Toxicity Effects of Titanium Dioxide Nanoparticles in Marine Algae

Titanium dioxide nanoparticles (TiO2) are mineral compounds that had been manipulated to its nano-scale dimension, approximately 1 to 100nm. Nano-scaled TiO2 are claimed to have better chemical, physical and biological properties which make them enormously applied in industrial manufacturing. However, this has become a big threat to the environment due to the increase disposal of TiO2 into the environment whereby both human and other living organisms could be adversely affected. The aim of this study was to study the effects of TiO2 nanoparticles on two marine microalgae Dunaleilla tertiolecta and Pavlova gyrans. The change in photosynthetic pigments chlorophyll a and carotenoid content was used to measure the response of algae species towards the presence of TiO2 nanoparticle. The results showed Dunaleilla tertiolecta was more susceptible to TiO2 nanoparticles with lower effective concentration of 50% (EC50) at 31.25 mg/L compared to Pavlova gyrans. In addition, TiO2 was found to aggregate and adsorb on algal membrane and reduced its motility. In conclusion, TiO2 nanoparticles caused an impactful effect to the ecosystem and the post production wastes should be managed appropriately

Application of Biochar as Functional Material for Remediation of Organic Pollutants in Water: An Overview

In recent years, numerous studies have focused on the use of biochar as a biological material for environmental remediation due to its low-cost precursor (waste), low toxicity, and diversity of active sites, along with their facile tailoring techniques. Due to its versatility, biochar has been employed as an adsorbent, catalyst (for activating hydrogen peroxide, ozone, persulfate), and photocatalyst. This review aims to provide a comprehensive overview and compare the application of biochar in water remediation. First, the biochar active sites with their functions are presented. Secondly, an overview and summary of biochar performance in treating organic pollutants in different systems is depicted. Thereafter, an evaluation on performance, removal mechanism, active sites involvement, tolerance to different pH values, stability, and reusability, and an economic analysis of implementing biochar for organic pollutants decontamination in each application is presented. Finally, potential prospects to overcome the drawbacks of each application are provided

Maintenance vitamin D3 dosage requirements in Chinese women with post menopausal osteoporosis living in the tropics

Background and Objectives: Vitamin D3 (cholecalciferol) dose required to maintain sufficiency in non- Caucasian women with postmenopausal osteoporosis (PMO) inthe tropics has not been well studied. Some guidelines mandate 800-1000 IU vitamin D/day but the Endocrine Society (US) advocates 1500-2000 IU/day to maintain 25-hydroxyvitamin-D (25(OH)D) concentration at > 75 nmol/L. We aimed to establish oral cholecalciferol dose required to maintain 25(OH)D concentration at > 75 nmol/L in PMO Chinese Malaysian women, postulating lower dose requirements amongst light-skinned subjects in the tropics. Methods and Study Design: 90 Chinese Malaysian PMO women in Kuala Lumpur, Malaysia (2°30'N) with baseline serum 25(OH)D levels ≥ 50 nmol/L were recruited. Prior vitamin D supplements were discontinued and subjects randomized to oral cholecalciferol 25,000 IU/4-weekly (Group-A) or 50,000 IU/4-weekly (Group- B) for 16 weeks, administered under direct observation. Serum 25(OH)D, PTH, serum/urinary calcium were measured at baseline, 8 and 16 weeks. Results: Baseline characteristics, including osteoporosis severity, sun exposure (~3 hours/week), and serum 25(OH)D did not differ between treatment arms. After 16 weeks, 91% of women sufficient at baseline, remained sufficient on 25,000 IU/4-weekly compared with 97% on 50,000 IU/4-weekly with mean serum 25(OH)D 108.1±20.4 and 114.7±18.4 SD nmol/L respectively (p=0.273). At trial's end, 39% and 80% of insufficient women at baseline attained sufficiency in Group A and Group B (p=0.057). Neither dose was associated with hyperparathyroidism or toxicity. Conclusions: Despite pretrial vitamin D supplementation and adequate sun exposure, 25.6% Chinese Malaysian PMO women were vitamin D insufficient indicating sunshine alone cannot ensure sufficiency in the tropics. Both ~900 IU/day and ~1800 IU/day cholecalciferol can safely maintain vitamin D sufficiency in > 90% of Chinese Malaysian PMO women. Higher doses are required with baseline concentration < 75 nmol/L