Synthesis and Structures of Co Bis-Trifluoromethylpyrazolate Complexes

Reactions of Co(PMe3)(3)Cl or CoCl2 with 3,5-(CF3)(2)-PzNa in hexane give Co(PMe3)(3)(3,5-(CF3)(2)-Pz) (1) and Co(PMe3)(3)(3,5-(CF3)(2)-Pz)(2) (2) respectively (3,5-(CF3)(2)-PzNa = sodium bis-trifluoromethylpyrazolate). Reaction of (3,5-(CF3)(2)-PzH) with Co(PMe3)(4) produces the unusual complex [cis-Co(PMe3)(4)H-2][Co(PMe3)(3,5-( CF3)(2)-Pz)(3)] (3) which formally contains a [Co(III)](+)[Co(II)](-) complex ion pair. Reaction of 3,5-(CF3)(2)-PzLi with an oxygenated suspension of CoCl2 and 3 equivalents of PMe3 gives (3,5-(CF3)(2)-Pz)(2)Co(mu-3,5-(CF3)(2)Pz)(mu-OPMe3)Li(OPMe3)(2) (4), while 2 reacts with LiOH to give [(PMe3)Co(mu-3,5-(CF3)(2)-Pz)(2)(mu(3)-OH)Li](2) (5). Both 2 and 3 react with O-2 in toluene solution to give Co(OPMe3)(2)(3,5-(CF3)(2)-Pz)(2) (6). All compounds have been characterized spectroscopically and by single crystal X-ray diffraction studies.Welch Foundation F-816Petroleum Research Fund 47014-ACSNSF 0741973Chemistr

Notch activates Wnt-4 signalling to control medio-lateral patterning of the pronephros

Previous studies have highlighted a role for the Notch signalling pathway during pronephrogenesis in the amphibian Xenopus laevis, and in nephron development in the mammalian metanephros, yet a mechanism for this function remains elusive. Here, we further the understanding of how Notch signalling patterns the early X. laevis pronephros anlagen, a function that might be conserved in mammalian nephron segmentation. Our results indicate that early phase pronephric Notch signalling patterns the medio-lateral axis of the dorso-anterior pronephros anlagen, permitting the glomus and tubules to develop in isolation. We show that this novel function acts through the Notch effector gene hrt1 by upregulating expression of wnt4. Wnt-4 then patterns the proximal pronephric anlagen to establish the specific compartments that span the medio-lateral axis. We also identified pronephric expression of lunatic fringe and radical fringe that is temporally and spatially appropriate for a role in regulating Notch signalling in the dorso-anterior region of the pronephros anlagen. On the basis of these results, along with data from previous publications, we propose a mechanism by which the Notch signalling pathway regulates a Wnt-4 function that patterns the proximal pronephric anlagen

Design of a tunable, room temperature, continuous-wave terahertz source and detector using silicon waveguides

We describe the design of a silicon-based source for radiation in the 0.5-14 THz regime. This new class of devices will permit continuously tunable, milliwatt scale, cw, room temperature operation, a substantial advance over currently available technologies. Our silicon terahertz generator consists of a silicon waveguide for near-infrared radiation, contained within a metal waveguide for terahertz radiation. A nonlinear polymer cladding permits two near-infrared lasers to mix, and through difference-frequency generation produces terahertz output. The small dimensions of the design greatly increase the optical fields, enhancing the nonlinear effect. The design can also be used to detect terahertz radiation

Archaeological Survey of the Crystal City Municipal Landfill Extension, Zavala County, Texas

At the request of Ozuna and Associates, Inc., Consulting Engineers of San Antonio, Texas, an archaeological survey was conducted by the Center for Archaeological Research (CAR) for a proposed 40-acre extension to the Crystal City Municipal Landfill, under Texas Antiquities Committee Archeology Permit Number 2298. The pedestrian survey was conducted in early January 2000. One prehistoric site (41ZV445), a sparse scatter of burned stone and chipped lithics, was identified and documented. Shovel testing revealed no subsurface cultural deposits. The site does not meet the criteria for potential eligibility to the National Register of Historic Places nor does it warrant State Archaeological Landmark designation. Cultural resource clearance is recommended for the proposed landfill extension

The Technology of Immortality, the Soul, and Human Identity

In this paper, I argue that human beings will soon achieve immortality, but that that immortality will be neither the theistic promise of resurrection of the body nor the soul. Rather, I suggest that technological immortality—the ability through pure techné to reproduce any human life ever lived—is not only possible, but inevitable. Moreover, more than a cursory survey of the biological sciences, computer technology, and fictive literature, this essay also examines the normative dimensions of this near-future reality; ought we or ought we not

Syntheses, Structures, and Photoluminescence of 1-D Lanthanide Coordination Polymers

Five new lanthanide 1-D coordination polymers are reported which are formed from flexible salen type Schiff-base ligands H(2)L and H(2)L' (H(2)L = N, N(1)-ethylene bis(salicylideneimine); H(2)L' = N,N(1)-bis(3-methoxysalicylidene) ethylene-1,2-diamine). The polymeric structures are formed by bridging neutral H(2)L units in the case of {[Ln(2)L(2)(CF(3)SO(3))(H(2)L)(4)(MeOH)]center dot CF(3)SO(3)}(n) (Ln = Eu (1), Nd (2) and Er (3)), and by acetate (OAc(-)) groups in [Yb(2)(L)(2)(OAc)(2)(MeOH)(2)](n) (4) and {[Tb(3)(L')(2)(OAc)(5)]center dot Et(2)O center dot(MeOH)(0.5)}(n) (5). The structures of 1-5 were determined by single crystal X-ray crystallographic studies and the luminescence properties of 1 and 5 in MeOH solution were determined.ong Kong Baptist University FRG/06-07/II-16Hong Kong Research Grants Council HKBU 202407Robert A. Welch Foundation F-816Texas Higher Education Coordinating Board ARP 003658-0010-2006Petroleum Research FundAmerican Chemical Society 47014-AC5Chemistr

Chemical Vapour Deposition of Amorphous Ru(P) Thin Films from Ru Trialkylphosphite Hydride Complexes

The ruthenium phosphite hydride complexes H2Ru(P(OR)(3))(4) (R = Me (1), Et (2), Pr-i (3)) were used as CVD precursors for the deposition of films of amorphous ruthenium-phosphorus alloys. The as-deposited films were X-ray amorphous and XPS analysis revealed that they were predominantly comprised of Ru and P in zero oxidation states. XPS analysis also showed the presence of small amounts of oxidized ruthenium and phosphorus. The composition of the films was found to depend on ligand chemistry as well as the deposition conditions. The use of H-2 as the carrier gas had the effect of increasing the relative concentrations of P and O for all films. Annealing films to 700 degrees C under vacuum produced films of polycrystalline hcp Ru while a flowing stream of H-2 resulted in polycrystalline hcp RuP.Welch Foundation F-816Petroleum Research FundAmerican Chemical Society 47014-ACSNSF 0741973Chemistr