Expression of platelet-derived growth factor (PDGF)-A, PDGF-B and the PDGF-alpha receptor, but not the PDGF-beta receptor, in human malignant melanoma in vivo

There has been considerable interest in the potential role of growth factors in the initiation and development of cutaneous malignant melanoma (CMM). Platelet-derived growth factor (PDGF) has been shown to be secreted by melanoma cell lines and by metastatic melanoma in vivo. PDGF also has been reported to stimulate the development of tumour stroma and new blood vessels. We studied the expression of PDGF and its receptors by both immunohistochemistry (IHC) and in situ hybridization (ISH) in primary and metastatic melanoma and in normal skin specimens. Cryostat sections were incubated with 35S-labelled riboprobes and antibodies for PDGF-AA, PDGF-alpha receptor, PDGF-BB and PDGF-beta receptor. Both primary and metastatic melanoma exhibited significant expression of PDGF-AA, PDGF-BB and PDGF-alpha receptor by both IHC and ISH, compared with only background expression in normal skin. We did not observe expression of PDGF-beta receptor in melanoma. Our results suggest that PDGF may function as an autocrine growth factor, as well as an angiogenesis factor, in CMM tumour development. This expression of the PDGF-alpha receptor rather than the beta receptor may be unique among solid tumours.     

Solvothermal synthesis,nanostructural characterization and gas cryo-adsorption studies in a metal–organic framework (IRMOF-1) material

A nanoporous metal–organic framework material, exhibiting an IRMOF-1 type crystalline structure, was prepared by following a direct solvothermal synthesis approach, using zinc nitrate and terephthalic acid as precursors and dimethylformamide as solvent, combined with supercritical CO₂ activation and vacuum outgassing procedures. A series of advanced characterization methods were employed, including scanning electron microscopy, Fourier-transform infrared radiation spectroscopy and X-ray diffraction, in order to study the morphology, surface chemistry and structure of the IRMOF-1 material directly upon its synthesis. Porosity properties, such as Brunauer–Emmet–Teller (BET) specific area (～520 m²/g) and micropore volume (～0.2 cm³/g), were calculated for the activated sample based on N₂ gas sorption data collected at 77 K. The H₂ storage performance was preliminary assessed by low-pressure (0–1 bar) H₂ gas adsorption and desorption measurements at 77 K. The activated IRMOF-1 material of this study demonstrated a fully reversible H₂ sorption behavior combined with an adequate gravimetric H₂ uptake relative to its BET specific area, thus achieving a value of ～1 wt.% under close-to-atmospheric pressure conditions.     

Dextran-coated gold nanoparticles for the assessment of antimicrobial susceptibility

Bacteria rapidly evolve mechanisms to become resistant to antibiotics. Therefore, identifying an effective antibiotic or antibacterial agent and administering it at concentrations that will successfully prevent bacterial growth (antimicrobial susceptibility) is critical for health care decision making and vital for the battle against multi-drug-resistant bacteria. Currently, the determination of antimicrobial susceptibility requires at least 24 h. Herein, we describe a nanoparticle-based antimicrobial susceptibility assay based on the concanavalin A-induced clustering of dextran-coated gold nanoparticles, which sense the presence of available complex carbohydrates in bacterial suspension. Under conditions of bacterial growth inhibition, addition of concanavalin A results in the formation of extensive dextran gold nanoassemblies, which are facilitated by the presence of free carbohydrates in solution and result in large shifts in the surface plasmon band of the nanoparticles. Meanwhile, at conditions of increased bacterial growth, a decrease in the amount of free carbohydrates in solution will occur due to an increased carbohydrate uptake by the proliferating bacteria. This will result in a decrease in the size of the gold nanoparticle clusters and an increase in the number of nanoparticles that bind to bacterial surface carbohydrates, causing lower shifts in the plasmonic band. The gold nanoparticle-based assessment of antimicrobial susceptibility yields results within 3 h and can be used for the high-throughput screening of samples during epidemics and identification of potential antimicrobial agents to expedite clinical decision-making in point-of-care diagnostics.     

Crystallization of amorphous silicon thin films: comparison between experimental and computer simulation results

Polycrystalline silicon obtained by the crystallization of thin amorphous silicon films has been an important material for microelectronics technology during the last decades. Many properties are improved in crystallized amorphous silicon compared to the as-deposited polysilicon such as larger grain size, smoother surface, and higher-carrier mobility. In this work, the crystallization of amorphous silicon is investigated by combining transmission electron microscopy (TEM) observations and molecular dynamics calculations. TEM observations on a series of specimens have shown that the majority of the silicon grains are oriented with a zone axis normal to the surface. In order to understand the crystallization mechanism molecular dynamic simulations were performed. It is found that the c/amorphous interface exhibits the lowest reduced interfacial energy density while the c/amorphous has the lowest reduced energy differences per unit interfacial area. The most energetically unfavorable interface is c/amorphous.     

Antenna applications of negative-refractive-index transmission-line structures

A number of new antenna-related applications that have recently been developed at the University of Toronto based on the concept of negative-refractive-index transmission-line metamaterials are reviewed. These include non-radiating phase-shifting lines that can produce either a positive or a negative phase-shift while exhibiting a broadband linear phase response, as well as compact and broadband series power dividers and associated planar series-fed printed dipole arrays with reduced beam-squinting. Moreover, a fully printed electrically small ring antenna featuring vertical polarisation and good radiation efficiency is also described     

Drug/Dye‐Loaded,Multifunctional Iron Oxide Nanoparticles for Combined Targeted Cancer Therapy and Dual Optical/Magnetic Resonance Imaging

A biocompatible, multimodal, and theranostic functional iron oxide nanoparticle is synthesized using a novel water‐based method and exerts excellent properties for targeted cancer therapy, and optical and magnetic resonance imaging. For the first time, a facile, modified solvent diffusion method is used for the co‐encapsulation of both an anticancer drug and near‐infrared dyes. The resulting folate‐derivatized theranostics nanoparticles could allow for targeted optical/magnetic resonance imaging and targeted killing of folate‐expressing cancer cells.     

Atypical p38 Signaling,Activation, and Implications for Disease

The mitogen-activated protein kinase (MAPK) p38 is an essential family of kinases, regulating responses to environmental stress and inflammation. There is an ever-increasing plethora of physiological and pathophysiological conditions attributed to p38 activity, ranging from cell division and embryonic development to the control of a multitude of diseases including retinal, cardiovascular, and neurodegenerative diseases, diabetes, and cancer. Despite the decades of intense investigation, a viable therapeutic approach to disrupt p38 signaling remains elusive. A growing body of evidence supports the pathological significance of an understudied atypical p38 signaling pathway. Atypical p38 signaling is driven by a direct interaction between the adaptor protein TAB1 and p38α, driving p38 autophosphorylation independent from the classical MKK3 and MKK6 pathways. Unlike the classical MKK3/6 signaling pathway, atypical signaling is selective for just p38α, and at present has only been characterized during pathophysiological stimulation. Recent studies have linked atypical signaling to dermal and vascular inflammation, myocardial ischemia, cancer metastasis, diabetes, complications during pregnancy, and bacterial and viral infections. Additional studies are required to fully understand how, when, where, and why atypical p38 signaling is induced. Furthermore, the development of selective TAB1-p38 inhibitors represents an exciting new opportunity to selectively inhibit pathological p38 signaling in a wide array of diseases.     

Matrix hybridization in the interlayer for carbon fiber reinforced composites

Polymeric composites have gone through a level of maturity beyond the laboratory stage with the development of the Boeing 787, the structure of which contains more than 50% composites. Nonetheless, a basic understanding of the material used in its primary structure has not been extensively investigated. For instance, micromechanical models are inadequate as they always assume an evenly distributed homogeneous matrix, without following classic lamination theory, which assumes constant stress through the laminate thickness. Our program now in its third year at the Polymeric Composites Laboratory in Seattle, supported by industry as well as government agencies, and in collaboration with several universities on a global scale, is developing such concepts for understanding and improving matrices in layered configurations. This effort focuses on the development of interlayer systems used as enablers to improve certain properties of the composite, such as fracture‐toughness and crack‐propagation inhibition. POLYM. COMPOS., 31:1965–1976, 2010. © 2010 Society of Plastics Engineers.     

Photorealistic Large-Scale Urban City Model Reconstruction

The rapid and efficient creation of virtual environments has become a crucial part of virtual reality applications. In particular, civil and defense applications often require and employ detailed models of operations areas for training, simulations of different scenarios, planning for natural or man-made events, monitoring, surveillance, games, and films. A realistic representation of the large-scale environments is therefore imperative for the success of such applications since it increases the immersive experience of its users and helps reduce the difference between physical and virtual reality. However, the task of creating such large-scale virtual environments still remains a time-consuming and manual work. In this work, we propose a novel method for the rapid reconstruction of photorealistic large-scale virtual environments. First, a novel, extendible, parameterized geometric primitive is presented for the automatic building identification and reconstruction of building structures. In addition, buildings with complex roofs containing complex linear and nonlinear surfaces are reconstructed interactively using a linear polygonal and a nonlinear primitive, respectively. Second, we present a rendering pipeline for the composition of photorealistic textures, which unlike existing techniques, can recover missing or occluded texture information by integrating multiple information captured from different optical sensors (ground, aerial, and satellite).