Subcritical water extraction (SWE) of Zingiber zerumbet using two level full factorial design

Zingiber zerumbet was reported to has chemo preventive effects and was suggested as one of the therapeutic treatments for cancer. In this study, Z. zerumbet was extracted using subcritical water extraction (SWE) by employing two level full factorial design. 2k full factorial design was employed using 18 runs with 10 repeats in central points. The independent variables factors were temperature (100-150°C), time (10-30 minutes) and material ratio (1:10 and 1:20 g/ml) for the evaluation of highest zerumbone concentration and overall yield of extracted Z. zerumbet. Effects of extraction temperature and time were found to be significant on all responses with p-value <0.05. However, the material ratio only gave significant effect on the zerumbone concentration and less significant on the yield. In addition, the value of curvature was found to be significant, thus indicating the relation between the independent variables and the response was linear. Therefore, it was found that the concentration of zerumbone and yield from Z. zerumbet extracted by SWE were significantly affected by temperature and time of extraction

Potential of membrane technology for treatment and reuse of water from old mining lakes

The El-Nino phenomenon in early 2014 contributed to the lack of water supply in most Southeast Asian countries. Suggestions have since been made to ensure the continuity of water supply, one of which involves membrane technology to treat mine water so that it is compatible for citizens’ use. Accordingly, the objective of this research was to study the efficiency of membrane technology in treating mine water. Our elucidation of all the parameters has showed that the best attainable classification is at Class IV. Although it was still regarded as polluted, the treated mine water can be used as water supply reservoir. For the membranes tested such as ultrafiltration 10 kDa, 5 kDa and reverse osmosis, the percentage of rejection for chemical oxygen demand is 21-72%, 40-96% for total suspended solids and 21-72% for ammonia nitrogen. The pH also gradually shifted to almost neutral after the filtration

Do you believe the transformational leader's role in engaging employees at the workplace? An evidence in Malaysia

Leadership style is one of the factors that cause employees' unhappiness while working. Ineffective leadership among the leaders nowadays may affect the work engagement of employees in an organization. Thus, this research objective is to investigate the relationship between transformational leadership and work engagement among workers in one government linked company located at the southern region of Malaysia. To obtain the empirical data, 108 clerical staff of the studied company were involved as the participant of the study. A survey research design by using a questionnaire adapted from Multiple Leadership Questionnaire acquired by Bass (1985) and the Utrecht Work Engagement Scale (UWES) was employed for the data collection method. Then, all findings were analyzed by using the descriptive and structural Equation Modelling (SEM) with SmartPLS 3 software. Hence, the result showed that there is a positive and significant relationship between transformational leadership and work engagement among the studied company. Lastly, the researchers have provided some recommendations for the organization and future research

A comparative study on zerumbone concentration, radical scavenging activity and total phenolic content of zingiber zerumbet extracted via green and conventional extraction

Extraction is crucial for herbal extraction to ensure high quality of bioactive compounds from natural herbs. In the current work, Zingiber Zerumbet was extracted via subcritical water extraction (SWE) and is compared with the conventional solvent extraction, Soxhlet. The quality of the extract was investigated in terms of zerumbone concentration, r adical scavenging activity (RSA) and total phenolic content (TPC). For zerumbone concentration, extraction via SWE gave 19.82 ±0.004 mg/g as compared with Soxhlet; 28.51±0.079 mg/g. However, the extraction time required for SWE to yield such concentration only required 40 minutes instead of Soxhlet which took 480 minutes. The same trend was recorded for RSA, which yielded 60.70±0.070% inhibition for SWE and 68.81±0.024% inhibition from Soxhlet extraction. In contrast to TPC, SWE recorded a higher response than Soxhlet extraction, which was 19.19±0.003 mgGAE/g DW, while Soxhlet; 8.30±0.019 mgGAE/g DW. Therefore, the SWE method is more favorable for obtaining a higher value of TPC, slightly good in antioxidant properties but lower zerumbone concentration value than organic solvent extraction. However, the reduced extraction time was almost 12 times quicker for SWE when compared with Soxhlet extraction. Overall, SWE is a promising alternative environmentally friendly since it only uses water as solvent and is co mparable to the conventional method

Insights into the neuropathology of cerebral ischemia and its mechanisms

Cerebral ischemia is a result of insufficient blood flow to the brain. It leads to limited supply of oxygen and other nutrients to meet metabolic demands. These phenomena lead to brain damage. There are two types of cerebral ischemia: focal and global ischemia. This condition has significant impact on patient's health and health care system requirements. Animal models such as transient occlusion of the middle cerebral artery and permanent occlusion of extracranial vessels have been established to mimic the conditions of the respective type of cerebral ischemia and to further understand pathophysiological mechanisms of these ischemic conditions. It is important to understand the pathophysiology of cerebral ischemia in order to identify therapeutic strategies for prevention and treatment. Here, we review the neuropathologies that are caused by cerebral ischemia and discuss the mechanisms that occur in cerebral ischemia such as reduction of cerebral blood flow, hippocampal damage, white matter lesions, neuronal cell death, cholinergic dysfunction, excitotoxicity, calcium overload, cytotoxic oedema, a decline in adenosine triphosphate (ATP), malfunctioning of Na+/K+-ATPase, and the blood-brain barrier breakdown. Altogether, the information provided can be used to guide therapeutic strategies for cerebral ischemia

Modeling and optimization of pilot-scale subcritical water extraction on Zingiber zerumbet by central composite design

Zingiber zerumbet (Z. zerumbet) or locally called 'lempoyang' is one of the ginger species extensively cultivated and utilized in the Southeast Asia region. In order to extract valuable ingredients from Z. zerumbet, a green and non-toxic extraction process is implemented namely subcritical water extraction (SWE). Modeling and optimization of SWE of Z. zerumbet are performed using the central composite design (CCD) by 20 runs with 6 repetitions at the center point. The independent variables investigated in this research are temperature (130-170°C), time of extraction (20-40 minutes) and solid to solvent ratio (20-40 ml/g) that focused to identify the optimized process parameters for zerumbone concentration, antioxidant activity, and yield of extracts. All independent variables researched were analyzed to be significant as the p-value for zerumbone concentration, antioxidant activity and yield are 0.0001, which are less than 0.05 for a model to be significant. The optimum process parameters for all responses of Z. zerumbet extract are at 170°C, 20 minutes and 20 ml/g. This optimum condition was validated and the correlation between predicted and experimental values was within 95% which indicated the range of variables selected was valid. Thus, the outcome from this research may be beneficial on subcritical water extraction of ginger species especially Z. zerumbet