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.

The Louisiana coast is prone to power tropical storm systems, known as hurricanes, which commonly cause significant damage to the environment and financial infrastructure in coastal states, such as Louisiana. Using landsat data acquired from the USGS, determining land cover degradation from seasonal low-pressure storms that span different decades can be made possible. This GIS-based study also takes into account elevation models (DEMs) to provide an accurate portrayal of how coastal vegetation influences the impact of these storms, as well as how storm intensity influences the morphology of coastlines.

Hawaii’s most active volcano, Kilauea, poses many threats to the surrounding infrastructure of the Big Island. Surface deformation from eruptions and underground magma tunnels have produced a growing lava lake within the Eastern Rift Zone, located on the Southeast tip of the island, since 2018. Using remote sensing techniques and GIS, I will use recent data collected from Kilauea’s eruptions and Halema’uma’u lava lake to create a volcanic hazards map of the region. A volcanic hazards map gives us insight to where the safest place are to inhabit on the surface of the island.

There are many major geologic units that outcrop in various regions of the Dallas-Fort Worth metroplex. A major unit that will be discussed in the current study is the Eagleford Shale. Previous studies have generated geologic maps that illustrate where this unit crops-out within the study region. The goal of this study is to create a modern geologic hazard zonation map of the Dallas-Fort Worth metroplex focusing on areas where the Eagleford crops-out. On this map, I will include the spatial distribution of discovered Eagleford outcrop locations and will integrate photographs that illustrate the stratigraphy of this formations using GIS.
Subsequently, I will use the map to calculate the area of all Eagleford surficial deposits within the study region. This shale is a mudrock that is primarily made up of soft-sediments and clays and can pose a geological hazard where it reaches the surface due to shrinking and swelling. This can cause major foundation issues to infrastructure that is built on this unit. Therefore, this map can be used for the purpose of taking precautionary measures when planning the construction of new buildings and road networks within the Dallas-Fort Worth metroplex.

The Lower Cenomanian Maness Shale is an argillaceous mudrock that occurs between the Buda Limestone and Woodbine Sandstone in the East Texas Field, and was originally placed within the Washita Group based on its biostratigraphy. It regionally extends throughout the East Texas Basin in tandem with the overlying Woodbine Group and displays considerable thickness and facies variations. The Maness interval is significant because previous studies indicate that it may be a hydrocarbon source rock.
Although this mudrock has been studied for several decades, the sediment source of the Maness remains in question. Prior studies have indicated that the sediment comprising the Maness could have come from multiple sources, one of them being the southern side of the Sabine Uplift. In the current study, I will correlate well logs through the south side of the Sabine Uplift from Polk and Tyler counties through Rusk county. I will then generate an isopach map of the study area and will compare thickness trends to those shown on the composite isopach map constructed by English (2020). Lastly, I will examine a core from Tyler or Polk counties that could potentially reveal clastic sandstones occurring within the Maness. The findings will be used to test my hypothesis that the Maness Shale is sourced from the southern portion of the Sabine Uplift.

Hardness, defined as resistance to surface deformation, is an intrinsic property of all materials including sedimentary rocks. The variables responsible for a sedimentary rock’s hardness are not completely understood. By understanding which variables control hardness, we may gain a better understanding of related rock strength. Rock strength, defined as a rock’s resistance to plastic deformation under loading, is an important parameter for many industries such as mining, civil engineering, and hydrocarbon exploration.
Numerous tests such as triaxial tests or uniaxial tests are used to quantify rock strength, but are often expensive, time consuming, or require substantial investment in laboratory setup. To circumvent these issues, other devices have been employed to determine rock strength. For example, the Proceq Equotip Bambino micro-rebound hammer (Bambino) has been used for decades to test the hardness of materials such as concrete, steel, and ceramics. These hardness values have been used to determine material strength. Selected studies on rocks empirically correlate between Bambino-derived hardness value (called Leeb hardness) and uniaxial compressive strength (UCS). However, significant scatter in the data suggest that certain intrinsic (e.g., density, bulk mineralogy, etc.) or extrinsic factors (e.g., sample volume, surface the sample rests on) need to be considered for a better correlation.
In this study, I examined the relations between Leeb hardness and UCS values, while examining lithologic variations and other properties such as bulk mineralogy, water loss, volume, density, and effective porosity. I found that bulk mineralogy, density, effective porosity, and water content correlated with a sample’s mechanical hardness. Also, a sample’s UCS is related to its density, effective porosity, and mechanical hardness. Ultimately, these data validated previous studies and shed new insight on the controlling properties of a rock’s hardness and strength.