The effects of six pretreatments of five agricultural wastes (corn cob, pineapple waste, bagasse, rice straw and water
hyacinth) on the chemical composition and total reducing sugar yield were investigated. Six pretreatments were: 1% NaOH
with ultrasound for 60 min; 1% NaOH with ultrasound 100% duty; 2% NaOH with ultrasound for 60 min; 2% NaOH
with ultrasound 100% duty cycle; 1% NaOH by standing in the oven at 60°C for 90 min; and 2% NaOH by standing
in the oven at 60°C for 90 min. Among them, the highest cellulose content of 55.15% was obtained from bagasse by
pretreating with 1% NaOH with ultrasound 100% duty cycle. It subsequently yielded the highest total reducing sugar of
36.21% (36.21 g reducing sugar/100 g substrate). The lignin content of all samples significantly decreased, but ultrasonic
pretreatment increased the cellulose content. However, the best pretreatment method for each sample was different. Based
on SEM analysis, the morphologies of all samples were changed after pretreatment. In addition, the increase of enzyme
loading from 250 to 550 CMC U/g biomass led to more than 20% increase in the total reducing sugar. It was found that
the higher enzyme loading (700 CMC U/g dried biomass) did not improve the total reducing sugar for all samples.
Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
The study to determine the concentrations of dissolved heavy metals in the Sungai Semenyih and to use the environmetric
methods to evaluate the influence of different pollution sources on heavy metals concentrations was carried out. Cluster
analysis (CA) classified 8 sampling stations into two clusters based on the similarity of sampling stations characteristics,
cluster 1 included stations 1, 2, 3 and 4 (low pollution area), whereas cluster 2 comprised of stations 5, 6, 7 and 8
(high pollution area). Principal component analysis (PCA) of the two datasets yield two factors for low pollution area
and three factors for the high pollution area at Eigenvalues >1, representing 92.544% and 100% of the total variance
in each heavy metals data sets and allowed to gather selected heavy metals based on the anthropogenic and lithologic
sources of contamination.
Pemprosesan logam separa pepejal yang juga dikenali sebagai pembentukan-tikso merupakan suatu kaedah pemprosesan
yang secara relatifnya adalah baharu jika dibandingkan dengan kaedah pemprosesan biasa seperti penuangan dan
penempaan. Sebelum pembentukan-tikso dapat dilakukan, aloi berkenaan perlu melalui langkah awal persediaan iaitu
dengan mengubah mikrostruktur asal berbentuk dendritik kepada bentuk hampir sfera. Ini diikuti dengan pemanasan
semula ke julat suhu separa pejal (iaitu sekitar 30-50% cecair) dan seterusnya proses ubah bentuk ke dalam acuan
menggunakan mesin penekanan hidraulik. Antara kaedah utama yang biasa digunakan bagi penyediaan bahan aloi
ini adalah tuangan cerun penyejukan, pengadukan mekanik dan kaedah terma langsung. Kajian ini memberi tumpuan
kepada evolusi mikrostruktur aloi aluminium A333 (Al-7.5Si-3.1Cu) daripada bentuk dendritik kepada hampir sfera
sebagai persediaan untuk diproses melalui pembentukan-tikso kelak. Kaedah tuangan cerun penyejukan digunakan
dalam kajian ini kerana kaedah ini diketahui berkesan tapi mudah digunakan. Nilai saiz ira dan faktor bentuk dianalisis
berdasarkan kepada suhu tuangan dan panjang cerun penyejukan berbeza yang digunakan. Di samping itu, kaedah
kalometri pengimbas perbezaan juga diguna pakai dalam mengenal pasti suhu sempadan pepejal dan sempadan cecair
aloi ini. Saiz ira fasa pepejal α-Al paling kecil dan nilai faktor bentuk terbaik yang diperoleh dalam kajian ini berlaku
pada suhu tuangan 620°C dan panjang cerun 300 mm, iaitu masing-masing pada 15.3 µm dan 0.54.
In this paper, the fully implicit 2-point block backward differentiation formula and diagonally implicit 2-point block
backward differentiation formula were developed under the interpretation of generalized differentiability concept for
solving first order fuzzy differential equations. Some fuzzy initial value problems were tested in order to demonstrate the
performance of the developed methods. The approximated solutions for both methods were in good agreement with the
exact solutions. The numerical results showed that the diagonally implicit method outperforms the fully implicit method
in term of accuracy.
In this paper, the problem of free convection boundary layer flow on a horizontal circular cylinder in a nanofluid with viscous dissipation and constant wall temperature is investigated. The transformed boundary layer equations are solved numerically using finite difference scheme namely the Keller-box method. Numerical solutions were obtained for the reduced skin friction coefficient, Nusselt number and Sherwood number as well as the velocity and temperature profiles.The features of the flow and heat transfer characteristics for various values of the Brownian motion parameter, thermophoresis parameter, Lewis number and Eckert number were analyzed and discussed.
A new numerical method was proposed in this paper to address the nonlinear quadratic optimal control problems, with state and control inequality constraints. This method used the quasilinearization technique and Haar wavelet operational matrix to convert the nonlinear optimal control problem into a sequence of quadratic programming problems. The inequality constraints for trajectory variables were transformed into quadratic programming constraints using the Haar wavelet collocation method. The proposed method was applied to optimize the control of the multi-item inventory model with linear demand rates. By enhancing the resolution of the Haar wavelet, we can improve the accuracy of the states, controls and cost. Simulation results were also compared with other researchers' work.
A well-known planting medium in soilless culture is a coconut based material famously known in Malaysia as cocopeat.
It is a viable ecologically friendly peat soil substitute for containerized crop production. The multipurpose growing media
had received much interest particularly in commercial applications. This study focused on the physical and hydraulic
characteristics of cocopeat perlite mixture as a growing media in containerized plant production. Perlite was added to
cocopeat at a ratio of 3 cocopeat: 1 perlite. Bulk density, particle density, porosity, particle size distribution, water holding
capacity, wettability and hydraulic conductivity of the media were evaluated. About 82.93% of the total particles were
in the range between 0.425 and 4 mm in diameter at a bulk density of 0.09 g/cm3
. Total porosity (79%) and wettability
improved with the incorporation of perlite to cocopeat. This study showed that water holding capacity was very high at
912.54% whereas the saturated hydraulic conductivity was low at 0.1 cm/s. The results showed that adding perlite to
cocopeat had improved the physical and hydraulic characteristics of the media.
Higher level of education is associated with better cognitive performance and lower risk of developing dementia. However, the effect of education on cognitive performance varies across different cognitive domains and in different populations. The aim of this study was to determine the relationship between education and performance of different cognitive domains among healthy Malay adults. A total of 53 individuals aged 29 to 77 years participated in a battery of neurophysiological tests consisting of Mini-Mental State Examination, Montreal Cognitive Assessment, digit span, visual reproduction and digit symbol speed test (DSST). Blood test was performed for each participant to obtain their biochemical profile. Educational level was divided into level 1 (PMR), level 2 (SPM), level 3 (STPM), level 4 (Diploma) and level 5 (Degree). Simple linear regression indicated that years of education was positively associated with scores of delayed visual reproduction (b=1.348, p=0.002) and DSST (b=3.257, p=0.012). However, scores of all the tests were not significantly different among different levels of education after controlling for age, gender and blood test profile by ANCOVA. Multiple linear regression analysis showed that MMSE score was associated with red cell distribution width (b=-0.628, p=0.005), age (b=-0.119, p<0.001) and there was interaction between high density lipoprotein (HDL) with age (b=0.047, p<001). MoCA score was associated with age (b=-0.121, p<0.001), gender (male compared to female, b=1.870, p=0.020) and HDL (b=1.681, p=0.047). Age was associated with backward digit span (b=-0098, p<0.001) and immediate visual reproduction (b=-0.348, p<0.001), resp. Delayed visual reproduction was associated with age (b=-0.323, p<0.001) and potassium level (b=-4.471, p=0.016). DSST was associated with age (b=-0.911, p<0.001) and alanine aminotransferase (b=-0.754, p=0.002). The lack of association between educational level and cognitive performance after adjusting for confounders in this study maybe due to multiple factors influencing cognitive performance and further studies with a larger sample size are needed to further identify the factors involved.
Keywords: Cognitive performance; education; healthy Malay adults
ABSTRAK
Tahap pendidikan yang tinggi telah dikaitkan dengan prestasi kognitif yang lebih baik dan risiko perkembangan dementia yang lebih rendah. Namun, kesan pendidikan terhadap prestasi kognitif berbeza antara domain kognitif dan populasi yang berlainan. Kajian ini bertujuan untuk menentukan hubungan antara pendidikan dengan prestasi pada domain kognitif yang berlainan pada individu dewasa Melayu yang sihat. Seramai 53 individu yang berumur antara 29 hingga 77 tahun telah menyertai ujian neuropsikologi yang terdiri daripada Pemeriksaan Keadaan Mental Mini, Penilaian Kognitif Montreal, digit span, penghasilan semula visual dan ujian kelajuan simbol digit (DSST). Tahap pendidikan dibahagikan kepada tahap 1 (PMR), tahap 2 (SPM), tahap 3 (STPM), tahap 4 (Diploma) dan tahap 5 (Ijazah Sarjana Muda). Regresi linear mudah menunjukkan bahawa tahap pendidikan berhubung kait secara positif dengan penghasilan semula visual tertunda (b=1.348, p=0.002) dan DSST (b=3.257, p=0.012). Namun, semua skor ujian menjadi tidak berbeza antara tahap pendidikan yang berbeza selepas mengambil kira kesan konpengasas dengan menggunakan ANCOVA. Regresi linear berganda menunjukkan bahawa skor MMSE berhubung kait dengan lebar taburan sel merah (b=-0.628, p=0.005), umur (b=-0.119, p<0.001) dan interaksi antara lipoprotein ketumpatan tinggi (HDL) dan umur (b=0.047, p<001). MoCA didapati berhubung kait dengan umur (b=-0.121, p<0.001), jantina (lelaki berbanding perempuan, b=1.870, p=0.020) dan HDL (b=1.681, p=0.047). Umur juga berhubung kait dengan digit span ke belakang (b=-0098, P<0.001) dan penghasilan semula visual segera (b=-0.348, p<0.001). Penghasilan semula visual tertunda berhubung kait dengan umur (b=-0.323, p<0.001) dan tahap kalium (b=-4.471, p=0.016). DSST berhubung kait dengan umur (b=-0.911, p<0.001) dan alanin aminotransferase (b=-0.754, p=0.002). Hubungan antara tahap pendidikan dan prestasi kognitif tidak dikesan selepas mengambil kira kesan konpengasas yang mencadangkan bahawa prestasi kognitif mungkin dipengaruhi oleh pelbagai faktor dan kajian lanjut dengan bilangan sampel yang lebih besar diperlukan untuk mengenal pasti faktor ini.
Older adults quite often had an inadequate diet leading to micronutrient deficiencies and impaired immune response with subsequent development of degenerative diseases. This study aimed to determine the adequacy of energy and nutrient intake and its distribution among three aging groups i.e. successful aging (SA), usual aging (UA) and mild cognitive impairment (MCI). This is a cross-sectional study involving a large sample size (n = 2322) of older adults recruited through multistage random sampling from four states of Malaysia. An interview was conducted to measure dietary intake, neurocognitive status and functional status by using the Diet History Questionnaire (DHQ), Mini-Mental State Examination (MMSE), Rey Auditory Learning Test (RAVLT), Geriatric Depression Scale (GDS), Instrumental Activity of Daily Living (IADL) and Quality of Life Questionnaire. For comparison of dietary intake, a sub-sample of 173 respondents from each aging groups were matched and selected using a comparative cross-sectional approach. Women in SA group had the highest mean intake of vitamin A, calcium (p <0.05), vitamin C, riboflavin and iron (p<0.001). The same aging group also achieved the highest RNI percentage for the same nutrients. More than 80% of respondents for all aging groups did not met the recommended nutrient intake (RNI) for vitamin E, thiamin, niacin, folate, calcium and zinc. In women, MCI respondents were more likely to have an inadequate intake of vitamin A, C, riboflavin and iron followed by UA and SA. Inadequate vitamin E, niacin, folate and calcium were prevalent among all gender and aging groups. There is a need to further distinguish specific dietary patterns associated with these three aging groups to promote optimal nutrient intake for cognitive health.
ABSTRACT
There is an increasing trend of fruit juice consumption due to increasing reported health benefits of antioxidant content present in fruit juices. The aim of this study was to compare the total phenolic contents (TPC) and antioxidant activities of fresh fruit juices, commercial 100% fruit juices and fruit drinks. Seven types of freshly blended fruit juices and their commercial counterparts were selected. Folin-Ciocalteu method was used to determine the total phenolic content, whilst ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were performed to evaluate the antioxidant activities of fruit juices. The TPC contents of fresh fruit juices, commercial 100% fruit juices and fruit drinks were at the ranges of 13.38-80.40, 21.65-130.39 and 3.32-45.10 mg GAE/100 mL, respectively. Both fresh guava juice and commercial guava drinks have exhibited the highest antioxidant activities in DPPH assay (205.71-770.12 μmol TE/100 mL) and FRAP assay (320.80-843.13 μmol TE/100 mL). Pomegranate juices demonstrated the highest antioxidant activities among commercial 100% fruit juices with DPPH and FRAP values of 2705.01 and 2953.85 μmol TE/100 mL, respectively. Fruits drinks group had the lowest TPC and antioxidant activities for all types of fruits. TPC was significantly correlated (p<0.05) to FRAP (r=0.954) and DPPH (r=0.908) assays. In conclusion, the TPC and antioxidant activities of commercial 100% fruit juices and fresh juices were comparable as no significantly difference (p>0.05) was found between these two groups. Commercial fruit drinks in this study were not good source of antioxidants. These findings provide some useful information especially for ageing population in choosing healthy fruit juice or drinks for their health maintenance purposes.
Soy-based products are one of famous raw ingredients used in the preparation of Asian cuisines. These soy-based products are good source of isoflavones. This study was carried out to observe the effects of different cooking methods on isoflavone content in soy-based products. A total of eight Malaysian dishes prepared using soy-based products with different cooking methods was selected as samples for this study. Daidzein and genestein contents in raw and cooked soy-based products were both quantified using high performance liquid chromatography (HPLC). The results showed that dishes containing tempe as ingredients had significantly higher (p<0.05) amount of isoflavone content, in both raw and cooked forms, as compared to those prepared from other types of soy-based products when based on dry and wet. In conclusion, the isoflavone content was significantly reduced (p<0.05) in some cooked soy-based products (tempe (TSS and ML), fu jook (ML) and firm tofu (FTC)) based on dry weight as compared with the raw ones. However, the correlations between isoflavone content with cooking methods, durations and temperatures were not significant (p>0.05) in this study.
The goal of this study was to examine the reliability and validity of the Bahasa Malaysia version of the Montreal cognitive assessment (MoCA-BM) and to determine its optimal cut-off score among older adults with mild cognitive impairment (MCI), after adjustments for age, gender, levels of education, physical functioning and depressive symptoms. A total of 2237 community dwelling older adults aged 60 years and above were randomly selected for the study, excluding those with MMSE score below 14. Instruments administered were the MoCA-BM, the Malay Mini-Mental State Examination (MMMSE), the Rey Auditory Verbal Learning Test (RAVLT), the Digit Span and the Digit Symbol subtests of the Wechsler Adult Intelligence Scale (WAIS), activities of daily living (ADL) and the Geriatric Depression Scale (GDS). MCI were determined using the Petersen’s 2014 criteria as the gold standard. SPSS version 22 was used for reliability and validity analysis and optimal cut-off score detection. Cronbach’s α of the MoCA-BM was 0.691 and concurrent validity was high between MoCA-BM and MMMSE scores (r=0.741). Optimal cut-off point for MoCA-BM to detect MCI among older adults in Malaysia was 17/18, with sensitivity of 68.2% and specificity of 61.3%. Using this cut-off, 38.9% of participants were detected to be at risk of MCI. In conclusion, MoCA-BM is a reliable and valid screening instrument for MCI among Malaysian elderly community. The newly derived optimal cut-off for MCI is much lower than the original MoCA with modest ability to discriminate between normal and MCI older adults in the community.
The purpose of this study was to examine the impact of aging on economic growth. The study used dynamic growth model and employed Autoregressive Distributed Lag (ARDL) approach for the period of 1980 to 2011. Three proxies for aging are used namely fertility rate, life expectancy and old dependency ratio. However, only fertility rate is detected to have a long run cointegration. The major finding of this study showed that a reduction of fertility rate lead to higher economic growth. This implied that even though Malaysia will face aging society by 2020, the economic growth is still stable and can increase by investing more on human capital.
The improvement of health care support has greatly extended the average life expectancy over the last 50 years, which
has increased the rate of cognitive decline consequently. The avoidance of risk factors such as toxins, stress and somatic
diseases can be protective against the reduction of cognitive function in the elderly. This study aimed to determine the
effects of socio-demographic factors, constipation and renal failure on cognitive status among 2322 samples who were
the non-institutionalized Malaysian elderly. The multiple logistic regression analysis was applied to estimate the risk of
such factors on cognitive decline in subjects. Approximately, 77.54% of samples experienced cognitive impairment. The
results showed that advanced age (odds ratio (OR) = 1.03), Malay ethnic (OR = 2.15), constipation (OR = 3.31) and renal
failure (OR= 4.42), significantly increased the risk of cognitive impairment in subjects (p<0.05). In addition, education
(OR = 0.38) significantly reduced the risk. However, we concluded that age, Malay ethnic, constipation and renal failure
increased the risk of cognitive impairment in subjects but education reduced the risk.
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by deterioration of the brain functions
that result in impairment of memory, cognition and behavioural functions. Oxidative stress is well known to be one of the
causative factors for AD. Thus this disease is potentially modulated by natural antioxidants such as vitamin E. The aim
of this study was to evaluate the effect of tocotrienol-rich fraction (TRF) supplementation on antioxidant enzymes and
DNA damage using APPswe/PS1dE9 transgenic mouse model of AD. Animals were supplemented with TRF (200 mg/kg)
or alpha-tocopherol (αT) (200 mg/kg) for six months starting from nine months old. We found that superoxide dismutase
(SOD) activity in AD mouse was decreased by supplementation of TRF and αT as compared with AD control mouse with no
significant differences in glutathione peroxidise (GPx) activity in all groups. TRF supplementation significantly increased
catalase (CAT) activity. The level of DNA damage of AD mouse shows significant decrease with supplementation of TRF
and αT. In conclusion, TRF was able to modulate antioxidant enzymes activity and decreased the level of DNA damage
of AD transgenic mouse model.
The purpose of this study was to examine the effects of mild cognitive impairment on pattern electroretinogram (pERG)
among urban elderly Malays. A total of 36 subjects aged 60 years and above comprising of 18 MCI subjects and 18
normal controls were recruited for this study. The inclusion criteria for both the MCI and normal subjects included best
corrected distance visual acuity ≥ 6/9 (Snellen) with refractive error less than ±4.00 DS and/or ±2.00 DC (astigmatism),
near visual acuity ≥ N8, absence or no previous history of any significant media opacities, retinal disorders and ocular
pathologies. pERG was recorded with the RetiPort/Scan21 system in accordance with the International Society for the
Clinical Electrophysiology of Vision standards. The target presented to subjects through a 19” CRT monitor was a black
and white reversing checkerboard with luminance equal to 80 cd/m2
, contrast 97% and stimulus frequency 2.00 Hz (4
rev/s). Amplitudes and implicit times of P50 and N95 waves generated by the system were noted and compared between
the two groups. The results showed no significant difference in the amplitude and implicit times between the right and left
eyes so only the right eye was used for comparison between the MCI and control groups. The mean amplitude and implicit
times of the right eye of the MCI and control groups were 1.86±0.65 μV, 56.27±6.20 ms and 1.54±0.74 μV, 56.15±4.98 ms,
respectively. T-test showed no significant differences in pERG amplitudes and implicit times between MCI and the control
groups. In conclusion, our results may imply that the inner retina is intact in early MCI elderly subjects.
There is a lack of population-based data on prevalence of hearing loss in Malaysia. The purpose of this population-based study was to determine the prevalence of hearing loss and its risk factors among 382 older adults aged 60 years and above, recruited through multistage random sampling in Selangor. Hearing level was measured using pure tone audiometry. Hearing loss was classified into at least mild hearing loss and significant hearing loss based on the pure tone average (PTA) of 0.5, 1, 2 and 4 kHz. The examination also included face-to-face interview on hearing related medical history, noise exposure and hearing aid use. Overall, the prevalence of at least mild hearing loss and significant hearing loss were 73.6% (95% CI: 69.4 - 77.4) and 24.6% (95% CI: 20.8 - 28.7), respectively. The odds for at least ‘mild hearing loss’ were male gender, Chinese ethnicity, residing in urban areas, had no formal education or primary school education and history of hypertension. The risk for ‘significant hearing loss’ was significantly higher in males, those who lived in urban areas and elderly with cognitive impairment. Chinese and Indian ethnicities had significantly lower risks than Malay ethnic to have significant hearing loss. Despite the high prevalence of hearing loss, only 4.4% who might benefit from hearing aids wore them. In conclusion, findings from this study show high prevalence of hearing loss among the elderly population. Given the significant association between hearing loss and cognitive impairment, future studies should explore the role of hearing amplification in alleviating or slowing the progress of cognitive decline.
This study examined lactic acid bacteria (LAB)-fermented soymilk for their ability in hydrolyzing glucosides to aglycones
and corresponding antioxidant capacity and memory enhancing effect. Twelve LAB isolated from Malaysian fermented food
and milk products were incubated in commercially available soymilk for 48 h. Generally, soymilk supported LAB growth
and significantly increased (p<0.05) conversion to bioactive aglycone by 2.1-6.5 fold when compared to unfermented
soymilk. Lactobacillus fermentum LAB 9- fermented soymilk, in particular, was presented with increased total phenolic
content (+10%) as opposed to unfermented soymilk. Lactobacilli (LAB 10-12)- and pediococci (LAB 5)-fermented soymilk
elicited maximal DPPH radical-scavenging activity. LAB 1, 7, 8, 9 and 12 exhibited significantly higher (p<0.05) ferrous
ion chelating activity when compared to control. Interestingly, LAB 9 had significantly improved memory deficit (p<0.05)
in LPS-challenged mice. LAB-enriched nutritional value of soymilk could be useful against oxidative stress and memory
deficit.
The continued progression of neurodegeneration may result in dementia. The present study compared the neuroprotective
activities between soybean and tempeh extracts in rats. The extracts were administered orally at 10, 20 and 40 mg/kg for
15 days. Radial arm maze and elevated plus maze served as exteroceptive behavioural models for memory measuring.
Brain cholinergic activities (acetylcholine and acetylcholinesterase) and neuroinflammatory related cytokines interleukin
1β and interleukin-10 were also tested. Soybean and tempeh extracts significantly improved memory, but overall 40 mg/
kg tempeh showed better improvement (p<0.05). The tempeh extracts at 20 and 40 mg/kg exhibited a significant (p<0.05)
increase and decrease in the level of acetylcholine and acetylcholinesterase activities, respectively. Tempeh extract (40
mg/kg) resulted in greater reduction (p<0.05) of inflammation than soybean extract. Altogether, tempeh extract may be
beneficial in the management and prevention of dementia and Alzheimer’s disease.