Variable expressivity of osteogenesis imperfecta in a Brazilian family due to p.G1079S mutation in the COL1A1 gene

Osteogenesis imperfecta (OI) is a Mendelian disease with genetic heterogeneity characterized by bone fragility, recurrent fractures, blue sclerae, and short stature, caused mostly by mutations in COL1A1 or COL1A2 genes, which encode the pro-alpha 1(I) and pro-alpha 2(I) chains of type I collagen, respectively. A Brazilian family that showed variable expression of autosomal dominant OI was identified and characterized. Scanning for mutations was carried out using SSCP and DNA sequence analysis. The missense mutation c.3235G>A was identified within exon 45 of the COL1A1 gene in a 16-year-old girl diagnosed as having OI type I; it resulted in substitution of a glycine residue (G) by a serine (S) at codon 1079 (p.G1079S). The proband's mother had the disease signs, but without bone fractures, as did five of nine uncles and aunts of the patient. All of them carried the mutation, which was excluded in four healthy brothers of the patient's mother. This is the first description in a Brazilian family with OI showing variable expression; only one among seven carriers for the c.3235G>A mutation developed bone fractures, the most striking clinical feature of this disease. This finding has a significant implication for prenatal diagnosis in OI disease.

Effect of dental tissue conditioners and matrix metalloproteinase inhibitors on type I collagen microstructure analyzed by Fourier transform infrared spectroscopy

This study aimed to evaluate the chemical interaction of collagen with some substances usually applied in dental treatments to increase the durability of adhesive restorations to dentin. Initially, the similarity between human dentin collagen and type I collagen obtained from commercial bovine membranes of Achilles deep tendon was compared by the Attenuated Total Reflectance technique of Fourier Transform Infrared (ATR-FTIR) spectroscopy. Finally, the effects of application of 35% phosphoric acid, 0.1M ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine, and 6.5% proanthocyanidin solution on microstructure of collagen and in the integrity of its triple helix were also evaluated by ATR-FTIR. It was observed that the commercial type I collagen can be used as an efficient substitute for demineralized human dentin in studies that use spectroscopy analysis. The 35% phosphoric acid significantly altered the organic content of amides, proline and hydroxyproline of type I collagen. The surface treatment with 0.1M EDTA, 2% chlorhexidine, or 6.5% proanthocyanidin did not promote deleterious structural changes to the collagen triple helix. The application of 6.5% proanthocyanidin on collagen promoted hydrogen bond formation. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.

Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests

The uplift capacity of helical anchors normally increases with the number of helical plates. The rate of capacity gain is variable, considering that the disturbance caused by the anchor installation is generally more pronounced in the soil mass above the upper plates than above the lower plates, because the upper soil layers are penetrated more times. The present investigation examines the effect of the number of helices on the performance of helical anchors in sand, based on the results of centrifuge model tests. Uplift loading tests were performed on 12 different types of piles installed in two containers of dry sand prepared with different densities. The measured fractions of the uplift capacity related to each individual helical plate of multi-helix anchors were compared with the fractions predicted by the individual bearing method. The results of this investigation indicate that in double- and triple-helix anchors, the contributions of the second and third plate to the total anchor uplift capacity decreased with the increase of sand relative density and plate diameter. In addition, these experiments demonstrated that the variation of the anchor load-displacement behavior with the number of helices also depends on these parameters.

Surface-Potential-Based Drain Current Analytical Model for Triple-Gate Junctionless Nanowire Transistors

This paper proposes a drain current model for triple-gate n-type junctionless nanowire transistors. The model is based on the solution of the Poisson equation. First, the 2-D Poisson equation is used to obtain the effective surface potential for long-channel devices, which is used to calculate the charge density along the channel and the drain current. The solution of the 3-D Laplace equation is added to the 2-D model in order to account for the short-channel effects. The proposed model is validated using 3-D TCAD simulations where the drain current and its derivatives, the potential, and the charge density have been compared, showing a good agreement for all parameters. Experimental data of short- channel devices down to 30 nm at different temperatures have been also used to validate the model.

Delays in the diagnosis of tuberculosis in a town at the triple border of Brazil, Paraguay, and Argentina

Objective. To identify the factors linked to patients and health services in delays in the diagnosis of tuberculosis. Methods. Epidemiological study in Foz do Iguacu, Parana, Brazil, 2009. The Primary Care Assessment Tool, adapted for appraising tuberculosis treatment, was the instrument used. Descriptive statistics techniques were used, such as frequency distributions, central tendency and dispersion measurements (median and interquartile intervals), and odds ratios. Results. There were greater delays in seeking health services for those in the age group 60 years and older, for females, for patients with low levels of education, and for patients with poor knowledge of the disease. Clinical variables (being a new case and HIV infection) and behavioral variables (use of tobacco and alcohol consumption) were not linked with delays in diagnosis. The median time delays before diagnosis attributable to patients and to the health services were 30 days and 10 days, respectively. Emergency 24-hour medical services and primary health care services were not effective in identifying suspicious cases of tuberculosis and requesting tests to confirm the diagnosis, with a high percentage of referrals to the Tuberculosis Control Program clinic. Conclusions. Going to primary health care services for diagnosis increased the time before diagnosis of the disease was reached. The Tuberculosis Control Program clinic was more effective in diagnosis of tuberculosis, due to the training of the staff and to an organized process for receiving patients, including the availability of tests to support the diagnosis.

Effect of Solvent-Induced Coil to Helix Conformational Change on the Two-Photon Absorption Spectrum of Poly(3,6-phenanthrene)

This paper investigates the effect of solvent-induced conformational changes of poly(3,6-phenanthrene) on their two-photon absorption (2PA). Such effect was studied employing the wavelength-tunable femtosecond Z-scan technique and modeled using the sum-over-essential states approach. We observed a strong reduction of the 2PA cross-section when the sample was prepared in hexane (poor solvent) in comparison to chloroform (good solvent), which is related to the conformation adopted by the polymer in each case. In chloroform it adopts a random coil conformation, as opposed to the one-handed helix conformation in hexane. Our results pointed out that the coil to helix conformation change decreases the degree of molecular planarity of the polymer pi-conjugated backbone, which is primarily responsible for their optical nonlinearity, contributing to diminishing the effective transition dipole moments and, consequently, the 2PA cross-section. Moreover, by studying the nonlinear response with different light polarization, we showed that, although the solvent-induced conformational change does not alter the molecular symmetry of the polymer, it modifies considerably the direction of the transition dipole moments between the excited states.

An analytic method to compute the stress dependence on the dimensions and its influence in the characteristics of triple gate devices

Triple-gate devices are considered a promising solution for sub-20 nm era. Strain engineering has also been recognized as an alternative due to the increase in the carriers mobility it propitiates. The simulation of strained devices has the major drawback of the stress non-uniformity, which cannot be easily considered in a device TCAD simulation without the coupled process simulation that is time consuming and cumbersome task. However, it is mandatory to have accurate device simulation, with good correlation with experimental results of strained devices, allowing for in-depth physical insight as well as prediction on the stress impact on the device electrical characteristics. This work proposes the use of an analytic function, based on the literature, to describe accurately the strain dependence on both channel length and fin width in order to simulate adequately strained triple-gate devices. The maximum transconductance and the threshold voltage are used as the key parameters to compare simulated and experimental data. The results show the agreement of the proposed analytic function with the experimental results. Also, an analysis on the threshold voltage variation is carried out, showing that the stress affects the dependence of the threshold voltage on the temperature. (C) 2011 Elsevier Ltd. All rights reserved.

Behavior of triple-gate Bulk FinFETs with and without DTMOS operation

In this paper, the combination of the Dynamic Threshold (DT) voltage technique with a non-planar structure is experimentally studied in triple-gate FinFETs. The drain current, transconductance, resistance, threshold voltage, subthreshold swing and Drain Induced Barrier Lowering (DIBL) will be analyzed in the DT mode and the standard biasing configuration. Moreover, for the first time, the important figures of merit for the analog performance such as transconductance-over-drain current, output conductance. Early voltage and intrinsic voltage gain will be studied experimentally and through three-dimensional (3-D) numerical simulations for different channel doping concentrations in triple-gate DTMOS FinFETs. The results indicate that the DTMOS FinFETs always yield superior characteristic; and larger transistor efficiency. In addition, DTMOS devices with a high channel doping concentration exhibit much better analog performance compared to the normal operation mode, which is desirable for high performance low-power/low-voltage applications. (C) 2011 Elsevier Ltd. All rights reserved.

Analysis of temperature variation influence on the analog performance of 45 degrees rotated triple-gate nMuGFETs

This work presents the analog performance of n-type triple-gate MuGFETs with high-k dielectrics and TiN gate material fabricated in 45 degrees rotated SOI substrates comparing their performance with standard MuGFETs fabricated without substrate rotation. Different fin widths are studied for temperatures ranging from 250 K up to 400 K. The results of transconductance, output conductance, transconductance over drain current ratio, intrinsic voltage gain and unit-gain frequency are studied. It is observed that the substrate rotation improves the carrier mobility of narrow MuGFETs at any temperature because of the changing in the conduction plane at the sidewalls from (1 1 0) to (1 0 0). For lower temperatures, the improvement of the carrier mobility of rotated MuGFETs is more noticeable as well as the rate of mobility improvement with the temperature decrease is larger. The output conductance is weakly affected by the substrate rotation. Although this improvement in the transconductance of rotated MuGFETs is negligibly transferred to the intrinsic voltage gain, the unity-gain frequency of rotated device is improved due to the larger carrier mobility in the entire range of temperatures studied. (C) 2011 Elsevier Ltd. All rights reserved.