Spectral shaping of laser generated proton beams

The rapid progress in the field of laser particle acceleration has stimulated a debate about the promising perspectives of laser based ion beam sources. For a long time, the beams produced exhibited quasi-thermal spectra. Recent proof-of-principle experiments demonstrated that ion beams with narrow energy distribution can be generated from special target geometries. However, the achieved spectra were strongly limited in terms of monochromacity and reproducibility. We show that microstructured targets can be used to reliably produce protons with monoenergetic spectra above 2 MeV with less than 10% energy spread. Detailed investigations of the effects of laser ablation on the target resulted in a significant improvement of the reproducibility. Based on statistical analysis, we derive a scaling law between proton peak position and laser energy, underlining the suitability of this method for future applications. Both the quality of the spectra and the scaling law are well reproduced by numerical simulations

Observation of energetic terahertz pulses from relativistic solid density plasmas

We report the first experimental observation of terahertz (THz) radiation from the rear surface of a solid target while interacting with an intense laser pulse. Experimental and two-dimensional particle-in-cell simulations show that the observed THz radiation is mostly emitted at large angles to the target normal. Numerical results point out that a large part of the emission originates from a micron-scale plasma sheath at the rear surface of the target, which is also responsible for the ion acceleration. This opens a perspective for the application of THz radiation detection for on-site diagnostics of particle acceleration in laser-produced plasmas

Triple F - a comet nucleus sample return mission

The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. The proposed mission would extract three sample cores of the upper 50cm from three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-and-go sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS. © The Author(s) 2008

Thermodynamic Additivity of Sequence Variations: An Algorithm for Creating High Affinity Peptides Without Large Libraries or Structural Information

BACKGROUND: There is a significant need for affinity reagents with high target affinity/specificity that can be developed rapidly and inexpensively. Existing affinity reagent development approaches, including protein mutagenesis, directed evolution, and fragment-based design utilize large libraries and/or require structural information thereby adding time and expense. Until now, no systematic approach to affinity reagent development existed that could produce nanomolar affinity from small chemically synthesized peptide libraries without the aid of structural information. METHODOLOGY/PRINCIPAL FINDINGS: Based on the principle of additivity, we have developed an algorithm for generating high affinity peptide ligands. In this algorithm, point-variations in a lead sequence are screened and combined in a systematic manner to achieve additive binding energies. To demonstrate this approach, low-affinity lead peptides for multiple protein targets were identified from sparse random sequence space and optimized to high affinity in just two chemical steps. In one example, a TNF-α binding peptide with K(d) = 90 nM and high target specificity was generated. The changes in binding energy associated with each variation were generally additive upon combining variations, validating the basis of the algorithm. Interestingly, cooperativity between point-variations was not observed, and in a few specific cases, combinations were less than energetically additive. CONCLUSIONS/SIGNIFICANCE: By using this additivity algorithm, peptide ligands with high affinity for protein targets were generated. With this algorithm, one of the highest affinity TNF-α binding peptides reported to date was produced. Most importantly, high affinity was achieved from small, chemically-synthesized libraries without the need for structural information at any time during the process. This is significantly different than protein mutagenesis, directed evolution, or fragment-based design approaches, which rely on large libraries and/or structural guidance. With this algorithm, high affinity/specificity peptide ligands can be developed rapidly, inexpensively, and in an entirely chemical manner

A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain

Low back pain (LBP) is a common and disabling disorder in western society. The management of LBP comprises a range of different intervention strategies including surgery, drug therapy, and non-medical interventions. The objective of the present study is to determine the effectiveness of physical and rehabilitation interventions (i.e. exercise therapy, back school, transcutaneous electrical nerve stimulation (TENS), low level laser therapy, education, massage, behavioural treatment, traction, multidisciplinary treatment, lumbar supports, and heat/cold therapy) for chronic LBP. The primary search was conducted in MEDLINE, EMBASE, CINAHL, CENTRAL, and PEDro up to 22 December 2008. Existing Cochrane reviews for the individual interventions were screened for studies fulfilling the inclusion criteria. The search strategy outlined by the Cochrane Back Review Groups (CBRG) was followed. The following were included for selection criteria: (1) randomized controlled trials, (2) adult (≥18 years) population with chronic (≥12 weeks) non-specific LBP, and (3) evaluation of at least one of the main clinically relevant outcome measures (pain, functional status, perceived recovery, or return to work). Two reviewers independently selected studies and extracted data on study characteristics, risk of bias, and outcomes at short, intermediate, and long-term follow-up. The GRADE approach was used to determine the quality of evidence. In total 83 randomized controlled trials met the inclusion criteria: exercise therapy (n = 37), back school (n = 5), TENS (n = 6), low level laser therapy (n = 3), behavioural treatment (n = 21), patient education (n = 1), traction (n = 1), and multidisciplinary treatment (n = 6). Compared to usual care, exercise therapy improved post-treatment pain intensity and disability, and long-term function. Behavioural treatment was found to be effective in reducing pain intensity at short-term follow-up compared to no treatment/waiting list controls. Finally, multidisciplinary treatment was found to reduce pain intensity and disability at short-term follow-up compared to no treatment/waiting list controls. Overall, the level of evidence was low. Evidence from randomized controlled trials demonstrates that there is low quality evidence for the effectiveness of exercise therapy compared to usual care, there is low evidence for the effectiveness of behavioural therapy compared to no treatment and there is moderate evidence for the effectiveness of a multidisciplinary treatment compared to no treatment and other active treatments at reducing pain at short-term in the treatment of chronic low back pain. Based on the heterogeneity of the populations, interventions, and comparison groups, we conclude that there are insufficient data to draw firm conclusion on the clinical effect of back schools, low-level laser therapy, patient education, massage, traction, superficial heat/cold, and lumbar supports for chronic LBP