Source: Dissertation Abstracts International, Volume: 40-07, Section: B, page: 3162. / Thesis (Ph.D.)--The Florida State University, 1979.

In order to study high-spin states in beta-stable and neutron-rich nuclei, in-beam gamma-ray spectroscopy was performed following triton-induced reactions on heavy nuclei. Initial studies on isotopically pure targets of ('208)Pb confirm that the dominate reaction for 10-16 MeV tritons is compound nucleus formation, followed by emission of two neutrons. The (t,2n) reaction was found to populate low-spin states as well as high-spin states, and to sufficiently align the high-spin states so that information on transition multipolarities can be obtained from gamma-ray angular distribution measurements. Preliminary experiments on ('232)Th show that for compound nuclei produced by triton bombardment of actinide targets, decay by neutron emission competes favorable with fission, so that conversion electron spectroscopy following (t,xn) reactions may be useful for studying actinide nuclei. / Triton bombardment of isotopically pure ('196)Pt and ('198)Pt targets was used to study ('197)Au and ('199)Au, produced by the (t,2n) reaction. Excitation function, pulsed beam, and gamma-gamma coincidence experiments were performed on both targets, and gamma-ray angular distributions were measured in ('199)Au. Level schemes constructed from this data show that the systematic trends observed in the lighter odd-mass gold nuclei continue in ('197)Au, but deviations in these trends occur in ('199)Au. A 6 (+OR-) 2 ns isomer seen in ('197)Au is believed to be a 2 1/2+, three particle state. The theory which best explains the results of these experiments is the cluster-vibration model, as only this model correctly predicts the large level density of negative-parity states found at excitation energies of 1-2 MeV. / Source: Dissertation Abstracts International, Volume: 43-03, Section: B, page: 0722. / Thesis (Ph.D.)--The Florida State University, 1982.

Two nuclear isomers were studied using in-beam gamma-ray spectroscopic techniques in conjunction with the reactions ('204)Hg(t,2n(gamma))('205)Tl and ('204)Hg(t,p(gamma))('206)Hg. The isomeric state in ('205)Tl was determined to have J('(pi)) = 25/2('+) with the major configuration (('206)Pb7('-) x h(,11/2)('-1)). The mean lifetime and gyromagnetic ratio for the state were determined to be (tau)(,m) = 3.7 (+OR-) 0.3 (mu)sec and g = 0.544 (+OR-) 0.008, respectively. Using this g-factor and previously measured g-factor for the ('206)Pb7('-) state, a g-factor, g = 1.264 (+OR-) 0.027, was deduced for an h(,11/2) proton state. For the nucleus ('206)Hg a new isomeric state was seen at 2.102 MeV excitation energy. This state was determined to have J('(pi)) = 5('-) with a mean lifetime (tau)(,m) = 3.1 (+OR-) 0.3 (mu)sec and the gyromagnetic ratio was measured to be 1.09 (+OR-) 0.01. The major configuration of the isomeric state if {h(,11/2)('-1)s(,1/2)('-1)} and using the value for g(h(,11/2)) determined from ('205)Tl, the g-factor for a 3s(,1/2) proton state was determined. / Source: Dissertation Abstracts International, Volume: 43-04, Section: B, page: 1098. / Thesis (Ph.D.)--The Florida State University, 1982.

The stability constants for trivalent Eu and Am complexes with a humic acid (extracted from sediment from Lake Bradford, near Tallahassee, Florida) were measured at trace level using a solvent extraction system. The organic extractant was di(2-ethylhexyl) phosphoric acid (HDEHP) in toluene; aqueous phases were humic acid solutions at a constant ionic strength of 0.1M (NaClO(,4)). / The humic acid carboxylate capacity (3.86 (+OR-) 0.03 meg/g) was determined by direct potentiometric titration. The humic acid displayed the typical characteristics of a polyelectrolyte--its apparent pK increased as the degree of ionization ((alpha)) increased. The Eu and Am stability constants also increased as (alpha) increased. / For Eu: log (beta)(,1) = 8.86(alpha) + 4.39; log (beta)(,2) = 3.55(alpha) + 11.06For Am: log (beta)(,1) = 9.32(alpha) + 3.83; log (beta)(,2) = 4.07(alpha) + 10.4 / Calculations show that with hydroxide, carbonate, and humate as competing ligands, under conditions present in natural waters, only the M(humate)(,1) complex is important for many trivalent lanthanides and actinides. / Humic acid precipitated to varying degrees when contacted with toluene in the solvent-extraction system. UV-visible absorption spectroscopy was used to monitor humic acid concentrations (GREATERTHEQ) 0.005 g/l. The radioactive mass balance of the solution phases is not constant due to the activity bound to the precipitated humic acid, therefore radioactivity in both phases must be assayed. / Solvent-extraction and cation-exchange resin systems were used to measure Pu-humate binding. Experiments were done with Pu(IV) and Pu(VI) at pCH('(TURN)) 3.7. Pu(VI) was never stable in the experiments, irrespective of the presence of humic acid. The stability constants for Pu(IV)-humate binding at (alpha) = 0.29 are estimated as log (beta)(,1) = 12.4 and log (beta)(,2) = 17.2. Because humic acid adsorbs to cation-exchange resin, the resin technique is not suitable for stability constant measurements, since it is not possible to monitor the radioactivity in the solid resin phase. / Source: Dissertation Abstracts International, Volume: 43-09, Section: B, page: 2901. / Thesis (Ph.D.)--The Florida State University, 1982.

Proton-electron, proton-gamma, and proton-gamma-gamma coincidence techniques have been used to study excited state transitions in even-even nuclei in the mass 100 region produced in the (t,p) reaction (E(,t) = 16 MeV). Using the (t,p) proton-gamma-gamma coincidence method, we have established five new levels in ('112)Pd and 3 new levels in ('102)Mo. Our discovery of a possible 10('+) level in ('102)Mo would be, if confirmed, the first physical evidence of a back-bending anomaly in the mass 100 region. Using the simultaneous proton-electron and proton-gamma coincidence methods, EO transitions in ('100)Mo, ('102)Mo, ('106)Ru, ('108)Pd, ('110)Pd, and ('112)Pd have been observed. Branching ratios for these EO transitions have been used to calculate the X(,ijk) and (rho)('2)(,ij) values for a number of transitions of the type O(,i)('+) - O(,f)('+) in these nuclei. / The results of our measurements are discussed in terms of current nuclear models. The back-bending anomaly at J('(pi)) = 10('+)in ('102)Mo confirms earlier theoretical predictions of such an anomaly. Level systematics in the Pd isotopes, particularly those of excited O('+) states, are in general agreement with the proton intruder orbital picture used to describe Cd nuclei. The systematics of monopole strengths in the Mo isotopes agree with the picture of a subshell proton intruder configuration. / Source: Dissertation Abstracts International, Volume: 47-06, Section: B, page: 2432. / Thesis (Ph.D.)--The Florida State University, 1986.

The question of intrinsic reflection asymmetry or stable-octupole deformation in ('227)Ac was studied by the single-proton stripping reactions ('226)Ra(('3)He,d)('227)Ac with E(,3He) = 30 MeV and ('226)Ra((alpha),t)('227)Ac with E(,(alpha)) = 30 MeV and by measuring the magnetic moment of the first excited 3/2('+) state at 27.38 keV by a differential perturbed angular correlation (DPAC) experiment. Theoretical differential cross sections were determined using calculated nuclear structure factors with and without octupole-deformed Woods-Saxon model wave functions. Theoretical values for the magnetic moments of the ground state and first excited state with and without octupole deformation were determined using calculated intrinsic g-factors from folded Yukawa model wave functions. / The results of the proton-stripping cross sections are inconclusive. Some of the levels populated in our studies agree with the stable-octupole model, some with the quadrupole model and the highest intensity level, the 13/2('+) level at 210.92 keV which is populated in both reactions, does not agree with either model. Therefore, further theoretical calculations are required before the question of stable octupole deformation in ('227)Ac can be answered by these single-proton stripping studies. However, we have confirmed several orbital energies predicted by decay scheme studies. Our investigation of the energy spacings of these orbitals shows that the inclusion of a stable octupole deformation in the ('227)Ac nuclear core is necessary even to give the correct order of these orbitals. / A comparison of our measured value for the magnetic moment of the first excited state with a previous measurement for the ground state seems to support stable octupole deformation in ('227)Ac. Therefore, the energy ordering of orbitals and the magnetic moment results are consistent and they seem to support a stable-octupole deformed shape for the ground state parity doublet in ('227)Ac. Furthermore, our results are consistent with the branching ratio determination of the magnetic moment of the first excited state in ('227)Ac which is in agreement with the stable-octupole model prediction. / Source: Dissertation Abstracts International, Volume: 47-03, Section: B, page: 1056. / Thesis (Ph.D.)--The Florida State University, 1986.

Source: Dissertation Abstracts International, Volume: 16-04, page: 0651. / Thesis (Ph.D.)--The Florida State University, 1956.

The nuclear spectroscopy of ('96)Nb and ('94)Nb was studied using the proton pickup (t, (alpha)) reaction on isotopically enriched targets of ('97)Mo and ('95)Mo. The experiments were performed at the tandem Van de Graff facilities of Los Alamos National Laboratory. The (alpha) particles were momentum analyzed in a quadrupole-dipole-dipole-dipole magnetic spectrometer to determine excitation energies of nuclear states. The experiments were performed at several angles and the resulting angular distributions were compared to distorted wave Born approximation calculations to determine angular momentum transfer values. The 3-member of the (pi)(p1/2)('1)(nu)(d5/2)('-1) doublet in ('96)Nb has been reassigned at 876 keV. The ten members of the (pi)(p3/2)('-1)(nu)(d5/2)('-1) and (pi)(f5/2)('-1)(nu)(d5/2)('-1) multiplets in ('96)Nb were identified for the first time. Additionally, several other new states in ('96)Nb are reported. Angular momentum transfer values were determined for twenty-six states in ('94)Nb. Fifty-four states were observed in ('94)Nb up to less than three MeV in excitation energy. Four of these states are previously unreported. / Source: Dissertation Abstracts International, Volume: 46-06, Section: B, page: 1917. / Thesis (Ph.D.)--The Florida State University, 1985.

Source: Dissertation Abstracts International, Volume: 30-05, Section: B, page: 2075. / Thesis (Ph.D.)--The Florida State University, 1969.

An often proposed mechanism to overcome the system of efflux transporters and tight junctions present at the blood brain barrier (BBB) is the receptor-mediated transport via endocytosis. Among the proposed transport vehicles, the transferrin receptor (TfR) has been considered to be one of the most attractive targets. Besides transferrin itself and the antibody OX26 (anti-rat TfR-antibody), it has recently been shown that peptides are also able to bind to the transferrin receptor and are internalized into TfR expressing cells. In this study we evaluated the ability of the 68Ga-labeled peptide THRPPMWSPVWP to become internalized into human TfR bearing cells to pre-evaluate its potential to act as a carrier system for small molecules across the BBB utilizing the TfR receptor located on the endothelial cells. To prove the validity of this concept we first synthesized the peptide THRPPMWSPVWP, and then a conjugate consisting of the D2 receptor ligand fallypride and the peptide which was synthesized by our collaborators and evaluated as to its binding affinity towards the D2 receptor. The conjugate still showed a high receptor affinity (Ki = 27 nM) despite the strong structural alteration exerted by the peptide. / For radioactive-labeling, the reported TfR-binding peptide THRPPMWSPVWP was derivatized with p-SCN-Bn-NOTA. It was then labelled with 68Ga by our collaborators. The uptake of the 68Ga-labelled peptide into TfR-bearing cells was investigated using two human TfR-expressing cell lines, the human glioblastoma cell line U87MG and the human colon adenocarcinoma cell line HT-29 to assess the peptides' potential as a carrier molecule targeting the TfR receptor . The binding was found to be less than 1% after 60 min incubation at 37°C. / These results suggest that the concept of using peptide THRPPMWSPVWP to act as a carrier system for short lived PET radio-pharmaceuticals across the BBB within a reasonable time span is doubtful. However, further experiments have to be carried out to determine the potential of this peptide as transferrin receptor targeting carrier molecule for therapeutic agents. / Besides, and owing to the need for optimization of the synthetic procedures for 18F labeling of biologically-active peptides for clinical PET, we also investigated the possibility to synthesize a glucose based labeling synthon 2,3,4-tri-O-acetyl-1-azido-6-[18F]fluoro-β-D-glucopyranoside, to radiolabel alkyne derivatized peptides with 18F using click chemistry. Our strategy would combine the advantages of carbohydration of peptides with the fast and efficient click reaction. We synthesized 2,3,4-tri-O-acetyl-1-azido-6-O-p-toluene sulfonyl-β-D- glucopyranoside in an overall chemical yield of 80%, which served as a labeling precursor bearing an azide group ready for coupling to an alkyne derivative of a biologically active peptide by click chemistry and a p-toluene sulfonyl group ready for radio-labeling with 18F by a nucleophilic substitution reaction. The second compound was 2,3,4-tri-O-acetyl-1-azido-6-fluoro-β-D-glucopyranoside in an overall chemical yield of 77%, which served as a reference compound to establish HPLC and TLC conditions for the radio-labeling experiments. Initial labeling experiments with nucleophilic 18F did not yield the desired 18F-labeled glucose derivative so far. We are currently taking efforts to radiolabel the precursor with 18F buy re-crystallizing the precursor several times as it was proven by HPLC that it still contains some impurities. These impurities can compromise the intended labeling reaction with 18F. / Un mécanisme proposé expliquant le transport par efflux présent dans la 'blood brain barrier' consiste en un système de transport membranaire assisté faisant intervenir des récepteurs spécifiques, par d'endocytose. Parmi les vésicules de transport proposées, les récepteurs de transferrine (TfR) sont considérés comme les plus attractives. A part la transferrine et l'anticorps pour clone MRC OX-26 (anticorps TfR anti-rat), il a été montré que des peptides sont aussi capables de se lier spécifiquement au récepteur de la transferrine, puis d'y être internalisé dans les cellules possédant les récepteurs à transferrine. Dans cette étude, nous avons évalué la possibilité du peptide 'THRPPMWSPVWP' marqué avec du 68G de s'internaliser dans des cellules humaines présentant les récepteurs TfR. Nous avons aussi évalué son potentiel de se comporter comme vecteur de transport de petites molécules à travers la 'blood brain barrier'. Nous avons utilisé des cellules endothéliales avec des récepteurs TfR. Pour prouver la validité du concept, nous avons synthétisé le peptide THRPPMWSPVWP, puis conjugué au fallypride de type D2, qui est un ligand avec une grande affinité pour les récepteurs du TfR. L'ensemble a été évalué par nos collaborateurs afin de vérifier l'affinité de liaison vis-à-vis des récepteurs du TfR. Ce conjugué à montré une grande affinité précités (Ki = 27 nM), malgré de fortes altérations au niveau de sa structure causées par la présence du peptide. Pour le marquage radioactif, le peptide THRPPMWSPVWP bioconjugué ci-dessus a été dérivé avec le p-SCN-Bn-NOTA et radio-marqué au 68Ga par nos collaborateurs. Les propriétés de ce peptide ont été étudiées en utilisant deux lignées cellulaires différentes présentant les récepteurs TfR, soit des cellules de type tumoral glial (U-87 MG) et des cellules carcinomes de côlon humain (HT-29), afin d'étudier le potentiel du peptide à se comporter comm / D'autre part, du fait de l'optimisation des procédures de synthèse pour le radio marquage au 18F de peptides biologiques actifs, dans le cadre d'études cliniques de 'PET', nous avons envisagé de synthétiser un nouveau synthon radio-marqué dérivant du glucose, le 2,3,4-tri-O-acetyl-1-azido-6-[18F]fluoro-β-D-glucopyranoside, pour radio-marquer des dérivés de type 'alkyne', par la technique de 'click chemistry'. Notre stratégie combine les avantages du processus de 'carbohydratation' des peptides et de la réaction de 'click chemistry'. Nous avons synthétisé le 2,3,4-tri-O-acetyl-1-azido-6-O- p-toluene sulfonyl β-D-glucopyranoside avec un rendement de 80%. Ce dernier possède un groupe p-toluène sulfonyle qui sert de précurseur pour radio-marquer la molécule au 18F par une réaction de substitution nucléophile, et présente également un groupement 'azide', permettant le couplage rapide avec un peptide actif possédant une fonction 'alkyne'. Le 2eme composé préparé est le 2,3,4-tri-O-acetyl-1-azido-6-fluoro-β-D-glucopyranoside, avec un rendement de 77%. Ce dernier servant de référence pour établir les conditions HPLC et par CCM nécessaires au radio-marquage. Les études préliminaires avec le 18F comme nucléophile n'ont pas conduit au composé de type 'glucose' radio-marqué au 18F. Nos efforts actuels se portent sur le radio-marquage du précurseur au 18F en recristallisant ce dernier. Il a été montré par HPLC que ce dernier contient des impuretés, qui empêcheraient le radio-marquage au 18F.