Displaying publications 1 - 20 of 90 in total

  1. Sinclair BJ, Marshall KE, Sewell MA, Levesque DL, Willett CS, Slotsbo S, et al.
    Ecol. Lett., 2016 11;19(11):1372-1385.
    PMID: 27667778 DOI: 10.1111/ele.12686
    Thermal performance curves (TPCs), which quantify how an ectotherm's body temperature (Tb ) affects its performance or fitness, are often used in an attempt to predict organismal responses to climate change. Here, we examine the key - but often biologically unreasonable - assumptions underlying this approach; for example, that physiology and thermal regimes are invariant over ontogeny, space and time, and also that TPCs are independent of previously experienced Tb. We show how a critical consideration of these assumptions can lead to biologically useful hypotheses and experimental designs. For example, rather than assuming that TPCs are fixed during ontogeny, one can measure TPCs for each major life stage and incorporate these into stage-specific ecological models to reveal the life stage most likely to be vulnerable to climate change. Our overall goal is to explicitly examine the assumptions underlying the integration of TPCs with Tb , to develop a framework within which empiricists can place their work within these limitations, and to facilitate the application of thermal physiology to understanding the biological implications of climate change.
    Matched MeSH terms: Body Temperature Regulation*
  2. Mahdi RI, Gan WC, Abd Majid WH
    Sensors (Basel), 2014;14(10):19115-27.
    PMID: 25317763 DOI: 10.3390/s141019115
    Ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer 70/30 thin films are prepared by spin coating. The crystalline structure of these films is investigated by varying the annealing temperature from the ferroelectric phase to the paraelectric phase. A hot plate was used to produce a direct and an efficient annealing effect on the thin film. The dielectric, ferroelectric and pyroelectric properties of the P(VDF-TrFE) thin films are measured as a function of different annealing temperatures (80 to 140 °C). It was found that an annealing temperature of 100 °C (slightly above the Curie temperature, Tc) has induced a highly crystalline β phase with a rod-like crystal structure, as examined by X-ray. Such a crystal structure yields a high remanent polarization, Pr = 94 mC/m2, and pyroelectric constant, p = 24 μC/m2K. A higher annealing temperature exhibits an elongated needle-like crystal domain, resulting in a decrease in the crystalline structure and the functional electrical properties. This study revealed that highly crystalline P(VDF-TrFE) thin films could be induced at 100 °C by annealing the thin film with a simple and cheap method.
    Matched MeSH terms: Body Temperature
  3. Frischer R, Penhaker M, Krejcar O, Kacerovsky M, Selamat A
    Sensors (Basel), 2014;14(12):23563-23580.
    PMID: 25494352
    Precise temperature measurement is essential in a wide range of applications in the medical environment, however the regarding the problem of temperature measurement inside a simple incubator, neither a simple nor a low cost solution have been proposed yet. Given that standard temperature sensors don't satisfy the necessary expectations, the problem is not measuring temperature, but rather achieving the desired sensitivity. In response, this paper introduces a novel hardware design as well as the implementation that increases measurement sensitivity in defined temperature intervals at low cost.
    Matched MeSH terms: Body Temperature
  4. Levesque DL, Lobban KD, Lovegrove BG
    PMID: 25155185 DOI: 10.1007/s00360-014-0858-4
    Tenrecs (Order Afrosoricida) exhibit some of the lowest body temperatures (T b) of any eutherian mammal. They also have a high level of variability in both active and resting T bs and, at least in cool temperatures in captivity, frequently employ both short- and long-term torpor. The use of heterothermy by captive animals is, however, generally reduced during gestation and lactation. We present data long-term T b recordings collected from free-ranging S. setosus over the course of two reproductive seasons. In general, reproductive females had slightly higher (~32 °C) and less variable T b, whereas non-reproductive females and males showed both a higher propensity for torpor as well as lower (~30.5 °C) and more variable rest-phase T bs. Torpor expression defined using traditional means (using a threshold or cut-off T b) was much lower than predicted based on the high degree of heterothermy in captive tenrecs. However, torpor defined in this manner is likely to be underestimated in habitats where ambient temperature is close to T b. Our results caution against inferring metabolic states from T b alone and lend support to the recent call to define torpor in free-ranging animals based on mechanistic and not descriptive variables. In addition, lower variability in T b observed during gestation and lactation confirms that homeothermy is essential for reproduction in this species and probably for basoendothermic mammals in general. The relatively low costs of maintaining homeothermy in a sub-tropical environment might help shed light on how homeothermy could have evolved incrementally from an ancestral heterothermic condition.
    Matched MeSH terms: Body Temperature/physiology*; Body Temperature Regulation/physiology*
  5. Lee JY, Wakabayashi H, Wijayanto T, Hashiguchi N, Saat M, Tochihara Y
    Eur J Appl Physiol, 2011 Dec;111(12):2895-905.
    PMID: 21437607 DOI: 10.1007/s00421-011-1912-5
    For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives' homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder's law of initial value and Werner's process and controller adaptation model.
    Matched MeSH terms: Body Temperature/physiology*; Body Temperature Regulation/physiology*
  6. Iffa ED, Aziz AR, Malik AS
    Appl Opt, 2011 Feb 10;50(5):618-25.
    PMID: 21343981 DOI: 10.1364/AO.50.000618
    This paper utilizes the background oriented schlieren (BOS) technique to measure the velocity field of a variable density round jet. The density field of the jet is computed based on the light deflection created during the passage of light through the understudy jet. The deflection vector estimation was carried out using phase-based optical flow algorithms. The density field is further exploited to extract the axial and radial velocity vectors with the aid of continuity and energy equations. The experiment is conducted at six different jet-exit temperature values. Additional turbulence parameters, such as velocity variance and power spectral density of the vector field, are also computed. Finally, the measured velocity parameters are compared with the hot wire anemometer measurements and their correlation is displayed.
    Matched MeSH terms: Body Temperature
  7. Markus Bulus, Lim, Yaik-Wah, Malsiah Hamid
    Scholars have opined that the courtyard is a passive architectural design element and
    that it can act as a microclimate modifier provided that its design requirements are not
    ignored. But despite the assertions, empirical studies on the microclimatic
    performance of a fully enclosed courtyard house and the non-courtyard house seems
    to be deficient, and the assumption that the Courtyard is a passive architectural design
    element needs to be substantiated. Therefore, the purpose of this study is to
    investigate the microclimatic performance of a fully enclosed courtyard and noncourtyard
    residential buildings. The main objective is to compare their microclimatic
    performances in other to draw a conclusion on the best option. Three Hobo Weather
    Data Loggers were used to collect climatic data in the buildings, and the third one was
    situated in the outdoor area as a benchmark. The climatic variables investigated are;
    air temperature and relative humidity. The fully enclosed courtyard residential building
    is seen to have a better air temperature difference of 2 oC to 4 oC and the relative
    humidity of 2 % to 6 %. In conclusion, the fully enclosed courtyard residential building
    has confirmed a more favorable microclimatic performance, and future studies
    towards its optimization are recommended.
    Matched MeSH terms: Body Temperature
  8. Zainuddin N, Saleh H, Hashim I, Roslan R
    Sains Malaysiana, 2016;45:315-321.
    Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
    Matched MeSH terms: Body Temperature Regulation
  9. Yahaya Shagaiya Daniel, Zainal Abdul Aziz, Zuhaila Ismail, Faisal Salah
    MATEMATIKA, 2018;34(2):393-417.
    Analyzed the effects of thermal radiation, chemical reaction, heat gener-
    ation/absorption, magnetic and electric fields on unsteady flow and heat transfer of
    nanofluid. The transport equations used passively controlled. A similarity solution is
    employed to transformed the governing equations from partial differential equations to
    a set of ordinary differential equations, and then solve using Keller box method. It was
    found that the temperature is a decreasing function with the thermal stratification due to
    the fact the density of the fluid in the lower vicinity is much higher compared to the upper
    region, whereas the thermal radiation, viscous dissipation and heat generation enhanced
    the nanofluid temperature and thermal layer thickness.
    Matched MeSH terms: Body Temperature Regulation
  10. Pazikadin AR, Rifai D, Ali K, Mamat NH, Khamsah N
    Sensors (Basel), 2020 Nov 25;20(23).
    PMID: 33255797 DOI: 10.3390/s20236744
    Photovoltaic (PV) systems need measurements of incident solar irradiance and PV surface temperature for performance analysis and monitoring purposes. Ground-based network sensor measurement is preferred in many near real-time operations such as forecasting and photovoltaic (PV) performance evaluation on the ground. Hence, this study proposed a Fuzzy compensation scheme for temperature and solar irradiance wireless sensor network (WSN) measurement on stand-alone solar photovoltaic (PV) system to improve the sensor measurement. The WSN installation through an Internet of Things (IoT) platform for solar irradiance and PV surface temperature measurement was fabricated. The simulation for the solar irradiance Fuzzy Logic compensation (SIFLC) scheme and Temperature Fuzzy Logic compensation (TFLC) scheme was conducted using Matlab/Simulink. The simulation result identified that the scheme was used to compensate for the error temperature and solar irradiance sensor measurements over a variation temperature and solar irradiance range from 20 to 60 °C and from zero up to 2000 W/m2. The experimental results show that the Fuzzy Logic compensation scheme can reduce the sensor measurement error up to 17% and 20% for solar irradiance and PV temperature measurement.
    Matched MeSH terms: Body Temperature
  11. Soleimani AF, Kasim A, Alimon AR, Zulkifli I
    Pak J Biol Sci, 2008 Sep 01;11(17):2163-6.
    PMID: 19266934
    A trial was conducted to determine the influence of short-term exposure to high ambient temperature at 28 and 35 days of age on deep body temperatures (Tb) and subsequent growth of birds until 42 days of age. A total of 90 day old chicks were reared in stainless steel battery cages and were assigned at random into 18 pens of 5 birds each, with 9 pens containing males and another 9 pens containing females. Three treatment groups, each represented by 3 male and 3 female pens, were represented by T1 without any heat exposure, T2 with heat exposure starting at day 28 and T3 with heat exposure starting at day 35. Heat stress was defined as 180 min exposure to 35 +/- 1 degrees C. Tb and body weights were measured at 35, 37 and 39 days of age immediately following heat exposure. Heat stress resulted in higher Tb and Onset of heat stress at 28 days resulted in significantly lower Tb than onset of heat stress at 35 days. Lower Tb in T2 than T3 permitted recovery in body weight at 42 days. Sexes responded similarly to heat stress.
    Matched MeSH terms: Body Temperature Regulation/physiology*
  12. Bangash JI, Khan AW, Abdullah AH
    J Med Syst, 2015 Sep;39(9):91.
    PMID: 26242749 DOI: 10.1007/s10916-015-0268-5
    A significant proportion of the worldwide population is of the elderly people living with chronic diseases that result in high health-care cost. To provide continuous health monitoring with minimal health-care cost, Wireless Body Sensor Networks (WBSNs) has been recently emerged as a promising technology. Depending on nature of sensory data, WBSNs might require a high level of Quality of Service (QoS) both in terms of delay and reliability during data reporting phase. In this paper, we propose a data-centric routing for intra WBSNs that adapts the routing strategy in accordance with the nature of data, temperature rise issue of the implanted bio-medical sensors due to electromagnetic wave absorption, and high and dynamic path loss caused by postural movement of human body and in-body wireless communication. We consider the network models both with and without relay nodes in our simulations. Due to the multi-facet routing strategy, the proposed data-centric routing achieves better performance in terms of delay, reliability, temperature rise, and energy consumption when compared with other state-of-the-art.
    Matched MeSH terms: Body Temperature*
  13. Raman S, Shahla A
    Aust N Z J Obstet Gynaecol, 1992 May;32(2):117-9.
    PMID: 1520194
    A prospective study of temperature drop in 141 normal term newborn infants delivered vaginally at the labour ward, University Hospital, Kuala Lumpur were studied. The effect of various manoeuvres on the temperature drop were also studied. They were randomized into 3 study groups, 63 cases where the babies were wiped with dry cloth alone, 37 cases where the babies were put into a plastic bag immediately after birth and lastly 41 cases where the babies were wiped with dry cloth and then inserted into a plastic bag. There was significant temperature drop in all the 3 groups maximum in the first 15 minutes and the fall continued for 1 hour after delivery (p less than 0.001). This shows that in an air-conditioned labour ward in a tropical country the temperature fall in newborn infants can be significant. This study also showed that plastic is a poor insulator against significant temperature drop.
    Matched MeSH terms: Body Temperature*
  14. Levesque DL, Tuen AA, Lovegrove BG
    PMID: 29623412 DOI: 10.1007/s00360-018-1160-7
    Much of our knowledge of the thermoregulation of endotherms has been obtained from species inhabiting cold and temperate climates, our knowledge of the thermoregulatory physiology of tropical endotherms is scarce. We studied the thermoregulatory physiology of a small, tropical mammal, the large treeshrew (Tupaia tana, Order Scandentia) by recording the body temperatures of free-ranging individuals, and by measuring the resting metabolic rates of wild individuals held temporarily in captivity. The amplitude of daily body temperature (~ 4 °C) was higher in treeshrews than in many homeothermic eutherian mammals; a consequence of high active-phase body temperatures (~ 40 °C), and relatively low rest-phase body temperatures (~ 36 °C). We hypothesized that high body temperatures enable T. tana to maintain a suitable gradient between ambient and body temperature to allow for passive heat dissipation, important in high-humidity environments where opportunities for evaporative cooling are rare. Whether this thermoregulatory phenotype is unique to Scandentians, or whether other warm-climate diurnal small mammals share similar thermoregulatory characteristics, is currently unknown.
    Matched MeSH terms: Body Temperature Regulation*
  15. 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
  16. 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


    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: Body Temperature Regulation/physiology*
  17. Ullah I, Khan I, Shafie S
    Sci Rep, 2017 04 25;7(1):1113.
    PMID: 28442747 DOI: 10.1038/s41598-017-01205-5
    Unsteady mixed convection flow of Casson fluid towards a nonlinearly stretching sheet with the slip and convective boundary conditions is analyzed in this work. The effects of Soret Dufour, viscous dissipation and heat generation/absorption are also investigated. After using some suitable transformations, the unsteady nonlinear problem is solved by using Keller-box method. Numerical solutions for wall shear stress and high temperature transfer rate are calculated and compared with previously published work, an excellent arrangement is followed. It is noticed that fluid velocity reduces for both local unsteadiness and Casson parameters. It is likewise noticed that the influence of a Dufour number of dimensionless temperature is more prominent as compared to species concentration. Furthermore, the temperature was found to be increased in the case of nonlinear thermal radiation.
    Matched MeSH terms: Body Temperature Regulation
  18. Markus Bulus, Lim, Yaik-Wah, Malsiah Hamid
    The Climatic performance of courtyard residential buildings needs to be
    investigated if the assertion that courtyard is a microclimate modifier is to be
    accepted. Therefore, this study seeks to examine the microclimatic performance
    of two existing courtyard residential buildings with similar characteristics in
    Kafanchan-Kaduna Nigeria, -the fully enclosed courtyard residential building and
    the semi-enclosed courtyard residential building. The purpose of this research is
    to investigate their microclimatic performances in other to establish the best
    courtyard house. This study uses measurement to achieve its aim. The tool
    employed for data collection is the Hobo Weather Data Loggers (HWDL). Three
    HWDL were used to collect data in the two case-study, and the third one was
    placed in the outside area as a benchmark. Only air temperature and relative
    humidity were measured. This study revealed a tangible difference in the
    microclimatic performance of the two case-study. The fully enclosed courtyard
    residential building is seen to have air temperature difference of 1 oC to 3 oC, and
    the relative humidity difference of 4 % to 8 %. In conclusion, the fully enclosed
    courtyard house demonstrated a more favorable microclimatic performance than
    the semi-enclosed, and further simulation studies towards its optimization are
    Matched MeSH terms: Body Temperature
  19. Dee, S., Singh, B., Remeli, M.F., Tan, L., Oberoi, A.
    This paper looks at electrical power generation from solar concentrator using thermoelectric generator. An experiment was conducted on a concentrator thermoelectric generator (CTEG) utilising solar thermal energy. The CTEG used a parabolic dish as concentrator with thermoelectric device installed at the focal point to convert thermal energy to generate electricity. The investigation covered the cooling effect of the cold side of the thermoelectric generator using natural and forced convection cooling for optimum output. Forced convection cooling with a fan provided 69% more power output from the CTEG system as the temperature difference across the TEG was greater than the system cooled by natural convection. The outcome of this project showed maximum power output was obtained for the CTEG system cooled by forced convection cooling.
    Matched MeSH terms: Body Temperature
  20. Haibo Jiang, Zuguo Mo, Xiongbin Hou, Haijuan Wang
    Sains Malaysiana, 2017;46:2205-2213.
    The mechanical properties of fractured rock mass are largely dependent on the fracture structure under the coupling of freeze-thaw cycles and large temperature difference. Based on the traditional macroscopic continuum theory, the thermal and mechanical model and the corresponding theories ignore the material internal structure characteristics, which add difficulty in describing the mesoscopic thermal and mechanical behavior of the fractured rock mass among different phases. In order to uncover the inherent relationship and laws among the internal crack development, structural change and the physical and mechanical properties of rock under strong cold and frost weathering in cold area, typical granite and sandstone in cold region were analyzed in laboratory tests. The SEM scanning technology was introduced to record the microstructural change of rock samples subject to freeze-thaw cycles and large temperature difference. Association rules between the microstructure and the physical mechanical properties of rock mass were analyzed. The results indicated that, with the increase of the cyclic number, the macroscopic physical and mechanical indexes and the microscopic fracture index of granite and sandstone continuously and gradually deteriorate. The width of original micro crack continues to expand and extend and new local micro cracks are generated and continue to expand. The fracture area and width of the rock increase and the strength of the rock is continuously damaged. In particular, the strength and elastic modulus of granite decrease by 20.2% and 33.36%, respectively; the strength and elastic modulus of sandstone decrease by 33.4% and 36.43%, respectively.
    Matched MeSH terms: Body Temperature
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