Stable carbon isotope Composition of c9,t11-conjugated linoleic acid in cow's milk as related to dietary fatty acids

This study explores the potential use of stable carbon isotope ratios (delta C-13) of single fatty acids (FA) as tracers for the transformation of FA from diet to milk, with focus on the metabolic origin of c9,t11-18:2. For this purpose, dairy cows were fed diets based exclusively on C-3 and C-4 plants. The FA in milk and feed were fractionated by silver-ion thin-layer chromatography and analyzed for their delta C-13 values. Mean delta C-13 values of FA from C-3 milk were lower compared to those from C-4 milk (-30.1aEuro degrees vs. -24.9aEuro degrees, respectively). In both groups the most negative delta C-13 values of all FA analyzed were measured for c9,t11-18:2 (C-3 milk = -37.0 +/- A 2.7aEuro degrees; C-4 milk -31.4 +/- A 1.4aEuro degrees). Compared to the dietary precursors 18:2n-6 and 18:3n-3, no significant C-13-depletion was measured in t11-18:1. This suggests that the delta C-13-change in c9,t11-18:2 did not originate from the microbial biohydrogenation in the rumen, but most probably from endogenous desaturation of t11-18:1. It appears that the natural delta C-13 differences in some dietary FA are at least partly preserved in milk FA. Therefore, carbon isotope analyses of individual FA could be useful for studying metabolic transformation processes in ruminants.

Dense Concrete Layer as Top Course of Bridge Deck Construction, HR-502, 1990

The use of deicing salts in this part of the country is a necessity to remove ice from our bridges. The use of these salts has always been a problem since the chloride-ions penetrate the concrete and reach the steel and cause corrosion which eventually cause deterioration of both the steel and concrete. One method used to try to prevent this from happening was to apply a waterproof membrane to the concrete after it was placed. This method did help, but was not cost effective as the longevity of the membrane system was of relatively short duration. For this reason, this research project was initiated. After the original deck was placed a second layer of concrete about 1 1/2" thick was placed on top. Biennial evaluation of the decks included testing for delaminations and steel corrosion. Cores were also obtained for a chloride analysis. Testing and observations showed the two-layer bridge deck to be effective in preventing corrosion. Since the time this project was initiated, epoxy steel has been introduced and is a cost effective way to protect the steel from corrosion.

Role of reactive hyperreninemia in blood pressure changes induced by sodium depletion in patients with refractory hypertension

Sixteen patients with refractory hypertension were submitted to vigorous sodium depletion while cardiovascular homeostasis was monitored with measurements of hormonal and hemodynamic parameters and repeat saralasin tests. This regimen resulted in a negative sodium balance by an average of 300 mEq. The loss of sodium closely correlated to the decrease of body weight (r = 0.70, p less than 0.005). Blood pressure (BP) decreased from 176/166 +/- 8/3 to 155/109 +/-6/3 mm Hg. There was a significant correlation between percent increments in plasma renin activity (PRA) and the rise in plasma norepinephrine (r = 0.68, p less than 0.05) and a close negative correlation between percent increase in PRA and the ratio of fall in mean blood pressure (MAP) per unit of weight loss (r = -0.73, p less than 0.005). Thus, patients with the least percent increase in PRA demonstrated the greatest fall in BP per unit of weight loss, indicating that relative rather than absolute elevation of renin may be the factor limiting antihypertensive efficacy of sodium depletion. Sodium depletion induced increase in peripheral resistance and decrease in cardiac output, both mostly attributable to relative hyperreninemia. Indeed, the adverse hemodynamic changes were reversed by angiotensin inhibition, during which BP normalized. It is concluded that vigorous sodium depletion complemented by angiotensin blockade or suppression with sympatholytic agents improves management of otherwise refractory hypertension.

Filamin depletion blocks endoplasmic spreading and destabilizes force-bearing adhesions

Cell motility is an essential process that depends on a coherent, cross-linked actin cytoskeleton that physically coordinates the actions of numerous structural and signaling molecules. The actin cross-linking protein, filamin (Fln), has been implicated in the support of three-dimensional cortical actin networks capable of both maintaining cellular integrity and withstanding large forces. Although numerous studies have examined cells lacking one of the multiple Fln isoforms, compensatory mechanisms can mask novel phenotypes only observable by further Fln depletion. Indeed, shRNA-mediated knockdown of FlnA in FlnB¿/¿ mouse embryonic fibroblasts (MEFs) causes a novel endoplasmic spreading deficiency as detected by endoplasmic reticulum markers. Microtubule (MT) extension rates are also decreased but not by peripheral actin flow, because this is also decreased in the Fln-depleted system. Additionally, Fln-depleted MEFs exhibit decreased adhesion stability that appears in increased ruffling of the cell edge, reduced adhesion size, transient traction forces, and decreased stress fibers. FlnA¿/¿ MEFs, but not FlnB¿/¿ MEFs, also show a moderate defect in endoplasm spreading, characterized by initial extension followed by abrupt retractions and stress fiber fracture. FlnA localizes to actin linkages surrounding the endoplasm, adhesions, and stress fibers. Thus we suggest that Flns have a major role in the maintenance of actin-based mechanical linkages that enable endoplasmic spreading and MT extension as well as sustained traction forces and mature focal adhesions.

Summer ozone cycles in the Lisbon metropolitan area and its relation to some meteorological variables

The aim of this work is to study the tropospheric ozone concentrations and daily peak cycles in the Lisbon MetropolitanArea (LMA) during the summer season (June, July and August, JJA) covering the 4-yr study period 2002-2005. Theresults show that all the stations have the same pattern: a minimum in the early morning followed by an increase at 1000UTC reaching to a peak at 1300-1400 UTC, dropped again to minimum values 1800 UTC but with different concentrationsdue to regional and local wind circulations and complex dynamic interactions. We identified in Lisbon city the ozone “weekendeffect”. Finally, we studied an episode of very high levels of tropospheric ozone and related daily ozone concentrationswith some meteorological variables.

Impact of 3 different short-term chemotherapy regimens on lymphocyte-depletion and reconstitution in melanoma patients.

Recent immunotherapy trials have shown that lymphodepletion induced by short-term chemotherapy favors subsequent expansion of adoptively transferred T cells, by homeostatic mechanisms. To take advantage of this effect, novel regimens are being developed with the aim to enhance tumor immunity and reduce treatment toxicity. We have designed a clinical phase I trial combining chemotherapy, reinfusion of PBMC containing Melan-A(MART-1)-specific T cells, and vaccination with Melan-A peptide in Incomplete Freund's Adjuvant. Treatment with Busulfan plus Fludarabine depleted lymphocytes only weakly. Cyclophosphamide (CTX) plus Fludarabine depleted lymphocytes more profoundly, with a maximal effect using high doses of CTX. It is interesting to note that, the degree of homeostatic T-cell proliferation correlated tightly with the extent of lymphodepletion. As compared with CD4 T cells, CD8 T cells showed higher susceptibility to chemotherapy, followed by more rapid homeostatic proliferation and recovery, resulting in strong inversions of CD4/CD8 ratios. Despite efficient homeostatic proliferation of total CD4 and CD8 T cells, the frequency of CD8 T cells specific for Melan-A and cancer-testis antigens remained relatively low. In contrast, EBV-specific T cells expanded and reached high numbers. We conclude that short-term chemotherapy promoted homeostatic lymphocyte proliferation depending on the intensity of lymphocyte depletion, however without preferential expansion of tumor antigen-specific T cells.

CD4+CD25+ T cell depletion impairs tolerance induction in a murine model of asthma.

BACKGROUND: Regulatory T cells (Tregs) are key players in controlling the development of airway inflammation. However, their role in the mechanisms leading to tolerance in established allergic asthma is unclear. OBJECTIVE: To examine the role of Tregs in tolerance induction in a murine model of asthma. METHODS: Ovalbumin (OVA) sensitized asthmatic mice were depleted or not of CD25(+) T cells by anti-CD25 PC61 monoclonal antibody (mAb) before intranasal treatment (INT) with OVA, then challenged with OVA aerosol. To further evaluate the respective regulatory activity of CD4(+)CD25(+) and CD4(+)CD25(-) T cells, both T cell subsets were transferred from tolerized or non-tolerized animals to asthmatic recipients. Bronchoalveolar lavage fluid (BALF), T cell proliferation and cytokine secretion were examined. RESULTS: Intranasal treatment with OVA led to increased levels of IL-10, TGF-beta and IL-17 in lung homogenates, inhibition of eosinophil recruitment into the BALF and antigen specific T cell hyporesponsiveness. CD4(+)CD25(+)Foxp3(+) T cells were markedly upregulated in lungs and suppressed in vitro and in vivo OVA-specific T cell responses. Depletion of CD25(+) cells before OVA INT severely hampered tolerance induction as indicated by a strong recruitment of eosinophils into BALF and a vigorous T cell response to OVA upon challenge. However, the transfer of CD4(+)CD25(-) T cells not only suppressed antigen specific T cell responsiveness but also significantly reduced eosinophil recruitment as opposed to CD4(+)CD25(+) T cells. As compared with control mice, a significantly higher proportion of CD4(+)CD25(-) T cells from OVA treated mice expressed mTGF-beta. CONCLUSION: Both CD4(+)CD25(+) and CD4(+)CD25(-) T cells appear to be essential to tolerance induction. The relationship between both subsets and the mechanisms of their regulatory activity will have to be further analyzed.

JXTAnonym: An anonymity layer for JXTA services messaging

With the evolution of the P2P research eld, new problems, such as those related with information security, have arisen. It is important to provide security mechanisms to P2P systems, since it has already become one of the key issues when evaluating them. However, even though many P2P systems have been adapted to provide a security baseline to their underlying applications, more advanced capabilities are becoming necessary. Speci cally, privacy preservation and anonymity are deemed essential to make the information society sustainable. Unfortunately, sometimes, it may be di cult to attain anonymity unless it is included into the system's initial design. The JXTA open protocols speci cation is a good example of this kind of scenario. This work studies how to provide anonymity to JXTA's architecture in a feasible manner and proposes an extension which allows deployed services to process two-way messaging without disclosing the endpoints'identities to third parties.

A robust audio watermarking scheme based on MPEG 1 Layer 3 Compression

This paper describes an audio watermarking scheme based on lossy compression. The main idea is taken from an image watermarking approach where the JPEG compression algorithm is used to determine where and how the mark should be placed. Similarly, in the audio scheme suggested in this paper, an MPEG 1 Layer 3 algorithm is chosen for compression to determine the position of the mark bits and, thus, the psychoacoustic masking of the MPEG 1 Layer 3compression is implicitly used. This methodology provides with a high robustness degree against compression attacks. The suggested scheme is also shown to succeed against most of the StirMark benchmark attacks for audio.

A security layer for JXTA core protocols

JXTA define un conjunto de seis protocolos básicos especialmente adecuados para una computación ad hoc, permanente, multi-hop, peer-to-peer (P2P). Estos protocolos permiten que los iguales cooperen y formen grupos autónomos de pares. Este artículo presenta un método que proporciona servicios de seguridad en los protocolos básicos: protección de datos, autenticidad, integridad y no repudio. Los mecanismos que se presentan son totalmente distribuidos y basados ¿¿en un modelo puro peer-to-peer, que no requieren el arbitraje de un tercero de confianza o una relación de confianza establecida previamente entre pares, que es uno de los principales retos en este tipo de entornos.