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Process conditions for the manufacture of highly micro-mesoporous eco-friendly activated carbon from artocarpus integer bio-waste by steam activation
No full textIn this paper, for the first time, we report the process conditions to obtain highly micro-mesoporous eco-friendly activated carbon (Eco-AC) from Artocarpus integer bio-waste by steam activation. The proposed novel material provides a green alternative to existing chemically activated bio-wastes for the preparation of highly micro-mesoporous activated carbon. The influences of pyrolysis temperature and duration followed by steam-gasification temperature and duration on the pore structure and yield of Eco-ACs were explored in this study. The prepared Eco-ACs had been characterized by N2 adsorption-desorption analysis and FESEM. Based on our experimental results, the optimum technology conditions for preparing highly micro-mesoporous Eco-AC are: pyrolysis temperature, 700 °C; pyrolysis duration, 60 min; steam-gasification temperature, 750 °C; and steam-gasification duration, 60 min. The optimal Eco-AC has a BET surface area of 852.63 m2/g, Langmuir surface area of 964.79 m2/g, t-plot micropore surface area of 506.03 m2/g, t-plot mesopore surface area of 346.60 m2/g, total pore volume of 0.632 cm3/g, BET average pore diameter of 2.967 nm and BJH average pore diameter of 5.489 nm with a reasonable yield, 33.5%, making it a promising economical and eco-friendly carbon material for use in environmental separation technologies and water treatment
Characterization of a novel N-acylhomoserine lactonase, AidP, from Antarctic Planococcus sp.
No full textBACKGROUND: N-acylhomoserine lactones (AHLs) are well-studied signalling molecules produced by some Gram-negative Proteobacteria for bacterial cell-to-cell communication or quorum sensing. We have previously demonstrated the degradation of AHLs by an Antarctic bacterium, Planococcus versutus L10.15T, at low temperature through the production of an AHL lactonase. In this study, we cloned the AHL lactonase gene and characterized the purified novel enzyme. RESULTS: Rapid resolution liquid chromatography analysis indicated that purified AidP possesses high AHL-degrading activity on unsubstituted, and 3-oxo substituted homoserine lactones. Liquid chromatography-mass spectrometry analysis confirmed that AidP functions as an AHL lactonase that hydrolyzes the ester bond of the homoserine lactone ring of AHLs. Multiple sequence alignment analysis and phylogenetic analysis suggested that the aidP gene encodes a novel AHL lactonase enzyme. The amino acid composition analysis of aidP and the homologous genes suggested that it might be a cold-adapted enzyme, however, the optimum temperature is 28 °C, even though the thermal stability is low (reduced drastically above 32 °C). Branch-site analysis of several aidP genes of Planococcus sp. branch on the phylogenetic trees also showed evidence of episodic positive selection of the gene in cold environments. Furthermore, we demonstrated the effects of covalent and ionic bonding, showing that Zn2+ is important for activity of AidP in vivo. The pectinolytic inhibition assay confirmed that this enzyme attenuated the pathogenicity of the plant pathogen Pectobacterium carotovorum in Chinese cabbage. CONCLUSION: We demonstrated that AidP is effective in attenuating the pathogenicity of P. carotovorum, a plant pathogen that causes soft-rot disease. This anti-quorum sensing agent is an enzyme with low thermal stability that degrades the bacterial signalling molecules (AHLs) that are produced by many pathogens. Since the enzyme is most active below human body temperature (below 28 °C), and lose its activity drastically above 32 °C, the results of a pectinolytic inhibition assay using Chinese cabbage indicated the potential of this anti-quorum sensing agent to be safely applied in the field trials
Green technology of liquid biphasic flotation for enzyme recovery utilizing recycling surfactant and sorbitol
No full textLiquid biphasic flotation (LBF) system has been recognized as an efficient, green, economically sustainable and biocompatible technique for biomolecules separation and purification. The main drawbacks of the conventional process of biomolecules separation are expensive production cost, utilization of phase components that are inefficiently recycled and global pollution due to high chemical consumption and wastage. In this paper, a novel approach of LBF system for lipase recovery utilizing recycling phase components comprising surfactant and xylitol was investigated. The scope of this study focuses on pollution prevention as well as clean and environmentally friendly process for enzyme extraction via LBF. The green process proposed in this study uses phase-forming components that have recovery and recycling abilities for minimal use of chemicals for enzyme extraction. This novel method utilized Triton X-100 and xylitol for lipase extraction from Burkholderia cepacia. A few parameters were optimized to obtain high lipase separation efficiency and yield. Based on the ideal conditions of LBF, the average lipase separation efficiency and yield are 86.46 and 87.49%, correspondingly. Phase components recycling were proposed in order to reduce the chemicals consumption in LBF system. Upscaling of the recycling study exhibited consistent result with the laboratory scale. It was found that 97.20 and 98.67% of Triton X-100 and xylitol were recovered after five times of recycling and that a total of 75.87% of lipase separation efficiency was obtained. Recovery and recycling of phase components in the extraction process are established as the principal green chemistry method, which yields high separation efficiency and is economically feasible on an industrial scale
In vitro antibacterial activity of crude medicinal plant extracts against ampicillin+penicillin-resistant Staphylococcus aureus
No full textStaphylococcus aureus is the leading cause for foodborne diseases. Extensive use of antibiotics has led to emergence of antibiotic-resistant S. aureus. Hence, interest on natural plant-based alternative which limits the use of synthetic chemicals is growing. The present work evaluated the antibacterial capacity of garlic, aloe vera, galangal, pineapple peel, neem, papaya leaf, lemongrass, peppermint, nutmeg and clove separately extracted with hexane, ethanol and water to a final concentration of 10% w/v against ampicillin+penicillin-resistant isolates of S. aureus in vitro. Streptomycin was used as a drug control against the resistant isolates; BRS023, BRS068 and DRS072. According to the interpretive standards for inhibition zone diameter provided by the Clinical and Laboratory Standards Institute, isolates BRS068 and DRS072 were considered resistant (≤ 12 mm), and isolate BRS023 was considered intermediate (13-14 mm). Against these isolates, all crude plant extracts exhibited varying degrees of inhibition. However, a coherent trend was observed in the inhibition between resistant and intermediate isolates regardless of plants and solvents used. It was also found that extraction solvent types impacted the resulting antibacterial activity. In terms of positive inhibition, the solvents were ranked in the order of hexane (77%) > water (73%) > ethanol (57%). 10% hexane extract of galangal gave the overall highest inhibition zones (17.8 ± 1.4 mm) closely followed by 10% ethanol extract of nutmeg (16.3 ± 1.1 mm). Further phytochemical analyses of the antibacterial compounds from galangal and nutmeg, and their minimum inhibitory concentration (MIC) are needed. Potential applications of plant-based antibacterial compounds as natural, costeffective and less-toxic food preservatives against drug-resistant foodborne pathogens should be explored
Fatal spontaneous rupture of splenic artery aneurysm in third trimester pregnancy
No full textIntroduction: Unforeseen emergency in late pregnancy can be catastrophic and cause unexpected maternal and foetal demise. Moreover, lack of awareness and failure of prompt treatment raise mortality rate. Such fatalities warrant a forensic autopsy as it may raise redundant medico-legal concerns. Case Report: We report a case that revealed significant intra-abdominal haemorrhage at autopsy. The source of haemorrhage was at the spleen hilum and histology established rupture of splenic artery aneurysm. There was no associated obstetric cause found. Conclusion: Knowledge of spontaneous rupture of splenic artery aneurysm in late pregnancy is essential for monitoring maternal and foetal, morbidity and mortality. However, in the eventuality of death a comprehensive forensic autopsy is the only investigation to recognise such calamity and clear clinical confusion
Discriminative and Predictive Ability of Physical Performance Measures in Identifying Fall Risk among Older Adults
No full textFalls are a public health concern among older adults. There is a need to take significant measures such as screening for the risk of a fall as a means of prevention and management. A cross-sectional study was conducted to determine discriminative and predictive ability of physical performance measures in identifying the risk of fall among Malaysian community dwelling older adults. Three hundred twenty-five Malaysian community dwelling older adults aged 60 years and above (67.67+ 5.5 years) participated in this study. This study was a part of a larger longitudinal study ‘LRGS TUA’. Physiological Profile Assessment (PPA), a comprehensive tool for quantifying risk of fall was used as a standard measure of comparison to 6 Meter Gait Speed (GS), Timed Up and Go (TUG) and Walking While Talking (WWT) tests to establish discriminative and predictive ability. Participants recorded incidence of falls in a ‘falls diary’ over a span of six months. To determine the optimum cut off scores of the test identified to classify fall risk, receiver operator curves (ROC) were used and its sensitivity and specificity were calculated. A significant mean difference between fallers and non-fallers was demonstrated only with TUG test (p<0.05). TUG test cut off score in discriminating older adults at risk of fall was established at eight seconds, with a sensitivity and specificity of 83.95% and 32.4%, respectively, in this study. Eighty-four percent older adults who experienced a fall in our study were identified to be at risk of fall when screened using this TUG cut off score. Our study results suggested TUG test to be an optimal screening tool for risk of fall among community dwelling older adults
Kinematics and Timing of Brittle-Ductile Shearing of Mylonites along the Bok Bak Fault, Peninsular Malaysia
No full textStudy on the Bok Bak fault in Peninsular Malaysia reveals it to be a predominantly dextral brittle-ductile strike slip fault zone. This fault zone is characterized by gentle to sub-horizontal NE stretching lineation. The deformation occurred in a brittle-ductile domain. 40Ar/39Ar radiometric dating of biotite from the mylonite assigns an age of 136.1 ± 1.4 Ma. This age is the first reported radiometric dating of the Bok Bak fault, suggesting that the fault affected Sundaland prior to the collision between India and Asia, and therefore indicates an early faulting in the Malay Peninsula
A Comparison of the Variable Sampling Interval (VSI) and Variable Sample Size (VSS) Coefficient of Variation Charts
No full textAn efficient way to perform quality monitoring is important for a lot of industries, particularly in the manufacturing industry. Control charts are one of the important tools to monitor quality. Recently, control charts monitoring the coefficient of variation (CV) are proposed to monitor processes which do not have a constant mean and a standard deviation which changes with the mean. These processes
cannot be monitored by standard control charts which monitor the mean and/or standard deviation. The Variable Sampling Interval (VSI) and Variable Sample Size (VSS) CV charts are two recent charts proposed to improve the detection ability of CV charts. This paper compares the performance between these two charts in terms of the Average Time to Signal (ATS). The comparison shows that the VSS CV chart shows better performance when either a small sample size is taken or when a small shift in the CV needs to be detected.
Alternatively, the VSI CV chart outperforms the VSS CV chart. This paper will enable practitioners to know the conditions where the VSS CV chart outperforms the VSI CV chart, and vice versa. Hence, practitioners will be able to decide whether it is better to monitor their processes with a VSI or VSS scheme
Developing weighting system for refurbishment building assessment scheme in Malaysia through analytic hierarchy process (AHP) approach
No full textThe building industry has an undeniable impact on the natural environment. Evidence shows that existing buildings make a significant contribution to energy demand and CO2 emissions. Refurbishing existing buildings offers significant opportunities to reduce energy consumption and CO2 emissions. The Malaysian government has set a target to retrofit 100 government buildings in order to contribute to the country's commitment to reduce the CO2 emissions intensity of gross domestic product by 45% by 2030. However, there is no specific sustainability assessment scheme targeted at building refurbishment in Malaysia. Thus, this research aims to support the development of a refurbishment sustainability assessment scheme for Malaysia. The Analytic Hierarchy Process (AHP) method was adopted in order to rank assessment themes and identify the priorities of the study's participating stakeholders. The outcome is the Malaysian Refurbishment Assessment Scheme (MRAS), which includes a set of weightings and a classification system for the selected assessment themes and sub-themes. The methods and findings can be adapted for use by other practitioners to develop building assessment schemes in order to pursue the goals of sustainable development through refurbishment
Gender differences in mortality among ST elevation myocardial infarction patients in Malaysia from 2006 to 2013
No full textBACKGROUND: Coronary artery disease (CAD) is one of the leading causes of death in Malaysia. However, the prevalence of CAD in males is higher than in females and mortality rates are also different between the two genders. This suggest that risk factors associated with mortality between males and females are different, so we compared the clinical characteristics and outcome between male and female STEMI patients.
OBJECTIVES: To identify the risk factors associated with mortality for each gender and compare differences, if any, among ST-elevation myocardial infarction (STEMI) patients.
DESIGN: Retrospective analysis.
SETTINGS: Hospitals across Malaysia.
PATIENTS AND METHODS: We analyzed data on all STEMI patients in the National Cardiovascular Database-Acute coronary syndrome (NCVD-ACS) registry for the years 2006 to 2013 (8 years). We collected demographic and risk factor data (diabetes mellitus, hypertension, smoking status, dyslipidaemia and family history of CAD). Significant variables from the univariate analysis were further analysed by a multivariate logistic analysis to identify risk factors and compare by gender.
MAIN OUTCOME MEASURES: Differential risk factors for each gender.
RESULTS: For the 19484 patients included in the analysis, the mortality rate over the 8 years was significantly higher in females (15.4%) than males (7.5%) (P =65 years. The most prevalent risk factors for male patients were smoking (79.3%), followed by hypertension (54.9%) and diabetes mellitus (40.4%), while the most prevalent risk factors for female patients were hypertension (76.8%), followed by diabetes mellitus (60%) and dyslipidaemia (38.1%). The final model for male STEMI patients had seven significant variables: Killip class, age group, hypertension, renal disease, percutaneous coronary intervention and family history of CVD. For female STEMI patients, the significant variables were renal disease, smoking status, Killip class and age group.
CONCLUSION: Gender differences existed in the baseline characteristics, associated risk factors, clinical presentation and outcomes among STEMI patients. For STEMI females, the rate of mortality was twice that of males. Once they reach menopausal age, when there is less protection from the estrogen hormone and there are other risk factors, menopausal females are at increased risk for STEMI.
LIMITATION: Retrospective registry data with inter-hospital variation