627 research outputs found

    Guidance of Terahertz Wave over Commercial Optical Fiber

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    This work proposes a new flexible terahertz subwavelength fiber using commercial optical fiber as the core medium. The proposed dual-band fiber allows the optical signals to propagate in the innermost two layers and the THz signal to distributed over the optical fiber and mostly in the lossless foam cladding. The propagation loss at 1550 nm and 500 μm are 0.2 dB/km and 0.034 dB/mm, respectively. The proposed fiber is compact and cost-effective, making it a promising candidate for optical and terahertz fusion sensing, imaging, and nonlinear optoelectronics applications

    Broadband Single-Mode Hollow Substrate Integrated Waveguide with Photonic Crystal Sidewalls for Multilayer System-in-Package Applications

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    We numerically and experimentally demonstrate a broadband single-mode hollow substrate integrated waveguide using one-dimensional photonic crystal as sidewalls in place of metallic via holes. By avoiding the vertical metallic walls, the waveguide can be easily fabricated as a photonic crystal structure on a single planar substrate sandwiched between two parallel metal plates. Such a hybrid flat waveguide can tightly confine the millimeter and terahertz waves in the low-loss air core. With the aid of the photonic crystal sidewalls, high-order competing modes in the waveguide are substantially suppressed based on the so-called modal-filtering effect, allowing the waveguide to be operated in a single-HE 01 -mode pattern over an octave bandwidth. Benefiting from the less use of metallic walls, the propagation loss of the proposed hybrid waveguide can be less than that of the classic hollow metallic rectangular waveguide at millimeter-wave and terahertz frequencies according to our numerical simulation. A proof-of-concept experimental demonstration operating between 20 to 45 GHz is presented verifying the properties and the advantages of the proposed waveguide. This works offers a promising candidate for an octave-bandwidth single-mode transmission line for millimeter-wave and THz multilayer system-in-package applications

    Efficient free-space-to-chip coupling of ultra-wideband sub-ps THz pulse for biomolecule fingerprint sensing

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    Wide bandwidth THz pulses can be used to record the distinctive spectral fingerprints related to the vibrational or rotational modes of polycrystalline biomolecules, and can be used to resolve the time-dependent dynamics of such systems. Waveguides, owing to their tight spatial confinement of the electromagnetic fields and the longer interaction distance, are promising platforms with which to study small volumes of such systems. The efficient input of sub-ps THz pulses into waveguides is challenging owing to the wide bandwidth of the THz signal. Here, we propose a sensing chip comprised of a pair of back-to-back Vivaldi antennas feeding into, and out from, a 90° bent slotline waveguide to overcome this problem. The effective operating bandwidth of the sensing chip ranges from 0.2 to 1.15 THz, and the free-space to on-chip coupling efficiency is as high as 51% at 0.44 THz. Over the entire band, the THz signal is ∼42 dB above the noise level at room temperature, with a peak of ∼73 dB above the noise. In order to demonstrate the use of the chip, we have measured the characteristic fingerprint of α-lactose monohydrate, and its sharp absorption peak at ∼0.53 THz was successfully observed, demonstrating the promise of our technique. The chip has the merits of efficient in-plane coupling, ultra-wide bandwidth, ease-of-integration, and simple fabrication. It has the potential for large-scale manufacture, and can be a strong candidate for integration into other THz light-matter interaction platforms

    The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection—evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology

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    Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury

    Enhanced warming over the global subtropical western boundary currents

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Climate Change 2 (2012): 161-166, doi:10.1038/nclimate1353.Subtropical western boundary currents are warm, fast flowing currents that form on the western side of ocean basins. They carry warm tropical water to the mid-latitudes and vent large amounts of heat and moisture to the atmosphere along their paths, affecting atmospheric jet streams and mid-latitude storms, as well as ocean carbon uptake. The possibility that these highly energetic and nonlinear currents might change under greenhouse gas forcing has raised significant concerns, but detecting such changes is challenging owing to limited observations. Here, using reconstructed sea surface temperature datasets and newly developed century-long ocean and atmosphere reanalysis products, we find that the post-1900 surface ocean warming rate over the path of these currents is two to three times faster than the global mean surface ocean warming rate. The accelerated warming is associated with a synchronous poleward shift and/or intensification of global subtropical western boundary currents in conjunction with a systematic change in winds over both hemispheres. This enhanced warming may reduce ocean's ability to absorb anthropogenic carbon dioxide over these regions. However, uncertainties in detection and attribution of these warming trends remain, pointing to a need for a long-term monitoring network of the global western boundary currents and their extensions.This work is supported by China National Key Basic Research Project (2007CB411800) and National Natural Science Foundation Projects (40788002, 40921004). WC is supported by the Australian Climate Change Science program and the Southeast Australia Climate Initiative. HN is supported in part by the Japanese Ministry of Education, Culture, Sports, Science and Technology through Grant-in-Aid for Scientific Research on Innovative Areas #2205 and by the Japanese Ministry of Environment through Global Environment Research Fund (S-5). MJM is supported by NOAA’s Climate Program Office.2012-07-2

    Targeting ErbB2 and ErbB3 with a bispecific single-chain Fv enhances targeting selectivity and induces a therapeutic effect in vitro

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    Inappropriate signalling through the EGFR and ErbB2/HER2 members of the epidermal growth factor family of receptor tyrosine kinases is well recognised as being causally linked to a variety of cancers. Consequently, monoclonal antibodies specific for these receptors have become increasingly important components of effective treatment strategies for cancer. Increasing evidence suggests that ErbB3 plays a critical role in cancer progression and resistance to therapy. We hypothesised that co-targeting the preferred ErbB2/ErbB3 heterodimer with a bispecific single-chain Fv (bs-scFv) antibody would promote increased targeting selectivity over antibodies specific for a single tumour-associated antigen (TAA). In addition, we hypothesised that targeting this important heterodimer could induce a therapeutic effect. Here, we describe the construction and evaluation of the A5-linker-ML3.9 bs-scFv (ALM), an anti-ErbB3/ErbB2 bs-scFv. The A5-linker-ML3.9 bs-scFv exhibits selective targeting of tumour cells in vitro and in vivo that co-express the two target antigens over tumour cells that express only one target antigen or normal cells that express low levels of both antigens. The A5-linker-ML3.9 bs-scFv also exhibits significantly greater in vivo targeting of ErbB2‘+'/ErbB3‘+' tumours than derivative molecules that contain only one functional arm targeting ErbB2 or ErbB3. Binding of ALM to ErbB2‘+'/ErbB3‘+' cells mediates inhibition of tumour cell growth in vitro by effectively targeting the therapeutic anti-ErbB3 A5 scFv. This suggests both that ALM could provide the basis for an effective therapeutic agent and that engineered antibodies selected to co-target critical functional pairs of TAAs can enhance the targeting specificity and efficacy of antibody-based cancer therapeutics

    Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

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    The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

    Primary angiosarcoma of the ovary with prominent fibrosis of the ovarian stroma. Case report of an 81-year old patient

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    Primary angiosarcoma of the ovary (AS) is a rare entity with only 31 reported cases. The majority are pure angiosarcomas, the remainder are associated either with teratomas or conventional epithelial tumors. More than 50% of ovarian AS are disseminated at the time of diagnosis, the minority is detected in stage I. The prognosis of ovarian angiosarcoma in general is poor. Most reports refer to younger individuals, aged from 7 to 46 years, and only 2 case reports could be found for patients older than 64 years. Here we present a very unusual case of angiosarcoma in a 81-year-old patient

    Meta-analysis of randomized trials: evaluation of benefit from gemcitabine-based combination chemotherapy applied in advanced pancreatic cancer

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    <p>Abstract</p> <p>Background</p> <p>Single-agent gemcitabine (GEM) is a standard treatment for advanced and metastatic pancreatic cancer. This study examines the question whether GEM-based combination chemotherapy can further improve treatment efficacy.</p> <p>Methods</p> <p>A meta-analysis was performed to evaluate randomized trials comparing GEM versus GEM+X (X = cytotoxic agent). Fifteen trials including 4465 patients were eligible for an analysis of overall survival, the primary end-point of this investigation.</p> <p>Results</p> <p>The meta-analysis revealed a significant survival benefit for GEM+X with a pooled hazard ratio (HR) of 0.91 (95% CI: 0.85 – 0.97, p = 0.004). The overall test for heterogeneity resulted in p = 0.82 (I<sup>2 </sup>= 0%). The analysis of platinum-based combinations indicated a HR of 0.85 (95% CI: 0.76 – 0.96, p = 0.010), while for fluoropyrimidine-based combinations the HR was 0.90 (95% CI: 0.81 – 0.99, p = 0.030). No risk reduction was observed in the group of trials combining GEM with irinotecan, exatecan or pemetrexed (HR = 0.99). A meta-analysis of the trials with adequate information on baseline performance status (PS) was performed in five trials with 1682 patients. This analysis indicated that patients with a good PS had a marked survival benefit when receiving combination chemotherapy (HR = 0.76; 95% CI: 0.67 – 0.87; p < 0.0001). By contrast, application of combination chemotherapy to patients with an initially poor PS appeared to be ineffective (HR = 1.08; 95% CI: 0.90 – 1.29, p = 0.40).</p> <p>Conclusion</p> <p>The meta-analysis of randomized trials indicated a significant survival benefit when GEM was either combined with platinum analogs or fluoropyrimidines. Based on a preliminary subgroup analysis (representing 38% of all patients included in this meta-analysis), pancreatic cancer patients with a good PS appear to benefit from GEM-based cytotoxic combinations, whereas patients with a poor PS seem to have no survival benefit from combination chemotherapy.</p
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