Biomedical Engineering

The rapid technological developments of the past decade and the changes in echocardiographic practice brought about by these developments have resulted in the need for updated recommendations to the previously published guidelines for cardiac chamber quantification, which was the goal of the joint writing group assembled by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. This document provides updated normal values for all four cardiac chambers, including three-dimensional echocardiography and myocardial deformation, when possible, on the basis of considerably larger numbers of normal subjects, compiled from multiple databases. In addition, this document attempts to eliminate several minor discrepancies that existed between previously published guidelines. (J Am Soc Echocardiogr 2015; 28: :1-39.).

Background Goal-directed therapy has been used for severe sepsis and septic shock in the intensive care unit. This approach involves adjustments of cardiac preload, afterload, and contractility to balance oxygen delivery with oxygen demand. The purpose of this study ...

In the paper it is shown that the Balanced Business Scorecard (BSC) allows a balance between financial and non financial objectives and performs a quantification of the dimensions of strategy in four areas -financial, customers, processes and potential. Moreover, the BSC provides feedback on internal processes and external outcomes in order to improve further the performance and results in terms of strategy. When the Balanced Scorecard is implemented effectively, can transform strategic planning from an academic exercise in the central nervous of the entire company.

An MRI time course of 512 echo-planar images (EPI) in resting human brain obtained every 250 ms reveals fluctuations in signal intensity in each pixel that have a physiologic origin. Regions of the sensorimotor cortex that were activated secondary to hand movement were identified using functional MRI methodology (FMRI). Time courses of low frequency (cO.1 Hz) fluctuations in resting brain were observed to have a high degree of temporal correlation (P < 10-9 within these regions and also with time courses in several other regions that can be associated with motor function. It is concluded that correlation of low frequency fluctuations, which may arise from fluctuations in blood oxygenation or flow, is a manifestation of functional connectivity of the brain.

Future cell-based therapies such as tissue engineering will benefit from a source of autologous pluripotent stem cells. For mesodermal tissue engineering, one such source of cells is the bone marrow stroma. The bone marrow compartment contains several cell populations, including mesenchymal stem cells (MSCs) that are capable of differentiating into adipogenic, osteogenic, chondrogenic, and myogenic cells. However, autologous bone marrow procurement has potential limitations. An alternate source of autologous adult stem cells that is obtainable in large quantities, under local anesthesia, with minimal discomfort would be advantageous. In this study, we determined if a population of stem cells could be isolated from human adipose tissue. Human adipose tissue, obtained by suction-assisted lipectomy (i.e., liposuction), was processed to obtain a fibroblast-like population of cells or a processed lipoaspirate (PLA). These PLA cells can be maintained in vitro for extended periods with stable population doubling and low levels of senescence. Immunofluorescence and flow cytometry show that the majority of PLA cells are of mesodermal or mesenchymal origin with low levels of contaminating pericytes, endothelial cells, and smooth muscle cells. Finally, PLA cells differentiate in vitro into adipogenic, chondrogenic, myogenic, and osteogenic cells in the presence of lineage-specific induction factors. In conclusion, the data support the hypothesis that a human lipoaspirate contains multipotent cells and may represent an alternative stem cell source to bone marrow-derived MSCs.

We report the application of a simple yet powerful modular pulse compression system based on photonic crystal fibers that improves on incumbent two-photon laser scanning fluorescence microscopy techniques. This system provides more than a sevenfold increase in fluorescence yield when compared with a commercial two-photon microscopy system. From this, we infer pulses of IR radiation of less than 35 fs duration reaching the sample.

Acute kidney injury (AKI) is a clinical condition characterized by acute decline in renal function, with manifestations ranging from minimal elevation of serum creatinine concentration to anuric renal failure. Keeping in view that acquisition of knowledge and research in this important area requires multi-disciplinary collaboration, a group representing members of the Acute Dialysis Quality Initiative and nephrology and critical care societies has established the Acute Kidney Injury Network (AKIN). The First Consensus Conference of this network focused on defining diagnostic and staging criteria for AKI. Changes in serum creatinine levels and urine output were used to define and stage three levels of renal dysfunction. These criteria require evaluation and validation in prospective clinical studies and, perhaps, modifications as more sensitive markers of kidney injury are identified. Other issues that need to be examined include global epidemiology and outcome of AKI and development of strategies to improve outcomes. The vital role of multi-disciplinary conferences for disseminating knowledge and clarifying issues in clinical practice was recognized.

Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and surface modification of superparamagnetic iron oxide nanoparticles, as well as their use for above biomedical applications. r

Allison, J.; Amako, K.; Apostolakis, J.; Araujo, H.; Arce Dubois, P.; Asai, M.; Barrand, G.; Capra, R.; Chauvie, S.; Chytracek, R.; Cirrone, G. A. P.; Cooperman, Gene D.; Cosmo, G.; Cuttone, G.; Daquino, G. G.; Donszelmann, M.; Dressel, M.; Folger, G.; Foppiano, F.; Generowicz, J.; Grichine, V.; Guatelli, S.; Gumplinger, P.; Heikkinen, A.; Hrivnacova, I.; Howard, A.; Incerti, S.; Ivanchenko, V.; Johnson, T.; Jones, F.; Koi, T.; Kokoulin, R.; Kossov, M.; Kurashige, H.; Lara, V.; Larsson, S.; Lei, F.; Link, O.; Longo, F.; Maire, M.; Mantero, A.; Mascialino, B.; McLaren, I.; Mendez Lorenzo, P.; Minamimoto, K.; Murakami, K.; Nieminen, P.; Pandola, L.; Parlati, S.; Peralta, L.; Perl, J.; Pfeiffer, A.; Pia, M. G.; Ribon, A.; Rodrigues, P.; Russo, G.; Sadilov, S.; Santin, G.; Sasaki, T.; Smith, D.; Starkov, N.; Tanaka, S.; Tcherniaev, E.; Tomé, B.; Trindade, A.; Truscott, P.; Urban, L.; Verderi, M.; Walkden, A.; Wellisch, J. P.; Williams, D. C.; Wright, D.; and Yoshida, H., "Geant4 developments and applications" (

In this study, a novel partially parallel acquisition (PPA) method is presented which can be used to accelerate image acquisition using an RF coil array for spatial encoding. This technique, GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is an extension of both the PILS and VD-AUTO-SMASH reconstruction techniques. As in those previous methods, a detailed, highly accurate RF field map is not needed prior to reconstruction in GRAPPA. This information is obtained from several k-space lines which are acquired in addition to the normal image acquisition. As in PILS, the GRAPPA reconstruction algorithm provides unaliased images from each component coil prior to image combination. This results in even higher SNR and better image quality since the steps of image reconstruction and image combination are performed in separate steps. After introducing the GRAPPA technique, primary focus is given to issues related to the practical implementation of GRAPPA, including the reconstruction algorithm as well as analysis of SNR in the resulting images. Finally, in vivo GRAPPA images are shown which demonstrate the utility of the technique.

In this survey we review the image processing literature on the various approaches and models investigators have used for texture. These include statistical approaches of autocorrelation function, optical transforms digital transforms, textural edgeness, structural element, gray tone 'cooccurrence, run lengths, and autoregressive models. We discuss and generalize some structural approaches to texture ~ased on more complex primitives than gray tone. We conclude With some structural-statistical generalizations which apply the statistical techniques to the structural primitives.

The dielectric properties of tissues have been extracted from the literature of the past five decades and presented in a graphical format. The purpose is to assess the current state of knowledge, expose the gaps there are and provide a basis for the evaluation and analysis of corresponding data from an on-going measurement programme. † Present address:

Backpropagation is now the most widely used tool in the field of artificial neural networks. At the core of backpropagation is a method for calculating derivatives exactly and efficiently in any large system made up of elementary subsystems or calculations which are represented by known, differentiable functions; thus, backpropagation has many applications which do not involve neural networks as such. This paper first reviews basic backpropagation, a simple method which is now being widely used in areas like pattern recognition and fault diagnosis. Next, it presents the basic equations for backpropagation through time, and discusses applications to areas like pattern recognition involving dynamic systems, systems identification, and control. Finally, it describes further extensions of this method, to deal with systems other than neural networks, systems involving simultaneous equations or true recurrent networks, and other practical issues which arise with this method. Pseudocode is provided to clarify the algorithms. The chain rule for ordered derivatives-the theorem which underlies backpropagation-is briefly discussed.

Networked Control Systems (NCSs) are spatially distributed systems for which the communication between sensors, actuators, and controllers is supported by a shared communication network. In this paper we review several recent results on estimation, analysis, and controller synthesis for NCSs. The results surveyed address channel limitations in terms of packet-rates, sampling, network delay and packet dropouts. The results are presented in a tutorial fashion, comparing alternative methodologies.

This paper is a review of the theory-of laser beams and resonators. It is meant to be tutorial in nature and useful in scope. No attempt is made to be exhaustive in the treatment. Rather, emphasis is placed on formulations and derivations which lead to basic understanding and on results which bear practical significance.

The experimental study of joint kinematics in three dimensions requires the description and measurement of six motion components. An important aspect of any method of description is the ease with which it is communicated to those who use the data. This paper presents a joint coordinate system that provides a simple geometric description of the three-dimensional rotational and translational motion between two rigid bodies. The coordinate system is applied to the knee and related to the commonly used clinical terms for knee joint motion. A convenient characteristic of the coordinate system shared by spatial linkages is that large joint displacements are independent of the order in which the component translations and rotations occur.

Multilayer neural networks trained with the back-propagation algorithm constitute the best example of a successful gradientbased learning technique. Given an appropriate network architecture, gradient-based learning algorithms can be used to synthesize a complex decision surface that can classify high-dimensional patterns, such as handwritten characters, with minimal preprocessing. This paper reviews various methods applied to handwritten character recognition and compares them on a standard handwritten digit recognition task. Convolutional neural networks, which are specifically designed to deal with the variability of two dimensional (2-D) shapes, are shown to outperform all other techniques.

The goal of this paper is to present a critical survey of existing literature on human and machine recognition of faces. Machine recognition of faces has several applications, ranging from static matching of controlled photographs as in mug shots matching and credit card verification to surveillance video images. Such applications have different constraints in terms of complexity of processing requirements and thus present a wide range of different technical challenges. Over the last 20 years researchers in psychophysics, neural sciences and engineering, image processing analysis and computer vision have investigated a number of issues related to face recognition by humans and machines. Ongoing research activities have been given a renewed emphasis over the last five years. Existing techniques and systems have been tested on different sets of images of varying complexities. But very little synergism exists between studies in psychophysics and the engineering literature. Most importantly, there exists no evaluation or benchmarking studies using large databases with the image quality that arises in commercial and law enforcement applications In this paper, we first present different applications of face recognition in commercial and law enforcement sectors. This is followed by a brief overview of the literature on face recognition in the psychophysics community. We then present a detailed overview of move than 20 years of research done in the engineering community. Techniques for segmentation/location of the face, feature extraction and recognition are reviewed. Global transform and feature based methods using statistical, structural and neural classifiers are summarized

Quantitative analysis has tremendous but mostly unrealized potential in healthcare to support objective and accurate interpretation of the clinical imaging. In 2008, the National Cancer Institute began building the Quantitative Imaging Network (QIN) initiative with the goal of advancing quantitative imaging in the context of personalized therapy and evaluation of treatment response. Computerized analysis is an important component contributing to reproducibility and efficiency of the quantitative imaging techniques. The success of quantitative imaging is contingent on robust analysis methods and software tools to bring these methods from bench to bedside. and we elaborate on the future directions that can further facilitate development and validation of imaging biomarkers using 3D Slicer.

Fiber tract trajectories in coherently organized brain white matter pathways were computed from in vivo diffusion tensor magnetic resonance imaging (DT-MRI) data. First, a continuous diffusion tensor field is constructed from this discrete, noisy, measured DT-MRI data. Then a Frenet equation, describing the evolution of a fiber tract, was solved. This approach was validated using synthesized, noisy DT-MRI data. Corpus callosum and pyramidal tract trajectories were constructed and found to be consistent with known anatomy. The method's reliability, however, degrades where the distribution of fiber tract directions is nonuniform. Moreover, background noise in diffusionweighted MRIs can cause a computed trajectory to hop from tract to tract. Still, this method can provide quantitative information with which to visualize and study connectivity and continuity of neural pathways in the central and peripheral nervous systems in vivo, and holds promise for elucidating architectural features in other fibrous tissues and ordered media. Magn Reson Med 44:625-632,

MENZ, V., ET AL.: Baroreflex Sensitivity and Heart Rate Variability in Coronary Disease Compared to Dilated Cardiomyopathy. This study was designed to compare baroreceptor sensitivity and heart rate variability as measures of cardiac autonomic tone in patients with coronary disease (CAD, n = 49) and idiopathic dilated cardiomyopathy (IDC, n = 130). Time domain heart rate variability, including SDNN, SDANN, and pNN50, was determined during 24-hour Holter ECC. Baroreflex sensitivity was analyzed nonivasively using the phenylephrine method. Baroreflex sensitivity and heart rate variability were comparable between patients with CAD versus IDC (baroreflex sensitivity: 6.1 ±3 vs 6.9 ±5 ms/mmHg; SDNN: 97 ±40vs 114 ± 41 ms; SDANN: 83 ± 33 vs 99 ± 41 ms; pNN50: 3.9 ± 4 vs 9.6 ± 13 ms, P = NS for all comparisons). Likewise, a subgroup analysis of patients with a left ventricular ejection fraction (LVEF) :3 0% showed no significant difference in baroreceptor sensitivity and heart rate variability between IDC and CAD patients. Patients with CAD and an LVEF > 30% had a decreased heart rate variability but not a decreased baroreflex sensitivity compared to patients with IDC and LVEF > 30 % (baroreflex sensitivity: 6.4 ± 4 vs 8.3 ± 6 ms/mmHg, P = NS; SDNN: 98 ± 19 vs 128 ± 42 ms, P < 0.05; SDANN: 86 ± 21 vs 112 ± 43 ms, P < 0.05; pNN50: 4.2 ± 3 vs 12.3 ± 8 ms, P < 0.05). Patients with a markedly depressed LVEF show comparable alterations in cardiac autonomic tone whether they have CAD or IDC. Patients with CAD and preserved LV function, however, have a decreased heart rate variability compared to patients with IDC and preserved LV function. The prognostic significance of these findings will be determined prospectively in a large patient cohort at our institution. (PACE 1998; 21 [Pt. II]:2416-2419 autonomic tone, heart rate variability, baroreceptor sensitivity

Synthetic aperture radar (SAR) is a coherent active microwave imaging method. In remote sensing it is used for mapping the scattering properties of the Earth's surface in the respective wavelength domain. Many physical and geometric parameters of the imaged scene contribute to the grey value of a SAR image pixel. Scene inversion suffers from this high ambiguity and requires SAR data taken at different wavelength, polarization, time, incidence angle, etc.

Dynamic simulations of movement allow one to study neuromuscular coordination, analyze athletic performance, and estimate internal loading of the musculoskeletal system. Simulations can also be used to identify the sources of pathological movement and establish a scientific basis for treatment planning. We have developed a freely available, opensource software system (OpenSim) that lets users develop models of musculoskeletal structures and create dynamic simulations of a wide variety of movements. We are using this system to simulate the dynamics of individuals with pathological gait and to explore the biomechanical effects of treatments. OpenSim provides a platform on which the biomechanics community can build a library of simulations that can be exchanged, tested, analyzed, and improved through a multi-institutional collaboration. Developing software that enables a concerted effort from many investigators poses technical and sociological challenges. Meeting those challenges will accelerate the discovery of principles that govern movement control and improve treatments for individuals with movement pathologies.

A fully probabilistic framework is presented for estimating local probability density functions on parameters of interest in a model of diffusion. This technique is applied to the estimation of parameters in the diffusion tensor model, and also to a simple partial volume model of diffusion. In both cases the parameters of interest include parameters defining local fiber direction. A technique is then presented for using these density functions to estimate global connectivity (i.e., the probability of the existence of a connection through the data field, between any two distant points), allowing for the quantification of belief in tractography results. This technique is then applied to the estimation of the cortical connectivity of the human thalamus. The resulting connectivity distributions correspond well with predictions from invasive tracer methods in nonhuman primate.

To examine the effi cacy of tacrolimus ophthalmic suspension 0.1% in treating severe allergic conjunctivitis. Methods: This was a multicenter, randomized, double-masked, placebo-controlled clinical trial. Fifty-six patients with severe allergic conjunctivitis in whom topical antiallergic agents and corticosteroids had been ineffective were randomized to tacrolimus or placebo treatment. Patients were treated either with tacrolimus or placebo twice-daily for 4 weeks. Severity of objective signs in palpebral and bulbar conjunctiva, limbus, and corneal involvement was assessed using 4 grades. Seven subjective symptoms were evaluated by visual analog scale (VAS) assessment. The primary effi cacy endpoint was change in the total score of objective signs at the end of treatment. The secondary effi cacy endpoints included change in the score for each objective sign and change in the VAS for each subjective symptom. Safety was assessed based on the severity and the incidence of adverse events. Results: Mean change from baseline in total score for objective signs was signifi cantly greater in the tacrolimus (−5.6 ± 5.1) than in the placebo group (−0.1 ± 4.5; P < 0.001). Tacrolimus signifi cantly improved giant papillae ( P = 0.001) and corneal involvement ( P = 0.005). Five subjective symptoms (itching, discharge, hyperemia, lacrimation, and foreign body sensation) were signifi cantly better in the tacrolimus than in the placebo group. The most frequent treatment-related adverse event in the tacrolimus group was mild ocular irritation upon topical instillation, which was well-tolerated. Conclusion: Tacrolimus ophthalmic suspension 0.1% is effective in treating severe allergic conjunctivitis.

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used extensively in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long-term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades. Recently, a resurgence of interest has propelled PCL back into the biomaterials-arena. The superior rheological and viscoelastic properties over many of its aliphatic polyester counterparts renders PCL easy to manufacture and manipulate into a large range of implants and devices. Coupled with relatively inexpensive production routes and FDA approval, this provides a promising platform for the design and fabrication of longer term degradable implants which may be manipulated physically, chemically and biologically to possess tailorable degradation kinetics to suit a specific anatomical site. This review will discuss the application of PCL as a biomaterial over the last two decades focusing on the advantages which have propagated its return into the spotlight with a particular focus on medical devices, drug delivery and tissue engineering.

This paper concerns the spatial and intensity transformations that are required to adjust for the confounding effects of subject movement during fMRI activation studies. We present an approach that models, and removes, movement-related artefacts from fMRI time-series. This approach is predicated on the observation that movement-related effects are extant even after perfect realignment. These effects can be divided into those that are some function of position of the object in the frame of reference of the scanner, and a component that is due to movement in previous scans. This second component depends on the history of excitation experienced by spins in a small volume and consequent differences in local saturation. The spin excitation history will itself be a function of previous positions. This suggests an autoregression-moving average model for the effects of previous displacements on the current signal. We describe such a model and the adjustments for movement-related components that ensue. Our empirical analyses suggest that (in extreme situations) over 90% of fMRI signal can be attributed to movement, and that this artifactual component can be successfully removed.

YMPHOCYTIC hypophysitis is a rare, idiopathic intrasellar lesion that presents with a mass effect and pituitary dysfunction; fewer than 400 cases have been reported to date. 5 Lymphocytic hypophysitis has a marked female predominance and most commonly becomes symptomatic during pregnancy or the postpartum period. The lesion usually presents as a compressive lesion of the anterior pituitary, hypothalamus, or optic apparatus, or appears as endocrinological dysfunction including diabetes insipidus and hormone deficiency. The hypophysitis is hypothesized to be autoimmune in nature, with florid B-cell, T-cell, and plasma cell infiltration of the adenohypophysis.

The commissioning of a three-dimensional treatment planning system requires comparisons of measured and calculated dose distributions. Techniques have been developed to facilitate quantitative comparisons, including superimposed isodoses, dose-difference, and distance-to-agreement ͑DTA͒ distributions. The criterion for acceptable calculation performance is generally defined as a tolerance of the dose and DTA in regions of low and high dose gradients, respectively. The dose difference and DTA distributions complement each other in their useful regions. A composite distribution has recently been developed that presents the dose difference in regions that fail both dose-difference and DTA comparison criteria. Although the composite distribution identifies locations where the calculation fails the preselected criteria, no numerical quality measure is provided for display or analysis. A technique is developed to unify dose distribution comparisons using the acceptance criteria. The measure of acceptability is the multidimensional distance between the measurement and calculation points in both the dose and the physical distance, scaled as a fraction of the acceptance criteria. In a space composed of dose and spatial coordinates, the acceptance criteria form an ellipsoid surface, the major axis scales of which are determined by individual acceptance criteria and the center of which is located at the measurement point in question. When the calculated dose distribution surface passes through the ellipsoid, the calculation passes the acceptance test for the measurement point. The minimum radial distance between the measurement point and the calculation points ͑expressed as a surface in the dose-distance space͒ is termed the ␥ index. Regions where ␥Ͼ1 correspond to locations where the calculation does not meet the acceptance criteria. The determination of ␥ throughout the measured dose distribution provides a presentation that quantitatively indicates the calculation accuracy. Examples of a 6 MV beam penumbra are used to illustrate the ␥ index.

This corrigendum corrects a mistake in , showing anisotropy versus wavelength, in which the breast data from were misplotted and mislabelled. The corrected figure is given here as figure 8(a). (b) shows a close-up of the data from Peters et al (1990), presenting the wavelength dependence of the anisotropy of scattering for the five types of tissue in breast. (a) Figure 8. (a) Corrected version of figure 8, showing anisotropy of scattering versus wavelength. (b) Detail of data from Peters et al (1990), showing wavelength dependence of anisotropy of scattering for the five types of tissue in breast.

The image intensity in magnetic resonance magnitude images in the presence of noise is shown to be governed by a Rician distribution. Low signal intensities (SNR < 2) are therefore biased due to the noise. It is shown how the underlying noise can be estimated from the images and a simple correction scheme is provided to reduce the bias. The noise characteristics in phase images are also studied and shown to be very different from those of the magnitude images. Common to both, however, is that the noise distributions are nearly Gaussian for SNR larger than two.

Poly(lactic-co-glycolic acid) (PLGA) is one of the most successfully developed biodegradable polymers. Among the different polymers developed to formulate polymeric nanoparticles, PLGA has attracted considerable attention due to its attractive properties: (i) biodegradability and biocompatibility, (ii) FDA and European Medicine Agency approval in drug delivery systems for parenteral administration, (iii) well described formulations and methods of production adapted to various types of drugs e.g. hydrophilic or hydrophobic small molecules or macromolecules, (iv) protection of drug from degradation, (v) possibility of sustained release, (vi) possibility to modify surface properties to provide stealthness and/or better interaction with biological materials and (vii) possibility to target nanoparticles to specific organs or cells. This review presents why PLGA has been chosen to design nanoparticles as drug delivery systems in various biomedical applications such as vaccination, cancer, inflammation and other diseases. This review focuses on the understanding of specific characteristics exploited by PLGA-based nanoparticles to target a specific organ or tissue or specific cells.

coming a significant contributor to power dissipation of CMOS circuits as threshold voltage, channel length, and gate oxide thickness are reduced. Consequently, the identification and modeling of different leakage components is very important for estimation and reduction of leakage power, especially for low-power applications. This paper reviews various transistor intrinsic leakage mechanisms, including weak inversion, drain-induced barrier lowering, gate-induced drain leakage, and gate oxide tunneling. Channel engineering techniques including retrograde well and halo doping are explained as means to manage short-channel effects for continuous scaling of CMOS devices. Finally, the paper explores different circuit techniques to reduce the leakage power consumption.

Soft lithography, a set of techniques for microfabrication, is based on printing and molding using elastomeric stamps with the patterns of interest in basrelief. As a technique for fabricating microstructures for biological applications, soft lithography overcomes many of the shortcomings of photolithography. In particular, soft lithography offers the ability to control the molecular structure of surfaces and to pattern the complex molecules relevant to biology, to fabricate channel structures appropriate for microfluidics, and to pattern and manipulate cells. For the relatively large feature sizes used in biology (≥50 µm), production of prototype patterns and structures is convenient, inexpensive, and rapid. Self-assembled monolayers of alkanethiolates on gold are particularly easy to pattern by soft lithography, and they provide exquisite control over surface biochemistry.

Many laboratories have begun to develop brain-computer interface (BCI) systems that provide communication and control capabilities to people with severe motor disabilities. Further progress and realization of practical applications depends on systematic evaluations and comparisons of different brain signals, recording methods, processing algorithms, output formats, and operating protocols. However, the typical BCI system is designed specifically for one particular BCI method and is, therefore, not suited to the systematic studies that are essential for continued progress. In response to this problem, we have developed a documented general-purpose BCI research and development platform called BCI2000. BCI2000 can incorporate alone or in combination any brain signals, signal processing methods, output devices, and operating protocols. This report is intended to describe to investigators, biomedical engineers, and computer scientists the concepts that the BCI2000 system is based upon and gives examples of successful BCI implementations using this system. To date, we have used BCI2000 to create BCI systems for a variety of brain signals, processing methods, and applications. The data show that these systems function well in online operation and that BCI2000 satisfies the stringent real-time requirements of BCI systems. By substantially reducing labor and cost, BCI2000 facilitates the implementation of different BCI systems and other psychophysiological experiments. It is available with full documentation and free of charge for research or educational purposes and is currently being used in a variety of studies by many research groups. University of New York, Albany. His research interests include use of operant conditioning of spinal reflexes as a new model for defining the plasticity underlying a simple form of learning in vertebrates and development of EEG-based communication and control technology for people with severe motor disabilities.

Fundamental and advanced developments in neuro-fuzzy synergisms for modeling and control are reviewed. The essential part of neuro-fuzzy synergisms comes from a common framework called adaptive networks, which unifies both neural networks and fuzzy models. The fuzzy models under the framework of adaptive networks is called adaptive-network-based fuzzy inference system (ANFIS), which possess certain advantages over neural networks. We introduce the design methods for ANFIS in both modeling and control applications. Current problems and future directions for neuro-fuzzy approaches are also addressed

The architecture of an engineered tissue substitute plays an important role in modulating tissue growth. A novel poly(D,L-lactide-co-glycolide) (PLGA) structure with a unique architecture produced by an electrospinning process has been developed for tissue-engineering applications. Electrospinning is a process whereby ultra-fine fibers are formed in a high-voltage electrostatic field. The electrospun structure, composed of PLGA fibers ranging from 500 to 800 nm in diameter, features a morphologic similarity to the extracellular matrix (ECM) of natural tissue, which is characterized by a wide range of pore diameter distribution, high porosity, and effective mechanical properties. Such a structure meets the essential design criteria of an ideal en-gineered scaffold. The favorable cell-matrix interaction within the cellular construct supports the active biocompatibility of the structure. The electrospun nanofibrous structure is capable of supporting cell attachment and proliferation. Cells seeded on this structure tend to maintain phenotypic shape and guided growth according to nanofiber orientation. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique architecture, which acts to support and guide cell growth.