A proposal for an experimental realization of Bohm s spin-2 particle version of the Einstein-Podolsky-Rosen experiment is described. Two ' Hg atoms, each with nuclear spin 2, are produced in an entangled state with total nuclear spin zero. Such a state is obtained by dissociation of dimers of the ' Hg2 isotopomer using a spectroscopically selective stimulated Raman process. The measurement of nuclear spin correlations between the two atoms in this entangled state is achieved by detection of the atoms using a spin state selective two-photon excitation-ionization scheme. The experiment will not only close the detector efficiency loophole, but in addition will permit enforcement of the locality condition. PACS number(s): 03.65.8z; 32.80.Fb 'Reference [18]. Reference [19]. 'Calculated from the separated atom (P, + 'So) limit and the values of D,. Calculated from r,(1"). 'Calculated from B6o = B,-60.5a, .
Optical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements and theoretical modelling can be performed to high precision, taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production, which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition SP. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work.
One of the unsolved problems of dynamics in supercooled liquids are the differences in spectral shape of the structural relaxation observed among different methods and substances, and a possible generic line shape has long been debated. We show that the light scattering spectra of very different systems, e.g., hydrogen bonding, van der Waals liquids, and ionic systems, almost perfectly superimpose and show a generic line shape of the structural relaxation, following ∝ ω–1/2 at high frequencies. In dielectric spectra the generic behavior is recovered only for systems with low dipole moment, while in strongly dipolar liquids additional cross-correlation contributions mask the generic structural relaxation.
Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of ^{252,253,254}No, and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton density distribution in ^{252,254}No isotopes. Finally, the hyperfine splitting of ^{253}No was evaluated, enabling a complementary measure of its (quadrupole) deformation, as well as an insight into the neutron single-particle wave function via the nuclear spin and magnetic moment.
Microneedle-based microfluidic systems have a great potential to become well-accepted medical devices for simple, accurate, and painless drug delivery and lab-on-a-chip diagnostics. In this work, we report on a novel hybrid approach combining femtosecond direct laser written microneedles with femtosecond laser generated microfluidic channels providing an important step towards versatile medical point-of-care systems. Hollow microneedle arrays are fabricated by a laser system designed for two-photon polymerization applications. Compression tests of two different types of truncated cone-shaped microneedle arrays prepared from OrmoComp® give information about the microneedle mechanical strength, and the results are compared to skin insertion forces. Three-dimensional microchannels are directly created inside PMMA bulk material by an ultrashort pulse laser system with vertical channels having adjustable cross-sectional areas, which allow attaching of microneedles to the microfluidic system. A comprehensive parameter study varying pulse duration and repetition rate is performed on two-photon polymerization to identify an optimal laser power range for fabricating microneedles using the same pulse duration and repetition rate as for microchannels. This addresses the advantage of a single laser system process that overcomes complex fabrication methods. A proof of concept flow test with a rhodamine B dye solution in distilled water demonstrates that the combination of microneedles and microchannels qualifies for microfluidic injection and extraction applications.
The synchronous application of narrowband UVB phototherapy with 311 nm lamps (Philips TL-01) and bathing in Dead Sea salt solution was evaluated in a multicentre trial (n = 60) in outpatients suffering from psoriasis vulgaris. The study design consisted of an initial therapy phase of up to 35 treatments (three to five times a week) followed by maintenance therapy with up to 35 further applications (once or twice a week). Evaluation was performed separately for patients in according-to-protocol (ATP) (n = 280) and intention-to-treat (ITT) (n = 692) groups. An overall significant improvement of the Psoriasis Area and Severity Index (PASI) score (P < 0.05) could be shown for both groups during initial therapy with 71.4% improvement for ATP and 61% for ITT patients. The mean PASI for ATP (values for ITT in parentheses) was 17.7 (18.6) at baseline, 9.5 (10.7) after 20 applications and 5.2 (7.4) at the end of initial therapy. On average, ATP patients received 3.9 (3.5) applications per week with a cumulative irradiation dose of 19.5 J cm-2 (16.2 J cm-2). The most frequent side-effect was erythema, observed in 8.7% of the patients. Subjective evaluation of the therapy by the patients (n = 168) was excellent. Seventy-nine per cent of patients preferred the new treatment strategy in comparison with other previous therapies and 88% regarded this therapy as pleasant and comfortable. In conclusion, we could demonstrate a significant effect of therapy in both the ATP and the ITT groups for this new treatment system which imitates, as far as possible, the Dead Sea climatic conditions, with no severe side-effects and a high acceptance by the patients.
One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21±0.000 05 eV. This work provides a stringent benchmark for state-of-the-art many-body atomic modeling that considers relativistic and quantum electrodynamic effects and paves the way for high-precision measurements of atomic properties of elements only available from heavy-ion accelerator facilities.
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