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The Reactivity Patterns of Low-Coordinate Iron-Hydride Complexes

Description: This article discusses the reactivity patterns of low-coordinate iron-hydride complexes. The authors report a survey of the reactivity of the first isolable iron-hydride complexes with a coordiination number less than 5.
Date: April 30, 2008
Creator: Yu, Ying; Sadique, Azwana R.; Smith, Jeremy M.; Dugan, Thomas R.; Cowley, Ryan E.; Brennessel, William W. et al.
Partner: UNT College of Arts and Sciences

Making a Difference

Description: Lesson plan containing a collection of activities and resources regarding making a difference and that meet state education standards and national sustainability standards for the 4th grade level.
Date: August 29, 2014
Creator: Parsons, John
Partner: UNT Office of Sustainability

Mechanisms of Cyanide Assimilation in Pseudomonas fluorescens NCIMB 11764

Description: Pseudomonas fluorescens NCIMB 11764 was capable of utilizing cyanide as a sole nitrogen source for growth. Cyanate (OCN") and S-cyanoalanine could also serve as nitrogenous substrates, but do not appear to play a role as intermediates in cyanide metabolism. Growth of this strain on cyanate as the sole nitrogen source led to the induction of an enzyme characterized as a cyanase (EC 3.5.5.3) based on its stoichiometric conversion of cyanate to ammonia, and dependence on bicarbonate for maximal activity. However, since cyanase activity was not elevated in cyanide-grown cells it was concluded that it serves no role in cyanide metabolism. Related studies aimed at examining a possible role for S-cyanoalanine as a cyanide-assimilation intermediate showed that while this compound also serves as a nitrogen source, it also is not important in cyanide metabolism. Studies focused on the utilization of free cyanide as a growth substrate led to the development of a fed-batch cultivation procedure greatly facilitating further experimentation aimed at the identification of cyanide metabolites. In addition to CO_2 and NH_3 as described earlier, two additional metabolites including formamide and formate were detected by using nC-NMR, HPLC, radioisotrapping methods and other analytical means. The formation of metabolites was shown to be induced after growth on cyanide with the relative product yields dependent on the availability of oxygen. These findings support earlier work in which an oxygen-dependent mechanism was proposed for the formation of C02 and NH3. However, at least two additional oxygen-independent pathways of cyanide conversion can be elaborated by this organism. One of these involves conversion to formate and ammonia while the other leads to the formation of formamide, which is not further degraded. Thus, growth on cyanide appears to occur by several mechanisms of chemical transformation presumably serving both detoxification and nutritional roles. Since two of these mechanisms ...
Date: August 1992
Creator: Nagappan, Olagappan
Partner: UNT Libraries

Kinetic and Thermochemical Studies of the Recombination Reaction Na + O₂ + N₂ from 590 to 1515 K by a Modified High-Temperature Photochemistry Technique

Description: Article on kinetic and thermochemical studies of the recombination reaction sodium + oxygen + nitrogen from 590 to 1515 K by a modified high-temperature photochemistry technique.
Date: September 1, 1989
Creator: Marshall, Paul & Narayan, A. S.
Partner: UNT College of Arts and Sciences

Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction

Description: The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.
Date: May 2011
Creator: Thompson, Kristopher Michael
Partner: UNT Libraries

Functional Assessment of the Medicago truncatula NIP/LATD Protein Demonstrates That It Is a High-Affinity Nitrate Transporter

Description: Article on the functional assessment of the Medicago truncatula NIP/LATD protein demonstrating that it is a high-affinity nitrate transporter.
Date: October 2012
Creator: Bagchi, Rammyani; Salehin, Mohammad; Adeyemo, O. Sarah; Salazar, Carolina; Shulaev, Vladimir; Sherrier, D. Janine et al.
Partner: UNT College of Arts and Sciences

Obligately Thermophilic Nitrogen-Fixation in Some Soil Bacteria

Description: In the work presented here, it is claimed that bacteria have been isolated which are capable of growth at high temperatures utilizing molecular nitrogen as their sole nitrogen source. Soil bacteria were isolated which grew at 55 C in nitrogen-free media. They were found to be obligatory thermophiles in nitrogen-free media and facultative thermophiles in media containing organically bound nitrogen.
Date: August 1971
Creator: Milam, Mary
Partner: UNT Libraries

Integrated Assessment of Hypoxia in the Northern Gulf of Mexico

Description: This document details the ecological and economic effects of low oxygen (hypoxic) conditions in the Gulf of Mexico. This condition is caused by deforestation, river channelization, and the overuse of nitrogen in agricultural fertilizer. This document summarizes scientific evidence for the causes of hypoxia, the negative impact on Gulf of Mexico fisheries, and long-term national strategies for managing and mitigating the problem.
Date: May 2000
Creator: National Science and Technology Council (U.S.). Committee on Environment and Natural Resources.
Partner: UNT Libraries

An Assessment of Coastal Hypoxia and Eutrophication in U.S. Waters

Description: This document is about hypoxia in aquatic ecosystems. Hypoxia is a depletion of oxygen caused by runoff, land cover change, and other factors associated with population growth and agriculture. The report discusses mitigation strategies and trends in managing this problem.
Date: November 2003
Creator: National Science and Technology Council (U.S.). Air Quality Research Subcommittee.
Partner: UNT Libraries

Clearing the Waters: A focus on water quality solutions

Description: This report discusses global water issues and offers a variety of proposals for countering the degradation of freshwater ecosystems for the benefit of public health and the environment.
Date: March 2010
Creator: Palanaippan, Meena; Gleick, Peter H.; Allen, Lucy; Cohen, Michael J.; Christian-Smith, Juliet; Smith, Courtney et al.
Partner: UNT Libraries

A Review of the Utilization of Fission Fragment Energy for the Fixation of Nitrogen

Description: Report issued by the Brookhaven National Laboratory discussing methods of nitrogen fixation, and their economic impacts. As stated in the introduction, "studies are described on circulating dust fuels, as well as fixed plated, porous bed, and other types of fuels as the basis for chemo-nuclear reactor designs, and the various fuel systems are compared on a technical and economic basis" (p. 3). This report includes tables, and illustrations.
Date: January 17, 1961
Creator: Steinberg, Meyer; Powell, J. R. & Green, Leon
Partner: UNT Libraries Government Documents Department

Barnyard manure.

Description: Describes the benefits of more economical management of organic farm resources, namely barnyard manure. Discusses the management and application of methods for using fertilizers on the farm.
Date: May 10, 1906
Creator: United States. Dept. of Agriculture.
Partner: UNT Libraries Government Documents Department

Nonpoint-Source Discharges in Pequea Creek Basin, Pennsylvania, 1977

Description: From abstract: The objective of this project was to assess the magnitudes and types of nonpoint discharges that affect the water quality of Pequea Creek. The project included the determination of (1) the total discharge of suspended sediment, nitrogen, and phosphorus from the basin; (2) intermittent storm and base-flow discharges from six subbasin sites of varying size, geology, and land use; (3) the difference in magnitudes of the discharges during base-flow periods and storms; and (4) which variables most affect the transport of these constituents.
Date: November 1979
Creator: Ward, Janice R. & Eckhardt, David A.
Partner: UNT Libraries Government Documents Department

General Hydrology and External Sources of Nutrients Affecting Pine Lake, King County, Washington

Description: Objectives: This report presents the findings of a study that was designed to determine (1) the general hydrologic conditions in the immediate vicinity of the lake, and (2) the loadings of inorganic nitrogen and phosphorus from selected external sources that affect the lake.
Date: 1983
Creator: Dion, N. P.; Sumioka, S. S. & Winter, T. C.
Partner: UNT Libraries Government Documents Department

Regional Analysis of the Effects of Land Use on Stream Water Quality, Methodology and Application in the Susquehana River Basin, Pennsylvania and New York

Description: This report presents "a framework is presented for compiling available data for assessing statistical relationships between water quality and several factors of climate, physiography and land use" and includes several maps and graphs.
Date: May 1978
Creator: Lystrom, David J.; Rinella, Frank A.; Rickert, David A. & Zimmermann, Lisa
Partner: UNT Libraries Government Documents Department