Blocking lncRNA HCG18 re-sensitizes Taxol resistant lung cancer cells to Taxol through modulating the miR-34a-5p/HDAC1 axis.

Lung cancer is one of the most frequently diagnosed cancers worldwide, associated with a poor survival rate. Taxol (Paclitaxel) is commonly used as a chemotherapeutic treatment for advanced lung cancers. While Taxol has improved clinical outcomes for lung cancer patients, a significant number of them develop resistance to Taxol, resulting in treatment failure. The role of the long noncoding RNA HCG18 in lung cancer and Taxol resistance has not yet been fully understood. To investigate this, we examined the expression of HCG18 and miR-34a-5p in lung tumors and normal lung tissues using qRT-PCR. We also assessed Taxol resistance through cell viability and apoptosis assays. Through the starBase online service, we analyzed the interactions between lncRNA and mRNA as well as miRNA and mRNA. We further validated the association between lncRNA and miRNA through luciferase and RNA pull-down assays. Our findings demonstrated that HCG18 was significantly upregulated in lung cancer tissues compared to normal lung tissues. Silencing HCG18 increased the sensitivity of lung cancer cells to Taxol. Additionally, our study established a Taxol-resistant cell line and observed a substantial upregulation of HCG18 in Taxol-resistant lung cancer cells. Bioinformatic analysis predicted that HCG18 could bind to miR-34a-5p, forming a competing endogenous RNA network, which was confirmed through luciferase assay. We found that miR-34a-5p was downregulated in lung cancer tissues and negatively correlated with Taxol resistance, as it directly bound to the 3'UTR region of HDAC1. Further results showed that inhibition of HCG18 significantly increased miR-34a-5p expression and sensitized lung cancer cells to Taxol. This sensitization could be reversed by inhibiting miR-34a-5p. Finally, we demonstrated in a xenograft mouse model that inhibition of HCG18 sensitized Taxol-resistant lung cancer cells to Taxol treatment by modulating the miR-34a-5p-HDAC1 axis. In conclusion, our in vitro and in vivo results uncover a novel molecular mechanism by which HCG18 promotes Taxol resistance through modulation of the miR-34a-5p/HDAC1 axis. These findings contribute to the diagnosis and treatment of chemo-resistant lung cancer.

Screening candidate diagnostic biomarkers for diabetic kidney disease.

BACKGROUND: There are big differences in treatments and prognosis between diabetic kidney disease (DKD) and non-diabetic renal disease (NDRD). However, DKD patients couldn't be diagnosed early due to lack of special biomarkers. Urine is an ideal non-invasive sample for screening DKD biomarkers. This study aims to explore DKD special biomarkers by urinary proteomics. MATERIALS AND METHODS: According to the result of renal biopsy, 142 type 2 diabetes mellitus (T2DM) patients were divided into 2 groups: DKD (n = 83) and NDRD (n = 59). Ten patients were selected from each group to define urinary protein profiles by label-free quantitative proteomics. The candidate proteins were further verifyied by parallel reaction monitoring (PRM) methods (n = 40). Proteins which perform the same trend both in PRM and proteomics were verified by enzyme-linked immunosorbent assays (ELISA) with expanding the sample size (n = 82). The area under the receiver operating characteristic curve (AUC) was used to evaluate the accuracy of diagnostic biomarkers. RESULTS: We identified 417 peptides in urinary proteins showing significant difference between DKD and NDRD. PRM verification identified C7, SERPINA4, IGHG1, SEMG2, PGLS, GGT1, CDH2, CDH1 was consistent with the proteomic results and p < 0.05. Three potential biomarkers for DKD, C7, SERPINA4, and gGT1, were verified by ELISA. The combinatied SERPINA4/Ucr and gGT1/Ucr (AUC = 0.758, p = 0.001) displayed higher diagnostic efficiency than C7/Ucr (AUC = 0.632, p = 0.048), SERPINA4/Ucr (AUC = 0.661, p = 0.032), and gGT1/Ucr (AUC = 0.661, p = 0.029) respectively. CONCLUSIONS: The combined index SERPINA4/Ucr and gGT1/Ucr can be considered as candidate biomarkers for diabetic nephropathy after adjusting by urine creatinine.

Construction of rod-like cobalt-pyridinedicarboxylic acid/MXene nanosheets composites for hydrogen evolution reaction and supercapacitor.

Metal-organic frameworks (MOFs) have attracted considerable attention in the field of energy storage and conversion due to their large specific surface area, regulatable pore structure and composition. However, the poor electrical conductivity and few active sites of MOFs impede their application. Herein, highly conductive MXene nanosheets are introduced to modulate the electronic conductivity and structure of rod-like Co-pyridinedicarboxylic acid (Co-PDC), and thus enhancing the electrochemical performance of MOFs. The heterostructural Co-PDC/MXene (CPM) was facily synthesized at room temperature. The as-prepared CPM-30 with 30 % MXene only requires the overpotential of 75.1 mV to achieve a current density of 10 mA cm-2 for hydrogen evolution reaction (HER), and the assembled electrolytic cell with CPM-30 and RuO2 as cathode and anode electrodes can achieve a current density of 10 mA cm-2 at a voltage of 1.65 V. In addition, CPM-10 exhibits a high specific capacitance of 583.1 F g-1 at 0.5 A g-1 and an excellent rate performance of 41.6 % at 50 A g-1. Furthermore, the assembled asymmetric supercapacitor CPM-10//AC exhibited an energy density of 15.55 Wh kg-1 at a power density of 750 W kg-1 and excellent stability with a capacitance retention rate of 95 % after 10,000 cycles. The excellent electrochemical properties of Co-PDC/MXene are attributed to the unique structure and synergistic effect of Co-PDC and MXene.

MAUNext: a lightweight segmentation network for medical images.

Objective. The primary objective of this study is to enhance medical image segmentation techniques for clinical research by prioritizing accuracy and the number of parameters.Approach. To achieve this objective, a novel codec-based MAUNext approach is devised, focusing on lightweight backbone design and the integration of skip connections utilizing multiscale, attention mechanism, and other strategic components. The approach is composed of three core modules: a multi-scale attentional convolution module for improved accuracy and parameter reduction, a collaborative neighbourhood-attention MLP encoding module to enhance segmentation performance, and a tiny skip-connected cross-layer semantic fusion module to bridge the semantic gap between encoder and decoder.Main results. The study extensively evaluates the MAUNext approach alongside eight state-of-the-art methods on three renowned datasets: Kagglelung, ISIC, and Brain. The experimental outcomes robustly demonstrate that the proposed approach surpasses other methods in terms of both parameter numbers and accuracy. This achievement holds promise for effectively addressing medical image segmentation tasks.Significance. Automated medical image segmentation, particularly in organ and lesion identification, plays a pivotal role in clinical diagnosis and treatment. Manual segmentation is resource-intensive, thus automated methods are highly valuable. The study underscores the clinical significance of automated segmentation by providing an advanced solution through the innovative MAUNext approach. This approach offers substantial improvements in accuracy and efficiency, which can significantly aid clinical decision-making and patient treatment.

Insertion of a totally implantable vascular access device in a patient with dextrocardia and colon cancer: a case report.

Colon cancer in patients with situs inversus totalis is rarely associated with dextrocardia, and chemotherapy is commonly used for treatment. Central venous access devices are used to administer intravenous fluids and chemotherapy in patients with colon cancer. Compared with peripherally inserted central catheters and Hickman-type tunneled catheters, totally implantable vascular access devices (TIVADs) are safer and more effective. However, positioning the catheter tip may be challenging in patients with dextrocardia and situs inversus. We herein describe a novel case involving a patient with dextrocardia and colon cancer who was treated by TIVAD insertion with intracavitary electrocardiography-aided tip localization.

Discovery of enhanced lattice dynamics in a single-layered hybrid perovskite.

Layered hybrid perovskites exhibit emergent physical properties and exceptional functional performances, but the coexistence of lattice order and structural disorder severely hinders our understanding of these materials. One unsolved problem regards how the lattice dynamics are affected by the dimensional engineering of the inorganic frameworks and their interaction with the molecular moieties. Here, we address this question by using a combination of spontaneous Raman scattering, terahertz spectroscopy, and molecular dynamics simulations. This approach reveals the structural dynamics in and out of equilibrium and provides unexpected observables that differentiate single- and double-layered perovskites. While no distinct vibrational coherence is observed in double-layered perovskites, an off-resonant terahertz pulse can drive a long-lived coherent phonon mode in the single-layered system. This difference highlights the dramatic change in the lattice environment as the dimension is reduced, and the findings pave the way for ultrafast structural engineering and high-speed optical modulators based on layered perovskites.

Comparative transcriptome analysis reveals the key genes and pathways involved in drought stress response of two wheat (Triticum aestivum L) varieties.

Drought stress results in significant yield losses in wheat production. Although studies have reported a number of wheat drought tolerance genes, a deeper understanding of the tolerance mechanisms is required for improving wheat tolerance against drought stress. In this study, we found that "Deguo 2" exhibited higher tolerance to drought than "Truman". Transcriptomics analysis enabled identification of 6084 and 7146 differentially expressed genes (DEGs), mainly mapping flavonoid biosynthesis, plant hormone, phenolamides and antioxidant pathways and revealed altered expression levels of about 700 genes. Exogenous melatonin application enhanced wheat tolerance against drought stress. Co-expression analysis showed that bHLH and bZIP transcription factors may be involved in the regulation of various pathway genes. Take together, these results provide new insights for us on exploring the crosstalk between phytohormones and secondary metabolites, and will deepen the understanding of the complex tolerance mechanisms against drought stress in wheat.

The Landscape of m6A Regulators in Multiple Brain Regions of Alzheimer's Disease.

Alzheimer's disease research has been conducted for many years, yet no effective cure methods have been found. N6-methyladenosine (m6A) RNA methylation, an essential post-transcriptional regulation mechanism, has been discovered to affect essential neurobiological processes, such as brain cell development and aging, which are closely related to neurodegenerative diseases such as Alzheimer's disease. The relationship between Alzheimer's disease and the m6A mechanism still needs further investigation. Our work evaluated the alteration profile of m6A regulators and their influences on Alzheimer's disease in 4 brain regions: the postcentral gyrus, superior frontal gyrus, hippocampus, and entorhinal cortex. We found that the expression levels of the m6A regulators FTO, ELAVL1, and YTHDF2 were altered in Alzheimer's disease and were related to pathological development and cognitive levels. We also assessed AD-related biological processes influenced by m6A regulators via GSEA and GSVA method. Biological Processes Gene Ontology terms including memory, cognition, and synapse-signaling were found to potentially be affected by m6A regulators in AD. We also found different m6A modification patterns in AD samples among different brain regions, mainly due to differences in m6A readers. Finally, we further evaluated the importance of AD-related regulators based on the WGCNA method, assessed their potential targets based on correlation relationships, and constructed diagnostic models in 3 of all 4 regions using hub regulators, including FTO, YTHDC1, YTHDC2, etc., and their potential targets. This work aims to provide a reference for the follow-up study of m6A and Alzheimer's disease.

[Electrocardiogram signal classification based on fusion method of residual network and self-attention mechanism].

In the diagnosis of cardiovascular diseases, the analysis of electrocardiogram (ECG) signals has always played a crucial role. At present, how to effectively identify abnormal heart beats by algorithms is still a difficult task in the field of ECG signal analysis. Based on this, a classification model that automatically identifies abnormal heartbeats based on deep residual network (ResNet) and self-attention mechanism was proposed. Firstly, this paper designed an 18-layer convolutional neural network (CNN) based on the residual structure, which helped model fully extract the local features. Then, the bi-directional gated recurrent unit (BiGRU) was used to explore the temporal correlation for further obtaining the temporal features. Finally, the self-attention mechanism was built to weight important information and enhance model's ability to extract important features, which helped model achieve higher classification accuracy. In addition, in order to mitigate the interference on classification performance due to data imbalance, the study utilized multiple approaches for data augmentation. The experimental data in this study came from the arrhythmia database constructed by MIT and Beth Israel Hospital (MIT-BIH), and the final results showed that the proposed model achieved an overall accuracy of 98.33% on the original dataset and 99.12% on the optimized dataset, which demonstrated that the proposed model can achieve good performance in ECG signal classification, and possessed potential value for application to portable ECG detection devices.

A Directional Chitosan Sound Sensor Based on Piezoelectric-Triboelectric Sensing.

Herein, we have constructed a directional sound sensor based on an anisotropic chitosan aerogel. Because of the lamellar porous structure, this chitosan aerogel exhibits a distinct anisotropic behavior, featuring the compressive stress along the direction of the parallel laminate structure, being approximately 2.6 times that in the orthogonal direction. Simultaneously, the chitosan aerogel is used as a directional sound-sensing material, which exhibits excellent acoustic-electric conversion performance with a marked difference in the direction perpendicular to the laminate structure than in the parallel direction. The CSANG has an optimum electrical output of 66 V and 9.2 µA under a sound stimulation of 150 Hz and 120 dB in the orthogonal direction of the laminate structure. Therefore, this directional chitosan sound sensor with excellent biocompatibility and sound sensitivity demonstrates promising application potential in the field of intelligent sensing and artificial cochlea.

Development of an Fe3O4 Surface-Grafted Carboxymethyl Chitosan Molecularly Imprinted Polymer for Specific Recognition and Sustained Release of Salidroside.

The choice of carrier material is critical in the study of natural drug release preparations and glycosylated magnetic molecularly imprinted materials. The stiffness and softness of the carrier material affect the efficiency of drug release and the specificity of recognition. The dual adjustable aperture-ligand in molecularly imprinted polymers (MIPs) provides the possibility of individualized design for sustained release studies. In this study, a combination of paramagnetic Fe3O4 and carboxymethyl chitosan (CC) was used to enhance the imprinting effect and improve drug delivery. A combination of tetrahydrofuran and ethylene glycol was used as a binary porogen to prepare MIP-doped Fe3O4-grafted CC (SMCMIP). Salidroside serves as the template, methacrylic acid acts as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) serves as the crosslinker. Scanning and transmission electron microscopy were used to observe the micromorphology of the microspheres. The structural and morphological parameters of the SMCMIP composites were measured, including the surface area and pore diameter distribution. In an in vitro study, we found that the SMCMIP composite had a sustained release property of 50% after 6 h of release time in comparison to the control SMCNIP. The total amounts of SMCMIP released at 25 °C and 37 °C were 77% and 86%, respectively. In vitro results showed that the release of SMCMIP followed Fickian kinetics, meaning that the rate of release is dependent on the concentration gradient, with diffusion coefficients ranging from 3.07 × 10-2 cm2/s to 5.66 × 10-3 cm2/s. The results of cytotoxicity experiments showed that the SMCMIP composite did not have any harmful effects on cell growth. The survival rates of intestinal epithelial cells (IPEC-J2) were found to be above 98%. By using the SMCMIP composite, drugs may be delivered in a sustained manner, potentially leading to improved therapeutic outcomes and reduced side effects.

Microglia-Mediated Neurovascular Unit Dysfunction in Alzheimer's Disease.

The neurovascular unit (NVU) is involved in the pathological changes in Alzheimer's disease (AD). The NVU is a structural and functional complex that maintains microenvironmental homeostasis and metabolic balance in the central nervous system. As one of the most important components of the NVU, microglia not only induce blood-brain barrier breakdown by promoting neuroinflammation, the infiltration of peripheral white blood cells and oxidative stress but also mediate neurovascular uncoupling by inducing mitochondrial dysfunction in neurons, abnormal contraction of cerebral vessels, and pericyte loss in AD. In addition, microglia-mediated dysfunction of cellular components in the NVU, such as astrocytes and pericytes, can destroy the integrity of the NVU and lead to NVU impairment. Therefore, we review the mechanisms of microglia-mediated NVU dysfunction in AD. Furthermore, existing therapeutic advancements aimed at restoring the function of microglia and the NVU in AD are discussed. Finally, we predict the role of pericytes in microglia-mediated NVU dysfunction in AD is the hotspot in the future.

New insights into mechanisms of berberine in alleviating reproductive disorders of polycystic ovary syndrome: Anti-inflammatory properties.

Polycystic ovary syndrome (PCOS) is a complex reproductive disorder that seriously harms female reproductive health and decreases quality of life. Although spontaneous or assisted ovulation occurs, women with PCOS suffer from poor-quality oocytes and embryos and lower fertilization and final pregnancy rates. Therefore, it is urgent to identify new pathological mechanisms and discover the underlying therapeutic targets for reproductive disorders associated with PCOS. Berberine, one of the famous traditional Chinese medicines, has been shown to improve ovulation and live birth rates in women with PCOS. The effects of berberine on insulin resistance and abnormal glucose and lipid metabolism for restoring the reproductive health of women with PCOS are well recognized and have been widely studied, but much less attention has been given to its anti-inflammatory properties. Chronic low-grade inflammation is the unifying feature of PCOS and may contribute to reproductive disorders in PCOS. Berberine can modulate the inflammatory state of the ovaries and uterus in PCOS. The anti-inflammatory properties of berberine may provide new insight into the mechanisms by which berberine alleviates reproductive disorders associated with PCOS. Here, we summarized the most recent insights into the anti-inflammatory properties of berberine in PCOS reproductive disorders to inspire researchers to pursue new study directions involving berberine.

Development and validation of nomograms predicting postoperative survival in patients with chromophobe renal cell carcinoma.

Objective: The purpose of our study is to construct and validate nomograms that effectively predict postoperative overall survival and cancer-specific survival for patients with chromophobe renal cell carcinoma (chRCC). Method: Clinical, social, and pathological data from 6016 patients with chRCC collected from the SEER database were screened from 2004 to 2015. They were randomly assigned to a training cohort (n = 4212) and a validation cohort (n = 1804) at a 7:3 ratio. Cox regression and least absolute shrinkage and selection operator (LASSO) analyses were used to identify the prognostic factors affecting overall survival (OS) and cancer-specific survival (CSS) and establish nomograms. Their performance was validated internally and externally by calculating Harrell's C-indexes, area under the curve (AUC), calibration, and decision curves. For external validation, samples from postoperative patients with chRCC at 3 independent centers in Xuzhou, China, were collected. Risk stratification models were built according to the total scores of each patient. Kaplan-Meier curves were generated for the low-risk, intermediate-risk, and high-risk groups to evaluate survival. Results: The C-indexes, AUC curves, and decision curves revealed the high ability of the nomograms in predicting OS and CSS, overall better than that of AJCC and TNM staging. Moreover, in internal and external validation, the calibration curves of 5-, 8-, and 10-year OS agreed with the actual survival. Kaplan-Meier curves indicated significant differences in survival rates among the 3 risk groups in OS or CSS. Conclusion: The nomograms showed favourable predictive power for OS and CSS. Thus, they should contribute to evaluating the prognosis of patients with chRCC. Furthermore, the risk stratification models established on the nomograms can guide the prognosis of patients and further treatment.

Establishing a Non-Invasive Gradeing Model for Primary IgA Nephropathy Based on Multi-Center Population.

BACKGROUND: It is necessary to adopt a special therapeutic schedule for treating IgA nephropathy (IgAN) at a distinct pathological stage. It would be helpful for treatment to know the pathological changes throughout the IgAN course; therefore, we want to establish a non-invasive method for determining the pathological grade of IgAN. METHODS: A total of 240 primary IgAN patients were recruited, and their clinical data and laboratory test results were collected. The study subjects were randomly divided into the training set (181 cases) and testing set (59 cases). The ordered logistic regression model was constructed with variables which were selected by single-factor and multi-factor stepwise regression analysis in training set, then the model was verified by testing set. RESULTS: Logistic regression analysis showed that hematuria, hemoglobin, urea, complement 3, urinary microalbumin and urinary microalbumin/creatinine are related to Lee's classification of IgAN. Using the above indicators as independent variables to establish the non-invasive grading model. The model's accuracy is as high as 82.9% (p = 0.00), and the rate of precision, recall, and specificity for each group are all above 80%. This model discriminates four classes of pathological stage corresponding to Lee's grading well. CONCLUSIONS: A non-invasive grading model for primary IgAN has been established successfully by clinical and laboratory data.

Facet-selective etching trajectories of individual semiconductor nanocrystals.

The size and shape of semiconductor nanocrystals govern their optical and electronic properties. Liquid cell transmission electron microscopy (LCTEM) is an emerging tool that can directly visualize nanoscale chemical transformations and therefore inform the precise synthesis of nanostructures with desired functions. However, it remains difficult to controllably investigate the reactions of semiconductor nanocrystals with LCTEM, because of the highly reactive environment formed by radiolysis of liquid. Here, we harness the radiolysis processes and report the single-particle etching trajectories of prototypical semiconductor nanomaterials with well-defined crystalline facets. Lead selenide nanocubes represent an isotropic structure that retains the cubic shape during etching via a layer-by-layer mechanism. The anisotropic arrow-shaped cadmium selenide nanorods have polar facets terminated by either cadmium or selenium atoms, and the transformation trajectory is driven by etching the selenium-terminated facets. LCTEM trajectories reveal how nanoscale shape transformations of semiconductors are governed by the reactivity of specific facets in liquid environments.

Snapshots of a light-induced metastable hidden phase driven by the collapse of charge order.

Nonequilibrium hidden states provide a unique window into thermally inaccessible regimes of strong coupling between microscopic degrees of freedom in quantum materials. Understanding the origin of these states allows the exploration of far-from-equilibrium thermodynamics and the development of optoelectronic devices with on-demand photoresponses. However, mapping the ultrafast formation of a long-lived hidden phase remains a longstanding challenge since the initial state is not recovered rapidly. Here, using state-of-the-art single-shot spectroscopy techniques, we present a direct ultrafast visualization of the photoinduced phase transition to both transient and long-lived hidden states in an electronic crystal, 1T-TaS2, and demonstrate a commonality in their microscopic pathways, driven by the collapse of charge order. We present a theory of fluctuation-dominated process that helps explain the nature of the metastable state. Our results shed light on the origin of this elusive state and pave the way for the discovery of other exotic phases of matter.

High-speed two-dimensional terahertz spectroscopy with echelon-based shot-to-shot balanced detection.

By using a reflective-echelon-based electro-optic sampling technique and a fast detector, we develop a two-dimensional terahertz (THz) spectrometer capable of shot-to-shot balanced readout of THz waveforms at a full 1-kHz repetition rate. To demonstrate the capabilities of this new detection scheme for high-throughput applications, we use gas-phase acetonitrile as a model system to acquire two-dimensional THz rotational spectra. The results show a two-order-of-magnitude speedup in the acquisition of multidimensional THz spectra when compared to conventional delay-scan methods while maintaining accurate retrieval of the nonlinear THz signal. Our report presents a feasible solution for bringing the technique of multidimensional THz spectroscopy into widespread practice.

Web-Based Prediction Models for Overall Survival and Cancer-Specific Survival of Patients With Primary Urachal Carcinoma: A Study Based on SEER Database.

Objective: We aimed to establish nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of patients with primary urachal carcinoma (UrC). Methods: Information on patients diagnosed with UrC from 1975 to 2018 was collected from the Surveillance, Epidemiology, and End Results (SEER) Program Research Data. The independent prognostic factors were determined using univariate and multivariate Cox regression. Backward variable elimination according to the Akaike information criterion (AIC) identified the most accurate and parsimonious model. Nomograms were built based on regression coefficients. The C-index, calibration plot, Brier score, integrated discrimination improvement (IDI), area under the receiver operating curve (AUC), and decision curve analysis (DCA) curve were used to evaluate the efficiency of models. Results: In total, 236 patients obtained from SEER were divided randomly into training and validation cohorts in a 70:30 ratio (166 and 70 patients, respectively). In the training cohort, multivariate Cox regression analysis indicated that pTNM/Sheldon/Mayo staging systems (included respectively), age, and tumor grade were independent prognostic factors for OS. A similar result was also found in CSS. While other variables, such as radiotherapy and chemotherapy, did not identify significant correlations. In predicting OS and CSS at 3- and 5- years, the nomograms based on pTNM showed superior discriminative and calibration capabilities in comparison to multiple statistical tools. The C-index values for the training cohort were 0.770 for OS and 0.806 for CSS, and similar outcomes were shown in further internal validation (C-index 0.693 for OS and 0.719 for CSS). We also discovered that the link between age at diagnosis and survival follows a U-shaped curve, indicating that the risk of poor prognosis decreases first and then increases with age. Conclusion: The efficacy of pTNM in predicting the prognosis of patients with UrC was greater than that of the Sheldon and Mayo staging system. Therefore, we recommend pTNM as the preferred system to stage UrC. The novel constructed nomograms based on pTNM, age, and tumor grade showed high accuracy and specificity and could be applied clinically to predict the prognosis of patients with UrC.

Compounding a High-Permittivity Thermoplastic Material and Its Applicability in Manufacturing of Microwave Photonic Crystals.

Additive Manufacturing (AM) techniques allow the production of complex geometries unattainable through other traditional technologies. This advantage lends itself well to rapidly iterating and improving upon the design of microwave photonic crystals, which are structures with intricate, repeating features. The issue tackled by this work involves compounding a high-permittivity material that can be used to produce 3D microwave photonic structures using polymer extrusion-based AM techniques. This material was acrylonitrile butadiene styrene (ABS)-based and used barium titanate (BaTiO3) ceramic as the high-permittivity component of the composite and involved the use of a surfactant and a plasticizer to facilitate processing. Initial small amounts of the material were compounded using an internal batch mixer and studied using polymer thermal analysis techniques, such as thermogravimetric analysis, rheometry, and differential scanning calorimetry to determine the proper processing conditions. The production of the material was then scaled up using a twin-screw extruder system, producing homogeneous pellets. Finally, the thermoplastic composite was used with a screw-based, material extrusion additive manufacturing technique to produce a slab for measuring the relative permittivity of the material, as well as a preliminary 3D photonic crystal. The real part of the permittivity was measured to be 12.85 (loss tangent = 0.046) in the range of 10 to 12 GHz, representing the highest permittivity ever demonstrated for a thermoplastic AM composite at microwave frequencies.