Inhalation of respirable and inhalable particles has been known to cause occupational lung disease such as pneumoconiosis and asbestosis. The study investigates the dispersion behaviour, density and particle size of aerosols mist bigger than 10 µm (PM10) consist of distilled water (control) or CNF 2 %w/v aqueous suspension by simulating a benchtop personal breathing zone of 60 x 60 x 60 cm. The magnesium oxide (MgO) coated slide was used to determine the dispersion and size of the water droplet. Non-coated glass slide was used to collect CNF from the water droplets for the examination under FESEM to verify the nano-morphology and nano-size. The examination of the MgO coated slides showed the distilled water with or without CNF were capable to disperse up to 30 cm radius horizontally within 5 minutes when the aerosol was vertically discharged upward approx. 30 cm height at the rate of 1 ml/min. The distilled water and CNF aqueous suspension produced aerosol mist that contained water droplet with size above PM10 varying between 11 to 35 µm at the radius distance of 10, 20 and 30 cm. The examination under FESEM found the nanofibrous morphology and nano dimension of approximately 12 nm in both specimens of the plain glass slide and CNF 2 %w/v aqueous suspension. The size of the water droplet with CNF is still categorized as the inhalable particulate matter, thus there is a need to determine whether the CNF could be deposited in the respiratory system and cause damage.
Cellulose

Introduction: Melatonin (MEL) loaded alginate-chitosan/beta-tricalcium phosphate (Alg-CH/β-TCP) composite hydrogel has been formulated as a scaffold for bone regeneration. MEL in the scaffold was anticipated to accelerate bone regeneration. The objective of this study is to observe signs of systemic toxicity and physical changes on surface defected bone for bone regenerative performance of the composite. Methods: The proximal-medial metaphyseal cortex of the left tibia of New Zealand white rabbit was the surgical site of the defect. A total of nine rabbits were randomly allocated to three groups; Group I; implanted with MEL loaded Alg-CH/β-TCP, Group II; Alg-CH/β-TCP and Group III defects were sham control. The rabbits were daily observed to determine systemic toxicity effects by composites. The physical changes to implanted site were observed using digital x-ray radiography and computerized tomography at weeks 0, 2, 4, 6 and 8 of post-implantation. Results: There were no clinical signs of systemic toxicity for all groups of rabbits. Digital radiography did not show adverse effects to the bone. Computerized tomography showed reduction in the area size and depth volume of the implantation site, but accelerated regeneration within the 8 weeks was not significantly different (P<0.05) between the groups. Conclusion: Overall, the study suggests that Alg-CH/β-TCP composite scaffolds with and without the addition of MEL are compatible to bone. The composite scaffolds reduced the area size and depth volume of the implanted site within the 8-week duration. However, no remarkable difference in the accelerated reduction of area size and depth volume was observed.