Air entrainment on a moving continuous web

The air boundary layer on a moving continuous web was experimentally investigated in a laboratory coating equipment. The boundary layer thickness was obtained by smoke visualization and measured by image analysis in the range 2.4×10⁴<Re<3×10⁵. According to the web speed, three laminar flow mechanisms were observed, for which the air boundary layer thickness was found to vary from 0.74 to . A survey of the published boundary layer solutions for a moving flat surface was also carried out and their applicability to the present boundary layer problem was studied. It was shown that the Blasius solution is the most suitable to represent the air flow in the case of a moving web.     

Stability of sorbic and ascorbic acids in packed green table olives during long-term storage as affected by different packing conditions,and its influence on quality parameters

The effect of different packing conditions on sorbate stability was studied in Spanish-type green table olives stored for up to one year. The factors studied were preservation treatment (pasteurisation vs. non-pasteurisation), storage temperature (room temperature vs refrigeration), packaging material (glass bottle vs. plastic pouch), storage time, and the presence or not of an antioxidant additive (ascorbic acid). Sorbic acid was stable in pasteurised samples as well as in the refrigerated unpasteurised samples, both in the absence and in the presence of ascorbic acid. In unpasteurised samples stored at room temperature, sorbic acid gradually disappeared, with a concomitant increase in the concentration of trans-4-hexenoic acid, which could be attributable to the action of lactic acid bacteria. Ascorbic acid was always less stable than sorbate. Sorbate addition negatively affected the colour parameters of both fruit and brine. An appreciable off-flavour was detected in the samples in which sorbate had been degraded.     

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.     

Assessment of the Use of NaClO as an Alternative to H2O2 in the Oxidant-Titanium Ore-Simulated Solar Light System for Thiabendazole Degradation

Topics in Catalysis - The use of the magnetic fraction (MF) of a low-grade titanium ore (TO) and two oxidants (H2O2 and NaClO), testing each one separately, were compared in photo-Fenton like...     

A trigonometrically-fitted method with two frequencies,one for the solution and another one for the derivative

In trigonometrically-fitted methods the determination of the parameter (usually known as the frequency) is a critical issue, as was shown in the article by H. Ramos and J. Vigo-Aguiar [Applied Mathematics Letters, 23 (2010) 1378–1381]. If the frequency estimation relies on the vanishing of the principal term of the local truncation error, then the first derivative is present in the formula for approximating the parameter. This requires the use of a procedure for approximating the first derivative. For this purpose we use another trigonometrically-fitted formula with a second parameter (different from the frequency of the principal method and also different from the frequency of the true solution). We describe how to approximate both parameters on each step and present different experiments concerning these questions. The numerical results indicate the good performance of the strategy.     

Degradation of ascorbic acid and potassium sorbate by different Lactobacillus species isolated from packed green olives

The aim of this research was to ascertain the lactic acid bacteria responsible for the degradation of ascorbic acid and/or potassium sorbate, isolated from packed green olives where these additives had diminished. A total of 14 isolates were recovered from samples of different green olive containers. According to partial sequencing of the 16S rRNA coding gene, Lactobacillus parafarraginis, Lactobacillus rapi, Lactobacillus pentosus, Lactobacillus paracollinoides, and Pediococcus ethanolidurans were identified. With the exception of L. pentosus and L. paracollinoides, the other species had not been mentioned in table olives before this study. Only three of the 14 isolates metabolized ascorbic acid in MRS broth, and the products from ascorbic acid in modified MRS broth without carbon sources were acetic and lactic acids. Except for the two L. rapi and the two P. ethanolidurans strains, the remaining 10 isolates depleted potassium sorbate added into MRS broth to some extent. The product generated by three of these strains was confirmed to be trans-4-hexenoic acid. The degradation of ascorbate or sorbate by lactic acid bacteria should be taken into account when these additives are used in food products where this group of bacteria may be present.     

Analysis of the biomineralization process on SWNT-COOH and F-SWNT films

In vitro biomineralization process was investigated on functionalized single wall nanotube (SWNT) films. The films were prepared by solvent casting method by using carboxylated and fluorinated nanotubes. SWNT films were characterized by means of electron microscopy, contact angle measurements and optical absorption. The in vitro assays were performed on cultured human alveolar bone-derived cells (HABDC) to determine the capabilities of carboxylated single-walled nanotubes (SWNTs-COOH) and fluorinated single-walled nanotubes (F-SWNTs) to promote the deposit of mineral-like tissue. The results showed that the cellular response of HABDC in secreting a mineralized extracellular matrix and their consequent mineralization is dependent on the degree of functionalization of the SWNTs. Differences were found related to the kind of sidewall functionalization. Both structures promoted hydroxyapatite formation, however, calcium uptake on SWNTs-COOH increased and it was related to crystal density. From our results, it is possible to infer that CNT functionalization opens a path to future developments in new bone graft materials and techniques.     

Uncertainty evaluation of the 1 GHz GPR antenna for the estimation of concrete asphalt thickness

The uncertainty evaluation in the measurement of pavement thickness using ground penetrating radar is depicted in this work for operating frequencies of 1 GHz. Three areas of pavement with a number of different layers and thicknesses, the influence of two different human operators and the calibration/non-calibration of the radar signal were taken into account to evaluate the uncertainty contribution.     

Chemical and colour changes related to the use of sorbates and ascorbic acid in pickled cucumbers and caperberries during long‐term storage

The evolution of two additives, potassium sorbate and ascorbic acid, during long‐term storage of pickled vegetables, as well as the impact of these additives on product colour, was investigated. For this investigation, cucumbers and caperberries packed in both glass bottles and plastic pouches were used. In general, the added sorbate level remained unchanged during long‐term storage irrespective of the packaging material. However, the ascorbic acid gradually disappeared at a significantly higher rate in plastic than in glass containers, and its level was higher in caperberries than in cucumbers. In the latter, the presence of sorbate caused a higher degradation rate of ascorbic acid compared to the absence of sorbate. Ascorbic acid had a protective effect against surface colour degradation in cucumbers packed in plastic pouches, whereas sorbate enhanced such degradation. However, in both pickled vegetables, ascorbic acid degradation had a significant impact on brine browning, particularly in plastic pouches.