Experimental constraints on the γ\gamma-ray strength function in 90^{90}Zr using partial cross sections of the 89^{89}Y(p,γ\gamma)90^{90}Zr reaction

Partial cross sections of the $^{89}$Y(p,$\gamma$)$^{90}$Zr reaction have been measured to investigate the $\gamma$-ray strength function in the neutron-magic nucleus $^{90}$Zr. For five proton energies between $E_p=3.65$ MeV and $E_p=4.70$ MeV, partial cross sections for the population of seven discrete states in $^{90}$Zr have been determined by means of in-beam $\gamma$-ray spectroscopy. Since these $\gamma$-ray transitions are dominantly of $E1$ character, the present measurement allows an access to the low-lying dipole strength in $^{90}$Zr. A $\gamma$-ray strength function based on the experimental data could be extracted, which is used to describe the total and partial cross sections of this reaction by Hauser-Feshbach calculations successfully. Significant differences with respect to previously measured strength functions from photoabsorption data point towards deviations from the Brink-Axel hypothesis relating the photo-excitation and de-excitation strength functions.Comment: 5 pages, 5 figure

Lifetime measurement of excited low-spin states via the (p,p′γ(p,p^{\prime}\gamma) reaction

In this article a method for lifetime measurements in the sub-picosecond regime via the Doppler-shift attenuation method (DSAM) following the inelastic proton scattering reaction is presented. In a pioneering experiment we extracted the lifetimes of 30 excited low-spin states of $^{96}$Ru, taking advantage of the coincident detection of scattered protons and de-exciting $\gamma$-rays as well as the large number of particle and $\gamma$-ray detectors provided by the SONIC@HORUS setup at the University of Cologne. The large amount of new experimental data shows that this technique is suited for the measurement of lifetimes of excited low-spin states, especially for isotopes with a low isotopic abundance, where $(n,n^{\prime}\gamma$) or - in case of investigating dipole excitations - ($\gamma,\gamma^{\prime}$) experiments are not feasible due to the lack of sufficient isotopically enriched target material

Possible experimental signature of octupole correlations in the 02+^+_2 states of the actinides

$J^{\pi}$= 0$^+$ states have been investigated in the actinide nucleus ${}^{240}$Pu up to an excitation energy of 3 MeV with a high-resolution (p,t) experiment at $E_{p}$= 24 MeV. To test the recently proposed $J^{\pi}$= 0$^+_2$ double-octupole structure, the phenomenological approach of the spdf-interacting boson model has been chosen. In addition, the total 0$^+$ strength distribution and the $0^+$ strength fragmentation have been compared to the model predictions as well as to the previously studied (p,t) reactions in the actinides. The results suggest that the structure of the 0$^+_2$ states in the actinides might be more complex than the usually discussed pairing isomers. Instead, the octupole degree of freedom might contribute significantly. The signature of two close-lying 0$^+$ states below the 2-quasiparticle energy is presented as a possible manifestation of strong octupole correlations in the structure of the 0$^+_2$ states in the actinides.Comment: 6 pages, 5 figures, published in Phys. Rev. C 88, 041303(R) (2013

NF-κB p50 facilitates neutrophil accumulation during LPS-induced pulmonary inflammation

BACKGROUND: Transcription factors have distinct functions in regulating immune responses. During Escherichia coli pneumonia, deficiency of NF-κB p50 increases gene expression and neutrophil recruitment, suggesting that p50 normally limits these innate immune responses. p50-deficient mice were used to determine how p50 regulates responses to a simpler, non-viable bacterial stimulus in the lungs, E. coli lipopolysaccharide (LPS). RESULTS: In contrast to previous results with living E. coli, neutrophil accumulation elicited by E. coli LPS in the lungs was decreased by p50 deficiency, to approximately 30% of wild type levels. Heat-killed E. coli induced neutrophil accumulation which was not decreased by p50 deficiency, demonstrating that bacterial growth and metabolism were not responsible for the different responses to bacteria and LPS. p50 deficiency increased the LPS-induced expression of κB-regulated genes essential to neutrophil recruitment, including KC, MIP-2, ICAM-1, and TNF-α suggesting that p50 normally limited this gene expression and that decreased neutrophil recruitment did not result from insufficient expression of these genes. Neutrophils were responsive to the chemokine KC in the peripheral blood of p50-deficient mice with or without LPS-induced pulmonary inflammation. Interleukin-6 (IL-6), previously demonstrated to decrease LPS-induced neutrophil recruitment in the lungs, was increased by p50 deficiency, but LPS-induced neutrophil recruitment was decreased by p50 deficiency even in IL-6 deficient mice. CONCLUSION: p50 makes essential contributions to neutrophil accumulation elicited by LPS in the lungs. This p50-dependent pathway for neutrophil accumulation can be overcome by bacterial products other than LPS and does not require IL-6

Chronic treatment with long-acting nifedipine reduces vasoconstriction to endothelin-1 in essential hypertension

Essential hypertension is associated with enhanced biological activity of endothelin-1 (ET-1) and impaired endothelium-dependent vasodilatation. Dihydropyridine calcium antagonists have antioxidant activity in vitro, and they improve endothelial function in vivo. We tested whether calcium antagonists also influence the biological activity of ET-1 in essential hypertensive (EH) patients in the presence and absence of hypercholesterolemia. In 9 healthy subjects (normotensive [NT] subjects, age: 48.3+/-7.6 years; blood pressure: 118+/-8.6/69+/-5.4 mm Hg) and 21 EH subjects (age: 50.0+/-7.8 years; blood pressure: 164.4+/-5.4/103.8+/-4.4 mm Hg), we studied forearm blood flow and its modification induced by intrabrachial administration of ET-1, phenylephrine, acetylcholine, and sodium nitroprusside at baseline and after 24 weeks of treatment with a nifedipine gastrointestinal therapeutic system (30 to 60 mg per day). At baseline, the first dose of ET-1 (0.5 microg/100 mL of forearm tissue per minute) caused a slight vasodilatation in NT but not in EH subjects, whereas the following higher doses caused a comparable dose-dependent vasoconstriction in EH and NT subjects. The effect of acetylcholine was significantly reduced in EH as compared with NT subjects. In contrast, sodium nitroprusside and phenylephrine had similar effects in NT and EH subjects. After chronic treatment with the nifedipine gastrointestinal therapeutic system, the vasoconstrictor effect induced by both ET-1 and phenylephrine was significantly blunted, whereas the response to acetylcholine was significantly increased and the vasodilation to sodium nitroprusside unchanged. Hypercholesterolemic EH subjects showed a further reduced response to acetylcholine compared with normocholesterolemic EH subjects, and the nifedipine gastrointestinal therapeutic system restored the vasodilation to acetylcholine in this subgroup. In conclusion, in EH subjects, chronic treatment with a long-acting dihydropyridine calcium antagonist not only exhibits a blood pressure-lowering effect but also reduces ET-1-induced vasoconstriction and improves endothelium-dependent vasodilation. Those vasculoprotective effects may importantly contribute to a reduction in major clinical events seen during treatment with these compound

Octupole correlations in positive-parity states of rare-earth and actinide nuclei

In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t) experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite J(pi) = 0(+) states in Pu-240. spd f interacting boson model (IBM) calculations suggest that the previously proposed double-octupole phonon nature of the J(pi) = 0(2)(+) state is not in conflict with its strong (p, t) population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positive- and negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (J(pi) = 10(+)) leading to the change in yrast structure observed in Nd-146

Octupole correlations in positive-parity states of rare-earth and actinide nuclei

In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t) experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite J(pi) = 0(+) states in Pu-240. spd f interacting boson model (IBM) calculations suggest that the previously proposed double-octupole phonon nature of the J(pi) = 0(2)(+) state is not in conflict with its strong (p, t) population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positive- and negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (J(pi) = 10(+)) leading to the change in yrast structure observed in Nd-146