New Insights in Potato Leaf Freezing by Infrared Thermography.
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ABSTRACT:
SUBMITTER: Stegner M
PROVIDER: S-EPMC6914373 | biostudies-literature | 2019 Mar
REPOSITORIES: biostudies-literature
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Project description:Differentiating melanoma metastasis from benign cutaneous lesions currently requires biopsy or costly imaging, such as positron emission tomography scans. Melanoma metastases have been observed to be subjectively warmer than similarly appearing benign lesions. We hypothesized that infrared (IR) thermography would be sensitive and specific in differentiating palpable melanoma metastases from benign lesions.Seventy-four patients (36 females and 38 males) had 251 palpable lesions imaged for this pilot study. Diagnosis was determined using pathologic confirmation or clinical diagnosis. Lesions were divided into size strata for analysis: 0-5, >5-15, >15-30, and >30 mm. Images were scored on a scale from -1 (colder than the surrounding tissue) to +3 (significantly hotter than the surrounding tissue). Sensitivity and specificity were calculated for each stratum. Logistical challenges were scored.IR imaging was able to determine the malignancy of small (0-5 mm) lesions with a sensitivity of 39% and specificity of 100%. For lesions >5-15 mm, sensitivity was 58% and specificity 98%. For lesions >15-30 mm, sensitivity was 95% and specificity 100%, and for lesions >30 mm, sensitivity was 78% and specificity 89%. The positive predictive value was 88%-100% across all strata, and the negative predictive value was 95% for >15-30 mm lesions and 80% for >30 mm lesions.Malignant lesions >15 mm were differentiated from benign lesions with excellent sensitivity and specificity. IR imaging was well tolerated and feasible in a clinic setting. This pilot study shows promise in the use of thermography for the diagnosis of malignant melanoma with further potential as a noninvasive tool to follow tumor responses to systemic therapies.
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Project description:Recent advances in the noninvasive analyses of plant metabolism include stress imaging techniques, mainly developed for vegetative tissues. We explored if infrared thermography can be used to predict whether a quiescent seed will germinate or die upon water uptake. Thermal profiles of viable, aged, and dead Pisum sativum seeds were recorded, and image analysis of 22,000 images per individual seed showed that infrared thermography can detect imbibition- and germination-associated biophysical and biochemical changes. These "thermal fingerprints" vary with viability in this species and in Triticum aestivum and Brassica napus seeds. Thermogenesis of the small individual B. napus seeds was at the limit of the technology. We developed a computer model of "virtual pea seeds," that uses Monte Carlo simulation, based on the heat production of major seed storage compounds to unravel physico-chemical processes of thermogenesis. The simulation suggests that the cooling that dominates the early thermal profiles results from the dissolution of low molecular-weight carbohydrates. Moreover, the kinetics of the production of such "cooling" compounds over the following 100 h is dependent on seed viability. We also developed a deterministic tool that predicts in the first 3 hours of water uptake, when seeds can be redried and stored again, whether or not a pea seed will germinate. We believe that the early separation of individual, ungerminated seeds (live, aged, or dead) before destructive germination assessment creates unique opportunities for integrative studies on cell death, differentiation, and development.
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Project description:An atypical or irregular respiratory frequency is considered to be one of the earliest markers of physiological distress. In addition, monitoring of this vital parameter plays a major role in diagnosis of respiratory disorders, as well as in early detection of sudden infant death syndrome. Nevertheless, the current measurement modalities require attachment of sensors to the patient's body, leading to discomfort and stress. The current paper presents a new robust algorithm to remotely monitor breathing rate (BR) by using thermal imaging. This approach permits to detect and to track the region of interest (nose) as well as to estimate BR. In order to study the performance of the algorithm, and its robustness against motion and breathing disorders, three different thermal recordings of 11 healthy volunteers were acquired (sequence 1: normal breathing; sequence 2: normal breathing plus arbitrary head movements; and sequence 3: sequence of specific breathing patterns). Thoracic effort (piezoplethysmography) served as "gold standard" for validation of our results. An excellent agreement between estimated BR and ground truth was achieved. Whereas the mean correlation for sequence 1-3 were 0.968, 0.940 and 0.974, the mean absolute BR errors reached 0.33, 0.55 and 0.96 bpm (breaths per minute), respectively. In brief, this work demonstrates that infrared thermography is a promising, clinically relevant alternative for the currently available measuring modalities due to its performance and diverse remarkable advantages.
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Project description:AbstractExtending the shelf-life and ensuring microbiological safety of food products while preserving the nutritional properties are key aspects that must be addressed. Heat processing of food matrices has been the golden standard during the last decades, while certain non-thermal processing options have recently gained ground. In the present study, experimental pulsed light (PL) surface inactivation treatments of Salmonella enteritidis on almonds kernels are performed. The PL system is set to test different operative conditions, namely power (1000, 1250, and 1500 W) and frequency (1.8, 3.0, and 100.0 Hz) at different treatment times (from 5 to 250 s), which result in applied fluence doses in the 0-100 J·cm-2 range. Additionally, temperature measurements are collected at each operative condition on the almond surface (using infrared (IR) thermography) and at the superficial layer of the almond (1-mm depth using a thermocouple). The observed PL inactivation kinetics are then modelled using four different models. The best goodness-of-fit is found for the two-parameter Weibull model (R 2 > 0.98 and RMSE < 0.33 for all cases). The maximum achieved log-CFU reductions are 6.02 for the 1.8-Hz system, 4.69 for the 3.0-Hz system, and 3.66 for 100.0-Hz system. The offset between the collected temperature readings by the two sensors is contrasted against the inactivation rate (following the two-parameter Weibull model). It was found that the highest inactivation rate corresponds approximately to the point where the infrared camera detects a slowdown in the surface heating.Graphical abstractSupplementary informationThe online version contains supplementary material available at 10.1007/s11947-021-02725-9.
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Project description:Background:Patients with Parkinson's disease (PD) often show peripheral autonomic dysfunction and depositions of pathological alpha-synuclein aggregates in the skin. However, functional consequences of this skin involvement have received little attention. Objective:To determine thermographic differences in the skin between healthy controls (HCs) and PD patients on hands, feet, and trunk and to correlate findings with symptoms and signs of dysautonomia. Between-group differences in autonomic parameters and questionnaires were explored. Methods:Twenty-one PD patients and 19 HCs were examined by thermographic infrared imaging of standardized anatomical locations on the trunk and upper and lower extremities at baseline and after exposure to cold stress test (CST). Thermal recovery rates (RRs) were determined on the basis of thermograms. Correlation analyses between alterations in skin temperature and autonomic dysfunction were performed. Results:The most significant RR difference between PD patients and HCs was seen on the fifth distal phalanx 10 minutes post-CST (mean RR?±?SD: 51?±?18% vs. 70?±?23%, p?=?0.003). No between-group differences were seen in baseline or post-CST values of the feet. No correlations were seen between thermal parameters and clinical and autonomic data. In the HC group, a positive, moderate correlation was seen between post-CST recovery values on the 3rd and 5th phalanx and body mass index (BMI) (r?=?0.661, p?=?0.002). Conclusions:The PD patients exhibited significant reduction in RR compared to HC and patients also displayed altered thermal responses in multiple anatomical locations. Thus, infrared thermography could become an important future tool in investigation of autonomic deficiency in PD.
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Project description:BACKGROUND:Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freezing may be reduced in an isochoric freezing system. To explore this hypothesis, we performed a preliminary study on the isochoric freezing of a produce with which our group has experience, the potato. METHOD:Experiments were performed in an isochoric freezing device we designed. The device is robust and has no moving parts. For comparison, we used a geometrically identical isobaric freezing device. Following freezing and thawing, the samples were weighed, examined with colorimetry, and examined with microscopy. RESULTS:It was found that potatoes frozen to -5 °C in an isochoric system experienced no weight loss and limited enzymatic browning. In contrast the -5 °C isobaric frozen potato experienced substantial weight loss and substantial enzymatic browning. Microscopic analysis shows that the structural integrity of the potato is maintained after freezing in the isochoric system and impaired after freezing in the isobaric system. DISCUSSION:Tissue damage during isobaric freezing is caused by the increase in extracellular osmolality and the mechanical damage by ice crystals. Our thermodynamic analysis predicts that during isochoric freezing the intracellular osmolality remains comparable to the extracellular osmolality and that isochoric systems can be designed to eliminate the mechanical damage by ice. The results of this preliminary study seem to confirm the theoretical predictions. CONCLUSION:This is a preliminary exploratory study on isochoric freezing of food. We have shown that the quality of a food product preserved by isochoric freezing is better than the quality of food preserved to the same temperature in isobaric conditions. Obviously, more extensive research remains to be done to extend this study to lower freezing temperatures and other food items.
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Project description:Infantile hemangiomas (IH) are initially warm due to increased proliferation and perfusion then involute with apoptosis and reduced perfusion. Objective quantitative evaluation of IH treatment response is essential for improving outcomes. We applied a functional imaging method, dynamic infrared (IR) thermography, to investigate IH status versus control skin and over time.A preliminary prospective observational study was conducted among 25 subjects with superficial or mixed IHs (< 19 months) over 59 clinic visits. Infrared images of IHs and control sites, standardized color images, and three-dimensional images were obtained. Tissue responses following application and removal of a cold stress were recorded with video IR thermography. Outcomes included areas under the curve during cooling (AUCcool ) and rewarming (AUCrw ) and thermal intensity distribution maps.AUCcool and AUCrw were significantly higher and cooling rate slower for IHs versus uninvolved tissue indicating greater heat, presumably due to greater perfusion and metabolism for the IH. IR distribution maps showed specific areas of high and low temperature. Significant changes in IH thermal activity were reflected in the difference (AUCcool - AUCrw ), with 6.2 at 2.2 months increasing to 37.6 at 12.8 months. IH cooling rate increased with age, indicating slower recovery, and interpreted as reduced proliferation and/or involution.Dynamic IR thermography was a well-tolerated, quantitative functional imaging modality appropriate for the clinic, particularly when structural changes, i.e., height, volume, color, were not readily observed. It may assist in monitoring progress, individualizing treatment, and evaluating therapies.www.clinicaltrials.gov (Identifier NCT02061735).
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Project description:We investigated the thermographic findings of carpal tunnel syndrome (CTS). We enrolled 304 hands with electrodiagnostically identified CTS and 88 control hands. CTS hands were assigned to duration groups (D1, < 3 months; D2, 3‒6 months; D3, 6‒12 months; D4, ≥ 12 months) and severity groups (S1, very mild; S2, mild; S3, moderate; S4, severe). The temperature difference between the median and ulnar nerve territories (ΔM-U territories) decreased as CTS duration and severity increased. Significant differences in ΔM-U territories between the D1 and D3, D1 and D4, D2 and D4, and S1 and S4 groups (P = 0.003, 0.001, 0.001, and < 0.001, respectively) were observed. Thermal anisometry increased as CTS duration and severity increased. Significant differences in thermal anisometry between the D1 and D4 as well as the D2 and D4 groups (P = 0.005 and 0.04, respectively) were noted. Thermal anisometry was higher in the S4 group than in the S1, S2, and S3 groups (P = 0.009, < 0.001, and 0.003, respectively). As CTS progresses, skin temperature tends to decrease and thermal variation tends to increase in the median nerve-innervated area. Thermographic findings reflect the physiological changes of the entrapped median nerve.
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