SUSY Contributions to RbR_b and Top Decay

I report on a systematic analysis of the MSSM parameter space to obtain the best SUSY solution to the $R_b$ anomaly within the constraint of top quark decay. Phenomenological implications for top decay and direct stop production at the Tevatron collider are discussed.Comment: Latex file (3 pages)+ 2 ps files containing figures. Invited talk at SUSY96, Maryland, May 199

UV-induced refractive index changes in germanosilicate fibres

Photo-induced guided index changes approaching at both 633nm and 1.55µm, measured using a simple interferometric technique, are reported in germanosilicate single-mode optical fibres exposed to 266nm from the side

Patterns of energy allocation during energetic scarcity; evolutionary insights from ultra-endurance events.

Exercise physiologists and evolutionary biologists share a research interest in determining patterns of energy allocation during times of acute or chronic energetic scarcity. Within sport and exercise science, this information has important implications for athlete health and performance. For evolutionary biologists, this would shed new light on our adaptive capabilities as a phenotypically plastic species. In recent years, evolutionary biologists have begun recruiting athletes as study participants and using contemporary sports as a model for studying evolution. This approach, known as human athletic palaeobiology, has identified ultra-endurance events as a valuable experimental model to investigate patterns of energy allocation during conditions of elevated energy demand, which are generally accompanied by an energy deficit. This energetic stress provokes detectable functional trade-offs in energy allocation between physiological processes. Early results from this modelsuggest thatlimited resources are preferentially allocated to processes which could be considered to confer the greatest immediate survival advantage (including immune and cognitive function). This aligns with evolutionary perspectives regarding energetic trade-offs during periods of acute and chronic energetic scarcity. Here, we discuss energy allocation patterns during periods of energetic stress as an area of shared interest between exercise physiology and evolutionary biology. We propose that, by addressing the ultimate "why" questions, namely why certain traits were selected for during the human evolutionary journey, an evolutionary perspective can complement the exercise physiology literature and provide a deeper insight of the reasons underpinning the body's physiological response to conditions of energetic stress

Gamow-Teller Strength Distribution for 37-Cl(p,n)37-Ar

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Asymptotic channels and gauge transformations of the time-dependent Dirac equation for extremely relativistic heavy-ion collisions

We discuss the two-center, time-dependent Dirac equation describing the dynamics of an electron during a peripheral, relativistic heavy-ion collision at extreme energies. We derive a factored form, which is exact in the high-energy limit, for the asymptotic channel solutions of the Dirac equation, and elucidate their close connection with gauge transformations which transform the dynamics into a representation in which the interaction between the electron and a distant ion is of short range. We describe the implications of this relationship for solving the time-dependent Dirac equation for extremely relativistic collisions.Comment: 12 pages, RevTeX, 2 figures, submitted to PR

Spin-charge separation in the single hole doped Mott antiferromagnet

The motion of a single hole in a Mott antiferromagnet is investigated based on the t-J model. An exact expression of the energy spectrum is obtained, in which the irreparable phase string effect [Phys. Rev. Lett. 77, 5102 (1996)] is explicitly present. By identifying the phase string effect with spin backflow, we point out that spin-charge separation must exist in such a system: the doped hole has to decay into a neutral spinon and a spinless holon, together with the phase string. We show that while the spinon remains coherent, the holon motion is deterred by the phase string, resulting in its localization in space. We calculate the electron spectral function which explains the line shape of the spectral function as well as the ``quasiparticle'' spectrum observed in angle-resolved photoemission experiments. Other analytic and numerical approaches are discussed based on the present framework.Comment: 16 pages, 9 figures; references updated; to appear in Phys. Rev.

The CD28-Transmembrane Domain Mediates Chimeric Antigen Receptor Heterodimerization With CD28.

Anti-CD19 chimeric antigen receptor (CD19-CAR)-engineered T cells are approved therapeutics for malignancies. The impact of the hinge domain (HD) and the transmembrane domain (TMD) between the extracellular antigen-targeting CARs and the intracellular signaling modalities of CARs has not been systemically studied. In this study, a series of 19-CARs differing only by their HD (CD8, CD28, or IgG <sub>4</sub> ) and TMD (CD8 or CD28) was generated. CARs containing a CD28-TMD, but not a CD8-TMD, formed heterodimers with the endogenous CD28 in human T cells, as shown by co-immunoprecipitation and CAR-dependent proliferation of anti-CD28 stimulation. This dimerization was dependent on polar amino acids in the CD28-TMD and was more efficient with CARs containing CD28 or CD8 HD than IgG <sub>4</sub> -HD. The CD28-CAR heterodimers did not respond to CD80 and CD86 stimulation but had a significantly reduced CD28 cell-surface expression. These data unveiled a fundamental difference between CD28-TMD and CD8-TMD and indicated that CD28-TMD can modulate CAR T-cell activities by engaging endogenous partners

Field on Poincare group and quantum description of orientable objects

We propose an approach to the quantum-mechanical description of relativistic orientable objects. It generalizes Wigner's ideas concerning the treatment of nonrelativistic orientable objects (in particular, a nonrelativistic rotator) with the help of two reference frames (space-fixed and body-fixed). A technical realization of this generalization (for instance, in 3+1 dimensions) amounts to introducing wave functions that depend on elements of the Poincare group $G$. A complete set of transformations that test the symmetries of an orientable object and of the embedding space belongs to the group $\Pi =G\times G$. All such transformations can be studied by considering a generalized regular representation of $G$ in the space of scalar functions on the group, $f(x,z)$, that depend on the Minkowski space points $x\in G/Spin(3,1)$ as well as on the orientation variables given by the elements $z$ of a matrix $Z\in Spin(3,1)$. In particular, the field $f(x,z)$ is a generating function of usual spin-tensor multicomponent fields. In the theory under consideration, there are four different types of spinors, and an orientable object is characterized by ten quantum numbers. We study the corresponding relativistic wave equations and their symmetry properties.Comment: 46 page

A Comparison of 37-Ca(p,n) Cross Sections to 37-Ca β-Decay

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Development and evaluation of ofloxacin orally disintegrating tablets

Bitter taste of ofloxacin, a broad spectrum bactericidal agent, is masked and orally disintegrating tablets were formulated. The bitter taste is masked by forming complex between drug and weak cation exchange resins, Tulsion 335 and Indion 204. Effect of pH and drug:resin ratio on the drug loading was studied. Maximum drug loading was observed at pH 6. Ratio of 1:2 of drug:resin masked almost complete bitterness of ofloxacin. Formation of complexes was confirmed by IR spectroscopy. Physical characterization of taste masked complexes was carried out. Present work envisages the taste masking of ofloxacin and development of orally disintegrating tablets. The effect of pH and resin quantities on drug loading were studied to find the optimum conditions of drug loading for complete taste masking. Effect of superdisintegrants like sodium starch glycolate, croscarmellose sodium and polyplasdone XL at varying level on physical parameters of compressed tablets was also assessed. The formulations containing 5 % w/w polyplasdone XL showed about 90 % of drug release within 5 minutes. No significant differences were observed in the physical parameters of resinates as well as tablets prepared from Tulsion 335 and Indion 204.O gosto amargo de ofloxacina, agente bactericida de largo espectro, é mascarado e formularam-se comprimidos dispersíveis. O sabor amargo é mascarado pela formação de complexo entre o fármaco e resinas de troca catiônica fraca, Tulsion 335 e Indion 204. Efeito do pH e da proporção fármaco: resina sobre a carga de fármaco foi estudada. Carga de fármaco máxima foi observada em pH 6. Proporção 1:2 do fármaco: resina mascarou quase completamente o gosto amargo de ofloxacina. A formação de complexos foi confirmada por espectroscopia no IV. Caracterização física dos complexos de sabor mascarado foi realizada. O presente trabalho preconiza o mascaramento do gosto de ofloxacina e desenvolvimento decomprimidos por via oral, se desintegrando. O efeito do pH e da resina quantidades de carga de fármaco foram estudadas paraencontrar as condições óptimas de carga de fármaco para dissimulação do saborcompleto. Efeito da superdisintegrants como amido glicolato de sódio, croscarmelose sódica e Polyplasdone XL em diferentes níveis de parâmetros físicos de comprimidos também avaliados foi avaliada. As formulações contendo 5 %w/w Polyplasdone XL mostraram cerca de 90% de libertação do fármaco no prazo de 5 minutos. Não foram observadas diferenças significativas nos parâmetros físicos de resinatosbem como comprimidos preparados a partir de Tulsion 335 e Indion 204