We demonstrate a multi-wavelength light source using a semiconductor optical amplifier (SOA) in conjunction with an array waveguide grating (AWG). The experimental results showed more than 20 channels with a wavelength separation of 0.8 nm and an optical signal-to-noise ratio of more than 10 dB under room temperature. The channels operated at the wavelength region from 1530.4 nm to 1548.6 nm, which corresponded to AWG filtering wavelengths with SOA drive current of 350 mA. The proposed light source had the advantages of a simple and compact structure, multi-wavelength operation and the system could be upgraded to generate more wavelengths.
In this present study, enzymatic esterification synthesis of fructose laurate was performed in organic media using lipase from Candida antarctica immobilized on acrylic resin. Screening phase of esterification reaction was done using two commonly used commercial immobilized lipases, in three different solvents, molecular sieve loadings, and reaction time to observe their effect on the yield of fructose laurate. The highest yield was obtained by using ethanol as the solvent, 0.02 g lipase loading, 0.10 g molecular sieves loading, and 24 hr of reaction time. By using response surface methodology (RSM) with central composite design (CCD), it was found that the optimum operational conditions were 40°C, 0.13 g lipase loadings, 200 rpm agitation rate, and without molecular sieve needed for the system. The optimized esterification conditions could give the yield of fructose laurate about 93.21 ± 0.13% with 92.91% confidence level.
An efficient erbium/ytterbium co-doped fibre amplifier was demonstrated by using a dual-stage partial doublepass structure with a band-pass filter (BPF). The amplifier achieved the maximum small signal gain of 56 dB and the corresponding noise figure of 4.66 dB at 1536 nm with an input signal power and total pump power of –50 dBm and 140 mW, respectively. Compared with a conventional single-stage amplifier, the maximum gain enhancement of 16.99 dB was obtained at 1544 nm with the corresponding noise figure was improved by 2 dB. The proposed amplifier structure only used a single pump source with a partial double pass scheme to provide a high gain and dual-stage structure to provide the low noise figure.
In recent years, the search for natural, safe and effective therapies for the management of obesity has become important. The present study investigated the potential of brown seaweeds Sargassum oligocystum and Padina australis from Malaysian waters as natural alternatives for the management of obesity. Both seaweeds were macerated using acetone at room temperature for ten hours. The S. oligocystum extracts (SE) and P. australis extracts (PE) were then applied to 3T3-L1 cells during the differentiation stage and during the mature stage of the adipocyte life cycle to assess the effects of extracts on adipogenesis and adipolysis. Application of SE at 12.5 and 50 µg/ml to the cells decreased adipogenesis by 71.7%, and 84.8%, respectively, while cells treated with 12.5 and 50 µg/ml PE showed 85.7%, and 89.0% adipogenesis respectively, compared to control. Application of SE and PE to mature lipid cells stimulated adipolysis and the release of glycerol into the culture media. Application of SE at 12.5 and 50 µg µg/ ml in the cell media induced glycerol release by up to 88.6 and 93.0%, respectively, while PE increased glycerol release up to 92.9 and 95.6% respectively, compared to isoproterenol. This study demonstrates the potential of whole brown seaweed extracts from S. oligocystum and P. australis collected from Malaysian waters as natural anti- obesity agents. Incorporation of the brown seaweed into the diet as a functional food will be useful for prevention and treatment of obesity.
Gastrodin elata blume (Tianma in Chinese, Chunma in Korean) is a perennial parasitic herbaceous plant native to Korea, Japan and China (Chae et al., 2008). The plant has recently received very good attention, especially in Korea, due to its excellent health-promoting properties. This plant is reported to have excellent antioxidant, anticancer and anti-inflammatory properties. This paper briefly reviews some characteristics and functional properties of Chunma.
PURPOSE: To assess the relationship between glycaemic control and quality of life (QoL) among a sample of Malaysians with type 2 diabetes mellitus.
METHODS: This study is a cross-sectional hospital-based study involving 256 patients from three major ethnic groups in Malaysia. Data about QoL were collected with the 18-item Audit of Diabetes Dependent QoL questionnaire. Other data about putative predictors of QoL including personal characteristics and disease-related factors were also collected. Hierarchical multiple linear regression was used to determine factors associated with QoL and to control for confounding variables.
RESULTS: The mean age of participants was 56.79 years. Participants were mostly women, employed and married and had attained secondary education. More than a third of the patients had a disease duration of more than 10 years, and about two-thirds had HbA1c ≥ 6.5 %. Those with desired glycaemic control had poorer QoL than those with less than desired glycaemic control moderated by the use of insulin. Hierarchical multiple linear regression showed that desired glycaemic control (HbA1c), diabetes worry, use of insulin, more than 10 years' duration of diabetes, neuropathy and retinopathy were associated with poor QoL, whereas being satisfied with waiting time for consultation was associated with better QoL.
CONCLUSIONS: The results of this study show that diabetes was associated with negative impact on quality of life. The use of insulin to achieve desired glycaemic control was particularly associated with negative impact on QoL.
Recently, assistive explanations for difficulties in the health check area have been made viable thanks in considerable portion to technologies like deep learning and machine learning. Using auditory analysis and medical imaging, they also increase the predictive accuracy for prompt and early disease detection. Medical professionals are thankful for such technological support since it helps them manage further patients because of the shortage of skilled human resources. In addition to serious illnesses like lung cancer and respiratory diseases, the plurality of breathing difficulties is gradually rising and endangering society. Because early prediction and immediate treatment are crucial for respiratory disorders, chest X-rays and respiratory sound audio are proving to be quite helpful together. Compared to related review studies on lung disease classification/detection using deep learning algorithms, only two review studies based on signal analysis for lung disease diagnosis have been conducted in 2011 and 2018. This work provides a review of lung disease recognition with acoustic signal analysis with deep learning networks. We anticipate that physicians and researchers working with sound-signal-based machine learning will find this material beneficial.
We analyzed the characteristics of patients presenting with acute pancreatitis to our unit. A total of 71 patients were admitted to the Surgical Department at University Kebangsaan Malaysia (UKM) over a period of seven years, between January 1990 to December 1996 with acute pancreatitis. There was a fourfold increase in incidence of acute pancreatitis in our hospital from January 1990 to December 1996. The commonest identifiable aetiology was gallstones followed by alcohol. There were two deaths. We conclude that acute pancreatitis is increasingly being diagnosed in our local population. This may be due to either greater awareness or changes in lifestyle of the population.
Intrahepatic stones remain a major source of morbidity and mortality. With improving techniques in hepatobiliary surgery, the management and the outcome of intrahepatic calculi is reviewed. Forty-nine cases referred from all over Malaysia between January 1993 to June 1996 were analyzed retrospectively. There were thirty-two females and seventeen males. The median age was 46 years. Biliary diseases encountered in association with intrahepatic calculi included benign strictures (n = 14), ascariasis (n = 3), cholangiocarcinoma (n = 1), Caroli's disease (n = 1), and thalassaemia, (n = 1), fifty-six percent of stones were located in both the intrahepatic ducts while 34% were found in the left intrahepatic duct. Thirty-one patients underwent common bile duct exploration either alone or in combination with liver resection or bilioenteric anastomosis. Despite the various combinations of surgical and non-surgical intervention 28 (57.1%) patients had residual stones. Despite the availability of newer techniques in hepatobiliary surgery, residual stones were common, resulting in higher treatment costs.
This paper demonstrates an erbium/ytterbium co-doped fi bre amplifi er (EYDFA) which used a pumping wavelength of 1058 nm, whereby the amplifi cation was assisted by the energy transfer between Yb and Er ions. The energy transfer increased the erbium doping concentration limit that was imposed by concentration quenching in erbium-doped fi bre. The optimum length was obtained at 4m~6m for erbium/ytterbium co-doped fi bre with Er ion concentration of 1000 p.p.m. This enabled the development of a compact amplifi er with a shorter gain medium compared to erbium-doped fi bre amplifi ers which use a gain medium of up to 15 m. A 1058 nm pumping wave-length was used for the EYDFA, as 1480 nm pumping resulted in severely degraded gain and noise fi gures because the energy transfer could not be achieved. The use of the optical isolator improved the small signal gain and noise fi gure by about 4.8 dB and 1.6 dB, respectively. Without the isolator, gain saturation and a noise fi gure penalty were observed due to the oscillating laser which was created at around 1534 nm by spurious refl ection. This showed that the usage of optical isolators was an important aspect to consider when designing an EYDFA.
A distributed feedback fibre laser made of highly Er-Yb co-doped phosphate glass fibre was demonstrated experimentally. The 45 mm long fibre laser device operated at 1540 nm with more than 50 dB side mode suppression ratio. However, the output power was still relatively lower due to un-optimized grating structure and thermal management.
Introduction: The incidence of dengue has risen dramatically high over the last few decades worldwide. Some three billion people are at risk of getting infected with dengue. In Malaysia the total number of dengue cases has been rising annually. In Perak, the number of cases for dengue fever and hemorrhagic dengue fever increased from 421 cases per 100000 population in 2012 to 1024 cases per 100000 in 2013 accounting for an increase of 143.2%. This study aimed to assess the knowledge, practice of preventive measures and effectiveness of health promotion related to dengue among residents of a village in Ipoh.
Methodology: This cross sectional study was conducted in 2015. Simple random sampling was applied to choose the samples.
Results and discussion: Out of a total of 408 respondents, 61.3% and 74% obtained good scores in knowledge and preventive practice measures respectively. The highest misconceptions occurred on behavior aspects of the Aedes mosquitoes (46.6%) and availability of vaccinations for dengue (40.7%) while 65% of respondents allow fogging activities to be conducted at 2pm (noon). Significant associations were shown between types of occupation and knowledge (p=0.017), level of education and practice (p=0.022), previous exposure among family members and practice (p=0.016), and between knowledge and practice (p=0.011). In conclusion, despite having good knowledge about dengue and potential breeding sites of the Aedes mosquito, the number of dengue cases rising could be due to a quarter of population having poor preventive practices.
This study evaluated the potential of bioflocculant production from Aspergillus niger using palm oil mill effluent (POME) as carbon source. The bioflocculant named PM-5 produced by A. niger showed a good flocculating capability and flocculating rate of 76.8% to kaolin suspension could be achieved at 60 h of culture time. Glutamic acid was the most favorable nitrogen source for A. niger in bioflocculant production at pH 6 and temperature 35 °C. The chemical composition of purified PM-5 was mainly carbohydrate and protein with 66.8% and 31.4%, respectively. Results showed the novel bioflocculant (PM-5) had high potential to treat river water from colloids and 63% of turbidity removal with the present of Ca(2+) ion.
The production and characterization of a bioflocculant, IH-7, by Aspergillus flavus was investigated. About 0.4 g of purified bioflocculant with an average molecular weight of 2.574 × 10(4)Da could be obtained from 1L of fermentation medium. The bioflocculant mainly consisted of protein (28.5%) and sugar (69.7%), including 40% of neutral sugar, 2.48% of uronic acid and 1.8% amino sugar. The neutral sugar components are sucrose, lactose, glucose, xylose, galactose, mannose and fructose at a molar ratio of 2.4:4.4:4.1:5.8:9.9:0.8:3.1. Fourier-transform infrared spectroscopy analysis revealed that purified IH-7 contained hydroxyl, amide, carboxyl and methoxyl groups. The elemental analysis of purified IH-7 showed that the weight fractions of the elements C, H, O, N and S were 29.9%, 4.8%, 34.7%, 3.3%, and 2.0%, respectively. IH-7 had good flocculating rate in kaolin suspension without cation addition and stable over wide range of pH and temperature.
DC distribution of PV systems has spread back especially in the residential sector as a variety of electronic appliances became locally available in the market. The compatibility of household appliances with the best voltage-level in a DC environment is the field that still in the research phase and has not yet made a practically extensive appearance. This paper mainly discusses this issue by providing a review of the concerning research efforts, identifying the gaps in the existing knowledge. The work explains the electrical diagrams of the recently produced appliances, classifying them to get an understanding of how each one consumes energy. It includes exploiting the recent dependence of the commercial appliances on power electronics to improve the efficiency of the existing DC distribution systems by extrapolating new architectures. The proposed topology has a DC distribution environment with two levels of voltage for all appliances. Appliances performances have been evaluated by calculating the energy transfer efficiency. The outcomes of this work can help in designing more efficient DC power distribution networks with minimal energy converters and establishing standardizations for DC microgrids.
At present, a limited amount of information exists on the association between cognitive reserve and cognitive impairment in stroke populations. To determine predictors of cognitive reserve among stroke patients, 80 stroke patients attending the neurological and rehabilitation clinic in two different Malaysian general hospitals participated in this study. The Malay Cognitive Reserve Index questionnaire (CRIq-M), Depression Anxiety and Stress Scales-Short Form (DASS-21), WHO Quality of Life assessment BREF-21 (WHO-QOL BREF-21), Montreal Cognitive Assessment (MoCA), and modified Rankin Scale (mRS) were used as instruments in this study. The study found that cognitive reserve (CRIq-M) is positively correlated with cognitive function (MoCA), r = 0.529, p
A single-wavelength Brillouin fiber laser (BFL) is demonstrated at the extended L-band region using bismuth-based erbium-doped fiber (Bi-EDF) for the first time to the best of our knowledge. A 2.15-m-long Bi-EDF is used to provide both nonlinear and linear gains to generate a stimulated Brillouin scattering (SBS) and to amplify the generated SBS, respectively. The BFL operates at 1613.93 nm, which is upshifted by 0.09 nm from the Brillouin pump with a peak power of 2 dBm and a side-mode suppression ratio of more than 22 dB. The generated BFL has a narrow linewidth and many potential applications, such as in optical communication and sensors.
A multi-wavelength laser comb is demonstrated using a nonlinear effect in a backward pumped Bismuth-based Erbium-doped fiber (Bi-EDF) for the first time. It uses a ring cavity resonator scheme containing a 215 cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10 dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.
Larviciding is an effective control method in managing mosquito-borne diseases. However, most of the current larvicide formulations have raised environmental concerns due to the presence of non-biodegradable inert or carrier materials. Therefore, the utilisation of biodegradable natural cellulosic fibres has created much attention. This study aims to evaluate the application of biodegradable kenaf cellulose nanofibre (KCNF) in larvicide formulation where the larvicide, namely temephos, is impregnated onto the fibre matrix (KCNF+T). The bioefficacy of the formulation was evaluated against Aedes aegypti ( A. aegypti) mosquito larvae. The presence of the temephos on the KCNF was evaluated through micro- morphological analysis using a field emission scanning electron microscope (FESEM) and a transmission electron microscope (TEM), while the quantity of temephos impregnated, released, and retained on the fibres upon dispersion in water were determined using high performance liquid chromatography (HPLC). It was observed that 97% of the temephos (0.1 mg) were impregnated on the KCNF. Upon dispersion in water, 53% of the temephos were released from the KCNF+T and the retention of temephos on the KCNF+T gradually decreased to 30%, 17%, and 7% on the first, third, and fifth month, respectively. Exposure of the A. aegypti larvae to the KCNF+T at concentrations ranging between 0.006 to 0.01 mg/L was effective in killing A. aegypti larvae at 17-25 folds as compared to using the temephos without KCNF. Microscopic examination revealed the accumulation of the KCNF on the larval appendages. In conclusion, this study demonstrated that the utilisation of KCNF in pesticide formulation is an effective way of delivering the temephos to control A. aegypti mosquito larva.