porosity by processing digital data obtained from computer tomography imaging of bone defects.     

Low-field latent plasma damage depassivation in thin-oxide MOS

A novel plasma-process induced damage depassivation method is proposed. Using a staircase-like stress voltage and varying the stress time, we were able to depassivate the latent damage at very low-field on both nMOS and pMOS devices. The dynamic of the interface traps generation is studied; pMOS devices show a peculiar behavior, which can be explained understanding the mechanisms involved in damage depassivation. The energy of carriers is identified as the damaging factor.