gebhart/patrepeval huggingface dataset:
Non‐contrast‐enhanced vascular magnetic resonance imaging using flow‐dependent preparation with subtraction (2011)

Recent concerns over contrast agent safety have encouraged new developments in non-contrast-enhanced vascular imaging techniques. This work investigates the potential for imaging both arteries and veins with vascular anatomy by nonenhanced static subtraction angiography (VANESSA), a method using controllable flow suppression together with subtraction of bright- and dark-blood images. The lower legs of eight healthy volunteers and three patients were imaged using a modified motion-sensitized driven equilibrium preparation, with three-dimensional balanced steady-state free precession readout. The vascular signal decreased with increasing motion-suppression gradient amplitude, and was suppressed when the velocity-encoding parameter was (approximately) less than the measured flow velocity. Selected pairs of images were subtracted to depict vessels with either fast flow (e.g. arteries), slow flow (e.g. veins), or both. Several methodological modifications improved image quality and reduced the background signal from static tissues. Subjectively assessed image quality in volunteers was rated as excellent for 56/64 arterial segments, and good or excellent for 35/64 veins. In conclusion, VANESSA enables rapid non-contrast-enhanced imaging of arteries and veins, combining information on both morphology and flow. This study demonstrates good technical performance in volunteers and evaluation in patients with vascular disease is warranted.
Molecular beacons can assess changes in expression and 3′-polyadenylation of human eNOS mRNA (2008)

The endothelium plays an essential role in maintaining vascular homeostasis, and it fulfills this role by modulating intracellular signaling and gene expression in response to chemical and mechanical stimuli. Assessing changes in endothelial gene expression is essential to understanding how physiological and pathophysiological processes modulate vascular homeostasis. Here we describe the use of molecular beacons to rapidly and quantitatively assess expression and 3'-polyadenylation of a gene that is important for vascular homeostasis, endothelial nitric oxide synthase (eNOS). Single- and dual-fluorescence resonance energy transfer (FRET) molecular beacon hybridization assays were developed to measure changes in mRNA levels and 3'-polyadenylation, respectively, in primary human endothelial cell cultures subjected to laminar shear stress or statin treatment. Optimized beacon hybridization assays took approximately 15 min to perform, and eNOS mRNA levels were validated by quantitative real-time RT-PCR. Competitive inhibition assays and posttranscriptional silencing of eNOS expression were used to verify the specificity of molecular beacon fluorescence. Finally, the dual-FRET method was used to assess eNOS polyadenylation in tissues isolated from mice subjected to exercise training. These data demonstrate that molecular beacons can be used to rapidly and efficiently measure endothelial gene expression and 3'-polyadenylation. This approach could easily be adapted for studies of other endothelial genes and has promise for applications in live endothelial cells.
Identification and Analysis of Genes Involved in Anaerobic Toluene Metabolism by Strain T1: Putative Role of a Glycine Free Radical (1998)

The denitrifying strain T1 is able to grow with toluene serving as its sole carbon source. Two mutants which have defects in this toluene utilization pathway have been characterized. A clone has been isolated, and subclones which contain tutD and tutE, two genes in the T1 toluene metabolic pathway, have been generated. The tutD gene codes for an 864-amino-acid protein with a calculated molecular mass of 97,600 Da. The tutE gene codes for a 375-amino-acid protein with a calculated molecular mass of 41,300 Da. Two additional small open reading frames have been identified, but their role is not known. The TutE protein has homology to pyruvate formate-lyase activating enzymes. The TutD protein has homology to pyruvate formate-lyase enzymes, including a conserved cysteine residue at the active site and a conserved glycine residue that is activated to a free radical in this enzyme. Site-directed mutagenesis of these two conserved amino acids shows that they are also essential for the function of TutD.
Valenzisomerisierung perhalogenierter 4‐Methylen‐bicyclo[3.2.0]hepta‐2,6‐diene zu Heptafulvenen (1978)

Abstract Die Synthese gemischter brom‐ und chlorsubstituierter 4‐Methylen‐bicyclo[3.2.0]hepta‐2,6‐diene 6b, c aus Hexachlorcyclopentadien und entsprechenden Trihalogenethylenen wird beschrieben. Die Valenzisomerisierung 6a → 7 ist reversibel. Thermisch (bei 340 °C) entsteht 7 aus 6a. doch lagert es sich weiter in die stabileren aromatischen Produkte 8 und 9 um. Photochemisch wird 7 sowohl zu 6a als auch zu 8 isomerisiert. Die Kurzzeitthermolyse von 6b bei 460°C ist mit einem Brom/Chlor‐Austausch verbunden und liefert ein Gemisch der Heptafulvene 7, 10 und 11 , während aus 6c unter den gleichen Bedingungen das reine Heptafulven 12 erhalten werden konnte.
Molecular Dynamics Simulation Study of a Polysulfone-Based Anion Exchange Membrane in Comparison with the Proton Exchange Membrane (2014)

We investigate two types of polysulfone-based membranes (quaternary ammonium-functionalized anion exchange membrane and sulfonated proton exchange membrane) using molecular dynamics simulations to compare their nanophase-segregated structures and transport properties. Although the distribution of ionic groups on the polymer backbone is similar for both types, the quaternary ammonium groups and hydroxide ions in the anion exchange membrane are more solvated by water compared to the sulfonate groups and hydronium ions in the proton exchange membrane. Correspondingly, such better solvation of the ammonium groups and hydroxide ions leads the internal structure to a less matured hydrogen bonding network in the water phase, especially at low water content conditions. Through analysis of the nanophase segregation of the membranes, it is found that the characteristic correlation length has a similar value for both membranes, whereas the concentration contrast between the polymer domain and water phase is more distinct in the anion exchange membrane relative to the proton exchange membrane. Within such nanophase-segregated structures, it is found that the diffusion of hydroxide is ∼6% and ∼11% of that of hydronium at 10 and 20 wt % of water content, respectively, which might be due to the strong correlation at ∼4 Å among the hydroxide in the anion exchange membrane.
Interactions between Residues in Staphylococcal α-Hemolysin Revealed by Reversion Mutagenesis (1995)

alpha-Hemolysin (alpha HL), a pore-forming polypeptide of 293 amino acids, is secreted by Staphylococcus aureus as a water-soluble monomer. Residues that play key roles in the formation of functional heptameric pores on rabbit red blood cells (rRBC) have been identified previously by site-directed mutagenesis. alpha HL-H35N, in which the histidine at position 35 of the wild-type sequence is replaced with asparagine, is nonlytic and is arrested in assembly as a heptameric prepore. In this study, second-site revertants of H35N that have the ability to lyse rRBC were generated by error-prone PCR under conditions designed to produce single base changes. The analysis of 22 revertants revealed new codons clustered predominantly in three distinct regions of the H35N gene. One cluster includes amino acids 107-111 (four revertants) and another residues 144-155 (five revertants). These two clusters flank the central glycine-rich loop of alpha HL, which previously has been implicated in formation of the transmembrane channel, and encompass residues Lys-110 and Asp-152 that, like His-35, are crucial for lytic activity. The third cluster lies in the region spanning amino acids 217-228 (eight revertants), a region previously unexplored by mutagenesis. Single revertants were found at amino acid positions 84 and 169. When compared with H35N, the heptameric prepores formed by the revertants underwent more rapid conversion to fully assembled pores, as determined by conformational analysis by limited proteolysis. The rate of conversion to the fully assembled pore was strongly correlated with hemolytic activity. Previous work has suggested that the N terminus of alpha HL and the central loop cooperate in the final step of assembly. The present study suggests that the key N-terminal residue His-35 operates in conjunction with residues flanking the loop and C-terminal residues in the region 217-228. Hence, reversion mutagenesis extends the linear analysis that has been provided by direct point mutagenesis.
Optical head and optical disk technologies for HD DVD (2005)

Presented here are new optical head and optical disk technologies for an HD DVD system. The former include DVD- and CD-compatible optics and a radial tilt detection method, while the latter include new "low-to-high" media and the application of HD DVD rewritable disk format specifications.
Human Metapneumovirus Persists in BALB/c Mice despite the Presence of Neutralizing Antibodies (2004)

Human metapneumovirus (HMPV) has emerged as an important human respiratory pathogen causing upper and lower respiratory tract infections in young children and older adults. Recent epidemiological evidence indicates that HMPV may cocirculate with respiratory syncytial virus, and HMPV infection has been associated with other respiratory diseases. In this study, we show that BALB/c mice are susceptible to HMPV infection, the virus replicates in the lungs with biphasic growth kinetics in which peak titers occur at days 7 and 14 postinfection (p.i.), and infectious HMPV can be recovered from lungs up to day 60 p.i. In addition, we show that genomic HMPV RNA can be detected in the lungs for >/=180 days p.i. by reverse transcription-PCR; however, neither HMPV RNA nor infectious virus can be detected in serum, spleen, kidneys, heart, trachea, and brain tissue. Lung histopathology revealed prevalent mononuclear cell infiltration in the interstitium beginning at day 2 p.i. and peaking at day 4 p.i. which decreased by day 14 p.i. and was associated with airway remodeling. Increased mucus production evident at day 2 p.i. was concordant with increased bronchial and bronchiolar inflammation. HMPV-specific antibodies were detected by day 14 p.i., neutralizing antibody titers reached >/=6.46 log(2) end-point titers by day 28 p.i., and depletion of T cells or NK cells resulted in increased HMPV titers in the lungs, suggesting some immune control of viral persistence. This study shows that BALB/c mice are amenable for HMPV studies and indicates that HMPV persists as infectious virus in the lungs of normal mice for several weeks postinfection.
Synthesis of Some Stable 7-Halo-1,4-thiazepines. Potential Substituted Penam Precursors (1971)

The synthesis of some new 3-carbomethoxy-5-oxoperhydro-1,4-thiazepines is described. Halogenation studies led to the preparation of three potential substituted penam ring precursors: 6,7-dibromo-3-carbomethoxy-5-oxoperhydro-1,4-thiazepine, 3-carbomethoxy-6,7-dichloro-5-oxoperhydro-1,4-thiazepine, and 3-carbomethoxy-7-chloro-6,6-dimethyl-5-oxoperhydro-1,4-thiazepine. Preliminary studies on the reactivity of these α-halothioethers showed that methanolysis to the corresponding methoxy-thiazepines may be carried out in nearly quantitative yields in the case of the first two derivatives; the third compound, on the other hand, led to an open-chain dehydrohalogenated product where C-7 is converted to the corresponding dimethyl acetal.
Carbon monoxide low-temperature oxidation over nanosize gold catalyst (2002)

Gold has long been known as being catalytically inactive. However, more interest and attention have been concentrated on the research and development of gold catalysts in recent years. Gold catalysts have been shown good catalytic performances, especially for CO oxidation, and can be used to eliminate CO even below ambient temperature. Compared with other catalysts for CO oxidation, the nanosize gold catalysts have superior catalytic behaviors, such as high catalytic activity, high catalytic stability and high resistance to moisture, and show a continuously increasing and more extensive application prospects. In this review, the preparation factors such as preparation method, supports particle size, pretreatment condition were summarized. The activation and reaction mechanisms were discussed.
Studies of specifically fluorinated carbohydrates. Part I. Nuclear magnetic resonance studies of hexopyranosyl fluoride derivatives (1969)

A detailed study has been made of both the 1 H and 19 F nuclear magnetic resonance (n.m.r.) spectra of a series of hexopyranosyl fluoride derivatives. Some of the 1 H spectra were measured at 220 MHz. The 1 H spectral parameters define both the configuration and the conformation of each of these derivatives. Study of the 19 F n.m.r. parameters revealed several stereospecific dependencies. The 19 F chemical shifts depend upon, (a) the orientation of the fluorine substituent with respect to the pyranose ring and, (b) the relative orientation of other substituents attached to the ring; for acetoxy substituents, these configurational dependencies appear to be additive. The vicinal 19 F– 1 H coupling constants exhibit a marked angular dependence for which J trans = ca. 24 Hz whilst J gauche = 1.0 to 1.5 Hz for [Formula: see text] and 7.5 to 12.6 Hz for [Formula: see text] The geminal 19 F– 1 H couplings depend on the orientation of the substituent at C-2; when this substituent is equatorial J F,H is ca. 53.5 Hz and when it is axial the value is ca. 49 Hz.
Effect of Pulp Reduction and Pasteurization on the Release of Aroma Compounds in Industrial Orange Juice (2007)

Release of aroma compounds in orange juice according to pulp content and pasteurization was performed by headspace-solid phase microextraction (HS-SPME), HS-SPME-GC-olfactometry, and by the determination of partition coefficients of aroma compounds between the juice and the headspace. Orange juices with 12% and 6% pulp contents were collected from a processing line before and after pasteurization. HS-SPME revealed that the 6% pulp juice was the most affected by pasteurization, with an increase in the release of several aroma compounds that are generated by heat treatment (that is, alpha- and beta-terpinéol) and a decrease in the release of compounds sensitive to pasteurization (that is, neral and geranial). Principal component analysis of olfactometric data allowed discriminating fresh and pasteurized juices, regardless of the pulp content. The determination of the gas/liquid partition coefficients by the phase ratio variation method was possible for 7 aroma compounds. For the most hydrophobic ones, the release of aroma compounds in fresh juices was higher in the 6% pulp juice than in the 12% pulp juice. However, in pasteurized juices, the difference between their partition coefficients was less marked. Potential interactions between cloud proteins and hydrophobic aroma compounds may explain this phenomenon.
ATP-Dependent Inactivation and Sequestration of Ornithine Decarboxylase by the 26S Proteasome Are Prerequisites for Degradation (1999)

The 26S proteasome is a eukaryotic ATP-dependent protease, but the molecular basis of its energy requirement is largely unknown. Ornithine decarboxylase (ODC) is the only known enzyme to be degraded by the 26S proteasome without ubiquitinylation. We report here that the 26S proteasome is responsible for the irreversible inactivation coupled to sequestration of ODC, a process requiring ATP and antizyme (AZ) but not proteolytic activity. Neither the 20S proteasome (catalytic core) nor PA700 (the regulatory complex) by itself contributed to this ODC inactivation. Analysis with a C-terminal mutant ODC revealed that the 26S proteasome recognizes the C-terminal degradation signal of ODC exposed by attachment of AZ, and subsequent ATP-dependent sequestration of ODC in the 26S proteasome causes irreversible inactivation, possibly unfolding, of ODC and dissociation of AZ. These processes may be linked to the translocation of ODC into the 20S proteasomal inner cavity, centralized within the 26S proteasome, for degradation.
SHV-1 β-Lactamase Is Mainly a Chromosomally Encoded Species-Specific Enzyme in <i>Klebsiella pneumoniae</i> (2001)

The nature of the SHV-1 beta-lactamase gene was analyzed in 97 epidemiologically unrelated Klebsiella pneumoniae strains isolated from clinical samples. beta-Lactamase bands that focused at a pI of 7.6 (SHV-1-type) in 74 strains, at a pI of 7.1 (LEN-1-type) in 13 strains, and at a pI of 5.4 (TEM-1-type) in 10 strains were detected by analytical isoelectric focusing (IEF). Among the 74 SHV-1-producing strains, 40 had, in addition to the pI 7.6 band, an additional band on IEF: 20 had a band with a pI of 7.1 and 20 had a band with a pI of 5.4. Most of the 74 SHV-1-producing strains (76.7%) carried plasmids. Transfer of beta-lactam resistance by conjugation was possible in only 9.3% of the strains tested. SHV-1 gene-specific PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the chromosomal DNA was positive for 93 of the 97 strains and negative for only 4 of the 10 samples with K. pneumoniae TEM-1 producers. In an attempt to approximate the location of the SHV gene locus by endonuclease restriction analysis, RFLP analysis with Southern blotting of chromosomal DNA with a labeled SHV-1 fragment as a probe was used to study the 97 strains. A trial with EcoRI showed at least one positive hybridization band for 96 strains; two bands were detected for 8 strains. The hybridization was negative for only one TEM-1 beta-lactamase-producing strain. DNA sequence analysis showed no differences in promoter regions or extra stop-triplet sequences; only point mutations determined different allelic variants. The novel SHV-type variants are designated SHV-32 and SHV-33. As a result of the RFLP and sequencing analyses, it can be postulated that the loci for SHV-1 and LEN-1 genes are arranged in tandem. Our results strongly support the hypothesis that the ancestor of the SHV-1 beta-lactamase originated from the K. pneumoniae chromosome.
Skin Color Detection Model Using Neural Networks and its Performance Evaluation (2010)

Problem statement: Skin color detection is used as a preliminary step in numerous computer vision applications like face detection, nudity recognition, hand gesture detection and person identification. In this study we present a pixel based skin color classification approach, for detecting skin pixels and non skin pixels in color images, using a novel neural network symmetric classifier. The neural classifiers used in the literature either uses a symmetric model with single neuron in the output layer or uses two separate neural networks (asymmetric model) for each of the skin and non-skin classes. The novelty of our approach is that it has two output layer neurons; one each for skin and non-skin class, instead of using two separate classifiers. Thus by using a single neural network classifier we have improved the separability between these two classes, eliminating additional time complexity that is needed in asymmetric classifier. Approach: Skin samples from web images of people from different ethnic groups were collected and used for training. Ground truth skin segmented images were obtained by using semiautomatic skin segmentation tool developed by the authors. The ground truth database of skin segmented images, thus obtained was used to evaluate the performance of our NN based classifier. Results: With proper selection of optimum classification threshold that varies from image to image the classifier gave the detection rate of more than 90% with 7% false positives on an average, Conclusion/Recommendations: It is observed that the neural network is capable of detecting skin in complex lighting and background environments. The classifier has the ability to classify the skin pixels belonging to people from different ethnic groups even when they are present simultaneously in an image. The proper choice of optimum classification threshold that varies from image to image is an issue here. Automatic computation of this optimum threshold for each image is desired in practical skin detection applications. This issue can be taken up as a future study, which will enable us to perform fully automatic skin segmentation with reduced false positives.
Access Control of Web and Java Based Applications (2011)

Cyber security has gained national and international attention as a result of near continuous headlines from financial institutions, retail stores, government offices and universities reporting compromised systems and stolen data. Concerns continue to rise as threats of service interruption, unauthorized access, stealing and altering of information, and spreading of viruses become ever more prevalent and serious. Controlling access to application layer resources is a critical component in a layered security solution that includes encryption, firewalls, virtual private networks, antivirus, and intrusion detection. In this paper we discuss the development of an application-level access control solution, based on an open-source access manager augmented with custom software components, to provide protection to both Web-based and Java-based client and server applications.
A new intensity-hue-saturation fusion approach to image fusion with a tradeoff parameter (2006)

A useful technique in various applications of remote sensing involves the fusion of panchromatic and multispectral satellite images. Recently, Tu et al. introduced a fast intensity-hue-saturation (IHS) fusion method. Aside from its fast computing capability for fusing images, this method can extend traditional three-order transformations to an arbitrary order. It can also quickly merge massive volumes of data by requiring only resampled multispectral data. However, fast IHS fusion also distorts color in the same way as fusion processes such as the IHS fusion technique. To overcome this problem, the minimization problem for a fast IHS method was considered and the method proposed by Gonza/spl acute/lez-Aud/spl inodot//spl acute/cana et al. is presented as a solution. However, the method is not efficient enough to quickly merge massive volumes of data from satellite images. The author therefore uses a tradeoff parameter in a new approach to image fusion based on fast IHS fusion. This approach enables fast, easy implementation. Furthermore, the tradeoff between the spatial and spectral resolution of the image to be fused can be easily controlled with the aid of the tradeoff parameter. Therefore, with an appropriate tradeoff parameter, the new approach provides a satisfactory result, both visually and quantitatively.