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A simple and facile stereolithography 3D printing technique was utilized to fabricate piezoelectric photopolymer-based polyvinylidene fluoride (PVDF) blends. Different process variables, such as solvent (N,N-dimethylformamide, DMF) to PVDF ratio and PVDF solution to photopolymer resin (PR) ratio, were engineered to enhance the dispersion of the PVDF into the PR so as to achieve the maximum piezoelectric coupling coefficient. Our results demonstrate that a ratio of 1:10 (PVDF:DMF) and 2 wt%-PVDF/PR was optimal for the best dissolution of the PVDF, 3D printability, and piezoelectric properties. Under these conditions, the blend generated ±0.121 nA under 80 N dynamic loading excitation. We believe that the findings of this work would promote many further studies on the mass production of flexible piezoelectric polymer blends with higher quality finished surface and design flexibility.

Segmentation of the lung field is considered as the first and crucial stage in diagnosis of pulmonary diseases. In clinical practice, computer-aided systems are used to segment the lung region from chest X-ray (CXR) or CT images. The task of segmentation is challenging due to the presence of opacities or consolidation in CXR, which are typically produced by overlaps between the lung region and intense abnormalities caused by pulmonary diseases such as pneumonia, tuberculosis, or COVID-19. Recently, Convolution Neural Networks (CNNs) have been shown promising for segmentation and detection in digital images. In this paper, we propose a two-stage framework based on adapted U-Net architecture to leverage automatic lung segmentation. In the first stage, we extract CXR-patches and train a modified U-Net architecture to generate an initial segmentation of lung field. The second stage is the post-processing step, where we deploy image processing techniques to obtain a clear final segmentation. The performance of the proposed method is evaluated on a set of 138 CXR images obtained from Montgomery County’s Tuberculosis Control Program, producing an average Dice Coefficient (DC) of 94.21%, and an average Intersection-Over-Union (IoU) of 91.37%.

Multiwall carbon nanotubes (MWCNTs) are utilized to resolve low coupling coefficient issue by dispersing MWCNTs in poly(vinylidene fluoride) matrix to create stress reinforcing network, dispersant, and electron conducting functions for barium titanate (BT) nanoparticles. Various BT and MWCNT percentages of nanocomposite film are fabricated by FDM three-dimensional (3D) printing which can simplify the fabrication process as well as lower cost and design flexibility. Increasing MWCNTs and BT particles gradually increase piezoelectric coefficient (d31) by 0.13 pC/N with 0.4 wt%-MWCNTs/18 wt%-BT. These results provide not only a technique to print piezoelectric nanocomposites but also unique materials combination for sensor application.

Infection during pregnancy is common and the developing fetal brain is vulnerable to vertical transmission due to immaturity of the fetal immune system. Infection is a major cause of multiple organ abnormalities, including the neuraxis, due to the neurotropism of the infectious agents. This review sets out to give an overview of fetal infection, review the general principles of the nature and timing of the infectious insult with respect to outcomes, review the neuroimaging of infection by ultrasound and magnetic resonance imaging (MRI), and review the various pathogens involved, including the two most common, cytomegalovirus (CMV) and Toxoplasma, and also other common viral and nonviral infections.

This study investigates the removal efficiency of disinfection by-products (DBPs) in raw water at a water treatment plant using a biological powder-activated carbon system (BPACS). The presence of an excessive amount of DBPs has a large impact on the water quality of drinking water treated from the purification process. This study collected rapidly filtered water from an advanced water treatment plant for use in experiments on raw water. The removal efficiency of the trihalomethane formation potential (THMFP) and haloacetic acids formation potential (HAAFP) was studied under various hydraulic retention times and under organic DOC loadings. The results showed that the BPACS lowered the average concentration of dissolved organic carbon (DOC), UV(254) and the SUVA value (equivalent to UV(254)/DOC) in raw water. The system efficiently removed the THMFP and HAAFP during the treatment of the three primary organic carbon items. These results highlight the importance of the BPACS for efficiently treating disinfection by-products. These discoveries provide important information on biological degradation behaviors that can remove excessive amounts of disinfection by-products from drinking water.

The observed initial gain degradation of AlGaAs/GaAs heterojunction bipolar transistors under current stress was investigated. The change in device characteristics is attributed to a dissociation of passivating hydrogen in the base layer during stress. The hydrogen passivation occurs during the implant isolation process. An activation energy of 0.75 eV was measured for the junction temperature dependence of the dissociation process.

This study focused on reducing the haloacetic acid (HAA) concentrations in treated drinking water. HAA has been thought to be one possible nutrient supporting heterotrophic bacteria regrowth in drinking water. In this study, experiments were conducted using a pilot-scale system to evaluate the efficiency of biological filters (BF) for reducing excess HAA concentrations in water. The BF system reduced the total HAA concentration and the concentrations of five HAA species in the water. Dichloroacetic acid (DCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA) were the three main HAA5 species that were present in the treated drinking water in this investigation. Combined, these three species represent approximately 77% of the HAA5 in the finished water after BF. The verification of the empirical HAA equation for the outlet in the BF system indicated linear relationships with high correlation coefficients. The empirical equation for the HAA5 concentrations in the finished water was established by examining other nutrients (e.g., dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm wavelength (UV254), and ammonia nitrogen) that can reduce pathogenic contamination. These findings may be useful for designing advanced processes for conventional water treatment plants or for managing water treatment and distribution systems for providing high-quality drinking water.

We present a single-chip asynchronous multiprocessor optoelectronic bit-sliced arrayed (AMOEBA) crossbar switch. The AMOEBA switch addresses the challenge to produce a large-scale, nonblocking packet switch through dense integration of photonic devices directly onto silicon VLSI circuits. Optoelectronic-VLSI technology is used to integrate the switch fabric, routing controller, packet buffers, line interface circuits, and optoelectronic conversion devices on a single chip. We show how free-space optical interconnects and wavelength-and-space-division-multiplex networking on single-mode fibers can provide switched interconnection between multiple nodes in a distributed computing environment. An optomechanical transceiver package accomplishes the free-space-to-fiber interfacing. We report the implementation and testing of the key components of a 16-channel AMOEBA prototype switch with a potential capacity of 12.8 Gb/s (or 800 Mb/s/channel), and capable of switching 16 million packets per second.

Using the next-to-leading order QCD-corrected effective Hamiltonian, charmless exclusive nonleptonic decays of the $B_s$ meson into $\eta$ or $\eta'$ are calculated within the generalized factorization approach. Nonfactorizable contributions, which can be parametrized in terms of the effective number of colors $N_c^{\rm eff}$ for $P P$ and $V P$ decay modes, are studied in two different schemes: (i) the one with the "homogeneous" structure in which $(N_c^{\rm eff})_1 \approx (N_c^{\rm eff})_2 \approx ... \approx (N_c^{\rm eff})_{10}$ is assumed, and (ii) the "heterogeneous" one in which the possibility of $N_c^{\rm eff}(V+A) \neq N_c^{\rm eff}(V-A)$ is considered, where $N_c^{\rm eff}(V+A)$ denotes the effective value of colors for the $(V-A)(V+A)$ penguin operators and $N_c^{\rm eff}(V-A)$ for the $(V-A)(V-A)$ ones. For processes depending on the $N_c^{\rm eff}$-stable $a_i$ such as $\bar{B_s} \to (\pi,\rho) (\eta^{'},\eta)$, the predicted branching ratios are not sensitive to the factorization approach we choose. While for the processes depending on the $N_c^{\rm eff}$-sensitive $a_i$ such as $\bar{B_s} \to \omega \eta^{(')}$, there is a wide range for the branching ratios depending on the choice of the $N_c^{\rm eff}$ involved. We have included the QCD anomaly effect in our calculations and found that it is important for $\bar{B_s} \to \eta^{(')} \eta^{(')}$. The effect of the $(c\bar c) \to \eta'$ mechanism is found to be tiny due to a possible CKM-suppression and the suppression in the decay constants except for the $\bar{B_s} \to \phi \eta$ decay within the "naive" factorization approach, where the internal $W$ diagram is CKM-suppressed and the penguin contributions are compensated., Comment: 13 pages

The experimental hint of large $B\to \eta^\prime + X_s$ is linked to the $b\to s$ penguins via the gluon anomaly. Using running $\alpha_s$ in the $\eta^\prime$-$g$-$g$ coupling, the standard $b\to sg^*$ penguin alone seems insufficient, calling for the need of dipole $b\to sg$ at 10% level from new physics, which could also resolve the ${\cal B}_{s.l.}$ and charm counting problems. The intereference of standard and new physics contributions may result in direct CP asymmetries at 10% level, which could be observed soon at B Factories.

We include nonfactorizable soft gluon corrections into the perturbative QCD formalism for exclusive nonleptonic heavy meson decays, which combines factorization theorems and effective field theory. These corrections are classified according to their color structures, and exponentiated separately to complete the Sudakov resummation up to next-to-leading logarithms. The nonfactorizable contributions in nonleptonic decays are clearly identified in our formalism, and found to be positive for bottom decays and negative for charm decays. Our analysis confirms that the large-$N_c$ approximaton is applicable to charm decays, but not to bottom decays, consistent with the phenomenological implications of experimental data. The comparision of our predictions with those from QCD sum rules is also made., Comment: 21 pages, LaTeX

Exclusive charmless B decays to $\eta'$ and $\eta$ are studied in the standard effective Hamiltonian approach. The effective coefficients that take into account nonfactorizable effects in external and internal W-emission amplitudes are fixed by experiment. Factorization is applied to the matrix elements of QCD, electroweak penguin operators and next-to-leading corrections to penguin Wilson coefficients, which are renormalization-scheme dependent, are included, but the resultant amplitude is renormalization-scheme and -scale independent. We show that the unexpectedly large branching ratio of $B^\pm\to \eta' K^\pm$ measured by CLEO can be explained by the Cabibbo-allowed internal W-emission process $b\to c\bar cs$ followed by a conversion of the $c\bar c$ pair into the $\eta'$ via gluon exchanges characterized by a decay constant of order -50 MeV. Implications are discussed. The mechanism of the transition $c\bar c\to\eta'$, if correct, will enhance the decay rates of $B\to \eta' K^{*}$ by more than an order of magnitude. However, it plays only a minor role to the rare decays $B\to \eta'(\eta)\pi(\rho)$. The predicted branching ratio of $B^\pm\to \eta\pi^\pm$ for positive $\rho$ is marginally ruled out by experiment, indicating that the favored Wolfenstein parameter $\rho$ is negative.

We present the first high-speed optoelectronic very large scale integrated circuit (VLSI) switching chip using III-V optical modulators and detectors flip-chip bonded to silicon CMOS. The circuit, which consists of an array of 16/spl times/1 switching nodes, has 4096 optical detectors and 256 optical modulators and over 140K transistors. All but two of the 4352 multiple-quantum-well diodes generate photocurrent in response to light. Switching nodes have been tested at data rates above 400 Mb/s per channel, the delay variation across the chip is less than /spl plusmn/400 ps, and crosstalk from neighboring nodes is more than 45 dB below the desired signal. This circuit demonstrates the ability of this hybrid device technology to provide large numbers of high-speed optical I/O with complex electrical circuitry.

Weak current-induced baryonic form factors at zero recoil are evaluated in the rest frame of the heavy parent baryon using the nonrelativistic quark model. Contrary to previous similar work in the literature, our quark model results do satisfy the constraints imposed by heavy quark symmetry for heavy-heavy baryon transitions at the symmetric point $v\cdot v'=1$ and are in agreement with the predictions of the heavy quark effective theory for antitriplet-antitriplet heavy baryon form factors at zero recoil evaluated to order $1/m_Q$. Furthermore, the quark model approach has the merit that it is applicable to any heavy-heavy and heavy-light baryonic transitions at maximum $q^2$. Assuming a dipole $q^2$ behavior, we have applied the quark model form factors to nonleptonic, semileptonic and weak radiative decays of the heavy baryons. It is emphasized that the flavor suppression factor occurring in many heavy-light baryonic transitions, which is unfortunately overlooked in most literature, is very crucial towards an agreement between theory and experiment for the semileptonic decay $\Lambda_c\to\Lambda e^+\nu_e$. Predictions for the decay modes $\b,~\Lambda_c \to p\phi,~\Lambda_b\to\Lambda\gamma$, $\Xi_b\to\Xi\gamma$, and for the semileptonic decays of $\Lambda_b,~\Xi_{b,c}$ and $\Omega_b$ are presented. }, Comment: Latex, 20 pages. Ref.[4] is corrected and Ref.[19] is updated

Based on the factorization approach, we show that the CLEO data for the ratio {Gamma}({ital B}{r_arrow}{psi}{ital K}{sup *})/{Gamma}({ital B}{r_arrow}{psi}{ital K}) and the CDF measurement of the fraction of longitudinal polarization in {ital B}{r_arrow}{psi}{ital K}{sup *} can be accounted for by the heavy-flavor-symmetry approach for heavy-light form factors provided that the form factor {ital F}{sub 0} behaves as a constant, while the {ital q}{sup 2} dependence is of the monopole form for {ital F}{sub 1}, {ital A}{sub 0}, {ital A}{sub 1}, and of the dipole behavior for {ital A}{sub 2} and {ital V}. This {ital q}{sup 2} extrapolation for form factors is further supported by {ital B}{r_arrow}{ital K}{sup *}{gamma} data and by a recent QCD sum-rule analysis. We then apply this method to {ital B}{r_arrow}{ital D}({ital D}{sup *}){pi}({rho}) decays to extract the parameters {ital a}{sub 1} and {ital a}{sub 2}. It is found that {ital a}{sub 1}({ital B}{r_arrow}{ital D}{sup (*)}{pi}({rho}))=1.01{plus_minus}0.06 and {ital a}{sub 2}({ital B}{r_arrow}{ital D}{sup (*)}{pi}({rho}))=0.23{plus_minus}0.06. Our result {ital a}{sub 2}/{ital a}{sub 1}=0.22{plus_minus}0.06 thus significantly improves the previous analysis that leads to {ital a}{sub 2}/{ital a}{sub 1}=0.23{plus_minus}0.11. We argue that, contrary to what is anticipated from the leading 1/{ital N}{sub {ital c}} expansioon, the sign of {ital a}{sub 2}({ital B}{r_arrow}{psi}{italmore » K}{sup (*)}) should be positive and {ital a}{sub 2}({ital B}{r_arrow}{psi}{ital K}{sup (*)}){approx_gt}{ital a}{sub 2}({ital B}{r_arrow}{ital D}{sup (*)}{pi}({rho})).« less

The reproducible fabrication of narrow (∼1.1 μm wide) mesas for InP-InGaAsP buried heterostructure lasers requires development of high quality stepper lithography and anisotropic dry etching of both the SiO 2 etch/regrowth mask and the underlying semiconductor. Using a contrast enhancement method we demonstrate production of 1.1 μm photoresist lines with excellent uniformity (≤7% variation in width) over 2 in. O wafers. High fidelity pattern transfer to the underlying SiO 2 is achieved using a low pressure (1 mTorr) electron cyclotron resonance (ECR) SF 6 /Ar discharge with low additional dc bias (-75 V) on the sample

Owing to printing errors, [Appl. Opt. 35, 2439 (1996)] several figures were illegible. The figures are reprinted and briefly reviewed.

We have fabricated vertical-cavity surface-emitting lasers (VCSELs) which, for the first time, effectively combine a shallow ion implanted aperture, for current confinement under a thin highly conducting lateral current injection layer, and an independent index guide for optical beam confinement (I/sup 2/-VCSELs). Both features are possible only because they are made before a top dielectric mirror is deposited and patterned, and are photolithographically defined for improved size reproducibility compared to oxide-confined designs. The devices emit near 980 nm and have optical power outputs of 1 mW at 2.5-mA input. The 12-VCSEL design also easily incorporates coplanar contacts allowing us to operate flip-chip bonded I/sup 2/-VCSEL's on silicon test chips at data rates of nearly 1 Gb/s.

We describe the first integration of vertical-cavity surface-emitting laser arrays with gigabit-per-second CMOS circuits via flip-chip bonding.

A repeater array consisting of clocked-sense-amplifier-based optical receivers driving receivers driving 850-nm optical modulators is used to demultiplex a 2.48-Gb/s optical signal into eight 311-Mb/s optical data streams. The synchronous detection provided by the clocked receivers allows 2.48-Gb/s signals to be demultiplexed despite a repeater bandwidth of roughly 350 MHz. The repeater array contains 16 elements, is fully functional, and is realized in a hybrid MQW/CMOS smart pixel optoelectronic VLSI technology. The CMOS circuits are made in a 0.35-/spl mu/m linewidth process. Total power dissipation for the entire array is 11.5 mW, and 120-fJ optical input signals are used.

In the past, hardware realization of digital signal processing elements have been based upon binary arithmetic concepts. Because of the dependence between digits in binary arithmetic operations, the hardware required to construct arithmetic elements is cumbersome. In the residue number system, arithmetic operations can be performed with complete independence between digits and a corresponding reduction in hardware complexity. In fact, using current technology, arithmetic operations can be carried out using arrays of look-up tables placed in high density ROMs. This paper discusses the application of the residue number system to realizing digital signal processing elements using such arrays and advantages and disadvantages over conventional realizations are discussed. Examples are given of recursive filter and FFT butterfly element realization.

This paper considers an implementation of the FFT based upon the residue number system. This system offers the advantages of using integer based arithmetic operations and a simple hardware realization involving table look-up arrays. The proposed architecture is such that rapid evolutionary changes in read-only-memory technology can be easily incorporated into the hardware realization. In this paper, a generalized expression for predicting RMS relative error that includes A/D quantization, integer normalization and scaling rounding considerations, has been derived. This analysis leads to the optimal choice of several parameters, which are related to error minimization and simplification of the hardware realization. The generalized expression derived with respect to the FFT can also be used to predict errors in high-speed convolution filters.

We introduce the concept of synchronous smart-pixel optical receivers, and present the first use of a clocked-sense amplifier as a smart-pixel optical receiver. Such a receiver uses the controlled application of positive feedback to obtain low-power compact digital amplification. We describe the design and simulation of two types of optical receivers based on a clamped bit-line sense amplifier (CBLSA), and a conventional sense amplifier (CSA). Both of these circuits have been realized in 0.8 micron-linewidth foundry CMOS with hybrid-bonded GaAs-AlGaAs MQW detectors and modulators attached to the circuit. Operation in excess of 750 Mb/s is demonstrated, within a layout area of 44 /spl mu/m/spl times/22 /spl mu/m, with a bias-dependent estimated power dissipation of 1 to 2 mW. Operation with one or two input beams is possible, with approximate minimum detected photocurrent levels at 320 Mb/s of 8 /spl mu/A (/spl sim/100 fJ) for single-beam operation and 2.5 /spl mu/A/beam (/spl sim/30 fJ/beam) for two-beam operation, all in the CBLSA-based circuit.

We have made two-beam smart-pixel optical receivers using a hybrid attachment of GaAs-AlGaAs multiple quantum-well (MQW) pin devices to foundry-fabricated 0.8-/spl mu/m linewidth CMOS circuits. Results from a repeater in which receiver output is coupled to a transmitter circuit driving a differential pair of MQW modulators are reported. When tested with high-contrast, directly-modulated laser diodes, an optical energy of 26 fJ (-21.5 dBm) in each beam is required to obtain a bit error rate of 1/spl times/10/sup -9/ at 622 Mb/s, and operation at this error rate is observed to 1 Gb/s. The described receiver (one of several we have made) has three amplification stages, with the first being of the transimpedance type. The reported receiver fits easily within a 45/spl times/25 /spl mu/m area, and the entire repeater circuit draws about 2 mA from a 5-V power supply, with the transmitter accounting for about 20 percent of the total.

We describe 8/spl times/8 arrays of smart pixels, designed and fabricated using MQW modulators and detectors flip-chip-solder-bonded to silicon CMOS circuits. The individual circuits implement 2 input, 1 output embedded control switching nodes. Four arrays from two different designs were fabricated and tested. For the array with the highest yield, 60 of 64 nodes functioned correctly at low speeds and were tested up to 250 Mb/s without re-adjusting individual bias voltages with the maximum speed of an individual node of 375 Mb/s. For the second-generation array, the center 4/spl times/8 section of the array was tested at data rates beyond 700 Mb/s with individual nodes having short term bit error rates below 10-/sup 11/.

This paper describes multimodal systems for ad-hoc search constructed by IBM for the TRECVID 2003 benchmark of search systems for broadcast video. These systems all use a late fusion of independently developed speech-based and visual content-based retrieval systems and outperform our individual retrieval systems on both manual and interactive search tasks. For the manual task, our best system used a query-dependent linear weighting between speech-based and image-based retrieval systems. This system has mean average precision (MAP) performance 20% above our best unimodal system for manual search. For the interactive task, where the user has full knowledge of the query topic and the performance of the individual search systems, our best system used an interlacing approach. The user determines the (subjectively) optimal weights A and B for the speech-based and image-based systems, where the multimodal result set is aggregated by combining the top A documents from system A followed by top B documents of system B and then repeating this process until the desired result set size is achieved. This multimodal interactive search has MAP 40% above our best unimodal interactive search system.

We accomplish the integration of GaAs-AlGaAs multiple quantum well modulators directly on top of active silicon CMOS circuits. This enables optoelectronic VLSI circuits to be achieved and also allows the design and optimization of the CMOS circuits to proceed independently of the placement and the bonding of surface-normal optical modulators to the circuit. Using this technique, we demonstrate operation of a 0.8 micron CMOS transimpedance receiver-transmitter circuit at 375 Mb/s. >

We demonstrate integration of GaAs-AlGaAs multiple quantum well modulators to silicon CMOS circuitry via flip-chip solder-bonding followed by substrate removal. We obtain 95% device yield for 32/spl times/32 arrays of devices with 15 micron solder pads. We show operation of a simple circuit composed of a modulator and a CMOS transistor. >

The interactions between the CAD tools that are used to configure the routing resources of a field-programmable gate array (FPGA) and the design of the routing architecture itself are examined. Such an understanding is used to determine where to reduce the number of routing switches in the FPGA while maintaining routability. Experiments are used to study a switch block that was previously thought to have unacceptably low flexibility. It is shown that the performance of this switch block can be improved by adapting the global router to require less flexibility in the architecture, and by careful placement of physical pins on the logic blocks. It is demonstrated that the fewest routing switches are required when each logical pin appears on only one side of the logic cell rather than two or more. >

For several years we have been developing an optoelectronic/VLSI (OE/VLSI) chip technology based on flipchip bonding of GaAs optoelectronic chips onto CMOS silicon followed by substrate removal. Our optoelectronic devices are currently surface normal modulators, which also function as the input detectors. Finally, we have demonstrated an OE/VLSI switching chip with >140000 CMOS gates and 4352 modulators that operated with a clock rate of 400 Mbit/sec.

A two-beam optical repeater circuit operates to 1 Gb/s, consumes 10 mW, occupies about 1100 /spl mu/m/sup 2/, and is realized with a technology capable of providing thousands of optical inputs and outputs to foundry-grade VLSI silicon CMOS circuitry. The technology provides this capability by attaching GaAs/AlGaAs multiple-quantum-well (MQW) modulators and detectors to VLSI CMOS with flip-chip solder bonding. The main unique features are summarized.

We present a novel application of opto-electronic/VLSI technology to the AMOEBA switch: an Asynchronous Multiprocessor Opto-Electronic Bit-sliced Array switch. The AMOEBA switch is intended to function as a high-performance single-chip central switch on a data network serving multiple processors or computers. The purpose of the opto-electronic/VLSI chip is to provide byte-wide, switched optical interconnection at the processor clock rate.

We present AMOEBA: a single-chip asynchronous multiprocessor optoelectronic bit-sliced arrayed crossbar switch intended to provide switched interconnection between multiple processors in a distributed computing environment. AMOEBA relies on optoelectronic-VLSI integration, free-space optical interconnects, and wavelength-and-space-division multiplexed networking on single-mode fiber. We report the implementation and testing of a first generation, 16-channel prototype of the switch and a compact opto-mechanical transceiver package that accomplishes the free-space-to-fiber interfacing.

We present the first operation of an OE/VLSI compatible single-beam receiver-transmitter pair operating to 1 Gb/s. The circuits were realized in 0.35 micron CMOS and hybridized via a flip-chip bonding technique to an array of 850 nm MQW modulator/detectors.

Two-dimensional arrays of optical receivers become interesting as we try to pack more information into smaller spaces, as might be encountered in optical interconnect applications. We have realized a two-dimensional array of such receivers, and coupled their outputs off-chip both electrically and optically, by using a previously described hybrid process whereby multiple-quantum-well modulator/detectors are attached to CMOS circuits. We have demonstrated 622 Mb/s operation of receivers in the array, and found that roughly a 2.5 dB penalty is incurred for operation of nearly the whole array as compared to an isolated element at 311 Mb/s.

The efficacy of many system-designs based on free-space optical interconnects and smart-pixels, depends on the availability of a flexible, high-density, silicon-compatible, optoelectronic technology platform. To this end, we demonstrate the hybrid 3D integration of GaAs-AlGaAs 850nm multiple quantum well (MQW) detectors and modulators directly over active 0.8 /spl mu/m silicon CMOS circuits. To test this technique, a self electro-optic effect device (SEED) input-light detector was flip-chip bonded over a transimpedance receiver circuit, whose output was fed to a simple transmitter circuit and then to another SEED device that served as an output-light modulator.

Two-body charmless nonleptonic decays of Bu and Bd mesons are studied within the framework of generalized factorization in which the effective Wilson coefficientsc eff are renormalization-scale and -scheme independent while factorization is applied to the tree-level hadronic matrix elements. Contrary to previous studies, our c eff do not suffer from gauge and infrared problems. Nonfactorizable effects are parametrized in terms of N eff c (LL) and N eff

Activation of heregulin (HRG) signaling has been implicated in the development of aggressive phenotype in breast cancer cells. The mechanisms through which HRG regulates the progression of breast cancer cells to a more invasive or motile phenotype are currently unknown. Because the process of cell migration must involve dynamic changes in the formation of new focal adhesions at the leading edge and dissolution of preexisting focal points, we explored the potential HRG regulation of paxillin, a major component of focal adhesion. Here, we report that HRG stimulation of noninvasive breast cancer MCF-7 cells resulted in the up-regulation of paxillin mRNA and protein. The observed HRG stimulation of paxillin mRNA expression was completely blocked by actinomycin D (a transcriptional inhibitor) as well as by cycloheximide (a protein synthesis inhibitor), suggesting the involvement of an inducible protein factor(s) and transcriptional regulation of paxillin mRNA by HRG. Extension of these observations to other HRG-responsive human cell lines also demonstrated that HRG has a significant capacity to up-regulate the paxillin expression. Furthermore, the levels of paxillin expression were closely linked with the coexpression of human epidermal growth factor receptor 2 (HER2)/HER3 receptors in breast cancer cell lines and in grade III human breast tumors. This study is the first demonstration of regulation of paxillin expression by a polypeptide growth factor, and it suggests a potential role for paxillin in the HER2 pathway in breast cancer.

Two-body charmless nonleptonic decays of the Bs meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients areµ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of N eff c (LL) and N eff c (LR), the effective numbers of colors arising from (V − A)(V − A) and (V − A)(V + A) four-quark operators, respectively. Branching ratios of Bs → PP,PV,V V decays (P: pseudoscalar meson, V : vector meson) are calculated as a function of N eff c (LR) with two different considerations for N eff

We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal $W$-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations., 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review D

We describe the parallel optical test of a photonic first-in-first-out (PFIFO) buffer memory based on flip-chip CMOS/SEED optoelectronic technology. The PFIFO detects pages of 4 by 8 binary bits, stores them in a 32 bit deep buffer memory, and transmits them in a 16 by 2 output modulator array. All 32 I/O and memory channels functioned, with an average input power of 40 microwatts and a minimum output contrast ratio of 2:1.

This paper describes the VLSI design, layout, and testing of a Hybrid-SEED smart pixel array for a four-stage intelligent optical backplane. The Hybrid-SEED technology uses CMOS silicon circuitry with GaAs-AlGaAs multiple-quantum-well modulators and detectors. The chip has been designed based on the HyperPlane architecture and is composed of four smart pixels which act as a logical 4-bit parallel optical channel. It has the ability to recognize a 4-bit address header, inject electrical data onto the backplane, retransmit optical data, and extract optical data from the backplane. In addition, the smart pixel array can accommodate for optical inversions and bit permutations by appropriate selections of multiplexers. Initial data pertaining to the electrical performance of the chip will be provided and a complete logical description will be given.