Synthesis of thermoelectric magnesium-silicide pastes for 3D printing, electrospinning and low-pressure spray.

In this work, eco-friendly magnesium-silicide (Mg2Si) semiconducting (n-type) thermoelectric pastes for building components concerning energy-harvesting devices through 3D printing, spray and electrospinning were synthetized and tested for the first time. The Mg2Si fine powders were obtained through the combination of ball milling and thermal annealing under Ar atmosphere. While the latter process was crucial for obtaining the desired Mg2Si phase, the ball milling was indispensable for homogenizing and reducing the grain size of the powders. The synthetized Mg2Si powders exhibited a large Seebeck coefficient of ~ 487 µV/K and were blended with a polymeric solution in different mass ratios to adjust the paste viscosity to the different requirements of 3D printing, electrospinning and low-pressure spray. The materials produced in every single stage of the paste synthesis were characterized by a variety of techniques that unequivocally prove their viability for producing thermoelectric parts and components. These can certainly trigger further research and development in green thermoelectric generators (TEGs) capable of adopting any form or shape with enhanced thermoelectric properties. These green TEGs are meant to compete with common toxic materials such as Bi2Te3, PbTe and CoSb that have Seebeck coefficients in the range of ~ 290-700 µV/K, similar to that of the produced Mg2Si powders and lower than that of 3D printed bulk Mg2Si pieces, measured to be ~ 4866 µV/K. Also, their measured thermal conductivities proved to be significantly lower (~ 0.2 W/mK) than that reported for Mg2Si (≥ 4 W/mK). However, it is herein demonstrated that such thermoelectric properties are not stable over time. Pressureless sintering proved to be indispensable, but difficultly achievable by long thermal annealing (even above 32 h) in inert atmosphere at 400 °C, at least for bulk Mg2Si pieces constituted by a mean grain size of 2-3 µm. Hence, for overcoming this sintering challenge and become the silicide's extrusion viable in the production of bulk thermoelectric parts, alternative pressureless sintering methods will have to be further explored.

Stability under humidity, UV-light and bending of AZO films deposited by ALD on Kapton.

Aluminium doped zinc oxide (AZO) films were grown by Atomic Layer Deposition (ALD) on yellow Kapton and transparent Kapton (type CS) substrates for large area flexible transparent thermoelectric applications, which performance relies on the thermoelectric properties of the transparent AZO films. Therefore, their adhesion to Kapton, environmental and bending stability were accessed. Plasma treatment on Kapton substrates improved films adhesion, reduced cracks formation, and enhanced electrical resistance stability over time, of importance for long term thermoelectric applications in external environment. While exposure to UV light intensity caused the films electrical resistance to vary, and therefore their maximum power density outputs (0.3-0.4 mW/cm3) for a constant temperature difference (∼10 °C), humidity exposure and consecutive bending up to a curvature radius above the critical one (∼18 mm) not. Testing whether the films can benefit from encapsulation revealed that this can provide extra bending stability and prevent contacts deterioration in the long term.

Novel mutations in the SH3BP2 gene associated with sporadic central giant cell lesions and cherubism.

Central giant cell lesion (CGCL) is a reactive bone lesion that occurs mainly in the mandible, characterized by the multinucleated osteoclast-like giant cells in a background of oval to spindle-shaped mononuclear cells. The etiology is unknown and occurs more commonly in young adults. Cherubism, a rare disease found predominantly in females has histologic characteristics indistinguishable from those of CGCL and is caused by mutations mostly present in exon 9 of the SH3BP2 gene. In this study, we investigated four cases of CGCL and one case of cherubism. DNA was extracted from peripheral blood and tumor tissue and all coding and flanking regions of the SH3BP2 amplified by PCR and directly sequenced to identify underlying mutations. Two novel mutations were found; a heterozygous missense mutation c.1442A>T (Q481L) in exon 11 in one sporadic case of CGCL and a heterozygous germline and tumor tissue missense mutation c.320C>T (T107M) in exon 4 in one patient with cherubism. These findings open a new window to investigate the possible relationship between the pathogenesis of the cherubism and CGCL.

Human papillomavirus infection in Rio de Janeiro, Brazil: a retrospective study

There is considerable data to support a central role for human papillomavirus (HPV) in the etiology of cervical cancer. More than a 100 HPV types have been described, and 40 have been isolated from benign and malignant genital lesions. Consequently, there is strong motivation to evaluate HPV testing for cervical cancer screening. Few studies concerning the natural history of HPV infection have been conducted in the state of Rio de Janeiro. We determined the prevalence of HPV types in female genital lesions by using Hybrid Capture Assay (HCA) and we retrospectively analyzed the course of HPV infection. Our sample included 788 women attended at Laboratórios Sérgio Franco. The average age of the participants was 29.6 years. HPV prevalence and cytological diagnosis were determined. The overall prevalence of HPV DNA in the study group was 50.1 percent (395/788), ranging from 25 percent (NORMAL) to 100 percent in high-grade intraepithelial lesions (HSIL). High risk HPV was found in 12 percent inflammatory, 58.3 percent HPV, 63.2 percent LSIL and 100 percent HSIL. A retrospective analysis of 78 patients showed that 22 presented persistent lesions, 2 had progressive lesions, 4 had regressive lesions, 13 showed latent infections, 18 were transiently infected and 19 were submitted to curative treatment. No cases of cancer were registered in this population, which can afford private medical care and regular follow-up exams. We suggest that HCA be used in specific cases involving persistent and recurrent lesions.

Human papillomavirus infection in Rio de Janeiro, Brazil: a retrospective study.

There is considerable data to support a central role for human papillomavirus (HPV) in the etiology of cervical cancer. More than a 100 HPV types have been described, and 40 have been isolated from benign and malignant genital lesions. Consequently, there is strong motivation to evaluate HPV testing for cervical cancer screening. Few studies concerning the natural history of HPV infection have been conducted in the state of Rio de Janeiro. We determined the prevalence of HPV types in female genital lesions by using Hybrid Capture Assay (HCA) and we retrospectively analyzed the course of HPV infection. Our sample included 788 women attended at Laboratórios Sérgio Franco. The average age of the participants was 29.6 years. HPV prevalence and cytological diagnosis were determined. The overall prevalence of HPV DNA in the study group was 50.1% (395/788), ranging from 25% (NORMAL) to 100% in high-grade intraepithelial lesions (HSIL). High risk HPV was found in 12% inflammatory, 58.3% HPV, 63.2% LSIL and 100% HSIL. A retrospective analysis of 78 patients showed that 22 presented persistent lesions, 2 had progressive lesions, 4 had regressive lesions, 13 showed latent infections, 18 were transiently infected and 19 were submitted to curative treatment. No cases of cancer were registered in this population, which can afford private medical care and regular follow-up exams. We suggest that HCA be used in specific cases involving persistent and recurrent lesions.

Ameloblastin gene (AMBN) mutations associated with epithelial odontogenic tumors.

Ameloblastin (AMBN, MIM *601259) gene expresses an important protein (AMBN), present in the organic matrix of enamel. The AMBN protein has an important role in the differentiation of ameloblast cells and epithelium-mesenchyme signaling during odontogenesis which prompted us to investigate this gene in aggressive epithelial odontogenic tumors, such as ameloblastomas, and in some non-aggressive ones, such as the adenomatoid odontogenic tumor and the squamous odontogenic tumor. Six cases of epithelial odontogenic tumors were studied and normal cells of the patient's mucosa were used as negative controls. The results demonstrated novel mutations in all tumors, while mucosal cells showed the wild type DNA sequence. Our data demonstrates that AMBN gene has an important role in the tumorigenesis of subtypes of epithelial odontogenic tumors and that this phenotypic heterogeneity could be caused by genetic heterogeneity.

Investigation of the GSalpha gene in the diagnosis of fibrous dysplasia.

Fibrous dysplasia is a benign fibro-osseous disease of bone and its etiology has been previously established. Activating mutations in the gene that encodes the alpha subunit of stimulatory G protein (G(S)alpha) has been described in monostotic and polyostotic fibrous dysplasia and in the McCune-Albright syndrome. The present report describes a patient with monostotic fibrous dysplasia which diagnosis was confirmed by sequencing of the G(S)alpha gene, demonstrating a heterozygous missense mutation on codon 201 (201C --> T). Due to the high prevalence of G(S)alpha gene mutations in fibrous dysplasia in contrast to other benign and malignant fibrous-osseous lesions, mutational analysis are an additional and helpful parameter for the diagnosis of fibrous dysplasia in selected cases.

Idiopathic bone cavity: a clinical, radiographic, and histological study.

The aim of the present study was to evaluate the clinical, radiographic and histological characteristics of idiopathic bone cavities from the Oral Pathology archives at Universidade Federal de Minas Gerais. Forty-three cases were retrieved. Age, sex, some radiographic variables and morphological variables measured of the connective tissue, were studied. The results showed the men who developed cavities tended to be younger than women (median 16 years (range 11-48) compared with 18 (12-64)). Radiographically rounded lesions that were single, unilocular, and small were more common in younger patients. While rounded cavities occurred mainly in the anterior region, cavities with interdental scalloping occurred in the posterior area. The median age of the patients with thin connective tissue on the wall of the bony cavity was lower than that of those with a thicker lining. In conclusion, the present study shows that there is a significant relation between age and sex, radiographic and histological variables. These findings may contribute to the diagnosis of idiopathic bone cavities.

Oral myiasis by screwworm Cochliomyia hominivorax.

We report a rare case of periodontal myiasis by New World screwworm Cochliomyia hominivorax, an obligatory larval parasite, in a 66-year-old woman. The myiasis occurred in the anterior upper jaw associated with a pre-existent generalised periodontitis. About 40 larvae were removed from the lesion. One week later the periodontal tissues were healing normally and the patient was referred to a periodontist. As all of the larvae were in the last stage, they were probably deposited 5-7 days before.

Characteristics of drug resistance and HIV among tuberculosis patients in Mozambique.

SETTING: The rate of human immunodeficiency virus (HIV) seroprevalence among tuberculosis patients varies between 2% and 53% in Mozambique, depending on the region. Drug resistance surveillance has been performed in only a few cities in Mozambique. OBJECTIVES: To establish the extent of drug resistance in areas of Mozambique with different levels of HIV prevalence, to estimate the prevalence of HIV among tuberculosis (TB) patients, and to examine the association between drug resistance and HIV infection. DESIGN: All tuberculosis patients diagnosed at randomly selected health facilities over 9 months (September 1998 to June 1999) were enrolled in the study. Sputum was collected, smeared and cultured, and drug susceptibility tests were performed. Blood was tested for HIV in the respective provinces, and patients received pre-test and post-test counselling. RESULTS: Of 709 culture-positive cases, 25.5% were HIV-positive. HIV-positive patients were significantly more likely to have a prior history of treatment (OR 2.2; 95% CI 1.9-3.6) and resistance to both isoniazid and streptomycin (OR 2.3; 95% CI 1.3, 4.5). In patients with no history of prior tuberculosis treatment, the multidrug resistance rate was 3.4% and resistance to isoniazid and streptomycin (HS) was 5.2%. Any drug resistance was significantly more common among those with a history of prior treatment (OR 3.1; 95% CI 2.1-4.7), particularly resistance to HS (OR 4.5; 95% CI 2.6-7.9). CONCLUSIONS: This study demonstrates substantial levels of drug resistance in Mozambique. Differences in drug resistance between high and low HIV prevalence areas may be related to prior treatment.