801 research outputs found
Implantes cortos una alternativa eficaz en implantología (revisión bibliográfica)
This paper is a review to the current literature about the possibility of place short implants as an alternative, forehead the possibility of previous surgery for alveolar remodeling bed, and the placement of long implants in the absence of bone. This will be analyzed factors such as type of bone, implant length and diameter, crown-root ratio, surface of the implant surgery and prosthetic loading phases.
Dental implants are a more conservative alternative to the replacement of lost tooth structure, but the decision to implement certain protocols requires a thorough analysis of each case, always considering a reverse planning as the best way to determine the protocol to be executed in certain cases.
The lack of alveolar bone, often constitutes a limiting factor in the treatment of implant placement, suggesting as previous protocol execution of the alveolar bed reshaping surgeries that require certain drawbacks especially the patient, it will increase one's time and inconvenience of surgery prior to the placement of dental implants, so that the possibility of short implants must be carefully analyzed and considered even the possibility of long implant placement in the absence of dental bone. Thus this work aims at using a systematic and thorough review will determine the feasibility of implementing the proposed treatment.El presente trabajo constituye una revisión a la literatura actual, sobre la posibilidad de colocar implantes cortos como alternativa, frente a la posibilidad de realizar cirugías previas para remodelación de lecho alveolar, y a la colocación de implantes largos en ausencia de hueso. Para lo cual serán analizados factores como el tipo de hueso, la longitud y diámetro del implante, índice corono-radicular, superficie del implante, fases quirúrgicas y carga protésica.
Los implantes dentarios constituyen una alternativa de lo mas conservadora para la reposición de estructuras dentales perdidas, sin embargo la decisión de ejecutar determinados protocolos exige un minucioso análisis de cada caso, considerando siempre una planificación reversa como la mejor manera para decidir el protocolo a ser ejecutado en determinados casos.
La ausencia de hueso alveolar, se constituye muchas veces en una limitante al tratamiento de colocación de implantes, sugiriendo como protocolo previo la ejecución de cirugías remodeladoras del lecho alveolar que exigen ciertos inconvenientes sobre todo al paciente, además de aumentar el tiempo y las propias molestias de una cirugía precedente a la colocación del implante dental, de tal manera que la posibilidad de colocación de implantes cortos debe ser minuciosamente analizada y considerada incluso sobre la posibilidad de colocación de implantes largos en ausencia de hueso dental.
De esta manera este trabajo pretende mediante una sistemática y minuciosa revisión determinara la factibilidad de ejecutar el tratamiento propuesto
Mundo, vocación cristiana y contemplación en la predicación francesa de Jean Gerson (1363-1429)
Reaching the millennium development goal for child mortality : improving equity and efficiency in Ecuador's health budget
health care; infant mortality; health policy;
Evaluation of cell culture in microfluidic chips for application in monoclonal antibody production
Microfluidic chips are useful devices for cell culture that allow cell growth under highly controlled conditions, as is required for production of therapeutic recombinant proteins. To understand the optimal conditions for growth of cells amenable of recombinant protein expression in these devices,we culturedHEK-293T cells under different microfluidic experimental conditions. The cells were cultured in polymethyl methacrylate (PMMA) and polydi-methylsiloxane (PDMS)microdevices, in the absence or presence of the cell adhesion agent poly-D-lysine. Different microchannel geometries and thicknesses, as well as the influence of the flow rate have also been tested, showing their great influence in cell adhesion and growth. Results show that the presence of poly-D-lysine improves the adhesion and viability of the cells in continuous or discontinuous flow. Moreover, the optimal adhesion of cells was observed in the corners of themicrochannels, as well as in wide channels possibly due to the decrease in the flow rate in these areas. These studies provide insight into the optimal architecture of microchannels for long-term culture of adherent cells in order to use microfluidics devices as bioreactors for monoclonal antibodies production.Fil: Peñaherrera Pazmiño, Ana Belén. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Payés, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sierra Rodero, Marina. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vega, M.. Universidad Tecnológica Nacional; ArgentinaFil: Rosero, G.. Universidad Tecnológica Nacional; Argentina. Universidad de Buenos Aires; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional; Argentina. Universidad de Buenos Aires; ArgentinaFil: Helguera, Gustavo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Pérez, M. S.. Universidad Tecnológica Nacional; Argentina. Universidad de Buenos Aires; Argentin
Three phases microextraction procedure for determination of isothiazolin biocides in adhesives for food packaging materials
The use of biocides in adhesives is widely extended. However, when adhesives are used in food packaging materials, it is important to determine their concentration not only in the packaging materials but also in migration tests, in order to ensure the food safety. Isothiazolin derivatives are low volatile compounds and often used for this purpose. However, the analytical sensitivity is very poor either in GC-MS or in HPLC-UV and an enrichment step is required. The present study deals with the development of a liquid microextraction procedure for enhancing the sensitivity of the determination of 2-methyl-4-isothiazolin-3-one (MIT) and 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) in adhesives and food simulants. The procedure involves three phases and a semipermeable polypropylene (PP) membrane which contains 1-octanol as organic phase. The donor and acceptor phases are aqueous acidic and alkaline media respectively and the final liquid phase is analyzed by RP-HPLC-UV. The detection limits of these biocides are 0.037 and 0.147 μg g-1 for MIT and CMIT respectively. Three different adhesive samples were successfully analyzed. The procedure was compared with the direct analysis using UPLC-Q-TOF, where the identification of the compounds and the quantification values were confirmed. The results obtained are shown and discussed
Deep neural network for load forecasting centred on architecture evolution
Nowadays, electricity demand forecasting is critical for electric utility companies. Accurate residential load forecasting plays an essential role as an individual component for integrated areas such as neighborhood load consumption. Short-term load forecasting can help electric utility companies reduce waste because electric power is expensive to store. This paper proposes a novel method to evolve deep neural networks for time series forecasting applied to residential load forecasting. The approach centres its efforts on the neural network architecture during the evolution. Then, the model weights are adjusted using an evolutionary optimization technique to tune the model performance automatically. Experimental results on a large dataset containing hourly load consumption of a residence in London, Ontario shows that the performance of unadjusted weights architecture is comparable to other state-of-the-art approaches. Furthermore, when the architecture weights are adjusted the model accuracy surpassed the state-of-the-art method called LSTM one shot by 3.0%
Transfer Learning by Similarity Centred Architecture Evolution for Multiple Residential Load Forecasting
The development from traditional low voltage grids to smart systems has become extensive and adopted worldwide. Expanding the demand response program to cover the residential sector raises a wide range of challenges. Short term load forecasting for residential consumers in a neighbourhood could lead to a better understanding of low voltage consumption behaviour. Nevertheless, users with similar characteristics can present diversity in consumption patterns. Consequently, transfer learning methods have become a useful tool to tackle differences among residential time series. This paper proposes a method combining evolutionary algorithms for neural architecture search with transfer learning to perform short term load forecasting in a neighbourhood with multiple household load consumption. The approach centres its efforts on neural architecture search using evolutionary algorithms. The neural architecture evolution process retains the patterns of the centre-most house, and later the architecture weights are adjusted for each house in a multihouse set from a neighbourhood. In addition, a sensitivity analysis was conducted to ensure model performance. Experimental results on a large dataset containing hourly load consumption for ten houses in London, Ontario showed that the performance of the proposed approach performs better than the compared techniques. Moreover, the proposed method presents the average accuracy performance of 3.17 points higher than the state-of-the-art LSTM one shot method
Critical Repetition Rates for Perceptual Segregation of Time-Varying Auditory, Visual and Vibrotactile Stimulation
What sound quality has led to exclude infrasound from sound in the conventional hearing range? We examined whether temporal segregation of pressure pulses is a distinctive property and evaluated this perceptual limit via an adaptive psychophysical procedure for pure tones and carriers of different envelopes. Further, to examine across-domain similarity and individual covariation of this limit, here called the critical segregation rate (CSR), it was also measured for various periodic visual and vibrotactile stimuli. Results showed that sequential auditory or vibrotactile stimuli separated by at least ~80‒90 ms (~11‒12-Hz repetition rates), will be perceived as perceptually segregated from one another. While this limit did not statistically differ between these two modalities, it was significantly lower than the ~150 ms necessary to perceptually segregate successive visual stimuli. For the three sensory modalities, stimulus periodicity was the main factor determining the CSR, which apparently reflects neural recovery times of the different sensory systems. Among all experimental conditions, significant within- and across-modality individual CSR correlations were observed, despite the visual CSR (mean: 6.8 Hz) being significantly lower than that of both other modalities. The auditory CSR was found to be significantly lower than the frequency above which sinusoids start to elicit a tonal quality (19 Hz; recently published for the same subjects). Returning to our initial question, the latter suggests that the cessation of tonal quality — not the segregation of pressure fluctuations — is the perceptual quality that has led to exclude infrasound (sound with frequencies < 20 Hz) from the conventional hearing range
Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: I. VLA Observations
We present a high sensitivity radio continuum survey at 6 and 1.3cm using
the Karl G. Jansky Very Large Array towards a sample of 58 high-mass star
forming regions. Our sample was chosen from dust clumps within infrared dark
clouds with and without IR sources (CMC-IRs, CMCs, respectively), and hot
molecular cores (HMCs), with no previous, or relatively weak radio continuum
detection at the mJy level. Due to the improvement in the continuum
sensitivity of the VLA, this survey achieved map rms levels of 3-10
Jy beam at sub-arcsecond angular resolution. We extracted 70
centimeter continuum sources associated with 1.2mm dust clumps. Most
sources are weak, compact, and are prime candidates for high-mass protostars.
Detection rates of radio sources associated with the mm dust clumps for CMCs,
CMC-IRs and HMCs are 6, 53 and 100, respectively. This result is
consistent with increasing high-mass star formation activity from CMCs to HMCs.
The radio sources located within HMCs and CMC-IRs occur close to the dust clump
centers with a median offset from it of 12,000AU and 4,000AU,
respectively. We calculated 5 - 25GHz spectral indices using power law fits
and obtain a median value of 0.5 (i.e., flux increasing with frequency),
suggestive of thermal emission from ionized jets. In this paper we describe the
sample, observations, and detections. The analysis and discussion will be
presented in Paper II.Comment: Accepted for publication in the ApJ
- …