Protective Wax Research Articles

Fabrication of thermoelectric gas sensors on micro-hotplates

We present a series of fabrication processes of high-performance thermoelectric gas sensor micro-devices including a membrane–releasing process in KOH for the mass production of hot-plate type membrane devices. The fabricated devices are hydrogen gas sensors based on the thermoelectric detection of the catalytic hydrogen combustion. The KOH wet etching membrane–releasing process, using protective wax or polymer coating shows fabrication yields of over 70% and 80%. Most sensors detect wide range hydrogen concentration from several part-per-million, ppm, to percent in air demonstrating robust sensor process. As the device working principle of the Seebeck effect is linear phenomena, a good linear relationship between voltage signal and hydrogen concentration can be achieved, 1 mV = 1000 ppm, down to 50 ppm hydrogen in air. The test method for a large number of sensor devices has been developed, and the validation study for mass production of gas sensors is carried out.

Forensic differentiation of biogenic organic compounds from petroleum hydrocarbons in biogenic and petrogenic compounds cross-contaminated soils and sediments

“Total petroleum hydrocarbons” (TPHs) or “petroleum hydrocarbons” (PHCs) are one of the most widespread soil pollutants in Canada, North America, and worldwide. Clean-up of PHC-contaminated soils and sediments costs the Canadian economy hundreds of million of dollars annually. Much of this activity is driven by the need to meet regulated levels of PHC in soil. These PHC values are legally required to be assessed using standard methods. The method most commonly used in Canada, specified by the Canadian Council of Ministers of the Environment (CCME), measures the total hydrocarbon concentrations in a soil by carbon range (Fraction 1: C 6–C 10; Fraction 2: C 10–C 16, Fraction 3: C 16–C 34: and Fraction 4: C 34+). Using the CCME method, all of the materials extractible by a mixture of 1:1 hexane:acetone are considered to be petroleum hydrocarbon contaminants. Many hydrocarbon compounds and other extractible materials in soil, however, may originate from non-petroleum sources. Biogenic organic compounds (BOCs) is a general term used to describe a mixture of organic compounds, including alkanes, sterols and sterones, fatty acids and fatty alcohols, and waxes and wax esters, biosynthesized by living organisms. BOCs are also produced during the early stages of diagenesis in recent aquatic sediments. BOC sources could include vascular plants, algae, bacteria and animals. Plants and algae produce BOCs as protective wax coating that are released back into the sediment at the end of their life cycle. BOCs are natural components of thriving plant communities. Many solvent-extraction methods for assessing soil hydrocarbons, however, such as the CCME method, do not differentiate PHCs from BOCs. The naturally occurring organics present in soils and wet sediments can be easily misidentified and quantified as regulated PHCs during analysis using such methods. In some cases, biogenic interferences can exceed regulatory levels, resulting in remediation of petroleum impacts that are not actually present. Consequently, reliance on these methods can trigger unnecessary and costly remediation, while also wasting valuable landfill space. Therefore, it is critically important to develop new protocols to characterize and differentiate PHCs and BOCs in contaminated sediments. In this study, a new reliable gas chromatography–mass spectrometry (GC–MS) method, in combination with a derivatization technique, for characterization of various biogenic compounds (including biogenic alkanes, sterols, fatty acids and fatty alcohols) and PHCs in the same sample has been developed. A multi-criteria approach has been developed to positively identify the presence of biogenic compounds in soil and sediment samples. More than thirty sediment samples were collected from city stormwater management (SWM) ponds and wetlands across Canada. In these wet sediment samples, abundant biogenic n-alkanes, thirteen biogenic sterols, nineteen fatty carboxylic acids, and fourteen fatty alcohols in a wide carbon range have been positively identified. Both PHCs and BOCs in these samples were quantitatively determined. The quantitation data will be used for assessment of the contamination sites and toxicity risks associated with the CCME Fraction 3 hydrocarbons.

Use of Arabidopsis eceriferum Mutants to Explore Plant Cuticle Biosynthesis

The plant cuticle is a waxy outer covering on plants that has a primary role in water conservation, but is also an important barrier against the entry of pathogenic microorganisms. The cuticle is made up of a tough crosslinked polymer called "cutin" and a protective wax layer that seals the plant surface. The waxy layer of the cuticle is obvious on many plants, appearing as a shiny film on the ivy leaf or as a dusty outer covering on the surface of a grape or a cabbage leaf thanks to light scattering crystals present in the wax. Because the cuticle is an essential adaptation of plants to a terrestrial environment, understanding the genes involved in plant cuticle formation has applications in both agriculture and forestry. Today, we'll show the analysis of plant cuticle mutants identified by forward and reverse genetics approaches.

Use of Arabidopsis eceriferum Mutants to Explore Plant Cuticle Biosynthesis

The plant cuticle is a waxy outer covering on plants that has a primary role in water conservation, but is also an important barrier against the entry of pathogenic microorganisms. The cuticle is made up of a tough crosslinked polymer called "cutin" and a protective wax layer that seals the plant surface. The waxy layer of the cuticle is obvious on many plants, appearing as a shiny film on the ivy leaf or as a dusty outer covering on the surface of a grape or a cabbage leaf thanks to light scattering crystals present in the wax. Because the cuticle is an essential adaptation of plants to a terrestrial environment, understanding the genes involved in plant cuticle formation has applications in both agriculture and forestry. Today, we'll show the analysis of plant cuticle mutants identified by forward and reverse genetics approaches.

Pruning of host plant neighbours as defence against enemy ant invasions: Crematogaster ant partners of Macaranga protected by "wax barriers" prune less than their congeners.

Many ant partners of tropical ant-plants prune the leaves and shoot tips of other plants growing around their hosts. According to the hypothesis proposed by Davidson et al. (Ecology 69:801-808), this specialized behaviour not only protects the host plants against overgrowth, but it also conveys a direct benefit to the ant colony as it removes contact points to the neighbouring vegetation where invasions of enemy ants could occur. Here we test this hypothesis by comparing pruning intensity in five closely related Crematogaster (subgenus Decacrema) plant-ant species (and one species of Technomyrmex) that differ in their exposure to competition by other ants. Pruning intensity was quantified by measuring the area loss of paper tape pieces wrapped around the stems of Macaranga host plants. All Crematogaster (Decacrema) ants tested but not Technomyrmex sp. pruned, but the intensity of the behaviour varied strongly between and within species. Pruning was significantly weaker in the three tested Crematogaster species inhabiting Macaranga host plants with a slippery, waxy stem surface, which functions as a mechanical barrier protecting the specific ant partners against generalist competitors. Pruning was generally stronger on more densely ant-populated trees. Even though the number of ants per twig length was lower in associations of ants with glaucous Macaranga hosts, only part of the variation of pruning activity could be explained by "ant density". When corrected for ant density, "wax-running" Crematogaster (Decacrema) ants still pruned more weakly than their congeners inhabiting non-glaucous Macaranga hosts. Pruning is obviously most important when an ant-plant is potentially accessible to intruders, but less necessary when the ant colony is isolated by a protective wax barrier. Our results support the hypothesis that "selfish" defence against invasions is the major selective pressure that has led to the development and maintenance of pruning behaviour in weakly competitive plant-ants.

X-ray reflectivity and grazing incidence diffraction studies of the adhesion of protective wax coatings on metal surfaces

More than 50 years after the introduction of water displacing petroleum additives for corrosion protection, scientists are still trying to understand how and why they work. This paper continues research on corrosion preventatives used on objects in museum custody using synchrotron radiation techniques to assess the thickness and organization of the protective layers of corrosion preventative. The organization of sodium dodecylsulphate on aluminium, zinc and platinum surfaces has been studied. As well, preliminary in situ experiments using synchrotron radiation have been undertaken on electrode processes in an electrochemical cell using platinum electrodes and a sodium sulphate solution at different applied potentials.

Improving the Quality of Zv-P Protective Wax

Improving the Quality of Zv-P Protective Wax

Adaptations in scale insects.

Many unusual features of scale insects (Hemiptera: Coccoidea) can be explained as historical legacy. Developmental specializations in ancestral coccoids resulted in a neotenous adult female and a drastic metamorphosis of the male. Subsequent evolution led to numerous, often convergently derived, adaptations to parasitic life on higher plants. The sedentary lifestyle of female scale insects has favored the evolution of appendage reduction or loss, gross changes in body shape, and protective wax secretions, tests, and other scale covers. Morphological peculiarities of adult males relate to flight or to mating with concealed females. Scale insects have diverse egg-protecting methods, a range of chromosome behaviors (including several methods of sex determination), marked sexual dimorphism [even sometimes in first-instar nymphs (crawlers)], and more rarely sexual dichronism. Crawlers have evolved as the main agents of dispersal. The biotic interactions of scale insects include diverse endosymbioses with microorganisms, sometimes morphological and behavioral adaptations for obligate association with ants, and often highly specific host-plant associations that may lead to demic adaptation or the evolution of complex galls.

Fine Structural Aspects of Cotton Fiber Attachment to the Seed Coat: Morphological Factors Affecting Saw Ginning of Lint Cotton

We analyzed cytological aspects of fiber attachment and the effect of hand and saw ginning with transmission and low-temperature electron microscopy At the junction of the lint fiber to the seed coat surface there is an angular region or elbow, containing thick primary cell-wall material that apparently adds to the strength of fiber attachment to the seed coat. A protective wax layer covers the entire seed coat surface and is continuous along the surface of all fibers. Removal of full-length lint fibers during saw ginning results in a clean separation from the wax layer and primary wall just above the elbow junction, as occurs with hand ginning. Separation can be by cutting, in which case secondary cell wall is severed at the seed coat surface, or by pulling away of the intact fiber along with secondary cell-wall material present in the shank region of the fiber cell. These findings indicate that improving the yield of full-length lint fibers during saw ginning may require pretreatments to loosen the cell-wall structure at the neck region. This may involve partial dissolution of the cuticular wax layer on the fiber to improve penetration of any aqueous pretreatment(s).

Separation of hydrocarbons in protective wax by means of CaA zeolite

Separation of hydrocarbons in protective wax by means of CaA zeolite