gebhart/patrepeval huggingface dataset:
The p<i>K</i><sub>a</sub>of the General Acid/Base Carboxyl Group of a Glycosidase Cycles during Catalysis:  A<sup>13</sup>C-NMR Study of<i>Bacillus circulans</i>Xylanase (1996)

The 20 kDa xylanase from Bacillus circulans carries out hydrolysis of xylan via a two-step mechanism involving a covalent glycosyl-enzyme intermediate. In this double-displacement reaction, Glu78 functions as a nucleophile to form the intermediate, while Glu172 acts as a general acid catalyst during glycosylation, protonating the departing aglycone, and then as a general base during deglycosylation, deprotonating the attacking water. The dual role of Glu172 places specific demands upon its ionization states and hence pKa values. 13C-NMR titrations of xylanase, labeled with [delta-13C]glutamic acid, have revealed pKa values of 4.6 and 6.7 for Glu78 and Glu172, respectively. These agree well with the apparent pKa values obtained from a study of the pH dependence of kcat/Km and demonstrate that, at the enzyme's pH optimum of 5.7, the nucleophile Glu78 is deprotonated and the general acid Glu172 initially protonated. Remarkably, the pKa for Glu172 drops to 4.2 in a trapped covalent glycosyl-enzyme intermediate, formed by reaction with 2', 4'-dinitrophenyl 2-deoxy-2-fluoro-beta-xylobioside [Miao et al. (1994) Biochemistry 33, 7027-7032]. A similar pKa is measured for Glu172 when a glutamine is present at position 78. This large decrease in pKa of approximately 2.5 units is consistent with the role of Glu172 as a general base catalyst in the deglycosylation step and appears to be a consequence of both reduced electrostatic repulsion due to neutralization of Glu78 and a conformational change in the protein. Such "pKa cycling" during catalysis is likely to be a common phenomenon in glycosidases.
Synthesis of Optically Active 2-Chloromethyl-2-oxazolines by the Ortho-ester Codensation Method Using Triethyl Orthochloroacetate (1999)

A set of optically active 2-chloromethyl-2-oxazolines was synthesized by condensation of optically active 2-amino alcohols with methyl onhochloroacetate which was prepared conveniently from triethyl orthoacetate by chlorination using rert-butyl hypochlorite.' In refluxing 1.2-dichloroethane in the presence of TFA as a catalyst
Group decision making and social learning (2016)

Social learning or learning from actions of others is a key focus of microeconomics; it studies how individuals aggregate information in social networks. Following the seminal work of Aumann, a large literature studies the strategic interaction of agents in a social network, where they receive private information and act based upon that information while also observing the actions of each other. These observations are in turn informative about other agents' private signals; information that can be then used in making future decisions. By the same token, agents engage in group discussions to benefit from private information of others and come up with better decisions that aggregate every body's information as efficiently as possible. We begin by considering the decision problems of a Bayesian agent in a social learning scenario. As the Bayesian agent attempts to infer the true state of the world from her sequence of private signals and observations of actions of others, her decision problems at every epoch can be cast recursively; curbing some of the complexities of the decision scenario, but only to a limited extent. In a group decision scenario, the initial private signals of the agents constitute a state space and the ultimate goal of the agents is get informed about the private signals of each other. The Bayesian agent is initially informed of only her own signal; however, as her history of interactions with other group members becomes enriched, her knowledge of the possible private signals that others may have observed also gets refined; thus enabling her to make better decisions. Bayesian calculations in the social learning setting are notoriously difficult. Successive applications of Bayes rule to the entire history of past observations lead to forebodingly complex inferences: due to lack of knowledge about the global network structure, and unavailability of private observations, as well as third-party interactions that precede every decision. This has given rise to a large literature on non-Bayesian social learning that suggest the use of decision-making heuristics, not only for mathematical tractability but also on the grounds that they are better descriptors of the bounded rational behaviors that are observed in reality: people rely on some simplifications of their environment to be able to analyze it faster and more reliably. These heuristics may be fitted for simple one-shot decision making but they are often not suited for handling the complexities of a public discussion or for making group decisions. As a result, many inefficiencies arise in the outcome of such discussions and their roots can be traced to the underlying heuristic decisionmaking mechanisms. These and other issues relating to heuristic decision making constitute the main focus of this paper.
Growth CO2 Consumption, and H2 Production of Anabaena Variabilis ATCC 29413-U Under Different Irradiances and CO2 Concentrations (2006)

Hydrogen production by cultivation of cyanobacteria in photobioreactors offers a clean and renewable alternative to thermochemical or electrolytic hydrogen production technologies with the added advantage of CO2 mitigation. The objective of this study is to experimentally investigate the CO2 consumption, growth, and H2 production of the cyanobacteria Anabaena variabilis ATCC 29413-U under atmosphere containing argon and CO2. Parameters investigated are irradiance and initial CO2 mole fraction in the gas phase. The CO2 consumption half-time, defined as the time at which the CO2 concentration in the gas phase decreases to half of its initial value, appears to be an appropriate time scale for modeling cyanobacterial CO2 consumption, growth, and H2 production. The half-time depends on both the initial CO2 mole fraction and the irradiance. Also, two regimes of growth have been identified depending on irradiance. Below 5,000 lux, the irradiance and the initial CO2 mole fraction have a coupled effect on cyanobacterial growth. Above 5,000 lux, growth depends only on the initial CO2 mole fraction. Furthermore, the optimum initial CO2 mole fraction around 0.05 has been identified for maximum growth and CO2 consumption rates. The growth and CO2 consumption were not inhibited by irradiance up to about 16,000 lux. Finally, the proposed empirical models can be used in conjunction with mass transfer and light transfer models to design and optimize the operating conditions of a photobioreactor for maximum hydrogen production and/or CO2 consumption.
High surface area, amorphous titania with reactive Ti<sup>3+</sup>through a photo-assisted synthesis method for photocatalytic H<sub>2</sub>generation (2017)

A facile approach for the preparation of high surface area, Ti<sup>3+</sup>containing titania with good activity for photocatalytic H<sub>2</sub>production is reported.
Altered Temporal Organization of Plasma Insulin Oscillations in Chronic Renal Failure (2002)

Chronic renal failure (CRF) is associated with mechanistically unexplained impaired insulin sensitivity. Erratic insulin secretory patterns typify other states of insulin resistance. We sought to investigate possible alterations of plasma insulin oscillations in CRF. We assessed high- and low-frequency insulin and glucose oscillations in 7 male CRF patients and 11 controls by multiparametric deconvolution analysis and cluster analysis, approximate entropy (ApEn) statistic, and cross-ApEn statistics. Insulin sensitivity was appraised by euglycemic hyperinsulinemic clamps. Despite impaired glucose disappearance rates in CRF, fasting and 24-h mean insulin and glucose concentrations did not differ between patients and controls. However, patients showed a 2.5-fold increase of insulin elimination half-life, reduced frequency of both rapid (6.1 +/- 0.4 vs. 7.1 +/- 0.2 h(-1), P < 0.001) and slow oscillations of insulin release (0.54 +/- 0.11 vs. 0.71 +/- 0.1 h(-1), P < 0.001), lack of acceleration and paradoxically more orderly slow insulin and glucose pulses after meals, and increased temporal coupling between insulin and glucose patterns (cross-ApEn: 0.58 +/- 0.13 vs. 1.37 +/- 0.23, P < 0.001). Postprandial glucose intolerance was inferable by prolonged and amplified blood glucose excursions despite exaggerated insulin bursts of almost 3-fold higher area. In summary, CRF is associated with a complex disruption of the temporal organization of insulin release, which differs from abnormalities observed to date in other states of insulin resistance.
Optimal scanning strategy for vehicular Wi-Fi (2011)

As many open Wi-Fi access points are deployed in hotspots for public use, research is being conducted to use them opportunistically from moving vehicles. A key to make use of the short, opportunistic connections between moving vehicles and open Wi-Fi access points is the ability to scan for open access points quickly, but current implementation of the IEEE 802.11 standards has a long scanning delay. In this paper we compare some scanning methods in the literature and propose an optimal scanning strategy that minimizes the scanning time for vehicular Wi-Fi. Through mathematical analysis and computer simulations, we show that this strategy can find an open access point in the minial average number of scans and thus gives moving vehicles longer connections to receive and deliver data.
Elektrostatische Kontrolle der Molekül‐ und der Kristallstruktur eines olefinischen Doppelbetains (1990)

Eine chirale Konformation im Festkörper sowie eine Stapelstruktur mit rautenförmigen Hohlräumen sind die Folge elektrostatischer Wechselwirkungen der vier geladenen Substituenten in 1 . Dieses Z ‐konfigurierte Doppelbetain ist ausgehend von Dichlormaleinsäureanhydrid und 4‐Dimethylaminopyridin in drei Stufen erhältlich. magnified image
Synthesis and ring‐opening polymerization of 2‐acetoxymethyl‐2‐alkyltrimethylene carbonates and of 2‐methoxycarbonyl‐2‐methyltrimethylene carbonate; a comparison with the polymerization of 2,2‐dimethyltrimethylene carbonate (1996)

Abstract The polymerization of 2‐acetoxymethyl‐2‐alkyltrimethylene carbonates (alkyl = methyl: AMTC, alkyl = ethyl: AETC) and of 2‐methoxycarbonyl‐2‐methyltrimethylene carbonate (MMTC) in toluene with sec ‐butyllithium as initiator results in the respective polymer with yields between 78% and 88%. The analysis of the polymer microstructure by means of NMR spectroscopy reveals linear chains without branching due to an attack of the active chain end at the ester moiety of the repeating units. Poly(MMTC) and poly(‐AETC) afford crystalline materials upon precipitation from solution while poly‐(AMTC) is amorphous; after quenching from the melt all materials are amorphous. Copolymerization of AMTC, AETC and MMTC with 2,2‐dimethyltrimethylene carbonate (DTC) results in random copolymers. The kinetics of the polymerization of AETC and MMTC revealed that the ester side chain enhances the rate of propagation compared to the polymerization of DTC. The apparent rate constants of propagation in toluene with lithium alcoholate as active sites at 23°C were determined to be k app DTC = 4 ċ 10 −3 s −1 , k app AETC = 4,28 ċ 10 −2 s −1 , and k app MMTC = 2,57 ċ 10 −2 s −1 . Studies of ring‐chain equilibria in solution of tetrahydrofuran revealed that on the basis of the theory of Jacobson‐Stockmayer the characteristic ratios of the polymers are C ∞ PDTC = 7,1, C ∞ PMMTC = 8,6, C ∞ PAETC = 9,9, and C ∞ PAMTC = 13,4.
Activation of signal transducer and activator of transcription 3 correlates with cell proliferation and renal injury in human glomerulonephritis (2008)

The present study has identified STAT3 activation in normal human kidney and a marked increase in STAT3 activation in many forms of glomerulonephritis. The correlation of STAT3 activation with clinical and histologic parameters suggests that this pathway plays an important role in the pathogenesis of kidney disease. Furthermore, localization of STAT3 activation to individual cell types suggests that this pathway may play a pivotal role in promoting renal inflammation and fibrosis.
Premetastatic niche: ready for new therapeutic interventions? (2012)

Premetastatic niche is defined as a fertile microenvironment that forms in metastatic target organ and facilitates the invasion, survival and/or proliferation of metastatic tumor cells, providing a novel mechanism for the promotion of metastasis. Drugs targeting premetastatic niche could represent a new promising therapeutic approach in the treatment of bone metastases.
Suppression of exciton annihilation at high current densities in organic light-emitting diode resulting from energy-level alignments of carrier transport layers (2008)

We manufactured an organic light-emitting diode (OLED) in which the hole and electron transport layers are chemically doped with p- and n-type dopants and energy levels in between neighboring carrier transport layers and emitting molecules are aligned. From the results of the electroluminescence (EL) characteristics of the OLED, we found that (1) the OLED has an extremely low driving voltage of 2.65±0.050.05V at a current density of 100mA∕cm2; (2) the onset voltage of EL (≈2.4V) corresponds to the photon energy of emitting molecules (≈2.5eV), while the onset voltage of currents is ≈1.8V; and (3) a decrease in EL efficiency at high current densities can be suppressed by matching the energy levels.
Krüppel-Like Factor 4 Acts as an Oncogene in Colon Cancer Stem Cell-Enriched Spheroid Cells (2013)

Cancer stem cells (CSCs), a rare population in any type of cancers, including colon cancer, are tumorigenic. It has been thought that CSCs are responsible for cancer recurrence, metastasis, and drug resistance. Isolating CSCs in colon cancers is challenging, and thus the molecular mechanism regulating the self-renewing and differentiation of CSCs remains unknown. We cultured DLD-1 cells, one of types of cells derived from colon cancers, in serum-free medium to obtain spheroid cells. These cells possessed the characteristics of CSCs, with the expression of CD133, CD166, Lgr5, and ALDH1, higher capacities of chemo-resistance, migration, invasion, and tumorigenicity in vitro and in vivo than the adherent DLD-1 cells. Krüppel-like factor 4 (KLF4) is essential factor for maintaining self-renewal of adult and embryonic stem cells. It has been used to induce pluripotent stem cells (iPS) from somatic cells. Since KLF4 is expressed in colon cancer cells, we investigated its role in spheroid cells isolated from DLD-1 cells and found that KLF4 was overexpressed only in spheroid cells and reducing the expression of KLF4 by short-hairpin RNA significantly decreased the capacities of these cells to resist the chemicals, migrate, invade, and generate tumors in vitro and in vivo. The spheroid cells with reduced KLF4 expression also had decreased expression of CSCs markers and mesenchymal markers. Taken together, culturing DLD-1 cells in serum-free medium enriches CSCs and the expression of KLF4 is essential for the characteristics of CSCs in DLD-1; thus KLF4 can be a potential therapeutic target for treating colon cancer.
British Statutes in the Emergent Nations of North America: 1606-1949 (1963)

British Statutes in the Emergent Nations of North America: 1606–1949 Get access Elizabeth Gaspar Brown Elizabeth Gaspar Brown Research Associate in Law †The University of Michigan Search for other works by this author on: Oxford Academic Google Scholar American Journal of Legal History, Volume 7, Issue 2, April 1963, Pages 95–136, https://doi.org/10.2307/844250 Published: 01 April 1963
Single well sonic imaging of near borehole structure (2003)

Summary form only given, as follows. Modern exploration for oil-bearing reservoirs involves characterization of subsurface structural features. Sonic measurements using an array of receivers have made possible the acquisition of entire waveforms, allowing the processing of arrivals that appear later than the compressional headwave. Secondary sonic arrivals (reflections from near-borehole structural features) are recorded and processed to form an image of the formation structure surrounding the borehole, in a manner similar to seismic migration. The processing technique is illustrated with both synthetic data and data from a real borehole experiment performed in Alaska. Images are shown of near-borehole structure features out to a distance of 18 m from the borehole. Possible use of this imaging technique include horizontal well logging, structural dip and contour determination, imaging faults, salt domes, pinnacle reefs and fracture zones, and steam flood monitoring for enhanced oil recovery.
Pedestrian Detection with Semantic Regions of Interest (2017)

For many pedestrian detectors, background vs. foreground errors heavily influence the detection quality. Our main contribution is to design semantic regions of interest that extract the foreground target roughly to reduce the background vs. foreground errors of detectors. First, we generate a pedestrian heat map from the input image with a full convolutional neural network trained on the Caltech Pedestrian Dataset. Next, semantic regions of interest are extracted from the heat map by morphological image processing. Finally, the semantic regions of interest divide the whole image into foreground and background to assist the decision-making of detectors. We test our approach on the Caltech Pedestrian Detection Benchmark. With the help of our semantic regions of interest, the effects of the detectors have varying degrees of improvement. The best one exceeds the state-of-the-art.
Serine Acetyltransferase Involved in Cysteine Biosynthesis from Spinach: Molecular Cloning, Characterization and Expression Analysis of cDNA Encoding a Plastidic Isoform (2001)

A cDNA clone that encodes a chloroplast-localizing isoform of serine acetyltransferase (SATase) (EC 2.3.1.30) was isolated from spinach (Spinacia oleracea L.). The cDNA encodes a polypeptide of 347 amino acids containing a putative transit peptide of ca. 60-70 amino acids at the N-terminal. Deduced amino acid sequence of SATase from spinach exhibited homology with other SATases from plants. DNA blot hybridization analysis showed the presence of 2-3 copies of Sat gene in the genome of spinach. RNA blot hybridization analysis indicated the constitutive expression of Sat gene in green and etiolated seedlings of spinach. Bacterial expression of the cDNA could directly rescue the cysteine auxotrophy of Escherchia coli caused by a lack of SATase locus (cysE). Catalytically active SATase protein was produced in E. coli cells. L-Cysteine, an end product of the cysteine biosynthetic pathway, inhibited the activity of recombinant spinach SATase, indicating the regulatory function of SATase in this metabolic pathway. A chloroplastic localization of this spinach SATase was revealed by the analyses of transgenic plant expressing transit peptide of SATase-beta-glucuronidase (GUS) fusion protein, and transient expression using the transit peptide-green fluorescent protein (GFP) fusion protein. The result from in vitro translation analysis suggests that this cDNA may encode both plastidic and cytosolic SATases.
Results of the DESC test facility's efforts to improve the quality of electronic replacement parts (2002)

Data indicating an increase in the quality of defense electronics supply center (DESC) sampled devices being supplied for the military services over the last few years are presented. Through continued testing and analysis a database that depicts the overall quality of the electronic parts DESC manages was constructed. DESC manages 93 federal supply classes (FSCs), and the test facility performs incoming inspection on selected new buys, monitors and samples the material in storage, and performs support testing for DESC and other government agencies. Test facility results serve to identify and correct deficient material before it is placed in inventory and to monitor the quality of older devices already in storage. Rejected lots are returned to the manufacturers, corrective actions required, and future purchases of these same and similar part-types screened. Feedback to suppliers and corrective actions are key ingredients to continuously improving the quality of electronic parts received by DESC.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Electro-Optical Systems for Dynamic Display of X-ray Diffraction Images (1970)

Abstract Various electro-optical systems have been reported which permit intensification of X-ray diffraction patterns and thus a decrease in exposure time for recording and display of the X-ray images. Prior to 1966, all such electro-optical systems incorporated a large format X-ray image intensifier of the same type as conventionally used for medical and industrial fluoroscopy. In the past four years, a number of different systems have been reported which are superior to those developed prior to 1966. These systems may be grouped into two main categories, the large format variety for Laue diffraction applications, and the small format variety for topographic applications. The purpose of the present paper is to describe the particular characteristics of both the large format and small format systems and to discuss the advantages and disadvantages associated with each type. Based on actual performance characteristics it will be shown that: 1. A multiple stage image intensifier system coupled to an external fluorescent screen is the most sensitive and only truly instantaneous system; it can be used with very weak X-ray intensities, the resolution is currently limited by the external fluorescent screen to 42μ the system is extremely versatile in that it can be used both for large format recording of Laue patterns as well as for small format recording of X-ray topographe; the system has a very long lifetime since nothing is altered by X-radiation. 2. An X-ray sensitive vidicon is the least sensitive; it must be used with extremely high intensity X-rays or long exposure times; the resolution is the highest at approximately 15μ and is limited by either bandwidth of the television system, the thickness of the X-ray sensitive target or the size of the electron beam at the target; due to the small size of the X-ray sensitive target the system can only be used for small format recording of X-ray topographs; the lifetime of the system is short since X-radiation causes degradation of the target.
Taking Environmental Health Education Seriously (2000)

Abstract Faced with an explosion in the number and complexity of environmental risks to health, nurses must broaden their view of the environment to include the intricate interplay of human life with physical, chemical, biological, and social forces. Increasing students' awareness and knowledge about the basic principles and concepts of environmental health can be achieved through minor expansion of curricular content. This article describes how Howard University incorporated environmental health into a nursing curriculum through stimulating, innovative relationships with three nonacademic agencies. Urban and rural environmental threats pose significant exposure risks to individual and community health, especially in vulnerable populations. For example, chemical hazards, which account for a significant portion of environmental and occupational exposure, individually or in combination, place children at great risk (1–3). Knowledge of basic environmental principles concerning exposure sources, environmental...
γ-Secretase Inhibitor Reduces Allergic Pulmonary Inflammation by Modulating Th1 and Th2 Responses (2009)

These data suggest that GSI directly regulates Th1 and Th2 responses in allergic pulmonary inflammation through a Notch signaling-dependent pathway and that GSI is of high therapeutic value for treating asthma by inhibiting airway inflammatory responses.