Development of yoghurt from ovine milk with enhanced texture and flavour properties

Six commercial starter cultures, all blends of Streptococcus thermophilus sp. and Lactobacillus bulgaricus sp., were compared for enhanced texture and flavour in yoghurt prepared from ovine milk. The fermentation patterns differed between starters, with YF‐L903 (E) showing the fastest fermentation but slower post‐acidification. YC‐X11 (A) produced the slowest acidification, while YC‐380 (B) resulted in the fastest post‐acidification. Textural and colour properties were affected significantly by the culture used. YF‐L903 (E) enhanced the firmness and luminosity of the yoghurt over storage, increasing mouthfeel and creaminess, as compared to yoghurts prepared with the other starter cultures starters studied.     

FDTD modeling of wave propagation in dispersive media by using theMobius transformation technique

This paper introduces a technique for finite-difference time-domain modeling of wave propagation in general Mth-order dispersive media. Ohm's law in the Laplace domain with an Mth-order rational model for the complex conductivity is considered as a constitutive relation. In order to discretize this model, the complex conductivity is mapped onto the Z-transform domain by means of the Mobius transformation. This leads finally to a set of difference equations that is consistent with Yee's scheme. The resulting formulation is explicit, it has a second-order accuracy, and the need for additional storage variables is minimal. The numerical stability problem is discussed and the numerical dispersion equation for Mth-order media is given     

Hydrothermal processing of rice husks: effects of severity on product distribution

BACKGROUND: Treatment in aqueous media (hydrothermal or autohydrolysis reactions) is an environmentally friendly technology for fractionating lignocellulosic materials. Rice husks were subjected to hydrothermal processing under a variety of operational conditions to cause the selective breakdown of xylan chains, in order to assess the effects of reaction severity on the distribution of reaction products. RESULTS: The effects of severity (measured by the severity factor, R₀) on the concentrations of the major autohydrolysis products (monosaccharides, xylo‐ and glucooligosaccharides, xylooligosaccharide substituents, acetic acid, acid‐soluble lignin and elemental nitrogen) were assessed. The interrelationship between the severity of treatment and molecular weight distribution was established by high‐performance size‐exclusion chromatography. Selected samples were subjected to refining treatments as ethyl acetate extraction and ion exchange for refining purposes, and the concentrates were assayed by high‐performance anion‐exchange chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. CONCLUSIONS The protein equivalent of the products present in liquors accounted for 43 to 51% of the protein present in the raw rice husks. The concentrations of glucose (derived from starchy material) and arabinose (split from the xylan backbone) were fairly constant with severity. Even in treatments at low severity, high molecular weight compounds derived from xylan accounted for a limited part of the stoichiometric amount. Operating under harsh conditions, about 50% of the total xylan‐derived compounds corresponded to fractions with a degree of polymerization (DP) < 9. After refining, saccharides accounted for more than 90% of the non‐volatile components of the sample. The refined products showed a series of xylose oligomers up to about DP 13, and a series of acetylated xylose oligomers up to about DP 15. Copyright © 2008 Society of Chemical Industry     

Properties of Calcined Clay Waste and its Influence on Blended Cement Behavior

This paper describes research on clay wastes (CWs) produced in the paper manufacture process. Once activated under controlled thermal conditions, CW is transformed into calcined clay products providing added value as supplementary cementing materials. The obtention of a pozzolanic material (metakaolin (MK)) from valorized CW constitutes an alternative source of pozzolans for the elaboration of blended Portland cements, as well as a priority research line from the environmental point of view. This research work presents the properties of calcined CW (chemical, mineralogical, and pozzolanic) and its influence on Portland cements containing 10% calcined clay product. The results obtained with different characterization techniques (XRF, DTA, XRD, SEM-EDX) showed that the thermally activated CW exhibits acceptable properties to be used as supplementary cementing materials in the manufacture of commercial Portland cements. The derived MK can react with calcium hydroxide, from cement hydration, producing hydrated phases with hydraulic properties (calcium silicate hydrate gels, tobermorite, C₄AH₁₃, zeolite). These novel blended cements comply with the chemical, physical, and mechanical specifications established in the existing standards.     

Analyzing the stability of the FDTD technique by combining the vonNeumann method with the Routh-Hurwitz criterion

This paper addresses the problem of stability analysis of finite-difference time-domain (FDTD) approximations for Maxwell's equations. The combination of the von Neumann method with the Routh-Hurwitz criterion is proposed as an algebraic procedure for obtaining analytical closed-form stability expressions. This technique is applied to the problem of determining the stability conditions of an extension of the FDTD method to incorporate dispersive media previously reported in the literature. Both Debye and Lorentz dispersive media are considered. It is shown that, for the former case, the stability limit of the conventional FDTD method is preserved. However, for the latter case, a more restrictive stability limit is obtained. To overcome this drawback, a new scheme is presented, which allows the stability limit of the conventional FDTD method to be maintained     

Renal transplant in patient older than 65 years of age

OBJECTIVE: To analyze the outcome of renal transplantation in patients more than 65 years old. METHODS: From 1991 to 1997, 83 renal transplants were performed in patients aged over 60 years at our institution; 20 of these patients were more than 65 years old. The control group comprised graft recipients under than age from the 477 cases that had undergone transplantation during the period 1980-1996. Graft donor selection was done according to standard practice. The immunosuppression protocol changed over time; 5 patients received triple therapy and another 15 patients received quadruple sequential immunosuppression therapy. RESULTS: The mean age of the recipients was 66.8 years (range 65-72); 9 patients required dialysis after renal transplantation. Patients aged over 65 years had a 94% survival at 6 months, 88% at 12 months, and 88% at 48 months, whereas the survival rates for the control group were 96%, 95% and 87% for the respective time periods. Graft survival was 95% at one month, 90% at 3 months and 74% at 48 months versus 93%, 87% and 78% for the control group. CONCLUSION: Patients more than 65 years old with chronic renal failure and who are on dialysis can benefit from renal transplantation.     

Surgery of the laryngeal framework: type I thyroplasty]

Pentosidine is an advanced glycation end product (AGE) formed by combined processes of glycation and oxidation (glycoxidation) between carbohydrate-derived carbonyl group and protein amino group. Recent studies demonstrated the increased pentosidine levels not only in diabetic patients with hyperglycemia but also in normoglycemic uremic patients due to increased oxidative stress. Rheumatoid arthritis (RA) is a state of increased oxidative stress associated with chronic inflammation. This suggested an enhanced glycoxidation reaction and increased AGE levels in RA patients. In the present study, we therefore determined, by high performance liquid chromatographic (HPLC) assay, the concentrations of pentosidine in plasma and synovial fluid from 22 patients with rheumatoid arthritis (RA) and compared their levels with those in 17 patients with osteoarthritis (OA), 26 diabetic patients, and 25 normal subjects. The levels of inflammatory markers and markers of tissue destruction, metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), were also measured in the same samples. Pentosidine levels in plasma and synovial fluid from RA patients were significantly higher than those in OA patients, diabetic patients, and normal subjects. There was a significant correlation between the pentosidine levels in plasma and those in synovial fluid. Among markers of inflammation and matrix destruction, pentosidine levels in plasma from RA patients were correlated with the levels of C-reactive protein (CRP), erythrocyte sedimentation rate, white blood cell count, and platelet count. Multiple stepwise regression analysis reveals an independent influence of CRP on plasma pentosidine levels. In conclusion, pentosidine levels are significantly higher in plasma and synovial fluid from RA patients and may be useful as a biomarker of chronic inflammation in RA patients.