gebhart/patrepeval huggingface dataset:
Effect of poly(ethylene glycol) diacrylate concentration on network properties and <i>in vivo</i> response of poly(β‐amino ester) networks (2010)

Poly(β-amino ester) networks have shown promise as tissue scaffolds. The objective of this work was to examine the effect of changing poly(ethylene glycol) diacrylate concentration on poly(β-amino ester) network properties and to assess the degradable polymers' in vivo response, using magnetic resonance imaging (MRI) and immunohistochemistry. The networks were synthesized from hexanediol diacrylate (HDDA), poly(ethylene glycol) diacrylate (PEGDA), and a primary amine, 3-methoxypropylamine (3-MOPA), with a fixed overall molar ratio of diacrylate to amine. Network properties were verified to insure that the networks possessed equivalent initial properties and structure other than chemistry. The effect of varying PEGDA concentration on water content, mass loss, and modulus was determined, where increasing the concentration of PEGDA increases both water content, mass loss rate, and decreases modulus. We also show that manipulating the network composition at ratios of 0:100, 10:90 and 25:75 (PEGDA:HDDA) does not elicit a major inflammatory response to subcutaneous implantation of the networks in mice. This work provides a foundation for tailoring poly(β-amino ester) networks, based on degradation rate and modulus, as a means to tune the polymer properties for various biomedical applications.
Engineering of Cyclodextrin Glycosyltransferase Reveals pH-Regulated Mechanism of Enhanced Long-Chain Glycosylated Sophoricoside Specificity (2020)

Sophoricoside glycosylated derivatives, especially long-chain glycosylated sophoricosides (LCGS), have greatly improved water solubility compared with sophoricoside. Here, cyclodextrin glycosyltransferase from <i>Paenibacillus macerans</i> (<i>Pm</i>CGTase) was employed for sophoricoside glycosylation. Saturation mutagenesis of alanine 156, alanine 166, glycine 173, and leucine 174 was performed due to their nonconservative properties among α-, β-, and γ-CGTases with different product specificities. Variants L174P, A156V/L174P, and A156V/L174P/A166Y greatly improved the product specificity for LCGS. pH significantly affected the extent of glycosylation catalyzed by the variants. Further investigations revealed that the pH-regulated mechanism for LCGS synthesis mainly depends on a disproportionation route at a lower pH (pH 4) and a cyclization-coupling route at a higher pH (pH 8) and equivalent effects of cyclization-coupling and disproportionation routes at pH 5. Whereas short-chain glycosylated sophoricosides (SCGS) are primarily produced via disproportionation of maltodextrin at pH 4 and secondary disproportionation of LCGS at pH 8. At pH 5, SCGS synthesis mainly depends on a hydrolysis route by the wild type (WT) and a secondary disproportionation route by variant A156V/L174P/A166Y. Kinetics analysis showed a decreased <i>K<sub>m</sub></i> value of variant A156V/L174P/A166Y. Dynamics simulation results demonstrated that the improved LCGS specificity of the variant is possibly attributed to the enhanced affinity to long-chain substrates, which may be caused by the changes of hydrogen bond interactions at the -5, -6, and -7 subsites. Our results reveal a pH-regulated mechanism for product specificity of CGTase and provide guidance for engineering CGTase toward products with different sugar chain lengths.<b>IMPORTANCE</b> The low water solubility of sophoricoside seriously limits its applications in the food and pharmaceutical industries. Long-chain glycosylated sophoricosides show greatly improved water solubility. Here, the product specificity of cyclodextrin glycosyltransferase (CGTase) for long-chain glycosylated sophoricosides was significantly affected by pH. Our results reveal the pH-regulated mechanism of the glycosylated product specificity of CGTase. This work adds to our understanding of the synthesis of long-chain glycosylated sophoricosides and provides guidance for exploring related product specificity of CGTase based on pH regulation.
The power of obfuscation techniques in malicious JavaScript code: A measurement study (2012)

JavaScript based attacks have been reported as the top Internet security threats in recent years. Since most of the Internet users rely on anti-virus software to protect themselves from malicious JavaScript code, attackers exploit JavaScript obfuscation techniques to evade the detection of anti-virus software. To better understand the obfuscation techniques adopted by malicious JavaScript code, we conduct a measurement study. We first categorize observed JavaScript obfuscation techniques. Then we conduct a statistic analysis on the usage of different categories of obfuscation techniques in real-world malicious JavaScript samples. We also study the detection effectiveness of 20 most popular anti-virus software against obfuscation techniques. Based on the results, we analyze the cause of the popularity of obfuscation in malicious JavaScript code; the reason behind the choice of obfuscation techniques and the difference between benign obfuscation and malicious obfuscation. Moreover, we also provide suggestions for designing effective obfuscation detection approaches in future.
The Effect of an Inhaled Neutral Endopeptidase Inhibitor, Thiorphan, on Airway Responses to Neurokinin A in Normal Humans <i>In Vivo</i> (1992)

Neuropeptides such as neurokinin A (NKA) have been proposed as important mediators of bronchoconstriction and airway hyperresponsiveness in asthma. Inhaled NKA causes bronchoconstriction in patients with asthma, but not in normal subjects. This is possibly due to the activity of an endogenous neuropeptide-degrading enzyme: neutral endopeptidase (NEP). We investigated whether a NEP-inhibitor, thiorphan, reveals bronchoconstriction to NKA or NKA-induced changes in airway responsiveness to methacholine in normal humans in vivo. Eight normal male subjects participated in a double-blind crossover study, using thiorphan as pretreatment to NKA challenge. Dose-response curves to inhaled NKA (8 to 1,000 micrograms/ml, 0.5 ml/dose) were recorded on 2 randomized days 1 wk apart, and methacholine tests were performed 48 h before and 24 h after the NKA challenge. Ten minutes prior to NKA challenge the subjects inhaled either thiorphan (2.5 mg/ml, 0.5 ml) or placebo. To detect a possible nonspecific effect of thiorphan, we investigated the effect of the same pretreatment with thiorphan or placebo on the dose-response curve to methacholine in a separate set of experiments. The response was measured by the flow from standardized partial expiratory flow-volume curves (V40p), expressed in percent fall from baseline. NKA log dose-response curves were analyzed using the area under the curve (AUC) and the response to the highest dose of 1,000 micrograms/ml (V40p,1000). The methacholine dose-response curves were characterized by their position (PC40V40p) and the maximal-response plateau (MV40p). Baseline V40p was not affected by either pretreatment (p greater than 0.15).(ABSTRACT TRUNCATED AT 250 WORDS)
Inverse-Quantum-Engineering: A New Methodology for Designing Quantum Cascade Lasers (2010)

Bandstructure engineering has enabled a broad array of semiconductor heterostructure devices, such as quantum cascade lasers, whose performance is governed by a broad parameter space involving intertwined physical properties. Using present methods it is challenging if not impossible to design structures that isolate a specific physical property that directly correlates with experimental results. To overcome this problem, we developed a new methodology, inverse quantum engineering (IQE), which employs an evolutionary algorithm to design families of structures with everything identical except for a specific physical property of our choosing. We show that IQE allows creation of model families of designs that isolate targeted experimental effects, thus allowing direct investigation of specific physical mechanisms and their often complicated and counter-intuitive interplay.
Fast Evaluation of Segmentation Quality with Parallel Computing (2017)

In digital image processing and computer vision, a fairly frequent task is the performance comparison of different algorithms on enormous image databases. This task is usually time-consuming and tedious, such that any kind of tool to simplify this work is welcome. To achieve an efficient and more practical handling of a normally tedious evaluation, we implemented the automatic detection system, with the help of MATLAB®’s Parallel Computing Toolbox™. The key parts of the system have been parallelized to achieve simultaneous execution and analysis of segmentation algorithms on the one hand and the evaluation of detection accuracy for the nonforested regions, such as a study case, on the other hand. As a positive side effect, CPU usage was reduced and processing time was significantly decreased by 68.54% compared to sequential processing (i.e., executing the system with each algorithm one by one).
A new charge redistribution D/A and A/D converter technique - pseudo C-2C ladder (2002)

C-2C ladder-based DAC architecture is potentially very attractive because of its small area, high speed and low power consumption. However, the parasitic capacitances on the interconnecting nodes of C-2C ladder restrict the linearity of the DAC. In this paper, a pseudo C-2C ladder structure is proposed. It compensates for the parasitic effect by adjusting the capacitor values in the ladders according to an optimization algorithm with further adjustments possible via an adaptive calibration method. Using this technique, a 3.3 V 9.2 mW 12-bit 1.4 MSPS successive approximation ADC was implemented in an HP0.5 /spl mu/m single-poly triple-metal CMOS technology.
Architecture of respiratory syncytial virus revealed by electron cryotomography (2013)

Human respiratory syncytial virus is a human pathogen that causes severe infection of the respiratory tract. Current information about the structure of the virus and its interaction with host cells is limited. We carried out an electron cryotomographic characterization of cell culture-grown human respiratory syncytial virus to determine the architecture of the virion. The particles ranged from 100 nm to 1,000 nm in diameter and were spherical, filamentous, or a combination of the two. The filamentous morphology correlated with the presence of a cylindrical matrix protein layer linked to the inner leaflet of the viral envelope and with local ordering of the glycoprotein spikes. Recombinant viruses with only the fusion protein in their envelope showed that these glycoproteins were predominantly in the postfusion conformation, but some were also in the prefusion form. The ribonucleocapsids were left-handed, randomly oriented, and curved inside the virions. In filamentous particles, they were often adjacent to an intermediate layer of protein assigned to M2-1 (an envelope-associated protein known to mediate association of ribonucleocapsids with the matrix protein). Our results indicate important differences in structure between the Paramyxovirinae and Pneumovirinae subfamilies within the Paramyxoviridae, and provide fresh insights into host cell exit of a serious pathogen.
Relationship of deoxycytidine kinase and cytoplasmic 5'-nucleotidase to the chemotherapeutic efficacy of 2-chlorodeoxyadenosine (1993)

The agent 2-chlorodeoxyadenosine (2-CdA) has chemotherapeutic activity in hairy cell leukemia (HCL) and in refractory chronic lymphocytic leukemia (CLL). The cytotoxic activity of 2-CdA requires the intracellular accumulation of 2-CdA nucleotides. Deoxycytidine kinase (dCK) and cytoplasmic 5'-nucleotidase (5'-NT) are the principal enzymes that phosphorylate 2-CdA and dephosphorylate 2-CdA 5'-monophosphate, respectively. The net accumulation of 2-CdA nucleotides may therefore depend on both dCK and 5'-NT. The purpose of the present experiments was to determine if there is a relationship between pretreatment levels of dCK and 5'-NT in HCL and in CLL cells, and the clinical outcome of 2-CdA treatment. As measured by a direct immunoassay for dCK in 25 CLL patients, and by a 5'-NT activity assay in 23 patients, mean dCK levels were significantly higher in 2-CdA responders than in nonresponders (P < .01), whereas mean 5'-NT levels were significantly lower in 2-CdA responders than in nonresponders (P < .05). Mean dCK levels were higher in six HCL 2-CdA responders than in one nonresponder, whereas mean 5'-NT levels were lower in the 2-CdA responders than in the nonresponder. These results suggest that both dCK and 5'-NT are determinants of 2-CdA responsiveness.
Preeclampsia: a bioinformatics approach through protein-protein interaction networks analysis (2012)

The applied methodology not only led to the identification of well known genes related to preeclampsia but also to propose new candidates poorly explored or completely unknown in the pathogenesis of preeclampsia, which eventually need to be validated experimentally. Moreover, new possible connections were detected between preeclampsia and other diseases that could open new areas of research. More must be done in this area to resolve the identification of unknown interactions of proteins/genes and also for a better integration of metabolic pathways and diseases.
Development of an <i>in vivo</i><sup>19</sup>F magnetic resonance method for measuring oxygen deficency in tumors (1991)

A 19F magnetic resonance spectroscopy (MRS) approach to measuring hypoxia in experimental tumors in rats at a field strength of 2.35 T has been investigated in a combined study of in situ and excised tumors. The detection of tumor hypoxia is based on the hypoxia marker approach which depends on the selective, covalent binding of a fluorinated 2-nitroimidazole to hypoxic cells. The 19F MRS measurement of in vivo hypoxia marker binding was made at a fixed postinjection time when unbound, circulating marker molecule concentrations had dropped below detectable levels. A correlation between 19F MRS and scintillation counting measures of tumor-bound, tritium-labeled hypoxia marker was observed. There was no correlation between integrated 19F MRS hypoxia marker signals and the in vivo 31P MRS parameters of hypoxia which have been developed to measure normal tissue ischemia. Radiolabeling studies and previous immunohistochemical studies with the fluorinated hypoxia marker support the conclusion that the 19F MRS approach has promise as a physically noninvasive guide to the use of hypoxia-dependent therapies at clinically usable MRS field strengths.
Ga1−<i>x</i>Al<i>x</i>As LED Structures Grown on GaP Substrates (1972)

Ga1−xAlxAs light-emitting diode structures have been grown on GaP substrates by the liquid-phase-epitaxial method. In spite of the large differences in lattice constants and thermal-expansion coefficients, room-temperature efficiencies up to 5.5% in air have been observed for a peak emission of 8500 Å. Previously, in order to achieve high external efficiencies it was necessary to grow thick Ga1−xAlxAs layers on GaAs substrates and then remove the substrate. However, using undoped GaP substrates, which are transparent to the infrared and red portions of the spectrum, thin structures of Ga1−xAlxAs with large external efficiencies can now be made.
Tumor Development after 3-Methylcholanthrene in Immunologically Deficient Athymic-Nude Mice (1974)

Athymic-nude (nu/nu) mice and normal (nu/+) mice showed no differences in either latent period or incidence of local sarcomas or lung adenomas within 120 days after administration of 3-methylcholanthrene at birth. However, nu/nu mice were incapable of rejecting allogeneic skin grafts for the duration of the experiment. These results argue against an active role of thymus-dependent immunity as a surveillance mechanism preventing tumor development.
Activation of Guinea Pig Peritoneal Macrophages by Platelet Activating Factor (PAF) and Its Agonists1 (1985)

The platelet activating factor (PAF: 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine) and its analogs were examined to determine their effects on guinea pig peritoneal macrophages. PAF activated macrophages, but its effect on macrophages was much weaker than that observed on platelets: the concentration required for 50% maximum activation was 8.5 X 10(-6) M for macrophages and 2.9 X 10(-10) M for platelets. Three PAF agonists, 1-O-octadecyl-2-O-(N,N-dimethylcarbamoyl)-glycero-3-phosphocholine (Compound I), 1-O-octadecyl-2-acetamido-2-deoxy-glycero-3-phosphocholine (Compound II), and 1-O-octadecyl-2-O-methyl-glycero-3-phosphocholine (Compound III), showed higher activity in stimulating macrophage function than PAF. The abilities of these non-metabolizable PAF agonists to activate macrophage paralleled their relative potency to induce platelet activation. The sn-3 enantiomers of PAF and Compound III exhibited activity, while the sn-1 did not. By comparing the activities of derivatives of Compound III, it was shown that the long-chain alkyl-ether group in the glycerol-1 position, a relatively small size of the substituent on the hydroxy group at the sn-2 position, and the choline moiety in the glycerol-3 position must play critical roles in the process of macrophage activation. A specific PAF antagonist, CV3988, which inhibits PAF-induced platelet activation and hypotension, inhibited the activation of macrophages caused by PAF and its agonists.(ABSTRACT TRUNCATED AT 250 WORDS)
Packed Column SFC (1995)

Packed Column SFC is the third title to be published in this series and has been produced as a result of the dramatic re-emergence, in the last three years, of packed column instrumentation. This has led to a redefinition of the technique and an urgent need for a practical guide that deals with its subtleties. This book fulfils that need and deals exclusively with packed column SFC. It places the emphasis on understanding the underlying chemistry in order to perform rapid, systematic optimizations and provides many practical tips to help the new user avoid problems unique to SFC. It also proposes a detailed scheme for method development and provides lists of prioritized guidelines. The book clears up some of the confusion that surrounds the analytical use of supercritical fluids and assists the user in understanding the power and utility of this technique. Detailed chapters cover the most promising new application areas for packed column SFC, which are often overlooked in the mainstream chromatography literature. Like the other books in this popular series, Packed Column SFC will prove an invaluable guide and is essential reading for graduates, postgraduates and researchers with interests in pharmaceuticals, agricultural chemistry, small polar drug molecules, chiral analysis, environmental chemistry, and chromatography/instrumentation.
Research on heterocyclic compounds. XIII. Synthesis of 4,5‐dihydro‐5‐oxo‐3‐isoxazoleacetic acid and related compounds (1983)

Abstract Some new 4,5‐dihydro‐5‐oxoisoxazole derivatives were synthesized as part of a study to prepare potential antiinflammatory agents. The reaction of the diethyl ester of 3‐oxopentanedioic acid with hydroxylamine afforded the 3‐hydroxyimino derivative, which was then cyclized to the title compound. This reacted with diazomethane to give a couple of isomeric methyl derivatives, namely methyl 2,5‐dihydro‐2‐methyl‐5‐oxo‐3‐isoxazoleacetate and methyl 5‐methoxy‐3‐isoxazoleacetate. Reaction of these compounds with ammonia gave the corresponding acetamides. All compounds were characterized by elemental analysis, uv, ir, and 1 H‐nmr spectra.
LDHT: Locality-aware Distributed Hash Tables (2008)

As the substrate of structured peer-to-peer systems, distributed hash table (DHT) plays a key role in P2P routing infrastructures. Traditional DHT does not consider the location of the nodes for the assignment of identifiers, which will result in high end-to-end latency on DHT-based overlay networks. In this paper, we propose a design of locality-aware DHT called LDHT, which exploits network locality on DHT-based systems. Instead of assigning uniform random node identifiers in traditional DHT, nodes in LDHT are assigned locality-aware identifiers according to their autonomous system numbers (ASNs). As a result, each node will have more nearby neighbors than faraway neighbors in the overlay. We evaluate the performance of LDHT on different kinds of typical DHT protocols and on various topologies. The results show that LDHT improves the traditional DHT protocols a lot in terms of end-to-end latency, without introducing additional overhead. It is indicated that LDHT is fit for different kinds of DHT protocols and can work effectively on all structured P2P systems including Chord, Symphony and Kademlia.
Charge Transport Mechanisms in the Transfer of Latent Electrostatic Images to Dielectric Surfaces (1962)

The transfer of electrostatic charge patterns from one surface to another requires movement of electrical charges across very small air gaps. Gaseous electronics alone is not sufficient to account for charge transport across extremely small gaps. The concept of field emission is introduced as a supplementary mechanism of charge transport and as a source of primary electrons.
Which is better at a high power reactive power compensation system, high PWM frequency or multiple connection? (2002)

In general, higher PWM frequency gives better performance at small or medium capacity inverters. This paper deals with the comparisons between two systems, SB and MB at a multi-10 MVA GTO power converter for reactive power compensation from the viewpoints of desired switching frequency and converter connections. SB is a single bridge system consisting of a three-phase bridge power converter unit and a transformer and its PWM frequency varies from 450 Hz to 1800 Hz. The line frequency is 50 Hz. 1 MB or 3 MB is a multiple bridge system consisting of plural single- or three-phase power converter units and transformers. Two kinds of systems using different transformer windings are considered. Type A uses conventional but complicated zigzag windings and type B simple star and delta windings. The switching frequencies are chosen the lowest, 50 Hz for 1 MB and 150 Hz for 3 MB. The evaluated items are harmonic distortion, power loss, GTO utilization factor and control response. A simulation study shows that MB is superior to SB in any case, even in the case of severe line faults where very quick response is requested. A new control strategy is adopted for obtaining quick response. Type B system has almost the same characteristics as type A system and can easily conquer the DC magnetization of the power converter transformers that may be encountered at a line voltage disturbance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Minimum and Full Fluidization Velocity for Alumina Used in the Aluminum Smelter (2011)

Fluidization is an engineering unit operation that occurs when a fluid (liquid or gas) ascends through a bed of particles, and these particles get a velocity of minimum fluidization V mf enough to stay in suspension, but without carrying them in the ascending flow. As from this moment the powder behaves as liquid at boiling point, hence the term “fluidization”. This operation is widely used in the aluminum smelter processes, for gas dry scrubbing (mass transfer) and in a modern plant for continuous alumina pot feeding (particles' momentum transfer). The understanding of the alumina fluoride rheology is of vital importance in the design of fluidized beds for gas treatment and fluidized pipelines for pot feeding. This paper shows the results of the experimental and theoretical values of the minimum and full fluidization velocities for the alumina fluoride used to project the state of the art round non-metallic air-fluidized conveyor of multiples outlets.