gebhart/patrepeval huggingface dataset:
Signal Processing by Model Neural Networks (1992)

Voltage controlled oscillator model neurons (VCONs) are electronic circuits that are similar to phase locked loops, but designed to account for certain experimental observations of neurons. They are constructible electronic circuits, and they provide teaching tools that involve (relatively) simple mathematical models based on brilliant circuits designed by engineers. The model makes accessible the study of phase locking, an important physical phenomenon that makes possible stable frequency-encoded information processing even in the presence of noise. VCONs also enable the design of networks of circuits that might be useful as analog control devices in robotics, give interesting examples of rotation vectors in high-order dynamical systems, and can process, store, and recognize frequency-encoded information. Presented here are several VCON networks motivated by observations by physiologists. They fire bursting patterns similar to neural circuits in the thalamus and reticular complex of mammalian brains; they reproduce searchlight behavior that is speculated to be a mechanism by which a brain focuses attention on one among many competing stimuli; they convert a temporal signal into a spatial pattern of phase locked firing, similar to a tonotopic mapping in mammalian auditory systems; they store frequency-encoded information in autocorrelating filters that are similar to neurotransmitter synapses at chemical equilibrium; and they recognize stored signals by cross-correlation with new inputs. These networks and their computer simulations are presented here.
Learning to Encode Vision on the Fly in Unknown Environments: A Continual Learning SLAM Approach for Drones (2022)

Learning to safely navigate in unknown environ-ments is an important task for autonomous drones used in surveillance and rescue operations. In recent years, a number of learning-based Simultaneous Localisation and Mapping (SLAM) systems relying on deep neural networks (DNNs) have been proposed for applications where conventional feature descriptors do not perform well. However, such learning-based SLAM systems rely on DNN feature encoders trained offline in typical deep learning settings. This makes them less suited for drones deployed in environments unseen during training, where continual adaptation is paramount. In this paper, we present a new method for learning to SLAM on the fly in unknown environments, by modulating a low-complexity Dictionary Learning and Sparse Coding (DLSC) pipeline with a newly proposed Quadratic Bayesian Surprise (QBS) factor. We experimentally validate our approach with data collected by a drone in a challenging warehouse scenario, where the high number of ambiguous scenes makes visual disambiguation hard.
A Convenient and Efficient Synthesis of the First (Nitroimidazolyl)succinic Esters and their Diacids (2006)

We report an easy and efficient synthetic approach to the first series of (nitroimidazolyl)succinic esters and diacids involving the Michael-type addition of the nitroimidazole to the α,β-unsaturated ester. Voltammetric measurements revealed similar redox potentials to those of previous nitroimidazoles used in hypoxia detection. Theoretical calculations were implemented to understand the mechanism of the addition. © Georg Thieme Verlag Stuttgart.
Magnetic Sensing Potential of Fe3O4 Nanocubes Exceeds That of Fe3O4 Nanospheres (2017)

This paper highlights the relation between the shape of iron oxide (Fe<sub>3</sub>O<sub>4</sub>) particles and their magnetic sensing ability. We synthesized Fe<sub>3</sub>O<sub>4</sub> nanocubes and nanospheres having tunable sizes via solvothermal and thermal decomposition synthesis reactions, respectively, to obtain samples in which the volumes and body diagonals/diameters were equivalent. Vibrating sample magnetometry (VSM) data showed that the saturation magnetization (<i>M</i><sub>s</sub>) and coercivity of 100-225 nm cubic magnetic nanoparticles (MNPs) were, respectively, 1.4-3.0 and 1.1-8.4 times those of spherical MNPs on a same-volume and same-body diagonal/diameter basis. The Curie temperature for the cubic Fe<sub>3</sub>O<sub>4</sub> MNPs for each size was also higher than that of the corresponding spherical MNPs; furthermore, the cubic Fe<sub>3</sub>O<sub>4</sub> MNPs were more crystalline than the corresponding spherical MNPs. For applications relying on both higher contact area and enhanced magnetic properties, higher-<i>M</i><sub>s</sub> Fe<sub>3</sub>O<sub>4</sub> nanocubes offer distinct advantages over Fe<sub>3</sub>O<sub>4</sub> nanospheres of the same-volume or same-body diagonal/diameter. We evaluated the sensing potential of our synthesized MNPs using giant magnetoresistive (GMR) sensing and force-induced remnant magnetization spectroscopy (FIRMS). Preliminary data obtained by GMR sensing confirmed that the nanocubes exhibited a distinct sensitivity advantage over the nanospheres. Similarly, FIRMS data showed that when subjected to the same force at the same initial concentration, a greater number of nanocubes remained bound to the sensor surface because of higher surface contact area. Because greater binding and higher <i>M</i><sub>s</sub> translate to stronger signal and better analytical sensitivity, nanocubes are an attractive alternative to nanospheres in sensing applications.
Adenine specific DNAchemical sequencing reaction (1987)

DNA sequence determination according to the method of Maxam and Gilbert utilizes base-specific chemical modification reactions followed by a workup that causes cleavage of the sugar-phosphate backbone at the site of the modified base. Reactions have been reported that are capable of selective cleavage of DNA at G, G + A, A &gt; G, A &gt; C, C, C + T, and T residues. We describe here a simple protocol specific for adenine (A) that may be a useful addition to current chemical sequencing reactions. Reaction of DNA with K_2PdC1_4 at pH 2.0 followed by heating in the presence of piperidine produces an A-specific DNA cleavage reaction. The K_2PdCI_4 reaction involves selective depurination at adenine, affording an excision reaction analogous to the other chemical DNA sequencing reactions.
Tellurite and Fluorotellurite Glasses for Fiberoptic Raman Amplifiers: Glass Characterization, Optical Properties, Raman Gain, Preliminary Fiberization, and Fiber Characterization * (2007)

In this study we report the physical properties and spontaneous Raman scattering spectra of nine oxide tellurite and fluorotellurite glasses from three glass systems—sodium–zinc–tellurite (TZN), tungsten–tellurite, and fluorotellurite. Raman gain and surface damage threshold at 1064 nm are also shown for a selection of these glasses, which all exhibited high gain and damage resistance. Raman gain spectra were directly measured and accurately calculated for selected TZN and fluorotellurite glasses after Fresnel, internal solid angle, and Bose–Einstein corrections. The calculated gain showed good fits to the Raman gain measurements made using a calibrated nonlinear optics apparatus. Infrared and UV‐Vis absorption spectra, characteristic temperatures obtained by differential thermal analysis, densities acquired by the Archimedes principle and refractive indices measured by spectroscopic ellipsometry are also given. The ternary systems TeO 2 –WO 3 –Bi 2 O 3 and TeO 2 –Na 2 O–ZnF 2 and the quaternary system TeO 2 –Na 2 O–ZnO–PbO show promise as Raman amplifiers as they are relatively easy to draw into optical fiber and to these authors' knowledge, this is the first time Raman gain has been presented on halide containing tellurite glasses. The oxyfluoride system studied here, TeO 2 –Na 2 O–ZnF 2 , exhibited a dependence on the peak Raman intensity with ZnF 2 addition. Calculations of preform geometry for mono‐ and multimode guidance and stresses in similar and dissimilar (core suction) core–clad pairs are shown. Dispersion in the mid‐infrared and initial fiber drawing studies are also reported with fibers showing reasonable unclad losses.
Polarization-selective excitation of nitrogen vacancy centers in diamond (2007)

The nitrogen vacancy (NV) center in diamond is promising as an electron spin qubit due to its long-lived coherence and optical addressability. The ground state is a spin triplet with two levels $({m}_{s}=\ifmmode\pm\else\textpm\fi{}1)$ degenerate at zero magnetic field. Polarization-selective microwave excitation is an attractive method to address the spin transitions independently since this allows operation down to zero magnetic field. Using a resonator designed to produce circularly polarized microwaves, we have investigated the polarization selection rules of the NV center. We first apply this technique to NV ensembles in [100]- and [111]-oriented samples. Next, we demonstrate an imaging technique, based on optical polarization dependence, which allows rapid identification of the orientations of many single NV centers. Finally, we test the microwave polarization selection rules of individual NV centers of known orientation.
Fibrocystic change of the breast presenting as a focal lesion mimicking breast cancer in MR imaging (2008)

Focal fibrocystic change (FCC) of the breast is a rare form of FCC. Imaging presentations of focal FCC are not well known. This study aimed to analyze its MR imaging features. Eleven patients of pathology-proven focal FCC were retrospectively studied. Of the 11 patients, seven were mass (>or=5 mm), two showed multiple foci, and two were focus (<5 mm). The lesion size ranged from 4-12 mm (mean 6.7 mm). Morphologically, three patients were suspected as malignancy. Using kinetic enhancement curve, 8 of 13 lesions were suspected to be malignant. Overall, nine patients (82%) were suspected for malignancy using either criterion. Using mammography, 6 of the 11 patients (55%) were diagnosed as malignancy. Breast sonography suspected malignancy in seven patients (7/10, 70%). No statistically significant difference was found in the three diagnostic methods. In pathology, all 11 patients showed the typical pathological features of fibrocystic change, with mixed components of stromal fibrosis, cyst formation, apocrine metaplasia, adenosis, and/or focal sclerosing adenosis. In conclusion, MR imaging features of focal FCC usually present as a mass or focus lesion with rapid enhancement and washout kinetics that mimic a malignant breast lesion and lead to unnecessary operation, especially in patients with contralateral malignant breast cancer.
A theoretical discussion of vector pick-up systems for SQUID magnetometers (1998)

The magnetic induction field produced by non-homogeneously magnetized samples of arbitrary shape is expanded in terms of a complete set of functions, the vector spherical harmonics. The weighing coefficients of this expansion - the multipole moments - are computed and are given up to fifth order for the most common sample shapes and homogeneous magnetization. The magnetic flux threading a general detection coil is computed analytically and pick-up systems of rotational symmetry as well as transverse systems are discussed. The flux profiles of dipole and higher order multipole moments along the direction of the applied field are plotted for common coil geometries as functions of the sample position. Both the influence of position errors on the flux profiles and the crosstalk between mutually perpendicular components of the dipole vector are analysed.
Gene transfer to the rodent placenta in situ. A new strategy for delivering gene products to the fetus. (1998)

The delivery of biologically active factors to the developing mammalian embryo by in utero gene transfer has generated considerable interest but limited success. The chorioallantoic placenta is a potential alternative target for providing therapeutic transgenes to the fetus during gestation. We demonstrate that somatic gene transfer to the midgestation rat placenta may be efficiently accomplished in situ through the implantation of a variety of genetically modified cells with different antigenic and growth properties. Ex vivo-modified cells survived and retained transgene expression until term. Proteins secreted from the transplanted cells were detectable within the fetal trunk blood. These studies suggest that gene transfer to the placenta may be a useful tool for answering questions of both embryonic and placental development and providing therapeutic proteins during gestation for amelioration of diseases with onset during embryonic life.
β-arrestin 2 regulates Aβ generation and γ-secretase activity in Alzheimer’s disease (2013)

Deficits in several neurotransmitter systems are characteristic features of the brains of AD patients. The majority of neurotransmitters communicate information to cells via G protein-coupled receptors (GPCRs) or 7-transmembrane receptors (7TMRs). It has recently been appreciated that a small family of multifunctional GPCR regulatory known as the β-arrestins which play an almost universal role in facilitating traditional GPCR desensitization, are also capable of initiating distinct signals in their own right, conveying receptor subtype-specific signaling events. These signals are often both spatially and temporally distinct, and result in unique cellular and physiological or pathophysiological consequences. As mediators of GPCR desensitization, trafficking and cell signaling, the β-arrestins provide a putative basis to understand GPCR dysfunction in AD. Here, we report that β-arrestin 2 levels are elevated in two independent cohorts of patients with AD. Genetic deletion of Arrb2 (β-arrestin 2) reduces accumulation of the amyloid-β (Aβ) peptide in an AD mouse model. Consistent with these observations, endogenous murine Aβ generation is also reduced in Arrb2-/- mice. Elucidation of the mechanism of the β-arrestin 2-mediated effect on Aβ levels indicates that recruitment of β-arrestin 2 to two GPCRs implicated in the pathogenesis of AD, GPR3 and the β2-adrenergic receptor (β2-AR), is required for the promotion of Aβ release. Collectively, these studies identify β-arrestin 2 as a novel avenue for targeting amyloid pathology and GPCR dysfunction in AD.
Secondary isotope effects in intramolecular catalysis. Mono(p-bromophenyl) succinate hydrolysis (1978)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSecondary isotope effects in intramolecular catalysis. Mono(p-bromophenyl) succinate hydrolysisRichard D. Gandour, Valentino J. Stella, Mark Coyne, Richard L. Schowen, and Emilio A. IcazaCite this: J. Org. Chem. 1978, 43, 9, 1705–1708Publication Date (Print):April 1, 1978Publication History Published online1 May 2002Published inissue 1 April 1978https://pubs.acs.org/doi/10.1021/jo00403a017https://doi.org/10.1021/jo00403a017research-articleACS PublicationsRequest reuse permissionsArticle Views56Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Mechanism of Structure Direction in the Synthesis of Si-ZSM-5: An Investigation by Intermolecular 1H-29Si CP MAS NMR (1994)

The role of tetrapropylammonium (TPA) ions as a structure-directing agent in the synthesis of pure-silica ZSM-5 (Si-ZSM-5) is investigated by solid-state NMR. It has previously been proposed that the mechanism of structure direction involves preorganization of silicate species around the TPA ions with subsequent assembly of these inorganic-organic composite structures to yield crystalline Si-ZSM-5 with occluded TPA molecules. However, such structures have not been directly observed. Here, ^1H-^(29)Si CP MAS NMR is performed between the protons of TPA and the silicon atoms of the zeolite framework precursors in a deuterated synthesis medium to probe the relationship between the organic and inorganic components. The ^1H-^(29)Si CP MAS NMR results indicate that short-range intermolecular interactions, i.e., on the order of van der Waals interactions (≈3.3 Å for H to Si), are established during the heating of the zeolite synthesis gel prior to the development of long-range order indicative of the ZSM-5 structure. ^1H-^(13)C CP MAS NMR spectra suggest that the TPA molecules within the composite inorganic-organic structures adopt a conformation similar to that which they have in the zeolite product. These results thus provide the first direct evidence for the existence of preorganized inorganic-organic composite structures during the synthesis of Si-ZSM-5. They also demonstrate the types of noncovalent intermolecular interactions that are relevant to the existence of an organic structure-directing effect. A modified mechanism of structure direction and crystal growth of Si-ZSM-5 is proposed.
[Effect of peptide Livagen on activity of digestive enzymes in gastrointestinal tract and non-digestive organs in rats of different ages]. (2005)

It is stated that Livagen (Lys-Glu-Asp-Ala) is a weakly hydrolyzed peptide. Peptide hydrolases of small intestine do not hydrolyze Livagen even to a small extent. Under in vitro conditions Livagen reduces glycil-L-leucinedipeptidase activity in small intestine by 50%. After two weeks of Livagen administration per os in rats the digestive enzymes activity in young animals reduces, while in old animals it increases. It should be mentioned that the activity of enzymes in old rats after Livagen administration in the majority of cases approaches to the level of the activity in young animals of control group.
ChemInform Abstract: Design and Synthesis of Cyclopenta[g]quinazoline‐Based Antifolates as Inhibitors of Thymidylate Synthase and Potential Antitumor Agents. (2000)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Wide-Field\nMagnetic Field and Temperature Imaging\nUsing Nanoscale Quantum Sensors (2019)

The simultaneous imaging of magnetic\nfields and temperature (MT)\nis important in a range of applications, including studies of carrier\ntransport and semiconductor device characterization. Techniques exist\nfor separately measuring temperature (e.g., infrared (IR) microscopy,\nmicro-Raman spectroscopy, and thermo-reflectance microscopy) and magnetic\nfields (e.g., scanning probe magnetic force microscopy and superconducting\nquantum interference devices). However, these techniques cannot measure\nmagnetic fields and temperature simultaneously. Here, we use the exceptional\ntemperature and magnetic field sensitivity of nitrogen vacancy (NV)\nspins in conformally coated nanodiamonds to realize simultaneous wide-field\nMT imaging at the device level. Our “quantum conformally attached\nthermo-magnetic” (Q-CAT) imaging enables (i) wide-field, high-frame\nrate imaging (100–1000 Hz); (ii) high sensitivity; and (iii)\ncompatibility with standard microscopes. We apply this technique to\nstudy the industrially important problem of characterizing multifinger\ngallium nitride high-electron mobility transistors (GaN HEMTs). We\nspatially and temporally resolve the electric current distribution\nand resulting temperature rise, elucidating functional device behavior\nat the microscopic level. The general applicability of Q-CAT imaging\nserves as an important tool for understanding complex MT phenomena\nin material science, device physics, and related fields.
Distinct Variants at LIN28B Influence Growth in Height from Birth to Adulthood (2010)

We have studied the largely unknown genetic underpinnings of height growth by using a unique resource of longitudinal childhood height data available in Finnish population cohorts. After applying GWAS mapping of potential genes influencing pubertal height growth followed by further characterization of the genetic effects on complete postnatal growth trajectories, we have identified strong association between variants near LIN28B and pubertal growth (rs7759938; female p = 4.0 x 10(-9), male p = 1.5 x 10(-4), combined p = 5.0 x 10(-11), n = 5038). Analysis of growth during early puberty confirmed an effect on the timing of the growth spurt. Correlated SNPs have previously been implicated as influencing both adult stature and age at menarche, the same alleles associating with taller height and later age of menarche in other studies as with later pubertal growth here. Additionally, a partially correlated LIN28B SNP, rs314277, has been associated previously with final height. Testing both rs7759938 and rs314277 (pairwise r(2) = 0.29) for independent effects on postnatal growth in 8903 subjects indicated that the pubertal timing-associated marker rs7759938 affects prepubertal growth in females (p = 7 x 10(-5)) and final height in males (p = 5 x 10(-4)), whereas rs314277 has sex-specific effects on growth (p for interaction = 0.005) that were distinct from those observed at rs7759938. In conclusion, partially correlated variants at LIN28B tag distinctive, complex, and sex-specific height-growth-regulating effects, influencing the entire period of postnatal growth. These findings imply a critical role for LIN28B in the regulation of human growth.
31P nuclear spin singlet lifetimes in a system with switchable magnetic inequivalence: experiment and simulation (2021)

<sup>31</sup>P NMR spectroscopy and the study of nuclear spin singlet relaxation phenomena are of interest in particular due to the importance of phosphorus-containing compounds in physiology. We report the generation and measurement of relaxation of <sup>31</sup>P singlet order in a chemically equivalent but magnetically inequivalent case. Nuclear magnetic resonance singlet state lifetimes of <sup>31</sup>P pairs have heretofore not been reported. Couplings between <sup>1</sup>H and <sup>31</sup>P nuclei lead to magnetic inequivalence and serve as a mechanism of singlet state population conversion within this molecule. We show that in this molecule singlet relaxation occurs at a rate significantly faster than spin-lattice relaxation, and that anticorrelated chemical shift anisotropy can account for this observation. Calculations of this mechanism, with the help of molecular dynamics simulations and <i>ab initio</i> calculations, provide excellent agreement with the experimental findings. This study could provide guidance for the study of <sup>31</sup>P singlets within other compounds, including biomolecules.