Entanglement in nuclear quadrupole resonance

Entangled quantum states are an important element of quantum information techniques. We determine the requirements for states of quadrupolar nuclei with spins >1/2 to be entangled. It was shown that entanglement is achieved at low temperature by applying a magnetic field to a quadrupolar nuclei possess quadrupole moments, which interacts with the electricfield gradient produced by the charge distribution in their surroundings.Comment: 9 pages, 5 figure

Erosion characteristics and horizontal variability for small erosion depths in the Sacramento-San Joaquin River Delta, California, USA

Erodibility of cohesive sediment in the Sacramento-San Joaquin River Delta (Delta) was investigated with an erosion microcosm. Erosion depths in the Delta and in the microcosm were estimated to be about one floc diameter over a range of shear stresses and times comparable to half of a typical tidal cycle. Using the conventional assumption of horizontally homogeneous bed sediment, data from 27 of 34 microcosm experiments indicate that the erosion rate coefficient increased as eroded mass increased, contrary to theory. We believe that small erosion depths, erosion rate coefficient deviation from theory, and visual observation of horizontally varying biota and texture at the sediment surface indicate that erosion cannot solely be a function of depth but must also vary horizontally. We test this hypothesis by developing a simple numerical model that includes horizontal heterogeneity, use it to develop an artificial time series of suspended-sediment concentration (SSC) in an erosion microcosm, then analyze that time series assuming horizontal homogeneity. A shear vane was used to estimate that the horizontal standard deviation of critical shear stress was about 30% of the mean value at a site in the Delta. The numerical model of the erosion microcosm included a normal distribution of initial critical shear stress, a linear increase in critical shear stress with eroded mass, an exponential decrease of erosion rate coefficient with eroded mass, and a stepped increase in applied shear stress. The maximum SSC for each step increased gradually, thus confounding identification of a single well-defined critical shear stress as encountered with the empirical data. Analysis of the artificial SSC time series with the assumption of a homogeneous bed reproduced the original profile of critical shear stress, but the erosion rate coefficient increased with eroded mass, similar to the empirical data. Thus, the numerical experiment confirms the small-depth erosion hypothesis. A linear model of critical shear stress and eroded mass is proposed to simulate small-depth erosion, assuming that the applied and critical shear stresses quickly reach equilibrium

Measuring and modelling the response of Klebsiella pneumoniae KPC prey to Bdellovibrio bacteriovorus predation, in human serum and defined buffer

In worldwide conditions of increasingly antibiotic-resistant hospital infections, it is important to research alternative therapies. Bdellovibrio bacteriovorus bacteria naturally prey on Gram-negative pathogens, including antibiotic-resistant strains and so B. bacteriovorus have been proposed as "living antibiotics" to combat antimicrobially-resistant pathogens. Predator-prey interactions are complex and can be altered by environmental components. To be effective B. bacteriovorus predation needs to work in human body fluids such as serum where predation dynamics may differ to that studied in laboratory media. Here we combine mathematical modelling and lab experimentation to investigate the predation of an important carbapenem-resistant human pathogen, Klebsiella pneumoniae, by B. bacteriovorus in human serum versus buffer. We show experimentally that B. bacteriovorus is able to reduce prey numbers in each environment, on different timescales. Our mathematical model captures the underlying dynamics of the experimentation, including an initial predation-delay at the predator-prey-serum interface. Our research shows differences between predation in buffer and serum and highlights both the potential and limitations of B. bacteriovorus acting therapeutically against K. pneumoniae in serum, informing future research into the medicinal behaviours and dosing of this living antibacterial

Elucidation of the tumoritropic principle of hypericin

Hypericin is a potent agent in the photodynamic therapy of cancers. To better understand its tumoritropic behaviour, we evaluated the major determinants of the accumulation and dispersion of hypericin in subcutaneously growing mouse tumours. A rapid exponential decay in tumour accumulation of hypericin as a function of tumour weight was observed for each of the six tumour models investigated, and a similar relationship was found between tumour blood flow and tumour weight. Moreover, there was a close correlation between the higher hypericin uptake in RIF-1 tumours compared to R1 tumours and tumour vessel permeability. To define the role of lipoproteins in the transport of hypericin through the interstitial space, we performed a visual and quantitative analysis of the colocalisation of hypericin and DiOC18-labelled lipoproteins in microscopic fluorescent overlay images. A coupled dynamic behaviour was found early after injection (normalised fluorescence intensity differences were on the whole less than 10%), while a shifted pattern in localisation of hypericin and DiOC18 was seen after 24 h, suggesting that during its migration through the tumour mass, hypericin is released from the lipoprotein complex. In conclusion, we were able to show that the tumour accumulation of hypericin is critically determined by a combination of biological (blood flow, vessel permeability) and physicochemical elements (affinity for interstitial constituents)

Conditional Gene Expression in Mycobacterium abscessus

Mycobacterium abscessus is an emerging human pathogen responsible for lung infections, skin and soft-tissue infections and disseminated infections in immunocompromised patients. It may exist either as a smooth (S) or rough (R) morphotype, the latter being associated with increased pathogenicity in various models. Genetic tools for homologous recombination and conditional gene expression are desperately needed to allow the study of M. abscessus virulence. However, descriptions of knock-out (KO) mutants in M. abscessus are rare, with only one KO mutant from an S strain described so far. Moreover, of the three major tools developed for homologous recombination in mycobacteria, only the one based on expression of phage recombinases is working. Several conditional gene expression tools have recently been engineered for Mycobacterium tuberculosis and Mycobacterium smegmatis, but none have been tested yet in M. abscessus. Based on previous experience with genetic tools allowing homologous recombination and their failure in M. abscessus, we evaluated the potential interest of a conditional gene expression approach using a system derived from the two repressors system, TetR/PipOFF. After several steps necessary to adapt TetR/PipOFF for M. abscessus, we have shown the efficiency of this system for conditional expression of an essential mycobacterial gene, fadD32. Inhibition of fadD32 was demonstrated for both the S and R isotypes, with marginally better efficiency for the R isotype. Conditional gene expression using the dedicated TetR/PipOFF system vectors developed here is effective in S and R M. abscessus, and may constitute an interesting approach for future genetic studies in this pathogen

Taping patients with clinical signs of subacromial impingement syndrome: the design of a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Shoulder problems are a common complaint of the musculoskeletal system. Physical therapists treat these patients with different modalities such as exercise, massage, and shoulder taping. Although different techniques have been described, the effectiveness of taping has not yet been established. The aim of this study is to assess the effectiveness and cost-effectiveness of usual physical therapy care in combination with a particular tape technique for subacromial impingement syndrome of the shoulder compared to usual physical therapy care without this tape technique in a primary healthcare setting.</p> <p>Methods and design</p> <p>An economic evaluation alongside a randomized controlled trial will be conducted. A sample of 140 patients between 18 and 65 years of age with a diagnosis of subacromial impingement syndrome (SAIS) as assessed by physical therapists will be recruited. Eligible patients will be randomized to either the intervention group (usual care in combination with the particular tape technique) or the control group (usual care without this tape technique). In both groups, usual care will consist of individualized physical therapy care. The primary outcomes will be shoulder-specific function (the Simple Shoulder Test) and pain severity (11-point numerical rating scale). The economic evaluation will be performed using a societal perspective. All relevant costs will be registered using cost diaries. Utilities (Quality Adjusted Life Years) will be measured using the EuroQol. The data will be collected at baseline, and 4, 12, and 26 weeks follow-up.</p> <p>Discussion</p> <p>This pragmatic study will provide information about the effectiveness and cost-effectiveness of taping in patients presenting with clinical signs of SAIS.</p> <p>Trial registration</p> <p>Trial registration number: <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2575">NTR2575</a></p

Slab melting as a barrier to deep carbon subduction

Interactions between crustal and mantle reservoirs dominate the surface inventory of volatile elements over geological time, moderating atmospheric composition and maintaining a lifesupporting planet1. While volcanoes expel volatile components into surface reservoirs, subduction of oceanic crust is responsible for replenishment of mantle reservoirs2,3. Many natural, ‘superdeep’ diamonds originating in the deep upper mantle and transition zone host mineral inclusions, indicating an affinity to subducted oceanic crust4–7. Here we show that the majority of slab geotherms will intersect a deep depression along the melting curve of carbonated oceanic crust at depths of approximately 300 to 700 kilometres, creating a barrier to direct carbonate recycling into the deep mantle. Low-degree partial melts are alkaline carbonatites that are highly reactive with reduced ambient mantle, producing diamond. Many inclusions in superdeep diamonds are best explained by carbonate melt–peridotite reaction. A deep carbon barrier may dominate the recycling of carbon in the mantle and contribute to chemical and isotopic heterogeneity of the mantle reservoir

Non-monotonic changes in clonogenic cell survival induced by disulphonated aluminum phthalocyanine photodynamic treatment in a human glioma cell line

<p>Abstract</p> <p>Background</p> <p>Photodynamic therapy (PDT) involves excitation of sensitizer molecules by visible light in the presence of molecular oxygen, thereby generating reactive oxygen species (ROS) through electron/energy transfer processes. The ROS, thus produced can cause damage to both the structure and the function of the cellular constituents resulting in cell death. Our preliminary investigations of dose-response relationships in a human glioma cell line (BMG-1) showed that disulphonated aluminum phthalocyanine (AlPcS₂) photodynamically induced loss of cell survival in a concentration dependent manner up to 1 μM, further increases in AlPcS₂concentration (>1 μM) were, however, observed to decrease the photodynamic toxicity. Considering the fact that for most photosensitizers only monotonic dose-response (survival) relationships have been reported, this result was unexpected. The present studies were, therefore, undertaken to further investigate the concentration dependent photodynamic effects of AlPcS₂.</p> <p>Methods</p> <p>Concentration-dependent cellular uptake, sub-cellular localization, proliferation and photodynamic effects of AlPcS₂were investigated in BMG-1 cells by absorbance and fluorescence measurements, image analysis, cell counting and colony forming assays, flow cytometry and micronuclei formation respectively.</p> <p>Results</p> <p>The cellular uptake as a function of extra-cellular AlPcS₂concentrations was observed to be biphasic. AlPcS₂was distributed throughout the cytoplasm with intense fluorescence in the perinuclear regions at a concentration of 1 μM, while a weak diffuse fluorescence was observed at higher concentrations. A concentration-dependent decrease in cell proliferation with accumulation of cells in G₂+M phase was observed after PDT. The response of clonogenic survival after AlPcS₂-PDT was non-monotonic with respect to AlPcS₂concentration.</p> <p>Conclusions</p> <p>Based on the results we conclude that concentration-dependent changes in physico-chemical properties of sensitizer such as aggregation may influence intracellular transport and localization of photosensitizer. Consequent modifications in the photodynamic induction of lesions and their repair leading to different modes of cell death may contribute to the observed non-linear effects.</p