gebhart/patrepeval huggingface dataset:
The occurrence and possible functional significance of ‐S‐S‐ crosslinks in sperm heads, with particular reference to eutherian mammals (1974)

Abstract The extraordinary resistance to disruption shown by the eutherian sperm nucleus is associated with a significant complement of ‐S‐S‐ crosslinks within the chromatin. The present light and electron microscopic study, in which the spermatozoa of many vertebrates and some invertebrates were exposed to SDS with or without dithiothreitol, demonstrates that the extreme degree of disulfide bonding in the sperm chromatin of eutherian mammals is highly unusual in a comparative sense. In no other species did the sperm nucleus display a resistance to disruption comparable to that in eutherians; on the contrary, in most groups including prototherian and metatherian mammals, such crosslinks are absent or relatively sparse, the greatest degree of crosslinking outside the eutheria being seen in octopus and skate. The suggestion is advanced that the unusually thiol‐rich protamines have evolved as a structural adaptation which, through crosslinking, endows the sperm head with a rigidity of possible importance in the penetration phase of fertilization. This seems likely because (1) any degree of ‐S‐S‐ determined stability present or inducible in sperm chromatin often appears more intense in or is confined to the anterior region of the nucleus (e.g., newt, snail, turtle and immature eutherian spermatozoa); (2) the zona pellucida, which the fertilizing sperm must penetrate, is an unusually thick, compact and resilient coat in the eutherian ovum in particular; and (3) the occasional observation of a sperm nucleus buckled within the pathway of its penetration into the rabbit zona pellucida suggests that in eutheria this tough vestment presents a relatively rigid barrier to the sperm head. Its apical location suggests a similar structural role for the ‐S‐S‐ stabilised perinuclear projection, or “perforatorium” around the leading border of the sperm nucleus in eutherians as well as in some non‐eutherian species, such as octopus, snake and turtle.
Cooperative stimulated Brillouin and Rayleigh backscattering process in optical fiber (1998)

We observed an unusually narrow spectrum of Stokes field and Gaussian statistics of Stokes power for the stimulated Brillouin scattering (SBS) process in 300-m single-mode optical fiber with high Rayleigh losses. The measured characteristics of the Stokes radiation indicate that SBS lasing took place in the fiber. The effect is explained as the result of dynamic distributed feedback that is due to double Rayleigh scattering (RS) of the Stokes field. The results of numerical simulation of the cooperative SBS-RS process in fiber are in good agreement with experimental results.
mtDNA depletion with variable tissue expression: a novel genetic abnormality in mitochondrial diseases. (1991)

We studied two related infants with a fatal mitochondrial disease, affecting muscle in one and liver in the other. Quantitative analysis revealed a severe depletion of mtDNA in affected tissues. This genetic abnormality was also observed in muscle of an unrelated infant with myopathy and in muscle and kidney of a fourth child with myopathy and nephropathy. Biochemistry, immunohistochemistry, and in situ hybridization showed that the depletion of mtDNA in muscle fibers was correlated with a respiratory chain defect and with lack of mitochondrially translated proteins. Although the differential tissue involvement in these infants suggests mtDNA heteroplasmy, sequence analysis of mtDNA replication origins did not reveal any abnormality that could account for the low copy number.
Image analysis of Doppler echocardiography for patients with atrial fibrillation (2005)

Image analysis tools are used for the extraction of clinical data from Doppler echocardiography images. Currently, manual methods are subject to large inter- and intraobserver variability. The proposed automated methodology may provide a more robust method and a powerful tool for noninvasive evaluation of cardiac haemodynamics, especially for patients with atrial fibrillation (ATF) patients suffer from a nonhomogenous heart rate, and the shape of the Doppler signal obtained from them differs from beat to beat. This variability requires the averaging of several measures in order to produce acceptable clinical data. The presented methodology works on signals from the mitral valve (MV) and the tricuspid valve (TV), and detects the envelope of the velocity vs. time function, the maximal velocity envelope (MVE). From the MVE, clinical data is extracted, such as the peak velocity and the area beneath the curve. Parameters taken from several beats in a single image are averaged in order to provide more representative and robust results. Experimental results show a strong correlation between the automatically extracted parameters and parameters acquired manually by an echo technician.
A comparison of radiation shielding of stainless steel with different magnetic properties (2014)

The radiation shielding properties of three different stainless steels have been investigated. For this purpose, linear attenuation coefficients at photon energy levels of 662 keV and 1250 keV have been measured. The obtained results showed that ferritic stainless steel was more capable in stopping the high energy photons than its non-magnetic counterpart.
Structural and Conducting Studies on Manganese-, Cobalt-, Nickel-, Copper-, Zinc- and Cadmium(II) Polychelates (1997)

Department of Chemistry, Amravati University, Amravati-444 602 <em>Manuscript received 4 December 1995, revised 15 July 1996, accepted 3 September 1996</em> Chelates of Mn<sup>II</sup>, Co<sup>II</sup>, Ni<sup>ll</sup>, Cu<sup>ll</sup>, Zn<sup>ll</sup> and Cd<sup>ll</sup> have been prepared from bis(mercaptoacetamide)-<em>p</em>-phenylenediamine [BMAPD]. All the chelates are coloured amporphous solids and highly insoluble in water and common organic solvents. Thermogravimetric analysis has been carried out. Kinetic and thermodynamic parameters have also been evaluated by using thermal decomposition pattern. D.C. electrical conductivity study has also been carried out.
Machine translation based data augmentation for Cantonese keyword spotting (2016)

This paper presents a method to improve a language model for a limited-resourced language using statistical machine translation from a related language to generate data for the target language. In this work, the machine translation model is trained on a corpus of parallel Mandarin-Cantonese subtitles and used to translate a large set of Mandarin conversational telephone transcripts to Cantonese, which has limited resources. The translated transcripts are used to train a more robust language model for speech recognition and for keyword search in Cantonese conversational telephone speech. This method enables the keyword search system to detect 1.5 times more out-of-vocabulary words, and achieve 1.7% absolute improvement on actual term-weighted value.
Sequential bilateral transplantation in Parkinson's disease: Effects of the second graft (1999)

Five parkinsonian patients who had received implants of human embryonic mesencephalic tissue unilaterally in the striatum 10-56 months earlier were grafted with tissue from four to eight donors into the putamen (four patients) or the putamen plus the caudate nucleus (one patient) on the other side, and were followed for 18-24 months. After 12-18 months, PET showed a mean 85% increase in 6-L-[18F]fluorodopa uptake in the putamen with the second graft, whereas there was no significant further change in the previously transplanted putamen. Two patients exhibited marked additional improvements after their second graft: 'on-off' fluctuations virtually disappeared, movement speed increased, and L-dopa could be withdrawn in one patient and reduced by 70% in the other. The improvement in one patient was moderate. Two patients with atypical features, who responded poorly to the first graft, worsened following the second transplantation. These findings indicate that sequential transplantation in patients does not compromise the survival and function of either the first or the second graft. Moreover, putamen grafts that restore fluorodopa uptake to normal levels can give improvements of major therapeutic value.
Semiconducting Carbon Nanotubes (2005)

The use of Raman spectroscopy to reveal the remarkable structure and properties of carbon nanotubes is briefly reviewed. Particular emphasis is given to the fact that a nanotube can be semiconducting or metallic depending on its diameter dt and chirality θ, and how Raman spectroscopy at the single nanotube level reveals such information. Some of the implications of the unusual properties of carbon nanotubes are summarized. It is shown how the vibrational spectra of one tiny tube, only about 1 nm in diameter, can be observed experimentally. Raman spectroscopy normally measures vibrational frequencies. What is unique about carbon nanotubes is that for this one‐dimensional system, resonance Raman spectroscopy (RRS) also determines, in addition, the geometrical structure of the resonant nanotube, that is its diameter and chirality. Some of the recent advances in single nanotube spectroscopy are briefly discussed. The use of RRS for characterizing carbon nanotube samples is also discussed. The connection between Raman spectroscopy and photoluminescence for studying carbon nanotubes is mentioned. Some of the current research challenges facing the field are briefly summarized.
Bulk assembly of organic metal halide nanotubes (2017)

The organic metal halide hybrids welcome a new member with a one-dimensional (1D) tubular structure. Herein we report the synthesis and characterization of a single crystalline bulk assembly of organic metal halide nanotubes, (C<sub>6</sub>H<sub>13</sub>N<sub>4</sub>)<sub>3</sub>Pb<sub>2</sub>Br<sub>7</sub>. In a metal halide nanotube, six face-sharing metal halide dimers (Pb<sub>2</sub>Br<sub>9</sub><sup>5-</sup>) connect at the corners to form rings that extend in one dimension, of which the inside and outside surfaces are coated with protonated hexamethylenetetramine (HMTA) cations (C<sub>6</sub>H<sub>13</sub>N<sub>4</sub><sup>+</sup>). This unique 1D tubular structure possesses highly localized electronic states with strong quantum confinement, resulting in the formation of self-trapped excitons that give strongly Stokes shifted broadband yellowish-white emission with a photoluminescence quantum efficiency (PLQE) of ∼7%. Having realized single crystalline bulk assemblies of two-dimensional (2D) wells, 1D wires, and now 1D tubes using organic metal halide hybrids, our work significantly advances the research on bulk assemblies of quantum-confined materials.
Synthesis, Structural Characterization, Gas Sorption and Guest-Exchange Studies of the Lightweight, Porous Metal−Organic Framework α-[Mg<sub>3</sub>(O<sub>2</sub>CH)<sub>6</sub>] (2006)

Unsolvated magnesium formate crystallizes upon reaction of the metal nitrate with formic acid in DMF at elevated temperatures. Single-crystal XRD studies reveal the formation of [Mg3(O2CH)6 [symbol: see text] DMF], 1, a metal-organic framework with DMF molecules filling the channels of an extended diamondoid lattice. The DMF molecules in 1 can be entirely removed without disruption to the framework, giving the guest-free material alpha-[Mg3(O2CH)6], 2. Compound 2 has been characterized by both powder and single-crystal XRD studies. Thermogravimetric analyses of 1 show guest loss from 120 to 190 degrees C, with decomposition of the sample at approximately 417 degrees C. Gas sorption studies using both N2 and H2 indicate that the framework displays permanent porosity. The porosity of the framework is further demonstrated by the ability of 2 to uptake a variety of small molecules upon soaking. Single-crystal XRD studies have been completed on the six inclusion compounds [Mg3(O2CH)6 [symbol: see text] THF], 3; [Mg3(O2CH)6 [symbol: see text] Et2O], 4; [Mg3(O2CH)6 [symbol: see text] Me2CO], 5; [Mg3(O2CH)6 [symbol: see text] C6H6], 6; [Mg3(O2CH)6 [symbol: see text] EtOH], 7; and [Mg3(O2CH)(6) [symbol: see text] MeOH], 8. Analyses of the metrical parameters of 1-8 indicate that the framework has the ability to contract or expand depending on the nature of the guest present.
Regulation der Biosynthese der aromatischen Aminosäuren in <i>Saccharomyces cerevisiae</i> (1967)

We have studied the repression of the first enzymes of the main branch and the pathways after the branchpoint in the aromatic biosynthesis of Saccharomyces cerevisiae . Anthranilate synthetase is repressed by l ‐tryptophan and prephenate dehydratase by l ‐phenylalanine. 3‐Deoxy‐ d ‐arabinoheptulosonic acid 7‐phosphate (DAHP) synthetases are not repressed by l ‐phenylalanine, l ‐tyrosine and l ‐tryptophan, chorismate mutases are repressed neither by l ‐phenylalanine nor by l ‐tyrosine, and prephenate dehydrogenase shows no repression by l ‐tyrosine. l ‐Tryptophan exhibits an induction of the chorismate mutase. Besides chorismate mutase is activated by l ‐tryptophan. l ‐Phenylalanine exhibits an induction and also an activation of the prephenate dehydrogenase. By simultaneous addition of l ‐tryptophan, l ‐phenylalanine, and l ‐tyrosine p ‐aminobenzoic acid was accumulated and the production of p ‐aminobenzoate synthetase was induced. The tyrosine‐sensitive and phenylalanine‐sensitive isoenzymes of DAHP synthetase belong to the V‐system of the allosteric enzymes. Chorismate mutase and prephenate dehydrogenase are members of the K‐system. In an earlier publication we have discussed the feedback inhibition of the described enzymes. In this paper we discuss the whole events of the regulation phenomena in Saccharomyces cere‐visiae . We also considered the degradation of l ‐tryptophan, l ‐phenylalanine, and l ‐tyrosine to tryptophol, phenylethanol, and tyrosol respectively in connection with the regulatory events.
THE STRUCTURE OF THE CONDENSATION PRODUCTS OF ORTHO-PHTHALALDEHYDIC ACIDS WITH PHENOLS AND PHENOL ETHERS. VIII.<sup>1</sup> (1927)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE STRUCTURE OF THE CONDENSATION PRODUCTS OF ORTHO-PHTHALALDEHYDIC ACIDS WITH PHENOLS AND PHENOL ETHERS. VIII.1M. M. Brubaker and Roger AdamsCite this: J. Am. Chem. Soc. 1927, 49, 9, 2279–2296Publication Date (Print):September 1, 1927Publication History Published online1 May 2002Published inissue 1 September 1927https://pubs.acs.org/doi/10.1021/ja01408a022https://doi.org/10.1021/ja01408a022research-articleACS PublicationsRequest reuse permissionsArticle Views72Altmetric-Citations8LEARN 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
On-column electrochemical detector with a single graphite fiber electrode for open-tubular liquid chromatography (1984)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn-column electrochemical detector with a single graphite fiber electrode for open-tubular liquid chromatographyLaurance A. Knecht, Edward J. Guthrie, and James W. JorgensonCite this: Anal. Chem. 1984, 56, 3, 479–482Publication Date (Print):March 1, 1984Publication History Published online1 May 2002Published inissue 1 March 1984https://doi.org/10.1021/ac00267a042RIGHTS & PERMISSIONSArticle Views227Altmetric-Citations188LEARN 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 InReddit PDF (1 MB) Get e-Alerts Get e-Alerts
The geometry of GPS solutions (1992)

The geometry of point estimates of position computed
from GPS pseudoranges is studied, and a new geometric
model for GPS solutions is introduced. The new view-
point is a departure from the standard idea of what con-
stitutes a GPS solution in that the dependence of position
on user clock bias is explicitly treated. GPS solutions,
consisting of user position-user clock bias pairs, are seen
to lie at the intersection of unit cones positioned according
to the pseudorange measurements and satellite locations.
One benefit of treating the bias dependence so explic-
itly is that it makes clear the relationship between PDOP
and TDOP by exhibiting the geometric relationship be-
tween bias and position. It demonstrates the relation-
ship between ranging, pseudoranging, and time of arrival
differencing systems both qualitatively and with explicit
error estimates.
Highly Disordered Polymer Field Effect Transistors: <i>N</i>-Alkyl Dithieno[3,2-<i>b</i>:2′,3′-<i>d</i>]pyrrole-Based Copolymers with Surprisingly High Charge Carrier Mobilities (2008)

A series of novel electroactive and photoactive conjugated copolymers based on N-alkyl dithieno[3,2-b:2',3'-d]pyrroles (DTP) and thiophene (TH) units (DTP-co-THs) were synthesized using a Stille coupling reaction and exhibited molecular weights of 1.6 x 10(4) to 5.0 x 10(4) g/mol. The incorporation of soluble substituted thiophenes and planar DTP units resulted in low band gap, highly conductive polymers. DTP-co-THs exhibited excellent solubility in common organic solvents and formed high-quality films. Optical characterization revealed that the band gaps of DTP-co-THs were between 1.74 and 2.00 eV, lower than regioregular poly(3-alkylthiophenes). Electrochemical characterization showed that the HOMO energy levels of DTP-co-THs are between -4.68 and -4.96 eV. When doped, DTP-co-THs exhibited high conductivities up to 230 S/cm with excellent stability. The different thiophene substituent patterns' effect on the polymers' optical and electronic properties was then examined by density functional theory computations. The microstructure and surface morphologies of poly(2,6-(4-dodecyl-4H-bisthieno[3,2-b:2',3'-d]pyrrole)-random-2,5-(3-dodecylthiophene)) (P4) and poly(2-(4,4'-didodecyl-2,2'-bithiophen-5-yl)-4-octyl-4H-bisthieno[3,2-b:2',3'-d]pyrrole) (P6) thin films were studied by X-ray diffraction and atomic force microscopy. As-cast P4 and P6 thin films exhibited poorly defined, randomly ordered lamellar structure that improved significantly after thermal annealing. Field effect transistor devices fabricated from P4 and P6 showed typical p-channel transistor behavior. Interestingly, the mobilities of as-cast, less ordered samples were much higher than those observed after annealing. The highest values of maximum and average mobilities were observed for the polymer P6 as-cast (0.21 and 0.13 cm(2) V(-1) s(-1), respectively). One of our goals was to test the idea that high mobility and excellent electrical and structural reproducibility could perhaps be achieved by the creation of amorphous pi-conjugated materials that could possess long arrange pi connectivity on the microscopic scale. The results of these studies strongly suggest that the presence of highly ordered microcrystalline structures in thin films of organic semiconductors is not necessary for excellent performance of organic transistors.
Precision terrain mapping using large baseline interferometry (2002)

Veridian ERIM International, with support from the US Air Force and the Defense Advanced Research Projects Agency Tactical Technology Office (DARPA/TTO), has developed an airborne X-band SAR system capable of collecting single-pass interferometric SAR data with cross-track baselines of 7.5 m, 15 m, and 30 m. SAR data have been collected over several sites with varying terrain and groundcover type. These data have been formed into 1-foot resolution imagery and interferometric processing has produced digital elevation data with post spacings of 1 m. The resulting elevation data have been compared with LIDAR elevation data in order to estimate the accuracy of the SAR elevation measurements. SAR elevation data with accuracy approaching the draft Level 5 specification for precision elevation data have been produced.
Content and bioavailability of organic forms of nitrogen in the O horizon of a podzol (1999)

Summary It is often thought that the most important source of nitrogen for plants and microorganisms comes from amino acids and amino sugars when they are hydrolysed in acid conditions. We did a microcosm experiment to test the hypothesis. In the experiment spruce seedlings ( Picea abies L. Karst) were grown for 145 days in soil taken from a podzol Oa horizon under a long‐term nitrogen fertilization experiment (control and N‐treated soil). Net changes in different pools of organic N were determined using standard fractionation (acid hydrolysis and pyrophosphate extraction). During the experiment the amino acid and amino sugar pools decreased significantly (14% and 15% for the control and 10% and 17% for the N treatment), whereas no significant change was observed in the non‐amino acid plus non‐amino sugar fraction. On a per organic C basis there was even a significant increase in the non‐amino acid plus non‐amino sugar fraction of 11% for the control and 8% for the N treatment. Pyrophosphate extractions suggest that amino acids or amino sugars associated with the humin fraction were more accessible to microbes and plants than those associated with the humic acid, fulvic acid and hydrophilic substances. The long‐term N fertilization (about 73 kg N ha −1 was added annually as NH 4 NO 3 during a 24‐year period) resulted in an enrichment of all major fractions of organic N, i.e. amino acids, amino sugars and non‐amino acids plus non‐amino sugars. This enrichment was largely the result of small increases in all of the amino acids rather than large increases in just a few.
Tensile strain dependence of Brillouin frequency shift in silica optical fibers (1989)

Brillouin frequency shift in a single-mode optical fiber has been measured as a function of tensile strain. The strain coefficient of normalized Brillouin frequency shift C identical to (dv/sub B//d epsilon )/v/sub B/ is found to be 4.4 for silica fibers. This result shows the potential of Brillouin spectroscopy to evaluate tensile strain in the fiber with the strain resolution of about 2*10/sup -4/. The origin of the large strain coefficient is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>