gebhart/patrepeval huggingface dataset:
Total synthesis of calicheamicin .gamma.1I. 2. Development of an enantioselective route to (-)-calicheamicinone (1993)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTotal synthesis of calicheamicin .gamma.1I. 2. Development of an enantioselective route to (-)-calicheamicinoneA. L. Smith, E. N. Pitsinos, C. K. Hwang, Y. Mizuno, H. Saimoto, G. R. Scarlato, T. Suzuki, and K. C. NicolaouCite this: J. Am. Chem. Soc. 1993, 115, 17, 7612–7624Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://pubs.acs.org/doi/10.1021/ja00070a005https://doi.org/10.1021/ja00070a005research-articleACS PublicationsRequest reuse permissionsArticle Views2293Altmetric-Citations102LEARN 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
Three-dimensional photoacoustic imaging using fiber-based line detectors (2010)

For photoacoustic imaging, usually point-like detectors are used. As a special sensing technology for photoacoustic imaging, integrating detectors have been investigated that integrate the acoustic pressure over an area or line that is larger than the imaged object. Different kinds of optical fiber-based detectors are compared regarding their sensitivity and resolution in three-dimensional photoacoustic tomography. In the same type of interferometer, polymer optical fibers yielded much higher sensitivity than glass fibers. Fabry-Perot glass-fiber interferometers in turn gave higher sensitivity than Mach-Zehnder-type interferometers. Regarding imaging resolution, the single-mode glass fiber showed the best performance. Last, three-dimensional images of phantoms and insects using a glass-fiber-based Fabry-Perot interferometer as integrating line detector are presented.
Quadrupolar Echoes in Solids (1969)

In a classic paper, Solomon showed that the presence of inhomogeneous, first-order quadrupolar interactions leads to the formation of extra "allowed" spin echoes in nuclei for which the spin $I=\frac{5}{2}$. We demonstrate (both theoretically and experimentally) that shifting the rf phase of the second pulse by 90\ifmmode^\circ\else\textdegree\fi{} (in a spin-$\frac{5}{2}$ system) enhances the extra allowed echoes by a factor of almost 5 in amplitude over the unshifted case. Using the density-matrix formulation (and assuming no magnetic inhomogeneities), we have derived, for a 90\ifmmode^\circ\else\textdegree\fi{} phase shift, the amplitude and shape dependence on the second-pulse turning angle of the $\frac{3}{2}\ensuremath{\tau}$, $2\ensuremath{\tau}$, and $3\ensuremath{\tau}$ echoes. Experimental echo amplitudes and shapes (for both 0\ifmmode^\circ\else\textdegree\fi{} and 90\ifmmode^\circ\else\textdegree\fi{} phase shifts) were obtained, at room temperature, on $^{127}\mathrm{I}$ in a fused sample of KI, and these show good agreement with the calculations. Because of the enhancement, this technique affords a much easier separation of the respective distributions arising from the $\frac{3}{2}\ensuremath{\leftrightarrow}\frac{5}{2}$ and from the $\frac{1}{2}\ensuremath{\leftrightarrow}\frac{3}{2}$ satellite transitions than is possible in the unshifted case. Another feature of the phase-shifted case is that, in favorable circumstances, the $3\ensuremath{\tau}$ echo may be observed although the $2\ensuremath{\tau}$ echo is obscured by the receiver recovery time. Preliminary data on quadrupole distributions at Al sites in NiAl and Au${\mathrm{Al}}_{2}$ intermetallic compounds are presented. Spin-spin relaxation of the satellite transitions is noted. Results expected for systems which have spin values other than $I=\frac{5}{2}$ (both integral and half-integral) are mentioned.
Synthesis of NaX Zeolites with Metallophthalocyanines (1992)

Aluminosilicate molecular sieves with the FAU structure have been crystallized in the presence of several metallophthalocyanines. A percentage of the complexes becomes included into the zeolites. The synthesis of NaX around the metal chelate represents a new method for encapsulating such complexes and modifying zeolite molecular sieves. The entrapped complexes were characterized by XRD, IR and UV-VIS spectroscopy. Preliminary results suggest the metal complexes may function as templates by modifying the gel chemistry.
Investigations of Charge Migration and Charge Trapping in Fatigued Organic Photoconductors (2012)

This article presents the experimental photodischarge kinetics of electrostatically fatigued dual-layer organic photoconductors characterized by an electrophotographic incremental charging technique that reveals the differences in the photoconductor charging profiles. During normal operation, 15% of the holes that migrate to the surface after photodischarge are not neutralized by the negative surface ions. The accumulation of these lingering surface charges (charge transport material radical cations) manifests itself as defects in half-tone images, as either missing or reduced size dots or lines. In the presence of corona gases, these surface holes oxidize and reduce the energy barrier for hole injection from a positively charged surface, e.g., contact with a transfer roller. These injected holes accumulate near the charge generation layer and require twice the amount of negative charge to attain the same surface potential as that of a new organic photoconductor (OPC) drum. The damaged depth of this injection region extends to about 50 nm into the OPC surface and is easily removed by the printer’s abrasion mechanisms (e.g., cleaning blade, toner, paper).
Low bend loss waveguides and photonic bandgaps enabled by high index contrast modifications (2013)

We present a novel process to fabricate high index contrast waveguides in boro-aluminosilicate glass based on differential thermal post-annealing. Firstly, large high index contrast multimode waveguides are inscribed and subsequently annealed to achieve single-mode operation. We applied this technique to significantly increase the throughput of 3D astrophotonic devices and to demonstrate anti-resonant (ARROW) guiding in a laser written structure for the first time.
Molecular population genetic analysis of the streptokinase gene of <i>Streptococcus pyogenes</i>: mosaic alleles generated by recombination (1995)

To understand the mechanisms governing molecular evolution of the streptokinase gene (skn), a 384 bp DNA fragment encoding two variable regions of the molecule was characterized in 47 isolates of Streptococcus pyogenes. The results reveal that alleles of the streptokinase gene have a mosaic structure, and provide strong evidence for intragenic recombination. Moreover, organisms that are well differentiated in overall chromosomal character have identical skn alleles, which suggests that horizontal gene transfer and recombination have participated in the evolution of this locus. No simple relationship between skn allele and serum opacity factor production or specific disease was identified. The predicted amino acid sequences of highly divergent skn alleles are strikingly similar in hydrophilicity and hydrophobicity profiles, distribution of amphipathic and flexible regions, surface probability plots, and antigenic indices, indicating that despite extensive nucleotide polymorphism in the two skn variable regions, selective pressure has constrained overall structural divergence. These results add to an important emerging theme that intragenic recombination plays a critical role in diversifying genes coding for streptococcal virulence factors.
Cloning, sequencing and characterization of the biosynthetic genecluster of sanglifehrin A, a potent cyclophilininhibitor (2010)

Sanglifehrin A (SFA), a potent cyclophilin inhibitor produced by Streptomyces flaveolus DSM 9954, bears a unique [5.5] spirolactam moiety conjugated with a 22-membered, highly functionalized macrolide through a linear carbon chain. SFA displays a diverse range of biological activities and offers significant therapeutic potential. However, the structural complexity of SFA poses a tremendous challenge for new analogue development via chemical synthesis. Based on a rational prediction of its biosynthetic origin, herein we report the cloning, sequencing and characterization of the gene cluster responsible for SFA biosynthesis. Analysis of the 92 776 bp contiguous DNA region reveals a mixed polyketide synthase (PKS)/non-ribosomal peptide synthetase (NRPS) pathway which includes a variety of unique features for unusual PKS and NRPS building block formation. Our findings suggest that SFA biosynthesis requires a crotonyl-CoA reductase/carboxylase (CCR) for generation of the putative unusual PKS starter unit (2R)-2-ethylmalonamyl-CoA, an iterative type I PKS for the putative atypical extender unit (2S)-2-(2-oxo-butyl)malonyl-CoA and a phenylalanine hydroxylase for the NRPS extender unit (2S)-m-tyrosine. A spontaneous ketalization of significant note, may trigger spirolactam formation in a stereo-selective manner. This study provides a framework for the application of combinatorial biosynthesis methods in order to expand the structural diversity of SFA.
Antibodies to N-acetylglucosamine and heparin in acute and remission phases of rheumatic fever. (1991)

The etiology of acute rheumatic fever (ARF) is believed to involve an immunological response to group A streptococcal antigens. Antibodies to group A carbohydrate (A-CHO) have been reported in ARF and rheumatic heart disease patients. As N-acetylglucosamine (GlcNAc) units form the major immunodominant regions in A-CHO antigens, we investigated levels of antibodies to GlcNAc and heparin (with repeated sequences of GlcNAC) in rheumatic fever (RF) patients. Serum samples from 26 acute cases (ARF), 18 remission cases and 17 normal healthy subjects were analyzed for IgG and IgM levels of antibodies to GlcNAc and heparin. High titres of IgG antibodies to heparin and GlcNAc were observed in the ARF group in comparison with controls (p less than 0.0025 and 0.0125 respectively). There was no difference in the levels of IgM antibodies. Remission group demonstrated low titres of IgG to heparin and GlcNAc (p less than 0.01 and 0.0125 respectively) in comparison with ARF group. Heparin antibodies of IgM class was comparatively lower in remission group (p less than 0.005). While the role of these antibodies in different phases of RF needs to be investigated, we conclude that GlcNAc antibodies do not play any role in the pathogenesis of RF or rheumatic heart disease.
Altered macroautophagy in the spinal cord of SOD1 mutant mice (2008)

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by selective loss of motor neurons (MNs). About 20% familial cases of ALS (fALS) carried the Cu, Zn-superoxide dismutase (SOD1) gene mutation, which plays a crucial role in the pathogenesis of fALS. There is evidence suggesting that macroautophagy can degrade mutated SOD1 in vitro. To investigate whether the mutant SOD1 can induce macroautophagy in vivo, we examined the LC3 processing in spinal cord and the activation status of macroautophagy in MNs of SOD1(G93A) transgenic mice at different stages. Our data demonstrated that autophagy was activated in spinal cord of SOD1(G93A) mice indicating a possible role of macroautophagy in the pathogenesis of ALS.
p53 and apoptosis alterations in keloids and keloid fibroblasts (1998)

Keloids are the result of a dysregulated wound-healing process and are characterized by formation of excess scar tissue that proliferates beyond the boundaries of the inciting wound. In this study, we investigated the expression of key proteins involved in regulating apoptosis in keloids. Twenty archival paraffin-embedded keloid samples were randomly selected for an immunoperoxidase assay with antibodies against fas, p53, bcl-2, and bcl-x proteins using the target antigen-retrieval technique. Apoptosis was assessed in keloids and normal skin and in keloid and normal fibroblasts by the TdT-mediated dUTP nick-end labeling (tunel) assay on tissue sections, fibroblast cultures, and by flow cytometry for cell suspensions. We found that 18 of 20 keloids expressed p53 protein; bcl-2 was expressed by keloid fibroblasts in 19 of 20 keloids, and all specimens had prominent fas expression throughout the tissue. The distribution of these three antigens was regional within each lesion and followed a consistent pattern of p53 and bcl-2 expression colocalized to the hypercellular, peripheral areas of each keloid in a perinuclear pattern (p < .001). In contrast, an inverse distribution of fas expression was shown, with staining being more diffuse across the cell surfaces and limited to the central, more hypocellular regions in16 of 17 keloids (p < .001). There was no specific staining pattern in these keloids with antihuman bcl-x. In vitro studies on cultured keloid fibroblasts (derived from six patients) revealed maintenance of the p53+, bcl-2+ phenotype up to passage 10. Neither neonatal nor normal adult skin fibroblasts expressed either antigen but could be induced to express p53 by exposure to adriamycin. Keloid lesions and keloid fibroblasts were found to have lower rates of apoptosis than normal controls. Keloid fibroblasts displayed enhanced apoptosis rates in response to hydrocortisone, gamma interferon, and hypoxia treatment as compared with normal adult fibroblasts. Focal dysregulation of p53 combined with upregulation of bcl-2 may help produce a combination of increased cell proliferation and decreased cell death in the younger, hypercellular areas of the keloid. This phenotype is reversed in the older areas of the keloid and may prevent malignant degeneration, thus favoring normal apoptosis as evidenced by prominent fas expression.
<title>Device Parameters And Optical Performance Of A Stacked Actuator Deformable Mirror</title> (1980)

A discrete-actuator, deformable mirror has been characterized for use in the infrared spectral region. This device, with a clear aperture diameter of nine inches, achieves a surface deformation of 8.5 μm at 1500 volts. Conformity of the reflective surface with a desired figure has been determined by interferometric analysis and residual error computation for focus, tip, tilt and two orders of astigmatism.
General Error Analysis in the Relationship between Free Thyroxine and Thyrotropin and Its Clinical Relevance (2013)

When the main uncertainties in thyroid function tests (TFT) are identified and analyzed, we can find the most acceptable model space with which we can construct the best HP function and the related set point area.
GRAPHICAL ARRANGEMENTS OF COMPRESSED GRAPHS (2014)

We show that if a graph G is compressed, then the proper part of the intersection poset of the corresponding graphical arrangement <TEX>$A_G$</TEX> has the homotopy type of a wedge of spheres. Furthermore, we also indicate the number of spheres in the wedge, based on the number of adjacent edges of vertices in G.
CONTRIBUTION TO THE PATHOGENESIS OF HEMOPHILIA (1947)

Abstract The causes of the delayed coagulation of hemophilic blood seem to become clearer as time advances. On one side we have the investigations of the school of Minot, indicating a deficit in the globulin fraction; and on the other side are the works of those who maintain that there exists an excess of anticoagulant substances. We support the latter theory, although in our opinion the two theories do not contradict each other, since it might be possible that this anticoagulant substance would act on the globulin fraction diminishing its coagulant power. This substance could be identified with the anticephalin fraction of Tocantins. With the idea that this substance might be less stable than the coagulant fractions (fibrinogen, prothrombin, and thromboplastin) we have tried to render it inactive by keeping the blood in a refrigerator for a certain length of time. Inactivity was obtained in some of our experiments. We know that the stability of this substance varies from one patient to the other, but we have not been able to fix the cause of these variations. In conclusion, we consider that other means of neutralizing the action of this anticoagulant substance should be investigated. This inactivity once obtained, we should have advanced far in solving the intricate problem of hemophilia.
A generalized structural subband decomposition of FIR filters and its application in efficient FIR filter design and implementation (1993)

It is shown that any FIR (finite-impulse-response) transfer function can be realized as a parallel connection of interpolated FIR (IFIR) sections consisting of a cascade of a subfilter with a sparse impulse response and an FIR interpolator which fills in the missing samples of the corresponding subfilter. The set of interpolators can be realized as a subband filter bank, and as a result, each IFIR section contributes to the overall frequency response essentially within a given band of frequencies. The proposed decomposition can be considered as a generalization of the polyphase decomposition. It results in a computationally efficient structure in sampling rate alteration applications and also leads to faster FIR filter design algorithms. Examples are included to demonstrate the improvements in the speed of least-squares and minimax design algorithms based on the suggested structure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Soft computing based car body deformation and EES determination for car crash analysis systems (2004)

Car body deformation modeling plays a very important role in crash accident analyses, as well as in safe car body design. The determination of the energy absorbed by the deformation and the corresponding energy equivalent speed can be of key importance, however their precise determination is a very difficult task. Although, using the results of crash tests, intelligent and soft methods offer a way to model the crash process itself, as well as to determine the absorbed energy, the before-crash speed of the car, etc. In this paper a modeling technique and an intelligent expert system are introduced which together are able to follow the deformation process of car bodies in car crashes and to analyze the strength of the different parts, thus significantly can contribute to the improvement of the safety of car bodies.
Hybrid transformer ZVS/ZCS DC-DC converter for photovoltaic microinverters (2013)

This paper presents a high boost ratio dc-dc converter with hybrid transformer for non-isolated photovoltaic (PV) microinverters. The proposed converter incorporates the resonant operation mode into the traditional high boost ratio active-clamp coupled-inductor PWM converter, achieving ZVS turn-on of the switches and ZCS turn-off of the diodes. As a result of the inductive and capacitive energy being transferred simultaneously within both turn-on and turn-off intervals of the main switch, the dc bias of the magnetizing current is reduced and hence the size of magnetics can be reduced. The magnetizing inductance is designed with a small value to utilize ripple magnetizing current to assist ZVS of main switch, while maintaining low RMS conduction losses. The voltage stresses on the active switches and diodes are maintained at a low level and are independent of the wide changing input PV voltages as a result of the resonant capacitor in series in the energy transfer loop. The experimental results based on 250 W prototype circuit show system CEC efficiencies greater than 96.7% over 20 V to 45 V PV voltage range.
De ertsvoorkomens van Spanje (1992)

Vanaf het eerste begin van menselijke mijnbouwactiviteiten stond het Iberisch Schiereiland in de belangstelling; waarschijnlijk waren reeds in het zesde millennium v.Chr. in Iberia ertsafzettingen bekend. Phoeniciers, Grieken, Carthagers en Romeinen wonnen en bewerkten goud, zilver, koper, lood en kwik (Las Medulas, Tharsis, Cartagena, Almaden, enz.). Tinerts, van groot belang voor de fabricage van brons, werd in de latere eeuwen van de Bronstijd uit Bre-tagne, Cornwall en Galicie gehaald, de 'Cassiteriet-Eilanden buiten Europa', zoals deze gebieden werden genoemd door Herodotus. Na de val van het Romeinse Rijk stopten alle mijnbouwactiviteiten volledig, zij werden eerst weer door de Arabieren opgenomen. De mijnbouw kwam echter weer vrijwel volledig tot stilstand door de ontdekking van de mineralenrijkdommen van Amerika. Op enkele plaatsen werd de activiteit in de 18de eeuw weer opgenomen (Almaden en Rio Tinto), maar het duurde tot het midden van de 19de eeuw voor er in Spanje weer sprake was van een begin van iets uitgebreidere mijnbouwactiviteiten. Deze werden echter voornamelijk door Fransen en Engelsen gefinancierd en geleid. Vrijwel de gehele produktie aan metalen als koper en ijzer verdween dan ook naar de andere Europese landen, een situatie die tot vlak voor de Tweede Wereldoorlog heeft voortgeduurd. Daarna heeft de vraag van de zich snel ontwikkelende Spaanse industrie het aanbod van vele mineralen van eigen bodem snel overtroffen. De belangrijkste mijnbouwgebieden van Spanje zijn: Asturie met steenkool en fluoriet; Castilie, Leon en Palencia (steenkool); Salamanca voor uranium, tin en wolfram; Burgos voor glauberiet. Andalusie is vooral van belang door het voorkomen van de grote pyrietgordel van de provincie Huelva, waar een groot aantal sulfi-dische ertsen wordt gewonnen, o.a. koper, ijzer, lood en zink; in de provincie Granada komt ijzererts voor, Sevilla en Jaen leveren sulfidische metaalertsen en Cordoba steenkool. Afb. 1. Een aantal belangrijke voorkomens van een aantal ertsen en mineralen zullen we hier de revue laten passeren.
Bis[di(hydroxymethyl)phosphinato]diaquacobalt(II), [Co(H2O)2{(HOCH2)2PO2}2]: Synthesis, properties, and crystal structure (2006)

The synthesis and some properties of the Co(II) complex with di(hydroxymethyl)phosphinic acid (HL) of the composition CoL2·2H2O are described. X-ray powder diffraction analysis confirmed the phase homogeneity of the polycrystalline sample. The crystal structure is determined by X-ray diffraction method. The Co atom is located in the center of octahedron formed by the O atoms of two ligands L and of two water molecules. The ligand L performs bidentate-chelate function and is bonded to the Co atom through the O atoms of the phosphinate group and of one alcohol group.
40.2: Sequential Color Recapture and Dynamic Filtering: A Method of Scrolling Color (2001)

Abstract Scrolling color has long been a goal of the projector industry, as it enables the most efficient use of light in a single panel display. Current methods of implementing scrolling color use the techniques of splitting the light into primary colors, and manipulating that light on the modulator. The authors present the techniques of dynamic filtering and sequential color recapture (SCR) to achieve the same result with no moving components other than a color wheel, showing that the efficiency of 3‐modulator systems can be approached with one modulator. Analysis of the technique applied to DLP™ projection displays, and results of prototype projection systems using the techniques, will be presented.