gebhart/patrepeval huggingface dataset:
Organocatalytic Asymmetric Direct α-Alkynylation of Cyclic β-Ketoesters (2006)

The first organocatalytic enantioselective direct alpha-alkynylation of beta-ketoesters and 3-acyl oxindoles is described. It is demonstrated that activated beta-halo-alkynes undergo nucleophilic acetylenic substitution catalyzed by chiral phase-transfer compounds to afford the alkynylated products in high yields and excellent enantioselectivities. The potential of the reaction is first demonstrated for various alkynylating reagents having chloride and bromide as the leaving groups and substituents such as allyl and alkyl esters, amides, ketones, and sulfones. These reactions proceed with 74-99% yield and 88-97% ee. Then the scope in nucleophile is demonstrated for a large number of cyclic beta-ketoesters with various ring-sizes and for oxindoles as well. The corresponding optically active products are formed in high yields and with enantioselectivities up to 98% ee. The procedure allows for the stereocontrolled attachment of an ethynyl unit in the alpha-position to the carbonyl compound by facile removal of the activating group, and this has been demonstrated for a number of the optically active allyl esters. Furthermore, the synthesis of optically active 1,4-enynes is also shown. The isolation and characterization by X-ray analysis of the catalyst with p-nitrophenolate as the counterion allowed us to propose a model of the catalyst-substrate intermediate which might account for the observed enantioselectivity of the organocatalytic enantioselective alpha-alkynylation reaction. Furthermore, it is suggested that this intermediate is also the reactive species for a number of other electrophiles adding to beta-ketoesters giving enantioselectivities in the range of 90-98% ee.
Hemoglobin switching in sheep. Isolation of the fetal gamma-globin gene and demonstration that the fetal gamma- and adult beta A-globin genes lie within eight kilobase segments of homologous DNA. (1981)

A recombinant DNA library of sheep genomic DNA fragments inserted into the bacteriophage vector, Charon 4A, was screened by plaque hybridization with a probe for sheep gamma-globin gene sequences. Three clones containing overlapping segments of DNA, the total length of which was 25 kb, were identified; each included all or a part of the same globin gene. Nucleotide sequencing of substantial portions of the globin gene in one clone, lambda S gamma G31, and of the gene in a previously isolated recombinant, lambda S beta AG21, established that the genes in these recombinants encoded for the gamma- and beta A-globin genes of sheep, respectively. Features characteristic of globin genes in other species that were identified in both genes included a sequence, ATAAAA, 30 nucleotides from the presumed site of initiation of transcription, a region of "capping homology," two introns at positions corresponding to amino acids 29-30 and 103-104 and the polyadenylation sequence, AATAAA, in the 3' untranslated region. Electron microscopic analysis of heteroduplexes formed between lambda S gamma G31 and lambda S beta AG21 revealed that the gamma and beta A genes of sheep lie within segments of homologous DNA at least 8 kb in length within which were identified small regions of nonhomology both 5' and 3' to the genes.
A versatile array fed reflector antenna-Part A: reception (2003)

An original antenna subsystem for the European data-relay satellite using a deployable reflector associated to an array feed is described. The reflector pattern is deflected by amplitude and phase control of the elements in the feed array. The general operating principle of the antenna and receiver hardware are described. The same antenna can be used for transmit and receive by a double-patch microstrip element. The results of this study have demonstrated the feasibility of this antenna concept from an overall system point of view (electrical, mechanical, thermal platform, and launch vehicle compatibility). A detailed mass budget of the final design is given for four receive channels, two transmit channels, and an umbrella mesh antenna.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Structural evaluation of defects in β-Ga<sub>2</sub>O<sub>3</sub> single crystals grown by edge-defined film-fed growth process (2016)

Abstract We have structurally evaluated β-Ga 2 O 3 crystals grown by edge-defined film-fed growth process using etch pitting, focused ion beam scanning ion microscopy, transmission electron microscopy, and related techniques. We found three types of defects: arrays of edge dislocations corresponding to etch pit arrays on -oriented wafers, platelike nanopipes corresponding to etch pits revealed on the (010)-oriented wafers, and twins including twin lamellae.
Theoretical basis for genetic linkage analysis in autotetraploid species (2004)

Linkage analysis in autotetraploid species has been an historical challenge in quantitative genetics theory and is a stumbling block that urgently needs to be removed in the rapidly emerging genome research on this species, such as cultivated potato. This article presents theory of a full model of tetrasomic linkage and develops a statistical framework for the linkage analysis. The model considers both double reduction and recombination, the most essential features of tetrasomic inheritance with linked loci, whereas the statistical method takes appropriate account of the major complexities in analyzing both dominant and codominant molecular marker data during map reconstruction in tetraploid species. These complexities include the problems arising from multiple dosage of allelic inheritance, the null allele, allelic segregation distortion, mixed bivalent and quadrivalent pairing in meiosis, and incomplete information of marker phenotype data. The theoretical analysis established the relationship between the coefficients of double reduction at linked loci, which is essential in the present tetrasomic linkage analysis and in assessing the impact of double reduction on the evolution of tetraploid populations. The statistical method, based on the combination of theoretical analysis and a computer-based algorithm, provided analytical tools for predicting the maximum-likelihood estimates of the model parameters. A simulation study showed the feasibility of a practical implementation of the method, detailed the procedure of the analysis, validated the power and reliability in the parameter estimation, and compared the present method with those proposed in the current literature.
Joint OSNR and Interchannel Nonlinearity Estimation Method Based on Fractional Fourier Transform (2017)

We propose a novel joint optical signal noise ratio (OSNR) and interchannel nonlinearity (NL) estimation method by fractional Fourier transformation of linear-frequency modulation (LFM) signal. In our method, LFM signal acts as time domain pilot in front of the payload. Our method of OSNR estimation is insensitive to nonlinear noise of optical fiber. Lower OSNR estimation error is also achieved in comparison with differential pilot method. The interchannel NL measurement procedures are also simplified compared with previous work. We also provide a scientific way to calculate the reference interchannel NL. The interchannel NL estimation error of our method is lower than 1 dB for 9 channels transmission after 10 spans with launch power from 10 to 14 dBm.
Anomalous Mobility Effects in Some Semiconductors and Insulators (1962)

The Hall mobility in semiconductors and insulators can be greatly affected by inhomogeneous impurity distributions. This is due to the formation of large space-charge regions surrounding local inhomogeneities. The scattering cross section of Coulombic centers can be increased by over an order of magnitude when inhomogeneously distributed. The mobility resulting from scattering from inhomogeneities varies roughly as T−½ and decreases with decreasing carrier concentration. Assuming that inhomogeneities can occur frequently, various anomalous Hall mobility effects can be explained, such as mobility ``killers'' in GaAs, InAs, and InP; giant scattering cross sections in GaAs, InP, CdS, and CdSe; abnormally low mobilities in compensated InAs; and low mobilities in ZnO containing precipitates.
Transcriptional Regulation of the Human GnRH II Gene Is Mediated by a Putative cAMP Response Element (2001)

Human neuronal medulloblastoma cells (TE-671) were recently demonstrated to express the two forms of GnRH (GnRH-I and GnRH-II). We have used this cell line as a model system to demonstrate regulation of the human GnRH-II gene by cAMP. RT-PCR and Southern hybridization demonstrated that GnRH-II mRNA is strongly up-regulated ( approximately 6-fold) by (Bu)(2)cAMP. The concentration of GnRH-II that was released into the medium of TE-671 cells treated with the cAMP analog was significantly higher than that of the untreated cells. TE-671 cells that were stimulated by (Bu)(2)cAMP demonstrated morphological changes and strong immunoreactive GnRH-II staining in part of the cell population. After screening of the GnRH-II promoter sequence, we identified a putative cAMP response element consensus site. The GnRH-I and GnRH-II promoters were isolated by PCR using human genomic DNA and cloned into the luciferase reporter plasmid. By measuring the basal activity of the promoters that were transfected to TE-671 cells, we found a much stronger basal activity of the GnRH-II promoter compared with that of GnRH-I. Treatment of transfected TE-671 cells with (Bu)(2)cAMP resulted in a strong activation of the GnRH-II promoter compared with a modest activation of the GnRH-I promoter. To determine the functionality of this putative cAMP response element site, we mutated this site. TE-671 cells that were transfected with cAMP response element mutant constructs demonstrated a diminished basal activity of the GnRH-II promoter. Treatment of the transfected cells with the cAMP analog demonstrated a decrease to 0.03% of the activity of the mutated promoter compared with that of the wild type. These results clearly demonstrate the importance of the putative cAMP response element site for the basal activity as well as for induction of the GnRH-II promoter by cAMP.
The quantum cascade laser: A versatile high-power semiconductor laser for mid-infrared applications (2005)

Since its invention at Bell Labs in the mid-nineties, the quantum cascade laser (QCL) has evolved rapidly to become a viable commercial alternative to other solid-state mid-infrared light sources. QCLs are compact, high-power, wavelength-agile laser devices that are ideally suited for mid-infrared applications such as chemical sensing and free-space telecommunications. This paper summarizes our recent progress in QCL technology, with a particular emphasis on device design and fabrication. The current state-of-the-art in performance of InP lattice-matched QCL is reviewed. In order to expand the functionality of QCLs, new materials and device concepts are being explored. In particular, nonlinear light generation in QCLs is discussed in detail. The experimental results confirm the potential of nonlinear QCLs to extend the wavelength range of InP-based devices. Ongoing efforts to improve the fabrication of InP-based QCLs and to develop new QCL materials are presented.
Pteroenone: A Defensive Metabolite of the Abducted Antarctic Pteropod Clione antarctica (1995)

ADVERTISEMENT RETURN TO ISSUEPREVArticlePteroenone: A Defensive Metabolite of the Abducted Antarctic Pteropod Clione antarcticaWesley Y. Yoshida, Patrick J. Bryan, Bill J. Baker, and James B. McClintockCite this: J. Org. Chem. 1995, 60, 3, 780–782Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published inissue 1 February 1995https://pubs.acs.org/doi/10.1021/jo00108a057https://doi.org/10.1021/jo00108a057research-articleACS PublicationsRequest reuse permissionsArticle Views272Altmetric-Citations65LEARN 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-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Image-Guided Surgery of Primary Breast Cancer Using Ultrasound Phased Arrays (2004)

Abstract : Recent developments of piezocomposite transducer technology have lead to the development of new generation of ultrasound phased arrays with imaging and therapeutic capabilities. These dual-mode arrays provide an ideal nonionizing noninvasive tool for the treatment of primary breast cancer. This project investigates the thresholds for tissue damage under a variety of exposure conditions to high-intensity focused ultrasound from dual-mode arrays. In addition, we investigate new imaging techniques for enhanced visualization of thermal lesions in tissue media. These investigations are carried on ex-vivo animal tissue and in-vitro breast tissue and will lead to the design of a new generation of phased array drivers capable of supporting both the imaging and therapeutic requirements of the dual-mode system. During the second year of the grant, we have focused on the complete characterization of the imaging capabilities of the dual-mode array prototype for visualization of lesions in ex vivo tissue. We have also compared these imaging results with those obtained using a commercially available diagnostic scanner. The results validated the dual-more array approach and allowed us to finalize the design of the real-time data collection and beamforming algorithm. We are on track towards implementing a real-time dual-mode system suitable for in vivo animal experiments.
SQL Test Suite goes online (1997)

Does your relational database speak SQL fluently? It's easy to find out, because the SQL (Structured Query Language) Test Suite is now free on the Web. SQL is the standard that lets DBMS products from different vendors interoperate. It defines common data structures (tables, columns, views, and so on) and provides a data manipulation language to populate, update, and query those structures. Accessing structured data with SQL is quite different from searching the full text of documents on the Web. Structured data in the relational model means data that can be represented in tables. Each row represents a different item, and the columns represent various attributes of the item. Columns have names and integrity constraints that specify valid values. Because the column values are named and represented in a consistent format, you can select rows precisely, on the basis of their contents. This is especially helpful in dealing with numeric data. You can also join data from different tables on the basis of matching column values. It is possible to do useful types of analysis too, listing items that are in one table and are missing, present, or have specific attributes in a related table. You can extract from a large table precisely those rows of interest, regroup them, and generate simple statistics on them.
Ultrastructural study of upper surface layer in rat mandibular condylar cartilage by quick-freezing method. (2004)

The purpose of the present study is to clarify native ultrastructures of upper surface layers of the rat mandibular condylar cartilage in vivo by a quick-freezing method. The mandibular cartilaginous tissues were removed with their articular discs attached without opening the lower joint cavity. The specimens were processed for light microscopy, transmission or scanning electron microscopy. Deep-etching replica membranes were also prepared after the routine quick-freezing method. The upper surface layer was well preserved by the quick-freezing method. The cartilaginous tissues, which were fixed without opening their articular discs, appeared to keep better morphology than those after opening them. The upper surface layer was thicker than the corresponding layer as reported before. It consisted of atypical extracellular matrices with lots of apparently amorphous components, which were distributed over typical collagen fibrils, by conventional electron microscopy. As revealed with the replica membranes, it also consisted of variously sized filaments and tiny granular components localized on the typical collagen fibrils. A pair of stereo-replica electron micrographs three-dimensionally showed compact filaments within the upper surface layer. The quick-freezing method was useful for keeping native ultrastructures of the fragile upper surface layer in the mandibular condylar cartilage, which may be functionally important to facilitate smooth movement of the temporomandibular joint.
A scalable, high-performance customized priority queue (2014)

Priority queues are abstract data structures where each element is associated with a priority, and the highest priority element is always retrieved first from the queue. The data structure is widely used within databases, including the last stage of a merge-sort, forecasting read-ahead I/O to stream data for the merge-sort, and replacement selection sort. Typical software implementations use a balanced binary tree-based structure, providing O(log N) time for both enqueue and dequeue operations. To improve the performance, we propose several scalable and high-speed FPGA-based implementations of a priority queue. Our insight is that the above listed applications primarily use priority queues through “replace” operations, which remove the highest priority element and place a new element into the queue. Thus, our designs are customized for this operation, allowing for a simple and scalable architecture. We implement three priority queue designs, including use of a register-based array, register-based tree, and BRAM-based tree, which have different benefits and trade-offs of throughput, frequency, and maximum size. More importantly, all designs achieve O(1) time between replace operations. To incorporate the best aspects of our designs, we propose a Hybrid Priority Queue (H-PQ), which combines a register-based array with multiple BRAM-based trees. This design provides, on average, very fast access times to the top items in the queue (through the register-based array), while scaling to large priority queue sizes (through the BRAM-based trees). In our evaluations, we find that H-PQ achieves 4.3x speedup and 21.5x energy efficiency, compared with the Xeon CPU implementations.
Genetic Algorithms for Calibrating Water Quality Models (1998)

The genetic algorithm (GA) is used as an optimization tool to estimate water quality model parameters in a calibration scenario. The GA is found to be a useful calibration tool, capable of providing least-squares parameter estimates while incorporating field observations as constraints and accumulating useful information about the response surface. Because the GA provides a directed, randomized search using a population of points, a database of information about the response surface, parameter correlation, and objective function sensitivity to model parameters is obtained. Synthetic data with and without error are used initially to investigate the potential of the GA for model calibration applications. A case study is then carried out to confirm GA performance with field data. Constraints are included successfully in the GA search using either a penalty function or a special decoding operation. However, results show that the GA with the penalty function outperforms the GA with the decoder. Furthermore, parameter estimation is found to be improved by the inclusion of multiple-response data. For ill-posed problems, the GA provides several parameter estimates, all performing equally well mathematically.
HIGH FREQUENCY ELECTRICAL TRANSPORT MEASUREMENTS OF NIOBIUM SNS JOSEPHSON JUNCTION ARRAYS AND NIOBIUM THIN FILMS WITH NANOSCALE SIZE MAGNETIC DOT ARRAY (2003)

In this dissertation, measurements on two different niobium (Nb) based systems, namely superconductor-normal-metal-superconductor (SNS) Josephson junction arrays (JJA), and thin Nb films with nanoscale size magnetic dot arrays, are presented.Without high frequency (rf) signals at nearly zero magnetic field, these measurements show similarities for the two systems.These similarities are explained by proposing that very close to the critical temperature (T c ) of the Nb film sample, the stray magnetic field of the dots reduces the superconductivity in the film to make it a superconductor-weaker-superconductor-superconductor (SS'S) JJA.With rf signals, their dc-voltage-current characteristics (VI's) show the appearance of constant voltage steps known as Shapiro steps.For SNS-JJA, the dependence of the width of the steps ( I n ) on the amplitude of the rf current (I rf ) is Bessel-function-like.The maximum width of the first step ([ I 1 ] MAX ) was found to increase as a function of rf frequency ( rf ) reaching a maximum for rf ~1.8 times the array's Josephson frequency ( c ).This maximum was maintained for rf >4.9 c .Also, in JJA with missing junctions, [ I n ] MAX was smaller, disappearing for rf ~ c .For Nb films near T c , no Bessel-function-like oscillations were observed for I n .Also, I 0 (or critical current, I c ) showed a maximum for I rf 0, contrary to what was found in SNS-JJA, falling to zero for higher I rf .This enhancement of I c with I rf was attributed to non-equilibrium superconductivity mechanisms near T c .Observation of higher order steps (n=1,2,3,etc) became evident only from the dynamic resistance (dV/dI)vs.V plots (where a step corresponds to a minima for this curve).The first step was most evident for I rf values that made I 0 =0.At these values, V 1 (the voltage that corresponded to the first minimum in the dV/dIvs.V curve) satisfied the Josephson relation V 1 =N(h/2e) rf , where N is the number of "junctions" in the direction of the current.At fixed rf , V 1 was found to increase with I rf .This result was interpreted as having more "junctions" participating in the step's formation, which was attributed to magnetic interactions among the dot's magnetic moments and with the I rf to minimize the total energy of the system.
Acoustic velocity logging at the McConnell nickel deposit, Sudbury area, Ontario: preliminary in situ measurements (1994)

An acoustic velocity logging probe has been used to acquire data on the seismic characteristics of the McConnell nickel deposit in the Sudbury area. Preliminary results indicate good velocity contrasts in the stratigraphic sequence associated with the massive sulphides. These velocity contrasts are related to the density and elastic properties of the rocks; density was measured in the same borehole with a density logging probe. One interesting observation is that the high density massive sulphides have low P-wave velocities relative to the host rocks. This is not a universally applicable condition because some massive sulphides in other areas being investigated have higher velocities. Full sonic waveforms were recorded and these will be further studied to extract S-wave velocities. The P- and S-wave velocity and amplitude logs will then be used to derive valuable geotechnical information.