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Sample records for bullhead city az

  1. 78 FR 34300 - Safety Zone; Bullhead City Regatta, Bullhead City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ...The Coast Guard is proposing a temporary safety zone on the navigable waters of the Colorado River in Bullhead City, Arizona for the Bullhead City Regatta on August 10, 2013. This temporary safety zone is necessary to provide for the safety of the participants, crew, spectators, participating vessels, and other vessels and users of the waterway. Persons and vessels would be prohibited from......

  2. 77 FR 36439 - Safety Zone; Bullhead City Regatta; Bullhead City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). 4. Public Meeting We... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bullhead City Regatta; Bullhead City,...

  3. 76 FR 38568 - Safety Zone; Bullhead City Regatta, Bullhead City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ...The Coast Guard is establishing a temporary safety zone on the navigable waters of the Colorado River in Bullhead City, Arizona for the Bullhead City Regatta on August 13, 2011. This temporary safety zone is necessary to provide for the safety of the participants, crew, spectators, participating vessels, and other vessels and users of the waterway. Persons and vessels would be prohibited from......

  4. 78 FR 44011 - Safety Zone; Bullhead City Regatta; Bullhead City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    .... SUPPLEMENTARY INFORMATION: ] Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM... Proposed Rulemaking for this event on June 7, 2013 (78 FR 34300). We received no comments or requests for a... waterway. Persons and vessels are prohibited from entering into, transiting through or anchoring...

  5. 77 FR 70121 - Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...

  6. 78 FR 13811 - Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...

  7. 33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Annual Firework Events on the... § 165.1124 Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and... § 165.1124 1. Avi Resort & Casino Memorial Day Fireworks Sponsor Avi Resort & Casino. Event...

  8. 33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Annual Firework Events on the... § 165.1124 Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and... § 165.1124 1. Avi Resort & Casino Memorial Day Fireworks Sponsor Avi Resort & Casino. Event...

  9. 78 FR 48303 - Establishment of Class E Airspace; Tuba City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... Tuba City VORTAC, Tuba City, AZ (78 FR 32086, May 29, 2013). In the regulatory text, the region..., 2013 (78 FR 32086), Airspace Docket No. 13-AWP-1, FR Doc. 2013-12623, is corrected as follows: Sec. 71..., AZ . Issued in Seattle, Washington, on July 29, 2013. Christopher Ramirez, Manager,...

  10. 78 FR 16823 - Proposed Establishment of Class E Airspace; Tuba City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... Tactical Air Navigational Aid (VORTAC), Tuba City, AZ to facilitate vectoring of Instrument Flight Rules (IFR) aircraft under control of Denver, Albuquerque and Salt Lake City Air Route Traffic Control... AIRSPACE AREAS; AIR TRAFFIC SERVICE ROUTES; AND REPORTING POINTS 0 1. The authority citation for 14...

  11. 33 CFR 100.1102 - Annual Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... application each year in accordance with 33 CFR 100.15 to the cognizant Coast Guard Sector Commander no less... the Roadrunner Resort and Headgate Dam). 12. BlueWater Resort and Casino Thanksgiving Regatta Sponsor... Sunday during Thanksgiving week. Location Parker, AZ. Regulated Area The Lake Moovalya area of...

  12. 78 FR 32086 - Establishment of Class E Airspace; Tuba City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... INFORMATION: History On March 19, 2013, the FAA published in the Federal Register a notice of proposed rulemaking (NPRM) to amend controlled airspace at Tuba City, AZ (78 FR 16823). Interested parties were... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR...

  13. 78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ... temporary safety zone within the navigable waters of Lake Havasu and the London Bridge Channel for the Lake... Triathlon will consist of 600 participants. The waterside swim course consists of 1500 meters in Lake...

  14. 78 FR 17869 - Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-25

    ... FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History and Information The... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Desert Storm Shootout; Lake Havasu, Lake... City, Arizona in support of the Desert Storm Shootout. This temporary safety zone is necessary...

  15. Brown bullhead (Ameiurus nebulosus) skin carcinogenesis.

    PubMed

    Bunton, T E

    2000-06-01

    Alternative models using fish species have been tested in liver toxicity and carcinogenesis bioassays. Similar models have not been developed for skin. The brown bullhead (Ameiurus nebulosus) has shown potential as a model for skin carcinogenesis studies due to its sensitivity to environmental chemical pollutants. The present study is an initial morphologic and biochemical characterization of the normal and neoplastic brown bullhead skin to assess its suitability as a model of skin carcinogenesis. Brown bullhead were removed from Back River in the Chesapeake Bay region, an area historically polluted with heavy metals and polycyclic aromatic hydrocarbons. Histology, histochemistry, and electron microscopy were used to stage the morphologic development and progression of neoplasia in skin. The distribution of keratin, a family of structural proteins with altered expression in mammalian tumorigenesis, was analyzed with one and two dimensional gel electrophoresis and nitrocellulose blots of extracts from normal skin. Keratin expression in skin and other organs was also assessed with immunohistochemistry using AE1, AE3, and PCK 26 antibodies, and the proliferation index in skin and neoplasms with PCNA antibody. Skin lesions appeared to progress from hyperplasia through carcinoma, and the proliferation index was increased in papilloma. Also in papilloma, intercellular interdigitations appeared increased and desmosomes decreased which may in future studies correlate with changes in expression of other molecular markers of neoplastic progression. Both Type I and Type II keratin subfamilies were detected in skin using gel electrophoresis with the complimentary keratin blot-binding assay. For further development of the brown bullhead model, future studies can compare and relate these baseline data to alterations in expression of keratin and other markers in fish neoplasms and to molecular events which occur in man. PMID:10930121

  16. HISTORICAL MONITORING OF BIOMARKERS OF EXPOSURE OF BROWN BULLHEAD

    EPA Science Inventory

    Biomarkers of exposure to chemical contamination, benzo(a)pyrene (BAP) and naphthalene (NAPH) type metabolites were measured in brown bullhead from a heavily polycyclic aromatic hydrocarbon (PAH) contaminated section of the Black River, Ohio during and immediately after remedial ...

  17. Metabolism of phenanthrene by brown bullhead liver microsomes.

    PubMed

    Pangrekar, Jyotsna; Kole, Panna L; Honey, Sangeet A; Kumar, Subodh; Sikka, Harish C

    2003-09-10

    We have investigated the regio- and stereoselective metabolism of phenanthrene by the liver microsomes of brown bullhead (Ameriurus nebulosus), a bottom dwelling fish species. The liver microsomes from untreated and 3-methylcholanthrene (3-MC)-treated brown bullheads metabolized phenanthrene at a rate of 14.1 and 20.7 pmol/mg protein/min, respectively, indicating that the hydrocarbon is a rather poor substrate for bullhead liver microsomes contrary to what has been reported for rat liver microsomes. The major phenanthrene metabolites formed by liver microsomes from untreated and 3-MC-treated bullheads included benzo-ring 1,2-dihydrodiol (25.3 and 11.6%), K-region 9,10-dihydrodiol (9.6 and 9.6%), and phenols (40.5 and 54.5%). The 3,4-dihydrodiol represented a minor proportion of the total phenanthrene metabolites. The low proportion of the 9,10-dihydrodiol formed by both control and 3-MC-treated bullhead microsomes sharply contrasts the previous data reported for the corresponding rat liver microsomes which metabolized phenanthrene predominantly to its 9,10-dihydrodiol representing 76.6 and 67.1%, respectively of the total metabolites. Liver microsomes from 3-MC-treated bullheads, like rat liver microsomes, were more selective in their attack at the 1,2-position of the benzo-ring than at the 3,4-position of the benzo-ring. Phenanthrene 1,2-dihydrodiol and 3,4-dihydrodiol formed by liver microsomes from both control and 3-MC-treated bullheads consisted predominantly of their R,R enantiomer. Phenanthrene, compared with benzo[a]pyrene and chrysene, is metabolized by bullhead liver microsomal enzymes to its benzo-ring dihydrodiols with a relatively low degree of stereoselectivity.

  18. DNA DAMAGE AND EXTERNAL LESIONS IN BROWN BULLHEAD FROM CONTAMINATED HABITATS

    EPA Science Inventory

    The single cell gel electrophoresis ("Comet") assay was used to compare levels of DNA damage in brown bullheads (Ameiurus nebulosus) collected from three known contaminated locations, the Cuyahoga River, Ashtabula River, and Ashumet Pond (Cape Cod), with brown bullheads collected...

  19. Temperature-dependent Index of Mitotic Interval (τ0) for Chromosome Manipulation in Korean Bullhead, Pseudobagrus fulvidraco

    PubMed Central

    Lim, Sang Gu; Han, Hyoung Kyun; Gil, Hyun Woo; Park, In-Seok

    2012-01-01

    Korean bullhead (Pseudobagrus fulvidraco) was collected from the Kum River areas of Kangkyung-eup, Nonsan city, Chungcheongnam-do, Korea, from April to June, 2012 and was fertilized in order to observe egg development and temperature-related cleavage rates and mitotic intervals (τ0). The fertilized eggs were separative, demersal and light yellowish with 1.5±0.06 mm in diameter, and did not contain oil globules. The first cleavage stages were 90 min, 80 min, 60 min and 50 min at 21°C , 24°C , 27°C and 30°C , respectively. At higher temperatures, eggs developed faster and underwent further identical development. For Korean bullhead, τ0 were 33.4±2.08 min at 21°C, 31.5±3.06 min at 24°C, 28.1±2.11 min at 27°C and 26.4±3.35 min at 30°C . There were strong negative correlations between the τ0 and water temperatures at all points studied (Y= 1.13X+58.15, R2=0.98, n=30, where Y is τ0 and X is temperature). The results obtained in this work will be helpful for chromosome manipulation by use of cleavage frequency data and τ0 data in Korean bullhead. PMID:25949107

  20. 78 FR 71706 - Noise Exposure Map Notice for Laughlin/Bullhead International Airport, Bullhead City, Arizona

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... future noise contours. Arrival and departure flight tracks for the existing and five-year forecast Noise... noise exposure contours depicted on a noise exposure map submitted under section 47503 of the Act, it... properties with regard to the depicted noise contours, or in interpreting the noise exposure maps to...

  1. Metabolism of chrysene by brown bullhead liver microsomes.

    PubMed

    Pangrekar, Jyotsna; Kole, Panna L; Honey, Sangeet A; Kumar, Subodh; Sikka, Harish C

    2003-01-01

    We have investigated the regio- and stereoselective metabolism of chrysene, a four-ring symmetrical carcinogenic polycyclic aromatic hydrocarbon (PAH), by the liver microsomes of brown bullhead (Ameriurus nebulosus), a bottom-dwelling fish species. The liver microsomes from untreated and 3-methylcholanthrene (3-MC)-treated brown bullheads metabolized chrysene at the rate of 30.1 and 82.2 pmol/mg protein/min, respectively. Benzo-ring diols (1,2-diol and 3,4-diol) were the major chrysene metabolites formed by liver microsomes from control and 3-MC-treated fish. However, the control microsomes produced a considerably higher proportion of chrysene 1,2-diol (benzo-ring diol with a bay region double bond) plus 1-hydroxychrysene, than 3,4-diol plus 3-hydroxychrysene, indicating that these microsomes are selective in attacking the 1,2- position of the benzo-ring. On the other hand, 3-MC-induced microsomes did not show such a regioselectivity in the metabolism of chrysene. Control bullhead liver microsomes, compared to control rat liver microsomes, produced a considerably higher proportion of chrysene 1,2-diol, the putative proximate carcinogenic metabolite of chrysene. Like rat liver microsomes, bullhead liver microsomes produced only trace amounts of the K-region diol. Chrysene 1,2-diol and 3,4-diol formed by the liver microsomes from both control and 3-MC-treated bullheads consisted predominantly of their R,R-enantiomers. Chrysene is metabolized by bullhead liver microsomal enzymes to its benzo-ring diols with a relatively lower degree of stereoselectivity compared to benzo[a]pyrene (a five-ring PAH), but with a higher degree of stereoselectivity compared to phenanthrene (a three-ring PAH). The data of this study, together with those from our previous studies with phenanthrene, benzo[a]pyrene and dibenzo[a,l]pyrene (a six-ring PAH), indicate that the regioselectivity in the metabolism of PAHs by brown bullhead and rainbow trout liver microsomes does not vary greatly with

  2. Biotic and abiotic correlates with black bullhead population characteristics in Nebraska sandhill lakes

    USGS Publications Warehouse

    Phelps, Q.E.; Ward, M.J.; Paukert, C.P.; Chipps, S.R.; Willis, D.W.

    2005-01-01

    We explored relationships among black bullhead (Ameiurus melas) population characteristics and physicochemical attributes in shallow lakes and quantified relationships between population characteristics of black bullhead and sport fishes. Lake characteristics and fisheries survey data were collected from the Sandhills region of northcentral Nebraska from May through June, 1998 and 1999. Relative abundance of black bullheads was inversely related to proportional stock density (r=-0.672, df=15, P=0.004); however, neither relative weight nor growth was significantly (P ??? 0.20) related to black bullhead relative abundance. Population characteristics of common panfish species such as bluegill (Lepomis macrochirus), green sunfish (L. cyanellus), pumpkinseed (L. gibbosus), and yellow perch (Perca flavescens) were not correlated with black bullhead relative abundance or size structure. Rather, proportional stock density (r=0.655, df=10, P=0.029) and growth (r=0.59, df=11, P=0.04) of black bullhead were positively related to relative abundance of largemouth bass (Micropterus salmoides). Similarly, black bullhead relative abundance was inversely related to largemouth bass size structure (r=-0.51, df=14, P= 0.05). Black bullhead mean length at age 3 was positively related to total phosphorous concentration (r=0.65, df=16, P=0.004), and bullhead relative abundance was positively related to shoreline development index (r=0.46, df=22, P=0.03). Population characteristics of black bullhead appeared to have little influence on panfish communities. Rather, black bullhead abundance, predator density, and lake productivity exhibited stronger relationships with black bullhead population characteristics.

  3. DNA DAMAGE AND EXTERNAL LESIONS IN BROWN BULLHEADS FROM CONTAMINATED HABITATS

    EPA Science Inventory

    The Comet assay was used to compare levels of DNA damage in brown bullheads (Ameiurus nebulosus) collected from three known contaminated locations, the Cuyahoga River, Ashtabula River, and Ashumet Pond (Cape Cod), with brown bullheads collected from three paired reference sites, ...

  4. Comparative metabolism of benzo[a]pyrene by liver microsomes of channel catfish and brown bullhead

    SciTech Connect

    Yuan, Z.X.; Kumar, S.; Sikka, H.C.

    1997-04-01

    The authors investigated the metabolism of the carcinogen benzo[a]pyrene (BaP) by liver microsomes of channel catfish (Ictalurus punctatus) and brown bullhead (Ameiurus nebulosus) pretreated with 3-methylcholanthrene. The catfish liver microsomes metabolized BaP at a considerably lower rate than did the brown bullhead liver microsomes. Although the BaP metabolites produced by the liver microsomes of the two species were qualitatively similar, there were considerable differences in the relative proportions of individual metabolites formed. The catfish liver microsomes produced a considerably lower proportion of benzo-ring diols of BaP including BaP-7,8-diol (the proximate carcinogenic metabolite of BaP) than did the bullhead liver microsomes. Compared to the bullhead liver microsomes, the catfish microsomes converted a higher proportion of BaP to phenolic metabolites.

  5. The riddle of hepatic neoplasia in brown bullheads from relatively unpolluted waters in New York State.

    PubMed

    Spitsbergen, J M; Wolfe, M J

    1995-01-01

    Since 1985, pathologists at Cornell University have investigated the causes of lesions in freshwater fish throughout New York waters in order to clarify possible impairment of fish health by environmental contaminants. Fishermen and biologists alerted us to several relatively protected reservoirs and ponds in which we have found no evidence of elevated levels of anthropogenic environmental contaminants but in which up to 100% of brown bullheads exhibited skin neoplasia. Complete necropsies and histologic study revealed that over 30% of mature brown bullheads from some of these sites had benign or malignant hepatocellular or biliary liver neoplasia. Up to 50% of brown bullheads had benign or malignant liver neoplasia in other relatively unpolluted waters with no evidence of skin neoplasia in bullheads. Multiple samplings of brown bullheads from several of these sites have revealed puzzling variability in the prevalence of skin, liver, and other neoplasia in these fish populations. The cause of these striking epizootics of neoplasia in brown bullheads in unpolluted waters in New York State remains unclear. We hypothesize that natural carcinogens such as N-nitroso compounds formed in aquatic sediments or radon from geologic formations may contribute to epizootic fish neoplasia in New York waters. PMID:8772257

  6. In vitro kinetics of hepatic glutathione s-transferase conjugation in largemouth bass and brown bullheads

    SciTech Connect

    Gallagher, E.P.; Sheehy, K.M.; Lame, M.W.; Segall, H.J.

    2000-02-01

    The kinetics of glutathione 5-transferase (GST) catalysis were investigated in largemouth bass (Micropterus salmoides) and brown bullheads (Amerius nebulosus), two freshwater fish species found in a variety of polluted waterways in the eastern US. The initial rates of hepatic GST activity toward four GST substrates, including 1-chloro-2,4-dinitrobenzene, ethacrynic acid, {Delta}5-androstene-17-dione, and nitrobutyl chloride, were significantly higher in brown bullheads than in largemouth bass. Hepatic GST activity toward 1,2-dichloro-4-nitrobenzene, a {mu}-class GST substrate in rodents, was not detectable in either species. Liver cytosolic GSTs were more efficient in bullheads than in bass at catalyzing 1-chloro-2,4-dinitrobenzene-reduced glutathione (CDNB-GSH) conjugation over a broad range of electrophile (CDNB) concentrations, including those representative of environmental exposure. In contrast, largemouth bass maintained higher ambient concentrations of GSH, the nucleophilic cofactor for GST-mediated conjugation, than brown bullheads. Biphasic kinetics for GST-CDNB conjugation under conditions of variable GSH concentration were apparent in Eadie-Hofstee plots of the kinetic data, suggesting the presence of at least two hepatic GST isozymes with markedly different K{sub m} values for GSH in both species. The GST-CDNB reaction rate data obtained under conditions of variable GSH were well fitted (R{sup 2} = 0.999) by the two-enzyme Michaelis-Menten equation. In addition, Western blotting experiments confirmed the presence of two different hepatic GST-like proteins in both largemouth bass and brown bullhead liver. Collectively, these findings indicate that largemouth bass and brown bullhead GSTs catalyze the conjugation of structurally diverse, class-specific GST substrates, and that brown bullheads exhibit higher initial rates of GST activity than largemouth bass. The relatively higher rates of in vitro liver GST activity at the low substrate concentrations

  7. Decreased glutathione S-transferase expression and activity and altered sex steroids in Lake Apopka brown bullheads (Ameriurus nebulosus)

    USGS Publications Warehouse

    Gallagher, E.P.; Gross, T.S.; Sheehy, K.M.

    2001-01-01

    A number of freshwater lakes and reclaimed agricultural sites in Central Florida have been the receiving waters for agrochemical and municipal runoff. One of these sites, Lake Apopka, is also a eutrophic system that has been the focus of several case studies reporting altered reproductive activity linked to bioaccumulation of persistent organochlorine chemicals in aquatic species. The present study was initiated to determine if brown bullheads (Ameriurus nebulosus) from the north marsh of Lake Apopka (Lake Apopka Marsh) exhibit an altered capacity to detoxify environmental chemicals through hepatic glutathione S-transferase (GST)-mediated conjugation as compared with bullheads from a nearby reference site (Lake Woodruff). We also compared plasma sex hormone concentrations (testosterone, 17-?? estradiol, and 11 keto-testosterone) in bullheads from the two sites. Female bullheads from Lake Apopka had 40% lower initial rate GST conjugative activity toward 1-chloro-2,4-dinitrobenzene (CDNB), 50% lower activity towards p-nitrobutyl chloride (NBC), 33% lower activity toward ethacrynic acid (ECA), and 43% lower activity toward ??5-androstene-3,17-dione (??5-ADI), as compared with female bullheads from Lake Woodruff. Enzyme kinetic analyses demonstrated that female bullheads from Lake Apopka had lower GST-catalyzed CDNB clearance than did female Lake Woodruff bullheads. Western blotting studies of bullhead liver cytosolic proteins demonstrated that the reduced GST catalytic activities in female Lake Apopka bullheads were accompanied by lower expression of hepatic GST protein. No site differences were observed with respect to GST activities or GST protein expression in male bullheads. Female Lake Apopka bullheads also had elevated concentrations of plasma androgens (testosterone and 11-ketotestosterone) as compared with females from Lake Woodruff. In contrast, male Lake Apopka bullheads had elevated levels of plasma estrogen but similar levels of androgens as compared with

  8. The effect of contaminated sediments on fecundity of the brown bullhead in three Lake Erie tributaries

    USGS Publications Warehouse

    Lesko, Lynn T.; Smith, Stephen B.; Blouin, Marc A.

    1996-01-01

    Female brown bullhead (Ameiurus nebulosus) were collected from three Lake Erie tributaries (Ohio) from 8 to 25 May 1989, to determine the effects of contaminated sediments on reproductive potentials. Fish obtained from the Black and Cuyahoga rivers, which contain sediments with elevated concentrations of metals, PCBs, and PAHs, were compared with fish collected in Mud Brook, a tributary of the Huron River, which was selected as our reference site. Fecundity, egg diameter, fish length and weight, and the presence of external abnormalities were recorded for each fish. Brown bullhead from the contaminated sites were larger then those from the reference site and fecundity was significantly (P < 0.05) different in all three river systems. Those from the most polluted river (Cuyahoga River) had the greatest number of eggs per individual female. The high frequency of external abnormalities observed on brown bullhead from the contaminated sites did not appear to have a detrimental influence on fecundity. These results suggest that fecundity of the brown bullhead was not adversely affected in ecosystems altered by the presence of contaminated sediments. Increased fecundity of the brown bullhead from impacted rivers may be the result of reduced competition for an abundant invertebrate food source and limited predation by other fish species whose numbers are largely depleted in these degraded systems.

  9. Variable growth and longevity of yellow bullhead (Ameiurus natalis) in the Everglades of south Florida, USA

    USGS Publications Warehouse

    Murie, D.J.; Parkyn, D.C.; Loftus, W.F.; Nico, L.G.

    2009-01-01

    Yellow bullhead (Ictaluridae: Ameiurus natalis) is the most abundant ictalurid catfish in the Everglades of southern Florida, USA, and, as both prey and predator, is one of many essential components in the ecological-simulation models used in assessing restoration success in the Everglades. Little is known of its biology and life history in this southernmost portion of its native range; the present study provides the first estimates of age and growth from the Everglades. In total, 144 yellow bullheads of 97-312 mm total length (TL) were collected from canals and marshes of the Everglades between April 2000 and January 2001, and from October 2003 to February 2005. Fish were aged using cross-sections of pectoral spines and ranged from 1-12 years, with the maximum age almost twice that of any yellow bullhead previously reported. Yellow bullheads from south Florida grew relatively rapidly during their first 3 years, but after age 5 growth slowed and fish approached an asymptote of ???214 mm TL. Compared to other populations in the United States, yellow bullhead in the Everglades grew relatively slowly, were smaller at age overall, but survived to older ages. ?? 2009 Blackwell Verlag GmbH.

  10. Prevalence of Tumors in Brown Bullhead from Three Lakes in Southeastern Massachusetts, 2002

    USGS Publications Warehouse

    Baumann, Paul C.; LeBlanc, Denis R.; Blazer, Vicki; Meier, John R.; Hurley, Stephen T.; Kiryu, Yasu

    2008-01-01

    The Massachusetts Military Reservation (MMR) has been a military base on western Cape Cod since the early 1900s. Contaminated surface water and ground water from the MMR have discharged into several kettle lakes on or near the base. To discover whether the prevalences of tumors and other lesions in brown bullhead (Ameiurus nebulosus) in these lakes, particularly Ashumet Pond, were elevated above normal, the U.S. Geological Survey (USGS), assisted by the U.S. Environmental Protection Agency (USEPA) and the Massachusetts Division of Fisheries and Wildlife (MADFW), conducted a study in 2002 of brown bullhead in Ashumet Pond and in two reference lakes, Santuit Pond (on Cape Cod) and Great Herring Pond (on the mainland of Massachusetts). Brown bullhead from Great Herring Pond had few external raised lesions (2.8 percent), a low prevalence of liver neoplasms (5 percent), and little genetic damage to their red blood cell nuclei. Brown bullhead from Ashumet Pond had a high prevalence of raised lesions (62.1 percent), which included histopathologically verified papillomas and squamous carcinoma; an elevated incidence of liver neoplasms (16.7 percent); and an elevated level of genetic damage to their red blood cell nuclei. Because red blood cells in fish have a lifespan of about 100 days, these results indicate an ongoing exposure to genotoxins in Ashumet Pond. Brown bullhead from Santuit Pond also had elevated prevalences of raised lesions (48.3 percent) and liver neoplasms (15 percent), although the prevalences of large and multiple lesions were significantly lower than those in fish from Ashumet Pond. These differences may indicate differing causes of pathology in the two lakes. The high prevalence of melanistic lesions on brown bullhead from Ashumet Pond, combined with the tumor pathology and genetic damage, implicates chemical carcinogens as one of the causal factors in that lake.

  11. Diagnostic criteria for proliferative hepatic lesions in brown bullhead Ameiurus nebulosus

    USGS Publications Warehouse

    Blazer, V.S.; Fournie, J.W.; Wolf, J.C.; Wolfe, M.J.

    2006-01-01

    Brown bullhead Ameiurus nebulosus is used as indicator species for contaminant effects at areas of concern (AOC) in the Great Lakes and other areas. One of the beneficial use impairments at numerous AOC is 'fish tumors and other deformities'. An impairment occurs when the prevalence of fish tumors and other deformities exceeds those at unimpacted or control sites or when survey data confirm the presence of neoplastic or preneoplastic liver lesions in bullhead or white sucker Catostomus commersonii. Numerous surveys have been conducted over the years assessing neoplasia in these fishes, both liver and skin tumors. However, a major problem in comparing the results has been a lack of consistent criteria for evaluating histological changes in bullhead livers. As individual AOC develop and implement remedial action plans, realistic and attainable delisting targets need to be specified. For this to occur and be consistent from site to site there must be standardization of the criteria being used to evaluate specific impairments. In this report, specific diagnostic criteria are provided for both non-neoplastic and neoplastic proliferative hepatocellular and biliary lesions. These criteria should assist fish pathologists in describing and categorizing proliferative liver lesions from brown bullhead. ?? Inter-Research 2006.

  12. SYNCHRONOUS FLUOROMETRIC MEASUREMENT OF METABOLITES OF POLYCYCLIC AROMATIC HYDROCARBONS IN THE BILE OF BROWN BULLHEAD

    EPA Science Inventory

    A synchronous fluorescent spectroscopy (SFS) method was developed to measure pyrene-type metabolites in the bile of brown bullhead (Ameiurus nebulosus) and to estimate the exposure of fish to PAHs in four Lake Erie tributaries collected in the spring and fall of 1990 and 1991. Fo...

  13. Glucagon binding to hepatocytes isolated from two teleost fishes, the American eel and the brown bullhead.

    PubMed

    Navarro, I; Moon, T W

    1994-02-01

    We have characterized the specific binding of glucagon in hepatocytes isolated from two teleost species, the American eel (Anguilla rostrata) and the brown bullhead (Ictalurus nebulosus). Specific glucagon binding was 9.3 and 10.7% in bullhead and eel hepatocytes respectively, after a 2-h incubation at 12 degrees C. Curvilinear Scatchard plots suggest the presence of two classes of binding sites with apparent dissociation constants (Kd) of 1.97 nM (high affinity) and 17.3 nM (low affinity) for bullhead and 2.68 and 22.9 nM for eel cells. The number of high-affinity binding sites per cell was significantly higher in the eel (10,413) than in the bullhead (3811). The number of high-affinity insulin-binding sites was approximately two times higher than that for glucagon in bullheads and the opposite in the eel hepatocytes. In competition experiments, insulin did not displace 125I-labelled glucagon binding in the hepatocytes of either species, while glucagon-like peptide-1(7-37) (GLP-1) displaced glucagon but only at high concentrations, suggesting separate glucagon- and GLP-1-binding sites. The rate of dissociation of hepatocyte-bound 125I-labelled glucagon was similar for both species. Preincubation of hepatocytes in 100 nM glucagon decreased the number of high-affinity glucagon-binding sites by approximately 55% in both species, while the Kd values remained unchanged. Glucagon bound to the cell surface is internalized by fish hepatocytes. These properties indicate that the glucagon binding to hepatocytes of these two teleost species is similar to that reported for mammalian hepatocytes.

  14. Tumor prevalence and biomarkers of genotoxicity in brown bullhead (Ameiurus nebulosus) in Chesapeake Bay tributaries

    USGS Publications Warehouse

    Pinkney, Alfred E.; Harshbarger, John C.; Karouna-Renier, Natalie K.; Jenko, Kathryn; Balk, Lennart; Skarphéðinsdóttir, Halldora; Liewenborg, Birgitta; Rutter, Michael A.

    2011-01-01

    We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between tumor prevalence and polynuclear aromatic hydrocarbons (PAHs) and alkylating agents; and 3) statistically analyze Chesapeake Bay bullhead tumor data from 1992 through 2008. All four South River collections exhibited high skin tumor prevalence (19% to 58%), whereas skin tumor prevalence was 2%, 10%, and 52% in the three Severn collections; 0% and 2% in the Choptank collections; and 5.6% in the Rhode collection. Liver tumor prevalence was 0% to 6% in all but one South River collection (20%) and 0% to 6% in the three other rivers. In a subset of samples, PAH-like biliary metabolites and 32P-DNA adducts were used as biomarkers of exposure and response to polycyclic aromatic compounds (PACs). Adducts from alkylating agents were detected as O6-methyl-2'-deoxyguanosine (O6Me-dG) and O6-ethyl-2'-deoxyguanosine (O6Et-dG) modified DNA. Bullheads from the contaminated Anacostia River were used as a positive control for DNA adducts. 32P-DNA adduct concentrations were significantly higher in Anacostia bullhead livers compared with the other rivers. We identified alkyl DNA adducts in bullhead livers from the South and Anacostia, but not the Choptank. Neither the PAH-like bile metabolite data, sediment PAH data, nor the DNA adduct data suggest an association between liver or skin tumor prevalence and exposure to PACs or alkylating agents in the South, Choptank, Severn, or Rhode rivers. Logistic regression analysis of the Chesapeake Bay database revealed that sex and length were significant covariates for liver tumors and length was a significant covariate for skin tumors.

  15. Tumor prevalence and biomarkers of genotoxicity in brown bullhead (Ameiurus nebulosus) in Chesapeake Bay tributaries.

    PubMed

    Pinkney, Alfred E; Harshbarger, John C; Karouna-Renier, Natalie K; Jenko, Kathryn; Balk, Lennart; Skarphéðinsdóttir, Halldóra; Liewenborg, Birgitta; Rutter, Michael A

    2011-12-01

    We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between tumor prevalence and polynuclear aromatic hydrocarbons (PAHs) and alkylating agents; and 3) statistically analyze Chesapeake Bay bullhead tumor data from 1992 through 2008. All four South River collections exhibited high skin tumor prevalence (19% to 58%), whereas skin tumor prevalence was 2%, 10%, and 52% in the three Severn collections; 0% and 2% in the Choptank collections; and 5.6% in the Rhode collection. Liver tumor prevalence was 0% to 6% in all but one South River collection (20%) and 0% to 6% in the three other rivers. In a subset of samples, PAH-like biliary metabolites and (32)P-DNA adducts were used as biomarkers of exposure and response to polycyclic aromatic compounds (PACs). Adducts from alkylating agents were detected as O6-methyl-2'-deoxyguanosine (O6Me-dG) and O6-ethyl-2'-deoxyguanosine (O6Et-dG) modified DNA. Bullheads from the contaminated Anacostia River were used as a positive control for DNA adducts. (32)P-DNA adduct concentrations were significantly higher in Anacostia bullhead livers compared with the other rivers. We identified alkyl DNA adducts in bullhead livers from the South and Anacostia, but not the Choptank. Neither the PAH-like bile metabolite data, sediment PAH data, nor the DNA adduct data suggest an association between liver or skin tumor prevalence and exposure to PACs or alkylating agents in the South, Choptank, Severn, or Rhode rivers. Logistic regression analysis of the Chesapeake Bay database revealed that sex and length were significant covariates for liver tumors and length was a significant covariate for skin tumors.

  16. Biomarkers of exposure of brown bullheads (Ameiurus nebulosus) to contaminants in the lower Great Lakes, North America

    SciTech Connect

    Arcand-Hoy, L.D.; Metcalfe, C.D.

    1999-04-01

    Brown bullheads (Ameiurus nebulosus) from three contaminated sites (Detroit River, Hamilton Harbour, and Black River) and two relatively clean reference sites (Old Woman Creek and Bay of Quinte) in the lower Great Lakes were monitored for several biomarkers of exposure to PAHs. Bullheads from the contaminated sites had elevated hepatosomatic indices, increased ethoxyresorufin-O-deethylase (EROD) activity, decreased hepatic retinoid stores, and a greater incidence of hepatic neoplasms. Fluorescent aromatic compounds (FACs) in the bile were also elevated in bullheads from the Black River and Hamilton Harbour in comparison to fish from reference sites. A correlation was found between reduction of hepatic retinoid stores and induction of hepatic EROD activity in bullheads. Principal component analysis of biomarker data demonstrated that biomarker patterns in Detroit River bullheads were different from those of Black River and Hamilton Harbour bullheads. Biomarkers in fish are useful monitoring tools for detecting contamination of the aquatic environment, but interpretation of results is limited by within- and between-site variability in the responses, some of which may be explained by mobility of the fish. In contaminated areas, bile fluorescent aromatic compounds appear to be the best indicator of recent exposure to polynuclear aromatic hydrocarbons, whereas responses to other biochemical biomarkers appear to be over a longer time period.

  17. DNA damage and external lesions in brown bullheads (Ameiurus nebulosus) from contaminated habitats

    USGS Publications Warehouse

    Yang, X.; Meier, J.; Chang, L.; Rowan, M.; Baumann, P.C.

    2006-01-01

    The Comet assay was used to compare levels of DNA damage in brown bullheads (Ameiurus nebulosus) collected from three known contaminated locations, the Cuyahoga River (OH, USA), Ashtabula River (OH, USA; both tributaries to Lake Erie, USA), and Ashumet Pond (Cape Cod, MA, USA), with brown bullheads collected from three paired reference sites, Old Woman Creek (OH, USA), Conneaut River (OH, USA; both tributaries to Lake Erie), and Great Herring Pond (mainland MA, USA), respectively. Blood was sampled from each fish, and the Comet assay was conducted on erythrocytes. The assay results demonstrate that fish from the three contaminated sites each suffered higher DNA damage compared with fish from their respective reference sites. The results also show that the genetic damage was associated with the occurrence of external lesions and deformities in fish. The Comet assay is sufficiently sensitive to detect exposure of natural fish populations to environmental levels of genotoxic contaminants. ?? 2006 SETAC.

  18. 75 FR 19246 - Safety Zone; Desert Storm, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Desert Storm, Lake Havasu, AZ AGENCY: Coast... Havasu City, Arizona in support of the Desert Storm Exhibition Run. This temporary safety zone is... Purpose The Lake Racer LLC is sponsoring the Desert Storm Charity Poker Run and Exhibition Run, which...

  19. Postglacial colonization of Northern Europe by distinct phylogeographic lineages of the bullhead, Cottus gobio.

    PubMed

    Kontula, T; Väinölä, R

    2001-08-01

    Three major phylogeographic lineages of the cottid fish Cottus gobio (bullhead) were identified in northern Europe from mitochondrial DNA sequences and allozyme data. The largely separate freshwater distributions of the lineages demonstrate distinct postglacial colonization histories. West of the Baltic Sea, Swedish lakes were invaded from the southwest (Germany). Another, eastern lineage has colonized the inland waters northeast and east of the Baltic, from refugia in northwest Russia; this lineage comprises a distinct subgroup found only from Estonia. The third lineage, found south and southeast of the Baltic, probably descended from rivers draining to the Black Sea from the north (e.g. Dnepr). In coastal waters of the Baltic Sea, and in near-coast inland waters, the lineages are now found intermixed in various combinations. The alternating fresh- and saltwater phases of the Baltic basin have variously enabled and disabled the use of coastal waters as colonization routes. Hypotheses on the chronology of dispersal and lineage mixing can be based on the distribution of the marker genes and the paleohydrographical record. The diversity of the Fennoscandian bullhead thus comprises anciently diverged (probably mid-Pleistocene) refugial lineages that in their freshwater range constitute distinct evolutionarily significant units. The thorough mixing of the various genomic origins in and around the Baltic, however, refutes the controversial view of distinct species status for the western and eastern ('Cottus koshewnikowi') bullheads. The postglacial contact of the lineages has created new diversity that cannot be interpreted in a conventional hierarchical framework of taxonomic or conservation units.

  20. Tumor prevalence and biomarkers in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River watershed [poster

    USGS Publications Warehouse

    Mitchell, R.T.

    2000-01-01

    Associations between contaminant exposure and liver and skin tumor prevalence were evaluated in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River watershed. Thirty bullheads (>260 mm) were collected from (1) Quantico embayment, near a Superfund site which released organochlorine contaminants; (2) Neabsco Creek, a tributary with petroleum inputs from runoff and marinas; and (3) Anacostia River (spring and fall), an urban tributary designated as a Chesapeake Bay Region of Concern, contaminated with PCBs, PAHs, and organochlorine pesticides. Fish were collected from the Tuckahoe River, as a reference. Cytochrome P450 activity, bile PAH metabolites, and muscle organochlorine pesticide/PCB concentrations were measured in randomly-selected individuals and sediment contaminants were analyzed. We found statistically significant differences in liver tumor prevalences: Anacostia (spring)-50%, Anacostia (fall)-60%, Neabsco-17%, Quantico-7%, Tuckahoe-10%. Skin tumor prevalences were significantly different: Anacostia (spring)-37%, Anacostia (fall)-10%, Neabsco-3%, Quantico-3%, Tuckahoe-0%. Tumor prevalence in Anacostia bullheads warrants concern and was similar to those at highly contaminated sites in the Great Lakes. There was evidence of higher PAH exposure in Anacostia fish but a cause-effect linkage cannot be established. Fish tumor surveys, with histopathological examination of internal and external organs, are recommended for monitoring the status of Regions of Concern.

  1. Temperament in bullheads: do laboratory and field explorative behaviour variables correlate?

    NASA Astrophysics Data System (ADS)

    Kobler, Alexander; Engelen, Brecht; Knaepkens, Guy; Eens, Marcel

    2009-10-01

    The relevance of temperament traits for life history strategy or productivity is increasingly acknowledged. Temperament traits are often either observed in captivity or in the wild, but studies combining both observations are very rare. We examine whether exploratory behaviour in the bullhead ( Cottus perifretum), assayed under laboratory conditions, predicts this behaviour under field conditions. Forty-three PIT-tagged individuals were first assayed for exploration of a novel environment in the aquarium and then released into an unfamiliar stream stretch, where they were later relocated using a mobile antenna. Explorative behaviour assayed in the laboratory was significantly positively related to the exploration in the field, thus predicting distance moved in the field release. Both in the laboratory and in the field, explorative behaviour was not related to individual body length. When bullheads that did not leave the refuge in the aquarium (laboratory assay) and, therefore, did not explore the new environment were excluded from the analysis, the correlation between laboratory and field explorative behaviour variables became weaker. However, overall, our results illustrate that exploration rate of bullheads in isolated single-individual experiments can be used to predict this behaviour in the natural ecosystem.

  2. Movements of brown bullheads in Presque Isle Bay, Lake Erie, Pennsylvania

    USGS Publications Warehouse

    Millard, M.J.; Smith, D.R.; Obert, E.; Grazio, J.; Bartron, M.L.; Wellington, C.; Grise, S.; Rafferty, S.; Wellington, R.; Julian, S.

    2009-01-01

    Presque Isle Bay, Lake Erie, was listed as an Area of Concern (AOC) by the International Joint Commission in part because of the high incidence of external tumor in brown bullheads. Verifying the source of the possible contaminant exposure is critical to addressing the AOC designation. We used telemetry tracking (n = 49 fish) to test the hypothesis that adult bullheads captured within the bay during spawning season do not exit the bay during the post-spawning summer and fall months. We analyzed genetic variation at 15 microsatellite loci for 112 adult fish from 5 locations, 4 inside the bay and 1 outside, in order to test for possible differences. Data from fixed-station receivers suggested fish did not leave Presque Isle Bay during the study period. Predicted locations outside Presque Isle Bay were only 0.1% of all predicted locations and were below the 0.2% error rate based on known manual relocations. However, there was evidence for movement within Presque Isle Bay. Most movement was between Misery Bay or Lagoons and the open bay area. Whereas telemetry results showed tendency for adult site fidelity, genetic results showed no differences among locations, indicating that there is a single panmictic population. Our telemetry data suggest that brown bullheads are likely a useful indicator species for environmental conditions in Presque Isle Bay, since adults likely are retained in the system.

  3. Tumor frequencies in walleye (Stizostedion vitreum) and brown bullhead (Ictalurus nebulosus) and sediment contaminants in tributaries of the Laurentian Great Lakes

    USGS Publications Warehouse

    Baumann, Paul C.; Mac, Michael J.; Smith, Stephen B.; Harshbarger, John C.

    1991-01-01

    To better characterize neoplasm epizootics in the Great Lakes basin and their association with families of contaminants, we sampled five locations: the Fox and Menominee rivers, Lake Michigan; Munuscong Lake, St. Mary's River; and the Black and Cuyahoga rivers, Lake Erie. Frequencies of external and liver tumors were determined for brown bullhead (Ictalurus nebulosus) from all locations except the Black River and for walleye (Stizostedion vitreum) from the Lake Michigan and St. Mary's River sites. Sediment samples were analyzed for metals, polychlorinated aromatics, and polynuclear aromatic hydrocarbons (PAH). Liver neoplasms occurred in brown bullhead from the Cuyahoga River and Munuscong Lake; brown bullhead captured from Munuscong Lake were older than those collected from the other locations. Brown bullhead from these same two rivers had elevated hepatosomatic indexes. No liver neoplasms were found in brown bullhead from the Fox and Menominee rivers, although polychlorinated aromatics were highest in both Fox River sediment and Fox and Menominee brown bullhead, and arsenic was highest in Menominee River sediment and fish. Liver neoplasms in brown bullhead from the Cuyahoga River fit the prevailing hypothesis that elevated PAH in sediment can induce cancer in wild fish. The cause of the liver neoplasms in Munuscong Lake brown bullhead is undetermined.

  4. Mortality and pathology in brown bullheads Amieurus nebulosus associated with a spontaneous Edwardsiella ictaluri outbreak under tank culture conditions

    USGS Publications Warehouse

    Iwanowicz, L.R.; Griffin, A.R.; Cartwright, Deborah D.; Blazer, V.S.

    2006-01-01

    Brown bullheads Amieurus nebulosus (family Ictaluridae) are commonly used as a sentinel of environmental contamination. These fish are not generally cultured under laboratory conditions and little is known about their disease susceptibility. Here we report an outbreak of disease due to Edwardsiella ictaluri in a laboratory population of tank-reared, wild-caught brown bullheads. The isolate was positively identified as E. ictaluri using standard bacteriological substrate utilization tests and a monoclonal antibody specific for this bacterium. This pathogen causes a significant disease in channel catfish Ictalurus punctatus and is associated with disease in other ictalurid and non-ictalurid fishes. It appears that E. ictaluri is also a significant pathogen in brown bullheads and produces clinical signs and lesions similar but not identical to those observed in channel catfish. Since commercial sources of bullheads for laboratory tank studies are not available, precautions should be taken to prevent potential E. ictaluri disease outbreaks from wild-caught bullheads intended for laboratory research. ?? Inter-Research 2006.

  5. Induction of Ovulation by Hormone Treatment in Ussurian Bullhead Leiocassis ussuriensis

    PubMed Central

    Lim, Sang Gu; Kim, Young Soo; Han, Hyung Kyun; Kim, Kwang Suk; Kim, Dae Jung; Kang, Eon Jong; Son, Sang Gyu; Kim, Eung Oh

    2012-01-01

    The effects of ovulation induction in ussurian bullhead, Leiocassis ussuriensis, were investigated by treating ussurian bullhead with hCG, LHRHa, GnRHa, ovaprim, and pimozide. hCG was injected to ussurian bullhead at 0.75% NaCl, 5,000, 10,000, 20,000, and 30,000 IU, respectively. The ovulation inducement rates were 100% in 20,000 and 30,000 IU. Fertilization rates were 82.7% and 79.8%. Hatching rates were 59.4% and 57.2%. Ovulation time was between 16-19 hr The concentrations of LHRHa injected were 0.75 NaCl, 50, 100, 200, 300, and 300 g/kg. The ovulation inducement rates were 100% in 300 and 400 µg/kg. Fertilization and hatching rates were 84.9% and 68.4% at 200 µg/kg. The times to ovulation were between 23 hr and 34 hr. Ovaprim of 0.75% NaCl, 1.0, 1.5, 2.0, 2.5 and 3.0 ml/kg were injected to the abdominal cavity. The ovulation inducement rate was highest at 2.0 and 3.0 ml/kg to 92% and ovulation time was between 27-38 hr. LHRHa concentrations of 0.75% NaCl, 50, 100, 200, 300 and 400 µg were injected with pimozide (1,000 µg). Ovulation inducement rate was 100% from 200 to 400 IU with pimozide. Ovulation time was 22-36 h. Fertilization and hatching rates were 88.9% and 70.4% in 200 µg/kg with pimozide. PMID:25949100

  6. 6. Frisco Street streetscape, looking southeast. AZ167 and AZ168 (Archie ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Frisco Street streetscape, looking southeast. AZ-167 and AZ-168 (Archie Morrison Rental Houses) at left. - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  7. Aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus

    USGS Publications Warehouse

    Iwanowicz, L.R.; Blazer, V.S.; McCormick, S.D.; Van Veld, P.A.; Ottinger, C.A.

    2009-01-01

    The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were exposed to the PCB mixture, Aroclor 1248, via intraperitoneal injection and the effects on immune function, plasma hormones and disease resistance were evaluated. Exposure to this mixture led to a decrease in bactericidal activity and circulating antibodies to Edwardsiella ictaluri present from a previous exposure to this pathogen. A subsequent E. ictaluri disease challenge led to significantly higher mortality in A1248 treated fish compared to vehicle-control fish. The mitogenic response to the T-cell mitogen, phytohemaglutinin-P, was increased compared to vehicle-control fish. The steroid hormone, cortisol, and the thyroid hormone, T3, were also significantly lower in A1248 exposed fish. In summary, we have validated a number of functional immune assays for application in brown bullhead immunotoxicity studies. Additionally, we have demonstrated that the PCB mixture (A1248) modulates both immune function and endocrine physiology in brown bullhead. Such data may compliment the interpretation of data yielded from applied field studies conducted in PCB contaminated aquatic ecosystems.

  8. HISTORICAL MONITORING OF BIOMARKERS OF PAH EXPOSURE OF BROWN BULLHEAD IN THE REMEDIATED BLACK RIVER AND THE CUYAHOGA RIVER, OHIO

    EPA Science Inventory

    Biomarkers of exposure to chemical contamination were measured in brown bullhead from a heavily PAH contaminated section of the Black River, Ohio, during and immediately after remedial sediment dredging in 1990-1991, and in follow-up visits in 1993 and 1998. Biomarker levels of ...

  9. Temporal and spatial patterns in tumour prevalence in brown bullhead Ameiurus nebulosus (Lesueur) in the tidal Potomac River watershed (USA).

    PubMed

    Pinkney, A E; Harshbarger, J C; Rutter, M A

    2014-10-01

    For two decades, fish tumour surveys have been used to monitor habitat quality in the Chesapeake Bay (USA) watershed. Tributaries with sediments contaminated with polynuclear aromatic hydrocarbons (PAHs), known to cause liver neoplasia, were frequently targeted. Here, we compare surveys in brown bullhead Ameiurus nebulosus conducted in 2009-2011 in the tidal Potomac River watershed (including the Anacostia River) with previous surveys. Using logistic regression, we identified length and sex as covariates for liver and skin tumours. We reported a statistically significant decrease in liver tumour probabilities for standardized 280 mm Anacostia bullheads between the 1996 and 2001 samplings (merged collections: female-77.5%, male-43.0%) and 2009-2011 (female-42.2%, male-13.6%). However, liver tumour prevalence in bullheads from the Anacostia, Potomac River (Washington, DC) and Piscataway Creek (17 km downriver) was significantly higher than that for Chesapeake Bay watershed reference locations. The causes of skin tumours in bullheads are uncertain, requiring further research. The similar liver tumour prevalence in these three locations suggests that the problem is regional rather than restricted to the Anacostia. To monitor habitat quality and the success of pollution control actions, we recommend conducting tumour surveys on a 5-year cycle coordinated with sediment chemistry analyses. PMID:24974857

  10. Metabolism of benzo[a]pyrene and persistence of DNA adducts in the brown bullhead (Ictalurus nebulosus).

    PubMed

    Sikka, H C; Steward, A R; Kandaswami, C; Rutkowski, J P; Zaleski, J; Kumar, S; Earley, K; Gupta, R C

    1991-01-01

    1. The in vitro metabolism of [3H]benzo[a]pyrene (BP) and [14C]benzo[a]pyrene-7,8-dihydrodiol (BP-7,8-diol) by liver of brown bullhead (Ictalurus nebulosus) was characterized, as was the formation and persistence of BP-DNA adducts in vivo. 2. Compared to rat liver microsomes, bullhead liver microsomes produced relatively larger amounts of BP-7,8-diol (predominantly the [-] enantiomer) and smaller amounts of of BP-7,8-diol (predominantly the [-] enantiomer) and smaller amounts of BP-4,5-diol. 3. BP phase I metabolites were efficiently converted by freshly isolated bullhead hepatocytes to conjugates, predominantly glucuronides. 4. BP-7,8-diol was metabolized by hepatocytes 4-fold more rapidly than was BP and was converted to approximately equal amounts of glucuronides, glutathione conjugates and sulfates. 5. BP-DNA adducts formed in bullhead liver with a lag time of several days and maximum adduct formation at 25-30 days. The major adduct was anti-BPDE-deoxyguanosine.

  11. 76 FR 23787 - Voluntary Termination of Foreign-Trade Subzone 75D, STMicroelectronics, Inc., Phoenix, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ..., 61 FR 1322, 01/19/ 1996); Whereas, the City of Phoenix has advised that zone procedures are no longer...., Phoenix, AZ Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as amended (19 U... issued a grant of authority to the City of Phoenix (grantee of FTZ 75) authorizing the establishment...

  12. Mitochondrial DNA diversity of brown bullhead from contaminated and relatively pristine sites in the Great Lakes

    SciTech Connect

    Murdoch, M.H.; Hebert, P.D.N. . Dept. of Zoology)

    1994-08-01

    Brown bullhead were sampled from contaminated and relatively pristine sites to determine whether there was any association between genetic diversity and site contamination. Nine sites were sampled in the lower Great Lakes: five from Areas of Concern (identified by the International Joint Commission as having significant environmental degradation) and four from relatively clean areas of similar habitat type. Genetic variation was surveyed in the mitochondrial genome using restriction fragment length polymorphisms. Sixteen restriction enzymes were used to identify 42 distinct mitochondrial DNA haplotypes among 163 fish. Eight pairwise comparisons of populations at contaminated vs. clean sites showed that genetic diversity estimates were always lower in populations from contaminated sites. The most parsimonious explanation is that reduced diversity is a result of stochastic reductions in population size that have culled much of the genetic diversity from populations. Although contaminated sites support large populations of brown bullhead, historical environmental degradation at these sites may have reduced population size in the past, resulting in reduced present-day genetic diversity.

  13. Chlordane, DDT, PCB's, and other selected organic compounds in Asiatic clams and yellow bullhead in the Potomac River Basin, 1992

    USGS Publications Warehouse

    Zappia, Humbert

    1996-01-01

    Chlordane, DDT (dichlor-diphenyl-trichloroethane), and PCB's (polychlorinated biphenyls) were the most widespread organic contaminants detected during a 1992 survey of aquatic biological tissues in the Potomac River Basin. On the basis of existing U.S. Food and Drug Administration criteria, no new threats to human health were discovered, although chlordane concentrations may pose a threat to fish-eating wildlife. Chlordane exceeded the National Academy of Science and National Academy of Engineering recommended maximum concentration for the protection of fish-eating wildlife at two sites. The survey, conducted by the U.S. Geological Survey's National Water-Quality Assessment Program, sampled Asiatic clams (Corbicula fluminea) and yellow bullhead (Ameiurus natalis) at 16 sites to determine the occurrence and distribution of 29 hydrophobic organic compounds. Thirteen of these organic compounds were detected in the survey. Sites with the greatest number of compounds detected include the Potomac River near Alexandria, Va., with 6 compounds detected in Asiatic clam tissue, and Accotink Creek near Annandale, Va., with 11 compounds in yellow bullhead tissue. Chlordane was detected at six sites, with maximum concentrations of 31.1 ?g/kg (micrograms per kilograms) in Asiatic clam tissue and 127 ?g/kg in yellow bullhead whole-fish tissue. DDT was detected at five sites, with maximum concentrations of 12.9 ?g/kg in Asiatic clam tissue and 7.6 ?g/kg in yellow bullhead whole-fish tissue. PCB's were detected at nine sites, with maximum concentrations of 162 ?g/kg in Asiatic clam tissue and 146 mg/ kg in yellow bullhead whole-fish tissue.

  14. Az-Tech Medicine.

    ERIC Educational Resources Information Center

    Nicholson, Rob

    2000-01-01

    Created in 1552 as a gift for Spain's king, the Badianus Manuscript is a repository of Aztec traditional medicinal knowledge and contains the earliest surviving illustrations of New World plants. At the College of Santa Cruz (Mexico City) for Aztec nobility, an Aztec healer who became the college physician compiled plant descriptions and medicinal…

  15. Synchronous fluorometric measurement of metabolites of polycyclic aromatic hydrocarbons in the bile of brown bullhead

    SciTech Connect

    Lin, E.L.C.; Cormier, S.M. . Environmental Monitoring Systems Lab.); Racine, R.N.

    1994-05-01

    A synchronous fluorescent spectroscopy (SFS) method was developed to measure pyrene-type metabolites in the bile of brown bullhead (Ameiurus nebulosus) and to estimate the exposure of fish to PAHs in four Lake Erie tributaries collected in the spring and fall of 1990 and 1991. For comparison, fish biliary benzo[a]pyrene (B[a]P) metabolites were also measured by HPLC/fluorescent detection (HPLC/F). Both methods showed that concentrations of biliary PAH metabolites of fish collected in polluted rivers were significantly higher than those collected from reference rivers. Concentrations biliary metabolites of fish caught in the Black River were five to 20 times greater than those collected in Old Woman Creek by SFS and three to five times greater by HPLC/F. Fish from the Cuyahoga River had four to 24 times more biliary PAH metabolites than fish from Old Woman Creek, measured by SFS, and five to 10 times more, measured by HPLC/F. Brown bullhead from the Toussaint River had fewer PAH metabolites than fish from Old Woman Creek. Correlation analyses of the two sets of data obtained by SFS and HPLC/F showed significance by both Pearson's sample correlation and Spearman's rank correlation. This study indicates that pyrene-type metabolites determined by SFS can be used to estimate B[a]P-type metabolites in fish bile. SFS appears to be a highly sensitive method for detecting PAH metabolites and, because of its simplicity, a cost-efficient method for screening large numbers of samples for exposure to PAHs in fish.

  16. Decline in liver neoplasms in wild brown bullhead catfish after coking plant closes and environmental PAHs plummet

    SciTech Connect

    Baumann, P.C.; Harshbarger, J.C.

    1995-02-01

    Polycyclic aromatic hydrocarbons (PAHs) in both sediment and brown bullhead catfish tissues from the Black River in Lorain County, Ohio, declined by 65% and 93%, respectively, between 1980 and 1982. Sediment PAHs declined an additional 99% by 1987, coincident with the closure of a coking facility in 1983. Contemporaneously, liver cancer in 3- to 4-year-old brown bullheads declined to about one-quarter the 1982 frequency (10% versus 39%) by 1987, while the percentage of livers without any proliferative lesions doubled (42% versus 20%). These changes were significant within age group. Our data affirm a cause-and-effect relationship between PAH exposure and liver cancer in wild fish. The data also support the efficacy of natural, unassisted remediation once the source of the pollution is eliminated. 21 refs., 4 tabs.

  17. Decline in liver neoplasms in wild brown bullhead catfish after coking plant closes and environmental PAHs plummet.

    PubMed

    Baumann, P C; Harshbarger, J C

    1995-02-01

    Polycyclic aromatic hydrocarbons (PAHs) in both sediment and brown bullhead catfish tissues from the Black River in Lorain County, Ohio, declined by 65% and 93%, respectively, between 1980 and 1982. Sediment PAHs declined an additional 99% by 1987, coincident with the closure of a coking facility in 1983. Contemporaneously, liver cancer in 3- to 4-year-old brown bullheads declined to about one-quarter the 1982 frequency (10% versus 39%) by 1987, while the percentage of livers without any proliferative lesions doubled (42% versus 20%). These changes were significant within age group. Our data affirm a cause-and-effect relationship between PAH exposure and liver cancer in wild fish. The data also support the efficacy of natural, unassisted remediation once the source of the pollution is eliminated.

  18. Tumor prevalence and biomarkers of exposure in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River, USA, watershed

    USGS Publications Warehouse

    Pinkney, A.E.; Harshbarger, J.C.; May, E.B.; Melancon, M.J.

    2001-01-01

    Associations between contaminant exposure and liver and skin tumor prevalence were evaluated in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River, USA, watershed. Thirty bullheads (>age 3) were collected from Quantico embayment near a Superfund site that released organochlorine contaminants; Neabsco Creek, a tributary with petroleum inputs from runoff and marinas; and Anacostia River (spring and fall), an urban tributary designated as a Chesapeake Bay region of concern, that was contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides. Fish were collected from the Tuckahoe River, as a reference. Cytochrome P450 activity, bile PAH metabolites, and muscle organochlorine pesticide and PCB concentrations were measured in randomly selected individuals and sediment contaminants were analyzed. We found statistically significant differences in liver tumor prevalences: Anacostia (spring), 50%, Anacostia (fall), 60%, Neabsco, 17%, Quantico, 7%, and Tuckahoe, 10%. Skin tumor prevalences were significantly different: Anacostia (spring), 37%, Anacostia (fall), 10%, Neabsco, 3%, Quantico, 3%, and Tuckahoe, 0%. Tumor prevalences in Anacostia bullheads warrants concern and was similar to those as highly contaminated sites in the Great Lakes. Evidence was found of higher PAH exposure in Anacostia fish but a cause-effect linkage could not be established. Fish tumor surveys, with histopathologic examination of internal and external organs are recommended for monitoring the status of regions of concern.

  19. 75 FR 10552 - Noise Exposure Map Notice for Chandler Municipal Airport, Chandler, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ... Federal Aviation Administration Noise Exposure Map Notice for Chandler Municipal Airport, Chandler, AZ... Administration (FAA) announces its determination that the noise exposure maps submitted by City of Chandler, for Chandler Municipal Airport under the provisions of 49 U.S.C. 47501 et seq. (Aviation Safety and...

  20. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ... temporary safety zone upon the navigable waters of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix. This temporary safety zone is necessary to provide for the...

  1. Naturally occurring orocutaneous papillomas and carcinomas of brown bullheads (Ictalurus nebulosus) in New York State.

    PubMed

    Poulet, F M; Wolfe, M J; Spitsbergen, J M

    1994-01-01

    Ninety-four brown bullheads (Ictalurus nebulosus) with spontaneous orocutaneous neoplasms (papillomas and carcinomas) were studied grossly and by light microscopy. Of these 94 fish, 71 were selected from 505 fish examined macroscopically during field surveys and 23 were selected from those submitted for diagnostic study. Fish with neoplasms came from 17 locations throughout New York State: Buffalo River, Canaan Lake, Cazenovia Lake, Delta Lake, Fort Pond, Greenwood Lake, Hudson River, Lake George, Lake Tiorati, Lincoln Hall Pond. Lincoln Pond, Oneida Lake, Onondaga Lake, Rutland Pond, Salmon River, Silver Stream Reservoir and Swan Lake. The prevalence varied from 0 to 100%. Multiple neoplasms were more common (84/94, 89%) than solitary ones (10/94, 11%). In order of decreasing frequency, neoplasms arose on the head, especially the ventral aspect, the lower dental plate, the upper dental plate, the trunk, the barbels, the fins, the tongue, and the tail. Of the 38/94 brown bullheads (40%) with tumors in both upper and lower lips and dental plates, 24/38 (63%) had the tumors in opposition. Macroscopically, soft, pink or yellowish papillary masses protruded above the normal epithelial surfaces. Histologically, cutaneous and oral neoplasms originated from the morphologically similar Malpighian epithelial cells of the surface epithelia and from the outer cells of the enamel organ. Based on histopathologic criteria, cutaneous and oral neoplasms were considered the same disease in different anatomic locations. No apparent difference in biologic behavior was noted between cutaneous and oral neoplasms. The lesions apparently progressed from benign papilloma to locally invasive carcinoma (28/94, 30%). Neoplastic emboli were seen in one case, and no metastases were detected. There was no statistically significant difference between the susceptibility of males (20/57, 35%) and females (6/26, 23%) to carcinomas. An apparent correlation was noted between a higher frequency of

  2. Bioaccumulation of cesium-137 in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned nuclear reactor reservoir

    SciTech Connect

    McCreedy, C.D.; Glickman, L.T.; Jagoe, C.H.; Brisbin, I.L. Jr.

    1997-02-01

    Bioaccumulation of {sup 137}Cs was investigated in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned reactor reservoir, Pond B, Savannah River Site, Barnwell Co., South Carolina. The authors collected fish by trap-netting, and determined ages from pectoral spines. Muscle and other tissues were assayed for {sup 137}Cs by NaI-scintillation. Music {sup 137}Cs was unrelated to sex or mass of fish, but was related to age. Examination of least-squares means suggested that {sup 137}Cs in muscle increased up to about age 3, but did not increase with greater age. A modified Richards model showed equilibrium {sup 137}Cs concentration in muscle was acquired in approximately 2.4 years. Growth differed between sexes and the time to asymptotic body mass was longer than the time to attain equilibrium {sup 137}Cs concentration. Males attained an asymptotic mass of 577 g in approximately 6.3 years; females attained an asymptotic mass of 438 g in approximately 5.9 years. The cumulative {sup 137}Cs burden of the population was 4.9 {times} 10{sup 6} Bq, representing <0.001% of the {sup 137}Cs inventory of the reservoir. Concentration of {sup 137}Cs varied among tissues with gill and muscle the lowest and highest. Concentration of {sup 137}Cs in ovaries declined with increasing ovary mass. Until equilibrium is attained in these fish, {sup 137}Cs concentration is directly related to increasing age rather than size.

  3. Flow cytometric leukocyte population patterns in brown bullhead from three Ohio rivers

    SciTech Connect

    Torsella, T.A.; Neiheisel, T.; Cormier, S.M.; Bercz, P.

    1994-12-31

    Brown bullhead (A. nebulosus) were collected from three Ohio rivers: Old Woman Creek (OWC), classified as clean, Cuyahoga (CR) and Black Rivers (BR), documented as polluted. Each river was sampled in April and September 1993. Patterns of leukocyte distribution (prepared via density gradient) by GSH content and oxidative burst capacity, using fluorescent probes were determined by flow cytometry. Sample processing was in blind coded batches. Three principal classes of leukocytes were identified. Type A; large, very granular with high GSH reserves and marked capacity for oxidative burst. Type B were smaller, less granular, contained low GSH and negligible oxidative burst capacity. Type C were small, less granular, possessing intermediate GSH and peroxidative activity. ANOVA of the subset distributions and mean fluorescent intensities by sex, site and season, disclosed: Type C were significantly (p < 0.001) elevated in the spring OWC males, whereas type A dominated in the spring CR and spring BR males. No differences in Type A/Type C patterns were seen in the spring females. In the fall sampling, significant dominance (p < 0.001) of Type A was seen in both sexes of the OWC fish, the CR and BR fish showed a predominance of Type C. These may be explained by chemical stressors, affecting immune competence. Sex differences in the spring were attributed to hormonal (spawning) influences.

  4. Estimates of population genetic diversity in brown bullhead catfish by DNA fingerprinting

    SciTech Connect

    Roth, A.C.; Wessendarp, T.K.; Gordon, D.A.; Smith, M.K.; Lattier, D.L.; Hertzberg, V.; Leonard, A.

    1994-12-31

    Estimates of population genetic diversity may be a sensitive indicator of environmental impact, since limiting the effective breeding population by any means will result in loss of some variant genotypes, as has been demonstrated by allozyme analysis. DNA fingerprinting techniques are also coming into use for population analyses, and the authors chose to apply fingerprinting analysis three populations of brown bullhead catfish collected in Northern Ohio. DNA was isolated from the red blood cells of individual fish. Purified DNAs were digested with EcoR1 restriction enzyme; the digests were then sized on a 1% agarose gel, transferred to nylon membranes and probed with a radiolabeled M13 probe using the Westneat hybridization protocol (Southern blotting). This method effects fragments containing VNTR (variable number of tandem repeat) sequences complementary to the M13, which are highly variable among individual catfish. Hybridized bands were visualized by a Molecular Dynamics phosphorimager and recorded and analyzed with its proprietary Imagequant image analysis program, Excel and SAS. A total of 10 variable bands were identified and their presence or absence scored in each individual. These data were analyzed to determine between and within-population similarity indices as well as population heterozygosity and genetic diversity measures.

  5. Biliary PAH metabolites and the hepatosomatic index of brown bullheads from Lake Erie tributaries

    USGS Publications Warehouse

    Yang, X.; Baumann, P.C.

    2006-01-01

    In studies designed to investigate the environmental exposure of fish in Lake Erie tributaries, a benthic fish, the brown bullhead (Ameiurus nebulosus), was collected from the industrially contaminated Detroit River, Ottawa River, Black River, Cuyahoga River-harbor and -upstream, Ashtabula River, Buffalo River, and Niagara River, and the non-industrialized Old Woman Creek during 1997-2000. Biliary benzo[a]pyrene (B[a]P)- and naphthalene (NAPH)-type metabolites and the hepatosomatic index (HSI) were measured in fish and compared between different sites. Fish from all of the contaminated sites except Niagara River had significantly higher concentrations of both types of polycyclic aromatic hydrocarbon (PAH) metabolites than fish from the Old Woman Creek. Concentrations of PAH metabolites in bile of fish were positively associated with concentrations of PAHs in sediments, supporting the use of bile metabolites as a measure of PAH exposure. Relatively low concentrations of PAHs detected in fish bile and sediments of the Niagara River, which had undergone extensive remediation, suggested a lowered PAH exposure for fish at this site. No apparent trend was observed in HSI between the industrialized and non-industrialized sites. This study demonstrates that biliary PAH metabolites are an effective indicator of exposure of fish to PAHs. However, because factors other than contamination could also affect the liver size of wild fish, HSI alone may be not a reliable biomarker for assessing contaminant stress. ?? 2005 Elsevier Ltd. All rights reserved.

  6. The AzTEC Mathematics Project (AMP).

    ERIC Educational Resources Information Center

    Johnson, Gae R.

    The AzTEC Mathematics Project (AMP) is a statewide partnership among Arizona's Regents universities and state community colleges, partner school districts, and economic communities. AzTec is committed to preparing highly qualified K-12 mathematics and science teachers. AMP targeted Native American teachers and teachers of Native American students…

  7. Assessment of the fish tumor beneficial use impairment in brown bullhead (Ameiurus nebulosus) at selected Great Lakes Areas of Concern

    USGS Publications Warehouse

    Blazer, Vicki; Mazik, Patricia M.; Iwanowicz, Luke R.; Braham, Ryan P.; Hahn, Cassidy M.; Walsh, Heather L.; Sperry, Adam J.

    2014-01-01

    A total of 878 adult Brown Bullhead were collected at 11 sites within the Lake Erie and Lake Ontario drainages from 2011 to 2013. The sites included seven Areas of Concern (AOC; 670 individuals), one delisted AOC (50 individuals) and three non-AOC sites (158 individuals) used as reference sites. These fish were used to assess the “fish tumor or other deformities” beneficial use impairment. Fish were anesthetized, weighed, measured and any external abnormalities documented and removed. Abnormal orocutaneous and barbel tissue, as well as five to eight pieces of liver, were preserved for histopathological analyses. Otoliths were removed and used for age analyses. Visible external abnormalities included reddened (raised or eroded), melanistic areas and raised growths on lips, body surface, fins and barbels. Microscopically, these raised growths included papilloma, squamous cell carcinoma, osteoma and osteosarcoma. Proliferative lesions of the liver included bile duct hyperplasia, foci of cellular alteration, bile duct (cholangioma, cholangiocarcinoma) and hepatocellular (adenoma, hepatic cell carcinoma) neoplasia. The two reference sites (Long Point Inner Bay, Conneaut Creek), at which 30 or more bullhead were collected had a skin tumor prevalence of 10% or less and liver tumor prevalence of 4% or less. Presque Isle Bay, recently delisted, had a similar liver tumor prevalence (4%) and slightly higher prevalence (12%) of skin tumors. The prevalence of skin neoplasms was 15% or less at sites in the Black River, Cuyahoga River and Maumee AOCs, while more than 20% of the bullheads from the Rochester Embayment, Niagara River, Detroit River and Ashtabula River AOCs had skin tumors. The prevalence of liver tumors was greater than 4% at all AOC sites except the Old Channel site at the Cuyahoga River AOC, Wolf Creek within the Maumee AOC and the upper and lower sites within the Niagara River AOC.

  8. Long-term trends in liver neoplasms in brown bullhead in the Buffalo River, New York, USA.

    PubMed

    Lauren, Darrel J; Hinton, David; Law, Mac; Sorensen, Mary; Lyndall, Jennifer; Magar, Victor; Nielsen, Mark

    2010-08-01

    The Buffalo River area of concern (AOC) was assigned an impaired status for the fish tumors and other deformities beneficial use impairment category by the New York State Department of Environmental Protection in 1989. This was initially based on an inadequately documented brown bullhead (Ameiurus nebulosus) feeding study using river sediment extracts. The presence of liver tumors was subsequently supported by reports of a 19 to 27% prevalence in wild brown bullhead between 1983 and 1988 and a 4.8% prevalence in 1998. However, neither fish size (or age) nor sample locations were given, and histopathological definitions were inconsistent in these previous studies. Therefore, in 2008, we re-evaluated the prevalence of hepatocellular and chloangiocellular tumors (as well as other gross indicators of fish health) in brown bullhead averaging 25 cm in length collected from three reaches of the Buffalo River and recorded our collection sites by global positioning system. Among the 37 fish of appropriate size collected, only three exhibited liver tumors (8%). The tumors were evenly distributed within the three reaches, and only hepatocellular tumors were found. There were no differences in the prevalence of hepatic foci of alteration, body weight, length, or hepatosomatic index among the three reaches, but the conditions factor was significantly lower in fish from reach 2. Natural attenuation of water and sediment quality are the most likely causes for the decrease in liver tumors. The prevalence of liver tumors between 1998 and 2008 in the Buffalo River is similar to that found in recovery-stage AOCs and some Great Lakes reference areas. PMID:20821628

  9. Long-term trends in liver neoplasms in brown bullhead in the Buffalo River, New York, USA.

    PubMed

    Lauren, Darrel J; Hinton, David; Law, Mac; Sorensen, Mary; Lyndall, Jennifer; Magar, Victor; Nielsen, Mark

    2010-08-01

    The Buffalo River area of concern (AOC) was assigned an impaired status for the fish tumors and other deformities beneficial use impairment category by the New York State Department of Environmental Protection in 1989. This was initially based on an inadequately documented brown bullhead (Ameiurus nebulosus) feeding study using river sediment extracts. The presence of liver tumors was subsequently supported by reports of a 19 to 27% prevalence in wild brown bullhead between 1983 and 1988 and a 4.8% prevalence in 1998. However, neither fish size (or age) nor sample locations were given, and histopathological definitions were inconsistent in these previous studies. Therefore, in 2008, we re-evaluated the prevalence of hepatocellular and chloangiocellular tumors (as well as other gross indicators of fish health) in brown bullhead averaging 25 cm in length collected from three reaches of the Buffalo River and recorded our collection sites by global positioning system. Among the 37 fish of appropriate size collected, only three exhibited liver tumors (8%). The tumors were evenly distributed within the three reaches, and only hepatocellular tumors were found. There were no differences in the prevalence of hepatic foci of alteration, body weight, length, or hepatosomatic index among the three reaches, but the conditions factor was significantly lower in fish from reach 2. Natural attenuation of water and sediment quality are the most likely causes for the decrease in liver tumors. The prevalence of liver tumors between 1998 and 2008 in the Buffalo River is similar to that found in recovery-stage AOCs and some Great Lakes reference areas.

  10. Pigmented macrophage aggregates as a biomarker of oxidative damage in yellow bullhead catfish, Ameiurus natalis

    SciTech Connect

    McCreedy, C.D.; HoganEsch, H.; Turek, J.; Jagoe, C.H.

    1995-12-31

    Pigmented macrophage aggregates (PMs) occur when peroxidized lipids resulting from oxidative damage in tissues are scavenged by macrophages. Ionizing radiation causes oxidative damage, so the authors evaluated PMs as a biomarker in the pronephros of yellow bullheads (Ameiurus natalis) inhabiting Pond B, Savannah River Site, SC, a reservoir contaminated with low levels of {sup 137}Cs. ANOVA, ANCOVA, and stepwise regression were used to relate the mean number of PMs, per 0.15 mm{sup 2} of tissue section, to fish sex (females: N = 61; males: N = 84), age (1--6 yrs), body-condition, and muscle {sup 137}Cs concentration. Mean pronephric PMs differed by six and with fish muscle {sup 137}Cs concentration. Among males, PMs were positively correlated with fish age and {sup 137}Cs. In females, PMs were also correlated with fish age and {sup 137}Cs. ANCOVA, with age as covariate, affirmed that sex and muscle {sup 137}Cs were significantly associated with the mean number of pronephric PMs. Using stepwise regression, the interaction of age and {sup 137}Cs concentration was most strongly associated with pronephric PMs in males. Among females, the product of age, body-condition, and {sup 137}Cs concentration was most strongly associated with pronephric PMs. The positive relationships between the number of pronephric PMs and {sup 137}Cs concentration suggest that oxidative damage related to long-term exposure to low-level radiation is detectable in these fish. Secondarily, these results demonstrate the importance of considering covariates such as age and sex when evaluating effects of environmental contaminants.

  11. PCB accumulation in Hudson River pumpkinseed sunfish and bullhead: Influences of invertebrate prey

    SciTech Connect

    Feldman, R.S.

    1992-01-01

    Hudson River sediments are contaminated with PCBs, and these toxic compounds are also in the water and have accumulated in food chains. The relative importance of exposure by fish to contaminated water vs. contaminated prey was unknown. further, is was not known if difference in diet could influence fish PCB levels. Invertebrates and fish were sampled in different habitats to address these issues. Invertebrate communities differed in several ecological measures between two different plant beds, and among experimentally manipulated habitats in one plant bed. Communities often differed significantly in parameters such as total invertebrate density, densities of individual taxa, taxonomic richness and similarity, and size distributions; some taxa were also absent from one habitat but present in another. Total PCBs differed significantly for invertebrate communities between the two plant beds (9.4 vs. 31.4 [mu]g/g), and between some of the communities in the manipulated habitats (1.8 vs 5.3 [mu]g/g). These differences did not translate into difference in PCBs among fish that fed in the different habitats. However, bullhead had significantly higher levels than pumpkinseed (15.4 vs. 6.9 [mu]g/g). Yearling pumpkinseed that fed on Hudson River invertebrates had 5x the PCB levels of pumpkinseed exposed for the same period to the water but not to the prey, and 18x as much PCBs as fish unexposed to either Hudson River water or prey. Further, fish that fed on local prey had a higher proportion of high-Cl isomers than those exposed only to the contaminated water. Fish that fed in different habitats did not have different PCB levels. Thus, the role of diet needs further experimentation, but it is clear that local prey are the major route for PCB accumulation in yearling pumpkinseed.

  12. 20. Streetscape, South Coronado Boulevard, looking southwest Righttoleft, AZ198(Margaret B. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Streetscape, South Coronado Boulevard, looking southwest Right-to-left, AZ-198(Margaret B. Hill House), AZ-199 (Henry H. Hill House), AZ-200 (Henry H. Hill Rental House), AZ-201 (Otto Rosenthal House), AZ-202 (J. M. Stevens House), AZ-203 (L J. Dunagan House), AZ204 (C. W. Beck House), and AZ-205 (F. D. Connor House) face the street - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  13. Perfil de Franklin Chang- Díaz de Franklin Chang-Díaz

    NASA Video Gallery

    Franklin Chang-Díaz, el primer astronauta hispano de la NASA, habla sobre qué lo inspiró a trabajar con cohetes y convertirse en astronauta. Chang-Díaz alienta a los jóvenes para que sigan sus sueños.

  14. Recommendations to design environmental monitoring in the European bullhead, Cottus sp., based on reproductive cycle and immunomarker measurement.

    PubMed

    Bado-Nilles, Anne; Villeret, Mélanie; Geffard, Alain; Palluel, Olivier; Blanchard, Christophe; Le Rohic, Cindy; Besson, Sylvain; Porcher, Jean-Marc; Minier, Christophe; Sanchez, Wilfried

    2015-06-30

    European bullhead is a relevant fish species to assess adverse effects of environmental stress on wild fish. Nevertheless, their complex reproductive cycle is very different between sites and could interfere with many physiological processes. Thus, prior to use biomarker to statute on environmental quality of rivers, we wanted to characterize reproductive profile (spawn number, GSI, gonad development). The major results demonstrated that the two types of reproductive cycle shown were strongly correlated to water temperature variation. In a second time, even if innate immunomarkers are highly relevant on biomonitoring program, hormonal variation seems to impact severely their responses. Thus, the link between reproductive status and immune activity (leucocyte distribution, cellular mortality, respiratory burst, phagocytosis activity) must also be study. Nonetheless, in the present work, immune capacities seems to be more correlated with season and environmental factors than reproduction.

  15. Histopathological effects of sublethal exposure to phenol on two variously pre-stressed populations of bullhead (Cottus gobio L. )

    SciTech Connect

    Bucher, F.; Hofer, R. )

    1993-08-01

    Phenol is a common pollutant of aquatic ecosystems, into which it can be introduced by industrial waste water of different kinds (from refineries, chemical plants and paper mills), communal sewage, or decaying vegetation. In fish a very broad spectrum of toxic effects of phenol has been reported, ranging from disturbances in behavior to impairment of growth and reproduction or even serious organic damage. It has also been observed that previous exposure to phenol confers a certain degree of resistance. In the investigation reported here, the histopathological effects of phenol intoxication on bullhead (Cottus gobio) were studied, and the reactions of variously [open quotes]pre-exposed[close quotes] populations compared. 17 refs., 6 figs., 1 tab.

  16. Assessment of the "fish tumors or other deformities" beneficial use impairment in brown bullhead (Ameiurus nebulosus): II. Liver neoplasia

    USGS Publications Warehouse

    Blazer, V.S.; Rafferty, S.D.; Baumman, P.C.; Smith, S.B.; Obert, E.C.

    2009-01-01

    Liver pathology of fishes, including neoplastic and preneoplastic lesions, is widely used as an indicator of exposure to anthropogenic contaminants. By definition, the "fish tumor or other deformities" beneficial use impairment (BUI) at Great Lakes Areas of Concern (AOC) includes neoplastic and preneoplastic liver lesions in brown bullhead (Ameiurus nebulosus) or suckers. Unfortunately, adequate guidelines for defining neoplastic and preneoplastic liver lesions or determining rates at unimpacted control sites were not provided and different criteria have been used. In some cases, only neoplastic changes were used to calculate tumor prevalence, in some both neoplastic and preneoplastic changes and in some it is difficult to determine which changes were included. Using standardized criteria, the prevalence of liver neoplasia was compared at eight AOC during 1998-2000. The Cuyahoga River had the highest prevalence (25.0%), while the Maumee River had the lowest (3.9%). The Buffalo (4.8%), Detroit (5.9%), Ashtabula (6.8%), Niagara (7.5%) and Black (8.9%) rivers were intermediate, as was Presque Isle Bay (7.1%). From 2002 to 2007 the prevalence of liver neoplasia at Presque Isle Bay ranged from a low of 2.1% (2002) to a high of 12.0% (2007). Non-AOC sites, as potential reference sites, also were monitored during this time. By combining years and sites, the prevalence of liver neoplasia in bullhead (aged 2 to 12 years) at inland lakes was 0.7%, at bays/harbors was 1.6% and at tributary sites was 4.1%. This is the same trend (inland lakes < bays/harbors < tributaries < Presque Isle Bay) noted for orocutaneous neoplasms.

  17. Assessment of the "fish tumors or other deformities" beneficial use impairment in brown bullhead (Ameiurus nebulosus): I. Orocutaneous tumors

    USGS Publications Warehouse

    Blazer, V.S.; Rafferty, S.D.; Baumman, P.C.; Smith, S.B.; Obert, E.C.

    2009-01-01

    The "fish tumor or other deformities" beneficial use impairment (BUI) occurs at 9 of the 12 areas of concern (AOC) on Lake Erie. As point sources are mitigated and remediation occurs, AOC are faced with determining delisting criteria. The lack of standardized analyses for this BUI has confounded that process. For orocutaneous tumors, different criteria (presumptive tumors and/or abnormal barbels) and methodology (gross versus microscopic observations) have been used. Hence, this project evaluated tumors at numerous AOC and non-AOC sites and compared methodology. In 1998-2000 the prevalence of presumptive orocutaneous tumors and barbel abnormalities was compared in brown bullhead (Ameiurus nebulosus) collected at eight AOC. The Black (46.7%), Buffalo (29.3%), Cuyahoga (58.9%), and Detroit (26.5%) rivers and Presque Isle Bay (28.6%) had high prevalences of orocutaneous tumors, while the Niagara (10%), Maumee (3.9%) and Ashtabula (4.4%) rivers were lower. From 2002 to 2007 the prevalence of orocutaneous tumors at Presque Isle Bay was consistently near 30%. A variety of non-AOC sites, as potential reference sites, were also monitored during this time. By combining years and sites the prevalence of orocutaneous tumors in bullhead (age 2-12 years) at inland lakes was 6.3%, at Long Point Inner Bay was 8.7%, at other bays and harbors was 14.6% and at tributary sites was 12.5%. Overall, 93% of the raised lesions identified as presumptive tumors grossly were verified as neoplasms microscopically. The prevalence of orocutaneous tumors increased with age at both Presque Isle Bay and Long Point Inner Bay, the sites with the largest sample sizes.

  18. Tumor prevalence and biomarkers of exposure in brown bullhead (Ameiurus nebulosus) from Back River, Furnace Creek, and Tuckahoe River, Maryland

    USGS Publications Warehouse

    Pinkney, A.E.; Harshbarger, J.C.; May, E.B.; Melancon, M.J.

    2004-01-01

    Brown bullheads (Ameiurus nebulosus) were collected from 2 locations near Baltimore, Maryland, Back River and Furnace Creek, and 1 (reference) location, Tuckahoe River, to compare the prevalence of tumors (liver and skin) and visible skin lesions (fin erosion and abnormal barbels). Cytochrome P450 activity measured as ethoxyresorufin-O-deethylase, biliary PAH-like fluorescent metabolites, and fillet contaminant concentrations were determined as indicators of exposure in a randomly selected subset of the fish. There were no significant differences in liver tumor prevalence: Back River = 8% (4/50), Furnace Creek = 0% (0/50), and Tuckahoe River = 2.6% (1/39; p = 0.20, extension of Fishers exact test). Skin tumor prevalence was as follows: Furnace Creek = 12% (6/50), Back River = 8% (4/50), and Tuckahoe River = 0% (0/39; p = 0.063). In the Back River fish, there was a 40% (20/50) prevalence of fin erosion and a 28% (14/50) prevalence of abnormal (shortened, clubbed, or missing) barbels. Fin erosion was not observed in the other collections, and only 10% (5/50) of the Furnace Creek fish had abnormal barbels (p < 0.001 for both lesions). There were statistically significant differences in mean EROD activity, with levels in Furnace Creek and Back River fish approximately twice that found in Tuckahoe River fish. There were also significant differences in mean benzo(a)pyrene-like bile metabolite concentrations: the lowest mean was in the Tuckahoe River fish, 8 times higher in Furnace Creek fish, and 13 times higher in Back River fish. Of the 3 groups, the Back River bullheads appear to be most adversely affected by contaminant exposure because they had the highest prevalence of liver tumors, fin erosion, and abnormal barbels.

  19. Assessing the ecosystem service potential of Tucson AZ's urban forest

    NASA Astrophysics Data System (ADS)

    Pavao-Zuckerman, M.

    2011-12-01

    Urbanization is arguably one of the most dramatic forms of landscape change, and an important anthropogenic influence on the structure and function of ecosystems. Cities have obvious impacts on local ecologies and environments, such as shifts in species diversity and alteration of local microclimates. While scientists are now familiar with many of these localized impacts of urbanization, cities and suburban areas contribute to 10-15 % of surface land cover in the conterminous U.S., pointing to the potential, yet poorly understood, contribution of cities to regional, national, and global carbon (C) and energy budgets. As cities continue to expand urban ecologists place more emphasis on understanding the functions of urban ecosystems and the ecosystem services (e.g. habitat, air, and water quality) that cities provide. While studies demonstrate that the urban environment alters the structure and function of remnant patches of native ecosystems relative to their non-urban counterparts, the ability of restoration, planning, and design to improve the provision of ecosystem services is a new approach within ecology. One strategy involves green urban design, or using ecological principles for planning or reinvigorating certain ecological processes, in cities. Increasing the amount of vegetative cover can reduce this effect by reinforcing ecosystem services in cities, including shading of surfaces, promotion of cooling through evapotranspiration, and the sequestration of atmospheric CO2 in plant tissues and soils. However, the on-the-ground reality of such strategies is relatively unknown. A pilot study is being conducted in Tucson, AZ to investigate the impact of increasing the cover of trees in the urban landscape on local microclimates and the urban heat island. Trees (Velvet Mesquite, Chilean Mesquite, and Desert Willow) were planted in two neighborhoods in Tucson in 1990. We are collecting data during the summer 2011 monsoon (DBH, crown volume, and hemispherical

  20. 33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Casino. Parker Thanksgiving Regatta Sponsor: Southern California Speedboat Club Date: Four-day event during Thanksgiving Where: that portion of Lake Moovalya, Parker, Arizona between the northern and...: Havasu Sports Federation Date: 5 day event during Thanksgiving weekend Where: that portion of...

  1. 33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Casino. Parker Thanksgiving Regatta Sponsor: Southern California Speedboat Club Date: Four-day event during Thanksgiving Where: that portion of Lake Moovalya, Parker, Arizona between the northern and...: Havasu Sports Federation Date: 5 day event during Thanksgiving weekend Where: that portion of...

  2. 33 CFR 100.1102 - Annual marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... application each year as required by 33 CFR part 100, subpart A, to the cognizant Coast Guard Sector Commander.... Bluewater Resort and Casino Thanksgiving Regatta Sponsor Southern California Speedboat Club. Event Description Boat Races. Date Thursday, Friday, Saturday, and Sunday during Thanksgiving week. Location...

  3. 33 CFR 100.1102 - Annual marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... application each year as required by 33 CFR part 100, subpart A, to the cognizant Coast Guard Sector Commander.... Bluewater Resort and Casino Thanksgiving Regatta Sponsor Southern California Speedboat Club. Event Description Boat Races. Date Thursday, Friday, Saturday, and Sunday during Thanksgiving week. Location...

  4. 33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...°01′05″N, 114°38′20″ W. 5. Colorado Belle & Edgewater Hotel/Casino Thanksgiving Fireworks Sponsor Edgewater Hotel & Casino Event Description Fireworks Display. Date One evening during Thanksgiving...

  5. A comparison of β-adrenoceptors and muscarinic cholinergic receptors in tissues of brown bullhead catfish (Ameiurus nebulosus) from the black river and old woman creek, Ohio

    USGS Publications Warehouse

    Steevens, Jeffery A.; Baumann, Paul C.; Jones, Susan B.

    1996-01-01

    β-Adrenoceptors (βARs) and muscarinic cholinergic receptors were measured in brain, gill, and heart tissues of brown bullhead catfish exposed to polycyclic aromatic hydrocarbons in the Black River, Ohio, USA, and were compared to values from Old Woman Creek, Ohio, a reference site. A decreased number of βARs were found in the gill from Black River fish, possibly indicating a compensatory response subsequent to chemical stress.

  6. A comparison of {beta}-adrenoceptors and muscarinic cholinergic receptors in tissues of brown bullhead catfish (Ameiurus nebulosus) from the Black River and Old Woman Creek, Ohio

    SciTech Connect

    Steevens, J.A.; Baumann, P.C.; Jones, S.B.

    1996-09-01

    {beta}-Adrenoceptors ({beta}ARs) and muscarinic cholinergic receptors were measured in brain, gill, and heart tissues of brown bullhead catfish exposed to polycyclic aromatic hydrocarbons in the Black River, Ohio, USA, and were compared to values from Old Woman Creek, Ohio, a reference site. A decreased number of {beta}ARs were found in the gill from Black River fish, possibly indicating a compensatory response subsequent to chemical stress.

  7. 76 FR 619 - Arizona Disaster #AZ-00014

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-05

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arizona Disaster AZ-00014 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of Arizona (FEMA- 1950-DR), dated 12/21/2010. Incident: Severe Storms and Flooding....

  8. 76 FR 42156 - Arizona Disaster #AZ-00016

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... ADMINISTRATION Arizona Disaster AZ-00016 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Arizona dated 07/11... adversely affected by the disaster: Primary Counties: Cochise. Contiguous Counties: Arizona:...

  9. 76 FR 45644 - Arizona Disaster #AZ-00016

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-29

    ... ADMINISTRATION Arizona Disaster AZ-00016 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of disaster for the State of Arizona dated 07/11... INFORMATION: The notice of the Administrator's disaster declaration for the State of Arizona, dated...

  10. 75 FR 45680 - Arizona Disaster #AZ-00010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ... ADMINISTRATION Arizona Disaster AZ-00010 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Arizona dated 07/27... adversely affected by the disaster: Primary Counties: Gila; Yavapai. Contiguous Counties: Arizona:...

  11. 75 FR 75720 - Arizona Disaster #AZ-00012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-06

    ... ADMINISTRATION Arizona Disaster AZ-00012 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY... the State of Arizona (FEMA-1940-DR), dated 10/04/2010. Incident: Severe Storms and Flooding. Incident... Private Non-Profit organizations in the State or Arizona, dated 10/04/2010, is hereby amended to...

  12. 78 FR 57923 - Arizona Disaster #AZ-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-20

    ... ADMINISTRATION Arizona Disaster AZ-00029 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Arizona dated 09/13/2013... adversely affected by the disaster: Primary Counties: Yavapai. Contiguous Counties: Arizona: Coconino,...

  13. Biochemistry Games: "AZ-Quiz" and "Jeopardy!"

    ERIC Educational Resources Information Center

    Rostejnska, Milada; Klimova, Helena

    2011-01-01

    "AZ-Quiz" and "Jeopardy!" are popular television shows and serve as the basis for in-class games designed to support and diversify chemistry instruction at the high school level. Both games were created in Microsoft PowerPoint, which is an easily accessible and controllable instrument that enables the creation of engaging animation. The use of…

  14. Monitoring exposure of brown bullheads and benthic macroinvertebrates to sediment contaminants in the Ashtabula River before, during, and after remediation.

    PubMed

    Meier, John R; Lazorchak, James M; Mills, Marc; Wernsing, Paul; Baumann, Paul C

    2015-06-01

    In 2007, approximately 420,500 cubic meters of contaminated sediment were removed from the Ashtabula River by dredging. The primary objective of the present study was to monitor contaminant exposure in fish and macroinvertebrates before, during, and after dredging. This was done by measuring tissue concentrations of polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH) in brown bullhead catfish (Ameriurus nebulosa) and in benthic macroinvertebrates, assessing changes in DNA damage in fish liver and blood, and scoring external and histopathological lesions and anomalies in the fish. In surficial sediment PCBs and PAHs were also quantified in conjunction with the biological sampling. The results show a significant reduction in contaminant levels in both fish and macroinvertebrates following dredging, indicating the effectiveness of the remediation in reducing exposure of biota to the primary contaminants of concern. Similarly, DNA damage levels in fish collected from the Ashtabula River significantly declined following dredging; however, a similar reduction in DNA damage over time was seen in fish collected from a reference site (Conneaut Creek), making interpretation difficult. Macroinvertebrate PCB concentrations were reflective of the sediment concentrations in the areas where Hester-Dendy samplers were deployed for macroinvertebrate collection. The present study demonstrates that these methods can be used to evaluate and assess the effectiveness of remediation techniques at contaminated sediment sites. PMID:25565098

  15. Monitoring exposure of brown bullheads and benthic macroinvertebrates to sediment contaminants in the Ashtabula River before, during, and after remediation.

    PubMed

    Meier, John R; Lazorchak, James M; Mills, Marc; Wernsing, Paul; Baumann, Paul C

    2015-06-01

    In 2007, approximately 420,500 cubic meters of contaminated sediment were removed from the Ashtabula River by dredging. The primary objective of the present study was to monitor contaminant exposure in fish and macroinvertebrates before, during, and after dredging. This was done by measuring tissue concentrations of polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH) in brown bullhead catfish (Ameriurus nebulosa) and in benthic macroinvertebrates, assessing changes in DNA damage in fish liver and blood, and scoring external and histopathological lesions and anomalies in the fish. In surficial sediment PCBs and PAHs were also quantified in conjunction with the biological sampling. The results show a significant reduction in contaminant levels in both fish and macroinvertebrates following dredging, indicating the effectiveness of the remediation in reducing exposure of biota to the primary contaminants of concern. Similarly, DNA damage levels in fish collected from the Ashtabula River significantly declined following dredging; however, a similar reduction in DNA damage over time was seen in fish collected from a reference site (Conneaut Creek), making interpretation difficult. Macroinvertebrate PCB concentrations were reflective of the sediment concentrations in the areas where Hester-Dendy samplers were deployed for macroinvertebrate collection. The present study demonstrates that these methods can be used to evaluate and assess the effectiveness of remediation techniques at contaminated sediment sites.

  16. Egg Development of the Ussurian Bullhead Fish, Leiocassis ussuriensis (Pisces: Bagridae) and Morphological Development of Its Larvae and Juveniles.

    PubMed

    Park, Jae-Min; Yim, Hu-Sun; Lee, Yong-Sik; Kim, Heung-Yun; Han, Kyeong-Ho

    2015-12-01

    This study was examined the ovogenesis of Ussurian bullhead, Leiocassis ussuriensis and the morphological development of its larvae and juveniles and to use the results as basic information for the preservation of species and resource enhancement. For artificial egg collection, human chorionic gonadotropin (HCG) was injected at a rate of 10 IU per gram of fish weight. During breeding period, water temperature maintained at 24.5~26.5°C (mean 25.0±0.05°C). The process of ovogenesis reached the two-cell stage in 50 minutes after fertilization. In 73 hours of fertilization the movement of the embryoid body became active state and the larvae began to hatch from the tail through the oolemma. Length of prelarvae were 6.33~6.50 mm long (mean 6.40±0.06 mm) just after hatching having yolk with their mouth not opened. After thirty eight days of hatching, juveniles were 30.6∼32.5 mm long (mean 31.5±0.65 mm). The color was dark yellowish brown throughout the entire body, and the number of caudal fin rays developed to thirty six perfectly.

  17. 11. Park Avenue Streetscape, looking southeast. AZ184 (Clifton Water and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Park Avenue Streetscape, looking southeast. AZ-184 (Clifton Water and Improvement Company Building), AZ-185 (Tailor Shop), AZ-186(Hampton Block), AZ-187(C. F. Pascoe Undertaking) visible at left. - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  18. The extreme Centaur 2013 AZ_{60}

    NASA Astrophysics Data System (ADS)

    Kiss, C.; Horner, J.; Pal, A.; Szakats, R.; Vilenius, E.; Acosta-Pulido, J.; Sarneczky, K.; Szabo, G.; Duffard, R.

    2014-07-01

    2013 AZ_{60} is an extreme Centaur moving on a highly eccentric orbit of e = 0.9922, with a semimajor axis of 1021.09 au, and a perihelion distance of 7.91 au. 2013 AZ_{60} was observed with the PACS camera of the Herschel Space Observatory, and, using these thermal emission measurements, we were able to derive an effective size of 66.5±3.7 km in diameter, and a geometric albedo of p_V=0.026±0.003. Photometric measurements revealed a low-amplitude lightcurve (0.045±0.007mag in the r' band) with a likely full period of P=9.39 h. The dynamical analysis shows that the orbit of 2013 AZ_{60} is highly unstable, with a ˜50 per cent probability that the target is ejected from the Solar System after about 700 kyr. This high level of instability indicates that 2013 AZ_{60} may just have recently been captured to its current orbit. Investigating the total time the target could have spent at small heliocentric distances (< 100 au), it seems to be likely that this has only been at most 100 to 1000 years and it has a low probability that the target could reach Earth-crossing orbits (i.e., < 1 au). As the likely origin of this target is the Oort Cloud, these together suggests a relatively unaltered, pristine surface, in contradiction with the very low albedo (˜2.6 per cent) derived from the thermal infrared measurements which rather indicates an ''extinct cometary'' surface, also in agreement with the photometric colors.

  19. Metabolism of benzo[a]pyrene and (-)-trans-benzo[a]pyrene-7,8-dihydrodiol by freshly isolated hepatocytes of brown bullheads.

    PubMed

    Steward, A R; Zaleski, J; Sikka, H C

    1990-01-01

    The metabolism of [3H]benzo[a]pyrene (BP) and (-)-trans-[14C]7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) was studied in freshly isolated hepatocytes of the wild benthic fish, brown bullhead (Ictalurus nebulosus). Bullhead hepatocytes incubated with 40 microM [3H]BP for 1 h metabolized BP to water soluble metabolites which were separated on silica gel t.l.c. plates to reveal conjugates with glucuronic acid, glutathione, and sulfate (51%, 14% and 4% of total metabolites, respectively). Additional metabolites that were extractable with ethyl acetate were separated by reversed phase HPLC to reveal only two major metabolites: BP-9,10-dihydrodiol and BP-7,8-diol (13% and 2.6% of total metabolites, respectively). Hepatocytes isolated from individual fish displayed an 11-fold variability in the rates at which they metabolized BP (756 +/- 167 pmol x mg dry wt-1 x h-1), which correlated negatively (r = -0.7, P less than 0.01) with an 18-fold variability in the glycogen content of the cells. Hepatocytes isolated from the same fish, in parallel incubations under the same optimum conditions, metabolized BP-7,8-diol 4.5-fold faster than they metabolized BP. The variability in the rate of BP-7,8-diol metabolism was about 7-fold. Major metabolites included glutathione conjugates, glucuronides and sulfates (35%, 25% and 30% of total metabolites, respectively). These conjugates, like those formed from BP, were degradable with gamma-glutamyltransferase, beta-glucuronidase and arylsulfatase, respectively. Ethyl acetate extractable metabolites were predominantly isomeric benzo-ring tetrahydrotetrols (9% of total metabolites). In summary, this study indicates that during short-term incubations bull-head hepatocytes metabolize BP and BP-7,8-diol primarily to conjugated derivatives. The usefulness of thin-layer chromatography for the convenient determination of the rate of BP-7,8-diol metabolism is demonstrated.

  20. Computer simulation of the leaching and washing of waste in tanks C-106, AY-102, AZ-101, and AZ-102

    SciTech Connect

    MacLean, G.T.

    1997-05-01

    The waste in underground storage tanks C-106, AY-102, AZ-101, and AZ-102 will be used to prepare feed material for the proposed high level waste vitrification demonstration plant at Hanford. A chemical process simulation computer program called the Environment Simulation Program (ESP) was used to estimate the compositions and quantities of this waste and the products after pretreatment processing. The amount of precipitated material in Tank C-106 predicted to be dissolved by sluicing is 27 wt.%. The amount of precipitated material predicted to be dissolved by mild leaching is about 30% for the C-106 and AY-102 combined waste and about 50% for AZ-101, and 35% for AZ-102 wastes. The predicted caustic solution raw material requirements for leaching are 158 m{sup 3} for C-106 and AY-102, 60 m{sup 3} for AZ-101, and 146 m{sup 3} for AZ-102, all as 50 wt.% NAOH.

  1. 16. Park Avenue streetscape, looking northwest AZ191 (Clifton Mineral Hot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Park Avenue streetscape, looking northwest AZ-191 (Clifton Mineral Hot Springs Bath House) at center, AZ-193 (Presbyterian Church) at right. - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  2. 13. Coronado Boulevard streetscape, looking southeast. AZ180 (Arizona and New ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Coronado Boulevard streetscape, looking southeast. AZ-180 (Arizona and New Mexico Railroad Passenger Depot) at left, AZ-178 (Arizona Copper Company Office) at right. - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  3. 15. View to the northwest along railroad tracks. AZ180 (Arizona ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. View to the northwest along railroad tracks. AZ-180 (Arizona and New Mexico Railroad Passenger Depot) at left. In the background can be seen, left to right, AZ-178 (Arizona Copper Company Office), AZ-177 (Arizona Copper Company Library Hall), AZ-179 (Park Avenue Bridge) and AZ-183 (La Casa Grande). - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  4. Tumor Prevalence and Biomarkers of Exposure and Response in Brown Bullheads (Ameiurus nebulosus) from the Tidal Potomac River Watershed

    USGS Publications Warehouse

    Pinkney, A.E.; Harshbarger, J.C.; May, E.B.; Melancon, M.J.

    2000-01-01

    Four groups of thirty brown bullheads (Ameiurus nebulosus) were collected from the tidal Potomac River watershed to survey tumor prevalence in relation to contaminant exposure. Fish were obtained from the Quantico embayment, near a Superfund site that released polychlorinated biphenyls (PCBs) and DDT compounds; Neabsco Creek,.a tributary with petroleum inputs from upstream areas and marinas; and the Anacostia River (both in spring and fall),where sediment is contaminated with polynuclear aromatic hydrocarbons (PAHs), PCBs, and organochlorine pesticides. Fish were also collected from the Tuckahoe River, on the Eastern Shore of Maryland, as a reference. Fish were necropsied and examined grossly and histopathologically for skin and liver neoplasms. Cytochrome P450 activity, bile PAH metabolites, and muscle organochlorine pesticide/PCB concentrations were determined in randomly selected individuals. There were significant differences among sites in liver tumor prevalence: Anacostia (spring)-50%, Anacostia (fall)-60%, Neabsco-17%, Quantico-7%, Tuckahoe-10%. Skin tumor prevalences were also significantly different: Anacostia (spring)-37%, Anacostia (fall)-10%, Neabsco-3%, Quantico-3%, Tuckahoe-0%. Tumor prevalences in Anacostia fish were comparable to those at contaminated sites in the Great Lakes. PAH concentrations were higher in Anacostia sediments than at the other sites and there were significantly higher concentrations of PAH metabolites in bile of the Anacostia fish. At present, there are insufficient data, however, to establish a cause-effect linkage with a particular class of contaminants. Tumor surveys in selected species are recommended for monitoring the status and remediation of Regions of Concern and other areas in the Chesapeake Bay watershed.

  5. Tumors in brown bullheads in the Chesapeake Bay watershed: analysis of survey data from 1992 through 2006.

    PubMed

    Pikney, Alfred E; Harshbarger, John C; Rutter, Michael A

    2009-06-01

    Liver and skin tumor prevalences in brown bullheads Ameiurus nebulosus have been used in the North American Great Lakes to designate highly contaminated areas of concern and monitor their recovery. Here we interpret the results of six surveys conducted in the Chesapeake Bay watershed between 1992 and 2006, with data for 647 fish. The objective has been to develop an adequate database to critically evaluate the use of tumor prevalence as a habitat quality indicator within the watershed. Surveys featured randomized fish collection; recording of sex, length, weight, and age; and histopathology of all livers and all raised skin lesions. The Bayes information criterion was used to analyze all possible combinations of age, gender, length, and weight as covariates for logistic regression. Length and gender were the covariates that best described liver tumor prevalence. There were no covariates in the model for skin tumor prevalence. In some surveys, biomarkers, such as biliary polynuclear aromatic hydrocarbon (PAH)-like metabolites, hepatic cytochrome P450 activity, and hepatic DNA adducts, were used with sediment and tissue chemistry data to evaluate classes of chemicals as likely contributors to tumor prevalence. We highlight two surveys of the Anacostia River, Washington, D.C. (average = 55% liver tumors, 23% skin tumors), where sediment PAHs, biliary PAH-like metabolites, and hepatic DNA adducts were high, suggesting that PAHs play a major role. We show that logistic regression is an appropriate procedure for comparing "contaminated" versus "reference" locations, and we evaluate the utility of tumor surveys as an environmental indicator for the Chesapeake Bay watershed.

  6. Assessment of Debris Flow Hazards, North Mountain, Phoenix, AZ

    NASA Astrophysics Data System (ADS)

    Reavis, K. J.; Wasklewicz, T. A.

    2014-12-01

    Urban sprawl in many western U.S. cities has expanded development onto alluvial fans. In the case of metropolitan Phoenix, AZ (MPA), urban sprawl has led to an exponential outward growth into surrounding mountainous areas and onto alluvial fans. Building on alluvial fans places humans at greater risk to flooding and debris flow hazards. Recent research has shown debris flows often supply large quantities of material to many alluvial fans in MPA. However, the risk of debris flows to built environments is relatively unknown. We use a 2D debris flow modeling approach, aided by high-resolution airborne LiDAR and terrestrial laser scanning (TLS) topographic data, to examine debris flow behavior in a densely populated portion of the MPA to assess the risk and vulnerability of debris flow damage to the built infrastructure. A calibrated 2D debris flow model is developed for a "known" recent debris flow at an undeveloped site in MPA. The calibrated model and two other model scenarios are applied to a populated area with historical evidence of debris flow activity. Results from the modeled scenarios show evidence of debris flow damage to houses built on the alluvial fan. Debris flow inundation is also evident on streets on the fan. We use housing values and building damage to estimate the costs assocaited with various modeled debris flow scenarios.

  7. ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN

    SciTech Connect

    DUNCAN JB; FRYE JM; COOKE CA; LI SW; BROCKMAN FJ

    2006-12-13

    This report presents the analyses results for three samples obtained under RPP-PLAN-28509, Sampling and Analysis Plan for Building 241 702-AZ A Train. The sampling and analysis was done in response to problem evaluation request number PER-2004-6139, 702-AZ Filter Rooms Need Radiological Cleanup Efforts.

  8. 241-AZ Farm Annulus Extent of Condition Baseline Inspection

    SciTech Connect

    Engeman, Jason K.; Girardot, Crystal L.; Vazquez, Brandon J.

    2013-05-15

    This report provides the results of the comprehensive annulus visual inspection for tanks 241- AZ-101 and 241-AZ-102 performed in fiscal year 2013. The inspection established a baseline covering about 95 percent of the annulus floor for comparison with future inspections. Any changes in the condition are also included in this document.

  9. 76 FR 78180 - Proposed Modification of Class E Airspace; Douglas, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ... AZ E2 Douglas, AZ Bisbee Douglas International Airport, AZ (Lat. 31 28'08'' N., long. 109 36'14'' W... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of Class E Airspace; Douglas, AZ...: This action proposes to modify Class E airspace at Bisbee Douglas International Airport, Douglas,...

  10. Series of AZ-compatible negative photoresists

    NASA Astrophysics Data System (ADS)

    Voigt, Anya; Gruetzner, Gabi; Sauer, E.; Helm, S.; Harder, T.; Fehlberg, Simone; Bendig, Juergen

    1995-06-01

    A series of AZ-compatible negative photoresists composed of a novolak resin and azide sensitizers for the micro and nano-lithography is presented. The ma-N 2400 and ma-N 300 are sensitive to light of the deep UV region (248 nm, 254 nm, 308 nm), the ma-N 400 and ma-N 1400 are sensitive to light of the mid UV region, the latter has a high sensitivity to the i-line (365 nm). The thickness of the resist layers prepared by spin coating is up to 8 micrometers depending on the composition of the resist solution. All resists are non-swelling during aqueous alkaline development after exposure. Using special lithography, these photoresists have a resolution capability up to 0.1 micrometers . The resistance to wet etch solutions and to dry etch gases is superior and higher than that of the most positive resists based on novolak.

  11. 75 FR 81190 - Television Broadcasting Services; Yuma, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Yuma, AZ AGENCY: Federal Communications Commission. ACTION: Dismissal. SUMMARY: The Commission dismisses the petition for rulemaking filed by...

  12. Semi empirical hardness predictive model for AZ91 nanocomposite

    NASA Astrophysics Data System (ADS)

    Zaidi, N. H. A.; Jamaludin, S. B.; Zaidi, A. M. A.; Ahmad, K. R.

    2016-07-01

    AZ91 nanocomposite was exposed to several heat treatment processes and the effect of precipitation hardening on hardness was studied as a function of time and temperature. The investigation shows the significant of time and temperature are the main role in the precipitation hardening process of the nanocomposite. Kinetics study show a deceptive activation energy of 21 kJ/mol of the AZ91 nanocomposite. A relationship was derived to predict the maximum hardness at given time and temperature.

  13. 75 FR 57327 - Environmental Impact Statement; Pinal County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-20

    ..., San Carlos Apache Nation, White Mountain Apache Tribe, Yavapai-Prescott Indian Tribe, Yavapai-Apache..., City of Eloy, City of Queen Creek, Town of Gilbert, City of Mesa, City of Apache Junction, City of...

  14. Caustic leaching of composite AZ-101/AZ-102 Hanford tank sludge

    SciTech Connect

    Rapko, B.M.; Wagner, M.J.

    1997-07-01

    To reduce the quantity (and hence the cost) of glass canisters needed for disposing of high-level radioactive wastes from the Hanford tank farms, pretreatment processes are needed to remove as much nonradioactive material as possible. This report describes the results of a laboratory-scale caustic leaching test performed on a composite derived from a combination of 241-AZ-101 and 241-AZ-102 Hanford Tank sludges. The goals of this FY 1996 test were to evaluate the effectiveness of caustic leaching on removing key components from the sludge and to evaluate the effectiveness of varying the free-hydroxide concentrations by incrementally increasing the free hydroxide concentration of the leach steps up to 3 {und M} free hydroxide. Particle-size analysis of the treated and untreated sludge indicated that the size and range of the sludge particles remained essentially unchanged by the caustic leaching treatment. Both before and after caustic leaching, a particle range of 0.2 {micro}m to 50 {micro}m was observed, with mean particle diameters of 8.5 to 9 {micro}m based on the volume distribution and mean particle diameters of 0.3 to 0.4 {micro}m based on the number distribution.

  15. Microstructure and Tensile Properties of AZ31B Alloy and AZ31B-SiCp Deformed Through a Multi-step Process

    NASA Astrophysics Data System (ADS)

    Shen, M. J.; Wang, X. J.; Ying, T.; Zhang, M. F.; Wu, K.

    2016-08-01

    The 15 vol.% micron SiC particle (SiCp)-reinforced AZ31B magnesium matrix composite (AZ31B-SiCp) prepared with semisolid stirring-assisted ultrasonic vibration was subjected to a multi-step process. The influence of the multi-step processing route on the microstructure and mechanical properties of the AZ31B-SiCp was investigated. For comparison, the monolithic AZ31B alloy was also processed under the same conditions. The results showed that the grain sizes of the AZ31B alloy and the AZ31B-SiCp were gradually decreased with increasing the processing step. Compared with the AZ31B-SiCp, the grain size of the AZ31B alloy was much larger, and the grain size distribution was inhomogeneous at the same processing condition. The particles of the AZ31B-SiCp were dispersed uniformly through the multi-step processing. Moreover, the tensile properties of the materials were gradually improved with increasing the processing step. In particular, the strength of AZ31B-SiCp and the ductility of AZ31B alloy improved significantly based on the room-temperature tensile test results.

  16. Microstructure and Tensile Properties of AZ31B Alloy and AZ31B-SiCp Deformed Through a Multi-step Process

    NASA Astrophysics Data System (ADS)

    Shen, M. J.; Wang, X. J.; Ying, T.; Zhang, M. F.; Wu, K.

    2016-10-01

    The 15 vol.% micron SiC particle (SiCp)-reinforced AZ31B magnesium matrix composite (AZ31B-SiCp) prepared with semisolid stirring-assisted ultrasonic vibration was subjected to a multi-step process. The influence of the multi-step processing route on the microstructure and mechanical properties of the AZ31B-SiCp was investigated. For comparison, the monolithic AZ31B alloy was also processed under the same conditions. The results showed that the grain sizes of the AZ31B alloy and the AZ31B-SiCp were gradually decreased with increasing the processing step. Compared with the AZ31B-SiCp, the grain size of the AZ31B alloy was much larger, and the grain size distribution was inhomogeneous at the same processing condition. The particles of the AZ31B-SiCp were dispersed uniformly through the multi-step processing. Moreover, the tensile properties of the materials were gradually improved with increasing the processing step. In particular, the strength of AZ31B-SiCp and the ductility of AZ31B alloy improved significantly based on the room-temperature tensile test results.

  17. 21. Streetscape, South Coronado Boulevard, looking northwest AZ205 (F. D. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Streetscape, South Coronado Boulevard, looking northwest AZ-205 (F. D. Connor House) is the first house on the left - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  18. 12. Smelter site along Coronado Boulevard, looking east. AZ174(Arizona Copper ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Smelter site along Coronado Boulevard, looking east. AZ-174(Arizona Copper Company Smelter Blower House) near center of photograph. - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  19. 19. View to the north of Riverside Avenue. AZ196(J. C. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. View to the north of Riverside Avenue. AZ-196(J. C. Gatti House) at left Part of AZ-197 (Shannon Copper Company Store) can be seen in group of buildings at right - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

  20. The evolutionary differentiation of two histone H2A.Z variants in chordates (H2A.Z-1 and H2A.Z-2) is mediated by a stepwise mutation process that affects three amino acid residues

    PubMed Central

    Eirín-López, José M; González-Romero, Rodrigo; Dryhurst, Deanna; Ishibashi, Toyotaka; Ausió, Juan

    2009-01-01

    Background The histone H2A family encompasses the greatest number of core histone variants of which the replacement variant H2A.Z is currently one of the most heavily studied. No clear mechanism for the functional variability that H2A.Z imparts to chromatin has yet been proposed. While most of the past studies have referred to H2A.Z generically as a single protein, in vertebrates it is a mixture of two protein forms H2A.Z-1 (previously H2A.Z) and H2A.Z-2 (previously H2A.F/Z or H2A.V) that differ by three amino acids. Results We have performed an extensive study on the long-term evolution of H2A.Z across metazoans with special emphasis on the possible selective mechanisms responsible for the differentiation between H2A.Z-1 and H2A.Z-2. Our results reveal a common origin of both forms early in chordate evolution. The evolutionary process responsible for the differentiation involves refined stepwise mutation change within the codons of the three differential residues. This eventually led to differences in the intensity of the selective constraints acting upon the different H2A.Z forms in vertebrates. Conclusion The results presented in this work definitively reveal that the existence of H2A.Z-1 and H2A.Z-2 is not a whim of random genetic drift. Our analyses demonstrate that H2A.Z-2 is not only subject to a strong purifying selection but it is significantly more evolutionarily constrained than H2A.Z-1. Whether or not the evolutionary drift between H2A.Z-1 and H2A.Z-2 has resulted in a functional diversification of these proteins awaits further research. Nevertheless, the present work suggests that in the process of their differently constrained evolutionary pathways, these two forms may have acquired new or complementary functions. PMID:19193230

  1. Age 55 or better: active adult communities and city planning.

    PubMed

    Trolander, Judith Ann

    2011-01-01

    Active adult, age-restricted communities are significant to urban history and city planning. As communities that ban the permanent residence of children under the age of nineteen with senior zoning overlays, they are unique experiments in social planning. While they do not originate the concept of the common interest community with its shared amenities, the residential golf course community, or the gated community, Sun Cities and Leisure Worlds do a lot to popularize those physical planning concepts. The first age-restricted community, Youngtown, AZ, opened in 1954. Inspired by amenity-rich trailer courts in Florida, Del Webb added the “active adult” element when he opened Sun City, AZ, in 1960. Two years later, Ross Cortese opened the first of his gated Leisure Worlds. By the twenty-first century, these “lifestyle” communities had proliferated and had expanded their appeal to around 18 percent of retirees, along with influencing the design of intergenerational communities.

  2. 76 FR 45177 - Establishment of Class E Airspace; Kayenta, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at Kayenta Airport... Federal Register a notice of proposed rulemaking to establish controlled airspace at Kayenta, AZ (76 FR... a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26,...

  3. 77 FR 10649 - Modification of Class E Airspace; Douglas, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-23

    ... proposed rulemaking to amend controlled airspace at Douglas, AZ (76 FR 78180). Interested parties were... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in...

  4. 75 FR 57383 - Modification of Class E Airspace; Willcox, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... Federal Register a notice of proposed rulemaking to amend controlled airspace at Willcox, AZ (75 FR 33561... Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a... follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963...

  5. 76 FR 57634 - Establishment of Class E Airspace; Chinle, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... Federal Register a notice of proposed rulemaking to establish controlled airspace at Chinle, AZ (76 FR... a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in...

  6. Mixer pump test plan for double shell tank AZ-101

    SciTech Connect

    STAEHR, T.W.

    1999-05-12

    Mixer pump systems have been chosen as the method for retrieval of tank wastes contained in double shell tanks at Hanford. This document describes the plan for testing and demonstrating the ability of two 300 hp mixer pumps to mobilize waste in tank AZ-101. The mixer pumps, equipment and instrumentation to monitor the test were installed by Project W-151.

  7. 76 FR 18378 - Amendment of Class E Airspace; Taylor, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ... names to Taylor Airport, and Show Low Regional Airport, respectively. Additionally, the geographic... amend controlled airspace at Taylor, AZ (76 FR 3570). Interested parties were invited to participate in this rulemaking effort by submitting written comments on the proposal to the FAA. No comments...

  8. 75 FR 883 - Environmental Impact Statement; Maricopa County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... Federal Highway Administration Environmental Impact Statement; Maricopa County, AZ AGENCY: Federal Highway... public that an Environmental Impact Statement will be prepared for a proposed highway project in Maricopa... prepare an Environmental Impact Statement (EIS) on proposed operational improvements to the Interstate...

  9. 78 FR 3877 - Radio Broadcasting Services; Peach Springs, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-17

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal Communications... the Hualapai Tribe, proposing to amend the Table of Allotments by allotting Channel 265A at Peach... second potential service at Peach Springs. Channel 265A can be allotted at Peach Springs, Arizona,...

  10. 75 FR 19250 - Safety Zone; BWRC Spring Classic, Parker, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ..., Arizona for the Blue Water Resort and Casino Spring Classic. This temporary safety zone is necessary to... Speedboat Club is sponsoring the Blue Water Resort and Casino Spring Classic, which is held on the Lake... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; BWRC Spring Classic, Parker, AZ...

  11. 78 FR 19988 - Safety Zone; BWRC Spring Classic, Parker, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-03

    ..., Arizona for the Blue Water Resort and Casino Spring Classic. This temporary safety zone is necessary to... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; BWRC Spring Classic, Parker, AZ AGENCY... Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History and Information...

  12. Influence of artificial biological fluid composition on the biocorrosion of potential orthopedic Mg-Ca, AZ31, AZ91 alloys.

    PubMed

    Gu, X N; Zheng, Y F; Chen, L J

    2009-12-01

    The electrochemical behavior of potential orthopedic Mg-Ca, AZ31 and AZ91 alloys was studied in Hank's solution, Dulbecco's Modified Eagle's Medium (DMEM) and serum-containing medium (DMEM adding 10% fetal bovine serum (DMEM+FBS)) over a 7 day immersion period. The biocorrosion of the above three alloys for various immersion time intervals was investigated by linear polarization and electrochemical impedance spectroscopy (EIS). After 7 day immersion, potentiodynamic polarization tests were carried out and the surface morphologies of experimental samples were examined by scanning electron microscopy (SEM) observation complemented by energy-disperse spectrometer (EDS) analysis. It was shown that the corrosion of magnesium alloys was influenced by the composition of the solution. The results indicated that chloride ion could reduce the corrosion resistance and the hydrocarbonate ions could induce rapid surface passivation. The adsorbed amino acid on the experimental magnesium alloys' surface increased their polarization resistance and reduced current densities. The influence of the serum protein on corrosion was found to be associated with the magnesium alloy compositions. A Mg-Ca alloy exhibited an increased corrosion rate in the presence of serum protein. An AZ31 alloy showed an increased corrosion rate in DMEM+FBS in the initial 3 day immersion and the corrosion rate decreased thereafter. An AZ91 alloy, with high Al content, showed a reduced corrosion rate with the addition of FBS into DMEM.

  13. Constitutive turnover of histone H2A.Z at yeast promoters requires the preinitiation complex

    PubMed Central

    Tramantano, Michael; Sun, Lu; Au, Christy; Labuz, Daniel; Liu, Zhimin; Chou, Mindy; Shen, Chen; Luk, Ed

    2016-01-01

    The assembly of the preinitiation complex (PIC) occurs upstream of the +1 nucleosome which, in yeast, obstructs the transcription start site and is frequently assembled with the histone variant H2A.Z. To understand the contribution of the transcription machinery in the disassembly of the +1 H2A.Z nucleosome, conditional mutants were used to block PIC assembly. A quantitative ChIP-seq approach, which allows detection of global occupancy change, was employed to measure H2A.Z occupancy. Blocking PIC assembly resulted in promoter-specific H2A.Z accumulation, indicating that the PIC is required to evict H2A.Z. By contrast, H2A.Z eviction was unaffected upon depletion of INO80, a remodeler previously reported to displace nucleosomal H2A.Z. Robust PIC-dependent H2A.Z eviction was observed at active and infrequently transcribed genes, indicating that constitutive H2A.Z turnover is a general phenomenon. Finally, sites with strong H2A.Z turnover precisely mark transcript starts, providing a new metric for identifying cryptic and alternative sites of initiation. DOI: http://dx.doi.org/10.7554/eLife.14243.001 PMID:27438412

  14. Education Cities

    ERIC Educational Resources Information Center

    Shaked, Haim

    2014-01-01

    In recent years, several cities in Israel have labeled themselves "Education Cities," concentrating on education as their central theme. Employing qualitative techniques, this article aims to describe, define, and conceptualize this phenomenon as it is being realized in three such cities. Findings show that Education Cities differ from…

  15. Nature of the 1100 Micron AzTEC-COSMOS Sources

    NASA Astrophysics Data System (ADS)

    Yun, Min Su; Aguirre, J.; Aretxaga, I.; Austermann, J.; Bock, J.; Fazio, G.; Huang, J.; Hughes, D.; Kang, Y.; Kim, S.; Lowenthal, J.; Ma, C.; Mauskopf, P.; Perera, T.; Sanders, D.; Scott, K.; Scoville, N.; Wilson, G.; Yoon, I.

    2006-12-01

    The Cosmic Evolution Survey (COSMOS) is a 2 square degree HST/ACS survey specifically designed to probe galaxy evolution as a function of time and environment (PI: N. Scoville). To take advantage of the extensive complementary databases already available through the COSMOS collaboration, we have undertaken a 1100 micron imaging survey of a 30' x 30' field centered just north of the earlier mm/submm surveys by the Bolocam on CSO and MAMBO on the IRAM 30-m telescope. In this poster paper, we will compare the results of the AzTEC and Bolocam surveys and discuss the nature of the AzTEC sources based on the existing multi-wavelength data in hand.

  16. The Corrosion Protection of Magnesium Alloy AZ31B

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Mitchell, M. L.; Torres, P. D.

    1997-01-01

    Corrosion rates for bare and coated Magnesium alloy AZ31B have been measured. Two coatings, Dow-23(Trademark) and Tagnite(Trademark), have been tested by electrochemical methods and their effectiveness determined. Electrochemical methods employed were the scanning reference electrode technique (SRET), the polarization resistance technique (PR) and the electrochemical impedance spectroscopy technique (EIS). In addition, general corrosion and stress corrosion methods were employed to examine the effectiveness of the above coatings in 90 percent humidity. Results from these studies are presented.

  17. Glucose tolerance and peripheral glucose utilization in rainbow trout (Oncorhynchus mykiss), American eel (Anguilla rostrata), and black bullhead catfish (Ameiurus melas).

    PubMed

    Legate, N J; Bonen, A; Moon, T W

    2001-04-01

    This study tests the hypothesis that glucose tolerance in fish is related to nutrient preference and is correlated with white muscle glucose transporter and phosphorylation (hexokinase) activities. Glucose clearance was investigated in the carnivorous rainbow trout (Oncorhynchus mykiss) and American eel (Anguilla rostrata) (feeding and fasting) and the omnivorous black bullhead catfish (Ameiurus melas). Glucose tolerance was assessed by an intravenous glucose tolerance test, injecting 250 mg glucose/kg body weight and tracking blood glucose concentrations over 24 h. Both feeding eel and feeding catfish returned plasma glucose levels to baseline within 60 min of glucose injection. Glucose values remained elevated for more than 360 min in both the food-deprived eel and the feeding rainbow trout. Glucose transport studies in white muscle membrane vesicles provided evidence for the presence of a stereospecific, saturable glucose transporter in all three species. Affinity constants (K(m)) ranged from 8 to 14 mM while V(max) values ranged from 75 to 150 pmol/s/mg protein. Neither kinetic parameter differed significantly between species. Cytochalasin B and phloretin did not significantly inhibit glucose transport, implying that these transporters are unlike the mammalian muscle glucose transporters (GLUT). In fact, Northern and Western blot analyses of mRNA and protein from white and red muscles and heart did not detect a mammalian-type GLUT-1 or -4 in any of the species examined. Glucose phosphorylation indicated the presence of a hexokinase activity (low K(m) enzyme) but again there were no differences in kinetic parameters between species. These studies demonstrate that glucose tolerance in fish is species-dependent but none of the parameters examined clearly differentiate between the species examined. Certainly a stereospecific glucose transporter exists in white skeletal muscle of the fish studied but no molecular or kinetic similarities to the mammalian GLUTs were

  18. 8-Hydroxy-2{prime}-deoxyguanosine (8-OH-dG): A biomarker of oxidative damage in yellow bullheads chronically exposed to low-level radiation

    SciTech Connect

    McCreedy, C.D.; Glickman, L.T.; Jagoe, C.H.

    1995-12-31

    8-hydroxy-2{prime}-deoxyguanosine (8-OH-dG), an oxidation product of the nucleotide deoxyguanosine (dG) was used as a biomarker to assess oxidative damage in brain and gill tissues of yellow bullhead catfish (Ameiurus natalis; n = 18) inhabiting an abandoned reactor reservoir contaminated with low levels of {sup d137}Cs (Pond B, Savannah River Site, SC). DNA was isolated by chloroform-isoamyl extraction, enzymatically digested with Nuclease P1/Calf Intestinal Phosphatase, and analyzed by HPLC with electrochemical detection.Length, weight, age, condition and muscle {sup 137}Cs activity of each fish were also determined. Concentrations of 8-OH-dG were greater in brain than in gill tissues. 8-OH-dG in gill tissues decreased as condition of fish increased, but as age increased, the effect of condition declined. Brain 8-OH-dG concentration was not related to age or condition of fish, but was greater in females and the interaction between gender and {sup 137}Cs was significant. Brain 8-OH-dG was positively associated with muscle {sup 137}Cs concentration among females, but was unrelated to {sup 137}Cs concentration in males. At lower {sup 137}Cs concentrations, females tended to have fewer oxidative DNA adducts in brian than did males. Deposition of somatic lipids into eggs may provide females some anti-oxidant benefit by diminishing the contribution of lipid peroxidation to DNA damage. 8-OH-dG is a sensitive biomarker of low-level radiation exposure, however, its application in fish requires consideration of factors such as gender, age, body-condition, and the tissue type sampled.

  19. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2

    SciTech Connect

    Nishibuchi, Ikuno; Suzuki, Hidekazu; Kinomura, Aiko; Sun, Jiying; Liu, Ning-Ang; Horikoshi, Yasunori; Shima, Hiroki; Kusakabe, Masayuki; Harata, Masahiko; Fukagawa, Tatsuo; Ikura, Tsuyoshi; Ishida, Takafumi; Nagata, Yasushi; Tashiro, Satoshi

    2014-07-15

    Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA

  20. 241-AZ Tank Farm Construction Extent of Condition Review for Tank Integrity

    SciTech Connect

    Barnes, Travis J.; Boomer, Kayle D.; Gunter, Jason R.; Venetz, Theodore J.

    2013-07-30

    This report provides the results of an extent of condition construction history review for tanks 241-AZ-101 and 241-AZ-102. The construction history of the 241-AZ tank farm has been reviewed to identify issues similar to those experienced during tank AY-102 construction. Those issues and others impacting integrity are discussed based on information found in available construction records, using tank AY-102 as the comparison benchmark. In the 241-AZ tank farm, the second DST farm constructed, both refractory quality and tank and liner fabrication were improved.

  1. Plasma electrolytic oxidation coating on AZ91 magnesium alloy modified by neodymium and its corrosion resistance

    NASA Astrophysics Data System (ADS)

    Song, Y. L.; Liu, Y. H.; Yu, S. R.; Zhu, X. Y.; Wang, Q.

    2008-03-01

    Ceramic coatings on the surfaces of Mg-9Al-1Zn (AZ91) magnesium alloy and Mg-9Al-1Zn-1Nd magnesium alloy (AZ91 magnesium alloy modified by neodymium, named as AZ91Nd in this paper) are synthesized in aluminate electrolyte by plasma electrolytic oxidation (PEO) process, respectively. X-ray diffraction and X-ray photoelectron spectroscopy analyses show the PEO coating on the Mg-9Al-1Zn-1Nd alloy comprises not only MgO and Al 2O 3, which are found in the coating on the AZ91 alloy, but also a trace amount of Nd 2O 3. Microstructure observations indicate the addition of Nd can decrease the sizes of β phases and form Al 2Nd intermetallics in the AZ91 alloy. The fine β phases can effectively restrain the formation of unclosed-holes and greatly decrease the sizes of pores in the coating during the PEO process. In addition, the Al 2Nd intermetallics can be completely covered due to the lateral growth of the PEO coatings formed on the α and β phases. As a result, the coating on the AZ91Nd alloy possesses a dense microstructure compared with that on the AZ91 alloy. The following corrosion tests indicate the corrosion resistance of the PEO coating on the AZ91Nd alloy is evidently higher than that of the PEO coating on the AZ91 alloy.

  2. Sensitivity of summer climate to anthropogenic land-cover change over the Greater Phoenix, AZ, region

    USGS Publications Warehouse

    Georgescu, M.; Miguez-Macho, G.; Steyaert, L.T.; Weaver, C.P.

    2008-01-01

    This work evaluates the first-order effect of land-use/land-cover change (LULCC) on the summer climate of one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, AZ, region. High-resolution-2-km grid spacing-Regional Atmospheric Modeling System (RAMS) simulations of three "wet" and three "dry" summers were carried out for two different land-cover reconstructions for the region: a circa 1992 representation based on satellite observations, and a hypothetical land-cover scenario where the anthropogenic landscape of irrigated agriculture and urban pixels was replaced with current semi-natural vegetation. Model output is evaluated with respect to observed air temperature, dew point, and precipitation. Our results suggest that development of extensive irrigated agriculture adjacent to the urban area has dampened any regional-mean warming due to urbanization. Consistent with previous observationally based work, LULCC produces a systematic increase in precipitation to the north and east of the city, though only under dry conditions. This is due to a change in background atmospheric stability resulting from the advection of both warmth from the urban core and moisture from the irrigated area. ?? 2008 Elsevier Ltd. All rights reserved.

  3. CONCENTRATIONS OF PESTICIDE FROM DERMAL SURFACES: A COMPARISON OF NHEXAS & AZ BORDER SAMPLES

    EPA Science Inventory

    NHEXAS-AZ was a statewide survey designed to gather data on the distributions of exposure from various media. Results of intensive sampling were obtained from 179 homes. Border-AZ was a similar study focusing on homes within 40 km of the Arizona-Mexico Border; similar results...

  4. 77 FR 2241 - Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ..., and Williams, AZ; and Application of Univision Radio License Corporation, KHOV-FM, Wickenburg, AZ... by Rocket Radio, Inc., proposes the allotment of FM Channel 287C2 at Williams, Arizona, as the..., to facilitate the Williams allotment, we issue an Order to Show Cause to Univision Radio...

  5. 78 FR 40381 - Establishment of Class E Airspace; Grand Canyon, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-05

    ...) to establish controlled airspace at Grand Canyon, AZ (78 FR 25404). Interested parties were invited... Administration 14 CFR Part 71 Establishment of Class E Airspace; Grand Canyon, AZ AGENCY: Federal Aviation... Canyon VHF Omni-Directional Radio Range/Distance Measuring Equipment (VOR/DME) navigation aid,...

  6. 76 FR 62144 - Environmental Impact Statement for Implementation of Passenger Rail Service Between Tucson, AZ...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ... Federal Railroad Administration Federal Transit Administration Environmental Impact Statement for Implementation of Passenger Rail Service Between Tucson, AZ and Phoenix, AZ AGENCY: Federal Railroad... EIS is the first planning-level tier of the two-tiered environmental review process for the...

  7. Histone H2A.Z and DNA methylation are mutually antagonistic chromatin marks

    PubMed Central

    Zilberman, Daniel; Coleman-Derr, Devin; Ballinger, Tracy; Henikoff, Steven

    2010-01-01

    Eukaryotic chromatin is separated into functional domains differentiated by posttranslational histone modifications, histone variants, and DNA methylation1–6. Methylation is associated with repression of transcriptional initiation in plants and animals, and is frequently found in transposable elements. Proper methylation patterns are critical for eukaryotic development4,5, and aberrant methylation-induced silencing of tumor suppressor genes is a common feature of human cancer7. In contrast to methylation, the histone variant H2A.Z is preferentially deposited by the Swr1 ATPase complex near 5′ ends of genes where it promotes transcriptional competence8–20. How DNA methylation and H2A.Z influence transcription remains largely unknown. Here we show that in the plant Arabidopsis thaliana, regions of DNA methylation are quantitatively deficient in H2A.Z. Exclusion of H2A.Z is seen at sites of DNA methylation in the bodies of actively transcribed genes and in methylated transposons. Mutation of the MET1 DNA methyltransferase, which causes both losses and gains of DNA methylation4,5, engenders opposite changes in H2A.Z deposition, while mutation of the PIE1 subunit of the Swr1 complex that deposits H2A.Z17 leads to genome-wide hypermethylation. Our findings indicate that DNA methylation can influence chromatin structure and effect gene silencing by excluding H2A.Z, and that H2A.Z protects genes from DNA methylation. PMID:18815594

  8. 75 FR 76924 - Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... removes Class E airspace designated as an extension to a Class D or E surface area at Flagstaff Pulliam... remove Class E airspace designated as an extension to a Class D or E surface area at Flagstaff, AZ and to... Class D or Class E surface area. * * * * * AWP AZ E4 Flagstaff, AZ Paragraph 6005 Class E airspace...

  9. 78 FR 71493 - Special Local Regulation; Lake Havasu City Christmas Boat Parade of Lights; Colorado River; Lake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... Acronyms BNM Broadcast Notices to Mariners COTP Captain of the Port DHS Department of Homeland Security FR... Boat Parade of Lights; Colorado River; Lake Havasu, AZ AGENCY: Coast Guard, DHS. ACTION: Temporary... in support of the Lake Havasu City Christmas Boat Parade of Lights on the Colorado River....

  10. Comment on "A histone acetylation switch regulates H2A.Z deposition by the SWR-C remodeling enzyme".

    PubMed

    Wang, Feng; Ranjan, Anand; Wei, Debbie; Wu, Carl

    2016-07-22

    Watanabe et al (Reports, 12 April 2013, p. 195) study the yeast SWR1/SWR-C complex responsible for depositing the histone variant H2A.Z by replacing nucleosomal H2A with H2A.Z. They report that reversal of H2A.Z replacement is mediated by SWR1 and related INO80 on an H2A.Z nucleosome carrying H3K56Q. Using multiple assays and reaction conditions, we find no evidence of such reversal of H2A.Z exchange. PMID:27463665

  11. Effect of Annealing on Microstructure and Tensile Properties of 5052/AZ31/5052 Clad Sheets

    NASA Astrophysics Data System (ADS)

    Nie, Huihui; Liang, Wei; Chi, Chengzhong; Li, Xianrong; Fan, Haiwei; Yang, Fuqian

    2016-05-01

    Three-layered 5052Al/AZ31Mg/5052Al (5052/AZ31/5052) clad sheets were fabricated by four-pass rolling and annealed under different conditions. Under the optimal annealing condition, homogeneous and equiaxial grains with an average AZ31 grain size of 5.24 µm were obtained and the maximum values of ultimate tensile strength and elongation of the clad sheet reached 230 MPa and 18%, respectively. Electron backscatter diffraction analysis showed that the AZ31 layer had a typical rolling texture with its c-axis parallel to the normal direction. The fraction of low-angle grain boundaries in the 5052 layer was nearly four times more than that in the AZ31 layer because of different deformation extent and recrystallization driving forces. The textures of Al3Mg2 and Mg17Al12 were similar to that of 5052 because of the deformation coordination during the rolling and recrystallization process. The orientation relationship between Mg17Al12 and AZ31 seemed to be (110) Mg17Al12//(10-11) AZ31.

  12. Crystal structures of heterotypic nucleosomes containing histones H2A.Z and H2A

    PubMed Central

    Horikoshi, Naoki; Arimura, Yasuhiro; Taguchi, Hiroyuki; Kurumizaka, Hitoshi

    2016-01-01

    H2A.Z is incorporated into nucleosomes located around transcription start sites and functions as an epigenetic regulator for the transcription of certain genes. During transcriptional regulation, the heterotypic H2A.Z/H2A nucleosome containing one each of H2A.Z and H2A is formed. However, previous homotypic H2A.Z nucleosome structures suggested that the L1 loop region of H2A.Z would sterically clash with the corresponding region of canonical H2A in the heterotypic nucleosome. To resolve this issue, we determined the crystal structures of heterotypic H2A.Z/H2A nucleosomes. In the H2A.Z/H2A nucleosome structure, the H2A.Z L1 loop structure was drastically altered without any structural changes of the canonical H2A L1 loop, thus avoiding the steric clash. Unexpectedly, the heterotypic H2A.Z/H2A nucleosome is more stable than the homotypic H2A.Z nucleosome. These data suggested that the flexible character of the H2A.Z L1 loop plays an essential role in forming the stable heterotypic H2A.Z/H2A nucleosome. PMID:27358293

  13. Corrosion resistance of biodegradable polymeric layer-by-layer coatings on magnesium alloy AZ31

    NASA Astrophysics Data System (ADS)

    Cui, Lan-Yue; Zeng, Rong-Chang; Zhu, Xiao-Xiao; Pang, Ting-Ting; Li, Shuo-Qi; Zhang, Fen

    2016-06-01

    Biocompatible polyelectrolyte multilayers (PEMs) and polysiloxane hybrid coatings were prepared to improve the corrosion resistance of biodegradable Mg alloy AZ31. The PEMs, which contained alternating poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH), were first self-assembled on the surface of the AZ31 alloy substrate via electrostatic interactions, designated as (PAH/PSS)5/AZ31. Then, the (PAH/PSS)5/AZ31 samples were dipped into a methyltrimethoxysilane (MTMS) solution to fabricate the PMTMS films, designated as PMTMS/(PAH/PSS)5/AZ31. The surface morphologies, microstructures and chemical compositions of the films were investigated by FE-SEM, FTIR, XRD and XPS. Potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution measurements demonstrated that the PMTMS/(PAH/PSS)5/AZ31 composite film significantly enhanced the corrosion resistance of the AZ31 alloy in Hank's balanced salt solution (HBSS). The PAH and PSS films effectively improved the deposition of Ca-P compounds including Ca3(PO4)2 and hydroxyapatite (HA). Moreover, the corrosion mechanism of the composite coating was discussed. These coatings could be an alternative candidate coating for biodegradable Mg alloys.

  14. Mexico City

    Atmospheric Science Data Center

    2013-04-18

    ... Two small brighter patches within the hazy area indicate low fog. In the left-hand panel, the city basin appears significantly clearer, but ... very high altitudes, in contrast to the low-lying haze and fog near Mexico City. When the stereo retrieval determines that a location is ...

  15. Atypical Cities

    ERIC Educational Resources Information Center

    DiJulio, Betsy

    2011-01-01

    In this creative challenge, Surrealism and one-point perspective combine to produce images that not only go "beyond the real" but also beyond the ubiquitous "imaginary city" assignment often used to teach one-point perspective. Perhaps the difference is that in the "atypical cities challenge," an understanding of one-point perspective is a means…

  16. City Play.

    ERIC Educational Resources Information Center

    Dargan, Amanda; Zeitlin, Steve

    2000-01-01

    Today, fewer city blocks preserve the confidence of lifestyle and urban geography that sustain traditional games and outdoor play. Large groups of children choosing sides and organizing Red Rover games are no longer commonplace. Teachers must encourage free play; urban planners must build cities that are safe play havens. (MLH)

  17. Project W-211 Initial Tank Retrieval Systems (ITRS) Description of Operations for 241-AZ-102

    SciTech Connect

    BRIGGS, S.R.

    2000-02-25

    The primary purpose of the Initial Tank Retrieval Systems (ITRS) is to provide systems for retrieval of radioactive wastes stored in underground double-shell tanks (DSTs) for transfer to alternate storage, evaporation, pretreatment or treatment, while concurrently reducing risks associated with safety watch list and other DSTs. This Description of Operation (DOO) defines the control philosophy for the waste retrieval system for Tank 241-AZ-102 (AZ-102). This DOO provides a basis for the detailed design of the Project W-211 Retrieval Control System (RCS) for AZ-102 and also establishes test criteria for the RCS.

  18. Influence of Aluminum Content on Grain Refinement and Strength of AZ31 Magnesium GTA Weld Metal

    SciTech Connect

    Babu, N. Kishore; Cross, Carl E.

    2012-06-28

    The goal is to characterize the effect of Al content on AZ31 weld metal, the grain size and strength, and examine role of Al on grain refinement. The approach is to systematically vary the aluminum content of AZ31 weld metal, Measure average grain size in weld metal, and Measure cross-weld tensile properties and hardness. Conclusions are that: (1) increased Al content in AZ31 weld metal results in grain refinement Reason: higher undercooling during solidification; (2) weld metal grain refinement resulted in increased strength & hardness Reason: grain boundary strengthening; and (3) weld metal strength can be raised to wrought base metal levels.

  19. Chemical speciation of PM2.5 and PM10 in south Phoenix, AZ, USA.

    PubMed

    Upadhyay, Nabin; Clements, Andrea; Fraser, Matthew; Herckes, Pierre

    2011-03-01

    Phoenix, AZ, experiences high particulate matter (PM) episodes, especially in the wintertime. The spatial variation of the PM concentrations and resulting differences in exposure is of particular concern. In this study, PM2.s (PM with aerodynamic diameter <2.5 microm) and PM10 (PM with aerodynamic diameter <10 microm) samples were collected simultaneously from the east and west sides of South Phoenix and at a control site in Tempe and analyzed for trace elements and bulk elemental and organic carbon. Measurements showed that although PM2.5 concentrations had similar trends in temporal scale across all sites, concentrations of PM10 did not. The difference in PM10 concentrations and fluctuation across the three sites suggest effects of a local soil source as evidenced by high concentrations of Al, Ca, and Fe in PM10. K and anthropogenic elements (e.g., Cu, Pb, and Zn) in PM2.5 samples on January 1 were strikingly high, suggesting the influence of New Year's fireworks. Concentrations of toxic elements (e.g., Pb) in the study presented here are not different from similar studies in other U.S. cities. Application of principal component analysis indicated two broad categories of emission sources--soil and combustion--together accounting for 80 and 90% of variance, respectively, in PM2.5 and PM10. The soil and combustion components explained approximately 60 and 30% of the variance in PM10, respectively, whereas combustion sources dominated PM2.5 (>50% variance). Many elements associated with anthropogenic sources were highly enriched, with enrichment factors in PM2.5 an order of magnitude higher than in PM10 relative to surface soil composition in the study area.

  20. The Histone Chaperones FACT and Spt6 Restrict H2A.Z from Intragenic Locations

    PubMed Central

    Jeronimo, Célia; Watanabe, Shinya; Kaplan, Craig D.; Peterson, Craig L.; Robert, François

    2015-01-01

    SUMMARY H2A.Z is a highly conserved histone variant involved in several key nuclear processes. It is incorporated into promoters by SWR-C-related chromatin remodeling complexes, but whether it is also actively excluded from non-promoter regions is not clear. Here, we provide genomic and biochemical evidence that RNA polymerase II (RNAPII) elongation-associated histone chaperones FACT and Spt6 both contribute to restricting H2A.Z from intragenic regions. In the absence of FACT or Spt6, the lack of efficient nucleosome reassembly coupled to pervasive incorporation of H2A.Z by mislocalized SWR-C alters chromatin composition and contributes to cryptic initiation. Thus, chaperone-mediated H2A.Z confinement is crucial for restricting the chromatin signature of gene promoters, which otherwise may license or promote cryptic transcription. PMID:25959393

  1. Operational test procedure 241-AZ-101 waste tank color video camera system

    SciTech Connect

    Robinson, R.S.

    1996-10-30

    The purpose of this procedure is to provide a documented means of verifying that all of the functional components of the 241-AZ- 101 Waste Tank Video Camera System operate properly before and after installation.

  2. H2A.Z: a molecular rheostat for transcriptional control

    PubMed Central

    Subramanian*, Vidya; Fields*, Paul A.

    2015-01-01

    The replacement of nucleosomal H2A with the histone variant H2A.Z is critical for regulating DNA-mediated processes across eukaryotes and for early development of multicellular organisms. How this variant performs these seemingly diverse roles has remained largely enigmatic. Here, we discuss recent mechanistic insights that have begun to reveal how H2A.Z functions as a molecular rheostat for gene control. We focus on specific examples in metazoans as a model for understanding how H2A.Z integrates information from histone post-translational modifications, other histone variants, and transcription factors (TFs) to regulate proper induction of gene expression programs in response to cellular cues. Finally, we propose a general model of how H2A.Z incorporation regulates chromatin states in diverse processes. PMID:25705384

  3. Dry Sliding Wear Properties of AZ31-Mg2Si Magnesium Matrix Composites

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Wang, De; Fu, Yuan; Zhang, Li; Wang, Qudong

    2016-10-01

    AZ31-Mg2Si in situ composites were prepared from AZ31 Mg alloy and Si particles by a gravity casting method. Several parameters, such as Si content, normal load, and environmental temperature, were varied in order to study their effects on the composite dry sliding wear properties. Tensile properties and hardness of the composites were also investigated. The obtained results showed that the wear resistance, yield strength, and hardness of the AZ31-Mg2Si composites increased with size and quantity of the Mg2Si phase. However, when the environmental temperature increased from 25 to 190 °C, the composite wear resistance and ultimate tensile strength gradually decreased due to softening of the AZ31 matrix.

  4. 75 FR 49526 - Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Register on November 17, 2009 (74 FR 59249). At the request of the petitioners, the Department reviewed the... Employment and Training Administration Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor, Inc., Technical Information Center, Woburn, MA; Amended Certification...

  5. Dry Sliding Wear Properties of AZ31-Mg2Si Magnesium Matrix Composites

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Wang, De; Fu, Yuan; Zhang, Li; Wang, Qudong

    2016-08-01

    AZ31-Mg2Si in situ composites were prepared from AZ31 Mg alloy and Si particles by a gravity casting method. Several parameters, such as Si content, normal load, and environmental temperature, were varied in order to study their effects on the composite dry sliding wear properties. Tensile properties and hardness of the composites were also investigated. The obtained results showed that the wear resistance, yield strength, and hardness of the AZ31-Mg2Si composites increased with size and quantity of the Mg2Si phase. However, when the environmental temperature increased from 25 to 190 °C, the composite wear resistance and ultimate tensile strength gradually decreased due to softening of the AZ31 matrix.

  6. 77 FR 20356 - Foreign-Trade Zone 277-Western Maricopa County, AZ; Application for Manufacturing Authority...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-04

    ... Manufacturing Authority; Suntech Arizona, Inc., (Solar Panel Manufacturing), Goodyear, AZ An application has..., Inc., grantee of FTZ 277, requesting manufacturing authority on behalf of Suntech Arizona, Inc... foreign inputs that become scrap or waste during manufacturing. FTZ designation would further...

  7. Texture Evolution of Single-Pass Hot-Rolled 5052/AZ31/5052 Clad Sheets

    NASA Astrophysics Data System (ADS)

    Nie, Huihui; Liang, Wei; Yang, Fuqian; Zheng, Liuwei; Li, Xianrong; Fan, Haiwei

    2016-08-01

    Three-layered 5052/AZ31/5052 clad sheets with maximum rolling reductions of 33% and 48% were prepared, using single-pass hot rolling followed by thermal annealing at 200°C for 1 h. The evolutions of microstructures and textures were analyzed. The experimental results show that the AZ31 layer exhibited a typical deformation microstructure with rolling-induced twins. The AZ31 layer with the 33% rolling reduction possessed a texture with the basal pole tilting about 35° away from normal direction to transverse direction and the majority of twins consists of {10 bar{1} 1}-{10 bar{1} 2} double twins and {10 bar{1} 2} tensile twins. The AZ31 layer with the 48% rolling reduction possessed a typical basal texture because {10 bar{1} 1} compression twins were activated by c-axis strain to compete with the tensile twins. No intermetallics were observed after annealing, and recrystallization occurred preferentially at the interface between AZ31 and 5052. The typical rolling texture of the 5052 layer disappeared, and the stable {001} <110> rotation cube component was dominant. The tensile test of the rolled three-layered 5052/AZ31/5052 clad sheets was performed. The tensile experimental results show that the annealed clad sheets with 33% rolling reduction and smaller degree of recrystallization have the largest elongation of 22.5% and larger ultimate tensile strength (UTS) than the annealed clad sheets with 48% rolling reduction.

  8. Characterization of AZ31 magnesium alloy by duplex process combining laser surface melting and plasma electrolytic oxidation

    NASA Astrophysics Data System (ADS)

    Liu, Cancan; Liang, Jun; Zhou, Jiansong; Li, Qingbiao; Wang, Lingqian

    2016-09-01

    Top ceramic coatings were fabricated on the laser surface melting (LSM) modified AZ31 alloy by plasma electrolytic oxidation (PEO) in a phosphate electrolyte. The effect of LSM treatment on the microstructure and corrosion behavior of the bare and PEO treated AZ31 alloy was evaluated. Results showed that LSM treatment produced a homogeneous modified layer with redistributed intermetallic compounds, resulting in enhanced corrosion resistance of AZ31 alloy. The LSM treatment had no obvious influence on the surface and cross-sectional microstructures of the PEO coatings on AZ31 alloy. Besides, MgO was the main constituent for PEO coatings, regardless of LSM pretreatment. However, the long-term corrosion properties of the PEO coated AZ31 alloy with LSM pretreatment revealed large enhancement. Based on the analysis of microstructure and corrosion property, the corrosion mechanisms of the PEO and LSM-PEO coated AZ31 alloy were proposed.

  9. Bioactive benzofuran derivatives: moracins A-Z in medicinal chemistry.

    PubMed

    Naik, Ravi; Harmalkar, Dipesh S; Xu, Xuezhen; Jang, Kyusic; Lee, Kyeong

    2015-01-27

    Benzofuran heterocycles are fundamental structural units in a variety of biologically active natural products as well as synthetic materials. Over the time, benzofuran derivatives have attracted many researchers due to the broad scope of their biological activity, which include anticancer, antimicrobial, immunomodulatory, antioxidant and anti-inflammatory properties. Egonol, homoegonol and moracin families are biologically active natural products containing benzofuran heterocycle as basic structural units. This paper focuses on the moracin family (moracin A to Z). Morus, a genus of flowering plants in the family Moraceae, comprises 10-16 species of deciduous trees commonly known as mulberries. The root bark, stem bark and leaves of Morus alba, M. lhou, Morus macroura are the main sources for arylbenzofuran derivatives including the moracins. A large volume of research has been carried out on moracins and their derivatives, which has shown the pharmacological importance of this benzofuran heterocyclic nucleus. In this mini-review, we attempt to highlight the importance of moracins, as they have been a major source for drug development. Herein, we also summarize the current state of the art concerning the synthesis and medicinal use of moracins A-Z.

  10. Fine particulate chemical composition and light extinction at Meadview, AZ

    SciTech Connect

    Delbert J. Eatough; Wenxuan Cui; Jeffery Hull; Robert J. Farber

    2006-12-15

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr daynight samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was {+-} 0.6 {mu}g/m{sup 3} organic material, {+-} 0.3 {mu}g/m{sup 3} ammonium sulfate, and {+-} 0.07 {mu}g/m{sup 3} ammonium nitrate. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides sources in the region indicate that the major anthropogenic contributors to light extinction were from the Los Angeles, CA, and Las Vegas, NV, urban areas. Mohave Power Project associated secondary sulfate was a negligible contributor to light extinction. 49 refs., 12 figs., 7 tabs.

  11. Dynamic behavior and constitutive modeling of magnesium alloys AZ91D and AZ31B under high strain rate compressive loading

    NASA Astrophysics Data System (ADS)

    Xiao, Jing; Ahmad, Iram Raza; Shu, D. W.

    2014-03-01

    The dynamic stress-strain characteristics of magnesium alloys have not been sufficiently studied experimentally. Thus, the present work investigated compressive dynamic stress-strain characteristics of two representative magnesium alloys: AZ91D and AZ31B at high strain rates and elevated temperatures. In order to use the stress-strain characteristics in numerical simulations to predict the impact response of components, the stress-strain characteristics must be modeled. The most common approach is to use accepted constitutive laws. The results from the experimental study of the response of magnesium alloys AZ91D and AZ31B under dynamic compressive loading, at different strain rates and elevated temperatures are presented here. Johnson-Cook model was used to best fit the experimental data. The material parameters required by the model were obtained and the resultant stress-strain curves of the two alloys for each testing condition were plotted. It is found that the dynamic stress-strain relationship of both magnesium alloys are strain rate and temperature dependent and can be described reasonably well at high strain rates and room temperature by Johnson-Cook model except at very low strains. This might be due to the fact that the strain rate is not strictly constant in the early stage of deformation.

  12. Electrochemical characterization and in-vitro bio-assessment of AZ31B and AZ91E alloys as biodegradable implant materials.

    PubMed

    Ur Rahman, Zia; Pompa, Luis; Haider, Waseem

    2015-08-01

    The degradation of magnesium alloys, AZ31B and AZ91E, are under review due to a their ability to degrade under physiological conditions and successively yield an oxidized biocompatible by-product which can safely be absorbed by the body. By exploiting the biodegradability of magnesium alloys, the prospects of developing an unprecedented class of implant are at hand. To do so however, the rate of corrosion of the alloys must be modified in order to better suit physiological conditions. Therefore, anodization was carried out on AZ31B and AZ91E specimens to alter the surface chemistry to reduce the corrosion rates and improve biocompatibility. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle meter, were used to characterize and compare the surfaces of untreated and anodized magnesium alloys. Corrosion behavior was evaluated by electrochemical tests using potentiodynamic polarization and electrochemical impedance spectroscopy, to verify changes in corrosion rates as a result of anodization. Finally, a bio-assessment using MTS assays and fluorescent microscopy were carried out to ensure that the anodization process had no compromise on the biocompatibility of the magnesium alloys. The study indicated that the anodization process did alter the surface chemistry of the alloys, yielding slower corrosion rates, while causing no adverse effects in regards to biocompatibility.

  13. City 2020+

    NASA Astrophysics Data System (ADS)

    Schneider, C.; Buttstädt, M.; Merbitz, H.; Sachsen, T.; Ketzler, G.; Michael, S.; Klemme, M.; Dott, W.; Selle, K.; Hofmeister, H.

    2010-09-01

    This research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the City of Aachen as a case study. CITY 2020+ develops scenarios, options and tools for planning and developing sustainable future city structures. We investigate how urban environment, political structure and residential behavior can best be adapted, with attention to the interactions among structural, political, and sociological configurations and with their consequences on human health. Demographers project that in the EU-25-States by 2050, approximately 30% of the population will be over age 65. Also by 2050, average tem¬peratures are projected to rise by 1 to 2 K. Combined, Europe can expect enhanced thermal stress and higher levels of particulate matter. CITY 2020+ amongst other sub-projects includes research project dealing with (1) a micro-scale assessment of blockages to low-level cold-air drainage flow into the city centre by vegetation and building structures, (2) a detailed analysis of the change of probability density functions related to the occurrence of heat waves during summer and the spatial and temporal structure of the urban heat island (UHI) (3) a meso-scale analysis of particulate matter (PM) concentrations depending on topography, local meteorological conditions and synoptic-scale weather patterns. First results will be presented specifically from sub-projects related to vegetation barriers within cold air drainage, the assessment of the UHI and the temporal and spatial pattern of PM loadings in the city centre. The analysis of the cold air drainage flow is investigated in two consecutive years with a clearing of vegetation stands in the beginning of the second year early in 2010. The spatial pattern of the UHI and its possible enhancement by climate change is addressed employing a unique setup using GPS devices and temperature probes fixed to

  14. City Geology.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    This article provides information on the evolution of the building material, concrete, and suggests hands-on activities that allow students to experience concrete's qualities, test the heat absorbency of various ground surface materials, discover how an area's geology changes, and search for city fossils. A reproducible activity sheet is included.…

  15. Histone H2A.Z subunit exchange controls consolidation of recent and remote memory.

    PubMed

    Zovkic, Iva B; Paulukaitis, Brynna S; Day, Jeremy J; Etikala, Deepa M; Sweatt, J David

    2014-11-27

    Memory formation is a multi-stage process that initially requires cellular consolidation in the hippocampus, after which memories are downloaded to the cortex for maintenance, in a process termed systems consolidation. Epigenetic mechanisms regulate both types of consolidation, but histone variant exchange, in which canonical histones are replaced with their variant counterparts, is an entire branch of epigenetics that has received limited attention in the brain and has never, to our knowledge, been studied in relation to cognitive function. Here we show that histone H2A.Z, a variant of histone H2A, is actively exchanged in response to fear conditioning in the hippocampus and the cortex, where it mediates gene expression and restrains the formation of recent and remote memory. Our data provide evidence for H2A.Z involvement in cognitive function and specifically implicate H2A.Z as a negative regulator of hippocampal consolidation and systems consolidation, probably through downstream effects on gene expression. Moreover, alterations in H2A.Z binding at later stages of systems consolidation suggest that this histone has the capacity to mediate stable molecular modifications required for memory retention. Overall, our data introduce histone variant exchange as a novel mechanism contributing to the molecular basis of cognitive function and implicate H2A.Z as a potential therapeutic target for memory disorders. PMID:25219850

  16. Fine particulate chemical composition and light extinction at Meadview, AZ.

    PubMed

    Eatough, Delbert J; Cui, Wenxuan; Hull, Jeffery; Farber, Robert J

    2006-12-01

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr day-night samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was +/- 0.6 microg/m3 organic material, +/- 0.3 microg/m3 ammonium sulfate, and +/- 0.07 microg/m3 ammonium nitrate. Data were also available on fine particulate crustal material, fine and coarse particulate mass from the Interagency Monitoring of Protected Visual Environments sampling system, and relative humidity (RH), light absorption, particle scattering, and light extinction measurements from Project MOHAVE. An extinction budget was obtained using mass scattering coefficients estimated from particle size distribution data. Literature data were used to estimate the change in the mass scattering coefficients for the measured species as a function of RH and for the absorption of light by elemental carbon. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. During periods of highest light extinction, contributions from fine particulate organic material, sulfate, and light-absorbing carbon dominated the extinction of light by particles. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides

  17. Fine particulate chemical composition and light extinction at Meadview, AZ.

    PubMed

    Eatough, Delbert J; Cui, Wenxuan; Hull, Jeffery; Farber, Robert J

    2006-12-01

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr day-night samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was +/- 0.6 microg/m3 organic material, +/- 0.3 microg/m3 ammonium sulfate, and +/- 0.07 microg/m3 ammonium nitrate. Data were also available on fine particulate crustal material, fine and coarse particulate mass from the Interagency Monitoring of Protected Visual Environments sampling system, and relative humidity (RH), light absorption, particle scattering, and light extinction measurements from Project MOHAVE. An extinction budget was obtained using mass scattering coefficients estimated from particle size distribution data. Literature data were used to estimate the change in the mass scattering coefficients for the measured species as a function of RH and for the absorption of light by elemental carbon. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. During periods of highest light extinction, contributions from fine particulate organic material, sulfate, and light-absorbing carbon dominated the extinction of light by particles. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides

  18. Formation of intermetallic compound coating on magnesium AZ91 cast alloy

    NASA Astrophysics Data System (ADS)

    Zhu, Tianping; Gao, Wei

    2009-08-01

    This study describes an intermetallic compound coating formed on AZ91 Mg cast alloy. The Al sputtered on AZ91 cast alloy reacted with substrate during a short period of heat treatment at 435°C, resulting in the formation of a continuous intermetallic compound layer. The short period treatment has the advantage of minimizing the negative effect on the microstructure of substrate and the mechanical properties, comparing with the reported diffusion coatings. DSC measurement and examination on the cross-section of Al sputtered samples show that local melting occurred along the Al/substrate interface at the temperature range between 430~435°C. The formation mechanism of intermetallic compound coating is proposed in terms of the local melting at Al/substrate interface. The salt water immersion test showed significant improvement in corrosion resistance of the intermetallic compound coated AZ91 cast alloy compared with the as-cast alloys.

  19. Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan

    SciTech Connect

    TEMPLETON, A.M.

    2000-03-06

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification. Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications.

  20. Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan

    SciTech Connect

    TEMPLETON, A.M.

    2000-04-10

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification. Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications.

  1. Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan

    SciTech Connect

    TEMPLETON, A.M.

    2000-01-31

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications.

  2. Ultrasonic Spot Welding of AZ31B to Galvanized Mild Steel

    SciTech Connect

    Pan, Dr. Tsung-Yu; Franklin, Teresa; Pan, Professor Jwo; Brown, Elliot; Santella, Michael L

    2010-01-01

    Ultrasonic spot welds were made between sheets of 0.8-mm-thick hot-dip-galvanized mild steel and 1.6-mm-thick AZ31B-H24. Lap-shear strengths of 3.0-4.2 kN were achieved with weld times of 0.3-1.2 s. Failure to achieve strong bonding of joints where the Zn coating was removed from the steel surface indicate that Zn is essential to the bonding mechanism. Microstructure characterization and microchemical analysis indicated temperatures at the AZ31-steel interfaces reached at least 344 C in less than 0.3 s. The elevated temperature conditions promoted annealing of the AZ31-H24 metal and chemical reactions between it and the Zn coating.

  3. Electrodeposition of high corrosion resistance Cu/Ni-P coating on AZ91D magnesium alloy

    NASA Astrophysics Data System (ADS)

    Zhang, Shan; Cao, Fahe; Chang, Linrong; Zheng, JunJun; Zhang, Zhao; Zhang, Jianqing; Cao, Chunan

    2011-08-01

    High corrosion resistance Cu/Ni-P coatings were electrodeposited on AZ91D magnesium alloy via suitable pretreatments, such as one-step acid pickling-activation, once zinc immersion and environment-friendly electroplated copper as the protective under-layer, which made Ni-P deposit on AZ91D Mg alloy in acid plating baths successfully. The pH value and current density for Ni-P electrodeposition were optimized to obtain high corrosion resistance. With increasing the phosphorous content of the Ni-P coatings, the deposits were found to gradually transform to amorphous structure and the corrosion resistance increased synchronously. The anticorrosion ability of AZ91D Mg alloy was greatly improved by the amorphous Ni-P deposits, which was investigated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The corrosion current density ( Icorr) of the coated Mg alloy substrate is about two orders of magnitude less than that of the uncoated.

  4. 75 FR 61660 - Proposed Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ... Class E airspace designated as an extension to a Class D or E surface area at Flagstaff Pulliam Airport... eliminates the need for Class E airspace designated as an extension to a Class D or E surface area, and... surface area. * * * * * AWP AZ E4 Flagstaff, AZ Paragraph 6005 Class E airspace areas extending...

  5. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  6. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  7. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  8. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  9. H2A.Z.1 mono-ubiquitylation antagonizes BRD2 to maintain poised chromatin in ESCs

    PubMed Central

    Surface, Lauren E.; Fields, Paul A.; Subramanian, Vidya; Behmer, Russell; Udeshi, Namrata; Peach, Sally E.; Jaffe, Jacob D.; Boyer, Laurie A.

    2016-01-01

    SUMMARY Histone variant H2A.Z occupies the promoters of active and poised, bivalent genes in ESCs to regulate developmental programs, yet how it contributes to these contrasting states is poorly understood. Here, we investigate the function of H2A.Z.1 mono-ubiquitylation (H2A.Z.1ub) by mutation of the PRC1 target residues (H2A.Z.1K3R3). We show that H2A.Z.1K3R3 is properly incorporated at target promoters in murine ESCs (mESCs), however, loss of mono-ubiquitylation leads to de-repression of bivalent genes, loss of Polycomb binding, and to faulty lineage commitment. Using quantitative proteomics, we find that tandem bromodomain proteins, including the BET family member Brd2, are enriched in H2A.Z.1 chromatin. We further show that Brd2 is gained at de-repressed promoters in H2A.Z.1K3R3 mESCs whereas Brd2 inhibition restores gene silencing at these sites. Together, our study reveals an antagonistic relationship between H2A.Z.1ub and Brd2 to regulate the transcriptional balance at bivalent genes to enable proper execution of developmental programs. PMID:26804911

  10. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  11. Corrosion and mechanical performance of AZ91 exposed to simulated inflammatory conditions.

    PubMed

    Brooks, Emily K; Der, Stephanie; Ehrensberger, Mark T

    2016-03-01

    Magnesium (Mg) and its alloys, including Mg-9%Al-1%Zn (AZ91), are biodegradable metals with potential use as temporary orthopedic implants. Invasive orthopedic procedures can provoke an inflammatory response that produces hydrogen peroxide (H2O2) and an acidic environment near the implant. This study assessed the influence of inflammation on both the corrosion and mechanical properties of AZ91. The AZ91 samples in the inflammatory protocol were immersed for three days in a complex biologically relevant electrolyte (AMEM culture media) that contained serum proteins (FBS), 150 mM of H2O2, and was titrated to a pH of 5. The control protocol immersed AZ91 samples in the same biologically relevant electrolyte (AMEM & FBS) but without H2O2 and the acid titration. After 3 days all samples were switched into fresh AMEM & FBS for an additional 3-day immersion. During the initial immersion, inflammatory protocol samples showed increased corrosion rate determined by mass loss testing, increased Mg and Al ion released to solution, and a completely corroded surface morphology as compared to the control protocol. Although corrosion in both protocols slowed once the test electrolyte solution was replaced at 3 days, the samples originally exposed to the simulated inflammatory conditions continued to display enhanced corrosion rates as compared to the control protocol. These lingering effects may indicate the initial inflammatory corrosion processes modified components of the surface oxide and corrosion film or initiated aggressive localized processes that subsequently left the interface more vulnerable to continued enhanced corrosion. The electrochemical properties of the interfaces were also evaluated by EIS, which found that the corrosion characteristics of the AZ91 samples were potentially influenced by the role of intermediate adsorption layer processes. The increased corrosion observed for the inflammatory protocol did not affect the flexural mechanical properties of the AZ91

  12. Corrosion and mechanical performance of AZ91 exposed to simulated inflammatory conditions.

    PubMed

    Brooks, Emily K; Der, Stephanie; Ehrensberger, Mark T

    2016-03-01

    Magnesium (Mg) and its alloys, including Mg-9%Al-1%Zn (AZ91), are biodegradable metals with potential use as temporary orthopedic implants. Invasive orthopedic procedures can provoke an inflammatory response that produces hydrogen peroxide (H2O2) and an acidic environment near the implant. This study assessed the influence of inflammation on both the corrosion and mechanical properties of AZ91. The AZ91 samples in the inflammatory protocol were immersed for three days in a complex biologically relevant electrolyte (AMEM culture media) that contained serum proteins (FBS), 150 mM of H2O2, and was titrated to a pH of 5. The control protocol immersed AZ91 samples in the same biologically relevant electrolyte (AMEM & FBS) but without H2O2 and the acid titration. After 3 days all samples were switched into fresh AMEM & FBS for an additional 3-day immersion. During the initial immersion, inflammatory protocol samples showed increased corrosion rate determined by mass loss testing, increased Mg and Al ion released to solution, and a completely corroded surface morphology as compared to the control protocol. Although corrosion in both protocols slowed once the test electrolyte solution was replaced at 3 days, the samples originally exposed to the simulated inflammatory conditions continued to display enhanced corrosion rates as compared to the control protocol. These lingering effects may indicate the initial inflammatory corrosion processes modified components of the surface oxide and corrosion film or initiated aggressive localized processes that subsequently left the interface more vulnerable to continued enhanced corrosion. The electrochemical properties of the interfaces were also evaluated by EIS, which found that the corrosion characteristics of the AZ91 samples were potentially influenced by the role of intermediate adsorption layer processes. The increased corrosion observed for the inflammatory protocol did not affect the flexural mechanical properties of the AZ91

  13. Magma mixing in the San Francisco Volcanic Field, AZ

    NASA Astrophysics Data System (ADS)

    Bloomfield, Anne L.; Arculus, Richard J.

    1989-08-01

    A wide variety of rock types are present in the O'Leary Peak and Strawberry Crater volcanics of the Pliocene to Recent San Francisco Volcanic Field (SFVF), AZ. The O'Leary Peak flows range from andesite to rhyolite (56 72 wt % SiO2) and the Strawberry Crater flows range from basalt to dacite (49 64 wt % SiO2). Our interpretation of the chemical data is that both magma mixing and crustal melting are important in the genesis of the intermediate composition lavas of both suites. Observed chemical variations in major and trace elements can be modeled as binary mixtures between a crustal melt similar to the O'Leary dome rhyolite and two different mafic end-members. The mafic end-member of the Strawberry suite may be a primary mantle-derived melt. Similar basalts have also been erupted from many other vents in the SFVF. In the O'Leary Peak suite, the mafic end-member is an evolved (low Mg/(Mg+ Fe)) basalt that is chemically distinct from the Strawberry Crater and other vent basalts as it is richer in total Fe, TiO2, Al2O3, MnO, Na2O, K2O, and Zr and poorer in MgO, CaO, P2O5, Ni, Sc, Cr, and V. The derivative basalt probably results from fractional crystallization of the more primitive, vent basalt type of magma. This evolved basalt occurs as xenolithic (but originally magmatic) inclusions in the O'Leary domes and andesite porphyry flow. The most mafic xenolith may represent melt that mixed with the O'Leary dome rhyolite resulting in andesite preserved as other xenoliths, a pyroclastic unit (Qoap), porphyry flow (Qoaf) and dacite (Darton Dome) magmas. Thermal constraints on the capacity of a melt to assimilate (and melt) a volume of solid material require that melt mixing and not assimilation has produced the observed intermediate lavas at both Strawberry Crater and O'Leary Peak. Textures, petrography, and mineral chemistry support the magma mixing model. Some of the inclusions have quenched rims where in contact with the host. The intermediate rocks, including the

  14. CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101 & 241AZ-102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

    SciTech Connect

    DUNCAN JB; HUBER HJ

    2011-04-21

    This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-l0-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannah River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FBSR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-5.2.1-2010-001, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies Using

  15. 77 FR 62216 - Proposed Foreign-Trade Zone-Eloy, AZ Comment Period on New Evidence

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ..., requesting authority to establish a general-purpose FTZ at sites in Pinal County, Arizona (76 FR 30907, 05/27... Foreign-Trade Zones Board Proposed Foreign-Trade Zone--Eloy, AZ Comment Period on New Evidence On May 23... 15 CFR 400.27(d)(2)(v)(B)), the FTZ Board is now inviting public comment on new evidence submitted...

  16. 78 FR 72006 - Establishment of Class D Airspace and Class E Airspace; Laguna AAF, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-02

    ... Register a notice of proposed rulemaking (NPRM) to establish controlled airspace at Laguna AAF, AZ (78 FR... Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a regulatory evaluation... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR,...

  17. Study on fused/cast AZS refractories for deployment in vitrification of radioactive waste effluents

    NASA Astrophysics Data System (ADS)

    Sengupta, Pranesh; Mishra, R. K.; Soudamini, N.; Sen, D.; Mazumder, S.; Kaushik, C. P.; Ajithkumar, T. G.; Banerjee, K.

    2015-12-01

    'Fused/cast Al2O3-ZrO2-SiO2 (FC-AZS)' is being considered as 'glass contact refractory' within ceramic melters, to be used for nuclear waste immobilization. Microstructural analyses reveal random distributions of baddeleyite (ZrO2) within aluminosilicate (Al2SiO5) matrix. 27Al and 29Si NMR data suggest that within aluminosilicate matrix Al occurs in both 4- and 6-fold co-ordinations whereas Si prefers a 4-fold environment. Polydispersity of pores has been studied with small-angle neutron scattering (SANS) technique. Corrosion rates of FC-AZS within 6 M HNO3, simulated wastes (500 h exposure), and borosilicate melt (975 °C, 800 h exposure) are found to be 0.38 × 103 μmy-1, 0.13 × 103 μmy-1 and 4.75 × 103 μmy-1 respectively. A comparison of chemical interaction data clearly suggests that FC-AZS exhibits better chemical durability than AZC refractory (Al2O3-ZrO2-Cr2O3, also used for similar purpose). Thermal cycling studies indicate that FC-AZS retains structural integrity (including compressive strength and density) even up to 20 cycles.

  18. Arabidopsis meiotic crossover hotspots overlap with H2A.Z nucleosomes at gene promoters

    PubMed Central

    Choi, Kyuha; Zhao, Xiaohui; Kelly, Krystyna A.; Venn, Oliver; Higgins, James D.; Yelina, Nataliya E.; Hardcastle, Thomas J.; Ziolkowski, Piotr A.; Copenhaver, Gregory P.; Franklin, F. Chris H.; McVean, Gil; Henderson, Ian R.

    2013-01-01

    PRDM9 directs human meiotic crossover hotspots to intergenic sequence motifs, whereas budding yeast hotspots overlap low nucleosome density regions in gene promoters. To investigate hotspots in plants, which lack PRDM9, we used coalescent analysis of Arabidopsis genetic variation. Crossovers increase towards gene promoters and terminators, and hotspots are associated with active chromatin modifications, including H2A.Z, histone H3K4me3, low nucleosome density and low DNA methylation. Hotspot-enriched A-rich and CTT-repeat DNA motifs occur upstream and downstream of transcriptional start respectively. Crossovers are asymmetric around promoters and highest over CTT-motifs and H2A.Z-nucleosomes. Pollen-typing, segregation and cytogenetic analysis show decreased crossovers in the arp6 H2A.Z deposition mutant, at multiple scales. During meiosis H2A.Z and DMC1/RAD51 recombinases form overlapping chromosomal foci. As arp6 reduces DMC1/RAD51 foci, H2A.Z may promote formation or processing of meiotic DNA double-strand breaks. We propose that gene chromatin ancestrally designates hotspots within eukaryotes and PRDM9 is a derived state within vertebrates. PMID:24056716

  19. 76 FR 42155 - Arizona Disaster #AZ-00017 Declaration of Economic Injury

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... ADMINISTRATION Arizona Disaster AZ-00017 Declaration of Economic Injury AGENCY: U.S. Small Business... for the State of Arizona, dated 07/11/2011. Incident: Wallow Fire. Incident Period: 05/29/2011 and... disaster: Primary Counties: Apache. Contiguous Counties: Arizona: Graham, Greenlee, Navajo....

  20. 76 FR 8801 - Arizona Disaster #AZ-00015 Declaration of Economic Injury

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... ADMINISTRATION Arizona Disaster AZ-00015 Declaration of Economic Injury AGENCY: U.S. Small Business... for the State of Arizona, dated 02/07/2011. Incident: Rainfall, Flooding and Flash Flooding. Incident... determined to be adversely affected by the disaster: Primary Counties: Coconino. Contiguous Counties:...

  1. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.

    PubMed

    Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials.

  2. 78 FR 65370 - Notice of Inventory Completion: Pima County Office of the Medical Examiner, Tucson, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    .... ADDRESSES: Dr. Bruce Anderson, Forensic Anthropologist, PCOME, Tucson, AZ 85714, telephone (520) 243-8600... Office for forensic analysis. The Pinal County Medical Examiner, Dr Rebecca Hsu, transferred the remains to the Pima County Office of the Medical Examiner for examination by a forensic anthropologist....

  3. 75 FR 35504 - San Rafael Cattle Company; Habitat Conservation Plan; Santa Cruz County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... Fish and Wildlife Service San Rafael Cattle Company; Habitat Conservation Plan; Santa Cruz County, AZ AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of availability; Draft Low-Effect Habitat... habitat from specified actions conducted under the authority of the San Rafael Cattle Company. We...

  4. 78 FR 34558 - Modification of Class E Airspace; Clifton/Morenci, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... Clifton/Morenci, AZ (78 FR 18269). Interested parties were invited to participate in this rulemaking... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of... FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in 14 CFR...

  5. 76 FR 2000 - Modification of Class E Airspace; Show Low, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Register a notice of proposed rulemaking to amend controlled airspace at Show Low, AZ (75 FR 65255... a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979.... 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by reference in...

  6. 75 FR 63066 - Establishment of Class E Airspace; Clifton/Morenci, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-14

    ... establish controlled airspace at Clifton/Morenci, AZ (75 FR 44725). Interested parties were invited to... Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a... follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963...

  7. 76 FR 82113 - Amendment of Class E Airspace; Show Low, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... controlled airspace at Show Low, AZ (76 FR 64041). Interested parties were invited to participate in this... Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The...

  8. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.

    PubMed

    Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials. PMID:25686961

  9. Structural evaluation of thermocouple probes for 241-AZ-101 waste tank

    SciTech Connect

    Kanjilal, S.K.

    1994-12-06

    This document reports on the structural analysis of the thermocouple probe to be installed in 241-AZ-101 waste tank. The thermocouple probe is analyzed for normal pump mixing operation and potential earthquake induced loads required by the Hanford Site Design Criteria SDC-4.1.

  10. Validation of Airborne Visible-Infrared Imaging Spectrometer Data at Ray Mine, AZ

    NASA Technical Reports Server (NTRS)

    Lang, H.; Baloga, S.

    1999-01-01

    We validate 1997 Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) reflectance spectra covering 0.4 meu - 2.4 meu from a stable, flat mineralogically characterized man-made target at Ray Mine, AZ, the site for an EPA/NASA assessment of the utility of remote sensing for monitoring acid drainage from an active open pit mine.

  11. 241-AZ-101 Waste Tank Color Video Camera System Shop Acceptance Test Report

    SciTech Connect

    WERRY, S.M.

    2000-03-23

    This report includes shop acceptance test results. The test was performed prior to installation at tank AZ-101. Both the camera system and camera purge system were originally sought and procured as a part of initial waste retrieval project W-151.

  12. 78 FR 3027 - Notice of Temporary Closures of Public Lands in La Paz County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-15

    ...-10-05] Notice of Temporary Closures of Public Lands in La Paz County, AZ AGENCY: Bureau of Land... Lake Havasu Field Office in La Paz County, Arizona. This action is being taken to help ensure public... the La Paz County Emergency Medical Services and Fire, the Arizona Department of Public Safety, or...

  13. 76 FR 5398 - Notice of Temporary Closure of Selected Public Lands in La Paz County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ...-330-07-02] Notice of Temporary Closure of Selected Public Lands in La Paz County, AZ AGENCY: Bureau of... its administration in La Paz County, Arizona. This action is being taken to protect persons, property... under the guidance of the La Paz County Emergency Medical Services and Fire, or the Arizona...

  14. 78 FR 71641 - Notice of Realty Action: Direct Sale of Public Land in Graham County, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... Bureau of Land Management Notice of Realty Action: Direct Sale of Public Land in Graham County, AZ AGENCY... acres of public land in Graham County, Arizona, to Gilligan and Blanca Bowman (proponents) for not less... business hours. SUPPLEMENTARY INFORMATION: The following described parcel of public land in Graham...

  15. 77 FR 2242 - Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [MB Docket No. 08-85; RM-11427, RM-11517, RM-11518, RM-11519; DA 11- 2059] Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ, and Needles,...

  16. 75 FR 11939 - DNS Electronics, Chandler, AZ; Notice of Termination of Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration DNS Electronics, Chandler, AZ; Notice of Termination of Investigation... a petition filed on May 27, 2009, by three workers on behalf of workers of DNS Electronics,...

  17. 76 FR 14115 - Arizona Disaster #AZ-00015 Declaration of Economic Injury

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... ADMINISTRATION Arizona Disaster AZ-00015 Declaration of Economic Injury AGENCY: U.S. Small Business...) declaration for the State of Arizona, dated 02/07/2011. Incident: Rainfall, Flooding and Flash Flooding... Declaration for the State of Arizona, dated 02/07/2011 is hereby amended to include the following areas...

  18. 76 FR 45178 - Modification of Class D and E Airspace; Fort Huachuca, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... Register a notice of proposed rulemaking to modify controlled airspace at Fort Huachuca, AZ (76 FR 29179... 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p....

  19. 75 FR 5115 - Temporary Concession Contract for Lake Mead National Recreation Area, AZ/NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-01

    ... concession contract for Lake Mead National Recreation Area. SUMMARY: Pursuant to 36 CFR 51.24, public notice... National Park Service Temporary Concession Contract for Lake Mead National Recreation Area, AZ/NV AGENCY... the conduct of certain visitor services within Lake Mead National Recreation Area, Arizona and...

  20. Tank 241-AZ-101 steam bumping and settling Process Test report

    SciTech Connect

    Winkler, C.M.

    1995-12-04

    This report summarizes the process test in which the airlift circulators in Tank 241-AZ-101 were shutdown. The test was successful, in that no extreme temperature excursions occurred. Only general data was obtianed through the use of a gamma energy probe.

  1. Complete Genome Sequence of the Model Rhizosphere Strain Azospirillum brasilense Az39, Successfully Applied in Agriculture.

    PubMed

    Rivera, Diego; Revale, Santiago; Molina, Romina; Gualpa, José; Puente, Mariana; Maroniche, Guillermo; Paris, Gastón; Baker, David; Clavijo, Bernardo; McLay, Kirsten; Spaepen, Stijn; Perticari, Alejandro; Vazquez, Martín; Wisniewski-Dyé, Florence; Watkins, Chris; Martínez-Abarca, Francisco; Vanderleyden, Jos; Cassán, Fabricio

    2014-07-24

    We present the complete genome sequence of Azospirillum brasilense Az39, isolated from wheat roots in the central region of Argentina and used as inoculant in extensive and intensive agriculture during the last four decades. The genome consists of 7.39 Mb, distributed in six replicons: one chromosome, three chromids, and two plasmids.

  2. Learning Cities as Healthy Green Cities: Building Sustainable Opportunity Cities

    ERIC Educational Resources Information Center

    Kearns, Peter

    2012-01-01

    This paper discusses a new generation of learning cities we have called EcCoWell cities (Economy, Community, Well-being). The paper was prepared for the PASCAL International Exchanges (PIE) and is based on international experiences with PIE and developments in some cities. The paper argues for more holistic and integrated development so that…

  3. Electrophoretic Deposition of 3YSZ Coating on AZ91D Alloy Using Al and Ni-P Interlayers

    NASA Astrophysics Data System (ADS)

    Shahriari, A.; Aghajani, H.

    2016-10-01

    Electrophoretic deposition was used in order to apply the zirconia stabilized by 3 mol% Y2O3 onto the surface of the magnesium alloy AZ91D. Two different interlayers which were including aluminum layer and Ni-P layer were prepared between the AZ91D surface and YSZ coating and the effect of them on the quality of YSZ coating was investigated. The surface morphologies of the coatings were studied by scanning electron microscopy, and their compositions were determined by x-ray diffraction. The corrosion resistance of the coatings was evaluated by electrochemical impedance spectroscopy in 3.5% NaCl neutral solution. Also, the stability of coating was investigated by the Rockwell C indentation test. The results showed that the YSZ coating applied onto different interlayers on AZ91D improves the corrosion resistance of this alloy due to increase in charge-transfer resistance of the AZ91D surface. Also, the aluminum interlayer has a favorable effect on the densification of the coating by formation of aluminum oxide. Furthermore, the corrosion resistance of AZ91D that coated by YSZ and aluminum layer was improved compared to that of coated AZ91D with YSZ and Ni-P layer. The presence of interlayers can make the stability of the YSZ coating improved on the surface of AZ91D.

  4. Structural basis of H2A.Z recognition by SRCAP chromatin-remodeling subunit YL1.

    PubMed

    Liang, Xiaoping; Shan, Shan; Pan, Lu; Zhao, Jicheng; Ranjan, Anand; Wang, Feng; Zhang, Zhuqiang; Huang, Yingzi; Feng, Hanqiao; Wei, Debbie; Huang, Li; Liu, Xuehui; Zhong, Qiang; Lou, Jizhong; Li, Guohong; Wu, Carl; Zhou, Zheng

    2016-04-01

    Histone variant H2A.Z, a universal mark of dynamic nucleosomes flanking gene promoters and enhancers, is incorporated into chromatin by SRCAP (SWR1), an ATP-dependent, multicomponent chromatin-remodeling complex. The YL1 (Swc2) subunit of SRCAP (SWR1) plays an essential role in H2A.Z recognition, but how it achieves this has been unclear. Here, we report the crystal structure of the H2A.Z-binding domain of Drosophila melanogaster YL1 (dYL1-Z) in complex with an H2A.Z-H2B dimer at 1.9-Å resolution. The dYL1-Z domain adopts a new whip-like structure that wraps over H2A.Z-H2B, and preferential recognition is largely conferred by three residues in loop 2, the hyperacidic patch and the extended αC helix of H2A.Z. Importantly, this domain is essential for deposition of budding yeast H2A.Z in vivo and SRCAP (SWR1)-catalyzed histone H2A.Z replacement in vitro. Our studies distinguish YL1-Z from known H2A.Z chaperones and suggest a hierarchical mechanism based on increasing binding affinity facilitating H2A.Z transfer from SRCAP (SWR1) to the nucleosome. PMID:26974124

  5. Tank 241-AZ-101 criticality assessment resulting from pump jet mixing: Sludge mixing simulation

    SciTech Connect

    Onishi, Y.; Recknagle, K.

    1997-04-01

    Tank 241-AZ-101 (AZ-101) is one of 28 double-shell tanks located in the AZ farm in the Hanford Site`s 200 East Area. The tank contains a significant quantity of fissile materials, including an estimated 9.782 kg of plutonium. Before beginning jet pump mixing for mitigative purposes, the operations must be evaluated to demonstrate that they will be subcritical under both normal and credible abnormal conditions. The main objective of this study was to address a concern about whether two 300-hp pumps with four rotating 18.3-m/s (60-ft/s) jets can concentrate plutonium in their pump housings during mixer pump operation and cause a criticality. The three-dimensional simulation was performed with the time-varying TEMPEST code to determine how much the pump jet mixing of Tank AZ-101 will concentrate plutonium in the pump housing. The AZ-101 model predicted that the total amount of plutonium within the pump housing peaks at 75 g at 10 simulation seconds and decreases to less than 10 g at four minutes. The plutonium concentration in the entire pump housing peaks at 0.60 g/L at 10 simulation seconds and is reduced to below 0.1 g/L after four minutes. Since the minimum critical concentration of plutonium is 2.6 g/L, and the minimum critical plutonium mass under idealized plutonium-water conditions is 520 g, these predicted maximums in the pump housing are much lower than the minimum plutonium conditions needed to reach a criticality level. The initial plutonium maximum of 1.88 g/L still results in safety factor of 4.3 in the pump housing during the pump jet mixing operation.

  6. Key Functional Regions in the Histone Variant H2A.Z C-Terminal Docking Domain ▿

    PubMed Central

    Wang, Alice Y.; Aristizabal, Maria J.; Ryan, Colm; Krogan, Nevan J.; Kobor, Michael S.

    2011-01-01

    The incorporation of histone variants into nucleosomes represents one way of altering the chromatin structure to accommodate diverse functions. Histone variant H2A.Z has specific roles in gene regulation, heterochromatin boundary formation, and genomic integrity. The precise features required for H2A.Z to function and specify an identity different from canonical H2A remain to be fully explored. Analysis of the C-terminal docking domain of H2A.Z in Saccharomyces cerevisiae using epistatic miniarray profile (E-MAP) uncovered nuanced requirements of the H2A.Z C-terminal region for cell growth when additional genes were compromised. Moreover, the H2A.Z(1–114) truncation, lacking the last 20 amino acids of the protein, did not support regular H2A.Z functions, such as resistance to genotoxic stress, restriction of heterochromatin in its native context, GAL1 gene activation, and chromatin anchoring. The corresponding region of H2A could fully rescue the strong defects caused by loss of this functionally essential region in the C terminus of H2A.Z. Despite the dramatic reduction in function, the H2A.Z(1–114) truncation still bound the H2A.Z deposition complex SWR1-C, the histone chaperone Chz1, and histone H2B. These data are consistent with a model in which retaining the variant in chromatin after its deposition by SWR1-C is a crucial determinant of its function. PMID:21791612

  7. Oncogenic potential of histone-variant H2A.Z.1 and its regulatory role in cell cycle and epithelial-mesenchymal transition in liver cancer

    PubMed Central

    Eun, Jung Woo; Shen, Qingyu; Kim, Hyung Seok; Shin, Woo Chan; Ahn, Young Min; Park, Won Sang; Lee, Jung Young; Nam, Suk Woo

    2016-01-01

    H2A.Z is a highly conserved H2A variant, and two distinct H2A.Z isoforms, H2A.Z.1 and H2A.Z.2, have been identified as products of two non-allelic genes, H2AFZ and H2AFV. H2A.Z has been reported to be overexpressed in breast, prostate and bladder cancers, but most studies did not clearly distinguish between isoforms. One recent study reported a unique role for the H2A.Z isoform H2A.Z.2 as a driver of malignant melanoma. Here we first report that H2A.Z.1 plays a pivotal role in the liver tumorigenesis by selectively regulating key molecules in cell cycle and epithelial-mesenchymal transition (EMT). H2AFZ expression was significantly overexpressed in a large cohort of hepatocellular carcinoma (HCC) patients, and high expression of H2AFZ was significantly associated with their poor prognosis. H2A.Z.1 overexpression was demonstrated in a subset of human HCC and cell lines. H2A.Z.1 knockdown suppressed HCC cell growth by transcriptional deregulation of cell cycle proteins and caused apoptotic cell death of HCC cells. We also observed that H2A.Z.1 knockdown reduced the metastatic potential of HCC cells by selectively modulating epithelial-mesenchymal transition regulatory proteins such as E-cadherin and fibronectin. In addition, H2A.Z.1 knockdown reduced the in vivo tumor growth rate in a mouse xenograft model. In conclusion, our findings suggest the oncogenic potential of H2A.Z.1 in liver tumorigenesis and that it plays established role in accelerating cell cycle transition and EMT during hepatocarcinogenesis. This makes H2A.Z.1 a promising target in liver cancer therapy. PMID:26863632

  8. Clean Cities Fact Sheet

    SciTech Connect

    Not Available

    2004-01-01

    This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

  9. Respiratory Syncytial Virus Inhibitor AZ-27 Differentially Inhibits Different Polymerase Activities at the Promoter

    PubMed Central

    Noton, Sarah L.; Nagendra, Kartikeya; Dunn, Ewan F.; Mawhorter, Michael E.; Yu, Qin

    2015-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is the leading cause of pediatric respiratory disease. RSV has an RNA-dependent RNA polymerase that transcribes and replicates the viral negative-sense RNA genome. The large polymerase subunit (L) has multiple enzymatic activities, having the capability to synthesize RNA and add and methylate a cap on each of the viral mRNAs. Previous studies (H. Xiong et al., Bioorg Med Chem Lett, 23:6789–6793, 2013, http://dx.doi.org/10.1016/j.bmcl.2013.10.018; C. L. Tiong-Yip et al., Antimicrob Agents Chemother, 58:3867–3873, 2014, http://dx.doi.org/10.1128/AAC.02540-14) had identified a small-molecule inhibitor, AZ-27, that targets the L protein. In this study, we examined the effect of AZ-27 on different aspects of RSV polymerase activity. AZ-27 was found to inhibit equally both mRNA transcription and genome replication in cell-based minigenome assays, indicating that it inhibits a step common to both of these RNA synthesis processes. Analysis in an in vitro transcription run-on assay, containing RSV nucleocapsids, showed that AZ-27 inhibits synthesis of transcripts from the 3′ end of the genome to a greater extent than those from the 5′ end, indicating that it inhibits transcription initiation. Consistent with this finding, experiments that assayed polymerase activity on the promoter showed that AZ-27 inhibited transcription and replication initiation. The RSV polymerase also can utilize the promoter sequence to perform a back-priming reaction. Interestingly, addition of AZ-27 had no effect on the addition of up to three nucleotides by back-priming but inhibited further extension of the back-primed RNA. These data provide new information regarding the mechanism of inhibition by AZ-27. They also suggest that the RSV polymerase adopts different conformations to perform its different activities at the promoter. IMPORTANCE Currently, there are no effective antiviral drugs to treat RSV infection. The RSV polymerase is an

  10. The novel tankyrase inhibitor (AZ1366) enhances irinotecan activity in tumors that exhibit elevated tankyrase and irinotecan resistance

    PubMed Central

    Quackenbush, Kevin S.; Bagby, Stacey; Tai, Wai Meng; Messersmith, Wells A.; Schreiber, Anna; Greene, Justin; Kim, Jihye; Wang, Guoliang; Purkey, Alicia; Pitts, Todd M.; Nguyen, Anna; Gao, Dexiang; Blatchford, Patrick; Capasso, Anna; Schuller, Alwin G.; Eckhardt, S. Gail; Arcaroli, John J.

    2016-01-01

    Background Dysregulation of the canonical Wnt signaling pathway has been implicated in colorectal cancer (CRC) development as well as incipient stages of malignant transformation. In this study, we investigated the antitumor effects of AZ1366 (a novel tankyrase inhibitor) as a single agent and in combination with irinotecan in our patient derived CRC explant xenograft models. Results Six out of 18 CRC explants displayed a significant growth reduction to AZ1366. There was one CRC explant (CRC040) that reached the threshold of sensitivity (TGII ≤ 20%) in this study. In addition, the combination of AZ1366 + irinotecan demonstrated efficacy in 4 out of 18 CRC explants. Treatment effects on the WNT pathway revealed that tankyrase inhibition was ineffective at reducing WNT dependent signaling. However, the anti-tumor effects observed in this study were likely a result of alternative tankyrase effects whereby tankyrase inhibition reduced NuMA levels. Materials and Methods Eighteen CRC explants were treated with AZ1366 single agent or in combination for 28 days and treatment responses were assessed. Pharmacokinetic (AZ1366 drug concentrations) and pharmacodynamic effects (Axin2 levels) were investigated over 48 hours. Immunohistochemistry of nuclear β-catenin levels as well as western blot was employed to examine the treatment effects on the WNT pathway as well as NuMA. Conclusions Combination AZ1366 and irinotecan achieved greater anti-tumor effects compared to monotherapy. Activity was limited to CRC explants that displayed irinotecan resistance and increased protein levels of tankyrase and NuMA. PMID:27070088

  11. Study on hydrogen removal of AZ91 alloys using ultrasonic argon degassing process.

    PubMed

    Liu, Xuan; Zhang, Zhiqiang; Hu, Wenyi; Le, Qichi; Bao, Lei; Cui, Jianzhong; Jiang, Jiajia

    2015-09-01

    Argon degassing, ultrasonic degassing and a novel ultrasonic argon degassing treatment were applied for the hydrogen removal of AZ91 magnesium alloy. The hydrogen concentration, microstructures and mechanical properties have also been investigated. AZ91 alloys contains a high hydrogen concentration. The mechanical properties of the as-cast alloy are much improved using degassing process, which should be mainly attributed to the hydrogen removal. Among the three degassing process, the ultrasonic argon treatment is a high efficient process both for hydrogen removal and microstructure refining. One hand, ultrasonic wave could break up the purged argon bubble to improve the degassing efficiency of these bubbles. On the other hand, ultrasound could also generate many cavitation bubbles in the melt, which should account for the microstructure refinement. The ultrasonic argon treatment involves dynamics between the ascending argon bubbles and ultrasonic effects, such as cavitation and streaming, etc.

  12. Discovery and antiparasitic activity of AZ960 as a Trypanosoma brucei ERK8 inhibitor.

    PubMed

    Valenciano, Ana L; Ramsey, Aaron C; Santos, Webster L; Mackey, Zachary B

    2016-10-01

    Human African trypanosomiasis (HAT) is a lethal, vector-borne disease caused by the parasite Trypanosoma brucei. Therapeutic strategies for this neglected tropical disease suffer from disadvantages such as toxicity, high cost, and emerging resistance. Therefore, new drugs with novel modes of action are needed. We screened cultured T. brucei against a focused kinase inhibitor library to identify promising bioactive compounds. Among the ten hits identified from the phenotypic screen, AZ960 emerged as the most promising compound with potent antiparasitic activity (IC50=120nM) and was shown to be a selective inhibitor of an essential gene product, T. brucei extracellular signal-regulated kinase 8 (TbERK8). We report that AZ960 has a Ki of 1.25μM for TbERK8 and demonstrate its utility in establishing TbERK8 as a potentially druggable target in T. brucei. PMID:27519462

  13. Project W-314 specific test and evaluation plan for AZ tank farm upgrades

    SciTech Connect

    Hays, W.H.

    1998-08-12

    The purpose of this Specific Test and Evaluation Plan (STEP) is to provide a detailed written plan for the systematic testing of modifications made by the addition of the SN-631 transfer line from the AZ-O1A pit to the AZ-02A pit by the W-314 Project. The STEP develops the outline for test procedures that verify the system`s performance to the established Project design criteria. The STEP is a lower tier document based on the W-314 Test and Evaluation P1 an (TEP). Testing includes Validations and Verifications (e.g., Commercial Grade Item Dedication activities, etc), Factory Tests and Inspections (FTIs), installation tests and inspections, Construction Tests and Inspections (CTIs), Acceptance Test Procedures (ATPs), Pre-Operational Test Procedures (POTPs), and Operational Test Procedures (OTPs). The STEP will be utilized in conjunction with the TEP for verification and validation.

  14. Corrosion Behavior of AZ91D Magnesium Alloy in Three Different Physiological Environments

    NASA Astrophysics Data System (ADS)

    Zhou, Juncen; Li, Qing; Zhang, Haixiao; Chen, Funan

    2014-01-01

    Magnesium alloys have been considered as promising biomedical materials and were studied in different physiological environments. In this work, corrosion behavior of AZ91D magnesium alloy in artificial saliva, simulated body fluid (SBF), and 3.5 wt.% NaCl solution was investigated using electrochemical techniques and a short-term immersion test. In contrast with other physiological environments, the amount of aggressive ions in artificial saliva is small. In addition, a protective film is formed on the surface of samples in artificial saliva. Experimental results suggest that corrosion resistance of AZ91D magnesium alloy in artificial saliva is better than that in c-SBF and 3.5 wt.% NaCl solution.

  15. Passivity and Localized Corrosion of AZ31 Magnesium Alloy in High pH Electrolytes

    NASA Astrophysics Data System (ADS)

    Alsagabi, Sultan; Ninlachart, Jakraphan; Raja, Krishnan S.; Charit, Indrajit

    2016-06-01

    Electrochemical corrosion tests were carried out on AZ31 magnesium alloy specimens in pH: 4.5, 9.5, and 13.0 solutions with 0-2000 ppm of chloride additions at room temperature. No passivity breakdown was observed during cyclic polarization in pH:13 solutions containing up to 1500 ppm of chloride. Addition of sodium sulfate and sodium dihydrogen phosphate as supporting electrolytes offset the chloride effect on the corrosion of AZ31 in pH 4.5 and 9.5 solutions. The Mott-Schottky analysis showed the presence of a duplex surface layer consisting of an n-type MgO1- x inner layer ( x = 0.024-0.05), and a p-type outer layer which thickened with time at the expense of the inner layer.

  16. Evaluation of AY/AZ tank farm ventilation system during aging waste retrieval operations

    SciTech Connect

    Wong, J.J.; Waters, E.D.

    1995-01-01

    Waste Management is currently planning to demonstrate mobilization of radioactive waste sludges in Tank 101-AZ beginning in October 1991. The retrieval system being designed will utilize mixer pumps that generate high-velocity, high-volume submerged liquid jets to mobilize settled solids. There is concern that these jets may also generate radioactive aerosols, some of which may be carried into the tank Ventilation system. The purpose of this study is to determine if the current AY/AZ ventilation system or the proposed ventilation system upgrade (Project W-030) will provide adequate deentrainment of liquid and solid aerosols during mixer pump operations, or if the radioactive aerosols will overload the HEPA filters.

  17. Surface characterization and cytocompatibility evaluation of silanized magnesium alloy AZ91 for biomedical applications

    NASA Astrophysics Data System (ADS)

    Witecka, Agnieszka; Yamamoto, Akiko; Dybiec, Henryk; Swieszkowski, Wojciech

    2012-12-01

    Mg alloys with high Al contents have superior corrosion resistance in aqueous environments, but poor cytocompatibility compared to that of pure Mg. We have silanized the cast AZ91 alloy to improve its cytocompatibility using five different silanes: ethyltriethoxysilane (S1), 3-aminopropyltriethoxysilane (S2), 3-isocyanatopyltriethoxysilane (S3), phenyltriethoxysilane (S4) and octadecyltriethoxysilane (S5). The surface hydrophilicity/hydrophobicity was evaluated by water contact angle measurements. X-ray photoelectron analysis was performed to investigate the changes in surface states and chemical composition. All silane reagents increased adsorption of the albumin to the modified surface. In vitro cytocompatibility evaluation revealed that silanization improved cell growth on AZ91 modified by silane S1. Measurement of the concentration of Mg2+ ions released during the cell culture indicated that silanization does not affect substrate degradation.

  18. An organic chromium-free conversion coating on AZ91D magnesium alloy

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoming; Li, Guangyu; Lian, Jianshe; Jiang, Qing

    2008-12-01

    Traditional conversion coatings on magnesium alloys are usually immersed in a solution containing hexavalent chromium compounds. However, the replacement treatments have been proposed by the present environmental driving to eliminate hexavalent chromium. In this work, a tannic acid based conversion coating on AZ91D magnesium alloy was obtained by treatment in a solution containing tannic acid and ammonium metavanadate. SEM, XPS and IR were used to determine the morphology and structure of the conversion coatings. Continuous and uniform conversion coating was deposited on AZ91D alloy and the main components of the coatings were Al 2O 3, MgF 2 and penta-hydroxy benzamide-magnesium complex. The formation mechanism of the coating was discussed. Polarization measurement and salt spray test showed that the corrosion resistance of the conversion coating was much higher than that of traditional chromate conversion coating.

  19. Torsional and axial damping properties of the AZ31B-F magnesium alloy

    NASA Astrophysics Data System (ADS)

    Anes, V.; Lage, Y. E.; Vieira, M.; Maia, N. M. M.; Freitas, M.; Reis, L.

    2016-10-01

    Damping properties for the AZ31B-F magnesium alloy were evaluated for pure axial and pure shear loading conditions at room temperature. Hysteretic damping results were measured through stress-strain controlled tests. Moreover, the magnesium alloy viscous damping was measured with frequency response functions and free vibration decay, both results were obtained by experiments. The axial and shear damping ratio (ASDR) has been identified and described, specifically for free vibration conditions.

  20. Best Practices Case Study: John Wesley Miller Companies - Armory Park Del Sol, Tucson, AZ

    SciTech Connect

    2009-10-01

    Case study of John Wesley Miller Companies, who built two net zero energy homes plus 97 other solar homes in Tucson, AZ. Masonry block walls with rigid foam exterior sheathing, rigid foam over the roof deck plus R-38 in the attic, ducts in conditioned space, 4.2 kW and 5.7 kW photovoltaics and solar water heating yielded HERS scores of 0 on the two homes.

  1. Effect of Surface Modification on Cumulative Tensile Ductility of AZ31 Magnesium Sheet

    NASA Astrophysics Data System (ADS)

    Habibnejad-korayem, Mahdi; Jain, Mukesh K.; Mishra, Raja K.

    2016-09-01

    Wire brushing and annealing (WBA) process was developed, optimized and utilized to modify the surface layer microstructure of AZ31 automotive magnesium sheet material. The process was carried out using softer brass wire brushes to mitigate the effect of wire brushing on surface quality and damage. The influence of modified surface grain structure and crystallographic texture was studied by continuous uniaxial tension test as well as by a newly proposed multi-step uniaxial stretching and annealing (MUSA) process to assess cumulative uniaxial tensile ductility of AZ31 sheet. A rotational speed of 2800 revolutions per minute for the wire brush with a near-zero depth of cut followed by annealing at 473 K (200 °C) for 60 minutes resulted in acceptable surface quality with a refined grain layer of depth 30 μm, and a modified crystallographic texture on the surface. Material flow behavior, grain microstructure, and texture evolution of WBA-processed material during subsequent MUSA process were analyzed to assess the role of wire brushing in enhancing the MUSA response of AZ31 sheet. Original fully annealed AZ31 sheet (in the non-WBA condition) was also subjected to identical MUSA process for comparison purposes. The results showed improvement in terminal uniaxial tensile ductility of WBA-MUSA-processed material compared to Standard-MUSA material. The ductility improvement is attributed to non-basal texture development and re-distribution of the texture, as well as to grain refinement within the highly deformed surface layer from the combination of WBA and MUSA processes.

  2. Test plan: Laboratory-scale testing of the first core sample from Tank 102-AZ

    SciTech Connect

    Morrey, E.V.

    1996-03-01

    The overall objectives of the Radioactive Process/Product Laboratory Testing (RPPLT), WBS 1.2.2.05.05, are to confirm that simulated HWVP feed and glass are representative of actual radioactive HWVP feed and glass and to provide radioactive leaching and glass composition data to WFQ. This study will provide data from one additional NCAW core sample (102-AZ Core 1) for these purposes.

  3. AzTEC 1.1 mm OBSERVATIONS OF THE MBM12 MOLECULAR CLOUD

    SciTech Connect

    Kim, M. J.; Kim, S.; Youn, S.; Kang, Y.-W.; Yun, M. S.; Wilson, G. W.; Aretxaga, I.; Hughes, D. H.; Humphrey, A.; Williams, J. P.; Austermann, J. E.; Perera, T. A.; Mauskopf, P. D.; Magnani, L.

    2012-02-10

    We present 1.1 mm observations of the dust continuum emission from the MBM12 high-latitude molecular cloud observed with the Astronomical Thermal Emission Camera (AzTEC) mounted on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. We surveyed 6.34 deg{sup 2} centered on MBM12, making this the largest area that has ever been surveyed in this region with submillimeter and millimeter telescopes. Eight secure individual sources were detected with a signal-to-noise ratio of over 4.4. These eight AzTEC sources can be considered to be real astronomical objects compared to the other candidates based on calculations of the false detection rate. The distribution of the detected 1.1 mm sources or compact 1.1 mm peaks is spatially anti-correlated with that of the 100 {mu}m emission and the {sup 12}CO emission. We detected the 1.1 mm dust continuum emitting sources associated with two classical T Tauri stars, LkH{alpha}262 and LkH{alpha}264. Observations of spectral energy distributions (SEDs) indicate that LkH{alpha}262 is likely to be Class II (pre-main-sequence star), but there are also indications that it could be a late Class I (protostar). A flared disk and a bipolar cavity in the models of Class I sources lead to more complicated SEDs. From the present AzTEC observations of the MBM12 region, it appears that other sources detected with AzTEC are likely to be extragalactic and located behind MBM12. Some of these have radio counterparts and their star formation rates are derived from a fit of the SEDs to the photometric evolution of galaxies in which the effects of a dusty interstellar medium have been included.

  4. Comparison of simulants to actual neutralized current acid waste: Process and product testing of three NCAW core samples from Tanks 101-AZ and 102-AZ

    SciTech Connect

    Morrey, E.V.; Tingey, J.M.

    1996-04-01

    A vitrification plant is planned to process the high-level waste (HLW) solids from Hanford Site tanks into canistered glass logs for disposal in a national repository. Programs have been established within the Pacific Northwest Laboratory Vitrification Technology Development (PVTD) Project to test and model simulated waste to support design, feed processability, operations, permitting, safety, and waste-form qualification. Parallel testing with actual radioactive waste is being performed on a laboratory-scale to confirm the validity of using simulants and glass property models developed from simulants. Laboratory-scale testing has been completed on three radioactive core samples from tanks 101-AZ and 102-AZ containing neutralized current acid waste (NCAW), which is one of the first waste types to be processed in the high-level waste vitrification plant under a privatization scenario. Properties of the radioactive waste measured during process and product testing were compared to simulant properties and model predictions to confirm the validity of simulant and glass property models work. This report includes results from the three NCAW core samples, comparable results from slurry and glass simulants, and comparisons to glass property model predictions.

  5. Comparison of simulants to actual neutralized current acid waste: process and product testing of three NCAW core samples from Tanks 101-AZ and 102-AZ

    SciTech Connect

    Morrey, E.V.; Tingey, J.M.; Elliott, M.L.

    1996-10-01

    A vitrification plant is planned to process the high-level waste (HLW) solids from Hanford Site tanks into canistered glass logs for disposal in a national repository. Programs were established within the Pacific Northwest Laboratory Vitrification Technology Development (PVTD) Project to test and model simulated waste to support design, feed processability, operations, permitting, safety, and waste-form qualification. Parallel testing with actual radioactive waste was performed on a laboratory-scale to confirm the validity of using simulants and glass property models developed from simulants. Laboratory-scale testing has been completed on three radioactive core samples from tanks 101-AZ and 102-AZ containing neutralized current acid waste (NCAW), which is one of the first waste types to be processed in the high-level waste vitrification plant under a privatization scenario. Properties of the radioactive waste measured during process and product testing were compared to simulant properties and model predictions to confirm the validity of simulant and glass property ,models work. This report includes results from the three NCAW core samples, comparable results from slurry and glass simulants, and comparisons to glass property model predictions.

  6. Profiling gene expression in citrus fruit calyx abscission zone (AZ-C) treated with ethylene.

    PubMed

    Cheng, Chunzhen; Zhang, Lingyun; Yang, Xuelian; Zhong, Guangyan

    2015-10-01

    On-tree storage and harvesting of mature fruit account for a large proportion of cost in the production of citrus, and a reduction of the cost would not be achieved without a thorough understanding of the mechani sm of the mature fruit abscission. Genome-wide gene expression changes in ethylene-treated fruit calyx abscission zone (AZ-C) of Citrus sinensis cv. Olinda were therefore investigated using a citrus genome array representing up to 33,879 citrus transcripts. In total, 1313 and 1044 differentially regulated genes were identified in AZ-C treated with ethylene for 4 and 24 h, respectively. The results showed that mature citrus fruit abscission commenced with the activation of ethylene signal transduction pathway that led to the activation of ethylene responsive transcription factors and the subsequent transcriptional regulation of a large set of ethylene responsive genes. Significantly down-regulated genes included those of starch/sugar biosynthesis, transportation of water and growth promoting hormone synthesis and signaling, whereas significantly up-regulated genes were those involved in defense, cell wall degradation, and secondary metabolism. Our data unraveled the underlying mechanisms of some known important biochemical events occurring at AZ-C and should provide informative suggestions for future manipulation of the events to achieve a controllable abscission for mature citrus fruit. PMID:25948248

  7. Profiling gene expression in citrus fruit calyx abscission zone (AZ-C) treated with ethylene.

    PubMed

    Cheng, Chunzhen; Zhang, Lingyun; Yang, Xuelian; Zhong, Guangyan

    2015-10-01

    On-tree storage and harvesting of mature fruit account for a large proportion of cost in the production of citrus, and a reduction of the cost would not be achieved without a thorough understanding of the mechani sm of the mature fruit abscission. Genome-wide gene expression changes in ethylene-treated fruit calyx abscission zone (AZ-C) of Citrus sinensis cv. Olinda were therefore investigated using a citrus genome array representing up to 33,879 citrus transcripts. In total, 1313 and 1044 differentially regulated genes were identified in AZ-C treated with ethylene for 4 and 24 h, respectively. The results showed that mature citrus fruit abscission commenced with the activation of ethylene signal transduction pathway that led to the activation of ethylene responsive transcription factors and the subsequent transcriptional regulation of a large set of ethylene responsive genes. Significantly down-regulated genes included those of starch/sugar biosynthesis, transportation of water and growth promoting hormone synthesis and signaling, whereas significantly up-regulated genes were those involved in defense, cell wall degradation, and secondary metabolism. Our data unraveled the underlying mechanisms of some known important biochemical events occurring at AZ-C and should provide informative suggestions for future manipulation of the events to achieve a controllable abscission for mature citrus fruit.

  8. Formability of Ultrafine-Grain Mg Alloy AZ31B at Warm Temperatures

    NASA Astrophysics Data System (ADS)

    Yang, Q.; Ghosh, A. K.

    2008-11-01

    Warm formability of ultrafine-grain (UFG) AZ31B Mg alloy in the range of 150 °C to 311 °C is investigated. Refinement of grain size significantly improves the formability primarily through increasing strain rate sensitivity of flow stress and increasing diffuse quasi-stable flow, as compared with the coarse-grain AZ31B alloy. Strain rate sensitivity increases with increasing temperatures, and seems to be connected with dynamic recovery and grain boundary processes. For fine-grain sizes, twinning is inhibited. At 200 °C and strain rates below 2 × 10-4 s-1, the UFG AZ31B alloy demonstrates a high rate of strain hardening up to a true strain of 0.6, in addition to its high strain rate sensitivity, which is responsible for its enhanced formability. Examination of the microstructure shows that there is competition between dynamic grain growth and grain refinement during deformation at modest warm forming temperatures, the former causing hardening and the latter causing softening. Increasing the test strain rate and starting with larger grain size initiates deformation twinning during forming, and assists in the refinement of the coarser grains followed by recrystallization.

  9. A cellular automaton model for microstructural simulation of friction stir welded AZ91 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Akbari, Mostafa; Asadi, Parviz; Besharati Givi, MohammadKazem; Zolghadr, Parisa

    2016-03-01

    To predict the grain size and microstructure evolution during friction stir welding (FSW) of AZ91 magnesium alloy, a finite element model (FEM) is developed based on the combination of a cellular automaton model and the Kocks  -  Mecking and Laasraoui-Jonas models. First, according to the flow stress curves and using the Kocks  -  Mecking model, the hardening and recovery parameters and the strain rate sensitivity were calculated. Next, an FEM model was established in Deform-3D software to simulate the FSW of AZ91 magnesium alloy. The results of the FEM model are used in microstructure evolution models to predict the grain size and microstructure of the weld zone. There is a good agreement between the simulated and experimental microstructures, and the proposed model can simulate the dynamic recrystallization (DRX) process during FSW of AZ91 alloy. Moreover, microstructural properties of different points in the SZ as well as the effect of the w/v parameter on the grain size and microstructure are considered.

  10. Synthesis of dittmarite/Mg(OH)2 composite coating on AZ31 using hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Zhao, Qing; Mahmood, Waqas; Zhu, Yanying

    2016-03-01

    In this work, we have used hydrothermal method for the synthesis of dittmarite/Mg(OH)2 composite (DMC) layer on AZ31 alloy of magnesium. The synthesized coating was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS). In a test immersion into the Hank's mixture for 31 days, the synthesized coating inhibited corrosion of AZ31 significantly and the amorphous calcium apatite precursor deposited on the coating surface. In another tape test, we noticed strong adhesion between the coating and substrate that eventually concludes that the synthesized coating is hydrophilic and a promising candidate to be used in the absorbable implant materials. Besides, the cytotoxicity of the AZ31 alloy with DMC coating, grown under different conditions on L-929 cells in vitro was examined indirectly through the growth inhibition method (MTT assay). The cytotoxicity of the deposited coating lie between 0 ∼ 1 that indicates it as a promising biomaterial.

  11. Texture Evolution and Twinning During the Expansion of Hot Extruded AZ31 + Sr Seamless Tubes

    NASA Astrophysics Data System (ADS)

    Sadeghi, Alireza; Martin, Étienne; Pekguleryuz, Mihriban

    2014-12-01

    Seamless tubes of AZ31, AZ31 + 0.4, and 0.8 wt pctSr were extruded at elevated temperatures. By compressing pure copper inserts inside the tubes, the extruded tubes were expanded at room and elevated temperatures [373 K and 473 K (100 °C and 200 °C)]. Microstructural examinations reveal the formation of twining in the as-extruded and expanded tubes. The amount of twinning decreased with increasing level of Sr in the expanded microstructures as a result of grain refinement and of decreasing Al in solution that facilitates dislocation motion. During expansion at room temperature, AZ31 shows higher elongation and lower strength than the alloys containing Sr. At 473 K (200 °C), compared to the lower temperatures, the Sr containing alloys exhibit lower flow stress and no fracture in the strain range investigated (40 pct reduction in cylinder height). The textures of the extruded alloys contain two main components named as RD ( c-axis parallel to the radial direction) and HD ( c-axis parallel to the hoop direction) based on their orientation with the sample coordinates. During expansion, extension twinning in the HD grains reorients the lattice to strengthen the RD and form a new ED ( c-axis parallel to the extrusion direction) component. By increasing the temperature or level of Sr, the ED component is weakened due to the decrease in twinning. During expansion, the RD grains undergo contraction and double twining which reduce the overall texture strength.

  12. Texture Evolution and Twinning During the Expansion of Hot Extruded AZ31 + Sr Seamless Tubes

    NASA Astrophysics Data System (ADS)

    Sadeghi, Alireza; Martin, Étienne; Pekguleryuz, Mihriban

    2014-09-01

    Seamless tubes of AZ31, AZ31 + 0.4, and 0.8 wt pctSr were extruded at elevated temperatures. By compressing pure copper inserts inside the tubes, the extruded tubes were expanded at room and elevated temperatures [373 K and 473 K (100 °C and 200 °C)]. Microstructural examinations reveal the formation of twining in the as-extruded and expanded tubes. The amount of twinning decreased with increasing level of Sr in the expanded microstructures as a result of grain refinement and of decreasing Al in solution that facilitates dislocation motion. During expansion at room temperature, AZ31 shows higher elongation and lower strength than the alloys containing Sr. At 473 K (200 °C), compared to the lower temperatures, the Sr containing alloys exhibit lower flow stress and no fracture in the strain range investigated (40 pct reduction in cylinder height). The textures of the extruded alloys contain two main components named as RD (c-axis parallel to the radial direction) and HD (c-axis parallel to the hoop direction) based on their orientation with the sample coordinates. During expansion, extension twinning in the HD grains reorients the lattice to strengthen the RD and form a new ED (c-axis parallel to the extrusion direction) component. By increasing the temperature or level of Sr, the ED component is weakened due to the decrease in twinning. During expansion, the RD grains undergo contraction and double twining which reduce the overall texture strength.

  13. 78 FR 60698 - Safety Zone, Lucas Oil Drag Boat Racing Series; Thompson Bay, Lake Havasu City, AZ.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-02

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice... prohibited from entering into, transiting through, or anchoring within this safety zone unless authorized by... entering into, transiting through, or anchoring within this safety zone unless authorized by the Captain...

  14. Histone chaperone Anp32e removes H2A.Z from DNA double-strand breaks and promotes nucleosome reorganization and DNA repair.

    PubMed

    Gursoy-Yuzugullu, Ozge; Ayrapetov, Marina K; Price, Brendan D

    2015-06-16

    The repair of DNA double-strand breaks (DSBs) requires open, flexible chromatin domains. The NuA4-Tip60 complex creates these flexible chromatin structures by exchanging histone H2A.Z onto nucleosomes and promoting acetylation of histone H4. Here, we demonstrate that the accumulation of H2A.Z on nucleosomes at DSBs is transient, and that rapid eviction of H2A.Z is required for DSB repair. Anp32e, an H2A.Z chaperone that interacts with the C-terminal docking domain of H2A.Z, is rapidly recruited to DSBs. Anp32e functions to remove H2A.Z from nucleosomes, so that H2A.Z levels return to basal within 10 min of DNA damage. Further, H2A.Z removal by Anp32e disrupts inhibitory interactions between the histone H4 tail and the nucleosome surface, facilitating increased acetylation of histone H4 following DNA damage. When H2A.Z removal by Anp32e is blocked, nucleosomes at DSBs retain elevated levels of H2A.Z, and assume a more stable, hypoacetylated conformation. Further, loss of Anp32e leads to increased CtIP-dependent end resection, accumulation of single-stranded DNA, and an increase in repair by the alternative nonhomologous end joining pathway. Exchange of H2A.Z onto the chromatin and subsequent rapid removal by Anp32e are therefore critical for creating open, acetylated nucleosome structures and for controlling end resection by CtIP. Dynamic modulation of H2A.Z exchange and removal by Anp32e reveals the importance of the nucleosome surface and nucleosome dynamics in processing the damaged chromatin template during DSB repair.

  15. Strategies to reduce the harmful effects of extreme heat events: a four-city study.

    PubMed

    White-Newsome, Jalonne L; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A; O'Neill, Marie S; Gronlund, Carina J; Catalano, Linda; Conlon, Kathryn C; Parker, Edith A

    2014-02-13

    Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ-cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality.

  16. Strategies to reduce the harmful effects of extreme heat events: a four-city study.

    PubMed

    White-Newsome, Jalonne L; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A; O'Neill, Marie S; Gronlund, Carina J; Catalano, Linda; Conlon, Kathryn C; Parker, Edith A

    2014-02-01

    Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ-cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality. PMID:24531122

  17. Jerusalem: City of Dreams, City of Sorrows

    ERIC Educational Resources Information Center

    Ricks, Thomas

    2011-01-01

    Jerusalem is more than an intriguing global historical city; it is a classroom for liberal learning and international understanding. It had never been a city of one language, one religion and one culture. Looking at the origins of Jerusalem's name indicates its international and multicultural nature. While Israelis designate Jerusalem as their…

  18. What Is Clean Cities?

    SciTech Connect

    Not Available

    2007-08-01

    This Clean Cities Program fact sheet describes the purpose and scope of this DOE program. Clean Cities facilitates the use of alternative and advanced fuels and vehicles to displace petroleum in the transportation sector.

  19. Biochemical assay for histone H2A.Z replacement by the yeast SWR1 chromatin remodeling complex.

    PubMed

    Mizuguchi, Gaku; Wu, Wei-Hua; Alami, Samar; Luk, Ed

    2012-01-01

    The evolutionarily conserved histone variant H2A.Z has an important role in the regulation of gene expression and the establishment of a buffer to the spread of silent heterochromatin. Saccharomyces cerevisiae Swr1, a Swi2/Snf2-related ATPase, is the catalytic core of a multisubunit chromatin remodeling enzyme, called the SWR1 complex, that efficiently replaces conventional histone H2A in nucleosomes with histone H2A.Z. Swr1 is required for the deposition of histone H2A.Z at stereotypical promoter locations in vivo, and Swr1 and H2A.Z commonly regulate a subset of yeast genes. Here, we describe an integrated nucleosome assembly-histone replacement system whereby histone exchange by chromatin remodeling activities may be analyzed in vitro. The system demonstrates ATP- and SWR1-complex-dependent replacement of histone H2A for histone H2A.Z on a preassembled nucleosome array. This system may also be adapted to analyze dynamic interactions between chromatin remodeling and modifying enzymes, histone chaperones, and nucleosome substrates containing canonical, variant, or covalently modified histones. PMID:22910211

  20. Combined effect of pulse electron beam treatment and thin hydroxyapatite film on mechanical features of biodegradable AZ31 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Surmeneva, M. A.; Tyurin, A. I.; Teresov, A. D.; Koval, N. N.; Pirozhkova, T. S.; Shuvarin, I. A.; Surmenev, R. A.

    2015-11-01

    The morphology, elemental, phase composition, nanohardness, and Young's modulus of the hydroxyapatite (HA) coating deposited via radio frequency (RF) magnetron sputtering onto the AZ31 surface were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and nanoindentationtechniques. The calcium phosphate (Ca/P) molar ratio of the HA coating deposited via RF-magnetron sputtering onto AZ31 substrates according to EDX was 1.57+0.03. The SEM experiments revealed significant differences in the morphology of the HA film deposited on untreated and treated with the pulsed electron beam (PEB) AZ31 substrate. Nanoindentation studies demonstrated significant differences in the mechanical responses of the HA film deposited on the initial and PEB-modified AZ31 substrates. The nanoindentation hardness and the Young's modulus of the HA film on the magnesium alloy modified using the PEB treatment were higher than that of the HA layer on the untreated substrate. Moreover, the HA film fabricated onto the PEB-treated surface was more resistant to plastic deformation than the same film on the untreated AZ31 surface.

  1. 2003 AZ84: Size, shape, albedo and first detection of topographic features

    NASA Astrophysics Data System (ADS)

    Dias-Oliveira, Alex; Sicardy, Bruno; Ortiz, Jose-Luis; Braga-Ribas, Felipe; Vieira-Martins, Roberto; BENEDETTI Rossi, Gustavo; camargo, julio; Assafin, Marcelo; Gomes-Júnior, Altair; Baug, Tapas; Chandrasekhar, Thyagarajan; Duffard, Rene; Ergang, Zhao; Ganesh Ganesh, Shashikiran; Ikari, Yasukazu; Irawati, Puji; Jain, Rajmal; Liying, Zhu; Richichi, Andrea; Shengbang, Qian; Behrend, Raoul; Benkhaldoun, Zouhair; Brosch, Noah; Daassou, Ahmed; Gal-Yam's, Avishay; Garcia-Lozano, Rubén; Gillon, Michael; Jehin, Emmanuel; Kaspi, Shai; Klotz, Alain; Lecacheux, Jean; Mahasena, Putra; Manfroid, Jean; Manulis, Ilan; Maury, Alain; Mohan, Vijay; Morales, Nicolas; Rinner, Claudine; Roques, françoise; Sharma, Amar; Sposetti, Stefano; Tanga, Paolo; Thirouin, Audrey; Vachier, Frederic; Widemann, Thomas

    2016-10-01

    We analyze two multi-chord stellar occultations by the Trans-Neptunian Object (TNO) 2003 AZ84 observed on February 3, 2012 and November 15, 2014.They provide different elliptical limb fits that are consistent to within their respective error bars, but could also suggest a possible precession of the object (assumed here to be a Maclaurin spheroid). The derived equatorial radius and oblateness are Re = 393 ± 7 km and ɛ = 0.057 in 2014 and Re = 414 ± 13 km and ɛ = 0.165 in 2012, respectively. Those results are consistent with single-chord events observed in January 2011 and December 2013. The figures above provide geometric visual albedos of pV(2014) = 0.112 ± 0.008 and pV(2012) = 0.114 ± 0.020. Using the Maclaurin assumption, combined with possible rotational periods of 6.67 h and 10.56 h, we estimate density upper limits of 1.89 ± 0.16g/cm3 and 0.77 ± 0.07g/cm3 for the two dates, respectively.The 2014 event provides (for the first time during a TNO occultation) a grazing chord with a gradual disappearance of the star behind 2003AZ84's limb that lasts for more than 10 seconds. We rule out the possibility of a localized dust concentration as it would imply very high optical depth for that cloud. We favor a local topographic feature (chasm) with minimum width and depth of 22 ± 2.5 km and 7 ± 2.0 km, respectively. Features with similar depths are in fact observed on Pluto's main satellite, Charon, which has a radius of about 605 km, comparable to that of 2003AZ84.

  2. Ultrasonic Examination of Double-Shell Tank 241-AZ-101. Examination Completed July 2007.

    SciTech Connect

    Pardini, Allan F.; Weier, Dennis R.

    2007-08-12

    AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AZ-101. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-AZ-101 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-Plan-27202 (Jensen 2005) and summarized on page 1 of this document, are to be reported to CH2M HILL and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M HILL, all data is to be recorded on electronic media and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The results of the examination of Tank 241-AZ-101 have been evaluated by PNNL personnel. The ultrasonic examination consisted of two vertical 15-in.-wide scan paths over the entire height of the tank and the heat-affected zone (HAZ) of five vertical welds and one horizontal weld from Riser 89. The examination also included two vertical 15-in.-wide scan paths over the entire height of the tank from Riser 90. The examination was performed to detect any wall thinning, pitting, or cracking in the primary tank wall.

  3. Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11.

    PubMed

    Lee, Eun Young; Lee, Nae Yoon; Cho, Kyung-Suk; Ryu, Hee Wook

    2006-04-01

    Toxic H2S gas is an important industrial pollutant that is applied to biofiltration. Here, we examined the effects of factors such as inlet concentration and space velocity on the removal efficiency of a bacterial strain capable of tolerating high sulfate concentrations and low pH conditions. We examined three strains of Acidithiobacillus thiooxidans known to have sulfur-oxidizing activity, and identified strain AZ11 as having the highest tolerance for sulfate. A. thiooxidans AZ11 could grow at pH 0.2 in the presence of 74 g l(-1) sulfate, the final oxidation product of elemental sulfur, in the culture broth. Under these conditions, the specific sulfur oxidation rate was 2.9 g-S g-DCW (dry cell weight)(-1) d(-1). The maximum specific sulfur oxidation rate of A. thiooxidans AZ11 was 21.2 g-S g-DCW(-1) d(-1), which was observed in the presence of 4.2 g-SO4(2-) l(-1) and pH 1.5, in the culture medium. To test the effects of various factors on biofiltration by this strain, A. thiooxidans AZ11 was inoculated into a porous ceramic biofilter. First, a maximum inlet loading of 670 g-S m(-3) h(-1) was applied with a constant space velocity (SV) of 200 h(-1) (residence time, 18 s) and the inlet concentration of H2S was experimentally increased from 200 ppmv to 2200 ppmv. Under these conditions, less than 0.1 ppmv H2S was detected at the biofilter outlet. When the inlet H2S was maintained at a constant concentration of 200 ppmv and the SV was increased from 200 h(-1) to 400 h(-1) (residence time, 9 s), an H2S removal of 99.9% was obtained. However, H2S removal efficiencies decreased to 98% and 94% when the SV was set to 500 h(-1) (residence time, 7.2 s) and 600 h(-1) (residence time, 6 s), respectively. The critical elimination capacity guaranteeing 96% removal of the inlet H2S was determined to be 160 g-S m(-3) h(-1) at a space velocity of 600 h(-1). Collectively, these findings show for the first time that a sulfur oxidizing bacterium has a high sulfate tolerance and a high

  4. Evaluation of 241-AZ tank farm supporting phase 1 privatization waste feed delivery

    SciTech Connect

    CARLSON, A.B.

    1998-11-19

    This evaluation is one in a series of evaluations determining the process needs and assessing the adequacy of existing and planned equipment in meeting those needs at various double-shell tank farms in support of Phase 1 privatization. A number of tank-to-tank transfers and waste preparation activities are needed to process and feed waste to the private contractor in support of Phase 1 privatization. The scope of this evaluation is limited to process needs associated with 241-AZ tank farm during the Phase 1 privatization.

  5. Exotic decays of a heavy neutral Higgs through HZ/AZ channel

    NASA Astrophysics Data System (ADS)

    Coleppa, Baradhwaj; Kling, Felix; Su, Shufang

    2014-09-01

    Models of electroweak symmetry breaking with extended Higgs sectors are theoretically well motivated. In this study, we focus on the Two Higgs Doublet Model with a low energy spectrum containing scalars H and a pseudoscalar A. We study the decays A → HZ or H → AZ, which could reach sizable branching fractions in certain parameter regions. With detailed collider analysis, we obtain model independent exclusion bounds as well as discovery reach at the 14 TeV LHC for the process: gg → A/ H → HZ/ AZ, looking at final states bbℓℓ, ττℓℓ and ZZZ(4 ℓ + 2 j) for ℓ = e, μ. We further interpret these bounds in the context of the Type II Two Higgs Doublet Model, considering three different classes of processes: A → h 0 Z, A → H 0 Z, and H 0 → AZ, in which h 0 and H 0 are the light and heavy CP-even Higgses respectively. For 100 fb-1 integrated luminosity at the 14 TeV LHC, we find that for parent particle mass around 300-400 GeV, A → h 0 Z has the greatest reach when H 0 is interpreted as the 126 GeV Higgs: most regions in the tan β versus sin( β - α) plane can be excluded and a significant fraction at small and large tan β can be covered by discovery. For 126 GeV h 0, only relatively small tan β ≲ 10 (5) can be reached by exclusion (discovery) while a wide range of sin( β - α) is accessible. For A → H 0 Z, the reach is typically restricted to sin( β - α) ~ ±1 with tan β ≲ 10 in bbℓℓ and ττℓℓ channels. The ZZZ(4 ℓ2 j) channel, on the other hand, covers a wide range of 0 .3 < | sin( β - α)| < 1 for tan β ≲ 4. H 0 → AZ typically favors negative values of sin( β - α), with exclusion/discovery reach possibly extending to all values of tan β. A study of exotic decays of extra Higgses appearing in extensions of the Standard Model would extend the reach at the LHC and provides nice complementarity to conventional Higgs search channels.

  6. In vitro corrosion of pure magnesium and AZ91 alloy—the influence of thin electrolyte layer thickness

    PubMed Central

    Zeng, Rong-Chang; Qi, Wei-Chen; Zhang, Fen; Li, Shuo-Qi

    2016-01-01

    In vivo degradation predication faces a huge challenge via in vitro corrosion test due to the difficulty for mimicking the complicated microenvironment with various influencing factors. A thin electrolyte layer (TEL) cell for in vitro corrosion of pure magnesium and AZ91 alloy was presented to stimulate the in vivo corrosion in the micro-environment built by the interface of the implant and its neighboring tissue. The results demonstrated that the in vivo corrosion of pure Mg and the AZ91 alloy was suppressed under TEL condition. The AZ91 alloy was more sensitive than pure Mg to the inhibition of corrosion under a TEL thickness of less than 200 µm. The TEL thickness limited the distribution of current, and thus localized corrosion was more preferred to occur under TEL condition than in bulk solution. The TEL cell might be an appropriate approach to simulating the in vivo degradation of magnesium and its alloys. PMID:26816655

  7. 77 FR 19610 - Marc Knapp, Inmate #-06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548; Order Denying...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Bureau of Industry and Security Marc Knapp, Inmate --06450-015, FCI Safford, P.O. Box 9000, Safford, AZ....O. Box 9000, Safford, AZ 85548, and when acting for or on behalf of Knapp, his...

  8. Targeting of the SUN protein Mps3 to the inner nuclear membrane by the histone variant H2A.Z

    PubMed Central

    Gardner, Jennifer M.; Smoyer, Christine J.; Stensrud, Elizabeth S.; Alexander, Richard; Gogol, Madelaine; Wiegraebe, Winfried

    2011-01-01

    Understanding the relationship between chromatin and proteins at the nuclear periphery, such as the conserved SUN family of inner nuclear membrane (INM) proteins, is necessary to elucidate how three-dimensional nuclear architecture is established and maintained. We found that the budding yeast SUN protein Mps3 directly binds to the histone variant H2A.Z but not other histones. Biochemical and genetic data indicate that the interaction between Mps3 and H2A.Z requires the Mps3 N-terminal acidic domain and unique sequences in the H2A.Z N terminus and histone-fold domain. Analysis of binding-defective mutants showed that the Mps3–H2A.Z interaction is not essential for any previously described role for either protein in nuclear organization, and multiple lines of evidence suggest that Mps3–H2A.Z binding occurs independently of H2A.Z incorporation into chromatin. We demonstrate that H2A.Z is required to target a soluble Mps3 fragment to the nucleus and to localize full-length Mps3 in the INM, indicating that H2A.Z has a novel chromatin-independent function in INM targeting of SUN proteins. PMID:21518795

  9. 76 FR 54288 - Notice of Final Federal Agency Actions on Proposed Bridge and Approach Roadways in Nevada and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... Federal Highway Administration Notice of Final Federal Agency Actions on Proposed Bridge and Approach... proposed Laughlin-Bullhead City Bridge project in Laughlin, Clark County, Nevada; and in Bullhead City... claim seeking judicial review of the Federal agency actions on the bridge and roadway project will...

  10. Physical properties of the extreme Centaur and super-comet candidate 2013 AZ60

    NASA Astrophysics Data System (ADS)

    Pál, A.; Kiss, Cs.; Horner, J.; Szakáts, R.; Vilenius, E.; Müller, Th. G.; Acosta-Pulido, J.; Licandro, J.; Cabrera-Lavers, A.; Sárneczky, K.; Szabó, Gy. M.; Thirouin, A.; Sipőcz, B.; Dózsa, Á.; Duffard, R.

    2015-11-01

    We present estimates of the basic physical properties including size and albedo of the extreme Centaur 2013 AZ60. These properties have been derived from optical and thermal infrared measurements. Our optical measurements revealed a probable full period of ≈9.4 h with a shallow amplitude of 4.5%. By combining optical brightness information and thermal emission data, we are able to derive a diameter of 62.3 ± 5.3 km and a geometric albedo of 2.9%, which corresponds to an extremely dark surface. Additionally, our finding of ≳50 Jm-2 K-1 s- 1/2 for the thermal inertia is also remarkable for objects in such a distance. The results of dynamical simulations yield an unstable orbit, with a 50% probability that the target will be ejected from the solar system within 700 000 yr. The current orbit of this object and its instability could imply a pristine cometary surface. This possibility agrees with the observed low geometric albedo and red photometric colour indices for the object, which match the surface of a dormant comet well, as would be expected for a long-period cometary body approaching perihelion. Although it was approaching ever closer to the Sun, however, the object exhibited star-like profiles in each of our observations, lacking any sign of cometary activity. According to the albedo, 2013 AZ60 is a candidate for the darkest body among the known trans-Neptunian objects.

  11. A cross-shear deformation for optimizing the strength and ductility of AZ31 magnesium alloys.

    PubMed

    Hamad, Kotiba; Ko, Young Gun

    2016-01-01

    Magnesium alloys have recently attracted great interest due their lightweight and high specific strength. However, because of their hexagonal close-packed structure, they have few active slip systems, resulting in poor ductility and high mechanical anisotropy at room temperature. In the present work, we used a cross-shear deformation imposed by a differential speed rolling (DSR) technique to improve the room temperature strength and ductility of AZ31 magnesium alloy sheets. To introduce the cross-shear deformation, the sheets were rotated 180° around their longitudinal axis between the adjacent passes of DSR. The sheets of the AZ31 alloy subjected to the cross-shear deformation showed a uniform fine microstructure (1.2 ± 0.1 μm) with weak basal textures. The fabricated sheets showed a simultaneous high ultimate tensile strength and elongation-to-failure, i.e., ~333 MPa and ~21%, respectively. These were explained based on the structural features evolved due to the cross-shear deformation by DSR. The high strength was attributed to the uniform fine microstructure, whereas the high ductility was explained based on the basal texture weakening. PMID:27406685

  12. Research on the drawing process with a large total deformation wires of AZ31 alloy

    NASA Astrophysics Data System (ADS)

    Bajor, T.; Muskalski, Z.; Suliga, M.

    2010-07-01

    Magnesium and their alloys have been extensively studied in recent years, not only because of their potential applications as light-weight engineering materials, but also owing to their biodegradability. Due to their hexagonal close-packed crystallographic structure, cold plastic processing of magnesium alloys is difficult. The preliminary researches carried out by the authors have indicated that the application of the KOBO method, based on the effect of cyclic strain path change, for the deformation of magnesium alloys, provides the possibility of obtaining a fine-grained structure material to be used for further cold plastic processing with large total deformation. The main purpose of this work is to present research findings concerning a detailed analysis of mechanical properties and changes occurring in the structure of AZ31 alloy wire during the multistage cold drawing process. The appropriate selection of drawing parameters and the application of multistep heat treatment operations enable the deformation of the AZ31 alloy in the cold drawing process with a total draft of about 90%.

  13. Geologie study off gravels of the Agua Fria River, Phoenix, AZ

    USGS Publications Warehouse

    Langer, W.H.; Dewitt, E.; Adams, D.T.; O'Briens, T.

    2010-01-01

    The annual consumption of sand and gravel aggregate in 2006 in the Phoenix, AZ metropolitan area was about 76 Mt (84 million st) (USGS, 2009), or about 18 t (20 st) per capita. Quaternary alluvial deposits in the modern stream channel of the Agua Fria River west of Phoenix are mined and processed to provide some of this aggregate to the greater Phoenix area. The Agua Fria drainage basin (Fig. 1) is characterized by rugged mountains with high elevations and steep stream gradients in the north, and by broad alluvial filled basins separated by elongated faultblock mountain ranges in the south. The Agua Fria River, the basin’s main drainage, flows south from Prescott, AZ and west of Phoenix to the Gila River. The Waddel Dam impounds Lake Pleasant and greatly limits the flow of the Agua Fria River south of the lake. The southern portion of the watershed, south of Lake Pleasant, opens out into a broad valley where the river flows through urban and agricultural lands to its confluence with the Gila River, a tributary of the Colorado River.

  14. Laser surface modification of AZ31B Mg alloy for bio-wettability.

    PubMed

    Ho, Yee-Hsien; Vora, Hitesh D; Dahotre, Narendra B

    2015-02-01

    Magnesium alloys are the potential degradable materials for load-bearing implant application due to their comparable mechanical properties to human bone, excellent bioactivity, and in vivo non-toxicity. However, for a successful load-bearing implant, the surface of bio-implant must allow protein absorption and layer formation under physiological environment that can assist the cell/osteoblast growth. In this regard, surface wettability of bio-implant plays a key role to dictate the quantity of protein absorption. In light of this, the main objective of the present study was to produce favorable bio-wettability condition of AZ31B Mg alloy bio-implant surface via laser surface modification technique under various laser processing conditions. In the present efforts, the influence of laser surface modification on AZ31B Mg alloy surface on resultant bio-wettability was investigated via contact-angle measurements and the co-relationships among microstructure (grain size), surface roughness, surface energy, and surface chemical composition were established. In addition, the laser surface modification technique was simulated by computational (thermal) model to facilitate the prediction of temperature and its resultant cooling/solidification rates under various laser processing conditions for correlating with their corresponding composition and phase evolution. These predicted thermal properties were later used to correlate with the corresponding microstructure, chemical composition, and phase evolution via experimental analyses (X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy).

  15. Thermal stability of bimodal microstructure in magnesium alloy AZ91 processed by ECAP

    SciTech Connect

    Pantělejev, Libor

    2015-09-15

    The changes in microstructure of equal channel angular pressing (ECAP) processed magnesium alloy AZ91 during thermal exposure were studied in this paper. The microstructure stability was investigated by means of electron backscatter diffraction (EBSD), which allowed to measure the changes in grain size, mutual ratio of low-angle boundaries (LABs) to high-angle ones (HABs) and local lattice distortion evaluated by the kernel average misorientation (KAM) parameter. It was found experimentally that the threshold temperature at which significant grain coarsening takes place is 350 °C. No modification to mean grain diameter occurs below this temperature, nonetheless, some changes in LAB and HAB fraction, as well as in local lattice distortion, can be observed. - Highlights: • Thermal stability of bimodal UFG AZ91 alloy was assessed by means of EBSD. • Threshold temperature for pronounced grain coarsening was found at 350 °C. • Below 350 °C increase in LAB fraction and local lattice distortion takes place. • Local lattice distortion (LLD) can be well described using KAM approach. • LLD is influenced by coarsening and precipitation of Mg{sub 17}Al{sub 12} particles.

  16. A cross-shear deformation for optimizing the strength and ductility of AZ31 magnesium alloys

    PubMed Central

    Hamad, Kotiba; Ko, Young Gun

    2016-01-01

    Magnesium alloys have recently attracted great interest due their lightweight and high specific strength. However, because of their hexagonal close-packed structure, they have few active slip systems, resulting in poor ductility and high mechanical anisotropy at room temperature. In the present work, we used a cross-shear deformation imposed by a differential speed rolling (DSR) technique to improve the room temperature strength and ductility of AZ31 magnesium alloy sheets. To introduce the cross-shear deformation, the sheets were rotated 180° around their longitudinal axis between the adjacent passes of DSR. The sheets of the AZ31 alloy subjected to the cross-shear deformation showed a uniform fine microstructure (1.2 ± 0.1 μm) with weak basal textures. The fabricated sheets showed a simultaneous high ultimate tensile strength and elongation-to-failure, i.e., ~333 MPa and ~21%, respectively. These were explained based on the structural features evolved due to the cross-shear deformation by DSR. The high strength was attributed to the uniform fine microstructure, whereas the high ductility was explained based on the basal texture weakening. PMID:27406685

  17. Thermal Microstructural Stability of AZ31 Magnesium after Severe Plastic Deformation

    SciTech Connect

    Young, John P.; Askari, Hesam A.; Hovanski, Yuri; Heiden, Michael J.; Field, David P.

    2015-03-01

    Both equal channel angular pressing and friction stir processing have the ability to refine the grain size of twin roll cast AZ31 magnesium and potentially improve its superplastic properties. This work used isochronal and isothermal heat treatments to investigate the microstructural stability of twin roll cast, equal channel angular pressed and friction stir processed AZ31 magnesium. For both heat treatment conditions, it was found that the twin roll casted and equal channel angular pressed materials were more stable than the friction stir processed material. Calculations of the grain growth kinetics showed that severe plastic deformation processing decreased the activation energy for grain boundary motion with the equal channel angular pressed material having the greatest Q value of the severely plastically deformed materials and that increasing the tool travel speed of the friction stir processed material improved microstructural stability. The Hollomon-Jaffe parameter was found to be an accurate means of identifying the annealing conditions that will result in substantial grain growth and loss of potential superplastic properties in the severely plastically deformed materials. In addition, Humphreys’s model of cellular microstructural stability accurately predicted the relative microstructural stability of the severely plastically deformed materials and with some modification, closely predicted the maximum grain size ratio achieved by the severely plastically deformed materials.

  18. Forming of a super plastic sheet metal made of MgAZ31 alloy

    NASA Astrophysics Data System (ADS)

    Zaid, Adnan I. O.; Al-Matari, Mustafa A. A.; Nazzal, M. A. H.

    2016-08-01

    Metal forming industries are constantly looking for advanced innovation, economical and energy efficient techniques. Superplastic forming has a great potential to be one of those advanced forming methods. It is a near net shape forming process which uses a unique type of materials where elongation exceeds 200% during a controlled forming conditions, e.g. temperature, pressure, and strain rate. Most of superplastic materials are formed by gas technique at elevated temperature. The main objectives of the research work in this paper were: to study the effects of the forming schemes on the forming time and thickness distribution of the formed and device a method to improve the forming part thickness and its uniformity distribution and the forming time. In this paper, a hydraulic and heating system were designed and manufactured to facilitate the experimental investigation. The superplastic magnesium alloy AZ31, Mg AZ31, was formed at 350°C with different strain rates to investigate the effect of the forming pressure profiles on the thickness uniformity of the superplastic formed part. The pressure profiles were generated based on Dutta and Mukherjee analytical approach. Finally, a variable strain rate method is modified to improve the uniformity of the thickness distribution of the formed part and reduce the forming time; which is a major limitation of superplastic forming.

  19. Experimental investigation of anisotropy evolution of AZ31 magnesium alloy sheets under tensile loading

    SciTech Connect

    Tari, D. Ghaffari; Worswick, M. J.

    2011-05-04

    Increasing demand for lighter final products has created new opportunities for the application of new light weight materials. Due to high strength to density ratio and good magnetic resistance properties, magnesium alloys are good candidates to replace steel and aluminum for same application. However, limited numbers of active slip deformation mechanisms, result in a decreased formability at room temperature. Furthermore, wrought magnesium alloys have an initial crystallographic texture, remained from the prior rolling operations, which makes them highly anisotropic. In this paper, tensile tests are performed at room temperature and 200 deg. C at different strain rates and orientations relative to the rolling direction, including rolling, 30 deg., 45 deg., 60 deg. and transverse orientation. The strain rates adopted for these experiments varied from 0.001 to 1.0. The testing results show the effect of temperature on the strain rate sensitivity of AZ31 sheets. The extent of deformation is continuously recorded using two separate high temperature extensometers. The results of testing show an increase in the r-values with the plastic deformation. The strain rate sensitivity of AZ31 increased as the temperature was elevated. At higher strain rates the measured r-values are larger and the slope of its evolution with the plastic strain is steeper.

  20. Electrophoretic deposition of nanostructured hydroxyapatite coating on AZ91 magnesium alloy implants with different surface treatments

    NASA Astrophysics Data System (ADS)

    Rojaee, Ramin; Fathi, Mohammadhossein; Raeissi, Keyvan

    2013-11-01

    Bio-absorbable magnesium (Mg) based alloys have been introduced as innovative orthopedic implants during recent years. It has been specified that rapid degradation of Mg based alloys in physiological environment should be restrained in order to be utilized in orthopedic trauma fixation and vascular intervention. In this developing field of healthcare materials, micro-arc oxidation (MAO), and MgF2 conversion coating were exploited as surface pre-treatment of AZ91 magnesium alloy to generate a nanostructured hydroxyapatite (n-HAp) coating via electrophoretic deposition (EPD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) techniques were used to characterize the obtained powder and coatings. The potentiodynamic polarization tests were carried out to evaluate the corrosion behavior of the coated and uncoated specimens, and in vitro bioactivity evaluation were performed in simulated body fluid. Results revealed that the MAO/n-HAp coated AZ91 Mg alloy samples with a rough topography and lower corrosion current density leads to a lower Mg degradation rate accompanied by high bioactivity.

  1. Project W-151 Tank 101-AZ Waste Retrieval System Year 2000 Compliance Assessment Project Plan

    SciTech Connect

    BUSSELL, J.H.

    1999-08-02

    This assessment describes the potential Year 2000 (Y2K) problems and describes the methods for achieving Y2K compliance for Project W-151, Tank 101-AZ Waste Retrieval System. The purpose of this assessment is to give an overview of the project. This document will not be updated and any dates contained in this document are estimates and may change. Two mixer pumps and instrumentation have been or are planned to be installed in waste tank 101-AZ to demonstrate solids mobilization. The information and experience gained during this process test will provide data for comparison with sludge mobilization prediction models and provide indication of the effects of mixer pump operation on an Aging Waste Facility tank. A limited description of system dates, functions, interfaces, potential Y2K problems, and date resolutions is presented. The project is presently on hold, and definitive design and procurement have been completed. This assessment will describe the methods, protocols, and practices to ensure that equipment and systems do not have Y2K problems.

  2. SAFETY ANALYSIS FOR TANK 241-AZ-101 MIXER PUMP PROCESS TEST

    SciTech Connect

    HAMMOND DM; HARRIS JP; MOUETTE P

    1997-06-09

    This document contains the completed safety analysis which establishes the safety envelope for performing the mixer pump process test in Tank 241-AZ-101. This process test is described in TF-210-OTP-001. All equipment necessary for the mixer pump test has been installed by Project W-151. The purpose of this document is to describe and analyze the mixer pump test for Aging Waste Facility (AWF) Tank 241-AZ-101 and to address the 'yes/maybe' responses marked for evaluation questions identified in Unreviewed Safety Question Evaluation (USQE) TF-94-0266. The scope of this document is limited to the performance of the mixer pump test for Tank 241-AZ-101. Unreviewed Safety Question Determination (USQD) TF-96-0018 verified that the installation of two mixer pumps into Tank 241-AZ-101 was within the current Tank Waste Remediation System (TWRS) Authorization Basis. USQDs TF-96-0461, TF-96-0448, and TF-96-0805 verified that the installation of the in-tank video camera, thermocouples, and Ultrasonic Interface Level Analyzer (URSILLA), respectively, were within the current TWRS Authorization Basis. USQD TF-96-1041 verified that the checkout testing of the installed equipment was within the current TWRS Authorization Basis. Installation of the pumps and equipment has been completed. An evaluation of safety considerations associated with operation of the mixer pumps for the mixer pump test is provided in this document. This document augments the existing AWF authorization basis as defined in the Interim Safety Basis (Stahl 1997), and as such, will use the existing Interim Operational Safety Requirements (IOSRs) of Heubach 1996 to adequately control the mixer pump test. The hazard and accident analysis is limited to the scope and impact of the mixer pump test, and therefore does not address hazards already addressed by the current AWF authorization basis. This document does not evaluate removal of the mixer pumps. Safety considerations for removal of the pumps will be addressed by

  3. 76 FR 15936 - Designation for the Owensboro, KY; Bloomington, IL; Iowa Falls, IA; Casa Grande, AZ; Fargo, ND...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-22

    ... hours (7 CFR 1.27(c)). SUPPLEMENTARY INFORMATION: In the August 30, 2010, Federal Register (75 FR 52925..., IL; Iowa Falls, IA; Casa Grande, AZ; Fargo, ND; Grand Forks, ND; and Plainview, TX Areas AGENCY... Grand Forks, ND (701) 772-2414 4/1/2011 3/31/2014 Plainview Plainview, TX (806) 893-1364 4/1/2011...

  4. 77 FR 23496 - Notice of Relocation of the Bureau of Land Management's Tucson Field Office in Tucson, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Bureau of Land Management Notice of Relocation of the Bureau of Land Management's Tucson Field Office in Tucson, AZ AGENCY: Bureau of Land Management, Interior. ACTION: Notice of relocation. SUMMARY: This notice announces the relocation of the Bureau of Land Management's (BLM) Tucson Field Office (TFO)...

  5. Arsenic Removal from Drinking Water by Adsorptive Media USEPA Demonstration Project at Rimrock AZ Final Performance Evaluation Report

    EPA Science Inventory

    This report documents the activities performed during and the results obtained from the arsenic removal treatment technology demonstration project at the Arizona Water Company (AWC) facility in Rimrock, AZ. The objectives of the project were to evaluate: 1) the effectiveness of ...

  6. ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA, USEPA DEMONSTRATION PROJECT AT RIMROCK, AZ, SIX-MONTH EVALUATION REPORT

    EPA Science Inventory

    This report documents the activities performed during and the results obtained from the first six months of the arsenic removal treatment technology demonstration project at Rimrock, AZ. The objectives of the project are to evaluate the effectiveness of AdEdge Arsenic Package Uni...

  7. 77 FR 2957 - Foreign-Trade Zone 219-Yuma, AZ; Application for Reorganization and Expansion Under Alternative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-20

    ... Controls Battery Group, 3740 South Arizona Avenue, Yuma. In addition, the applicant is requesting that... Foreign-Trade Zones Board Foreign-Trade Zone 219--Yuma, AZ; Application for Reorganization and Expansion...) Board (the Board) by the Greater Yuma Economic Development Corporation, grantee of FTZ 219,...

  8. Warm Deep Drawing of Rectangular Parts of AZ31 Magnesium Alloy Sheet Adopting Variable Blank Holder Force

    NASA Astrophysics Data System (ADS)

    Ying-hong, Peng; Qun-feng, Chang; Da-yong, Li; Xiao-qin, Zeng

    2007-05-01

    AZ31 magnesium alloy sheet with good shape and formability is fabricated by warm cross rolling. Uniaxial tensile tests are conducted using a Gleeble 3500 thermal - mechanical simulator, and the mechanical properties of AZ31 magnesium alloy sheet are analyzed. A warm deep drawing process of square part is also simulated by the finite element method. The influences of blank holder force on the formability are numerically investigated. A double-action hydraulic press that can realize adjustable blank holder forces is developed and its working principle and control system are introduced. Some warm deep drawing experiments of square parts of AZ31 magnesium alloy sheet are also performed. Different variation schemes of the blank holder force with the stroke of the punch are tested, and the experiment results are compared. Results show that the suitable blank holder force variation scheme is a ladder curve with the punch stroke. Adopting the variable blank holder force technique can improve 13.2% of the drawing depth of square parts of AZ31 magnesium alloy sheet.

  9. Electrochemical Investigations of Polycaprolactone-Coated AZ31 Mg Alloy in Earle's Balance Salt Solution and Conventional Simulated Body Fluid

    NASA Astrophysics Data System (ADS)

    Wilke, Benjamin M.; Zhang, Lei

    2016-06-01

    Polycaprolactone (PCL) coating has been shown to increase the corrosion resistance of magnesium alloys when exposed to a simulated body fluid. A PCL dip coating was applied to AZ31 Mg alloy. Samples were immersed in both Earle's Balance Salt Solution (EBSS) and conventional simulated body fluids (c-SBF) up to 14 days. Microscopic morphology, electrochemical impedance spectroscopy, and potentiodynamic polarization tests were performed to evaluate the corrosion behavior changes of PCL coatings against immersion times in EBSS and c-SBF as compared to the uncoated AZ31 substrate. PCL-coated samples demonstrated improved corrosion resistance compared to bare AZ31 in both EBSS and c-SBF, indicating that the PCL coating exhibited good corrosion protection of AZ31 in simulated body fluid. Samples immersed in EBSS showed significantly higher electrochemical impedance values and slower corrosion progression as compared to the samples in c-SBF, because of the decreased chloride content and CO2 buffering mechanism of the EBSS.

  10. ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA. USEPA DEMONSTRATION PROJECT AT VALLEY VISTA, AZ FINAL PERFORMANCE EVALUATION REPORT

    EPA Science Inventory

    This report documents the activities performed during and the results obtained from the arsenic removal treatment technology demonstration project at an Arizona Water Company (AWC) facility in Sedona, AZ, commonly referred to as Valley Vista. The objectives of the project were t...

  11. 78 FR 53477 - Notice of Relocation of the Bureau of Land Management's San Pedro Project Office in Sierra Vista, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... Bureau of Land Management Notice of Relocation of the Bureau of Land Management's San Pedro Project Office in Sierra Vista, AZ AGENCY: Bureau of Land Management, Interior. ACTION: Notice. SUMMARY: This notice announces the relocation of the Bureau of Land Management's (BLM) San Pedro Project Office...

  12. ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA USEPA DEMONSTRATION PROJECT AT VALLEY VISTA, AZ SIX-MONTH EVALUATION REPORT

    EPA Science Inventory

    This report documents the activities performed and the results obtained from the first six months of the EPA arsenic removal technology demonstration project at the Arizona Water Company (AWC) facility in Sedona, AZ, commonly referred to as Valley Vista. The main objective of the...

  13. Pump Jet Mixing and Pipeline Transfer Assessment for High-Activity Radioactive Wastes in Hanford Tank 241-AZ-102

    SciTech Connect

    Y Onishi; KP Recknagle; BE Wells

    2000-08-09

    The authors evaluated how well two 300-hp mixer pumps would mix solid and liquid radioactive wastes stored in Hanford double-shell Tank 241-AZ-102 (AZ-102) and confirmed the adequacy of a three-inch (7.6-cm) pipeline system to transfer the resulting mixed waste slurry to the AP Tank Farm and a planned waste treatment (vitrification) plant on the Hanford Site. Tank AZ-102 contains 854,000 gallons (3,230 m{sup 3}) of supernatant liquid and 95,000 gallons (360 m{sup 3}) of sludge made up of aging waste (or neutralized current acid waste). The study comprises three assessments: waste chemistry, pump jet mixing, and pipeline transfer. The waste chemical modeling assessment indicates that the sludge, consisting of the solids and interstitial solution, and the supernatant liquid are basically in an equilibrium condition. Thus, pump jet mixing would not cause much solids precipitation and dissolution, only 1.5% or less of the total AZ-102 sludge. The pump jet mixing modeling indicates that two 300-hp mixer pumps would mobilize up to about 23 ft (7.0 m) of the sludge nearest the pump but would not erode the waste within seven inches (0.18 m) of the tank bottom. This results in about half of the sludge being uniformly mixed in the tank and the other half being unmixed (not eroded) at the tank bottom.

  14. 78 FR 43850 - Opportunity for Designation in Owensboro, KY; Bloomington, IL; Iowa Falls, IA; Casa Grande, AZ...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    ...; Bloomington, IL; Iowa Falls, IA; Casa Grande, AZ; Fargo, ND; Grand Forks, ND and Plainview, TX; Areas; Request for Comments on the Official Agencies Servicing These Areas AGENCY: Grain Inspection, Packers and... official services in the areas presently served by these agencies to submit an application for...

  15. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Pt. 91, SFAR No. 50-2 Special Federal Aviation...

  16. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Pt. 91, SFAR No. 50-2 Special Federal Aviation...

  17. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Pt. 91, SFAR No. 50-2 Special Federal Aviation...

  18. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Pt. 91, SFAR No. 50-2 Special Federal Aviation...

  19. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Pt. 91, SFAR No. 50-2 Special Federal Aviation...

  20. Weldability of A7075-T651 and AZ31B dissimilar alloys by MIG welding method based on welding appearances

    NASA Astrophysics Data System (ADS)

    Ishak, M.; Islam, M. R.

    2014-04-01

    It is not recommended to weld aluminium and magnesium dissimilar alloys using fusion welding method because of the formation of AlmMgn type intermetallic brittle compounds like Mg2Al3, Mg17Al12 etc. in the welding joint. These brittle compounds deteriorate the mechanical properties of the joint. But so far, insufficient researches have been attempted to stop the formation of AlmMgn type intermetallic brittle compounds in fusion welding method. The aim of this research work was to investigate on the weldability between A7075-T651 and AZ31B dissimilar alloys based on welding appearances and study the formation of intermetallic brittle compounds at the joint. In this research, A7075-T651 and AZ31B alloys were welded using ER5356 filler wire in MIG welding method in butt configuration. 100% argon was used as shielding gas. The results showed that, most of the welding appearances were moderate. The macroscopic investigation at all welding cross section showed that a lot of AlmMgn intermetallic brittle compounds were formed at the interface between weld seam and AZ31B parent metal side which caused macro cracks. A good number of macro pores were also observed at AZ31B parent metal side. These cracks and pores could easily cause the failure of the joint at very low stress.

  1. Brightness Variation and Companion Analysis of AZ Capricorni --- A Low-Mass Member in the Beta Pictoris Moving Group

    NASA Astrophysics Data System (ADS)

    Chen, Chang Yao; Chen, Wen-Ping

    2015-08-01

    AZ Capricorni (BD-17o 6128) is a low-mass member of the Beta Pictoris moving group, which consists of 55 known stellar systems sharing similar space moving motion as that of Beta Pic, the prototypical star with a prominent planetary debris disk. AZ Cap is a known X-ray source signifying its chromospheric activity. We present the three-year light curve of the star from 2010 to 2012. The 3.4 d period previously reported (Messina et al. 2010) is confirmed. The star was particularly active in 2011 with amplified brightness modulation. AZ Cap is known to have a close companion (Neuhäuser et al. 2002), which not only may confuse the X-ray source identification but, if bound to AZ Cap, would add to the inventory of the group membership. Astrometric measurements of DSS images, Pan-STARRS 1 images, and images taken by ourselves, at three epochs spanning 60 years, led to the conclusion that it is not a physical pair.

  2. Effect of microalloying on microstructure and hot working behavior for AZ31 based magnesium alloy

    NASA Astrophysics Data System (ADS)

    Shang, Lihong

    The formability of Mg alloy sheet in the as-hot rolled condition depends on the microstructure developed during hot rolling. In general, the formability of Mg alloys is improved by finer grain sizes. 'Microalloying' levels of calcium (Ca), strontium (Sr), and cerium (Ce) have been found to refine the as-cast structure, but there is no information as to whether this effect will be reflected in the as-hot worked structure and formability. Thus, in this work, the effects of microalloying levels of calcium (Ca), strontium (Sr), and cerium (Ce) on the microstructures (from as-cast to as-hot rolled) and subsequent hot deformation behavior of AZ31, nominally 3% Al, 1% Zn, and 0.3%Mn, were systematically investigated. To include the effect of solidification rate these alloys were cast in different moulds (preheated steel mould, Cu-mould, and water cooled Cu-mould). One-hit compression testing at temperatures between 250°C ˜ 400 °C, strain rates of 0.001, 0.01, 0.1 s-1 and strains from 0.2 up to 1.0, was performed to investigate the basic hot compression behavior, while two-hit compression testing was conducted to determine the static softening behavior. Hot rolling of the microalloyed AZ31 alloys was then carried out to study the effects of microalloying on as-hot rolled structure under two sets of rolling schedules. To investigate the formability of these microalloyed sheets, tensile tests were completed over a temperature range between ambient and 450°C, at strain rates between 0.1 and 0.0003 s-1. Results show that Ca and Sr act to refine the as cast grain size and the second phases, consistently promoting fine and uniform as-hot rolled grain structure. With regard to grain refinement, calcium has the strongest effect, whereas Ce is most effective for second phase refinement. In addition, microalloying retards grain growth during hot tensile testing. Multiple alloying presents a combined and complementary effect. A refined and uniform grain structure combined with

  3. AZ-101 Mixer Pump Demonstration and Tests Data Management Analysis Plan

    SciTech Connect

    DOUGLAS, D.G.

    2000-02-22

    This document provides a plan for the analysis of the data collected during the AZ-101 Mixer Pump Demonstration and Tests. This document was prepared after a review of the AZ-101 Mixer Pump Test Plan (Revision 4) [1] and other materials. The plan emphasizes a structured and well-ordered approach towards handling and examining the data. This plan presumes that the data will be collected and organized into a unified body of data, well annotated and bearing the date and time of each record. The analysis of this data will follow a methodical series of steps that are focused on well-defined objectives. Section 2 of this plan describes how the data analysis will proceed from the real-time monitoring of some of the key sensor data to the final analysis of the three-dimensional distribution of suspended solids. This section also identifies the various sensors or sensor systems and associates them with the various functions they serve during the test program. Section 3 provides an overview of the objectives of the AZ-101 test program and describes the data that will be analyzed to support that test. The objectives are: (1) to demonstrate that the mixer pumps can be operated within the operating requirements; (2) to demonstrate that the mixer pumps can mobilize the sludge in sufficient quantities to provide feed to the private contractor facility, and (3) to determine if the in-tank instrumentation is sufficient to monitor sludge mobilization and mixer pump operation. Section 3 also describes the interim analysis that organizes the data during the test, so the analysis can be more readily accomplished. Section 4 describes the spatial orientation of the various sensors in the tank. This section is useful in visualizing the relationship of the Sensors in terms of their location in the tank and how the data from these sensors may be related to the data from other sensors. Section 5 provides a summary of the various analyses that will be performed on the data during the test

  4. Proximity of H2A.Z containing nucleosome to the transcription start site influences gene expression levels in the mammalian liver and brain

    PubMed Central

    Bargaje, Rhishikesh; Alam, Mohammad Parwez; Patowary, Ashok; Sarkar, Maharnob; Ali, Tamer; Gupta, Shivani; Garg, Manali; Singh, Meghna; Purkanti, Ramya; Scaria, Vinod; Sivasubbu, Sridhar; Brahmachari, Vani; Pillai, Beena

    2012-01-01

    Nucleosome positioning maps of several organisms have shown that Transcription Start Sites (TSSs) are marked by nucleosome depleted regions flanked by strongly positioned nucleosomes. Using genome-wide nucleosome maps and histone variant occupancy in the mouse liver, we show that the majority of genes were associated with a single prominent H2A.Z containing nucleosome in their promoter region. We classified genes into clusters depending on the proximity of H2A.Z to the TSS. The genes with no detectable H2A.Z showed lowest expression level, whereas H2A.Z was positioned closer to the TSS of genes with higher expression levels. We confirmed this relation between the proximity of H2A.Z and expression level in the brain. The proximity of histone variant H2A.Z, but not H3.3 to the TSS, over seven consecutive nucleosomes, was correlated with expression. Further, a nucleosome was positioned over the TSS of silenced genes while it was displaced to expose the TSS in highly expressed genes. Our results suggest that gene expression levels in vivo are determined by accessibility of the TSS and proximity of H2A.Z. PMID:22821566

  5. Wear Resistance of AZ91D Magnesium Alloy with and Without Microarc Oxidation Coating and Ti6Al4V Alloy in Artificial Saliva

    NASA Astrophysics Data System (ADS)

    Zhang, X. P.; Zou, Y. S.; Wu, F. M.; Zhao, Z. P.; You, L.; Gu, C. F.; Liao, Y. Z.

    The wear resistances of AZ91D magnesium alloy with and without microarc oxidation (MAO) coating and Ti6Al4V alloy in artificial saliva were investigated at room temperature. The wear resistance of AZ91D magnesium alloy in artificial saliva was significantly improved after microarc oxidation treatment. The volume loss of untreated AZ91D magnesium alloy sample was 20.95 times of that of AZ91D magnesium alloy with MAO coating, and that of Ti6Al4V was 5.42 times of that of MAO. Furthermore, the wear resistance of AZ91D magnesium alloy was lower than that of Ti6Al4V alloy in artificial saliva. The wear mechanisms of AZ91D magnesium and Ti6Al4V were discussed. It was found that the wear mechanism of the MAO was associated with abrasion and microfracture. There were two dominative wear mechanisms for AZ91D alloy and Ti6Al4V alloy under the loading conditions used in the experiment, namely, micro-machining wear and deformation-induced wear.

  6. USP10 deubiquitylates the histone variant H2A.Z and both are required for androgen receptor-mediated gene activation.

    PubMed

    Draker, Ryan; Sarcinella, Elizabeth; Cheung, Peter

    2011-05-01

    H2A.Z, a variant of H2A, is found at the promoters of inducible genes in both yeast and higher eukaryotes. However, its role in transcriptional regulation is complex since it has been reported to function both as a repressor and activator. We have previously found that mono-ubiquitylation of H2A.Z is linked to transcriptional silencing. Here, we provide new evidence linking H2A.Z deubiquitylation to transcription activation. We found that H2A.Z and ubiquitin-specific protease 10 (USP10) are each required for transcriptional activation of the androgen receptor (AR)-regulated PSA and KLK3 genes. USP10 directly deubiquitylates H2A.Z in vitro and in vivo, and reducing USP10 expression in prostate cancer cells results in elevated steady-state levels of mono-ubiquitylated H2A.Z (H2A.Zub1). Moreover, knockdown of USP10 ablates hormone-induced deubiquitylation of chromatin proteins at the AR-regulated genes. Finally, by sequential ChIP assays, we found that H2A.Zub1 is enriched at the PSA and KLK3 regulatory regions, and loss of H2A.Zub1 is associated with transcriptional activation of these genes. Together, these data provide novel insights into how H2A.Z ubiquitylation/deubiquitylation and USP10 function in AR-regulated gene expression.

  7. Chromatin Remodeling by Imitation Switch (ISWI) Class ATP-dependent Remodelers Is Stimulated by Histone Variant H2A.Z

    PubMed Central

    Goldman, Joseph A.; Garlick, Joseph D.; Kingston, Robert E.

    2010-01-01

    ATP-dependent chromatin remodeling complexes rearrange nucleosomes by altering the position of DNA around the histone octamer. Although chromatin remodelers and the histone variant H2A.Z colocalize on transcriptional control regions, whether H2A.Z directly affects remodeler association or activity is unclear. We determined the relative association of remodelers with H2A.Z chromatin and tested whether replacement of H2A.Z in a nucleosome altered the activity of remodeling enzymes. Many families of remodelers showed increased association with H2A.Z chromatin, but only the ISWI family of chromatin remodelers showed stimulated activity in vitro. An acidic patch on the nucleosome surface, extended by inclusion of H2A.Z in nucleosomes and essential for viability, is required for ISWI stimulation. We conclude that H2A.Z incorporation increases nucleosome remodeling activity of the largest class of mammalian remodelers (ISWI) and that it correlates with increased association of other remodelers to chromatin. This reveals two possible modes for regulation of a remodeler by a histone variant. PMID:19940112

  8. Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant.

    PubMed

    Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Collins, Boyce; Badve, Aditya; Dong, Zhongyun; Park, Chanhee; Kim, Cheol Sang; Sankar, Jagannathan; Yun, Yeoheung

    2014-12-01

    This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test.

  9. 26. 'CITY HOSPITAL, BLACKWELL'S ISLAND.' (Source: New York City Department ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. 'CITY HOSPITAL, BLACKWELL'S ISLAND.' (Source: New York City Department of Public Finance, Real Estate Owned by the City of New York under Jurisdiction of the Department of Public Charities, 1909.) - Island Hospital, Roosevelt Island, New York County, NY

  10. Build a City.

    ERIC Educational Resources Information Center

    Reynolds, Jean A.

    1985-01-01

    A week-long build-a-city project is described which lets students become familiar with the history of the five Platonic solids (tetrahedron, octahedron, hexahedron, isosahedron, dodecahedron) and then use these solids to create a city using posterboard and construction paper. (MNS)

  11. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

    ... backdrops for the 2002 Winter Olympics, to be held in Salt Lake City, Utah. The mountains surrounding Salt Lake City are renowned for ... western edge of the Rocky Mountains and eastern rim of the Great Basin. This early-winter image pair was acquired by the Multi-angle ...

  12. The Industrial City

    ERIC Educational Resources Information Center

    Mohl, Raymond

    1976-01-01

    This article, the sixth installment in Environment's "Looking Back" series, traces the woes of America's industrialized cities to the movement that developed cities primarily as centers for industrial enterprise rather than as places for people to live. Today's social ills, from pollution to poverty, developed from that movement. (BT)

  13. CITY III Operator's Manual.

    ERIC Educational Resources Information Center

    Envirometrics, Inc., Washington, DC.

    CITY III is a computer-assisted simulation game of an urban system involving player operation of and interaction with economic, social, and government components. The role of operator in the game is to take the handwritten inputs (decisions) from the CITY III participants, process them, and return output which initiates the next round of…

  14. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  15. Innovation and the City

    ERIC Educational Resources Information Center

    Kleiman, Neil; Forman, Adam; Ko, Jae; Giles, David; Bowles, Jonathan

    2013-01-01

    With Washington trapped in budget battles and partisan gridlock, cities have emerged as the best source of government innovation. Nowhere is this more visible than in New York City. Since taking office in 2002, Mayor Bloomberg has introduced a steady stream of innovative policies, from a competition to recruit a new applied sciences campus and a…

  16. Walkout in Crystal City

    ERIC Educational Resources Information Center

    Barrios, Greg

    2009-01-01

    When students take action, they create change that extends far beyond the classroom. In this article, the author, who was a former teacher from Crystal City, Texas, remembers the student walkout that helped launch the Latino civil rights movement 40 years ago. The Crystal City student walkout remains a high point in the history of student activism…

  17. Stress-based crystal analysis of yielding in rolled Mg AZ31B

    NASA Astrophysics Data System (ADS)

    Lloyd, J. T.; Becker, R.

    2016-02-01

    A stress-based analysis is demonstrated that can be used to evaluate the effect of material orientation and loading conditions on the micro- and macro-scale yield response of strongly textured metals. This analysis is used to construct microscale yield surfaces for selected deformation mechanisms in rolled AZ31B. Two-dimensional projections of these surfaces are plotted along sample directions to quantify the relative activity of each mechanism for various loading conditions. By assigning each mechanism realistic strengths, the analysis is used to quantify the influence of each deformation mechanism on macroscale yield behaviour. Due to its simplicity, this analysis can be easily carried out to probe and visualize projections of material response in any part of stress space given the material's texture, its relevant deformation mechanisms and realistic initial strengths of these mechanisms.

  18. Laser beam welding of AZ31B-H24 magnesium alloy.

    SciTech Connect

    Leong, K. H.

    1998-09-29

    The laser beam weldability of AZ31B magnesium alloy was examined with high power CW CO{sub 2} and pulsed Nd:YAG lasers. The low viscosity and surface tension of the melt pool make magnesium more difficult to weld than steel. Welding parameters necessary to obtain good welds were determined for both CW CO{sub 2} and pulsed Nd:YAG lasers. The weldability of the magnesium alloy was significantly better with the Nd:YAG laser. The cause of this improvement was attributed to the higher absorption of the Nd:YAG beam. A lower threshold beam irradiance was required for welding, and a more stable weldpool was obtained.

  19. Effects of Microstructure and Processing Methods on Creep Behavior of AZ91 Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Shahbeigi Roodposhti, Peiman; Sarkar, Apu; Murty, Korukonda L.; Scattergood, Ronald O.

    2016-09-01

    This review sheds light on the creep properties of AZ91 magnesium alloys with a major emphasis on the influence of microstructure on the creep resistance and underlying creep deformation mechanism based on stress exponent and activation energy. Effects of processing routes such as steel mold casting, die casting, and thixoforming are considered. Roles of a wide range of additional alloying elements such as Si, Sb, Bi, Ca, Sn, REs, and combined addition of them on the microstructure modification were investigated. The reaction between these elements and the Mg or Al in the matrix develops some thermally stable intermetallic phases which improves the creep resistance at elevated temperatures, however does not influence the creep mechanism.

  20. AZ-101 Mixer Pump Test MT Fury Suspended Solids Profiler Application and Testing

    SciTech Connect

    MACLEAN, G.T.

    2000-01-06

    Describes the radiation testing and calibration of the AZ-101 tank suspended solids profiler unit mounted on 6 tank riser 24A. The Mt. Fury Suspended Solids Profiler (SSP) is a microprocessor-controlled instrument that measures the turbidity of solid-liquid suspensions and sludges. The profiler is used commercially for the monitoring and control of clarifiers and thickeners in waste treatment, mining, pulp and paper, and other industrial processing facilities. The instrument includes a three inch diameter probe, a Kynar coated coaxial cable, a reel assembly with a clutch and drive shaft, a stepper motor, and electronics. The instrument measures insoluble or suspended solids content in liquids by transmitting infrared energy at a wavelength of 935 nm and measuring the extent of backscatter. This frequency is not affected by solution color. There are two detectors that allow the instrument to operate over a broad range of concentrations, from clear liquids to light sludges.

  1. Optimization of Wear Behavior of Magnesium Alloy AZ91 Hybrid Composites Using Taguchi Experimental Design

    NASA Astrophysics Data System (ADS)

    Girish, B. M.; Satish, B. M.; Sarapure, Sadanand; Basawaraj

    2016-06-01

    In the present paper, the statistical investigation on wear behavior of magnesium alloy (AZ91) hybrid metal matrix composites using Taguchi technique has been reported. The composites were reinforced with SiC and graphite particles of average size 37 μm. The specimens were processed by stir casting route. Dry sliding wear of the hybrid composites were tested on a pin-on-disk tribometer under dry conditions at different normal loads (20, 40, and 60 N), sliding speeds (1.047, 1.57, and 2.09 m/s), and composition (1, 2, and 3 wt pct of each of SiC and graphite). The design of experiments approach using Taguchi technique was employed to statistically analyze the wear behavior of hybrid composites. Signal-to-noise ratio and analysis of variance were used to investigate the influence of the parameters on the wear rate.

  2. Simulation of cylindrical cup drawing of AZ31 sheet metal with crystal plasticity finite element method

    NASA Astrophysics Data System (ADS)

    Tang, Weiqin; Li, Dayong; Zhang, Shaorui; Peng, Yinghong

    2013-12-01

    As a light-weight structural material, magnesium alloys show good potential in improving the fuel efficiency of vehicles and reducing CO2 emissions. However, it is well known that polycrystalline Mg alloys develop pronounced crystallographic texture and plastic anisotropy during rolling, which leads to earing phenomenon during deep drawing of the rolled sheets. It is vital to predict this phenomenon accurately for application of magnesium sheet metals. In the present study, a crystal plasticity model for AZ31 magnesium alloy that incorporates both slip and twinning is established. Then the crystal plasticity model is implemented in the commercial finite element software ABAQUS/Explicit through secondary development interface (VUMAT). Finally, the stamping process of a cylindrical cup is simulated using the developed crystal plasticity finite element model, and the predicting method is verified by comparing with experimental results from both earing profile and deformation texture.

  3. Spectral properties of the extreme solar system objects 2012 DR30 and 2013 AZ60

    NASA Astrophysics Data System (ADS)

    Szabo, G.; Kiss, Cs.; Duffard, R.; Pinilla-Alonso, N.; Licandro, J.

    2014-04-01

    2012 DR30 and 2013 AZ60 represent two examples of TNOs with very large aphelion distances (2405 and 1951 AU, respectively), thus standing for the currently best candidates of possible scattered-in Oort-cloud objects. Though they possibly shared a similar dynamical scenario, the two bodies exhibit surprisingly diverging prediction for orbital evolution and also quite different surface properties (Kiss et al. 2013, Kiss et al. 2014). Here we compare these optical and infrared photometry and spectra of the two bodies. Both show a generaly flat spectrum, but with significantly differing slope. We find clear signs of water ice on 2013 DR30 particulary, which is an exciting diagnostic of a possible water reservoir at very large perihelion distances, and on the other hand, suggests a close link between the giant cometary nuclei of the Oort Cloud (for that Hale-Bopp is the only known example in our Solar System) and these exotic TNOs.

  4. Low temperature superplasticity of AZ91 magnesium alloy with non-equilibrium grain boundaries

    SciTech Connect

    Mabuchi, M.; Ameyama, K.; Iwasaki, H.; Higashi, K.

    1999-05-28

    The superplastic behavior of a fine-grained AZ91 alloy, processed by equal channel angular extrusion, has been investigated in a low temperature range of 423--523 K. The experimental results showed a stress exponent of 2 and the activation energy for superplastic flow was in agreement with that for grain boundary diffusion of magnesium. The alloy with non-equilibrium grain boundary structures exhibited lower superplastic elongation than the alloy with equilibrium grain boundaries. Furthermore, the strain rate for superplastic flow of the former was lower than that of the latter. These differences probably arise because the accommodation process for grain boundary sliding is hampered by the long-range stresses associated with the non-equilibrium grain boundaries.

  5. Preparation of Composite Coating on AZ91D Magnesium Alloy by Silica Sol-Micro Oxidation

    NASA Astrophysics Data System (ADS)

    Shao, Zhongcai; Zhang, Feifei; Zhao, Ruiqiang; Shen, Xiaoyi

    2016-03-01

    Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol-gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO2 gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.

  6. Microstructure and interfacial reactions of soldering magnesium alloy AZ31B

    SciTech Connect

    Liu Liming; Wu Zhonghui

    2010-01-15

    In this paper, economic and innoxious solder alloys with low melting temperature were designed for AZ31B. Their chemical composition and relevant parameters were investigated for a high-performance structure of bonding region. Results of microstructure observation showed that Zn-enriched phases disappeared and {alpha}-Mg existed in the joints in the form of coarse dendrites by increasing the concentration of Mg in the solder alloys. Water cooling with a high cooling rate was adopted in experiments. Experimental research showed that high cooling rate restricted the grains of {alpha}-Mg as the equiaxed dendrites, which was about 1/5 of the coarse dendrite but their number was more than 40-50 times. Both morphology with typical fracture and the analysis on X-ray diffraction fracture indicated that equiaxed dendrites significantly improved the mechanical property of the joints. Necking phenomenon occurred in the bonding region was in favor of the improvement of joint shear strength.

  7. Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting

    SciTech Connect

    Cavaliere, P. . E-mail: pasquale.cavaliere@unile.it; De Marco, P.P.

    2007-03-15

    The room temperature fatigue properties of AZ91 magnesium alloy produced by high pressure die casting (HPDC) as cast, heat treated, friction stir processed (FSP) and FSP and heat treated were studied. The fatigue properties of the material were evaluated for the HPDC magnesium alloy in the as-received state and after a solution treatment at 415 deg. C for 2 h and an ageing treatment at 220 deg. C for 4 h. The heat treatment resulted in a significant increase in the fatigue properties of the HPDC material, while no significance influence of heat treatment was recorded in the FSP condition. The morphology of fracture surfaces was examined by employing a field emission gun scanning electron microscope (FEGSEM)

  8. Statistical analysis on static recrystallization texture evolution in cold-rolled AZ31 magnesium alloy sheet.

    PubMed

    Park, Jun-Ho; Ahn, Tae-Hong; Choi, Hyun-Sik; Chung, Jung-Man; Kim, Dong-Ik; Oh, Kyu Hwan; Han, Heung Nam

    2013-08-01

    Cast AZ31B-H24 magnesium alloy, comprising Mg with 3.27 wt% Al and 0.96 wt% Zn, was cold rolled and subsequently annealed. Global texture evolutions in the specimens were observed by X-ray diffractometry after the thermomechanical processing. Image-based microstructure and texture for the deformed, recrystallized, and grown grains were observed by electron backscattered diffractometry. Recrystallized grains could be distinguished from deformed ones by analyzing grain orientation spread. Split basal texture of ca. ±10-15° in the rolling direction was observed in the cold-rolled sample. Recrystallized grains had widely spread basal poles at nucleation stage; strong {0001} basal texture developed with grain growth during annealing.

  9. Damage and Failure Analysis of AZ31 Alloy Sheet in Warm Stamping Processes

    NASA Astrophysics Data System (ADS)

    Zhao, P. J.; Chen, Z. H.; Dong, C. F.

    2016-07-01

    In this study, a combined experimental-numerical investigation on the failure of AZ31 Mg alloy sheet in the warm stamping process was carried out based on modified GTN damage model which integrated Yld2000 anisotropic yield criterion. The constitutive equations of material were implemented into a VUMAT subroutine for solver ABAQUS/Explicit and applied to the formability analysis of mobile phone shell. The morphology near the crack area was observed using SEM, and the anisotropic damage evolution at various temperatures was simulated. The distributions of plastic strain, damage evolution, thickness, and fracture initiation obtained from FE simulation were analyzed. The corresponding forming limit diagrams were worked out, and the comparison with the experimental data showed a good agreement.

  10. Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site

    SciTech Connect

    ANANTATMULA, R.P.

    1999-10-20

    In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except for the time period between 1980 and 1987, impressed current cathodic protection has been applied to the pipe since its installation in 1974. The paper describes the history of the cracking of the pipe, the probable cracking mechanisms, and the recommended future action for repair/replacement of the pipe.

  11. Effect of preheat on TIG welding of AZ61 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Xu, Nan

    2012-04-01

    The effects of preheat treatments on the microstructures and mechanical properties of tungsten inert gas (TIG)-welded AZ61 magnesium alloy joints were studied by microstructural observations, microhardness tests and tensile tests. The results showed that the volume fraction of the lamellar β-Mg17(Al,Zn)12 intermetallic compound of in fusion zone (FZ) increased from 15% to 66% with an increase in preheat temperature. Moreover, the microhardness of the FZ and the ultimate tensile strength of the welded joints reached their maximum values when the preheat temperature was 300°C because more lamellar β-Mg17(Al,Zn)12 intermetallic compounds were distributed at the α-Mg grain boundaries and no cracks and pores formed in the FZ of the welded joint.

  12. Process Influences on Laser-beam Melting of the Magnesium Alloy AZ91

    NASA Astrophysics Data System (ADS)

    Schmid, Dominik; Renza, Johanna; Zaeh, Michael F.; Glasschroeder, Johannes

    Magnesium's great lightweight potential and high biocompatibility render laser-beam melting of this metal increasingly interesting. Despite recent research activities in this field, the properties thereby achieved are still inadequate for industrial or medical use. Low surface quality caused by powder sintered to parts' boundaries is one of the main problems. This effect is discussed theoretically and examined on single tracks of the magnesium alloy AZ91. Welding-penetration depth and width was measured on a magnesium plate with and without a powder layer. For the derivation of suitable process parameters, structures with incrementally increasing hatch distances were built and microscopically analyzed. The influence on defect percentage and hardness of the parts was determined based on specimens manufactured with different layer thicknesses. The influence of the oxygen content on solids was analyzed by varying the process atmosphere.

  13. Archaeological studies at Drill Hole U20az Pahute Mesa, Nye county, Nevada. [Contains bibliography

    SciTech Connect

    Simmons, A.H.; Hemphill, M.L.; Henton, G.H.; Lockett, C.L.; Nials, F.L.; Pippin, L.C.; Walsh, L.

    1991-07-01

    During the summer of 1987, the Quaternary Sciences Center (formerly Social Science Center) of the Desert Research Institute (DRI), University of Nevada System, conducted data recovery investigations at five archaeological sites located near Drill Hole U20az on the Nevada Test Site in southern Nevada. These sites were among 12 recorded earlier during an archaeological survey of the drill hole conducted as part of the environmental compliance activities of the Department of Energy (DOE). The five sites discussed in this report were considered eligible for the National Register of Historic Places and were in danger of being adversely impacted by construction activities or by effects of the proposed underground nuclear test. Avoidance of these sites was not a feasible alternative; thus DRI undertook a data recovery program to mitigate expected adverse impacts. DRI's research plan included controlled surface collections and excavation of the five sites in question, and had the concurrence of the Nevada Division of Historic Preservation and Archaeology and the Advisory Council of Historic Preservation. Of the five sites investigated, the largest and most complex, 26Ny5207, consists of at least three discrete artifact concentrations. Sites 26Ny5211 and 26Ny5215, both yielded considerable assemblages. Site 26Ny5206 is very small and probably is linked to 26Ny5207. Site 26Ny5205 contained a limited artifact assemblage. All of the sites were open-air occurrences, and, with one exception contained no or limited subsurface cultural deposits. Only two radiocarbon dates were obtained, both from 26Ny5207 and both relatively recent. While the investigations reported in the volume mitigate most of the adverse impacts from DOE activities at Drill Hole U20az, significant archaeological sites may still exist in the general vicinity. Should the DOE conduct further activities in the region, additional cultural resource investigations may be required. 132 refs., 71 figs., 44 tabs.

  14. Heat Treatment of AZ91D Mg-Al-Zn Alloy: Microstructural Evolution and Dynamic Response

    NASA Astrophysics Data System (ADS)

    Luong, Dung D.; Shunmugasamy, Vasanth Chakravarthy; Cox, James; Gupta, Nikhil; Rohatgi, Pradeep K.

    2013-11-01

    Magnesium alloys are attracting great interest from the automotive industry because of the potential for weight reduction. An AZ91D cast alloy was studied in the current work to understand the effect of heat treatment on the microstructure and dynamic compressive properties. The selected heat treatments include solution treatment (T4) and solution treatment followed by aging (T6). The as-cast alloy microstructure consists of intermetallic β-phase (Mg17Al12) precipitates surrounded by α + β lamellar eutectic in α-Mg solid solution. The AZ91D-T4 specimens showed small β-phase precipitates along the grain boundaries and regions of eutectic mixture. The T6 heat treatment causes the β-phase platelets in the α + β eutectic to grow and develop into β-precipitates. The difference in the phase morphology reflects into the mechanical properties. The Vickers hardness of the T6 heat-treated specimens was 3.6% higher than the as-cast alloy. The compressive yield strengths of T4 and T6 treated specimens were 1.3% and 43.1% higher than those of as-cast specimens. The high strain rate compression testing resulted in increase in the strength with strain rate for the T4 and T6 specimens. A maximum increase of 42% was observed in T6 specimen tested at a strain rate of 4,000/s in comparison to the quasi-static compression. Under high strain rate compression testing, the T6 heat-treated specimens showed failure of the β-precipitates resulting in increased energy absorption in comparison to the quasi-static compression.

  15. Inequality and City Size*

    PubMed Central

    Baum-Snow, Nathaniel; Pavan, Ronni

    2013-01-01

    Between 1979 and 2007 a strong positive monotonic relationship between wage inequality and city size has developed. This paper investigates the links between this emergent city size inequality premium and the contemporaneous nationwide increase in wage inequality. After controlling for the skill composition of the workforce across cities of different sizes, we show that at least 23 percent of the overall increase in the variance of log hourly wages in the United States from 1979 to 2007 is explained by the more rapid growth in the variance of log wages in larger locations relative to smaller locations. This influence occurred throughout the wage distribution and was most prevalent during the 1990s. More rapid growth in within skill group inequality in larger cities has been by far the most important force driving these city size specific patterns in the data. Differences in the industrial composition of cities of different sizes explain up to one-third of this city size effect. These results suggest an important role for agglomeration economies in generating changes in the wage structure during the study period. PMID:24954958

  16. Great cities look small.

    PubMed

    Sim, Aaron; Yaliraki, Sophia N; Barahona, Mauricio; Stumpf, Michael P H

    2015-08-01

    Great cities connect people; failed cities isolate people. Despite the fundamental importance of physical, face-to-face social ties in the functioning of cities, these connectivity networks are not explicitly observed in their entirety. Attempts at estimating them often rely on unrealistic over-simplifications such as the assumption of spatial homogeneity. Here we propose a mathematical model of human interactions in terms of a local strategy of maximizing the number of beneficial connections attainable under the constraint of limited individual travelling-time budgets. By incorporating census and openly available online multi-modal transport data, we are able to characterize the connectivity of geometrically and topologically complex cities. Beyond providing a candidate measure of greatness, this model allows one to quantify and assess the impact of transport developments, population growth, and other infrastructure and demographic changes on a city. Supported by validations of gross domestic product and human immunodeficiency virus infection rates across US metropolitan areas, we illustrate the effect of changes in local and city-wide connectivities by considering the economic impact of two contemporary inter- and intra-city transport developments in the UK: High Speed 2 and London Crossrail. This derivation of the model suggests that the scaling of different urban indicators with population size has an explicitly mechanistic origin. PMID:26179988

  17. Great cities look small

    PubMed Central

    Sim, Aaron; Yaliraki, Sophia N.; Barahona, Mauricio; Stumpf, Michael P. H.

    2015-01-01

    Great cities connect people; failed cities isolate people. Despite the fundamental importance of physical, face-to-face social ties in the functioning of cities, these connectivity networks are not explicitly observed in their entirety. Attempts at estimating them often rely on unrealistic over-simplifications such as the assumption of spatial homogeneity. Here we propose a mathematical model of human interactions in terms of a local strategy of maximizing the number of beneficial connections attainable under the constraint of limited individual travelling-time budgets. By incorporating census and openly available online multi-modal transport data, we are able to characterize the connectivity of geometrically and topologically complex cities. Beyond providing a candidate measure of greatness, this model allows one to quantify and assess the impact of transport developments, population growth, and other infrastructure and demographic changes on a city. Supported by validations of gross domestic product and human immunodeficiency virus infection rates across US metropolitan areas, we illustrate the effect of changes in local and city-wide connectivities by considering the economic impact of two contemporary inter- and intra-city transport developments in the UK: High Speed 2 and London Crossrail. This derivation of the model suggests that the scaling of different urban indicators with population size has an explicitly mechanistic origin. PMID:26179988

  18. Evaluation of waste temperatures in AWF tanks for bypass mode operation of the 702-AZ ventilation system, Project W-030

    SciTech Connect

    Sathyanarayana, K.

    1997-09-10

    This report describes the results of thermal hydraulic analysis performed to provide data in support of Project W-030 to startup new 702-AZ Primary Ventilation System. During the startup of W-030 system, the ventilation system will be operating in bypass mode. In bypass made of operation, the system is capable of supplying 1000 cfm total flow for all four AWF doubleshell tanks. The design of the W-030 system is based on the assumption that both the recirculation loop of the primary ventilation system and the secondary ventilation which provides cooling would be operating. However, during the startup neither the recirculation system nor the secondary ventilation system will be operating. A minimum flow of 100 cfm is required to prevent any flammable gas associated risk. The remaining 600 cfm flow can be divided among the four tanks as necessary to keep the peak sludge temperatures below the operating temperature limit. For the purpose of determining the minimum flow required for cooling each tank, the thermal hydraulic analysis is performed to predict the peak sludge temperatures in AY/AZ tanks under different ventilation flows. The heat load for AZ farm tanks is taken from characterization reports and for the AY farm tanks, the heat load was estimated by thermal analysis using the measured waste temperatures and the waste liquid evaporation rates. The tank 241-AZ-101 and the tank 241-AZ-102 have heat loads of 241,600 and 199,500 Btu/hr respectively. The tank 241-AY-101 and tank 241-AY-102 have heat loads of 41,000 and 33,000 Btu/hr respectively. Using the ambient meteorological conditions of temperature and relative humidity for the air and tank, some soil surface and the sludge levels reported in recent documents, the peak sludge and supernatant temperatures were predicted for various primary ventilation flows ranging from 100 to 400 cfm for AZ tanks and 100 and 150 cfm for AY tanks. The results of these thermal hydraulic analyses are presented. Based on the

  19. Optimisation of city size.

    PubMed

    Laurila, Hannu

    2011-01-01

    Club theoretical analysis of migration between asymmetrical cities shows that centralised policy intervention is necessary to ensure the efficient allocation of people between cities. Administrative and economic measures are compared as policy instruments of central government. These instruments are found to differ in their effects on residential allocation and welfare. In particular, a lump-sum tax-transfer programme pools the welfare-creating potentials of cities, thus affecting the efficiency condition. Therefore, lump-sum tax-transfers are superior to both quantity rationing and Pigouvian taxes, and they also activate, rather than stabilise, migration. PMID:21584984

  20. City Lights of Europe

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Growth in 'mega-cities' is altering the landscape and the atmosphere in such a way as to curtail normal photosynthesis. By using data from The Defense Meteorological Satellite Program's Operational Linescan System, researchers have been able to look at urban sprawl by monitoring the emission of light from cities at night. By overlaying these 'light maps' onto other data such as soil and vegetation maps, the research shows that urbanization can have a variable but measurable impact on photosynthetic productivity. For more information, read Bright Lights, Big City Image by the NASA GSFC Scientific Visualization Studio

  1. The histone variant H2A.Z is dynamically expressed in the developing mouse placenta and in differentiating trophoblast stem cells.

    PubMed

    Kafer, Georgia R; Carlton, Peter M; Lehnert, Sigrid A

    2015-11-01

    The histone variant H2A.Z is important in establishing new chromatin environments necessary for permitting changes in gene expression and thus differentiation in mouse embryonic stem (mES) cells. In this study we show that H2A.Z is highly expressed in the early mouse placenta, and is specifically limited to progenitor-like trophoblast cells. Using in vitro models, we revealed distinct differences in H2A.Z abundance between undifferentiated, differentiating and differentiated mouse trophoblast stem (mTS) cells. Our work supports the hypothesis that in addition to roles in differentiating mES cells, H2A.Z is also involved in the differentiation of extra-embryonic tissues.

  2. H2A.Z depletion impairs proliferation and viability but not DNA double-strand breaks repair in human immortalized and tumoral cell lines

    PubMed Central

    Taty-Taty, Gemael-Cedrick; Courilleau, Celine; Quaranta, Muriel; Carayon, Alexandre; Chailleux, Catherine; Aymard, François; Trouche, Didier; Canitrot, Yvan

    2014-01-01

    In mammalian cells, DNA double-strand breaks (DSB) can be repaired by 2 main pathways, homologous recombination (HR) and non-homologous end joining (NHEJ). To give access to DNA damage to the repair machinery the chromatin structure needs to be relaxed, and chromatin modifications play major roles in the control of these processes. Among the chromatin modifications, changes in nucleosome composition can influence DNA damage response as observed with the H2A.Z histone variant in yeast. In mammals, p400, an ATPase of the SWI/SNF family able to incorporate H2A.Z in chromatin, was found to be important for histone ubiquitination and BRCA1 recruitment around DSB or for HR in cooperation with Rad51. Recent data with 293T cells showed that mammalian H2A.Z is recruited to DSBs and is important to control DNA resection, therefore participating both in HR and NHEJ. Here we show that depletion of H2A.Z in the osteosarcoma U2OS cell line and in immortalized human fibroblasts does not change parameters of DNA DSB repair while affecting clonogenic ability and cell cycle distribution. In addition, no recruitment of H2A.Z around DSB can be detected in U2OS cells either after local laser irradiation or by chromatin immunoprecipitation. These data suggest that the role of H2A.Z in DSB repair is not ubiquitous in mammals. In addition, given that important cellular parameters, such as cell viability and cell cycle distribution, are more sensitive to H2A.Z depletion than DNA repair, our results underline the difficulty to investigate the role of versatile factors such as H2A.Z. PMID:24240188

  3. The Sustainable City.

    ERIC Educational Resources Information Center

    Gangloff, Deborah

    1995-01-01

    Focuses on methods to make cities more sustainable through the processes of energy efficiency, pollution and waste reduction, capture of natural processes, and the merger of ecological, economic, and social factors. (LZ)

  4. City sewer collectors biocorrosion

    NASA Astrophysics Data System (ADS)

    Ksiażek, Mariusz

    2014-12-01

    This paper presents the biocorrosion of city sewer collectors impregnated with special polymer sulphur binders, polymerized sulphur, which is applied as the industrial waste material. The city sewer collectors are settled with a colony of soil bacteria which have corrosive effects on its structure. Chemoautotrophic nitrifying bacteria utilize the residues of halites (carbamide) which migrate in the city sewer collectors, due to the damaged dampproofing of the roadway and produce nitrogen salts. Chemoorganotrophic bacteria utilize the traces of organic substrates and produce a number of organic acids (formic, acetic, propionic, citric, oxalic and other). The activity of microorganisms so enables the origination of primary and secondary salts which affect physical properties of concretes in city sewer collectors unfavourably.

  5. Cincinnati; Our Convention City

    ERIC Educational Resources Information Center

    Borchin, Anna

    1970-01-01

    During Easter week, 1971, Cincinnati will be the hostess of the 50th anniversary convention of the Catholic Library Association. Items of historical interest concerning the city are briefly described. (NH)

  6. [Cities in peril, Mahgreb].

    PubMed

    Naciri, M

    1994-10-01

    The urban population has surpassed 50% in the Maghreb: first in Tunisia, followed by Algeria and Morocco. This phenomenon has greatly affected the distribution of power and the forms of its exercise in the political, social, and economic domain. The old city social strata are becoming extinct while city management is falling more and more under the control of cadres originally from rural areas. Urbanization is occurring at a slower pace than in other developing countries, however. In Morocco, the small- and medium-sized towns are growing at a faster rate than the cities. Their lack of infrastructure and services, like those that exist in the periphery of large cities, preoccupies the small- and medium-sized towns. The urban explosion is much more contained than its management is adapting. Legal and illegal housing will dominate the Moroccan city in the future. In the last decade, Moroccan authorities have tried to establish mechanisms to integrate populations in slums and illegal housing with the urban space. The Tunisians are also working on this. In Algeria, the rigid, urban formal management leaves no room to develop any type of housing. The problem of housing is even more grave here than the other 2 countries. Structural adjustment policies promote selling rather than renting houses. The government is not involved in social and health services. Algeria has a 2-tier society: a minority involved in the private sector and the majority who depends on the collapsing public sector which cannot meet the great needs of the poor. Persons with college degrees are unemployed in Algeria. One no longer knows how to build towns with the traditional medinas. The transportation system is falling apart in cities. Cities dump liquid and solid wastes directly into the sea or the wadis. The major risk of maghrebian cities lies in socioeconomic inequalities.

  7. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus.

    PubMed

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  8. AZ 242, a novel PPARalpha/gamma agonist with beneficial effects on insulin resistance and carbohydrate and lipid metabolism in ob/ob mice and obese Zucker rats.

    PubMed

    Ljung, Bengt; Bamberg, Krister; Dahllöf, Björn; Kjellstedt, Ann; Oakes, Nicholas D; Ostling, Jörgen; Svensson, Lennart; Camejo, Germán

    2002-11-01

    Abnormalities in fatty acid (FA) metabolism underlie the development of insulin resistance and alterations in glucose metabolism, features characteristic of the metabolic syndrome and type 2 diabetes that can result in an increased risk of cardiovascular disease. We present pharmacodynamic effects of AZ 242, a novel peroxisome proliferator activated receptor (PPAR)alpha/gamma agonist. AZ 242 dose-dependently reduced the hypertriglyceridemia, hyperinsulinemia, and hyperglycemia of ob/ob diabetic mice. Euglycemic hyperinsulinemic clamp studies showed that treatment with AZ 242 (1 micromol/kg/d) restored insulin sensitivity of obese Zucker rats and decreased insulin secretion. In vitro, in reporter gene assays, AZ 242 activated human PPARalpha and PPARgamma with EC(50) in the micro molar range. It also induced differentiation in 3T3-L1 cells, an established PPARgamma effect, and caused up-regulation of liver fatty acid binding protein in HepG-2 cells, a PPARalpha-mediated effect. PPARalpha-mediated effects of AZ 242 in vivo were documented by induction of hepatic cytochrome P 450-4A in mice. The results indicate that the dual PPARalpha/gamma agonism of AZ 242 reduces insulin resistance and has beneficial effects on FA and glucose metabolism. This effect profile could provide a suitable therapeutic approach to the treatment of type 2 diabetes, metabolic syndrome, and associated vascular risk factors. PMID:12401884

  9. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus

    PubMed Central

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  10. The Lysobacter capsici AZ78 Genome Has a Gene Pool Enabling it to Interact Successfully with Phytopathogenic Microorganisms and Environmental Factors.

    PubMed

    Puopolo, Gerardo; Tomada, Selena; Sonego, Paolo; Moretto, Marco; Engelen, Kristof; Perazzolli, Michele; Pertot, Ilaria

    2016-01-01

    Lysobacter capsici AZ78 has considerable potential for biocontrol of phytopathogenic microorganisms. However, lack of information about genetic cues regarding its biological characteristics may slow down its exploitation as a biofungicide. In order to obtain a comprehensive overview of genetic features, the L. capsici AZ78 genome was sequenced, annotated and compared with the phylogenetically related pathogens Stenotrophomonas malthophilia K729a and Xanthomonas campestris pv. campestris ATCC 33913. Whole genome comparison, supported by functional analysis, indicated that L. capsici AZ78 has a larger number of genes responsible for interaction with phytopathogens and environmental stress than S. malthophilia K729a and X. c. pv. campestris ATCC 33913. Genes involved in the production of antibiotics, lytic enzymes and siderophores were specific for L. capsici AZ78, as well as genes involved in resistance to antibiotics, environmental stressors, fungicides and heavy metals. The L. capsici AZ78 genome did not encompass genes involved in infection of humans and plants included in the S. malthophilia K729a and X. c. pv. campestris ATCC 33913 genomes, respectively. The L. capsici AZ78 genome provides a genetic framework for detailed analysis of other L. capsici members and the development of novel biofungicides based on this bacterial strain. PMID:26903975

  11. The Lysobacter capsici AZ78 Genome Has a Gene Pool Enabling it to Interact Successfully with Phytopathogenic Microorganisms and Environmental Factors

    PubMed Central

    Puopolo, Gerardo; Tomada, Selena; Sonego, Paolo; Moretto, Marco; Engelen, Kristof; Perazzolli, Michele; Pertot, Ilaria

    2016-01-01

    Lysobacter capsici AZ78 has considerable potential for biocontrol of phytopathogenic microorganisms. However, lack of information about genetic cues regarding its biological characteristics may slow down its exploitation as a biofungicide. In order to obtain a comprehensive overview of genetic features, the L. capsici AZ78 genome was sequenced, annotated and compared with the phylogenetically related pathogens Stenotrophomonas malthophilia K729a and Xanthomonas campestris pv. campestris ATCC 33913. Whole genome comparison, supported by functional analysis, indicated that L. capsici AZ78 has a larger number of genes responsible for interaction with phytopathogens and environmental stress than S. malthophilia K729a and X. c. pv. campestris ATCC 33913. Genes involved in the production of antibiotics, lytic enzymes and siderophores were specific for L. capsici AZ78, as well as genes involved in resistance to antibiotics, environmental stressors, fungicides and heavy metals. The L. capsici AZ78 genome did not encompass genes involved in infection of humans and plants included in the S. malthophilia K729a and X. c. pv. campestris ATCC 33913 genomes, respectively. The L. capsici AZ78 genome provides a genetic framework for detailed analysis of other L. capsici members and the development of novel biofungicides based on this bacterial strain. PMID:26903975

  12. Sinking coastal cities

    NASA Astrophysics Data System (ADS)

    Erkens, G.; Bucx, T.; Dam, R.; de Lange, G.; Lambert, J.

    2015-11-01

    In many coastal and delta cities land subsidence now exceeds absolute sea level rise up to a factor of ten. A major cause for severe land subsidence is excessive groundwater extraction related to rapid urbanization and population growth. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will sink below sea level. Land subsidence increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. In addition, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs for (infra)structure. The total damage worldwide is estimated at billions of dollars annually. As subsidence is often spatially variable and can be caused by multiple processes, an assessment of subsidence in delta cities needs to answer questions such as: what are the main causes? What is the current subsidence rate and what are future scenarios (and interaction with other major environmental issues)? Where are the vulnerable areas? What are the impacts and risks? How can adverse impacts be mitigated or compensated for? Who is involved and responsible to act? In this study a quick-assessment of subsidence is performed on the following mega-cities: Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok. Results of these case studies will be presented and compared, and a (generic) approach how to deal with subsidence in current and future subsidence-prone areas is provided.

  13. Microstructural Analysis of Severe Plastic Deformed Twin Roll Cast AZ31 for the Optimization of Superplastic Properties

    SciTech Connect

    Young, John P.; Askari, Hesam A.; Heiden, Michael J.; Hovanski, Yuri; Field, David P.; Zbib, Hussein M.

    2013-07-08

    In recent years magnesium alloys have attracted significant attention as potential candidates to replace many of the heavier metals used in some automotive applications. However, the limited formability of magnesium and its alloys at room temperature has driven interest in the superplastic forming magnesium as an alternative shaping method. Severe plastic deformation techniques have become a well studied method of refining the grain size and modifying the microstructural characteristics of many magnesium alloys to achieve greater superplastic properties. In this study twin roll cast (TRC) AZ31 magnesium alloy was subjected to equal channel angular pressing (ECAP) and friction stir welding (FSW). The influence of these severe plastic deformation processes on the grain size, texture and grain boundary character distribution was investigated to identify the optimum severe plastic deformation process for the superplastic forming of AZ31.

  14. Tensile properties of AZ11A-0 magnesium-alloy sheet under rapid-heating and constant temperature

    NASA Technical Reports Server (NTRS)

    Kurg, Ivo M

    1956-01-01

    Specimens of AZ31A-0 magnesium alloy sheet were heated to rupture at nominal rates of 0.2 F to 100 F per second under constant tensile load conditions. The data are presented and compared with the results of conventional tensile stress-strain tests at elevated temperatures after 1.2-hour exposure. A temperature-rate parameter was used to construct master curves from which stresses and temperatures for yield and rupture can be predicted under rapid-heating conditions. A comparison of the elevated-temperature tensile properties of AZ31A-0 and HK31XA-H24 magnesium-alloy sheet under both constant-temperature and rapid-heating conditions is included.

  15. Effects of heat input on the low power Nd:YAG pulse laser conduction weldability of magnesium alloy AZ61

    NASA Astrophysics Data System (ADS)

    Min, Dong; Shen, Jun; Lai, Shiqiang; Chen, Jie; Xu, Nan; Liu, Hui

    2011-01-01

    The effects of heat input on the low power Nd:YAG pulse laser conduction weldability of magnesium alloy AZ61 plates were investigated. The results show that for a hot-extruded AZ61 magnesium alloy plate laser conduction welding, the penetration depth and area of welds cross-section increased with an increase of the heat input. The microstructure of a band zone, which is located in the fusion zone (FZ) and close to the fusion boundary, evolved with an increase of the heat input. Moreover, an increase of the heat input increased the tendency of the formation of solidification cracking and liquation cracking. The porosities and average diameters of pores increased with an increase of the heat input but reduced sharply when a relatively large heat input was achieved. In addition, the degree of formation of craters increased linearly with an increase of the heat input.

  16. Study on the microstructural evolution of AZ31 magnesium alloy in a vertical twin-roll casting process

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Hu, Xiao-Dong; Han, Bing; Deng, Xiao-Hu; Ju, Dong-Ying

    2016-02-01

    Finite element method was employed to calculate the macroflow velocity and temperature distribution of the pool domain's biting zone in twin-roll casting. Macroanalysis results were inducted as boundary conditions into microanalysis. Phase field method (PFM) was adopted to investigate the microstructure evolution. Based on the Kim-Kim-Suzuki model, the effect of metal flow velocity was coupled on the solute gradient item, and the real physical parameters of AZ31 were inducted into the numerical calculation. We used the marker and cell method in the discrete element solution of microstructural pattern prediction of AZ31 magnesium alloys. The different flow velocity values that predicted the columnar dendrite evolution were discussed in detail. Numerical simulation results were also compared with the experiment analysis. The microstructure obtained by PFM agrees with the actual pattern observed via optical microscopy.

  17. Learning Cities on the Move

    ERIC Educational Resources Information Center

    Kearns, Peter

    2015-01-01

    The modern Learning City concept emerged from the work of OECD on lifelong learning with streams of Learning Cities and Educating Cities having much in common but having little contact with each other. While the early development of Learning Cities in the West has not been sustained, the present situation is marked by the dynamic development of…

  18. THE REDSHIFT AND NATURE OF AzTEC/COSMOS 1: A STARBURST GALAXY AT z = 4.6

    SciTech Connect

    Smolcic, V.; Capak, P.; Blain, A. W.; Salvato, M.; Masters, D.; Moric, I.; Riechers, D. A.; Ilbert, O.; Aretxaga, I.; Hughes, D.; Schinnerer, E.; Sheth, K.; Aravena, M.; Aussel, H.; Aguirre, J.; Berta, S.; Carilli, C. L.; Civano, F.; Fazio, G.; Huang, J.

    2011-04-20

    Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64{sup +0.06}{sub -0.08} for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 {mu}m), CSO/SHARC II (350 {mu}m), and CARMA and PdBI (3 mm). We do not detect CO(5 {yields} 4) line emission in the covered redshift ranges, 4.56-4.76 (PdBI/CARMA) and 4.94-5.02 (CARMA). If the line is within this bandwidth, this sets 3{sigma} upper limits on the gas mass to {approx}<8 x 10{sup 9} M{sub sun} and {approx}<5 x 10{sup 10} M{sub sun}, respectively (assuming similar conditions as observed in z {approx} 2 SMGs). This could be explained by a low CO-excitation in the source. Our analysis of the UV-IR spectral energy distribution of AzTEC 1 shows that it is an extremely young ({approx}<50 Myr), massive (M{sub *} {approx} 10{sup 11} M{sub sun}), but compact ({approx}<2 kpc) galaxy, forming stars at a rate of {approx}1300 M{sub sun} yr{sup -1}. Our results imply that AzTEC 1 is forming stars in a 'gravitationally bound' regime in which gravity prohibits the formation of a superwind, leading to matter accumulation within the galaxy and further generations of star formation.

  19. Chromosomal mapping of the human histone gene H2AZ to 4q24 by fluorescence in situ hybridization

    SciTech Connect

    Popescu, N.; Zimonjic, D.; Hatch, C.; Bonner, W. )

    1994-03-15

    The human gene locus H2AZ was assigned to chromosome 4 by challenging a panel of 27 human-hamster hybrid cell lines with oligonucleotide probes specific to two regions of the human gene. The human gene H2AZ locus has three EcoRI sites, yielding 2.9-kb upstream and 4.7-kb downstream fragments after digestion. Commercial Southern blots were obtained with EcoRI-digested DNA preparations from the 27 lines. An oligonucleotide probe, taagagaacgctagagggagctggtgttca, to intron 3 of the gene gave one human-specific band on these blots consistent in size with the expected 4.7-kb downstream EcoRI fragment; this band was mapped to chromosome 4 (2 hybrid lines with chromosome 4, 25 without it; 27 concordances, no discordances). A 5[prime] utr oligonucleotide probe, tgccttgcttgcttgagcttcagcggaatt, to the upstream 2.9-kb fragment yielded two bands on these Southern blots. The smaller band, consistent in size with the expected 2.9-kb EcoRI gene fragment, was also mapped to chromosome 4 (27 concordances, no discordances). The larger, approximately 6-kb band was mapped to chromosome 21 (7 hybrid lines with chromosome 21, 20 without it; 26 concordances, 1 discordance) and may result from a possible pseudogene. From these results, the human gene H2AZ is assigned to chromosome 4; a possible pseudogene is assigned to chromosome 21. Thus, the human gene H2AZ is not part of the clusters of human replication-lined histone genes that have been assigned to chromosome 1, 6 and 12.

  20. In vitro and in vivo studies of biodegradable fine grained AZ31 magnesium alloy produced by equal channel angular pressing.

    PubMed

    Ratna Sunil, B; Sampath Kumar, T S; Chakkingal, Uday; Nandakumar, V; Doble, Mukesh; Devi Prasad, V; Raghunath, M

    2016-02-01

    The objective of the present work is to investigate the role of different grain sizes produced by equal channel angular pressing (ECAP) on the degradation behavior of magnesium alloy using in vitro and in vivo studies. Commercially available AZ31 magnesium alloy was selected and processed by ECAP at 300°C for up to four passes using route Bc. Grain refinement from a starting size of 46μm to a grain size distribution of 1-5μm was successfully achieved after the 4th pass. Wettability of ECAPed samples assessed by contact angle measurements was found to increase due to the fine grain structure. In vitro degradation and bioactivity of the samples studied by immersing in super saturated simulated body fluid (SBF 5×) showed rapid mineralization within 24h due to the increased wettability in fine grained AZ31 Mg alloy. Corrosion behavior of the samples assessed by weight loss and electrochemical tests conducted in SBF 5× clearly showed the prominent role of enhanced mineral deposition on ECAPed AZ31 Mg in controlling the abnormal degradation. Cytotoxicity studies by MTT colorimetric assay showed that all the samples are viable. Additionally, cell adhesion was excellent for ECAPed samples particularly for the 3rd and 4th pass samples. In vivo experiments conducted using New Zealand White rabbits clearly showed lower degradation rate for ECAPed sample compared with annealed AZ31 Mg alloy and all the samples showed biocompatibility and no health abnormalities were noticed in the animals after 60days of in vivo studies. These results suggest that the grain size plays an important role in degradation management of magnesium alloys and ECAP technique can be adopted to achieve fine grain structures for developing degradable magnesium alloys for biomedical applications.

  1. 241-AZ-101 Mixer Pump Demonstration Test Gamma Cart Acceptance Test Procedure and Quality Test Plan (ATP and QTP)

    SciTech Connect

    WHITE, D.A.

    2000-03-01

    Shop Test of the Gamma Cart System to be used in the AZ-101 Mixer Pump Demonstration Test. Tests hardware and software. This procedure involves testing the Instrumentation involved with the Gamma Cart System, local and remote, including: depth indicators, speed controls, interface to data acquisition software and the raising and lowering functions. This Procedure will be performed twice, once for each Gamma Cart System. This procedure does not test the accuracy of the data acquisition software.

  2. 241-AZ-101 Mixer Pump Demonstration Test Gamma Cart Acceptance Test Procedure and Quality Test Plan (ATP and QTP)

    SciTech Connect

    WHITE, D.A.

    2000-01-27

    Shop test of the sludge mobilization cart system to be used in the AZ-101 Mixer Pump Demonstration Test Tests hardware and software. This procedure involves testing the Instrumentation involved with the Gamma Cart System, local and remote, including depth indicators, speed controls, interface to data acquisition software and the raising and lowering functions. This Procedure will be performed twice, once for each Gamma Cart System. This procedure does not test the accuracy of the data acquisition software.

  3. In vitro degradation, hemolysis, and cytocompatibility of PEO/PLLA composite coating on biodegradable AZ31 alloy.

    PubMed

    Wei, Zhongling; Tian, Peng; Liu, Xuanyong; Zhou, Bangxin

    2015-02-01

    Magnesium and its alloys have large potential as degradable and absorbable biomaterials because of their mechanical properties and biocompatibility. However, their corrosion resistance is usually inadequate especially in physiological environment, which limits their broad applications in biomedical areas. In this work, plasma electrolytic oxidized/poly(l-lactide) (PEO/PLLA) composite coating was successfully fabricated on biodegradable AZ31 alloy by combing PEO process and sealing with PLLA. The microstructure, elemental composition, and phase composition of the PEO/PLLA composite coating were investigated. The in vitro degradation of the PEO/PLLA composite coating in simulated body fluid (SBF) was also systematically evaluated. The results revealed that the PEO/PLLA composite coating improved the corrosion resistance of AZ31 alloy significantly. The corrosion potential shifted from -1.663V to more positive position -1.317 V and the corrosion current density was reduced with six-order of magnitude. The Mg(2+) ions, hydrogen release, and pH value change of solution caused by degradation were all decreased significantly. Moreover, the PEO process played a critical role in sustaining the integrity of the implant in long-term service. The result of hemolysis test showed that the PEO/PLLA composite coating vested AZ31 alloy a low hemolysis ratio (0.806 ± 0.771)%, which is much lower than the safe value of 5% according to ISO 10993-4. For the cytocompatibility test, compared with bare AZ31 alloy and PEO coating, MC3T3-E1 cells showed much better adhesion and proliferation on the PEO/PLLA composite coating with nearly 4-fold increase of cells after 7-day cultivation, indicating that the PEO/PLLA composite coating has good biocompatibility for biomedical applications.

  4. Effect of hot working on the damping capacity and mechanical properties of AZ31 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Lee, K.; Kang, C.; Kim, K.

    2015-04-01

    Magnesium alloys have received much attention for their lightweight and other excellent properties, such as low density, high specific strength, and good castability, for use in several industrial and commercial applications. However, both magnesium and its alloys show limited room-temperature formability owing to the limited number of slip systems associated with their hexagonal close-packed crystal structure. It is well known that crystallographic texture plays an important role in both plastic deformation and macroscopic anisotropy of magnesium alloys. Many authors have concentrated on improving the room- temperature formability of Mg alloys. However, despite having a lot of excellent properties in magnesium alloy, the study for various properties of magnesium alloy have not been clarified enough yet. Mg alloys are known to have a good damping capacity compared to other known metals and their alloys. Also, the damping properties of metals are generally recognized to be dependent on microstructural factors such as grain size and texture. However, there are very few studies on the relationship between the damping capacity and texture of Magnesium alloys. Therefore, in this study, specimens of the AZ31 magnesium alloy, were processed by hot working, and their texture and damping property investigated. A 60 mm × 60 mm × 40 mm rectangular plate was cut out by machining an ingot of AZ31 magnesium alloy (Mg-3Al-1Zn in mass%), and rolling was carried out at 673 K to a rolling reduction of 30%. Then, heat treatment was carried out at temperatures in the range of 573-723 K for durations in the range of 30-180 min. The samples were immediately quenched in oil after heat treatment to prevent any change in the microstructure. Texture was evaluated on the compression planes by the Schulz reflection method using nickel-filtered Cu Kα radiation. Electron backscatter diffraction measurements were conducted to observe the spatial distribution of various orientations. Specimens

  5. Sinking Coastal Cities

    NASA Astrophysics Data System (ADS)

    Erkens, G.; Stuurman, R.; De Lange, G.; Bucx, T.; Lambert, J.

    2014-12-01

    In many coastal cities land subsidence now exceeds absolute sea level rise up to a factor of ten. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will continue to sink, even below sea level. The ever increasing industrial and domestic demand for water in these cities results in excessive groundwater extraction, causing severe subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick sequences of soft soil. The impacts of subsidence are further exacerbated by climate-induced sea level rise. Land subsidence results in two types damage: foremost it increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. Secondly, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs of roads and transportation networks, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually. To survey the extent of groundwater associated subsidence, we conducted a quick-assessment of subsidence in a series of mega-cities (Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok). For each city research questions included: what are the main causes, how much is the current subsidence rate and what are predictions, where are the vulnerable areas, what are the impacts and risks, how can adverse impacts can be mitigated or compensated for, and what governmental bodies are involved and responsible to act? Using the assessment, this paper discusses subsidence modelling and measurement results from the selected cities. The focus is on the importance of delayed settlement after increases in hydraulic heads, the role of the subsurface composition for subsidence rates and best practice solutions for subsiding cities. For the latter, urban (ground)water management, adaptive flood risk management

  6. Laser surface forming of AlCoCrCuFeNi particle reinforced AZ91D matrix composites

    NASA Astrophysics Data System (ADS)

    Meng, Guanghui; Yue, T. M.; Lin, Xin; Yang, Haiou; Xie, Hui; Ding, Xu

    2015-07-01

    Traditionally, the laser melt injection (LMI) technique can only be used for forming ceramic particles reinforced metal matrix composites (MMCs) for enhancing surface properties of lightweight engineering materials. In this research, the LMI method was employed to form metal particles reinforced MMCs on AZ91D instead. This was viable because of the unique properties of the AlCoCrCuFeNi high-entropy alloy (HEA) metal particles used. The large difference in melting point between the HEA and the substrate material (AZ91D), and the limited reaction and the lack of fusion between the HEA and Mg have made it possible that a metal particles reinforced AZ91D composite material was produced. The reason of limited reaction was considered mainly due to the relatively high mixing enthalpy between the HEA constituent elements and Mg. Although there was some melting occurred at the particles surface with some solute segregation found in the vicinity close to the surface, intermetallic compounds were not observed. With regard to the wear resistance of the MMCs, it was found that when the volume fraction of the reinforcement phase, i.e. the HEA particles, reached about 0.4, the wear volume loss of the coating was only one-seventh of that of the substrate material.

  7. Influence of Tension-Compression Asymmetry on the Mechanical Behavior of AZ31B Magnesium Alloy Sheets in Bending

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Beeh, Elmar; Friedrich, Horst E.

    2016-03-01

    Magnesium alloys are promising materials for lightweight design in the automotive industry due to their high strength-to-mass ratio. This study aims to study the influence of tension-compression asymmetry on the radius of curvature and energy absorption capacity of AZ31B-O magnesium alloy sheets in bending. The mechanical properties were characterized using tension, compression, and three-point bending tests. The material exhibits significant tension-compression asymmetry in terms of strength and strain hardening rate due to extension twinning in compression. The compressive yield strength is much lower than the tensile yield strength, while the strain hardening rate is much higher in compression. Furthermore, the tension-compression asymmetry in terms of r value (Lankford value) was also observed. The r value in tension is much higher than that in compression. The bending results indicate that the AZ31B-O sheet can outperform steel and aluminum sheets in terms of specific energy absorption in bending mainly due to its low density. In addition, the AZ31B-O sheet was deformed with a larger radius of curvature than the steel and aluminum sheets, which brings a benefit to energy absorption capacity. Finally, finite element simulation for three-point bending was performed using LS-DYNA and the results confirmed that the larger radius of curvature of a magnesium specimen is mainly attributed to the high strain hardening rate in compression.

  8. Influence of shot peening on corrosion properties of biocompatible magnesium alloy AZ31 coated by dicalcium phosphate dihydrate (DCPD).

    PubMed

    Mhaede, Mansour; Pastorek, Filip; Hadzima, Branislav

    2014-06-01

    Magnesium alloys are promising materials for biomedical applications because of many outstanding properties like biodegradation, bioactivity and their specific density and Young's modulus are closer to bone than the commonly used metallic implant materials. Unfortunately their fatigue properties and low corrosion resistance negatively influenced their application possibilities in the field of biomedicine. These problems could be diminished through appropriate surface treatments. This study evaluates the influence of a surface pre-treatment by shot peening and shot peening+coating on the corrosion properties of magnesium alloy AZ31. The dicalcium phosphate dihydrate coating (DCPD) was electrochemically deposited in a solution containing 0.1M Ca(NO3)2, 0.06M NH4H2PO4 and 10mL/L of H2O2. The effect of shot peening on the surface properties of magnesium alloy was evaluated by microhardness and surface roughness measurements. The influence of the shot peening and dicalcium phosphate dihydrate layer on the electrochemical characteristics of AZ31 magnesium alloy was evaluated by potentiodynamic measurements and electrochemical impedance spectroscopy in 0.9% NaCl solution at a temperature of 22±1°C. The obtained results were analyzed by the Tafel-extrapolation method and equivalent circuit method. The results showed that the application of shot peening process followed by DCPD coating improves the properties of the AZ31 surface from corrosion and mechanical point of view. PMID:24863232

  9. Effect of cw-CO2 laser surface treatment on structure and properties of AZ91 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Iwaszko, Józef; Strzelecka, Monika

    2016-06-01

    In the study, samples of AZ91 magnesium alloy were subjected to a surface remelting treatment by means of a continuous wave (cw) CO2 laser. The scope of the investigation included both macro- and microstructural examination, hardness measurements, and wear resistance tests. The investigation has shown that remelting treatment leads to a strong refinement of structure in the surface layer and a more even distribution of phases. Fine α-phase dendrites have been observed to dominate in the remelting zone. The dendritic arm spacing in the laser treated surface was in the range of 1-2.5 μm. The structural changes triggered by remelting have contributed to an increase in the hardness and the wear resistance of AZ91 alloy. The microhardness of the remelted zone has increased to 71-93 HV0.05 for single-strip remelting and to 84-107 HV0.05 for multi-strip remelting in comparison with about ~60 HV0.05 for untreated alloy. The friction coefficient has decreased from 0.375 for material w/o treatment to 0.311 for remelted material. SEM investigations of samples after tribological tests have revealed the presence of parallel grooves proving the occurrence of microploughing and micro cutting of the material during the tribological testing. The results of the conducted investigation have indicated a beneficial influence of the cw-CO2 laser remelting treatment on the structure and properties of AZ91 alloy.

  10. Early Science with the Large Millimeter Telescope: CO and [C II] Emission in the z = 4.3 AzTEC J095942.9+022938 (COSMOS AzTEC-1)

    NASA Astrophysics Data System (ADS)

    Yun, Min S.; Aretxaga, I.; Gurwell, M. A.; Hughes, D. H.; Montaña, A.; Narayanan, G.; Rosa-González, D.; Sánchez-Argüelles, D.; Schloerb, F. P.; Snell, R. L.; Vega, O.; Wilson, G. W.; Zeballos, M.; Chavez, M.; Cybulski, R.; Díaz-Santos, T.; De La Luz, V.; Erickson, N.; Ferrusca, D.; Gim, H. B.; Heyer, M. H.; Iono, D.; Pope, A.; Rogstad, S. M.; Scott, K. S.; Souccar, K.; Terlevich, E.; Terlevich, R.; Wilner, D.; Zavala, J. A.

    2015-12-01

    Measuring redshifted CO line emission is an unambiguous method for obtaining an accurate redshift and total cold gas content of optically faint, dusty starburst systems. Here, we report the first successful spectroscopic redshift determination of AzTEC J095942.9+022938 (`COSMOS AzTEC-1'), the brightest 1.1 mm continuum source found in the AzTEC/James Clerk Maxwell Telescope survey (Scott et al.), through a clear detection of the redshifted CO (4-3) and CO (5-4) lines using the Redshift Search Receiver on the Large Millimeter Telescope. The CO redshift of z = 4.3420 ± 0.0004 is confirmed by the detection of the redshifted 158 μm [C II] line using the Submillimeter Array. The new redshift and Herschel photometry yield LFIR = (1.1 ± 0.1) × 1013 L⊙ and SFR ≈ 1300 M⊙ yr-1. Its molecular gas mass derived using the ultraluminous infrared galaxy conversion factor is 1.4 ± 0.2 × 1011M⊙ while the total interstellar medium mass derived from the 1.1 mm dust continuum is 3.7 ± 0.7 × 1011M⊙ assuming Td = 35 K. Our dynamical mass analysis suggests that the compact gas disc (r ≈ 1.1 kpc, inferred from dust continuum and spectral energy distribution analysis) has to be nearly face-on, providing a natural explanation for the uncommonly bright, compact stellar light seen by the HST. The [C II] line luminosity L_[C II]= 7.8± 1.1 × 10^9 L_{⊙} is remarkably high, but it is only 0.04 per cent of the total IR luminosity. AzTEC COSMOS-1 and other high redshift sources with a spatially resolved size extend the tight trend seen between [C II]/FIR ratio and ΣFIR among IR-bright galaxies reported by Díaz-Santos et al. by more than an order of magnitude, supporting the explanation that the higher intensity of the IR radiation field is responsible for the `[C II] deficiency' seen among luminous starburst galaxies.

  11. Characterizing Sky Brightness Variations 2014: Fort Collins, CO and Tucson, AZ

    NASA Astrophysics Data System (ADS)

    Culver, Roger B.; Craine, Erin M.; Wall, Renae E.

    2015-05-01

    Internet enabled sky brightness meters (iSBM), designed and manufactured by STEM Laboratory, Inc., have been operated and tested at several locations for the last few years. The iSBM units are zenith looking, single channel, broadband photometers that record sky brightness continuously at a cadence of about 40-sec. They operate every night regardless of weather, thus providing a record of sky brightness useful not only for astronomers (clear nights), but also wildlife biologists who are concerned with the real range of local sky brightness. Data logged include time, date, geographic location, elevation, sky brightness, twilight times, moonrise/set times, lunar phase, cloud cover, temperature, humidity, barometric pressure, and dew-point. We have examined recent archives of iSBM data for two different types of locations: Fort Collins, CO and Tucson, AZ. From the archives we have calculated statistics of sky brightness and compare the results to provide a qualitative and quantitative description of natural ranges of sky brightness trends.

  12. New Az/El mount for Haystack Observatory's Small Radio Telescope kit

    NASA Astrophysics Data System (ADS)

    Cobb, M. L.

    2005-12-01

    The Small Radio Telescope (SRT) kit was designed by Haystack Observatory as part of their educational outreach effort. The SRT uses a custom designed FFT based radio spectrometer receiver with a controller to position a 2.3m dish to make various radio astronomy observations including the 21 cm spin flip line of atomic hydrogen. Because there is no sizable commercial market for a two dimensional mount for dishes of this size, finding an appropriate provider as been a recurring problem for the project. Originally, the kit used a modified motor mount from Kaultronics called the H180. Two of these motors were combined by a specially designed adaptor to allow motion in azimuth and elevation. When Kaultronics was bought out by California Amplifier they discontinued production of the H180. The next iteration used a compact unit called the alfa-spid which was made in Germany and imported through Canada. The alfa-spid was designed to point various ham radio antennas and proved problematic with 2.3m dishes. Most recently the CASSI (Custom Astronomical Support Services, Inc.) corporation has designed and certified a robust Az/El mount capable of supporting dishes up to 12 feet (3.6m) with 100 MPH wind loads. This paper presents the design and operating characteristics of the new CASSI mount. The CASSI mount is now shipped with the SRT kit and should serve the project well for the foreseeable future.

  13. Achieving Superplasticity in AZ31 Magnesium Alloy Processed by Hot Extrusion and Rolling

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Wu, Mengling; Ma, Wenliang; Lu, Yi; Yuan, Shuai

    2016-01-01

    Experiments were conducted on ultrafine-grained AZ31 magnesium alloy sheet which was prepared through nano-grained powders processed by hot extrusion at 300 °C plus hot-rolling for four passes at 200. The superplastic behavior had been evaluated in a low-temperature range of 423-523 K and strain rates varied from 5 × 10-4 to 5 × 10-3 s-1. The experiment results showed that tensile testing revealed the superplastic elongations with a maximum measured elongation of 227% when tested at 523 K and strain rate of 5 × 10-4 s-1. The superplastic deformation behavior was attributed to the ultrafine-grained microstructures. The measured elongations mainly depended upon the initial strain rate and temperature, and the strain rate sensitivity m was ~0.5 for this condition. The results indicated that powder metallurgy and subsequent hot extrusion plus rolling were promising approaches to produce the ultrafine-grained magnesium alloy sheet with superplasticity.

  14. High current pulsed electron beam treatment of AZ31 Mg alloy

    SciTech Connect

    Gao Bo; Hao Shengzhi; Zou Jianxin; Grosdidier, Thierry; Jiang Limin; Zhou Jiyang; Dong Chuang

    2005-11-15

    This paper reports, for the first time, an analysis of the effect of High Current Pulsed Electron Beam (HCPEB) on a Mg alloy. The AZ31 alloy was HCPEB treated in order to see the potential of this fairly recent technique in modifying its wear resistance. For the 2.5 J/cm{sup 2} beam energy density used in the present work, the evaporation mode was operative and led to the formation of a ''wavy'' surface and the absence of eruptive microcraters. The selective evaporation of Mg over Al led to an Al-rich melted surface layer and precipitation hardening from the over saturated solid solution. Due to the increase in hardness of the top surface layer, the friction coefficient values were lowered by more than 20% after the HCPEB treatments, and the wear resistance was drastically (by a factor of 6) improved. The microhardness of the HCPEB samples was also increased significantly down to a depth of about 500 {mu}m, far exceeding the heat-affected zone (about 40 {mu}m). This is due to the effect of the propagation of the shockwave associated with this HCPEB treatment.

  15. Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites.

    PubMed

    Zhang, Lingkun; Cai, Weiwei; Chen, Wu-Ya; Zhang, Li; Hu, Kaikai; Guan, Yan-Qing

    2016-03-30

    The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection.

  16. Texture enhancement during grain growth of magnesium alloy AZ31B

    SciTech Connect

    Bhattacharyya, Jishnu J.; Agnew, S. R.; Muralidharan, G.

    2015-01-03

    In this paper, the microstructure and texture evolution during annealing of rolled Mg alloy AZ31B, at temperatures ranging from 260 to 450°C, is characterized, and a grain growth exponent of n=5, indicating inhibition of grain growth, is observed. Broadening of the normalized grain size distributions, which indicates abnormal grain growth, was observed at all temperatures investigated. It is shown, using a Zener-type analysis for pinning of grain boundaries by particles, that impurity-based particles are responsible for grain growth inhibition and abnormal grain growth. The strong basal texture which develops during rolling of the Mg alloy, resulting in an initial peak intensity in the (0002) pole figure of nine multiples of a random distribution (MRD), increases to ~15 MRD during annealing at 400 and 450°C. Furthermore, a specific texture component {0001}(1120) is observed in the orientation distribution, which increases from 10 to 23 MRD at 400°C. It is hypothesized that the anisotropic grain boundary properties (i.e. low angle boundaries have low energy and mobility) are responsible for the texture strengthening. Additionally, electron backscattered diffraction reveals the recrystallized microstructure to contain a significant number of boundaries with ~30° misorientation about the <0001> direction, and this boundary type persists throughout most annealing treatments explored.

  17. Tailoring degradation of AZ31 alloy by surface pre-treatment and electrospun PCL fibrous coating.

    PubMed

    Hanas, T; Sampath Kumar, T S; Perumal, Govindaraj; Doble, Mukesh

    2016-08-01

    AZ31 magnesium alloy was coated with polycaprolactone (PCL) nano-fibrous layer using electrospinning technique so as to control degradation in physiological environment. Before coating, the alloy was treated with HNO3 to have good adhesion between the coating and substrate. To elucidate the role of pre-treatment and coating, samples only with PCL coating as well as HNO3 treatment only were prepared for comparison. Best coating adhesion of 4B grade by ASTM D3359-09 tape test was observed for pre-treated samples. The effect of coating on in vitro degradation and biomineralization was studied using supersaturated simulated body fluid (SBF 5×). The weight loss and corrosion results obtained by immersion test showed that the combination of HNO3 pre-treatment and PCL coating is very effective in controlling the degradation rate and improving bioactivity. Cytotoxicity studies using L6 cells showed that PCL coated sample has better cell adhesion and proliferation compared to uncoated samples. Nano-fibrous PCL coating combined with prior acid treatment seems to be a promising method to tailor degradation rate with enhanced bioactivity of Mg alloys. PMID:27157726

  18. Study on Pressurized Solidification Behavior and Microstructure Characteristics of Squeeze Casting Magnesium Alloy AZ91D

    NASA Astrophysics Data System (ADS)

    Han, Zhiqiang; Pan, Haowei; Li, Yanda; Luo, Alan A.; Sachdev, Anil K.

    2015-02-01

    Squeeze casting technology for magnesium alloys has a great application potential in automobile manufacturing and has received increasing attention from both academic and industrial communities. In this study, the pressurized solidification behavior of magnesium alloy AZ91D in squeeze casting process was investigated using computer-aided cooling curve analysis (CA-CCA). It was found that the applied pressure increased both the start and end temperatures of primary α-Mg formation but had little effect on the sizes of temperature ranges. Moreover, the applied pressure increased the start temperature and decreased the end temperature of eutectic reaction during the solidification, resulting in a larger temperature range of eutectic reaction compared with solidification under atmospheric pressure. The grains were remarkably refined, and the eutectic fraction increased with increasing applied pressure. The dendritic microstructure with a larger secondary dendrite arm spacing (SDAS) was observed under a higher applied pressure at the central part of the experimental casting. By correlating the CA-CCA and SDAS data, it was found that SDAS and the cooling rate at the maximum α-Mg growth could be fit into the power law equation in classic solidification theories.

  19. Deformation Behavior of AZ80 Wrought Magnesium Alloy at Cryogenic Temperatures

    SciTech Connect

    Tang Wei; Li Xiuyan; Han Enhou; Xu Yongbo; Li Yiyi

    2006-03-31

    The influence of temperature on the deformation and failure behavior of AZ80 wrought Mg alloy has been examined from 77K to 298K. It is found that the yield strength (YS) and ultimate strength (UTS) are increasing with the temperature decreasing, while the elongation is decreasing especial between 213K and 143K. Based on the mechanical tests, observation of environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM), it is proposed that the alloy deforms mainly by slips and twins, but undergoes different mechanism of cleavage in the range of testing temperature. At T>213K, the alloy ductility is higher because the dislocations could pass through twins but pile up at precipitate phase: Mg17Al12, which causes the crack nucleate. At T<143K, the alloy ductility is lower because the dislocation slip are suppressed greatly and dislocations pile up at twins, and cause crack nucleate and expand along twins quickly. At 143K

  20. THE AzTEC/SMA INTERFEROMETRIC IMAGING SURVEY OF SUBMILLIMETER-SELECTED HIGH-REDSHIFT GALAXIES

    SciTech Connect

    Younger, Joshua D.; Fazio, Giovanni G.; Huang Jiasheng; Ashby, Matthew L. N.; Gurwell, Mark A.; Petitpas, Glen R.; Wilner, David J.; Yun, Min S.; Wilson, Grant W.; Scott, Kimberly S.; Austermann, Jason; Perera, Thushara; Peck, Alison B.; Hughes, David H.; Aretxaga, Itziar; Kim, Sungeun; Lowenthal, James D.

    2009-10-10

    We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size approx2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology-including the nature of SMGs with multiple radio counterparts and constraints on the physical scale of the far infrared-of the sample, and (3) find additional evidence for a population of extremely luminous, radio-dim SMGs that peaks at higher redshift than previous, radio-selected samples. In particular, the presence of such a population of high-redshift sources has important consequences for models of galaxy formation-which struggle to account for such objects even under liberal assumptions-and dust production models given the limited time since the big bang.

  1. A study of strontium doped calcium phosphate coatings on AZ31.

    PubMed

    Singh, Satish S; Roy, Abhijit; Lee, Boeun E; Ohodnicki, John; Loghmanian, Autrine; Banerjee, Ipsita; Kumta, Prashant N

    2014-07-01

    Calcium phosphate (CaP) coatings have been studied to tailor the uncontrolled non-uniform corrosion of Mg based alloys while simultaneously enhancing bioactivity. The use of immersion techniques to deposit CaP coatings is attractive due to the ability of the approach to coat complex structures. In the current study, AZ31 substrates were subjected to various pretreatment conditions prior to depositing Sr(2+) doped and undoped CaP coatings. It was hypothesized that the bioactivity and corrosion protection of CaP coatings could be improved by doping with Sr(2+). Heat treatment to elevated temperatures resulted in the diffusion of alloying elements, Mg and Zn, into the pretreated layer. Sr(2+) doped and undoped CaP coatings formed on the pretreated substrates consisted of biphasic mixtures of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA). Electrochemical corrosion experiments indicated that the extent of Sr(2+) doping and pretreatment both influenced the corrosion protection. Cytotoxicity was evaluated with MC3T3-E1 mouse preosteoblasts and human mesenchymal stem cells (hMSCs). For both cell types, proliferation decreased upon increasing the Sr(2+) concentration. However, both osteogenic gene and protein expression significantly increased upon increasing Sr(2+) concentration. These results suggest that Sr(2+) doped coatings are capable of promoting osteogenic differentiation on degradable Mg alloys, while also enhancing corrosion protection, in comparison to undoped CaP coatings. PMID:24857503

  2. The cold-rolling behaviour of AZ31 tubes for fabrication of biodegradable stents.

    PubMed

    Zhang, Yaowu; Kent, Damon; Wang, Gui; StJohn, David; Dargusch, Matthew S

    2014-11-01

    Mg alloys are receiving considerable attention for biomedical stents due to their combination of good mechanical properties and high biodegradability. Cold rolling is necessary to process Mg alloy tubes before final drawing and fabrication of the magnesium stents. In this paper, cold-rolled tubes were subjected to a cross-sectional reduction rate (ε) of up to 19.7%, and were further processed at various ratios of wall-thickness to diameter reduction (Q) from 0 to 2.24 with a constant ε of 19.7%. The results show that the cold-rolled tubes exhibited a rise in ultimate tensile strength (UTS), yield strength (YS), and a reduction in elongation as ε increased from 5.5% to 19.7%. UTS, YS and elongation decreased when Q was increased from 0 to 2.24. Mechanical twinning was observed and analysed. Extension twins increased with increasing ε and were almost saturated at a ε of 16.5%. Extension twins play an important role in determining the evolution of mechanical behaviour in the case of increasing ε, whilst contraction/double twins and secondary extension twins have a large effect on mechanical behaviour in the case of varying Q. The results indicate that the proportions and types of twins play a major role in determining the mechanical behaviour of the AZ31 tubes.

  3. Influence of chemical liquids on the fatigue crack growth of the AZ31 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Wang, Zhang-Zhong; He, Xian-Cong; Bai, Yun-Qiang; Ba, Zhi-Xin; Dai, Yu-Ming; Zhou, Heng-Zhi

    2012-03-01

    The fatigue crack growth behavior of an AZ31 magnesium alloy was investigated by comparing the effect of zirconate and phosphate chemical liquids. The morphology, components, and phase compositions of the chemical depositions at the fatigue crack tip were analyzed by employing scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. For samples with and without the chemical liquids, their stress-intensity factor values at the fatigue crack tip were compared by using a stress-strain gauge. The results demonstrated that a zirconate film (Zr x O y ·Zn x O y ) and a phosphate film (Zn3(PO4)2·4H2O and MgZnP2O7) could be formed on the fatigue crack-surface at the fatigue crack tip. The stress distribution was changed because of the chemical depositions and the causticity of the chemical liquids. This could decrease the stress-intensity factor value and thus effectively cause fatigue crack closure, which reduces the fatigue crack growth rate. Moreover, it was found that the fatigue crack closure effect of zirconates was more positive than that of phosphates.

  4. Lap Fillet Welding of Thin Sheet AZ31 Magnesium Alloy with Pulsed Nd:YAG Laser

    NASA Astrophysics Data System (ADS)

    Ishak, Mahadzir; Yamasaki, Kazuhiko; Maekawa, Katsuhiro

    In recent years, reducing the size and weight of consumer products requires the joining of thin sheets of magnesium alloys with both thickness and joining area of less than 1mm, especially for packaging purposes. Conventional welding processes are difficult to joint a thin sheet magnesium alloy because of high heat input, which in turns leads to various problems such as burn through and cracks. In this study, lap fillet welding of thin sheet magnesium alloy AZ31B with a thickness of 0.3 mm has been carried out using a pulsed Nd:YAG laser beam. The influences of gap, laser beam center location and scan speed on joint appearances have been investigated. It was found that defects were significantly reduced when the gap width was less than 35 µm when the laser beam center was located just on the edge of the upper specimen (x=0), and scan speed was varied from 400 to 450 m/min. Wider bond width at average value of 300 µm was achieved when the beam center was at x=0 with a wide range of scan speeds from 250 to 450 mm/min compared with the cases at x=-0.1 and -0.2 mm from edge. Increases in bond width and minimal defects at x=0 improve fracture load by 68% compared with those at x=-0.1 mm.

  5. Corrosion of Mg alloy AZ91D in the presence of living cells.

    PubMed

    Seuss, F; Seuss, S; Turhan, M C; Fabry, B; Virtanen, S

    2011-11-01

    Mg and Mg alloys are of interest for biodegradable implants as they readily corrode in biological fluids, and dissolved Mg ions are nontoxic. Even though it is well known that Mg dissolution leads to pH increase in the surroundings, the effect of the corrosion-induced alkalization on the biological environment has not been studied in detail. We therefore explored the interactions between corrosion-induced pH increase and cell growth on Mg alloy AZ91D surface. Cell adhesion and spreading on the alloy surface is unimpeded initially. However, with time a large fraction of cells de-adhere. We attribute this to the observed increase of the pH in the cell culture medium in the process of alloy dissolution. Cytotoxicity tests with HeLa cells grown on glass surfaces confirm that cell death increases with increasing alkalinity of the cell culture medium. We also show that a the cells that adhere on the Mg alloy surface act as a corrosion-blocking surface layer. In consequence, a slower pH increase in the medium takes place when the alloy surface is covered with cells. Electrochemical impedance spectroscopy measurements (EIS) verify that a cell layer slows down the corrosion process.

  6. Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites.

    PubMed

    Zhang, Lingkun; Cai, Weiwei; Chen, Wu-Ya; Zhang, Li; Hu, Kaikai; Guan, Yan-Qing

    2016-03-30

    The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection. PMID:26794946

  7. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    SciTech Connect

    Mackie, D.; Robson, J.D.; Withers, P.J.; Turski, M.

    2015-06-15

    Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al{sub 8}Mn{sub 5} in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets.

  8. Failure analysis of AZ31 magnesium alloy sheets based on the extended GTN damage model

    NASA Astrophysics Data System (ADS)

    Wang, Rui-ze; Chen, Zhang-hua; Li, Yu-jie; Dong, Chao-fang

    2013-12-01

    Based on the Gurson-Tvergaard-Needleman (GTN) model and Hill's quadratic anisotropic yield criterion, a combined experimental-numerical study on fracture initiation in the process of thermal stamping of Mg alloy AZ31 sheets was carried out. The aim is to predict the formability of thermal stamping of the Mg alloy sheets at different temperatures. The presented theoretical framework was implemented into a VUMAT subroutine for ABAQUS/EXPLICIT. Internal damage evolution due to void growth and coalescence developed at different temperatures in the Mg alloy sheets was observed by scanning electron microscopy (SEM). Moreover, the thermal effects on the void growth, coalescence, and fracture behavior of the Mg alloy sheets were analyzed by the extended GTN model and forming limit diagrams (FLD). Parameters employed in the GTN model were determined from tensile tests and numerical iterative computation. The distribution of major and minor principal strains in the specimens was determined from the numerical results. Therefore, the corresponding forming limit diagrams at different stress levels and temperatures were drawn. The comparison between the predicted forming limits and the experimental data shows a good agreement.

  9. Increased corrosion resistance of the AZ80 magnesium alloy by rapid solidification.

    PubMed

    Aghion, E; Jan, L; Meshi, L; Goldman, J

    2015-11-01

    Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the β-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons.

  10. Deformation Behavior of AZ80 Wrought Magnesium Alloy at Cryogenic Temperatures

    NASA Astrophysics Data System (ADS)

    Tang, Wei; Li, Xiuyan; Han, Enhou; Xu, Yongbo; Li, Yiyi

    2006-03-01

    The influence of temperature on the deformation and failure behavior of AZ80 wrought Mg alloy has been examined from 77K to 298K. It is found that the yield strength (YS) and ultimate strength (UTS) are increasing with the temperature decreasing, while the elongation is decreasing especial between 213K and 143K. Based on the mechanical tests, observation of environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM), it is proposed that the alloy deforms mainly by slips and twins, but undergoes different mechanism of cleavage in the range of testing temperature. At T>213K, the alloy ductility is higher because the dislocations could pass through twins but pile up at precipitate phase: Mg17Al12, which causes the crack nucleate. At T<143K, the alloy ductility is lower because the dislocation slip are suppressed greatly and dislocations pile up at twins, and cause crack nucleate and expand along twins quickly. At 143K

  11. Effects of CH3OH Addition on Plasma Electrolytic Oxidation of AZ31 Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    He, Yongyi; Chen, Li; Yan, Zongcheng; Zhang, Yalei

    2015-09-01

    Plasma electrolytic oxidation (PEO) films on AZ31 magnesium alloys were prepared in alkaline silicate electrolytes (base electrolyte) with the addition of different volume concentrations of CH3OH, which was used to adjust the thickness of the vapor sheath. The compositions, morphologies, and thicknesses of ceramic layers formed with different CH3OH concentrations were determined via X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Corrosion behavior of the oxide films was evaluated in 3.5 wt.% NaCl solution using potentiodynamic polarization tests. PEO coatings mainly comprised Mg, MgO, and Mg2SiO4. The addition of CH3OH in base electrolytes affected the thickness, pores diameter, and Mg2SiO4 content in the films. The films formed in the electrolyte containing 12% CH3OH exhibited the highest thickness. The coatings formed in the electrolyte containing different concentrations of CH3OH exhibited similar corrosion resistance. The energy consumption of PEO markedly decreased upon the addition of CH3OH to the electrolytes. The result is helpful for energy saving in the PEO process. supported by National Natural Science Foundation of China (No. 21376088), the Project of Production, Education and Research, Guangdong Province and Ministry of Education (Nos. 2012B09100063, 2012A090300015), and Guangzhou Science and Technology Plan Projects of China (No. 2014Y2-00042)

  12. Texture enhancement during grain growth of magnesium alloy AZ31B

    DOE PAGES

    Bhattacharyya, Jishnu J.; Agnew, S. R.; Muralidharan, G.

    2015-01-03

    In this paper, the microstructure and texture evolution during annealing of rolled Mg alloy AZ31B, at temperatures ranging from 260 to 450°C, is characterized, and a grain growth exponent of n=5, indicating inhibition of grain growth, is observed. Broadening of the normalized grain size distributions, which indicates abnormal grain growth, was observed at all temperatures investigated. It is shown, using a Zener-type analysis for pinning of grain boundaries by particles, that impurity-based particles are responsible for grain growth inhibition and abnormal grain growth. The strong basal texture which develops during rolling of the Mg alloy, resulting in an initial peakmore » intensity in the (0002) pole figure of nine multiples of a random distribution (MRD), increases to ~15 MRD during annealing at 400 and 450°C. Furthermore, a specific texture component {0001}(1120) is observed in the orientation distribution, which increases from 10 to 23 MRD at 400°C. It is hypothesized that the anisotropic grain boundary properties (i.e. low angle boundaries have low energy and mobility) are responsible for the texture strengthening. Additionally, electron backscattered diffraction reveals the recrystallized microstructure to contain a significant number of boundaries with ~30° misorientation about the <0001> direction, and this boundary type persists throughout most annealing treatments explored.« less

  13. Mussel-inspired functionalization of PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy.

    PubMed

    Tian, Peng; Xu, Demin; Liu, Xuanyong

    2016-05-01

    The rapid degradation of magnesium-based implants in physiological environments in vivo not only will quickly deteriorate their mechanical strengths but will also lead to a severe change of the micro-environment around the implants, which may cause the final failure of magnesium-based implants. In this work, a polycaprolactone (PCL) layer was prepared to seal the plasma electrolytic oxidization coating (PEO) to form a PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy, followed by further surface functionalization with polydopamine. The in vitro degradation behaviors of the bare AZ31 alloy and coated samples were evaluated in a simulated body fluid (SBF) using the potentiodynamic polarization curve test and the static immersion test. The bioactivity of the samples was investigated using the SBF soaking test. The cytocompatibility of all samples was evaluated using the cytotoxicity test and analysis of the adhesion and proliferation of osteoblast cells (MC3T3-E1) directly cultivated on the sample surface. The results showed that the PCL layer successfully sealed the pores of the PEO coating, and then the polydopamine layer formed on its surface. The in vitro degradation tests showed that the PEO/PCL composite coating improved the corrosion resistance of the AZ31 alloy in SBF with a more positive corrosion potential and a lower corrosion current density. Due to the protection of the PEO/PCL composite coating, the surrounding environment showed nearly no influence on the degradation of the coated sample, which led to no obvious local alkalization and hydrogen evolution. Moreover, compared with the AZ31 alloy and PEO coating, the PEO/PCL composite coating was more suitable for cell adhesion and proliferation. After further surface functionalization by polydopamine, the corrosion resistance of the composite coating was maintained, while its bioactivity was significantly enhanced with a large amount of hydroxyapatite (HA) formed on its surface after

  14. Transient Liquid Phase Diffusion Bonding of Magnesium Alloy (Mg-AZ31) to Titanium Alloy (Ti-6Al-4V)

    NASA Astrophysics Data System (ADS)

    Atieh, Anas Mahmoud

    The magnesium alloy Mg-AZ31 and titanium alloy Ti-6Al-4V have physical characteristics and mechanical properties that makes it attractive for a wide range of engineering applications in the aerospace and automotive industries. However, the differences in melting temperature and coefficient of thermal expansion hinder the use of traditional fusion welding techniques. Transient liquid phase (TLP) bonding of magnesium alloy Mg-AZ31 and titanium alloy Ti-6Al- 4V was performed and different interlayer types and configurations were used to facilitate joint formation. The joining of these alloys using Ni foils was successful at a bonding temperature of 515°C, bonding pressure 0.2 MPa, for bonding time of 5 minutes. At the Ni/Mg-AZ31 bond interface, the formation of a eutectic liquid between Mg and Ni was observed. The formation of Mg2Ni and Mg3AlNi2 were identified along the bond interface resulting in an isothermally solidified joint. At the Ni/Ti-6Al-4V interface, the solid-state diffusion process results in joint formation. The use of double Ni-Cu sandwich joint resulted in further enhancement in joint formation and this produced joints with greater shear strength values. The configuration of Mg-AZ31/Cu- Ni/Ti-6Al-4V or Mg-AZ31/Ni-Cu/Ti-6Al-4V influence the mechanism of bonding and the type of intermetallics formed within the joint. The application of thin Ni electrodeposited coatings resulted in further enhancements of joint quality due to better surface-to-surface contact and a reduction in the formation of intermetallics at the joint. The effect of Cu nano-particles in the coatings was found to decrease the eutectic zone width and this resulted in an increase the shear strength of the joints. The highest shear strength of 69 MPa was possible with bonds made using coatings containing Cu nano-particle dispersion.

  15. Mussel-inspired functionalization of PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy.

    PubMed

    Tian, Peng; Xu, Demin; Liu, Xuanyong

    2016-05-01

    The rapid degradation of magnesium-based implants in physiological environments in vivo not only will quickly deteriorate their mechanical strengths but will also lead to a severe change of the micro-environment around the implants, which may cause the final failure of magnesium-based implants. In this work, a polycaprolactone (PCL) layer was prepared to seal the plasma electrolytic oxidization coating (PEO) to form a PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy, followed by further surface functionalization with polydopamine. The in vitro degradation behaviors of the bare AZ31 alloy and coated samples were evaluated in a simulated body fluid (SBF) using the potentiodynamic polarization curve test and the static immersion test. The bioactivity of the samples was investigated using the SBF soaking test. The cytocompatibility of all samples was evaluated using the cytotoxicity test and analysis of the adhesion and proliferation of osteoblast cells (MC3T3-E1) directly cultivated on the sample surface. The results showed that the PCL layer successfully sealed the pores of the PEO coating, and then the polydopamine layer formed on its surface. The in vitro degradation tests showed that the PEO/PCL composite coating improved the corrosion resistance of the AZ31 alloy in SBF with a more positive corrosion potential and a lower corrosion current density. Due to the protection of the PEO/PCL composite coating, the surrounding environment showed nearly no influence on the degradation of the coated sample, which led to no obvious local alkalization and hydrogen evolution. Moreover, compared with the AZ31 alloy and PEO coating, the PEO/PCL composite coating was more suitable for cell adhesion and proliferation. After further surface functionalization by polydopamine, the corrosion resistance of the composite coating was maintained, while its bioactivity was significantly enhanced with a large amount of hydroxyapatite (HA) formed on its surface after

  16. Universities scale like cities.

    PubMed

    van Raan, Anthony F J

    2013-01-01

    Recent studies of urban scaling show that important socioeconomic city characteristics such as wealth and innovation capacity exhibit a nonlinear, particularly a power law scaling with population size. These nonlinear effects are common to all cities, with similar power law exponents. These findings mean that the larger the city, the more disproportionally they are places of wealth and innovation. Local properties of cities cause a deviation from the expected behavior as predicted by the power law scaling. In this paper we demonstrate that universities show a similar behavior as cities in the distribution of the 'gross university income' in terms of total number of citations over 'size' in terms of total number of publications. Moreover, the power law exponents for university scaling are comparable to those for urban scaling. We find that deviations from the expected behavior can indeed be explained by specific local properties of universities, particularly the field-specific composition of a university, and its quality in terms of field-normalized citation impact. By studying both the set of the 500 largest universities worldwide and a specific subset of these 500 universities--the top-100 European universities--we are also able to distinguish between properties of universities with as well as without selection of one specific local property, the quality of a university in terms of its average field-normalized citation impact. It also reveals an interesting observation concerning the working of a crucial property in networked systems, preferential attachment.

  17. Earth's City Lights

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Earth's city lights was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earth's surface. The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. (Compare western Europe with China and India.) Cities tend to grow along coastlines and transportation networks. Even without the underlying map, the outlines of many continents would still be visible. The United States interstate highway system appears as a lattice connecting the brighter dots of city centers. In Russia, the Trans-Siberian railroad is a thin line stretching from Moscow through the center of Asia to Vladivostok. The Nile River, from the Aswan Dam to the Mediterranean Sea, is another bright thread through an otherwise dark region. Even more than 100 years after the invention of the electric light, some regions remain thinly populated and unlit. Antarctica is entirely dark. The interior jungles of Africa and South America are mostly dark, but lights are beginning to appear there. Deserts in Africa, Arabia, Australia, Mongolia, and the United States are poorly lit as well (except along the coast), along with the boreal forests of Canada and Russia, and the great mountains of the Himalaya. The Earth Observatory article Bright Lights, Big City describes how NASA scientists use city light data to map urbanization. Image by Craig Mayhew and Robert Simmon, NASA GSFC, based on DMSP data

  18. Ultrafine particles in cities.

    PubMed

    Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

    2014-05-01

    Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. PMID:24503484

  19. Finding the Lost City

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Nicholas Clapp, a filmmaker and archeology enthusiast, had accumulated extensive information concerning Ubar, the fabled lost city of ancient Arabia. When he was unable to identify its exact location, however, he turned to the Jet Propulsion Laboratory (JPL) for assistance in applying orbital remote sensing techniques. JPL scientists searched NASA's shuttle imaging radar, as well as Landsat and SPOT images and discovered ancient caravan tracks. This enabled them to prepare a map of the trails, which converged at a place known as Ash Shisr. An expedition was formed, which found structures and artifacts from a city that predates previous area civilization by a thousand years. Although it will take time to validate the city as Ubar, the discovery is a monumental archeological triumph.

  20. Ultrafine particles in cities.

    PubMed

    Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

    2014-05-01

    Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts.

  1. Building functional cities.

    PubMed

    Henderson, J Vernon; Venables, Anthony J; Regan, Tanner; Samsonov, Ilia

    2016-05-20

    The literature views many African cities as dysfunctional with a hodgepodge of land uses and poor "connectivity." One driver of inefficient land uses is construction decisions for highly durable buildings made under weak institutions. In a novel approach, we model the dynamics of urban land use with both formal and slum dwellings and ongoing urban redevelopment to higher building heights in the formal sector as a city grows. We analyze the evolution of Nairobi using a unique high-spatial resolution data set. The analysis suggests insufficient building volume through most of the city and large slum areas with low housing volumes near the center, where corrupted institutions deter conversion to formal sector usage. PMID:27199420

  2. Reproducing in cities.

    PubMed

    Mace, Ruth

    2008-02-01

    Reproducing in cities has always been costly, leading to lower fertility (that is, lower birth rates) in urban than in rural areas. Historically, although cities provided job opportunities, initially residents incurred the penalty of higher infant mortality, but as mortality rates fell at the end of the 19th century, European birth rates began to plummet. Fertility decline in Africa only started recently and has been dramatic in some cities. Here it is argued that both historical and evolutionary demographers are interpreting fertility declines across the globe in terms of the relative costs of child rearing, which increase to allow children to outcompete their peers. Now largely free from the fear of early death, postindustrial societies may create an environment that generates runaway parental investment, which will continue to drive fertility ever lower.

  3. Expression of Non-acetylatable H2A.Z in Myoblast Cells Blocks Myoblast Differentiation through Disruption of MyoD Expression.

    PubMed

    Law, Cindy; Cheung, Peter

    2015-05-22

    H2A.Z is a histone H2A variant that is essential for viability in Tetrahymena and Drosophila and also during embryonic development of mice. Although implicated in diverse cellular processes, including transcriptional regulation, chromosome segregation, and heterochromatin formation, its essential function in cells remains unknown. Cellular differentiation is part of the developmental process of multicellular organisms. To elucidate the roles of H2A.Z and H2A.Z acetylation in cellular differentiation, we examined the effects of expressing wild type (WT) or a non-acetylatable form of H2A.Z in the growth and differentiation of the myoblast C2C12 cell line. Ectopic expression of wild type or mutant H2A.Z resulted in distinct phenotypes in the differentiation of the C2C12 cells and the formation of myotubes. Most strikingly, expression of the H2A.Z non-acetylatable mutant (H2A.Z-Ac-mut) resulted in a complete block of myoblast differentiation. We determined that this phenotype is caused by a loss of MyoD expression in the Ac-mut-expressing cells prior to and after induction of differentiation. Moreover, chromatin accessibility assays showed that the promoter region of MyoD is less accessible in the differentiation-defective cells. Altogether, these new findings show that expression of the Ac-mut form of H2A.Z resulted in a dominant phenotype that blocked differentiation due to chromatin changes at the MyoD promoter.

  4. Expression of Non-acetylatable H2A.Z in Myoblast Cells Blocks Myoblast Differentiation through Disruption of MyoD Expression*

    PubMed Central

    Law, Cindy; Cheung, Peter

    2015-01-01

    H2A.Z is a histone H2A variant that is essential for viability in Tetrahymena and Drosophila and also during embryonic development of mice. Although implicated in diverse cellular processes, including transcriptional regulation, chromosome segregation, and heterochromatin formation, its essential function in cells remains unknown. Cellular differentiation is part of the developmental process of multicellular organisms. To elucidate the roles of H2A.Z and H2A.Z acetylation in cellular differentiation, we examined the effects of expressing wild type (WT) or a non-acetylatable form of H2A.Z in the growth and differentiation of the myoblast C2C12 cell line. Ectopic expression of wild type or mutant H2A.Z resulted in distinct phenotypes in the differentiation of the C2C12 cells and the formation of myotubes. Most strikingly, expression of the H2A.Z non-acetylatable mutant (H2A.Z-Ac-mut) resulted in a complete block of myoblast differentiation. We determined that this phenotype is caused by a loss of MyoD expression in the Ac-mut-expressing cells prior to and after induction of differentiation. Moreover, chromatin accessibility assays showed that the promoter region of MyoD is less accessible in the differentiation-defective cells. Altogether, these new findings show that expression of the Ac-mut form of H2A.Z resulted in a dominant phenotype that blocked differentiation due to chromatin changes at the MyoD promoter. PMID:25839232

  5. Inner City Asthma

    PubMed Central

    Togias, Alkis

    2014-01-01

    SYNOPSIS The inner city has long been recognized as an area of high asthma morbidity and mortality. A wide range of factors interact to create this environment. These factors include well-recognized asthma risk factors that are not specific to the inner city, the structure and delivery of health care, the location and function of the urban environment, and social inequities. This article will review these facets and discuss successful and unsuccessful interventions in order to understand what is needed to solve this problem. PMID:25459579

  6. The Plains City Story

    ERIC Educational Resources Information Center

    van Olphen, Marcela; Rios, Francisco; Berube, William; Dexter, Robin; McCarthy, Robert

    2006-01-01

    This case study portrays a contemporary phenomenon that affects many U.S. school districts. Specifically, the authors address the challenges that the superintendent of the Plains City school district faced as a result of a change in the demographic distribution of his district. The gradual development of the pig farming industry in Plains City…

  7. Clean Cities Tools

    SciTech Connect

    2014-12-19

    The U.S. Department of Energy's Clean Cities offers a large collection of Web-based tools on the Alternative Fuels Data Center. These calculators, interactive maps, and data searches can assist fleets, fuels providers, and other transportation decision makers in their efforts to reduce petroleum use.

  8. Making Cities Green.

    ERIC Educational Resources Information Center

    Goldstein, Neil B.; Engel, Jane

    1981-01-01

    Describes several examples of urban parks and the renewal of city open spaces. Community groups interested in getting funding from government or private sources must cope with budget restrictions by making effective, innovative use of available money. Government agencies with funds allocated for urban improvements are mentioned. (AM)

  9. Big-City Rules

    ERIC Educational Resources Information Center

    Gordon, Dan

    2011-01-01

    When it comes to implementing innovative classroom technology programs, urban school districts face significant challenges stemming from their big-city status. These range from large bureaucracies, to scalability, to how to meet the needs of a more diverse group of students. Because of their size, urban districts tend to have greater distance…

  10. Mexico City aerosol study

    SciTech Connect

    Falcon, Y.I. ); Ramirez, C.R. )

    1988-01-01

    Mexico City is located in a valley at high elevation (2,268 m) and is subject to atmospheric inversion related problems similar to those found in Denver, Colorado. In addition, Mexico City has a tropical climate (latitude 19{degrees} 25 minutes N), and therefore has more sunlight available for production of photochemical smog. There are approximately 9.5 million people spread in a 1,500 km{sup 2} (25 sq. mi) urban area, and more than two million automobiles (D.G.P.T. 1979) which use leaded gasoline. Furthermore, Mexico City is the principal industrial center in the country with more than 131,000 industries. The growth of the city has led to a serious air pollution problem, and there is concern over the possible pollutant effects on human health. The authors discuss work done to characterize the chemical composition of the aerosol. It is shown that many of the organic compounds which have been detected in urban aerosols are carcinogens.

  11. Accepted into Education City

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    Qatar's Education City, perhaps the world's most diverse campus, is almost entirely unknown in the United States, but represents the next step in the globalization of American higher education--international franchising. Aided by technology such as online libraries, distance learning and streaming video, U.S. universities offer--and charge tuition…

  12. India's Cities in Crisis.

    ERIC Educational Resources Information Center

    Bryjak, George J.

    1984-01-01

    Indian cities are growing rapidly due to natural increase and migration from rural areas. This has caused huge pollution problems and has resulted in overcrowded schools and hospitals. Conflict between religious groups has increased; so has crime. India is modernizing, but not fast enough. (CS)

  13. CITIES ARE CHANGING.

    ERIC Educational Resources Information Center

    RAVITZ, MEL

    THE EFFECT OF PHYSICAL AND SOCIAL CHANGES IN LARGE CITIES ARE DISCUSSED. POPULATION GROWTH IN THE LAST FEW YEARS HAS OCCURRED PRIMARILY IN THE SUBURBS. URBAN RENEWAL HAS REALIGNED AND RELOCATED THE RACES AND THE SOCIAL CLASSES, AND FREEWAY CONSTRUCTION HAS CREATED INTERURBAN STRIPS. CASUALTIES OF THESE CHANGES ARE CROWDING THE MIDDLE NEIGHBORHOODS…

  14. Nature in the City.

    ERIC Educational Resources Information Center

    Ferbert, Mary Lou

    1981-01-01

    Describes a science program developed by the Cleveland Museum of Natural History, "Nature in the City," in which students and teachers learn together about the natural community surrounding their school. Includes program's rationale, list of "adventures," and methods. Discusses strategies of Sherlock Holmes'"adventure" focusing on animal tracks…

  15. Bug City: Bees [Videotape].

    ERIC Educational Resources Information Center

    1998

    "Bug City" is a video series created to help children learn about insects and other small critters. All aspects of bug life are touched upon including body structure, food, habitat, life cycle, mating habits, camouflage, mutualism (symbiosis), adaptations, social behavior, and more. Each program features dramatic microscopic photography, fun…

  16. New City, New Challenges

    ERIC Educational Resources Information Center

    Matthews, Frank

    2010-01-01

    After eight years at the helm of the City College of New York, where Dr. Gregory Williams grew enrollment at the minority-serving institution by 60 percent, instituted more rigorous admissions standards and launched the college's first capital campaign that raised more than $300 million, last fall he became the 27th president of the University of…

  17. City Kids Go Green.

    ERIC Educational Resources Information Center

    Taylor, Tricia

    1993-01-01

    Describes Outward Bound Urban Resources Initiative, a six-week summer course whose goal is to work with urban youth to develop solutions for local environmental problems. Among the activities described include converting city lots into parks, neighborhood cleanup, and tree planting. (MDH)

  18. Bug City: Ants [Videotape].

    ERIC Educational Resources Information Center

    1998

    "Bug City" is a video series created to help children (grades 1-6) learn about insects and other small critters. All aspects of bug life are touched upon including body structure, food, habitat, life cycle, mating habits, camouflage, mutualism (symbiosis), adaptations, social behavior, and more. Each program features dramatic microscopic…

  19. Bug City: Beetles [Videotape].

    ERIC Educational Resources Information Center

    1998

    "Bug City" is a video series created to help children learn about insects and other small critters. All aspects of bug life are touched upon including body structure, food, habitat, life cycle, mating habits, camouflage, mutualism (symbiosis), adaptations, social behavior, and more. Each program features dramatic microscopic photography, fun…

  20. The New City Commons

    ERIC Educational Resources Information Center

    Crossland, Janice

    1975-01-01

    Cities throughout the country are sponsoring family projects that convert vacant lots and rooftops to productive neighborhood gardens. It is hoped that utilization of these otherwide wasted areas will provide extra food for low income families, as well as promote community spirit and organization. (MA)

  1. The Schizosaccharomyces pombe JmjC-Protein, Msc1, Prevents H2A.Z Localization in Centromeric and Subtelomeric Chromatin Domains

    PubMed Central

    Buchanan, Luke; Durand-Dubief, Mickaël; Roguev, Assen; Sakalar, Cagri; Wilhelm, Brian; Strålfors, Annelie; Shevchenko, Anna; Aasland, Rein; Shevchenko, Andrej; Ekwall, Karl; Francis Stewart, A.

    2009-01-01

    Eukaryotic genomes are repetitively packaged into chromatin by nucleosomes, however they are regulated by the differences between nucleosomes, which establish various chromatin states. Local chromatin cues direct the inheritance and propagation of chromatin status via self-reinforcing epigenetic mechanisms. Replication-independent histone exchange could potentially perturb chromatin status if histone exchange chaperones, such as Swr1C, loaded histone variants into wrong sites. Here we show that in Schizosaccharomyces pombe, like Saccharomyces cerevisiae, Swr1C is required for loading H2A.Z into specific sites, including the promoters of lowly expressed genes. However S. pombe Swr1C has an extra subunit, Msc1, which is a JumonjiC-domain protein of the Lid/Jarid1 family. Deletion of Msc1 did not disrupt the S. pombe Swr1C or its ability to bind and load H2A.Z into euchromatin, however H2A.Z was ectopically found in the inner centromere and in subtelomeric chromatin. Normally this subtelomeric region not only lacks H2A.Z but also shows uniformly lower levels of H3K4me2, H4K5, and K12 acetylation than euchromatin and disproportionately contains the most lowly expressed genes during vegetative growth, including many meiotic-specific genes. Genes within and adjacent to subtelomeric chromatin become overexpressed in the absence of either Msc1, Swr1, or paradoxically H2A.Z itself. We also show that H2A.Z is N-terminally acetylated before, and lysine acetylated after, loading into chromatin and that it physically associates with the Nap1 histone chaperone. However, we find a negative correlation between the genomic distributions of H2A.Z and Nap1/Hrp1/Hrp3, suggesting that the Nap1 chaperones remove H2A.Z from chromatin. These data describe H2A.Z action in S. pombe and identify a new mode of chromatin surveillance and maintenance based on negative regulation of histone variant misincorporation. PMID:19911051

  2. Sinking coastal cities

    NASA Astrophysics Data System (ADS)

    Erkens, Gilles; Bucx, Tom; Dam, Rien; De Lange, Ger; Lambert, John

    2014-05-01

    In many coastal and delta cities land subsidence now exceeds absolute sea level rise up to a factor of ten. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will sink below sea level. Land subsidence increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. In addition, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs. This effects roads and transportation networks, hydraulic infrastructure - such as river embankments, sluice gates, flood barriers and pumping stations -, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually. Excessive groundwater extraction after rapid urbanization and population growth is the main cause of severe land subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick sequences of soft soil. Because of ongoing urbanization and population growth in delta areas, in particular in coastal megacities, there is, and will be, more economic development in subsidence-prone areas. The impacts of subsidence are further exacerbated by extreme weather events (short term) and rising sea levels (long term).Consequently, detrimental impacts will increase in the near future, making it necessary to address subsidence related problems now. Subsidence is an issue that involves many policy fields, complex technical aspects and governance embedment. There is a need for an integrated approach in order to manage subsidence and to develop appropriate strategies and measures that are effective and efficient on both the short and long term. Urban (ground)water management, adaptive flood risk management and related spatial planning strategies are just examples of the options available. A major rethink is needed to deal with the 'hidden' but urgent

  3. [Itinerant physicians, the art of healing and doctors in national history (Mexico City, 1877-1911)].

    PubMed

    Agostoni, Claudia

    2008-01-01

    The uncertainty and mistrust towards the presence and activities of academic medical practitioners in Mexico City during the Porfirio Díaz government (1877-1911) convinced these professionals that is was essential to create, strengthen and transmit a respectable, competent and homogeneous image of the profession. To this purpose they recovered, recreated and adapted the ethical maxims of the occidental medical culture to their professional work, and rescued eminent medical figures of Mexico's convulse nineteenth century from being lost in the oblivion of history. Their goal - as it will be expounded in the following pages - was to respond, oppose and neutralize the criticism and disbelief expressed by the public against their professional performance.

  4. Monitoring Lysobacter capsici AZ78 using strain specific qPCR reveals the importance of the formulation for its survival in vineyards.

    PubMed

    Segarra, Guillem; Puopolo, Gerardo; Porcel-Rodríguez, Elena; Giovannini, Oscar; Pertot, Ilaria

    2016-02-01

    Survival in the phyllosphere is a critical feature for biofungicides based on non-spore forming bacteria. Moreover, knowledge of their persistence on plants is important to design effective formulations and application techniques. With this scope, the aim of this work was to develop a specific method to monitor the fate in the environment of Lysobacter capsici AZ78, a biocontrol agent of Plasmopara viticola, and to evaluate the contribution of formulation in its persistence on grapevine leaves. A strain-specific primer pair derived from REP-PCR fingerprinting was used in quantitative PCR experiments to track the evolution of L. capsici AZ78 population in vineyards. The population reached between 5 and 6 log10 cells gram of leaf(-1) after application and decreased by more than 100 times in one week. Multiple regression analysis showed that unfavourable temperature was the main environmental factor correlating with the decrease of L. capsici AZ78 persistence on grapevine leaves. Importantly, the use of formulation additives protected L. capsici AZ78 against environmental factors and improved its persistence on the leaves by more than 10 times compared to nude cells. Formulation and the knowledge about the persistence of L. capsici AZ78 in vineyards will be useful to develop commercial biofungicides for foliar application. PMID:26691736

  5. The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken.

    PubMed

    Bruce, Kimberley; Myers, Fiona A; Mantouvalou, Evangelia; Lefevre, Pascal; Greaves, Ian; Bonifer, Constanze; Tremethick, David J; Thorne, Alan W; Crane-Robinson, Colyn

    2005-01-01

    The replacement histone H2A.Z is variously reported as being linked to gene expression and preventing the spread of heterochromatin in yeast, or concentrated at heterochromatin in mammals. To resolve this apparent dichotomy, affinity-purified antibodies against the N-terminal region of H2A.Z, in both a triacetylated and non-acetylated state, are used in native chromatin immmuno-precipitation experiments with mononucleosomes from three chicken cell types. The hyperacetylated species concentrates at the 5' end of active genes, both tissue specific and housekeeping but is absent from inactive genes, while the unacetylated form is absent from both active and inactive genes. A concentration of H2A.Z is also found at insulators under circumstances implying a link to barrier activity but not to enhancer blocking. Although acetylated H2A.Z is widespread throughout the interphase genome, at mitosis its acetylation is erased, the unmodified form remaining. Thus, although H2A.Z may operate as an epigenetic marker for active genes, its N-terminal acetylation does not. PMID:16204459

  6. Monitoring Lysobacter capsici AZ78 using strain specific qPCR reveals the importance of the formulation for its survival in vineyards.

    PubMed

    Segarra, Guillem; Puopolo, Gerardo; Porcel-Rodríguez, Elena; Giovannini, Oscar; Pertot, Ilaria

    2016-02-01

    Survival in the phyllosphere is a critical feature for biofungicides based on non-spore forming bacteria. Moreover, knowledge of their persistence on plants is important to design effective formulations and application techniques. With this scope, the aim of this work was to develop a specific method to monitor the fate in the environment of Lysobacter capsici AZ78, a biocontrol agent of Plasmopara viticola, and to evaluate the contribution of formulation in its persistence on grapevine leaves. A strain-specific primer pair derived from REP-PCR fingerprinting was used in quantitative PCR experiments to track the evolution of L. capsici AZ78 population in vineyards. The population reached between 5 and 6 log10 cells gram of leaf(-1) after application and decreased by more than 100 times in one week. Multiple regression analysis showed that unfavourable temperature was the main environmental factor correlating with the decrease of L. capsici AZ78 persistence on grapevine leaves. Importantly, the use of formulation additives protected L. capsici AZ78 against environmental factors and improved its persistence on the leaves by more than 10 times compared to nude cells. Formulation and the knowledge about the persistence of L. capsici AZ78 in vineyards will be useful to develop commercial biofungicides for foliar application.

  7. Plastic Deformation Characteristics Of AZ31 Magnesium Alloy Sheets At Elevated Temperature

    SciTech Connect

    Park, Jingee; Lee, Jongshin; You, Bongsun; Choi, Seogou; Kim, Youngsuk

    2007-05-17

    Using lightweight materials is the emerging need in order to reduce the vehicle's energy consumption and pollutant emissions. Being a lightweight material, magnesium alloys are increasingly employed in the fabrication of automotive and electronic parts. Presently, magnesium alloys used in automotive and electronic parts are mainly processed by die casting. The die casting technology allows the manufacturing of parts with complex geometry. However, the mechanical properties of these parts often do not meet the requirements concerning the mechanical properties (e.g. endurance strength and ductility). A promising alternative can be forming process. The parts manufactured by forming could have fine-grained structure without porosity and improved mechanical properties such as endurance strength and ductility. Because magnesium alloy has low formability resulted form its small slip system at room temperature it is usually formed at elevated temperature. Due to a rapid increase of usage of magnesium sheets in automotive and electronic industry it is necessary to assure database for sheet metal formability and plastic yielding properties in order to optimize its usage. Especially, plastic yielding criterion is a critical property to predict plastic deformation of sheet metal parts in optimizing process using CAE simulation. Von-Mises yield criterion generally well predicts plastic deformation of steel sheets and Hill'1979 yield criterion predicts plastic deformation of aluminum sheets. In this study, using biaxial tensile test machine yield loci of AZ31 magnesium alloy sheet were obtained at elevated temperature. The yield loci ensured experimentally were compared with the theoretical predictions based on the Von-Mises, Hill, Logan-Hosford, and Barlat model.

  8. Mechanical Behavior and Microstructural Analysis of Extruded AZ31B Magnesium Alloy Processed by Backward Extrusion

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Beeh, Elmar; Friedrich, Horst E.; Grünheid, Thomas

    2016-07-01

    This study investigates the mechanical behavior of an extruded AZ31B magnesium alloy profile at various strain rates from 0.001 to 375/s. The electron backscatter diffraction analysis revealed that the profile has \\{ { 0 0 0 1} \\}< 1 0overline{1} 0 rangle and \\{ {1 0overline{1} 0 }\\}< { 1 1overline{2} 0}rangle textures. Due to the textures, the profile exhibits pronounced anisotropy in mechanical properties. In the extrusion direction (ED), the profile shows the highest yield strength (YS) but the lowest total elongation at fracture (TE) due to a hard activation of non-basal slip and \\{ { 1 0overline{1} 1} \\}< { 1 0overline{1} overline{2} } rangle twinning; in the diagonal direction (DD), it shows the lowest ultimate tensile strength (UTS) but the highest TE due to an easy activation of basal slip; in the transverse direction (TD), it shows the lowest YS due to an easy activation of \\{ {10overline{1} 2} \\}< {10overline{1} overline{1} } rangle twinning. Moreover, the number of twins increases with the increasing strain rate. This indicates that deformation twinning becomes prevalent to accommodate high-rate deformation. Due to the different deformation mechanisms, the profile exhibits an orientation-dependent effect of strain rate on the mechanical properties. A positive effect of strain rate on the YS and UTS was found in the ED, while the effect of strain rate on the YS is negligible in the DD and TD. The TE in the ED, DD, and TD decreases in general as the strain rate increases. Fractographic analysis under a scanning electron microscope revealed that the fracture is a mixed mode of ductile and brittle fracture, and the magnesium oxide inclusions could be the origins of the fracture.

  9. 76 FR 30907 - Proposed Foreign-Trade Zone-Eloy, AZ; Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... Railroad line opposite Sasco Road, Red Rock. The sites are owned by the City of Eloy (Site 1), Walton International Group (USA), Inc. and Walton Arizona, LLC (Site 2), Walton International Group (USA), Inc. (Site 3) and Walton International Group (USA), Inc and Walton Arizona, LLC (Site 4). The application...

  10. New York City's Education Battles

    ERIC Educational Resources Information Center

    Meyer, Peter

    2008-01-01

    When Bloomberg gave his first State of the City address, in January, 2002, he announced his intention to seek mayoral control of the schools and abolish the infamous New York City Board of Education, which he called "a rinky-dink candy store." He joined a long list of New York mayors, educators, and business leaders who believed that the city's…

  11. In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

    PubMed

    Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

    2015-04-01

    Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications. PMID:25731092

  12. Advanced characterization study of commercial conversion and electrocoating structures on magnesium alloys AZ31B and ZE10A

    DOE PAGES

    Brady, Michael P.; Leonard, Donovan N.; Meyer, III, Harry M.; Song, Guang -Ling; Kitchen, Kris; Davis, Bruce; Thompson, J. K.; Unocic, K. A.; Elsentriecy, H. H.

    2016-03-31

    The local metal-coating interface microstructure and chemistry formed on commercial magnesium alloys Mg–3Al–1Zn (AZ31B) and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A, ZEK100 type) were analyzed as-chemical conversion coated with a commercial hexafluoro-titanate/zirconate type + organic polymer based treatment (Bonderite® 5200) and a commercial hexafluoro-zirconate type + trivalent chromium Cr3 + type treatment (Surtec® 650), and after the same conversion coatings followed by electrocoating with an epoxy based coating, Cathoguard® 525. Characterization techniques included scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cross-section scanning transmission electron microscopy (STEM). Corrosion behavior was assessed in room temperature saturated aqueous Mg(OH)2 solution with 1 wt.% NaCl. Themore » goal of the effort was to assess the degree to which substrate alloy additions become enriched in the conversion coating, and how the conversion coating was impacted by subsequent electrocoating. Key findings included the enrichment of Al from AZ31B and Zr from ZE10A, respectively, into the conversion coating, with moderate corrosion resistance benefits for AZ31B when Al was incorporated. Varying degrees of increased porosity and modification of the initial conversion coating chemistry at the metal-coating interface were observed after electrocoating. These changes were postulated to result in degraded electrocoating protectiveness. As a result, these observations highlight the challenges of coating Mg, and the need to tailor electrocoating in light of potential degradation of the initial as-conversion coated Mg alloy surface.« less

  13. In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

    PubMed

    Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

    2015-04-01

    Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications.

  14. Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

    2015-10-01

    A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

  15. Assessment of pesticide residues in Karaboğaz Lake from Kızılırmak Delta, Turkey.

    PubMed

    Yurtkuran, Zeynep; Saygı, Yasemin

    2013-08-01

    Monitoring of pesticide residues in water and sediments was conducted for the coastal shallow Karaboğaz Lake, northern Turkey. During a one-year study period, eight pesticides (malathion, etofenprox, molinate, oxamyl, propamocarb hydrochloride, tebufenozide, linuron, piperonyl butoxide) were detected in water and in sediments, all at μg/L and μg/kg concentrations, respectively. Temporal variation in pesticide concentrations was observed. Highest pesticide concentrations in water and sediment were from tebufenozide and etofenprox, respectively. Aquatic risk assessments revealed that out of eight pesticides detected, three showed unaccaptable risk: malathion, oxamyl and etofenprox.

  16. A tale of two machines: a review of the BLAST meeting, Tucson, AZ, 20-24 January 2013.

    PubMed

    Josenhans, Christine; Jung, Kirsten; Rao, Christopher V; Wolfe, Alan J

    2014-01-01

    Since its inception, Bacterial Locomotion and Signal Transduction (BLAST) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. At the 12th BLAST meeting, held last January in Tucson, AZ, researchers from all over the world met to report and discuss progress in diverse aspects of the field. The majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. This was especially true of the biological machines that sense and respond to environmental changes.

  17. SUBMILLIMETER ARRAY IDENTIFICATION OF THE MILLIMETER-SELECTED GALAXY SSA22-AzTEC1: A PROTOQUASAR IN A PROTOCLUSTER?

    SciTech Connect

    Tamura, Y.; Iono, D.; Hatsukade, B.; Kawabe, R.; Wilner, D. J.; Chung, A.; Kajisawa, M.; Hayashino, T.; Ichikawa, T.; Uchimoto, Y. K.; Ikarashi, S.; Kohno, K.; Alexander, D. M.; Lehmer, B. D.; Matsuda, Y.; Ezawa, H.; Nakanishi, K.; Takata, T.; Hughes, D. H.; Wilson, G. W.

    2010-12-01

    We present results from Submillimeter Array (SMA) 860 {mu}m subarcsecond astrometry and multiwavelength observations of the brightest millimeter (S{sub 1.1mm} = 8.4 mJy) source, SSA22-AzTEC1, found near the core of the SSA22 protocluster that is traced by Ly{alpha}-emitting galaxies at z = 3.09. We identify a 860 {mu}m counterpart with a flux density of S{sub 860{sub {mu}m}} = 12.2 {+-} 2.3 mJy and absolute positional accuracy that is better than 0.''3. At the SMA position, we find radio-to-mid-infrared counterparts, whilst no object is found in Subaru optical and near-infrared deep images at wavelengths {<=}1 {mu}m (J > 25.4 in AB, 2{sigma}). The photometric redshift estimate, using flux densities at {>=}24 {mu}m, indicates z{sub phot} = 3.19{sup +0.26}{sub -0.35}, consistent with the protocluster redshift. We then model the near-to-mid-infrared spectral energy distribution (SED) of SSA22-AzTEC1, and find that the SED modeling requires a large extinction (A{sub V} {approx} 3.4 mag) of starlight from a stellar component with M{sub star} {approx} 10{sup 10.9} M{sub sun}, assuming z = 3.1. Additionally, we find a significant X-ray counterpart with a very hard spectrum ({Gamma}{sub eff} = -0.34{sup +0.57}{sub -0.61}), strongly suggesting that SSA22-AzTEC1 harbors a luminous active galactic nuclei (AGNs; L{sub X} {approx} 3 x 10{sup 44} erg s{sup -1}) behind a large hydrogen column (N{sub H} {approx} 10{sup 24} cm{sup -2}). The AGN, however, is responsible for only {approx}10% of the bolometric luminosity of the host galaxy, and therefore the star formation activity likely dominates the submillimeter emission. It is possible that SSA22-AzTEC1 is the first example of a protoquasar growing at the bottom of the gravitational potential underlying the SSA22 protocluster.

  18. Wetting and Interfacial Characteristics of Mg AZ61 Alloy/Galvanized Steel in Cold Metal Transfer Process

    NASA Astrophysics Data System (ADS)

    Lin, Qiaoli; Yang, Fan; Cao, Rui; Chen, Jianhong; Guo, Tingbiao

    2015-09-01

    The dynamic sessile drop method was used to study the wetting behavior of galvanized steel by molten Mg AZ61 alloy under cold metal transfer condition. The interfacial microstructures were also analyzed by using scanning electron microscope and energy dispersive spectrometry. The observed results showed that the wetting behavior was directly determined by the wire feed speed (or the heat input). The Al-Fe intermetallic layer and Zn-rich zone were observed both at the interface and at the close of triple line. The formations of these interfacial characteristics satisfy the thermodynamic characteristic of Mg-Al/Fe and Mg-Zn/Fe systems.

  19. Diffusion Bonding Behavior and Characterization of Joints Made Between 316L Stainless Steel Alloy and AZ31 Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Elthalabawy, Waled Mohamed

    The 316L austenitic stainless steel and AZ31 magnesium alloy have physical and mechanical properties which makes these alloys suitable in a number of high technology based industries such as the aerospace and automotive sectors. However, for these alloys to be used in engineering applications, components must be fabricated and joined successfully. The differences in the physical and metallurgical properties between these two alloys prevents the use of conventional fusion welding processes commonly employed in aerospace and transport industry. Therefore, alternative techniques need to be developed and diffusion bonding technology is a process that has considerable potential to join these two dissimilar alloys. In this research work both solid-state and transient liquid phase (TLP) bonding processes were applied. The solid-state bonding of 316L steel to AZ31 magnesium alloy was possible at a bonding temperature of 550°C for 120 minutes using a pressure of 1.3 MPa. The interface characterization of the joint showed a thin intermetallic zone rich in Fe-Al was responsible for providing a metallurgical bond. However, low joint shear strengths were recorded and this was attributed to the poor surface to surface contact. The macro-deformation of the AZ31 alloy prevented the use of higher bonding pressures and longer bonding times. In order to overcome these problems, the TLP bonding process was implemented using pure Cu and Ni foils as interlayers which produced a eutectic phase at the bonding temperature. This research identified the bonding mechanism through microstructural and differential scanning calorimetry investigations. The microstructural characterization of the TLP joints identified intermetallics which became concentrated along the 316L steel/AZ31 bond interface due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The size and concentration of the intermetallics had a noticeable effect on the final joint

  20. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

    NASA Astrophysics Data System (ADS)

    Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

    2016-06-01

    The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

  1. Complete Mitochondrial and Plastid Genomes of the Green Microalga Trebouxiophyceae sp. Strain MX-AZ01 Isolated from a Highly Acidic Geothermal Lake

    PubMed Central

    Martínez-Romero, Esperanza

    2012-01-01

    We report the complete organelle genome sequences of Trebouxiophyceae sp. strain MX-AZ01, an acidophilic green microalga isolated from a geothermal field in Mexico. This eukaryote has the remarkable ability to thrive in a particular shallow lake with emerging hot springs at the bottom, extremely low pH, and toxic heavy metal concentrations. Trebouxiophyceae sp. MX-AZ01 represents one of few described photosynthetic eukaryotes living in such a hostile environment. The organelle genomes of Trebouxiophyceae sp. MX-AZ01 are remarkable. The plastid genome sequence currently presents the highest G+C content for a trebouxiophyte. The mitochondrial genome sequence is the largest reported to date for the Trebouxiophyceae class of green algae. The analysis of the genome sequences presented here provides insight into the evolution of organelle genomes of trebouxiophytes and green algae. PMID:23104370

  2. Complete mitochondrial and plastid genomes of the green microalga Trebouxiophyceae sp. strain MX-AZ01 isolated from a highly acidic geothermal lake.

    PubMed

    Servín-Garcidueñas, Luis E; Martínez-Romero, Esperanza

    2012-11-01

    We report the complete organelle genome sequences of Trebouxiophyceae sp. strain MX-AZ01, an acidophilic green microalga isolated from a geothermal field in Mexico. This eukaryote has the remarkable ability to thrive in a particular shallow lake with emerging hot springs at the bottom, extremely low pH, and toxic heavy metal concentrations. Trebouxiophyceae sp. MX-AZ01 represents one of few described photosynthetic eukaryotes living in such a hostile environment. The organelle genomes of Trebouxiophyceae sp. MX-AZ01 are remarkable. The plastid genome sequence currently presents the highest G+C content for a trebouxiophyte. The mitochondrial genome sequence is the largest reported to date for the Trebouxiophyceae class of green algae. The analysis of the genome sequences presented here provides insight into the evolution of organelle genomes of trebouxiophytes and green algae.

  3. Martian City Map

    NASA Technical Reports Server (NTRS)

    2004-01-01

    30 May 2004 Seasonal frost can enhance the view from orbit of polar polygonal patterns on the surface of Mars. Sometimes these patterns look something like a city map, or the view from above a city lit-up at night. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example from the south polar region near 80.7oS, 70.6oW. Polar polygons on Mars are generally believed, though not proven, to be the result of freeze/thaw cycles of ice occurring within the upper few meters (several yards) of the martian subsurface. The image shown here covers an area about 3 km (1.9 mi) across; sunlight illuminates the scene from the upper left.

  4. Garden City, Kansas

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Center pivot irrigation systems create red circles of healthy vegetation in this image of croplands near Garden City, Kansas. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on September 25, 2000. This is a false-color composite image made using near infrared, red, and green wavelengths. The image has also been sharpened using the sensor's panchromatic band. Image provided by the USGS EROS Data Center Satellite Systems Branch

  5. Asthma in inner cities.

    PubMed Central

    LeNoir, M. A.

    1999-01-01

    While the management of asthma has improved over the past two decades, the incidence of asthma in the inner city has not. The inner city, comprising a disproportionate number of people who live close to or below the poverty line, shows increased rates of morbidity and mortality from asthma. African Americans and Hispanic Americans are two to six times more likely to die from asthma than their white counterparts. When federally funded programs have targeted reducing morbidity and mortality in children from these populations, they have succeeded, but in a national study only 18 states had initiatives targeting asthma in low-income populations. This is tantamount to a public health crisis. Patients are not always properly diagnosed and are often without a regular source of health care, and symptoms are seen only in an acute context. Living conditions for the inner-city child have significant allergen triggers associated with house dust, cockroaches, cigarette smoke, chemical pollutants, and particulate matter. Viral infections, such as those caused by respiratory syncytial virus, are worse in crowded living conditions. The desirability of an increased public awareness of the seriousness of the disease and the need for chronic health care are issues that should be raised, through culturally relevant public means and in the knowledge that visual information is most effective. Physicians must understand the proper use of rescue and controller drugs, and asthma education must expand beyond doctors and nurses in their offices. The National Medical Association is committed to doing this aggressively, and community organizations, alliances, and coalitions must also aggressively follow. Public agencies must be lobbied to set high standards for proper asthma care and resources. With organizations acting in concert, the mortality and morbidity from asthma can be substantially prevented in the inner city. PMID:12653387

  6. Human diffusion and city influence

    PubMed Central

    Lenormand, Maxime; Gonçalves, Bruno; Tugores, Antònia; Ramasco, José J.

    2015-01-01

    Cities are characterized by concentrating population, economic activity and services. However, not all cities are equal and a natural hierarchy at local, regional or global scales spontaneously emerges. In this work, we introduce a method to quantify city influence using geolocated tweets to characterize human mobility. Rome and Paris appear consistently as the cities attracting most diverse visitors. The ratio between locals and non-local visitors turns out to be fundamental for a city to truly be global. Focusing only on urban residents' mobility flows, a city-to-city network can be constructed. This network allows us to analyse centrality measures at different scales. New York and London play a central role on the global scale, while urban rankings suffer substantial changes if the focus is set at a regional level. PMID:26179991

  7. Human diffusion and city influence.

    PubMed

    Lenormand, Maxime; Gonçalves, Bruno; Tugores, Antònia; Ramasco, José J

    2015-08-01

    Cities are characterized by concentrating population, economic activity and services. However, not all cities are equal and a natural hierarchy at local, regional or global scales spontaneously emerges. In this work, we introduce a method to quantify city influence using geolocated tweets to characterize human mobility. Rome and Paris appear consistently as the cities attracting most diverse visitors. The ratio between locals and non-local visitors turns out to be fundamental for a city to truly be global. Focusing only on urban residents' mobility flows, a city-to-city network can be constructed. This network allows us to analyse centrality measures at different scales. New York and London play a central role on the global scale, while urban rankings suffer substantial changes if the focus is set at a regional level.

  8. Human diffusion and city influence.

    PubMed

    Lenormand, Maxime; Gonçalves, Bruno; Tugores, Antònia; Ramasco, José J

    2015-08-01

    Cities are characterized by concentrating population, economic activity and services. However, not all cities are equal and a natural hierarchy at local, regional or global scales spontaneously emerges. In this work, we introduce a method to quantify city influence using geolocated tweets to characterize human mobility. Rome and Paris appear consistently as the cities attracting most diverse visitors. The ratio between locals and non-local visitors turns out to be fundamental for a city to truly be global. Focusing only on urban residents' mobility flows, a city-to-city network can be constructed. This network allows us to analyse centrality measures at different scales. New York and London play a central role on the global scale, while urban rankings suffer substantial changes if the focus is set at a regional level. PMID:26179991

  9. Is a healthy city also an age-friendly city?

    PubMed

    Jackisch, Josephine; Zamaro, Gianna; Green, Geoff; Huber, Manfred

    2015-06-01

    Healthy Ageing is an important focus of the European Healthy Cities Network and has been supported by WHO since 2003 as a key strategic topic, since 2010 in cooperation with the Global Network of Age-friendly Cities and Communities. Based on the methodology of realist evaluation, this article synthesizes qualitative evidence from 33 structured case studies (CS) from 32 WHO European Healthy Cities, 72 annual reports from Network cities and 71 quantitative responses to a General Evaluation Questionnaire. City cases are assigned to three clusters containing the eight domains of an age-friendly city proposed by WHO's Global Age-friendly City Guide published in 2007. The analysis of city's practice and efforts in this article takes stock of how cities have developed the institutional prerequisites and processes necessary for implementing age-friendly strategies, programmes and projects. A content analysis of the CS maps activities across age-friendly domains and illustrates how cities contribute to improving the social and physical environments of older people and enhance the health and social services provided by municipalities and their partners.

  10. RARγ is required for correct deposition and removal of Suz12 and H2A.Z in embryonic stem cells

    PubMed Central

    Amat, Ramon; Gudas, Lorraine J.

    2012-01-01

    Retinoic acid (RA) induces embryonic stem cell differentiation. The effects of RA are mediated by retinoic acid receptors (RARs) that promote epigenetic changes controlling gene transcription. We show here that RARγ, in the absence of the ligand RA, is required for deposition of the histone variant H2A.Z and the Polycomb protein Suz12 at RA target genes, and that both RARγ and Suz12 exist in a multi-protein complex in the absence of ligand. Addition of RA causes removal of H2A.Z and Suz12 from RARγ target genes when the genes are transcriptionally activated. PMID:20857416

  11. In vitro degradation, cytocompatibility and hemolysis tests of CaF2 doped TiO2-SiO2 composite coating on AZ31 alloy

    NASA Astrophysics Data System (ADS)

    Li, Bing; Chen, Yun; Huang, Wei; Yang, Wenzhong; Yin, Xiaoshuang; Liu, Ying

    2016-09-01

    In this study, a CaF2 doped TiO2-SiO2 composite coating was successfully coated onto AZ31 alloy by sol-gel method. Electrochemical tests, in vitro degradation, direct cellular experiment and hemolysis tests were conducted and the results showed that the CaF2 doped TiO2-SiO2 composite coating can not only improve the corrosion resistance, but also enhance the biocompatibility of AZ31 alloy. XRD, SEM and EDX were also performed to characterize the crystalline structures, morphologies and chemical compositions of the coatings.

  12. Flash Floods, Sediment Transport, and the Geomorphic Transformation of Moenkopi Wash, AZ

    NASA Astrophysics Data System (ADS)

    Dean, D. J.; Topping, D. J.

    2015-12-01

    Fine sediment is a crucial resource to the Colorado River ecosystem in Grand Canyon National Park, AZ. Much of the fine sediment is supplied during flash floods on the Little Colorado River (LCR) and its tributary, Moenkopi Wash (MW). Concentrations of suspended-sediment during flash floods on MW are often greater than 200,000 mg/L, and have exceeded 490,000 mg/L. Historically, the highest concentrations of suspended-sand measured in the LCR have been the result of flooding on MW. Over the last 65 years, widespread geomorphic change on MW has occurred that has likely altered the amount of fine sediment supplied to the LCR. Geomorphic changes include channel-bed aggradation, channel narrowing, increases in sinuosity, and non-native vegetation colonization of the banks and floodplains. Channel-bed aggradation has exceeded 2m, and the channel has narrowed by more than 66% in some areas. In these areas, the combination of aggradation and narrowing has resulted in the loss of cross-section area by nearly 90%. The direct causes of these changes are unclear and may include changes in stream flow and sediment supply caused by human activities and/or climate, and the increased sediment trapping efficiency of vegetation. However, the causes are likely a complex combination of all of the above. Although stream gages have existed on Moenkopi Wash since 1926, frequent changes in gaging locations combined with substantial flood attenuation during flash floods make it difficult to compile a long-term flow record at a single location. Therefore, we are using a kinematic-wave model to route floods between the historic gaging locations in order to construct a long-term flow record near the mouth of Moenkopi Wash. Analyses of the long-term flow record, combined with analyses of suspended-sediment transport are used to evaluate how the geomorphic transformation of Moenkopi Wash has affected sediment delivery to the Little Colorado and the Colorado Rivers.

  13. A Remotely Sensed and Paleomagnetic Perspective on the Bonelli Tuff of NW AZ and SE CA

    NASA Astrophysics Data System (ADS)

    Gomez, C. D.

    2015-12-01

    The southern Black and Cerbat Mountains of NW AZ and the Sacramento Mountains of SE CA preserve ignimbrites associated with multiple episodes of volcanic activity that span at least a million years. Unraveling the stratrigraphy of these deposits, as well as their eruptive centers, is critical for constraining the volcanic history of this ignimbrite, the 18.8 Ma Peach Spring Tuff, is the recently identified 17.7 Ma Tuff of Bonelli House (TB) (Ferguson & Cook 2015) and may also occur in the southern Black and Sacramento Mountains. To help determine the extent and possible source of the TB, we have performed a combined remote sensing and paleomagnetic study of this unit, including possible correlatives. Paleomagnetic work involved Remanence and anisotropic magnetic susceptibility methods. Drill samples were collected and processed at Scripps Institute of Oceanography & Pomona College. An AC current was run to obtain the Paleomag current, as opposed to the traditional of heating up the cores at specific intervals. Sacramento Mountains samples produced an average direction of 200.9 / -26.4, which contrasts the Peach Spring Tuff paleodirection of 036.4/33 (Wells & Hillhouse, 1989). An AMS direction was determined using a MFK1 Kappabridge instrument and consistently showed similar flow direction to that of the PST. In compiling our data on a map, we took into account the Whipple Detachment Fault, ~40 km westward (Lister & Davis, 1989). We were able to identify a spectral signature and remnant paleomagnetic direction for the TB and identify potential additional outcrops in the southern Black mountains. AMS showed us that the ignimbrites originated from a source in the Silver Creek Caldera, which may indicate the PST at TB were produced from a similar source. The remnant paleomagnetic direction allows us to closely correlate these tuff units as occurring within a similar timeframe. The contrasting paleodirection of the TB and the PST allows us to confidently say that the

  14. Source-zone characterization of a chlorinated-solvent contaminated Superfund site in Tucson, AZ.

    PubMed

    Brusseau, M L; Nelson, N T; Zhang, Z; Blue, J E; Rohrer, J; Allen, T

    2007-02-20

    An extensive site-characterization project was conducted at a large chlorinated-solvent contaminated Superfund site in Tucson, AZ. The project consisted of several components, including traditional site-characterization activities, tracer tests, laboratory experiments conducted with core material collected from the site, and mathematical modeling. The primary focus of the work presented herein is the analysis of induced-gradient contaminant elution tests conducted in a source zone at the site, investigation of the potential occurrence of immiscible liquid in the saturated zone, characterization of the relationship between mass flux reduction and mass removal, and evaluation of the impact of source-zone management on site remediation. The results of the present study, along with those of prior work, indicate that immiscible liquid is likely present in the saturated zone at the site source zones. Extensive tailing and rebound was observed for the contaminant-elution tests, indicating nonideal transport and mass-transfer behavior. The elution data were analyzed with a source-zone-scale mathematical model, and the results indicated that nonideal immiscible-liquid dissolution was the primary cause of the observed behavior. The time-continuous relationship between mass flux reduction and mass removal associated with the plume-scale pump-and-treat operation exhibited an initial large drop in mass flux with minimal mass removed, followed by a period of minimal mass flux reduction and a second period of large reduction. This behavior reflects the impact of both source-zone and aqueous-plume mass removal dynamics. Ultimately, a greater than 90% reduction in mass flux was achieved for a mass removal of approximately 50%. The influence of source-zone management on site remediation was evaluated by conducting two predictive simulations, one for which the source zones were controlled and one for which they were not. A plume-scale model was used to simulate the composite

  15. Alt-Az telescope control system standardization attempt: case study of the TT1 (Toppo Telescope #1) control system

    NASA Astrophysics Data System (ADS)

    Mancini, Dario; Brescia, Massimo; Spirito, Gianfranco

    1998-05-01

    The TT1 is a 1.54 m Alt-Az telescope designed and built by the Technology Working Group of the Astronomical Observatory of Capodimonte, Naples, Italy. The standardization process is of course one of the fundamental requirements for telescope control system design and development, well considered in the TT1 design. In this paper we present the approach used to identify a control system applicable to medium-size Alt-Az telescope. The TT1 control system architecture is based on a distributed working flow and it is PC-based, i.e. organized in several interconnected standard PCs and standard fast communication protocol. Every PC is based on the 'dedicated processing unit' concept and it makes real time own tasks independently by other units. Also, the extremely reduced communication flow between PCs, and the internal organization based on the preference given to software rather than hardware solutions, makes its control system extremely reliable, easily reconfigurable and upgradable, obsolescence deprived and independent from any hardware choice.

  16. Poly(L-lactic acid)/hydroxyapatite/collagen composite coatings on AZ31 magnesium alloy for biomedical application.

    PubMed

    Wang, Zhen-Lin; Yan, Yu-Hua; Wan, Tao; Yang, Hui

    2013-10-01

    Surface modification of biomedical magnesium alloy using composite coating shows an attemptable approach for the development of Mg-based biomaterials with excellent cytocompatibility. Hydroxyapatite/collagen composite was preliminarily fabricated by biomineralization, the bioactive poly(l-lactic acid)/hydroxyapatite/collagen composite coatings were spin coated on AZ31 magnesium alloy using poly(l-lactic acid) solution mixed with hydroxyapatite/collagen particles, and the resultant materials and coatings were characterized in structure and related properties; furthermore, the in vitro degradation behavior of modified magnesium alloy in 1.5-fold Hank's solution was investigated. The results show that hydroxyapatite/collagen composite achieved chemical bonding between hydroxyapatite and collagen similar to natural bone; composite coatings on AZ31 magnesium alloy retained the bioactive functional groups of the componential materials and improved the corrosion resistance of Mg alloy; the mass fraction of hydroxyapatite/collagen particles incorporated into the composite affected the porous structure, interfacial adhesion and thus the corrosion resistance of the composite coating due to phase separation as well as volume concentration effects of polymer solution. Composite coatings suppressed the sharp rising of pH value and the released Mg(2+) from substrate to extensive degree, and the degradation behavior of the modified magnesium alloy was supposed to be correlated to microstructure of the coating as well as the synergistic reactions among alkaline- and acidic-degraded products.

  17. Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

    SciTech Connect

    Asgari, H.; Odeshi, A.G.; Szpunar, J.A.; Zeng, L.J.; Olsson, E.

    2015-08-15

    The effects of grain size on the dynamic deformation behavior of rolled AZ31B alloy at high strain rates were investigated. Rolled AZ31B alloy samples with grain sizes of 6, 18 and 37 μm, were subjected to shock loading tests using Split Hopkinson Pressure Bar at room temperature and at a strain rate of 1100 s{sup −} {sup 1}. It was found that a double-peak basal texture formed in the shock loaded samples. The strength and ductility of the alloy under the high strain-rate compressive loading increased with decreasing grain size. However, twinning fraction and strain hardening rate were found to decrease with decreasing grain size. In addition, orientation imaging microscopy showed a higher contribution of double and contraction twins in the deformation process of the coarse-grained samples. Using transmission electron microscopy, pyramidal dislocations were detected in the shock loaded sample, proving the activation of pyramidal slip system under dynamic impact loading. - Highlights: • A double-peak basal texture developed in all shock loaded samples. • Both strength and ductility increased with decreasing grain size. • Twinning fraction and strain hardening rate decreased with decreasing grain size. • ‘g.b’ analysis confirmed the presence of dislocations in shock loaded alloy.

  18. H2A.Z controls the stability and mobility of nucleosomes to regulate expression of the LH genes

    PubMed Central

    Rudnizky, Sergei; Bavly, Adaiah; Malik, Omri; Pnueli, Lilach; Melamed, Philippa; Kaplan, Ariel

    2016-01-01

    The structure and dynamics of promoter chromatin have a profound effect on the expression levels of genes. Yet, the contribution of DNA sequence, histone post-translational modifications, histone variant usage and other factors in shaping the architecture of chromatin, and the mechanisms by which this architecture modulates expression of specific genes are not yet completely understood. Here we use optical tweezers to study the roles that DNA sequence and the histone variant H2A.Z have in shaping the chromatin landscape at the promoters of two model genes, Cga and Lhb. Guided by MNase mapping of the promoters of these genes, we reconstitute nucleosomes that mimic those located near the transcriptional start site and immediately downstream (+1), and measure the forces required to disrupt these nucleosomes, and their mobility along the DNA sequence. Our results indicate that these genes are basally regulated by two distinct strategies, making use of H2A.Z to modulate separate phases of transcription, and highlight how DNA sequence, alternative histone variants and remodelling machinery act synergistically to modulate gene expression. PMID:27653784

  19. The Effect of SiC Particle Addition During FSW on Microstructure and Mechanical Properties of AZ31 Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Abbasi, M.; Abdollahzadeh, A.; Bagheri, B.; Omidvar, H.

    2015-12-01

    Welding and joining of magnesium alloys exert a profound effect on magnesium application expansion, especially in ground and air transportations where large-size, complex components are required. Due to specific physical properties of magnesium, its welding requires great control. In general, the solid-state nature of friction stir welding (FSW) process has been found to produce a low concentration of defects. In the current research, specimens from AZ31 magnesium alloy were welded together using the friction stir process with previously inserted SiC powder particles in the nugget zone. In other words, during the FSW process, the pre-placed SiC particles were stirred throughout the nugget zone of the weld. The results indicated that proper values of rotation and translation speeds led to good appearance of weld zone and suitable distribution of SiC particles producing increased weld strength. The comparison of the microstructures and mechanical properties of FS-welded AZ31 with those of FS-welded one using pre-placed SiC particles showed that the addition of SiC particles decreased the grain size and increased the strength and the formability index.

  20. Darkening effect on AZ31B magnesium alloy surface induced by nanosecond pulse Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Guan, Y. C.; Zhou, W.; Zheng, H. Y.; Li, Z. L.

    2013-09-01

    Permanent darkening effect was achieved on surface of AZ31B Mg alloy irradiated with nanosecond pulse Nd:YAG laser, and special attention was made to examine how surface structure as well as oxidation affect the darkening effect. Experiments were carried out to characterize morphological evolution and chemical composition of the irradiated areas by optical reflection spectrometer, Talysurf surface profiler, SEM, EDS, and XPS. The darkening effect was found to be occurred at the surface under high laser energy. Optical spectra showed that the induced darkening surface was uniform over the spectral range from 200 nm to 1100 nm. SEM and surface profiler showed that surface morphology of darkening areas consisted of large number of micron scale cauliflower-like clusters and protruding particles. EDS and XPS showed that compared to non-irradiated area, oxygen content at the darkening areas increased significantly. It was proposed a mechanism that involved trapping of light in the surface morphology and chemistry variation of irradiated areas to explain the laser-induced darkening effect on AZ31B Mg alloy.

  1. Numerical assessment of the role of slip and twinning in magnesium alloy AZ31B during loading path reversal

    SciTech Connect

    Wang, Huamiao; Wu, Peidong; Wang, Jian

    2015-04-17

    Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC–TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension–compression–tension along rolling direction, (2) tension–compression–tension along transverse direction, (3) compression–tension–compression along rolling direction, and (4) compression–tension–compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimental observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Lastly, such significant effect is mainly ascribed to the activity of twinning and detwinning.

  2. Hydroxyapatite coating on biodegradable AZ31 and Mg-Ca alloys prepared by RF-magnetron sputtering

    SciTech Connect

    Mukhametkaliyev, T. Surmeneva, M. Surmenev, R.; Mathan, B. K.

    2015-11-17

    A thin film of hydroxyapatite (HA) was deposited on AZ31 and Mg-Ca alloys by using radio frequency (RF) magnetron sputtering. The thickness of the HA coating was determined to be 750 nm. The phase composition, microstructure, and surface morphology of the HA coatings were investigated using X-ray diffraction and scanning electron microscopy. In vitro degradation behaviour of the HA coated alloys was evaluated in simulated body fluid (SBF) and 3.5wt.% NaCl solution using electrochemical method. The coatings homogeneously covered the entire surface of the substrates. The coating structure corresponded to a nanostructured HA. The ultrathin coating significantly improved the degradation resistance of the alloy. Nanocrystalline HA coating significantly improved the corrosion resistance of the Mg-Ca and AZ31 magnesium alloys. The polarization resistance (Rp) of the coated Mg-Ca alloy was more than two-order of magnitude higher and the corrosion current density I{sub corr} reduced by ∼ 98% as compared to the base alloy.

  3. Nucleosome free region dominates histone acetylation in targeting SWR1 to yeast promoters for H2A.Z replacement

    PubMed Central

    Ranjan, Anand; Mizuguchi, Gaku; FitzGerald, Peter C.; Wei, Debbie; Wang, Feng; Huang, Yingzi; Luk, Ed; Woodcock, Christopher L; Wu, Carl

    2013-01-01

    Summary The histone variant H2A.Z is a genome-wide signature of nucleosomes proximal to eukaryotic regulatory DNA. While the multi-subunit chromatin remodeler SWR1 is known to catalyze ATP-dependent deposition of H2A.Z, the mechanism of SWR1 recruitment to S. cerevisiae promoters has been unclear. A sensitive assay for competitive binding of di-nucleosome substrates revealed that SWR1 preferentially binds long nucleosome-free DNA and the adjoining nucleosome core particle, allowing discrimination of gene promoters over gene bodies. Analysis of mutants indicates that the conserved Swc2/YL1 subunit and the ATPase domain of Swr1 are mainly responsible for binding to substrate. SWR1 binding is enhanced on nucleosomes acetylated by the NuA4 histone acetyltransferase, but recognition of nucleosome-free and nucleosomal DNA is dominant over interaction with acetylated histones. Such hierarchical cooperation between DNA and histone signals expands the dynamic range of genetic switches, unifying classical gene regulation by DNA-binding factors with ATP-dependent nucleosome remodeling and post-translational histone modifications. PMID:24034247

  4. Simulation of AZ-PN100 Resist Pattern Fluctuation in X-Ray Lithography, Including Synchrotron Beam Polarization

    NASA Astrophysics Data System (ADS)

    Scheckler, Edward W.; Ogawa, Taro; Tanaka, Toshihiko; Oizumi, Hiroaki; Takeda, Eiji

    1993-12-01

    A new simulation model for nanometer-scale pattern fluctuation in X-ray lithography is presented and applied to a study of AZ-PN100 negative chemical amplification resist. The exposure simulation considers polarized photons from a synchrotron radiation (SR) source. Monte Carlo simulation of Auger and photoelectron generation is followed by electron scattering simulation to determine the deposited energy distribution at the nanometer scale, including beam polarization effects. An acid-catalyst random walk model simulates the post-exposure bake (PEB) step. Fourier transform infrared (FTIR) spectroscopy and developed resist thickness measurements are used to fit PEB and rate models for AZ-PN100. A polymer removal model for development simulation predicts the macroscopic resist shape and pattern roughness. The simulated 3σ linewidth variation is in excess of 24 nm. Simulation also shows a detrimental effect if the beam polarization is perpendicular to the line. Simulation assuming a theoretical ideal exposure yields a 50 nm minimum line for standard process conditions.

  5. Simulating Intergranular Stress Corrosion Cracking in AZ31 Using Three-Dimensional Cohesive Elements for Grain Structure

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Chen, Z. H.; Dong, C. F.

    2015-12-01

    In this study, a grain boundary model with three-dimensional (3D) cohesive elements for analyzing the intergranular stress corrosion cracking (IGSCC) on the crystal level in polycrystalline materials is presented. The objectives are to characterize the grain boundary microstructure and the fracture mechanism of IGSCC in AZ31 Mg alloy. In order to investigate the development of the microcrack and its effects on macrocrack evolution, a novel model of IGSCC propagation has been developed, in which the 3D Voronoi tessellations geometry is employed to model polycrystalline grain structures. And the 3D cohesive elements with zero constitutive thickness are directly inserted on the faces of two adjacent grains. The effect of the embrittlement due to the presence of hydrogen has also been included in the cohesive model. To validate the model, an IGSCC process of AZ31 Mg alloy in NaCl solution has been simulated, with the influence of hydrogen concentration being taken into account. It is found that damage develops at the triple lines between the grains and the combinations of grains can lead to high stresses at the grains boundary, especially those that are normal to the direction of the applied strain. In this paper, the effects of damage due to hydrogen and the grain sizes in microstructure are considered. The simulation results have a good consistency with the experimental phenomenon.

  6. Rate and Orientation Dependence of Formability in Fine-Grained AZ31B-O Mg Alloy Thin Sheet

    NASA Astrophysics Data System (ADS)

    Wu, Horng-Yu; Sun, Pin-Hou; Chen, Hung-Wei; Chiu, Chui-Hung

    2012-10-01

    Uniaxial tension and press forming tests were carried out at two different strain rates and temperatures to investigate the formability of fine-grained AZ31B-O Mg alloy thin sheet. Formability parameters were determined by tensile test results. The tensile properties and formability parameters were correlated with the forming limit diagrams. The present work focused on the effects of loading orientation and deformation rate on formability. Anisotropic behaviors were observed in the mechanical properties. Maximum strengths were obtained in the direction perpendicular to the rolling direction (RD). It can be concluded that the formability of the rolled fine-grained AZ31B-O Mg alloy sheet can be influenced by loading orientation and deformation rate. Stretch formability can be enhanced at a higher deformation rate, resulting from a lower anisotropy and a higher work hardening effect. In contrast, the drawing processes can be performed at a lower deformation rate to take advantage of a higher anisotropic behavior. Specimens with the RD parallel to the major strain in the press forming tests can enhance stretch formability, whereas specimens with the RD perpendicular to the major strain can improve deep-drawability.

  7. Numerical assessment of the role of slip and twinning in magnesium alloy AZ31B during loading path reversal

    DOE PAGES

    Wang, Huamiao; Wu, Peidong; Wang, Jian

    2015-04-17

    Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC–TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension–compression–tension along rolling direction, (2) tension–compression–tension along transverse direction, (3) compression–tension–compression along rolling direction, and (4) compression–tension–compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimentalmore » observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Lastly, such significant effect is mainly ascribed to the activity of twinning and detwinning.« less

  8. Quantitative Analysis of Composition Change in AZ31 Magnesium Alloy Using CF-LIBS After Laser Material Processing

    NASA Astrophysics Data System (ADS)

    Zhu, Dehua; Cao, Yu; Zhong, Rong; Chen, Xiaojing

    2015-11-01

    The concentration of elements in molten metal of AZ31 magnesium alloy after long pulsed Nd:YAG laser processing was quantitatively analyzed by using calibration-free laser-induced breakdown spectroscopy (CF-LIBS). The composition change in AZ31 magnesium alloy under different laser pulse width was also investigated. The experimental results showed that CF-LIBS can obtain satisfactory quantitative or semi-quantitative results for matrix or major elements, while only qualitative analysis was possible for minor or trace elements. Moreover, it is found that the chemical composition of molten metal will change after laser processing. The concentration of magnesium in molten metal is lower than that present in the base metal. The Mg loss increases with an increase of pulse width in the laser processing. This result shows that the selective vaporization of different elements is affected by the pulse width during laser processing. supported by National Natural Science Foundation of China (Nos. 61405147, 51375348) and the Scientific Research Fund of Zhejiang Provincial Education Department, China (No. Y201430387)

  9. Fluoride ions as modifiers of the oxide layer produced by plasma electrolytic oxidation on AZ91D magnesium alloy

    NASA Astrophysics Data System (ADS)

    Kazanski, Barbara; Kossenko, Alexey; Zinigrad, Michael; Lugovskoy, Alex

    2013-12-01

    Plasma electrolytic oxidation (PEO) is a powerful technique allowing hardening and corrosion protection of valve metals due to formation of an oxide layer on the metal surface. PEO produces much thicker oxide layers as compared to anodizing, which is of critical importance for many technological applications. The present research investigated the influence of the fluoride ion concentration on the composition, structure and morphology of PEO layers on the magnesium alloy AZ91D. The obtained oxide layers were characterized with XRD, SEM, EDS and tested for corrosion resistance by linear sweep voltammetry in 3.5% NaCl medium. During this investigation it was found that KF addition produces significant changes in the structure and properties of the oxide layers. Fluorine was detected as an amorphous phase in the vicinity of the base metal for both alloys and plausible mechanism was suggested to explain these phenomena. Fluoride ions have pronounced catalytic activity and their presence considerably increases the thickness of the oxide layer. Depending on the process parameters, significant improvement of the corrosion stability of AZ91D alloy is achieved by the use of PEO.

  10. Characterization and degradation behavior of AZ31 alloy surface modified by bone-like hydroxyapatite for implant applications

    NASA Astrophysics Data System (ADS)

    Wen, Cuilian; Guan, Shaokang; Peng, Li; Ren, Chenxing; Wang, Xiang; Hu, Zhonghua

    2009-04-01

    Hydroxyapatite (HA) coating on AZ31 alloy substrate was prepared by a cathodic electrodeposition method. The as-deposited specimen was then post-treated with hot alkali solution to improve the corrosion resistance and bioactivity for implant applications. The microstructure and composition of HA coating, as well as its degradation behavior in simulated body fluid (SBF) were investigated. It reveals that the as-deposited coating consists of dicalcium phosphate dehydrate (DCPD, CaHPO 4·2H 2O) and HA. While 10 μm-thick nanowhisker HA coatings doped with Na +, Mg +, HPO 42-and CO 32- can be found after NaOH alkali treatment, which exhibits a very similar composition of natural bone. The post-treated coating was composed of needle-like particles with 1000 nm in length and 35 nm in diameter, having a slenderness ratio of about 28.6. Electrochemical tests shows that the Ecorr of Mg substrate significantly increased from -1.6 to -1.42 V after surface modified by HA coatings. There was obvious mass gain on post-treated specimen immersed in SBF during the first 30 days due to the Ca-P-Mg deposition. The HA-coated AZ31 alloy could slow down the degradation rate and effectively induce the deposition of Ca-P-Mg apatite in SBF, showing a good bioactivity.

  11. Large cities are less green

    PubMed Central

    Oliveira, Erneson A.; Andrade, José S.; Makse, Hernán A.

    2014-01-01

    We study how urban quality evolves as a result of carbon dioxide emissions as urban agglomerations grow. We employ a bottom-up approach combining two unprecedented microscopic data on population and carbon dioxide emissions in the continental US. We first aggregate settlements that are close to each other into cities using the City Clustering Algorithm (CCA) defining cities beyond the administrative boundaries. Then, we use data on CO2 emissions at a fine geographic scale to determine the total emissions of each city. We find a superlinear scaling behavior, expressed by a power-law, between CO2 emissions and city population with average allometric exponent β = 1.46 across all cities in the US. This result suggests that the high productivity of large cities is done at the expense of a proportionally larger amount of emissions compared to small cities. Furthermore, our results are substantially different from those obtained by the standard administrative definition of cities, i.e. Metropolitan Statistical Area (MSA). Specifically, MSAs display isometric scaling emissions and we argue that this discrepancy is due to the overestimation of MSA areas. The results suggest that allometric studies based on administrative boundaries to define cities may suffer from endogeneity bias. PMID:24577263

  12. Large cities are less green.

    PubMed

    Oliveira, Erneson A; Andrade, José S; Makse, Hernán A

    2014-02-28

    We study how urban quality evolves as a result of carbon dioxide emissions as urban agglomerations grow. We employ a bottom-up approach combining two unprecedented microscopic data on population and carbon dioxide emissions in the continental US. We first aggregate settlements that are close to each other into cities using the City Clustering Algorithm (CCA) defining cities beyond the administrative boundaries. Then, we use data on CO2 emissions at a fine geographic scale to determine the total emissions of each city. We find a superlinear scaling behavior, expressed by a power-law, between CO2 emissions and city population with average allometric exponent β = 1.46 across all cities in the US. This result suggests that the high productivity of large cities is done at the expense of a proportionally larger amount of emissions compared to small cities. Furthermore, our results are substantially different from those obtained by the standard administrative definition of cities, i.e. Metropolitan Statistical Area (MSA). Specifically, MSAs display isometric scaling emissions and we argue that this discrepancy is due to the overestimation of MSA areas. The results suggest that allometric studies based on administrative boundaries to define cities may suffer from endogeneity bias.

  13. Large cities are less green

    NASA Astrophysics Data System (ADS)

    Oliveira, Erneson A.; Andrade, José S.; Makse, Hernán A.

    2014-02-01

    We study how urban quality evolves as a result of carbon dioxide emissions as urban agglomerations grow. We employ a bottom-up approach combining two unprecedented microscopic data on population and carbon dioxide emissions in the continental US. We first aggregate settlements that are close to each other into cities using the City Clustering Algorithm (CCA) defining cities beyond the administrative boundaries. Then, we use data on CO2 emissions at a fine geographic scale to determine the total emissions of each city. We find a superlinear scaling behavior, expressed by a power-law, between CO2 emissions and city population with average allometric exponent β = 1.46 across all cities in the US. This result suggests that the high productivity of large cities is done at the expense of a proportionally larger amount of emissions compared to small cities. Furthermore, our results are substantially different from those obtained by the standard administrative definition of cities, i.e. Metropolitan Statistical Area (MSA). Specifically, MSAs display isometric scaling emissions and we argue that this discrepancy is due to the overestimation of MSA areas. The results suggest that allometric studies based on administrative boundaries to define cities may suffer from endogeneity bias.

  14. Securing water for the cities.

    PubMed

    Satterthwaite, D

    1993-01-01

    Many cities in developing countries have grown so much that they can no longer provide adequate, sustainable water. Over pumping in Dakar and Mexico City has forced those cities to obtain water from ever more distant sources. In Dakar, the result has been saltwater intrusion. Overpumping has caused Mexico City to sink, in some areas by as much as 9 m, resulting in serious damage to buildings and sewage and drainage pipes. Other cities facing similar water problems are coastal cities in Peru (e.g., Lima), La Rioja and Catamarca in Argentina, cities in Northern Mexico, and cities in dry areas of Africa. For some cities, the problem is not so much ever more distant water supplies but insufficient funds to expand supplies. Bangkok and Jakarta both face saltwater intrusion into their overdrawn aquifers. Even through agriculture is the dominant user of water in most countries, demand concentrated in a small area exhausts local and regional sources and pollutes rivers, lakes, and coasts with untreated human and industrial waste. Most cities in Africa and Asia do not have a sewerage system. Further, most cities do not have the drains to deal with storm water and external floodwater, causing frequent, seasonal flooding. The resulting stagnant water provides breeding grounds for insect vectors of diseases (e.g., malaria). The problems in most cities are a result of poor management, not lack of water. Reducing leaks in existing piped distribution systems from the usual 60% loss of water to leaks to 12% would increase the available water 2-fold. Another way to address water shortages would be commercial, industrial, and recreational use of minimally treated waste water, such as is the case in Madras and Mexico City. Political solutions are needed to resolve inadequate water supply and waste management.

  15. CityGML - Interoperable semantic 3D city models

    NASA Astrophysics Data System (ADS)

    Gröger, Gerhard; Plümer, Lutz

    2012-07-01

    CityGML is the international standard of the Open Geospatial Consortium (OGC) for the representation and exchange of 3D city models. It defines the three-dimensional geometry, topology, semantics and appearance of the most relevant topographic objects in urban or regional contexts. These definitions are provided in different, well-defined Levels-of-Detail (multiresolution model). The focus of CityGML is on the semantical aspects of 3D city models, its structures, taxonomies and aggregations, allowing users to employ virtual 3D city models for advanced analysis and visualization tasks in a variety of application domains such as urban planning, indoor/outdoor pedestrian navigation, environmental simulations, cultural heritage, or facility management. This is in contrast to purely geometrical/graphical models such as KML, VRML, or X3D, which do not provide sufficient semantics. CityGML is based on the Geography Markup Language (GML), which provides a standardized geometry model. Due to this model and its well-defined semantics and structures, CityGML facilitates interoperable data exchange in the context of geo web services and spatial data infrastructures. Since its standardization in 2008, CityGML has become used on a worldwide scale: tools from notable companies in the geospatial field provide CityGML interfaces. Many applications and projects use this standard. CityGML is also having a strong impact on science: numerous approaches use CityGML, particularly its semantics, for disaster management, emergency responses, or energy-related applications as well as for visualizations, or they contribute to CityGML, improving its consistency and validity, or use CityGML, particularly its different Levels-of-Detail, as a source or target for generalizations. This paper gives an overview of CityGML, its underlying concepts, its Levels-of-Detail, how to extend it, its applications, its likely future development, and the role it plays in scientific research. Furthermore, its

  16. Constructing cities, deconstructing scaling laws

    PubMed Central

    Arcaute, Elsa; Hatna, Erez; Ferguson, Peter; Youn, Hyejin; Johansson, Anders; Batty, Michael

    2015-01-01

    Cities can be characterized and modelled through different urban measures. Consistency within these observables is crucial in order to advance towards a science of cities. Bettencourt et al. have proposed that many of these urban measures can be predicted through universal scaling laws. We develop a framework to consistently define cities, using commuting to work and population density thresholds, and construct thousands of realizations of systems of cities with different boundaries for England and Wales. These serve as a laboratory for the scaling analysis of a large set of urban indicators. The analysis shows that population size alone does not provide us enough information to describe or predict the state of a city as previously proposed, indicating that the expected scaling laws are not corroborated. We found that most urban indicators scale linearly with city size, regardless of the definition of the urban boundaries. However, when nonlinear correlations are present, the exponent fluctuates considerably. PMID:25411405

  17. The dynamics of city formation*

    PubMed Central

    Henderson, J. Vernon; Venables, Anthony J.

    2013-01-01

    This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention. PMID:25089087

  18. City of Paris, France

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This highly detailed view of the City of Paris 49.0N, 0.0E) shows a varied land use pattern in great detail. Several airports are clearly seen such as the two major international airports of Orly and Le Bourget. Paris was founded in pre-Roman times on an island in the Seine River and continued as a Roman outpost. The easily defensible location was one of the keys to growth. Other factors include easy access by river and the productive hinterland.

  19. AZ17: a new bispecific drug targeting IL-6 and IL-23 with potential clinical use--improves psoriasis in a human xenograft transplantation model.

    PubMed

    Stenderup, Karin; Rosada, Cecilia; Shanebeck, Kurt; Brady, William; Van Brunt, Michael P; King, Gordon; Marelli, Marcello; Slagle, Paul; Xu, Hengyu; Nairn, Natalie W; Johnson, Jeffrey; Wang, Aijun A; Li, Gary; Thornton, Kenneth C; Dam, Tomas N; Grabstein, Kenneth H

    2015-10-01

    Targeting more than one molecule in multifactorial diseases involving several disease mediators may provide improved therapeutic efficacy. Psoriasis is a multifactorial disease in which interleukin (IL)-6 and IL-23 are important disease mediators because they facilitate development of Th17 cells; widely accepted to be associated with psoriasis. To meet the need for new therapeutics, we aimed to create a clinically relevant bispecific drug, by combining the inhibitory properties of anti-IL-6 and anti-IL-23 antibodies, exhibiting high affinity, high stability and the ability to be produced in high yield. The bispecific molecule AZ17 was created by combining high affinity binding domains originating from monoclonal antibodies targeting human IL-6 and IL-23. To allow for high and efficient production, AZ17 was assembled by site-specific bioconjugation from two individual single chain fragment variables that were synthesized separately in Escherichia coli. To improve stability and extend pharmacokinetics, a flexible poly-ethylene glycol molecule was used as linker. In preclinical psoriasis models, AZ17 reduced IL-23-induced ear inflammation and improved psoriasis in a xenograft transplantation model where psoriasis skin is transplanted onto immune-deficient mice. The data presented here suggest AZ17 to be a promising drug candidate in psoriasis and other inflammatory diseases associated with Th17 cell development.

  20. Effect of pre-tension amount on formation accuracy of AZ31 as-extruded profile in warm tension-rotation bending process

    NASA Astrophysics Data System (ADS)

    Xiao, Han; Zhang, Shi-hong; Liu, Jin-song; Cheng, Ming

    2013-05-01

    A warm tension rotation bending process is presented to bend the AZ31 as-extruded profile. The effect of pretension amount on formation accuracy of bent AZ31 as-extruded profile was investigated by using numerical and experimental methods. A 3D elastic-plastic thermo-mechanical coupled finite element model of AZ31 profile in bending process was established and the bending experiments were carried out. The results indicate that pre-tension amounts increasing from 0.2% to 1.1%, the numerical and experimental springback angles of AZ31 bent profile all decrease, the experimental springback angles decrease from 12.5° to 9.8°; the numerical and experimental bending radii all decrease, the experimental bending radii decrease from 95.60 mm to 92.83 mm; the distortion of cross-section increases, the sequencing of distortion levels is the thickness of outside-rib, the thickness of inside-rib, the width of outside of the profile, the width of inside of the profile and the thickness of middle-rib.

  1. Arsenic Removal from Drinking Water by Adsorptive Media - U.S. EPA Demonstration Project at Covered Wells in Tohono O’odham Nation, AZ - Final Performance Evaluation Report

    EPA Science Inventory

    This report documents the activities performed and the results obtained from the arsenic removal treatment technology demonstration project at Covered Wells in Tohono O’odham Nation, AZ. The main objective of the project was to evaluate the effectiveness of AdEdge Technologies’ ...

  2. Analysis of metallic traces from the biodegradation of endomedullary AZ31 alloy temporary implants in rat organs after long implantation times.

    PubMed

    Bodelón, O G; Iglesias, C; Garrido, J; Clemente, C; Garcia-Alonso, M C; Escudero, M L

    2015-08-01

    AZ31 alloy has been tested as a biodegradable material in the form of endomedullary implants in female Wistar rat femurs. In order to evaluate the accumulation of potentially toxic elements from the biodegradation of the implant, magnesium (Mg), aluminium (Al), zinc (Zn), manganese (Mn) and fluorine (F) levels have been measured in different organs such as kidneys, liver, lungs, spleen and brain. Several factors that may influence accumulation have been taken into account: how long the implant has been in place, whether or not the bone is fractured, and the presence of an MgF2 protective coating on the implant. The main conclusions and the clinical relevance of the study have been that AZ31 endomedullary implants have a degradation rate of about 60% after 13 months, which is fully compatible with fracture consolidation. Neither bone fracture nor an MgF2 coating seems to influence the accumulation of trace elements in the studied organs. Aluminium is the only alloying element in this study that requires special attention. The increase in Al recovered from the sampled organs represents 3.95% of the amount contained in the AZ31 implant. Al accumulates in a statistically significant way in all the organs except the brain. All of this suggests that in long-term tests AZ31 may be a suitable material for osteosynthesis. PMID:26238295

  3. Effect of interlayer configurations on joint formation in TLP bonding of Ti-6Al-4V to Mg-AZ31

    NASA Astrophysics Data System (ADS)

    Atieh, A. M.; Khan, T. I.

    2014-06-01

    In this research work, the transient liquid phase (TLP) bonding process was utilized to fabricate joints using thin (20μm) nickel and copper foils placed between two bonding surfaces to help facilitate joint formation. Two joint configurations were investigated, first, Ti-6Al-4V/CuNi/Mg-AZ31 and second, Ti-6Al-4V/NiCu/Mg-AZ3L The effect of bonding time on microstructural developments across the joint and the changes in mechanical properties were studied as a function of bonding temperature and pressure. The bonded specimens were examined by metallographic analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD). In both cases, intermetallic phase of CuMg2 and Mg3AlNi2 was observed inside the joint region. The results show that joint shear strengths for the Ti-6Al-4V/CuNi/Mg-AZ31 setup produce joints with shear strength of 57 MPa compared to 27MPa for joints made using the Ti-6Al-4V/NiCu/Mg-AZ31 layer arrangement.

  4. Wide-field Imaging Survey of Dust Continuum Emissions at lambda = 1.1 mm toward the Chamaeleon and Lupus Regions with AzTEC on ASTE

    SciTech Connect

    Momose, Munetake; Hiramatsu, Masaaki; Tsukagoshi, Takashi; Shimajiri, Yoshito; Ezawa, Hajime; Kawabe, Ryohei; Ikeda, Norio; Kitamura, Yoshimi; Kamegai, Kazuhisa; Saito, Masao

    2009-08-05

    We carried out an imaging survey of dust continuum emissions toward the Chamaeleon and Lupus regions. Observations were made with the 144-element bolometer array camera AzTEC mounted on the 10-meter sub-millimeter telescope ASTE during 2007-2008. The preliminary results of disk search and the cloud structure of Lupus III are presented.

  5. Effect of Y, Sr, and Nd additions on the microstructure and microfracture mechanism of squeeze-cast AZ91-X magnesium alloys

    SciTech Connect

    Lee, S.; Lee, S.H.; Kim, D.H.

    1998-04-01

    This study aims to investigate the effects of Y, Sr, and Nd additions on the microstructure and microfracture mechanism of the four squeeze-cast magnesium alloys based on the commercial AZ91 alloy. Microstructural observation, in situ fracture tests, fractographic observation were conducted on the alloys to clarify the microfracture process. Microstructural analyses indicated that grain refinement could be achieved by small additions of alloying elements, although the discontinuously precipitated Mg{sub 17}Al{sub 12} phases still existed on grain boundaries. From in situ fracture observation of an AZ91-Sr alloy, it was seen that coarse needle-shaped compound particles and Mg{sub 17}Al{sub 12} phases located on the grain boundary provided easy intergranular fracture sites under low stress intensity factor levels, resulting in the drop in toughness. On the other hand, the AZ91-Y and AZ91-Nd alloys showed improved fracture toughness, since deformation and fracture paths proceeded into grains rather than to grain boundaries, as the planar slip bands and twinnings actively developed inside the grains. These findings suggested, on the basis of the well-developed planar slip bands and twinnings, that the small addition of Y or Nd was very effective in improving fracture toughness.

  6. Digging the city

    SciTech Connect

    Paulson, S.L.

    1996-02-01

    For city dwellers and commuters, major construction and repair projects by underground utilities have traditionally meant torn-up streets, detours, snarled traffic, flaring tempers and other urban headaches. For store and business owners, utility projects also have frequently been harmful to the bottom line. Customer parking often is curtailed and deliveries are missed because of street excavations, and business hours may even have to be cut because of interruptions in utility service. But natural gas utilities in major cities across the country are working hard to change that reality. Their effort has two major focuses: community-relations programs that anticipate problems and ease tensions between the utility and local residents and business owners, and new technologies that drastically limit the amount of excavation that needs to be done in repairing or replacing gas distribution lines. The paper describes a case study in the community-relations side of the equation which involved a recent project by Pacific Gas and Electric Co. (PG and E) in the congested streets of San Francisco`s famed Chinatown.

  7. Observations of the urban land surface energy balance in a Phoenix, AZ, residential suburb

    NASA Astrophysics Data System (ADS)

    Chow, W. T.; Volo, T. J.; Vivoni, E. R.; Jenerette, D.; Ruddell, B. L.

    2012-12-01

    Direct measurements of the surface energy balance (SEB) in urban areas through micro-meteorological observation platforms are relatively uncommon, but these observations are critical for a scientific understanding the connections between urban anthropogenic activity and the Earth's local and global climate. Observations of the SEB may be applied to assess the accuracy of urban canopy models and to understand urban climate phenomena, such as the heat island and its human health, energy, and water impacts. We present initial results of local-scale (~1 km2) eddy covariance observations taken from a 23 meter tall micro-meteorological eddy-covariance flux tower sited within a typical residential suburb located in the hot semiarid city of Phoenix, Arizona. Diurnal ensemble patterns of SEB for summer (MJJ) and winter (DJF) are presented, with consideration for synoptic and regional weather conditions (e.g. cloud/non-cloud conditions, as well as the onset of the North American Monsoon), as well as several descriptive statistics (e.g. mean and variability of each flux, as well as the relative partitioning of each flux over time). Comparisons with SEB fluxes measured in other cities of similar climates will also be discussed, along with the implications of these new observations for urban climate science.

  8. Big City Education: Its Challenge to Governance.

    ERIC Educational Resources Information Center

    Haskew, Laurence D.

    This chapter traces the migration from farms to cities and the later movement from cities to suburbs and discusses the impact of the resulting big city environment on the governance of big city education. The author (1) suggests how local, State, and Federal governments can improve big city education; (2) discusses ways of planning for the future…

  9. Kid-Friendly Cities Report Card, 2001.

    ERIC Educational Resources Information Center

    Polansky, Lee S., Ed.

    2001-01-01

    This report examines the health and wellbeing of children in the United States' largest cities, covering every city with a population of 100,000 or more, as well as the largest cities in states without any cities of this size. Research shows that many cities are becoming more child-friendly, with better access to good education, jobs, and health…

  10. Smart cities of the future

    NASA Astrophysics Data System (ADS)

    Batty, M.; Axhausen, K. W.; Giannotti, F.; Pozdnoukhov, A.; Bazzani, A.; Wachowicz, M.; Ouzounis, G.; Portugali, Y.

    2012-11-01

    Here we sketch the rudiments of what constitutes a smart city which we define as a city in which ICT is merged with traditional infrastructures, coordinated and integrated using new digital technologies. We first sketch our vision defining seven goals which concern: developing a new understanding of urban problems; effective and feasible ways to coordinate urban technologies; models and methods for using urban data across spatial and temporal scales; developing new technologies for communication and dissemination; developing new forms of urban governance and organisation; defining critical problems relating to cities, transport, and energy; and identifying risk, uncertainty, and hazards in the smart city. To this, we add six research challenges: to relate the infrastructure of smart cities to their operational functioning and planning through management, control and optimisation; to explore the notion of the city as a laboratory for innovation; to provide portfolios of urban simulation which inform future designs; to develop technologies that ensure equity, fairness and realise a better quality of city life; to develop technologies that ensure informed participation and create shared knowledge for democratic city governance; and to ensure greater and more effective mobility and access to opportunities for urban populations. We begin by defining the state of the art, explaining the science of smart cities. We define six scenarios based on new cities badging themselves as smart, older cities regenerating themselves as smart, the development of science parks, tech cities, and technopoles focused on high technologies, the development of urban services using contemporary ICT, the use of ICT to develop new urban intelligence functions, and the development of online and mobile forms of participation. Seven project areas are then proposed: Integrated Databases for the Smart City, Sensing, Networking and the Impact of New Social Media, Modelling Network Performance

  11. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This simulated natural color image presents a late spring view of north central Utah that includes all of the Olympic sites. The image extends from Ogden in the north, to Provo in the south; and includes the snow-capped Wasatch Mountains and the eastern part of the Great Salt Lake.

    This image was acquired on May 28, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution

  12. Social Planning for Small Cities.

    ERIC Educational Resources Information Center

    Meyers, James

    Derived mainly from publications by the League of California Cities, this guide to social planning for small cities presents the following: (1) social planning definitions; (2) a checklist of social planning concerns (provision for: adequate income and economic opportunity; optimal environmental conditions for basic material needs; optimal health…

  13. New York City: Musically Speaking.

    ERIC Educational Resources Information Center

    Aiex, Nola Kortner

    New York City as a subject has fascinated generations of artists, writers, and musicians. However, the glamorous image of the city has changed over the years, and in the 1960s, popular music, in particular, began to reflect a utopia/dystopia dichotomy in relation to New York. During the past twenty years, six popular singer-songwriters who have…

  14. Chicago, Illinois: The Windy City

    ERIC Educational Resources Information Center

    McIntosh, Phyllis

    2008-01-01

    Once famous mainly for stockyards and steel mills, Chicago now boasts more top-rated five-star restaurants than any other city in the United States and has been voted by various publications as one of the "Top 10 U.S. Destinations," one of the "Best Walking Cities" in the United States, and one of the "Ten Best Places to…

  15. Educating cities in Latin America

    NASA Astrophysics Data System (ADS)

    Messina, Graciela; Valdés-Cotera, Raúl

    2013-09-01

    This article considers the development of educating cities from a political perspective, illustrating in detail the diversity of organisations and individuals involved and the challenges they are facing. Bearing in mind that educating cities were established from the 1990s onwards in Europe and spread to other continents from there, the purpose of this article is to demonstrate how this proposal was adopted in Latin America. After discussing the basic aims of educating cities, the paper focuses on the Latin American experience, giving examples of existing projects within the educating cities initiative. The authors are particularly interested in the contrast between the political intentions of educating cities on the one hand and the social, economic, political and cultural world on the other hand. They observe that in this context there is a danger of the individual being forgotten, which contradicts the actual intention of the educating city concept. They also discuss the problem of who should carry out the realisation of educating cities and how the various stakeholders might coordinate their actions. Contemplating new directions at the end of their paper, the authors sum up a number of guidelines and offer recommendations for action in developing educating cities.

  16. Broken Cities: Liberalism's Urban Legacy.

    ERIC Educational Resources Information Center

    Hayward, Steven

    1998-01-01

    Argues how the nation's inner-city population exodus and economic decay is a result of modern liberal social policy. Three failures of liberalism regarding inner cities are examined: the failure to nurture the sources of economic growth; the failure to understand urban neighborhoods; and the failure to appreciate the importance of a strong moral…

  17. The Future of American Cities.

    ERIC Educational Resources Information Center

    Mulhern, John J., Ed.

    This document contains the proceedings of a conference dealing with the issues that face U.S. cities today. Convened in October of 1979, the conference was sponsored by the Federal Reserve Bank of Philadelphia. The document contains addresses and comments by six authorities on the current fiscal situation of large cities. The presentation…

  18. Knowledge Infrastructures for Solar Cities

    ERIC Educational Resources Information Center

    Vanderburg, Willem H.

    2006-01-01

    The evolution of contemporary cities into solar cities will be affected by the decisions of countless specialists according to an established intellectual and professional division of labor. These specialists belong to groups responsible for advancing and applying a body of knowledge, and jointly, these bodies of knowledge make up a knowledge…

  19. Educating Cities in Latin America

    ERIC Educational Resources Information Center

    Messina, Graciela; Valdés-Cotera, Raúl

    2013-01-01

    This article considers the development of educating cities from a political perspective, illustrating in detail the diversity of organisations and individuals involved and the challenges they are facing. Bearing in mind that educating cities were established from the 1990s onwards in Europe and spread to other continents from there, the purpose of…

  20. City Planning Unit: Grade 6.

    ERIC Educational Resources Information Center

    Dalton, William Edward

    Described is a project designed to make government lessons and economics more appealing to sixth-grade students by having them set up and run a model city. General preparation procedures and set-up of the project, specific lesson plans, additional activities, and project evaluation are examined. An actual 3-dimensional model city was set up on…