Titanium Oxide: A Bioactive Factor in Osteoblast Differentiation

Titanium and titanium alloys are currently accepted as the gold standard in dental applications. Their excellent biocompatibility has been attributed to the inert titanium surface through the formation of a thin native oxide which has been correlated to the excellent corrosion resistance of this material in body fluids. Whether this titanium oxide layer is essential to the outstanding biocompatibility of titanium surfaces in orthopedic biomaterial applications is still a moot point. To study this critical aspect further, human fetal osteoblasts were cultured on thermally oxidized and microarc oxidized (MAO) surfaces and cell differentiation, a key indicator in bone tissue growth, was quantified by measuring the expression of alkaline phosphatase (ALP) using a commercial assay kit. Cell attachment was similar on all the oxidized surfaces although ALP expression was highest on the oxidized titanium alloy surfaces. Untreated titanium alloy surfaces showed a distinctly lower degree of ALP activity. This indicates that titanium oxide clearly upregulates ALP expression in human fetal osteoblasts and may be a key bioactive factor that causes the excellent biocompatibility of titanium alloys. This result may make it imperative to incorporate titanium oxide in all hard tissue applications involving titanium and other alloys

Eficacia de la intervencion periodontal en el producto del embarazo en mujeres con pre-eclampsia

Objective: To determine the efficacy of periodontal intervention on pregnancy outcome in mild preeclamptic women. Methods: A sample of 60 pregnant women with mild preeclampsia (blood pressure levels <160/110 mm and proteinuria >300 mg/l in 24 hours urine) from the Hospital Universitario del Valle (Cali, Colombia) was included to the study. Preeclamptic women were randomized in two groups, one with periodontal intervention (PIG, N=28) and another in which the periodontal intervention was practiced after childbirth (NPIG, N=32). Maternal socio-demographic, medical and periodontal data were obtained. PIG included patients in which supragingival and subgingival cleaning within ultrasonic and manual devices were performed after study inclusion. The progression from mild to severe preeclampsia, eclampsia or HELLP syndrome, the number of days of clinical stability and the percentile of birth-weight adjusted for gestational age were evaluated in both groups. Results: Most of the patients (60%) were multigravids. Gestational age at inclusion was 31.8±1.6 weeks. Chronic periodontitis was a frequent finding (61.7%). Social, demographic, medical and periodontal conditions were similar between both groups. Disease progression to severe preeclampsia, eclampsia or HELLP syndrome was also similar (89.2% PIG versus 84.4%, p=0.65) (OR=1.06 IC 95% 0.87-1.29, p=0.65). Days of clinical stability were similar between the groups (median 10 days , range 1-46, PIG versus 12 days, range 1-59, p=0.57) and the percentile of birth weight adjusted with gestational age had no differences between the groups (median percentil 50 range 5-90 PIG versus percentil 55 range 5-95, p=0.73). Conclusion: Periodontal intervention does not seem to harm the health, the severity or alter the frequency on maternal complications in mild preeclampsia subjects. Objetivo: Determinar la eficacia y seguridad de la intervención periodontal sobre el producto del embarazo en gestantes hospitalizadas con diagnóstico de pre-eclampsia sin complicaciones. Métodos: En un ensayo clínico controlado se evaluaron 60 mujeres embarazadas con diagnóstico de pre-eclampsia leve (presión arterial 300mg/ l en orina de 24 horas), que se trataron en la unidad de alto riesgo obstétrico del Hospital Universitario del Valle (Cali, Colombia). Se evaluaron las características socio-demográficas, así como los aspectos médicos y periodontales. De este conjunto 28 (46.7%) gestantes se incluyeron al azar en el grupo con intervención periodontal anteparto (GIP) y 32 (53.3%) en el grupo sin intervención periodontal (GNIP). El análisis se hizo de acuerdo con la intención de tratamiento. La variable dependiente fue la proporción de mujeres que agravaron su condición pre-eclámptica hacia pre-eclampsia severa, eclampsia o síndrome de HELLP, el número de días de estabilidad clínica y el percentil de peso del recién nacido ajustado para la edad de la gestación. Resultados: De las pacientes 60% eran multíparas. La edad gestacional promedio de ingreso al estudio fue 31.8 semanas. El diagnóstico periodontal más frecuente fue periodontitis crónica (61.7%). Las características socio-demográficas, obstétricas y periodontales fueron afines en ambos grupos. La pre-eclampsia se agravó de manera comparable en los dos grupos (GIP 89.2% versus GNIP 84.4%, p=0.65) (OR=1.06 IC 95% 0.87-1.29, p=0.65). La estabilidad clínica en días, fue parecida en ambos grupos (GIP mediana 10 días, rango 1-46 versus GNIP 12 días, rango 1-59, p=0.57). La mediana del peso del recién nacido ajustado por la edad gestacional fue semejante en los dos grupos (GIP percentil 50, rango 5-90 versus GNIP percentil 53 rango 5-95, p=0.73). Conclusiones: El tratamiento periodontal en mujeres con pre-eclampsia no complicada no incrementa la severidad o frecuencia de las complicaciones maternas

Tuning up Fuzzy Inference Systems by using optimization algorithms for the classification of solar flares

In this work we describe the implementation and analysis of different optimization algorithms used for finding the best set of parameters for a Fuzzy Inference System intended to classify solar flares. The parameters will be identified among a universe of possible solutions for the algorithms, and the system will be tested in the particular case of dealing with the aim of classifying the solar flares.Comment: 14 pages, 2 figures, 18 tables. Accepted for publication in TECCIENCI

Serendipitous discovery of RR Lyrae stars in the Leo V ultra-faint galaxy

During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 +/- 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RR Lyrae stars. This serendipitous discovery shows that distant RR Lyrae stars may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.Comment: Accepted in ApJ Letter

MOGEDA : Modelo Genérico de Desensamblado Automático

El desensamblado de productos es la clave del proceso de reciclado. En este artículo se plantea el modelado del proceso de desensamblado automático de productos. Se estudian, tanto los requerimientos necesarios para poder abordar el proceso de forma automática, como las herramientas necesarias para poderlo llevar a cabo: base de conocimiento basada en modelos y técnicas de reconocimiento y localización tridimensional de objetos mediante visión artificial.Tanto los trabajos realizados como los futuros están enmarcados en el proyecto de la CICYT “Sistema Robotizado de Desensamblado Automático basado en Modelos y Visión Artificial” (TAP1999-0436)

Influence of ball milling on CaO crystal growth during limestone and dolomite calcination: Effect on CO2 capture at Calcium Looping conditions

The multicycle CO2 capture performance of CaO derived from the calcination of ball-milled limestone and dolomite have been tested under high temperature and high CO2 concentration environment for the first time. Here it is shown that the CO2 capture capacity of CaO is inversely related to the milling power applied to the starting mineral and the size of nascent CaO nanocrystals. In situ X-ray diffraction analysis used to follow the average crystallite size of CaCO3 and CaO during the calcination process as a function of temperature demonstrates that crystal growth is notably enhanced in a CO2-rich atmosphere for milled sorbents. Contrary to early reports suggesting improved reactivity towards carbonation of CaO from milled sorbents, promoted agglomeration, and crystal growth under these more “realistic” conditions lead to a severe deterioration of both capture capacity and recyclability, as observed from the multicyclic carbonation/calcination experiments. Yet the negative effect of milling is less pronounced in dolomite due to the constrained sintering effect of the inert MgO grains that results in smaller CaO crystallite sizes, reduced crystal growth rate, and improved performance. These results provide insight on the role of CaO crystallinity on the carbonation reaction, useful for devising strategies to improve sorbents performance.Peer reviewe

Optimal Nitrogen Fertilization to Reach the Maximum Grain and Stover Yields of Maize (Zea mays L.): Tendency Modeling

Utilization of maize stover to the production of meat and milk and saving the grains for human consumption would be one strategy for the optimal usage of resources. Variance and tendency analyses were applied to find the optimal nitrogen (N) fertilization dose (0, 100, 145, 190, 240, and 290 kg/ha) for forage (F), stover (S), cob (C), and grain (G) yields, as well as the optimal grain-to-forage, cob-to-forage, and cob-to-stover ratios (G:F, C:F, and C:S, respectively). The study was performed in central Mexico (20.691389° N and −101.259722° W, 1740 m a.m.s.l.; Cwa (Köppen), 699 mm annual precipitation; alluvial soils). N-190 and N-240 improved the individual yields and ratios the most. Linear and quadratic models for CDM, GDM, and G:F ratio had coefficients of determination (R2) of 0.20–0.46 (p < 0.03). Cubic showed R2 = 0.30–0.72 (p < 0.02), and the best models were for CDM, GDM, and the G:F, C:F, and C:S DM ratios (R2 = 0.60–0.72; p < 0.0002). Neither SHB nor SDM negatively correlated with CDM or GDM (r = 0.23–0.48; p < 0.0001). Excess of N had negative effects on forage, stover, cobs, and grains yields, but optimal N fertilization increased the proportion of the G:F, C:F, and C:S ratios, as well as the SHB and SDM yields, without negative effects on grain production

Towards a more accurate characterization of granular media 2.0: Involving AI in the process

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VISUAL : herramienta para la enseñanza práctica de la visión artificial

En este artículo se presenta un enfoque práctico para la enseñanza de la visión artificial en la asignatura de “Robots y Sistemas Sensoriales” impartida por el área de Ingeniería de Sistemas y Automática en la Universidad de Alicante. En primer lugar, se describe la herramienta VISUAL que ha sido desarrollada por miembros del grupo de Automático, Robótica y Visión Artificial y que permite al alumno especificar un algoritmo de procesamiento de imágenes mediante un esquema gráfico formado por un conjunto de diferentes módulos básicos de procesamiento. Así, la herramienta VISUAL proporciona un interfaz para la visión artificial de manejo intuitivo, al mismo tiempo que permite desarrollos de algoritmos fácilmente comprensibles gracias a su escalabilidad y modularidad, posibilitando realizar etapas de procesamiento claramente definidas. Además, se comentan algunos de los experimentos prácticos propuestos y desarrollados haciendo uso de VISUAL y destinados al reconocimiento y localización de objetos para su posterior manipulación con un robot

Virtual remote laboratory for teaching of computer vision and robotics in the University of Alicante

Comunicación presentada en IBCE'04, Second IFAC Workshop on Internet Based Control Education, 5-7 septiembre 2004, Grenoble, FranciaIn this article, we describe the virtual and remote laboratory for computer vision and robotics education at the University of Alicante (Spain). Its aims are to provide access for all the students to the available robotic and computer vision equipments, generally limited, due to its high cost