121 research outputs found

    Morphometric and chemical characterization of bone grafting particles used in guided bone regeneration

    Get PDF
    Objetivos: Realizar un análisis morfométrico y químico de distintas partículas óseas de relleno utilizadas para tratamientos de regeneración ósea guiada en odontología. Métodos: Se analizaron distintas partículas óseas comerciales de origen alogénico (OS, UNC y MO), xenogénico (BO) y aloplástico (GP). Se utilizó como control tejido óseo obtenido de cirugía de dientes retenidos. Para el análisis morfométrico se analizaron las partículas óseas con lupa estereoscópica y se determinó el tamaño medio de las mismas. En el análisis químico se utilizó el microanálisis por energía dispersiva de rayos X (EPXMA). Para ello las muestras fueron criodesecadas, recubiertas en carbón y analizadas en un microscopio electrónico de barrido con el fin de determinar en forma cuantitativa (mmol/kg) los elementos de Ca y P. Asimismo, se determinó la relación Ca/P de cada grupo experimental. Resultados: El análisis morfométrico mostró que los tamaños medios de partículas óseas (mm) en orden creciente fue: UNC: 0,45; OS: 0,48; BO: 0,65; GP: 0,76; MO: 0,88. Cuando realizamos el análisis microanalítico observamos que todas las partículas óseas de relleno poseían una concentración de Ca menor al control. Por otra parte, MO presentó una concentración de P estadísticamente superior con respecto a las demás partículas óseas y al control. La relación Ca/P mostró ser estadísticamente menor en MO con respecto a los demás grupos experimentales. Conclusiones: La caracterización morfológica y química de las partículas óseas de relleno permitió conocer con mayor precisión el tamaño de las partículas óseas así como la concentración de Ca y P presente en las mismas, datos que utilizados junto a otras valoraciones clínicas permitiría obtener un tratamiento de regeneración ósea guiada más efectivo en odontología.Purpose: To perform a morphometric and chemical analysis of different bone graft materials used for guided bone regeneration treatments in dentistry. Methods: allogenic bone graft (OS, UNC and MO), xenogenic bone graft (BO) and alloplastic bone graft (GP), were analyzed. The bone tissue obtained from retained teeth surgery was used as a control. The morphometric analysis of particles was performed by using a stereoscopic magnifying glass and the average particle size was determined. Besides, X-ray dispersive energy microanalysis (EPXMA) was used in the chemical analysis. Bone graft particles were freeze dried, coated with carbon and analyzed in a scanning electron microscope in order to quantitatively determine (mmol/kg) the elements Ca and P. Ca/P ratio was determined for each experimental group. Results: Morphometric analysis showed that the mean bone particle size (mm) in increasing order was: UNC: 0.45; OS: 0.48; BO: 0.65; GP: 0.76; MO: 0.88. Microanalytical analysis showed that the Ca concentration in different experimental groups is less than the control. On the other hand, MO presented a statistically higher concentration of P than the other particles and the control. Ca/P ratio was statistically lower in MO c ompared to the other experimental groups. Conclusions: The morphological and chemical characterization of the bone particles allowed to know with greater precision the particle size, as well as the concentration of Ca and P present in them, data that should be used together with other clinical evaluations for guided bone regeneration treatments in dentistry

    Slow Roll Reconstruction: Constraints on Inflation from the 3 Year WMAP Dataset

    Get PDF
    We study the constraints on the inflationary parameter space derived from the 3 year WMAP dataset using ``slow roll reconstruction'', using the SDSS galaxy power spectrum to gain further leverage where appropriate. This approach inserts the inflationary slow roll parameters directly into a Monte Carlo Markov chain estimate of the cosmological parameters, and uses the inflationary flow hierarchy to compute the parameters' scale-dependence. We work with the first three parameters (epsilon, eta and xi) and pay close attention to the possibility that the 3 year WMAP dataset contains evidence for a ``running'' spectral index, which is dominated by the xi term. Mirroring the WMAP team's analysis we find that the permitted distribution of xi is broad, and centered away from zero. However, when we require that inflationary parameters yield at least 30 additional e-folds of inflation after the largest observable scales leave the horizon, the bounds on xi tighten dramatically. We make use of the absence of an explicit pivot scale in the slow roll reconstruction formalism to determine the dependence of the computed parameter distributions on the pivot. We show that the choice of pivot has a significant effect on the inferred constraints on the inflationary variables, and the spectral index and running derived from them. Finally, we argue that the next round of cosmological data can be expected to place very stringent constraints on the region of parameter space open to single field models of slow roll inflation.Comment: 26 pages, 11 figures, JHEP format. v2: version accepted by JCAP: minor clarifications and references added, 1 figure added, v3: 1 reference adde

    Big Data Analytics for Earth Sciences: the EarthServer approach

    Get PDF
    Big Data Analytics is an emerging field since massive storage and computing capabilities have been made available by advanced e-infrastructures. Earth and Environmental sciences are likely to benefit from Big Data Analytics techniques supporting the processing of the large number of Earth Observation datasets currently acquired and generated through observations and simulations. However, Earth Science data and applications present specificities in terms of relevance of the geospatial information, wide heterogeneity of data models and formats, and complexity of processing. Therefore, Big Earth Data Analytics requires specifically tailored techniques and tools. The EarthServer Big Earth Data Analytics engine offers a solution for coverage-type datasets, built around a high performance array database technology, and the adoption and enhancement of standards for service interaction (OGC WCS and WCPS). The EarthServer solution, led by the collection of requirements from scientific communities and international initiatives, provides a holistic approach that ranges from query languages and scalability up to mobile access and visualization. The result is demonstrated and validated through the development of lighthouse applications in the Marine, Geology, Atmospheric, Planetary and Cryospheric science domains

    Design, data management, and population baseline characteristics of the PERFORM magnetic resonance imaging project

    Get PDF
    Quantitative information from magnetic resonance imaging (MRI) may substantiate clinical findings and provide additional insight into the mechanism of clinical interventions in therapeutic stroke trials. The PERFORM study is exploring the efficacy of terutroban versus aspirin for secondary prevention in patients with a history of ischemic stroke. We report on the design of an exploratory longitudinal MRI follow-up study that was performed in a subgroup of the PERFORM trial. An international multi-centre longitudinal follow-up MRI study was designed for different MR systems employing safety and efficacy readouts: new T2 lesions, new DWI lesions, whole brain volume change, hippocampal volume change, changes in tissue microstructure as depicted by mean diffusivity and fractional anisotropy, vessel patency on MR angiography, and the presence of and development of new microbleeds. A total of 1,056 patients (men and women ≥55 years) were included. The data analysis included 3D reformation, image registration of different contrasts, tissue segmentation, and automated lesion detection. This large international multi-centre study demonstrates how new MRI readouts can be used to provide key information on the evolution of cerebral tissue lesions and within the macrovasculature after atherothrombotic stroke in a large sample of patients

    Molecular analysis of the vaginal response to estrogens in the ovariectomized rat and postmenopausal woman

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Vaginal atrophy (VA) is the thinning of the vaginal epithelial lining, typically the result of lowered estrogen levels during menopause. Some of the consequences of VA include increased susceptibility to bacterial infection, pain during sexual intercourse, and vaginal burning or itching. Although estrogen treatment is highly effective, alternative therapies are also desired for women who are not candidates for post-menopausal hormone therapy (HT). The ovariectomized (OVX) rat is widely accepted as an appropriate animal model for many estrogen-dependent responses in humans; however, since reproductive biology can vary significantly between mammalian systems, this study examined how well the OVX rat recapitulates human biology.</p> <p>Methods</p> <p>We analyzed 19 vaginal biopsies from human subjects pre and post 3-month 17β-estradiol treated by expression profiling. Data were compared to transcriptional profiling generated from vaginal samples obtained from ovariectomized rats treated with 17β-estradiol for 6 hrs, 3 days or 5 days. The level of differential expression between pre- vs. post- estrogen treatment was calculated for each of the human and OVX rat datasets. Probe sets corresponding to orthologous rat and human genes were mapped to each other using NCBI Homologene.</p> <p>Results</p> <p>A positive correlation was observed between the rat and human responses to estrogen. Genes belonging to several biological pathways and GO categories were similarly differentially expressed in rat and human. A large number of the coordinately regulated biological processes are already known to be involved in human VA, such as inflammation, epithelial development, and EGF pathway activation.</p> <p>Conclusion</p> <p>At the transcriptional level, there is evidence of significant overlap of the effects of estrogen treatment between the OVX rat and human VA samples.</p

    Rationale, design and population baseline characteristics of the PERFORM Vascular Project: an ancillary study of the Prevention of cerebrovascular and cardiovascular Events of ischemic origin with teRutroban in patients with a history oF ischemic strOke or tRansient ischeMic attack (PERFORM) trial

    Get PDF
    &lt;p&gt;&lt;b&gt;Purpose&lt;/b&gt;&lt;/p&gt; &lt;p&gt;PERFORM is exploring the efficacy of terutroban versus aspirin for secondary prevention in patients with a history of ischemic stroke or transient ischemic attacks (TIAs). The PERFORM Vascular Project will evaluate the effect of terutroban on progression of atherosclerosis, as assessed by change in carotid intima-media thickness (CIMT) in a subgroup of patients.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods and results&lt;/b&gt;&lt;/p&gt; &lt;p&gt;The Vascular Project includes structural (CIMT, carotid plaques) and functional (carotid stiffness) vascular studies in all patients showing at least one carotid plaque at entry. Expected mean follow-up is 36 months. Primary endpoint is rate of change of CIMT. Secondary endpoints include emergent plaques and assessment of carotid stiffness. 1,100 patients are required for 90% statistical power to detect treatment-related CIMT difference of 0.025 mm. The first patient was randomized in April 2006.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions&lt;/b&gt;&lt;/p&gt; &lt;p&gt;The PERFORM Vascular Project will investigate terutroban’s effect on vascular structure and function in patients with a history of ischemic stroke or TIAs.&lt;/p&gt

    Large Non-Gaussianities in Single Field Inflation

    Get PDF
    We compute the 3-point correlation function for a general model of inflation driven by a single, minimally coupled scalar field. Our approach is based on the numerical evaluation of both the perturbation equations and the integrals which contribute to the 3-point function. Consequently, we can analyze models where the potential has a "feature", in the vicinity of which the slow roll parameters may take on large, transient values. This introduces both scale and shape dependent non-Gaussianities into the primordial perturbations. As an example of our methodology, we examine the ``step'' potentials which have been invoked to improve the fit to the glitch in the ClC_l for l30l \sim 30, present in both the one and three year WMAP data sets. We show that for the typical parameter values, the non-Gaussianities associated with the step are far larger than those in standard slow roll inflation, and may even be within reach of a next generation CMB experiment such as Planck. More generally, we use this example to explain that while adding features to potential can improve the fit to the 2-point function, these are generically associated with a greatly enhanced signal at the 3-point level. Moreover, this 3-point signal will have a very nontrivial shape and scale dependence, which is correlated with the form of the 2-point function, and may thus lead to a consistency check on the models of inflation with non-smooth potentials.Comment: 23 pages JHEP-style, 7 Figures. Updated with improved results. Accepted for publication by JCA

    Myometrium of the spiny dogfish Squalus acanthias: peptide and steroid regulation

    No full text
    corecore