gebhart/patrepeval huggingface dataset:
Surface-Only Spectroscopy for Diffusion-Limited Systems Using Ultra-Low-Temperature DNP MAS NMR at 16.4 T (2020)

The conventional dynamic nuclear polarization (DNP) technique at T ∼ 100 K can enhance sensitivity of magic-angle spinning (MAS) NMR over 100-fold for standard samples containing urea/proline under high-field conditions, B0 = 9.4–16.4 T. In the scene of real applications, however, the achievable enhancement is often much lower than for urea/proline due to faster 1H relaxation (T1H) promoted by molecular segmental fluctuations and methyl group rotations active even at low temperatures, hindering efficient polarization diffusion within the system. Here, we show at 16.4 T that ultra-low temperature (T ≪ 100 K) provides a general way to improve the DNP efficiency for such diffusion-limited systems as we demonstrate on a microcrystalline sample of the tripeptide N-f-MLF-OH. In a further step, the hyperpolarization localized at the crystal surface enabled “surface-only” spectroscopy eliminating background signals from the crystal core. The surface-only data, rather than the currently popular surface-enhanced data, would prove to be useful in many applications in biological and materials sciences.
Channel Modeling and Signal Processing for Probe Storage Channels (2010)

Probe-storage devices employ large arrays of probes to write/read data in parallel in some storage medium, and combine ultra-high density, low access times, and low power consumption. A particular probe-storage technique utilizes thermomechanical means to store and retrieve information in thin polymer films. In this paper, a system-level channel model for the thermomechanical probe-storage channel is presented. Each of the components of the proposed model is derived by extensive characterization of experimentally obtained readback signals from probe recording tests. Moreover, detection techniques that are actually utilized in a probe-storage prototype implementation are described, followed by coding techniques for added reliability in the presence of particles or other impurities of the storage medium. In addition to low-complexity coding constructs, a concatenated coding scheme with an outer LDPC and inner modulation code is considered, in order to establish a benchmark for overall system performance. A novel methodology for joint decoding of outer LDPC and inner (d,k) modulation codes is developed. Furthermore, an optimal soft decoder for the modulation code is proposed, based on a modification of the decoder metrics to accurately account for the probe storage channel output statistics. Experimental results are used throughout the paper to validate the channel model and identify its relevant parameters, as well as to verify the system performance obtained by simulations.
Self-Assembly of Tubular Fullerenes (1995)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-Assembly of Tubular FullerenesTing Guo, Pavel Nikolaev, Andrew G. Rinzler, David Tomanek, Daniel T. Colbert, and Richard E. SmalleyCite this: J. Phys. Chem. 1995, 99, 27, 10694–10697Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July 1995https://pubs.acs.org/doi/10.1021/j100027a002https://doi.org/10.1021/j100027a002research-articleACS PublicationsRequest reuse permissionsArticle Views2199Altmetric-Citations452LEARN 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 options Get e-Alerts
Alzheimerʼs disease and spirochetes; a questionable relationship (1993)

Departments of Neuroscience and Pathology, University of California San Diego, La Jolla, California, USA
Imaging the tympanic membrane oscillation ex vivo with Doppler optical coherence tomography during simulated Eustachian catarrh (2015)

Recently, optical coherence tomography (OCT) was utilized in multiple studies for structural and functional imaging of the middle ear and the tympanic membrane. Since Doppler OCT allows both, the spatially resolved measurement of the tympanic membrane oscillation and high-resolution imaging, it is regarded as a promising tool for future <i>in vivo </i>applications. In this study, Doppler OCT is utilized for the visualization of the tympanic membrane oscillation in temporal bones with simulated Eustachian catarrh, which was realized by generating a depression in the tympanic cavity. The transfer function, meaning the oscillation amplitude normalized to the applied sound pressure, is measured frequency resolved in the range from 0.5 kHz to 6 kHz and with a lateral spatial resolution of 0.4 mm. Typical oscillation patterns could be observed in case of ambient pressure in the tympanic cavity. Under depression the characteristic oscillation patterns were observed with widely congruent appearance but at higher frequencies.
Sampling jitter in charge sampling radio (2012)

This article addresses some implementation challenges in the potentially very energy-efficient charge-sampling radios. Alternative ways to implement charge sampler in charge sampling radio are considered, and the impacts and spectral shape characteristics of the sampling jitter induced signal distortion are analytically studied in these cases. The analysis shows that the spectrum of the distortion caused by the sampling jitter in a charge sampling receiver is not necessary flat, which in turn has direct impacts on the receiver design and dimensioning. The validity of the analytical results is verified with computer simulations. In simulations, both white Gaussian noise-type clock jitter and clock jitter generated by a phase-locked-loop oscillator are considered.
Decomposition and Roughness Analysis of Chemically Amplified Molecular Resist for Reducing Line Width Roughness (2010)

A molecular resist material, which includes only one protecting group per molecule was designed and synthesized as Prot-1. After confirming the structure and purity of Prot-1, resist A formulated with Prot-1 as a base material was prepared. Resist A showed a good contrast curve. To confirm the decomposition behavior by an electron beam (EB) exposure, resist A was analyzed using high performance liquid chromatography (HPLC). From the HPLC analysis, it was found that the dissolution switching of resist A due to EB exposure was caused by a deprotection reaction of Prot-1. We evaluated the resolution and line edge roughness (LER) of resist A using EB lithography. Resist A showed 25 nm half pitch (hp) resolution and a partially resolved 20 nm hp at an exposure dose of 36 µC/cm 2 using an EB writing system with an acceleration voltage ( V ) of 50 kV. The LER of resist A was 3.8 nm (3σ) for a 100-nm-hp line-and-space pattern, which is similar to a ZEP520A non chemically amplified resist. As a result, we confirmed that a uniform deprotection reaction of just one deprotection group of resist A in the exposed area improved LER and resolution.
Negative Capacitance Carbon Nanotube FETs (2017)

As continued scaling of silicon FETs grows increasingly challenging, alternative paths for improving digital system energy efficiency are being pursued. These paths include replacing the transistor channel with emerging nanomaterials (such as carbon nanotubes), as well as utilizing negative capacitance effects in ferroelectric materials in the FET gate stack, e.g., to improve sub-threshold slope beyond the 60 mV/decade limit. However, which path provides the largest energy efficiency benefits—and whether these multiple paths can be combined to achieve additional energy efficiency benefits—is still unclear. Here, we experimentally demonstrate the first negative capacitance carbon nanotube FETs (CNFETs), combining the benefits of both carbon nanotube channels and negative capacitance effects. We demonstrate negative capacitance CNFETs, achieving sub-60 mV/decade sub-threshold slope with an average sub-threshold slope of 55 mV/decade at room temperature. The average ON-current ( ${I}_{ \mathrm{ON}}$ ) of these negative capacitance CNFETs improves by $2.1\times $ versus baseline CNFETs, (i.e., without negative capacitance) for the same OFF-current ( ${I}_{ \mathrm{OFF}}$ ). This work demonstrates a promising path forward for future generations of energy-efficient electronic systems.
Hot-Switching Test of Non-Contact Type MEMS Switch (2007)

This paper presents the performance and power handling properties of a capacitive MEMS switch. The switch is a completely non-contact-type switch built with several capacitors that contain air gaps, and free from contact failures that frequently occur in contact-type switches. The switch was designed for 24 GHz automotive radar applications, and the average RF performance of the fabricated switches includes insertion loss of 0.5 dB and isolation of 20 dB at 24 GHz. The lifetime, power-handling properties, and linearity are examined in a hot-switching mode. After 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> continuous cycles in a hot-switching mode with 18 mW RF input power, mechanical failures or RF performance degradation were not detected. Power handling capacity of 0.9 W under hot-switching condition was achieved.
Loss analysis of a single phase fast transient VRM converter (2004)

This paper analyzes the losses of a stepping inductor converter in the presence of load transients. Stepping inductor converter is a buck VRM topology which only employs a single phase. Stepping inductor converter is very effective in dealing with fast transient and at the same time it can give better steady state efficiency. Occurrences of transient load current changes are measured in a PC and data are used for the comparison to evaluate the real world performance of the stepping inductor converter and the multiphase interleaved buck converter.
ChemInform Abstract: A New Class of Analogues of the Bifunctional Radiosensitizer α‐( 1‐Aziridinylmethyl)‐2‐nitro‐1H‐imidazole‐1‐ethanol (RSU 1069): The Cycloalkylaziridines. (1991)

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.
Research on oxygen recovery systems for use in space capsules (1973)

An improved electrochemical process was investigated for the recovery of oxygen from the atmospheres of manned space capsules. The objective of the proposed system is to recover the oxygen from CO2 with high efficiency and to recover the additional amount of oxygen from water that is required to provide a total oxygen makeup stream of about 2.0 lb/man-day. The carbon from the CO2 must be converted into a readily disposable or usable form. The results are given of initial experiments with a porous stainless steel cathode in a LiCl-KCl electrolyte with small additions of oxide, carbonate, and hydroxide.
IFN-gamma and prostaglandin E2 inhibit IL-4-induced expression of Fc epsilon R2/CD23 on B lymphocytes through different mechanisms without altering binding of IL-4 to its receptor. (1988)

Human rIL-4 specifically induces the expression of the low affinity receptor for IgE (Fc epsilon R2/CD23) on normal B cells and on the Burkitt lymphoma cell line Jijoye. IL-4 does not induce the generation of the second messenger cAMP in Jijoye cells. PGE2 (at 10(-7) M) was found to inhibit by 50% the IL-4 mediated Fc epsilon R2/CD23 induction on Jijoye cells. The PGE2 half maximum inhibitory concentration (1 nM) was comparable to that inducing a half maximal increase of intracellular cAMP (4nM PGE2). 8-bromo-cAMP (10(-3) M), forskolin (10(-5) M), and cholera toxin (100 ng/ml), which increase intracellular cAMP levels, also inhibited by 40 to 80% the IL-4 induced Fc epsilon R2/CD23 expression on Jijoye cells. PGE2 8-bromo-cAMP, forskolin, and cholera toxin also inhibited the IL-4-induced Fc epsilon R2/CD23 expression on normal B lymphocytes. Taken together these data suggest that PGE2 inhibits the IL-4 induced Fc epsilon R2/CD23 through an increase of intracellular cAMP. In contrast, IFN-gamma, which strongly inhibits IL-4-mediated Fc epsilon R2/CD23 expression on Jijoye cells, did not increase intracellular cAMP levels and thus probably acts through another mechanism. IFN-gamma and PGE2 did not inhibit binding of IL-4 to its receptor. It could be excluded that IFN-gamma and PGE2 were acting via an alteration/desensitization of the IL-4R inasmuch as 24 h pre-incubation of Jijoye cells with these agents affected neither the affinity of 125I-IL-4 for its receptor (Kd = 0.8 to 1.5 x 10(-10) M) nor the maximal number of binding sites per Jijoye cells (Bmax = 390 to 550). Furthermore, IFN-gamma and PGE2 did not affect the internalization and degradation of 125I-IL-4. These data demonstrate that PGE2 and IFN-gamma inhibit the IL-4-mediated induction of Fc epsilon R2/CD23 on B lymphocytes via different mechanisms that do not alter the interaction of IL-4 with its receptor.
Biological Stimuli-Induced Phase Transition of a Synthesized Block Copolymer: Preferential Interactions between PNIPAM-b-PNVCL and Heme Proteins (2021)

The beguiling world of functional polymers is dominated by thermoresponsive polymers with unique structural and molecular attributes. Limited work has been reported on the protein-induced conformational transition of block copolymers; furthermore, the literature lacks a clear understanding of the influence of proteins on the phase behavior of thermoresponsive copolymers. Herein, we have synthesized poly(<i>N</i>-isopropylacrylamide)-<i>b</i>-poly(<i>N</i>-vinylcaprolactam) (PNIPAM-<i>b</i>-PNVCL) by RAFT polymerization using <i>N</i>-isopropylacrylamide and <i>N</i>-vinylcaprolactam. Furthermore, using various biophysical techniques, we have explored the effect of cytochrome <i>c</i> (Cyt c), myoglobin (Mb), and hemoglobin (Hb) with varying concentrations on the aggregation behavior of PNIPAM-<i>b</i>-PNVCL. Absorption and steady-state fluorescence spectroscopy measurements were performed at room temperature to examine the copolymerization effect on fluorescent probe binding and biomolecular interactions between PNIPAM-<i>b</i>-PNVCL and proteins. Furthermore, temperature-dependent fluorescence spectroscopy and dynamic light scattering studies were performed to get deeper insights into the lower critical solution temperature (LCST) of PNIPAM-<i>b</i>-PNVCL. Small-angle neutron scattering (SANS) was also employed to understand the copolymer behavior in the presence of heme proteins. With the incorporation of proteins to PNIPAM-<i>b</i>-PNVCL aqueous solution, LCST has been varied to different extents owing to the preferential, molecular, and noncovalent interactions between PNIPAM-<i>b</i>-PNVCL and proteins. The present study can pave new insights between heme proteins and block copolymer interactions, which will help design biomimetic surfaces and aid in the strategic fabrication of copolymer-protein bioconjugates.
Magneto-reactance based detection of MnO nanoparticle-embedded Lewis lung carcinoma cells (2015)

We demonstrate the capacity of detecting magnetically weak manganese oxide (MnO) nanoparticles and the Lewis lung carcinoma (LLC) cancer cells that have taken up these nanoparticles using a novel biosensor based on the magneto-reactance (MX) effect of a soft ferromagnetic amorphous ribbon with a microhole-patterned surface. While the magnetic moment of the MnO nanoparticles is relatively small, and a magneto-impedance based sensor fails to detect them in solution (0.05 mg/ml manganese oxide lipid micellar nanoparticles) and inside cells at low concentrations (8.25 × 104 cells/ml), the detection of these nanoparticles and the LLC cells containing them is achieved with the MX-based sensor, which, respectively, reaches the detection sensitivity of ∼3.6% and 2.8% as compared to the blank cells. Since the MnO nanoparticles are a promising contrast agent for magnetic resonance imaging (MRI) of lung cells, the MX-based biosensing technique can be developed as a pre-detection method for MRI of lung cancer cells.
Enantio- and Diastereoselective Suzuki-Miyaura Coupling with Racemic Bicycles (2019)

Herein we describe a rhodium-catalyzed enantio- and diastereoselective Suzuki-Miyaura cross-coupling between racemic fused bicyclic allylic chlorides and boronic acids. The highly stereoselective transformation allows for the coupling of aryl-, heteroaryl- and vinyl boronic acids and gives access to functionalized bicyclic cyclopentenes which can be converted to other five-membered ring scaffolds with up to five contiguous stereocenters. Preliminary mechanistic studies suggest that these reactions occur with overall retention of the relative stereochemistry and is enantioconvergent for pseudo-symmetric allylic chloride starting materials. In addition, a bicyclic allylic chloride starting material without pseudo-symmetry undergoes a highly enantioselective regiodivergent reaction.
Experimental and scalar beam propagation analysis of an air-silica microstructure fiber (2000)

We study the higher order guided modes in an air-silica microstructure fiber comprising a ring of six large air-holes surrounding a Germanium doped core. We characterize the modes experimentally using an intra-core Bragg grating. The experimentally observed modes are then accurately modeled by beam propagation simulations using an index profile similar to the observed fiber cross section. Theory and experiment confirm the presence of "inner cladding" modes with approximate cylindrical symmetry near the core, similar to conventional cladding modes, but which strongly exhibit the symmetry of the microstructure at large radius. Such modes are useful in fabricating robust tunable grating filters and we show that the Bragg grating is a useful diagnostic to measure their effective indices and intensity profiles.
Locus for Elevated Apolipoprotein B Levels on Chromosome 1p31 in Families With Familial Combined Hyperlipidemia (2002)

Familial combined hyperlipidemia (FCH), a common cause of premature coronary artery disease, is genetically complex and poorly understood. Recently, a major locus on chromosome 1q21-23 exhibiting highly significant linkage was identified in Finnish FCH families by use of a parametric analysis. We now report highly significant evidence of linkage (maximum LOD score 3.8, recombination fraction 0) of an important FCH phenotype, elevated apolipoprotein B (apoB) levels, to a distinctly separate locus on chromosome 1p31 in Dutch pedigrees. ApoB is the major protein on very low density and low density lipoproteins, and elevated apoB levels have been used as a surrogate trait for FCH. Additional microsatellite markers in the 1p31 region were genotyped, and evidence of linkage improved (maximum LOD score 4.7) in a multipoint analysis of two markers in the peak region. The leptin receptor gene resides within this locus and is involved in obesity and insulin/glucose homeostasis. However, there was no evidence of an association between leptin receptor and apoB levels, raising the possibility that another gene on this chromosomal region contributes to elevated apoB levels in this Dutch population. This is one of the first loci identified for apoB levels in humans and is the second major locus implicated in the genetic etiology of FCH.
SUBNANOSECOND PERFORMANCE OF THE BOSS GaAs OPENING SWITCH (2005)

We report recent subnanosecond photoconductive measurements on a p-i-n device made from a coppercompensated semi-insulating GaAs substrate. Photoconductivity in this relatively large volume device (0.5 x 5 x 10 mm3) is generated by extrinsic absorption of a 1-pm laser pulse, and optically quenched with a 2pm laser pulse. Device risetimes on the order of 140 ps are reported along with relatively slow (-ns) fall times. It is shown that these large, high-power (multimegawatt) switches have the potential to switch subnanosecond pulses when a copper-compensated GaAs material with suitably fast electron-hole-pair recombination rate is developed.
Estimation of Gait Characteristics during Walking in Lower Gravity Environment Using a Wearable Device (2018)

Frontiers Events is a rapidly growing calendar management system dedicated to the scheduling of academic events. This includes announcements and invitations, participant listings and search functionality, abstract handling and publication, related events and post-event exchanges. Whether an organizer or participant, make your event a Frontiers Event!
Alternative lengthening of telomeres can be maintained by preferential elongation of lagging strands (2017)

Alternative lengthening of telomeres (ALT) is a telomerase independent telomere maintenance mechanism that occurs in ∼15% of cancers. The potential mechanism of ALT is homology-directed telomere synthesis, but molecular mechanisms of how ALT maintains telomere length in human cancer is poorly understood. Here, we generated TERC (telomerase RNA) gene knockouts in telomerase positive cell lines that resulted in long-term surviving clones acquiring the ALT pathway but at a very low frequency. By comparing these ALT cells with parental telomerase positive cells, we observed that ALT cells possess excessively long telomeric overhangs derived from telomere elongation processes that mostly occur during S phase. ALT cells exhibited preferential elongation of the telomeric lagging strands, whereas telomerase positive cells exhibited similar elongation between leading and lagging strands. We propose that the ALT pathway preferentially occurs at telomeric lagging strands leading to heterogeneous telomere lengths observed in most ALT cancers.
Sulfonated polyisobutylene telechelic ionomers. XIII. Viscosity behavior in nonpolar solvents and nonpolar–polar solvent mixtures (1989)

Abstract The effect of molecular variables upon the dilute solution viscosity of sulfonated polyisobutylene telechelic ionomers has been studied in both nonpolar solvents and nonpolar–polar solvent mixtures. In nonpolar solvents, association of the terminal salt groups results in an increase in viscosity and gelation at very low concentrations. The concentration at which gelation occurs was found to be dependent upon molecular variables such as architecture, molecular weight, neutralizing cation, extent of neutralization, and the type of solvent. Addition of a small amount of a more polar cosolvent tends to break up ionic associations between polymer chains and thus reduces viscosity. Finally, such solutions with a small amount of polar cosolvent may display dramatic increases in viscosity with increasing temperature due to a dynamic equilibrium between the ionic groups on the polymer chain, the nonpolar solvent, and the polar cosolvent. The results of this work suggest that these ionomers may potentially be useful as viscosity modifiers or “thermal thickeners” in some applications.