gebhart/patrepeval huggingface dataset:
Two phase flow distribution in parallel flow heat exchangers -- experimentally verified model (2012)

Maldistribution of refrigerant is a problem in parallel microchannel heat exchangers that lowers their potential effectiveness, especially when controlled by superheat. This paper describes modeling and numerical simulation of two phase mass flow distribution in a microchannel evaporator, on the basis of the pseudo 2-D finite volume method. Emphasis is placed on refrigerant-side heat transfer and pressure drop characteristics. The global flow distribution is based on the mechanistic fact that the pressure drop along each flow path containing an individual microchannel tube must be the same. Besides the primary pressure drop across the microchannel tube, other pressure drops are also considered and modeled. These include the frictional pressure loss along the inlet/outlet headers, as well as contraction and expansion loss associated with fluid entering and leaving the tube. Mass flow rate and quality in each microchannel tube, overall pressure drop and evaporator surface temperatures are calculated and then compared to data taken from the experimental facility.\nThis maldistribution model simulates refrigerant distribution in a microchannel evaporator for two cases. In the first case, the flash gas bypass system, flash gas from the expansion valve is separated and only single phase liquid is supplied into the evaporator. The second case is a conventional direct expansion system where refrigerant enters the evaporator in a two-phase state. For the second case, a quality distribution profile along the inlet header is proposed to simulate the liquid-vapor distribution in the microchannel tubes. The second case is the same as the first case, with a quality distribution profile added. \nThe maldistribution model is compared to a uniform distribution model, a common assumption made in open literature where all microchannel tubes receive identical flow rate. Comparing the maldistribution and uniform distribution models to experimental data, results indicate that the uniform distribution model predicts a higher superheat than the maldistribution model in every case. In order to compare cooling capacity prediction, the mass flow rate in the uniform distribution model was then increased until the exit superheat matched the superheat of the maldistribution model. For every case, the cooling capacity is over predicted by the uniform distribution model by an average of 34%. If an evaporator model is to be used as a design tool, it becomes necessary to use the mass flow distribution model to accurately predict both superheat and cooling capacity accurately.
Field-Excited Electron Emission from ( 1-y)Pb(Mg<sub> 1/3</sub>Nb<sub> 2/3</sub>)O<sub> 3</sub>-yPbTiO<sub> 3</sub> Ceramic (1996)

Electron emission from a (1- y )Pb(Mg 1/3 Nb 2/3 )O 3 - y PbTiO 3 (PMN-PT) ferroelectric ceramic plate has been observed in vacuum by applying a pair of bipolar pulse voltages. The emission is observed even at temperatures above the Curie temperature, as is that of a lead-zirconate-titanate (PZT) ceramic plate. The amount of emitted charge from PMN-PT ceramic is about 5 times larger than that from PZT ceramic, and increases with increasing pulse width. Furthermore, the temperature dependence of the emitted charge suggests that the amount of emitted charge depends strongly on the dielectric constant of the sample. It is considered that the emission is induced by abrupt change of dielectric flux as well as the polarization reversal.
Arginine Metabolism in Developing Soybean Cotyledons (1989)

Tracerkinetic experiments were performed using l-[guanidino-(14)C]arginine, l-[U-(14)C]arginine, l-[ureido-(14)C]citrulline, and l-[1-(14)C]ornithine to investigate arginine utilization in developing cotyledons of Glycine max (L.) Merrill. Excised cotyledons were injected with carrier-free (14)C compounds and incubated in sealed vials containing a CO(2) trap. The free and protein amino acids were analyzed using high performance liquid chromatography and arginine-specific enzyme-linked assays. After 4 hours, 75% and 90% of the (14)C metabolized from [guanidino-(14)C]arginine and [U-(14)C]arginine, respectively, was in protein arginine. The net protein arginine accumulation rate, calculated from the depletion of nitrogenous solutes in the cotyledon during incubation, was 17 nanomoles per cotyledon per hour. The data indicated that arginine was also catabolized by the arginase-urease reactions at a rate of 5.5 nanomoles per cotyledon per hour. Between 2 and 4 hours (14)CO(2) was also evolved from carbons other than C-6 of arginine at a rate of 11.0 nanomoles per cotyledon per hour. It is suggested that this extra (14)CO(2) was evolved during the catabolism of ornithine-derived glutamate; (14)C-ornithine was a product of the arginase reaction. A model for the estimated fluxes associated with arginine utilization in developing soybean cotyledons is presented.The maximum specific radioactivity ratios between arginine in newly synthesized protein and total free arginine in the (14)C-citrulline and (14)C-ornithine experiments indicated that only 3% of the free arginine was in the protein precursor pool, and that argininosuccinate and citrulline were present in multiple pools.
Aspergillus ficuum phytase activity is inhibited by cereal grain components (2017)

In the current study, we report for the first time that grain components of barley, rice, wheat and maize can inhibit the activity of Aspergillus ficuum phytase. The phytase inhibition is dose dependent and varies significantly between cereal species, between cultivars of barley and cultivars of wheat and between Fusarium graminearum infected and non-infected wheat grains. The highest endpoint level of phytase activity inhibition was 90%, observed with grain protein extracts (GPE) from F. graminearum infected wheat. Wheat GPE from grains infected with F. graminearum inhibits phytase activity significantly more than GPE from non-infected grains. For four barley cultivars studied, the IC50 value ranged from 0.978 ± 0.271 to 3.616 ± 0.087 mg×ml-1. For two non-infected wheat cultivars investigated, the IC50 values were varying from 2.478 ± 0.114 to 3.038 ± 0.097 mg×ml-1. The maize and rice cultivars tested gaveIC50 values on 0.983 ± 0.205 and 1.972 ± 0.019 mg×ml-1, respectively. After purifying the inhibitor from barley grains via Superdex G200, an approximately 30-35 kDa protein was identified. No clear trend for the mechanism of inhibition could be identified via Michaelis-Menten kinetics and Lineweaver-Burk plots. However, testing of the purified phytase inhibitor together with the A. ficuum phytase and the specific protease inhibitors pepstatin A, E64, EDTA and PMSF revealed that pepstatin A repealed the phytase inhibition. This indicates that the observed inhibition of A. ficuum phytase by cereal grain extracts is caused by protease activity of the aspartic proteinase type.
Microtubule dysfunction by posttranslational nitrotyrosination of α-tubulin: A nitric oxide-dependent mechanism of cellular injury (1999)

NO2Tyr (3-Nitrotyrosine) is a modified amino acid that is formed by nitric oxide-derived species and has been implicated in the pathology of diverse human diseases. Nitration of active-site tyrosine residues is known to compromise protein structure and function. Although free NO2Tyr is produced in abundant concentrations under pathological conditions, its capacity to alter protein structure and function at the translational or posttranslational level is unknown. Here, we report that free NO2Tyr is transported into mammalian cells and selectively incorporated into the extreme carboxyl terminus of alpha-tubulin via a posttranslational mechanism catalyzed by the enzyme tubulin-tyrosine ligase. In contrast to the enzymatically regulated carboxyl-terminal tyrosination/detyrosination cycle of alpha-tubulin, incorporation of NO2Tyr shows apparent irreversibility. Nitrotyrosination of alpha-tubulin induces alterations in cell morphology, changes in microtubule organization, loss of epithelial-barrier function, and intracellular redistribution of the motor protein cytoplasmic dynein. These observations imply that posttranslational nitrotyrosination of alpha-tubulin invokes conformational changes, either directly or via allosteric interactions, in the surface-exposed carboxyl terminus of alpha-tubulin that compromises the function of this critical domain in regulating microtubule organization and binding of motor- and microtubule-associated proteins. Collectively, these observations illustrate a mechanism whereby free NO2Tyr can impact deleteriously on cell function under pathological conditions encompassing reactive nitrogen species production. The data also yield further insight into the role that the alpha-tubulin tyrosination/detyrosination cycle plays in microtubule function.
Two-dimensional spectroscopy of molecular excitons in a model dimer system (2014)

The physics of molecular excitons has been the subject of many recent studies using electronic two-dimensional photon-echo spectroscopy (2DPE), particularly in the context of light harvesting in photosynthesis. Since the spectra for multichromophoric aggregates are congested, particularly so at room temperature, we present a study of a model dimer comprised of identical chromophores with a well defined electronic coupling strength, to provide clear signatures for coherences between vibronic excitons in 2D spectra. We begin by describing the design of a broadband passively phase-stabilized interferometer for collection of 2D spectra, which also allows for the investigation of state preparation in 2D spectroscopy by using shaped excitation pulses. In experiments on the model dimer we observe strong oscillating off-diagonal features in the 2D spectra which are present only before the onset of dephasing, which occurs in less than 100 fs due to strong system-bath coupling. This is in contrast with the parent dye, where low amplitude oscillations associated with Raman active vibrations persist for several ps following excitation. The results of this comparative study indicate that the signals observed earlier in photosynthetic proteins likely reflect vibrational motion in isolated pigments, and not delocalized quantum coherence. While long-lived vibrational coherences are of questionable biological relevance at face value, we conclude with a discussion on initial findings using coherently controlled 2D spectroscopy, where we observe long-lived signatures associated to vibronic coherences at room temperature. These results point to new directions of study using multidimensional spectroscopy to unravel the role of coherence in excitation energy transfer in molecular aggregates in an experimentally direct fashion.
Metabolic activation and drug toxicity (1982)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetabolic activation and drug toxicitySidney D. NelsonCite this: J. Med. Chem. 1982, 25, 7, 753–765Publication Date (Print):July 1, 1982Publication History Published online1 May 2002Published inissue 1 July 1982https://pubs.acs.org/doi/10.1021/jm00349a001https://doi.org/10.1021/jm00349a001research-articleACS PublicationsRequest reuse permissionsArticle Views1467Altmetric-Citations172LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Unidirectional rotary motion in a liquid crystalline environment: Color tuning by a molecular motor (2002)

Life could not exist without motion induced by a variety of molecular motors. The construction of artificial motors by chemical synthesis, which can power motions that lead to macroscopic detectable effects in a system, is a major endeavor in contemporary science. To move toward this goal, a host-guest system, composed of a nematic liquid crystal film doped with a chiral light-driven molecular motor, is assembled. Irradiation of the film results in unidirectional rotary motion of the molecular motor, which induces a motion of the mesogenic molecules leading to a molecular reorganization and, as a consequence, a change in the color of the film. In this way, by control of the rotary motion at the molecular level, color tuning over the entire visible spectrum is achieved. These findings demonstrate that a molecular motor can exert a visually observable macroscopic change in a material.
The β-Catenin/T-Cell Factor/Lymphocyte Enhancer Factor Signaling Pathway Is Required for Normal and Stress-Induced Cardiac Hypertrophy (2006)

In cells capable of entering the cell cycle, including cancer cells, beta-catenin has been termed a master switch, driving proliferation over differentiation. However, its role as a transcriptional activator in terminally differentiated cells is relatively unknown. Herein we utilize conditional, cardiac-specific deletion of the beta-catenin gene and cardiac-specific expression of a dominant inhibitory mutant of Lef-1 (Lef-1Delta20), one of the members of the T-cell factor/lymphocyte enhancer factor (Tcf/Lef) family of transcription factors that functions as a coactivator with beta-catenin, to demonstrate that beta-catenin/Tcf/Lef-dependent gene expression regulates both physiologic and pathological growth (hypertrophy) of the heart. Indeed, the profound nature of the growth impairment of the heart in the Lef-1Delta20 mouse, which leads to very early development of heart failure and premature death, suggests beta-catenin/Tcf/Lef targets are dominant regulators of cardiomyocyte growth. Thus, our studies, employing complementary models in vivo, implicate beta-catenin/Tcf/Lef signaling as an essential growth-regulatory pathway in terminally differentiated cells.
Effects of volume and surface property in hydrolysis by acetylcholinesterase. The trimethyl site (1984)

beta-Substituted ethyl acetates, XCH2CH2OCOCH3, have been prepared, and their hydrolysis by acetylcholinesterase has been studied. Log of enzymic reactivity, normalized for intrinsic reactivity in hydrolysis by hydroxide, log (kcat/Km)n, rises linearly with increasing refraction volume, MR (or RD25), for substrates with beta-X = H, Cl, Br, CH3CH2, (CH3)2CH, (CH3)2S+, (CH3)3N+, and (CH3)3C. Larger substituents may be accommodated, (CH3)3Si and (CH3CH2)3N+, with no further increase in rate. Substrates with beta-substituents CH3S, CH3S(O), (CH3)3N+(OH), and CH3S(O2) are less reactive than consistent with the relation with MR by factors of 5-40, indicating that hydrophobic surface and desolvation of the substrate--enzyme interface may be necessary for maximum reactivity correlated with MR. Values of log (kcat/Km)n for substrates with beta-substituents X = CH3S, Cl, Br, CH3CH2, (CH3)2CH, (CH3)3C, and (CH3)3Si rise linearly with increasing hydrophobicity, pi, but reactivity of substrates with X = (CH3)3N+ and (CH3)2S+ are more reactive than consistent with a relation to pi by factors of 300 and 40 and with X = CH3S(O2), CH3S(O), and (CH3)2N+(OH), by factors of 7-100. Reactivity appears related to (i) volume of the beta-substituent and its fit in its subsite, which is trimethyl rather than anionic, and (ii) the hydrophobicity of its surface.
A review of multi-objective optimization: Methods and its applications (2018)

Several reviews have been made regarding the methods and application of multi-objective optimization (MOO). There are two methods of MOO that do not require complicated mathematical equations, so the problem becomes simple. These two methods are the Pareto and scalarization. In the Pareto method, there is a dominated solution and a non-dominated solution obtained by a continuously updated algorithm. Meanwhile, the scalarization method creates multi-objective functions made into a single solution using weights. There are three types of weights in scalarization which are equal weights, rank order centroid weights, and rank-sum weights. Next, the solution using the Pareto method is a performance indicators component that forms MOO a separate and produces a compromise solution and can be displayed in the form of Pareto optimal front, while the solution using the scalarization method is a performance indicators component that forms a scalar function which is incorporated in the fitness function.
A randomized comparison of external and internal cardioversion of chronic atrial fibrillation. (1992)

Internal cardioversion is more effective than external cardioversion in restoring sinus rhythm and is as safe as external cardioversion in patients with chronic AF. The recurrence rate of AF is the same after both types of cardioversion. If conventional electrical cardioversion is ineffective, internal cardioversion should be attempted. The combination of low-dose amiodarone and external or internal cardioversion may result in maintaining sinus rhythm long-term in patients with refractory AF.
The vertical replacement-gate (VRG) process for scalable general-purpose complementary logic (2002)

A major challenge in scaling metal-oxide-semiconductor field-effect transistors (MOSFETs) is controlling the gate length, L/sub G/. Variable L/sub G/ leads to variable current drive, requiring conservative digital designs, and to device mismatch that makes the fastest transistors unusable in precision analog designs. The vertical, replacement-gate (VRG) process uses the thickness of a deposited film to precisely define the gate length, while preserving the small gate overlap capacitances and shallow, self-aligned source/drain extensions that are critical to modern MOSFETs. In brief, a silicon device pillar is grown through a multilayer sandwich, whose center layer is later removed and replaced by the gate, and whose upper and lower layers provide dopants for the source/drain extensions. The gate dielectric can be thin, high-quality, thermal SiO/sub 2/ grown on [100]-oriented single-crystal silicon. Previous vertical MOSFET schemes inherently result in poor gate length control, high gate overlap capacitances, or low-quality gate oxides. The first VRG-MOSFETs are competitive with optimized short-channel planar MOSFETs. L/sub G/=200 nm (L/sub ch//spl Gt/190 nm) VRG-n MOSFETs have I/sub on/=1.1 mA//spl mu/m with I/sub off/=11 pA//spl mu/m (and subthreshold swing s=76 mV/dec).
Colloidal Silicic Acid for Oral and Topical Treatment of Aged Skin, Fragile Hair and Brittle Nails in Females (1993)

In an open study, women with biologically aged skin and fragile or thin hair, or brittle nails were treated orally with 10 ml colloidal silicic acid (Silicol) once daily for 90 days and applied colloidal silicic acid to the face for 10 min twice daily. Of the 50 subjects treated, three withdrew from treatment after 30 days because of excessive drying of the facial skin due to topical application. In the remaining 47 subjects there was statistically significant improvement in the thickness and turgor of the skin, wrinkles and condition of the hair and nails. The number of mottles also declined, but the change was not statistically significant. Ultrasound measurements did not detect any statistically significant change in the thickness of the epidermis or elasticity of the skin, but there was a significant increase in the thickness of the dermis.
New Potent Antibacterial Oxazolidinone (MRX-I) with an Improved Class Safety Profile (2014)

Oxazolidinones comprise an important class of antibacterial protein synthesis inhibitors. Myelosuppression and monoamine oxidase inhibition (MAOI) are key independent causes for limiting adverse effects in therapy with the sole approved drug of this class, linezolid. This annotation describes a novel oxazolidinone agent, (S)-5-((isoxazol-3-ylamino)methyl)-3-(2,3,5-trifluoro-4-(4-oxo-3,4-dihydropyridin-1(2H)-yl)phenyl)oxazolidin-2-one (MRX-I), distinguished by its high activity against Gram-positive pathogens coupled with markedly reduced potential for myelosuppression and MAOI. The medical need, medicinal chemistry rationale, preclinical data, and phase I clinical trial summary for this new agent are reviewed herein.
Optical Waveguide Modulators (1975)

A tutorial survey of recent work on optical waveguide modulators in electrooptic, acoustooptic, and magnetooptic materials is presented. Methods for realizing waveguiding layers in modulating materials and various modulator configurations are considered.
Robust multi-sensor classification via joint sparse representation (2011)

Abstract—In this paper, we propose a novel multi-task multivariate (MTMV) sparse representation method for multi-sensor classification, which takes into account correlations between sensors simultaneously while considering joint sparsity within each sensor’s observations. This approach can be seen as the generalized model of multi-task and multivariate Lasso, where all the multi-sensor data are jointly represented by a sparse linear combination of training data. We further modify our MTMV model by including a clutter noise term that is also assume to be sparse in feature domain. An efficient algorithm based on alternative direction method is proposed for both models. Extensive experiments are conducted on real data set and the results are compared with the conventional discriminative classifiers to verify the effectiveness of the proposed methods. I.
Expanding the Genetic Code of <i>Escherichia coli</i> with Phosphoserine (2011)

O-Phosphoserine (Sep), the most abundant phosphoamino acid in the eukaryotic phosphoproteome, is not encoded in the genetic code, but synthesized posttranslationally. Here, we present an engineered system for specific cotranslational Sep incorporation (directed by UAG) into any desired position in a protein by an Escherichia coli strain that harbors a Sep-accepting transfer RNA (tRNA(Sep)), its cognate Sep-tRNA synthetase (SepRS), and an engineered EF-Tu (EF-Sep). Expanding the genetic code rested on reengineering EF-Tu to relax its quality-control function and permit Sep-tRNA(Sep) binding. To test our system, we synthesized the activated form of human mitogen-activated ERK activating kinase 1 (MEK1) with either one or two Sep residues cotranslationally inserted in their canonical positions (Sep(218), Sep(222)). This system has general utility in protein engineering, molecular biology, and disease research.
Line Shapes in Nuclear Paramagnetism (1948)

This note discusses briefly several methods of describing the width and shape of the resonances characteristic of nuclear paramagnetism. Use of the so-called moments of the shape function is illustrated by an experimental determination of a root mean square line width which is in substantial agreement with a calculation by Van Vleck. The solutions of the Bloch equations, which lead to the Lorentz shape function traditional in the theory of radiation- and collision-broadened lines, are compared with susceptibility curves based on a Gauss absorption curve. A significant difference between the two dispersion curves serves as a criterion for determining whether or not either of these two shapes closely approximates to a given experimental curve, and experimental examples of each are given.For comparison of shape functions, several well-known specializations of the Kronig-Kramers relations are employed. The collection of these formulae may incidentally prove convenient and useful to those engaged in studies of nuclear paramagnetism.