Mass spectrometry fingerprinting of media used for in vitro production of bovine embryos

Using the bovine species as a biological model, direct infusion chip‐based nano‐electrospray ionization mass spectrometry (nano‐ESI‐MS) fingerprinting in the positive ion mode is used to obtain fast chemical profiles of media used for in vitro production of bovine embryos. Nano‐ESI‐MS fingerprinting is useful for characterization and routine quality control requiring no sample pre‐separation, being able to differentiate four different media (IVM, IVF, SOF and HSOF) via principal component analysis (PCA). For media stored at +4°C for up to 45 days, no significant (p > 0.05) variation was observed in cleavage and blastocyst rate development, as well as in the nano‐ESI‐MS chemical profiles. For media exposed to a heat shock (60°C for 3 h), no significant decrease (p > 0.05) in embryo development rates was observed, but nano‐ESI‐MS profiles were quite distant from fresh control media in the PCA. For frozen media (?70°C for 2 months), again no significant variation (p > 0.05) in embryo development was noticed, but nano‐ESI‐MS profiles from all media were significantly affected. These results indicate that nano‐ESI(+)‐MS fingerprinting was able to characterize different media based on their specific chemical profile. The technique seems therefore applicable as a routine quality control assay, detecting, for example, compositional changes after temperature variations that may affect post‐transfer embryo viability. Copyright © 2009 John Wiley & Sons, Ltd.     

The role of defect states in the creation of photoluminescence in SrTiO<Subscript>3</Subscript>

We discuss the nature of visible photoluminescence at room temperature in amorphous strontium titanate in the light of the results of a recent experimental and quantum mechanical theoretical study. Our calculation of the electronic structure involves the use of first-principles molecular calculations to simulate the variation of the electronic structure in the strontium titanate crystalline phase, which is known to have a direct band gap, and we also make an in-depth examination of amorphous strontium titanate. The results of our simulations of amorphous strontium titanate indicate that the formation of five-fold coordination in the amorphous system may introduce delocalized electronic levels in the highest occupied molecular orbital and the lowest unoccupied molecular orbital. These delocalized electronic levels are ascribed to the formation of a tail in the absorbance-spectrum curve. Optical absorption measurements experimentally showed the presence of a tail. The results are interpreted by the nature of these exponential optical edges and tails associated with defects promoted by the disordered structure of the amorphous material. We associate them with localized states in the band gap. Received: 15 January 2002 / Accepted: 7 August 2002 / Published online: 4 December 2002 RID="*" ID="*"Corresponding author. Fax: +55-16/2615-215, E-mail: derl@power.ufscar.br     

Screening analysis to detect adulteration in diesel/biodiesel blends using near infrared spectrometry and multivariate classification

This paper proposes an analytical method to detect adulteration of diesel/biodiesel blends based on near infrared (NIR) spectrometry and supervised pattern recognition methods. For this purpose, partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) coupled with the successive projections algorithm (SPA) have been employed to build screening models using three different optical paths and the following spectra ranges: 1.0 mm (8814-3799 cm⁻¹), 10 mm (11,329-5944 cm⁻¹ and 5531-4490 cm⁻¹) and 20 mm (11,688-5952 cm⁻¹ and 5381-4679 cm⁻¹). The method is validated in a case study involving the classification of 140 diesel/biodiesel blend samples, which were divided into four different classes, namely: diesel free of biodiesel and raw vegetal oil (D), blends containing diesel, biodiesel and raw oils (OBD), blends of diesel and raw oils (OD), and blends containing a fraction of 5% (v/v) of biodiesel in diesel (B5). LDA-SPA models were found to be the best method to classify the spectral data obtained with optical paths of 1.0 and 20 mm. Otherwise, PLS-DA shows the best results for classification of 10 mm cell data, which achieved a correct prediction rate of 100% in the test set.     

Augmentation of the Porcine Vocal Fold Using Autologous Composite Cervical Fascia and Fat Graft. Comparison Between the Transmuscular and Submuscular Approaches

Objectives

To assess the integration of an autologous composite fascia and fat graft implanted into the lamina propria of a porcine vocal fold using two different approaches.

Study Design

An experimental prospective study on the porcine larynx was conducted at a tertiary research institution.

Methods

An external cervical approach was used to expose the thyroid cartilage of 24 healthy minipigs under general anesthesia. The composite fascia/fat graft was implanted through two distinct approaches, transmuscular and submuscular. Animals were sacrificed at 7, 30, 90, and 180 days for macroscopic and histological study of the larynx. Graft integration and local inflammatory response were studied.

Results

The survival rate of the experimental model was 100% and all animals had local inflammatory response to the surgical procedure. Only 41.7% of the grafts placed inside the thyroarytenoid (TA) muscle fibers were identified postmortem, whereas 83.3% of the submuscular grafts remained intact.

Conclusions

Graft incorporation was better and there was less inflammation when the architecture of the TA muscle fibers was preserved. Graft extrusion was observed in the most of the cases where it was placed inside the muscle.     

Rosemary (Rosmarinus officinalis L.) extract

The restriction to the use of synthetic antioxidants has fostered the research on natural antioxidants, taking into account that the prolonged usage of these substances can harm seriously the human being provoking degenerative diseases. In the present study, the antioxidant effect of the ethanolic rosemary (Rosmarinus officinalis L.) extract on the oxidative stability of edible vegetable oils was investigated by means of the pressurized differential scanning calorimetry (PDSC) and oven test techniques. The rosemary extract, at the concentration of 2,000 mg kg^?1, as well as the synthetic antioxidant tert-butylhydroquinone (TBHQ) at the concentrations of 100 and 200 mg kg^?1 were added to samples of sunflower oil, corn oil, and soybean oil. The fatty acid profiles of the vegetable oils were determined by gas chromatography–mass spectrometry confirming the elevated contents of unsaturated fatty acids. The thermogravimetric analysis showed that the rosemary extract is stable at the frying temperature of the oils. The results of the oxidative stability demonstrated that the extract of Rosmarinus officinalis displayed a more effective protective action in the PDSC technique, when compared with the synthetic antioxidant TBHQ, indicating that it is a promising source of natural antioxidants for edible vegetable oils.     

Simultaneous spectrophotometric determination of pyrantel pamoate and febantel in pharmaceutical preparations using partial least-squares regression

The multivariate spectroscopic determination of the combination of pyrantel pamoate (PP) and febantel (FB) in pharmaceutical preparations was carried out by partial least-squares regression. The UV absorbance spectra of standard mixtures of PP and FB were measured at concentrations ranging from 5.76–11.52 and 6–12 μg/mL, respectively, in a diluent solution of methanol and acetonitrile. The best model was selected with variable selection (280–320, 380–400 nm), 2 latent variables and mean centered. External validation was performed using 13 different mixtures, which provided prediction errors lower than 1%. The method was validated in accordance with international and Brazilian guidelines. This method was successfully employed to quantify the drug content in two different pharmaceutical formulations (solid — capsules, liquid — oral suspensions) with good prediction capacity. Furthermore, its advantages include the use of simple and accessible reagents and equipment, and a low operating cost.     

Bilayer graphene on h-BN substrate: investigating the breakdown voltage and tuning the bandgap by electric field

By performing density functional theory calculations we show that it is possible to make the electronic bandgap in bilayer graphene supported on hexagonal boron nitride (h-BN) substrates tunable. We also show that, under applied electric fields, it is possible to insert states from h-BN into the bandgap, which generate a conduction channel through the substrate making the system metallic. In addition, we verify that the breakdown voltage strongly depends on the number of h-BN layers. We also show that both the breakdown voltage and the bandgap tuning are independent of the h-BN stacking order.     

Numerical modelling of the hydrodynamic field coupled to the transport of chemical species through the finite-element method

We describe the main features of a numerical simulator currently under development for studying water physico-chemical properties during the flooding of hydroelectric plants reservoirs. The work is sponsored by the brazilian Electric Energy National Agency ANEEL and conducted in a joint work of brazilian universities rearchers, with Furnas Centrais Elétricas S. A., the leading brazilian power utility company. An overview of the simulator requirements and of the involved partners is given. The software modules and engineering solutions are briefly discussed, including the finite element based transport module. Some results, future steps and partnerships are presented and discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Characterization of a crystal grown from Ocimum Basilicum leaves and branches

Leaves and branches of Ocimum Basilicum were dried, reduced to coarse powder and extracted in aqueous metanol and aqueous hexane. This paper discusses the X‐ray diffraction and FT‐Raman spectra measured at room temperature. The data obtained have been used to propose a general assignment of the vibrational fundamentals on the base of frequencies assigned in other related single crystals. From the results we can conclude that the crystal has a high symmetry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)