The Unified Segment Tree and its Application to the Rectangle Intersection Problem

In this paper we introduce a variation on the multidimensional segment tree, formed by unifying different interpretations of the dimensionalities of the data structure. We give some new definitions to previously well-defined concepts that arise naturally in this variation, and we show some properties concerning the relationships between the nodes, and the regions those nodes represent. We think these properties will enable the data to be utilized in new situations, beyond those previously studied. As an example, we show that the data structure can be used to solve the Rectangle Intersection Problem in a more straightforward and natural way than had be done in the past.Comment: 14 pages, 6 figure

Binding-incompetent adenovirus facilitates molecular conjugate-mediated gene transfer by the receptor-mediated endocytosis pathway

Molecular conjugate vectors may be constructed that accomplish high efficiency gene transfer by the receptor-mediated endocytosis pathway. In order to mediate escape from lysosomal degradation, we have incorporated adenoviruses into the functional design of the conjugate. In doing so, however, we have introduced an additional ligand, which can bind to receptors on the cell surface, undermining the potential for cell specific targeting. To overcome this, we have treated the adenovirus with a monoclonal anti-fiber antibody, which renders the virus incapable of binding to its receptor. The result is a multi-functional molecular conjugate vector, which has preserved its binding specificity while at the same time being capable of preventing lysosomal degradation of endosome-internalized conjugate-DNA complexes. This finding indicates that adenoviral binding is not a prerequisite for adenoviral-mediated endosome disruption

Ionic profiles close to dielectric discontinuities: Specific ion-surface interactions

We study, by incorporating short-range ion-surface interactions, ionic profiles of electrolyte solutions close to a non-charged interface between two dielectric media. In order to account for important correlation effects close to the interface, the ionic profiles are calculated beyond mean-field theory, using the loop expansion of the free energy. We show how it is possible to overcome the well-known deficiency of the regular loop expansion close to the dielectric jump, and treat the non-linear boundary conditions within the framework of field theory. The ionic profiles are obtained analytically to one-loop order in the free energy, and their dependence on different ion-surface interactions is investigated. The Gibbs adsorption isotherm, as well as the ionic profiles are used to calculate the surface tension, in agreement with the reverse Hofmeister series. Consequently, from the experimentally-measured surface tension, one can extract a single adhesivity parameter, which can be used within our model to quantitatively predict hard to measure ionic profiles.Comment: 14 pages, 6 figure

An O(n^{5/2} log n) Algorithm for the Rectilinear Minimum Link-Distance Problem in Three Dimensions (Extended Abstract)

In this paper we consider the Rectilinear Minimum Link-Distance Problem in Three Dimensions. The problem is well studied in two dimensions, but is relatively unexplored in higher dimensions. We solve the problem in O(B n log n) time, where n is the number of corners among all obstacles, and B is the size of a BSP decomposition of the space containing the obstacles. It has been shown that in the worst case B = Theta(n^{3/2}), giving us an overall worst case time of O(n^{5/2} log n). Previously known algorithms have had worst-case running times of Omega(n^3)

Predicting Foot Positions for Manual Materials Handling Tasks

Copyright © 2005 SAE International For many industrial tasks (push, pull, lift, carry, etc.), restrictions on grip locations and visibility constrain the hand and head positions and help to define feasible postures. In contrast, often the foot locations are minimally constrained and an ergonomics analyst can choose several different stances in selecting a posture to analyze. Also, because stance can be a critical determinant of a biomechanical assessment of the work posture, the lack of a valid method for placing the feet of a manikin with respect to the task compromises the accuracy of the analysis. To address this issue, foot locations and orientations were captured in a laboratory study of sagittal plane and asymmetric manual load transfers. A pilot study with four volunteers of varying anthropometry approached a load located on one of three shelves and transferred the load to one of six shelves. The data illustrate foot placements and behaviors that depend on pickup heights, the use of one or two hands to grasp the object, and the participantsʼ body dimensions. Two distinct pickup and delivery strategies were observed. Split stance, with one foot in front of the other, was markedly more frequent than parallel stance with the feet side by side. A statistical model was developed to predict foot placements at load pickup. This study confirms the importance of this topic and provides the basis for the much more comprehensive study that is now underway

Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Engineering Research Centers Program (Cooperative Agreement EEC-1041895

Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.DoD/National Defense Science & Engineering Graduate Fellowship (NDSEG