A comprehensive review on the corrosion pathways of titanium dental implants and their biological adverse effects

The main aim of this work was to perform a comprehensive review of findings reported by previous studies on the corrosion of titanium dental implants and consequent clinical detrimental effects to the patients. Most studies were performed by in vitro electrochemical tests and complemented with microscopic techniques to evaluate the corrosion behavior of the protective passive oxide film layer, namely TiO2. Results revealed that bacterial accumulation, dietary, inflammation, infection, and therapeutic solutions decrease the pH of the oral environment leading to the corrosion of titanium. Some therapeutic products used as mouthwash negatively affect the corrosion behavior of the titanium oxide film and promote changes on the implant surface. In addition, toothpaste and bleaching agents, can amplify the chemical reactivity of titanium since fluor ions interacting with the titanium oxide film. Furthermore, the number of in vivo studies is limited although corrosion signs have been found in retrieved implants. Histological evaluation revealed titanium macro- and micro-scale particles on the peri-implant tissues. As a consequence, progressive damage of the dental implants and the evolution of inflammatory reactions depend on the size, chemical composition, and concentration of submicron- and nanoparticles in the surrounding tissues and internalized by the cells. In fact, the damage of the implant surfaces results in the loss of material that compromises the implant surfaces, implant-abutment connections, and the interaction with soft tissues. The corrosion can be an initial trigger point for the development of biological or mechanical failures in dental implants.This study was supported by FCT-Portugal (UID/EEA/04436/2013, NORTE-01-0145-FEDER- 000018– HAMaBICo, POCI-01-0145-FEDER-031035_LaserMULTICER) and CNPq-Brazil (CNPq/UNIVERSAL/421229/2018-7

A Framework for Dimensioning VDL-2 Air-Ground Networks

This paper describes a framework developed at MITRE for dimensioning a Very High Frequency (VHF) Digital Link Mode 2 (VDL-2) Air-to-Ground network. This framework was developed to support the FAA's Data Communications (Data Comm) program by providing estimates of expected capacity required for the air-ground network services that will support Controller-Pilot-Data-Link Communications (CPDLC), as well as the spectrum needed to operate the system at required levels of performance. The Data Comm program is part of the FAA's NextGen initiative to implement advanced communication capabilities in the National Airspace System (NAS). The first component of the framework is the radio-frequency (RF) coverage design for the network ground stations. Then we proceed to describe the approach used to assess the aircraft geographical distribution and the data traffic demand expected in the network. The next step is the resource allocation utilizing optimization algorithms developed in MITRE's Spectrum ProspectorTM tool to propose frequency assignment solutions, and a NASA-developed VDL-2 tool to perform simulations and determine whether a proposed plan meets the desired performance requirements. The framework presented is capable of providing quantitative estimates of multiple variables related to the air-ground network, in order to satisfy established coverage, capacity and latency performance requirements. Outputs include: coverage provided at different altitudes; data capacity required in the network, aggregated or on a per ground station basis; spectrum (pool of frequencies) needed for the system to meet a target performance; optimized frequency plan for a given scenario; expected performance given spectrum available; and, estimates of throughput distributions for a given scenario. We conclude with a discussion aimed at providing insight into the tradeoffs and challenges identified with respect to radio resource management for VDL-2 air-ground networks

Parallel Generation of Association Rules – Use Case: Psychometric Evaluation

Mining of association rules consists of determining relations among variables in the form of rules in large databases, one of the algorithms most used to perform this task is the Apriori algorithm. This article proposes the parallelization of the Apriori algorithm applied to the Cattell’s questionnaire Sixteen Personality Factor, known as the 16PF questionnaire, to generate association rules among different questions. The use case used has a database that contains 49,150 questionnaires answered, with 163 questions per questionnaire. Results obtained show four times less execution time between the proposed parallel algorithm and the serial algorithm, in addition, the results show associations with confidence values greater than 97% (with two variables) and greater than 98% (with three variables), which it would be expected from the point of view of traditional psychology.     Keywords: rules of association, Apriori algorithm, parallelization, personality questionnair

Perception of medical students about courses based on peer-assisted learning in five Peruvian universities

Objectives: Peer-assisted learning (PAL) is a supportive strategy in medical education. In Peru, this method has been implemented by few universities. However, there are no consistent studies evaluating their acceptability by medical students. The objective of this study was to evaluate the perception of medical students about PAL in five Peruvian universities. Results: A total of 79 medical students were included in the study. The mean age was 20.1 ± 1.9 years, 54% were female, and 87% were in the first 4 years of study. Most of the students were satisfied with classes and peer teachers. Similarly, most of the students agreed with the interest in developing teaching skills. It was also observed that 97% of students approved to implement PAL in medical education programs.Revisión por pare

Características físicas y perfil de diámetro de fibra de alpacas Huacaya del Centro Experimental La Raya (Puno, Perú), según edad y sexo

The technological characteristics and the fibre diameter profile were determined according to age (1, 3, 5, 7 years) and sex (male, female) of Huacaya alpacas from the La Raya Experimental Centre (Puno, Peru). Fleece samples were taken from the middle rib at shearing and analysed with the OFDA 2000 equipment. The data were adjusted to multiple quadratic regression for the analysis of the exchange rates. The average diameter, comfort factor, curvature index and fibre length were statistically similar between sexes, while for age, the diameter increased (from 19.48 ± 0.25 to 24.82 ± 0.80 µm), and both the comfort factor (from 98.15 to 86.95%) and the fibre length (from 102.18 ± 12.92 to 75.00 ± 11.34 mm) decreased, while the curvature index shows no defined trend. The parameters that characterize the fibre diameter profile showed a single maximum value of the mean fibre diameter, which showed a concave curve with two ascending and descending segments. Exchange rates were positive and negative, although their magnitudes were small. It is concluded that the alpacas in the study present their own technological characteristics and the diameter profile configures a characteristic seasonal pattern coinciding with the rainfall seasonality of the Altiplano.Se determinaron las características tecnológicas y el perfil del diámetro de fibra según edad (1, 3, 5 y 7 años) y sexo (macho y hembra) de alpacas Huacaya del Centro Experimental La Raya (Puno, Perú). Se tomaron muestras de vellón del costillar medio al momento de la esquila y se analizaron con el equipo OFDA 2000. Los datos fueron ajustados a regresión múltiple cuadrática para el análisis de las tasas de cambio. El diámetro promedio, factor de confort, índice de curvatura y longitud de fibra fueron estadísticamente similares entre sexos, mientras que para la edad, el diámetro incrementó (de 19.48 ± 0.25 a 24.82 ± 0.80 µm), y disminuyó el factor de confort (de 98.15 a 86.95%) y la longitud de fibra (de 102.18 ± 12.92 a 75.00 ± 11.34 mm), mientras que el índice de curvatura no mostró tendencia definida. Los parámetros que caracterizan el perfil del diámetro de fibra mostraron un solo valor máximo del diámetro medio de fibra, que mostró una curva cóncava con dos segmentos ascendente y descendente. Las tasas de cambio fueron positivas y negativas, aunque sus magnitudes fueron pequeñas. Se concluye que las alpacas del estudio presentan características tecnológicas propias y el perfil del diámetro configura un patrón característico estacional coincidente con la estacionalidad pluvial del Altiplano

Niemann-Pick disease type-B: a unique case report with compound heterozygosity and complicated lipid management

BACKGROUND: Niemann-Pick disease (NPD) is a rare autosomal recessive hereditary disease characterized by deficient activity of acid sphingomyelinase. CASE PRESENTATION: We present a case of NPD type B with a unique compound heterozygosity for SMPD1 (NM_000543.4:c.[84delC];[96G¿>¿A]) in which both mutations that induce an early stop codon are located before the second in-frame initiation codon. The clinical presentation of the patient is compatible with NPD type B. She was initially diagnosed of Gaucher Disease, but her altered lipid profile led to a clinical suspicion of NPD. Combined high doses of atorvastatin and ezetimibe were given to treat the severe hypercholesterolemia. CONCLUSIONS: The pharmacological management of the lipid profile in these patients is important. A unique compound mutation in SMPD1 gene is described

Degassing at Sabancaya volcano measured by UV cameras and the NOVAC network

We used low-cost Raspberry Pi ultraviolet (UV) cameras to measure sulphur dioxide (SO2) fluxes from Sabancaya volcano, Peru, during eruptive activity on 27 April 2018. Light dilution corrections were made by operating instruments at two distances simultaneously. Estimated SO2 fluxes of 27.1 kgs-1 are higher than previously reported, likely due to the current eruptive episode (ongoing since November 2016). Each eruptive event included frequent (2–3 per minute), ash-rich emissions, forming gas pulses with masses of 3.0–8.2 tonnes SO2. Sustained degassing and lack of overpressure suggest open-vent activity. Mean fluxes are consistent with those measured by a permanent NOVAC station (25.9 kgs-1) located under the plume, with remaining differences likely due to windspeed estimates and sampling rate. Our work highlights the importance of accurate light dilution and windspeed modelling in SO2 retrievals and suggests that co-location of UV cameras with permanent scanning spectrometers may be valuable in providing accurate windspeeds

A new lizard of the Liolaemus montanus group that inhabits the hyperarid desert of southern Peru

A new lizard of the genus Liolaemus is described from the Tacna region of southern of Peru. This species belongs to the L. montanus group and was initially thought to be L. poconchilensis and L. insolitus. However, a series of diagnostic characters differentiate it consistently from these two species and all other species of the genus. To determine the taxonomic status of these lizards, their phylogenetic relationships were analyzed, as well as their morphological and ecological characteristics. The results of the analysis support the conclusion that this population of lizards represents a new species to science, and that the new species is related to L. nazca and L. chiribaya. The new species has sexual dimorphism and is known from elevations of ca. 1,000 m above sea level in the hyperarid Pacifc deserts, which are populated by scattered Ephedra americana and Poissonia sp. Due to its highly restricted range and observed habitat loss, we recommend this species be categorized as Critically EndangeredUna nueva especie de lagarto del género Liolaemus es descrita para la Región Tacna, sur de Perú. Esta especie pertenece al grupo L. montanus, la que fue inicialmente confundida con L. poconchilensis y L. insolitus. Sin embargo, una serie de caracteres diagnósticos la diferencian consistentemente de estas y otras especies del género. Para determinar su estatus taxonómico, nosotros analizamos sus relaciones filogenéticas, así como sus características morfológicas y ecológicas. Nuestros resultados sustentan la conclusión que esta población es una nueva especie para la Ciencia, e indica que esta nueva especie está relacionada a L. nazca and L. chiribaya. La nueva especie presenta dimorfismo sexual, y es conocida en elevaciones cercanas a los 1,000 m sobre el nivel del mar, en el hiperárido desierto del Pacífico con matorral de Ephedra americana y Poissonia sp. Debido a su distribución restringida y la pérdida de hábitat observada, nosotros proponemos que sea incluida en la lista de especies amenazadas como En Peligro Crítico.Fil: Valladares Faundez, John Pablo. Universidad de Tarapaca.; ChileFil: Franco León, Pablo. Universidad Jorge Basadre Grohmann; PerúFil: Chipana, César Jove. Universidad Nacional Jorge Basadre Grohmann.; PerúFil: Navarro Guzmán, Marco. Universidad Nacional Jorge Basadre Grohmann.; PerúFil: Apaza, Javier Ignacio. Universidad Jorge Basadre Grohmann; PerúFil: Cáceres Musaja, César. Universidad Jorge Basadre Grohmann; PerúFil: Langstroth, Robert. Colección Boliviana de Fauna; Bolivia. Universidad Mayor de San Andrés; BoliviaFil: Aguilar Kiriguin, Alvaro. Colección Boliviana de Fauna; BoliviaFil: Gutierrez, Roberto C.. Universidad Nacional de San Agustín. Facultad de Ciencias Biológicas. Departamento Académico de Biología. Museo de Historia Natural; PerúFil: Abdala, Cristian Simón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin

Big data and open data in education, evaluation of the scope of existing initiatives: case study Faculty of Technology and Applied Sciences of the National University of Catamarca

Data is the fuel of the 21st century. Increasingly our economies are driven by this input. Data has the potential to create social value, something that higher education institutions are beginning to rely on, as evidenced by the initiatives of public access to their data and the various advantages and benefits provided by big data in improving educational management, the development of customized curricula, monitoring the academic performance of students, as well as in the generation of digital repositories that are the product of years of academic, teaching and research activity. The present research aims to evaluate the scope of existing initiatives on the subject of Big Data and Open Data in education, in the Faculty of Technology and Applied Sciences of the National University of Catamarca (UNCA), producing an effective contribution with preliminary results for the research project called "ICT in the Service of Open Data: Current Situation, Conceptualization and Initiatives for Opening Public Information" which is being carried out in the Department of Informatics.Instituto de Investigación en Informátic

Fleece variation in alpaca (Vicugna pacos): a two-locus model for the Suri/Huacaya phenotype

Background: Genetic improvement of fibre-producing animal species has often induced transition from double coated to single coated fleece, accompanied by dramatic changes in skin follicles and hair composition, likely implying variation at multiple loci. Huacaya, the more common fleece phenotype in alpaca (Vicugna pacos), is characterized by a thick dense coat growing perpendicularly from the body, whereas the alternative rare and more prized single-coated Suri phenotype is distinguished by long silky fibre that grows parallel to the body and hangs in separate, distinctive pencil locks. A single-locus genetic model has been proposed for the Suri-Huacaya phenotype, where Huacaya is recessive. Results: Two reciprocal experimental test-crosses (Suri x Huacaya) were carried out, involving a total of 17 unrelated males and 149 unrelated females. An additional dataset of 587 offspring of Suri x Suri crosses was analyzed. Segregation ratios, population genotype frequencies, and/or recombination fraction under different genetic models were estimated by maximum likelihood. The single locus model for the Suri/Huacaya phenotype was rejected. In addition, we present two unexpected observations: 1) a large proportion (about 3/4) of the Suri animals are segregating (with at least one Huacaya offspring), even in breeding conditions where the Huacaya trait would have been almost eliminated; 2) a model with two different values of the segregation ratio fit the data significantly better than a model with a single parameter. Conclusions: The data support a genetic model in which two linked loci must simultaneously be homozygous for recessive alleles in order to produce the Huacaya phenotype. The estimated recombination rate between these loci was 0.099 (95% C. L. = 0.029-0.204). Our genetic analysis may be useful for other species whose breeding system produces mainly half-sib families