gebhart/patrepeval huggingface dataset:
Learning terrain segmentation with classifier ensembles for autonomous robot navigation in unstructured environments (2009)

Abstract Autonomous robot navigation in unstructured outdoor environments is a challenging area of active research and is currently unsolved. The navigation task requires identifying safe, traversable paths that allow the robot to progress toward a goal while avoiding obstacles. Stereo is an effective tool in the near field, but used alone leads to a common failure mode in autonomous navigation in which suboptimal trajectories are followed due to nearsightedness , or the robot's inability to distinguish obstacles and safe terrain in the far field. This can be addressed through the use of machine learning methods to accomplish near‐to‐far learning, in which near‐field terrain appearance and stereo readings are used to train models able to predict far‐field terrain. This paper proposes to enhance existing, memoryless near‐to‐far learning approaches through the use of classifier ensembles that allow terrain models trained on data seen at different points in time to be preserved and referenced later. These stored models serve as memory, and we show that they can be leveraged for more effective far‐field terrain classification on future images seen by the robot. A five‐factor, full‐factorial, repeated‐measures experimental evaluation is performed on hand‐labeled data sets taken directly from the problem domain. The experiments result in many statistically significant findings, the most important being that the proposed near‐to‐far Best‐ K Ensemble Algorithm, with appropriate parameter selection, outperforms the single‐model, nonensemble baseline approach in far‐field terrain classification. Several other findings that inform the use of near‐to‐far ensemble methods are also presented. © 2009 Wiley Periodicals, Inc.
Organocatalytic Asymmetric Multicomponent [C+NC+CC] Synthesis of Highly Functionalized Pyrrolidine Derivatives. (2007)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
6th International Symposium on Molecular Allergology (ISMA) (2016)

Background: Delayed food anaphylaxis upon consumption of red meat is attributed to specific IgE-antibodies directed to galactose--1,3-galactose (-Gal). Anaphylactic reactions may occur after ingestion of meat from different mammals, mainly beef and pork, but reactions to lamb, rabbit or horse have also been reported. In particular, pork kidney has been shown to trigger symptoms that were more severe and occurred within a shorter delay. The objective of the present study was the identification and characterization of pork kidney proteins carrying -Gal carbohydrates and mediating delayed allergic reactions through specific IgE to -Gal. Materials and methods: A cohort of 59 patients with specific IgE to -Gal was screened by immunoblot for IgE-reactive proteins in pork kidney extract. Proteins were purified by affinity chromatography and identified by Edman sequencing and peptide mass fingerprinting. Isolated proteins were used in immunoassays using patient sera and -Gal specific antibodies. Allergenicity was assayed in basophil activation and skin prick test. Results: Multiple IgE-binding proteins were detected in protein extracts of pork kidney by immunoblot using patient sera and an anti--Gal antibody. Reactive bands were located in the high molecular weight range of 100 to 200 kDa. Two major IgE-binding proteins were identified as porcine angiotensin I converting enzyme (ACE I) and aminopeptidase N (AP-N). IgE-binding to both proteins was lost by periodate treatment, resulting in oxidation of carbohydrates. Addition of -Gal inhibited IgE-reactivity to both peptidases. Allergenicity was confirmed by activation of patient basophils and positive skin prick tests. Conclusions: Two IgE-reactive cell membrane peptidases carrying -Gal epitopes were identified in pork kidney, a tissue which is known as potent inducer of red meat-induced anaphylaxis. Allergenicity and clinical relevance of these proteins were confirmed in patients with delayed anaphylaxis to red meat by skin prick test and basophil activation.
ChemInform Abstract: Palladium‐Catalyzed Asymmetric Quaternary Stereocenter Formation. (2012)

Abstract A variety of β,β‐disubstituted carbocyclic, heterocyclic, and acyclic enones undergo a conjugate addition of arylboronic acids in the presence of an optimized Pd(II)/Ag(I) catalyst.
Twisted π-System Chromophores for All-Optical Switching (2011)

Molecular chromophores with twisted π-electron systems have been shown to possess unprecedented values of the quadratic hyperpolarizability, β, with very large real parts and much smaller imaginary parts. We report here an experimental and theoretical study which shows that these twisted chromophores also possess very large values of the real part of the cubic hyperpolarizability, γ, which is responsible for nonlinear refraction. Thus, for the two-ring twisted chromophore TMC-2 at 775 nm, relatively close to one-photon resonance, n(2) extrapolated to neat substance is large and positive (1.87 × 10(-13) cm(2)/W), leading to self-focusing. Furthermore, the third-order response includes a remarkably low two-photon absorption coefficient, which means minimal nonlinear optical losses: the T factor, α(2)λ/n(2), is 0.308. These characteristics are attributed to closely spaced singlet biradical and zwitterionic states and offer promise for applications in all-optical switching.
Sonochemical Synthesis of Mesoporous Titanium Oxide with Wormhole-like Framework Structures (2000)

Ultrasound irradiation is proving to be an excellent method for the synthesis of mesoporous oxides. Here is reported the preparation of titania containing a framework of wormholes—a structural motif of importance for catalysis. Using ultrasonication with a long-chain organic amine as a structure-directing agent, the synthesis was complete in a few hours (the Figure shows particles of the as-prepared material).
Cooling and Quenching of Positronium in Porous Material (2005)

The current status of the experimental study of the cooling of positronium in porous material is reviewed. The cooling and quenching rates of the positronium in a cavity are estimated. The process of mutual quenching of the sub-states of ortho-positronium is also discussed. A possible method for the detection of positronium BEC is suggested.
Broadly neutralizing antibodies abrogate established hepatitis C virus infection (2014)

In most exposed individuals, hepatitis C virus (HCV) establishes a chronic infection; this long-term infection in turn contributes to the development of liver diseases such as cirrhosis and hepatocellular carcinoma. The role of antibodies directed against HCV in disease progression is poorly understood. Neutralizing antibodies (nAbs) can prevent HCV infection in vitro and in animal models. However, the effects of nAbs on an established HCV infection are unclear. We demonstrate that three broadly nAbs-AR3A, AR3B, and AR4A-delivered with adeno-associated viral vectors can confer protection against viral challenge in humanized mice. Furthermore, we provide evidence that nAbs can abrogate an ongoing HCV infection in primary hepatocyte cultures and in a human liver chimeric mouse model. These results showcase a therapeutic approach to interfere with HCV infection by exploiting a previously unappreciated need for HCV to continuously infect new hepatocytes to sustain a chronic infection.
Laser-Induced Line-Narrowing Effects in Coupled Doppler-Broadened Transitions. II. Standing-Wave Features (1972)

Previous theoretical results on the influence of a laser on the line shape of a coupled transition-laser-induced line narrowing-have been restricted to the case where the laser is detuned from the center of its atomic gain profile or is in the form of a traveling wave. This paper extends those results to include the case where the laser is an intense standing-wave field tunable to the center of its atomic gain profile (conditions for Lamb dip). The effect may be observed either in transmission, by probing the coupled transition with a weak traveling-wave field coaxial with the laser field, or else in spontaneous emission from the coupled transition viewed along the axis of the laser field. It is now well known that for a laser detuned from the center of its atomic gain profile, two narrow Lorentzian resonances of different widths appear superimposed upon the broad background signal at frequencies symmetrically located about the corresponding line center. When the laser is tuned to the center of its gain profile, however, additional fine structure develops. This structure, which is particularly significant when the laser field is intense, may have important applications in highresolution spectroscopy and laser-frequency stabilization. In this paper the laser frequency may be smaller or larger than the frequency of the coupled transition. In the latter case an intense laser introduces additional splitting effects, even when the laser is detuned. Splitting effects due to weakly saturating laser fields are also discussed. The problem is formulated by expanding elements of the ensemble-averaged density matrix in an infinite series of spatial Fourier components. A perturbation technique is employed, valid for a weak probe field and a standing-wave field of arbitrary intensity. One obtains an expression for emission induced by the probe field due to atoms moving with one velocity, written in terms of continued fractions in the general case and with Bessel functions in an important special case. This expression is integrated over the atomic velocity distribution by means of a computer to obtain the total emission due to atoms moving with all velocities. In some cases the integrated expressions may be written in closed algebraic form. A detailed discussions of line shapes and of the physical processes involved is included.
Distinct Impact of Alkali-Ion Doping on Electrical Transport Properties of Thermoelectric p-Type Polycrystalline SnSe (2016)

Recent findings about ultrahigh thermoelectric performance in SnSe single crystals have stimulated related research on this simple binary compound, which is focused mostly on its polycrystalline counterparts, and particularly on electrical property enhancement by effective doping. This work systematically investigated the thermoelectric properties of polycrystalline SnSe doped with three alkali metals (Li, Na, and K). It is found that Na has the best doping efficiency, leading to an increase in hole concentration from 3.2 × 10(17) to 4.4 × 10(19) cm(-3) at room temperature, accompanied by a drop in Seebeck coefficient from 480 to 142 μV/K. An equivalent single parabolic band model was found adequate to capture the variation tendency of Seebeck coefficient with doping levels within a wide range. A mixed scattering of carriers by acoustic phonons and grain boundaries is suitable for numerically understanding the temperature-dependence of carrier mobility. A maximum ZT of ∼0.8 was achieved in 1% Na- or K-doped SnSe at 800 K. Possible strategies to improve the mobility and ZT of polycrystals were also proposed.
Development of the Juliá asymmetric epoxidation reaction. Part 2. Application of the oxidation to alkyl enones, enediones and unsaturated keto esters (1996)

Polyleucine-based systems have been used to catalyse the asymmetric oxidation of a variety of alkyl enones 1–4, 9–14, an enynone 16 and a dienone 17 to afford the corresponding epoxides 5–8, 18–26 in good to excellent yield and optical purity. A range of enediones 30–32, 34 and one unsaturated keto ester 33 have also been epoxidised stereoselectivley to afford optically active epoxides 35–39. The epoxidations were carried out with basic peroxide as the oxidant; the polyleucine catalyst was prepared from leucine N-carboxyanhydride using 1,3-diaminopropane, water (employing a humidity cabinet) or a polystyrene immobilised amine as the intiator. Preliminary mass spectral data on material derived from L-leucine and 1,3-diaminopropane (DAP-PLL) suggest that the catalyst consists of material that contains 22 ± 10 leucine residues.
Effects of modeled optical properties on recovered fluorophore concentration during image-guided fluorescence tomography (2013)

In fluorescence molecular tomography, optical measurements at the surface are used with diffusion theory modeling to reconstruct the maps of the fluorophore distribution in the tissue using an iterative error minimization algorithm. While normalizing the fluorescence signal with the excitation signal has been shown to correct for source and detector inconsistencies somewhat, this approach does not always correct for tissue heterogeneities and inaccuracies that are not matched by the forward diffusion model. Using computer simulations and an ultrasound-guided fluorescence tomography (FT) system designed for spatial mapping of Protoporphyrin IX (PpIX), the errors in fluorophore concentration recovery by assignment of incorrect optical properties are analyzed. Using simulations and experiments, white light spectroscopy was used to obtain more accurate tissue properties for forward diffusion model, prior to FT. Using white light spectroscopy the accuracy in FT values improved by 97% on average and the minimal detectable concentration of PpIX with the system was 0.025&mu;g/ml.
Quantum dynamics in nonequilibrium strongly correlated environments (2003)

We consider a biased quantum point contact between two Luttinger liquids measuring a quantum-mechanical system (oscillator). There are three main physical results. First, we find that for voltages higher than the oscillator level spacing, the effect of the measurement is equivalent to coupling to a heat bath, with an effective temperature that only depends on the device $I\ensuremath{-}V$ characteristic. Second, we find that this heating changes the $I\ensuremath{-}V$ characteristics on the junction. Finally, we predict a modulation of the tunneling current at the oscillator frequency. Also, we find that a generalized nonequilibrium fluctuation-dissipation relation connects the decoherence and dissipation of the oscillator to the current-voltage characteristics of the device.
TBIO-15. MODELING DEVELOPMENTAL GENE EXPRESSION DYNAMICS AT CELLULAR RESOLUTION TO INTERPRET PEDIATRIC BRAIN TUMOR TRANSCRIPTIONAL PROGRAMS (2020)

Abstract A central challenge in understanding the biology of pediatric brain tumors is defining the cellular and molecular context where oncogenesis occurs. We hypothesize that spatiotemporally restricted cell types are uniquely susceptible to specific genetic alterations, which alter normal neurodevelopmental programs and ultimately lead to oncogenesis. The resulting tumors retain some transcriptomic features of their lineage of origin. To delineate these origins, we assembled a densely sampled developmental time course of the mouse forebrain and pons, doubling our recently published single-cell atlas. This dataset comprises &amp;gt;100,000 cells at 9 timepoints from E10-P6. However, while single cell transcriptomics reveal rich gene dynamics during cell differentiation, interpretation of individual genes can be challenging due to data sparsity. Leveraging this time-series, we present strategies to model and visualize the expression of a given gene across differentiation of distinct lineages. We demonstrate an interactive web app to interrogate the expression of genes or gene sets during brain development, extract temporally correlated genes, and search active transcription factor regulatory modules. Finally, we profile the expression of core transcriptional programs of several pediatric brain tumor entities during development. Our analyses reveal genes with restricted expression patterns that elucidate tumor etiology. More broadly, these resources harness single cell data to enable exploration of neurodevelopmental gene programs with great relevance to pediatric brain tumor oncogenesis.
Supermolecular self organization via molecular aggregation II. Electro-optical studies on structure formation processes in associated liquid-crystalline diols (1992)

Abstract Orientational correlations are investigated in the isotropic phase for mesogens formed by diols which exhibit a columnar discotic or smectic phase at lower temperatures. These compounds consist of a central part to which either three or only one aliphatic chains of various length (n = 4–14) are attached at one end and two hydroxy groups at the other. The electro-optical studies reveal that associations are formed in the isotropic phase due to hydrogen bonding and that the stability is controlled by the collective association of a number of molecules giving rise to disclike or layer-like aggregates. It seems that these aggregates are responsible for the formation of the columnar phase which is stable at a lower temperature as far as the three chain diols with long aliphatic chains are concerned. The same situation holds for the formation of a smectic phase for the single chain diols. Structure formation in this new class of compounds is thus a function of the shape of the aggregates rather than of the shapes of the individual molecules.
A class of feedback-based coding algorithms for broadcast erasure channels with degraded message sets (2012)

We consider single-hop broadcast erasure channels (BEC) with degraded message sets and instantaneous feedback regularly available from all receivers, and demonstrate that the main principles of the virtual queue-based algorithms in [1], which were proposed for multiple unicast sessions, can still be applied to this setting and lead to capacity achieving algorithms. Specifically, we propose a generic class of algorithms and intuitively describe its rationale and properties that result in its efficiency. We then apply this class of algorithms to three examples of BEC channels (with different numbers of users and 2 or 3 degraded message sets) and show that the achievable throughput region matches a known capacity outer bound. These algorithms do not require any prior knowledge of channel statistics for their operation.
Prospective, Randomized Comparison of One-level Mobi-C Cervical Total Disc Replacement vs. Anterior Cervical Discectomy and Fusion: Results at 5-year Follow-up (2016)

This is a Level I study.
Synchronization over fading dispersive channels (1988)

An investigation is reported of an acquisition system for digital communication over fading dispersive channels that is optimum in the maximum-likelihood sense. A performance measure for the synchronizer in the acquisition mode is defined. Upper and lower bounds on the performance measure are derived. The effective bounds on parameters, such as signal-to-noise ratio, pulse width and modulation, number of pulses, spread of the channel, and the size of the resolution cell, on the performance of the synchronizer is investigated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
MCM-D switching units for interconnection technology validation (2002)

Thin film Multichip Modules (MCM-D) provide a high packaging density. The short interconnection lengths on MCM-D enable high speed digital operations. The analysis of the limits of the high speed performance of such a technology is a challenging task. Individual nets on the substrate are difficult to contact during operation of the module and measuring nets using hf-probes may very well influence the operating conditions of the module. A possible solution to this problem, especially suited for digital applications, is presented here. It consists of a testing methodology focused on the characterization of the interconnection technology itself. This solution provides a way to analyze, in a real-world environment, the electrical performance of a module as a function of geometrical, technological and electrical quantities as well as circuit and system parameters. This solution can bring useful information to MCM manufacturers on the system performance and operation limits of their products, as it can be used as a benchmark to validate the interconnection technology.
10-Gbit/s error-free transmission of 2-ps pulses over a 45-km span using distributed Raman amplification at 1300 nm (2002)

To meet the requirements of upgrading existing optical fiber networks and to considerably extend the potentially useable bandwidth in the low-loss region in optical fibers, broadband, fiber-based amplifiers outside the Er gain window are required. The wavelength flexibility of Raman fiber amplifiers make them very attractive for integration in current and future systems. Here we report the results of 10-Gbit/s, 2-ps transmission at 1300 nm using distributed Raman amplification. Almost no penalty has been observed for the experimental situation where the system loss was directly compensated by the Raman gain and where an excess gain of +8 dB was achieved
Novel ultra-short and ultra-broadband polarization beam splitter based on a bent directional coupler (2011)

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short (<10 μm-long) PBS is designed based on silicon-on-insulator nanowires and the length of the bent coupling region is as small as 4.5 μm while the gap width is chosen as 200 nm (large enough to simplify the fabrication). Numerical simulations show that the present PBS has a good fabrication tolerance for the variation of the waveguide width (more than ± 60 nm) and a very broad band (~200 nm) for an extinction ratio of >10 dB.
Calculated and Experimental Low-Energy Conformations of Cyclic Urea HIV Protease Inhibitors (1998)

One important factor influencing the affinity of a flexible ligand for a receptor is the internal strain energy required to attain the bound conformation. Calculation of fully equilibrated ensembles of bound and free ligand and receptor conformations are computationally not possible for most systems of biological interest; therefore, the qualitative evaluation of a novel structure as a potential high-affinity ligand for a given receptor can benefit from taking into account both the bound and unbound (usually aqueous) low-energy geometries of the ligand and the difference in their internal energies. Although many techniques for computationally generating and evaluating the conformational preferences of small molecules are available, there are a limited number of studies of complex organics that compare calculated and experimentally observed conformations. To assess our ability to predict a priori favored conformations of cyclic HIV protease (HIV-1 PR) inhibitors, conformational minima for nine 4,7-bis(phenylmethyl)-2H-1,3-diazepin-2-ones I (cyclic ureas) were calculated using a high temperature quenched dynamics (QD) protocol. Single crystal X-ray and aqueous NMR structures of free cyclic ureas were obtained, and the calculated low-energy conformations compared with the experimentally observed structures. In each case the ring conformation observed experimentally is also found in the lowest energy structure of the QD analysis, although significantly different ring conformations are observed at only slightly higher energy. The 4- and 7-benzyl groups retain similar orientations in calculated and experimental structures, but torsion angles of substituents on the urea nitrogens differ in several cases. The data on experimental and calculated cyclic urea conformations and their binding affinities to HIV-1 PR are proposed as a useful dataset for assessing affinity prediction methods.