Properties of Poly(Vinyl Alcohol)/Chitosan Nanocomposite Films Reinforced with Oil Palm Empty Fruit Bunch Amorphous Lignocellulose Nanofibers

The objective of this study was to investigate the properties of poly(vinyl alcohol)/chitosan nanocomposite films reinforced with different concentration of amorphous LCNFs. The properties analyzed were morphological, physical, chemical, thermal, biological, and mechanical characteristics. Oil palm empty fruit bunch LCNFs obtained from multi-mechanical stages were more dominated by amorphous region than crystalline part. Varied film thickness, swelling degree, and transparency of PVA/chitosan nanocomposite films reinforced with amorphous part were produced. Aggregated LCNFs, which reinforced PVA/chitosan polymer blends, resulted in irregular, rough, and uneven external surfaces as well as protrusions. Based on XRD analysis, there were two or three imperative peaks that indicated the presence of crystalline states. The increase in LCNFs concentration above 0.5% to PVA/chitosan polymer blends led to the decrease in crystallinity index of the films. A noticeable alteration of FTIR spectra, which included wavenumber and intensity, was obviously observed along with the inclusion of amorphous LCNFs. That indicated that a good miscibility between amorphous LCNFs and PVA/chitosan polymer blend generated chemical interaction of those polymers during physical blending. Reinforcement of PVA/chitosan polymer blends with amorphous LCNFs influenced the changes of T_g (glass transition temperature), T_m (melting point temperature), and T_max (maximum degradation temperature). Three thermal phases of PVA/chitosan/LCNFs nanocomposite films were also observed, including absorbed moisture evaporation, PVA and chitosan polymer backbone structural degradation and LCNFs pyrolysis, and by-products degradation of these polymers. The addition of LCNFs 0.5% had the highest tensile strength and the addition of LCNFs above 0.5% decreased the strength. The incorporation of OPEFB LCNFs did not show anti-microbial and anti-fungal properties of the films. The addition of amorphous LCNFs 0.5% into PVA/chitosan polymer blends resulted in regular and smooth external surfaces, enhanced tensile strength, increased crystallinity index, and enhanced thermal stability of the films.     

Coffee,its roasted form,and their residues cause birth failure and shorten lifespan in dengue vectors

Environmental Science and Pollution Research - In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore,...     

Tualang honey supplementation improves oxidative stress status among chronic smokers

Free radicals induced by cigarette smoking have been linked to an increase in oxidative stress resulting in smoking-related cardiovascular diseases. However, the possible effect of honey that has antioxidant property in improving oxidative stress status among smokers has not yet been reported. Hence, this study was to determine the effects of 12-week Tualang honey supplementation on F₂-isoprostanes, superoxide dismutase, glutathione peroxidase, catalase, and total antioxidant status among chronic smokers. A total of 32 non-smokers and 64 chronic smokers were recruited from Quit Smoking Clinic and Health Campus, Universiti Sains, Malaysia. Smokers were randomized into two groups (n = 32/group) namely smokers without supplementation and smokers with honey supplementation (20 g/day) for 12 weeks. Blood was obtained from non-smokers and smokers at pre-intervention and from smokers at post-intervention. During pre-intervention, the levels/activity of F₂-isoprostanes, total antioxidant status, and catalase were significantly higher while superoxide dismutase and glutathione peroxidase were lower in smokers than non-smokers. During post-intervention, in supplemented smokers, there were significant decrease in F₂-isoprostanes and increase in total antioxidant status, glutathione peroxidase and catalase levels/activities compared with pre-intervention. This study indicates that honey supplementation improves oxidative stress status suggesting a beneficial role of honey in reducing the risk of cardiovascular diseases.     

Research trends in biodiversity loss: a bibliometric analysis

Environmental Science and Pollution Research - Although increased attempts to preserve biodiversity ecosystems have been widely publicized, bibliometric research of biodiversity loss remains...     

The Relation Between Upper Limb Muscle and Brain Activity in Two Precision Levels of Repetitive Light Tasks

A study was conducted to investigate the effects of repetitive light tasks of low and high precision on upper limb muscles and brain activities. Surface electromyography (EMG) and electroencephalography (EEG) were used to measure the muscle and brain activity of 10 subjects. The results show that the root-meansquare (RMS) and mean power frquency (MPF) of the muscle activity and the mean power of the EEG alpha bands were higher on the high-precision task than on the low-precision one. There was also a high and significant correlation between upper limb muscle and brain activity during the tasks. The longer the time and the more precise the task, the more the subjects become fatigued both physically and mentally. Thus, these results could be potentially useful in managing fatigue, especially fatique related to muscle and mental workload.     

Evaluation of the giant reed (Arundo donax) in horizontal subsurface flow wetlands for the treatment of dairy processing factory wastewater

Two emergent macrophytes, Arundo donax and Phragmites australis, were established in experimental horizontal subsurface flow (HSSF), gravel-based constructed wetlands (CWs) and challenged by treated dairy processing factory wastewater with a median electrical conductivity of 8.9 mS cm(-1). The hydraulic loading rate was tested at 3.75 cm day(-1). In general, the plants grew well during the 7-month study period, with no obvious signs of salt stress. The major water quality parameters monitored (biological oxygen demand (BOD), suspended solids (SS) and total nitrogen (TN) but not total phosphorus) were generally improved after the effluent had passed through the CWs. There was no significance different in removal efficiencies between the planted beds and unplanted gravel beds (p?>?0.007), nor was there any significant difference in removal efficiencies between the A. donax and P. australis beds for most parameters. BOD, SS and TN removal in the A. donax and P. australis CWs was 69, 95 and 26 % and 62, 97 and 26 %, respectively. Bacterial removal was observed but only to levels that would allow reuse of the effluent for use on non-food crops under Victorian state regulations. As expected, the A. donax CWs produced considerably more biomass (37?±?7.2 kg wet weight) than the P. australis CWs (11?±?1.4 kg wet weight). This standing crop equates to approximately 179 and 68 tonnes ha(-1) year(-1) biomass (dry weight) for A. donax and P. australis, respectively (assuming a 250-day growing season and single-cut harvest). The performance similarity of the A. donax and P. australis planted CWs indicates that either may be used in HSSF wetlands treating dairy factory wastewater, although the planting of A. donax provides additional opportunities for secondary income streams through utilisation of the biomass produced.     

Assessment of trace metals using lichen transplant from automobile mechanic workshop in Ile-Ife metropolis,Nigeria

The level of air pollution around the automobile mechanic workshops has been generally overlooked. This study, examined the level of trace metals in automobile mechanic workshops and the suitability of using transplanted lichen thalli of Lepraria incana for measuring air pollution in such areas. Samples of the lichen thalli were transplanted into seven different sites and were attached to the bark of trees at each site. The samples were harvested from the sites after 3-month exposure. Concentrations of Pb, Cu, Cd, Fe, Zn, and S content were determined using an atomic absorption spectrophotometer. Results showed that there was a significant difference in the trace metals concentrations across the sites (p?<?0.05). The analyzed lichen samples showed a range of 91.26–119.35 ppm for Fe, 30.23–61.32 ppm for Zn, 1.25–2.45 ppm for Cu, 0.017–0.043 ppm for Cd, 0.018–0.051 ppm, and 0.37–0.42 ppm for S. From the study, sites 6 and 7 presented higher concentrations of Cd, Pb, and Zn than other sites. The enrichment factor calculated showed that Zn, Cd, and Pb were greatly enriched from the workshops. The trend in the concentration of these heavy metals suggests that activities in these workshops might become a major source of certain heavy metals in the environment and if the pollution activities persist, it might become worrisome over time.     

Preparation and characterization of glass hollow fiber membrane for water purification applications

This work discusses the preparation and characterizations of glass hollow fiber membranes prepared using zeolite-5A as a starting material. Zeolite was formed into a hollow fiber configuration using the phase inversion technique. It was later sintered at high temperatures to burn off organic materials and change the zeolite into glass membrane. A preliminary study, that used thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared (FTIR), confirmed that zeolite used in this study changed to glass at temperatures above 1000 °C. The glass hollow fiber membranes prepared using the phase inversion technique has three different microstructures, namely (i) sandwich-like structure that originates from inner layer, (ii) sandwich-like that originates from outer layer, and (iii) symmetric sponge like. These variations were influenced by zeolite weight loading and the flow rate of water used to form the lumen. The separation performances of the glass hollow fiber membrane were studied using the pure water permeability and the rejection test of bovine serum albumin (BSA). The glass hollow fiber membrane prepared from using 48 wt% zeolite loading and bore fluid with 9 mL min^?1 flow rate has the highest BSA rejection of 85% with the water permeability of 0.7 L m^?2 h^?1 bar^?1. The results showed that the separation performance of glass hollow fiber membranes was in the ultrafiltration range, enabled the retention of solutes with molecular sizes larger than 67 kDa such as milk proteins, endotoxin pyrogen, virus, and colloidal silica.