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1.
Food Chem ; 336: 127624, 2021 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-32768901

RESUMEN

Recently, there is a growing interest in developing protein-enriched beverages with improved nutritional and functional properties. However, this is challenged by heat-induced aggregation and gelation of edible proteins, which limits their practical applications in high protein systems. In this study, soy protein particles (SPPs) with tunable heat stability were prepared by simply preheating soy proteins suspensions (pH 6.4 and 1% (w/v) concentration) at different temperatures and times. Results showed that heat-stabled SPPs were successfully obtained at high preheating temperatures with prolonged time. The SPPs structures were found to be highly unfolded, denatured, and compact. In addition, these particles exhibited lower viscosities and higher flow behavior index without gelation, whereas those prepared at lower preheating temperatures were found to readily gel after reheating. These results provide useful insights on how heat stable SPPs can be prepared, which extends their further application in protein-enriched beverages and relevant products.


Asunto(s)
Proteínas de Soja/química , Geles/química , Calor , Concentración de Iones de Hidrógeno , Tamaño de la Partícula , Agregado de Proteínas , Desnaturalización Proteica , Estabilidad Proteica , Reología , Compuestos de Sulfhidrilo/química , Viscosidad
2.
Chemosphere ; 262: 127924, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32805661

RESUMEN

Cr(VI) compounds at high temperature usually tend to decompose and reduce into Cr(III) due to thermodynamically instability for Cr(VI). This study found Cr(VI) could be reduced into Cr(V) instead of Cr(III) in the presence of CaO during heating solid waste containing Cr(VI). CaCrO4 is prepared and mixed with CaO as simulated solid waste containing Cr(VI). It was found that CaCrO4 reacted with CaO and formed a new product Ca5(CrO4)3O0.5 at temperature range of 800 and 1000 °C. The valence state of Cr in Ca5(CrO4)3O0.5 is determined to be +5 b y XPS analysis, and the color for new formed Cr(V) is observed in green, similar to Cr(III) compounds. The temperature and CaO are two keys to arouse the reduction reaction of Cr(VI) into Cr(V). In particular, the reduction of Cr(VI) into Cr(V) is strongly depended on temperature (800-1000 °C), this reaction can be balanced within 10 min, while prolonging sintering time has little help for promoting the reduction of Cr(VI) to Cr(V). Additionally, it was found Cr(V) can keep stable and not be re-oxidized into Cr(VI) at 800-1000 °C. Above results offers some new understanding and knowledge about the formation of Cr(V) in presence of much CaO or CaCO3 during heating solid waste containing Cr(VI).


Asunto(s)
Cromo/química , Eliminación de Residuos/métodos , Hidróxido de Calcio/química , Calefacción , Calor , Oxidación-Reducción , Residuos Sólidos , Temperatura
3.
Food Chem ; 336: 127688, 2021 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-32768904

RESUMEN

The effects of carboxymethylation, hydroxypropylation and dual enzyme hydrolysis combined with heating on some physicochemical and functional properties, and antioxidant activity of coconut cake dietary fibre (CCDF) were studied. Results showed that both the hydroxypropylation and carboxymethylation could effectively improve (p < 0.05) the water retention capacity (WRC), oil retention capacity (ORC), viscosity, α-amylase inhibition activity (α-AAIR), glucose dialysis retardation index (GDRI), cation-exchange capacity, emulsifying capacity index (ECI) and bile adsorption capacity (BAC) of CCDF. Moreover, the cellulase and hemicellulase hydrolysis combination with heating significantly enhanced (p < 0.05) the soluble dietary fibre content, WRC, emulsion stability, GDRI, α-AAIR and BAC of CCDF; but caused decrease in ORC and browning of color. In addition, improvement of total phenol content, Fe2+ chelating ability, ABTS+· and O2-· scavenging activity were obtained in carboxymethylaticted CCDF. These effects were mainly attributed to the composition and structural modifications as evident from SEM, FT-IR and XRD analysis.


Asunto(s)
Antioxidantes/química , Celulasa/metabolismo , Cocos/química , Fibras de la Dieta/análisis , Glicósido Hidrolasas/metabolismo , Calor , Adsorción , Fenómenos Químicos , Glucosa/química , Hidrólisis , Metilación , Solubilidad , Viscosidad
4.
Sci Total Environ ; 750: 141215, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-32862000

RESUMEN

This paper reports the results obtained for microwave-assisted catalytic fast pyrolysis (MACFP) of rice husk. The MACFP process employed a hierarchical catalyst prepared via a combination of organic alkali treatment (TPAOH) and the generation of an external layer of MCM-41-type mesoporous channels. We propose this catalyst which is used for the first time for pyrolysis of lignocellulosic biomass, as a tool to reduce coke agglomeration and increase hydrocarbon yields. Our results indicate that during catalyst preparation the mass fraction of cetyltrimethylammonium bromide (CTAB) has a direct effect on the content of MCM-41 formed on top of the HZSM-5 core. For MACFP, we hypothesize that the small molecules generated from thermal decomposition of rice husk react further to form aromatic and aliphatic hydrocarbons by decarbonylation, decarboxylation, oligomerization and aromatization. The highest hydrocarbon yield (60.5%) was obtained for a catalyst modified by a 2.0 mol/L TPAOH solution, with 10 wt% of CTAB (template for producing MCM-41), as well as with digestion and crystallization at 110 °C for 24 h. In addition, the highest liquid yield (47.6 wt%) was obtained at 550 °C. The relative content of hydrocarbons goes through a maximum of 60.5% with CTAB mass fraction which was higher than values obtained with MCM-41 (3.2%) and HZSM-5 (36.0%). Characterization and catalytic testing results suggest that the digestion temperature plays a more important role in the catalyst synthesis than the crystallization temperature. High digestion temperature (120 °C) decreases the overall hydrocarbon selectivity from 60.5% (110 °C) to 39.2%. The relative content of oxygenates reached the lowest value of 35.9% at the digestion and crystallization temperature of 110 °C. The synergistic effect of the MCM-41 shell and the HZSM-5 core promotes the catalytic activity, leading to outstanding deoxygenation capabilities and excellent selectivity to BTEX (52.7%).


Asunto(s)
Oryza , Pirólisis , Biocombustibles , Biomasa , Catálisis , Calor , Microondas , Dióxido de Silicio
5.
Sci Total Environ ; 751: 141779, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-32890800

RESUMEN

Climate change is a major world-wide challenge to livestock production because food security is likely to be compromised by increased heat stress of the animals. The objective of this study was to characterize, using bioclimatic indexes, two livestock regions located in an arid zone of México, and to use this information to predict the impact of global warming on animal production systems of these regions located in the state of Baja California (México). A 5-year database (i.e., 2011 to 2015) consisting of about one million data points from two zones (i.e., coast, valley) from four meteorological stations in the north of Baja California were used. Bioclimatic indexes were constructed for the four types of livestock production systems most common in this region, being: dairy cattle, beef cattle, sheep, pigs. The temperature-humidity index (THI) thresholds used to classify heat stress were determined and scaled for each livestock species as: THIbeef and THIpig 74 units; THImilk 72 units; and THIsheep 23 units. Statistical differences between indices were detected (P < 0.01) during summer for the valley and coast zones as (THIbeef = 72.9 and 51.8; THImilk = 80.6 and 67.4; THIpigs = 83.9 and 65.2; THIsheep = 29.5 and 20.1 units). Coast zone weather did not suggest vulnerability of livestock production systems to heat stress at any time of the year, but heat stress risk during summer for valley zone dairy cattle, sheep and pigs was classified as severe, but lower for feedlot cattle. Prediction models showed significant adjustment just in the coastal zone for THImilk, THIsheep, and THIsheep, suggesting more impact of global warming during summer in the coastal zone. Use of management strategies to reduce heat load of domestic animals during summer in northern Baja California is essential to maintain their productivity, with more emphasis in the valley zone.


Asunto(s)
Cambio Climático , Trastornos de Estrés por Calor , Animales , Bovinos , Trastornos de Estrés por Calor/veterinaria , Calor , Humedad , Ganado , México , Ovinos , Porcinos
6.
Food Chem ; 334: 127523, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-32721833

RESUMEN

Non-wheat cereals have become popular in the diet due to their nutritional benefits, but their application is limited by properties of their proteins. Some of these flours can be conventionally processed, but the final products are not of acceptable quality. Modification of physico-chemical properties of non-wheat flours by dry heat and extrusion represent the alternative process which can transform the flours into an adequate raw material for the bakery and confectionery industry. The aim of this study was to determine the type and extent of physico-chemical changes in modified flours whose mixtures were used successfully for bread production. Extrusion had stronger influence on chemical composition of flours than dry heating, especially on the content of fats and phenolic compounds. Extrusion also increased starch digestibility due to complete gelatinization process, making it almost equal for all flours. On the other hand, protein digestibility depends mostly on botanical origin of flour.


Asunto(s)
Grano Comestible/metabolismo , Harina/análisis , Antioxidantes/química , Pan/análisis , Digestión , Grano Comestible/química , Manipulación de Alimentos , Hordeum/química , Hordeum/metabolismo , Calor , Fenoles/química , Proteínas de Plantas/metabolismo , Secale/química , Secale/metabolismo , Sorghum/química , Sorghum/metabolismo , Almidón/metabolismo
7.
Food Chem ; 335: 127638, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32736158

RESUMEN

Using natural antioxidants instead of synthetics ones has been the tendency for retarding the oil deterioration during repeated deep frying process. Concerning this, the comparison between synthetic tertiarybutyl hydroquinone (TBHQ) and rosemary-based antioxidants in frying French fries was hereby evaluated. The quality and stability of frying oils with rosemary-based antioxidants showed higher efficiency than TBHQ regarding oxidation parameters (i.e., chemical indices, sensory, etc.), where rosmarinic acid (RA) was the most effective, followed by rosemary extracts (RE) and carnosic acid (CA). LF-NMR results were highly correlated (R2 = 0.909-0.998) to the change in physicochemical properties tested, where RA could effectively regulate the relaxation spectrum (T2) change and decrease single component relaxation time (T2W). The PCA graph of NIRS also revealed the dynamic change of antioxidant effectiveness in accordance with that obtained by chemical methods. Hence, both LF-NMR and NIRS can be expected as rapid and efficient methods for future monitoring the frying process.


Asunto(s)
Antioxidantes/química , Culinaria , Calor , Hidroquinonas/química , Rosmarinus/química , Solanum tuberosum/química , Aceite de Soja/química , Oxidación-Reducción
8.
Rev Infirm ; 69(264): 36-38, 2020 Oct.
Artículo en Francés | MEDLINE | ID: mdl-33129476

RESUMEN

Controlling the cold chain for heat-sensitive healthcare products is essential to ensure the quality and safety of the patient's medical care. In response to this issue, the Marolles Forces Medical Supply Establishment (51), a pharmaceutical distribution establishment, is developing decision support tools to enable healthcare professionals to ensure that the conditions for storing heat-sensitive products are respected as soon as they are received.


Asunto(s)
Calor , Refrigeración , Personal de Salud , Humanos
9.
Georgian Med News ; (306): 142-146, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33130662

RESUMEN

The objective of the study was to assess antibacterial activity of antibiotic-impregnated bone allograft processed according to the Marburg bone bank system. In the experiment, thermal processed bone allografts according to the Marburg bone bank system were used. They were impregnated with gentamicin. Four groups are formed depending on the impregnation method. In I and II groups, an entire femoral heads and, in III and IV perforated femoral heads were used. In groups I and III, antibiotic impregnation was carried out simultaneously with the thermal disinfection, and in groups II and IV after thermal disinfection. In the control group, the bone allografts were heat treated, then impregnated with saline. The antibiotic release was evaluated by agar diffusion test against Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonia. The results of the study indicate the presence of antimicrobial activity against S. aureus, P. aeruginosa and K. pneumonia in all groups except the control group. However, in the II and IV group, the inhibition zone was higher compared with the I and III groups (p<0.05). We conclude that the capacity of bone allografts processed according to the Marburg bone bank system to act as gentamicin carriers has been confirmed in this study. Gentamycin loaded perforated bone allograft (IV group) showed statistically higher efficacy against S. aureus, P. aeruginosa and K. pneumonia among studied groups.


Asunto(s)
Antibacterianos , Staphylococcus aureus , Aloinjertos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Gentamicinas/farmacología , Calor , Pruebas de Sensibilidad Microbiana
10.
Zhongguo Zhong Yao Za Zhi ; 45(17): 4071-4080, 2020 Sep.
Artículo en Chino | MEDLINE | ID: mdl-33164391

RESUMEN

Moxa floss is the main material of moxibustion, which plays a therapeutic role through the thermal effect of combustion. In this paper, TG/DSC thermal analysis method was used to study the characteristic parameters of combustion heat of moxa floss produced in Qichun, and the thermal therapeutic effect and mechanism of moxibustion were studied through moxibustion OA animal model. The results show that the combustion process of moxa floss can be divided into three stages: drying, combustion oxidation and carbonization, and ash burnout. The combustion properties of moxa floss are between herbaceous and woody, and tend to be woody, with flammable, slow and lasting combustion characteristics. Moxibustion can relieve the pathological state of knee joint synovium to a certain extent, reduce knee joint swelling and blood stasis in OA rats, reduce interstitial edema, and improve local inflammation. The mechanism and target point of moxibustion treatment for OA may be up-regulating TRPM3 gene to activate ion channels, affecting calcium metabolism and reducing OA swelling degree; down-regulation of GAPDH affects glucose metabolism of knee synovial cells and mediates anti-inflammatory effect. Down-regulation of pain-related gene MMP24 is helpful to relieve OA pain. Up-regulation of CTNNB1 activates Wnt/ß-catenin signaling pathway and affects differentiation and regeneration of OA chondrocytes. This study reveals the pyrolysis characteristics of moxa floss for the first time and discusses the biological effect and possible mechanism of moxibustion heat, providing new ideas for the quality evaluation of moxa floss and the mechanism of moxibustion therapy.


Asunto(s)
Moxibustión , Osteoartritis , Animales , Modelos Animales de Enfermedad , Calor , Oxidación-Reducción , Ratas
11.
Int J Biometeorol ; 64(12): 1985-1994, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33155128

RESUMEN

While the associations of heat with health outcomes is well researched, there is less consensus on the measures used to define heat exposure and the short-term and delayed impacts of different temperature metrics on health outcomes. We investigate the nonlinear and short-term relationship of three temperature metrics and reported incidence of three gastrointestinal illnesses: salmonellosis, campylobacteriosis and cryptosporidiosis in the Australian Capital Territory (ACT). We also examine the nonlinear association of these illnesses with extreme heat (5th, 75th, 90th percentile of all heat measures). Generalized linear models with Poisson regression accounting for overdispersion, seasonal and long-term trend, weekly number of outbreaks and rainfall were developed for mean and maximum weekly temperature and the heat stress index (EHIaccl). Bacterial illnesses (salmonellosis and campylobacteriosis) showed an overall positive association with extreme heat (75th and 90th percentile of all three heat measures) and an inverse association with low temperature (5th percentile). The shape of the exposure-response curve across a range of temperatures and the lagged effects varied for each disease. Modelling the short-term and delayed effects of heat using different metrics across a range of illnesses can help identify the most appropriate measure to inform local public health intervention planning for heat-related emergencies.


Asunto(s)
Benchmarking , Calor Extremo , Australia/epidemiología , Territorio de la Capital Australiana/epidemiología , Calor , Temperatura
12.
13.
Science ; 370(6512): 37-38, 2020 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-33004503

Asunto(s)
Aleaciones , Calor , Temperatura
14.
Nat Commun ; 11(1): 4945, 2020 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-33009378

RESUMEN

Spring warming substantially advances leaf unfolding and flowering time for perennials. Winter warming, however, decreases chilling accumulation (CA), which increases the heat requirement (HR) and acts to delay spring phenology. Whether or not this negative CA-HR relationship is correctly interpreted in ecosystem models remains unknown. Using leaf unfolding and flowering data for 30 perennials in Europe, here we show that more than half (7 of 12) of current chilling models are invalid since they show a positive CA-HR relationship. The possible reason is that they overlook the effect of freezing temperature on dormancy release. Overestimation of the advance in spring phenology by the end of this century by these invalid chilling models could be as large as 7.6 and 20.0 days under RCPs 4.5 and 8.5, respectively. Our results highlight the need for a better representation of chilling for the correct understanding of spring phenological responses to future climate change.


Asunto(s)
Cambio Climático , Frío , Hojas de la Planta/fisiología , Estaciones del Año , Betula/fisiología , Calor , Modelos Lineales , Modelos Biológicos
15.
Eur Rev Med Pharmacol Sci ; 24(18): 9753-9759, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33015822

RESUMEN

OBJECTIVE: The weather-related conditions change the ecosystem and pose a threat to social, economic and environmental development. It creates unprecedented or unanticipated human health problems in various places or times of the year. Africa is the world's second largest and most populous continent and has relatively changeable weather conditions. The present study aims to investigate the impact of weather conditions, heat and humidity on the incidence and mortality of COVID-19 pandemic in various regions of Africa. MATERIALS AND METHODS: In this study, 16 highly populated countries from North, South, East, West, and Central African regions were selected. The data on COVID-19 pandemic including daily new cases and new deaths were recorded from World Health Organization. The daily temperature and humidity figures were obtained from the weather web "Time and Date". The daily cases, deaths, temperature and humidity were recorded from the date of appearance of first case of "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)" in the African region, from Feb 14 to August 2, 2020. RESULTS: In African countries, the daily basis mean temperature from Feb 14, 2020 to August 2, 2020 was 26.16±0.12°C, and humidity was 57.41±0.38%. The overall results revealed a significant inverse correlation between humidity and the number of cases (r= -0.192, p<0.001) and deaths (r= -0.213, p<0.001). Similarly, a significant inverse correlation was found between temperature and the number of cases (r= -0.25, p<0.001) and deaths (r=-0.18, p<0.001). Furthermore, the regression results showed that with 1% increase in humidity the number of cases and deaths was significantly reduced by 3.6% and 3.7% respectively. Congruently, with 1°C increase in temperature, the number of cases and deaths was also significantly reduced by 15.1% and 10.5%, respectively. CONCLUSIONS: Increase in relative humidity and temperature was associated with a decrease in the number of daily cases and deaths due to COVID-19 pandemic in various African countries. The study findings on weather events and COVID-19 pandemic have an impact at African regional levels to project the incidence and mortality trends with regional weather events which will enhance public health readiness and assist in planning to fight against this pandemic.


Asunto(s)
Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/mortalidad , Calor/efectos adversos , Humedad/efectos adversos , Pandemias/estadística & datos numéricos , Neumonía Viral/epidemiología , Neumonía Viral/mortalidad , Tiempo (Meteorología) , África/epidemiología , Betacoronavirus , Humanos , Incidencia
16.
Proc Biol Sci ; 287(1931): 20201140, 2020 07 29.
Artículo en Inglés | MEDLINE | ID: mdl-33043866

RESUMEN

An improved understanding of life-history responses to current environmental variability is required to predict species-specific responses to anthopogenic climate change. Previous research has suggested that cooperation in social groups may buffer individuals against some of the negative effects of unpredictable climates. We use a 15-year dataset on a cooperative breeding arid zone bird, the southern pied babbler Turdoides bicolor, to test (i) whether environmental conditions and group size correlate with survival of young during three development stages (egg, nestling, fledgling) and (ii) whether group size mitigates the impacts of adverse environmental conditions on survival of young. Exposure to high mean daily maximum temperatures (mean Tmax) during early development was associated with reduced survival probabilities of young in all three development stages. No young survived when mean Tmax > 38°C, across all group sizes. Low survival of young at high temperatures has broad implications for recruitment and population persistence in avian communities given the rapid pace of advancing climate change. Impacts of high temperatures on survival of young were not moderated by group size, suggesting that the availability of more helpers in a group is unlikely to buffer against compromised offspring survival as average and maximum temperatures increase with rapid anthropogenic climate change.


Asunto(s)
Cambio Climático , Calor , Passeriformes , Animales , Aves , Cruzamiento
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3066-3069, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018652

RESUMEN

The goal of this study is to estimate the thermal impact of a titanium skull unit (SU) implanted on the exterior aspect of the human skull. We envision this unit to house the front-end of a fully implantable electrocorticogram (ECoG)-based bi-directional (BD) brain-computer interface (BCI). Starting from the bio-heat transfer equation with physiologically and anatomically constrained tissue parameters, we used the finite element method (FEM) implemented in COMSOL to build a computational model of the SU's thermal impact. Based on our simulations, we predicted that the SU could consume up to 75 mW of power without raising the temperature of surrounding tissues above the safe limits (increase in temperature of 1°C). This power budget by far exceeds the power consumption of our front-end prototypes, suggesting that this design can sustain the SU's ability to record ECoG signals and deliver cortical stimulation. These predictions will be used to further refine the existing SU design and inform the design of future SU prototypes.


Asunto(s)
Interfaces Cerebro-Computador , Electrocorticografía , Calor , Humanos , Prótesis e Implantes , Cráneo
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4151-4155, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018912

RESUMEN

To build a system for monitoring elderly people living alone, an important step needs to be done: identifying the presence/absence of the person being monitored and his location. Such task has several applications that we discuss in this paper, and remains very important. Several techniques were proposed in the literature. However, most of them suffer from issues related to privacy, coverage or convenience. In the current paper, we propose an infrared array sensor-based approach to detect the presence/absence of a person in a room. We used a wide angle low resolution sensor (i.e., 32×24 pixels) to collect heat-related information from the area monitored, and used Deep Learning (DL) to identify the presence of up to 3 people with an accuracy reaching 97%. Our approach also detects of the presence or absence of a person with a 100% accuracy. Nevertheless, it allows identifying the location of the detected people within a room of dimensions 4×7.4 m with a margin of 0.3 m.


Asunto(s)
Aprendizaje Profundo , Estado de Salud , Tecnología de Sensores Remotos , Anciano , Calor , Humanos , Monitoreo Fisiológico , Características de la Residencia
19.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2283-2286, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018463

RESUMEN

In this work we evaluated the maximum temperature reached by the head tissues and transducers during TTFields treatment when the thermal parameters were changed. We used Pennes' equation to obtain the temperature distribution and we ran our studies using COMSOL Multiphysics. We observed that, among the parameters we tested, changes in the scalp thermal conductivity and grey matter blood perfusion were the ones that led to the highest temperature variations.Clinical Relevance- This work shows that the uncertainty regarding the thermal parameters of biological tissues might lead to significant changes in the temperature distribution when modeling heat transfer during TTFields therapy.


Asunto(s)
Temperatura Corporal , Sustancia Gris , Calor , Cabeza , Humanos , Temperatura , Conductividad Térmica , Incertidumbre
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 6107-6110, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019364

RESUMEN

Patients with long conductive implants such as deep brain stimulation (DBS) leads are often denied access to magnetic resonance imaging (MRI) exams due to safety concerns associated with radiofrequency (RF) heating of implants. Experimental temperature measurements in tissue-mimicking gel phantoms under MRI RF exposure conditions are common practices to predict in-vivo heating in the tissue surrounding wire implants. Such experiments are both expensive-as they require access to MRI units-and time-consuming due to complex implant setups. Recently, full-wave numerical simulations, which include realistic MRI RF coil models and human phantoms, are suggested as an alternative to experiments. There is however, little literature available on the accuracy of such numerical models against direct thermal measurements. This study aimed to evaluate the agreement between simulations and measurements of temperature rise at the tips of wire implants exposed to RF exposure at 64 MHz (1.5 T) for different implant trajectories typically encountered in patients with DBS leads. Heating was assessed in seven patient-derived lead configurations using both simulations and RF heating measurements during imaging of an anthropomorphic head phantom with implanted wires. We found substantial variation in RF heating as a function of lead trajectory; there was a 9.5-fold and 9-fold increase in temperature rise from ID1 to ID7 during simulations and experimental measurements, respectively. There was a strong correlation (r2 = 0.74) between simulated and measured temperatures for different lead trajectories. The maximum difference between simulated and measured temperature was 0.26 °C with simulations overestimating the temperature rise.


Asunto(s)
Calefacción , Calor , Humanos , Imagen por Resonancia Magnética , Fantasmas de Imagen , Ondas de Radio
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