227 research outputs found
Enamel pearl associated with localized periodontitis in Hellenistic age woman
Tooth anatomic factors like ectopic enamel pearls are often associated with localized periodontal inflammation and bone loss. There are no existing paleopathological data for such structural anomalies in ancient populations associated with periodontal pathology in the literature. A rare case of enamel pearl on the maxillary right first molar of women associated with localized periodontitis is presented and discussed
Enamel pearl associated with localized periodontitis in Hellenistic age woman
Tooth anatomic factors like ectopic enamel pearls are often associated with localized periodontal inflammation and bone loss. There are no existing paleopathological data for such structural anomalies in ancient populations associated with periodontal pathology in the literature. A rare case of enamel pearl on the maxillary right first molar of women associated with localized periodontitis is presented and discussed
An alternative differential method of femtosecond pump-probe examination of materials
We describe an alternative method for femtosecond pumpprobe beam examination of energy transport properties of materials. All already reported techniques have several drawbacks which limit precise measurements of reflection coefficient as function of time. A typical problem is present when rough samples are being studied. In this case the pump-beam polarization changes randomly which may produce a spurious signal, drastically reducing the signal to noise ratio. Some proposals to alleviate such problema have been reported, however, they have not been totally satisfactory. The method presented here consists on measuring the difference between the two delays’ signals of the probe-beam. As will be explained, our proposal is free of typical drawbacks. We also propose a numerical method to recover the DR(t)/R curve from the measured data. Numerical simulations show that our proposal is a viable alternative
HPLC detection of dehydroepiandrosterone in food additives by using normal phase HPLC
A normal-phase High Performance Liquid Chromatography (HPLC) method was developed for the determination of dehydroepiandrosterone (DHEA) in food supplements. We have used an HPLC 200 (Perkin Elmer, USA) with a spectrophotometric detector LC-785A (Bioanalytical systems, USA) and a thermostat (Perkin Elmer, Waltham, MA, USA). We have chosen isocratic HPLC elution, column: LiChrospher (100 DIOL 250 x 4 mm х 5 μm), mobile phase: acetonitrile: water = 98: 2 v/v, flow rate: 1 ml/min. and detection at λ = 202 nm. We have found that this method allows fast and selective qualitative and quantitative determination of DHEA in pharmaceutical products
Foucault test: shadowgram modeling from the physical theory for quantitative evaluations
The physical theory of the Foucault test has been investigated to represent the complex amplitude and irradiance of the shadowgram in terms of the wavefront error; however, most of the studies have limited the treatment for the particular case of nearly diffraction-limited optical devices (i.e., aberrations smaller than the wavelength). In this paper we discard this restriction, and in order to show a more precise interpretation from the physical theory we derive expressions for the complex amplitude and the irradiance over an optical device with larger aberrations. To the best of our knowledge, it is the first time an expression is obtained in closed form. As will be seen, the result of this derivation is obtained using some properties of the Hilbert transform that permit representing the irradiance in a simple form in terms of the partial derivatives of the wavefront error. Additionally, we briefly describe from this point of view a methodology for the quantitative analysis of the test
The 2D Continuous Wavelet Transform: Applications in Fringe Pattern Processing for Optical Measurement Techniques
Optical metrology and interferometry are widely known disciplines that study and develop techniques to measure physical quantities such as dimensions, force, temperature, stress, etc. A key part of these disciplines is the processing of interferograms, also called fringe patterns. Owing that this kind of images contains the information of interest in a codified form, processing them is of main relevance and has been a widely studied topic for many years. Several mathematical tools have been used to analyze fringe patterns, from the classic Fourier analysis to regularization methods. Some methods based on wavelet theory have been proposed for this purpose in the last years and have evidenced virtues to consider them as a good alternative for fringe pattern analysis. In this chapter, we resume the theoretical basis of fringe pattern image formation and processing, and some of the most relevant applications of the 2D continuous wavelet transform (CWT) in fringe pattern analysis
Le Traitement Antibiotique Dans La PĂ©diatrie
The current study should be paid extra attention because antibiotics are main cluster of drugs for treatment of child infections and illnesses. They are the most commonly prescribed medicines for children, relatively expensive and consume 60-70% of the budget for treatment of child illnesses, with exclusion only in malign sickness. OBJECT: The current study represents common classification of antibiotics and the most commonly used antimicrobial agents during childhood. RESEARCH METHODS - Systematic approach and critical analysis of the available scientific periodicals - Interview method of the survey (survey data pediatricians and general practitioners in the region of Plovdiv, Bulgaria.) - Own research on the issue. RESULTS AND DISCUSSION: Most often, doctors use: Broad-spectrum penicillins: Amoxicillin, Amopen, Ospamox, Duomox First generation cephalosporins: Ospexin, Cephalexin Second-generation cephalosporins: Cefaclor Third generation cephalosporins: Abricef, Cefotaxime, Rocephin, Fortum Fourth generation cephalosporins: Maxipime Macrolides: Macropen Aminoglycosides: Gentamicin, Amicacine CONCLUSION: No significant differences are observed in the prescribed by the general practitioners and pediatricians antibiotics
MAP entropy estimation: Applications in robust image filtering
We introduce a new approach for image filtering in a Bayesian framework. In this case the probability density function (pdf) of the likelihood function is approximated using the concept of non-parametric or kernel estimation. The method is based on the generalized
Gaussian Markov random fields (GGMRF), a class of Markov random fields which are used as prior information into the Bayesian rule, which principal objective is to eliminate those effects caused by the excessive smoothness on the reconstruction process of images which are rich in contours or edges. Accordingly to the hypothesis made for the present work, it is assumed a limited knowledge of the noise pdf, so the idea is to use a non-parametric estimator to estimate such a pdf and then apply the entropy to construct the cost function for the likelihood term. The previous idea leads to the construction of Maximum a posteriori (MAP) robust estimators, since the real systems are always exposed to continuous perturbations of unknown nature. Some promising results of three new MAP entropy estimators (MAPEE) for image filtering are presented, together with some concluding remarks
Chlorophyll fluorescence emission of tomato plants as a response to pulsed light based LEDs
The effects of pulsed light based-LEDs at eleven
frequencies (0.1, 1, 10, 50, 100, 500 Hz, 1, 5, 10, 50
and 100 kHz) programmed at 50 % duty cycle were analyzed,
obtaining important parameters of the fluorescence
emission of chlorophyll such as: maximum fluorescence
(Fm0), minimum fluorescence, the fluorescence emission in
steady state, maximum efficiency of PSII (Fv0/Fm0), the
fraction of PSII centers that are open, photochemical
quenching, nonphotochemical quenching (NPQ), quantum
efficiency of photosystem II (UPSII), electron transport
rate (ETR) and quantum yield of CO2 assimilation (/CO2).
For the study and validation of the results obtained in the
experiments, the analysis of variance (ANOVA) was
applied 0for each parameter with confidence intervals of
95 %. The results show that the frequencies of pulsed light
had positive and negative effects on the fluorescence
parameters with respect to the control treatment (continuous
light). The frequencies that generated the best performance
of Fv0/Fm0, NPQ, UPSII, ETR, /CO2 in tomato
plants were 0.1, 1, 100 Hz, and 1 kHz. The increase
obtained in these parameters can represent an optimal
growth and productivity conditions for optimal energy
consumption
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