The timing of the first embryonic cell divisions may predict the ability of an embryo to establish pregnancy. Similarly, metabolic profiles may be markers of embryonic viability. However, in bovine, data about the metabolomics profile of these embryos are still not available. In the present work, we describe Raman-based metabolomic profiles of culture media of bovine embryos with different developmental kinetics (fast x slow) throughout the in vitro culture. The principal component analysis enabled us to classify embryos with different developmental kinetics since they presented specific spectroscopic profiles for each evaluated time point. We noticed that bands at 1076 cm−1 (lipids), 1300 cm−1 (Amide III), and 2719 cm−1 (DNA nitrogen bases) gave the most relevant spectral features, enabling the separation between fast and slow groups. Bands at 1001 cm−1 (phenylalanine) and 2892 cm−1 (methylene group of the polymethylene chain) presented specific patterns related to embryonic stage and can be considered as biomarkers of embryonic development by Raman spectroscopy. The culture media analysis by Raman spectroscopy proved to be a simple and sensitive technique that can be applied with high efficiency to characterize the profiles of in vitro produced bovine embryos with different development kinetics and different stages of development.
The objectives of this study were to evaluate the effect of low-level laser irradiation (LLLI) on bovine oocyte and granulosa cells metabolism during in vitro maturation (IVM) and further embryo development. Cumulus-oocytes complexes (COCs) were subjected (experimental group) or not (control group) to irradiation with LLLI in a 633-nm wavelength and 1 J/cm 2 fluency. The COCs were evaluated after 30 min, 8, 16, and 24 h of IVM. Cumulus cells were evaluated for cell cycle status, mitochondrial activity, and viability (flow cytometry). Oocytes were assessed for meiotic progression status (nuclear staining), cell cycle genes content [real-time polymerase chain reaction (PCR)], and signal transduction status (western blot). The COCs were also in vitro fertilized, and the cleavage and blastocyst rates were assessed. Comparisons among groups were statistically performed with 5% significance level. For cumulus cells, a significant increase in mitochondrial membrane potential and the number of cells progressing through the cycle could be observed. Significant increases on cyclin B and cyclin-dependent kinase (CDK4) levels were also observed. Concerning the oocytes, a significantly higher amount of total mitogen-activated protein kinase was found after 8 h of irradiation, followed by a decrease in all cell cycle genes transcripts, exception made for the CDK4. However, no differences were observed in meiotic progression or embryo production. In conclusion, LLLI is an efficient tool to modulate the granulosa cells and oocyte metabolism.
Collagen makes up one third of the total protein in humans, being formed by the connection of three polypeptide chains
arranged in a triple helix. This protein has fundamental importance in the formation of extracellular matrix of connective
tissue. This study aimed to analyze the structural changes of collagen, which are resulting from inflammatory processes
in oral mucosa, and to make the comparative analysis between the histopathology and the Raman spectra. The samples of
tissues with inflammatory fibrous hyperplasia (IFH) and normal mucosa (NM) were evaluated by Raman Spectroscopy,
hematoxylin-eosin and Massons trichrome stain. The histological analysis in both stains showed differences in collagen
fibers, which was presented as thin fibers and arranged in parallel direction in NM and as collagen fibers are thick,
mature and not organized, showing that these types of stain show morphological changes of collagen in IFH. The Raman
Spectroscopy discriminate the groups of NM and IFH based on vibrational modes of proline, hydroxiproline and CH3,
CH2. The histological stains only shows information from morphological data, and can be complemented by Raman
spectra. This technique could demonstrate that inflammatory process caused some changes in collagen structure which is
related to aminoacids such as proline and hidroxyproline.
This paper presents optimization of active, passive, and hybrid damping treatments in sandwich plates. A new
mixed layerwise finite element model has been developed for the analysis of sandwich laminated plates with a
viscoelastic core, laminated anisotropic face layers and piezoelectric sensor and actuator layers. Proportional
displacement and velocity feedback control laws are implemented to account for co-located active control. Optimization
of passive damping is conducted by maximizing modal loss factors, using as design variables the
viscoelastic core thickness and the constraining elastic layers ply thicknesses and orientation angles. Optimization
of the location of co-located sensor-actuator pairs is also conducted in order to maximize modal loss factors.
The optimization problem is solved using gradient-based techniques for passive damping and an implementation
of a Genetic Algorithm for the optimal location of sensor-actuator pairs.
This paper addresses bending of multilayered cylindrical shells with piezoelectric properties using a semi-analytical axisymmetric shell finite element model with piezoelectric layers using the 3D linear elastic theory. In the present model, the equations of motion are derived by expanding the displacement field using the Fourier series in the circumferential direction. Thus, the 3D elasticity equations of motion are reduced to 2D equations involving circumferential harmonics. In the finite element formulation the dependent variables, electric potential and loading are expanded in truncated Fourier series. Special emphasis is given to the coupling between symmetric and anti-symmetric terms for laminated materials with piezoelectric rings. Numerical results obtained with the present model are found to be in good agreement with other finite element solutions.
This paper deals with the development of a general finite element formulation of the layerwise theory that was proposed and advanced by the first author for laminated plate structures with piezoelectric materials (layers or patches). The formulation includes full electromechanical coupling. Several approximations are used for the primary variables of the theory in the thickness direction and different interpolation schemes are considered in the surface directions. A very good agreement is obtained for the models using cubic approximation in the thickness direction. The advantages of these models on the prediction of layer stresses are fully illustrated.
SiO2-TiO2:Er3+-Yb3+ waveguides were prepared by rf-sputtering technique. The active films were deposited on silica-on-silicon and v-SiO2 substrates. The parameters of preparation were chosen in order to optimize the waveguides for operation in the NIR region with particular attention to the minimization of losses. The thickness of the waveguides and the refractive index at 632.8 and 543.5 nm were measured by an m-line apparatus. The losses, for the TE0 mode, were evaluated at 632.8 and 1300 nm. Roughness measurements were carried out by means of a stylus profilometer. The structural properties were investigated with several techniques such as Energy Dispersive Spectroscopy and Raman Spectroscopy. All waveguides were single-mode at 1550 nm. An attenuation coefficient equal or lower than 0.2 dB/cm was measured both at 632.8 nm and 1300 nm. The emission 4I13/2 →4I15/2 of Er3+ ion transition with a 40 nm bandwidth was observed upon excitation in the TE0 mode at 981 and 514.5 nm. Back energy transfer from Er3+ to Yb3+ was demonstrated by measurement of Yb3+ emission upon Er3+ excitation at 514.5 nm. Photoluminescence excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er3+ ions by co-doping with Yb3+ ions. Channel waveguides in rib configuration were obtained by etching the active film by a wet etching process. Scanning Electron Microscopy was used to analyze the morphology of the waveguides.
In the present work, a finite element model based on the layerwise theory of Reddy is developed for laminated plates including piezoelectric layers or patches. Several interpolation schemes are considered and the results achieved are discussed by comparison with 3D elasticity analytical solutions.
In this work, refined finite element models based on higher order displacement fields have been developed to study the mechanical and electrical behavior of laminated composite plate structures with embedded and/or surface bonded piezoelectric actuators and sensors. Sensitivity analysis and optimization techniques are also applied in order to maximize the piezoelectric actuator efficiency, improve the structural performance and/or minimize the weight of the structure. To show the performance of the proposed models several illustrative and simple examples are presented.
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