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Czochralski growth of large metallic alloy single crystals of Al13Co4and Al13Fe4from Alrich solutions has been demonstrated for the first time. A detailed description of all decisive steps of the growth procedure is given with particular emphasis to seeding from a native phase as well as spontaneous nucleation if no seed crystal from a preceding experiment is available. Czochralski growth in a hightemperature solution system requires much lower pulling rates compared to typical growth experiments from the melt and a timedependent temperature program to compensate the change of the liquidus temperature that results from the permanently increasing Al content of the liquid phase. With a given amount of the initial melt, the size of the Al13Co4crystals is limited by the rather narrow temperature range of the Al13Co4primary crystallization window, followed by Al9Co2phase crystallization. In the AlFe system, despite the huge temperature range of equilibrium between Al13Fe4and its Alrich melt, Czochralski growth of Al13Fe4is restricted to higher temperatures due to the limited solubility that leads to mother liquid inclusions even at extremely low pulling rates. © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

The scope of CCC−NHC pincer complex synthetic methodology by metalation/transmetalation has been extended to Ir. Structural characterization revealed that it is isomorphous with the Rh complex. Both Rh and Ir complexes are efficient catalysts for the hydroamination/cyclization of secondary amines in the presence of air and/or water. [ABSTRACT FROM AUTHOR]

Reactions of trans-(C6F5)L2PtCl (2, L = Ph2P(CH2)4O(CH2)2CH=CH2; 6, L = Ph2P(CH2)2C(CH3)2(CH2)3CH=CH2) and H(C≡C)2H (HNEt2, cat. CuI) give trans-(C6F5)L2Pt(C≡C)2H (3, 7; 86–97%). Oxidative homocouplings (O2, cat. CuCl/TMEDA, acetone) yield trans,trans-(C6F5)L2Pt(C≡C)4PtL2(C6F5) (4, 8; 75–86%). Reactions with Grubbs’ catalyst, followed by hydrogenation, give mainly trans,trans-(C6F5)(Ph2┌P(CH2)4O(CH2)6O(CH2)4PPh2)Pt(C≡C)4Pt(Ph2P(CH2)4O(CH2)6O(CH2)4PPh2)(C6F5) (5), with termini-spanning diphosphines, and trans,trans-(C6F5)(Ph2┌P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2)Pt(C≡C)4┌Pt(Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2)(C6F5) (9), with trans-spanning diphosphines, respectively. Reactions of trans,trans-(C6F5)(p-tol3P)2Pt(C≡C)4Pt(Pp-tol3)2(C6F5) with Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2 and p-tol2P(CH2)3(CF2)8(CH2)3Pp-tol2 give 10 (70%), the isomer of 9 with termini-spanning diphosphines, and the analogous adduct of the fluorinated diphosphine. However, the latter oligomerizes upon attempted workup. The crystal structure of 5 shows that the sp3 chains adopt a chiral double-helical conformation about the sp chain, with the endgroups defining a 164.1° angle. Additional conformational properties of the preceding complexes are analyzed in detail, and dynamic properties are probed by low temperature NMR experiments. [ABSTRACT FROM AUTHOR]

The complexation reactions of 1 : 1 molar ratios of M(NO3)3·nH2O (M = Y, La–Pr, Sm–Lu) and pentaethylene glycol (EO5) in 3 : 1 CH3CN : CH3OH were investigated. Crystalline complexes were isolated for all metals investigated and X-ray structural analyses performed. The M(NO3)3–EO5 complexes structurally characterized are remarkably similar to the corresponding 18-crown-6 complexes. Six structurally unique types of anhydrous complexes with the early- to mid-lanthanides (M = La–Nd, Sm–Dy) were found. For the largest metals studied, the twelve coordinate species [M(NO3)3(EO5)] (M = La, Ce) were isolated. A second form of the type [Ce(NO3)2(EO5)]7[Ce(NO3)6][NO3]4 was isolated for M = Ce from the same reaction mixture as the above complex. Praseodymium through dysprosium form ten coordinate species which all have the same basic formula, [M(NO3)2(EO5)][NO3], however, four structurally unique forms have been characterized with the major differences between each arising from the way in which the uncoordinated nitrate anion is hydrogen bonded to the glycol ligand, and the glycol conformation. The smallest lanthanides investigated, M = Ho–Lu, Y, form outer-sphere complexes [M(OH2)3(NO3)3]·EO5. Structural results suggest that the flexibility of the acyclic EO5 ligand allows for the formation of inner sphere complexes across most of the series, whereas the cyclic 18-crown-6 is too constrained to permit such complexation to the mid- to late-lanthanides. [ABSTRACT FROM AUTHOR]

In Experiment 1 underwater visual acuity was assessed in two Florida manatees, Trichechus manatus latirostris, using grating stimuli in three conditions: Vertical gratings presented in freshwater, vertical gratings in saltwater, and horizontal gratings in saltwater. All stimuli were tested in a free-swimming format from a minimum distance of one meter. Substantial differences were found between the two subjects. One subject's minimum angles of resolution (MAR) were 56 min for vertical stimuli in freshwater, 38 min for vertical stimuli in saltwater, and 24 min for horizontal grating stimuli in saltwater. When only trials under brightest light conditions were analyzed, MARs improved for vertical stimuli to 24 min in freshwater and 21 min in saltwater. No improvement was found for horizontal stimuli with brighter light conditions. The MARs of the second subject measured over a degree for all test conditions. In Experiment 2 only the first subject was tested from a closer viewing distance. He showed no improvement when allowed to approach targets to within 30 cm. The limited resolution of both subjects and absence of increased acuity at closer distances in one suggests that manatees use vision for intermediate or longer distance inspection of large objects. The disparity in visual resolution between subjects has possible implications for variability in acuity within the species. [ABSTRACT FROM AUTHOR]

Reports on a study about centenarians in Sweden. Purpose, which was to describe the population from physical, social and psychological points of view as well as to characterize centenarians with various health conditions and diverse degrees of autonomy and life satisfaction, and to identify factors which predict future survival; Methods; Results; Conclusion.

We report the discovery of the first short-period binary in which a hot subdwarf star (sdOB) filled its Roche lobe and started mass transfer to its companion. The object was discovered as part of a dedicated high-cadence survey of the Galactic plane named the Zwicky Transient Facility and exhibits a period of P = 39.3401(1) minutes, making it the most compact hot subdwarf binary currently known. Spectroscopic observations are consistent with an intermediate He-sdOB star with an effective temperature of = 42,400 ± 300 K and a surface gravity of = 5.77 ± 0.05. A high signal-to-noise ratio GTC+HiPERCAM light curve is dominated by the ellipsoidal deformation of the sdOB star and an eclipse of the sdOB by an accretion disk. We infer a low-mass hot subdwarf donor with a mass MsdOB = 0.337 ± 0.015 and a white dwarf accretor with a mass MWD = 0.545 ± 0.020 . Theoretical binary modeling indicates the hot subdwarf formed during a common envelope phase when a 2.5–2.8 star lost its envelope when crossing the Hertzsprung gap. To match its current , , , and masses, we estimate a post–common envelope period of ≈ 150 minutes and find that the sdOB star is currently undergoing hydrogen shell burning. We estimate that the hot subdwarf will become a white dwarf with a thick helium layer of ≈0.1 , merge with its carbon/oxygen white dwarf companion after ≈17 Myr, and presumably explode as a thermonuclear supernova or form an R CrB star. [ABSTRACT FROM AUTHOR]

Some binary systems composed of a white dwarf (WD) and a hot subdwarf (sdB) helium star will make contact within the helium burning lifetime of the sdB star. The accreted helium on the WD inevitably undergoes a thermonuclear instability, causing a detonation that is expected to transition into the WD core and lead to a thermonuclear supernova (SN) while the donor orbits nearby with high velocity. Motivated by the recent discovery of fast moving objects that occupy unusual locations on the HR diagram, we explore the impact of the thermonuclear SNe on the donors in this specific double detonation scenario. We use MESA to model the binary up to the moment of detonation, then 3D Athena++ to model the hydrodynamic interaction of the SN ejecta with the donor star, calculating the amount of mass that is stripped and the entropy deposited in the deep stellar interior by the strong shock that traverses it. We show that these donor remnants are ejected with velocities primarily set by their orbital speeds: 700–900 km s−1. We model the long-term thermal evolution of remnants by introducing the shock entropy into MESA models. In response to this entropy change, donor remnants expand and brighten for timescales ranging from 106 to 108 yr, giving ample time for these runaway stars to be observed in their inflated state before they leave the galaxy. Even after surface layers are stripped, some donors retain enough mass to resume core helium burning and further delay fading for more than 108 yr. [ABSTRACT FROM AUTHOR]

Many isolated white dwarfs (WDs) show spectral evidence of atmospheric metal pollution. Since heavy-element sedimentation timescales are short, this most likely indicates ongoing accretion. Accreted metals encounter a variety of mixing processes at the WD surface: convection, gravitational sedimentation, overshoot, and thermohaline instability. We present MESA WD models that explore each of these processes and their implications for inferred accretion rates. We provide diffusion timescales for many individual metals, and we quantify the regimes in which thermohaline mixing dominates over gravitational sedimentation in setting the effective settling rate of the heavy elements. We build upon and confirm earlier work finding that accretion rates as high as are needed to explain the observed pollution in DA WDs for Teff > 15,000 K, and we provide tabulated results from our models that enable accretion rate inferences from observations of polluted DA WDs. If these rates are representative of young WDs, we estimate that the total mass of planetesimal material accreted over a WD lifetime may be as high as , though this estimate is susceptible to potential selection biases and uncertainties about the nature of disk processes that supply accretion to the WD surface. We also find that polluted DB WDs experience much less thermohaline mixing than DA WDs, and we do not expect thermohaline instability to be active for polluted DB WDs with . [ABSTRACT FROM AUTHOR]

White dwarfs (WDs) that accrete helium at rates , such as those in close binaries with sdB stars, can accumulate large () helium envelopes, which are likely to detonate. We perform binary stellar evolution calculations of sdB+WD binary systems with MESA, incorporating the important reaction chain (NCO), including a recent measurement for the rate. In large accreted helium shells, the NCO reaction chain leads to ignitions at the dense base of the freshly accreted envelope, in contrast to ignitions, which occur away from the base of the shell. In addition, at these accretion rates, the shells accumulate on a timescale comparable to their thermal time, leading to an enhanced sensitivity of the outcome on the accretion rate history. Hence, time dependent accretion rates from binary stellar evolution are necessary to determine the helium layer mass at ignition. We model the observed sdB+WD system CD and find that the inclusion of these effects predicts ignition of a helium shell, nearly a factor of two larger than previous predictions. A shell with this mass will ignite dynamically, a necessary condition for a helium shell detonation. [ABSTRACT FROM AUTHOR]

A set of iron(ii) complexes of the general formula [Fe(OTf)2L2] was synthesized in 32 to 78% isolated yields, where L represents a bidentate α-iminopyridine ligand. Four of the iron complexes were characterized structurally, revealing a rich coordination chemistry, because the coordination geometry of the iron complexes strongly depends on the substitution pattern exhibited by the ligands L. The catalytic activity of the new complexes was demonstrated in the oxidation of cyclohexane, activated methylene groups and secondary alcohols to the corresponding ketones utilizing H2O2and t-BuOOH as the oxidants. The oxidation of activated methylene groups and secondary alcohols to the corresponding ketones with t-BuOOH gave isolated yields between 22 and 91% (4 h, room temperature, 3% catalyst load). The influence of the structure of the ligand on the activity of the corresponding metal complex is also reported. Furthermore, UV-vis experiments were performed which provided evidence for the formation of an [Fe-O-O-t-Bu] intermediate. [ABSTRACT FROM AUTHOR]

Most massive stars end their lives as red supergiants (RSGs), a short-lived evolutionary phase when they are known to pulsate with varying amplitudes. The RSG period–luminosity (PL) relation has been measured in the Milky Way, the Magellanic Clouds and M33 for about 120 stars in total. Using over 1500 epochs of R-band monitoring from the Palomar Transient Factory survey over a five-year period, we study the variability of 255 spectroscopically cataloged RSGs in M31. We find that all RGSs brighter than MK ≈ −10 mag (log(L/L⊙) > 4.8) are variable at ΔmR > 0.05 mag. Our period analysis finds 63 with significant pulsation periods. Using the periods found and the known values of MK for these stars, we derive the RSG PL relation in M31 and show that it is consistent with those derived earlier in other galaxies of different metallicities. We also detect, for the first time, a sequence of likely first-overtone pulsations. Comparison to stellar evolution models from MESA confirms the first-overtone hypothesis and indicates that the variable stars in this sample have 12 M⊙ < M < 24 M⊙. As these RSGs are the immediate progenitors to Type II-P core-collapse supernovae (SNe), we also explore the implication of their variability in the initial-mass estimates for SN progenitors based on archival images of the progenitors. We find that this effect is small compared to the present measurement errors. [ABSTRACT FROM AUTHOR]

We have previously demonstrated preclinical in vivo targeting of prostate stem cell antigen (PSCA) using a humanized anti-PSCA 2B3 monoclonal antibody (mAb). However, humanization resulted in 5-fold loss of apparent affinity relative to the parental mAb (1 nM). In this study, diabodies (scFv dimers of 55 kDa) were generated from 2B3 including variants with different linker lengths as well as back-mutations to original murine residues to improve affinity. Parental 2B3 (p2B3) and back-mutated 2B3 (bm2B3) diabodies (Dbs) with five- or eight-amino acid linkers (p2B3-Db5, p2B3-Db8, bm2B3-Db5 and bm2B3-Db8) were evaluated for binding to PSCA by flow cytometry and affinities were determined by surface plasmon resonance. Back-mutation restored the affinity from 5.4 to 1.9 nM. Stability, evaluated by size exclusion, revealed that diabodies with eight-residue linkers existed as a mixture of dimeric and monomeric species at low concentrations (≤1 mg/ml). Shortening the linker from eight to five residues improved dimer stability, notably in the bm2B3-Db8 compared with bm2B3-Db5. Both p2B3-Db8 and bm2B3-Db8 were radioiodinated with 124I and evaluated by serial micro-positron emission tomography imaging in mice bearing LAPC-9 human prostate cancer xenografts. Localization in LAPC-9 xenografts was seen at 4 h, whereas at 20 h most of the activity had cleared from the tumor. Highest tumor-to-background contrast ratios and best images were obtained at 12 h. Although the higher affinity bm2B3-Db8 demonstrated improved tumor retention at later time points (20 h), it did not improve tumor targeting or imaging compared with p2B3-Db8 at 12 h. [ABSTRACT FROM AUTHOR]