Study on Awareness on the Mercury Usage in Sri Lankan Small Scale Jewellery Sector

Mercury is utilised in extensive amounts for gold recovery from the waste produced during the traditional gold jewellery manufacturing particularly in the Small Scale Jewellery Sector (SSJS). Due to its toxicity and bioaccumulation potential this can cause for serious health effects and environmental pollution. Colombo and Gampaha districts are the main two districts where SSJS is mostly confined. Therefore, this study was focused to assess the amount of mercury usage in SSJS through a structured interview and a questionnaire survey among 120 goldsmiths from these districts. It was revealed that, gold is recovered once in a six month period or annually by using significant amounts of mercury which is totally depends on the workload and amount of waste collected.In this process, the waste is mixed with mercury to form Hg-Au amalgam and it is roasted to recover gold while mercury gets removed through vitalisation. It was disclosed that, about 4 g of mercury is used to refine one pound of gold (8 g). None of the respondents practice any safety precautions or proper ventilation techniques during this process. Therefore they get readily exposed to mercury vapor. Among the interviewees, only 10% of manufacturers were aware about the toxicity of mercury and do not use mercury in gold refining process while 20% of the individuals were not aware about the harmful effects of mercury. However, 70% of the respondents were aware about the toxic effects of mercury but use extensively as a rapid way off extracting gold from waste. 90% of the inspected workshops had very poor ventilation facilities thus increase the susceptibility of exposure to mercury vapor. 24% of the respondents store mercury in unsafe plastic bags which can easily get damaged and released into the environment. Approximately 25% of the respondents revealed that they had some health issues after they engaged in gold refining. Therefore biomonitoring assessment is recommended for a better understanding of mercury exposure levels of the people engaged in gold refining in SSJS.Keywords: Gold refining, Mercury, Small scale jewellery secto

Recent Synthetic Studies Leading to Structural Revisions of Marine Natural Products

Because of the highly unique structures of marine natural products, there are many examples of structures that were originally proposed based on spectral analyses but later proven incorrect. In many cases, the total syntheses of the originally proposed structures of marine natural products has confirmed their incorrectness and the subsequent total syntheses of the newly proposed structures proved the revised structures. This review will show such cases appearing after 2005 and demonstrate how the true structures were elucidated

A novel lectin from Agrocybe aegerita shows high binding selectivity for terminal N-acetylglucosamine

A novel lectin was isolated from the mushroom Agrocybe aegerita (designated AAL-2) by affinity chromatography with GlcNAc (N-acetylglucosamine)-coupled Sepharose 6B after ammonium sulfate precipitation. The AAL-2 coding sequence (1224 bp) was identified by performing a homologous search of the five tryptic peptides identified by MS against the translated transcriptome of A. aegerita. The molecular mass of AAL-2 was calculated to be 43.175 kDa from MS, which was consistent with the data calculated from the amino acid sequence. To analyse the carbohydrate-binding properties of AAL-2, a glycan array composed of 465 glycan candidates was employed, and the result showed that AAL-2 bound with high selectivity to terminal non-reducing GlcNAc residues, and further analysis revealed that AAL-2 bound to terminal non-reducing GlcNAc residues with higher affinity than previously well-known GlcNAc-binding lectins such as WGA (wheatgerm agglutinin) and GSL-II (Griffonia simplicifolia lectin-II). ITC (isothermal titration calorimetry) showed further that GlcNAc bound to AAL-2 in a sequential manner with moderate affinity. In the present study, we also evaluated the anti-tumour activity of AAL-2. The results showed that AAL-2 could bind to the surface of hepatoma cells, leading to induced cell apoptosis in vitro. Furthermore, AAL-2 exerted an anti-hepatoma effect via inhibition of tumour growth and prolongation of survival time of tumour-bearing mice in vivo

Hydrogen Storage Materials for Mobile and Stationary Applications: Current State of the Art

One of the limitations to the widespread use of hydrogen as an energy carrier is its storage in a safe and compact form. Herein, recent developments in effective high-capacity hydrogen storage materials are reviewed, with a special emphasis on light compounds, including those based on organic porous structures, boron, nitrogen, and aluminum. These elements and their related compounds hold the promise of high, reversible, and practical hydrogen storage capacity for mobile applications, including vehicles and portable power equipment, but also for the large scale and distributed storage of energy for stationary applications. Current understanding of the fundamental principles that govern the interaction of hydrogen with these light compounds is summarized, as well as basic strategies to meet practical targets of hydrogen uptake and release. The limitation of these strategies and current understanding is also discussed and new directions proposed