gebhart/patrepeval huggingface dataset:
Mutation Analysis of the 5′ Untranslated Region of the Cold Shock <i>cspA</i> mRNA of <i>Escherichia coli</i> (1999)

The mRNA for CspA, a major cold shock protein in Escherichia coli, contains an unusually long (159 bases) 5' untranslated region (5'-UTR), and its stability has been shown to play a major role in cold shock induction of CspA. The 5'-UTR of the cspA mRNA has a negative effect on its expression at 37 degrees C but has a positive effect upon cold shock. In this report, a series of cspA-lacZ fusions having a 26- to 32-base deletion in the 5'-UTR were constructed to examine the roles of specific regions within the 5'-UTR in cspA expression. It was found that none of the deletion mutations had significant effects on the stability of mRNA at both 37 and 15 degrees C. However, two mutations (Delta56-86 and Delta86-117) caused a substantial increase of beta-galactosidase activity at 37 degrees C, indicating that the deleted regions contain a negative cis element(s) for translation. A mutation (Delta2-27) deleting the highly conserved cold box sequence had little effect on cold shock induction of beta-galactosidase. Interestingly, three mutations (Delta28-55, Delta86-117, and Delta118-143) caused poor cold shock induction of beta-galactosidase. In particular, the Delta118-143 mutation reduced the translation efficiency of the cspA mRNA to less than 10% of that of the wild-type construct. The deleted region contains a 13-base sequence named upstream box (bases 123 to 135), which is highly conserved in cspA, cspB, cspG, and cspI, and is located 11 bases upstream of the Shine-Dalgarno (SD) sequence. The upstream box might be another cis element involved in translation efficiency of the cspA mRNA in addition to the SD sequence and the downstream box sequence. The relationship between the mRNA secondary structure and translation efficiency is discussed.
Effect of acetylene concentration and thermal ramping rate on the growth of spin-capable carbon nanotube forests (2012)

Spin-capable multiwalled carbon nanotube (MWCNT) forests that can form webs, sheets, and yarns provide a promising means for advancing various technologies. It is necessary to understand the critical factors to grow spin-capable carbon nanotubes (CNTs) in a repeatable fashion. Here we show how both the spinning capability and morphology of MWCNT forests are significantly changed by controlling the C2H2 concentration and ramp rate of temperature. The acetylene gas flow was varied in the range of 0.25–6.94% by volume. The MWCNTs grown at C2H2 concentrations between 1.47–3.37% are well-aligned and become spin-capable. The well-aligned forests have higher areal density and shorter distance between CNTs. The thermal ramp rate was also changed from 30 °C/min to 70 °C/min. A specific range of thermal ramp rate is also required to have the suitably sized nanoparticles with sufficient density resulting in higher CNT areal density for spinnable MWCNTs. A ramp rate of 50 °C/min forms suitable sized nanoparticles with sufficient density to produce CNT forests with a higher areal density and a shorter tube spacing.
Multifunctional Hybrid Three‐dimensionally Woven Scaffolds for Cartilage Tissue Engineering (2010)

The successful replacement of large-scale cartilage defects or osteoarthritic lesions using tissue-engineering approaches will likely require composite biomaterial scaffolds that have biomimetic mechanical properties and can provide cell-instructive cues to control the growth and differentiation of embedded stem or progenitor cells. This study describes a novel method of constructing multifunctional scaffolds for cartilage tissue engineering that can provide both mechanical support and biological stimulation to seeded progenitor cells. 3-D woven PCL scaffolds were infiltrated with a slurry of homogenized CDM of porcine origin, seeded with human ASCs, and cultured for up to 42 d under standard growth conditions. These constructs were compared to scaffolds derived solely from CDM as well as 3-D woven PCL fabric without CDM. While all scaffolds promoted a chondrogenic phenotype of the ASCs, CDM scaffolds showed low compressive and shear moduli and contracted significantly during culture. Fiber-reinforced CDM scaffolds and 3-D woven PCL scaffolds maintained their mechanical properties throughout the culture period, while supporting the accumulation of a cartilaginous extracellular matrix. These findings show that fiber-reinforced hybrid scaffolds can be produced with biomimetic mechanical properties as well as the ability to promote ASC differentiation and chondrogenesis in vitro.
Integral Foam Moulding of Light Metals (2006)

Integral foam moulding (IFM) is an economical way to produce castings with integrated cellular structure, i.e. a solid skin and a foamed core. IFM has been known for polymers for more than four decades and is well established in industrial production. Polymer integral foam parts are accepted as a material system with own properties which simplifies designs, reduces production costs and weight, and increases stiffness and overall strength. On the other hand, integral foam moulding for metals is a new field of research. The development of metal based integral foam moulding processes at WTM moves along analogous paths as that of polymers by transferring and adapting successful moulding technologies for polymer integral foam to metals. Two moulding techniques for metal integral foam are presented, a low and a high pressure process. In the low pressure process, the molten metal charged with blowing agent is injected into a permanent steel mould without completely filling it. In this case, the mould gets eventually filled by foam expansion.In the high pressure process foaming is initiated by expansion of the mould cavity after it has been filled completely with the mixture of the metal melt and the blowing agent. The moulded parts are characterized with respect to their cellular structure, density profile and pore size distribution. Mechanical properties such as stiffness and damping behaviour are discussed.
Low temperature soldering (2002)

Low temperature soldering may reduce the cost for surface mount electronic assembly by using low cost electronic components and substrate materials. It also provides options for step soldering, and reduces the risk of thermally induced damages. A vast amount of Sn-Pb-Bi-In alloys are available for any given melting temperature (liquidus) between 50/spl deg/C and 183/spl deg/C. Currently available water clean or no-clean fluxes, however, are not suitable for low temperature soldering, because they are activated at temperature higher than 150/spl deg/C. Two solderability test methods were used to evaluate the newly developed fluxes for low temperature soldering: (a) spreading test to compare the relative strength of the fluxes, and (b) wetting balance to determine the activation temperature of the fluxes. The mechanical properties (shear strength, creep, isothermal and thermal fatigue) of several common low temperature solders were determined. Prototypes of PCBs assembled with several low temperature solders were successfully built and passed typical product qualification tests. Potential problems for low temperature soldering are the poor adhesion strength of the low temperature solders to Alloy 42 leaded components, and exceptional grain growth and early thermal failure when 58Bi-42Sn was used to solder on Sn-Pb surface.
Large-Scale Production of Single-Walled Carbon Nanotubes Using Ultrafast Pulses from a Free Electron Laser (2002)

We report the first use of ultrafast (subpicosecond) laser pulses for large-scale production of single wall carbon nanotubes (SWNT's) by the pulsed laser vaporization (PLV) technique. Very high production rates were achieved; using only 20% of the nominal average power of the 1 kW Jefferson Lab free electron laser (Jlab FEL), carbon soots rich in high quality bundles of SWNT's were produced at ∼1.5 g/h. Accordingly, a novel PLV geometry employing a spinning target and a sonic shearing jet of 1000 °C argon was developed to accommodate the highly energetic Jlab FEL ablation plume. Samples were characterized by scanning electron microscope, atomic force microscopy, transmission electron microscopy, temperature programmed oxidation, and Raman spectroscopy.
A spatial-temporal charging load forecast and impact analysis method for distribution network using EVs-traffic-distribution model (2017)

A method for the forecast of charging load of electric vehicles (EVs) under “EVs-Traffic-Distribution” (ETD) system was developed to precisely manifest the spatial-temporal characteristics of large scale EV charging load in urban area and to evaluate the impact of the load on urban distribution network. An EV model with charging characteristics, a traffic network model with urban road topology and a classic velocity-capacity model were introduced to provide the spatial-temporal driving routes and velocity. With the above information, origin-destination (OD) analysis was used to simulate the mobility of each EV. And, Monte Carlo simulation was conducted to estimate the EVs’ spatial-temporal charging load characteristics over a day. By allocating the charging load of each EV to the nearest node in the distribution network, sequential power flow was conducted to evaluate the impact of charging load on the distribution network. A 29-node urban area combined with the geographic information and a 33-node distribution system was selected to validate the proposed method. Simulation results demonstrate its effectiveness.
Miniaturized flow cell with pneumatically-actuated vertical nanoconfinement for single-molecule imaging and manipulation (2018)

Convex Lens-induced Confinement (CLiC) is a single-molecule imaging technique that uses a deformable glass flow cell to gently trap, manipulate, and visualize single molecules within micro- and nano-structures, to enable a wide range of applications. Here, we miniaturize the CLiC flow cell, from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>25</mml:mn> <mml:mo>×</mml:mo> <mml:mn>25</mml:mn></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>3</mml:mn> <mml:mo>×</mml:mo> <mml:mn>3</mml:mn> <mml:mspace></mml:mspace> <mml:msup><mml:mtext>mm</mml:mtext> <mml:mn>2</mml:mn></mml:msup> </mml:math> and introduce pneumatic control of the confinement. Miniaturization of the flow cell improves fabrication throughput by almost two orders of magnitude and, advantageous for pharmaceutical and diagnostic applications where samples are precious, significantly lowers the internal volume from microliters to nanoliters. Pneumatic control of the device reduces the confinement gradient and improves mechanical stability while maintaining low autofluorescence and refractive index-matching with oil-immersion objectives. To demonstrate our "mini CLiC" system, we confine and image DNA in sub-50 nm nanogrooves, with high DNA extension consistent with the Odijk confinement regime.
PREPARATION OF LARGE-PARTICLE-SIZE MONODISPERSE LATEXES IN SPACE: POLYMERIZATION KINETICS AND PROCESS DEVELOPMENT (1984)

ABSTRACT Monodisperse polystyrene latexes are prepared by seeded emulsion polymerization; however, sizes larger than 2μm are difficult to prepare because of the creaming and settling of the particles, and their sensitivity to mechanical shear. Preparation in space would obviate the creaming and settling, and allow agitation just sufficient for good heat transfer and mixing. Three polymerizations yielding 3-5μm size particles were carried out successfully on the third flight of the “Columbia” launched March 22, 1982; however, four polymerizations yielding sizes up to 10μm on the fourth flight launched June 27, 1982, were incomplete owing to apparatus malfunction. The results of these polymerizations and the prospects of developing a preparative space process are reviewed
A high-efficiency broadband HF wire-antenna system (2000)

The purpose of this antenna design is to provide an efficient, broadband, wire-antenna system for RF communications. The benefits of the antenna include a single integrated antenna system for total band coverage, high system efficiency across the operating band, the capability to transmit and receive multiple signals instantaneously, and simple mechanical assemblies. The antenna design comprises various configurations of multiple transceivers, connected to a set of RF filters and associated impedance-matching networks, which are used to excite a plurality of trapped-antenna elements. The antenna system offers control over the antenna's directivity and the antenna's driving-point impedance by using sub-band systems, as defined by a series of RF filters and traps that divide the physical antenna element into varying radiating lengths. Continuous coverage over the entire frequency band of interest is achieved by using different physical antenna elements for adjacent sub-bands. The utilization of sub-bands reduces the impedance-matching network requirements, and helps to more efficiently radiate energy over the entire frequency band of interest. The resultant higher antenna system efficiencies allow for moderate and feasible performance specifications for transmitters, receivers, and matching-network components. The design can utilize various configurations and orientations of monopoles, dipoles, associated arrays, and RF traps.
Palladium(II)-Catalyzed Isospecific Alternating Copolymerization of Aliphatic .alpha.-Olefins with Carbon Monoxide and Isospecific Alternating Isomerization Cooligomerization of a 1,2-Disubstituted Olefin with Carbon Monoxide. Synthesis of Novel, Optically Active, Isotactic 1,4- and 1,5-Polyketones (1995)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPalladium(II)-Catalyzed Isospecific Alternating Copolymerization of Aliphatic .alpha.-Olefins with Carbon Monoxide and Isospecific Alternating Isomerization Cooligomerization of a 1,2-Disubstituted Olefin with Carbon Monoxide. Synthesis of Novel, Optically Active, Isotactic 1,4- and 1,5-PolyketonesZhaozhong Jiang and Ayusman SenCite this: J. Am. Chem. Soc. 1995, 117, 16, 4455–4467Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://pubs.acs.org/doi/10.1021/ja00121a003https://doi.org/10.1021/ja00121a003research-articleACS PublicationsRequest reuse permissionsArticle Views697Altmetric-Citations168LEARN 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
Cosupported Tandem Catalysts for Production of Linear Low-Density Polyethylene from an Ethylene-Only Feed (2016)

Linear low-density polyethylene (LLDPE) is produced from an ethylene-only feed over a tandem catalyst system consisting of a phenoxy–imine titanium trimerization catalyst and a silylene-linked cyclopentadienyl/amido titanium polymerization catalyst cosupported on the same methylaluminoxane/silica particles. The level of 1-hexene incorporation can be controlled by varying the ethylene pressure.
<title>Luminescent Solar Concentrators</title> (1980)

A type of solar concentrator for photovoltaics utilizing light pipe trapping of luminescence is described. Total collector efficiencies of 3. 2% have been measured, and efficiencies of 10% appear theoretically possible. The photodegradation lifetime of the dyes presently used is about one year under optimal conditions.
<title>Micromachined ultrasonic transducers for air-coupled nondestructive evaluation</title> (1999)

Conventional methods of ultrasonic non-destructive evaluation (NDE) use liquids to couple sound waves into the test samples. This either requires immersion of the parts to be examined or the use of complex and bulky water squirting systems that must be scanned over the structure. Air-coupled ultrasonic systems eliminate these requirements if the losses at air-solid interfaces are tolerable. Micromachined capacitive ultrasonic transducers (cMUTs) have been shown to have more than 100 dB dynamic range when used in the bistatic transmission mode. In this paper, we present results of a pitch-catch transmission system using cMUTs that achieves a 103 dB dynamic range. Each transducer consists of 10,000 silicon nitride membranes of 100 micrometers diameter connected in parallel. This geometry result in transducers with a resonant frequency around 2.3 MHz. These transducers can be used in transmission experiments at normal incident to the sample or to excite and detect guided waves in aluminum and composite plates. In this paper we present ultrasonic defect detection results from both through transmission and guided Lamb wave experiments in aluminum and composite plates, such as those used in aircraft.
The blood-brain barrier: an engineering perspective (2013)

It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich's first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and this selective permeability remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore, advances in our understanding of the structure and function of the blood-brain barrier are key to developing effective treatments for a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex, dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.
Spectral Kernel Methods for Clustering (2002)

In this paper we introduce new algorithms for unsupervised learning based on the use of a kernel matrix. All the information required by such algorithms is contained in the eigenvectors of the matrix or of closely related matrices. We use two different but related cost functions, the Alignment and the 'cut cost'. The first one is discussed in a companion paper [3], the second one is based on graph theoretic concepts. Both functions measure the level of clustering of a labeled dataset, or the correlation between data clusters and labels. We state the problem of unsupervised learning as assigning labels so as to optimize these cost functions. We show how the optimal solution can be approximated by slightly relaxing the corresponding optimization problem, and how this corresponds to using eigenvector information. The resulting simple algorithms are tested on real world data with positive results.
A New Compton Densitometer for Measuring Pulmonary Edema (1986)

Pulmonary edema (P.E.) is the pathological increase of extravascular lung water found most often in patients with congestive heart failure and other critically ill patients who suffer from intravenous fluid overload. The chest x-ray, the standard method for validating the presence of P.E., is neither quantitative nor sensitive. A non-invasive lung density monitor that is accurate, easily portable, safe and inexpensive is needed for clinical use. To deal with the problem of attenuation along the beam paths, previous gamma-ray techniques require simultaneous measurement of transmitted and scattered beams. Since multiple scattering is a strong function of the density of the scattering medium and the mass distribution within the detection geometry, there will be inherent uncertainties in the system calibration unless it is performed on a body structure closely matched to that of each individual patient. Other researchers who have employed Compton scattering techniques generally used systems of extended size and detectors with poor energy resolution. This has resulted in significant systematic biases from multiply-scattered photons and larger errors in counting statistics at a given radiation dose to the patient. We are proposing a patented approach in which only backscattered photons are measured with a high-resolution HPGe detector in a compact system geometry. By proper design and a unique data extraction scheme, effects of the variable chest wall on lung density measurements are minimized.
Improved fiberoptic spectrophotometer (1985)

The present invention allows for accurate spectrophotmetric comparison of the Raman scattering from a sample gas with the Raman scattering from a known gas via a novel fiber optic network. The need for complicated electronic of optical circuit balancing, control, or error compensation circuitry is eliminated. The laser cavity is split into two regions, one of which houses the plasma discharge and produces laser power, and the other of which is adapted to house tubes containing the gas samples. Light from the laser source is beamed simultaneously through samples of the reference gas and the unknown gas, and Raman-scattered light is emitted. The Raman-scattered light from the known and unknown mixtures is then alternately passed through a fiber optic network where the various wavelengths are spatially mixed. The mixed light is then passed into a system of light detectors, each of which are adapted to measure one of the wavelengths of light representing a constituent element of the gases. When the test is complete, each gas sample can be assigned a Raman-scattered profile from the data consisting of the ratios each of the constituent elements bear to each other. (LEW)
Nanowires of four epitaxial hexagonal silicides grown on Si(001) (2002)

Epitaxial self-assembled silicide nanowires can be grown on Si (001) if the magnitude of the lattice mismatch between epilayer and substrate is large along one crystal axis and small along the perpendicular axis. This phenomenon is illustrated with four examples: ScSi2, ErSi2, DySi2, and GdSi2, which have lattice mismatches of −4.6%, 6.3%, 7.6%, and 8.9%, respectively, along one of the Si 〈110〉 directions and mismatches of 0.8%, −1.6%, −0.1%, and 0.8%, respectively, along the perpendicular Si〈110〉 direction. The resulting self-assembled nanowires have widths and heights in the range of 3–11 and 0.2–3 nm, depending on the lattice mismatches. The average lengths of the nanowires are in the range 150–450 nm, and are determined primarily by kinetic issues. The epitaxial growth of silicide nanowires should prove interesting to those studying quasi-one- dimensional systems.