Role of surface films in the germination of rust uredospores

1970 ◽  
Vol 48 (3) ◽  
pp. 499-511 ◽  
Author(s):  
William Woodbury ◽  
Mark A. Stahmann
Keyword(s):  
Surface Area ◽  
Water Surface ◽  
Surface Film ◽  
Storage Conditions ◽  
Surface Films ◽  
Film Material ◽  
Humid Atmosphere ◽  
Infection Structures ◽  
Film Area

An association of rust uredospores with materials which form films on water surfaces was demonstrated. One milligram of spores of Puccinia graminis tritici and 3.5 mg of Uromyces phaseoli spores released about 100 cm2 of film within 1 min of coming into contact with a large water surface. Oxidative reactions within these films, which were accelerated by light, formed products which inhibited spore germination. When spores were germinated on a large volume of water, germination varied with the surface area, which indicated that inhibitor was formed and retained at the water surface.Hydration of spores resulted in an increased germination, a decreased film area and a delay or prevention of film reactions. Storage of spores at lower humidities resulted in decreased germination, decreased film area, and film reactions which began as soon as the spores came into contact with the water surface. These results suggest that the effects of light and of storage conditions on germination may be mediated by surface film materials.The amount of surface film material released by wheat and bean rust spores may be correlated with the wetability of the host cuticle and also with the ability of rusts to differentiate infection structures in vitro on artificial membranes. On plastics which supported the formation of infection structures, spores acquired spherical infection droplets when exposed to a humid atmosphere. The surface area of these droplets was correlated with the area of surface film. It is suggested that surface film material may interact with the appropriate host cuticle to determine the size and configuration of infection droplets. This would provide a water surface of defined area upon which film reactions occur resulting in a sequence of products which control germination, directed growth of the germ tube and differentiation of infection structures.

Confinement And Control Of Oil Pollution On Water With Monomolecular Surface Films

1969 ◽  
Vol 1969 (1) ◽  
pp. 257-261 ◽  
Author(s):  
William D. Garrett
Keyword(s):  
Water Surface ◽  
Oil Pollution ◽  
Surface Film ◽  
Thick Layer ◽  
Surface Films ◽  
Film Material ◽  
Chemical Character ◽  
Favorable Conditions ◽  
And Control ◽  
Reduced Surface

Abstract Under favorable conditions monomolecular surface films can be used to guide, confine and condense petroleum spills on water. Composed of water-insoluable, non-toxic organic material, these films spread rapidly and spontaneously into a one-molecule-thick layer. Consequently, small quantities of piston-film material will clear thin oil layers from large areas of a water surface. The effects of wind, the chemical character of the pollution and its thickness upon the usefulness of the piston film will be discussed. In addition to clearing water surfaces of oil, one of the most useful applications may be the ability of the surface film to confine and condense a small oil spill into layers as thick as one centimeter. Since the petroleum is thickened and compressed into a much reduced surface area, the efficiency of oil retrieval techniques would be enhanced.

scholarly journals Snowpack-stored atmospheric surface-active contaminants traced with snowmelt water surface film rheology

2020 ◽  
Author(s):  
Stanisław J. Pogorzelski ◽  
Paweł Rochowski ◽  
Maciej Grzegorczyk ◽  
Katarzyna Boniewicz-Szmyt
Keyword(s):  
Surface Pressure ◽  
Water Surface ◽  
Temporal Evolution ◽  
Surface Film ◽  
Virial Equation ◽  
Rheological Parameters ◽  
Film Material ◽  
Structure Characteristics ◽  
Film Forming ◽  
Surface Active

Abstract The aim of the study was to quantify the adsorptive and thermo-elastic properties of snowmelt water surface films and their spatial-temporal evolution with snowpack structure characteristics and the entrapped surface-active organic composition. Surface pressure–area (π-A)T isotherms, surface pressure-temperature (π-T)A isochors, and stress–relaxation (π-t) measurements were performed using a Langmuir trough system on snowmelt water samples collected in a large-scale field studies performed at several industrialized and rural Tricity (Gdansk, Poland) areas at various environmental conditions and subsequent stages of the snowpack melting progress. Since the snow-melted water composition and concentrations of surface active organic matter fractions therein are largely undetermined, the force-area isotherm scaling formalisms (2D virial equation and 2D film scaling theory of polymeric films) were adapted to the complex mixture of surfactants. The surface film parameters and their spatial and temporal evolution turned out to be unequivocally related to principal signatures of the film-forming materials: surfactant concentrations (π, Alim), surface activity (Eisoth, |E|), film material solubility (R), surface material miscibility and 2D architecture complexity (y, βs), molecular thermal mobility (πk), and a timescale of the relaxation processes within the film (τi, |E|). Moreover, the parameters appeared to be correlated with snowpack structure characteristics (snow density ρ, specific snow area SSA, snow cover thickness), sample age time, and anthropogenic atmospheric contamination pressure source locations. In particular, Eisoth was found to be related to ρ and SSA, while R correlated with the solubility of film-forming organics which turned out to be long-chain fatty acids; similarly, spatial profiles of Eisoth revealed the peak values next to the areas being under a severe anthropogenic air pollution pressure. Snowmelt water films stand for a structurally heterogeneous (y > 10) interfacial system where several transition processes of differentiated time-scales (relaxation times from 7 to 63 s) took place leading to the apparent surface viscoelasticity. To sum up, the established surface rheological parameters could serve as novel indicators, based solely on physical attributes, allowing to follow the snowpack evolution, and its melting polymorphism in order to test or improve the existing snow-entrapped organics release models based on chemical analyses. The cross-correlation functional dependences of practical value remain to be established on the larger data set.

Formation of Dynamic Duolayer Systems at the Air/Water Interface by using Non-ionic Hydrophilic Polymers

2013 ◽  
Vol 66 (7) ◽  
pp. 807 ◽  
Author(s):  
Emma L. Prime ◽  
Diana N.H. Tran ◽  
Andy H.M Leung ◽  
Devi Sunartio ◽  
Greg G. Qiao ◽  
...  
Keyword(s):  
Water Surface ◽  
Surface Film ◽  
Lower Surface ◽  
Water Soluble ◽  
Vinyl Pyrrolidone ◽  
Surface Films ◽  
Brewster Angle Microscopy ◽  
Water Soluble Polymer ◽  
Spreading Pressure ◽  
Poly Vinyl Pyrrolidone

The inclusion of a water-soluble polymer, poly(vinyl pyrrolidone) (PVP), into a surface active film composition before application to the water surface leads to the formation of a dynamic duolayer; a novel surface film system. This duolayer shows improved surface viscosity over the monolayer compound alone, while the addition of polymer maintains other film properties such as evaporation control and equilibrium spreading pressure. Brewster Angle Microscopy shows that the duolayer film undergoes a different formation mechanism upon film compression, and the resultant surface pressure/area isotherm is different at lower surface pressures indicating the PVP is present on the water surface at these pressures and squeezed out to the water subphase at higher pressures. The addition of water-soluble polymers to form a dynamic duolayer provides a unique way to produce defect-free and tightly packed films while polymer is associated with the film. This finding provides new knowledge for the design of surface films with improved properties with potential applications in many areas.

A Descriptive in vitro Electron Microscopic Study of Acidic Fluoride-Treated Enamel: Potential Anti-Erosion Effects

2015 ◽  
Vol 49 (6) ◽  
pp. 618-625 ◽  
Author(s):  
Carl Hjortsjö ◽  
Alix Young ◽  
Andreas Kiesow ◽  
Andreas Cismak ◽  
Lutz Berthold ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Surface Film ◽  
Ion Beam ◽  
Dental Enamel ◽  
Surface Films ◽  
Electron Microscopic ◽  
Human Teeth ◽  
Cross Sectional

This study aimed to investigate the surface zones of acidic fluoride-treated enamel. Human teeth were each divided into three or four enamel specimens that were treated for 10 min with solutions of 0.2 and 0.4% HF (pH 3.09 and 2.94), 1.74% SnF2 (pH 2.9), 0.68% TiF4 (pH 1.6) and 0.84% NaF (pH 4.5). Untreated specimens functioned as negative controls. The microstructure and elemental composition of the surface zones were studied by scanning electron microscopy/energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and nanospot-EDX following cross-sectional preparation using focused ion beam technology. TEM/EDX analyses of NaF-treated specimens showed a 500-nm-thick closed surface film containing 20-40 at% (atomic percent) F. HF-treated specimens had a distinct surface film 200-600 nm thick (dense, not globular) containing 45-47 at% F. TiF4-treated specimens had a surface film of 200-300 nm in thickness containing 8-11 at% Ti but no detectable fluoride. SnF2-treated specimens had a modified surface enamel layer varying in thickness from 200 to 800 nm with an inhomogeneous distribution of Sn. Local spots were detected with as high as 8 at% Sn (30 wt%, weight percent). The results suggest that the reaction mechanisms of SnF2 and TiF4 solutions with dental enamel differ from those occurring after enamel exposure to acidulated NaF and HF solutions. While the HF and NaF treatments resulted in the formation of CaF2-like material as shown by EDX, no significant surface fluoridation was found for SnF2 and TiF4 solutions within the TEM/EDX detection limits. These results suggest that the erosion-protective mechanisms of these latter compounds probably relate more to the formation of hardly soluble and acid-resistant reaction surface films and less to surface fluoride incorporation.

Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion

1973 ◽  
Vol 31 ◽  
pp. 46-47
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Stress Corrosion ◽  
Zirconium Dioxide ◽  
Surface Film ◽  
Surface Films ◽  
Continuous Layer ◽  
Transmission Electron ◽  
Product Film

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.

scholarly journals Simple Equations Pertaining to the Particle Number and Surface Area of Metallic, Polymeric, Lipidic and Vesicular Nanocarriers

2021 ◽  
Vol 89 (2) ◽  
pp. 15
Author(s):  
M. R. Mozafari ◽  
E. Mazaheri ◽  
K. Dormiani
Keyword(s):  
Drug Delivery ◽  
Surface Area ◽  
Particle Number ◽  
Analytical Techniques ◽  
Metallic Particles ◽  
Nutraceutical Compounds ◽  
Mathematical Formulas ◽  
Simple Equations

Introduction: Bioactive encapsulation and drug delivery systems have already found their way to the market as efficient therapeutics to combat infections, viral diseases and different types of cancer. The fields of food fortification, nutraceutical supplementation and cosmeceuticals have also been getting the benefit of encapsulation technologies. Aim: Successful formulation of such therapeutic and nutraceutical compounds requires thorough analysis and assessment of certain characteristics including particle number and surface area without the need to employ sophisticated analytical techniques. Solution: Here we present simple mathematical formulas and equations used in the research and development of drug delivery and controlled release systems employed for bioactive encapsulation and targeting the sites of infection and cancer in vitro and in vivo. Systems covered in this entry include lipidic vesicles, polymeric capsules, metallic particles as well as surfactant- and tocopherol-based micro- and nanocarriers.

scholarly journals Newly Emerging Airborne Pollutants: Current Knowledge of Health Impact of Micro and Nanoplastics

2021 ◽  
Vol 18 (6) ◽  
pp. 2997
Author(s):  
Alessio Facciolà ◽  
Giuseppa Visalli ◽  
Marianna Pruiti Ciarello ◽  
Angela Di Pietro
Keyword(s):  
Surface Area ◽  
Current Knowledge ◽  
Oxidative Degradation ◽  
Health Impact ◽  
Outdoor Exposure ◽  
Environmental Matrices ◽  
Potential Health ◽  
Bodily Fluids

Plastics are ubiquitous persistent pollutants, forming the most representative material of the Anthropocene. In the environment, they undergo wear and tear (i.e., mechanical fragmentation, and slow photo and thermo-oxidative degradation) forming secondary microplastics (MPs). Further fragmentation of primary and secondary MPs results in nanoplastics (NPs). To assess potential health damage due to human exposure to airborne MPs and NPs, we summarize the evidence collected to date that, however, has almost completely focused on monitoring and the effects of airborne MPs. Only in vivo and in vitro studies have assessed the toxicity of NPs, and a standardized method for their analysis in environmental matrices is still missing. The main sources of indoor and outdoor exposure to these pollutants include synthetic textile fibers, rubber tires, upholstery and household furniture, and landfills. Although both MPs and NPs can reach the alveolar surface, the latter can pass into the bloodstream, overcoming the pulmonary epithelial barrier. Despite the low reactivity, the number of surface area atoms per unit mass is high in MPs and NPs, greatly enhancing the surface area for chemical reactions with bodily fluids and tissue in direct contact. This is proven in polyvinyl chloride (PVC) and flock workers, who are prone to persistent inflammatory stimulation, leading to pulmonary fibrosis or even carcinogenesis.

scholarly journals A Novel Niosome-Encapsulated Essential Oil Formulation to Prevent Aspergillus flavus Growth and Aflatoxin Contamination of Maize Grains During Storage

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 646 ◽  
Author(s):  
García-Díaz ◽  
Patiño ◽  
Vázquez ◽  
Gil-Serna
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Storage Conditions ◽  
Aflatoxin Contamination ◽  
Small Scale ◽  
Low Concentrations ◽  
Oil Formulation ◽  
Scale Test ◽  
Encapsulation Method

Aflatoxin (AF) contamination of maize is a major concern for food safety. The use of chemical fungicides is controversial, and it is necessary to develop new effective methods to control Aspergillus flavus growth and, therefore, to avoid the presence of AFs in grains. In this work, we tested in vitro the effect of six essential oils (EOs) extracted from aromatic plants. We selected those from Satureja montana and Origanum virens because they show high levels of antifungal and antitoxigenic activity at low concentrations against A. flavus. EOs are highly volatile compounds and we have developed a new niosome-based encapsulation method to extend their shelf life and activity. These new formulations have been successfully applied to reduce fungal growth and AF accumulation in maize grains in a small-scale test, as well as placing the maize into polypropylene woven bags to simulate common storage conditions. In this latter case, the antifungal properties lasted up to 75 days after the first application.

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