gebhart/patrepeval huggingface dataset:
Binding and Degradation of Low Density Lipoproteins by Cultured Human Fibroblasts (1974)

125I-Labeled low density lipoproteins were found to associate with monolayers of cultured normal fibroblasts by two processes—one of high affinity and one of low affinity. The high affinity association appeared to represent binding of the low density lipoprotein to specific receptor sites on the cell surface. This binding process exhibited saturation kinetics at low concentrations of the lipoprotein and competition by related molecules such as very low density lipoproteins. In addition, this process was stimulated by the presence of calcium in the culture medium and could be destroyed by limited treatment of the cells with pronase. The other process, designated low affinity uptake, may represent nonspecific endocytosis since the uptake was proportional to the lipoprotein concentration in the medium with no apparent saturation and because it showed no competition by very low density lipoproteins, no stimulation by calcium, and no destruction by pronase treatment. The 125I-labeled low density lipoproteins associated with normal cells by either the high or low affinity process were degraded by proteolysis to trichloroacetic acid-soluble material, most of which was 125I-tyrosine. In normal cells, binding of low density lipoproteins to the high affinity membrane receptor sites appears to serve two functions: (a) it results in suppression of the synthesis of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-controlling enzyme in cholesterol biosynthesis, and (b) it facilitates the degradation of low density lipoproteins when they are present in the culture medium at low concentrations (i.e. high affinity degradation). Cultured cells from subjects with the homozygous form of familial hypercholesterolemia, which were found to lack the high affinity binding process, were resistant to suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity by low density lipoproteins and were also deficient in high affinity degradation. On the other hand, these mutant cells showed a normal low affinity uptake of low density lipoproteins and were able to degrade these lipoproteins when they were present in the culture medium at high concentrations. The possibility is raised, therefore, that a prerequisite for the regulation of cholestero-genesis in cultured fibroblasts is the initial binding of low density lipoproteins to the high affinity surface receptor sites and that a defect in this process represents the primary genetic abnormality in the disorder familial hypercholesterolemia.
Synthesis of PbS nanoparticles in polymer matrices (1994)

A new kind of PbS nanoparticles/polymer composite is synthesized whose microstructure observed under TEM proves that the nanoparticles are well dispersed and even in size; electron diffraction results identify the PbS nanoparticles to be of the cubic rock salt structure, and the particle size can be varied from 4 to 11 nm.
Investigation of Cosolute−Protein Preferential Interaction Coefficients: New Insight into the Mechanism by Which Arginine Inhibits Aggregation (2009)

The relatively new technique of vapor pressure osmometry was utilized to determine the preferential interaction of five common solution additives (arginine HCl, guanidine HCl, glycerol, glucose, and urea) using three different model proteins (BSA, lysozyme, and alpha-chymotrypsinogen). Results for guanidine, glycerol, glucose, and urea are comparable to literature values, which utilized the dialysis/densimetry technique. However, values for arginine differ greatly from literature values, making it unclear what is the nature of arginine-protein interactions. A repeat of the dialysis/densimetry measurements reported in the literature supports the vapor pressure osmometry measurements and reveals a never before seen trend in the interaction of arginine with proteins as a function of concentration. This trend is dependent on the protein size and shows arginine to be unique among solution additives. For concentrations below 0.5 M, arginine has a preferential interaction coefficient near zero (slightly greater than zero for small proteins but decreases as the size of the protein increases), which indicates that arginine is neither strongly bound nor excluded from the protein surface. This trend differs greatly from cosolutes that influence the protein folding equilibrium. However, as the concentration of arginine increases beyond 0.5 M, arginine becomes increasingly excluded. Such behavior might be indicative of the protein surface becoming saturated with arginine, thus causing any additional arginine added to the solution to be excluded from interacting with the surface. All of this behavior is most likely the result of a balance between the affinity arginine has for the peptide backbone and certain amino acids and the repulsion generated by surface tension increment and volume exclusion effects [Arakawa et al. Biophysical Chemistry 2007, 127, 1]. In addition, such behavior may explain why arginine has little effect on protein folding equilibrium but is an effective aggregation suppressor.
Dielectrophoretic isolation of DNA and nanoparticles from blood (2012)

The ability to effectively detect disease-related DNA biomarkers and drug delivery nanoparticles directly in blood is a major challenge for viable diagnostics and therapy monitoring. A DEP method has been developed which allows the rapid isolation, concentration and detection of DNA and nanoparticles directly from human and rat whole blood. Using a microarray device operating at 20 V peak-to-peak and 10 kHz, a wide range of high molecular weight (HMW)-DNA and nanoparticles were concentrated into high-field regions by positive DEP, while the blood cells were concentrated into the low-field regions by negative DEP. A simple fluidic wash removes the blood cells while the DNA and nanoparticles remain concentrated in the DEP high-field regions where they can be detected by fluorescence. HMW-DNA could be detected at 260 ng/mL, which is a detection level suitable for analysis of disease-related cell-free circulating DNA biomarkers. Fluorescent 40 nm nanoparticles could be detected at 9.5 × 10(9) particles/mL, which is a level suitable for monitoring drug delivery nanoparticles. The ability to rapidly isolate and detect DNA biomarkers and nanoparticles from undiluted whole blood will benefit many diagnostic applications by significantly reducing sample preparation time and complexity.
Water Permeability of Asymmetric Planar Lipid Bilayers (2001)

To understand how plasma membranes may limit water flux, we have modeled the apical membrane of MDCK type 1 cells. Previous experiments demonstrated that liposomes designed to mimic the inner and outer leaflet of this membrane exhibited 18-fold lower water permeation for outer leaflet lipids than inner leaflet lipids (Hill, W.G., and M.L. Zeidel. 2000. J. Biol. Chem. 275:30176-30185), confirming that the outer leaflet is the primary barrier to permeation. If leaflets in a bilayer resist permeation independently, the following equation estimates single leaflet permeabilities: 1/P(AB) = 1/P(A) + 1/P(B) (Eq. l), where P(AB) is the permeability of a bilayer composed of leaflets A and B, P(A) is the permeability of leaflet A, and P(B) is the permeability of leaflet B. Using for the MDCK leaflet-specific liposomes gives an estimated value for the osmotic water permeability (P(f)) of 4.6 x 10(-4) cm/s (at 25 degrees C) that correlated well with experimentally measured values in intact cells. We have now constructed both symmetric and asymmetric planar lipid bilayers that model the MDCK apical membrane. Water permeability across these bilayers was monitored in the immediate membrane vicinity using a Na+-sensitive scanning microelectrode and an osmotic gradient induced by addition of urea. The near-membrane concentration distribution of solute was used to calculate the velocity of water flow (Pohl, P., S.M. Saparov, and Y.N. Antonenko. 1997. Biophys. J. 72:1711-1718). At 36 degrees C, P(f) was 3.44 +/- 0.35 x 10(-3) cm/s for symmetrical inner leaflet membranes and 3.40 +/- 0.34 x 10(-4) cm/s for symmetrical exofacial membranes. From, the estimated permeability of an asymmetric membrane is 6.2 x 10(-4) cm/s. Water permeability measured for the asymmetric planar bilayer was 6.7 +/- 0.7 x 10(-4) cm/s, which is within 10% of the calculated value. Direct experimental measurement of P(f) for an asymmetric planar membrane confirms that leaflets in a bilayer offer independent and additive resistances to water permeation and validates the use of.
Effects of Processing on the Structure of Zein/Oleic Acid Films Investigated by X‐Ray Diffraction (2005)

Zein films plasticized with oleic acid were formed by solution casting, by the stretching of moldable resins, and by blown film extrusion. The effects of the forming process on film structure were investigated by X-ray diffraction. Wide-angle X-ray scattering (WAXS) patterns showed d-spacings at 4.5 and 10 A, which were attributed to the zein alpha-helix backbone and inter-helix packing, respectively. The 4.5 A d-spacing remained stable under processing while the 10 A d-spacing varied with processing treatment. Small-angle X-ray scattering (SAXS) detected a long-range periodicity for the formed films but not for unprocessed zein, which suggests that the forming process-promoted film structure development is possibly aided by oleic acid. The SAXS d-spacing varied among the samples (130-238 A) according to zein origin and film-forming method. X-ray scattering data suggest that the zein molecular structure resists processing but the zein supramolecular arrangements in the formed films are dependent on processing methods. Structural model for a zein molecular aggregate (based on Matsushima et al.10). Rectangular prisms of individual zein molecules are hexagonally aligned parallel to each other.
Nonhuman primates as models for the discovery and development of ebolavirus therapeutics (2011)

Well-characterized models of ebolavirus infection are currently under development and scrutiny as to their accuracy and utility for modeling fatal infection in humans. The advanced development and eventual licensure of therapeutic agents will require demonstration that mechanisms conferring protection in nonhuman primate models of infection are predictive of protective responses in humans.
Development of a Steering Entropy Method for Evaluating Driver Workload (1999)

&lt;div class="htmlview paragraph"&gt;The authors have developed a steering entropy method to easily and accurately quantify the workload imposed on drivers who are engaged in activities apart from the normal driving operations of longitudinal and lateral control. A driver's steering behavior tends to become more discontinuous while performing an activity in addition to driving. To quantify these discontinuities, steering entropy values are obtained from a time-series history of steering angle data. A special-purpose driving simulator and a test procedure have been developed that allow workload evaluations to be conducted efficiently. The simulator and test procedure were used to evaluate the additional workload incurred by 14 different types of activities. The steering entropy results were compared with a dual task method as well as a subjective evaluation method. These results showed a high degree of correlation between the three approaches, which confirmed the validity of the steering entropy method as a means to quantify workload. Measurements were then made of progressively more difficult tasks. It was found that the steering entropy values increased in direct proportion to the degree of (subjective) task difficulty, which corroborated the high measurement accuracy of this method.&lt;/div&gt;
The Next Learning Adventure (2010)

New technologies are transforming experiential and inquiry-based learning by engaging students with remote cultures and environments. Andrew Hughes explains.
The Economic Burden of Non–Influenza-Related Viral Respiratory Tract Infection in the United States (2003)

Largely because of the high attack rate, non-influenza-related VRTI imposes a greater economic burden than many other clinical conditions. The pending availability of effective antiviral therapies warrants increased attention be paid to this common and expensive illness.
Why gold nanoparticles are more precious than pretty gold: Noble metal surface plasmon resonance and its enhancement of the radiative and nonradiative properties of nanocrystals of different shapes (2005)

This tutorial review presents an introduction to the field of noble metal nanoparticles and their current applications. The origin of the surface plasmon resonance and synthesis procedures are described. A number of applications are presented that take advantage of the electromagnetic field enhancement of the radiative properties of noble metal nanoparticles resulting from the surface plasmon oscillations.
Routing of internalized ricin and ricin conjugates to the Golgi complex. (1986)

Receptor-mediated endocytosis and intracellular routing of native ricin, and of ricin conjugated to colloidal gold (Ri-Au) and to horseradish peroxidase (Ri-HRP), have been studied in cultured MCF-7 and Vero cells by electron microscopical techniques including serial section analysis. Both native ricin, as demonstrated by immunoperoxidase cytochemistry, and the ricin conjugates were internalized via a common coated pit-coated vesicle pathway to reach vacuolar and tubulo-vesicular portions of the endosomal system. In addition, native ricin and a purified monovalent fraction of Ri-HRP reached distinct Golgi cisterns, whereas Ri-Au and polyvalent Ri-HRP did not. The results delineate intracellular routing of native ricin and compare it with the routing of different ricin conjugates. Moreover, our study shows that conjugates of a particular ligand (ricin) and various probes (e.g., gold and peroxidase), may be handled differently by cells. Sorting apparently takes place in the endosomal system, allowing some but not other molecules to reach Golgi elements. This sorting seems to depend on the valency of the ricin conjugate.
Molecular Analysis of the Sodium/Iodide Symporter: Impact on Thyroid and Extrathyroid Pathophysiology (2000)

The Na(+)/I(-) symporter (NIS) is an intrinsic membrane protein that mediates the active transport of iodide into the thyroid and other tissues, such as salivary glands, gastric mucosa, and lactating mammary gland. NIS plays key roles in thyroid pathophysiology as the route by which iodide reaches the gland for thyroid hormone biosynthesis and as a means for diagnostic scintigraphic imaging and for radioiodide therapy in hyperthyroidism and thyroid cancer. The molecular characterization of NIS started with the 1996 isolation of a cDNA encoding rat NIS and has since continued at a rapid pace. Anti-NIS antibodies have been prepared and used to study NIS topology and its secondary structure. The biogenesis and posttranslational modifications of NIS have been examined, a thorough electrophysiological analysis of NIS has been conducted, the cDNA encoding human NIS (hNIS) has been isolated, the genomic organization of hNIS has been elucidated, the regulation of NIS by thyrotropin and I(-) has been analyzed, the regulation of NIS transcription has been studied, spontaneous NIS mutations have been identified as causes of congenital iodide transport defect resulting in hypothyroidism, the roles of NIS in thyroid cancer and thyroid autoimmune disease have been examined, and the expression and regulation of NIS in extrathyroidal tissues have been investigated. In gene therapy experiments, the rat NIS gene has been transduced into various types of human cells, which then exhibited active iodide transport and became susceptible to destruction with radioiodide. The continued molecular analysis of NIS clearly holds the potential of an even greater impact on a wide spectrum of fields, ranging from structure/function of transport proteins to the diagnosis and treatment of cancer, both in the thyroid and beyond.
In Vivo Adduction and Reverse Axial Rotation (External) of the Tibial Component Can Be Minimized (2009)

Mechanical alignment with conventional total knee arthroplasty (TKA) instruments often requires collateral ligament releases, which result in a high prevalence of adduction and reverse axial rotation (external rotation) of the tibial component during knee flexion with a variety of component designs. We used a radiographic image-matching technique to determine the contact kinematics during standing and kneeling at 90 degrees and maximum flexion in a series of 35 patients in which a new image-guided, custom cutting block system was used to kinematically align a cruciate-retaining prosthesis with the intent of restoring the 3 kinematic axes of the knee. The kinematically aligned prosthesis had a minimal prevalence of adduction (3%) and reverse axial rotation (8.5%). The anteroposterior contact positions of the lateral and medial femoral condyles did not edge load the tibial liner. The moderate association between abduction and internal rotation, the degree of knee flexion, and the contact position of the medial femoral condyle suggest that abduction was not a sign of lift-off of the medial femoral condyle, but the result of the medial femoral condyle moving up the anterior slope of the tibial liner. These more normal contact kinematics were achieved without release of the collateral ligaments or lateral retinaculum. In contrast to mechanical alignment with conventional surgical techniques, the use of kinematic alignment with custom-fit cutting guides and a cruciate-retaining, symmetric medial and lateral femoral-tibial bearing surface minimizes the undesirable consequences of adduction and reverse axial rotation (external rotation).
The Periplasmic Escherichia coli Peptidylprolyl cis,trans-Isomerase FkpA (2000)

We recently identified FkpA by selecting for the increased yield of antibody single-chain Fv (scFv) fragments in phage display, even of those not containing cis-prolines. We have now investigated the properties of FkpA in vitro. The peptidylprolyl cis-trans-isomerase activity of FkpA was found to be among the highest of any such enzyme with a protein substrate, yet FkpA is not able to enhance the proline-limited refolding rate of the disulfide-free hu4D5-8 scFv fragment, probably due to inaccessibility of Pro-L95. Nevertheless, the yield of the soluble and functional scFv fragment was dramatically increased in vitro in the presence of FkpA. Similar effects were observed for an scFv fragment devoid of cis-prolines. We are thus forced to conclude that the observed folding-assisting function is independent of the isomerase activity of the protein. The beneficial effect of FkpA was found to be due to two components. First, FkpA interacts with early folding intermediates, thus preventing their aggregation. Additionally, it has the ability to reactivate inactive protein, possibly also by binding to a partially unfolded species that may exist in equilibrium with the aggregated form, which may thus be released on a productive pathway. These in vitro measurements therefore fully reflect the in vivo results from periplasmic overexpression of FkpA.
Multiple Reaction Monitoring to Identify Sites of Protein Phosphorylation with High Sensitivity (2005)

Phosphorylation governs the activity of many proteins. Insight into molecular mechanisms in biology would be immensely improved by robust, sensitive methods for identifying precisely sites of phosphate addition. An approach to selective mapping of protein phosphorylation sites on a specific target protein of interest using LC-MS is described here. In this approach multiple reaction monitoring is used as an extremely sensitive MS survey scan for potential phosphopeptides from a known protein. This is automatically followed by peptide sequencing and subsequent location of the phosphorylation site; both of these steps occur in a single LC-MS run, providing greater efficiency of sample use. The method is capable of detecting and sequencing phosphopeptides at low femtomole levels with high selectivity. As proof of the value of this approach in an experimental setting, a key Schizosaccharomyces pombe cell cycle regulatory protein, Cyclin B, was purified, and associated proteins were identified. Phosphorylation sites on these proteins were located. The technique, which we have called multiple reaction monitoring-initiated detection and sequencing (MIDAS), is shown to be a highly sensitive approach to the determination of protein phosphorylation.
One- and two-dimensional31P NMR characterization of pure phosphate chelates in cytidine-5′-di- and -tri-phosphatoplatinum(II) complexes (1990)

cis-Diamminedichloroplatinum(II) treated with CTP and CDP yields phosphate chelates as the major products; the chelates are diastereoisomers (Λ and Δ) formed by co-ordination through the two adjacent phosphate groups of the nucleotides, diplatinum complexes in which two nucleotide molecules bridge platinum centres through N(3) and terminal phosphate co-ordination in a ‘head-to-tail’ fashion are the minor products, these dinuclear complexes are the dominant products of the same reactions when cis-diamminediaquaplatinum(II) cation is used.
The Association between Negative Symptoms, Psychotic Experiences and Later Schizophrenia: A Population-Based Longitudinal Study (2015)

Negative symptoms are common in the general population, though the majority of people with negative symptoms do not manifest a clinically diagnosed psychiatric disorder. Negative symptoms and psychotic experiences critically depend on each other's co-occurrence in increasing risk for later schizophrenia.
Angiogenesis in the central nervous system: a role for vascular endothelial growth factor/vascular permeability factor and tenascin-C. Common molecular effectors in cerebral neoplastic and non-neoplastic "angiogenic diseases". (2002)

Human pathological conditions of the central nervous system (CNS) associated with angiogenesis (i.e. neovascularization) include neoplastic, as well as infectious, ischemic, and traumatic processes. Upregulation of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and tenascin-C (TN-C) is spatially and temporally related to neovascularization. Spatially, VEGF/VPF and TN-C are both found at the site of neovascularization, but they are not detected in areas of normal brain or in areas without neovascularization. Temporally, VEGF/VPF and TN-C are found at the peak of angiogenesis and are not detected when angiogenesis had ceased.
A flexible capacitive tactile sensing array with floating electrodes (2009)

In this work, we present the development of a capacitive tactile sensing array realized by using MEMS fabrication techniques and flexible printed circuit board (FPCB) technologies. The sensing array, which consists of two micromachined polydimethlysiloxane (PDMS) structures and a FPCB, will be used as the artificial skin for robot applications. Each capacitive sensing element comprises two sensing electrodes and a common floating electrode. The sensing electrodes and the metal interconnect for signal scanning are implemented on the FPCB, while the floating electrode is patterned on one of the PDMS structures. This special design can effectively reduce the complexity of the device structure and thus makes the device highly manufacturable. The characteristics of the devices with different dimensions are measured and discussed. The corresponding scanning circuits are also designed and implemented. The tactile images induced by the PMMA stamps of different shapes are also successfully captured by a fabricated 8 × 8 array.