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In this paper, we present integrated lead-free energy converters based on a suitable MEMS fabrication process with an embedded layer of LiNbO3. The fabrication technology has been developed to realize micromachined self-generating transducers to convert kinetic energy into electrical energy. The process proposed presents several interesting features with the possibility of realizing smaller scale devices, integrated systems, miniaturized mechanical and electromechanical sensors, and transducers with an active layer used as the main conversion element. When the system is fabricated in the typical cantilever configuration, it can produce a peak-to-peak open-circuit output voltage of 0.208 V, due to flexural deformation, and a power density of 1.9 nW·mm−3·g−2 at resonance, with values of acceleration and frequency of 2.4 g and 4096 Hz, respectively. The electromechanical transduction capability is exploited for sensing and power generation/energy harvesting applications. Theoretical considerations, simulations, numerical analyses, and experiments are presented to show the proposed LiNbO3-based MEMS fabrication process suitability. This paper presents substantial contributions to the state-of-the-art, proposing an integral solution regarding the design, modelling, simulation, realization, and characterization of a novel transducer.

INTRODUCTION Giant basal cell carcinoma (GBCC) is a tumor ≥5 cm in size, with aggressive biological behavior, that represents 1% of basal cell carcinomas (BCC), and studies regarding it are scarce. Our objective was to investigate the clinical-histopathological characteristics of GBCC and the risk factors associated with its development. METHODS A retrospective study over 8 years included patients with the clinical and histopathological diagnosis of GBCC. Age, sex, localization, size, evolution time, risk factors, and histological variants were compared to conventional BCC. Descriptive and inferential statistics were used, and a value of P

Background/objective Melanoma is the third most frequent malignant neoplasm in skin. The majority of information available comes from studies performed in Caucasian populations. Our objective was to investigate the clinico-pathological characteristics in Mexican patients with cutaneous melanoma and the relationship these characteristics had to prognosis. Methods A retrospective study included patients with a histopathological diagnosis of melanoma who were attended at a tertiary level Dermatology Institute over a 10-year period. Age, gender, anatomical location; histopathological subtype, Breslow thickness, Clark level; presence of ulceration, metastasis, anatomical-pathological stage and survival were investigated. To assess the data, descriptive statistics, chi-squared or the Fisher exact test and Kaplan-Meier curves were used. Results There were 323 patients included. The overall survival rate was 77% with an average follow-up of 7 years. The lowest survival was statistically related to the following: higher age (>65 years), localisation in palms/soles, histopathological nodular subtype, presence of ulceration, Breslow thickness >4.0 mm, Clark level V, the presence of metastasis and stage IV disease. Conclusions Our results relay the characteristics and prognosis of patients with the diagnosis of cutaneous melanoma in western Mexico.

Background: Psoriasis in children and adolescents has not been well studied in Mexico. Objective: To study the epidemiological characteristics of psoriasis in this age group. Methods: This is a retrospective study in an academic, tertiary care dermatology center from January 1999 to December 2014. We included patients ≤ 18 years of age, with clinical and histopathological diagnosis of psoriasis. We recorded the following information: gender, age, disease duration, clinical variant, nail involvement, treatment, and family history. Descriptive and inferential statistics were used for analysis. Results: Of 2,491 patients with psoriasis, 280 were ≤ 18 years of age, resulting in a prevalence of 11%. There was female predominance and the mean age was 11.5 years. Disease duration was 18 ± 34 months. Plaque psoriasis was the most common form, comprising 191 cases (68%). Nail involvement occurred in only 15 patients (5%). Topical treatment was given to 177 patients (63%). Only 14 cases (5%) had a family history of psoriasis. These variables did not differ when children were compared with adolescents, except in those with a shorter disease duration (13 ± 19 vs. 24 ± 29 months; p = 0.0004). Conclusions: We found a higher prevalence of psoriasis than previously published studies in this age group and a lower frequency of nail involvement and family history of psoriasis. (Rev Inves ClIn. 2017;69:47-50)

Background Porocarcinoma is a rare tumor, representing 0.005% of all malignant epithelial neoplasms. The majority of publications are single case reports. The objective of this study was to describe the epidemiologic and histopathologic characteristics of patients diagnosed with eccrine porocarcinoma. Methods A retrospective study was carried out from January 1994 to December 2010. Cases with a histopathological diagnosis of eccrine porocarcinoma were included. The investigated variables were frequency, gender, age, time of evolution, localization, morphology, referral clinical diagnosis, and histopathology patterns. The information was analyzed using descriptive statistics. Results During this 17-year period, 33 cases diagnosed with eccrine porocarcinoma were detected. Female gender was predominant with 64% cases. The average age was 74 ± 12 years. The most frequent location was the head with 37% cases; the most common observed morphology was nodular, in 46%. The main referral diagnosis was squamous cell carcinoma in 67% of cases. With regard to the histopathology characteristics, necrosis predominated in 64% cases, comedonecrosis in 45% cases, squamous differentiation in 42% cases, and melanocyte colonization in 21%. Conclusions Our series presents some clinical and histopathology differences with previously reported, such as the most frequent localization in the head and the presence of melanocyte colonization.

The objective of this paper is to apply the concepts and theories of global impact based on a modern formulation in which the impact is considered with sliding, adherence or transition between sliding and adherence. The energy dissipated in the contact may be quantified by different definitions of the coefficient of restitution in Newton’s law and Poisson’s law. The method is applied to the impact between the damper (parabolic elements) and the platform of the blades in an airborne gas turbine. A numerical solution is calculated using a computer program constructed on the Matlab Platform.

The study of dynamic and vibratory behavior of violins considers the effect of the different parts that compose it. The top and back plates have great importance in the transmission of vibrations and the characteristic tone of the violin; therefore, the study is centered in their vibratory behavior, since the ideal form of the vibrational modes and frequency of violins of greater prestige is known, according to bibliography. Modal Analysis Experimental tests determine the vibrational modes with their resonant frequencies of the violin plates. A numerical model of the top plate is made by means of the finite elements method, to determine the influence of the different mechanical and geometric properties on its main vibrational modes and natural frequencies; with the objective of obtaining the expected acoustic response, making precise changes in their structure. The height in the arching of the plates is modified to obtain different effects on the frequencies and the vibrational modes. A sensibility analysis is applied on a finite elements model of the top plate, to determine the influence of the thickness in different zones on its natural frequencies, and to study the effect produced by the thickness variations of the bass bar. With an optimisation study the thickness distribution is modified to obtain the ideal natural frequencies and achieve the right vibratory behaviour, with a similar dynamic response as violins of greater prestige.

In this paper, we present integrated lead-free energy converters based on a suitable MEMS fabrication process with an embedded layer of LiNbO3. The fabrication technology has been developed to realize micromachined self-generating transducers to convert kinetic energy into electrical energy. The process proposed presents several interesting features with the possibility of realizing smaller scale devices, integrated systems, miniaturized mechanical and electromechanical sensors, and transducers with an active layer used as the main conversion element. When the system is fabricated in the typical cantilever configuration, it can produce a peak-to-peak open-circuit output voltage of 0.208 V, due to flexural deformation, and a power density of 1.9 nW·mm−3·g−2 at resonance, with values of acceleration and frequency of 2.4 g and 4096 Hz, respectively. The electromechanical transduction capability is exploited for sensing and power generation/energy harvesting applications. Theoretical considerations, simulations, numerical analyses, and experiments are presented to show the proposed LiNbO3-based MEMS fabrication process suitability. This paper presents substantial contributions to the state-of-the-art, proposing an integral solution regarding the design, modelling, simulation, realization, and characterization of a novel transducer.