Multifunctional Architectures Research Articles

Fluorescence in Nanobiotechnology: Sophisticated Fluorophores for Novel Applications

Nanobiotechnology is one of the fastest growing and broadest-ranged interdisciplinary subfields of the nanosciences. Countless hybrid bio-inorganic composites are currently being pursued for various uses, including sensors for medical and diagnostic applications, light- and energy-harvesting devices, along with multifunctional architectures for electronics and advanced drug-delivery. Although many disparate biological and nanoscale materials will ultimately be utilized as the functional building blocks to create these devices, a common element found among a large proportion is that they exert or interact with light. Clearly continuing development will rely heavily on incorporating many different types of fluorophores into these composite materials. This review covers the growing utility of different classes of fluorophores in nanobiotechnology, from both a photophysical and a chemical perspective. For each major structural or functional class of fluorescent probe, several representative applications are provided, and the necessary technological background for acquiring the desired nano-bioanalytical information are presented.

Reconfigurable Cooperative Intelligent Control Design for Space Missions

Space satellite network design and operation have become more challenging following emerging advanced applications and the increased number of satellites launched into the Earth orbit each year. This has also occasioned an obvious concern for space situational awareness management, interplanetary communications, post-launch reengineering and post-mission reapplications of spacecraft; these all require adaptive, reconfigurable and multifunctional space systems and networks. Enormous advances aimed at making spacecraft systems reconfigurable, reliable, broadband, and multifunctional have been patented. Consequently, recent space technology patents in reconfigurable and autonomous system designs and architectures have been studied and qualified. This paper presents a reconfigurable space satellite network design that uses cooperative space-borne systems to complement ground-based enhancements. Each network node employs the deterministic multifunctional architecture with packet router interface switch matrix platforms. The reconfigurable cooperative intelligent control (RCIC) design exploits the deterministic and reconfigurable property of field programmable gate array to offer in-situ autonomous control. Four reliable and adaptive space control capability modes have been identified for a robust space satellite network. Furthermore, the control capability has been analysed with recourse to satellite generations. Consequently, a case study reconfigurable space network covering femtosatellites to minisatellites has been designed. The analysis presented in this work promises to enhance small satellite formation and constellations designs and applications. It also enables real-time space surveillance and provides platforms for the reuse of decommissioned satellite systems.

A deterministic multifunctional architecture for highly adaptive small satellites

A deterministic multifunctional architecture design approach for a highly adaptive small satellite system is proposed in this paper. It enables five levels of design customisation of all categories of highly adaptive small satellites; adaptive functional modules implement higher-level customised and reconfigurable mission functions. Each adaptive multifunctional structural unit (AMSU) supports the subsystem functions as a ‘structural and functional block’ and comes either as a baseline or hybrid. Associated functional sub subsystem components are contained in each AMSU. This removes the conventional structural and functional subsystem boundaries. A meteorology spacecraft mission using a highly adaptive nanosatellite reveals, besides more advanced mission capabilities, 0.6 kg and 1 W mass- and power-savings respectively over a conventional nanosatellite system implementation. This novelty results in adaptive, reconfigurable and multifunctional architectures with economies of scale, timely launch, system-level reliability, flexible integration and test options, cost-effective mass production, post-mission reapplication and optimal performance at the desired mission objectives.

Multifunctional Dendritic Architectures: An Investigation of their Mechanical Properties

ABSTRACTThe paper deals with the synthesis and investigation of mechanical properties of multifunctional polyglycerol nanogels which consist of PEG with different chain lengths (glycerol, PEG 400, PEG 400-DGE, and PEG 1500). Their swelling behavior, elasticity, and stiffness are discussed in correlation with the PEG chain length. The nanogels built of PEG 400 exhibited most interesting and promising features and show the highest elasticity.

Encapsulation of Luminescent Silicon Nanocrystals within Mesoporous Silica Nanospheres: Synthesis and Effect on Photoluminescence

ABSTRACTSilicon nanocrystals (Si-NCs) are of significant research interest owing to their quantum confined photoluminescent (PL) properties and biological inertness. A promising application of these NCs is as the luminescent component in multifunctional biomedical technologies. In this report, we demonstrate the encapsulation of alkyl terminated Si-NCs within a mesoporous silica shell as a multifunctional imaging and drug delivery architecture. The Si-NC concentration was found to critically impact the nanoshell morphology. The impact of the encapsulation process on the Si-NC PL was studied, showing a blue-shift and decrease in intensity attributed to the oxidation of Si-NCs under basic conditions.

Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces

Among the many significant advances within the field of supramolecular chemistry over the past decades, the development of the so-called "dynamers" features a direct relevance to materials science. Defined as "combinatorial dynamic polymers", dynamers are constitutional dynamic systems and materials resulting from the application of the principles of supramolecular chemistry to polymer science. Like supramolecular materials in general, dynamers are reversible dynamic multifunctional architectures, capable of modifying their constitution by exchanging, recombining, incorporating components. They may exhibit a variety of novel properties and behave as adaptive materials. In this review we focus on the design of responsive switchable monolayers, i.e. monolayers capable to undergo significant changes in their physical or chemical properties as a result of external stimuli. Scanning tunneling microscopy studies provide direct evidence with a sub-nanometre resolution, on the formation and dynamic response of these self-assembled systems featuring controlled geometries and properties.

Periodic Wavelength-Arrangement-Based All-Optical Packet Switch

We conceptually propose and experimentally demonstrate a novel multifunction all-optical packet switch architecture with less active optical components and simpler traffic control by adopting a periodic wavelength arrangement between wideband fiber Bragg gratings and an arrayed waveguide grating in the optical buffering unit and output ports, respectively. Three functionalities of switch, including first-in-first-out multiplexing, switching, and add-drop are successfully exhibited by the proposed architecture with negligible power penalties.

ChemInform Abstract: Multifunctional Architectures Supported on Organostannoxane Scaffolds

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Multifunctional 3D nanoarchitectures for energy storage and conversion

The design and fabrication of three-dimensional multifunctional architectures from the appropriate nanoscale building blocks, including the strategic use of void space and deliberate disorder as design components, permits a re-examination of devices that produce or store energy as discussed in this critical review. The appropriate electronic, ionic, and electrochemical requirements for such devices may now be assembled into nanoarchitectures on the bench-top through the synthesis of low density, ultraporous nanoarchitectures that meld high surface area for heterogeneous reactions with a continuous, porous network for rapid molecular flux. Such nanoarchitectures amplify the nature of electrified interfaces and challenge the standard ways in which electrochemically active materials are both understood and used for energy storage. An architectural viewpoint provides a powerful metaphor to guide chemists and materials scientists in the design of energy-storing nanoarchitectures that depart from the hegemony of periodicity and order with the promise--and demonstration--of even higher performance (265 references).

Photodeposition of Pt on Colloidal CdS and CdSe/CdS Semiconductor Nanostructures

Photodeposition of Pt on Colloidal CdS and CdSe/CdS Semiconductor Nanostructures Gordana Dukovic, Maxwell G. Merkle, James H. Nelson, Steven M. Hughes, and A. Paul Alivisatos* Department of Chemistry, University of California, Berkeley and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Semiconductor photocatalysis has been identified as a promising avenue for the conversion of solar energy into environmentally friendly fuels, most notably by the production of hydrogen from water.[1–5] Nanometer-scale materials in particular have attracted considerable scientific attention as the building blocks for light-harvesting applications.[6,7] Their desirable attributes include tunability of the optical properties with size, amenability to relatively inexpensive low-temperature processing, and a high degree of synthetic sophistication leading to increasingly complex and multi-functional architectures. For photocatalysis in particular, the high surface- to- volume ratios in nanoscale materials should lead to an increased availability of carriers for redox reactions on the nanoparticle surface. Recombination of photoexcited carriers directly competes with photocatalytic activity.[3] Charge separation is often achieved with multi-component heterostructures. An early example is the case of TiO2 powders functionalized with Pt and RuO2 particles, where photoexcited electrons are transferred to Pt (the reduction site) and holes to RuO2 (the oxidation site).[8] More recently, many colloidally synthesized nanometer-scale metal–semiconductor heterostructures have been reported.[7,9,10] A majority of these structures are made by thermal methods.[7,10] We have chosen to study photochemical formation of metal–semiconductor heterostructures. The detailed understanding of the mechanisms involved in photodeposition of metals on nanometer-scale semiconductors is necessary to enable a high degree of synthetic control. At the same time, because the results of metal deposition can be directly observed by electron microscopy, it can be used to understand how factors such as nanocrystal composition, shape, carrier dynamics, and surface chemistry influence the photochemical properties of semiconductor nanocrystals. In this communication, we report on the photodeposition of Pt on colloidal CdS and CdSe/CdS core/shell nanocrystals. Among the II–VI semiconductors, CdS is of particular interest because it has the correct band alignment for water photolysis[2] and has been demonstrated to be photocatalytically active.[11–16] We have found that the photoexcitation of CdS and CdSe/CdS in the presence of an organometallic Pt precursor leads to deposition of Pt nanoparticles on the semiconductor surface. Stark differences are observed in the Pt nanoparticle location on the two substrates, and the photodeposition can be completely inhibited by the modification of the semiconductor surface. Our results suggest that tuning of the semiconductor band structure, spatial organization and surface chemistry should be crucial in the design of photocatalytic nanostructures.

Direct-digital RF-modulator: a multi-function architecture for a system-independent radio transmitter

The number of different radio systems is currently increasing in portable devices like mobile phones due to the wider range of applications that require an optimized wireless communications channel to different services or other devices. To make this cost and power efficient, the transmitter must be adaptable to several different radio systems while keeping the complexity and cost reasonable. This article presents fundamental circuit techniques to enable low cost, low power, and low complexity transmitter architecture by combining digital-to-analog conversion, up-conversion, unwanted sideband rejection, power control, and part of the digital image rejection filtering into a single mixed-signal circuit block. The direct-digital RF-modulator architecture is the basis for a software-defined radio transmitter. It was demonstrated against WCDMA system requirements, but the versatility and the performance of this architecture enables support for other radio systems, such as GPRS and WLAN.

Electrochemical Capacitors emPOWERING the 21st Century (Spring 2008)

Artist’s conception of a multifunctional electrode architecture for electrochemical capacitors in which nanoscopic manganese oxide deposits (green spheres) are distributed on a 3-dimensional, ultraporous, conductive carbon substrate (purple framework). Image generated by Michael S. Doescher (Naval Research Laboratory, 2004) using POV-RAY software, in support of the research programs of Jeffrey W. Long and Debra R. Rolison (Naval Research Laboratory).

Multi-functional architectures supported on organostannoxane scaffolds

Organostannoxane cages and aggregates of well-defined composition and structure can be prepared by the reactions of organotin oxides or organotin oxide-hydroxides with protic acids. The utility of this strategy for the preparation of dendrimer-like molecules containing a stannoxane core and a functional periphery is described.

Plasma within Templates: Molding Flexible Nanocrystal Solids into Multifunctional Architectures

Recently, there has been a great deal of progress in the synthesis of colloidal nanocrystals with tailored physical and chemical properties through control of size and shape, chemical composition, and surface functionalization (Alivisatos, A. P. Science 1996, 271 (5251), 933−937; Burda, C.; Chen, X. B.; Narayanan, R.; El-Sayed, M. A. Chem. Rev. 2005, 105 (4), 1025−1102). Nanocrystals are thus ideal building blocks for hierarchical self-assembly of topologically complex, multifunctional architectures with properties tuneable at each level of the hierarchy. Here, we present a method, which combines template-assisted self-assembly of nanocrystals with plasma polymerization (Cademartiri, L.; von Freymann, G.; Arsenault, A. C.; Bertolotti, J.; Wiersma, D. S.; Kitaev, V.; Ozin, G. A. Small 2005, 1 (12), 1184−1187) to realize hierarchical architectures that both retain the properties of the nanocrystals and offer multifunctionality. As examples, we describe CoFe2O4−PbS mixed nanocrystal nanorods, which photolumi...

Meet the Metamaterials

As research evolves, these unique composite materials will be fabricated with new, multifunctional architectures.

Molecular Tectonics on Surfaces: Bottom‐Up Fabrication of 1D Coordination Networks That Form 1D and 2D Arrays on Graphite

Nanopatterning of multifunctional architectures, that is, 1D or 2D arrays on surfaces, can be achieved through bottom-up fabrication of 1D coordination networks by self-assembly processes. A coordinating tecton bearing both monodentate and tridentate coordination poles is combined with suitable metal centers (see scanning tunneling microscopy image).

Multifunctional Nano-Architecture for Biomedical Applications

A multifunctional architecture for biomedical applications has been developed by deliberately combining the useful functions of superparamagnetism, luminescence, and surface functionality into one material. Good control of the core−shell architecture has been achieved by employing a sol−gel synthesis. Superparamagnetic iron oxide nanoparticles are first coated with silica to isolate the magnetic core from the surrounding. Subsequently, the dye molecules are doped inside a second silica shell to improve photostability and allow for versatile surface functionalities. The architecture has been characterized by transmission electron microscopy, UV−vis absorption and emission spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and magnetometry. The hybrid nanoparticles exhibit improved superparamagnetic behavior over the as-received nanoparticles with a significant decrease in the blocking temperature. The architecture shows emission properties similar to those of the free dye molecules, sug...

A method for designing high-radix multiplier-based processing units for multimedia applications

Multifunctional architecture for video and image processing (MAVIP) to be used in multimedia systems are proposed. MAVIP is a family of reconfigurable architectures derived from a single high-radix (4, 8, or 16) multiplier structure where: a) the list of potential partial products obtained at the first stage of multiplication may be reused; b) pipeline stages may be parallelised at different level to achieve required clock frequency and to improve balancing between these stages; and c) interconnections between the operational blocks may be multiplexed to make the structure multifunctional and to allow reusing basic multiplier blocks. The same device may operate either as a programmable processing unit with digital signal processor-specific operations or as a reconfigurable ASIC. Being small, MAVIP indicates competitive performance in video coding applications.

Multifunction architectures for RNS processors

Novel very large-scale integration architectures and a design methodology for adder-based residue number system (RNS) processors are presented in this paper. The new architectures compute residues for more than one modulus either serially or in parallel, while their use can increase the resource utilization in a processor. Complexity is reduced by sharing common intermediate results among the various RNS moduli channels and/or operations that compose an RNS processor. The presented architectures are distinguished into two subtypes, depending on whether the inter channel parallelism is preserved or not. The multifunction architecture paradigm is demonstrated by its application in residue multiplication, binary-to-residue conversion, quadratic RNS (QRNS) mapping, and base extension. The derived architectures are compared to previously reported equivalent ones and are found to be efficient in area/spl times/time product sense. Finally, the proposed design methodology reveals a new tradeoff in residue processor design, leading to more efficient RNS processors.