gebhart/patrepeval huggingface dataset:
Quantum Chemical Study of the Mechanism of Action of Vitamin K Carboxylase (VKC). IV. Intermediates and Transition States (2007)

We studied proposed steps for the enzymatic formation of gamma-carboxyglutamic acid by density functional theory (DFT) quantum chemistry. Our results for one potentially feasible mechanism show that a vitamin K alkoxide intermediate can abstract a proton from glutamic acid at the gamma-carbon to form a carbanion and vitamin K epoxide. The hydrated carbanion can then react with CO2 to form gamma-carboxyglutamic acid. Computations at the B3LYP/6-311G** level were used to determine the intermediates and transition states for the overall process. The activation free energy for the gas-phase path is 22 kcal/mol, with the rate-limiting step for the reaction being the attack of the carbanion on CO2. Additional solvation studies, however, indicate that the formation of the carbanion step can be competitive with the CO2 attack step in high-dielectric systems. We relate these computations to the entire vitamin K cycle in the blood coagulation cascade, which is essential for viability of vertebrates.
Controlling traffic with radio (2001)

The author reviews the role of radio frequencies in the control of traffic and pedestrians. He discusses active control of traffic junctions based on vehicle actuated demands; implying a requirement for vehicles approaching junctions or waiting at junctions to be detected, and for that detection event to be notified to the junction controller. It is also desirable to know the direction of an approaching vehicle. The great advantage of this approach is that the junction control system can generate a sequence for the light signals which should optimise the prevailing traffic flow. Detectors use a wide range of frequencies within the electromagnetic spectrum, ranging from visible light range down to tens of kHz. Within the radio frequency range, and subject to the operating frequency used, traffic detection can be effected using either below ground or above-ground antennas. The author describes both of these systems and the frequencies used for the latter. The operation and implementation of these systems is then discussed.
Vertical Alignment of Liquid Crytals on Polydimethylsiloxane Thin Films (2011)

Studies on the use of polydimethylsiloxane to align liquid crystals have been carried out. The thin films prepared using the silicon-based elastomer, with a pretty low surface free energy, are found to be capable of vertically aligning liquid crystals. The pretilt angle of calamitic liquid crystals sandwiched between thin silicon elastomer films was virtually 90 degrees. Liquid crystal devices consisting of elastomer alignment layers can operate in the in-plane-switch mode. Full text: PDF References: E. Lueder, Liquid Crystal Displays-Addressing Schemes and Electro-Optical Effects (Chichester, John Wiley & Sons 2001) J. Glueck, (PhD Thesis, University of Stuttgart 1995) DisplaySearch, Quarterly Wide Viewing Angle Technology Report (2010) [DirectLink] C.M. Knobler, "A microstamp of approval", Nature 369, 15 (1994) [CrossRef] D. Qin, Y. Xia, G.M. Whitesides, "Rapid prototyping of complex structures with feature sizes larger than 20 ?m", Adv. Mater. 8, 917 (1996) [CrossRef] M. Geissler, Y. Xia, "Patterning: Principles and Some New Developments", Adv. Mater. 16, 1249 (2004) [CrossRef] Y.T. Kim, J.H. Hong, T.Y. Yoon, S.D. Lee, "Pixel-encapsulated flexible displays with a multifunctional elastomer substrate for self-aligning liquid crystals", Appl. Phys. Lett. 88, 263501 (2006) [CrossRef] D.K. Owens, R.C. Wendt, "Estimation of the surface free energy of polymers", J. Appl. Polym. Sci. 13, 1741 (1969) [CrossRef] W. Zheng, C. H. Lu, Y. Yeh, "Effects of Mechanical Rubbing on Surface Tension of Polyimide Thin Films", Jpn. J. Appl. Phys. 47, 1651 (2008) [CrossRef] L.T. Creagh, A.R. Kmetz, "Mechanism of Surface Alignment in Nematic Liquid Crystals", Mol. Cryst. Liq. Cryst. 24, 59 (1973) [CrossRef] F.J. Kahn, C.N. Tayor, H. Schonhorn, "Surface-produced alignment of liquid crystals", Proc. IEEE 61, 823 (1973) [CrossRef] W. Zheng, L. Yang, R.O.C. Patent, 200931140
Mechanical prediction of fracture aperture in layered rocks (2000)

Two types of opening‐mode fractures (joints) are commonly found in layered rocks. One is called unconfined because fracture heights are much less than the layer thickness and they behave like fractures in massive rocks. The other is called confined because the fractures terminate at the layer boundaries. We investigate the mechanical control on apertures in these systems using the theory of elasticity. An analytical solution demonstrates that the ratio of aperture to height (aspect ratio) of an unconfined fracture in a homogeneous, isotropic medium is linearly related to the average strain, the overburden stress, and the internal fluid pressure within the fracture. Numerical results based on of the finite element method (FEM) for an unconfined fracture in the central layer of a three‐layer model agree with the analytical result when the fractured layer and neighboring layers have the same elastic constants. The aspect ratio of the unconfined fracture is insensitive to the ratio of Young's modulus of the fractured layer to that of the neighboring layers and to the differences in Poisson's ratios. The FEM results for confined fractures show that their aspect ratio is linearly related to the average strain, the overburden stress, and the internal fluid pressure. However, the aspect ratio increases nonlinearly with increasing fracture spacing to layer thickness ratio because of the mechanical interaction between adjacent fractures. The interaction becomes insignificant when the spacing to layer thickness ratio is &gt; ∼ 6.0. The aspect ratio of confined fractures depends on the ratio of Young's modulus of the fractured layer to that of the neighboring layers. This dependence is significant when the fracture spacing to layer thickness ratio is &lt;1.3; otherwise, it is negligible. In all of these cases the aspect ratio of confined fractures is insensitive to variations in Poisson's ratios. Furthermore, the FEM results predict that fracture accommodated strain measured by the traditional scan line method may slightly overestimate the average normal strain when the spacing to layer thickness ratio is &lt; ∼ 1.0, and may slightly underestimate this strain for greater ratios.
Effects of Combined Shear and Thermal Forces on Destruction of <i>Microbacterium lacticum</i> (1999)

A twin-screw extruder and a rotational rheometer were used to generate shear forces in concentrated gelatin inoculated with a heat-resistant isolate of a vegetative bacterial species, Microbacterium lacticum. Shear forces in the extruder were mainly controlled by varying the water feed rate. The water content of the extrudates changed between 19 and 45% (wet weight basis). Higher shear forces generated at low water contents and the calculated die wall shear stress correlated strongly with bacterial destruction. No surviving microorganisms could be detected at the highest wall shear stress of 409 kPa, giving log reduction of 5.3 (minimum detection level, 2 x 10(4) CFU/sample). The mean residence time of the microorganism in the extruder was 49 to 58 s, and the maximum temperature measured in the end of the die was 73 degrees C. The D(75 degrees C) of the microorganism in gelatin at 65% water content was 20 min. It is concluded that the physical forces generated in the reverse screw element and the extruder die rather than heat played a major part in cell destruction. In a rotational rheometer, after shearing of a mix of microorganisms with gelatin at 65% (wt/wt) moisture content for 4 min at a shear stress of 2.8 kPa and a temperature of 75 degrees C, the number of surviving microorganisms in the sheared sample was 5.2 x 10(6) CFU/g of sample compared with 1.4 x 10(8) CFU/g of sample in the nonsheared control. The relative effectiveness of physical forces in the killing of bacteria and destruction of starch granules is discussed.
Driving skill analysis using machine learning The full curve and curve segmented cases (2012)

Analysis of driving skill/driver state can be used in building driver support and infotainment systems that can be adapted to individual needs of a driver. In this paper we present a machine learning approach to analyzing driving maneuver skills of a driver that covers both longitudinal and lateral controls. The concept is to learn a driver model from sensor data that are related to driving environment, driving behavior and vehicle response. Once the model is built, driving skills of an unknown run can be classified automatically. In this paper, we demonstrate the feasibility of the proposed method for driving skill analysis based on a driving simulator experiment in a curve driving scene for both the full curve and curve segmented cases.
Multiple field strength <i>in vivo T</i><sub>1</sub> and <i>T</i><sub>2</sub> for cerebrospinal fluid protons (1986)

To estimate the feasibility of measuring in vivo CSF protein, oxygen, or other solutes through their effect on proton relaxation times, the T1 and T2 of CSF protons has been measured within the human lateral ventricles. T1 was measured at 6.25, 25.4, and 60.1 MHz with a two-point method. T2 was measured at 6.25 and 25.4 MHz using the CPMG sequence to acquire 8 echo images. The T1 was 4.3 s with no evidence of field dependence. The T2 was 2 s. Although these values approach those for water at the same temperature it is possible that the T1 is influenced by the normal oxygen concentration. Calculations based on the relaxivity of dissolved protein indicate that the use of these methods for the detection of elevated levels of CSF protein would be less sensitive than existing methods.
Dbl and the Rho GTPases Activate NFκB by IκB Kinase (IKK)-dependent and IKK-independent Pathways (2001)

Dbl is a guanine nucleotide exchange factor that activates the Rho family GTPases Cdc42, Rac, and Rho. Dbl and all three GTPases are strong activators of transcription factor NF kappa B, which has been shown to have an important role in Dbl-induced oncogenic transformation. Here we show that although Dbl activation of NF kappa B requires Cdc42, Rac, and Rho, the different GTPases activate NF kappa B by different mechanisms. Whereas Rac stimulates the activity of the I kappa B kinase IKK beta, Cdc42 and Rho activate NF kappa B without activating either IKK alpha or IKK beta. Like Dbl, Rac activation of IKK beta is mediated by the serine/threonine kinases NIK but not MEKK. This differs from Rac activation of the JNK pathway, which was previously shown to be mediated by MEKK. The pathway leading from Rho and Cdc42 to NF kappa B is more elusive, but our results suggest that it involves an IKK alpha/IKK beta-independent mechanism. Finally, we show that the signaling enzymes that mediate NF kappa B activation by Dbl and the Rho GTPases are also necessary for malignant transformation induced by oncogenic Dbl.
Recommendations for the Management of Patients With Unruptured Intracranial Aneurysms (2000)

HomeStrokeVol. 31, No. 11Recommendations for the Management of Patients With Unruptured Intracranial Aneurysms
Using Digital Classrooms to Conduct 4-H Club Meetings (2012)

Using computer technology and digital classrooms to conduct 4-H Club meetings is an efficient way to continue delivering quality 4-H programming during times of limited resources and staff. Nineteen Junior and Senior 4-H'ers participated in seven digital classroom workshops using the Wimba Classroom application. These digital classroom sessions were designed to improve Project Achievement development and increase competition scores. Eighteen of the nineteen 4-H participants increased Project Achievement scores by approximately 11%. Seven hours of travel time and 26 hours of instruction time were saved by utilizing digital classroom technology in a 3-month period.
<i>N</i>-Heterocyclic Carbene Functionalized Polymer for Reversible Fixation−Release of CO<sub>2</sub> (2009)

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTN-Heterocyclic Carbene Functionalized Polymer for Reversible Fixation−Release of CO2Hui Zhou, Wen-Zhen Zhang, Yi-Ming Wang, Jing-Ping Qu, and Xiao-Bing Lu*View Author Information State Key Laboratory of Fine Chemicals, Dalian University of Technology, 158 Zhongshan Road, Dalian 116012, China*Corresponding author. E-mail: [email protected]Cite this: Macromolecules 2009, 42, 15, 5419–5421Publication Date (Web):July 20, 2009Publication History Received21 May 2009Revised13 July 2009Published online20 July 2009Published inissue 11 August 2009https://pubs.acs.org/doi/10.1021/ma901109jhttps://doi.org/10.1021/ma901109jrapid-communicationACS PublicationsCopyright © 2009 American Chemical SocietyRequest reuse permissionsArticle Views3390Altmetric-Citations72LEARN 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-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Absorption,Adducts,Carbene compounds,Copolymers,Polymers Get e-Alerts
Randomized active atomicity violation detection in concurrent programs (2008)

Atomicity is an important specification that enables programmers to understand atomic blocks of code in a multi-threaded program as if they are sequential. This significantly simplifies the programmer's job to reason about correctness. Several modern multithreaded programming languages provide no built-in support to ensure atomicity; instead they rely on the fact that programmers would use locks properly in order to guarantee that atomic code blocks are indeed atomic. However, improper use of locks can sometimes fail to ensure atomicity. Therefore, we need tools that can check atomicity properties of lock-based code automatically.
A Negative-Working Alkaline Developable Photoresist Based on Calix[4]resorcinarene, a Cross-linker, and a Photoacid Generator (1997)

Abstract A negative working photoresist based on calix[4]resorcinarene, 4,4′-methylenebis[2,6-bis(hydroxymethyl)phenol] (MBHP) as a cross-linker, and a photoacid generator, diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS), has been developed. A clear negative pattern was obtained when it was exposed to 365 nm UV light and postbaked at 130 °C, followed by developing with a 0.5% aqueous tetramethylammonium hydroxide solution at room temperature.
Hardware aging-based software metering (2009)

Reliable and verifiable hardware, software and content usage metering (HSCM) are of primary importance for wide segments of e-commerce including intellectual property and digital rights management. We have developed the first HSCM technique that employs intrinsic aging properties of components in modern and pending integrated circuits (ICs) to create the first self-enforceable HSCM approach. There are variety of hardware aging techniques that range from electro-migration in wires to slow-down of crystal-based clocks. We focus on transistor aging due to negative bias temperature instability (NBTI) effects where the delay of gates increases proportionally to usage times. We address the problem of how we can measure the amount of time a particular licensed software (LS) is used by designing an aging circuitry and exposing it to the unique inputs associated with each LS. If a particular LS is used longer than specified, it automatically disables itself. Our novel HSCM technique uses a multi-stage optimization problem of computing the delays of gates, their aging degradation factors, and finally LS usage using convex programming. The experimental results show not just viability of the technique but also surprisingly high accuracy in the presence of measurement noise and imperfect aging models. HSCM can be used for many other business and engineering applications such as power minimization, software evaluation, and processor design.
A New Technique for Retarding Fading of Fluorescence: Dpx-Bme (1985)

The antioxidant beta-mercaptoethanol (BME) used in conjunction with the permanent mountant DPX (DPX-BME) retarded fluorescent fading of mithramycin, acridine orange and Hoechst 33258 stained chicken erythrocytes, each to a varying degree. The initial fluorescence of all dyes examined was more intense with DPX-BME than with DPX alone. Specimens mounted in DPX-BME showed strong fluorescence and excellent morphology; if kept in the dark, they could be stored indefinitely without deterioration. Retarding fading of fluorescence with DPX-BME faciliated quantitation of DNA using fluorescence cytophotometry.
Nonrandomness in protein sequences: evidence for a physically driven stage of evolution? (1994)

The sequences, or primary structures, of existing biopolymers--in particular, proteins--are believed to be a product of evolution. Are the sequences random? If not, what is the character of this nonrandomness? To explore the statistics of protein sequences, we use the idea of mapping the sequence onto the trajectory of a random walk, originally proposed by Peng et al. [Peng, C.-K., Buldyrev, S. V., Goldberger, A. L., Havlin, S., Sciortino, F., Simons, M. & Stanley, H. E. (1992) Nature (London) 356, 168-170] in their analysis of DNA sequences. Using three different mappings, corresponding to three basic physical interactions between amino acids, we found pronounced deviations from pure randomness, and these deviations seem directed toward minimization of the energy of the three-dimensional structure. We consider this result as evidence for a physically driven stage of evolution.
Mitochondrial and sarcolemmal Ca2+ transport reduce [Ca2+]i during caffeine contractures in rabbit cardiac myocytes. (1992)

1. Contraction and intracellular Ca2+ (Ca2+i) transients were measured in isolated rabbit ventricular myocytes during twitches and contractures induced by rapid application of 10 mM-caffeine. 2. The amplitude of caffeine-induced contractures and the accompanying Ca2+i transients were larger than during normal twitches and also declined more slowly. This may be because only a fraction of sarcoplasmic reticulum (SR) Ca2+ is released during a normal twitch, or because of a temporal overlap of SR Ca2+ release and uptake during the twitch. 3. When a caffeine contracture was initiated in Na(+)-free, Ca(2+)-free medium (to prevent sarcolemmal Na(+)-Ca2+ exchange) the contracture and Ca2+i transient were larger and decreased much more slowly. Thus, Ca2+ extrusion via Na(+)-Ca2+ exchange may limit the amplitude of caffeine-induced contractures. 4. Relaxation half-time (t1/2) for the twitch (0.17 +/- 0.03 s) was increased to 0.54 +/- 0.07 s for caffeine contractures in control solution and 8.8 +/- 1 s for caffeine-induced contractures in Na(+)-free, Ca(2+)-free solution. These results confirm that the SR Ca2+ pump and Na(+)-Ca2+ exchange are the predominant mechanisms for cytoplasmic Ca2+ removal during relaxation. However slower mechanisms can still reduce intracellular [Ca2+]. 5. Relaxation of caffeine contractures in Na(+)-free solution was further slowed when (a) mitochondrial Ca2+ uptake was inhibited with the oxidative phosphorylation uncoupler, FCCP (t1/2 = 19.7 +/- 3.2 s), or (b) the sarcolemmal Ca(2+)-ATPase pumping ability was depressed by a large transmembrane [Ca2+] gradient (t1/2 = 27.5 +/- 6.9 s). 6. When the four Ca2+ transport systems were simultaneously inhibited (i.e. SR Ca2+ pump, Na(+)-Ca2+ exchange, mitochondrial Ca2+ uptake and sarcolemmal Ca2+ pump), relaxation was practically abolished, but the cell could recover quickly when Na+ was reintroduced and caffeine removed. 7. We conclude that, under our experimental conditions, the sarcolemmal Ca2+ pump and mitochondria are approximately 37- and 50-fold slower than the Na(+)-Ca2+ exchange at removing Ca2+ from the cytoplasm. Additionally, the SR Ca2+ pump is about 3-4 times faster than Na(+)-Ca2+ exchange.
Package-chip co-design to increase flip-chip C4 reliability (2011)

The magnitude of the I/O requirements for modern ICs continues to increase due to the growing complexity and size of ICs. The large I/O count found on most ICs have forced most designers to use flip-chip packaging instead of wire bonded packaging. Unfortunately, the solder bumps in flip-chip packages are susceptible to failure, especially in the presence of high temperatures which can cause large stresses and strains leading to mechanical failure of the bump. In this paper, we present a simplified stress/strain/fatigue model that can be used during floorplanning to optimize for package reliability. We also demonstrate a quadratic C4 bump placement method that can be used during floorplanning to increase C4 bump reliability. Our experimental results show that this co-optimization can increase the lifetime of C4 bumps by about 47× with only a modest 3% increase in HPWL wirelength.
Angiotensin (1-7) re-establishes impulse conduction in cardiac muscle during ischaemia-reperfusion. The role of the sodium pump (2004)

Ang (1-7) activates the sodium pump, hyperpolarises the heart cell and re-establishes the impulse conduction during ischaemia/reperfusion. These effects of Ang (1-7), and the increment of cardiac refractoriness, provide an explanation for the reduced incidence of arrhythmias during ischaemia/reperfusion in the presence of Ang (1-7).
Advances in Biochemistry and Microbial Production of Squalene and Its Derivatives (2016)

Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically, squalene is used not only as a precursor in the synthesis of complex secondary metabolites such as sterols, hormones, and vitamins, but also as a carbon source in aerobic and anaerobic fermentation in microorganisms. Owing to the increasing roles of squalene as an antioxidant, anticancer, and anti-inflammatory agent, the demand for this chemical is highly urgent. As a result, with the exception of traditional methods of the isolation of squalene from animals (shark liver oil) and plants, biotechnological methods using microorganisms as producers have afforded increased yield and productivity, but a reduction in progress. In this paper, we first review the biosynthetic routes of squalene and its typical derivatives, particularly the squalene synthase route. Second, typical biotechnological methods for the enhanced production of squalene using microbial cell factories are summarized and classified. Finally, the outline and discussion of the novel trend in the production of squalene with several updated events to 2015 are presented.