Bio-inspired band-gap tunable elastic optical multilayer fibers.

The concentrically-layered photonic structure found in the tropical fruit Margaritaria nobilis serves as inspiration for photonic fibers with mechanically tunable band-gap. The fibers show the spectral filtering capabilities of a planar Bragg stack while the microscopic curvature decreases the strong directional chromaticity associated with flat multilayers. Elongation of the elastic fibers results in a shift of the reflection of over 200 nm.Financial support from the US Air Force Offi ce of Scientifi c Research Multidisciplinary University Research Initiative under award numbers FA9550-09-1-0669-DOD35CAP, FA9550-10-1-0020 and the UK Engineering and Physical Sciences Research Council EP/G060649/1 is gratefully acknowledged. M.Ko. acknowledges the fi nancial support from the Alexander von Humboldt Foundation in form of a Feodor Lynen postdoctoral research fellowship. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765. CNS is part of Harvard University

Structures of the eukaryotic ribosome and its translational states in situ

Ribosomes translate genetic information into primary structure. During translation, various cofactors transiently bind to the ribosome that undergoes prominent conformational and structural changes. Different translational states of ribosomes have been well characterized in vitro. However, to which extent the known translational states are representative of the native situation inside cells has thus far only been addressed in prokaryotes. Here, we apply cryo-electron tomography to cryo-FIB milled Dictyostelium discoideum cells combined with subtomogram averaging and classification. We obtain an in situ structure that is locally resolved up to 3 Angstrom, the distribution of eukaryotic ribosome translational states, and unique arrangement of rRNA expansion segments. Our work demonstrates the use of in situ structural biology techniques for identifying distinct ribosome states within the cellular environment

Endocrine hormone imbalance in heart failure with reduced ejection fraction: A cross-sectional study

BACKGROUND AND AIMS Sustained neurohormonal activation plays a central role in the progression of heart failure (HF). Other endocrine axes may also be affected. It was the aim of this study to examine the endocrine profile (thyroid, parathyroid, glucocorticoid, and sex hormones) in a contemporary sample of patients with HF and reduced ejection fraction (EF) on established disease-modifying therapy. METHODS This study prospectively measured morning fasting hormones in 52 ambulatory and stable HF patients with EF < 50% on disease-modifying therapy (mean age 63 ± 11 years, 29% female, mean LVEF 32 ± 9.6%) and compared them to 54 patients at elevated risk for HF (61 ± 12 years, 28% female) and 62 healthy controls (HC; 61 ± 13 years, 27% female). Main comparisons were performed using one-way analysis of variance. Associations with biomarkers were studied with linear regression. RESULTS HF patients showed a reduced free triiodothyronine (fT3)/free thyroxine (fT4) ratio compared to HC (0.30 ± 0.06 vs. 0.33 ± 0.05, p = 0.046). Parathyroid hormone (PTH) and cortisol were increased in HF compared to both HC (median [IQR] 59 [50-84] vs. 46 [37-52] ng/L, p < 0.001 and 497 ± 150 vs. 436 ± 108 nmol/L, p = 0.03, respectively) and patients at risk (both p < 0.001). Total testosterone was reduced in male HF compared to HC (14.4 ± 6.6 vs. 18.6 ± 5.3 nmol/L; p = 0.01). No differences in TSH, estradiol, progesterone, and prolactin were found. Lower fT3 levels were found in HF with EF < 40% versus EF 40%-49% (4.6 ± 0.3 vs. 5.2 ± 0.7 pmol/L, p = 0.009). In HF patients, fT3 was an independent predictor of NT-proBNP and high-sensitivity troponin T in multiple regression analysis. PTH was positively associated with NT-proBNP. CONCLUSION There is evidence of endocrine hormonal imbalance in HF with reduced EF beyond principal neurohormones and despite the use of disease-modifying therapy

51 Eri and GJ 3305: A 10-15 Myr old binary star system at 30 parsecs

Following the suggestion of Zuckerman et al. (2001, ApJ, 562, L87), we consider the evidence that 51 Eri (spectral type F0) and GJ 3305 (M0), historically classified as unrelated main sequence stars in the solar neighborhood, are instead a wide physical binary system and members of the young beta Pic moving group (BPMG). The BPMG is the nearest (d < 50 pc) of several groups of young stars with ages around 10 Myr that are kinematically convergent with the Oph-Sco-Cen Association (OSCA), the nearest OB star association. Combining SAAO optical photometry, Hobby-Eberly Telescope high-resolution spectroscopy, Chandra X-ray data, and UCAC2 catalog kinematics, we confirm with high confidence that the system is indeed extremely young. GJ 3305 itself exhibits very strong magnetic activity but has rapidly depleted most of its lithium. The 51 Eri/GJ 3305 system is the westernmost known member of the OSCA, lying 110 pc from the main subgroups. The system is similar to the BPMG wide binary HD 172555/CD -64d1208 and the HD 104237 quintet, suggesting that dynamically fragile multiple systems can survive the turbulent environments of their natal giant molecular cloud complexes, while still being imparted high dispersion velocities. Nearby young systems such as these are excellent targets for evolved circumstellar disk and planetary studies, having stellar ages comparable to that of the late phases of planet formation.Comment: 27 pages, 7 figures. Accepted for publication in the Astronomical Journal. For a version with high resolution figures, see http://www.astro.psu.edu/users/edf/51Eri.pd

ROSAT observations of X-ray emission from planetary nebulae

We have searched the entire ROSAT archive for useful observations to study X-ray emission from Galactic planetary nebulae (PNs). The search yields a sample of 63 PNs, which we call the ROSAT PN sample. About 20-25% of this sample show X-ray emission; these include 13 definite detections and three possible detections (at a 2-sigma level). All X-ray sources in these PNs are concentrated near the central stars. Only A 30, BD+30 3639, and NGC 6543 are marginally resolved by the ROSAT instruments. Three types of X-ray spectra are seen in PNs. Type 1 consists of only soft X-ray emission (<0.5 keV), peaks at 0.1-0.2 keV, and can be fitted by blackbody models at temperatures 1-2 10^5 K. Type 2 consists of harder X-ray emission, peaks at >0.5 keV, and can be fitted by thin plasma emission models at temperatures of a few 10^6 K. Type 3 is a composite of a bright Type 1 component and a fainter Type 2 component. Unresolved soft sources with Type 1 spectra or the soft component of Type 3 spectra are most likely photospheric emission from the hot central stars. Absorption cross sections are large for these soft-energy photons; therefore, only large, tenuous, evolved PNs with hot central stars and small absorption column densities have been detected. The origin of hard X-ray emission from PNs is uncertain. PNs with Type 2 spectra are small, dense, young nebulae with relatively cool (<<10^5 K) central stars, while PNs with Type 3 X-ray spectra are large, tenuous, evolved nebulae with hot central stars. The hard X-ray luminosities are also different between these two types of PNs, indicating perhaps different origins of their hard X-ray emission. Future Chandra and XMM observations with high spatial and spectral resolution will help to understand the origin of hard X-ray emission from PNs.Comment: To be published in The Astrophysical Journal Supplement Series. 21 pages, 7 figures, 5 table

Three-dimensional holographic optical manipulation through a high-numerical-aperture soft-glass multimode fibre

Holographic optical tweezers (HOT) hold great promise for many applications in biophotonics, allowing the creation and measurement of minuscule forces on biomolecules, molecular motors and cells. Geometries used in HOT currently rely on bulk optics, and their exploitation in vivo is compromised by the optically turbid nature of tissues. We present an alternative HOT approach in which multiple three-dimensional (3D) traps are introduced through a high-numerical-aperture multimode optical fibre, thus enabling an equally versatile means of manipulation through channels having cross-section comparable to the size of a single cell. Our work demonstrates real-time manipulation of 3D arrangements of micro-objects, as well as manipulation inside otherwise inaccessible cavities. We show that the traps can be formed over fibre lengths exceeding 100 mm and positioned with nanometric resolution. The results provide the basis for holographic manipulation and other high-numerical-aperture techniques, including advanced microscopy, through single-core-fibre endoscopes deep inside living tissues and other complex environments

2MASS J0516288+260738: Discovery of the first eclipsing late K + Brown dwarf binary system

Original article available at: http://www.aanda.org/--Copyright The European Southern Observatory DOI : 10.1051/0004-6361:20031241We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV05134+2605. The object could be identified with the point source 2MASSJ0516288+260738 published by the Two Micron All Sky Survey.We present and discuss the first light curves as well as some additional colour and spectral information. The eclipse period of the system is 1.29 d, and, assuming this to be identical to the orbital period, the best light curve solution yields a mass ratio of m2/m1 = 0.11, a radius ratio of r2/r1 ≈ 1 and an inclination of 74◦. The spectral anaylsis results in a Teff = 4200 K for the primary. On this basis, we suggest that the new system probably consists of a late K + Brown dwarf (which would imply a system considerably younger than ≈0.01 Gyr to have r2/r1 ≈ 1), and outline possible future observations.Peer reviewe

Endocrine hormone imbalance in heart failure with reduced ejection fraction: A cross‐sectional study

Abstract Background and Aims Sustained neurohormonal activation plays a central role in the progression of heart failure (HF). Other endocrine axes may also be affected. It was the aim of this study to examine the endocrine profile (thyroid, parathyroid, glucocorticoid, and sex hormones) in a contemporary sample of patients with HF and reduced ejection fraction (EF) on established disease‐modifying therapy. Methods This study prospectively measured morning fasting hormones in 52 ambulatory and stable HF patients with EF < 50% on disease‐modifying therapy (mean age 63 ± 11 years, 29% female, mean LVEF 32 ± 9.6%) and compared them to 54 patients at elevated risk for HF (61 ± 12 years, 28% female) and 62 healthy controls (HC; 61 ± 13 years, 27% female). Main comparisons were performed using one‐way analysis of variance. Associations with biomarkers were studied with linear regression. Results HF patients showed a reduced free triiodothyronine (fT3)/free thyroxine (fT4) ratio compared to HC (0.30 ± 0.06 vs. 0.33 ± 0.05, p = 0.046). Parathyroid hormone (PTH) and cortisol were increased in HF compared to both HC (median [IQR] 59 [50–84] vs. 46 [37–52] ng/L, p < 0.001 and 497 ± 150 vs. 436 ± 108 nmol/L, p = 0.03, respectively) and patients at risk (both p < 0.001). Total testosterone was reduced in male HF compared to HC (14.4 ± 6.6 vs. 18.6 ± 5.3 nmol/L; p = 0.01). No differences in TSH, estradiol, progesterone, and prolactin were found. Lower fT3 levels were found in HF with EF < 40% versus EF 40%–49% (4.6 ± 0.3 vs. 5.2 ± 0.7 pmol/L, p = 0.009). In HF patients, fT3 was an independent predictor of NT‐proBNP and high‐sensitivity troponin T in multiple regression analysis. PTH was positively associated with NT‐proBNP. Conclusion There is evidence of endocrine hormonal imbalance in HF with reduced EF beyond principal neurohormones and despite the use of disease‐modifying therapy