gebhart/patrepeval huggingface dataset:
Highly enantioselective borane reduction of ketones catalyzed by chiral oxazaborolidines. Mechanism and synthetic implications (1987)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHighly enantioselective borane reduction of ketones catalyzed by chiral oxazaborolidines. Mechanism and synthetic implicationsE. J. Corey, Raman K. Bakshi, and Saizo ShibataCite this: J. Am. Chem. Soc. 1987, 109, 18, 5551–5553Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/ja00252a056https://doi.org/10.1021/ja00252a056research-articleACS PublicationsRequest reuse permissionsArticle Views16694Altmetric-Citations1282LEARN 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
Position-Dependent Methylation and Transcriptional Silencing of Transgenes in Inverted T-DNA Repeats: Implications for Posttranscriptional Silencing of Homologous Host Genes in Plants (1998)

Posttranscriptional silencing of chalcone synthase (Chs) genes in petunia transformants occurs by introducing T-DNAs that contain a promoter-driven or promoterless Chs transgene. With the constructs we used, silencing occurs only by T-DNA loci which are composed of two or more T-DNA copies that are arranged as inverted repeats (IRs). Since we are interested in the mechanism by which these IR loci induce silencing, we have analyzed different IR loci and nonsilencing single-copy (S) T-DNA loci with respect to the expression and methylation of the transgenes residing in these loci. We show that in an IR locus, the transgenes located proximal to the IR center are much more highly methylated than are the distal genes. A strong silencing locus composed of three inverted T-DNAs bearing promoterless Chs transgenes was methylated across the entire locus. The host Chs genes in untransformed plants were moderately methylated, and no change in methylation was detected when the genes were silenced. Run-on transcription assays showed that promoter-driven transgenes located proximal to the center of a particular IR are transcriptionally more repressed than are the distal genes of the same IR locus. Transcription of the promoterless Chs transgenes could not be detected. In the primary transformant, some of the IR loci were detected together with an unlinked S locus. We observed that the methylation and expression characteristics of the transgenes of these S loci were comparable to those of the partner IR loci, suggesting that there has been cross talk between the two types of loci. Despite the similar features, S loci are unable to induce silencing, indicating that the palindromic arrangement of the Chs transgenes in the IR loci is critical for silencing. Since transcriptionally silenced transgenes in IRs can trigger posttranscriptional silencing of the host genes, our data are most consistent with a model of silencing in which the transgenes physically interact with the homologous host gene(s). The interaction may alter epigenetic features other than methylation, thereby impairing the regular production of mRNA.
Decreased Expression of Caveolin-1 and Altered Regulation of Mitogen-Activated Protein Kinase in Cultured Bovine Parathyroid Cells and Human Parathyroid Adenomas (2003)

Caveolins are key components of caveolae membranes. The calcium-sensing receptor (CaR) resides within caveolin-rich membrane domains in bovine parathyroid (PT) cells. Recent studies reported reduced CaR expression, and abnormal calcium-sensing in PT tumors. To examine this altered CaR signaling, we investigated ERK activation after CaR stimulation in human and bovine PT cells. In freshly prepared bovine PT cells, high extracellular calcium (Ca(2+)(0)) stimulates ERK1/2 phosphorylation, and activated ERK1/2 colocalizes with caveolin-1 at the plasma membrane but fails to translocate to the nucleus, and cell proliferation is low. In cultured bovine PT cells, CaR and caveolin-1 levels are reduced; activated ERK1/2 localizes in the cell periphery at 10 min and in the perinuclear and nuclear regions at 60 min after exposure to high Ca(2+)(0), and cell proliferation is increased. In PT cells from adenomas, there are high levels of caveolin-2, variably reduced caveolin-1, and hyperactivation of ERK1/2, which colocalizes with caveolin-1 in some cells, but localizes in the cytosol and nucleus in others. Finally, caveolin-1 negative human PT cells exhibit reduced suppressibility of PTH secretion by high Ca(2+)(0). Thus, CaR and caveolin-1 colocalize in PT cells, and reduced levels of caveolin-1 could participate in the abnormal cellular function and proliferation of cultured bovine PT cells and PT adenomas.
Seamless access to multiple wireless data networks. A wireless data network infrastructure at Carnegie Mellon University (1996)

In order to support mobile computing research, including the development of software which will allow seamless access to multiple wireless data networks, a wireless data network infrastructure is being built at Carnegie Mellon University. This infrastructure will allow researchers and other members of the campus community to use mobile computers to gain access to data networks while they are on-campus, or off-campus in the greater Pittsburgh area. The infrastructure will initially include two different types of wireless networks, a low-bandwidth wide area system and a high-bandwidth local area system, each of which will provide access to the campus computer network. Since the campus network is called "Andrew" (after Andrew Carnegie and Andrew Mellon), the new wireless infrastructure has been dubbed "Wireless Andrew". The article describes the Wireless Andrew infrastructure being built. An overview of the infrastructure and the characteristics of the two types of wireless networks used are presented. Each of these networks is then described in more detail. The technology used, its implementation in the wireless network infrastructure, and deployment experience are discussed.
Transition metal ion implantation into AlGaN (2003)

n- and p-type AlxGa1−xN (x=0.38 for n-type, x=0.13 for p-type) layers grown on Al2O3 substrates were ion implanted with the transition metals Mn, Cr, and Co at high concentrations (peak doping levels ∼3 at. %). After implantation and annealing at 1000 °C, only impurity transitions at ∼2.9 and 3.9 eV and no band-edge photoluminescence could be observed in all the samples. X-ray diffraction did not detect any peaks associated with second phase formation. Room-temperature hysteresis loops were obtained for Co-implanted n-type AlGaN, while there was no convincing evidence for ferromagnetism in the Mn- or Cr-implanted n-AlGaN. By sharp contrast, Mn implantation in p-AlGaN did produce ferromagnetic behavior and 300 K hysteresis. Both carrier type and crystalline quality can influence the resulting magnetic properties.
Ketamine and phencyclidine: the good, the bad and the unexpected (2015)

The history of ketamine and phencyclidine from their development as potential clinical anaesthetics through drugs of abuse and animal models of schizophrenia to potential rapidly acting antidepressants is reviewed. The discovery in 1983 of the NMDA receptor antagonist property of ketamine and phencyclidine was a key step to understanding their pharmacology, including their psychotomimetic effects in man. This review describes the historical context and the course of that discovery and its expansion into other hallucinatory drugs. The relevance of these findings to modern hypotheses of schizophrenia and the implications for drug discovery are reviewed. The findings of the rapidly acting antidepressant effects of ketamine in man are discussed in relation to other glutamatergic mechanisms.
Visualization by comprehensive microarray analysis of gene expression programs during transdifferentiation of mesophyll cells into xylem cells (2002)

Plants have a unique transdifferentiation mechanism by which differentiated cells can initiate a new program of differentiation. We used a comprehensive analysis of gene expression in an in vitro zinnia (Zinnia elegans L.) culture model system to gather fundamental information about the gene regulation underlying the transdifferentiation of plant cells. In this model, photosynthetic mesophyll cells isolated from zinnia leaves transdifferentiate into xylem cells in a morphogenic process characterized by features such as secondary-wall formation and programmed cell death. More than 8,000 zinnia cDNA clones were isolated from an equalized cDNA library prepared from cultured cells transdifferentiating into xylem cells. Microarray analysis using these cDNAs revealed several types of unique gene regulation patterns, including: the transient expression of a set of genes during cell isolation, presumably induced by wounding; a rapid reduction in the expression of photosynthetic genes and the rapid induction of protein synthesis-associated genes during the first stage; the preferential induction of auxin-related genes during the subsequent stage; and the transient induction of genes closely associated with particular morphogenetic events, including cell-wall formation and degradation and programmed cell death during the final stage. This analysis also revealed a number of previously uncharacterized genes encoding proteins that function in signal transduction, such as protein kinases and transcription factors that are expressed in a stage-specific manner. These findings provide new clues to the molecular mechanisms of both plant transdifferentiation and wood formation.
Transverse strain responses in the electrostrictive poly(vinylidene fluoride–trifluorethylene) copolymer (1999)

A large transverse electrostrictive strain S1 with a high elastic strain energy density is observed along the drawing direction in the stretched poly(vinylidene fluoride–trifluorethylene) copolymer film under a proper electron irradiation treatment condition, which results in a ratio of |S1/S3| larger than 1 where S3 is the longitudinal strain. In contrast, unstretched films generate a relatively small transverse strain with a small ratio of |S1/S3| (∼0.25). Hence, in this copolymer system, the ratio of |S1/S3| can be varied over a broad range. In addition, a large volume strain, which amounts to about half of the longitudinal strain, is observed in the films investigated.
Absence of TGF-β Receptors and Growth Inhibitory Responses in Retinoblastoma Cells (1988)

The responses of retinoblastoma tumor cells and normal retinal cells to various growth inhibitory factors were examined. Whereas fetal retinal cells were highly sensitive to the antimitogenic effects of transforming growth factor β1 (TGF-β1), retinoblastoma tumor cell lines were all resistant to this factor. Binding assays and affinity labeling of these cells with radioiodinated TGF-β1 revealed that the cells did not have TGF-β receptors. The retinoblastoma cells lacked the three affinity-labeled proteins of 65, 95, and 300 kilodaltons typically seen in human cell lines and thus differed from normal retinal cells and from other types of neuroectodermal tumors that display the normal pattern of receptors. Loss of TGF-β receptors, which is a rare event among tumor cells, may represent one mechanism through which these cells escape from negative control and form retinoblastomas.
Energy-based 6-DOF penetration depth computation for penalty-based haptic rendering algorithms (2007)

Existing penalty-based haptic rendering approaches compute penetration depth in strictly translational sense and cannot properly take object rotation into account. We aim to provide a theoretical foundation for computing the penetration depth on the group of rigid-body motions SE(3). We propose a penalty-based six-degrees-of-freedom (6-DOF) haptic rendering algorithm based on determining the closestpoint projection of the inadmissible configuration onto the set of admissible configurations. Energy is used to define the metric on the configuration space. Once the projection is found the 6-DOF wrench can be computed. The configuration space is locally represented with exponential coordinates to make the algorithm more efficient. Numerical examples compare the proposed algorithm with the existing approaches and show its advantages.
Effect of Chemical Treatment and Fiber Loading on Mechanical Properties ofBorassus(Toddy Palm) Fiber/Epoxy Composites (2015)

The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber–reinforced epoxy composites. Composites were prepared by the hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH) and alkali combined with silane (3-aminopropyltriethoxysilane) treatment of the fiber surface was carried out. Examinations through Fourier transform-infrared spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made with chemically modified and untreated Borassus fibers were studied using a universal testing machine. Based on the experimental results, it was found that the tensile properties of the Borassus-reinforced epoxy composites were significantly improved as compared with the neat epoxy. It was also found that the fiber treated with a combination of alkali and silane exhibited superior mechanical properties to alkali-treated and untreated fiber composites. The nature of the fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites.
Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures (2006)

This document describes a simple and efficient mechanism that can be
used to detect data plane failures in Multi-Protocol Label Switching
(MPLS) Label Switched Paths (LSPs). There are two parts to this
document: information carried in an MPLS request and echo
reply for the purposes of fault detection and isolation, and
mechanisms for reliably sending the echo reply. [STANDARDS-TRACK]
Extended donor criteria in lung transplantation (2009)

Although the available evidence for and against the commonly used lung donor selection criteria leaves many questions unanswered, it can help decrease the large number of uncertainties that be falls the practice of lung donor selection and recipient matching.
Video Retrieval Based on Language and Image Analysis (1999)

Abstract : This report summarizes the technical work ADVANCE Inc. performed under DARPA's contract no. MDA972-97-C-0014. This project has been conducted during an approximate two and one half year period in Phase I and Phase II implementation. The work performed has been focusing on the research and development of technologies for the indexing and retrieval of digital video content. The methodologies are built upon the theories of frame-based access and object-access, which allows users to index and retrieve video contents accordingly. Research is also performed on access at levels of video scene and video programs. For these purposes, algorithms for video shot boundary detection and keyframe extraction were developed. Closed captioning is extracted and associated with video shots so that keyword searching can be performed to retrieve video shots. Different approaches are used to segment video objects, including motion-based segmentation, and the combination of motion information and image cues for segmentation. Special objects such as human face and military target of interest were investigated as indexing points. Techniques for object identification and tracking were also studied for indexing and retrieving video contents. A comprehensive prototype has been built and software has been developed for frame-based access technologies.
MULTI-CENTRE EXPERIENCE WITH NON-INVASIVE EXPANDABLE GROWING PROSTHESIS (2005)

Introduction and Aims: Limb salvage surgery for the pediatric patient poses unique surgical challenges for the orthopaedic oncologist. In the past, surgeons have advocated amputation or rotationplasty as treatment for the skeletally immature child with a malignant bone tumor that involves a major growth plate and has an expected limb length discrepancy. Method: The Repiphysis is a non-invasively expandable prosthesis. Applications for the knee joint are approved and other joints are pending. The expansion principle involves energy stored in a spring compressed by a locking system. Lengthenings are achieved via exposure to an electromagnetic field that allows controlled release of the spring and can be done without general anesthesia. Numerous small expansions (5–10mm) keep pace as the child grows. Between 1998–2002, 25 prostheses [knee (19), shoulder (five), hip (one)] were implanted in 21 patients. Most were implanted at the time of tumor resection and nine were revisions from previous reconstruction or fusion. Results: Ninety lengthenings were performed with all but two on an outpatient basis. An average of 5mm was obtained per lengthening (range 1–35mm). The average follow-up was 25 months (range 12–48 months) and the latest Musculoskeletal Tumor Society functional scores averaged 87%. Eight revisions were required for mechanical problems or stem loosening. There was one amputation caused by post-operative arterial thrombosis. Conclusion: This unique prosthesis offers many benefits in maintaining limb-length equality in growing patients. We are optimistic that this technology will prove beneficial to patients with malignant bone tumors as well as patients requiring serial limb lengthening or those with spinal deformities.
Sensitive and specific DNA probe for detection of Plasmodium falciparum. (1986)

The isolation and some characteristics of a very sensitive DNA probe for the detection of Plasmodium falciparum are described. The probe is species specific and represents a large, albeit variable, fraction of the genome in all the strains tested. In addition to its immediate practical uses for the detection and quantitation of parasites, the probe defines an interesting family of repeated sequences.
Multiarm spirals in a two-dimensional cardiac substrate (2004)

A variety of chemical and biological nonlinear excitable media, including heart tissue, can support stable, self-organized waves of activity in a form of rotating single-arm spirals. In particular, heart tissue can support stationary and meandering spirals of electrical excitation, which have been shown to underlie different forms of cardiac arrhythmias. In contrast to single-arm spirals, stable multiarm spirals (multiple spiral waves that rotate in the same direction around a common organizing center) have not been demonstrated and studied yet in living excitable tissues. Here, we show that persistent multiarm spirals of electrical activity can be induced in monolayer cultures of neonatal rat heart cells by a short, rapid train of electrical point stimuli applied during single-arm-spiral activity. Stable formation is accomplished only in monolayers that show a relatively broad and steep dependence of impulse wavelength and propagation velocity on rate of excitation. The resulting multiarm spirals emit waves of electrical activity at rates faster than for single-arm spirals and exhibit two distinct behaviors, namely "arm-switching" and "tip-switching." The phenomenon of rate acceleration due to an increase in the number of spiral arms possibly may underlie the acceleration of functional reentrant tachycardias paced by a clinician or an antitachycardia device.
Experimental Herpes Simplex Infection in the Owl Monkey. (1967)

SummaryThe owl monkey, Aotus trivir-gatus, was found to be extremely susceptible to infection with a strain of Herpesvirus hominis. The infection was established by ocular inoculation without corneal scarification, rapidly involved the upper respiratory tract, blood, and became widespread, systemically. Generally animals died within a period of 6 days after inoculation and virus was recovered from all organs and the CNS. Exposure of well to sick animals resulted in similar generalized disease and death in a majority of those exposed. The pathology of generalized infection closely resembled H. hominis infection of the human new born infant.
Design of dispersion-compensating Bragg fiber with an ultrahigh figure of merit (2005)

We report a novel idea for achieving highly efficient dispersion-compensating Bragg fiber by exploiting a modified quarter-wave stack condition. Our Bragg fiber yielded an average dispersion of approximately -1800 ps/(nm km) across the C band for the fundamental TE mode and an ultrahigh figure of merit of approximately 180,000 ps/(nm dB), which is at least 2 orders of magnitude higher than that of conventional dispersion-compensating fibers. The proposed methodology could be adopted for the design of a dispersion compensator across any desired wavelength range.
Regulation of storage protein gene expression inArabidopsis (2003)

The expression of seed storage proteins is under tight developmental regulation and represents a powerful model system to study the regulation of gene expression during plant development. In this study, we show that three homologous B3 type transcription factors regulate the model storage protein gene, At2S3, via two distinct mechanisms: FUSCA3 (FUS3) and LEAFY COTYLEDON2 (LEC2) activate the At2S3 promoter in yeast suggesting that they regulate At2S3 by directly binding its promoter; ABSCISIC ACID INSENSITIVE3 (ABI3), however, appears to act more indirectly on At2S3, possibly as a cofactor in an activation complex. In accordance with this, FUS3 and LEC2 were found to act in a partially redundant manner and differently from ABI3 in planta: At2S3expression is reduced to variable and sometimes only moderate extent in fus3 and lec2 single mutants but is completely abolished in the lec2 fus3 double mutant. In addition, we found that FUS3and LEC2 expression patterns, together with an unsuspected regulation of FUS3 by LEC2, enable us to explain the intriguing expression pattern of At2S3 in lec2 or fus3 single mutants. Based on these results, we present a model of At2S3regulation and discuss its implications for other aspects of seed maturation.