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R3991 --> 697.10 --> Atypical chemokine receptor 3 (ACKR3) is a seven transmembrane (TM) spanning heptahelical receptor that is involved in different stages of cancer progression. Unlike canonical G protein‐coupled receptors (GPCRs), ACKR3 does not couple to heterotrimeric G proteins when activated by its endogenous ligand, CXCL12. It is therefore a naturally occurring fully arrestin biased receptor. ACKR3 however desensitizes normally and contributes to cancer progression through arrestin‐mediated signaling pathways and/or by active sequestration of chemokine ligands, which blocks CXCL12‐mediated downregulation of CXCR4. Here, we report seven cryo‐electron microscopic structures of ACKR3 bound to three different agonistic ligands, including CXCL12, a potent CXCL12 variant (CXCL12LRHQ), and a small molecule agonist (CCX662). Although the chemokines bind to ACKR3 in a truly unique way, all three ligands still extend deep in the orthosteric pocket. In all the structures, the TM spans of ACKR3 assume a configuration like those of active GPCRs, although the cytoplasmic pocket is more compact in ACKR3. In addition, compared to other chemokine receptors, the structure of the intracellular loop 2 (ICL2) of ACKR3 is quite different and lacks a kink at the cytoplasmic end of TM4. This is predicted to prevent ACKR3 from binding heterotrimeric G proteins in a canonical way, thereby blocking nucleotide exchange. In summary, our structures provide insight into the promiscuous recognition of ACKR3 relative to other chemokine receptors, and into its distinct functions relative to other canonical chemokine receptors. The structure models may also guide future drug discovery efforts targeting ACKR3 for cancer therapy. [ABSTRACT FROM AUTHOR]

In this work, an 8 × 8 Discrete Cosine Transform (DCT) approach is adopted to perform DCT shrinkage, followed by modified set partitioning in hierarchical trees (SPIHT) data organization and fidelity enhancement filter for reducing the memory required to store a remote diagnosis and rapidly transmit it. The DCT shrinkage has the ability to retain the detailed characteristics of an image. By means of a simple transformation to gather the DCT spectrum data with the same frequency domain, the DCT shrinkage exploits all the characteristics of individual blocks to a global framework. In this scheme, insignificant DCT coefficients that correspond to the same spatial location in the high-frequency sub-bands can be used to reduce the redundancy by a combined function proposed in association with the modified SPIHT. Meanwhile, quad-tree decomposition and a set of morphological filters for reducing the artifacts are presented. This set of filters employs 8 predefined morphological operations, namely 4 structuring elements (SE), each of which includes both dilation and erosion operations. The voting strategy is used to select the most suitable morphological filter for each block. Simulation results show that the image compression reduced the computational complexity to only a half of the wavelet based sub-band decomposition and improved the quality of the reconstructed medical image in terms of both the peak signal-to-noise ratio (PSNR) and the perceptual results close to JPEG2000 and the original SPIHT at the same bit rate. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 49–61, 2007 [ABSTRACT FROM AUTHOR]

R3785 --> CXCR7 is a seven‐transmembrane chemokine receptor that is involved in different stages of cancer progression. Unlike canonical G‐protein coupled receptors (GPCRs), CXCR7 has not been reported to activate signaling pathways through heterotrimeric G‐proteins when it binds to its endogenous ligand, CXCL12. Thus, one of the proposed molecular mechanisms for CXCR7 in cancer progression is through arrestin‐mediated signaling and/or by active sequestration of chemokine ligands. We determined by cryo‐electron microscopy (cryo‐EM) the 3.3 Å structure of CXCR7 in complex with a higher affinity variant of CXCL12 as well as extracellularly and intracellularly directed Fabs (CID25 and CID24, respectively) used as fiducials to aid the determination. CXCL12 binds to ACKR3 in a unique way from other chemokine complexes reported to date. CID25 stabilizes the extracellular loop 2 (ECL2) of the receptor and the 30s loop of chemokine, whereas the complementarity determining region 3 (CDR3) of CID24 inserts into the cytoplasmic pocket of the receptor, which overall adopts a conformation consistent with those of other GPCRs in an active configuration. The biochemical data demonstrates that CID25 does not affect β‐arrestin recruitment, indicating that the conformation of CID25‐bound receptor is physiologically relevant. The CXCR7‐CXCL12 structure reveals the interactions formed by the N‐terminus of CXCL12 in the orthosteric binding pocket of CXCR7 and how the N‐terminus of the receptor contributes to the core β‐sheet of CXCL12. The structure model may also guide the drug discovery targeting CXCR7 in the future and help explain its perceived bias towards GRK/arrestin signaling. [ABSTRACT FROM AUTHOR]

A printed diversity dual-band planar inverted-F antenna (PIFA) mounted vertically at the edge of a PCMCIA network card (such that the protruded portion of the network card from the housing of the laptop has a minimum length) for WLAN operation in the 2.4-GHz band (2400–2484 MHz) and 5.2-GHz band (5150–5350 MHz) is presented. The diversity antenna studied comprises two back-to-back stacked PIFAs and has a low profile of 10 mm to the network card. Across the two operating bands, the measured reflection coefficient S11 and isolation S21 are all less than -14 dB (1.5:1 VSWR) and -24 dB, respectively. In addition, the measured radiation patterns of the two stacked PIFAs in general cover complementary space regions, thereby making it possible for providing spatial diversity for WLAN operation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 223–225, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11020 [ABSTRACT FROM AUTHOR]

This paper presents a low-profile broadband design of a printed quadrifilar helical antenna for the application as a broadcasting satellite receiving antenna in the frequency range of about 2.3 to 2.7 GHz. The antenna comprises four parallel printed strips excited in phase quadrature and rolled into a helical shape on a foam cylinder of diameter 22 mm and height 27.2 mm. The antenna shows broadband circular polarization (CP) operation with a 3-dB axial-ratio bandwidth of about 670 MHz or 27.9% centered at about 2.4 GHz. Good antenna gain is also obtained. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 134–136, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10698 [ABSTRACT FROM AUTHOR]

By bending a planar monopole into an inverted-U shape and short-circuiting one end to the ground, a novel low-profile monopole antenna with reduced backward radiation is obtained. The proposed antenna is easily fed by using a capacitively coupled feed, and is suitable for applications in mobile phones for providing reduced radiation toward the user's head. A prototype of the proposed antenna for DCS operation (1710–1880 MHz) is constructed, and measured and simulated results are presented. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 146–147, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10258 [ABSTRACT FROM AUTHOR]