gebhart/patrepeval huggingface dataset:
Design method of freeform off-axis reflective imaging systems with a direct construction process (2014)

In this paper, a novel method is proposed to design the freeform off-axis reflective imaging systems. A special algorithm is demonstrated to calculate the data points on the unknown freeform surface using the rays from multiple fields and different pupil coordinates. These points are used to construct the multiple three-dimensional freeform surfaces in an imaging system which works for a certain object size and a certain width of light beam. An unobscured design with freeform surfaces can be obtained directly with this method, and it can be taken as a good starting point for further optimization. The benefit of this design method is demonstrated by designing a freeform off-axis three-mirror imaging system with high performance and system specifications. The final system operates at F/1.49 with a 64mm entrance pupil diameter and an 8° × 9° field-of-view (FOV). The performance of the system is diffraction limited at LWIR (long-wavelength-infrared).
Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study (2012)

This feasibility study demonstrates the use of MHD effects for synchronization of MR acquisitions with the cardiac cycle.
Impact of Pulsetrain-Burst Ultrafast-Laser Ablation on Viable-Cell Cultures (2012)

We characterize the cellular impact of intense 1-ps laser irradiation at &gt;100MHz repetition rates on viable cell cultures at several incident laser parameters (i.e., pulse intensity and burst duration).
Novel packet routing scheme based on location information for UWB ad-hoc network (2004)

In this paper, a novel packet routing scheme for UWB ad-hoc network is proposed and evaluated. UWB is a kind of spread spectrum communication and it is possible to detect the distance between the nodes. The novel routing scheme proposed in this paper employs UWB's features and controls spreading factor according to the distance between the nodes. With controlling the maximum transmission distance and adopting multi-hop transmission, the throughput performance can be improved as compared to single-hop transmission.
Apoptosis and Dependence Receptors: A Molecular Basis for Cellular Addiction (2004)

Classical signal transduction is initiated by ligand-receptor interactions. We have described an alternative form of signal transduction that is initiated by the withdrawal of ligands from specific receptors referred to as dependence receptors. This process is widespread, featuring in developmental cell death, carcinogenesis (especially metastasis), neurodegeneration, and possibly subapoptotic events such as neurite retraction and somal atrophy. Initial mechanistic studies of dependence receptors suggest that these receptors form complexes that include specific caspases. Complex formation appears to be a function of ligand-receptor interaction, and dependence receptors appear to exist in at least two conformational states. Complex formation in the absence of ligand leads to caspase activation by a mechanism that in at least some cases is dependent on caspase cleavage of the receptor itself, releasing proapoptotic peptides. Thus these receptors may serve in caspase amplification, and in so doing create cellular states of dependence on their respective ligands.
Strain-induced alignment and phase behavior of blue phase liquid crystals confined to thin films (2017)

We report on the influence of surface confinement on the phase behavior and strain-induced alignment of thin films of blue phase liquid crystals (BPs). Confining surfaces comprised of bare glass, dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride (DMOAP)-functionalized glass, or polyvinyl alcohol (PVA)-coated glass were used with or without mechanically rubbing to influence the azimuthal anchoring of the BPs. These experiments reveal that confinement can change the phase behavior of the BP films. For example, in experiments performed with rubbed-PVA surfaces, we measured the elastic strain of the BPs to change the isotropic-BPII phase boundary, suppressing formation of BPII for film thicknesses incommensurate with the BPII lattice. In addition, we observed strain-induced alignment of the BPs to exhibit a complex dependence on both the surface chemistry and azimuthal alignment of the BPs. For example, when using bare glass surfaces causing azimuthally degenerate and planar anchoring, BPI oriented with (110) planes of the unit cell parallel to the contacting surfaces for thicknesses below 3 μm but transitioned to an orientation with (200) planes aligned parallel to the contacting surfaces for thicknesses above 4 μm. In contrast, BPI aligned with (110) planes parallel to confining surfaces for all other thicknesses and surface treatments, including bare glass with uniform azimuthal alignment. Complementary simulations based on minimization of the total free energy (Landau-de Gennes formalism) confirmed a thickness-dependent reorientation due to strain of BPI unit cells within a window of surface anchoring energies and in the absence of uniform azimuthal alignment. In contrast to BPI, BPII did not exhibit thickness-dependent orientations but did exhibit orientations that were dependent on the surface chemistry, a result that was also captured in simulations by varying the anchoring energies. Overall, the results in this paper reveal that the orientations assumed by BPs in thin films reflect a complex interplay of surface interactions and elastic energies associated with strain of the BP lattice. The results also provide new principles and methods to control the structure and properties of BP thin films, which may find use in BP-templated material synthesis, and BP-based optical and electronic devices.
A Multiyear, Large-Scale Comparison of Arthropod Populations on Commercially Managed <I>Bt</I> and Non-<I>Bt</I> Cotton Fields (2005)

Abstract Field studies were conducted in 2000–2002 to compare foliage-dwelling arthropod populations on Bacillus thuringiensis Berliner (Bt) (Bollgard) cotton and non-Bt (conventional) cotton season-long in South Carolina, Georgia, northern Alabama, and southern Alabama. For each of these four regions, three or four paired fields were sampled weekly in each of the 3 yr. Each pair of fields consisted of a Bt and a non-Bt cotton field, both at least 5 ha in size. The dominant arthropod taxa collected included target pests (heliothine moths and Spodoptera spp.), nontarget pests (stink bugs and plant bugs), and generalist natural enemies [Geocoris spp., Orius spp., Solenopsis invicta (Buren), ladybeetles, and spiders]. Where target pests were present, particularly Helicoverpa zea (Boddie), their numbers were consistently significantly lower in the Bt cotton fields. Natural enemy populations generally were not significantly different between the Bt and the non-Bt cotton fields (50% of all comparisons) and, where significant differences were present, natural enemy abundance usually was higher in the Bt than the non-Bt cotton fields. These differences were correlated with lower insecticide use on the Bt than the non-Bt cotton fields, particularly in South Carolina, where target pest pressure was heaviest. When presented with insect eggs or larvae as prey items, the larger natural enemy populations in Bt cotton fields exhibited significantly higher predation rates. These results show that Bt cotton has no significant adverse impacts on the nontarget arthropod populations studied and, compared with insecticide-treated non-Bt cotton, Bt cotton supports higher natural enemy populations with significant positive impacts on biological control.
Ring‐Closing Metathesis Reactions: Interpretation of Conversion–Time Data (2013)

Conversion-time data were recorded for various ring-closing metathesis (RCM) reactions that lead to five- or six-membered cyclic olefins by using different precatalysts of the Hoveyda type. Slowly activated precatalysts were found to produce more RCM product than rapidly activated complexes, but this comes at the price of slower product formation. A kinetic model for the analysis of the conversion-time data was derived, which is based on the conversion of the precatalyst (Pcat) into the active species (Acat), with the rate constant k(act), followed by two parallel reactions: 1) the catalytic reaction, which utilizes Acat to convert reactants into products, with the rate k(cat), and 2) the conversion of Acat into the inactive species (Dcat), with the rate k(dec). The calculations employ two experimental parameters: the concentration of the substrate (c(S)) at a given time and the rate of substrate conversion (-dc(S)/dt). This provides a direct measure of the concentration of Acat and enables the calculation of the pseudo-first-order rate constants k(act), k(cat), and k(dec) and of k(S) (for the RCM conversion of the respective substrate by Acat). Most of the RCM reactions studied with different precatalysts are characterized by fast k(cat) rates and by the k(dec) value being greater than the k(act) value, which leads to quasistationarity for Acat. The active species formed during the activation step was shown to be the same, regardless of the nature of different Pcats. The decomposition of Acat occurs along two parallel pathways, a unimolecular (or pseudo-first-order) reaction and a bimolecular reaction involving two ruthenium complexes. Electron-deficient precatalysts display higher rates of catalyst deactivation than their electron-rich relatives. Slowly initiating Pcats act as a reservoir, by generating small stationary concentrations of Acat. Based on this, it can be understood why the use of different precatalysts results in different substrate conversions in olefin metathesis reactions.
Interaction of rat liver lysosomal membranes with actin. (1984)

Membranes were prepared from lysosomes purified 80-fold by centrifugation in a discontinuous metrizamide gradient. When salt-washed membranes were combined with rabbit muscle actin, an increase in viscosity could be measured using a falling ball viscometer. The lysosomal membrane-actin interaction was actin- and membrane-concentration dependent and appeared to be optimal under presumed physiological conditions (2 mM MgCl2, 1 mM MgATP, neutral pH, and free calcium concentration less than 10(-8) M). The actin cross-linking activity of the membrane was optimal at pH 6.4. The interaction was maximal between 10(-7) and 10(-9) M free calcium ions and inhibited by approximately 50% at concentrations of calcium greater than 0.5 x 10(-7) M. The actin-lysosomal membrane interaction was destroyed if the membranes were pretreated with Pronase, or if the membranes were purified in the absence of protease inhibitors. The interaction was not destroyed if membranes were washed with high salt or extracted with KCl and urea. In addition, a sedimentation assay for the actin-lysosomal membrane interaction was also performed to corroborate the viscometry data. The results suggest the existence of an integral lysosomal membrane actin-binding protein.
Nonlinear dynamics of conduction electrons in organic conductors (2009)

Nonlinear conductivity of organic conductors is explained quantitatively starting from a phenomenological energy-balance equation. Experimental results of ${(\text{TMET-TTP})}_{4}{\text{PF}}_{6}$ are presented, where TMET-TTP is 2-[4, 5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-[4,5-ethylenedithio-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene, and the simulation reproduces the nonlinear properties very well, including the voltage-current characteristics, power-law excess conductivity, and temperature dependence of the threshold field and current. The obtained heat capacity is much smaller than the lattice heat capacity, indicating unimportance of the Joule heating. Since the organic conductors show very little hysteretic switching, the time dependence of the energy balance is traced explicitly, defining nonlinear dynamics of hypothetical electron temperature, which reproduces oscillating states similar to that of the organic thyristor and even chaotic states under certain circumstances. It is expected that transient phenomena such as oscillatory and random outputs in some sort of organic and inorganic nonlinear conductors are quantitatively explained by this method, which in turn affords a playground of nonlinear dynamics.
On the Secrecy Capacity of MIMO Wiretap Channels: Convex Reformulation\n and Efficient Numerical Methods (2020)

This paper presents novel numerical approaches to finding the secrecy\ncapacity of the multiple-input multiple-output (MIMO) wiretap channel subject\nto multiple linear transmit covariance constraints, including sum power\nconstraint, per antenna power constraints and interference power constraint. An\nanalytical solution to this problem is not known and existing numerical\nsolutions suffer from slow convergence rate and/or high per-iteration\ncomplexity. Deriving computationally efficient solutions to the secrecy\ncapacity problem is challenging since the secrecy rate is expressed as a\ndifference of convex functions (DC) of the transmit covariance matrix, for\nwhich its convexity is only known for some special cases. In this paper we\npropose two low-complexity methods to compute the secrecy capacity along with a\nconvex reformulation for degraded channels. In the first method we capitalize\non the accelerated DC algorithm which requires solving a sequence of convex\nsubproblems, for which we propose an efficient iterative algorithm where each\niteration admits a closed-form solution. In the second method, we rely on the\nconcave-convex equivalent reformulation of the secrecy capacity problem which\nallows us to derive the so-called partial best response algorithm to obtain an\noptimal solution. Notably, each iteration of the second method can also be done\nin closed form. The simulation results demonstrate a faster convergence rate of\nour methods compared to other known solutions. We carry out extensive numerical\nexperiments to evaluate the impact of various parameters on the achieved\nsecrecy capacity.\n
Preparation and Characterization of Low Dielectric Methyl Silsesquioxane (MSSQ) Thin Films (2001)

As feature sizes in integrated circuits approach 0.18 ㎛ and below, problems such as interconnect RC delay and crosstalk become more serious. Materials with low dielectric constants are needed&#13;\nto solve these problems. We applied methyl silsesquioxane (MSSQ) as a low dielectric material and studied the film formation condition and the electrical properties of MSSQ films. MSSQ dissolved in a propylene glycol methyl ether acetate (PGMEA) and MSSQ/PGMEA solution was spun on glass substrates at various concentrations. Spinning at 2,500 rpm for 30 sec resulted in films with thicknesses of 6,500 A. Then, we cured the films by heating and measured the electrical properties of samples sandwiched between Al electrodes. The dielectric constant was ~ 2.7, the breakdown strength was about 2.3 MV/cm, and the leakage current was 5.4 X 10-10 A/cm2. Dynamic Mechanical Analysis (DMA) indicated that the curing reaction started at about 200 ℃ and proceeded very fast up to 250 ℃. The structural change in the MSSQ films during curing was monitored by following the Fourier Transform Infrared (FTIR) absorption intensity of the Si-O stretching vibration, which showed that the Si-O structure became more asymmetric during curing and/or network formation.
Use of Adsorbents for Recovery of Acetic Acid from Aqueous Solutions Part II—Factors Governing Selectivity (1987)

Abstract Measurements have been made of uptake of acetic acid and water from low-pH aqueous solution onto polymeric adsorbents and activated carbons. In additon to composite isotherms, isotherms were obtained for acetic acid and water individually by use of gas-chromatographic and Karl Fisher techniques for analyses of both bulk solution and the material taken up by the adsorbent. While capacities for acetic acid are determined by the surface area and the chemical nature of the adsorbent, selectivity is governed by the pore volume and the wetting and swelling tendencies of the sorbent, with the latter being particularly important for polymers. Activated carbons and pyrolyzed polymers give better selectivity than do common polymeric adsorbents. Measurements of pore volume by immersion in various liquids were compared with pore volumes computed from nitrogen adsorption-desorption measurements and from mercury-intrusion porosimetry. The nitrogen adsorption-desorption results were interpreted to obtain micropore and mesopore volumes. The results from the different methods agree well, if allowance is made for lack of full wetting and for swelling tendencies. Higher selectivity for acetic acid over water is obtained for adsorbents having a large percentage of the pore volume as micropores. Measurements of competitive adsorption of acetic acid and methyl ethyl ketone from aqueous solution onto different carbons and pyrolyzed polymers showed that a higher surface density of active hydrogen sites, as measured by reaction with LiAlH4, leads to an improved selectivity for the carboxylic acid.
Anisotropy of light extraction from two-dimensional photonic crystal light-emitting diodes (2007)

Anisotropic light extraction of photonic crystal (PhC) light-emitting diodes in the azimuthal direction has been investigated with an annular structure of triangular PhC lattice. The optical images of the photoluminescence light extraction are obtained with laser excitation. For increasing lattice constant, sixfold symmetric patterns with varying numbers of petals in multiples of six are observed and analyzed. A map of the anisotropy for various lattice constants and numerical apertures is constructed. Several features of light propagations associated with the PhC are observed including the focusing and collimating behaviors.
Battle for the EF-Hands:  Magnesium−Calcium Interference in Calmodulin (1999)

The ubiquitous Ca(2+)-regulatory protein calmodulin activates target enzymes as a response to submicromolar Ca(2+) increases in a background of millimolar Mg(2+). The potential influence of Mg(2+)/Ca(2+) competition is especially intriguing for the N-terminal domain of the protein which possesses the sites with the lowest Ca(2+) specificity. The interdependence of Ca(2+) and Mg(2+) binding in the N-terminal domain of calmodulin was therefore studied using (43)Ca NMR, (1)H-(15)N NMR, and fluorescent Ca(2+) chelator techniques. The apparent affinity for Ca(2+) was found to be significantly decreased at physiological Mg(2+) levels. At Ca(2+) concentrations of an activated cell the (Ca(2+))(2) state of the N-terminal domain is therefore only weakly populated, indicating that for this domain Ca(2+) binding is intimately associated with binding of target molecules. The data are in good agreement with a two-site model in which each site can bind either Ca(2+) or Mg(2+). The Mg(2+)-Ca(2+) binding interaction is slightly positively allosteric, resulting in a significantly populated (Mg(2+))(1)(Ca(2+))(1) state. The Ca(2+) off-rate from this state is determined to be at least one order of magnitude faster than from the (Ca(2+))(2) state. These two findings indicate that the (Mg(2+))(1)(Ca(2+))(1) state is structurally and/or dynamically different from the (Ca(2+))(2) state. The (43)Ca quadrupolar coupling constant and the (1)H and (15)N chemical shifts of the (Mg(2+))(1)(Ca(2+))(1) state were calculated from titration data. The values of both parameters suggest that the (Mg(2+))(1)(Ca(2+))(1) state has a conformation more similar to the "closed" apo and (Mg(2+))(2) states than to the "open" (Ca(2+))(2) state.
Electrolyte dependence of particle motion near an electrode during ac polarization (2013)

The phase angle between the imposed ac electric field and the oscillations in particle height is the key parameter governing the sign of interparticle force during two-dimensional directed assembly. The phase angle depends on a number of experimental parameters, including the frequency of the electric field and dispersing electrolytes. The origin of electrolyte dependence in this phase angle has been a mystery for a decade. Electrolyte dependence arises from polarization of the particle's diffuse layer, which affects the dynamic electrophoretic mobility of the particle. A full description of the magnitude and phase angle of the dynamic electrophoretic mobility was incorporated into a nonlinear integro-differential equation of motion for a 5.7 \ensuremath{\mu}m diameter particle suspended in 0.15 mM KOH, KCl, NaHCO${}_{3}$, NH${}_{4}$OH, and NaOH at frequencies between 5 and 1000 Hz. Integration of the equation revealed that the phase angles for a particle in KOH, NH${}_{4}$OH, and NaOH were smaller than the phase angles calculated for a particle in KCl and NaHCO${}_{3}$, which is consistent with previously published experiments. Although the phase angles for each electrolyte are spread over only \ensuremath{\sim}1\ifmmode^\circ\else\textdegree\fi{}, the results cluster around 90\ifmmode^\circ\else\textdegree\fi{}, which is the crucial boundary between particle aggregation (&gt;90\ifmmode^\circ\else\textdegree\fi{}) and separation (90\ifmmode^\circ\else\textdegree\fi{}). A family of curves of the oscillation in particle height collapsed to a master curve when the amplitude of motion was scaled with the product of the dynamic electrophoretic mobility and electric field strength. These results constitute the first a priori prediction of electrolyte-dependent motion of a particle near an electrode during ac polarization.
Self organizing fuzzy linguistic control with application to arc welding (2002)

Presents a self organizing fuzzy linguistic control strategy that is based on on-line modification of the control rules according to the extent of deviation of the process output from the output of a given reference model. Accordingly, the learning/adaptation algorithm, which is based on the hill climbing approach, modifies the parametrized characteristic functions of the fuzzy subsets describing the control rules, such that the meaning of each rule is iteratively changed to reflect new information regarding the behavior of the process. Simulation results show that this technique improves the overall response of the system in presence of asymmetric dynamic characteristics of the process, proving that this strategy can be a suitable alternative to ordinary fuzzy control. In order to study this self organizing scheme, the authors used a simulation model with similar characteristics as the gas metal arc welding process. This model simulates the variation of the peak surface temperature of the workpiece directly underneath the weld bead in response to changes in the arc current, or more accurately, changes in the electrode wire feedrate.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
Augmented reality system for CT-guided interventions: system description and initial phantom trials (2003)

We are developing an augmented reality (AR) image guidance system, in which information derived from medical images is overlaid onto a video view of the patient. The interventionalist wears a head-mounted display (HMD) that presents him with the augmented stereo view. The HMD is custom fitted with two miniature color video cameras that capture the stereo view of the scene. A third video camera, operating in the near IR, is also attached to the HMD and is used for head tracking. The system achieves real-time performance of 30 frames per second. The graphics appears firmly anchored in the scne, without any noticeable swimming or jitter or time lag. For the application of CT-guided interventions, we extended our original prototype system to include tracking of a biopsy needle to which we attached a set of optical markers. The AR visualization provides very intuitive guidance for planning and placement of the needle and reduces radiation to patient and radiologist. We used an interventional abdominal phantom with simulated liver lesions to perform an inital set of experiments. The users were consistently able to locate the target lesion with the first needle pass. These results provide encouragement to move the system towards clinical trials.