UMTS radio-over-fiber pico-cell interconnection employing uncooled DFB lasers for multi-mode fibre modulation bandwidth enhancement

This paper analyzes experimentally the use of distributed feedback lasers (DFB) in order to increase modulation bandwidth in multimode fibres, enabling 3 km bidirectional radio-over-multimode fibre UMTS transmission in a frequency-division duplexing (FDD) configuration

Adam Smith goes mobile : managing services beyond 3G with the digital marketplace

The next generation of mobile communications systems is expected to offer new business opportunities to existing and new market players. A market-based middleware framework has been recently proposed whereby service providers, independent of network operators, are able to tender online service contracts to network operators in a dynamic and competitive manner. This facilitates a seamless service provision over disparate networks in a consumer-centric manner. Service providers select network bearers according to the network operators' ability to meet the QoS target, which in turn is influenced, among other things, by user's price and quality requirements. The benefits of this proposal are the complementarity of numerous network resources, the decoupling of services and networks in a self-organising distributed environment, and increased competition to consumers’ advantag

THz in biology and medicine: toward quantifying and understanding the interaction of millimeter- and submillimeter-waves with cells and cell processes

As the application and commercial use of millimeter- and submillimeter-wavelength radiation become more widespread, there is a growing need to understand and quantify both the coupling mechanisms and the impact of this long wavelength energy on biological function. Independent of the health impact of high doses of radio frequency (RF) energy on full organisms, which has been extensively investigated, there exists the potential for more subtle effects, which can best be quantified in studies which examine real-time changes in cellular functions as RF energy is applied. In this paper we present the first real time examination of RF induced changes in cellular activity at absorbed power levels well below the existing safe exposure limits. Fluorescence microscopy imaging of immortalized epithelial and neuronal cells in vitro indicate increased cellular membrane permeability and nanoporation after short term exposure to modest levels (10-50 mW/cm2) of RF power at 60 GHz. Sensitive patch clamp measurements on pyramidal neurons in cortical slices of neonatal rats showed a dramatic increase in cellular membrane permeability resulting either in suppression or facilitation of neuronal activity during exposure to sub-μW/cm2 of RF power at 60 GHz. Non-invasive modulation of neuronal activity could prove useful in a variety of health applications from suppression of peripheral neuropathic pain to treatment of central neurological disorders

Multifunctional photonic integrated circuit for diverse microwave signal generation, transmission and processing

Microwave photonics (MWP) studies the interaction between microwave and optical waves for the generation, transmission and processing of microwave signals (i.e., three key domains), taking advantages of broad bandwidth and low loss offered by modern photonics. Integrated MWP using photonic integrated circuits (PICs) can reach a compact, reliable and green implementation. Most PICs, however, are recently developed to perform one or more functions restricted inside a single domain. In this paper, as highly desired, a multifunctional PIC is proposed to cover the three key domains. The PIC is fabricated on InP platform by monolithically integrating four laser diodes and two modulators. Using the multifunctional PIC, seven fundamental functions across microwave signal generation, transmission and processing are demonstrated experimentally. Outdoor field trials for electromagnetic environment surveillance along an in-service high-speed railway are also performed. The success to such a PIC marks a key step forward for practical and massive MWP implementations.Comment: 17 page

Integrated Transversal Equalizers in High-Speed Fiber-Optic Systems

Intersymbol interference (ISI) caused by intermodal dispersion in multimode fibers is the major limiting factor in the achievable data rate or transmission distance in high-speed multimode fiber-optic links for local area networks applications. Compared with optical-domain and other electrical-domain dispersion compensation methods, equalization with transversal filters based on distributed circuit techniques presents a cost-effective and low-power solution. The design of integrated distributed transversal equalizers is described in detail with focus on delay lines and gain stages. This seven-tap distributed transversal equalizer prototype has been implemented in a commercial 0.18-µm SiGe BiCMOS process for 10-Gb/s multimode fiber-optic links. A seven-tap distributed transversal equalizer reduces the ISI of a 10-Gb/s signal after 800 m of 50-µm multimode fiber from 5 to 1.38 dB, and improves the bit-error rate from about 10^-5 to less than 10^-12

Thermal Monitoring: Raman Spectrometer System for Remote Measurement of Cellular Temperature on a Microscopic Scale

A simple setup was demonstrated for remote temperature monitoring of water, water-based media, and cells on a microscopic scale. The technique relies on recording changes in the shape of a stretching band of the hydroxyl group in liquid water at 3,100-3,700 cm^(-1). Rather than direct measurements in the near-infrared (IR), a simple Raman spectrometer setup was realized. The measured Raman shifts were observed at near optical wavelengths using an inverted microscope with standard objectives in contrast to costly near-IR elements. This allowed for simultaneous visible inspection through the same optical path. An inexpensive 671-nm diode pump laser (<100 mW), standard dichroic and lowpass filters, and a commercial 600-1,000 nm spectrometer complete the instrument

Multimodality imaging in vivo for preclinical assessment of tumor-targeted doxorubicin nanoparticles.

This study presents a new multimodal imaging approach that includes high-frequency ultrasound, fluorescence intensity, confocal, and spectral imaging to improve the preclinical evaluation of new therapeutics in vivo. Here we use this approach to assess in vivo the therapeutic efficacy of the novel chemotherapy construct, HerDox during and after treatment. HerDox is comprised of doxorubicin non-covalently assembled in a viral-like particle targeted to HER2+ tumor cells, causing tumor cell death at over 10-fold lower dose compared to the untargeted drug, while sparing the heart. Whereas our initial proof-of-principle studies on HerDox used tumor growth/shrinkage rates as a measure of therapeutic efficacy, here we show that multimodal imaging deployed during and after treatment can supplement traditional modes of tumor monitoring to further characterize the particle in tissues of treated mice. Specifically, we show here that tumor cell apoptosis elicited by HerDox can be monitored in vivo during treatment using high frequency ultrasound imaging, while in situ confocal imaging of excised tumors shows that HerDox indeed penetrated tumor tissue and can be detected at the subcellular level, including in the nucleus, via Dox fluorescence. In addition, ratiometric spectral imaging of the same tumor tissue enables quantitative discrimination of HerDox fluorescence from autofluorescence in situ. In contrast to standard approaches of preclinical assessment, this new method provides multiple/complementary information that may shorten the time required for initial evaluation of in vivo efficacy, thus potentially reducing the time and cost for translating new drug molecules into the clinic