Multifunctional Magnetic Optical Sensor Particles with Tunable Sizes for Monitoring Metabolic Parameters and as a Basis for Nanotherapeutics

Magnetic optical sensor particles with multifunctional cores and shells are synthesized via a facile nanoprecipitation method and the subsequent modification of the particle shell. The hydrophobic particle core includes optical oxygen indicators, a light harvesting system, photosensitizers, and magnetic nanoparticles. Further functionalities are introduced by modifying the shell with enzymes, antibodies, multiple layers of polyelectrolytes, stimuli‐responsive polymers, and luminescent indicator dyes. The hydrodynamic diameter is tunable by varying different precipitation parameters.     

Comment on `Nonplanar VLSI arrays with high fault-tolerancecapabilities'

In the above-named work (see ibid., vol.38, p.51-7, April 1989), S. Lafiti and A. El-Amawy apply, in a straightforward manner, the method developed by A.D. Singh (1985) to calculate lower bounds for the yield of nonplanar interstitial redundancy topologies of processor arrays with spare processors. In their introduction, they claim that the models suggested by I. Koren and D.K. Pradhan (1987) are highly theoretical since the number of states in the Markov model might be very large and the determination of the transition rates might be intractable. They add that applying some empirical rules, as suggested by Koren and Pradhan (1987), can lead to unrealistic results and may require a large number of computations. They also claim that the model of Koren and Pradhan does not suggest an algorithm to replace faulty elements. They conclude that a simpler model, like the one proposed by Singh, is needed for calculating the yield of fault-tolerant processor arrays. In the present comment, Koren and Pradhan respond to the above comments and attempt to clarify the differences between their yield analysis and that of Singh     

High-frequency InGaAs/InP multiple-quantum-well buried-mesa electroabsorption optical modulator

We describe the structure and performance characteristics of an InGaAs/InP multiple-quantum-well (MQW) electro-absorption buried-mesa optical modulator. The device is fabricated with two metal-organic chemical-vapour-deposition (MOCVD) growth steps, wherein small-area circular (40?m diameter) PIN diodes are buried with Fe-doped semiinsulating (SI) InP regrowth. The modulator has a relatively low insertion loss (4.5 dB) with 25% modulation depth and very high modulation bandwith (5.3 GHz) operating at 1.62?m wavelength.     

Scalable reconfigurable equipment design principles

Scalability is one of six key characteristics found in reconfigurable manufacturing systems. Scalable systems satisfy changing capacity requirements efficiently through system reconfiguration, and in the flexible manufacturing literature this capability is called expansion flexibility. The development of modular scalable machine tools is a necessary precursor to achieving scalable systems. Unfortunately, there is little work describing the design of scalable machines. This paper establishes the need for scalable machines and a basis for evaluating and describing them. Applicable metrics are defined, and an architecture for scalable machines is presented. Two examples illustrate the scalable architecture. Finally, a design parameter based on a mathematical approach is presented to determine the optimal number of modules to be included on a modular scalable machine. This as a design parameter is important because it limits machine size and the number of module interfaces included in the base machine structure.     

Regulating the temperature regime of water in the lower pool of a hydroelectric station

Conclusions An analysis showed that the water intakes for selective withdrawal of water from a reservoir for water-supply purposes known from the scientific and technical literature cannot be used effectively for withdrawing a large quantity of water for hydrostation turbines, and the known intakes for selective withdrawal of a large quantity of water have substantial shortcomings and are in need of further design improvement. Simultaneously with this, the conclusions of the 1993 Divnogorsk conference that at present “it is impossible to freeze the Yenisei River within the Krasnoyarsk city limits” for a number of reasons is confirmed. However, under more favorable conditions than the Krasnoyarsk hydrostation, the selective withdrawal of water from a deepwater intake for hydrostation turbines, despite the high additional expenditures, can be justified and necessary. The proposed design of a floating intake of an electric power station has a number of advantages compared with the known floating intakes. In this case it recommended to direct the water that is withdrawn from the surface layer of the reservoir and passed only through one or two turbines to save expenditures to the bank part of the river, which promotes in the lower pool the formation of ice near the river banks and in its branches in the winter and their “warming” in the summer. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, pp. 46–49, September, 1997.     

Balanced operation of a GaInAs/GaInAsP multiple-quantum-wellintegrated heterodyne receiver

The balanced operation of a multiple-quantum-well balanced heterodyne receiver photonic integrated circuit (PIC) is described. Using only SMA-connected 50 Ω commercial electronics, a free-space beam sensitivity of -42.3 dBm at 108 Mb/s and -39.7 dBm at 200 Mb/s for NRZ FSK (frequency-shift keying) reception has been achieved. This represents a 14 dB improvement over any previous heterodyne receiver PIC sensitivity. In addition to providing the multichannel benefits of heterodyne reception, this is also the highest sensitivity yet reported for any OEIC (optoelectronic integrated circuit) receiver     

Operation of integrated InGaAsP-InP optical amplifier-monitoringdetector with feedback control circuit

Monolithic integration of a monitoring detector with an optical amplifier simplifies the use of an amplifier in lightwave systems. The structure and performance are described of a monolithically integrated semiconductor optical amplifier with low-loss Y-branching waveguides and a monitoring p-i-n detector. The photocurrent of the integrated detector can be used as a single control parameter for amplifier output leveling, gain optimization, and in situ monitoring of facet antireflective coatings     

System-level power-aware design techniques in real-time systems

Power and energy consumption has recently become an important issue and consequently, power-aware techniques are being devised at all levels of system design; from the circuit and device level, to the architectural, compiler, operating system, and networking layers. In this paper, we concentrate on power-aware design techniques for real-time systems. While the main focus is on hard real-time, soft real-time systems are considered as well. We start with the motivation for focusing on these systems and provide a brief discussion on power and energy objectives. We then follow with a survey of current research on a layer-by-layer basis. We conclude with illustrative examples and open research challenges. This paper provides an overview of power-aware techniques for the real-time system engineer as well as an up-to-date reference list for the researcher.     

Fault-sensitivity analysis and reliability enhancement of analog-to-digital converters

Reliability of systems used in space, avionic, and biomedical applications is highly critical. Such systems consist of an analog front-end to collect data, an analog-to-digital converter (ADC) to convert the collected data to digital form, and a digital unit to process it. Though a considerable amount of research has been performed to increase the reliability of digital blocks, the same cannot be claimed for mixed-signal blocks. The reliability enhancement that we employ begins with fault-sensitivity analysis followed by redesign. The data obtained from the sensitivity analysis is used to grade blocks based on their sensitivity to faults. The highly sensitive blocks can then be replaced by more reliable alternatives. The improvement gained by opting for more robust implementations might be limited due to the number of possible implementations. In these cases, alternative reliability enhancement techniques such as adding redundancy may provide further improvements. The steps involved in the reliability enhancement of ADCs are illustrated in this paper by first proposing a sensitivity analysis methodology for /spl alpha/-particle induced transients and then suggesting redesign techniques to improve the reliability of the ADC. A novel concept of node weights specific to /spl alpha/-particle transients is introduced, which improves the accuracy of the sensitivity analysis. The fault simulations show that, using techniques such as alternative robust implementations, adding redundancy, pattern detection, and transistor sizing, considerable improvements in reliability can be attained.