Volatile components in the essential oil of wild oregano (Coleus amboinicus Lour.)

The essential oil of Coleus amboinicus Lour. plants, growing in Cuba, was investigated by means of LSC, GLC and GC-MS. A total of 20 components were identified, including 13 terpene hydrocarbons and 7 oxygenated compounds. The oil contained about 64% carvacrol.     

Can Human Oral Mucosa Stem Cells Differentiate to Corneal Epithelia?

Human oral mucosa stem cells (hOMSCs) arise from the neural crest, they can self-renew, proliferate, and differentiate to several cell lines and could represent a good source for application in tissue engineering. Because of their anatomical location, hOMSCs are easy to isolate, have multilineage differentiation capacity and express embryonic stem cells markers such as—Sox2, Oct3/4 and Nanog. We have used SHEM (supplemented hormonal epithelial medium) media and cultured hOMSCs over human amniotic membrane and determined the cell’s capacity to differentiate to an epithelial-like phenotype and to express corneal specific epithelial markers—CK3, CK12, CK19, Pan-cadherin and E-cadherin. Our results showed that hOMSCs possess the capacity to attach to the amniotic membrane and express CK3, CK19, Pan-Cadherin and E-Cadherin without induction with SHEM media and expressed CK12 or changed the expression pattern of E-Cadherin to a punctual-like feature when treated with SHEM media. The results observed in this study show that hOMSCs possess the potential to differentiate toward epithelial cells. In conclusion, our results revealed that hOMSCs readily express markers for corneal determination and could provide the ophthalmology field with a therapeutic alternative for tissue engineering to achieve corneal replacement when compared with other techniques. Nevertheless, further studies are needed to develop a predictable therapeutic alternative for cornea replacement.     

Fatty acid profiles in meat from Caiman yacare (Caiman crocodilus yacare) raised in the wild or in captivity

Chemical composition and fatty acid profiles were determined in Caiman yacare meat originating from the neck and tail cuts of animals raised in the wild (n = 6) or in captivity (n = 6), slaughtered at a live weight of approximately 6 kg. All experimental methods were approved by the appropriate environmental protection agencies. Most chemical components were affected by the origin-cut interaction, with the tail cut of wild animals having the highest amount of intramuscular fat (19.2% of DM) and the lowest of moisture (71.8%) and protein (77.0% of DM). Yacare meat had low amounts of SFA (35.1%), which were similar (P > 0.05) in the cuts and origins studied. The total amount of PUFA was higher (P < 0.05) in wild (31.0%) than in captive animals (23.6%), and n − 3 fatty acids had means of about 5% and 2% for the same groups, respectively (P < 0.05). In general, the FA profile of intramuscular fat in yacare meat had a desirable PUFA/SFA ratio above 0.4.     

Polaronic effects on the collective excitation energies in a quantum wire

In this work we report a investigation of the plasmon–longitudinal-optical (LO) phonon interaction effects on the intersubband and intrasubband collective excitation energies in a GaAs–Al_νGa_1?νAs rectangular quantum well wire. We observe a resonant split of the collective excitation energy into two branches, one with energy lower and other with energy higher than the LO-optical phonon energy ?ω_LO. Our calculations are performed using a self-consistent field approximation, which includes the local-field correction within the Singwi, Tosi, Land, and Sjolander (STLS) theory at zero temperature and assuming a three-subband model, where only the first subband is occupied by electrons. The potential confining effects on the collective energies were also considered.     

Comparison of matrix solid-phase dispersion and liquid-liquid extraction for the chromatographic determination of fenthion and its metabolites in olives and olive oils

Matrix solid-phase dispersion (MSPD) methodology has been developed to extract fenthion and its metabolites from olives and olive oils, and the technique compared with conventional liquid-liquid extraction (LLE). The method was applied to olives and olive oil samples obtained from olive groves treated with fenthion. Pesticide residues were analysed by gas chromatography (GC) using a nitrogen-phosphorus detector. Both extraction methods gave a linear response over the concentration range assayed (0.03-1 mg kg^-1 for MSPD and 0.1-1 mg kg^-1 for LLE). Recoveries and RSD (n = 6) values in olives were 85-112% and 2-6% for MSPD, and 68-108% and 4-16% for LLE, respectively. In the case of olive oil, recoveries and RSD (n = 6) values were 67-98% and 5-11% for MSPD, and 63-115% and 6-14% for LLE, respectively. When compared to LLE, the newly developed MSPD method was twice as sensitive and required 10 times less sample weight.     

Relative quantification of <Emphasis Type="Italic">Vitis vinifera</Emphasis> L. varieties in musts by microsatellite DNA analysis

Varietal wines are defined as made primarily from a single variety of grape, which is identified on the label. However the inclusion of other varieties in their production is permitted under defined percentages. The fact that different grape varieties/varietal wines present far different economical values can attract fraudulent practices. Thus the development of methods, which allow the quantification of those varieties, is of crucial importance. The first approach to the method for the relative quantification of must containing two varieties based on microsatellite DNA analysis is presented. Quantification was achieved by densitometry measurements of the amplification products of the pooled varieties, obtained with loci VVMD6 and VVMD7, after their separation and staining on polyacrilamide gels. We have found that a good correlation between the proportion of each variety in must and the signal intensity of the alleles are dependent on the variety (varietal effect) and the microsatellite locus used. The relative quantification of musts can be accomplished by the presented method depending on the presence of overlapping alleles, and the composition of the varieties and their relative amounts.     

Hydrometallurgical separation of aluminium,cobalt, copper and lithium from spent Li-ion batteries

A hydrometallurgical route based on leaching-crystallization steps for the separation of metals Al, Co, Cu and Li from spent Li-ion batteries was evaluated in this paper. Once dismantled for the removal of both plastic and steel cases, the anode (containing mainly Cu) of such batteries was manually separated from the cathode (which contains Al, Co and Li) for the recovery of Cu. The metal content of both anode and cathode was assessed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and atomic absorption analytical methods. The cathode was firstly leached with NaOH for the selective removal of Al, followed by leaching with H₂SO₄ + H₂O₂ for the dissolution of the remaining Co and Li. The operating variables concentration of NaOH and concentration of H₂O₂ were found significant for the metal dissolution conditions investigated at basic and acid leaching operations, respectively. On the other hand, the variables temperature and concentration of H₂SO₄ showed minor effects at acid leaching step. Reaction schemes were proposed to describe basic and acid leaching operations. The recovery of Co from the acid liquor was carried out by crystallization. This hydrometallurgical route was found to be simple and adequate to separate metals for recycling purposes.     

How efficient are African electricity companies? Evidence from the Southern African countries

This paper is a first attempt at documenting efficiency levels in Africa's electricity firms, their evolution and the sources of this evolution. The analysis is based on a sample of 12 operators providing services in the 12 country members of the Southern Africa Power Pool. We focus on the changes in total factor productivity (TFP) of the largest operators in each country between 1998 and 2005. We then rely on a data envelopment analysis (DEA) decomposition to identify the sources of the changes in TFP. The results suggest fairly comparable levels of efficiency in the region and performance levels and evolution quite independent of the degree of vertical integration, the presence of a private actor or the main sources of energy supply. The analysis suggest that although the companies have not made significant improvements during the period of analysis in using their capital and human assets, they have done much better in adopting better technologies and better commercial practices. No clear correlation could be associated with the adoption of reforms during the last decade and data limitations impede a more refined assessment of the impact of reforms on efficiency at this stage.