In Situ Coatings of Polymeric Films with Core Polystyrene, Core-Shell Polystyrene/SiO2, and Hollow SiO2 Micro/Nanoparticles and Potential Applications

In many industrial settings, films of polymers such as polypropylene (PP) and polyethylene terephthalate (PET) require surface treatment due to poor wettability and low surface energy. Here, a simple process is presented to prepare durable thin coatings composed of polystyrene (PS) core, PS/SiO₂ core-shell, and hollow SiO₂ micro/nanoparticles onto PP and PET films as a platform for various potential applications. Corona-treated films were coated with a monolayer of PS microparticles by in situ dispersion polymerization of styrene in ethanol/2-methoxy ethanol with polyvinylpyrrolidone as stabilizer. A similar process on untreated polymeric films did not yield a coating. PS/SiO₂ core-shell coated microparticles were produced by in situ polymerization of Si(OEt)₄ in ethanol/water onto a PS-coated film, creating a raspberry-like morphology with a hierarchical structure. Hollow porous SiO₂-coated microparticles onto a PP/PET film were formed by in situ dissolution of the PS core of the coated PS/SiO₂ particles with acetone. The coated films were characterized by E-SEM, FTIR/ATR, and AFM. These coatings may be used as a platform for various applications, e.g. magnetic coatings onto the core PS, superhydrophobic coatings onto the core-shell PS/SiO₂, and solidification of oil liquids within the hollow porous SiO₂ coating.

Cumulative effects of natural and anthropogenic disturbances on the forest carbon balance in the oil sands region of Alberta, Canada; a pilot study (1985-2012)

BACKGROUND

Assessing cumulative effects of anthropogenic and natural disturbances on forest carbon (C) stocks and fluxes, because of their relevance to climate change, is a requirement of environmental impact assessments (EIAs) in Canada. However, tools have not been developed specifically for these purposes, and in particular for the boreal forest of Canada, so current forest C assessments in EIAs take relatively simple approaches. Here, we demonstrate how an existing tool, the Generic Carbon Budget Model (GCBM), developed for national and international forest C reporting, was used for an assessment of the cumulative effects of anthropogenic and natural disturbances to support EIA requirements. We applied the GCBM to approximately 1.3 million ha of upland forest in a pilot study area of the oil sands region of Alberta that has experienced a large number of anthropogenic (forestry, energy sector) and natural (wildfire, insect) disturbances.

RESULTS

Over the 28 years, 25% of the pilot study area was disturbed. Increasing disturbance emissions, combined with declining net primary productivity and reductions in forest area, changed the study area from a net C sink to a net C source. Forest C stocks changed from 332.2 Mt to 327.5 Mt, declining by 4.7 Mt at an average rate of 0.128 tC ha^-1 yr^-1. The largest cumulative areas of disturbance were caused by wildfire (139,000 ha), followed by the energy sector (110,000 ha), insects (33,000 ha) and harvesting (31,000 ha) but the largest cumulative disturbance emissions were caused by the energy sector (9.5 Mt C), followed by wildfire (5.5 Mt C), and then harvesting (1.3 Mt C).

CONCLUSION

An existing forest C model was used successfully to provide a rigorous regional cumulative assessment of anthropogenic and natural disturbances on forest C, which meets requirements of EIAs in Canada. The assessment showed the relative importance of disturbances on C emissions in the pilot study area, but their relative importance is expected to change in other parts of the oil sands region because of its diversity in disturbance types, patterns and intensity. Future assessments should include peatland C stocks and fluxes, which could be addressed by using the Canadian Model for Peatlands.

Wound patterns: detection, documentation and analysis

Bruises and other injuries located in skin can play a valuable role in the forensic investigation of a crime. This paper present details outlining how forensic odontology can be useful in detecting, documenting and analyzing such patterned injuries. In addition, four illustrated case histories are included.

The detection and documentation of trace wound patterns by use of an alternative light source

This article is a discussion of the use of narrow-band light sources coupled with cameras equipped with band-pass filters to document patterned injuries on human skin. Several case reports are included.

Basosquamous carcinoma of the head and neck

Clinical experience with two cases of basosquamous are described. Wide surgical excision is the preferred method of treatment. In some cases, however, radiation therapy or chemotherapy may be useful treatment adjuncts. Unfortunately, prognosis is poor.