SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Thermography

28

To map skin temperature kinetics, and by extension skin blood flow throughout normal or abnormal repair of full-thickness cutaneous wounds created on the horse body and limb, using infrared thermography.

Concepts: Scar, Wound healing, Healing, Temperature, Horse, Black body, Thermography, Thermal radiation

28

Infection with the soil-borne pathogen Fusarium oxysporum f. sp. cucumerinum (FOC), which causes Fusarium wilt of cucumber plants, might result in changes in plant transpiration and water status within leaves. To monitor leaf response in cucumber infected with FOC, digital infrared thermography (DIT) was employed to detect changes in leaf temperature. During the early stages of FOC infection, stomata closure was induced by ABA in leaves, resulting in a decreased transpiration rate and increased leaf temperature. Subsequently, cell death occurred, accompanied by water loss, resulting in a little decrease in leaf temperature. A negative correlation between transpiration rate and leaf temperature was existed. But leaf temperature exhibited a special pattern with different disease severity on light-dark cycle. Lightly wilted leaves had a higher temperature in light and a lower temperature in dark than did in healthy leaves. We identified that the water loss from wilted leaves was regulated not by stomata but rather by cells damage caused by pathogen infection. Finally, water balance in infected plants became disordered and dead tissue was dehydrated, so leaf temperature increased again. These data suggest that membrane injury caused by FOC infection induces uncontrolled water loss from damaged cells and an imbalance in leaf water status, and ultimately accelerate plant wilting. Combining detection of the temperature response of leaves to light-dark conditions, DIT not only permits noninvasive detection and indirect visualization of the development of the soil-borne disease Fusarium wilt, but also demonstrates certain internal metabolic processes correlative with water status.

Concepts: Photosynthesis, Bacteria, Fusarium oxysporum, Plant physiology, Leaf, Infrared, Transpiration, Thermography

27

BACKGROUND/PURPOSE: Infrared thermography (IRT) is a useful tool for assessing skin temperature abnormalities in patients with complex regional pain syndrome (CRPS). Although determining regions of interest (ROIs) is an essential process for interpreting thermographic images, there are no validated and standardized guidelines to determine ROIs. Therefore, ROIs may be determined differently by each observer even for the same IRT images, which can result in an important issue for IRT reliability. The purpose of this study was to investigate the interexaminer reliability of IRT in patients with CRPS. METHODS: Infrared thermographic images of 28 patients diagnosed with CRPS were reviewed by three independent examiners. The shapes, sizes, and the detailed locations of the ROIs were determined by the investigator’s own opinion based on patient history and symptoms. After maximal skin temperature of the ROI was obtained for each patient, the degree of agreement among the three examiners limbs was assessed. RESULTS: The intraclass correlation coefficient among the three independent raters was 0.865 (95% confidence interval, 0.748-0.933), indicating a high degree of reliability (P < 0.001). CONCLUSIONS: The reliability of IRT for assessing skin temperature abnormalities in CRPS was high when the ROIs were determined based on patient history and symptoms.

Concepts: Temperature, Covariance and correlation, Black body, Infrared, Thermography, Thermal radiation, Infrared thermometer, Thermographic camera

26

To evaluate the surface temperature rise using an infrared thermal imaging camera on roots with and without simulated internal resorption cavities; during canal filling with injectable (Obtura II), carrier-based (Soft-Core) gutta-percha and continuous wave of condensation (System B) techniques.

Concepts: Temperature, Heat transfer, Black body, Infrared, Thermography, Thermal radiation, Infrared thermometer, Thermographic camera

23

Infrared (IR) imaging is used to detect the subtle changes in temperature needed to accurately detect and monitor disease. Technological advances have made IR a highly sensitive and reliable detection tool with strong potential in medical and neurophotonics applications. An overview of IR imaging specifically investigating quantum well IR detectors developed at Jet Propulsion Laboratory for a noninvasive, nonradiating imaging tool is provided, which could be applied for neuroscience and neurosurgery where it involves sensitive cellular temperature change.

Concepts: Medicine, Energy, Surgery, Neuroscience, Infrared, Thermography, Jet engine, Jet Propulsion Laboratory

23

We propose a new approach in device architecture to realize bias-selectable three-color shortwave-midwave-longwave infrared photodetectors based on InAs/GaSb/AlSb type-II superlattices. The effect of conduction band off-set and different doping levels between two absorption layers are employed to control the turn-on voltage for individual channels. The optimization of these parameters leads to a successful separation of operation regimes; we demonstrate experimentally three-color photodiodes without using additional terminal contacts. As the applied bias voltage varies, the photodiodes exhibit sequentially the behavior of three different colors, corresponding to the bandgap of three absorbers. Well defined cut-offs and high quantum efficiency in each channel are achieved. Such all-in-one devices also provide the versatility of working as single or dual-band photodetectors at high operating temperature. With this design, by retaining the simplicity in device fabrication, this demonstration opens the prospect for three-color infrared imaging.

Concepts: Condensed matter physics, Temperature, Device, Solar cell, Photodiode, Infrared, Band gap, Thermography

16

Over the last years there has been a massive increase in rhinoceros poaching incidents, with more than two individuals killed per day in South Africa in the first months of 2013. Immediate actions are needed to preserve current populations and the agents involved in their protection are demanding new technologies to increase their efficiency in the field. We assessed the use of remotely piloted aircraft systems (RPAS) to monitor for poaching activities. We performed 20 flights with 3 types of cameras: visual photo, HD video and thermal video, to test the ability of the systems to detect (a) rhinoceros, (b) people acting as poachers and © to do fence surveillance. The study area consisted of several large game farms in KwaZulu-Natal province, South Africa. The targets were better detected at the lowest altitudes, but to operate the plane safely and in a discreet way, altitudes between 100 and 180 m were the most convenient. Open areas facilitated target detection, while forest habitats complicated it. Detectability using visual cameras was higher at morning and midday, but the thermal camera provided the best images in the morning and at night. Considering not only the technical capabilities of the systems but also the poacherś modus operandi and the current control methods, we propose RPAS usage as a tool for surveillance of sensitive areas, for supporting field anti-poaching operations, as a deterrent tool for poachers and as a complementary method for rhinoceros ecology research. Here, we demonstrate that low cost RPAS can be useful for rhinoceros stakeholders for field control procedures. There are, however, important practical limitations that should be considered for their successful and realistic integration in the anti-poaching battle.

Concepts: Africa, South Africa, Hunting, Infrared, Thermography, Modus operandi, KwaZulu-Natal, Surveillance

12

Acute stress triggers peripheral vasoconstriction, causing a rapid, short-term drop in skin temperature in homeotherms. We tested, for the first time, whether this response has the potential to quantify stress, by exhibiting proportionality with stressor intensity. We used established behavioural and hormonal markers: activity level and corticosterone level, to validate a mild and more severe form of an acute restraint stressor in hens (Gallus gallus domesticus). We then used infrared thermography (IRT) to non-invasively collect continuous temperature measurements following exposure to these two intensities of acute handling stress. In the comb and wattle, two skin regions with a known thermoregulatory role, stressor intensity predicted the extent of initial skin cooling, and also the occurrence of a more delayed skin warming, providing two opportunities to quantify stress. With the present, cost-effective availability of IRT technology, this non-invasive and continuous method of stress assessment in unrestrained animals has the potential to become common practice in pure and applied research.

Concepts: Time, Chicken, Black body, Red Junglefowl, Phasianidae, Grey Junglefowl, Thermography, Thermal radiation

11

E-liquids generally contain four main components: nicotine, flavours, water and carrier liquids. The carrier liquid dissolves flavours and nicotine and vaporises at a certain temperature on the atomizer of the e-cigarette. Propylene glycol and glycerol, the principal carriers used in e-liquids, undergo decomposition in contact with the atomizer heating-coil forming volatile carbonyls. Some of these, such as formaldehyde, acetaldehyde and acrolein, are of concern due to their adverse impact on human health when inhaled at sufficient concentrations. The aim of this study was to correlate the yield of volatile carbonyls emitted by e-cigarettes with the temperature of the heating coil. For this purpose, a popular commercial e-liquid was machine-vaped on a third generation e-cigarette which allowed the variation of the output wattage (5-25W) and therefore the heat generated on the atomizer heating-coil. The temperature of the heating-coil was determined by infrared thermography and the vapour generated at each temperature underwent subjective sensorial quality evaluation by an experienced vaper. A steep increase in the generated carbonyls was observed when applying a battery-output of at least 15W corresponding to 200-250°C on the heating coil. However, when considering concentrations in each inhaled puff, the short-term indoor air guideline value for formaldehyde was already exceeded at the lowest wattage of 5W, which is the wattage applied in most 2nd generation e-cigarettes. Concentrations of acetaldehyde in each puff were several times below the short-term irritation threshold value for humans. Acrolein was only detected from 20W upwards. The negative sensorial quality evaluation by the volunteering vaper of the vapour generated at 20W demonstrated the unlikelihood that such a wattage would be realistically set by a vaper. This study highlights the importance to develop standardised testing methods for the assessment of carbonyl-emissions and emissions of other potentially harmful compounds from e-cigarettes. The wide variety and variability of products available on the market make the development of such methods and the associated standardised testing conditions particularly demanding.

Concepts: Evaluation, Tobacco, Nicotine, Electronic cigarette, Diol, Propylene glycol, Glycerol, Thermography

8

In this work, we leverage graphene’s unique tunable Seebeck coefficient for the demonstration of a graphene-based thermal imaging system. By integrating graphene based photo-thermo-electric detectors with micro-machined silicon nitride membranes, we are able to achieve room temperature responsivities on the order of ~7-9 V/W (at λ=10.6 μm), with a time constant of ~23 ms. The large responsivities, due to the combination of thermal isolation and broadband infrared absorption from the underlying SiN membrane, have enabled detection as well as stand-off imaging of an incoherent blackbody target (300-500K). By comparing the fundamental achievable performance of these graphene-based thermopiles with standard thermocouple materials, we find extrapolate that graphene’s high carrier mobility can enable improved performances with respect to two main figures of merit for infrared detectors: detectivity (>8x10(8) cmHz(½)W(-1)) and noise equivalent temperature difference (<100 mK). Furthermore, even average graphene carrier mobility (<1000 cm(2)/Vs) is still sufficient to detect the emitted thermal radiation from a human target.

Concepts: Temperature, Black body, Infrared, Thermography, Thermal radiation, Infrared photography, Emissivity, Thermocouple