192 research outputs found
The first mononuclear PtIII complex. Molecular structures of (NBu4)[PtIII(C6Cl5)4] and of its parent compound {NBu4}2[PtII(C6Cl5)4]·2CH2Cl2
(NBu4)[PtIII(C6Cl5)4], fully characterized by crystallographic, spectral, and magnetic measurements has been isolated by oxidation with halogens or TICl3 of the parent compound (NBu4)2[PtII(C6CL5)4], which has also been analysed by X-ray crystallography
Synthesis and reactivity of [NBu4]+[Pt(III)(C6Cl5)4]-: molecular structures of [NBu4]2+[Pt(C6Cl5)4]2-.cntdot.2CH2Cl2, [NBu4]+[Pt(III)(C6Cl5)4]- and [NBu4]+[Pt(C6Cl5)4(NO)]-
The synthesis and chemical and spectral characterizations of compounds [ N B ~ ~ ] ~ + [ P t ( c ~(lc)l,~ ) ~ ] ~ -
[NBu ~ ]+[ P ~ (C~(C21~, [~N)B~ ]u-~ ]+[P~(C~CI~)(~31N, aOn]d- [NBU~]+[P~(C~C~,)~(4() ParPe~ d~es)c]ri-be d
in this paper. By far the most intriguing complex is 2, the first mononuclear Pt(II1) complex ever reported.
[NBu4]+[Pt(C&l5),]-( 2) can be prepared by reacting [NBu4]2+[Pt(C,C15)4]2(-1 ) with various oxidants such
as C12, Br2, 12, or T1C13 and also by the electrochemical oxidation of 1 at 0.7 V in CH2C12. Compound 2
is stable to air and moisture, shows very limited reactivity, and has magnetic properties consistent with
a 1/2 spin system. Complex 2 reacts with NO gas to give the adduct [NBu4]'[Pt(C6Cl5),(NO)]- (3), which
can also be made directly from 1 by reaction with [NO]+[ClO,]- under an atmosphere at NO. Attempts
to make the corresponding fluorine analogue of the Pt(II1) complex [NBu4]+[Pt(C6F,),]w- ere unsuccessful.
The X-ray structures of complexes 1-3 have been determined and are also reported in this aper. Complex
3 crystallizes in the tetragonal space group P4,lnbc (no. 1331, with a = b = 14.948 (6) c = 23.488 (9)
8, V = 5248 (3) %r3, and p(calcd) = 1.85 g cm-3 for 2 = 4. The structure has been refined to a final agreement
factor of R = 6.6%
Psychological Help-Seeking among Latin American Immigrants in Canada: Testing a Culturally-Expanded Model of the Theory of Reasoned Action Using Path Analysis
The current study investigated the psychosocial and cultural predictors of psychological help-seeking based on the Theory of Reasoned Action (TRA: Ajzen and Fishbein 1980) in a sample of 223 adult Latin American immigrants living in Canada. Using path analysis, the results provided empirical support for the TRA, as both help-seeking attitudes and subjective norms were found to influence participants’ help-seeking intentions. Moreover, the re-specified culturally-expanded model showed a good fit to the data and revealed the direct and indirect effects that bi-directional acculturation (Latino and Canadian Cultural orientations), familism, and collective coping had on help-seeking intentions. The results point to the integral roles familism and subjective norms of social referents (e.g., parents, siblings) play in the help-seeking decision process among Latin Americans. Limitations, future research directions and clinical implications are considered and discussed
Transition and Group IIB Metal Complexes With “Active Aldehyde” Derivatives of Thiamine
The Zn2+, Cd2+, Hg2+, Co2+ and Ni2+ ions produce zwitterionic type
complexes with the ligands (L), 2-(α-hydroxy-benzyl)thiamine=HBT and 2-(α-hydroxy-cyclohexyl-methyl)thiamine = HCMT, of the type MLCl3. The ligands
are in the S conformation, the metals are bound to N1, of the pyrimidine moiety
of thiamine and the complexes have a trigonally distorted tetrahedral structure,
as the crystal structure of the complex Zn(HCMT)Cl3 (orthorombic, a=14.4 b=14.1
c=17.4 β=105.6O V=3392A3 R=13.8%), the one and two dimensional 1H nmr
spectra of the Zn2+, Cd2+ and Hg2+ complexes and the electronic spectra of the
Co2+ and Ni2+ complexes show. A brief review of the previous techniques
(structure of the Hg(HBT)Cl3 complex, IR-Raman spectra, 13C nmr in solution
and solid state etc) used to characterize these complexes, is also given here and
the proper conclusions drawn
Unique Multiorganizational Collaborative Proves Effective in Delivering 2014 Farm Bill Education
The Agricultural Act of 2014 is critical to the economic safety net for U.S. producers. This act represented a major change in philosophy, requiring producers to make key decisions about their options on the basis of risk management. To add to the complexity of the issue, the time period for delivering applicable education to landowners before sign-up deadlines was relatively short. This article highlights a unique multiorganizational statewide approach to delivering the applicable education. It involved University of Minnesota Extension, the Center for Farm Financial Management, the U.S. Department of Agriculture, and banks and resulted in substantive evaluative outcomes
Oxidative elemental cycling under the low O<sub>2</sub> Eoarchean atmosphere
The Great Oxidation Event signals the first large-scale oxygenation of the atmosphere roughly 2.4 Gyr ago. Geochemical signals diagnostic of oxidative weathering, however, extend as far back as 3.3–2.9 Gyr ago. 3.8–3.7 Gyr old rocks from Isua, Greenland stand as a deep time outpost, recording information on Earth’s earliest surface chemistry and the low oxygen primordial biosphere. Here we find fractionated Cr isotopes, relative to the igneous silicate Earth reservoir, in metamorphosed banded iron formations (BIFs) from Isua that indicate oxidative Cr cycling 3.8–3.7 Gyr ago. Elevated U/Th ratios in these BIFs relative to the contemporary crust, also signal oxidative mobilization of U. We suggest that reactive oxygen species were present in the Eoarchean surface environment, under a very low oxygen atmosphere, inducing oxidative elemental cycling during the deposition of the Isua BIFs and possibly supporting early aerobic biology
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
We measure cosmic weak lensing shear power spectra with the Subaru Hyper
Suprime-Cam (HSC) survey first-year shear catalog covering 137deg of the
sky. Thanks to the high effective galaxy number density of 17
arcmin even after conservative cuts such as magnitude cut of
and photometric redshift cut of , we obtain a high
significance measurement of the cosmic shear power spectra in 4 tomographic
redshift bins, achieving a total signal-to-noise ratio of 16 in the multipole
range . We carefully account for various uncertainties
in our analysis including the intrinsic alignment of galaxies, scatters and
biases in photometric redshifts, residual uncertainties in the shear
measurement, and modeling of the matter power spectrum. The accuracy of our
power spectrum measurement method as well as our analytic model of the
covariance matrix are tested against realistic mock shear catalogs. For a flat
cold dark matter (CDM) model, we find for
( for ) from our HSC tomographic
cosmic shear analysis alone. In comparison with Planck cosmic microwave
background constraints, our results prefer slightly lower values of ,
although metrics such as the Bayesian evidence ratio test do not show
significant evidence for discordance between these results. We study the effect
of possible additional systematic errors that are unaccounted in our fiducial
cosmic shear analysis, and find that they can shift the best-fit values of
by up to in both directions. The full HSC survey data
will contain several times more area, and will lead to significantly improved
cosmological constraints.Comment: 43 pages, 21 figures, accepted for publication in PAS
Torsional Sensor Applications in Two-Phase Fluids
A solid corrosion-resistant torsional waveguide of diamond cross section has been developed to sense on-line and in real-time the characteristics of the liquid in which it is submerged. The sensor can measure, among other things, the liquid content of a bubbly medium; the density of adjacent pure liquids; the equivalent density of liquid-vapor mixtures or particulate suspensions; a suspension\u27s concentration; and the liquid level. The sensor exploits the phenomenon that the speed of propagation of a torsional stress wave in a submerged waveguide with a noncircular cross section is inversely proportional to the equivalent density of the liquid in which the waveguide is submerged. The sensor may be used to conduct measurements along distances ranging from 20 mm to 20 m and over a wide range of temperatures and pressures, e.g., from the cryogenic temperature of liquid nitrogen, -196°C, up to hot pressurized water at 300°C and 7 MPa. A self-calibrating three-zone sensor and associated electronics have also been developed to compensate for any sensor inaccuracies due to operation over a wide range of temperature. In some of the water experiments at room temperature, unexpected attenuation of the guided torsional waves was observed. This excess attenuation depends in part on the waveguide\u27s surface finish. It appears to be caused by air microbubbles adhering to the waveguide, imposing one of the practical limits on the maximum sensor length in nondegassed or aerated water
Structure of acostatin, a dimeric disintegrin from Southern copperhead (Agkistrodon contortrix contortrix), at 1.7 Å resolution
Disintegrins are a family of small (4–14 kDa) proteins that bind to another class of proteins, integrins. Therefore, as integrin inhibitors, they can be exploited as anticancer and antiplatelet agents. Acostatin, an αβ heterodimeric disintegrin, has been isolated from the venom of Southern copperhead (Agkistrodon contortrix contortrix). The three-dimensional structure of acostatin has been determined by macromolecular crystallography using the molecular-replacement method. The asymmetric unit of the acostatin crystals consists of two heterodimers. The structure has been refined to an R_(work) and R_(free) of 18.6% and 21.5%, respectively, using all data in the 20–1.7 Å resolution range. The structure of all subunits is similar and is well ordered into N-terminal and C-terminal clusters with four intramolecular disulfide bonds. The overall fold consists of short β-sheets, each of which is formed by a pair of antiparallel β-strands connected by β-turns and flexible loops of different lengths. Conformational flexibility is found in the RGD loops and in the C-terminal segment. The interaction of two N-terminal clusters via two intermolecular disulfide bridges anchors the αβ chains of the acostatin dimers. The C-terminal clusters of the heterodimer project in opposite directions and form a larger angle between them in comparison with other dimeric disintegrins. Extensive interactions are observed between two heterodimers, revealing an αββα acostatin tetramer. Further experiments are required to identify whether the αββα acostatin complex plays a functional role in vivo
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