An imaging technique lets scientists peer through the skin of a whole mouse or rat to examine its organs after death. Ali Ertürk of the Ludwig Maximilians University of Munich in Germany and his colleagues created a technique called ultimate DISCO (uDISCO), which removes pigments and lipids from the tissues of dead animals using an organic solvent. This leaves the organs and skin intact but transparent, while preserving genetically encoded fluorescent proteins. The method revealed the nervous system of a mouse in stark detail. uDISCO also shrinks bodies by up to 65%, making it possible to image whole animals using light-sheet microscopy, which excels at imaging smaller samples. Nature Methods http://dx.
We present an interferometric displacement sensor based on a folded low-finesse Fabry-Perot cavity. The fiber-optic sensor uses a quadrature detection scheme based on the wavelength modulation of a DFB laser. This enables measuring position changes over a range of 1 m for velocities up to 2 m/s. The sensor is well suited to work in extreme environments such as ultrahigh vacuum, cryogenic temperatures, or high magnetic fields and supports multichannel applications. The interferometer achieves a repeatability of 0.44 nm(3σ) at a working distance of 20 mm, a resolution of 1 pm, and an accuracy of 1 nm.
We report on state-of-the-art scanning probe microscopy measurements performed in a pulse tube based top-loading closed-cycle cryostat with a base temperature of 4 K and a 9 T magnet. We decoupled the sample space from the mechanical and acoustic noise from the cryocooling system to enable scanning probe experiments. The extremely low vibration amplitudes in our system enabled successful imaging of 0.39 nm lattice steps on single crystalline SrTiO 3 as well as magnetic vortices in Bi 2 Sr 2 CaCu 2 O 8+x superconductor. Fine control over sample temperature and applied magnetic field further enabled us to probe the helimagnetic and the skyrmion-lattice phases in Fe 0.5 Co 0.5 Si with unprecedented signal-to-noise ratio of 20:1. Finally, we demonstrate for the first time quartz-crystal tuning fork shear-force microscopy in a closed-cycle cryostat. arXiv:1404.2046v1 [cond-mat.mtrl-sci]
We have fabricated and characterised the optical properties of solution processed randomly distributed gold nanoparticle plasmonic arrays that are coated with a thin-film fluorescent dye. Three times enhancement in the emission intensity of the fluorescent dye Pyridine 2 has been observed. Our results are further supported by finite difference time domain simulations that predicted up to 7 times enhancements in the emission intensity as a result of the coupling between the molecular dipoles and the confined field in the underlying plasmonic array. Our results demonstrate the potential of using such structures in organic light emitting devices and chemical and bio-sensing applications.
As a novel organic solvent-based tissue clearing method, the uDISCO technique maintains the feature of tissue shrinkage while overcomes the fast signal quenching and preserves the endogenous fluorescence over months. By rendering the intact organs and rodent bodies transparent while reducing their size up to 65%, uDISCO enables the light-sheet microscopy of entire body of adult mice with subcellular resolution for the first time. Additionally, uDISCO is compatible with virus tracing, antibody labeling and over-fixed human tissue staining allowing the usage in various biomedical applications. Here, we provide a detailed protocol of uDISCO describing the preparation of samples and solutions, procedure of passive clearing and whole-body clearing with perfusion system. The whole procedure takes from 2 days to 1 week depending on the tissue size.
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