Risk factors of musculoskeletal disorders (MSD) among palm oil mill workers

The palm oil industry is the fourth largest contributor to the Malaysian Gross National Income (GNI) but the importance of this industry to the nation’s economy does not preclude them from the risk of being affected by the occurrence of musculoskeletal disorders (MSD) among the workers in palm oil mills. Previous studies carried out have not properly explained the exact reasons for the occurrence of musculoskeletal disorders (MSD) among the palm oil mill workers. Thus, this study aim to determine the association between risk factors and MSD among palm oil mill workers. A total of 120 male workers were consecutively enrolled in this crosssectional study. Information on sociodemographic, working, lifestyle, health and injury factors were collected via questionnaire and face-to-face interviews. A high lifetime prevalence of MSD (71.7 percent) among palm oil mill workers was found. However, the one-year prevalence of MSD among the same population was only 50.8 percent. Logistic regression analysis adjusted for age, Body Mass Index (BMI) and smoking revealed that the risk factors: history of previous injury [2.35, 95 percent CI 1.12-4.93], Osteoarthritis [3.9, 95 percent CI 1.568-9.708] and perception of exertion [8.09, 95 percent CI 1.358-48.170] was found to be significantly associated with MSD symptoms reported in the past 12 months. As a conclusion, exposure to the combination of these risk factors may lead to an increased risk of developing MSD among palm oil mill workers

Water Network Optimization with Wastewater Regeneration Models

The conventional water network synthesis approach greatly simplifies wastewater treatment units by using fixed recoveries, creating a gap for their applicability to industrial processes. This work describes a unifying approach combining various technologies capable of removing all the major types of contaminants through the use of more realistic models. The following improvements are made over the typical superstructure-based water network models. First, unit-specific shortcut models are developed in place of the fixed contaminant removal model to describe contaminant mass transfer in wastewater treatment units. Shortcut wastewater treatment cost functions are also incorporated into the model. In addition, uncertainty in mass load of contaminants is considered to account for the range of operating conditions. Furthermore, the superstructure is modified to accommodate realistic potential structures. We present a modified Lagrangean-based decomposition algorithm in order to solve the resulting nonconvex mixed-integer nonlinear programming (MINLP) problem efficiently. Several examples are presented to illustrate the effectiveness and limitations of the algorithm for obtaining the global optimal solutions.The authors would like to acknowledge financial support from the National Science Foundation for financial support under grant CBET-1437668, the program “Estancias de movilidad en el extranjero “Jose Castillejo” para jóvenes doctores” (JC2011-0051) of the Spanish Ministerio de Educación, and from the University of Alicante (GRE11-19)

Hydrothermal Synthesis of Cr2Se3 Hexagons for Sensitive and Lowlevel Detection of 4-Nitrophenol in Water

We report a simple hydrothermal method used for the synthesis of Cr2Se3 hexagons (h-Cr2Se3) and its application towards electrochemical sensing of 4-nitrophenol (4-NP). The formation of h-Cr2Se3 was confrmed by using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray difraction, and X-ray photoelectron spectroscopy. The electrochemical activity of the h-Cr2Se3 modifed screen-printed carbon electrode (SPCE) towards 4-NP was studied using cyclic voltammetry (CV) and amperometric i-t techniques. Typically,the obtained results were compared with those for a bare SPCE. The CV result clearly reveals that h-Cr2Se3 modifed SPCE has higher catalytic activity towards reduction of 4-NP than bare SPCE. Hence, h-Cr2Se3 modifed SPCE was concluded as a viable sensor for sensitive determination of 4-NP. Under optimized conditions, h-Cr2Se3 modifed SPCE demonstrates the excellent capacity to detect the 4-NP in a linear range from 0.05µM to 908.0µM. The LOD and sensitivity in detection of 4-NP were determined at 0.01µM and 1.24µAµM−1 cm−2 respectively. The sensor is highly selective and stable and shows reproducible recovery of 4-NP in domestic supply and river water samples

A novel Laccase biosensor based on laccase immobilized graphene-cellulose microfiber composite modified screen-printed carbon electrode for sensitive determination of catechol

© The Author(s) 2017. In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuIIfor laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA-1 cm-2, 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea