Epidemiological impact of waning immunization on a vaccinated population

This is an epidemiological SIRV model based study that is de- signed to analyze the impact of vaccination in containing infection spread, in a 4-tiered population compartment comprised of susceptible, infected, recov- ered and vaccinated agents. While many models assume a lifelong protection through vaccination, we focus on the impact of waning immunization due to conversion of vaccinated and recovered agents back to susceptible ones. Two asymptotic states exist, the \disease-free equilibrium" and the \endemic equi- librium" and we express the transitions between these states as function of the vaccination and conversion rates and using the basic reproduction number. We nd that the vaccination of newborns and adults have dierent consequences on controlling an epidemic. Also, a decaying disease protection within the re- covered sub-population is not sucient to trigger an epidemic on the linear level. We perform simulations for a parameter set modelling a disease with waning immunization like pertussis. For a diusively coupled population, a transition to the endemic state can proceed via the propagation of a traveling infection wave, described successfully within a Fisher-Kolmogorov framework

The effect of salt on the structure of individual fat globules and the microstructure of dry salted cheddar cheese

Salting is an essential step in the production of Cheddar and other cheese varieties and is a well-studied process but the effect of salt addition on the microstructure of the milk ingredients and resulting cheese is not well known. This study provides insights into how the primary components in milk and the cheese matrix respond to salting. High concentrations of salt (15\u201325% (w/w) NaCl) disrupted fat globules due to the increased osmotic pressure. This led to fat coalescence, resulting in large fat globules >10 \u3bcm in diameter, together with submicron sized fat globules ~ 120\u2013500 nm in diameter. Salt addition also prevented the visualization of the milk fat globule membrane when added at high concentrations (25% (w/w) NaCl) and induced asymmetry in liquid ordered domains at lower concentrations (10% (w/w) NaCl). The microstructure of the surface of the milled curd was compacted by salt, appearing coarse with 5% (w/w) NaCl or more hydrated with a denser protein structure with 2.5% (w/w) NaCl. After pressing, the curd junctions were fine and thin within the unsalted sample but coarse and thick where 5% (w/w) NaCl was added. Such coarse junctions appear to reduce binding between curd particles leading to a less cohesive cheese. Our results show that NaCl can significantly impact on the structure of fat and protein matrix of the curd surface if salt is not evenly distributed during dry salting. High concentrations of salt can also change the microstructure and texture of the cheese, resulting in a more heterogeneous product

The effects of sucrose, silver nitrate, plant growth regulators, and ammonium nitrate on microrhizome induction in perennially-cultivated ginger (Zingiber officinale Roscoe) from Hue, Vietnam

The number of research on ginger microrhizome production is low, despite awareness of the drawbacks to the traditional method of cultivation and the known health benefits associated with ginger essential oils. We examined the effects of several factors on microrhizome induction in order to create a production protocol for the cultivar found in Hue, Vietnam. To determine the optimal conditions for ginger microrhizome production, different concentrations of sucrose, plant growth regulators, ammonium nitrate, and silver nitrate were investigated. Microrhizome fresh weight and diameter were increased to the maximum values with application of BAP (6-benzyl amino purine), NAA (α- naphthaleneacetic acid), IBA (indole-3-butyric acid), and a low ammonium nitrate concentration, with 0.433 g at 9.03 mm, 0.437 g at 9.73 mm, 0.478 g at 10.80 mm, and 0.449 g at 9.53 mm, respectively. Additionally, we demonstrated that kinetin has an inhibitory effect on microrhizome growth. The biggest microrhizomes were grown on MS media containing the optimal concentrations for each factor – 80 g/L sucrose, 1.9 mg/L AgNO3, 550 mg/L ammonium nitrate, 4 mg/L BAP, 6 mg/L NAA, and 4 mg/L IB