gebhart/patrepeval huggingface dataset:
Toxicity of Silver Nanoparticles Increases during Storage Because of Slow Dissolution under Release of Silver Ions (2010)

The dissolution of citrate-stabilized and poly(vinylpyrrolidone)-stabilized silver nanoparticles in water was studied by dialysis for up to 125 days at 5, 25, and 37 °C. The particles slowly dissolve into ions on a time scale of several days. However, in all cases, a limiting value of the released silver was observed, i.e., the particles did not completely dissolve. In some cases, the nanoparticles released up to 90% of their weight. Formal kinetic data were computed. Rate and degree of dissolution depended on the functionalization as well as on the storage temperature. The release of silver led to a considerably increased toxicity of silver nanoparticles which had been stored in dispersion for several weeks toward human mesenchymal stem cells due to the increased concentration of silver ions. Consequently, “aged” (i.e., immersed) silver nanoparticles are much more toxic to cells than freshly prepared silver nanoparticles.
Purification and kinetic properties of guinea pig liver .BETA.-mannosidase. (1985)

β-Mannosidase was purified to electrophoretic homogeneity from the 20000g supernatant of guinea pig liver homogenate. A highly purified enzyme preparation was also obtained from the acetone powder. This enzyme had a pH optimum of 4.0 and molecular weights of ca. 120000 as determined by gel filtration and 110000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was free from other glycosidase activities, as far as was tested. The enzymatic hydrolysis of o- and p-nitrophenyl β-mannosides exhibited an unusual relationship of rate to substrate concentration, indicative of the involvement of two molecules of substrate in the reaction. The rate of hydrolysis was enhanced markedly by several p-nitrophenyl compounds including p-nitrophenyl glycosides, and also by Triton X-100 and chlorinated pesticides such as aldrin.
Wide Bandwidth Liquid Crystal Light Valve. (1979)

During this contract, we accomplished the following major tasks toward the development of a CCD liquid-crystal light valve. We have demonstrated a fully operational CCD LCLV with a contrast ratio of 50:1 and a spatial resolution of 12 lines across the device. An alternative chip dicing method has been developed that reduces degradation to the substrate by a factor of 100. In addition, a new CCD LCLV packaging technique has been developed that improves the light valve fabrication yield from 30% to 80%. (Author)
The human P2×1 receptor: molecular cloning, tissue distribution, and localization to chromosome 171 (1996)

A human urinary bladder cDNA library was screened with a rat P2x purinoceptor probe. A full-length cDNA was isolated, and like its rat homologue, the deduced protein consists of 399 amino acids (M(r) = 44980 Da), contains two hydrophobic, putative transmembrane, domains flanking a large presumed extracellular loop, and represents the P2x1 subtype of this multigene family (approximately 89% amino acid sequence identity to rat P2x1, but only 40-50% identity to rat P2x2-4). Expression of the P2x1 gene in human bladder was confirmed by Northern analysis, which demonstrated a major transcript of approximately 2.9 kb. Transcripts were also found in a variety of other tissues including adult peripheral leukocytes, pancreas, spleen, prostate, small intestine, colon, testis, and ovary, and in fetal liver. The gene encoding the human P2x1 receptor was localized to chromosome 17 by Southern analysis of DNAs isolated from a panel of somatic cell hybrids. The results support a role for P2x purinoceptors in the regulation of human bladder function.
Rational Delivery Strategies for the Design of Peptides with Enhanced Oral Delivery (1994)

One of the most significant biological barriers to delivery of peptides and peptide mimetics is the intestinal mucosa, which is a cell monolayer with tight intercellular junctions representing both an anatomical and an enzymatic barrier to the permeability of most polar molecules. In order to properly evaluate strategies for enhancing membrane permeability of peptides and peptide mimetics, our laboratory has developed an in vitro model of the intestinal mucosa, which consists of human adenocarcinoma cells (Caco-2) grown onto microporous membranes. This cell culture system, as well as an in situ intestinal perfusion model, has been employed in our laboratory to evaluate strategies for enhancing membrane permeability of peptides. The strategies that will be discussed in this article include: (1) designing conjugates of peptide mimetics targeted to endogenous transporter systems (e.g., bile acid) so as to enhance their intestinal permeability by a carrier-mediated pathway; and (2) optimizing the lipophilicity, hydrogen-bonding potential and conformation of peptide mimetics so as to enhance their intestinal permeability by passive diffusion.
Quantum transduction via frequency upconversion (Invited) (2007)

We describe a method for efficiently and coherently converting photons from one wavelength to another through the process of nonlinear upconversion. By using an intense 1064 nm escort laser pulse and a periodically poled lithium niobate (PPLN) crystal, we demonstrate upconversion efficiency of 99% and coherence of 95% for 1550 to 631 nm light at the single-photon level, thereby qualifying it for use in manipulation of photonic qubits. We then show how to create photons in arbitrary superpositions of different energy states, thereby enlarging the accessible Hilbert space for quantum information applications.
L-651,392, a potent leukotriene inhibitor, controls inflammatory process in Escherichia coli pyelonephritis (1994)

In this study, the relationship between leukotrienes, peritubular cell infiltration with polymorphonuclear cells (PMNs) and renal tubular damage was investigated in a rat model of acute ascending pyelonephritis. Infection was induced by the injection of 10(5) CFU of Escherichia coli into the bladder and occlusion of the left ureter for 24 h. Treatment of infected animals was started 24 h after the induction of pyelonephritis with either hydrocortisone (25 mg/kg of body weight per day), the leukotriene inhibitor L-651,392 (10 mg/kg/day), or the vehicle of L-651,392 and was maintained for 5 days. At the end of treatment, the animals were killed, serum was collected, and both kidneys were removed for colony counts and histopathology. Renal function was evaluated by the measurement of blood urea nitrogen levels and creatinine clearance. The numbers of PMNs and mononuclear cells (MNs) in the cortex and medulla were recorded for all groups on plastic sections done from the left kidney. Infection alone (vehicle of L-651,392) resulted in intensive interstitial infiltration and a severe tubular destruction in the cortex. Treatment with hydrocortisone did not prevent PMN migration and tissue damage. By contrast, treatment with L-651,392 resulted in a significant reduction in PMNs (P < 0.001 in comparisons with all other groups) and greater preservation of the tubular structure despite identical bacterial counts than in the group receiving hydrocortisone. We conclude that L-651,392 prevents inflammatory cells from reaching the site of infection and protects the kidney from tubular damage associated with inflammation during pyelonephritis. Inhibitors of leukotrienes should be further investigated for their potential benefit as adjuvants to antibiotherapy in the treatment of pyelonephritis.
Fabrication of Graphene–Polymer Nanocomposites With Higher‐Order Three‐Dimensional Architectures (2009)

The use of aqueous dispersions of polystyrene sulfonate-stabilized graphene sheets for the fabrication of nanocomposites with higher-order 3D architectures is demonstrated using two examples of template-directed assembly. Macroscopic sponge-like polymer–graphene scaffolds are readily produced by directional freeze casting, while hollow graphene microspheres are prepared by electrostatically induced assembly on positively charged polymer beads.
Challenges in the clinical development of PI3K inhibitors (2013)

The PI3K/Akt/mTOR pathway is one of the most frequently dysregulated signaling pathways in cancer and an important target for drug development. PI3K signaling plays a fundamental role in tumorigenesis, governing cell proliferation, survival, motility, and angiogenesis. Activation of the pathway is frequently observed in a variety of tumor types and can occur through several mechanisms. These mechanisms include (but are not limited to) upregulated signaling via the aberrant activation of receptors upstream of PI3K, amplification or gain-of-function mutations in the PIK3CA gene encoding the p110α catalytic subunit of PI3K, and inactivation of PTEN through mutation, deletion, or epigenetic silencing. PI3K pathway activation may occur as part of primary tumorigenesis, or as an adaptive response (via molecular alterations or increased phosphorylation of pathway components) that may lead to resistance to anticancer therapies. A range of PI3K inhibitors are being investigated for the treatment of different types of cancer; broad clinical development plans require a flexible yet well-structured approach to clinical trial design.
Optimization of peptide synthesis on polyethylene rods. (1994)

Multipin solid-phase peptide synthesis is widely used for epitope mapping of monoclonal and polyclonal antibodies. However, neither the chemical yield nor the homogeneity of products currently match those of solid-phase synthesis of peptides on resins. In order to improve synthesis parameters, we have repeated the standard procedure and introduced modifications during synthesis of model heptapeptides and peptides from the sequence of rhodopsin and other proteins. Good incorporation of amino acids using the multipin peptide synthesis system can now be obtained in less synthesis time and with less costly reagents.
BodyMAC: Energy efficient TDMA-based MAC protocol for Wireless Body Area Networks (2009)

Wireless body area networks (WBANs) enable placement of tiny biomedical sensors on or inside the human body to monitor vital body signs. The IEEE 802.15.6 task group is developing a standard to optimize WBAN performance by defining the physical layer (PHY) and media access control (MAC) layer specifications. In this paper an energy efficient MAC protocol (BodyMAC) is proposed. It uses flexible bandwidth allocation to improve node energy efficiency by reducing the possibility of packet collisions and by reducing radio transmission times, idle listening and control packets overhead. BodyMAC is based on a Downlink and Uplink scheme in which the Contention Free Part in the Uplink subframe is completely collision free. Three types of bandwidth allocation mechanisms allow for flexible and efficient data and control communications. An efficient Sleep Mode is introduced to reduce the idle listening duration, especially for low duty cycle nodes in the network. Simulation results show superior performance of BodyMAC compared to that of the IEEE 802.15.4 MAC.
Sol−Gel Column Technology for Single-Step Deactivation, Coating, and Stationary-Phase Immobilization in High-Resolution Capillary Gas Chromatography (1997)

A sol−gel chemistry-based novel approach to column technology for high-resolution capillary gas chromatography is described that effectively combines surface treatment, deactivation, coating, and stationary phase immobilization into a single step. In the conventional approach, these operations are carried out in separate steps that make column fabrication a time-consuming job. In the new approach, a cleaned fused silica capillary is filled with a sol solution of appropriate composition, and sol−gel reactions are allowed to go on inside the capillary for a controlled period, typically 15−60 min. A wall-bonded coating results due to condensation of the surface silanol groups with the sol−gel network evolving in their vicinity. Because of the direct chemical bonding to fused silica substrates, sol−gel coatings possess significantly higher thermal stability than conventional coatings. This is especially important for thick and/or polar stationary phase coatings that are difficult to immobilize. Scanning electron microscopic studies revealed that sol−gel coatings were characterized by roughened surfaces, providing a number of chromatographic advantages, including higher surface area and faster mass transfer kinetics. Sol−gel column technology does not require any free radical cross-linking procedures for stationary phase immobilization and easily avoids any undesirable changes in the stationary phase properties that might be associated with the cross-linking reactions used in conventional technology. Sol−gel-coated poly(dimethylsiloxane) and Ucon columns provided efficient separations for analytes from a wide polarity range, including free fatty acids, phenolic compounds, amines, aldehydes, ketones, alcohols, and diols that are prone to peak tailing due to adsorptive interactions with the column walls. This suggests excellent quality of column deactivation. The new technology provided at least a 10-fold reduction in column preparation time. The sol−gel approach is universal in nature and can be effectively applied to a wide range of microcolumn separation techniques.
LC/NMR in Natural Products Chemistry (1998)

Efficient detection and rapid characterisation of natural products play an important role for their study in complex biological matrices such as crude plant extracts. Their preliminary identification at the earliest stage of separation is a strategic element for guiding selective isolation procedures. Hyphenated techniques such as high performance liquid chromatography (HPLC) coupled to UV and mass spectrometry (LC/UV/MS) have proved to be extremely useful in combination with biological screening for a rapid survey of natural products. However, these coupled techniques do not allow a full on-line identification, except for some well-known natural products, and complementary on-line spectroscopic information is needed. Thus, HPLC coupled to nuclear magnetic resonance (LC/NMR) represents a potentially interesting complementary technique to LC/UV/MS for detailed on-line structural analysis. Indeed recent progress in NMR technology has given a new impulse to LC/NMR which is now emerging as a powerful analytical tool. The development of efficient solvent suppression techniques enables the measurement of high quality LC/&lt;sup&gt;1&lt;/sup&gt;H-NMR spectra, both on-flow and stop-flow, with reversed-phase HPLC conditions. Non-deuterated solvents such as MeOH or MeCN can be used, while water is replaced by D&lt;sub&gt;2&lt;/sub&gt;O. In this review, a summary of the basic principles and modes of operation of LC/NMR are briefly described. Selected examples of LC/NMR analyses of natural products in crude p lant extract o r in enriched fractions are presented. They include different ways of using this technique. An overview of the relatively scarce applications with natural products is given. The potential and the limitations of LC/NMR in conjunction with LC/UV/MS for the on-line analysis of plant metabolites are discussed.
Growth Factors Can Influence Cell Growth and Survival through Effects on Glucose Metabolism (2001)

Cells from multicellular organisms are dependent upon exogenous signals for survival, growth, and proliferation. The relationship among these three processes was examined using an interleukin-3 (IL-3)-dependent cell line. No fixed dose of IL-3 determined the threshold below which cells underwent apoptosis. Instead, increasing growth factor concentrations resulted in progressive shortening of the G(1) phase of the cell cycle and more rapid proliferative expansion. Increased growth factor concentrations also resulted in proportional increases in glycolytic rates. Paradoxically, cells growing in high concentrations of growth factor had an increased susceptibility to cell death upon growth factor withdrawal. This susceptibility correlated with the magnitude of the change in the glycolytic rate following growth factor withdrawal. To investigate whether changes in the availability of glycolytic products influence mitochondrion-initiated apoptosis, we artificially limited glycolysis by manipulating the glucose levels in the medium. Like growth factor withdrawal, glucose limitation resulted in Bax translocation, a decrease in mitochondrial membrane potential, and cytochrome c redistribution to the cytosol. In contrast, increasing cell autonomous glucose uptake by overexpression of Glut1 significantly delayed apoptosis following growth factor withdrawal. These data suggest that a primary function of growth factors is to regulate glucose uptake and metabolism and thus maintain mitochondrial homeostasis and enable anabolic pathways required for cell growth. Consistent with this hypothesis, expression of the three genes involved in glucose uptake and glycolytic commitment, those for Glut1, hexokinase 2, and phosphofructokinase 1, was found to rapidly decline to nearly undetectable levels following growth factor withdrawal.
Dynamics and Energetics of the Explosive Vaporization of Fog Droplets by a 106-μm Laser Pulse (1973)

The explosive vaporization of individual water droplets (5 microm to 25 microm radius) by a 10.6-microm laser pulse has been observed with a high speed schlieren photography system. The hot vapor and the shock wave produced by the explosive vaporization can be clearly seen in the schlieren photographs. The expansion rate of the heated air mass has been measured. Factors affecting the shape of the volume of heated air are discussed, and the energy balance of the process is considered.
Transplantation of Monocyte CC-Chemokine Receptor 2–Deficient Bone Marrow Into ApoE3–Leiden Mice Inhibits Atherogenesis (2003)

These results provide direct evidence that CCR2 expressed by leukocytes plays a critical role in the initiation of early atherosclerosis and that pharmacological intervention in CCR2 function represents an attractive target to inhibit atherogenesis.
Processing of engulfed apoptotic bodies yields T cell epitopes (1997)

Programmed death via apoptosis is the metazoan physiologic mode of cell death. Apoptotic cells are recognized by scavenger phagocytes via a number of membrane receptors and engulfed. Thereafter, little is known of their fate, or that of phagocytes. Here, we have traced apoptotic cells upon their engulfment by macrophages. After 3 h, apoptotic cells were contained in discrete well-defined vacuoles. Upon overnight chase, several small vesicles, possibly originating from the fragmentation of original vacuoles, were evident all over the macrophage body. Furthermore, Ags were diffused in the cytosol of some cells, which raises the possibility that epitopes from engulfed apoptotic cells may associate with macrophage MHC class I molecules and be recognized by T lymphocytes. Indeed, Ag-specific CTLs recognize and specifically lyse syngeneic macrophages upon phagocytosis of MHC class I-positive or -negative apoptotic cells, provided that they contain the relevant Ags. Synthesis and membrane expression of class I molecules by macrophages, together with functional transporters associated with Ag presentation, were necessary for recognition and lysis. The indirect presentation of epitopes from engulfed apoptotic cells by scavenger Ag-presenting phagocytes may, in the absence of "danger" signals, have implications for the establishment of central and peripheral self-tolerance.
Calichemicins, a novel family of antitumor antibiotics. 1. Chemistry and partial structure of calichemicin .gamma.1I (1987)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCalichemicins, a novel family of antitumor antibiotics. 1. Chemistry and partial structure of calichemicin .gamma.1IMay D. Lee, Theresa S. Dunne, Marshall M. Siegel, Conway C. Chang, George O. Morton, and Donald B. BordersCite this: J. Am. Chem. Soc. 1987, 109, 11, 3464–3466Publication Date (Print):May 1, 1987Publication History Published online1 May 2002Published inissue 1 May 1987https://doi.org/10.1021/ja00245a050RIGHTS & PERMISSIONSArticle Views982Altmetric-Citations353LEARN 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 (398 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
A comparison of high level synthesis and register transfer level design techniques for custom computing machines (2002)

The most expensive component in the process of building a custom computing machine is the time consuming and highly qualified work of hardware designers. This hinders the wide proliferation of CCMs and pushes this innovative technology into a niche market of research applications. A potential solution to the problem is behavioural or high level synthesis (HLS) which promises the compilation of algorithms into hardware. The experiment reported in this paper was aimed at the evaluation of general purpose HLS tools in building CCMs. We focused on identifying areas where the synthesis methods and tools should be improved in order to cope with CCM's specific design problems. The design case, a specialised computer for the simulation of the sintering process, has been carefully chosen to exhibit the problems that are likely to be encountered in advanced designs for CCMs. Our experiment shows that the HLS tools, when supplied with an appropriate input description, are capable of producing a design not too different from RTL level manual design. HLS needs to be improved, especially regarding loop unwinding, pipelining, and the synthesis of suitable memory configurations. However, many of the required techniques are already available from the field of parallel compilation. The conclusion is that improved HLS tools will bring the performance of compiled CCMs very close to that of manual designs. This can put the high performance of CCM technology at the fingertips of computer programmers without extensive hardware expertise.
Efficient photovoltaic and electroluminescent perovskite devices (2014)

Planar diode structures employing hybrid organic-inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method.
The L-Arginine-Nitric Oxide Pathway (1993)

The discovery that mammalian cells generate nitric oxide, a gas previously considered to be merely an atmospheric pollutant, is providing important information about many biologic processes. Nitric oxide is synthesized from the amino acid L-arginine by a family of enzymes, the nitric oxide synthases, through a hitherto unrecognized metabolic route -- namely, the L-arginine-nitric oxide pathway18.The synthesis of nitric oxide by vascular endothelium is responsible for the vasodilator tone that is essential for the regulation of blood pressure. In the central nervous system nitric oxide is a neurotransmitter that underpins several functions, including the formation of memory. . . .