Modeling real-time communication systems: Practices and experiences in Motorola

Visual modeling languages and techniques have been increasingly adopted for software specification, design, development, and testing. With the major improvements of UML 2.0 and tools support, visual modeling technologies have significant potential for simplifying design, facilitating collaborations, and reducing development cost. In this paper, we describe our practices and experiences of applying visual modeling techniques to the design and development of real-time wireless communication systems within Motorola. A model-driven engineering approach of integrating visual modeling with development and validation is described. Results, issues, and our viewpoints are also discussed.     

Theranostic USPIO‐Loaded Microbubbles for Mediating and Monitoring Blood‐Brain Barrier Permeation

Efficient and safe drug delivery across the blood‐brain barrier (BBB) remains one of the major challenges of biomedical and (nano‐) pharmaceutical research. Here, it is demonstrated that poly(butyl cyanoacrylate)‐based microbubbles (MB), carrying ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles within their shell, can be used to mediate and monitor BBB permeation. Upon exposure to transcranial ultrasound pulses, USPIO‐MB are destroyed, resulting in acoustic forces inducing vessel permeability. At the same time, USPIO are released from the MB shell, they extravasate across the permeabilized BBB and they accumulate in extravascular brain tissue, thereby providing non‐invasive R ₂*‐based magnetic resonance imaging information on the extent of BBB opening. Quantitative changes in R ₂* relaxometry are in good agreement with 2D and 3D microscopy results on the extravascular deposition of the macromolecular model drug fluorescein isothiocyanate (FITC)‐dextran into the brain. Such theranostic materials and methods are considered to be useful for mediating and monitoring drug delivery across the BBB and for enabling safe and efficient treatment of CNS disorders.     

A comparison of dispersing media for various engineered carbon nanoparticles

Background  

With the increased manufacture and use of carbon nanoparticles (CNP) there has been increasing concern about the potential toxicity of fugitive CNP in the workplace and ambient environment. To address this matter a number of investigators have conducted in vitro and in vivo toxicity assessments. However, a variety of different approaches for suspension of these particles (culture media, Tween 80, dimethyl sulfoxide, phosphate-buffered saline, fetal calf serum, and others), and different sources of materials have generated potentially conflicting outcomes. The quality of the dispersion of nanoparticles is very dependent on the medium used to suspend them, and this then will most likely affect the biological outcomes.     

The in vivo effects of rhIL-1 alpha therapy on human monocyte activity

Pleiotropic cytokines such as interleukin-1 alpha (IL-1 alpha) have multiple effects on peripheral blood monocytes (PBMs). This study examined the ability of in vivo recombinant human IL-1 alpha (rhIL-1 alpha) therapy to enhance clinically important monocyte functions in ovarian cancer patients prior to chemotherapy. After 4 days of continuous infusion, in vivo rhIL-1 alpha therapy amplified both the number and activity of PBMs. Therapy with rhIL-1 alpha increased the number of PBMs sixfold. These monocytes had a significantly increased ability to produce superoxide anion in response to phorbol 12,13-dibutyrate stimulation. Their ability to secrete spontaneously the immunomodulatory cytokines IL-1 alpha and IL-1 beta was significantly increased, but their ability to secrete tumor necrosis factor alpha (TNF-alpha) was not significantly elevated. These effects of rhIL-1 alpha infusion on cytokine secretion by PBMs appear to be related to rhIL-1 alpha-induced increases in the mRNA levels for these cytokines. In contrast, rhIL-1 alpha therapy did not significantly alter PBM response to lipopolysaccharide (10 micrograms/ml). In summary, infused rhIL-1 alpha, in addition to its use as a myeloprotective agent, has enhancing effects on the number and activity of PBMs. The effects of rhIL-1 alpha infusion on PBM function demonstrated here should at least transiently increase the ability of monocytes to combat infection and enhance host immune response.     

Van der Waals SnSe2(1−x)S2x Alloys: Composition‐Dependent Bowing Coefficient and Electron–Phonon Interaction

The design of advanced functional materials with customized properties often requires the use of an alloy. This approach has been used for decades, but only recently to create van der Waals (vdW) alloys for applications in electronics, optoelectronics, and thermoelectrics. A route to engineering their physical properties is by mixing isoelectronic elements, as done for the SnSe_2(1?x)S_2x alloy. Here, by experiment and first‐principles modeling, it is shown that the value of x can be adjusted over a wide range, indicating good miscibility of the SnS₂ and SnSe₂ compounds. The x‐dependence of the indirect bandgap energy from E_ind = 1.20 eV for SnSe₂ to E_ind = 2.14 eV for SnS₂, corresponds to a large bowing coefficient b ≈ 1 eV, arising from volume deformation and charge exchange effects due to the different sizes and orbital energies of the S‐ and Se‐atoms. This also causes composition‐dependent phonon energy modes, electron–phonon interaction, and temperature dependence of E_ind. The alloys are exfoliable into thin layers with properties that depend on the composition, but only weakly on the layer thickness. This work shows that the electronic and vibrational properties of the SnSe_2(1?x)S_2x alloy and its thin layers provide a versatile platform for development and exploitation.     

Design and preparation of novel Diels–Alder crosslinking polymer and its application in NLO materials

Principally novel crosslinking nonlinear optical and optoelectronics system based on Diels–Alder reaction was designed. The copolymer of methyl methacrylate and anthracen-9-ylmethyl methacrylate (PMMA-AMA) was used as a host polymer; chromophore ETO was used as guest chromophore; chromophore ETO and N,N-(methylenediphenyl)bismaleimide were used as crosslinker. The thermodynamic property of crosslinking system studied by differential scanning calorimeter (DSC) showed us that the glass transition temperature was about 65?°C and the crosslinking temperature was varied between 80 and 120?°C The crosslinking reactive speed and effectiveness were studied by ultraviolet absorption and infrared absorption spectroscopy with spectral resoluiotn 1 cm^?1. These results have indicated that the cross linking process could be finished at 110?°C for 20 min. Surprisingly, such EO polymer showed us a large EO coefficient of about 96.3 pm/V at wavelength 1 µm and excellent long term stability about 85% with respect to its initial value and can be kept after 250 h of heating at 80?°C.