Alfalfa Pollination in Arizona: A Progress Report

This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]

Size and surface area dependent toxicity of silver nanoparticles in zebrafish embryos (Danio rerio)

Many studies addressing the toxicity of silver nanomaterials have found that smaller sized silver nanoparticles are usually more toxic to organisms and in cell culture than particles of larger sizes yet it is not entirely clear why. We investigated the size dependent toxicity of silver nanoparticles by measuring the response of embryonic zebrafish (Danio rerio) following exposure to a library of thirteen distinct silver nanoparticle size distributions with mean diameters between 8.9 nm and 112.6 nm. Data analysis using dose‐response modeling revealed that silver nanoparticles (AgNP) induced embryo toxicity that is dependent on the total surface area and not on the mass or particle number in solution. Included in this study is a comparison between embryo toxicity induced by silver nitrate (AgNO₃) and AgNPs for cardiovascular endpoints, as well as an investigation into the influence of the chorion on AgNP toxicity. This study demonstrates the importance of using alternative dose metrics in nanotoxicology, and highlights the value of using the embryonic zebrafish to explore nanomaterial structure activity relationships

An enhanced CRISPR repressor for targeted mammalian gene regulation.

The RNA-guided endonuclease Cas9 can be converted into a programmable transcriptional repressor, but inefficiencies in target-gene silencing have limited its utility. Here we describe an improved Cas9 repressor based on the C-terminal fusion of a rationally designed bipartite repressor domain, KRAB-MeCP2, to nuclease-dead Cas9. We demonstrate the system's superiority in silencing coding and noncoding genes, simultaneously repressing a series of target genes, improving the results of single and dual guide RNA library screens, and enabling new architectures of synthetic genetic circuits

Stability of citrate-capped silver nanoparticles in exposure media and their effects on the development of embryonic zebrafish (Danio rerio)

The stability of citrate-capped silver nanoparticles (AgNPs) and the embryonic developmental toxicity were evaluated in the fish test water. Serious aggregation of AgNPs was observed in undiluted fish water (DM-100) in which high concentration of ionic salts exist. However, AgNPs were found to be stable for 7 days in DM-10, prepared by diluting the original fish water (DM-100) with deionized water to 10%. The normal physiology of zebrafish embryos were evaluated in DM-10 to see if DM-10 can be used as a control vehicle for the embryonic fish toxicity test. As results, DM-10 without AgNPs did not induce any significant adverse effects on embryonic development of zebrafish determined by mortality, hatching, malformations and heart rate. When embryonic toxicity of AgNPs was tested in both DM-10 and in DM-100, AgNPs showed higher toxicity in DM-10 than in DM-100. This means that the big-sized aggregates of AgNPs were low toxic compared to the nano-sized AgNPs. AgNPs induced delayed hatching, decreased heart rate, pericardial edema, and embryo death. Accumulation of AgNPs in the embryo bodies was also observed. Based on this study, citrate-capped AgNPs are not aggregated in DM-10 and it can be used as a control vehicle in the toxicity test of fish embryonic development.Keywords: Nanoparticle Exposure Media, Nanoparticle Stability, Embryonic Zebrafish Toxicity, Silver Nanoparticle

Campus Vol IX N 4

Howard Studio. Cover. Picture. 1. Anonymous. Untitled. Prose. 4. Cook, Mike. misty Mood . Prose. 5. McIntosh, Bruce. Misty Mood . Picture. 5. Pritchard, Joen. In the Good \u27Ole Summertime... . Prose. 6. Stout, Prentice. In the Good \u27Ole Summertime... . Picture. 6. Hodges, John. How to Choose a Roommate . Prose. 7. Tuttle, C. Untitled. Cartoon. 7. Fenberg, Geo. M. Students--- . Prose. 3. Wood and Knapp. Jokes From the Jazz Age as Flips From Flappers . Prose. 8. Greenlee, Midge. Nine to Five . Prose. 10. Anonymous. Mr. and Miss Campus-1954 . Picture. 11. Anonymous. Well Shut My Mouth! . Prose. 14. Tuttle, C. Untitled. Cartoon. 14.; Miller, John. The Drums of Ku . Poem. 14. Hodge, Beth. About Face . Picture. 15. Rasor, Tip. Sports Calendar . Prose. 16. Anonymous. Senior Will . Prose. 18. Kull, Shaw. Untitled. Cartoon. 23

Gas buildup in Lake Nyos, Cameroon: The recharge process and its consequences

The gases dissolved in Lake Nyos, Cameroon, were quantified recently (December 1989 and September 1990) by two independent techniques: in-situ measurements using a newly designed probe and laboratory analyses of samples collected in pre-evacuated stainless steel cylinders. The highest concentrations of CO2 and CH4 were 0.30 mol/kg and 1.7 mmol/kg, respectively, measured in cylinders collected 1 m above lake bottom. Probe measurements of in-situ gas pressure at three different stations showed that horizontal variations in total dissolved gas were negligible. Total dissolved-gas pressure near the lake bottom is 1.06 MPa (10.5 atm), 50% as high as the hydrostatic pressure of 2.1 MPa (21 atm). Comparing the CO2 profile constructed from the 1990 data to one obtained in May 1987 shows that CO2 concentrations have increased at depths to below 150 m. Based on these profiles, the average rate of CO2 input to bottom waters was 2.6 x 108 mol/a. Increased deep-water temperatures require an average heat flow of 0.32 MW into the hypolimnion over the same time period. The transport rates of CO2, heat, and major ions into the hypolimnion suggest that a low-temperature reservoir of free CO2 exists a short distance below lake bottom and that convective cycling of lake water through the sediments is involved in transporting the CO2 into the lake from the underlying diatreme. Increased CH4 concentrations at all depths below the oxycline and a high 14C content (41% modern) in the CH4 4 m above lake bottom show that much of the CH4 is biologically produced within the lake. The CH4 production rate may vary with time, but if the CO2 recharge rate remains constant, CO2 saturation of the entire hypolimnion below 50 m depth would require ~140 a, given present-day concentrations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30812/1/0000471.pd

Customs Law

This article summarizes important developments in 2014 in customs law, including U.S. judicial decisions, trade, legislative, administrative, and executive developments, as well as Canadian and European legal developments

Whitefield News

File includes: January 2016 Volume 3, Issue 7 February 2016 Volume 3, Issue 8 March 2016 Volume 3, Issue 9 April 2016 Volume 3, Issue 10 May 2016 Volume 3, Issue 11 June 2016 Volume 3, Issue 12 July 2016 Volume 4, Issue 1 August 2016 Volume 4, Issue 2 September 2016, Volume 4, Issue 3 October 2016, Volume 4, Issue 4 November 2016, Volume 4, Issue 5 December 2016, Volume 4, Issue