Displaying publications 21 - 32 of 32 in total

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  1. Purification of lysozyme from chicken egg white using nanofiber membrane immobilized with Reactive Orange 4 dye
    Ng IS, Song CP, Ooi CW, Tey BT, Lee YH, Chang YK
    Int J Biol Macromol, 2019 Aug 01;134:458-468.
    PMID: 31078593 DOI: 10.1016/j.ijbiomac.2019.05.054
    Nanofiber membrane chromatography integrates liquid membrane chromatography and nanofiber filtration into a single-step purification process. Nanofiber membrane can be functionalised with affinity ligands for promoting binding specificity of membrane. Dye molecules are a good affinity ligand for nanofiber membrane due to their low cost and high binding affinity. In this study, a dye-affinity nanofiber membrane (P-Chitosan-Dye membrane) was prepared by using polyacrylonitrile nanofiber membrane modified with chitosan molecules and immobilized with dye molecules. Reactive Orange 4, commercially known as Procion Orange MX2R, was found to be the best dye ligand for membrane chromatography. The binding capacity of P-Chitosan-Dye membrane for lysozyme was investigated under different operating conditions in batch mode. Furthermore, desorption of lysozyme using the P-Chitosan-Dye membrane was evaluated systematically. The recovery percentage of lysozyme was found to be ~100%. The optimal conditions obtained from batch-mode study were adopted to develop a purification process to separate lysozyme from chicken egg white. The process was operated continuously using the membrane chromatography and the characteristic of the breakthrough curve was evaluated. At a lower flow rate (i.e., 0.1 mL/min), the total recovery of lysozyme and purification factor of lysozyme were 98.59% and 56.89 folds, respectively.
  2. Enhancement of C-phycocyanin purity using negative chromatography with chitosan-modified nanofiber membrane
    Ng IS, Tang MSY, Show PL, Chiou ZM, Tsai JC, Chang YK
    Int J Biol Macromol, 2019 Jul 01;132:615-628.
    PMID: 30940588 DOI: 10.1016/j.ijbiomac.2019.03.235
    In this work, a chitosan-modified nanofiber membrane was fabricated and used to examine the permeation characteristics of C-phycocyanin (CPC) obtained from Spirulina platensis. The effects of NaCl concentration (0.1-1.0 M), chitosan coupling pH (6-8), chitosan coupling concentration (0.1-3.0%), algal solution pH (6-8), algal mass concentration (0.1-1.0% dw/v), and membrane flux (4.08 × 10-2-2.04 × 10-1 mL/min·cm2) on the penetration performance of the membrane for CPC were investigated. The results show that the order of binding selectivity of the membrane for these proteins is contaminating proteins (TP) > allophycocyanin (APC) > CPC. TP and APC molecules were more easily adsorbed by the chitosan-modified membrane, and the CPC molecules most easily penetrated the membrane without being adsorbed, enhancing CPC purity. The purification factor and total mass flux were 3.3 fold and 66%, respectively, in a single step.
  3. Antibacterial efficacy of chitosan- and poly(hexamethylene biguanide)-immobilized nanofiber membrane
    Ng IS, Ooi CW, Liu BL, Peng CT, Chiu CY, Chang YK
    Int J Biol Macromol, 2020 Jul 01;154:844-854.
    PMID: 32194127 DOI: 10.1016/j.ijbiomac.2020.03.127
    In this study, polyacrylonitrile (PAN) nanofiber membrane was prepared by an electrospinning technique. After alkaline hydrolysis, the ion-exchange nanofiber membrane (P-COOH) was grafted with chitosan molecules to form a chitosan-modified nanofiber membrane (P-COOH-CS). Poly(hexamethylene biguanide) (PHMB) was then covalently immobilized on P-COOH and P-COOH-CS to form P-COOH-PHMB and P-COOH-CS-PHMB, respectively. The nanofiber membranes were subjected to various surface analyses as well as to the evaluations of antibacterial activity against Escherichia coli. The optimal modification conditions for P-COOH-CS-PHMB were attained by water-soluble chitosan at 50 kDa of molecular weight, coupling pH at 7, and 0.05% (w/w) of PHMB. Within 10 min of treatment, the antibacterial rate was close to 100%. Under the similar conditions of antibacterial treatment, the P-COOH-CS-PHMB exhibited a better antibacterial efficacy than the P-COOH-PHMB. When the number of bacterial cells was increased by 2000 folds, both types of nanofiber membranes still maintained the antibacterial rate close to 100%. After five cycles of repeated antibacterial treatment, the antibacterial efficacy of P-COOH-PHMB was 96%, which was higher than that of P-COOH-CS-PHMB (83%). The experimental results revealed that the PHMB-modified nanofiber membranes can be suitably applied in water treatment such as water disinfection and biofouling control.
  4. Fulltext Relationship between Mindfulness, Psychological Skills, and Mental Toughness in College Athletes
    Wu CH, Nien JT, Lin CY, Nien YH, Kuan G, Wu TY, et al.
    Int J Environ Res Public Health, 2021 06 24;18(13).
    PMID: 34202770 DOI: 10.3390/ijerph18136802
    Numerous studies have shown that dispositional mindfulness is positively associated with many mental abilities related to sports performance, including psychological skills and mental toughness. The purpose of this study was to explore the relationship between dispositional mindfulness, psychological skills, and mental toughness among different types of athletes. For this cross-sectional study, 101 college athletes were recruited. Their dispositional mindfulness, psychological skills, and mental toughness were measured by the Mindfulness Attention Awareness Scale (MAAS), Athletic Psychological Skills Inventory (APSI), and Traits of Mental Toughness Inventory for Sports Scale (TMTIS). Pearson's correlation was used to calculate how dispositional mindfulness is associated with psychological skills and mental toughness. The results revealed that dispositional mindfulness is positively associated with comprehensive APSI (r = 0.21-0.36, p < 0.05), TMTIS overall (r = 0.27, p < 0.01), positive effort (r = 0.26, p = 0.01), and pressure (r = 0.30, p < 0.01). These findings suggest a positive linkage between mindfulness and the two examined psychological characteristics related to sports performance. Other approaches to increase mindfulness may be considered in the future.
  5. Fulltext Effects of Brain Breaks videos on the motives for the physical activity of Malaysians with type-2 diabetes mellitus
    Hidrus A, Kueh YC, Norsaádah B, Chang YK, Hung TM, Naing NN, et al.
    Int J Environ Res Public Health, 2020 04 06;17(7).
    PMID: 32268601 DOI: 10.3390/ijerph17072507
    Brain Breaks videos are web-based structured physical activity (PA) videos that aim at stimulating an interest in learning and promoting health. Exercise is one of the important treatment regimens for people with type 2 diabetes mellitus (T2DM). Thus, the objective of this study was to determine the effects that Brain Breaks videos have on the motives for PA, as measured by the Physical Activity and Leisure Motivation Scale-Malay (PALMS-M), and the amount of PA, as measured by the International Physical Activity Questionnaire-Malay (IPAQ-M), in T2DM patients (the most common type of diabetes mellitus patients). This study was conducted using a randomized, double-blind design and grouped subjects under two research conditions: an experimental group given Brain Breaks videos and a control group. Purposive sampling was employed to recruit 70 T2DM patients (male = 39, female = 31) with the mean age of 57.6 (SD = 8.5) from Hospital Universiti Sains Malaysia, Kelantan. Over a four-month period, the participants in the experimental group were asked to perform PA daily based on a Brain Breaks video (10 min in duration) that was shared through a WhatsApp group. All participants from both groups answered the PALMS-M questionnaire five times: pre-intervention, the end of the first month, second month, and third month, and post-intervention. A repeated measure multivariate analysis of variance and a repeated measure analysis of variance were performed for the analyses of the data. The results demonstrated that four (appearance, others' expectations, physical condition, and mastery) out of eight motives for PA produced a significant mean score difference between the two study groups. All eight motives for PA showed an upward trend for the experimental group during the study period, while the control group showed a downward trend for all motives during the study period. As for the amount of PA, both groups showed significant differences (p = 0.001). The amount of PA increased in the experimental group during the study period, while it decreased in the control group. Therefore, Brain Breaks videos can be considered as an effective intervention for motivating T2DM patients for PA and improving their amount of PA.
  6. Fulltext Effects of Brain Breaks Video Intervention of Decisional Balance among Malaysians with Type 2 Diabetes Mellitus: A Randomised Controlled Trial
    Hidrus A, Kueh YC, Norsa'adah B, Chang YK, Kuan G
    Int J Environ Res Public Health, 2021 08 26;18(17).
    PMID: 34501562 DOI: 10.3390/ijerph18178972
    Brain Breaks® are structured physical activity (PA) web-based videos designed to promote an interest in learning and health promotion. The objective of this study was to examine its effects on decision balance (DB) which consists of the perceived benefits (Pros) and perceived barriers (Cons) of exercise in people with type 2 diabetes mellitus (T2DM). A randomised controlled trial was conducted among people with T2DM at Hospital Universiti Sains Malaysia. The intervention group received Brain Breaks videos for a period of four months. The intervention and control groups completed the validated Malay version of DB questionnaire for five times, at pre-intervention, the first month, the second month, the third month, and post-intervention. Multivariate Repeated Measures Analysis of Variance was performed for data analysis. A total of 70 participants were included (male = 39; female = 31) with a mean age of 57.6 years (SD = 8.5). The intervention group showed a significant change in the Pros and Cons factors of DB scores over time. The intervention group showed significantly higher scores for the Pros (p-value < 0.001) and lower scores for the Cons (p-value = 0.008) factors than the control group. In conclusion, the Brain Breaks video is an effective intervention to improve decisional balance in patients with T2DM to help them in deciding on behaviour change to be more physically active.
  7. Fulltext Staying Active under Restrictions: Changes in Type of Physical Exercise during the Initial COVID-19 Lockdown
    Benzing V, Nosrat S, Aghababa A, Barkoukis V, Bondarev D, Chang YK, et al.
    Int J Environ Res Public Health, 2021 11 16;18(22).
    PMID: 34831770 DOI: 10.3390/ijerph182212015
    The COVID-19 pandemic and the associated governmental restrictions suddenly changed everyday life and potentially affected exercise behavior. The aim of this study was to explore whether individuals changed their preference for certain types of physical exercise during the pandemic and to identify risk factors for inactivity. An international online survey with 13,881 adult participants from 18 countries/regions was conducted during the initial COVID-19 related lockdown (between April and May 2020). Data on types of exercise performed during and before the initial COVID-19 lockdown were collected, translated, and categorized (free-text input). Sankey charts were used to investigate these changes, and a mixed-effects logistic regression model was used to analyze risks for inactivity. Many participants managed to continue exercising but switched from playing games (e.g., football, tennis) to running, for example. In our sample, the most popular exercise types during the initial COVID-19 lockdown included endurance, muscular strength, and multimodal exercise. Regarding risk factors, higher education, living in rural areas, and physical activity before the COVID-19 lockdown reduced the risk for inactivity during the lockdown. In this relatively active multinational sample of adults, most participants were able to continue their preferred type of exercise despite restrictions, or changed to endurance type activities. Very few became physically inactive. It seems people can adapt quickly and that the constraints imposed by social distancing may even turn into an opportunity to start exercising for some. These findings may be helpful to identify individuals at risk and optimize interventions following a major context change that can disrupt the exercise routine.
  8. Fulltext Effects of Multi-Component Exercise on Sleep Quality in Middle-Aged Adults
    Ai JY, Kuan G, Juang LY, Lee CH, Kueh YC, Chu IH, et al.
    Int J Environ Res Public Health, 2022 Nov 22;19(23).
    PMID: 36497548 DOI: 10.3390/ijerph192315472
    Sleep is a crucial factor in healthy aging. However, most middle-aged adults experience high levels of sleep disorders. While previous findings have suggested exercise training could benefit the quality of sleep, the effects of multi-component exercise on sleep quality are less examined. Accordingly, the current study aimed to assess the effectiveness of a multi-component exercise program on the quality of sleep among middle-aged adults. Twenty-four middle-aged adults were randomly assigned either to a multi-component exercise (MCE) group or a control group. The participants in the MCE group attended a 90-min session per week for 12 weeks. The control group was instructed to maintain their daily routine for 12 weeks. The primary outcome was the sleep quality evaluated by the Pittsburgh Sleep Quality Index (PSQI). The secondary outcome was physical fitness, including muscular strength and endurance, balance, and flexibility. Regarding sleep quality, the global mean score (p = 028), sleep disturbances (p = 011), and sleep efficiency (p = 035) of the PSQI scores were significantly reduced in the MCE group after the 12-week intervention. Regarding physical fitness, the flexibility of the MCE group improved significantly after the intervention (p = 028), yet, no significant change was observed in the control group. Additionally, the muscular strength of the control group declined significantly after the 12-week period (p = 034). Our results revealed the effectiveness of the MCE intervention in improving sleep quality and physical fitness in middle-aged adults. Further studies using larger sample sizes, objective measures of sleep quality, different types of exercise training, as well as different populations, are warranted to extend our current findings.
  9. Direct recovery of malate dehydrogenase from highly turbid yeast cell homogenate using dye-ligand affinity chromatography in stirred fluidized bed
    Chen KH, Lee SY, Show PL, Hong SC, Chang YK
    J Chromatogr B Analyt Technol Biomed Life Sci, 2018 Nov 15;1100-1101:65-75.
    PMID: 30292951 DOI: 10.1016/j.jchromb.2018.09.039
    Dye-ligand affinity chromatography in a stirred fluidized bed has been developed for the rapid recovery of malate dehydrogenase (MDH) from highly turbid baker's yeast cell homogenate in a single step. The most suitable dye, namely Reactive Orange 4, in its optimal immobilized concentration of 8.78 mg/mL was immobilized onto high-density STREAMLINE matrix. To further examine optimal adsorption and elution conditions, the enzyme recovery operation was carried out using unclarified cell homogenates in stirred fluidized bed system. Aiming to develop a non-specific eluent, namely NaCl, to effectively elute the MDH adsorbed, direct recovery of MDH from highly turbid cell homogenate (50% w/v) in a stirred fluidized bed adsorption system was performed. The proposed system successfully achieved a recovery yield of 73.6% and a purification factor of 73.5 in a single step by using 0.6 M NaCl as an eluent at a high liquid velocity of 200 cm/h.
  10. Fulltext Kinetic and Thermodynamic Studies of Lysozyme Adsorption on Cibacron Blue F3GA Dye-Ligand Immobilized on Aminated Nanofiber Membrane
    Hsin A, How SC, Wang SS, Ooi CW, Chiu CY, Chang YK
    Membranes (Basel), 2021 Dec 07;11(12).
    PMID: 34940464 DOI: 10.3390/membranes11120963
    The polyacrylonitrile (PAN) nanofiber membrane was prepared by the electrospinning technique. The nitrile group on the PAN nanofiber surface was oxidized to carboxyl group by alkaline hydrolysis. The carboxylic group on the membrane surface was then converted to dye affinity membrane through reaction with ethylenediamine (EDA) and Cibacron Blue F3GA, sequentially. The adsorption characteristics of lysozyme onto the dye ligand affinity nanofiber membrane (namely P-EDA-Dye) were investigated under various conditions (e.g., adsorption pH, EDA coupling concentration, lysozyme concentration, ionic strength, and temperature). Optimum experimental parameters were determined to be pH 7.5, a coupling concentration of EDA 40 μmol/mL, and an immobilization density of dye 267.19 mg/g membrane. To understand the mechanism of adsorption and possible rate controlling steps, a pseudo first-order, a pseudo second-order, and the Elovich models were first used to describe the experimental kinetic data. Equilibrium isotherms for the adsorption of lysozyme onto P-EDA-Dye nanofiber membrane were determined experimentally in this work. Our kinetic analysis on the adsorption of lysozyme onto P-EDA-Dye nanofiber membranes revealed that the pseudo second-order rate equation was favorable. The experimental data were satisfactorily fitted by the Langmuir isotherm model, and the thermodynamic parameters including the free energy change, enthalpy change, and entropy change of adsorption were also determined accordingly. Our results indicated that the free energy change had a negative value, suggesting that the adsorption process occurred spontaneously. Moreover, after five cycles of reuse, P-EDA-Dye nanofiber membranes still showed promising efficiency of lysozyme adsorption.
  11. Fulltext Removal of Ionic Dyes by Nanofiber Membrane Functionalized with Chitosan and Egg White Proteins: Membrane Preparation and Adsorption Efficiency
    Chen YS, Ooi CW, Show PL, Hoe BC, Chai WS, Chiu CY, et al.
    Membranes (Basel), 2022 Jan 01;12(1).
    PMID: 35054589 DOI: 10.3390/membranes12010063
    Electrospun polyacrylonitrile (PAN) nanofiber membrane was functionalized with chitosan and proteins for use in the treatment of dye-containing wastewater. The PAN nanofiber membrane was subjected to alkaline hydrolysis, before being grafted with chitosan and subsequently the proteins from chicken egg white. The resultant nanofiber membrane (P-COOH-CS-CEW) was comprehensively characterized using thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The efficiency of P-COOH-CS-CEW in removing cationic dye toluidine blue O (TBO) and anionic dye acid orange 7 (AO7) in aqueous solution was evaluated. Based on the performance of model fitting, Langmuir and pseudo-second-order kinetic model could be used to describe the performance of P-COOH-CS-CEW in the removal of TBO (pH 10) and AO7 (pH 2) from the dye solutions. The adsorbed TBO and AO7 dyes can be completely desorbed by an elution solution made of 50% (v/v) ethanol and 1 M sodium chloride. After five consecutive adsorption-desorption cycles, the efficiency of dye removal by P-COOH-CS-CEW was maintained above 97%.
  12. Fulltext Structural equation model of psychological constructs of transtheoretical model, motives for physical activity, and amount of physical activity among people with type 2 diabetes mellitus in Malaysia
    Hidrus A, Kueh YC, Norsa'adah B, Kim Y, Chang YK, Kuan G
    PLoS One, 2022;17(3):e0266104.
    PMID: 35358248 DOI: 10.1371/journal.pone.0266104
    BACKGROUND: This study aimed determine the structural relationship between psychological constructs of the transtheoretical model (TTM; processes of change, decisional balance, and exercise self-efficacy), motives for physical activity (PA), and amount of PA among Malaysians with type 2 diabetes mellitus (T2DM).

    METHOD: All participants were recruited from the Hospital Universiti Sains Malaysia using a cross-sectional study design with purposive) sampling method. A total of 331 participants were recruited for the present study. Before participation in the study, they were informed that participation in the study was totally voluntary. Those who agreed to participate voluntarily were required to complete the self-administered questionnaire set, which included the processes of change, decisional balance, exercise self-efficacy, physical activity and leisure motivation, and international physical activity questionnaires. Data analysis of structural equation modeling was performed using Mplus 8.

    RESULTS: From the 331 participants, most of whom were male (52%) and Malay (89.4%), with a mean age of 62.6 years (standard deviation = 10.29). The final structural equation model fit the data well based on several fit indices [Root Mean Square Error of Approximation (RMSEA) = 0.059, Comparative Fit Index (CFI) = 0.953, Tucker-Lewis Index (TLI) = 0.925, Standardized Root Mean Square Residual (SRMR) = 0.031]. A total of 16 significant path relationships linked between the TTM, motives for PA, and amount of PA.

    CONCLUSION: The pros of decisional balance, others' expectations, and psychological condition were constructs that directly affected PA, whereas the other constructs had a significant indirect relationship with the amount of PA. A positive mindset is crucial in deciding a behavioral change toward an active lifestyle in people with T2DM.

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