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Molecular and physiological responses during thermal acclimation of leaf photosynthesis and respiration in rice

Rashid FAA, Crisp PA, Zhang Y, Berkowitz O, Pogson BJ, Day DA, et al.

Plant Cell Environ, 2020 03;43(3):594-610.
PMID: 31860752 DOI: 10.1111/pce.13706

To further our understanding of how sustained changes in temperature affect the carbon economy of rice (Oryza sativa), hydroponically grown plants of the IR64 cultivar were developed at 30°C/25°C (day/night) before being shifted to 25/20°C or 40/35°C. Leaf messenger RNA and protein abundance, sugar and starch concentrations, and gas-exchange and elongation rates were measured on preexisting leaves (PE) already developed at 30/25°C or leaves newly developed (ND) subsequent to temperature transfer. Following a shift in growth temperature, there was a transient adjustment in metabolic gene transcript abundance of PE leaves before homoeostasis was reached within 24 hr, aligning with Rdark (leaf dark respiratory CO2 release) and An (net CO2 assimilation) changes. With longer exposure, the central respiratory protein cytochrome c oxidase (COX) declined in abundance at 40/35°C. In contrast to Rdark , An was maintained across the three growth temperatures in ND leaves. Soluble sugars did not differ significantly with growth temperature, and growth was fastest with extended exposure at 40/35°C. The results highlight that acclimation of photosynthesis and respiration is asynchronous in rice, with heat-acclimated plants exhibiting a striking ability to maintain net carbon gain and growth when exposed to heat-wave temperatures, even while reducing investment in energy-conserving respiratory pathways.

Matched MeSH terms: Hot Temperature; Temperature
Effect of rice bran oil addition on the oxidative degradation and fatty acid composition of soybean oil during heating

Ali MA, Islam MA, Othman NH, Noor AM, Ibrahim M

Acta Sci Pol Technol Aliment, 2020 1 14;18(4):427-438.
PMID: 31930793 DOI: 10.17306/J.AFS.0694

BACKGROUND: Rice bran oil (RBO) contains significant amounts of micronutrients (oryzanol, tocotrienol, tocopherol, phytosterols etc.) that impart a high resistance to thermal oxidation of the oil. The high oxidative stability of RBO can make it a preferred oil to improve the oxidative and flavor stabilities of other oils rich in PUFAs. In this study, the changes in the oxidative status and fatty acid composition in soybean oil (SO) blended with RBO under extreme thermal conditions were evaluated.
METHODS: The blends were prepared in a volume ratio of 10:90, 20:80, 40:60, and 60:40 (RBO:SO). The changes in the oxidative parameters and fatty acid composition of the samples during heating at frying temperature (170°C) were determined using analytical and instrumental methods. Oxidative alteration was also monitored by recording FTIR spectra of oil samples.
RESULTS: The increase in oxidative parameters (free fatty acid, color, specific extinctions, peroxide value, p-anisidine value, and thiobarbituric acid value) was greater in pure SO as compared to RBO or blend oils during heating. This indicates that the SO samples incorporated with RBO have the least degradation, while pure SO has the highest. Blending resulted in a lower level of polyunsaturated fatty acids (PUFA) with a higher level of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). During heating, the relative content of PUFA decreased and that of SFA increased. However, the presence of RBO in SO slowed down the oxidative deterioration of PUFA. In FTIR, the peak intensities in SO were markedly changed in comparison with blend oils during heating. The reduction in the formation of oxidative products in SO during thermal treatment increased as the concentration of the RBO in SO increased; however, the levels of the protective effect of RBO did not increase steadily with an increase in its concentration.
CONCLUSIONS: During thermal treatment, the generation of hydroperoxides, their degradation and formation of secondary oxidative products as evaluated by oxidative indices, fatty acids and IR absorbances were lower in blend oils compared to pure SO. In conclusion, RBO can significantly retard the process of lipid peroxidation in SO during heating at frying temperature.

Matched MeSH terms: Hot Temperature*
Fulltext Retention of Carotenes and Vitamin E, and Physico-chemical Changes Occurring upon Heating Red Palm Olein Using Deep-fat Fryer, Microwave Oven and Conventional Oven

Loganathan R, Tarmizi AHA, Vethakkan SR, Teng KT

J Oleo Sci, 2020 Mar 01;69(3):167-183.
PMID: 32051355 DOI: 10.5650/jos.ess19209

Red palm olein is known to be high in carotenes and vitamin E (tocols) and possess various nutritional benefits. This study evaluates the effect of prolonged heating using three common cooking techniques i.e. deep-fat fryer, microwave oven and conventional oven, on the profiles of carotenes and tocols as well as the physico-chemical changes occurring in red palm olein when compared to conventional palm olein. Physico-chemical changes in all oils were gauged based on their peroxide, p-anisidine and total oxidation values, acidity, and fatty acid composition. Both red palm olein and palm olein were thermally stable based on their lower rate of hydrolytic and oxidative degradations as well as higher tocols retention, which allow the oils to undergo heating up to 3 hours using deep-fat fryer and conventional oven. Nevertheless, red palm olein seemed not suitable for prolonged heating processes considering lower retention of carotenes. Microwave heating also influenced the stability of phytonutrients.

Matched MeSH terms: Hot Temperature*
Thermal death kinetics of Mediterranean, Malaysian, melon, and oriental fruit fly (Diptera: Tephritidae) eggs and third instars

Armstrong JW, Tang J, Wang S

J Econ Entomol, 2009 Apr;102(2):522-32.
PMID: 19449631

The late-aged egg and third-instar life stages of laboratory-reared Malaysian fruit fly, Bactrocera latifrons (Hendel); Mediterranean fruit fly, Ceratitis capitata (Wiedemann); melon fly, B. cucurbitae Coquillett; and oriental fruit fly, B. dorsalis (Hendel), (Diptera: Tephritidae); and the third instars of wild Mediterranean fruit fly were exposed to thermal treatments. A heating block system was used to determine the thermal death kinetics of the four fruit fly species. Treatments consisted of heating the fruit fly life stages to 44, 46, 48, and 50 degrees C and holding for different times ranging from 0 to 120 min depending on the thermal mortality response and time required to obtain 100% mortality for each species and life stage. The 0.5-order kinetic model had the best fit to the survival ratio for all the treatment temperatures and was used to predict lethal times. The thermal death time (TDT) curves showed a tolerance order of Mediterranean fruit fly eggs < or = third instars at 44, 46, and 50 degrees C, third instars < or = eggs at 48 degrees C, and wild third instars < the laboratory-reared third instars. Comparison between Mediterranean fruit fly third instar thermotolerance from Hawaii and Israel showed that Israel Mediterranean fruit fly was more thermotolerant. A comparison of minimum treatment times at a given temperature required to obtain 100% mortality of laboratory-reared Malaysian, Mediterranean (Hawaii and Israel strains), melon, Mexican, and oriental fruit fly eggs or third instars and wild Mediterranean fruit fly (Hawaii strain) eggs or third instars showed that oriental fruit fly was the most thermotolerant among the third instars, and the difference in heat tolerance between third instars and eggs was negligible at 50 degrees C.

Matched MeSH terms: Hot Temperature*
Effects of inlet temperature and carrier concentration on spray-dried 'cempedak' (Artocarpus integer) fruit powder and its reconstitution properties

Pui LP, Karim R, Yusof YA, Wong CW, Ghazali HM

Acta Sci Pol Technol Aliment, 2021 4 23;20(2):135-148.
PMID: 33884852 DOI: 10.17306/J.AFS.0801

BACKGROUND: 'Cempedak' (Artocarpus integer) is an aromatic fruit which is similar to jackfruit. Although it is rich in vitamin A and is consumed fresh, the fruit has a short shelf life. Hence, it can be converted through a spray-drying process, to form powder, which is more stable. Powder flow properties are important when considering storage, while its reconstitution characteristics are critical for the consumer to make juice from the product.
METHODS: The parameters of spray-dried 'cempedak' fruit powder under study include inlet air temperature (140-180°C) and maltodextrin (DE 10) concentrations (5-15% w/w). Response surface methodology involving 14 runs was used to assess the effects of inlet temperature and maltodextrin on the powder flow properties and reconstitution properties of the spray-dried 'cempedak' powder.
RESULTS: Out of the tested responses, only bulk density, change in cake height ratio, and water solubility index had a high coefficient of determination value. Inlet air temperature was found to be the main parameter to affect the bulk density, caking and water solubility index, when compared to maltodextrin concentration. By setting minimization of caking and maximization of water solubility index as the main determinants, the optimal parameters of 160°C inlet temperature and 15% (w/w) maltodextrin DE10 were generated, with a desirability of 0.697.
CONCLUSIONS: The powder produced under optimal conditions (160°C and 15% w/w maltodextrin) had a low bulk density (480.01 kg/m3), low caking properties (0.17 change in cake height ratio), and a high solubility index (88.69). This indicates that the powder is stable to be stored (without caking) and will have good reconstitution when added to water.

Matched MeSH terms: Temperature*
A rapid micro quantification method of paracetamol in suppositories using differential scanning calorimetry

Noordin MI, Chung LY

Drug Dev Ind Pharm, 2004;30(9):925-30.
PMID: 15554216

This study adopts Differential Scanning Calorimetry (DSC) to analyze the thermal properties of samples (2.5-4.0 mg) from the tip, middle, and base sections of individual paracetamol suppositories, which were sampled carefully using a stainless steel scalpel. The contents of paracetamol present in the samples obtained from these sections were determined from the enthalpies of fusion of paracetamol and expressed as % w/w paracetamol to allow comparison of the amount of paracetamol found in each section. The tip, middle, and base sections contained 10.1+/-0.2%, 10.1+/-0.2%, and 10.3+/-0.2% w/w paracetamol, and are statistically similar (One-way anova; p>0.05). This indicates that the preparation technique adopted produces high quality suppositories in terms of content uniformity. The contents of paracetamol in the 120-mg paracetamol suppositories determined by DSC and UV spectrophotometry were statistically equivalent (Students's t-test; p>0.05), 120.8+/-2.6 mg and 120.8+/-1.5 mg, respectively, making DSC a clear alternative method for the measurement of content of drug in suppositories. The main advantages of the method are that samples of only 2.5-4.0 mg are required and the procedure does not require an extraction process, which allows for the analysis to be completed rapidly. In addition, it is highly sensitive and reproducible, with the lower detection limit at 4.0% w/w paracetamol, which is about 2.5 times lower than the content of paracetamol (10% w/w) present in our 120-mg paracetamol suppositories and commercial paracetamol suppositories, which contained about 125 mg paracetamol. Therefore, this method is particularly suited for determination of content uniformity in individual suppositories in quality control (QC) and in process quality control (PQC).

Matched MeSH terms: Temperature; Transition Temperature
Fulltext Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage

Silakhori M, Naghavi MS, Metselaar HSC, Mahlia TMI, Fauzi H, Mehrali M

Materials (Basel), 2013 Apr 29;6(5):1608-1620.
PMID: 28809232 DOI: 10.3390/ma6051608

Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.

Matched MeSH terms: Hot Temperature; Temperature
Fulltext Morphological Change of Heat Treated Bovine Bone: A Comparative Study

Pramanik S, Hanif ASM, Pingguan-Murphy B, Abu Osman NA

Materials (Basel), 2012 Dec 21;6(1):65-75.
PMID: 28809294 DOI: 10.3390/ma6010065

In this work, untreated bovine cortical bones (BCBs) were exposed to a range of heat treatments in order to determine at which temperature the apatite develops an optimum morphology comprising porous nano hydroxyapatite (nanoHAp) crystals. Rectangular specimens (10 mm × 10 mm × 3-5 mm) of BCB were prepared, being excised in normal to longitudinal and transverse directions. Specimens were sintered at up to 900 °C under ambient pressure in order to produce apatites by two steps sintering. The samples were characterized by thermogravimetric analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM) attached to an energy-dispersive X-ray spectroscopy detector. For the first time, morphology of the HAp particles was predicted by XRD, and it was verified by SEM. The results show that an equiaxed polycrystalline HAp particle with uniform porosity was produced at 900 °C. It indicates that a porous nanoHAp achieved by sintering at 900 °C can be an ideal candidate as an in situ scaffold for load-bearing tissue applications.

Matched MeSH terms: Hot Temperature; Temperature
Effect of Type of Protein-Based Microcapsules and Storage at Various Ambient Temperatures on the Survival and Heat Tolerance of Spray Dried Lactobacillus acidophilus

Dianawati D, Lim SF, Ooi YBH, Shah NP

J Food Sci, 2017 Sep;82(9):2134-2141.
PMID: 28843042 DOI: 10.1111/1750-3841.13820

The aims of this study were to evaluate the effect of types of protein-based microcapsules and storage at various ambient temperatures on the survival of Lactobacillus acidophilus during exposure to simulated gastrointestinal tract and on the change in thermo-tolerance during heating treatment. The encapsulating materials were prepared using emulsions of protein (sodium caseinate, soy protein isolate, or pea protein), vegetable oil, and glucose, with maltodextrin was used as a wall material. The formulations were heated at 90 °C for 30 min to develop Maillard substances prior to being incorporated with L. acidophilus. The mixtures were then spray dried. The microspheres were stored at 25, 30, and 35 °C for 8 wk and examined every 4 wk. The addition of proteins as encapsulating materials demonstrated a significant protective effect (P < 0.05) as compared to the control sample. Sodium caseinate and soy protein isolate appeared more effective than pea protein in protecting the bacteria after spray drying and during the storage at different room temperatures. Storage at 35 °C resulted in a significant decrease in survival at end of storage period regardless the type of encapsulating materials. The addition of protein-based materials also enhanced the survival of L. acidophilus during exposure to simulated gastrointestinal condition as compared to the control. After spray drying and after 0th wk storage, casein, soy protein isolate, and pea protein-based formulations protected the bacteria during heat treatment. In fact, a significant decrease in thermal tolerance was inevitable after 2 wk of storage at 25 °C.

Matched MeSH terms: Hot Temperature; Temperature
Fulltext RNA-seq assembly and analysis of Garcinia mangostana transcriptome during seed germination

Azlan NDK, Isa MNM, Zainal Z

Data Brief, 2017 Oct;14:548-550.
PMID: 28861452 DOI: 10.1016/j.dib.2017.07.064

Garcinia mangostana is a tropical fruit plant rich in antioxidant and bears recalcitrant seeds. The extent of water loss and low temperature tolerable by recalcitrant seed varies from regular orthodox seeds. Present study generates transcriptome resources for G. mangostana to postulate potential transcriptome differences between recalcitrant and orthodox seeds during seed germination process. Raw reads of pooled samples used for the assembly have been deposited in genbank accession SRR5412332.

Matched MeSH terms: Cold Temperature; Temperature
The Effects and Action Mechanisms of Phytoestrogens on Vasomotor Symptoms During Menopausal Transition: Thermoregulatory Mechanism

Hairi HA, Shuid AN, Ibrahim N', Jamal JA, Mohamed N, Mohamed IN

Curr Drug Targets, 2019;20(2):192-200.
PMID: 28814228 DOI: 10.2174/1389450118666170816123740

BACKGROUND: Phytoestrogens have recently been claimed to positively influence menopausal discomforts, including hot flashes. However, little is known about the influence of phytoestrogens on core body temperature during oestrogen fluctuation at menopause.
OBJECTIVE: Previously published findings showed that phytoestrogens could relieve menopausal complaints, thus, the present review was aimed at assessing the effects of phytoestrogens on thermoregulatory mechanism during menopausal transition.
RESULTS: The molecular mechanisms underlying hot flashes are complex. Oestrogen fluctuations cause hypothalamic thermoregulatory centre dysfunction, which leads to hot flashes during menopause. The phytoestrogens of interest, in relation to human health, include isoflavones, lignans, coumestans, and stilbenes, which are widely distributed in nature. The phytoestrogens are capable of reducing hot flashes via their oestrogen-like hormone actions. The potential effects of phytoestrogens on hot flashes and their molecular mechanisms of action on thermoregulatory centre are discussed in this review.
CONCLUSION: The effects of phytoestrogens on these mechanisms may help explain their beneficial effects in alleviating hot flashes and other menopausal discomforts.

Matched MeSH terms: Body Temperature Regulation/drug effects
Fulltext An Evidence-Based Review of Impacts, Strategies and Tools to Mitigate Urban Heat Islands

Leal Filho W, Echevarria Icaza L, Emanche VO, Quasem Al-Amin A

Int J Environ Res Public Health, 2017 12 19;14(12).
PMID: 29257100 DOI: 10.3390/ijerph14121600

The impacts of climate changes on cities, which are home to over half of the world's population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in maintaining quality of life. Among the negative consequences of rapid city growth is the expansion of the problems posed by urban heat islands (UHIs), defined as areas in a city that are much warmer than other sites, especially in comparison with rural areas. This paper analyses the consistency of the UHI-related literature in three stages: first it outlines its characteristics and impacts in a wide variety of cities around the world, which poses pressures to public health in many different countries. Then it introduces strategies which may be employed in order to reduce its effects, and finally it analyses available tools to systematize the initial high level assessment of the phenomenon for multidisciplinary teams involved in the urban planning process. The analysis of literature on the characteristics, impacts, strategies and digital tools to assess on the UHI, reveals the wide variety of parameters, methods, tools and strategies analysed and suggested in the different studies, which does not always allow to compare or standardize the diagnosis or solutions.

Matched MeSH terms: Hot Temperature/adverse effects*
A penalized quantitative structure-property relationship study on melting point of energetic carbocyclic nitroaromatic compounds using adaptive bridge penalty

Al-Fakih AM, Algamal ZY, Lee MH, Aziz M

SAR QSAR Environ Res, 2018 May;29(5):339-353.
PMID: 29493376 DOI: 10.1080/1062936X.2018.1439531

A penalized quantitative structure-property relationship (QSPR) model with adaptive bridge penalty for predicting the melting points of 92 energetic carbocyclic nitroaromatic compounds is proposed. To ensure the consistency of the descriptor selection of the proposed penalized adaptive bridge (PBridge), we proposed a ridge estimator ([Formula: see text]) as an initial weight in the adaptive bridge penalty. The Bayesian information criterion was applied to ensure the accurate selection of the tuning parameter ([Formula: see text]). The PBridge based model was internally and externally validated based on [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], the Y-randomization test, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and the applicability domain. The validation results indicate that the model is robust and not due to chance correlation. The descriptor selection and prediction performance of PBridge for the training dataset outperforms the other methods used. PBridge shows the highest [Formula: see text] of 0.959, [Formula: see text] of 0.953, [Formula: see text] of 0.949 and [Formula: see text] of 0.959, and the lowest [Formula: see text] and [Formula: see text]. For the test dataset, PBridge shows a higher [Formula: see text] of 0.945 and [Formula: see text] of 0.948, and a lower [Formula: see text] and [Formula: see text], indicating its better prediction performance. The results clearly reveal that the proposed PBridge is useful for constructing reliable and robust QSPRs for predicting melting points prior to synthesizing new organic compounds.

Matched MeSH terms: Transition Temperature*
Physical properties and stability evaluation of fish oil-in-water emulsions stabilized using thiol-modified β-lactoglobulin fibrils-chitosan complex

Chang HW, Tan TB, Tan PY, Abas F, Lai OM, Wang Y, et al.

Food Res Int, 2018 03;105:482-491.
PMID: 29433239 DOI: 10.1016/j.foodres.2017.11.034

Fish oil-in-water emulsions containing fish oil, thiol-modified β-lactoglobulin (β-LG) fibrils, chitosan and maltodextrin were fabricated using a high-energy method. The results showed that chitosan coating induced charge reversal; denoting successful biopolymers complexation. A significantly (p<0.05) larger droplet size and lower polydispersity index value, attributed to the thicker chitosan coating at the oil-water interface, were observed. At high chitosan concentrations, the cationic nature of chitosan strengthened the electrostatic repulsion between the droplets, thus conferring high oxidative stability and low turbidity loss rate to the emulsions. The apparent viscosity of emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex was higher than those stabilized using β-LG fibrils alone, resulting in the former's higher creaming stability. Under thermal treatments (63°C and 100°C), emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex possessed higher heat stability as indicated by the consistent droplet sizes observed. Chitosan provided a thicker protective layer that protected the oil droplets against high temperature. Bridging flocculation occurred at low chitosan concentration (0.1%, w/w), as revealed through microscopic observations which indicated the presence of large flocs. All in all, this work provided us with a better understanding of the application of protein fibrils-polysaccharide complex to produce stable emulsion.

Matched MeSH terms: Hot Temperature; Temperature
Thermomechanical damage in cortical bone caused by margins of surgical drill bit: A finite element analysis

Akhbar MFA

Comput Methods Programs Biomed, 2023 Apr;231:107361.
PMID: 36736133 DOI: 10.1016/j.cmpb.2023.107361

BACKGROUND AND OBJECTIVE: Conventional surgical drill bits suffer from several drawbacks, including extreme heat generation, breakage, jam, and undesired breakthrough. Understanding the impacts of drill margin on bone damage can provide insights that lay the foundation for improvement in the existing surgical drill bit. However, research on drill margins in bone drilling is lacking. This work assesses the influences of margin height and width on thermomechanical damage in bone drilling.
METHODS: Thermomechanical damage-maximum bone temperature, osteonecrosis diameter, osteonecrosis depth, maximum thrust force, and torque-were calculated using the finite element method under various margin heights (0.05-0.25 mm) and widths (0.02-0.26 mm). The simulation results were validated with experimental tests and previous research data.
RESULTS: The effect of margin height in increasing the maximum bone temperature, osteonecrosis diameter, and depth were at least 19.1%, 41.9%, and 59.6%, respectively. The thrust force and torque are highly sensitive to margin height. A higher margin height (0.21-0.25 mm) reduced the thrust force by 54.0% but increased drilling torque by 142.2%. The bone temperature, osteonecrosis diameter, and depth were 16.5%, 56.5%, and 81.4% lower, respectively, with increasing margin width. The minimum thrust force (11.1 N) and torque (41.9 Nmm) were produced with the highest margin width (0.26 mm). The margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 produced the highest sum of weightage.
CONCLUSIONS: A surgical drill bit with a margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 mm can produce minimum thermomechanical damage in cortical bone drilling. The insights regarding the suitable ranges for margin height and width from this study could be adopted in future research devoted to optimizing the margin of the existing surgical drill bit.

Matched MeSH terms: Hot Temperature; Temperature
Effects of production conditions on yield and physicochemical properties of biochars produced from rice husk and oil palm empty fruit bunches

Yavari S, Malakahmad A, Sapari NB

Environ Sci Pollut Res Int, 2016 Sep;23(18):17928-40.
PMID: 27255313 DOI: 10.1007/s11356-016-6943-3

Biochar is the bio-solid material produced by pyrolysis. The biochar properties are controlled by feedstock and pyrolysis variables. In this study, the impacts of these production variables on biochar yield and physicochemical properties including pH, cation exchange capacity (CEC), total organic carbon (TOC) content, surface area, and pore volume and size were investigated. Rice husk (RH) and oil palm empty fruit bunches (EFB) were used as biomass. The biochars were produced at temperature range of 300 to 700 °C, heating rate of 3 to 10 °C/min and retention time of 1 to 3 h. The pyrolysis conditions were optimized using response surface methodology (RSM) technique to maximize the values of the responses. Analysis of variance (ANOVA) of the results demonstrated that the data fitted well to the linear and quadratic equations. Temperature was found to be the most effective parameter on the responses followed by retention time and heating rate, sequentially. CEC, TOC, surface area, and pore characteristics were evaluated as biochar properties determining their sorption potential. The optimum conditions for the maximum values of the properties were temperatures of 700 and 493.44 °C and time of 3 and 1 h for RH and EFB biochars, respectively. Heating rate at 3 °C/min was found to be the best rate for both biochars. The structure of EFB biomass was more sensitive to heating than rice husk. The biomass type and the production variables were demonstrated as the direct effective factors on biochar yield and physicochemical properties.

Matched MeSH terms: Hot Temperature; Temperature
Fulltext Impact of two-phase hybrid nanofluid approach on mixed convection inside wavy lid-driven cavity having localized solid block

Alsabery AI, Tayebi T, Kadhim HT, Ghalambaz M, Hashim I, Chamkha AJ

J Adv Res, 2021 May;30:63-74.
PMID: 34026287 DOI: 10.1016/j.jare.2020.09.008

Introduction: Mixed convection flow and heat transfer within various cavities including lid-driven walls has many engineering applications. Investigation of such a problem is important in enhancing the performance of the cooling of electric, electronic and nuclear devices and controlling the fluid flow and heat exchange of the solar thermal operations and thermal storage.
Objectives: The main aim of this fundamental investigation is to examine the influence of a two-phase hybrid nanofluid approach on mixed convection characteristics including the consequences of varying Richardson number, number of oscillations, nanoparticle volume fraction, and dimensionless length and dimensionless position of the solid obstacle.
Methods: The migration of composite hybrid nanoparticles due to the nano-scale forces of the Brownian motion and thermophoresis was taken into account. There is an inner block near the middle of the enclosure, which contributes toward the flow, heat, and mass transfer. The top lid cover wall of the enclosure is allowed to move which induces a mixed convection flow. The impact of the migration of hybrid nanoparticles with regard to heat transfer is also conveyed in the conservation of energy. The governing equations are molded into the non-dimensional pattern and then explained using the finite element technique. The effect of various non-dimensional parameters such as the volume fraction of nanoparticles, the wave number of walls, and the Richardson number on the heat transfer and the concentration distribution of nanoparticles are examined. Various case studies for Al2O3-Cu/water hybrid nanofluids are performed.
Results: The results reveal that the temperature gradient could induce a notable concentration variation in the enclosure.
Conclusion: The location of the solid block and undulation of surfaces are valuable in the control of the heat transfer and the concentration distribution of the composite nanoparticles.

Matched MeSH terms: Hot Temperature; Temperature
Fulltext Astronomically calibrated 40Ar/39Ar age for the Toba supereruption and global synchronization of late Quaternary records

Storey M, Roberts RG, Saidin M

Proc Natl Acad Sci U S A, 2012 Nov 13;109(46):18684-8.
PMID: 23112159 DOI: 10.1073/pnas.1208178109

The Toba supereruption in Sumatra, ∼74 thousand years (ka) ago, was the largest terrestrial volcanic event of the Quaternary. Ash and sulfate aerosols were deposited in both hemispheres, forming a time-marker horizon that can be used to synchronize late Quaternary records globally. A precise numerical age for this event has proved elusive, with dating uncertainties larger than the millennial-scale climate cycles that characterized this period. We report an astronomically calibrated (40)Ar/(39)Ar age of 73.88 ± 0.32 ka (1σ, full external errors) for sanidine crystals extracted from Toba deposits in the Lenggong Valley, Malaysia, 350 km from the eruption source and 6 km from an archaeological site with stone artifacts buried by ash. If these artifacts were made by Homo sapiens, as has been suggested, then our age indicates that modern humans had reached Southeast Asia by ∼74 ka ago. Our (40)Ar/(39)Ar age is an order-of-magnitude more precise than previous estimates, resolving the timing of the eruption to the middle of the cold interval between Dansgaard-Oeschger events 20 and 19, when a peak in sulfate concentration occurred as registered by Greenland ice cores. This peak is followed by a ∼10 °C drop in the Greenland surface temperature over ∼150 y, revealing the possible climatic impact of the eruption. Our (40)Ar/(39)Ar age also provides a high-precision calibration point for other ice, marine, and terrestrial archives containing Toba sulfates and ash, facilitating their global synchronization at unprecedented resolution for a critical period in Earth and human history beyond the range of (14)C dating.

Matched MeSH terms: Cold Temperature; Temperature
Fulltext Heat literacy and adaptation among semi-rural community in Malaysia

Nellis S, Thu M, Ismail MR, Barteit S, Gouwanda D, Bärnighausen T, et al.

Lancet Planet Health, 2024 Apr;8 Suppl 1:S8.
PMID: 38632923 DOI: 10.1016/S2542-5196(24)00073-1

BACKGROUND: Heatwaves present health risks globally but there is limited evidence on how temperature perceptions affect activities. This study aimed to examine community perceptions of heat as a potential health hazard and ascertain the current heat protection measures of the residents of the South East Asia Community Observatory (SEACO) in Malaysia.
METHODS: In this longitudinal study, we randomly selected community members aged between 18 and 70 years who resided in Segamat district of Johor state, Malaysia. Over 21 days, we conducted three home visits to each participant. During each visit, participants completed a questionnaire consisting of Likert scale, multiple choice, and free text questions and we collected quantitative and qualitative data. These inquiries assessed the participants' perception of heat as health threat, whether or not they took heat preventive measures, and the specific protective measures they routinely employed. Descriptive data analyses were conducted and patterns of protective measures were investigated.
FINDINGS: Between March 29 and July 31, 2023, 120 participants (72 women and 48 men) completed 360 questionnaires over three home visits. Initially, 58% participants recognised heat hazards to daily activities, decreasing to 42% and 35% by visits 2 and 3. Participants took preventive measures throughout the day, which was consistently high between 1200 h and 1400 h, with 77% of participants taking preventive measures on visit 1, 82% on visit 2, and 82% on visit 3. Use of preventive measures was also high between 1400 h and 1730 h, with 77% using preventive measure on visit 1, 81% on visit 2, and 79% on visit 3. The most common protective measures were fans (used by 68-88% of participants), drinking more water (70-78% of participants), and resting (44-72% of participants). The least common were relocating to cooler places, removing clothes, and using wet towels (0-2·5%). Despite high temperatures, perceptions of heat risks decreased over time. Participants took basic protections, especially at midday, but improved literacy and affordable cooling options are needed to protect vulnerable rural populations.
INTERPRETATION: Our findings underline the need to improve heat literacy and adaptation as only half of the population assessed perceived heat as a potential health hazard and practised limited heat protective measures. Addressing climate change and health necessitates fundamental behavioural changes on the part of individuals and communities, to protect them against the adverse effects of heat.
FUNDING: Monash University Malaysia and Heidelberg Institute of Global Health, Heidelberg University.

Matched MeSH terms: Hot Temperature*
Fulltext Genome analysis of a thermophilic exopolysaccharide-producing bacterium - Geobacillus sp. WSUCF1

Wang J, Goh KM, Salem DR, Sani RK

Sci Rep, 2019 02 07;9(1):1608.
PMID: 30733471 DOI: 10.1038/s41598-018-36983-z

Geobacillus sp. WSUCF1 is a Gram-positive, spore-forming, aerobic and thermophilic bacterium, isolated from a soil sample obtained from a compost facility. Strain WSUCF1 demonstrated EPS producing capability using different sugars as the carbon source. The whole-genome analysis of WSUCF1 was performed to disclose the essential genes correlated with nucleotide sugar precursor biosynthesis, assembly of monosaccharide units, export of the polysaccharide chain, and regulation of EPS production. Both the biosynthesis pathway and export mechanism of EPS were proposed based on functional annotation. Additionally, the genome description of strain WSUCF1 suggests sophisticated systems for its adaptation under thermophilic conditions. The presence of genes associated with CRISPR-Cas system, quorum quenching lactonase, polyketide synthesis and arsenic resistance makes this strain a potential candidate for various applications in biotechnology and biomedicine. The present study indicates that strain WSUCF1 has promise as a thermophilic EPS producer for a broad range of industrial applications. To the best of our knowledge, this is the first report on genome analysis of a thermophilic Geobacillus species focusing on its EPS biosynthesis and transportation, which will likely pave the way for both enhanced yield and tailor-made EPS production by thermophilic bacteria.

Matched MeSH terms: Temperature*

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