Natural and synthetic 2-oxoglutarate derivatives are substrates for oncogenic variants of human isocitrate dehydrogenase 1 and 2.

Variants of isocitrate dehydrogenase (IDH) 1 and 2 (IDH1/2) alter metabolism in cancer cells by catalyzing the NADPH-dependent reduction of 2-oxoglutarate (2OG) to (2R)-hydroxyglutarate. However, it is unclear how derivatives of 2OG can affect cancer cell metabolism. Here, we used synthetic C3- and C4-alkylated 2OG derivatives to investigate the substrate selectivities of the most common cancer-associated IDH1 variant (R132H IDH1), of two cancer-associated IDH2 variants (R172K IDH2, R140Q IDH2), and of WT IDH1/2. Absorbance-based, NMR, and electrochemical assays were employed to monitor WT IDH1/2 and IDH1/2 variant-catalyzed 2OG derivative turnover in the presence and absence of 2OG. Our results reveal that 2OG derivatives can serve as substrates of the investigated IDH1/2 variants, but not of WT IDH1/2, and have the potential to act as 2OG-competitive inhibitors. Kinetic parameters reveal that some 2OG derivatives, including the natural product 3-methyl-2OG, are equally or even more efficient IDH1/2 variant substrates than 2OG. Furthermore, NMR and mass spectrometry studies confirmed IDH1/2 variant-catalyzed production of alcohols in the cases of the 3-methyl-, 3-butyl-, and 3-benzyl-substituted 2OG derivatives; a crystal structure of 3-butyl-2OG with an IDH1 variant (R132C/S280F IDH1) reveals active site binding. The combined results highlight the potential for (i) IDH1/2 variant-catalyzed reduction of 2-oxoacids other than 2OG in cells, (ii) modulation of IDH1/2 variant activity by 2-oxoacid natural products, including some present in common foods, (iii) inhibition of IDH1/2 variants via active site binding rather than the established allosteric mode of inhibition, and (iv) possible use of IDH1/2 variants as biocatalysts.

Exploring the Specific Role of Iron Center in the Catalytic Activity of Human Serum Transferrin: CTAB-Induced Conformational Changes and Sequestration by Mixed Micelles.

Conformational changes play a seminal role in modulating the activity of proteins. This concept becomes all the more relevant in the context of metalloproteins, owing to the formation of specific conformation(s) induced by internal perturbations (like a change in pH, ligand binding, or receptor binding), which may carry out the binding and release of the metal ion/ions from the metal binding center of the protein. Herein, we investigated the conformational changes of an iron-binding protein, monoferric human serum transferrin (Fe-hTF), using several spectroscopic approaches. We could reversibly tune the cetyltrimethylammonium bromide (CTAB)-induced conformation of the protein, exploiting the concept of mixed micelles formed by three sequestrating agents: (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) hydrate (CHAPS) and two bile salts, namely, sodium cholate (NaC) and sodium deoxycholate (NaDC). The formation of mixed micelles between CTAB and these reagents (CHAPS/NaC/NaDC) results in the sequestration of CTAB molecules from the protein environment and aids the protein in reattaining its native-like structure. However, the guanidinium hydrochloride-induced denatured Fe-hTF did not acquire its native-like structure using these sequestrating agents, which substantiates the exclusive role of mixed micelles in the present study. Apart from this, we found that the conformation of transferrin (adopted in the presence of CTAB) displays pronounced esterase-like activity toward the para-nitrophenyl acetate (PNPA) substrate as compared to native transferrin. We also outlined the impact of the iron center and amino acids surrounding the iron center on the effective catalytic activity in the CTAB medium. We estimated ∼3 times higher specific catalytic efficiency for the iron-depleted Apo-hTF compared to the fully iron-saturated Fe2-hTF in the presence of CTAB.

Sustained exposure to high glucose induces differential expression of cellular senescence markers in murine macrophages but impairs immunosurveillance response to senescent cells secretome.

The influence of chronic diseases on various facets of macrophage cellular senescence is poorly understood. This study evaluated the impact of chronic hyperglycemia on the induction of cellular senescence and subsequent immunosurveillance functions in RAW264.7 macrophages. Macrophages were cultured under normal glucose (NG; 5 mM), high glucose (HG; 20 mM), and very high glucose (VHG; 40 mM) conditions and assessed for markers of cellular senescence. Hyperglycemia induced strong upregulation of SA-ß-gal activity, and loss of PCNA and Lamin B1 gene expression while markers of cell cycle arrest generally decreased. Non-significant changes in SASP-related proteins were observed while ROS levels slightly decreased and mitochondrial membrane potential increased. Protein concentration on the exosome membrane surface and their stability appeared to increase under hyperglycemic conditions. However, when macrophages were exposed to the secretory media (SM) of senescent preadipocytes, a dramatic increase in the levels of all inflammatory proteins was recorded especially in the VHG group that was also accompanied by upregulation of NF-κB and NLRP3 gene expression. SM treatment to hyperglycemic macrophages activated the TLR-2/Myd88 pathway but decreased the expression of scavenger receptors RAGE, CD36, and Olr-1 while CD44 and CXCL16 expression increased. On exposure to LPS, a strong upregulation in NO, ROS, and inflammatory cytokines was observed. Together, these results suggest that primary markers of cellular senescence are aberrantly expressed under chronic hyperglycemic conditions in macrophages with no significant SASP activation. Nonetheless, hyperglycemia strongly deregulates macrophage functions leading to impaired immunosurveillance of senescent cells and aggravation of inflamm-aging. This work provides novel insights into how hyperglycemia-induced dysfunctions can impact the potency of macrophages to manage senescent cell burden in aging tissues.

Ectomycorrhizas of Rhizopogon himalayensis on Cedrus deodara.

The ectomycorrhizal (EcM) roots of Cedrus deodara associated with a unique hypogeous EcM fungus-Rhizopogon himalayensis is meticulously characterized and comprehensively described based on well-established standard morphological and anatomical features. The mycobiont-R. himalayensis was found organically associated with the roots of C. deodara. The EcM morphotypes are distinguished by differences in the shape and color of the roots, type of ramification, surface texture, type of mantle, as well as different chemical reactions. All the examined morphotypes were having similar mycorrhizal system and anatomically (Mantle and Hartig net) no disparities were seen, that is, nonsignificant (p > 0.05) variations were observed. The majority of mycorrhizal systems were irregularly pinnate, dichotomous type with 0-1 order of ramification and occasional coralloid type. Mantle surface was densely cottony to loosely wooly. The outer and inner mantles were H & Q type. Hartig net was a complex net-like structure with uniseriate to mutiseriate type of hyphal cell arrangement. Rhizomorph were smooth and round, consistently growing along roots. Moreover, extraradical hyphae were hyaline, septate, and without clamp connections. Sclerotia and cystidia were absent. Our findings will contribute to the biology of ectomycorrhizae associated with primitive and economically valuable conifers, thriving in the face of shifting environmental conditions in the northwestern Himalayas.

Use of high frequency electrorotation to identify cytoplasmic changes in cells non-disruptively.

In this paper we demonstrate how the use of frequencies ranging from 50 kHz to 5 GHz in the analysis of cells by electrorotation can open the path to the identification of differences not detectable by conventional set-ups. Earlier works usually reported electrorotation devices operating below 20 MHz, limiting the response obtained to properties associated with the cell membrane. Those devices are thus unable to resolve the physiological properties in the cytoplasm. We used microwave-based technology to extend the frequency operation to 5 GHz. At high frequencies (from tens of MHz to GHz), the electromagnetic signal passes through the membrane and allows probing the cytoplasm. This enables several applications, such as cell classification, and viability analysis. Additionally, the use of conventional microfabrication techniques reduces the cost and complexity of analysis, compared to other non-invasive methods. We demonstrated the potential of this set-up by identifying two different populations of T-lymphocytes not distinguishable through visual assessment. We also assessed the effect of calcein on cell cytoplasmic properties and used it as a controlled experiment to demonstrate the possibility of this method to detect changes happening predominantly in the cytoplasm.

State-of-the-Art Room Temperature Operable Zero-Bias Schottky Diode-Based Terahertz Detector Up to 5.56 THz.

We present the characterization of a Zero-bias Schottky diode-based Terahertz (THz) detector up to 5.56 THz. The detector was operated with both a table-top system until 1.2 THz and at a Free-Electron Laser (FEL) facility at singular frequencies from 1.9 to 5.56 THz. We used two measurement techniques in order to discriminate the sub-ns-scale (via a 20 GHz oscilloscope) and the ms-scale (using the lock-in technique) responsivity. While the lock-in measurements basically contain all rectification effects, the sub-ns-scale detection with the oscilloscope is not sensitive to slow bolometric effects caused by changes of the IV characteristic due to temperature. The noise equivalent power (NEP) is 10 pW/Hz in the frequency range from 0.2 to 0.6 THz and 17 pW/Hz at 1.2 THz and increases to 0.9 µW/Hz at 5.56 THz, which is at the state of the art for room temperature zero-bias Schottky diode-based THz detectors with non-resonant antennas. The voltage and current responsivity of ∼500 kV/W and ∼100 mA/W, respectively, is demonstrated over a frequency range of 0.2 to 1.2 THz with the table-top system.

Cone-Beam Computed Tomographic Assessment of Maxillary Sinus Characteristics in Patients With Cleft Lip and Palate: A Systematic Review and Meta-Analysis.

The aim of this systematic review and meta-analysis was to evaluate the maxillary sinus characteristics of patients with cleft lip and palate (CLP).The study included manuscripts which met the following criteria: (1) study of individuals with CLP in any age group or gender and (2) study of individuals in whom assessment of maxillary sinus characteristics had been done by cone-beam computed tomography. Studies with (1) individuals having special health-care needs and (2) individuals with any syndrome affecting the development of the head and neck were excluded.In total, 11 articles were included in the review, based on the inclusion and exclusion criteria. Pooled maxillary sinus volume (MSV) on the cleft sides of patients with unilateral cleft lip and palate (UCLP) was found to be 9433.14 mm3 (95% CI, 7453.99-11 412.30), which was significantly smaller than that of controls. The meta-analyses also revealed significantly reduced MSV on the cleft sides of patients with UCLP. The differences between cleft and noncleft sides of the patients with UCLP were not found to be statistically significant. Strength-of-evidence was found to be moderate in 4 characteristics, along with 10 out of 11 articles showing low risk-of-bias.It was concluded that MSV was reduced and mucosal thickening was increased/present in patients with CLP as compared with controls. The differences between MSV of cleft and noncleft sides of the patients with UCLP could not be established. However, heterogeneity was found in terms of sample size, stratification of samples by age, and evaluation of some confounding factors.

Cyclic di-GMP sensing histidine kinase PdtaS controls mycobacterial adaptation to carbon sources.

Cell signaling relies on second messengers to transduce signals from the sensory apparatus to downstream signaling pathway components. In bacteria, one of the most important and ubiquitous second messenger is the small molecule cyclic diguanosine monophosphate (c-di-GMP). While the biosynthesis, degradation, and regulatory pathways controlled by c-di-GMP are well characterized, the mechanisms through which c-di-GMP controls these processes are not entirely understood. Herein we present the report of a c-di-GMP sensing sensor histidine kinase PdtaS (Rv3220c), which binds to c-di-GMP at submicromolar concentrations, subsequently perturbing signaling of the PdtaS-PdtaR (Rv1626) two-component system. Aided by biochemical analysis, genetics, molecular docking, FRET microscopy, and structural modelling, we have characterized the binding of c-di-GMP in the GAF domain of PdtaS. We show that a pdtaS knockout in Mycobacterium smegmatis is severely compromised in growth on amino acid deficient media and exhibits global transcriptional dysregulation. The perturbation of the c-di-GMP-PdtaS-PdtaR axis results in a cascade of cellular changes recorded by a multiparametric systems' approach of transcriptomics, unbiased metabolomics, and lipid analyses.

Macrocyclic Cavitand ß-Cyclodextrin Inhibits the Alcohol-Induced Trypsin Aggregation.

Trypsin, the most abundant pancreatic protein, aids in protein digestion by hydrolysis and exhibits aggregation propensity in presence of alcohol, which can further lead to pancreatitis and eventually pancreatic cancer. Herein, by several experimental and theoretical approaches, we unearth the inhibition of alcohol-induced aggregation of Trypsin by macrocyclic cavitand, ß-cyclodextrin (ß-CD). ß-CD interacts with the native protein and shows inhibitory effect in a dose dependent manner. Moreover, the secondary structures and morphologies of Trypsin in presence of ß-CD also clearly emphasize the inhibition of fibril formation. From Fluorescence Correlation Spectroscopy, we observed an enhancement in diffusion time of Nile Red with ∼2.5 times increase in hydrodynamic radius, substantiating the presence of fibrillar structure. Trypsin also shows reduction in its functional activity due to alcohol-induced aggregation. Our simulation data reports the probable residues responsible for fibril formation, which was validated by molecular docking studies.

Present scenarios and future prospects of herbal nanomedicine for antifungal therapy.

The current COVID-19 epidemic is a sobering reminder that human susceptibility to infectious diseases remains even in our modern civilization. After all, infectious diseases are still the major reason of death globally. Healthcare authorities have often underestimated and ignored the threat posed by "microbial dangers," although they put millions of lives at risk every year. Overlooked developing diseases including fungal infections (FIs) contribute to roughly 1.7 million fatalities per year. As many as 150 million cases of severe and potentially life-threatening FIs are reported each year. In the last few years, the number of instances has steadily increased. Most of them are invasive fungal infections that require specialized treatment and hospital care. In recent years herbal antifungal compounds have been explored to acquire effective and safe therapy against fungal infections. However, potential therapeutic effects are hampered by the poor solubility, stability, and bioavailability of these important chemicals as well as the gastric degradation that occurs in the gastrointestinal tract. To get around this issue, researchers have turned to novel drug delivery systems such as nanoemulsions, ethosomes, metallic nanoparticles, liposomes, lipid nanoparticles, transferosomes, etc by improving their limits, nanocarriers can enhance the medicinal effects of herbal oils and extracts. The present review article focuses on the available antifungal agents and their characteristics, mechanism of antifungal drugs resistance, herbal oils and extract as antifungal agents, challenges in the delivery of herbal drugs, and application of nano-drug delivery systems for effective delivery of antifungal herbal compounds.

Structural Compactness in Hen Egg White Lysozyme Induced by Bisphenol†S: A†Spectroscopic and Molecular Dynamics Simulation Approach.

The endocrine disrupting compound Bisphenol and its analogues are widely used in food packaging products and can cause serious health hazards. The protein, Lysozyme (Lyz), showing anti-microbial properties, is used as a "natural" food and dairy preservative. Herein, we explored the interaction between Lyz and Bisphenol S (BPS) by multi-spectroscopic and theoretical approaches. Lyz interacts with BPS through static quenching, where hydrophobic force governed the underlying interaction. Molecular docking results reveal that tryptophan plays a vital role in binding, corroborated well with near UV-CD studies. A decrease in the radius of gyration (from 1.43 nm to 1.35 nm) of Lyz substantiates the compactness of the protein conformation owing to such an interaction. This structural alteration experienced by Lyz may alter its functional properties as a food preservative. Consequently, this can degrade the quality of the food products and thereby lead to severe health issues.

Molecular Engineering for the Development of a Discotic Nematic Mesophase and Solid-State Emitter in Deep-Blue OLEDs.

A unique strategy for the attainment of a discotic nematic (ND) mesophase is reported consisting of a central benzene core to which are attached two 4-alkylphenyl and two 4-pentylbiphenyl moieties diagonally via alkynyl linkers. The rotational nature and incompatibility of unequal phenylethynyl units led to the disruption of π-π interactions within cores that aids to the realization of ND phase and favors high solid-state emission. When used in OLEDs, compounds act as an efficient solid-state pure deep-blue emitter with Commission Internationale de L'Eclairage (CIEx,y) coordinates of (0.16, 0.07).

Effects of fluorine substitution on substrate conversion by cytochromes P450 17A1 and 21A2.

Cytochromes P450 17A1 (CYP7A1) and 21A2 (CYP21A2) catalyze key reactions in the production of steroid hormones, including mineralocorticoids, glucocorticoids, and androgens. With the ultimate goal of designing probes that are selectively metabolized to each of these steroid types, fluorinated derivatives of the endogenous substrates, pregnenolone and progesterone, were prepared to study the effects on CYP17A1 and CYP21A2 activity. In the functional assays, the hydroxylase reactions catalysed by each of these enzymes were blocked when fluorine was introduced at the site of metabolism (positions 17 and 21 of the steroid core, respectively). CYP17A1, furthermore, performed the 17,20-lyase reaction on substrates with a fluorine installed at the 21-position. Importantly, none of the substitutions examined herein prevented compound entry into the active sites of either CYP17A1 or CYP21A2 as demonstrated by spectral binding assays. Taken together, the results suggest that fluorine might be used to redirect the metabolic pathways of pregnenolone and progesterone to specific types of steroids.

Synthesis of styryl-linked fused dihydropyridines by catalyst-free multicomponent reactions.

Herein, we report a rapid catalyst-free three-component reaction of 2-hydroxy-1,4-naphthoquinone, cinnamaldehydes and 3-aminopyrazoles in ethanol medium under reflux conditions for the easy access of styryl-linked dihydropyridines fused with naphthoquinone and pyrazole moiety. A wide variety of cinnamaldehyde derivatives and 3-aminopyrazoles were found suitable for this three-component reaction. All the products were fully characterized by spectroscopic tools and by recording single crystal XRD of one of the product. Catalyst-free reaction conditions, short reaction time, good yields of the products, easy purification process, formation of three new bonds (Two C-C and one C-N) in one-pot and products having four different bioactive moieties are the notable features of this methodology.

Does the Retromandibular Transparotid Approach Provide Quicker Access to Fracture of Mandibular Subcondyle Compared With the Retromandibular Transmasseteric Anterior Parotid Approach?

PURPOSE: Limited studies are available in the literature comparing various surgical approaches for the management of condylar fractures, and those comparing different types of retromandibular approaches are even fewer in number. This study aimed to compare the efficacy of 2 variants of the retromandibular approach-retromandibular transmasseteric anterior parotid (RMTMAP) and retromandibular transparotid (RMTP) in terms of exposure time, blood loss, facial nerve palsy, sialoceles or parotid fistula formation, infection, and esthetics of scar tissue. PATIENTS AND METHODS: A randomized controlled trial was designed in patients with mandibular subcondylar fractures requiring operative intervention. Patients were randomized into 2 groups based on a computer-generated randomization table. Group A included 37 cases, treated with the RMTMAP approach, and group B included 38 cases treated with the RMTP approach. The primary outcome variable was exposure time. Secondary outcome variables were blood loss during exposure, complications like facial nerve palsy, sialocele formation, surgical site infection, and scar esthetics. All patients were followed for 3 months. Collected data were analyzed using the χ2 and analysis of variance tests. RESULTS: The mean exposure time for fractures treated with the RMTMAP approach and RMTP approach was 21.08 ± 9.18 and 13.57 ± 6.09, respectively (P < .05). The mean blood loss for RMTMAP and RMTP approach was 11.75 ± 5.11 and 9.9 ± 3.77 mL, respectively (P = .078). No facial nerve injury was seen in patients treated with the RMTMAP approach, whereas 3 (7.8%) patients in the RMTP group had transient facial nerve injury (P = .08). CONCLUSIONS: This study concludes that the RMTP approach provides quicker access to the condyle as compared with the RMTMAP approach. However, the incidence of transient facial nerve injury was more in the RMTP approach. Except for reduced blood loss in the RMTP approach, all other parameters were comparable in both the approaches.

Is Coronoidectomy Superior to Coronoidotomy for Improving Maximum Incisal Opening in Patients With Oral Submucous Fibrosis?

PURPOSE: In the management protocol of the oral submucous fibrosis (OSMF), multiple studies have advocated that an additional step of coronoidectomy or coronoidotomy helps achieve better and more consistent postoperative results. But, there are no studies that validate if one has an advantage over the other. This study aimed to compare the outcome of the coronoidectomy with coronoidotomy for OSMF cases. METHODS: A randomized controlled trial was designed in patients with OSMF requiring operative intervention. Patients were randomized into 2 groups based on a computer-generated randomization table: group I coronoidectomy and group II coronoidotomy. The primary predictor variables were the 2 different adjunct surgical steps - coronoidectomy and coronoidotomy. The primary outcome variable was the postoperative maximum incisal opening (MIO). Secondary outcome variables were duration of surgery and blood loss. RESULTS: The study sample was composed of 32 patients (16 each group). Both the groups were comparable in terms of demographic profile. The MIO after surgery was comparable throughout the study between the groups. Repeated measures analysis of variance for comparison of mouth opening within the group showed that there was a significant improvement in postoperative MIO in both the groups (group I P value <.001 and group II P value 0.004). A statistically significant difference was found in the duration of the surgery (3.5 ± 0.73 hours vs 2.06 ± 0.87 hours) and blood loss (393 .75 ± 278.6 mL vs 90.62 ± 58.36 mL) with the shorter time and less blood loss in coronoidotomy compared with coronoidectomy. All these cases were followed for 1 year. CONCLUSIONS: Coronoidotomy as an adjunctive treatment in OSMF provides comparable treatment outcome in terms of MIO compared with coronoidectomy with the added advantage of shorter operating time and less blood loss.

Is Zygomatic Osteotomy a Viable Option to Achieve Symmetry and Stability in Post-traumatic Residual Deformity of the Zygomaticomaxillary Complex?

PURPOSE: In residual deformity cases, it is difficult to reposition the zygomaticomaxillary-complex (ZMC) intraoperatively, due to resorbed fracture edges, and lack of zygoma analysis to 3-dimensionally quantify the deformity. Instability after zygomatic osteotomy and miniplate fixation (ZOMF) due to the gap between osteotomized segments, scar tissue, muscle pull, and other factors is also unknown. The study aims to evaluate symmetry and stability after ZOMF. MATERIALS AND METHODS: In this prospective study, a ZMC analysis was designed and patients with unilateral post-traumatic residual deformity (>10 weeks) of ZMC were treated with ZOMF. Measurements were evaluated on affected and unaffected sides at preoperatively, immediately, and 6 months postoperatively using MIMICS software. The primary outcome variable was the symmetry and stability of ZMC. Secondary parameters were changes in orbital volume, diplopia, ocular motility, mouth opening, and patient satisfaction. P < .05 was considered statistically significant. The continuous variables were compared by paired t-test. The change within the continuous variable with time was assessed by repeated measure ANOVA, followed by multiple comparisons using the Bonferroni test. The changes within the categorical variable were assessed by the McNemar test. RESULTS: Ten patients were enrolled (mean age = 29.2 ± 9.97 years; male:female = 9:1; right:left = 4:6). The mean duration from trauma to surgery was 34.84 ± 31.35 weeks. There was an improvement in the symmetry in anteroposteriorly (P = .005), mediolaterally (P = .001), and at the arch (P = .011) postoperatively. All parameters remained stable at 6 months postoperatively (difference not significant, P > .05); with the median satisfaction score of 4 of 5. Significant improvement in mouth opening (P = .014) and orbital volume (P = .001) was noted. CONCLUSIONS: Virtual measurements as per the proposed protocol helped in communication and quantifying ZMC. Four-point fixation with miniplates provided enough stability over the 6-month follow-up period.

Supporting Visualization Analysis in Industrial Process Tomography by Using Augmented Reality-A Case Study of an Industrial Microwave Drying System.

Industrial process tomography (IPT) based process control is an advisable approach in industrial heating processes for improving system efficiency and quality. When using it, appropriate dataflow pipelines and visualizations are key for domain users to implement precise data acquisition and analysis. In this article, we propose a complete data processing and visualizing workflow regarding a specific case-microwave tomography (MWT) controlled industrial microwave drying system. Furthermore, we present the up-to-date augmented reality (AR) technique to support the corresponding data visualization and on-site analysis. As a pioneering study of using AR to benefit IPT systems, the proposed AR module provides straightforward and comprehensible visualizations pertaining to the process data to the related users. Inside the dataflow of the case, a time reversal imaging algorithm, a post-imaging segmentation, and a volumetric visualization module are included. For the time reversal algorithm, we exhaustively introduce each step for MWT image reconstruction and then present the simulated results. For the post-imaging segmentation, an automatic tomographic segmentation algorithm is utilized to reveal the significant information contained in the reconstructed images. For volumetric visualization, the 3D generated information is displayed. Finally, the proposed AR system is integrated with the on-going process data, including reconstructed, segmented, and volumetric images, which are used for facilitating interactive on-site data analysis for domain users. The central part of the AR system is implemented by a mobile app that is currently supported on iOS/Android platforms.

An Electromagnetic Time-Reversal Imaging Algorithm for Moisture Detection in Polymer Foam in an Industrial Microwave Drying System.

Microwave tomography (MWT) based control is a novel idea in industrial heating systems for drying polymer foam. In this work, an X-band MWT module is designed and developed using a fixed antenna array configuration and integrated with the HEPHAISTOS industrial heating system. A decomposition of the time-reversal operator (DORT) algorithm with a proper Green's function of multilayered media is utilized to localize the moisture location. The derived Green's function can be applied to the media with low or high contrast layers. It is shown that the time-reversal imaging (TRI) with the proposed Green's function can be applied to the multilayered media with a moderately rough surface. Moreover, a single frequency TRI is proposed to decrease the measurement time. Numerical results for different moisture scenarios are presented to demonstrate the efficacy of the proposed method. The developed method is then tested on the experimental data for different moisture scenarios from our developed MWT experimental prototype. Image reconstruction results show promising capabilities of the TRI algorithm in estimating the moisture location in the polymer foam.

Microwave Tomography Using Neural Networks for Its Application in an Industrial Microwave Drying System.

The article presents an application of microwave tomography (MWT) in an industrial drying system to develop tomographic-based process control. The imaging modality is applied to estimate moisture distribution in a polymer foam undergoing drying process. Our Leading challenges are fast data acquisition from the MWT sensors and real-time image reconstruction of the process. Thus, a limited number of sensors are chosen for the MWT and are placed only on top of the polymer foam to enable fast data acquisition. For real-time estimation, we present a neural network-based reconstruction scheme to estimate moisture distribution in a polymer foam. Training data for the neural network is generated using a physics-based electromagnetic scattering model and a parametric model for moisture sample generation. Numerical data for different moisture scenarios are considered to validate and test the performance of the network. Further, the trained network performance is evaluated with data from our developed prototype of the MWT sensor array. The experimental results show that the network has good accuracy and generalization capabilities.