Voting strategy for artifact reduction in digital breast tomosynthesis.

PubMed

Wu, Tao; Moore, Richard H; Kopans, Daniel B

2006-07-01

Artifacts are observed in digital breast tomosynthesis (DBT) reconstructions due to the small number of projections and the narrow angular range that are typically employed in tomosynthesis imaging. In this work, we investigate the reconstruction artifacts that are caused by high-attenuation features in breast and develop several artifact reduction methods based on a "voting strategy." The voting strategy identifies the projection(s) that would introduce artifacts to a voxel and rejects the projection(s) when reconstructing the voxel. Four approaches to the voting strategy were compared, including projection segmentation, maximum contribution deduction, one-step classification, and iterative classification. The projection segmentation method, based on segmentation of high-attenuation features from the projections, effectively reduces artifacts caused by metal and large calcifications that can be reliably detected and segmented from projections. The other three methods are based on the observation that contributions from artifact-inducing projections have higher value than those from normal projections. These methods attempt to identify the projection(s) that would cause artifacts by comparing contributions from different projections. Among the three methods, the iterative classification method provides the best artifact reduction; however, it can generate many false positive classifications that degrade the image quality. The maximum contribution deduction method and one-step classification method both reduce artifacts well from small calcifications, although the performance of artifact reduction is slightly better with the one-step classification. The combination of one-step classification and projection segmentation removes artifacts from both large and small calcifications.

Comparison of the Screening Tests for Gestational Diabetes Mellitus between "One-Step" and "Two-Step" Methods among Thai Pregnant Women.

PubMed

Luewan, Suchaya; Bootchaingam, Phenphan; Tongsong, Theera

2018-01-01

To compare the prevalence and pregnancy outcomes of GDM between those screened by the "one-step" (75 gm GTT) and "two-step" (100 gm GTT) methods. A prospective study was conducted on singleton pregnancies at low or average risk of GDM. All were screened between 24 and 28 weeks, using the one-step or two-step method based on patients' preference. The primary outcome was prevalence of GDM, and secondary outcomes included birthweight, gestational age, rates of preterm birth, small/large-for-gestational age, low Apgar scores, cesarean section, and pregnancy-induced hypertension. A total of 648 women were screened: 278 in the one-step group and 370 in the two-step group. The prevalence of GDM was significantly higher in the one-step group; 32.0% versus 10.3%. Baseline characteristics and pregnancy outcomes in both groups were comparable. However, mean birthweight was significantly higher among pregnancies with GDM diagnosed by the two-step approach (3204 ± 555 versus 3009 ± 666 g; p =0.022). Likewise, the rate of large-for-date tended to be higher in the two-step group, but was not significant. The one-step approach is associated with very high prevalence of GDM among Thai population, without clear evidence of better outcomes. Thus, this approach may not be appropriate for screening in a busy antenatal care clinic like our setting or other centers in developing countries.

A comparative study of one-step and two-step approaches for MAPbI3 perovskite layer and its influence on the performance of mesoscopic perovskite solar cell

NASA Astrophysics Data System (ADS)

Wang, Minhuan; Feng, Yulin; Bian, Jiming; Liu, Hongzhu; Shi, Yantao

2018-01-01

The mesoscopic perovskite solar cells (M-PSCs) were synthesized with MAPbI3 perovskite layers as light harvesters, which were grown with one-step and two-step solution process, respectively. A comparative study was performed through the quantitative correlation of resulting device performance and the crystalline quality of perovskite layers. Comparing with the one-step counterpart, a pronounced improvement in the steady-state power conversion efficiencies (PCEs) by 56.86% was achieved with two-step process, which was mainly resulted from the significant enhancement in fill factor (FF) from 48% to 77% without sacrificing the open circuit voltage (Voc) and short circuit current (Jsc). The enhanced FF was attributed to the reduced non-radiative recombination channels due to the better crystalline quality and larger grain size with the two-step processed perovskite layer. Moreover, the superiority of two-step over one-step process was demonstrated with rather good reproducibility.

SU-F-J-66: Anatomy Deformation Based Comparison Between One-Step and Two-Step Optimization for Online ART

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Z; Yu, G; Qin, S

Purpose: This study investigated that how the quality of adapted plan was affected by inter-fractional anatomy deformation by using one-step and two-step optimization for on line adaptive radiotherapy (ART) procedure. Methods: 10 lung carcinoma patients were chosen randomly to produce IMRT plan by one-step and two-step algorithms respectively, and the prescribed dose was set as 60 Gy on the planning target volume (PTV) for all patients. To simulate inter-fractional target deformation, four specific cases were created by systematic anatomy variation; including target superior shift 0.5 cm, 0.3cm contraction, 0.3 cm expansion and 45-degree rotation. Based on these four anatomy deformation,more » adapted plan, regenerated plan and non-adapted plan were created to evaluate quality of adaptation. Adapted plans were generated automatically by using one-step and two-step algorithms respectively to optimize original plans, and regenerated plans were manually created by experience physicists. Non-adapted plans were produced by recalculating the dose distribution based on corresponding original plans. The deviations among these three plans were statistically analyzed by paired T-test. Results: In PTV superior shift case, adapted plans had significantly better PTV coverage by using two-step algorithm compared with one-step one, and meanwhile there was a significant difference of V95 by comparison with adapted and non-adapted plans (p=0.0025). In target contraction deformation, with almost same PTV coverage, the total lung received lower dose using one-step algorithm than two-step algorithm (p=0.0143,0.0126 for V20, Dmean respectively). In other two deformation cases, there were no significant differences observed by both two optimized algorithms. Conclusion: In geometry deformation such as target contraction, with comparable PTV coverage, one-step algorithm gave better OAR sparing than two-step algorithm. Reversely, the adaptation by using two-step algorithm had higher efficiency and accuracy as target occurred position displacement. We want to thank Dr. Lei Xing and Dr. Yong Yang in the Stanford University School of Medicine for this work. This work was jointly supported by NSFC (61471226), Natural Science Foundation for Distinguished Young Scholars of Shandong Province (JQ201516), and China Postdoctoral Science Foundation (2015T80739, 2014M551949).« less

Effect of Saliva on the Tensile Bond Strength of Different Generation Adhesive Systems: An In-Vitro Study.

PubMed

Gupta, Nimisha; Tripathi, Abhay Mani; Saha, Sonali; Dhinsa, Kavita; Garg, Aarti

2015-07-01

Newer development of bonding agents have gained a better understanding of factors affecting adhesion of interface between composite and dentin surface to improve longevity of restorations. The present study evaluated the influence of salivary contamination on the tensile bond strength of different generation adhesive systems (two-step etch-and-rinse, two-step self-etch and one-step self-etch) during different bonding stages to dentin where isolation is not maintained. Superficial dentin surfaces of 90 extracted human molars were randomly divided into three study Groups (Group A: Two-step etch-and-rinse adhesive system; Group B: Two-step self-etch adhesive system and Group C: One-step self-etch adhesive system) according to the different generation of adhesives used. According to treatment conditions in different bonding steps, each Group was further divided into three Subgroups containing ten teeth in each. After adhesive application, resin composite blocks were built on dentin and light cured subsequently. The teeth were then stored in water for 24 hours before sending for testing of tensile bond strength by Universal Testing Machine. The collected data were then statistically analysed using one-way ANOVA and Tukey HSD test. One-step self-etch adhesive system revealed maximum mean tensile bond strength followed in descending order by Two-step self-etch adhesive system and Two-step etch-and-rinse adhesive system both in uncontaminated and saliva contaminated conditions respectively. Unlike One-step self-etch adhesive system, saliva contamination could reduce tensile bond strength of the two-step self-etch and two-step etch-and-rinse adhesive system. Furthermore, the step of bonding procedures and the type of adhesive seems to be effective on the bond strength of adhesives contaminated with saliva.

Electrical Conductivity through a Single Atomic Step Measured with the Proximity-Induced Superconducting Pair Correlation

DOE PAGES

Kim, Howon; Lin, Shi -Zeng; Graf, Matthias J.; ...

2016-09-08

Local disordered nanostructures in an atomically thick metallic layer on a semiconducting substrate play significant and decisive roles in transport properties of two-dimensional (2D) conductive systems. We measured the electrical conductivity through a step of monoatomic height in a truly microscopic manner by using as a signal the superconducting pair correlation induced by the proximity effect. The transport property across a step of a one-monolayer Pb surface metallic phase, formed on a Si(111) substrate, was evaluated by inducing the pair correlation around the local defect and measuring its response, i.e., the reduced density of states at the Fermi energy usingmore » scanning tunneling microscopy. We found that the step resistance has a significant contribution to the total resistance on a nominally flat surface. Our study also revealed that steps in the 2D metallic layer terminate the propagation of the pair correlation. Furthermore, superconductivity is enhanced between the first surface step and the superconductor–normal-metal interface by reflectionless tunneling when the step is located within a coherence length.« less

Electrical Conductivity through a Single Atomic Step Measured with the Proximity-Induced Superconducting Pair Correlation.

PubMed

Kim, Howon; Lin, Shi-Zeng; Graf, Matthias J; Miyata, Yoshinori; Nagai, Yuki; Kato, Takeo; Hasegawa, Yukio

2016-09-09

Local disordered nanostructures in an atomically thick metallic layer on a semiconducting substrate play significant and decisive roles in transport properties of two-dimensional (2D) conductive systems. We measured the electrical conductivity through a step of monoatomic height in a truly microscopic manner by using as a signal the superconducting pair correlation induced by the proximity effect. The transport property across a step of a one-monolayer Pb surface metallic phase, formed on a Si(111) substrate, was evaluated by inducing the pair correlation around the local defect and measuring its response, i.e., the reduced density of states at the Fermi energy using scanning tunneling microscopy. We found that the step resistance has a significant contribution to the total resistance on a nominally flat surface. Our study also revealed that steps in the 2D metallic layer terminate the propagation of the pair correlation. Superconductivity is enhanced between the first surface step and the superconductor-normal-metal interface by reflectionless tunneling when the step is located within a coherence length.

How does social support relieve depression among flood victims? The contribution of feelings of safety, self-disclosure, and negative cognition.

PubMed

Zhen, Rui; Quan, Lijuan; Zhou, Xiao

2018-03-15

Depression is one of the most common post-trauma symptoms that can be alleivated by social support. The purpose of this study was to examine the multiple mediating effects of social support on depression via feelings of safety, disclosure, and negative cognition. One hundred and eighty-seven flood victims in Wuhu City, an area affected most severely by a flood during July 2016, were selected to complete a self-report questionnaire package. Social support has four indirect negative effects on depression, including a one-step indirect path to self-disclosure, 2 two-step paths from feelings of safety to self-disclosure, and from self-disclosure to negative cognition about self, and a three-step indirect path from feelings of life safety via self-disclosure to negative self-cognition. All variables were measured using self-report scales. Social support may relieve depression in flood victims by inducing feelings of safety and self-disclosure, and by relieving negative cognition. Copyright © 2018 Elsevier B.V. All rights reserved.

Formation of aqueous-phase sulfate during the haze period in China: Kinetics and atmospheric implications

NASA Astrophysics Data System (ADS)

Zhang, Haijie; Chen, Shilu; Zhong, Jie; Zhang, Shaowen; Zhang, Yunhong; Zhang, Xiuhui; Li, Zesheng; Zeng, Xiao Cheng

2018-03-01

Sulfate is one of the most important components in the aerosol due to its key role in air pollution and global climate change. Recent work has suggested that reactive nitrogen chemistry in aqueous water can explain the missing source of sulfate in the aqueous water. Herein, we have mapped out the energy profile of the oxidization process of SO2 leading from NO2 and two feasible three-step mechanisms have been proposed. For the oxidation of HOSO2- and HSO3- by the dissolved NO2 in weakly acidic and neutral aerosol (pH ≤ 7), the main contribution to the missing sulfate production comes from the oxidation of HOSO2-. The whole process is a self-sustaining process. For the oxidation of SO32- in alkaline aerosol (pH > 7), the third step - decomposition step of H2O or hydrolysis of SO3 step which are two parallel processes are the rate-limiting steps. The present results are of avail to better understand the missing source of sulfate in the aerosol and hence may lead to better science-based solutions for resolving the severe haze problems in China.

A quantum dynamical study of the He++2He-->He2++He reaction

NASA Astrophysics Data System (ADS)

Xie, Junkai; Poirier, Bill; Gellene, Gregory I.

2003-11-01

The temperature dependent rate of the He++2He→He2++He three-body association reaction is studied using two complementary quantum dynamical models. Model I presumes a two-step, reverse Lindemann mechanism, where the intermediate energized complex, He2+*, is interpreted as the rotational resonance states of He2+. The energy and width of these resonances are determined via "exact" quantum calculation using highly accurate potential-energy curves. Model II uses an alternate quantum rate expression as the thermal average of the cumulative recombination probability, N(E). This microcanonical quantity is computed approximately, over the He2+ space only, with the third-body interaction modeled using a special type of absorbing potential. Because Model II implicitly incorporates both the two-step reverse Lindemann mechanism, and a one-step, reverse collision induced dissociation mechanism, the relative importance of the two formation mechanisms can be estimated by a comparison of the Model I and Model II results. For T<300 K, the reaction is found to be dominated by the two-step mechanism, and a formation rate in good agreement with the available experimental results is obtained with essentially no adjustable parameters in the theory. Interestingly, a nonmonotonic He2+ formation rate is observed, with a maximum identified near 25 K. This maximum is associated with just two reaction intermediate resonance states, the lowest energy states that can contribute significantly to the formation kinetics.

Control Circuit For Two Stepping Motors

NASA Technical Reports Server (NTRS)

Ratliff, Roger; Rehmann, Kenneth; Backus, Charles

1990-01-01

Control circuit operates two independent stepping motors, one at a time. Provides following operating features: After selected motor stepped to chosen position, power turned off to reduce dissipation; Includes two up/down counters that remember at which one of eight steps each motor set. For selected motor, step indicated by illumination of one of eight light-emitting diodes (LED's) in ring; Selected motor advanced one step at time or repeatedly at rate controlled; Motor current - 30 mA at 90 degree positions, 60 mA at 45 degree positions - indicated by high or low intensity of LED that serves as motor-current monitor; Power-on reset feature provides trouble-free starts; To maintain synchronism between control circuit and motors, stepping of counters inhibited when motor power turned off.

Instrumental resolution as a function of scattering angle and wavelength as exemplified for the POWGEN instrument

PubMed Central

Jacobs, Philipp; Houben, Andreas; Schweika, Werner; Tchougréeff, Andrei L.; Dronskowski, Richard

2017-01-01

The method of angular- and wavelength-dispersive (e.g. two-dimensional) Rietveld refinement is a new and emerging tool for the analysis of neutron diffraction data measured at time-of-flight instruments with large area detectors. Following the approach for one-dimensional refinements (using either scattering angle or time of flight), the first step at each beam time cycle is the calibration of the instrument including the determination of instrumental contributions to the peak shape variation to be expected for diffraction patterns measured by the users. The aim of this work is to provide the users with calibration files and – for the later Rietveld refinement of the measured data – with an instrumental resolution file (IRF). This article will elaborate on the necessary steps to generate such an IRF for the angular- and wavelength-dispersive case, exemplified for the POWGEN instrument. A dataset measured on a standard diamond sample is used to extract the profile function in the two-dimensional case. It is found that the variation of reflection width with 2θ and λ can be expressed by the standard equation used for evaluating the instrumental resolution, which yields a substantially more fundamental approach to the parameterization of the instrumental contribution to the peak shape. Geometrical considerations of the POWGEN instrument and sample effects lead to values for Δθ, Δt and ΔL that yield a very good match to the extracted FWHM values. In a final step the refinement results are compared with the one-dimensional, i.e. diffraction-focused, case. PMID:28656041

A Time Domain Analysis of Gust-Cascade Interaction Noise

NASA Technical Reports Server (NTRS)

Nallasamy, M.; Hixon, R.; Sawyer, S. D.; Dyson, R. W.

2003-01-01

The gust response of a 2 D cascade is studied by solving the full nonlinear Euler equations employing higher order accurate spatial differencing and time stepping techniques. The solutions exhibit the exponential decay of the two circumferential mode orders of the cutoff blade passing frequency (BPF) tone and propagation of one circumferential mode order at 2BPF, as would be expected for the flow configuration considered. Two frequency excitations indicate that the interaction between the frequencies and the self interaction contribute to the amplitude of the propagating mode.

Semisynthesis of Intact Complex-Type Triantennary Oligosaccharides from a Biantennary Oligosaccharide Isolated from a Natural Source by Selective Chemical and Enzymatic Glycosylation.

PubMed

Maki, Yuta; Okamoto, Ryo; Izumi, Masayuki; Murase, Takefumi; Kajihara, Yasuhiro

2016-03-16

Attachment of oligosaccharides to proteins is a major post-translational modification. Chemical syntheses of oligosaccharides have contributed to clarifying the functions of these oligosaccharides. However, syntheses of oligosaccharide-linked proteins are still challenging because of their inherent complicated structures, including diverse di- to tetra-antennary forms. We report a highly efficient strategy to access the representative two types of triantennary oligosaccharides through only 9- or 10-step chemical conversions from a biantennary oligosaccharide, which can be isolated in exceptionally homogeneous form from egg yolk. Four benzylidene acetals were successfully introduced to the terminal two galactosides and two core mannosides of the biantennary asialononasaccharide bearing 24 hydroxy groups, followed by protection of the remaining hydroxy groups with acetyl groups. Selective removal of one of the benzylidene acetals gave two types of suitably protected glycosyl acceptors. Glycosylation toward the individual acceptors with protected Gal-β-1,4-GlcN thioglycoside and subsequent deprotection steps successfully yielded two types of complex-type triantennary oligosaccharides.

The Effects of Dissipation and Coarse Grid Resolution for Multigrid in Flow Problems

NASA Technical Reports Server (NTRS)

Eliasson, Peter; Engquist, Bjoern

1996-01-01

The objective of this paper is to investigate the effects of the numerical dissipation and the resolution of the solution on coarser grids for multigrid with the Euler equation approximations. The convergence is accomplished by multi-stage explicit time-stepping to steady state accelerated by FAS multigrid. A theoretical investigation is carried out for linear hyperbolic equations in one and two dimensions. The spectra reveals that for stability and hence robustness of spatial discretizations with a small amount of numerical dissipation the grid transfer operators have to be accurate enough and the smoother of low temporal accuracy. Numerical results give grid independent convergence in one dimension. For two-dimensional problems with a small amount of numerical dissipation, however, only a few grid levels contribute to an increased speed of convergence. This is explained by the small numerical dissipation leading to dispersion. Increasing the mesh density and hence making the problem over resolved increases the number of mesh levels contributing to an increased speed of convergence. If the steady state equations are elliptic, all grid levels contribute to the convergence regardless of the mesh density.

Incidence, risk factors, and pregnancy outcomes of gestational diabetes mellitus using one-step versus two-step diagnostic approaches: A population-based cohort study in Isfahan, Iran.

PubMed

Hosseini, Elham; Janghorbani, Mohsen; Aminorroaya, Ashraf

2018-06-01

To study the incidence, risk factors, and pregnancy outcomes associated with gestational diabetes mellitus (GDM) diagnosed with one-step and two-step screening approaches. 1000 pregnant women who were eligible and consented to participate underwent fasting plasma glucose testing at the first prenatal visit (6-14 weeks). The women free from GDM or overt diabetes were screened at 24-28 weeks using the 50-g glucose challenge test (GCT) followed by 100-g, 3-h oral glucose tolerance test (OGTT) (two-step method). Regardless of the GCT result, all women underwent a 75-g, 2-h OGTT within one-week interval (one-step method). GDM incidence using the one-step and two-step methods was 9.3% (95% CI: 7.4-11.2) and 4.2% (95% CI: 2.9-5.5). GDM significantly increased the risk of macrosomia, gestational hypertension, preeclampsia, and cesarean section and older age and family history of diabetes significantly increased the risk of developing GDM in both approaches. In two-step method, higher pre-pregnancy body mass index and lower physical activity during pregnancy along with higher earlier cesarean section also increased significantly the risk of developing GDM. Despite a higher incidence of GDM using the one-step approach, more risk factors for and a stronger effect of GDM on adverse pregnancy outcomes were found when using the two-step approach. Longer follow-up of women with and without GDM may change the results using both approaches. Copyright © 2018 Elsevier B.V. All rights reserved.

Redo Laparoscopic Gastric Bypass: One-Step or Two-Step Procedure?

PubMed

Theunissen, Caroline M J; Guelinckx, Nele; Maring, John K; Langenhoff, Barbara S

2016-11-01

The adjustable gastric band (AGB) is a bariatric procedure that used to be widely performed. However, AGB failure-signifying band-related complications or unsatisfactory weight loss, resulting in revision surgery (redo operations)-frequently occurs. Often this entails a conversion to a laparoscopic Roux-en-Y gastric bypass (LRYGB). This can be performed as a one-step or two-step (separate band removal) procedure. Data were collected from patients operated from 2012 to 2014 in a single bariatric centre. We compared 107 redo LRYGB after AGB failure with 1020 primary LRYGB. An analysis was performed of the one-step vs. two-step redo procedures. All redo procedures were performed by experienced bariatric surgeons. No difference in major complication rate was seen (2.8 vs. 2.3 %, p = 0.73) between redo and primary LRYGB, and overall complication severity for redos was low (mainly Clavien-Dindo 1 or 2). Weight loss results were comparable for primary and redo procedures. The one-step and two-step redos were comparable regarding complication rates and readmissions. The operating time for the one-step redo LRYGB was 136 vs. 107.5 min for the two-step (median, p < 0.001), excluding the operating time of separate AGB removal (mean 61 min, range 36-110). Removal of a failed AGB and LRYGB in a one-step procedure is safe when performed by experienced bariatric surgeons. However, when erosion or perforation of the AGB occurs, we advise caution and would perform the redo LRYGB as a two-step procedure. Equal weights can be achieved at 1 year post redo LRYGB as after primary LRYGB procedures.

Designing and Introducing Ethical Dilemmas into Computer-Based Business Simulations

ERIC Educational Resources Information Center

Schumann, Paul L.; Scott, Timothy W.; Anderson, Philip H.

2006-01-01

This article makes two contributions to the teaching of business ethics literature. First, it describes the steps involved in developing effective ethical dilemmas to incorporate into a computer-based business simulation. Second, it illustrates these steps by presenting two ethical dilemmas that an instructor can incorporate into any business…

Efficiency and Safety of One-Step Procedure Combined Laparoscopic Cholecystectomy and Eretrograde Cholangiopancreatography for Treatment of Cholecysto-Choledocholithiasis: A Randomized Controlled Trial.

PubMed

Liu, Zhiyi; Zhang, Luyao; Liu, Yanling; Gu, Yang; Sun, Tieliang

2017-11-01

We aimed to evaluate the efficiency and safety of one-step procedure combined endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy (LC) for treatment of patients with cholecysto-choledocholithiasis. A prospective randomized study was performed on 63 consecutive cholecysto-choledocholithiasis patients during 2008 and 2011. The efficiency and safety of one-step procedure was assessed by comparing the two-step LC with ERCP + endoscopic sphincterotomy (EST). Outcomes including intraoperative features, postoperative features (length of stay and postoperative complications) were evaluated. One- or two-step procedure of LC with ERCP + EST was successfully performed in all patients, and common bile duct stones were completely removed. Statistical analyses showed that length of stay and pulmonary infection rate were significantly lower in the test group compared with that in the control group (P < 0.05), whereas no statistical difference in other outcomes was found between the two groups (all P > 0.05). The one-step procedure of LC with ERCP + EST is superior to the two-step procedure for treatment of patients with cholecysto-choledocholithiasis regarding to the reduced hospital stay and inhibited occurrence of pulmonary infections. Compared with two-step procedure, one-step procedure of LC with ERCP + EST may be a superior option for cholecysto-choledocholithiasis patients treatment regarding to hospital stay and pulmonary infections.

Systematic assessment of different solvents for the extraction of drugs of abuse and pharmaceuticals from an authentic hair pool.

PubMed

Madry, Milena M; Kraemer, Thomas; Baumgartner, Markus R

2018-01-01

Hair analysis has been established as a prevalent tool for retrospective drug monitoring. In this study, different extraction solvents for the determination of drugs of abuse and pharmaceuticals in hair were evaluated for their efficiency. A pool of authentic hair from drug users was used for extraction experiments. Hair was pulverized and extracted in triplicate with seven different solvents in a one- or two-step extraction. Three one- (methanol, acetonitrile, and acetonitrile/water) and four two-step extractions (methanol two-fold, methanol and methanol/acetonitrile/formate buffer, methanol and methanol/formate buffer, and methanol and methanol/hydrochloric acid) were tested under accurately equal experimental conditions. The extracts were directly analyzed by liquid chromatography-tandem mass spectrometry for opiates/opioids, stimulants, ketamine, selected benzodiazepines, antidepressants, antipsychotics, and antihistamines using deuterated internal standards. For most analytes, a two-step extraction with methanol did not significantly improve the yield compared to a one-step extraction with methanol. Extraction with acetonitrile alone was least efficient for most analytes. Extraction yields of acetonitrile/water, methanol and methanol/acetonitrile/formate buffer, and methanol and methanol/formate buffer were significantly higher compared to methanol. Highest efficiencies were obtained by a two-step extraction with methanol and methanol/hydrochloric acid, particularly for morphine, 6-monoacetylmorphine, codeine, 6-acetylcodeine, MDMA, zopiclone, zolpidem, amitriptyline, nortriptyline, citalopram, and doxylamine. For some analytes (e.g., tramadol, fluoxetine, sertraline), all extraction solvents, except for acetonitrile, were comparably efficient. There was no significant correlation between extraction efficiency with an acidic solvent and the pka or log P of the analyte. However, there was a significant trend for the extraction efficiency with acetonitrile to the log P of the analyte. The study demonstrates that the choice of extraction solvent has a strong impact on hair analysis outcomes. Therefore, validation protocols should include the evaluation of extraction efficiency of drugs by using authentic rather than spiked hair. Different extraction procedures may contribute to the scatter of quantitative results in inter-laboratory comparisons. Harmonization of extraction protocols is recommended, when interpretation is based on same cut-off levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Regularized two-step brain activity reconstruction from spatiotemporal EEG data

NASA Astrophysics Data System (ADS)

Alecu, Teodor I.; Voloshynovskiy, Sviatoslav; Pun, Thierry

2004-10-01

We are aiming at using EEG source localization in the framework of a Brain Computer Interface project. We propose here a new reconstruction procedure, targeting source (or equivalently mental task) differentiation. EEG data can be thought of as a collection of time continuous streams from sparse locations. The measured electric potential on one electrode is the result of the superposition of synchronized synaptic activity from sources in all the brain volume. Consequently, the EEG inverse problem is a highly underdetermined (and ill-posed) problem. Moreover, each source contribution is linear with respect to its amplitude but non-linear with respect to its localization and orientation. In order to overcome these drawbacks we propose a novel two-step inversion procedure. The solution is based on a double scale division of the solution space. The first step uses a coarse discretization and has the sole purpose of globally identifying the active regions, via a sparse approximation algorithm. The second step is applied only on the retained regions and makes use of a fine discretization of the space, aiming at detailing the brain activity. The local configuration of sources is recovered using an iterative stochastic estimator with adaptive joint minimum energy and directional consistency constraints.

Effects of frequency shifts and visual gender information on vowel category judgments

NASA Astrophysics Data System (ADS)

Glidden, Catherine; Assmann, Peter F.

2003-10-01

Visual morphing techniques were used together with a high-quality vocoder to study the audiovisual contribution of talker gender to the identification of frequency-shifted vowels. A nine-step continuum ranging from ``bit'' to ``bet'' was constructed from natural recorded syllables spoken by an adult female talker. Upward and downward frequency shifts in spectral envelope (scale factors of 0.85 and 1.0) were applied in combination with shifts in fundamental frequency, F0 (scale factors of 0.5 and 1.0). Downward frequency shifts generally resulted in malelike voices whereas upward shifts were perceived as femalelike. Two separate nine-step visual continua from ``bit'' to ``bet'' were also constructed, one from a male face and the other a female face, each producing the end-point words. Each step along the two visual continua was paired with the corresponding step on the acoustic continuum, creating natural audiovisual utterances. Category boundary shifts were found for both acoustic cues (F0 and formant frequency shifts) and visual cues (visual gender). The visual gender effect was larger when acoustic and visual information were matched appropriately. These results suggest that visual information provided by the speech signal plays an important supplemental role in talker normalization.

Solution of elliptic partial differential equations by fast Poisson solvers using a local relaxation factor. 2: Two-step method

NASA Technical Reports Server (NTRS)

Chang, S. C.

1986-01-01

A two-step semidirect procedure is developed to accelerate the one-step procedure described in NASA TP-2529. For a set of constant coefficient model problems, the acceleration factor increases from 1 to 2 as the one-step procedure convergence rate decreases from + infinity to 0. It is also shown numerically that the two-step procedure can substantially accelerate the convergence of the numerical solution of many partial differential equations (PDE's) with variable coefficients.

Comparison of one- and two-photon optical beam-induced current imaging

NASA Astrophysics Data System (ADS)

Xu, Chris; Denk, Winfried

1999-08-01

Optical beam induced current (OBIC) imaging through the backside of integrated circuits was investigated in the wavelength λ region from 1.15 to 1.26 μm. With a subpicosecond excitation source and approximately 1 mW at the sample, the two-photon contribution to the generated photocurrent dominates at λ=1.25 μm but becomes negligible for λ<1.18 μm. One-photon- (1P-) and two-photon- (2P-) OBIC images are very different. In the 1P case a strong contribution by scattered light to the carrier generation leads to an edge enhancement effect that is entirely missing when 2P excitation dominates. 2P-OBIC images often show supply-voltage dependent intensity steps that are much sharper than the optical resolution permits. The advantages of 2P-OBIC lie in the spatial confinement of the free carrier generation, a more relevant contrast mechanism, and the promise of a substantial increase in spatial resolution because of the quadratic intensity dependence and the possibility of using silicon solid immersion lenses, which could eventually provide resolution sufficient for circuits made by deep UV lithography.

Steady-State Density Functional Theory for Finite Bias Conductances.

PubMed

Stefanucci, G; Kurth, S

2015-12-09

In the framework of density functional theory, a formalism to describe electronic transport in the steady state is proposed which uses the density on the junction and the steady current as basic variables. We prove that, in a finite window around zero bias, there is a one-to-one map between the basic variables and both local potential on as well as bias across the junction. The resulting Kohn-Sham system features two exchange-correlation (xc) potentials, a local xc potential, and an xc contribution to the bias. For weakly coupled junctions the xc potentials exhibit steps in the density-current plane which are shown to be crucial to describe the Coulomb blockade diamonds. At small currents these steps emerge as the equilibrium xc discontinuity bifurcates. The formalism is applied to a model benzene junction, finding perfect agreement with the orthodox theory of Coulomb blockade.

48 CFR 14.503-2 - Step two.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Step two. 14.503-2 Section... AND CONTRACT TYPES SEALED BIDDING Two-Step Sealed Bidding 14.503-2 Step two. (a) Sealed bidding... submitting acceptable technical proposals in step one; (2) Include the provision prescribed in 14.201-6(t...

Are women positive for the One Step but negative for the Two Step screening tests for gestational diabetes at higher risk for adverse outcomes?

PubMed

Caissutti, Claudia; Khalifeh, Adeeb; Saccone, Gabriele; Berghella, Vincenzo

2018-02-01

The aim of this study was to evaluate if women meeting criteria for gestational diabetes mellitus (GDM) by the One Step test as per International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria but not by other less strict criteria have adverse pregnancy outcomes compared with GDM-negative controls. The primary outcome was the incidence of macrosomia, defined as birthweight > 4000 g. Electronic databases were searched from their inception until May 2017. All studies identifying pregnant women negative at the Two Step test, but positive at the One Step test for IADPSG criteria were included. We excluded studies that randomized women to the One Step vs. the Two Step tests; studies that compared different criteria within the same screening method; randomized studies comparing treatments for GDM; and studies comparing incidence of GDM in women doing the One Step test vs. the Two Step test. Eight retrospective cohort studies, including 29 983 women, were included. Five study groups and four control groups were identified. The heterogeneity between the studies was high. Gestational hypertension, preeclampsia and large for gestational age, as well as in some analyses cesarean delivery, macrosomia and preterm birth, were significantly more frequent, and small for gestational age in some analyses significantly less frequent, in women GDM-positive by the One Step, but not the Two Step. Women meeting criteria for GDM by IADPSG criteria but not by other less strict criteria have an increased risk of adverse pregnancy outcomes such as gestational hypertension, preeclampsia and large for gestational age, compared with GDM-negative controls. Based on these findings, and evidence from other studies that treatment decreases these adverse outcomes, we suggest screening for GDM using the One Step IADPSG criteria. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

Two Steps Forward, One Step Backward: Must This Be the Future of Diversity?

ERIC Educational Resources Information Center

Butler, Johnnella E.

2013-01-01

Johnnella Butler writes here that the title of this article "Two Steps Forward, One Step Backward," expresses the "wicked problem" of diversity as a concrete goal in higher education. The concept of the "wicked problem," is a term coined in the late 1960s by social planners. Consulting Wikipedia, as so many of our…

One Step Forward, One Step Beck: A Contribution to the Ongoing Conceptual Debate in Youth Studies

ERIC Educational Resources Information Center

Roberts, Steven

2012-01-01

In a time of rapid and unprecedented social change, the concepts we use to make sense of the ways in which young people understand and interact with the world are very much under the microscope. Some researchers argue that we need to reinvigorate our conceptual repertoire, while others argue that our theoretical tool box still has the capacity to…

Virtual Allergist

MedlinePlus

... One Choose A Body Area: Eyes Step Two Select A Symptom: Itchy eyes Step Three Possible Issues: ... conjunctivitis Mold allergy Pet allergy Nose Step Two Select A Symptom: Nasal congestion Step Three Possible Issues: ...

Elastic scattering of 8He on 4He and 4 n system

NASA Astrophysics Data System (ADS)

Wolski, R.; Sidorchuk, S. I.; Ter-Akopian, G. M.; Fomichev, A. S.; Rodin, A. M.; Stepantsov, S. V.; Mittig, W.; Roussel-Chomaz, P.; Savajols, H.; Alamanos, N.; Auger, F.; Lapoux, V.; Raabe, R.; Tchuvil'sky, Yu. M.; Rusek, K.

2003-07-01

Elastic scattering of a 26A MeV beam of 8He on a gaseous helium target has been studied. In spite of efforts made for the observation of backward angle enhancement only upper limits could be obtained for the elastic scattering cross section at backward angles. The angular distribution of 8He nuclei scattered to CM 20°-80° was was analyzed in terms of a phenomenological Optical Model. Possible contributions from transfer reactions were estimated. The DWBA calculations indicate that the two step 2n transfer is more important than the one step 4n transfer. The transfer reaction d( 8He, 6Li)4n is discussed in terms of possible tests of a four-neutron system.

Possible mechanism for the onset of step-bunching instabilities during the epitaxy of single-species crystalline films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cermelli, Paolo; Jabbour, Michel E.; Department of Mathematics, University of Kentucky, Lexington, Kentucky 40506-0027

A thermodynamically consistent continuum theory for single-species, step-flow epitaxy that extends the classical Burton-Cabrera-Frank (BCF) framework is derived from basic considerations. In particular, an expression for the step chemical potential is obtained that contains two energetic contributions--one from the adjacent terraces in the form of the jump in the adatom grand canonical potential and the other from the monolayer of crystallized adatoms that underlies the upper terrace in the form of the nominal bulk chemical potential--thus generalizing the classical Gibbs-Thomson relation to the dynamic, dissipative setting of step-flow growth. The linear stability analysis of the resulting quasistatic free-boundary problem formore » an infinite train of equidistant rectilinear steps yields explicit--i.e., analytical--criteria for the onset of step bunching in terms of the basic physical and geometric parameters of the theory. It is found that, in contrast with the predictions of the classical BCF model, both in the absence as well as in the presence of desorption, a growth regime exists for which step bunching occurs, except possibly in the dilute limit where the train is always stable to step bunching. In the present framework, the onset of one-dimensional instabilities is directly attributed to the energetic influence on the migrating steps of the adjacent terraces. Hence the theory provides a ''minimalist'' alternative to existing theories of step bunching and should be relevant to, e.g., molecular beam epitaxy of GaAs where the equilibrium adatom density is shown by Tersoff, Johnson, and Orr [Phys. Rev. B 78, 282 (1997)] to be extremely high.« less

Comparison of IMRT planning with two-step and one-step optimization: a strategy for improving therapeutic gain and reducing the integral dose

NASA Astrophysics Data System (ADS)

Abate, A.; Pressello, M. C.; Benassi, M.; Strigari, L.

2009-12-01

The aim of this study was to evaluate the effectiveness and efficiency in inverse IMRT planning of one-step optimization with the step-and-shoot (SS) technique as compared to traditional two-step optimization using the sliding windows (SW) technique. The Pinnacle IMRT TPS allows both one-step and two-step approaches. The same beam setup for five head-and-neck tumor patients and dose-volume constraints were applied for all optimization methods. Two-step plans were produced converting the ideal fluence with or without a smoothing filter into the SW sequence. One-step plans, based on direct machine parameter optimization (DMPO), had the maximum number of segments per beam set at 8, 10, 12, producing a directly deliverable sequence. Moreover, the plans were generated whether a split-beam was used or not. Total monitor units (MUs), overall treatment time, cost function and dose-volume histograms (DVHs) were estimated for each plan. PTV conformality and homogeneity indexes and normal tissue complication probability (NTCP) that are the basis for improving therapeutic gain, as well as non-tumor integral dose (NTID), were evaluated. A two-sided t-test was used to compare quantitative variables. All plans showed similar target coverage. Compared to two-step SW optimization, the DMPO-SS plans resulted in lower MUs (20%), NTID (4%) as well as NTCP values. Differences of about 15-20% in the treatment delivery time were registered. DMPO generates less complex plans with identical PTV coverage, providing lower NTCP and NTID, which is expected to reduce the risk of secondary cancer. It is an effective and efficient method and, if available, it should be favored over the two-step IMRT planning.

[Effect of two-step sintering method on properties of zirconia ceramic].

PubMed

Huang, Hui; Wei, Bin; Zhang, Fu-Qiang; Sun, Jing; Gao, Lian

2008-04-01

To study the influence of two-step sintering method on the sintering property, mechanical properties and microstructure of zirconia ceramic. The nano-size zirconia powder were compacted and divided into two groups, one group for one-step sintering method, another group for two-step sintering method. All samples sintered at different temperature. The relative density, three-bend strength, HV hardness, fracture toughness and microstructure of sintered block were investigated. Two-step sintering method influenced the sintering property and mechanical properties of zirconia ceramic. The maximal relative density was 98.49% at 900 degrees C/1,450 degrees C sintering temperature. There were significant difference of mechanical properties between one-step sintering and two-step sintering, the three-bend strength and fracture toughness declined, hardness increased at two-step sintering. The three-bend strength, HV hardness and fracture toughness reached to maximum value as 1,059.08 MPa +/- 75.24 MPa, 1,377.00 MPa +/- 16.37 MPa and 5.92 MPa x m1/2 +/- 0.37 MPa x m1/2 at 900 degrees C/1,450 degrees C sintering temperature respectively. Microscopy revealed the relationship between the porosity and shapes of grains was correlated to strength of the zirconia ceramics. Despite of the two-step sintering method influences the properties of zirconia, it also is a promising esthetic all-ceramic dental material.

Solution of elliptic PDEs by fast Poisson solvers using a local relaxation factor

NASA Technical Reports Server (NTRS)

Chang, Sin-Chung

1986-01-01

A large class of two- and three-dimensional, nonseparable elliptic partial differential equations (PDEs) is presently solved by means of novel one-step (D'Yakanov-Gunn) and two-step (accelerated one-step) iterative procedures, using a local, discrete Fourier analysis. In addition to being easily implemented and applicable to a variety of boundary conditions, these procedures are found to be computationally efficient on the basis of the results of numerical comparison with other established methods, which lack the present one's: (1) insensitivity to grid cell size and aspect ratio, and (2) ease of convergence rate estimation by means of the coefficient of the PDE being solved. The two-step procedure is numerically demonstrated to outperform the one-step procedure in the case of PDEs with variable coefficients.

Accuracy of Multiple Pour Cast from Various Elastomer Impression Methods

PubMed Central

Saad Toman, Majed; Ali Al-Shahrani, Abdullah; Ali Al-Qarni, Abdullah

2016-01-01

The accurate duplicate cast obtained from a single impression reduces the profession clinical time, patient inconvenience, and extra material cost. The stainless steel working cast model assembly consisting of two abutments and one pontic area was fabricated. Two sets of six each custom aluminum trays were fabricated, with five mm spacer and two mm spacer. The impression methods evaluated during the study were additional silicone putty reline (two steps), heavy-light body (one step), monophase (one step), and polyether (one step). Type IV gypsum casts were poured at the interval of one hour, 12 hours, 24 hours, and 48 hours. The resultant cast was measured with traveling microscope for the comparative dimensional accuracy. The data obtained were subjected to Analysis of Variance test at significance level <0.05. The die obtained from two-step putty reline impression techniques had the percentage of variation for the height −0.36 to −0.97%, while diameter was increased by 0.40–0.90%. The values for one-step heavy-light body impression dies, additional silicone monophase impressions, and polyether were −0.73 to −1.21%, −1.34%, and −1.46% for the height and 0.50–0.80%, 1.20%, and −1.30% for the width, respectively. PMID:28096815

Comparison of different statistical methods for estimation of extreme sea levels with wave set-up contribution

NASA Astrophysics Data System (ADS)

Kergadallan, Xavier; Bernardara, Pietro; Benoit, Michel; Andreewsky, Marc; Weiss, Jérôme

2013-04-01

Estimating the probability of occurrence of extreme sea levels is a central issue for the protection of the coast. Return periods of sea level with wave set-up contribution are estimated here in one site : Cherbourg in France in the English Channel. The methodology follows two steps : the first one is computation of joint probability of simultaneous wave height and still sea level, the second one is interpretation of that joint probabilities to assess a sea level for a given return period. Two different approaches were evaluated to compute joint probability of simultaneous wave height and still sea level : the first one is multivariate extreme values distributions of logistic type in which all components of the variables become large simultaneously, the second one is conditional approach for multivariate extreme values in which only one component of the variables have to be large. Two different methods were applied to estimate sea level with wave set-up contribution for a given return period : Monte-Carlo simulation in which estimation is more accurate but needs higher calculation time and classical ocean engineering design contours of type inverse-FORM in which the method is simpler and allows more complex estimation of wave setup part (wave propagation to the coast for example). We compare results from the two different approaches with the two different methods. To be able to use both Monte-Carlo simulation and design contours methods, wave setup is estimated with an simple empirical formula. We show advantages of the conditional approach compared to the multivariate extreme values approach when extreme sea-level occurs when either surge or wave height is large. We discuss the validity of the ocean engineering design contours method which is an alternative when computation of sea levels is too complex to use Monte-Carlo simulation method.

The effect of adopting the IADPSG screening guidelines on the risk profile and outcomes of the gestational diabetes population.

PubMed

March, Melissa I; Modest, Anna M; Ralston, Steven J; Hacker, Michele R; Gupta, Munish; Brown, Florence M

2016-01-01

To compare characteristics and outcomes of women diagnosed with gestational diabetes mellitus (GDM) by the newer one-step glucose tolerance test and those diagnosed with the traditional two-step method. This was a retrospective cohort study of women with GDM who delivered in 2010-2011. Data are reported as proportion or median (interquartile range) and were compared using a Chi-square, Fisher's exact or Wilcoxon rank sum test based on data type. Of 235 women with GDM, 55.7% were diagnosed using the two-step method and 44.3% with the one-step method. The groups had similar demographics and GDM risk factors. The two-step method group was diagnosed with GDM one week later [27.0 (24.0-29.0) weeks versus 26.0 (24.0-28.0 weeks); p = 0.13]. The groups had similar median weight gain per week before diagnosis. After diagnosis, women in the one-step method group had significantly higher median weight gain per week [0.67 pounds/week (0.31-1.0) versus 0.56 pounds/week (0.15-0.89); p = 0.047]. In the one-step method group more women had suspected macrosomia (11.7% versus 5.3%, p = 0.07) and more neonates had a birth weight >4000 g (13.6% versus 7.5%, p = 0.13); however, these differences were not statistically significant. Other pregnancy and neonatal complications were similar. Women diagnosed with the one-step method gained more weight per week after GDM diagnosis and had a non-statistically significant increased risk for suspected macrosomia. Our data suggest the one-step method identifies women with at least equally high risk as the two-step method.

United States Medical Licensing Examination and American Board of Pediatrics Certification Examination Results: Does the Residency Program Contribute to Trainee Achievement.

PubMed

Welch, Thomas R; Olson, Brad G; Nelsen, Elizabeth; Beck Dallaghan, Gary L; Kennedy, Gloria A; Botash, Ann

2017-09-01

To determine whether training site or prior examinee performance on the US Medical Licensing Examination (USMLE) step 1 and step 2 might predict pass rates on the American Board of Pediatrics (ABP) certifying examination. Data from graduates of pediatric residency programs completing the ABP certifying examination between 2009 and 2013 were obtained. For each, results of the initial ABP certifying examination were obtained, as well as results on National Board of Medical Examiners (NBME) step 1 and step 2 examinations. Hierarchical linear modeling was used to nest first-time ABP results within training programs to isolate program contribution to ABP results while controlling for USMLE step 1 and step 2 scores. Stepwise linear regression was then used to determine which of these examinations was a better predictor of ABP results. A total of 1110 graduates of 15 programs had complete testing results and were subject to analysis. Mean ABP scores for these programs ranged from 186.13 to 214.32. The hierarchical linear model suggested that the interaction of step 1 and 2 scores predicted ABP performance (F[1,1007.70] = 6.44, P = .011). By conducting a multilevel model by training program, both USMLE step examinations predicted first-time ABP results (b = .002, t = 2.54, P = .011). Linear regression analyses indicated that step 2 results were a better predictor of ABP performance than step 1 or a combination of the two USMLE scores. Performance on the USMLE examinations, especially step 2, predicts performance on the ABP certifying examination. The contribution of training site to ABP performance was statistically significant, though contributed modestly to the effect compared with prior USMLE scores. Copyright © 2017 Elsevier Inc. All rights reserved.

Objectively measured physical activity level during a physical education class: a pilot study with Swedish youth.

PubMed

Raustorp, Anders; Boldemann, Cecilia; Johansson, Maria; Mårtensson, Fredrika

2010-01-01

The aim of this study is to advance our knowledge of the contribution of a typical physical education (PE) class to children's daily physical activity. The pilot project is a part of a survey study comprising 11 fourth grader classes (250 pupils). One class of 19 pupils (9 girls) participated in the pilot study. Daily step counts were measured by Yamax pedometers during four consecutive weekdays. During PE class, the participants wore a second pedometer and an Actigraph GT1M accelerometer. The total average step count during PE class was 2512, average 74 steps/min. The counts for the whole day were 16668, and 19 steps/min respectively. The total share of moderate-vigorous physical activity (MVPA) of the PE class was 50.4% (52.5% and 48.3% for boys and girls respectively). There was an inverse correlation between daily mean step count and contribution of PE class step to daily mean step (r = -0.64, p = .003). The contribution of PE class to MVPA was in high in both boys and girls. Considering the suggested independent role of physical fitness for cardiovascular health in children, the PE class must be seen as an important health factor, especially for otherwise inactive children.

Toward a conceptual approach for assessing risks from chemical mixtures and other stressors to coastal ecosystem services.

PubMed

Syberg, Kristian; Backhaus, Thomas; Banta, Gary; Bruce, Peter; Gustavsson, Mikael; Munns, Wayne R; Rämö, Robert; Selck, Henriette; Gunnarsson, Jonas S

2017-03-01

Growth of human populations and increased human activity, particularly in coastal areas, increase pressure on coastal ecosystems and the ecosystem services (ES) they provide. As a means toward being able to assess the impact of multiple stressors on ES, in the present study we propose an 8-step conceptual approach for assessing effects of chemical mixtures and other stressors on ES in coastal areas: step A, identify the relevant problems and policy aims; step B, identify temporal and spatial boundaries; step C, identify relevant ES; step D, identify relevant stressors (e.g., chemicals); step E, translate impacts into ES units; step F, assess cumulative risk in ES units; step G, rank stressors based on their contribution to adverse effects on ES; and step H, implement regulation and management as appropriate and necessary. Two illustrative case studies (Swedish coastal waters and a coastal lagoon in Costa Rica) are provided; one focuses on chemicals that affect human food supply and the other addresses pesticide runoff and trade-offs among ES. The 2 cases are used to highlight challenges of such risk assessments, including use of standardized versus ES-relevant test species, data completeness, and trade-offs among ES. Lessons learned from the 2 case studies are discussed in relation to environmental risk assessment and management of chemical mixtures. Integr Environ Assess Manag 2017;13:376-386. © 2016 SETAC. © 2016 SETAC.

Shapiro steps for skyrmion motion on a washboard potential with longitudinal and transverse ac drives

DOE PAGES

Reichhardt, Charles; Reichhardt, Cynthia Jane

2015-12-28

In this work, we numerically study the behavior of two-dimensional skyrmions in the presence of a quasi-one-dimensional sinusoidal substrate under the influence of externally applied dc and ac drives. In the overdamped limit, when both dc and ac drives are aligned in the longitudinal direction parallel to the direction of the substrate modulation, the velocity-force curves exhibit classic Shapiro step features when the frequency of the ac drive matches the washboard frequency that is dynamically generated by the motion of the skyrmions over the substrate, similar to previous observations in superconducting vortex systems. In the case of skyrmions, the additionalmore » contribution to the skyrmion motion from a nondissipative Magnus force shifts the location of the locking steps to higher dc drives, and we find that the skyrmions move at an angle with respect to the direction of the dc drive. For a longitudinal dc drive and a perpendicular or transverse ac drive, the overdamped system exhibits no Shapiro steps; however, when a finite Magnus force is present, we find pronounced transverse Shapiro steps along with complex two-dimensional periodic orbits of the skyrmions in the phase-locked regimes. Both the longitudinal and transverse ac drives produce locking steps whose widths oscillate with increasing ac drive amplitude. We examine the role of collective skyrmion interactions and find that additional fractional locking steps occur for both longitudinal and transverse ac drives. Finally, at higher skyrmion densities, the system undergoes a series of dynamical order-disorder transitions, with the skyrmions forming a moving solid on the phase locking steps and a fluctuating dynamical liquid in regimes between the steps.« less

High efficient perovskite solar cell material CH3NH3PbI3: Synthesis of films and their characterization

NASA Astrophysics Data System (ADS)

Bera, Amrita Mandal; Wargulski, Dan Ralf; Unold, Thomas

2018-04-01

Hybrid organometal perovskites have been emerged as promising solar cell material and have exhibited solar cell efficiency more than 20%. Thin films of Methylammonium lead iodide CH3NH3PbI3 perovskite materials have been synthesized by two different (one step and two steps) methods and their morphological properties have been studied by scanning electron microscopy and optical microscope imaging. The morphology of the perovskite layer is one of the most important parameters which affect solar cell efficiency. The morphology of the films revealed that two steps method provides better surface coverage than the one step method. However, the grain sizes were smaller in case of two steps method. The films prepared by two steps methods on different substrates revealed that the grain size also depend on the substrate where an increase of the grain size was found from glass substrate to FTO with TiO2 blocking layer to FTO without any change in the surface coverage area. Present study reveals that an improved quality of films can be obtained by two steps method by an optimization of synthesis processes.

Limit theorems for Lévy walks in d dimensions: rare and bulk fluctuations

NASA Astrophysics Data System (ADS)

Fouxon, Itzhak; Denisov, Sergey; Zaburdaev, Vasily; Barkai, Eli

2017-04-01

We consider super-diffusive Lévy walks in d≥slant 2 dimensions when the duration of a single step, i.e. a ballistic motion performed by a walker, is governed by a power-law tailed distribution of infinite variance and finite mean. We demonstrate that the probability density function (PDF) of the coordinate of the random walker has two different scaling limits at large times. One limit describes the bulk of the PDF. It is the d-dimensional generalization of the one-dimensional Lévy distribution and is the counterpart of the central limit theorem (CLT) for random walks with finite dispersion. In contrast with the one-dimensional Lévy distribution and the CLT this distribution does not have a universal shape. The PDF reflects anisotropy of the single-step statistics however large the time is. The other scaling limit, the so-called ‘infinite density’, describes the tail of the PDF which determines second (dispersion) and higher moments of the PDF. This limit repeats the angular structure of the PDF of velocity in one step. A typical realization of the walk consists of anomalous diffusive motion (described by anisotropic d-dimensional Lévy distribution) interspersed with long ballistic flights (described by infinite density). The long flights are rare but due to them the coordinate increases so much that their contribution determines the dispersion. We illustrate the concept by considering two types of Lévy walks, with isotropic and anisotropic distributions of velocities. Furthermore, we show that for isotropic but otherwise arbitrary velocity distributions the d-dimensional process can be reduced to a one-dimensional Lévy walk. We briefly discuss the consequences of non-universality for the d  >  1 dimensional fractional diffusion equation, in particular the non-uniqueness of the fractional Laplacian.

Employee Use of a Wireless Physical Activity Tracker Within Two Incentive Designs at One Company.

PubMed

Norman, Gregory J; Heltemes, Kevin J; Heck, Debi; Osmick, Mary Jane

2016-04-01

Physical activity provides numerous health benefits, including reducing risk factors that contribute to the leading causes of morbidity and mortality. Many employers offer incentives to employees to motivate engagement in wellness program activities. Two incentive designs to reward employees for achieving step goals were evaluated. This study used a retrospective design and the study population consisted of benefit-eligible employees at American Specialty Health ages 18 to 65 years who completed a health assessment and biometric screening during 2011 (N=396) or 2012 (N=500). A total of 320 employees participated in both years. During 2011, the incentive goal was 500,000 steps per quarter. By comparison, a 3-tier step goal plan was implemented in 2012 (ie, 400,000; 650,000; or 900,000 steps/quarter). The prevalence of participants in the step program was 64.7% in 2011 and 72.8% in 2012. The percentage of employees who reached at least 1 quarterly incentive increased from 36.3% in 2011 to 51.4% in 2012. Average steps/day was higher in 2012 (mean [M]=3573, standard deviation [SD]=3010) compared to the same employees in 2011 (M=2817, SD=2654) (P<.001). The findings suggest that a tiered incentive design may be an effective population approach to engage employees in physical activity. A multitier incentive design offers participants choices for goal setting and may help shape behavior toward what may be perceived as a difficult goal to achieve. (Population Health Management 2016;19:88-94).

Kinetic analysis of overlapping multistep thermal decomposition comprising exothermic and endothermic processes: thermolysis of ammonium dinitramide.

PubMed

Muravyev, Nikita V; Koga, Nobuyoshi; Meerov, Dmitry B; Pivkina, Alla N

2017-01-25

This study focused on kinetic modeling of a specific type of multistep heterogeneous reaction comprising exothermic and endothermic reaction steps, as exemplified by the practical kinetic analysis of the experimental kinetic curves for the thermal decomposition of molten ammonium dinitramide (ADN). It is known that the thermal decomposition of ADN occurs as a consecutive two step mass-loss process comprising the decomposition of ADN and subsequent evaporation/decomposition of in situ generated ammonium nitrate. These reaction steps provide exothermic and endothermic contributions, respectively, to the overall thermal effect. The overall reaction process was deconvoluted into two reaction steps using simultaneously recorded thermogravimetry and differential scanning calorimetry (TG-DSC) curves by considering the different physical meanings of the kinetic data derived from TG and DSC by P value analysis. The kinetic data thus separated into exothermic and endothermic reaction steps were kinetically characterized using kinetic computation methods including isoconversional method, combined kinetic analysis, and master plot method. The overall kinetic behavior was reproduced as the sum of the kinetic equations for each reaction step considering the contributions to the rate data derived from TG and DSC. During reproduction of the kinetic behavior, the kinetic parameters and contributions of each reaction step were optimized using kinetic deconvolution analysis. As a result, the thermal decomposition of ADN was successfully modeled as partially overlapping exothermic and endothermic reaction steps. The logic of the kinetic modeling was critically examined, and the practical usefulness of phenomenological modeling for the thermal decomposition of ADN was illustrated to demonstrate the validity of the methodology and its applicability to similar complex reaction processes.

A two-step database search method improves sensitivity in peptide sequence matches for metaproteomics and proteogenomics studies.

PubMed

Jagtap, Pratik; Goslinga, Jill; Kooren, Joel A; McGowan, Thomas; Wroblewski, Matthew S; Seymour, Sean L; Griffin, Timothy J

2013-04-01

Large databases (>10(6) sequences) used in metaproteomic and proteogenomic studies present challenges in matching peptide sequences to MS/MS data using database-search programs. Most notably, strict filtering to avoid false-positive matches leads to more false negatives, thus constraining the number of peptide matches. To address this challenge, we developed a two-step method wherein matches derived from a primary search against a large database were used to create a smaller subset database. The second search was performed against a target-decoy version of this subset database merged with a host database. High confidence peptide sequence matches were then used to infer protein identities. Applying our two-step method for both metaproteomic and proteogenomic analysis resulted in twice the number of high confidence peptide sequence matches in each case, as compared to the conventional one-step method. The two-step method captured almost all of the same peptides matched by the one-step method, with a majority of the additional matches being false negatives from the one-step method. Furthermore, the two-step method improved results regardless of the database search program used. Our results show that our two-step method maximizes the peptide matching sensitivity for applications requiring large databases, especially valuable for proteogenomics and metaproteomics studies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A two step Bayesian approach for genomic prediction of breeding values.

PubMed

Shariati, Mohammad M; Sørensen, Peter; Janss, Luc

2012-05-21

In genomic models that assign an individual variance to each marker, the contribution of one marker to the posterior distribution of the marker variance is only one degree of freedom (df), which introduces many variance parameters with only little information per variance parameter. A better alternative could be to form clusters of markers with similar effects where markers in a cluster have a common variance. Therefore, the influence of each marker group of size p on the posterior distribution of the marker variances will be p df. The simulated data from the 15th QTL-MAS workshop were analyzed such that SNP markers were ranked based on their effects and markers with similar estimated effects were grouped together. In step 1, all markers with minor allele frequency more than 0.01 were included in a SNP-BLUP prediction model. In step 2, markers were ranked based on their estimated variance on the trait in step 1 and each 150 markers were assigned to one group with a common variance. In further analyses, subsets of 1500 and 450 markers with largest effects in step 2 were kept in the prediction model. Grouping markers outperformed SNP-BLUP model in terms of accuracy of predicted breeding values. However, the accuracies of predicted breeding values were lower than Bayesian methods with marker specific variances. Grouping markers is less flexible than allowing each marker to have a specific marker variance but, by grouping, the power to estimate marker variances increases. A prior knowledge of the genetic architecture of the trait is necessary for clustering markers and appropriate prior parameterization.

Clustering of amines and hydrazines in atmospheric nucleation

NASA Astrophysics Data System (ADS)

Li, Siyang; Qu, Kun; Zhao, Hailiang; Ding, Lei; Du, Lin

2016-06-01

It has been proved that the presence of amines in the atmosphere can enhance aerosol formation. Hydrazine (HD) and its substituted derivatives, monomethylhydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH), which are organic derivatives of amine and ammonia, are common trace atmospheric species that may contribute to the growth of nucleation clusters. The structures of the hydrazine and amine clusters containing one or two common nucleation molecules (ammonia, water, methanol and sulfuric acid) have been optimized using density functional theory (DFT) methods. The clusters growth mechanism has been explored from the thermochemistry by calculating the Gibbs free energies of adding an ammonia, water, methanol or sulfuric acid molecule step by step at room temperature, respectively. The results show that hydrazine and its derivatives could enhance heteromolecular homogeneous nucleation in the earth's atmosphere.

A New Two-Step Approach for Hands-On Teaching of Gene Technology: Effects on Students' Activities During Experimentation in an Outreach Gene Technology Lab

NASA Astrophysics Data System (ADS)

Scharfenberg, Franz-Josef; Bogner, Franz X.

2011-08-01

Emphasis on improving higher level biology education continues. A new two-step approach to the experimental phases within an outreach gene technology lab, derived from cognitive load theory, is presented. We compared our approach using a quasi-experimental design with the conventional one-step mode. The difference consisted of additional focused discussions combined with students writing down their ideas (step one) prior to starting any experimental procedure (step two). We monitored students' activities during the experimental phases by continuously videotaping 20 work groups within each approach ( N = 131). Subsequent classification of students' activities yielded 10 categories (with well-fitting intra- and inter-observer scores with respect to reliability). Based on the students' individual time budgets, we evaluated students' roles during experimentation from their prevalent activities (by independently using two cluster analysis methods). Independently of the approach, two common clusters emerged, which we labeled as `all-rounders' and as `passive students', and two clusters specific to each approach: `observers' as well as `high-experimenters' were identified only within the one-step approach whereas under the two-step conditions `managers' and `scribes' were identified. Potential changes in group-leadership style during experimentation are discussed, and conclusions for optimizing science teaching are drawn.

Bonding effectiveness of self-etch adhesives to dentin after 24 h water storage.

PubMed

Sarr, Mouhamed; Benoist, Fatou Leye; Bane, Khaly; Aidara, Adjaratou Wakha; Seck, Anta; Toure, Babacar

2018-01-01

This study evaluated the immediate bonding effectiveness of five self-etch adhesive systems bonded to dentin. The microtensile bond strength of five self-etch adhesives systems, including one two-step and four one-step self-etch adhesives to dentin, was measured. Human third molars had their superficial dentin surface exposed, after which a standardized smear layer was produced using a medium-grit diamond bur. The selected adhesives were applied according to their respective manufacturer's instructions for μTBS measurement after storage in water at 37°C for 24 h. The μTBS varied from 11.1 to 44.3 MPa; the highest bond strength was obtained with the two-step self-etch adhesive Clearfil SE Bond and the lowest with the one-step self-etch adhesive Adper Prompt L-Pop. Pretesting failures mainly occurring during sectioning with the slow-speed diamond saw were observed only with the one-step self-etch adhesive Adper Prompt L-Pop (4 out of 18). When bonded to dentin, the self-etch adhesives with simplified application procedures (one-step self-etch adhesives) still underperform as compared to the two-step self-etch adhesive Clearfil SE Bond.

Bonding effectiveness of self-etch adhesives to dentin after 24 h water storage

PubMed Central

Sarr, Mouhamed; Benoist, Fatou Leye; Bane, Khaly; Aidara, Adjaratou Wakha; Seck, Anta; Toure, Babacar

2018-01-01

Purpose: This study evaluated the immediate bonding effectiveness of five self-etch adhesive systems bonded to dentin. Materials and Methods: The microtensile bond strength of five self-etch adhesives systems, including one two-step and four one-step self-etch adhesives to dentin, was measured. Human third molars had their superficial dentin surface exposed, after which a standardized smear layer was produced using a medium-grit diamond bur. The selected adhesives were applied according to their respective manufacturer's instructions for μTBS measurement after storage in water at 37°C for 24 h. Results: The μTBS varied from 11.1 to 44.3 MPa; the highest bond strength was obtained with the two-step self-etch adhesive Clearfil SE Bond and the lowest with the one-step self-etch adhesive Adper Prompt L-Pop. Pretesting failures mainly occurring during sectioning with the slow-speed diamond saw were observed only with the one-step self-etch adhesive Adper Prompt L-Pop (4 out of 18). Conclusions: When bonded to dentin, the self-etch adhesives with simplified application procedures (one-step self-etch adhesives) still underperform as compared to the two-step self-etch adhesive Clearfil SE Bond. PMID:29674814

Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing.

PubMed

Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

2016-08-19

We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm(-1) K(-2)), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

Methods to approximate reliabilities in single-step genomic evaluation

USDA-ARS?s Scientific Manuscript database

Reliability of predictions from single-step genomic BLUP (ssGBLUP) can be calculated by inversion, but that is not feasible for large data sets. Two methods of approximating reliability were developed based on decomposition of a function of reliability into contributions from records, pedigrees, and...

Context-Based Urban Terrain Reconstruction from Uav-Videos for Geoinformation Applications

NASA Astrophysics Data System (ADS)

Bulatov, D.; Solbrig, P.; Gross, H.; Wernerus, P.; Repasi, E.; Heipke, C.

2011-09-01

Urban terrain reconstruction has many applications in areas of civil engineering, urban planning, surveillance and defense research. Therefore the needs of covering ad-hoc demand and performing a close-range urban terrain reconstruction with miniaturized and relatively inexpensive sensor platforms are constantly growing. Using (miniaturized) unmanned aerial vehicles, (M)UAVs, represents one of the most attractive alternatives to conventional large-scale aerial imagery. We cover in this paper a four-step procedure of obtaining georeferenced 3D urban models from video sequences. The four steps of the procedure - orientation, dense reconstruction, urban terrain modeling and geo-referencing - are robust, straight-forward, and nearly fully-automatic. The two last steps - namely, urban terrain modeling from almost-nadir videos and co-registration of models 6ndash; represent the main contribution of this work and will therefore be covered with more detail. The essential substeps of the third step include digital terrain model (DTM) extraction, segregation of buildings from vegetation, as well as instantiation of building and tree models. The last step is subdivided into quasi- intrasensorial registration of Euclidean reconstructions and intersensorial registration with a geo-referenced orthophoto. Finally, we present reconstruction results from a real data-set and outline ideas for future work.

Experimental study on the stability and failure of individual step-pool

NASA Astrophysics Data System (ADS)

Zhang, Chendi; Xu, Mengzhen; Hassan, Marwan A.; Chartrand, Shawn M.; Wang, Zhaoyin

2018-06-01

Step-pools are one of the most common bedforms in mountain streams, the stability and failure of which play a significant role for riverbed stability and fluvial processes. Given this importance, flume experiments were performed with a manually constructed step-pool model. The experiments were carried out with a constant flow rate to study features of step-pool stability as well as failure mechanisms. The results demonstrate that motion of the keystone grain (KS) caused 90% of the total failure events. The pool reached its maximum depth and either exhibited relative stability for a period before step failure, which was called the stable phase, or the pool collapsed before its full development. The critical scour depth for the pool increased linearly with discharge until the trend was interrupted by step failure. Variability of the stable phase duration ranged by one order of magnitude, whereas variability of pool scour depth was constrained within 50%. Step adjustment was detected in almost all of the runs with step-pool failure and was one or two orders smaller than the diameter of the step stones. Two discharge regimes for step-pool failure were revealed: one regime captures threshold conditions and frames possible step-pool failure, whereas the second regime captures step-pool failure conditions and is the discharge of an exceptional event. In the transitional stage between the two discharge regimes, pool and step adjustment magnitude displayed relatively large variabilities, which resulted in feedbacks that extended the duration of step-pool stability. Step adjustment, which was a type of structural deformation, increased significantly before step failure. As a result, we consider step deformation as the direct explanation to step-pool failure rather than pool scour, which displayed relative stability during step deformations in our experiments.

[Influence of thermalcycling on bonding durability of self-etch adhesives with dentin].

PubMed

Tian, Fu-cong; Wang, Xiao-yan; Gao, Xue-jun

2014-04-18

To investigate influence of thermalcycling on the bonding durability of two one-step products [Adper Prompt (AP) and G-bond (GB)] and one two-step self-etching adhesive [Clearfil SE bond (SE)] with dentin in vitro. Forty-two extracted human molars were selected. The superficial dentin was exposed by grinding off the enamel. The teeth were randomly distributed into six groups with varied bonding protocols. The adhesives were applied to the dentin surface. Composite crowns were built up, then the samples were cut longitudinally into sticks with 1.0 mm×1.0 mm bonding area [for microtensile bond strength (MTBS) testing] or 1.0 mm thick slabs (for nanoleakage observation). Bonding performance was evaluated with or without thermalcyling. For the MTBS testing, the strength values were statistically analysed using One-Way ANOVA. Four slabs in each group were observed for nanoleakage by SEM with a backscattered electron detector. Thermalcycling procedures affected MTBS. In the two one-step groups, the MTBS decreased significantly (P<0.05) after thermalcycling [AP group from (19.06±1.50) MPa to (12.62±2.10) MPa; GB group from (17.75±1.10) MPa to (6.24±0.42)MPa]. But in SE groups, MTBS did not significantly affect [(45.80±2.97) MPa compared with(40.60±5.76) MPa]. As a whole, one-step self-etching adhesives showed lower MTBS than two-step bonding system after aging.For AP and GB, continuous nanoleakage appearance was notable and more obvious than for SE. Thermalcycling can affect the bonding performance of self-etch adhesives including decrease of bond strength and nanoleakage pattern. one-step self-etch adhesives showed more obvious change compared with their two-step counterparts.

Uncovering of melanin fluorescence in human skin tissue

NASA Astrophysics Data System (ADS)

Scholz, Matthias; Stankovic, Goran; Seewald, Gunter; Leupold, Dieter

2007-07-01

Due to its extremely low fluorescence quantum yield, in the conventionally (one-photon) excited autofluorescence of skin tissue, melanin fluorescence is masked by several other endogenous and possibly also exogenous fluorophores (e.g. NADH, FAD, Porphyrins). A first step to enhance the melanin contribution had been realized by two-photon fs-pulse excitation in the red/near IR, based on the fact that melanin can be excited by stepwise two-photon absorption, whereas all other fluorophores in this spectral region allow only simultaneous two-photon excitation. Now, the next and decisive step has been realized: Using an extremely sensitive detection system, for the first time twophoton fluorescence of skin tissue excited with pulses in the ns-range could be measured. The motivation for this step was based on the fact that the population density of the fluorescent level resulting from a stepwise excitation has a different dependence of the pulse duration than that from a simultaneous excitation (Δt2 vs. Δt). Due to this strong discrimination between the fluorophores, practically pure melanin fluorescence can be obtained. Examples for in-vivo, ex-vivo as well as paraffin embedded skin tissue will be shown. The content of information with respect to early diagnosis of skin deseases will be discussed.

The effect of adopting the IADPSG screening guidelines on the risk profile and outcomes of the gestational diabetes population

PubMed Central

March, Melissa I.; Modest, Anna M.; Ralston, Steven J.; Hacker, Michele R.; Gupta, Munish; Brown, Florence M.

2016-01-01

Abstract Objective: To compare characteristics and outcomes of women diagnosed with gestational diabetes mellitus (GDM) by the newer one-step glucose tolerance test and those diagnosed with the traditional two-step method. Research design and methods: This was a retrospective cohort study of women with GDM who delivered in 2010–2011. Data are reported as proportion or median (interquartile range) and were compared using a Chi-square, Fisher's exact or Wilcoxon rank sum test based on data type. Results: Of 235 women with GDM, 55.7% were diagnosed using the two-step method and 44.3% with the one-step method. The groups had similar demographics and GDM risk factors. The two-step method group was diagnosed with GDM one week later [27.0 (24.0–29.0) weeks versus 26.0 (24.0–28.0 weeks); p = 0.13]. The groups had similar median weight gain per week before diagnosis. After diagnosis, women in the one-step method group had significantly higher median weight gain per week [0.67 pounds/week (0.31–1.0) versus 0.56 pounds/week (0.15–0.89); p = 0.047]. In the one-step method group more women had suspected macrosomia (11.7% versus 5.3%, p = 0.07) and more neonates had a birth weight >4000 g (13.6% versus 7.5%, p = 0.13); however, these differences were not statistically significant. Other pregnancy and neonatal complications were similar. Conclusions: Women diagnosed with the one-step method gained more weight per week after GDM diagnosis and had a non-statistically significant increased risk for suspected macrosomia. Our data suggest the one-step method identifies women with at least equally high risk as the two-step method. PMID:25958989

Hierarchical modeling of heat transfer in silicon-based electronic devices

NASA Astrophysics Data System (ADS)

Goicochea Pineda, Javier V.

In this work a methodology for the hierarchical modeling of heat transfer in silicon-based electronic devices is presented. The methodology includes three steps to integrate the different scales involved in the thermal analysis of these devices. The steps correspond to: (i) the estimation of input parameters and thermal properties required to solve the Boltzmann transport equation (BTE) for phonons by means of molecular dynamics (MD) simulations, (ii) the quantum correction of some of the properties estimated with MD to make them suitable for BTE and (iii) the numerical solution of the BTE using the lattice Boltzmann method (LBM) under the single mode relaxation time approximation subject to different initial and boundary conditions, including non-linear dispersion relations and different polarizations in the [100] direction. Each step of the methodology is validated with numerical, analytical or experimental reported data. In the first step of the methodology, properties such as, phonon relaxation times, dispersion relations, group and phase velocities and specific heat are obtained with MD at of 300 and 1000 K (i.e. molecular temperatures). The estimation of the properties considers the anhamonic nature of the potential energy function, including the thermal expansion of the crystal. Both effects are found to modify the dispersion relations with temperature. The behavior of the phonon relaxation times for each mode (i.e. longitudinal and transverse, acoustic and optical phonons) is identified using power functions. The exponents of the acoustic modes are agree with those predicted theoretically perturbation theory at high temperatures, while those for the optical modes are higher. All properties estimated with MD are validated with values for the thermal conductivity obtained from the Green-Kubo method. It is found that the relative contribution of acoustic modes to the overall thermal conductivity is approximately 90% at both temperatures. In the second step, two new quantum correction alternatives are applied to correct the results obtained with MD. The alternatives consider the quantization of the energy per phonon mode. In addition, the effect of isotope scattering is included in the phonon-phonon relaxation time values previously determined in the first step. It is found that both the quantization of the energy and the inclusion of scattering with isotopes significant reduce the contribution of high-frequency modes to the overall thermal conductivity. After these two effects are considered, the contribution of optical modes reduces to less than 2.4%. In this step, two sets of properties are obtained. The first one results from the application of quantum corrections to abovementioned properties, while the second is obtained including also the isotope scattering. These sets of properties are identified in this work as isotope-enriched silicon (isoSi) and natural silicon (natSi) and are used along other phonon relaxation time models in the last step of our methodology. Before we solve the BTE using the LBM, a new dispersive lattice Boltzmann formulation is proposed. The new dispersive formulation is based on constant lattice spacings (CLS) and flux limiters, rather than constant time steps (as previously reported). It is found that the new formulation significantly reduces the computation cost and complexity of the solution of the BTE, without affecting the thermal predictions. Lastly, in the last step of our methodology, we solve the BTE. The equation is solved under the relaxation time approximation using our thermal properties estimated for isoSi and natSi and using two phonon formulations. The phonon formulations include a gray model and the new dispersive method. For comparison purposes, the BTE is also solved using the phenomenological and theoretical phonon relaxation time models of Holland, and Han and Klemens. Different thermal predictions in steady and transient states are performed to illustrate the application of the methodology in one- and two-dimensional silicon films and in silicon-over-insulator (SOI) transistors. These include the determination of bulk and film thermal conductivities (i.e. out-of-plane and in-plane), and the transient evolution of the wall heat flux and temperature for films of different thicknesses. In addition, the physics of phonons is further analyzed in terms of the influence and behavior of acoustic and optical modes in the thermal predictions and the effect of phonon confinement in the thermal response of SOI-like transistors subject to different self-heating conditions.

One-Step and Two-Step Facility Acquisition for Military Construction: Project Selection and Implementation Procedures

DTIC Science & Technology

1990-08-01

the guidance in this report. 1-4. Scope This guidance covers selection of projects suitable for a One-Step or Two-Step approach, development of design...conducted, focus on resolving proposal deficiencies; prices are not "negotiated" in the common use of the term. A Request for Proposal (RFP) states project ...carefully examines experience and past performance in the design of similar projects and building types. Quality of

Microtensile bond strength of eleven contemporary adhesives to enamel.

PubMed

Inoue, Satoshi; Vargas, Marcos A; Abe, Yasuhiko; Yoshida, Yasuhiro; Lambrechts, Paul; Vanherle, Guido; Sano, Hidehiko; Van Meerbeek, Bart

2003-10-01

To compare the microtensile bond strength (microTBS) to enamel of 10 contemporary adhesives, including three one-step self-etch systems, four two-step self-etch systems and three two-step total-etch systems, with that of a conventional three-step total-etch adhesive. Resin composite (Z100, 3M) was bonded to flat, #600-grit wet-sanded enamel surfaces of 18 extracted human third molars using the adhesives strictly according to the respective manufacturer's instructions. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into 2-4 thin slabs of approximately 1 mm thickness and 2.5 mm width. They were then trimmed into an hourglass shape with an interface area of approximately 1 mm2, and subsequently subjected to microTBS-testing with a cross-head speed of 1 mm/minute. The microTBS to enamel varied from 3.2 MPa for the experimental one-step self-etch adhesive PQ/Universal (self-etch) to 43.9 MPa for the two-step total-etch adhesive Scotchbond 1. When compared with the conventional three-step total-etch adhesive OptiBond FL, the bond strengths of most adhesives with simplified application procedures were not significantly different, except for two one-step self-etch adhesives, experimental PQ/Universal (self-etch) and One-up Bond F, that showed lower bond strengths. Specimen failures during sample preparation were recorded for the latter adhesives as well.

[Reduction of livestock-associated methicillin-resistant staphylococcus aureus (LA-MRSA) in the exhaust air of two piggeries by a bio-trickling filter and a biological three-step air cleaning system].

PubMed

Clauss, Marcus; Schulz, Jochen; Stratmann-Selke, Janin; Decius, Maja; Hartung, Jörg

2013-01-01

"Livestock-associated" Methicillin-resistent Staphylococcus aureus (LA-MRSA) are frequently found in the air of piggeries, are emitted into the ambient air of the piggeries and may also drift into residential areas or surrounding animal husbandries.. In order to reduce emissions from animal houses such as odour, gases and dust different biological air cleaning systems are commercially available. In this study the retention efficiencies for the culturable LA-MRSA of a bio-trickling filter and a combined three step system, both installed at two different piggeries, were investigated. Raw gas concentrations for LA-MRSA of 2.1 x 10(2) cfu/m3 (biotrickling filter) and 3.9 x 10(2) cfu/m3 (three step system) were found. The clean gas concentrations were in each case approximately one power of ten lower. Both systems were able to reduce the number of investigated bacteria in the air of piggeries on average about 90%. The investigated systems can contribute to protect nearby residents. However, considerable fluctuations of the emissions can occur.

Biologic considerations regarding the one and two step procedures in the management of patients with invasive carcinoma of the breast.

PubMed

Fisher, E R; Sass, R; Fisher, B

1985-09-01

Investigation of the biologic significance of delay between biopsy and mastectomy was performed upon women with invasive carcinoma of the breast in protocol four of the NSABP. Since the period of delay was two weeks or less in approximately 75 per cent, no comment concerning the possible effects of longer periods can be made. Life table analyses failed to reveal any difference in ten year survival rates between patients undergoing radical mastectomy management by the one and two step procedures. Similarly, no difference in adjusted ten year survival rate was observed between women managed by the two step procedure who did or did not have residual tumor identified in the mastectomy specimen after the first step or biopsy. Importantly, the clinical or pathologic stages, sizes of tumor or histologic grades were similar in women managed by the one and two step procedures minimizing selection bias. The material used also allowed for study of the possible causative role of biopsy of the breast on the development of sinus histiocytosis in regional axillary lymph nodes. No difference in degree or types of this nodal reaction could be discerned in the lymph nodes of the mastectomy specimens obtained from patients who had undergone the one and two step procedures. This finding indicates that nodal sinus histiocytosis is indeed related to the neoplastic process, albeit in an undefined manner, rather than the trauma of biopsy per se as has been suggested. These results do not invalidate the use of the one step procedure in the management of patients with carcinoma of the breast. Indeed, it is highly likely that it will be commonly used now that breast-conserving operations appear to represent a viable alternative modality for the primary surgical treatment of carcinoma of the breast. Yet, it is apparent that the one step procedure will be performed for technical and practical rather than biologic reasons.

Influence of ageing on self-etch adhesives: one-step vs. two-step systems.

PubMed

Marchesi, Giulio; Frassetto, Andrea; Visintini, Erika; Diolosà, Marina; Turco, Gianluca; Salgarello, Stefano; Di Lenarda, Roberto; Cadenaro, Milena; Breschi, Lorenzo

2013-02-01

The aim of this study was to evaluate microtensile bond strength (μTBS) to dentine, interfacial nanoleakage expression, and stability after ageing, of two-step vs. one-step self-etch adhesives. Human molars were cut to expose middle/deep dentine, assigned to groups (n = 15), and treated with the following bonding systems: (i) Optibond XTR (a two-step self-etch adhesive; Kerr), (ii) Clearfil SE Bond (a two-step self-etch adhesive; Kuraray), (iii) Adper Easy Bond (a one-step self-etch adhesive; 3M ESPE), and (iv) Bond Force (a one-step self-etch adhesive; Tokuyama). Specimens were processed for μTBS testing after 24 h, 6 months, or 1 yr of storage in artificial saliva at 37°C. Nanoleakage expression was examined in similarly processed additional specimens. At baseline the μTBS results ranked in the following order: Adper Easy Bond = Optibond XTR ≥Clearfil SE = Bond Force, and interfacial nanoleakage analysis showed Clearfil SE Bond = Adper Easy Bond = Optibond XTR> Bond Force. After 1 yr of storage, Optibond XTR, Clearfil SE Bond, and Adper Easy Bond showed higher μTBS and lower interfacial nanoleakage expression compared with Bond Force. In conclusion, immediate bond strength, nanoleakage expression, and stability over time were not related to the number of steps of the bonding systems, but to their chemical formulations. © 2012 Eur J Oral Sci.

A two steps solution approach to solving large nonlinear models: application to a problem of conjunctive use.

PubMed

Vieira, J; Cunha, M C

2011-01-01

This article describes a solution method of solving large nonlinear problems in two steps. The two steps solution approach takes advantage of handling smaller and simpler models and having better starting points to improve solution efficiency. The set of nonlinear constraints (named as complicating constraints) which makes the solution of the model rather complex and time consuming is eliminated from step one. The complicating constraints are added only in the second step so that a solution of the complete model is then found. The solution method is applied to a large-scale problem of conjunctive use of surface water and groundwater resources. The results obtained are compared with solutions determined with the direct solve of the complete model in one single step. In all examples the two steps solution approach allowed a significant reduction of the computation time. This potential gain of efficiency of the two steps solution approach can be extremely important for work in progress and it can be particularly useful for cases where the computation time would be a critical factor for having an optimized solution in due time.

Comparison of patency and cost-effectiveness of self-expandable metal and plastic stents used for malignant biliary strictures: a Polish single-center study.

PubMed

Budzyńska, Agnieszka; Nowakowska-Duława, Ewa; Marek, Tomasz; Hartleb, Marek

2016-10-01

Most patients with malignant biliary obstruction are suited only for palliation by endoscopic drainage with plastic stents (PS) or self-expandable metal stents (SEMS). To compare the clinical outcome and costs of biliary stenting with SEMS and PS in patients with malignant biliary strictures. A total of 114 patients with malignant jaundice who underwent 376 endoscopic retrograde biliary drainage (ERBD) were studied. ERBD with the placement of PS was performed in 80 patients, with one-step SEMS in 20 patients and two-step SEMS in 14 patients. Significantly fewer ERBD interventions were performed in patients with one-step SEMS than PS or the two-step SEMS technique (2.0±1.12 vs. 3.1±1.7 or 5.7±2.1, respectively, P<0.0001). The median hospitalization duration per procedure was similar for the three groups of patients. The patients' survival time was the longest in the two-step SEMS group in comparison with the one-step SEMS and PS groups (596±270 vs. 276±141 or 208±219 days, P<0.001). Overall median time to recurrent biliary obstruction was 89.3±159 days for PS and 120.6±101 days for SEMS (P=0.01). The total cost of hospitalization with ERBD was higher for two-step SEMS than for one-step SEMS or PS (1448±312, 1152±135 and 977±156&OV0556;, P<0.0001). However, the estimated annual cost of medical care for one-step SEMS was higher than that for the two-step SEMS or PS groups (4618, 4079, and 3995&OV0556;, respectively). Biliary decompression by SEMS is associated with longer patency and reduced number of auxiliary procedures; however, repeated PS insertions still remain the most cost-effective strategy.

Indirect contributions to electron-impact ionization of Li+ (1 s 2 s S31 ) ions: Role of intermediate double-K -vacancy states

NASA Astrophysics Data System (ADS)

Müller, A.; Borovik, A.; Huber, K.; Schippers, S.; Fursa, D. V.; Bray, I.

2018-02-01

Fine details of the cross section for electron-impact ionization of metastable two-electron Li+(1 s 2 s S31) ions are scrutinized by both experiment and theory. Beyond direct knockoff ionization, indirect ionization mechanisms proceeding via formation of intermediate double-K-vacancy (hollow) states either in a Li+ ion or in a neutral lithium atom and subsequent emission of one or two electrons, respectively, can contribute to the net production of Li2 + ions. The partial cross sections for such contributions are less than 4% of the total single-ionization cross section. The characteristic steps, resonances, and interference phenomena in the indirect ionization contribution are measured with an experimental energy spread of less than 0.9 eV and with a statistical relative uncertainty of the order of 1.7%, requiring a level of statistical uncertainty in the total single-ionization cross section of better than 0.05%. The measurements are accompanied by convergent-close-coupling calculations performed on a fine energy grid. Theory and experiment are in remarkable agreement concerning the fine details of the ionization cross section. Comparison with previous R-matrix results is less favorable.

Processing of zero-derived words in English: an fMRI investigation.

PubMed

Pliatsikas, Christos; Wheeldon, Linda; Lahiri, Aditi; Hansen, Peter C

2014-01-01

Derivational morphological processes allow us to create new words (e.g. punish (V) to noun (N) punishment) from base forms. The number of steps from the basic units to derived words often varies (e.g., nationalitybridge-V) i.e., zero-derivation (Aronoff, 1980). We compared the processing of one-step (soaking

Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting.

PubMed

Rashed-Ul Islam, S M; Jahan, Munira; Tabassum, Shahina

2015-01-01

Virological monitoring is the best predictor for the management of chronic hepatitis B virus (HBV) infections. Consequently, it is important to use the most efficient, rapid and cost-effective testing systems for HBV DNA quantification. The present study compared the performance characteristics of a one-step HBV polymerase chain reaction (PCR) vs the two-step HBV PCR method for quantification of HBV DNA from clinical samples. A total of 100 samples consisting of 85 randomly selected samples from patients with chronic hepatitis B (CHB) and 15 samples from apparently healthy individuals were enrolled in this study. Of the 85 CHB clinical samples tested, HBV DNA was detected from 81% samples by one-step PCR method with median HBV DNA viral load (VL) of 7.50 × 10 3 lU/ml. In contrast, 72% samples were detected by the two-step PCR system with median HBV DNA of 3.71 × 10 3 lU/ml. The one-step method showed strong linear correlation with two-step PCR method (r = 0.89; p < 0.0001). Both methods showed good agreement at Bland-Altman plot, with a mean difference of 0.61 log 10 IU/ml and limits of agreement of -1.82 to 3.03 log 10 IU/ml. The intra-assay and interassay coefficients of variation (CV%) of plasma samples (4-7 log 10 IU/ml) for the one-step PCR method ranged between 0.33 to 0.59 and 0.28 to 0.48 respectively, thus demonstrating a high level of concordance between the two methods. Moreover, elimination of the DNA extraction step in the one-step PCR kit allowed time-efficient and significant labor and cost savings for the quantification of HBV DNA in a resource limited setting. Rashed-Ul Islam SM, Jahan M, Tabassum S. Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting. Euroasian J Hepato-Gastroenterol 2015;5(1):11-15.

Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting

PubMed Central

Jahan, Munira; Tabassum, Shahina

2015-01-01

Virological monitoring is the best predictor for the management of chronic hepatitis B virus (HBV) infections. Consequently, it is important to use the most efficient, rapid and cost-effective testing systems for HBV DNA quantification. The present study compared the performance characteristics of a one-step HBV polymerase chain reaction (PCR) vs the two-step HBV PCR method for quantification of HBV DNA from clinical samples. A total of 100 samples consisting of 85 randomly selected samples from patients with chronic hepatitis B (CHB) and 15 samples from apparently healthy individuals were enrolled in this study. Of the 85 CHB clinical samples tested, HBV DNA was detected from 81% samples by one-step PCR method with median HBV DNA viral load (VL) of 7.50 × 103 lU/ml. In contrast, 72% samples were detected by the two-step PCR system with median HBV DNA of 3.71 × 103 lU/ml. The one-step method showed strong linear correlation with two-step PCR method (r = 0.89; p < 0.0001). Both methods showed good agreement at Bland-Altman plot, with a mean difference of 0.61 log10 IU/ml and limits of agreement of -1.82 to 3.03 log10 IU/ml. The intra-assay and interassay coefficients of variation (CV%) of plasma samples (4-7 log10 IU/ml) for the one-step PCR method ranged between 0.33 to 0.59 and 0.28 to 0.48 respectively, thus demonstrating a high level of concordance between the two methods. Moreover, elimination of the DNA extraction step in the one-step PCR kit allowed time-efficient and significant labor and cost savings for the quantification of HBV DNA in a resource limited setting. How to cite this article Rashed-Ul Islam SM, Jahan M, Tabassum S. Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting. Euroasian J Hepato-Gastroenterol 2015;5(1):11-15. PMID:29201678

In vitro and in vivo testing of a novel recessed-step catheter for reflux-free convection-enhanced drug delivery to the brain.

PubMed

Gill, T; Barua, N U; Woolley, M; Bienemann, A S; Johnson, D E; S O'Sullivan; Murray, G; Fennelly, C; Lewis, O; Irving, C; Wyatt, M J; Moore, P; Gill, S S

2013-09-30

The optimisation of convection-enhanced drug delivery (CED) to the brain is fundamentally reliant on minimising drug reflux. The aim of this study was to evaluate the performance of a novel reflux-resistant CED catheter incorporating a recessed-step and to compare its performance to previously described stepped catheters. The in vitro performance of the recessed-step catheter was compared to a conventional "one-step" catheter with a single transition in outer diameter (OD) at the catheter tip, and a "two-step" design comprising two distal transitions in OD. The volumes of distribution and reflux were compared by performing infusions of Trypan blue into agarose gels. The in vivo performance of the recessed-step catheter was then analysed in a large animal model by performing infusions of 0.2% Gadolinium-DTPA in Large White/Landrace pigs. The recessed-step catheter demonstrated significantly higher volumes of distribution than the one-step and two-step catheters (p=0.0001, one-way ANOVA). No reflux was detected until more than 100 ul had been delivered via the recessed-step catheter, whilst reflux was detected after infusion of only 25 ul via the 2 non-recessed catheters. The recessed-step design also showed superior reflux resistance to a conventational one-step catheter in vivo. Reflux-free infusions were achieved in the thalamus, putamen and white matter at a maximum infusion rate of 5 ul/min using the recessed-step design. The novel recessed-step catheter described in this study shows significant potential for the achievement of predictable high volume, high flow rate infusions whilst minimising the risk of reflux. Copyright © 2013 Elsevier B.V. All rights reserved.

The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes

NASA Astrophysics Data System (ADS)

Bissadi, Golnaz

Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS). The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique. The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system. The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.

Sealing properties of one-step root-filling fibre post-obturators vs. two-step delayed fibre post-placement.

PubMed

Monticelli, Francesca; Osorio, Raquel; Toledano, Manuel; Ferrari, Marco; Pashley, David H; Tay, Franklin R

2010-07-01

The sealing properties of a one-step obturation post-placement technique consisting of Resilon-capped fibre post-obturators were compared with a two-step technique based on initial Resilon root filling following by 24h-delayed fibre post-placement. Thirty root segments were shaped to size 40, 0.04 taper and filled with: (1) InnoEndo obturators; (2) Resilon/24h-delayed FibreKor post-cementation. Obturator, root filling and post-cementation procedures were performed using InnoEndo bonding agent/dual-cured root canal sealer. Fluid flow rate through the filled roots was evaluated at 10psi using a computerised fluid filtration model before root resection and after 3 and 9mm apical resections. Fluid flow data were analysed using two-way repeated measures ANOVA and Tukey test to examine the effects of root-filling post-placement techniques and root resection lengths on fluid leakage from the filled canals (alpha=0.05). A significantly greater amount of fluid leakage was observed with the one-step technique when compared with two-step technique. No difference in fluid leakage was observed among intact canals and canals resected at different lengths for both materials. The seal of root canals achieved with the one-step obturator is less effective than separate Resilon root fillings followed by a 24-h delay prior to the fibre post-placement. Incomplete setting of the sealer and restricted relief of polymerisation shrinkage stresses may be responsible for the inferior seal of the one-step root-filling/post-restoration technique. Copyright 2010 Elsevier Ltd. All rights reserved.

Contribution of first- versus second-generation products to secondary organic aerosols formed in the oxidation of biogenic hydrocarbons.

PubMed

Ng, Nga L; Kroll, Jesse H; Keywood, Melita D; Bahreini, Roya; Varutbangkul, Varuntida; Flagan, Richard C; Seinfeld, John H; Lee, Anita; Goldstein, Allen H

2006-04-01

Biogenic hydrocarbons emitted by vegetation are important contributors to secondary organic aerosol (SOA), but the aerosol formation mechanisms are incompletely understood. In this study, the formation of aerosols and gas-phase products from the ozonolysis and photooxidation of a series of biogenic hydrocarbons (isoprene, 8 monoterpenes, 4 sesquiterpenes, and 3 oxygenated terpenes) are examined. By comparing aerosol growth (measured by Differential Mobility Analyzers, DMAs) and gas-phase concentrations (monitored by a Proton Transfer Reaction Mass Spectrometer, PTR-MS), we study the general mechanisms of SOA formation. Aerosol growth data are presented in terms of a "growth curve", a plot of aerosol mass formed versus the amount of hydrocarbon reacted. From the shapes of the growth curves, it is found that all the hydrocarbons studied can be classified into two groups based entirely on the number of double bonds of the hydrocarbon, regardless of the reaction systems (ozonolysis or photooxidation) and the types of hydrocarbons studied: compounds with only one double bond and compounds with more than one double bond. For compounds with only one double bond, the first oxidation step is rate-limiting, and aerosols are formed mainly from low volatility first-generation oxidation products; whereas for compounds with more than one double bond, the second oxidation step may also be rate-limiting and second-generation products contribute substantially to SOA growth. This behavior is characterized by a vertical section in the growth curve, in which continued aerosol growth is observed even after all the parent hydrocarbon is consumed.

Physical activity among children: objective measurements using Fitbit One® and ActiGraph.

PubMed

Hamari, Lotta; Kullberg, Tiina; Ruohonen, Jukka; Heinonen, Olli J; Díaz-Rodríguez, Natalia; Lilius, Johan; Pakarinen, Anni; Myllymäki, Annukka; Leppänen, Ville; Salanterä, Sanna

2017-04-20

Self-quantification of health parameters is becoming more popular; thus, the validity of the devices requires assessments. The aim of this study was to evaluate the validity of Fitbit One step counts (Fitbit Inc., San Francisco, CA, USA) against Actigraph wActisleep-BT step counts (ActiGraph, LLC, Pensacola, FL, USA) for measuring habitual physical activity among children. The study was implemented as a cross-sectional experimental design in which participants carried two waist-worn activity monitors for five consecutive days. The participants were chosen with a purposive sampling from three fourth grade classes (9-10 year olds) in two comprehensive schools. Altogether, there were 34 participants in the study. From these, eight participants were excluded from the analysis due to erroneous data. Primary outcome measures for step counts were Fitbit One and Actigraph wActisleep-BT. The supporting outcome measures were based on activity diaries and initial information sheets. Classical Bland-Altman plots were used for reporting the results. The average per-participant daily difference between the step counts from the two devices was 1937. The range was [116, 5052]. Fitbit One gave higher step counts for all but the least active participant. According to a Bland-Altman plot, the hourly step counts had a relative large mean bias across participants (161 step counts). The differences were partially explained by activity intensity: higher intensity denoted higher differences, and light intensity denoted lower differences. Fitbit One step counts are comparable to Actigraph step counts in a sample of 9-10-year-old children engaged in habitual physical activity in sedentary and light physical activity intensities. However, in moderate-to-vigorous physical activity, Fitbit One gives higher step counts when compared to Actigraph.

A new one-step procedure for pulmonary valve implantation of the melody valve: Simultaneous prestenting and valve implantation.

PubMed

Boudjemline, Younes

2018-01-01

To describe a new modification, the one-step procedure, that allows interventionists to pre-stent and implant a Melody valve simultaneously. Percutaneous pulmonary valve implantation (PPVI) is the standard of care for managing patients with dysfunctional right ventricular outflow tract, and the approach is standardized. Patients undergoing PPVI using the one-step procedure were identified in our database. Procedural data and radiation exposure were compared to those in a matched group of patients who underwent PPVI using the conventional two-step procedure. Between January 2016 and January 2017, PPVI was performed in 27 patients (median age/range, 19.1/10-55 years) using the one-step procedure involving manual crimping of one to three bare metal stents over the Melody valve. The stent and Melody valve were delivered successfully using the Ensemble delivery system. No complications occurred. All patients had excellent hemodynamic results (median/range post-PPVI right ventricular to pulmonary artery gradient, 9/0-20 mmHg). Valve function was excellent. Median procedural and fluoroscopic times were 56 and 10.2 min, respectively, which significantly differed from those of the two-step procedure group. Similarly, the dose area product (DAP), and radiation time were statistically lower in the one-step group than in the two-step group (P < 0.001 for all variables). After a median follow-up of 8 months (range, 3-14.7), no patient underwent reintervention, and no device dysfunction was observed. The one-step procedure is a safe modification that allows interventionists to prestent and implants the Melody valve simultaneously. It significantly reduces procedural and fluoroscopic times, and radiation exposure. © 2017 Wiley Periodicals, Inc.

Evaluation of Lumicyano™ cyanoacrylate fuming process for the development of latent fingermarks on plastic carrier bags by means of a pseudo operational comparative trial.

PubMed

Farrugia, Kevin J; Deacon, Paul; Fraser, Joanna

2014-03-01

There are a number of studies discussing recent developments of a one-step fluorescent cyanoacrylate process. This study is a pseudo operational trial to compare an example of a one-step fluorescent cyanoacrylate product, Lumicyano™, with the two recommended techniques for plastic carrier bags; cyanoacrylate fuming followed by basic yellow 40 (BY40) dyeing and powder suspensions. 100 plastic carrier bags were collected from the place of work and the items were treated as found without any additional fingermark deposition. The bags were split into three and after treatment with the three techniques a comparable number of fingermarks were detected by each technique (average of 300 fingermarks). The items treated with Lumicyano™ were sequentially processed with BY40 and an additional 43 new fingermarks were detected. Lumicyano™ appears to be a suitable technique for the development of fingermarks on plastic carrier bags and it can help save lab space and time as it does not require dyeing or drying procedures. Furthermore, contrary to other one-step cyanoacrylate products, existing cyanoacrylate cabinets do not require any modification for the treatment of articles with Lumicyano™. To date, there is little peer reviewed articles in the literature on trials related to Lumicyano™ and this study aims to contribute to fill this gap. © 2013.

Comparing two versions of the Karolinska Sleepiness Scale (KSS).

PubMed

Miley, Anna Åkerstedt; Kecklund, Göran; Åkerstedt, Torbjörn

2016-01-01

The Karolinska Sleepiness Scale (KSS) is frequently used to study sleepiness in various contexts. However, it exists in two versions, one with labels on every other step (version A), and one with labels on every step (version B) on the 9-point scale. To date, there are no studies examining whether these versions can be used interchangeably. The two versions were here compared in a 24 hr wakefulness study of 12 adults. KSS ratings were obtained every hour, alternating version A and B. Results indicated that the two versions are highly correlated, do not have different response distributions on labeled and unlabeled steps, and that the distributions across all steps have a high level of correspondence (Kappa = 0.73). It was concluded that the two versions are quite similar.

Emotional influences on locomotor behavior.

PubMed

Naugle, Kelly M; Joyner, Jessica; Hass, Chris J; Janelle, Christopher M

2010-12-01

Emotional responses to appetitive and aversive stimuli motivate approach and avoidance behaviors essential for survival. The purpose of the current study was to determine the impact of specific emotional stimuli on forward, approach-oriented locomotion. Steady state walking was assessed while participants walked toward pictures varying in emotional content (erotic, happy people, attack, mutilation, contamination, and neutral). Step length and step velocity were calculated for the first two steps following picture onset. Exposure to the mutilation and contamination pictures shortened the lengths of step one and step two compared to the erotic pictures. Additionally, step velocity was greater during exposure to the erotic pictures compared to (1) the contamination and mutilation pictures for step one and (2) all other picture categories for step two. These findings suggest that locomotion is facilitated when walking toward approach-oriented emotional stimuli but compromised when walking toward aversive emotional stimuli. The data extend our understanding of fundamental interactions among motivational orientations, emotional reactions, and resultant actions. Theoretical and practical implications are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Source apportionment and a novel approach of estimating regional contributions to ambient PM2.5 in Haikou, China.

PubMed

Liu, Baoshuang; Li, Tingkun; Yang, Jiamei; Wu, Jianhui; Wang, Jiao; Gao, Jixin; Bi, Xiaohui; Feng, Yinchang; Zhang, Yufen; Yang, Haihang

2017-04-01

A novel approach was developed to estimate regional contributions to ambient PM 2.5 in Haikou, China. In this paper, the investigation was divided into two main steps. The first step: analysing the characteristics of the chemical compositions of ambient PM 2.5 , as well as the source profiles, and then conducting source apportionments by using the CMB and CMB-Iteration models. The second step: the development of estimation approaches for regional contributions in terms of local features of Haikou and the results of source apportionment, and estimating regional contributions to ambient PM 2.5 in Haikou by this new approach. The results indicate that secondary sulphate, resuspended dust and vehicle exhaust were the major sources of ambient PM 2.5 in Haikou, contributing 9.9-21.4%, 10.1-19.0% and 10.5-20.2%, respectively. Regional contributions to ambient PM 2.5 in Haikou in spring, autumn and winter were 22.5%, 11.6% and 32.5%, respectively. The regional contribution in summer was assumed to be zero according to the better atmospheric quality and assumptions of this new estimation approach. The higher regional contribution in winter might be mainly attributable to the transport of polluted air originating in mainland China, especially from the north, where coal is burned for heating in winter. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Discordant MZ-Twin Method: One Step Closer to the Holy Grail of Causality

ERIC Educational Resources Information Center

Vitaro, Frank; Brendgen, Mara; Arseneault, Louise

2009-01-01

Twin studies are well known for their value in quantifying the contribution of genes to population variation in behaviors and personality traits. Twin studies also provide a unique opportunity to untangle the contribution of environmental experiences to emotional and behavioral development. This is particularly true when examining monozygotic (MZ)…

Relation between the microstructure and the electromagnetic properties of BaTiO3/Ni0.5Zn0.5Fe2O4 ceramic composite

NASA Astrophysics Data System (ADS)

Xiao, Bin; Tang, Yu; Ma, Guodong; Ma, Ning; Du, Piyi

2015-06-01

The microstructure-property relation in ferroelectric/ferromagnetic composite is investigated in detail, exemplified by typical sol-gel-derived 0.3BTO/0.7NZFO ceramic composite. The effect of microstructural factors including intergrain connectivity, grain size and interfaces on the dielectric and magnetic properties of the composite prepared by conventional ceramic method and three-step sintering method is discussed both experimentally and theoretically. It reveals that the dielectric behavior of the composite is controlled by a hybrid dielectric process that combines the contribution of Debye-like dipoles and Maxwell-Wagner (M-W or interfacial) polarization. Enhanced dielectric, magnetic and conductive behaviors appear in the composite with better intergrain connectivity and larger grain size derived by sol-gel route and three-step sintering method. The effective permittivity contributed by Debye-like dipoles exhibits a value of ~130,000 in three-step sintered composite, which is almost the same as that in conventionally sintered one, but that contributed by M-W response is much smaller in the former. Compared with conventionally prepared samples, the relaxation time ( τ) is 3.476 × 10-6 s, about one order of magnitude smaller, and the dc electrical conductivity is 3.890 × 10-3 S/m, one order of magnitude higher in three-step sintered composite. The minimum dielectric loss reveals almost the same (~0.2) for all samples, but shows distinguishable difference in low-frequency region. Meanwhile, an initial permeability of 84, twice as large as that of conventionally prepared composite and 56 % the value of single-phased NZFO ferrite (~150), and a saturation magnetization of 63.5 emu/g, 32 % higher than that of conventional one and approximately 84 % the value of single-phased NZFO ferrite (~76 emu/g), appear simultaneously in three-step sintered composite with larger grain size and better intergrain connectivity. It is clear that the discovery is helpful for establishing a more explicit view on the physics of multi-functional composite materials, while the composite with optimized microstructure is beneficial to be used as a high-performance material.

Effects of homogenization treatment on recrystallization behavior of 7150 aluminum sheet during post-rolling annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Zhanying; Department of Applied Science, University of Québec at Chicoutimi, Saguenay, QC G7H 2B1; Zhao, Gang

2016-04-15

The effects of two homogenization treatments applied to the direct chill (DC) cast billet on the recrystallization behavior in 7150 aluminum alloy during post-rolling annealing have been investigated using the electron backscatter diffraction (EBSD) technique. Following hot and cold rolling to the sheet, measured orientation maps, the recrystallization fraction and grain size, the misorientation angle and the subgrain size were used to characterize the recovery and recrystallization processes at different annealing temperatures. The results were compared between the conventional one-step homogenization and the new two-step homogenization, with the first step being pretreated at 250 °C. Al{sub 3}Zr dispersoids with highermore » densities and smaller sizes were obtained after the two-step homogenization, which strongly retarded subgrain/grain boundary mobility and inhibited recrystallization. Compared with the conventional one-step homogenized samples, a significantly lower recrystallized fraction and a smaller recrystallized grain size were obtained under all annealing conditions after cold rolling in the two-step homogenized samples. - Highlights: • Effects of two homogenization treatments on recrystallization in 7150 Al sheets • Quantitative study on the recrystallization evolution during post-rolling annealing • Al{sub 3}Zr dispersoids with higher densities and smaller sizes after two-step treatment • Higher recrystallization resistance of 7150 sheets with two-step homogenization.« less

Enhanced performance of wearable piezoelectric nanogenerator fabricated by two-step hydrothermal process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Yu; Lei, Jixue; Yin, Bing

2014-03-17

A simple two-step hydrothermal process was proposed for enhancing the performance of the nanogenerator on flexible and wearable terylene-fabric substrate. With this method, a significant enhancement in output voltage of the nanogenerator from ∼10 mV to 7 V was achieved, comparing with the one by conventional one-step process. In addition, another advantage with the devices synthesized by two-step hydrothermal process was that their output voltages are only sensitive to strain rather than strain rate. The devices with a high output voltage have the ability to power common electric devices and will have important applications in flexible electronics and wearable devices.

Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel

PubMed Central

Yazici, A. Ruya; Yildirim, Zeren; Ertan, Atila; Ozgunaltay, Gül; Dayangac, Berrin; Antonson, Sibel A; Antonson, Donald E

2012-01-01

Objective The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel. Methods: Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocy-cling (5°C–55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at P<.05. Results: All adhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (P<.05). No significant differences in bond strength values were observed between ground and unground enamel for any of the adhesives tested (P=.17). Conclusion: Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested. PMID:22904656

Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel.

PubMed

Yazici, A Ruya; Yildirim, Zeren; Ertan, Atila; Ozgunaltay, Gül; Dayangac, Berrin; Antonson, Sibel A; Antonson, Donald E

2012-07-01

The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel. Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocy-cling (5°C-55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at P<.05. All adhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (P<.05). No significant differences in bond strength values were observed between ground and unground enamel for any of the adhesives tested (P=.17). Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested.

Probability of Two-Step Photoexcitation of Electron from Valence Band to Conduction Band through Doping Level in TiO2.

PubMed

Nishikawa, Masami; Shiroishi, Wataru; Honghao, Hou; Suizu, Hiroshi; Nagai, Hideyuki; Saito, Nobuo

2017-08-17

For an Ir-doped TiO 2 (Ir:TiO 2 ) photocatalyst, we examined the most dominant electron-transfer path for the visible-light-driven photocatalytic performance. The Ir:TiO 2 photocatalyst showed a much higher photocatalytic activity under visible-light irradiation than nondoped TiO 2 after grafting with the cocatalyst of Fe 3+ . For the Ir:TiO 2 photocatalyst, the two-step photoexcitation of an electron from the valence band to the conduction band through the Ir doping level occurred upon visible-light irradiation, as observed by electron spin resonance spectroscopy. The two-step photoexcitation through the doping level was found to be a more stable process with a lower recombination rate of hole-electron pairs than the two-step photoexcitation process through an oxygen vacancy. Once electrons are photoexcited to the conduction band by the two-step excitation, the electrons can easily transfer to the surface because the conduction band is a continuous electron path, whereas the electrons photoexcited at only the doping level could not easily transfer to the surface because of the discontinuity of this path. The observed two-step photoexcitation from the valence band to the conduction band through the doping level significantly contributes to the enhancement of the photocatalytic performance.

Conceptual Models in Health Informatics Research: A Literature Review and Suggestions for Development.

PubMed

Gray, Kathleen; Sockolow, Paulina

2016-02-24

Contributing to health informatics research means using conceptual models that are integrative and explain the research in terms of the two broad domains of health science and information science. However, it can be hard for novice health informatics researchers to find exemplars and guidelines in working with integrative conceptual models. The aim of this paper is to support the use of integrative conceptual models in research on information and communication technologies in the health sector, and to encourage discussion of these conceptual models in scholarly forums. A two-part method was used to summarize and structure ideas about how to work effectively with conceptual models in health informatics research that included (1) a selective review and summary of the literature of conceptual models; and (2) the construction of a step-by-step approach to developing a conceptual model. The seven-step methodology for developing conceptual models in health informatics research explained in this paper involves (1) acknowledging the limitations of health science and information science conceptual models; (2) giving a rationale for one's choice of integrative conceptual model; (3) explicating a conceptual model verbally and graphically; (4) seeking feedback about the conceptual model from stakeholders in both the health science and information science domains; (5) aligning a conceptual model with an appropriate research plan; (6) adapting a conceptual model in response to new knowledge over time; and (7) disseminating conceptual models in scholarly and scientific forums. Making explicit the conceptual model that underpins a health informatics research project can contribute to increasing the number of well-formed and strongly grounded health informatics research projects. This explication has distinct benefits for researchers in training, research teams, and researchers and practitioners in information, health, and other disciplines.

A comparison of artificial compressibility and fractional step methods for incompressible flow computations

NASA Technical Reports Server (NTRS)

Chan, Daniel C.; Darian, Armen; Sindir, Munir

1992-01-01

We have applied and compared the efficiency and accuracy of two commonly used numerical methods for the solution of Navier-Stokes equations. The artificial compressibility method augments the continuity equation with a transient pressure term and allows one to solve the modified equations as a coupled system. Due to its implicit nature, one can have the luxury of taking a large temporal integration step at the expense of higher memory requirement and larger operation counts per step. Meanwhile, the fractional step method splits the Navier-Stokes equations into a sequence of differential operators and integrates them in multiple steps. The memory requirement and operation count per time step are low, however, the restriction on the size of time marching step is more severe. To explore the strengths and weaknesses of these two methods, we used them for the computation of a two-dimensional driven cavity flow with Reynolds number of 100 and 1000, respectively. Three grid sizes, 41 x 41, 81 x 81, and 161 x 161 were used. The computations were considered after the L2-norm of the change of the dependent variables in two consecutive time steps has fallen below 10(exp -5).

EMG synchrony to assess impaired corticomotor control of locomotion after stroke.

PubMed

Lodha, Neha; Chen, Yen-Ting; McGuirk, Theresa E; Fox, Emily J; Kautz, Steven A; Christou, Evangelos A; Clark, David J

2017-12-01

Adapting one's gait pattern requires a contribution from cortical motor commands. Evidence suggests that frequency-based analysis of electromyography (EMG) can be used to detect this cortical contribution. Specifically, increased EMG synchrony between synergistic muscles in the Piper frequency band has been linked to heightened corticomotor contribution to EMG. Stroke-related damage to cerebral motor pathways would be expected to diminish EMG Piper synchrony. The objective of this study is therefore to test the hypothesis that EMG Piper synchrony is diminished in the paretic leg relative to nonparetic and control legs, particularly during a long-step task of walking adaptability. Twenty adults with post-stroke hemiparesis and seventeen healthy controls participated in this study. EMG Piper synchrony increased more for the control legs compare to the paretic legs when taking a non-paretic long step (5.02±3.22% versus 0.86±2.62%), p<0.01) and when taking a paretic long step (2.04±1.98% versus 0.70±2.34%, p<0.05). A similar but non-significant trend was evident when comparing non-paretic and paretic legs. No statistically significant differences in EMG Piper synchrony were found between legs for typical walking. EMG Piper synchrony was positively associated with walking speed and step length within the stroke group. These findings support the assertion that EMG Piper synchrony indicates corticomotor contribution to walking. Published by Elsevier Ltd.

Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks

PubMed Central

Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

2016-01-01

This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

PubMed

Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

2016-05-15

Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Curing mode of universal adhesives affects the bond strength of resin cements to dentin].

PubMed

Fu, Z R; Tian, F C; Zhang, L; Han, B; Wang, X Y

2017-02-18

To determine the effects of curing mode of one-step and two-step universal adhesives on the micro-tensile bond strength (μTBS) of different dual-cure resin cements to dentin. One-step universal adhesive Single Bond Universal (SBU), and two-step universal adhesive OptiBond Versa (VSA) were chosen as the subjects, one-step self-etching adhesive OptiBond All in One (AIO) and two-step self-etching adhesive Clearfil SE Bond (SEB) were control groups, and two dual-cure resin cements RelyX Ultimate (RLX) and Nexus 3 Universal (NX3) were used in this study. In this study, 80 extracted human molars were selected and the dentin surface was exposed using diamond saw. The teeth were divided into 16 groups according to the adhesives (AIO, SBU, SEB, VSA), cure modes of adhesives (light cure, non-light cure) and resin cements (RLX, NX3). The adhesives were applied on the dentin surface following the instruction and whether light cured or not, then the resin cements were applied on the adhesives with 1 mm thickness and light cured (650 mW/cm(2) for 20 s. A resin was built up (5 mm) on the cements and light cured layer by layer. After water storage for 24 h, the specimens were cut into resin-cement-dentin strips with a cross sectional area of 1 mm×1 mm and the μTBS was measured. Regarding one-step universal adhesive (SBU) light cured, the μTBS with RLX [(35.45±7.04) MPa] or NX3 [(26.84±10.39) MPa] were higher than SBU non-light cured with RLX [(17.93±8.93) MPa)] or NX3 [(10.07±5.89) MPa, P<0.001]. Compared with AIO, light-cured SBU combined with RLX presented higher μTBS than AIO group [(35.45±7.04) MPa vs. (24.86±8.42) MPa, P<0.05]. When SBU was not lighted, the μTBS was lower than AIO [(17.93±8.93) MPa vs. (22.28±7.57) MPa, P<0.05]. For two-step universal adhesive (VSA) and control adhesive (SEB), curing mode did not affect the μTBS when used with either RLX or NX3 (25.98-32.24 MPa, P>0.05). Curing mode of one-step universal adhesive may affect the μTBS between dual-cure resin cements and dentin, while for two-step universal adhesive, the curing mode and the type of resin cements did not influence the μTBS.

Subspace aware recovery of low rank and jointly sparse signals

PubMed Central

Biswas, Sampurna; Dasgupta, Soura; Mudumbai, Raghuraman; Jacob, Mathews

2017-01-01

We consider the recovery of a matrix X, which is simultaneously low rank and joint sparse, from few measurements of its columns using a two-step algorithm. Each column of X is measured using a combination of two measurement matrices; one which is the same for every column, while the the second measurement matrix varies from column to column. The recovery proceeds by first estimating the row subspace vectors from the measurements corresponding to the common matrix. The estimated row subspace vectors are then used to recover X from all the measurements using a convex program of joint sparsity minimization. Our main contribution is to provide sufficient conditions on the measurement matrices that guarantee the recovery of such a matrix using the above two-step algorithm. The results demonstrate quite significant savings in number of measurements when compared to the standard multiple measurement vector (MMV) scheme, which assumes same time invariant measurement pattern for all the time frames. We illustrate the impact of the sampling pattern on reconstruction quality using breath held cardiac cine MRI and cardiac perfusion MRI data, while the utility of the algorithm to accelerate the acquisition is demonstrated on MR parameter mapping. PMID:28630889

A hybrid-perturbation-Galerkin technique which combines multiple expansions

NASA Technical Reports Server (NTRS)

Geer, James F.; Andersen, Carl M.

1989-01-01

A two-step hybrid perturbation-Galerkin method for the solution of a variety of differential equations type problems is found to give better results when multiple perturbation expansions are employed. The method assumes that there is parameter in the problem formulation and that a perturbation method can be sued to construct one or more expansions in this perturbation coefficient functions multiplied by computed amplitudes. In step one, regular and/or singular perturbation methods are used to determine the perturbation coefficient functions. The results of step one are in the form of one or more expansions each expressed as a sum of perturbation coefficient functions multiplied by a priori known gauge functions. In step two the classical Bubnov-Galerkin method uses the perturbation coefficient functions computed in step one to determine a set of amplitudes which replace and improve upon the gauge functions. The hybrid method has the potential of overcoming some of the drawbacks of the perturbation and Galerkin methods as applied separately, while combining some of their better features. The proposed method is applied, with two perturbation expansions in each case, to a variety of model ordinary differential equations problems including: a family of linear two-boundary-value problems, a nonlinear two-point boundary-value problem, a quantum mechanical eigenvalue problem and a nonlinear free oscillation problem. The results obtained from the hybrid methods are compared with approximate solutions obtained by other methods, and the applicability of the hybrid method to broader problem areas is discussed.

Effect of production management on semen quality during long-term storage in different European boar studs.

PubMed

Schulze, M; Kuster, C; Schäfer, J; Jung, M; Grossfeld, R

2018-03-01

The processing of ejaculates is a fundamental step for the fertilizing capacity of boar spermatozoa. The aim of the present study was to identify factors that affect quality of boar semen doses. The production process during 1 day of semen processing in 26 European boar studs was monitored. In each boar stud, nine to 19 randomly selected ejaculates from 372 Pietrain boars were analyzed for sperm motility, acrosome and plasma membrane integrity, mitochondrial activity and thermo-resistance (TRT). Each ejaculate was monitored for production time and temperature for each step in semen processing using the special programmed software SEQU (version 1.7, Minitüb, Tiefenbach, Germany). The dilution of ejaculates with a short-term extender was completed in one step in 10 AI centers (n = 135 ejaculates), in two steps in 11 AI centers (n = 158 ejaculates) and in three steps in five AI centers (n = 79 ejaculates). Results indicated there was a greater semen quality with one-step isothermal dilution compared with the multi-step dilution of AI semen doses (total motility TRT d7: 71.1 ± 19.2%, 64.6 ± 20.0%, 47.1 ± 27.1%; one-step compared with two-step compared with the three-step dilution; P < .05). There was a marked advantage when using the one-step isothermal dilution regarding time management, preservation suitability, stability and stress resistance. One-step dilution caused significant lower holding times of raw ejaculates and reduced the possible risk of making mistakes due to a lower number of processing steps. These results lead to refined recommendations for boar semen processing. Copyright © 2018 Elsevier B.V. All rights reserved.

Variability in source sediment contributions by applying different statistic test for a Pyrenean catchment.

PubMed

Palazón, L; Navas, A

2017-06-01

Information on sediment contribution and transport dynamics from the contributing catchments is needed to develop management plans to tackle environmental problems related with effects of fine sediment as reservoir siltation. In this respect, the fingerprinting technique is an indirect technique known to be valuable and effective for sediment source identification in river catchments. Large variability in sediment delivery was found in previous studies in the Barasona catchment (1509 km 2 , Central Spanish Pyrenees). Simulation results with SWAT and fingerprinting approaches identified badlands and agricultural uses as the main contributors to sediment supply in the reservoir. In this study the <63 μm sediment fraction from the surface reservoir sediments (2 cm) are investigated following the fingerprinting procedure to assess how the use of different statistical procedures affects the amounts of source contributions. Three optimum composite fingerprints were selected to discriminate between source contributions based in land uses/land covers from the same dataset by the application of (1) discriminant function analysis; and its combination (as second step) with (2) Kruskal-Wallis H-test and (3) principal components analysis. Source contribution results were different between assessed options with the greatest differences observed for option using #3, including the two step process: principal components analysis and discriminant function analysis. The characteristics of the solutions by the applied mixing model and the conceptual understanding of the catchment showed that the most reliable solution was achieved using #2, the two step process of Kruskal-Wallis H-test and discriminant function analysis. The assessment showed the importance of the statistical procedure used to define the optimum composite fingerprint for sediment fingerprinting applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Evaluation of shear bond strengths of self-etching and total-etching dental adhesives to enamel and dentin].

PubMed

Yu, Ling; Liu, Jing-Ming; Wang, Xiao-Yan; Gao, Xue-Jun

2009-03-01

To evaluate the shear bond strengths of four dental adhesives in vitro. The facial surfaces of 20 human maxillary incisors were prepared to expose fresh enamel and randomly divided into four groups, in each group 5 teeth were bonded with one adhesives: group A (Clearfil Protect Bond, self-etching two steps), group B (Adper( Prompt, self-etching one step), group C (SwissTEC SL Bond, total-etching two steps), group D (Single Bond, total-etching two steps). Shear bond strengths were determined using an universal testing machine after being stored in distilled water for 24 h at 37 degrees C. The bond strengths to enamel and dentin were (25.33 +/- 2.84) and (26.07 +/- 5.56) MPa in group A, (17.08 +/- 5.13) and (17.93 +/- 4.70) MPa in group B, (33.14 +/- 6.05) and (41.92 +/- 6.25) MPa in group C, (22.51 +/- 6.25) and (21.45 +/- 7.34) MPa in group D. Group C showed the highest and group B the lowest shear bond strength to enamel and dentin among the four groups. The two-step self-etching adhesive showed comparable shear bond strength to some of the total-etching adhesives and higher shear bond strength than one-step self-etching adhesive.

Cross-platform evaluation of commercial real-time SYBR green RT-PCR kits for sensitive and rapid detection of European bat Lyssavirus type 1.

PubMed

Picard-Meyer, Evelyne; Peytavin de Garam, Carine; Schereffer, Jean Luc; Marchal, Clotilde; Robardet, Emmanuelle; Cliquet, Florence

2015-01-01

This study evaluates the performance of five two-step SYBR Green RT-qPCR kits and five one-step SYBR Green qRT-PCR kits using real-time PCR assays. Two real-time thermocyclers showing different throughput capacities were used. The analysed performance evaluation criteria included the generation of standard curve, reaction efficiency, analytical sensitivity, intra- and interassay repeatability as well as the costs and the practicability of kits, and thermocycling times. We found that the optimised one-step PCR assays had a higher detection sensitivity than the optimised two-step assays regardless of the machine used, while no difference was detected in reaction efficiency, R (2) values, and intra- and interreproducibility between the two methods. The limit of detection at the 95% confidence level varied between 15 to 981 copies/µL and 41 to 171 for one-step kits and two-step kits, respectively. Of the ten kits tested, the most efficient kit was the Quantitect SYBR Green qRT-PCR with a limit of detection at 95% of confidence of 20 and 22 copies/µL on the thermocyclers Rotor gene Q MDx and MX3005P, respectively. The study demonstrated the pivotal influence of the thermocycler on PCR performance for the detection of rabies RNA, as well as that of the master mixes.

Preparation and characterization of silica xerogels as carriers for drugs.

PubMed

Czarnobaj, K

2008-11-01

The aim of the present study was to utilize the sol-gel method to synthesize different forms of xerogel matrices for drugs and to investigate how the synthesis conditions and solubility of drugs influence the change of the profile of drug release and the structure of the matrices. Silica xerogels doped with drugs were prepared by the sol-gel method from a hydrolyzed tetraethoxysilane (TEOS) solution containing two model compounds: diclofenac diethylamine, (DD)--a water-soluble drug or ibuprofen, (IB)--a water insoluble drug. Two procedures were used for the synthesis of sol-gel derived materials: one-step procedure (the sol-gel reaction was carried out under acidic or basic conditions) and the two-step procedure (first, hydrolysis of TEOS was carried out under acidic conditions, and then condensation of silanol groups was carried out under basic conditions) in order to obtain samples with altered microstructures. In vitro release studies of drugs revealed a similar release profile in two steps: an initial diffusion-controlled release followed by a slower release rate. In all the cases studied, the released amount of DD was higher and the released time was shorter compared with IB for the same type of matrices. The released amount of drugs from two-step prepared xerogels was always lower than that from one-step base-catalyzed xerogels. One-step acid-catalyzed xerogels proved unsuitable as the carriers for the examined drugs.

Cross-Platform Evaluation of Commercial Real-Time SYBR Green RT-PCR Kits for Sensitive and Rapid Detection of European Bat Lyssavirus Type 1

PubMed Central

Picard-Meyer, Evelyne; Peytavin de Garam, Carine; Schereffer, Jean Luc; Marchal, Clotilde; Robardet, Emmanuelle; Cliquet, Florence

2015-01-01

This study evaluates the performance of five two-step SYBR Green RT-qPCR kits and five one-step SYBR Green qRT-PCR kits using real-time PCR assays. Two real-time thermocyclers showing different throughput capacities were used. The analysed performance evaluation criteria included the generation of standard curve, reaction efficiency, analytical sensitivity, intra- and interassay repeatability as well as the costs and the practicability of kits, and thermocycling times. We found that the optimised one-step PCR assays had a higher detection sensitivity than the optimised two-step assays regardless of the machine used, while no difference was detected in reaction efficiency, R 2 values, and intra- and interreproducibility between the two methods. The limit of detection at the 95% confidence level varied between 15 to 981 copies/µL and 41 to 171 for one-step kits and two-step kits, respectively. Of the ten kits tested, the most efficient kit was the Quantitect SYBR Green qRT-PCR with a limit of detection at 95% of confidence of 20 and 22 copies/µL on the thermocyclers Rotor gene Q MDx and MX3005P, respectively. The study demonstrated the pivotal influence of the thermocycler on PCR performance for the detection of rabies RNA, as well as that of the master mixes. PMID:25785274

Association between the gait pattern characteristics of older people and their two-step test scores.

PubMed

Kobayashi, Yoshiyuki; Ogata, Toru

2018-04-27

The Two-Step test is one of three official tests authorized by the Japanese Orthopedic Association to evaluate the risk of locomotive syndrome (a condition of reduced mobility caused by an impairment of the locomotive organs). It has been reported that the Two-Step test score has a good correlation with one's walking ability; however, its association with the gait pattern of older people during normal walking is still unknown. Therefore, this study aims to clarify the associations between the gait patterns of older people observed during normal walking and their Two-Step test scores. We analyzed the whole waveforms obtained from the lower-extremity joint angles and joint moments of 26 older people in various stages of locomotive syndrome using principal component analysis (PCA). The PCA was conducted using a 260 × 2424 input matrix constructed from the participants' time-normalized pelvic and right-lower-limb-joint angles along three axes (ten trials of 26 participants, 101 time points, 4 angles, 3 axes, and 2 variable types per trial). The Pearson product-moment correlation coefficient between the scores of the principal component vectors (PCVs) and the scores of the Two-Step test revealed that only one PCV (PCV 2) among the 61 obtained relevant PCVs is significantly related to the score of the Two-Step test. We therefore concluded that the joint angles and joint moments related to PCV 2-ankle plantar-flexion, ankle plantar-flexor moments during the late stance phase, ranges of motion and moments on the hip, knee, and ankle joints in the sagittal plane during the entire stance phase-are the motions associated with the Two-Step test.

Force-related neuronal activity in two regions of the primate ventral premotor cortex.

PubMed

Hepp-Reymond, M C; Hüsler, E J; Maier, M A; Ql, H X

1994-05-01

Neuronal activity was recorded in the ventral premotor cortex of one monkey (Macaca fascicularis) trained to exert finely graded forces with thumb and index finger on a force sensor in a visuomotor step-tracking paradigm. Trials with two or three consecutive ramp-and-hold force steps were presented randomly. Most neurons displayed similar discharge patterns in the two- and three-step trials and were assigned to one of the following classes: phasic, phasic-tonic, tonic, decreasing, and mixed. For more than 50% of the neurons with tonic activity, positive or negative correlations between firing rate and force were statistically significant. The indices of force sensitivity were on average higher for the two-step than for the three-step trials, indicating that the correlations yielded linearity over only a limited force range. The force-related cells were located in two regions of the ventral premotor cortex. One group was ying rostrally within the inferior limb of the arcuate sulcus, from which microstimulation elicited movements of fingers and hand. In the other more caudal region, adjacent to the finger region of primary motor cortex, microstimulation was rarely effective, but all neurons had clear peripheral receptive fields on finger and hand. The data indicate that two populations of neurons, located in the ventral premotor cortex, are related to movement execution. Effective microstimulation also suggests that one of the populations has fairly direct access to the spinal motor apparatus.

The tyrosine phosphatase STEP: implications in schizophrenia and the molecular mechanism underlying antipsychotic medications

PubMed Central

Carty, N C; Xu, J; Kurup, P; Brouillette, J; Goebel-Goody, S M; Austin, D R; Yuan, P; Chen, G; Correa, P R; Haroutunian, V; Pittenger, C; Lombroso, P J

2012-01-01

Glutamatergic signaling through N-methyl-D-aspartate receptors (NMDARs) is required for synaptic plasticity. Disruptions in glutamatergic signaling are proposed to contribute to the behavioral and cognitive deficits observed in schizophrenia (SZ). One possible source of compromised glutamatergic function in SZ is decreased surface expression of GluN2B-containing NMDARs. STEP61 is a brain-enriched protein tyrosine phosphatase that dephosphorylates a regulatory tyrosine on GluN2B, thereby promoting its internalization. Here, we report that STEP61 levels are significantly higher in the postmortem anterior cingulate cortex and dorsolateral prefrontal cortex of SZ patients, as well as in mice treated with the psychotomimetics MK-801 and phencyclidine (PCP). Accumulation of STEP61 after MK-801 treatment is due to a disruption in the ubiquitin proteasome system that normally degrades STEP61. STEP knockout mice are less sensitive to both the locomotor and cognitive effects of acute and chronic administration of PCP, supporting the functional relevance of increased STEP61 levels in SZ. In addition, chronic treatment of mice with both typical and atypical antipsychotic medications results in a protein kinase A-mediated phosphorylation and inactivation of STEP61 and, consequently, increased surface expression of GluN1/GluN2B receptors. Taken together, our findings suggest that STEP61 accumulation may contribute to the pathophysiology of SZ. Moreover, we show a mechanistic link between neuroleptic treatment, STEP61 inactivation and increased surface expression of NMDARs, consistent with the glutamate hypothesis of SZ. PMID:22781170

Preschool Teachers' Skills in Teaching Music: Two Steps Forward One Step Back

ERIC Educational Resources Information Center

Ehrlin, Anna; Wallerstedt, Cecilia

2014-01-01

This study investigates through observations and interviews what importance further education has for preschool teachers' practice in two music-profiled preschool and their way of conceptualising it. A distinction between music as a method for teaching, on the one hand, and as a content of knowledge, on the other, is used in the analysis. The…

On salesmen and tourists: Two-step optimization in deterministic foragers

NASA Astrophysics Data System (ADS)

Maya, Miguel; Miramontes, Octavio; Boyer, Denis

2017-02-01

We explore a two-step optimization problem in random environments, the so-called restaurant-coffee shop problem, where a walker aims at visiting the nearest and better restaurant in an area and then move to the nearest and better coffee-shop. This is an extension of the Tourist Problem, a one-step optimization dynamics that can be viewed as a deterministic walk in a random medium. A certain amount of heterogeneity in the values of the resources to be visited causes the emergence of power-laws distributions for the steps performed by the walker, similarly to a Lévy flight. The fluctuations of the step lengths tend to decrease as a consequence of multiple-step planning, thus reducing the foraging uncertainty. We find that the first and second steps of each planned movement play very different roles in heterogeneous environments. The two-step process improves only slightly the foraging efficiency compared to the one-step optimization, at a much higher computational cost. We discuss the implications of these findings for animal and human mobility, in particular in relation to the computational effort that informed agents should deploy to solve search problems.

Dimensional Accuracy of Hydrophilic and Hydrophobic VPS Impression Materials Using Different Impression Techniques - An Invitro Study

PubMed Central

Pilla, Ajai; Pathipaka, Suman

2016-01-01

Introduction The dimensional stability of the impression material could have an influence on the accuracy of the final restoration. Vinyl Polysiloxane Impression materials (VPS) are most frequently used as the impression material in fixed prosthodontics. As VPS is hydrophobic when it is poured with gypsum products, manufacturers added intrinsic surfactants and marketed as hydrophilic VPS. These hydrophilic VPS have shown increased wettability with gypsum slurries. VPS are available in different viscosities ranging from very low to very high for usage under different impression techniques. Aim To compare the dimensional accuracy of hydrophilic VPS and hydrophobic VPS using monophase, one step and two step putty wash impression techniques. Materials and Methods To test the dimensional accuracy of the impression materials a stainless steel die was fabricated as prescribed by ADA specification no. 19 for elastomeric impression materials. A total of 60 impressions were made. The materials were divided into two groups, Group1 hydrophilic VPS (Aquasil) and Group 2 hydrophobic VPS (Variotime). These were further divided into three subgroups A, B, C for monophase, one-step and two-step putty wash technique with 10 samples in each subgroup. The dimensional accuracy of the impressions was evaluated after 24 hours using vertical profile projector with lens magnification range of 20X-125X illumination. The study was analyzed through one-way ANOVA, post-hoc Tukey HSD test and unpaired t-test for mean comparison between groups. Results Results showed that the three different impression techniques (monophase, 1-step, 2-step putty wash techniques) did cause significant change in dimensional accuracy between hydrophilic VPS and hydrophobic VPS impression materials. One-way ANOVA disclosed, mean dimensional change and SD for hydrophilic VPS varied between 0.56% and 0.16%, which were low, suggesting hydrophilic VPS was satisfactory with all three impression techniques. However, mean dimensional change and SD for hydrophobic VPS were much higher with monophase, mere increase for 1-step and 2-step, than the standard steel die (p<0.05). Unpaired t-test displayed that hydrophilic VPS judged satisfactory compared to hydrophobic VPS among 1-step and 2-step impression technique. Conclusion Within the limitations of this study, it can be concluded that hydrophilic Vinyl polysiloxane was more dimensionally accurate than hydrophobic Vinyl polysiloxane using monophase, one step and two step putty wash impression techniques under moist conditions. PMID:27042587

Two steps forward, one step back? A commentary on the disease-specific core sets of the International Classification of Functioning, Disability and Health (ICF).

PubMed

McIntyre, Anne; Tempest, Stephanie

2007-09-30

The International Classification of Functioning, Disability and Health (ICF) has been received favourably by health care professionals, disability rights organizations and proponents of the social model of disability. The success of the ICF largely depends on its uptake in practice and is considered unwieldy in its full format. To enhance the application of the ICF in practice, disease and site-specific core sets have been developed. The objective of this paper is to stimulate thought and discussion about the place of the ICF core sets in rehabilitation practice. The authors' review of the literature uses the ICF core sets (especially stroke), to debate if the ICF is at risk of taking two steps forward, one step back in its holistic portrayal of health. ICF disease specific core sets could be seen as taking two steps forward to enhance the user friendliness of the ICF and evidence-based practice in rehabilitation. However, there is a danger of taking one step back in reverting to a disease-specific classification. It is too early to conclude the efficacy of the disease-specific core sets, but there is an opportunity to debate where the next steps may lead.

Highly Efficient Production of Soluble Proteins from Insoluble Inclusion Bodies by a Two-Step-Denaturing and Refolding Method

PubMed Central

Zhang, Yan; Zhang, Ting; Feng, Yanye; Lu, Xiuxiu; Lan, Wenxian; Wang, Jufang; Wu, Houming; Cao, Chunyang; Wang, Xiaoning

2011-01-01

The production of recombinant proteins in a large scale is important for protein functional and structural studies, particularly by using Escherichia coli over-expression systems; however, approximate 70% of recombinant proteins are over-expressed as insoluble inclusion bodies. Here we presented an efficient method for generating soluble proteins from inclusion bodies by using two steps of denaturation and one step of refolding. We first demonstrated the advantages of this method over a conventional procedure with one denaturation step and one refolding step using three proteins with different folding properties. The refolded proteins were found to be active using in vitro tests and a bioassay. We then tested the general applicability of this method by analyzing 88 proteins from human and other organisms, all of which were expressed as inclusion bodies. We found that about 76% of these proteins were refolded with an average of >75% yield of soluble proteins. This “two-step-denaturing and refolding” (2DR) method is simple, highly efficient and generally applicable; it can be utilized to obtain active recombinant proteins for both basic research and industrial purposes. PMID:21829569

Small-scale seismic inversion using surface waves extracted from noise cross correlation.

PubMed

Gouédard, Pierre; Roux, Philippe; Campillo, Michel

2008-03-01

Green's functions can be retrieved between receivers from the correlation of ambient seismic noise or with an appropriate set of randomly distributed sources. This principle is demonstrated in small-scale geophysics using noise sources generated by human steps during a 10-min walk in the alignment of a 14-m-long accelerometer line array. The time-domain correlation of the records yields two surface wave modes extracted from the Green's function between each pair of accelerometers. A frequency-wave-number Fourier analysis yields each mode contribution and their dispersion curve. These dispersion curves are then inverted to provide the one-dimensional shear velocity of the near surface.

A framework for conducting mechanistic based reliability assessments of components operating in complex systems

NASA Astrophysics Data System (ADS)

Wallace, Jon Michael

2003-10-01

Reliability prediction of components operating in complex systems has historically been conducted in a statistically isolated manner. Current physics-based, i.e. mechanistic, component reliability approaches focus more on component-specific attributes and mathematical algorithms and not enough on the influence of the system. The result is that significant error can be introduced into the component reliability assessment process. The objective of this study is the development of a framework that infuses the needs and influence of the system into the process of conducting mechanistic-based component reliability assessments. The formulated framework consists of six primary steps. The first three steps, identification, decomposition, and synthesis, are primarily qualitative in nature and employ system reliability and safety engineering principles to construct an appropriate starting point for the component reliability assessment. The following two steps are the most unique. They involve a step to efficiently characterize and quantify the system-driven local parameter space and a subsequent step using this information to guide the reduction of the component parameter space. The local statistical space quantification step is accomplished using two proposed multivariate probability models: Multi-Response First Order Second Moment and Taylor-Based Inverse Transformation. Where existing joint probability models require preliminary distribution and correlation information of the responses, these models combine statistical information of the input parameters with an efficient sampling of the response analyses to produce the multi-response joint probability distribution. Parameter space reduction is accomplished using Approximate Canonical Correlation Analysis (ACCA) employed as a multi-response screening technique. The novelty of this approach is that each individual local parameter and even subsets of parameters representing entire contributing analyses can now be rank ordered with respect to their contribution to not just one response, but the entire vector of component responses simultaneously. The final step of the framework is the actual probabilistic assessment of the component. Although the same multivariate probability tools employed in the characterization step can be used for the component probability assessment, variations of this final step are given to allow for the utilization of existing probabilistic methods such as response surface Monte Carlo and Fast Probability Integration. The overall framework developed in this study is implemented to assess the finite-element based reliability prediction of a gas turbine airfoil involving several failure responses. Results of this implementation are compared to results generated using the conventional 'isolated' approach as well as a validation approach conducted through large sample Monte Carlo simulations. The framework resulted in a considerable improvement to the accuracy of the part reliability assessment and an improved understanding of the component failure behavior. Considerable statistical complexity in the form of joint non-normal behavior was found and accounted for using the framework. Future applications of the framework elements are discussed.

Aqueous solvation from the water perspective.

PubMed

Ahmed, Saima; Pasti, Andrea; Fernández-Terán, Ricardo J; Ciardi, Gustavo; Shalit, Andrey; Hamm, Peter

2018-06-21

The response of water re-solvating a charge-transfer dye (deprotonated Coumarin 343) after photoexcitation has been measured by means of transient THz spectroscopy. Two steps of increasing THz absorption are observed, a first ∼10 ps step on the time scale of Debye relaxation of bulk water and a much slower step on a 3.9 ns time scale, the latter of which reflecting heating of the bulk solution upon electronic relaxation of the dye molecules from the S 1 back into the S 0 state. As an additional reference experiment, the hydroxyl vibration of water has been excited directly by a short IR pulse, establishing that the THz signal measures an elevated temperature within ∼1 ps. This result shows that the first step upon dye excitation (10 ps) is not limited by the response time of the THz signal; it rather reflects the reorientation of water molecules in the solvation layer. The apparent discrepancy between the relatively slow reorientation time and the general notion that water is among the fastest solvents with a solvation time in the sub-picosecond regime is discussed. Furthermore, non-equilibrium molecular dynamics simulations have been performed, revealing a close-to-quantitative agreement with experiment, which allows one to disentangle the contribution of heating to the overall THz response from that of water orientation.

Contributions of dopamine-related genes and environmental factors to highly sensitive personality: a multi-step neuronal system-level approach.

PubMed

Chen, Chunhui; Chen, Chuansheng; Moyzis, Robert; Stern, Hal; He, Qinghua; Li, He; Li, Jin; Zhu, Bi; Dong, Qi

2011-01-01

Traditional behavioral genetic studies (e.g., twin, adoption studies) have shown that human personality has moderate to high heritability, but recent molecular behavioral genetic studies have failed to identify quantitative trait loci (QTL) with consistent effects. The current study adopted a multi-step approach (ANOVA followed by multiple regression and permutation) to assess the cumulative effects of multiple QTLs. Using a system-level (dopamine system) genetic approach, we investigated a personality trait deeply rooted in the nervous system (the Highly Sensitive Personality, HSP). 480 healthy Chinese college students were given the HSP scale and genotyped for 98 representative polymorphisms in all major dopamine neurotransmitter genes. In addition, two environment factors (stressful life events and parental warmth) that have been implicated for their contributions to personality development were included to investigate their relative contributions as compared to genetic factors. In Step 1, using ANOVA, we identified 10 polymorphisms that made statistically significant contributions to HSP. In Step 2, these polymorphism's main effects and interactions were assessed using multiple regression. This model accounted for 15% of the variance of HSP (p<0.001). Recent stressful life events accounted for an additional 2% of the variance. Finally, permutation analyses ascertained the probability of obtaining these findings by chance to be very low, p ranging from 0.001 to 0.006. Dividing these loci by the subsystems of dopamine synthesis, degradation/transport, receptor and modulation, we found that the modulation and receptor subsystems made the most significant contribution to HSP. The results of this study demonstrate the utility of a multi-step neuronal system-level approach in assessing genetic contributions to individual differences in human behavior. It can potentially bridge the gap between the high heritability estimates based on traditional behavioral genetics and the lack of reproducible genetic effects observed currently from molecular genetic studies.

Contributions of Dopamine-Related Genes and Environmental Factors to Highly Sensitive Personality: A Multi-Step Neuronal System-Level Approach

PubMed Central

Chen, Chunhui; Chen, Chuansheng; Moyzis, Robert; Stern, Hal; He, Qinghua; Li, He; Li, Jin; Zhu, Bi; Dong, Qi

2011-01-01

Traditional behavioral genetic studies (e.g., twin, adoption studies) have shown that human personality has moderate to high heritability, but recent molecular behavioral genetic studies have failed to identify quantitative trait loci (QTL) with consistent effects. The current study adopted a multi-step approach (ANOVA followed by multiple regression and permutation) to assess the cumulative effects of multiple QTLs. Using a system-level (dopamine system) genetic approach, we investigated a personality trait deeply rooted in the nervous system (the Highly Sensitive Personality, HSP). 480 healthy Chinese college students were given the HSP scale and genotyped for 98 representative polymorphisms in all major dopamine neurotransmitter genes. In addition, two environment factors (stressful life events and parental warmth) that have been implicated for their contributions to personality development were included to investigate their relative contributions as compared to genetic factors. In Step 1, using ANOVA, we identified 10 polymorphisms that made statistically significant contributions to HSP. In Step 2, these polymorphism's main effects and interactions were assessed using multiple regression. This model accounted for 15% of the variance of HSP (p<0.001). Recent stressful life events accounted for an additional 2% of the variance. Finally, permutation analyses ascertained the probability of obtaining these findings by chance to be very low, p ranging from 0.001 to 0.006. Dividing these loci by the subsystems of dopamine synthesis, degradation/transport, receptor and modulation, we found that the modulation and receptor subsystems made the most significant contribution to HSP. The results of this study demonstrate the utility of a multi-step neuronal system-level approach in assessing genetic contributions to individual differences in human behavior. It can potentially bridge the gap between the high heritability estimates based on traditional behavioral genetics and the lack of reproducible genetic effects observed currently from molecular genetic studies. PMID:21765900

Highly efficient one-pot/one-step synthesis of multiblock copolymers from three-component polymerization of carbon dioxide, epoxide and lactone.

PubMed

Li, Yang; Hong, Jiali; Wei, Renjian; Zhang, Yingying; Tong, Zaizai; Zhang, Xinghong; Du, Binyang; Xu, Junting; Fan, Zhiqiang

2015-02-01

It is a long-standing challenge to combine mixed monomers into multiblock copolymer (MBC) in a one-pot/one-step polymerization manner. We report the first example of MBC with biodegradable polycarbonate and polyester blocks that were synthesized from highly efficient one-pot/one-step polymerization of cyclohexene oxide (CHO), CO 2 and ε-caprolactone (ε-CL) in the presence of zinc-cobalt double metal cyanide complex and stannous octoate. In this protocol, two cross-chain exchange reactions (CCER) occurred at dual catalysts respectively and connected two independent chain propagation procedures ( i.e. , polycarbonate formation and polyester formation) simultaneously in a block-by-block manner, affording MBC without tapering structure. The multiblock structure of MBC was determined by the rate ratio of CCER to the two chain propagations and could be simply tuned by various kinetic factors. This protocol is also of significance due to partial utilization of renewable CO 2 and improved mechanical properties of the resultant MBC.

[Investigation of stages of chemical leaching and biooxidation during the extraction of gold from sulfide concentrates].

PubMed

Murav'ev, M I; Fomchenko, N V; Kondrat'eva, T V

2015-01-01

We examined the chemical leaching and biooxidation stages in a two-stage biooxidation process of an auriferous sulfide concentrate containing pyrrhotite, arsenopyrite and pyrite. Chemical leaching of the concentrate (slurry density at 200 g/L) by ferric sulfate biosolvent (initial concentration at 35.6 g/L), which was obtained by microbial oxidation of ferrous sulfate for 2 hours at 70°C at pH 1.4, was allowed to oxidize 20.4% ofarsenopyrite and 52.1% of sulfur. The most effective biooxidation of chemically leached concentrate was observed at 45°C in the presence of yeast extract. Oxidation of the sulfide concentrate in a two-step process proceeded more efficiently than in one-step. In a two-step mode, gold extraction from the precipitate was 10% higher and the content of elemental sulfur was two times lower than in a one-step process.

Development and external validation of new ultrasound-based mathematical models for preoperative prediction of high-risk endometrial cancer.

PubMed

Van Holsbeke, C; Ameye, L; Testa, A C; Mascilini, F; Lindqvist, P; Fischerova, D; Frühauf, F; Fransis, S; de Jonge, E; Timmerman, D; Epstein, E

2014-05-01

To develop and validate strategies, using new ultrasound-based mathematical models, for the prediction of high-risk endometrial cancer and compare them with strategies using previously developed models or the use of preoperative grading only. Women with endometrial cancer were prospectively examined using two-dimensional (2D) and three-dimensional (3D) gray-scale and color Doppler ultrasound imaging. More than 25 ultrasound, demographic and histological variables were analyzed. Two logistic regression models were developed: one 'objective' model using mainly objective variables; and one 'subjective' model including subjective variables (i.e. subjective impression of myometrial and cervical invasion, preoperative grade and demographic variables). The following strategies were validated: a one-step strategy using only preoperative grading and two-step strategies using preoperative grading as the first step and one of the new models, subjective assessment or previously developed models as a second step. One-hundred and twenty-five patients were included in the development set and 211 were included in the validation set. The 'objective' model retained preoperative grade and minimal tumor-free myometrium as variables. The 'subjective' model retained preoperative grade and subjective assessment of myometrial invasion. On external validation, the performance of the new models was similar to that on the development set. Sensitivity for the two-step strategy with the 'objective' model was 78% (95% CI, 69-84%) at a cut-off of 0.50, 82% (95% CI, 74-88%) for the strategy with the 'subjective' model and 83% (95% CI, 75-88%) for that with subjective assessment. Specificity was 68% (95% CI, 58-77%), 72% (95% CI, 62-80%) and 71% (95% CI, 61-79%) respectively. The two-step strategies detected up to twice as many high-risk cases as preoperative grading only. The new models had a significantly higher sensitivity than did previously developed models, at the same specificity. Two-step strategies with 'new' ultrasound-based models predict high-risk endometrial cancers with good accuracy and do this better than do previously developed models. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

Assistive devices alter gait patterns in Parkinson disease: advantages of the four-wheeled walker.

PubMed

Kegelmeyer, Deb A; Parthasarathy, Sowmya; Kostyk, Sandra K; White, Susan E; Kloos, Anne D

2013-05-01

Gait abnormalities are a hallmark of Parkinson's disease (PD) and contribute to fall risk. Therapy and exercise are often encouraged to increase mobility and decrease falls. As disease symptoms progress, assistive devices are often prescribed. There are no guidelines for choosing appropriate ambulatory devices. This unique study systematically examined the impact of a broad range of assistive devices on gait measures during walking in both a straight path and around obstacles in individuals with PD. Quantitative gait measures, including velocity, stride length, percent swing and double support time, and coefficients of variation were assessed in 27 individuals with PD with or without one of six different devices including canes, standard and wheeled walkers (two, four or U-Step). Data were collected using the GAITRite and on a figure-of-eight course. All devices, with the exception of four-wheeled and U-Step walkers significantly decreased gait velocity. The four-wheeled walker resulted in less variability in gait measures and had less impact on spontaneous unassisted gait patterns. The U-Step walker exhibited the highest variability across all parameters followed by the two-wheeled and standard walkers. Higher variability has been correlated with increased falls. Though subjects performed better on a figure-of-eight course using either the four-wheeled or the U-Step walker, the four-wheeled walker resulted in the most consistent improvement in overall gait variables. Laser light use on a U-Step walker did not improve gait measures or safety in figure-of-eight compared to other devices. Of the devices tested, the four-wheeled-walker offered the most consistent advantages for improving mobility and safety. Copyright © 2012 Elsevier B.V. All rights reserved.

Dynamical interpretation of conditional patterns

NASA Technical Reports Server (NTRS)

Adrian, R. J.; Moser, R. D.; Moin, P.

1988-01-01

While great progress is being made in characterizing the 3-D structure of organized turbulent motions using conditional averaging analysis, there is a lack of theoretical guidance regarding the interpretation and utilization of such information. Questions concerning the significance of the structures, their contributions to various transport properties, and their dynamics cannot be answered without recourse to appropriate dynamical governing equations. One approach which addresses some of these questions uses the conditional fields as initial conditions and calculates their evolution from the Navier-Stokes equations, yielding valuable information about stability, growth, and longevity of the mean structure. To interpret statistical aspects of the structures, a different type of theory which deals with the structures in the context of their contributions to the statistics of the flow is needed. As a first step toward this end, an effort was made to integrate the structural information from the study of organized structures with a suitable statistical theory. This is done by stochastically estimating the two-point conditional averages that appear in the equation for the one-point probability density function, and relating the structures to the conditional stresses. Salient features of the estimates are identified, and the structure of the one-point estimates in channel flow is defined.

A Two-Step Integrated Theory of Everything (TOE)

NASA Astrophysics Data System (ADS)

Colella, Antonio

2017-01-01

Two opposing TOE visions are my Two-Step (physics/math) and Hawking's single math step. My Two-Step should replace the single step because of the latter's near zero results after a century of attempts. My physics step had 3 goals. First ``Everything'' was defined as 20 interrelated amplified theories (e.g. string, Higgs forces, spontaneous symmetry breaking, particle decays, dark matter, dark energy, stellar black holes) and their intimate physical interrelationships. Amplifications of Higgs forces theory (e.g. matter particles and their associated Higgs forces were one and inseparable, spontaneous symmetry breaking was bidirectional and caused by high temperatures not Higgs forces, and sum of 8 Higgs forces of 8 permanent matter particles was dark energy) were key to my Two-Step TOE. The second goal answered all outstanding physics questions: what were Higgs forces, dark energy, dark matter, stellar black holes, our universe's creation, etc.? The third goal provided correct inputs for the two part second math step, an E8 Lie algebra for particles and an N-body cosmology simulation (work in progress). Scientific advancement occurs only if the two opposing TOEs are openly discussed/debated.

Resonant frequency calculations using a hybrid perturbation-Galerkin technique

NASA Technical Reports Server (NTRS)

Geer, James F.; Andersen, Carl M.

1991-01-01

A two-step hybrid perturbation Galerkin technique is applied to the problem of determining the resonant frequencies of one or several degree of freedom nonlinear systems involving a parameter. In one step, the Lindstedt-Poincare method is used to determine perturbation solutions which are formally valid about one or more special values of the parameter (e.g., for large or small values of the parameter). In step two, a subset of the perturbation coordinate functions determined in step one is used in Galerkin type approximation. The technique is illustrated for several one degree of freedom systems, including the Duffing and van der Pol oscillators, as well as for the compound pendulum. For all of the examples considered, it is shown that the frequencies obtained by the hybrid technique using only a few terms from the perturbation solutions are significantly more accurate than the perturbation results on which they are based, and they compare very well with frequencies obtained by purely numerical methods.

[PLASMALEMMAL ION TRANSPORT IN POLLEN TUBES IS REGULATED BY HYDROGEN PEROXIDE].

PubMed

Maksimov, N M; Breygina, M A; Yermakov, I P

2015-01-01

Pollen tube growth is a key step in the life cycle of seed plants, which defines the success of sexual reproduction. One of the most important contributions to this process is made by ion transport through plasmalemma, which is tightly coordinated in time and space. Different classes of signaling molecules are involved in the regulation of transmembrane ion transport including reactive oxygen species as it has been recently demonstrated. Here, using subprotoplasts isolated from pollen tubes, we have demonstrated a connection between hydrogen peroxide, on one side, and two groups of targets on the plasma membrane, on the other side: nifedipine-sensitive Ca(2+)-permeable channels and transport systems controlling membrane potential. H2O2 interaction with these targets causes the increase in cytoplasmic Ca2+ concentration and plasmalemma hyperpolarization. One of the consequences of target modification was acceleration of cell wall regeneration.

Resolving the infection process reveals striking differences in the contribution of environment, genetics and phylogeny to host-parasite interactions.

PubMed

Duneau, David; Luijckx, Pepijn; Ben-Ami, Frida; Laforsch, Christian; Ebert, Dieter

2011-02-22

Infection processes consist of a sequence of steps, each critical for the interaction between host and parasite. Studies of host-parasite interactions rarely take into account the fact that different steps might be influenced by different factors and might, therefore, make different contributions to shaping coevolution. We designed a new method using the Daphnia magna - Pasteuria ramosa system, one of the rare examples where coevolution has been documented, in order to resolve the steps of the infection and analyse the factors that influence each of them. Using the transparent Daphnia hosts and fluorescently-labelled spores of the bacterium P. ramosa, we identified a sequence of infection steps: encounter between parasite and host; activation of parasite dormant spores; attachment of spores to the host; and parasite proliferation inside the host. The chances of encounter had been shown to depend on host genotype and environment. We tested the role of genetic and environmental factors in the newly described activation and attachment steps. Hosts of different genotypes, gender and species were all able to activate endospores of all parasite clones tested in different environments; suggesting that the activation cue is phylogenetically conserved. We next established that parasite attachment occurs onto the host oesophagus independently of host species, gender and environmental conditions. In contrast to spore activation, attachment depended strongly on the combination of host and parasite genotypes. Our results show that different steps are influenced by different factors. Host-type-independent spore activation suggests that this step can be ruled out as a major factor in Daphnia-Pasteuria coevolution. On the other hand, we show that the attachment step is crucial for the pronounced genetic specificities of this system. We suggest that this one step can explain host population structure and could be a key force behind coevolutionary cycles. We discuss how different steps can explain different aspects of the coevolutionary dynamics of the system: the properties of the attachment step, explaining the rapid evolution of infectivity and the properties of later parasite proliferation explaining the evolution of virulence. Our study underlines the importance of resolving the infection process in order to better understand host-parasite interactions.

Pelvic step: the contribution of horizontal pelvis rotation to step length in young healthy adults walking on a treadmill.

PubMed

Liang, Bo Wei; Wu, Wen Hua; Meijer, Onno G; Lin, Jian Hua; Lv, Go Rong; Lin, Xiao Cong; Prins, Maarten R; Hu, Hai; van Dieën, Jaap H; Bruijn, Sjoerd M

2014-01-01

Transverse plane pelvis rotations during walking may be regarded as the "first determinant of gait". This would assume that pelvis rotations increase step length, and thereby reduce the vertical movements of the centre of mass-"the pelvic step". We analysed the pelvic step using 20 healthy young male subjects, walking on a treadmill at 1-5 km/h, with normal or big steps. Step length, pelvis rotation amplitude, leg-pelvis relative phase, and the contribution of pelvis rotation to step length were calculated. When speed increased in normal walking, pelvis rotation changed from more out-of-phase to in-phase with the upper leg. Consequently, the contribution of pelvis rotation to step length was negative at lower speeds, switching to positive at 3 km/h. With big steps, leg and pelvis were more in-phase, and the contribution of pelvis rotation to step length was always positive, and relatively large. Still, the overall contribution of pelvis rotations to step length was small, less than 3%. Regression analysis revealed that leg-pelvis relative phase predicted about 60% of the variance of this contribution. The results of the present study suggest that, during normal slow walking, pelvis rotations increase, rather than decrease, the vertical movements of the centre of mass. With large steps, this does not happen, because leg and pelvis are in-phase at all speeds. Finally, it has been suggested that patients with hip flexion limitation may use larger pelvis rotations to increase step length. This, however, may only work as long as the pelvis rotates in-phase with the leg. Copyright © 2013 Elsevier B.V. All rights reserved.

Methods of operation of apparatus measuring formation resistivity from within a cased well having one measurement and two compensation steps

DOEpatents

Vail, III, William B.

1993-01-01

Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements with the apparatus at a fixed vertical depth within the cased well, the invention herein discloses methods of operation which include a measurement step and subsequent first and second compensation steps respectively resulting in improved accuracy of measurement. First and second order errors of measurement are identified, and the measurement step and two compensation steps provide methods to substantially eliminate their influence on the results. A multiple frequency apparatus adapted to movement within the well is described which simultaneously provide the measurement and two compensation steps.

Speech Privacy Problems

DTIC Science & Technology

1945-08-18

were interconnected, how? ever,, it was found that one of the oscillators had an intermit - tent, defect-. This trouble was cleared by removing the...switches> i.e., two pairsL are included in.the unit," one of ä pair of selectors {the " fast selector") steps .each time the latch operates, the other (the...34slow seleotor") steps oiice eaoh time the fast seleotor completes 25 steps. Thus, a total of 625 steps, or changes in permutation, is involved be

The two-step assemblies of basic-amino-Acid-rich Peptide with a highly charged polyoxometalate.

PubMed

Zhang, Teng; Li, Hong-Wei; Wu, Yuqing; Wang, Yizhan; Wu, Lixin

2015-06-15

Two-step assembly of a peptide from HPV16 L1 with a highly charged europium-substituted polyoxometalate (POM) cluster, accompanying a great luminescence enhancement of the inorganic polyanions, is reported. The mechanism is discussed in detail by analyzing the thermodynamic parameters from isothermal titration calorimetry (ITC), time-resolved fluorescent and NMR spectra. By comparing the actions of the peptide analogues, a binding process and model are proposed accordingly. The driving forces in each binding step are clarified, and the initial POM aggregation, basic-sequence and hydrophobic C termini of peptide are revealed to contribute essentially to the two-step assembly. The present study demonstrates both a meaningful preparation for bioinorganic materials and a strategy using POMs to modulate the assembly of peptides and even proteins, which could be extended to other proteins and/or viruses by using peptides and POMs with similar properties. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Volume Diffusion Growth Kinetics and Step Geometry in Crystal Growth

NASA Technical Reports Server (NTRS)

Mazuruk, Konstantin; Ramachandran, Narayanan

1998-01-01

The role of step geometry in two-dimensional stationary volume diff4sion process used in crystal growth kinetics models is investigated. Three different interface shapes: a) a planar interface, b) an equidistant hemispherical bumps train tAx interface, and c) a train of right angled steps, are used in this comparative study. The ratio of the super-saturation to the diffusive flux at the step position is used as a control parameter. The value of this parameter can vary as much as 50% for different geometries. An approximate analytical formula is derived for the right angled steps geometry. In addition to the kinetic models, this formula can be utilized in macrostep growth models. Finally, numerical modeling of the diffusive and convective transport for equidistant steps is conducted. In particular, the role of fluid flow resulting from the advancement of steps and its contribution to the transport of species to the steps is investigated.

Two Independent Contributions to Step Variability during Over-Ground Human Walking

PubMed Central

Collins, Steven H.; Kuo, Arthur D.

2013-01-01

Human walking exhibits small variations in both step length and step width, some of which may be related to active balance control. Lateral balance is thought to require integrative sensorimotor control through adjustment of step width rather than length, contributing to greater variability in step width. Here we propose that step length variations are largely explained by the typical human preference for step length to increase with walking speed, which itself normally exhibits some slow and spontaneous fluctuation. In contrast, step width variations should have little relation to speed if they are produced more for lateral balance. As a test, we examined hundreds of overground walking steps by healthy young adults (N = 14, age < 40 yrs.). We found that slow fluctuations in self-selected walking speed (2.3% coefficient of variation) could explain most of the variance in step length (59%, P < 0.01). The residual variability not explained by speed was small (1.5% coefficient of variation), suggesting that step length is actually quite precise if not for the slow speed fluctuations. Step width varied over faster time scales and was independent of speed fluctuations, with variance 4.3 times greater than that for step length (P < 0.01) after accounting for the speed effect. That difference was further magnified by walking with eyes closed, which appears detrimental to control of lateral balance. Humans appear to modulate fore-aft foot placement in precise accordance with slow fluctuations in walking speed, whereas the variability of lateral foot placement appears more closely related to balance. Step variability is separable in both direction and time scale into balance- and speed-related components. The separation of factors not related to balance may reveal which aspects of walking are most critical for the nervous system to control. PMID:24015308

Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag

PubMed Central

Friedrich, Melanie; Setz, Christian; Hahn, Friedrich; Matthaei, Alina; Fraedrich, Kirsten; Rauch, Pia; Henklein, Petra; Traxdorf, Maximilian; Fossen, Torgils; Schubert, Ulrich

2016-01-01

The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (l-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane. PMID:27120610

Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag.

PubMed

Friedrich, Melanie; Setz, Christian; Hahn, Friedrich; Matthaei, Alina; Fraedrich, Kirsten; Rauch, Pia; Henklein, Petra; Traxdorf, Maximilian; Fossen, Torgils; Schubert, Ulrich

2016-04-25

The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (L-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane.

Platelet-rich plasma differs according to preparation method and human variability.

PubMed

Mazzocca, Augustus D; McCarthy, Mary Beth R; Chowaniec, David M; Cote, Mark P; Romeo, Anthony A; Bradley, James P; Arciero, Robert A; Beitzel, Knut

2012-02-15

Varying concentrations of blood components in platelet-rich plasma preparations may contribute to the variable results seen in recently published clinical studies. The purposes of this investigation were (1) to quantify the level of platelets, growth factors, red blood cells, and white blood cells in so-called one-step (clinically used commercial devices) and two-step separation systems and (2) to determine the influence of three separate blood draws on the resulting components of platelet-rich plasma. Three different platelet-rich plasma (PRP) separation methods (on blood samples from eight subjects with a mean age [and standard deviation] of 31.6 ± 10.9 years) were used: two single-spin processes (PRPLP and PRPHP) and a double-spin process (PRPDS) were evaluated for concentrations of platelets, red and white blood cells, and growth factors. Additionally, the effect of three repetitive blood draws on platelet-rich plasma components was evaluated. The content and concentrations of platelets, white blood cells, and growth factors for each method of separation differed significantly. All separation techniques resulted in a significant increase in platelet concentration compared with native blood. Platelet and white blood-cell concentrations of the PRPHP procedure were significantly higher than platelet and white blood-cell concentrations produced by the so-called single-step PRPLP and the so-called two-step PRPDS procedures, although significant differences between PRPLP and PRPDS were not observed. Comparing the results of the three blood draws with regard to the reliability of platelet number and cell counts, wide variations of intra-individual numbers were observed. Single-step procedures are capable of producing sufficient amounts of platelets for clinical usage. Within the evaluated procedures, platelet numbers and numbers of white blood cells differ significantly. The intra-individual results of platelet-rich plasma separations showed wide variations in platelet and cell numbers as well as levels of growth factors regardless of separation method.

Long-term TEM analysis of the nanoleakage patterns in resin-dentin interfaces produced by different bonding strategies.

PubMed

Reis, Andre F; Giannini, Marcelo; Pereira, Patricia N R

2007-09-01

The aim of this study was to evaluate the ability of etch-and-rinse and self-etching adhesive systems to prevent time- and water-induced nanoleakage in resin-dentin interfaces over a 6-month storage period. Five commercial adhesives were tested, which comprise three different strategies of bonding resins to tooth hard tissues: one single-step self-etching adhesive (One-up Bond F (OB), Tokuyama); two two-step self-etching primers (Clearfil SE Bond (SE) and an antibacterial fluoride-containing system, Clearfil Protect Bond (CP), Kuraray Inc.); two two-step etch-and-rinse adhesives (Single Bond (SB), 3M ESPE and Prime&Bond NT (PB), Dentsply). Restored teeth were sectioned into 0.9 mm thick slabs and stored in water or mineral oil for 24 h, 3 or 6 months. A silver tracer solution was used to reveal nanometer-sized water-filled spaces and changes that occurred over time within resin-dentin interfaces. Characterization of interfaces was performed with the TEM. The two two-step self-etching primers showed little silver uptake during the 6-month experiment. Etch-and-rinse adhesives exhibited silver deposits predominantly within the hybrid layer (HL), which significantly increased for SB after water-storage. The one-step self-etching adhesive OB presented massive silver accumulation within the HL and water-trees protruding into the adhesive layer, which increased in size and quantity after water-storage. After storage in oil, reduced silver deposition was observed at the interfaces for all groups. Different levels of water-induced nanoleakage were observed for the different bonding strategies. The two-step self-etching primers, especially the antibacterial fluoride-containing system CP, showed the least nanoleakage after 6 months of storage in water.

One False Step: "Detroit," "Step" and Movies of Rising and Falling

ERIC Educational Resources Information Center

Beck, Bernard

2018-01-01

"Detroit" and "Step" are two recent movies in the context of urban riots in protest of police brutality. They refer to time periods separated by half a century, but there are common themes in the two that seem appropriate to both times. The movies are not primarily concerned with the riot events, but the riot is a major…

Study of the highly ordered TiO2 nanotubes physical properties prepared with two-step anodization

NASA Astrophysics Data System (ADS)

Pishkar, Negin; Ghoranneviss, Mahmood; Ghorannevis, Zohreh; Akbari, Hossein

2018-06-01

Highly ordered hexagonal closely packed titanium dioxide nanotubes (TiO2 NTs) were successfully grown by a two-step anodization process. The TiO2 NTs were synthesized by electrochemical anodization of titanium foils in an ethylene glycol based electrolyte solution containing 0.3 wt% NH4F and 2 vol% deionized (DI) water at constant potential (50 V) for 1 h at room temperature. Physical properties of the TiO2 NTs, which were prepared via one and two-step anodization, were investigated. Atomic Force Microscopy (AFM) analysis revealed that anodization and subsequently peeled off the TiO2 NTs caused to the periodic pattern on the Ti surface. In order To study the nanotubes morphology, Field Emission Scanning Electron Microscopy (FESEM) was used, which was revealed that the two-step anodization resulted highly ordered hexagonal TiO2 NTs. Crystal structures of the TiO2 NTs were mainly anatase, determined by X-ray diffraction analysis. Optical studies were performed by Diffuse Reflection Spectra (DRS) and Photoluminescence (PL) analysis showed that the band gap of TiO2 NTs prepared via two-step anodization was lower than the band gap of samples prepared by one-step anodization process.

A “Train-Track” Technique in Anatomic Reconstruction of SVC Bifurcation Complicated by Cardiac Tamponade: An Introspection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karuppasamy, Karunakaravel, E-mail: karuppk@ccf.org; Al-Natour, Mohammed, E-mail: mnatour85@msn.com; Gurajala, Ram Kishore, E-mail: gurajar@ccf.org

This report describes a stenting technique used to anatomically reconstruct superior vena cava (SVC) bifurcation in a patient with benign SVC syndrome. After recanalizing the SVC bifurcation, we exchanged two 0.035-in. wires for two 0.018-in. wires, deployed the SVC stent over these two wires (“train-track” technique), and stented each innominate vein over one wire. However, our decisions to recanalize both innominate veins, use the “buddy-wire” technique for SVC dilation, and dilate the SVC to 16 mm before stent deployment likely contributed to SVC tear, which was managed by resuscitation, SVC stent placement, and pericardial drainage. Here, we describe the steps ofmore » the train-track technique, which can be adopted to reconstruct other bifurcations; we also discuss the controversial aspects of this case.« less

One-pot and two-step synthesis of novel carbonylthioureas and dicarbonyldithioureas derivatives

NASA Astrophysics Data System (ADS)

Banaei, Alireza; Shiran, Jafar Abbasi; Saadat, Afshin; Ardabili, Farnaz Fazlalizadeh; McArdle, Patrick

2015-11-01

One-pot, two-step synthesis of several 1-cyclopropanecarbonyl-3-(substituted phenyl)-thioureas and 1-(phenylene-1,4-dione)-3,3‧-(substituted phenyl)-dithioureas have been successfully prepared. The structures of the synthesized compounds were confirmed by elemental analysis, FT-IR spectroscopy and NMR. Also the crystal structure one of these compounds was determined by X-ray crystallography. All synthesized compounds were evaluated for antibacterial activity using Salmonella enterica (SE), Micrococcus luteus (ML), Bacillus subtilis (BS) and Pseudomonas aeruginosa (PS).

A two-step non-flowcytometry-based naïve B cell isolation method and its application in Staphylococcal enterotoxin B (SEB) presentation.

PubMed

Chokeshai-u-saha, Kaj; Buranapraditkun, Supranee; Jacquet, Alain; Nguyen, Catherine; Ruxrungtham, Kiat

2012-09-01

To study the role of human naïve B cells in antigen presentation and stimulation to naïve CD4+ T cell, a suitable method to reproducibly isolate sufficient naïve B cells is required. To improve the purity of isolated naive B cells obtained from a conventional one-step magnetic bead method, we added a rosetting step to enrich total B cell isolates from human whole blood samples prior to negative cell sorting by magnetic beads. The acquired naïve B cells were analyzed for phenotypes and for their role in Staphylococcal enterotoxin B (SEB) presentation to naïve CD4+ T cells. The mean (SD) naïve B cell (CD19+/CD27-) purity obtained from this two-step method compared with the one-step method was 97% (1.0) versus 90% (1.2), respectively. This two-step method can be used with a sample of whole blood as small as 10 ml. The isolated naive B cells were phenotypically at a resting state and were able to prime naïve CD4+ T cell activation by Staphylococcal enterotoxin B (SEB) presentation. This two-step non-flow cytometry-based approach improved the purity of isolated naïve B cells compared with conventional one-step magnetic bead method. It also worked well with a small blood volume. In addition, this study showed that the isolated naïve B cells can present a super-antigen "SEB" to activate naïve CD4 cells. These methods may thus be useful for further in vitro characterization of human naïve B cells and their roles as antigen presenting cells in various diseases.

Evaluation of one-step luminescent cyanoacrylate fuming.

PubMed

Khuu, Alicia; Chadwick, Scott; Spindler, Xanthe; Lam, Rolanda; Moret, Sébastien; Roux, Claude

2016-06-01

One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster+Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster+Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster+Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Modeling Woven Polymer Matrix Composites with MAC/GMC

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Arnold, Steven M. (Technical Monitor)

2000-01-01

NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) is used to predict the elastic properties of plain weave polymer matrix composites (PMCs). The traditional one step three-dimensional homogertization procedure that has been used in conjunction with MAC/GMC for modeling woven composites in the past is inaccurate due to the lack of shear coupling inherent to the model. However, by performing a two step homogenization procedure in which the woven composite repeating unit cell is homogenized independently in the through-thickness direction prior to homogenization in the plane of the weave, MAC/GMC can now accurately model woven PMCs. This two step procedure is outlined and implemented, and predictions are compared with results from the traditional one step approach and other models and experiments from the literature. Full coupling of this two step technique with MAC/ GMC will result in a widely applicable, efficient, and accurate tool for the design and analysis of woven composite materials and structures.

Steps for Washroom and Locker Room Sustainability.

ERIC Educational Resources Information Center

Wiens, Janet

2003-01-01

Administrators and design teams can use proven approaches to create sustainable washrooms and locker rooms. Presents design strategies related to lighting, flooring, and water conservation that contribute to sustainability, then describes one college's experiences developing sustainable architecture, explaining how the building takes full…

A randomized controlled clinical trial of a HEMA-free all-in-one adhesive in non-carious cervical lesions at 1 year.

PubMed

Van Landuyt, K L; Peumans, M; Fieuws, S; De Munck, J; Cardoso, M V; Ermis, R B; Lambrechts, P; Van Meerbeek, B

2008-10-01

One-step self-etch adhesives are the most recent generation of adhesives introduced onto the market. The objective of this randomized controlled clinical trial was to test the hypothesis that a one-step self-etch adhesive performs equally well as a conventional three-step etch&rinse adhesive (gold standard). Fifty-two patients had 267 non-carious cervical lesions restored with Gradia Direct Anterior (GC). These composite restorations were bonded either with the 'all-in-one' adhesive G-Bond (GC) or with the three-step etch&rinse adhesive Optibond FL (Kerr). The restorations were evaluated after 6 and 12 months clinical service regarding their retention, marginal integrity and discoloration, caries occurrence, preservation of tooth vitality and post-operative sensitivity. Retention loss, severe marginal defects and/or discoloration that needed intervention (repair or replacement) and the occurrence of caries were considered as clinical failures. A logistic regression analysis with generalized estimating equations was used to account for the clustered data (multiple restorations per patient). The recall rate at 1 year was 98%. The statistical analysis revealed a relatively low patient factor, indicating that supplementary information could be obtained from the additional restorations placed per patient. The retention rate for G-Bond was 98.5% compared to 99.3% for Optibond FL, due to the retention loss of two and one restorations, respectively. There were no significant differences between the two adhesives regarding the evaluated parameters except for the presence of small enamel marginal defects with G-Bond. After 12 months, the simplified one-step G-Bond and the three-step Optibond FL were clinically equally successful, even though both adhesives were characterized by progressive degradation of marginal adaptation, and G-Bond exhibited more small enamel marginal defects.

a Two-Step Classification Approach to Distinguishing Similar Objects in Mobile LIDAR Point Clouds

NASA Astrophysics Data System (ADS)

He, H.; Khoshelham, K.; Fraser, C.

2017-09-01

Nowadays, lidar is widely used in cultural heritage documentation, urban modeling, and driverless car technology for its fast and accurate 3D scanning ability. However, full exploitation of the potential of point cloud data for efficient and automatic object recognition remains elusive. Recently, feature-based methods have become very popular in object recognition on account of their good performance in capturing object details. Compared with global features describing the whole shape of the object, local features recording the fractional details are more discriminative and are applicable for object classes with considerable similarity. In this paper, we propose a two-step classification approach based on point feature histograms and the bag-of-features method for automatic recognition of similar objects in mobile lidar point clouds. Lamp post, street light and traffic sign are grouped as one category in the first-step classification for their inter similarity compared with tree and vehicle. A finer classification of the lamp post, street light and traffic sign based on the result of the first-step classification is implemented in the second step. The proposed two-step classification approach is shown to yield a considerable improvement over the conventional one-step classification approach.

Two-loop beam and soft functions for rapidity-dependent jet vetoes

NASA Astrophysics Data System (ADS)

Gangal, Shireen; Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J.

2017-02-01

Jet vetoes play an important role in many analyses at the LHC. Traditionally, jet vetoes have been imposed using a restriction on the transverse momentum p Tj of jets. Alternatively, one can also consider jet observables for which p Tj is weighted by a smooth function of the jet rapidity y j that vanishes as | y j | → ∞. Such observables are useful as they provide a natural way to impose a tight veto on central jets but a looser one at forward rapidities. We consider two such rapidity-dependent jet veto observables, T_{Bj} and {T_{Cj} , and compute the required beam and dijet soft functions for the jet-vetoed color-singlet production cross section at two loops. At this order, clustering effects from the jet algorithm become important. The dominant contributions are computed fully analytically while corrections that are subleading in the limit of small jet radii are expressed in terms of finite numerical integrals. Our results enable the full NNLL' resummation and are an important step towards N3LL resummation for cross sections with a T_{Bj} or T_{Cj} jet veto.

Tetraethylene glycol promoted two-step, one-pot rapid synthesis of indole-3-[1- 11C]acetic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sojeong; Qu, Wenchao; Alexoff, David L.

2014-12-12

An operationally friendly, two-step, one-pot process has been developed for the rapid synthesis of carbon-11 labeled indole-3-acetic acid ([ 11]IAA or [ 11]auxin). By replacing an aprotic polar solvent with tetraethylene glycol, nucleophilic [ 11]cyanation and alkaline hydrolysis reactions were performed consecutively in a single pot without a time-consuming intermediate purification step. The entire production time for this updated procedure is 55 min, which dramatically simplifies the entire synthesis and reduces the starting radioactivity required for a whole plant imaging study.

Prediction of child performance on a parent-child behavioral approach test with animal phobic children.

PubMed

Ollendick, Thomas H; Lewis, Krystal M; Cowart, Maria J W; Davis, Thompson

2012-07-01

A host of factors including genetic influences, temperament characteristics, learning experiences, information processing biases, parental psychopathology, and specific parenting practices have been hypothesized to contribute to the development and expression of children's phobias. In the present study, the authors focused on parental psychopathology (phobic anxiety) and parenting behaviors (warmth, involvement) in the prediction of child performance on a behavioral approach test (BAT). All children (n = 44) experienced a phobia of animals and were clinic referred. The youth completed two BATs: the first alone and the second one with a parent present. Overall, performance was greater on the parent-present BAT (58% of steps completed) than on the child-alone BAT (38% of steps completed), although considerable variability was present. Performance on the parent-present BAT was associated with parental warmth and involvement but not parental phobic anxiety. Implications of these findings were discussed, and their implications for the use of behavioral analogues tests were explored.

Effects of two-step homogenization on precipitation behavior of Al{sub 3}Zr dispersoids and recrystallization resistance in 7150 aluminum alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Zhanying; Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110819, China,; Zhao, Gang

2015-04-15

The effect of two-step homogenization treatments on the precipitation behavior of Al{sub 3}Zr dispersoids was investigated by transmission electron microscopy (TEM) in 7150 alloys. Two-step treatments with the first step in the temperature range of 300–400 °C followed by the second step at 470 °C were applied during homogenization. Compared with the conventional one-step homogenization, both a finer particle size and a higher number density of Al{sub 3}Zr dispersoids were obtained with two-step homogenization treatments. The most effective dispersoid distribution was attained using the first step held at 300 °C. In addition, the two-step homogenization minimized the precipitate free zonesmore » and greatly increased the number density of dispersoids near dendrite grain boundaries. The effect of two-step homogenization on recrystallization resistance of 7150 alloys with different Zr contents was quantitatively analyzed using the electron backscattered diffraction (EBSD) technique. It was found that the improved dispersoid distribution through the two-step treatment can effectively inhibit the recrystallization process during the post-deformation annealing for 7150 alloys containing 0.04–0.09 wt.% Zr, resulting in a remarkable reduction of the volume fraction and grain size of recrystallization grains. - Highlights: • Effect of two-step homogenization on Al{sub 3}Zr dispersoids was investigated by TEM. • Finer and higher number of dispersoids obtained with two-step homogenization • Minimized the precipitate free zones and improved the dispersoid distribution • Recrystallization resistance with varying Zr content was quantified by EBSD. • Effectively inhibit the recrystallization through two-step treatments in 7150 alloy.« less

A Conformational Transition in the Myosin VI Converter Contributes to the Variable Step Size

PubMed Central

Ovchinnikov, V.; Cecchini, M.; Vanden-Eijnden, E.; Karplus, M.

2011-01-01

Myosin VI (MVI) is a dimeric molecular motor that translocates backwards on actin filaments with a surprisingly large and variable step size, given its short lever arm. A recent x-ray structure of MVI indicates that the large step size can be explained in part by a novel conformation of the converter subdomain in the prepowerstroke state, in which a 53-residue insert, unique to MVI, reorients the lever arm nearly parallel to the actin filament. To determine whether the existence of the novel converter conformation could contribute to the step-size variability, we used a path-based free-energy simulation tool, the string method, to show that there is a small free-energy difference between the novel converter conformation and the conventional conformation found in other myosins. This result suggests that MVI can bind to actin with the converter in either conformation. Models of MVI/MV chimeric dimers show that the variability in the tilting angle of the lever arm that results from the two converter conformations can lead to step-size variations of ∼12 nm. These variations, in combination with other proposed mechanisms, could explain the experimentally determined step-size variability of ∼25 nm for wild-type MVI. Mutations to test the findings by experiment are suggested. PMID:22098742

15 CFR 752.5 - Steps you must follow to apply for an SCL.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Steps you must follow to apply for an... COMPREHENSIVE LICENSE § 752.5 Steps you must follow to apply for an SCL. (a) Step One: Establish applicant...; and (iv) Evidence of all parties knowledge of all provisions of the EAR. (b) Step Two: Establish...

Two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy.

PubMed

Liu, Yu; Li, Ji-Jia; Zu, Peng; Liu, Hong-Xu; Yu, Zhan-Wu; Ren, Yi

2017-12-07

To introduce a two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy and assess its clinical application. One hundred and twenty-two patients with middle or lower esophageal cancer who underwent laparoscopic-thoracoscopic Ivor-Lewis esophagectomy at Liaoning Cancer Hospital and Institute from March 2014 to March 2016 were included in this study, and divided into two groups based on the procedure used for creating a gastric tube. One group used a two-step method for creating a gastric tube, and the other group used the conventional method. The two groups were compared regarding the operating time, surgical complications, and number of stapler cartridges used. The mean operating time was significantly shorter in the two-step method group than in the conventional method group [238 (179-293) min vs 272 (189-347) min, P < 0.01]. No postoperative death occurred in either group. There was no significant difference in the rate of complications [14 (21.9%) vs 13 (22.4%), P = 0.55] or mean number of stapler cartridges used [5 (4-6) vs 5.2 (5-6), P = 0.007] between the two groups. The two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy has the advantages of simple operation, minimal damage to the tubular stomach, and reduced use of stapler cartridges.

Optimal Padding for the Two-Dimensional Fast Fourier Transform

NASA Technical Reports Server (NTRS)

Dean, Bruce H.; Aronstein, David L.; Smith, Jeffrey S.

2011-01-01

One-dimensional Fast Fourier Transform (FFT) operations work fastest on grids whose size is divisible by a power of two. Because of this, padding grids (that are not already sized to a power of two) so that their size is the next highest power of two can speed up operations. While this works well for one-dimensional grids, it does not work well for two-dimensional grids. For a two-dimensional grid, there are certain pad sizes that work better than others. Therefore, the need exists to generalize a strategy for determining optimal pad sizes. There are three steps in the FFT algorithm. The first is to perform a one-dimensional transform on each row in the grid. The second step is to transpose the resulting matrix. The third step is to perform a one-dimensional transform on each row in the resulting grid. Steps one and three both benefit from padding the row to the next highest power of two, but the second step needs a novel approach. An algorithm was developed that struck a balance between optimizing the grid pad size with prime factors that are small (which are optimal for one-dimensional operations), and with prime factors that are large (which are optimal for two-dimensional operations). This algorithm optimizes based on average run times, and is not fine-tuned for any specific application. It increases the amount of times that processor-requested data is found in the set-associative processor cache. Cache retrievals are 4-10 times faster than conventional memory retrievals. The tested implementation of the algorithm resulted in faster execution times on all platforms tested, but with varying sized grids. This is because various computer architectures process commands differently. The test grid was 512 512. Using a 540 540 grid on a Pentium V processor, the code ran 30 percent faster. On a PowerPC, a 256x256 grid worked best. A Core2Duo computer preferred either a 1040x1040 (15 percent faster) or a 1008x1008 (30 percent faster) grid. There are many industries that can benefit from this algorithm, including optics, image-processing, signal-processing, and engineering applications.

A New Two-Step Approach for Hands-On Teaching of Gene Technology: Effects on Students' Activities during Experimentation in an Outreach Gene Technology Lab

ERIC Educational Resources Information Center

Scharfenberg, Franz-Josef; Bogner, Franz X.

2011-01-01

Emphasis on improving higher level biology education continues. A new two-step approach to the experimental phases within an outreach gene technology lab, derived from cognitive load theory, is presented. We compared our approach using a quasi-experimental design with the conventional one-step mode. The difference consisted of additional focused…

How Different kinds of Communication and the Mass Media Affect Tourism.

DTIC Science & Technology

1984-12-01

C. Criticism of the Two-Step Flow Model------------------------------ 38 3. The Multi-Step Flow Model or Theory------- 39 4. One-Step Flow Model or... Criticism of the Two-Step Flow Model Researchers have identified deficiencies in the r,,c-w:er :low-model. McNelly, for instance, se,7s mass...evidence of the relative importance of cc munication on the diffusion flow. 38 Rogers ’as criticized ] the theor-y on the grounds that: neither its

Design and fabrication of realistic adhesively bonded joints

NASA Technical Reports Server (NTRS)

Shyprykevich, P.

1983-01-01

Eighteen bonded joint test specimens representing three different designs of a composite wing chordwise bonded splice were designed and fabricated using current aircraft industry practices. Three types of joints (full wing laminate penetration, two side stepped; midthickness penetration, one side stepped; and partial penetration, scarfed) were analyzed using state of the art elastic joint analysis modified for plastic behavior of the adhesive. The static tensile fail load at room temperature was predicted to be: (1) 1026 kN/m (5860 1b/in) for the two side stepped joint; (2) 925 kN/m (5287 1b/in) for the one side stepped joint; and (3) 1330 kN/m (7600 1b/in) for the scarfed joint. All joints were designed to fail in the adhesive.

Magnetoresistance measurement of permalloy thin film rings with triangular fins

NASA Astrophysics Data System (ADS)

Lai, Mei-Feng; Hsu, Chia-Jung; Liao, Chun-Neng; Chen, Ying-Jiun; Wei, Zung-Hang

2010-01-01

Magnetization reversals in permalloy rings controlled by nucleation sites using triangular fins at the same side and diagonal with respect to the field direction are demonstrated by magnetoresistance measurement and micromagnetic simulation. In the ring with triangular fins at the same side, there exists two-step reversal from onion to flux-closure state (or vortex state) and then from flux-closure (or vortex state) to reverse onion state; in the ring with diagonal triangular fins, one-step reversal occurs directly from onion to reverse onion state. The reversal processes are repeatable and controllable in contrast to an ideal ring without triangular fins where one-step and two-step reversals occur randomly in sweep-up and sweep-down processes.

A new methodology to determine kinetic parameters for one- and two-step chemical models

NASA Technical Reports Server (NTRS)

Mantel, T.; Egolfopoulos, F. N.; Bowman, C. T.

1996-01-01

In this paper, a new methodology to determine kinetic parameters for simple chemical models and simple transport properties classically used in DNS of premixed combustion is presented. First, a one-dimensional code is utilized to performed steady unstrained laminar methane-air flame in order to verify intrinsic features of laminar flames such as burning velocity and temperature and concentration profiles. Second, the flame response to steady and unsteady strain in the opposed jet configuration is numerically investigated. It appears that for a well determined set of parameters, one- and two-step mechanisms reproduce the extinction limit of a laminar flame submitted to a steady strain. Computations with the GRI-mech mechanism (177 reactions, 39 species) and multicomponent transport properties are used to validate these simplified models. A sensitivity analysis of the preferential diffusion of heat and reactants when the Lewis number is close to unity indicates that the response of the flame to an oscillating strain is very sensitive to this number. As an application of this methodology, the interaction between a two-dimensional vortex pair and a premixed laminar flame is performed by Direct Numerical Simulation (DNS) using the one- and two-step mechanisms. Comparison with the experimental results of Samaniego et al. (1994) shows a significant improvement in the description of the interaction when the two-step model is used.

Detection of canine distemper virus (CDV) through one step RT-PCR combined with nested PCR.

PubMed

Kim, Y H; Cho, K W; Youn, H Y; Yoo, H S; Han, H R

2001-04-01

A one step reverse transcription PCR (RT-PCR) combined nested PCR was set up to increase efficiency in the diagnosis of canine distemper virus (CDV) infection after developement of nested PCR. Two PCR primer sets were designed based on the sequence of nucleocapsid gene of CDV Onderstepoort strain. One-step RT-PCR with the outer primer pair was revealed to detect 10(2) PFU/ml. The sensitivity was increased hundredfold using the one-step RT-PCR combined with the nested PCR. Specificity of the PCR was also confirmed using other related canine virus and peripheral blood mononuclear cells (PBMC) and body secretes of healthy dogs. Of the 51 blood samples from dogs clinically suspected of CD, 45 samples were revealed as positive by one-step RT-PCR combined with nested PCR. However, only 15 samples were identified as positive with a single one step RT-PCR. Therefore approximately 60% increase in the efficiency of the diagnosis was observed by the combined method. These results suggested that one step RT-PCR combined with nested PCR could be a sensitive, specific, and practical method for diagnosis of CDV infection.

Analyzing the dependence of oxygen incorporation current density on overpotential and oxygen partial pressure in mixed conducting oxide electrodes.

PubMed

Guan, Zixuan; Chen, Di; Chueh, William C

2017-08-30

The oxygen incorporation reaction, which involves the transformation of an oxygen gas molecule to two lattice oxygen ions in a mixed ionic and electronic conducting solid, is a ubiquitous and fundamental reaction in solid-state electrochemistry. To understand the reaction pathway and to identify the rate-determining step, near-equilibrium measurements have been employed to quantify the exchange coefficients as a function of oxygen partial pressure and temperature. However, because the exchange coefficient contains contributions from both forward and reverse reaction rate constants and depends on both oxygen partial pressure and oxygen fugacity in the solid, unique and definitive mechanistic assessment has been challenging. In this work, we derive a current density equation as a function of both oxygen partial pressure and overpotential, and consider both near and far from equilibrium limits. Rather than considering specific reaction pathways, we generalize the multi-step oxygen incorporation reaction into the rate-determining step, preceding and following quasi-equilibrium steps, and consider the number of oxygen ions and electrons involved in each. By evaluating the dependence of current density on oxygen partial pressure and overpotential separately, one obtains the reaction orders for oxygen gas molecules and for solid-state species in the electrode. We simulated the oxygen incorporation current density-overpotential curves for praseodymium-doped ceria for various candidate rate-determining steps. This work highlights a promising method for studying the exchange kinetics far away from equilibrium.

Two-step impression/ injection, an alternative putty/ wash impression technique: case report.

PubMed

Caputi, S; Murmura, G; Sinjari, B; Varvara, G

2012-01-01

We here describe a new technique for making a definitive impression that we refer to as the two-step impression/injection technique. This technique initially follows the classical one-step putty/ light-body impression technique with the polymerization of the putty and the light-body compound. This is then followed by the second step: injection of extra-light-body compound into the preparation through a hole in the metal stock tray. The aim of this additional step is to control the wash bulk and minimize the changes that can produce unfavorable impression results. This new two-step impression/injection technique allows displacement of soft tissues, such as the tongue, during the first seating of the putty and wash materials, while in the second step, the extra-light-body compound records all of the finer details without being compressed.

Acoustic investigation of wall jet over a backward-facing step using a microphone phased array

NASA Astrophysics Data System (ADS)

Perschke, Raimund F.; Ramachandran, Rakesh C.; Raman, Ganesh

2015-02-01

The acoustic properties of a wall jet over a hard-walled backward-facing step of aspect ratios 6, 3, 2, and 1.5 are studied using a 24-channel microphone phased array at Mach numbers up to M=0.6. The Reynolds number based on inflow velocity and step height assumes values from Reh = 3.0 ×104 to 7.2 ×105. Flow without and with side walls is considered. The experimental setup is open in the wall-normal direction and the expansion ratio is effectively 1. In case of flow through a duct, symmetry of the flow in the spanwise direction is lost downstream of separation at all but the largest aspect ratio as revealed by oil paint flow visualization. Hydrodynamic scattering of turbulence from the trailing edge of the step contributes significantly to the radiated sound. Reflection of acoustic waves from the bottom plate results in a modulation of power spectral densities. Acoustic source localization has been conducted using a 24-channel microphone phased array. Convective mean-flow effects on the apparent source origin have been assessed by placing a loudspeaker underneath a perforated flat plate and evaluating the displacement of the beamforming peak with inflow Mach number. Two source mechanisms are found near the step. One is due to interaction of the turbulent wall jet with the convex edge of the step. Free-stream turbulence sound is found to be peaked downstream of the step. Presence of the side walls increases free-stream sound. Results of the flow visualization are correlated with acoustic source maps. Trailing-edge sound and free-stream turbulence sound can be discriminated using source localization.

Permeability of Dental Adhesives – A SEM Assessment

PubMed Central

Malacarne-Zanon, Juliana; de Andrade e Silva, Safira M.; Wang, Linda; de Goes, Mario F.; Martins, Adriano Luis; Narvaes-Romani, Eliene O.; Anido-Anido, Andrea; Carrilho, Marcela R. O.

2010-01-01

Objectives: To morphologically evaluate the permeability of different commercial dental adhesives using scanning electron microscopy. Methods: Seven adhesive systems were evaluated: one three-step system (Scotchbond Multi-Purpose - MP); one two-step self-etching primer system (Clearfil SE Bond – SE); three two-step etch-and-rinse systems (Single Bond 2 – SB; Excite – EX; One-Step – OS); and two single-step self-etching adhesives (Adper Prompt – AP; One-Up Bond F – OU). The mixture of primer and bond agents of the Clearfil SE Bond system (SE-PB) was also tested. The adhesives were poured into a brass mold (5.8 mm x 0.8 mm) and light-cured for 80 s at 650 mW/cm2. After a 24 h desiccation process, the specimens were immersed in a 50% ammoniac silver nitrate solution for tracer permeation. Afterwards, they were sectioned in ultra-fine slices, carbon-coated, and analyzed under backscattered electrons in a scanning electron microscopy. Results: MP and SE showed slight and superficial tracer permeation. In EX, SB, and OS, permeation extended beyond the inner superficies of the specimens. SE-PB did not mix well, and most of the tracer was precipitated into the primer agent. In AP and OU, “water-trees” were observed all over the specimens. Conclusions: Different materials showed distinct permeability in aqueous solution. The extent of tracer permeation varied according to the composition of each material and it was more evident in the more hydrophilic and solvated ones. PMID:20922163

Source apportionment and heavy metal health risk (HMHR) quantification from sources in a southern city in China, using an ME2-HMHR model.

PubMed

Peng, Xing; Shi, GuoLiang; Liu, GuiRong; Xu, Jiao; Tian, YingZe; Zhang, YuFen; Feng, YinChang; Russell, Armistead G

2017-02-01

Heavy metals (Cr, Co, Ni, As, Cd, and Pb) can be bound to PM adversely affecting human health. Quantifying the source impacts on heavy metals can provide source-specific estimates of the heavy metal health risk (HMHR) to guide effective development of strategies to reduce such risks from exposure to heavy metals in PM 2.5 (particulate matter (PM) with aerodynamic diameter less than or equal to 2.5 μm). In this study, a method combining Multilinear Engine 2 (ME2) and a risk assessment model is developed to more effectively quantify source contributions to HMHR, including heavy metal non-cancer risk (non-HMCR) and cancer risk (HMCR). The combined model (called ME2-HMHR) has two steps: step1, source contributions to heavy metals are estimated by employing the ME2 model; step2, the source contributions in step 1 are introduced into the risk assessment model to calculate the source contributions to HMHR. The approach was applied to Huzou, China and five significant sources were identified. Soil dust is the largest source of non-HMCR. For HMCR, the source contributions of soil dust, coal combustion, cement dust, vehicle, and secondary sources are 1.0 × 10 -4 , 3.7 × 10 -5 , 2.7 × 10 -6 , 1.6 × 10 -6 and 1.9 × 10 -9 , respectively. The soil dust is the largest contributor to HMCR, being driven by the high impact of soil dust on PM 2.5 and the abundance of heavy metals in soil dust. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a modularized two-step (M2S) chromosome integration technique for integration of multiple transcription units in Saccharomyces cerevisiae.

PubMed

Li, Siwei; Ding, Wentao; Zhang, Xueli; Jiang, Huifeng; Bi, Changhao

2016-01-01

Saccharomyces cerevisiae has already been used for heterologous production of fuel chemicals and valuable natural products. The establishment of complicated heterologous biosynthetic pathways in S. cerevisiae became the research focus of Synthetic Biology and Metabolic Engineering. Thus, simple and efficient genomic integration techniques of large number of transcription units are demanded urgently. An efficient DNA assembly and chromosomal integration method was created by combining homologous recombination (HR) in S. cerevisiae and Golden Gate DNA assembly method, designated as modularized two-step (M2S) technique. Two major assembly steps are performed consecutively to integrate multiple transcription units simultaneously. In Step 1, Modularized scaffold containing a head-to-head promoter module and a pair of terminators was assembled with two genes. Thus, two transcription units were assembled with Golden Gate method into one scaffold in one reaction. In Step 2, the two transcription units were mixed with modules of selective markers and integration sites and transformed into S. cerevisiae for assembly and integration. In both steps, universal primers were designed for identification of correct clones. Establishment of a functional β-carotene biosynthetic pathway in S. cerevisiae within 5 days demonstrated high efficiency of this method, and a 10-transcriptional-unit pathway integration illustrated the capacity of this method. Modular design of transcription units and integration elements simplified assembly and integration procedure, and eliminated frequent designing and synthesis of DNA fragments in previous methods. Also, by assembling most parts in Step 1 in vitro, the number of DNA cassettes for homologous integration in Step 2 was significantly reduced. Thus, high assembly efficiency, high integration capacity, and low error rate were achieved.

Optimizing the identification of patients with axial spondyloarthritis in primary care--the case for a two-step strategy combining the most relevant clinical items with HLA B27.

PubMed

Braun, Annalina; Gnann, Holger; Saracbasi, Ertan; Grifka, Joachim; Kiltz, Uta; Letschert, Katrin; Braun, Jürgen

2013-08-01

The combination of clinical items suggestive of inflammatory back pain has proved useful for early identification of patients with axial SpA (axSpA) in primary care. However, whether HLA B27 contributes to that is unclear, and published recommendations have advised against it. In this study, we reanalysed data of that trial in relation to the HLA B27 results. Consecutive patients <45 years old (n = 950) with back pain (BP) >2 months presenting to 143 orthopaedists were referred to 36 rheumatologists who made the diagnosis. The predictive value of HLA B27 (n = 298) alone and in combination, including modelling and a two-step strategy, was calculated. Among all patients (mean age 36 years, 52% female, median duration of BP 32 months), 107 had axSpA (36%). Using a simple model, HLA B27 alone performed better than all combinations of clinical items and adding it did not improve likelihood ratios (LRs). Using modelling, two-phase strategies were analysed. Additional items were only relevant in the HLA B27-negative group: improvement by movement, buttock pain and psoriasis. Combining this information revealed the presumably best strategy to predict axSpA in primary care: more than one of these items or HLA B27 need to be present (sensitivity 80.4%, specificity 75.4%, LR+ 3.27 and LR- 0.26). This is the first study to show that patients with axSpA are more reliably identified in primary care by a strategy that includes HLA B27. Because of the two-step approach, the test needs to be performed in only about half of patients with chronic BP.

Intrinsically water-repellent copper oxide surfaces; An electro-crystallization approach

NASA Astrophysics Data System (ADS)

Akbari, Raziyeh; Ramos Chagas, Gabriela; Godeau, Guilhem; Mohammadizadeh, Mohammadreza; Guittard, Frédéric; Darmanin, Thierry

2018-06-01

Use of metal oxide thin layers is increased due to their good durability under environmental conditions. In this work, the repeatable nanostructured crystalite Cu2O thin films, developed by electrodeposition method without any physical and chemical modifications, demonstrate good hydrophobicity. Copper (I) oxide (Cu2O) layers were fabricated on gold/Si(1 0 0) substrates by different electrodeposition methods i.e. galvanostatic deposition, cyclic voltammetry, and pulse potentiostatic deposition and using copper sulfate (in various concentrations) as a precursor. The greatest crystalline face on prepared Cu2O samples is (1 1 1) which is the most hydrophobic facet of Cu2O cubic structure. Indeed, different crystallite structures such as nanotriangles and truncated octahedrons were formed on the surface for various electrodeposition methods. The increase of the contact angle (θw) measured by the rest time, reaching to about 135°, was seen at different rates and electrodeposition methods. In addition, two-step deposition surfaces were also prepared by applying two of the mentioned methods, alternatively. In general, the morphology of the two-step deposition surfaces showed some changes compared to that of one-step samples, allowing the formation of different crystallite shapes. Moreover, the wettability behavior showd the larger θw of the two-step deposition layers compared to the related one-step deposition layers. Therefore, the highest observed θw was related to the one of two-step deposition layers due to the creation of small octahedral structures on the surface, having narrow and deep valleys. However, there was an exception which was due to the resulted big structures and broad valleys on the surface. So, it is possible to engineer different crystallites shapes using the proposed two-step deposition method. It is expected that hydrophobic crystallite thin films can be used in environmental and electronic applications to save energy and materials properties.

One-pot, two-step synthesis of imidazo[1,2-a]benzimidazoles via a multicomponent [4 + 1] cycloaddition reaction.

PubMed

Hsiao, Ya-Shan; Narhe, Bharat D; Chang, Ying-Sheng; Sun, Chung-Ming

2013-10-14

A one-pot, two-step synthesis of imidazo[1,2-a]benzimidazoles has been achieved by a three-component reaction of 2-aminobenzimidazoles with an aromatic aldehyde and an isocyanide. The reaction involving condensation of 2-aminobenzimidazole with an aldehyde is run under microwave activation to generate an imine intermediate under basic conditions which then undergoes [4 + 1] cycloaddition with an isocyanide.

Parsing the roles of neck-linker docking and tethered head diffusion in the stepping dynamics of kinesin.

PubMed

Zhang, Zhechun; Goldtzvik, Yonathan; Thirumalai, D

2017-11-14

Kinesin walks processively on microtubules (MTs) in an asymmetric hand-over-hand manner consuming one ATP molecule per 16-nm step. The individual contributions due to docking of the approximately 13-residue neck linker to the leading head (deemed to be the power stroke) and diffusion of the trailing head (TH) that contributes in propelling the motor by 16 nm have not been quantified. We use molecular simulations by creating a coarse-grained model of the MT-kinesin complex, which reproduces the measured stall force as well as the force required to dislodge the motor head from the MT, to show that nearly three-quarters of the step occurs by bidirectional stochastic motion of the TH. However, docking of the neck linker to the leading head constrains the extent of diffusion and minimizes the probability that kinesin takes side steps, implying that both the events are necessary in the motility of kinesin and for the maintenance of processivity. Surprisingly, we find that during a single step, the TH stochastically hops multiple times between the geometrically accessible neighboring sites on the MT before forming a stable interaction with the target binding site with correct orientation between the motor head and the [Formula: see text] tubulin dimer.

Improved Reproducibility for Perovskite Solar Cells with 1 cm2 Active Area by a Modified Two-Step Process.

PubMed

Shen, Heping; Wu, Yiliang; Peng, Jun; Duong, The; Fu, Xiao; Barugkin, Chog; White, Thomas P; Weber, Klaus; Catchpole, Kylie R

2017-02-22

With rapid progress in recent years, organohalide perovskite solar cells (PSC) are promising candidates for a new generation of highly efficient thin-film photovoltaic technologies, for which up-scaling is an essential step toward commercialization. In this work, we propose a modified two-step method to deposit the CH 3 NH 3 PbI 3 (MAPbI 3 ) perovskite film that improves the uniformity, photovoltaic performance, and repeatability of large-area perovskite solar cells. This method is based on the commonly used two-step method, with one additional process involving treating the perovskite film with concentrated methylammonium iodide (MAI) solution. This additional treatment is proved to be helpful for tailoring the residual PbI 2 level to an optimal range that is favorable for both optical absorption and inhibition of recombination. Scanning electron microscopy and photoluminescence image analysis further reveal that, compared to the standard two-step and one-step methods, this method is very robust for achieving uniform and pinhole-free large-area films. This is validated by the photovoltaic performance of the prototype devices with an active area of 1 cm 2 , where we achieved the champion efficiency of ∼14.5% and an average efficiency of ∼13.5%, with excellent reproducibility.

What governs the enrichment of Pb in the continental crust? An answer from the Mexican Volcanic Belt

NASA Astrophysics Data System (ADS)

Goldstein, S. L.; Lagatta, A.; Langmuir, C. H.; Straub, S. M.; Martin-Del-Pozzo, A.

2009-12-01

One of Al Hofmann’s many important contributions to our understanding of geochemical cycling in the Earth is the observation that Pb behaves like the light rare earth elements Ce and Nd during melting to form oceanic basalts, but is enriched in the continental crust compared to the LREE by nearly an order of magnitude (Hofmann et al. 1986). This is unusual behavior, and has been called one of the Pb paradoxes, since in most cases, the ratios of elements are effectively the same in the continental crust and oceanic basalts if they show similar mantle melting behavior. One of several mechanisms suggested to mediate this special enrichment is hydrothermal circulation at ocean ridges, which preferentially transports Pb compared to the REE from the interior of the ocean crust to the surface. We confirm the importance of hydrothermal processes at the East Pacific to mediate Pb enrichment at the Trans-Mexican Volcanic Belt (TMVB, through comparison of Pb isotope and Ce/Pb ratios of TMVB lavas with sediments from DSDP Site 487 near the Middle America trench. The lavas of the Trans-Mexican Volcanic Belt include “high Nb” alkali basalts (HNAB), whose trace element patterns lack subduction signatures. The HNAB basalts and hydrothermally affected sediments from DSDP 487, form end-members that bound calcalkaline lavas from volcanoes Colima, Toluca, Popocatépetl, and Malinche in Ce/Pb versus Pb isotope space. The HNAB represent the high Ce/Pb and high Pb-isotope end-member. The hydrothermal sediments have Pb isotopes like Pacific MORB but Ce/Pb ratios typical of the arcs and the continental crust, and an order of magnitude lower than MORB. No analyzed calcalkaline lavas are have compositions outside of the bounds formed by the HNAB and the hydrothermal sediments. The Ce/Pb and Pb isotope ratios show that the calcalkaline lava compositions are inconsistent with contributions from HNAB and EPR MORB, rather the contributions are from HNAB upper mantle and subducted hydrothermal sediments. The Trans-Mexican Volcanic Belt data confirm the two-step process of Pb enrichment in the arc lavas (and more generally in the continental crust). In the first step, hydrothermal processes at the East Pacific Rise preferentially transport Pb from the basaltic oceanic crust to surface sediments. In the second step, during subduction, these sediments are the main source of asthenospheric mantle-derived Pb to the lavas. Our data also confirm the importance of subduction contributions to the Quaternary Mexican arc, despite the >40 km thick continental crust. Ref: Hofmann et al. (1986) EPSL 79 p. 33-45.

Age-related changes in gait adaptability in response to unpredictable obstacles and stepping targets.

PubMed

Caetano, Maria Joana D; Lord, Stephen R; Schoene, Daniel; Pelicioni, Paulo H S; Sturnieks, Daina L; Menant, Jasmine C

2016-05-01

A large proportion of falls in older people occur when walking. Limitations in gait adaptability might contribute to tripping; a frequently reported cause of falls in this group. To evaluate age-related changes in gait adaptability in response to obstacles or stepping targets presented at short notice, i.e.: approximately two steps ahead. Fifty older adults (aged 74±7 years; 34 females) and 21 young adults (aged 26±4 years; 12 females) completed 3 usual gait speed (baseline) trials. They then completed the following randomly presented gait adaptability trials: obstacle avoidance, short stepping target, long stepping target and no target/obstacle (3 trials of each). Compared with the young, the older adults slowed significantly in no target/obstacle trials compared with the baseline trials. They took more steps and spent more time in double support while approaching the obstacle and stepping targets, demonstrated poorer stepping accuracy and made more stepping errors (failed to hit the stepping targets/avoid the obstacle). The older adults also reduced velocity of the two preceding steps and shortened the previous step in the long stepping target condition and in the obstacle avoidance condition. Compared with their younger counterparts, the older adults exhibited a more conservative adaptation strategy characterised by slow, short and multiple steps with longer time in double support. Even so, they demonstrated poorer stepping accuracy and made more stepping errors. This reduced gait adaptability may place older adults at increased risk of falling when negotiating unexpected hazards. Copyright © 2016 Elsevier B.V. All rights reserved.

Motivation and value influences in the relative balance of goal-directed and habitual behaviours in obsessive-compulsive disorder.

PubMed

Voon, V; Baek, K; Enander, J; Worbe, Y; Morris, L S; Harrison, N A; Robbins, T W; Rück, C; Daw, N

2015-11-03

Our decisions are based on parallel and competing systems of goal-directed and habitual learning, systems which can be impaired in pathological behaviours. Here we focus on the influence of motivation and compare reward and loss outcomes in subjects with obsessive-compulsive disorder (OCD) on model-based goal-directed and model-free habitual behaviours using the two-step task. We further investigate the relationship with acquisition learning using a one-step probabilistic learning task. Forty-eight OCD subjects and 96 healthy volunteers were tested on a reward and 30 OCD subjects and 53 healthy volunteers on the loss version of the two-step task. Thirty-six OCD subjects and 72 healthy volunteers were also tested on a one-step reversal task. OCD subjects compared with healthy volunteers were less goal oriented (model-based) and more habitual (model-free) to reward outcomes with a shift towards greater model-based and lower habitual choices to loss outcomes. OCD subjects also had enhanced acquisition learning to loss outcomes on the one-step task, which correlated with goal-directed learning in the two-step task. OCD subjects had greater stay behaviours or perseveration in the one-step task irrespective of outcome. Compulsion severity was correlated with habitual learning in the reward condition. Obsession severity was correlated with greater switching after loss outcomes. In healthy volunteers, we further show that greater reward magnitudes are associated with a shift towards greater goal-directed learning further emphasizing the role of outcome salience. Our results highlight an important influence of motivation on learning processes in OCD and suggest that distinct clinical strategies based on valence may be warranted.

Thermal quenching effect of an infrared deep level in Mg-doped p-type GaN films

NASA Astrophysics Data System (ADS)

Kim, Keunjoo; Chung, Sang Jo

2002-03-01

The thermal quenching of an infrared deep level of 1.2-1.5 eV has been investigated on Mg-doped p-type GaN films, using one- and two-step annealing processes and photocurrent measurements. The deep level appeared in the one-step annealing process at a relatively high temperature of 900 °C, but disappeared in the two-step annealing process with a low-temperature step and a subsequent high-temperature step. The persistent photocurrent was residual in the sample including the deep level, while it was terminated in the sample without the deep level. This indicates that the deep level is a neutral hole center located above a quasi-Fermi level, estimated with an energy of EpF=0.1-0.15 eV above the valence band at a hole carrier concentration of 2.0-2.5×1017/cm3.

Modeling behavior dynamics using computational psychometrics within virtual worlds.

PubMed

Cipresso, Pietro

2015-01-01

In case of fire in a building, how will people behave in the crowd? The behavior of each individual affects the behavior of others and, conversely, each one behaves considering the crowd as a whole and the individual others. In this article, I propose a three-step method to explore a brand new way to study behavior dynamics. The first step relies on the creation of specific situations with standard techniques (such as mental imagery, text, video, and audio) and an advanced technique [Virtual Reality (VR)] to manipulate experimental settings. The second step concerns the measurement of behavior in one, two, or many individuals focusing on parameters extractions to provide information about the behavior dynamics. Finally, the third step, which uses the parameters collected and measured in the previous two steps in order to simulate possible scenarios to forecast through computational models, understand, and explain behavior dynamics at the social level. An experimental study was also included to demonstrate the three-step method and a possible scenario.

Opaque cloud detection

DOEpatents

Roskovensky, John K [Albuquerque, NM

2009-01-20

A method of detecting clouds in a digital image comprising, for an area of the digital image, determining a reflectance value in at least three discrete electromagnetic spectrum bands, computing a first ratio of one reflectance value minus another reflectance value and the same two values added together, computing a second ratio of one reflectance value and another reflectance value, choosing one of the reflectance values, and concluding that an opaque cloud exists in the area if the results of each of the two computing steps and the choosing step fall within three corresponding predetermined ranges.

Blastocyst utilization rates after continuous culture in two commercial single-step media: a prospective randomized study with sibling oocytes.

PubMed

Sfontouris, Ioannis A; Kolibianakis, Efstratios M; Lainas, George T; Venetis, Christos A; Petsas, George K; Tarlatzis, Basil C; Lainas, Tryfon G

2017-10-01

The aim of this study is to determine whether blastocyst utilization rates are different after continuous culture in two different commercial single-step media. This is a paired randomized controlled trial with sibling oocytes conducted in infertility patients, aged ≤40 years with ≥10 oocytes retrieved assigned to blastocyst culture and transfer. Retrieved oocytes were randomly allocated to continuous culture in either Sage one-step medium (Origio) or Continuous Single Culture (CSC) medium (Irvine Scientific) without medium renewal up to day 5 post oocyte retrieval. Main outcome measure was the proportion of embryos suitable for clinical use (utilization rate). A total of 502 oocytes from 33 women were randomly allocated to continuous culture in either Sage one-step medium (n = 250) or CSC medium (n = 252). Fertilization was performed by either in vitro fertilization or intracytoplasmic sperm injection, and embryo transfers were performed on day 5. Two patients had all blastocysts frozen due to the occurrence of severe ovarian hyperstimulation syndrome. Fertilization and cleavage rates, as well as embryo quality on day 3, were similar in the two media. Blastocyst utilization rates (%, 95% CI) [55.4% (46.4-64.1) vs 54.7% (44.9-64.6), p = 0.717], blastocyst formation rates [53.6% (44.6-62.5) vs 51.9 (42.2-61.6), p = 0.755], and proportion of good quality blastocysts [36.8% (28.1-45.4) vs 36.1% (27.2-45.0), p = 0.850] were similar in Sage one-step and CSC media, respectively. Continuous culture of embryos in Sage one-step and CSC media is associated with similar blastocyst development and utilization rates. Both single-step media appear to provide adequate support during in vitro preimplantation embryo development. Whether these observations are also valid for other continuous single medium protocols remains to be determined. NCT02302638.

Controlling CH3NH3PbI(3-x)Cl(x) Film Morphology with Two-Step Annealing Method for Efficient Hybrid Perovskite Solar Cells.

PubMed

Liu, Dong; Wu, Lili; Li, Chunxiu; Ren, Shengqiang; Zhang, Jingquan; Li, Wei; Feng, Lianghuan

2015-08-05

The methylammonium lead halide perovskite solar cells have become very attractive because they can be prepared with low-cost solution-processable technology and their power conversion efficiency have been increasing from 3.9% to 20% in recent years. However, the high performance of perovskite photovoltaic devices are dependent on the complicated process to prepare compact perovskite films with large grain size. Herein, a new method is developed to achieve excellent CH3NH3PbI3-xClx film with fine morphology and crystallization based on one step deposition and two-step annealing process. This method include the spin coating deposition of the perovskite films with the precursor solution of PbI2, PbCl2, and CH3NH3I at the molar ratio 1:1:4 in dimethylformamide (DMF) and the post two-step annealing (TSA). The first annealing is achieved by solvent-induced process in DMF to promote migration and interdiffusion of the solvent-assisted precursor ions and molecules and realize large size grain growth. The second annealing is conducted by thermal-induced process to further improve morphology and crystallization of films. The compact perovskite films are successfully prepared with grain size up to 1.1 μm according to SEM observation. The PL decay lifetime, and the optic energy gap for the film with two-step annealing are 460 ns and 1.575 eV, respectively, while they are 307 and 327 ns and 1.577 and 1.582 eV for the films annealed in one-step thermal and one-step solvent process. On the basis of the TSA process, the photovoltaic devices exhibit the best efficiency of 14% under AM 1.5G irradiation (100 mW·cm(-2)).

Independent influence of gait speed and step length on stability and fall risk.

PubMed

Espy, D D; Yang, F; Bhatt, T; Pai, Y-C

2010-07-01

With aging, individuals' gaits become slower and their steps shorter; both are thought to improve stability against balance threats. Recent studies have shown that shorter step lengths, which bring the center of mass (COM) closer to the leading foot, improve stability against slip-related falls. However, a slower gait, hence lower COM velocity, does the opposite. Due to the inherent coupling of step length and speed in spontaneous gait, the extent to which the benefit of shorter steps can offset the slower speed is unknown. The purpose of this study was to investigate, through decoupling, the independent effects of gait speed and step length on gait stability and the likelihood of slip-induced falls. Fifty-seven young adults walked at one of three target gait patterns, two of equal speed and two of equal step length; at a later trial, they encountered an unannounced slip. The results supported our hypotheses that faster gait as well as shorter steps each ameliorates fall risk when a slip is encountered. This appeared to be attributable to the maintenance of stability from slip initiation to liftoff of the recovery foot during the slip. Successful decoupling of gait speed from step length reveals for the first time that, although slow gait in itself leads to instability and falls (a one-standard-deviation decrease in gait speed increases the odds of fall by 4-fold), this effect is offset by the related decrease in step length (the same one-standard-deviation decrease in step length lowers fall risk by 6 times). Copyright © 2010 Elsevier B.V. All rights reserved.

Influence of the Supramolecular Micro-Assembly of Multiple Emulsions on their Biopharmaceutical Features and In vivo Therapeutic Response.

PubMed

Cilurzo, Felisa; Cristiano, Maria Chiara; Di Marzio, Luisa; Cosco, Donato; Carafa, Maria; Ventura, Cinzia Anna; Fresta, Massimo; Paolino, Donatella

2015-01-01

The ability of some surfactants to self-assemble in a water/oil bi-phase environment thus forming supramolecular structure leading to the formation of w/o/w multiple emulsions was investigated. The w/o/w multiple emulsions obtained by self-assembling (one-step preparation method) were compared with those prepared following the traditional two-step procedure. Methyl-nicotinate was used as a hydrophilic model drug. The formation of the multiple emulsion structure was evidenced by optical microscopy, which showed a mean size of the inner oil droplets of 6 μm and 10 μm for one-step and two-step multiple emulsions, respectively. The in vitrobiopharmaceutical features of the various w/o/w multiple emulsion formulations were evaluated by means of viscosimetry studies, drug release and in vitro percutaneous permeation experiments through human stratum corneum and viable epidermis membranes. The self-assembled multiple emulsions allowed a more gradual percutaneous permeation (a zero-order permeation rate) than the two-step ones. The in vivotopical carrier properties of the two different multiple emulsions were evaluated on healthy human volunteers by using the spectrophotometry of reflectance, an in vivonon invasive method. These multiple emulsion systems were also compared with conventional emulsion formulations. Our findings demonstrated that the multiple emulsions obtained by self-assembling were able to provide a more sustained drug delivery into the skin and hence a longer therapeutic action than two-step multiple emulsions and conventional emulsion formulations. Finally, our findings showed that the supramolecular micro-assembly of multiple emulsions was able to influence not only the biopharmaceutical characteristics but also the potential in vivotherapeutic response.

30 CFR 7.302 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... conduit box when specified. A motor assembly is comprised of one or more explosion-proof enclosures. Plane joint. A joint comprised of two adjoining surfaces in parallel planes. Step (rabbet) joint. A joint.... A step joint may be composed of a cylindrical portion and a plane portion or of two or more plane...

Resolving the infection process reveals striking differences in the contribution of environment, genetics and phylogeny to host-parasite interactions

PubMed Central

2011-01-01

Background Infection processes consist of a sequence of steps, each critical for the interaction between host and parasite. Studies of host-parasite interactions rarely take into account the fact that different steps might be influenced by different factors and might, therefore, make different contributions to shaping coevolution. We designed a new method using the Daphnia magna - Pasteuria ramosa system, one of the rare examples where coevolution has been documented, in order to resolve the steps of the infection and analyse the factors that influence each of them. Results Using the transparent Daphnia hosts and fluorescently-labelled spores of the bacterium P. ramosa, we identified a sequence of infection steps: encounter between parasite and host; activation of parasite dormant spores; attachment of spores to the host; and parasite proliferation inside the host. The chances of encounter had been shown to depend on host genotype and environment. We tested the role of genetic and environmental factors in the newly described activation and attachment steps. Hosts of different genotypes, gender and species were all able to activate endospores of all parasite clones tested in different environments; suggesting that the activation cue is phylogenetically conserved. We next established that parasite attachment occurs onto the host oesophagus independently of host species, gender and environmental conditions. In contrast to spore activation, attachment depended strongly on the combination of host and parasite genotypes. Conclusions Our results show that different steps are influenced by different factors. Host-type-independent spore activation suggests that this step can be ruled out as a major factor in Daphnia-Pasteuria coevolution. On the other hand, we show that the attachment step is crucial for the pronounced genetic specificities of this system. We suggest that this one step can explain host population structure and could be a key force behind coevolutionary cycles. We discuss how different steps can explain different aspects of the coevolutionary dynamics of the system: the properties of the attachment step, explaining the rapid evolution of infectivity and the properties of later parasite proliferation explaining the evolution of virulence. Our study underlines the importance of resolving the infection process in order to better understand host-parasite interactions. PMID:21342515

Enhanced removal of bisphenol-AF by activated carbon-alginate beads with cetyltrimethyl ammonium bromide.

PubMed

Tang, Zheng; Peng, Sha; Hu, Shuya; Hong, Song

2017-06-01

Adsorption removal of bisphenol-AF (BPAF) from aqueous solutions by synthesized activated carbon-alginate beads (AC-AB) with cetyltrimethyl ammonium bromide (CTAB) has been studied using two ways. The traditional method (two-step) first synthesized CTAB-modified AC-AB (AC-AB-CTAB), then used it to remove BPAF by adsorption. And one-step method dispersed AC-AB and CTAB in wastewater, followed by the removal of BPAF accompanied with the synthesis of AC-AB-CTAB. The one-step method showed a better performance than the two-step method, achieving a maximum removal of BPAF with 284.6mg/g. Kinetic studies and adsorption isotherms indicated that adsorption process of BPAF on AC-AB by the one-step method could be expressed by a pseudo-second-order model and a Dubinin-Ashtakhov (D-A) isotherm, respectively. The effects of pH, ionic strength, and inorganic ions on BPAF adsorption were also investigated. Furthermore, hydrophobic interactions, hydrogen bonds, and π-π electron donor-acceptor (EDA) interactions were discussed to explain the enhanced adsorption behavior of BPAF on AC-AB with CTAB. The findings verified the effectiveness of AC-AB for the removal of BPAF from wastewater and its high stability within five regeneration cycles. Copyright © 2017 Elsevier Inc. All rights reserved.

The meaning of suffering in drug addiction and recovery from the perspective of existentialism, Buddhism and the 12-Step program.

PubMed

Chen, Gila

2010-09-01

The aim of the current article was to examine the meaning of suffering in drug addiction and in the recovery process. Negative emotions may cause primary suffering that can drive an individual toward substance abuse. At the same time, drugs only provide temporary relief, and over time, the pathological effects of the addiction worsen causing secondary suffering, which is a motivation for treatment. The 12-Step program offers a practical way to cope with suffering through a process of surrender. The act of surrender sets in motion a conversion experience, which involves a self-change including reorganization of one's identity and meaning in life. This article is another step toward understanding one of the several factors that contribute to the addict's motivation for treatment. This knowledge may be helpful for tailoring treatment that addresses suffering as a factor that initiates treatment motivation and, in turn, treatment success.

One-pot, two-step desymmetrization of symmetrical benzils catalyzed by the methylsulfinyl (dimsyl) anion.

PubMed

Ragno, Daniele; Bortolini, Olga; Giovannini, Pier Paolo; Massi, Alessandro; Pacifico, Salvatore; Zaghi, Anna

2014-08-14

An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure. Both electron-withdrawing and electron-donating substituents may be accommodated on the aromatic rings of the final unsymmetrical benzil.

Spin-Precession Organic Magnetic Sensor

DTIC Science & Technology

2012-06-01

magnetically— a new half-metal CFAS that has desirable properties for use at room temperature; (2) fabricated several nonlocal devices with CFAS and polymer...400 600 800 1000 1200 0 200 400 600 800 Temperature ( C) M s (e m u /c c) One-Step Two-Step Figure 2: Magnetic properties of CFAS layers measured...temperature-independent for the two-step process. We also measured the transport properties of CFAS layers. The electrical resistivity is small (~60

Two-step narrow ridge cascade diode lasers emitting near $$2~\\mu$$ m

DOE PAGES

Feng, Tao; Hosoda, Takashi; Shterengas, Leon; ...

2017-01-02

Nearly diffraction limited GaSb-based type-I quantum well cascade diode lasers emitting in the spectral region 1.95-2 μm were designed and fabricated. Two-step 5.5-μm-wide shallow and 14-μm-wide deep etched ridge waveguide design yielded devices generating stable single lobe beams with 250 mW of continuous wave output power at 20 °C. Quantum well radiative recombination current contributes about 13% to laser threshold as estimated from true spontaneous emission and modal gain analysis. Here, recombination at etched sidewalls of the 14-μmwide deep ridges controls about 30% of the threshold.

Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

NASA Astrophysics Data System (ADS)

Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

2018-02-01

We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

Method to produce alumina aerogels having porosities greater than 80 percent

DOEpatents

Poco, John F.; Hrubesh, Lawrence W.

2003-09-16

A two-step method for producing monolithic alumina aerogels having porosities of greater than 80 percent. Very strong, very low density alumina aerogel monoliths are prepared using the two-step sol-gel process. The method of preparing pure alumina aerogel modifies the prior known sol method by combining the use of substoichiometric water for hydrolysis, the use of acetic acid to control hydrolysis/condensation, and high temperature supercritical drying, all of which contribute to the formation of a polycrystalline aerogel microstructure. This structure provides exceptional mechanical properties of the alumina aerogel, as well as enhanced thermal resistance and high temperature stability.

Nondestructive mechanical characterization of developing biological tissues using inflation testing.

PubMed

Oomen, P J A; van Kelle, M A J; Oomens, C W J; Bouten, C V C; Loerakker, S

2017-10-01

One of the hallmarks of biological soft tissues is their capacity to grow and remodel in response to changes in their environment. Although it is well-accepted that these processes occur at least partly to maintain a mechanical homeostasis, it remains unclear which mechanical constituent(s) determine(s) mechanical homeostasis. In the current study a nondestructive mechanical test and a two-step inverse analysis method were developed and validated to nondestructively estimate the mechanical properties of biological tissue during tissue culture. Nondestructive mechanical testing was achieved by performing an inflation test on tissues that were cultured inside a bioreactor, while the tissue displacement and thickness were nondestructively measured using ultrasound. The material parameters were estimated by an inverse finite element scheme, which was preceded by an analytical estimation step to rapidly obtain an initial estimate that already approximated the final solution. The efficiency and accuracy of the two-step inverse method was demonstrated on virtual experiments of several material types with known parameters. PDMS samples were used to demonstrate the method's feasibility, where it was shown that the proposed method yielded similar results to tensile testing. Finally, the method was applied to estimate the material properties of tissue-engineered constructs. Via this method, the evolution of mechanical properties during tissue growth and remodeling can now be monitored in a well-controlled system. The outcomes can be used to determine various mechanical constituents and to assess their contribution to mechanical homeostasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

One-step aluminium-assisted crystallization of Ge epitaxy on Si by magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ziheng, E-mail: ziheng.liu@unsw.edu.au; Hao, Xiaojing; Ho-Baillie, Anita

In this work, one-step aluminium-assisted crystallization of Ge on Si is achieved via magnetron sputtering by applying an in-situ low temperature (50 °C to 150 °C) heat treatment in between Al and Ge depositions. The effect of heat treatment on film properties and the growth mechanism of Ge epitaxy on Si are studied via X-ray diffraction, Raman and transmission electron microscopy analyses. Compared with the conventional two-step process, the one-step aluminium-assisted crystallization requires much lower thermal budget and results in pure Ge epitaxial layer, which may be suitable for use as a virtual substrate for the fabrication of III-V solar cells.

The prevalence of upright non-stepping time in comparison to stepping time in 11-13 year old school children across seasons.

PubMed

McCrorie, P Rw; Duncan, E; Granat, M H; Stansfield, B W

2012-11-01

Evidence suggests that behaviours such as standing are beneficial for our health. Unfortunately, little is known of the prevalence of this state, its importance in relation to time spent stepping or variation across seasons. The aim of this study was to quantify, in young adolescents, the prevalence and seasonal changes in time spent upright and not stepping (UNSt(time)) as well as time spent upright and stepping (USt(time)), and their contribution to overall upright time (U(time)). Thirty-three adolescents (12.2 ± 0.3 y) wore the activPAL activity monitor during four school days on two occasions: November/December (winter) and May/June (summer). UNSt(time) contributed 60% of daily U(time) at winter (Mean = 196 min) and 53% at summer (Mean = 171 min); a significant seasonal effect, p < 0.001. USt(time) was significantly greater in summer compared to winter (153 min versus 131 min, p < 0.001). The effects in UNSt(time) could be explained through significant seasonal differences during the school hours (09:00-16:00), whereas the effects in USt(time) could be explained through significant seasonal differences in the evening period (16:00-22:00). Adolescents spent a greater amount of time upright and not stepping than they did stepping, in both winter and summer. The observed seasonal effects for both UNSt(time) and USt(time) provide important information for behaviour change intervention programs.

Lateral step initiation behavior in older adults.

PubMed

Sparto, Patrick J; Jennings, J Richard; Furman, Joseph M; Redfern, Mark S

2014-02-01

Older adults have varied postural responses during induced and voluntary lateral stepping. The purpose of the research was to quantify the occurrence of different stepping strategies during lateral step initiation in older adults and to relate the stepping responses to retrospective history of falls. Seventy community-ambulating older adults (mean age 76 y, range 70-94 y) performed voluntary lateral steps as quickly as possible to the right or left in response to a visual cue, in a blocked design. Vertical ground reaction forces were measured using a forceplate, and the number and latency of postural adjustments were quantified. Subjects were assigned to groups based on their stepping strategy. The frequency of trials with one or two postural adjustments was compared with data from 20 younger adults (mean age 38 y, range 21-58 y). Logistic regression was used to relate presence of a fall in the previous year with the number and latency of postural adjustments. In comparison with younger adults, who almost always demonstrated one postural adjustment when stepping laterally, older adults constituted a continuous distribution in the percentage of step trials made with one postural adjustment (from 0% to 100% of trials). Latencies of the initial postural adjustment and foot liftoff varied depending on the number of postural adjustments made. A history of falls was associated a larger percentage of two postural adjustments, and a longer latency of foot liftoff. In conclusion, the number and latency of postural adjustments made during voluntary lateral stepping provides additional evidence that lateral control of posture may be a critical indicator of aging. Copyright © 2013 Elsevier B.V. All rights reserved.

Lateral step initiation behavior in older adults

PubMed Central

Sparto, Patrick J; Jennings, J Richard; Furman, Joseph M; Redfern, Mark S

2013-01-01

Older adults have varied postural responses during induced and voluntary lateral stepping. The purpose of the research was to quantify the occurrence of different stepping strategies during lateral step initiation in older adults and to relate the stepping responses to retrospective history of falls. Seventy community-ambulating older adults (mean age 76 y, range 70–94 y) performed voluntary lateral steps as quickly as possible to the right or left in response to a visual cue, in a blocked design. Vertical ground reaction forces were measured using a forceplate, and the number and latency of postural adjustments were quantified. Subjects were assigned to groups based on their stepping strategy. The frequency of trials with one or two postural adjustments was compared with data from 20 younger adults (mean age 38 y, range 21–58 y). Logistic regression was used to relate presence of a fall in the previous year with the number and latency of postural adjustments. In comparison with younger adults, who almost always demonstrated one postural adjustment when stepping laterally, older adults constituted a continuous distribution in the percentage of step trials made with one postural adjustment (from 0% to 100% of trials). Latencies of the initial postural adjustment and foot liftoff varied depending on the number of postural adjustments made. A history of falls was associated a larger percentage of two postural adjustments, and a longer latency of foot liftoff. In conclusion, the number and latency of postural adjustments made during voluntary lateral stepping provides additional evidence that lateral control of posture may be a critical indicator of aging. PMID:24295896

Theory of multiexciton dynamics in molecular chains

NASA Astrophysics Data System (ADS)

Wang, Luxia; May, Volkhard

2016-11-01

Ultrafast and strong optical excitation of a molecular system is considered which is formed by a regular one-dimensional arrangement of identical molecules. As it is typical for zinc chlorine-type molecules the transition energy from the ground state to the first excited singlet state is assumed to be smaller than the energy difference between the first excited state and the following one. This enables the creation of many excitons without their immediate quenching due to exciton-exciton annihilation. As a first step into the field of dense Frenkel-exciton systems the present approach stays at a mean-field type of description and ignores vibrational contributions. The resulting nonlinear kinetic equations mix Rabi-type oscillations with those caused by energy transfer and suggest an excitation-dependent narrowing of the exciton band. The indication of this effect in the framework of a two-color pump-probe experiment and of the detection of photon emission is discussed.

Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zajnulina, M.; Giannone, D.; Haynes, R.

We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromaticmore » input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.« less

Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers.

PubMed

Zajnulina, M; Böhm, M; Blow, K; Rieznik, A A; Giannone, D; Haynes, R; Roth, M M

2015-10-01

We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.

Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

NASA Astrophysics Data System (ADS)

Zajnulina, M.; Böhm, M.; Blow, K.; Rieznik, A. A.; Giannone, D.; Haynes, R.; Roth, M. M.

2015-10-01

We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.

Mapping of within-species segregation distortion in D. persimilis and hybrid sterility between D. persimilis and D. pseudoobscura

PubMed Central

McDermott, Shannon R.; Noor, Mohamed A. F.

2012-01-01

In contrast to the prevailing dogma in the 1990s, recent studies have suggested that an evolutionary history of segregation distortion within species may contribute to sterility in species hybrids. However, this recent work identified segregation distortion exclusively in species hybrids which may never have had an evolutionary history of segregation distortion in either parent species. We expand on previous work by using a strain of Drosophila persimilis exhibiting segregation distortion within species to generate QTL maps for segregation distortion and hybrid sterility in crosses between D. persimilis and D. pseudoobscura. The maps localize regions along the XR contributing to both phenotypes, and they indicate one region of overlap between the two maps. This overlap could provide preliminary evidence for an association between segregation distortion within species and hybrid sterility, but the localizations are currently too broad to have confidence in this conclusion. This work is a first step towards possibly supporting a genetic conflict model of speciation in this system. PMID:22966762

Types of Rural Extensionists' Expectations of Psychology and Their Implications on Psychologists' Practice.

PubMed

Landini, Fernando

2016-12-01

Psychology has great potential for contributing to rural development, particularly through supporting rural extension (RE). In this paper, the types of expectations extensionists have of psychology are identified, as well as possible ways of integrating psychosocial knowledge into the RE context. Rural extensionists from 12 Latin American countries were surveyed (n = 654). Of them, 89.4 % considered psychology could contribute to rural extension and commented on how this would be possible. Expectations were categorised and the nine mentioned by more than 20 % of them were utilized to conduct a two-steps cluster analysis. Three types of extensionists' expectations were identified: one wherein working with extensionists was highlighted; another characterised by a focus on working with farmers; and a third featuring a traditional, diffusionist extension approach, which views farmers as objects of psychologists' interventions. With the first type, psychologists should not neglect working with farmers and with the second, with extensionists. With the third type, reflecting on the expectations themselves and their underlying assumptions seems essential.

Shear bond strength of one-step self-etch adhesives to enamel: effect of acid pretreatment.

PubMed

Poggio, Claudio; Scribante, Andrea; Della Zoppa, Federica; Colombo, Marco; Beltrami, Riccardo; Chiesa, Marco

2014-02-01

The purposes of this study were to evaluate the effect of surface pretreatment with phosphoric acid on the enamel bond strength of four-one-step self-etch adhesives with different pH values. One hundred bovine permanent mandibular incisors were used. The materials used in this study included four-one-step self-etch adhesives with different pH values: Adper(™) Easy Bond Self-Etch Adhesive (ph = 0,8-1), Futurabond NR (ph = 1,4), G-aenial Bond (ph = 1,5), Clearfil(3) S Bond (ph = 2,7). One two-step self-etch adhesive (Clearfil SE Bond/ph = 0,8-1) was used as control. The teeth were assigned into two subgroups according to bonding procedure. In the first subgroup (n = 50), no pretreatment agent was applied. In the second subgroup (n = 50), etching was performed using 37% phosphoric acid for 30 s. After adhesive systems application, a nanohybrid composite resin was inserted into the enamel surface. The specimens were placed in a universal testing machine (Model 3343, Instron Corp., Canton, Mass., USA). After the testing procedure, the fractured surfaces were examined with an optical microscope at a magnification of 10× to determine failure modes. The adhesive remnant index (ARI) was used to assess the amount of adhesive left on the enamel surface. Descriptive statistics of the shear bond strength and frequency distribution of ARI scores were calculated. Enamel pretreatment with phosphoric acid significantly increased bond strength values of all the adhesives tested. No significant differences in bond strength were detected among the four different one-step self-etch adhesives with different pH. Two-step self-etch adhesive showed the highest bond strength. © 2013 John Wiley & Sons A/S.

Design of polynomial fuzzy observer-controller for nonlinear systems with state delay: sum of squares approach

NASA Astrophysics Data System (ADS)

Gassara, H.; El Hajjaji, A.; Chaabane, M.

2017-07-01

This paper investigates the problem of observer-based control for two classes of polynomial fuzzy systems with time-varying delay. The first class concerns a special case where the polynomial matrices do not depend on the estimated state variables. The second one is the general case where the polynomial matrices could depend on unmeasurable system states that will be estimated. For the last case, two design procedures are proposed. The first one gives the polynomial fuzzy controller and observer gains in two steps. In the second procedure, the designed gains are obtained using a single-step approach to overcome the drawback of a two-step procedure. The obtained conditions are presented in terms of sum of squares (SOS) which can be solved via the SOSTOOLS and a semi-definite program solver. Illustrative examples show the validity and applicability of the proposed results.

Effect of sonic application mode on the resin-dentin bond strength and dentin permeability of self-etching systems.

PubMed

Mena-Serrano, Alexandra; Costa, Thays Regina Ferreira da; Patzlaff, Rafael Tiago; Loguercio, Alessandro Dourado; Reis, Alessandra

2014-10-01

To compare manual and sonic adhesive application modes in terms of the permeability and microtensile bond strength of a self-etching adhesive applied in the one-step or two-step protocol. Self-etching All Bond SE (Bisco) was applied as a one- or a two-step adhesive under manual or sonic vibration modes on flat occlusal dentin surfaces of 64 human molars. Half of the teeth were used to measure the hydraulic conductance of dentin at 200 cm H₂O hydrostatic pressure for 5 min immediately after the adhesive application. In the other half, composite buildups (Opallis) were constructed incrementally to create resin-dentin sticks with a cross-sectional area of 0.8 mm² to be tested in tension (0.5 mm/min) immediately after restoration placement. Data were analyzed using a two-way ANOVA and Tukey's test (α = 0.05). The fluid conductance of dentin was significantly reduced by the sonic vibration mode for both adhesives, but no effect on the bond strength values was observed for either adhesive. The sonic application mode at an oscillating frequency of 170 Hz can reduce the fluid conductance of the one- and two-step All Bond SE adhesive when applied on dentin.

One Step Forward, Two Steps Back? The Professionalisation of Further Education Teachers in England

ERIC Educational Resources Information Center

Lucas, Norman

2013-01-01

This paper draws upon two research projects to evaluate a decade of reform concerning the professionalisation of further education teachers, and discusses future prospects under the new coalition government. It suggests that policy initiatives to regulate further education (FE) teachers have taken place within an industrial or occupational…

Fungal bioleaching of WPCBs using Aspergillus niger: Observation, optimization and kinetics.

PubMed

Faraji, Fariborz; Golmohammadzadeh, Rabeeh; Rashchi, Fereshteh; Alimardani, Navid

2018-07-01

In this study, Aspergillus niger (A. niger) as an environmentally friendly agent for fungal bioleaching of waste printed circuit boards (WPCBs) was employed. D-optimal response surface methodology (RSM) was utilized for optimization of the bioleaching parameters including bioleaching method (one step, two step and spent medium) and pulp densities (0.5 g L -1 to 20 g L -1 ) to maximize the recovery of Zn, Ni and Cu from WPCBs. According to the high performance liquid chromatography analysis, citric, oxalic, malic and gluconic acids were the most abundant organic acids produced by A.niger in 21 days experiments. Maximum recoveries of 98.57% of Zn, 43.95% of Ni and 64.03% of Cu were achieved based on acidolysis and complexolysis dissolution mechanisms of organic acids. Based on the kinetic studies, the rate controlling mechanism for Zn dissolution at one step approach was found to be diffusion through liquid film, while it was found to be mixed control for both two step and spent medium. Furthermore, rate of Cu dissolution which is controlled by diffusion in one step and two step approaches, detected to be controlled by chemical reaction at spent medium. It was shown that for Ni, the rate is controlled by chemical reaction for all the methods studied. Eventually, it was understood that A. niger is capable of leaching 100% of Zn, 80.39% of Ni and 85.88% of Cu in 30 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

Henri Poincaré and the principle of relativity

NASA Astrophysics Data System (ADS)

Messager, Valérie; Gilmore, Robert; Letellier, Christophe

2012-09-01

Often considered as the last 'encyclopedist', Henri Poincaré died one hundred years ago. If he was a prominent man in 1900 French Society, his heritage is not so clearly recognised, particularly in France. Among his too often misunderstood works is his contribution to the theory of relativity, mainly because it is almost never presented within Poincaré's general approach to science, including his philosophical writings. Our aim is therefore to provide an historical account of the main steps (experimental as well as theoretical) which led Poincaré to contribute to the theory of relativity. Starting from the optical experiments which led to the inconsistency of the classical (Galilean) composition law for velocities to explain light propagation, we introduce the FitzGerald and Lorentz contraction which was viewed as the 'sole hypothesis' to explain the Michelson and Morley experiment. We then show that Poincaré's contribution starts with a discussion of the principles governing the mechanics and was built step by step up to express in all its generality the principle of relativity. Poincaré thus showed the invariance of the Maxwell equations under the Lorentz transformation. In doing so, he also discovered the right composition law for velocities. Poincaré's approach to philosophy is detailed to help the reader to understand what a theory meant to him.

The decoupling of the glass transitions in the two-component p-spin spherical model

NASA Astrophysics Data System (ADS)

Ikeda, Harukuni; Ikeda, Atsushi

2016-07-01

Binary mixtures of large and small particles with a disparate size ratio exhibit a rich phenomenology at their glass transition points. In order to gain insights on such systems, we introduce and study a two-component version of the p-spin spherical spin glass model. We employ the replica method to calculate the free energy and the phase diagram. We show that when the strengths of the interactions of each component are not widely separated, the model has only one glass phase characterized by the conventional one-step replica symmetry breaking. However when the strengths of the interactions are well separated, the model has three glass phases depending on the temperature and component ratio. One is the ‘single’ glass phase in which only the spins of one component are frozen while the spins of the other component remain mobile. This phase is characterized by the one-step replica symmetry breaking. The second is the ‘double’ glass phase obtained by cooling the single glass phase further, in which the spins of the remaining mobile component are also frozen. This phase is characterized by the two-step replica symmetry breaking. The third is also the ‘double’ glass phase, which, however, is formed by the simultaneous freezing of the spins of both components at the same temperatures and is characterized by the one-step replica symmetry breaking. We discuss the implications of these results for the glass transitions of binary mixtures.

Graphical support for comprehending science texts: The contributions of diagram design and text directives

NASA Astrophysics Data System (ADS)

McTigue, Erin M.

The present study examined the combined effect of diagram design and text directives on the comprehension of explanatory science texts for middle school readers. Three types of diagram designs were compared. Each design contained the same graphical representation of a cycle but differed in the labels. The labels indicated either the (a) parts of the, cycle, (b) steps of the cycle, or (c) both the parts and steps. Additionally, there were two conditions of text, both with and without embedded directives. The directives guided the reader to the diagram to help readers integrate the two sources of information. Finally, each of the 189 sixth grade participants read two texts---a life-science text and a physical-science text. Results indicated that for the life-science text both the parts diagrams and the steps diagrams facilitated the readers' comprehension, but that the parts & steps diagram did not. Overall, the directives assisted readers in the life-science text, when they were viewing the complex diagrams: the steps diagram, and the parts & steps diagrams, but not the parts diagram. Directives also helped girls who were reading at the below- and on-grade level, but not the girls reading above-grade level. Neither the diagrams nor directives facilitated comprehension of the physical science text. There was a gender difference favoring boys on the physical science but no gender difference on the life-science text.

Comparison of wrist-worn and hip-worn activity monitors under free living conditions.

PubMed

Hargens, Trent A; Deyarmin, Kayla N; Snyder, Kelsey M; Mihalik, Allison G; Sharpe, Lauren E

2017-04-01

Current recommendations state that individuals engage in 150 min of moderate or 75 min of vigorous intensity physical activity (PA) each week. Commercial PA monitors are becoming popular for everyday use. The accuracy of these devices, however, is not well understood. We sought to examine the accuracy of two commercial devices, one wrist and one hip-worn, under free-living conditions. Twenty-two subjects wore two commercially available devices and one ActiGraph (AG) for seven consecutive days under normal activity. Mean steps per day between all three devices differed significantly. No differences were found in moderate-to-vigorous intensity physical activity (MPVA). Daily energy expenditure (EE) also differed significantly between the AG and the commercial devices. Bland-Altman analysis found poor agreement between the AG and the commercial devices with regards to steps and EE, but good agreement in MVPA. Results suggest that the commercial devices are less accurate in estimating steps and EE. These devices did show good agreement with regards to MVPA, suggesting that they may provide useful feedback for individuals seeking to achieve the current PA guidelines for MVPA. Improvements are needed with regards to steps and EE estimation.

Molecular and Functional Characterization of Odorant-Binding Protein Genes in an Invasive Vector Mosquito, Aedes albopictus

PubMed Central

Deng, Yuhua; Yan, Hui; Gu, Jinbao; Xu, Jiabao; Wu, Kun; Tu, Zhijian; James, Anthony A.; Chen, Xiaoguang

2013-01-01

Aedes albopictus is a major vector of dengue and Chikungunya viruses. Olfaction plays a vital role in guiding mosquito behaviors and contributes to their ability to transmit pathogens. Odorant-binding proteins (OBPs) are abundant in insect olfactory tissues and involved in the first step of odorant reception. While comprehensive descriptions are available of OBPs from Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae, only a few genes from Ae. albopictus have been reported. In this study, twenty-one putative AalbOBP genes were cloned using their homologues in Ae. aegypti to query an Ae. albopictus partial genome sequence. Two antenna-specific OBPs, AalbOBP37 and AalbOBP39, display a remarkable similarity in their overall folding and binding pockets, according to molecular modeling. Binding affinity assays indicated that AalbOBP37 and AalbOBP39 had overlapping ligand affinities and are affected in different pH condition. Electroantennagrams (EAG) and behavioral tests show that these two genes were involved in olfactory reception. An improved understanding of the Ae. albopictus OBPs is expected to contribute to the development of more efficient and environmentally-friendly mosquito control strategies. PMID:23935894

Regulation of X-chromosome dosage compensation in human: mechanisms and model systems.

PubMed

Sahakyan, Anna; Plath, Kathrin; Rougeulle, Claire

2017-11-05

The human blastocyst forms 5 days after one of the smallest human cells (the sperm) fertilizes one of the largest human cells (the egg). Depending on the sex-chromosome contribution from the sperm, the resulting embryo will either be female, with two X chromosomes (XX), or male, with an X and a Y chromosome (XY). In early development, one of the major differences between XX female and XY male embryos is the conserved process of X-chromosome inactivation (XCI), which compensates gene expression of the two female X chromosomes to match the dosage of the single X chromosome of males. Most of our understanding of the pre-XCI state and XCI establishment is based on mouse studies, but recent evidence from human pre-implantation embryo research suggests that many of the molecular steps defined in the mouse are not conserved in human. Here, we will discuss recent advances in understanding the control of X-chromosome dosage compensation in early human embryonic development and compare it to that of the mouse.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'. © 2017 The Author(s).

Microwave-assisted one-step synthesis of white light-emitting carbon dot suspensions

NASA Astrophysics Data System (ADS)

Vanessa, Hinterberger; Wenshuo, Wang; Cornelia, Damm; Simon, Wawra; Martin, Thoma; Wolfgang, Peukert

2018-06-01

In this contribution, we demonstrate that an aqueous solution with adjustable fluorescent color, including white light emission, can be achieved by a rapid one-step microwave synthesis method resulting in a mixture of blue-emitting carbon dots (CDs) and the yellow-emitting 2,3-diaminophenazine (DAP). Aqueous mixtures of o-phenylene-diamine (oPD) and citric acid (CA) are used as precursors. The resulting product structures are analyzed by FT-IR and NMR spectroscopy and the size of the resulting CDs is determined by atomic force microscopy to be 1.1 ± 0.3 nm. The synthesized solution exhibits two fluorescence emission peaks at 430 and 560 nm, which were found to originate from the CDs and DAP, respectively. The intensity ratio of both fluorescence peaks depends on pH, which is driven by the protonation state of DAP. In consequence, the fluorescence emission color of the CD solution can be tuned precisely and reproducibly from blue to white to yellow by careful control of the pH. Finally, at a pH level of 5.4, at which there is equal blue and yellow emission intensity, a white light emitting solution can be successfully produced in a very fast and simple synthesis procedure.

Which type of leader do I support in step-level public good dilemmas? The roles of level of threshold and trust.

PubMed

De Cremer, David

2007-02-01

The present research examined the moderating effect of the level of threshold on people's preferences for different leader types in step-level public good dilemmas. It was assumed that the primary focus of people in step-level public good dilemmas is to make sure that the group surpasses the threshold. Consequently, when the level of threshold is difficult to reach people are expected to provide more support for and cooperate with a leader that monitors and controls the contributions made toward the public good. However, if the threshold is easy to surpass people will focus more on whether the obtained public good or bonus will be distributed according to agreements, suggesting that people will provide more support to and cooperate with a leader that monitors and controls the distribution of the bonus. These predictions were confirmed across two experiments using a step-level public good paradigm with a dichotomous (Study 1) and a continuous (Study 2) contribution choice. Moreover, the results also revealed that perceptions of trust accounted, in part, for the effect of level of threshold on people's leadership preferences.

Special Education: Parent and Student Rights = Educacion Especial: Los Derechos de los Padres y Estudiantes.

ERIC Educational Resources Information Center

Texas Education Agency, Austin. Div. of Special Education Programs.

Intended for parents of children with possible disabilities in Texas, these two combined booklets (one in English and one in Spanish) outline the step-by-step process qualifying the child for special education services and explain the parent's rights and responsibilities under federal and state law. Introductory material includes a letter to…

Effect of thermal aging on the tensile bond strength at reduced areas of seven current adhesives.

PubMed

Baracco, Bruno; Fuentes, M Victoria; Garrido, Miguel A; González-López, Santiago; Ceballos, Laura

2013-07-01

The purpose of this study was to determine the micro-tensile bond strength (MTBS) to dentin of seven adhesive systems (total and self-etch adhesives) after 24 h and 5,000 thermocycles. Dentin surfaces of human third molars were exposed and bonded with two total-etch adhesives (Adper Scotchbond 1 XT and XP Bond), two two-step self-etch adhesives (Adper Scotchbond SE and Filtek Silorane Adhesive System) and three one-step self-etch adhesives (G-Bond, Xeno V and Bond Force). All adhesive systems were applied following manufacturers' instructions. Composite buildups were constructed and the bonded teeth were then stored in water (24 h, 37 °C) or thermocycled (5,000 cycles) before being sectioned and submitted to MTBS test. Two-way ANOVA and subsequent comparison tests were applied at α = 0.05. Characteristic de-bonded specimens were analyzed using scanning electron microscopy (SEM). After 24 h water storage, MTBS values were highest with XP Bond, Adper Scotchbond 1 XT, Filtek Silorane Adhesive System and Adper Scotchbond SE and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. After thermocycling, MTBS values were highest with XP Bond, followed by Filtek Silorane Adhesive System, Adper Scotchbond SE and Adper Scotchbond 1 XT and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. Thermal aging induced a significant decrease in MTBS values with all adhesives tested. The resistance of resin-dentin bonds to thermal-aging degradation was material dependent. One-step self-etch adhesives obtained the lowest MTBS results after both aging treatments, and their adhesive capacity was significantly reduced after thermocycling.

Association of common genetic variants in GPCPD1 with scaling of visual cortical surface area in humans.

PubMed

Bakken, Trygve E; Roddey, J Cooper; Djurovic, Srdjan; Akshoomoff, Natacha; Amaral, David G; Bloss, Cinnamon S; Casey, B J; Chang, Linda; Ernst, Thomas M; Gruen, Jeffrey R; Jernigan, Terry L; Kaufmann, Walter E; Kenet, Tal; Kennedy, David N; Kuperman, Joshua M; Murray, Sarah S; Sowell, Elizabeth R; Rimol, Lars M; Mattingsdal, Morten; Melle, Ingrid; Agartz, Ingrid; Andreassen, Ole A; Schork, Nicholas J; Dale, Anders M; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q; Toga, Arthur W; Beckett, Laurel; Green, Robert C; Saykin, Andrew J; Morris, John; Liu, Enchi; Montine, Tom; Gamst, Anthony; Thomas, Ronald G; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Harvey, Danielle; Kornak, John; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Bandy, Dan; Koeppe, Robert A; Foster, Norm; Reiman, Eric M; Chen, Kewei; Mathis, Chet; Cairns, Nigel J; Taylor-Reinwald, Lisa; Trojanowki, J Q; Shaw, Les; Lee, Virginia M Y; Korecka, Magdalena; Crawford, Karen; Neu, Scott; Foroud, Tatiana M; Potkin, Steven; Shen, Li; Kachaturian, Zaven; Frank, Richard; Snyder, Peter J; Molchan, Susan; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Dolen, Sara; Schneider, Lon S; Pawluczyk, Sonia; Spann, Bryan M; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L; Lord, Joanne L; Johnson, Kris; Doody, Rachelle S; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S; Bell, Karen L; Morris, John C; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Mitsis, Effie; Romirowsky, Aliza; deToledo-Morrell, Leyla; Shah, Raj C; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; Kielb, Stephanie; Rusinek, Henry; de Leon, Mony J; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P Murali; Petrella, Jeffrey R; Coleman, R Edward; Arnold, Steven E; Karlawish, Jason H; Wolk, David; Smith, Charles D; Jicha, Greg; Hardy, Peter; Lopez, Oscar L; Oakley, MaryAnn; Simpson, Donna M; Porsteinsson, Anton P; Goldstein, Bonnie S; Martin, Kim; Makino, Kelly M; Ismail, M Saleem; Brand, Connie; Mulnard, Ruth A; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I; Lah, James J; Cellar, Janet S; Burns, Jeffrey M; Anderson, Heather S; Swerdlow, Russell H; Apostolova, Liana; Lu, Po H; Bartzokis, George; Silverman, Daniel H S; Graff-Radford, Neill R; Parfitt, Francine; Johnson, Heather; Farlow, Martin R; Hake, Ann Marie; Matthews, Brandy R; Herring, Scott; van Dyck, Christopher H; Carson, Richard E; MacAvoy, Martha G; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Ging-Yuek; Hsiung, Robin; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristina; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A; Johnson, Keith A; Marshall, Gad; Frey, Meghan; Yesavage, Jerome; Taylor, Joy L; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan; Belden, Christine; Jacobson, Sandra; Kowall, Neil; Killiany, Ronald; Budson, Andrew E; Norbash, Alexander; Johnson, Patricia Lynn; Obisesan, Thomas O; Wolday, Saba; Bwayo, Salome K; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; Fletcher, Evan; Carmichael, Owen; Olichney, John; Kittur, Smita; Borrie, Michael; Lee, T-Y; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M; Potkin, Steven G; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W; Kataki, Maria; Zimmerman, Earl A; Celmins, Dzintra; Brown, Alice D; Pearlson, Godfrey D; Blank, Karen; Anderson, Karen; Santulli, Robert B; Schwartz, Eben S; Sink, Kaycee M; Williamson, Jeff D; Garg, Pradeep; Watkins, Franklin; Ott, Brian R; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J; Miller, Bruce L; Mintzer, Jacobo; Longmire, Crystal Flynn; Spicer, Kenneth; Finger, Elizabether; Rachinsky, Irina; Drost, Dick; Jernigan, Terry; McCabe, Connor; Grant, Ellen; Ernst, Thomas; Kuperman, Josh; Chung, Yoon; Murray, Sarah; Bloss, Cinnamon; Darst, Burcu; Pritchett, Lexi; Saito, Ashley; Amaral, David; DiNino, Mishaela; Eyngorina, Bella; Sowell, Elizabeth; Houston, Suzanne; Soderberg, Lindsay; Kaufmann, Walter; van Zijl, Peter; Rizzo-Busack, Hilda; Javid, Mohsin; Mehta, Natasha; Ruberry, Erika; Powers, Alisa; Rosen, Bruce; Gebhard, Nitzah; Manigan, Holly; Frazier, Jean; Kennedy, David; Yakutis, Lauren; Hill, Michael; Gruen, Jeffrey; Bosson-Heenan, Joan; Carlson, Heatherly

2012-03-06

Visual cortical surface area varies two- to threefold between human individuals, is highly heritable, and has been correlated with visual acuity and visual perception. However, it is still largely unknown what specific genetic and environmental factors contribute to normal variation in the area of visual cortex. To identify SNPs associated with the proportional surface area of visual cortex, we performed a genome-wide association study followed by replication in two independent cohorts. We identified one SNP (rs6116869) that replicated in both cohorts and had genome-wide significant association (P(combined) = 3.2 × 10(-8)). Furthermore, a metaanalysis of imputed SNPs in this genomic region identified a more significantly associated SNP (rs238295; P = 6.5 × 10(-9)) that was in strong linkage disequilibrium with rs6116869. These SNPs are located within 4 kb of the 5' UTR of GPCPD1, glycerophosphocholine phosphodiesterase GDE1 homolog (Saccharomyces cerevisiae), which in humans, is more highly expressed in occipital cortex compared with the remainder of cortex than 99.9% of genes genome-wide. Based on these findings, we conclude that this common genetic variation contributes to the proportional area of human visual cortex. We suggest that identifying genes that contribute to normal cortical architecture provides a first step to understanding genetic mechanisms that underlie visual perception.

Fundamental mechanisms in premixed flame propagation via vortex-flame interactions: Numerical simulations

NASA Technical Reports Server (NTRS)

Mantel, Thierry

1994-01-01

The goal of the present study is to assess numerically the ability of single-step and two-step chemical models to describe the main features encountered during the interaction between a two-dimensional vortex pair and a premixed laminar flame. In the two-step mechanism, the reaction kinetics are represented by a first chain branching reaction A + X yields 2X and a second chain termination reaction X + X yields P. This paper presents the fundamental mechanisms occurring during vortex-flame interactions and the relative impact of the major parameters encountered in turbulent premixed flames and suspected of playing a role in quenching mechanism: (1) Influence of stretch is investigated by analyzing the contribution of curvature and tangential strain on the local structure of the flame. The effect of Lewis number on the flame response to a strained field is analyzed. (2) Radiative heat losses which are suspected to be partially or totally responsible for quenching are also investigated. (3) The effect of the diffusion of the radicals is studied using a two-step mechanism in which an intermediate species is present. The parameters of the two-step mechanism are entirely determined from physical arguments. (4) Precise quantitative comparisons between the DNS and the experimental results of Samaniego et al are performed. These comparisons concern the evolution of the minimum heat release rate found along the flame front during the interaction and the distribution of the heat release rate along the flame front.

Quantum Authencryption with Two-Photon Entangled States for Off-Line Communicants

NASA Astrophysics Data System (ADS)

Ye, Tian-Yu

2016-02-01

In this paper, a quantum authencryption protocol is proposed by using the two-photon entangled states as the quantum resource. Two communicants Alice and Bob share two private keys in advance, which determine the generation of two-photon entangled states. The sender Alice sends the two-photon entangled state sequence encoded with her classical bits to the receiver Bob in the manner of one-step quantum transmission. Upon receiving the encoded quantum state sequence, Bob decodes out Alice's classical bits with the two-photon joint measurements and authenticates the integrity of Alice's secret with the help of one-way hash function. The proposed protocol only uses the one-step quantum transmission and needs neither a public discussion nor a trusted third party. As a result, the proposed protocol can be adapted to the case where the receiver is off-line, such as the quantum E-mail systems. Moreover, the proposed protocol provides the message authentication to one bit level with the help of one-way hash function and has an information-theoretical efficiency equal to 100 %.

Kinetic Analysis of DNA Strand Joining by Chlorella Virus DNA Ligase and the Role of Nucleotidyltransferase Motif VI in Ligase Adenylylation*

PubMed Central

Samai, Poulami; Shuman, Stewart

2012-01-01

Chlorella virus DNA ligase (ChVLig) is an instructive model for mechanistic studies of the ATP-dependent DNA ligase family. ChVLig seals 3′-OH and 5′-PO4 termini via three chemical steps: 1) ligase attacks the ATP α phosphorus to release PPi and form a covalent ligase-adenylate intermediate; 2) AMP is transferred to the nick 5′-phosphate to form DNA-adenylate; 3) the 3′-OH of the nick attacks DNA-adenylate to join the polynucleotides and release AMP. Each chemical step requires Mg2+. Kinetic analysis of nick sealing by ChVLig-AMP revealed that the rate constant for phosphodiester synthesis (kstep3 = 25 s−1) exceeds that for DNA adenylylation (kstep2 = 2.4 s−1) and that Mg2+ binds with similar affinity during step 2 (Kd = 0.77 mm) and step 3 (Kd = 0.87 mm). The rates of DNA adenylylation and phosphodiester synthesis respond differently to pH, such that step 3 becomes rate-limiting at pH ≤ 6.5. The pH profiles suggest involvement of one and two protonation-sensitive functional groups in catalysis of steps 2 and 3, respectively. We suggest that the 5′-phosphate of the nick is the relevant protonation-sensitive moiety and that a dianionic 5′-phosphate is necessary for productive step 2 catalysis. Motif VI, located at the C terminus of the OB-fold domain of ChVLig, is a conserved feature of ATP-dependent DNA ligases and GTP-dependent mRNA capping enzymes. Presteady state and burst kinetic analysis of the effects of deletion and missense mutations highlight the catalytic contributions of ChVLig motif VI, especially the Asp-297 carboxylate, exclusively during the ligase adenylylation step. PMID:22745124

The impact of a public health department's expansion from a one-step to a two-step refugee screening process on the detection and initiation of treatment of latent tuberculosis.

PubMed

Einterz, E M; Younge, O; Hadi, C

2018-06-01

To determine, subsequent to the expansion of a county health department's refugee screening process from a one-step to a two-step process, the change in early loss to follow-up and time to initiation of treatment of new refugees with latent tuberculosis infection (LTBI). Quasi-experimental, quantitative. Review of patient medical records. Among 384 refugees who met the case definition of LTBI without prior tuberculosis (TB) classification, the number of cases lost to early follow-up fell from 12.5% to 0% after expansion to a two-step screening process. The average interval between in-country arrival and initiation of LTBI treatment was shortened by 41.4%. The addition of a second step to the refugee screening process was correlated with significant improvements in the county's success in tracking and treating cases of LTBI in refugees. Given the disproportionate importance of foreign-born cases of LTBI to the incidence of TB disease in low-incidence countries, these improvements could have a substantial impact on overall TB control, and the process described could serve as a model for other local health department refugee screening programs. Copyright © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

MO-DE-207A-10: One-Step CT Reconstruction for Metal Artifact Reduction by a Modification of Penalized Weighted Least-Squares (PWLS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, H; Chen, J

Purpose: Metal objects create severe artifacts in kilo-voltage (kV) CT image reconstructions due to the high attenuation coefficients of high atomic number objects. Most of the techniques devised to reduce this artifact utilize a two-step approach, which do not reliably yield the qualified reconstructed images. Thus, for accuracy and simplicity, this work presents a one-step reconstruction method based on a modified penalized weighted least-squares (PWLS) technique. Methods: Existing techniques for metal artifact reduction mostly adopt a two-step approach, which conduct additional reconstruction with the modified projection data from the initial reconstruction. This procedure does not consistently perform well due tomore » the uncertainties in manipulating the metal-contaminated projection data by thresholding and linear interpolation. This study proposes a one-step reconstruction process using a new PWLS operation with total-variation (TV) minimization, while not manipulating the projection. The PWLS for CT reconstruction has been investigated using a pre-defined weight, based on the variance of the projection datum at each detector bin. It works well when reconstructing CT images from metal-free projection data, which does not appropriately penalize metal-contaminated projection data. The proposed work defines the weight at each projection element under the assumption of a Poisson random variable. This small modification using element-wise penalization has a large impact in reducing metal artifacts. For evaluation, the proposed technique was assessed with two noisy, metal-contaminated digital phantoms, against the existing PWLS with TV minimization and the two-step approach. Result: The proposed PWLS with TV minimization greatly improved the metal artifact reduction, relative to the other techniques, by watching the results. Numerically, the new approach lowered the normalized root-mean-square error about 30 and 60% for the two cases, respectively, compared to the two-step method. Conclusion: A new PWLS operation shows promise for improving metal artifact reduction in CT imaging, as well as simplifying the reconstructing procedure.« less

The effect of different screw-tightening techniques on the stress generated on an internal-connection implant superstructure.

PubMed

Choi, Jung-Han; Lim, Young-Jun; Kim, Chang-Whe; Kim, Myung-Joo

2009-01-01

This study evaluated the effect of different screw-tightening sequences, forces, and methods on the stresses generated on a well-fitting internal-connection implant (Astra Tech) superstructure. A metal framework directly connected to four parallel implants was fabricated on a fully edentulous mandibular resin model. Six stone casts with four implant replicas were made from a pickup impression of the superstructure to represent a "well-fitting" situation. Stresses generated by four screw-tightening sequences (1-2-3-4, 4-3-2-1, 2-4-3-1, and 2-3-1-4), two forces (10 and 20 Ncm), and two methods (one-step and two-step) were evaluated. In the two-step method, screws were tightened to the initial torque (10 Ncm) in a predetermined screw-tightening sequence and then to the final torque (20 Ncm) in the same sequence. Stresses were recorded twice by three strain gauges attached to the framework (superior face midway between abutments). Deformation data were analyzed using multiple analysis of variance at a .05 level of statistical significance. In all stone casts, stresses were produced by the superstructure connection, regardless of screw-tightening sequence, force, and method. No statistically significant differences for superstructure preload stresses were found based on screw-tightening sequences (-180.0 to -181.6 microm/m) or forces (-163.4 and -169.2 microm/m) (P > .05). However, different screw-tightening methods induced different stresses on the superstructure. The two-step screw-tightening method (-180.1 microm/m) produced significantly higher stress than the one-step method (-169.2 microm/m) (P = .0457). Within the limitations of this in vitro study, screw-tightening sequence and force were not critical factors in the stress generated on a well-fitting internal-connection implant superstructure. The stress caused by the two-step method was greater than that produced using the one-step method. Further studies are needed to evaluate the effect of screw-tightening techniques on preload stress in various different clinical situations.

Project-Based Learning Courses: The Relationship Between Faculty-Intended Course Implementation and Students' Perceptions

NASA Astrophysics Data System (ADS)

Simonovich, Jennifer A.; Towers, Emily; Zastavker, Yevgeniya V.

2012-02-01

Project-based learning (PjBL) has been shown to improve students' performance and satisfaction with their coursework, particularly in science and engineering courses. Specific aspects of PjBL that contribute to this improvement are student autonomy, course scaffolding, and instructor support. This study investigates two PjBL courses required for engineering majors at a small technical school, Introductory Mechanics Laboratory and Introductory Engineering Design. The three data sources used in this work are classroom observations (one laboratory and four design sessions) and semi-structured in-depth interviews with twelve students and six faculty. Grounded theory approach is used in a two-step fashion by (1) analyzing each data set individually and (2) performing full triangulation of all three data sets. In this talk, we demonstrate the relationship between faculty intentions and student perceptions regarding the three PjBL aspects -- student autonomy, course scaffolding, and instructor support -- within the context of these two courses. We further discuss implications for the course design and professional development of faculty.

Assessing the foundation of the Trojan Horse Method

NASA Astrophysics Data System (ADS)

Bertulani, C. A.; Hussein, M. S.; Typel, S.

2018-01-01

We discuss the foundation of the Trojan Horse Method (THM) within the Inclusive Non-Elastic Breakup (INEB) theory. We demonstrate that the direct part of the INEB cross section, which is of two-step character, becomes, in the DWBA limit of the three-body theory with appropriate approximations and redefinitions, similar in structure to the one-step THM cross section. We also discuss the connection of the THM to the Surrogate Method (SM), which is a genuine two-step process.

N-terminus of Cardiac Myosin Essential Light Chain Modulates Myosin Step-Size

PubMed Central

Wang, Yihua; Ajtai, Katalin; Kazmierczak, Katarzyna; Szczesna-Cordary, Danuta; Burghardt, Thomas P.

2016-01-01

Muscle myosin cyclically hydrolyzes ATP to translate actin. Ventricular cardiac myosin (βmys) moves actin with three distinct unitary step-sizes resulting from its lever-arm rotation and with step-frequencies that are modulated in a myosin regulation mechanism. The lever-arm associated essential light chain (vELC) binds actin by its 43 residue N-terminal extension. Unitary steps were proposed to involve the vELC N-terminal extension with the 8 nm step engaging the vELC/actin bond facilitating an extra ~19 degrees of lever-arm rotation while the predominant 5 nm step forgoes vELC/actin binding. A minor 3 nm step is the unlikely conversion of the completed 5 to the 8 nm step. This hypothesis was tested using a 17 residue N-terminal truncated vELC in porcine βmys (Δ17βmys) and a 43 residue N-terminal truncated human vELC expressed in transgenic mouse heart (Δ43αmys). Step-size and step-frequency were measured using the Qdot motility assay. Both Δ17βmys and Δ43αmys had significantly increased 5 nm step-frequency and coincident loss in the 8 nm step-frequency compared to native proteins suggesting the vELC/actin interaction drives step-size preference. Step-size and step-frequency probability densities depend on the relative fraction of truncated vELC and relate linearly to pure myosin species concentrations in a mixture containing native vELC homodimer, two truncated vELCs in the modified homodimer, and one native and one truncated vELC in the heterodimer. Step-size and step-frequency, measured for native homodimer and at two or more known relative fractions of truncated vELC, are surmised for each pure species by using a new analytical method. PMID:26671638

Multienzymatic cascade synthesis of fucosyloligosaccharide via a two-step fermentation strategy in Escherichia coli.

PubMed

Qin, Hui-Min; Li, Songtao; Zhang, Yu-Fu; Wang, Jian-Wen; Li, Jixuan; Song, Shiyi; Lu, Fuping; Li, Yu

2016-10-01

To achieve multienzymatic cascade synthesis of fucosyl oligosaccharide from D-mannose by two-step fermentation pathway in Escherichia coli. E. coli BL21(DE3) harboring pET-22b(+) vectors with six genes, i.e., glucokinase (Glk), phosphomannomutase (ManB), mannose-1-phosphate guanylytransferase (ManC), GDP-mannose 4,6-dehydratase (Gmd), GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase/4-reductase (WcaG), and α-1,2-fucosyltransferase (Fuct) were co-inoculated, and the multienzyme synthetic pathway was constructed to produce fucosyloligosaccharide using D-mannose as substrate. The product, analyzed by LC/MS, fucosyloligosaccharide was formed under the catalysis of Fuct using GDP-fucose as donor substrate and lactose as acceptor substrate. Fucosyloligosaccharides reached 22 mM by a two-step fermentation compared to 3.7 mM with a one-pot fermentation. Fucosyloligosaccharide was produced by a two-step fermentation to avoid the inhibitory effect of GDP-fucose on Gmd. Two-step fermentation is a rational synthetic pathway for accumulating fucosyloligosaccharide.

Learning to detect and combine the features of an object

PubMed Central

Suchow, Jordan W.; Pelli, Denis G.

2013-01-01

To recognize an object, it is widely supposed that we first detect and then combine its features. Familiar objects are recognized effortlessly, but unfamiliar objects—like new faces or foreign-language letters—are hard to distinguish and must be learned through practice. Here, we describe a method that separates detection and combination and reveals how each improves as the observer learns. We dissociate the steps by two independent manipulations: For each step, we do or do not provide a bionic crutch that performs it optimally. Thus, the two steps may be performed solely by the human, solely by the crutches, or cooperatively, when the human takes one step and a crutch takes the other. The crutches reveal a double dissociation between detecting and combining. Relative to the two-step ideal, the human observer’s overall efficiency for unconstrained identification equals the product of the efficiencies with which the human performs the steps separately. The two-step strategy is inefficient: Constraining the ideal to take two steps roughly halves its identification efficiency. In contrast, we find that humans constrained to take two steps perform just as well as when unconstrained, which suggests that they normally take two steps. Measuring threshold contrast (the faintness of a barely identifiable letter) as it improves with practice, we find that detection is inefficient and learned slowly. Combining is learned at a rate that is 4× higher and, after 1,000 trials, 7× more efficient. This difference explains much of the diversity of rates reported in perceptual learning studies, including effects of complexity and familiarity. PMID:23267067

Isothermal Amplification Methods for the Detection of Nucleic Acids in Microfluidic Devices

PubMed Central

Zanoli, Laura Maria; Spoto, Giuseppe

2012-01-01

Diagnostic tools for biomolecular detection need to fulfill specific requirements in terms of sensitivity, selectivity and high-throughput in order to widen their applicability and to minimize the cost of the assay. The nucleic acid amplification is a key step in DNA detection assays. It contributes to improving the assay sensitivity by enabling the detection of a limited number of target molecules. The use of microfluidic devices to miniaturize amplification protocols reduces the required sample volume and the analysis times and offers new possibilities for the process automation and integration in one single device. The vast majority of miniaturized systems for nucleic acid analysis exploit the polymerase chain reaction (PCR) amplification method, which requires repeated cycles of three or two temperature-dependent steps during the amplification of the nucleic acid target sequence. In contrast, low temperature isothermal amplification methods have no need for thermal cycling thus requiring simplified microfluidic device features. Here, the use of miniaturized analysis systems using isothermal amplification reactions for the nucleic acid amplification will be discussed. PMID:25587397

Telemedicine for epilepsy support in resource-poor settings.

PubMed

Patterson, Victor

2014-01-01

Epilepsy is a common disease worldwide causing significant physical and social disability. It is one of the most treatable neurological diseases. Yet, in rural, poorer countries like much of India and Nepal, most people with epilepsy are not undergoing any treatment often because they cannot access doctors. Conventional Approaches: It is being appreciated that perhaps doctors are not the solution and that enabling health workers to treat epilepsy may be better. Few details, however, have been put forward about how that might be achieved. Thinking Differently: Untreated epilepsy should be considered a public health problem like HIV/AIDS, the various steps needed for treatment identified and solutions found. Telemedicine Approaches: Telemedicine might contribute to two steps - diagnosis and review. A tool that enables non-doctors to diagnose episodes as epileptic has been developed as a mobile phone app and has good applicability, sensitivity, and specificity for the diagnosis. There are a number of ways in which the use of phone review or short messaging service can improve management. Telemedicine, as part of a public health program, can potentially help the millions of people in the resource-poor world with untreated epilepsy.

Embryonic ring closure: Actomyosin rings do the two-step

PubMed Central

2016-01-01

Actomyosin rings drive numerous closure processes, but the mechanisms by which they contract are still poorly understood. In this issue, Xue and Sokac (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201608025) show that actomyosin ring closure during Drosophila melanogaster cellularization uses two steps, only one of which involves Myosin-2. PMID:27799371

Saddlepoint approximation to the distribution of the total distance of the continuous time random walk

NASA Astrophysics Data System (ADS)

Gatto, Riccardo

2017-12-01

This article considers the random walk over Rp, with p ≥ 2, where a given particle starts at the origin and moves stepwise with uniformly distributed step directions and step lengths following a common distribution. Step directions and step lengths are independent. The case where the number of steps of the particle is fixed and the more general case where it follows an independent continuous time inhomogeneous counting process are considered. Saddlepoint approximations to the distribution of the distance from the position of the particle to the origin are provided. Despite the p-dimensional nature of the random walk, the computations of the saddlepoint approximations are one-dimensional and thus simple. Explicit formulae are derived with dimension p = 3: for uniformly and exponentially distributed step lengths, for fixed and for Poisson distributed number of steps. In these situations, the high accuracy of the saddlepoint approximations is illustrated by numerical comparisons with Monte Carlo simulation. Contribution to the "Topical Issue: Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

DOEpatents

Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

2010-04-13

A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

Ranking and validation of the spallation models for description of intermediate mass fragment emission from p + Ag collisions at 480 MeV incident proton beam energy

NASA Astrophysics Data System (ADS)

Sharma, Sushil K.; Kamys, Bogusław; Goldenbaum, Frank; Filges, Detlef

2016-06-01

Double-differential cross-sections d2σ/dΩ dE for isotopically identified intermediate mass fragments ( 6Li up to 27Mg from nuclear reactions induced by 480 MeV protons impinging on a silver target were analyzed in the frame of a two-step model. The first step of the reaction was described by the intranuclear cascade model INCL4.6 and the second one by four different models (ABLA07,GEM2, GEMINI++, and SMM). The experimental spectra reveal the presence of low-energy, isotropic as well as high-energy, forward-peaked contributions. The INCL4.6 model offers a possibility to describe the latter contribution for light intermediate mass fragments by coalescence of the emitted nucleons. The qualitative agreement of the model predictions with the data was observed but the high-energy tails of the spectra were significantly overestimated. The shape of the isotropic part of the spectra was reproduced by all four models. The GEM2 model strongly underestimated the value of the cross-sections for heavier IMF whereas the SMM and ABLA07 models generally overestimated the data. The best quantitative description of the data was offered by GEMINI++, however, a discrepancy between the data and the model cross-sections still remained for almost all reaction products, especially at forward angles. It indicates that non-equilibrium processes are present which cannot be reproduced by the applied models. The goodness of the data description was judged quantitatively using two statistical deviation factors, the H-factor and the M-factor, as a tool for ranking and validation of the theoretical models.

Recoded and nonrecoded trinary signed-digit adders and multipliers with redundant-bit representations

NASA Astrophysics Data System (ADS)

Cherri, Abdallah K.; Alam, Mohammed S.

1998-07-01

Highly-efficient two-step recoded and one-step nonrecoded trinary signed-digit (TSD) carry-free adders subtracters are presented on the basis of redundant-bit representation for the operands digits. It has been shown that only 24 (30) minterms are needed to implement the two-step recoded (the one-step nonrecoded) TSD addition for any operand length. Optical implementation of the proposed arithmetic can be carried out by use of correlation- or matrix-multiplication-based schemes, saving 50% of the system memory. Furthermore, we present four different multiplication designs based on our proposed recoded and nonrecoded TSD adders. Our multiplication designs require a small number of reduced minterms to generate the multiplication partial products. Finally, a recently proposed pipelined iterative-tree algorithm can be used in the TSD adders multipliers; consequently, efficient use of all available adders can be made.

Recoded and nonrecoded trinary signed-digit adders and multipliers with redundant-bit representations.

PubMed

Cherri, A K; Alam, M S

1998-07-10

Highly-efficient two-step recoded and one-step nonrecoded trinary signed-digit (TSD) carry-free adders-subtracters are presented on the basis of redundant-bit representation for the operands' digits. It has been shown that only 24 (30) minterms are needed to implement the two-step recoded (the one-step nonrecoded) TSD addition for any operand length. Optical implementation of the proposed arithmetic can be carried out by use of correlation- or matrix-multiplication-based schemes, saving 50% of the system memory. Furthermore, we present four different multiplication designs based on our proposed recoded and nonrecoded TSD adders. Our multiplication designs require a small number of reduced minterms to generate the multiplication partial products. Finally, a recently proposed pipelined iterative-tree algorithm can be used in the TSD adders-multipliers; consequently, efficient use of all available adders can be made.

Interobserver Agreement in Clinical Grading of Vitreous Haze Using Alternative Grading Scales

PubMed Central

Hornbeak, Dana M; Payal, Abhishek; Pistilli, Maxwell; Biswas, Jyotirmay; Ganesh, Sudha K; Gupta, Vishali; Rathinam, Sivakumar R; Davis, Janet L; Kempen, John H

2014-01-01

Purpose To evaluate the reliability of clinical grading of vitreous haze using a new 9-step ordinal scale vs. the existing 6-step ordinal scale. Design Evaluation of Diagnostic Test (interobserver agreement study). Participants 119 consecutive patients (204 uveitic eyes) presenting for uveitis subspecialty care on the study day at one of three large uveitis centers. Methods Five pairs of uveitis specialists clinically graded vitreous haze in the same eyes, one after the other using the same equipment, using the 6- and 9-step scales. Main Outcome Measures Agreement in vitreous haze grade between each pair of specialists was evaluated by the κ statistic (exact agreement and agreement within one or two grades). Results The scales correlated well (Spearman’s ρ=0.84). Exact agreement was modest using both the 6-step and 9-step scales: average κ=0.46 (range 0.28–0.81) and κ=0.40 (range 0.15–0.63), respectively. Within-1-grade agreement was slightly more favorable for the scale with fewer steps, but values were excellent for both scales: κ=0.75 (range 0.66–0.96) and κ=0.62 (range 0.38–0.87), respectively. Within-2-grade agreement for the 9-step scale also was excellent [κ=0.85 (range 0.79–0.92)]. Two-fold more cases were potentially clinical trial eligible based on the 9- than the 6-step scale (p<0.001). Conclusions Both scales are sufficiently reproducible using clinical grading for clinical and research use with the appropriate threshold (a ≥2 and ≥3 step differences for the 6-step and 9-step scales respectively). The results suggest that more eyes are likely to meet eligibility criteria for trials using the 9-step scale. The 9-step scale appears to have higher reproducibility with Reading Center grading than clinical grading, suggesting Reading Center grading may be preferable for clinical trials. PMID:24697913

Molecular Dynamics of Flexible Polar Cations in a Variable Confined Space: Toward Exceptional Two-Step Nonlinear Optical Switches.

PubMed

Xu, Wei-Jian; He, Chun-Ting; Ji, Cheng-Min; Chen, Shao-Li; Huang, Rui-Kang; Lin, Rui-Biao; Xue, Wei; Luo, Jun-Hua; Zhang, Wei-Xiong; Chen, Xiao-Ming

2016-07-01

The changeable molecular dynamics of flexible polar cations in the variable confined space between inorganic chains brings about a new type of two-step nonlinear optical (NLO) switch with genuine "off-on-off" second harmonic generation (SHG) conversion between one NLO-active state and two NLO-inactive states. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy release, beam attenuation radiation damage, gas production and accumulation of long-lived activity in Pb, Pb-Bi and Hg targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shubin, Yu.N.

1996-06-01

The calculation and analysis of the nuclei concentrations and long-lived residual radioactivity accumulated in Pb, Pb-Bi and Hg targets irradiated by 800 MeV, 30 mA proton beam have been performed. The dominating components to the total radioactivity of radionuclides resulting from fission and spallation reactions and radiative capture by both target nuclei and accumulated radioactive nuclei for various irradiation and cooling times were analyzed. The estimations of spectral component contributions of neutron and proton fluxes to the accumulated activity were carried out. The contributions of fission products to the targets activity and partial activities of main long-lived fission products tomore » the targets activity and partial activities of main long-lived fission products were evaluated. The accumulation of Po isotopes due to reactions induced by secondary alpha-particles were found to be important for the Pb target as compared with two-step radiative capture. The production of Tritium in the targets and its contribution to the total targets activity was considered in detail. It is found that total activities of both targets are close to one another.« less

Grandparenting and adolescent adjustment in two-parent biological, lone-parent, and step-families.

PubMed

Attar-Schwartz, Shalhevet; Tan, Jo-Pei; Buchanan, Ann; Flouri, Eirini; Griggs, Julia

2009-02-01

There is limited research on the links between grandparenting and adolescents' well-being, especially from the perspective of the adolescents. The study examined whether grandparent involvement varied in two-parent biological, lone-parent, and step-families and whether this had a different contribution to the emotional and behavioral adjustment of adolescents across different family structures. The study is based on a sample of 1,515 secondary school students (ages 11-16 years) from England and Wales who completed a structured questionnaire. Findings of hierarchical regression analyses showed that among the whole sample, greater grandparent involvement was associated with fewer emotional problems (p < .01) and with more prosocial behavior (p < .001). In addition, while there were no differences in the level of grandparent involvement across the different family structures, grandparent involvement was more strongly associated with reduced adjustment difficulties among adolescents from lone-parent and step-families than those from two-parent biological families. A possible implication is that the positive role of grandparent involvement in lone-parent and step- families should be more emphasized in family psychology. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

"Reluctant Participants" in Role Play Simulations: Stage Fright or Bewilderment?

ERIC Educational Resources Information Center

Saunders, Danny

1985-01-01

Discusses factors contributing to participant reluctance in role playing--isolation of role play from the curriculum; lack of interest because of perceived irrelevance to social psychological themes; and acting anxiety. A two-step design which involves gradual role play introduction and observation by reluctant participants is suggested as a…

PETOOL: MATLAB-based one-way and two-way split-step parabolic equation tool for radiowave propagation over variable terrain

NASA Astrophysics Data System (ADS)

Ozgun, Ozlem; Apaydin, Gökhan; Kuzuoglu, Mustafa; Sevgi, Levent

2011-12-01

A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation over variable terrain and through homogeneous and inhomogeneous atmosphere. The tool has a unique feature over existing one-way parabolic equation (PE)-based codes, because it utilizes the two-way split-step parabolic equation (SSPE) approach with wide-angle propagator, which is a recursive forward-backward algorithm to incorporate both forward and backward waves into the solution in the presence of variable terrain. First, the formulation of the classical one-way SSPE and the relatively-novel two-way SSPE is presented, with particular emphasis on their capabilities and the limitations. Next, the structure and the GUI capabilities of the PETOOL software tool are discussed in detail. The calibration of PETOOL is performed and demonstrated via analytical comparisons and/or representative canonical tests performed against the Geometric Optic (GO) + Uniform Theory of Diffraction (UTD). The tool can be used for research and/or educational purposes to investigate the effects of a variety of user-defined terrain and range-dependent refractivity profiles in electromagnetic wave propagation. Program summaryProgram title: PETOOL (Parabolic Equation Toolbox) Catalogue identifier: AEJS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJS_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 143 349 No. of bytes in distributed program, including test data, etc.: 23 280 251 Distribution format: tar.gz Programming language: MATLAB (MathWorks Inc.) 2010a. Partial Differential Toolbox and Curve Fitting Toolbox required Computer: PC Operating system: Windows XP and Vista Classification: 10 Nature of problem: Simulation of radio-wave propagation over variable terrain on the Earth's surface, and through homogeneous and inhomogeneous atmosphere. Solution method: The program implements one-way and two-way Split-Step Parabolic Equation (SSPE) algorithm, with wide-angle propagator. The SSPE is, in general, an initial-value problem starting from a reference range (typically from an antenna), and marching out in range by obtaining the field along the vertical direction at each range step, through the use of step-by-step Fourier transformations. The two-way algorithm incorporates the backward-propagating waves into the standard one-way SSPE by utilizing an iterative forward-backward scheme for modeling multipath effects over a staircase-approximated terrain. Unusual features: This is the first software package implementing a recursive forward-backward SSPE algorithm to account for the multipath effects during radio-wave propagation, and enabling the user to easily analyze and visualize the results of the two-way propagation with GUI capabilities. Running time: Problem dependent. Typically, it is about 1.5 ms (for conducting ground) and 4 ms (for lossy ground) per range step for a vertical field profile of vector length 1500, on Intel Core 2 Duo 1.6 GHz with 2 GB RAM under Windows Vista.

Coffee intake.

PubMed

Cornelis, Marilyn C

2012-01-01

Coffee is one of the most widely consumed beverages in the world. Its widespread popularity and availability has fostered public health concerns of the potential health consequences of regular coffee consumption. Epidemiological studies of coffee intake and certain health outcomes have been inconsistent. The precise component of coffee potentially contributing to development of these conditions also remains unclear. One step toward addressing the challenges in studying the impact coffee has on health is a better understanding of the factors contributing to its consumption and physiological effects. This chapter focuses on those factors that are genetically determined and briefly summarizes progress in applying this knowledge to epidemiological studies of coffee and disease. Copyright © 2012 Elsevier Inc. All rights reserved.

Frequency Analysis of the Laser Biospeckle

NASA Astrophysics Data System (ADS)

Enes, Adilson M.; Rabelo, Giovanni F.; Júnior, Roberto A. Braga; Dal Fabbro, Inácio M.; Vilela, Michelle

2008-04-01

This research work presents a study of beans seed tissue (Phaseolous vulgaris, L.) optical interactions with laser aiming to contribute to the development of biospeckle techniques applied to the recognition of bean seed tissue vitality when contaminated with fungi, by differentiating the generated frequency spectra. Biospeckle is an interference optic phenomenon occurring when a laser beam reaches a surface exhibiting some dynamic process, due to biological activities or purely physical changes. The technique involves image processing to distinguish each different active material contribution present in the seed, by means of the procedure known as "Moment of Inertia" and frequency analysis. Frequency analysis was carried by Fourier Transform preceded by module of convolution. A great challenge in this area is to identify the elements contribution to increase biospeckle activity, such as water, microorganisms, among others. This research work is recognized to provide an important step aiming to characterize the interaction of laser with biological material. Three groups of bean seeds were employed, one represented by healthy seeds and two groups composed of seeds contaminated with Aspergillus spp as well as with Fusarium spp fungi. The biospeckle analysis considered the activity and its frequency spectra. The seeds were each one exposed to laser in a random order. The results reveled differences in the average values of MI of the three seed groups. Also, some different harmonics in the biospeckle pattern in a same group as well as among seed groups had been noticed. These results allow confirming that it is possible to differentiate contaminated seeds from non-contaminated ones by means of biospeckle frequency analysis.

Vitrification of zona-free rabbit expanded or hatching blastocysts: a possible model for human blastocysts.

PubMed

Cervera, R P; Garcia-Ximénez, F

2003-10-01

The purpose of this study was to test the effectiveness of one two-step (A) and two one-step (B1 and B2) vitrification procedures on denuded expanded or hatching rabbit blastocysts held in standard sealed plastic straws as a possible model for human blastocysts. The effect of blastocyst size was also studied on the basis of three size categories (I: diameter <200 micro m; II: diameter 200-299 micro m; III: diameter >/==" BORDER="0">300 micro m). Rabbit expanded or hatching blastocysts were vitrified at day 4 or 5. Before vitrification, the zona pellucida was removed using acidic phosphate buffered saline. For the two-step procedure, prior to vitrification, blastocysts were pre- equilibrated in a solution containing 10% dimethyl sulphoxide (DMSO) and 10% ethylene glycol (EG) for 1 min. Different final vitrification solutions were compared: 20% DMSO and 20% EG with (A and B1) or without (B2) 0.5 mol/l sucrose. Of 198 vitrified blastocysts, 181 (91%) survived, regardless of the vitrification procedure applied. Vitrification procedure A showed significantly higher re-expansion (88%), attachment (86%) and trophectoderm outgrowth (80%) rates than the two one-step vitrification procedures, B1 and B2 (46 and 21%, 20 and 33%, and 18 and 23%, respectively). After warming, blastocysts of greater size (II and III) showed significantly higher attachment (54 and 64%) and trophectoderm outgrowth (44 and 58%) rates than smaller blastocysts (I, attachment: 29%; trophectoderm outgrowth: 25%). These result demonstrate that denuded expanded or hatching rabbit blastocysts of greater size can be satisfactorily vitrified by use of a two-step procedure. The similarity of vitrification solutions used in humans could make it feasible to test such a procedure on human denuded blastocysts of different sizes.

Numerical calculation on a two-step subdiffusion behavior of lateral protein movement in plasma membranes

NASA Astrophysics Data System (ADS)

Sumi, Tomonari; Okumoto, Atsushi; Goto, Hitoshi; Sekino, Hideo

2017-10-01

A two-step subdiffusion behavior of lateral movement of transmembrane proteins in plasma membranes has been observed by using single-molecule experiments. A nested double-compartment model where large compartments are divided into several smaller ones has been proposed in order to explain this observation. These compartments are considered to be delimited by membrane-skeleton "fences" and membrane-protein "pickets" bound to the fences. We perform numerical simulations of a master equation using a simple two-dimensional lattice model to investigate the heterogeneous diffusion dynamics behavior of transmembrane proteins within plasma membranes. We show that the experimentally observed two-step subdiffusion process can be described using fence and picket models combined with decreased local diffusivity of transmembrane proteins in the vicinity of the pickets. This allows us to explain the two-step subdiffusion behavior without explicitly introducing nested double compartments.

Pedometer determined physical activity tracks in African American adults: the Jackson Heart Study.

PubMed

Newton, Robert L; M, Hongmei Han; Dubbert, Patricia M; Johnson, William D; Hickson, DeMarc A; Ainsworth, Barbara; Carithers, Teresa; Taylor, Herman; Wyatt, Sharon; Tudor-Locke, Catrine

2012-04-18

This study investigated the number of pedometer assessment occasions required to establish habitual physical activity in African American adults. African American adults (mean age 59.9 ± 0.60 years; 59 % female) enrolled in the Diet and Physical Activity Substudy of the Jackson Heart Study wore Yamax pedometers during 3-day monitoring periods, assessed on two to three distinct occasions, each separated by approximately one month. The stability of pedometer measured PA was described as differences in mean steps/day across time, as intraclass correlation coefficients (ICC) by sex, age, and body mass index (BMI) category, and as percent of participants changing steps/day quartiles across time. Valid data were obtained for 270 participants on either two or three different assessment occasions. Mean steps/day were not significantly different across assessment occasions (p values > 0.456). The overall ICCs for steps/day assessed on either two or three occasions were 0.57 and 0.76, respectively. In addition, 85 % (two assessment occasions) and 76 % (three assessment occasions) of all participants remained in the same steps/day quartile or changed one quartile over time. The current study shows that an overall mean steps/day estimate based on a 3-day monitoring period did not differ significantly over 4 - 6 months. The findings were robust to differences in sex, age, and BMI categories. A single 3-day monitoring period is sufficient to capture habitual physical activity in African American adults.

A rapid, one step molecular identification of Trichoderma citrinoviride and Trichoderma reesei.

PubMed

Saroj, Dina B; Dengeti, Shrinivas N; Aher, Supriya; Gupta, Anil K

2015-06-01

Trichoderma species are widely used as production hosts for industrial enzymes. Identification of Trichoderma species requires a complex molecular biology based identification involving amplification and sequencing of multiple genes. Industrial laboratories are required to run identification tests repeatedly in cell banking procedures and also to prove absence of production host in the product. Such demands can be fulfilled by a brief method which enables confirmation of strain identity. This communication describes one step identification method for two common Trichoderma species; T. citrinoviride and T. reesei, based on identification of polymorphic region in the nucleotide sequence of translation elongation factor 1 alpha. A unique forward primer and common reverse primer resulted in 153 and 139 bp amplicon for T. citrinoviride and T. reesei, respectively. Simplification was further introduced by using mycelium as template for PCR amplification. Method described in this communication allows rapid, one step identification of two Trichoderma species.

Girls' physical activity levels during organized sports in Australia.

PubMed

Guagliano, Justin M; Rosenkranz, Richard R; Kolt, Gregory S

2013-01-01

The primary aim of this study was to objectively examine the physical activity (PA) levels of girls during organized sports (OS) and to compare the levels between games and practices for the same participants. The secondary aims of this study were to document lesson context and coach behavior during practices and games. Participants were 94 girls recruited from 10 teams in three OS (netball, basketball, and soccer) from the western suburbs of Sydney. Each participant wore an ActiGraph GT3X monitor for the duration of one practice and one game. The System for Observing Fitness Instruction Time was concurrently used to document lesson context and coach behavior. Girls spent a significantly higher percentage of time in moderate-to-vigorous PA (MVPA) during practices compared with games (33.8% vs 30.6%; t = 2.94, P < 0.05). Girls spent approximately 20 min·h(-1) in MVPA during practices and approximately 18 min·h(-1) in MVPA during games. An average of 2957 and 2702 steps per hour were accumulated during practices and games, respectively. However, girls spent roughly two-thirds of their OS time in light PA or sedentary. On the basis of the System for Observing Fitness Instruction Time findings, coaches spent a large proportion of practice time in management (15.0%) and knowledge delivery (18.5%). An average of 13.0 and 15.8 occurrences per hour were observed during games and practices where coaches promoted PA. For every hour of game play or practice time, girls accumulated approximately one third of the recommended 60 min of MVPA time and approximately one quarter of the 12,000 steps that girls are recommended to accumulate daily. For this population, OS seems to make a substantial contribution to the recommended amounts of MVPA and steps for participating girls. OS alone, however, does not provide amounts of PA sufficient to meet daily recommendations for adolescent girls.

Integration of Nine Steps into One Membrane Reactor To Produce Synthesis Gases for Ammonia and Liquid Fuel.

PubMed

Li, Wenping; Zhu, Xuefeng; Chen, Shuguang; Yang, Weishen

2016-07-18

The synthesis of ammonia and liquid fuel are two important chemical processes in which most of the energy is consumed in the production of H2 /N2 and H2 /CO synthesis gases from natural gas (methane). Here, we report a membrane reactor with a mixed ionic-electronic conducting membrane, in which the nine steps for the production of the two types of synthesis gases are shortened to one step by using water, air, and methane as feeds. In the membrane reactor, there is no direct CO2 emission and no CO or H2 S present in the ammonia synthesis gas. The energy consumption for the production of the two synthesis gases can be reduced by 63 % by using this membrane reactor. This promising membrane reactor process has been successfully demonstrated by experiment. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complete nitrogen removal from municipal wastewater via partial nitrification by appropriately alternating anoxic/aerobic conditions in a continuous plug-flow step feed process.

PubMed

Ge, Shijian; Peng, Yongzhen; Qiu, Shuang; Zhu, Ao; Ren, Nanqi

2014-05-15

This study assessed the technical feasibility of removing nitrogen from municipal wastewater by partial nitrification (nitritation) in a continuous plug-flow step feed process. Nitrite in the effluent accumulated to over 81.5  ± 9.2% but disappeared with the transition of process operation from anoxic/oxic mode to the anaerobic/anoxic/oxic mode. Batch tests showed obvious ammonia oxidizing bacteria (AOB) stimulation (advanced ammonia oxidation rate) and nitrite (NOB) oxidizing bacteria inhibition (reduced nitrite oxidation rate) under transient anoxic conditions. Two main factors contributed to nitritation in this continuous plug-flow process: One was the alternating anoxic and oxic operational condition; the step feed strategy guaranteed timely denitrification in anoxic zones, allowing a reduction in energy supply (nitrite) to NOB. Fluorescence in Situ Hybridization and quantitative real-time polymerase chain reaction analysis indicated that NOB population gradually decreased to 1.0  ± 0.1% of the total bacterial population (dominant Nitrospira spp., 1.55 × 10(9) copies/L) while AOB increased approximately two-fold (7.4  ± 0.9%, 1.25 × 10(10) copies/L) during the above anoxic to anaerobic transition. Most importantly, without addition of external carbon sources, the above wastewater treatment process reached 86.0  ± 4.2% of total nitrogen (TN) removal with only 7.23 ± 2.31 mg/L of TN in the effluent, which met the discharge requirements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blending Together, Step by Step: Principal Uses Professional Learning to Combine Two School Cultures into One

ERIC Educational Resources Information Center

Martin, Linda E.; Shafer, Tracy; Kragler, Sherry

2009-01-01

There is no denying that combining two schools, or even opening a new school, is loaded with challenges and frustrations as well as high expectations. Principal Tracy Shafer saw a rural school consolidation as an opportunity to use professional development to create a community focused on student learning, meeting the need for high-quality…

One Step Quantum Key Distribution Based on EPR Entanglement.

PubMed

Li, Jian; Li, Na; Li, Lei-Lei; Wang, Tao

2016-06-30

A novel quantum key distribution protocol is presented, based on entanglement and dense coding and allowing asymptotically secure key distribution. Considering the storage time limit of quantum bits, a grouping quantum key distribution protocol is proposed, which overcomes the vulnerability of first protocol and improves the maneuverability. Moreover, a security analysis is given and a simple type of eavesdropper's attack would introduce at least an error rate of 46.875%. Compared with the "Ping-pong" protocol involving two steps, the proposed protocol does not need to store the qubit and only involves one step.

Crossover assessment of cardiolocomotor synchronization during running.

PubMed

Cerqueira, Lucenildo Silva; D'Affonsêca Netto, Aluizio; Mello, Roger Gomes Tavares; Nadal, Jurandir

2017-02-01

This study aimed at testing the hypothesis that positive cardiolocomotor coordination (CLC) measure occurs by chance during a running task where the heart rate (HR) is approximated to the step frequency (StepF). The electrocardiogram and electromyogram from the right gastrocnemius lateralis muscle were continuously recorded from ten healthy young men running at a paced rhythm of 152 step/min, to monitor HR and StepF. CLC was evaluated by phase synchrograms and the index of conditional probability (iCP). Results were validated with surrogate data and a crossover approach, where the HR of one subject was related to the StepF of another one, and comparisons were made combining subjects two by two. Six subjects showed synchrogram structures and high iCP values (≥0.8), suggesting the occurrence of physiological entrainment, when the HR reached the SF range. In crossover analysis, phase synchrograms and iCP presented similar behavior of original data when the HR from one subject was close enough to the SF from another one. Significant iCP values in 46 of 90 comparisons (51%) were observed, including all cases crossing signals among the six positive cases. Synchrogram and iCP tools currently employed for measuring CLC are not appropriate because they indicate the occurrence of this phenomenon even among subjects who ran on different days and times of each other.

Spectrum online-tunable Mach-Zehnder interferometer based on step-like tapers and its refractive index sensing characteristics

NASA Astrophysics Data System (ADS)

Zhao, Yong; Chen, Mao-qing; Xia, Feng; Hu, Hai-feng

2017-11-01

A novel refractive index (RI) sensor based on an asymmetrical Mach-Zehnder interferometer (MZI) with two different step-like tapers is proposed. The step-like taper is fabricated by fusion splicing two half tapers with an appropriate offset. By further applying offset and discharging to the last fabricated step-like taper of MZI, influence of taper parameters on interference spectrum is investigated using only one device. This simple technique provides an on-line method to sweep parameters of step-like tapers and speeds up the optimization process of interference spectrum, meanwhile. In RI sensing experiment, the sensor has a high sensitivity of -185.79 nm/RIU (refractive index unit) in the RI range of 1.3333-1.3673.

Incremental value of Veterans Specific Activity Questionnaire and the YMCA-step test for the assessment of cardiorespiratory fitness in population-based studies.

PubMed

Teren, Andrej; Zachariae, Silke; Beutner, Frank; Ubrich, Romy; Sandri, Marcus; Engel, Christoph; Löffler, Markus; Gielen, Stephan

2016-07-01

Cardiorespiratory fitness is a well-established independent predictor of cardiovascular health. However, the relevance of alternative exercise and non-exercise tests for cardiorespiratory fitness assessment in large cohorts has not been studied in detail. We aimed to evaluate the YMCA-step test and the Veterans Specific Activity Questionnaire (VSAQ) for the estimation of cardiorespiratory fitness in the general population. One hundred and five subjects answered the VSAQ, performed the YMCA-step test and a maximal cardiopulmonary exercise test (CPX) and gave BORG ratings for both exercise tests (BORGSTEP, BORGCPX). Correlations of peak oxygen uptake on a treadmill (VO2_PEAK) with VSAQ, BORGSTEP, one-minute, post-exercise heartbeat count, and peak oxygen uptake during the step test (VO2_STEP) were determined. Moreover, the incremental values of the questionnaire and the step test in addition to other fitness-related parameters were evaluated using block-wise hierarchical regression analysis. Eighty-six subjects completed the step test according to the protocol. For completers, correlations of VO2_PEAK with the age- and gender-adjusted VSAQ, heartbeat count and VO2_STEP were 0.67, 0.63 and 0.49, respectively. However, using hierarchical regression analysis, age, gender and body mass index already explained 68.8% of the variance of VO2_PEAK, while the additional benefit of VSAQ was rather low (3.4%). The inclusion of BORGSTEP, heartbeat count and VO2_STEP increased R(2) by a further 2.2%, 3.3% and 5.6%, respectively, yielding a total R(2) of 83.3%. Neither VSAQ nor the YMCA-step test contributes sufficiently to the assessment of cardiorespiratory fitness in population-based studies. © The European Society of Cardiology 2015.

Sequential addition reactions of two molecules of Grignard reagents to thioformamides.

PubMed

Murai, Toshiaki; Ui, Kazuki; Narengerile

2009-08-07

Sequential addition reactions of two molecules of Grignard reagents to thioformamides were found to yield tertiary amines in an efficient manner. The addition of two different Grignard reagents can be accomplished by using one equivalent of arylmagnesium reagent in the first step. In the second step, a variety of reagents such as alkyl, alkenyl, aryl, and alkynyl reagents were used to afford the corresponding amines in good to high yields.

Three critical hydrogen bonds determine the catalytic activity of the Diels–Alderase ribozyme

PubMed Central

Kraut, Stefanie; Bebenroth, Dirk; Nierth, Alexander; Kobitski, Andrei Y.; Nienhaus, G. Ulrich; Jäschke, Andres

2012-01-01

Compared to protein enzymes, our knowledge about how RNA accelerates chemical reactions is rather limited. The crystal structures of a ribozyme that catalyzes Diels–Alder reactions suggest a rich tertiary architecture responsible for catalysis. In this study, we systematically probe the relevance of crystallographically observed ground-state interactions for catalytic function using atomic mutagenesis in combination with various analytical techniques. The largest energetic contribution apparently arises from the precise shape complementarity between transition state and catalytic pocket: A single point mutant that folds correctly into the tertiary structure but lacks one H-bond that normally stabilizes the pocket is completely inactive. In the rate-limiting chemical step, the dienophile is furthermore activated by two weak H-bonds that contribute ∼7–8 kJ/mol to transition state stabilization, as indicated by the 25-fold slower reaction rates of deletion mutants. These H-bonds are also responsible for the tight binding of the Diels–Alder product by the ribozyme that causes product inhibition. For high catalytic activity, the ribozyme requires a fine-tuned balance between rigidity and flexibility that is determined by the combined action of one inter-strand H-bond and one magnesium ion. A sharp 360° turn reminiscent of the T-loop motif observed in tRNA is found to be important for catalytic function. PMID:21976731

Aging Optimization of Aluminum-Lithium Alloy L277 for Application to Cryotank Structures

NASA Technical Reports Server (NTRS)

Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Cho, A.

2003-01-01

Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties and improved damage tolerance. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. A design of experiments aging study was conducted for plate and a limited study on extrusions. To achieve the T8 temper, Alloy L277 is typically aged at 290 F for 40 hours. In the study for plate, a two-step aging treatment was developed through a design of experiments study and the one step aging used as a control. Based on the earlier NASA studies on 2195, the first step aging temperature was varied between 220 F and 260 F. The second step aging temperatures was varied between 290 F and 310 F, which is in the range of the single-step aging temperature. For extrusions, two, single-step, and one two-step aging condition were evaluated. The results of the design of experiments used for the T8 temper as well as a smaller set of experiments for the T6 temper for plate and the results for extrusions will be presented.

Recognition of pigment network pattern in dermoscopy images based on fuzzy classification of pixels.

PubMed

Garcia-Arroyo, Jose Luis; Garcia-Zapirain, Begonya

2018-01-01

One of the most relevant dermoscopic patterns is the pigment network. An innovative method of pattern recognition is presented for its detection in dermoscopy images. It consists of two steps. In the first one, by means of a supervised machine learning process and after performing the extraction of different colour and texture features, a fuzzy classification of pixels into the three categories present in the pattern's definition ("net", "hole" and "other") is carried out. This enables the three corresponding fuzzy sets to be created and, as a result, the three probability images that map them out are generated. In the second step, the pigment network pattern is characterised from a parameterisation process -derived from the system specification- and the subsequent extraction of different features calculated from the combinations of image masks extracted from the probability images, corresponding to the alpha-cuts obtained from the fuzzy sets. The method was tested on a database of 875 images -by far the largest used in the state of the art to detect pigment network- extracted from a public Atlas of Dermoscopy, obtaining AUC results of 0.912 and 88%% accuracy, with 90.71%% sensitivity and 83.44%% specificity. The main contribution of this method is the very design of the algorithm, highly innovative, which could also be used to deal with other pattern recognition problems of a similar nature. Other contributions are: 1. The good performance in discriminating between the pattern and the disturbing artefacts -which means that no prior preprocessing is required in this method- and between the pattern and other dermoscopic patterns; 2. It puts forward a new methodological approach for work of this kind, introducing the system specification as a required step prior to algorithm design and development, being this specification the basis for a required parameterisation -in the form of configurable parameters (with their value ranges) and set threshold values- of the algorithm and the subsequent conducting of the experiments. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Tank Tests of Models of Flying Boat Hulls Having Longitudinal Steps

NASA Technical Reports Server (NTRS)

Allison, John M; Ward, Kenneth E

1936-01-01

Four models with longitudinal steps on the forebody were developed by modification of a model of a conventional hull and were tested in the National Advisory Committee for Aeronautics (NACA) tank. Models with longitudinal steps were found to have smaller resistance at high speed and greater resistance at low speed than the parent model that had the same afterbody but a conventional V-section forebody. The models with a single longitudinal step had better performance at hump speed and as low high-speed resistance except at very light loads. Spray strips at angles from 0 degrees to 45 degrees to the horizontal were fitted at the longitudinal steps and at the chine on one of the two step models having two longitudinal steps. The resistance and the height of the spray were less with each of the spray strips than without; the most favorable angle was found to lie between 15 degrees and 30 degrees.

An emotional contribution to the Festschrift of the Journal of Biomaterials Science for Teiji Tsuruta.

PubMed

Ringsdorf, Helmut

It is a honor for me to contribute to the 'Festschrift for Teiji Tsuruta'! Being old, it is much easier for me to look back than to think ahead. Thus, please allow me to make a few 'historical remarks' about Biomaterials and Biotechnology, long before Science stepped in. Remarks about Georg Christoph Lichtenberg, the Göttinger physicist and philosopher, and his relation to Teiji Tsuruta. And talking about him as teacher, one cannot do it without looking at Hermann Staudinger and his dreams.

Correlation optique en lumiere coherente (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fontanel, A.; Grau, G.

1971-03-01

This paper describes a general bidimensional two-step method of correlation (or convolution) making use of the theory of holography. In the first step the light diffracted by one of the two plane transparent objects to be correlated interferes with the light diffracted by the other one. The hologram thus generated is photographed in the focal image plane of a convergent lens. Owing to the quadratic detection property of the photographic emulsion, the square of the modulus of the product of the spectra of the two objects considered is recorded on the photographic plate. In the second step the convolution productmore » of the two objects appears when the hologram is illuminated with a beam of coherent light. In its geophysical application this optical method of convolution makes it easy for us to obtain the autocorrelogram of a seismic cross-section. This method also makes it possible to correlate each of the seismic traces by special precalculated optically-recorded filters.« less

Extended Attention Span Training System: Video Game Neurotherapy for Attention Deficit Disorder.

ERIC Educational Resources Information Center

Pope, Alan T.; Bogart, Edward H.

1996-01-01

Describes the Extended Attention Span Training (EAST) system for modifying attention deficits, which takes the concept of biofeedback one step further by making a video game more difficult as the player's brain waves indicate that attention is waning. Notes contributions of this technology to neuropsychology and neurology, where the emphasis is on…

Sensitivity Analysis of the Sheet Metal Stamping Processes Based on Inverse Finite Element Modeling and Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Yu, Maolin; Du, R.

2005-08-01

Sheet metal stamping is one of the most commonly used manufacturing processes, and hence, much research has been carried for economic gain. Searching through the literatures, however, it is found that there are still a lots of problems unsolved. For example, it is well known that for a same press, same workpiece material, and same set of die, the product quality may vary owing to a number of factors, such as the inhomogeneous of the workpice material, the loading error, the lubrication, and etc. Presently, few seem able to predict the quality variation, not to mention what contribute to the quality variation. As a result, trial-and-error is still needed in the shop floor, causing additional cost and time delay. This paper introduces a new approach to predict the product quality variation and identify the sensitive design / process parameters. The new approach is based on a combination of inverse Finite Element Modeling (FEM) and Monte Carlo Simulation (more specifically, the Latin Hypercube Sampling (LHS) approach). With an acceptable accuracy, the inverse FEM (also called one-step FEM) requires much less computation load than that of the usual incremental FEM and hence, can be used to predict the quality variations under various conditions. LHS is a statistical method, through which the sensitivity analysis can be carried out. The result of the sensitivity analysis has clear physical meaning and can be used to optimize the die design and / or the process design. Two simulation examples are presented including drawing a rectangular box and drawing a two-step rectangular box.

Comparison of Cryopreservation Protocols (Single and Two-steps) and Thawing (Fast and Slow) for Canine Sperm.

PubMed

Brito, Maíra M; Lúcio, Cristina F; Angrimani, Daniel S R; Losano, João Diego A; Dalmazzo, Andressa; Nichi, Marcílio; Vannucchi, Camila I

2017-01-02

In addition to the existence of several cryopreservation protocols, no systematic research has been carried out in order to confirm the suitable protocol for canine sperm. This study aims to assess the effect of adding 5% glycerol during cryopreservation at 37°C (one-step) and 5°C (two-steps), in addition of testing two thawing protocols (37°C for 30 seconds, and 70°C for 8 seconds). We used 12 sperm samples divided into four experimental groups: Single-Step - Slow Thawing Group; Two-Step - Slow Thawing Group; Single-Step - Fast Thawing Group; and Two-Step - Fast Thawing Group. Frozen-thawed samples were submitted to automated analysis of sperm motility, evaluation of plasmatic membrane integrity, acrosomal integrity, mitochondrial activity, sperm morphology, sperm susceptibility to oxidative stress, and sperm binding assay to perivitellinic membrane of chicken egg yolk. Considering the comparison between freezing protocols, no statistical differences were verified for any of the response variables. When comparison between thawing protocols was performed, slow thawing protocol presented higher sperm count bound to perivitelline membrane of chicken egg yolk, compared to fast thawing protocol. Regardless of the freezing process, the slow thawing protocol can be recommended for the large scale cryopreservation of canine semen, since it shows a consistent better functional result.

Spin-split silicon states at step edges of Si(553)-Au

NASA Astrophysics Data System (ADS)

Biedermann, K.; Regensburger, S.; Fauster, Th.; Himpsel, F. J.; Erwin, S. C.

2012-06-01

The quasi-one-dimensional Si(553)-Au surface is investigated with time-resolved two-photon photoemission and laser-based photoemission. Several occupied and unoccupied states inside and outside the bulk band gap of silicon were found near the center of the surface Brillouin zone. A nondispersing unoccupied state 0.62 eV above the Fermi level with a lifetime of 125 fs matches the spin-split silicon step-edge state predicted by density functional theory calculations. Two occupied bands can be associated with the bands calculated for nonpolarized step-edge atoms.

Dependence of microwave dielectric properties on crystallization behaviour of CaMgSi{sub 2}O{sub 6} glass-ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Bo Kyeong; Jang, Sung Wook; Kim, Eung Soo, E-mail: eskim@kyonggi.ac.kr

2015-07-15

The effects of the crystallization behaviour of CaMgSi{sub 2}O{sub 6} (diopside) glass-ceramics on their microwave dielectric properties were investigated as functions of the Cr{sub 2}O{sub 3} content and heat-treatment method used (one or two steps). The crystallization behaviours of the specimens were affected by the Cr{sub 2}O{sub 3} content as well as by the heat-treatment method employed, and were evaluated using X-ray diffraction and the combined Rietveld and reference intensity ratio (RIR) method. The dielectric constants (K) of the specimens did not change significantly with an increase in the Cr{sub 2}O{sub 3} content. The quality factor (Qf) of the specimensmore » increased for Cr{sub 2}O{sub 3} contents of up to 0.5 wt% Cr{sub 2}O{sub 3}, but then decreased for higher contents. These results could be attributed to the degree of crystallization. For the same Cr{sub 2}O{sub 3} content, the specimens that underwent a two-step heat treatment showed lower K values and higher Qf values than those heat-treated in one-step. These results could be attributed to the smaller crystallite size and higher degree of crystallization in the specimens obtained from the two-step heat treatment compared with those of the specimens heat-treated in one-step method.« less

A simple, compact, and rigid piezoelectric step motor with large step size.

PubMed

Wang, Qi; Lu, Qingyou

2009-08-01

We present a novel piezoelectric stepper motor featuring high compactness, rigidity, simplicity, and any direction operability. Although tested in room temperature, it is believed to work in low temperatures, owing to its loose operation conditions and large step size. The motor is implemented with a piezoelectric scanner tube that is axially cut into almost two halves and clamp holds a hollow shaft inside at both ends via the spring parts of the shaft. Two driving voltages that singly deform the two halves of the piezotube in one direction and recover simultaneously will move the shaft in the opposite direction, and vice versa.

A simple, compact, and rigid piezoelectric step motor with large step size

NASA Astrophysics Data System (ADS)

Wang, Qi; Lu, Qingyou

2009-08-01

We present a novel piezoelectric stepper motor featuring high compactness, rigidity, simplicity, and any direction operability. Although tested in room temperature, it is believed to work in low temperatures, owing to its loose operation conditions and large step size. The motor is implemented with a piezoelectric scanner tube that is axially cut into almost two halves and clamp holds a hollow shaft inside at both ends via the spring parts of the shaft. Two driving voltages that singly deform the two halves of the piezotube in one direction and recover simultaneously will move the shaft in the opposite direction, and vice versa.

A new theory for multistep discretizations of stiff ordinary differential equations: Stability with large step sizes

NASA Technical Reports Server (NTRS)

Majda, G.

1985-01-01

A large set of variable coefficient linear systems of ordinary differential equations which possess two different time scales, a slow one and a fast one is considered. A small parameter epsilon characterizes the stiffness of these systems. A system of o.d.e.s. in this set is approximated by a general class of multistep discretizations which includes both one-leg and linear multistep methods. Sufficient conditions are determined under which each solution of a multistep method is uniformly bounded, with a bound which is independent of the stiffness of the system of o.d.e.s., when the step size resolves the slow time scale, but not the fast one. This property is called stability with large step sizes. The theory presented lets one compare properties of one-leg methods and linear multistep methods when they approximate variable coefficient systems of stiff o.d.e.s. In particular, it is shown that one-leg methods have better stability properties with large step sizes than their linear multistep counter parts. The theory also allows one to relate the concept of D-stability to the usual notions of stability and stability domains and to the propagation of errors for multistep methods which use large step sizes.

Online chemical modeling environment (OCHEM): web platform for data storage, model development and publishing of chemical information

NASA Astrophysics Data System (ADS)

Sushko, Iurii; Novotarskyi, Sergii; Körner, Robert; Pandey, Anil Kumar; Rupp, Matthias; Teetz, Wolfram; Brandmaier, Stefan; Abdelaziz, Ahmed; Prokopenko, Volodymyr V.; Tanchuk, Vsevolod Y.; Todeschini, Roberto; Varnek, Alexandre; Marcou, Gilles; Ertl, Peter; Potemkin, Vladimir; Grishina, Maria; Gasteiger, Johann; Schwab, Christof; Baskin, Igor I.; Palyulin, Vladimir A.; Radchenko, Eugene V.; Welsh, William J.; Kholodovych, Vladyslav; Chekmarev, Dmitriy; Cherkasov, Artem; Aires-de-Sousa, Joao; Zhang, Qing-You; Bender, Andreas; Nigsch, Florian; Patiny, Luc; Williams, Antony; Tkachenko, Valery; Tetko, Igor V.

2011-06-01

The Online Chemical Modeling Environment is a web-based platform that aims to automate and simplify the typical steps required for QSAR modeling. The platform consists of two major subsystems: the database of experimental measurements and the modeling framework. A user-contributed database contains a set of tools for easy input, search and modification of thousands of records. The OCHEM database is based on the wiki principle and focuses primarily on the quality and verifiability of the data. The database is tightly integrated with the modeling framework, which supports all the steps required to create a predictive model: data search, calculation and selection of a vast variety of molecular descriptors, application of machine learning methods, validation, analysis of the model and assessment of the applicability domain. As compared to other similar systems, OCHEM is not intended to re-implement the existing tools or models but rather to invite the original authors to contribute their results, make them publicly available, share them with other users and to become members of the growing research community. Our intention is to make OCHEM a widely used platform to perform the QSPR/QSAR studies online and share it with other users on the Web. The ultimate goal of OCHEM is collecting all possible chemoinformatics tools within one simple, reliable and user-friendly resource. The OCHEM is free for web users and it is available online at http://www.ochem.eu.

Influence of coating steps of perovskite on low-temperature amorphous compact TiO x upon the morphology, crystallinity, and photovoltaic property correlation in planar perovskite solar cells

NASA Astrophysics Data System (ADS)

Shahiduzzaman, Md.; Furumoto, Yoshikazu; Yamamoto, Kohei; Yonezawa, Kyosuke; Azuma, Yosuke; Kitamura, Michinori; Matsuzaki, Hiroyuki; Karakawa, Makoto; Kuwabara, Takayuki; Takahashi, Kohshin; Taima, Tetsuya

2018-03-01

The fabrication of high-efficiency solution-processable perovskite solar cells has been achieved using mesostructured films and compact titanium dioxide (TiO2) layers in a process that involves high temperatures and cost. Here, we present an efficient approach for fabricating chemical-bath-deposited, low-temperature, and low-cost amorphous compact TiO x -based planar heterojunction perovskite solar cells by one-step and two-step coatings of the perovskite layer. We also investigate the effect of the number of perovskite coating steps on the compact TiO x layer. The grazing incidence wide-angle X-ray scattering technique is used to clarify the relationship between morphology, crystallinity, and photovoltaic properties of the resulting devices. Analysis of the films revealed that one-step spin-coating of perovskite exhibited an enhancement of film quality and crystallization that correlates to photovoltaic performance 1.5 times higher than that of a two-step-coated device. Our findings show that the resulting morphology, crystallinity, and device performances are strongly dependent on the number of coating steps of the perovskite thin layer on the compact TiO x layer. This result is useful knowledge for the low-cost production of planar perovskite solar cells.

Accessing FMS Functionality: The Impact of Design on Learning

NASA Technical Reports Server (NTRS)

Fennell, Karl; Sherry, Lance; Roberts, Ralph, Jr.

2004-01-01

In modern commercial and military aircraft, the Flight Management System (FMS) lies at the heart of the functionality of the airplane. The nature of the FMS has also caused great difficulties learning and accessing this functionality. This study examines actual Air Force pilots who were qualified on the newly introduced advanced FMS and shows that the design of the system itself is a primary source of difficulty learning the system. Twenty representative tasks were selected which the pilots could be expected to accomplish on an ' actual flight. These tasks were analyzed using the RAFIV stage model (Sherry, Polson, et al. 2002). This analysis demonstrates that a great burden is placed on remembering complex reformulation of the task to function mapping. 65% of the tasks required retaining one access steps in memory to accomplish the task, 20% required two memorized access steps, and 15% required zero memorized access steps. The probability that a participant would make an access error on the tasks was: two memorized access steps - 74%, one memorized access step - 13%, and zero memorized access steps - 6%. Other factors were analyzed as well, including experience with the system and frequency of use. This completed the picture of a system with many memorized steps causing difficulty with the new system, especially when trying to fine where to access the correct function.

Toxin detection using a fiber-optic-based biosensor

NASA Astrophysics Data System (ADS)

Ogert, Robert A.; Shriver-Lake, Lisa C.; Ligler, Frances S.

1993-05-01

Using an evanescent wave fiber optic-based biosensor developed at Naval Research Laboratory, ricin toxin can be detected in the low ng/ml range. Sensitivity was established at 1 - 5 ng/ml using a two-step assay. The two-step assay showed enhanced signal levels in comparison to a one-step assay. A two-step assay utilizes a 10 minute incubation of an immobilized affinity purified anti-ricin antibody fiber optic probe in the ricin sample before placement in a solution of fluorophore-labeled goat anti-ricin antibodies. The specific fluorescent signal is obtained by the binding of the fluorophore-labeled antibodies to ricin which is bound by the immobilized antibodies on the fiber optic probe. The toxin can be detected directly from urine and river water using this fiber optic assay.

Disruption of striatal-enriched protein tyrosine phosphatase (STEP) function in neuropsychiatric disorders

PubMed Central

Karasawa, Takatoshi; Lombroso, Paul J.

2014-01-01

Striatal-enriched protein tyrosine phosphatase (STEP) is a brain-specific tyrosine phosphatase that plays a major role in the development of synaptic plasticity. Recent findings have implicated STEP in several psychiatric and neurological disorders, including Alzheimer’s disease, schizophrenia, fragile X syndrome, Huntington’s disease, stroke/ischemia, and stress-related psychiatric disorders. In these disorders, STEP protein expression levels and activity are dysregulated, contributing to the cognitive deficits that are present. In this review, we focus on the most recent findings on STEP, discuss how STEP expression and activity are maintained during normal cognitive function, and how disruptions in STEP activity contribute to a number of illnesses. PMID:25218562

Mechanisms of genesis of variant translocation in chronic myeloid leukemia are not correlated with ABL1 or BCR deletion status or response to imatinib therapy.

PubMed

Richebourg, Steven; Eclache, Virginie; Perot, Christine; Portnoi, Marie-France; Van den Akker, Jacqueline; Terré, Christine; Maareck, Odile; Soenen, Valérie; Viguié, Franck; Laï, Jean-Luc; Andrieux, Joris; Corm, Sélim; Roche-Lestienne, Catherine

2008-04-15

Many published studies have indicated that various mechanisms could be involved in the genesis of variant chronic myelogeneous leukemia (CML) translocations. These are mainly one-step or two-step mechanisms, associated or not with deletions adjacent to the translocation junction on der(9) or der(22) chromosomes (or both). Based on the mechanism of genesis, it has been suggested that the complexity may affect the occurrence of ABL1 and BCR deletions (either or both), or may be associated with the CML disease course, and thus could determine the response to imatinib therapy. Through a retrospective molecular cytogenetic study of 41 CML patients with variant Philadelphia chromosome (Ph), we explored the genesis of these variant rearrangements and analyzed the correlation with deletion status and imatinib efficiency. Our results confirmed that the one-step mechanism is the most frequent, evidenced in 30 of 41 patients (73%); 3 patients demonstrated other more complex multistep events and 8 patients (19.5%) harbored ABL1 or BCR deletions that are not significantly associated with the complexity of translocation genesis. We also found no association between one-step, two-step, or multistep mechanisms and the response to imatinib therapy.

Surface energy and surface stress on vicinals by revisiting the Shuttleworth relation

NASA Astrophysics Data System (ADS)

Hecquet, Pascal

2018-04-01

In 1998 [Surf. Sci. 412/413, 639 (1998)], we showed that the step stress on vicinals varies as 1/L, L being the distance between steps, while the inter-step interaction energy primarily follows the law as 1/L2 from the well-known Marchenko-Parshin model. In this paper, we give a better understanding of the interaction term of the step stress. The step stress is calculated with respect to the nominal surface stress. Consequently, we calculate the diagonal surface stresses in both the vicinal system (x, y, z) where z is normal to the vicinal and the projected system (x, b, c) where b is normal to the nominal terrace. Moreover, we calculate the surface stresses by using two methods: the first called the 'Zero' method, from the surface pressure forces and the second called the 'One' method, by homogeneously deforming the vicinal in the parallel direction, x or y, and by calculating the surface energy excess proportional to the deformation. By using the 'One' method on the vicinal Cu(0 1 M), we find that the step deformations, due to the applied deformation, vary as 1/L by the same factor for the tensor directions bb and cb, and by twice the same factor for the parallel direction yy. Due to the vanishing of the surface stress normal to the vicinal, the variation of the step stress in the direction yy is better described by using only the step deformation in the same direction. We revisit the Shuttleworth formula, for while the variation of the step stress in the direction xx is the same between the two methods, the variation in the direction yy is higher by 76% for the 'Zero' method with respect to the 'One' method. In addition to the step energy, we confirm that the variation of the step stress must be taken into account for the understanding of the equilibrium of vicinals when they are not deformed.

Neural correlates of gait variability in people with multiple sclerosis with fall history.

PubMed

Kalron, Alon; Allali, Gilles; Achiron, Anat

2018-05-28

Investigate the association between step time variability and related brain structures in accordance with fall status in people with multiple sclerosis (PwMS). The study included 225 PwMS. A whole-brain MRI was performed by a high-resolution 3.0-Telsa MR scanner in addition to volumetric analysis based on 3D T1-weighted images using the FreeSurfer image analysis suite. Step time variability was measured by an electronic walkway. Participants were defined as "fallers" (at least two falls during the previous year) and "non-fallers". One hundred and five PwMS were defined as fallers and had a greater step time variability compared to non-fallers (5.6% (S.D.=3.4) vs. 3.4% (S.D.=1.5); p=0.001). MS fallers exhibited a reduced volume in the left caudate and both cerebellum hemispheres compared to non-fallers. By using a linear regression analysis no association was found between gait variability and related brain structures in the total cohort and non-fallers group. However, the analysis found an association between the left hippocampus and left putamen volumes with step time variability in the faller group; p=0.031, 0.048, respectively, controlling for total cranial volume, walking speed, disability, age and gender. Nevertheless, according to the hierarchical regression model, the contribution of these brain measures to predict gait variability was relatively small compared to walking speed. An association between low left hippocampal, putamen volumes and step time variability was found in PwMS with a history of falls, suggesting brain structural characteristics may be related to falls and increased gait variability in PwMS. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Quasi-four-body treatment of charge transfer in the collision of protons with atomic helium: I. Thomas related mechanisms

NASA Astrophysics Data System (ADS)

Safarzade, Zohre; Fathi, Reza; Shojaei Akbarabadi, Farideh; Bolorizadeh, Mohammad A.

2018-04-01

The scattering of a completely bare ion by atoms larger than hydrogen is at least a four-body interaction, and the charge transfer channel involves a two-step process. Amongst the two-step interactions of the high-velocity single charge transfer in an anion-atom collision, there is one whose amplitude demonstrates a peak in the angular distribution of the cross sections. This peak, the so-called Thomas peak, was predicted by Thomas in a two-step interaction, classically, which could also be described through three-body quantum mechanical models. This work discusses a four-body quantum treatment of the charge transfer in ion-atom collisions, where two-step interactions illustrating a Thomas peak are emphasized. In addition, the Pauli exclusion principle is taken into account for the initial and final states as well as the operators. It will be demonstrated that there is a momentum condition for each two-step interaction to occur in a single charge transfer channel, where new classical interactions lead to the Thomas mechanism.

Analytical and numerical analysis of frictional damage in quasi brittle materials

NASA Astrophysics Data System (ADS)

Zhu, Q. Z.; Zhao, L. Y.; Shao, J. F.

2016-07-01

Frictional sliding and crack growth are two main dissipation processes in quasi brittle materials. The frictional sliding along closed cracks is the origin of macroscopic plastic deformation while the crack growth induces a material damage. The main difficulty of modeling is to consider the inherent coupling between these two processes. Various models and associated numerical algorithms have been proposed. But there are so far no analytical solutions even for simple loading paths for the validation of such algorithms. In this paper, we first present a micro-mechanical model taking into account the damage-friction coupling for a large class of quasi brittle materials. The model is formulated by combining a linear homogenization procedure with the Mori-Tanaka scheme and the irreversible thermodynamics framework. As an original contribution, a series of analytical solutions of stress-strain relations are developed for various loading paths. Based on the micro-mechanical model, two numerical integration algorithms are exploited. The first one involves a coupled friction/damage correction scheme, which is consistent with the coupling nature of the constitutive model. The second one contains a friction/damage decoupling scheme with two consecutive steps: the friction correction followed by the damage correction. With the analytical solutions as reference results, the two algorithms are assessed through a series of numerical tests. It is found that the decoupling correction scheme is efficient to guarantee a systematic numerical convergence.

Predicting Anthropogenic Noise Contributions to US Waters.

PubMed

Gedamke, Jason; Ferguson, Megan; Harrison, Jolie; Hatch, Leila; Henderson, Laurel; Porter, Michael B; Southall, Brandon L; Van Parijs, Sofie

2016-01-01

To increase understanding of the potential effects of chronic underwater noise in US waters, the National Oceanic and Atmospheric Administration (NOAA) organized two working groups in 2011, collectively called "CetSound," to develop tools to map the density and distribution of cetaceans (CetMap) and predict the contribution of human activities to underwater noise (SoundMap). The SoundMap effort utilized data on density, distribution, acoustic signatures of dominant noise sources, and environmental descriptors to map estimated temporal, spatial, and spectral contributions to background noise. These predicted soundscapes are an initial step toward assessing chronic anthropogenic noise impacts on the ocean's varied acoustic habitats and the animals utilizing them.

Kinetics of Exocytosis Is Faster in Cones Than in Rods

PubMed Central

Rabl, Katalin; Cadetti, Lucia; Thoreson, Wallace B.

2006-01-01

Cone-driven responses of second-order retinal neurons are considerably faster than rod-driven responses. We examined whether differences in the kinetics of synaptic transmitter release from rods and cones may contribute to differences in postsynaptic response kinetics. Exocytosis from rods and cones was triggered by membrane depolarization and monitored in two ways: (1) by measuring EPSCs evoked in second-order neurons by depolarizing steps applied to presynaptic rods or cones during simultaneous paired whole-cell recordings or (2) by direct measurements of exocytotic increases in membrane capacitance. The kinetics of release was assessed by varying the length of the depolarizing test step. Both measures of release revealed two kinetic components to the increase in exocytosis as a function of the duration of a step depolarization. In addition to slow sustained components in both cell types, the initial fast component of exocytosis had a time constant of <5 ms in cones, >10-fold faster than that of rods. Rod/cone differences in the kinetics of release were substantiated by a linear correlation between depolarization-evoked capacitance increases and EPSC charge transfer. Experiments on isolated rods indicate that the slower kinetics of exocytosis from rods was not a result of rod–rod coupling. The initial rapid release of vesicles from cones can shape the postsynaptic response and may contribute to the faster responses of cone-driven cells observed at light offset. PMID:15872111

Virus elimination during the purification of monoclonal antibodies by column chromatography and additional steps.

PubMed

Roberts, Peter L

2014-01-01

The theoretical potential for virus transmission by monoclonal antibody based therapeutic products has led to the inclusion of appropriate virus reduction steps. In this study, virus elimination by the chromatographic steps used during the purification process for two (IgG-1 & -3) monoclonal antibodies (MAbs) have been investigated. Both the Protein G (>7log) and ion-exchange (5 log) chromatography steps were very effective for eliminating both enveloped and non-enveloped viruses over the life-time of the chromatographic gel. However, the contribution made by the final gel filtration step was more limited, i.e., 3 log. Because these chromatographic columns were recycled between uses, the effectiveness of the column sanitization procedures (guanidinium chloride for protein G or NaOH for ion-exchange) were tested. By evaluating standard column runs immediately after each virus spiked run, it was possible to directly confirm that there was no cross contamination with virus between column runs (guanidinium chloride or NaOH). To further ensure the virus safety of the product, two specific virus elimination steps have also been included in the process. A solvent/detergent step based on 1% triton X-100 rapidly inactivating a range of enveloped viruses by >6 log inactivation within 1 min of a 60 min treatment time. Virus removal by virus filtration step was also confirmed to be effective for those viruses of about 50 nm or greater. In conclusion, the combination of these multiple steps ensures a high margin of virus safety for this purification process. © 2014 American Institute of Chemical Engineers.

Parallel algorithms for boundary value problems

NASA Technical Reports Server (NTRS)

Lin, Avi

1990-01-01

A general approach to solve boundary value problems numerically in a parallel environment is discussed. The basic algorithm consists of two steps: the local step where all the P available processors work in parallel, and the global step where one processor solves a tridiagonal linear system of the order P. The main advantages of this approach are two fold. First, this suggested approach is very flexible, especially in the local step and thus the algorithm can be used with any number of processors and with any of the SIMD or MIMD machines. Secondly, the communication complexity is very small and thus can be used as easily with shared memory machines. Several examples for using this strategy are discussed.

Electric fields preceding cloud-to-ground lightning flashes

NASA Astrophysics Data System (ADS)

Beasley, W.; Uman, M. A.; Rustan, P. L., Jr.

1982-06-01

A detailed analysis is presented of the electric-field variations preceding the first return strokes of 80 cloud-to-ground lightning flashes in nine different storms observed at the NASA Kennedy Space Center during the summers of 1976 and 1977. It is suggested that the electric-field variations can best be characterized as having two sections: preliminary variations and stepped leader. The stepped-leader change begins during a transition period of a few milliseconds marked by characteristic bipolar pulses; the duration of stepped leaders lies most frequently in the 6-20 millisecond range. It is also suggested that there is only one type of stepped leader, not two types (alpha and beta) often referred to in the literature.

Comparative evaluation of self-etching primers and phosphoric acid effectiveness on composite to enamel bond: an in vitro study.

PubMed

Patil, Basanagouda S; Rao, Bk Raghavendra; Sharathchandra, Sm; Hegde, Reshma; Kumar, G Vinay

2013-09-01

The aim of the present study was to investigate the effectiveness of the one total-etch self-priming adhesive, one two-step self-etching primer adhesive, and one 'all-in-one' self-etching adhesive system on the adhesion of a resin composite to enamel. Thirty-six freshly extracted human mandibular molars were selected for this study. A fat area about 5 mm in diameter was created on the exposed mesial surface of enamel of each tooth by moist grinding with 320, 420 and 600 grit silicon carbide paper. Twelve teeth were randomly assigned into three groups. In group 1, Adper Easy One (3M ESPE), a one step self-etching primer adhesive was applied and light curing unit for 10 seconds. In group 2, Adper SE Plus, a two-step self-etching primer with bottle A containing the aqueous primer and bottle B containing the acidic adhesive was applied and light cured for 10 seconds. Group 3 (control)-etchant 37% phosphoric acid is applied to the surface for 15 seconds and rinsed with water and air dried and adhesive (single bond 2) is applied to the surface and tube is placed and light cured for 20 seconds. Composite material (Z350) was placed in the tube and light cured for 40 seconds in all the groups. Bond strength testing was done using universal testing machine at the enamel-composite interface. The debonded enamel surface was evaluated in stereomicroscope to assess the cohesive, adhesive or mixed fracture. Data was statistically analyzed by one way analysis of variance (ANOVA). Group 1 performed least among all groups with a mean score of 19.46 MPa. Group 2 had a mean score of 25.67 MPa. Group 3 had a mean score of 27.16 MPa. Under the conditions of this in vitro study, the bond strength values of the two-step self-etching primer systems tested were similar to the total-etch. And, one step self-etching primers have lower bond strength compared to the total-etch.

Fabrication of controlled hierarchical wrinkle structures on polydimethylsiloxane via one-step C4F8 plasma treatment

NASA Astrophysics Data System (ADS)

Miao, Liming; Cheng, Xiaoliang; Chen, Haotian; Song, Yu; Guo, Hang; Zhang, Jinxin; Chen, Xuexian; Zhang, Haixia

2018-01-01

We report a simple method for fabricating two-dimensional and nested hierarchical wrinkle structures on polydimethylsiloxane surfaces via one-step C4F8 plasma treatment that innovatively combines two approaches to monolayer wrinkle structure fabrication. The wavelengths of the two dimensions of the wrinkle structures can be controlled by plasma treatment (radio frequency (RF) power and plasma treatment time) and stretching (stretching strain and axial stretching), respectively. We also analyze the different interactions between the two dimensions of wrinkle structures with different wavelengths and explain the phenomenon using Fourier waveform superposition. The character of the two dimensions and hierarchy is obvious when the wavelengths of the two wrinkles are different. In surface wetting tests, the hierarchical wrinkle shows great hydrophobicity and keeps the stretching property under 25%.

Pedometer determined physical activity tracks in African American adults: The Jackson Heart Study

PubMed Central

2012-01-01

Background This study investigated the number of pedometer assessment occasions required to establish habitual physical activity in African American adults. Methods African American adults (mean age 59.9 ± 0.60 years; 59 % female) enrolled in the Diet and Physical Activity Substudy of the Jackson Heart Study wore Yamax pedometers during 3-day monitoring periods, assessed on two to three distinct occasions, each separated by approximately one month. The stability of pedometer measured PA was described as differences in mean steps/day across time, as intraclass correlation coefficients (ICC) by sex, age, and body mass index (BMI) category, and as percent of participants changing steps/day quartiles across time. Results Valid data were obtained for 270 participants on either two or three different assessment occasions. Mean steps/day were not significantly different across assessment occasions (p values > 0.456). The overall ICCs for steps/day assessed on either two or three occasions were 0.57 and 0.76, respectively. In addition, 85 % (two assessment occasions) and 76 % (three assessment occasions) of all participants remained in the same steps/day quartile or changed one quartile over time. Conclusion The current study shows that an overall mean steps/day estimate based on a 3-day monitoring period did not differ significantly over 4 – 6 months. The findings were robust to differences in sex, age, and BMI categories. A single 3-day monitoring period is sufficient to capture habitual physical activity in African American adults. PMID:22512833

Resolving the problem of trapped water in binding cavities: prediction of host-guest binding free energies in the SAMPL5 challenge by funnel metadynamics

NASA Astrophysics Data System (ADS)

Bhakat, Soumendranath; Söderhjelm, Pär

2017-01-01

The funnel metadynamics method enables rigorous calculation of the potential of mean force along an arbitrary binding path and thereby evaluation of the absolute binding free energy. A problem of such physical paths is that the mechanism characterizing the binding process is not always obvious. In particular, it might involve reorganization of the solvent in the binding site, which is not easily captured with a few geometrically defined collective variables that can be used for biasing. In this paper, we propose and test a simple method to resolve this trapped-water problem by dividing the process into an artificial host-desolvation step and an actual binding step. We show that, under certain circumstances, the contribution from the desolvation step can be calculated without introducing further statistical errors. We apply the method to the problem of predicting host-guest binding free energies in the SAMPL5 blind challenge, using two octa-acid hosts and six guest molecules. For one of the hosts, well-converged results are obtained and the prediction of relative binding free energies is the best among all the SAMPL5 submissions. For the other host, which has a narrower binding pocket, the statistical uncertainties are slightly higher; longer simulations would therefore be needed to obtain conclusive results.

Discrete pre-processing step effects in registration-based pipelines, a preliminary volumetric study on T1-weighted images.

PubMed

Muncy, Nathan M; Hedges-Muncy, Ariana M; Kirwan, C Brock

2017-01-01

Pre-processing MRI scans prior to performing volumetric analyses is common practice in MRI studies. As pre-processing steps adjust the voxel intensities, the space in which the scan exists, and the amount of data in the scan, it is possible that the steps have an effect on the volumetric output. To date, studies have compared between and not within pipelines, and so the impact of each step is unknown. This study aims to quantify the effects of pre-processing steps on volumetric measures in T1-weighted scans within a single pipeline. It was our hypothesis that pre-processing steps would significantly impact ROI volume estimations. One hundred fifteen participants from the OASIS dataset were used, where each participant contributed three scans. All scans were then pre-processed using a step-wise pipeline. Bilateral hippocampus, putamen, and middle temporal gyrus volume estimations were assessed following each successive step, and all data were processed by the same pipeline 5 times. Repeated-measures analyses tested for a main effects of pipeline step, scan-rescan (for MRI scanner consistency) and repeated pipeline runs (for algorithmic consistency). A main effect of pipeline step was detected, and interestingly an interaction between pipeline step and ROI exists. No effect for either scan-rescan or repeated pipeline run was detected. We then supply a correction for noise in the data resulting from pre-processing.

Relationship between thin-film bond strength as measured by a scratch test, and indentation hardness for bonding agents.

PubMed

Kusakabe, Shusuke; Rawls, H Ralph; Hotta, Masato

2016-03-01

To evaluate thin-film bond strength between a bonding agent and human dentin, using a scratch test, and the characteristics and accuracy of measurement. One-step bonding agents (BeautiBond; Bond Force; Adper Easy Bond; Clearfil tri-S Bond) and two-step bonding agents (Cleafil SE Bond; FL-Bond II) were investigated in this study. Flat dentin surfaces were prepared for extracted human molars. The dentin surfaces were ground and bonding agents were applied and light cured. The thin-film bond strength test of the specimens was evaluated by the critical load at which the coated bonding agent failed and dentin appeared. The scratch mark sections were then observed under a scanning electron microscope. Indentation hardness was evaluated by the variation in depth under an applied load of 10gf. Data were compared by one-way ANOVA with the Scheffé's post hoc multiple comparison test (p<0.05). In addition, thin-film bond strength and indentation hardness were analyzed using analysis of correlation and covariance. The thin-film bond strength of two-step bonding agents were found to be significantly higher than that of one-step bonding agents with small standard deviations. Scratch marks consistently showed adhesive failure in the vicinity of the bonding agent/dentin interface. The indentation hardness showed a trend that two-step bonding agents have greater hardness than one-step bonding agents. A moderately significant correlation (r(2)=0.31) was found between thin-film bond strength and indentation hardness. Thin-film bond strength test is a valid and reliable means of evaluating bond strength in the vicinity of the adhesive interface and is more accurate than other methods currently in use. Further, the thin-film bond strength is influenced by the hardness of the cued bonding agent. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Skeletal Diversification via Heteroatom Linkage Control: Preparation of Bicyclic and Spirocyclic Scaffolds from N-Substituted Homopropargyl Alcohols

PubMed Central

Painter, Thomas O.; Bunn, Jonathon R.; Schoenen, Frank J.; Douglas, Justin T.; Day, Victor W.; Santini, Conrad

2013-01-01

The discovery and application of a new branching pathway synthesis strategy that rapidly produces skeletally diverse scaffolds is described. Two different scaffold types, one a bicyclic iodo-vinylidene tertiary amine/tertiary alcohol and the other, a spirocyclic 3-furanone, are each obtained using a two-step sequence featuring a common first step. Both scaffold types lead to intermediates that can be orthogonally diversified using the same final components. One of the scaffold types was obtained in sufficiently high yield that it was immediately used to produce a 97-compound library. PMID:23510238

Skeletal diversification via heteroatom linkage control: preparation of bicyclic and spirocyclic scaffolds from N-substituted homopropargyl alcohols.

PubMed

Painter, Thomas O; Bunn, Jonathon R; Schoenen, Frank J; Douglas, Justin T; Day, Victor W; Santini, Conrad

2013-04-19

The discovery and application of a new branching pathway synthesis strategy that rapidly produces skeletally diverse scaffolds is described. Two different scaffold types, one a bicyclic iodo-vinylidene tertiary amine/tertiary alcohol and the other, a spirocyclic 3-furanone, are each obtained using a two-step sequence featuring a common first step. Both scaffold types lead to intermediates that can be orthogonally diversified using the same final components. One of the scaffold types was obtained in sufficiently high yield that it was immediately used to produce a 97-compound library.

Is a multivariate consensus representation of genetic relationships among populations always meaningful?

PubMed Central

Moazami-Goudarzi, K; Laloë, D

2002-01-01

To determine the relationships among closely related populations or species, two methods are commonly used in the literature: phylogenetic reconstruction or multivariate analysis. The aim of this article is to assess the reliability of multivariate analysis. We describe a method that is based on principal component analysis and Mantel correlations, using a two-step process: The first step consists of a single-marker analysis and the second step tests if each marker reveals the same typology concerning population differentiation. We conclude that if single markers are not congruent, the compromise structure is not meaningful. Our model is not based on any particular mutation process and it can be applied to most of the commonly used genetic markers. This method is also useful to determine the contribution of each marker to the typology of populations. We test whether our method is efficient with two real data sets based on microsatellite markers. Our analysis suggests that for closely related populations, it is not always possible to accept the hypothesis that an increase in the number of markers will increase the reliability of the typology analysis. PMID:12242255

One-step formation of w/o/w multiple emulsions stabilized by single amphiphilic block copolymers.

PubMed

Hong, Liangzhi; Sun, Guanqing; Cai, Jinge; Ngai, To

2012-02-07

Multiple emulsions are complex polydispersed systems in which both oil-in-water (O/W) and water-in-oil (W/O) emulsion exists simultaneously. They are often prepared accroding to a two-step process and commonly stabilized using a combination of hydrophilic and hydrophobic surfactants. Recently, some reports have shown that multiple emulsions can also be produced through one-step method with simultaneous occurrence of catastrophic and transitional phase inversions. However, these reported multiple emulsions need surfactant blends and are usually described as transitory or temporary systems. Herein, we report a one-step phase inversion process to produce water-in-oil-in-water (W/O/W) multiple emulsions stabilized solely by a synthetic diblock copolymer. Unlike the use of small molecule surfactant combinations, block copolymer stabilized multiple emulsions are remarkably stable and show the ability to separately encapsulate both polar and nonpolar cargos. The importance of the conformation of the copolymer surfactant at the interfaces with regards to the stability of the multiple emulsions using the one-step method is discussed.

Diffusion welding. [heat treatment of nickel alloys following single step vacuum welding process

NASA Technical Reports Server (NTRS)

Holko, K. H. (Inventor)

1974-01-01

Dispersion-strengthened nickel alloys are sanded on one side and chemically polished. This is followed by a single-step welding process wherein the polished surfaces are forced into intimate contact at 1,400 F for one hour in a vacuum. Diffusion, recrystallization, and grain growth across the original weld interface are obtained during postheating at 2,150 F for two hours in hydrogen.

Influence of the Preparation Method on Planar Perovskite CH3NH3PbI3-xClx Solar Cell Performance and Hysteresis

NASA Astrophysics Data System (ADS)

Ivanova, A.; Tokmakov, A.; Lebedeva, K.; Roze, M.; Kaulachs, I.

2017-08-01

Organometal halide perovskites are promising materials for lowcost, high-efficiency solar cells. The method of perovskite layer deposition and the interfacial layers play an important role in determining the efficiency of perovskite solar cells (PSCs). In the paper, we demonstrate inverted planar perovskite solar cells where perovskite layers are deposited by two-step modified interdiffusion and one-step methods. We also demonstrate how PSC parameters change by doping of charge transport layers (CTL). We used dimethylsupoxide (DMSO) as dopant for the hole transport layer (PEDOT:PSS) but for the electron transport layer [6,6]-phenyl C61 butyric acid methyl ester (PCBM)) we used N,N-dimethyl-N-octadecyl(3-aminopropyl)trimethoxysilyl chloride (DMOAP). The highest main PSC parameters (PCE, EQE, VOC) were obtained for cells prepared by the one-step method with fast crystallization and doped CTLs but higher fill factor (FF) and shunt resistance (Rsh) values were obtained for cells prepared by the two-step method with undoped CTLs.

[Application of ordinary Kriging method in entomologic ecology].

PubMed

Zhang, Runjie; Zhou, Qiang; Chen, Cuixian; Wang, Shousong

2003-01-01

Geostatistics is a statistic method based on regional variables and using the tool of variogram to analyze the spatial structure and the patterns of organism. In simulating the variogram within a great range, though optimal simulation cannot be obtained, the simulation method of a dialogue between human and computer can be used to optimize the parameters of the spherical models. In this paper, the method mentioned above and the weighted polynomial regression were utilized to simulate the one-step spherical model, the two-step spherical model and linear function model, and the available nearby samples were used to draw on the ordinary Kriging procedure, which provided a best linear unbiased estimate of the constraint of the unbiased estimation. The sum of square deviation between the estimating and measuring values of varying theory models were figured out, and the relative graphs were shown. It was showed that the simulation based on the two-step spherical model was the best simulation, and the one-step spherical model was better than the linear function model.

Bioleaching of incineration fly ash by Aspergillus niger - precipitation of metallic salt crystals and morphological alteration of the fungus.

PubMed

Xu, Tong-Jiang; Ramanathan, Thulasya; Ting, Yen-Peng

2014-09-01

This study examines the bioleaching of municipal solid waste incineration fly ash by Aspergillus niger , and its effect on the fungal morphology, the fate of the ash particles, and the precipitation of metallic salt crystals during bioleaching. The fungal morphology was significantly affected during one-step and two-step bioleaching; scanning electron microscopy revealed that bioleaching caused distortion of the fungal hyphae (with up to 10 μm hyphae diameter) and a swollen pellet structure. In the absence of the fly ash, the fungi showed a linear structure (with 2-4 μm hyphae diameter). Energy-dispersive X-ray spectroscopy and X-ray diffraction confirmed the precipitation of calcium oxalate hydrate crystals at the surface of hyphae in both one-step and two-step bioleaching. Calcium oxalate precipitation affects bioleaching via the weakening of the fly ash, thus facilitating the release of other tightly bound metals in the matrix.

Tunable dichroic polarization beam splitter created by one-step holographic photoalignment using four-beam polarization interferometry

NASA Astrophysics Data System (ADS)

Kawai, Kotaro; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

2017-01-01

A tunable dichroic polarization beam splitter (tunable DPBS) simultaneously performs the follow functions: 1. Separation of a polarized incident beam into multiple pairs of orthogonally polarized beams; 2. Separation of the propagation direction of two wavelength incident beams after passing through the tunable DPBS; and 3. Control of both advanced polarization and wavelength separation capabilities by varying the temperature of the tunable DPBS. This novel complex optical property is realized by diffraction phenomena using a designed three-dimensional periodic structure of aligned liquid crystals in the tunable DPBS, which was fabricated quickly with precision in a one-step photoalignment using four-beam polarization interferometry. In experiments, we demonstrated that these diffraction properties are obtained by entering polarized beams of wavelengths 532 nm and 633 nm onto the tunable DPBS. These diffraction properties are described using the Jones calculus in a polarization propagation analysis. Of significance is that the aligned liquid crystal structure needed to obtain these diffraction properties was proposed based on a theoretical analysis, and these properties were then demonstrated experimentally. The tunable DPBS can perform several functions of a number of optical elements such as wave plates, polarization beam splitter, dichroic beam splitter, and tunable wavelength filter. Therefore, the tunable DPBS can contribute to greater miniaturization, sophistication, and cost reduction of optical systems used widely in applications, such as optical measurements, communications, and information processing.

Space Science

NASA Image and Video Library

1994-11-01

An international effort to learn more about the complex interaction between the Earth and Sun took another step forward with the launch of WIND spacecraft from Kennedy Space Center (KSC). WIND spacecraft is studded with eight scientific instruments - six US, one French, and one - the first Russian instrument to fly on a US spacecraft - that collected data about the influence of the solar wind on the Earth and its atmosphere. WIND is part of the Global Geospace Science (GGS) initiative, the US contribution to NASA's International Solar Terrestrial Physics (ISTP) program.

WIND Spacecraft Launch

NASA Technical Reports Server (NTRS)

1994-01-01

An international effort to learn more about the complex interaction between the Earth and Sun took another step forward with the launch of WIND spacecraft from Kennedy Space Center (KSC). WIND spacecraft is studded with eight scientific instruments - six US, one French, and one - the first Russian instrument to fly on a US spacecraft - that collected data about the influence of the solar wind on the Earth and its atmosphere. WIND is part of the Global Geospace Science (GGS) initiative, the US contribution to NASA's International Solar Terrestrial Physics (ISTP) program.

One Step Quantum Key Distribution Based on EPR Entanglement

PubMed Central

Li, Jian; Li, Na; Li, Lei-Lei; Wang, Tao

2016-01-01

A novel quantum key distribution protocol is presented, based on entanglement and dense coding and allowing asymptotically secure key distribution. Considering the storage time limit of quantum bits, a grouping quantum key distribution protocol is proposed, which overcomes the vulnerability of first protocol and improves the maneuverability. Moreover, a security analysis is given and a simple type of eavesdropper’s attack would introduce at least an error rate of 46.875%. Compared with the “Ping-pong” protocol involving two steps, the proposed protocol does not need to store the qubit and only involves one step. PMID:27357865

Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin.

PubMed

Jiang, Qianzhou; Chen, Minle; Ding, Jiangfeng

2013-12-01

This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin.

Molecular detection assay of five Salmonella serotypes of public interest: Typhimurium, Enteritidis, Newport, Heidelberg, and Hadar.

PubMed

Bugarel, M; Tudor, A; Loneragan, G H; Nightingale, K K

2017-03-01

Foodborne illnesses due to Salmonella represent an important public-health concern worldwide. In the United States, a majority of Salmonella infections are associated with a small number of serotypes. Furthermore, some serotypes that are overrepresented among human disease are also associated with multi-drug resistance phenotypes. Rapid detection of serotypes of public-health concern might help reduce the burden of salmonellosis cases and limit exposure to multi-drug resistant Salmonella. We developed a two-step real-time PCR-based rapid method for the identification and detection of five Salmonella serotypes that are either overrepresented in human disease or frequently associated with multi-drug resistance, including serotypes Enteritidis, Typhimurium, Newport, Hadar, and Heidelberg. Two sets of four markers were developed to detect and differentiate the five serotypes. The first set of markers was developed as a screening step to detect the five serotypes; whereas, the second set was used to further distinguish serotypes Heidelberg, Newport and Hadar. The utilization of these markers on a two-step investigation strategy provides a diagnostic specificity of 97% for the detection of Typhimurium, Enteritidis, Heidelberg, Infantis, Newport and Hadar. The diagnostic sensitivity of the detection makers is >96%. The availability of this two-step rapid method will facilitate specific detection of Salmonella serotypes that contribute to a significant proportion of human disease and carry antimicrobial resistance. Published by Elsevier B.V.

Facile one-step construction of covalently networked, self-healable, and transparent superhydrophobic composite films

NASA Astrophysics Data System (ADS)

Lee, Yujin; You, Eun-Ah; Ha, Young-Geun

2018-07-01

Despite the considerable demand for bioinspired superhydrophobic surfaces with highly transparent, self-cleaning, and self-healable properties, a facile and scalable fabrication method for multifunctional superhydrophobic films with strong chemical networks has rarely been established. Here, we report a rationally designed facile one-step construction of covalently networked, transparent, self-cleaning, and self-healable superhydrophobic films via a one-step preparation and single-reaction process of multi-components. As coating materials for achieving the one-step fabrication of multifunctional superhydrophobic films, we included two different sizes of Al2O3 nanoparticles for hierarchical micro/nano dual-scale structures and transparent films, fluoroalkylsilane for both low surface energy and covalent binding functions, and aluminum nitrate for aluminum oxide networked films. On the basis of stability tests for the robust film composition, the optimized, covalently linked superhydrophobic composite films with a high water contact angle (>160°) and low sliding angle (<1°) showed excellent thermal stability (up to 400 °C), transparency (≈80%), self-healing, self-cleaning, and waterproof abilities. Therefore, the rationally designed, covalently networked superhydrophobic composite films, fabricated via a one-step solution-based process, can be further utilized for various optical and optoelectronic applications.

Processes regulating the initiation and postejaculatory resumption of copulatory behavior in male hamsters.

PubMed

Floody, Owen R

2014-06-01

Studies using factor analysis have helped describe the organization of copulatory behavior in male rodents. However, the focus of these studies on a few traditional measures may have limited their results. To test this possibility, 74 sexually-experienced male hamsters were observed as they copulated with stimulus females. The measures collected exceeded the conventional ones in number, variety and independence. The factor analysis of these data revealed a structure with seven factors collectively accounting for 80% of the variance. Most resembled the factors in previous reports, reinforcing the contributions that the processes suggested by these factors make to the organization of male behavior. But several other factors were more novel, possibly reflecting the use of measures that were novel or revised for greater independence. The most interesting of these were two factors focusing on early steps in the progression leading to ejaculation. Importantly, both incorporated measures from each of the three copulatory series that were observed. Past work suggests that independent processes control the times required to initiate copulation and later resume it after an ejaculation. In contrast, these results suggest the existence of two processes, each of which contributes to both the initiation and reinitiation of copulation. Copyright © 2014 Elsevier B.V. All rights reserved.

The appropriateness of use of percutaneous transluminal coronary angioplasty in Spain.

PubMed

Aguilar, M D; Fitch, K; Lázaro, P; Bernstein, S J

2001-05-01

The rapid increase in the number of percutaneous transluminal coronary angioplasty (PTCA) procedures performed in Spain in recent years raises questions about how appropriately this procedure is being used. To examine this issue, we studied the appropriateness of use of PTCA in Spanish patients and factors associated with inappropriate use. We applied criteria for the appropriate use of PTCA developed by an expert panel of Spanish cardiologists and cardiovascular surgeons to a random sample of 1913 patients undergoing PTCA in Spain in 1997. The patients were selected through a two-step sampling process, stratifying by hospital type (public/private) and volume of procedures (low/medium/high). We examined the association between inappropriate use of PTCA and different clinical and sociodemographic factors. Overall, 46% of the PTCA procedures were appropriate, 31% were uncertain and 22% were inappropriate. Two factors contributing to inappropriate use were patients' receipt of less than optimal medical therapy and their failure to undergo stress testing. Institutional type and volume of procedures were not significantly related with inappropriate use. One of every five PTCA procedures in Spain is done for inappropriate reasons. Assuring that patients receive optimal medical therapy and undergo stress testing when indicated could contribute to more appropriate use of PTCA.

Microphysical Timescales in Clouds and their Application in Cloud-Resolving Modeling

NASA Technical Reports Server (NTRS)

Zeng, Xiping; Tao, Wei-Kuo; Simpson, Joanne

2007-01-01

Independent prognostic variables in cloud-resolving modeling are chosen on the basis of the analysis of microphysical timescales in clouds versus a time step for numerical integration. Two of them are the moist entropy and the total mixing ratio of airborne water with no contributions from precipitating particles. As a result, temperature can be diagnosed easily from those prognostic variables, and cloud microphysics be separated (or modularized) from moist thermodynamics. Numerical comparison experiments show that those prognostic variables can work well while a large time step (e.g., 10 s) is used for numerical integration.

Mapping of within-species segregation distortion in Drosophila persimilis and hybrid sterility between D. persimilis and D. pseudoobscura.

PubMed

McDermott, S R; Noor, M A F

2012-10-01

In contrast to the prevailing dogma in the 1990s, recent studies have suggested that an evolutionary history of segregation distortion within species may contribute to sterility in species hybrids. However, this recent work identified segregation distortion exclusively in species hybrids that may never have had an evolutionary history of segregation distortion in either parent species. We expand on previous work using a strain of Drosophila persimilis exhibiting segregation distortion within species to generate QTL maps for segregation distortion and hybrid sterility in crosses between D. persimilis and D. pseudoobscura. The maps localize regions along the XR contributing to both phenotypes, and they indicate one region of overlap between the two maps. This overlap could provide preliminary evidence for an association between segregation distortion within species and hybrid sterility, but the localizations are currently too broad to have confidence in this conclusion. This work is a first step towards possibly supporting a genetic conflict model of speciation in this system. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

To amend the Internal Revenue Code of 1986 to extend for one year the enhanced charitable deduction for contributions of food inventory.

THOMAS, 113th Congress

Rep. Grayson, Alan [D-FL-9

2014-01-28

House - 01/28/2014 Referred to the House Committee on Ways and Means. (All Actions) Notes: For further action, see H.R.5771, which became Public Law 113-295 on 12/19/2014. Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

One Step Closer: Understanding the Complex Relationship between Weight and Self-Esteem in Ethnically Diverse Preadolescent Girls

ERIC Educational Resources Information Center

Erickson, Sarah J.; Hahn-Smith, Anne; Smith, Jane Ellen

2009-01-01

Empirical support for the association between childhood overweight and low self-esteem is equivocal. The present study investigated how weight, ethnicity, body esteem, body dissatisfaction, and disordered eating attitudes/behaviors contribute to global and dimensional self-esteem in a non-clinical sample of Hispanic- and Anglo-American grade 3-6…

Mechanisms of formation of 8-oxoguanine due to reactions of one and two OH* radicals and the H2O2 molecule with guanine: A quantum computational study.

PubMed

Jena, N R; Mishra, P C

2005-07-28

Mechanisms of formation of the mutagenic product 8-oxoguanine (8OG) due to reactions of guanine with two separate OH* radicals and with H2O2 were investigated at the B3LYP/6-31G, B3LYP/6-311++G, and B3LYP/AUG-cc-pVDZ levels of theory. Single point energy calculations were carried out with the MP2/AUG-cc-pVDZ method employing the optimized geometries at the B3LYP/AUG-cc-pVDZ level. Solvent effect was treated using the PCM and IEF-PCM models. Reactions of two separate OH* radicals and H2O2 with the C2 position of 5-methylimidazole (5MI) were investigated taking 5MI as a model to study reactions at the C8 position of guanine. The addition reaction of an OH* radical at the C8 position of guanine is found to be nearly barrierless while the corresponding adduct is quite stable. The reaction of a second OH* radical at the C8 position of guanine leading to the formation of 8OG complexed with a water molecule can take place according to two different mechanisms, involving two steps each. According to one mechanism, at the first step, 8-hydroxyguanine (8OHG) complexed with a water molecule is formed ,while at the second step, 8OHG is tautomerized to 8OG. In the other mechanism, at the first step, an intermediate complexed (IC) with a water molecule is formed, the five-membered ring of which is open, while at the second step, the five-membered ring is closed and a hydrogen bonded complex of 8OG with a water molecule is formed. The reaction of H2O2 with guanine leading to the formation of 8OG complexed with a water molecule can also take place in accordance with two different mechanisms having two steps each. At the first step of one mechanism, H2O2 is dissociated into two OH* groups that react with guanine to form the same IC as that formed in the reaction with two separate OH* radicals, and the subsequent step of this mechanism is also the same as that of the reaction of guanine with two separate OH* radicals. At the first step of the other mechanism of the reaction of guanine with H2O2, the latter molecule is dissociated into a hydrogen atom and an OOH* group which become bonded to the N7 and C8 atoms of guanine, respectively. At the second step of this mechanism, the OOH* group is dissociated into an oxygen atom and an OH* group, the former becomes bonded to the C8 atom of guanine while the latter abstracts the H8 atom bonded to C8, thus producing 8OG complexed with a water molecule. Solvent effects of the aqueous medium on certain reaction barriers and released energies are appreciable. 5MI works as a satisfactory model for a qualitative study of the reactions of two separate OH* radicals or H2O2 occurring at the C8 position of guanine.

Polar motion excitation analysis due to global continental water redistribution

NASA Astrophysics Data System (ADS)

Fernandez, L.; Schuh, H.

2006-10-01

We present the results obtained when studying the hydrological excitation of the Earth‘s wobble due to global redistribution of continental water storage. This work was performed in two steps. First, we computed the hydrological angular momentum (HAM) time series based on the global hydrological model LaD (Land Dynamics model) for the period 1980 till 2004. Then, we compared the effectiveness of this excitation by analysing the residuals of the geodetic time series after removing atmospheric and oceanic contributions with the respective hydrological ones. The emphasis was put on low frequency variations. We also present a comparison of HAM time series from LaD with respect to that one from a global model based on the assimilated soil moisture and snow accumulation data from NCEP/NCAR (The National Center for Environmental Prediction/The National Center for Atmospheric Research) reanalysis. Finally, we evaluate the performance of LaD model in closing the polar motion budget at seasonal periods in comparison with the NCEP and the Land Data Assimilation System (LDAS) models.

Biosorption of Pb(II) Ions by Klebsiella sp. 3S1 Isolated from a Wastewater Treatment Plant: Kinetics and Mechanisms Studies

PubMed Central

Muñoz, Antonio Jesús; Espínola, Francisco; Moya, Manuel; Ruiz, Encarnación

2015-01-01

Lead biosorption by Klebsiella sp. 3S1 isolated from a wastewater treatment plant was investigated through a Rotatable Central Composite Experimental Design. The optimisation study indicated the following optimal values of operating variables: 0.4 g/L of biosorbent dosage, pH 5, and 34°C. According to the results of the kinetic studies, the biosorption process can be described by a two-step process, one rapid, almost instantaneous, and one slower, both contributing significantly to the overall biosorption; the model that best fits the experimental results was pseudo-second order. The equilibrium studies showed a maximum lead uptake value of 140.19 mg/g according to the Langmuir model. The mechanism study revealed that lead ions were bioaccumulated into the cytoplasm and adsorbed on the cell surface. The bacterium  Klebsiella sp. 3S1 has a good potential in the bioremoval of lead in an inexpensive and effective process. PMID:26504824

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

PubMed Central

Wu, Mei; Hardman, Ailsa; Lilienkampf, Annamaria; Pernagallo, Salvatore; Blakely, Garry; Swann, David G.; Bradley, Mark; Gallagher, Maurice P.

2016-01-01

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important. PMID:27842360

Effects of stair-climbing on balance, gait, strength, resting heart rate, and submaximal endurance in healthy seniors.

PubMed

Donath, L; Faude, O; Roth, R; Zahner, L

2014-04-01

Stair-climbing serves as a feasible opportunity to remain physically active within everyday-life. Data on neuromuscular and cardiorespiratory performance after regular stair-climbing in seniors are scarce. Forty-eight seniors were stratified to a one- (taking every step, INT1) or two-step strategy (every second step, INT2) or a control group (CON). Thirty-nine seniors [females: n = 22, males: n = 17; age: 70.5 (SD 5.1) years; BMI: 25.8 (3.1) kg/m(2)] completed the 8-week intervention (three weekly sessions). Before and after the intervention, balance, gait, strength, and submaximal endurance (at different intensities) were assessed. Maximal strength and explosive power did not improve significantly (0.10 < P < 0.78). Resting heart rate was significantly reduced in INT2 (-8/min) compared with INT1 (0/min, P = 0.02) and CON (0/min, P = 0.03). Compared with CON, perceived exertion for all intensities (0.007 < P < 0.03) and submaximal exercise heart rate during moderate uphill walking significantly decreased (-11/min; P < 0.05) in INT2. Step counts for forward beam balancing (4.5 cm width) increased in INT2 (P = 0.007) compared with CON. With more pronounced effects in INT2, stair-climbing significantly improved resting and exercise heart rates, perceived exertion, and dynamic balance performance in healthy seniors and may contribute to better overall fitness, reduced fall risk, and less perceived strain during daily life activities. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Divergent Synthesis of Quinolone Natural Products from Pseudonocardia sp. CL38489.

PubMed

Geddis, Stephen M; Carro, Laura; Hodgkinson, James T; Spring, David R

2016-12-01

Two divergent synthetic routes are reported offering access to four quinolone natural products from Pseudonocardia sp. CL38489. Key steps to the natural products involved a regioselective epoxidation, an intramolecular Buchwald-Hartwig amination and a final acid-catalysed 1,3-allylic-alcohol rearrangement to give two of the natural products in one step. This study completes the synthesis of all eight antibacterial quinolone natural products reported in the family. In addition, this modular strategy enables an improved synthesis towards two natural products previously reported.

Particle simulation of Coulomb collisions: Comparing the methods of Takizuka and Abe and Nanbu

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Chiaming; Lin, Tungyou; Caflisch, Russel

2008-04-20

The interactions of charged particles in a plasma are governed by long-range Coulomb collision. We compare two widely used Monte Carlo models for Coulomb collisions. One was developed by Takizuka and Abe in 1977, the other was developed by Nanbu in 1997. We perform deterministic and statistical error analysis with respect to particle number and time step. The two models produce similar stochastic errors, but Nanbu's model gives smaller time step errors. Error comparisons between these two methods are presented.

A novel one-step Helicobacter pylori saliva antigen test.

PubMed

Yang, Bi-Ling; Yeh, Chun; Kwong, Wei-Gang; Lee, Shou-Dong

2015-02-01

A rapid, reliable, and sufficiently accurate test for diagnosing Helicobacter pylori infection is required for screening dyspeptic patients before a referral for endoscopy. The purpose of this article is two-fold: first, to evaluate the accuracy of a one-step H. pylori saliva antigen (HPS) test; and second, to compare noninvasive and invasive H. pylori tests in Taiwanese population. A total of 104 consecutive dyspeptic patients admitted for gastroenterology into the outpatient department underwent a one-step HPS test, rapid urease test, histology, and (13)C-urea breath test (13)C-UBT (proto C-13 urea kit). The accuracy of the HPS test was compared with a gold standard defined by at least two positive H. pylori test results from three H. pylori tests (histology, rapid urease test, and (13)C-UBT). The 104 patients eligible for analysis (mean age: 58 years, range 22-87 years), 21 (20%) were gold standard positive. Among them, the positive of the one-step H. pylori saliva Ag test, rapid urease test, (13)C-UBT, histology were (52; 50%), (17; 16%), (27; 25%) and (22; 21%) respectively. The sensitivity and specificity of the HPS tests, rapid urease test, (13)C-UBTs, and histology were 71.43% and 55.42%, 76.19% and 98.80%, 100% and 92.77%, and 85.71% and 95.18%, respectively, relative to the gold standard. The one-step HPS test exhibited a sensitivity of 71.43%, nearly equivalent to that of the rapid urea test. The one-step HPS test exhibited a high sensitivity and low specificity compared with the other tests, indicating that it is not sufficiently accurate for use in a clinical setting for diagnosing H. pylori infection. However, the test is simple to use (requiring only a saliva sample), inexpensive, and noninvasive in its application, and thus appealing for use in population-based prevalence surveys of the epidemiology of H. pylori infection. Copyright © 2014. Published by Elsevier Taiwan.

A permeation theory for single-file ion channels: one- and two-step models.

PubMed

Nelson, Peter Hugo

2011-04-28

How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al., PNAS 107, 5833 (2010)]. These previously published simulation data are fitted to a one-step knock-on model that successfully explains the highly non-Ohmic current-voltage curve observed in the simulation. However, these predictions (and the simulations upon which they are based) are not representative of real channel behavior, which is typically Ohmic at low voltages. A two-step association/dissociation (A/D) model is then compared with experiment for the first time. This two-parameter model is shown to be remarkably consistent with previously published permeation experiments through the MaxiK potassium channel over a wide range of concentrations and positive voltages. The A/D model also provides a first-order explanation of permeation through the Shaker potassium channel, but it does not explain the asymmetry observed experimentally. To address this, a new asymmetric variant of the A/D model is developed using the present theoretical framework. It includes a third parameter that represents the value of the "permeation coordinate" (fractional electric potential energy) corresponding to the triply occupied state n of the channel. This asymmetric A/D model is fitted to published permeation data through the Shaker potassium channel at physiological concentrations, and it successfully predicts qualitative changes in the negative current-voltage data (including a transition to super-Ohmic behavior) based solely on a fit to positive-voltage data (that appear linear). The A/D model appears to be qualitatively consistent with a large group of published MD simulations, but no quantitative comparison has yet been made. The A/D model makes a network of predictions for how the elementary steps and the channel occupancy vary with both concentration and voltage. In addition, the proposed theoretical framework suggests a new way of plotting the energetics of the simulated system using a one-dimensional permeation coordinate that uses electric potential energy as a metric for the net fractional progress through the permeation mechanism. This approach has the potential to provide a quantitative connection between atomistic simulations and permeation experiments for the first time.

FMRQ-A Multiagent Reinforcement Learning Algorithm for Fully Cooperative Tasks.

PubMed

Zhang, Zhen; Zhao, Dongbin; Gao, Junwei; Wang, Dongqing; Dai, Yujie

2017-06-01

In this paper, we propose a multiagent reinforcement learning algorithm dealing with fully cooperative tasks. The algorithm is called frequency of the maximum reward Q-learning (FMRQ). FMRQ aims to achieve one of the optimal Nash equilibria so as to optimize the performance index in multiagent systems. The frequency of obtaining the highest global immediate reward instead of immediate reward is used as the reinforcement signal. With FMRQ each agent does not need the observation of the other agents' actions and only shares its state and reward at each step. We validate FMRQ through case studies of repeated games: four cases of two-player two-action and one case of three-player two-action. It is demonstrated that FMRQ can converge to one of the optimal Nash equilibria in these cases. Moreover, comparison experiments on tasks with multiple states and finite steps are conducted. One is box-pushing and the other one is distributed sensor network problem. Experimental results show that the proposed algorithm outperforms others with higher performance.

Predictors of symptom congruence among patients with acute myocardial infarction.

PubMed

Fox-Wasylyshyn, Susan

2012-01-01

The extent of congruence between one's symptom experience and preconceived ideas about the nature of myocardial infarction symptoms (ie, symptom congruence) can influence when acute myocardial infarction (AMI) patients seek medical care. Lengthy delays impede timely receipt of medical interventions and result in greater morbidity and mortality. However, little is known about the factors that contribute to symptom congruence. Hence, the purpose of this study was to examine how AMI patients' symptom experiences and patients' demographic and clinical characteristics contribute to symptom congruence. Secondary data analyses were performed on interview data that were collected from 135 AMI patients. Hierarchical multiple regression analyses were used to examine how specific symptom attributes and demographic and clinical characteristics contribute to symptom congruence. Chest pain/discomfort and other symptom variables (type and location) were included in step 1 of the analysis, whereas symptom severity and demographic and clinical factors were included in step 2. In a second analysis, quality descriptors of discomfort replaced chest pain/discomfort in step 1. Although chest pain/discomfort, and quality descriptors of heaviness and cutting were significant in step 1 of their respective analyses, all became nonsignificant when the variables in step 2 were added to the analyses. Severe discomfort (β = .29, P < .001), history of AMI (β = .21, P < .01), and male sex (β = .17, P < .05) were significant predictors of symptom congruence in the first analysis. Only severe discomfort (β = .23, P < .01) and history of AMI (β = .17, P < .05) were predictive of symptom congruence in the second analysis. Although the location and quality of discomfort were important components of symptom congruence, symptom severity outweighed their importance. Nonsevere symptoms were less likely to meet the expectations of AMI symptoms by those experiencing this event. Those without a previous history of AMI also experienced lower levels of symptom congruence. Implications pertaining to these findings are discussed.

Continuum modeling of three-dimensional truss-like space structures

NASA Technical Reports Server (NTRS)

Nayfeh, A. H.; Hefzy, M. S.

1978-01-01

A mathematical and computational analysis capability has been developed for calculating the effective mechanical properties of three-dimensional periodic truss-like structures. Two models are studied in detail. The first, called the octetruss model, is a three-dimensional extension of a two-dimensional model, and the second is a cubic model. Symmetry considerations are employed as a first step to show that the specific octetruss model has four independent constants and that the cubic model has two. The actual values of these constants are determined by averaging the contributions of each rod element to the overall structure stiffness. The individual rod member contribution to the overall stiffness is obtained by a three-dimensional coordinate transformation. The analysis shows that the effective three-dimensional elastic properties of both models are relatively close to each other.

Connections: A Journal of Adult Literacy. Volume II.

ERIC Educational Resources Information Center

Connections: A Journal of Adult Literacy, 1987

1987-01-01

The articles in this issue include "Let's Talk about What This Means" (Duncan); "Dyslexia and Adult Literacy--Forging the Missing Link" (Kidder); "Competency-Based ESL, One Step Forward or Two Steps Back?" (Auerbach); " A Comparative Look at Adult Literacy Programs in Stockholm, London, and Boston" (Nickse);…

Enzymatic enrichment of egg-yolk phosphatidylcholine with alpha-linolenic acid.

PubMed

Chojnacka, A; Gładkowski, W; Kiełbowicz, G; Wawrzeńczyk, C

2009-05-01

alpha-Linolenic acid (ALA) was incorporated at 28% into the sn-1 position of egg-yolk phospatidylcholine using Novozyme 435 in one-step transesterification process. Using phospholipase A(2) in a two-step process gave 25% incorporation of ALA into the sn-2 position.

One-Step Real-Image Reflection Holograms

ERIC Educational Resources Information Center

Buah-Bassuah, Paul K.; Vannoni, Maurizio; Molesini, Giuseppe

2007-01-01

A holographic process is presented where the object is made of the real image produced by a two-mirror system. Single-step reflection hologram recording is achieved. Details of the process are given, optics concepts are outlined and demonstrative results are presented. (Contains 6 figures and 2 footnotes.)

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks.

PubMed

Farrugia, Kevin J; Fraser, Joanna; Friel, Lauren; Adams, Duncan; Attard-Montalto, Nicola; Deacon, Paul

2015-12-01

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric-Lumicyano 4% atmospheric-BY40) and process B (Lumicyano 4% vacuum-Lumicyano 4% atmospheric-BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower detection rate than the double process with Lumicyano 4%. Furthermore, the double process with conventional cyanoacrylate did not provide any benefit. Scanning electron microscopy was also performed to investigate the morphology of the cyanoacrylate polymer under different conditions. The atmospheric/humidity process appears to be superior to the vacuum process for both the two-step and one-step cyanoacrylate fuming, although the two-step process performed better in comparison to the one-step process under vacuum conditions. Nonetheless, the use of vacuum cyanoacrylate fuming may have certain operational advantages and its use does not adversely affect subsequent cyanoacrylate fuming with atmospheric/humidity conditions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fast dye salts provide fast access to azidoarene synthons in multi-step one-pot tandem click transformations

PubMed Central

Fletcher, James T.; Reilly, Jacquelline E.

2012-01-01

This study examined whether commercially available diazonium salts could be used as efficient aromatic azide precursors in one-pot multi-step click transformations. Seven different diazonium salts, including Fast Red RC, Fast Blue B, Fast Corinth V and Variamine Blue B were surveyed under aqueous click reaction conditions of CuSO4/Na ascorbate catalyst with 1:1 t-BuOH:H2O solvent. Two-step tandem reactions with terminal alkyne and diyne co-reactants led to 1,2,3-triazole products in 66%-88% yields, while three-step tandem reactions with trimethylsilyl-protected alkyne and diyne co-reactants led to 1,2,3-triazole products in 61%-78% yields. PMID:22368306

Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots

NASA Astrophysics Data System (ADS)

WANG, Wei; WANG, Lei; YUN, Chao

2017-03-01

Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle, but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot's base frame and kinematic parameters. The forward kinematics described with respect to the measuring coordinate frame are established based on the product-of-exponential (POE) formula. In the first step the robot's base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot's reference configuration and the base coordinate frame's pose are equivalently transformed to the zero-position errors of the robot's joints. The simplified model of the robot's positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot's 39 kinematic parameters are finished in the second step. It's proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot's base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy.

Modeling the pressure inactivation of Escherichia coli and Salmonella typhimurium in sapote mamey ( Pouteria sapota (Jacq.) H.E. Moore & Stearn) pulp.

PubMed

Saucedo-Reyes, Daniela; Carrillo-Salazar, José A; Román-Padilla, Lizbeth; Saucedo-Veloz, Crescenciano; Reyes-Santamaría, María I; Ramírez-Gilly, Mariana; Tecante, Alberto

2018-03-01

High hydrostatic pressure inactivation kinetics of Escherichia coli ATCC 25922 and Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028 ( S. typhimurium) in a low acid mamey pulp at four pressure levels (300, 350, 400, and 450 MPa), different exposure times (0-8 min), and temperature of 25 ± 2℃ were obtained. Survival curves showed deviations from linearity in the form of a tail (upward concavity). The primary models tested were the Weibull model, the modified Gompertz equation, and the biphasic model. The Weibull model gave the best goodness of fit ( R 2 adj  > 0.956, root mean square error < 0.290) in the modeling and the lowest Akaike information criterion value. Exponential-logistic and exponential decay models, and Bigelow-type and an empirical models for b'( P) and n( P) parameters, respectively, were tested as alternative secondary models. The process validation considered the two- and one-step nonlinear regressions for making predictions of the survival fraction; both regression types provided an adequate goodness of fit and the one-step nonlinear regression clearly reduced fitting errors. The best candidate model according to the Akaike theory information, with better accuracy and more reliable predictions was the Weibull model integrated by the exponential-logistic and exponential decay secondary models as a function of time and pressure (two-step procedure) or incorporated as one equation (one-step procedure). Both mathematical expressions were used to determine the t d parameter, where the desired reductions ( 5D) (considering d = 5 ( t 5 ) as the criterion of 5 Log 10 reduction (5 D)) in both microorganisms are attainable at 400 MPa for 5.487 ± 0.488 or 5.950 ± 0.329 min, respectively, for the one- or two-step nonlinear procedure.

RNA splicing process analysis for identifying antisense oligonucleotide inhibitors with padlock probe-based isothermal amplification.

PubMed

Ren, Xiaojun; Deng, Ruijie; Wang, Lida; Zhang, Kaixiang; Li, Jinghong

2017-08-01

RNA splicing, which mainly involves two transesterification steps, is a fundamental process of gene expression and its abnormal regulation contributes to serious genetic diseases. Antisense oligonucleotides (ASOs) are genetic control tools that can be used to specifically control genes through alteration of the RNA splicing pathway. Despite intensive research, how ASOs or various other factors influence the multiple processes of RNA splicing still remains obscure. This is largely due to an inability to analyze the splicing efficiency of each step in the RNA splicing process with high sensitivity. We addressed this limitation by introducing a padlock probe-based isothermal amplification assay to achieve quantification of the specific products in different splicing steps. With this amplified assay, the roles that ASOs play in RNA splicing inhibition in the first and second steps could be distinguished. We identified that 5'-ASO could block RNA splicing by inhibiting the first step, while 3'-ASO could block RNA splicing by inhibiting the second step. This method provides a versatile tool for assisting efficient ASO design and discovering new splicing modulators and therapeutic drugs.

Two-year Randomized Clinical Trial of Self-etching Adhesives and Selective Enamel Etching.

PubMed

Pena, C E; Rodrigues, J A; Ely, C; Giannini, M; Reis, A F

2016-01-01

The aim of this randomized, controlled prospective clinical trial was to evaluate the clinical effectiveness of restoring noncarious cervical lesions with two self-etching adhesive systems applied with or without selective enamel etching. A one-step self-etching adhesive (Xeno V(+)) and a two-step self-etching system (Clearfil SE Bond) were used. The effectiveness of phosphoric acid selective etching of enamel margins was also evaluated. Fifty-six cavities were restored with each adhesive system and divided into two subgroups (n=28; etch and non-etch). All 112 cavities were restored with the nanohybrid composite Esthet.X HD. The clinical effectiveness of restorations was recorded in terms of retention, marginal integrity, marginal staining, caries recurrence, and postoperative sensitivity after 3, 6, 12, 18, and 24 months (modified United States Public Health Service). The Friedman test detected significant differences only after 18 months for marginal staining in the groups Clearfil SE non-etch (p=0.009) and Xeno V(+) etch (p=0.004). One restoration was lost during the trial (Xeno V(+) etch; p>0.05). Although an increase in marginal staining was recorded for groups Clearfil SE non-etch and Xeno V(+) etch, the clinical effectiveness of restorations was considered acceptable for the single-step and two-step self-etching systems with or without selective enamel etching in this 24-month clinical trial.

Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawai, Kotaro, E-mail: s135016@stn.nagaokaut.ac.jp; Sakamoto, Moritsugu; Noda, Kohei

2016-03-28

A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams.more » These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.« less

Contribution of diagnostic tests for the etiological assessment of uveitis, data from the ULISSE study (Uveitis: Clinical and medicoeconomic evaluation of a standardized strategy of the etiological diagnosis).

PubMed

Grumet, Pierre; Kodjikian, Laurent; de Parisot, Audrey; Errera, Marie-Hélène; Sedira, Neila; Heron, Emmanuel; Pérard, Laurent; Cornut, Pierre-Loïc; Schneider, Christelle; Rivière, Sophie; Ollé, Priscille; Pugnet, Grégory; Cathébras, Pascal; Manoli, Pierre; Bodaghi, Bahram; Saadoun, David; Baillif, Stéphanie; Tieulie, Nathalie; Andre, Marc; Chiambaretta, Frédéric; Bonin, Nicolas; Bielefeld, Philip; Bron, Alain; Mouriaux, Frédéric; Bienvenu, Boris; Vicente, Stéphanie; Bin, Sylvie; Labetoulle, Marc; Broussolle, Christiane; Jamilloux, Yvan; Decullier, Evelyne; Sève, Pascal

2018-04-01

ULISSE is the only study that prospectively assessed the efficiency of a standardized strategy, compared to an open strategy for the etiologic diagnosis of uveitis. Our aim was to evaluate the diagnostic yield of the tests prescribed in the ULISSE study to clarify their relevance. ULISSE is a non-inferiority, prospective, multicenter and cluster randomized study. The standardized strategy is a two-steps strategy: in the first step, common standard tests were performed, and in the second step, tests were guided by the clinical and anatomic type of uveitis. We reported the relevance of the diagnostic tests used in the standardized strategy, as well as the profitability of the tests that were prescribed to more than twenty patients in each group. Based on diagnostic criteria, either an ophthalmologist, or an internist, established the profitability of a test by considering whether the test lead to a diagnosis or not. Among the 676 patients included (standardized 303; open 373), a diagnosis was made for 152 (50.4%) in the standardized group and 203 (54.4%) in the open group. The most common entities were HLA-B27 associated uveitis (22%), spondyloarthritis (11%), sarcoidosis (18%), tuberculosis (10.7%) and herpes virus infections (8.5%). Among the first step's systematic tests, tuberculin skin test was the most contributive investigation (17.1%), followed by chest X-ray (8.4%), C reactive protein and ESR (6.6% and 5.1%), complete blood count (2.2%) and VDRL (2.0%). The second step's most often contributive tests were: HLA B27 (56.3%), chest-CT (30.3%) and angiotensin converting enzyme (ACE) (16.5%). HLA B27 and ACE were significantly more contributive in the standardized group than in the open group. Immunological tests were never contributive. Among the free investigations, or among the investigations guided by clinical or paraclinical findings, the most often contributive tests were: Quantiferon® (24%), electrophoresis of serum protein (7.8%) and sacroiliac imagery (46.4%). Intracellular serologies (1.7%), serum calcium (2.1%) and hepatic tests (3.3%) were exceptionally contributive. Among the third intention tests, labial salivary gland biopsies were contributive in 17.9% of cases, but the profitability of other invasive investigations (anterior chamber tap, vitrectomy, bronchoscopy and lumbar puncture) or specialized imagery (18F-FDG PET, Brain MRI) could not be determined since these test were rarely performed. Only a few diagnostic tests are useful for the etiological assessment of uveitis. They are often cheap, simple, more often guided by the clinical findings, and lead to an etiological diagnosis in most patients. On the other hand, some tests are never or exceptionally contributive, such as immunological tests or intracellular serologies. Further studies are required to evaluate the profitability of third intention imagery and invasive investigations. Copyright © 2018 Elsevier B.V. All rights reserved.

Direct methylation procedure for converting fatty amides to fatty acid methyl esters in feed and digesta samples.

PubMed

Jenkins, T C; Thies, E J; Mosley, E E

2001-05-01

Two direct methylation procedures often used for the analysis of total fatty acids in biological samples were evaluated for their application to samples containing fatty amides. Methylation of 5 mg of oleamide (cis-9-octadecenamide) in a one-step (methanolic HCl for 2 h at 70 degrees C) or a two-step (sodium methoxide for 10 min at 50 degrees C followed by methanolic HCl for 10 min at 80 degrees C) procedure gave 59 and 16% conversions of oleamide to oleic acid, respectively. Oleic acid recovery from oleamide was increased to 100% when the incubation in methanolic HCl was lengthened to 16 h and increased to 103% when the incubation in methoxide was modified to 24 h at 100 degrees C. However, conversion of oleamide to oleic acid in an animal feed sample was incomplete for the modified (24 h) two-step procedure but complete for the modified (16 h) one-step procedure. Unsaturated fatty amides in feed and digesta samples can be converted to fatty acid methyl esters by incubation in methanolic HCl if the time of exposure to the acid catalyst is extended from 2 to 16 h.

Double emulsion formation through hierarchical flow-focusing microchannel

NASA Astrophysics Data System (ADS)

Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

2016-03-01

A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

One-step fabrication of porous GaN crystal membrane and its application in energy storage

NASA Astrophysics Data System (ADS)

Zhang, Lei; Wang, Shouzhi; Shao, Yongliang; Wu, Yongzhong; Sun, Changlong; Huo, Qin; Zhang, Baoguo; Hu, Haixiao; Hao, Xiaopeng

2017-03-01

Single-crystal gallium nitride (GaN) membranes have great potential for a variety of applications. However, fabrication of single-crystalline GaN membranes remains a challenge owing to its chemical inertness and mechanical hardness. This study prepares large-area, free-standing, and single-crystalline porous GaN membranes using a one-step high-temperature annealing technique for the first time. A promising separation model is proposed through a comprehensive study that combines thermodynamic theories analysis and experiments. Porous GaN crystal membrane is processed into supercapacitors, which exhibit stable cycling life, high-rate capability, and ultrahigh power density, to complete proof-of-concept demonstration of new energy storage application. Our results contribute to the study of GaN crystal membranes into a new stage related to the elelctrochemical energy storage application.

Semantic features of 'stepped' versus 'continuous' contours in German intonation.

PubMed

Dombrowski, Ernst

2013-01-01

This study analyses the meaning spaces of German pitch contours using two modes of melodic movement: continuous or in steps of sustained pitch. Both the continuous and stepped movements are represented by a set of five basic patterns, the latter being derived from the former. Thirty-six German native speakers judged the pattern sets on a 12-scale semantic differential. The semantic profiles confirm that stepped contours can be conceived of as stylized intonation, in a formal as well as in a functional sense. On the one hand, continuous (non-stylized) and stepped (stylized) contours are assigned different overall meanings (especially on the scales astonished - commonplace and interested - not interested). On the other hand, listeners organize the two contour sets in a similar fashion, which speaks in favour of parallel pattern inventories of continuous and stepped movement, respectively. However, the meaning space of the stylized patterns is affected by formal restrictions, for instance in the step transformation of continuous rises. © 2014 S. Karger AG, Basel.

Unexpected Reaction Pathway for butyrylcholinesterase-catalyzed inactivation of “hunger hormone” ghrelin

NASA Astrophysics Data System (ADS)

Yao, Jianzhuang; Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

2016-02-01

Extensive computational modeling and simulations have been carried out, in the present study, to uncover the fundamental reaction pathway for butyrylcholinesterase (BChE)-catalyzed hydrolysis of ghrelin, demonstrating that the acylation process of BChE-catalyzed hydrolysis of ghrelin follows an unprecedented single-step reaction pathway and the single-step acylation process is rate-determining. The free energy barrier (18.8 kcal/mol) calculated for the rate-determining step is reasonably close to the experimentally-derived free energy barrier (~19.4 kcal/mol), suggesting that the obtained mechanistic insights are reasonable. The single-step reaction pathway for the acylation is remarkably different from the well-known two-step acylation reaction pathway for numerous ester hydrolysis reactions catalyzed by a serine esterase. This is the first time demonstrating that a single-step reaction pathway is possible for an ester hydrolysis reaction catalyzed by a serine esterase and, therefore, one no longer can simply assume that the acylation process must follow the well-known two-step reaction pathway.

Subgroup Analysis in Burnout: Relations Between Fatigue, Anxiety, and Depression

PubMed Central

van Dam, Arno

2016-01-01

Several authors have suggested that burned out patients do not form a homogeneous group and that subgroups should be considered. The identification of these subgroups may contribute to a better understanding of the burnout construct and lead to more specific therapeutic interventions. Subgroup analysis may also help clarify whether burnout is a distinct entity and whether subgroups of burnout overlap with other disorders such as depression and chronic fatigue syndrome. In a group of 113 clinically diagnosed burned out patients, levels of fatigue, depression, and anxiety were assessed. In order to identify possible subgroups, we performed a two-step cluster analysis. The analysis revealed two clusters that differed from one another in terms of symptom severity on the three aforementioned measures. Depression appeared to be the strongest predictor of group membership. These results are considered in the light of the scientific debate on whether burnout can be distinguished from depression and whether burnout subtyping is useful. Finally, implications for clinical practice and future research are discussed. PMID:26869983

The chaotic set and the cross section for chaotic scattering in three degrees of freedom

NASA Astrophysics Data System (ADS)

Jung, C.; Merlo, O.; Seligman, T. H.; Zapfe, W. P. K.

2010-10-01

This article treats chaotic scattering with three degrees of freedom, where one of them is open and the other two are closed, as a first step towards a more general understanding of chaotic scattering in higher dimensions. Despite the strong restrictions, it breaks the essential simplicity implicit in any two-dimensional time-independent scattering problem. Introducing the third degree of freedom by breaking a continuous symmetry, we first explore the topological structure of the homoclinic/heteroclinic tangle and the structures in the scattering functions. Then we work out the implications of these structures for the doubly differential cross section. The most prominent structures in the cross section are rainbow singularities. They form a fractal pattern that reflects the fractal structure of the chaotic invariant set. This allows us to determine structures in the cross section from the invariant set and, conversely, to obtain information about the topology of the invariant set from the cross section. The latter is a contribution to the inverse scattering problem for chaotic systems.

Two-tier Haddon matrix approach to fault analysis of accidents and cybernetic search for relationship to effect operational control: a case study at a large construction site.

PubMed

Mazumdar, Atmadeep; Sen, Krishna Nirmalya; Lahiri, Balendra Nath

2007-01-01

The Haddon matrix is a potential tool for recognizing hazards in any operating engineering system. This paper presents a case study of operational hazards at a large construction site. The fish bone structure helps to visualize and relate the chain of events, which led to the failure of the system. The two-tier Haddon matrix approach helps to analyze the problem and subsequently prescribes preventive steps. The cybernetic approach has been undertaken to establish the relationship among event variables and to identify the ones with most potential. Those event variables in this case study, based on the cybernetic concepts like control responsiveness and controllability salience, are (a) uncontrolled swing of sheet contributing to energy, (b) slippage of sheet from anchor, (c) restricted longitudinal and transverse swing or rotation about the suspension, (d) guilt or uncertainty of the crane driver, (e) safe working practices and environment.

Use of Curricular and Extracurricular Assessments to Predict Performance on the United States Medical Licensing Examination (USMLE) Step 1: A Multi-Year Study

ERIC Educational Resources Information Center

Gandy, Robyn A.; Herial, Nabeel A.; Khuder, Sadik A.; Metting, Patricia J.

2008-01-01

This paper studies student performance predictions based on the United States Medical Licensure Exam (USMLE) Step 1. Subjects were second-year medical students from academic years of 2002 through 2006 (n = 711). Three measures of basic science knowledge (two curricular and one extracurricular) were evaluated as predictors of USMLE Step 1 scores.…

A two-step initial mass function:. Consequences of clustered star formation for binary properties

NASA Astrophysics Data System (ADS)

Durisen, R. H.; Sterzik, M. F.; Pickett, B. K.

2001-06-01

If stars originate in transient bound clusters of moderate size, these clusters will decay due to dynamic interactions in which a hard binary forms and ejects most or all the other stars. When the cluster members are chosen at random from a reasonable initial mass function (IMF), the resulting binary characteristics do not match current observations. We find a significant improvement in the trends of binary properties from this scenario when an additional constraint is taken into account, namely that there is a distribution of total cluster masses set by the masses of the cloud cores from which the clusters form. Two distinct steps then determine final stellar masses - the choice of a cluster mass and the formation of the individual stars. We refer to this as a ``two-step'' IMF. Simple statistical arguments are used in this paper to show that a two-step IMF, combined with typical results from dynamic few-body system decay, tends to give better agreement between computed binary characteristics and observations than a one-step mass selection process.

Effect of using two-step thermal annealing with different ambient gas on Mg activation and crystalline quality in GaN

NASA Astrophysics Data System (ADS)

Azimah, E.; Zainal, N.; Shuhaimi, A.; Hassan, Z.

2015-06-01

Two-step thermal annealing with different ambient gas was proposed to improve the activation of Mg doping in MOCVD-GaN films; (1) with nitrogen at the first step and followed by oxygen (N2/O2) and (2) with O2 and then by N2 (O2/N2). For comparison, two samples annealed in one-step thermal annealing using air and N2, respectively were also prepared. From Hall-effect measurement, the two-step annealing with the use of O2/N2 treatment was found to give the highest hole concentration at to 5.5 × 1017 cm-3. On the other hand, Raman spectroscopy and XRD measurements revealed that the O2/N2 annealed sample exhibited the smallest compressive strain and FWHM (full width at high maximum) compared to others. Hence, the annealing with O2/N2 is proposed to be the most promising technique that not only to increase the hole concentration effectively but also to improve the crystalline quality of the samples.

One hundred years of lessons about the impact of war on mental health; two steps forward, one step back.

PubMed

McFarlane, Alexander C

2015-08-01

This paper outlines the substantial stigmatization of soldiers who suffered psychiatric disorders during World War I, and how there was little acceptance of the enduring impact of prolonged combat exposure once the war ended. Recent decades of research highlight the delayed impact of combat exposure and its long-term neurobiological consequences. © The Royal Australian and New Zealand College of Psychiatrists 2015.

Be an NIH Reviewer: Contribute to Multidisciplinary Research.

PubMed

Jenkins, Melinda L

2018-03-01

One of the best ways to contribute to multidisciplinary research and to improve your own knowledge of the review process at the National Institutes of Health (NIH) is to serve as a peer reviewer for research, traineeship, and small business innovation research proposals. Proactive targeted outreach to Scientific Review Officers (SROs) at NIH will increase your chances to become a reviewer. Reviewers with nursing expertise are especially welcome as multidisciplinary research is becoming more prevalent. Steps to identify a likely study section, contact the correct SRO, and review responsibly are described in this article, written by an experienced NIH review officer.

Two-step growth of two-dimensional WSe 2/MoSe 2 heterostructures

DOE PAGES

Gong, Yongji; Lei, Sidong; Lou, Jun; ...

2015-08-03

Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe 2 was synthesized first and followed by an epitaxial growth of WSe 2 on the edge and on the top surface of MoSe 2. Compared to previously reported one-stepmore » growth methods, this two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 μm) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe 2/MoSe 2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe 2/WSe 2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe 2/MoSe 2 bilayer and the exposed MoSe 2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. As a result, a photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting.« less

Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks.

PubMed

Elmitwalli, T A; Sayed, S; Groendijk, L; van Lier, J; Zeeman, G; Lettinga, G

2003-01-01

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13 degrees C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13 degrees C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

Performance of a new one-step multi-mode adhesive on etched vs non-etched enamel on bond strength and interfacial morphology.

PubMed

de Goes, Mario Fernando; Shinohara, Mirela Sanae; Freitas, Marcela Santiago

2014-06-01

To compare microtensile bond strength (μTBS) and interfacial morphology of a new one-step multimode adhesive with a two-step self-etching adhesive and two etch-and-rinse adhesives systems on enamel. Thirty human third molars were sectioned to obtain two enamel fragments. For μTBS, 48 enamel surfaces were ground using 600-grit SiC paper and randomly assigned into 6 groups (n = 8): nonetched Scotchbond Universal [SBU]; etched SBU [SBU-et]; non-etched Clearfil SE Bond [CSE]; etched CSE [CSE-et]; Scotchbond Multi-PURPOSE [SBMP]; Excite [EX]. The etched specimens were conditioned with 37% phosphoric acid for 30 s, each adhesive system was applied according to manufacturers' instructions, and composite resin blocks (Filtek Supreme Plus, 3M ESPE) were incrementally built up. Specimens were sectioned into beams with a cross-sectional area of 0.8-mm2 and tested under tension (1 mm/min). The data were analyzed with oneway ANOVA and Fisher's PLSD (α = 0.05). For interface analysis, two samples from each group were embedded in epoxy resin, polished, and then observed using scanning electron microscopy (SEM). The μTBS values (in MPa) and the standard deviations were: SBU = 27.4 (8.5); SBU-et = 33.6 (9.3); CSE = 28.5 (8.3); CSE-et = 34.2 (9.0); SBMP = 30.4 (11.0); EX = 23.3 (8.2). CSE-et and SBU-et presented the highest bond strength values, followed by SBMP, CSE, and SBU which did not differ significantly from each other. EX showed the statistically significantly lowest bond strength values. SEM images of interfaces from etched samples showed long adhesive-resin tags penetrating into demineralized enamel. Preliminary etching of enamel significantly increased bond strength for the new one-step multimode adhesive SBU and two-step self-etching adhesive CSE.

A novel cinnamyl alcohol dehydrogenase (CAD)-like reductase contributes to the structural diversity of monoterpenoid indole alkaloids in Rauvolfia.

PubMed

Geissler, Marcus; Burghard, Marie; Volk, Jascha; Staniek, Agata; Warzecha, Heribert

2016-03-01

Based on findings described herein, we contend that the reduction of vomilenine en route to antiarrhythmic ajmaline in planta might proceed via an alternative, novel sequence of biosynthetic steps. In the genus Rauvolfia, monoterpenoid indole alkaloids (MIAs) are formed via complex biosynthetic sequences. Despite the wealth of information about the biochemistry and molecular genetics underlying these processes, many reaction steps involving oxygenases and oxidoreductases are still elusive. Here, we describe molecular cloning and characterization of three cinnamyl alcohol dehydrogenase (CAD)-like reductases from Rauvolfia serpentina cell culture and R. tetraphylla roots. Functional analysis of the recombinant proteins, with a set of MIAs as potential substrates, led to identification of one of the enzymes as a CAD, putatively involved in lignin formation. The two remaining reductases comprise isoenzymes derived from orthologous genes of the investigated alternative Rauvolfia species. Their catalytic activity consists of specific conversion of vomilenine to 19,20-dihydrovomilenine, thus proving their exclusive involvement in MIA biosynthesis. The obtained data suggest the existence of a previously unknown bypass in the biosynthetic route to ajmaline further expanding structural diversity within the MIA family of specialized plant metabolites.

Exploring patient satisfaction predictors in relation to a theoretical model.

PubMed

Grøndahl, Vigdis Abrahamsen; Hall-Lord, Marie Louise; Karlsson, Ingela; Appelgren, Jari; Wilde-Larsson, Bodil

2013-01-01

The aim is to describe patients' care quality perceptions and satisfaction and to explore potential patient satisfaction predictors as person-related conditions, external objective care conditions and patients' perception of actual care received ("PR") in relation to a theoretical model. A cross-sectional design was used. Data were collected using one questionnaire combining questions from four instruments: Quality from patients' perspective; Sense of coherence; Big five personality trait; and Emotional stress reaction questionnaire (ESRQ), together with questions from previous research. In total, 528 patients (83.7 per cent response rate) from eight medical, three surgical and one medical/surgical ward in five Norwegian hospitals participated. Answers from 373 respondents with complete ESRQ questionnaires were analysed. Sequential multiple regression analysis with ESRQ as dependent variable was run in three steps: person-related conditions, external objective care conditions, and PR (p < 0.05). Step 1 (person-related conditions) explained 51.7 per cent of the ESRQ variance. Step 2 (external objective care conditions) explained an additional 2.4 per cent. Step 3 (PR) gave no significant additional explanation (0.05 per cent). Steps 1 and 2 contributed statistical significance to the model. Patients rated both quality-of-care and satisfaction highly. The paper shows that the theoretical model using an emotion-oriented approach to assess patient satisfaction can explain 54 per cent of patient satisfaction in a statistically significant manner.

Sensor feature fusion for detecting buried objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, G.A.; Sengupta, S.K.; Sherwood, R.J.

1993-04-01

Given multiple registered images of the earth`s surface from dual-band sensors, our system fuses information from the sensors to reduce the effects of clutter and improve the ability to detect buried or surface target sites. The sensor suite currently includes two sensors (5 micron and 10 micron wavelengths) and one ground penetrating radar (GPR) of the wide-band pulsed synthetic aperture type. We use a supervised teaming pattern recognition approach to detect metal and plastic land mines buried in soil. The overall process consists of four main parts: Preprocessing, feature extraction, feature selection, and classification. These parts are used in amore » two step process to classify a subimage. Thee first step, referred to as feature selection, determines the features of sub-images which result in the greatest separability among the classes. The second step, image labeling, uses the selected features and the decisions from a pattern classifier to label the regions in the image which are likely to correspond to buried mines. We extract features from the images, and use feature selection algorithms to select only the most important features according to their contribution to correct detections. This allows us to save computational complexity and determine which of the sensors add value to the detection system. The most important features from the various sensors are fused using supervised teaming pattern classifiers (including neural networks). We present results of experiments to detect buried land mines from real data, and evaluate the usefulness of fusing feature information from multiple sensor types, including dual-band infrared and ground penetrating radar. The novelty of the work lies mostly in the combination of the algorithms and their application to the very important and currently unsolved operational problem of detecting buried land mines from an airborne standoff platform.« less

Examining racial and ethnic minority differences among YMSM during recruitment for an online HIV prevention intervention study.

PubMed

Du Bois, Steve N; Johnson, Sarah E; Mustanski, Brian

2012-08-01

HIV disproportionately affects racial and ethnic minority young men who have sex with men (YMSM). HIV prevention research does not include these YMSM commensurate to their HIV burden. We examined racial and ethnic differences during a unique three-step recruitment process for an online, YMSM HIV prevention intervention study (N = 660). Step one was completed in-person; steps two and three online. Fewer Black and Latino YMSM completed step two-initiating online participation-than White YMSM. Internet use frequency accounted for the Latino versus White difference in initiating online participation, but not the Black versus White difference. Future online HIV prevention interventions recruiting diverse YMSM should focus on initiating online engagement among Black participants.

Examining Racial and Ethnic Minority Differences among YMSM during Recruitment for an Online HIV Prevention Intervention Study

PubMed Central

Du Bois, Steve N.; Johnson, Sarah E.; Mustanski, Brian

2011-01-01

HIV disproportionately affects racial and ethnic minority young men who have sex with men (YMSM). HIV prevention research does not include these YMSM commensurate to their HIV burden. We examined racial and ethnic differences during a unique three-step recruitment process for an online, YMSM HIV prevention intervention study (N=660). Step one was completed in-person; steps two and three online. Fewer Black and Latino YMSM completed step two – initiating online participation – than White YMSM. Internet use frequency accounted for the Latino vs. White difference in initiating online participation, but not the Black vs. White difference. Future online HIV prevention interventions recruiting diverse YMSM should focus on initiating online engagement among Black participants. PMID:21986869

Balancing Chemical Equations: The Role of Developmental Level and Mental Capacity.

ERIC Educational Resources Information Center

Niaz, Mansoor; Lawson, Anton E.

1985-01-01

Tested two hypotheses: (1) formal reasoning is required to balance simple one-step equations; and (2) formal reasoning plus sufficient mental capacity are required to balance many-step equations. Independent variables included intellectual development, mental capacity, and degree of field dependence/independence. With 25 subjects, significance was…

Building America's Industrial Revolution: The Boott Cotton Mills of Lowell, Massachusetts. Teaching with Historic Places.

ERIC Educational Resources Information Center

Stowell, Stephen

1995-01-01

Presents a high school unit about the U.S. Industrial Revolution featuring the Boott Cotton Mills of Lowell, Massachusetts. Includes student objectives, step-by-step instructional procedures, and discussion questions. Provides two maps, five illustrations, one photograph, and three student readings. (ACM)

Corruption and Educational Outcomes: Two Steps Forward, One Step Back

ERIC Educational Resources Information Center

Huang, Francis Lim

2008-01-01

Corruption is a problem that continues to plague developed and developing countries worldwide. Previous studies have explored the negative implications of corruption on several aspects of human development, but, despite its serious and long-lasting consequences, the impact of corruption on educational outcomes has started to receive attention only…

Comparison of analysis methods for airway quantification

NASA Astrophysics Data System (ADS)

Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.

2012-03-01

Diseased airways have been known for several years as a possible contributing factor to airflow limitation in Chronic Obstructive Pulmonary Diseases (COPD). Quantification of disease severity through the evaluation of airway dimensions - wall thickness and lumen diameter - has gained increased attention, thanks to the availability of multi-slice computed tomography (CT). Novel approaches have focused on automated methods of measurement as a faster and more objective means that the visual assessment routinely employed in the clinic. Since the Full-Width Half-Maximum (FWHM) method of airway measurement was introduced two decades ago [1], several new techniques for quantifying airways have been detailed in the literature, but no approach has truly become a standard for such analysis. Our own research group has presented two alternative approaches for determining airway dimensions, one involving a minimum path and the other active contours [2, 3]. With an increasing number of techniques dedicated to the same goal, we decided to take a step back and analyze the differences of these methods. We consequently put to the test our two methods of analysis and the FWHM approach. We first measured a set of 5 airways from a phantom of known dimensions. Then we compared measurements from the three methods to those of two independent readers, performed on 35 airways in 5 patients. We elaborate on the differences of each approach and suggest conclusions on which could be defined as the best one.

Tracking Steps on Apple Watch at Different Walking Speeds.

PubMed

Veerabhadrappa, Praveen; Moran, Matthew Duffy; Renninger, Mitchell D; Rhudy, Matthew B; Dreisbach, Scott B; Gift, Kristin M

2018-04-09

QUESTION: How accurate are the step counts obtained from Apple Watch? In this validation study, video steps vs. Apple Watch steps (mean ± SD) were 2965 ± 144 vs. 2964 ± 145 steps; P < 0.001. Lin's concordance correlation coefficient showed a strong correlation (r = 0.96; P < 0.001) between the two measurements. There was a total error of 0.034% (1.07 steps) for the Apple Watch steps when compared with the manual counts obtained from video recordings. Our study is one of the initial studies to objectively validate the accuracy of the step counts obtained from Apple watch at different walking speeds. Apple Watch tested to be an extremely accurate device for measuring daily step counts for adults.

Simplified Two-Time Step Method for Calculating Combustion and Emission Rates of Jet-A and Methane Fuel With and Without Water Injection

NASA Technical Reports Server (NTRS)

Molnar, Melissa; Marek, C. John

2005-01-01

A simplified kinetic scheme for Jet-A, and methane fuels with water injection was developed to be used in numerical combustion codes, such as the National Combustor Code (NCC) or even simple FORTRAN codes. The two time step method is either an initial time averaged value (step one) or an instantaneous value (step two). The switch is based on the water concentration in moles/cc of 1x10(exp -20). The results presented here results in a correlation that gives the chemical kinetic time as two separate functions. This two time step method is used as opposed to a one step time averaged method previously developed to determine the chemical kinetic time with increased accuracy. The first time averaged step is used at the initial times for smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, initial water to fuel mass ratio, temperature, and pressure. The second instantaneous step, to be used with higher water concentrations, gives the chemical kinetic time as a function of instantaneous fuel and water mole concentration, pressure and temperature (T4). The simple correlations would then be compared to the turbulent mixing times to determine the limiting rates of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. Chemical kinetic time equations for fuel, carbon monoxide and NOx are obtained for Jet-A fuel and methane with and without water injection to water mass loadings of 2/1 water to fuel. A similar correlation was also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium concentrations of carbon monoxide and nitrogen oxide as functions of overall equivalence ratio, water to fuel mass ratio, pressure and temperature (T3). The temperature of the gas entering the turbine (T4) was also correlated as a function of the initial combustor temperature (T3), equivalence ratio, water to fuel mass ratio, and pressure.

Numerical characterisation of one-step and three-step solar air heating collectors used for cocoa bean solar drying.

PubMed

Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel; La Madrid, Raúl

2017-12-01

In the northern coastal and jungle areas of Peru, cocoa beans are dried using artisan methods, such as direct exposure to sunlight. This traditional process is time intensive, leading to a reduction in productivity and, therefore, delays in delivery times. The present study was intended to numerically characterise the thermal behaviour of three configurations of solar air heating collectors in order to determine which demonstrated the best thermal performance under several controlled operating conditions. For this purpose, a computational fluid dynamics model was developed to describe the simultaneous convective and radiative heat transfer phenomena under several operation conditions. The constructed computational fluid dynamics model was firstly validated through comparison with the data measurements of a one-step solar air heating collector. We then simulated two further three-step solar air heating collectors in order to identify which demonstrated the best thermal performance in terms of outlet air temperature and thermal efficiency. The numerical results show that under the same solar irradiation area of exposition and operating conditions, the three-step solar air heating collector with the collector plate mounted between the second and third channels was 67% more thermally efficient compared to the one-step solar air heating collector. This is because the air exposition with the surface of the collector plate for the three-step solar air heating collector former device was twice than the one-step solar air heating collector. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lessons learned in stepped chute research

USDA-ARS?s Scientific Manuscript database

Early research on stepped chutes focused on steep gravity style stepped chutes. Today, the research trend has shifted to stepped chutes applied to more moderate slopes like those for aging embankment dams. Research contributions have been made on hydraulic properties of stepped chutes including ai...

Perinatal research and its support. Corporate contributions at McGill University.

PubMed

Little, B; Hamilton, E; Quillen, E; Watkin, K; Nuwayhid, B; Stripp, B

1994-05-01

Three technologic projects with potentially patentable end results are slowly evolving in the Department of Obstetrics and Gynecology, McGill University and Royal Victoria Hospital. A tax shelter infusion of a significant amount of venture capital developed opportunities for all three projects over two years. The three projects--fetal heart rate tracing analysis related to fetal outcome, a distributed and intelligent data acquisition system and selected ultrasonic three dimensional imaging--were advanced considerably, and their results are expressed in outline. The effects of such infusions of business support into an environment of sparse research grant support have been extremely encouraging to the investigators, but the department, with its obligations of ongoing research, teaching and patient care, must develop the next steps with care, although one of the projects has been extended by an interested corporation.

One-step trinary signed-digit arithmetic using an efficient encoding scheme

NASA Astrophysics Data System (ADS)

Salim, W. Y.; Fyath, R. S.; Ali, S. A.; Alam, Mohammad S.

2000-11-01

The trinary signed-digit (TSD) number system is of interest for ultra fast optoelectronic computing systems since it permits parallel carry-free addition and borrow-free subtraction of two arbitrary length numbers in constant time. In this paper, a simple coding scheme is proposed to encode the decimal number directly into the TSD form. The coding scheme enables one to perform parallel one-step TSD arithmetic operation. The proposed coding scheme uses only a 5-combination coding table instead of the 625-combination table reported recently for recoded TSD arithmetic technique.

Type 1 Does The Two-Step: Type 1 Secretion Substrates With A Functional Periplasmic Intermediate.

PubMed

Smith, Timothy J; Sondermann, Holger; O'Toole, George A

2018-06-04

Bacteria have evolved several secretion strategies for polling and responding to environmental flux and insult. Of these, the type 1 secretion system (T1SS) is known to secrete an array of biologically diverse proteins - from small < 10 kDa bacteriocins to gigantic adhesins with a mass over 1 MDa. For the last several decades T1SS have been characterized as a one-step translocation strategy whereby the secreted substrate is transported directly into the extracellular environment from the cytoplasm with no periplasmic intermediate. Recent phylogenetic, biochemical, and genetic evidence point to a distinct sub-group of T1SS machinery linked with a bacterial transglutaminase-like cysteine proteinase (BTLCP), which uses a two-step secretion mechanism. BTLCP-linked T1SS transport a class of repeats-in-toxin (RTX) adhesins that are critical for biofilm formation. The prototype of this RTX adhesin group, LapA of Pseudomonas fluorescens Pf0-1, uses a novel N-terminal retention module to anchor the adhesin at the cell surface as a secretion intermediate threaded through the outer membrane-localized, TolC-like protein LapE. This secretion intermediate is post-translationally cleaved by the BTLCP family LapG protein to release LapA from its cognate T1SS pore. Thus, secretion of LapA and related RTX adhesins into the extracellular environment appears to be a T1SS-mediated, two-step process that involves a periplasmic intermediate. In this review, we contrast the T1SS machinery and substrates of the BLTCP-linked two-step secretion process with those of the classical one-step T1SS to better understand the newly recognized and expanded role of this secretion machinery. Copyright © 2018 American Society for Microbiology.

An infinite-order two-component relativistic Hamiltonian by a simple one-step transformation.

PubMed

Ilias, Miroslav; Saue, Trond

2007-02-14

The authors report the implementation of a simple one-step method for obtaining an infinite-order two-component (IOTC) relativistic Hamiltonian using matrix algebra. They apply the IOTC Hamiltonian to calculations of excitation and ionization energies as well as electric and magnetic properties of the radon atom. The results are compared to corresponding calculations using identical basis sets and based on the four-component Dirac-Coulomb Hamiltonian as well as Douglas-Kroll-Hess and zeroth-order regular approximation Hamiltonians, all implemented in the DIRAC program package, thus allowing a comprehensive comparison of relativistic Hamiltonians within the finite basis approximation.

Two-step entanglement concentration for arbitrary electronic cluster state

NASA Astrophysics Data System (ADS)

Zhao, Sheng-Yang; Liu, Jiong; Zhou, Lan; Sheng, Yu-Bo

2013-12-01

We present an efficient protocol for concentrating an arbitrary four-electron less-entangled cluster state into a maximally entangled cluster state. As a two-step entanglement concentration protocol (ECP), it only needs one pair of less-entangled cluster state, which makes this ECP more economical. With the help of electronic polarization beam splitter (PBS) and the charge detection, the whole concentration process is essentially the quantum nondemolition (QND) measurement. Therefore, the concentrated maximally entangled state can be remained for further application. Moreover, the discarded terms in some traditional ECPs can be reused to obtain a high success probability. It is feasible and useful in current one-way quantum computation.

Seed maturation associated transcriptional programs and regulatory networks underlying genotypic difference in seed dormancy and size/weight in wheat (Triticum aestivum L.).

PubMed

Yamasaki, Yuji; Gao, Feng; Jordan, Mark C; Ayele, Belay T

2017-09-16

Maturation forms one of the critical seed developmental phases and it is characterized mainly by programmed cell death, dormancy and desiccation, however, the transcriptional programs and regulatory networks underlying acquisition of dormancy and deposition of storage reserves during the maturation phase of seed development are poorly understood in wheat. The present study performed comparative spatiotemporal transcriptomic analysis of seed maturation in two wheat genotypes with contrasting seed weight/size and dormancy phenotype. The embryo and endosperm tissues of maturing seeds appeared to exhibit genotype-specific temporal shifts in gene expression profile that might contribute to the seed phenotypic variations. Functional annotations of gene clusters suggest that the two tissues exhibit distinct but genotypically overlapping molecular functions. Motif enrichment predicts genotypically distinct abscisic acid (ABA) and gibberellin (GA) regulated transcriptional networks contribute to the contrasting seed weight/size and dormancy phenotypes between the two genotypes. While other ABA responsive element (ABRE) motifs are enriched in both genotypes, the prevalence of G-box-like motif specifically in tissues of the dormant genotype suggests distinct ABA mediated transcriptional mechanisms control the establishment of dormancy during seed maturation. In agreement with this, the bZIP transcription factors that co-express with ABRE enriched embryonic genes differ with genotype. The enrichment of SITEIIATCYTC motif specifically in embryo clusters of maturing seeds irrespective of genotype predicts a tissue specific role for the respective TCP transcription factors with no or minimal contribution to the variations in seed dormancy. The results of this study advance our understanding of the seed maturation associated molecular mechanisms underlying variation in dormancy and weight/size in wheat seeds, which is a critical step towards the designing of molecular strategies for enhancing seed yield and quality.

Identifying pleiotropic genes in genome-wide association studies from related subjects using the linear mixed model and Fisher combination function.

PubMed

Yang, James J; Williams, L Keoki; Buu, Anne

2017-08-24

A multivariate genome-wide association test is proposed for analyzing data on multivariate quantitative phenotypes collected from related subjects. The proposed method is a two-step approach. The first step models the association between the genotype and marginal phenotype using a linear mixed model. The second step uses the correlation between residuals of the linear mixed model to estimate the null distribution of the Fisher combination test statistic. The simulation results show that the proposed method controls the type I error rate and is more powerful than the marginal tests across different population structures (admixed or non-admixed) and relatedness (related or independent). The statistical analysis on the database of the Study of Addiction: Genetics and Environment (SAGE) demonstrates that applying the multivariate association test may facilitate identification of the pleiotropic genes contributing to the risk for alcohol dependence commonly expressed by four correlated phenotypes. This study proposes a multivariate method for identifying pleiotropic genes while adjusting for cryptic relatedness and population structure between subjects. The two-step approach is not only powerful but also computationally efficient even when the number of subjects and the number of phenotypes are both very large.

Bonding durability of dual-curing composite core material with different self-etching adhesive systems in a model complete vertical root fracture reconstruction.

PubMed

Waidyasekera, Kanchana; Nikaido, Toru; Weerasinghe, Dinesh; Nurrohman, Hamid; Tagami, Junji

2012-04-01

This study evaluated a dual-curing composite along with different dentin adhesive systems for 1 year under water storage, as a new bonding method of root fragments in complete vertical root fracture. Bovine root fragments were bonded with the dual-curing resin composite Clearfil DC Core Automix (DCA) and one of three adhesive systems: two-step self-etching adhesive Clearfil SE Bond (SE), one-step self-etching adhesive Tokuyama Bond Force (BF), one-step dual-curing self-etching adhesive Clearfil DC Bond (DC). Microtensile bond strength (µTBS)/ultimate tensile bond strength (UTS), FE-SEM ultramorphology of fracture modes, and adhesive dentin interface were observed after water storage for periods of up to one year. The data were analyzed with two-way ANOVA. µTBS was influenced by "dentin adhesive system" (F = 324.455, p < 0.001) and "length of water storage" (F = 8.470, p < 0.001). SE yielded significantly higher µTBS, regardless of storage period (p < 0.05) and maintained the initial µTBS without a significant change after 1 year of water storage (p > 0.05). From 24 h to 1 month, BF showed significantly higher bond strength than DC. UTS of DCA was influenced only by the curing mode of the material (F = 5.051, p = 0.027), but not by the length of water storage (F = 0.053, p > 0.05). Two-step self-etching adhesive systems and dual-curing composite core material can be considered as a suitable bonding method for complete root fractures.

Brief Report: What Drives Parental Concerns about Their 18-Month-Olds at Familial Risk for Autism Spectrum Disorder?

ERIC Educational Resources Information Center

Karp, Elizabeth A.; Ibañez, Lisa V.; Warren, Zachary; Stone, Wendy L.

2017-01-01

Parent-reported developmental concerns can be a first step toward further screening and intervention for children at risk for ASD. However, little is known about the extent to which parental well-being and child behavior contribute to parental concerns, especially in families who already have one child with ASD. This study included 54 parents and…

Purification of anti-Japanese encephalitis virus monoclonal antibody by ceramic hydroxyapatite chromatography without proteins A and G.

PubMed

Saito, Maiko; Kurosawa, Yae; Okuyama, Tsuneo

2012-02-01

Antibody purification using proteins A and G has been a standard method for research and industrial processes. The conventional method, however, includes a three-step process, including buffer exchange, before chromatography. In addition, proteins A and G require low pH elution, which causes antibody aggregation and inactivates the antibody's immunity. This report proposes a two-step method using hydroxyapatite chromatography and membrane filtration, without proteins A and G. This novel method shortens the running time to one-third the conventional method for each cycle. Using our two-step method, 90.2% of the monoclonal antibodies purified were recovered in the elution fraction, the purity achieved was >90%, and most of the antigen-specific activity was retained. This report suggests that the two-step method using hydroxyapatite chromatography and membrane filtration should be considered as an alternative to purification using proteins A and G.

Superhydrophobic aluminum alloy surfaces by a novel one-step process.

PubMed

Saleema, N; Sarkar, D K; Paynter, R W; Chen, X-G

2010-09-01

A simple one-step process has been developed to render aluminum alloy surfaces superhydrophobic by immersing the aluminum alloy substrates in a solution containing NaOH and fluoroalkyl-silane (FAS-17) molecules. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements have been performed to characterize the morphological features, chemical composition and superhydrophobicity of the surfaces. The resulting surfaces provided a water contact angle as high as ∼162° and a contact angle hysteresis as low as ∼4°. The study indicates that it is possible to fabricate superhydrophobic aluminum surfaces easily and effectively without involving the traditional two-step processes.

Smear layer-deproteinizing improves bonding of one-step self-etch adhesives to dentin.

PubMed

Thanatvarakorn, Ornnicha; Prasansuttiporn, Taweesak; Thittaweerat, Suppason; Foxton, Richard M; Ichinose, Shizuko; Tagami, Junji; Hosaka, Keiichi; Nakajima, Masatoshi

2018-03-01

Smear layer deproteinizing was proved to reduce the organic phase of smear layer covered on dentin surface. It was shown to eliminate hybridized smear layer and nanoleakage expression in resin-dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives. Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond™ Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human dentin surfaces with standardized smear layer were prepared. Smear layer deproteinizing was carried out by the application of 50ppm hypochlorous acid (HOCl) on dentin surface for 15s followed by Accel ® (p-toluenesulfinic acid salt) for 5s prior to adhesive application. No surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey's post-hoc test and t-test at the significant level of 0.05. Smear layer deproteinizing significantly improved μTBS of SE, SU, and BB (p<0.001). Hybridized smear layer observed in control groups of SE, BB, and BF, and reticular nanoleakage presented throughout the hybridized complex in control groups of BB and BF were eliminated upon the smear layer deproteinizing. Smear layer deproteinizing by HOCl and Accel ® application could enhance the quality of dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin-dentin bonding interface. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Assessing Student Behaviors and Motivation for Actively Learning Biology

NASA Astrophysics Data System (ADS)

Moore, Michael Edward

Vision and Change states that one of the major changes in the way we design biology courses should be a switch in approach from teacher-centered learning to student-centered learning and identifies active learning as a recommended methods. Studies show performance benefits for students taking courses that use active learning. What is unknown is why active learning is such an effective instructional tool and the limits of this instructional method’s ability to influence performance. This dissertation builds a case in three steps for why active learning is an effective instructional tool. In step one, I assessed the influence of different types of active learning (clickers, group activities, and whole class discussions) on student engagement behavior in one semester of two different introductory biology courses and found that active learning positively influenced student engagement behavior significantly more than lecture. For step two, I examined over four semesters whether student engagement behavior was a predictor of performance and found participation (engagement behavior) in the online (video watching) and in-class course activities (clicker participation) that I measure were significant predictors of performance. In the third, I assessed whether certain active learning satisfied the psychological needs that lead to students’ intrinsic motivation to participate in those activities when compared over two semesters and across two different institutions of higher learning. Findings from this last step show us that student’s perceptions of autonomy, competency, and relatedness in doing various types of active learning are significantly higher than lecture and consistent across two institutions of higher learning. Lastly, I tie everything together, discuss implications of the research, and address future directions for research on biology student motivation and behavior.

Spallation reactions: A successful interplay between modeling and applications

NASA Astrophysics Data System (ADS)

David, J.-C.

2015-06-01

The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200MeV deuterons and 400MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. In the same year, R. Serber described the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a workshop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improvements achieved since Serber. Particle transport codes can then rely on such spallation models to treat the reactions between a light particle and an atomic nucleus with energies spanning from few tens of MeV up to some GeV. An overview of the spallation reactions modeling is presented in order to point out the incomparable contribution of models based on basic physics to numerous applications where such reactions occur. Validations or benchmarks, which are necessary steps in the improvement process, are also addressed, as well as the potential future domains of development. Spallation reactions modeling is a representative case of continuous studies aiming at understanding a reaction mechanism and which end up in a powerful tool.

Analysis of walking improvement with dynamic shoe insoles, using two accelerometers

NASA Astrophysics Data System (ADS)

Tsuruoka, Yuriko; Tamura, Yoshiyasu; Shibasaki, Ryosuke; Tsuruoka, Masako

2005-07-01

The orthopedics at the rehabilitation hospital found that disorders caused by sports injuries to the feet or caused by lower-back are improved by wearing dynamic shoe insoles, these improve walking balance and stability. However, the relationship of the lower-back and knees and the rate of increase in stability were not quantitatively analyzed. In this study, using two accelerometers, we quantitatively analyzed the reciprocal spatiotemporal contributions between the lower-back and knee of patients with left lower-back pain by means of Relative Power Contribution Analysis. When the insoles were worn, the contribution of the left and right knee relative to the left lower-back pain was up to 26% ( p<0.05) greater than without the insoles. Comparing patients with and without insoles, we found that the variance in the step response analysis of the left and right knee decreased by up to 67% ( p<0.05). This shows an increase in stability.

LIL3, a Light-Harvesting Complex Protein, Links Terpenoid and Tetrapyrrole Biosynthesis in Arabidopsis thaliana1[OPEN

PubMed Central

Rothbart, Maxi; Herbst, Josephine; Wittmann, Daniel; Gruhl, Kirsten

2017-01-01

The LIL3 protein of Arabidopsis (Arabidopsis thaliana) belongs to the light-harvesting complex (LHC) protein family, which also includes the light-harvesting chlorophyll-binding proteins of photosystems I and II, the early-light-inducible proteins, PsbS involved in nonphotochemical quenching, and the one-helix proteins and their cyanobacterial homologs designated high-light-inducible proteins. Each member of this family is characterized by one or two LHC transmembrane domains (referred to as the LHC motif) to which potential functions such as chlorophyll binding, protein interaction, and integration of interacting partners into the plastid membranes have been attributed. Initially, LIL3 was shown to interact with geranylgeranyl reductase (CHLP), an enzyme of terpene biosynthesis that supplies the hydrocarbon chain for chlorophyll and tocopherol. Here, we show another function of LIL3 for the stability of protochlorophyllide oxidoreductase (POR). Multiple protein-protein interaction analyses suggest the direct physical interaction of LIL3 with POR but not with chlorophyll synthase. Consistently, LIL3-deficient plants exhibit substantial loss of POR as well as CHLP, which is not due to defective transcription of the POR and CHLP genes but to the posttranslational modification of their protein products. Interestingly, in vitro biochemical analyses provide novel evidence that LIL3 shows high binding affinity to protochlorophyllide, the substrate of POR. Taken together, this study suggests a critical role for LIL3 in the organization of later steps in chlorophyll biosynthesis. We suggest that LIL3 associates with POR and CHLP and thus contributes to the supply of the two metabolites, chlorophyllide and phytyl pyrophosphate, required for the final step in chlorophyll a synthesis. PMID:28432258

Velocity storage contribution to vestibular self-motion perception in healthy human subjects.

PubMed

Bertolini, G; Ramat, S; Laurens, J; Bockisch, C J; Marti, S; Straumann, D; Palla, A

2011-01-01

Self-motion perception after a sudden stop from a sustained rotation in darkness lasts approximately as long as reflexive eye movements. We hypothesized that, after an angular velocity step, self-motion perception and reflexive eye movements are driven by the same vestibular pathways. In 16 healthy subjects (25-71 years of age), perceived rotational velocity (PRV) and the vestibulo-ocular reflex (rVOR) after sudden decelerations (90°/s(2)) from constant-velocity (90°/s) earth-vertical axis rotations were simultaneously measured (PRV reported by hand-lever turning; rVOR recorded by search coils). Subjects were upright (yaw) or 90° left-ear-down (pitch). After both yaw and pitch decelerations, PRV rose rapidly and showed a plateau before decaying. In contrast, slow-phase eye velocity (SPV) decayed immediately after the initial increase. SPV and PRV were fitted with the sum of two exponentials: one time constant accounting for the semicircular canal (SCC) dynamics and one time constant accounting for a central process, known as velocity storage mechanism (VSM). Parameters were constrained by requiring equal SCC time constant and VSM time constant for SPV and PRV. The gains weighting the two exponential functions were free to change. SPV were accurately fitted (variance-accounted-for: 0.85 ± 0.10) and PRV (variance-accounted-for: 0.86 ± 0.07), showing that SPV and PRV curve differences can be explained by a greater relative weight of VSM in PRV compared with SPV (twofold for yaw, threefold for pitch). These results support our hypothesis that self-motion perception after angular velocity steps is be driven by the same central vestibular processes as reflexive eye movements and that no additional mechanisms are required to explain the perceptual dynamics.

LIL3, a Light-Harvesting Complex Protein, Links Terpenoid and Tetrapyrrole Biosynthesis in Arabidopsis thaliana.

PubMed

Hey, Daniel; Rothbart, Maxi; Herbst, Josephine; Wang, Peng; Müller, Jakob; Wittmann, Daniel; Gruhl, Kirsten; Grimm, Bernhard

2017-06-01

The LIL3 protein of Arabidopsis ( Arabidopsis thaliana ) belongs to the light-harvesting complex (LHC) protein family, which also includes the light-harvesting chlorophyll-binding proteins of photosystems I and II, the early-light-inducible proteins, PsbS involved in nonphotochemical quenching, and the one-helix proteins and their cyanobacterial homologs designated high-light-inducible proteins. Each member of this family is characterized by one or two LHC transmembrane domains (referred to as the LHC motif) to which potential functions such as chlorophyll binding, protein interaction, and integration of interacting partners into the plastid membranes have been attributed. Initially, LIL3 was shown to interact with geranylgeranyl reductase (CHLP), an enzyme of terpene biosynthesis that supplies the hydrocarbon chain for chlorophyll and tocopherol. Here, we show another function of LIL3 for the stability of protochlorophyllide oxidoreductase (POR). Multiple protein-protein interaction analyses suggest the direct physical interaction of LIL3 with POR but not with chlorophyll synthase. Consistently, LIL3-deficient plants exhibit substantial loss of POR as well as CHLP, which is not due to defective transcription of the POR and CHLP genes but to the posttranslational modification of their protein products. Interestingly, in vitro biochemical analyses provide novel evidence that LIL3 shows high binding affinity to protochlorophyllide, the substrate of POR. Taken together, this study suggests a critical role for LIL3 in the organization of later steps in chlorophyll biosynthesis. We suggest that LIL3 associates with POR and CHLP and thus contributes to the supply of the two metabolites, chlorophyllide and phytyl pyrophosphate, required for the final step in chlorophyll a synthesis. © 2017 American Society of Plant Biologists. All Rights Reserved.

Discrete pre-processing step effects in registration-based pipelines, a preliminary volumetric study on T1-weighted images

PubMed Central

2017-01-01

Pre-processing MRI scans prior to performing volumetric analyses is common practice in MRI studies. As pre-processing steps adjust the voxel intensities, the space in which the scan exists, and the amount of data in the scan, it is possible that the steps have an effect on the volumetric output. To date, studies have compared between and not within pipelines, and so the impact of each step is unknown. This study aims to quantify the effects of pre-processing steps on volumetric measures in T1-weighted scans within a single pipeline. It was our hypothesis that pre-processing steps would significantly impact ROI volume estimations. One hundred fifteen participants from the OASIS dataset were used, where each participant contributed three scans. All scans were then pre-processed using a step-wise pipeline. Bilateral hippocampus, putamen, and middle temporal gyrus volume estimations were assessed following each successive step, and all data were processed by the same pipeline 5 times. Repeated-measures analyses tested for a main effects of pipeline step, scan-rescan (for MRI scanner consistency) and repeated pipeline runs (for algorithmic consistency). A main effect of pipeline step was detected, and interestingly an interaction between pipeline step and ROI exists. No effect for either scan-rescan or repeated pipeline run was detected. We then supply a correction for noise in the data resulting from pre-processing. PMID:29023597

Analysis on burnup step effect for evaluating reactor criticality and fuel breeding ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saputra, Geby; Purnama, Aditya Rizki; Permana, Sidik

Criticality condition of the reactors is one of the important factors for evaluating reactor operation and nuclear fuel breeding ratio is another factor to show nuclear fuel sustainability. This study analyzes the effect of burnup steps and cycle operation step for evaluating the criticality condition of the reactor as well as the performance of nuclear fuel breeding or breeding ratio (BR). Burnup step is performed based on a day step analysis which is varied from 10 days up to 800 days and for cycle operation from 1 cycle up to 8 cycles reactor operations. In addition, calculation efficiency based onmore » the variation of computer processors to run the analysis in term of time (time efficiency in the calculation) have been also investigated. Optimization method for reactor design analysis which is used a large fast breeder reactor type as a reference case was performed by adopting an established reactor design code of JOINT-FR. The results show a criticality condition becomes higher for smaller burnup step (day) and for breeding ratio becomes less for smaller burnup step (day). Some nuclides contribute to make better criticality when smaller burnup step due to individul nuclide half-live. Calculation time for different burnup step shows a correlation with the time consuming requirement for more details step calculation, although the consuming time is not directly equivalent with the how many time the burnup time step is divided.« less

Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

PubMed

Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

2018-05-01

We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some differences in texture details. Moreover, quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation indicate that the short- and half-scan configurations yield results in close agreement with the ground-truth information and that of the full-scan configuration. The one-step method considered can compensate effectively for the nonlinear spectral response in full- and partial-angular-scan dual-energy CT. It can be exploited for enabling partial-angular-scan configurations on standard CT scanner without involving additional hardware. Visual inspection and quantitative studies reveal that, with the one-step method, partial-angular-scan configurations considered can perform at a level comparable to that of the full-scan configuration, thus suggesting the potential of the two partial-angular-scan configurations in reducing imaging dose and scan time in the standard single-kVp-switch full-scan CT in which two full rotations are performed. The work also yields insights into the investigation and design of other nonstandard scan configurations of potential practical significance in dual-energy CT. © 2018 American Association of Physicists in Medicine.

Muscle contributions to the acceleration of the whole body centre of mass during recovery from forward loss of balance by stepping in young and older adults.

PubMed

Graham, David F; Carty, Christopher P; Lloyd, David G; Barrett, Rod S

2017-01-01

The purpose of this study was to determine the muscular contributions to the acceleration of the whole body centre of mass (COM) of older compared to younger adults that were able to recover from forward loss of balance with a single step. Forward loss of balance was achieved by releasing participants (14 older adults and 6 younger adults) from a static whole-body forward lean angle of approximately 18 degrees. 10 older adults and 6 younger adults were able to recover with a single step and included in subsequent analysis. A scalable anatomical model consisting of 36 degrees-of-freedom was used to compute kinematics and joint moments from motion capture and force plate data. Forces for 92 muscle actuators were computed using Static Optimisation and Induced Acceleration Analysis was used to compute individual muscle contributions to the three-dimensional acceleration of the whole body COM. There were no significant differences between older and younger adults in step length, step time, 3D COM accelerations or muscle contributions to 3D COM accelerations. The stance and stepping leg Gastrocnemius and Soleus muscles were primarily responsible for the vertical acceleration experienced by the COM. The Gastrocnemius and Soleus from the stance side leg together with bilateral Hamstrings accelerated the COM forwards throughout balance recovery while the Vasti and Soleus of the stepping side leg provided the majority of braking accelerations following foot contact. The Hip Abductor muscles provided the greatest contribution to medial-lateral accelerations of the COM. Deficits in the neuromuscular control of the Gastrocnemius, Soleus, Vasti and Hip Abductors in particular could adversely influence balance recovery and may be important targets in interventions to improve balance recovery performance.

Muscle contributions to the acceleration of the whole body centre of mass during recovery from forward loss of balance by stepping in young and older adults

PubMed Central

Graham, David F.; Carty, Christopher P.; Lloyd, David G.

2017-01-01

The purpose of this study was to determine the muscular contributions to the acceleration of the whole body centre of mass (COM) of older compared to younger adults that were able to recover from forward loss of balance with a single step. Forward loss of balance was achieved by releasing participants (14 older adults and 6 younger adults) from a static whole-body forward lean angle of approximately 18 degrees. 10 older adults and 6 younger adults were able to recover with a single step and included in subsequent analysis. A scalable anatomical model consisting of 36 degrees-of-freedom was used to compute kinematics and joint moments from motion capture and force plate data. Forces for 92 muscle actuators were computed using Static Optimisation and Induced Acceleration Analysis was used to compute individual muscle contributions to the three-dimensional acceleration of the whole body COM. There were no significant differences between older and younger adults in step length, step time, 3D COM accelerations or muscle contributions to 3D COM accelerations. The stance and stepping leg Gastrocnemius and Soleus muscles were primarily responsible for the vertical acceleration experienced by the COM. The Gastrocnemius and Soleus from the stance side leg together with bilateral Hamstrings accelerated the COM forwards throughout balance recovery while the Vasti and Soleus of the stepping side leg provided the majority of braking accelerations following foot contact. The Hip Abductor muscles provided the greatest contribution to medial-lateral accelerations of the COM. Deficits in the neuromuscular control of the Gastrocnemius, Soleus, Vasti and Hip Abductors in particular could adversely influence balance recovery and may be important targets in interventions to improve balance recovery performance. PMID:29069097

A comparison of simple global kinetic models for coal devolatilization with the CPD model

DOE PAGES

Richards, Andrew P.; Fletcher, Thomas H.

2016-08-01

Simulations of coal combustors and gasifiers generally cannot incorporate the complexities of advanced pyrolysis models, and hence there is interest in evaluating simpler models over ranges of temperature and heating rate that are applicable to the furnace of interest. In this paper, six different simple model forms are compared to predictions made by the Chemical Percolation Devolatilization (CPD) model. The model forms included three modified one-step models, a simple two-step model, and two new modified two-step models. These simple model forms were compared over a wide range of heating rates (5 × 10 3 to 10 6 K/s) at finalmore » temperatures up to 1600 K. Comparisons were made of total volatiles yield as a function of temperature, as well as the ultimate volatiles yield. Advantages and disadvantages for each simple model form are discussed. In conclusion, a modified two-step model with distributed activation energies seems to give the best agreement with CPD model predictions (with the fewest tunable parameters).« less

Enhancing field GP engagement in hospital-based studies. Rationale, design, main results and participation in the Diagest 3-GP motivation study.

PubMed

Berkhout, Christophe; Vandaele-Bétancourt, Marie; Robert, Stéphane; Lespinasse, Solène; Mitha, Gamil; Bradier, Quentin; Vambergue, Anne; Fontaine, Pierre

2012-06-21

Diagest 3 was a study aimed at lowering the risk of developing type 2 diabetes within 3 years after childbirth. Women with gestational diabetes were enrolled in the study. After childbirth, the subjects showed little interest in the structured education programme and did not attend workshops. Their general practitioners (GPs) were approached to help motivate the subjects to participate in Diagest 3, but the GPs were reluctant. The present study aimed to understand field GPs' attitudes towards hospital-based studies, and to develop strategies to enhance their involvement and reduce subject drop-out rates. We used a three-step process: step one used a phenomenological approach exploring the beliefs, attitudes, motivations and environmental factors contributing to the GPs' level of interest in the study. Data were collected in face-to-face interviews and coded by hand and with hermeneutic software to develop distinct GP profiles. Step two was a cross-sectional survey by questionnaire to determine the distribution of the profiles in the GP study population and whether completion of an attached case report form (CRF) was associated with a particular GP profile. In step three, we assessed the impact of the motivation study on participation rates in the main study. Fifteen interviews were conducted to achieve data saturation. Theorisation led to the definition of 4 distinct GP profiles. The response rate to the questionnaire was 73%, but dropped to 52% when a CRF was attached. The link between GP profiles and the rate of CRF completion remains to be verified. The GPs provided data on the CRF that was of comparable quality to those collected in the main trial. Our analysis showed that the motivation study increased overall participation in the main study by 23%, accounting for 16% (24/152) of all final visits for 536 patients who were initially enrolled in the Diagest 3 study. When a hospital-led study explores issues in primary care, its design must anticipate GP participation early in the trial. Based on our questionnaire response rates, we found that one in two GPs were willing to participate in our hospital-led study, regardless of their initial attitudes.

A Practical Guide for Managing Customer Service in Base Civil Engineering.

DTIC Science & Technology

1988-04-01

IMPROVING CUSTOMER SERVICE IN BASE CIVIL ENGINEERING Step One: Evaluate Present Service Quality .. ......... .11 Step Two: Develop and Clarify a...cross sectional viewpoint. In chapter three, specific steps will be presented for managers to evaluate and improve the present level of service quality in...customer service in base civil engineering or any other organization for that matter is to evaluate the present level of service quality (1:170). Data

Range image segmentation using Zernike moment-based generalized edge detector

NASA Technical Reports Server (NTRS)

Ghosal, S.; Mehrotra, R.

1992-01-01

The authors proposed a novel Zernike moment-based generalized step edge detection method which can be used for segmenting range and intensity images. A generalized step edge detector is developed to identify different kinds of edges in range images. These edge maps are thinned and linked to provide final segmentation. A generalized edge is modeled in terms of five parameters: orientation, two slopes, one step jump at the location of the edge, and the background gray level. Two complex and two real Zernike moment-based masks are required to determine all these parameters of the edge model. Theoretical noise analysis is performed to show that these operators are quite noise tolerant. Experimental results are included to demonstrate edge-based segmentation technique.

A new approach for bioassays based on frequency- and time-domain measurements of magnetic nanoparticles.

PubMed

Oisjöen, Fredrik; Schneiderman, Justin F; Astalan, Andrea Prieto; Kalabukhov, Alexey; Johansson, Christer; Winkler, Dag

2010-01-15

We demonstrate a one-step wash-free bioassay measurement system capable of tracking biochemical binding events. Our approach combines the high resolution of frequency- and high speed of time-domain measurements in a single device in combination with a fast one-step bioassay. The one-step nature of our magnetic nanoparticle (MNP) based assay reduces the time between sample extraction and quantitative results while mitigating the risks of contamination related to washing steps. Our method also enables tracking of binding events, providing the possibility of, for example, investigation of how chemical/biological environments affect the rate of a binding process or study of the action of certain drugs. We detect specific biological binding events occurring on the surfaces of fluid-suspended MNPs that modify their magnetic relaxation behavior. Herein, we extrapolate a modest sensitivity to analyte of 100 ng/ml with the present setup using our rapid one-step bioassay. More importantly, we determine the size-distributions of the MNP systems with theoretical fits to our data obtained from the two complementary measurement modalities and demonstrate quantitative agreement between them. Copyright 2009 Elsevier B.V. All rights reserved.

Bioleaching of rare earth and radioactive elements from red mud using Penicillium tricolor RM-10.

PubMed

Qu, Yang; Lian, Bin

2013-05-01

The aim of this work is to investigate biological leaching of rare earth elements (REEs) and radioactive elements from red mud, and to evaluate the radioactivity of the bioleached red mud used for construction materials. A filamentous, acid-producing fungi named RM-10, identified as Penicillium tricolor, is isolated from red mud. In our bioleaching experiments by using RM-10, a total concentration of 2% (w/v) red mud under one-step bioleaching process was generally found to give the maximum leaching ratios of the REEs and radioactive elements. However, the highest extraction yields are achieved under two-step bioleaching process at 10% (w/v) pulp density. At pulp densities of 2% and 5% (w/v), red mud processed under both one- and two-step bioleaching can meet the radioactivity regulations in China. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bond strength durability of self-etching adhesives and resin cements to dentin.

PubMed

Chaves, Carolina de Andrade Lima; de Melo, Renata Marques; Passos, Sheila Pestana; Camargo, Fernanda Pelógia; Bottino, Marco Antonio; Balducci, Ivan

2009-01-01

To evaluate the microtensile bond strength (microTBS) of one- (Xeno III, Dentsply) and two-step (Tyrian-One Step Plus, Bisco) self-etching adhesive systems bonded to dentin and cemented to chemically cured (C&B Metabond) or light-cured paste of a dual-cure resin cement (Variolink II, Ivoclar) within a short (24 h) and long period of evaluation (90 days). Forty recently extracted human molars had their roots removed and their occlusal dentin exposed and ground wet with 600-grit SiC paper. After application of one of the adhesives, the resin cement was applied to the bonded surface and a composite resin block was incrementally built up to a height of 5 mm (n=10). The restored teeth were stored in distilled water at 37 degrees C for 7 days. The teeth were then cut along two axes (x and y), producing beam-shaped specimens with 0.8 mm(2) cross-sectional area, which were subjected to microTBS testing at a crosshead speed of 0.05 mm/min and stressed to failure after 24 h or 90 days of storage in water. The microTBS data in MPa were subjected to three-way analysis of variance and Tukey's test (alpha= 0.05). The interaction effect for all three factors was statistically significant (three-way ANOVA, p<0.001). All eight experimental means (MPa) were compared by the Tukey's test (p<0.05) and the following results were obtained: Tyrian-One Step Plus /C&B/24 h (22.4+/-7.3); Tyrian-One Step Plus /Variolink II/24 h (39.4+/-11.6); Xeno III/C&B/24 h (40.3+/-12.9); Xeno III/Variolink II/24 h (25.8+/-10.5); Tyrian-One Step Plus /C&B/90 d (22.1+/-12.8) Tyrian-One Step Plus/VariolinkII/90 d (24.2+/-14.2); Xeno III/C&B/90 d (27.0+/-13.5); Xeno III/Variolink II/90 d (33.0+/-8.9). Xeno III/Variolink II was the luting agent/adhesive combination that provided the most promising bond strength after 90 days of storage in water.

Application of blind source separation to gamma ray spectra acquired by GRaND around Vesta

NASA Astrophysics Data System (ADS)

Mizzon, H.; Toplis, M. J.; Forni, O.; Prettyman, T. H.; Raymond, C. A.; Russell, C. T.

2012-12-01

The bismuth germinate (BGO) scintillator is one of the sensors of the gamma ray and neutron detector (GRaND)1 on board the Dawn spacecraft, that has spent just over one year in orbit around the asteroid 4-Vesta. The BGO detector is excited by energetic gamma-rays produced by galactic cosmic rays (GCR) or energetic solar particles interacting either with Vesta and/or the Dawn spacecraft. In detail, during periods of quiet solar activity, gamma ray spectra produced by the scintillator can be considered as consisting of three signals: i) a contribution of gamma-rays from Vesta produced by GCR interactions at the asteroid's surface, ii) a contribution from the spacecraft excited by neutrons coming from Vesta, and iii) a contribution of the spacecraft excited by local interaction with galactic cosmic rays. While the first two contributions should be positive functions of the solid angle of Vesta in the field of view during acquisition, the last one should have a negative dependence because Vesta partly shields the spacecraft from GCR. This theoretical mix can be written formally as: S=aΩSV+bΩSSCNV+c(4π-Ω)SSCGCR (1) where S is the series of recorded spectra, Ω is the solid angle, SV is the contribution of gamma rays coming from Vesta, SSCNV is the contribution of gamma rays coming from the spacecraft excited by the neutron coming from Vesta and SSCGCR is the contribution of gamma rays coming from the spacecraft excited by GCR. A blind source separation method called independent component analysis enables separating additive subcomponents supposing the mutual statistical independence of the non-Gaussian source signals2. Applying this method to BGO spectra acquired during the first three months of the low-altitude measurement orbit (LAMO) reveals two main independent components. The first one is dominated by the positron electron annihilation peak and is positively correlated to the solid angle. The second is negatively correlated to the solid angle and displays peaks of elements present in the spacecraft, of energy in the range 1 to 3.5 MeV. At energy >3.5 MeV, the dominant independent component highlighted by this method has no significant peaks, suggesting that it is not influenced by Vesta itself which is known to have a strong signal associated with iron at 7.6 MeV. Our method therefore represents a first step in retrieving the contribution of the spacecraft that could be used in conjunction with the mixing equation (1) to determine the contribution from the planet itself. 1 : Prettyman, T. H., Mcsween, Jr., H. Y., Feldman, W. C., JUN 2010. Dawn's GRaND to map the chemical composition of asteroids Vesta and Ceres. Geochimica and Cosmochimica Acta 74 (12, 1), A832, Con- ference on Goldschmidt 2010 - Earth, Energy, and the Environment, Knoxville, TN, JUN 13-18, 2010. 2 : Hyvarinen, A., Oja, E., May-Jun 2000. Independent component analysis: algorithms and applications. Neural Networks 13 (4-5), 411-430.

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches.

PubMed

Clegg, Paul S; Tavacoli, Joe W; Wilde, Pete J

2016-01-28

Multiple emulsions have great potential for application in food science as a means to reduce fat content or for controlled encapsulation and release of actives. However, neither production nor stability is straightforward. Typically, multiple emulsions are prepared via two emulsification steps and a variety of approaches have been deployed to give long-term stability. It is well known that multiple emulsions can be prepared in a single step by harnessing emulsion inversion, although the resulting emulsions are usually short lived. Recently, several contrasting methods have been demonstrated which give rise to stable multiple emulsions via one-step production processes. Here we review the current state of microfluidic, polymer-stabilized and particle-stabilized approaches; these rely on phase separation, the role of electrolyte and the trapping of solvent with particles respectively.

A Poisson approach to the validation of failure time surrogate endpoints in individual patient data meta-analyses.

PubMed

Rotolo, Federico; Paoletti, Xavier; Burzykowski, Tomasz; Buyse, Marc; Michiels, Stefan

2017-01-01

Surrogate endpoints are often used in clinical trials instead of well-established hard endpoints for practical convenience. The meta-analytic approach relies on two measures of surrogacy: one at the individual level and one at the trial level. In the survival data setting, a two-step model based on copulas is commonly used. We present a new approach which employs a bivariate survival model with an individual random effect shared between the two endpoints and correlated treatment-by-trial interactions. We fit this model using auxiliary mixed Poisson models. We study via simulations the operating characteristics of this mixed Poisson approach as compared to the two-step copula approach. We illustrate the application of the methods on two individual patient data meta-analyses in gastric cancer, in the advanced setting (4069 patients from 20 randomized trials) and in the adjuvant setting (3288 patients from 14 randomized trials).

Immediate adhesive properties to dentin and enamel of a universal adhesive associated with a hydrophobic resin coat.

PubMed

Perdigão, J; Muñoz, M A; Sezinando, A; Luque-Martinez, I V; Staichak, R; Reis, A; Loguercio, A D

2014-01-01

To evaluate the effect of acid etching and application of a hydrophobic resin coat on the enamel/dentin bond strengths and degree of conversion (DC) within the hybrid layer of a universal adhesive system (G-Bond Plus [GB]). A total of 60 extracted third molars were divided into four groups for bond-strength testing, according to the adhesive strategy: GB applied as a one-step self-etch adhesive (1-stepSE); GB applied as in 1-stepSE followed by one coat of the hydrophobic resin Heliobond (2-stepSE); GB applied as a two-step etch-and-rinse adhesive (2-stepER); GB applied as in 2-stepER followed by one coat of the hydrophobic resin Heliobond (3-stepER). There were 40 teeth used for enamel microshear bond strength (μSBS) and DC; and 20 teeth used for dentin microtensile bond strength (μTBS) and DC. After restorations were constructed, specimens were stored in water (37°C/24 h) and then tested at 0.5 mm/min (μTBS) or 1.0 mm/min (μSBS). Enamel-resin and dentin-resin interfaces from each group were evaluated for DC using micro-Raman spectroscopy. Data were analyzed with two-way analysis of variance for each substrate and the Tukey test (α=0.05). For enamel, the use of a hydrophobic resin coat resulted in statistically significant higher mean enamel μSBS only for the ER strategy (3-stepER vs 2-stepER, p<0.0002). DC was significantly improved for the SE strategy (p<0.00002). For dentin, the use of a hydrophobic resin coat resulted in significantly higher dentin mean μTBS only for the SE strategy (2-stepSE vs 1-stepSE, p<0.0007). DC was significantly improved in groups 2-stepSE and 3-stepER when compared with 1-stepSE and 2-stepER, respectively (p<0.0009). The use of a hydrophobic resin coat may be beneficial for the selective enamel etching technique, because it improves bond strengths to enamel when applied with the ER strategy and to dentin when used with the SE adhesion strategy. The application of a hydrophobic resin coat may improve DC in resin-dentin interfaces formed with either the SE or the ER strategy. On enamel, DC may benefit from the application of a hydrophobic resin coat over 1-stepSE adhesives.

Multi-step routes of capuchin monkeys in a laser pointer traveling salesman task.

PubMed

Howard, Allison M; Fragaszy, Dorothy M

2014-09-01

Prior studies have claimed that nonhuman primates plan their routes multiple steps in advance. However, a recent reexamination of multi-step route planning in nonhuman primates indicated that there is no evidence for planning more than one step ahead. We tested multi-step route planning in capuchin monkeys using a pointing device to "travel" to distal targets while stationary. This device enabled us to determine whether capuchins distinguish the spatial relationship between goals and themselves and spatial relationships between goals and the laser dot, allocentrically. In Experiment 1, two subjects were presented with identical food items in Near-Far (one item nearer to subject) and Equidistant (both items equidistant from subject) conditions with a laser dot visible between the items. Subjects moved the laser dot to the items using a joystick. In the Near-Far condition, one subject demonstrated a bias for items closest to self but the other subject chose efficiently. In the second experiment, subjects retrieved three food items in similar Near-Far and Equidistant arrangements. Both subjects preferred food items nearest the laser dot and showed no evidence of multi-step route planning. We conclude that these capuchins do not make choices on the basis of multi-step look ahead strategies. © 2014 Wiley Periodicals, Inc.

Facile and easily popularized synthesis of L-cysteine-functionalized magnetic nanoparticles based on one-step functionalization for highly efficient enrichment of glycopeptides.

PubMed

Feng, Xiaoyan; Deng, Chunhui; Gao, Mingxia; Zhang, Xiangmin

2018-01-01

Protein glycosylation is one of the most important post-translational modifications. Also, efficient enrichment and separation of glycopeptides from complex samples are crucial for the thorough analysis of glycosylation. Developing novel hydrophilic materials with facile and easily popularized synthesis is an urgent need in large-scale glycoproteomics research. Herein, for the first time, a one-step functionalization strategy based on metal-organic coordination was proposed and Fe 3 O 4 nanoparticles were directly functionalized with zwitterionic hydrophilic L-cysteine (L-Cys), greatly simplifying the synthetic procedure. The easily synthesized Fe 3 O 4 /L-Cys possessed excellent hydrophilicity and brief composition, contributing to affinity for glycopeptides and reduction in nonspecific interaction. Thus, Fe 3 O 4 /L-Cys nanoparticles showed outstanding sensitivity (25 amol/μL), high selectivity (mixture of bovine serum albumin and horseradish peroxidase tryptic digests at a mass ratio of 100:1), good reusability (five repeated times), and stability (room temperature storage of 1 month). Encouragingly, in the glycosylation analysis of human serum, a total of 376 glycopeptides with 393 N-glycosylation sites corresponding to 118 glycoproteins were identified after enrichment with Fe 3 O 4 /L-Cys, which was superior to ever reported L-Cys modified magnetic materials. Furthermore, applying the one-step functionalization strategy, cysteamine and glutathione respectively direct-functionalized Fe 3 O 4 nanoparticles were successfully synthesized and also achieved efficient glycopeptide enrichment in human serum. The results indicated that we have presented an efficient and easily popularized strategy in glycoproteomics as well as in the synthesis of novel materials. Graphical abstract Fe 3 O 4 /L-Cys nanoparticles based on one-step functionalization for highly efficient enrichment of glycopeptides.

Leadership in Context: Observations from Two Island Communities

ERIC Educational Resources Information Center

Billot, Jennie

2005-01-01

This article refers to just one example of specificity of context, the small island community. Islands can be viewed as well-bounded communities, often with an identity that seeks to be one step removed from being the politically dependent neighbour. Two islands serve to exemplify the significance of context: The Island of Jersey (Channel…

Particle Simulation of Coulomb Collisions: Comparing the Methods of Takizuka & Abe and Nanbu

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, C; Lin, T; Caflisch, R

2007-05-22

The interactions of charged particles in a plasma are in a plasma is governed by the long-range Coulomb collision. We compare two widely used Monte Carlo models for Coulomb collisions. One was developed by Takizuka and Abe in 1977, the other was developed by Nanbu in 1997. We perform deterministic and stochastic error analysis with respect to particle number and time step. The two models produce similar stochastic errors, but Nanbu's model gives smaller time step errors. Error comparisons between these two methods are presented.

Divergent Synthesis of Quinolone Natural Products from Pseudonocardia sp. CL38489

PubMed Central

Geddis, Stephen M.; Carro, Laura; Hodgkinson, James T.

2016-01-01

Two divergent synthetic routes are reported offering access to four quinolone natural products from Pseudonocardia sp. CL38489. Key steps to the natural products involved a regioselective epoxidation, an intramolecular Buchwald–Hartwig amination and a final acid‐catalysed 1,3‐allylic‐alcohol rearrangement to give two of the natural products in one step. This study completes the synthesis of all eight antibacterial quinolone natural products reported in the family. In addition, this modular strategy enables an improved synthesis towards two natural products previously reported. PMID:28111524

A New Insight into the Mechanism of NADH Model Oxidation by Metal Ions in Non-Alkaline Media.

PubMed

Yang, Jin-Dong; Chen, Bao-Long; Zhu, Xiao-Qing

2018-06-11

For a long time, it has been controversial that the three-step (e-H+-e) or two-step (e-H•) mechanism was used for the oxidations of NADH and its models by metal ions in non-alkaline media. The latter mechanism has been accepted by the majority of researchers. In this work, 1-benzyl-1,4-dihydronicotinamide (BNAH) and 1-phenyl-l,4-dihydronicotinamide (PNAH) are used as NADH models, and ferrocenium (Fc+) metal ion as an electron acceptor. The kinetics for oxidations of the NADH models by Fc+ in pure acetonitrile were monitored by using UV-Vis absorption and quadratic relationship between of kobs and the concentrations of NADH models were found for the first time. The rate expression of the reactions developed according to the three-step mechanism is quite consistent with the quadratic curves. The rate constants, thermodynamic driving forces and KIEs of each elementary step for the reactions were estimated. All the results supported the three-step mechanism. The intrinsic kinetic barriers of the proton transfer from BNAH+• to BNAH and the hydrogen atom transfer from BNAH+• to BNAH+• were estimated, the results showed that the former is 11.8 kcal/mol, and the latter is larger than 24.3 kcal/mol. It is the large intrinsic kinetic barrier of the hydrogen atom transfer that makes the reactions choose the three-step rather than two-step mechanism. Further investigation of the factors affecting the intrinsic kinetic barrier of chemical reactions indicated that the large intrinsic kinetic barrier of the hydrogen atom transfer originated from the repulsion of positive charges between BNAH+• and BNAH+•. The greatest contribution of this work is the discovery of the quadratic dependence of kobs on the concentrations of the NADH models, which is inconsistent with the conventional viewpoint of the "two-step mechanism" on the oxidations of NADH and its models by metal ions in the non-alkaline media.

Unifying Temporal and Structural Credit Assignment Problems

NASA Technical Reports Server (NTRS)

Agogino, Adrian K.; Tumer, Kagan

2004-01-01

Single-agent reinforcement learners in time-extended domains and multi-agent systems share a common dilemma known as the credit assignment problem. Multi-agent systems have the structural credit assignment problem of determining the contributions of a particular agent to a common task. Instead, time-extended single-agent systems have the temporal credit assignment problem of determining the contribution of a particular action to the quality of the full sequence of actions. Traditionally these two problems are considered different and are handled in separate ways. In this article we show how these two forms of the credit assignment problem are equivalent. In this unified frame-work, a single-agent Markov decision process can be broken down into a single-time-step multi-agent process. Furthermore we show that Monte-Carlo estimation or Q-learning (depending on whether the values of resulting actions in the episode are known at the time of learning) are equivalent to different agent utility functions in a multi-agent system. This equivalence shows how an often neglected issue in multi-agent systems is equivalent to a well-known deficiency in multi-time-step learning and lays the basis for solving time-extended multi-agent problems, where both credit assignment problems are present.

Color stability of nanocomposites polished with one-step systems.

PubMed

Ergücü, Zeynep; Türkün, L Sebnem; Aladag, Akin

2008-01-01

This study compared the color changes of five novel resin composites polished with two one-step polishing systems when exposed to coffee solution. The resin composites tested were Filtek Supreme XT, Grandio, CeramX, Premise and Tetric EvoCeram. A total of 150 discs (30/resin composites, 10 x 2 mm) were fabricated. Ten specimens/resin composites cured under Mylar strips served as the control. The other samples were polished with PoGo and OptraPol discs for 30 seconds using a slow speed handpiece and immersed in coffee (Nescafé) for seven days. Color measurements were made with Vita Easyshade at baseline and after one and seven days. Repeated Measures ANOVA and Bonferroni tests were used for statistical analyses (p< or =0.05). The differences between the mean DeltaE* values for the resin composites polished with two different one-step systems were statistically significant (p<0.05). After one week, all materials exhibited significant color changes compared to baseline. All Mylar finished specimens showed the most intense staining (p<0.05). There were no significant differences between the OptraPol and PoGo polished groups. Mylar-finished specimens of CeramX, Tetric EvoCeram, Premise and Filtek Supreme XT presented the greatest staining (p<0.05). For Grandio, there were no significant differences between the Mylar and PoGo groups, while the most stain resistant surfaces were attained with OptraPol. Removing the outermost resin layer by polishing procedures is essential to achieving a stain resistant, more esthetically stable surface. One-step polishing systems can be used successfully for polishing nanocomposites.

Non-equivalent contributions of maternal and paternal genomes to early plant embryogenesis.

PubMed

Del Toro-De León, Gerardo; García-Aguilar, Marcelina; Gillmor, C Stewart

2014-10-30

Zygotic genome activation in metazoans typically occurs several hours to a day after fertilization, and thus maternal RNAs and proteins drive early animal embryo development. In plants, despite several molecular studies of post-fertilization transcriptional activation, the timing of zygotic genome activation remains a matter of debate. For example, two recent reports that used different hybrid ecotype combinations for RNA sequence profiling of early Arabidopsis embryo transcriptomes came to divergent conclusions. One identified paternal contributions that varied by gene, but with overall maternal dominance, while the other found that the maternal and paternal genomes are transcriptionally equivalent. Here we assess paternal gene activation functionally in an isogenic background, by performing a large-scale genetic analysis of 49 EMBRYO DEFECTIVE genes and testing the ability of wild-type paternal alleles to complement phenotypes conditioned by mutant maternal alleles. Our results demonstrate that wild-type paternal alleles for nine of these genes are completely functional 2 days after pollination, with the remaining 40 genes showing partial activity beginning at 2, 3 or 5 days after pollination. Using our functional assay, we also demonstrate that different hybrid combinations exhibit significant variation in paternal allele activation, reconciling the apparently contradictory results of previous transcriptional studies. The variation in timing of gene function that we observe confirms that paternal genome activation does not occur in one early discrete step, provides large-scale functional evidence that maternal and paternal genomes make non-equivalent contributions to early plant embryogenesis, and uncovers an unexpectedly profound effect of hybrid genetic backgrounds on paternal gene activity.

26 CFR 1.401(a)(4)-2 - Nondiscrimination in amount of employer contributions under a defined contribution plan.

Code of Federal Regulations, 2014 CFR

2014-04-01

... greater of the allocations under two or more formulas, one of which is a top-heavy formula, the top-heavy... is the greater of the allocations under two or more formulas, and one or more of those formulas is... provide uniform allocations are permitted to satisfy this requirement by meeting one of the safe harbors...

26 CFR 1.401(a)(4)-2 - Nondiscrimination in amount of employer contributions under a defined contribution plan.

Code of Federal Regulations, 2012 CFR

2012-04-01

... greater of the allocations under two or more formulas, one of which is a top-heavy formula, the top-heavy... is the greater of the allocations under two or more formulas, and one or more of those formulas is... provide uniform allocations are permitted to satisfy this requirement by meeting one of the safe harbors...

One Step Forward, Two Steps Back? Work Experience, Equal Opportunities and TVEI.

ERIC Educational Resources Information Center

Heath, Sue

1995-01-01

A case study of work experience provided in a British project committed to gender equality shows that the nature of work experience--its alliance with labor market needs--makes it virtually impossible to meet equal opportunity objectives. Work experience tends to reinforce existing gender divisions in the labor market. (SK)

Efficient Synthesis of 4,8-Ditoluoyl-1,5-Dihydroxynaphthalene

NASA Technical Reports Server (NTRS)

Tyson, Daniel S.; Meador, Michael A.

2003-01-01

4,8-Ditoluoyl-1,5-dihydroxynaphthalene was synthesized in quantitative yield from the corresponding methylenequinone via base-catalyzed hydration. Alkaline treatment gives the title compound in one step with a 99% yield, an improvement of 80% compared to the acidic, two step literature method for preparing 4,8-dibenzoyl-1,5-dihydroxynaphthalene.

Mobile magnetic particles as solid-supports for rapid surface-based bioanalysis in continuous flow.

PubMed

Peyman, Sally A; Iles, Alexander; Pamme, Nicole

2009-11-07

An extremely versatile microfluidic device is demonstrated in which multi-step (bio)chemical procedures can be performed in continuous flow. The system operates by generating several co-laminar flow streams, which contain reagents for specific (bio)reactions across a rectangular reaction chamber. Functionalized magnetic microparticles are employed as mobile solid-supports and are pulled from one side of the reaction chamber to the other by use of an external magnetic field. As the particles traverse the co-laminar reagent streams, binding and washing steps are performed on their surface in one operation in continuous flow. The applicability of the platform was first demonstrated by performing a proof-of-principle binding assay between streptavidin coated magnetic particles and biotin in free solution with a limit of detection of 20 ng mL(-1) of free biotin. The system was then applied to a mouse IgG sandwich immunoassay as a first example of a process involving two binding steps and two washing steps, all performed within 60 s, a fraction of the time required for conventional testing.

The influence of tightening sequence and method on screw preload in implant superstructures.

PubMed

Al-Sahan, Maha M; Al Maflehi, Nassr S; Akeel, Riyadh F

2014-01-01

This study evaluated the effect of six screw-tightening sequences and two tightening methods on the screw preload in implant-supported superstructures. The preload was measured using strain gauges following the screw tightening of a metal framework connected to four implants. The experiment included six sequences ([1] 1-2-3-4, [2] 4-2-3-1, [3] 4-3-1-2, [4] 1-4-2-3, [5] 2-3-4-1, and [6] 3-2-4-1), two methods (onestep, three-step), and five replications. Significant differences were found between tightening sequences and methods. In the three-step method, a higher total preload was found in sequences 2 (312 ± 85 N), 3 (246 ± 54 N), and 4 (310 ± 96 N). In the one-step method, a higher total preload was found in sequences 1 (286 ± 94 N), 5 (764 ± 142 N), and 6 (350 ± 69 N). It is concluded that the highest total screw preload was achieved when anterior implants of the superstructure were first tightened in one step, followed by posterior implants.

Drastic changes of (p,t) analyzing powers for the isotopes /sup 58,60,62,64/Ni and marked incident-energy dependence of the analyzing powers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toba Y.; Yagi, K.

1984-01-01

Drastic changes of (p,t) analyzing powers for the four Ni isotopes in ground-state transitions were observed. The changes are not explained by direct one-step processes but are interpreted by including strong two-step (p,d) (d,t) processes. Interference between the two processes of comparable intensities is essential. Marked incident-energy dependence of the analyzing powers is interpreted similarly.

Synthesis and characterization of citrate-based fluorescent small molecules and biodegradable polymers.

PubMed

Xie, Zhiwei; Kim, Jimin P; Cai, Qing; Zhang, Yi; Guo, Jinshan; Dhami, Ranjodh S; Li, Li; Kong, Bin; Su, Yixue; Schug, Kevin A; Yang, Jian

2017-03-01

Novel citric acid based photoluminescent dyes and biodegradable polymers are synthesized via a facile "one-pot" reaction. A comprehensive understanding of the fluorescence mechanisms of the resulting citric acid-based fluorophores is reported. Two distinct types of fluorophores are identified: a thiozolopyridine family with high quantum yield, long lifetime, and exceptional photostability, and a dioxopyridine family with relatively lower quantum yield, multiple lifetimes, and solvent-dependent band shifting behavior. Applications in molecular labeling and cell imaging were demonstrated. The above discoveries contribute to the field of fluorescence chemistry and have laid a solid foundation for further development of new fluorophores and materials that show promise in a diversity of fluorescence-based applications. Photoluminescent materials are pivotal for fluorescence based imaging, labeling and sensing applications. Understanding their fluorescence mechanism is challenging and imperative. We develop a new class of citric acid-derived fluorescent materials in forms of polymers and small molecular dyes by a one-step solvent free reaction. We discovered two different classes of citric acid-derived fluorophores. A two-ring thiozolopyridine structure demonstrates strong fluorescence and exceptional resistance to photo-bleaching. A one-ring dioxopyridine exhibits relative weak fluorescence but with intriguing excitation and solvent-dependent emission wavelength shifting. Our methodology of synthesizing citric acid-derived fluorophores and the understanding on their luminescence are instrumental to the design and production of a large number of new photoluminescent materials for biological and biomedical applications. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Exponential integration algorithms applied to viscoplasticity

NASA Technical Reports Server (NTRS)

Freed, Alan D.; Walker, Kevin P.

1991-01-01

Four, linear, exponential, integration algorithms (two implicit, one explicit, and one predictor/corrector) are applied to a viscoplastic model to assess their capabilities. Viscoplasticity comprises a system of coupled, nonlinear, stiff, first order, ordinary differential equations which are a challenge to integrate by any means. Two of the algorithms (the predictor/corrector and one of the implicits) give outstanding results, even for very large time steps.

Neural Correlates of Temporal Credit Assignment in the Parietal Lobe

PubMed Central

Eisenberg, Ian; Gottlieb, Jacqueline

2014-01-01

Empirical studies of decision making have typically assumed that value learning is governed by time, such that a reward prediction error arising at a specific time triggers temporally-discounted learning for all preceding actions. However, in natural behavior, goals must be acquired through multiple actions, and each action can have different significance for the final outcome. As is recognized in computational research, carrying out multi-step actions requires the use of credit assignment mechanisms that focus learning on specific steps, but little is known about the neural correlates of these mechanisms. To investigate this question we recorded neurons in the monkey lateral intraparietal area (LIP) during a serial decision task where two consecutive eye movement decisions led to a final reward. The underlying decision trees were structured such that the two decisions had different relationships with the final reward, and the optimal strategy was to learn based on the final reward at one of the steps (the “F” step) but ignore changes in this reward at the remaining step (the “I” step). In two distinct contexts, the F step was either the first or the second in the sequence, controlling for effects of temporal discounting. We show that LIP neurons had the strongest value learning and strongest post-decision responses during the transition after the F step regardless of the serial position of this step. Thus, the neurons encode correlates of temporal credit assignment mechanisms that allocate learning to specific steps independently of temporal discounting. PMID:24523935

A cascaded two-step Kalman filter for estimation of human body segment orientation using MEMS-IMU.

PubMed

Zihajehzadeh, S; Loh, D; Lee, M; Hoskinson, R; Park, E J

2014-01-01

Orientation of human body segments is an important quantity in many biomechanical analyses. To get robust and drift-free 3-D orientation, raw data from miniature body worn MEMS-based inertial measurement units (IMU) should be blended in a Kalman filter. Aiming at less computational cost, this work presents a novel cascaded two-step Kalman filter orientation estimation algorithm. Tilt angles are estimated in the first step of the proposed cascaded Kalman filter. The estimated tilt angles are passed to the second step of the filter for yaw angle calculation. The orientation results are benchmarked against the ones from a highly accurate tactical grade IMU. Experimental results reveal that the proposed algorithm provides robust orientation estimation in both kinematically and magnetically disturbed conditions.

Kinetically Defined Mechanisms and Positions of Action of Two New Modulators of Glucocorticoid Receptor-regulated Gene Induction*

PubMed Central

Pradhan, Madhumita A.; Blackford, John A.; Devaiah, Ballachanda N.; Thompson, Petria S.; Chow, Carson C.; Singer, Dinah S.; Simons, S. Stoney

2016-01-01

Most of the steps in, and many of the factors contributing to, glucocorticoid receptor (GR)-regulated gene induction are currently unknown. A competition assay, based on a validated chemical kinetic model of steroid hormone action, is now used to identify two new factors (BRD4 and negative elongation factor (NELF)-E) and to define their sites and mechanisms of action. BRD4 is a kinase involved in numerous initial steps of gene induction. Consistent with its complicated biochemistry, BRD4 is shown to alter both the maximal activity (Amax) and the steroid concentration required for half-maximal induction (EC50) of GR-mediated gene expression by acting at a minimum of three different kinetically defined steps. The action at two of these steps is dependent on BRD4 concentration, whereas the third step requires the association of BRD4 with P-TEFb. BRD4 is also found to bind to NELF-E, a component of the NELF complex. Unexpectedly, NELF-E modifies GR induction in a manner that is independent of the NELF complex. Several of the kinetically defined steps of BRD4 in this study are proposed to be related to its known biochemical actions. However, novel actions of BRD4 and of NELF-E in GR-controlled gene induction have been uncovered. The model-based competition assay is also unique in being able to order, for the first time, the sites of action of the various reaction components: GR < Cdk9 < BRD4 ≤ induced gene < NELF-E. This ability to order factor actions will assist efforts to reduce the side effects of steroid treatments. PMID:26504077

Effect of infliximab top-down therapy on weight gain in pediatric Crohns disease.

PubMed

Kim, Mi Jin; Lee, Woo Yong; Choi, Kyong Eun; Choe, Yon Ho

2012-12-01

This retrospective-medical-record review was conducted to evaluate effect of infliximab therapy, particularly with a top-down strategy, on the nutritional parameters of children with Crohns disease (CD). 42 patients who were diagnosed with Crohns disease at the Pediatric Gastroenterology center of a tertiary care teaching hospital and achieved remission at two months and one year after beginning of treatment were divided into four subgroups according to the treatment regimen; azathioprine group (n = 11), steroid group (n = 11), infliximab top-down group (n = 11) and step-up group (n = 9). Weight, height, and serum albumin were measured at diagnosis, and then at two months and one year after the initiation of treatment. At 2 months, the Z score increment for weight was highest in the steroid group, followed by the top-down, step-up, and azathioprine groups. At one year, the Z score increment was highest in top-down group, followed by steroid, azathioprine, and step-up group. There were no significant differences between the four groups in Z score increment for height and serum albumin during the study period. The top-down infliximab treatment resulted in superior outcome for weight gain, compared to the step-up therapy and other treatment regimens.

Growth temperature optimization of GaAs-based In0.83Ga0.17As on InxAl1-xAs buffers

NASA Astrophysics Data System (ADS)

Chen, X. Y.; Gu, Y.; Zhang, Y. G.; Ma, Y. J.; Du, B.; Zhang, J.; Ji, W. Y.; Shi, Y. H.; Zhu, Y.

2018-04-01

Improved quality of gas source molecular beam epitaxy grown In0.83Ga0.17As layer on GaAs substrate was achieved by adopting a two-step InxAl1-xAs metamorphic buffer at different temperatures. With a high-temperature In0.83Al0.17As template following a low-temperature composition continuously graded InxAl1-xAs (x = 0.05-0.86) buffer, better structural, optical and electrical properties of succeeding In0.83Ga0.17As were confirmed by atomic force microscopy, photoluminescence and Hall-effect measurements. Cross-sectional transmission electron microscopy revealed significant effect of the two-step temperature grown InAlAs buffer layers on the inhibition of threading dislocations due to the deposition of high density nuclei on GaAs substrate at the low growth temperature. The limited reduction for the dark current of GaAs-based In0.83Ga0.17As photodetectors on the two-step temperature grown InxAl1-xAs buffer layers was ascribed to the contribution of impurities caused by the low growth temperature of InAlAs buffers.

Molecular mechanism of ERK dephosphorylation by striatal-enriched protein tyrosine phosphatase (STEP)

PubMed Central

Li, Hui; Li, Kang-shuai; Su, Jing; Chen, Lai-Zhong; Xu, Yun-Fei; Wang, Hong-Mei; Gong, Zheng; Cui, Guo-Ying; Yu, Xiao; Wang, Kai; Yao, Wei; Xin, Tao; Li, Min-Yong; Xiao, Kun-Hong; An, Xiao-fei; Huo, Yuqing; Xu, Zhi-gang; Sun, Jin-Peng; Pang, Qi

2013-01-01

Striatal-enriched tyrosine phosphatase (STEP) is an important regulator of neuronal synaptic plasticity, and its abnormal level or activity contributes to cognitive disorders. One crucial downstream effector and direct substrate of STEP is extracellular signal-regulated protein kinase (ERK), which has important functions in spine stabilisation and action potential transmission. The inhibition of STEP activity toward phospho-ERK has the potential to treat neuronal diseases, but the detailed mechanism underlying the dephosphorylation of phospho-ERK by STEP is not known. Therefore, we examined STEP activity toward pNPP, phospho-tyrosine-containing peptides, and the full-length phospho-ERK protein using STEP mutants with different structural features. STEP was found to be a highly efficient ERK tyrosine phosphatase that required both its N-terminal regulatory region and key residues in its active site. Specifically, both KIM and KIS of STEP were required for ERK interaction. In addition to the N-terminal KIS region, S245, hydrophobic residues L249/L251, and basic residues R242/R243 located in the KIM region were important in controlling STEP activity toward phospho-ERK. Further kinetic experiments revealed subtle structural differences between STEP and HePTP that affected the interactions of their KIMs with ERK. Moreover, STEP recognised specific positions of a phospho-ERK peptide sequence through its active site, and the contact of STEP F311 with phospho-ERK V205 and T207 were crucial interactions. Taken together, our results not only provide the information for interactions between ERK and STEP, but will also help in the development of specific strategies to target STEP-ERK recognition, which could serve as a potential therapy for neurological disorders. PMID:24117863

Counting Steps in Activities of Daily Living in People With a Chronic Disease Using Nine Commercially Available Fitness Trackers: Cross-Sectional Validity Study

PubMed Central

Beekman, Emmylou; Theunissen, Kyra; Braun, Susy; Beurskens, Anna J

2018-01-01

Background Measuring physical activity with commercially available activity trackers is gaining popularity. People with a chronic disease can especially benefit from knowledge about their physical activity pattern in everyday life since sufficient physical activity can contribute to wellbeing and quality of life. However, no validity data are available for this population during activities of daily living. Objective The aim of this study was to investigate the validity of 9 commercially available activity trackers for measuring step count during activities of daily living in people with a chronic disease receiving physiotherapy. Methods The selected activity trackers were Accupedo (Corusen LLC), Activ8 (Remedy Distribution Ltd), Digi-Walker CW-700 (Yamax), Fitbit Flex (Fitbit inc), Lumoback (Lumo Bodytech), Moves (ProtoGeo Oy), Fitbit One (Fitbit inc), UP24 (Jawbone), and Walking Style X (Omron Healthcare Europe BV). In total, 130 persons with chronic diseases performed standardized activity protocols based on activities of daily living that were recorded on video camera and analyzed for step count (gold standard). The validity of the trackers’ step count was assessed by correlation coefficients, t tests, scatterplots, and Bland-Altman plots. Results The correlations between the number of steps counted by the activity trackers and the gold standard were low (range: –.02 to .33). For all activity trackers except for Fitbit One, a significant systematic difference with the gold standard was found for step count. Plots showed a wide range in scores for all activity trackers; Activ8 showed an average overestimation and the other 8 trackers showed underestimations. Conclusions This study showed that the validity of 9 commercially available activity trackers is low measuring steps while individuals with chronic diseases receiving physiotherapy engage in activities of daily living. PMID:29610110

Sexual dimorphism of the tibia in contemporary Greek-Cypriots and Cretans: Forensic applications.

PubMed

Kranioti, E K; García-Donas, J G; Almeida Prado, P S; Kyriakou, X P; Langstaff, H C

2017-02-01

Sex estimation is an essential step in the identification process of unknown heavily decomposed human remains as it eliminates all possible matches of the opposite sex from the missing person's database. Osteometric methods constitute a reliable approach for sex estimation and considering the variation of sexual dimorphism between and within populations; standards for specific populations are required to ensure accurate results. The current study aspires to contribute osteometric data on the tibia from contemporary Greek-Cypriots to assist the identification process. A secondary goal involves osteometric comparison with data from Crete, a Greek island with similar cultural and dietary customs and environmental conditions. Left tibiae from one hundred and thirty-two skeletons (70 males and 62 females) of Greek-Cypriots and one hundred and fifty-seven skeletons (85 males, 72 females) of Cretans were measured. Seven standard metric variables including Maximum length (ML), Upper epiphyseal breadth (UB), Nutrient foramen anteroposterior diameter (NFap), Nutrient Foramen transverse diameter (NFtrsv), Nutrient foramen circumference (NFCirc), Minimum circumference (MinCirc) and Lower epiphyseal breadth (LB) were compared between sexes and populations. Univariate and multivariate discriminant functions were developed and posterior probabilities were calculated for each sample. Results confirmed the existence of sexual dimorphism of the tibia in both samples as well as the pooled sample. Classification accuracy for univariate functions ranged from 78% to 85% for Greek-Cypriots and from 69% to 83% for Cretans. The best multivariate equations after cross-validation resulted in 87% for Greek-Cypriots and 90% accuracy for Cretans. When the samples were pooled accuracy reached 87% with over 95% confidence for about one third of the population. Estimates with over 95% of posterior probability can be considered reliable while any less than 80% should be treated with caution. This work constitutes the initial step towards the creation of an osteometric database for Greek-Cypriots and we hope it can contribute to the biological profiling and identification of the missing and to potential forensic cases of unknown skeletal remains both in Cyprus and Crete. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

APWPs: Critical Building Steps and Potential for Future Geodynamical Studies.

NASA Astrophysics Data System (ADS)

Besse, J.

2004-12-01

Among other items, the Apparent Polar Wander Paths (APWP) of individual tectonic blocks contain information on geodynamical events from both shallower lithospheric sources (e.g. continental breakups and collisions) and deeper mantle sources affected by convection. Recent advances in the Earth Sciences, such as provided by global tomography or climate modeling, have emphasized the essential need for accurate reconstructions of the Earth's surface (blocks, plates and their boundaries and topographies), in order for instance to compare the initial positions of downgoing slabs or emerging hot spots with deeper mantle features, or to understand why and how time-varying climates and biomes may be related. A half century after its initial pionneering contributions to the formulation of continental drift and plate tectonics, paleomagnetism remains an invaluable tool which will allow us to solve a very large range of problems concerning both internal and external geodynamics (solid, fluid and bio-spheres). The accurate determination of the APWPs of crustal and lithospheric blocks remains one of the main goals that must be pursued by the paleomagnetic community. Based on two examples, one extending from Permian to Present, the other in the Late Proterozoic to Early Paleozoic, I will discuss various aspects of the construction of APWPs and reconstruction of past plate positions. Critical steps involve: 1) how are original paleomagnetic data selected? 2) how are the kinematic models used to transfer data from one plate to the other determined ? 3) how can poles coming from deformed (e.g. rotated) regions be used ? and 4) how good is the geocentric axial dipole (GAD) assumption, which is fundamental for reliable plate reconstructions ? Particular emphasis will be given to this last topic, since the GAD hypothesis has recently been challenged, with suggestions that significant long-term octupolar contributions might have existed from the Precambrian throughout to the early Tertiary. These might account for the low inclinations observed in central Asia in the Cretaceous and early Tertiary, or for the misfits of Pangea (Pangea A or B?). GAD hypothesis appears to be essentially correct and APWPs still have a bright future.

Adaptive step-size algorithm for Fourier beam-propagation method with absorbing boundary layer of auto-determined width.

PubMed

Learn, R; Feigenbaum, E

2016-06-01

Two algorithms that enhance the utility of the absorbing boundary layer are presented, mainly in the framework of the Fourier beam-propagation method. One is an automated boundary layer width selector that chooses a near-optimal boundary size based on the initial beam shape. The second algorithm adjusts the propagation step sizes based on the beam shape at the beginning of each step in order to reduce aliasing artifacts.

Adaptive step-size algorithm for Fourier beam-propagation method with absorbing boundary layer of auto-determined width

DOE Office of Scientific and Technical Information (OSTI.GOV)

Learn, R.; Feigenbaum, E.

Two algorithms that enhance the utility of the absorbing boundary layer are presented, mainly in the framework of the Fourier beam-propagation method. One is an automated boundary layer width selector that chooses a near-optimal boundary size based on the initial beam shape. Furthermore, the second algorithm adjusts the propagation step sizes based on the beam shape at the beginning of each step in order to reduce aliasing artifacts.

Adaptive step-size algorithm for Fourier beam-propagation method with absorbing boundary layer of auto-determined width

DOE PAGES

Learn, R.; Feigenbaum, E.

2016-05-27

Two algorithms that enhance the utility of the absorbing boundary layer are presented, mainly in the framework of the Fourier beam-propagation method. One is an automated boundary layer width selector that chooses a near-optimal boundary size based on the initial beam shape. Furthermore, the second algorithm adjusts the propagation step sizes based on the beam shape at the beginning of each step in order to reduce aliasing artifacts.

Two-Step Incision for Periarterial Sympathectomy of the Hand.

PubMed

Jeon, Seung Bae; Ahn, Hee Chang; Ahn, Yong Su; Choi, Matthew Seung Suk

2015-11-01

Surgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire. A total of 40 patients (17 men and 23 women) with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS) and the Wake Forest University rating scale. The total patient score was 8.59 (range, 6-15) in the two-step incision group and 9.62 (range, 7-18) in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034) but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03). Compared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.

Effect of one-step polishing system on the color stability of nanocomposites.

PubMed

Alawjali, S S; Lui, J L

2013-08-01

This study was to compare the effect of three different one-step polishing systems on the color stability of three different types of nanocomposites after immersion in coffee for one day and seven days and determine which nanocomposite material has the best color stability following polishing with each of the one-step polishing system. The nanocomposites tested were Tetric EvoCeram, Grandio and Herculite Précis. A total of 120 discs (40/nanocomposite, 8mm×2mm) were fabricated. Ten specimens for each nanocomposite cured under Mylar strips served as the control. The other specimens were polished with OptraPol, OneGloss and Occlubrush immersed in coffee (Nescafé) up to seven days. Color measurements were made with a spectrophotometer at baseline and after one and seven days. Two way repeated measure ANOVA, two way ANOVA and Bonferroni tests were used for statistical analyses (P<0.05). The immersion time was a significant factor in the discoloration of the nanocomposites. The effect of three one-step polishing systems on the color stability was also significant. The color change values of the materials cured against Mylar strips were the greatest. The lowest mean color change values were from the Occlubrush polished groups. The effect of the three different types of nanocomposite on the color change was significant. The highest color change values were with Tetric EvoCeram groups. The lowest color change values were with Herculite Précis groups. The color change of nanocomposite resins is affected by the type of composite, polishing procedure and the period of immersion in the staining agent. Copyright © 2012 Elsevier Ltd. All rights reserved.

Constructing a self: the role of self-structure and self-certainty in social anxiety.

PubMed

Stopa, Lusia; Brown, Mike A; Luke, Michelle A; Hirsch, Colette R

2010-10-01

Current cognitive models stress the importance of negative self-perceptions in maintaining social anxiety, but focus predominantly on content rather than structure. Two studies examine the role of self-structure (self-organisation, self-complexity, and self-concept clarity) in social anxiety. In study one, self-organisation and self-concept clarity were correlated with social anxiety, and a step-wise multiple regression showed that after controlling for depression and self-esteem, which explained 35% of the variance in social anxiety scores, self-concept clarity uniquely predicted social anxiety and accounted for an additional 7% of the variance in social anxiety scores in an undergraduate sample (N=95) and the interaction between self-concept clarity and compartmentalisation (an aspect of evaluative self-organisation) at step 3 of the multiple regression accounted for a further 3% of the variance in social anxiety scores. In study two, high (n=26) socially anxious participants demonstrated less self-concept clarity than low socially anxious participants (n=26) on both self-report (used in study one) and on computerised measures of self-consistency and confidence in self-related judgments. The high socially anxious group had more compartmentalised self-organisation than the low anxious group, but there were no differences between the two groups on any of the other measures of self-organisation. Self-complexity did not contribute to social anxiety in either study, although this may have been due to the absence of a stressor. Overall, the results suggest that self-structure has a potentially important role in understanding social anxiety and that self-concept clarity and other aspects of self-structure such as compartmentalisation interact with each other and could be potential maintaining factors in social anxiety. Cognitive therapy for social phobia might influence self-structure, and understanding the role of structural variables in maintenance and treatment could eventually help to improve treatment outcome. Copyright 2010 Elsevier Ltd. All rights reserved.

Constructing a self: The role of self-structure and self-certainty in social anxiety

PubMed Central

Stopa, Lusia; Brown, Mike A.; Luke, Michelle A.; Hirsch, Colette R.

2010-01-01

Current cognitive models stress the importance of negative self-perceptions in maintaining social anxiety, but focus predominantly on content rather than structure. Two studies examine the role of self-structure (self-organisation, self-complexity, and self-concept clarity) in social anxiety. In study one, self-organisation and self-concept clarity were correlated with social anxiety, and a step-wise multiple regression showed that after controlling for depression and self-esteem, which explained 35% of the variance in social anxiety scores, self-concept clarity uniquely predicted social anxiety and accounted for an additional 7% of the variance in social anxiety scores in an undergraduate sample (N = 95) and the interaction between self-concept clarity and compartmentalisation (an aspect of evaluative self-organisation) at step 3 of the multiple regression accounted for a further 3% of the variance in social anxiety scores. In study two, high (n = 26) socially anxious participants demonstrated less self-concept clarity than low socially anxious participants (n = 26) on both self-report (used in study one) and on computerised measures of self-consistency and confidence in self-related judgments. The high socially anxious group had more compartmentalised self-organisation than the low anxious group, but there were no differences between the two groups on any of the other measures of self-organisation. Self-complexity did not contribute to social anxiety in either study, although this may have been due to the absence of a stressor. Overall, the results suggest that self-structure has a potentially important role in understanding social anxiety and that self-concept clarity and other aspects of self-structure such as compartmentalisation interact with each other and could be potential maintaining factors in social anxiety. Cognitive therapy for social phobia might influence self-structure, and understanding the role of structural variables in maintenance and treatment could eventually help to improve treatment outcome. PMID:20800751

Results of a prospective clinical study on the diagnostic performance of standard magnetic resonance imaging in comparison to a combination of 3T MRI and additional CT imaging in Kienböck's disease.

PubMed

Stahl, Stephane; Hentschel, Pascal; Ketelsen, Dominik; Grosse, Ulrich; Held, Manuel; Wahler, Theodora; Syha, Roland; Schaller, Hans-Eberhard; Nikolaou, Konstantin; Grözinger, Gerd

2017-05-01

This prospective clinical study examined standard wrist magnetic resonance imaging (MRI) examinations and the incremental value of computed tomography (CT) in the diagnosis of Kienböck's disease (KD) with regard to reliability and precision in the different diagnostic steps during diagnostic work-up. Sixty-four consecutive patients referred between January 2009 and January 2014 with positive initial suspicion of KD according to external standard wrist MRI were prospectively included (step one). Institutional review board approval was obtained. Clinical examination by two handsurgeons were followed by wrist radiographs (step two), ultrathin-section CT, and 3T contrast-enhanced MRI (step three). Final diagnosis was established in a consensus conference involving all examiners and all examinations results available from step three. In 12/64 patients, initial suspicion was discarded at step two and in 34/64 patients, the initial suspicion of KD was finally discarded at step three. The final external MRI positive predictive value was 47%. The most common differential diagnoses at step three were intraosseous cysts (n=15), lunate pseudarthrosis (n=13), and ulnar impaction syndrome (n=5). A correlation between radiograph-based diagnoses (step two) with final diagnosis (step three) showed that initial suspicion of stage I KD had the lowest sensitivity for correct diagnosis (2/11). Technical factors associated with a false positive external MRI KD diagnosis were not found. Standard wrist MRI should be complemented with thin-section CT, and interdisciplinary interpretation of images and clinical data, to increase diagnostic accuracy in patients with suspected KD. Copyright © 2017. Published by Elsevier B.V.

Georges Lemaître: The Priest Who Invented the Big Bang

NASA Astrophysics Data System (ADS)

Lambert, Dominique

This contribution gives a concise survey of Georges Lemaître works and life, shedding some light on less-known aspects. Lemaître is a Belgian catholic priest who gave for the first time in 1927 the explanation of the Hubble law and who proposed in 1931 the "Primeval Atom Hypothesis", considered as the first step towards the Big Bang cosmology. But the scientific work of Lemaître goes far beyond Physical Cosmology. Indeed, he contributed also to the theory of Cosmis Rays, to the Spinor theory, to Analytical mechanics (regularization of 3- Bodies problem), to Numerical Analysis (Fast Fourier Transform), to Computer Science (he introduced and programmed the first computer of Louvain),… Lemaître took part to the "Science and Faith" debate. He defended a position that has some analogy with the NOMA principle, making a sharp distinction between what he called the "two paths to Truth" (a scientific one and a theological one). In particular, he never made a confusion between the theological concept of "creation" and the scientific notion of "natural beginning" (initial singularity). Lemaître was deeply rooted in his faith and sacerdotal vocation. Remaining a secular priest, he belonged to a community of priests called "The Friends of Jesus", characterized by a deep spirituality and special vows (for example the vow of poverty). He had also an apostolic activity amongst Chinese students.

Patterns of control of maximum metabolic rate in humans.

PubMed

Hochachka, Peter W; Beatty, Cheryl L

2003-09-01

In this analysis, four performance phenotypes were used to compare mechanisms of control of aerobic maximum metabolic rate (MMR): (i) untrained sedentary (US) subjects, as a reference group against which to compare (ii) power trained (PT), (iii) endurance trained (ET) and (iv) high altitude adapted native (HA) subject groups. Sprinters represented the PT group; long distance runners illustrated the ET group; and Quechuas represented the HA group. Numerous recent studies have identified contributors to control on both the adenosine triphosphate (ATP) supply side and the ATP demand side of ATP turnover. Control coefficients or c(i) values were defined as fractional change in MMR/fractional change in the capacity of any given step in ATP turnover. From the best available evidence it appears that at MMR all five of the major steps in energy delivery (namely, ventilation, pulmonary diffusion, cardiac output, tissue capillary - mitochondrial O(2) transfer, and aerobic cell metabolism per se) approach an upper functional ceiling, with control strength being distributed amongst the various O(2) flux steps. On the energy demand side, the situation is somewhat simplified since at MMR approximately 90% of O(2)-based ATP synthesis is used for actomyosin (AM) and Ca(2+) ATPases; at MMR these two ATP demand rates also appear to be near an upper functional ceiling. In consequence, at MMR the control contributions or c(i) values are rather evenly divided amongst all seven major steps in ATP supply and ATP demand pathways right to the point of fatigue. Relative to US (the reference group), in PT subjects at MMR control strength shifts towards O(2) delivery steps (ventilation, pulmonary diffusion and cardiac output). In contrast in ET and HA subjects at MMR control shifts towards the energy demand steps (AM and Ca(2+) ATPases), and more control strength is focussed on tissue level ATP supply and ATP demand. One obvious advantage of the ET and HA control pattern is improved metabolite homeostasis. Another possibility is that, with some reserve capacity in the O(2) delivery steps and control focussed on ATP turnover at the tissue level, nature has designed the ideal 'endurance machine'.

Control of maximum metabolic rate in humans: dependence on performance phenotypes.

PubMed

Hochachka, Peter W; Burelle, Yan

2004-01-01

Borrowing from metabolic control analysis the concept of control coefficients or ci values, defined as fractional change in MMR/fractional change in the capacity of any given step in ATP turnover, we used four performance phenotypes to compare mechanisms of control of aerobic maximum metabolic rate (MMR): (i) untrained sedentary (US) subjects, as a reference group against which to compare (ii) power trained (PT), (iii) endurance trained (ET), and (iv) high altitude adapted native (HA) subject groups. Sprinters represented the PT group; long distance runners illustrated the ET group; and Andean natives represented the HA group. Numerous recent studies have identified contributors to control on both the adenosine triphosphate (ATP) supply side and the ATP demand side of ATP turnover. From the best available evidence it appears that at MMR all five of the major steps in energy delivery (namely, ventilation, pulmonary diffusion, cardiac output, tissue capillary--mitochondrial O2 transfer, and aerobic cell metabolism per se) approach an upper functional ceiling, with control strength being distributed amongst the various O2 flux steps. On the energy demand side, the situation is somewhat simplified since at MMR approximately 90% of O2-based ATP synthesis is used for actomyosin (AM) and Ca2+ ATPases; at MMR these two ATP demand rates also appear to be near an upper functional ceiling. In consequence, at MMR the control contributions or ci values are distributed amongst all seven major steps in ATP supply and ATP demand pathways right to the point of fatigue. Relative to US (the reference group), in PT subjects at MMR control strength shifts towards O2 delivery steps (ventilation, pulmonary diffusion, and cardiac output); here physiological regulation clearly dominates MMR control. In contrast in ET and HA subjects at MMR control shifts towards the energy demand steps (AM and Ca2+ ATPases), and more control strength is focussed on tissue level ATP supply and ATP demand. One obvious advantage of the ET and HA biochemical-level control is improved metabolite homeostasis. Additionally, with some reserve capacity in the O2 delivery steps, the focussing of control on ATP turnover at the tissue level has allowed nature to improve on an 'endurance machine' design.

Detection of Heterogeneous Small Inclusions by a Multi-Step MUSIC Method

NASA Astrophysics Data System (ADS)

Solimene, Raffaele; Dell'Aversano, Angela; Leone, Giovanni

2014-05-01

In this contribution the problem of detecting and localizing scatterers with small (in terms of wavelength) cross sections by collecting their scattered field is addressed. The problem is dealt with for a two-dimensional and scalar configuration where the background is given as a two-layered cylindrical medium. More in detail, while scattered field data are taken in the outermost layer, inclusions are embedded within the inner layer. Moreover, the case of heterogeneous inclusions (i.e., having different scattering coefficients) is addressed. As a pertinent applicative context we identify the problem of diagnose concrete pillars in order to detect and locate rebars, ducts and other small in-homogeneities that can populate the interior of the pillar. The nature of inclusions influences the scattering coefficients. For example, the field scattered by rebars is stronger than the one due to ducts. Accordingly, it is expected that the more weakly scattering inclusions can be difficult to be detected as their scattered fields tend to be overwhelmed by those of strong scatterers. In order to circumvent this problem, in this contribution a multi-step MUltiple SIgnal Classification (MUSIC) detection algorithm is adopted [1]. In particular, the first stage aims at detecting rebars. Once rebars have been detected, their positions are exploited to update the Green's function and to subtract the scattered field due to their presence. The procedure is repeated until all the inclusions are detected. The analysis is conducted by numerical experiments for a multi-view/multi-static single-frequency configuration and the synthetic data are generated by a FDTD forward solver. Acknowledgement This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar." [1] R. Solimene, A. Dell'Aversano and G. Leone, "MUSIC algorithms for rebar detection," J. of Geophysics and Engineering, vol. 10, pp. 1-8, 2013

A Mixed Approach to Similarity Metric Selection in Affinity Propagation-Based WiFi Fingerprinting Indoor Positioning.

PubMed

Caso, Giuseppe; de Nardis, Luca; di Benedetto, Maria-Gabriella

2015-10-30

The weighted k-nearest neighbors (WkNN) algorithm is by far the most popular choice in the design of fingerprinting indoor positioning systems based on WiFi received signal strength (RSS). WkNN estimates the position of a target device by selecting k reference points (RPs) based on the similarity of their fingerprints with the measured RSS values. The position of the target device is then obtained as a weighted sum of the positions of the k RPs. Two-step WkNN positioning algorithms were recently proposed, in which RPs are divided into clusters using the affinity propagation clustering algorithm, and one representative for each cluster is selected. Only cluster representatives are then considered during the position estimation, leading to a significant computational complexity reduction compared to traditional, flat WkNN. Flat and two-step WkNN share the issue of properly selecting the similarity metric so as to guarantee good positioning accuracy: in two-step WkNN, in particular, the metric impacts three different steps in the position estimation, that is cluster formation, cluster selection and RP selection and weighting. So far, however, the only similarity metric considered in the literature was the one proposed in the original formulation of the affinity propagation algorithm. This paper fills this gap by comparing different metrics and, based on this comparison, proposes a novel mixed approach in which different metrics are adopted in the different steps of the position estimation procedure. The analysis is supported by an extensive experimental campaign carried out in a multi-floor 3D indoor positioning testbed. The impact of similarity metrics and their combinations on the structure and size of the resulting clusters, 3D positioning accuracy and computational complexity are investigated. Results show that the adoption of metrics different from the one proposed in the original affinity propagation algorithm and, in particular, the combination of different metrics can significantly improve the positioning accuracy while preserving the efficiency in computational complexity typical of two-step algorithms.

A Mixed Approach to Similarity Metric Selection in Affinity Propagation-Based WiFi Fingerprinting Indoor Positioning

PubMed Central

Caso, Giuseppe; de Nardis, Luca; di Benedetto, Maria-Gabriella

2015-01-01

The weighted k-nearest neighbors (WkNN) algorithm is by far the most popular choice in the design of fingerprinting indoor positioning systems based on WiFi received signal strength (RSS). WkNN estimates the position of a target device by selecting k reference points (RPs) based on the similarity of their fingerprints with the measured RSS values. The position of the target device is then obtained as a weighted sum of the positions of the k RPs. Two-step WkNN positioning algorithms were recently proposed, in which RPs are divided into clusters using the affinity propagation clustering algorithm, and one representative for each cluster is selected. Only cluster representatives are then considered during the position estimation, leading to a significant computational complexity reduction compared to traditional, flat WkNN. Flat and two-step WkNN share the issue of properly selecting the similarity metric so as to guarantee good positioning accuracy: in two-step WkNN, in particular, the metric impacts three different steps in the position estimation, that is cluster formation, cluster selection and RP selection and weighting. So far, however, the only similarity metric considered in the literature was the one proposed in the original formulation of the affinity propagation algorithm. This paper fills this gap by comparing different metrics and, based on this comparison, proposes a novel mixed approach in which different metrics are adopted in the different steps of the position estimation procedure. The analysis is supported by an extensive experimental campaign carried out in a multi-floor 3D indoor positioning testbed. The impact of similarity metrics and their combinations on the structure and size of the resulting clusters, 3D positioning accuracy and computational complexity are investigated. Results show that the adoption of metrics different from the one proposed in the original affinity propagation algorithm and, in particular, the combination of different metrics can significantly improve the positioning accuracy while preserving the efficiency in computational complexity typical of two-step algorithms. PMID:26528984

A high-order relaxation method with projective integration for solving nonlinear systems of hyperbolic conservation laws

NASA Astrophysics Data System (ADS)

Lafitte, Pauline; Melis, Ward; Samaey, Giovanni

2017-07-01

We present a general, high-order, fully explicit relaxation scheme which can be applied to any system of nonlinear hyperbolic conservation laws in multiple dimensions. The scheme consists of two steps. In a first (relaxation) step, the nonlinear hyperbolic conservation law is approximated by a kinetic equation with stiff BGK source term. Then, this kinetic equation is integrated in time using a projective integration method. After taking a few small (inner) steps with a simple, explicit method (such as direct forward Euler) to damp out the stiff components of the solution, the time derivative is estimated and used in an (outer) Runge-Kutta method of arbitrary order. We show that, with an appropriate choice of inner step size, the time step restriction on the outer time step is similar to the CFL condition for the hyperbolic conservation law. Moreover, the number of inner time steps is also independent of the stiffness of the BGK source term. We discuss stability and consistency, and illustrate with numerical results (linear advection, Burgers' equation and the shallow water and Euler equations) in one and two spatial dimensions.

Multiple dual mode counter-current chromatography with variable duration of alternating phase elution steps.

PubMed

Kostanyan, Artak E; Erastov, Andrey A; Shishilov, Oleg N

2014-06-20

The multiple dual mode (MDM) counter-current chromatography separation processes consist of a succession of two isocratic counter-current steps and are characterized by the shuttle (forward and back) transport of the sample in chromatographic columns. In this paper, the improved MDM method based on variable duration of alternating phase elution steps has been developed and validated. The MDM separation processes with variable duration of phase elution steps are analyzed. Basing on the cell model, analytical solutions are developed for impulse and non-impulse sample loading at the beginning of the column. Using the analytical solutions, a calculation program is presented to facilitate the simulation of MDM with variable duration of phase elution steps, which can be used to select optimal process conditions for the separation of a given feed mixture. Two options of the MDM separation are analyzed: 1 - with one-step solute elution: the separation is conducted so, that the sample is transferred forward and back with upper and lower phases inside the column until the desired separation of the components is reached, and then each individual component elutes entirely within one step; 2 - with multi-step solute elution, when the fractions of individual components are collected in over several steps. It is demonstrated that proper selection of the duration of individual cycles (phase flow times) can greatly increase the separation efficiency of CCC columns. Experiments were carried out using model mixtures of compounds from the GUESSmix with solvent systems hexane/ethyl acetate/methanol/water. The experimental results are compared to the predictions of the theory. A good agreement between theory and experiment has been demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessment of biological, psychological and adherence factors in the prediction of step-down treatment for patients with well-controlled asthma.

PubMed

Saito, N; Kamata, A; Itoga, M; Tamaki, M; Kayaba, H; Ritz, T

2017-04-01

Inhaled corticosteroids (ICS) and inhaled corticosteroids combined with long-acting beta2-agonist (ICS/LABA) are standard treatments for asthma. However, factors that might help reduce medication in well-controlled asthma are unknown. We classified problems of asthma patients into biological, psychological and adherence factors, and investigated factors associated with the indication and failure of a medication step-down treatment. Two hundred twenty two well-controlled asthma patients receiving ICS or ICS/LABA were assessed for physical and psychiatric problems and followed up for one year from adjustment of their treatment step. Factor B was defined as a presence of chronic upper airway complications. Factor P was defined as presence of psychiatric complications such as sleep disorder, depression, anxiety and somatoform disorders. Factor A was defined as poor adherence to ICS or ICS/LABA inhaler of 75% or less. Success in step-down treatment was defined as maintenance of well-controlled status for over one year after step-down. Factor B was the most important single negative predictive factor for indication for step-down treatment (Odds ratio; 0.19). Factor A increased the risk of failure to maintain step-down treatment most significantly by 23-fold, and factor B increased it by 11-fold. The combination of factors B and A increased failure by 24-fold, factors P and A by 21-fold, all three factors by 36-fold. Factor P only interacted with the other factors to reduce chances of stepping down, but did not constitute a problem factor when present alone. The evaluation of biological, psychological and adherence problems may lead to a more proactive and targeted approach to step-down treatment for patients with well-controlled asthma. © 2017 John Wiley & Sons Ltd.

Two methods to simulate intrapulpal pressure: effects upon bonding performance of self-etch adhesives.

PubMed

Feitosa, V P; Gotti, V B; Grohmann, C V; Abuná, G; Correr-Sobrinho, L; Sinhoreti, M A C; Correr, A B

2014-09-01

To evaluate the effects of two methods to simulate physiological pulpal pressure on the dentine bonding performance of two all-in-one adhesives and a two-step self-etch silorane-based adhesive by means of microtensile bond strength (μTBS) and nanoleakage surveys. The self-etch adhesives [G-Bond Plus (GB), Adper Easy Bond (EB) and silorane adhesive (SIL)] were applied to flat deep dentine surfaces from extracted human molars. The restorations were constructed using resin composites Filtek Silorane or Filtek Z350 (3M ESPE). After 24 h using the two methods of simulated pulpal pressure or no pulpal pressure (control groups), the bonded teeth were cut into specimens and submitted to μTBS and silver uptake examination. Results were analysed with two-way anova and Tukey's test (P < 0.05). Both methods of simulated pulpal pressure led statistically similar μTBS for all adhesives. No difference between control and pulpal pressure groups was found for SIL and GB. EB led significant drop (P = 0.002) in bond strength under pulpal pressure. Silver impregnation was increased after both methods of simulated pulpal pressure for all adhesives, and it was similar between the simulated pulpal pressure methods. The innovative method to simulate pulpal pressure behaved similarly to the classic one and could be used as an alternative. The HEMA-free one-step and the two-step self-etch adhesives had acceptable resistance against pulpal pressure, unlike the HEMA-rich adhesive. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Analyzing angular distributions for two-step dissociation mechanisms in velocity map imaging.

PubMed

Straus, Daniel B; Butler, Lynne M; Alligood, Bridget W; Butler, Laurie J

2013-08-15

Increasingly, velocity map imaging is becoming the method of choice to study photoinduced molecular dissociation processes. This paper introduces an algorithm to analyze the measured net speed, P(vnet), and angular, β(vnet), distributions of the products from a two-step dissociation mechanism, where the first step but not the second is induced by absorption of linearly polarized laser light. Typically, this might be the photodissociation of a C-X bond (X = halogen or other atom) to produce an atom and a momentum-matched radical that has enough internal energy to subsequently dissociate (without the absorption of an additional photon). It is this second step, the dissociation of the unstable radicals, that one wishes to study, but the measured net velocity of the final products is the vector sum of the velocity imparted to the radical in the primary photodissociation (which is determined by taking data on the momentum-matched atomic cophotofragment) and the additional velocity vector imparted in the subsequent dissociation of the unstable radical. The algorithm allows one to determine, from the forward-convolution fitting of the net velocity distribution, the distribution of velocity vectors imparted in the second step of the mechanism. One can thus deduce the secondary velocity distribution, characterized by a speed distribution P(v1,2°) and an angular distribution I(θ2°), where θ2° is the angle between the dissociating radical's velocity vector and the additional velocity vector imparted to the product detected from the subsequent dissociation of the radical.

Organic thin film transistor with a simplified planar structure

NASA Astrophysics Data System (ADS)

Zhang, Lei; Yu, Jungsheng; Zhong, Jian; Jiang, Yadong

2009-05-01

Organic thin film transistor (OTFT) with a simplified planar structure is described. The gate electrode and the source/drain electrodes of OTFT are processed in one planar structure. And these three electrodes are deposited on the glass substrate by DC sputtering technology using Cr/Ni target. Then the electrode layouts of different width length ratio are made by photolithography technology at the same time. Only one step of deposition and one step of photolithography is needed while conventional process takes at least two steps of deposition and two steps of photolithography. Metal is first prepared on the other side of glass substrate and electrode is formed by photolithography. Then source/drain electrode is prepared by deposition and photolithography on the side with the insulation layer. Compared to conventional process of OTFTs, the process in this work is simplified. After three electrodes prepared, the insulation layer is made by spin coating method. The organic material of polyimide is used as the insulation layer. A small molecular material of pentacene is evaporated on the insulation layer using vacuum deposition as the active layer. The process of OTFTs needs only three steps totally. A semi-auto probe stage is used to connect the three electrodes and the probe of the test instrument. A charge carrier mobility of 0.3 cm2 /V s, is obtained from OTFTs on glass substrates with and on/off current ratio of 105. The OTFTs with the planar structure using simplified process can simplify the device process and reduce the fabrication cost.

Probabilistic Plan Management

DTIC Science & Technology

2009-11-17

set of chains , the step adds scheduled methods that have an a priori likelihood of a failure outcome (Lines 3-5). It identifies the max eul value of the...activity meeting its objective, as well as its expected contribution to the schedule. By explicitly calculating these values , PADS is able to summarize the...variables. One of the main difficulties of this model is convolving the probability density functions and value functions while solving the model; this

Role of Thermochemical Decomposition in Energetic Material Initiation Sensitivity and Explosive Performance

DTIC Science & Technology

2007-02-05

Electronic excitation has been suggested as one contributing mechanistic step in a multiprocess detonation model [18], and such electronic...and, (b) Dick, J. J., Orientation Dependence of the Shock Initiation Sensitivity of PETN: A Steric Hindrance Model , Workshop on Desensitization of...Explosives and Propellants, Rijswijk, The Netherlands, 11-13 Nov 1991. [15] Piermarini, G. J., Block, S., Miller , P. J., Effects of Pressure on

Rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester.

PubMed

Tian, Zhe; Zhang, Yu; Li, Yuyou; Chi, Yongzhi; Yang, Min

2015-02-01

The purpose of this study was to explore how fast the thermophilic anaerobic microbial community could be established during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. Stable thermophilic anaerobic digestion was achieved within 20 days from a mesophilic digester treating sewage sludge by adopting the one-step startup strategy. The succession of archaeal and bacterial populations over a period of 60 days after the temperature increment was followed by using 454-pyrosequencing and quantitative PCR. After the increase of temperature, thermophilic methanogenic community was established within 11 days, which was characterized by the fast colonization of Methanosarcina thermophila and two hydrogenotrophic methanogens (Methanothermobacter spp. and Methanoculleus spp.). At the same time, the bacterial community was dominated by Fervidobacterium, whose relative abundance rapidly increased from 0 to 28.52 % in 18 days, followed by other potential thermophilic genera, such as Clostridium, Coprothermobacter, Anaerobaculum and EM3. The above result demonstrated that the one-step startup strategy could allow the rapid establishment of the thermophilic anaerobic microbial community. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of age and step length on joint kinetics during stepping task.

PubMed

Bieryla, Kathleen A; Buffinton, Christine

2015-07-16

Following a balance perturbation, a stepping response is commonly used to regain support, and the distance of the recovery step can vary. To date, no other studies have examined joint kinetics in young and old adults during increasing step distances, when participants are required to bring their rear foot forward. Therefore, the purpose of this study was to examine age-related differences in joint kinetics with increasing step distance. Twenty young and 20 old adults completed the study. Participants completed a step starting from double support, at an initial distance equal to the individual's average step length. The distance was increased by 10% body height until an unsuccessful attempt. A one-way, repeated measures ANOVA was used to determine the effects of age on joint kinetics during the maximum step distance. A two-way, repeated measures, mixed model ANOVA was used to determine the effects of age, step distance, and their interaction on joint kinetics during the first three step distances for all participants. Young adults completed a significantly longer step than old adults. During the maximum step, in general, kinetic measures were greater in the young than in the old. As step distance increased, all but one kinetic measure increased for both young and old adults. This study has shown the ability to discriminate between young and old adults, and could potentially be used in the future to distinguish between fallers and non-fallers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carbon Disulfide (CS2) Mechanisms in Formation of Atmospheric Carbon Dioxide (CO2) Formation from Unconventional Shale Gas Extraction and Processing Operations and Global Climate Change.

PubMed

Rich, Alisa L; Patel, Jay T

2015-01-01

Carbon disulfide (CS2) has been historically associated with the production of rayon, cellophane, and carbon tetrachloride. This study identifies multiple mechanisms by which CS2 contributes to the formation of CO2 in the atmosphere. CS2 and other associated sulfide compounds were found by this study to be present in emissions from unconventional shale gas extraction and processing (E&P) operations. The breakdown products of CS2; carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) are indirect greenhouse gases (GHGs) that contribute to CO2 levels in the atmosphere. The heat-trapping nature of CO2 has been found to increase the surface temperature, resulting in regional and global climate change. The purpose of this study is to identify five mechanisms by which CS2 and the breakdown products of CS2 contribute to atmospheric concentrations of CO2. The five mechanisms of CO2 formation are as follows: Chemical Interaction of CS2 and hydrogen sulfide (H2S) present in natural gas at high temperatures, resulting in CO2 formation;Combustion of CS2 in the presence of oxygen producing SO2 and CO2;Photolysis of CS2 leading to the formation of COS, CO, and SO2, which are indirect contributors to CO2 formation;One-step hydrolysis of CS2, producing reactive intermediates and ultimately forming H2S and CO2;Two-step hydrolysis of CS2 forming the reactive COS intermediate that reacts with an additional water molecule, ultimately forming H2S and CO2. CS2 and COS additionally are implicated in the formation of SO2 in the stratosphere and/or troposphere. SO2 is an indirect contributor to CO2 formation and is implicated in global climate change.

Tracking control of air-breathing hypersonic vehicles with non-affine dynamics via improved neural back-stepping design.

PubMed

Bu, Xiangwei; He, Guangjun; Wang, Ke

2018-04-01

This study considers the design of a new back-stepping control approach for air-breathing hypersonic vehicle (AHV) non-affine models via neural approximation. The AHV's non-affine dynamics is decomposed into velocity subsystem and altitude subsystem to be controlled separately, and robust adaptive tracking control laws are developed using improved back-stepping designs. Neural networks are applied to estimate the unknown non-affine dynamics, which guarantees the addressed controllers with satisfactory robustness against uncertainties. In comparison with the existing control methodologies, the special contributions are that the non-affine issue is handled by constructing two low-pass filters based on model transformations, and virtual controllers are treated as intermediate variables such that they aren't needed for back-stepping designs any more. Lyapunov techniques are employed to show the uniformly ultimately boundedness of all closed-loop signals. Finally, simulation results are presented to verify the tracking performance and superiorities of the investigated control strategy. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Feasibility of Focused Stepping Practice During Inpatient Rehabilitation Poststroke and Potential Contributions to Mobility Outcomes.

PubMed

Hornby, T George; Holleran, Carey L; Leddy, Abigail L; Hennessy, Patrick; Leech, Kristan A; Connolly, Mark; Moore, Jennifer L; Straube, Donald; Lovell, Linda; Roth, Elliot

2015-01-01

Optimal physical therapy strategies to maximize locomotor function in patients early poststroke are not well established. Emerging data indicate that substantial amounts of task-specific stepping practice may improve locomotor function, although stepping practice provided during inpatient rehabilitation is limited (<300 steps/session). The purpose of this investigation was to determine the feasibility of providing focused stepping training to patients early poststroke and its potential association with walking and other mobility outcomes. Daily stepping was recorded on 201 patients <6 months poststroke (80% < 1 month) during inpatient rehabilitation following implementation of a focused training program to maximize stepping practice during clinical physical therapy sessions. Primary outcomes included distance and physical assistance required during a 6-minute walk test (6MWT) and balance using the Berg Balance Scale (BBS). Retrospective data analysis included multiple regression techniques to evaluate the contributions of demographics, training activities, and baseline motor function to primary outcomes at discharge. Median stepping activity recorded from patients was 1516 steps/d, which is 5 to 6 times greater than that typically observed. The number of steps per day was positively correlated with both discharge 6MWT and BBS and improvements from baseline (changes; r = 0.40-0.87), independently contributing 10% to 31% of the total variance. Stepping activity also predicted level of assistance at discharge and discharge location (home vs other facility). Providing focused, repeated stepping training was feasible early poststroke during inpatient rehabilitation and was related to mobility outcomes. Further research is required to evaluate the effectiveness of these training strategies on short- or long-term mobility outcomes as compared with conventional interventions. © The Author(s) 2015.

Synthesis of Ultrathin Si Nanosheets from Natural Clays for Lithium-Ion Battery Anodes.

PubMed

Ryu, Jaegeon; Hong, Dongki; Choi, Sinho; Park, Soojin

2016-02-23

Two-dimensional Si nanosheets have been studied as a promising candidate for lithium-ion battery anode materials. However, Si nanosheets reported so far showed poor cycling performances and required further improvements. In this work, we utilize inexpensive natural clays for preparing high quality Si nanosheets via a one-step simultaneous molten salt-induced exfoliation and chemical reduction process. This approach produces high purity mesoporous Si nanosheets in high yield. As a control experiment, two-step process (pre-exfoliated silicate sheets and subsequent chemical reduction) cannot sustain their original two-dimensional structure. In contrast, one-step method results in a production of 5 nm-thick highly porous Si nanosheets. Carbon-coated Si nanosheet anodes exhibit a high reversible capacity of 865 mAh g(-1) at 1.0 A g(-1) with an outstanding capacity retention of 92.3% after 500 cycles. It also delivers high rate capability, corresponding to a capacity of 60% at 20 A g(-1) compared to that of 2.0 A g(-1). Furthermore, the Si nanosheet electrodes show volume expansion of only 42% after 200 cycles.

Identification of Candidate Genes for Reactivity in Guzerat (Bos indicus) Cattle: A Genome-Wide Association Study

PubMed Central

Fonseca, Pablo Augusto de Souza; Pires, Maria de Fátima Ávila; Ventura, Ricardo Vieira; Rosse, Izinara da Cruz.; Bruneli, Frank Angelo Tomita; Machado, Marco Antonio; Carvalho, Maria Raquel Santos

2017-01-01

Temperament is fundamental to animal production due to its direct influence on the animal-herdsman relationship. When compared to calm animals, the aggressive, anxious or fearful ones exhibit less weight gain, lower reproductive efficiency, decreased milk production and higher herd maintenance costs, all of which contribute to reduced profits. However, temperament is a trait that is complex and difficult to assess. Recently, a new quantitative system, REATEST®, for assessing reactivity, a phenotype of temperament, was developed. Herein, we describe the results of a Genome-wide association study for reactivity, assessed using REATEST® with a sample of 754 females from five dual-purpose (milk and meat production) Guzerat (Bos indicus) herds. Genotyping was performed using a 50k SNP chip and a two-step mixed model approach (Grammar-Gamma) with a one-by-one marker regression was used to identify QTLs. QTLs for reactivity were identified on chromosomes BTA1, BTA5, BTA14, and BTA25. Five intronic and two intergenic markers were significantly associated with reactivity. POU1F1, DRD3, VWA3A, ZBTB20, EPHA6, SNRPF and NTN4 were identified as candidate genes. Previous QTL reports for temperament traits, covering areas surrounding the SNPs/genes identified here, further corroborate these associations. The seven genes identified in the present study explain 20.5% of reactivity variance and give a better understanding of temperament biology. PMID:28125592

On the Least-Squares Fitting of Correlated Data: a Priorivs a PosterioriWeighting

NASA Astrophysics Data System (ADS)

Tellinghuisen, Joel

1996-10-01

One of the methods in common use for analyzing large data sets is a two-step procedure, in which subsets of the full data are first least-squares fitted to a preliminary set of parameters, and the latter are subsequently merged to yield the final parameters. The second step of this procedure is properly a correlated least-squares fit and requires the variance-covariance matrices from the first step to construct the weight matrix for the merge. There is, however, an ambiguity concerning the manner in which the first-step variance-covariance matrices are assessed, which leads to different statistical properties for the quantities determined in the merge. The issue is one ofa priorivsa posterioriassessment of weights, which is an application of what was originally calledinternalvsexternal consistencyby Birge [Phys. Rev.40,207-227 (1932)] and Deming ("Statistical Adjustment of Data." Dover, New York, 1964). In the present work the simplest case of a merge fit-that of an average as obtained from a global fit vs a two-step fit of partitioned data-is used to illustrate that only in the case of a priori weighting do the results have the usually expected and desired statistical properties: normal distributions for residuals,tdistributions for parameters assessed a posteriori, and χ2distributions for variances.

Arbitrary-step randomly delayed robust filter with application to boost phase tracking

NASA Astrophysics Data System (ADS)

Qin, Wutao; Wang, Xiaogang; Bai, Yuliang; Cui, Naigang

2018-04-01

The conventional filters such as extended Kalman filter, unscented Kalman filter and cubature Kalman filter assume that the measurement is available in real-time and the measurement noise is Gaussian white noise. But in practice, both two assumptions are invalid. To solve this problem, a novel algorithm is proposed by taking the following four steps. At first, the measurement model is modified by the Bernoulli random variables to describe the random delay. Then, the expression of predicted measurement and covariance are reformulated, which could get rid of the restriction that the maximum number of delay must be one or two and the assumption that probabilities of Bernoulli random variables taking the value one are equal. Next, the arbitrary-step randomly delayed high-degree cubature Kalman filter is derived based on the 5th-degree spherical-radial rule and the reformulated expressions. Finally, the arbitrary-step randomly delayed high-degree cubature Kalman filter is modified to the arbitrary-step randomly delayed high-degree cubature Huber-based filter based on the Huber technique, which is essentially an M-estimator. Therefore, the proposed filter is not only robust to the randomly delayed measurements, but robust to the glint noise. The application to the boost phase tracking example demonstrate the superiority of the proposed algorithms.

Synthesis of antiviral tetrahydrocarbazole derivatives by photochemical and acid-catalyzed C-H functionalization via intermediate peroxides (CHIPS).

PubMed

Gulzar, Naeem; Klussmann, Martin

2014-06-20

The direct functionalization of C-H bonds is an important and long standing goal in organic chemistry. Such transformations can be very powerful in order to streamline synthesis by saving steps, time and material compared to conventional methods that require the introduction and removal of activating or directing groups. Therefore, the functionalization of C-H bonds is also attractive for green chemistry. Under oxidative conditions, two C-H bonds or one C-H and one heteroatom-H bond can be transformed to C-C and C-heteroatom bonds, respectively. Often these oxidative coupling reactions require synthetic oxidants, expensive catalysts or high temperatures. Here, we describe a two-step procedure to functionalize indole derivatives, more specifically tetrahydrocarbazoles, by C-H amination using only elemental oxygen as oxidant. The reaction uses the principle of C-H functionalization via Intermediate PeroxideS (CHIPS). In the first step, a hydroperoxide is generated oxidatively using visible light, a photosensitizer and elemental oxygen. In the second step, the N-nucleophile, an aniline, is introduced by Brønsted-acid catalyzed activation of the hydroperoxide leaving group. The products of the first and second step often precipitate and can be conveniently filtered off. The synthesis of a biologically active compound is shown.

Target Capture during Mos1 Transposition*

PubMed Central

Pflieger, Aude; Jaillet, Jerôme; Petit, Agnès; Augé-Gouillou, Corinne; Renault, Sylvaine

2014-01-01

DNA transposition contributes to genomic plasticity. Target capture is a key step in the transposition process, because it contributes to the selection of new insertion sites. Nothing or little is known about how eukaryotic mariner DNA transposons trigger this step. In the case of Mos1, biochemistry and crystallography have deciphered several inverted terminal repeat-transposase complexes that are intermediates during transposition. However, the target capture complex is still unknown. Here, we show that the preintegration complex (i.e., the excised transposon) is the only complex able to capture a target DNA. Mos1 transposase does not support target commitment, which has been proposed to explain Mos1 random genomic integrations within host genomes. We demonstrate that the TA dinucleotide used as the target is crucial both to target recognition and in the chemistry of the strand transfer reaction. Bent DNA molecules are better targets for the capture when the target DNA is nicked two nucleotides apart from the TA. They improve strand transfer when the target DNA contains a mismatch near the TA dinucleotide. PMID:24269942

Target capture during Mos1 transposition.

PubMed

Pflieger, Aude; Jaillet, Jerôme; Petit, Agnès; Augé-Gouillou, Corinne; Renault, Sylvaine

2014-01-03

DNA transposition contributes to genomic plasticity. Target capture is a key step in the transposition process, because it contributes to the selection of new insertion sites. Nothing or little is known about how eukaryotic mariner DNA transposons trigger this step. In the case of Mos1, biochemistry and crystallography have deciphered several inverted terminal repeat-transposase complexes that are intermediates during transposition. However, the target capture complex is still unknown. Here, we show that the preintegration complex (i.e., the excised transposon) is the only complex able to capture a target DNA. Mos1 transposase does not support target commitment, which has been proposed to explain Mos1 random genomic integrations within host genomes. We demonstrate that the TA dinucleotide used as the target is crucial both to target recognition and in the chemistry of the strand transfer reaction. Bent DNA molecules are better targets for the capture when the target DNA is nicked two nucleotides apart from the TA. They improve strand transfer when the target DNA contains a mismatch near the TA dinucleotide.

Scanning sequences after Gibbs sampling to find multiple occurrences of functional elements

PubMed Central

Tharakaraman, Kannan; Mariño-Ramírez, Leonardo; Sheetlin, Sergey L; Landsman, David; Spouge, John L

2006-01-01

Background Many DNA regulatory elements occur as multiple instances within a target promoter. Gibbs sampling programs for finding DNA regulatory elements de novo can be prohibitively slow in locating all instances of such an element in a sequence set. Results We describe an improvement to the A-GLAM computer program, which predicts regulatory elements within DNA sequences with Gibbs sampling. The improvement adds an optional "scanning step" after Gibbs sampling. Gibbs sampling produces a position specific scoring matrix (PSSM). The new scanning step resembles an iterative PSI-BLAST search based on the PSSM. First, it assigns an "individual score" to each subsequence of appropriate length within the input sequences using the initial PSSM. Second, it computes an E-value from each individual score, to assess the agreement between the corresponding subsequence and the PSSM. Third, it permits subsequences with E-values falling below a threshold to contribute to the underlying PSSM, which is then updated using the Bayesian calculus. A-GLAM iterates its scanning step to convergence, at which point no new subsequences contribute to the PSSM. After convergence, A-GLAM reports predicted regulatory elements within each sequence in order of increasing E-values, so users have a statistical evaluation of the predicted elements in a convenient presentation. Thus, although the Gibbs sampling step in A-GLAM finds at most one regulatory element per input sequence, the scanning step can now rapidly locate further instances of the element in each sequence. Conclusion Datasets from experiments determining the binding sites of transcription factors were used to evaluate the improvement to A-GLAM. Typically, the datasets included several sequences containing multiple instances of a regulatory motif. The improvements to A-GLAM permitted it to predict the multiple instances. PMID:16961919

Elements of a Science of Education

ERIC Educational Resources Information Center

Kalantzis, Mary

2006-01-01

Education has become a domain of considerable ideological division. Today the mantra is freedom and choice, yet at the same time, a push to "back to basics" is observed. This author attempts to trace the contours of this division by taking two steps back from the contemporary fray. One step is to situate present day discussions in a larger…

Literacy and the Millennium Development Goals: One Step Forward, Two Steps Backwards

ERIC Educational Resources Information Center

Gomez, Sofia Valdivielso

2005-01-01

Traditionally women have been signified to be "for others", never for themselves. This conceptualisation is also present in the discourses about literacy. The traditional discourse justifies women's literacy based on the need to improve family health, well-being, educational access, and so on. Thus, it is seen as a tool for other ends…

Nigeria: One Step Forward, Two Steps Back

DTIC Science & Technology

2012-11-02

the root causes of societal conflict. An analysis of the cultural and political identities of ethnicity, religion and regional affiliation provide a...governance. 15. SUBJECT TERMS Nigerian Culture and Society 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES...ii Contents Introduction 1 Section 1 Geographic impacts on Nigerian culture 1 Nigerian pre-independence history 3

Computer-Based Feedback in Linear Algebra: Effects on Transfer Performance and Motivation

ERIC Educational Resources Information Center

Corbalan, Gemma; Paas, Fred; Cuypers, Hans

2010-01-01

Two studies investigated the effects on students' perceptions (Study 1) and learning and motivation (Study 2) of different levels of feedback in mathematical problems. In these problems, an error made in one step of the problem-solving procedure will carry over to the following steps and consequently to the final solution. Providing immediate…

'The First Step Is the Two-Step': Hegemonic Masculinity and Dancing in a Country-Western Gay Bar

ERIC Educational Resources Information Center

Johnson, Corey W.

2005-01-01

Gay men are often rendered feminized males according to masculine, heterosexual ideologies. This research demonstrates that gay men are actually more creative and active agents in their gender performance, simultaneously resisting and reinforcing dominant ideologies around gender and sexuality. One context where the creative agency of gay men is…

Hexagonalization of correlation functions II: two-particle contributions

NASA Astrophysics Data System (ADS)

Fleury, Thiago; Komatsu, Shota

2018-02-01

In this work, we compute one-loop planar five-point functions in N=4 super-Yang-Mills using integrability. As in the previous work, we decompose the correlation functions into hexagon form factors and glue them using the weight factors which depend on the cross-ratios. The main new ingredient in the computation, as compared to the four-point functions studied in the previous paper, is the two-particle mirror contribution. We develop techniques to evaluate it and find agreement with the perturbative results in all the cases we analyzed. In addition, we consider next-to-extremal four-point functions, which are known to be protected, and show that the sum of one-particle and two-particle contributions at one loop adds up to zero as expected. The tools developed in this work would be useful for computing higher-particle contributions which would be relevant for more complicated quantities such as higher-loop corrections and non-planar correlators.

A Pearson Random Walk with Steps of Uniform Orientation and Dirichlet Distributed Lengths

NASA Astrophysics Data System (ADS)

Le Caër, Gérard

2010-08-01

A constrained diffusive random walk of n steps in ℝ d and a random flight in ℝ d , which are equivalent, were investigated independently in recent papers (J. Stat. Phys. 127:813, 2007; J. Theor. Probab. 20:769, 2007, and J. Stat. Phys. 131:1039, 2008). The n steps of the walk are independent and identically distributed random vectors of exponential length and uniform orientation. Conditioned on the sum of their lengths being equal to a given value l, closed-form expressions for the distribution of the endpoint of the walk were obtained altogether for any n for d=1,2,4. Uniform distributions of the endpoint inside a ball of radius l were evidenced for a walk of three steps in 2D and of two steps in 4D. The previous walk is generalized by considering step lengths which have independent and identical gamma distributions with a shape parameter q>0. Given the total walk length being equal to 1, the step lengths have a Dirichlet distribution whose parameters are all equal to q. The walk and the flight above correspond to q=1. Simple analytical expressions are obtained for any d≥2 and n≥2 for the endpoint distributions of two families of walks whose q are integers or half-integers which depend solely on d. These endpoint distributions have a simple geometrical interpretation. Expressed for a two-step planar walk whose q=1, it means that the distribution of the endpoint on a disc of radius 1 is identical to the distribution of the projection on the disc of a point M uniformly distributed over the surface of the 3D unit sphere. Five additional walks, with a uniform distribution of the endpoint in the inside of a ball, are found from known finite integrals of products of powers and Bessel functions of the first kind. They include four different walks in ℝ3, two of two steps and two of three steps, and one walk of two steps in ℝ4. Pearson-Liouville random walks, obtained by distributing the total lengths of the previous Pearson-Dirichlet walks according to some specified probability law are finally discussed. Examples of unconstrained random walks, whose step lengths are gamma distributed, are more particularly considered.

Virtual Presence: One Step Beyond Reality

NASA Technical Reports Server (NTRS)

Budden, Nancy Ann

1997-01-01

Our primary objective was to team up a group consisting of scientists and engineers from two different NASA cultures, and simulate an interactive teleoperated robot conducting geologic field work on the Moon or Mars. The information derived from the experiment will benefit both the robotics team and the planetary exploration team in the areas of robot design and development, and mission planning and analysis. The Earth Sciences and Space and Life Sciences Division combines the past with the future contributing experience from Apollo crews exploring the lunar surface, knowledge of reduced gravity environments, the performance limits of EVA suits, and future goals for human exploration beyond low Earth orbit. The Automation, Robotics. and Simulation Division brings to the table the technical expertise of robotic systems, the future goals of highly interactive robotic capabilities, treading on the edge of technology by joining for the first time a unique combination of telepresence with virtual reality.

Rapid comprehensive characterization of crude oils by thermogravimetry coupled to fast modulated gas chromatography-single photon ionization time-of-flight mass spectrometry.

PubMed

Wohlfahrt, S; Fischer, M; Saraji-Bozorgzad, M; Matuschek, G; Streibel, T; Post, E; Denner, T; Zimmermann, R

2013-09-01

Comprehensive multi-dimensional hyphenation of a thermogravimetry device (i.e. a thermobalance) to gas chromatography and single photon ionization-time-of-flight mass spectrometry (TG-GC×SPI-MS) has been used to investigate two crude oil samples of different geographical origin. The source of the applied vacuum ultraviolet radiation is an electron beam pumped rare gas excimer lamp (EBEL). The soft photoionization favors the formation of molecular ions. Introduction of a fast, rapidly modulated gas chromatographic separation step in comparison with solely TG-SPI-MS enables strongly enhanced detection especially with such highly complex organic matrices as crude oil. In contrast with former TG-SPI-MS measurements, separation and identification of overlying substances is possible because of different GC retention times. The specific contribution of isobaric compounds to one mass signal is determined for alkanes, naphthalenes, alkylated benzenes, and other compounds.

Amination of activated carbon for enhancing phenol adsorption: Effect of nitrogen-containing functional groups

NASA Astrophysics Data System (ADS)

Yang, Guo; Chen, Honglin; Qin, Hangdao; Feng, Yujun

2014-02-01

To study the contribution of different nitrogen-containing functional groups to enhancement of phenol adsorption, the aminated activated carbons (AC) were characterized by N2 adsorption/desorption, XPS, Boehm titration, and pH drift method and tested for adsorption behaviors of phenol. Adsorption isotherm fitting revealed that the Langmuir model was preferred for the aminated ACs. The adsorption capacity per unit surface area (qm/SSABET) was linearly correlated with the amount of pyridinic and pyrrolic N, which suggested that these two functional groups played a critical role in phenol adsorption. The enhancement of adsorption capacity was attributed to the strengthened π-π dispersion between phenol and basal plane of AC by pyridinic, pyrrolic N. The adsorption kinetics was found to follow the pseudo-second-order kinetic model, and intraparticle diffusion was one of the rate-controlling steps in the adsorption process.

Commentary: is CIT today's lobotomy?

PubMed

Geller, Jeffrey L

2008-01-01

Birthed in Memphis, Tennessee, in 1988, Crisis Intervention Teams (CITs) have had remarkable growth spurts with few, if any, developmental milestones to document their progress. Compton and colleagues investigated the evidence basis for CIT and found very little. They perhaps found even more than there actually is. There are contributions to CIT outcomes that are rooted in local variations in mental health services and regional culture. These are considered in this commentary, using Memphis as the example. None of us should be surprised that reform is evidence-absent. The mental illness delivery system and the criminal justice system have been instituting reform, and these reforms have had reverberating changes between the two systems, with little or no data to support the changes, for centuries. That there would be unexpected consequences should be obvious. But apparently not so evident that we don't continue to take one blind step after another. Is CIT on firm footing, or just another fool's journey?

Improving the nutritional value of Golden Rice through increased pro-vitamin A content.

PubMed

Paine, Jacqueline A; Shipton, Catherine A; Chaggar, Sunandha; Howells, Rhian M; Kennedy, Mike J; Vernon, Gareth; Wright, Susan Y; Hinchliffe, Edward; Adams, Jessica L; Silverstone, Aron L; Drake, Rachel

2005-04-01

"Golden Rice" is a variety of rice engineered to produce beta-carotene (pro-vitamin A) to help combat vitamin A deficiency, and it has been predicted that its contribution to alleviating vitamin A deficiency would be substantially improved through even higher beta-carotene content. We hypothesized that the daffodil gene encoding phytoene synthase (psy), one of the two genes used to develop Golden Rice, was the limiting step in beta-carotene accumulation. Through systematic testing of other plant psys, we identified a psy from maize that substantially increased carotenoid accumulation in a model plant system. We went on to develop "Golden Rice 2" introducing this psy in combination with the Erwinia uredovora carotene desaturase (crtI) used to generate the original Golden Rice. We observed an increase in total carotenoids of up to 23-fold (maximum 37 microg/g) compared to the original Golden Rice and a preferential accumulation of beta-carotene.

Controllable Magnetization Processes Induced by Nucleation Sites in Permalloy Rings

NASA Astrophysics Data System (ADS)

Chen, Ying-Jiun; Hsu, Chia-Jung; Liao, Chun-Neng; Huang, Hao-Ting; Lee, Chiun-Peng; Chiu, Yi-Hsun; Tung, Tzu-Yun; Lai, Mei-Feng

2010-02-01

Different arrangements of notches as nucleation sites are demonstrated experimentally and numerically to effectively control the magnetization processes of permalloy rings. In the ring with notches at the same side with respect to field direction, two same-helicity vortex domain walls in the onion state lead to two-step switching going through flux-closure state; in the ring with diagonal notches two opposite-helicity vortex domain walls lead to one-step switching skipping flux-closure state. The switching processes are repeatable in contrast to rings without notches where helicites of two vortex domain walls are random so the switching processes can not be controlled.

Positronium formation at Si surfaces

NASA Astrophysics Data System (ADS)

Kawasuso, A.; Maekawa, M.; Miyashita, A.; Wada, K.; Kaiwa, T.; Nagashima, Y.

2018-06-01

Positronium formation at Si(111) and Si(001) surfaces has been investigated by changing the doping level systematically over the range 300-1000 K. The temperature dependence of the positronium fraction varied with the doping condition, and there were practically no differences between the two surface orientations. In heavily doped n -type Si (n ≳1018cm-3) , the positronium fraction (IPs) increased above 700 K and reached more than 95% at 1000 K. In undoped and lightly doped Si (n , p ≲1015cm-3 ), IPs decreased from 300 to 500 K and increased above 700 K. In heavily doped p -type Si (p ≳1018cm-3 ), IPs increased in two steps: one at 500-600 K and one above 700 K. Overall, the positronium fraction increased with the amount of n -type doping. These phenomena were found to be dominated by two kinds of positronium with energies of 0.6-1.5 eV and 0.1-0.2 eV, which were attributed to the work-function mechanism and the surface-positron-mediated process, respectively, with contributions from conduction electrons. The positron work function was estimated to be positive. This agrees with first-principles calculation. The positive positron work function implies that the formation of excitonic electron-positron bound states begins in the bulk subsurface region and transits to the final positronium state in the vacuum.

Accurate upwind methods for the Euler equations

NASA Technical Reports Server (NTRS)

Huynh, Hung T.

1993-01-01

A new class of piecewise linear methods for the numerical solution of the one-dimensional Euler equations of gas dynamics is presented. These methods are uniformly second-order accurate, and can be considered as extensions of Godunov's scheme. With an appropriate definition of monotonicity preservation for the case of linear convection, it can be shown that they preserve monotonicity. Similar to Van Leer's MUSCL scheme, they consist of two key steps: a reconstruction step followed by an upwind step. For the reconstruction step, a monotonicity constraint that preserves uniform second-order accuracy is introduced. Computational efficiency is enhanced by devising a criterion that detects the 'smooth' part of the data where the constraint is redundant. The concept and coding of the constraint are simplified by the use of the median function. A slope steepening technique, which has no effect at smooth regions and can resolve a contact discontinuity in four cells, is described. As for the upwind step, existing and new methods are applied in a manner slightly different from those in the literature. These methods are derived by approximating the Euler equations via linearization and diagonalization. At a 'smooth' interface, Harten, Lax, and Van Leer's one intermediate state model is employed. A modification for this model that can resolve contact discontinuities is presented. Near a discontinuity, either this modified model or a more accurate one, namely, Roe's flux-difference splitting. is used. The current presentation of Roe's method, via the conceptually simple flux-vector splitting, not only establishes a connection between the two splittings, but also leads to an admissibility correction with no conditional statement, and an efficient approximation to Osher's approximate Riemann solver. These reconstruction and upwind steps result in schemes that are uniformly second-order accurate and economical at smooth regions, and yield high resolution at discontinuities.

Optimization of cryoprotectant loading into murine and human oocytes.

PubMed

Karlsson, Jens O M; Szurek, Edyta A; Higgins, Adam Z; Lee, Sang R; Eroglu, Ali

2014-02-01

Loading of cryoprotectants into oocytes is an important step of the cryopreservation process, in which the cells are exposed to potentially damaging osmotic stresses and chemical toxicity. Thus, we investigated the use of physics-based mathematical optimization to guide design of cryoprotectant loading methods for mouse and human oocytes. We first examined loading of 1.5 M dimethyl sulfoxide (Me(2)SO) into mouse oocytes at 23°C. Conventional one-step loading resulted in rates of fertilization (34%) and embryonic development (60%) that were significantly lower than those of untreated controls (95% and 94%, respectively). In contrast, the mathematically optimized two-step method yielded much higher rates of fertilization (85%) and development (87%). To examine the causes for oocyte damage, we performed experiments to separate the effects of cell shrinkage and Me(2)SO exposure time, revealing that neither shrinkage nor Me(2)SO exposure single-handedly impairs the fertilization and development rates. Thus, damage during one-step Me(2)SO addition appears to result from interactions between the effects of Me(2)SO toxicity and osmotic stress. We also investigated Me(2)SO loading into mouse oocytes at 30°C. At this temperature, fertilization rates were again lower after one-step loading (8%) in comparison to mathematically optimized two-step loading (86%) and untreated controls (96%). Furthermore, our computer algorithm generated an effective strategy for reducing Me(2)SO exposure time, using hypotonic diluents for cryoprotectant solutions. With this technique, 1.5 M Me(2)SO was successfully loaded in only 2.5 min, with 92% fertilizability. Based on these promising results, we propose new methods to load cryoprotectants into human oocytes, designed using our mathematical optimization approach. Copyright © 2013 Elsevier Inc. All rights reserved.

Optimization of Cryoprotectant Loading into Murine and Human Oocytes

PubMed Central

Karlsson, Jens O.M.; Szurek, Edyta A.; Higgins, Adam Z.; Lee, Sang R.; Eroglu, Ali

2014-01-01

Loading of cryoprotectants into oocytes is an important step of the cryopreservation process, in which the cells are exposed to potentially damaging osmotic stresses and chemical toxicity. Thus, we investigated the use of physics-based mathematical optimization to guide design of cryoprotectant loading methods for mouse and human oocytes. We first examined loading of 1.5 M dimethylsulfoxide (Me2SO) into mouse oocytes at 23°C. Conventional one-step loading resulted in rates of fertilization (34%) and embryonic development (60%) that were significantly lower than those of untreated controls (95% and 94%, respectively). In contrast, the mathematically optimized two-step method yielded much higher rates of fertilization (85%) and development (87%). To examine the causes for oocyte damage, we performed experiments to separate the effects of cell shrinkage and Me2SO exposure time, revealing that neither shrinkage nor Me2SO exposure single-handedly impairs the fertilization and development rates. Thus, damage during one-step Me2SO addition appears to result from interactions between the effects of Me2SO toxicity and osmotic stress. We also investigated Me2SO loading into mouse oocytes at 30°C. At this temperature, fertilization rates were again lower after one-step loading (8%) in comparison to mathematically optimized two-step loading (86%) and untreated controls (96%). Furthermore, our computer algorithm generated an effective strategy for reducing Me2SO exposure time, using hypotonic diluents for cryoprotectant solutions. With this technique, 1.5 M Me2SO was successfully loaded in only 2.5 min, with 92% fertilizability. Based on these promising results, we propose new methods to load cryoprotectants into human oocytes, designed using our mathematical optimization approach. PMID:24246951

Assembly of high density lipoprotein by the ABCA1/apolipoprotein pathway.

PubMed

Yokoyama, Shinji

2005-06-01

Mammalian somatic cells do not catabolize cholesterol and therefore need to export it for sterol homeostasis at the levels of cells and whole bodies. This mechanism may reduce intracellularly accumulated cholesterol in excess, and thereby would contribute to the prevention or cure of the initial stage of atherosclerotic vascular lesions. HDL is thought to play a main role in this reaction on the basis of epidemiological evidence and in-vitro experimental data. Two independent mechanisms have been identified for this reaction. One is non-specific diffusion-mediated cholesterol 'efflux' from the cell surface, and cholesterol is trapped by various extracellular acceptors including lipoproteins. Extracellular cholesterol esterification on HDL provides a driving force for the net removal of cell cholesterol, and some cellular factors may enhance this reaction. The other mechanism is an apolipoprotein-mediated process to generate HDL by removing cellular phospholipid and cholesterol. This reaction is mediated by a membrane protein ABCA1, and lipid-free or lipid-poor helical apolipoproteins recruit cellular phospholipid and cholesterol to assemble HDL particles. The reaction is composed of two elements: the assembly of HDL particles with phospholipid by apolipoprotein, and cholesterol enrichment in HDL. ABCA1 is essential for the former step, and the latter step requires further intracellular events. ABCA1 is a rate-limiting factor of HDL assembly and is regulated by transcriptional factors and posttranscriptional factors. Posttranscriptional regulation of ABCA1 involves the modulation of its calpain-mediated degradation.

Contribution of CoA ligases to benzenoid biosynthesis in petunia flowers.

PubMed

Klempien, Antje; Kaminaga, Yasuhisa; Qualley, Anthony; Nagegowda, Dinesh A; Widhalm, Joshua R; Orlova, Irina; Shasany, Ajit Kumar; Taguchi, Goro; Kish, Christine M; Cooper, Bruce R; D'Auria, John C; Rhodes, David; Pichersky, Eran; Dudareva, Natalia

2012-05-01

Biosynthesis of benzoic acid from Phe requires shortening of the side chain by two carbons, which can occur via the β-oxidative or nonoxidative pathways. The first step in the β-oxidative pathway is cinnamoyl-CoA formation, likely catalyzed by a member of the 4-coumarate:CoA ligase (4CL) family that converts a range of trans-cinnamic acid derivatives into the corresponding CoA thioesters. Using a functional genomics approach, we identified two potential CoA-ligases from petunia (Petunia hybrida) petal-specific cDNA libraries. The cognate proteins share only 25% amino acid identity and are highly expressed in petunia corollas. Biochemical characterization of the recombinant proteins revealed that one of these proteins (Ph-4CL1) has broad substrate specificity and represents a bona fide 4CL, whereas the other is a cinnamate:CoA ligase (Ph-CNL). RNA interference suppression of Ph-4CL1 did not affect the petunia benzenoid scent profile, whereas downregulation of Ph-CNL resulted in a decrease in emission of benzylbenzoate, phenylethylbenzoate, and methylbenzoate. Green fluorescent protein localization studies revealed that the Ph-4CL1 protein is localized in the cytosol, whereas Ph-CNL is in peroxisomes. Our results indicate that subcellular compartmentalization of enzymes affects their involvement in the benzenoid network and provide evidence that cinnamoyl-CoA formation by Ph-CNL in the peroxisomes is the committed step in the β-oxidative pathway.

Contribution of CoA Ligases to Benzenoid Biosynthesis in Petunia Flowers[W

PubMed Central

Klempien, Antje; Kaminaga, Yasuhisa; Qualley, Anthony; Nagegowda, Dinesh A.; Widhalm, Joshua R.; Orlova, Irina; Shasany, Ajit Kumar; Taguchi, Goro; Kish, Christine M.; Cooper, Bruce R.; D’Auria, John C.; Rhodes, David; Pichersky, Eran; Dudareva, Natalia

2012-01-01

Biosynthesis of benzoic acid from Phe requires shortening of the side chain by two carbons, which can occur via the β-oxidative or nonoxidative pathways. The first step in the β-oxidative pathway is cinnamoyl-CoA formation, likely catalyzed by a member of the 4-coumarate:CoA ligase (4CL) family that converts a range of trans-cinnamic acid derivatives into the corresponding CoA thioesters. Using a functional genomics approach, we identified two potential CoA-ligases from petunia (Petunia hybrida) petal-specific cDNA libraries. The cognate proteins share only 25% amino acid identity and are highly expressed in petunia corollas. Biochemical characterization of the recombinant proteins revealed that one of these proteins (Ph-4CL1) has broad substrate specificity and represents a bona fide 4CL, whereas the other is a cinnamate:CoA ligase (Ph-CNL). RNA interference suppression of Ph-4CL1 did not affect the petunia benzenoid scent profile, whereas downregulation of Ph-CNL resulted in a decrease in emission of benzylbenzoate, phenylethylbenzoate, and methylbenzoate. Green fluorescent protein localization studies revealed that the Ph-4CL1 protein is localized in the cytosol, whereas Ph-CNL is in peroxisomes. Our results indicate that subcellular compartmentalization of enzymes affects their involvement in the benzenoid network and provide evidence that cinnamoyl-CoA formation by Ph-CNL in the peroxisomes is the committed step in the β-oxidative pathway. PMID:22649270

A Finite Element Procedure for Calculating Fluid-Structure Interaction Using MSC/NASTRAN

NASA Technical Reports Server (NTRS)

Chargin, Mladen; Gartmeier, Otto

1990-01-01

This report is intended to serve two purposes. The first is to present a survey of the theoretical background of the dynamic interaction between a non-viscid, compressible fluid and an elastic structure is presented. Section one presents a short survey of the application of the finite element method (FEM) to the area of fluid-structure-interaction (FSI). Section two describes the mathematical foundation of the structure and fluid with special emphasis on the fluid. The main steps in establishing the finite element (FE) equations for the fluid structure coupling are discussed in section three. The second purpose is to demonstrate the application of MSC/NASTRAN to the solution of FSI problems. Some specific topics, such as fluid structure analogy, acoustic absorption, and acoustic contribution analysis are described in section four. Section five deals with the organization of the acoustic procedure flowchart. Section six includes the most important information that a user needs for applying the acoustic procedure to practical FSI problems. Beginning with some rules concerning the FE modeling of the coupled system, the NASTRAN USER DECKs for the different steps are described. The goal of section seven is to demonstrate the use of the acoustic procedure with some examples. This demonstration includes an analytic verification of selected FE results. The analytical description considers only some aspects of FSI and is not intended to be mathematically complete. Finally, section 8 presents an application of the acoustic procedure to vehicle interior acoustic analysis with selected results.