gebhart/patrepeval huggingface dataset:
Performance analysis of the continuous trace gas preconcentrator (2011)

In gas molecule detection systems, certain trace gas components can go undetected. This is due to ultralow yet dangerous concentrations combined with limitations of the detection methods. To remedy this problem, a preconcentrator can be included in a system to increase the trace gas concentrations, before the gas samples enter the detection unit. The widely used adsorption/desorption preconcentrators enable detection by interrupting the sampled gas flow for significant periods, in order to accumulate detectable periodic concentrations of trace gas molecules. The recently patented continuous trace gas preconcentrator (CTGP) provides a unique approach for enhancing the trace gas concentration, without stopping the flow. In this study, a performance model is developed for the CTGP, by application of the Poiseuille flow coefficients for long tubes. Based on the Cercignani–Lampis scattering kernel, Sharipov calculated the Poiseuille flow coefficients for various geometries and numerous operating Knudsen numbers. The concentrations of sampled molecules were analyzed in this study using Sharipov’s flow coefficients. The results presented here reinforce the potential benefits of the CTGP.
Atmospheric electron X-ray spectrometer development (2002)

The development of a portable surface elemental analysis tool based on the excitation of characteristic X-rays at ambient pressure with an electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major advantages offered by this instrument include rapid spectrum acquisition, nondestructive evaluation of elemental composition, and high spatial resolution in comparison to similar portable instruments. The instrument proof-of-principle has been demonstrated by obtaining energy dispersive X-ray spectra from metal and mineral samples. SEM experiments have been carried out to determine beam spot size and quantitative analysis limits. Modeling has been performed to study performance limits and to understand the influence of membrane and atmosphere interactions on the focused electron beam.
Sub-Millimeter-Wave Polarization-Independent Spatial Power Divider for a Two-Port Dual-Polarized Antenna (2021)

An antenna system is proposed that uses a novel polarization-independent spatial power divider to align the beams from two orthogonally oriented dual-polarized feeds. This antenna system uses a common aperture for transmitting and receiving and provides high port isolation while maintaining compatibility with fully polarimetric radar. Unlike conventional two antenna radar systems, a radar using this antenna does not suffer from the parallax problem. The spatial power divider is designed using an all-dielectric metasurface approach and is fabricated on a silicon wafer using standard micromachining technology. The measured device exhibits at most 0.9 dB of difference between the reflection and transmission for both transverse electric and transverse magnetic incident waves at 45° incidence, over a band from 221 to 250 GHz. Conical horns are fabricated as feeds and together with the spatial power divider, a focusing lens, and microwave absorbers, are assembled in a three-dimensional-printed housing to complete the antenna system. Its measured gain is approximately 39 dB for each port and polarization, and isolation between ports is at least 40 dB for all polarization combinations over the band of interest.
ChemInform Abstract: Stereospecific Synthesis of Conformationally Constrained γ‐Amino Acids: New Foldamer Building Blocks That Support Helical Secondary Structure. (2010)

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.
Nonvolatile memory with molecule-engineered tunneling barriers (2008)

We report a novel field-sensitive tunneling barrier by embedding C60 in SiO2 for nonvolatile memory applications. C60 is a better choice than ultrasmall nanocrystals due to its monodispersion. Moreover, C60 provides accessible energy levels to prompt resonant tunneling through SiO2 at high fields. However, this process is quenched at low fields due to highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap and large charging energy of C60. Furthermore, we demonstrate an improvement of more than an order of magnitude in retention to program/erase time ratio for a metal nanocrystal memory. This shows promise of engineering tunnel dielectrics by integrating molecules in the future hybrid molecular-silicon electronics.
Brillouin flow cytometry for label-free mechanical phenotyping of the nucleus (2017)

The mechanical properties of the nucleus are closely related to many cellular functions; thus, measuring nuclear mechanical properties is crucial to our understanding of cell biomechanics and could lead to intrinsic biophysical contrast mechanisms to classify cells. Although many technologies have been developed to characterize cell stiffness, they generally require contact with the cell and thus cannot provide direct information on nuclear mechanical properties. In this work, we developed a flow cytometry technique based on an all-optical measurement to measure nuclear mechanical properties by integrating Brillouin spectroscopy with microfluidics. Brillouin spectroscopy probes the mechanical properties of material via light scattering, so it is inherently label-free, non-contact, and non-invasive. Using a measuring beam spot of submicron size, we can measure several regions within each cell as they flow, which enables us to classify cell populations based on their nuclear mechanical signatures at a throughput of ∼200 cells per hour. We show that Brillouin cytometry has sufficient sensitivity to detect physiologically-relevant changes in nuclear stiffness by probing the effect of drug-induced chromatin decondensation.
Single-Metal Nanoscale Thermocouples (2014)

We study the generation of thermoelectricity by nanoscale thermocouples (TCs) formed from a single layer of metal with cross-sectional discontinuity. Typically, a TC is formed when a second conductor is inserted between two sections of a first conductor forming two junctions situated at different temperatures. Here, we investigate the behavior of TCs formed not of two conductors but rather nanowires of the same metal of two cross-sectional areas. Monometallic TCs were constructed from a lithographically defined nanowire having one abrupt variation in width along its length, and tested at room temperature; these structures exploit a change in Seebeck coefficient that is present at these size scales. To investigate the thermoelectric properties of such “shape-engineered” TCs, nanoscale heaters were employed to set the local temperatures. Temperature profiles at the hot and cold junctions of the TCs were determined both by simulations and experiments. Results demonstrate that the magnitude of the open-circuit voltage, and hence the relative Seebeck coefficient, is a function of the parameters of the variations in the segment widths. The fabrication complexity of such shape-engineered monometallic nanowire TCs is greatly reduced compared to that of conventional bimetallic TCs, and could be mass-produced using simpler manufacturing techniques.
New Acylated 1,2,4‐Triazoles as Antiviral Agents (1986)

Abstract The syntheses and antiviral properties of the new acylated 1,2,4‐triazole derivatives 4 are described. In cell culture experiments 6 out of 99 compounds specifically inhibit rubella virus replication to a high degree. Structure‐activity relationships are discussed.
Second harmonic generation in dc-biased quantum wells (1987)

It has recently been shown that the dipole matrix elements between subbands in semiconductor quantum wells are extremely large. 1 Third-order nonlinear susceptibilities are proportional to the fourth power of these matrix elements. Large nonlinearities have thus been predicted for these systems, in particular an intensity-dependent index of refraction suitable for use in all-optical logic elements. 1 Second-order nonlinearities vanish identically in symmetric wells, suggesting the use of asymmetrically graded quantum wells for quadratic interactions. 2 External bias electric fields also break the inversion symmetry, resulting in Stark shifts and large quadratic susceptibilities whose sign depends on the direction of the applied field. The magnitude of the nonlinearity depends on the carrier density, the dc bias field, and the detuning of the fundamental and second harmonic frequencies from resonances.
Silk Fibroin Microneedles for Transdermal Vaccine Delivery (2016)

Microneedles represent an exciting departure from the existing parenteral injection paradigm for drug delivery, particularly for the administration of vaccines. While the benefit of delivering vaccine antigens to immunocompetent tissue in the skin has been established, there have been varying degrees of success using microneedles to do so. Here, we investigate the use of silk fibroin protein to produce microneedles and evaluate their ability to deliver vaccines against influenza, <i>Clostridium difficile</i>, and <i>Shigella</i>. Fibroin protein from the silkworm <i>Bombyx mori</i> possesses suitable properties for use in a microneedle system, including all-aqueous processing, mechanical strength in dried formats, biocompatibility, and the ability to temperature stabilize biomacromolecules. As such, this biomaterial combines the processing and biocompatibility advantages of a dissolving microneedle system with the product stability and mechanical strength of coated insoluble microneedles. Through successful vaccination of mice against three separate antigens, we establish that silk fibroin is well-suited for use as a solid-coated microneedle delivery system and offers long-term potential similar to that of the leading microneedle biomaterials.
Oracle's SQL Performance Analyzer. (2008)

We present the SQL Performance Analyzer, a novel approach in Oracle Database 11g to testing database changes, such as upgrades, parameter changes, schema changes, and gathering optimizer statistics. The SQL Performance Analyzer offers a comprehensive solution to enable users to forecast and analyze how a system change will impact SQL query plans and run time performance, so they can tune their system before they make the change in production. The SQL Performance Analyzer identifies potential problems that may occur and makes suggestions for avoiding any SQL performance degradation. It provides quantitative estimates of the system’s performance in the new environment with high confidence and performs a comparative analysis of the response time of the SQL workload thus allowing for an easy assessment of the change. In this paper we describe the architecture of the SQL Performance Analyzer, its usage model, and its integration points with other Oracle database components to form an end-to-end change management solution. 1
Measurement of Botulinum Toxin Activity: Evaluation of the Lethality Assay (1994)

The use of the mouse lethality assay for the estimation of the biologic activity of botulinum toxin was evaluated. The relationship between the number of animals, number of doses, and duration of the assay used to estimate the LD50 and the precision of the assay was investigated. The results of these studies demonstrated that the LD50 for botulinum toxin can be estimated with a high degree of precision (+/- 5%). The precision of the assay is not increased by using more than a 5-dose 50-animal assay or extending the duration of the assay beyond 72 hr. Estimates of the LD50 obtained at 48 hr were only slightly less precise but underestimated the LD50 by 15%. Analysis of the commercially available preparations of botulinum toxin with the mouse LD50 assay revealed significant discrepancies between the units of toxin in these preparations. In addition, a 2.67-fold difference in the relative potency of the two preparations of botulinum A toxin was observed using a regional chemodenervation assay that measures paralysis. The mouse LD50 assay could not detect this large difference in the potency of the two approved clinical preparations of botulinum toxin. The results of these studies demonstrate that although the mouse LD50 assay can be used to estimate the number of units of botulinum toxin with a high degree of precision this assay alone is not an adequate method for assessing the preclinical biological potency of botulinum toxin.
An engineered S1P chaperone attenuates hypertension and ischemic injury (2017)

Endothelial dysfunction, a hallmark of vascular disease, is restored by plasma high-density lipoprotein (HDL). However, a generalized increase in HDL abundance is not beneficial, suggesting that specific HDL species mediate protective effects. Apolipoprotein M-containing HDL (ApoM<sup>+</sup>HDL), which carries the bioactive lipid sphingosine 1-phosphate (S1P), promotes endothelial function by activating G protein-coupled S1P receptors. Moreover, HDL-bound S1P is limiting in several inflammatory, metabolic, and vascular diseases. We report the development of a soluble carrier for S1P, ApoM-Fc, which activated S1P receptors in a sustained manner and promoted endothelial function. In contrast, ApoM-Fc did not modulate circulating lymphocyte numbers, suggesting that it specifically activated endothelial S1P receptors. ApoM-Fc administration reduced blood pressure in hypertensive mice, attenuated myocardial damage after ischemia/reperfusion injury, and reduced brain infarct volume in the middle cerebral artery occlusion model of stroke. Our proof-of-concept study suggests that selective and sustained targeting of endothelial S1P receptors by ApoM-Fc could be a viable therapeutic strategy in vascular diseases.
Unprecedented Role of Hybrid <i>N-</i>Glycans as Ligands for HIV-1 Broadly Neutralizing Antibodies (2018)

The development of an HIV vaccine has been hampered by the extraordinary mutability and genetic diversity of the virus, particularly the substantial sequence diversity of gp120 and gp 41 envelope glycoproteins existing in more than 2000 HIV variants. The highly diverse glycans on HIV spikes are commonly considered as immunologically silent self-antigens; however, the discovery of highly potent broadly neutralizing antibodies (bNAbs) from HIV patients targeting the viral surface glycans has raised a major question about the origin of their antigens. Recent epitope mapping studies of the bNAb PG9 indicated a requirement of a properly spaced high mannose and a complex type glycan connected by a short peptide spacer. We have recently discovered that a 1:1 mixture of Man<sub>5</sub> and sialyl biantennary glycan with well-defined distance and without the peptide spacer is well recognized by PG9 with high avidity and, thus, proposed that a hybrid glycan with oligomannose and complex-type arm could be the proper ligand of PG9. To verify this proposition, we first designed and chemo-enzymatically synthesized a series of unusual hybrid-type N-glycan structures, which may exist on HIV surface glycoproteins through the host-guided N-glycosylation pathway. The synthetic hybrid glycans were then used to prepare glycan arrays for the binding studies of PG9 and several other highly potent bNAbs, including PG16, PGT121, PGT128-3C, 2G12, VRC13, VRC-PG05, VRC26.25, VRC26.09, PGDM1400, 35O22, and 10-1074. Our results demonstrated that PG9 and some other bNAbs bind with strong avidity (subnanomolar K<sub>d</sub>) to certain hybrid structures, suggesting that these unusual glycans may serve as epitopes for the design of vaccines against HIV.
PLANAR: RNA Sequence Alignment using Non-Affine Gap Penalty and Secondary Structure (2006)

An important component of bioinformatics research is aimed at finding evolutionary relationships among species, since it allows us to better understand various important biological functions as they emerged in these species. These tools simultaneously trace the associated evolutionary history. In this context, sequence alignment is commonly used to understand similarities among the species by comparing their genomic, transcriptomic and proteomic sequence data. In our earlier research, we devised P LAINS (PiecewiseLinear Alignment with Important Nucleotide Seeker) to align genomic DNA sequences using a general class of gap distribution model. This paper proposes P LANAR (Piecewise-Linear Alignment for Nucleotides Arranged as RNA), a variant of PLAINS designed for aligning RNA sequences, while properly accounting for their secondary structures. This paper presents an overview of the PLANAR algorithm, and compares it to other competing RNA alignment tools, while emphasizing many interesting correlations discovered in the process.
<title>Triage of OCR results using confidence scores</title> (2001)

We describe a technique for modeling the character recognition accuracy of an OCR system -- treated as a black box -- on a particular page of printed text based on an examination only of the output top-choice character classifications and, for each, a confidence score such as is supplied by many commercial OCR systems. Latent conditional independence (LCI) models perform better on this task, in our experience, than naive uniform thresholding methods. Given a sufficiently large and representative dataset of OCR (errorful) output and manually proofed (correct) text, we can automatically infer LCI models that exhibit a useful degree of reliability. A collaboration between a PARC research group and a Xerox legacy conversion service bureau has demonstrated that such models can significantly improve the productivity of human proofing staff by triaging -- that is, selecting to bypass manual inspection -- pages whose estimated OCR accuracy exceeds a threshold chosen to ensure that a customer-specified per-page accuracy target will be met with sufficient confidence. We report experimental results on over 1400 pages. Our triage software tools are running in production and will be applied to more than 5 million pages of multi-lingual text.
Periodic surface structure bifurcation induced by ultrafast laser generated point defect diffusion in GaAs (2016)

The formation of high spatial frequency laser induced periodic surface structures (HSFL) with period &lt;0.3 λ in GaAs after irradiation with femtosecond laser pulses in air is studied. We have identified a point defect generation mechanism that operates in a specific range of fluences in semiconductors between the band-gap closure and ultrafast-melt thresholds that produces vacancy/interstitial pairs. Stress relaxation, via diffusing defects, forms the 350–400 nm tall and ∼90 nm wide structures through a bifurcation process of lower spatial frequency surface structures. The resulting HSFL are predominately epitaxial single crystals and retain the original GaAs stoichiometry.
Expression of document structure in automatic layout (2006)

With the dynamic generation of documents and their presentation on various output devices, it is valuable to automatically adjust their layout and style. Measures for layout desirability have typically focused on document aesthetics (making the document look good). But other values are also important. This paper explores measures for the effectiveness with which style and layout convey the document's logical structure. This primarily contributes to the document's ease of use. The measures described are the group identity, separability and distinguishablity of elements. These measures are defined as combinations of simpler, properties that are practical to calculate.
Motionless-head parallel readout optical-disk system (1993)

The design, analysis, and feasibility of a novel motionless-head parallel readout optical-disk system are presented. The system is designed to read data blocks distributed radially on the disk's active surface, and it has the unique advantage that no mechanical motion of the head is required for fast access, focusing, or tracking. Data access is achieved solely through the disk rotation, and the entire memory can be read in one rotation. In principle, this permits a data rate of up to 1 Gbyte/s. The data blocks are one-dimensional Fourier-transform computer-generated holograms, each reconstructing one column of a two-dimensional output image. Owing to the information redundancy and shift invariance properties of Fourier-transform holograms, tracking and focusing servo requirements are eliminated. A holographic encoding method is developed to produce high signal-to-noise ratio reconstructions and to reduce significantly the radial alignment requirements of the recorded data bits. The optical readout system consists of only three cylindrical lenses. Two of these may be replaced by a single hybrid diffractive-refractive optical element for easier system alignment and better optical performance, i.e., reduced aberrations and improved resolution. The throughputs and retrieval times of this parallel readout optical-disk system make it well suited to a variety of parallel computing architectures, including a high-performance optoelectronic associative memory [Proc. Soc. Photo-Opt. Instrum. Eng. 1347, 86 (1990)].
ChemInform Abstract: NEUROLEPTIC 4‐ARYLTETRAHYDROPYRROLO(3,4‐B)INDOLES (1980)

Abstract Auf dem im Formelschema angegebenen Weg wirdhdas N‐Arylindolderivat (VI) hergestellt.
Model-based personalization scheme of an artificial pancreas for Type 1 diabetes applications (2013)

Automated controllers designed to regulate blood glucose concentrations in people with Type 1 diabetes mellitus (T1DM) must avoid hypoglycemia (blood glucose <;70 mg/dl) while minimizing hyperglycemia (>180 mg/dl), a challenging task. In this paper, a model-based control design approach with a personalized scheme based on readily available clinical factors is applied to a linearized control-relevant model of subject insulin-glucose response profiles. An insulin feedback strategy is included with specific personalization settings and variations in a tuning parameter, τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> . The control strategy is challenged by an unannounced meal disturbance with 50 g carbohydrate content. A set of metrics are introduced as a method of evaluating the performance of different controllers. In-silico simulations of ten subjects in the Food and Drug Administration accepted Universities of Virginia and Padova metabolic simulator indicate that the personalization strategy with a τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> setting of 270 minutes gives very good controller performance. Post-prandial glucose concentration peaks of 183 mg/dl were achieved with 97% of the total simulation time spent within a safe glycemic zone (70-180 mg/dl), without hypoglycemic incidents and without requiring a time-consuming model identification process.