19672 research outputs found
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Optimization of biodiesel production by microwave irradiation-assisted transesterification for waste cooking oil-Calophyllum inophyllum oil via response surface methodology
No full textIn this study, microwave irradiation-assisted alkaline-catalysed transesterification was used to produce W70CI30 biodiesel from a mixture of waste cooking oil and Calophyllum inophyllum oil. The methanol/oil ratio, catalyst concentration, stirring speed, and reaction time were optimized using response surface methodology based on the Box-Behnken experimental design in order to maximize the biodiesel yield. The quadratic response surface regression model was used to predict the biodiesel yield. It is found that the optimum methanol/oil ratio, catalyst concentration, stirring speed, and reaction time are 59.60 (v/v)%, 0.774 (w/w)%, 600 rpm, and 7.15 min, respectively, and the predicted biodiesel yield is 97.40%. Experiments were conducted using the optimum process parameters and the average biodiesel yield is 97.65%, which is in excellent agreement with the predicted value. The physicochemical properties of the W70CI30 biodiesel produced using the optimum process parameters were measured and it is found that the biodiesel has significantly higher oxidation stability (18.03 h) compared with the waste cooking oil biodiesel (4.61 h). In addition, the physicochemical properties and cold flow properties of the biodiesel fulfil the fuel specifications stipulated in the ASTM D6751 and EN 14214 standards. It can be concluded that microwave irradiation-assisted transesterification is effective to boost the biodiesel yield and produce biodiesel of superior quality. In addition, this method significantly reduces the reaction time of the transesterification process to 9.15 min and the process is energy-efficient. It is believed that the findings of this study will be beneficial for microwave irradiation-assisted biodiesel synthesis on the industrial scale
A study on the removal of propyl, butyl, and benzyl parabens via newly synthesised ionic liquid loaded magnetically confined polymeric mesoporous adsorbent
No full textThis study investigated the effectiveness of ionic liquids (ILs) loaded onto the surface of a polymeric adsorbent (βCD-TDI) grafted with modified magnetic nanoparticles (MNPs) via an analysis of water treatment, which resulted in high removal of selected endocrine-disrupting chemicals (parabens). The syntheses of MNPs, MNP-βCD-TDI, and IL-MNP-βCD-TDI were characterised and compared using Fourier transform infrared (FT-IR) spectroscopy, carbon-hydrogen-nitrogen (CHN) analysis, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results of SEM and TEM indicated that the pore size distribution exhibited mesoporous characteristics with a small surface area (BET analysis: 42.95 m 2 g -1 ). Furthermore, a preliminary sorption experiment demonstrated the ability of IL-MNP-βCD-TDI to enhance not only the sorption capacity, but also the removal of propyl paraben (PP), butyl paraben (BP), and benzyl paraben (ArP). The adsorption process appeared to be pH-dependent, and hence the optimum pH of 6 was selected for a subsequent batch adsorption study of all the studied parabens with an equilibrium time of 80 min. Next, in an attempt to investigate the interactions that occur between the adsorbent and the adsorbates, adsorption kinetics and isotherm studies were performed. All the studied parabens were found to best fit pseudo-second-order kinetics and the Freundlich isotherm with R 2 > 0.98 at room temperature (298 K). The interaction of the host-guest inclusion complex and the π-π interaction between βCD and a selected paraben compound (ArP) were identified by performing 1 H nuclear magnetic resonance (NMR), together with ultraviolet-visible (UV-vis) spectroscopic analysis. Finally, the adsorption efficiency of the developed material was practically tested on tap water, drain water, and industrial wastewater, which revealed a significant removal of parabens of up to 60-90% in comparison with a prior analysis
Copy number variation in VEGF gene as a biomarker of susceptibility to age-related macular degeneration
No full textBackground: Several studies in various populations have been conducted to determine candidate genes that could contribute to age-related macular degeneration (AMD) pathogenesis. Objective: The present study was undertaken to determine the association of high temperature requirement A-1 (HTRA1), vascular endothelial growth factor (VEGF) and very-low-density receptor (VLDR) genes with wet AMD subjects in Malaysia. Methods: A total of 125 subjects with wet AMD and 120 subjects without AMD from the Malaysian population were selected for this study. Genomic DNA was extracted and copy number variations (CNVs) were determined using quantitative real-time Polymerase Chain Reaction (qPCR) and comparison between the two groups was done. The demographic characteristics were also recorded. Statistical analysis was carried out using software where a level of P 0.05). Conclusion: Observations of an association between CNVs of VEGF gene and wet AMD have revealed that the CNVs of VEGF gene appears to be a possible contributor to wet AMD subjects in Malaysia
Benchmarking working conditions for health and safety in the frontline healthcare industry: Perspectives from Australia and Malaysia
No full textAim: To present benchmarks for working conditions in healthcare industries as an initial effort into international surveillance. Background: The healthcare industry is fundamental to sustaining the health of Australians, yet it is under immense pressure. Budgets are limited, demands are increasing as are workplace injuries and all of these factors compromise patient care. Urgent attention is needed to reduce strains on workers and costs in health care, however, little work has been done to benchmark psychosocial factors in healthcare working conditions in the Asia-Pacific. Intercultural comparisons are important to provide an evidence base for public policy. Design: A cross-sectional design was used (like other studies of prevalence), including a mixed-methods approach with qualitative interviews to better contextualize the results. Methods: Data on psychosocial factors and other work variables were collected from healthcare workers in three hospitals in Australia (N = 1,258) and Malaysia (N = 1,125). 2015 benchmarks were calculated for each variable and comparison was conducted via independent samples t tests. Healthcare samples were also compared with benchmarks for non-healthcare general working populations from their respective countries: Australia (N = 973) and Malaysia (N = 225). Findings: Our study benchmarks healthcare working conditions in Australia and Malaysia against the general working population, identifying trends that indicate the industry is in need of intervention strategies and job redesign initiatives that better support psychological health and safety. Conclusion: We move toward a better understanding of the precursors of psychosocial safety climate in a broader context, including similarities and differences between Australia and Malaysia in national culture, government occupational health and safety policies and top-level management practices
Kernel Bayesian ART and ARTMAP
No full textAdaptive Resonance Theory (ART) is one of the successful approaches to resolving “the plasticity–stability dilemma” in neural networks, and its supervised learning model called ARTMAP is a powerful tool for classification. Among several improvements, such as Fuzzy or Gaussian based models, the state of art model is Bayesian based one, while solving the drawbacks of others. However, it is known that the Bayesian approach for the high dimensional and a large number of data requires high computational cost, and the covariance matrix in likelihood becomes unstable. This paper introduces Kernel Bayesian ART (KBA) and ARTMAP (KBAM) by integrating Kernel Bayes’ Rule (KBR) and Correntropy Induced Metric (CIM) to Bayesian ART (BA) and ARTMAP (BAM), respectively, while maintaining the properties of BA and BAM. The kernel frameworks in KBA and KBAM are able to avoid the curse of dimensionality. In addition, the covariance-free Bayesian computation by KBR provides the efficient and stable computational capability to KBA and KBAM. Furthermore, Correntropy-based similarity measurement allows improving the noise reduction ability even in the high dimensional space. The simulation experiments show that KBA performs an outstanding self-organizing capability than BA, and KBAM provides the superior classification ability than BAM, respectively
Experimental Observation of Bright and Dark Solitons Mode-Locked with Zirconia-Based Erbium-Doped Fiber Laser
No full textWe demonstrate the generation of dark and bright solitons with our homemade zirconia-based erbium-doped fiber and graphene oxide (GO) saturable absorber in anomalous dispersion region. The GO is fabricated using an abridged Hummers method, which is combined with polyethylene oxide to produce a composite film. The film is sandwiched between two optical ferrules and embedded in the laser cavity to enhance its birefringence and nonlinearity. The self-starting bright soliton is easily generated at pump power of 78mW with the whole length cavity of 14.7 m. The laser produces the bright pulse train with repetition rate, pulse width, pulse energy and central wavelength being 13.9 MHz, 0.6 ps, 2.74 pJ and 1577.46 nm, respectively. Then, by adding the 10m of single mode fiber into the laser cavity, dark soliton pulse is produced. For the formation of dark pulse train, the measured repetition rate, pulse width, pulse energy and central wavelength are 8.3 MHz, 20 ns and 4.98 pJ and 1596.82 nm, respectively. Both pulses operate in the anomalous region
Adhesion and invasion attributes of Burkholderia pseudomallei are dependent on airway surface liquid and glucose concentrations in lung epithelial cells
No full textPhysiological constituents in airway surface liquids (ASL) appear to impact the adherence and invasion potentials of Burkholderia pseudomallei contributing to recrudescent melioidosis. Here, we investigated the factors present in ASL that is likely to influence bacterial adhesion and invasion leading to improved understanding of bacterial pathogenesis. Six B. pseudomallei clinical isolates from different origins were used to investigate the ability of the bacteria to adhere and invade A549 human lung epithelial cells using a system that mimics the physiological ASL with different pH, NaCl, KCl, CaCl 2 and glucose concentrations. These parameters resulted in markedly differential adherence and invasion abilities of B. pseudomallei to the lung epithelial cells. The concentration of 20 mM glucose dramatically increased adherence and invasion by increasing the rate of pili formation in depiliated bacteria. Glucose significantly increased adherence and invasion of B. pseudomallei to A549 cells, and presence of NaCl, KCl and CaCl 2 markedly ablated the effect despite the presence of glucose. Our data established a link between glucose, enhanced adhesion and invasion potentials of B. pseudomallei, hinting increased susceptibility of individuals with diabetes mellitus to clinical melioidosis
One Day the Emails Will End
No full textThe emails usually arrive around once a week. Sometimes they come in spurts. Sometimes weeks pass without one. They say that the wild pigs have been uprooting the banana grove. The cold weather seems to have affected the chickens' ability to lay eggs. The moon is full. It has been raining for days. The old cow at the ranch house has finally died.
My mother lives alone. She is 81. My father died in 2009 in a drowning accident. My younger brother lived with her for several years after that, but he has since moved to Wyoming. The house is quieter now. The television remote collects dust. The ants steadily march in from gaps in the floor. From time to time, the thrum of tropical showers breaks the silence.
She writes that the guys from Sears came again to repair the lawnmower blade. The avocados have been fruiting and falling; you should taste the smoothie I made. I have finished weeding on the shell ginger side; now moving to the row with the orchids. I got into a small accident by the library return bin and now there is a dent in the front bumper of the Jeep. The gas canister for the stove is almost empty.
Sometimes I answer the emails immediately, but usually I don't. I have meetings. I have errands. I have classes and bicycle rides and lunches and papers to write and mooting competitions to attend. The emails sit in the inbox, read but unanswered as they slowly drop down the screen to make way for new messages.
My mother has always preferred email to telephone calls or Skype. Before email, she loved to write letters in her scrawling cursive. From Hawai‘i they followed me, to college in Maine, then to Spain, New Hampshire, Ecuador, New York, transforming to email in the late 1990s to Arizona, Thailand, Myanmar, and now Malaysia. I responded in kind, which is perhaps where I started to love storytelling. The letters record our frustrations, empathy, adventures, happiness, sorrows, and love, but mostly they document the ordinary events that make up a life.
I receive another email. She had a doctor's appointment, ugh. In the waiting room she tries with all her might to calm herself. If she can just get her blood pressure down. If it is low, she will pray that the doctor will not test it again, but if it is high, she wants another chance. I have seen her practice in the dining room.
As Mom continues to age, I wonder whether I should move back home to be with her. She would insist that I not do so. She has always wanted the 5 of us siblings to experience life as an adventure. That means having the courage to travel, study, and explore the world—to live fully. Does this mean that we have to be separated by continents and oceans?
In the past few years, since Mom's house has become quieter, difficult questions come to my mind. When is the right time to move back with an aging parent? What sacrifices does it entail, and am I willing to make them? What regrets will I have if I wait too long? What regrets will I have if I return too soon? Can it ever be too soon?
On a visit home, I am driving at night with Mom. The conversation turns to death, which has been a topic of interest for me for the past several years. She tells me not to worry, that it is something that she has to go through on her own. I start to tear up. I say, perhaps out of emotion, “Sometimes I feel like there's nothing left to live for. I have done what I wanted, seen what I wanted to see.” She replies, “Yeah, I know what you mean.” We drive on in silence.
A child struggles with how to care for a rapidly deteriorating parent. A health crisis has hit. A mother or father has recently died. These are common themes in narratives about caring for older parents, but there is another stage that seems to be addressed less—the stage in which an aging parent is still healthy but surely will not be for much longer. This is the stage before crisis and death, of anticipated care. It is just as full of uncertainties and difficult decisions. The vagaries of health and death are always in the air. Should I wait for an emergency? Should I ask her whether I should return, and will her response matter? More important, are these questions even valid when it comes to caring for the person who has always cared for me and who sacrificed so much to nurture the life that I lead? If a baby does not one day care for a parent, who will?
Another email arrives. The chickens are laying again. The sun is out. She has mowed the lawn. The passion fruit and lemons are ripening.
I look in my email folder labeled “Mom and Dad.” As I scroll down, I read the subject lines: rats and annuities and fundraising and chocolate and family reunions. I find an email dated June 27, 2009, “Hi Mom and Dad, Just wanted to let you know that I am going to a meditation retreat for a couple weeks. I won't be checking emails or answering my phone for this time. Back online probably on July 12 or 13. Love, Stewart.” The reply comes from my dad, just 2 days later, on June 29, “Hi Stewart, Hope you are having a great time on your retreat and that it is in a beautiful place with wonderful people. Love Dad.”
When will be Mom's last email, what will it say and where will I be when she sends it
Effectiveness of T-shaped toothbrush in children: A pilot study
No full textDental caries and gingivitis are common oral health problems affecting schoolchildren worldwide. Effective tooth brushing in children is fundamental in preventing dental caries and gingivitis and maintaining good oral health. Children routinely present with unsatisfactory oral hygiene due to poor compliance and poor dexterity in tooth brushing. The purpose of the present study was to evaluate the effectiveness of a novel T-shaped toothbrush in plaque removal and gingival health among children and to obtain feedback regarding its use. Nineteen participants aged 8-10 years who fulfilled the criteria enrolled in this study. The children were taught the proper technique of using the new toothbrush and instructed to use it for a period of 2 weeks. The plaque scores and gingival scores were measured at baseline and after 2 weeks. They were asked to complete a questionnaire regarding the use of the toothbrush after 2 weeks. Statistical analysis was performed using t-test. There was a statistically significant (p < 0.05) reduction in mean (SD) plaque scores from baseline 1.96 (0.85) to 1.51 (0.75), after 2 weeks. Similarly, mean (SD) gingival scores reduced significantly from 0.20 (0.11) to 0.13 (0.08) over the two-week period. Overall, majority of participants (68% to 89%) gave positive feedback in all aspects regarding the use of T-shaped toothbrush, although 63.2% of them reported having difficulties to handle the T-shaped toothbrush initially. The T-shaped toothbrush can effectively improve oral hygiene in children with acceptable plaque removal and adequate gingival health in children
Prognostic factors for survival in pancreatic cancer patients from university Malaya medical centre, Malaysia
No full textObjectives: Pancreatic cancer is an aggressive silent killer with a median survival of a few months. It is the fourth leading cause of cancer death in the United States. The aim of this study was to evaluate the prognostic factors affecting the survival of patients with adenocarcinoma of the pancreas in Malaysia. Methods: This retrospective study examined 107 patients with adenocarcinoma of the pancreas from 2002 to 2012 at University Malaya Medical Centre. The factors evaluated were age, sex, race, smoking habits, performance status, the presence of jaundice, pre-treatment CA 19.9 serum level, the location of a primary tumour, tumour grade, tumour staging and intent of treatment. Results: The median survival for the overall study population was 7.0 months (95% CI 5.1-8.8 months) with 1, 3, and 5-year survival rates of 30.8%, 8.4% and 3.7% respectively. The survival was 16.1 months (95% CI 7.7-24.4 months) for stage 1, 15.5 months (95% CI 8.1-22.8 months) for stage 2, 8.4 months (95% CI 6.1-10.8 months) for stage 3, and 3.8 months (95% CI 2.9-4.7 months) for stage 4. In multivariate analysis, independent and unfavourable prognostic factors which retained significance were performance status, tumour stage and treatment intent. Conclusions: The biological characteristics are important as predictors of survival in patients with pancreatic cancer. Longer survival is possible if the disease is identified in its early stages with good performance status. Further development and evaluation of novel screening strategies need to be established to improve early detection of this disease