131 research outputs found

    Radiant Heat Effects on Ceramic Artifacts from the American Southwest: From Experimental Results to Site Treatment Guidelines

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    Archaeological assemblages in the American Southwest are currently subjected to periodic wildfires and prescribed burns, and have been exposed to fires in the past. Ceramics are a key constituent of these assemblages, leading to questions regarding the effects of post-depositional heat exposure on pottery. Alterations of ceramic surface appearance and other attributes have been observed following wildfires, and such changes are significant because intact ceramics provide important temporal context and social information. Over the past 150 years, southwestern wildfires have shifted away from the historical high-frequency, low-severity regime; thus, cultural resources can be exposed to fires that are potentially more damaging than have occurred in the past. The range of fire environments and the duration and intensity of heating that result in damages to ceramic artifacts have not been previously systematically assessed. Results from laboratory tests conducted as part of the Joint Fire Science Program-funded ArcBurn project demonstrate that radiant heat fire environments, sustained dose, and ceramic category are important determinates for predicting the patterns of alteration. Results can be used to identify fire environments that cause loss of cultural information from artifact assemblages in order to develop management treatments and procedures to guide archaeological preservation in fire-prone landscapes

    Suitability of Different PCR-DGGE Primer Sets for the Monitoring of Lactic Acid Bacteria in Wine

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    Lactic acid bacteria (LAB) play a dual role in winemaking as they are the main effectors of malolactic fermentation, but some members can also cause wine spoilage. PCR-DGGE has proved to be a quick tool to study the LAB community and their fluctuation in wine. For detecting wine-associated LAB by PCR-DGGE, the primer sets WLAB1/WLAB2GC, WBAC1/WBAC2GC, Lac1/Lac1o/Lac2GC, 341fGC/518r and rpoB1/rpoB1o/rpoB2GC were tested and evaluated in this study. The primer systems were assessed by the separation of LAB reference strains on DGGE gels and by attributing the resulting amplicons to defined species. Subsequently, the detection of LAB in wine samples and enrichments thereof was compared. While the primer systems WBAC1/WBAC2GC and 341fGC/518r were not appropriate, the Lac1/Lac1o/Lac2GC primer set performed well. However, multiple bands complicated the evaluation. The rpoB1/rpoB1o/rpoB2GC set seemed to be promising for the detection of LAB in wine, although further improvements in terms of the detection limit need to be done. Due to the pronounced sensitivity and the sufficient discrimination of LAB at species level, the WLAB1/WLAB2GC primer system was found to be most suitable for studying the occurrence of LAB in wine

    Circadian rhythm of hepatic cytosolic and nuclear estrogen receptors

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    The distribution of estrogen receptor between the cytosolic and nuclear compartments were evaluated in liver of male rats to determine whether a circadian rhythm exists. Cytosolic receptor reached a maximum level at 400 hours and a minimum at 2000 and 2400 hr. Nuclear receptor reached a maximum level at 800 hr and was lowest at 1600 and 2000 hr. Serum estradiol levels were also highest at 800 hr and lowest at 1600 hr. The variations in cytosolic and nuclear receptors are not reciprocal; in fact, the overall content of receptor in the liver is not constant and also displays a circadian rhythm. © 1986 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

    Effect of tamoxifen on hepatic regeneration in male rats

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    A number of metabolic changes within the liver occur concurrent with hepatic regeneration. These processes suggest that the administration of an antiestrogen might alter the rate of hepatic regeneration. To examine this question, male Wistar rats were treated with tamoxifen (0.1 mg/rat/day or 1.0 mg/rat/day) or vehicle for three days prior to and after partial hepatectomy, and the anatomic and biochemical process of hepatic regeneration was assessed. Tamoxifen administration caused a dose-dependent decrease in the hepatic cytosolic estrogen receptor activity and, conversely, a dose-dependent increase in cytosolic androgen receptor activity. Despite these changes in baseline hepatic sex steroid receptor status, all receptor activities were comparable between the three groups within 24 hr of partial hepatectomy. Moreover, no differences in any of the the parameters assessing hepatic regeneration following partial hepatectomy were evident: liver-body ratio, ornithine decarboxylase activity, and thymidine kinase activity. This lack of effect of tamoxifen treatment on hepatic regeneration suggests either that estrogens do not play a role in the modulation of liver growth after partial hepatectomy or that, once initiated, the regenerative process per se determines a series of events that regulate hepatocellular sex hormone receptor status independent of extrahepatic stimuli. © 1989 Plenum Publishing Corporation

    Serum osteoprotegerin is associated with pulse pressure in kidney transplant recipients

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    Pulse pressure (PP) reflects increased large artery stiffness, which is caused, in part, by arterial calcification in patients with chronic kidney disease. PP has been shown to predict both cardiovascular and cerebrovascular events in various patient populations, including kidney transplant (KTX) recipients. Osteoprotegerin (OPG) is a marker and regulator of arterial calcification, and it is related to cardiovascular survival in hemodialysis patients. Here we tested the hypothesis that OPG is associated with increased pulse pressure. We cross-sectionally analyzed the association between serum OPG and PP in a prevalent cohort of 969 KTX patients (mean age: 51 +/- 13 years, 57% male, 21% diabetics, mean eGFR 51 +/- 20 ml/min/1.73 m2). Independent associations were tested in a linear regression model adjusted for multiple covariables. PP was positively correlated with serum OPG (rho = 0.284, p < 0.001). Additionally, a positive correlation was seen between PP versus age (r = 0.358, p < 0.001), the Charlson Comorbidity Index (r = 0.232, p < 0.001), serum glucose (r = 0.172, p < 0.001), BMI (r = 0.133, p = 0.001) and serum cholesterol (r = 0.094, p = 0.003). PP was negatively correlated with serum Ca, albumin and eGFR. The association between PP and OPG remained significant after adjusting for multiple potentially relevant covariables (beta = 0.143, p < 0.001). We conclude that serum OPG is independently associated with pulse pressure in kidney transplant recipients

    PI3Kinase signaling in glioblastoma

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    Glioblastoma (GBM) is the most common primary tumor of the CNS in the adult. It is characterized by exponential growth and diffuse invasiveness. Among many different genetic alterations in GBM, e.g., mutations of PTEN, EGFR, p16/p19 and p53 and their impact on aberrant signaling have been thoroughly characterized. A major barrier to develop a common therapeutic strategy is founded on the fact that each tumor has its individual genetic fingerprint. Nonetheless, the PI3K pathway may represent a common therapeutic target to most GBM due to its central position in the signaling cascade affecting proliferation, apoptosis and migration. The read-out of blocking PI3K alone or in combination with other cancer pathways should mainly focus, besides the cytostatic effect, on cell death induction since sublethal damage may induce selection of more malignant clones. Targeting more than one pathway instead of a single agent approach may be more promising to kill GBM cells
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