Owing to the increasing importance of manganese(II) complexes in the field of magnetic resonance imaging (MRI), large efforts have been devoted to find an appropriate ligand for Mn(II) ion encapsulation by providing balance between the seemingly contradictory requirements (i.e., thermodynamic stability and kinetic inertness vs low ligand denticity enabling water molecule(s) to be coordinated in its metal center). Among these ligands, a large number of pyridine or pyridol based open-chain and macrocyclic chelators have been investigated so far. As a next step in the development of these chelators, 15-pyN3O2Ph and its transition metal complexes were synthesized and characterized using established methods. The 15-pyN3O2Ph ligand incorporates both pyridine and ortho-phenylene units to decrease ligand flexibility. The thermodynamic properties, protonation and stability constants, were determined using pH-potentiometry; the solid-state structures of two protonation states of the free ligand and its manganese complex were obtained by single crystal X-ray diffractometry. The results show a seven-coordinate metal center with two water molecules in the first coordination sphere. The longitudinal relaxivity of [Mn(15-pyN3O2Ph)]2+ was found to be 5.16 mM−1 s−1 at 0.49 T (298 K). Furthermore, the r2p value of 11.72 mM−1 s−1 (0.49 T), which is doubled at 1.41 T field, suggests that design of this Mn(II) complex does achieve some characteristics required for contrast imaging. In addition, 17O NMR measurements were performed in order to access the microscopic parameters governing this key feature (e.g., water exchange rate). Finally, manganese complexes of ligands with analogous polyaza macrocyclic scaffold have been investigated as low molecular weight Mn(CAT) mimics. Here, we report the H2O2 disproportionation study of [Mn(15-pyN3O2Ph)]2+ to demonstrate the versatility of this platform as well.

Fmoc-protected and propargyl-containing thymine and Cbz-protected cytosine monomers were synthesized for possible use in the pre- or post-functionalization of PNA oligomers via click chemistry. The monomers should be suitable for incorporation in normal automated solid phase PNA synthesis. The synthesis is suitable for the preparation of gram-quantities of monomers and uses reductive amination as the key step.

Do edge effects influence wildlife distributions in a small game reserve in South Africa?
Lyall A. Blanché*1 and Victoria J. Bennett1
1Department of Environmental Science, Texas Christian University, Fort Worth, TX 76129 USA
Physical boundaries in the landscape can influence the abundance and distribution of species through edges effects, which are characterized as a behavioral response to features or boundaries, creating an area of avoidance known as edge habitat. The implication is a reduction in the amount of available habitat for an individual and/or its population. Studies have shown that anthropogenic features, such as roads and fences, can cause edge effects. Thus, should we be considering the consequences of anthropogenic edge effects when managing wildlife populations in game reserves? To address this, we used Global Positioning System point locations collected from 2004-2020 on cheetah, elephant, leopard, and lion in Amakhala Game Reserve, a 66 km2 fenced reserve in the Eastern Cape of South Africa. This reserve is bordered by a national highway and bisected by a public road. We used regression analysis to determine any relationship between the proportion of locations within 5 m increments and 1) the national highway, 2) public road, 3) boundary fence, 4) a river on the reserve, and 5) control sections of the reserve. Our analysis revealed a significant positive correlation between elephant locations and distance from the national highway, with elephants avoiding a 600 m wide section of the reserve next to the highway. Our study highlights the importance of identifying potential edge effects to better inform the management of small reserves.

Globally, floods are the most common natural disasters, imposing stress on communities through infrastructure damage, financial costs, public health, and environmental damage. Serving as a major threat to the city of Houston, Texas (TX), this metropolitan area has an extensive flooding history. This project aims to develop a flood risk map for the White Oak Bayou Watershed, found in the North-East region of Houston. Using existing literature, the flood risk susceptibility for this study is based on seven factors: elevation, slope, flow accumulation, hydrologic classifications of soil, land use, rainfall, and distance to river networks. Using methods from existing literature, each individual factor was classified into 5 risk levels, based on their characteristics that make an area more prone to flooding. By using the weighted overlay analysis tool, the individual factors were weighted based on their contribution to overall flooding. The results show majority of the watershed is classified as medium risk, including areas of high and low flooding vulnerability. The high risk areas surround the river networks and increase risk towards the watershed’s discharge point, located in close proximity to the downtown area of Houston.

Urbanization imposes threats to the quantity and quality of stormwater, driving communities to identify water management strategies that aid in sustainable development. As demand for urbanization increases, green infrastructure (GI) practices can be implemented as mitigation strategies, allowing for sustainable growth in communities with limited harm to water resources. This project will model the Village Creek (VC) watershed, a semi-urban watershed in north-central Texas, using the Soil Water Assessment Tool (SWAT) to estimate the effects of GI on water quantity and quality. Topographic, land cover, and soil data along with historical water quality and climate data drove the model, then GI designs influenced the transport of streamflow, bacteria, sediments, and nutrients. We expect the results to quantify changes in water quantity and quality from GI implementation and highlight the effectiveness of GI for the watershed. This research provides VCLA watershed managers and stakeholders information on environmentally sound and sustainable watershed protection planning.