Assessing the Genetic Status and Factors Leading to the Decline of the Roanoke Bass (Ambloplites Cavifrons)

Although numerous factors have led to the staggering declines in freshwater biodiversity throughout the United States and the world, habitat alteration and introduced species pose some of the greatest challenges to conservation efforts. Learning more about how these two factors lead to the decline of an endemic organism could help prevent the future loss of unique species and the premature conclusion of evolutionary trajectories. Roanoke bass (Ambloplites cavifrons) is a sport fish endemic to portions of the Roanoke, Chowan, Tar, and Neuse river basins of North Carolina and Virginia. This species has been in decline for many years, and it is believed that their continued existence is threatened by competition, and potentially hybridization and introgression with their introduced relative, the rock bass (Ambloplites rupestris). In addition to interactions with this invasive species, significant alteration of habitat is likely also a contributing factor in the decline of A. cavifrons. This study seeks to evaluate the relative contributions of these various factors to the decline of A. cavifrons. I utilized a combination of nuclear markers and mitochondrial sequence data to address the question of whether or not the two species are hybridizing in areas of syntopy, and furthermore to determine whether hybrids are fertile and able to breed back with the parental species. In addition, I identified extant populations of A. cavifrons throughout their historic range, and evaluated the genetic diversity of these populations and correlated these values with changes to the landscape in the form of alterations to watershed land use and the construction of impoundments. My results indicate large portions of the historic range of A. cavifrons no longer contain the species, and that remaining populations occur at the stream level and exist in isolation from one another. Obtaining this information allows for a better understanding of the current state of this unique species, provides information that may help managers prevent its disappearance from its native range, and affords insight into the interactions of an introduced and a native species in a landscape that has been heavily altered by human activity

OPIOID ADDICTION AND PREGNANCY: POTENTIAL EFFECTS OF SUBSTITUTION THERAPIES ON DEVELOPMENTAL MYELINATION

While most cells of the central nervous system (CNS) express opioid receptors, the role of the endogenous opioid system in CNS development remains poorly understood. Identification of opioid functions during brain maturation is particularly crucial in light of the increasing trend in opioid abuse and the use of opioid drugs during pregnancy. New substitution therapies in pregnant opioid addicts include buprenorphine, a mu opioid receptor partial agonist and kappa opioid receptor antagonist. However, while clinical studies demonstrated buprenorphine efficacy in reducing neonatal withdrawal symptoms, there is a lack of information on the potential effects of this drug on brain development. Previous work from our laboratory has shown that perinatal exposure to buprenorphine induces dose-dependent alterations in rat brain myelination. These time-specific effects suggested that both therapeutic and supra- therapeutic doses of the drug could alter the normal pattern of oligodendrocyte development. In support of this hypothesis, this thesis work has now found that buprenorphine exerts direct actions on the oligodendrocytes that are highly dependent on both the drug dose and stage of cell differentiation. When exposed to buprenorphine, oligodendrocyte progenitors isolated from 3-day-old rat brain exhibit increased cell proliferation. In contrast, treatment of more mature oligodendrocytes obtained from 9-day-old rat brain induces dramatic dose- specific effects on cell process network extension and membrane outgrowth. These later effects are accompanied by significant parallel changes in the expression of the four major splicing isoforms of myelin basic protein (MBP), a critical component of the myelin membrane and mature myelinating oligodendrocytes. Furthermore, similar dose-specific effects on MBP expression are also elicited by methadone, a mu opioid receptor agonist already approved for the treatment of pregnant opioid addicts. Experiments with CTOP, a highly selective antagonist of the mu opioid receptor, further contribute to the idea that this receptor subtype plays an important function in controlling oligodendrocyte maturation. These findings underscore the potential effects of opioid exposure during brain maturation and further indicate an important regulatory role of the endogenous opioid system in the control of oligodendrocyte development and myelination

An NMR crystallographic approach to monitoring cation substitution in the aluminophosphate STA-2

The authors thank the Leverhulme Trust (F/00 268/BJ), EPSRC (EP/E041825/1, EP/J501542/1, and EP/F018096/1) and the European Commission FP6 Marie Curie Research Training Network “INDENS” (MRTN-CT-2004–005503), and the Leverhulme Trust (F/00 268/BJ) for support. Accepted 23rd October 2014.The substitution of the divalent cations Mg2+ and Zn2+ into the aluminophosphate (AlPO) framework of STA-2 has been studied using an “NMR crystallographic” approach, combining multinuclear solid-state NMR spectroscopy, X-ray diffraction and first-principles calculations. Although the AlPO framework itself is inherently neutral, the positive charge of the organocation template in an as-made material is usually balanced either by the coordination to the framework of anions from the synthesis solution, such as OH− or F−, and/or by the substitution of aliovalent cations. However, the exact position and distribution of the substituted cations can be difficult to determine, but can have a significant impact upon the catalytic properties a material exhibits once calcined. For as-made Mg substituted STA-2, the positive charge of the organocation template is balanced by the substitution of Mg2+ for Al3+ and, where required, by hydroxide anions coordinated to the framework. [27] Al MAS NMR spectra show that Al is present in both tetrahedral and five-fold coordination, with the latter dependent on the amount of substituted cations, and confirms the bridging nature of the hydroxyl groups, while high-resolution MQMAS spectra are able to show that Mg appears to preferentially substitute on the Al1 site. This conclusion is also supported by first-principles calculations. The calculations also show that 31P chemical shifts depend not only on the topologically-distinct site in the SAT framework, but also on the number of next-nearest-neighbour Mg species, and the exact nature of the coordinated hydroxyls (whether the P atom forms part of a six-membered ring, P(OAl)2OH, where OH bridges between two Al atoms). The calculations demonstrate a strong correlation between the 31P isotropic chemical shift and the average bond angle. In contrast, for Zn substituted STA-2, both X-ray diffraction and NMR spectroscopy show less preference for substitution onto Al1 or Al2, with both appearing to be present, although that into Al1 appears slightly more favoured.PostprintPeer reviewe

Understanding the structure directing action of copper-polyamine complexes in the direct synthesis of Cu-SAPO-34 and Cu-SAPO-18 catalysts for the selective catalytic reduction of NO with NH3

This work has been supported by Johnson Matthey PLC, UK.Cu2+ cations complexed by linear polyamines have been studied as structure-directing agents (SDAs) for the direct synthesis of copper-containing microporous silicoaluminophosphate (SAPO) materials. The complexing ligands diethylenetriamine (DETA), N-(2-hydroxyethyl)ethylenediamine (HEEDA), triethylenetetramine (TETA), N,N′-bis(2-aminoethyl)-1,3-propanediamine (232), 1,2-bis(3-aminopropylamino)ethane (323), tetraethylenepentamine (TEPA) and pentaethylenehexamine (PEHA) have been investigated. For comparison, syntheses have been performed using the analogous nickel-polyamine complexes. Cu2+ and Ni2+ forms of both SAPO-18 and SAPO-34 materials have been prepared. While most polyamine complexes direct crystallisation to SAPO-34, SAPO-18 has been prepared with Cu2+(232), Ni2+(232) and Ni2+(TETA). The coordination geometry of the included metal complexes was studied by UV-visible and EPR spectroscopy and computer simulation. SAPO-18 is favoured by the smaller square planar complexes or octahedral species (with 2 water molecules) of 232 and TETA. Calcination leaves extra-framework Cu2+ and Ni2+ cations within SAPO-18 and SAPO-34 frameworks. In situ synchrotron IR spectroscopy of Ni-SAPO-18 has shown thermal template degradation occurs via nitrile intermediates. Rietveld structural analysis located extra-framework Cu2+ and Ni2+ cations released by calcination. In SAPO-34, Cu2+ and Ni2+ were located in the 8R window of the cha cage. A second site was found for Ni2+ at the centre of the six-membered rings (6Rs) of the double-six-ring (D6R) sub-units. In SAPO-18 both Cu2+ and Ni2+ cations were located only in the 6Rs of the D6R sub-units. Selected copper SAPO-18 and SAPO-34 samples were tested in the selective catalytic reduction of NO with ammonia (NH3-SCR); both showed high activity.PostprintPostprintPeer reviewe

In situ Synchrotron IR Microspectroscopy of CO2 Adsorption on Single Crystals of the Functionalized MOF Sc-2(BDC-NH2)(3)

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Cement-in-cement stem revision for Vancouver type B periprosthetic femoral fractures after total hip arthroplasty: A 3-year follow-up of 23 cases

Background and purpose Revision surgery for periprosthetic femoral fractures around an unstable cemented femoral stem traditionally requires removal of existing cement. We propose a new technique whereby a well-fixed cement mantle can be retained in cases with simple fractures that can be reduced anatomically when a cemented revision is planned. This technique is well established in femoral stem revision, but not in association with a fracture

Desiring Intersubjective Unity

(Statement of Responsibility) by Kristin Eschenroeder(Thesis) Thesis (B.A.) -- New College of Florida, 2008(Supplements) Accompanying materials: Includes 1 CD of Images.(Electronic Access) RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE(Bibliography) Includes bibliographical references.(Source of Description) This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.(Local) Faculty Sponsor: Anderson, Ki

Application of NMR crystallography to the determination of the mechanism of charge-balancing in organocation-templated AlPO STA-2

The combination of solid-state MAS NMR spectroscopy and first-principles calculations is used to elucidate the structure of an as-prepared microporous AlPO (STA-2), in which the organocation template (bis-diazabicyclooctane-butane) is charge balanced by hydroxyl groups coordinated to framework aluminium species. 27Al MAS NMR spectra show Al exists in both tetrahedral and five-fold coordination, with the latter directly coordinated to hydroxyl O atoms as well as framework O atoms. The relative intensities of these resonances can be used to determine that the hydroxyls bridge between the two types of Al. Calculation of NMR parameters using a periodic density functional theory approach are able to suggest assignments for the resonances in both 27Al and 31P NMR spectra. 31P chemical shifts are shown to depend not only on the topologically-distinct sites in the SAT framework but also on whether or not the P atoms form part of a six-membered P(OAl)2OH ring, where OH is a bridging hydroxyl. By diffraction six possible sites for the charge-balancing hydroxyls have been identified, but all are refined with an average occupancy of 0.33. However, predicted peak positions in two-dimensional J-HETCOR NMR spectra indicate that only one hydroxyl is found in each cancrinite cage, and suggest that the most likely arrangements are those that avoid the close approach of bridging hydroxyl groups in adjacent cages. We show that the use of a combination of NMR spectroscopy and calculation to elucidate structure, often referred to as “NMR Crystallography”, offers a promising route for the future study of as-made and substituted microporous materials.Publisher PDFPeer reviewe