Preparation and characterization of antibacterial cobalt-exchanged natural zeolite/poly(vinyl alcohol) hydrogels

In the present study, potential application of the local clinoptilolite-rich natural zeolite in formulation of antibacterial hydrogels was investigated. The zeolite powder exchanged with cobalt(II) ions was used in preparation of the zeolite/poly(vinyl alcohol) hydrogel films in different amounts. The films were physically crosslinked by the freezing-thawing method and characterized for their crystallinity, surface and cross sectional morphology, chemical composition, thermal behaviour, mechanical properties, swelling and dissolution behaviours, and antibacterial activities against a Gram-negative bacteria. The films with 0.48 wt% and higher cobalt-exchanged zeolite contents showed antibacterial activity. Addition of the zeolite powder in the formulations did not cause significant changes in the other properties of the films.Turkish Republic Prime Ministry State Planning Organization (DPT-2006 K120690

Percentage of lethality across the three mammal species during plague challenge experiments.

<p>Percentage of lethality across the three mammal species during plague challenge experiments.</p

Comparison of the number of animals trapped in central areas in 1991 and 1995, and in both the central and peripheral areas from 1997 to 2014 in Mahajanga.

<p>Comparison of the number of animals trapped in central areas in 1991 and 1995, and in both the central and peripheral areas from 1997 to 2014 in Mahajanga.</p

Minimum spanning tree of 4,098 SNPs for 19 <i>Y</i>. <i>pestis</i> isolates from Mahajanga.

<p>The origins of the strains are distinguished by colors. Strain name is mentioned close to the circle. Numbers on the branch reflect the number of SNPs between two circles.</p

Chronogram of plague epidemics and animal trappings in Mahajanga: C: Number of human confirmed cases; P: Number of presumptive cases; S: Number of human suspected cases.

<p>Sm: no. of <i>S</i>. <i>murinus</i> trapped (% of total captures). Arrows red: human epidemic, green: rodent capture.</p

Effects of variation in disease parameters on the period (left column) and amplitude (right column) of the multiyear cycles predicted by model (1), for fixed values of β (labelled on plot) and different rodent population parameters ()

Parameter values are: (a, b) Kielder forest field voles; (c, d) Manor Wood bank voles; (e, f) French common voles; (g, h) northern Fennoscandian field voles. Results for all values of β, for all rodent population parameters, are given in . In the colour bar ‘n.d.’ denotes simulations in which the disease prevalence decays to zero during the course of the simulation. In these cases the susceptible population density exhibits regular annual cycles. Similarly, ‘n.c.’ denotes simulations in which disease remains endemic in the population and all four population components exhibit regular annual cycles. The dominant period of the multiyear dynamics was measured by spectral analysis (using fast Fourier transform) of 256 years of equilibrium population data, measured annually (see for a review). The amplitude was the difference between the maximum and the minimum total population density in this data set. For brevity we do not distinguish between regularly repeated multiyear cycles and irregular (pseudo-periodic) multiyear cycles.<p><b>Copyright information:</b></p><p>Taken from "Disease effects on reproduction can cause population cycles in seasonal environments"</p><p></p><p>The Journal of Animal Ecology 2008;77(2):378-389.</p><p>Published online Jan 2008</p><p>PMCID:PMC2408661.</p><p>© 2007 The Authors. Journal compilation © 2007 British Ecological Society</p

(a) Date in the year at which the infection threshold () is first exceeded, as a function of 1/τ

Parameter values are as in . Dotted lines denote 1/τ values used for the examples in . The critical τ at which the multiyear cycles occur (τ) is at 1/τ = 27 days in this example. (b) τ as a function of the length of the reproductive season, . Regular annual cycles occur in the regions denoted ‘NO M.Y. CYCLES’. Other parameter values and initial conditions are as in . We wrote a numerical code to run the model simulations for the full range of with these parameter values, and calculate τ to three decimal places when it could be found (dots), or give details of the predicted dynamics when τ could not be found.<p><b>Copyright information:</b></p><p>Taken from "Disease effects on reproduction can cause population cycles in seasonal environments"</p><p></p><p>The Journal of Animal Ecology 2008;77(2):378-389.</p><p>Published online Jan 2008</p><p>PMCID:PMC2408661.</p><p>© 2007 The Authors. Journal compilation © 2007 British Ecological Society</p

Epidemiological characteristics of the 19 strains of <i>Y</i>. <i>pestis</i> used for SNP typing.

<p>Epidemiological characteristics of the 19 strains of <i>Y</i>. <i>pestis</i> used for SNP typing.</p

(a) Correlation between ‘effective start date’ of the reproductive season, as defined in the main text, and the population density at varying times in the past

The dashed lines denote the correlation coefficient at which the probability of no significant relationship is = 0.05. (c) The same analysis as in (a), but correlating seroprevalence at the start of the reproductive season with past population densities; (b, d) ‘effective season start date’ and seroprevalence plotted against past population density for the corresponding highest significant positive correlation in (a) and (c), respectively. Zero on the vertical axis in (b) corresponds to no effective delay in the onset of the reproductive season. Parameter values are the same as for .<p><b>Copyright information:</b></p><p>Taken from "Disease effects on reproduction can cause population cycles in seasonal environments"</p><p></p><p>The Journal of Animal Ecology 2008;77(2):378-389.</p><p>Published online Jan 2008</p><p>PMCID:PMC2408661.</p><p>© 2007 The Authors. Journal compilation © 2007 British Ecological Society</p

Plague incidence anomalies data.

<p>(A) Monthly human plague incidence anomalies from 1960 to 2008 for Madagascar. (B) Associated continuous wavelet power spectrum. The dark contours denote power significance at the 95% level. (C) Global wavelet spectrum. A Gaussian filter has been applied before calculating the continuous wavelet power spectrum and the global spectrum.</p