1,176 research outputs found

    Association between self-reported general and mental health and adverse outcomes: a retrospective cohort study of 19 625 Scottish adults

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    <b>Objective</b><p></p> Self-reported general health and mental health are independent predictors of all-cause mortality. This study examines whether they are also independent predictors of incident cancer, coronary heart disease and psychiatric hospitalisation. <b>Methods</b><p></p> We conducted a retrospective, population cohort study by linking the 19 625 Scottish adults who participated in the Scottish Health Surveys 1995–2003, to hospital admissions, cancer registration and death certificate records. We conducted Cox proportional hazard models adjusting for potential confounders including age, sex, socioeconomic status, alcohol, smoking status, body mass index, hypertension and diabetes. <b>Results</b><p></p> Poor general health was reported by 1215 (6.2%) participants and was associated with cancer registrations (adjusted Hazard Ratio [HR] 1.30, 95% CI 1.10, 1.55), coronary heart disease events (adjusted HR 2.30, 95% CI 1.86, 2.84) and psychiatric hospitalisations (adjusted HR 2.42, 95% CI 1.65, 3.56). There was evidence of dose relationships and the associations remained significant after adjustment for mental health. 3172 (16%) participants had poor mental health (GHQ ≥4). After adjustment for general health, the associations between poor mental health and coronary heart disease events (adjusted HR 1.36, 95% CI 1.13, 1.63) and all-cause death (adjusted HR 1.38, 95% CI 1.23, 1.55) became non-significant, but mental health remained associated with psychiatric hospitalisations (fully adjusted HR 2.02, 95% CI 1.48, 2.75). <b>Conclusion</b><p></p> Self-reported general health is a significant predictor of a range of clinical outcomes independent of mental health. The association between mental health and non-psychiatric outcomes is mediated by general health but it is an independent predictor of psychiatric outcome. Individuals with poor general health or mental health warrant close attention

    The Synthesis and Characterization of New, Robust Titanium (IV) Scorpionate Complexes

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    Titanium complexes possessing sterically encumbered ligands have allowed for the preparation of reactive moieties (imido, alkylidene and alkylidyne species) relevant to reactions such as olefin polymerization and alkyne hydroamination. For this reason, we have targeted robust scorpionate ancillary ligands to support reactive titanium centers. Thus, a series of titanium complexes were synthesized using an achiral oxazoline-based scorpionate ligand, tris(4,4-dimethyl-2-oxazolinyl)phenyl borate [To^M^]^-^ as well as the related chiral ligand, tris(4-isopropyl-2-oxazolinyl)phenyl borate [To^P^]^-^. The complex [Ti(κ^3^- To^M^)Cl~3~] was prepared in moderate yield (43%) by the rapid (<1 min at room temperature) reaction of Li[To^M^] and TiCl~4~ in methylene chloride; this new compound was characterized by ^1^H NMR spectroscopy as the expected C~3v~-symmetric species. One route to Ti (IV) alkyls involves salt metathesis; accordingly, syntheses of [To^M^]Ti alkyl complexes by interaction of [Ti(κ^3^-To^M^)Cl~3~] and one or three equivalents of alkylating agents, such as benzyl potassium (KCH~2~C~6~H~5~), trimethylsilylmethyl
lithium (LiCH~2~Si(CH~3~) ~3~), or neopentyl lithium (LiCH~2~C(CH~3~)~3~) are currently under investigation. The complexes [Ti(=NBut) (κ~3~-To^M^)(Cl)(Bu^t^py)] (Bu^t^py=4 tert-butylpyridine) and [Ti(=NBu^t^) (κ~3~-To^P^)(Cl)(Bu^t^py)] were synthesized by reaction of the known Ti imido [Ti(=NBu^t^)(Cl)~2~(Bu^t^py)~2~] with Li[To^M^] or Li[To^P^], respectively, by stirring overnight in methylene chloride at ambient temperature. The complexes were identified using ^1^H NMR spectroscopy, ^1^H-^13^C HMQC and ^1^H-^15^N HMBC correlation experiments

    Stress development, relaxation, and memory in colloidal dispersions: Transient nonlinear microrheology

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    The motion of a single Brownian particle in a complex fluid can reveal material behavior both at and away from equilibrium. In active microrheology, a probe particle is driven by an external force through a complex medium and its motion studied in order to infer properties of the embedding material. Most work in microrheology has focused on steady behavior and established the relationship between the motion of the probe, the microstructure, and the effective microviscosity of the medium. Transient behavior in the near-equilibrium, linear-response regime has also been studied via its connection to low-amplitude oscillatory probe forcing and the complex modulus; at very weak forcing, the microstructural response that drives viscosity is indistinguishable from equilibrium fluctuations. But important information about the basic physical aspects of structural development and relaxation in a medium is captured by startup and cessation of the imposed deformation in the nonlinear regime, where the structure is driven far from equilibrium. Here, we study theoretically and by dynamic simulation the transient behavior of a colloidal dispersion undergoing nonlinear microrheological forcing. The strength with which the probe is forced, Fext, compared to thermal forces, kT/b, governs the dynamics and defines a Péclet number, Pe = F^ext/(kT/b), where kT is the thermal energy and b is the colloidal bath particle size. For large Pe, a boundary layer (in which unsteady advection balances diffusion) forms at particle contact on the time scale of the flow, a/U, where a is the probe size and U its speed, whereas the wake forms over O(Pe) diffusive time steps. Similarly, relaxation following cessation occurs over several time scales corresponding to distinct physical processes. For very short times, the time scale for relaxation is set by a boundary layer of thickness δ ∼ (a+b)/Pe, and so τ ∼ δ^2/D_r, where Dr is the relative diffusivity between the probe of size a and a bath particle. Nearly all stress relaxation occurs during this time. At longer times, the Brownian diffusion of the bath particles acts to close the wake on a time scale set by how long it takes a bath particle to diffuse laterally across it, τ ∼ (a+b)^2/D_r. Although the majority of the microstructural relaxation occurs during this wake-healing process, it does so with little change in the stress. Also during relaxation, the probe travels backward in the suspension; this recovered strain is proportional to the free energy stored in the compressed particle configuration, an indicator that the stress is proportional to the free energy density stored entropically in the microstructure. Theoretical results are compared with Brownian dynamics simulation where it is found that the dilute theory captures the correct behavior even for concentrated suspensions. Two modes of forcing are studied: Constant force and constant velocity. Results are compared to analogous macrorheology results for suspensions undergoing simple shear flow

    Single-particle motion in colloids: force-induced diffusion

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    We study the fluctuating motion of a Brownian-sized probe particle as it is dragged by a constant external force through a colloidal dispersion. In this nonlinear-microrheology problem, collisions between the probe and the background bath particles, in addition to thermal fluctuations of the solvent, drive a long-time diffusive spread of the probe's trajectory. The influence of the former is determined by the spatial configuration of the bath particles and the force with which the probe perturbs it. With no external forcing the probe and bath particles form an equilibrium microstructure that fluctuates thermally with the solvent. Probe motion through the dispersion distorts the microstructure; the character of this deformation, and hence its influence on the probe's motion, depends on the strength with which the probe is forced, F^(ext), compared to thermal forces, kT/b, defining a Péclet number, Pe = F^(ext)/(kT/b), where kT is the thermal energy and b the bath particle size. It is shown that the long-time mean-square fluctuational motion of the probe is diffusive and the effective diffusivity of the forced probe is determined for the full range of Péclet number. At small Pe Brownian motion dominates and the diffusive behaviour of the probe characteristic of passive microrheology is recovered, but with an incremental flow-induced ‘microdiffusivity’ that scales as D^(micro) ~ D_aPe^2φ_b, where φ_b is the volume fraction of bath particles and D_a is the self-diffusivity of an isolated probe. At the other extreme of high Péclet number the fluctuational motion is still diffusive, and the diffusivity becomes primarily force induced, scaling as (F^(ext)/η)φ_b, where η is the viscosity of the solvent. The force-induced microdiffusivity is anisotropic, with diffusion longitudinal to the direction of forcing larger in both limits compared to transverse diffusion, but more strongly so in the high-Pe limit. The diffusivity is computed for all Pe for a probe of size a in a bath of colloidal particles, all of size b, for arbitrary size ratio a/b, neglecting hydrodynamic interactions. The results are compared with the force-induced diffusion measured by Brownian dynamics simulation. The theory is also compared to the analogous shear-induced diffusion of macrorheology, as well as to experimental results for macroscopic falling-ball rheometry. The results of this analysis may also be applied to the diffusive motion of self-propelled particles

    Investigations of different strategies for high frequency regeneration of Dendrobium malones ‘Victory’

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    Regeneration of orchid, Dendrobium malones “Victory”, has been established by direct differentiation and through callus formation. With direct thin leaf section differentiation method, the number of protocorm like bodies (PLBs) formed from Thin Section (TS) explants obtainedfrom a single leaf was 10 times more than that from a single whole leaf, in a short time period. This therefore suggested that the proliferation potential is distributed all along the seedling leaves and morphogenically competent cells were not limited in the basal ends or the tips of the leaves in TS of orchid leaf cultures. Full MS media supplemented with auxins/cytokinins either in single orin combination along with peptone, yeast extract, casein hydrolysate (each at 100 mg/l), banana powder (40 g/l), 15% coconut water and 2% sucrose have shown excellent results for high frequency regeneration in orchid cultures. In many higher plants, regenerating leaves responded by developing proliferative loci in some “Predetermined Regenerative” cells in the dermal layers by tissue culture methods

    Improving The Students' Speaking Accuracy Through “Lse 9.0 Software Version”

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    The objective of the research was to find out the improvement students' speaking accuracy through Learn to Speak English 9.0 Software Version at SMK Negeri 1 Pattallassang Gowa. This research used classroom action research that consists two cycles. The research object was the first year electric students' of SMK Negeri 1 Pattallassang Gowa academic year 2011/2012. The object of this research consisted of 32 students. The researcher obtained the data by using the speaking test in the diagnostic test, the cycle I and Cycle II. The results of the student's speaking test in cycle I and cycle II had significantly different scores. There was a better improvement of gains by students at the end of action cycle II. The research findings indicated that use of Learn to Speak English 9.0 Software as teaching media could improve the students' speaking accuracy after evaluation in cycles I and II, the means scores in diagnostic test is 5.21 and then it became 5.95 in the cycle I and 7.10 in the cycle II. It can be stated that the students' speaking accuracy at the first year electric students' of SMK Negeri 1 Pattallassang Gowa was in poor level after the test in the diagnostic test with mean score 5.21 had improved to fairly good level after the test in the cycle II with mean score 7.10

    Modeling hydrodynamic self-propulsion with Stokesian Dynamics. Or teaching Stokesian Dynamics to swim

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    We develop a general framework for modeling the hydrodynamic self-propulsion (i.e., swimming) of bodies (e.g., microorganisms) at low Reynolds number via Stokesian Dynamics simulations. The swimming body is composed of many spherical particles constrained to form an assembly that deforms via relative motion of its constituent particles. The resistance tensor describing the hydrodynamic interactions among the individual particles maps directly onto that for the assembly. Specifying a particular swimming gait and imposing the condition that the swimming body is force- and torque-free determine the propulsive speed. The body’s translational and rotational velocities computed via this methodology are identical in form to that from the classical theory for the swimming of arbitrary bodies at low Reynolds number. We illustrate the generality of the method through simulations of a wide array of swimming bodies: pushers and pullers, spinners, the Taylor=Purcell swimming toroid, Taylor’s helical swimmer, Purcell’s three-link swimmer, and an amoeba-like body undergoing large-scale deformation. An open source code is a part of the supplementary material and can be used to simulate the swimming of a body with arbitrary geometry and swimming gait

    Contracting of primary health care services in Pakistan: is up-scaling a pragmatic thinking

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    Quite often, public health care systems in developing countries are struggling because of incompetence and a lack of provider responsiveness to the needs of consumers. On the contrary, the private sector dominates the system of health provision. In recent years, contracting has been experimented as an approach to ensure delivery of comprehensive public health services in an efficient, effective, superior and fair manner and has generally thrived well. The state\u27s healthcare system in Pakistan has suffered a lot, owing to structural fragmentation, resource scarcity, inefficiency and lack of functional specificity, gender insensitivity and inaccessibility. However, partnering with the private sector has shown some exceptional accomplishments. Though challenging but structural reforms, involving private health sector have become indispensable. The overall experience shows that up-scaling of such initiatives in the country would require lot of cautions to be taken by the government

    Gas permeation through a polymer network

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    We study the diffusion of gas molecules through a two-dimensional network of polymers with the help of Monte Carlo simulations. The polymers are modeled as non-interacting random walks on the bonds of a two-dimensional square lattice, while the gas particles occupy the lattice cells. When a particle attempts to jump to a nearest-neighbor empty cell, it has to overcome an energy barrier which is determined by the number of polymer segments on the bond separating the two cells. We investigate the gas current JJ as a function of the mean segment density ρ\rho, the polymer length \ell and the probability qmq^{m} for hopping across mm segments. Whereas JJ decreases monotonically with ρ\rho for fixed \ell, its behavior for fixed ρ\rho and increasing \ell depends strongly on qq. For small, non-zero qq, JJ appears to increase slowly with \ell. In contrast, for q=0q=0, it is dominated by the underlying percolation problem and can be non-monotonic. We provide heuristic arguments to put these interesting phenomena into context.Comment: Dedicated to Lothar Schaefer on the occasion of his 60th birthday. 11 pages, 3 figure

    Fluctuations and correlations in an individual-based model of biological coevolution

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    We extend our study of a simple model of biological coevolution to its statistical properties. Staring with a complete description in terms of a master equation, we provide its relation to the deterministic evolution equations used in previous investigations. The stationary states of the mutationless model are generally well approximated by Gaussian distributions, so that the fluctuations and correlations of the populations can be computed analytically. Several specific cases are studied by Monte Carlo simulations, and there is excellent agreement between the data and the theoretical predictions.Comment: 25 pages, 2 figure
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