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

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

Rhodium Pyrazolate Complexes as Potential CVD Precursors

Reaction of 3,5-(CF3)(2)PzLi with [Rh(mu-Cl)(eta(2)-C2H4)(2)](2) or [Rh(mu-Cl)(PMe3)(2)](2) in Et2O gave the dinuclear complexes [Rh(eta(2)-C2H4)(2)(mu-3,5-(CF3)(2)-Pz)](2) (1) and [Rh-2(mu-Cl)(mu-3,5-(CF3)(2)-Pz) (PMe3)(4)] (2) respectively (3,5-(CF3)(2)Pz = bis-trifluoromethyl pyrazolate). Reaction of PMe3 with [Rh(COD)(mu-3,5-(CF3)(2)-Pz)](2) in toluene gave [Rh(3,5-(CF3)(2)-Pz)(PMe3)(3)] (3). Reaction of 1 and 3 in toluene (1 : 4) gave moderate yields of the dinuclear complex [Rh(PMe3)(2)(mu-3,5-(CF3)(2)-Pz)](2) (4). Reaction of 3,5-(CF3)(2)PzLi with [Rh(PMe3)(4)]Cl in Et2O gave the ionic complex [Rh(PMe3)(4)][3,5-(CF3)(2)-Pz] (5). Two of the complexes, 1 and 3, were studied for use as CVD precursors. Polycrystalline thin films of rhodium (fcc-Rh) and metastable-amorphous films of rhodium phosphide (Rh2P) were grown from 1 and 3 respectively at 170 and 130 degrees C, 0.3 mmHg in a hot wall reactor using Ar as the carrier gas (5 cc min(-1)). Thin films of amorphous rhodium and rhodium phosphide (Rh2P) were grown from 1 and 3 at 170 and 130 degrees C respectively at 0.3 mmHg in a hot wall reactor using H-2 as the carrier gas (7 cc min(-1)).Welch Foundation F-816Petroleum Research Fund 47014-ACSNSF 0741973Chemistr

Portable Microleak-Detection System

The figure schematically depicts a portable microleak-detection system that has been built especially for use in testing hydrogen tanks made of polymer-matrix composite materials. (As used here, microleak signifies a leak that is too small to be detectable by the simple soap-bubble technique.) The system can also be used to test for microleaks in tanks that are made of other materials and that contain gases other than hydrogen. Results of calibration tests have shown that measurement errors are less than 10 percent for leak rates ranging from 0.3 to 200 cm3/min. Like some other microleak-detection systems, this system includes a vacuum pump and associated plumbing for sampling the leaking gas, and a mass spectrometer for analyzing the molecular constituents of the gas. The system includes a flexible vacuum chamber that can be attached to the outer surface of a tank or other object of interest that is to be tested for leakage (hereafter denoted, simply, the test object). The gas used in a test can be the gas or vapor (e.g., hydrogen in the original application) to be contained by the test object. Alternatively, following common practice in leak testing, helium can be used as a test gas. In either case, the mass spectrometer can be used to verify that the gas measured by the system is the test gas rather than a different gas and, hence, that the leak is indeed from the test object

Drag Prediction for the DLR-F6 Wing/Body and DPW Wing using CFL3D and OVERFLOW Overset Mesh

A series of overset grids was generated in response to the 3rd AIAA CFD Drag Prediction Workshop (DPW-III) which preceded the 25th Applied Aerodynamics Conference in June 2006. DPW-III focused on accurate drag prediction for wing/body and wing-alone configurations. The grid series built for each configuration consists of a coarse, medium, fine, and extra-fine mesh. The medium mesh is first constructed using the current state of best practices for overset grid generation. The medium mesh is then coarsened and enhanced by applying a factor of 1.5 to each (I,J,K) dimension. The resulting set of parametrically equivalent grids increase in size by a factor of roughly 3.5 from one level to the next denser level. CFD simulations were performed on the overset grids using two different RANS flow solvers: CFL3D and OVERFLOW. The results were post-processed using Richardson extrapolation to approximate grid converged values of lift, drag, pitching moment, and angle-of-attack at the design condition. This technique appears to work well if the solution does not contain large regions of separated flow (similar to that seen n the DLR-F6 results) and appropriate grid densities are selected. The extra-fine grid data helped to establish asymptotic grid convergence for both the OVERFLOW FX2B wing/body results and the OVERFLOW DPW-W1/W2 wing-alone results. More CFL3D data is needed to establish grid convergence trends. The medium grid was utilized beyond the grid convergence study by running each configuration at several angles-of-attack so drag polars and lift/pitching moment curves could be evaluated. The alpha sweep results are used to compare data across configurations as well as across flow solvers. With the exception of the wing/body drag polar, the two codes compare well qualitatively showing consistent incremental trends and similar wing pressure comparisons

Flexible Plug Repair for Shuttle Wing Leading Edge

In response to the Columbia Accident Investigation Board report, a plug repair kit has been developed to enable astronauts to repair the space shuttle's wing leading edge (WLE) during orbit. The plug repair kit consists of several 17.78- cm-diameter carbon/silicon carbide (C/SiC) cover plates of various curvatures that can be attached to the refractory carbon-carbon WLE panels using a TZM refractory metal attach mechanism. The attach mechanism is inserted through the damage in the WLE panel and, as it is tightened, the cover plate flexes to conform to the curvature of the WLE panel within 0.050 mm. An astronaut installs the repair during an extravehicular activity (EVA). After installing the plug repair, edge gaps are checked and the perimeter of the repair is sealed using a proprietary material, developed to fill cracks and small holes in the WLE

Early High-Dose Vitamin D3 for Critically Ill, Vitamin D-Deficient Patients

BACKGROUND: Vitamin D deficiency is a common, potentially reversible contributor to morbidity and mortality among critically ill patients. The potential benefits of vitamin D supplementation in acute critical illness require further study. METHODS: We conducted a randomized, double-blind, placebo-controlled, phase 3 trial of early vitamin D3 supplementation in critically ill, vitamin D-deficient patients who were at high risk for death. Randomization occurred within 12 hours after the decision to admit the patient to an intensive care unit. Eligible patients received a single enteral dose of 540,000 IU of vitamin D3 or matched placebo. The primary end point was 90-day all-cause, all-location mortality. RESULTS: A total of 1360 patients were found to be vitamin D-deficient during point-of-care screening and underwent randomization. Of these patients, 1078 had baseline vitamin D deficiency (25-hydroxyvitamin D level,[50 nmol per liter]) confirmed by subsequent testing and were included in the primary analysis population. The mean day 3 level of 25-hydroxyvitamin D was 46.9±23.2 ng per milliliter (117±58 nmol per liter) in the vitamin D group and 11.4±5.6 ng per milliliter (28±14 nmol per liter) in the placebo group (difference, 35.5 ng per milliliter; 95% confidence interval [CI], 31.5 to 39.6). The 90-day mortality was 23.5% in the vitamin D group (125 of 531 patients) and 20.6% in the placebo group (109 of 528 patients) (difference, 2.9 percentage points; 95% CI, -2.1 to 7.9; P = 0.26). There were no clinically important differences between the groups with respect to secondary clinical, physiological, or safety end points. The severity of vitamin D deficiency at baseline did not affect the association between the treatment assignment and mortality. CONCLUSIONS: Early administration of high-dose enteral vitamin D3 did not provide an advantage over placebo with respect to 90-day mortality or other, nonfatal outcomes among critically ill, vitamin D-deficient patients. METHODS: We conducted a randomized, double-blind, placebo-controlled, phase 3 trial of early vitamin D3 supplementation in critically ill, vitamin D-deficient patients who were at high risk for death. Randomization occurred within 12 hours after the decision to admit the patient to an intensive care unit. Eligible patients received a single enteral dose of 540,000 IU of vitamin D3 or matched placebo. The primary end point was 90-day all-cause, all-location mortality

Building robust, practicable counterfactuals and scenarios to evaluate the impact of species conservation interventions using inferential approaches

Robust evaluation of the impact of biodiversity conservation actions is important not only for ensuring that conservation strategies are effective and maximise return on investment, but also to identify and celebrate successful conservation strategies. This evaluation can be retrospective (comparing the current situation to a counterfactual scenario) or forward-looking (comparing future scenarios with or without conservation). However, assessment of impact using experimental or quasi-experimental designs is typically difficult in conservation, so rigorous inferential approaches are required. Inferential assessment of impact is a key part of the new IUCN Green Status of Species, which greatly amplifies the need for standardised and practical species impact evaluation methods. Here, we use the Green Status of Species method as a base to review how inferential methods can be used to evaluate conservation impact at the species level. We identify three key components of the inferential impact evaluation process—estimation of scenario outcomes, selection of baseline scenario, and frame of reference—and explain, with examples, how to reduce the subjectivity of these steps. We propose a step-by-step guide, incorporating these principles, that can be used to infer scenario outcomes in order to evaluate past and future conservation impact in a wide range of situations, not just Green Status of Species assessments. We recommend that future non-experimental conservation interventions facilitate the process of evaluating impact by identifying the variable(s) that will be used to measure impact at the design stage, and by using conceptual models to help choose conservation actions most likely to have the desired impact