Induced Parity Violation in Odd Dimensions

One of the interesting features about field theories in odd dimensions is the induction of parity violating terms and well-defined {\em finite} topological actions via quantum loops if a fermion mass term is originally present and conversely. Aspects of this issue are illustrated for electrodynamics in 2+1 and 4+1 dimensions. (3 uuencoded Postscript Files are appended at the end of the TexFile.)Comment: 10 pages, UTAS-PHYS-94-0

Metabolism of Arachidonate-containing Phospholipid Molecular Species in the Murine Macrophage-like Cell Line, P388d1

Glycerophospholipids of mammalian cells exist as chemically diverse structures with various fatty acids at the sn-1 and sn-2 positions. Arachidonic acid, a polyunsaturated fatty acid, which may be converted to biologically active eicosanoids such as prostaglandins, thromboxanes, and leukotrienes, is found predominantly in the sn-2 position of glycerophospholipids. The purpose of this study was to examine, at the level of the individual molecular species, the incorporation of arachidonate into phospholipids and its release from phospholipids during stimulation. In this way, the specificity of the enzymes controlling arachidonate metabolism could be examined in order to clarify the processes that control the metabolism of this precursor of potent biological mediators. An investigation of the deacylation-reacylation mechanisms for the incorporation of arachidonic acid into the cellular phospholipids revealed that both the CoA-independent transacylation and CoA-dependent acylation mechanisms are active in the P388D1 macrophages. The CoA-independent transacylase preferentially acylated the alkyllysoglycero-phosphatidylcholine substrate with the polyunsaturates, arachidonate, and docosahexaenoate. The CoA-dependent pathways exhibited less selectively and acylated the alkyl-substrate with more saturated fatty acids. Supplementation of the P388D1 macrophages with the n-3 marine oil fatty acids, eicosapentaenoate and docosahexaenoate resulted in the enrichment of the cellular phospholipids with these polyunsaturates at the expense of arachidonate-containing molecular species. Using methodology, which permits the measure of both mass and specific radioactivity changes in the molecular species of phospholipids, it was determined that the arachidonate-containing species are preferentially degraded during stimulation with the calcium ionophore, A23187. Stimulation with calcium ionophore results in the activation of a calcium dependent phospholipase specific for the arachidonate-containing species. Together, these results demonstrate that the incorporation and release of arachidonic acid is regulated by enzymes that bear distinct substrate specificities. The specificities of these enzymes can be directly related to the trafficking of arachidonate and its various esterified forms in cell phospholipids

The NASA controls-structures interaction technology program

The interaction between a flexible spacecraft structure and its control system is commonly referred to as controls-structures interaction (CSI). The CSI technology program is developing the capability and confidence to integrate the structure and control system, so as to avoid interactions that cause problems and to exploit interactions to increase spacecraft capability. A NASA program has been initiated to advance CSI technology to a point where it can be used in spacecraft design for future missions. The CSI technology program is a multicenter program utilizing the resources of the NASA Langley Research Center (LaRC), the NASA Marshall Space Flight Center (MSFC), and the NASA Jet Propulsion Laboratory (JPL). The purpose is to describe the current activities, results to date, and future activities of the NASA CSI technology program

What is the Potential Impact of the IsoDAR Cyclotron on Radioisotope Production: A Review

The IsoDAR collaboration is developing a high-current cyclotron for a neutrino search experiment. Designed to deliver 10 mA of 60 MeV protons, the current and power of this cyclotron far exceed those of existing accelerators, opening new possibilities for the production of radiopharmaceutical isotopes, producing very high-activity samples in very short times. The cyclotron can also be easily configured to deliver ions other than protons including 1 mA of alpha particles at 240 MeV: this flexibility gives a broad reach into new areas of isotope production. We explain how IsoDAR overcomes the beam limits of commercial cyclotrons, and how it could represent the next step in isotope production rates.Comment: 23 pages, 7 figures, manuscript submitted to European Journal of Nuclear Medicin

Medical Isotope Production with the IsoDAR Cyclotron

Authors describe technical advances that will allow the IsoDAR cyclotron -- being developed for neutrino physics research -- to produce medical isotopes more efficiently than existing cyclotrons can.Comment: 3 pages 1 tabl

Gauge covariance and the fermion-photon vertex in three- and four- dimensional, massless quantum electrodynamics

In the quenched approximation, the gauge covariance properties of three vertex Ans\"{a}tze in the Schwinger-Dyson equation for the fermion self energy are analysed in three- and four- dimensional quantum electrodynamics. Based on the Cornwall-Jackiw-Tomboulis effective action, it is inferred that the spectral representation used for the vertex in the gauge technique cannot support dynamical chiral symmetry breaking. A criterion for establishing whether a given Ansatz can confer gauge covariance upon the Schwinger-Dyson equation is presented and the Curtis and Pennington Ansatz is shown to satisfy this constraint. We obtain an analytic solution of the Schwinger-Dyson equation for quenched, massless three-dimensional quantum electrodynamics for arbitrary values of the gauge parameter in the absence of dynamical chiral symmetry breaking.Comment: 17 pages, PHY-7143-TH-93, REVTE

Effect of undernutrition on testicular blood flow and metabolism and the output of testosterone in the

Summary. The food intake of six rams was restricted for 3 months, resulting in a reduction of body fat to less than 12% of live weight, compared with 25 to 49% in well-fed controls. At the end of this period of undernutrition, blood flow and the uptake of oxygen and glucose in unit weight of testis, when estimated during anaesthesia, were lower than in the controls, and testis weight was reduced. The fraction of oxygen uptake that could be accounted for by the oxidation of glucose was unchanged, although the respiratory quotient was slightly higher in the underfed rams. Oxygen uptake by homogenates and mitochondria from the testes of underfed rams was lower under most conditions of incubation applied. Testosterone output (mg/ram/day \m=+-\s.e.m.) was 0\m=.\4\m=+-\0\m=.\2in the underfed rams and 3\ m=. \ 5\ m=+-\ 0\ m=. \ 7 in well-fed controls; in six other well-fed rams, sampled while conscious, testosterone output was 2\m=.\8 \ m=+-\ 0\ m=. \ 3

Molecular evidence of Ureaplasma urealyticum and Ureaplasma parvum colonization in preterm infants during respiratory distress syndrome

BACKGROUND: Ureaplasma urealyticum and U. parvum have been associated with respiratory diseases in premature newborns, but their role in the pathogenesis of the respiratory distress syndrome (RDS) is unclear. The aim of this study was to detect, using molecular techniques, the role of Mycoplasma spp. and Ureaplasma spp. in respiratory secretion and blood specimens of preterm newborns with or without RDS and to evaluate the prevalence of perinatal U. urealyticum or U. parvum infection. The influence of chemotherapy on the clinical course was also evaluated. METHODS: Tracheal aspirate or nasopharingeal fluid samples from 50 preterm babies with (24) or without RDS (26) were analysed for detection of U. urealyticum and U. parvum by culture identification assay and PCR. Sequencing analysis of amplicons allowed us to verify the specificity of methods. Clarithromycin (10 mg kg(-1 )twice a day) was administered in ureaplasma-positive patients who presented clinical signs of RDS. RESULTS: 15/24 neonates with RDS (p < 0.001) and 4/26 without RDS were found PCR-positive for U. urealyticum or U. parvum. Culture identification assay was positive in 5/50 newborns, three of which with RDS. Sequencing analyses confirmed the specificity of these methods. Association of patent ductus arteriosus with ureaplasma colonization was more statistically significant (p = 0.0004) in patients with RDS than in those without RDS. CONCLUSION: Colonization of the lower respiratory tract by Ureaplasma spp. and particularly by U. parvum in preterm newborns was related to RDS. The routine use of molecular methods could be useful to screen candidate babies for etiologic therapy