GluR1 protects hypoxic ischemic brain damage via activating Akt signaling pathway in neonatal rats

OBJECTIVE

To investigate the role of glutamic acid receptor 1 (GluR1) in hypoxic-ischemic brain damage (HIBD) in neonatal rats and its underlying mechanism.

MATERIALS AND METHODS

7-day-old neonatal rats received right common carotid artery (CCA) ligation for the establishment of HIBD. After the operation, rats were sacrificed at different time points (0, 4, 6, 12, 24, 48, and 72 h), respectively. Meanwhile, rats in Sham group underwent similar procedures without ligation. Lentivirus-GLUR1-shRNA (LV-GLUR1 shRNA group) was constructed and then transfected into the right lateral ventricles of rats to inhibit GluR1 in vivo. Rats received LV-control injection were selected in the control group (LV-control group). After injection of Lentivirus-GLUR1-shRNA, CCA ligation was performed in rats for HIBD construction. Western blot was performed to detect the protein levels of GLUR1, Akt, p-Akt, and vascular endothelial growth factor (VEGF) in brain tissues. Cell apoptosis was measured by TUNEL staining assay.

RESULTS

After hypoxic ischemia (HI), GLUR1 expression increased gradually and reached a peak at 24 h. Meanwhile, p-Akt expression increased immediately and then gradually decreased. 24 h later, p-Akt expression increased again and peaked at 48 h. VEGF expression increased at 4 h after HI and reached a peak at 12 h. The expression levels of GLUR1, p-Akt, and VEGF in the brain tissues derived from rats transfected with LV-GLUR1 shRNA significantly decreased at both 4 h and 24 h after HI. In addition, results indicated that cell apoptosis was enhanced after LV-GLUR1 shRNA administration, suggesting the role of GLUR1 in protecting against HIBD.

CONCLUSIONS

GLUR1 exhibits a remarkable protective role in HIBD, which may be related to the activation of the Akt signaling pathway and the upregulation of VEGF after HI.

HOTAIR promotes inflammatory response after acute myocardium infarction by upregulating RAGE

OBJECTIVE

The aim of this study was to explore the role of HOTAIR in inflammatory response after acute myocardium infarction (AMI) and to investigate its underlying mechanism.

MATERIALS AND METHODS

The AMI model was first constructed in rats, and heart tissues were harvested. Expression levels of HOTAIR and receptor of advanced glycation end-products (RAGE) in rat heart were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The protein expression level of pEKR in rat heart was detected by Western blot. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rats were determined by enzyme-linked immunosorbent assay (ELISA). The hypoxia-induced H9C2 cells were used to construct the MI model in vitro. Meanwhile, the expression levels of HOTAIR and RAGE in H9C2 cells were detected. The levels of TNF-α and IL-6 in the culture medium were determined by ELISA. Rescue experiments were conducted by co-transfecting pcDNA-HOTAIR and si-RAGE in H9C2 cells. Subsequently, the levels of pERK, TNF-α, and IL-6 were detected.

RESULTS

The mRNA expression levels of HOTAIR and RAGE in the AMI group were significantly higher than those of the control group. Western blot showed remarkably higher protein levels of RAGE and pERK in AMI rats when compared with those of controls. Similarly, results of ELISA indicated that the levels of TNF-α and IL-6 in AMI rats were significantly higher than those of controls. Meanwhile, overexpression of HOTAIR in H9C2 cells remarkably elevated the expression levels of HOTAIR and RAGE. In addition, upregulated pERK, TNF-α, and IL-6 were observed in H9C2 cells overexpressing HOTAIR, which could be reversed by RAGE knockdown.

CONCLUSIONS

HOTAIR promotes inflammatory response after AMI by upregulating RAGE expression.

Effect of miR-497 on myocardial cell apoptosis in rats with myocardial ischemia/reperfusion through the MAPK/ERK signaling pathway

OBJECTIVE

The aim of this study was to investigate the effect of micro ribonucleic acid (miR)-497 on myocardial cell apoptosis in rats with myocardial ischemia/reperfusion (I/R) through the mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) signaling pathway.

MATERIALS AND METHODS

A rat model of myocardial I/R was established, myocardial cells were extracted, and miR-497 was inhibited by inhibitors and overexpressed using miRNA mimics. The cell apoptosis rate was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The interaction between miR-497 and ERK was determined by dual-luciferase reporter gene assay. The change in the protein level was measured via Western blotting (WB).

RESULTS

Up-regulation of miR-497 promoted myocardial cell apoptosis, and the 3'-untranslated region (3'-UTR) of ERK was highly conserved to combine with miR-497. The luciferase reporter gene assay showed that the transfection of miR-497 could significantly inhibit the relative luciferase activity in cells.

CONCLUSIONS

MiR-497 overexpression significantly down-regulated the ERK expression at messenger RNA (mRNA) and protein levels in cells. MiR-497 plays an important role in regulating I/R injury-induced myocardial cell apoptosis by targeting the ERK-induced apoptosis pathway.

Revealing ferroelectric switching character using deep recurrent neural networks

The ability to manipulate domains underpins function in applications of ferroelectrics. While there have been demonstrations of controlled nanoscale manipulation of domain structures to drive emergent properties, such approaches lack an internal feedback loop required for automatic manipulation. Here, using a deep sequence-to-sequence autoencoder we automate the extraction of latent features of nanoscale ferroelectric switching from piezoresponse force spectroscopy of tensile-strained PbZr_0.2Ti_0.8O₃ with a hierarchical domain structure. We identify characteristic behavior in the piezoresponse and cantilever resonance hysteresis loops, which allows for the classification and quantification of nanoscale-switching mechanisms. Specifically, we identify elastic hardening events which are associated with the nucleation and growth of charged domain walls. This work demonstrates the efficacy of unsupervised neural networks in learning features of a material’s physical response from nanoscale multichannel hyperspectral imagery and provides new capabilities in leveraging in operando spectroscopies that could enable the automated manipulation of nanoscale structures in materials.

The scale and dimensionality of imaging data means information is commonly overlooked. Here, using recurrent neural networks we understand temporal dependencies in hyperspectral imagery, enabling the observation of differences in ferroelectric switching mechanisms in PbZr_0.2Ti_0.8O₃ thin films due to formation of charged domain walls.

Baseline human gut microbiota profile in healthy people and standard reporting template

A comprehensive knowledge of the types and ratios of microbes that inhabit the healthy human gut is necessary before any kind of pre-clinical or clinical study can be performed that attempts to alter the microbiome to treat a condition or improve therapy outcome. To address this need we present an innovative scalable comprehensive analysis workflow, a healthy human reference microbiome list and abundance profile (GutFeelingKB), and a novel Fecal Biome Population Report (FecalBiome) with clinical applicability. GutFeelingKB provides a list of 157 organisms (8 phyla, 18 classes, 23 orders, 38 families, 59 genera and 109 species) that forms the baseline biome and therefore can be used as healthy controls for studies related to dysbiosis. This list can be expanded to 863 organisms if closely related proteomes are considered. The incorporation of microbiome science into routine clinical practice necessitates a standard report for comparison of an individual’s microbiome to the growing knowledgebase of “normal” microbiome data. The FecalBiome and the underlying technology of GutFeelingKB address this need. The knowledgebase can be useful to regulatory agencies for the assessment of fecal transplant and other microbiome products, as it contains a list of organisms from healthy individuals. In addition to the list of organisms and their abundances, this study also generated a collection of assembled contiguous sequences (contigs) of metagenomics dark matter. In this study, metagenomic dark matter represents sequences that cannot be mapped to any known sequence but can be assembled into contigs of 10,000 nucleotides or higher. These sequences can be used to create primers to study potential novel organisms. All data is freely available from https://hive.biochemistry.gwu.edu/gfkb and NCBI’s Short Read Archive.

Novel Antioxidant Peptides Purified from Mulberry (Morus atropurpurea Roxb.) Leaf Protein Hydrolysates with Hemolysis Inhibition Ability and Cellular Antioxidant Activity

Neutrase-hydrolysates hydrolyzed from mulberry leaf proteins were separated by ion exchange chromatography, gel filtration chromatography, and semipreparative reverse-phase HPLC. Purified fractions were analyzed for their radical scavenging activity, hemolysis inhibition ability, and cellular antioxidant activity (CAA). Three new antioxidant peptides, P1 (SVL, 317 Da), P2 (EAVQ, 445 Da), and P3 (RDY, 452 Da), were obtained from the most active HPLC fraction (R1) and identified using UPLC-QTOF-MS. These three peptides were then synthesized, and their antioxidant activities were analyzed. P1 and P2 had no ability to inhibit hemolysis of erythrocytes but did show antioxidant activity on HepG2 cells. P3 showed the highest hemolysis inhibition ability (92%) and CAA value (2204 μM QE/100 g peptide). The Tyr residues at the C-terminal region play an important role in the antioxidant activity in P3. Thus, the natural peptide R1 and synthesized P3 could be used as antioxidants and might be promising components of functional foods.

[Application of adrenalin saline local injection in endoscopic type Ⅰ tympanoplasty]

Objective: To evaluate the effect of adrenalin saline local injection on reducing bleeding in endoscopic typeⅠtympanoplasty. Method: A total of 50 patients underwent endoscopic type Ⅰtympanoplasty were prospectively enrolled and were randomly divided into 2 groups. Patients in research group were locally injected 5 ml adrenalin saline with a concentration of 1∶200 000, 15 minutes before operation. And the control group were not injected. Grafts acceptance rates, operation time, blood loss, pre- and pro- operative audiograms were compared between the two groups. Result: Compared with control group, the operative time and blood loss was less in research group. These differences were statistically significant(P<0.05). There was no significant difference in grafts acceptance rate between two groups (P>0.05). After surgery, mean air conduction threshold was increased and the air-bone gaps was decreased in both groups,and no statistical significant deference was found between the two groups(P>0.05). Conclusion: Before endoscopic type I tympanoplasty, adrenalin saline local injection can reduce blood loss significantly. This allows better operative view and experience for surgeons and less surgery damage to patients.

[Effects of modified posteromedial approach combined raft technique for posterior Pilon fractures with collapsed articular surface]

Objective: To evaluate the effects of modified posteromedial approach combined raft technique in the treatment of posterior Pilon fractures with collapsed articular surface. Methods: A retrospective analysis was conducted on the clinical data of 51 patients with posterior Pilon fractures combined with collapsed articular surface treated in West China Hospital between January 2014 and June 2017. There were 30 males and 21 females with an average age of 49 years (range, 19-66 years).Subjective assessment of the results was performed according to the pain visual analog scale (VAS).The general function recovery was assessed with American Orthopaedic Foot & Ankle Society (AOFAS) ankle hindfoot scale at the latest follow-up. The fracture reduction quality was determined according to Burwell-Charnley imaging standard by the anteroposterior(AP)/mortise X-ray view and three-dimensional CT of the ankle on the 3rd day after operation. The t-test was used to compare the normal distribution parameters. Results: Primary healing of incision and bone were obtained in all patients without loosening, breakage or infection of internal fixation in (3.7±0.7) months (range, 3-6 months). According to the Burwell-Charnley's standards, 50 cases achieved anatomical reduction, 1 case achieved fair reduction. According to AOFAS scales, the results were excellent in 41 cases, good in 9, and fair in 1; the excellent rate was 98.0%. According to the AOFAS scores, the average score was 93.6±2.2. The preoperative VAS score was 7.5±1.1, and the postoperative score was 0.3±0.7, in which the difference was statistically significant (t=31.231, P=0.000). At the last follow-up, the angle of injured side were 13.3°±3.4° in dorsal extension, 33.5°±4.7° in plantar flexion, and 46.9°±6.1° in the range, while angel of uninjured side were 19.8°±2.3°, 36.0°±5.7° and 55.6°±2.7°, respectively; there were significant differences in the up-mentioned indexes between the both sides (t=78.932, 121.231, 113.432, all P<0.05). Conclusion: Excellent short-term effectiveness can be achieved through the modified medial approach in patients with posterior Pilon fractures, which can be used to restore the ankle joint surface under direct vision; and with the raft technique, a small plate is used to fix small fragments firmly with less soft tissue complications.

[Study on the effects of target-silencing CXCR3 expression on malignant proliferation of hepatocellular carcinoma]

Objective: To explicit, the expression of chemokine receptor 3 in HCC tissues and its relationship with overall survival of patients, and to explore the effect of targeted silencing CXCR3 gene on proliferation of hepatocellular carcinoma cells and its mechanism of action. Methods: The expression of CXCR3 in 60 cases of hepatocellular carcinoma and its adjacent tissues were detected by immunohistochemistry. The clinicopathological correlations between the expression levels of CXCR3 in hepatoma tissues of liver cancer patients were analyzed and univariate Kaplan-Meier survival analysis was performed in combination with follow-up data. Huh7 hepatoma cells were infected with lentivirus LV-CXCR3-shRNA. The effects of CXCR3 deletion on proliferation of hepatoma cells were determined by CCK-8 assay and tumor-bearing nude mice experiment. Results: CXCR3 was highly expressed in HCC tissues, and the overall survival rate (OS) of patients with high CXCR3 expression was significantly lower than that of patients with low expression. After the CXCR3 gene was successfully silenced in Huh7 hepatocellular carcinoma cells, the proliferation ability of Huh7 cells was significantly inhibited in vitro, and the tumor growth rate of nude mice was slowed down, and the activity of JAK-STAT pathway in Huh7 cells was decreased, and the levels of c-MYC and Bcl-xl protein were decreased. In addition, deletion of CXCR3 can effectively inhibit IL-6-mediated JAK-STAT pathway activation. Conclusion: CXCR3 high expression indicated that the survival rate was poor, and the target silencing of CXCR3 gene could inhibit the proliferation of hepatocellular carcinoma cells and maybe related to inhibition of JAK-STAT pathway activity. CXCR3 may be a potential target for the treatment of hepatocellular carcinoma.

Reprograming Carcinoma Associated Fibroblasts by microRNAs

Carcinoma-associated fibroblasts (CAFs) are activated fibroblasts during development of several cancer types, and therefore emerge as an attractive therapeutic target for cancer therapy. Drugs such as PT-100 and sibrotuzumab that block the functions of CAFs have already been in clinical trials. However, these drugs exhibit limited efficacy in patients, partially due to the fact that currently used biomarkers for determining efficacy are not CAF-specific. Furthermore, depletion of CAFs may promote carcinogenesis and accelerate cancer progression by inducing immunosuppression and hypoxia, leading to reduced survival. Accumulating evidence demonstrates that restoring the expression of key microRNA induces the functional conversion of CAFs into normal fibroblasts by targeting different signaling pathways and metabolic mechanisms. Therefore, reprograming CAFs into normal fibroblasts by altering specific expression of microRNAs, rather than targeted ablation, may be an effective, novel strategy for cancer treatment. This review focuses on specific microRNAs involved in the transformation of CAFs as well as their multiple roles during tumorigenesis and chemo-resistance.

6-year change in resting heart rate is associated with incident type 2 diabetes mellitus

BACKGROUND AND AIMS

Elevated resting heart rate (RHR) is associated with risk of type 2 diabetes mellitus (T2DM). However, the association of change in RHR (ΔRHR) and incident T2DM is not fully elucidated. We aimed to assess the dose-response association between 6-year ΔRHR and T2DM.

METHODS AND RESULTS

A total of 12155 non-T2DM participants ≥18 years old were enrolled during 2007-2008 and followed up during 2013-2014. ΔRHR was calculated by subtracting the baseline RHR from the RHR value at 6-year follow-up. Age-, sex-, and RHR-specific relative risks (RRs) and 95% confidence intervals (CIs) for the effect of ΔRHR on incident T2DM were calculated by using modified Poisson regression models. As compared with ΔRHR of 0 beats/min, the adjusted risk of T2DM was significantly increased with RHR increment and reduced with RHR reduction. ΔRHR was positively associated with future risk of T2DM [RR per unit increase: 1.03 (1.03-1.04)]. As compared with stable change in RHR group (-5<ΔRHR<5 beats/min), for ΔRHR ≤ -10 beats/min, -10<ΔRHR ≤ -5 beats/min, 5≤ΔRHR<10 beats/min, and ΔRHR ≥10 beats/min groups, the pooled adjusted RR (95% CI) of T2DM was 0.69 (0.55-0.86), 0.90 (0.73-1.11), 1.31 (1.07-1.61), and 1.90 (1.59-2.26), respectively. This significant association still existed on subgroup analyses based on age, sex, and baseline RHR and sensitivity analyses.

CONCLUSIONS

Dynamic RHR change was significantly associated with incident T2DM. Our study suggests that RHR may be a non-invasive clinical indicator for interventions aiming to reduce incident T2DM in the general population.

Abstract P2-08-33: A novel seven-gene signature predicts prognosis in early-stage triple-negative breast cancer

Purpose:

Chemotherapy remains the only systemic treatment option for patients with triple-negative breast cancer (TNBC). However, due to the heterogeneity of TNBC, not all patients benefit from chemotherapy, especially those with early-stage disease. In order to improve prognostic assessment and reduce unnecessary adjuvant systemic therapy in these patients, we have developed a novel seven-gene signature.

Experimental Design:

With the ComBat method, we integrated the results from 150 transcriptome microarrays samples and 246 RNA-seq samples of early-stage TNBC patients, and identified mRNAs associated with recurrence-free survival (RFS) using Lasso-Cox model, We further analyzed these TNBC samples and compared them with 60 paired normal breast tissues (40 samples from RNA-seq and 20 samples from microarrays) to identify tumor-specific mRNAs. Twenty-one overlapped mRNAs of the RFS-associated mRNAs and the tumor-specific mRNAs are selected as candidate mRNAs. An additional 371 samples of frozen primary tumors were then collected from early-stage TNBC patients (mean follow-up of 45 months) and randomly divided into two sets: a training set (n = 186) and a validation (n = 185) set. Expression level of candidate mRNAs in these samples were measured using RT-qPCR assays, and a seven-gene signature was built through all subset regression in the training set. The prognostic and predictive accuracy of our signature was tested in the validation set and other public databases (GSE5327, GSE2034 and METABRIC).

Results:

Twenty-one candidate mRNAs were identified in early-stage TNBC patients, from which we developed a novel seven-gene signature (recurrence risk score [mRNA signature] = 1.108*TMEM101 - 0.213*KRT5 - 0.315*ACAN - 0.464*LCA5 + 0.446*RPP40 - 0.373*LAGE3 - 0.257*CDKL2). Patients in the training set were classified into high- or low-risk group based on our seven-gene signature and an optimum cut-off score derived from x-tile. The patients in high-risk group were more likely to suffer from recurrence (HR, 2.718; 95% confidence interval [CI], 1.928–3.726, P= 0.001), and a time-dependent receiver operating curve showed that the seven-gene mRNA signature had a better prognostic value than the clinicopathologic risk factors in both training set and validation set. The prognostic and predictive accuracy of the signature was also validated in the METABRIC and two other public GEO databases (GSE5327 and GSE2034). The time-dependent receiver operating curve showed that this signature had an area under the curve (AUC) of 0.742 (95% CI, 0.705-0.773) in METABRIC, 0.716 (95% CI, 0.682-0.739) and 0.723 (95% CI, 0.683-0.756) in GSE5327 and GSE2034 respectively.

Conclusion:

In this study, we developed a novel seven-gene signature which can provide additional prognostic information and may guidance in identifying early-stage TNBC patients eligible for adjuvant therapy or reduction of chemotherapy. To our knowledge, this is the first study investigating the prognostic potential of mRNA signature in early-stage triple-negative breast cancer. Our novel signature may provide an opportunity for de-escalating treatment in early-stage TNBC patients in the future.

Citation Format: Ren Y, Jiang Y, Zuo W, Xu X, Jin X, Ma D, Shao Z. A novel seven-gene signature predicts prognosis in early-stage triple-negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-33.

Effects of Phosphorus on Loosely Bound and Tightly Bound Extracellular Polymer Substances in Aerobic Granular Sludge

The stability of aerobic granular sludge (AGS) is closely related to its extracellular polymeric substances (EPS). In this study, the composition and physicochemical characteristics of EPS in AGS were determined to evaluate their roles in AGS stability. The study evaluated the influence of influent phosphorus concentration on EPS protein (PN), polysaccharide (PS) and orthophosphate content, zeta potential (ζ) and fluorescence spectrum (EEM) in loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS). With higher influent phosphorus concentration, the PN, PS and orthophosphate content were higher, as was the zeta potential in TB-EPS, but it had less influence on LB-EPS. Three-dimensional, synchronous fluorescence spectroscopy and fluorescence region integral (FRI) showed that protein-like substances were the primary components of LB-EPS and TB-EPS. Phosphorus had a dynamic quenching effect on EPS at a concentration between 0 mg L–1 and 17.5 mg L–1, which is the indirect production of phosphorus by cations. An increased concentration of influent phosphorus was beneficial to AGS stability

A J-shaped relation of BMI and stroke: Systematic review and dose-response meta-analysis of 4.43 million participants

BACKGROUND AND AIM

Many studies have shown increased risk of stroke with greater adiposity as measured by body mass index (BMI), but questions remain about the shape of the dose-response relation. We conducted a systematic review and meta-analysis of prospective studies to clarify the strength and shape of the dose-response relation between BMI and risk of stroke.

METHODS AND RESULTS

PubMed and Embase databases were searched for articles published up to May 11, 2018. Random-effects generalized least-squares regression models were used to estimate study-specific dose-response association, and restricted cubic splines were used to model the association. We included reports of 44 prospective cohort studies describing 102 466 incident cases among 4 432 475 participants. With a 5-unit increment in BMI, the summary relative risk for stroke incidence was 1.10 (95% confidence interval, 1.06 to 1.13; I² = 88.0%). The dose-response relation was J-shaped (P_{non-linearity} <0.001). The risk was not increased at the low BMI range (<24 kg/m²), but was increased within the high BMI range (>25 kg/m²).

CONCLUSION

Both overweight and obesity increase the risk of stroke with a J-shaped dose-response relation, and the nadir of the curve was observed at BMI 23-24 kg/m².

Purinergic Signaling Modulates Survival/Proliferation of Human Dental Pulp Stem Cells

Human dental pulp stem cells (hDPSCs) reside in postnatal dental pulp and exhibit the potential to differentiate into odontoblasts as well as neurons. However, the intercellular signaling niches necessary for hDPSC survival and self-renewal remain largely unknown. The objective of this study is to demonstrate the existence of intercellular purinergic signaling in hDPSCs and to assess the impact of purinergic signaling on hDPSC survival and proliferation. hDPSCs were isolated from extracted third molars and cultured in minimum essential medium. To demonstrate responsiveness to ATP application and inhibitions by purinergic receptor antagonists, whole cell patch-clamp recordings of ATP-induced currents were recorded from cultured hDPSCs. Immunofluorescence and enzymatic histochemistry staining were performed to assess purinergic receptor expression and ectonucleotidase activity in hDPSCs, respectively. To determine the effects of purinergic signaling on hDPSC, purinergic receptor antagonists and an ectonucleotidase inhibitor were applied in culture medium, and hDPSC survival and proliferation were assessed with DAPI staining and Ki67 immunofluorescence staining, respectively. We demonstrated that ATP application induced inward currents in hDPSCs. P2X and P2Y receptors are involved in the generation of ATP-induced inward currents. We also detected expression of NTPDase3 and ectonucleotidase activity in hDPSCs. We further demonstrated that purinergic receptors were tonically activated in hDPSCs and that inhibition of ectonucleotidase activity enhanced ATP-induced inward currents. Furthermore, we found that blocking P2Y and P2X receptors reduced-and inhibition of ecto-ATPase activity enhanced-the survival and proliferation of hDPSCs, while blocking P2X receptors alone affected only hDPSC proliferation. Autocrine/paracrine purinergic signaling is essential for hDPSC survival and proliferation. These results reveal potential targets to manipulate hDPSCs to promote tooth/dental pulp repair and regeneration.

The high-k poloidal scattering system for NSTX-U

An 8-channel, high-k poloidal far-infrared (FIR) scattering system is under development for the National Spherical Torus eXperiment Upgrade (NSTX-U). The 693 GHz poloidal scattering system replaces a 5-channel, 280 GHz high-k toroidal scattering system to study high-k electron density fluctuations on NSTX-U. The FIR probe beam launched from Bay G is aimed toward Bay L, where large aperture optics collect radiation at 8 simultaneous scattering angles ranging from 2° to 15°. The reduced wavelength in the poloidal system results in less refraction, and coupled with a new poloidal scattering geometry, extends measurement of poloidal wavenumbers from the previous limit of 7 cm^-1 up to >40 cm^-1. Steerable launch optics coupled with receiver optics that can be remotely translated in 5 axes allow the scattering volume to be placed from r/a = 0.1 out to the pedestal region (r/a ∼ 0.99) and allow for both upward and downward scattering to cover different regions of the 2D fluctuation spectrum.

Liquid crystal polymer receiver modules for electron cyclotron emission imaging on the DIII-D tokamak

A new generation of millimeter-wave heterodyne imaging receiver arrays has been developed and demonstrated on the DIII-D electron cyclotron emission imaging (ECEI) system. Improved circuit integration, improved noise performance, and enhanced shielding from out-of-band emission are made possible by using advanced liquid crystal polymer (LCP) substrates and monolithic microwave integrated circuit (MMIC) receiver chips. This array exhibits ∼15 dB additional gain and >30× reduction in noise temperature compared to previous generation ECEI arrays. Each LCP horn-waveguide module houses a 3 × 3 mm GaAs MMIC receiver chip, which consists of a low noise millimeter-wave preamplifier, balanced mixer, and IF amplifier together with a local oscillator multiplier chain driven at ∼12 GHz. A proof-of-principle partial LCP instrument with 5 poloidal channels was installed on DIII-D in 2017, with a full proof-of-principle system (20 poloidal × 8 radial channels) installed and commissioned in early 2018. The enhanced shielding of the LCP modules is seen to greatly reduce the sensitivity of ECEI signals to out-of-band microwave noise which has plagued previous ECEI studies on DIII-D. The LCP ECEI system is expected to be a valuable diagnostic tool for pedestal region measurements, focusing particularly on electron temperature evolution during edge localized mode bursting.