Coherent Control of the Exciton Dynamics in the FMO Protein

We have achieved first steps toward coherent control of excitonic energy migration in the FMO pigment-protein complex, by combining femtosecond pulse shaping with a feedback loop using an evolutionary algorithm. The experimental conditions achieved, with a rotating sample, a cryostat, and a pulse shaper, are sufficient for closed loop optimizations.</p

CRISPR/cas Loci of Type II Propionibacterium acnes Confer Immunity against Acquisition of Mobile Elements Present in Type I P. acnes

Propionibacterium acnes is a skin commensal that occasionally acts as an opportunistic pathogen. The population structure of this species shows three main lineages (I–III). While type I strains are mainly associated with sebaceous follicles of human skin and inflammatory acne, types II and III strains are more often associated with deep tissue infections. We investigated the occurrence and distribution of the clustered regularly interspaced short palindromic repeats (CRISPR) in P. acnes, assessed their immunological memory, and addressed the question if such a system could account for type-specific properties of the species. A collection of 108 clinical isolates covering all known phylotypes of P. acnes was screened for the existence of CRISPR/cas loci. We found that CRISPR loci are restricted to type II P. acnes strains. Sequence analyses of the CRISPR spacers revealed that the system confers immunity to P. acnes-specific phages and to two mobile genetic elements. These elements are found almost exclusively in type I P. acnes strains. Genome sequencing of a type I P. acnes isolate revealed that one element, 54 kb in size, encodes a putative secretion/tight adherence (TAD) system. Thus, CRISPR/cas loci in P. acnes recorded the exposure of type II strains to mobile genetic elements of type I strains. The CRISPR/cas locus is deleted in type I strains, which conceivably accounts for their ability to horizontally acquire fitness or virulence traits and might indicate that type I strains constitute a younger subpopulation of P. acnes

THE EFFECT OF DIFFERENT FOOTWEAR ON THE MYOELECTRIC ACTIVITY OF M. TIBIALIS POSTERIOR DURING TREADMILL RUNNING

Overload running injuries of the lower extremity, particularly the knee, are associated with excessive pronation of the foot resulting in tibial rotation (Nigg et al., 1995). M. tibialis posterior (TP) is shown to have an active influence on pronation and the medial longitudinal arch (Kaye & Jahss, 1991). Its functional role during running and interaction with footwear is still not clearly understood (Reber et al., 1993; O’Connor & Hamill, 2004). Therefore the purpose of this study is to investigate the influence of different footwear on the muscle’s EMG pattern

WIRE EMG OF FLEXOR HALLUCIS LONGUS DURING BAREFOOT AND SHOD RUNNING ON A TREADMILL: A PILOT STUDY

Excessive pronation is associated with overload injuries of the lower extremity (Nigg, 1995). The flexor hallucis longus (FHL) acts against the pronation of the calcaneus (Klein, 1996). The influence of different footwear on the activity of the FHL was neither measured in walking nor running. The purpose of this study was to investigate the activity of the FHL during different phases in stance of walking and running in different footwear conditions

Propionibacterium acnes inhibits FOXM1 and induces cell cycle alterations in human primary prostate cells

AbstractPropionibacterium acnes has been detected in diseased human prostate tissue, and cell culture experiments suggest that the bacterium can establish a low-grade inflammation. Here, we investigated its impact on human primary prostate epithelial cells. Microarray analysis confirmed the inflammation-inducing capability of P. acnes but also showed deregulation of genes involved in the cell cycle. qPCR experiments showed that viable P. acnes downregulates a master regulator of cell cycle progression, FOXM1. Flow cytometry experiments revealed that P. acnes increases the number of cells in S-phase. We tested the hypothesis that a P. acnes-produced berninamycin-like thiopeptide is responsible for this effect, since it is related to the FOXM1 inhibitor siomycin. The thiopeptide biosynthesis gene cluster was strongly expressed; it is present in subtype IB of P. acnes, but absent from type IA, which is most abundant on human skin. A knock-out mutant lacking the gene encoding the berninamycin-like peptide precursor was unable to downregulate FOXM1 and to halt the cell cycle. Our study reveals a novel host cell-interacting activity of P. acnes

KINEMATIC PROFILE OF THE ELITE HANDCYCLIST

A handcycle is a relatively new sports equipment that is a combination of the traditional race wheelchair and a hand operated bicycle crank (Abel, Schneider, Platen, & Struder, 2006). The high mechanical efficiency of this geared fixed-frame racing cycle in comparison to a manual wheelchair can potentially increase the distance a person with a loss of lower limb function can travel. To guide the optimal setup for the handcyclist the influence of crank length (Goosey-Tolfrey, Alfano, & Fowler, 2008; Kramer, Hilker, & Bohm, 2009) and crank configuration (Faupin, Gorce, Meyer, & Thevenon, 2008a; Mossberg, Willman, Topor, Crook, & Patak, 1999) have been investigated. Actual neither research has been done on the upper body kinematics of elite athletes nor on relations between kinematics and performance. The aim of this study was to provide first sport specific information in this area with regards to athletes competing at an international level

Ocean variability and its influence on the detectability of greenhouse warming signals

Recent investigations have considered whether it is possible to achieve early detection of greenhouse-gas-induced climate change by observing changes in ocean variables. In this study we use model data to assess some of the uncertainties involved in estimating when we could expect to detect ocean greenhouse warming signals. We distinguish between detection periods and detection times. As defined here, detection period is the length of a climate time series required in order to detect, at some prescribed significance level, a given linear trend in the presence of the natural climate variability. Detection period is defined in model years and is independent of reference time and the real time evolution of the signal. Detection time is computed for an actual time-evolving signal from a greenhouse warming experiment and depends on the experiment's start date. Two sources of uncertainty are considered: those associated with the level of natural variability or noise, and those associated with the time-evolving signals. We analyze the ocean signal and noise for spatially averaged ocean circulation indices such as heat and fresh water fluxes, rate of deep water formation, salinity, temperature, transport of mass, and ice volume. The signals for these quantities are taken from recent time-dependent greenhouse warming experiments performed by the Max Planck Institute for Meteorology in Hamburg with a coupled ocean-atmosphere general circulation model. The time-dependent greenhouse gas increase in these experiments was specified in accordance with scenario A of the Intergovernmental Panel on Climate Change. The natural variability noise is derived from a 300-year control run performed with the same coupled atmosphere-ocean model and from two long (>3000 years) stochastic forcing experiments in which an uncoupled ocean model was forced by white noise surface flux variations. In the first experiment the stochastic forcing was restricted to the fresh water fluxes, while in the second experiment the ocean model was additionally forced by variations in wind stress and heat fluxes. The mean states and ocean variability are very different in the three natural variability integrations. A suite of greenhouse warming simulations with identical forcing but different initial conditions reveals that the signal estimated from these experiments may evolve in noticeably different ways for some ocean variables. The combined signal and noise uncertainties translate into large uncertainties in estimates of detection time. Nevertheless, we find that ocean variables that are highly sensitive indicators of surface conditions, such as convective overturning in the North Atlantic, have shorter signal detection times (35?65 years) than deep-ocean indicators (≥100 years). We investigate also whether the use of a multivariate detection vector increases the probability of early detection. We find that this can yield detection times of 35?60 years (relative to a 1985 reference date) if signal and noise are projected onto a common ?fingerprint? which describes the expected signal direction. Optimization of the signal-to-noise ratio by (spatial) rotation of the fingerprint in the direction of low-noise components of the stochastic forcing experiments noticeably reduces the detection time (to 10?45 years). However, rotation in space alone does not guarantee an improvement of the signal-to-noise ratio for a time-dependent signal. This requires an ?optimal fingerprint? strategy in which the detection pattern (fingerprint) is rotated in both space and time

Modulation of a surface plasmon-polariton resonance by sub-terahertz diffracted coherent phonons

Coherent sub-THz phonons incident on a gold grating that is deposited on a dielectric substrate undergo diffraction and thereby induce an alteration of the surface plasmon-polariton resonance. This results in efficient high-frequency modulation (up to 110 GHz) of the structure's reflectivity for visible light in the vicinity of the plasmon-polariton resonance. High modulation efficiency is achieved by designing a periodic nanostructure which provides both plasmon-polariton and phonon resonances. Our theoretical analysis shows that the dynamical alteration of the plasmon-polariton resonance is governed by modulation of the slit widths within the grating at the frequencies of higher-order phonon resonances.Comment: 5 pages, 4 figure

Hygroscopic growth of urban aerosol particles in Beijing (China) during wintertime: A comparison of three experimental methods

The hygroscopic properties of atmospheric aerosols are highly relevant for the quantification of radiative effects in the atmosphere, but also of interest for the assessment of particle health effects upon inhalation. This article reports measurements of aerosol particle hygroscopicity in the highly polluted urban atmosphere of Beijing, China in January 2005. The meteorological conditions corresponded to a relatively cold and dry atmosphere. Three different methods were used: 1) A combination of Humidifying Differential Mobility Particle Sizer (H-DMPS) and Twin Differential Mobility Particle Sizer (TDMPS) measurements, 2) A Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), and 3) A simplistic solubility model fed by chemical particle composition determined from Micro Orifice Uniform Deposit Impactor (MOUDI) samples. From the H-DMPS and TDMPS particle number size distributions, a size-resolved descriptive hygroscopic growth factor (DHGF) was determined for the relative humidities (RH) 55%, 77% and 90%, and particle diameters between 30 and 400 nm. In Beijing, the highest DHGFs were observed for accumulation mode particles, 1.40 (±0.03) at 90% RH. DHGF decreased significantly with particle size, reaching 1.04 (±0.15) at 30 nm. H-TDMA data also suggest a decrease in growth factor towards the biggest particles investigated (350 nm), associated with an increasing fraction of nearly hydrophobic particles. The agreement between the H-DMPS/TDMPS and H-TDMA methods was satisfactory in the accumulation mode size range (100–400 nm). In the Aitken mode range (<100 nm), the H-DMPS/TDMPS method yielded growth factors lower by up to 0.1 at 90% RH. The application of the solubility model based on measured chemical composition clearly reproduced the size-dependent trend in hygroscopic particle growth observed by the other methods. In the case of aerosol dominated by inorganic ions, the composition-derived growth factors tended to agree (± 0.05) or underestimate (up to 0.1) the values measured by the other two methods. In the case of aerosol dominated by organics, the reverse was true, with an overestimation of up to 0.2. The results shed light on the experimental and methodological uncertainties that are still connected with the determination of hygroscopic growth factors