Terahertz reflectarray antennas: An overview of the state-of-the-art technology

A reflectarray antenna combines the advantages of reflectors and phased-arrays. Due to its low profile, low loss, and versatile radiation properties, it has emerged as a new generation of high-gain antennas. Meanwhile, terahertz (THz) technology, which locates between microwave and infrared, is a frontier of the state-of-the-art electromagnetic research. Recently, the concept of reflectarray has been extended from microwave to THz and higher frequencies. In this paper, several available design methodologies on THz reflectarray antennas are reviewed, such as printed reflectarray antenna using traditional square patch, dielectric THz reflectarray antenna, and reflectarray antenna using graphene. Moreover, the concept and design methods about infrared reflectarray and optical reflectarray are also reviewed. It is expected that this overview will help to stimulate and promote creative THz reflectarray research in the near future

Design of a Flexible Dielectric Refletarray Antenna towards THz Applications

A reflectarray antenna using flexible dielectric substrate is presented as a potential solution for high-gain THz antenna applications. The element phase compensation is achieved by appropriately tuning the flexible dielectric slab height. An equivalent circuit model is built to calculate the element reflection coefficient. A 30mm × 30mm square aperture dielectric reflectarray is then designed and analyzed. The numerical results demonstrate that this reflectarray can achieve good radiation performances; moreover the flexibility of the substrate makes the antenna suitable also for conformal situations

Glucose-derived AGEs enhance human gastric cancer metastasis through RAGE/ERK/Sp1/MMP2 cascade

Advanced glycation end products (AGEs) have been reported to take part in many cancer processes. Whether AGEs contribute to gastric cancer (GC) course and the underlying mechanism are still unclear. Here, glucose-derived AGEs are detected to be accumulated in tumor tissues and blood of patients with GC. As the receptor for AGEs, RAGE is highly expressed in cancer tissues, and closely associated with the depth of cancer invasion, lymph node metastasis and TNM stage. Both in vivo and in vitro treatment of AGEs accelerate the tumor invasion and metastasis, with upregualtion of RAGE, Specificity Protein 1 (Sp1), and MMP2 protein expression, as well as enhancement of MMP2 activity. Either RAGE-blocking antibody or Sp1-knockdown can partially block the AGEs-induced effects. Moreover, AGEs increased the phosphorylation of ERK, and reducing the phosphorylation level of ERK by MEK1/2 inhibitor decreased the expression of Sp1. These results indicate that accumulation of glucose-derived AGEs may act as one of potential risk factors for GC progression and promote the invasion and metastasis of gastric cancer partially through the activation of RAGE/ERK/Sp1/MMP2 pathway

Metasurface-Based Ultrathin Beam Splitter with Variable Split Angle and Power Distribution

Metasurfaces are artificial electromagnetic surfaces that consist of subwavelength scatterers in an array configuration, exhibiting exceptional abilities to manipulate electromagnetic waves. Based on the metasurface concept, a novel beam splitter for a single-frequency same-polarization light is proposed in the visible spectrum. Using metal–dielectric–metal (MDM) scattering unit cells, an array of the circular gold nanocylinders with two different diameters is designed and fabricated on the surface which introduces phase discontinuity on the scattering wavefronts. At 240 nm thick, the flat beam splitter can efficiently reflect an incident wave toward two predesigned directions. More importantly, the split angle and power distribution between these two beams can be readily controlled by setting a proper incident angle. Compared to conventional bulky optical components, the ability of this metasurface-based beam splitter would be very desirable in integrated optical systems

Berberine Suppresses Adipocyte Differentiation via Decreasing CREB Transcriptional Activity.

Berberine, one of the major constituents of Chinese herb Rhizoma coptidis, has been demonstrated to lower blood glucose, blood lipid, and body weight in patients with type 2 diabetes mellitus. The anti-obesity effect of berberine has been attributed to its anti-adipogenic activity. However, the underlying molecular mechanism remains largely unknown. In the present study, we found that berberine significantly suppressed the expressions of CCAAT/enhancer-binding protein (C/EBP)α, peroxisome proliferators-activated receptor γ2 (PPARγ2), and other adipogenic genes in the process of adipogenesis. Berberine decreased cAMP-response element-binding protein (CREB) phosphorylation and C/EBPβ expression at the early stage of 3T3-L1 preadipocyte differentiation. In addition, CREB phosphorylation and C/EBPβ expression induced by 3-isobutyl-1-methylxanthine (IBMX) and forskolin were also attenuated by berberine. The binding activities of cAMP responsive element (CRE) stimulated by IBMX and forskolin were inhibited by berberine. The binding of phosphorylated CREB to the promoter of C/EBPβ was abrogated by berberine after the induction of preadipocyte differentiation. These results suggest that berberine blocks adipogenesis mainly via suppressing CREB activity, which leads to a decrease in C/EBPβ-triggered transcriptional cascades

Berberine inhibits the differentiation of 3T3-L1 preadipocytes.

<p>(A) 3T3-L1 cells were induced to differentiate in the presence of various concentrations of berberine (BBR). 7 days later, the cells were stained with oil red O and photographed. (B) Oil red O staining was quantitatively analyzed. Data are presented as mean ± SD (<i>n</i> = 4). ^a<i>P</i><0.01 compared with 0 μM BBR.</p

Berberine inhibits the binding of phosphorylated CREB with the promoter of C/EBPβ.

<p>(A)3T3-L1 preadipocytes were treated with MDI for 24 h in the presence or absence of 5 μM berberine, and then were cross-lined with 1% formaldehyde. Chromatin-associated DNA was fragmented and immunoprecipitated with preimmune rabbit IgG or antibodies against phosphorylated CREB. Immunoprecipitated DNA was subjected to PCR amplification with specific primers flanking the CRE sites in the promoter region (-121 to +31). (B) The relative binding level is indicated as the percentage of input DNA. The data are from three separate experiments. ^a<i>P</i><0.01 compared with MDI.</p

Berberine decreases IBMX- and FSK-induced CRE luciferase activity.

<p>(A and B) 293T cells transfected with CRE reporter plasmid were stimulated with 0.5 mM 3-isobutyl-1-methylxanthine (IBMX) and 10 μM forskolin (FSK) in the presence or absence of 10 μM berberine for 6 h. The dual-luciferase assay was performed. (C and D) 3T3-L1 cells transfected with CRE reporter plasmid were stimulated with 0.5 mM IBMX and 10 μM FSK in the presence of the indicated concentrations of berberine for 12 h. The dual-luciferase assay was performed. (E) 100 nM insulin and 0.25 μM dexamethasone did not stimulate CRE activity in 3T3-L1 cells. (F)10 μM Compound C (CC) suppressed forskolin-stimulated CRE activity in 293T cells. Values represent mean ± SD from at least three independent experiments. ^a<i>P</i><0.05 compared with control (CON); ^b<i>P</i><0.05 compared with FSK; ^c<i>P</i><0.05 compared with IBMX; ^d<i>P</i><0.05 compared with FSK plus CC.</p

Additional file 2: of Stearoyl-CoA desaturase-1 promotes colorectal cancer metastasis in response to glucose by suppressing PTEN

Figure S2. Glucose promotes migration and invasion of SW116 cells. (A) Transwell assay of SW116 cells treated with 0 mM (G0), 5.5 mM (G5.5), 11 mM (G11) or 25 mM (G25) glucose. The scale bar is 100 μm. (B, C) Histograms show the number of migrated (B) and invasive (C) SW116 cells. (TIFF 1154 kb

Additional file 4: of Stearoyl-CoA desaturase-1 promotes colorectal cancer metastasis in response to glucose by suppressing PTEN

Figure S4. PTEN mediates SCD1-induced migration and invasion of SW116 cells. (A) Representative Western blot of SCD1, β-Catenin, STAT3, S6K and JNK in CRC cells transfected with shSCD1 or SCD1 cDNA. (B) Representative Western blot and quantification data of PTEN in SW116 cells transfected with siRNAs for PTEN (si1 and si2). (C) Representative photographs of transwell assays of shSCD1 or shNC-transfected SW116 after being transfected with PTEN siRNAs (siPTEN) or negative control scramble siRNAs (siNC). The scale bar is 100 μm. (D, E) Histograms show the numbers of migrated (D) and invasive (E) SW116 cells. (F) Representative Western blots and quantified results of SCD1, PTEN, Akt, p-Akt (Ser473), p-Akt (Thr308), E-cadherin and vimentin. (TIFF 2175 kb