26 research outputs found

    Coal pump development phase 3

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    Techniques for achieving continuous coal sprays were studied. Coazial injection with gas and pressure atomization were studied. Coal particles, upon cooling, were found to be porous and fragile. Reactivity tests on the extruded coal showed overall conversion to gases and liquids unchanged from that of the raw coal. The potentials for applications of the coal pump to eight coal conversion processes were examined

    Comparison of Three Rat Liver Foci Bioassays - Incidence of Preneoplastic Foci Initiated by Diethylnitrosamine.

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    Three rat liver foci bioassays have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic foci, and by the biochemical determination of alterations in enzyme activities of serum indicating hepatotoxicity. We studied the initiation/promotion schedules according to Oesterle and Deml (A), and according to Pereira (B, Broad Spectrum Protocol), and the initiation/selection protocol according to Tatematsu et al. (C), with diethylnitrosamine (DEN), given as a single initiating dose of 10 and 30 mg/kg body wt respectively. With all schedules Sprague-Dawley rats, either females, 3 weeks old (A), or males, 6 weeks old (B, C) were used. For promotion polychlorinated biphenyls (A) or phenobarbital (B) were administered. Selection was performed with 2-acetylaminofluorene (C). The rats in schemes (B) and (C) underwent partial hepatectomy one day prior to initiation. The number and total area of foci deficient in adenosine-5'-triphosphatase (ATPase) and positive in gamma-glutamyltranspeptidase (GGTase) was evaluated. In the complete schedule with 30 mg of DEN in system (A) foci incidence exceeded that of the other systems by about 7-fold (ATPase) and 2-fold (GGTase) respectively. The lower dose of DEN and all control experiments resulted in a respective lower foci yield. With scheme (C), but not with schemes (A) and (B), e.g. serum fructose-1.6-bisphosphatase and alkaline phosphatase were increased, suggesting liver cell damage. Thus tested with DEN, scheme (A) is most sensitive and causes a low impairment of animals' welfare

    Di(2-ethylhexyl)phthalate alters carbohydrate enzyme activities and foci incidence in rat liver.

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    The effect of di(2-ethylhexyl)phthalate (DEHP) on diethylnitrosamine (DEN)-initiated preneoplastic liver lesions with expression of gamma-glutamyltranspeptidase (GGTase) and loss of adenosine triphosphatase (ATPase) as well as alterations of hepatic carbohydrate metabolism in male and female Sprague-Dawley rats have been investigated. Two treatment schedules have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic islands and by the biochemical determination of alterations in enzyme activities of liver homogenates and of serum, the last indicating hepatotoxicity. For initiation, a single dose of DEN was given, followed by treatment with various doses of DEHP given three times weekly by gavage for 7 or 11 consecutive weeks. As histochemical enzyme markers, the expression of positive GGTase as well as the deficiency in ATPase were used for identification of liver foci. The weanling female rats (protocol A) were found to be more sensitive to the carcinogenic effect of DEN in view of foci incidence than the mature male rats which underwent partial hepatectomy prior to DEN application. The administration of 200 mg DEHP/kg body wt increased the incidence of ATPase-deficient foci in both male and female rats; however, concentrations of 1000 and 2000 mg DEHP/kg decreased the incidence of liver foci. The number of foci with expression of GGTase was only slightly increased in female rats following a DEHP concentration of 50 mg/kg, and 200 mg/kg body wt. DEHP alone did not induce preneoplastic lesions that could be identified by these two markers. Biochemical investigations indicate that DEHP alters the metabolic pattern in liver. An increase of the NADP-linked enzymes glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme, extra-mitochondrial ICDH as well as an enhancement of NAD-dependent α-G3PDH and lactate dehydrogenase were found following DEHP administration. On the other hand the glycolytic enzymes pyruvate kinase (PK) and enolase as well as the gluconeogenetic enzyme fructose-1,6-bisphosphatase (FBPase) were significantly reduced. In protocol B (male rats) the reactions of PK, FBPase and malic enzyme were more altered after DEHP exposure than in protocol A, while the activity of G6PDH was more increased in protocol A. Most enzymes being involved in the carbohydrate metabolism are influenced by DEHP in a dose-dependent manner. There was no increase in serum FBPase activity in both male and female rats after DEHP treatment but a reduction of glutamate-oxalate-transaminase and glutamate-pyruvate-transaminase activities was observed. This and the fact that the control and DEHP-treated animals had similar weight gains indicate that DEHP does not exert a significant hepatotoxicity effect

    Can Biodiversity Data Scientists Document Volunteer and Professional Collaborations and Contributions in the Biodiversity Data Enterprise?

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    The collection, archiving and use of biodiversity data depend on a network of pipelines herein called the Biodiversity Data Enterprise (BDE) and best understood globally through the work of the Global Biodiversity Information Facility (GBIF). Efforts to sustain and grow the BDE require information about the data pipeline and the infrastructure that supports it. A host of metrics from GBIF, including institutional participation (member countries, institutional contributors, data publishers), biodiversity coverage (occurrence records, species, geographic extent, data sets) and data usage (records downloaded, published papers using the data) (Miller 2021), document the rapid growth and successes of the BDE (GBIF Secretariat 2022). Heberling et al. (2021) make a convincing case that the data integration process is working.The Biodiversity Information Standards' (TDWG) Basis of Record term provides information about the underlying infrastructure. It categorizes the kinds of processes*1 that teams undertake to capture biodiversity information and GBIF quantifies their contributions*2 (Table 1). Currently 83.4% of observations come from human observations, of which 63% are of birds. Museum preserved specimens account for 9.5% of records. In both cases, a combination of volunteers (who make observations, collect specimens, digitize specimens, transcribe specimen labels) and professionals work together to make records available.To better understand how the BDE is working, we suggest that it would be of value to know the number of contributions and contributors and their hours of engagement for each data set. This can help the community address questions such as, "How many volunteers do we need to document birds in a given area?" or "How much professional support is required to run a camera trap network?" For example, millions of observations were made by tens of thousands of observers in two recent BioBlitz events, one called Big Day, focusing on birds, sponsored by the Cornell Laboratory of Ornithology and the other called the City Nature Challenge, addressing all taxa, sponsored jointly by the California Academy of Sciences and the Natural History Musuems of Los Angeles County (Table 2). In our presentation we will suggest approaches to deriving metrics that could be used to document the collaborations and contribution of volunteers and staff using examples from both Human Observation (eBird, iNaturalist) and Preserved Specimen (DigiVol, Notes from Nature) record types. The goal of the exercise is to start a conversation about how such metrics can further the development of the BDE

    The E3 ubiquitin ligase UBR5 interacts with the H/ACA ribonucleoprotein complex and regulates ribosomal RNA biogenesis in embryonic stem cells

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    UBR5 is an E3 ubiquitin ligase involved in distinct processes such as transcriptional regulation and development. UBR5 is highly upregulated in embryonic stem cells (ESCs), whereas its expression decreases with differentiation, suggesting a role for UBR5 in ESC function. However, little is known about how UBR5 regulates ESC identity. Here, we define the protein interactome of UBR5 in ESCs and find interactions with distinct components of the H/ACA ribonucleoprotein complex, which is required for proper maturation of ribosomal RNA (rRNA). Notably, loss of UBR5 induces an abnormal accumulation of rRNA processing intermediates, resulting in diminished ribosomal levels. Consequently, lack of UBR5 triggers an increase in p53 levels and a concomitant decrease in cellular proliferation rates. Thus, our results indicate a link between UBR5 and rRNA maturation

    Optimal Nonplanar Escape from Circular Orbits

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