gebhart/patrepeval huggingface dataset:
Demonstration, by somatic cell genetics, of coordinate regulation of genes for two enzymes of purine synthesis assigned to human chromosome 21. (1981)

A method for determining coordinate genetic regulation is proposed for mammalian cells. The method involves (i) isolation of a set of mutants defective in the relevant pathway; (ii) complementation analysis of these mutants to determine dominance and to categorize the mutants into various different complementation groups; (iii) determination of the biochemical blocks in the mutants; (iv) identification of individual mutants that fail to complement the members of at least two distinct complementation groups that complement each other, such mutants being said to show coordinate regulation of the affected functions; (v) biochemical and reversion analysis of the relevant cell types to confirm the basis for the observed coordinate regulation; (vi) assignment of the individual genes to particular human chromosomes; (vii) mapping of the genes to determine contiguity on the genome; and (viii) examination of the structure of the relevant gene products. This method has allowed the demonstration of coordinate regulation between the gene coding for phosphoribosylglycineamide synthetase [5-phosphoribosylamine:glycine ligase (ADP-forming), EC 6.3.4.13], defective in our Ade-C mutants, and the gene coding for phoshoribosylaminoimidazole synthetase [5'-phosphoribosylformylglycinamidine cyclo-ligase (ADP-forming), EC 6.3.3.1], defective in our Ade-G mutants. Moreover, both genes can be assigned to human chromosome 21. Because at least two genes for purine biosynthesis have now been assigned to chromosome 21, and because patients with trisomy 21 (Down syndrome) show increased levels of serum purines, it may be that cells of these patients overproduce purines and that this overproduction may be relevant to the pathology of the syndrome.
Hydroxyurea increases the phosphorylation of 3′‐fluorothymidine and 3′‐azidothymidine in CEM cells (1989)

The triphosphates of the nucleoside analogues 3'-azidothymidine and 3'-fluorothymidine inhibit reverse transcriptase and are of therapeutic interest for the treatment of retrovirus infections. At equimolar concentrations 3'-fluorothymidine was more effectively transformed to the triphosphate by human CEM cells than azidothymidine which mainly accumulates as the monophosphate. Hydroxyurea, a drug that inhibits de novo synthesis of deoxyribonucleotides, considerably increased the ability of cells to phosphorylate both analogues. Addition of as little as 50 microM hydroxyurea decreased the amount of dideoxynucleoside required to attain a given intracellular concentration of its triphosphate by an order of magnitude. Hydroxyurea is known to shift the balance of substrate cycles between natural deoxynucleosides and their 5'-phosphates in the direction of synthesis and thereby to increase the import and intracellular phosphorylation of the nucleoside. The present results demonstrate a similar effect for the two analogues and raise the possibility of using this effect in therapy.
Calculation of free energy through successive umbrella sampling (2004)

We consider an implementation of umbrella sampling in which the pertinent range of states is subdivided into small windows that are sampled consecutively and linked together. This allows us to simulate without a weight function or to extrapolate the results to the neighboring window in order to estimate a weight function. Additionally, we present a detailed error analysis in which we demonstrate that the error in umbrella sampling is controlled and, in the absence of sampling difficulties, independent of the window sizes. In this case, the efficiency of our implementation is comparable to a multicanonical simulation with a very good weight function, which in our scheme does not need to be known ahead of time. The analysis also allows us to detect sampling difficulties such as correlations between adjacent windows and provides a test of equilibration. We exemplify the scheme by simulating the liquid-vapor coexistence in a Lennard-Jones system.
The Equilibrium Theory of Inhomogeneous Polymers (2005)

Abstract This book provides an introduction to the field-theoretic methods and computer simulation techniques used in the design of structured polymeric fluids for a wide variety of applications. By such methods, the principles that dictate equilibrium self-assembly in systems ranging from block and graft copolymers, to polyelectrolytes, liquid crystalline polymers, and polymer nanocomposites can be established. Building on an introductory discussion of single-polymer statistical mechanics, the book provides a detailed treatment of analytical and numerical techniques for addressing the statistical properties of polymers subjected to spatially-varying potential fields. This problem is shown to be central to the field-theoretic description of interacting polymeric fluids, and models for a number of important polymer systems are elaborated. Self-consistent field theory is treated in detail, which is a collection of analytical and numerical techniques for obtaining solutions of polymer field theory models in the mean-field approximation. The book concludes with a discussion of analytical methods for going beyond the mean-field approximation and an introduction to the exciting new field of field-theoretic polymer simulations — the direct numerical simulation of polymer field theory models.
Expression of an activated erythropoietin or a colony-stimulating factor 1 receptor by pluripotent progenitors enhances colony formation but does not induce differentiation. (1994)

Whether the presence of specific receptors on the surface of developing cells is the cause or consequence of lineage restriction is not known. If activation of specific receptors is the driving event in differentiation, the premature expression of specific receptors would promote differentiation along that pathway. In this study pluripotent progenitors, obtained from blast cell colonies (pooled or individual) of 5-fluorouracil-treated mice, were infected with retroviral vectors containing either an activated receptor for erythropoietin (EPO), an erythroid progenitor growth factor, or the receptor for colony-stimulating factor 1 (CSF-1), a macrophage growth factor. These receptors exhibit expression patterns restricted to committed progenitors. The developmental potential of infected pluripotent progenitors was not changed, although they expressed the exogenous genes, suggesting that in these cells activation of lineage-specific receptors does not induce differentiation. Acquisition of a constitutively activated EPO receptor allowed erythroid development in mixed colonies in the absence of EPO, as expected. Infection of progenitors with a virus containing the CSF-1 receptor promoted the development of granulocyte/macrophage (GM) colonies but did not alter the differentiation potential of either colony-forming unit (CFU)-GM or CFU-mix.
Data Products, Quality and Validation of the DLR Earth Sensing Imaging Spectrometer (DESIS) (2019)

Imaging spectrometry from aerial or spaceborne platforms, also known as hyperspectral remote sensing, provides dense sampled and fine structured spectral information for each image pixel, allowing the user to identify and characterize Earth surface materials such as minerals in rocks and soils, vegetation types and stress indicators, and water constituents. The recently launched DLR Earth Sensing Imaging Spectrometer (DESIS) installed on the International Space Station (ISS) closes the long-term gap of sparsely available spaceborne imaging spectrometry data and will be part of the upcoming fleet of such new instruments in orbit. DESIS measures in the spectral range from 400 and 1000 nm with a spectral sampling distance of 2.55 nm and a Full Width Half Maximum (FWHM) of about 3.5 nm. The ground sample distance is 30 m with 1024 pixels across track. In this article, a detailed review is given on the applicability of DESIS data based on the specifics of the instrument, the characteristics of the ISS orbit, and the methods applied to generate products. The various DESIS data products available for users are described with the focus on specific processing steps. The results of the data quality and product validation studies show that top-of-atmosphere radiance, geometrically corrected, and bottom-of-atmosphere reflectance products meet the mission requirements. The limitations of the DESIS data products are also subject to a critical examination.
Gli strumenti di reference e i repertori delle risorse (2017)

Gli strumenti di reference e i repertori delle risorse.
Creativity, Culture, Knowledge and the City (2004)

'Practical men, who believe themselves to be quite exempt from any intellectual influences, are usually the slaves of some defunct economist', John Maynard Keynes once memorably wrote. 'Madmen in authority, who hear voices in the air', he argued, 'are distilling their frenzy from some academic scribbler of a few years back'. He might have reached exactly that conclusion about the creative city except that here the scribblers are on frenetic whistle-stop lecture tours. It now seems that every city in the developed world, and not a few in the developing world, wants to acquire the secret of instant creativity Elder or at least middle-aged statesmen, who really should know better, goad them into this competition. It's the only game in town any town. But, as the articles in this collection have shown, it might be worthwhile first to take a deep breath for reflection. Much of the current enthusiasm about creative cities
SiC device edge termination using finite area argon implantation (1997)

In this paper, the results obtained with limited area amorphization by argon ion-implantation at the periphery of 6H-SiC Schottky barrier diodes are reported. It is demonstrated that only 50 /spl mu/m of implant region is required at the periphery to obtain ideal plane parallel breakdown voltages. The leakage current at small reverse bias voltages was found to be directly proportional to the implant area.
Probing the Active Site of Cytochrome P450 2B1:  Metabolism of 7-Alkoxycoumarins by the Wild Type and Five Site-Directed Mutants (1998)

A series of 7-alkoxycoumarins (chain length of 1-7 carbon atoms) was utilized as active site probes of purified Escherichia coli-expressed cytochrome P450 2B1 wild type and five site-directed mutants (I114V, F206L, V363A, V363L, and G478S). The production of 7-hydroxycoumarin, the O-dealkylation product, by the wild-type enzyme exhibited a rank order of C2 > C4 > C3 > C1 > C5 > C6 = C7. The pattern observed for the P450 I114V mutant was similar to that of the wild-type enzyme, whereas with F206L and G478S mutants, the rate of O-dealkylation was low with all the compounds. In contrast, with V363A, the highest rate of product formation was observed with 7-butoxycoumarin. The V363L mutant preferentially catalyzed the O-dealkylation of 7-methoxy- and 7-ethoxycoumarin, and a further increase in the length of the alkyl chain led to a marked decrease in product formation. The stoichiometry of 7-butoxycoumarin oxidation by V363L suggested that products other than 7-hydroxycoumarin were also formed. HPLC and GC-EIMS analyses revealed that P450 2B1 V363L produced 7-(3-hydroxybutoxy)coumarin and 7-(4-hydroxybutoxy)coumarin as major oxidation products, while the V363A mutant mainly catalyzed the O-dealkylation of 7-butoxycoumarin. Docking of alkoxycoumarins into the active site of a P450 2B1 homology model confirmed the importance of the studied residues in substrate dealkylation and explained the formation of novel 7-butoxycoumarin products by the V363L mutant.
cDNA cloning, expression during development, and genome mapping of PSY2, a second tomato gene encoding phytoene synthase. (1993)

The enzyme phytoene synthase (Psy) catalyzes the formation of phytoene, an intermediate in the carotenoid biosynthesis pathway. Expression of a previously described gene (PSY1) is induced by fruit ripening in tomato (Lycopersicon esculentum). We describe here the cloning of a partial cDNA for PSY2, a gene related to PSY1. A plasmid containing the PSY2 coding region under control of a bacterial promoter complements a Rhodobacter capsulatus phytoene synthase mutant, indicating that this gene has the capacity to encode an active enzyme. We used reverse transcriptase-polymerase chain reaction followed by digestion with a restriction enzyme to determine that both PSY1 and PSY2 are expressed during tomato development. PSY1 transcripts predominate in seedlings and in late stages of fruit ripening, whereas PSY2 transcripts are relatively more abundant in mature leaves. Both genes are expressed under photooxidative conditions induced by treatment with the carotenoid biosynthesis inhibitor Norflurazon. We used polymerase chain reaction-based restriction fragment length polymorphisms and alien addition lines to map PSY2 to chromosome 2. We conclude that PSY2 is a second tomato gene encoding phytoene synthase.
Surface-micromachined thermal conductivity detectors for gas sensing (2012)

This paper presents the design, analysis, fabrication and a special approach for readout of surface-micromachined thermal conductivity (TCD) gas sensors. IC-compatible surface-micromachining MEMS technology has been applied for the fabrication of high-sensitivity thermal sensors. The devices have been fabricated on thin SiN bridges with thermoelectric detectors as temperature sensors and poly-silicon resistors as heaters. A general thermal analysis of planar MEMS structures is included for calculating both the static and dynamic response of micro-TCD's. The analysis demonstrates that the performance of surface-micromachined devices can be superior to that of the more conventional bulk-micromachined devices. Methods for DC and AC readout of the device are discussed and have been implemented. The sensitivity for hydrogen in air is about 60μV per % H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> at 1mW heater dissipation. Measurements on pure gases and gas mixtures have indicated a high sensitivity of 4.4 μV per Wm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and a typical stability of 0.05 μV when using AC modulation.
Singlet fission of hot excitons in <i>π</i> -conjugated polymers (2015)

We used steady-state photoinduced absorption (PA), excitation dependence (EXPA(ω)) spectrum of the triplet exciton PA band, and its magneto-PA (MPA(B)) response to investigate singlet fission (SF) of hot excitons into two separated triplet excitons, in two luminescent and non-luminescent π-conjugated polymers. From the high energy step in the triplet EXPA(ω) spectrum of the luminescent polymer poly(dioctyloxy)phenylenevinylene (DOO-PPV) films, we identified a hot-exciton SF (HE-SF) process having threshold energy at E≈2E(T) (=2.8 eV, where ET is the energy of the lowest lying triplet exciton), which is about 0.8 eV above the lowest singlet exciton energy. The HE-SF process was confirmed by the triplet MPA(B) response for excitation at E>2E(T), which shows typical SF response. This process is missing in DOO-PPV solution, showing that it is predominantly interchain in nature. By contrast, the triplet EXPA(ω) spectrum in the non-luminescent polymer polydiacetylene (PDA) is flat with an onset at E=E(g) (≈2.25 eV). From this, we infer that intrachain SF that involves a triplet-triplet pair state, also known as the 'dark' 2A(g) exciton, dominates the triplet photogeneration in PDA polymer as E(g)>2E(T). The intrachain SF process was also identified from the MPA(B) response of the triplet PA band in PDA. Our work shows that the SF process in π-conjugated polymers is a much more general process than thought previously.
Modulation by palmitoyl-carnitine of calcium activated, phospholipid-dependent protein kinase activity and inhibition of melanoma cell growth (1988)

Phospholipid-sensitive, Ca++-dependent protein kinase activity was investigated in the cytosol of melanoma cells. A protein kinase system was partially purified, and enzyme activity was found to be modulated by palmitoyl-carnitine. In order to link the actions of palmitoyl-carnitine on phospholipid-sensitive protein kinase activity and the already reported role of protein kinase C in cell division, we studied the action of palmitoyl-carnitine on melanoma cell growth by measuring colony forming ability in a soft agar culture system. Palmitoyl-carnitine was found to inhibit cell growth in a dose-dependent manner. These findings suggest that palmitoyl-carnitine (or long-chain acylcarnitine), a naturally occurring metabolite, may play a key role in the onset of cell division. We suggest that the action of palmitoyl-carnitine on phospholipid-dependent protein kinase activity is in part related to the molecular events linking protein kinase C activity and the ionic events in the initiation of cell growth.
A Bandwidth Aggregation-Aware QoS Negotiation Mechanism for Next-Generation Wireless Networks (2007)

The transmission of high quality video requires high bandwidth. Ensuring constantly high bandwidth in wireless environments is a challenging task given constraints in the current wireless network resources. Current mobile computers are equipped with multiples wireless interfaces that can be used to improve the video quality by aggregating the bandwidth of these interfaces. Such Bandwidth Aggregation (BAG) approach involves multiple paths in communication and gives rise to a number of issues related to the management of the Service Level Agreement (SLA) and packet reordering. To guarantee an efficient and fair management of SLA, this paper presents a bandwidth aggregation-aware QoS negotiation mechanism that enables users to dynamically negotiate their desired service levels and to reach them through the use of bandwidth aggregation. This operation is performed while ensuring a fair use of the network resources among all competing users. To cope with packet reordering, a new scheduling strategy is presented. The performance evaluation of the proposed bandwidth aggregation-aware QoS negotiation scheme and the proposed scheduling algorithm are conducted via simulations and the results are discussed.
Evaluation of forecasting techniques for short-term demand of air transportation (1995)

May 1995
Synthesis and hypolipidemic and antidiabetogenic activities of .beta.,.beta.,.beta.',.beta.'-tetrasubstituted, long-chain dioic acids (1989)

beta,beta,beta',beta'-Tetrasubstituted, long-chain dioic acids of the general formula HOOC-C(XY)-C(R2)-Q-C-(R2)-C(XY)-COOH have been synthesized and evaluated as hypotriglyceridemic-hypocholesterolemic agents in rats and as antidiabetogenic agents in ob/ob diabetic mice. The free carboxyl function of analogues of the series was mandatory for their hypolipidemic-antidiabetogenic effect while nonhydrolyzable diesters were inactive. Other structure-activity relationships were determined as a function of the overall chain length (C12-C22), alpha,alpha'-substitutions (X, Y = H, F, Cl, Br, OH, CN), beta, beta'-substitutions (R = CH3, C6H5), and core substitutions [Q = (CH2)10, (CH2)4CH = CH(CH2)4, 1,4-C6H10[(CH2)3]2, 1,4-C6H4[(CH2)3]2, 1,4-C6H4(CH = CHCH2)2, CH2(OCH2CH2)3OCH2)]. The most effective hypolipidemic-antidiabetogenic members of the series were alpha,alpha'-nonsubstituted, beta,beta'-methyl-substituted analogues of 14-18-carbon chains having either a saturated aliphatic core or a 1,4-bis(propenyl)benzene core in the cis/trans configuration. The hypotriglyceridemic rather than the hypocholesterolemic capacity of members of the series was found to correlate with their respective capacities as liver peroxisomal proliferators in rats.
Completion and operational testing of the Adams' permanent magnet electric D.C. motor-generator (2015)

This paper focuses on description of the operation principle inherent to the Adams' electric motor-generator fitted with permanent magnets made of rare earth (NdFeB). There is a certain part dedicated to distribution of the magnetic field within the magnetic circuit of rotor and stator monitoring by means of the Ansys Workbench software. The Adams' motor generator is basically assembled with slight deviations from the original patent with respect to the stator magnetic circuit design. The resultant speed-torque characteristics obtained by measurement and the input power values have been processed to determine the machine's efficiency.
Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate (2017)

Hydraulic fracture initiation and near wellbore propagation is governed by complex failure mechanisms, especially in cased perforated wellbores. Various parameters affect such mechanisms, including fracturing fluid viscosity and injection rate. In this study, three different fracturing fluids with viscosities ranging from 20 to 600 Pa.s were used to investigate the effects of varying fracturing fluid viscosities and fluid injection rates on the fracturing mechanisms. Hydraulic fracturing tests were conducted in cased perforated boreholes made in tight 150 mm synthetic cubic samples. A true tri-axial stress cell was used to simulate real far field stress conditions. In addition, dimensional analyses were performed to correspond the results of lab experiments to field-scale operations. The results indicated that by increasing the fracturing fluid viscosity and injection rate, the fracturing energy increased, and consequently, higher fracturing pressures were observed. However, when the fracturing energy was transferred to a borehole at a faster rate, the fracture initiation angle also increased. This resulted in more curved fracture planes. Accordingly, a new parameter, called fracturing power, was introduced to relate fracture geometry to fluid viscosity and injection rate. Furthermore, it was observed that the presence of casing in the wellbore impacted the stress distribution around the casing in such a way that the fracture propagation deviated from the wellbore vicinity.
A small-animal imaging system based on silicon strip detectors (2003)

We have investigated the design of a high-resolution nuclear medicine system for in vivo small-animal imaging. The system utilizes a multiple-pinhole collimator in conjunction with silicon double-sided strip detectors (DSSDs) in a synthetic collimator configuration. It is designed for detection of the low-energy photons (27-35 keV) from the decay of /sup 125/I or /sup 123/I. We discuss elements of the system and present simulations conducted thus far.