2,242 research outputs found
Controlling the sense of molecular rotation
We introduce a new scheme for controlling the sense of molecular rotation. By
varying the polarization and the delay between two ultrashort laser pulses, we
induce unidirectional molecular rotation, thereby forcing the molecules to
rotate clockwise/counterclockwise under field-free conditions. We show that
unidirectionally rotating molecules are confined to the plane defined by the
two polarization vectors of the pulses, which leads to a permanent anisotropy
in the molecular angular distribution. The latter may be useful for controlling
collisional cross-sections and optical and kinetic processes in molecular
gases. We discuss the application of this control scheme to individual
components within a molecular mixture in a selective manner.Comment: 21 pages, 10 figures, Submitted to the New Journal of Physics for the
"coherent control" special issu
2s Hyperfine Structure in Hydrogen Atom and Helium-3 Ion
The usefulness of study of hyperfine splitting in the hydrogen atom is
limited on a level of 10 ppm by our knowledge of the proton structure. One way
to go beyond 10 ppm is to study a specific difference of the hyperfine
structure intervals 8 Delta nu_2 - Delta nu_1. Nuclear effects for are not
important this difference and it is of use to study higher-order QED
corrections.Comment: 10 pages, presented at Hydrogen Atom II meeting (2000
Monoclonal Antibodies Opsonize <i>Burkholderia</i> spp. and Reduce Intracellular Actin Tail Formation in a Macrophage Infection Assay
Melioidosis is difficult to treat successfully due to the causal bacterium being resistant to many classes of antibiotics, therefore limiting available therapeutic options. New and improved therapies are urgently required to treat this disease.</jats:p
Effect of Periodontal Treatment on HbA1c among Patients with Prediabetes
Evidence is limited regarding whether periodontal treatment improves hemoglobin A1c (HbA1c) among people with prediabetes and periodontal disease, and it is unknown whether improvement of metabolic status persists >3 mo. In an exploratory post hoc analysis of the multicenter randomized controlled trial âAntibiotika und Parodontitisâ (Antibiotics and Periodontitis)âa prospective, stratified, double-blind studyâwe assessed whether nonsurgical periodontal treatment with or without an adjunctive systemic antibiotic treatment affects HbA1c and high-sensitivity C-reactive protein (hsCRP) levels among periodontitis patients with normal HbA1c (â€5.7%, n = 218), prediabetes (5.7% 1 mm in both groups. In the normal HbA1c group, HbA1c values remained unchanged at 5.0% (95% CI, 4.9% to 6.1%) during the observation period. Among periodontitis patients with prediabetes, HbA1c decreased from 5.9% (95% CI, 5.9% to 6.0%) to 5.4% (95% CI, 5.3% to 5.5%) at 15.5 mo and increased to 5.6% (95% CI, 5.4% to 5.7%) after 27.5 mo. At 27.5 mo, 46% of periodontitis patients with prediabetes had normal HbA1c levels, whereas 47.9% remained unchanged and 6.3% progressed to diabetes. Median hsCRP values were reduced in the normal HbA1c and prediabetes groups from 1.2 and 1.4 mg/L to 0.7 and 0.7 mg/L, respectively. Nonsurgical periodontal treatment may improve blood glucose values among periodontitis patients with prediabetes (ClinicalTrials.gov NCT00707369)
Clusters and networks as enablers of product and process innovation
One of the strategies adopted in the Philippines to facilitate a more consistent supply of good quality vegetables from smallholder farmers is the clustering approach, whereby a small group or cluster of smallholder farmers is organized to deliver a pre-determined amount of produce to a focal customer (CRS-Philippines, 2007). Developed from the CIAT Territorial Approach, the CRS Eight Step Clustering Approach for Agro-enterprise Development employs a participatory action learning process, where the cluster members proactively plan their production to meet the specifc quality and delivery requirements of their focal customer. The clustering approach is a strategy which allows smallholder farmers to access higher value chains. Evidence is provided to demonstrate how several of the clusters facilitated have utilised the skills and knowledge acquired in servicing their focal customer to develop new products for new markets, to adopt alternative low cost systems of production to reduce their reliance on external inputs, to reduce postharvest losses and product deterioration through improved packaging, to improve access to low cost community-based loans and to take advantage of local and national government grants that provide production inputs and support the development of community-based infrastructure projects
Manganese hyperaccumulation capacity of Ilex paraguariensis A. St. Hil. and occurrence of interveinal chlorosis induced by transient toxicity.
Manganese (Mn) toxicity is common in plants grown on very acid soils. However, some plants species that grow in this condition can take up high amounts of Mn and are referred to as hyperaccumulating species. In this study, we evaluated the capacity of Ilex paraguariensis to accumulate Mn and the effect of excessive concentrations on plant growth and nutrition. For this, a container experiment was conducted using soils from different parent materials (basalt and sandstone), with and without liming, and at six doses of applied Mn (0, 30, 90, 270, 540 and 1,080 mg kg 1). Clonal plants grown for 203 days were harvested to evaluate yield, and leaf tissue samples were evaluated for Mn and other elements. Without liming and with high Mn doses, leaf Mn concentrations reached 13,452 and 12,127 mg kg 1 in sandstone and basalt soils, respectively; concentrations in excess of 10,000 mg kg 1 are characteristic of hyperaccumulating plants. Liming reduced these values to 7203 and 8030 mg kg 1. More plant growth accompanied increased Mn leaf concentrations, with a growth reduction noted at the highest dose in unlimed soils. Elemental distribution showed Mn presence in the mesophyll, primarily in vascular bundles, without high Mn precipitates. Interveinal chlorosis of young leaves associated with high Mn concentration and lower Fe concentrations was observed, especially in sandstone soil without liming. However, the occurrence of this symptom was not associated with decreased plant growth
Precision Study of Positronium: Testing Bound State QED Theory
As an unstable light pure leptonic system, positronium is a very specific
probe atom to test bound state QED. In contrast to ordinary QED for free
leptons, the bound state QED theory is not so well understood and bound state
approaches deserve highly accurate tests. We present a brief overview of
precision studies of positronium paying special attention to uncertainties of
theory as well as comparison of theory and experiment. We also consider in
detail advantages and disadvantages of positronium tests compared to other QED
experiments.Comment: A talk presented at Workshop on Positronium Physics (ETH Zurich, May
30-31, 2003
Conceptual design of a nonscaling fixed field alternating gradient accelerator for protons and carbon ions for charged particle therapy
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articleâs title, journal citation, and DOI.The conceptual design for a nonscaling fixed field alternating gradient accelerator suitable for charged particle therapy (the use of protons and other light ions to treat some forms of cancer) is described.EPSR
Characterization of prion disease associated with a two-octapeptide repeat insertion
Genetic prion disease accounts for 10â15% of prion disease. While insertion of four or more octapeptide repeats are clearly pathogenic, smaller repeat insertions have an unclear pathogenicity. The goal of this case series was to provide an insight into the characteristics of the 2-octapeptide repeat genetic variant and to provide insight into the risk for CreutzfeldtâJakob disease in asymptomatic carriers. 2-octapeptide repeat insertion prion disease cases were collected from the National Prion Disease Pathology Surveillance Center (US), the National Prion Clinic (UK), and the National CreutzfeldtâJakob Disease Registry (Australia). Three largescale population genetic databases were queried for the 2-octapeptide repeat insertion allele. Eight cases of 2-octapeptide repeat insertion were identified. The cases were indistinguishable from the sporadic CreutzfeldtâJakob cases of the same molecular subtype. Western blot characterization of the prion protein in the absence of enzymatic digestion with proteinase K revealed that 2-octapeptide repeat insertion and sporadic CreutzfeldtâJakob disease have distinct prion protein profiles. Interrogation of large-scale population datasets suggested the variant is of very low penetrance. The 2-octapeptide repeat insertion is at most a low-risk genetic variant. Predictive genetic testing for asymptomatic blood relatives is not likely to be justified given the low risk
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