Displaying publications 441 - 460 of 1883 in total

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  1. Mugilan Muralitharan, Syed Ahmad Helmi, Kamarulafizam Ismail, Azanizawati Ma'aram
    MyJurnal
    Aesthetic value of the automotive car seat has been one of the selling points of each car besides
    providing functions such as being safe, supportive as well provides comfort to the occupants. Other
    criteria considered besides the aesthetic element are cushion foam and self-adjustment factor.
    Ergonomics is not a new issue because most of the existing seat design today have already practiced it.
    Existing car seat manufacturers have considered anthropometry data. The average upon 95th percentile of
    human measurement had been deliberated. However, issues such as time spent driving and seat design
    issue have arisen upon the search of comfort and rising of musculoskeletal disease such as back pain. As a
    solution, this study would propose an automotive car seat design of ergonomic evolution, which would
    create comfort by manipulating the seat cushion foams. The proposed seat cushion foam would be use to
    replace the existing polymers with beanbag foam. This is inspire by the nature of beanbag, fitting up and
    providing comfort to the occupants of various body sizes and shapes. Malaysian anthropometry
    measurements are required for design of car seat, which later compared with the existing seats of
    commercial vehicle. The literature review showed the pressure mapping technique of respondent seating
    on the existing car seat. The most sensitive compartments where discomfort are experienced studied and
    placed with sachets filed with beanbag beads. This experiment conducted many times over a few
    respondents by using the pressure mat to find out, if there are any changes in terms of comfort. This
    design of new car seat with a manipulation cushion foam replaced with beanbag foam could be a niche to
    eliminate discomfort to all range body sizes and shapes.
    Matched MeSH terms: Pressure
  2. Mazlinda, M., Ayu Sulaini, J., Suriawati, G., Mardiana, M., Zahri, M.K.
    MyJurnal
    A pressure ulcer is a common health problem, particularly among the physically limited or bedridden individuals. The most vulnerable group to suffer this condition is the elderly. The prevalence of Geriatric inpatient with pressure ulcer stage I, II, III or even IV for a month was 35.5% of the total admission. The understanding of recovery process, prevention remains the best management strategy as it improves their quality of life. This study aims to compare PU development outcomes in geriatric patients nursed on either using the Durable barrier cream (Cavillon cream) or non-pharmacological intervention alone. Using the Quasi experimental study-design, the selected participants were subjected to Cavaillon cream as well as the intervention. The assessment used were the outcome of the pressure ulcer was assessed using the measured size of the redness area. There was the statistically significant reduction in pressure ulcer size on day three compared to the size on day one among the intervention group, z value was -5.028, p
    Matched MeSH terms: Pressure Ulcer
  3. Major VJ, Chiew YS, Shaw GM, Chase JG
    Biomed Eng Online, 2018 Nov 12;17(1):169.
    PMID: 30419903 DOI: 10.1186/s12938-018-0599-9
    BACKGROUND: Mechanical ventilation is an essential therapy to support critically ill respiratory failure patients. Current standards of care consist of generalised approaches, such as the use of positive end expiratory pressure to inspired oxygen fraction (PEEP-FiO2) tables, which fail to account for the inter- and intra-patient variability between and within patients. The benefits of higher or lower tidal volume, PEEP, and other settings are highly debated and no consensus has been reached. Moreover, clinicians implicitly account for patient-specific factors such as disease condition and progression as they manually titrate ventilator settings. Hence, care is highly variable and potentially often non-optimal. These conditions create a situation that could benefit greatly from an engineered approach. The overall goal is a review of ventilation that is accessible to both clinicians and engineers, to bridge the divide between the two fields and enable collaboration to improve patient care and outcomes. This review does not take the form of a typical systematic review. Instead, it defines the standard terminology and introduces key clinical and biomedical measurements before introducing the key clinical studies and their influence in clinical practice which in turn flows into the needs and requirements around how biomedical engineering research can play a role in improving care. Given the significant clinical research to date and its impact on this complex area of care, this review thus provides a tutorial introduction around the review of the state of the art relevant to a biomedical engineering perspective.

    DISCUSSION: This review presents the significant clinical aspects and variables of ventilation management, the potential risks associated with suboptimal ventilation management, and a review of the major recent attempts to improve ventilation in the context of these variables. The unique aspect of this review is a focus on these key elements relevant to engineering new approaches. In particular, the need for ventilation strategies which consider, and directly account for, the significant differences in patient condition, disease etiology, and progression within patients is demonstrated with the subsequent requirement for optimal ventilation strategies to titrate for patient- and time-specific conditions.

    CONCLUSION: Engineered, protective lung strategies that can directly account for and manage inter- and intra-patient variability thus offer great potential to improve both individual care, as well as cohort clinical outcomes.

    Matched MeSH terms: Positive-Pressure Respiration/instrumentation*; Positive-Pressure Respiration/methods; Pressure
  4. Sharuddin Mohd Dahuri, Nor Hakimah Ahmad Subri, Norashady Mohd Noor
    MyJurnal
    his paper presents the structure and static model of engine camshaft analysis. For the purposes of this analysis, the finite element method is used. Camshaft is one of the critical components for effective and precise work of internal combustion engines. This camshaft rotates at high speed causing pressure and vibration in the system. Camshafts are also subject to varying fatigue burden due to cam plunger contact. These precise values are required to be determined to prevent failure in the camshaft. The objective of the project is to model and to perform pressure analysis on the camshaft machine. In this project the standard engine cam shafts are modeled and analyzed using the CATIA V5R21 software respectively. This model is created by the basic requirements of the engine. It is done with an existing background, such as the power of acting on cam by means of a valve while running at maxi mum speed. Here the approach becomes fully CAE based. CAE - based approaches enrich Research and limit the time span. A study was conducted to predict the behavior of the different camshafts structure of the material using the finite three - dimensional pressure of the element. Four types of materials such as Steel, Titanium, Aluminum and Magnesium are taken into account. FEA Stress and maximum displacement decisions are calculated and compared to all of the above materials. The conclusion is to focus on the material suitable for the camshaft to reduce the maximum displacement and weight. Titanium materials become the best material for camshaft manufacturing based on analysis.
    Matched MeSH terms: Pressure
  5. Bayat M, Alarifi IM, Khalili AA, El-Bagory TMAA, Nguyen HM, Asadi A
    Sci Rep, 2019 Oct 25;9(1):15317.
    PMID: 31653877 DOI: 10.1038/s41598-019-51450-z
    A thermo-elastic contact problem of functionally graded materials (FGMs) rotating brake disk with different pure brake pad areas under temperature dependent material properties is solved by Finite Element Method (FEM). The properties of brake disk change gradually from metal to ceramic by power-law distribution along the radial direction from the inner to the outer surface. Areas of the pure pad are changing while the vertical force is constant. The ratio of brake pad thickness to FGMs brake disk thickness is assumed 0.66. Two sources of thermal loads are considered: (1) Heat generation between the pad and brake disk due to contact friction, and (2) External thermal load due to a constant temperature at inner and outer surfaces. Mechanical responses of FGMs disk are compared with several pad contact areas. The results for temperature-dependent and temperature-independent material properties are investigated and presented. The results show that the absolute value of the shear stress in temperature-dependent material can be greater than that for temperature-independent material. The radial stress for some specific grading index (n = 1.5) is compressive near the inner surface for double contact while it is tensile for a single contact. It is concluded that the radial strain for some specific value of grading index (n = 1) is lower than other FGMs and pure double side contact brake disks.
    Matched MeSH terms: Pressure
  6. MUHAMMAD ILMAN HAKIMI CHUA, ABU BAKAR SULONG, MOHD FAZURI ABDULLAH, NORHAMIDI MUHAMAD
    Sains Malaysiana, 2013;42:1743-1750.
    In this study, injection molding parameters, including green strength, surface quality and green part density, were optimized using the L18 Taguchi orthogonal array. The L25 Taguchi method was used to optimize the green density of solvent debinding parameters. The feedstock consisted of stainless steel powder (SS316L), with powder loading fractions of 63, 63.5 and 64 v/o. The binder compositions used in the study were polyethelene glycol (PEG-73 wt. %), polymethyl methacrilate (PMMA-25 wt. %) and stearic acid (2 wt. %). The Taguchi method was used to optimize the injection parameters. The obtained optimum parameters were as follows: mold temperature of 65oC, injection temperature of 145oC, injection pressure of 650 bar, injection flow rate of 20 m3/s, holding time of 5 s and powder loading of 64% v/o. Analysis of variance results showed that mold temperature has the greatest influence in the production of good green part surface quality and that powder loading gave the best green part strength. Immersion time and temperature were used to optimize for solvent debinding parameters. By optimizing the solvent debinding parameters, an immersion temperature of 61oC and immersion time of 5 h produced the highest density which is the optimum value gain in this study.
    Matched MeSH terms: Pressure
  7. Hayat T, Abbasi F, Ahmad B, Alsaedi A
    Sains Malaysiana, 2014;43:1583-1590.
    This article concerns with a mixed convection peristaltic flow of an electrically conducting fluid in an inclined asymmetric channel. Analysis has been carried out in the presence of Joule heating. The fluid viscosity and thermal conductivity are assumed to vary as a linear function of temperature. A nonlinear coupled governing system is computed. Numerical results were presented for the velocity, pressure gradient, temperature and streamlines. Heat transfer rate at the wall is computed and analyzed. Graphs reflecting the contributions of embedded parameters were discussed.
    Matched MeSH terms: Pressure
  8. Peter A.G. Cormack, Faizatul Shimal Mehamod
    Sains Malaysiana, 2013;42:529-535.
    In this paper, the synthesis and characterisation of caffeine-imprinted polymers are described. The polymers were prepared in monolithic form via both reversible addition-fragmentation chain-transfer (RAFT) polymerisation and conventional free radical polymerisation, using methacrylic acid and ethylene glycol dimethacrylate as the functional monomer and crosslinking agent, respectively. The potential benefits in applying RAFT polymerisation techniques towards the synthesis of molecularly imprinted polymers (MIPs) are explored and elucidated. The pore structures of the polymers produced were characterised by nitrogen sorption porosimetry and the molecular recognition properties of representative products were evaluated in high-performance liquid chromatography (HPLC) mode. Molecular imprinting effects were confirmed by analysing the relative retentions of analytes on imprinted and non-imprinted HPLC
    stationary phases. It was found that a caffeine-imprinted polymer synthesised by RAFT polymerisation was superior to a polymer prepared using a conventional synthetic approach; the imprinting factor and column efficiency were found to be higher for the former material.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  9. Zakaria AF, Tsuji M
    Malays Orthop J, 2019 Nov;13(3):85-87.
    PMID: 31890118 DOI: 10.5704/MOJ.1911.016
    Intracranial subdural hematoma following lumbar surgery is a devastating but rare complication. It has been implicated due to intracranial hypotension secondary to persistent cerebrospinal fluid leakage. The resultant drop in intracranial pressure presumably causes traction and tearing of venous structures. Patients typically present with postural headaches. However, other symptoms of subdural hematoma, intracranial hypotension and cerebrospinal fluid leak must also be cautioned.
    Matched MeSH terms: Intracranial Pressure
  10. Ang WL, Mohammad AW, Johnson D, Hilal N
    Sci Total Environ, 2020 Mar 01;706:136047.
    PMID: 31864996 DOI: 10.1016/j.scitotenv.2019.136047
    Study of forward osmosis (FO) has been increasing steadily over recent years with applications mainly focusing on desalination and wastewater treatment processes. The working mechanism of FO lies in the natural movement of water between two streams with different osmotic pressure, which makes it useful in concentrating or diluting solutions. FO has rarely been operated as a stand-alone process. Instead, FO processes often appear in a hybrid or integrated form where FO is combined with other treatment technologies to achieve better overall process performance and cost savings. This article aims to provide a comprehensive review on the need for hybridization/integration for FO membrane processes, with emphasis given to process enhancement, draw solution regeneration, and pretreatment for FO fouling mitigation. In general, integrated/hybrid FO processes can reduce the membrane fouling propensity; prepare the solution suitable for subsequent value-added uses and production of renewable energy; lower the costs associated with energy consumption; enhance the quality of treated water; and enable the continuous operation of FO through the regeneration of draw solution. The future potential of FO lies in the success of how it can be hybridized or integrated with other technologies to minimize its own shortcomings, while enhancing the overall performance.
    Matched MeSH terms: Osmotic Pressure
  11. Manju K
    Family Physician, 1994;6:6-8.
    Hypertensive disorders of pregnancy is a major cause of fetal and maternal morbidity. Epidemiologic observations have shown an inverse association between calcium intake and incidence of eclampsia. Calcium supplementation has been reported to decrease blood pressure in pregnant women, although this remains controversial. The mechanism responsible for the effect of calcium on hypertinsion in pregnant women is unknown. This paper is a review of some of the recent calcium supplementation trials that have been carried out and their effectiveness in reducing systolic and diastolic blood pressure and decreasing the incidence of hypertensive disorders of pregnancy.
    Matched MeSH terms: Blood Pressure
  12. Mutafi A, Yidris N, Ishak MR, Zahari R
    Heliyon, 2018 Nov;4(11):e00937.
    PMID: 30839801 DOI: 10.1016/j.heliyon.2018.e00937
    Steel sections are normally shaped via cold work manufacturing processes. The extent of cold work to shape the steel sections might induce residual stresses in the region of bending. Previously, researchers had performed studies on the influences of local buckling on the failure behavior of steel compression members which shown that failure will happen when most of the yielding has extended to the middle surface in the bend region of the sections. Therefore, these cold work methods may have major effect on the behavior of the steel section and also its load-bearing capability. In addition, another factor may play significant role in formed section's load-bearing capacity which is the longitudinal residual strain. The longitudinal residual strain raised during forming procedure can be used to define the section imperfection of the formed section and its relation to the existence of defects. Therefore, the main motivation of this research paper is to perform three-dimensional finite element (3D-FE) to investigate peak longitudinal residual strains of a thin-walled steel plate with large bending angle along member length. A 3D finite element simulation in ABAQUS has been employed to simulate this forming process. The study concluded that the longitudinal residual strain at the section corner edge was higher than those at the rest of the corner region. These strains at the edge were higher than the yield strain


    (



    ε


    y



    )


    of the formed section which occurred due to the lack of transverse restraint. This made the plate edge tended to bend toward the normal direction when it was under a high transverse bending. This causes a significant difference in longitudinal strain at the plate edge.
    Matched MeSH terms: Pressure
  13. Aeinehvand MM, Weber L, Jiménez M, Palermo A, Bauer M, Loeffler FF, et al.
    Lab Chip, 2019 Feb 20.
    PMID: 30785443 DOI: 10.1039/c8lc00849c
    Reversible valves on centrifugal microfluidic platforms facilitate the automation of bioanalytical assays, especially of those requiring a series of steps (such as incubation) in a single reaction chamber. In this study, we present fixed elastic reversible (FER) valves and tunable elastic reversible (TER) valves that are easy to fabricate, implement and control. In the FER valve the compression of an elastic barrier/patch against a microchamber's outlet prevents the release of liquid. The valve sealing pressure was determined by adjusting the engraving depth of the valve-seat at which the elastic patch was located, this allows to set the sealing pressure during disc fabrication. In the TER valve, the patch compression value and sealing pressure is controlled by the penetration depth of a plastic screw into the valve-seat. The ER valves prevent liquid flow until the centrifugal force overcomes their sealing pressure. Moreover, at a constant spin speed, turning the screw of a TER valve reduces its sealing pressure and opens the valve. Therefore, the TER valve allows for controlling of the liquid transfer volume at various spin speeds. The FER and TER valves' behavior is mathematically described and equations for the prediction of their operation under centrifugal forces are provided. As a point-of-care (POC) application of ER valves, we have developed a microfluidic disc with a series of TER valves and peptide microarrays for automated multiplexed detection of five different proteins from a single serum sample.
    Matched MeSH terms: Pressure
  14. Ruzita AT, Osman A, Khalid AK
    Family Physician, 1994;6:12-14.
    The aim of the study was to determine the factors associated with diabetic control among Non Insulin Dependent Diabetes Mellitus (NIDDM) in a Felda settlement area. METHODS: We analyzed the anthropometric and metabolic data of sixty three NIDDM patients in Felda Sg Koyan, Raub, Pahang. Diabetic control, was measured by glycated hemoglobin (HbA1) and fructosamine; it showed a strong correlation (r=12.8 and p-0.001). With the use of a multivariate regression model, which was adjusted for sex, age, dhration of diabetes, body mass index (BMI) and systolic blood pressure, we found that the occurrence of higher fructosamine was associated with significantly higher HbA1 (F =7.8, p=0.01). RESULTS: Obesity was present in 72% of diabetic patients with BMI>25 and had a mean duration of diabetes of 6+4 years. Mean HbAl among males (6.8 + 1.6%) were significantly different (p 0.05) to diabetic control. CONCLUSIONS: The study showed that males have a better diabetic control than females. Poor control was observed among diabetics who had diabetes for more than five years.
    Matched MeSH terms: Blood Pressure
  15. Aziz F, Malek S, Mhd Ali A, Wong MS, Mosleh M, Milow P
    PeerJ, 2020;8:e8286.
    PMID: 32206445 DOI: 10.7717/peerj.8286
    Background: This study assesses the feasibility of using machine learning methods such as Random Forests (RF), Artificial Neural Networks (ANN), Support Vector Regression (SVR) and Self-Organizing Feature Maps (SOM) to identify and determine factors associated with hypertensive patients' adherence levels. Hypertension is the medical term for systolic and diastolic blood pressure higher than 140/90 mmHg. A conventional medication adherence scale was used to identify patients' adherence to their prescribed medication. Using machine learning applications to predict precise numeric adherence scores in hypertensive patients has not yet been reported in the literature.

    Methods: Data from 160 hypertensive patients from a tertiary hospital in Kuala Lumpur, Malaysia, were used in this study. Variables were ranked based on their significance to adherence levels using the RF variable importance method. The backward elimination method was then performed using RF to obtain the variables significantly associated with the patients' adherence levels. RF, SVR and ANN models were developed to predict adherence using the identified significant variables. Visualizations of the relationships between hypertensive patients' adherence levels and variables were generated using SOM.

    Result: Machine learning models constructed using the selected variables reported RMSE values of 1.42 for ANN, 1.53 for RF, and 1.55 for SVR. The accuracy of the dichotomised scores, calculated based on a percentage of correctly identified adherence values, was used as an additional model performance measure, resulting in accuracies of 65% (ANN), 78% (RF) and 79% (SVR), respectively. The Wilcoxon signed ranked test reported that there was no significant difference between the predictions of the machine learning models and the actual scores. The significant variables identified from the RF variable importance method were educational level, marital status, General Overuse, monthly income, and Specific Concern.

    Conclusion: This study suggests an effective alternative to conventional methods in identifying the key variables to understand hypertensive patients' adherence levels. This can be used as a tool to educate patients on the importance of medication in managing hypertension.

    Matched MeSH terms: Blood Pressure
  16. Ghani Z, Anuar A, Majid Z, Yoneda M
    Sains Malaysiana, 2017;46:2383-2392.
    This study describes the development of a multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT) at Sungai Sayong watershed. Based on the latest estimated DDT emission, the DDT concentrations in air, soil, water and sediment as well as the transfer processes were simulated under the equilibrium and steady-state assumption. Model predictions suggested that soil and sediment was the dominant sink of DDT. The results showed that the model predicted was generally good agreement with field data. Compared with degradation reaction, advection outflow was more important processes occurred in the model. Sensitivities of the model estimates to input parameters were tested. The result showed that vapour pressure (Ps) and organic carbon water partition coefficient (KOC) were the most influential parameters for the model output. The model output-concentrations of DDT in multimedia environment is very important as it can be used in future for human exposure and risk assessment of organochlorine pesticides (OCPs) at Sungai Sayong Basin.
    Matched MeSH terms: Vapor Pressure
  17. Noor Zuhartini Md Muslim, Musa Ahmad, Lee YH, Bahruddin Saad
    Sains Malaysiana, 2018;47:707-713.
    An optical fiber chemical sensor for the determination of free glutamate in food samples was fabricated based on the
    immobilization of 0.1 M copper(II) nitrate trihydrate onto sol-gel glass powder which was then mixed with methyl cellulose
    to form a pellet. A distinctive colour change from light blue to dark blue was observed in the presence of glutamate in
    less than 1 min. The colour change was measured by reflectance spectrophotometer at 691 nm. A linear relationship
    between the reflectance intensity and glutamate concentration was observed in the range of 12.5 to 500 mM with a limit
    of detection of 10.6 mM. This method is also reproducible with a relative standard deviation of less than 5%, no effect on
    pH of the glutamate solution and a good recovery of above 80%. The sensor was used for the determination of glutamate
    in common food items such as soups and flavor enhancers. The results obtained from the fabricated sensor were found
    to be comparable with HPLC method.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Tahir AM, Chowdhury MEH, Khandakar A, Al-Hamouz S, Abdalla M, Awadallah S, et al.
    Sensors (Basel), 2020 Feb 11;20(4).
    PMID: 32053914 DOI: 10.3390/s20040957
    Gait analysis is a systematic study of human locomotion, which can be utilized in variousapplications, such as rehabilitation, clinical diagnostics and sports activities. The various limitationssuch as cost, non-portability, long setup time, post-processing time etc., of the current gait analysistechniques have made them unfeasible for individual use. This led to an increase in research interestin developing smart insoles where wearable sensors can be employed to detect vertical groundreaction forces (vGRF) and other gait variables. Smart insoles are flexible, portable and comfortablefor gait analysis, and can monitor plantar pressure frequently through embedded sensors thatconvert the applied pressure to an electrical signal that can be displayed and analyzed further.Several research teams are still working to improve the insoles' features such as size, sensitivity ofinsoles sensors, durability, and the intelligence of insoles to monitor and control subjects' gait bydetecting various complications providing recommendation to enhance walking performance. Eventhough systematic sensor calibration approaches have been followed by different teams to calibrateinsoles' sensor, expensive calibration devices were used for calibration such as universal testingmachines or infrared motion capture cameras equipped in motion analysis labs. This paper providesa systematic design and characterization procedure for three different pressure sensors: forcesensitiveresistors (FSRs), ceramic piezoelectric sensors, and flexible piezoelectric sensors that canbe used for detecting vGRF using a smart insole. A simple calibration method based on a load cellis presented as an alternative to the expensive calibration techniques. In addition, to evaluate theperformance of the different sensors as a component for the smart insole, the acquired vGRF fromdifferent insoles were used to compare them. The results showed that the FSR is the most effectivesensor among the three sensors for smart insole applications, whereas the piezoelectric sensors canbe utilized in detecting the start and end of the gait cycle. This study will be useful for any researchgroup in replicating the design of a customized smart insole for gait analysis.
    Matched MeSH terms: Pressure
  19. Kumbhar SA, Kokare CR, Shrivastava B, Gorain B
    Ann Pharm Fr, 2020 May 06.
    PMID: 32387177 DOI: 10.1016/j.pharma.2020.04.005
    A novel, simple reversed-phase high-performance liquid chromatographic (RP-HPLC) analytical method was developed and validated for the quantitative determination of asenapine from various nanoemulsion components during pre-formulation screening. The developed method was validated according to ICH Q2 (R1) guidelines. The developed and validated method was precisely and accurately quantified asenapine in various oils, surfactants and co-surfactants. The separation of asenapine was carried out on Hypersil BDS C18, 250×4.6mm, 5μm particle size column using methanol: acetonitrile (90:10) as mobile phase with a flow rate of 1mL.min-1. Measurement at 270nm for the concentration range of 5 to 50μg.mL-1 of the analyte was found to be linear with the determination coefficient (r2) of 0.999 as calculated by the least square regression method. The validated method was sensitive with LOD of 10.0ng.mL-1 and LOQ of 30.0ng.mL-1. Further, the method was precise and accurate, where the intraday and interday precision values were ranged from 0.70-0.95 and 0.36-0.95, respectively with the corresponding accuracy were ranged from 98.80-100.63 and 98.36-100.63. This developed and validated RP-HPLC method for asenapine was applied in the quantitative determination and screening of various oils, surfactants, and co-surfactants during the development of the asenapine maleate nanoemulsion.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  20. Abd Samat NMA, Ahmad S, Awang Y, Bakar RAH, Hakiman M
    Molecules, 2020 Jun 19;25(12).
    PMID: 32575450 DOI: 10.3390/molecules25122833
    Sabah snake grass or Clinacanthus nutans has drawn public interest having significant economic benefits attributable to the presence of phytochemicals and several interesting bioactive constituents that may differ according to harvesting age and harvesting frequency. The current study was aimed to evaluate the effect of harvesting age and harvesting frequency towards herbal yield, antioxidant activities, phytochemicals synthesis, and bioactive compounds of C. nutans. A factorial randomized completely block design with five replications was used to illustrate the relationship between herbal yield, DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) assays, total phenolic and flavonoid content affected by harvesting age (week 8, 12, and 16 after transplanting), and harvesting frequency (harvest 1, 2, and 3). The bioactive compounds by HPLC were also determined to describe the interaction effect between both harvesting age and harvesting frequency. The yield, antioxidant activities, and phytochemical contents were gradually increased as the plant grew, with the highest recorded during week 16. However, the synthesis and activities of phytochemicals were reduced in subsequent harvests despite the increment of the herbal yield. All bioactive compounds were found to be influenced insignificantly and significantly by harvesting age and harvesting frequency, respectively, specifically to shaftoside, iso-orientin, and orientin. Among all constituents, shaftoside was the main compound at various harvesting ages and harvesting frequencies. These results indicated that harvesting at week 16 with 1st harvest frequency might enhance the yield while sustaining the high synthesis of polyphenols and antioxidant activities of C. nutans.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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