879 research outputs found

    Externally Dispersed Interferometry for Precision Radial Velocimetry

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    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic spectral comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. The moire pattern shifts in phase in response to a Doppler shift. Moire patterns are broader than the underlying spectral features and more easily survive spectrograph blurring and common distortions. Thus, the EDI technique allows lower resolution spectrographs having relaxed optical tolerances (and therefore higher throughput) to return high precision velocity measurements, which otherwise would be imprecise for the spectrograph alone.Comment: 7 Pages, White paper submitted to the AAAC Exoplanet Task Forc

    Is Workstyle a Mediating Factor for Pain in the Upper Extremity Over Time?

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    Introduction Upper extremity musculoskeletal disorders influence workers’ quality of life. Workstyle may be one factor to deal with in workers with pain in the upper extremity. The objective of this study was to determine if workstyle is a mediating factor for upper extremity pain in a changing work environment of office workers over time. Methods Office workers with upper extremity pain filled out a Workstyle questionnaire (WSF) at baseline (n = 110). After 8 and 12 months follow-up assessment took place. Participants were divided into a good and an adverse workstyle group at baseline. The presence of upper extremity pain in both groups was calculated and relative risks were determined. Chi-square tests were used. Results Eight months after baseline, 80% of the adverse and 45% of the good workstyle group reported pain. The relative risk (RR) of having upper extremity pain for the adverse compared to the good workstyle group was 1.8 (95% CI 1.08–2.86) (P = 0.055). Twelve months after baseline, upper extremity pain was more often presented in the adverse workstyle compared to the good workstyle group (RR = 3.0, (95% CI 1.76–5.11), P = 0.003). Twelve months after baseline, 100% of the adverse workstyle group and 33% of the good workstyle group reported pain in the upper extremity. Conclusion Workstyle seems to be a mediating factor for upper extremity pain in office workers in a changing work environment. It is recommended to assess workstyle among office workers with upper extremity pain, and to include workstyle behaviour in treatments

    Long-Term Survival Rates after Resection for Locally Advanced Kidney Cancer: Memorial Sloan Kettering Cancer Center 1989 to 2012 Experience

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    Purpose: We analyzed the 23-year Memorial Sloan Kettering Cancer Center experience with surgical resection, and concurrent adrenalectomy and lymphadenectomy for locally advanced nonmetastatic renal cell carcinoma. Materials and Methods: We retrospectively reviewed the records of 802 patients who underwent nephrectomy with or without concurrent adrenalectomy or lymphadenectomy for locally advanced renal cell carcinoma, defined as stage T3 or greater and M0. Patients who received adjuvant treatment within 3 months of surgery or had fewer than 3 months of followup or bilateral renal masses at presentation were excluded from analysis. Five and 10-year progression-free and overall survival was estimated by the Kaplan-Meier method. Differences between groups were analyzed by the log rank test. Results: A total of 596 (74%) and 206 patients (26%) underwent radical and partial nephrectomy, respectively. Renal cell carcinoma progressed in 189 patients and 104 died of the disease. Median followup in patients without progression was 4.6 years. Symptoms at presentation, ASA (R) classification, tumor stage, histological subtype, grade and lymph node status were significantly associated with progression-free and overall survival. On multivariate analysis adrenalectomy use decreased with time but lymphadenectomy use increased (OR 0.82 vs 1.16 per year). Larger tumors were associated with a higher likelihood of concurrent adrenalectomy and lymphadenectomy. Conclusions: In our series of patients with locally advanced nonmetastatic renal cell carcinoma survival was favorable in those in good health who were asymptomatic at presentation with T3 tumors and negative lymph nodes. Further, there has been a trend toward more selective use of adrenalectomy and increased use of lymphadenectomy

    Efficient Blue Phosphorescence in Gold(I)‐Acetylide Functionalized Coinage Metal Bis(amidinate) Complexes

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    The synthesis of linear symmetric ethynyl‐ and acetylide‐amidinates of the coinage metals is presented. Starting with the desilylation of the complexes [{Me3_{3}SiC≡CC(NDipp)2_{2}}2_{2}M2_{2}] (Dipp=2,6‐diisopropylphenyl) (M=Cu, Au) it is demonstrated that this compound class is suitable to serve as a versatile metalloligand. Deprotonation with n‐butyllithium and subsequent salt metathesis reactions yield symmetric tetranuclear gold(I) acetylide complexes of the form [{(PPh3_{3})AuC≡CC(NDipp)2_{2}}2_{2}M2_{2}] (M=Cu, Au). The corresponding Ag complex [{(PPh3_{3})AuC≡CC(NDipp)2_{2}}2_{2}Ag2_{2}] was obtained by a different route via metal rearrangement. All compounds show bright blue or blue‐green microsecond long phosphorescence in the solid state, hence their photophysical properties were thoroughly investigated in a temperature range of 20–295 K. Emission quantum yields of up to 41 % at room temperature were determined. Furthermore, similar emissions with quantum yields of 15 % were observed for the two most brightly luminescent complexes in thf solution

    Completing the triad: Synthesis and full characterization of homoleptic and heteroleptic carbonyl and nitrosyl complexes of the group VI metals

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    Oxidation of M(CO)6_{6} (M = Cr, Mo, W) with the synergistic oxidative system Ag[WCA]/0.5 I2_{2} yields the fully characterized metalloradical salts [M(CO)6_{6}]+˙[WCA]− (weakly coordinating anion WCA = [F-{Al(ORF^{F})3_{3}}2_{2}]−^{-}, RF^{F} = C(CF3_{3})3_{3}). The new metalloradical cations with M = Mo and W showcase a similar structural fluxionality as the previously reported [Cr(CO)6_{6}]+^{+}˙. Their reactivity increases from M = Cr < Mo < W and their syntheses allow for in-depth insights into the properties of the group 6 carbonyl triad. Furthermore, the reaction of NO+^{+}[WCA]−^{-} with neutral carbonyl complexes M(CO)6_{6} gives access to the heteroleptic carbonyl/nitrosyl cations [M(CO)5_{5}(NO)]+^{+} as salts of the WCA [Al(ORF)4_{4}]−^{-}, the first complete transition metal triad of their kind

    Alkali Metal Complexes of a Bis(diphenylphosphino)methane Functionalized Amidinate Ligand: Synthesis and Luminescence

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    A novel bis(diphenylphosphino)methane (DPPM) functionalized amidine ligand (DPPM−C(N-Dipp)2_{2}H) (Dipp=2,6-diisopropylphenyl) was synthesized. Subsequent deprotonation with suitable alkali metal bases resulted in the corresponding complexes [M{DPPM−C(N-Dipp)2_{2}}(Ln)] (M=Li, Na, K, Rb, Cs; L=thf, Et2_{2}O). The alkali metal complexes form monomeric species in the solid state, exhibiting intramolecular metal-π-interactions. In addition, a caesium derivative [Cs{PPh2_{2}CH2_{2}-C(N-Dipp)2_{2}}]6_{6} was obtained by cleavage of a diphenylphosphino moiety, forming an unusual six-membered ring structure in the solid state. All complexes were fully characterized by single crystal X-ray diffraction, NMR spectroscopy, IR spectroscopy as well as elemental analysis. Furthermore, the photoluminescent properties of the complexes were thoroughly investigated, revealing differences in emission with regards to the respective alkali metal. Interestingly, the hexanuclear [Cs{PPh2_{2}CH2_{2}-C(N-Dipp)2_{2}}]6_{6} metallocycle exhibits a blue emission in the solid state, which is significantly red-shifted at low temperatures. The bifunctional design of the ligand, featuring orthogonal donor atoms (N vs. P) and a high steric demand, is highly promising for the construction of advanced metal and main group complexes
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