MyMedR

Displaying publications 1 - 20 of 104 in total

Abstract:

Sort:

Energy requirements of the population in Singapore

MILLIS J

Med J Malaya, 1956 Dec;11(2):119-25.
PMID: 13417935
Matched MeSH terms: Energy Metabolism*
Physiological Responses of Exergaming Boxing in Adults: A Systematic Review and Meta-Analysis

Mohd Jai NA, Mat Rosly M, Abd Razak NA

Games Health J, 2021 Apr;10(2):73-82.
PMID: 33297818 DOI: 10.1089/g4h.2020.0078

Objective: Studies investigating the effects of exergaming in available platforms are still limited. This review aims to systematically identify available studies on physiological intensities of exergaming boxing in able-bodied adults and recategorize them based on different platforms or environments. The meta-analysis further analyzes the physiological responses during exergaming boxing into a set of pooled data for any evidence of outliers, heterogeneity, or publication bias. Materials and Methods: A systematic search was conducted by using databases from Google Scholar, PubMed, and Web of Science. Population, intervention, comparison, and outcomes (PICO) and preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were used in the study selection process for the review. Results: From the 1534 articles examined, 16 articles were included for further analyses. Results indicated that exergaming boxing exhibits a wide range of metabolic equivalent of task (MET) values and intensity, from very light to vigorous, with elements of heterogeneity and bias detected. The Xbox® Kinect boxing platform produced higher MET (mean = 5.3) compared with the Nintendo® Wii™ boxing (mean = 3.8). Conclusion: The results of this review suggest that boxing exergames can produce intensity-adequate physical activity among younger adults that are beneficial for cardiometabolic improvements, regardless of platforms used. Exergaming boxing may be employed as an effective exercise tool to increase energy expenditure and physical activity level in young adults.

Matched MeSH terms: Energy Metabolism/physiology
The exchange of water and energy between a tropical peat forest and the atmosphere: Seasonal trends and comparison against other tropical rainforests

Tang ACI, Stoy PC, Hirata R, Musin KK, Aeries EB, Wenceslaus J, et al.

Sci Total Environ, 2019 Sep 15;683:166-174.
PMID: 31132697 DOI: 10.1016/j.scitotenv.2019.05.217

Tropical rainforests control the exchange of water and energy between the land surface and the atmosphere near the equator and thus play an important role in the global climate system. Measurements of latent (LE) and sensible heat exchange (H) have not been synthesized across global tropical rainforests to date, which can help place observations from individual tropical forests in a global context. We measured LE and H for four years in a tropical peat forest ecosystem in Sarawak, Malaysian Borneo using eddy covariance, and hypothesize that the study ecosystem will exhibit less seasonal variability in turbulent fluxes than other tropical ecosystems as soil water is not expected to be limiting in a tropical forested wetland. LE and H show little variability across seasons in the study ecosystem, with LE values on the order of 11 MJ m-2 day and H on the order of 3 MJ m-2 day-1. Annual evapotranspiration (ET) did not differ among years and averaged 1579 ± 47 mm year-1. LE exceeded characteristic values from other tropical rainforest ecosystems in the FLUXNET2015 database with the exception of GF-Guy near coastal French Guyana, which averaged 8-11 MJ m-2 day-1. The Bowen ratio (Bo) in tropical rainforests in the FLUXNET2015 database either exhibited little seasonal trend, one seasonal peak, or two peaks. Volumetric water content (VWC) and VPD explained a trivial amount of the variability of LE and Bo in some of the tropical rainforests including the study ecosystem, but were strong controls in others, suggesting differences in stomatal regulation and/or the partitioning between evaporation and transpiration. Results demonstrate important differences in the seasonal patterns in water and energy exchange across different tropical rainforest ecosystems that need to be understood to quantify how ongoing changes in tropical rainforest extent will impact the global climate system.

Matched MeSH terms: Energy Metabolism*
Fulltext Maximum acceptable frequency of lift for combined manual material handling task in Malaysia

Widia M, Md Dawal SZ, Yusoff N

PLoS One, 2019;14(5):e0216918.
PMID: 31141545 DOI: 10.1371/journal.pone.0216918

BACKGROUND: Extensive studies have been carried out over the years to determine the maximum acceptable weight that a worker is capable of lifting in a given situation among Occidental populations across Europe and US. Nonetheless, studies that place emphasis on using lifting frequency as the quantifying task parameter, especially in developing countries such as Malaysia, appear to be in scarcity. Hence, this study determined the maximum acceptable frequency of lift (MAFL) for combined manual material handling (MMH) tasks amongst Malaysian males.
METHOD: Two lifting loads were considered in this study: 1 kg and 5 kg. Each subject adjusted his frequency of lifting using a psychophysical approach. The subjects were instructed to perform combined MMH task as fast as they could over a period of 45 minutes without exhausting themselves or becoming overheated. The physiological response energy expenditure was recorded during the experimental sessions. The ratings of perceived exertion (RPE) for four body parts (forearms, upper arm, lower back and entire body) were recorded after the subjects had completed the instructed task.
RESULTS: The mean frequencies of the MMH task had been 6.8 and 5.5 cycles/minute for lifting load of 1 and 5 kg, respectively, while the mean energy expenditure values were 4.16 and 5.62 kcal/min for 1 and 5 kg load, respectively. These displayed a significant difference in the Maximum Acceptable Frequency of Lift (MAFL) between the two loads, energy expenditure and RPE (p < 0.05) whereby the subjects appeared to work harder physiologically for heavier load.
CONCLUSION: It can be concluded that it is significant to assess physiological response and RPE in determining the maximum acceptable lifting frequency at varied levels of load weight. The findings retrieved in this study can aid in designing tasks that do not exceed the capacity of workers in order to minimise the risk of WRMSDs.

Matched MeSH terms: Energy Metabolism/physiology*
Ergonomic study for optimum printing workstation using factorial experiment and response surface methodology

Mohammad Iqbal, Hartomo Soewardi, Azmi Hassan, Che Hassan Che Haron

Journal of Occupational Safety and Health, 2004;1(2):42-48.
MyJurnal

This paper presents the use of factorial experiments and response surface methodology to determine the best workstation design configuration of an existing electronic industry. The aim is to find the value of physical dimensions that gives the best performance for the workstation. Four performance measures are selected; the cycle time, the metabolic energy expenditure, worker’s posture during the task and lifting limitations. The methodology used in this study consists of two parts. The first part is based on factorial experiments and handles discrete search over combinations of factor-levels for improving the initial solution. In the second part, the solution that was obtained earlier is further refined by changing the continuous factors by using response surface methodology. The result of this optimization study shows that the optimum value of physical dimensions gives a significant improvement for the performance measures of the workstation.

Matched MeSH terms: Energy Metabolism
Mitochondrial Dysfunction in Down Syndrome: From Pathology to Therapy

Tan KL, Lee HC, Cheah PS, Ling KH

Neuroscience, 2023 Feb 10;511:1-12.
PMID: 36496187 DOI: 10.1016/j.neuroscience.2022.12.003

Mitochondrial dysfunctions have been described in Down syndrome (DS) caused by either partial or full trisomy of chromosome 21 (HSA21). Mitochondria play a crucial role in various vital functions in eukaryotic cells, especially in energy production, calcium homeostasis and programmed cell death. The function of mitochondria is primarily regulated by genes encoded in the mitochondrion and nucleus. Many genes on HSA21 are involved in oxidative phosphorylation (OXPHOS) and regulation of mitochondrial functions. This review highlights the HSA21 dosage-sensitive nuclear-encoded mitochondrial genes associated with overexpression-related phenotypes seen in DS. This includes impaired mitochondrial dynamics, structural defects and dysregulated bioenergetic profiles such as OXPHOS deficiency and reduced ATP production. Various therapeutic approaches for modulating energy deficits in DS, effects and molecular mechanism of gene therapy and drugs that exert protective effects through modulation of mitochondrial function and attenuation of oxidative stress in DS cells were discussed. It is prudent that improving DS pathophysiological conditions or quality of life may be feasible by targeting something as simple as cellular mitochondrial biogenesis and function.

Matched MeSH terms: Energy Metabolism
Physical activity, fitness and the energy cost of activities: implications for obesity in children and adolescents in the tropics

Lau XC, Chong KH, Poh BK, Ismail MN

Adv. Food Nutr. Res., 2013;70:49-101.
PMID: 23722094 DOI: 10.1016/B978-0-12-416555-7.00002-3

The tropics cover a large section of the world in which both developed and developing countries are situated. Rapid socioeconomic development, modernization, urbanization, and globalization have affected both the food market and physical activity (PA), which in turn have propelled the obesity epidemic in the tropics. There is growing concern that overweight and obesity are emerging as major health problems among children and adolescents in the tropics, despite the fact that undernutrition still exists in many of these countries. Physical inactivity, a low metabolic rate, and lack of physical fitness (PF) have been linked to overweight and obesity. Moreover, PF in several tropical countries is declining, and these changes may be a threat to future health, as low PA and PF levels are important risk factors for noncommunicable chronic diseases. Previous studies have reported that the relationships among PA, PF, overweight, and obesity are inconsistent and inconclusive. There is no indication that variances in the energy cost of physical activities lead to obesity. Despite a lack of definite evidence to prove a causal relationship, there is enough certainty that physical inactivity and low fitness levels are linked to overweight and obesity. Hence, people living in tropical countries need to be encouraged to lead a healthier lifestyle by increasing their PA levels and reducing sedentary behaviors to prevent overweight or obesity.

Matched MeSH terms: Energy Metabolism*
Biomass accumulation and energy conversion efficiency in aromatic rice genotypes

Shahidullah SM, Hanafi MM, Ashrafuzzaman M, Razi Ismail M, Salam MA, Khair A

C. R. Biol., 2010 Jan;333(1):61-7.
PMID: 20176338 DOI: 10.1016/j.crvi.2009.10.002

A field experiment was conducted to evaluate photosynthetic efficiency along with different growth parameters of aromatic rice genotypes. Forty genotypes including three non-aromatic checks exhibited enormous variations for leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), grain yield, total dry matter, harvest index and photosynthetic efficiency or energy use efficiency (Emu) at panicle initiation and heading stages. Minimum LAI-value was 0.52 in Khazar at PI stage and maximum was 4.91 in Sakkor khora at heading stage. The CGR-value was in the range of 4.80-24.11 g m(-2) per day. The best yielder BR39 produced grain of 4.21 t ha(-1) and the worst yielder Khazar gave 1.42 t ha(-1). Total dry matter (TDM) yield varied from 4.04 to 12.26 t ha(-1) where genotypes proved their energy use efficiency a range between 0.58 to 1.65%. Emu showed a significant positive relation with TDM (r=0.80(**)), CGR (r=0.72(**)) and grain yield (r=0.66(**)). A negative correlation was established between TDM and harvest index and LAI and RGR. Path analysis result showed that NAR at heading stage exerted highest positive direct effect (0.70) on Emu.

Matched MeSH terms: Energy Metabolism*
Resting metabolic rate in a sample of girls in Malaysia and England

Henry CJ, Webster-Gandy JD, Koon PB, Ismail MN

Am J Hum Biol, 2005 Nov-Dec;17(6):818-20.
PMID: 16254909

This cross-sectional study of age matched (10-11 years), pre-menarcheal girls in England and Malaysia investigated the effect of ethnicity on resting metabolic rate (RMR). The children were recruited from schools in Oxford, England, and Kuala Lumpur, Malaysia, and all measurements were conducted in the schools. The Malaysian girls were shorter (143.7 +/- 6.5 cm and 140.1 +/- 5.3 cm (mean +/- SD) for the English and Malaysian girls respectively) and lighter (32.5 +/- 5.3 kg compared with 38.0 +/- 8.7 kg for the English girls) with a smaller fat mass and fat free mass (FFM) than the English girls. Energy expenditure was lower in the Malaysian girls (4555 +/- 531 kJ/day compared with 5178 +/- 688 kJ/day for the English girls). Although a difference in RMR was observed between the two groups, when corrected for body composition the difference was no longer significant. No effect of ethnicity on the relationship of FFM and RMR was shown when the data were analyzed using analysis of covariance.

Matched MeSH terms: Energy Metabolism/physiology*
Small Tropical Mammals Can Take the Heat: High Upper Limits of Thermoneutrality in a Bornean Treeshrew

Thonis A, Ceballos RM, Tuen AA, Lovegrove BG, Levesque DL

Physiol Biochem Zool, 2020 3 21;93(3):199-209.
PMID: 32196407 DOI: 10.1086/708467

Tropical ectotherms are generally believed to be more vulnerable to global heating than temperate species. Currently, however, we have insufficient knowledge of the thermoregulatory physiology of equatorial tropical mammals, particularly of small diurnal mammals, to enable similar predictions. In this study, we measured the resting metabolic rates (via oxygen consumption) of wild-caught lesser treeshrews (Tupaia minor, order Scandentia) over a range of ambient temperatures. We predicted that, similar to other treeshrews, T. minor would exhibit more flexibility in body temperature regulation and a wider thermoneutral zone compared with other small mammals because these thermoregulatory traits provide both energy and water savings at high ambient temperatures. Basal metabolic rate was on average

1.03
±
0.10

mL O2 h-1 g-1, which is within the range predicted for a 65-g mammal. We calculated the lower critical temperature of the thermoneutral zone at 31.0°C (95% confidence interval: 29.3°-32.7°C), but using metabolic rates alone, we could not determine the upper critical temperature at ambient temperatures as high as 36°C. The thermoregulatory characteristics of lesser treeshrews provide a means of saving energy and water at temperatures well in excess of their current environmental temperatures. Our research highlights the knowledge gaps in our understanding of the energetics of mammals living in high-temperature environments, specifically in the equatorial tropics, and questions the purported lack of variance in the upper critical temperatures of the thermoneutral zone in mammals, emphasizing the importance of further research in the tropics.

Matched MeSH terms: Energy Metabolism*
Fulltext Clinical Effects of Krachaidum ( Kaempferia parviflora): A Systematic Review

Saokaew S, Wilairat P, Raktanyakan P, Dilokthornsakul P, Dhippayom T, Kongkaew C, et al.

J Evid Based Complementary Altern Med, 2017 07;22(3):413-428.
PMID: 27694558 DOI: 10.1177/2156587216669628

Kaempferia parviflora (Krachaidum) is a medicinal plant in the family Zingiberaceae. Its rhizome has been used as folk medicine for many centuries. A number of pharmacological studies of Krachaidum had claimed benefits for various ailments. Therefore, this study aimed to systematically search and summarize the clinical evidences of Krachaidum in all identified indications. Of 683 records identified, 7 studies were included. From current clinical trials, Krachaidum showed positive benefits but remained inconclusive since small studies were included. Even though results found that Krachaidum significantly increased hand grip strength and enhanced sexual erotic stimuli, these were based on only 2 studies and 1 study, respectively. With regard to harmful effects, we found no adverse events reported even when Krachaidum 1.35 g/day was used. Therefore, future studies of Krachaidum are needed with regards to both safety and efficacy outcomes.

Matched MeSH terms: Energy Metabolism/drug effects
Fulltext Synchronous activity lowers the energetic cost of nest escape for sea turtle hatchlings

Rusli MU, Booth DT, Joseph J

J Exp Biol, 2016 05 15;219(Pt 10):1505-13.
PMID: 27207954 DOI: 10.1242/jeb.134742

A potential advantage of group movement in animals is increased locomotion efficiency. This implies a reduced energetic cost for individuals that occur in larger groups such as herds, flocks and schools. When chelonian hatchlings hatch in the underground nest with finite energy for their post-hatching dispersal phase, they face the challenge of minimizing energetic expenditure while escaping the nest. The term 'social facilitation' has been used to describe the combined digging effort of sea turtle hatchlings during nest escape. Given that in a normal clutch, a substantial part of the energy reserve within the residual yolk is used by hatchlings in the digging out process, a decreased cohort size may reduce the energy reserve available to cross the beach and sustain the initial swimming frenzy. This hypothesis was experimentally tested by varying cohort size in hatchling green turtles (Chelonia mydas) and measuring energy expenditure during the nest escape process using open-flow respirometry. The energetic cost of escaping through 40 cm of sand was calculated to vary between 4.4 and 28.3 kJ per individual, the cost decreasing as the number of individuals in the cohort increased. This represents 11-68% of the energy contained in a hatchling's residual yolk at hatching. The reduced energetic cost associated with large cohorts resulted from both a lower metabolic rate per individual and a shortened nest escape time. We conclude that synchronous digging activity of many hatchlings during nest escape evolved not only to facilitate rapid nest emergence but also to reduce the energetic cost to individuals.

Matched MeSH terms: Energy Metabolism/physiology*
Fulltext Gliding saves time but not energy in Malayan colugos

Byrnes G, Libby T, Lim NT, Spence AJ

J Exp Biol, 2011 Aug 15;214(Pt 16):2690-6.
PMID: 21795564 DOI: 10.1242/jeb.052993

Gliding is thought to be an economical form of locomotion. However, few data on the climbing and gliding of free-ranging gliding mammals are available. This study employed an animal-borne three-dimensional acceleration data-logging system to collect continuous data on the climbing and gliding of free-ranging Malayan colugos, Galeopterus variegatus. We combined these movement data with empirical estimates of the metabolic costs to move horizontally or vertically to test this long-standing hypothesis by determining whether the metabolic cost to climb to sufficient height to glide a given distance was less than the cost to move an equivalent distance horizontally through the canopy. On average, colugos climb a short distance to initiate glides. However, due to the high energetic cost of climbing, gliding is more energetically costly to move a given horizontal distance than would be predicted for an animal travelling the same distance through the canopy. Furthermore, because colugos spend a small fraction of their time engaged in locomotor activity, the high costs have little effect on their overall energy budget. As a result, the energetic economy hypothesis for the origins of gliding is not supported. It is likely that other ecologically relevant factors have played a greater role in the origins of gliding in colugos and other mammals.

Matched MeSH terms: Energy Metabolism/physiology*
Fulltext The implications of time on the ground on running economy: less is not always better

Lussiana T, Patoz A, Gindre C, Mourot L, Hébert-Losier K

J Exp Biol, 2019 03 18;222(Pt 6).
PMID: 30787136 DOI: 10.1242/jeb.192047

A lower duty factor (DF) reflects a greater relative contribution of leg swing versus ground contact time during the running step. Increasing time on the ground has been reported in the scientific literature to both increase and decrease the energy cost (EC) of running, with DF reported to be highly variable in runners. As increasing running speed aligns running kinematics more closely with spring-mass model behaviours and re-use of elastic energy, we compared the centre of mass (COM) displacement and EC between runners with a low (DFlow) and high (DFhigh) duty factor at typical endurance running speeds. Forty well-trained runners were divided in two groups based on their mean DF measured across a range of speeds. EC was measured from 4 min treadmill runs at 10, 12 and 14 km h-1 using indirect calorimetry. Temporal characteristics and COM displacement data of the running step were recorded from 30 s treadmill runs at 10, 12, 14, 16 and 18 km h-1 Across speeds, DFlow exhibited more symmetrical patterns between braking and propulsion phases in terms of time and vertical COM displacement than DFhigh DFhigh limited global vertical COM displacements in favour of horizontal progression during ground contact. Despite these running kinematics differences, no significant difference in EC was observed between groups. Therefore, both DF strategies seem energetically efficient at endurance running speeds.

Matched MeSH terms: Energy Metabolism/physiology*
Fulltext Do we need different predictive equations for the acute and late phases of critical illness? A prospective observational study with repeated indirect calorimetry measurements

Tah PC, Poh BK, Kee CC, Lee ZY, Hakumat-Rai VR, Mat Nor MB, et al.

Eur J Clin Nutr, 2022 Apr;76(4):527-534.
PMID: 34462560 DOI: 10.1038/s41430-021-00999-y

BACKGROUND: Predictive equations (PEs) for estimating resting energy expenditure (REE) that have been developed from acute phase data may not be applicable in the late phase and vice versa. This study aimed to assess whether separate PEs are needed for acute and late phases of critical illness and to develop and validate PE(s) based on the results of this assessment.
METHODS: Using indirect calorimetry, REE was measured at acute (≤5 days; n = 294) and late (≥6 days; n = 180) phases of intensive care unit admission. PEs were developed by multiple linear regression. A multi-fold cross-validation approach was used to validate the PEs. The best PEs were selected based on the highest coefficient of determination (R2), the lowest root mean square error (RMSE) and the lowest standard error of estimate (SEE). Two PEs developed from paired 168-patient data were compared with measured REE using mean absolute percentage difference.
RESULTS: Mean absolute percentage difference between predicted and measured REE was <20%, which is not clinically significant. Thus, a single PE was developed and validated from data of the larger sample size measured in the acute phase. The best PE for REE (kcal/day) was 891.6(Height) + 9.0(Weight) + 39.7(Minute Ventilation)-5.6(Age) - 354, with R2 = 0.442, RMSE = 348.3, SEE = 325.6 and mean absolute percentage difference with measured REE was: 15.1 ± 14.2% [acute], 15.0 ± 13.1% [late].
CONCLUSIONS: Separate PEs for acute and late phases may not be necessary. Thus, we have developed and validated a PE from acute phase data and demonstrated that it can provide optimal estimates of REE for patients in both acute and late phases.
TRIAL REGISTRATION: ClinicalTrials.gov NCT03319329.

Matched MeSH terms: Energy Metabolism*
Energy expenditure in relation to activity of lesser mouse deer (Tragulus javanicus)

Darlis, Abdullah N, Liang JB, Purwanto B, Ho YW

Comp Biochem Physiol A Mol Integr Physiol, 2001 Nov;130(4):751-7.
PMID: 11691611

Heat production (HP) of male and female mouse deer during eating, standing and sitting was determined using the open circuit respiration chamber (RC). The time taken for similar activities was also determined in an outdoor enclosure (OD). The animals were fed kangkong (Ipomoea aquatica), sweet potato (Ipomoea batatas) and rabbit pellet ad libitum. Male mouse deer consumed more dry matter (DM), organic matter (OM) and gross energy (GE) than female. The time for each activity of male and female mouse deer kept in RC and OD was similar. The average time spent in RC and OD for both male and female, respectively, for sitting (956 and 896 min/day) was significantly (P<0.01) longer than standing (463 and 520 min/day) and eating (21 and 24 min/day). Heat production for male and female mouse deer, respectively, during eating was the highest (0.44 and 0.43 kJ/kg W(0.75)/min) followed by standing (0.37 and 0.33 kJ/kgW(0.75)/min) and sitting (0.26 and 0.26 kJ/kg W(0.75)/min). The difference in HP per min during standing between male and female was significant (P<0.05). The HP for 08.00-14.00 h and 14.00-20.00 h periods were higher than 20.00-02.00 h and 02.00-08.00 h periods. The overall HP for males during 08.00-14.00 h and 14.00-20.00 h periods were significantly (P<0.05) higher (114.8 and 119.2 kJ/kg W(0.75)) than female (107.5 and 110.4 kJ/kg W(0.75)), respectively.

Matched MeSH terms: Energy Metabolism*
Fulltext Logged tropical forests have amplified and diverse ecosystem energetics

Malhi Y, Riutta T, Wearn OR, Deere NJ, Mitchell SL, Bernard H, et al.

Nature, 2022 Dec;612(7941):707-713.
PMID: 36517596 DOI: 10.1038/s41586-022-05523-1

Old-growth tropical forests are widely recognized as being immensely important for their biodiversity and high biomass1. Conversely, logged tropical forests are usually characterized as degraded ecosystems2. However, whether logging results in a degradation in ecosystem functions is less clear: shifts in the strength and resilience of key ecosystem processes in large suites of species have rarely been assessed in an ecologically integrated and quantitative framework. Here we adopt an ecosystem energetics lens to gain new insight into the impacts of tropical forest disturbance on a key integrative aspect of ecological function: food pathways and community structure of birds and mammals. We focus on a gradient spanning old-growth and logged forests and oil palm plantations in Borneo. In logged forest there is a 2.5-fold increase in total resource consumption by both birds and mammals compared to that in old-growth forests, probably driven by greater resource accessibility and vegetation palatability. Most principal energetic pathways maintain high species diversity and redundancy, implying maintained resilience. Conversion of logged forest into oil palm plantation results in the collapse of most energetic pathways. Far from being degraded ecosystems, even heavily logged forests can be vibrant and diverse ecosystems with enhanced levels of ecological function.

Matched MeSH terms: Energy Metabolism*
Fulltext Importance of silicon and mechanisms of biosilica formation in plants

Sahebi M, Hanafi MM, Siti Nor Akmar A, Rafii MY, Azizi P, Tengoua FF, et al.

Biomed Res Int, 2015;2015:396010.
PMID: 25685787 DOI: 10.1155/2015/396010

Silicon (Si) is one of the most prevalent macroelements, performing an essential function in healing plants in response to environmental stresses. The purpose of using Si is to induce resistance to distinct stresses, diseases, and pathogens. Additionally, Si can improve the condition of soils, which contain toxic levels of heavy metals along with other chemical elements. Silicon minimizes toxicity of Fe, Al, and Mn, increases the availability of P, and enhances drought along with salt tolerance in plants through the formation of silicified tissues in plants. However, the concentration of Si depends on the plants genotype and organisms. Hence, the physiological mechanisms and metabolic activities of plants may be affected by Si application. Peptides as well as amino acids can effectively create polysilicic species through interactions with different species of silicate inside solution. The carboxylic acid and the alcohol groups of serine and asparagine tend not to engage in any significant role in polysilicates formation, but the hydroxyl group side chain can be involved in the formation of hydrogen bond with Si(OH)4. The mechanisms and trend of Si absorption are different between plant species. Furthermore, the transportation of Si requires an energy mechanism; thus, low temperatures and metabolic repressors inhibit Si transportation.

Matched MeSH terms: Energy Metabolism/physiology*
Fulltext Comparison between conventional human energy measurement and physical human energy measurement methods in wetland rice production

Elsoragaby S, Yahya A, Nawi NM, Mahadi MR, Mairghany M, Muazu A, et al.

Heliyon, 2020 Nov;6(11):e05332.
PMID: 33294651 DOI: 10.1016/j.heliyon.2020.e05332

Measurement of human energy expenditure during crop production helps in the optimization of production operations and costs by identifying steps which that can benefit from the use of appropriate mechanization technologies. This study measures human energy expenditure associated with all 6 major rice (Oryza sativa L.) cultivation operations using two measurement methods-i.e. conventional human energy expenditure method and direct measurement with a Garmin forerunner 35 body media. The aim of this study was to provide a detailed comparison of these two methods and document the human energy costs in a manner that will identify steps to be taken to help optimize agricultural practices. Results (mean + 95%CL) revealed that the total human energy expenditure obtained through the conventional method was 25.5% higher (33.3 ± 1 versus 26.6 ± 1.3) in transplanting and 26.1% higher (30.3 ± 1.9 versus 24.0 ± 2.1) than the human energy expenditure recorded using the Garmin method in broadcast seeding method. Similarly, during the harvesting operation, the conventional measurement and Garmin measurement methods differed significantly, with the conventional method the human energy expenditure was 89.9% higher (3.2 ± 0.4 versus 1.68 ± 0.2) in the fields using the transplanting and 88.7% higher (3.3 ± 0.5 versus 1.8 ± 0.3) in the fields using the broadcast seeding than the human energy expenditure recorded using the Garmin method. When using Garmin method, the human energy expenditure in the case of using the midsize combine harvester was 13.49% lesser (592.4 ± 67.2 versus 522.0 ± 75.1) than the case of using conventional one. Results based on heart rate also indicated that operations such as tillage were less intensive (72 ± 3.3 bpm) compared with operations such as chemicals spraying (135 ± 4 bpm). Although we did not have a criterion measure available to determine which method was the most accurate, the Garmin measurement gives an estimate of actual physical human energy expended in performing a specific task with consider all conditions and thus more information to aid in identifying critical operations that could be optimized and mechanized.

Matched MeSH terms: Energy Metabolism
Identification of vulnerable regions to soil loss under the dynamic saturation process

Kok K, Kim JC

Sci Total Environ, 2019 Apr 01;659:1209-1223.
PMID: 31096334 DOI: 10.1016/j.scitotenv.2018.12.398

This study presents a theoretical framework based on power law distribution to identify the vulnerable regions to soil loss in Susu river basin at Cameron Highlands, Malaysia by using the geomorphologic factors from Digital Elevation Model (DEM). Drainage area is used to describe the runoff aggregation structure of the watershed which represents the magnitude of discharge. Stream power is also used to describe the energy expenditure pattern of the watershed. They are fitted to power law distribution by means of the maximum likelihood to estimate the threshold for soil loss. The landscape stability condition is assessed through the mechanism of channel initiation. Two regions in the slope area plot are recognized as the regimes susceptible to soil loss, in that discharge, local slope and energy are sufficient for the initiation of soil movement. The result is further improved by incorporating the Topographic Wetness Index (TWI) aiming to locate vulnerable regions to soil loss under the dynamic saturation process. The final result indicates that the vulnerable regions expand from perennial reaches to ephemeral reaches as saturation process develops. It implies the transition of runoff generation from groundwater in perennial reaches to surface runoff in ephemeral reaches. Identification of soil loss vulnerable regions under the dynamic saturation process helps in planning of the mitigation measures for soil erosion.

Matched MeSH terms: Energy Metabolism

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links