Acceptability and nutritional quality of a beverage based on orange juice and whey powder, preserved by heat or high-intensity pulsed electric fields (HIPEF)

Orange juice may be a nutrient vehicle that helps to improve diet quality. The addition of whey allows the incorporation of high quality proteins. However, a good acceptability is necessary. The aims of the present study were: a) to assess the acceptability of a beverage prepared with orange juice (J) and whey powder (WP) at 7 g/100 g (J+WP7) or at 13 g/100 g (J+WP13); b) to measure available lysine content and ascorbic acid retention of the more accepted formulation, comparing the effect of HIPEF treatment (29 kV/cm, t(acum): 59 micros) with a conventional heat treatment at 75 degrees C, for 15 minutes (HT). The beverages were subjected to sensory evaluation (Friedman test). Available lysine was assessed by the Carpenter method, modified by Booth, and vitamin C by HPLC; minerals Na and K, by flame photometry; Ca, Mg and Zn by atomic absorption spectrometry. There were no significant differences between the acceptance of J and J+WP7. J+WP13 was significantly less accepted (p < 0.01), so it was discarded. Available lysine (mg/g protein) in untreated J+WP7 was 60.2 +/- 0.15; after treatments: 50.0 +/- 2.8 (HT) and 51.0 +/- 3.4 (HIPEF). The HIPEF treated J and (J+WP7) retained 100% and 98% of their vitamin C initial content and the HT treated, 91% and 88%, respectively. The amount of whey powder added to the orange juice conditioned the acceptability. The juice containing 7% of whey powder was well accepted, and after treatment by HIPEF, it retained a good nutritional quality, regarding available lysine, vitamin C retention and provision of mineral nutrients.     

Tribological performance of hybrid organo-silicate coatings

Hybrid organo-silicate coatings (hybrid coatings) present many advantages and find use in many applications. However, their tribological performance has not been widely investigated due to the non-uniformity of the synthesized hybrid materials. In this work, nanoscratch tests have been employed for the investigation of wear mechanisms and organic–inorganic coatings adhesion. The tribological performance was investigated under low applied normal forces, in order to estimate the coefficient of friction (μ) values, the coatings resistance and the humidity effect when the synthesized coatings were submerged on a cell culture medium. Also, the performed plastic deformation was correlated with the experimental data and the surface images taken with a scanning probe microscope after the scratch tests. Furthermore, the experimental data were fitted and the relative coefficient of friction and cohesive force of each synthesized coating were calculated, since organic and hybrid materials do not conform with the classic tribology laws and are greatly affected by the adhesion forces observed between tip and sample's surface.     

Carcinogenesis of Pancreatic Adenocarcinoma: Precursor Lesions

Pancreatic adenocarcinoma displays a variety of molecular changes that evolve exponentially with time and lead cancer cells not only to survive, but also to invade the surrounding tissues and metastasise to distant sites. These changes include: genetic alterations in oncogenes and cancer suppressor genes; changes in the cell cycle and pathways leading to apoptosis; and also changes in epithelial to mesenchymal transition. The most common alterations involve the epidermal growth factor receptor (EGFR) gene, the HER2 gene, and the K-ras gene. In particular, the loss of function of tumor-suppressor genes has been documented in this tumor, especially in CDKN2a, p53, DPC4 and BRCA2 genes. However, other molecular events involved in pancreatic adenocarcinoma pathogenesis contribute to its development and maintenance, specifically epigenetic events. In fact, key tumor suppressors that are well established to play a role in pancreatic adenocarcinoma may be altered through hypermethylation, and oncogenes can be upregulated secondary to permissive histone modifications. Indeed, factors involved in tumor invasiveness can be aberrantly expressed through dysregulated microRNAs. This review summarizes current knowledge of pancreatic carcinogenesis from its initiation within a normal cell until the time that it has disseminated to distant organs. In this scenario, highlighting these molecular alterations could provide new clinical tools for early diagnosis and new effective therapies for this malignancy.     

Influence of Geometrical Factors on Cavity Pressure During the Injection Molding Process

The influence of the geometrical factors of plastic parts (shape factor, thickness, length/thickness ratio, and section changes) on the behavior of the cavity pressure during the injection process was studied. The instrumentation of injection molds was proposed, placing pressure transducers in the more critical zones of the parts. The evaluation of the molds was made using solid modelator and simulator software of the injection process with different polymers. The geometric factors determine the processing conditions to be used, the behavior of the cavity pressure during filling and postfilling phases, the cooling, and the dimensional stability of the part.     

Poly(N-vinylpyrrolidone) as metal ion liquid-liquid extractant

SUMMARY Poly(N-vinylpyrrolidone) (PVP) was investigated as a novel extracting agent. The metal ion extraction properties for Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II), Hg(II), Cr(III) and Fe(III) were investigated using the liquid-liquid solvent extraction technique (bath method). The metal ion interactions with the polymer were determined as a function of the pH as well as the kinetic characteristic and stripping. For copper ions pH 4 was the optimum extracting pH value, and the 2M hydrochloride acid was better than nitric acid as a stripping agent. Received: 7 September 2000/Revised version: 14 September 2000/Accepted: 14 September 2000